A Thyristor Switched Pulsed Power System with a Coaxial Plasma Gun

A first of a kind fiber-optically controlled and thyristor switched coaxial plasma gun pulsed power system has been designed, built, and fired at up to 2 kV and 6.4 kA, with a 6.65 MW momentary peak power output from the capacitor. Total system firing jitter from initial digital signal to 90% peak current rise has been measured at 78.15 ns, representing 0.18% of the total pulse time of 44.10 µs. This includes both thyristor turn-on and coaxial plasma gun breakdown. Standard deviation of peak current over repeated firings has been measured to be 21.09 A (0.33%). The system has experienced 100+ firings at 2 kV without a single misfire. A voltage profiling analysis has been performed where voltage differentials across system components, including the thyristor, were collected temporally for the entire pulse. High speed and long-exposure photography was used to verify coaxial plasma gun operation and mass-injection/gas-puff system timing. This study sets the groundwork for plasma-load pulsed power systems using thyristors, as well as informing expanded voltage and current capability, enabling fine timing control and multi-system synchronization, allowing greater repeatability and reliability, as well as informing multi-thyristor array systems.