Speaker
Description
Using data from the AMS-02 instrument aboard the International Space Station, we examined long- term variations of the galactic cosmic ray (GCR) proton fluxes. This dataset enables a high-resolution study of time profiles and rigidity dependence within a rigidity range of 1 to 100 GV. We investigated the amplitude of long-term GCR variations using a power-law fit across the solar cycle. To understand the underlying physics, we correlated GCR variations with heliospheric magnetic field (HMF) turbulence, specifically analyzing power spectral density frequency exponents. During the studied period, the spectral index of the power-law rigidity spectrum exhibited clear solar cycle variability. Notably, the index tended to be higher during the solar maximum than during the solar minimum. The study provides evidence of an energy-dependent rigidity spectrum for long-term GCR variations: we observed a soft rigidity spectrum of GCR intensity variations for solar maximum and during the minimum a hard rigidity spectrum. These shifts are attributed to significant temporal rearrangements in the HMF turbulence structure between solar activity maximum and minimum. Moreover, AMS-02 data indicates a progressive softening of the spectra toward higher energy levels.