Lightning Initiation From Fast Negative Breakdown is Led by Positive Polarity Dominated Streamers
Lightning Initiation From Fast Negative Breakdown is Led by Positive Polarity Dominated Streamers
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DOI：
10.1029/2020gl091553
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发表时间：
2021-04-28
影响因子：
5.2
通讯作者：
Pu, Yunjiao
中科院分区：
文献类型：
--
作者：
Huang, Anjing;Cummer, Steven A.;Pu, Yunjiao
正极性为主的流光前快速负击穿（FNB）和同时的正，负极性流光发展闪电启动的证据。闪电引发FNB的观测仍然是一个谜，因为闪电引发的模拟表明，在没有同时产生正流光的情况下，在原始空气中不会产生负流光。在这里，作者观察到积极的流光发展形式首先或至少同时与负流光。进一步的证据来自混合快速击穿（FB）的观测。在这种混合事件的正击穿的整体轨迹表明，正流光连续传播期间的强烈的负击穿的突发。这些观测结果表明，即使负流光占主导地位的整体甚高频（VHF）的排放量，积极和消极的流光传播同时从起始点。FB的结构和动力学的这些研究结果提供了关键的新的见解，我们了解闪电启动。
Evidence of positive polarity dominated streamers preceding fast negative breakdown (FNB) and of simultaneous positive and negative polarity streamer development in lightning initiation is reported. Observations of lightning initiation as FNB have remained a puzzle because simulations of lightning initiation have shown that negative streamers are not produced in virgin air without simultaneous positive streamers. Here, the authors observe positive streamer development forms first or at least simultaneously with negative streamers. Further evidence comes from observations of mixed fast breakdown (FB). The overall trajectory of the positive breakdown during such mixed events indicates that the positive streamers continuously propagate during the burst of strong negative breakdown. These observations indicate that even when negative streamers dominate the overall very high frequency (VHF) emissions, both positive and negative streamers are propagating simultaneously from the initiation point. These findings on the structure and dynamics of FB provide key new insight to our understanding of lightning initiation.