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Mean Electromotive Force Due to Magnetoconvection in Rotating Horizontal Layer in Dependence on Boundary Conditions

Published online by Cambridge University Press:  19 July 2016

J. Brestenský ,
S. Ševčík  and
L. Rosenberg
J. Brestenský
Affiliation:
Department of Geophysics, Faculty of Mathematics and Physics, Comenius University, 84215 Bratislava, CSFR
S. Ševčík
Affiliation:
Department of Geophysics, Faculty of Mathematics and Physics, Comenius University, 84215 Bratislava, CSFR
L. Rosenberg
Affiliation:
Department of Geophysics, Faculty of Mathematics and Physics, Comenius University, 84215 Bratislava, CSFR

Abstract

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The instability due to a vertical uniform temperature gradient is studied in a rapidly rotating horizontal layer of an electrically conducting fluid permeated by an azimuthal magnetic field linearly growing with the distance from the vertical axis of rotation. In addition to the boundary conditions used in So ward's study (1979), that is, force-free surface and perfect electrical and thermal conductivity outside, also other conditions more realistic for the Earth's core are considered, that is, rigid surface and electrically insulating walls. Using the concept of meanfield mlid mean electromotive and ponderomotive forces (E.M.F. and P.M.F.) are calculated and compared for various boundary conditions. The dependence of the E.M.F. and P.M.F. on the electromagnetic boundary conditions is strong (slight) if the boundaries are free (rigid).

Keywords

Hydromagnetic instabilitiesmean electromotive forceEarth's core
Type
10. Geodynamo and Planetary Dynamos
Information
Symposium - International Astronomical Union , Volume 157: The Cosmic Dynamo , 1993 , pp. 457 - 461
Copyright
Copyright © Kluwer 1993 

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