Study of anisotropic variation of cosmic rays intensity with solar activity

摘要

The annual average values of amplitudes and phases of first two harmonics of cosmic ray anisotropy have been derived by using the harmonic analysis technique for the period 1989 to 2004, which covers mostly the major period of solar cycles 22 and 23. In this paper we have taken the pressure corrected hourly data for Kiel neutron monitor station (cut off rigidity ≈ 2.29 GV) to derive the harmonic component of cosmic ray daily variation and compared with the data of Halekala neutron monitor (cut off rigidity ≈ 13.2 GV) for the period 1991 to 2004. From the analysis it has been concluded that the diurnal amplitude and phase of daily variation of cosmic rays have been found to be correlated with solar activity. However, the semi-diurnal amplitude and phase are inversely correlated with solar activity for both the stations.