University of Oulu

Mishev, A., Usoskin, I., Koldobskiy, S., Kovaltsov, G., & Kocharov, L. (2021, June 24). Application of the verified neutron monitor yield function for GLE analysis. Proceedings of 37th International Cosmic Ray Conference — PoS(ICRC2021). 37th International Cosmic Ray Conference.

Application of verified neutron monitor yield function for GLE analysis

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Author: Mishev, Alexander1,2; Usoskin, Ilya1,2; Koldobskiy, Sergey2,3;
Organizations: 1Sodankylä Geophysical Observatory, University of Oulu, Finland
2Space Physics and Astronomy Research Unit, University of Oulu, Finland
3National Research Nuclear University MEPhI, Moscow, Russia
4Ioffe Physical-Technical Institute, St. Petersburg, Russia
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 0.9 MB)
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Language: English
Published: Sissa, 2021
Publish Date: 2021-08-16


Systematic study of solar energetic particles provides an important basis to understand their acceleration and propagation in the interplanetary space. After solar eruptive processes, such as solar flares and/or coronal mass ejections, solar ions are accelerated to high energy. In the majority of cases, the maximum energy of the accelerated solar ions is several tens of MeV/nucleon, but in some cases, it exceeds 100 MeV/nucleon or even reaches the GeV/nucleon range. In this case, the energy is high enough, so that solar ions generate an atmospheric cascade in the Earth’s atmosphere, whose secondary particles reach the ground, being eventually registered by ground-based detectors, specifically neutron monitors. This particular class of events is known as ground-level enhancements (GLEs). Several methods for analysis of GLEs, using neutron monitor data were developed over the years. Here, we present a method for assessment of the spectral and angular characteristics of the GLEs using data from the world-wide NM network, namely by modeling the global neutron monitor network response with a new verified yield function. The method is based on consecutive steps, specifically detailed computation of asymptotic cones and rigidity cut-off of each station used in the analysis and optimization of the global neutron monitor response over experimental and modeled count rate increases. The method is compared with other methods, including in-situ measurements. A very good agreement between our method and space-borne measurements with PAMELA space probe, specifically the derived fluence of solar protons during GLE 71 was achieved, therefore verification of the method is performed.

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Series: POS. Proceedings of science
ISSN: 1824-8039
ISSN-E: 1824-8039
ISSN-L: 1824-8039
Volume: 395
Article number: 1236
DOI: 10.22323/1.395.1236
Host publication: Proceedings of 37th International Cosmic Ray Conference (ICRC2021)
Conference: International Cosmic Ray Conference
Type of Publication: B3 Article in conference proceedings
Field of Science: 115 Astronomy and space science
Funding: This work was supported by the Academy of Finland (project 330064 QUASARE, 330427 HEAIM 2 and 321882 ESPERA).
Academy of Finland Grant Number: 330064
Detailed Information: 330064 (Academy of Finland Funding decision)
330427 (Academy of Finland Funding decision)
321882 (Academy of Finland Funding decision)
Copyright information: © Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND 4.0).