Shock-induced diffuse aurora from electron scattering by chorus waves

Aurora, a natural light display in the Earth’s upper atmosphere, is produced by the interactions between downward-transiting electrons and atmospheric molecules. Like other geospace phenomena, aurora fundamentally depends on solar wind activity. However, directly testing this relationship has been challenging due to observational limitations. In this study, using observations from solar wind, the magnetosphere, the ionosphere, and the ground, we show that an interplanetary shock can trigger lower-band chorus waves in the magnetosphere. These waves subsequently drive magnetospheric electron precipitation and the diffuse aurora phenomenon. Our findings highlight diffuse aurora as a significant manifestation of the solar wind–magnetosphere–ionosphere coupling process.