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Astrophysics

, Volume 61, Issue 2, pp 147–159 | Cite as

Torus Dynamo Model for Study of Magnetic Fields in the Outer Rings of Galaxies

  • E. A. Mikhailov
Article
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At present, there is essentially no doubt that magnetic fields of a few μG exist in some spiral galaxies. The fields are produced by a dynamo mechanism. Because the equations of the dynamo theory are quite complicated, a two-dimensional approximation is often used since the galactic disk is sufficiently thin, so it is possible to replace some partial derivatives with algebraic expressions. Some galaxies have outer rings in which magnetic fields may also exist. The generation of these fields can also be studied using a two-dimensional approximation, but because that approximation was not developed for rings, but for thin disks, in this case it only yields qualitative results. Therefore, a torus dynamo model is used to study this process. This model is used to analyze possible scenarios for the evolution of magnetic fields in outer rings. It is found that for motions that are not too intense, a field with a quadrupole symmetry is generated. For faster motions a dipole component of the field may develop, which is fundamentally impossible in the two-dimensional approximation.

Keywords

outer rings of galaxies: dynamo theory 

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References

  1. 1.
    R. Beck, A. Brandenburg, D. Moss, et al., Ann. Rev. Astron. Astrophys. 34, 155 (1996).ADSCrossRefGoogle Scholar
  2. 2.
    R. Beck, J. Anderson, G. Heald, et al., Astron. Nachr. 334, 548 (2013).Google Scholar
  3. 3.
    C. van Eck and J.-A. Brown, 11th Annual Meeting of the Northwest Section of APS, May 14-16, B1.005 (2009).Google Scholar
  4. 4.
    M. Haverkorn, P. Katgert, and A. G. de Bruyn, Astron. Astrophys. 427, 169 (2004).ADSCrossRefGoogle Scholar
  5. 5.
    R. Stepanov, R. Beck, T. Arshakian, et al., Astron. Astrophys. 480, 45 (2008).ADSCrossRefGoogle Scholar
  6. 6.
    T. Arshakian, R. Beck, M. Krause, and D. Sokoloff, Astron. Astrophys. 494, 21 (2009).ADSCrossRefGoogle Scholar
  7. 7.
    H. K. Moffatt, Magnetic Field Generation in Conducting Fluids [Russian translation], Mir, Moscow (1980).Google Scholar
  8. 8.
    F. Krause and K.-H. Rädler, Mean-Field Magnetohydrodynamics and Dynamo Theory [Russian translation], Mir, Moscow (1984).Google Scholar
  9. 9.
    K. Subramanian and L. Mestel, Mon. Not. Roy. Astron. Soc. 265, 649 (1993).ADSCrossRefGoogle Scholar
  10. 10.
    D. Moss, Mon. Not. Roy. Astron. Soc. 275 (191 (1995).Google Scholar
  11. 11.
    A. Phillips, Geophys. Astrophys. Fluid Dyn. 94, 135 (2001).ADSCrossRefGoogle Scholar
  12. 12.
    D. Moss and D. Sokoloff, Astron. Nachr. 332, 88 (2011).ADSCrossRefGoogle Scholar
  13. 13.
    E. A. Mikhailov, Pis’ma v Astron. zh. 39, 474 (2013).Google Scholar
  14. 14.
    J. C. Theys and E. A. Spiegel, Astrophys. J. 208, 650 (1976).ADSCrossRefGoogle Scholar
  15. 15.
    D. Moss, E. Mikhailov, O. Sil’chenko, et al., Astron. Astrophys. 592, A44 (2016).CrossRefGoogle Scholar
  16. 16.
    W. Deinzer, H. Grosser, and D. Schmitt, Astron. Astrophys. 273, 405 (1993).ADSGoogle Scholar
  17. 17.
    J. M. Brooke and D. Moss, Mon. Not. Roy. Astron. Soc. 266, 733 (1994).ADSCrossRefGoogle Scholar
  18. 18.
    J. M. Brooke and D. Moss, Astron. Astrophys. 303, 307 (1995).ADSGoogle Scholar
  19. 19.
    E. A. Mikhailov, Astron. zh. 94, 741 (2017).Google Scholar
  20. 20.
    E. Mikhailov, A. Kasparova, D. Moss, et al., Astron. Astrophys. 568, A66 (2014).CrossRefGoogle Scholar
  21. 21.
    E. A. Mikhailov, Vestnik Mosk. un-ta. Ser 3. Fiz. Astron. 2, 27 (2015).Google Scholar
  22. 22.
    D. Moss, A. Shukurov, and D. Sokoloff, Geophys. Astrophys. Fluid Dyn. 89, 285 (1998).ADSCrossRefGoogle Scholar
  23. 23.
    L. Mestel, K. Subramanian, Mon. Not. Roy. Astron. Soc. 248, 677 (1991).ADSCrossRefGoogle Scholar

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© Springer Science+Business Media, LLC, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Physics FacultyM. V. Lomonosov Moscow State UniversityMoscowRussia

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