Hostname: page-component-78c5997874-lj6df Total loading time: 0 Render date: 2024-11-05T21:41:22.200Z Has data issue: false hasContentIssue false
  • English
  • Français

Near-surface shear layer dynamics

Published online by Cambridge University Press:  01 August 2006

Axel Brandenburg
Axel Brandenburg*
Affiliation:
Nordita, Blegdamsvej 17, DK-2100 Copenhagen Ø, Denmark and AlbaNova University Center, SE – 106 91 Stockholm, Sweden email: [email protected]
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

The outer surface layers of the sun show a clear deceleration at low latitudes. This is generally thought to be the result of a strong dominance of vertical turbulent motions associated with strong downdrafts. This strong negative radial shear should not only contribute to amplifying the toroidal field locally and to expelling magnetic helicity, but it may also be responsible for producing a strong prograde pattern speed in the supergranulation layer. Using simulations of rotating stratified convection in cartesian boxes located at low latitudes around the equator it is shown that in the surface layers patterns move in the prograde direction on top of a retrograde mean background flow. These patterns may also be associated with magnetic tracers and even sunspot proper motions that are known to be prograde relative to the much slower surface plasma.

Keywords

ConvectionhydrodynamicsinstabilitiesMHDturbulencewavesSun: activitygranulationhelioseismologymagnetic fieldsrotation
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 2 , Symposium S239: Convection in Astrophysics , August 2006 , pp. 457 - 466
Copyright
Copyright © International Astronomical Union 2007

References

Brandenburg, A. 2005, ApJ, 625, 539CrossRefGoogle Scholar
Brandenburg, A., Jennings, R. L., Nordlund, Å., Rieutord, M., Stein, R. F., & Tuominen, I. 1996, J. Fluid Mech., 306, 325CrossRefGoogle Scholar
Brandenburg, A., Chan, K. L., Nordlund, Å., & Stein, R. F. 2005, Astron. Nachr., 326, 681CrossRefGoogle Scholar
Busse, F. H. 2004, Chaos, 14, 803CrossRefGoogle Scholar
Chan, K. L. 2001, ApJ, 548, 1102CrossRefGoogle Scholar
Dobler, W., Stix, M., & Brandenburg, A. 2006, ApJ, 638, 336CrossRefGoogle Scholar
Dorch, S. B. F. & Nordlund, Å. 2001, A&A, 365, 562Google Scholar
Duvall, T. L., Dziembowski, W. A., Goode, P. R., Gough, D., Harvey, J. W., & Leibacher, J. W. 1984, Nature, 310, 22CrossRefGoogle Scholar
Gilman, P. A., & Foukal, P. V. 1979, ApJ, 229, 1179CrossRefGoogle Scholar
Gizon, L., Duvall, T. L. Jr, & Schou, J. 2003, Nature, 421, 43CrossRefGoogle Scholar
Golub, L., Rosner, R., Vaiana, G. S., & Weiss, N. O. 1981, ApJ, 243, 309CrossRefGoogle Scholar
Green, C. A., & Kosovichev, A. G. 2006, ApJ, 641, L77CrossRefGoogle Scholar
Hathaway, D. H., Williams, P. E., & Cuntz, M. 2006, ApJ, 644, 598CrossRefGoogle Scholar
Howe, R., Christensen-Dalsgaard, J., Hill, F., et al. 2000, Science, 287, 2456CrossRefGoogle Scholar
Käpylä, P. J., Korpi, M. J., & Tuominen, I. 2004, A&A, 422, 793Google Scholar
Kippenhahn, R. 1963, ApJ, 137, 664CrossRefGoogle Scholar
Kitchatinov, L. L. & Mazur, M. V. 2000, Solar Phys., 191, 325CrossRefGoogle Scholar
Kitchatinov, L. L. & Rüdiger, G. 2005, Astron. Nachr., 326, 379CrossRefGoogle Scholar
Kleeorin, N. I., Mond, M., & Rogachevskii, I. 1996, A&A, 307, 293Google Scholar
Nordlund, Å., Brandenburg, A., Jennings, R. L., Rieutord, M., Ruokolainen, J., Stein, R. F., & Tuominen, I. 1992, ApJ, 392, 647CrossRefGoogle Scholar
Pulkkinen, P., Tuominen, I., Brandenburg, A., Nordlund, Å., & Stein, R. 1993, A&A, 267, 265Google Scholar
Rast, M. P., Lisle, J. P., & Toomre, J. 2004, ApJ, 608, 1156CrossRefGoogle Scholar
Rüdiger, G. 1980, Geophys. Astrophys. Fluid Dyn., 16, 239CrossRefGoogle Scholar
Rüdiger, G. 1989, Differential rotation and stellar convection (Gordon & Breach, New York)CrossRefGoogle Scholar
Rüdiger, G., Küker, M., & Chan, K. L. 2003, A&A, 399, 743Google Scholar
Spiegel, E. A., & Weiss, N. O. 1980, Nature, 287, 616CrossRefGoogle Scholar
Tobias, S. M., Brummell, N. H., Clune, T. L., & Toomre, J. 1998, ApJ, 502, L177 L177CrossRefGoogle Scholar
Tobias, S. M., Brummell, N. H., Clune, T. L., & Toomre, J. 2001, ApJ, 549, 1183CrossRefGoogle Scholar
Thompson, M., Christensen-Dalsgaard, J., Miesch, M., & Toomre, J. 2003, ARA&A, 41, 599Google Scholar
Wasiutynski, J. 1946, Astroph. Norveg., 4, 1Google Scholar