Encyclopedia of Geomagnetism and Paleomagnetism

2007 Edition
| Editors: David Gubbins, Emilio Herrero-Bervera

Dynamo Waves

  • Graeme R. Sarson
Reference work entry
DOI: https://doi.org/10.1007/978-1-4020-4423-6_68

Dynamo waves are oscillating solutions of the induction equation of  magnetohydrodynamics (q.v.), which typically involve magnetic field fluctuations on global scales (possibly including global reversals), and fluctuate with periods related to the timescale of magnetic diffusion (i.e., ca. 103–104 years, for the Earth). They arise as oscillatory solutions of the kinematic  dynamo problem (q.v.): the linear problem for the generation of magnetic field subject to the inductive action of a specified flow. The concept of dynamo waves can be extended beyond the linear regime, however, as the oscillatory behavior is often retained in nonlinear solutions; and in scenarios involving fluctuating velocities, such waves are invoked by several proposed mechanisms for geomagnetic reversals (see  Reversals, theory).

In this usage, dynamo waves should be distinguished from other forms of  magnetohydrodynamic waves (q.v.), including  Alfvén waves (q.v.), and magnetic  torsional oscillations (q.v.)....

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

Bibliography

  1. Aubert, J., and Wicht, J., 2004. Axial vs. equatorial dipolar dynamo models with implications for planetary magnetic fields. Earth and Planetary Science Letters, 221: 409–419.CrossRefGoogle Scholar
  2. Braginsky, S.I., 1964. Kinematic models of the Earth's hydrodynamic dynamo. Geomagnetism and Aeronomy, 4: 572–583 (English translation).Google Scholar
  3. Giesecke, A., Rüdiger, G., and Elstner, D., 2005. Oscillating α 2‐dynamos and the reversal phenomenon of the global geodynamo. Astronomische Nachrichten, 326: 693–700.CrossRefGoogle Scholar
  4. Glatzmaier, G.A., and Roberts, P.H., 1995. A three‐dimensional self‐consistent computer simulation of a geomagnetic field reversal. Nature, 377: 203–209.CrossRefGoogle Scholar
  5. Gubbins, D., 1987. Mechanisms for geomagnetic polarity reversals. Nature, 326: 167–169.CrossRefGoogle Scholar
  6. Gubbins, D., and Gibbons, S., 2002. Three‐dimensional dynamo waves in a sphere Geophysical and Astrophysical Fluid Dynamics, 96: 481–498.CrossRefGoogle Scholar
  7. Gubbins, D., and Sarson, G., 1994. Geomagnetic field morphologies from a kinematic dynamo model. Nature, 368: 51–55.CrossRefGoogle Scholar
  8. Hagee, V.L., and Olson, P., 1991. Dynamo models with permanent dipole fields and secular variation. Journal of Geophysical Research, 96: 11673–11687.Google Scholar
  9. Holme, R., 1997. Three‐dimensional kinematic dynamos with equatorial symmetry: Application to the magnetic fields of Uranus and Neptune. Physics of the Earth and Planetary Interiors, 102: 105–122.CrossRefGoogle Scholar
  10. Moffatt, H.K., 1978. Magnetic Field Generation in Electrically Conducting Fluids. Cambridge: Cambridge University Press.Google Scholar
  11. Parker, E.N., 1955. Hydromagnetic dynamo models. Astrophysical Journal, 121: 293–314.CrossRefGoogle Scholar
  12. Parker, E.N., 1979. Cosmical Magnetic Fields. Oxford: Clarendon Press.Google Scholar
  13. Rädler, K.‐H., Wiedemann, E., Brandenburg, A., Meinel, R., and Tuominen, I., 1990. Nonlinear mean‐field dynamo models: Stability and evolution of three‐dimensional magnetic field configurations. Astronomy and Astrophysics, 239: 413–423.Google Scholar
  14. Roberts, P.H., 1972. Kinematic dynamo models. Philosophical Transactions of the Royal Society of London, Series A, 272: 663–698.CrossRefGoogle Scholar
  15. Takahashi, F., Matsushima, M., and Honkura, Y., 2005. Simulations of a quasi‐Taylor state geomagnetic field including polarity reversals on the Earth simulator. Science, 309: 459–461.CrossRefGoogle Scholar
  16. Wicht, J., and Olson, P., 2004. A detailed study of the polarity reversal mechanism in a numerical dynamo model. Geochemistry Geophysics Geosystems, 5: Q03H10.Google Scholar
  17. Willis, A.P., and Gubbins, D., 2004. Kinematic dynamo action in a sphere: effects of periodic time‐dependent flows on solutions with axial dipole symmetry. Geophysical and Astrophysical Fluid Dynamics, 98: 537–554.CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2007

Authors and Affiliations

  • Graeme R. Sarson

There are no affiliations available