Observations of the initial stage of a rocket‐and‐wire‐triggered lightning discharge. Issue 9 (9th May 2017)

• Record Type: Journal Article
• Authors: Zhang, Yang; Krehbiel, Paul R.; Zhang, Yijun; Lu, Weitao; Zheng, Dong; Xu, Liangtao; Huang, Zhigang
• Is Part Of: Geophysical research letters. Volume 44:Issue 9(2017)
• Page Start: 4332
• Page End: 4340
• Publication Date: 2017-05-09
• Subjects: triggered lightning -- precursor pulses -- upward positive leader -- electrical breakdown -- broadband interferometer; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1002/2017GL072843
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: Observations have been obtained of the initial stage of a rocket‐and‐wire‐triggered lightning flash with a high‐resolution broadband VHF interferometer. The discharge produced 54 precursor current pulses (PCPs) over 883 ms during the rocket's ascent. The interferometer observations show that the PCPs were produced by breakdown at the ascending tip of the rocket, and that individual PCPs were produced by weak upward positive breakdown over meters‐scale distances, followed by more energetic, fast downward negative breakdown over several tens of meters distance. The average propagation speeds were ~5 × 10 6 m s −1 and ~3 × 10 7 m s −1, respectively. The sustained upward positive leader (UPL) was initiated by a rapid, repetitive burst of 14 precursor pulses. Upon initiation, the VHF radiation abruptly became continuous with time. Significantly, breakdown during the UPL appeared to extend the discharge in a similar manner to that of the precursor pulses. Key Points: Close VHF interferometer observations reveal the breakdown processes of triggered lightning with submicrosecond and meter‐scale resolution Transient precursor pulses during the ascent of a wire‐trailing rocket are confirmed to originate at the top of the triggering wire Breakdown processes during the upward positive leader of triggered lightning appear to resemble those observed during precursor pulses