Investigation of electron and ion flows in the microsecond plasma opening switch on the terawatt power level

The results of an investigation of ion and electron flows in a coaxial microsecond plasma opening switch (POS) are given. A 1-μs front duration POS with outer and inner electrodes with diameters of 210 mm and 75 mm, respectively, switched a 1-MA pulse during 0.1 μs to a 120-cm-long short-circuited coaxial line with matching diameters. The polarity of the inner electrode was negative. The plasma of the POS was injected from the outer electrode by 32 plasma guns of capillary type. The typical POS voltage was 0.9-1.2 MV. The calculated energy losses in the POS during the switching phase reached 0.1-0.15 MJ. The location and distribution of the heat absorbed along the POS electrodes were determined. Measurements of electron flow showed that heat energy absorbed by the POS anode (which made up 30-40% of the total energy losses in the POS) did not affect the flow. Nuclear activation measurements showed that the energy of the convergent proton flow was in good agreement with the voltage generated in the POS and that almost all of the energy input in the inner electrode could be provided by intense ion flow.