| Project/Area Number |
13573006
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 海外学術 |
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| Research Field |
Space and upper atmospheric physics
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| Research Institution | Nagoya University |
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Principal Investigator |
SHIOKAWA Kazuo Nagoya University, Solar-Terresrial Environment Laboratory, Associate Professor, 太陽地球環境研究所, 助教授 (80226092)
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| Co-Investigator(Kenkyū-buntansha) |
OGAWA Tadahiko Nagoya University, Solar-Terresrial Environment Laboratory, Professor, 太陽地球環境研究所, 教授 (60271607)
NISHINO Masanori Nagoya University, Solar-Terresrial Environment Laboratory, Associate Professor, 太陽地球環境研究所, 助教授 (70023679)
OTSUKA Yuichi Nagoya University, Solar-Terresrial Environment Laboratory, Assistant Professor, 太陽地球環境研究所, 助手 (40314025)
YUMOTO Kiyohumi Kyushu University, Graduate School of Science, Professor, 大学院・理学研究院, 教授 (20125686)
SAITO Akinori Kyoto University, Graduate School of Science, Assistant Professor, 大学院・理学研究科, 助手 (10311739)
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| Project Period (FY) |
2001 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥12,200,000 (Direct Cost: ¥12,200,000)
Fiscal Year 2004: ¥2,800,000 (Direct Cost: ¥2,800,000)
Fiscal Year 2003: ¥2,600,000 (Direct Cost: ¥2,600,000)
Fiscal Year 2002: ¥2,900,000 (Direct Cost: ¥2,900,000)
Fiscal Year 2001: ¥3,900,000 (Direct Cost: ¥3,900,000)
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| Keywords | thermosphere / ionosphere / traveling ionospheric disturbance / plasma bubble / international network observation (U.S.A., Australia) / 国際情報交換 / アメリカ:オーストラリア / 国際情報交換(アメリカ,オーストラリア) |
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| Research Abstract |
(1)We have investigated a nighttime medium-scale traveling ionospheric disturbance(MSTID) observed by an airglow imager at Shigaraki, Japan. The structure was identified in the airglow images of OI (630.0 nm and 777.4 nm) as NW-SE band structures moving southwestward with a velocity of 50 m/s. We found that an electric field oscillation of -1.2 mV/m was sufficient to reproduce the observed airglow amplitudes. This modeled electric field was comparable to that observed by the DMSP F15 satellite as it passed over Shigaraki during our observing period. The DMSP ion drift data show that the oscillation of the polarization electric field correlated with the MSTID structure in the airglow image.
(2)We found a large-scale equatorial F-region airglow depletions extending to low-midlatitudes in both hemispheres. The observational sites were located at low-midlatitude geomagnetic conjugate points. Clear depletions of 630.0-nm airglow intensity due to equaterial plasma bubbles were simultaneously observed with two all-sky imagers at Sata, Japan (magnetic latitude 24° N), and its geomagnetic conjugate point, Darwin, Australia (magnetic latitude 22° S). These observations indicate that plasma depletions in the equatorial ionosphere elongate along the geomagnetic field lines.
(3)We report for the first time simultaneous observations of MSTIDs at geomagnetic conjugate points in both hemispheres, using two all-sky airglow imagers at midlatitudes. A 630-nm all-sky imager at Sata, Japan, detected MSTIDs with a wave front elongated from NW to SE. MSTIDs with a wave front elongated from SW to NE were observed at the geomagnetic conjugate point, Darwin, Australia. The MSTID structures mapped from Darwin to its magnetic conjugate points along the geomagnetic field lines coincide closely with those in the Sata images. This result suggests that polarization electric field plays an important role in the generation of MSTIDs.
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