Study on Underwater Nanosecond Surface Discharge Driven by Magnetic-switch-based Repetitive Pulsed Power Supply

In recent years, compact and small-scale pulsed power driving sources have been increasingly developed, providing more flexible and controllable physical effects such as acoustic and electromagnetic waves generated by underwater pulsed discharge. This paper presents a platform for achieving underwater low-energy, high-repetition-rate discharges. It utilizes a magnetic-switch-based circuit and a multi-stage charging adjustable pulsed power source to drive nanosecond discharges in water. A surface discharge load employs thin copper sheets as electrodes, with discharge materials sprayed or adhered to the substrate. The surface discharge characteristics of the load under this power source are analyzed through a combination of electrical and high-speed shadowgraph images diagnostics. The results show that the voltage transformation ratio of the power module can reach 1:27. When the load is not discharged, the ratio of the second-stage charging voltage to the first-stage charging voltage can reach 6:5. The rising edges of the load voltage and circuit current within 100 ns, the discharge period is within ~1 us. The circuit current is in 10
²
A level, with discharge power reaching the 10
⁶
W level. Significant bubble effects are observed from the surface discharge, and the discharge exhibits good repeatability. These results lay the groundwork for further generating underwater low-energy multi-physical field sources and provide insights into exploring high-repetition-rate discharge loads in water.