Numerical investigation of plasma behavior in a micro DC ion thruster using the particle-in-cell/Monte Carlo collision (PIC/MCC) method

Abstract

Micro direct current (DC) ion thruster has advantages of small volume, light weight and significantly improved specific impulse performance compared to conventional chemical propulsion systems, thus having a wide application prospect in the tasks of cube-satellites and micro satellite networking systems. In this paper, a two-dimensional axisymmetric particle-in-cell/Monte Carlo collision model for the discharge chamber is developed for a micro DC ion thruster, which adopt the real configuration of original MiXI thruster with ring-cusp magnetic field. This model takes the thermal electron emission including the Schottky effect, various collision processes and the uneven background gas density distribution in the cathode-anode gap into account. The transient discharge process and the influence of operating conditions on the discharge process in the ionization chamber are presented for the first time so as to provide a detailed understanding of transport characteristics of plasma associated with the DC discharge process. Our calculated properties are compared with literature experimental data under similar conditions and qualitative and quantitative agreements are reached. The leak widths for charged species are obtained and closely related to charge separation. The simulations indicate that low neutral flow rate may lead to a discharge instability accompanied with oscillation of plasma quantities. These results lay a foundation for further optimization of thruster discharge chamber design in the future.