Advanced Research Projects Agency Long‐Range Tracking and Instrumentation Radar data acquired during the NASA Waves and INstabilities from a Neutral DYnamo (WINDY) sounding rocket campaign on Kwajalein Atoll in late August and September 2017 are analyzed to study the development of postsunset F ‐region ionospheric plasma density irregularities associated with equatorial spread F (ESF) conditions. Unstable conditions existed on nine of ten observing nights during the campaign. The first indication of instability onset each night was a patchy layer of coherent scatter in the bottomside/valley region. Patchy bottom‐type layers are telltales of plasma convective instability driven by vertical current in the F region associated with bottomside shear flow. The resulting flow evolves rapidly into fully developed instability through a bootstrapping process. Sometimes, the resulting topside depletions exhibited large‐scale structuring with a spatial scale too large to be associated with the preferred scale for plasma instability. We examine incoherent scatter observations of the background ionospheric morphology prior to the appearance of bottom‐type layers and find that a small degree of large‐scale bottomside structuring is sometimes present. Numerical simulations suggest that this structuring can act as a seed and provide the initial conditions necessary to account for the clustering of the topside plumes that emerge later.

中文翻译：

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WINDY工程在夸贾林上空的日落后赤道电离层不稳定性的雷达调查

美国高级研究计划局（NASA）于2017年8月下旬和2017年9月在夸贾林环礁的中性DYnamo（WINDY）探空火箭战役中从NASA波浪和不稳定性中获取的远程跟踪和仪器雷达数据进行了分析，以研究后置F区电离层的发展与赤道扩散F（ESF）条件相关的血浆密度异常。竞选期间十个观察之夜中有九个晚上存在不稳定的状况。每天晚上开始出现不稳定性的第一个迹象是在底侧/谷地区域出现了片状的相干散射层。底部不整齐的层是由F中的垂直电流驱动的等离子体对流不稳定性的故事与底侧剪切流有关的区域。最终的流程通过自举过程迅速演变为完全不稳定的状态。有时，所产生的上层耗尽显示出大规模的结构化，其空间尺度太大，无法与血浆不稳定的首选尺度相关联。我们检查了底部类型层出现之前背景电离层形态的非相干散射观测结果，发现有时会出现少量大规模的底部结构。数值模拟表明，这种结构可以起到种子的作用，并提供必要的初始条件，以说明后来出现的顶羽聚集。