The Solar Wind – Magnetosphere Energy Coupling Function and Open Magnetic Flux Estimation: Two Science Aspects of the SMILE Mission

Abstract:

The Solar wind Magnetosphere Ionosphere Link Explorer (SMILE) is a novel self-standing mission to observe solar wind - magnetosphere coupling via simultaneous in situ solar wind /magnetosheath plasma and magnetic field measurements, X-ray images of the magnetosphere, and UV images of global auroral distribution defining system – level consequences. The SMILE mission is jointly supported by ESA and CSA, and the launch date is expected to be in 2021.

SMILE will address several key outstanding questions concerning how the solar wind interacts with the magnetospheres on a global level. Quantitatively estimating the energy input from the solar wind into the magnetosphere on a global scale is still an observational challenge. Using global MHD simulations, we derive a new solar wind – magnetosphere energy coupling function. The X-ray images of the magnetosphere from the SMILE mission will help estimate the energy transfer from the solar wind into the magnetosphere. A second aspect SMILE can address is the open magnetic flux, which is closely related to magnetic reconnections in the dayside magnetopause and magnetotail. In a similar way, we find that the open magnetic flux can be estimated through a combined parameter f, which is a function of the solar wind velocity, number density, the southern interplanetary magnetic field strength, and the ionospheric Pederson conductance. The UV auroral images from SMILE will be used to determine the open magnetic flux, which may serve as a key space weather forecast element in the future.