The influence of the critical volume on high repetition rate, corona stabilised switching

The PRF performance of spark gap switches can be significantly improved by utilising the phenomenon of corona stabilisation. Using this technique, it is possible to achieve full voltage recovery in spark gaps operating at pulse repetition frequencies (PRFs) of several kHz. One of the factors which is thought to affect the process of corona stabilisation in high repetition rate switches is the critical volume. This paper reports on the parameters which determine the critical volume, and the influence that this has on the PRF performance of plasma closing switches. Among the factors which have been considered are the effect of the highly stressed electrode profile and the gas pressure. The results have indicated that it may be possible to optimise the critical volume in order to enhance the voltage recovery rate of corona stabilised switches.