Features of the 11-year variation of galactic cosmic rays in different periods of solar magnetic cycles

Variations of galactic cosmic ray intensity have been studied based on the neutron monitors and interplanetary magnetic field experimental data for different ascending and descending epochs of solar activity. The dependence of the diffusion coefficient on the cosmic ray particles rigidity R is stronger in the maxima epoch than in the minima epoch of solar activity. For the period of 1977-1981 (qA > 0) the diffusion coefficient for the minimum epoch is, χmin ∝ R0.7 ± 0.04 and for the maximum χmax ∝ R1.3 ± 0.05; for the period of 1987-1990 (qA < 0), χmin ∝ R0.8 ± 0.05 and χmax ∝ R1.1 ± 0.04. The exponents νy and νz of the power spectral density of the By and Bz components of the IMF in the region of the frequencies (10−6- 4 × 10−6) Hz are larger for the minimum epoch of 1987 (νy ≈ 2.0 and νz ≈ 1.93) than for the maximum epoch of 1990 (νy ≈ 1.43 and νz ≈ 1.27).