Preliminary Research on Anode-Cathode Gap Closure Process of a Rod-Pinch Diode

The anode-cathode (A-K) gap closure process of a rod-pinch diode is investigated. The influence of the beam´s self-magnetic field on the motion of anode and cathode plasmas in the Magnetically Limited (ML) phase is analyzed theoretically. The electron pinching process is simulated using PIC (Particle-in-Cell) code. It is shown that stable bipolar flow was formed in the ML phase, the anode and cathode plasmas were restricted within sheaths near the electrodes, and they won´t close the A-K gap. As the input voltage decreases, the beam´s self-magnetic field is not high enough to limit the drift of anode and cathode plasmas which closes the gap and even made the impedance collapse. Sharpening the rising edge of input pulse to achieve the ML phase early or increasing the A-K gap spacing will suppress the short-circuit phenomena caused by plasmas´ drift. The experimental results of the resistive load and the rod-pinch diode are consistent with this understanding.