Effects of Magnetic Circuit Temperature on Discharge Thermal Stability of a Hall Thruster

In order to clarify the effects and intrinsic mechanism of high magnetic circuit temperature on the thermal discharge instability of a Hall thruster, an experimental study on the working magnetic field intensity of the thruster at different magnetic circuit temperature was carried out. Meanwhile, a Particle-in-Cell simulation was performed on the interaction between the change of magnetic circuit temperature and the change of plasma discharge behavior. The experimental results show that when the magnetic circuit temperature rises from room temperature to 600℃, the working magnetic field intensity of the thruster is attenuated despite that the attenuation is not significant (about 5%). The simulation results show that the attenuation of magnetic field intensity, caused by the high magnetic circuit temperature, changes the distribution of electron cross-field mobility as well as electric potential, and consequently impacts the distributions of electron energy, particle density, and et al. As a result, both the flux and the energy that electrons loss on the channel walls are promoted, which dominates the variation of total deposition power and thus exacerbates the increase of magnetic circuit temperature. This is a process with a matter of positive feedback, therefore, if the magnetic circuit temperature cannot be controlled effectively, the thruster discharge would be unstable.