Problem of short-term predictions of solar flare activity

Structure of interrelation between seven variables characterizing flare activity was studied applying the methods of common factor analysis. I have analysed the question of the homogenity in the multivariable flare population. It was found that in the interconnection structure three factors appear, so I suggest solar flares conditioned by three different physical agents. It was also stated that the flare population is heterogeneous. This heterogeneity does not result from the Hα flare brightness differences but rather from the interconnection structure differences between small and strong X-ray flares. 18 refs., 8 figs., 3 tabs. (author)