aat Acta Astrophys. Tau. Acta Astrophysica Taurica 2712-925X Kiselev Nikolai Nikolaevich, Mosсow, settlement Moskovskii, Tat'yanin Park Str., 12, Moscow, Russia. RU 104 Magnetism and Activity of the Sun - 2023 Conference Proceedings Evolution of solar flare SOL 2013-05-17: analysis of optical spectra (Balmer series) and quasiperiodic pulsations Kupryakov Yurii Bychkov Konstantin Belova Oksana Gorshkov Aleksei Barta Miroslav Astronomical Institute of the Czech Academy of Sciences, Fricova 298, 25165 Ondrejov, Czech Republic; Sternberg Astronomical Institute, Moscow State University, Universitetsky pr. 13, Moscow 119234, Russia Sternberg Astronomical Institute, Moscow State University, Universitetsky pr. 13, Moscow 119234, Russia Sternberg Astronomical Institute, Moscow State University, Universitetsky pr. 13, Moscow 119234, Russia Sternberg Astronomical Institute, Moscow State University, Universitetsky pr. 13, Moscow 119234, Russia Astronomical Institute of the Czech Academy of Sciences, Fricova 298, 25165 Ondrejov, Czech Republic 22 03 2025 6 1 14 18 12 03 2025 Copyright (c) 2026 Kupryakov Y., Bychkov K., Belova O., Gorshkov A., Barta M. 2026 Yurii Kupryakov, Konstantin Bychkov, Oksana Belova, Aleksei Gorshkov, Miroslav Barta The metadata for this submission is licensed under a Creative Commons Attribution 4.0 International License. Copyright and publishing rights for texts published in Acta Astrophysica Taurica is retained by the authors, with first publication rights granted to the journal.Texts are free to use with proper attribution and link to the licensing (Creative Commons Attribution 4.0 International).

This work aims to study the behavior of radiation intensity curves in the Hε, Hβ, and Hα lines during the development of a flare and compare the results with calculated values. Observations were carried out with the horizontal solar telescope HSFA-2 (Ondrejov Observatory). The 2013-05-17 M3.2 flare in the NOAA AR 11748 was selected for processing, and the absolute values of fluxes in the spectral lines were determined. It is shown that the model of heating of the chromospheric gas by the flow of magnetohydrodynamic waves from the convective zone and its ionization and excitation by the flow of suprathermal particles from the corona satisfies the observations. Calculations are performed in hydrogen lines, taking into account the main processes that determine the radiation of gas, opaque in spectral lines. The flat decrement of the Balmer series indicates the inhomogeneity of the radiating region along the vertical. The search for quasiperiodic pulsations showed that in this flare they were found only in the Hα line with a significance level of 95%. They are absent in other spectral ranges.

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