Oscillations in drifts of auroral patches.
Oscillations in drifts of auroral patches.
复制标题
极光斑漂移的振荡。
DOI：
10.5636/jgg.39.609
复制
发表时间：
1987
期刊：
影响因子：
--
通讯作者：
Tatsundo Yamamoto
中科院分区：
文献类型：
--
作者：
T. Oguti;R. Nakamura;Tatsundo Yamamoto
根据全天极光电视记录，微弱的极光斑块（光度无脉动）被发现与地面上同时发生的磁脉动相关的振荡漂移。发现极光斑块漂移中的这些振荡与与并发磁脉动相关的静电电场中的振荡一致。这意味着这些磁脉动是由电离层电流引起的，电离层电流是由与磁层中阿尔文剪切波相关的静电电场产生的。因此，结果表明，同步测量地面磁脉动时极光结构的漂移是检验磁脉动是否真正归因于从磁层向下传播的HM波场，或者本质上是由电离层电导率不均匀性变化引起的一种便捷方法。 It is also shown that the azimuthal phase speed (wave length), as well as the oscillation amplitude, highly varies from the dayside to the evening, i.即，它在白天较大，而在晚上则变得较小。 Theory must take this steep longitudinal non-uniformity into consideration.
On the basis of all-sky TV records of auroras, faint auroral patches (nonpulsating in luminosity) are found to oscillatorily drift associated with concurrent magnetic pulsations on the ground. These oscillations in the drifts of auroral patches are found to be consistent with the oscillations in the electrostatic electric field associated with the concurrent magnetic pulsations. This implies that these magnetic pulsations are brought forth by ionospheric electric currents which are produced by electrostatic electric fields associated with shear Alfven waves in the magnetosphere. The result, therefore, indicates that the simultaneous measurement of the drifts of auroral structures at the time of ground magnetic pulsations is a convenient method of examining whether the magnetic pulsations are really ascribed to HM wave fields propagating down from the magnetosphere, or if they are essentially caused by the change in conductivity inhomogeneity in the ionosphere. It is also shown that the azimuthal phase speed (wave length), as well as the oscillation amplitude, highly varies from the dayside to the evening, i. e., it is larger in the dayside and becomes much smaller toward the evening sectors. Theory must take this steep longitudinal non-uniformity into consideration.