Skip to main content

Recent Developments in Magnetic Dynamo Theory

  • Chapter
  • First Online:
Turbulence and Magnetic Fields in Astrophysics

Part of the book series: Lecture Notes in Physics ((LNP,volume 614))

Abstract

Two spectral regimes of magnetic field amplification in magnetohydrodynamic (MHD) flows can be distinguished by the scale on which fields are amplified relative to the primary forcing scale of the turbulence. For field amplification at or below the forcing scale, the amplification can be called a “small-scale dynamo.” For amplification at and above the forcing scale the process can be called a “large-scale dynamo.” Non - local (in wave number) effects play a key role in both the growth of the small-scale field in non-helical turbulence and the growth of large and smallscale fields in helical turbulence. Mean field dynamo (MFD) theory represents a simple semi-analytic way to get a handle on large-scale field amplification in MHD turbulence. Helicity has long been known to be important for large scale, flux generating, externally forced MFDs. The extent to which such MFDs operate “slow” or “fast” (dependent or independent on magnetic Reynolds number) has been controversial, but there has been recent progress. Simulations of α2 dynamos in a periodic box dynamo and their quenching can now be largely understood within a simplified dynamical non-linear paradigm in which the MFD growth equation is supplemented by the total magnetic helicity evolution equation. For α2 dynamos, the large-scale field growth is directly related to the large-scale magnetic helicity growth. Magnetic helicity conservation then implies that growth of the large-scale magnetic helicity induces growth of small-scale magnetic (and current) helicity of the opposite sign, which eventually suppresses the α effect driving the MFD growth. Although the α2 MFD then becomes slow in the long time limit, substantial large-scale field growth proceeds in a kinematic, “fast” phase before non-linear asymptotic quenching of the “slow” phase applies. Ultimately, the MFD emerges as a process that transfers magnetic helicity between small and large scales. How these concepts apply to more general dynamos with shear, and open boundary dynamos is a topic of ongoing research. Some unresolved issues are identified. Overall, the following summarizes the most recent progress in mean-field dynamo theory: For a closed turbulent flow, the non-linear mean field dynamo, is first fast and kinematic, then slow and dynamic, and magnetic helicity transfer makes it so.

This is a preview of subscription content, log in via an institution to check access.

Access this chapter

Chapter
USD 29.95
Price excludes VAT (USA)
  • Available as PDF
  • Read on any device
  • Instant download
  • Own it forever
eBook
USD 84.99
Price excludes VAT (USA)
  • Available as PDF
  • Read on any device
  • Instant download
  • Own it forever
Softcover Book
USD 109.99
Price excludes VAT (USA)
  • Compact, lightweight edition
  • Dispatched in 3 to 5 business days
  • Free shipping worldwide - see info
Hardcover Book
USD 109.99
Price excludes VAT (USA)
  • Durable hardcover edition
  • Dispatched in 3 to 5 business days
  • Free shipping worldwide - see info

Tax calculation will be finalised at checkout

Purchases are for personal use only

Institutional subscriptions

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. A.A. Ruzmaikin, A.M. Shukurov, D.D. Sokoloff, Magnetic Fields of Galaxies, (Kluwer Press, Dodrecht, 1988).

    Google Scholar 

  2. R. Kulsrud, R. Cen, J.P. Ostriker, and D. Ryu, ApJ, 480 481 (1997)

    Article  ADS  Google Scholar 

  3. E. G. Zweibel & C. Heiles, Nature, 385 131 (1997).

    Article  ADS  Google Scholar 

  4. B.D.G. Chandran, S.C. Cowley, & M. Morris, ApJ, 528 723 (2000).

    Article  ADS  Google Scholar 

  5. S.H. Lubow, J.C.B. Papaloizou, J.E. Pringle, MNRAS, 267, 235 (1994).

    ADS  Google Scholar 

  6. A.P. Kazanstev, Sov. Physics. JETP, 26 1031 (1968).

    ADS  Google Scholar 

  7. E.N. Parker, Cosmical Magnetic Fields (Oxford: Clarendon Press, 1979).

    Google Scholar 

  8. Ya. B. Zeldovich, A.A. Ruzmaikin,, and D.D. Sokoloff, Magnetic Fields in Astrophysics, (Gordon and Breach, New York, 1983).

    Google Scholar 

  9. R.M. Kulsrud & S.W. Anderson, Astrophys. J. 396 606 (1992).

    Article  ADS  Google Scholar 

  10. S. Kida, S. Yanase, J. & Mizushima, Physics of Fluids, 3 457 (1991)

    Article  ADS  Google Scholar 

  11. J. Maron & S. Cowley, to be submitted to ApJ (2002); http://xxx.lanl.gov/abs/astro-ph/0111008

  12. A. Schekochihin, S. Cowley, J. Maron, J., & L. Malyshkin 2002, Phys Rev. E., 65, 6305.

    Google Scholar 

  13. R. Beck., A. Brandenburg, D. Moss, A. Shukurov, D. Sokoloff, Galactic Magnetism: Recent Developments and Perspectives, Ann. Rev. Astron. Astrophys., 34, 155 (1996).

    Article  ADS  Google Scholar 

  14. J. Maron & E.G. Blackman, ApJL 566, L41 (2002).

    Article  ADS  Google Scholar 

  15. E. Vishniac & J. Cho, ApJ, 550 752(2000).

    Article  ADS  Google Scholar 

  16. A. Brandenburg, ApJ, 550 824 (2001)

    Article  ADS  Google Scholar 

  17. H.K. Moffatt, H. K. Magnetic Field Generation in Electrically Conducting Fluids, (Cambridge University Press, Cambridge, 1978).

    Google Scholar 

  18. F. Krause & K.-H. Rädler Mean-field magnetohydrodynamics and dynamo theory, (Pergamon Press, New York, 1980).

    MATH  Google Scholar 

  19. M. Steenbeck, F. Krause, & K.-H. Rädler, Z. Naturforsch. 21a, 369 (1966).

    ADS  Google Scholar 

  20. S.A. Balbus & J. Hawley, Rev. Mod. Phys. 70, 1 (1998).

    Article  ADS  Google Scholar 

  21. T.G. Cowling, Magnetohydrodynamics, (Wiley Interscience, New York, 1957).

    Google Scholar 

  22. J.H. Piddington, Cosmical Electrodynamics, (Krieger Press, Malbar, 1981).

    Google Scholar 

  23. S.I. Vainshtein & F. Cattaneo, ApJ 393 165 (1992).

    Article  ADS  Google Scholar 

  24. L.L. Kitchatinov, V.V. Pipin, G. Rüdiger, G., & M. Kuker, Astron. Nachr., 315, 157 (1994).

    Article  MATH  ADS  Google Scholar 

  25. F. Cattaneo, & D.W. Hughes, Phys. Rev. E. 54, 4532(1996).

    Article  ADS  Google Scholar 

  26. E.G. Blackman & A. Brandenburg, submitted to ApJ (2002); http://xxx.lanl.gov/abs/astro-ph/0204497.

  27. S. Vainshtein, Phys. Rev. Lett., 80, 4879 (1998).

    Article  ADS  Google Scholar 

  28. A. Brandenburg, W. Dobler, & K. Subramanian, Astron. Nachr, 323 99 (2002).

    Article  MATH  ADS  Google Scholar 

  29. A. Brandenburg, A. Bigazzi, & K. Subramanian, MNRAS 325 685 (2001)

    Article  ADS  Google Scholar 

  30. G.B. Field & E.G. Blackman, ApJ 572 685 (2002).

    Article  ADS  Google Scholar 

  31. A. Pouquet, U. Frisch, & J. Léorat, J. Fluid Mech. 77, 321 (1976).

    Article  MATH  ADS  Google Scholar 

  32. G.B. Field in Magnetospheric Phenomena in Astrophysics, R. Epstein & W. Feldman, eds. AIP Conference Proceedings 144 (American Institute of Physics, Mellville NY, 1986), p324.

    Google Scholar 

  33. E.G. Blackman, & G.B. Field, Astrophys. J.534 984 (2000a).

    Article  ADS  Google Scholar 

  34. M.A. Berger & G.B. Field, J. Fluid Mech. 147 133 (1984).

    Article  ADS  MathSciNet  Google Scholar 

  35. J.W. Bieber & D.M. Rust, ApJ, 453 911 (1995)

    Article  ADS  Google Scholar 

  36. D.M. Rust & A. Kumar, Astrophys. J. 464, L199 (1994).

    Article  ADS  Google Scholar 

  37. J.A. Markiel & J.H. Thomas, Astrophys. J. 523 827 (1999)

    Article  ADS  Google Scholar 

  38. A. Ruzmaikin, in Magnetic Helicity in Space and Laboratory Plasmas, edited by A. Pevtsov, R. Canfield, & X. Brown, (Amer. Geophys. Union, Washington, 1999), p111; M.A. Berger & A. Ruzmaikin, Journ. Geophys. Res. 105, 110481

    Google Scholar 

  39. U. Frisch, A. Pouquet, J. Léorat & A. Mazure, J. Fluid Mech. 68, 769 (1975).

    Article  MATH  ADS  Google Scholar 

  40. G.L. Withbroe, & R.W. Noyes, Ann. Rev. Astron. Astrophys. 15, 363 (1977)

    Article  ADS  Google Scholar 

  41. E.G. Blackman, & G.B. Field, Mon. Not. R. Astron. Soc. 318, 724 (2000a).

    Article  ADS  Google Scholar 

  42. B.D. Savage, in The Physics of the Interstellar Medium and Intergalactic Medium, A. Ferrara, C.F. McKee, C. Heiles, & P.R. Shapiro eds. ASP conf ser vol 60. (Astronomical Society of the Pacific, San Francisco, 1995), p233.

    Google Scholar 

  43. R.J. Reynolds, L.M. Haffner, S.L. Tufte, Astrophys. J. 525, L21 (1999).

    Article  ADS  Google Scholar 

  44. M. DeVries & J. Kuijpers, Astron. & Astrophys. 266, 77 (1992); F. Haardt & L. Maraschi, Astrophys. J. 413, 507 (1993); G.B. Field & R.D. Rogers., Astrophys. J. 403, 94 (1993); T. DiMatteo E.G. Blackman & A.C. Fabian, Mon. Not. R. Astron. Soc. 291 L23 (1997); A. Merloni & A.C. Fabian, Mon. Not. R. Astron. Soc. 332 165 (2000).

    ADS  Google Scholar 

  45. H. Ji, Phys. Rev. Lett. 83 3198 (1999); H. Ji in Magnetic Helicity in Space and Laboratory Plasmas, edited by A. Pevtsov, R. Canfield, & X. Brown, (Amer. Geophys. Union, Washington, 1999), p167; H. Ji, & Prager, S. C. in press Magnetohydrodynamics, astro-ph/0110352(2001)

    Article  ADS  Google Scholar 

  46. A.V. Gruzinov & P.H. Diamond P.H., Phys. Rev. Lett., 72 1651 (1994); A.V. Gruzinov & P.H. Diamond, Physics of Plasmas, 2 1941 (1995)

    Article  ADS  Google Scholar 

  47. A.V. Gruzinov & P.H. Diamond, Physics of Plasmas, 3 1853 (1996).

    Article  ADS  Google Scholar 

  48. A. Bhattacharjee & Y. Yuan, Astrophys. J. 449 739 (1995).

    Article  ADS  Google Scholar 

  49. N. Kleeorin, D. Moss, D., I. Rogachevskii, D. Sokoloff, A&A, 361 L5 (2000)

    ADS  Google Scholar 

  50. N. Kleeorin, I. Rogachevskii, A. Ruzmaikin, A&A, 297 L59 (1995)

    ADS  Google Scholar 

  51. N. Kleeorin & I. Rogachevskii, Phys. Rev. E., 59 6724 (1999)

    Article  ADS  MathSciNet  Google Scholar 

  52. G.B. Field, E.G. Blackman, & H. Chou, Astrophys. J. 513, 638 (1999).

    Article  ADS  Google Scholar 

  53. Ya.-B. Zeldovich, Sov Phys. JETP, 4 460 (1957).

    Google Scholar 

  54. E.G. Blackman and G.B. Field, Physics of Plasmas, 8 2407 (2001)

    Article  ADS  Google Scholar 

  55. E.G. Blackman & G.B. Field, Astrophys. J. 521 597 (1999).

    Article  ADS  Google Scholar 

  56. W.N. Brandt, T. Boller, A.C. Fabian, & M. Ruszkowski, Mon. Not. R. Astron. Soc. 303, L53 (1999).

    Article  ADS  Google Scholar 

  57. R.R. Rafikov & R.M. Kulsrud, Mon. Not. R. Astron. Soc. 314, 839 (2000).

    Article  ADS  Google Scholar 

  58. F. Cattaneo, Astrophys. J. 434, 200 (1994).

    Article  ADS  Google Scholar 

  59. A. Brandenburg, & W. Dobler A&A, 369 329 (2001).

    Article  MATH  ADS  Google Scholar 

  60. R. Arlt & A. Brandenburg A&A 380, 359 (2001)

    Article  MATH  ADS  Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Editor information

Editors and Affiliations

Rights and permissions

Reprints and permissions

Copyright information

© 2003 Springer-Verlag Berlin Heidelberg

About this chapter

Cite this chapter

Blackman, E.G. (2003). Recent Developments in Magnetic Dynamo Theory. In: Falgarone, E., Passot, T. (eds) Turbulence and Magnetic Fields in Astrophysics. Lecture Notes in Physics, vol 614. Springer, Berlin, Heidelberg. https://doi.org/10.1007/3-540-36238-X_16

Download citation

  • DOI: https://doi.org/10.1007/3-540-36238-X_16

  • Published:

  • Publisher Name: Springer, Berlin, Heidelberg

  • Print ISBN: 978-3-540-00274-1

  • Online ISBN: 978-3-540-36238-8

  • eBook Packages: Springer Book Archive

Publish with us

Policies and ethics