Does the local dynamo act in sunspot groups?

Previous results are summarized concerning the local magnetic field formation, showing that its sunspot groups developing to reach higher types C, D, E etc., continue their magnetic evolution during the period of new magnetic flux addition immediately after the first magnetically bipolar balanced stage. This is probably a magnetohydrodynamical process of magnetic field strengthening or a new magnetic flux generation. It is closely related to a specific singularity in the local magnetic field topology at the inner field boundary not far from the centre of the group, where the gulf of one polarity is compressed inbetween the boundary curvature of the field of opposite polarity and where large radial velocities may be observed. This is the region where new peaks of both the leading and the following polarities in a special orthogonal relation of the new to the old tubes of lines of force develop and where the greatest field gradients are formed. The flare frequencies and their importances correlate well with the degree of complexity of magnetic field topology in this situation. The important role of the photosphere in all these processes is underlined. (author). 2 figs., 30 refs