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P: Plasmaphysik
P 13: Entladungen III
P 13.3: Talk
Thursday, March 18, 1999, 14:45–15:00, ZO 2
Pulsed Operation of Microhollow Cathode Discharges in Atmospheric Air — •Uwe Ernst1, Robert H. Stark2, Karl H. Schoenbach2, Klaus Frank1, and Werner Hartmann3 — 1Department of Physics, University of Erlangen-Nuremberg, Germany — 2Physical Electronics Research Institute, Old Dominion University, Norfolk, VA 23529, USA — 3Siemens AG Erlangen, Germany
Reducing the diameter of the cathode opening to values on the order of 100 micrometer allowed us to operate stable dc hollow cathode glow discharges in air at atmospheric pressure. Discharge currents of up to 30 mA with forward voltages around 400 V have been realized. In order to generate arrays of microhollow cathode discharges without resistive ballast, the current voltage characteristic of the discharge needs to have a positive slope. Results of modeling show the required increase of the forward voltage with current at high current values. However, overheating of the electrodes prevents dc operation of parallel discharges in atmospheric air in this current range. In order to extend the range of operation into the high current mode, the discharge has been operated pulsed with pulse duration from 1 to 100 microsecond. First experimental results confirm the modeling results. The electrical characteristic and the optical appearance of the discharge plasma in pulsed microhollow cathode discharges and its applications will be discussed. This work was supported by the National Science Foundation (NSF), the Air Force Office of Scientific Research (AFOSR) and Siemens Germany.