Aachen PK 2003 – scientific programme

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P: Plasmaphysik

P 15: Low Temperature Plasmas, Plasma Technology

P 15.5: Talk

Thursday, March 20, 2003, 16:50–17:10, FO1

Theoretical investigations of a low-pressure dc He-Xe discharge for lighting purpose — •Sergej Gortchakov, René Bussiahn, Hartmut Lange, and Dirk Uhrlandt — Institut für Niedertemperatur-Plasmaphysik, 17489 Greifswald, Germany

Low-pressure cylindrical glow discharges in mixtures of xenon with other rare gases can be applied in environmentally compatible sources of VUV radiation and visible light. The analysis of operation conditions and their optimization with respect to the radiation efficiency and output power can be performed by a self-consistent description of the positive column of such plasmas. A new comprehensive model of the dc column plasma in helium-xenon mixtures is presented. The model is based on a hybrid method which comprises a spatially resolved kinetic treatment of the plasma electrons, a detailed description of the balances of the charge carriers and of the excited states in xenon as well as a self-consistent determination of the axial heating field and the radial space-charge field. The model is confirmed by a detailed comparison with experimental results for the electric field and the densities of excited states, obtained by probe and diode laser absorption diagnostics. The evaluation includes a discussion of the applied collision-radiative model of xenon and of the choice of the electron collision cross sections. It has been found that a change of the cross sections for the excitation of ground and excited xenon atoms within their range of uncertainty has a considerable impact on the results.