Relationship between cosmic ray intensity and Earth's magnetic field: Cross-wavelet analysis during intense and moderate geomagnetic storms

This study investigated the relationship between the cosmic ray intensity (CRI) and the horizontal component of Earth's magnetic field (dH) during two intense geomagnetic storms that occurred on September 8, 2017, and August 26, 2018, and a moderate storm on February 18, 2020 over three stations: IRKT, YKTK, and HRMS. The findings of this study indicate that the CRI and dH do not exhibit a simple association over each station. A significant decrease in CRI and dH was seen during the intense geomagnetic storm on September 8, 2017, over all stations as compared to the other two storm events. The decrease was more pronounced over the YKTK station, which has low cutoff rigidity (1.65 GV), than the HRMS (4.58 GV) and IRKT (3.64 GV) stations with high cutoff rigidity. Furthermore, the cross-wavelet analysis reveals that the relationship between CRI and dH varies with the strength of the storm, the location, and the cutoff rigidity of the station.