Numerical Simulation of Cosmic Rays Modulation in Coratating Interaction Regions

Shock pairs associated with Coratating Interaction Regions (CIRs) in the solar wind are believed to play an important role in the transport of galactic cosmic ray (GCR) particles. In this invesitation, we carry out three-dimensional simulations of GCR modulation by CIRs. The CIR structure is computed with a time-dependent global MHD simulation code. Based on this plasma background, we calculate the corresponding diffusion parameters in the CIRs region. Subsequently, we investigate cosmic ray transport using the Parker transport equation. The latter is numerically solved using an Alternative Direction Implicit scheme. We compute the global distribution of GCRs and explore the correlations between the characteristics of CIRs and the rate of decrease of GCR intensity obtained from observations.