Investigation of plasma opening switch conduction and opening mechanisms

Plasma opening switch techniques have been developed for pulsed power applications to exploit the advantages of electrical energy storage in a vacuum inductor compared to conventional, capacitive-based energy storage. Experiments are described that demonstrate the successful application of these techniques in conduction time ranges from 50 ns to over 1 mu s. Physics understanding of the conduction and opening mechanisms is far from complete; however, many insights have been gained from experiments and theory. Measurements of current distribution, plasma density, and ion emission indicate that conduction and opening mechanisms differ for the 50 ns and 1 mu s conduction times. For the 50 ns conduction time case, switching begins at a current level close to the bipolar emission limit, and opening could occur primarily by erosion. In the 1 mu s conduction time case, limited hydrodynamic plasma displacement implies far higher plasma density than is required by the bipolar emission limit. Magnetic pressure is required to augment erosion to generate the switch gap inferred from experiments.<
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