Re: Capping secondary coil forms

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Paul Nicholson by way of Terry Fritz <twftesla-at-qwest-dot-net>" <paul-at-abelian.demon.co.uk>

Daniel Barrett wrote:

 > but I have never seen an arc that wants to be anywhere near the
 > centerline of the coil- they seem to like to go someplace far
 > away from the coil.

Yes, discharges will follow what they feel to be the steepest
descent through the E field.  This takes them out and away from the
rim of the toroid, at least to begin with, before they curve down
towards ground.

In a sense, we are fooling the discharge a little, because the path
of steepest *average* field gradient lies down the center of the
coil, but the discharge doesn't know that!   The tip of the evolving
discharge is only aware of the field in its immediate vicinity, so
it is fooled into starting its journey out sideways from the toroid,
because this is the direction which appears initially steepest.

The shape of the toroid combines with the relatively modest volts
per turn induced in the topmost part of the secondary to produce a
potential landscape which encourages this behaviour.
--
Paul Nicholson,
Manchester, UK.
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