Quantifying the Importance of Upstream Magnetic Field Fluctuations for Solar Wind-Magnetosphere Coupling

Solar wind drives magnetospheric dynamics through coupling with the geospace system at the magnetopause. While upstream fluctuations correlate with geomagnetic activity, their impact on the magnetopause energy transfer is an open question. We examine three-dimensional global simulations using the Geospace configuration of the Space Weather Modeling Framework to study the effects of solar wind fluctuations during a substorm event. We demonstrate that upstream fluctuations intensify the energy exchange at the magnetopause increasing both energy flux into and out of the system. The increased energy input is reflected in ground indices. The fluctuations also regulate the energy transport within the magnetotail neutral sheet. We complement our numerical efforts by using a large statistical set of over 4,000 magnetopause crossings of the Magnetospheric Multiscale mission to resolve the local energy exchange at the low-latitude dayside magnetopause. We aim at revealing how the interplay between the current state of the system and external drivers reflects to the boundary dynamics. As the exchanged energy fundamentally determines how the solar wind drives magnetospheric activity, it is important to understand where and under which local and global conditions the most significant energy transfer rates occurs.