Modelling the 2020 November 29 solar energetic particle event using the EUHFORIA and the iPATH model

TL;DR

This study couples EUHFORIA and iPATH models to simulate the 2020 November 29 SEP event, demonstrating the importance of realistic solar wind backgrounds and magnetic field configurations in accurately modeling SEP time profiles across multiple spacecraft.

Contribution

The paper introduces a coupled EUHFORIA-iPATH modeling approach for SEP events, highlighting the significance of realistic solar wind and magnetic field structures in simulation accuracy.

Findings

Realistic solar wind background significantly affects shock expansion.

Simulated SEP profiles match observed two-phase enhancements.

Perpendicular diffusion and magnetic field line distortion are key factors.

Abstract

We present the implementation of coupling the EUropean Heliospheric FORcasting Information Asset (EUHFORIA) and the improved Particle Acceleration and Transport in the Heliosphere (iPATH) model and simulate the widespread solar energetic particle (SEP) event of 2020 November 29. We compare the simulated time intensity profiles with measurements at Parker Solar Probe (PSP), the Solar Terrestrial Relations Observatory (STEREO)-A, SOlar and Heliospheric Observatory (SOHO) and Solar Orbiter (SolO). We focus on the influence of the history of shock acceleration on the varying SEP time intensity profiles and investigate the underlying causes in the origin of this widespread SEP event. The temporal evolution of shock parameters and particle fluxes during this event are examined. We find that adopting a realistic solar wind background can significantly impact the expansion of the shock and consequently the shock parameters. Time intensity profiles with an energetic storm particle event at PSP are well reproduced from the simulation. In addition, the simulated and observed time intensity profiles of protons show a similar two-phase enhancement at STA. These results illustrate that modelling a shock using a realistic solar wind is crucial in determining the characteristics of SEP events. The decay phase of the modelled time intensity profiles at Earth agrees well with observations, indicating the importance of perpendicular diffusion in widespread SEP events. Taking into account the possible large curved magnetic field line connecting to SolO, the modelled time intensity profiles show good agreement with the observation. We suggest that the largely distorted magnetic field lines due to a stream interaction region may be a key factor in understanding the observed SEPs at SolO in this event.