Is there anyone knows, on how to analyze the active region which producing temporal evolution of solar flare? Means that, on how to calculate the range of the temporal evolution?
this is a very difficult and currently unsolved problem, since solar flares are very different and there is no single scenario for their evolution. If you are interested in changes in their magnetic fields obtained directly from the splitting of spectral lines in the Zeeman effect, the article that I am sending you in the accompanying file may be useful to you. In the list of references there are also links to other publications on this topic. Respectfully yours, Vsevolod Lozitsky.
Look up some of the papers of Cornelis de Jager on the matter: he had been a world authority on solar flares. Since he's won the German Astronomical Society's mathematical physics award, the same from the Russian Academy & both the French Janssons Award and the US Hale prize - along with the Royal Society's gold medal - I think somewhere you can get at least his old numbers in his very technical papers.