Experimental Investigation of the Electrical Wiring Configuration of the HK40 Hall Thruster Operation

ABSTRACT

Vacuum chambers providing a low pressure environment similar to the vacuum environment in low earth orbit have been used for the testing of plasma thrusters. A significant proportion of research on the effects of vacuum facility on plasma thrusters has focused on the effects of background pressure and plume expansion; however, the electrical interaction of the conductive chamber walls with the plasma thrusters needs to be explored further. In this study, the operation of a prototype Hall thruster, HK40, was investigated to understand the effects of wiring configuration of the thruster-cathode-chamber system. During the tests, the thruster was operated in two different grounding configurations. A resistance analogy regarding the changes in the electrical potentials and measured currents was introduced. The calculated thrust and efficiency values of the two configurations were compared. This study shows that the current extracted from the emitter surface of the cathode, along with the cathode-to-ground voltage can be used to estimate the thrust and thruster efficiency. In addition, the theoretical predictions were compared with the values based on the measurements made with an in-house-built inverted pendulum type thrust stand. The presented results show that the thrust and efficiency values are predicted with 3.4% and 8.3% uncertainty, respectively.

Keywords
Electric propulsion; Hall thrusters; Vacuum chambers; Hollow cathodes