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

## TL;DR

This study employs a novel ten-moment multifluid model to simulate Mercury's interior-magnetosphere system, capturing collisionless magnetic reconnection and magnetospheric dynamics with good agreement to observations.

## Contribution

It introduces the first 3D ten-moment multifluid simulation of Mercury's coupled interior and magnetosphere, including non-ideal effects critical for collisionless reconnection.

## Key findings

- Reproduces observed magnetic field vectors and current sheet asymmetry.
- Shows Mercury's magnetosphere responds dynamically to extreme solar wind conditions.
- Plasmoids form in the magnetotail during high-pressure events.

## Abstract

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 non-ideal effects including the Hall effect, 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 the MHD approach) and the simulation results are in good agreement with spacecraft observations. We also study the magnetospheric response of Mercury to a hypothetical 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.