The Mechanism of the Origin and Development of Lightning From Initiating Event to Initial Breakdown Pulses (v.2)
The Mechanism of the Origin and Development of Lightning From Initiating Event to Initial Breakdown Pulses (v.2)
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DOI：
10.1029/2020jd033191
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发表时间：
2020-11-27
影响因子：
4.4
通讯作者：
Stolzenburg, Maribeth
中科院分区：
文献类型：
--
作者：
Kostinskiy, Alexander Yu;Marshall, Thomas C.;Stolzenburg, Maribeth
本文根据近年来的实验结果，定性地描述了一种可能的机制（简称“机制”），它涵盖了闪电引发的主要阶段，即在引发事件之前开始，包括引发事件，然后是初始电场变化（IEC），然后是最初的几个初始击穿脉冲（IBP）。该机制假设在平均电场E > 0.3 MV/（m center dot atm）的近似1 km（3）的区域中发生引发，由于湍流，该区域包含许多近似10（-4）-10（-3）m（3）的小“E次体积”，其中E >= 3 MV/（m center dot atm）。该机制允许由两种观察到的事件中的任一种引发闪电：高功率，甚高频（VHF）事件，如窄双极事件或弱VHF事件。根据该机制，这两种类型的引发事件都是由一组相对论性逃逸电子雪崩粒子（其中初始电子是广泛的空气簇射的次级粒子）穿过许多E-th体积引起的，从而导致几乎同时发射许多正流光闪光。由于电离加热的不稳定性，不寻常的等离子体形成（UPFs）出现沿着流光的轨迹。在IEC期间，这些UPFs联合收割机组合成热等离子体通道的三维（3-D）网络，导致其观察到的弱电流。随后，这些热等离子体通道的3D网络中的两个（或更多个）的后续发展和组合会导致第一次IBP。当另一个3-D热等离子体通道网络与由先前的IBP引起的网络链结合时，引起每个后续的IBP。
Based on experimental results of recent years, this article presents a qualitative description of a possible mechanism (termed the Mechanism) covering the main stages of lightning initiation, starting before and including the initiating event, followed by the initial electric field change (IEC), followed by the first few initial breakdown pulses (IBPs). The Mechanism assumes initiation occurs in a region of similar to 1 km(3) with average electric field E > 0.3 MV/(m center dot atm), which contains, because of turbulence, numerous small "E-th volumes" of similar to 10(-4)-10(-3) m(3) with E >= 3 MV/(m center dot atm). The Mechanism allows for lightning initiation by either of two observed types of events: a high-power, very high frequency (VHF) event such as a Narrow Bipolar Event or a weak VHF event. According to the Mechanism, both types of initiating events are caused by a group of relativistic runaway electron avalanche particles (where the initial electrons are secondary particles of an extensive air shower) passing through many E-th volumes, thereby causing the nearly simultaneous launching of many positive streamer flashes. Due to ionization-heating instability, unusual plasma formations (UPFs) appear along the streamers' trajectories. These UPFs combine into three-dimensional (3-D) networks of hot plasma channels during the IEC, resulting in its observed weak current flow. The subsequent development and combination of two (or more) of these 3-D networks of hot plasma channels then causes the first IBP. Each subsequent IBP is caused when another 3-D network of hot plasma channels combines with the chain of networks caused by earlier IBPs.