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P: Fachverband Plasmaphysik
P 24: Low Temperature Plasmas II
P 24.6: Vortrag
Donnerstag, 3. März 2016, 16:10–16:25, b305
Spatio-temporal characterisation of multiple diffuse and single filamentary breakdowns in a plane-parallel barrier discharge configuration — •Robert Tschiersch1, Sebastian Nemschokmichal1, Marc Bogaczyk2, and Jürgen Meichsner1 — 1Institute of Physics, University of Greifswald, Felix-Hausdorff-Str. 6, 17489 Greifswald, Germany — 2Leibniz Institute for Plasma Science and Technology, Felix-Hausdorff-Str. 2, 17489 Greifswald, Germany
Helium-nitrogen barrier discharges (BDs) were operated at gas pressures from 100 mbar up to 1 bar inside an interelectrode gap of 3 mm using a concentric, plane-parallel discharge cell configuration. The latter enables the formation of multiple diffuse breakdowns per half cycle of the sinusoidal feeding voltage, as well as laterally patterned BDs and single filamentary BDs driven by a square wave voltage. These discharge modes were comprehensively studied by electrical measurements, optical emission spectroscopy and surface charge diagnostics. Regarding the multiple diffuse breakdowns, the spatio-temporally resolved optical emission identifies the first breakdown as the glow mode, the last breakdown as the Townsend mode, and the ones in between as a hybrid of both modes. As shown by the surface charge measurements, the consecutive breakdowns ignite alternately at laterally inner and outer regions of the electrode. Regarding the breakdown mechanism of patterned BDs as well as single filamentary BDs, the investigations reveal characteristics which declare this discharge type as an intermediate between the glow mode and the microdischarge.