Greifswald 2009 – scientific programme

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P: Fachverband Plasmaphysik

P 9: Poster: Niedertemperaturplasmen

P 9.25: Poster

Tuesday, March 31, 2009, 17:30–19:30, Foyer des IfP

Self-pulsing of a micro hollow cathode discharge — •Beilei Du, Sebastian Mohr, Dirk Luggenhölscher, and Uwe Czarnetzki — Institute for Plasma and Atomic Physics, Ruhr-University Bochum, 44780 Bochum, Germany

Micro hollow cathode discharges (MHCD) consist of two electrodes separated by a thin dielectric (100 µm). The discharge develops in a hole penetrating all three foils (200 µm diameter). When powered by a DC voltage of several 100 V, the discharge shows self-pulsing operation. The pulse frequency can range from several kHz up to about 1 MHz and the pulse width can be as short as several 10 ns. The self-pulsing and the discharge ignition is investigated in argon at pressures ranging from several 1000 Pa to atmospheric pressures. Voltage and current measurements as well as optical emission measurements by an ICCD camera equipped with a microscope lens are performed. The pulse frequency is related to the capacitance of the discharge setup. Due to the smallness of all components stray capacitances are actually quite important. The circuit is critically analyzed and consequences for interpretation of the measured current waveforms are discussed. The voltage-current characteristic shows a transition from abnormal mode to spark mode as in a DC glow discharge.