The injected plasma triggered breakdown of the trigatron spark gap.

This paper presents experimental results on a trigatron spark gap breakdown process induced by different densities of the injected plasma. The results show that the shape of the injected plasma has a great influence on the electric field distribution. The decrease in the curvature radius of the injected plasma front can induce a breakdown during the dissipation of the injected plasma. This process is significant in explaining the sharp increase in the breakdown delay and jitter observed under very low working coefficients. The inception and propagation of the streamer are studied in detail. Due to the high intensity illumination, direct ionization between the injected plasma front and the head of the streamer can occur during the propagation of the streamer. This differs from the conventional streamer breakdown process under a uniform electric field. An explanation of the streamer inception and the direct ionization between the front of the injected plasma and the streamer head is presented. Using the Meek criterion, the effects of electric field distortion and photoionization induced by the injected plasma are analyzed. The results indicate that the effect of the photoionization changes significantly with the density and duration of the plasma injection. Combining this effect with the electric field distortion, a breakdown can occur under a very low working coefficient. [ABSTRACT FROM AUTHOR]