Improving the performance of glow discharge hollow cathode by using low work function materials

Abstract Hollow cathodes are widely used as neutralizers in electric propulsion. Currently, with the trend of satellite miniaturization and diversification of space missions, alternative neutralization technology based on new materials and alternative propellants has become a hot topic. This study compared the discharge characteristics and performance of different cathode materials LaB 6 and 304 stainless steel in a direct-current glow discharge hollow cathode (GDHC). Numerical and experimental investigations were conducted on the inner discharge region and outer plume region of the GDHC to analyze the plasma behavior, respectively. Experimental results show that the LaB 6 configuration (adding a LaB 6 insert into the 304 configuration) can effectively reduce the discharge power cost and improve the gas utilization factor. An anode current of 213.6 mA was achieved at 2 sccm of argon in the LaB 6 configuration, corresponding to a discharge power cost of 182 W A −1 and a gas utilization factor of 1.5. The LaB 6 configuration exhibits a higher discharge current, resulting in a higher plume plasma density. The simulation results show that the electron density and ion density in the cathode fall (CF) region near the LaB 6 insert increase significantly, thereby improving the electron and ion conductivity, and effectively reducing the CF voltage. Comparison reveals that the performance of the GDHC (LaB 6 ) is comparable to RF cathodes and microwave cathodes with argon propellant.