  One important ingredient of flux transport dynamo models is the rise of the
toroidal magnetic field through the convection zone due to magnetic buoyancy to
produce bipolar sunspots and then the generation of the poloidal magnetic field
from these bipolar sunspots due to the Babcock-Leighton mechanism. Over the
years, two methods of treating magnetic buoyancy, a local method and a
non-local method have been used widely by different groups in constructing 2D
kinematic models of the flux transport dynamo. We review both these methods and
conclude that neither of them is fully satisfactory, presumably because
magnetic buoyancy is an inherently 3D process. We also point out so far we do
not have proper understanding of why sunspot emergence is restricted to rather
low latitudes.
