On the Effects of the Solar Wind Structure in the Global Distribution of dBH/dt Spikes During Geomagnetic Storms

Abstract Variations in the solar wind, particularly those associated with interplanetary coronal mass ejections (ICMEs) and high‐speed streams (HSSs), drive geomagnetic disturbances that produce rapid changes in the ground magnetic field. These variations, commonly quantified by the time derivative of the horizontal magnetic field , are closely related to geomagnetically induced currents (GICs), which pose risks to technological infrastructure. In this study, we analyze 609 geomagnetic storms (SYM‐H nT) from 1995 to 2024, interplanetary coronal mass ejection and HSS driven events, to investigate how different solar wind drivers modulate the occurrence, intensity, and spatiotemporal distribution of spikes. We find that enhancements are concentrated between 60 and 75 magnetic latitude for both drivers, but exhibit distinct Magnetic Local Time (MLT) distributions. HSS‐driven storms predominantly produce pre‐midnight enhancements, consistent with substorm‐related processes, whereas ICME‐driven storms generate a broader MLT distribution, including significant post‐midnight activity associated with multiple current systems, such as the substorm current wedge and field‐aligned currents. Additionally, we show that the occurrence and intensity of spikes vary systematically with the solar cycle, with ICME‐driven activity peaking during solar maxima and HSS‐driven activity dominating the declining and minimum phases. These results provide a unified long‐term perspective on how solar wind drivers control rapid geomagnetic field variations, highlighting the importance of distinguishing between driver types for improving space weather modeling and GIC risk assessment.