Iskra K. Long-period and short-period variations of cosmic ray intensity and anisotropy based on the experimental data and the theoretical modelling

The thesis deals with the study of the long-period and short-period variations of cosmic ray (CR) intensity and anisotropy. The rigidity spectra of the 11-year variations of cosmic ray intensity have been obtained for long period of CR observations (1960-2002). It has been shown that the spectrum of CR intensity variation is relatively hard in the minimum epochs of the solar activity and the softes variation spectrum corresponds to the highest activity of the Sun. The power spectrum density (PSD) of the interplanetary magnetic field (IMF) turbulence has been obtained and it has been shown that the essential temporal rearrangements of the structure of turbulent heliospheric magnetic fields during solar activity cycle causes the changes of CR diffusion features. Based on the analyses of the numerical solution of the cosmic ray transport equation, and also on the study of CR experimental results, there has been obtained the linear relationship between the rigidity spectrum exponent of the GCR intensity variations and the exponent of the PSD of heliospheric magnetic field , which is realized independent on the sign of IMF polarity. The GCR anisotropy was investigated in sectors with different magnetic field polarity.