Research on the Enhancement of Ionization in RF Plasma by Additional Static Magnetic Fields

RF electric propulsion relies on electromagnetic coupling mechanisms to achieve plasma excitation and energy control, featuring advantages such as high ionization efficiency, long service life, broad adjustment capabilities, and strong system reliability, making it an important development direction in micro electric propulsion technology. Experimental studies indicate that wall dissipation is a key factor limiting performance improvement. To reduce wall losses and enhance ionization efficiency, this paper introduces permanent magnets into the thruster structure, applying an axial static magnetic field to effectively suppress the radial diffusion of plasma. Based on the COMSOL Multiphysics® platform, a multiphysics coupling model is constructed, integrating plasma, electromagnetic fields, laminar flow, and fluid heat transfer modules to systematically study the ionization enhancement mechanism under permanent magnetic confinement. Simulation results show that at 100 W input power, the electron density increases by approximately 25.6 times compared to the condition without a magnetic field; within the 50−1000 W power range, the density growth exhibits a good linear trend, with a maximum increase of 13.7 times. The results validate the significant regulatory effect of static magnetic fields on plasma behavior, providing theoretical support for the design of high-performance micro RF thrusters.