Solar Activity, IMF Bz, and Geomagnetic Storm Coupling During Solar Cycle 25 (2023–2026): Consequences for Forbush Decrease and Space Weather Prediction

Abstract Solar Cycle 25 has exhibited enhanced solar activity with increased sunspot numbers, elevated F10.7 solar flux, and frequent geomagnetic disturbances during its maximum and early declining phases (2023–2026). This study investigates the coupling between solar activity parameters (Sunspot Number and F10.7), interplanetary magnetic field (IMF B and Bz), solar wind speed, and geomagnetic indices (Dst and Kp) using a monthly dataset from January 2023 to January 2026. The analysis reveals a strong relationship between southward IMF Bz and geomagnetic storm intensity, with more negative Bz values corresponding to significant Dst depressions. Periods of high solar wind speed (>600 km/s) and enhanced IMF strength coincided with stronger geomagnetic storms and potential Forbush Decrease (FD) events. The results confirm that Solar Cycle 25 maximum (2023–2024) produced intense magnetospheric disturbances due to CME-driven solar wind structures.This study contributes to space weather forecasting by highlighting the predictive role of IMF Bz and solar wind parameters in geomagnetic storm and Forbush Decrease modeling. Keywords Solar Cycle 25; Sunspot Number; IMF Bz; Geomagnetic Storms; Dst Index; Solar Wind Speed; F10.7 Solar Flux; Forbush Decrease; Space Weather Prediction