Variations of cosmic ray intensity with the solar flare index, coronal index, and geomagnetic indices: Wavelet and cross correlation approaches

Abstract

In this study, the cosmic ray stuff and its associations with the solar flare index, coronal index, and geomagnetic indices, such as Kp, auroral electrojets, Ap, disturbance storm time (Dst), polar cap, Lyman-alpha, Hp60, and Ap60 indices, were studied using wavelet-based approaches over KIEL and MOSC stations during 2003 and 2004. The cosmic ray data used in this study were obtained from ground-based neutron monitor stations. Different sources are also used to get data on the different indices used in this study. The yearly variation in cosmic ray intensity revealed that the intensity of cosmic rays over KIEL and MOSC stations was greater in 2004 and lower in 2003. This variation might be due to the ring current's asymmetry, which causes an enormous asymmetry in the storm-time cosmic-ray increase. The wavelet coherence transform shows a positive and negative correlation as well as cosmic ray lags with solar flares and coronal indices throughout different months of the 2003 and 2004 periods over both suggested stations. The results of cross correlation indicate that cosmic ray intensity is positively correlated with all geomagnetic indices. However, cosmic ray intensity was negatively associated with the Dst index during 2003 and 2004 over both suggested stations. Moreover, multi-resolution analysis and power spectral density (PSD) analysis are consistent with wavelet analysis. Using the PSD result, we have seen high-power wavelet regions during geomagnetically quiet months and low-power wavelets during disturbed months at a common frequency over both stations during 2003 and 2004.