Dynamical Complexity in Geomagnetically Induced Current Activity Indices Using Block Entropy.

Area of Science:

• Space Physics
• Geophysics
• Information Theory

Background:

• Geomagnetically Induced Currents (GICs) are ground-level effects of space weather, posing risks to electric power grids.
• The GIC index, derived from geomagnetic data, serves as a proxy for the ground geoelectric field.
• Information theory offers tools to analyze complex coupled systems like the solar wind-magnetosphere-ionosphere-ground system.

Purpose of the Study:

• To apply block entropy analysis to GIC activity indices.
• To investigate the dynamics of GIC and geomagnetic indices during major space weather events.
• To assess the potential of entropy analysis for space weather forecasting and risk assessment.

Main Methods:

• Block entropy analysis was performed on GIC activity indices.
• Data from middle-latitude European observatories were analyzed.
• The analysis focused on the March 2015 St. Patrick's Day storm and the May 2024 Mother's Day storm.

Main Results:

• GIC index values were higher during the May 2024 storm, indicating increased risk.
• Entropy values for GIC and SYM-H indices were higher before storms than during storms.
• This suggests a transition from lower to higher system organization preceding and during geomagnetic storms.

Conclusions:

• Entropy analysis of GIC indices can reveal pre-storm susceptibility.
• The findings highlight the potential for improved space weather forecasting.
• This research contributes to understanding geomagnetic disturbances and their geospatial risks.