Formation of large-volume high-pressure plasma in triode-configuration discharge devices

A "plane cathode micro-hollow anode discharge (PCHAD)" is studied in comparison with micro-hollow cathode discharge (MHCD). A new triode-configuration discharge device is also designed for large-volume, high-pressure glow discharges plasma without glow-to-arc transitions, as well as with an anode metal needle, and a cathode of PCHAD. It has a "needle-hole" sustained glow discharge. Its discharge circuit employs only one power supply circuit with a variable resistor. The discharge experiments have been carried out in the air. The electrical properties and the photo-images in PCHAD, multi-PCHAD and "needle-hole" sustained discharge have been investigated. The electrical and the optical measurements show that this triode-configuration discharge device can operate stably at high-pressure, in parallel without individual ballasting resistance. And the electron density of the plasma is estimated to be up to 10(12) cm(-3). Compared with the two-supply circuit system, this electrode configuration is very simple with lower cost in generating large-volume plasma at high pressures.