Equivalent Circuit Model for a Rotating Magnetic Field Thruster

A lumped circuit model approach is used to predict performance of a rotating magnetic field (RMF) thruster. The equivalent circuit is derived by modeling the driving antennae and plasma as a collection of current loops interacting via mutual inductance and Lorentz forces. Several physically relevant assumptions are applied to reduce the complexity of the system. The resulting set of equations require five free circuit parameters that must be determined experimentally. Data from performance measurements of the Plasmadynamics and Electric Propulsion Laboratory (PEPL) RMF v2 thruster is used to calibrate the model. While the model tends to underpredict performance, it mirrors operational trends observed during the experiment. Thruster performance is discussed in the context of the fundamental scaling of the model as well as the individual scaling of the free parameters. Several methods for increasing performance are proposed, including ncreasing specific energy, flow rate, and background magnetic field strength to achieve higher impulse and efficiency.