DP 2 electric field fluctuations in the dusk‐time dip equatorial ionosphere
DP 2 electric field fluctuations in the dusk‐time dip equatorial ionosphere
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DOI：
10.1029/98gl01096
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发表时间：
1998-05
影响因子：
5.2
通讯作者：
M. Abdu;J. Sastri;H. Luhr;H. Tachihara;T. Kitamura;N. Trivedi;J. Sobral
中科院分区：
文献类型：
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作者：
M. Abdu;J. Sastri;H. Luhr;H. Tachihara;T. Kitamura;N. Trivedi;J. Sobral
我们利用斯堪的纳维亚半岛和巴西阿尔坎塔拉(倾角1.2°N)图像网络的高时间分辨率磁力仪资料和印度Kodaikanal(倾角4°N)高频多普勒雷达测量的F层垂直等离子体漂移Vz，研究了1995年4月7日发生的DP2活动的地磁和电离层表现。Kodaikanal上空(1730-1900LT)F层垂直等离子体漂移(向东电场)的准周期涨落与日侧倾角赤道和极光/亚极光纬度的DP2型磁涨落(周期≈25min)相一致。这是首次在黄昏赤道观测到的结果，与之前提出的DP2波动的两单元等效电流系统是一致的。结果强烈表明，引起DP2波动的磁层电场在黄昏时和白天时一样穿透到赤道电离层。另外，电场起伏幅度向黑夜方向增大，表明DP2电场的观测特征受黄昏扇形电动力学的影响。
We have studied the geomagnetic and ionospheric manifestations of the DP 2 activity that occurred on April 7, 1995 using high time resolution magnetometer data of IMAGE network in Scandinavia and of Alcantara (dip 1.2° N), Brazil, and F layer vertical plasma drift, Vz measured by an HF Doppler radar at Kodaikanal (dip 4° N), India. Quasi‐periodic fluctuations in dusk‐time (1730–1900 LT) F layer vertical plasma drift (eastward electric field) occurred over Kodaikanal coherent with DP 2 type magnetic fluctuations (period≈25 min) at the day‐side dip equator and auroral/subauroral latitudes. This first‐ever observation at the dusk‐side equator is in agreement with the two‐cell equivalent current system previously proposed for DP 2 fluctuations. The results strongly suggest that the magnetospheric electric field responsible for DP 2 fluctuations penetrates to equatorial ionosphere on the dusk‐side as on the day‐side. An additional observation is that the electric field fluctuation amplitude increases towards the nightside suggesting the influence of dusk sector electrodynamics in the observed signature of the DP 2 electric field.