Study of the solar magnetic field influence on the cosmic ray Sun shadow

Abstract

The cosmic rays originating outside the solar system are blocked by the Sun and form a shadow in the sky map. The Sun shadow is affected by the magnetic field between the Sun and the Earth. Therefore the Sun shadow can be used as a probe of the magnetic field and its intensity variations. In this work, we have developed a precise program to calculate the trajectory of each cosmic ray antiparticle to simulate the cosmic ray Sun shadow and study the influence of the magnetic field. With this program, we studied the influence of different magnetic field components between the Sun and the Earth, including the coronal magnetic field, interplanetary magnetic field, and geomagnetic field. Different magnetic field components have different influence on the shadow's displacement, extension and deficit, which is also energy dependent. In this work also checked two coronal magnetic field models, i.e., the potential field source surface (PFSS) model and the current sheet source surface (CSSS) model, their influence on Sun shadow were compared.