依据光谱研究闪电回击通道核心的特征参数

闪电回击通道核心中的大电流及其强电磁辐射是引发多种雷电灾害的主要根源.随着现代科技的飞速发展,闪电防护工作显得越为重要.为了完善闪电防护系统,需要从描述闪电回击通道核心的特征参数入手深入研究闪电通道形成和发展过程的微观物理机制.截至目前,光谱观测是获取闪电通道核心特征参数的最佳手段.2015年夏天在青海高原地区的野外试...

Study on the Characteristic Parameters of Lightning Return Stroke Channel Core Based on Spectroscopy

High current and intense electromagnetic radiation in the lightning return stroke channel core are the leading causes of many lightning disasters. With the rapid development of modern science and technology, lightning protection is becoming more and more important. In order to perfect the lightning protection system, it is necessary to investigate the microscopic physical mechanism of the lightning channel formation and development from the characteristic parameters describing the channel core. Up to now, spectral observation is the most effective means to obtain the lightning channel core characteristic parameters. In a field experiment on the Qinghai Plateau in China in the summer of 2015, a slit-less grating spectrometer assembled by a high-speed camera as a recording system was used, combined with a fast antenna ground electric field measuring instrument, the spectra of a cloud-to-ground discharge process including four return strokes and the synchronous fast electric field change information were recorded. According to the spectrum and plasma theory, the conductivity of the lightning return channel core is calculated. On this basis, the lightning electrodynamics model is used to calculate the lightning return stroke velocity, peak current, electromagnetic field across the return stroke channel core and peak power per unit length of the channel core. The results show that the return stroke velocity is in the range of (1.2～2.3)×108 m·s-1, and the maximum values of the axial electric field, radial electric field and magnetic induction intensity across the return stroke channel core are in the range of (1.42～1.74)×105 V·m-1,(8.22～9.99)×108 V·m-1 and 1.51～2.83 T, respectively. When the peak current is in the range of 7.52～24.05 kA, the peak power of the return stroke channel core is in the range of (0.63～1.92)×109 W·m-1. In addition, the correlations between the electrical conductivity, the initial electric field peak value, the return stroke velocity and the peak current and the peak power are analyzed, it is found that the peak current and peak power has a good linear relationship. The results can provide a reference for further exploring the microscopic physical mechanism of the formation and development of the lightning return stroke channel.