Don Kelly said:
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What you are effectively saying is: "As AC cannot propagate an ion path
there cannot be ionic conduction between electrodes supplied by AC and that
big fat and hot arc on a AC system is a figment of imagination. Flourescent
lights also will not work on AC as they depend on establishment of an
ionized path."
Also remember than positive electrodes can launch arcs too, even
though the massive positive ions in air travel much slower than the
freed electrons do.
The "spark stuff" reaches out through the air at a much higher velocity
than the actual charges travel. A growing spark is more like a wave
moving through dominos, or a forest fire spreading across trees.
One group of ions becomes a conductive substance, which causes the
e-field to distort and concentrate, which ionizes the neighboring dry
air, and so on in a wave. Also, one group of ions emits UV light,
which as before can ionize the adjoinging air in a travelling wave.
I suspect that the physics greatly resembles the growth of thin
metal-crystal "trees" from solution, where the tips of the crystal
filaments grow much faster than the sides of the filaments, leading
to long narrow tree-like shapes.
With AC, the main issue is whether the ion path "cools off" during
the zero crossing. If it did, a new spark would have to leap out
every 120TH of a second, and each spark would take a different
path. Also, previous sparks could not add new length to existing
spark filaments, so the sparks would be much shorter. Clearly the
ionized path does not cool off with hot 60Hz AC sparks, since they
appear as a single glowing filament which slowly crawls around, not
as a collection of shorter sparks which flicker around maniacally.
((((((((((((((((((((((( ( ( (o) ) ) )))))))))))))))))))))))
William J. Beaty Research Engineer
[email protected] UW Chem Dept, Bagley Hall RM74
[email protected] Box 351700, Seattle, WA 98195-1700
ph206-543-6195 http//staff.washington.edu/wbeaty/