Energy spectra of x-ray flares in different active regions

We studied the integrated energy spectra of X-ray flares (1-8 Â, GOES) during 3 solar cycles (1977-2007). There is a positive correlation between spectrum value β and 11-year solar cycle during the flares in all active regions. This reflects the physical connection between them and the internal cause of the flare mechanism. The spectral index of all active regions demonstrates a noticeable 22-year modulation. Our findings can be used for the flare and dynamo theories.