Influence of electrode geometry on X-ray emission, plasma inductance, voltage, and current derivative signals obtained from a plasma focus device

Abstract

Plasma focus devices have been investigated as a pulsed radiation source. Different studies have shown that the shape of the anode affects strongly the plasma dynamic and X-ray emission that takes place in plasma focus devices. In the present work, a hybrid-type plasma focus device (6 μF, 16 ± 1 kV), named PF-2kJ, is operated at various pressures of hydrogen gas with five cylindrical anodes of the same lengths but different in shapes, without cathode bars. The effect of cathode bars on various electric parameters is studied for the anode that has the maximum X-ray emission. The electrical signals of Rogowski coil (current derivative), voltage divider (voltage at the anode), and photomultiplier tubes (X-rays) were analyzed for all the anodes. Inductance and the voltage at the time of the pinch were derived from the measured voltage and current derivative signals. The X-ray dose measurements were performed using thermoluminescent dosimeters (TLD-100). The PF-2kJ performance is not the best while using the cathode bars. Our results show that by changing the anode shape just over the insulator sleeve the plasma focus devices can be switched between close energies stored in the capacitor bank.