Patch Size Evolution During Pulsating Aurora
Patch Size Evolution During Pulsating Aurora
复制标题
脉动极光期间的斑块大小演变
DOI：
10.1029/2018ja026423
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
H. Sundberg
中科院分区：
文献类型：
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作者：
N. Partamies;K. Bolmgren;E. Heino;N. Ivchenko;J. Borovsky;H. Sundberg
我们报告在脉动极光事件的补丁大小的减少和增加的趋势。在芬兰斯堪的纳维亚的拉普兰地区，大约150个脉动极光事件已经成功地分析了它们的平均斑块大小，总斑块面积和斑块数量作为事件时间的函数，通常为1-2小时。除了事件减少和增加的平均斑块大小的演变过程中的脉动极光，事件没有大小的趋势和事件间歇性增加和减少斑块大小的趋势也被发现，在这项研究中，我们分析了一个子集的事件的平均和总斑块大小系统地增加或减少。斑块大小增加趋势的事件没有经历峰值发射高度的降低，这是以前与脉动极光降水的行为。此外，随着斑块大小增加的事件具有更短的寿命，并且在地球同步轨道上的亚暴注入高能电子是斑块大小减小的事件的两倍。有一半的事件与增加补丁大小发生在亚暴扩张阶段，而大多数（64%）的补丁大小减少发生在恢复阶段。这些发现表明，脉动极光的视觉外观可以用作脉动极光能量沉积到大气中的指示。
We report both decreasing and increasing trends in the patch sizes during pulsating aurora events. About 150 pulsating auroral events over the Fennoscandian Lapland have been successfully analyzed for their average patch size, total patch area, and number of patches as a function of event time, typically 1–2 hr. An automatic routine has been developed to detect patches in the all‐sky camera images. In addition to events with decreasing and increasing average patch size evolution over the course of the pulsating aurora, events with no size trends and events with intermittently increasing and decreasing patch size trends were also found. In this study, we have analyzed a subset of events for which the average and total patch size systematically increase or decrease. The events with increasing patch size trend do not experience a decrease in the peak emission height, which was previously associated with the behavior of pulsating aurora precipitation. Furthermore, the events with increasing patch sizes have shorter lifetimes and twice as many substorm‐injected energetic electrons at geosynchronous orbit as the events with decreasing patch sizes. Half of the events with increasing patch sizes occur during substorm expansion phases, while a majority (64%) of the ones with decreasing patch sizes take place during the recovery phase. These findings suggest that the visual appearance of pulsating aurora may be used as an indication of the pulsating aurora energy deposition to the atmosphere.