УДК 523.985-125 Предсказания. Прогнозирование
УДК 52 Астрономия. Геодезия
УДК 53 Физика
УДК 520 Инструменты, приборы и методы астрономических наблюдений, измерений и анализа
УДК 521 Теоретическая астрономия. Небесная механика. Фундаментальная астрономия. Теория динамической и позиционной астрономии
УДК 523 Солнечная система
УДК 524 Звезды и звездные системы. Вселенная Солнце и Солнечная система
УДК 52-1 Метод изучения
УДК 52-6 Излучение и связанные с ним процессы
ГРНТИ 41.21 Солнце
ГРНТИ 41.00 АСТРОНОМИЯ
ГРНТИ 29.35 Радиофизика. Физические основы электроники
ГРНТИ 29.31 Оптика
ГРНТИ 29.33 Лазерная физика
ГРНТИ 29.27 Физика плазмы
ГРНТИ 29.05 Физика элементарных частиц. Теория полей. Физика высоких энергий
ОКСО 03.06.01 Физика и астрономия
ОКСО 03.05.01 Астрономия
ОКСО 03.04.03 Радиофизика
ББК 2 ЕСТЕСТВЕННЫЕ НАУКИ
ББК 223 Физика
ТБК 614 Астрономия
ТБК 6135 Оптика
BISAC SCI004000 Astronomy
BISAC SCI005000 Physics / Astrophysics
This paper considers the M6.5 eruptive solar flare occurred on June 22, 2015, for which ultraviolet preflare emission sources in the 1600 Å chromospheric channel have been analyzed using AIA/SDO data. Magnetic fields at the photospheric level are also analyzed using HMI/SDO vector magnetograms with a time resolution of 135 seconds. Since the selected flare has a long preflare phase (about one hour), the available time resolution of vector magnetograms is sufficient to study the flare and preflare dynamics of magnetic fields at the photospheric level. It can be noted that the literature mainly considers the change in currents during solar flares, while insufficient attention is paid to precursors. Our main goal is to provide continuous monitoring of the dynamics of electric current during the preflare period, at the beginning of the flare and during the main phases of the flare. We determined the magnetic flux (and its time derivative) in the preflare sources at the chromospheric level in comparison with the magnetic fluxes of the flare ribbons. Analysis of 135-second HMI photospheric vector magnetograms showed that there was an increase in the total vertical electric current about 1 hour before the flare. During this hour, there were variations of the mean vertical electric current density and its subsequent drop during the flare. We probably see an intermittent increase and dissipation of currents due to individual bursts in the preflare region. Also, the analysis of magnetic fluxes showed that, despite the weak preflare soft X-ray fluxes, the variations in magnetic flux during precursors are comparable in order of magnitude to what we see during the main phase of the solar flare. The difference between the time derivatives of the magnetic flux for precursor radiation sources and flare ribbons does not exceed a factor of 3.
Sun: solar flares; precursors; magnetic field; electric current
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