Auroral Charging at Low Earth Orbit

Abstract

Recently, abnormal solar activity (sunspot explosion) has resulted in high-energy solar winds, which disrupted Earth's magnetosphere and caused severe geomagnetic storms. Those storms originate from the tail part of Earth's magnetosphere and travel toward Earth as high-energy electron clouds, causing damage to Earth's communication networks and power grids, with auroras observed in polar regions. Satellite failures due to abnormal space weather conditions have occurred frequently in recent decades Abnormal solar winds induce geomagnetic storms and create high-energy plasma environments, impacting satellite systems operating in Earth orbit. Among many side effects of abnormal space weather conditions, spacecraft charging refers to the accumulation of charge on spacecraft, including satellites, resulting from interactions with space plasma. Excessive charge accumulation would lead to ESD on the spacecraft's surface, finally causing satellite damage and malfunctions. Therefore, it is essential to consider the charging effect in the design of satellites to ensure resilience against space weather changes. This study numerically investigates the spacecraft charging of a model satellite in a typical LEO plasma environment and the worst-case plasma environment encountered in auroral regions. The surface potentials and potential differences on the surface are emphasized to identify the position of ESD. The potential distribution around the satellite and electron and ion densities were also analyzed to understand charge accumulation and distribution. The results of this study are expected to aid in identifying ESD issues caused by spacecraft charging in LEO and in analyzing possible damage to satellite components, contributing to the development of more resilient satellite systems.