| Project/Area Number |
62420013
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| Research Category |
Grant-in-Aid for General Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
Space and upper atmospheric physics
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| Research Institution | The University of Tokyo |
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Principal Investigator |
KOKUBUN Susumu University of Tokyo, Faculty of Science, Professor, 理学部, 教授 (00011502)
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| Co-Investigator(Kenkyū-buntansha) |
MIURA Akira University of Tokyo, Faculty of Science, Research Associate, 理学部, 助手 (20126171)
HAYASHI Kanji University of Tokyo, Faculty of Science, Associate Professor, 理学部, 助教授 (60011730)
IIJIMA Takesi University of Tokyo, Faculty of Science, Associate Professor, 理学部, 助教授 (70011624)
TAMAO Tsutomu University of Tokyo, Faculty of Science, Professor, 理学部, 教授 (50013636)
OGUTI Takasi Nagoya University, Res.Inst. of Atmospherics, Professor, 空電研究所, 教授 (40011457)
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| Project Period (FY) |
1987 – 1989
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| Keywords | Aurora / Magnetospheric Plasma Waves / Magnetosphere-Ionosphere Coupling / Field-Aligned Current / Magnetospheric Substorms / Geomagnetic Pulsations |
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| Research Abstract |
In order to analyze a plenty of data efficiently, which were obtained in the multi-station campaign in 1985-86 and with spacecraft, a work station, VAX 3200, was installed with a graphic software [UNIRAS]. We developed several software for processing of aurora image data and for frequency-time displays of spectra of various time series, etc.. These software have been used for the analyses of UV auroral images and triaxial search coil data from the EXOS-D satellite launched in February, 1989. We obtained global pictures of expanded oval and high-time resolution images for the initial brightening of auroral substorm in an expanded oval during large magnetic storms. Search coil measurements of ELF electromagnetic noises reveal the existence of a variety of ELF plasma waves near the equatorial plasmasphere of L values, 1.5-2.5 as well as along the auroral field lines.
Analyses of magnetic field data from ISEE and AMPTE/CCE spacecraft have been made to investigate signatures of field-aligned
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currents in the boundary of the plasmasheet and in the near-tail region, and properties of bimodal magnetic impulses like flux transfer events near the dayside magnetopause. The statistical analysis of ISEE data indicates that the field-aligned current signatures in the near-tail region are consistent with observations at low-altitudes. The ballooning instability in the magnetosphere was theoretically examined in relation to the excitation mechanism of compressional Pc 5 waves, which are shown to be confined to a localized region near the magnetic equator.
Dynamic morphology of auroras has been studied by using high-resolution TV data obtained simultaneously at several ground stations. It is found that development of north-south aligned-arcs is an essential feature in the central region of auroral substorm and that correspond to appearances of dispersionless electron injections at geosynchronous orbit. Dispersive electron injections at synchronous orbit are observed in local time sector conjugate to the region of pulsation auroras. Less
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