Model calculations concerning rotation at high solar latitudes and the depth of the solar convection zone

Abstract

view Abstract Citations (54) References (19) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Model calculations concerning rotation at high solar latitudes and the depth of the solar convection zone. Gilman, P. A. Abstract The author has previously carried out extensive nonlinear numerical simulations of convection in a rotating spherical shell, motivated by the problem of understanding the Sun's differential rotation. The polar vortex found in earlier calculations, but not observed on the Sun, disappears when shell depths as large as 40% of the radius are assumed. The equatorial acceleration is also enhanced, producing a closer fit to solar observations than previous calculations for depths of 20%. The reasons for the disappearance of the polar vortex are that in deeper layers the Reynolds stresses, which transport angular momentum toward the equator to form the equatorial acceleration, reach to higher latitudes, and the moment of inertia of the polar cap region is a smaller fraction of the total for the shell. Although the model used is for a stratified liquid (the Boussinesq approximation), we argue that deep layers are less likely to have a polar vortex than shallow ones in the compressible case too. This result favors a solar convection zone substantially deeper than previously inferred from stellar structure calculations applied to the Sun, but is consistent with recent inferences of a deep convection zone made from measurements of solar oscillations. Subject headings: convection - Sun: interior - Sun: rotation Publication: The Astrophysical Journal Pub Date: July 1979 DOI: 10.1086/157191 Bibcode: 1979ApJ...231..284G Keywords: Computerized Simulation; Convection; Polar Regions; Solar Rotation; Reynolds Stress; Solar Oscillations; Vortices; Solar Physics; Convection:Solar Interior; Solar Rotation full text sources ADS | Related Materials (1) Erratum: 1980ApJ...236..706G