Question:
How can red sprite or blue jet "lightning" which is
released from the top of the cloud be explained? Where is the
electrical energy expelled from these phenomena going?
Replies:
Jeremy,
A lot of research and cloud modeling has taken place over the last 5 years
to explain sprites and elves (blue jets). The energy that leads to these
phenomena
clearly comes about as a result of cloud-to-ground (CG) lightning discharges,
although a sprite or jet occurs only once for every 100 or so CGs. Much
like ground lightning strokes, the shape, horizontal and vertical extent,
and energy of sprites and elves can vary greatly, probably as a result of
the strength of charge separation in the cloud. The shapes of sprites
are partially determined by whether the CG has positive or negative
polarity. The energy is expelled directly above the storm and can reach
tens of miles above the Earth. Sprites have been found to be electrically
similar to streamer discharges (the weak electrical flows from a cloud and the
ground before a CG strike).
David Cook
Lightning researcher
Argonne National Laboratory
The physics of lightning is quite complex. The clearest treatment of the
physics of lightning I've seen can be found in Vol. II of Richard Feynman's
LECTURES ON PHYSICS which you should be able to find in the library.
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