Duration and fluence of major solar energetic particle (SEP) events

To understand solar energetic particle (SEP) events and their acceleration processes, it is important to study the SEP properties, e.g. duration and fluence. In this work, we analyzed the temporal evolution of fluxes [cm−2 sr−1 s−1]of>10, >30, and >60 MeV protons and the temporal and spectr...

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Detalles Bibliográficos
Autores: Firoz, Kazi A., Gan, W.Q., Li, Y.P., Rodríguez-Pacheco Martín, Javier|||0000-0002-4240-1115, Dorman, L.I.
Tipo de recurso: artículo
Fecha de publicación:2022
País:España
Institución:Universidad de Alcalá (UAH)
Repositorio:e_Buah Biblioteca Digital Universidad de Alcalá
Idioma:inglés
OAI Identifier:oai:ebuah.uah.es:10017/67452
Acceso en línea:http://hdl.handle.net/10017/67452
https://dx.doi.org/10.1007/s11207-022-01994-7
Access Level:acceso abierto
Palabra clave:SEP event
SEP fluence
SEP duration
Flares
Coronal shocks
Solar radio bursts
Coronal mass ejections
Física
Astronomía
Physics
Astronomy
Descripción
Sumario:To understand solar energetic particle (SEP) events and their acceleration processes, it is important to study the SEP properties, e.g. duration and fluence. In this work, we analyzed the temporal evolution of fluxes [cm−2 sr−1 s−1]of>10, >30, and >60 MeV protons and the temporal and spectral evolution of electromagnetic-radiation components for 34 major SEP events that include 13 ground-level enhancement (GLE)-SEP and 21 non-GLE-SEP events, and then determined their possible onset and end times [UT], their duration [hours], and fluence [cm−2 sr−1]. It is observed that the temporal fluxes of >30 MeV protons can sometimes be utilized for those of the fluxes of >10 MeV protons. Correspondence between SEP duration and fluence demonstrates the dependence of fluence on duration that helps distinguish the typical and atypical SEP events. For instance, for the >10 MeV protons, correspondence between the duration and fluence exhibited a weaker correlation (r ≈ 0.78; p<0.002) during the 13 GLE-SEPs than that (r ≈ 0.83; p<0.0001) during the 21 non-GLE-SEPs, revealing a few GLE-SEPs with disproportionate comparability. During the 13 GLE-SEPs, correspondence between the SEP duration and fluence for >30 MeV protons exhibited a stronger correlation (r ≈ 0.82; p<0.0006) than that (r ≈ 0.78; p<0.002) for the >10 MeV protons, indicating that the temporal window of >30 MeV protons is sometimes more appropriate for obtaining a reasonable duration of SEPs. Accordingly, when the temporal window of flux of >30 MeV protons is utilized for that of the >10 MeV protons, the correlation increased significantly (r ≈ 0.86; p<0.0002) during the 13 GLE-SEPs.