http://arxiv.org/abs/2104.11279
We study features of the 3D anisotropy of galactic cosmic rays (GCR) for 1965-2014. We analyze the 27-day variations of the 2D GCR anisotropy in the ecliptic plane, and the north-south anisotropy normal to the ecliptic plane. We study the dependence of the 27-day variation of the 3D GCR anisotropy on the solar cycle and solar magnetic cycle. We demonstrate that the 27-day variations of the GCR intensity and anisotropy can be used as an important tool to study solar wind, solar activity and heliosphere. We use the components of the 3D GCR anisotropy found based on hourly data of neutron monitors (NMs) and muon telescopes (MTs) using the harmonic analyses and spectrographic methods. We correct 2D diurnal variation of the GCR intensity for the influence of the Earth magnetic field. We derive the north-south component of the GCR anisotropy based on the GG index calculated as the difference in GCR intensities of Nagoya multidirectional MTs. We show that behavior of the 27-variation of the 3D anisotropy verifies an existence of a stable long-lived active heliolongitudes on the sun. This finding illustrates usefulness of the 27-day variation of the GCR anisotropy as a unique proxy to study solar wind, solar activity and heliosphere. We distinguish a tendency of the 22-year changes of the amplitudes of the 27-day variation of the 2D anisotropy connected with the solar magnetic cycle. We demonstrate that the amplitudes of the 27-day variation of the north-south component of the anisotropy vary upon the 11 year solar cycle, however, a dependence of the solar magnetic polarity hardly can be recognized. We show that the 27-day recurrences of the $GG$ index and At component are in a high positive correlation, and both are highly correlated with By component of the heliospheric magnetic field.
R. Modzelewska and M. Alania
Mon, 26 Apr 21
32/45
Comments: 7 pages, 10 figures