The limit of power flow along a high-power MITL

The minimum electrode spacing of the magnetically insulated transmission line (MITL) on the PITHON generator (peak current 4 MA with a 200-ns base-to-base pulse length) is experimentally observed to be limited to 8.0 mm due to current losses occurring after peak current. These current losses limit the minimum inductance, and thus, the maximum possible current produced by existing generators. The scaling of these losses to higher power generators may require an even larger inductance MITL (electrode spacing) limitation. In order to study this limitation, an array of Faraday collectors has been used to measure the loss-current density (A cm⁻²) at several locations along the radially converging PITHON MITL. Results were obtained with both imploding plasma and fixed-inductance loads to determine the effect of V-UV and x-ray radiation on these losses. A comparison of the results from filtered and unfiltered Faraday collectors show that with a 4-mm electrode spacing a significant fraction of the loss current is carried by negative ions.