Mean flow generation in the Earth's outer core via weakly nonlinear hydromagnetic waves

Abstract

The Earth's outer core is modelled as thin layer of incompressible, inviscid, perfectly conducting fluid of constant density on a rotating plane in the presence of a variable ambient magnetic field. The fluid is bounded above by a spatially varying rigid lid. The interaction of the weak nonlinearities of the governing equations with the geometry of the model and its ambient magnetic field lead to positive feedback mechanisms for the generation of westward drift via the basic waves and the associated mean flows. The relevance of these results to the real core is discussed.

Key Words:

• Magnetohydrodynamic waves
• rotating fluids
• Earth's core
• westward drift