Nutation Damping from Core-Mantle Boundary Topography
This research investigates how topography at Earth's core-mantle boundary (CMB) damps nutation oscillations caused by tidal forces. Current models attribute this damping to electromagnetic coupling, but this is physically questionable. The authors propose a new mechanism: tidal flows interacting with CMB topography excite internal waves that extract energy and momentum from the flow, leading to pressure drag that accounts for the observed damping.