Solar cycle properties described by simple convection-driven dynamos
  Simple models of magnetic field generation by convection in rotating spherical shells exhibit properties resembling those observed on the sun. The {assumption of the Boussinesq approximation made in these models} prevents a realistic description of the solar cycle, but through a physically motivated change in the boundary condition for the differential rotation the propagation of dynamo waves towards higher latitudes can be reversed at least at low latitudes. 
Radostin D. Simitev and Friedrich H. Busse
astro-ph.SR physics.flu-dyn