Microhollow cathode discharges as plasma cathodes for atmospheric pressure glow discharges in air

Abstract

Summary form only given. One of the main obstacles for do operation of high-pressure glow discharges is the glow-to-arc transition, an instability that originates in the high field region of the discharge: the cathode fall. Reduction or even elimination of the cathode fall is possible by using a plasma cathode. A microhollow cathode discharge (MHCD) has been used as plasma cathode for a glow discharge in air, sustained between the hollow anode of the MHCD and a third electrode which was positively biased with respect to the MHCD anode. With this method we were able to obtain stable DC operation in air up to atmospheric pressure without reaching the threshold for glow-to-are transition. Current and voltage characteristics, axial electric field distribution and the visual appearance of this glow discharge and the MHCD were studied in air at atmospheric pressure. In order to obtain the stable air discharge the current in the MHCD needs to exceed a threshold value. Typical threshold currents for a 100 /spl mu/m diameter hollow cathode are 5-10 mA. Above the threshold, the current in the glow discharge is identical with the MHCD current and can be controlled by varying the MHCD voltage.