Red Sprite -- from Eric Weisstein's World of Astronomy

High-altitude flashes excited by lightning which occur between the tops of some thunder clouds and the ionosphere, first reported by Franz et al. (1990). They are barely visible to the unaided eye, but can be observed electronically in the mesosphere at altitudes of 65-75 km. Red Sprites coincide with cloud lightning strokes and persist for only a few milliseconds. The mechanism for generating red sprites is currently not well understood.

Franz, R. C.; Nemzek, R. J.; and Winckler, J. R. "Television Image of a Large Upward Electrical Discharge Above a Thunderstorm System." Science 249, 48, 1990.

Sentman, D. D.; Wescott, E. M.; Osborne, D. L.; Hampton, D. L.; and Heavner, M. J. "Preliminary Results from the Sprite94 Aircraft Campaign, 1, Red Sprites." Geophys. Res. Let. 22, 1205, 1995.

Sentman, D. D. and Wescott, E. M. "Red Sprites and Blue Jets: High-Altitude Optical Emissions Linked to Lightning." EOS, Trans. Amer. Geophys. Union 77, 1-4, 1996.