Formation of single and double‐headed streamers in sprite‐halo events
Formation of single and double‐headed streamers in sprite‐halo events
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精灵光环事件中单头和双头飘带的形成
DOI：
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发表时间：
2012
期刊：
影响因子：
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通讯作者：
V. Pasko
中科院分区：
文献类型：
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作者：
J. Qin;S. Celestin;V. Pasko
精灵流光源自较低电离层中的电子不均匀性，并在其光发射变得可观测之前经历显着的加速和膨胀增长。结果表明，位于精灵晕区域高海拔的电子不均匀性（可能是亚视觉的）仅转变为单头向下流光，而相应的向上流光由于雷电感应电场的快速弛豫而快速融合到精灵晕中。相比之下，位于精灵光环下边缘及其下方的不均匀性（其中高场区域持续时间明显更长）可以转变为双头流光。正如 Cummer 等人所观察到的，向上的负流光头从先前向下流光的通道中现有的明亮结构开始。 (2006)，麦克哈格等人。 (2007)、Stenbaek-Nielsen 和 McHarg (2008)，因为在低海拔地区，与这些通道相关的电子密度增强比周围电离层中预先存在的不均匀性强得多。
Sprite streamers initiate from electron inhomogeneities in the lower ionosphere and undergo significant acceleration and expansion growth before their optical emissions become observable. It is shown that electron inhomogeneities located at high altitudes in the region of sprite halo, which may be sub‐visual, only transform into single‐headed downward streamers, and corresponding upward streamers quickly merge into the sprite halo due to fast relaxation of lightning‐induced electric field. In contrast, the inhomogeneities located at and below the lower edge of the sprite halo, where a high field region persists significantly longer, can transform into double‐headed streamers. The upward negative streamer heads start from the existing bright structures in the channel of previous downward streamers as observed by Cummer et al. (2006), McHarg et al. (2007), and Stenbaek‐Nielsen and McHarg (2008) because at low altitudes, electron density enhancements associated with these channels are much stronger than in preexisting inhomogeneities in the ambient ionosphere.