Is geomagnetic activity driven by solar wind turbulence?

The Earth's magnetosphere is a highly dynamical system, which continuously exchanges energy, mass and momentum with the solar wind and the Earth's ionosphere. Existing literature would suggest that particular large amplitude interplanetary Alfvén wave trains might cause intense auroral activities known as High‐Intensity Long‐Duration Continuous Auroral Activity (HILDCAAs), as a result of the magnetic reconnection between the southward magnetic field z component and the magnetopause magnetic fields. This paper presents a statistical analysis concerning the role played by Alfvénic turbulence in the solar wind‐magnetosphere coupling as a function of the solar cycle. We find that Alfvénic fluctuations are geoeffective at solar minimum while at solar maximum magnetic structures play a role.