Parallel operation of microhollow cathode discharges

Summary form only given. Microhollow cathode discharges (MHCDs) are high pressure gas discharges between a cathode, which contains a circular opening and an arbitrarily shaped anode. The diameter of the cathode hole as well as the electrode gap is approximately 100 /spl mu/m. Operation on such a small spatial scale enables stable direct current glow discharge operation even at high pressure. Microhollow cathode discharges have been operated at atmospheric pressure in rare gases (e.g., argon, xenon), rare gas halogen mixtures (e.g., argon fluoride, xenon chloride) and in air. Stable dc high pressure glow discharge operation is of interest in lighting, plasma processing, and as plasma cathodes for air plasma ramparts. The required plasma size for these applications exceeds that of a single microhollow cathode discharge and therefore requires their arrangement in arrays. Parallel operation of up to sixteen micro discharges has been reported using distributed ballast. A simpler way to generate arrays is to operate the glow discharges in a range where the voltage current characteristic has a positive slope, e.g. In the abnormal glow region. This can be achieved by limiting the cathode surface to a small value such that even at low currents it is completely covered by the plasma. In order to reduce the cathode area, the cathode surface was covered with a dielectric, such that only the cylindrical surface area of the cathode opening was available as cathode.