High-Voltage Pulsed-Power Supply Operating at Repetitive Discharge Mode for Driving Very Small Plasma Focus Devices

The technology of switched-mode power supplies (SMPSs) has been employed to design and build a much simpler and portable high-voltage pulsed-power supply (HVPPS) as an efficient pulse drive unit for very small plasma focus devices (PFDs). The HVPPS is designed in such a way that it is able to charge a low-energy capacitor bank (84 nF, 7 kV, 2.1 J), from 4 to 7 kV at a repetitive discharge mode of 5 Hz. All control processes are carried out via a laptop through a graphical interface, written in C# language. The experimental runs were carried out in argon at 4-mbar gas pressure and the 7-kV maximum charging voltage level of the HVPPS. The results of diagnostics at a repetitive discharge mode of 5 Hz successfully confirmed the accurate performance of the SMPS and the spark gap switch for driving a very small PFD. The rise time of 10%-90% of the charging voltage, at each single-shot trace was obtained to be 110 ms. This consequence demonstrated that the control and sampling circuits were being implemented as well. After discharging, the pinching evidence was genuinely observed in the capacitor bank voltage trace. The quarter period of the discharge traces was observed to be 100 ns, which leads to a total system inductance of about 48 nH. The measured inductance was low enough to be compatible with successful performance of the very low energy PFD, leading to fast and high magnitude discharge pulses to assist the pinching evidence. This HVPPS could emerge as one of the very low cost, compact, light weight, and highly efficient power supplies used for driving the very small PFDs so far.