Precision timing controlled pulsed power current distribution solid state switch array for use in plasma and magnetic field generation

Pulsed power systems are required for producing plasma discharges used in propulsion, fusion, and various plasma formation studies. The activation switch that triggers plasma generation requires transmitting > kA in under a microsecond or faster. Spark gaps are low pressure environment switches that use externally sourced "sparks" to initiate the plasma discharge. Precision timing with spark gaps involves constraining variables, such as the incoming voltage to the switch, switching chamber pressure, distance between switch electrodes, and method of initiating the spark. High current silicon controlled rectifiers, known as thyristors, can be used to handle the dV/dT and dA/dT of capacitor bank powered plasma discharges. An array of thyristors in parallel allows for the current to be distributed according to Kirchhoff's junction rule. This current distribution is dependent on simultaneous triggering of the gate on each thyristor in the array using one signal. Differences in timing can be detected using Rogowski coils around each branch of the array. In this study, timing allowance and tolerance of high current discharges through a thyristor array are investigated for the purposes of producing highly coupled plasma and external magnetic field interactions for magnetic reconnection experiments. The timing from two separate pulsed power systems triggered from one signal was observed to be ~10 ns. This provides six orders of magnitude more timing accuracy and control than a spark gap.