Aachen PK 2003 – scientific programme

Parts | Days | Selection | Search | Downloads | Help

P: Plasmaphysik

P 14: Basic Plasma Physics, Theory

P 14.3: Talk

Thursday, March 20, 2003, 12:10–12:30, FO2

Comparative kinetic analysis of the electron behaviour in the anode region of glow discharge plasmas — •Detlef Loffhagen, Florian Sigeneger, and Rolf Winkler — Institut für Niedertemperatur-Plasmaphysik, 17489 Greifswald, Germany

Boltzmann equation and Monte Carlo studies of the axial behaviour of the electron component in the column-anode region of low-pressure dc glow discharges have been performed. The elaborate method for solving the spatially inhomogeneous Boltzmann equation of the electrons is based upon a multiterm treatment of the velocity distribution function expansion in Legendre polynomials and makes, in particular, use of generalized boundary conditions for the partially absorbing anode. The influence of the anode fall and of the electron absorption at the anode on microscopic and macroscopic properties of the electrons have been studied in various approximation orders of the multiterm treatment. The analysis reveals that the simpler two-term treatment of the kinetic equation of the electrons can lead to considerable discrepancies from the convergent behaviour. The latter is generally obtained by a multiterm approximation including six to eight terms. The differences between the two-term and convergent results become the more distinct, the stronger and steeper the increase of the electric field in the anode fall region takes place, but depend only little on the degree of electron absorption at the anode. The impact of the anode fall leads to a pronounced nonlocal behaviour of the electrons close to the anode. The results obtained by the convergent approximation are impressively confirmed by the excellent coincidence with corresponding results obtained by Monte Carlo simulations.