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The Solar Dynamo

  • D. Schmitt (a1)

Abstract

The generation of the solar magnetic field is generally ascribed to dynamo processes in the convection zone. The dynamo effects, differential rotation (ω–effect) and helical turbulence (α–effect) are explained, and the basic properties of the mean–field dynamo equations are discussed in close comparison with the observed solar cycle.

Especially the question of the seat of the dynamo is addressed. Problems of a dynamo in the convection zone proper could be magnetic buoyancy, the nearly strict observance of the polarity rules and the migration pattern of the magnetic fields which are difficult to understand in the light of recent studies of the field structure in the convection zone and by observations of the solar acoustic oscillations. To overcome some of these problems it has been suggested that the solar dynamo operates in the thin overshoot region at the base of the convection zone instead. Some aspects of such an interface dynamo are discussed. As an alternative to the turbulent α–effect a dynamic α-effect based on magnetostrophic waves driven by a magnetic buoyancy instability of a magnetic flux layer is introduced. Model calculations for both pictures, a convection zone and an interface dynamo, are presented which use the internal rotation of the sun as deduced from helioseismology. Solutions with solar cycle behaviour are only obtained if the magnetic flux is bounded in the lower convection zone and the α–effect is concentrated near the equator.

Another aspect briefly addressed is the nonlinear saturation of the magnetic field. The necessity of the dynamic nature of the dynamo processes is emphasized, and different processes, e.g. magnetic buoyancy and α-quenching, are mentioned.

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References

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Acheson, D.J.: 1978, Phil. Trans. Roy. Soc. A289, 459
Acheson, D.J.: 1979, Solar Phys. 62, 23
Acheson, D.J. & Hide, R.: 1973, Rep. Prog. Phys. 36, 159
Acheson, D.J. & Gibbons, M.P.: 1978, J. Fluid Mech. 85, 743
Belvedere, G., Pitadella, R.M. & Proctor, M.R.E.: 1990, Geophys. Astrophys. Fluid Dyn. 51, 263
Brandenburg, A. & Tuominen, I.: 1990, ‘The Solar Dynamo’, in The Sun and Cool Stars: activity, magnetism, dynamos , Tuominen, I., Moss, D. & Rüdiger, G. (eds.), IAU-Coll. 130, Lecture Notes in Physics 380, 223
Brandenburg, A., Krause, F., Meinel, R., Moss, D. & Tuominen, I.: 1989, Astron. Astrophys. 213, 411
Brandenburg, A., Nordlund, Å., Pulkinnen, P., Stein, R.F. & Tuominen, I.: 1990, Astron. Astrophys. 232, 277
Brandenburg, A., Moss, D., Rüdiger, G. & Tuominen, I.: 1991, Geophys. Astrophys. Fluid Dyn. 61, 179
Brandenburg, A., Moss, D. & Tuominen, I.: 1992, ‘Stratification and thermodynamics in mean–field dynamos’, preprint
Brandenburg, A., Moss, D. & Tuominen, I.: 1992, ‘Turbulent pumping in the solar dynamo’, in NSO/Sacramento Peak 12th Summer Workshop , Harvey, K.L. (ed.), Astron. Soc. Pacific Conf. Proc.
Brown, T.M., Morrow, C.A.: 1987, Astrophys. J. 314, L21
Brown, T.M., Christensen–Dalsgaard, J., Dziembowski, W.A., Goode, P., Gough, D.O. & Morrow, C.A.: 1989, Astrophys. J. 343, 526
Choudhuri, A.R.: 1990, Astrophys. J. 355, 733
Choudhuri, A.R.: 1992, Astron. Astrophys. 253, 277
DeLuca, E.E. & Gilman, P.A.: 1986, Geophys. Astrophys. Fluid Dyn. 37, 85
DeLuca, E.E. & Gilman, P.A.: 1988, Geophys. Astrophys. Fluid Dyn. 43, 119
DeLuca, E.E. & Gilman, P.A.: 1991, ‘The Solar Dynamo’, in The Solar Atmosphere and Interior , Cox, A.N. (ed.), Univ. of Arizona Press, Tucson
DeVore, C.R. & Sheeley, N.R. Jr.: 1987, Solar Phys. 108, 47
Drobyshevski, E.M. & Yuferev, V.S.: 1974, J. Fluid Mech. 65, 33
Durney, B.R., DeYoung, D.S. & Roxburgh, I.W.: 1993, ‘On the generation of the large–scale and turbulent magnetic fields in solar–type stars’, Solar Phys. , in press
Dziembowksi, W.A., Goode, P.R. & Libbrecht, K.G.: 1989, Astrophys. J. 337, L53
Elstner, D. & Rüdiger, G.: 1993, ‘Stellar dynamos with anisotropic α-tensor’, this volume
Fearn, D.R. & Proctor, M.R.E.: 1984, Phys. Earth Planet. Inter. 36, 78
Fearn, D.R. & Proctor, M.R.E.: 1987, J. Fluid Mech. 178, 521
Ferrière, K.: 1992, ‘The Full Alpha–Tensor Due to Supernova Explosions and Superbubbles in the Galactic Disk’, preprint
Ferriz–Mas, A., Schüssler, M.: 1992, ‘Instabilites of magnetic flux tubes in a stellar convection zone. I: Toroidal flux tubes in differentially roatating stars’, preprint
Galloway, D.J. & Weiss, N.O.: 1981, Astrophys. J. 243, 945
Gilman, P.A.: 1983, Astrophys. J. Suppl. 53, 243
Gilman, P.A., Miller, J.: 1981, Astrophys. J. Suppl. 46, 211
Gilman, P.A., Miller, J.: 1986, Astrophys. J. Suppl. 61, 585
Gilman, P.A., Morrow, C.A. & DeLuca, E.E.: 1989, Astrophys. J. 338, 528
Glatzmaier, G.A.: 1984, J. Comp. Phys. 55, 461
Glatzmaier, G.A.: 1985a, Astrophys. J. 291, 300
Glatzmaier, G.A.: 1985b, Geophys. Astrophys. Fluid Dyn. 31, 137
Gokhale, M.H. & Javaraiah, J.: 1990, Mon. Not. Royal Astron. Soc. 243, 241
Gokhale, M.H. & Javaraiah, J.: 1992, Solar Phys. 138, 399
Gokhale, M.H., Javaraiah, J. & Hiremath, K.M.: 1990, in Solar Photosphere: Structure, Convection and Magnetic Fields , Stenflo, J.O. (ed.), IAU–Symp. 138, 375
Gokhale, M.H., Javaraiah, J., Kutty, K. Narayanan & Varghese, B.A.: 1992, Solar Phys. 138, 35
Golub, L., Rosner, R., Vaiana, G.S. & Weiss, N.O.: 1981, Astrophys. J. 243, 309
Hellmich, R.: 1978, Geophys. Astrophys. Fluid Dyn. 10, 89
Hinata, S.: 1982, Astrophys. J. 256, L23
Howard, R.F. & LaBonte, B.J.: 1980, Astrophys. J. 239, L33
Howard, R.F. & LaBonte, B.J.: 1991, Solar Phys. 74, 131
Hoyng, P.: 1987, Astron. Astrophys. 171, 348 and 357
Hoyng, P.: 1988, Astrophys. J. 332, 857
Hoyng, P.: 1990, ‘Excitation of Dynamo Waves’, in Solar Photosphere: Structure, Convection and Magnetic Fields , Stenflo, J.O. (ed.), IAU-Symp. 138, 359
Hughes, D.W.: 1991, ‘Magnetic Buoyancy’, in Advances in Solar System Magnetohydrodynamics , Priest, E.R. & Wood, A.W. (eds.), Cambridge University Press, p. 77
Jennings, R.L. & Weiss, N.O.: 1991, Mon. Not. R. Astr. Soc. 252, 249
Kichatinov, L.L.: 1991, Astron. Astrophys. 243, 483
Köhler, H.: 1973, Astron. Astrophys. 25, 467
Krause, F. & Rädler, K.–H.: 1980, Mean–Field Magnetohydrodynmics and Dynamo Theory , Pergamon Press, Oxford
Kurths, J., Feudel, U. & Brandenburg, A.: 1993, ‘Inhomogeneous chaos in nonlinear dynamo models’, this volume
Leighton, R.B.: 1969, Astrophys. J. 156, 1
Leroy, J.–L. & Noens, J.–C.: 1983, Astron. Astrophys. 120, L1
Libbrecht, K.G.: 1988, ‘Solar p–mode frequency split tings’, in Seismology of the Sun and Sun–Like Stars , Rolfe, E.J. (ed.), ESA SP–286, p. 131
Makarov, V.I. & Makarova, V.V.: 1986, J. Astrophys. Astron. 7, 113
Malkus, W.V.R. & Proctor, M.R.E.: 1975, J. Fluid Mech. 67, 417
Meinel, R. & Brandenburg, A.: 1990, Astron. Astrophys. 238, 369
Moffatt, H.K.: 1978, Magnetic Field Generation in Electrically Conducting Fluids , Cambridge University Press
Moreno–Insertis, F.: 1983, Astron. Astrophys. 122, 241
Moreno–Insertis, F.: 1986, Astron. Astrophys. 166, 291
Moreno–Insertis, F., Ferriz–Mas, A. & Schüssler, M.: 1992, ‘Storage of magnetic flux tubes in a convective overshoot region’, Astron. Astrophys. , in press
Moss, D., Brandenburg, A., Tavakol, R. & Tuominen, I.: 1992, ‘Stochastic effects in mean field dynamos’, preprint
Moss, D., Tuominen, I. & Brandenburg, A.: 1990a, Astron. Astrophys. 228, 284
Moss, D., Tuominen, I. & Brandenburg, A.: 1990b, Astron. Astrophys. 240, 142
Parker, E.N.: 1955, Astrophys. J. 122, 293
Parker, E.N.: 1975, Astrophys. J. 198, 205
Parker, E.N.: 1979, Cosmical Magnetic Fields , Clarendon Press, Oxford
Pitadella, R.M. & Stix, M.: 1986, Astron. Astrophys. 157, 338
Prautzsch, T.: 1990, ‘Der Einfluß von breitenabhängigen Induktionseffekten auf einen eindimensionalen sphärischen αω–Dynamo’, Diplomarbeit, Universität Göttingen
Prautzsch, T.: 1993, ‘The Dynamo Mechanism in the Deep Convection Zone of the Sun’, in NATO ASI Theory of Solar and Planetary Dynamos , Proceedings of the Isaac Newton Institute, Cambridge
Prautzsch, T., Schmitt, D. & Schüssler, M: 1993, ‘Non-linear dynamos. II. Two-dimensional model of an overshoot layer dynamo’, in preparation
Proctor, M.R.E.: 1977, J. Fluid Mech. 80, 769
Proctor, M.R.E. & Weiss, N.O.: 1982, Rep. Prog. Phys. 45, 1317
Rädler, K.–H.: 1968, Zs. Naturforsch. 23a, 1851
Rädler, K.–H.: 1980, Astron. Nachr. 301, 101
Rädler, K.–H.: 1990, ‘The Solar Dynamo’, in Inside the Sun , Berthomieu, G. & Cribier, M. (eds.), Kluwer, Dordrecht, IAU-Coll 21, 385
Rädler, K.–H., Wiedemann, E., Brandenburg, A., Meinel, R. & Tuominen, I.: 1990, Astron. Astrophys. 239, 413
Robinson, R.D. & Durney, B.R.: 1982, Astron. Astronphys. 108, 322
Rüdiger, G.: 1978, Astron. Nachr. 299, 217
Rüdiger, G.: 1989, Differential Rotation and Stellar Convection , Akademie–Verlag Berlin
Rüdiger, G. & Kichatinov, L.L.: 1990, Astron. Astrophys. 236, 503
Rüdiger, G. & Kichatinov, L.L.: 1992, ‘Alpha–effect and alpha–quenching’, preprint
Rüdiger, G., Tuominen, I., Krause, F. & Virtanen, H.: 1986, Astron. Astrophys. 166, 306
Schmalz, S. & Stix, M.: 1991, Astron. Astrophys. 245, 654
Schmitt, D.: 1984, ‘Dynamo Action of Magnetostrophic Waves’, in The Hydromagnetics of the Sun , Guyenne, T.D., Hunt, J.J. (eds.), ESA SP–220, 223
Schmitt, D.: 1985, ‘Dynamowirkung magnetostrophischer Wellen’, Thesis, Universität Göttingen
Schmitt, D.: 1987, Astron. Astrophys. 174, 281
Schmitt, D. & Schüssler, M.: 1989, Astron. Astrophys. 223, 343
Schmitt, D.: 1993, ‘Inversion approach to the solar dynamo’, in preparation
Schmitt, D.: 1993, ‘The influence of turbulent diamagnetism and topological pumping on an αω–dynamo in the deep convection zone of the sun’, in preparation
Schmitt, J.H.M.M., Rosner, R. & Bohn, H.U.: 1984, Astrophys. J. 282, 316
Schou, J., Christen–Dalsgaard, J. & Thompson, M.J.: 1992, Astrophys. J. 385, L59
Schüssler, M.: 1977, Astron. Astrophys. 56, 439
Schüssler, M.: 1979a, Astron. Astrophys. 71, 79
Schüssler, M.: 1979b, Astron. Astrophys. 72, 348
Schüssler, M.: 1980, Nature 288, 150
Schüssler, M.: 1981, Astron. Astrophys. 94, L17
Schüssler, M.: 1983, ‘Stellar Dynamo Theory’, in Solar and Stellar Magnetic Fields: Origins and Coronal Effects , Stenflo, J.O. (ed.), IAU–Symp. 102, 213
Schüssler, M.: 1984, ‘On the Structure of Magnetic Fields in the Solar Convection Zone’, in The Hydromagnetics of the Sun Guyenne, T.D., Hunt, J.J. (eds.), ESA SP–220, 67
Schüssler, M.: 1987, ‘Magnetic Fields and the Rotation of the Solar Convection Zone’, in The Internal Solar Angular Velocity , Durney, B.R. & Sofia, S. (eds.), Reidel, Dordrecht, p. 303
Schüssler, M.: 1990, ‘Comments on the structure and dynamics of magnetic fields in stellar convection zones’, Habilitationschrift, Universität Göttingen
Schüssler, M., Ferriz-Mas, A. & Schmitt, D.: 1993, ‘An α–effect due to flux tube instabilities in the solar convection zone’, in preparation
Sheeley, N.R., Nash, A.G. & Wang, Y.–M.: 1987, Astrophys. J. 319, 481
Skaley, D. & Stix, M.: 1991, Astron. Astrophys. 241, 227
Spiegel, E.A. & Weiss, N.O.: 1980, Nature 287, 616
Spruit, H.C. & van Ballegooijen, A.A.: 1982, Astron. Astrophys. 106, 58
Steenbeck, M. & Krause, F.: 1969, Astron. Nachr. 291, 49
Steenbeck, M., Krause, F. & Rädler, K.–H.: 1966, Z. Naturforsch. 21a, 369
Stenflo, J.O.: 1973, Solar Phys. 32, 41
Stenflo, J.O.: 1988, Astrophys. Space Sci. 144, 321
Stenflo, J.O. & Güdel, M.: 1988, Astron. Astrophys. 191, 137
Stenflo, J.O. & Vogel, M.: 1986, Nature 319, 285
Stenflo, J.O. & Weisenhorn, A.L.: 1987, Solar Phys. 108, 205
Stix, M.: 1974, Astron. Astrophys. 37, 121
Stix, M.: 1976, Astron. Astrophys. 47, 243
Stix, M.: 1987, ‘On the Origin of Stellar Magnetism’, in Solar and Stellar Physics, Schröter, E.–H. & Schüssler, M. (eds.), Lecture Notes in Physics , 292, 15
Stix, M.: 1991, Geophys. Astrophys. Fluid Dyn. 62, 211
Teuben, L., Hoyng, P. & Schmitt, D.: 1993, ‘Periodicities in the Large–Scale Solar Magnetic Field’, in preparation
Topka, K., Moore, R., LaBonte, B.J. & Howard, R.: 1982, Solar Phys. 79, 231
Tsinganos, K.C.: 1980, Astrophys. J. 239, 746
van Ballegooijen, A.A.: 1982, Astron. Astrophys. 113, 99
van Ballegooijen, A.A.: 1983, Astron. Astrophys. 118, 275
van Ballegooijen, A.A. & Choudhuri, A.R.: 1988, Astrophys. J. 333, 965
Wädler, M., Deinzer, W. & Stix, M.: 1980, J. Fluid Mech. 96, 207
Wang, Y.–M., Sheeley, N.R. & Nash, A.G.: 1991, Astrophys. J. 383, 431
Weiss, N.O.: 1989, ‘Dynamo Processes in Stars’, in Accretion Discs and Magnetic Fields in Astrophysics , Belvedere, G. (ed.), Kluwer, Dordrecht, p. 11
Weiss, N.O.: 1990, Phil. Trans. R. Soc. Lond. A330, 617
Weiss, N.O., Cattaneo, F. & Jones, C.A.: 1984, Geophys. Astrophys. Fluid Dyn. 30, 305
Weisshaar, E.: 1982, Geophys. Astrophys. Fluid Dyn. 21, 285
Yoshimura, H.: 1972, Astrophys. J. 178, 863
Yoshimura, H.: 1975, Astrophys. J. 201, 740
Yoshimura, H.: 1978, Astrophys. J. 220, 692
Yoshimura, H.: 1981, Astrophys. J. 247, 1102
Zel'dovich, Ya.B.: 1956, Sov. Phys. JETP 31, 154

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The Solar Dynamo

  • D. Schmitt (a1)

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