Towards advanced forecasting of solar energetic particle events with the PARASOL model

TL;DR

This paper introduces PARASOL, a new model for forecasting solar energetic particle events, especially ESP events, by combining particle transport simulations with a semi-analytical foreshock description, validated on a 2012 SEP event.

Contribution

The paper presents the first version of PARASOL, integrating a semi-analytical foreshock model with particle transport simulations for improved SEP event forecasting.

Findings

PARASOL successfully simulated the 2012 SEP event near the shock.

The model reproduced observed ESP event intensities within one order of magnitude.

Validation demonstrates potential for advanced SEP forecasting.

Abstract

Gradual solar energetic particle (SEP) events are generally attributed to the particle acceleration in shock waves driven by coronal mass ejections (CMEs). Space-weather effects of such events are important, so there has been continuous effort to develop models able to forecast their various characteristics. Here we present the first version of a new such model with the primary goal to address energetic storm particle (ESP) events. The model, PARASOL, is built upon the PArticle Radiation Asset Directed at Interplanetary Space Exploration (PARADISE) test-particle simulation model of SEP transport, but includes a semi-analytical description of an inner (i.e., near the shock) part of the foreshock region. The semi-analytical foreshock description is constructed using simulations with the SOLar Particle Acceleration in Coronal Shocks (SOLPACS) model, which simulates proton acceleration self-consistently coupled with Alfven wave generation upstream of the shock, and subsequent fitting of the simulation results with suitable analytical functions. PARASOL requires input of solar wind and shock magnetohydrodynamic (MHD) parameters. We evaluate the performance of PARASOL by simulating the 12 July 2012 SEP event, using the EUropean Heliospheric FORecasting Information Asset (EUHFORIA) MHD simulation of the solar wind and CME in this event. The PARASOL simulation has reproduced the observed ESP event ($E \lesssim 5$ MeV) in the close vicinity of the shock within one order of magnitude in intensity.