A statistical study of dayside magnetospheric electric field fluctuations with periods between 150 and 600 s
A statistical study of dayside magnetospheric electric field fluctuations with periods between 150 and 600 s
复制标题
周期为150~600 s的日侧磁层电场涨落统计研究
DOI：
10.1029/ja089ia07p05495
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发表时间：
1984
影响因子：
--
通讯作者：
B. Higel
中科院分区：
文献类型：
--
作者：
H. Junginger;G. Geiger;G. Haerendel;F. Melzner;E. Amata;B. Higel
GEOS 2电子束实验186天的电场数据已用于研究地球静止轨道磁层涨落，周期在150至600秒之间。虽然来自日侧磁层的电场数据中几乎总是存在波动，其典型幅度在 0.2 至 0.5 mV/m 之间，但通常很难在 GEOS 2 磁场数据中找到明确的并发脉动。大多数事件发生在中午附近，并具有相同的特征：它们是环形的，几乎是线性极化的，极化方向和极化椭圆的方向角在中午附近改变符号，波动的瞬时频率与瞬时电子密度相关，并且在磁层的给定扇区中，极化方向取决于频率。有强有力的证据表明，这些涨落是航天器附近磁力线的基本模式本征振荡，是由磁层顶或低纬边界层的某种太阳风驱动的表面波在磁层的不均匀等离子体中产生的。
One hundred eighty-six days of electric field data from the GEOS 2 electron beam experiment have been used to study magnetospheric fluctuations at geostationary orbit with periods between 150 and 600 s. While fluctuations are nearly always present in the electric field data from the dayside magnetosphere with typical amplitudes between 0.2 and 0.5 mV/m, it is often hard to find well-defined concurrent pulsations in the GEOS 2 magnetic field data. Most events occur near noon and have the same characteristics: They are toroidal and nearly linearly polarized, the sense of polarization and the orientation angles of the polarization ellipses change sign near noon, the instantaneous frequency of the fluctuations is correlated with the instantaneous electron density, and in a given sector of the magnetosphere the sense of polarization depends on the frequency. There is strong evidence that these fluctuations are fundamental mode eigenoscillations of field lines in the vicinity of the spacecraft which are generated in the inhomogeneous plasma of the magnetosphere by some kind of solar wind-driven surface waves at the magnetopause or at the low-latitude boundary layer.