Peculiarities of sporadic variations in density and anisotropy of galactic cosmic rays in solar cycle 24

Abstract

In this work, we have processed data from the global network of neutron monitors and muon telescopes by the global survey method to study variations in the density and anisotropy of galactic cosmic rays during Forbush decreases observed in solar cycle 24. The simultaneous use of two different type detectors made it possible to examine the temporal dynamics of the angular distribution of cosmic rays in two different energy intervals. Besides, we have used measurements of the Yakutsk cosmic ray spectrograph after A.I. Kuzmin to assess the energy spectrum index during large disturbances of the interplanetary medium in this cycle. Analysis of the results obtained confirms our early statements that solar activity cycle 24 features an increased level of turbulence in the interplanetary magnetic field.

Large-amplitude Bidirectional Anisotropy of Cosmic-Ray Intensity Observed with Worldwide Networks of Ground-based Neutron Monitors and Muon Detectors in 2021 November

“…The rigidity dependence of the FD has been analyzed by using NM and MD data in many studies, and it is well known that the density depression in FD decreases with increasing rigidity (Suda & Wada 1979;Nishida 1983;Sakakibara et al 1985;Grigoryev et al 2022). This is consistent with γ 0 in Figure 3(d) (black curve) staying between −1.5 and −1.0 when significant depressions of the density ( ( ) x t c 0,0 ) are observed.…”