Investigation on discharge mechanism of a particle beam triggered gas switch

Gas switch plays a key role in the pulsed power system. In this paper, we observed the discharge process of a particle beam triggered gas switch at the lowest working coefficient. The temporal and spatial evolution of particle beam was captured in real time and the velocity curves of particle beam under different gas pressures were obtained. And the triggering mechanism of the gas switch was analyzed. The results showed that, the particle beam moved forward in a bullet mode, and the speed of which increased with the decrease of pressure and decreased with time growing. At the initial time, the speed of the particle beam could reach 3.68×10
⁶
cm/s. The positive and negative streamers were occurred in the triggered gap and particle-beam gap respectively. At the lowest working coefficient 47.2%, the delay time of the two gaps was 34.2ns and 42.1ns, which were basically same as optical diagnostic results. The particle beam triggering was a non-penetrating induced discharge method, and the electric field of the head of discharge channel was enhanced through injecting electrons to the spark gap. The discharge process was accelerated from electron avalanche to streamer, and it was conducive to the rapid closure of the switch.