The relationship between pulsating auroras observed from the ground and energetic electrons and plasma density measured at geosynchronous orbit
The relationship between pulsating auroras observed from the ground and energetic electrons and plasma density measured at geosynchronous orbit
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从地面观测到的脉动极光与在地球同步轨道上测量的高能电子和等离子体密度之间的关系
DOI：
10.1029/95ja01756
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发表时间：
1995
影响因子：
--
通讯作者：
Tatsundo Yamamoto
中科院分区：
文献类型：
--
作者：
R. Nemzek;R. Nakamura;D. Baker;R. D. Belian;D. McComas;M. Thomsen;Tatsundo Yamamoto
我们对脉动极光事件的地面全天视频记录与高能电子和低能等离子体的磁共轭地球同步轨道测量进行了比较。大规模的脉动事件被发现与亚暴电子注入密切相关。对于大多数事件，只有上限可用于等离子体密度，即≤1-2 cm−3。我们无法找到等离子体密度和脉动之间的任何明确的依赖关系。然而，有小，快速波动的密度有明显的空间尺度类似的个人脉动极光补丁。这些同时测量的电子通量，等离子体密度，和脉动周期应使用在约束理论治疗的脉动极光问题。我们发现Demekhov和Trakhtengerts（1994）预测的最小等离子体密度和等离子体密度梯度的条件可能不被地球同步轨道数据所支持，但他们对最小高能电子密度的预测是支持的。Davidson和Chiu（1987）对等离子体密度和电子通量的最小变化的预测似乎也得到了支持。这些数据表明，控制脉动发生在特定区域的主要因素可能是亚暴注入电子到达共轭赤道。这一结论可以为通过观测脉动极光来绘制亚暴注入区的可见磁图提供依据。
We present comparisons of ground-based all-sky video recordings of pulsating auroral events and magnetically conjugate geosynchronous orbit measurements of high-energy electrons and low-energy plasma. The large-scale pulsation events were found to be closely tied to substorm electron injections. For most events, only upper limits were available for the plasma density, which was ≤1–2 cm−3. We were unable to find any clear dependence between the plasma density and the pulsations. There were, however, small, rapid fluctuations in the density which had apparent spatial scales similar to those of individual pulsating auroral patches. These simultaneous measurements of the electron flux, plasma density, and pulsation period should be of use in constraining theoretical treatments of the pulsating aurora problem. We find that the conditions for minimum plasma density and plasma density gradient predicted by Demekhov and Trakhtengerts (1994) may not be supported by the geosynchronous data but that their prediction for minimum energetic electron density is supported. Predictions by Davidson and Chiu (1987) of the minimum change in plasma density and electron flux also seem to be supported. The data indicate that the principal factor controlling the onset of pulsations over a particular area may be the arrival of substorm-injected electrons at the conjugate equator. This conclusion could provide the basis for a visible magnetic mapping of the substorm injection region through observations of the pulsating aurora.