Bochum 2015 – wissenschaftliches Programm

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P: Fachverband Plasmaphysik

P 6: Poster Session - Diagnostics

P 6.5: Poster

Montag, 2. März 2015, 16:30–18:30, Foyer Audimax

Imaging of Sparks and Streamers in Water — •Simon Hübner and Achim von Keudell — Application Oriented Plasma Physics, Ruhr-Universitaet Bochum, Germany

Plasmas in contact with or in liquids are interesting for treatment of water or material science because of the very high concentration of radical species and the strong quenching rates. In this work a preliminary plasma setup in liquid is presented, based on a pin-pin geometry. High voltage pulses with rise time of up to 40kV/100ns created by a thyristor switch provide streamers or sparks depending on the distance of the electrodes. The temporal and spatial evolution of the discharge in the liquid phase is studied by optical emission, shadographic and Schlieren imaging. With the visualization techniques the shock front and streamer propagation velocities can be obtained. Under the conditions of this study the streamer evolves probably within nano-scaled pores or polarized zones, since light emission starts well before bubble formation. Moreover, the long term evolution of the filament evolving into a gas bubble can be captured. Potential applications are discussed.