A new lightning return stroke model based on antenna theory
A new lightning return stroke model based on antenna theory
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基于天线理论的新型雷电回击模型
DOI：
10.1029/2000jd900541
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发表时间：
2000
影响因子：
--
通讯作者：
V. Rakov
中科院分区：
文献类型：
--
作者：
R. Moini;B. Kordi;G. Rafi;V. Rakov
提出了一种基于天线理论的雷电回击过程描述方法。雷电通道近似于一个直的和垂直的微带天线与分布电阻（所谓的损耗天线）以上的一个完美的导电地面。天线在其下端由电压源馈电，从而可以指定天线输入电流，该电流表示雷电通道底部的雷电回击电流。采用时域电场积分方程（EFIE）来描述这种有耗微带天线的电磁特性。利用矩量法对电场积分方程进行数值求解，得到了电流和线电荷密度沿着天线的时空分布。这种新的天线理论（或电磁）模型与指定的电流在通道的基础上，只需要两个可调参数：回程传播速度为一个非电阻通道和通道电阻每单位长度，每个假设是恒定的（独立于时间和高度）。新模型进行了比较，四个最常用的“工程”回击模型的通道电流的时空分布，线电荷密度分布，并在不同的距离预测的电磁场。一个相当好的协议被发现与修改后的传输线模型与线性电流衰减与高度（MTLL）和与Diendorfer-Uman（DU）模型。
A new approach based on antenna theory is presented to describe the lightning returnstroke process. The lightning channel is approximated by a straight and vertical monopole antenna with distributed resistance (a so-called lossy antenna) above a perfectly conducting ground. The antenna is fed at its lower end by a voltage source such that the antenna input current, which represents the lightning return-stroke current at the lightning channel base, can be specified. An electric field integral equation (EFIE) in the time domain is employed to describe the electromagnetic behavior of this lossy monopole antenna. The numerical solution of EFIE by the method of moments (MOM) provides the time-space distribution of the current and line charge density along the antenna. This new antenna-theory (or electromagnetic) model with specified current at the channel base requires only two adjustable parameters: the return-stroke propagation speed for a nonresistive channel and the channel resistance per unit length, each assumed to be constant (independent of time and height). The new model is compared to four of the most commonly used “engineering” return-stroke models in terms of the temporal-spatial distribution of channel current, the line charge density distribution, and the predicted electromagnetic fields at different distances. A reasonably good agreement is found with the modified transmission line model with linear current decay with height (MTLL) and with the Diendorfer-Uman (DU) model.