Proof-of-principle thrust measurement experiments for a partially ionized, electrodeless Magnetic Reconnection Thruster (e-MRT)

To address needs for thrusters with large thrust-to-power, long lifetime, and flexibility in propellant, we are exploring a new electrodeless Magnetic Reconnection Thruster (e-MRT). This concept will use asymmetric, partially ionized, inductively-driven, Alfvénic magnetic reconnection outflows for thrust. Partial ionization may increase power efficiency while maintaining high thrust via neutral-ion coupling. To test the concept, we are performing island merging experiments on the Magnetic Reconnection Experiment (MRX) to measure the thrust from reconnection outflows under various reconnecting magnetic field strengths and gas (argon) pressures. We use Mach probes to measure time-resolved ion flows and an in-vessel flexing beam to measure time-integrated impulse from ion+neutral flows. Measured impulses are tens of μN-s. Initial results suggest that the ion impulse scales with the magnetic energy in the system. Additionally, at high pressures, neutrals may provide significant thrust. We have also run initial Vector Particle-In-Cell (VPIC) simulations of an e-MRT-like geometry, which indicate that downstream magnetic pressure can force the current sheet and outflows to develop asymmetry, generating net thrust. Overall, our findings suggest that reconnection shows promise for application to spacecraft propulsion.