Numerical research of a 2D axial symmetry hybrid model for the radio-frequency ion thruster

Abstract

Since the high efficiency discharge is critical to the radio-frequency ion thruster (RIT), a 2D axial symmetry hybrid model has been developed to study the plasma evolution of RIT. The fluid method and the drift energy correction of the electron energy distribution function (EEDF) are applied to the analysis of the RIT discharge. In the meantime, the PIC-MCC method is used to investigate the ion beam current extraction character for the plasma plume region. The beam current simulation results, with the hybrid model, agree well with the experimental results, and the error is lower than 11%, which shows the validity of the model. The further study shows there is an optimal ratio for the radio-frequency (RF) power and the beam current extraction power under the fixed RIT configuration. And the beam extraction efficiency will decrease when the discharge efficiency beyond a certain threshold (about 87 W). As the input parameters of the hybrid model are all the design values, it can be directly used to the optimum design for other kinds of RITs and radio-frequency ion sources.

Analysis of influencing parameters in ion thruster plume simulation

“…Ion thrusters feature very high specific impulse (from 2000 to over 10,000 s) and efficiency (from 60% to over 80%) compared to the commonly used electric thrusters such as Hall thrusters. [1][2][3][4] However, in addition to the excellent performance of ion thrusters, effects from ion thruster plume have long raised concerns, such as interference torque, sputter erosion of surface materials and deposition of eroded thruster materials onto sensitive parts of the spacecraft. The ion thruster plume mainly contains the following particles: high-energy beam ions, low energy charge exchange (CEX) ions, electrons, sputtered particles, and unionized neutral atoms.…”