Longitudinal Dependence of Heavy Ion Composition in the 2021 October 28 Ground Level Enhancement Event
The 2021 October 28 solar energetic particle (SEP) event was a rare ground level enhancement (GLE) event, where secondary particles from the interactions of SEPs with the Earth’s atmosphere were detected by neutron monitors on the ground. A number of papers have examined the solar signatures, neutro...
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2025-01-01
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| author | C. M. S. Cohen G. M. Mason E. R. Christian A. C. Cummings G. A. de Nolfo M. I. Desai J. Giacalone M. E. Hill A. W. Labrador R. A. Leske D. J. McComas R. L. McNutt Jr D. G. Mitchell J. G. Mitchell G. D. Muro J. S. Rankin N. A. Schwadron M. M. Shen M. E. Wiedenbeck Z. G. Xu G. C. Ho R. F. Wimmer-Schweingrüber |
| author_facet | C. M. S. Cohen G. M. Mason E. R. Christian A. C. Cummings G. A. de Nolfo M. I. Desai J. Giacalone M. E. Hill A. W. Labrador R. A. Leske D. J. McComas R. L. McNutt Jr D. G. Mitchell J. G. Mitchell G. D. Muro J. S. Rankin N. A. Schwadron M. M. Shen M. E. Wiedenbeck Z. G. Xu G. C. Ho R. F. Wimmer-Schweingrüber |
| author_sort | C. M. S. Cohen |
| collection | DOAJ |
| description | The 2021 October 28 solar energetic particle (SEP) event was a rare ground level enhancement (GLE) event, where secondary particles from the interactions of SEPs with the Earth’s atmosphere were detected by neutron monitors on the ground. A number of papers have examined the solar signatures, neutron monitor observations, and the characteristics of the SEP protons and electrons for this event. Here we describe the heavy ion signatures, specifically O and Fe, observed by multiple spacecraft. Parker Solar Probe, Solar Terrestrial Relations Observatory-Ahead, and Advanced Composition Explorer were distributed over nearly 60° in solar longitude and 0.4 au in heliocentric distance. Despite their separations, all three spacecraft measured event-integrated O and Fe spectra, well represented by power laws, with nearly the same power-law index of approximately −1.7, which is significantly harder than most large SEP events and many GLE events. Moreover, the Fe/O abundance ratio determined from these spectra was also found to be spatially invariant over the 60° in longitude and 0.4 au in heliocentric distance. Such near uniformity is highly unusual, and only one similar occurrence was found in a previous multispacecraft. The observed Fe/O ratio of 0.39 is higher than typical for large SEP events but not unusual for GLE events. |
| format | Article |
| id | doaj-art-3d2a3cd3c5a84e1bb84d33d11bced46b |
| institution | Kabale University |
| issn | 2041-8205 |
| language | English |
| publishDate | 2025-01-01 |
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| series | The Astrophysical Journal Letters |
| spelling | doaj-art-3d2a3cd3c5a84e1bb84d33d11bced46b2025-01-08T12:18:18ZengIOP PublishingThe Astrophysical Journal Letters2041-82052025-01-019782L3510.3847/2041-8213/ada24bLongitudinal Dependence of Heavy Ion Composition in the 2021 October 28 Ground Level Enhancement EventC. M. S. Cohen0https://orcid.org/0000-0002-0978-8127G. M. Mason1https://orcid.org/0000-0003-2169-9618E. R. Christian2https://orcid.org/0000-0003-2134-3937A. C. Cummings3https://orcid.org/0000-0002-3840-7696G. A. de Nolfo4https://orcid.org/0000-0002-3677-074XM. I. Desai5https://orcid.org/0000-0002-7318-6008J. Giacalone6https://orcid.org/0000-0002-0850-4233M. E. Hill7A. W. Labrador8https://orcid.org/0000-0001-9178-5349R. A. Leske9https://orcid.org/0000-0002-0156-2414D. J. McComas10https://orcid.org/0000-0001-6160-1158R. L. McNutt Jr11https://orcid.org/0000-0002-4722-9166D. G. Mitchell12https://orcid.org/0000-0003-1960-2119J. G. Mitchell13https://orcid.org/0000-0003-4501-5452G. D. Muro14https://orcid.org/0000-0003-0581-1278J. S. Rankin15https://orcid.org/0000-0002-8111-1444N. A. Schwadron16https://orcid.org/0000-0002-3737-9283M. M. Shen17https://orcid.org/0000-0002-3093-458XM. E. Wiedenbeck18Z. G. Xu19https://orcid.org/0000-0002-9246-996XG. C. Ho20https://orcid.org/0000-0003-1093-2066R. F. Wimmer-Schweingrüber21https://orcid.org/0000-0002-7388-173XCalifornia Institute of Technology , Pasadena, CA 91125, USA ; cohen@srl.caltech.eduJohns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USAGoddard Space Flight Center , Greenbelt, MD 20771, USACalifornia Institute of Technology , Pasadena, CA 91125, USA ; cohen@srl.caltech.eduGoddard Space Flight Center , Greenbelt, MD 20771, USASouthwest Research Institute , San Antonio, TX 78228, USA; University of Texas at San Antonio , San Antonio, TX 78249, USAUniversity of Arizona , Tucson, AZ 85721, USAJohns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USACalifornia Institute of Technology , Pasadena, CA 91125, USA ; cohen@srl.caltech.eduCalifornia Institute of Technology , Pasadena, CA 91125, USA ; cohen@srl.caltech.eduDepartment of Astrophysical Sciences, Princeton University , Princeton, NJ 08544, USAJohns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USAJohns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USAGoddard Space Flight Center , Greenbelt, MD 20771, USACalifornia Institute of Technology , Pasadena, CA 91125, USA ; cohen@srl.caltech.eduDepartment of Astrophysical Sciences, Princeton University , Princeton, NJ 08544, USADepartment of Astrophysical Sciences, Princeton University , Princeton, NJ 08544, USA; University of New Hampshire , Durham, NH 03824, USADepartment of Astrophysical Sciences, Princeton University , Princeton, NJ 08544, USAJet Propulsion Laboratory, California Institute of Technology , Pasadena, CA 91109, USACalifornia Institute of Technology , Pasadena, CA 91125, USA ; cohen@srl.caltech.eduSouthwest Research Institute , San Antonio, TX 78228, USAInstitut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel , Kiel, GermanyThe 2021 October 28 solar energetic particle (SEP) event was a rare ground level enhancement (GLE) event, where secondary particles from the interactions of SEPs with the Earth’s atmosphere were detected by neutron monitors on the ground. A number of papers have examined the solar signatures, neutron monitor observations, and the characteristics of the SEP protons and electrons for this event. Here we describe the heavy ion signatures, specifically O and Fe, observed by multiple spacecraft. Parker Solar Probe, Solar Terrestrial Relations Observatory-Ahead, and Advanced Composition Explorer were distributed over nearly 60° in solar longitude and 0.4 au in heliocentric distance. Despite their separations, all three spacecraft measured event-integrated O and Fe spectra, well represented by power laws, with nearly the same power-law index of approximately −1.7, which is significantly harder than most large SEP events and many GLE events. Moreover, the Fe/O abundance ratio determined from these spectra was also found to be spatially invariant over the 60° in longitude and 0.4 au in heliocentric distance. Such near uniformity is highly unusual, and only one similar occurrence was found in a previous multispacecraft. The observed Fe/O ratio of 0.39 is higher than typical for large SEP events but not unusual for GLE events.https://doi.org/10.3847/2041-8213/ada24bSolar energetic particlesHeliosphereSolar coronal mass ejectionsSpace weather |
| spellingShingle | C. M. S. Cohen G. M. Mason E. R. Christian A. C. Cummings G. A. de Nolfo M. I. Desai J. Giacalone M. E. Hill A. W. Labrador R. A. Leske D. J. McComas R. L. McNutt Jr D. G. Mitchell J. G. Mitchell G. D. Muro J. S. Rankin N. A. Schwadron M. M. Shen M. E. Wiedenbeck Z. G. Xu G. C. Ho R. F. Wimmer-Schweingrüber Longitudinal Dependence of Heavy Ion Composition in the 2021 October 28 Ground Level Enhancement Event The Astrophysical Journal Letters Solar energetic particles Heliosphere Solar coronal mass ejections Space weather |
| title | Longitudinal Dependence of Heavy Ion Composition in the 2021 October 28 Ground Level Enhancement Event |
| title_full | Longitudinal Dependence of Heavy Ion Composition in the 2021 October 28 Ground Level Enhancement Event |
| title_fullStr | Longitudinal Dependence of Heavy Ion Composition in the 2021 October 28 Ground Level Enhancement Event |
| title_full_unstemmed | Longitudinal Dependence of Heavy Ion Composition in the 2021 October 28 Ground Level Enhancement Event |
| title_short | Longitudinal Dependence of Heavy Ion Composition in the 2021 October 28 Ground Level Enhancement Event |
| title_sort | longitudinal dependence of heavy ion composition in the 2021 october 28 ground level enhancement event |
| topic | Solar energetic particles Heliosphere Solar coronal mass ejections Space weather |
| url | https://doi.org/10.3847/2041-8213/ada24b |
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