Study on generation characteristics of plasma jets of multi-electrode in a pulse vacuum discharge

Abstract

Abstract In order to increase the production of plasma jets in a pulse vacuum discharge, based on the insulated anode electrode structure (IAES), discharge experiments by using multiple electrodes under one power supply are performed in this paper. During experiments, discharge currents flowing through multiple cathode sides (cathode currents) were measured by identical Rogowski coils at the same time. The plasma density and propagation velocity of plasma jets were measured by the self-designed ‘+’ type probes. Firstly, the differences in discharge characteristics and generation characteristics of plasma jets between the single-electrode and the double-electrode discharge were compared and analyzed. Secondly, the effects that the electrode spacing (D) and the capacitor capacity had on the discharge characteristics and generation characteristics of plasma jets of the multi-electrode were analyzed. Results show that because the discharge voltage of the IAES is dropped to the arc voltage after a long duration, the simultaneous discharge of multiple electrodes in a single pulse can be realized. Compared with the single-electrode discharge, using multiple electrodes to discharge simultaneously in a single pulse can decrease the initial discharge voltage, increase the peak of cathode current and increase the amount of plasma production. In addition, there is interaction between plasma jets of the multi-electrode, and the spatial electric field generated by the first ejected plasma jet will hinder the generation of plasma jets of subsequent electrodes. Only by keeping a certain electrode spacing (D) between the electrodes, can multiple electrodes be all discharged and plasma jets of the same length be produced. Increasing capacitor capacity can increase the plasma density, propagation velocity, length of plasma jets of the multi-electrode, and realize the simultaneous discharge of more electrodes in a single pulse.