Bremen 2017 – wissenschaftliches Programm
P 23.5: Poster
Mittwoch, 15. März 2017, 16:30–18:30, HS Foyer
Single self-stabilized filament in plane-parallel barrier discharge configuration: existence regimes, breakdown mechanism, and memory effects — •Robert Tschiersch, Sebastian Nemschokmichal, and Jürgen Meichsner — Institute of Physics, University of Greifswald, Felix-Hausdorff-Str. 6, 17489 Greifswald
This contribution reports on a single filament which is self-stabilized in the plane-parallel barrier discharge configuration. The discharge is operated inside a gap of 3 mm shielded by glass plates on both electrodes, using helium-nitrogen mixtures and square-wave feeding voltage at a frequency of 2 kHz. The combined application of electrical measurements, ICCD camera imaging, optical emission spectroscopy, and surface charge diagnostics allowed to study the correlation between volume and surface processes during the discharge development. Priority is given to the formation conditions, breakdown mechanism, and underlying memory effects. Therefore, the existence regimes were investigated by systematic variation of the nitrogen admixture to helium, the total pressure, and the feeding voltage amplitude. In each case, the single self-stabilized discharge filament is obtained by significant reduction of the voltage amplitude after the discharge ignition in the multi-filament regime. Here, the outstanding importance of the surface-charge memory effect for the long-term stability is pointed out by the calculation of the spatio-temporally resolved gap voltage. The optical emission from the discharge reveals characteristics that are partially reminiscent of both the glow-like barrier discharge and the microdischarge regime.