Credit: Puzzoni et al. 2026

A new web-based tool for galactic cosmic rays in the heliosphere

Galactic Cosmic Rays (GCRs) play a critical role in space weather forecasting and radiation hazard assessment for deep space missions. Accurate modeling of GCR flux throughout the heliosphere is therefore crucial. This paper describes the physical model and the functionality of a new user-friendly web-based tool designed to rapidly estimate the energy spectrum and flux of GCRs using minimal user input such as radial distance, time, and energy. The tool is based on the force-field approximation to the Parker transport equation and incorporates solar modulation via the correlation between GCRs and the mean sunspot number. Compared to existing Monte Carlo or finite-difference-based models which include a more physically realistic model of the heliosphere, this simpler 1D spherical model offers significant advantages in computational speed and ease of use. The tool is validated against spacecraft data from Voyager 1, Voyager 2, and New Horizons, and is capable of projecting future GCR spectra and fluxes based on sunspot number predictions. The key aim is to provide a very rapid estimate of GCR properties using a physics-based model that is constructed to fit as many data sets as possible. The tool will continue to be modified as new data sets are added, with the platform also serving as a data repository. Designed for both researchers and the general public, the platform also serves as an educational resource on GCRs and heliospheric physics. 

Credit: Puzzoni et al. 2026

At 1 AU, modulation potential is known back approximately 1000 years. This deep historical record is made possible by integrating recent tree-ring measurements from Brehm et al. 2025 extending our predictive baseline far prior the Voyager era. The tool can predict future sunspot numbers up to 10 years from today. 

This GCR web-based tool is part of the SHIELD (Solar wind with Hydrogen Ion charge Exchange and Large-Scale Dynamics) project, a NASA DRIVE Center focused, among other goals, on advancing our understanding of the heliosphere (our protective shield), and determining how GCRs are filtered and transported through it.