Skip to main content
  • Article
  • Published:

The anisotropy of local turbulence in the Earth’s core

Abstract

The anisotropy of local turbulence in the Earth’s core is examined. It is recognized that small-scale motions in the core are strongly influenced by the Earth’s rotation and its magnetic field. A small region of the core is simulated (the computational box), across which the prevailing large-scale (toroidal) magnetic field is supposed to be uniform and in which the temperature or compositional gradient providing the buoyancy that powers the turbulence is parallel to the (uniform) gravitational field. The simulations are used to estimate the turbulent fluxes of mean fields and their dependence on the latitude at which the computational box is situated. It is found that the effect of local turbulence on the diffusion of large-scale fields is significant, and that turbulent transport is anisotropic. It is believed that the results of the present study will prove useful in determining geophysically realistic diffusivities for use in future global geodynamo simulations.

References

  • Arakawa, C., Computational Fluid Dynamics for Engineering, 229 pp., Tokyo Univ. Press, Tokyo, 1994 (in Japanese).

    Google Scholar 

  • Braginsky, S. I., Magnetohydrodynamics of the Earth’s core, Geomagn. Aeron. (Engl. Trans.), 4, 698–712, 1964.

    Google Scholar 

  • Braginsky, S. I. and V. P. Meytlis, Local turbulence in the Earth’s core, Geophys. Astrophys. Fluid Dynam., 55, 71–87, 1990.

    Article  Google Scholar 

  • Braginsky, S.I. and P.H. Roberts, Equations governing convection in Earth’s core and the geodynamo, Geophys. Astrophys. Fluid Dynam., 79, 1–97, 1995.

    Article  Google Scholar 

  • Glatzmaier, G. A. and P. H. Roberts, A three-dimensional self-consistent computer simulation of a geomagnetic field reversal, Nature, 377, 203–209, 1995a.

    Article  Google Scholar 

  • Glatzmaier, G. A. and P. H. Roberts, A three-dimensional convective dynamo solution with rotating and finitely conducting inner core and mantle, Phys. Earth Planet. Inter., 91, 63–75, 1995b.

    Article  Google Scholar 

  • Kuang, W. and J. Bloxham, An Earth-like numerical dynamo model, Nature, 389, 371–374, 1997.

    Article  Google Scholar 

  • St. Pierre, M. G., On the local nature of turbulence in Earth’s outer core, Geophys. Astrophys. Fluid Dynam., 83, 293–306, 1996.

    Article  Google Scholar 

  • Zhang, K., Nonlinear magnetohydrodynamic convective flows in the Earth’s fluid core, Phys. Earth Planet. Inter., 111, 93–104, 1999.

    Article  Google Scholar 

  • Zhang, K. and C. A. Jones, The effect of hyperviscosity on geodynamo models, Geophys. Res. Lett., 24, 2869–2872, 1997.

    Article  Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Masaki Matsushima.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Matsushima, M., Nakajima, T. & Roberts, P.H. The anisotropy of local turbulence in the Earth’s core. Earth Planet Sp 51, 277–286 (1999). https://doi.org/10.1186/BF03352231

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1186/BF03352231

Keywords