Modulation of the galactic cosmic ray spectrum in an anisotropic diffusion approach

TL;DR

This paper presents a new anisotropic diffusion model for cosmic ray propagation in the Galaxy, accounting for magnetic field structure and turbulence, and explains spectral modulation around the CR knee.

Contribution

It introduces a novel anisotropic diffusion tensor model within a realistic Galactic magnetic field, advancing understanding of cosmic ray spectral modulation.

Findings

Spectral modulation occurs in the 1-30 PV rigidity range.

Changes in leakage mechanisms explain spectral variations.

Model aligns with current Galactic magnetic field data.

Abstract

We introduce a novel diffusion model for the propagation of cosmic rays (CRs) that incorporates an anisotropic diffusion tensor of a general form within a realistically modeled large-scale Galactic magnetic field. The parameters of the model are consistent with the contemporary understanding of the large-scale Galactic magnetic field structure and the dynamics of small-scale turbulent CR propagation. The paper demonstrates the modulation of spectra of Galactic cosmic rays (GCRs) in the magnetic rigidity range of 1 - 30 PV (the CR knee) and explores the spatial variation of this phenomenon. The observed modulation of the spectrum is explained by changes in the leakage mechanism.