Influence of high-speed streams from coronal holes on cosmic ray intensity in 2007

Abstract

The effect of high-speed solar wind streams from low-latitude coronal holes on cosmic ray intensity is studied. The database on Forbush effects created at IZMIRAN, with cosmic ray density and anisotropy calculated by the Global Survey Method (GSM) on the basis of Neutron Monitor network data has been used for the entire 2007. From the analysis of events in 2007 it was found that relationship of the Forbush effect magnitude to the solar wind speed is much weaker than to the magnitude of the interplanetary magnetic field. Best of all the FE magnitude correlates with a 'critical' rigidity of the CR determined by the magnetic shield created by interaction of the high speed streams from coronal holes with low speed solar wind.