Microsecond conduction time POS plasma characterization [pulsed power]

The plasma behavior of the plasma opening switch (POS) in inductive energy storage pulsed power generators was studied by optical interferometry. A cable plasma gun was used as the most conventional plasma source for experiments. The characterization of cable gun plasma allowed the determination of the initial plasma conditions for the switch. Time- and spatially resolved density measurements are performed in the plasma opening switch, showing the density drop during switch opening almost in the whole interelectrode gap. The gap formation process is found very unstable even in one dimensional switch geometry. The plasma density diagrams are compared to major switch characteristics such as conduction time and load current dI/dt. The study of spectral line intensities from cable gun plasma showed that CII line intensity correspond in time to plasma density measured by interferometer. The intensities of carbon spectral lines tend to drop during switch opening, that substantiates interferometry measurements.