Solar energetic particle events with extremely high 3He content observed by Solar Orbiter

We performed a survey of 3He-rich events using observations from the Suprathermal Ion Spectrograph on the Solar Orbiter mission from 2020 to 2024. We identified 57 3He-rich events, each showing clear 3He enhancements above the background and 3He/4He abundance ratios greater than 1 in at least one en...

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Autores: Kouloumvakos, Athanasios, Mason, Glenn M., Ho, George C., Allen, Robert C., Rodríguez-Pacheco Martín, Javier|||0000-0002-4240-1115, Wimmer-Schweingruber, R. F.
Tipo de recurso: artículo
Fecha de publicación:2025
País:España
Institución:Universidad de Alcalá (UAH)
Repositorio:e_Buah Biblioteca Digital Universidad de Alcalá
Idioma:inglés
OAI Identifier:oai:ebuah.uah.es:10017/67372
Acceso en línea:http://hdl.handle.net/10017/67372
https://dx.doi.org/10.3847/1538-4357/adbae7
Access Level:acceso abierto
Palabra clave:Astronomía
Física
Astronomy
Physics
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spelling Solar energetic particle events with extremely high 3He content observed by Solar OrbiterKouloumvakos, AthanasiosMason, Glenn M.Ho, George C.Allen, Robert C.Rodríguez-Pacheco Martín, Javier|||0000-0002-4240-1115Wimmer-Schweingruber, R. F.AstronomíaFísicaAstronomyPhysicsWe performed a survey of 3He-rich events using observations from the Suprathermal Ion Spectrograph on the Solar Orbiter mission from 2020 to 2024. We identified 57 3He-rich events, each showing clear 3He enhancements above the background and 3He/4He abundance ratios greater than 1 in at least one energy channel in the range from 193.2 keV nucleon−1 to 8.74 MeV nucleon−1. The analysis of the events’ abundance ratios shows characteristics of impulsive solar energetic particle events with 3He/4He ∼ 3.1 and Fe/O ∼ 1.3. We observe an energy dependence in the 3He/4He ratio, which increases with energy, while the Fe/O ratios are almost constant with energy. We also found that six events in our list have extremely high 3He content (e.g., 3He/C–Fe ratios in the range 25–62). These events show curved 3He and heavy nuclei spectra that roll over at higher energies and flatten toward low energy. Their spectral forms can be reasonably fit with simple exponentials with a 3He rollover energy in the range of a few hundred keV per nucleon and a C–Fe rollover energy ∼2–3 times lower. The differences in spectral rollover energy lead to a strong energy dependence of the ratio 3He/C–Fe, rising sharply with energy. We conclude that the features of these events with extremely high 3He content have a reasonable likelihood of depicting the initial acceleration process, which is driven by magnetic reconnection in flaring loops near the solar surface.American Astronomical Society20252025-04-07journal articlehttp://purl.org/coar/resource_type/c_6501NAhttp://purl.org/coar/version/c_be7fb7dd8ff6fe43info:eu-repo/semantics/articleapplication/pdfhttp://hdl.handle.net/10017/67372https://dx.doi.org/10.3847/1538-4357/adbae7reponame:e_Buah Biblioteca Digital Universidad de Alcaláinstname:Universidad de Alcalá (UAH)Inglésengopen accesshttp://purl.org/coar/access_right/c_abf2Attribution 4.0 Internationalhttp://creativecommons.org/licenses/by/4.0/info:eu-repo/semantics/openAccessoai:ebuah.uah.es:10017/673722026-06-18T11:13:07Z
dc.title.none.fl_str_mv Solar energetic particle events with extremely high 3He content observed by Solar Orbiter
title Solar energetic particle events with extremely high 3He content observed by Solar Orbiter
spellingShingle Solar energetic particle events with extremely high 3He content observed by Solar Orbiter
Kouloumvakos, Athanasios
Astronomía
Física
Astronomy
Physics
title_short Solar energetic particle events with extremely high 3He content observed by Solar Orbiter
title_full Solar energetic particle events with extremely high 3He content observed by Solar Orbiter
title_fullStr Solar energetic particle events with extremely high 3He content observed by Solar Orbiter
title_full_unstemmed Solar energetic particle events with extremely high 3He content observed by Solar Orbiter
title_sort Solar energetic particle events with extremely high 3He content observed by Solar Orbiter
dc.creator.none.fl_str_mv Kouloumvakos, Athanasios
Mason, Glenn M.
Ho, George C.
Allen, Robert C.
Rodríguez-Pacheco Martín, Javier|||0000-0002-4240-1115
Wimmer-Schweingruber, R. F.
author Kouloumvakos, Athanasios
author_facet Kouloumvakos, Athanasios
Mason, Glenn M.
Ho, George C.
Allen, Robert C.
Rodríguez-Pacheco Martín, Javier|||0000-0002-4240-1115
Wimmer-Schweingruber, R. F.
author_role author
author2 Mason, Glenn M.
Ho, George C.
Allen, Robert C.
Rodríguez-Pacheco Martín, Javier|||0000-0002-4240-1115
Wimmer-Schweingruber, R. F.
author2_role author
author
author
author
author
dc.subject.none.fl_str_mv Astronomía
Física
Astronomy
Physics
topic Astronomía
Física
Astronomy
Physics
description We performed a survey of 3He-rich events using observations from the Suprathermal Ion Spectrograph on the Solar Orbiter mission from 2020 to 2024. We identified 57 3He-rich events, each showing clear 3He enhancements above the background and 3He/4He abundance ratios greater than 1 in at least one energy channel in the range from 193.2 keV nucleon−1 to 8.74 MeV nucleon−1. The analysis of the events’ abundance ratios shows characteristics of impulsive solar energetic particle events with 3He/4He ∼ 3.1 and Fe/O ∼ 1.3. We observe an energy dependence in the 3He/4He ratio, which increases with energy, while the Fe/O ratios are almost constant with energy. We also found that six events in our list have extremely high 3He content (e.g., 3He/C–Fe ratios in the range 25–62). These events show curved 3He and heavy nuclei spectra that roll over at higher energies and flatten toward low energy. Their spectral forms can be reasonably fit with simple exponentials with a 3He rollover energy in the range of a few hundred keV per nucleon and a C–Fe rollover energy ∼2–3 times lower. The differences in spectral rollover energy lead to a strong energy dependence of the ratio 3He/C–Fe, rising sharply with energy. We conclude that the features of these events with extremely high 3He content have a reasonable likelihood of depicting the initial acceleration process, which is driven by magnetic reconnection in flaring loops near the solar surface.
publishDate 2025
dc.date.none.fl_str_mv 2025
2025-04-07
dc.type.none.fl_str_mv journal article
http://purl.org/coar/resource_type/c_6501
NA
http://purl.org/coar/version/c_be7fb7dd8ff6fe43
dc.type.openaire.fl_str_mv info:eu-repo/semantics/article
format article
dc.identifier.none.fl_str_mv http://hdl.handle.net/10017/67372
https://dx.doi.org/10.3847/1538-4357/adbae7
url http://hdl.handle.net/10017/67372
https://dx.doi.org/10.3847/1538-4357/adbae7
dc.language.none.fl_str_mv Inglés
eng
language_invalid_str_mv Inglés
language eng
dc.rights.none.fl_str_mv open access
http://purl.org/coar/access_right/c_abf2
Attribution 4.0 International
http://creativecommons.org/licenses/by/4.0/
dc.rights.openaire.fl_str_mv info:eu-repo/semantics/openAccess
rights_invalid_str_mv open access
http://purl.org/coar/access_right/c_abf2
Attribution 4.0 International
http://creativecommons.org/licenses/by/4.0/
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
dc.publisher.none.fl_str_mv American Astronomical Society
publisher.none.fl_str_mv American Astronomical Society
dc.source.none.fl_str_mv reponame:e_Buah Biblioteca Digital Universidad de Alcalá
instname:Universidad de Alcalá (UAH)
instname_str Universidad de Alcalá (UAH)
reponame_str e_Buah Biblioteca Digital Universidad de Alcalá
collection e_Buah Biblioteca Digital Universidad de Alcalá
repository.name.fl_str_mv
repository.mail.fl_str_mv
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