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P: Fachverband Plasmaphysik

P 15: Poster: Diagnostik

P 15.8: Poster

Wednesday, April 1, 2009, 17:30–19:30, Foyer des IfP

Striations in BD microdischarges at atmospheric pressure in argon with admixtures — •Helge Grosch, Tomas Hoder, Jan Schäfer, Christian Wilke, and Ronny Brandenburg — INP Greifswald e.V.; F.-Hausdorff-Str. 2; 17489 Greifswald

Barrier discharges (BD) have a broad spectrum of applications. Especially for surface treatment argon is a suitable carrier gas, but usually it is impurified by air when working in an open environment. There is little known about the development of BDs in such gas mixtures.

Microdischarges in a one-sided BD at atmospheric pressure between two semispherical electrodes are investigated. The gap between the electrodes is set around 1 mm and more. The carrier gas is argon with defined admixtures of nitrogen or synthetic air. The current and voltage are measured with an oscilloscope. A far field microscope, with magnification of about 300, is combined with an iCCD camera as the imaging method.

From our knowledge, for the first time striations similar as in positive column in low-pressure DC glow discharges has been observed in a BD microdischarge. Striations are observed in the discharge gap as well as on the dielectric electrode, if the metal electrode is the cathode. Recent investigations intend to stabilize the microdischarges in order to investigate them systematically.