We are interested in the global magnetospheric impact of large-scale solar events, such as coronal mass ejections, which can trigger intense magnetic storms.
In the absence of continuous monitoring, the geomagnetic activity of the magnetosphere is often estimated using magnetic indices such as DST, Kp or auroral indices. Calculated from the ground-based measurements of the magnetic field deviation, they provide an integrated view of the current circulation in space from the ionosphere to the boundaries of the magnetosphere.
We use simultaneous observations from several missions including Cluster, THEMIS and MMS in the magnetosphere and we examine how such in-situ observations could add extra information to qualify and quantify the geomagnetic activity of the magnetosphere. We estimate the magnetic flux content of the magnetosphere and discuss its evolution during the different phases of a magnetic storm during the impact of a coronal mass ejection. In particular, we evaluate its diurnal and nocturnal dynamics as well as the phases of conservation or loss of magnetic flux content.