Rigidity dependences of the main characteristics of Forbush decreases

Abstract

Abstract Forbush decrease is an effect in the cosmic rays physics which manifests itself as a sudden depression of the intensity of cosmic rays. Active phase of Forbush decrease lasts for several days and is often accompanied by a geomagnetic storm. The reason for such sudden depressions originates from the Sun, and is connected with a phenomenon of solar physics known as coronal mass ejections. Nowadays Forbush decreases are mostly studied by ground based detectors such as neutron monitors and muon hodoscopes. These detectors are characterized by small statistical fluctuations but register secondary cosmic rays which are created in interactions of primary cosmic rays with Earth atmosphere. This work is based on the data obtained by the satellite experiment PAMELA. The main characteristics of Forbush decreases are calculated for a fluxes of cosmic rays protons in the rigidity range 0.8 – 9 GV.