Effects of cathode operating parameters on the ignition voltage threshold of Hall thrusters

• Published in: Vacuum Vol. 174; p. 109169
• Main Authors: Li, Wen-Bo, Li, Hong, Ding, Yong-Jie, Wei, Li-Qiu, Yang, Xin-Yong, Cai, Hai-Kuo, Sun, Jian-Ning, Yu, Da-Ren
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.04.2020
• Subjects: Cathode operating parameters; Hall thruster; Ignition voltage threshold; Langmuir probe; Cathode operating parameters; Langmuir probe; Hall thruster; Ignition voltage threshold
• ISSN: 0042-207X; 1879-2715
• DOI: 10.1016/j.vacuum.2020.109169

Changing the operating parameters of a cathode affects the ignition process of a Hall thruster mainly by changing the micro-plasma parameters emitted by the cathode at the moment of ignition. However, the micro-plasma parameter that dominates this effect is not clear. Therefore, the ignition voltage thresholds with different cathode operating parameters were first measured. Then, to better understand how these operating parameters affect the ignition voltage threshold of a Hall thruster, the two-dimensional distribution characteristics of the electron density, electron temperature, and plasma potential in the cathode plume region were measured using a Langmuir probe. The results showed that increasing both the keeper current and mass flow rate of the cathode causes an increase in the electron density emitted by the cathode and a decrease in the electron temperature. It was also found that increasing the cathode mass flow rate has a more pronounced effect than increasing the keeper current. Furthermore, when both the mass flow rate and keeper current of the hollow cathode are increased, the ignition voltage threshold of the Hall thruster decreases significantly. This is mainly because of a significant increase in the electron density resulting from the increases in the mass flow rate and keeper current. •The effect of cathode operating parameters on the ignition process of HET is studied.•The ignition voltage thresholds of HET under different operating parameters are given.•A Langmuir probe was used to measure the plasma parameters of cathode plume.•The plasma parameters at different operating parameters of cathode plume are given.•The change of cathode operating parameters related to different plasma parameters.