Electron kinetics in non-uniform glow discharge plasmas

Abstract

The various analytic approaches to the solution of the electron Boltzmann equation in non-uniform glow discharge plasmas in atomic gases are presented. For slow electrons with kinetic energy w<or= epsilon 1 ( epsilon 1 is the first excitation potential), for which the traditional two-term approximation for the distribution function is valid, the situation can be radically simplified in the non-local case, for which the energy relaxation length exceeds the characteristic scale. Numerous manifestations of non-locality in the positive column, the anode and the cathode regions of the direct current glow discharge, in striations, in capacitively and inductively coupled low-pressure radiofrequency discharges and so on are discussed. For fast electrons of w>> epsilon 1, the approximation of continuous energy losses can be used. The simplest approximation corresponds to the neglect of scattering. In this case, simple analytic expressions for the distribution of the fast electrons, for the multiplication factor and so on can be derived, and the structure of normal and abnormal cathode regions for plane and hollow cathodes can be analysed.