STORM-TIME MAGNETOSPHERIC CURRENTS INFERRED FROM MIDLATITUDE GEOMAGNETIC-FIELD VARIATIONS
STORM-TIME MAGNETOSPHERIC CURRENTS INFERRED FROM MIDLATITUDE GEOMAGNETIC-FIELD VARIATIONS
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DOI：
10.5636/jgg.42.1249
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发表时间：
1990-01-01
期刊：
影响因子：
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通讯作者：
IYEMORI, T
中科院分区：
文献类型：
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作者：
IYEMORI, T
利用10个中纬度站点的地磁场数据的D和H分量，推导出磁场的纵向对称和非对称分量，对风暴时磁层电流系统进行了研究。D分量的不对称性表明，当IMF向南时，分别在早晨扇区和从晚上到清晨扇区存在向下和向上的净场向流。它还表明，在风暴时间环流发展阶段，下午部分出现了净下行电流。这些建议被Magsat在电离层上的观测证实，因为电离层上的扰动方向与地面上的扰动方向不是相反的，而是相同的。在向南的国际货币基金组织期间，这种向下的水流特征与早晨的水流特征共存，表明在环流的发展阶段，两种不同的水流系统共存。一种是所谓的局部环电流系统，另一种是由IMF-B(z)控制的电流系统。在当地时间，在暗面H分量中可以看到系统的不对称相移，而在D分量中则没有，这表明向西漂移的环流粒子的贡献是H分量不对称的一个不可忽视的原因。
Both D and H components of geomagnetic field data from 10 mid-latitude stations are used to examine the storm-time magnetospheric current system by deriving the longitudinally symmetric and asymmetric components of the fields. The asymmetry in D component suggests that net downward and upward field-aligned currents exist in the morning sector and from the evening to the early morning sector, respectively, when the IMF is southward. It also suggests the appearance of a net downward current in the afternoon sector at the developing stage of the storm-time ring current. These suggestions are confirmed by Magsat observation over the ionosphere since the direction of disturbances over the ionosphere is not the opposite but the same as that on the ground. This downward current signature co-exists with that of the morning sector during the southward IMF, suggesting that two different current systems co-exist at the developing phase of the ring current. One is the so-called partial ring current system whereas the other is the current system controlled by the IMF-B(z). A systematic phase shift of asymmetry in local time is seen in the dusk-side H but not in the D component, indicating that the contribution from westward drifting ring current particles can not be neglected as a cause for the H component asymmetry.