Aachen PK 2003 – wissenschaftliches Programm

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P: Plasmaphysik

P 17: Poster III

P 17.1: Poster

Donnerstag, 20. März 2003, 17:30–19:15, Foyer

Self-Consistent Description of the Anode Region of DC Glow Discharges — •Stefan Arndt, Florian Sigeneger, and Rolf Winkler — Institut für Niedertemperatur-Plasmaphysik, Greifswald, Germany

The anode region, i.e. the range from the positive column up to the anode surface of a dc glow discharge at low pressure and current is studied by a stationary and axially inhomogeneous hybrid method. Within the scope of this self-consistent method, the strict solution of the space-dependent kinetic equation of the electrons is iteratively coupled with those of the stationary hydrodynamic equations of the charge carriers and excited atoms as well as of the Poisson equation describing the space-charge potential. A comprehensive analysis of the plasma in the anode region is given. The plasma properties are mainly determined by the absorption of electrons at the anode and by the formation of space charges in front of it. Detailed results, particularly the axial profiles of the electric potential and field, the electron velocity distribution function and the related macroscopic quantities, the densities of the charge carriers and excited atoms, and the rates of electron-atom and atom-atom collisions, are presented for neon discharges at pressures at around one Torr. Experimentally known properties of the plasma in the anode region, such as the occurrence of an anode fall, the formation of plateau-like areas of the potential profile in front of the anode, the anode dark space, and the anode glow, have been confirmed by the model.