Global Effect of Long‐Lasting 07–12 October 2024 Geomagnetic Storms During the Transition From a Strong (G3) to a Severe (G4) on the Geomagnetic Field and Ionospheric Parameters Distribution

Abstract

This study investigates the co‐evolution of geomagnetic field disturbances with ionospheric parameters and their characteristic latitudinal signatures by conducting a location and time‐dependent analysis of the 07–12 October 2024 events, to fill crucial gaps in understanding the coupled response of the magnetosphere‐ionosphere system. This has been carried out utilizing integrated multi‐instrument approach combining ground‐based magnetometer‐derived geomagnetic fields deviations from the mean (ΔBx, ΔBy, ΔBz), Digisonde‐derived critical frequency and maximum electron density at the F2‐ionospheric layer (foF2, hmF2), and Global Navigation Satellite System Total Electron Content (GNSS TEC) measurements. Significant disturbances in the ΔBx component are observed across all sectors in the low‐latitude region, particularly when the storm intensity increases; while in the mid‐latitude region, all magnetic field components exhibit significant disturbances across American stations. Mid‐ and low‐latitude stations displayed more stable but still disturbed patterns in both storm cases, with phase dependent and sector‐specific ionospheric responses. During the initial phase, prompt penetration electric fields increased TEC in low‐latitude regions, particularly during evening hours (19:00–23:00 UT) when the equatorial ionization anomaly was strongest. The American sector experienced the most pronounced and coincide geomagnetic field and ionospheric perturbations during both storms, showing the largest ΔBx and TEC enhancements relative to quiet‐time maxima. Notably, the main phase of the 10–12 October 2024 storm resulted in the largest depletion of TEC and foF2, measured against quiet‐time minima. Larger TEC enhancements also coincides with substantial hmF2 depression and foF2 reduction than higher hmF2 and foF2 when the intensity of the storm enhances.