High pressure microhollow cathode discharges in air
- Old Dominion Univ., Norfolk, VA (United States). Physical Electronics Research Inst.
Research on high pressure, large volume glow discharges in air is motivated by applications such as reflectors and absorbers for electromagnetic radiation, plasma processing, and the remediation of gaseous pollution. In order to prevent glow-to-arc transitions, which in high-pressure glow discharges start in the cathode region, it is proposed to use a plasma cathode consisting of an array of microhollow cathode discharges. To explore the conditions for stable operation of single 100 {micro}m microhollow cathode discharges in flowing air, the current-voltage characteristics, and the visual appearance of a 100 {micro}m microhollow cathode discharge were studied. The results show that the threshold current for the transition from a glow into a filamentary discharge varies inversely with pressure. At pressures of 400 Torr the current in the 100 {micro}m hollow cathode discharge must not exceed 0.5 mA in order for the discharge to be stable. The type of instability, which causes the transition from dc to fluctuating currents, is not known at this time, but the observed dependence of the threshold current from the gas pressure points to a thermal instability. Assuming that the White-Allis scaling law still holds for air discharges at pressures close to atmospheric, it is expected that reducing the cathode hole diameter to 50 {micro}m will allow us to operate microhollow cathode discharges at atmospheric air with currents of up to 0.25 mA. Experimental studies on the effect of the cathode dimensions and cathode material are underway and results will be discussed at the conference.
- Sponsoring Organization:
- Department of the Air Force, Washington, DC (United States); USDOE, Washington, DC (United States)
- OSTI ID:
- 346886
- Report Number(s):
- CONF-980601-; TRN: IM9920%%103
- Resource Relation:
- Conference: 25. international conference on plasma science, Raleigh, NC (United States), 1-4 Jun 1998; Other Information: PBD: 1998; Related Information: Is Part Of IEEE conference record -- Abstracts. 1998 IEEE international conference on plasma science; PB: 343 p.
- Country of Publication:
- United States
- Language:
- English
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