R. K. Haaland

High-Speed Imaging of Sprite Streamers

The spatial and temporal developments of sprite streamers in the mesosphere are discussed in the context of the data recorded on August 27, 2009. Streamers initiate at approximately 75 km in altitude and are seen to propagate first downward and subsequently upward. Streamer splitting is observed as the streamers propagate. The streamer tips are approximately three times brighter than the planet Jupiter.

Sprite beads and glows arising from the attachment instability in streamer channels

A.L. was supported by the Spanish Ministry of Economy and Competitiveness (MINECO) under projects ESP2013-48032-C5-5-R and FIS2014-61774-EXP and by the Junta de Andalucia, Proyecto de ExcelenciaFQM-5965. H.C.S.-N, M.G.M., and R.H. have been supported by the U.S. National Science Foundation grants 1104441 and 1201683 to the University of Alaska Fairbanks and to the U.S. Air Force Academy respectively

Sprite halo structures and streamer onset

Imaging of sprites at 16,000 frames per second indicates that streamers may be spawned from spatial structure in the preceding sprite halo. The halo structures descend rapidly with the sprite halo, but slow down and stop to form the stationary glow seen in the vicinity of the streamer onset. The streamers emerge suddenly from the halo structure propagating downwards at ∼107 m/s. The velocities during the rapid descend of the halo are similar to those of the streamers. The luminous halo structures last longer than the main halo, which fades prior to streamer formation.