Background Self-breakdown water switches are core components of pulsed power facilities. Conduction inductance of these switches directly determines the rise time of the load current.

Purpose To meet the requirement for shortening the load current rise time for a 10 MA pulsed power facility, reducing the conduction inductance of the self-breakdown water switch was identified as an effective solution. The target is to reduce the conduction inductance from 150 nH to 120 nH.

Methods Increasing the number of conduction channels is an effective approach to reduce the conduction inductance of self-breakdown water switches. Theoretical calculation results show that a six-channel self-breakdown water switch structure can reduce the conduction inductance to 115 nH. According to Martin's semi-empirical criterion, the feasibility of six-channel discharge for the designed switch was preliminarily verified with three parameters: the voltage rise time derived from the inductance parameters, the transit time between adjacent electrodes, and the single-channel jitter time. Based on this assessment, the six-channel self-breakdown water switch prototype was fabricated, and verification experiments were carried out on the 10 MA pulsed power facility.

Results Experimental results show that stable and bright discharge channels can be formed in all six electrode gaps under an operating voltage of 3 MV, which verifies the feasibility of the six-channel self-breakdown switch. According to the measured voltage waveforms, the voltage rise time at the inlet of the tri-plate transmission line is 36 ns, which is 18 ns shorter than the 54 ns rise time of the previous three-channel switch under the same load condition. The actual conduction inductance of the six-channel switch is estimated to be 118 nH.

Conclusions The designed six-channel self-breakdown water switch can effectively reduce conduction inductance and shorten the load current rise time, which fully meets the expected experimental requirements.