Hannover 2010 – wissenschaftliches Programm

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P: Fachverband Plasmaphysik

P 19: Poster: Low Temperature Plasmas II

P 19.1: Poster

Donnerstag, 11. März 2010, 16:00–18:00, Lichthof

Theoretical studies of pulsed xenon glow discharges at medium pressure — •Mykhaylo Gnybida, Dirk Uhrlandt, and Detlef Loffhagen — INP Greifswald, Felix-Hausdorff-Str. 2, 17489 Greifswald, Germany

Pulsed medium-pressure glow discharges in xenon have been investigated by means of a time-dependent, spatially one-dimensional fluid model. The model consists of the coupled solution of the balance equations for the charge carrier and neutral species densities, the mean electron energy and the gas temperature in the plasma. The space-charge potential of the radially inhomogeneous plasma and the axial electric field are determined by solving the Poisson equation and a current balance, respectively. The electron transport and rate coefficients are adapted as functions of the mean electron energy, gas temperature and ionization degree. They were obtained from the solution of the steady-state, spatially homogeneous electron Boltzmann equation including electron-electron collisions. The analysis has been performed for xenon plasmas in a discharge tube with an inner diameter of 6.5 mm at currents between 60 and 150 mA and pressures from 10 to 50 Torr. Main features of the spatiotemporal evolution of the pulsed xenon discharges are discussed. The comparison of the model predictions with experimental results generally shows good agreement. The model results reproduce the significant increase of the low-lying (metastable and resonance) atomic state densities in the early afterglow phase of the pulse, which has also been observed in the experiments.

The work was supported by the DFG within SFB-TR 24.