Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • News & Views
  • Published:

Geophysics

Probing Earth's dynamo

Nature volume 389, pages 337–338 (1997)Cite this article

Most of the planets in our Solar System, Earth among them, have magnetic fields that originate from self-sustaining dynamos; so, too, do the jovian satellites Io and Ganymede, according to the results from the Galileo mission1. Planetary magnetism is a common phenomenon because only three basic ingredients are needed for a dynamo: a sufficiently large volume of electrically conducting fluid somewhere in the planet's interior, an energy source such as convection to circulate the fluid, and planetary rotation to organize the resulting fluid motions. That sounds simple enough. But the inner workings of planetary dynamos have remained stubbornly opaque, mainly because the requirement of a large volume of conducting fluid has prevented the construction of laboratory-scale dynamos and, until recently, has permitted only rudimentary numerical simulations.

On page 371 of this issue2, Kuang and Bloxham report on numerical models of convection-driven dynamos that successfully reproduce many of the observed characteristics of the Earth's magnetic field. Perhaps the most fundamental result is that their model generates an external field dominated by an axial dipole component, like that of the Earth, with an intensity close to the present-day geomagnetic dipole moment. The Kuang-Bloxham dynamo also exhibits westward drift of the non-dipole magnetic field, much like the historically documented westward drift of the geomagnetic field.

This is a preview of subscription content, access via your institution

Access options

Buy this article

  • Purchase on Springer Link
  • Instant access to full article PDF
Buy now

Prices may be subject to local taxes which are calculated during checkout

Figure 1: Alternative models of the primary azimuthal flow in the Earth's liquid outer core, which stem from setting different boundary conditions for the interaction between the inner and outer cores.

References

  1. Kivelson, M. G. et al. Nature 384, 537–541 (1996).

    Google Scholar 

  2. Kuang, W. & Bloxham, J. Nature 389, 371–374 (1997).

    Article  ADS  CAS  Google Scholar 

  3. Glatzmaier, G. A. & Roberts, P. H. Science 274, 1887–1890 (1996).

    Google Scholar 

  4. Bloxham, J. & Jackson, A. J. Geophys. Res. 97, 19537–19563 (1992).

    Google Scholar 

  5. Song, X. D. & Richards, P. G. Nature 382, 221–224 (1996).

    Article  ADS  CAS  Google Scholar 

  6. Su, W.-J., Dziewonski, A. M. & Jeanloz, R. Science 274, 1883–1885 (1996).

    Google Scholar 

Download references

Author information

Authors and Affiliations

  1. the Department of Earth and Planetary Sciences, Johns Hopkins University, Baltimore, 21218, Maryland, USA

    Peter Olson

Authors
  1. Peter Olson
    View author publications

    You can also search for this author in PubMed Google Scholar

Rights and permissions

Reprints and permissions

About this article

Cite this article

Olson, P. Probing Earth's dynamo. Nature 389, 337–338 (1997). https://doi.org/10.1038/38622

Download citation

  • Issue Date:

  • DOI: https://doi.org/10.1038/38622

This article is cited by

Search

Advanced search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing