High-Resolution Spectral and Anisotropy Characteristics of Solar Protons During the GLE N(circle)73 on 28 October 2021 Derived with Neutron-Monitor Data Analysis
: Mishev Alexander L, Kocharov Leon G, Koldobskiy Sergey A, Larsen Nicholas, Riihonen Esa, Vainio Rami, Usoskin Ilya G
Publisher: SPRINGER
: 2022
: Solar Physics
: SOLAR PHYSICS
: SOL PHYS
: 88
: 297
: 7
: 23
: 0038-0938
DOI: https://doi.org/10.1007/s11207-022-02026-0
: https://link.springer.com/article/10.1007/s11207-022-02026-0
: https://research.utu.fi/converis/portal/detail/Publication/175917408
The first ground-level enhancement of the current Solar Cycle 25 occurred on 28 October 2021. It was observed by several space-borne and ground-based instruments, specifically neutron monitors. A moderate count-rate increase over the background was observed by high-altitude polar stations on the South Pole and Dome C stations at the Antarctic plateau. Most of the neutron monitors registered only marginal count-rate increases. Using detrended records and employing a method verified by direct space-borne measurements, we derive the rigidity spectra and angular distributions of the incoming solar protons in the vicinity of Earth. For the analysis, we employed a newly computed and parameterized neutron-monitor yield function. The rigidity spectra and anisotropy of solar protons were obtained in their time evolution throughout the event. A comparison with the Solar and Heliospheric Observatory/Energetic and Relativistic Nuclei and Electron (SOHO/ENRE) experiment data is also performed. We briefly discuss the results derived from our analysis.
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