Simulations of Ultra High Energy Cosmic Rays propagation

TL;DR

This paper compares Monte Carlo and transport equation methods for simulating Ultra High Energy Cosmic Rays, finding they produce similar results with the transport method being significantly faster.

Contribution

It introduces a comparison between two simulation techniques for UHECR propagation, highlighting the efficiency of the transport equation approach.

Findings

Transport method is ~100 times faster than Monte Carlo.

Both methods yield practically identical results for proton/neutron primaries.

CRPropa and TransportCR codes are compatible with accuracy improvements.

Abstract

We compare two techniques for simulation of Ultra High Energy Cosmic Rays (UHECR) propagation, the Monte Carlo approach and method based on solving transport equations in one dimension. For the former we adopt publicly available tool CRPropa and for the later we use the code TransportCR developed by O.K. et al. and used in number of applications which is made available online with publishing this paper. While the CRPropa code is more universal, transport equation solver has advantage of roughly 100 times higher calculation speed. We conclude that the methods give practically identical results for the case of proton or neutron primaries provided that some accuracy improvements are introduced to CRPropa code.