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Nonlinear Dynamo in a Disk Galaxy

Published online by Cambridge University Press:  19 July 2016

A. Poezd ,
A. Shukurov  and
D.D. Sokoloff
A. Poezd
Affiliation:
Physics Department, Moscow University, Moscow 119899, Russia
A. Shukurov
Affiliation:
Computing Center, Moscow University, Moscow 119899, Russia
D.D. Sokoloff
Affiliation:
Physics Department, Moscow University, Moscow 119899, Russia

Abstract

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A nonlinear thin-disk galactic dynamo model based on α-quenching is proposed. Assuming that the mean helicity depends on the magnetic field strength averaged across the disk, we derive a universal form of nonlinearity in the radial dynamo equation. We discuss the evolution of the regular magnetic field in the Milky Way and the Andromeda Nebula. It is argued that the reversals of the regular magnetic field in the Galaxy are a relic inherited from the structure of the seed field. We also briefly discuss the role of the turbulent diamagnetism and the effects of galactic evolution on the dynamo.

Keywords

Nonlinear galactic dynamosMagnetic field reversalsNonlinear transients
Type
8. Magnetic Fields in Galaxies: Dynamo Theory
Information
Symposium - International Astronomical Union , Volume 157: The Cosmic Dynamo , 1993 , pp. 349 - 353
Copyright
Copyright © Kluwer 1993 

References

Agafonov, G.I., Sokoloff, D.D. and Ruzmaikin, A.A.: 1988, Astron. Zh. USSR 65, 523 Google Scholar
Beck, R.: 1982, Astron. Astrophys. 106, 121 Google Scholar
Beuermann, K., Kanbach, G. and Berkhuijsen, E.M.: 1985, Astron. Astrophys. 153, 17 Google Scholar
Cordes, J.M., Weisberg, J.M. and Boriakoff, V.: 1985, Astrophys. J. 288, 221 CrossRefGoogle Scholar
Dettmar, R.-J.: 1990, Astron. Astrophys. 232, L15 Google Scholar
Dickey, J.M. and Lockman, F.J.: 1990, Ann. Rev. Astron. Astrophys. 28, 215 CrossRefGoogle Scholar
Krasheninnikova, Y., Ruzmaikin, A., Sokoloff, D. and Shukurov, A.: 1990, Geophys. Astrophys. Fluid Dyn. 50, 131 CrossRefGoogle Scholar
Krause, F. and Rädler, K.-H.: 1980, Mean-Field Magnetohydrodynamics and Dynamo Theory , Pergamon Press: Oxford / Akademie-Verlag: Berlin Google Scholar
Kvasz, L., Sokoloff, D. and Shukurov, A.: 1992, Geophys. Astrophys. Fluid Dyn. 65, 231 CrossRefGoogle Scholar
Lockman, F.J.: 1984, Astrophys. J. 283, 390 CrossRefGoogle Scholar
Rand, R.J., Kulkarni, S.R. and Hester, J.J.: 1990, Astrophys. J. Lett. 352, L1 CrossRefGoogle Scholar
Reynolds, R.J.: 1989, Astrophys. J. Lett. 339, L29 CrossRefGoogle Scholar
Ruzmaikin, A.A. and Sokoloff, D.D.: 1977, Astrophys. Space Sci. 52, 365 CrossRefGoogle Scholar
Ruzmaikin, A.A., Shukurov, A.M. and Sokoloff, D.D.: 1988, Magnetic Fields of Galaxies , Kluwer Acad. Publ.: Dordrecht CrossRefGoogle Scholar
Ruzmaikin, A., Shukurov, A., Sokoloff, D. and Beck, R.: 1991, Astron. Astrophys. 230, 284 Google Scholar
Simard-Normandin, M. and Kronberg, P.P.: 1980, Nature 279, 115 CrossRefGoogle Scholar
Sukumar, S. and Allen, R.J.: 1991, Astrophys. J. 382, 100 CrossRefGoogle Scholar
Vallée, J.P.: 1991, Astrophys. J. 366, 450 CrossRefGoogle Scholar
Vallée, J.P., Simard-Normandin, M. and Bignell, R.C.: 1988, Astrophys. J. 331, 321 CrossRefGoogle Scholar
Zeldovich, Ya.B.: 1956, JETP 31, 154 Google Scholar