The interelectrode breakdown mechanism and discharge characteristics of the electrospray thruster

Abstract

In the actual working process of electric thrusters based on high-voltage electric fields, the discharge breakdown phenomenon is universal and complex, and such phenomena will have a significant impact on the thruster structure, working state and spacecraft system. In order to study the interpolar discharge breakdown characteristics of ionic liquid electrospray thrusters, a basic electrospray model and test system were constructed, and the change curves of discharge characteristic parameters such as breakdown voltage, threshold current, breakdown voltage frequency and so on in the range of 7×10−3~105 Pa with air pressure and transmitter inner diameter were obtained, and the air pressure range that the electrospray model could work in normally was calibrated. The results show that the breakdown voltage characteristic curve of the electrospray model has typical minimum characteristics, and the minimum values all appear around 80 Pa. Lowering the air pressure below 10−2 Pa can effectively increase the breakdown threshold between the poles and the emission current, thereby obtaining a larger voltage regulation range, and when the air pressure is reduced to 7×10−3 Pa, the breakdown can reach more than 3200 V. The 60-μm inner diameter emitter performed better in the discharge experiment, and the breakdown threshold, emission current and operating area range were better than the slightly larger inner diameter emitter under the same working conditions.