Effect of electron temperature on dynamic characteristics of two-dimensional sheath in Hall thrusters

The Debye sheath has a significant effect on the performance of Hall thrusters. The dynamic characteristics of the two-dimensional sheath is investigated using the 2D-3V particle-in-cell method in this paper. The numerical results show that while the sheath exhibits the one-dimensional stability when the electron temperature is relatively low, it behaves as a two-dimensional (both in time and space) oscillating characteristic when the electron temperature is high. Moreover, it is found that the oscillating frequency is the same order as the electron plasma frequency and the spatial wavelength is equal to the length of the electrostatic wave.