As the Sun approaches the peak of its activity cycle, it creates the opportunity for more frequent and intense geomagnetic storms to affect Earth. This was clearly observed in early spring of 2023 when the Sun released several eruptive events. A recent geomagnetic storm in May 2024 served as another powerful reminder that the Sun’s state directly influences conditions on Earth, leading to increased fluctuations in our planet’s magnetic field. Consequently, auroras and other manifestations of solar activity were seen even at mid-latitudes. In this work, we focus on the Halloween storm of 2003 and the May storm of 2024, the two strongest geomagnetic events in the last three Solar Cycles. We perform a systematic comparison of the state of the Sun prior to the storms, focusing on solar flares and Halo coronal mass ejections. A comparative analysis of solar wind parameters and geomagnetic field responses is conducted to describe the strength of individual events and to reveal similarities and differences between the two storms. To characterize geoeffectiveness during the considered periods thoroughly, the geomagnetically induced currents indices are discussed based on data for latitudes between 58^ and 70^ in the European region.
Wawrzaszek et al. (Wed,) studied this question.