This paper presents a comprehensive analysis of the solar event that occurred on 25 August 2018. This kind of comprehensive analysis plays a key role in better understanding the complexity of the processes occurring in the Sun–Earth system determining the geoeffectiveness of manifestations of solar activity. The analysis presented here shows for the first time a direct link between characteristics of solar perturbation, the magnetosphere–ionosphere system response and space weather effects.

We investigate the time variation of the magnetospheric and Earth's magnetic field during both quiet and disturbed periods. We identify the timescale variations associated with different magnetospheric current systems, solar-wind–magnetosphere high-frequency interactions, ionospheric processes, and internal dynamics of the magnetosphere. In addition, we propose a new local index for the identification of the intensity of a geomagnetic storm on the ground.