Cosmic rays as an indicator of the geoeffectiveness of magnetic clouds

Abstract

Geomagnetic storms are initiated by organized magnetic structures of the solar wind. The intensity of magnetic storms is determined by the product of the southward component of the magnetic field and the time interval, during which the structure is located near Earth: the larger the product, the higher the storm intensity. To determine the local properties of the structures, direct spacecraft measurements of the plasma and magnetic field characteristics are used. Global properties of the structures are also of great interest. Such information can be obtained using measurements of cosmic rays by the worldwide network of neutron monitors. Magnetic clouds are examples of these structures. About 30% of magnetic storms are caused by magnetic clouds. In our theory of the formation of Forbush decrease in a magnetic cloud, it has been found that the components of the vector anisotropy in time are determined by the magnetic cloud type. Thus, using the cosmic ray method, it is possible to determine a connection between the magnetic cloud type and the intensity of the magnetic storm. Similar connections can be made for other magnetic structures.