Propagation of Cosmic Ray Particles in the Earth’s Magnetic Field, as Defined by the IGRF and CHAOS Models

A model is created of the motion of galactic cosmic ray particles in the Earth’s magnetosphere, as defined by the IGRF and CHAOS models of the magnetic field. A second model contains a lithospheric field component that is missing from the first model. Power spectra are obtained for the flux of galactic cosmic rays at a fixed height above the Earth’s surface, and a difference is discovered at high orders of multipole expansion \(l > 7\) . When \(l > 20\) , the result can be explained by the contribution from the lithospheric component of the magnetic field in the CHAOS model, relative to the IGRF. When \(l \leqslant 20\) , it can be explained by the difference in the accuracy of describing the main field, since the IGRF is limited to the 13th order of expansion.