HelMod: A Comprehensive Treatment of the Cosmic Ray Transport Through the Heliosphere

TL;DR

HelMod is a Monte Carlo simulation tool that models the transport of Galactic cosmic rays through the heliosphere, accounting for drift effects and solar modulation, to better understand cosmic ray spectra near Earth.

Contribution

The paper introduces HelMod, a new 2-D Monte Carlo code that accurately models cosmic ray transport including drift effects and is compatible with GalProp.

Findings

Successfully fits observational data outside the ecliptic plane

Accurately reproduces cosmic ray spectra near Earth during different solar activity levels

Provides a new set of local interstellar spectra

Abstract

HelMod is a code evaluating the transport of Galactic cosmic rays through the inner heliosphere down to Earth. It is based on a 2-D Monte Carlo approach and includes a general description of the symmetric and antisymmetric parts of the diffusion tensor, thus, properly treating the particle drift effects. The model has been tuned in order to fit the data observed outside the ecliptic plane at several distances from the Earth and the spectra observed near the Earth for both, high and low solar activity levels. A stand-alone python module, fully compatible with GalProp, was developed for a comprehensive calculation of solar modulation effects, resulting in a newly suggested set of local interstellar spectra.