Ionization enhancement in radio-frequency plasma thrusters with applied static magnetic fields

The Radio-Frequency Plasma Thruster (RFPT), relying on an electromagnetic coupling mechanism for plasma excitation and energy regulation, offers advantages such as high ionization efficiency, long operational lifetime, wide controllability, and strong system reliability, making it a key development direction in micro-propulsion technology. Experimental studies have shown that wall losses are the critical factor limiting its performance improvement. To reduce wall dissipation and enhance ionization efficiency, this work introduces permanent magnets into the thruster structure, applying an axial static magnetic field to effectively suppress radial plasma diffusion. A multi-physics coupled model was established on the COMSOL Multiphysics^® platform, incorporating plasma, electromagnetic field, laminar flow, and heat transfer modules, to systematically investigate the ionization enhancement mechanism under magnetic confinement. Simulation results demonstrate that, at an input power of 100 W, the electron density increases by approximately 23.8 times compared with the case without magnetic fields; within the power range of 50-1000 W, the electron density exhibits a good linear growth, with a maximum increase of up to 13.7 times. These results confirm the significant regulatory role of static magnetic fields on plasma behavior and provide theoretical support for the design of high-performance RF plasma thrusters.