Methods of improving the pulse repetition frequency of high pressure gas switches

This paper describes several methods which have been developed to improve the pulse repetition frequency (PRF) of high pressure spark gap switches. Under pulse charged conditions, the voltage recovery process of the spark gap has been shown to be restricted by the residual ion population. This may be minimised by applying a suitable bias voltage across the gap. It is also possible to manipulate the V-p characteristic of a spark gap to improve the rate of rise of recovery voltage by reducing the recovery voltage dependence upon pressure. The combination of these effects has been shown to reduce the voltage recovery time of pulsed charged spark gaps from several hundred ms to several ms. Under DC conditions, it is possible to employ a corona discharge, found in a highly nonuniform field, to stabilise and control the voltage breakdown process. The use of corona stabilisation has enabled the operation of a spark gap at a PRF of more than 5 kHz, without employing gas flow techniques.