Obliquely propagating ion acoustic waves in the auroral E region: Further evidence of irregularity production by field‐aligned electron streaming
Obliquely propagating ion acoustic waves in the auroral E region: Further evidence of irregularity production by field‐aligned electron streaming
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极光 E 区倾斜传播的离子声波：场对准电子流产生不规则性的进一步证据
DOI：
10.1029/ja095ia06p07833
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发表时间：
1990
影响因子：
--
通讯作者：
J. Ruohoniemi
中科院分区：
文献类型：
--
作者：
J. Villain;C. Hanuise;R. Greenwald;K. Baker;J. Ruohoniemi
位于拉布拉多鹅湾的JHU/APL高频雷达和位于魁北克施特维尔的SHERPA高频雷达获得了E区高纬不规则体在十亿波长上的共同体积观测。在本文中，我们分析了一个事件的特征类似的一个独特的类型的事件描述的Villain等。[1987]。实验配置，结合了鹅湾雷达的方位角扫描能力的频率扫描操作的Schloville雷达，提供了明确的证据，在E区域内的不同高度存在两个不规则层。表现出不同特性的层可以与梯度漂移和离子声学不稳定机制的作用有关。它示出的离子声学模式具有在400至550米/秒的范围内的相速度，并产生在亚临界垂直电子霍尔漂移的区域。我们推断，所观察到的不规则性是通过垂直和场对齐的相对电子-离子漂移的组合产生的。以前观察到的功能，但不能令人满意地解释垂直漂移激励单独可以理解的领域对齐漂移激励。我们的结论是，电子离子场对齐漂移的作用可能比以前实现的更重要。
Common volume observations of E region high-latitude irregularities at decameter wavelengths have been obtained with the JHU/APL HF radar located at Goose Bay, Labrador, and the SHERPA HF radar located at Schefferville, Quebec. In this paper, we analyze an event with characteristics similar to those of a distinctive type of event described by Villain et al. [1987]. The experimental configuration, which combines the azimuthal-scanning capability of the Goose Bay radar with the frequency-scanning operation of the Schefferville radar, has provided unambiguous evidence of the existence of two irregularity layers at different altitudes within the E region. The layers, which exhibit different characteristics, can be related to the action of the gradient drift and ion acoustic instability mechanisms. It is shown that the ion acoustic modes have phase velocities in the range of 400 to 550 m/s and are produced in regions of subcritical perpendicular electron Hall drift. We infer that the observed irregularities are produced through a combination of perpendicular and field-aligned relative electron-ion drifts. Features previously observed but not satisfactorily explained by perpendicular drift excitation alone can be understood in terms of field-aligned drift excitation. We conclude that the role of electron-ion field-aligned drift may be much more important than previously realized.