Solar-Terrestrial Physics Solar-Terrestrial Physics Solar-Terrestrial Physics 2500-0535 22242 10.12737/stp-42201803 Results of current research Results of current research Results of current research Statistical studies of duration of low-power solar flares Statistical studies of duration of low-power solar flares https://orcid.org/0000-0001-5725-8262 Боровик Александр Васильевич Borovik Aleksandr Vasil'evich aborovik@iszf.irk.ru

кандидат физико-математических наук;

candidate of physical and mathematical sciences;

 https://orcid.org/0000-0002-9563-1360 Жданов Антон Андреевич Zhdanov Anton Andreevich kick.out@mail.ru Институт солнечно-земной физики СО РАН Иркутск Россия Institute of Solar Terrestrial Physics SB RAS Irkutsk Russian Federation Институт солнечно-земной физики СО РАН Иркутск Россия Institute of Solar Terrestrial Physics SB RAS Irkutsk Russian Federation 4 2 8 16 https://zh-szf.ru/en/nauka/article/22242/view

This paper is a sequel to papers dealing with time parameters of solar flares in the Hα line. Using data from the international flare patrol for 1972–2010, we have determined the mean duration of flares of different importance and classes of area. We have established that 94.6 % of flares last more than 60 min. The duration of 90 % of flares with min is 2.1–3.3 hrs. In rare cases, flares can last about 12 hrs. The duration of powerful solar flares does not exceed 8.3 hrs. We have found that the duration of solar flares depends on features of their development. Flares with one brilliant point in the flare region have the shortest duration; two-ribbon flares and flares exhibiting several intensity maxima have the longest duration. We have confirmed that the duration of flares increases with increasing classes of area and brightness.

This paper is a sequel to papers dealing with time parameters of solar flares in the Hα line. Using data from the international flare patrol for 1972–2010, we have determined the mean duration of flares of different importance and classes of area. We have established that 94.6 % of flares last more than 60 min. The duration of 90 % of flares with min is 2.1–3.3 hrs. In rare cases, flares can last about 12 hrs. The duration of powerful solar flares does not exceed 8.3 hrs. We have found that the duration of solar flares depends on features of their development. Flares with one brilliant point in the flare region have the shortest duration; two-ribbon flares and flares exhibiting several intensity maxima have the longest duration. We have confirmed that the duration of flares increases with increasing classes of area and brightness.

 Solar activity Solar flares Solar activity Solar flares

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