The magnetospheric response to the solar wind is nonlinear. Information theoretical tools are able to characterize the nonlinearities in the system. We show that nonlinear significance of D_st peaks at lags of 3–12 hours which can be attributed to VB_s, which also exhibits similar behavior. However, the nonlinear significance that peaks at lags of 25, 50, and 90 hours can be attributed to internal dynamics, which may be related to the relaxation of the ring current.

ESA's constellation mission Swarm makes it possible for the first time to determine field-aligned currents (FACs) reliably in the ionosphere. FACs are able to transport energy from the solar wind to the Earth and heat the upper atmosphere. Here we investigate FAC structures that have been missed by previous satellite missions. Most of them are found poleward of the northern light zone. The energy sources seem to be located on the nightside of Earth about 100 000 km away.

Rapid fluctuations in amplitude and phase of radio waves passing through the ionosphere degrade GPS positional accuracy and can lead to navigational errors, particularly during geomagnetic storms. As a function of magnetic latitude and local time, regions of GPS phase scintillation at high latitudes are identified in the context of coupling between the solar wind and the magnetosphere-ionosphere system, which primarily depends on the interplanetary magnetic field magnitude and orientation.

A series of interplanetary coronal mass ejections in the period 7–17 March 2012 caused geomagnetic storms that strongly affected the high-latitude ionosphere in the Northern and Southern Hemisphere. Interhemispheric comparison of GPS phase scintillation reveals commonalities as well as asymmetries, as a consequence of the coupling between the solar wind and magnetosphere. The interhemispheric asymmetries are primarily caused by the dawn-dusk component of the interplanetary magnetic field.