Investigation of a multichanneling, multigap Marx bank switch

Abstract

There is increasing interest in the pulsed power community for understanding the complex phenomena of multichannel spark gap switches. Extracting the potential advantages of these switches is necessary for upgrades to large, high current, high voltage machines. A previously designed, multichanneling spark gap (MCSG), with toroidal electrodes, for Marx bank applications, is investigated to determine which factors effect its multichannel operation. To date, thorough research does not exist for multichanneling gas switches with toroidal electrode geometry. The following results are the first of their kind. Gas type, gas pressure, trigger voltage, and trigger polarity are varied to study their effects on multichanneling in the MCSG. The fill gas is varied between air and an Ar/SF6 (90%/10%) mixture, from 3 to 10 psig. There are more channels for the mixture than for air for similar pressures. Trigger voltage amplitude and polarity are varied negatively from −60 to −100 kV and positively from +75 to +95 kV. Trigger polarity more drastically effects the distribution of arcs on the electrode rings of the MCSG rather than the number of channels. Output current is examined to determine if there are any significant decreases in rise time by increasing the number of channels. It is determined that there is very little dependence of output current on the number of channels observed in a typical Marx configuration for the MCSG.