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AGU: Geophysical Research Letters

 

Keywords

  • Martian crustal field
  • dynamo
  • numerical simulation

Index Terms

  • Planetary Sciences: Solid Surface Planets: Magnetic fields and magnetism
  • Planetary Sciences: Solid Surface Planets: Ionospheres
  • Geomagnetism and Paleomagnetism: Dynamo: theories and simulations
  • Geomagnetism and Paleomagnetism: Core processes
  • Geomagnetism and Paleomagnetism: Planetary magnetism: all frequencies and wavelengths

Abstract

Sudden termination of Martian dynamo?: Implications from subcritical dynamo simulations

W. Kuang

Planetary Geodynamics Laboratory, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA

W. Jiang

Joint Center for Earth Systems Technology, University of Maryland, Baltimore County, Baltimore, Maryland, USA

T. Wang

School of Earth Science, Graduate University, Chinese Academy of Science, Beijing, China

The crustal magnetism measured by the Mars Global Surveyor requires that Mars possessed a strong internal field generated by a core dynamo in its early history. We use a numerical model to simulate the early Martian dynamo, focusing on the minimum energy for sustaining an established dynamo. Our results show that near its end, the Martian dynamo could reverse frequently, and could be subcritical: the energy to sustain the dynamo is significantly less than that to excite the dynamo. In addition to a longer lifetime, the subcritical dynamo implies that it could be terminated suddenly with a very small perturbation and, once turned off, it could not be reactivated without substantial increase of the buoyancy force in the Martian core.

Received 1 April 2008; accepted 23 June 2008; published 29 July 2008.

Citation: Kuang, W., W. Jiang, and T. Wang (2008), Sudden termination of Martian dynamo?: Implications from subcritical dynamo simulations, Geophys. Res. Lett., 35, L14204, doi:10.1029/2008GL034183.

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