Equivalent Circuit Model for a Rotating Magnetic Field Thruster Informed by Experimental Data

Electric propulsion (EP) provides a propellant efficient option for deep space exploration. While there are many forms of EP, inductively coupled systems like the rotating magnetic field (RMF) thruster offer several advantages. These include the ability to throttle with minimal loss in performance, high power density, and the ability to operate on reactive propellant. Despite these advantages, this technology is still relatively immature, exhibiting low levels of performance (< 5% efficiency). Model and simulation-based efforts are a critical tool in helping guide efforts to improve this performance. To this end, in this work, an RMF thruster is modeled using a lumped circuit model, accounting for the core circuit components of the thruster and the inductively coupled plasma. The experimental free parameters of this model are then inferred through the use of Bayesian inference and a delayed rejection adaptive metropolis algorithm applied to experimental measurements from a 5-kW class RMF test article. By learning the free parameters of the equivalent circuit model, the ability to make predictions about the efficiency and specific impulse of the thruster is gained. The validated model is then leveraged to perform design optimization studies for future design iterations of the RMF thruster.