Magnetosphere-Interior Coupling at Mercury During Extreme Solar Events

Mercury is a fundamentally unique object in the solar system.

It possesses a weak global magnetic field of internal origin, and in consequence, a small magnetosphere, much smaller than the magnetosphere of Earth.

Due to the proximity of Mercury to the Sun, the magnetosphere of Mercury is subject to the most intense solar wind flux and ferocious space weather among all the planets in the solar system.

Moreover, Mercury has a large electrically conducting iron-rich core that occupies a much higher fraction of the planet’s mass and volume than do the cores of other planets in our solar system.

Therefore, electromagnetic (EM) induction effects in the planetary interior play a more prominent role in the small magnetosphere of Mercury compared to any of its companions.

The dynamics of the Hermean magnetosphere are highly driven by kinetic processes (e.g., very high magnetic reconnection rate) and are tightly coupled to its surface and interior, vulnerable to extreme solar events (e.g., Coronal Mass Ejection, CME).Due to the complex and non-linear nature of this coupling, the effects of the conductive interior and/or the kinetic aspects of the solar wind interaction with the small magnetosphere of Mercury have typically been neglected or simplified in previous analyses.

The goals of this project are to provide a comprehensive understanding of the complex magnetosphere-interior coupling at Mercury, and to explore the dynamics of this coupled system during extreme solar events.

We propose a three-year research program that will accomplish our objectives via an already developed hybrid-kinetic plasma model that self-consistently couples, for the firs time, the time-dependent inductive interior response with the external electromagnetic and kinetic plasma environment of Mercury.

We will compare our simulation results with previous NASA’s MESSENGER observations and with future observations by ESA/JAXA´s BepiColombo mission to Mercury. During the timespan of this project, BepiColombo is going to complete all of it six Mercury flybys.