Characteristics of Low-Latitude Pi 2 Pulsations along the 210° Magnetic Meridian
Characteristics of Low-Latitude Pi 2 Pulsations along the 210° Magnetic Meridian
复制标题
210°磁子午线低纬度 Pi 2 脉动特征
DOI：
10.5636/jgg.48.1421
复制
发表时间：
1996
期刊：
影响因子：
--
通讯作者：
B. J. Fraser
中科院分区：
文献类型：
--
作者：
H. Osaki;K. Yumoto;K. Fukao;K. Shiokawa;F. Menk;B. J. Fraser
为了了解低纬Pi 2地磁脉动沿着磁子午线的特征，我们分析了阿德莱德地磁场1年的观测资料（地磁纬度Φ = -46.72°），Birdsville（-37.08°）、韦帕（-23.06°）、关岛（9.02°）、千岛（20.65°）、鹿儿岛（25.23°）和茂尻（37.76°）台站沿210°磁子午线沿着。低纬度地区的气候特征（|Φ| < 50°）的Pi 2脉动：（1）80%的H分量和D分量Pi 2事件具有非常相似的波形和相同的频率分量：（2）在± 5s内不仅观测到H分量Pi 2事件，而且观测到D分量Pi 2事件;（3）H分量的Pi 2振幅几乎在同一量级，而D分量的Pi 2脉动在磁赤道附近有一个极小值，从低纬到高纬呈指数增长;（4）在夏季半球，观测到的H分量和D分量Pi 2脉动的振幅都比冬季半球大。结果1和2表明，低纬Pi 2脉动不是传播模，而是内磁层的全球模振荡。结果4不能用电离层中的普通屏蔽效应来解释，但为低纬度Pi 2脉动的未解决的产生机制提供了线索。
In order to understand the characteristics of lower-latitude Pi 2 geomagnetic pulsations along a magnetic meridian, we have analyzed 1 year's data from the Adelaide (geomagnetic latitude Φ = -46.72°), Birdsville (-37.08°), Weipa (-23.06°), Guam (9.02°), Chichijima (20.65°), Kagoshima (25.23°), and Moshiri (37.76°) stations along the 210° magnetic meridian. The characteristics ofthe lower-latitude (|Φ| < 50°) Pi 2 pulsations are summarized as follows: (1) 80% ofH- and D-component Pi 2 events show very similar wave forms and the same frequency component; (2) not only H-component Pi 2 events but also D-component Pi 2 events are observed within ±5 s; (3) H-component Pi 2 amplitudes are of almost the same order, but D-component Pi 2 pulsations have a minimum near the magnetic equator and increase exponentially from lower to higher latitudes; (4) the observed amplitudes of both H- and D-component Pi 2 pulsations are larger in the summer hemisphere than in the winter hemisphere. Results 1 and 2 show that lower-latitude Pi 2 pulsations are not propagating-mode but global-mode oscillations in the inner magnetosphere. Result 4 cannot be explained by the ordinary screening effect in the ionosphere but gives a clue to the unresolved generation mechanism of lower-latitude Pi 2 pulsations.