The Fly's Eye:
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|1996 RESULTS||1997 FIELD WORK||1998 FIELD WORK||PUBLICATIONS|
"Elves" are transient luminous events in the lower ionosphere produced by nitrogen fluorescence due to electromagnetic pulses (EMPs) from intense return strokes of lightning discharges.
You can see the predicted [Glukhov and Inan, 1996] intensity of this discharge in a simulation, below. The geometry of the viewing position is indicated in the figure below: The perspective is from 250 km away from the causative lightning discharge, and looks up with a vield of view 66 degrees wide and 36 degrees high. The center of the image in the video corresponds to an altitude of 125 km directly over the lightning, and the video shows the discharge evolve over about a millisecond. Click on the icons to expand or play them.
|elf250.mpg [0.377 MB]|
Alternatively, you can view these snapshots of what an elf would look like from the ground from two different distances:
The last snapshots are integrated over the 33 ms of a video field, so these represent the expected video signature of elves.
Glukhov, V. S., and U. S. Inan, Particle simulation of the time-dependent interaction with the ionosphere of rapidly varying lightning EMP, Geophys. Res. Lett., 23, 16, 1996.
Fukunishi, H. Y., Y Takahashi, M. Kubota, K. Sakanoi, U. S. Inan and W.A. Lyons, Elves: Lightning-induced transient luminous events in the lower ionosphere, Geophys. Res. Lett., 23, 2157, 1996.
Inan, U.S., W.A. Sampson and Y. N. Taranenko, Space-time structure of optical flashes and ionization changes produced by lightning-EMP, Geophys. Res. Lett.,23 ,133 , 1996.
Inan, U. S., C. Barrington-Leigh, S. Hansen, V. S. Glukhov, and T. F. Bell, Rapid Lateral Expansion of Optical Iuminosity in Lightning-Induced Ionospheric Flashes Referred to as 'Elves', Geophys. Res. Lett., 24, 583, 1997.
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