Simulation study of excimer VUV emission from xenon microhollow cathode discharge in the self-pulsing regime

Abstract

A volume-averaged model is employed to study the dynamics of a microhollow cathode discharge in xenon operating in the self-pulsing regime. The numerical results revealed that the discharge voltage initially increases during the abnormal mode when the discharge current is quite low. Then, the discharge is transferred to a normal mode in which the current shows a steep growth to extremely high values. The results also indicated that the self-pulsing frequency increases with an increase in the input voltage at constant pressure. However, an increase in pressure at a constant input voltage leads to a reduced self-pulsing frequency. The strongest vacuum ultraviolet emission is attributed to xenon triplet excimers at a wavelength of 173 nm. An increase in the input voltage enhances the average densities of the xenon excimers, but has almost no effect on the maximum densities. Compared to the input voltage, an increase of the pressure has a much stronger effect on both the maximum and average densities, such that the maximum density of the triplet excimer is increased from 1.48×1017 m−3 at P = 30 Torr to 2×1021 m−3 at P = 250 Torr. A comparison between the self-pulsing and stationary regimes shows that the maximum densities of the excimers at the self-pulsing regime are an order of magnitude higher than those of the stationary regime. Furthermore, the average densities of the excimers in the self-pulsing regime are higher than those of the stationary regime at higher input voltages. However, the reverse is true for lower voltages.