Waves in the core and mechanical core-mantle interactions

D. Jault, Chris Finlay

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Abstract

This Chapter focuses on time-dependent uid motions in the core interior, which can beconstrained by observations of the Earth's magnetic eld, on timescales which are shortcompared to the magnetic diusion time. This dynamics is strongly inuenced by the Earth's rapid rotation, which rigidies the motions in the direction parallel to the Earth'srotation axis. This property accounts for the signicance of the core-mantle topography.In addition, the stiening of the uid in the direction parallel to the rotation axis gives riseto a magnetic diusion layer attached to the core-mantle boundary, which would otherwisebe dispersed by Alfven waves. This Chapter complements the descriptions of large-scaleow in the core (8.04), of turbulence in the core (8.06) and of core-mantle interactions(8.12), which can all be found in this volume. We rely on basic magnetohydrodynamictheory, including the derivation of the induction equation from Ohm's law and Maxwellequations, as presented in Chapter (8.03).
Original languageEnglish
Title of host publicationTreatise on Geophysics : Core Dynamics
Editors Gerald Schubert
Volume8
PublisherElsevier
Publication date2015
Edition2.
Pages225-245
Chapter9
ISBN (Print)978-0444538024
DOIs
Publication statusPublished - 2015

Keywords

  • Earth's core
  • Core-mantle topography
  • Torsional waves
  • Rossby waves
  • Quasi-geostrophy

Cite this

Jault, D., & Finlay, C. (2015). Waves in the core and mechanical core-mantle interactions. In G. Schubert (Ed.), Treatise on Geophysics: Core Dynamics (2. ed., Vol. 8, pp. 225-245). Elsevier. https://doi.org/10.1016/B978-0-444-53802-4.00150-0