The emission in the region e > 0.1 MeV during disk and limb faint solar flares . Advances in Space Research Volume 51, Issue 11, 2013, Pages 1996-2001

Hard X-ray and gamma-ray emission in energy band E>50 keV was first observed by AVS-F apparatus onboard CORONAS-F satellite (detector SONG-D) during some solar flares with classes B and C by GOES classification. Such component registered in flares with duration less than 30 min. However γ-emission up to several tens of MeV was observed during some classes B and C events, which temporal profiles were not corresponded to Neupert effect. For example, during class B2.3 limb solar flare January 7, 2005 maximum observed energy was Emax∼36 MeV and during class B4.6 disk solar event January 12, 2005 maximum observed energy was Emax∼7 MeV. Properties of temporal profiles and energy spectra of faint solar flares, during which emission in the energy band of E>0.1 MeV were registered are discussed in the presented work. There is not any strong correlation between presence or absence of hard X-ray and γ-ray emission and the intensity of soft X-ray emission during solar flares. The one of illustration of this fact is the absence of any observed statistically significant count rate exceed above background level during some class M flares in the energy band E>0.1 MeV. The typical example of such flares is event November 8, 2001 (class M4.2, lasts from 14:59 UT up to 16:00 UT, maximum of soft X-ray emission was at 15:35 UT on GOES data). © 2012 COSPAR. Published by Elsevier Ltd.



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Author keywords

CORONAS-F satellite; Faint solar flares; High energy γ-emission



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Indexed keywords

Background level; CORONAS-F; Energy spectra; Gamma-ray emission; Soft x-ray emissions; Solar flare; Strong correlation; Temporal profile