| Project/Area Number |
08640556
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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 | TOKYO INSTITUTE OF TECHNOLOGY |
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Principal Investigator |
NAGAI Tsugunobu Guraduate School of Science and Engineering, Tokyo Institite of Technology, Professor, 大学院・理工学研究科, 教授 (60260527)
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| Co-Investigator(Kenkyū-buntansha) |
FUJIMOTO Masaki Guraduate School of Science and Engineering, Tokyo Institite of Technology, Assi, 大学院・理工学研究科, 助教授 (30242811)
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| Project Period (FY) |
1996 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1998: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1997: ¥200,000 (Direct Cost: ¥200,000)
Fiscal Year 1996: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Keywords | radiation belts / magnetosphere / magnetic field / magnetic storm / electron flux / 加速機構 / 静止衛星 / 地磁気活動 / 粒子フラックス / 相対論的電子 / 磁気嵐 / 磁場変動 |
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| Research Abstract |
1.Long-term variation of the electron intensity in the radiation belts
The data base was constructed with the measurements of electrons with energies of 0.30-0.95 MeV, 0.95-2.5 MeV, and > 2.5 MeV with Radiation Monitor on the spacecraft Akebono for the period 1989-1998. The data period covers almost one solar cycle. The electron intensity in the inner part of the outer zone (near L=3) changes in accord with the solar cycle. The electron intensity is high in 1989-1994, whereas it is low during the period of the solar minimum because of infrequent injection to the slot region. The electron intensity in the outer part of the outer zone shows its peak in 1994, whereas it is low during the period of the solar minimum. These results and others are found first on the basis of the long-term continuous measurements with Akebono. This data base provides an important impact on the study of the acceleration mechanisms in the radiation belts particles.
2. Modeling of the electron flux changes in the radiation belts
The model with the time-varying magnetic field and electric field is constructed for studying the electron flux changes in the inner magnetosphere. The simulated changes in the electron intensity have representative characteristics in the radiation belt particles, The model shows that particle injection to the slot region is part of the acceleration process in the outer zone.
3. Prediction of the geosynchronous electron environment
The prediction scheme of the relativistic electron intensity at synchronous orbit is constructed with the input as the index based on in situ magnetic field measurements. The scheme uses a linear prediction filter and it can successfully predict the electron flux one day ahead.
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