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A lightning mapping array (green squares) records the leader steps of a ~1.7 s long lightning discharge on 30 August 2012 (upper panel), which causes numerous positive (crosses) and negative (triangles) cloud to ground lightning discharges

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posted on 13.08.2013 by Martin Füllekrug, Ferruccio Zanotti, William Rison, Michel Parrot, Alec Bennett, József Bór, Thomas Farges, Ondrej Santolik, Ivana Kolmasova, Enrico Arnone

Figure 1. A lightning mapping array (green squares) records the leader steps of a ~1.7 s long lightning discharge on 30 August 2012 (upper panel), which causes numerous positive (crosses) and negative (triangles) cloud to ground lightning discharges. A particularly intense positive cloud to ground lightning discharge at 03:33:46.680 (+CG1) causes a sprite (inset figure). The consecutive intense positive cloud to ground lightning discharge at 03:33:47.208 (+CG2) occurs ~60 km north-eastward of the sprite and is recorded with a high frequency radio receiver near Rustrel (RST).

Abstract

The acceleration of electrons results in observable electromagnetic waves which can be used for remote sensing. Here, we make use of ~4 Hz–66 MHz radio waves emitted by two consecutive intense positive lightning discharges to investigate their impact on the atmosphere above a thundercloud. It is found that the first positive lightning discharge initiates a sprite where electrons are accelerated during the exponential growth and branching of the sprite streamers. This preconditioned plasma above the thundercloud is subsequently exposed to a second positive lightning discharge associated with a bouncing-wave discharge. This discharge process causes a re-brightening of the existing sprite streamers above the thundercloud and initiates a subsequent relativistic electron beam.

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