Aidan Cowley (Presenting), Daragh Byrne, Sean Kelly
National Centre for Plasma Science & Technology (NCPST),
Dublin City University, Ireland.

• Fluorinated & Chlorinated gases are the most potent and longest lasting type of greenhouse gases emitted by human activities (CFC, HCFC)
Greenhouse Warming Potential (GWP) of significant greenhouse gases normalized to a comparative unit of CO
2
• In general, fluorinated gases are removed from the atmosphere only when they are destroyed by sunlight in the upper atmosphere via ionizing radiation.
• Previous work by a variety of groups and authors has shown that these long-lived greenhouse gases can be decomposed using plasma discharges in atmosphere.
• Additionally, generation of ozone is a frequent by-product of many ionising phenomena such as plasma discharges.
• The large scale adoption of such technology on the ground is hampered by the substantial energy requirements to strike and maintain such discharges for any appreciable effective timescale.
Climate Engineering Conference 2014, Berlin.

• Poses the question: are there any potential, non-environmentally damaging approaches to help reduce/mitigate the impact of these high GWP gases?
• We believe the SSP concept (Space Solar Power) is ideally suited to address this challenge:
- Represents a means of generating energy independently of any terrestrial source (i.e. does not directly contribute to emissions from within the troposphere (excluding fabrication & deployment costs))
- Targetable: vantage point in orbit allows for direction of beam to areas of greatest concentration, as determined by Earth observation satellites and ground stations. Also removes health issue of ionisation within the troposphere (and the associated health risks involved therein).
Climate Engineering Conference 2014, Berlin.

• SSP is candidate for future baseload utility power:
• Continuous power generation (in GEO 24/7/365)
• Non-depleting energy source (solar power)
• Minimal environmental emissions in product cycle
• Multi-TW capacity in final deployment stage
World oil reserves
(2012)
World proven oil reserves:
300 TW-years
• Interest in the US:
- ERDA/NASA studies in 1970-80s
- NASA, NSF, NRC, DoD, NSSO studies 1990/2000
- First commercial SSP incorporations in late 2000s
- First ‘real-life’ testing of SPS platform prototype at NRL (P. Jaffe et al, 2013)
• International interest: advances in
RnD industry partnerships:
- Japan (JAXA), Europe (ESA),
China (CNSA)
GEO
1 km
Solar energy received in
1km band at GEO per year:
310 TW-years
Climate Engineering Conference 2014, Berlin.

1. Use the SSP approach as a means of energy generation, ex-situ of our atmosphere
2. Use this power to induce plasma states at
targeted regions of the atmosphere using an appropriate technology
3. These regions will breakdown long-lived greenhouse gases via reaction chains, in turn helping mitigate environmental damage
Illustration showing SSP powered laser array targeting a region with a high concentration of atmospheric pollution in order to reduce the concentration via plasma decomposition
Two technologies are proposed which could conceivably allow for the formation of targeted plasma discharges within the atmosphere:
- Plasma Filamentation: Using solid state lasing and the formation of plasma filaments.
- RF Ionisation: Utilizing conventional RF antennae to heat & ionize the atmosphere
Climate Engineering Conference 2014, Berlin.

Utilize a competing linear/non-linear optical effect
Competing criteria of the focusing Kerr effect and the defocusing effect of the plasma on the laser beam results in the formation of a plasma filament
This approach allows for the propagation of over distances much longer than the Rayleigh length
The plasma discharge would generate ozone, via photoionization, excitation and dissociation of gaseous species within the targeted volume.
Terrestrial Tw Femtosecond
Filament Properties
Power Intensity 5 x 10 13 W/cm
10 15 – 10 16 cm 3 N e
(Electron Density)
Spectral Emission Range 230 – 1400 nm
[1] European Physical Journal – Applied Physics
The filamentation effect as the beam propagates through air results from a balance between Kerr-lens focusing and defocusing caused by the ionized plasma [1]
Photograph of a terawatt femtosecond laser pulse directed into the sky from the University of Jena.
The pulses form filaments of white light that can extend more than 20 km into the atmosphere
Climate Engineering Conference 2014, Berlin.

• Concentrations of ozone were measured in the volume surrounding the filament; both by experiments in the atmosphere and in controlled lab conditions.
• O
3 concentrations were measured to be in the parts per million range (ppm) and were typically found to be between 100 and 1000 times higher then the background atmospheric measurement.
• This is a significant ozone generation mechanism, attributed to the excitation interaction of the plasma discharge and the atmospheric gases.
• Largely immune to atmospheric turbulence, allowing for precise targeting of the filament within an atmospheric volume.
Time lapse CCD images from same experiment showing the
• Additionally, self-guided filaments generated by ultrashort laser pulses can assist water condensation, optical emission from the filament at ~20 km from the ground laser[1] even in undersaturated atmosphere conditions.
• May allow for the formation of clouds (compared to traditional seeding mechanisms), with a potential to change the atmospheric albedo (an additional geoengineering approach)
[1] J. Kasparian et al., “White-Light Filaments for
Atmospheric Analysis”, Science 301, 61, 2003.
Climate Engineering Conference 2014, Berlin.

Using high power RF heating of the atmosphere to generate diffuse plasma states at targeted altitudes (Mesosphereic & Stratospheric)
RF heating of the atmosphere has already been demonstrated by various authors since the late
1950s and is still under study by many terrestrial
RF heating facilities (i.e. Sura, SPEAR, HAARP, etc)
Ozone concentration modification using high power RF was reported by Kulilov et al [1] at heights of between 22 to 60 km at the the Sura
Ionospheric Heating Facility in Russia
The Phased Antenna Array at the
High Frequency Active Auroral Research Program,
Alaska, US.
[1] Yu. Yu. Kulilov et al, “Response of mesospheric ozone to the heating of the lower ionosphere by high-power HF radio emission”,
Geomagnetism and Aeronomy, 2013, Volume 53, Issue 1, pg 96-103 a
Climate Engineering Conference 2014, Berlin.

DCU atmospheric mass spectrometer for plasma discharge diagnostics
Lab/Ground Based Validation
• Using conventional plasma tool diagnostics to measure discharge byproducts, e.g. Ozone, etc
• Design or utilise existing low-pressure chambers to simulate upper atmosphere conditions
• Currently limited understanding of interactions of power beams with atmosphere
• Ground-based facilities have potential to significantly
exceed cost-efficiency and amount of data collected compared to orbital probes
• Ionosphere Research Facilities could provide extensive
capabilities to study atmospheric power beam interactions for ‘minimum’ first upgrade
• Could become first large-scale, concerted effort to establish comprehensive scientific knowledge of atmospheric power beam interactions
O
3 density vs distance to differential pumping
Aperture (Mass spectrometer)
Climate Engineering Conference 2014, Berlin.

• Ionospheric heating tests at HAARP (USA), Arecibo (Puerto Rico), etc. in
MHz range
MINIX (1986)
•
Two direct spacecraft-based investigations:
- Microwave-Ionosphere Nonlinear Interaction Experiment (MINIX):
Matsumoto, Kaya, Nagatomo et al., (1986)
- Microwave Energy Transmission in Space (ISY-METS):
Matsumoto, Kaya, Akiba et al. (1992)
- separated transmitter-receiver spacecraft flown in ionosphere
- transmitter ~2.4 GHz; RF power ~ 900 W
Limitations :
- narrow microwave beams (smaller than scale of power beams)
- limited RF power: beams probing immediate surroundings of spacecraft
- orbital motion: no continuous illumination of same atmospheric region
Lack of extensive data for microwave beam interaction with atmosphere
[1] Towards Space Solar Power - Examining Atmospheric Interactions of Power
Beams with the HAARP Facility, Leitgab M., Cowley A., IEEE Aerospace 2014. [2] Shinohara, Whitepaper: WPT for SPS; GaTech 2005
Climate Engineering Conference 2014, Berlin.

Modification of Type I-SPS Microwave beaming
Concept
- 2.45 ghz transmission of power or other nominal power transmission frequency for primary use
- Supplementary directional HF RF antenna which can be used as needed to target atmospheric volumes
Modification of Type II-SPS Laser Beaming
Concept
- Solid-state fs Lasing System (array)
- Owing to the specialty of the required lasing system, it might be optimum to deploy as a separate satellite
Type II
Type I

Summary:
• We propose a new approach to decomposing long lived greenhouse gases in an emission free approach using the SSP concept
• Orbiting SSP satellites would be used to generate ionising phenomena (this talk detailed two potential approaches)
Open Challenges:
• Ionisation rate as a function of RF power and local power density – is the effect sufficiently pronouced to have an impact at a local and (ultimately) global scale?
• Complexity of upper atmosphere interactions
• The propagating signal may be affected by its passage through the ionosphere (upper atmosphere) before reaching a target volume of pollution. These effects depend significantly on frequency, but include signal absorption, scintillation, Faraday rotation and bandwidth decoherence
Validation of Concept:
• Experimental measurement of atmospheric conditions at target heights via existing low-pressure gas chambers and interactions with ionising phenomena
• Much could be learned from existing low-pressure & atmospheric plasma models (species density, cross sections, lifetimes, etc)
Future Directions:
• Potential applications to bodies beyond our own planet, e.g. terraforming
• Could also used a as means of fundamental research into upper atmosphere, e.g.LIDAR, etc.
Climate Engineering Conference 2014, Berlin.

Aidan Cowley (Presenting)
National Centre for Plasma Science & Technology, Dublin City University, Ireland, cougaris@gmail.com
Daragh Byrne
National Centre for Plasma Science & Technology, Dublin City University, Ireland, daragh.byrne2@mail.dcu.ie
Sean Kelly
National Centre for Plasma Science & Technology, Dublin City University, Ireland,
Climate Engineering Conference 2014, Berlin.