β Plane MHD turbulence and dissipation in the solar tachocline

Patrick H. Diamond, Sanae I. Itoh, Kimitaka Itoh, Lara J. Silvers

Research output: Chapter in Book/Report/Conference proceedingChapter

13 Citations (Scopus)

Abstract

The physical processes causing the turbulent dissipation and mixing of momentum and magnetic fields in the solar tachocline are discussed in the context of a simple model of two-dimensional MHD turbulence on a ß-plane. The mean turbulent resistivity and viscosity for this model are calculated. Special attention is given to the enhanced dynamical memory induced by small scale magnetic fields and to the effects of magnetic fluctuations on nonlinear energy transfer. The analogue of the Rhines scale for ß-plane MHD is identified. The implications of the results for models of the solar tachocline structure are discussed. Introduction The tachocline is a thin, stably stratified layer of the solar interior situated in the radiative zone, immediately below the convection zone (Miesch 2005;Tobias 2005). This layer connects the latitudinal differential rotation of the solar convection zone to the expected solid body rotation of the solar interior (Schou et al. 1998; see also Chapter 3 in this book by Christensen-Dalsgaard & Thompson). Thus, flows in the tachocline are sheared (both poloidally and radially), with the predominant structure being that of a radially sheared toroidal flow. The stratification of the tachocline is strongly stable (with Richardson number Ri » 1), and the magnetic field strength is significant, though magnetic pressure is still much smaller than thermal pressure, consistent with hydrostatic equilibrium, i.e.

Original languageEnglish
Title of host publicationThe Solar Tachocline
PublisherCambridge University Press
Pages213-240
Number of pages28
Volume9780521861014
ISBN (Electronic)9780511536243
ISBN (Print)0521861012, 9780521861014
DOIs
Publication statusPublished - Jan 1 2007

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

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    Diamond, P. H., Itoh, S. I., Itoh, K., & Silvers, L. J. (2007). β Plane MHD turbulence and dissipation in the solar tachocline. In The Solar Tachocline (Vol. 9780521861014, pp. 213-240). Cambridge University Press. https://doi.org/10.1017/CBO9780511536243.010