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Detailed Reference Information |
Gerken, E.A. and Inan, U.S. (2002). A survey of streamer and diffuse glow dynamics observed in sprites using telescopic imagery. Journal of Geophysical Research 107: doi: 10.1029/2002JA009248. issn: 0148-0227. |
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While the fine structure in sprites can assume a wide variety of shapes, sizes, and timescales, certain patterns such as upward branching, downward branching, beading, columns, bidirectional streamers, and propagating large-scale diffuse glow regions are repeatedly observed. Example cases of these streamer and diffuse glow dynamics observed in sprites are presented using video data obtained by a telescopic imaging system in July--August 1998 and are compared to predictions of current sprite and streamer theories. The previously unreported propagating diffuse glows move slowly (~104 m/s) and are broader than that predicted for a streamer formation at the same altitude. Sudden brightening of slowly developing negative streamers may be indicative of a return stroke process in which the streamers connect with charge in a lowered ionosphere. Meteoric dust particles in the upper atmosphere may be responsible for the fine beading that exists in many negative streamers and may cause plasma enhancements that initiate double-headed streamers. Beads at the base of columns can glow for over 100 ms while slowly drifting upward (~104 m/s). Columns may initiate from downward branching positive streamers. Faint positive streamers are observed at the base of and/or preceding large bright sprite events. Some sprites may initiate as double-headed streamers formed in localized regions of enhanced electron density. A transition between the streamer formation region and the diffuse glow region is observed at ~80-km altitude. No fine structure is observed in telescopic images of the diffuse glow region also referred to as the sprite halo <Barrington-Leigh and Inan, 2001>. |
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Abstract |
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Keywords
Ionosphere, Ionospheric irregularities, Meteorology and Atmospheric Dynamics, Lightning, Ionosphere, Ionosphere/atmosphere interactions |
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Publisher
American Geophysical Union 2000 Florida Avenue N.W. Washington, D.C. 20009-1277 USA 1-202-462-6900 1-202-328-0566 service@agu.org |
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