Unique Global Viewing of Earth’s Dynamic Magnetosphere with the Solar Wind – Magnetosphere – Ionosphere Link Explorer (SMILE)

The interaction between the plasma leaving the Sun and neutral particles in the exospheres of solar system bodies results in a soft X-ray emission which, if imaged, can help us to understand these interactions of the solar wind with these bodies on large scales. At magnetized bodies, the impact of the solar wind results in global deformations of planetary magnetic fields and physical processes at kinetic, fluid and global scales that capture and energise particles within magnetospheres which ultimately deposits energy into planetary ionospheres and atmospheres. While in-situ measurements have provided deep insights into small-scale processes in these regions, the global configuration of the system remains elusive, revealed only through simulation or climatological empirical models. A new joint mission between the European Space Agency (ESA) and Chinese Academy of Sciences (CAS) will provide a unique global view of our near-Earth space environment, enabling us understand the links between the Sun, magnetosphere and ionosphere. Due for launch in late 2025, the SMILE (Solar wind Magnetosphere Ionosphere Link Explorer) mission is a novel endeavour to observe the coupling of the solar wind with the magnetosphere through to the ionosphere. To do this, SMILE will remotely sense the magnetosheath and cusps through X-ray emissions from solar wind charge exchange – a process by which neutral particles in Earth’s exosphere exchange charges with highly charged heavy solar wind ions. SMILE is a self-standing mission, that takes its own in situ measurements of the solar wind and magnetosheath plasma and magnetic field input into the magnetosphere, as well as crucial far ultraviolet observations of the entire northern hemisphere auroral oval to explore the link between the solar wind, magnetosphere and ionosphere. In this talk, we will present the underlying science of the SMILE mission as well as the latest mission developments from ESA, CAS and the international instrument teams. We will also highlight possible synergies with existing missions and ground-based facilities, enabling global and local plasma processes to be studied in unprecedented detail and context.