Cosmic rays and solar wind turbulence: Peculiarities of the 23rd solar cycle

Abstract

This paper addresses observed variations in cosmic ray (CR) intensity, the interplanetary magnetic field (IMF), the solar wind (SW) turbulence energy spectrum, and the energy spectrum index of Forbush decreases in the 20th–23rd solar cycles. Unlike the previous three cycles, there are some distinctive features in the 23rd solar cycle. The entire cycle shows a considerable increase in the index of the SW turbulence energy spectrum inclination and an substantially harder energy spectrum of Forbush decreases. The anomalously high flux of high-energy CRs and the anomalously low level of the IMF strength were recorded at the end of this cycle. The conclusion has been made that such unusual CR behavior is associated with a decrease in the degree of scattering in the resonance interaction between CR fluxes and SW inhomogeneities with spatial scales of ∼1012 cm.