Relation between the toroidal field in the solar convective layer and the BI-polar field of sunspots

In the solar convective layer, there is a strong toroidal field and a vertical gradient in the turbulent magnetic diffusivity. As a fluid blob rises through magnetic buoyancy, a steep gradient in the turbulent magnetic diffusivity across the surface of the blob is generated. This will perturb the toroidal field, resulting in the formation of a magnetic ring around the blob. An attempt is made to account for the concentration of the bipolar sunspot field in terms of this ring.