云地闪电首次回击通道温度与电子密度的空间演化  

Spatial Evolution of Temperature and Electron Density in First Return Stroke Channel of Cloud-to-Ground Lightning

作　　者：石花园 薛思敏[1] 覃金 安婷婷 袁丽珍 张凡 Shi Huayuan;Xue Simin;Qin Jin;An Tingting;Yuan Lizhen;Zhang Fan(School of Mathematics and Physics,Lanzhou Jiaotong University,Lanzhou 730070,Gansu,China;College of Physics and Electronic Engineering,Key Laboratory of Atomic and Molecular Physics and Functional Materials of Gansu Province,Northwest Normal University,Lanzhou 730070,Gansu,China)

机构地区：[1]兰州交通大学数理学院,甘肃兰州730070 [2]西北师范大学物理与电子工程学院,甘肃省原子分子物理与功能材料重点实验室,甘肃兰州730070

出　　处：《光学学报》2024年第18期438-447,共10页Acta Optica Sinica

基　　金：兰州市人才创新创业项目(2023-3-103)。

摘　　要：利用无狭缝光谱仪得到的4个云地闪电首次回击的光谱资料,分析了回击光谱的结构特征。结合等离子体理论,通过多谱线法计算了核心通道和外围电晕鞘通道的温度,根据谱线的Stark加宽方法得到电子密度。研究了回击通道温度和电子密度沿通道的演化特性;探讨了核心通道温度与氮离子线相对强度比的关系。结果表明:核心通道的温度和电子密度比电晕鞘通道高,且核心通道的温度和电子密度沿通道呈衰减、略上升和基本不变3种趋势。电晕鞘通道温度随通道高度的升高变化不明显,在20000 K左右起伏,电子密度沿通道呈略下降和基本不变两种趋势,其沿通道的衰减比核心通道的衰减较缓慢。此外,回击光谱中NII 500.5 nm和568.0 nm谱线的相对强度的比值与核心通道温度存在较强的相关性。Objective Lightning is a discharge phenomenon that involves high currents and strong electromagnetic radiation.The peak temperature of the discharge channel can reach up to 30000 K due to the high current of the return stroke process.The channel’s air becomes ionized,generating free electrons and ions and creating a plasma channel.Lightning activity in the Qinghai-Tibet Plateau has increased due to global warming.The strong currents in the lightning discharge channel can cause significant damage to buildings,humans,and livestock on the ground.Therefore,lightning hazards and protection have been of key concern.Spectroscopic diagnosis of lightning plasma has become an essential tool for measuring the lightning discharge process due to the further study of its physical properties.The quantitative analysis of the spectra enables the calculation of the basic parameters of the lightning channel’s physical characteristics.Currently,there are studies available on the evolution of temperature and electron density along the lightning return stroke channel,but fewer studies on the spatial evolution characteristics of the temperatures and electron densities of the core channel and the peripheral corona sheath channel.The spatial evolutions of temperatures and electron densities in the core and peripheral corona sheath channels are closely related to the distribution of lightning discharge energy and the transmission characteristics of the discharge current.We use a slitless spectrograph to obtain the spectral information from the first return strokes of four lightning.The temperatures and electron densities of the core channel and the peripheral corona sheath channel are calculated and investigated to characterize the variation of the temperature and electron density along the discharge channel.Furthermore,we explore the relationship between the core channel temperature and the relative intensity ratio of the nitrogen ion line.The study is expected to provide some clues and implications for the exploration of the energy

关 键 词：闪电光谱 通道温度 电子密度 Stark加宽 

分 类 号：O433.4[机械工程—光学工程]