Study on discharge oscillation in a cusped field thruster

Abstract

A cusped field thruster with adjustable magnetic field strength is designed by Harbin Institute of Technology (HIT). The thruster produce thrust by accelerating the xenon ions in the electric field. Two different modes are found during the experiments, one is high anode current and low voltage mode, the other is low anode current and high voltage mode. Phenomena of intermittent large amplitude anode current oscillation are observed during the period when we change the operational mode. During the experiments the large amplitude and low frequency anode current oscillation is a significant feature when the thruster operates under high anode current and low voltage mode. This anode current oscillation reduces the performance of the thruster, and also some significant effects on the anode current and plume of the thruster has been found because of the low frequency current oscillation under two different operational modes. Under low anode current operational mode, the intermittent images at the channel exit are recorded by a camera. The connection between the position of bright ionization zone of plasmas and the position of magnetic field cusps is established by qualitatively analyzing the phenomena observed in the discharge channel. The performance of the thruster is improved by adjusting the magnetic field configurations and reducing the magnitude of oscillation.