Dynamic 3D Simulation of Surface Charging on Rotating Asteroids

Abstract The surface-charging phenomenon of asteroids, mainly resulting from solar wind plasma and solar radiation, has been extensively studied. However, the influence of the asteroid’s rotation on surface charging is not yet fully understood. In this study, a neural network is established to replace numerical integration, improving the efficiency of dynamic 3D simulations. We simulate rotating asteroids and their surrounding plasma environments under various conditions, including the quiet solar wind and solar storms. Different minerals on the asteroid surface are also considered. Additionally, the effects of orbital motion and obliquity are studied for asteroids with rotation periods comparable to their orbital periods. The results show that under the typical solar wind, the maximum and minimum potentials of asteroids gradually decrease with increasing rotation periods, especially when the solar wind is obliquely incident. For asteroids with rotation periods longer than one week, this decreasing trend becomes extremely slow. During a solar storm, the solar wind plasma changes sharply, and the susceptibility of an asteroid’s surface potential to rotation is greatly pronounced. Surface minerals also play a role; plagioclase is the most sensitive mineral among those explored, while ilmenite appears indifferent to changes in rotation periods. Understanding the surface charging of asteroids under various rotation periods and angles is crucial for further research on solar wind plasma and asteroids’ surface dust motion, providing a reference for the safe landing and exploration of asteroids.