High power graphite two-electrode spark gap switch

Two-electrode spark gap switch is an important candidate for the switching element of huge high laser power supply systems. This paper presents the using condition and critical technology of graphite two-electrode spark gap switch. The electrical field strength simulation shows that the electrode shape which satisfies Borda profile could constitute the optimized spark gap. Referred to the known parameters about the ST-300 switch used in NIF, a series of electric tests have been done. The tests have proved that the graphite two-electrode spark gap switch can support 300 kA peak pulse current, with over 100 C transfer charge and over 1 000 shots of lifetime, therefore meeting the requirement of the 1.2 MJ huge laser power supply system.