NIFS-359

FULL TEXT (PDF, 793 KB)


Author(s):

A. Kageyama, T. Sato and The Complexity Simulation Group

Title:

Computer Has Solved A Historical Puzzle: Generation of Earth's Dipole Field

Date of publication:

June 1995

Key words:

dynamo, geodynamo, MHD dynamo

Abstract:

Computer simulation of a magnetohydrodynamic dynamo is performed. It is found that strong dipole field is self-consistently and preferentially excited by thermal convection of an electrically conducting fluid in a rapidly rotating spherical shell. Thus, the long standing puzzle of the origin of the earth's dipole field is finally resolved. It is also found that radial components of the generated magnetic field are accumulated, with equal intensity and polarity, in all cyclonic convection columns near the outer spherical boundary. This is the reason that the dipole moment becomes dominant over other moments. Therefore, we can conclude that the preferential excitation of the dipole field is a natural consequence of well-organized convection columns.

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