On the role of the active-region latitudes in the processes of cosmic-ray modulation

Abstract

The time dependence of galactic cosmic rays is described using the solar activity indices η^αexp[−(ϕ/ϕ₀)^β] and η^α/(k + ϕ^β), where η and ϕ are the number of groups of sunspots and their heliolatitude. The data of measurements of fluxes of galactic cosmic rays in the maximum of the high-altitude run in the polar atmosphere (Murmansk) and the Climax neutron monitor data were used. Beginning with 1957, four periods between the inversions of the polar magnetic field of the Sun are considered, during which the field sign remained invariable for several years. For each of these periods, the values of α, β, ϕ₀, and k were determined by the least-squares method. The best description of the experimental data on cosmic rays was found by enumeration of the values of these parameters. The reported solar activity indices quite adequately describe the long-term modulation of galactic cosmic rays over the ∼50-year observation period.