Topographic core‐mantle coupling results from pressure gradients across bumps at the CMB. Hide (1969, 1977) initiated the study of this mechanism. He discussed how pressure lows and highs result from fluid motions below the core surface. Later, dynamic pressure at the core surface (
from peak to trough) has been estimated from geomagnetic secular variation models through core flow modeling. Subsequent research was focused on the strength of the pressure torque by comparison with electromagnetic, viscous, and gravitational torques acting either at the CMB or at the ICB. These research works have often been controversial because of our poor knowledge of the relief at the core‐mantle interface (see Core‐mantle coupling topography, seismology ) and of the motions at the core surface. The axial pressure torque acting on the mantle is:
where k is the unit vector along the rotation axis, n is the normal outward to the fluid volume, r is the position vector, and pis the pressure. It would...
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Jault, D. (2007). Core‐Mantle Coupling, Topographic. In: Gubbins, D., Herrero-Bervera, E. (eds) Encyclopedia of Geomagnetism and Paleomagnetism. Springer, Dordrecht. https://doi.org/10.1007/978-1-4020-4423-6_54
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