空中触发闪电的下行先导及其接地行为

１９９６年夏季在江西南昌附进行的人工触发闪电野外实验中，用新开发的不接地的火箭－导线技术成功地在雷暴云下的负环境电场中触发了云对地产偿电。我们用一套成像率为１０００幅／秒的高速数字化摄像系统对下行负先导进行了观测。

THE DOWNWARD-MOVING LEADER OF THE LIGHTNING FLASH TRIGGERED AT ALTITUDE AND ITS BEHAVIOR IN CONNECTING TO THE GROUND

In the field experiment of artificially triggering lightning conducted near Nanchang, Jiangxi in the summer of 1996, 3 lightning flashes were successfully triggered by use of newly-developed technique with ungrounded rocket-wire system in negative ambient electric field of thunderclouds. A high-speed digital camera with 1 000F/s framing rate was used for the observation. Data analysis revealed the characteristics of the initiation, propagation and connection to the ground of the downward-moving negative leader, which progressed at a lower speed and showed zigzag, branching on its way to the ground, and finally terminated on the tip of a 4m high, well grounded lightning rod. The current density along the channel was not uniform on the moment when the downward leader touched the ground. A physical model of leader inception and propagation in altitude triggered lightning was presented through case analyses.