The Characteristics of the X-ray Flares (1-8, GOES) of the Different Classes and Their Variations in Two Cycles of Solar Activity

The X-ray (1-8Å)flux data of the solar flares are analyzed.The data used were obtained on GOES satellite during the solar cycles 21 and 22.The total number of the flares is more than 33000.The flare distributions according to their X-ray-classes, durations and intensities are const ructed.The evolution of these distributions in solar cycle as well as from cycle to cycle is studied.The statistical analysis of the flare characteristics is made.There was confirmed the result of more frequent occurrence for powerful flares in cycle 21 decline phase.