Classification of Solar Flares Based on the Maximum Flux in Soft X–rays and on Duration of Flare

Abstract

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 α (flare class in H α is changed from F to B), area of the flare in H α 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.