Self-Consistent Numerical 0D/3D Hybrid Modeling of Radio-Frequency Ion Thrusters

Abstract

In this paper, we show a numerical model of gridded radio-frequency (RF) ion thrusters. The model consists of a set of self-consistently coupled equations based on conservation of charge, energy, and mass inside the system. Those 0D models are again coupled to a 3D quasi-stationary electromagnetic field solver which offers the opportunity of evaluating arbitrary induction coil and discharge chamber geometries in fairly reasonable simulation time. Several input parameter sets can be computed in parallel due to multi-core implementation. Therefore, the model presented can be regarded as a toolbox for ion thruster engineering purposes and rapid virtual prototyping. The model predicts electrical parameters such as thruster and plasma impedance as well as propulsive performance data. It is thus possible to use it for finding optimized coil and chamber geometries together with optimized input parameters (coil current, volumetric propellant flow rate, and extraction grid voltages) in order to obtain improved mass and electrical efficiency. To prove the validity of the model, performance mappings experimentally performed on a RIM-4 RF ion thruster assembled at the University of Giessen are used to verify the computed data.