New reconstruction of event-integrated spectra (spectral fluences) for major solar energetic particle events
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 Earlier estimates of event-integrated SEP fluences for GLEs were based on partly outdated assumptions and data, and they required revisions.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.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- March 2021
- DOI:
- 10.1051/0004-6361/202040058
- arXiv:
- arXiv:2101.10234
- Bibcode:
- 2021A&A...647A.132K
- Keywords:
-
- Sun: particle emission;
- Sun: flares;
- Sun: activity;
- solar-terrestrial relations;
- Astrophysics - Solar and Stellar Astrophysics;
- Physics - Space Physics
- E-Print:
- 19 pages, 3 figures, to be published in Astronomy and Astrophysics