Hannover 2010 – scientific programme

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P: Fachverband Plasmaphysik

P 19: Poster: Low Temperature Plasmas II

P 19.2: Poster

Thursday, March 11, 2010, 16:00–18:00, Lichthof

On the hysteresis transition between diffuse and constricted modes of glow discharges in argon — •Mykhaylo Gnybida, Dirk Uhrlandt, and Detlef Loffhagen — INP Greifswald, Felix-Hausdorff-Str. 2, 17489 Greifswald, Germany

The transition of the diffuse glow discharge to a contracted state in argon plasmas has been studied by means of a time- and radial-dependent fluid model. The self-consistent model comprises the particle balance equations for electrons, atomic and molecular ions, three excited atomic and two excited molecular states, the balance equation of the mean electron energy and of the heavy particle temperature in the plasma, Poisson’s equation for the space-charge potential, and the external circuit equation determining the axial electric field and the discharge current. The transport and rate coefficients of the electrons are obtained from the solution of the 0D Boltzmann equation for the electron velocity distribution function. The investigations have been performed for plasmas in a discharge tube with a radius of 1 cm at pressures from 100 to 500 Torr. The results show the classical hysteresis effect: the transition from glow to constricted mode at increasing current and the opposite transition at decreasing current occur at different values of discharge parameters. The predicted voltage-current characteristics are compared with available experimental data. Good agreement is found in general.

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