Annual Moscow Workshop “Physics of Nonideal Plasma”
(PNP’2003)
(2-3 December 2003, Moscow, Presidium RAS)
ABSTRACTS
POSTERS
==========================================
1
STABILITY OF NEGATIVE IONS NEAR THE SURFACE OF A SOLID
D. I. Zhukhovitskii a, *, W. F. Schmidt b , and E. Illenberger b
a Joint
Institute for High Temperatures, Russian Academy of Sciences,
Izhorskaya ul. 13/19, Moscow, 125412 Russia
b Institut für Physikalische und Theoretische Chemie, Freie Universität Berlin D-14195,
Berlin, Germany
*e-mail: dmrzh@orc.ru
Abstract—Stationary states of molecular negative ions (anions) near the surface of a solid are
investigated. The lone electron is assumed to interact with a diatomic molecule and the surface of
the solid. The energies of electron levels are determined by solving the 2D Schrödinger equation. It
is shown that its stable solutions exist at distances from the surface greater than some critical
distance, otherwise the electron is detached from the anion. In the case of attraction between the
electron and the solid, the interaction potential between the anion and the solid appears to have the
Lennard–Jones form and the ion is separated from the surface by some equilibrium distance.
2
ON PLASMA COUPLING AND TURBULENCE EFFECTS
AT DENSE PLASMA STOPPING
Yu. K. Kurilenkov1 and G. Maynard2
1
Institute for High Temperatures of Russian Academy of Sciences, 13/19 Izhorskaya Str., 125412 Moscow,
Russia (ykur@online.ru )
2
Laboratoire de Physique des Gaz et des Plasmas, UMR-8578, Bât. 210, Université Paris XI, F-91405 Orsay,
France
The problem of stopping power (SP) for projectile ions is addressed and analyzed in terms of
dielectric function and dynamic collision frequency for moderately dense and strongly coupled
plasma (SCP). We concern the role of few aspects for calculation of stopping power for correlated
ensembles of particles and oscillators, in particular:
A) Consequent definition and calculation of SCP dynamic collision frequency, (k,);
B) Effects of poorly defined (group) collective modes domain, r0  k-1  a, appearing for nonDebye plasmas (r0  v Te /pe, a =(3/4 ni )1/3, k – wave number);
C) Transition from positive to negative dispersion  /k  0 (specifically low group velocity of
modes) at strong coupling (  1);
D) Excitation of collective modes up to suprathermal level ( therm) at dense plasmas as a
target ( = <E2>/8nT, E – the strength of plasma oscillations fields)).
Quasilinear stopping of dense suprathermal (nonlinear) plasma targets under different level of
induced plasma turbulence is calculated. The force of suprathermal plasma oscillations on the
beam ions is mostly in the nature of increased frictional drag. The results obtained show the
possibility of essential increasing of low velocity anomalous (“turbulent”) stopping in comparison
with losses at equilibrium dense plasma targets (partially, in analogy with the anomalously low
dense plasma conductivity and anomalous optical properties). The critical target plasma
parameters, energy loss functions at different approximations, synergism (or combination) of
different factors to influence the stopping as well as connection between stopping phenomena, and
SCP optical and transport properties are discussed. Some of the experimental conditions to create
specific turbulent targets (laser produced plasmas, dense pinched plasmas, isochoric heating of
solid density matter, etc.) as well as related molecular dynamics simulations data are analyzed.
#
Short paper and references related are also in the Proceedings of XXX European. Conference on Plasma
Physics and Controlled .Fusion, St-Petersburg, July 2003, http://eps2003.ioffe.ru/
3
REAL PROPERTIES OF FORCED TRANSPORT AND HEATING DYNAMICS OF
ELECTRONS IN BOLTZMANN GAS OF ATOMS
I.A. Boriev
Institute for Energy Problems of Chemical Physics (Branch) RAS
Using concepts of statistical physics and kinetics a logical consistent approach to description of
transport and heating dynamics for ensemble of electrons under the force of electric field in
disordered medium of elastically scattering atoms is developed [1]. The approach is based on
application of quantitative mutual relation between two elastic loss processes for electron (its
energy and transport impulse) by means of number of total elastic collisions required for relaxation
of that impulse and provides relation of time reversible equations of dynamics with irreversible
equations of kinetics what is necessary for study of open dissipative system.
It’s established from analysis of existent experimental data and easy confirmed by a priory
arguments based on properties of elastic scattering that for thermal electrons the number of such
collisions is equal to ~16, but for heavily forced transport heated (102-103 times) electrons this
number diminishes till ~4 [1,2]. As shown this unavoidable heating of electrons due to their forced
transport in such medium is accomplished by significant axially symmetric stretching of initially
isotropic electron velocity space along transport direction, what causes such reduction of collision
number. At stationary transport in strong field this phenomenon leads to ~3 times exceeding of
mean electron velocity in transport direction over that of in opposite one, signifying that mean
energy of such electrons differs (each other) ~9 times. It’s found that effective mass of electron
(with respect to its forced transport) depends on stretching extend of electron velocity space and is
several orders higher than the mass of free electron, being only 4-16 times ( the number of required
total elastic collisions) less than the mass of scattering atom.
The results obtained show that conventional assumptions about entire loss of electron transport
impulse in each one total elastic collision and about practical isotropy of velocity space of forced
transport heated electrons in boltzmann gas of atoms are both erroneous.
The established fundamental phenomenon of stretching of electron velocity space under the action
of external directing force, which undoubtedly is important for adequate description of collision
ionization in electric discharge plasma, is directly confirmed by existent experimental data for field
dependence of electron drift velocity in liquid rare gases. The account of this phenomenon allows to
give at first time clear qualitative and quantitative explanations both of peculiar (with two breaks)
behavior of this dependence for logarithmic coordinates (as display of two bifurcations of quasistationary states of electron velocity space) and of long time known effects of saturation of electron
drift velocity in these media at strong fields and of its multiple increase at small addition of
molecular impurity [1-3].
1. Boriev I.A. “Explanation of saturation effect of excess electron drift velocity under strong
electric field in condensed rare gases” (in Russian) // Khim.Fiz., 2003, V. 22, P. 80.
2. Boriev I.A. “About reasons of increase of quasi-free electron drift velocity in liquid rare gases at
small addition of molecular impurities” (in Russian) // Khim.Fiz., 2003, V. 22, P. 103.
3. Boriev I.A. “New features of forced transport and heating dynamics of quasi-free electrons
under electric field in dielectric medium” 30th EPS Conference on Controlled Fusion and
Plasma Phys., St. Petersburg, 7-11 July 2003 ECA Vol. 27A, P-2.185
(http://eps2003.ioffe.ru/PDFS/P2_185.PDF).
4
ENSEMBLES OF METASTABLE CLUSTERS COMPOSED OF ELEMENTS
WHICH DO NOT FORM THE CONDENSED MATTER
IN NORMAL CONDITIONS
V.F.Elesin, N.N.Degtyarenko, N.V.Matveev, L.A.Openov, A.I.Podlivaev
Moscow Engineering Physics Institute (State University)
The purpose of this work was to study theoretically a possibility of formation of the nitrogen
and helium clusters and their ensembles, as well as an accumulation of high energy in the cluster
structures. The existence of such metastable systems is predicted. It is shown that they are capable
to accumulate the energy up to (2  10) eV/atom that greatly exceeds the energy of the familiar
chemical materials. The structure and energetics of the clusters are determined. The cluster stability
and the processes of the energy release are studied. It is shown that up to 100% of the accumulated
energy is released upon the decay of nitrogen and helium systems. Contrary to the combustion
processes, the energy release is due to the fission of clusters and their ensembles into isolated
molecules and/or atoms, suggesting the practical advantages. So, the cluster structures are
promising candidates for the energy accumulation.
5
FOUR PHASES OF DEVELOPMENT OF AN ELECTRODELESS DISCHARGE
OF UNIPOLAR BREAKDOWN OF GAS (UBG) AND NECESSITY OF THE NEW WAY
OF LOOKING TO AN EXPLANATION ON A NATURE OF THE DISCHARGES
A.I. Gerasimov, I.V.Gerasimov, A.K.Suhov, M.N.Pyrshev, A.N.Selyankin
Kostroma State Univ., Kostroma, Russia.
e-mails: ellips@kmtn.ru; giv@ksu.kostroma.net
The phenomenology of the discharge of unipolar breakdown of gas (UBG) [1-3] puts many
questions having the direct relation not only to mechanisms of discharges processes, but also
touching the basic situation of the classical theory of electricity. The discharge tube of discharge
UBG has only one covering - electrode (CE), which is placed outside of one end of the long (  5 m)
tube; length of CE, l CE  0,5 m . Parameters of discharge UBG are: frequency of the unipolar (one
sign) pulses potential on CE, f i  40  1000 Hz ; amplitude of potential pulses,  i = 2.0  7.0 kV ;
duration of the pulse of  i , t i  2  10 s ; radius of the tube, rt  (3  30) mm ; pressure of gas,
p  (3  103  30) Torr .
In experiments with UBG four phases of development of the discharge are observed. The
first phase – dark, not observable (inductions phase), when at presence of pulse potential on coat electrode (CE) some time (about 5 minutes [1, 2]) the discharge - the luminescence of gas - is
absent. The second phase – an appearance of area of a luminescence in volume of gas directly under
a surface CE. The third phase - an appearance on some distance from CE of free volumetric charges
(FVChs) of a negative sign (at any polarity of high-voltage pulses on CE). The fourth phase longitudinal movement of FVChs inside volume of tube and occurrence of a luminescence of gas on
length of the discharge pillar.
The use of cylindrical CE has allowed to establish the proportional dependence of the initial
size of FVChs from parameters (from each) excitation of the discharge: from energy of an electrical
pulse on CE, -  PS  ii  t i  je SCE ,  ti  q    ,   , from pressure of gas p , from the sizes of the
surface CE, SCE , and duration ti of sign FVChs (as a single whole) is ionize, excite and polarize the
molecules of a vapor phase of the tested substance [3] or air [2] and is organize around FVChs the
luminous shells from these molecules.
The existence of several sequential phases development of discharge UBG, their property
has allowed use CE of cylindrical geometry. Thus the experiments installed dependence of
parameters describing each from 4 phases of discharge, from a gas pressure p , amplitudes  И and
duration tИ of an impulse potential, from geometry CE (plane CE on end walls of a tube or
cylindrical CE on its surface), from it of square S ПЭ and length l ПЭ : S ПЭ  2RT  l ПЭ , RT external radius of a tube).
The whole of properties distinguishing of the discharge UBG from known types of
discharges requires of the new way of looking to an explanation of a nature not only of this
discharge, but also phenomenon of electrical discharges as a whole, from diverse positions which
one should fundamentally of differ from known mechanisms of development of discharges .
References
[1] I.V. Gerasimov, Plasma Physics (Russia), 14 (1988), 1214-1221.
[2] I.V. Gerasimov. Journal of Technical Physics (Russia), 65 (1994), 30-37.
[3].Gerasimov A.I., Gerasimov I.V. Proc. XXV Int. Symposium on Plasma Chemistry,
Orleans. France. 2001, VIII, pp. 3303-3309.
6