EFFECT OF THE MAGNETIC-FIELD AT THE INNER-CORE BOUNDARY ON THE FLOW IN THE EARTHS CORE

In the problem of Geodynamo, boundary conditions for the 'inviscid' pr oblem were obtained on the basis of solutions in the boundary layers. Using these boundary conditions, the hydrodynamic part of the problem in the axisymmetric case was solved analytically. On this basis, a com puter code has been created free of the need to resolve boundary layer s that sharply increases the rate of computational process. Computer s imulations with this code confirmed the conclusion of Hollerbach [Holl erbach, R., 1994. Magnetohydrodynamic Ekman and Stewartson layers in a rotating spherical shell. Proc. R. Sec. London, Ser. A, 444 (1994) pp . 333-346.] (obtained by a different approach) that sufficiently stron g magnetic fields suppress the discontinuity on the Stewartson cylinde r circumscribing the inner core of the Earth and parallel to the axis of the rotation. The boundary conditions for magnetic field show that a concentrated generation of the toroidal field can Occur in the bound ary layer. Such a concentrated generation seems to take place in the G latzmaier and Roberts numerical solution [Glatzmaier G.A., Roberts, P. H., 1995. A three-dimension convective dynamo solution with rotating a nd finitely conducting inner core and mantle. Phys. Earth Planet. Inte r. 91 (1995) pp. 63-76.]. (C) 1998 Published by Elsevier Science B.V.