Study of the radial structure of the electron kinetics in the DC column plasma

Conference · Sun Dec 31 04:00:00 EST 1995

OSTI ID:212807

Uhrlandt, D; Winkler, R ^[1]

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1. Institut fuer Niedertemperatur-Plasmaphysik, Greifswald (Germany)

The stationary and axially homogeneous positive column of a glow discharge is a well studied example of a bounded plasma confined by a space charge potential. The potential decreases towards isolated walls in order to limit the electron current but drive the ion current to the walls. This confinement leads to significant spatial dependencies of the plasma kinetics which is far away from equilibrium with the local electric field. A strict description of the spatially dependent electron kinetics requires the solution of the relevant inhomogeneous kinetic equation for the electron velocity distribution function (EVDF) including the action of the electric space charge field. Using a two-term expansion in spherical harmonics, the EVDF contains, in addition to the isotropic distribution, a vectorial anisotropy. This paper deals with the study of the detailed radial structure of the electron kinetics in the positive column of a DC glow discharge in a cylindrical tube. The inhomogeneous kinetic equation is completed by appropriate boundary conditions. An efficient numerical approach was developed to solve the resulting elliptic boundary value problem and to calculate the isotropic and anisotropic components of the EVDF. As an example the positive column of a real neon glow discharge is investigated including the radial space charge potential. The radial dependence of the isotropic and anisotropic EVDF components as well as of the most important macroscopic quantities is presented. Furthermore, the spatially resolved electron energy balance is analysed to demonstrate the distinctly nonlocal properties of the electron kinetics.

• OSTI ID: 212807
• Report Number(s): CONF-950749--
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
BOLTZMANN EQUATION
BOUNDARY-VALUE PROBLEMS
DISTRIBUTION FUNCTIONS
ELECTRON DENSITY
ELECTRONS
GLOW DISCHARGES
SPACE CHARGE