Dissipation at the core-mantle boundary on a small-scale topography

• Published in: Journal of Geophysical Research Vol. 111; no. B4; pp. B04413 - n/a
• Main Authors: Le Mouël, J. L., Narteau, C., Greff‐Lefftz, M., Holschneider, M.
• Format: Journal Article
• Language: English
• Published: Washington, DC American Geophysical Union 01-04-2006; Blackwell Publishing Ltd
• Subjects: Boundaries; Core processes; Core-mantle boundary; core-mantle coupling; Dissipation; Earth rotation variations; Earth Sciences; Earth, ocean, space; Exact sciences and technology; Fluid dynamics; Fluid flow; Fluid Planets; Fluids; Friction; Geodesy and Gravity; Geomagnetism and Paleomagnetism; nutations; Orbital and rotational dynamics; Planetary Sciences; Sciences of the Universe; Tidal forces; Topography; nutations; core-mantle coupling; friction; drill cores; nutation; interfaces; inner core boundary; roughness; Cosmic background radiation; topography; accuracy; core-mantle boundary; theory; Electromagnetic coupling
• ISSN: 0148-0227; 2169-9313; 2156-2202; 2169-9356
• DOI: 10.1029/2005JB003846

The parameters of the nutations are now known with a good accuracy, and the theory accounts for most of their values. Dissipative friction at the core‐mantle boundary (CMB) and at the inner core boundary is an important ingredient of the theory. Up to now, viscous coupling at a smooth interface and electromagnetic coupling have been considered. In some cases they appear hardly strong enough to account for the observations. We advocate here that the CMB has a small‐scale roughness and estimate the dissipation resulting from the interaction of the fluid core motion with this topography. We conclude that it might be significant.