2006 Fiscal Year Final Research Report Summary
Study of substorm simulation
| Project/Area Number |
15540429
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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 |
Space and upper atmospheric physics
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| Research Institution | KYUSHU UNIVERSITY |
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Principal Investigator |
TANAKA Takashi Kyushu University, Earth and Planetary Science, Professor, 理学研究院, 教授 (70346766)
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| Project Period (FY) |
2003 – 2006
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| Keywords | substorm / magnetohydrodymanics / convection / field-aligned current / state transition |
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| Research Abstract |
Convection is the most fundamental process in understanding the structure of geospace and disturbances observed in the magnetosphere-ionosphere (M-I) system. In this study, a self-consistent configuration of the global convection system is considered under the real topology as a compound system. Investigations are made based on the M-I coupling scheme by analyzing numerical results obtained from magnetohydrodynamic (MHD) simulations which guarantee the self-consistency in the whole system under the BV (magnetic field and velocity) paradigm. It is emphasized in the M-I coupling scheme that convection and field-aligned current (FAC) are different aspects of same physical process characterizing the open magnetosphere. Special attention is given in this study to the energy supplying (dynamo) process that drives the FAC system. In the convection system, the dynamo must be constructed from shear motion together with plasma population regimes to steadily drive the convection. Convection patterns observed in the ionosphere are also the manifestation of achievement in global self-consistency. A primary approach to apply these concepts to the study of geospace is to consider how the M-I system adjusts the relative motion between the compressible magnetosphere and the incompressible ionosphere when responding to given solar-wind conditions. The above principle is also applicable for the study of disturbance phenomena such as the substorm as well as for the study of apparently unique processes such as the flux transfer event (FTE), the sudden commencement (SC), and the theta aurora. Finally, an attempt is made to understand the substorm as the extension of enhanced convection under the southward interplanetary magnetic field (IMF) condition.
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[Journal Article] A numerical simulation of geomagnetic sudden commencement : 1. Generation of the Field-aligned current associated with preliminary impulse2003
Author(s)
Fujita, S., T.Tanaka, T.Kikuchi, K.Fujimoto, K.Hosokawa, M.Itonaga
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Journal Title
J, Geophys. Res., 108(A12), 1416, doi : 10.1029/2003JA009763, 2003. 108(A12)
Description
「研究成果報告書概要(和文)」より
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