EAPPC2014 – 5th Euro-Asian Pulsed Power Conference
September 8-12, 2014, Kumamoto, Japan
Abstracts
Wednesday, September 10, 2014
Sessions
Plenary Session PL2
(Centennial Hall)
Oral Session OA3
(Centennial Hall)
Oral Session OB3
(Nigo-kan, LR223)
Poster Session P2
(Nigo-kan, Hall and LR211)
Oral Session OA4
Topics
Prof. John J. Mankowski
Recent Advances in Pulsed Power Research at
Texas Tech University
High Current & High Energy Systems,
Repetitive Systems
High Voltage Insulation,
Non-thermal Discharge Plasmas,
Shock waves
(Nigo-kan, LR223)
OA3-1
–
OA3-6
OB3-1
–
OB3-6
High Voltage Insulations, High Energy Density
Storage, Transmission Lines and Transformers,
Generators & Networks, Modulators and Pulsed
Supplies, Electromagnetic Launchers, High Current
and High Energy Systems,
Industrial Applications, Space & Emerging
Applications, Radiation Sources, Z, X-pinches &
Imploding Liners
Particle Beam Technology, Plasma, Ion & Electron
Sources
P2-1
–
P1-70
Particle Beam Technology
OA4-1
–
OA4-7
Medical & Biological Applications
OB4-1
–
OB4-7
(Centennial Hall)
Oral Session OB4
PL2
Wednesday Morning, September 10, 2014
PL2
Recent Advances in Pulsed Power Research at Texas Tech University John J. Mankowski Center for Pulsed Power & Power Electronics (P3E), Department of Electrical & Computer Engineering, Texas Tech University, USA E-­‐mail: john.mankowski@ttu.edu Recent advances at Texas Tech University in pulsed power are presented. Much progress has been
made in high repetition rate RF sources through the use of advanced materials and drivers. We have
recently demonstrated a vircator-based system which can deliver 50 MW at pulsewidths of 30 nsec and
PRF of 500 Hz for a 1 second duration. We have shown a multi-MW, NLTL based system which can
operate at > 1 kHz for long durations. Work continues on our SiC based photoconductive semiconductor
switches (PCSS). Additionally, we report on advances in electrically small antennas in the HF band.
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Morning, September 10, 2014
OA3-1
Research Progress of Mixed-mode LTD Module
Wang Meng, Zhang Le, Zhou Liangji, Chen Lin, Zou Wenkang, Guo Fan,
Ren Jing, Wang Lingyun and Wang Jie
LAPA, Institute of Fluid Physics, CAEP, P.O.Box.919-108, Mianyang, Sichuan, 621900, China
Abstract: This paper proposes a new concept of mixed-mode LTD(Linear transformer driver) module based on
coaxial Marx brick of gas spark switch，which can give full play to the advantags of both circuit topology of Marx
and LTD module，meanwhile avoid their technical difficulties in a manner. Each brick is a Marx circuit, switches
of only first several stage need external trigger, the others working on self-break mode. Coupling trigger between
Marx bricks will improve the reliability of whole module. The mixed-mode LTD module can effectively reduce the
demand for trigger, reduce the engineering difficulty and improve maintainability of system.The development and
preliminary appraisal of single four-stage Marx have completed.With capacitors charging of ± 40 kV，four-stage
Marx’s current amplitude and rise time are 20 kA and 130 ns(0~100%) on matched 9.1 ohm load, voltage is 175
kV on transmission line,all of them are in good agreement with the simulation results.Besides，strong support to
the mixed-mode LTD module’s next step development has provided with the successful completion of the fourstage Marx’s life appraisal.
E-mail address : fujiabin23@163.com
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Morning, September 10, 2014
OA3-2
Design and Performances of a 3.7MA-40kV-800ns LTD Stage
F.Lassalle1, A.Loyen*1, B.Roques1, T.Chanconie1 and F.Bayol2
1) CEA DAM GRAMAT, F-46500 Gramat, France
2) International Technologies for High Pulsed Power, Thegra, France
Since 1996, CEA Gramat is pursuing the development and the improvement of the microsecond
LTD technology [1]. The SPHINX machine [2] is the first multi-mega-ampere driver based on this
technology. Its applications cover various topics, including radiation effects using Z-pinch loads,
isentropic compression using solid liners [3] and astrophysics. SPHINX uses a parallel-series
combination of 160 LTD stages, each stage composed of 2 bricks. A brick consists in the association of a
low inductance 4 F capacitor with a multi-gap, multi channel switch.
Based on our 10 years-long experience developing, testing and improving LTD stages for the
SPHINX machine and other smaller compact drivers, we decided to develop a new microsecond LTD
stage, named LTD16, capable of delivering a current 8 times higher than the Sphinx one. This stage, or
few such stages, could be used to build multi-mega-ampere compact drivers. With more stages, design
studies show that an efficient upgrade of Sphinx driver is possible; 60 LTD16 stages (6 branches of
10 stages) can make a 25MA-1.4 s driver quite compact (18m diameter).
We present the detailed design of the LTD16 stage which size is 3.9m*3.9m*0.46m. This stage is
made of 16 bricks which store 205kJ for a 80kV charging voltage; the magnetic core is designed to
withstand a 60mV.s integral and the output vacuum line is 1.44m diameter. Insulation of the full stage,
including the new switches, use only atmospheric air and solid dielectrics (no oil, no pressurization nor
drying system). Around 1000 shots on resistive-inductive loads allow a detailed analysis of stage
performances and reliability. These tests are made with a matched (11m ), over-matched (17m ) and
under-matched (9m ) loads of 2.7 nH inductance and charging voltage ranging from 50kV to 80kV. The
results of these tests, made within only 6 weeks after assembly, are compatible with all specifications and
all predicted simulations; this shows the robustness of the design and the high confidence reached in
this microsecond LTD technology. For the matched load, main performances reached at 80kV charging
voltage are: 3.7MA with a 780ns full rise time (rise time 10%-90% is 455ns), jitter 3.6ns and
maximum power 150GW transferred to the load with a 77% energy efficiency (Eload/Estored). This
LTD16 stage can work in horizontal or vertical position; the specific frame developed for this movement
also allows a precise pre-alignment in the prospective of assembling several stages on a rail for a future
machine.
References:
[1] Ph.Monjaux et al., “SYRINX Project : First Results With a 640kJ LTD Accelerator”, proceedings of 11th
IEEE International Pulsed Power Conference, 1997, pages 687-697
[2] F. Lassalle et al., “Status on the Sphinx Machine Based on the 1-µs LTD Technology”, IEEE Trans. On
Plasma Sciences, Volume 36, Issue 2, Part 1, pages 370-377, April 2008.
[3] T.D’Almeida et al. “Microsecond ramp compression of a metallic liner driven by a 5 MA current on
the SPHINX machine using a dynamic load current multiplier pulse shaping”, Physics of Plasmas 20,
092512 (2013)
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Morning, September 10, 2014
OA3-3
Lifetime Prediction of Linear Transformer Driver System
Jiangtao Li, Wenzhong Chen*, Jianhao Li, Weihua Jiang, Xu Zhong and Yue Gu
School of Electrical Engineering, Xi’an Jiaotong University, Xi’an, China
The linear transformer driver (LTD), an important technical route for compact and modular pulsed power
systems, has been developed rapidly in recent years [1],[2].
The reliability and stability of a huge LTD system are crucial to its safe operation and maintenance. The
system reliability is determined by the lifetime of key components, such as the spark gaps and capacitors, and
the fault conditions. It is very important to predict the lifetime of the entire system before put into operation.
However, the mechanism of the system failure is not fully understood and the lifetime prediction model is still
under investigation.
In this paper, a comprehensive LTD circuit model for a module consisting 5 cavities is built considering
the mathematical lifetime model for the key components and the faulty conditions are taken into account as
well. The sensitivity analysis of the key components on system lifetime is carried out and the prediction on system
lifetime is presented correspondingly.
The studied module is composed of 5 cavities in series with 40 bricks in parallel. The distributed
parameter circuit model is built up in Matlab/Simulink taking into consideration of the wave propagation and the
nonlinear characteristics of the magnetic core.
The circuit model of one brick is shown in Fig1. The stray parameters, the trigger jitter of switches, and the
conducting time difference between cathodes and anodes are considered in the model as well. The faulty
conditions including the prefire of switches, short-circuit of the capacitors, the core saturation and the AK gap
flashover are investigated. Detailed discussion will be presented in the full paper.
Providing the lifetime of capacitor abides the normal distribution, and the mathematic expression may be
given according to its working voltage, working frequency and reversal voltage [1]. After each shot of the system,
the working condition for the capacitors changes and so as to its lifetime. The lifetime of the system can be
easily calculated if the probability of switch prefire and trigger jitter are given and assuming they increase with
the number of shots. The predication on the output performance can also be conducted. The relationship
between the peak output voltage and the number of shots is shown in Fig.2. It is clearly observed that the output
voltage decreases dramatically after 3500 shots.
Figure 1. Circuit model for LTD brick
Figure 2.Peak output voltage vs. shots
Sensitivity analysis on the factors affecting system reliability is also carried out in this paper taking into
account of the probability of switch prefire, switch jitter, capacitor failure, core saturation, etc. Based on this,
the requirement of the lifetime for electric components, the optimal working condition for LTD system and
reasonable maintenance cycle are possible to be put forward, which will benefit the reliable and stable operation
of the entire system.
References:
[1] Leckbee J.J, Joshua J.E, et al. "Design, simulation, and fault analysis of a 6.5-MV LTD for flash X-ray
radiography." Plasma Science, IEEE Transactions on 34.5 (2006): 1888-1899.
[2] Rose, D.V., Welch, D.R., et al. " Numerical Analysis of a Pulsed Compact LTD System for Electron BeamDriven Radiography." Plasma Science, IEEE Transactions on 34.5 (2006): 1879 – 1887.
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Morning, September 10, 2014
OA3-4
Experimental Validation of an Electromagnetic Model for a 1-MV Induction
Voltage Cavity
Hao Wei*1,2, Fengju Sun2, Tianxue Liang2, Jianming Guo2,
Aici Qiu1,2 , Jiahui Yin1,2 , and Peitian Con2
1) State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Xi'an,
710049, China
2) State Key Laboratory of Intense Pulsed Radiation Simulation and Effect, Northwest Institute of Nuclear
Technology, Xi'an, 710024, China
Magnetically induction voltage adders (MIVA) are pulsed-power accelerators widely used in some
fields [1]. The induction cavities are basic modules of MIVAs. Multi-stage cavities are stacked to
achieve voltage addition, driving a magnetically insulated transmission line [1]. A three dimensional
electromagnetic model is presented for a single-stage induction cavity, which includes the principal
components within the cavity, such as the azimuthal transmission line, cathode plate, vacuum insulatorstack, and a water-resistor dummy load, et al [2]. This model is able to simulate the propagation of
electromagnetic power from the cavity entry to the load. By means of this model, the characteristics of
the output response and feed current uniformity are analyzed. The EM model is benchmarked against
the single-cavity test. Preliminary experiments of a 1-MV prototype cavity have been done on the “ChenGuang” accelerator, which could provide a 1.0 MV/200 kA pulse using a 5Ω water-filled coaxial line. The
EM model reproduces some electrical measurements. The measured load voltage, load current, and
differential signals of B-dot probes are in good agreement with the EM simulations, indicating this
model is an effective tool to evaluate the electrical performance of induction cavities. In the future, this
EM model will be improved and extended to model an MIVA accelerator with multi-stage cavities
stacked in series.
References:
[1] D. Smith, “Induction voltage adders and the induction accelerator family,” Phys. Rev. Spec. Top.
Accel. Beams, vol. 7, no. 6, p. 064801, Jun 2004.
[2] H. Wei, F. J. Sun, A. C. Qiu, et al, “Optimized Design of Azimuthal Transmission Lines for the Cell
Driven by Two PFLs in Induction Voltage Adders,” IEEE Trans. on Plasma Sci., vol. 41, no. 8, pp. 24212426, Aug. 2013.
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Morning, September 10, 2014
OA3-5
A 10 GW Pulsed Power Generator
Meng Wang, B.M. Novac, I.R. Smith and P. Senior
School of Electronic, Electrical and Systems Engineering, Loughborough University, Loughborough,
Leicestershire LE11 3TU, UK
A repetitive 0.6 MV, 10 GW Tesla-driven Blumlein pulsed power generator, with an overall
energy efficiency in excess of 90% and producing a peak power over 10 GW, was presented at the
International Power Modulator and High Voltage Conference, 2014, June 1-5, Santa Fe, NM, USA.
The present paper describes recent improvements that have been introduced including the 30 Ω oilimmersed coaxial HV resistive load being replaced by a radially-mounted multi-element CuSO4 resistor
coupled to a bipolar pulse conditioning unit. Implementation of this unit is believed to improve the
previous 2.4 ns rise time of the output voltage impulse to a few hundreds of picoseconds. The machine
has a complete PSpice model that has been successfully benchmarked against experimental data and
3-D dynamic Computer Simulation Technology (CST) is used to model both the electromagnetic
bipolar pulse conditioning unit and the various sensors mounted on the machine. The most recent
experimental results will be also presented.
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Morning, September 10, 2014
OA3-6
Pulse Output Control of LTD by Using FPGA
M.R. Ghurbanali*1, H. Sugiyama1, T. Sugai1, A. Tokuchi1,2 and W. Jiang1
1) Extreme Energy-Density Research Institute, Nagaoka University of Technology,Nagaoka 940-2188, Japan
2) Pulsed Power Japan Laboratory, Kusatsu 525-0032, Japan
Pulsed power is a certain amount of electrical energy released in a very short time. Pulsed power is usually
generated by the method of pulse compression where high power is achieved by compressing the time width of a
required amount of energy. In the meantime, it has been realized that a high-power pulse can be obtained by
synchronously releasing many lower power pulses to a common load. In other words, a required peak power can be
obtained by adding up enough numbers of small pulses if they are synchronized. A linear transformer driver (LTD)
is a pulsed-power generation scheme based on this concept [1, 2]. This research specifically explains a role of a
FPGA in output pulse control of the LTD. The LTD stack consisting of thirty modules was used. Each module has
assembled with Capacitors, MOSEFTs, Driver IC, Optic receiver and Diodes. Certain numbers of such components
are connected in parallel to form a module, and a certain number of such modules are added up inductively to form
a stack. For desired output of the LTD, control signal for switching process has significant role. Currently a pulse
generator is being used as an optical control signal source but due to advantages of the FPGA (multiple
synchronization ability for switching process), the control signal source of the LTD was replaced from the pulse
generator to the FPGA. The FPGA (DE0 Nano) which is used has 80 outputs pins, i.e. 80 synchronization levels.
The FPGA process/code was developed to provide control signals to 1-30 LTD modules with different timing. It is
proved if control signals with same timing are provided to certain numbers of modules, output energy of those
modules are stacked. An example for flexibility of FPGA to obtain arbitrary output in the LTD is shown in Fig.
1. Here control signals are released for three groups with each ten modules. Timing of control signals provided to
each group is different. Therefore three output pulses are consisted by ten modules energies. For 1, 3, 6, 10, 15
and 30 group of control signals, FPGA code/process has been developed and the LTD’s output has been
analyzed. For each group of control signals input current, power, output current, and pulse energy has been
studied. It is shown desired output is achievable by varying control signals timing of the LTD. Due to
flexibility and advantages of using the FPGA, it could be used for many industrial and academic areas such as
gas and liquid treatment, high-power pulse lasers and particle accelerators .
FPGA
(Control signal)
LTD stack consisting 30
LTD output energy
modules
Figure 1: Three LTD output energy is obtained by
providing three control signals to three groups with
each ten modules
References:
[1] W. Jiang, A. Tokuchi “Repetitive linear Transformer Driver Using Power MOSFETs” IEEE Trans. Plasma
Sci, VOL. 40, NO.10, pp. 2625-2628, Oct 2012.
[2] W. Jiang, “Solid-state LTD module using power MOSFETs,” IEEE Trans. Plasma Sci., vol.38o.
10, pp.2730-2733, Oct 2010.
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Morning, September 10, 2014
OB3-1
Initial Results from a Megavolt Test Stand for Measuring Pulsed Electrode
Emissions in Vacuumζ
R.J. Allen*, D.D. Hinshelwood, J.W. Schumer and I.M. Rittersdorf
Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375 USA
E-mail:allen@nrl.navy.mil
Recently, we have completed construction of a small test stand for measuring electron and ion
emission from electrode surfaces in vacuum [1]. The pulse generator for the test stand is an L-3 PulseRad
that can provide up to 1 MV pulses with a pulse width of about 50 ns and a current up to 9 kA.
The test stand was first configured to study explosive emission from a cathode surface. The
cathodes design is a very simple three inch diameter disk, which allows for the testing of many samples
at low cost. The initial results to be presented are from the testing of different types of metals, finishes, and
coatings.X-ray, optical and electrical diagnostics are being used to characterize the effects of metal type,
finish and coatings on electron emission. Results will be used to improve the current emission model of a
threshold electric field and turn-on time.
References:
[1] R.J. Allen, D.D. Hinshelwood, J.W. Schumer and I.M. Rittersdorf, “A Megavolt Test Stand for Measuring
Cathode and Anode Emissions with Nanosecond Pulses”, Proceedings of the International Conference
on Plasma Science and High Power Particle Beams 2014, to be published.
ζ
a
Work supported by the Naval Research Laboratory Base Program
National Research Council Research Associate
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Morning, September 10, 2014
OB3-2
Planar Shock Waves Induced by Underwater Nanosecond Pulsed Electric
Discharge and Their Medical Applications
S.H.R. Hosseini*1, H. Akiyama1 and S. Moosavi-Nejad2
Bioelectrics Department, Institute of Pulsed Power Science, Kumamoto University, 2-39-1 Kurokami, Kumamoto,
860-8555, Japan
Department of Anatomy, Fukuoka University School of Medicine, Fukuoka, 814-0180, Japan
The paper presents performance characteristics of a planar underwater shock wave generator designed and
constructed for medical applications. Underwater shock waves have been of interest for various medical
therapies. Despite successful contribution of underwater shock waves in medicine, mechanisms of shock waves
effectiveness/damage are still not well understood. There are two candidate mechanisms to explain shock waves
effects in tissue: cavitation and direct effect. While several studies addressed caviation and its induced micro
jet phenomenon, little has been known about direct effects of shock waves. The present study investigates
direct effects of shear stress produced by impingement of planar cavitation-free underwater shock waves.
Underwater shock waves were generated by nanosecond electric discharges produced by a magnetic pulse
compression circuit (MPC) and point to point electrodes. Input voltage and current were monitored and recorded
during each experiment. The whole sequences of the shock wave generation and propagation were observed by
time-resolved high speed shadowgraph visualization. Pressure histories were measured at different stand-off
distances by using a fiber optic probe hydrophone with 3 ns rise time, fast enough to capture expansion behind the
incident shock wave. The effects of over-pressures and energy density of shock waves during in-vivo experiments
were clarified.
Reference:
S.H.R. Hosseini, V. Menezes, S. Moosavi-Nejad, T. Ohki, A. Nakagawa, T. Tominaga, K. Takayama,
“Development of shock wave assisted therapeutic devices and establishment of shock wave therapy,” Minim.
Invasive Ther., Vol. 15: pp. 230-240, 2006.
H. Hosseini, S. Moosavi-Nejad, H. Akiyama, V. Menezes, “Shock wave interaction with interfaces between
materials having different acoustic impedances,” Appl. Phys. Lett., Vol. 104, 103701 pp. 1- 5, 2014.
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Morning, September 10, 2014
OB3-3
Decrease of Sparkover Voltage with Non-branched Streamer Formation under
High-Repetition Positive Impulse Voltage
Takao Matsumoto*1, Yoichi Inada1, Takeshi Ihara2, Yasuji Izawa1 and Kiyoto Nishijima1
1) Department of Electrical Engineering, Fukuoka University, Fukuoka 814-0180, Japan
2) Sasebo National College of Technology, Nagasaki 857-1193, Japan
Atmospheric-pressure streamer discharge has been extensively-researched in various applications such as
exhaust gas treatment and waste water treatment etc... In these applications, higher discharge- repetition rate is
required in order to increase the throughput of treatment. Therefore, the development of higher-frequency pulse
power source has been highly-advanced recently. However, many researchers have reported that treatment
efficiency decreases with increasing the discharge repetition rate [1]. Additionally, it has been also reported that
sparkover occurs inside the discharge reactor, and in a severe case, the equipment is broken.
For problem-solving, the mechanism of the decrease in sparkover voltage under high-repetition positive
impulse voltage was studied in this work. In the experiment, the electrode configuration was needle-to-plane and
the gap distance was 10 mm. The experiment was conducted under atmospheric air condition. The frequency of
applied impulse voltage f was increased up to 4,000 pulse/sec. (pps). The peak of applied voltage was fixed to 9.0
kV.
As a result, the branch of positive streamer decreased with increasing f. The shape of positive streamer
completely changed to non-branched at f = 4,000 pps. After the transition to non-branched positive streamer,
sparkover occurred by minute increase of f. By gas temperature measurement using spectroscopic method, it was
found that the gas temperature in streamer increased with increasing f. The transition to non-branched positive
streamer progressed with background gas heating. In addition, the time change of gas density between the
electrodes gap after occurrence of non-branched positive streamer was visualized by laser schlieren method. From
this, residual localized gas heating along the non-branched streamer channel was confirmed clearly until just before
a subsequent impulse voltage is applied. We consider that a streamer head preferentially propagated high
temperature (≒ high E/N) region without branching, and non-branched positive streamer was formed consequently.
As a conclusion of this study, it was revealed that the non-branched positive streamer which is a kind of
pre-breakdown phenomena is formed by residual localized gas heating due to high-repetition streamer discharge.
References:
[1] T. Matsumoto, D. Wang, T. Namihira and H. Akiyama, “Process performances of 2 ns pulsed discharge
plasma ”, Japanese Journal of Applied Physics, Vol. 50, pp. 08JF14-1-5, 2011.
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Morning, September 10, 2014
OB3-4
Research on Multilayer DBD Excited by Sub-microsecond Pulse Power at
Atmospheric Air
Jie Li*1, 2，Xi Li1, 2, 3，Pan Dong1, 2, Yutong Xie1, 2，Yuan Wang1, 2，Xiaoguo Jiang1, 2，
Jidong Long1, 2 and Linwen Zhang1, 2
Institute of Fluid Physics, CAEP, P. O. Box 919-150, Mianyang 621900, China
Key Laboratory of Pulsed Power, CAEP, P. O. Box 919-150, Mianyang 621900, China
Graduated School of CEAP, Mianyang 621900, China
Multilayer dielectric barrier discharge can efficiently enlarge the volume of plasma and its interreaction
surface area with materials in vertical space, which seems attractive to the industry application. In this report,
a new plasma generator of DBD structure which has multilayer dielectric barrier boards excited by repetitive submicrosecond pulse power (0~-100kV, 130Hz~1kHz, pulse width 230ns, rise time 120ns) is introduced (shown
in fig.1), and homogeneous plasma has been obtained in atmospheric pressure air. The discharge filaments
can't be distinguished by common camera with the exposure time of 1/17s (shown in fig.2 (a) and (b)).
Experiments of high speed photography with the exposure time of 5ns has been carried out to the discharge with
three layers of dielectric barrier boards with each gap width of 2mm. It can be found that luminescence of
the discharge distributes uniformly throughout the upper and the lower gaps (shown fig. 2 (c) ). Also, time evolution
image of three layers DBD will be introduced in this report. It can be found that the two layers of the luminescent
intensity keeps good consistency with each other, and this indicates that breakdown of each gap layers happens at
the same time in a multilayer DBD.
Preliminary polymer of polytetrafluoroethylene (PTFE) film processing experiments has been done adopting
homogeneous multilayer DBD plasma. By taking measure of the water contact angle, it can be found that
hydrophilism could be effectively improved by the processing of each discharge layer. It is as a basic work for industry
application.
Pulse
Puls
Electrode
Dielect
ICC
V
Ch1
Ch2
D
PTFE
Film
Ch3
Fig.1 Experimental schematic of pulsed multilayer DBD Fig.2 Discharge photos and ICCD image of multilayer DBD
References:
T. Kawasaki, Y. Nakayama, and T. Yamauchi. Multilayer Dielectric Barrier Discharge Using Only Anodic Porous
Alumina as Barriers in Atmospheric-Pressure Air[J]. IEEE TRANSACTIONS ON PLASMA SCIENCE, Vol. 36, no. 4,
pp. 1324-1325, 2008.
J. L. Walsh and M. G. Kong．10ns pulsed atmospheric air plasma for uniform treatment of
polymeric surfaces[J]．Applied Physics Letters, Vol. 91, no. 25, p. 251501, 2007.
H. Ayan, G. Fridman, A. F. Gutsol et al. Nanosecond-pulsed uniform dielectric-barrier discharge[J]. IEEE Trans.
on Plasma Science, Vol. 36, no. 2, pp. 504-508, 2008.
T. Shao, Z. Niu, C. Zhang et al. ICCD Observation of Homogeneous DBD Excitated by Unipolar Nanosecond
Pulses in Open Air[J]. IEEE TRANSACTIONS ON PLASMA SCIENCE, Vol. 39, no. 11, pp. 2062-2063, 2011.
J. Li, X. Li, Y. T. Xie et al. High Speed Imaging Study of DBD Excited by Sub-microsecond Pulse Power at
Atmospheric Air[J]. HIGH POWER LASER AND PARTICLE BEAMS, Vol. 26, no. 4, p. 045035, 2014.
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Morning, September 10, 2014
OB3-5
Pressure Dependency of Plasma Temperature of Pulse Arc Discharge in
Pressurized CO2 up to Supercritical Phase
Tomohiro Furusato*1, Hiroyuki Tanoue2, Takahiro Imamichi2, Miyuki Ota2, Hidenori Akiyama2,
Tomoyuki Fujishima1 and Takahiko Yamashita1
1) Graduate School of Engineering, Nagasaki University, Nagasaki 852-8521, Japan
2) Graduate School of Science and Technology, Kumamoto University, 860-8555, Japan
Recently, studies on the arc discharge in supercritical fluids (SCFs) have begun to catch the attention in the
field of electrical switching because SCFs have some unique physical properties compared with gas and liquid such
as high diffusivity, high thermal conductivity and low viscosity. Dielectric recovery rate estimations were reported
by using supercritical carbon dioxide (SCCO2) and supercritical nitrogen, respectively [1], [2]. However, thus far
these reports have been qualitative estimation; it has not been discussed about plasma temperature which is
significant parameter for a dielectric recovery. The aim of this study is to elucidate the plasma behavior of pulse arc
discharge in SCCO2 by spectroscopic analysis.
A positive nanosecond pulsed voltage was applied to needle to plane electrode, while the gap length was set at
5 mm. Tungsten needle electrode was adopted due to its high melting temperature. Spectroscopic measurements of
pulse arc discharge in SCCO2 were conducted using a Konica Minolta Glacier X Cooled Miniature Fiber-coupled
Spectrometer, which were operated in the broad wavelength range of 200 to 900 nm. The temperature of CO2 was
set at 308 K which is higher than critical temperature Tc = 304 K. The experimental condition of CO2 pressure was
dramatically changed in the broad range of 0.2 to 9 MPa. A supercritical condition of CO2 means that temperature
and pressure are higher than Tc and critical pressure Pc = 7.38 MPa.
A whitish emission from arc discharge was observed by naked eye. In particular, the emission spectrum of
atomic oxygen was clearly observed at 777 and 844 nm under the all measurement pressure range of 0.2 to 9 MPa.
The emission intensity ratio of atomic oxygen between 777 and 844 nm decreased with an increase in pressure. It is
supposed that the plasma temperature in SCCO2 is higher than high pressure gas phase. The accurate plasma
temperature should investigate more in detail.
References:
[1] Z. Yang, S.H.R. Hosseini, T. Kiyan, H. Akiyama, “Post-breakdown dielectric recovery characteristics of
high-pressure liquid CO2 including supercritical phase”, IEEE Trans. Dielect. Elect. Insul., Vol. 21, No. 3, pp.
1089-1094, 2014.
[2] J. Zhang, B. van Heesch, F. Beckers, T. Huiskamp, and G. Pemen, “Breakdown Voltage and Recovery
Rate Estimation of a Supercritical Nitrogen Plasma Switch”, IEEE Trans. Plasma Sci., Vol. 42, pp. 376-383,
2014.
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Morning, September 10, 2014
OB3-6
Spectroscopic Study of Surface Flashover under Pulsed Voltage in Vacuum
Le Xu*, JianJun Deng, Meng Wang, Feng Li and Zun Yang
Institute of Fluid Physics, CAEP, P.O. Box 919-108, Mianyang 621999, China
Since surface flashover becomes a limit factor in pulsed power systems [1-3], lots of work have been done
to figure out its mechanism in the past a few decades. Surface flashover along an insulator is generally divided
into three stages: initiation stage, development (or growth) stage, final discharge stage [4]. However, there still
exist many controversies about its underlying process. Since the optical diagnostic methods can provide more
information in understanding the flashover mechanism than electrical ones, the light emitted during surface
flashover along PTFE was diagnosed by a spectrograph together with an ICCD in this paper. And the spectrum
of laser induced breakdown of PTFE was also recorded as a comparison. The results show that the spectrum of
laser induced breakdown is composed of line spectra which emitted by material elements. While many band
spectra emerge in the spectrum of surface flashover besides the former line spectra, which implies the source of
plasma contains desorbed surface gases as well as vaporized insulator material. This result also verifies the
final discharge stage of flashover model.
References:
[1] J. C. Martin, “Nanosecond pulse techniques”, Proc. IEEE, Vol. 80, pp. 934-945, 1992.
[2] W. A. Stygar, J. A. Lott, T. C. Wagoner, et al., “Improved design of a high-voltage vacuum- insulator
interface”, Phys. Rev. ST Accel. Beams, 8, 050401, 2005.
[3] J. G. Lepold, C. Leibovitz, I. Navon and M. Markovits, “Different approach to pulsed high- voltage
vacuum-insulator design”, Phys. Rev. ST Accel. Beams, 10, 060401, 2007.
[4] H. C. Miller, “Flashover of insulators in vacuum: review of the phenomena and techniques to improve
holdoff voltage”, IEEE Trans. Electr. Insul, Vol. 28, pp. 512-527, 1993.
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-1
Effect of BaTiO3 Nano-powder on the Breakdown Characteristics of the Castor
Oil under Microsecond Pulse
Jian Xu*1, Zicheng Zhang1, Hanwu Yang1, Zhuofeng Liu2 and Jiande Zhang1
1) College of Optoelectronic Science and Engineering, National University of Defense Technology, Changsha
410073, China.
2) College of Aerospace Science and Engineering, National University of Defense Technology, Changsha 410073,
China.
Defense and industrial applications have stimulated intense interest in the pulsed power technology towards
high average power and compact structure. Therefore, it's essential to improve the breakdown characteristics of
liquid dielectrics in the capacitive-energy-storage pulsed power systems. Due to the features of relatively high
energy storage density and environment friendly, castor oil is used as the energy-storage medium in these
systems. However, its permittivity is relatively low (4~6). Some research indicates that the insulating
properties of the traditional oil-paper insulation systems have been improved with nanoparticles [1], and
transformer oil-based nanofluids with TiO2 semiconductive nanoparticles show higher levels of AC and positive
impulse breakdown voltage than that of the pure transformer oils [2]. Inspired by the aforementioned, we intend
to apply the nanotechnology to the microsecond pulse.
In this paper, a new kind of colloidal dielectric fluids is explored by dispersing the BaTiO3 nano- powder
into the castor oil through the ultrasonic treating. Dielectric strength measurements under microsecond pulse
have been carried out in a number of colloidal systems, which have varying nano- powder contents and average
particle diameters. The Tesla transformer and the container with spherical electrodes are used as the pulsed voltage
source and the test cell, respectively.
The experimental results demonstrate that the permittivity of the castor oil-based nanofluids with the BaTiO3
nano-powder rises 2-4 times than that of the ordinary oil, with the breakdown strength and energy storage
density improved. For instance, the breakdown strength of the nanofluid, with 6% mass composition of BaTiO3
nano-powder whose average particle diameter of 100 nm, is 1.55 MV/cm under the microsecond pulse. The
corresponding increase is around 25% compared with that of the ordinary oil. In addition, the energy storage
density reaches up to 800 kJ/m3, while that of the ordinary oil is 400 kJ/m3.
It is furthermore found that, the effects of the castor oil-based nanofluids are different with diverse mass
compositions and particle diameters, and there exists an optimum composition for these nanofluids under the
same particle diameter, where the energy storage density reaches the largest value. Besides, the optimum
compositions vary with the average particle diameters of the nano- powder. All these results proved that the
castor oil modified with the BaTiO3 nano-powder is promising to promote the insulating and energy storage
properties.
References:
[1] Yuxiang Zhong, Yuzhen Lv, Chengrong Li, et al, “Insulating properties and charge characteristics of natural
ester fluid modified by TiO2 semiconductive nanoparticles”, IEEE Trans. Dielectr. Electr. Insul, Vol. 20,
pp. 135-140, 2013.
[2] Yuefan Du, Yuzhen Lv, Chengrong Li, et al, “Effect of electron shallow trap on breakdown
performance of transformer oil-based nanofluids”, Journal of applied physics, Vol. 110, pp. 104104,
2011.
* Email: xujian1207@163.com.
** The work is supported by the National Science Foundation of China (51307175) and Hunan Provincial National
Science Foundation of China (11JJ4056).
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-2
Shock-wave Initiation of a High Explosive Charge to Create Axially Symmetric
Detonation Front
Alexandra Gurinovich*1, Pavel Bogdanovich2 and Alexander Komorny2
1) Research Institute for Nuclear Problems of Belarussian State University, 11 Bobruiskaya str., Minsk, Belarus &
Electrophysical Laboratory, Minsk,Belarus
2) Research Institute of Pulse Processes with Pilot Plant, Institute of Powder Metallurgy, National Academy of
Sciences of Belarus, st. Platonova 12-B, Minsk, 220005 Republic of Belarus
Helical flux compression generators (HFCG) initiated at one end are well-studied and widely used. They have
a relatively high initial inductance (~100 μ H) and long operation time (~100 μ s), which limited by the speed of
the contact point motion. But there are a number of applications in which shorter operation time (~10 μ s) is
required. Such operation time is achievable using HFCGs with simultaneous axial initiation of an explosive
charge, described, e.g. in [1,2]. The explosive charge therein is initiated via a chain of electric detonators,
which causes a heterogeneous structure of the detonation wave and crests on the armature to appear. Seeking to
provide homogeneity and symmetry of the armature expansion, we developed a shock wave initiation unit for
high-explosive (PETN or НМХ) charges to create axially symmetric detonation front. The experiments on the
initiation of high-explosive (PETN or НМХ) charges by a shock wave initiation unit with a lengthy exploding
wire fuse are described. The copper fuse is seeded from a capacitive storage at current density of j (1.31.5)·107 А/см2 and the specific action at the level
∫ j 2 dt=(2.1-2.4)·109
А2·с/см4
(according to [3] the specific action for copper melting is
9 2
4
3.1·10 А ·с/см and for copper explosion 7.2·109А2·с/см4). The design of a shock wave initiation unit for different
charge sensitivity values is described. The operation parameters for key unit components are calculated. The
experimental study of the detonation front geometry at the moment of approaching the free surface of a highexplosive charge is described.
References:
[1] A.G. Zherlitsyn et al.,”Generation of a high-voltage pulse by a flux compression generator with axial
initiation”, Teplofiz. Vys. Temp. (in Russian), Vol. 28 , n.5, pp. 988- 994, 1990.
[2] A.S. Kravchenko et al., “An energy source based on a spiral magnetic-flux compression generator with
simultaneous axial initiation of an explosive charge”, High Temperature, Vol. 42, n.4, pp. 539-544, 2004.
[3] G. A. Mesyats, Pulsed Power, Kluwer Academic, New York, 29-54, 2005.
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-3
The Influence of Temperature on Self-healing Characteristics of Metallized Film
Haoyuan Li, Hua Li, Fuchang Lin, Zhiwei Li, Wen-juan Wang, Bowen Wang and Zhi-jianXu
State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science
and Technology, Wuhan, China
Metallized polypropylene film capacitors (MPPFC) possess characteristics of high energy density and high
working reliability due to the self-healing capability. Self-healing means that the MPPFC will restore its
insulation after a breakdown happened inside with only a sacrifice of tiny capacitance [1]. Thermal aging is one
of the main failure mechanisms in metallized film capacitors. Elevated temperature will not only accelerate the
aging of the dielectric but also influence the characteristics of self-healing. With a self-healing experiment platform,
self-healing experiment under 25 ℃, 60 ℃, 85 ℃ and 120 ℃ is performed, and a pressure of 200 kPa is applied to
simulate the interlayer pressure inside the capacitor. With the increase of temperature, the occurrence probability of
high energy self-healing increases. In self-healing, only a small part of the self-healing energy is consumed in
vaporizing the metal layer around the breakdown point and decomposing the polypropylene film at the
breakdown site, most of the self-healing energy is absorbed by the surrounding polypropylene film. Thus the
temperature of the adjacent polypropylene film may be heated to a temperature above its melting point, and
catastrophic failure may happen inside the capacitor after the high energy self-healings. In this paper, the
influence of temperature on self-healing characteristic is analyzed and the dielectric temperature rise around
the breakdown site when micro-energy self-healing happens is calculated.
And comprehensively, the influence of macro-energy self-healing to MPPFC is investigated.
References:
[1] J.H. Tortai, A. Denat* and N. Bonifaci, “Self-healing of capacitors with metallized film technology:
experimental observations and theoretical model”, Journal of Electrostatics, vol. 53, no. 2, pp. 159-169,
2001.
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-4
Electrode Erosion Characteristics of Repetitive Long-life Gas Spark Switch under
Airtight Condition
Jiawei Wu, Weidong Ding, Ruoyu Han, Yunfei Liu, Haibin Zhou and Qiaojue Liu
State key laboratory of electrical insulation for power equipment, Xi’an Jiaotong University, Xianning West Road,
Xi'an, Shaanxi, 710049, P.R. China
With rapid development of pulse power technology, gas spark switch has broadened its application in
industrial fields [1], such as the extraction of unconventional gas resources. Thus, the repetitive switch needs high
current capability, small breakdown voltage variance, and long lifetime in an airtight cavity. The performance of
switch directly influence the output characteristics of the system, but electrode erosion is inevitable, which may
decrease the self-breakdown voltage and the lifetime [2].
The purpose of this paper was to study the electrode erosion characteristics under adverse condition and to
analyze the failure cause of the switch. A test stand (Fig.1) was established to investigate a two- electrode sparkgap switch made of alloy Cu-W (90wt%) while working in an airtight chamber (1.18L) without gas blowing
system. The whole structure of the switch was shown in Fig.2. The switch was tested with frequency of 0.1Hz,
self-breakdown voltage of 30kV, and load output peak current was ~70kA, output peak instantaneous power was
165MW (Fig.3).
The results show the electrodes’ surfaces have many craters, saliences, and cracks, which are observed by
scanning electron microscope. X-ray photoelectron spectroscopy is used to analyze the composition of PTFE
insulators’ surfaces. Besides, the trend of surface roughness and self-breakdown voltage with increasing operation
times has been performed. This paper analyses the failure cause of the gas spark switch and the reaction between
electrode material and insulator is speculated as the main reason leading to the switch’s failure. Detailed discussion
will be presented in the full paper.
Fig.1 Test platform of the experimental setup
1- Switch chamber’s outer shell 2- Sealing out shell
3- PTFE insulator 4-Electrode stem 5- Hexagon nut
6- Cu-W (90wt%) electrode 7- Cover plate
8- Sealing cover plate 9- Quartz glass plate 10-PTFE gasket
Fig.2 Switch
structure
Fig.3 The waveform of instantaneous
power
structure
References:
[1] Zeng H, Lin F, Cai L, et al. “Study on erosion mechanism of graphite electrode in two-electrode spark gap
switch”, Review of Scientific Instruments, Vol. 83, pp. 013504-013504.5, 2012.
[2] Koutsoubis J M and MacGregor S J, “Electrode erosion and lifetime performance of a high repetition
rate, triggered, corona-stabilized
switch in air”. Journal of Physics D: Applied Physics, Vol. 33, pp. 1093EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
1103, 2000.
Wednesday Afternoon, September 10, 2014
P2-5
Erosion Mechanism and Energy Loss in a 700 kA Graphite-Electrode Gas Switch
Bin Yu, Fuchang Lin, Lee Li, Yi Liu and Yunlong Liu
State Key Laboratory Of Advanced Electromagnetic Engineering And Technology Huazhong University Of Science
And Technology, Wuhan, China
According to the latest requirements of the advanced laser system, a 700 kA gas switch with graphite
electrodes for pulsed power supply module has been developed. The paper describes the design, construction
and testing of the high-current gas switch and its trigger system. Through the analyses of the electrodes
erosion of different materials, high-density graphite is found to be more suitable for electrodes of the high
current and high coulomb gas switch. The two-electrode gas switch was selected, which suffers high peak and fast
rise-time currents. The experimental results show that the measured discharge current is demonstrated to be over
700 kA peak-current and 500 μs pulse- width. The transfer charge per shot is more than 500 coulomb.
Moreover, the erosion mechanism of graphite electrode under the arc was analyzed and the energy loss in
gas switch is numerically studied. The erosion mechanism of the graphite electrode is investigated based on the
theory of thermodynamics, and the operation of the switches is analyzed using the Braginsky model which
allows calculation of the time dependence of the spark channel resistance. Finally, the insulation recovery
problem in the gas switch is studied as well.
References:
[1] P. A. Arnold, S. D. Hulsey, G. T. Ullery, D. E. Petersen, D. L. Pendleton, C.W. Ollis, M. A. Newton, T. B.
Harwell, and L. M. Hadovski, “An update on the status of the NIF power- conditioning system,” IEEE
Trans. Plasma Sci., vol. 36, no. 2, pp. 383–388, Apr. 2008.
[2] L. Lee, G. Liu, H. Zeng, G. Hu, N. Liu, L. Cai, and F. C. Lin, “Design, construction and testing of switches and
trigger generator for 1.2 MJ capacitive pulsed power supply module,” IEEE Trans. Plasma Sci., vol. 39, no. 1,
pp. 294–299, Jan. 2011.
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-6
Estimation of Prefire Probability of Multi Gap Gas Switch for FLTD
Xuandong Liu, Shanhong Liu, Xiaoang Li, Qiaogen Zhang* and Aici Qiu
High Voltage Engineering institute, Xi’an Jiaotong University,Xi’an, Shaanxi Province, China
Prefire of gas switch may dramatically affect the reliability, stability of output pulse of high voltage high
current generators based on fast linear transformer driver (FLTD). This paper presents a mlti gap gas spark switch
for FLTD, as well as the self-breakdown voltages and triggered breakdown voltages with different gas pressures
and charge voltages. The prefire probability was calculated on the basis of breakdown voltage distribution analysis.
Finally, the operational conditions for FLTD gas switch have been proposed.
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-7
Influence of Electromagnetic Field on Arc Motion in a Triggered Vacuum
Switch with Multi-Rod System
Chi Zhang, Ling Dai, Fuchang Lin and Yanzhao Wang
State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and
Technology Wuhan, Hubei, 430074, P. R. China
This paper deals with the influence of electromagnetic field on arc motion in a triggered vacuum switch
with multi-rod system (MTVS). A 3-D model of the MTVS is developed. Based on the model, the electrostatic
field distribution in the MTVS is calculated, especially on the electric field strength in the vicinity of the trigger
unit. To analyze the magnetic field distribution when arc current appears in the MTVS, we use the cylindrical
conductor model to describe the arc column in the MTVS. Under low current condition, assuming MTVS is
conducted with a single arc channel, a single arc column model is used and the magnetic forces on the arc column
of different location in the gap are analyzed. Under high current condition, assuming MTVS is conducted with
multi-arc channel in all gaps, a multi-arc column model is used and the magnetic forces on each arc column is
analyzed. A sample MTVS with transparent tube is designed and fabricated for the vacuum arc observation using
a high speed camera system. Through the observed image data and the 3-D simulation results, it is found that initial
arc discharge mostly appears in the strong electric field region near the trigger unit and the arc motion is affected
by the magnetic force which drives the arc to a certain position in MTVS.
References:
Vozdvijensky V.A.， Sidorov V.A， Initial stage of discharge current growth in a triggered vacuum gap[J] IEEE
Transactions on Plasma Science, Volume 19, 1991 Page(s):778 – 781
Alferov D F, Sidorov V A. Development of a high-current vacuum arc in a rod electrode system[J]. High
temperature, 2001, 39(6): 801-808.
Alferov D F, Nevrovskii V A, Sidorov V A. Anode mode of vacuum arc in a multirod electrode system[J]. High
temperature, 2002, 40(1): 15-20.
Anders A. Cathodic arcs: from fractal spots to energetic condensation[M]. Springer, 2009.
Wang Y, Dai L, Lin F, Optimization of a triggered vacuum switch with multi-rod electrodes system [J]. IEEE
Transactions on Plasma Science, 2014, 42(1): 162-167.
XIU Shi-xin, PANG Xian-hai, ZHANG Min. Computation and Analysis of Magnetic Blowout Forces in Transverse
Magnetic Field Contacts of Vacuum Interrupter[J] VACUUM ELECTRONICS, 2007,05:19-22.
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-8
Lifetime Performance Research of Repetitive Long-life Gas Spark Switch in
Airtight Chamber
Jiawei Wu, Weidong Ding, Ruoyu Han, Yunfei Liu, Qiaojue Liu and Yan Jing
State key laboratory of electrical insulation for power equipment, Xi’an Jiaotong University, Xianning West Road,
Xi'an, Shaanxi, 710049, P.R. China
Switch is one of the key components in the pulsed power system [1]. As one kind of high current closed
switches, the two-electrode gas spark switch made of alloy Cu-W has many advantages such as large charge transfer,
high current capability and long lifetime. Some researchers has designed a series of two electrodes spark gap
switches, which use gas blowing system or electrode cooling system to maintain a stable self-breakdown voltage
(Ub). But few studies has done on repetitive long-life gas spark switch working in airtight chamber with large current.
The purpose of this paper was to study the life performance under airtight condition and to analysis the
operating characteristics and failure cause of the switch. A test stand (Fig.1) was established to investigate a
two-electrode spark-gap switch made of alloy Cu-W (90% mass percent of W, Φ35mm) while working in an
airtight chamber (1.18L) without gas blowing system. The whole structure of the switch was shown in Fig.2. The
switch was tested with operation frequency of 0.1Hz, self-breakdown voltage Ub of 30kV. The load peak current
was ~70kA. The discharge cycle was 12.25μs and the whole discharge process was ~ 130μs. The typical waveforms
of Ub and Ib was shown in Fig.3.
The results showed the trends of self-breakdown voltages and self-breakdown probability with increasing
operation times. Gaussian function was used to analyze self-breakdown probability. Scanning electron microscopy
(SEM) and X-ray photoelectron spectroscopy (XPS) were used to evaluate the structure and composition of the
electrodes for investigating the failure cause. Detailed discussion on lifetime performance and the influential factors
will be presented in the full paper.
Fig.1 Test platform of the experimental setup
Fig.2 Switch structure
Fig.3 Typical voltage and current waveforms of Ub and Ib
References:
[1] Koutsoubis J M and MacGregor S J, “Electrode erosion and lifetime performance of a high repetition
rate, triggered, corona-stabilized switch in air”. Journal of Physics D: Applied Physics, Vol. 33, pp. 1093-1103,
2000.
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-9
Pulsed Breakdown Characteristic of Carbon Nanotube Electrode
T. Ihara, N. Kurosaki, T. Terahira, Y. Yagyu, T. Oshima, H. Kawasaki and Y. Suda
Department of Electrical and Electronic Engineering, National Institute of Technology, Sasebo College, Nagasaki,
857-1193, Japan
Study on nanosecond pulsed discharge have been applied to widely filed such as environmental and medical,
biological [1]. NPD is known as easy formation of non-equilibrium plasma and high energy efficient, high
chemical reaction. In previous work, power supply for generation of NPD is reported using fast semiconductor
and magnetic switch, gap switch [2]. The semiconductor and magnetic switch are required technical
knowledge. On the other hand, pulse generator with gap switch is popular as easy handling and low cost.
However, in the nanosecond time scale, performance of gap switch is unstable by fluctuations in initiation
breakdown voltage. The fluctuation is due to statistical time lag of low existence probability of initial electrons for
triggering discharge.
Here, aim of this study is to stabilization of initiation voltage of pulsed discharge by supplying initial electrons
using carbon nanotube (CNT) electrode as field emission source. The experiment of breakdown characteristic was
carried out under semi-uniform electric field between spherical-to-plane electrode in atmospheric air (298 K,
40 %). Vertically-aligned CNT (Microphase Co., Ltd., substrate materials: SUS) was fixed on electrode by
conductive tape. The pulsed voltage generator was composed with all solid switches. Specifications of pulsed
voltage were maximum value in 30 kV, pulsed width in 1 s. The breakdown characteristics were measured by
shunt resistance at 50
and photomultiplier (HAMAMATSU Photonics, RG955).
The experimental results are shown that CNT electrode becomes stabilized fluctuation of breakdown voltages.
The surface damages on CNT electrode after breakdown experiment is observed by scanning electron microscope.
These results show that CNT electrode has the possibility of applied to nanosecond pulsed gap switch.
References:
[1] H. Akiyama et al., “Industrial Applications of Pulsed Power Technology”, IEEE Trans. Dielectr.
Electr. Insul, Vol. 14, No. 5, pp. 1051-1064, 2007.
[2] J. Mankowski and M Kristiansen, “A review of short pulse generator technology”, IEEE Trans.
Plasma sci., Vol. 28, No. 1, pp.102-108, 2000.
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-10
Study on Gas Spark Switches for Fast Linear Transformer Driver
Xuandong Liu*, Weihao Tie, Shanhong Liu, Peng Liu, Qiaogen Zhang and Aici Qiu High
Voltage Engineering institute, Xi’an Jiaotong University,Xi’an, Shaanxi Province, China
Fast linear transformer driver is a developing technology to generate high voltage high current pulse, which
needs tens of thousands of gas switches to construct large scale facilities for flash X ray photograph,
inertial confinement fusion, etc. Therefore, gas switch is one of the most important components of FLTD.
This paper presents some advances in multi gap gas switch, three -electrode gas switch, and pre ionized gas switch.
Furthermore, a novel gas switch triggered by micro-void spark discharge ejected plasma has been demonstrated,
the performances of self breakdown and triggered breakdown have
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-11
Study on the Influences of Pressure and Gap Length on Electrode Erosion in Gas
Spark Switch
Xiaoang Li, Xuandong Liu*, Xuanqi Gou, Fanhui Zeng and Qiaogen Zhang
State Key Laboratory of Electrical Insulation and Power Equipment, Xi’an Jiaotong University, 710049, Xi’an, China
Gas spark switches are widely used in pulsed power system for their high current capability, stability and low
costs [1]. But electrode erosion is a restrictive factor influencing performance and shortening life time of gas
spark switch [2]. For gas spark switches working in specific voltage and current waveforms, pressure and
gap length in switch cavity can greatly influence the heat flux and dynamic process on electrode surface, and
thus affect electrode erosion properties, but related data are rarely published [3]. In this paper, mass losses and
surface roughness of copper electrodes have been investigated under the same value of pd, and the emission
spectrums have been measured to clarify the influence of pressure. The results show that high pressure and short
gap length will induce a severer electrode erosion under the same current waveform. This is mainly due to the
higher electron density and more frequent energy transfer under high pressure which increases the energy flux
and expedites electrode erosion process.
Key words: gas spark switch, pulsed power system, electrode erosion, gap length, pressure.
References:
[1] J. R. Woodworth, J. A. Alexander, F. R. Gruner, et al. “Low-inductance gas switches for linear transformer
drivers.” Phys. Rev., vol. 12, no. 6, pp. 1-17, June 2009.
[2] H. Wang, Q. G. Zhang, J. Wei, et al. “Research on erosion property of field-distortion gas switch electrode in
nanosecond pulse.” IEEE Trans. Plasma Sci., vol. 40, no. 6, pp. 192-198, Jan. 2012.
[3] H. Wang, Q. G. Zhang, X. Tong, et al. “Study on heat fluxes and theirs effect on electrode material
removal on the copper electrode of a field-distortion gas switch.” Euro. Phys. Lett., vol. 96, no. 4, pp.
45001-1-45001-3, Nov. 2011.
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-12
The Influence of Discharge Products on Surface Properties of Insulators in Highpower Spark Gaps
Yunfei Liu, Mingwei Yan, Jiawei Wu*, Ruoyu Han* and Weidong Ding
State Key Laboratory of Electrical Insulation for Power Equipment, Xi’an Jiaoton University, Xi'an 710049, China
The lifetime of high-power spark gaps is largely determined by surface properties of their inner insulators.
The insulators undergo influences of electrode erosion products, UV irradiation and temperature variation during
the spark discharge [1, 2]. Dielectric properties of the insulator surface may change a lot under those effects,
followed by insulation deterioration and spark gap malfunction. The purpose of this study is to explore the
influence of discharge products on those insulators exposed in spark gaps, and thus give an instruction for structural
optimization.
In this paper, a two-electrode axisymmetric self-breakdown spark gap was designed. Two types of
dismountable electrode tips (flat-head and spherical-head, copper-tungsten CuW70) were used in the experiment.
The working medium in the spark gap was atmospheric air. Polymethyl methacrylate, nylon and
polytetrafluoroethylene insulators were selected as samples fixed around the electrode to receive discharge
products. After a certain number of discharges, surface content (by XPS, Kratos AXIS Ultra DLD), surface
morphology (by metalloscope, Shanghai Wanheng MM-2C) and surface dielectric properties (leakage current and
flashover voltage) of the samples were examined. The spark gap switched an underdamping RC circuit to
generate a peak current of 45 kA oscillatory decay waveform with a duration of 120 μs. The self-breakdown
voltage was 19kV.
XPS analysis shows that chemical element of sample surface contains W, Cu and O, which W exists in the
form of metallic W and WOx compounds and Cu exists in the form of metallic Cu and CuO compounds. From
surface morphology observation, a large number of spherical-crown-shape particles with a diameter of 4-8 μm are
present on the insulator surface. What’s more, the particle numbers decrease with the increasing discharge times.
Along the axial direction, particles mainly distribute near the electrode plane, which is similar to the results
reported before [3]. This phenomenon proves that liquid metal material spatters from the electrodes to insulators
in the tangent direction of discharge spots. Dielectric properties experiment shows that leakage current distribution
along the axial direction appears a V-shape curve, which means that dielectric strength of insulator surface near
the electrodes is higher than that away from the discharge region. Possible reasons for the phenomenon are
discussed. What’s more, dielectric properties of the treated surface are greatly influenced by the ambient humidity
and when relative humidity is less than 30% (295K) the leakage current and flashover voltage almost remain
the same as those of virgin insulators. Therefore, reducing water content in the spark gap (water vapor mixed in
the working medium, absorbed by the insulator or produced in the discharge progress) is an effective method to
improve dielectric strength of the insulators.
This work has been supported by the National High Technology Research and Development Program of
China (2013AA064502).
References:
[1] H. Wang, Q. Zhang, X. Tong, et al. “Study on heat fluxes and their effect on electrode material removal on
the copper electrode of a field-distortion gas spark switch”, Europhysics Letters, Vol. 96, No. 45001, 2011.
[2] G. Jackson, L. Hatfield, M. Kristiansen, et al. “Surface studies of dielectric materials used in spark gaps”,
Journal of Applied Physics, Vol. 55, pp. 262-268, 1984.
[3] J. E. Daalder. “Components of cathode erosion in vacuum arcs”, Journal of Physics D: Applied Physics, Vol.
9, pp. 2379-2395, 1976.
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-13
Visualization of Pulsed Breakdown and Recovery Processes in Liquid and
Supercritical Carbon Dioxide
Takahiro Imamichi*1, Tomohiro Furusato2, Hiroyuki Tanoue1, Miyuki Ota1, S.H.R. Hosseini3,
Sunao Katsuki3 and Hidenori Akiyama3
1) Graduate School of Science and Technology, Kumamoto University, Kumamoto 860-8555,Japan
2) Graduate School of Engineering, Nagasaki University 852-8521, Japan
3) Institute of Pulsed Power Science, Kumamoto University, Kumamoto 860-8555, Japan
Pulsed power switches and circuit breakers require high insulation and fast recovery characteristics. Water is
often used as the medium for pulsed power switches; however, consistent and timely removal of bubbles is
necessary to shorten the dielectric recovery time.
Recently, Supercritical fluids (SCFs) have attracted attention as an electrical switching medium due to their
high breakdown strength and fast dielectric recovery capability compared with water. SCFs also do not present
the problem of latent heat due to vaporization, suggesting that bubbles are not generated under joule heating.
Moreover, both supercritical carbon dioxide (SC CO2) and supercritical nitrogen (SC N2) are more
environmentally friendly than sulfur hexafluoride (SF6), which is commonly used in circuit breakers. These
reasons have driven reports on dielectric recovery characteristics of SC CO2 and SC N2 [1], [2]. However,
detailed dielectric recovery processes of supercritical fluids remain poorly elucidated.
In this study, a positive nanosecond pulsed voltage supplied by a magnetic pulse compression module
(MPC) was applied to a needle electrode in both SC CO2 (T = 305 K, P = 7.5 MPa) and liquid CO2 (T = 293 K, P
= 6.0 MPa). Breakdown and recovery processes in pressurized CO2 were observed by means of Shadowgraph
method with pulsed Nd: YAG laser. The point to plane electrode was adopted to observe the electrical
breakdown and dielectric recovery processes with highly repeatability in the macro range. The peak value of the
applied pulsed voltage and the rise time were 50 kV and 85 ns, respectively. The gap length of the electrode was
d = 4.5 mm. The material of point electrode,
with a tip radius of r = 8 µm, was tungsten, used as its high melting point minimizes erosion.
The experimental results show: (1) A strong light emission resembling an arc channel was observed between
the point to plane electrode; (2) a cylindrical shock wave occurred from the arc channel and propagated; (3) a
low-density region was generated around the channel and expanded; (4) a low- density region similar to
Rayleigh-Taylor instability was initiated; (5) the medium state gradually recovered toward the plane electrode
from the needle electrode. The total dielectric recovery time of SC phase was faster than that of the liquid state.
References:
[1] Z. Yang, S. H. R. Hosseini, T. Kiyan, H. Akiyama, “Post-breakdown dielectric recovery characteristics of
high-pressure liquid CO2 including supercritical phase”, IEEE Trans. Dielectr. Electr. Insul., Vol. 21, pp. 10891094, 2014.
[2] J. Zhang, B. van Heesch, F. Beckers, T. Huiskamp, and G. Pemen, “Breakdown voltage and recovery
rate estimation of a supercritical nitrogen plasma switch”, IEEE Trans. Plasma Sci., Vol. 42, pp. 376-383, 2014.
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-14
A Nonuniform Transmission Line Code for Pulsed Power Z-pinch Drivers
Chongyang Mao, Xiaobing Zou and Xinxin Wang*
Department of Electrical Engineering, Tsinghua University, Beijing 100084, China
Recently, a number of architectures have been proposed for the design of future pulsed power Z-pinch
drivers. In the architectures nonuniform transmission lines were used to combine the outputs of severalhundred terawatt-level pulse generators to produce a petawatt-level pulse. In general, people obtained the output
voltage from a nonuniform transmission line by considering the nonuniform line as a cascaded multiple-section
line and then calculating it with the circuit simulation codes such as PSpice or TLCODE. We also treated the
nonuniform line as a cascaded multiple-section line, but analyzed it with an analytical method. We found that a
mathematical expression of the output voltage from a nonuniform line could be deduced if the impedance profile
of the nonuniform line changes continuously and monotonically and each line section of the cascaded multiplesection line is short enough. The output voltage consists of one primary component called first arriving wave and
numerous double-reflection components. In comparison with the input voltage wave, the first arriving wave is the
same in wave shape and proportional to (Zout / Zin)1/2 in amplitude, where Zout and Zin are the output
impedance and the input impedance of the nonuniform line, respectively. It was shown that the double
reflection components not only lower the output voltage, but also compress the output voltage pulse. The
waveform of the output voltage obtained using our mathematical expression is fully overlapping with that
obtained from the circuit simulation using PSpice, which indicates that our mathematical expression is correct.
Based on the mathematical expression, we wrote a code in MATLAB to calculate the output voltage from a
nonuniform line. In this code, the input voltage was assumed to have a half-sine shape that is the most
frequently used pulse shape for pulsed power devices such as Z-pinch. It takes much less time to calculate the
output voltage using our code than using PSpice.
In order to make our code more friendly and flexible to user, we designed a graphical user interface (GUI)
embedded in MATLAB. With this interface, it is very easy to input all the parameters necessary for the
calculation. Not only the output voltage but also the transmission efficiencies for the voltage and power can be
directly obtained.
*
This work was supported by the National Natural Science Foundation of China under Contract 51277109.
** Author
to whom any correspondence should be addressed.
1
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-15
Circuit Modeling of Yang Accelerator’s Water Transmission Line and MITL
SONG Shengyi, QIU Xu, WEI Bing, GU Yuanchao and XIE Weiping
LAPA, Institute of Fluid Physics, CAEP, P.O.Box.919-108, Mianyang, Sichuan, 621900, China
A circuit model for Yang accelerator’s water transmission line and magnetically insulated
transmission line (MITL), based on their impedance characteristics, has been employed to simulate the
experiments, among which the one for a shorted load is perfectly modeled and the other for a wire array
load, however, can not be accurately modeled unless introducing a series load. With the aid of the model,
the typical implosion characteristics of wire array loads have also been discussed. The comparison of the
calculated results by the model with the experimental ones, indicates that the model is validated and is
available for design and analysis of both the Yang accelerator’s water transmission line and MITL.
Key words: Yang accelerator; Magnetically insulated transmission line; Circuit model; Wire array implosion
E-mail address : fujiabin23@163.com
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-16
Design of Compact Feed-through for 500 kV High Voltage Cable
L. Véron1, J.C. Brion2 and R. Rosol3
1) CEA, DAM, DIF, Bruyères-le-Châtel, 91297 Arpajon, France
2) EUROPULSE, route de Gignac, 46600 Cressensac, France
3) CERN, TE/ABT/FPS, CH-1211 Genève 23, Switzerland
This paper presents the design and electrical simulations of a high voltage feed-through working at 500 kV
into atmospheric pressure or primary vacuum.
Operational needs and technical considerations have been taken into account to design this component.
The high pulsed voltage (500 kV - 50 ns), the limited size (maximum diameter: 100 mm), the possibility to work
into a primary vacuum (10-2 mbar) and our given cable (Z = 56 ) have been the input data. The impedance
matching of the feed-through has been specially optimized to avoid voltage reflection and drastic deformation
of the voltage and current shape.
Many tests into DC voltage (60 kV) and pulsed voltage (500 kV) have been performed to optimize it. For
some applications into a primary vacuum, it can be possible to pressurize the feed-through to avoid surface
flashover.
Today, this robust connector is frequently used for many applications, especially for flash radiography.
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-17
Performance Evaluation of Pulse Transformer Based Modulators with Very Fast
Rise Times for Plasma Channel Drilling
Tonis Hobejogi and Juergen Biela
Laboratory for High Power Electronic Systems ETH Zurich, www.hpe.ee.ethz.ch
Plasma Channel Drilling (PCD), which utilizes high voltage pulses with very short rise times for
disintegrating rocks, is an interesting concept to improve drilling efficiency [1-2]. The most common way for
generating the high voltage pulses are Marx generators based on spark gaps. However, the size of such generators
is one of the main disadvantage. Therefore, in this paper a compact and durable modulator, using a 4.5kV
semiconductor switch in combination with pulse compression, is presented.
As will be shown, a pulse transformer itself is not able to provide fast enough rise times for PCD
(Trise<100ns). Therefore, systems with a pulse transformer and pulse compression are investigated. First, single and
two stage magnetic pulse compression (MPC) systems are discussed [2], thereafter a system based on a triggered
spark gap is described and compared with the MPC systems.
For validating the investigated concept utilizing a triggered spark gap a prototype has been built. With the
prototype the fragmentation energy required for PCD has been measured for dry concrete. The measurement
points of the energy incl. trend-lines are shown in the figure above and are discussed as well as compared with
literature findings in the paper.
Based on the prototype system, comprehensive converter models have been developed and validated. With
these models an optimal design of the triggered spark gap concept with the focus on a compact design and high
pulse voltage has been designed and is presented in the paper. The resulting system concept is shown in the
figure above and would fit in a box of 330x375x445mm (without charging system).
References:
[1] Lisitsyn, I.V., Inoue, H., Nishizawa, I., Katsuki, S. & Akiyama, H. (1998), "Breakdown and destruction of
heterogeneous solid dielectrics by high voltage pulses", Journal of Applied Physics.
Vol. 84(11), pp. 6262-6267
[2] Biela et al., “Solid State Modulator for Plasma Channel Drilling”, IEEE Transactions on Dielectrics and Electrical
Insulation, 2009, vol.16
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-18
Modeling of Electromagnetic Induction Launcher
Dae-Hwan Kwak*1, Yun Sik Jin2, Young Bae Kim2, Jong Soo Kim2, Chuhyun Cho2 , Kyung-Seung Yang3,
Seong-Ho Kim3, Byung-Ha Lee3, Sanghyuk An3, Young-Hyun Lee3, Seok Han Yoon3, In Su Koo4
and Yong Gi Baik4
1)
2)
3)
4)
Korea University of Science and Technology
Korea Electrotechnology Research Institute, Changwon, 642-120, Korea
Defense Advanced R&D Center, Agency for Defense Development, Daejeon, 305-150, Korea
Hyundae-Wia Corporation, Changwon, 642-110, Korea
Electromagnetic induction launcher (EIL) which uses the repulsive force between driving coil current and
induced projectile eddy current have received great attention because of noncontact advantage. For multiple stages
acceleration of projectile within EIL, appropriate coil form and triggering time of coil current should be
determined. In this paper we describe the modeling of 3-stage EIL for the acceleration of a Cu cylindrical block
with 50 kg mass and 290 mm diameter. The EIL consists of three independent driving coils and three pulsed
power modules for powering the drive coils. By using an electromagnetic analysis simulation program, the
shape and positions of driving coils, the appropriate starting position and triggering position of the moving
projectile, and the conditions of the pulsed power modules have been calculated. The modeling results showed
that the projectile could be accelerated from rest t
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-19
Simulation on Electromagnetic Radiation of the 20-kJ Pulse Forming Unit for
Electromagnetic Launcher
Xiaolong Guo, Ling Dai, Fuchang Lin, Xu Chen and Xu Wang
State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science
and Technology, Wuhan 430074, China
A 20-kJ pulse forming unit (PFU) for electromagnetic launcher has been designed. The PFU is
comprised of a high energy density capacitor (3270 μF/3.5 kV), a 4 inches thyristor, a pulse shaping inductor
(1.5 μH) and a crowbar diode. Parameters of each part in the PFU have been elaborated to maintain a high
efficiency of the power system. The peak value of the output current is 60 kA with a peak time of 245 μs. The
PFU will produce strong electromagnetic radiation when discharging, which will affect the performance of
electronic devices in charger or trigger system. It is necessary to reduce the electromagnetic radiation to an
acceptable value. To study the electromagnetic radiation of the PFU, a PFU model has been established
based on Ansoft Maxwell. The solution type is transient. Eddy current effect and skin effect are taken into
consideration in simulation. A proper shielding measure is used to reduce the electromagnetic radiation based
on the simulation results. After manufacturing the PFU, measurement of electromagnetic radiation
experiments are carried out to verify the correctness of the simulation results. The results show that finite
element simulation can be effectively used in the design of the PFU.
References:
[1] E. Spahn, G. Buderer, and W. Wenning, “A compact pulse forming network, based on semiconducting
switches, for electric gun applications,” Magnetics, IEEE Transactions on, vol.35, no.1, pp.378-382, Jan 1999.
[2] Y.-S. Jin, H.-S. Lee, J.-S. Kim, Y.-B. Kim, and G.-H. Rim, “Compact 200 kJ pulse power system with a simple
crowbar circuit,” in Dig.14th Pulsed Power Conf. USA, 2003, pp.1239-1242.
[3] M. Shaoliang and L. Baoming, “Setup of pulsed power system for electro-thermal chemical launcher
research,” Trajectory Trans., vol. 16, p. 86, Mar. 2004, China.
[4] Y.-S. Jin, H.-S. Lee, J.-S. Kim, Y.-B. Kim, and G.-H. Rim, “Novle crowbar circuit for compact 50kJ capacitor
bank,” Plasma Science, IEEE Transactions on, vol.32, no.2, pp.525-530, April 2004.
[5] E. Spahn, V. Zorngiebel, K. Sterzelmeier, G. Buderer, and V. Brommer, “50 kJ ultra-compact pulsed
power supply unit for various applications,” in Dig. Eur. Conf. Power Electronics and Applications,
Germany, Sept. 2005, p.7.
[6] Weiqun Yuan; Ping Yan, "Simulation of the Eddy Current Effects on the Inductance Gradient of Railgun,"
Electromagnetic Launch Technology, 2008 14th Symposiu
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-20
On The Effect of Different Pulse Forming Networks (PFN) on Plasma
Produced From Guns of Various Geometry
G. Sahoo*1, R. Paikaray1 S. Samantaray 2, P.S. Das1, J. Ghosh3 and A. Sanyasi3
1) Ravenshaw University, Cuttack-753003, Odisha, India
2) Christ College, Cuttack-753001 Odisha, India
3) Institute for Plasma Research, Bhat, Gandhinagar- 382428, Gujarat, India
E mail: gourishankar.sahoo@gmail.com
Different pulse forming networks (PFN) such as LC, Guilemin A, B, C E type are designed
according to the gun and plasma parameters and the results are analyzed to establish a condition of
optimization for different geometry of guns[1]. Here different types of guns such as co-axial, gas
injected washer plasma gun having different geometry are designed and tested with the PFNs.
References:
[1] G. N. Glasoe and J. V. Lebacqz, Pulse Generators, McGraw Hill Book Company, New York 1948.
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-21
Quasi-square Wave Output Pulse Power Source Based on Electric Explosive
Opening Switch
FU Jiabin*, XIE Weiping, WU Youcheng and HAO Shirong
LAPA, Institute of Fluid Physics, CAEP, P.O.Box.919-108, Mianyang, Sichuan, 621900, China
Abstract: In order to improve the output waveform of the inductive energy storage pulse power
source, this paper presents a quasi-square wave output pulse power source based on electric explosive
opening switch (EEOS). This kind of pulse source uses a pulse capacitor as the initial energy storage, which
discharges to the EEOS through the pulse forming network (PFN). The EEOS switches off when the
discharge current nearly reaches the peak, thus the energy is switched to the load. Since the current in the
PFN’s inductors can not be mutated, the load voltage can amount to several times the charging voltage of
the storage capacitor. Due to the non-mutated voltages in the PFN’s capacitors, the load voltage can be
quasi-square. Parameters of the EEOS and the PFN are determined by theoretical analysis and circuit
simulation, which is verified by experimental results. With a 1F storage capacitor being charged to 32kV,
the voltage on the 10Ω load is obtained as 83kV in amplitude, 279ns in FWHM, and about 172ns in full
width at 90% magnitude, indicating that this kind of pulse power source is feasible.
Key words：Quasi-square wave; pulse power source; pulse forming network; electric explosive
opening switch
E-mail address : fujiabin23@163.com
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-22
Design of Underwater Electrical Wire Explosion Experimental Platform
Ruoyu Han*, Jiawei Wu*, Haibin Zhou, Youchuang Chao, Qiaojue Liu and Yan Jing
State key laboratory of electrical insulation for power equipment, Xi’an Jiaotong University,
Xi’an, 710049, China
Underwater electrical wire explosion (UEWE) is a complex process with a series of physical and
chemical phenomena, such as shock waves and light radiation fluxes [1], [2]. Some essays have
described the characteristics of shock waves. Other researches have investigated the plasma during the
process. Nevertheless, this process is so sophisticated that many details don’t have clear explanations. In
order to have a comprehensive study of UEWE, it is necessary to establish a test platform with a variety
of discharge parameters and diagnostic techniques. The purpose of this paper is to design a test platform,
aiming to select proper equipment and diagnostic methods for UEWE.
The test platform can be divided to four parts, impulse current source, load, chamber, and diagnostic
equipment. Impulse current source includes 50kV constant voltage power supply, 4 pulse capacitors
(each capacitor is 50kV, 6μF), three-electrode spark gap switch, resistors, and inductors. This source can
generate currents from several kiloampere to several hundred kiloampere by changing the charge voltage,
the load, and the number of capacitors, resistors, and inductors. The shortest risetime of the current is
~2μs by simulation. The load is made of electrodes and wire. The wire’s length varies from 1mm to
100mm. The wire’s diameter varies from 0.1mm to 1mm. The chamber is a stainless steel hollow cylinder with
diameter of 1200mm and height of 1000mm. The size of the chamber considers the safety factor under
impulse pressure and the reaction of shock wave which should not impact plasma channel. Diagnostic
equipment can be classified to three types, electrical parameters measurement, optical parameters
measurement, and pressure measurement. Two Rogowski coils are placed at both ends of the wire to
measure the load current while two resistance-capacitance voltage dividers measure the voltage drop of
the load. Shadow images, schlieren images, and interferometry images are recorded by framing camera and
streak camera to investigate the plasma channel. Besides, the chamber is filled by water and has six
couples of windows for optical observation. As for pressure measurement, two PCB138 probes are
used in this platform. Other details in experiment will be presented in the full paper. This paper also does
some simulations, helping design proper structures and mechanical parameters of the platform. The load
has a structure with low inductance (~100nH) and fine distribution of electric field. What’s more, this
structure must tolerate shock waves with peak pressure more than 100MPa. Another simulation is to
determine the thickness of quartz glass and chamber wall, which must be strong enough under shock waves.
The inductance and resistance of each component are also estimated to calculate the waveforms of current
and shock wave. Details will be presented in the full paper.
(a) Chamber
(b) Load
Fig.1 Design of some structure in the platform
References:
[1] Y. E. Krasik, A. Grinenko, A. Sayapin, et al., “Underwater electrical wire explosion and its applications”,
IEEE Transactions on Plasma Science, Vol. 36, pp. 423-434, 2008.
[2] A. Grinenko, A. Sayapin, V. Tz. Gurovich, et al., “Underwater electrical explosion of a Cu wire”,
Journal of Applied Physics, Vol. 97, pp. 023303:1-023303:6, 2005.
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-23
Operation Characteristics of 480 kJ Pulsed Power System for Disintegration of
Metallic Shaped-charge Jet
Yun Sik Jin*1, Chuhyun Cho1, Jong Soo Kim1, Dae Hwan Kwak2, Seok Han Yoon3,
In Su Koo3, Gwang Lyeon Kim4, Si Woo Kim5, Jae Hyun Joo5 and Jeong Tae Kim5
1)
2)
3)
4)
5)
Korea Electrotechnology Research Institute, Changwon 641-120, Korea
Korea University of Science and Technology
Hyundai Wia Corporation
Poongsan R&D Institute
Agency for Defense Development
A method for reducing the penetration power of shaped charges is to apply an intense current pulse through
the metallic shaped-charge jets (hereafter jet for brevity) [1-2]. Fast moving jet can be particulated or
fragmented by the electromagnetic action between an intense current pulse and metallic jet. A protective system
which utilizes the jet disruption principle by high current pulse consists of a capacitor bank and a pair of
electrode. For the experiments on the interaction of a high current pulse with jet, a 480 kJ capacitive pulsed
power system (PPS) was designed and fabricated. Twelve 40 kV, 40kJ capacitors are connected in parallel by
the wide bus bars. The PPS is charged to a desired voltage automatically by a fast capacitor charger and
charging control system. Multiple high voltage coaxial cables connected in parallel are used to transfer
capacitor bank energy to a pair of electrode. System parameters such as inductance and resistance of the jet
were analyzed through preliminary current flowing experiment.
References:
[1] Pollock, C. E., 1994, “Electromagnetic Effects on the Natural Hydrodynamic Instability of Stretching, High
Velocity Metallic Jets,” Proceedings of the Fourth Megagauss Magnetic Field Generation and Pulsed
Power Applications,Nova Science Publishers, New York
[2] M. Wickert, “Electric Armor Against Shaped Charges: Analysis of Jet Distortion With Respect to Jet
Dynamics and Current Flow”, IEEE Trans. Magn. Vol. 43, pp 426-429, No.1 2007
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-24
Analysis of Bubble Shape under High Repetitive Plasmas in Water
Hirohisa Yomura*1, Jyunpei Takeshita 1, Masahiro Akiyama1, Kichiro Yamamoto1, Takashi Sakugawa2
and Hidenori Akiyama2
Kagoshima University, Kagoshima 890-0065, Japan.
Kumamoto University, Kumamoto 860-8555, Japan
Recently, repetitive and reliable pulsed power generators using a magnetic pulse compression (MPC)
circuit [1] have been developed and used for water applications [2]. The pulsed power generator for our research
was operated under the following parameters: 500 pulses per second (pps); peak voltage 35 kV and current 10 A;
2.2 µs at full width at half maximum (FWHM); a copper electrode 0.8 mm in diameter; and water conductivity
of 170 µS/cm.
Our research is for analysis of bubble shape using high repetitive plasma in water. A single shot to 250
pps plasmas generated streamers shape, however, 500 pps plasmas changed to ball shape. Some small bubbles
gathered to tip of electrode.
Those phenomena were focused on changed pressure from water temperature. Pressure and water
temperature have the relationship which is vapor pressure curve. The over 100 degree Celsius has been fallen to
prenormal temperature, when pressure is changed to decrease.
References:
M. Akiyama, T. Sakugawa, S.Hamid R. Hosseini, E. Shiraishi, T. Kiyan and H. Akiyama, " High- Performance
Pulsed-Power Generator Controlled by FPGA”, IEEE Trans. on Plasma Sci., Vol. 38, pp. 2588-2592, 2010.
H. Akiyama, S. Katsuki and M. Akiyama；"Industrial Plasma Technology (Applications of Pulsed Power
and Plasmas to Bio Systems and Living Organisms)", Wiley-VCH Verlag GmbH & Co., pp.149-163, 2010.
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-25
Characteristics of Underwater Shock Wave Generated by High Current Short
Pulse Discharge
Hiroaki Ito* and Kosuke Miyata
Graduate School of Science and Engineering, University of Toyama, Toyama 930-8555, Japan
The subject of the generation of strong shock waves has been of continuous interest due to its important
potential applications in basic and applied research related to equations of state, plasma and space physics. In a
laboratory environment, there are several methods of shock wave generation, for instance, chemical explosions,
laser irradiation of a target, the Z-pinch approach, and underwater electrical explosions of wires. In the latter case,
underwater shock waves with several tens of megapascals were generated using moderate pulsed power generators
with stored energy of only several kilojoules. A high shock wave pressure in water is realized due to underwater
explosion of explosives (wire) and/or quick release of high current at the high voltage electric power in water. The
small compressibility of water and the relatively slight decay of a shock wave during its propagation make the shock
wave attractive for various practical applications like industry, medical and environmental applications.
In order to generate the underwater shock wave with ultra-high pressure and good controllability, we have
developed the underwater shock wave system with pulse power machine, which consists of a Marx generator and
a pulse forming line. We show the characteristics of the underwater shock wave generated by a high current short
pulse discharge. The pressure and the propagation mode of the underwater shock wave were measured by a
PolyVinylidene DiFluoride (PVDF) pressure transducer and laser shadowgraphic method, respectively. When the
Marx generator output voltage of 150 kV was applied to the electrode with the discharge gap distance of 10 mm,
the underwater shock wave with peak pressure of 313 MPa and average propagation velocity of 1750 m/s was
observed at 30 mm downstream from the electrode axis.
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-26
Dependence of Plasma Plume Formation on Applied Voltage Waveform in
Atmospheric Pressure Plasma
Kiyoyuki Yambe*1, Kohmei Konda1, Kazuo Ogura1 and Hajime Sakakita2
Graduate School of Science and Technology, Niigata University, Niigata 950-2181, Japan
National Institute of Advanced Industrial Science and Technology (AIST), Ibaraki 305-8568, Japan
Recently, plasma techniques under atmospheric pressure have been adopted for industrial, biological, and medical
applications. Atmospheric pressure plasma of dielectric barrier discharge is intermittently generated using a dielectric,
rare gas, and metal electrode by applying RF high voltage [1]. A quartz tube is used as a dielectric and plasma is
released into the atmosphere. Plasma irradiation is applied for material processing without thermal damage under
atmospheric pressure. A plasma plume is small bullet-like volume of plasma traveling at unusually high velocities.
The plasma density is an important factor to examine the mechanism of plasma generation in such atmospheric
pressure plasmas. In the development of industrial, biological, and medical applications, it is necessary to express the
values of the plasma current and plasma density for an effective plasma supplement for materials. The plasma density
is estimated from the plasma current, the plasma drift velocity, and the current cross-section. The plasma plume
current is estimated from the difference in currents on the circuit and the drift velocity is measured using a
photodetector [2]. In addition, the release of the plasma plume into the atmosphere is influenced by the gas flow
state [3] and the behavior of plasma plume is related to the hydrodynamic instability. The traveling of the luminous
bullet with the plasma light emission is coincident with the behavior of a positive streamer caused by
photoionization. The formation of plasma plume is related with the movement of the ionization front. The movement
of plasma plume is driven by the charge of plasma plume. The charge of plasma plume is estimated from the time
integral of the plasma plume current. The plasma plume current is influenced by the waveform of applied voltage.
It is necessary to examine experimentally the relation between plasma plume formation and applied voltage waveform.
In this study, we will describe the dependences of plasma plume
length and current on applied voltage waveform in atmospheric pressure
plasma using a quartz tube, helium gas, and copper foil electrodes by
applying RF high voltage. The applied voltage waveform is composed
of some positive and negative pulses. The applied voltage waveform
of large pulse with 2 positive and 1 negative at peak-to-peak voltage 18
kV is shown in Fig 1. The small pulses from 14 µs depend on circuit
resonance. The dependences of plasma plume length on the number
of large pulse at gas flow rate 2.0 slm are shown in Fig.
2. In the case of 1 large positive pulse, the plasma plume length
increases by increasing the large negative pulse. While, the length
at 3 large positive pulses hardly depends on the number of large negative
pulse. Consequently, the applied voltage waveform would be important
factor for plasma plume formation.
References:
X. Lu, G.V. Naidis, M. Laroussi, K. Ostrikov, Physics Prepoers, vol.
540, pp. 123-166, 2014.
K. Yambe, H. Saito, K. Ogura, Proceedings of IEEE Pulsed Power
and Plasma Science Conference, pp. 156- 160 San Francisco,
2013.
K. Yambe, T. Furuichi, K. Ogura, JPS Conf. Proc. vol. 1, pp.
015084_1-5, 2014
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-27
Effect of Dielectric Temperature on Plasma Plume in an Argon Atmospheric
Pressure Discharge
Jian Song*1, Jingfeng Tang2 and Daren Yu1
School of Energy Science and Engineering, Harbin Institute of Technology, Harbin, 150001, China
Academy of Fundamental and Interdisciplinary Sciences, Harbin Institute of Technology, Harbin, 150001, China
In recent years, APPJ (atmospheric pressure plasma jet) has attracted extensive attentions due to its wide
applications, such as surface etching, pollution control, sterilization, and DNA damage, [1-5] which all propose a
high requirement to the length and volume of plasma plume.
As an unnegligible factor of APPJ properties, the influence of temperature on APPJ is lacking in research.
In our experiment, some physics characteristics of APPJ versus dielectric temperature are analyzed with
different flow regime and peak voltage. It is found that the APPJ length and volume are clearly augmented,
the maximal increments of peak length and volume could reach 34% and 147% at 7 kV applied voltage,
respectively, and the transition regions show remarkable expansion with the heated dielectric at different
applied voltages. Through the study it indicates that different factors play a major role in the two boundaries of
transition region. The increase of radial and axial velocities is the dominant reason for the transition mode
extension to low velocity region, and the delay of transition mode is mostly attributed to the variety of
kinematic viscosity. A clear distinction is disclosed between two different dielectric temperatures. In room
temperature, the longest APPJ is proportional to the applied voltage, but it displays an opposite tendency in
high temperature. It may supply a feasible way to change plume length and volume in low applied voltage by
varying the dielectric temperature.
References:
M. Laroussi, Plasma Processes Polym. 2,391(2005).
F. Iza, J. K. Lee, and M. G. Kong, Phys. Rev. Lett. 99, 075004 (2007).
J. L. Walsh and M. G. Kong, Appl. Phys. Lett. 93, 111501 (2008).
J. Kolb and A. Mohamed, Appl. Phys. Lett. 92, 241501 (2008).
X. Han and M. Klas, Appl. Phys. Lett. 102, 233703 (2013).
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-28
Effect of Magnets on Nanosecond Volume Discharges
Liqiu Wei*, Jingfeng Tang, Desheng Zhou and Chaohai Zhang
Harbin Institute of Technology, Harbin 150001, China
Volume discharge excited by repetitive nanosecond pulse has been proposed, which have been widely used
in waste gas, synthesis of nanostructured material, and so on [1]. Magnets effect has been investigated on low
pressure discharges[2]. In this study, we are focus on the influence of strong magnetic field for the nanosecond
volume discharge under atmospheric pressure.
The experimental system includes a nanosecond pulse generator, discharge system, and a measurement system.
The upper electrode was anode and the lower one was cathode. The two electrodes were composed of stainless
steel plates with the sizes of 10mm*20mm and a thickness of 2mm, the plate-plate electrodes separated by a
6-mm vertical distance, the two dielectrics were made of mica with a thickness of 1 mm and a permittivity
εr= 6. By adjusting the distance between the magnetic poles and the power supply current, the maximum magnetic
is 2T. the magnetic field is perpendicular to the electric field .A high voltage probe (Tektronix P6015A) and
a Rogowski coil were used to measure the voltage and current. The discharge signals and images were
recorded by Tektronix DPO2024 and SONY digital camera.
As observed, with a excited voltage of 30kV，when the magnetic field strength is 0T, the discharge is
filament and inhomogeneous in a large volume. By change the magnetic field to 1.2T in the overall discharge
region, the diffuse and homogeneous occurred, the brightness enhanced significantly. The peak of discharge
current increased.
Avalanche effect is the main mechanism of the DBD, under the influence of magnetic force, particle motion
were constrained, which could lead to the reduction of collision frequency, the discharge channel were easier to
build. Besides, it also play a catalysis role in the accumulated charge on the surface of the dielectric board ,
which was favorable for development of the discharge.
References:
J.f. Tang, TRANSACTIONS ON PLASMA SCIENCE, VOL.42, NO.3, MARCH 2014
C. Enloe, G. Font, T. McLaughlin, and D. Orlov, AIAA J. 46, 2730–2740 (2008).
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-29
Gas Heating and Streamer-To-Leader Transition of Impulse Surface Discharge on
Quartz Glass in Atmospheric Air
Ryo Sasamoto*1, Yoichi Inada2, Takao Matsumoto1, Yasuji Izawa1 and Kiyoto Nishijima1
1)
2)
Department of electrical engineering, Fukuoka University, Fukuoka 814-0180, Japan
Graduate School of Electrical Engineering, Fukuoka University, Fukuoka 814-0180, Japan
Flashover on the surface of dielectric material gives extensive damage to the insulation system,
resulting in reduced withstand voltage and system downtime as the damaged component is located and replaced.
Therefore, the flashover on dielectrics has been studied for many years with the object of finding ways to
reduce its incidence. Especially, streamer-to-leader transition process is still the object of intensive experimental
and theoretical studies. In the case of long-gap gaseous discharge, there is a proposed explanation that the
transition-to-leader is occurred due to the joule heating of streamer channel [1]. While, there is no compelling
explanation in the case of surface discharge.
In this work, the gas temperature of surface streamer on insulation material was measured using
spectroscopic method in atmospheric air. In the experiment, a quarts glass that is extremely thinly- coated by
conductive indium tin oxide (ITO) on one side was used as a dielectric material having back electrode. The ITO
coating is thin enough for near-ultraviolet light to penetrate. A torus-shape stainless plate having 60 mm
inner diameter was placed on the quartz glass as a ground electrode. A needle electrode was vertically set on
the quartz electrode at the center of the ground electrode. Positive impulse voltage having a rise time of
about 15 nano-seconds and a full width at half maximum of 3.0 micro-seconds was applied to the needle
electrode. The peak of applied impulse voltage was approximately 18 kV. The discharge light emission was
observed using an ICCD camera (Ander, iStar). In addition, spectroscopic measurement system composed of an
ICCD camera (Andor, iStar) and a spectrometer (Solar tii, ms7504i) acquired the light emission spectrum of
surface discharge. The gas temperature of surface streamer around the tip of needle electrode was derived by fits
of numerically calculated rotational spectra of N2 second system band (0-0) to experimentally measured one.
References:
[1] E M Bazelyan, Yu P Raizer and N L Aleksandrov, “The effect of reduced air density on streamer- to-leader
transition and on properties of long positive leader”, J. Phys. D: Appl. Phys. Vol. 40 4133-4144, 2007.
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-30
HiPIMS Glow Plasma by Magnetic Field Modification
Takumi Konishi*1, Koichi Takaki1 and Ken Yukimura2
Department of Electrical and Electronic Engineering, Iwate University, Iwate 020-8551, Japan
Department of Electrical and Electronic Engineering, Iwate University, and also with the Nanoelectronics Research
Institute, National Institute of Advanced Industrial Science and Technol ogy-Tsukuba Central
High-power impulse magnetron sputtering (HiPIMS) is an
emerging sputtering technique of physical vapor deposition,
14
-2
where the plasma density is on the order of 10 cm with a
2
power density of 1 kW/cm or greater. There are influencing
parameters for plasma production-zone; that is, the discharge
current, the source voltage and the magnetic flux density. The
magnetic flux density determines the plasma production-zone.
This paper describes the effect of magnetic field configuration
on the distribution and the power consumption of the HiPIMS
glow plasma.
The magnet arrangement was configured, as shown in
Fig.1(a) for n = 1 inner magnet, and Fig.1(b), and 1(c) for n = 3
and n = 7 inner magnets, respectively. By varying n up to 7,
both the magnetic flux density on the target and its distribution
were altered. Thus, the location of the plasma production was
intended so as to be controlled by changing the number of
the inner magnet in the concentric magnet arrangement.
Fig.2 shows spatial distributions of the plasma as a
function of the radial distance, which is obtained from the
intensity of optical emission spectrometry spectrum of argon
ions at a wavelength of about 434 nm. The peak position of
the light-emission intensity becomes greater from 27 to 36 mm
from the center of the target with increasing the number of the
inner magnets. The increase in the number of the inner magnets
lowers the arc transition voltage [1]. The power consumed in
the plasma at the threshold voltage of the glow-to-arc transition
also decreases with the increased n. Hence a higher source
voltage can be applied to the target in the case at smaller number
of the inner magnets and the highest glow voltage with the
highest power consumption can be obtained at n = 1 under the
present condition.
References:
K. Yukimura, H. Ogiso, S. Nakano, and K. Takaki, “Carbon
ion production using a high-power impulse magnetron
sputtering glow plasma,” IEEE Trans. Plasma Sci., vol. 41,
no. 10, pp. 3012–3020, Oct. 2013..
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-31
Influence of Solenoidal Magnetic Field on Laser Ablation Plasma
S.Ikeda *1,2, K. Kato2, J. Hasegawa, M. Nakajima1, M. Okamura3 and K. Horioka1
Tokyo institute of technology, Yokohama 226-8503, Japan
RIKEN, Saitama 351-0198, Japan
Brookhaven National Laboratory, NY 11973, USA
Laser ablation can produce large amounts of ions. The ablation plasma may obtain high drift speed and
low temperature due to an expansion. Therefore, the plasma is expected to be a high flux pulsed ion source. In
typical setup of laser ion source, the plasma spreads three dimensionally in the absence of external forces and
then is injected to an extractor away from the target. This means that most of the ions are not extracted and the
density distribution is not controlled or optimized for the extraction. A solenoidal magnetic field is expected to
be used to control the spread of the plasma like magnetic nozzle[1] or collective focusing effect[2]. We
discuss the interaction of the magnetic field and the drifting plasma to estimate the possibility of the control.
The interaction depends on the density and the magnetic flux density. If the density is low, the diamagnetic
azimuthal current is determined by the angular momentum conservation and the ions motion is also determined
by the Lorentz force. On the other hand, if the density is high, the diamagnetic current depends on the conductivity
and the plasma is confined by the pressure of the distorted magnetic field. In addition, the magnetic field
penetrates into the plasma. The density of the laser ablation plasma is largely different by the space and time. So,
we try to clarify the dependency of the interaction on the density experimentally.
We inject the laser ablation plasma into a solenoidal magnetic field and measure the plasma flux with
the changing distance from a target to the solenoid. The laser intensity also change from 108 to
9
2
10 W/cm . We use a device like fig.1. The density in the solenoid depends on the distance and the
intensity. We discuss the magnetic nozzle, collective focusing effect, and the transition between the two
mechanisms.
fig 1. Experimental setup
References:
E. Ahedo, M. Merino, Phys. Plasma, 17, 073501, 2010
S. Robertson, Phys. Fluids, 26, 4, 1983
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-32
Matching a Nanosecond Pulse Source to a Streamer Corona Plasma with a
DC Bias
T. Huiskamp*1, N. Takamura2, T. Namihira3 and A. J. M. Pemen1
Electrical Energy Systems, Eindhoven University of Technology, Eindhoven, The Netherlands
Graduate School of Science and Technology, Kumamoto University, Kumamoto
Institute of Pulsed Power Science, Kumamoto University, Kumamoto
Matching a pulse source to a plasma load is one of the main challenges to overcome in order to maximize
the full potential of pulsed discharges for air purification applications [1]. In this paper we propose experiments
which investigate the matching of a nanosecond pulse source to a corona plasma reactor which is aided by a high
voltage on a tertiary electrode. The corona plasma reactor is a wire- cylinder reactor as is commonly used in pulsed
power plasmas. A tertiary electrode is situated on a dielectric layer against the cylinder of the reactor. On this
tertiary electrode we can apply a pulsed, RF or DC voltage to provide an additional plasma and bias voltage in
the corona plasma reactor. The pulse source that energizes the main corona plasma is the nanosecond pulse source
of the Kumamoto University, Japan [2]. In this contribution we show results of experiments with a DC voltage on
the tertiary electrode. We varied the amplitude of the pulsed voltage, as well as the DC voltage and investigated
their effect on the corona plasma with energy and ozone measurements. The results show that the matching to the
reactor increases with increasing DC voltages. However, the matching effect decreases with higher repetition rates.
Furthermore, ozone measurements confirmed that a better matching also results in a higher ozone production.
References
G. J. J. Winands, Z. Liu, E. J. M. v. Heesch, A. J. M. Pemen and K. Yan “Matching a Pulsed- Power Modulator to a
Streamer Plasma Reactor”, Plasma Science, IEEE Transactions on, vol. 36, no 1, pp. 243-252, 2008.
D. Wang, S. Okoda, T. Matsumoto, T. Namihira and H. Akiyama “Pulsed Discharge by Nanosecond Pulsed
Power in Atmospheric Air”, Plasma Science, IEEE Transactions on, vol. 38, no 10, pp. 2746-2751, 2010.
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-33
Measuring Streamer Head Velocity, Diameter and Number Based on
Characteristic Impedance of Pulsed Power Generator in Ambient Air
Takafumi Okuyama*1, Yasuhiro Maruta1, Douyan Wang2, Takao Namihira3 and Hidenori Akiyama3
Graduate School of Science and Technology, Kumamoto University, Kumamoto 860-8555, Japan
Priority Organization for Innovation and Excellence, Kumamoto University, Kumamoto 860-8555, Japan
Institute of Pulsed Power Science, Kumamoto University, Kumamoto 860-8555, Japan
To present, due to difficulties in varying discharge current during the streamer discharge phase, studies of
streamer discharge have only explored limited parameter regimes such as applied voltage and voltage rise time
[1, 2], leaving large research areas unexplored. Characteristic impedance of pulsed power generators has
heretofore not been taken up very much. However, when characteristic impedance of a pulsed power generator
decreases, discharge current increases, implying that it is an important parameter for streamer discharge application.
In this research, we observed the propagation process of streamer heads based on characteristic impedance of pulsed
power generator. To decrease characteristic impedance, 900 Ω pulsed power generators were connected in parallel.
The maximum parallel connection was three, and characteristic impedance of pulsed power generators were varied
from 900 Ω, 450 Ω and 300 Ω. Charging voltage to pulsed power generator was fixed at 18 kV. The velocity,
diameter and the number of streamer heads in ambient air were investigated using an ICCD camera; the time history
of each parameter was also investigated. We observed streamer discharge in a coaxial electrode with an inner diameter
of 0.5 mm, outer diameter of 60 mm, and length of 10 mm. The results show that, as characteristic impedance of
pulsed power generator decreases from 900 Ω to 300 Ω, six phenomena occur: voltage rise time rapidly rises
from 58 to 27.8 ns; applied voltage increases from 63.8 to 89.6 kV; discharge current increases at phase of
streamer discharge; streamer head propagation begins earlier; streamer head velocity increases from 0.88 to 1.4
-1
mm ns ; and streamer head diameter increases. This streamer head diameter increase over time shows a tendency to
increase from 2.3 to 3.7 mm at 300 Ω and a tendency to decrease from 3.4 to 1.9 mm at 900 Ω. The number of
streamer heads tends to increase over time except at 900 Ω, when it drops after about 23 ns. In addition, when the
propagation distance from the inner electrode is approximately 25 mm, the number of streamer heads increases
most at 450 Ω.
References:
T M P Bries, J Kos, G J J Winands, E M van Veldhuizen and U Ebert, “Positive and negative streamers in ambient
air: measuring diameter, velocity and dissipated energy”, Journal of Physics D: Applied Physics, Vol.41,
234004, 2008
Atushi Komuro, Ryo Ono and Tetsuji Oda, “Effects of pulse voltage rise rate on velocity, diameter and radical
production of an atmospheric-pressure streamer discharge”, Plasma Sources Science and Technology, Vol.22,
045002, 2013
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-34
Metal and Metal Oxide Nanoparticles Synthesis by Pulsed Plasma in Liquid
Zhazgul Kelgenbaeva* and Tsutomu Mashimo
Graduate School of Science and Technology, Kumamoto University, Kumamoto 860-8555, Japan
Institute of Pulsed Power Science, Kumamoto University, Kumamoto 860-8555, Japan
E-mail: 111d9109@st.kumamoto-u.ac.jp
Recently tremendous interest has been generated in the study of metal\metal oxides nanoparticles because
they lead to a new generation of optics, electronics, sensors and photocatalysis [1]. In particular, methods for the
preparation of tin (Sn) and indium (In) nanoparticles have been frequently proposed in recent years because of
their novel physicochemical (optical and catalytic) properties. Here, we present tin and indium nanoparticles
less than 10 nm in size, synthesized by the pulsed plasma in liquid method. Pulsed plasma in liquid is based
on the arc discharge [2] and is a good alternative to other methods to synthesize various size-shape controlled
nanomaterials; this process is relatively cheap and environmentally friendly. The schematic of the experimental
setup is shown in Figure. The liquids used in this study, H2O and H2O2, not only act as a media, but also affects
on the sizes and phase compositions of nanoparticles. Pure Sn nanoparticles were synthesized both in H2O and
H2O2, while pure In nanoparticles were synthesized in H2O and a mixture of In with In2O3 in H2O2. The tetragonal
Sn and In nanoparticles showed good crystallinity (by X-Ray diffraction) with spherical shape and average diameter
of 3-4 nm for Sn, and 4.5-6.0 nm for In (by High-resolution TEM). Thermogravimetrical (TGA) analysis indicated
the thermal stability of synthesized Sn and In nanoparticles. Differential scanning calorimeter (DSC) measurements
revealed a decrease in the melting temperature up to 225°C for Sn and 152°C for In, which are smaller than
those for bulk materials by 2.5 %. Further, by annealing these metal (Sn, In) nanoparticles synthesized by pulsed
plasma in liquid, we obtained SnO2 (at 700°C) and In2O3 (400°C) nanoparticles. Their physicochemical properties
have been also studied.
Experimental setup for Pulsed Plasma in Liquid
References:
M. Kanehara, H. Koike, T. Yoshinaga, and T. Teranishi, “Indium tin oxide nanoparticles with compositionally
tunable surface Plasmon resonance frequencies in the near-IR region”, J. Am. Chem. Sos. 2009, 131, 17736-37.
E. Omurzak, J. Jasnakunov, N. Mairykova et al.”Synthesis method of nanomaterials by pulsed plasma in liquid”,
J Nanosci Nanotech. 2007, 7, 3157-59
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-35
Observation of Water Surface Discharge Emission Spectrum by Timeresolved Spectroscopy
H. Nagaoka, K. Yoshihara*, T. Hori, H. Hosseini, T. Sakugawa and H. Akiyama.
Graduate school of science and Technology, Kumamoto University, 2-39-1, Kurokami, Chuo-ku, Kumamoto,8608555, Japan
Pulsed discharge plasma in water produces many kind of by-products such as shockwaves, UV light, active
species and reactive radicals, and thus has recently been studied for industrial, environmental and biomedical
applications [1]. When a discharge occurs, various chemically active species are generated, including transient
species (OH·, NO2·, NO radicals) and long-lived chemical products (O3,H2O2, NO−3 , NO−2 ) [2]. Among these
chemically active species, OH radicals, which have the highest oxidation potential, play an important role for
applications. However, direct measurement of OH radicals is difficult due to their short lifetime.
In this study, water surface discharges were measured by time-resolved spectroscopy, which is able to
measure emission spectrum in nanosecond-order, to detect OH radicals directly. Effects of solution conductivity,
atmospheric gas, and measurement range from the tip of electrode to the edge of the streamer were also investigated.
References:
[1] Hidenori Akiyama, Shunsuke Sakai, Takashi Sakugawa and Takao Namihira ”Environmental Applications of
Repetitive Pulsed Power”, IEEE Transactions on dielectrics and Electrical Insulation Vol. 14, No 4; August 2007
[2] P. Lukes, E. Dolezalova, I.Sisrova and M. Clupek “Aqueous-phase chemistry and bactericidal effects from an air
discharge plasma in contact with water: evidence for the formation of peroxynitrite through a pseudo-secondorder post-discharge reaction of H2O2 and HNO2”, Plasma Sources Sci. Technol. 23 (2014) 015019 (15pp).
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-36
Radical Distribution on Radial Direction of Atmospheric-pressure Helium
Plasma Jet
Norimitsu Takamura*1, Kohei Umeda1, Taishi Matsuoka2, Douyan Wang3, Takao Namihira4 and
Hidenori Akiyama4
Graduate School of Science and Technology, Kumamoto University,
The Department of Computer Science and Electrical Engineering, Kumamoto University,
Priority Organization for Innovation and Excellence, Kumamoto University,
Institute of Pulsed Power Science, Kumamoto University, Kumamoto 860-8555, Japan
Recently, various types of atmospheric-pressure plasma jets (APPJs) have been studied [1-4] and used in
particular for material processing [6-7] and biomedical applications [8-9] because they have a unique capability of
generating abundant chemical species under low temperature. Once APPJs are ejected into ambient air, their
emission spectra are known to be dominated by N2+ first negative system (FNS, B2∑u+ - X2∑g+, 391.4 nm)
and N2 second positive system (SPS, C3∏u-B3∏g), 337.1 nm) [2], [3], [4]. In addition, the emission spectra from O
(777 nm) and OH (309 nm) radicals, which are considered to play an important role in the processing of a
variety of materials and biomedical applications, have also been observed by spectroscopic measurement [3]. A
number of papers related to these radicals distribution on their travelling direction have been published [2], [4].
However, the radial distribution of these radicals remains unknown. In this study, therefore, we investigated
radical distribution by optical emission spectroscopy (OES) using an intensified charge-coupled device (ICCD)
camera and a spectroscope. Detailed experimental results will be shown at the conference.
References:
M. Teschke, J. Kedzierski, E. G. Finantu-Dinu, D. Korzec, and J. Engemann, “High-speed photographs of a
dielectric barrier atmospheric pressure plasma jet,” IEEE Trans. Plasma Sci., Vol.33, No. 2, pp. 310-311, 2005.
B. L. Sands, B. N. Ganguly, and K. Tachibana, “A streamer-like atmospheric pressure plasma jet,”
Appl. Phys. Lett., Vol. 92, p. 151503, 2008.
W. C. Zhu, Q. Li, X. M. Zhu, and Y. K. Pu, “Characteristics of atmospheric pressure plasma jets emerging into
ambient air and helium,” J. Appl. Phys. D: Appl. Phys., Vol. 42, p. 202002, 2009.
A. Begum, M. Laroussi, and M. R. Pervez “Atmospheric pressure He-air plasma jet: Breakdown process and
propagation phenomenon,” AIP Advances., Vol. 3, p. 062117, 2013.
Y. S. Seo, A. A. H. Mohamed, K. C. Woo, H. W. Lee, J. K. Lee, and K. T. Kim, “Comparative studies of
atmospheric pressure plasma characteristics between He and Ar working gases for sterilization,” IEEE Trans.
Plasma Sci., Vol.38, No. 10, pp. 2954-2962, 2010.
S. Kanazawa, T. Iwao, S. Akamine, and R. Ichiki, “Improving single-chamber solid oxide fuel cell performance by
plasma treatment using an atmospheric-pressure helium plasma jet,” Jpn. J. Appl. Phys., Vol. 50, p. 08KA04,
2011.
K. Kim, G. Kim, Y. Oh, T. G. Park, D. C. Han, and S. S. Yang, “Simple atmospheric-pressure nonthermal plasmajet system for poly(dimethylsiloxane) bonding process,” Jpn. J. Appl. Phys., Vol. 51, p. 06FL15, 2012.
T. Nakajima, H. Yasuda, H. Kurita, K. Takashima, and A. Mizuno, “Generation of bactericidal factors in the
liquid phase and approach to new gene transfer technology by low temperature plasma jet treatment,” I. J.
PEST., Vol. 5, No. 1, pp. 42-49, 2011.
N. Takamura, D. Wang, D. Seki, T. Namihira, K. Tano, H. Saitoh, and H. Akiyama, “Protein Transduction into
Eukaryotic Cells using Non-thermal Plasma,” I. J. PEST., Vol. 6, No. 1, pp. 59- 62, 2012.
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-37
The Study of Bubbles after Electrical Discharges in Liquids
Jyunpei Takeshita*1, Masahiro Akiyama1, Kichiro Yamamoto1, Sebastian Gnapowski2, S. Hamid R.
Hosseini2 and Hidenori Akiyama2
Kagoshima University, Kagoshima 890-0065, Japan.
Kumamoto University, Kumamoto 860-8555, Japan
Electrical Discharges in Liquids have been used in any applications such as the cleaning of dam waters [1],
bacterial decontamination of water [2] and so on. However, some generation processes of electrical discharges in
liquids have not been shown detail flow.
The present work aims to study of bubbles generated by electrical discharges in liquids using photographs.
Those photographs were taken by high speed camera (Nac Image Technology, INC.) and shadowgraph method. A
pulsed power generator generated pulsed power with a maximum output of 40 J/pulse which was applied to an
electrode of 0.8 mm in diameter. The liquid containing reactor vessel was made of acrylic resin and was 30x30x30
cm. The main target of this work was the analysis of bubble pulse which is kind of phenomena before disappeared
bubbles. Several times bubbles were repeated to expansion and contraction.
References:
S. Gnapowski, H. Akiyama, T. Sakugawa, and M. Akiyama, “Effects of Pulsed Power Discharges in Water on
Algae Treatment,” IEEJ Trans. Fundamentals and Materials, vol. 133, pp. 198-204, 2013.
A. Abou-Ghazale, S. Katsuki, K. H. Schoenbach, F. C. Dobbs, and K. R. Moreira, “Bacterial Decontamination of
Water by Means of Pulsed-Corona Discharges,” IEEE Trans. Plasma Science, vol. 30, pp. 1449-1453, 2002.
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-38
Time History of Pulsed Discharge in Coaxial Electrode
Y. Maruta*1, T. Okuyama1, D. Wang2, T. Namihira3 and H. Akiyama3
Graduate School of Science and Technology, Kumamoto University, Kumamoto 860-8555, Japan
Priority Organization for Innovation and Excellence, Kumamoto University, Japan
Institute of Pulsed Power Science, Kumamoto University, Japan
Pulsed discharge in coaxial electrode is mainly divided into three phases: a streamer discharge phase, which
has propagation of streamer heads with very higher energetic electron; and a glow discharge phase, which forms
between electrodes uniformly. Finally, the pulse discharge shifts to arc discharge phase. Streamer discharge
phenomena were well known by observation using high-speed camera or theoretical works using discharge
models [1, 2]. However, the analysis or researches which were focused in a discharge transitions from streamer
to glow and from glow to arc were not still reported so much. This works observes the transition process during
the pulsed discharge in a coaxial electrode using the high-speed digital framing camera.
In the experiment, pulse generator consists of a Blumlein line and a pulse transformer. Blumlein line has 400
ns of pulsed duration. A coaxial type electrode has inner 0.5 mm diameter, 60 mm of outer diameter and 10 mm
of length. The feeding gas into the coaxial electrode was synthetic air (N2:79%, O2:21%). The ultra high-speed
camera used to observe behavior of pulsed discharge enable to obtain continuous 8 images in single discharge.
The exposure time was fixed at 10 ns. The camera observed from onset of applied voltage to discharge
transition to arc discharge. After some streamer heads reached at outer electrode, twenty or more plasma
channels were made by the propagation of secondary streamer heads between electrodes. At that time, the
electrode is filled with discharge plasma and many photoionizations are caused by emission from discharge
plasma. This phenomenon is called as glow discharge. Concurrently, the discharge current increases in some plasma
channels and it decreases in other channels. Lastly, the emission intensity of one of plasma channel become very
strong and other channels gradually disappear. The selection of channel into arc discharge is ignited by fully
development of all streamer heads between electrodes and is caused by instability of plasma channel.
References:
T M P Briels, E M van Veldhuizen and U Ebert, “Positive streamers in air and nitrogen of varying density:
experiments on similarity laws” , Journal of Physics D: Applied physics, Volume 41, Number 23, 234008
Atsushi Komuro, Ryo Ono, Tetsuji Oda, “Two-dimensional simulation of streamer discharge including the
vibrationally excited molecules effects” Journal of Physics D:Applied Physics, Volume 45, Number 26, 2012
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-39
Inspection of the Effectiveness of the Thunderbolt Prevention System Using a
3D Printing Topography Model
Kotaro Omote* and F. Tanaka
Ishikawa National College of Technology, Ishikawa 929-0392, Japan
Wind-generated electricity has attracted attention as one of the most efficient renewable energy, while it
has not become widespread because it is not easy to find the installation sites and the maintenance cost is high.
According to the report of the NEDO, one of the main causes of wind-power generator accidents includes
lightning strikes.[1] Although the measures have been taken to prevent thunderbolts, the equipment still continues
to be damaged in Hokuriku District. This study investigates a protection technology from thunderbolts for a
feasible wind-power generator at low cost. In this paper, the effectiveness of the thunderbolt prevention system
using a topography model which made with 3D printing is inspected. The subject of investigation is the wind-power
generator in the Uchinada district of Ishikawa, which has a lightning rod and about which observation data has
been reported.[2] The experiment applies the voltage produced by the Marx generator to the topography model,
changing the height position of the high voltage electrode of the Marx generator. In this way, the present study
grasps the tendency of this system and acquires the data to conduct field investigation.
References:
New Energy and Industrial Technology Development Organization, “Wind Power Guideline for Japan” 2008, In
Japanese
Masayuki Minowa, Hitoshi Sakurano, Takashi Watanabe，Yoshiyuki Kubouchi, Masayuki Yoda, ”Observation
of Lightning Current at Uchinada Wind Power Station in Winter of 2011” Bulletin of Aichi Institute of
Technology, Vol. 48, pp143-147, 2013, In Japanese
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-40
Skin Effect Suppression in Sample Structure for Warm Dense Matter
Generated by Fast Pulsed-power Discharge with Isochoric Heating
Arata Watabe*, Kazumasa Takahashi, Toru Sasaki, Takashi Kikuchi and Nob. Harada
Nagaoka University of Technology,1603-1 Kamitomioka, Nagaoka 940-2188 , Japan
To evaluate properties of warm dense matter (WDM), a generation method using a pulsed- power discharge
with isochoric heating has been proposed [1,2]. The evaluation of WDM requires uniform heating in sample plasma,
and the sample size and the pulse frequency should be considered to neglect the skin effect. In previous study,
to prevent the skin effect in the sample, we have used a foamed metal for the pulsed-power discharge with
isochoric heating. In the case of fast pulsed-power generator [3], the uniformity of energy input should be considered,
because the skin depth decreases. In this study, the reduction method of the skin effect in pulsed- power discharge
with isochoric heating to perform uniform heating was investigated.
The skin effect as a function of frequency was measured with an alternating magnetic flux into the sample [1].
Evaluated samples were copper rod, foam, and foil, and were packed into the cylindrical vessel having 5 mm in
diameter. The copper foam was separated by 2 or 4 parts for the radial direction. The copper foil was also separated
from 50 mm (without separation) to 5 mm. The mass of copper foam and foil is set to be 0.1 g and 0.5 g.
Figure 1 shows the induced voltages normalized by one for air core as a function of frequency. The skin depth
at the frequency of 1 kHz corresponds to the radius of the copper rod. The skin effect for metal foam is neglected
under 100 kHz. The separated copper foams suppress the skin effect compared to the unseparated one. In the case
of copper foil, the skin effect is also suppressed as a function of separation width. From the comparison of
the skin effect for the copper foam and the copper foil, the separated copper foil is possible to suppress the skin
effect. The results indicate that uniform WDM generation of metallic sample with fast pulsed-power generator is
valid by using the separated foil.
Ai
Ai
Fig.1 Induced voltages normalized as a function of frequency for (a) foam and (b) foil
References:
Y. Miki, H. Saito, T. Takahashi, T. Sasaki, T. Kikuchi, and Nob. Harada, Nucl. Instrum. Methods Phys. Res. A, 733,
pp. 8–11, 2014.
Y. Amano, Y. Miki, T. Takahashi, T. Sasaki, T. Kikuchi, and Nob Harada, Rev. Sci. Instrum., 83, 085107, 2012.
R. Hayashi, F. Tamura, T. Kudo, K. Takahashi, T. Sasaki, T. Kikuchi, T. Aso, N. Harada, W. Jiang, K. Kashine, and
A. Tokuchi, ICOPS/BEAMS 2014 1P-3
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-41
Effect of Addition of Hydrogen Peroxide on Surfactant Treatment Using
Nanosecond Pulsed Powers
Mitsuru Morimoto*1, Kai Shimizu2, Toshiki Ninomiya1, Kenji Teranishi3 and Naoyuki Shimomura3
Graduate School of Advanced Technology and Science, The University of Tokushima, Tokushima, Japan
Department of Electrical and Electronic Engineering, The University of Tokushima, Tokushima, Japan
Institute of Technology and Science, The University of Tokushima, Tokushima, Japan
The water pollution has been one of environment issues. The treatment technique for contaminated water has
to be developed. Advanced oxidation processes (AOPs) as one of technologies treating wastewater have been
studied. However, in typical system for AOPs using ozone, energy consumption is large because efficiency of the
ozone production is not high. To generate ozone and treat waste water more efficiently, the technology using
pulsed power system has been studied [1-3]. The water treatment by nanosecond pulsed power utilizes not only
radicals [4] but also other actions of discharges. A water treatment system is developed to increase radical density
and as discharges could affect wastewater strongly. To realize the features, a dielectric barrier in electrodes was
adopted for the system to decrease electrode-separation in the reactor in addition to use of nanosecond pulsed powers.
In each country, consumption of surfactants in organic solvents has increased for domestic and industrial
usages because environmental load of surfactants is the smaller in organic solvents. However, a large amount of
surfactants are used home and industrially and is ejected. Then, a surfactant as a processing object was chosen for
the pulsed power treatment. In this study, the effect of addition of hydrogen peroxide in a surfactant water solution
was investigated. The foaming property of solution, as a behavior of surfactants, with hydrogen peroxide
disappeared faster than that of surfactant solution without it, for the pulsed power treatment. The reason for
reduction of foaming property would be degradations of ether linkage between hydrophilic group and hydrophobic
group in the surfactant. On the other hand, the CODMn of solution with hydrogen peroxide increased before the
treatment. Substances produced with the degradation might react with potassium permanganate used in the
measuring process of CODMn. In addition, hydrogen peroxide is one of substances reacted with measurement of
CODMn. In using pulsed power, electric discharges acted the surfactant solution and hydroxyl radicals would be
produced efficiently. Moreover, by addition of hydrogen peroxide to aqueous solutions, ozone and active species
such as hydroxyl radicals are generated more efficiently by electric discharges of pulsed power system than treatment
without hydrogen peroxide.
References:
M. Morimoto, K. Kusunoki, H. Nakai, K. Teranishi, N. Shimomura, " Development of Water Treatment System
Using Nanosecond Pulsed Powers to Treat Surfactant, " PPPS2013, 2013
H. Akiyama, S. Katsuki, T. Namihara, K. Ishibashi and N. Kiyosaki, "Cleaning of Lakes and Marshes by Pulsed
Power Produced Streamer Discharges in Water," J. Plasama Fusiom Res., vol. 79, (no. 1), pp. 26-30, 2003
Y. Minamitani and Y.Higashiyama, "Treatment of Waste Water by Pulsed Power Discharge," J. Inst. Electrostat.
Jpn., vol. 27, (no. 3), pp. 123-128, 2003
F. Fukawa, N. Shimomura, T. Yano, S. Yamanaka, K. Teranishi and H. Akiyama, "Application of Nanosecond
Pulsed Power to ozone Production by Streamer Corona," IEEE Trans. Plasma Sci., vol. 36, (no. 5), pp. 25922597, 2008
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-42
Pilot Scale Continuous Pulsed Electric Field Treatment of Liquid Products
J.C. Brion
EUROPULSE, route de Gignac, 46600 Cressensac, France
This paper presents a repetitive pulsed electric field (PEF) generator used for the continuous treatment of liquid
products [1]. This system uses a specific pressurized spark gap switching technology (dry air) with high repetitive
rate, connected to a pulse forming network consisting of a coaxial cable and lumped elements.
This equipment, including a 2 kW high voltage charger capacitors power supply and an interactive computer
control developed with Labview software, generates square waveform pulses. It is designed to allow a widely
adjustable operating pulse width (50, 100, 250, 500, 1000, 2000, 3000 ns), electric field strength (from 30 up to
80 kV/cm), pulse frequency (from 1 up to 815 Hz) and to produce a volumetric flow rate (from 1 up to 10 l/h).
Electrical considerations taken into account to design the pilot scale and some results are presented.
References:
J. Korolczuk, J. Rippoll Mc Keag, J. Carballeira Fernandez, F. Baron, N. Grosset, R. Jeantet, “Effect of pulsed
electric field processing parameters on Salmonella Enteritidis inactivation”, Journal of Food Engineering, Vol.
75, pp. 11-20, 2006.
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-43
Spatial and Temporal Ozone Distribution in Coaxial Reactor During Repetitive
Nano-Seconds Pulsed Discharge Processing
Kengo Fukunaga*1, Akihiko Ogasawara1, Han Junkai1, Douyan Wang2, Takao Namihira3 and Hidenori
Akiyama3
Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Chuo-ku, Kumamoto 8608555, Japan
Priority organization for Innovation and Excellence, Kumamoto University
Institute of Pulsed Power Science, Kumamoto University
Ozone is a natural oxidizing agent with strong power which is almost equal to fluorine; it thus provides
many effects such as sterilization, deodorization, and decolorization. As such, ozone applications have extended
over-fields such as the treatment of air, water and soil [1-2].
Because the ozone generation process utilizing nano-seconds pulsed generator still has some unclear
technical knowledge, its investigations need to get higher energy efficiency of ozone generation and higher
density of ozone. The ozone distribution on temporal and spatial in the discharge reactor during the process is one of
the important knowledge.
In this study, the measurement of ozone have been done by the laser absorption method, which allows
us to get the ozone distribution with higher resolution. In the experiment, the nano-seconds pulse generator
having 5 ns duration and the discharge electrode having 1 m lemgth have been utilized. In the manuscript, the
increased, saturated and decreased process of ozone with increasing the input energy density would be cleared
and discussed. From the discussion, the way to ozone generation with the higher yield and concentration would
hopefully be found.
References:
R. Ono and T. Oda, Dynamics and density estimation of hydroxyl radicals in a pulsed corona discharge, J. Phys.
D, vol.35, pp. 2133-2138, 2002.
R. Ono and T. Oda, Dynamics of ozone and OH radicals generated by pulsed corona discharge in humid-air flow
reactor measured by laser spectroscopy, J. Appl. Phys., vol. 93, pp. 5876-5882, 2003.
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-44
Investigation on Post-Discharge Phenomena of Laser-triggered Discharge
Plasma for EUVL
Seiya Kitajima*1, Soowon Lim1, Takashi Kamohara1, Sunao Katsuki2 and Hidenori Akiyama2
Graduate School of Science and Technology, Kumamoto university, Kumamoto, 860-8555 Japan
Institute of Pulsed Power Science, Kumamoto university, Kumamoto, 860-8555 Japan
High-frequency operation of extreme ultraviolet (EUV) source is essential to satisfy the high volume
manufacturing requirements [1-4]. This paper reports the dynamic post-discharge phenomena of laser-triggered
discharge-produced plasmas (LTDPP) for EUV lithography (EUVL) sources. A pulsed laser was focused on
the high-voltage tin cathode surface to form tin vapor jet across a 5 mm long anode-cathode gap, which leads to
the electrical breakdown. The post-discharge phenomena were observed using both of the Schlieren method and
high-speed camera. Schlieren images show the dynamic evolution of the discharge plasma and the development
of tin droplets. Visible emission from the plasma lasted for more than 1 μs after the current stopped. The droplets
emerged from the cathode approximately 100 μs after discharge and spread throughout the electrodes gap.
Various sizes of droplets stagnate in the gap for milliseconds. Tin vapor density decreased with the time,
and the decrease was delayed with increasing the discharge energy. The electrical recovery of the gap seems to be
in accordance with the history of the vapor density. Tin droplets are unlikely to influence the electrical
recovery significantly. The subsequent laser pulse and voltage application show an interaction between the
droplets and the subsequent discharge. The subsequent laser pulse evaporates not only the cathode surface but also
the droplets, which influence the tin vapor distribution in the gap. This uncertain vapor distribution affects the
formation process of micro-plasmas that emit EUV.
References:
Jos Benschop, “EUV: Status and Challenges Ahead”, presented at the 2010 International Workshop on
EUV Lithography, Maui, Hawaii, USA, Jun. 21-25, 2010.
V. Bakshi, “Status and Future of High Power EUV Source Technology”, presented at the 2010 International
Workshop on EUV Lithography, Maui, Hawaii, USA, Jun. 21-25, 2010.
Vadim Banine, “EUV Lithography and EUV Sources”, presented at the 2011 International Workshop on
EUV and Soft X-ray Sources, Dublin, Ireland, Nov. 7-10, 2011.
V. Bakshi, EUV Source for Lithography (SPIE, Bellingham, WA, 2006).
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-45
Applications of DC Superimposed Nano-Seconds Pulsed Discharge
M. Yanagida*1, Y.Fukuchi1, D. Wang2, T. Namihira3 and H. Akiyama3
Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Chuo-ku, Kumamoto 8608555, JAPAN
Priority Organization for Innovation and Excellence, Kumamoto University
Institute of pulsed power science, Kumamoto University
In recent years, industrial applications of non-thermal plasmas such as dielectric barrier discharge (DBD),
do corona discharge, surface discharge, nano-seconds pulsed streamer discharge have been active. In particular,
nano-seconds pulsed discharge having quit shorter duration is very effective in reducing energy loss due to heating
by stopping voltage application before the discharge phase shifts to thermal phase. For the industrial applications,
the impedance matching between the generator and the discharge reactor is one of the most important factors for
the energy efficiency of the processing [1].
In this study, in making the nano-seconds pulsed discharge in the coaxial cylindrical electrode, the dc bias
voltage would be applied. The dc bias voltage could control the discharge condition easily and give the best condition
for impedance matching between generator and electrode. In the paper, the dependences of pulse applied voltage,
pulse applied frequency and superimposed dc voltage on discharge phenomena would be investigated. Further, the
ozone generation experiment with dc bias nano-seconds pulsed discharge would carry out.
References:
T. Namihira, D. Wang, T. Matsumoto, S. Okada, H. Akiyama, “Introduction of nano-seconds pulsed discharge
plasma and its applications”, IEEJ Transactions on Fundamentals and Materials, Vol.129, No.1, pp7-14, 2009.
S. Shibuta, D. Wang, T. Namihira, H. Akiyama, “Influence of Multiple Wire Electrode by Nano- seconds Pulsed
Discharges”, Proceedings of the Institute of Electrostatics Japan, Vol.37, No.1, pp2-7, 2013.
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-46
Behavior of Micro Droplets Ejected by Electrospray Dependent on Voltage
Waveform
Hiroshi Tasaka*1, Daichi Obata1, Sunao Katsuki2 and Hidenori Akiyama2
Graduate School of Science and Technology, Kumamoto University, Japan
Institute of Pulsed Power Science, Kumamoto University, Japan
Liquid atomization by applying a high voltage to a liquid meniscus at a thin nozzle is known as electrospray or
electrohydrodynamic-spray, which is widely used in industries such as paint spraying, pesticide spraying, ink-jet
etc. Although the steady state behaviors in the conventional DC- and AC-driven electrosprays have been discussed
and mostly clarified theoretically and experimentally, there are only a few studies on a transient mode driven by
a pulsed voltage. This paper describes the hydrodynamic behavior of the micro droplets ejected by electrospray
and its dependence on the rise time of a pulsed voltage. Pulsed voltages were produced by chopping a DC
high voltage using a MOS-FET module, and its rise-time was adjusted by an external resistance-capacitance circuit.
The range of the rise time, from 50 ns to 2 μs, is much smaller than the hydrodynamic time constant of ethylene
glycol as the liquid material. A titanium-coated glass tube with an outer diameter of 40 μm was used as the nozzle.
The microscopic images of the liquid meniscus on the nozzle tip were taken by using the laser shadowgraph
method with a magnification optics, and the droplets attached to the target glass plate were evaluated. We present
the details of the experiment.
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-47
Carbon Material Formation by Decomposition of Carbon Dioxide Using
Pulsed Arc Discharge
Kiminibu Imasaka*, Takahiro Nakamura, Kouhei Nakao, Kazuki Ohtsuka, Shiyun Kawazu and Kosuke
Furukawa
Dept. of Electrical Engineering and Information Technology, Kyushu Sangyo University, Fukuoka 8138503, Japan
Rapid increase of carbon dioxide (CO2) in recent years will lead to increase of atmospheric temperature in
the earth and affect to global geographical changes. Therefore, the decomposition and deduction of carbon dioxide
is an important subject for environmental problems. Carbon material formation from the decomposition of carbon
dioxide by plasma methods was one of approaches for solution of the problems [1].
In this study carbon dioxide was decomposed and carbon material was formed by pulsed arc discharge. Pulsed
arc discharge between electrodes was generated by a pulsed power generator which was fabricated in our
laboratory. Carbon dioxide was flowed between electrodes in atmospheric air. Several types of electrode
materials and shapes were utilized. After repetitive pulsed arc discharge with and without carbon dioxide gas
flow, surface of the electrodes was observed and analyzed using a scanning electron microscope instrument with
x-ray analyzer.
Figure 1 shows SEM images of the electrode surface after the repetitive pulsed arc discharge. It was found
that large number of fine particle was formed on the surface after the discharge in carbon dioxide. Material of
these particles was recognized as carbon from the measurement with x-ray analyzer. Carbon material produced
on the electrode surface by the discharge in carbon dioxide was increased to about 26 wt% from 3 wt% in
case of that without carbon dioxide. The obtained result shows a promising possibility of carbon material
formation by the decomposition of carbon dioxide using pulsed arc discharge.
Without
With
Figure 1. SEM images of electrode surface after repetitive pulsed arc discharge with and without carbon
dioxide.
References:
M P Srivastava and A. Kobayashi, Trans. of JWRI, Vol. 39, pp. 11-25, 2010.
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-48
Characteristics of Polymer Electrolyte Fuel Cell Using Surface Modified
Carbon Nanotubes by Ozone Produced by Pulsed Arc Discharge
Kiminobu Imasaka*, Michihiko Terayama, Soushi Matsuyuki, Toshihiro Uchikawa, Akimitsu Hatanaka
and Tomohiko Yamashita
Dept. of Electrical Engineering and Information Technology, Kyushu Sangyo University, Fukuoka 813-8503, Japan
Polymer electrolyte fuel cell (PEFC) promises to be a clean energy generator. One of the most important
components of PEFC is a membrane electrode assembly (MEA). A PEFC fabricated by the MEA using a catalyst
Pt-deposited carbon nanotube electrodes showed higher performance than that of a conventional Pt-deposited
carbon black [1].
In this study multi-walled carbon nanotubes (MWCNTs) were used as the electrode material of MEA. The
surface-modified MWCNTs by ozone which was produced by pulsed arc discharge were also used for it and
output characteristics of PEFC were investigated. Figure 1 shows a configuration of PEFC and MEA. The MEA
was fabricated by a hot press method of a solid polyelectrolyte membrane and electrodes which were composed
of ozone-treated MWCNTs supported by Pt on their surfaces. Figure 2 shows a SEM image of MEA. It was
found that MWCNTs were widely dispersed on a carbon paper which was used for a base electrode material and
the Pt catalyst was attached on the surface of MWCNTs. The ozone treatment of MWCNTs was performed by
pulsed arc discharge in atmospheric air changing treatment time. Surface modification of MWCNTs by ozone
was analyzed with FTIR and XPS equipment. FTIR and XPS measurements showed that carboxylate ion was
introduced into the surface of ozone-treated MWCNTs. Dispersibility of MWCNTs in polyelectrolyte solution
which was important process in MEA fabrication would be improved by introduction of carboxylate ion onto their
surfaces. The ozone-treated MWCNTs were used for the fuel electrode (Anode) and/or oxygen electrode (Cathode)
and then output voltage and current characteristic (V-I characteristic) of the PEFC was investigated. The V-I
characteristic was extremely depended on combination of the electrodes with and without ozone-treated MWCNTs.
M
MWC
P
Figure 1. Configuration of PEFC and MEA. Figure 2. SEM image of MWCNT/Pt electrode surface.
References:
T Matsumoto, T Komatsu, H Nakano, 1, K Arai, Y Nagashima, E Yoo, T Yamazaki, M Kijima, H Shimizu, Y
Takasawa and J Nakamura, Catalysis, Vol. 90, Issues 3, pp. 277-281, 2004
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-49
Cooling Effect on Ozone Generation Using Nanosecond Pulsed Discharge
Naoki Abe*1, Yuta Yamato2, Douyan Wang3, Takao Namihira4 and Hidenori Akiyama4
Graduate School of Science and Technology, Kumamoto University, Kumamoto 860-8555, Japan
Department of Computer Science and Electrical Engineering, Kumamoto University
Priority Organization for Innovation and Excellence, Kumamoto University
Institute of Pulsed Power Science, Kumamoto University
Our research group has recently demonstrated the high energy efficiency of non-thermal plasma using
nanosecond (ns) pulsed discharge in the generation of ozone. However, maximum ozone concentration saturates at
3 [1]
approximately 40 g/m . For industrial application, a ns pulsed discharge based ozonizer is required a higher
ozone concentration of around 120 g/m3. In the field of ozone generation by dielectric barrier discharge, many
researchers have reported that the gas temperature in ozonizers strongly affects on characterization of the ozone
generation and Dr. Suehiro demonstrated that ozone generation with cryogenic cooling by liquid nitrogen gives
[2]
higher ozone concentration due to suppression of ozone decomposing reaction.
In this work, the influence of cryogenic cooling on ozone generation (concentration and yield) using ns pulsed
discharge was experimentally investigated. The discharge reactor consisted of coaxial cylindrical configuration and
outer cylinder was made cool by liquid nitrogen. The electrode gap space was cooled into approximately 160 K. It
was found that ozone concentration and yield increased with decreasing temperature in reactor the cooling effect
particularly remarkable in the high input energy density region. The ns pulsed generator used in the work can output
pulsed duration of 5ns with a 2ns rise and fall time.
References:
T. Matsumoto, D. Wang, T. Matsumoto, S. Okada, H. Akiyama, “Gas temperature measurements of nanoseconds pulsed discharge based ozonizer”, 2011 IEEE Pulsed Power Conference, pp. 1088 -1092, 2011.
J. Suehiro, M. Takahashi, Y. Nishi, W. Ding, K. Imasaka, M. Hara, “Improvement of the Ozone Generation
Efficiency by Efficiency by Silent Discharge at Cryogenic Temperature”, IEEJ Trans. FM, Vol.124, No.9, 2004.
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-50
Decomposition of Toluene by Using Nano-seconds Pulsed Discharge Plasma
Assisted with Catalysts
Akihiko Ogasawara*1, Jun Kai Han1, Jinlong Wang2,
Douyan Wang3, Takao Namihira4, Hidenori Akiyama4 and Pengyi Zhang2
Graduate School of Science and Technology, Kumamoto University, Kumamoto 860-8555, Japan
School of Environment, Tsinghua University, Beijing 100084, China
Priority Organization for Innovation and Excellence, Kumamoto University, Kumamoto 860-8555, Japan
Institute of Pulsed Power Science, Kumamoto University, Kumamoto 860-8555, Japan
Volatile organic compounds (VOCs) are common air pollutants in various atmospheric environments [1]. In
addition, VOCs have possibilities of generation of suspended particulate matter and photochemical oxidant [2].
Ozone (O3) is closely associated with the formation of airborne fine particles and toxic chemicals. Air pollution
has both acute and chronic effects on human health, affecting a number of different systems and organs.
Efficient removal methods of air pollutants are strongly required.
Environmental catalysis research is undergoing a transition from pollution abatement to pollution prevention.
The catalytic (MnOx) [3] and photocatalytic oxidation (Pd-TiO2/Ti) [1] can eliminate various kinds of VOCs as
well as O3 with the potential to improve indoor air quality. However, neither catalysis nor photocatalysis work in high
VOCs concentration.
Many researchers have been reported regarding the synergetic effect of plasma catalysis, the integration of
non-thermal plasma and catalysis, on VOCs removal. This novel technique combines the advantages of fast
ignition/response from non-thermal plasma and high selectivity from catalysis. It has been successfully demonstrated
that plasma catalysis could serve as an effective solution to the major bottlenecks encountered by non-thermal
plasma, i.e., the reduction of energy consumption and unwanted/hazardous byproducts [4].
In our previous study, toluene decomposition ratio increased with increasing the peak of applied voltage
to the discharge reactor, and reached 100 % in case of air ambient gas with the 50 kV of applied voltage with
high energy efficiency compared with DC corona discharge method [2]. However, many issues remain prior to
industrial implementation, including energy efficiency reduction due to remove residual formic acid, carbon
monoxide, and O3 as byproducts, as well as working limitation in low VOCs concentration.
Therefore, in this work, synergetic effect by coupling catalysts with energy efficient nano-seconds pulsed
discharge for high concentration of toluene decomposition is experimentally clarified and its detailed results will
be presented at the conference.
References:
P. Fu, P. Zhang, J. Li, “Photocatalytic degradation of low concentration formaldehyde and simultaneous
elimination of ozone by-product using palladium modified TiO2 films under UV254+185nm irradiation”,
Applied catalysis B: environmental 105 (2011) 220-228
Y. Araki, D. Wang, T. Namihira, H. Akiyama, “Toluene decomposition using nano-seconds pulsed discharge”,
The proceedings of IEEE 2011
J. Q. Torres, S. Royer, J. P. Bellat, J. M. Giraudon, and J. F. Lamonier, “Formaldehyde: Catalytic Oxidation as a
Promising Soft Way of Elimination”, ChemSusChem, 6 (2013) 578-592
H. L. Chen, H. M. Lee, S. H. Chen, M. B. Chang, S. Jenyu, and S. N. Li, “Removal of Volatile Organic Compounds
by Single-Stage and Two-Stage Plasma Catalysis Systems: A Review of the Performance Enhancement
Mechanisms, Current Status, and Suitable Applications”, Environ. Sci. Technol. 2009, 43, 2216–2227
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-51
Diesel Exhaust Treatment by Nano-seconds Pulsed Discharge in Coaxial
Electrode
Yuichi Fukuchi*1, Munemasa Yanagida1 , Douyan Wang2, Takao Namihira3 and Hidenori Akiyama3
Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Chuo-ku, Kumamoto 8608555, Japan
Priority Organization for Innovation and Excellence, Kumamoto University
Institute of Pulsed Power Science, Kumamoto University
Diesel exhaust gasses may cause some environmental problems such as air pollution, acid rain and so on.
Presently, the improvement of combustion is one of the reduction ways of diesel pollutants. However, it is
not sufficient to protect the environment. Therefore, the diesel engine needs the after treatment system and
presently install the urea-SCR (selective catalyst reaction) and DPF (diesel particle filter). On the other hands, it
is well known that the non-thermal plasma generated by pulsed discharge could remove NO and collect particle
matters from diesel exhaust gas [1]. Recently, the nano-seconds pulsed discharge was developed and it has higher
energy efficiency for some processing [2].
In this work, the nano-seconds pulsed discharge has been employed to treat the exhaust gas from the diesel
generator. In the paper, the treatment characteristics of the diesel exhaust by the nano-seconds pulsed discharge
would be described. Especially, the energy efficiency for NO removal and particle matters collection would be
discussed.
References:
D.Wang, K.Fujiya, T.Namihira, S.Katsuki and H.Akiyama “Diesel exhaust control using a magnetic pulse
compressor”, Pulsed Power Conference, 2003. Digest of Technical Papers. PPC-2003. 14th IEEE
International 1270 - 1273 Vol.2
D. Wang, T. Namihira and H. Akiyama, “Pulsed Discharge Plasma for Pollution Control”, Air Pollution, Vanda
Villanyi (Ed.), ISBN: 978-953-307-143-5, InTech, 2010
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-52
Generation of Hydrogen Peroxide in Gas Bubbles Using Pulsed Plasma for
Advanced Oxidation Processes
Ryo SAEKI* and Koichi YASUOKA
Department of Electrical and Electronic Engineering, Tokyo Institute of Technology, Tokyo 152-8552, Japan
Treatment of wastewater with high concentrations of total organic carbon (TOC) has recently become a
serious environmental problem. Because offshore oil plants generate large amounts of high- conductivity TOC
wastewater, rapid and inexpensive treatments are required for treating such wastewater. Advanced oxidation
process (AOP) is one of the most effective methods for decomposing persistent organic pollutants in water using
OH radicals. The O3/H2O2 method, one of the AOP methods, is widely used to generate OH radicals.
However, this method is not suitable for oil plants because it requires continuous H2O2 supply. Direct
generations of OH radicals [1] and H2O2 [2] by plasma have also been studied. However, it is difficult to apply
these methods to high-conductivity water generated at oil plants.
To overcome these problems, in our research we generated H2O2 in oxygen gas bubbles by using pulsed
plasma [3] for the O3/H2O2 method. This system can be adapted to high-conductivity wastewater and can
continuously generate H2O2 from the materials available on offshore oil plants, such as water, oxygen (or air),
and electricity. In this study, plasma conditions suitable for H2O2 formation were investigated by changing the
parameters of the pulsed plasma (applied voltage, pulse width, and pulse frequency) and the amount of vapor in
oxygen.
Fig. 1 shows the H2O2 energy yield as a function of pulse width and voltage. The figure indicates that the
low-voltage-driven and long pulse-width plasma afforded the highest energy yield of H2O2. Fig. 2 shows the
H2O2 energy yield as a function of frequency and the amount of water vapor. This figure shows that the energy
yield of H2O2 improved on introducing steam into the supply gas.
This work was supported by JSPS KAKENHI grant no. 26249032.
Fig. 1. Generation rate of hydrogen peroxide vs.
Fig. 2.
Energy yield of hydrogen peroxide vs.
frequency with various amounts of water vapor.
voltage and pulse width at constant power.
References:
E.N. Tamungang, S. Laminsi, Chemical Engineering Journal, Vol. 173, No. 2, 2011.
B.R. Locke, K.Y. Shih, Plasma Sources Sci. Technol., Vol. 20, No. 3, 2011.
K. Yasuoka, K. Sasaki, and R. Hayashi, Plasma Source Sci. Technol., Vol. 20, No. 3, 2011.
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-53
Elucidation of the Molecular Conversion Behavior of Amino Acids via Pulse
Discharge at Argon/Water Interface
Yuka Sakai1, Yusuke Hirano1, Armando T. Quitain1, Mitsuru Sasaki2* and Kunio Kawamura3*
Graduate School of Science and Technology Kumamoto University, Kumamoto 860-8555, Japan.
Institute of Pulsed Power Science, Kumamoto University, Kumamoto 860-8555, Japan.
Hiroshima Shudo University, Hiroshima 731-3195, Japan.
1.Introduction
Peptides are molecules having the amino acid polymer structure, and it is used as health supplements,
pharmaceutical products and sweeteners. In general, they are synthesized by using a condensing agent and enzymes,
but these synthesis methods have problems to need a long reaction time or to generate a large amount of waste. The
aim of our study is to develop the new peptide synthesis method using a pulsed discharge as a means of resolving
these problems.
Discharge is a phenomenon that electricity flows through insulator when the large potential difference occurs
in the insulator. The electrons are not generated in the normal state and have high- energy. Thus they role the starting
point of the reaction and chemical reactions can rapidly proceed.
In this study, we was investigated of the ability to polymerize of amino acid by discharge plasma at the gasliquid interface.
2.Experiment
We use Glycylglycine ((Gly)2) and Alanylalanine ((Ala)2) as raw materials. (Gly)2 and (Ala)2 were dissolved
in distilled water at a fixed concentration of 0.1M and pH was adjusted by adding NaOH or H2SO4, respectively. We
used this aqueous solution as a starting material in the study. The discharge experiment was performed in a SUS316
reactor. The starting material (5 mL) was added to the reactor. A copper electrode covered by polytetrafluoroethylene set up as a high-voltage electrode. After the reactor sealed, it was filled with Argon. Then the discharge was
started under the atmospheric pressure. The discharge state was arcing in this experiment. The experiment was
done under several pH, discharge time of discharge frequency. After the discharge, reaction solutions were
taken out and cooled to room temperature. The reaction solutions were analyzed by HPLC and LC/MS.
3.Result and Discussion
In the case of discharge experiment for (Ala)2, the
component of C8H14N2O3 which have 26 more molecular
weight than (Ala)2 was formed in quantities. Also the
generation of C5H9NO2 and C7H14N2O which were
formed in the decomposition of C8H14N2O3 was
confirmed. From these molecular formula, we considered
alanyl- proline has been produced by methyl group
desorbed from (Ala)2 added to another (Ala)2. On the other
hand, In case a pH of 8.7, the generation of tetramer
alanine was seemed. Trace amount of trimer were also
detected at the same time. From this result, we considered
amino acid polymerization is possible in near-neutral pH.
Fig. 1 Possible reaction pathway for the pulsed
discharge of (Ala)2 in water.
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-54
Odor Treatment System Using Solid-state Pulsed Power Modulator
Sung-Roc Jang *1, Hong-Je Ryoo1, Suk-Ho Ahn2, Sung-Hun Park1 and Geun-Hie Rim1
1) Korea Electrotechnology Research Institute (KERI), Changwon, Korea
2) University of Science & Technology (UST), Deajeon, Korea
This paper describes the application study of odor treatment system using solid-state pulsed power
modulator. The advantages of IGBT switch based solid-state pulsed power modulator such including highrepetition rate, high-efficiency, fast rising time without MPC provides effective odor treatment [1, 2]. In addition,
the easiness of controlling the output pulse voltage, width, as well as repetition rate allows investigating and
comparing the effective treatment conditions depending on not only the output pulse but also the reactor
structure. The gases such including ammonia, amine and toluene were tested with different types of plasma
reactor and the maximum treatment results of each gas were measured as 67%, 43% and 100%, respectively.
Detailed configurations of the gas treatment system and the results are discussed in the following paper.
Fig. 1. Experimental waveforms, pictures and results of gas treatment systems.
References:
[1] Seung-Bok Ok; Hong-Je Ryoo; Sung-Roc Jang; Suk-Ho Ahn; Goussev, G.; , "Design of a High- Efficiency 40-kV,
150-A, 3-kHz Solid-State Pulsed Power Modulator," Plasma Science, IEEE Transactions on , vol.40, no.10,
pp.2569-2577, Oct. 2012
[2] Sung-Roc Jang; Hong-Je Ryoo; Goussev, G.; Geun Hie Rim; , "Comparative Study of MOSFET and IGBT for
High Repetitive Pulsed Power Modulators," Plasma Science, IEEE Transactions on , vol.40, no.10, pp.25612568, Oct.
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-55
Ozone Generation by Nano-Seconds Pulsed Discharge at High Atmospheric
Pressure Gas
H.Sato*1, K.Fuji1 , D.Wang2 , T.Namihira3 and H.akiyama3
Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Chuo-ku, Kumamoto 8608555, Japan
Department of Computer Science and Electrical Engineering, Kumamoto University
Priority Organization for Innovation and Excellence, Kumamoto University
Institute of pulsed power science, Kumamoto University
In recent years, discharge plasma in atmospheric pressure gases has been studied and is a promising
technology for the removal of hazardous environmental pollutants and the generation of ozone.In our laboratory,
an ozone generation system using nano-seconds (ns) pulsed discharge plasma, which has 5 ns pulsed duration,
has been developed and the ozone generation characteristics have been studied for several years [1]. However,
for all research is only under atmospheric pressure gas. A study of the ozone generation under the high pressure
condition is found to satisfy needs of the ozone generation to diversify[2].
In this study, ozone was generated by pulsed discharge in order to improve the characteristics of ozone
generation at high atmospheric pressure gas. The discharge reactor was consisted of pin-to-plate and gas pressure
is 0.1-1.0 MPa. It was found that the generated ozone density decreased so that gase pressure was higher and
higher. This study show possibility of the application to the new field of the ozone generation using nano-seconds
(ns) pulsed discharge plasma.
References:
T. Matsumoto, D. Wang, T. Matsumoto, S. Okada, H. Akiyama, “Gas temperature measurements of nanoseconds pulsed discharge based ozonizer”, 2011 IEEE Pulsed Power Comference, pp.1088 – 1092, 2011.
Taisuke Shiraishi ："A Study on the Effect and Mechanism of Plasma Assisted Gasoline HCCI Combustion by
Low Temperature Plasma", COMODIA 2012，July 23-26, 2012
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-56
THCD Electron Beam in a Metallic Capillary Discharge
L. S. Chan*, D. Tan, S.L. Yap and C. S. Wong
Plasma Technology Research Centre, Physics Department, University of Malaya, 50603, Kuala Lumpur, Malaysia.
A different mode of operation of metallic capillary discharge is developed [1]. In this mode of operation,
the transient hollow cathode discharge (THCD) electron beam plays an important role in instigating the capillary
discharge and subsequently affect the emission of the metallic capillary plasma. The plasma formed in the capillary
emits in the EUV and visible region. It is observed that operating pressure affect the efficiency of the function of
the THCD electron beam in our metallic capillary discharge.
References:
[1]
L.S. Chan, D. Tan, S. Saboohi, S. L. Yap, and C. S. Wong, “Operation of an electron beam initiated
metallic plasma capillary discharge”, Vacuum, Vol. 103, pp. 38-42, 2014.
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-57
Comparative Study on Collisionless Shock Generated by Taper-cone-shaped
Plasma Focus Device
Hiroki Kinase*, Taichi Takezaki, Kazumasa Takahashi, Toru Sasaki, Takashi Kikuchi and Nob. Harada
Nagaoka University of Technology, Niigata 940-2188, Japan
Collisionless shocks induce several phenomena such as energy dissipation through an electromagnetic field
and generation of high-energy particles in the shock front. To understand such mechanisms, laboratory scale
experiments are required with well-defined parameters such as plasma beta and shock velocity. To generate the
collisionless shock in the laboratory scale experiments, Drake [1] has considered the scaling parameters for the
astrophysical phenomena. In this study, we investigated the behaviors of the hypersonic plasma flow in an
applied magnetic field with a laboratory scale experiment and numerical simulations.
The hypersonic plasma flow is generated with a taper-cone plasma focus system [2]. The plasma focus
system consists of a capacitor bank, a cone electrode, a tapered electrode, and an acrylic guiding tube. The acrylic
guiding tube with a constant cross-section is located on the top of tapered electrode. The optical emission from
the plasma flow, which corresponds to the shock velocity, is directly observed with a streak camera. Permanent
magnets for applying magnetic field are set on the acrylic guiding tube. The distributions of applied magnetic
field are Gaussian-shaped and uniform conditions. The peak magnetic flux density in the Gaussian-shaped
condition is 200 mT at 8 mm from the inlet of the acrylic guiding tube. The magnetic flux density in the uniform
condition is 260 mT.
Figure 1 shows the streak image of the plasma flow for the different applied magnetic fields. As shown
in Fig. 1(a), the shock velocity decelerated at the peak of the magnetic flux density. On the other hand,
significant deceleration of the shock velocity in the case of uniform applied magnetic field was not observed as
shown in Fig. 1(b). These results indicate that the deceleration of shock velocity depends on the spatial distribution
of the magnetic field. We also performed a 1.5-dimensional hybrid particle-in-cell (PIC) simulation and full PIC
simulation. From the comparison with the experimental results and the numerical results, the plasma behaviors
are similar in the applied magnetic field.
0
t [µs]
8.6
x [mm]
10
11.8 km/s
20
9.6km/s
11.1
13.6
(a) Magnetic field of Gaussian distribution.
(b) Magnetic field of uniform distribution.
Fig. 1. Streak images of hypersonic plasma flow in the acrylic tube
References:
R. P. Drake, "The design of laboratory experiments to produce collisionless shocks of cosmic relevance",
Phys. Plasmas 7, 4690 (2000).
T. Sasaki, et. al., “Laboratory Scale Experiments for Collsionless Shock Generated by Taper-cone-shaped
plasma Focus Device”, J. Phys. Soc. Proc., 1, 015096 (2014).
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-58
Investigation of Effects of Pulse Frequency on Physical Properties of Electrothermal Pulsed Plasma Thruster
J. Eguchi*1, T. Sakamoto1, Y. Ebata1, S. Katsuki2 and H. Akiyama2
Graduate School of Science and Technology, Kumamoto University, Kumamoto 860-8555, Japan
Institute of Pulsed Power Science, Kumamoto University, Kumamoto 860-8555, Japan
The pulsed plasma thruster (PPT), an electromagnetic thruster whose thrust force derives from the Lorentz
force, is a most reliable electric propulsion system due to advantages inherent to the PPT thruster system:
simplicity, light structure, and small volume [1]. As such, PPT would be an attractive propulsion system for small
satellites. Moreover, studies of electro-thermal PPTs, whose thrust force derives from aerodynamic acceleration,
have recently attracted increased interest. As electro-thermal PPTs can achieve a larger thrust than electromagnetic
PPTs, they are suitable for missions requiring large changes in velocity (∆V) such as formation flying and orbit
maneuver [2]. Propulsion efficiency of electro-thermal PPTs remains low, however, and despite the studies
conducted, sufficient performance has not been achieved. This study investigates effects of power supply pulse
frequency on plasma resistance as well as physical properties of the plasma in order to improve propulsion
system performance by optimizing pulse characteristics.
A unique electro-thermal PPT was developed to observe effects of pulse frequency. PPT operations were
performed by pulsed discharge using energy charged in the capacitor bank through ignition of the igniter. Input
energy was fixed at 20 J, with circuit inductance constant. Pulse frequency was modified by varying the
capacitance value. Plasma resistance was derived from the difference between applied voltages, while charging
voltage drop was determined by the short circuit on the voltage waveform. Regarding physical properties of the
plasma, the light emission of the plasma was observed by spectroscope to allow measurement of plasma temperature,
electron temperature, and electron density by black body radiation, the relative intensity method, and Stark
broadening. Based on resistance values, physical properties of the plasma were measured, effects of the frequency
of the power supply on electro-thermal PPT were analyzed, and those leading to performance enhancement are
described.
References:
Michael Keidar, Iain D. Boyd, and Isak I. Beilis, “Electrical Discharge in the Teflon Cavity of a Coaxial Pulsed
Plasma Thruster”, IEEE Transactions on Plasma Science, Vol. 28, No. 2, pp. 376- 385, April 2000.
Junichiro Aoyagi, Masayuki Mukai, Yukiya Kamishima, Tsubasa Sasaki, Kouhei Shintani, Haruki Takegahara,
Takashi Wakizono, and Mitsuteru Sugiki, “Total impulse improvement of coaxial pulsed plasma thruster for
small satellite”, Vacuum, Vol. 83, Issue 1, pp. 72-76, 2009.
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-59
Study of Effect of Pulse Frequency on the Propulsion Performance in the
Electrothermal Pulsed Plasma Thruster
Y. Ebata*1, T. Sakamoto1, J. Eguchi1, S. Katsuki2 and H. Akiyama2
1) Graduate School of Science and Technology, Kumamoto University, Kumamoto 860-8555, Japan
2) Institute of Pulsed Power Science, Kumamoto University, Kumamoto 860-8555, Japan
Electrothermal pulsed plasma thrusters (Et-PPTs) have attracted much attention as electric propulsion in
the development field of small satellites due to their small size, high reliability, and low cost [1]. However,
propulsion efficiency remains low despite the great amount of research conducted to date, and Et-PPTs are far
from achieving performance sufficient for practical use.
One reason for the low propulsion efficiency of Et-PPTs is low plasma resistance. This plasma
resistance is affected both by the structure of the thruster as well as by temporal, unsteady phenomena. In this
study, we evaluate the supplied pulse frequency, plasma resistance, overall energy loss of the thruster, and
propulsion performance so as to provide guidelines to improve propulsion performance.
Experiments were conducted using an Et-PPT with either a 3.5mm or 4.0mm cavity diameter and 20mm
cavity length. By varying power supply parameters such as capacitance or charging voltage in a state of fixed
stored energy of 20J, energy was supplied to the propulsion unit with a current pulse width of from a few
hundred nano-seconds to a few micro-seconds. We subsequently investigated the effects of pulse frequency on
plasma resistance and loss of thrust by calculating from current and voltage waveforms Based on these, we
present guidelines for improvement of thruster performance.
References:
[1] T. Edamitsu and H. Tahara, “Performance Characteristics and Repetitive Operation of a High-Impulse
Electrothermal Pulsed Plasma Thruster”, JSASS collection of papers, Vol. 54, No. 625, pp. 55-62, 2006.
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-60
Electron Emission Characteristics of Electrode toward Warm Dense DiamondLike Carbon Generation by Using Flyer Impact with Intense Pulse Power
Generator
Takahiro Kudo*1, Naoto Takakura1, Tomoaki Ito1, Fumihiro Tamura1, Ryota Hayashi1, Kazumasa
Takahashi1, Toru Sasaki1, Takashi Kikuchi1, Nob. Harada1, Weihua Jiang1, Kenji Kashine2, Akira Tokuchi1,3
and Shinsuke Fujioka4
Nagaoka University of Technology, Japan
Kagoshima National College of Technology, Japan
Pulsed Power Japan Laboratory Ltd., Japan
Osaka University, Japan
A guiding-cone is used to increase the energy conversion efficiency from fast electrons to core plasma
for fast ignition of inertial confinement fusion. Diamond-like carbon (DLC) is one of candidates as the guidingcone material due to the improvement of conversion efficiency [1][2]. Physical properties of warm dense
DLC affect the conversion efficiency in the irradiation of ignition laser. To evaluate the properties, we consider a
measurement method for the warm dense DLC.
We proposed a method to generate the warm dense DLC by using flyer impact accelerated with electron
beam irradiation. The flyer impact method has advantages such as well-defined plasma parameters and
determination of state of matter using Rankine-Hugoniot relation. The flyer is accelerated by counteraction of
ablation plasma generated by the irradiation of electron beam. The electron beam is provided with the intense
pulsed power generator “ETIGO-II”[3].
In this study, to generate warm dense DLC, we have measured the electron beam current with the electron
beam diode structure in the ETIGO-II. To focus the generated electron beam, the curved shape electrodes
having 135 mm of curvature radius are set on the terminal of ETIGO-II [4]. A gap distance between anode and
cathode in the electron beam diode is 10 mm. To confirm the geometrical effect, the anode was set as blade or
mesh structures. The focused electron beam irradiated to an acrylic plate. The acrylic plate was placed to
observe Lichtenberg patterns. Figure 1 shows photographs of the acrylic plates irradiated by electron beam
using the blade and mesh anodes. The result indicated that the electron beam for the mesh anode concentrates
around the center of the acrylic plate in comparison to that for blade anode.
It was revealed that focus condition of the electron beam depends on the diode anode toward the warm
dense DLC generation by using the flyer impact irradiating intense electron beam.
(a)
(b)
Fig.1 Photograph of the anode electrode (left) and acrylic plate (right) irradiated by electron beam with (a)
the blade anode, (b) the mesh anode.
References:
S. Fujioka, et al., Plasma Physics Controlled Fusion 54, 124042 (2012)
P. McKenna, et al., Physical Review Letters 106, 185004 (2011)
W. Jiang, et al., Jpn. J. Appl. Phys. 32, L752 (1993)
F. Tamura et al., The 41st IEEE International Conference on Plasma Science and the 20th International
Conference on High-Power Particle Beams, 2P-85 (2014)
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-61
Observation of High-Energy Ions in the SHOTGUN III Divergent Gas-Puff ZPinch Experiment
Keiichi Takasugi*1, Masayuki Iwata1 and Mineyuki Nishio2
1) Institute of Quantum Science, Nihon University, Tokyo 101-8308, Japan
2) Anan National College of Technology, Tokushima 774-0017, Japan
The divergent gas-puff z pinch is an efficient system aimed at the 3-dimentional convergence of plasma.
Hard x-ray radiation about 200 keV has been observed in the divergent gas-puff z-pinch experiment, and the
generation of high-energy electron was confirmed [1]. It has also been confirmed from the ion energy analysis that
the ions about 1 MeV has occurred at the same time. As the high- energy ions were also observed in the reversed
current experiment, the generation of high-energy ions was believed to be independent of the current direction [2].
In order to understand the mechanism of ion acceleration, the ion pinhole measurement was planned to identify the
source and the process of ion emission.
The experiment was carried out on the SHOTGUN-III device at Nihon University. The device is operated
with 12 µF capacitor bank, which can be charged positively or negatively. Typical discharge current is about 150 kA
at the charging voltage of 25 kV. 10 degrees divergent annular gas nozzle was installed on a center electrode of the
device. Argon gas was used for the experiment, and the plenum pressure of the valve was 5 atm. Two ion pinhole
cameras were installed in the axial and the radial directions. Track detector (Baryotrak-P) was used for detecting the
ions.
When positive voltage was applied to the center conductor, a coaxial structure of ion emission was observed in
the axial direction. The ions on the axis were observed with 1.5 µm aluminum foil, and the ions of peripheral were not
observed with 0.8 µm aluminum foil. When negative voltage was applied to the center conductor, the ions were
observed only on the axis in the axial direction. These observations indicate that high-energy ions about 2 MeV
are emitted on the axis regardless of the current direction.
References:
K. Takasugi and E. Kiuchi, “Hard X-Ray Radiation from a Z-Pinch with Divergent Gas-Puff”, Plasma Fusion
Res. Vol. 2, 036, 2007.
[2] M. Nishio, H. Sakuma and K. Takasugi, “Ion Acceleration Independent of the Electric Current Direction in ZPinch Plasma”, Plasma Fusion Res. Vol. 6, 1201009, 2011.
[1]
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-62
Recovery Time of Laser-Triggered Z-pinch Discharge Plasma for Highly
Repetitive EUVL Source
Takashi Kamohara1, Soowon Lim1, Seiya Kitajima1, Lu Peng2, Sunao Katsuki3 and Hidenori Akiyama3
1) Graduate School of Science and Technology, Kumamoto university, Kumamoto, 860-8555, Japan
2) Civil Aviation University of China, Tianjin 300300,China
3) Institute of Pulsed Power Science, Kumamoto university, Kumamoto, 860-8555 Japan
Extreme ultraviolet (EUV) source is an important key to achieve an industrial application in the EUV
lithography. Currently, laser-triggered discharge (LTD) tin plasma is one of the promising discharge produced
plasma EUV source scheme [1-3]. The main challenges are operating at several tens of kilowatts electrical input
power and repetition rates of up to and beyond ten kilohertz, adequately cooling the electrode system, mitigating debris,
and maintain a reasonable system lifetime [4-6]. We present a post-discharge study of a laser-triggered vacuum
discharge for high repetition rate EUV source. The insulation strength between electrodes was measured by time lapse
electrical breakdown voltage measurement. Experimental results show that the insulation strength is recovered slowly
when the larger charging energy of capacitors and quickly when shorter gap of electrodes. In addition, the two-laser
triggered discharge system was built to model the high frequency operation of the laser-triggered discharge plasma
EUV source. The intensity recovery process of EUV radiation with different discharge time intervals was measured.
Recovery of EUV radiation was slower than the electrical recovery for both of 2.5 mm and 5 mm gaps. In case of 4
J charging energy, EUV intensity of second discharge recovered same intensity as first discharge at the time after about
250 μs and 70 μs for 5 mm and 2.5 gap distances respectively. Time relation between two recovery processes of
electrical insulation strength and EUV radiation has been discussed for the estimation of optimal frequency in
our LTDPP EUV source.
References:
[1]
[2]
[3]
[4]
[5]
[6]
Jos Benschop, "EUV: Status and Challenges Ahead", presented at the 2010 International Workshop on EUV
Lithography, Maui, Hawaii, USA, Jun. 21-25, 2010.
V. Bakshi, "Status and Future of High Power EUV Source Technology", presented at the 2010 International
Workshop on EUV Lithography, Maui, Hawaii, USA, Jun. 21-25, 2010.
Vadim Banine, "EUV Lithography and EUV Sources", presented at the 2011 International Workshop on EUV
and Soft X-ray Sources, Dublin, Ireland, Nov. 7-10, 2011.
K. Suzuki et al., "Joint Requirements for EUV Source", EUV Symposium, Prague, Oct. 19, 2009.
G. Schriever, O. Semprez, J. Jonkers, M. Yoshioka, R. Apetz, “Laser-produced plasma versus laser-assisted
discharge plasma: physics and technology of extreme ultraviolet lithography light sources”, J.
Micro/Nanolith. MEMS MOEMS, Vol. 11(2), pp. 021104, 2012.
M. Benk, K. Bergmann, “Brilliance scaling of discharge sources for extreme-ultraviolet and soft x-ray
radiation for metrology applications”, J. Micro/Nanolith. MEMS MOEMS, Vol. 11(2), pp. 021106, 2012.
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-63
Tunable Narrowband Soft X-ray Sources with Laser-produced High-Z Plasmas
Hayato Ohashi*1, Hiroaki Ito1, Yuhei Suzuki2, Goki Arai2, Bowen Li3, Gerry O’Sullivan4, Fumihiro
Koike5, Chihiro Suzuki6 and Takeshi Higashiguchi2
1) Graduate School of Science and Engineering for Research, University of Toyama, Toyama, Toyama 930-8555,
Japan
2) Department of Advanced Interdisciplinary Sciences and Center for Optical Research and Education (CORE),
Utsunomiya University, Utsunomiya, Tochigi 321-8585, Japan
3) School of Nuclear Science and Technology, Lanzhou University, Lanzhou, 730000, China
4) School of Physics, University College Dublin, Belfield, Dublin 4, Ireland
5) Faculty of Science and Technology, Sophia University, Chiyoda, Tokyo 102-8554, Japan
6) National Institute for Fusion Science, Toki, Gifu 509-5292, Japan
The development of plasma light sources has been attracted attentions for many applications, especially for the
semiconductor lithography in the past decade. Laser-produced plasmas (LPPs) are powerful candidates as the light
source for the lithography in the extreme ultra-violet (EUV) region,
i.e. 13.5 and 6.x nm. These EUV light sources exploit the advantage that 4p64dN-4p64dN-14f +4p54dN+1 (n = 4n = 4) unresolved transition arrays (UTAs) in several charge states appear at almost same
wavelength in spectra from Sn- and Gd-LPPs. From this point of view, n = 4-n = 4 UTAs from LPPs of other
elements could provide light sources at other wavelengths for other applications such as x-ray microscopy in the
water window, 2.3–4.4 nm, and the carbon window, 4.4–5.0 nm. In early experimental studies with other elements,
previous-generation ns-lasers were used resulting in forming optically thicker LPPs than ps-LPPs. It is known that
optically thick plasmas can strongly self-absorb resonance line emission. Optically thin plasmas thus provide more
efficient light sources. Therefore, systematic LPP studies with up-to-date intense ps-lasers are needed to determine
available light source wavelengths for future applications.
We show the atomic number, Z, dependence of the emission wavelength of strong resonance UTAs of
neodymium-doped yttrium aluminum garnet ps-LPPs for elements with Z = 50–83. It can be expressed in a
quasi-Moseley’s law [1]. Moreover, the peak wavelength of a UTA can be shifted a little by tuning the electron
temperature, i.e. the charge state distribution, of the LPP [2]. Experimental and theoretical analyses of observed
LPP spectra are also shown with an electron beam ion trap experiments and the flexible atomic code
calculations.
ohashi@eng.u-toyama.ac.jp
References:
[1]
H. Ohashi et al., “Quasi-Moseley’s law for strong narrow bandwidth soft x-ray sources containing higher
charge-state ions,” Appl. Phys. Lett. (accepted).
[2] H. Ohashi et al., “Tuning extreme ultraviolet emission for optimum coupling with multilayer mirrors for
future lithography through control of ionic charge states,” J. Appl. Phys., Vol. 115, pp. 033302, 2014.
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-64
Foil-less Plasma-filled Diode
A.A. Zherlitcyn*, B.M. Kovalchuk and N.N. Pedin
Institute of High Current Electronics, 634055 Tomsk, Russia
Electron beam generation occurs in a plasma-filled diode in a double sheath with plasma as an anode boundary.
Implementation of the plasma anode provides possibility to exclude the anode foils or grids, separating regions of the
beam generation and transportation to target. Ion flow from the diode region to the transport area removes limit on
the beam current by its own space charge.
This report presents experiments on generation and transport of the electron beam in the plasma- filled
diode on base of capillary gun without the metal anode electrode before the transportation region. Beam parameters
and transport conditions depend on parameters of preliminary generated ion flow before a main voltage pulse.
The ion flow was investigated with Faraday cup in combination with frame photography by CCD camera with
6
3 ns resolution. Plasma bulk velocity is ~10 cm/s, which corresponds to plasma temperature in units of eV. Besides
it ion flow has been observed with velocities about an order higher. This flow can be used for space charge
neutralization at the electron beam transport.
Plasma filled diode with 130 kA current and 0.5 MV voltage has been realized in experiments on linear
transformer driver. Beam current was measured in the transport area behind the plasma anode. At preliminary
injection time of the plasma in 1 µs electron beam with 100 кА current moves almost without losses on distance up
to 10 cm. At larger distance beam is getting lost partially and on 30 cm distance beam current is about 40% from the
initial one.
Diode geometry without anode foils or grids is promising for relativistic microwave generators on GW power
level.
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-65
Plasma-filled Diode Power Increase
A.A. Zherlitcyn*, B.M. Kovalchuk and N.N. Pedin
Institute of High Current Electronics, 634055 Tomsk, Russia
Power of the plasma-filled diode in high-voltage phase is determined by the driving circuit parameters
and transition diode resistance. In case of inductive storage with inductance L, charged by current I0 , assuming
linearly rising resistance R(t) = k ⋅ t the power can be defined as P ∝ I0 2 k ⋅ L . Problem of the power rise can be
solved by increase of the stored energy in the circuit inductance provided that transition diode resistance is holding
constant.
In experiments on the linear transformer driver (53 nF, 480 kV) the possibility has been checked out for such
increase of the stored energy at holding on the transition diode resistance and diode current increase at fixed
parameters of the plasma bridge. Current increase from 100 to 180 kA was obtained by increase of the current rise
rate from 0.9 to 1.7 kA/ns at respective change of the circuit inductance from 420 to 200 nH. Stored energy has
been increased respectively from 2.1 to 3.2 kJ. Time of the energy transfer into the circuit inductance was on the
same level of 120 ns.
Holding on the transition diode resistance in high-voltage phase on level of 0.5 Ω/ns has been shown at more
than 1.5 times diode current increase. Diode power has been increased 1.6 times from 100 to 160 GW. Since
current and power rise were provided by change of the circuit inductance, diode voltage amplitude was almost
the same about 1 MV. The latter can be explained by increase of the current output rate from the circuit inductance
in high-voltage phase.
Further increase in power of the plasma-filled diode has been obtained by rise of generated voltage. In order
to decrease the current drop in high-voltage phase the driver circuit was made as Marx generator with coaxial
water line (5.3 Ohm, 56 ns, 1.5 MV), providing current input of 150 kA into the 500 nH inductance in 120 ns. Stored
energy in the inductance was about 5.6 kJ. This circuit models LTD with MV level output voltage. The following
diode parameters were obtained: 150 kA, 1.7 MV, 250 GW at holding on the transition diode resistance on level of
0.5 Ω/ns.
The experiments prove holding on the resistance rise rate of the plasma filled diode at increase of the stored
energy 2.5 times in the inductance. It allows to guess on the further scaling of the electron source on base of
plasma-filled diode.
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-66
Charge and Flux Control of Laser-Ablation Plasma for Stable Ion Beam
Extraction
Satoru Kanamaru*, Jun Hasegawa, Koya Hiraide, Mitsuo Nakajima and Kazuhiko Horioka
Department of Energy Sciences, Tokyo Institute of technology, Yokohama, Japan
In heavy ion fusion (HIF), one of the crucial issues is the development of an ion beam injector
that can supply a high-current (~0.5 A) heavy ion beam to the driver accelerator for long pulse duration
(~20 µs). For such a high-current injector, Kwan et al. proposed a merging multibeamlet extraction
scheme [1]. Compared with the conventional large-aperture beam extraction, this scheme enables us to
flexibly design a relatively compact injector with optimized beam optics. In addition, it is expected to
be applicable to various types of plasma sources.
The laser-ablation plasma has the potential to supply a large amount of heavy ions to the beam
injector because of its high-density nature. However, it is generally difficult to stably extract an ion
beam from the laser-ablation plasma because of the large fluctuation of the plasma ion flux and the
low purity of the ion charge state. The same difficulty arises also when we adopt the laser-ablation plasma
for the merging-multibeamlet type injector. To avoid this problem the stabilization and chargepurification of the laser-ablation plasma are needed. The purpose of our study is to examine the
possibility of the charge and flux control of the laser- ablation plasma by static/dynamic magnetic fields.
To analyze the effects of the magnetic fields on the charge and flux of the laser-ablation plasma,
we have developed a single-shot charge state analyzer, which can observe the ion flux waveforms for
various charge states simultaneously. The schematic diagram of the analyzer is shown in Fig. 1. A
-2
temporally changing transverse electric field E(t) ∝ t , where t denotes time, is applied to a collimated
ion flow so that ions having the same charge state can be deflected to a unique orbit independently of
the ion velocity. The ion flux of various charge states are measured separately with multiple ion
detectors located downstream. Compared with the conventional electrostatic charge state analyzer [2],
the single-shot charge state analyzer has the advantage that the charge state distribution and the ion flux
waveform are directly obtained with a single laser shot without complex and time-consuming data
processing.
This paper presents experimental results from a series of experiments that examine the effect
of external static/dynamic magnetic fields on rapidly expanding laser-ablation plasmas produced from
various target materials. The strategy to obtain a plasma flow suitable to stable beam extraction is
discussed.
Figure 1. A schematic diagram of the single-shot charge state analyzer.
References:
J. W. Kwan et al., “Ion Sources and Injector for HIF Induction Linacs”, Nucl. Instrum. and Methods A
464, p. 379-387 (2001).
[2] F. J. Allen, “A Plane Electrostatic Analyzer for Laser Produced Plasma Studies”, Review of Scientific
Instruments, VOL.42, NO.10(1971).
[1]
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-67
Self-biased Voltage to Suppress Secondary Electrons by a ZnO Resistor in a
Neutron Generator
Zhen Yang*, Jie Li, Jidong Long, Chaohui Lan, Yufei Peng, Tao Wang, Pan Dong and Ping Liu
Institute of Fluid Physics, CAEP, P. O. Box 919-106, Mianyang 621900, China
It is important to suppress the secondary electrons in neutron generators especially for compact sealed tube
neutron generator. Large amount of electrons will waste most of power, affect the insulation withstand of the device,
and meanwhile affect the neutron yield and waveform. Several methods with their advantages and disadvantages
to suppress the secondary electrons are compared and discussed in the text. An idea which uses a ZnO non-linear
resistor to provide constant self-biased voltage was introduced. The V-I curve for the ZnO non-linear resistor was
measured in the experiment. The effect for suppressing secondary electrons was tested with two kinds of electro circuits.
The result is that the secondary electrons are suppressed effectively and meanwhile not increase the volume and the
component of the device. It is most applied in compact sealed tube neutron generators.
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-68
Development of Intense Pulsed Ion Beam Source Using Bipolar Pulses
Keito Okajima*, Kazuki Kitajima, Hayato Ohashi and Hiroaki Ito
Graduate School of Science and Engineering, University of Toyama, Toyama 930-8555, Japan
An intense pulsed ion beam (PIB) has been actively studied as an energy driver of inertial confinement
fusion. The multistage liner induction accelerator has been developed to accelerate high energy and high current
pulsed ion beam. However, many large iron cores are utilized in the accelerator, which makes the accelerator
complicated and expensive. A new type of a pulsed ion beam accelerator named “bipolar pulse accelerator (BPA)”
has been proposed as the substitute for the induction linac. In the BPA, bipolar pulses are utilized and pulsed ion
beams are accelerated electrostatically. The BPA consists of a grounded ion source, a drift tube and a grounded
cathode, so the system is simple. Thus, BPA is suitable to post-accelerate low energy PIB. In addition, the merit
of the BPA is that the ion purity of the PIB is improved. Recently, PIB is expected to be applied to materials
processing including pulsed ion beam implantation, surface modification, and thin film deposition. For those
materials processing applications, it is very important to develop the accelerator technology to generate ion beams
with various ion species and high purity.
To realize the proposed accelerator BPA, a double coaxial type bipolar pulse generator and a prototype of
the BPA system were developed [1,2]. The bipolar pulse generator consists of a Marx generator and a pulse forming
line (PFL) with a rail gap switch on its end. The system utilizes a magnetically insulated acceleration gap. A
coaxial gas puff plasma gun was used as an ion source, which was placed inside of the grounded anode. When the
bipolar pulse with voltage of V-out = -110 kV and V+out = 80 kV and pulse duration of about 70 ns was applied to the
drift tube, in the 1st gap the ions were successfully accelerated from the grounded anode to the drift tube by the
2
negative pulse of the bipolar pulse. The pulsed ion beam with current density of 70 A/cm and pulse duration
of ≈ 50 ns was obtained at 48 mm downstream from the anode surface. The energy spectrum of the ion beam was
evaluated by Thomson Parabola spectromer. The ion energy was in reasonable good agreement with the
acceleration voltage, i.e., 1st pulse (negative pulse) voltage V-out of the bipolar pulse.
References:
[1]
K. Masugata, Y. Shimizu, Y. Fujioka, I. Kitamura, H. Tanoue and K. Arai, “Development of Bipolar-pulse
Accelerator for Intense Pulsed Ion Beam Acceleration”, Nucl. Instr. and Meth. Phys. Res., Vol.A535, pp.614621, 2004.
[2] H. Ito, K. Igawa, I. Kitamura and K. Masugata, “Bipolar pulse generator for intense pulsed ion beam
accelerator”, Rev. Sci. Instr. Vol. 78, pp.013502-1 - 013502-5, 2007.
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-69
Generation and Measurement of High Intensity X-rays
Yuji Kimura, Taichi Sugai and Weihua Jiang
Extreme Energy-Density Research Institute, Nagaoka University of Technology, Nagaoka, 940-2188, Japan
Efforts to prevent terrorism in ports and airports have been active since the September 11 attacks. In particular,
establishment of measures to prevent terrorism by fissile material that can be used in weapons of mass
destruction is an urgent need. Therefore, techniques which discover smuggling of nuclear material by air transport
or marine transport are required. Currently, a technique of nuclear material identification using X-rays has been
investigated. Irradiating X-rays to nuclear materials causes the fission generating neutrons and γ-ray spectrum.
Therefore, the nuclear materials are identified by measuring neutrons and γ-ray spectrum which are generated by
X-rays. We are considering the discovery of nuclear material by this method.
We propose irradiating X-rays generated from the accelerator as a technique for nuclear material finding.
In the present study, the instrument for measuring X-rays and the accelerator mechanisms are investigated. A
radiation measurement device using a scintillator was developed in order to easily measure the time variation of
the intensity of X-rays. Here, waveforms of high intensity pulse X-rays generated from the accelerator using
repetitive pulsed-power generator “ETIGO-IV” were measured. Peak of the obtained X-ray’s time-varying waveform
agreed with the inverse square law.
This measuring instrument technique is a major step for detection of nuclear material by high intensity
pulse X-ray generated by accelerator.
References:
[1]
C. L. Melcher, S. Friedrich, M. A. Spurrier, P.zupryczynski, R. Nutt, Cerium oxidation state in
LSO:Cescintillators, IEEE, 14th International Workshop on Room-Temperature Semiconductor X- and
Gamma-Ray Detectors, 2004
[2] Harold Rothfuss, Larry Byars, Michael E. Casey, Maurizio Conti, Lars Eriksson, Christian Michel,Energy
resolution and absolute detection efficiency for LSO crystals: A comparison between Monte Carlo
simulation and experimental data, Nuclear Instruments and Methods in Physics Research Section A
Accelerators Spectrometers Detectors and Associated Equipment 2007, 1087-1092
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
P2-70
High Voltage Power Supplies for 30kW 95GHz Gyrotron
Suk-Ho Ahn*1, Hong-Je Ryoo2, Sung-Roc Jang2 and Jong-Soo Kim2
1) Dept. of Energy Conversion, University of Science & Technology, Chang-won, Korea
2) Electric Propulsion Research Center, Korea Electrotechnology Research Institute, Chang-won,Korea
This paper describes the implementation and test of the power supplies including cathode power supply (CPS),
anode power supply (APS), body power supply (BPS) and Heater power supply (HPS) with following
specifications for driving a 30 kW 95GHz gyrotron. - CPS: -50kVmax, -2Amax, 3 Second, 1% output ripple,
EArc<10J, - APS: -50kVmax, -10mAmax, 1% output ripple, - BPS: 25kVmax, 10mAmax, 1% output ripple, - HPS:
12Vmax, 5Amax, 50kV Isolation. To lower a ripple, a method that increases the switching frequency or output
filter value can be used. However, it limits the increase in switching frequency owing to a switching loss that is
generated by semiconductor devices. On the other hand, raising the output filter capacitor allows the output voltage
ripple to be minimized. But, when arc occurs, all of the energy stored in the output filter capacitor is transmitted
to the load side, and the load can get damaged [1]. In order to satisfy the requirements about it of CPS, the multiphase resonant converter was proposed and it was designed for reducing output voltage ripple with minimized
output filter component which is closely relate with arc energy. For three auxiliary power supplies, APS, BPS
and HPS, single-phase resonant converter with MHz switching frequency is adapted to takes advantages of
the low ripple, high-efficiency, and high-power density [2]. Based on high-efficiency resonant converter topology,
the design and implementation of these power supplies are presented. And, various experimental results that
verify the reliability and superiority are shown. In addition, the control of three power supplies including
feedback voltage control, interlocks, and protections for gyrotron are also described.
Fig. 1. Experimental waveforms of High Voltage Power Supplies for 30kW 95GHz Gyrotron
References:
[1] Lohr, John, et al. "Practical experiences with the 6 gyrotron system on the DIII-D tokamak." Fusion
Engineering, 2003. 20th IEEE/NPSS Symposium on. IEEE, 2003.
[2] Suk-Ho Ahn; Ji-Woong Gong; Sung-Roc Jang; Hong-Je Ryoo; Duk-Heon Kim, "Design and Implementation
of Enhanced Resonant Converter for EV Fast Charger" Journal of Electrical Engineering & Technology ,
vol.9, no.1, pp.143,153, Jan. 2014
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
OA4-1
Optimization of Pulsed Electron Beam Facilities (GESA) by PIC-3D Simulations
Georg Mueller and Wladimir An
Karlsruhe Institute of Technology (KIT), Institute for Pulsed Power and Microwave Technology (IHM), Hermann-vonHelmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
For at least 2 decades a large body of research has shown that microsecond intense electron beams (MIEB) can
be successfully applied for enhancement of such properties of materials like corrosion and wear resistance, micro
hardness, surface polishing, breakdown electrical field strength, etc. For realization of these applications electron
beams with corresponding parameters are required, such as power density of 0.5 - 6 MW/cm2, electron kinetic
energy 50 - 400 keV, pulse duration 10 – 200 µs with a cross-sectional area, which has to be adapted to the particular
application. However, further system optimizations are required to ensure reliable beam transport and homogenous
energy distribution at the target. In these paper recent results of simulations for triode type pulsed electron beam
facilities of GESA-type are presented. The commercial MAGIC 3D code, an electromagnetic particle-in-cell code,
has been applied to investigate beam performance. Based on this results suggestions on accelerator design are
discussed, e.g. additional electrode in the second triode gap to prevent potential well or even virtual cathode
formation or reduction in aspect ratio (length/radius) in radial converging electron beam facilities, enabling a
significant improved energy distribution along the tubular target.
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
OA4-2
Ion Component Diagnosis of Metal Hydride Cathode Vacuum Arc Ion Source
Chaohui Lan*, Le Zheng, Jidong Long, Yufei Peng, Jie Li, Zhen Yang and Pan Dong
Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang, 621900, P.R. China
Metal hydride cathode vacuum arc ion sources can produce microsecond to millisecond intense pulsed
proton beams, which are applied in many areas, such as accelerator injection and ion implantation. Generally, the
ion components in metal hydride cathode vacuum arc are complicated and consist of numerous metal and nonmetal
ions with different charge states. In this paper, we firstly review the methods and devices for ion component
diagnosis of vacuum arc ion source used by former researchers. Then the technical features of a home-made
orthogonal-injection time-of-flight mass spectrometer are introduced. By using this spectrometer, the ion
components and their charge state distributions at different discharge moments are presented. The evolutions of
different ion components with time are also given.
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
OA4-3
Cathodes Ablation Analysis on Cold-cathode H- PIG-Type Ion Source
Jidong Long*1, Cui Yuntao2, Zhen Yang1, Pan Dong1, Xiaozhong He1 and Kaizhi Zhang1
1) Institute of Fluid Physics (IFP), China Academy of Engineering Physics(CAEP), P.O. Box 919-106, Mianyang
621900, China
2) Beijing General Research Institute of Mining and Metallurgy,Beijing,102206,China
Research progress on the cold-cathode negative hydrogen Penning Ion Gauge (PIG) type ion source is
presented which is served as the internal ion source of a 11MeV cyclotron at IFP. Recent works are focused on how
to prolong the cathodes working life. H- penning source works relying on arcing discharge resulting in strong
ion sputtering which is the main mechanism of the cathodes ablation. By analysis of the products of ablation，it is
found that the ablation speed could be quickened greatly if oxygen elements involving the discharge. Some possible
chemical reactions of oxygen are analyzed to explain the mechanism why ablation be quickened. By lowering
the contaminants amount in the hydrogen gas and choosing high purity cathodes material, the work life of
the cathodes could be increased greatly. Together with the efforts on reducing the power consumption of the ion
source, the working life of the source could reach 60 hours now,8 times longer than before.
Keywords: negative hydrogen, ion source, penning gauge, ion source, arc discharge, electrode ablation
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
OA4-4
Numerical and Theoretical Studies on Equipartitioning of Longitudinal and
Transverse Temperatures during Pulse Compression in Compact Simulator for
Heavy Ion Inertial Fusion
Takashi Kikuchi*1, Yasuo Sakai2, Jun Hasegawa2, Kazuhiko Horioka2, Kazumasa Takahashi1, Toru
Sasaki1 and Nob. Harada1
1) Nagaoka University of Technology, Nagaoka 940-2188, Japan
2) Tokyo Institute of Technology, Yokohama 226-8502, Japan
⊥
In an energy driver of heavy ion inertial fusion, a longitudinal pulse compression scenario is a key issue
for an effective implosion process of a fuel pellet. Although several types of the accelerator complex were
proposed [1], the extreme pulse compression is needed in the final stage of energy driver with either approach. A
large scale of particle accelerator is required to generate an intense heavy ion beam, however it is not suitable
for the investigation of beam dynamics from the viewpoint of cost. For this reason, an experimental device by
using electron beams was proposed for a scaled simulator [2]. It is easy to achieve the space-charge-dominated
state in a small experimental device.
In the space-charge-dominated beam, the energy dissipation between the longitudinal and transverse
directions is an important mechanism for the beam transport. The equipartitioning condition can be evaluated
2
with the ratio of the transverse and longitudinal temperatures T⊥ / T|| = [ 𝛾𝛾b εn⊥ zm / (εn|| rb) ] , where T⊥ and
T|| are the temperatures for transverse and longitudinal directions, 𝛾𝛾b is the relativistic factor, εn⊥ and εn|| are
the effective normalized emittances for transverse and longitudinal directions, zm is the half bunch length (=
1/2
1/2
5 zrms, where zrms is the rms half bunch length), and rb is the effective beam radius (= 5 rrms, where rrms is
the rms beam radius) [3,4].
The kinetic energy of electron beam is 2.8 keV, and the pulse duration is 100 ns [2]. The initial effective
beam radius is estimated as 0.626 mm, and the initial half bunch length is given by 1.56 m [5]. After the pulse
compression, the effective beam radius is estimated as 1.01 mm, and the half bunch length is given by 0.15 m at
the maximum compression point [5]. The transverse and longitudinal temperatures are assumed by T⊥= T|| = 1000
K. As a result, the ratio of the transverse and longitudinal temperatures is estimated as T⊥ / T|| = 0.00285 by the
above equipartitioning equation.
Figure 1 shows the calculation result with the
experimental conditions [2] using a multi-particle
simulation code [5]. As shown in Fig.1, the ratio of
the transverse-longitudinal temperatures of beam bunch
is decreased during the pulse compression due to the
head-to-tail velocity tilt applied with the modulation
voltage. During the pulse compression manipulation,
T⊥ / T|| is increased due to the space- charge effect,
and the ratio is evaluated by T⊥ / T|| = 0.01 after the
compression as shown in Fig.1. In comparison with the
theoretical and numerical results, it is implied that the
discrepancy is caused by the nonlinear space charge
effect.
Fig. 1: Ratio of transverse-longitudinal temperatures
obtained by multi-particle simulation result.
References:
[1] J.J. Barnard, et al., Nucl. Instrum. Methods Phys. Res. A415, p.218, 1998.
[2] Y. Sakai, et al., Nucl. Instrum. Methods Phys. Res. A733, p.70, 2014.
[3] M. Reiser, Theory and Design of Charged Particle Beams, John Wiley & Sons, Inc., Appendix 4, p.574,
1994.
[4] R.A. Jameson, IEEE Trans. Nucl. Sci. NS-28, p.2408, 1981.
[5] T. Kikuchi, et al, to be published in Prog. Nucl. Energy.
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
OA4-5
Characterization of Carbon-fiber-aluminum Cathodes for High Power
Microwave Generation
Jinchuan Ju*, Dan Cai, Lie Liu, Yuwei Wang and Jiande Zhang
College of Optoelectronic Science and Engineering, National University of Defense Technology, Chnagsha 410073, P.
R. China
Explosive emission cathodes are widely used in various applications such as high power microwave generators,
free electron lasers and long-distance radars, owing to their super-capacity to provide high current density of the order
2
of kA/cm . However, the use of explosive emission cathodes is limited by cathode plasma expansion which can result
in diode gap closure, impedance collapse, and shortening of the produced high power microwave pulses.
In this work, we report on the characterization of thermal plasma expansion during the operation of a high power
diode with an explosive emission carbon-fiber-aluminum (CFA) cathode [1] driven by a 250 kV, 150 ns accelerating
pulse. It is found that a quasi-stationary state of plasma expansion is obtained during the main part of the
accelerating pulse and the whole plasma expansion exhibits an
``U''-shape velocity evolution. Furthermore, joint functions of the cathode and anode plasma expansions lead
to the higher diode closure speed at the end of the accelerating pulse. A theoretical model describing the dynamics
of plasma expansion is developed, which indicates the plasma expansion velocity is determined by equilibrium
between the diode current density and plasma thermal electron current density. The presented conclusions are beneficial
for future improvement of explosive emission cathode design.
References:
[1]
L. Liu, L. Li, J. Wen, and H. Wan, “Robust, easily shaped, and epoxy-free carbon-fiber-aluminum cathodes for
generating high-current electron beams”, Rev. Sci. Instrum., Vol. 80, pp. 023303, 2009.
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
OA4-6
MITL Experiments on a 10-Stage LTD System
Zou Wenkang*, Guo Fan, Zhang Le, Chen Lin, Wang Meng, Xie Weiping and Deng Jianjun
Key Laboratory of Pulsed Power, Institute of Fluid Physics, China Academy of Engineering Physics, P.O.Box 919-150,
Mianyang 621999, China
A series of electron beam diode experiments were conducted on a 10-stage linear transformer driver (LTD)
system, which was aimed for investigations on the magnetically insulated voltage adder and pulse transmission.
By changing the anode-cathode distance, cathode material and emission area width, different diode impedance
histories were realized, and then a wide voltage span, i.e. 0.5~1.0 MV, was derived for the LTD system. In this
paper, the influence of diode configuration on its impedance characteristics and magnetic insulation, as well as
the system performance, will be described.
Key words: linear transformer driver; magnetic insulation; e-beam diode.
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
OA4-7
Beam Interactions with Surface Waves and Higher Order Modes in Oversized G-­‐band Slow-­‐Wave Structure Kazuo Ogura*, Akihiro Shirai, Masahiko Ogata and Kiyoyuki Yambe Graduate School of Science and Technology, Niigata University, 950-­‐2181, Japan Smith-Purcell free electron laser (SP-FEL) and backward wave oscillator (BWO) have been studied
extensively to obtain high frequency and high power electromagnetic waves. These devices have a
slow-wave structure (SWS) with periodically corrugated walls. In SP-FELs, electron beams pass near
the grating and directly excites the radiating wave. Original SP radiations was a spontaneous emission
and relatively weak [1]. Stimulated and superradiant SP radiations have been studied to develop
compact terahertz wave sources [2]. For the superradiant SP radiations, beam bunching is required and
is provided by the interaction with the surface wave of grating. In BWO, the SWS is oversized with a
diameter larger than the free-space wavelength of output electromagnetic wave to increase the
operation frequency. In the oversized SWS, slow waves are concentrated on the corrugated walls and
become surface waves. BWO operations occur with the surface wave having negative group velocity.
Up to now, the surface wave and the higher order mode have been studied separately. However, it is
very natural that they coexist in periodic SWS [3, 4].
In this work, we present numerical study on beam interactions with the surface wave and the higher
order mode in oversized G-band SWS. Since the surface waves are concentrated very close to the
corrugations, their analysis becomes very difficult due to numerical divergences in calculation
processes. Moreover, many waveguide modes exist in the oversized SWS and the mode competition
becomes a serious problem. To reduce this problem, double or coaxial SWS may be used as an
alternative to hollow SWS. A numerical code has been developed for hollow and coaxial
configurations based on the modulated boundary of annular beam, considering vertical beam
perturbations as well as longitudinal ones [5]. The beam interactions with the three-dimensional
perturbations are analyzed in such a high frequency region as the G-band for the first time. The
vertical perturbation leads to the slow cyclotron interaction in addition to the conventional Cherenkov
interaction and becomes important by increasing the interaction frequency. The two interactions
become strong by increasing the beam current and merge for a sufficiently high beam current.
Controllability of higher-order mode of oversized SWS is examined using coaxial configuration. The
merged interaction and the higher order mode control presented in this work may be very attractive to
develop high-intensity THz wave sources.
References: [1] S. J. Smith and E. M. Purcell, "Visible Light from Localized Surface Charges Moving across a Grating," Phys. Rev., Vol. 92, p.1069, 1953. [2] D.Li, Z. Yang, K. Imasaki, and Gun-­‐Sik Park, “Particle-­‐in-­‐Cell Simulation of Coherent and Superradiant Smith-­‐Percell radiation”, Phys. Rev. ST Accel. Beams, Vol. 9, 040701, 2006. [3] K. Mizuno, S. Ono, and Y. Shibata, “Two Different Mode Interactions in an Electron Tube with a Fabry-­‐Perot Resonator-­‐ The Ledatron”, IEEE trans. Electron Devices, Vol. 20, pp.749-­‐752, 1973. [4] H.L. Andrews, C.A. Brau, and J.D. Jarvis, Observation of THz Evanescent Waves in a Smith-­‐ Purcell Free-­‐Electron LaserJ. Appl. Phys., Vol. 105, 024904, 2009. [5] K. Ogura, H. Yamazaki, Y. Kiuch, and Md.R. Amin, “Slow Cyclotron Instability due to Surface Modulation of an Annular Beam”, J. Plasma Phys., Vol. 72, pp.905-­‐908, 2006. EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
OB4-1
Exploring Potential Biomedical Applications of NsPEFs
Jue Zhang
Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China, 100871
The effects of pulsed electric fields on biological cells have been studied since the late 1950’s. More recently, the
duration of the electric fields has been shorten to the scale of nanosecond. Precedent researchers discovered that
nanosecond pulsed electric fields was able to induce a series of biological effects, including cell apoptosis, membrane
permeablization, platelet aggregation and intracellular calcium release. Based on these primary effects of nsPEFs,
following researchers developed more biomedical applications of nsPEF, such as tumor elimination. The mechanisms
underlying these phenomena attracted attentions from researchers in the area of engineering and biology. Electrical
models of biological cells and molecular dynamic analysis demonstrated that nsPEFs increased the probability of
electric field interactions with intracellular structure. Some cells signaling pathways that responded to nsPEFs stimuli
were also discovered.
The research on nsPEFs in Peking University focuses on expanding the range of applications of nsPEFs,
especially in cancer treatment and enhancement in proliferation. NsPEFs have been proved effective in breast cancer,
ovarian cancer, oral cancer and melanoma treatment. NsPEFs also have been applied in combination with
chemotherapy or molecular targeting therapy as an enhancement for the traditional therapies. For nsPEFs-induced
proliferation, exposure of nsPEFs resulted in early growth of plants, and enhanced proliferation in phenotypes of
chondrocytes.
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
OB4-2
Nanosecond Pulsed Electric Fields (nsPEFs) as a Novel Technology for
Improving Avermectins Production in Streptomyces Avermitilis
Jinsong Guo *1, Ruonan Ma 2, Shan Wu1, Bo Su2 and Jue Zhang 1,2
College of Engineering, Peking University, Beijing, China
Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
The avermectins are a complex of chemically related agents which used commercially in animal health,
agriculture and human infections [1]. They are produced by a species of actinomycete which named S.
avermitilis. However, there are still some disadvantages with using the wild-type strain to produce avermectins,
such as its low avermectins productivity and long fermentation time. In this study, nanosecond pulsed electric fields
(nsPEFs) was applied to induce mutations in S. avermitilis to improve the fermentation efficiency of avermectins.
In our experiment, the cell suspension of S. avermitilis was treated by nsPEFs. The cell viability and
morphological changes of S. avermitilis after nsPEFs exposure was evaluated by counting the colony forming
units (CFU) and scanning electron microscope (SEM) assays. The cell growth curves of S. avermitilis with and
without nsPEFs treatment were obtained by recording the optical density (OD) readings via Rapid UV/Vis
spectrometer. The yields of avermectin B1a and total avermectins were measured by high performance liquid
chromatography (HPLC). In addition, the PH and temperature of the liquid system after nsPEFs treatment are
monitored by the Microprocessor pH-meter and thermometer, respectively. The oxidation reduction potential
(ORP) of nsPEFs-treated liquid was monitored by standard electrode.
The results suggested that when 100 ns, 20 kV/cm, 100 pulses applied to S. avermitilis, the treated group
show much higher proliferation rate than control cells, and high productivity of avermectin was obtained. With the
advantage of short duration, high voltage, low energy and non-thermal effects [2], the nsPEFs has a good
mutagenic effect on S. avermitilis. Our results extend the frontier of nsPEFs in mutation breeding for
enhancement of avermectin production, and suggest that nsPEFs could be developed as a promising mutation
tool for the fermentation industry.
References:
Ikeda, H., & Omura, S. (1997). Avermectin biosynthesis. Chemical reviews, 97(7), 2591-2610.
Kolb, J. F., Kono, S., & Schoenbach, K. H. (2006). Nanosecond pulsed electric field generators for the study of
subcellular effects. Bioelectromagnetics, 27(3), 172-187.
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
OB4-3
Intracellular Oxidation is Responsible for Cell Death Induced by Nanosecond
Pulsed Electric Fields
Shan Wu1, Bo Su2, Jinsong Guo1, Jue Zhang1,2 and Jing Fang1,2
College of Engineering, Peking University, Beijing, China, 100871
Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
Nanosecond pulsed electric fields can induce a variety of biological effects, and has been identified as a
novel technique for tumor ablation. Existed theories for these biological effects include nanopore formation in
membrane, responses of mitochondria and calcium burst. However, the cellular responses to nsPEFs are so
complex that not all phenomena may be explained by established theories.
In the study, we demonstrate that nsPEFs stimulations trigger the production of reactive oxygen species
in multiple human cell lines without oxidation in cell-free buffers. Cells were treated with nsPEFs of 100ns
2+
duration at electric field intensity of 10~25kV/cm in D-PBS buffer with different Ca status, and reactive
oxidized species was determined by the oxidation of DCFH-DA. Lipid oxidation and formation of H2O2 were
also evaluated. To determine the source of oxidation, cell-free phosphate buffers were pulsed and the oxidationreduction potentials were assessed with an oxidation- reduction potentiometer. It is observed that nsPEFs triggered
2+
ROS production is Ca -dependent and associates with nsPEF-induced cell death. By scavenging ROS, cell
survival after pulse significantly increased. NsPEF triggered ROS production involves DNA fragmentation and
Bid-induced mitochondrial permeablization, which indicates that ROS might be an intermediate step in the process
of nsPEF-induced cell death. The study reveals another angle for explanations of nsPEF triggered bio- effects,
and may help understand the mechanisms of how nsPEF disrupts cells.
References:
O. Pakhomova, V. Khorokhorina, A. Bowman, R. Rodaitė-Riševičienė, G. Saulis, S. Xiao, A. Pakhomov,
“Oxidative effects of nanosecond pulsed electric field exposure in cells and cell-free media”, Arch. Biochem.
Biophys. 527(1), pp. 55-64, 2012.
R. Nuccitelli, K. Lui, M. Kreis, B. Athos, P. Nuccitelli, “Nanosecond pulsed electric field stimulation of reactive
oxygen species in human pancreatic cancer cells is Ca2+-dependent”, Biochem. Biophys. Res. Commun.
435(4), pp. 580-585. 2013.
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
OB4-4
Magnetic Fluid Hyperthermia to Treat HeLa Cells in Combination with
Nanosecond Pulsed Electric Fields
Shasha Zuo*1, Rui Zhang2, Ruixue Wang1, Jue Zhang1,2 and Jing Fang1,2
Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
College of Engineering, Peking University, Beijing, China
Hyperthermia using superparamagnetic iron oxide nanoparticles (SPIONs) has attracted increasing attentions due
to its encouraging antitumor effect. It has been proposed that comparing with extracellular hyperthermia, intracellular
hyperthermia exhibits efficacies in cancer therapy, which requires SPIONs as heating mediators incorporated into cell,
but yet to be proved [1]. In this study, nanosecond pulsed electric fields (nsPEFs) were introduced to treat the Human
cervical cancer cell (HeLa) before magnetic fluid hyperthermia, inducing more nanoparticles to penetrate into cell
membranes. It was clearly observed that there was a significantly increased cellular uptake of nanoparticles under
nsPEFs exposure with Prussian blue staining. The in vitro hyperthermia results also demonstrated the effectiveness of
the combination of nsPEFs and hyperthermia in HeLa cell treatment, which proves that intracellular hyperthermia was
superior to extracellular hyperthermia. Furthermore, the in vitro biocompatibility study of the nanoparticles was carried
out and the result revealed that these nanoparticles were found to have low toxicity. In conclusion, the proposed nsPEFs
based strategy could offer a convenient and valuable tool for the hyperthermia therapy.
References:
R.T Gordon, J.R Hines and D Gordon, “A biophysical approach to cancer treatment via intracellular
temperature and biophysical alterations”, Med Hypotheses, Vol.5, pp. 83–102, 1979.
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
OB4-5
Investigation of Bacterial Inactivation by Reactive Species Using Various Gas
Plasmas
Toshihiro Takamatsu*1,2, Kodai Uehara2, Yota Sasaki2, Hidekazu Miyahara2, Yuriko Matsumura3,
Atsuo Iwasawa3, Takeshi Azuma1, Masahiro Kohno3 and Akitoshi Okino2
Department of Gastroenterology, Kobe University, Kobe, Japan
Department of Energy Sciences, Tokyo Institute of Technology, Yokohama, Japan
Department of Bioengineering, Tokyo Institute of Technology, Yokohama, Japan
In recent years, atmospheric non-thermal plasmas attracted attention in medical field because of effective
and fast sterilization and wound treatment. It is considered that reactive species such as singlet oxygen, OH
radicals, and NO radicals generated by plasma have a vital relationship to the mechanisms. However,
conventional plasma sources are limited in their abilities to generate gas species. They can only generate air,
helium and argon plasmas, where these plasmas are relatively easy to generate. Therefore the reaction processes
and production amounts of reactive species are not yet well verified. Our group succeeded in developing a multigas plasma jet, which can generate plasma from various gas species. Using this plasma source, reactive
species can be investigated in detail, since they can be generated selectively by the supplied gas species. This
study aims to investigate the amount of reactive species generated by various gas plasmas and find reactive
species that can inactivate bacteria.
The multi-gas plasma jet can generate stable atmospheric plasma of various types of gas species such as
argon, oxygen, nitrogen, carbon dioxide and air at low gas temperatures. The body of the device is grounded
and an interior high-voltage electrode is connected to an AC power supply (Plasma Concept Tokyo, Inc.) of
16 kHz and 9 kV. The generated plasma flows through a 1-mm hole with a flow rate of 1 L/min. Each reactive
species, which were generated by various gas plasma, reacts with individual spin-trapping agents, and the spin
adducts can be identified using Electron Spin Resonance (ESR). The spin-trapping agents include 2,2,5,5Tetramethyl-3-pyrroline-3-carboxamide (TPC) as the singlet oxygen detector, 5,5-Dimethyl-1-pyrroline-N-oxide
(DMPO) as the OH radical and H radical detector, and N-methyl-D-glucamine dithiocarbamate iron (MGD-Fe)
as the NO radical detector. These agents were dissolved in a phosphate-buffered saline (PBS)(-) solution, with a
pH value of 7.5, and the concentrations of TPC, DMPO, and MGD-Fe were fixed at 75, 200, and 8 mM,
respectively. The solutions were treated with various gas plasmas, and spin adducts was measured using ESR.
As a result, carbon dioxide plasma generated the largest amount (90 µM) of singlet oxygen at 30 s, and nitrogen
plasma generated the largest amount (130 µM) of OH radicals. In addition, H radicals were generated with
argon, helium, and nitrogen plasmas. NO radicals were generated with nitrogen–oxygen plasma, and the largest
amount of NO radicals was generated at a 1:1 volume ratio.
7
To investigate bacterial inactivation effect, E. coli (ATCC25922) with a fixed population at 3.0 x 10 in
200 µL of PBS(-) was prepared, and the suspension was treated with each plasma. As shown in Fig. 1,
Nitrogen and carbon dioxide plasmas indicated a 7-log inactivation of E. coli within 60 s. In contrast, air,
argon, and oxygen plasma had a bacterial inactivation effect of less than one order of magnitude on E. coli
after 120 s. The measured quantity results are believed to be valid since the Escherichia coli inactivation effect,
as confirmed with the plasma treatment, yielded a large amount of singlet oxygen and OH radicals. The details of
the amount of reactive species and the bacterial inactivation will be presented.
Fig.1 E. coli inactivation by various gas plasmas
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
OB4-6
Investigation of Gas Flow Dependence of Plasma Jet Produced by Pulsed
Power
Akinori Yamamoto*1, Kosuke Asakawa2, Yuzo kawano1, Mizuki Nakai1
Toru Nakagawa3, Takashi Sakugawa2,3 and Hidenori Akiyama2,3
TAKAGI Co., Ltd., Kitakyushu-City, Fukuoka, 802-8540, Japan
2Graduate School of Science and Technology, Kumamoto University, Kumamoto-City, Kumamoto, 860-8555,
Japan
Institute of Pulsed Power Science, Kumamoto-City, Kumamoto, 860-8555, Japan
Non-thermal plasmas have been generated using repetitively operated pulsed power generators,
demonstrating the technology’s potential in creating discharges relatively easily at atmospheric pressure. Plasmas
have many applications such as surface modification of materials, treatment of exhaust gas, and sterilization of
medical equipment [1-3], and have thus grown increasingly important as a basic technology of production. A
further application of atmospheric pressure plasma is the sterilization of agricultural products [4]. Merits of
plasma for this latter use include that it does not require pesticide – instead requiring only an electric input – and
it can sterilize various bacteria types. However, the length of non-thermal atmospheric pressure plasma, at about
3 cm, is so short as to inhibit its workability. Therefore, extending plasma length is necessary to optimize this
application.
This paper investigates effect of gas flow velocity and gas concentration which affect plasma length under
dielectric barrier discharge. Helium gas was used for easy observance of light emission.
References:
A. Schutze, J. Y. Jeong, S. E. Babayan, J. Park, G. S. Swlwyn, and R. F. Hicks, “The Atmospheric-Pressure Plasma
Jet: A Review and Comparison to Other Plasma Sources”, IEEE Trans. Plasma Science, Vol. 26, No. 6, pp. 16851694, 1998.
C. Tendero, C. Tixier, P. Tristant, J. Desmaison, and P. Leprince, “Atmospheric pressure plasmas: A review”,
Spectrochimica Acta Part B, Vol. 61, No 1, pp. 2-30, 2006.
J. H. Choi, I. Han, H. K. Baik, M. H. Lee, D. Han, J. Par k I. Lee, K. M. Song and Y. S. Lim, “Analysis of sterilization
effect by pulsed dielectric barrier discharge”, Journal of Electrostatics, Vol. 64, pp.17-22 2006.
S. Iseki, T. Ohta, M. Ito, H. Kano, Y. Higashijima and M. hori, "Inactivation method of Penicillium digitatum
spores using non-equilibrium atmospheric pressure plasma : Investigation of inactivation factors", The
Institute of electronics,information and communication engineers IEICE Technical Report Jpn., OME, Vol. 109,
21-26, 2010
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference
Wednesday Afternoon, September 10, 2014
OB4-7
Biological Waste Reduction and Biogas Production Increase by Electrodischarge Treatment
Amit Izhar*, Yuri Liveshitz and Oren Gafri
Wadis Ltd., 3 Golda Meir st., Ness-Ziona 740-3648, Israel
This paper describes a new process for treating biological waste such as Waste Activated Sludge (WAS) that
forms as part of the treatment process at Waste-Water Treatment Plants (WWTP) serving municipal sewage works,
Pig farms, Food industry, etc.
These bio sludge can be converted into Biogas using biological processes in an Anaerobic Digester, to generate
energy, reduce carbon emission, and lower the volume of remaining waste, but this process demands very long
digestion times, imposed by the 1st digestion step, where the biological matter must first be broken down. Pretreatments that accelerate this step can greatly improve the efficiency, so that more Biogas is formed, Gas
composition improves, and digester Capacity/Volume is increased.
The Electro-Discharge process, that uses a pulsed power arc to generate a synergy of effects known to have a
beneficial effect on Anaerobic digestion, is compared with these known 1-effect processes - such as Ultrasonic
grinding, Electroporation, Peroxidation, and High pressure heating, etc. - in terms of total effectiveness and energetic
efficiency.
Lab and Beta-site results are discussed, as well as future Sub-Scale Plant tests now in preparation.
References:
H. Zhang, Sludge treatment to increase biogas production. Trita-LWR Degree Project 10-20. 2010.
B.E. Rittmann, H.S. Lee, H. Zhang, A. Jared, J.E. Banaszak & R. Lopez, Full-Scale Application of Focused-Pulsed
Pre-Treatment or Improving Bio-solids digestion and conversion to Methane, Water Sci. Technol. 58: pp. 18951901. 2008.
C. Bougrier, A. Battimelli, J.P. Delgenes & H. Carrere, Combined ozone pretreatment and anaerobic digestion
for the reduction of biological sludge production in wastewater treatment, Ozone-Sci. Eng. 29 (3): pp. 201–206.
2007.
C. Bougrier, J.P. Delgene`s & H. Carre`re, Combination of thermal treatments and anaerobic digestion to
reduce sewage sludge quantity and improve biogas yield. Process Safety and Environmental Protection,
84(B4): pp.280-284. 2006.
C. Bougrier, H. Carr`ere & J.P. Delgen`es, Solubilisaiton of waste activated sludge by ultrasonic treatment,
Chem. Eng. J. 106 (2): pp. 163–169. 2005.
U. Baier & P. Schmidheiny, Enhanced anaerobic degradation of mechanically disintegrated sludge. Water Sci.
Technol. 36 (11): pp. 137–143. 1997.
EAPPC2014 ‒ 5th Euro-Asian Pulsed Power Conference