Computational and Experimental Study on the Discharge Model of a 20 Amperes Emission Current Hollow Cathode

ABSTRACT

The discharge characteristics of hollow cathode directly affect the performance of thruster. In order to obtain the plasma parameters of the 20 A emission current hollow cathode, COMSOL software is used to simulate the potential distribution, neutral fluid distribution and plasma parameters of the cathode, then the test is carried out to verify the simulations. The results show that the fluid velocity in the emitter region is about 20 ms^–1 and is uniform in the radial direction. The electron density throughout the cathode discharge zone is almost uniform within the range of 1.09 × 10²⁰ ~ 1.2 × 10²⁰ m^–3. The electron temperature increased from 2.8 to 4.9 eV throughout the cathode discharge zone. The electron collision frequency is in the order of 10²³ Hz. The test results show that the electron temperature is increased from 2.4 to 5.2 eV from outlet of the emitter region to the plume region, and which presents an opposite trend to the electron density. There is a small error between the test results and the simulation results, and this error is mainly caused by the flow boundary setting.

Keywords
Cathode discharge; Numerical simulation; Discharge parameters; Plasma diagnosis