Computational methods for the study of collision processes in glow discharge plasmas

Abstract

The influence of basic elementary processes in a simplified model of an Ar plasma on the electron distribution function has been studied by computer experiment. The main aim of simulation was to build the qualitative model of plasma based on a reduced set of scattering processes. Its ability to maintain a given, e.g. Maxwellian, distribution of electron energies was chosen as a criterion for correctness of the model. It was found that in the positive column of dc glow discharge, in inert gas plasma, the minimal set of electron interactions must consist of collisions: electron-neutral atom (elastic, excitation and ionisation), electron-electron and electronpositive ion. A combination of the Monte Carlo and molecular dynamics methods with some new algorithms for deterministic calculations (particle mesh Ewald method and Fast Multipole method) was adopted as a simulation technique. The Monte Carlo method was found to be much more effective than even the best deterministic algorithms. However, as the Monte Carlo method has a limited accuracy only, an attempt was made to improve it.