Observations of narrow bipolar events reveal how lightning is initiated in thunderstorms.
Observations of narrow bipolar events reveal how lightning is initiated in thunderstorms.
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对狭窄的双极事件的观察结果表明，雷暴是如何在雷暴中启动的。
DOI：
10.1038/ncomms10721
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发表时间：
2016-02-15
影响因子：
16.6
通讯作者：
Zhang Y
中科院分区：
文献类型：
--
作者：
Rison W;Krehbiel PR;Stock MG;Edens HE;Shao XM;Thomas RJ;Stanley MA;Zhang Y
闪电研究中一个长期存在但基本的问题是，在没有物理导体的情况下，闪电是如何在风暴中引发的。这个问题一直围绕着这样一个问题，即放电是仅仅由传统的介质击穿引发的，还是涉及相对论性逃逸电子过程。在这里，我们报告了一种相对未知的放电类型的观察，称为快速正击穿，这是高功率放电的原因，称为窄双极事件。击穿被发现有广泛的强度，是众多的闪电放电的起始事件。它似乎是纯电介质的性质，并在局部强电场区域的正流光系统组成。它在拖缆的起始位置处引发负击穿，这导致随后的闪光。观测结果表明，许多或可能所有的闪电都是由快速正击穿引发的。 闪电是如何在风暴中产生的一直是一个长期存在的基本问题。在这里，作者报告了一种以前未被认识到的放电类型的观察结果，称为快速正击穿，它被发现在风暴中引发了许多甚至可能是所有的闪电放电。
A long-standing but fundamental question in lightning studies concerns how lightning is initiated inside storms, given the absence of physical conductors. The issue has revolved around the question of whether the discharges are initiated solely by conventional dielectric breakdown or involve relativistic runaway electron processes. Here we report observations of a relatively unknown type of discharge, called fast positive breakdown, that is the cause of high-power discharges known as narrow bipolar events. The breakdown is found to have a wide range of strengths and is the initiating event of numerous lightning discharges. It appears to be purely dielectric in nature and to consist of a system of positive streamers in a locally intense electric field region. It initiates negative breakdown at the starting location of the streamers, which leads to the ensuing flash. The observations show that many or possibly all lightning flashes are initiated by fast positive breakdown. How lightning is initiated inside storms has been a long-standing and fundamental question. Here, the authors report observations of a previously unrecognized type of discharge, called fast positive breakdown, that is found to initiate many and potentially all lightning discharges in storms.