Comparison of photometric measurements and charge moment estimations in two sprite-producing storms

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Abstract

[1] In one relatively small storm on July 2, 2000, 276 sprites were observed between 04:00–07:00 UT. These sprites were largely confined to 70–85 km altitude, were relatively faint and diffuse, and were typically associated with very high peak currents and short time duration. A second storm, on July 4, 2000, had a much larger spatial extent and 27 sprites were observed between 04:00–07:00 UT in a wide range of shapes and time scales spanning 40–90 km altitude. These sprites were produced by 20–120 kA CG's, had complex optical signatures, and were frequently associated with observed ELF radiation. We hypothesize that relatively small storms mainly produce sprites in the form of diffuse glow whereas larger storms with higher cloud tops can initiate streamer discharges leading to more spectacular sprites.

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