# Cosmic-Ray Anisotropy and the Local Interstellar Turbulence

## TL;DR

This paper investigates how local interstellar turbulence influences the large-scale anisotropy of cosmic-ray arrival directions at TeV-PeV energies, using models of magnetic turbulence to interpret observational data.

## Contribution

It introduces a model of cosmic-ray anisotropy based on pitch-angle diffusion in turbulent magnetic fields, linking turbulence properties to observed anisotropy patterns.

## Key findings

- Fits to IceTop data suggest certain turbulence parameters are consistent with observations.
- Some turbulence parameter ranges are ruled out by the data.
- The anisotropy shape can serve as a probe of interstellar turbulence properties.

## Abstract

We study the role of local interstellar turbulence in shaping the large-scale anisotropy in the arrival directions of TeV-PeV cosmic-rays (CRs) on the sky. Assuming pitch-angle diffusion of CRs in a magnetic flux tube containing the Earth, we compute the CR anisotropy for Goldreich-Sridhar turbulence, and for isotropic fast modes. The narrow deficits in the 400 TeV and 2 PeV data sets of IceTop can be fitted for some parameters of the turbulence. The data also rule out a part of the parameter space. The shape of the CR anisotropy may be used as a local probe of the still poorly known properties of the interstellar turbulence and of CR transport.