Overview of researches on oscillations in hall thrusters

Since Hall thrusters' application in 1971 in the former Soviet Union, Hall thrusters due to their high performance are now considered as one of the preferred candidates for satellite orbit keeping and transferring. The instabilities of discharge plasma ranges from kHz to GHz including many kinds of physical phenomena and playing a major role in the process of ionization, diffusion and acceleration of particles are usually the hotspot issues. The research results about oscillations in Hall thrusters are overviewed in this paper. Based on our knowledge and investigation, some problems which still need to be resolved have been proposed. All of these are useful for the further research about oscillation in Hall thrusters.