Sunspot Configurations and Proton Flares

Practically all solar flares that emit energetic protons occur in sunspot groups with the Potsdam -configuraflon, in which sunspot umbras of opposite magnetic polarity appear close together within the same penumbra. This property is related to the known tendency of flares to occur where the magnetic field has a steep gradient, and to special flare-sunspot configurations identified earlier by other workers. The -configuration is a relatively reliable and easily recognizable symptom of major flare activity and particularly of proton emission.