Impact of Interplanetary Parameters on Cosmic Rays 27-Day Variation

The observed modulation of galactic cosmic ray intensity on time and spatial scales contains information regarding their transport in the heliosphere. We used the data of cosmic ray neutron monitor as well as interplanetary parameters to identify the correlation between their 27-day variations. The 27-day variation of cosmic ray intensity is found to linearly correlated with the interplanetary magnetic field strength (B), the north south component (Bz) of the interplanetary magnetic field vector and the product of the solar wind speed (V) times B (V x B). The cross correlation function of the 27-day cosmic ray variation versus the solar wind speed shows a negative correlation. However, the 27-day variation of cosmic rays is correlated with the variation in both the x- and y- components of interplanetary magnetic field.