Thermal-convective instability of a composite rotating stellar atmosphere in the presence of a variable magnetic field, medium permeability and solute gradient

The thermal-convective instability of a composite rotating stellar atmosphere in the presence of a variable horizontal magnetic field is considered to include, separately, the effects of medium permeability and solute gradient. The criteria for monotonic instability in each case have been obtained which generalize the Defouw's criterion derived for thermal-convective instability in the absence of above effects.