An interpretation of the core-mantle interaction problem

Abstract

This paper deals with the canonical formulation of the rotation of a non-rigid earth with a heterogeneous stratified liquid core. The treatment of Kubo (1979) for a rigid core-rigid mantle earth model is extended by considering the core as liquid instead of rigid. We show that the tensional torque introduced by Kubo to explain the core-mantle interaction is due to the hypothesis of rigidity of the core, this interaction now being included in the new expression of the kinetic energy. More precisely, this interaction is due to a kind of variation or deformation of the inertia tensor of the core, which we have named inertial deformation, in correspondence with the inertial coupling of Sasao. Okubo & Saito (1980) and Kubo (1979) among other authors. The Hamiltonian obtained is compared with that of Sevilla & Romero (1987), showing the equivalence between them.