Influence of operating parameters on high-pressure microhollow cathode discharge with a cylindrical hole

As a promising candidate for generating large-scale plasma at high pressure, microhollow cathode discharge (MHCD) with a cylindrical hole has been numerically simulated at an argon pressure higher than 50 Torr by a two-dimensional particle-in-cell Monte Carlo collision method. Results indicate that MHCD is operated in a confined phase at the beginning, which transits to an expanded phase and reaches a steady-state at about 160 ns. In a steady-state MHCD, the majority of electrons have a low energy of several eV, and some electrons have a high energy up to 480 eV. High-energy electrons mainly appear adjacent to the cathode surface. With increasing applied voltage, there is a transition from the confined phase to the expanded phase for a steady-state MHCD. Moreover, maximal density of charged particles increases for the expanded phase with increasing applied voltage and argon pressure or decreasing hole diameter. Besides, discharge morphology has been investigated in detail with varying operating parameters. All these results have been compared with those simulated by the fluid model.