人工触发闪电回击电流与通道光辐射强度关系

Return-stroke Current and Resultant Channel Luminosity in Rocket-triggered Lightning

闪电通道的光辐射强度与流过的雷电流密切相关,可利用放电电流与通道光辐射强度之间关系,通过闪电通道的发光特性研究电流特性。利用2011年和2013年国际雷电研究与测试中心人工触发闪电试验,获取了雷电流和近距离通道底部光辐射强度资料,分析了9次触发闪电回击阶段的通道底部电流和对应回击光辐射强度(相对光强)波形。39个回击电流峰值5.45~38.09 kA(几何均值13.02 kA),转移电荷量0.28~6.36 C(几何均值1.14 C),10%~90%上升时间0.16~1.19μs(几何均值0.35μs),半峰宽度5.62~61.44μs(几何均值25.51μs)。分析发现,回击电流峰值平方与对应相对光强峰值具有较强的线性关系,相对光强10%~90%上升时间大致随电流10%~90%上升时间增加而增加,未发现两者半峰宽度之间存在联系。电流脉冲转移电荷量与光对时间积分线性相关。结合回击电流峰值与相对光强峰值关系,使用相对光强波形对闪电放电的全过程进行了电流波形反演及电荷量预测,光信号反演预测得到的闪电放电电荷量误差范围为-45.33%^+42.93%,9次火箭引雷全过程的转移电荷量预测误差绝对值的平均值为31.44%,其最小误差为2.75%。

The correlation between the lightning current and the luminosity,if being found,can be adopted to investigate the characteristics of the lightning current through the corresponding light signal.In this paper,channel-base current and corresponding channel-bottom luminosity were simultaneously measured from nine rocket-triggered lightning flashes,in which all successfully were triggered at International Center for Lightning Research and Testing in 2011 and 2013.Totally,there are 39 return strokes,whose geometrical means for the peak value,the charge transfer,the 10%~90%risetime,and the half-peak width are,respectively,13.02 kA(ranging from 5.45 kA to 38.09 kA),1.14 C(ranging from 0.28 C to 6.36 C),0.35μs(ranging from 0.16μs to 1.19μs),and 25.51μs(ranging from 5.62μs to 61.44μs).The correlations of characteristic parameters between current and corresponding luminosity of return strokes are further analyzed.Linear correlations have been found not only between the current peak squared and the luminosity peak,but also between the current charge transfer and the luminosity-time integration.There is a tendency that the luminosity 10%~90%risetime increases with the increase of the current 10%~90%risetime.However,no direct correlations are found between their half-peak widths.Combined with the relations between current peak and luminosity peak,the current waveform reconstruction and charge transfer prediction are performed via the luminosity data.For the nine flashes,the discrepancy between the estimated charge transfers and their ground-truth counterparts ranges from-45.33%to+42.93%,with an averaged and a minimum absolute value being 31.44%and 2.75%,respectively.