A Babcock-Leighton flux transport dynamo with solar-like differential rotation

We investigate the properties of a kinematic flux transport solar dynamo mo del. The model is characterized by a solar-like internal differential rotat ion profile, a single-cell meridional flow in the convective envelope that is directed poleward at the surface, and a magnetic diffusivity that is con stant within the envelope but decreases sharply at the core-envelope interf ace. As in earlier flux transport models of the Babcock-Leighton type, we a ssume that the poloidal field is regenerated as a consequence of the emerge nce at the surface, and subsequent decay, of bipolar active regions exhibit ing a systematic tilt with respect to the east-west direction. Inspired by recent simulations of the rise of toroidal magnetic flux ropes across the s olar convective envelope, we model this poloidal field regeneration mechani sm as a nonlocal source term formulated in such a way as to account for som e of the properties of rising flux ropes revealed by the simulations. For a broad range of parameter values the model leads to solar cycle-like oscill atory solutions. Because of the solar-like internal differential rotation p rofile used in the model, solutions tend to be characterized by time-latitu de (butterfly) diagrams that exhibit both poleward- and equatorward-propaga ting branches. We demonstrate that the latitudinal shear in the envelope, o ften omitted in other flux transport models previously published in the lit erature, actually has a dominant effect on the global morphology and period of the solutions, while the radial shear near the core-envelope interface leads to further intensification of the toroidal field. On the basis of an extensive parameter space study, we establish a scaling law between the tim e period of the cycle and the primary parameters of the model, namely the m eridional flow speed, source coefficient, and turbulent diffusion coefficie nt. In the parameter regime expected to characterize the Sun, we show that the time period of the cycle is most significantly influenced by the circul ation flow speed and, unlike for conventional mean field alpha Omega dynamo s, is little affected by the magnitude of the source coefficient. Finally, we present one specific solution that exhibits features that compare advant ageously with the observed properties of the solar cycle.