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Solar Magnetoconvection

Published online by Cambridge University Press:  08 February 2017

Å. Nordlund  and
R. F. Stein
Å. Nordlund
Affiliation:
Copenhagen University Observatory ⊘ster Voldgade 3 1350 Copenhagen K Denmark
R. F. Stein
Affiliation:
Dept. of Physics and Astronomy Michigan State University, East Lansing, MI 48823 U.S.A.

Abstract

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As a prelude to discussing the interaction of magnetic fields with convection, we first review some general properties of convection in a stratified medium. Granulation, which is the surface manifestation of the major energy carrying convection scales, is a shallow phenomenon. Below the surface, the topology changes to one of filamentary cool downdrafts, immersed in a gently ascending isentropic background. The granular downflows merge into more widely separated downdrafts, on scales of mesogranulation and super-granulation.

The local topology and time evolution of the small scale, kilo Gauss, network and facular magnetic field elements are controlled by convection on the scale of granulation. The topology and time evolution of larger scale magnetic field concentrations are controlled by the hierarchical structure of the horizontal components of the large scale velocity field. In sunspots, the small scale magnetic field structure determines the energy balance, the systematic flows and the waves. Below the surface, the small scale structure of the magnetic field may change drastically, with little observable effect at the surface. We discuss results of some recent numerical simulations of sunspot magnetic fields, and some mechanisms that may be relevant in determining the topology of the sub-surface magnetic field. Finally, we discuss the role of active region magnetic fields in the global solar dynamo.

Type
IV. Magnetohydrodynamics of the Photosphere
Information
Symposium - International Astronomical Union , Volume 138: Solar Photosphere: Structure, Convection and Magnetic Fields , 1990 , pp. 191 - 211
Copyright
Copyright © Kluwer 1990 

References

Albregtsen, F., Maltby., P., 1978, Nature , 274, 41.Google Scholar
Albregtsen, F., Maltby., P., 1981, Solar Phys. 71, 269.CrossRefGoogle Scholar
Bray, R.J., Loughhead, R.E., Durrant, C.J., 1984, The Solar Granulation , Cambridge University Press.Google Scholar
Deinzer, W., Hensler, G., Schüssler, M., Weisshaar, E., 1984a, Astron. Astrophys. 139, 426.Google Scholar
Deinzer, W., Hensler, G., Schüssler, M., Weisshaar, E., 1984b, Astron. Astrophys. 139, 435.Google Scholar
Gilman, P.A., Miller, J., 1986, Astrophys. J. Suppl. 61, 585 Google Scholar
Glatzmaier, G.A., 1987, in The Solar Internal Angular Velocity: Theory, Observations and Relationships to the Solar Magnetic Fields , eds. Durney, B.R. and Sofia, S., Reidel, Dordrecht, p. 263.CrossRefGoogle Scholar
Grossmann-Doerth, U., Schüssler, M., Solanki, S.K., 1988, Astron. Astrophys. 206, L37.Google Scholar
Hurlburt, N. E., Toomre, J. and Massaguer, J. M. 1984, Astrophys. J. 282, 557.CrossRefGoogle Scholar
Jahn, K., 1989, Astron. Astrophys. (in press).Google Scholar
Knölker, M., Schüssler, M., Weisshaar, E., 1988, Astron. Astrophys. 194, 257.Google Scholar
Leighton, R.B., Noyes, R.W., and Simon, G.W., 1962, Astrophys. J. 135, 474.Google Scholar
Libbrecht, K.G., 1988, Proc. Symp. Seismology of the Sun and Sun-like Stars, Tenerif, Spain, 26-30 September 1988 , ESA SP-286, p. 131.Google Scholar
Lites, B.W., Nordlund, Å., and Scharmer, G.B. 1989, in Proceedings NATO Advanced workshop on Solar and Stellar Granulation , eds. Rutten, R.J. and Severino, G., Kluwer Academic Publishers, Dordrecht, p. 349.Google Scholar
Maltby, P., Avrett, E.H., Carlsson, M., Kjeldseth-Moe, O., Kurucz, R.L., Loeser, R., 1986, Astrophys. J. 306, 284.CrossRefGoogle Scholar
Müller, R., 1989, in Proceedings NATO Advanced workshop on Solar and Stellar Granulation , eds. Rutten, R.J. and Severino, G., Kluwer Academic Publishers, Dordrecht, p. 9.Google Scholar
Nordlund, Å., 1982, Astron. Astrophys. 107, 1.Google Scholar
Nordlund, Å, 1983, in “Solar and Stellar Magnetic Fields: Origin and Coronal Effects”, ed. Stenflo, J.-O., IAU Symp. 102, 79.Google Scholar
Nordlund, Å, 1984a, in Small Scale Processes in Quiet Stellar Atmospheres , ed. Keil, S.L., Sacramento Peak Observatory, Sunspot, N.M. 88349, p. 174.Google Scholar
Nordlund, Å, 1984b, in Small Scale Processes in Quiet Stellar Atmospheres , ed. Keil, S.L., Sacramento Peak Observatory, Sunspot, N.M. 88349, p. 181.Google Scholar
Nordlund, Å, 1984c, in The Hydromagnetics of the Sun, Proc. 4th European Meeting in Solar Physics , ESA SP-220, p. 37.Google Scholar
Nordlund, Å, 1985a, Solar Phys. 100, 209.Google Scholar
Nordlund, Å, 1985a, in Problems in Stellar Spectral Line Formation Theory , eds. Beckman, J.O. and Crivellari, L., Reidel, Dordrecht, p. 215.Google Scholar
Nordlund, Å, 1985c, in Proc. MPA/LPARL Workshop on Theoretical Problems in Solar Physics , MPA 212, p. 1.Google Scholar
Nordlund, Å, 1985d, in Proc. MPA/LPARL Workshop on Theoretical Problems in Solar Physics , MPA 212, p. 101.Google Scholar
Nordlund, Å, 1986, Abh. der Akad. der Wissensch. in Göttingen , 38, 83.Google Scholar
Nordlund, Å, 1989, (in preparation).Google Scholar
Nordlund, Å. and Dravins, D., 1989, Astron. Astrophys. (in press).Google Scholar
Nordlund, Å., Stein, R.F., 1989a, Proceedings NATO Advanced workshop on Solar and Stellar Granulation , eds. Rutten, R.J. and Severino, G., Kluwer Academic Publishers, Dordrecht, p. 453.Google Scholar
November, L.J., Toomre, J, and Gebbie, K.B., 1981, Astrophys. J. 245, L123.Google Scholar
November, L.J., Simon, G.W., 1988, Astrophys. J. 333, 427.CrossRefGoogle Scholar
Scherrer, P.H., Hoeksema, J.T., Bogart, R.S., Walker, A.B.C. Jr., Title, A.M., Tarbell, T.D., Wolfson, C.J., Brown, T.M., Christensen-Dalsgaard, J., Gough, D.O., Kuhn, J.R., Leibacher, J.W., Libbrecht, K.G., Noyes, R.W., Rhodes, E.J. Jr., Toomre, J., Zweibel, E.G., Ulrich, R.K. Jr., 1989, ESA SP-1104, p. 25.Google Scholar
Schrijver, C.J., 1989, Solar Phys. (in press).Google Scholar
Simon, G.W., and Leighton, R.B., 1964, Astrophys. J. 140, 1120.Google Scholar
Simon, G.W., Title, A.M., Topka, K.P., Tarbell, T.D., Shine, R.A., Ferguson, S.H., Zirin, H., and the Soup team, 1988, Astrophys. J. 327, 964.Google Scholar
Snodgrass, H.B., 1983, Astrophys. J. 270, 288.Google Scholar
Solanki, S.K., Stenflo, J.O., 1984, Astron. Astrophys. 140, 185.Google Scholar
Solanki, S.K., Stenflo, J.O., 1985, Astron. Astrophys. 148, 123.Google Scholar
Spruit, H.C., 1976, Solar Phys. 50, 269.Google Scholar
Spruit, H.C., Zwaan, C., 1981, Solar Phys. 70, 207.Google Scholar
Stenflo, J.O., 1975, Solar Phys. 42, 79.Google Scholar
Stenflo, J.O., 1989a, Astron. Astrophys. 210, 403.Google Scholar
Stenflo, J.O., 1989b, Astron. Astrophys. Review 1, 3.CrossRefGoogle Scholar
Stenflo, J.O., Solanki, S.K., Harvey, J.W., 1987, Astron. Astrophys. 171, 305. Stein, R.F. and Nordlund, A, 1989, Astrophys. J. (Letters) 342, L95.Google Scholar
Title, A.M., Tarbell, T.D., Topka, K.P., Ferguson, S.H., Shine, R.A., and the SOUP team, 1989, Astrophys. J. 336, 475.Google Scholar
van Ballegooijen, A.A., 1982, Astron. Astrophys. 106, 43.Google Scholar
Wang, H., 1989, Solar Phys. (in press).Google Scholar
Zirin, H., 1987, Solar Phys. 114, 239.Google Scholar