Propagation of Galactic cosmic rays: the influence of anisotropic diffusion

TL;DR

This paper models the anisotropic diffusion of cosmic rays in the Galaxy's magnetic field using stochastic differential equations, highlighting how perpendicular diffusion affects cosmic ray residence time and matter traversal.

Contribution

It introduces a numerical approach to simulate anisotropic cosmic ray diffusion considering the Galactic magnetic field's structure.

Findings

Perpendicular diffusion significantly influences cosmic ray residence time.

Anisotropic diffusion alters the grammage accumulated by cosmic rays.

The model provides insights into cosmic ray propagation dynamics.

Abstract

We investigate the anisotropic diffusion of cosmic rays in the large-scale Galactic magnetic field, where diffusion occurs at different rates along and across the magnetic field lines. To model this process, we use stochastic differential equations to describe cosmic ray propagation and solve them numerically. The Galactic magnetic field is modeled using the Jansson-Farrar prescription. In this study, we focus on the impact of perpendicular diffusion on the residence time of cosmic rays in the Galaxy. This allows us to estimate how anisotropic diffusion influences both the residence time and the total amount of matter (grammage) traversed by a typical cosmic ray during its journey through the Galaxy.