HR: 11:20h
AN: AE42A-05 INVITED    [Abstracts]
TI: Sprite Processes Quantified With Submillisecond Video and Electromagnetic Measurements
AU: * Cummer, S A
EM: cummer@ee.duke.edu
AF: Duke University, PO Box 90291, Durham, NC 27708, United States
AB: During a summer 2005 observation campaign, high speed imaging and ground-based electric and magnetic field measurements were combined in an effort to probe the details of the connection between the low altitude lightning processes and high altitude transient luminous events (TLEs). The low frequency sensitivity of the magnetic field sensors enabled measurement of the continuing lightning current that is involved in many complex sprites but that can be difficult to detect by other means, while the high speed video gave precise timing of TLE onset and features relative to the driving lightning processes below. We report results from an ongoing detailed and quantitative analysis of this combined data set, including the following elements: measurements of streamer dynamics, including velocity profiles and observations of nearly constant deceleration of many downward streamers below about 60 km altitude; observations of the lightning processes involved in the initiation of delayed sprites; the quantitative agreement between conventional breakdown theory and measurements of sprite initiation time and altitude combined with the integrated lightning charge moment change; and measurements of high altitude sprite current and an analysis of possible sources of this mesospheric charge transfer.
DE: 3304 Atmospheric electricity
DE: 3324 Lightning
DE: 3334 Middle atmosphere dynamics (0341, 0342)
SC: Atmospheric and Space Electricity [AE]
MN: 2007 Fall Meeting