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P: Plasmaphysik

P 24: Entladungen (Poster)

P 24.20: Poster

Tuesday, March 16, 1999, 16:30–19:00, PY

Parallel Operation of Microhollow Cathode Discharges — •Robert H. Stark, Wenhui Shi, and Karl H. Schoenbach — Physical Electronics Research Institute, Old Dominion University, Norfolk, VA 23529, USA

The dc current-voltage characteristics of microhollow cathode discharges has, in certain ranges of the discharge current, a positive slope. In these current ranges it should be possible to operate multiple discharges in parallel without individual ballast. Such arrays could be used as flat panel excimer lamps or large area plasma cathodes. In order to verify this hypothesis we have studied the parallel operation of two microhollow cathode discharges of 100 micrometer hole diameter in argon at pressures from 100 torr to 800 torr. Stable dc operation of the two discharges, without individual ballast, was obtained if the voltage-current characteristics of the individual discharges had a positive slope greater than 10 V/mA over a voltage range of more than 5 % of the sustaining voltage. In order to obtain parallel operation over the entire current range of the microhollow cathode discharges, which includes regions of negative differential conductivity, we have replaced the metal anode by a semi-insulating semiconductor, which serves as distributed resistive ballast. With this method, we were able to ignite and sustain an array of 16 dc microhollow cathode discharges over a wide range of pressure and discharge current.

This work was funded by the Department of Energy, Advanced Energy Division, and by the Air Force Office of Scientific Research (AFOSR) in cooperation with the DDR&E Air Plasma Ramparts MURI Program.