Numerical simulation and physical mechanism of spacecraft surface potential regulation via plasma emission

The interaction of spacecraft with space plasma, solar wind, and high-energy particles in the space environment can cause charge accumulation on the surface, leading to risks such as electrostatic discharges and even satellite failure. Emitting a plasma beam into space is an effective method to mitigate this charging phenomenon. In this paper, a coupled model combining particle-in-cell simulation and a spacecraft surface equivalent circuit is used to simulate both natural charging and plasma emission processes. This study analyzes the regulation effect under different parameters and reveals the underlying mechanism. The results indicate that the regulation mechanism lies in the release of a sufficient amount of low-energy plasma from the spacecraft surface. This plasma is driven by electric field forces to expand into space, facilitating charge transport between regions with large potential differences. This process alters the current balance of the spacecraft surface, thereby realizing global potential regulation. Therefore, a sufficiently large emission current and low plasma energy are key conditions for effective regulation. Furthermore, this study highlights the indirect contribution of secondary electron emission in mitigating differential charging and achieving potential equilibrium under the influence of plasma emission.