Solar Wind, IMF Bz, and Geomagnetic Storm Coupling as Precursors to Forbush Decrease Events in Solar Cycle 25

Forbush Decrease (FD) events are sudden decreases in galactic cosmic ray intensity caused by interplanetary disturbances such as coronal mass ejections (CMEs), solar wind shocks, and strengthened magnetic fields. This study looks at the relationship between solar wind characteristics, the Interplanetary Magnetic Field (IMF B and Bz), and geomagnetic storm indices (Dst and Kp) as antecedents of Forbush Decrease events during Solar Cycle 25 (2023-2026). The study found robust associations between sustained southward IMF Bz, high solar wind velocity (>600 km/s), and powerful geomagnetic storms (Dst < −200 nT), which are known to precede large FD events.The findings confirm that solar wind disturbances and geomagnetic storm intensity act as reliable precursors for Forbush Decrease forecasting and contribute to improved space weather prediction models during Solar Cycle 25.