Microsecond plasma opening switch performance at currents above 2 mA

A coaxial geometry plasma opening switch (POS) has been tested on the 4 MJ ACE 4 pulsed power driver. Simple models of POS operation were used to scale successful results from drivers such as HAWK at NRL and ACE 1 which operate at the desired conduction time but at currents below 1 MA. For the conduction phase, a snowplow model indicates that the square root of the plasma density is proportional to the product of conduction time and peak conduction current for fixed radius and length switches. This relationship was verified for the ACE 4 POS. For the opening phase, a model of gap formation enabled plasma density thinning during the conduction phase was applied. The gap distance can be estimated from the voltage and current measurements using a magnetic insulation model.