CC BY
36Complex Systems of Charged Particles and their Interactions with Electromagnetic Radiation 2019
CHARACTERISTICS OF THE METAL IONS DRIFT IN HELIUM
S.A. Maiorov12, V.S. Kurbanismailov3, G.B. Ragimkhanov3, Z.R. Khalikova3
1Prokhorov General Physics Institute of the Russian Academy of Sciences, Moscow, Russia Joint Institute for High Temperature of the Russian Academy of Sciences, Moscow, Russia 3Dagestan State University, Makhachkala, Russia, e-mail: gb-r@mail.ru
In this paper, we analyzed the features of collisions of metallic ions (Fe, Li, Cu, W, Hg) with inert gas atoms, taking into account polarization and gas-kinetic interactions in the model of hard spheres. The results of Monte Carlo calculations of the characteristics of the drift of a metal ion (Fe, Li, Cu, W, Hg) in a constant and uniform electric field at 1<E /N <1000 Td in helium are presented.
The features of the ion velocity distribution are shown in Fig. 1, which for four different field strengths are constructed distribution functions of iron ions along the velocity projections along (a) and across (b) the field in helium for different values of the electric field strength. These four values of the field strengths characterize the weak field regimes (the deviation from the equilibrium distribution is small), the moderate one - the deviation from the equilibrium distribution is significant, and the strong one - the deviation from the equilibrium distribution is significant and differs from it qualitatively.
Analysis of the distribution functions shows that when ions drift, in typical conditions for a gasdischarge plasma, there is a significant heating of the ions not only in the longitudinal direction, but also in the transverse direction. And in the distribution of ions over the velocities, a large anisotropy was found both along and across the field direction, and the distribution in velocity and in velocity projections has significant differences from the corresponding Maxwellian distributions. The ion velocity distribution function during their drift in helium cannot be described by a Gaussian curve (shifted by the Maxwell distribution function). 0,4 r
0,3
■-R 0,2
0,1
0,0
«
M
11 I1 I I I I I I I I I I
E/N=10 Td
Fe+/He T=300K
E7N=50 Td
E7N=100 Td
E7N=300 T<
J
b
\
I
y
Fig.1a
0 10 20 30
velocity / termal velocity
0,4
0,3
0,2
0,1
0,0
Fe+/He T=300 K
E/N=10 Td
ir
K
E/N=50 Td
E/N=100 Td
y /
E/N=300 Td
y V
0-505
velocity / termal velocity
Fig.1b
It is shown that there is a large difference between the longitudinal and transverse temperatures. Therefore, diffusion flows along and across the field can vary greatly in magnitude. It should be noted that even with a sufficiently high reduced electric field strength, there is no formation of an ion flow in which the speed of thermal chaotic motion would be less than the speed of directional motion - the drift velocity. The data obtained in the work can have real practical application.
This work was supported by the RFBR grant No. 19-08-00611a.
