Enhanced spark gap switch recovery using nonlinear V/p curves

A method of improving the voltage recovery time of high pressure gas switches is described and demonstrated. By changing the electrode geometry of a normally uniform field switch, it is possible to suitably alter the breakdown voltage/pressure (V/p) characteristic. The desired V/p characteristic for improved voltage recovery is one which exhibits two different rates of rise of breakdown voltage with pressure, such that at high enough pressures, the breakdown voltage becomes almost independent of pressure. Full voltage recovery may then be achieved during the fast dV/dp section of the curve while only partial pressure recovery is achieved. This effect is demonstrated in a switch filled with SF₆. An improvement in the voltage recovery time of greater than 10 ms to ~1 ms was observed when the operating pressure was increased from 3-6 bar