文章基本信息

标题：Comparative Study of Magnetic Pc-Type Pulsations at Low and High Latitudes (II) : Pc 3 Pulsations (d. ULF Waves in the Magnetosphere) (Proceedings of the Second Symposium on Coordinated Observations of the Ionosphere and Magnetosphere in the Polar Regions
其他标题：低緯度および高緯度におけるPc型地磁気脈動の特性の対比(II) : Pc 3型脈動(d.磁気圏内のULF波動)(第2回極域における電離圏磁気圏総合観測シンポジウム : Part I)
本地全文：下载
作者：Makoto KAWAMURA ; Yuk1zo SANO ; Masayuki KUWASHIMA 等
期刊名称：Antarctic Record
印刷版ISSN：0085-7289
电子版ISSN：2432-079X
出版年度：1980
卷号：68
DOI：10.15094/00008134
语种：English
出版社：National Institute of Polar Research
摘要：Four observatories, Memambetsu, Kakioka, Kanoya and Chichi-jima, constitute Japanese meridian-chain stations for the study of geomagnetic pulsations. Using mainly the data obtained at Memambetsu which is the northernmost one of these observatories, characteristics of the long-term and diurnal variations of mean period and occurrence frequency of Pc 3 observed at low latitudes were investigated statistically. Then, the characteristics were compared with those at higher latitudes (auroral zone and plasmapause). In the analysis, autopower spectrum and dynamic spectrum of Pc 3-range pulsations observed at the Syowa meridian-chain stations, Syowa Station, SANAE and Hermanus, were used mainly. The results are summarized as follows : 1) There is a solar-cycle variation in the mean period of Pc 3. The varia- tion can be related closely to the change in size of the plasmasphere 2) PC 3 period shows such a characteristic annual variation as to become the shortest at the summer solstice. 3) Solar-cycle and seasonal variations of occurrence frequency of Pc 3 represent clearly dependence of the frequency on the geomagnetic activity. 4) PC 3 is a daytime phenomenon which has an occurrence peak just before noon, but the peak shifts to earlier hours of day as the geomasnetic activity heightens. 5) Diurnal variation of the period of Pc 3 shows "Inverted-U type" only in the summer of sunspot maximum years (1957-1961). In the other seasons and in the sunspot minimum years it is not so clear or shows rather "U type", However, on highly disturbed days the period shows a characteristic diurnal variation and the time when it becomes the shortest shifts to the morning side. 6) PC 3 has a good correlation in its activity over a wide latitudinal range, but the spectral components at low latitudes are very different from those at higher latitudes.
其他摘要：われわれの地磁気脈動観測所網のなかで最も北にある女満別の資料を用い,低緯度Pc 3の周期・出現頻度の諸変化の特性を統計的に調べた.次にPc 3の波形・スペクトル特性により,低緯度(Hermanus)から極光帯(昭和基地)にわたるその特性を比較した.えられた結果は次のように要約される.1)周期の太陽周期変化・日変化は,プラスマ圏のサイズ変化・非対称性によって説明される.またJune solsticeに最も短かくなる特徴のある周期の年変化がある.2)出現頻度は,地磁気活動度に依存する太陽周期変化・年変化をする.最大頻度・最短周期の出現時刻は,地磁気活動度の増加につれて正午直前から朝側に移行する.3)低緯度では周期・出現時間に大きな日々変化があるが,高緯度では日による変化は小さい.その出現は広い緯度範囲でよく対応するが,スペクトル成分は緯度依存性をもち,特に低緯度Pc 3は複雑な成分を含む.