Thermal regime of self-heated hollow cathode in a low-pressure high-current pulsed-periodic discharge

Abstract

We have studied the thermal regime of a self-heated hollow cathode in combined low-current (1–5 A) dc discharge and high-current (up to 100 A) pulsed-periodic discharge and the influence of the pulsed parameters on the current-voltage characteristic of the high-current discharge. It has been shown that, after the application of a voltage pulse (200–500 V), the discharge current attains its peak value and is stabilized over a time of ~100 μs. The discharge voltage in the quasi-stationary discharge stage exceeds the continuous discharge voltage at the same current by many times and depends on the mean value of the current in the discharge gap. The interpretation of the form of the I–V characteristics of the pulsed discharge is based on the dynamics of heating and cooling of the cathode surface layer and on the variations in the integral temperature of the cathode.