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Author(s):
A. Kageyama, T. Sato and The Complexity Simulation Group
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Title:
Computer Has Solved A Historical Puzzle: Generation of Earth's Dipole Field
Date of publication:
June 1995
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Key words:
dynamo, geodynamo, MHD dynamo
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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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