TILT-ANGLE VARIATIONS OF ACTIVE REGIONS

An examination of the tilt angles of multi-spot sunspot groups and pla ges shows that on average they tend to rotate toward the average tilt angle in each hemisphere. This average tilt angle is about twice as la rge for plages as it is for sunspot groups. The larger the deviation f rom the average tilt angle, the larger, on average, is the rotation of the magnetic axis in the direction of the average tilt angle. The rat e of rotation of the magnetic axis is about twice as fast for sunspot groups as it is for plages. Growing plages and spot groups rotate thei r axes significantly faster than do decaying plages and spot groups. T here is a latitude dependence of this effect that follows Joy's law. T he fact that these tilt angles move toward the average tilt angle and not toward 0 deg (the east-west orientation), combined with other resu lts presented here, suggest that a commonly accepted view of the origi n of active region magnetic flux at the solar surface may have to be r e-examined.