Space weather at Mercury and more
Abstract: Mercury is the only planet in the inner solar system, other than Earth, that possesses a dynamo-generated global, albeit weak, magnetic field. As a consequence of this weak field and the planet's proximity to the Sun, the magnetosphere of Mercury is highly dynamic, especially during times of interplanetary coronal mass ejections (ICMEs). It has been long hypothesized that the magnetic flux on Mercury's dayside may be completely eroded or compressed below the surface during extreme conditions. In this talk I will present the first observations of an ICME compressing Mercury's dayside magnetosphere below the surface. This allows the ICME plasma to interact directly with Mercury's surface, weathering the regolith and sputtering particles into the exosphere. The collapse of Mercury's dayside magnetosphere has important implications for the habitability of close-in exoplanets around M dwarf stars, as such events may significantly contribute to planetary atmospheric loss in these systems. I will also briefly discuss future work on comparative space weather at different planets, as well as on ICME propagation, ICME-driven GCR modulation, and small flux rope evolution in the inner heliosphere.