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: