The Relationship between Long-Duration Gamma-Ray Flares and Solar Cosmic Rays

Hudson, H. S.

doi:10.1017/s1743921317009681

Cited by 10 publications

(12 citation statements)

References 17 publications

(8 reference statements)

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“…This may be appropriate for some aspects of SEPs, as well as GCRs, given the likelihood that global coronal shock waves accelerate these particles. If this acceleration takes place on open fields, the SEPs that can return to the Sun and interact there may favor coronal holes (see Jin et al (2018) and Hudson (2018)). Of course the dominant γ-ray emission from solar flares also has a clear association with closed magnetic fields (Hurford et al 2003) associated with large sunspots.…”

Section: Discussionmentioning

confidence: 99%

Cosmic ray interactions in the solar atmosphere

Hudson

MacKinnon

Szydlarski

et al. 2019

Monthly Notices of the Royal Astronomical Society

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High-energy particles enter the solar atmosphere from Galactic or solar coronal sources, producing an "albedo" source from the quiet Sun, now observable across a wide range of photon energies. The interaction of high-energy particles in a stellar atmosphere depends essentially upon the joint variation of the magnetic field and the gas, which heretofore has been characterized parametrically as P ∝ B α with P the gas pressure and B the magnitude of the magnetic field. We re-examine that parametrization by using a self-consistent 3D MHD model (Bifrost) and show that this relationship tends to P ∝ B 2.9±0.1 based on the visible portions of the sample of open-field flux tubes in such a model, but with large variations from point to point. This scatter corresponds to the strong meandering of the open-field flux tubes in the lower atmosphere, which will have a strong effect on the prediction of the emission anisotropy (limb brightening). The simulations show that much of the open flux in coronal holes originates in weak-field regions within the granular pattern of the convective motions seen in the simulations.

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Section: Discussionmentioning

confidence: 99%

Cosmic ray interactions in the solar atmosphere

Hudson

MacKinnon

Szydlarski

et al. 2019

Monthly Notices of the Royal Astronomical Society

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“…However, after three hours, the region behind the blob will likely re-configure into a more dipole like structure. This would leave behind a large loop with seed particles, with those particles being unrelated to those in the impulsive phase, reminiscent of Hudson's lasso picture (Hudson 2018). ii.…”

Section: Discussionmentioning

confidence: 99%

Modeling the 2017 September 10 Long Duration Gamma Ray Flare

Ryan¹,

Nolfo²,

Gary³

2019

Proceedings of 36th International Cosmic Ray Conference — PoS(ICRC2019)

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to 10 were significant microwave events with revealing multi-wavelength images of the flare environment. The event on September 10 was a large long-duration, gamma-ray flare (LDGRF). The event also produced a Ground Level Enhancement (GLE). Using the constraints from the microwave imaging data from the Expanded Owens Valley Solar Array (EOVSA) we interpret and model the behavior of the energetic-flare protons of September 10 as measured with the Large Area Telescope (LAT) on the Fermi mission. We do this in the context of stochastic acceleration in a large coronal bipolar structure to produce the high-energy long-duration gamma-ray emission. Our preliminary analysis suggests that the acceleration of the GeV protons takes place in a large structure about 1.4 R ☉ in length. The requirements for the magnetic field and turbulence in this structure will be presented.

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“…Sep14 is the most intense and longest-lasting among the three behind-the-limb SGRE events observed by Fermi/LAT (Pesce-Rollins et al 2015a,b;Share et al 2018;Ackermann et al 2017;Plotnikov et al 2017;Jin et al 2018;Hudson 2018;Grechnev et al 2018). Plotnikov et al (2017), Ackermann et al (2017), and Share et al (2018) described the full time evolution of the SGRE flux.…”

Section: Data Descriptionmentioning

confidence: 99%

“…Open magnetic field lines (represented by the blue lines) in the sheath region that thread through the shock nose are rooted in the region beyond the dimming regions. Protons (>300 MeV, black coils) accelerated at the shock front travel along these open field lines precipitate to the solar chromosphere (indicated by the patches at the bottom of the blue lines) and produce γ-rays; the separation between the patches represents the largest spatial extent of the SGRE source.RecentlyHudson (2018) criticized the CME-shock solution by suggesting that a strong mirror force prevents protons from propagating sufficiently close to the Sun. The mirroring is a common problem to particles precipitating along any magnetic structure: PEA, flux rope, or the open structures threading the shock nose.…”

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confidence: 99%

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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The Relationship between Long-Duration Gamma-Ray Flares and Solar Cosmic Rays

Cited by 10 publications

References 17 publications

Cosmic ray interactions in the solar atmosphere

Cosmic ray interactions in the solar atmosphere

Modeling the 2017 September 10 Long Duration Gamma Ray Flare

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

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