The Processes of Energy Release in Low-Power Solar Flares

Abstract

Using flare patrol data for 1972–2010 [http://www.ngdc.noaa.gov/stp/space-weather/solar-data/solar-features/solar-flares/], we have conducted statistical studies of small solar flares. We have established a correlation between the flare brightness rise time and the total duration of small flares, and obtained evidence of the discreteness of relative rise times (Trel). The most significant Trel values are 0.2, 0.25, 0.33, and 0.5. As the area class and importance of flares increase, maxima of Trel distributions decrease, flatten, and completely disappear in case of large flares. We have found the discreteness of the area distribution of small flares. We have obtained distributions of solar flare energy, which exhibit significant overlap for flare energy of different area classes. The energy range of large solar flares contains 9.5 % of small flares. The energy range of flares of area class 1 has even a more significant overlap.

Latitudinal distribution of solar microflares and high-temperature plasma at solar minimum

“…A small number of HXPs have been detected near the equator. Borovik and Zhdanov in [2018, 2019, 2020 have studied the flare events that can be considered as extremely powerful microflares, using data in the Hα line. It was found that during four solar cycles after cycle 21 there was a significant decrease in the number of flare events recorded in the optical range.…”