2012/12/04 by Mikael Beuthe
Biochemistry, Genetics and Molecular Biology · Earth and Planetary Sciences · Physics and Astronomy · #Astro and Planetary Science #Classical mechanics #Convection #Dissipation #Geology #Geomagnetism and Paleomagnetism Studies #Geophysics #High-pressure geophysics and materials #Inner core #Internal heating #Lithosphere #Mantle (geology) #Mantle convection #Mechanics #Physics #Planet #Thermodynamics #Tidal acceleration #Tidal heating #physics.geo-ph #physics.space-ph
paper · pdf · doi:10.1016/j.icarus.2012.11.020
published as Icarus 223 (2013) 308-329 · 51 pages, 8 figures, accepted for publication in Icarus
openalex publication_date 2012/12/04 · arxiv created 2012/12/19 · arxiv updated 2013/02/12 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
In a body periodically strained by tides, heating produced by viscous friction is far from homogeneous. I show here that the distribution of the dissipated power within a spherically stratified body is a linear combination of three angular functions. These angular functions depend only on the tidal potential whereas the radial weights are specified by the internal structure of the body. The 3D problem of predicting spatial patterns of dissipation at all radii is thus reduced to the 1D problem of computing weight functions. I compute spatial patterns in various toy models without assuming a specific rheology: a viscoelastic thin shell stratified in conductive and convective layers, an incompressible homogeneous body and a two-layer model of uniform density with a liquid or rigid core. For a body in synchronous rotation undergoing eccentricity tides, dissipation in a mantle surrounding a liquid core is highest at the poles. Within a softer layer (asthenosphere or icy layer), the same tides generate maximum heating in the equatorial region with a significant degree-four structure if the layer is thin. Tidal heating patterns are thus of three main types: mantle dissipation (including the case of a floating icy crust), dissipation in a thin soft layer and dissipation in a thick soft layer. I illustrate the method with applications to Europa, Titan and Io. The formalism described in this paper applies to dissipation within solid layers of planets and satellites for which internal spherical symmetry and viscoelastic linear rheology are good approximations.