Revisiting the Plasma Magnet Sail: an Enabling Technology for Fast Interplanetary Travel

Magnetic sails which utilize solar wind particles for propulsion are not limited by the Tsiokovsky rocket equation, nor by the material constraints that limit the acceleration of photon sails. This gives them the potential to enable interplanetary transit speeds up to hundreds of kilometers per second. The plasma magnet sail, a magnetic sail concept originally developed by John Slough, uses a rotating magnetic field to induce a ring current in the plasma surrounding a spacecraft. It is found to have several drawbacks which limit its performance so much that it is uncompetitive with electric thrusters. However, a modified version attempts to address these flaws. A Hall-MHD model of the original and modified plasma magnet was created using the NIMROD code, modified to include some effects of the anomalous resistivity encountered at low density. The total magnetic moment, and corresponding thrust generated by the sails were estimated at multiple scales corresponding to different mission classes. Although there are many outstanding questions to answer, to fully investigate the viability of the modified plasma magnet, it does suggest a path to a high-thrust, nearly propellantless propulsion system for use outside of Earth's magnetosphere.