Synthesis of 3‐D Coronal‐Solar Wind Energetic Particle Acceleration Modules

Schwadron, N. A.; Gorby, Matt; Török, Tibor; Downs, Cooper; Linker, J. A.; Lionello, R.; Mikić, Z.; Riley, Pete; Giacalone, J.; Chandran, B. D.; Germaschewski, K.; Isenberg, Phil A.; Lee, Martin A.; Lugaz, Noé; Smith, S. S.; Spence, H. E.; Desai, M. I.; Kasper, J. C.; Kozarev, Kamen; Korreck, K. E.; Stevens, Mike; Cooper, J. F.; MacNeice, P. J.

doi:10.1002/2014sw001086

Cited by 27 publications

(20 citation statements)

References 39 publications

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“…Finally, we would like to note that close-to-realistic simulations like the ones presented here should be employed for detailed investigations of specific aspects of solar eruptions. For example, our thermodynamic MHD simulation data are currently used to evaluate uncertainties in coronal electron temperature and speed measurements (Reginald et al, in preparation), and to model the acceleration and propagation of energetic particles (as described for a different simulation in Schwadron et al 2014). We encourage interested researchers to contact us if they would like to use our simulation data for complementary investigations.…”

Section: Summary and Discussionmentioning

confidence: 99%

Sun-to-Earth MHD Simulation of the 2000 July 14 “Bastille Day” Eruption

Török¹,

Downs²,

Linker³

et al. 2018

ApJ

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159

114

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Solar eruptions are the main driver of space-weather disturbances at the Earth. Extreme events are of particular interest, not only because of the scientific challenges they pose, but also because of their possible societal consequences. Here we present a magnetohydrodynamic (MHD) simulation of the 14 July 2000 "Bastille Day" eruption, which produced a very strong geomagnetic storm. After constructing a "thermodynamic" MHD model of the corona and solar wind, we insert a magnetically stable flux rope along the polarity inversion line of the eruption's source region and initiate the eruption by boundary flows. More than 10 33 ergs of magnetic energy are released in the eruption within a few minutes, driving a flare, an EUV wave, and a coronal mass ejection (CME) that travels in the outer corona at ≈ 1500 km s −1 , close to the observed speed. We then propagate the CME to Earth, using a heliospheric MHD code. Our simulation thus provides the opportunity to test how well in situ observations of extreme events are matched if the eruption is initiated from a stable magnetic-equilibrium state. We find that the flux-rope center is very similar in character to the observed magnetic cloud, but arrives ≈ 8.5 hours later and ≈ 15 • too far to the North, with field strengths that are too weak by a factor of ≈ 1.6. The front of the flux rope is highly distorted, exhibiting localized magnetic-field concentrations as it passes 1 AU. We discuss these properties with regard to the development of space-weather predictions based on MHD simulations of solar eruptions.

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Section: Summary and Discussionmentioning

confidence: 99%

Sun-to-Earth MHD Simulation of the 2000 July 14 “Bastille Day” Eruption

Török¹,

Downs²,

Linker³

et al. 2018

ApJ

Self Cite

159

114

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“…Tóth et al 2012;Manchester et al 2012) to study the acceleration and transport of protons in the solar corona during the 2005 May 13 SEP event. Schwadron et al (2014) introduce the The Coronal-Solar Wind Energetic Particle Acceleration (C-SWEPA) models by simulating the space weather effects of a synthetic extreme SEP event. The SEP transport and acceleration is modelled with EPREM.…”

Section: Introductionmentioning

confidence: 99%

Modelling three-dimensional transport of solar energetic protons in a corotating interaction region generated with EUHFORIA

Wijsen

Aran

Pomoell

et al. 2019

A&A

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Aims. We introduce a new solar energetic particle (SEP) transport code that aims at studying the effects of different background solar wind configurations on SEP events. In this work, we focus on the influence of varying solar wind velocities on the adiabatic energy changes of SEPs and study how a non-Parker background solar wind can trap particles temporarily at small heliocentric radial distances ( 1.5 AU) thereby influencing the cross-field diffusion of SEPs in the interplanetary space. Methods. Our particle transport code computes particle distributions in the heliosphere by solving the focused transport equation (FTE) in a stochastic manner. Particles are propagated in a solar wind generated by the newly developed data-driven heliospheric model, EUHFORIA. In this work, we solve the FTE, including all solar wind effects, cross-field diffusion, and magnetic-field gradient and curvature drifts. As initial conditions, we assume a delta injection of 4 MeV protons, spread uniformly over a selected region at the inner boundary of the model. To verify the model, we first propagate particles in nominal undisturbed fast and slow solar winds. Thereafter, we simulate and analyse the propagation of particles in a solar wind containing a corotating interaction region (CIR). We study the particle intensities and anisotropies measured by a fleet of virtual observers located at different positions in the heliosphere, as well as the global distribution of particles in interplanetary space. Results. The differential intensity-time profiles obtained in the simulations using the nominal Parker solar wind solutions illustrate the considerable adiabatic deceleration undergone by SEPs, especially when propagating in a fast solar wind. In the case of the solar wind containing a CIR, we observe that particles adiabatically accelerate when propagating in the compression waves bounding the CIR at small radial distances. In addition, for r 1.5 AU, there are particles accelerated by the reverse shock as indicated by, for example, the anisotropies and pitch-angle distributions of the particles. Moreover, a decrease in high-energy particles at the stream interface (SI) inside the CIR is observed. The compression/shock waves and the magnetic configuration near the SI may also act as a magnetic mirror, producing long-lasting high intensities at small radial distances. We also illustrate how the efficiency of the cross-field diffusion in spreading particles in the heliosphere is enhanced due to compressed magnetic fields. Finally, the inclusion of cross-field diffusion enables some particles to cross both the forward compression wave at small radial distances and the forward shock at larger radial distances. This results in the formation of an accelerated particle population centred on the forward shock, despite the lack of magnetic connection between the particle injection region and this shock wave. Particles injected in the fast solar wind stream cannot reach the forward shock since the SI acts as a diffusion barrier.

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“…This methodology is based on the approach described in Kóta et al (2005), which follows from the theory developed by Skilling (1971) and Ruffolo (1995). It was used by Kozarev et al (2013) to study timedependent effects of solar energetic particle (SEP) acceleration in the low corona during CME evolution and by Schwadron et al (2014) to model radiation doses at 1 au during a strong SPE event. In order to solve Equation (1), EPREM needs some model of n, B, and V at each node.…”

Section: Eprem Focused Transport Simulationsmentioning

confidence: 99%

Energetic Proton Propagation and Acceleration Simulated for the Bastille Day Event of 2000 July 14

Young

Schwadron

Gorby

et al. 2021

ApJ

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This work presents results from simulations of the 2000 July 14 ("Bastille Day") solar proton event. We used the Energetic Particle Radiation Environment Model (EPREM) and the CORona-HELiosphere (CORHEL) software suite within the SPE Threat Assessment Tool (STAT) framework to model proton acceleration to GeV energies due to the passage of a CME through the low solar corona, and we compared the model results to GOES-08 observations. The coupled simulation models particle acceleration from 1 to 20 R e , after which it models only particle transport. The simulation roughly reproduces the peak event fluxes and the timing and spatial location of the energetic particle event. While peak fluxes and overall variation within the first few hours of the simulation agree well with observations, the modeled CME moves beyond the inner simulation boundary after several hours. The model therefore accurately describes the acceleration processes in the low corona and resolves the sites of most rapid acceleration close to the Sun. Plots of integral flux envelopes from multiple simulated observers near Earth further improve the comparison to observations and increase potential for predicting solar particle events. Broken power-law fits to fluence spectra agree with diffusive acceleration theory over the low energy range. Over the high energy range, they demonstrate the variability in acceleration rate and mirror the interevent variability observed in solar cycle 23 ground-level enhancements. We discuss ways to improve STAT predictions, including using corrected GOES energy bins and computing fits to the seed spectrum. This paper demonstrates a predictive tool for simulating low-coronal solar energetic particle acceleration.

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Synthesis of 3‐D Coronal‐Solar Wind Energetic Particle Acceleration Modules

Abstract: Key Points Radiation from low corona Prompt SEP events from CME Large doses in 2 h

Cited by 27 publications

References 39 publications

Sun-to-Earth MHD Simulation of the 2000 July 14 “Bastille Day” Eruption

Sun-to-Earth MHD Simulation of the 2000 July 14 “Bastille Day” Eruption

Modelling three-dimensional transport of solar energetic protons in a corotating interaction region generated with EUHFORIA

Energetic Proton Propagation and Acceleration Simulated for the Bastille Day Event of 2000 July 14

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