Galactic Cosmic Ray Modulation Up to Recent Solar Cycles

Abstract

Galactic Cosmic Ray Modulation Up to Recent Solar Cycles Cosmic ray neutron monitor counts obtained by different ground-based detectors have been used to study the galactic cosmic ray modulation during the last four solar activity cycles. Since long, systematic correlative studies have been per-formed to establish a significant relationship between the cosmic ray intensity and different helio-spheric activity parameters, and the study is extended to a recent solar cycle (23). In the present work, the yearly average of 10.7 cm solar radio flux and the interplanetary magnetic field strength (IMF, B) have been used to find correlation of the yearly average cosmic ray intensity derived from different neutron monitors. It is found that for four solar cycles (20-23) the cosmic ray intensity is anti-correlated with the 10.7 cm solar radio flux and the IMF, B value with some discrepancy. However, this is in a good positive correlation with the flux of mentioned wavelength for four different solar cycles. The IMF, B shows a weak correlation with cosmic rays for solar cycle 20, and a good anti-correlation for solar cycles 21-23.