Dynamical Complexity in Geomagnetically Induced Current Activity Indices Using Block Entropy

Geomagnetically Induced Currents (GICs) are a manifestation of space weather events at ground level. GICs have the potential to cause power failures in electric grids. The GIC index is a proxy of the ground geoelectric field, derived solely from geomagnetic field data. Information theory can be used to shed light on the dynamics of complex systems, such as the coupled solar wind-magnetosphere-ionosphere-ground system. We perform Block entropy analysis of the GIC activity indices at middle latitude European observatories around the St. Patrick’s Day March 2015 intense magnetic storm and Mother’s Day (or Gannon) May 2024 superintense storm. We find that the GIC indices values are generally higher for the May 2024 storm, indicating elevated risk levels. Furthermore, the entropy values of the SYM-H and GIC indices are higher in the time interval before the storms than during the storms, indicating the transition from a system with lower organization to a system with higher organization. The results show promise for space weather applications.