Impact of Electron–Electron Collisions on the Spatial Electron Relaxation in Non-Isothermal Plasmas

Abstract

The impact of electron-electron collisions on the spatial relaxation of electrons in the column-anode plasma of a glow discharge, acted upon by a spaceindependent electric field and initiated by a constant influx at the cathode side of the plasma, is investigated in inert gas plasmas. The investigations are based on a new method for numerically solving the one-dimensional inhomogeneous Boltzmann equation of the electrons including electron-electron interaction in weakly ionized, collision-dominated plasmas. A detailed analysis of the spatial behaviour of the velocity distribution function and relevant macroscopic properties of the electrons is given for various degrees of ionization and electric field strengths. A significant impact of the electron-electron collisions on the relaxation structure and the resultant relaxation length already at relatively low ionization degrees has been found for low to medium electric fields.

Striated microdischarges in an asymmetric barrier discharge in argon at atmospheric pressure

“…(3) for the spatial region from the metal electrode at z = 0 and the dielectric anode at z = 0.15 cm, the axially inhomogeneous Boltzmann equation of the electrons including electron-electron collisions has been solved numerically for argon gas at atmospheric pressure and a gas temperature of 300 K using the solution method described in [56]. Therefore, the Gaussian-like function…”

First principles calculation of the effect of Coulomb collisions in partially ionized gases

“…As a further consequence of this transport coefficients also change remarkably with η. 11 The changes of the shape of the VDF are illustrated in Fig. 3.…”

“…13 Inclusion of Coulomb collisions in either the BE, or the MC approaches represents a significant challange, due to the long-range nature of the Coulomb potential. One possible simplification is to treat the multiple electronelectron interactions as a succession of discrete, binary collisions; this approximation has often been adopted in Boltzmann equation analysis, 11,[14][15][16] as well in Monte Carlo simulations. 17,18 Different methods for a more efficient description of Coulomb collisions have also been proposed.…”

Electron Kinetics and Self‐Consistent Description of Inhomogeneous and Nonstationary Plasmas

“…The electron kinetics of quite different problems could successfully be analysed extending from basic problems in model plasmas up to problems in real discharge arrangements. In particular, (i) the electron kinetics in the anode region of dc glow discharges [21], (ii) the behaviour of the electron gas in the spatial decay to the remote plasma region [22,23], (iii) the spatial kinetics of trapped electrons effected by the occurrence of a potential energy valley in the plasma [23], (iv) the response of the electron gas to the spatial field transition from accelerating to retarding electric fields occurring in grid-controlled arrangements [24], (v) the spatiotemporal transition and propagation processes of the electron gas in the column-anode region of a glow discharge [25], and (vi) the additional impact of electron-electron collisions on the spatial [26,27] and spatiotemporal [28] relaxation of plasma electrons have been investigated.…”

“…for the isotropic distribution f 0 (z, U, t) can be deduced from the Boltzmann equation [26,35], where Y (z, t) depends weakly on the density n e (z, t) and mean energy u m (z, t) of the electrons according to [36] Y (z, t) = 1 4π…”