Plasma opening switches

A Plasma Opening Switch (POS) is a configuration used for fast switching of very high current pulses (100 kA to 10 MA). The principle of operation is shown in the picture.

Pre-injected plasma is conducting for a certain time, 50 ns - 1 microsecond, and then diverts the current to a parallel load. The plasma functions as an opening switch, which is closed during conduction and then opens to high resistance. The opening time is much shorter (typically by 5-10 times) than the rise time of the current pulse without the POS. The shortening of the pulse duration causes a compression of the energy and as a result - an increase in the load power.

Two different types of switches are operational in our laboratory: a coaxial POS and a planar POS.

POS's are used to drive pulsed-power plasma devices, such as:

• Z-pinches for radiation production
• Ion diodes to generate high-power ion beams
• Electron diodes to generate energetic electron beams

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