Peculiar Active Regions during the Last Two Solar Cycles

LÓPEZ FUENTES, M.C.; MANDRINI, C.H.; DÉMOULIN, P.; VAN DRIEL-GESZTELYI, L.

Córdoba

Congreso; X IAU Reunion Regional Latinoamericana de Astronomia; 2001

IAU

We perform a statistical study of the spatial and temporal distribution of \peculiar" active regions (ARs) along solar cycles 21 and 22. ARs usually appear in the photosphere in the form of bipolar concentrations of magnetic flux, by \peculiar" we mean regions in which the main polarities present a high tilt angle with respect to the solar equator (as compared to the average one, the so called Joy's law) and rotate one around the other along several solar rotations. Our results show that these regions are spatially distributed as usual ARs when no selection on their magnetic flux is applied. When classified according to their flux, ARs above 1022 Mx follow closely the buttery diagram; while those with lower  flux have a wider latitudinal distribution. Temporaly speaking the \peculiar" ARs follow the activity cycle, but their distribution is, in general, very structured with a clear tendency to show dual peak maxima. This kind of temporal evolution is also found in the number of the most energetic solar flares. We suggest that the studied ARs might be an important source of activity due to their magnetic complexity and unusual behavior.