Reviews of topical problems

Modern analytic models of acceleration and propagation of electrons in solar flares

Lomonosov Moscow State University, Shternberg State Astronomical Institute, Universitetskii prosp. 13, Moscow, 119889, Russian Federation

We review the current state of the kinetic theory of acceleration and propagation of energetic (thermal and nonthermal) electrons during solar flares. The classical models of a thick target, together with their extension to models that take the reverse current effect and the acceleration of electrons in collapsing magnetic traps into account, are discussed in detail. Analytic solutions of the corresponding kinetic equations are found and used to calculate the characteristics of the hard X-ray bremsstrahlung generated by energetic electrons. The results obtained are compared with modern high-precision data from satellite observations of solar flares. The radiation polarization degree is calculated and the prospects for its measurement in future space experiments are discussed.

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Fulltext is also available at DOI: 10.3367/UFNe.2021.08.039048
Keywords: Sun, solar flares, electron acceleration, kinetic equation, collision integral, bremsstrahlung, polarization
PACS: 96.60.−j, 96.60.Iv, 96.60.qe, 96.60.Tf (all)
DOI: 10.3367/UFNe.2021.08.039048
Citation: Gritsyk P A, Somov B V "Modern analytic models of acceleration and propagation of electrons in solar flares" Phys. Usp. 66 437–459 (2023)
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Received: 28th, July 2021, revised: 20th, August 2021, 27th, August 2021

Оригинал: Грицык П А, Сомов Б В «Современные аналитические модели ускорения и распространения электронов в солнечных вспышках» УФН 193 465–490 (2023); DOI: 10.3367/UFNr.2021.08.039048

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