New classification of solar flares based on the maximum flux in Soft X-rays and on duration of flare

Elena Bruevich

Published 2018-05-18Version 1

Solar flare activity is characterized by classification systems, both in optical and Soft X-ray ranges. The most generally accepted classifications of solar flares describe important parameters of flare such as the maximum of brightness of the flare in optical range in $H_{\alpha}$ (flare class in $H_{\alpha}$ is changed from F to B), area of the flare in $H_{\alpha}$ which is changed from S (less than 2 square degrees) to 4 (more than 24.7 square degrees) and the maximum amplitude of the Soft X-ray flux in the band 0.1-0.8 nm (X-ray flare of classes from C to X). A new classification of solar flares which is proposed in this paper -- the X-ray index of flare XI, based on measurements of radiation in the range 0.1-0.8 nm on the GOES satellites. The XI index has a clear physical interpretation associated with the total flare energy in the range 0.1-0.8 nm. XI is easily calculated for each flare with use of available GOES data. The XI index can be used to assess flares along with other important geoeffective parameters.