VLF Emission Study at Syowa Station,Antarctica -Polar Chorus Emission and Worldwide Geomagnetic Variation-
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概要
- 論文の詳細を見る
Observations of natural electromagnetic noise in the VLF range have been carried out at Syowa Station, Antarctica, since April, 1966. The VLF observation system is briefly described and the result on VLF emissions known as polar chorus is presented, based on the data obtained in 1966. It is confirmed that polar chorus in the auroral zone is a daytime phenomenon and that its occurrence culminates in the summer season. The statistical analysis indicates that a definite positive correlation exists between polar chorus activity and magnetic activity, especially during periods of moderate magnetic condition. Comparison of VLF data with magnetograms from low latitude stations reveals that VLF chorus variations are closely related to ssc, si and other worldwide magnetic changes, and that in several cases the chorus intensity decreases are associated with solar flares. Sudden impulse type magnetic field variations, which are thought to be caused by compression or expansion of the magnetosphere, are associated in most cases with polar chorus variation in the daytime, and a positive impulse is accompanied by a sudden enhancement or commencement of chorus, whereas a negative impulse is associated with a sudden decrease or fadeout of chorus emission. The center frequency of chorus tends to increase at the time of positive magnetic variations, and the rate of this frequency change is closely related to the magnitude of the corresponding magnetic variation. These characteristics are explained by electron cyclotron instability in the daytime magnetosphere, L=6〜10.
- 国立極地研究所の論文
著者
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Oguti Takasi
Geophysics Research Laboratory, University of Tokyo
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Kokubun Susumu
Geophysics Research Laboratory, University of Tokyo
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Oguti Takasi
Department Of Physics Kyushu University
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Oguti Takasi
Geophysical Research Laboratories University Of Tokyo
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Kokubun Susumu
Geophysics Research Laboratory University Of Tokyo
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Kokubun Susumu
Geophysics Research Laboratory The University Of Tokyo
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Hayashi Kanji
Geophysics ResearchLaboratory, University of Tokyo
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Hayashi Kanji
Geophysics Research Laboratory University Of Tokyo
関連論文
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- Inter-Relations among the Upper Atmosphere Disturbance Phenomena in the Auroral Zone
- Modes of pulsating auroras and related geomagnetic pulsations
- Estimation of electric field fluctuations below the auroral ionosphere
- A case study of VLF phase and amplitude variation at 12.1 kHz (Aldra) in Iceland
- Attitude determination of the Antarctic sounding rockets S-310JA-11 and -12
- Measurement of auroral magnetic field with the Antarctic sounding rocket S-310JA-12
- Relationships between pulsating auroras and field-aligned electric currents
- HF doppler measurement in the auroral ionosphere
- VLF Emission Study at Syowa Station,Antarctica -Polar Chorus Emission and Worldwide Geomagnetic Variation-
- Drifts of auroral structures and their relationship to geomagnetic activity
- Photographic Atlas of Auroral Forms Observed at Syowa Station (AERONOMY)
- Spatial Distributions of Auroral Zone X-Rays as Viewed from Rocket Altitudes
- Photographic Atlas of Auroral Forms Observed at Syowa Station
- Metamorphoses of Aurora
- Precipitating Electrons Observed on Board the Japanese Antarctic Sounding Rockets S-310JA-1 and S-310JA-2
- A New Method for Direction Finding of Elliptically Polarized VLF Waves
- Characteristics of transient magnetic field events in the dayside magnetosphere
- Geomagnetically Conjugate Relationship of Polar Geomagnetic Disturbances -Particularly the Distinct Geomagnetic Conjugacy between Syowa Station in Antarctica and Reykjavik in Iceland
- Magnetic Field Survey with the Aid of Polar Patrol Balloons in Antarctica.