雷暴云下地闪先导通道中的电荷分布

A Numerical Study on Charge Distribution in Leader Channel of Cloud-to-Ground Lightning Discharges

利用不荷电双向传输先导模型 ,考虑近地面空间电荷层对地表垂直电场的影响和云电荷的转移 ,在一定的雷暴云电荷结构假定下 ,对地闪先导通道中的电荷分布进行了模拟计算。结果表明 ,先导接地瞬间通道上的平均电荷密度约为 1.5× 10 - 3C·m- 1 ,通道中的总电荷量约为 14 .8C ,其中平均感应电荷密度仅占总电荷密度的 2 0 % ,约为 0 .34× 10 - 3C·m- 1 。

A consistent physical model that describes the relationship between cloud charges and lightning was produced and used to simulate the charge density in the leader channel based on the bi directional leader model. The results indicated that the total charge in the leader channel increases when it closes to ground. It was found that the average charge density in the leader channel just before it reaches the ground is 1.5×10 -3 C·m -1 , and the total charge in the leader channel is 14.8 C. The induced charge density in the leader channel is 0.34×10 -3 C·m -1 , which takes about 20% of the total charge in the leader channel, indicatingthat the most common way by which charges stored in the leader channel was the transporting of cloud charges.