Modelling of Shock-Accelerated Gamma-Ray Events

Afanasiev, Alexandr; Aran, A.; Vainio, Rami; Rouillard, A. P.; Zucca, Pietro; Lario, D.; Barcewicz, Suvi; Siipola, Robert; Pomoell, Jens; Malandraki, O.

doi:10.1007/978-3-319-60051-2_9

Cited by 6 publications

(2 citation statements)

References 13 publications

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“…Wijsen et al (2019a,b) have already combined EUHFORIA output with a novel SEP transport model solving the focused transport equation with Monte Carlo techniques. At the same time, advanced numerical simulation models have been developed for the acceleration and transport of particles in the corona enabling to get a deeper understanding of the complexity of the interaction between coronal shocks and solar magnetic fields (Afanasiev & Vainio, 2013;Afanasiev et al 2014Afanasiev et al , 2015Afanasiev et al , 2018aAfanasiev et al , 2018bVainio et al 2014).…”

Section: Key Science Questionsmentioning

confidence: 99%

EUropean Heliospheric FORecasting Information Asset 2.0

Poedts

Lani

Scolini

et al. 2020

J. Space Weather Space Clim.

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Aims This paper presents a H2020 project aimed at developing the world’s most advanced space weather forecasting tool, combining the MagnetoHydroDynamic (MHD) solar wind and Coronal Mass Ejection (CME) evolution modelling with Solar Energetic Particle (SEP) transport and acceleration model(s). The EUHFORIA 2.0 project will address the geoeffectiveness of impacts and mitigation to avoid (part of the) damage, including that of extreme events, related to solar eruptions, solar wind streams, and SEPs, with particular emphasis on its application to forecast Geomagnetically Induced Currents (GICs) and radiation on geospace. Methods We will apply innovative methods and state-of-the-art numerical techniques to extend the recent heliospheric solar wind and CME propagation model EUHFORIA with two integrated key facilities that are crucial for improving its predictive power and reliability, namely 1) data-driven flux-rope CME models, and 2) physics-based, self-consistent SEP models for the acceleration and transport of particles along and across the magnetic field lines. This involves the novel coupling of advanced space weather models. In addition, after validating the upgraded EUHFORIA/SEP model, it will be coupled to existing models for GICs and atmospheric radiation transport models. This will result in a reliable prediction tool for radiation hazards from SEP events, affecting astronauts, passengers and crew in high-flying aircraft, and the impact of space weather events on power grid infrastructure, telecommunication, and navigation satellites. Finally, this innovative tool will be integrated into both the Virtual Space Weather Modeling Centre (VSWMC, ESA) and the space weather forecasting procedures at the ESA SSCC in Uccle (Belgium), so that it will be available to the space weather community and effectively used for improved predictions and forecasts of the evolution of CME magnetic structures and their impact on Earth. Results The results of the first six months of the EU H2020 project are presented here. These concern alternative coronal models, the application of adaptive mesh refinement techniques in the heliospheric part of EUHFORIA, alternative flux-rope CME models, evaluation of data-assimilation based on Karman filtering for the solar wind modelling, and a feasibility study of the integration of SEP models.

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Section: Key Science Questionsmentioning

confidence: 99%

EUropean Heliospheric FORecasting Information Asset 2.0

Poedts

Lani

Scolini

et al. 2020

J. Space Weather Space Clim.

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“…Their simulations of the CMEdriven shock indicated that the quasi-perpendicular part of the shock had a magnetic connection to the gamma-ray source at the front-side of the Sun and the shock compression ratio increase matched the increase in the observed gamma-ray emission. Afanasiev et al (2018) simulated proton acceleration in the CME-driven shocks during the 2012 January 23 and May 17 SGRE events. The 2012 May 17 SGRE event was also observed as a GLE by neutron monitors.…”

Section: Introductionmentioning

confidence: 99%

Speed and Acceleration of Coronal Mass Ejections Associated with Sustained Gamma-Ray Emission Events Observed by Fermi/LAT

Mäkelä,

Gopalswamy,

Akiyama

et al. 2023

ApJ

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The sustained gamma-ray emission (SGRE) from the Sun is a prolonged enhancement of >100 MeV gamma-ray emission that extends beyond the flare impulsive phase. The origin of the >300 MeV protons resulting in SGRE is debated, with both flares and shocks driven by coronal mass ejections (CMEs) being the suggested sites of proton acceleration. We compared the near-Sun acceleration and space speed of CMEs with “Prompt” and “Delayed” (SGRE) gamma-ray components. We found that “Delayed”-component-associated CMEs have higher initial accelerations and space speeds than “Prompt Only”-component-associated CMEs. We selected halo CMEs (HCMEs) associated with type II radio bursts (shock-driving HCMEs) and compared the average acceleration and space speed between HCME populations with or without SGRE events, major solar energetic particle (SEP) events, metric, or decameter-hectometric (DH) type II radio bursts. We found that the SGRE-producing HCMEs associated with a DH type II radio burst and/or a major SEP event have higher space speeds and especially initial accelerations than those without an SGRE event. We estimated the radial distances and speeds of the CME-driven shocks at the end time of the 2012 January 23 and March 7 SGRE events using white-light images of STEREO Heliospheric Imagers and radio dynamic spectra of Wind WAVES. The shocks were at the radial distances of 0.6–0.8 au and their speeds were high enough (≈975 km s−1 and ≈750 km s−1, respectively) for high-energy particle acceleration. Therefore, we conclude that our findings support the CME-driven shock as the source of >300 MeV protons.

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Source of Energetic Protons in the 2014 September 1 Sustained Gamma-ray Emission Event

et al. 2020

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We report on the source of >300 MeV protons during the SOL2014-09-01 sustained gamma-ray emission (SGRE) event based on multi-wavelength data from a wide array of space-and groundbased instruments. Based on the eruption geometry we provide concrete explanation for the spatially and temporally extended γ-ray emission from the eruption. We show that the associated flux rope is of low inclination (roughly oriented in the east-west direction), which enables the associated shock to extend to the frontside. We compare the centroid of the SGRE source with the location of the flux rope's leg to infer that the high-energy protons must be precipitating between the flux rope leg and the shock front. The durations of the SOL2014-09-01 SGRE event and the type II radio burst agree with the linear relationship between these parameters obtained for other SGRE events with duration ≥3 hrs. The fluence spectrum of the SEP event is very hard, indicating the presence of high-energy (GeV) particles in this event. This is further confirmed by the presence of an energetic coronal mass ejection (CME) with a speed >2000 km/s, similar to those in ground level enhancement (GLE) events. The type II radio burst had emission components from metric to kilometric wavelengths as in events associated with GLE events. All these factors indicate that the high-energy particles from the shock were in sufficient numbers needed for the production of γ-rays via neutral pion decay.

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Modelling of Shock-Accelerated Gamma-Ray Events

Cited by 6 publications

References 13 publications

EUropean Heliospheric FORecasting Information Asset 2.0

EUropean Heliospheric FORecasting Information Asset 2.0

Speed and Acceleration of Coronal Mass Ejections Associated with Sustained Gamma-Ray Emission Events Observed by Fermi/LAT

Source of Energetic Protons in the 2014 September 1 Sustained Gamma-ray Emission Event

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