Temporal and Spatial Evolution of Self-Pulse in Hollow Cathode Discharge

The temporal and spatial evolution of plasma parameters in self-pulsing discharge is studied experimentally and simulated in a cylindrical hollow cathode discharge structure. Stable self-pulsing discharge is obtained in argon with a pressure of 133 Pa. Taking the measured voltage between two electrodes as the input potential, the self-pulsing discharge in a hollow cathode is simulated by using a fluid model. The temporal and spatial distributions of discharge current, potential, electron density, electric field and net charge density are obtained.Resultsshow that the self-pulsing phenomenon is a transitional process from the discharge mode of low current, low radial electric field, low electron density and low net charge density outside the hole to the discharge mode of high current,high radial electric field intensity, high electron density and high net charge density inside the hole. The transition of discharge mode in different stages of self-pulse is related to the average current. When the self-pulsing discharge is at the peak current, it is a normal glow discharge mode with a strong hollow cathode effect. The discharge mode of the self-pulse at low current is related to the average current. When the average current is low, the self-pulse discharge moves from the anode to the region close to the cathode inside the hole. At this time, when the instantaneous current is the lowest, the discharge is in Townsend discharge mode. When the average current is high, the selfpulse moves from the cathode orifice to the region close to the cathode inside the hole. At this time, when the instantaneous current is the lowest, the cathode sheath near the cathode is basically formed.