Dust particle radial confinement in a dc glow discharge

Abstract

A self-consistent nonlocal model of the positive column of a dc glow discharge with dust particles is presented. Radial distributions of plasma parameters and the dust component in an axially homogeneous glow discharge are considered. The model is based on the solution of a nonlocal Boltzmann equation for the electron energy distribution function, drift-diffusion equations for ions, and the Poisson equation for a self-consistent electric field. The radial distribution of dust particle density in a dust cloud was fixed as a given steplike function or was chosen according to an equilibrium Boltzmann distribution. The balance of electron and ion production in argon ionization by an electron impact and their losses on the dust particle surface and on the discharge tube walls is taken into account. The interrelation of discharge plasma and the dust cloud is studied in a self-consistent way, and the radial distributions of the discharge plasma and dust particle parameters are obtained. It is shown that the influence of the dust cloud on the discharge plasma has a nonlocal behavior, e.g., density and charge distributions in the dust cloud substantially depend on the plasma parameters outside the dust cloud. As a result of a self-consistent evolution of plasma parameters to equilibrium steady-state conditions, ionization and recombination rates become equal to each other, electron and ion radial fluxes become equal to zero, and the radial component of electric field is expelled from the dust cloud.

Non‐local electron kinetics around the cloud of dust particles

“…To describe the electron component of the discharge plasma, a non-stationary non-local Boltzmann equation for isotropic part of EEDF f 0 (U, r, t) was used in the form [6,7] :…”

“…In the first case, dust distribution was a given step-like function of a radial coordinate (as in Sukhinin et al [5,6] ) and do not change in time: In this paper, the radial distribution of the dust particles in the cloud N d (r, t) was used in calculations in two forms.…”

“…[1][2][3][4][5][6][7][8][9][10][11][12][13] It was understood that electron and ion losses on dust particle surface should be compensated for in ionizing collisions, and an averaged electric field should increase in the region containing dust particles. The influence of dust particles on gas discharge plasma is negligible only for low dust particles concentration and charge.…”

“…[6][7][8] For example, dust particle charging is provided by the electron and ion fluxes into the cloud from the surrounding plasma. [6][7][8] For example, dust particle charging is provided by the electron and ion fluxes into the cloud from the surrounding plasma.…”

Dust in Plasma I. Particle Size and Ion‐Neutral Collision Effects

“…Eq. Analytical [10][11][12][13] and numerical [14][15][16][17][18][19][20][21][22][23] models developed for such goal have been limited to some approximations: prescribed electron/ion distribution function, linear systems, fluid or hybrid approaches, steady-state analyses, non-realistic electron to ion mass ratio, and it still lacks a complete and comprehensive knowledge of the problem. However, this simple approach to derive eq.…”