Abstract The altitude rocket-and-wire technique was used to trigger lightning to strike a 30-m-high communication tower. A comprehensive dataset was obtained, including discharge current and electromagnetic-field changes, as well as high-speed video images. An attachment process with an abnormal circuitous S-shaped connection channel was observed between the lower extremity of the triggering wire and the tower top, with a total channel length of 25.3 m, which was much longer than the direct connection channel of 13.0 m. The downward negative leader from the triggering wire and the upward connecting positive leader from the tower top “missed” each other by a vertical distance of 4.1 m before turning to the horizontal direction and eventually completing the breakthrough phase. The attachment process produced a sharp current pulse with a duration of 19 μs and a peak of 11.6 kA, transiently promoting the upward positive leader development from the upper extremity of the triggering wire. The simulation of the background electric field indicated that the electric field surrounding the tips of the initial leaders did not involve a dominant direction with pronounced larger intensity. The leader streamer/corona zones with a divergent feature resulted in directional uncertainty for the initial steps. As the leaders developed and the associated streamer/corona zones expanded, the attraction effect was enhanced and the leaders turned to the horizontal direction. The common streamer zone (CSZ) developed when the gap between the leaders was about 8 to 9 m, resulting in the occurrence of the breakthrough phase and accomplishment of the attachment. For the last return stroke, the long interstroke interval facilitated channel cooling and a decrease in conductivity. This promoted the occurrence of a dart-stepped leader instead of dart leader, and led to the alteration of the attachment route from an S-shaped channel to a direct connection channel.

中文翻译：

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高度触发闪电击中 30 米高塔的迂回附着过程

摘要 采用高空火箭线技术触发雷击30米高的通信塔。获得了全面的数据集，包括放电电流和电磁场变化，以及高速视频图像。在触发线下端与塔顶之间观察到异常迂回的S形连接通道的附着过程，通道总长度为25.3 m，远长于13.0 m的直接连接通道。触发线向下的负先导与塔顶向上连接的正先导“错失”了4.1 m的垂直距离，然后转向水平​​方向并最终完成了突破阶段。附着过程产生了一个持续时间为 19 μs 和峰值为 11.6 kA 的尖锐电流脉冲，瞬时促进了触发线上端向上正向先导的发展。背景电场的模拟表明，初始前导尖端周围的电场不涉及具有明显更大强度的主导方向。具有发散特征的前导流光/日冕区导致初始步骤的方向不确定性。随着领导者的发展和相关的流光/日冕区的扩大，吸引效应增强，领导者转向水平方向。共同拖缆带（CSZ）在领导者之间的差距约为 8 至 9 m 时发展，导致突破阶段的发生和执着的成就。对于最后一个回程，较长的冲程间隔促进了通道冷却和电导率的降低。这促进了飞镖梯级引线而不是飞镖引线的出现，并导致连接路径从 S 形通道改变为直接连接通道。