1996 Fiscal Year Final Research Report Summary
Study of Mechanism of MHD dynamo-Toward Understanding of Geodynamo-
| Project/Area Number |
07640532
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
物理学一般
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| Research Institution | National Institute for Fusion Science |
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Principal Investigator |
KIDA Shigeo National Institute for Fusion Science, Theory and Computer Simulation Center, Professor, 理論・シミュレーション研究センター, 教授 (70093234)
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| Co-Investigator(Kenkyū-buntansha) |
MIURA Hideaki National Institute for Fusion Science, Theory and Computer Simulation Center, As, 理論・シミュレーション研究センター, 助手 (40280599)
TANAKA Mitsuru Kyoto Institute of Technology Department of Mechanical and System Engineering, A, 工芸学部, 助手 (20281115)
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| Project Period (FY) |
1995 – 1996
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| Keywords | Dynamo / Thermal convection |
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| Research Abstract |
The mechanism of generation and sustenance of magnetic field driven thermally in a rotating spherical shell was investigated numerically as one of the simplest models of geody-namo. During the period of the project we obtained the following interesting results. [1] It is the first time in the world that the generation of a strong magnetic field and a quasi-periodic oscillation of magnetic dipole are realized on a computer by solving the MHD equations with-out any simplification. [2] The full three-dimensional structure of the thermal convection which creates the magnetic field was clarified by a detailed analysis of closed streamlines and stagnation points. The relation between the spatial structures of the velocity and the magnetic field is currently being investigated in terms of these streamlines as well as by the eigen-value analysis of the velocity-gradient tensor. [3] It was found that there is a complicated but regular time-variation in both the magnetic and the velocity fields which cause the above-mentioned quasi-periodic reversal of the magnetic dipole moment. [4] A kinematic MHD simulation was performed to reveal that there is a strong spatial correlation between the velocity and the magnetic fields.
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