Investigation of the physical process inside the crater during the ablation of the cathode material of a micro-cathode arc thruster

Abstract

In this paper, the relationship between the morphology of the cathode crater and plasma ionization between thrusters is studied by adjusting the input energy of the micro-cathode arc thruster (μCAT). We monitor the morphology of the cathode crater of the μCAT using scanning electron microscopy and explore the relationship between the crater morphology and the internal energy loss of the cathode crater. This relationship, combined with the numerical simulation results, is used to monitor the ionization between the electrodes of the μCAT using an enhanced intensified charge coupled device spectrum detector. The effect of cathode crater morphology on the ionization of the propellant during the operation of the μCAT is determined. The results show that with a change in the input power processing unit voltage, the external profile and depth-to-diameter ratio of the cathode crater change, resulting in a change in the internal energy loss of the thruster cathode crater and then affecting the ionization efficiency of the cathode working fluid in the μCAT. Under the condition of basically unchanged cathode feed energy flow density, reasonable adjustment of the depth-to-diameter ratio of the cathode crater can effectively improve the ionization efficiency of the cathode working fluid in the μCAT.