The Stewartson layer under the influence of the Lorentz and Archimedean forces

The influence of the Lorentz force on the Stewartson layer evolving at the rotating inner core is investigated for the case when its nonlinear effects are not ignored. The influence of the imposed Archimedean force is also examined. The problem is solved using a finite difference method for the basic physical variables of velocity, magnetic field, and pressure. The pressure variable is subsequently corrected by a fractional step method. When only viscous forces are assumed at the inner core boundary, no differences with the previous results are found. However, when the influence of the Lorentz force is considered and all its nonlinear effects are taken into account, the superrotation of the outer core exhibits a different character and a larger amplitude than in the case when the nonlinear effects are ignored. The Archimedean force distinctly increases the Stewartson layer width and thus the change in the azimuthal velocity at the inner core boundary is not as sharp.