A. G. Tlatov
Kislovodsk Station, Pulkovo Observatory, Russian Academy of Sciences, P.O. Box 1, Kislovodsk, 357741 Russia
Received January 15, 1996
Abstract—A model for the solar cycle in which the poloidal field is regenerated by the entrainment of magnetic
field in closed circulatory flows is investigated. These flows are concentrated in narrow layers near the base of
the convection zone and at the surface, and circulate from the equator to the poles at the surface and from the
poles to the equator at the convection zone base. A loop of new poloidal magnetic field forms close to the con-
vection zone base, near the poles. The poloidal field at the upper boundary of the flow is opposite to the poloidal
field of the current cycle and is the source of field for the new 11-year cycle; the sign of the poloidal field at the
lower boundary coincides with the direction for the poloidal field for the current cycle, but this field is confined
in a narrow layer between the base of the convection zone and the moving material. With time, the new poloidal
field loop is dragged by the moving flow from the poles to the equator, making the generation of toroidal
field possible via differential rotation and the change in sign of the magnetic field in the 11-year cycle.
Thecharacteristic time for the upward floating of the magnetic field captured between the convection zone
base and the nearby moving flow layer is much greater than eleven years, so that, in this region, the fields
from several cycles are superposed and partially compensate each other. Thus, near the convection zone
base, at the upper and lower boundaries of the flow, there are two layers which can have toroidal magnetic
field: the field at the upper boundary is responsible for the 11-year solar magnetic cycle, while the field at
the lower boundary may be associated with long-period variations in solar activity. Numerical calculations
modeling the cyclic variations of the solar magnetic activity and the topology of the cyclic sign change for
the surface magnetic field are presented.
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