A study of lightning flash initiation prior to the first initial breakdown pulse
A study of lightning flash initiation prior to the first initial breakdown pulse
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DOI：
10.1016/j.atmosres.2018.10.013
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发表时间：
2019-03
影响因子：
5.5
通讯作者：
T. Marshall;S. Bandara;N. Karunarathne;S. Karunarathne;I. Kolmašová;R. Siedlecki;M. Stolzenburg
中科院分区：
文献类型：
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作者：
T. Marshall;S. Bandara;N. Karunarathne;S. Karunarathne;I. Kolmašová;R. Siedlecki;M. Stolzenburg
本研究探讨了两个云内（IC）和两个云对地（CG）闪电的启动使用电场变化（FA）传感器和VHF（LogRF）传感器位于牛津，密西西比，美国附近的七个站点。对于每次闪光，初始事件在LogRF数据中产生脉冲，并在FA数据中启动初始E变化（IEC）。初始LogRF脉冲的功率<1 W，持续时间约为1 μs。在每个IEC期间出现大量LogRF脉冲;这些脉冲的持续时间≤3 μs。每次IEC期间发生的FA脉冲较少;这些脉冲的持续时间≤7 μs。在每个IEC期间，少数LogRF脉冲与FA脉冲重合，并且大多数这样的脉冲对增强IEC;没有这样的重合对，没有IEC增强事件发生。每次闪光有1或2个IEC增强事件后不久的启动事件和1或2个增强事件前不久的第一个经典的初始击穿（IB）脉冲发生。两次IC闪光的点偶极矩和IEC持续时间分别为（-520Cm，620 μs）和（-770Cm，1790 μs），两次CG闪光的点偶极矩和IEC持续时间分别为（9 Cm，124 μs）和（36 Cm，130 μs）。我们推测，LogRF事件是积极的电晕流光，增强事件发生时，一个新的流光延长了以前的流光路径，这个过程中的闪光启动开发了一个新生的通道所需的负击穿的IB脉冲。
This study examines the initiation of two intracloud (IC) and two cloud-to-ground (CG) lightning flashes using electric field change (FA) sensors and VHF (LogRF) sensors located at seven sites near Oxford, Mississippi, USA. For each flash the initiating event caused a pulse in the LogRF data and started an Initial E-Change (IEC) in the FA data. The initiating LogRF pulses had powers <1 W and durations of ~1 μs. Numerous LogRF pulses occurred during each IEC; these pulses had durations ≤3 μs. Fewer FA pulses occurred during each IEC; these pulses had durations of ≤7 μs. During each IEC, a few of the LogRF pulses were coincident with a FA pulse, and most such pairs of pulses enhanced the IEC; no IEC enhancing events occurred without such a coincident pair. Each flash had 1 or 2 IEC enhancing events soon after the initiating event and 1 or 2 enhancing events shortly before the first classic initial breakdown (IB) pulse occurred. The point dipole moments and durations of IECs of the two IC flashes were (–520C m, 620 μs) and (–770C m, 1790 μs) and for the two CG flashes were (9C m, 124 μs) and (36C m, 130 μs). We speculate that the LogRF events were positive corona streamers, that enhancing events occurred when a new streamer extended a previous streamer path, and that this process during the flash initiation developed a nascent channel needed for the negative breakdown of the IB pulses.