Mainz 1997 – wissenschaftliches Programm

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P: Plasmaphysik

P 13: Postersitzung I

P 13.63: Poster

Dienstag, 4. März 1997, 16:00–18:00, Foyer

Calculation of electron kinetic properties in the cathode fall region of dc glow discharges — •G. Petrov and R. Winkler — Institut für Niedertemperatur-Plasmaphysik, Robert-Blum-Str. 8–10, D-17489 Greifswald

The cathode region of low pressure glow discharges is of particular interest for many applications as well as for a deeper understanding of the non-equilibrium behaviour in this and similar plasma regions. The efforts to model the cathode region have been limited by the lack of hydrodynamic equilibrium and the presence of strong electric field gradients near the cathode. Most of the approaches, based on particle simulation techniques (Monte Carlo and convective scheme methods) of the electrons or the direct solution of the electron Boltzmann equation, are either very time consuming and of limited accuracy or too simplified. Accurate solutions of the electron Boltzmann equation in the cathode region can be obtained when using a higher order expansion of the electron velocity distribution function (EVDF) in Legendre polynomials [1]. Based on such an approach, an accurate description of the lowest two expansion components of the EVDF, which determine the energy distribution and the macroscopic quantities of the electrons, has been achieved and their convergence behaviour with increasing expansion order has been investigated. This method proves to be applicable and efficient even in such extreme field alterations as occurring in the cathode-fall region.

[1] G.Petrov and R.Winkler, J. Phys. D: Appl. Phys. 29 (1996) in print