Effect of Geomagnetic Storms on Space Weather during the Ascending Phase of Solar Cycle 24

Abstract

Space weather disturbances are significantly influenced by geomagnetic storms, which arise from intensified solar wind-magnetosphere coupling. This study examines the correlative dynamics of solar activity indicators (Sunspot Number, F10.7 index), interplanetary parameters (solar wind plasma speed, IMF scalar B), and planetary geomagnetic activity (Dst, Ap, auroral electrojet indices) during this extraordinary space weather regime. A statistical methodology based on correlation analysis and linear regression techniques is employed using multi-source observational datasets (e.g., OMNI database and geomagnetic indices) to quantify relationships among these parameters. The analysis reveals a profound disassociation between solar activity eruption rate and terrestrial storm intensity. Even though solar activity indicators, like sunspot numbers, showed strong increases in solar activity towards solar maximum, equatorial ring current activity (Dst index) was notable for its lack of strong excursions (Dst ≤ -100 nT). This is attributed to the extraordinary expansion of Coronal Mass Ejections (CMEs) in the low-pressure solar wind, leading to a dilution of internal magnetic flux. The study concludes that geomagnetic activity was dominated by the kinematic energy of moderate-speed solar wind streams, as opposed to solar magnetic flux emergence. The kinematic energy of solar wind streams was responsible for sustaining localized high-latitude auroral substorms throughout this extraordinary space weather regime. The equatorial magnetic field was found to be undisturbed.