闪电M分量光谱特征及通道温度和电子密度特性  

Spectral features,temperature and electron density properties of lightning M-component

作　　者：王雪娟 许伟群 王海通 杨静[2] 袁萍 张其林[1] 化乐彦 张袁瞰 Wang Xue-Juan;Xu Wei-Qun;Wang Hai-Tong;Yang Jing;Yuan Ping;Zhang Qi-Lin;Hua Le-Yan;Zhang Yuan-Kan(Key Laboratory of Meteorological Disaster,Ministry of Education(KLME),Joint International Research Laboratory of Climate and Environment Change(ILCEC),Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD),Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration,Nanjing University of Information Science&Technology,Nanjing 210044,China;Key Laboratory of Middle Atmosphere and Global Environment Observation(LAGEO),Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029,China;Key Laboratory of Atomic and Molecular Physics&Functional Materials of Gansu Province,College of Physics and Electronic Engineering,Northwest Normal University,Lanzhou 730070,China)

机构地区：[1]南京信息工程大学气象灾害教育部重点实验室,气候与环境变化国际合作联合实验室,气象灾害预报预警与评估协同创新中心,中国气象局气溶胶与云降水重点开放实验室,南京210044 [2]中国科学院大气物理研究所,中层大气和全球环境探测重点实验室,北京100029 [3]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,兰州730070

出　　处：《物理学报》2021年第9期423-431,共9页Acta Physica Sinica

基　　金：江苏省自然科学基金(批准号:BK20180805);国家自然科学基金(批准号:42005065);南京信息工程大学人才启动基金(批准号:2017r065);南京信息工程大学大学生创新项目(批准号:201910300133Y)资助的课题;中国科学院中层大气和全球环境探测重点实验室(LAGEO)开放课题(批准号:LAGEO-2019-07);中国气象科学院灾害天气国家重点实验室开放课题(批准号:2020LASW-B14)。

摘　　要：利用无狭缝光栅摄谱仪记录的一次闪电首次回击后3个M分量的光谱资料,分析了其光谱特征.并结合等离子体理论,首次计算了闪电M分量内部核心通道和周围电晕层通道的温度和电子密度.研究了这两个物理量沿通道的变化特性,并与相应回击放电进行了对比.结果表明:闪电M分量的光谱特征相比回击的光谱特征有明显差异, M分量通道的光辐射主要来自红外波段的光谱线. M分量放电过程中内部电流核心通道的温度可达40000 K,电子密度数量级为10~(18) cm~(–3).周围电晕层通道的温度为20000 K左右,电子密度比核心通道的电子密度小一个数量级. M分量内部核心通道的温度随通道高度的增加而减小,周围电晕层通道的温度随通道高度的增加而增大.在内部核心通道,电子密度随高度基本保持不变.在周围电晕层通道,通道顶端光强明显增大的两个M分量其电子密度随通道高度的增加而增大,顶端光强增加较弱的一个M分量其电子密度随通道高度基本保持不变.而相应的回击放电,其内部电流核心通道和外围电晕层通道的温度均随通道高度的增加而增大,电子密度均沿通道基本保持不变.Using the spectra of the three M-components following a first return stroke recorded by a slitless spectrograph,the spectral features of the M-components are analyzed.Combining with plasma theories,the temperatures and the electron densities of the M-components in the channel core and outer corona sheath are calculated.The variations along the channel of these two parameters are studied,and compared with the corresponding return stroke.The results show that the spectra of the M-components are different from the spectrum of the return stroke.The optical radiation of the M-component is primarily from the spectral lines in infrared waveband.The temperature of the M-component in the channel core can reach 40000 K.The electron density of the M-component in the channel core is on the order of 1018 cm–3.The temperature of the Mcomponent in the external corona sheath is about 20000 K.The electron density of the M-component in the external corona sheath is on the order of 1017 cm–3.The temperature of the M-component in the channel core decreases with height increasing,while that in the external corona sheath increases with channel height increasing.The electron density of the M-component in the channel core basically does not change with channel height.Whereas,the electron densities in the external corona sheath for two M-components with hard light at the upper end of the channel increase with channel height increasing,and the electron density for one Mcomponent with weak light at upper end of the channel basically does not change with the channel height.By comparison,the temperature in the core channel and in the external corona sheath of the corresponding return stroke both increase with channel height.The electron density in the core channel and in the external corona sheath of the corresponding return stroke both basically remain constant along the channel.

关 键 词：闪电M分量 核心通道 电晕层 温度和电子密度 

分 类 号：O433[机械工程—光学工程]