Micro hollow cathode discharges
- Old Dominion Univ., Norfolk, VA (United States). Physical Electronics Research Inst.
Hollow cathode discharges are glow discharges with the cathode fall and negative glow confined in a cavity in the cathode. For the discharge to develop, the cathode hole dimensions must be on the order of the mean free path. By reducing the cathode hole dimensions it is therefore possible to increase the pressure. Stable hollow cathode discharges in air have been observed at almost one atmosphere when the cathode diameter was reduced to 20 micrometers. In order to study the electrical parameters of a micro hollow cathode discharge, a set of experiments has been performed in argon at pressures in the torr range and a cathode hole diameter of 0.7 mm in molybdenum. The current-voltage characteristics and the appearance of the discharge plasma showed two distinct regions. At lower voltage or pressure the current varies linearly with voltage and the hollow cathode plasma is concentrated around the axis of the cathode hole (low glow mode). At higher values of voltage or pressure the current increases nonlinearly, up to a point where a transition into a low voltage hollow cathode arc was observed, and the plasma column expands and fills almost the entire cathode hole (high glow mode). Spectral measurements showed that the transition from the low glow mode into the high glow mode is related to an increased density of electrode vapor in the hollow cathode discharge. Up to the breakdown into a hollow cathode arc, the current voltage characteristic of the discharge has a positive slope. In this range, hollow cathode discharges can be operated in parallel without a ballast resistor.
- OSTI ID:
- 163170
- Report Number(s):
- CONF-950612-; ISBN 0-7803-2669-5; TRN: IM9604%%274
- Resource Relation:
- Conference: 22. international conference on plasma science, Madison, WI (United States), 5-8 Jun 1995; Other Information: PBD: 1995; Related Information: Is Part Of IEEE conference record -- abstracts: 1995 IEEE international conference on plasma science; PB: 312 p.
- Country of Publication:
- United States
- Language:
- English
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