Hybrid-PIC Simulation on Plasma Flow of Hollow Cathode

Abstract

In order to understand plasma properties of hollow cathodes, a numerical simulation code with Hybrid-PIC model has been developed, in which ions and electrons are modeled as particles and fluid, respectively. In this study, as a first step, the applicability of the model is demonstrated, and then the influences of the emitter temperature on the flow field are discussed for a discharge current of 30 A and a mass flow rate of 1 mg/s. The electron density for the maximum emitter temperature of 1900 K agrees well with the experimental data from JPL. The results also show that the electron density tends to be higher with lower emitter temperature due to the higher electron temperature inside the cathode tube. The higher electron temperature is caused by the energy loss suppression resulting from the higher sheath voltage on the emitter surface. It was also found that charge exchange collisions shift the location of the electron density peak upstream.