I agree with this posting. A lightning bolt ionizes a column of air. The
energy stored in that ionized air (as compared to its previous state)
theoretically could be given in joules per cubic meter. However, the
diameter of that column is at best difficult to estimate and does not
have a discreet boundary anyway. Thus it makes sense to state the value
of the stored energy in terms of column length, which is a few orders of
magnitude greater than the column's diameter.
The question remaining in my mind is whether the energy considered is
only that of the ionized air or if it includes the energy of the
transported electrical current passing through that column. We were not
made privy to the article so we cannot tell.
Jim Frysinger
On 2016-08-09 09:08, jmsteele9...@sbcglobal.net wrote:
Respectfully disagree, and I earlier posited that it was energy per unit
length of the bolt. In electrical and magnetic fields, line sources are
frequently assumed as an approximation. Of course, real sources would
tend to have a diameter, but for distances large compared to diameter,
but small compared to length, a line source is a convenient
approximation. You can then go on to determine the energy stored in
space around the line source or power radiated from it and it will have
dimensions of J/m, W/m or for long florescent tubes, lumens per meter.
Now I will admit that lightning bolts aren't very straight and the
usefulness of this measure in this situation isn't very apparent to me.
However, I can think of cases where it is very useful, long, straight
wires, lighting, etc.
--
James R. Frysinger
632 Stoney Point Mountain Road
Doyle TN 38559-3030
(C) 931.212.0267
(H) 931.657.3107
(F) 931.657.3108
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