A Study of Heliospheric Modulation of Galactic Cosmic Rays

Abstract:

We present results of the nature of heliospheric modulation of galactic cosmic rays during quiet conditions and all days of the month. In particular, the effect of heliospheric magnetic field on the mean and amplitudes of the diurnal flux of the galactic cosmic ray from 1999- 2015 have been investigated. The features (mean and amplitude) of the diurnal wave of cosmic ray flux from four neutron monitor stations (Inuvik, Moscow, Oulu and Rome) in the Mid and high latitude where obtained from the discrete Fourier transformation (DFT). Cross correlation analysis reveal a strong correlation > 0.73 with a time lag of 12-15 months for the sunsport number, while the interplanetary magnetic field (IMF) parameter did not show any time lag. The number of coronal mass ejections (nCMEs) had a weak but significant correlation (~0.29) with the monthly mean of the diurnal flux with a time lag of 72 months, while the flow speed correlated better (~0.57) for all a station without a zero time lag. It is suggested that the short time features of the diurnal flux is driven more by the flow speed and the IMF while the longer term influence is associated with coronal mass ejections and sunspot number.