  Circulation-dominated solar dynamo models, which employ a helioseismic
rotation profile and a fixed meridional flow, give a good approximation to the
large scale solar magnetic phenomena, such as the 11-year cycle or the so
called Hale's law of polarities. Nevertheless, the larger amplitude of the
radial shear at the high latitudes makes the dynamo to produce a strong
toroidal magnetic field at high latitudes, in contradiction with the
observations of the sunspots (Sporer`s Law). A possible solution was proposed
by Nandy and Choudhur (2002) in which a deep meridional flow can conduct the
magnetic field inside of a stable layer (the radiative core) and then allow
that it erupts just at lower latitudes. We have recently explored this
hypothesis in a different approximation, using the magnetic buoyancy mechanism
proposed by Dikpaty and Charbonneau (1999) and found that a deep meridional
flow pushes the maximum of the toroidal magnetic field towards the solar
equator, but, in contrast to Nandy and Choudhuri (2002), a second zone of
maximum fields remains at the poles (Guerrero and Munoz (2004)). We here review
these results and also discuss a new possible scenario where the tachocline has
an ellipsoidal shape, following early helioseismologic observations Charbonneau
et. al., (1999), and find that the modification of the geometry of the
tachocline can lead to results which are in good agreement with observations
and opens the possibility to explore in more detail, through the dynamo model,
the place where the magnetic field could be really stored.
