The attachment and movement of charged particles in the space plasma environment can result in observable potentials on the asteroid surface. This surface charging phenomenon has been extensively studied. However, so far, the influence of asteroid rotation on surface charging and the surrounding plasma has not yet been fully understood. Traditional methods using numerical integration and PIC have slow computation speeds, and mainly focus on the charging mechanisms of static asteroids. In this study, we establish a multi-scale model based on neural networks and the finite element method, thereby improving simulation efficiency and enabling three-dimensional dynamic simulations of rotating asteroids. Simulation results for asteroids with different rotation periods indicate that both the maximum surface potential and the minimum surface potential decrease as the rotation period increases. The minimum potential on the nightside decreases from –4.96 V with one-hour period to –5.97 V with one-week period. For asteroids with longer periods, this downward trend slows down: the period increases from one week to half a year, resulting in a potential change of 0.001 V. Because strong electric field near the the terminator accelerates electrons and ions, electrons respond more promptly to the electric field, owing to their much higher mobility and diffusion coefficient, exhibiting a more severe accumulation phenomenon than ions, resulting in the decrease of the surface potential. This phenomenon is most pronounced when the solar wind is obliquely incident, where the subsolar point is close to the terminator, resulting in the strongest electric field. When the period exceeds one week, this downward trend becomes less pronounced, specifically, the asteroid and plasma have enough time to reach equilibrium at various angles. During the passage of solar storms, there is a significant change in surface potential at different stages, with potential difference caused by rotation periods reaching hundreds of volts. Surface minerals also play a role, with plagioclase being the most sensitive mineral in the exploration, while ilmenite seems indifferent to changes in rotation periods. Understanding the surface charging of asteroids under various rotation periods and angles is crucial for further studying the solar wind plasma and the motion of asteroid’s surface dust, providing a reference for achieving safe landing and exploration of asteroids.
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