Updated Model of the Solar Energetic Proton Environment in Space

TL;DR

This paper presents an updated, comprehensive model of the Solar Energetic Proton environment, improving predictions of proton fluxes across energies and periods, based on a carefully curated data set and new modeling techniques.

Contribution

The paper introduces an improved solar proton environment model with enhanced data processing, extrapolation methods, and comparison to previous models and observational data.

Findings

Model covers proton energies from 0.1 MeV to 1 GeV.

Provides outputs for mission fluence, maximum event fluence, and peak flux.

Shows better agreement with observational data than previous models.

Abstract

The Solar Accumulated and Peak Proton and Heavy Ion Radiation Environment (SAPPHIRE) model provides environment specification outputs for all aspects of the Solar Energetic Particle (SEP) environment. The model is based upon a thoroughly cleaned and carefully processed data set. Herein the evolution of the solar proton model is discussed with comparisons to other models and data. This paper discusses the construction of the underlying data set, the modelling methodology, optimisation of fitted flux distributions and extrapolation of model outputs to cover a range of proton energies from 0.1 MeV to 1 GeV. The model provides outputs in terms of mission cumulative fluence, maximum event fluence and peak flux for both solar maximum and solar minimum periods. A new method for describing maximum event fluence and peak flux outputs in terms of 1-in-x-year SPEs is also described. SAPPHIRE proton model outputs are compared with previous models including CREME96, ESP-PSYCHIC and the JPL model. Low energy outputs are compared to SEP data from ACE/EPAM whilst high energy outputs are compared to a new model based on GLEs detected by Neutron Monitors (NMs).