Statistical characteristics of small‐scale spatial and temporal electric field variability in the high‐latitude ionosphere
Statistical characteristics of small‐scale spatial and temporal electric field variability in the high‐latitude ionosphere
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高纬度电离层小尺度时空电场变化统计特征
DOI：
10.1029/2011ja017383
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发表时间：
2012
影响因子：
--
通讯作者：
S. Shepherd
中科院分区：
文献类型：
--
作者：
E. Cousins;S. Shepherd
[1]利用两个半球的超级双极光雷达网（SuperDARN）雷达48个月的数据，研究了地球电离层高纬度地区小尺度空间和时间电场变化的统计特征。电场波动的空间尺度在45公里和450公里之间，时间尺度在2分钟和20分钟之间。结果表明，脉动的分布形状和尺度-尺寸依赖性与湍流的预期性质一致。所观察到的空间和时间的变化主要是由背景等离子体漂移的剪切或梯度的大小和季节和太阳周期的影响，这表明等离子体的不稳定性和梯度的电导作为电场的变化的来源。空间和时间的变化之间的关系进行了研究，它被发现的波动很可能是对流静态和时变结构的混合物。还观察到，小规模的变化具有统计特征，在两个半球是非常相似的。出于实际目的，尽管拉伸指数函数与数据最佳匹配，但可以使用指数函数来近似观察到的电场波动的分布，从而能够直接生成近乎真实的随机波动。引文：Escherins，E. D. P.，和S. G. Shepherd（2012），高纬度电离层小尺度空间和时间电场变化的统计特征，J. Geophys.结果：117，A03317，doi：10.1029/2011JA017383。
[1] The statistical characteristics of small-scale spatial and temporal electric field variability in the high-latitude regions of Earth’s ionosphere are investigated using 48 months of data from the Super Dual Auroral Radar Network (SuperDARN) radars in both hemispheres. Electric field fluctuations on spatial scales between 45 km and 450 km and on temporal scales between 2 min and 20 min are considered. It is found that both the distribution shapes and scale-size dependencies of the fluctuations are consistent with the expected properties of a turbulent flow. The observed spatial and temporal variability is influenced primarily by the magnitude of the shear or gradient in the background plasma drift and by season and solar cycle, suggesting plasma instabilities and gradients in the conductance as sources of the electric field variability. The relationship between spatial and temporal variability is investigated and it is found that the fluctuations are likely to be a mixture of convecting static and time-varying structures. It is also observed that the small-scale variability has statistical characteristics that are very similar in the two hemispheres. For practical purposes, although a stretched exponential function best matches the data, the distribution of observed electric field fluctuations can be approximated using an exponential function, enabling straightforward generation of nearly realistic random fluctuations. Citation: Cousins, E. D. P., and S. G. Shepherd (2012), Statistical characteristics of small-scale spatial and temporal electric field variability in the high-latitude ionosphere, J. Geophys. Res., 117, A03317, doi:10.1029/2011JA017383.