On the initial orientation of emerging active regions

Abstract

The initial orientation of 74 active regions is measured in high resolution pictures. As previous works by the author (Garcia de la Rosa, 1984) suggest a different behaviour between large and small active regions, the sample has been divided into those two classes, whose dividing line is roughly set at 5 × 1021 Mx in the magnetic flux. It is observed that only the large regions tend to display the correct inclination (p-part at lower latitude). Their evolution towards a more parallel inclination to the equator is also observed.