Activation of Abundant Recoil Leaders and Their Promotion Effect on the Negative-End Breakdown in an Intracloud Lighting Flash
Activation of Abundant Recoil Leaders and Their Promotion Effect on the Negative-End Breakdown in an Intracloud Lighting Flash
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云内闪电中丰富反冲先导的激活及其对负端击穿的促进作用
DOI：
10.1029/2021gl096846
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发表时间：
2022-01-16
影响因子：
5.2
通讯作者：
Wang, Dongfang
中科院分区：
文献类型：
--
作者：
Jiang, Rubin;Yuan, Shanfeng;Wang, Dongfang
利用同步高速成像、电磁场变化和辐射源映射技术研究了一次独特的具有多个正前导分支从同一点展开的独一无二的声内闪电。一条正向引导者的通道从云层中伸出，在引导者尖端前方数十米处诱导出双向发光段。它们导致了一种小规模的依附，其中多个渠道相继出现并向不同的方向传播。正向先导的传播模式经历了从稳定顺畅的通道延伸到活跃发展的明显转变，并伴随着频繁的反冲先导，归因于云内活动诱发的脉冲电流波的到来。我们发现确凿的证据表明，长反冲先导通过规则的电磁脉冲序列激活了负端击穿。揭示了来自相关通道相反两端的来回交互作用。简单的语言摘要反冲先导沿着最初由正向击穿形成的预条件通道传播。它是雷电通道重新启动和维护的关键方式，与雷电通道的衰减和切断密切相关。它的发生导致了随后的回击、M分量和K事件等各种闪电放电过程。对后坐引头的认识对于理解闪电放电和传播的本质具有重要意义。本文通过同时进行高速视频观测、电磁场探测和闪电辐射源测绘，揭示了云内活动诱发的强流波到达正向引信通道末端可以促进反冲引信的丰硕生产。反过来，一些长后坐力领导者也会激活相反的负面击穿。在相对两端之间的相互作用期间，发现了变暗的通道的来回重新照明。这些发现为后坐引头的形成及其对其他击穿过程的影响提供了新的见解。
A unique intracloud (IC) lightning flash with multiple positive leader branches spreading out from the same point is studied using simultaneous high-speed images, electromagnetic (EM) field changes, and radiation source mapping. A channel of the positive leader protruded from the cloud and induced a bidirectional luminous segment at tens of meters ahead of the leader tip. They led to a small-scale attachment where multiple channels successively emerged and propagated toward diverse directions. The propagation mode of the positive leader experienced a noticeable transition from stable and smooth channel extension to active development accompanied with frequent recoil leaders, attribute to the arrival of an impulsive current wave induced by the in-cloud activity. We find solid evidence that long recoil leader activated the negative-end breakdown with a regular EM pulse train. The back-and-forth interaction from the opposite ends of the associated channel is revealed.Plain Language Summary Recoil leader propagates along the preconditioned channel that is originally formed by positive breakdown. It acts as a critical manner of lightning channel reactivation and maintenance, and is closely related to the lightning channel decaying and cutoff. Its occurrence results in various lightning discharge processes such as subsequent return stroke, M component, and K event. The knowledge of recoil leader is of great significance to understanding the nature of lightning discharge and propagation. In this paper, by conducting simultaneous high-speed video observation, electromagnetic field detection, and lightning radiation source mapping, we reveal that the fruitful production of recoil leaders can be facilitated by the arrival of an in-cloud-activity-induced strong current wave to the positive leader channel extremity. In turn, some long recoil leaders would also activate the opposite-end negative breakdown. Back and forth re-illumination of dimmed channel is discovered during the interaction between the opposite ends. These findings provide new insight into the recoil leader formation and its effect on other breakdown processes.