Sites of flares and filaments in solar active regions

We applied a method developed to derive from magnetic field data the location of energy release in solar active regions. This method has been applied to two sets of data (June 13–15 1980 and June 23–25 1989) using magnetograms (Meudon, MSFC, Potsdam) and Hα data (Debrecen, MSDP Meudon). The Hα flares are located at intersections of the separatrices with the chromosphere in places where high density currents are observed. This supports the idea that the energy released in flares is due to magnetic reconnection at the location of a separator and subsequently transported to the chromosphere along field lines. It is found that strong magnetic shear is a necessary condition for filament formation. Magnetic shear merely determines the importance of the flare and is certainly not a necessary condition for flare activity.