Sprite beads originating from inhomogeneities in the mesospheric electron density

Abstract

Small, persistent luminous spots observed in sprites may be originated by underlying inhomogeneities in the density of free electrons. Using a streamer density model, we show that the collision of a streamer with a localized enhancement of ionization leaves a region of reduced conductivity and enhanced field in the streamer channel. We discuss the light emissions from this region and predict its spectrum. These emissions are identified with "sprite beads" and we propose that they may serve to investigate the spatial distribution of free electrons in the upper atmosphere above a thunderstorm. Copyright © 2011 by the American Geophysical Union.