CRPropa

CRPropa is a publicly available simulation framework to study the propagation of ultra-high-energy nuclei up to iron on their voyage through an (extra)galactic environment. It takes into account: pion production, photodisintegration and energy losses by pair production of all relevant isotopes in the ambient low-energy photon fields as well as nuclear decay. CRPropa can model the deflection in (inter)galactic magnetic fields, the propagation of secondary electromagnetic cascades and neutrinos for a multitude of scenarios for different source distributions and magnetic environments. It enables the user to predict the spectra of UHECR (and of their secondaries), their composition and arrival direction distribution. Additionally, the low-energy Galactic propagation can be simulated by solving the transport equation using stochastic differential equations. CRPropa features a very flexible simulation setup with python steering and shared-memory parallelization.

Interactive Online Demo

You can try out CRPropa online at vispa.physik.rwth-aachen.de. Use the guest login and go to the CRPropa example via “VISPA Cluster” –> “Open Examples”.

Installation and Documentation

To install CRPropa, download and unzip either the

• latest release (recommended),

• or current development version.

Installation instructions, usage examples and API documentation can be found on the documentation web site of CRPropa.

Support

Please use the ticket system for support and in case of general questions. Please browse also the documentation and previous support requests on installation and usage of CRPropa before opening a new ticket.

To receive announcements etc., please subscribe to our mailing list by sending a mail with subject: subscribe crpropa-user to sympa@desy.de from the address you wish to subscribe.

How to cite CRPropa

If you use CRPropa 3.2 for your research, please cite

**JCAP (2022) no. 09, 035; arXiv:2208.00107**

as well as additional publications dependent on the components you are using.

Publications based on CRPropa

An extensive list of publications using CRPropa can be found via inSPIRE.

Plugins

Plugins are extensions of the core CRPropa framework, but they are not maintained by the CRPropa developer team. Instructions to install plugins can be found in the documentation.

Make sure to correctly cite the plugins when using them.

Name	Purpose	Link
FieldlineIntegrator	Magnetic Field Analysis	https://github.com/lukasmerten/CRPropa_FieldLineIntegrator
grplinst	Plasma Instabilities	https://github.com/rafaelab/grplinst
monopole	Magnetic Monopole Studies	https://github.com/chchristie/monopole/tree/main
ROOTOutputPlugin	Output into root file format	https://github.com/CRPropa/ROOTOutputPlugin

Contents

Project Info

• Installation
• Changelog
• FAQ
• How to cite CRPropa

USAGE

• Basic Concepts
  • Modular design
  • Parallelization/Multiprocessing
  • Unit system
  • Particle ID
  • Reference Counting
• Modules
  • Propagation modules
  • Interaction modules
  • Conditional modules
  • Observers
  • Output modules
  • Other modules
• Introduction to Python Steering
  • Simulation setup
  • Propagating a single particle
  • Defining an observer
  • Defining the output file
  • Defining the source
  • Running the simulation
  • (Optional) Plotting
• Extragalactic Propagation
  • 1D simulation
  • 4D Simulation
  • 3D trajectories in a turbulent field
  • 3D MHD models
  • Photon Propagation
  • Photon Propagation
  • Example with secondary neutrinos
  • Electromagnetic cascade example
  • The targeting algorithm of CRPropa
• Propagation of Extragalactic CR in the Milky Way
  • Galactic backtracking
  • Galactic Lensing of Simulated Cosmic Rays
  • Galactic Lensing of Maps
  • Galactic Lensing - confirm Liouville
  • Lambert’s distribution
• Galactic Cosmic Rays
  • Galactic trajectories
• Diffusion of Cosmic Rays
  • Diffusion Validation I
  • Diffusion Validation II
  • Advection and Adiabatic Energy Changes
  • Diffusive Shock Acceleration
  • Momentum Diffusion
  • Example of diffusion in the Milky way
  • Gas Densities
• Acceleration
  • Second Order Fermi Acceleration
  • First Order Fermi Acceleration
• Interfacing User Code
  • Implementing additional Modules and Features using Python only
  • Custom Observer
  • Custom Photon Fields
  • Using CRPropa from C++
• Comparison of Propagation Modules (BP - CK)
  • Analytic Solution
  • Helper Functions
  • Run Simulation
  • Load Simulation Data
  • Compare the Propagation in the Perpendicular Plane
  • Compare the Propagation in the Parallel Direction
  • Conservation of Momentum
  • Comparison with 3D Analytic Solution
  • Comparison of Simulation Time
  • Time Comparison for Galactic Trajectories
• Additional Resources

API

• Building Blocks
  • Core Classes
  • Physics Definitions
  • Propagation Modules
  • Energy Losses
  • Magnetic Fields
  • Observer
  • Condition
  • Source Features
  • Output
  • Magnetic Lenses
  • Tools
  • Photon Fields
• Library API
  • Class Hierarchy
  • File Hierarchy
  • Full API

DEVEL

• GNU Debugger (GDB)
• Profiling
• Code Coverage
• Verify the Data Files Integrity