Vector anisotropy of cosmic rays in the beginning of Forbush effects

Abstract

We consider the behavior of anisotropy and density of galactic cosmic rays in the first hours of Forbush effects from 1957 to 2014 initiated by the arrival of a shock wave. It has been shown that, as early as the event commencement, the first harmonic of anisotropy tends to increase substantially and its direction changes significantly. The more is powerful the interplanetary disturbance, the greater are the changes. Based on changes in some parameters of anisotropy and density, we can estimate the heliolongitude of the disturbance source, as well as the further development of the Forbush effect and geomagnetic activity.