Turbulence state of the interplanetary magnetic field during the 27 27- days wave of the galactic cosmic rays in different epochs of solar activity

摘要

Studies of the 27 27-days variation of the galactic cosmic rays (GCR) intensity lead to a statement of itˇs sin sinu- usoidal charac soidal character (if we take into account only one solar rotation period). Thus, the natural occurs division of this wave ter into two parts - the first 'decreasing' and the second 'increasing'. We examine both parts separately fin finding the power ing spectral density (PSD) of t the interplanetary magnetic field (IMF) components defined as: PSD ∞fw, where f is frequency. We find that for the first part of the wave of the 27 quency. 27-days variation of the GCR intensity the power law spe spec- ctrum exponents of the components of IMF are larger trum larger- vx～0.98, vy～0.81, vz～0.68, than in the second part part-vx～0.73, vy～0.49, vz～0.51. Thus, the turbulence state of the solar wind is fairly different in those two fractions of the 27-days wave. This statement has a few consequences, e.g. there is expected a hard rigidity spectrum in the first part of the 27-days wave and soft in the second.