Experimental establishing of plasma opening switch voltage scaling

It is theoretically generalized how the plasma opening switch voltage scaling depends on conduction current. The scaling experimental verification with the megaampere installation GIT-4 is presented. It is found that the peak switch voltage dependence on the conduction current has a nonmonotonic profile: a part of the voltage increase at the switch conduction current less than ~1 МА is replaced by the voltage decrease at the further increasing of the current to the level more than ~1 МА. The change in scaling is due to a different mechanism of magnetic field penetration through plasma: the switch operation regime with plasma erosion dispersal is replaced by the regime of plasma aggregation under the strong magnetic field pressure. As a result, the pulse power arising on current interruption is restricted by the peak voltage reached at the switch current of ~1 МА. The detected switch voltage scaling is also confirmed by the approximation of the experimental data obtained with the megaampere facilities HAWK and DECADE.

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