HR: 09:48h
AN: AE51A-09    [Abstracts]
TI: High Time Resolution Telescopic Imaging of Fine Structure in Sprites
AU: * Marshall, R A
EM: ram80@stanford.edu
AF: Stanford University, 350 Serra Mall, Room 306, Stanford, CA 94305 United States
AU: Inan, U S
EM: inan@nova.stanford.edu
AF: Stanford University, 350 Serra Mall, Room 306, Stanford, CA 94305 United States
AB: Experimental documentation of the dynamics of streamer formation and propagation is crucially important for a complete understanding of sprites and their effects on the mesosphere and the lower ionosphere. In July and August 2004, sprites were observed from Langmuir Laboratory using a 1000+ frames-per-second CCD imager mounted to a Dobsonian telescope. Additionally, photometer data was recorded using an array of six photometers with 40 us resolution, and broadband ELF and VLF data was recorded at multiple locations. We present telescopic video observations of sprites at high frame rates, demonstrating very complex structures in both space and time, including bead and streamer formation and propagation. Comparisons show that beads are seen to often propagate at much slower speeds than streamers, and at other times are static, while streamers often propagate at velocities on the order of one-tenth the speed of light. Streamers that appear and disappear within a single frame (i.e., 1 ms), with lateral sizes often in the range of tens of meters are documented. Streamers rarely persist for more than 1-2 ms, while beads persist up to tens of ms and often propagate at slow speeds. Additionally, images show that streamers are often made up of many bead-like structures. Photometer data and ELF/VLF data are also presented, as evidence for sprite halos and early/fast events associated with sprites.
DE: 3324 Lightning
DE: 3334 Middle atmosphere dynamics (0341, 0342)
DE: 3394 Instruments and techniques
DE: 3304 Atmospheric electricity
SC: Atmospheric and Space Electricity [AE]
MN: 2004 AGU Fall Meeting