Electron Energization by Alfvén Waves: Freja and Sounding Rocket Observations
Electron Energization by Alfvén Waves: Freja and Sounding Rocket Observations
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阿尔芬波的电子能量：Freja 和探空火箭观测
DOI：
10.1238/physica.topical.084a00151
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发表时间：
2000
期刊：
影响因子：
2.9
通讯作者：
M. Berthomier
中科院分区：
文献类型：
--
作者：
Y. Khotyaintsev;N. Ivchenko;K. Stasiewicz;M. Berthomier
最近的探空火箭观测突出了Freja航天器以前观测到的极光电离层现象中的一些时空模糊性。在极光带中，伴随着强非线性电磁扰动，通常可以观察到能量从几十eV到几keV的场向电子布居通过冷背景等离子体。同时观测到的突发朗缪尔辐射表明这些等离子体分布的不稳定性。详细的分析表明，电磁扰动的形式是与惯性阿尔文波有关的准定常非线性空间结构。我们认为，由于电离层密度梯度的不均匀高度分布的平行电场的这些结构负责观察到的电子分布。
Recent sounding rockets observations highlight some space-time ambiguities in phenomena taking place in the auroral ionosphere, previously observed by the Freja spacecraft. Field aligned electron populations with energies from a few tens of eV to a few keV streaming through cold background plasma are usually observed in the auroral zone in association with strongly nonlinear electromagnetic perturbations. Simultaneous observations of bursty Langmuir emissions indicate the unstable character of these plasma distributions. A detailed analysis shows that the electromagnetic perturbations take the form of quasi-stationary nonlinear spatial structures related to inertial Alfvén waves. We suggest that inhomogeneous altitude distribution of the parallel electric field of these structures due to ionospheric density gradientis responsible for the observed electron distributions.