On Small-Scale Hydromagnetic Flow in the Earth's Core: Motion of a Rigid Cylinder Parallel to Its Axis

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This is an attempt to understand better the dynamics of the small-scale compositionally buoyant flow in the Earth's core which may be responsible for the generation of the Earth's magnetic field by dynamo action, by determining the rise law and the flow structures of a buoyant rigid cylinder rising in a rotating electrically conducting fluid in the presence of a large-scale magnetic field. The problem is linearized by assuming small Rossby and magnetic Reynolds numbers, and the Lorentz force is assumed to be larger than the viscous and Coriolis forces. It is found that the rise speed is larger than one would expect from simple scaling arguments