Study of the Discharge Mode in Micro-Hollow Cathode

In this study, micro-hollow cathode discharge (MHCD) is investigated by a °uid model with drift-di®usion approximation. The MHC device is a cathode/dielectric/anode sand- wich structure with one hole of a diameter D=200 ¹m. The gas is a Ne/Xe mixture at a pressure p=50»500 Torr. The evolutions of the discharge show that there are two di®erent discharge modes. At larger pD the discharge plasma and high density excited species expand along the cathode surface and, a ringed discharge mode is formed. At smaller pD, the discharge plasma and the excited species expand along the axis of the cathode aperture to form a columnar discharge.