Pole-ward motion and recoils of the boundaries of unipolar regionsPole-ward motion and recoils of the boundaries of unipolar regions
Faculty of Sciences. Physics
Department of Physics
SOLSPA 2001: proceedings of the second solar cycle and space weather euroconference
2nd Euroconference on Solar Cycle and Space Weather, SEP 24-29, 2001, VICO EQUENSE, ITALY
477(2002), p. 87-90
University of Antwerp
The large-scale unipolar zones have boundaries which practically coincide with filament bands encircling the whole Sun. Huge currents flow in these filament bands, which attract or repulse each other. When new unipolar zones are generated near the equator and thus new filament bands appear after a while. The previously existing filament bands feel a new repulsion attraction and a pole-ward motion starts. When a filament band reaches a pole and disappears (polar reversal) it releases the amount of "surface mass" it was holding and this pushes the other filament bands somewhat back, causing a "recoil". A more or less stationary situation may result in the second half of the sunspot cycle (after a polar reversal), in which the filament bands move slightly back an forth of their "equilibrium" latitude. Numerical estimates give reasonable acceleration and velocities, provided the filament bands are loaded by much more mass the they carry themselves: indeed they are anchored in the regions of unipolar field and thus form a connected piece like a sheet which may slip over the Sun.