Bochum 2015 – scientific programme

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P: Fachverband Plasmaphysik

P 25: Low Temperature Plasmas III

P 25.3: Talk

Thursday, March 5, 2015, 11:10–11:25, HZO 30

Characterization of Propagating Ionization Waves in Atmospheric Pressure Discharges — •Max Engelhardt, Nikita Bibinov, and Peter Awakowicz — Ruhr-Universität Bochum, Lehrstuhl für Allgemeine Elektrotechnik und Plasmatechnik, Universitätsstraße 150, 44801 Bochum

The phenomenon of propagating ionization waves at atmospheric pressure, which is often referred to as plasma bullets, is well described in literature. This field of research is especially interesting for biomedical applications, where simple discharge types are needed, that allow direct treatment of biological tissue. The device used is a dielectric barrier plasma jet, which is basically a quartz tube in which plasma is excited by application of high voltage (HV) pulses to an electrode wrapped around the outer wall of the tube. Out of the open end, a so-called effluent is ejected several centimeters beyond the tube. HV pulses are produced in a custom-made generator, which allows studies with independent tuning of relevant parameters. The discharge is characterized with different diagnostic methods, namely current-voltage characteristics and short-time photography. Short-time photography is performed with an intensified CCD camera which has a minimum exposure time of 200 ps. By using a delay generator between the pulse generator and the camera, pictures can be taken of the temporal evolution of plasma bullets. The results show considerably deviating discharge properties for different parameters. Variations are also noticeable in effluent properties, such as varying length and electric current through the discharge.