Characteristics of multichannel discharge in a coaxial field-distortion switch under nanosecond voltage pulses

Multichannel discharge in gas switches is an effective approach for the reduction of switch inductance, channel resistance and electrode erosion, and the increase of switch lifetime and stability. A coaxial field-distortion gas spark switch was designed and its multichannel discharge phenomena under nanosecond voltage pulses were investigated. The relation between the characteristics of multichannel discharge and the rising rate of pulse voltage was studied. Multichannel discharge characteristics of SF6/Ar mixtures under two mixture ratios were compared. Experimental results show that under a certain pressure the average number of channels increases as the rising rate of pulses increases, and the distribution of current tends to be uniform. The number of channels under a higher pressure is