Global Ten-Moment Multifluid Simulations of the Solar Wind Interaction with Mercury: From the Planetary Conducting Core to the Dynamic Magnetosphere

For the first time, we explore the tightly coupled interior‐magnetosphere system of Mercury by employing a three‐dimensional ten‐moment multifluid model. This novel fluid model incorporates the nonideal effects including the Hall effect, electron inertia, and tensorial pressures that are critical for collisionless magnetic reconnection; therefore, it is particularly well suited for investigating collisionless magnetic reconnection in Mercury's magnetotail and at the planet's magnetopause. The model is able to reproduce the observed magnetic field vectors, field‐aligned currents, and cross‐tail current sheet asymmetry (beyond magnetohydrodynamic approach), and the simulation results are in good agreement with spacecraft observations. We also study the magnetospheric response of Mercury to an extreme event with an enhanced solar wind dynamic pressure, which demonstrates the significance of induction effects resulting from the electromagnetically coupled interior. More interestingly, plasmoids (or flux ropes) are formed in Mercury's magnetotail during the event, indicating the highly dynamic nature of Mercury's magnetosphere. This novel ten‐moment multifluid model represents a crucial step toward establishing a revolutionary approach that enables the investigation of Mercury's tightly coupled interior‐magnetosphere system beyond the traditional fluid model and has the potential to enhance the science returns of both the MESSENGER mission and the BepiColombo mission.