University of Oulu

Koldobskiy, S., Raukunen, O., Vainio, R., Kovaltsov, G. A., & Usoskin, I. (2021). New reconstruction of event-integrated spectra (spectral fluences) for major solar energetic particle events. Astronomy & Astrophysics, 647, A132. https://doi.org/10.1051/0004-6361/202040058

New reconstruction of event-integrated spectra (spectral fluences) for major solar energetic particle events

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Author: Koldobskiy, S.1,2,3; Raukunen, O.4; R. Vainio4;
Organizations: 1University of Oulu, Oulu, Finland
2National Research Nuclear University MEPhI, Moscow, Russia
3St. Petersburg State University, St Petersburg, Russia
4University of Turku, Turku, Finland
5Ioffe Physical-Technical Institute, 194021 St. Petersburg, Russia
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 7 MB)
Persistent link: http://urn.fi/urn:nbn:fi-fe202103258389
Language: English
Published: EDP Sciences, 2021
Publish Date: 2021-03-25
Description:

Abstract

Aims.: Fluences of solar energetic particles (SEPs) are not easy to evaluate, especially for high-energy events (i.e. ground-level enhancements, GLEs). Earlier estimates of event-integrated SEP fluences for GLEs were based on partly outdated assumptions and data, and they required revisions. Here, we present the results of a full revision of the spectral fluences for most major SEP events (GLEs) for the period from 1956 to 2017 using updated low-energy flux estimates along with greatly revisited high-energy flux data and applying the newly invented reconstruction method including an improved neutron-monitor yield function.

Methods: Low- and high-energy parts of the SEP fluence were estimated using a revised space-borne/ionospheric data and ground-based neutron monitors, respectively. The measured data were fitted by the modified Band function spectral shape. The best-fit parameters and their uncertainties were assessed using a direct Monte Carlo method.

Results: A full reconstruction of the event-integrated spectral fluences was performed in the energy range above 30 MeV, parametrised and tabulated for easy use along with estimates of the 68% confidence intervals.

Conclusions: This forms a solid basis for more precise studies of the physics of solar eruptive events and the transport of energetic particles in the interplanetary medium, as well as the related applications.

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Series: Astronomy and astrophysics
ISSN: 0004-6361
ISSN-E: 1432-0746
ISSN-L: 0004-6361
Volume: 647
Article number: A132
DOI: 10.1051/0004-6361/202040058
OADOI: https://oadoi.org/10.1051/0004-6361/202040058
Type of Publication: A1 Journal article – refereed
Field of Science: 115 Astronomy and space science
Subjects:
Funding: This work was partially supported by the Academy of Finland (project No. 321882 ESPERA). Collection of the data from cosmic-ray/ionospheric experiments before 1989 and the creation of full dataset used in this work was supported by the Russian Science Foundation project no. 20-72-10170. Development of the fluence fitting procedure was supported by the Russian Science Foundation project no. 20-67-46016. The work in the University of Turku was performed in the framework of the Finnish Centre of Excellence in Research of Sustainable Space funded by the Academy of Finland (grant no. 312357).
Academy of Finland Grant Number: 321882
Detailed Information: 321882 (Academy of Finland Funding decision)
Dataset Reference: Detrended data of GLE recorded by NMs were obtained from the International GLE database https://gle.oulu.fi. PIs and teams of all the ground-based neutron monitors and space-borne experiments whose data were used here are gratefully acknowledged. The reconstructed fluences in tabulated form and the corresponding best-fit parameters are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/647/A132.
  https://gle.oulu.fi
http://cdsarc.u-strasbg.fr/
http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/647/A132
Copyright information: © ESO 2021.