Auroral E-region electron density gradients measured with EISCAT
Auroral E-region electron density gradients measured with EISCAT
复制标题
使用 EISCAT 测量的极光 E 区电子密度梯度
DOI：
10.1007/s00585-000-1172-x
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发表时间：
2000
影响因子：
1.9
通讯作者：
G. Hussey
中科院分区：
文献类型：
--
作者：
C. Haldoupis;K. Schlegel;G. Hussey
在E区等离子体不稳定性理论中，环境电场和电子密度梯度都包含在相同的色散关系中，作为提供静电等离子体波产生和增长能量的关键参数。虽然有许多电离层电场的测量，有很少的测量和有限的知识，周围的电子密度梯度，在theE区等离子体中，Ne。本文利用EISCAT CP 1数据库，统计研究了在向东和向西电急流条件下，不同环境电场水平下，极光E区高度的垂直电子密度梯度长度Lz=Ne/（dNe/dz）。总的来说，占主导地位的电子密度梯度，与Lz范围从4至7公里，被发现位于100公里以下，但移动稳定的高度作为电场水平的增加。最陡的密度梯度，Lz可能小于3公里，发生在110公里附近主要是在向东的电急流在强电场的时候。在线性梯度漂移不稳定性理论的框架下对结果及其意义进行了检验和讨论。最后，它将是有趣的测试与垂直雷达干涉仪目前的结果的影响。
In the theory ofE-region plasma instabilities, the ambient electric field and electron density gradient are both included in the same dispersion relation as the key parameters that provide the energy for the generation and growth of electrostatic plasma waves. While there exist numerous measurements of ionospheric electric fields, there are very few measurements and limited knowledge about the ambient electron density gradients, ▽Ne, in theE-region plasma. In this work, we took advantage of the EISCAT CP1 data base and studied statistically the vertical electron density gradient length,Lz=Ne/(dNe/dz), at auroralE-region heights during both eastward and westward electrojet conditions and different ambient electric field levels. Overall, the prevailing electron density gradients, withLzranging from 4 to 7 km, are found to be located below 100 km, but to move steadily up in altitude as the electric field level increases. The steepest density gradients, withLzpossibly less than 3 km, occur near 110 km mostly in the eastward electrojet during times of strong electric fields. The results and their implications are examined and discussed in the frame of the linear gradient drift instability theory. Finally, it would be interesting to test the implications of the present results with a vertical radar interferometer.