Heliosphere Dimension and Cosmic Ray Modulation

TL;DR

This study models how the size of the heliosphere influences cosmic ray intensities at Earth, using a 2D stochastic approach, and finds that heliospheric size and solar activity significantly affect cosmic ray modulation.

Contribution

Introduces a diffusion model with heliospherical size dependence to better match cosmic ray observations and explores the impact of heliosphere shape on cosmic ray intensities.

Findings

Optimal heliospherical radius aligns with experimental data

Cosmic ray intensities vary with heliosphere size and solar activity

Results agree with Voyager observations and existing modulation models

Abstract

The differential intensities of Cosmic Rays at Earth were calculated using a 2D stochastic Montecarlo diffusion code and compared with observation data. We evaluated the effect of stretched and compressed heliospheres on the Cosmic Ray intensities at the Earth. This was studied introducing a dependence of the diffusion parameter on the heliospherical size. Then, we found that the optimum value of the heliospherical radius better accounting for experimental data. We also found that the obtained values depends on solar activity. Our results are compatible with Voyager observations and with models of heliospherical size modulation.