Dynamic Three-dimensional Simulation of Surface Charging on Rotating Asteroids

TL;DR

This study uses neural networks to efficiently simulate how asteroid surface charging varies with rotation, solar wind conditions, and surface minerals, revealing key dependencies relevant for asteroid exploration safety.

Contribution

It introduces a neural network-based method for dynamic 3D simulation of asteroid surface charging, incorporating rotation, plasma environment, and mineral effects, enhancing simulation efficiency and detail.

Findings

Surface potential decreases with increasing asteroid rotation period.

Solar storms significantly amplify the effect of rotation on surface potential.

Mineral composition influences surface charging sensitivity, with plagioclase being most sensitive.

Abstract

Surface charging phenomenon of asteroids, mainly resulting from solar wind plasma and solar radiation, has been studied extensively. However, the influence of asteroid's rotation on surface charging has yet to be fully understood. Here neural network is established to replace numerical integration, improving the efficiency of dynamic three-dimensional simulation. We implement simulation of rotating asteroids and surrounding plasma environment under different conditions, including quiet solar wind and solar storms, various minerals on asteroid's surface also be considered. For asteroids with rotation periods comparable to orbital period, effect of orbital motion and obliquity also be studied. Results show that under typical solar wind, the maximum and minimum potential of asteroids will gradually decrease with their increasing periods, especially when solar wind is obliquely incident. For asteroid has period longer than one week, this decreasing trend will become extremely slow. During solar storm passing, solar wind plasma changes sharply, the susceptibility of asteroid's surface potential to rotation is greatly pronounced. Minerals on surface also count, plagioclase is the most sensitive mineral among those we explored, while ilmenite seems indifferent to changes in rotation periods. Understanding the surface charging of asteroid under various rotation periods or angles, is crucial for further research into solar wind plasma and asteroid's surface dust motion, providing a reference for safe landing exploration of asteroids.