Abstract:

Galactic Cosmic Rays (GCRs) are highly energetic particles originating from outside the solar system, whose intensity is modulated by solar wind conditions and the Interplanetary Magnetic Field (IMF). This study investigates the relationship between solar wind parameters and Cosmic Ray Intensity (CRI) variations during solar cycle 25 (2019-2025). Using multi-parameter datasets from neutron monitor networks and spacecraft observations (ACE/DSCOVR), we perform statistical correlation and regression analysis between CRI, solar wind speed, IMF magnitude, proton density, and geomagnetic indices (Dst and Kp). The results reveal a strong inverse correlation between CRI and IMF magnitude (r ≈ -0.72) and a moderate inverse correlation with solar wind speed (r ≈ -0.65). Significant Forbush Decreases (FDs) are observed when solar wind speed exceeds ~600 km/s, and IMF strength surpasses ~15 nT, resulting in CRI reductions of 3-8% on average, with peak events reaching >10% suppression. Additionally, CRI variations show a moderate correlation with geomagnetic activity (Kp: r ≈-0.58; Dst: r ≈ +0.60), indicating coupled but distinct physical processes. The findings confirm that solar wind kinematics and magnetic field enhancements are the dominant drivers of short-term cosmic ray modulation, providing important insights for space weather forecasting and heliospheric dynamics.

Keywords:

Galactic Cosmic Rays (GCRs), Forbush Decreases (FDs), Solar Wind Parameters, Interplanetary Magnetic Field (IMF), Space Weather Forecasting

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