Diffusion of cosmic rays at EeV energies in inhomogeneous extragalactic magnetic fields

Abstract

Ultra-high energy cosmic rays can propagate diffusively in cosmic magnetic fields. When their propagation time is comparable to the age of the universe, a suppression in the flux relative to the case in the absence of magnetic fields will occur. In this work we find an approximate parametrization for this suppression for energies below $\sim$ Z EeV using several magnetic field distributions obtained from cosmological simulations of the magnetized cosmic web. We assume that the magnetic fields have a Kolmogorov power spectrum with the field strengths distributed according to these simulations. We show that, if magnetic fields are coupled to the matter distribution, low field strengths will fill most of the volume, making the suppression milder compared to the case of a constant magnetic field with strength equal to the mean value of this distribution. We also derive upper limits for this suppression to occur for some models of extragalactic magnetic fields, as a function of the coherence length of these fields.

20 pages, 7 figures

References in corpus (5)

• Cluster Magnetic Fields from Galactic Outflows
• Constraints on the origin of cosmic rays above $10^{18}$ eV from large scale anisotropy searches in data of the Pierre Auger Observatory
• Inhomogeneous extragalactic magnetic fields and the second knee in the cosmic ray spectrum
• Non-Universal Spectra of Ultra-High Energy Cosmic Ray Primaries and Secondaries in a Structured Universe
• Cosmic Rays around $10^{18}$eV: Implications of Contemporary Measurements on the Origin of the Ankle Feature

Cited by in corpus (11)

• Simulations of extragalactic magnetic fields and of their observables
• Ultra-High-Energy Cosmic Rays: The Intersection of the Cosmic and Energy Frontiers
• Constraining models for the origin of ultra-high-energy cosmic rays with a novel combined analysis of arrival directions, spectrum, and composition data measured at the Pierre Auger Observatory
• Neutron β-decay as the origin of IceCube's PeV (anti)neutrinos
• Secondary neutrino and gamma-ray fluxes from SimProp and CRPropa
• Continuous Time Random Walk in a velocity field: Role of domain growth, Galilei-invariant advection-diffusion, and kinetics of particle mixing
• Ultra high energy cosmic rays from non-relativistic quasar outflows
• Magnetically Induced Anisotropies in the Arrival Directions of Ultra-high-energy Cosmic Rays from Nearby Radio Galaxies
• Effects of large-scale magnetic fields on the observed composition of ultra high-energy cosmic rays
• Effective Viscosity in the Intracluster Medium During Magnetic Field Amplification via Turbulent Dynamo
• Effects of extragalactic magnetic field on the spectra of ultra-high-energy cosmic rays from jetted sources