Modeling the 2012 May 17 Solar Energetic Particle Event Using the AWSoM and iPATH Models

Abstract

We model the 2012 May 17 solar energetic particle event by combining the AWSoM and iPATH codes. Using this combined approach, we investigate particle acceleration when the parent coronal mass ejection (CME) is still close to the Sun. We have obtained reasonable agreements between our simulation and observations made by multiple spacecraft. We follow the three-dimensional CME and the CME-driven shock from their initiation using the AWSoM code for a period of 3 hours when the shock is below ∼20 R s . Above 20 R s , iPATH2D is used to follow the CME-driven shock. The plasma properties from the AWSoM code are fed into the iPATH model, where particle acceleration at the shock front is modelled and the instantaneous energetic particle spectra are obtained. The subsequent transport of these energetic particles in the solar wind is followed using the iPATH model. We obtain both the instantaneous particle spectra and particle fluence at 1 au, and we then compare them with observations. To account for uncertainties of magnetic field connectivity from 1 au to the shock, as well as uncertainties of the shock profiles, our model’s results are obtained as an ensemble average where, instead of considering Earth as a single point location, we consider multiple locations within 10 degrees in longitude and latitude from Earth. The effect of this model uncertainty mimics that of the field line meandering, as suggested by Bian & Li, but is of different origin. We suggest that a trustworthy solar energetic particle forecast should be made in an ensemble average approach.

Extreme energetic particle events by superflare-associated CMEs from solar-like stars

“…Early applications of the 1D PATH code on individual SEP events have been pursued by Verkhoglyadova et al ( 37 , 38 ). Recently, the 2D iPATH code has been successfully used to reproduce the time profiles and event fluences for two large GLE events ( 39 , 40 ). These studies show the applicability of using the iPATH code and its capabilities to model extreme SEP and StEP events as pursued in this work.…”

Assessing the Influence of Input Magnetic Maps on Global Modeling of the Solar Wind and CME‐Driven Shock in the 2013 April 11 Event

“…We note that some studies have examined the uncertainties of the solar wind solutions due to magnetic data from different observatories (Gressl et al, 2014;Hayashi et al, 2016;Jian et al, 2015;Riley et al, 2014). There are also recent studies that compare the solar wind solutions from the diachronic and synchronic magnetic inputs based on either Potential Field Source Surface (PFSS) model (e.g., Caplan et al, 2021;Wallace et al, 2019) or MHD models (e.g., H. Li, et al, 2021;Linker et al, 2017).…”

Assessing the Influence of Input Magnetic Maps on Global Modeling of the Solar Wind and CME-driven Shock in the 2013 April 11 Event

“…The higher shock compression ratio and quasi-parallel nature found in the Case I also suggests the shock is a more efficient accelerator than in the Case II (Ding et al, 2020). However, due to the complex physical processes of the particle acceleration and transport involved, to quantitatively link the shock properties near the Sun to the SEP spectra at 1 AU requires advanced coupling between the MHD model and a particle acceleration/transport model (Young et al, 2021;G. Li et al, 2021), which is beyond the scope of this work and will be examined in a future study.…”