On the Origin of Two Types of Current Pulses Observed During the Initial Stage of Upward Lightning
We analyzed high-speed video images and corresponding current records for eight upward lightning flashes initiated by the Peissenberg tower (160 m) in Germany.These flashes contained a total of 33 measurable initial stage (IS) current pulses, which are superimposed on steady IS currents.Seven IS pulses had relatively short (< 8 μs) 10-to-90％ risetimes and 26 IS pulses had relatively long (> 8 μs) risetimes.Six (86％) of seven IS current pulses with shorter risetimes each developed in a newly-illuminated branch, and 25 (96％) of 26 IS pulses with longer risetimes occurred in already luminous (current-carrying) channels.These results support the hypothesis that longer risetimes are indicative of the M-component mode of charge transfer to ground, while shorter risetimes are associated with the leader/return stroke mode.Similar results were obtained for M-component pulses that are superimposed on continuing currents following return-stroke pulses.
Denis Flache Vladimir A. Rakov Fridolin H. Heidler Wolfgang J. Zischank Rajeev Thottappillil
University of Florida,Gainesville,USA University of Federal Armed Forces,Munich,Germany University of Florida,Gainesville,USA University of Federal Armed Forces,Munich,Germany Royal Institute of Technology (KTH),Stockholm,Sweden
国际会议
成都
英文
1-5
2011-11-01（万方平台首次上网日期，不代表论文的发表时间）