Abstract A new scaling law for the planetary magnetic field strengths is obtained assuming the magnetostrophic balance. The velocity of the convection current υ c in a planetary core is estimated by the geometric mean of the possible maximum and minimum values to be υ c = c(Ω/4πμσ) 1 2 , where Ω is angular velocity of the core rotation, σ the electric conductivity, c speed of light, and μ the magnetic permeability. Overall agreement of the prediction by the present new scaling law with the data on magnetic field strengths of various planets is superior to those by previously proposed scaling laws. The present scaling law is also found to predict well the Neptune's magnetic field recently determined by the Voyager 2 observation. Success of the present scaling law on the planetary magnetic field strength suggests that the magnetostrophic balance may be a good approximation for planetary dynamo and that toroidal magnetic field is dominant over the poloidal field in the core.


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    Title :

    A new scaling law of the planetary magnetic fields


    Contributors:

    Published in:

    Advances in Space Research ; 12 , 8 ; 265-279


    Publication date :

    1992-01-01


    Size :

    15 pages




    Type of media :

    Article (Journal)


    Type of material :

    Electronic Resource


    Language :

    English



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