A magnetohydrodynamic model applied to the lower convective region in the Sun

We have investigated the effects of a toroidal-type magnetic field of 10 T (105 G), in the lower convective region of a standard solar model. From the numerical solution of the magnetohydrodynamic (MHD) equations, distributions of some physical variables are obtained in spherical coordinates for this layer. It is shown that the most important feature of this type of magnetic field is to break the spherical symmetric distribution of density and alter its compressibility with respect to latitude. This type of magnetic field does not change much the density of the reference model, and the resulting flux is also comparable to that found in other research. It is further shown that the MHD plasma acts as incompressible at the poles, in contrast to the perfect fluid behaviour at the equator. As a result we have estimated the limits and applicability of the anelastic and Boussinesq approximations for this layer. Thus our results might be useful, especially in simplifying the numerical integration schemes related to the lower convection zone in the Sun.