Mercury in the solar wind: adaptive kinetic model for space weather at solar system's innermost planet

Introduction

We develop a new type of a global plasma simulation model with adaptive charged particle kinetic physics for the Mercury-solar wind interaction.

Unique Characteristics of Mercury

Mercury’s solar wind interaction, or space weather, is unique in the solar system due to several factors:

• Spatially small and temporally fast magnetospheric scales
• Airless solid body with a large conducting core
• Tenuous surface-originating exosphere
• The closest distance to the Sun of all the planets

These features mean that Mercury is an ideal "compact-sized magnetospheric solar wind interaction laboratory" for spacecraft and model studies compared to Earth's much larger magnetosphere.

Importance of Mercury's Plasma Environment

Since Mercury's plasma environment is populated by a unique composition of exospheric heavy ions mixed with the solar wind, the magnetosphere is much smaller than at Earth. Under stronger solar wind conditions, studying Mercury reveals new information on space weather processes in general.

Scientific Objectives of the BepiColombo Mission

The main scientific objectives of the BepiColombo (BC) two-orbiter mission en route to Mercury include:

1. Investigation of the structure and dynamics of the Hermean magnetosphere
2. Exploration of the Hermean exosphere

Development of the New Model

The new model to be developed in this project is based on high-performance computing and an adaptive algorithm for charged particle kinetic effects. This enables efficiently resolving Hermean space weather processes and the coupled, complex solar wind-magnetosphere-exosphere system in detail beyond current global models.

Application of the Model

The new model is applied in the interpretation of observations by BC, focusing on the role of charged particle effects in the physics of basic space weather processes.