The evolution of discharge current and channel radius in cloud-to-ground lightning return stroke process
The evolution of discharge current and channel radius in cloud-to-ground lightning return stroke process
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云地闪电回击过程中放电电流和通道半径的演化
DOI：
10.1016/j.atmosres.2017.05.001
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发表时间：
2017-09-15
影响因子：
5.5
通讯作者：
Zhao, Yanyan
中科院分区：
文献类型：
--
作者：
Fan, Tingting;Yuan, Ping;Zhao, Yanyan
利用时间分辨率为110 μ s的无狭缝高速摄谱仪，获得了两次多次回击的负云地闪放电过程的光谱。结合同步电性观测资料和理论计算，分析了回击过程的物理特征。验证了放电电流与光谱中离子线强度之间的正相关性，并基于这一特征研究了4次回击过程中的电流演化特征。结果表明，用多点拟合法估算的峰值电流到半峰值的时间约为101 μ s ~ 139 μ s。四个回程通道的每单位长度中的焦耳热在10（5）J/m-10（6）J/m的数量级。电弧放电通道半径与放电电流呈正相关，电流越大，通道半径越大。此外，弧芯通道半径在回击过程中的演变规律与放电电流峰值后的变化趋势一致。与电流的衰减相比，温度下降得更慢。
The spectra of two negative cloud-to-ground lightning discharge processes with multi-return strokes are obtained by a slit-less high-speed spectrograph, which the temporal resolution is 110 mu s. Combined with the synchronous electrical observation data and theoretical calculation, the physical characteristics during return strokes process are analysed. A positive correlation between discharge current and intensity of ionic lines in the spectra is verified, and based on this feature, the current evolution characteristics during four return strokes are investigated. The results show that the time from peak current to the half-peak value estimated by multi point-fitting is about 101 mu s-139 mu s. The Joule heat in per unit length of four return strokes channel is in the order of 10(5) J/m-10(6) J/m. The radius of arc discharge channel is positively related to the discharge current, and the more intense the current is, the greater the radius of channel is. Furthermore, the evolution for radius of arc core channel in the process of return stroke is consistent with the change trend of discharge current after the peak value. Compared with the decay of the current, the temperature decreases more slowly.