Anisotropic momentum transport in the tachocline

Nicolas Leprovost, Eun Jin Kim

Research output: Chapter in Book/Report/Conference proceedingConference proceeding

Abstract

We provide a theory of the tachocline confinement (or anisotropic momentum transport) within an hydrodynamical turbulence model. Starting from the first principle with the physically plausible assumption that turbulence is driven externally (e.g. by plumes penetrating from the convection zone), we derive turbulent (eddy) viscosity in the radial (vertical) and azimuthal (horizontal) directions by incorporating the crucial effects of shearing due to radial and latitudinal differential rotations in the tachocline.We show that, in the case of strong radial turbulence (driven by overshooting plumes from the convection zone), the ratio of the radial to horizontal eddy viscosity is proportional to A-1/3, where A is the strength of the shear due to radial differential rotation. In comparison, in the case of horizontally driven turbulence, this ratio becomes of order -ε2, with negative radial eddy viscosity. Here, ε (≪ 1) is the ratio of the radial to latitudinal shear. The resulting anisotropy in momentum transport could thus be sufficiently strong to operate as a mechanism for the tachocline confinement against spreading.

Original languageEnglish
Title of host publicationProceedings of SOHO-17
Subtitle of host publication10 Years of SOHO and Beyond
Edition617
Publication statusPublished - 1 Jul 2006
Externally publishedYes
EventSOHO-17: 10 Years of SOHO and Beyond - Sicily, Italy
Duration: 7 May 200612 May 2006

Publication series

NameEuropean Space Agency, (Special Publication) ESA SP
Number617
ISSN (Print)0379-6566

Conference

ConferenceSOHO-17: 10 Years of SOHO and Beyond
CountryItaly
CitySicily
Period7/05/0612/05/06

Keywords

  • Sun: interior
  • Sun: rotation
  • Turbulence

ASJC Scopus subject areas

  • Aerospace Engineering
  • Space and Planetary Science

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