Solar Disk Gamma-Ray Emission via Synthetic Magnetic Field from Photosphere to Low Corona
Gamma-ray emission in the GeV–TeV range from the solar disk is likely to arise from collisions of galactic cosmic rays (GCRs) with solar atmospheric plasma. In a previous study, we demonstrated that closed turbulent magnetic arcades trap GCRs efficiently, leading to a gamma-ray flux consistent with...
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IOP Publishing
2025-01-01
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| Series: | The Astrophysical Journal Letters |
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| Online Access: | https://doi.org/10.3847/2041-8213/adf2a6 |
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| author | Eleonora Puzzoni Federico Fraschetti József Kóta Joe Giacalone |
| author_facet | Eleonora Puzzoni Federico Fraschetti József Kóta Joe Giacalone |
| author_sort | Eleonora Puzzoni |
| collection | DOAJ |
| description | Gamma-ray emission in the GeV–TeV range from the solar disk is likely to arise from collisions of galactic cosmic rays (GCRs) with solar atmospheric plasma. In a previous study, we demonstrated that closed turbulent magnetic arcades trap GCRs efficiently, leading to a gamma-ray flux consistent with the Fermi-HAWC observations (from ∼0.1 GeV to ∼1 TeV). Here, we model a synthetic magnetic field with a static, laminar structure of open field lines in the chromosphere, increasingly braided near the solar surface, with a scale height of ∼10 ^−2 R _⊙ . The height-dependent increase in magnetic field line braiding is modulated by an exponential scalar function, mimicking the bending of the photo- and chromospheric magnetic field revealed by polarimetric observations and reproduced by MHD simulations. Employing 3D test-particle numerical simulations, we investigate how distorted magnetic field lines affect the gamma-ray production by injecting GeV–TeV protons into both magnetically laminar and braided regions. We find that with the chosen spatial resolution, this synthetic magnetic field can account for the >10 GeV gamma-ray spectrum observed by Fermi/HAWC. A rebrightening between approximately 30 and 100 GeV (following a ∼30 GeV spectral dip) suggests an enhanced confinement within the photo-/chromospheric layer by stronger braiding. |
| format | Article |
| id | doaj-art-2bf65b97d99d4744bbf3f442cde08c1d |
| institution | Kabale University |
| issn | 2041-8205 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal Letters |
| spelling | doaj-art-2bf65b97d99d4744bbf3f442cde08c1d2025-08-20T03:39:29ZengIOP PublishingThe Astrophysical Journal Letters2041-82052025-01-019891L310.3847/2041-8213/adf2a6Solar Disk Gamma-Ray Emission via Synthetic Magnetic Field from Photosphere to Low CoronaEleonora Puzzoni0https://orcid.org/0009-0009-5314-348XFederico Fraschetti1https://orcid.org/0000-0002-5456-4771József Kóta2https://orcid.org/0000-0002-3715-0358Joe Giacalone3https://orcid.org/0000-0002-0850-4233Lunar and Planetary Laboratory, University of Arizona , 1629 E University Boulevard, Tucson, AZ 85721, USA ; epuzzoni@arizona.edu; Observatoire de la Côte d’Azur , Laboratoire Lagrange, Bd. de l’Observatoire, CS 34229, 06304 Nice cedex 4, FranceLunar and Planetary Laboratory, University of Arizona , 1629 E University Boulevard, Tucson, AZ 85721, USA ; epuzzoni@arizona.edu; Center for Astrophysics, Harvard & Smithsonian , 60 Garden Street, Cambridge, MA 02138, USALunar and Planetary Laboratory, University of Arizona , 1629 E University Boulevard, Tucson, AZ 85721, USA ; epuzzoni@arizona.eduLunar and Planetary Laboratory, University of Arizona , 1629 E University Boulevard, Tucson, AZ 85721, USA ; epuzzoni@arizona.eduGamma-ray emission in the GeV–TeV range from the solar disk is likely to arise from collisions of galactic cosmic rays (GCRs) with solar atmospheric plasma. In a previous study, we demonstrated that closed turbulent magnetic arcades trap GCRs efficiently, leading to a gamma-ray flux consistent with the Fermi-HAWC observations (from ∼0.1 GeV to ∼1 TeV). Here, we model a synthetic magnetic field with a static, laminar structure of open field lines in the chromosphere, increasingly braided near the solar surface, with a scale height of ∼10 ^−2 R _⊙ . The height-dependent increase in magnetic field line braiding is modulated by an exponential scalar function, mimicking the bending of the photo- and chromospheric magnetic field revealed by polarimetric observations and reproduced by MHD simulations. Employing 3D test-particle numerical simulations, we investigate how distorted magnetic field lines affect the gamma-ray production by injecting GeV–TeV protons into both magnetically laminar and braided regions. We find that with the chosen spatial resolution, this synthetic magnetic field can account for the >10 GeV gamma-ray spectrum observed by Fermi/HAWC. A rebrightening between approximately 30 and 100 GeV (following a ∼30 GeV spectral dip) suggests an enhanced confinement within the photo-/chromospheric layer by stronger braiding.https://doi.org/10.3847/2041-8213/adf2a6Solar gamma-ray emissionGalactic cosmic raysSolar magnetic fieldsSolar atmosphere |
| spellingShingle | Eleonora Puzzoni Federico Fraschetti József Kóta Joe Giacalone Solar Disk Gamma-Ray Emission via Synthetic Magnetic Field from Photosphere to Low Corona The Astrophysical Journal Letters Solar gamma-ray emission Galactic cosmic rays Solar magnetic fields Solar atmosphere |
| title | Solar Disk Gamma-Ray Emission via Synthetic Magnetic Field from Photosphere to Low Corona |
| title_full | Solar Disk Gamma-Ray Emission via Synthetic Magnetic Field from Photosphere to Low Corona |
| title_fullStr | Solar Disk Gamma-Ray Emission via Synthetic Magnetic Field from Photosphere to Low Corona |
| title_full_unstemmed | Solar Disk Gamma-Ray Emission via Synthetic Magnetic Field from Photosphere to Low Corona |
| title_short | Solar Disk Gamma-Ray Emission via Synthetic Magnetic Field from Photosphere to Low Corona |
| title_sort | solar disk gamma ray emission via synthetic magnetic field from photosphere to low corona |
| topic | Solar gamma-ray emission Galactic cosmic rays Solar magnetic fields Solar atmosphere |
| url | https://doi.org/10.3847/2041-8213/adf2a6 |
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