Cosmic Ray transport in mixed magnetic fields and their role on the observed anisotropies

TL;DR

This paper introduces a Monte Carlo transport method to analyze how finite-scale magnetic fields influence small-scale cosmic ray anisotropies, addressing limitations of standard diffusion models.

Contribution

It presents a novel Monte Carlo approach to study cosmic ray transport in finite-scale magnetic fields, improving understanding of observed anisotropies.

Findings

Finite-scale magnetic fields can produce small-scale anisotropies consistent with observations.

Standard diffusion models do not adequately capture transport physics in structured magnetic media.

Monte Carlo simulations reveal specific magnetic field configurations that explain anisotropy features.

Abstract

There is a growing set of observational data demonstrating that cosmic rays exhibit small-scale anisotropies (5-30 deg) with amplitude deviations lying between 0.01-0.1 percent that of the average cosmic ray flux. A broad range of models have been proposed to explain these anisotropies ranging from finite-scale magnetic field structures to dark matter annihilation. The standard diffusion transport methods used in cosmic ray propagation do not capture the transport physics in a medium with finite-scale or coherent magnetic field structures. Here, we present a Monte Carlo transport method, applying it to a series of finite-scale magnetic field structures to determine the requirements of such fields in explaining the observed cosmic ray,small-scale anisotropies.