Numerical study of plasma-fluid characteristics and thrust performance of a low-power argon inductively coupled plasma electrothermal thruster

Abstract

Low-power (from the sub-kilowatt range up to a few kilowatts) inductively coupled plasma (ICP) electrothermal thrusters for space propulsion are potential alternatives to low-power arcjet thrusters, which are often implemented on geostationary satellites for north–south station keeping. We develop an axisymmetric two-dimensional magnetohydrodynamic (MHD) numerical simulation technique using a two-temperature plasma model as a computer-aided engineering tool for low-power argon ICP electrothermal thrusters. Furthermore, to the best of our knowledge, this is the first study to provide a basic understanding of the plasma-fluid characteristics of low-power ICP electrothermal thrusters. To this end, we perform the MHD numerical simulation for a low-power argon ICP electrothermal thruster model that was developed for thrust measurement experiments to validate the proposed numerical simulation technique. The numerical results indicate that the plasma flow produced in the low-power argon ICP electrothermal thruster model is basically in a strongly thermal and ionizing nonequililbrium state. In addition, the numerical results show that the experimentally measured thrust forces can be reproduced with an underestimation of 10% or less over the RF input power range of 0–0.6 kW considered in the experiment. Moreover, the numerical results suggest that the main reason why the performance of the low-power argon ICP electrothermal thruster model is significantly lower than the target performance is the considerable heat loss of more than 90% of the input power through the flow-channel wall.