Cosmic-ray vector anisotropy and local characteristics of the interplanetary medium

Abstract

Variations in the cosmic-ray vector anisotropy observed on Earth are closely connected with the state of the near-Earth interplanetary medium. Hourly characteristics of vector anisotropy for the period 1957–2013, which were obtained by the global survey method from the data of the worldwide network of neutron monitors, make it possible to study the relationship between the cosmic-ray anisotropy and solar wind parameters. In the present work, we have studied the connection between the equatorial component of anisotropy of cosmic rays with a rigidity of 10 GV and the following parameters: velocity and density of the solar wind; density of the interplanetary magnetic field; and cosmic-ray density variations, in which the spatial gradient of cosmic rays in the interplanetary medium is manifested. The characteristics of cosmic-ray anisotropy at various combinations of the interplanetary medium parameters are compared. The possibility of diagnosing the solar wind state from data on the cosmic-ray anisotropy is discussed.