Hannover 2010 – scientific programme

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P: Fachverband Plasmaphysik

P 18: Poster: Diagnostics

P 18.7: Poster

Thursday, March 11, 2010, 16:00–18:00, Lichthof

Electrical and emission spectroscopic investigation of a micro thin cathode discharge — •Beilei Du, Sebastian Mohr, Dirk Luggenhölscher, and Uwe Czarnetzki — Institute for Plasma and Atomic Physics, Ruhr-Universität Bochum, 44780 Bochum Germany

Micro hollow cathode discharges consist of two plan parallel electrodes separated by a thin dielectric (100 µm). A small hole with a diameter similar to the width of the dielectric penetrates this sandwich structure. If the cathode is made very thin, i.e. smaller than the hole diameter, the current density of the cathode edge can reach very high value that can lead to thermionic electron emission. We call this structure Micro Thin Cathode Discharge (MTCD). At atmospheric pressure the MTCD shows under DC-voltage a self-pulsing behavior due to a periodic arc transition. The current is temporally (a few 10 ns) supplied by the charge stored in the capacitance of the sandwich structure. High electron density in the range from 10¹⁶ cm⁻³ to 10¹⁷ cm⁻³ can be reached for a time of a few 100 ns. Current, voltage, plasma density, temperature and spatially resolved emission spectroscopy measurements are presented.