FACTORS AFFECTING AND METHODS OF IMPROVING THE PULSE REPETITION FREQUENCY OF PULSE-CHARGED AND DC-CHARGED HIGH-PRESSURE GAS SWITCHES

The results of this paper describe some of the factors which affect th e repetitive operation of high-pressure gas switches (spark gaps) for both pulse-charged and de-charged operation, Also discussed are method s which may be employed to improve the pulse repetition frequency (PRF ) of spark gaps operating under such conditions, Under pulse-charged c onditions, the voltage recovery process of the spark gap has been show n to be restricted following partial density recovery by the residual ion population. This restriction may be minimized by applying a suitab le bias voltage across the gap to remove the ion influence. It is also possible to manipulate the voltage-pressure (V-p) breakdown character istic of a spark gap in order to improve the rate of rise of recovery voltage by reducing the recovery voltage dependence upon gas pressure, The combination of these effects has been shown to reduce the voltage recovery time of pulse-charged spark gaps from several hundred millis econds to several milliseconds. Under de-charged conditions, where no ''dead time'' is available for voltage recovery, it is possible to emp loy corona discharge effects, which occur in highly nonuniform fields, to stabilize and control the breakdown process. The use of corona sta bilization has enabled the operation of a self-closing spark gap at a PRF of more than 5 kHz, without employing gas flow techniques, A trigg ered version of a corona-stabilized spark gap has also been developed which has demonstrated single run capabilities of 10(7) (4 h continuou s operation at 700 pps) and a lifetime of similar to 10(8) shots (main tenance free, sealed switch). The triggered corona switch has also dem onstrated controlled switching up to a PRF of 1.2 kHz.