Abstract | An electric current is driven on the magnetopause boundary of Mercury by interactions between the dayside Hermean magnetosphere and the solar wind with the embedded interplanetary magnetic field (IMF). Electromagnetic induction processes, due to external solar wind forcing resulting in magnetopause motion or magnetopause current structure changes, have been proposed as methods to determine the interior structure of Mercury. We developed a physics-based model of the Hermean magnetopause current system and its resulting magnetic field and used it to assess the impact solar wind forcing has on the magnetopause’s inducing field. The model was successfully compared to previous modelling work and observations from the MESSENGER mission. Using synthetic transient solar wind events and real solar wind conditions observed by Helios 1 and 2 as inputs to the model, we determined that the response of the magnetopause current structure and its resulting inducing field was impacted more by IMF variability than changes in the solar wind dynamic pressure. Helios data suggests solar wind conditions are highly unpredictable and there is a broad range of frequency signals in the solar wind that could be used to probe to different depths within the planet. In future, we hope to further validate this model against in situ measurements of Earth’s magnetosphere. The BepiColombo mission’s arrival at Mercury in 2025 will allow the response of the magnetopause’s system to external solar wind forcing to be further explored as a method of determining Mercury’s interior structure. |
