München 2019 – wissenschaftliches Programm

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P: Fachverband Plasmaphysik

P 11: Atmospheric Pressure Plasmas III

P 11.1: Hauptvortrag

Dienstag, 19. März 2019, 14:00–14:30, HS 21

Electrical and optical characterisation of pulsed, single-filament dielectric barrier discharges on a water surface — •Hans Höft, Manfred Kettlitz, and Ronny Brandenburg — Leibniz-Institut für Plasmaforschung und Technologie e.V. (INP Greifswald), Felix-Hausdorff-Straße 2, 17489 Greifswald

A dielectric barrier discharge (DBD) on purified water was investigated by means of synchronised, fast electrical and optical diagnostics. For that purpose, a single, alumina-covered electrode with 2 mm radius was placed 1.5 mm above a standing liquid surface (purified water) and a grounded tungsten electrode underwater. The gas gap was constantly flushed with 0.1  vol% O₂ in N₂ at atmospheric pressure. The applied high-voltage (HV) pulse with ≈ 15 ns rise time was supplied by a fast Behlke switch using symmetrical, unipolar positive and negative amplitudes of 15 kV at 2 kHz repetition frequency. The diagnostics consisted of fast voltage and current probes and a gated iCCD camera to record the discharge structure occurring during the rising and falling slopes of the HV pulse. The current was measured at the grounded and the HV side. A single discharge event occurs at rising and falling slopes of the HV pulse. Due to character of DBDs the discharge at the slope, which turns to zero, is induced by surface charges on the dielectric surfaces. Depending on the polarity of the HV pulse, the surface charges are either positive (negative HV pulse) or negative (positive HV pulse). Consequently, distinct discharge morphologies were observed and correlated to the discharge current and the transferred charge per discharge event.