In article ,
The Natural Philosopher writes:
Mike Tomlinson wrote:
In article , The Natural Philosopher
writes

Its not an arc.

Oh really? What is it then?


Plasma discharge

An arc is a current flow in a plasma.

Plasma includes an arc, but it just means atoms have become
disassociated so the charged particles are not locked together
and are free to conduct electricity (in this case, electrons
disassociated from their nucleus). Thus a plasma includes other
situations such as high temp/pressure states where there's no arc
(no current flow). Under some definitions, a solid metal is also
a plasma (because the electons are mobile), but it's not normally
useful to include this.

You wouldn't call an old style TV tube an arc either.

and it isn't - it's an electron beam in an otherwise vacuum.

Or a neon tube (which is essentially what a fluorescent is..

Or a radio valve. All have currents passing through gases Or a partial
vacuum..

Nor will you strike an arc more than a few mm with 240VAC.

It takes about 25KV to strike an arc across a spark plug....

Arc has jargon meaning in lighting, physics, and electronics,
and they're all subtly different, and not well defined.

However, in the context of lighting, an arc is a current passing
through a plasma, and includes fluorescent tubes, HID lamps, neons,
carbon arc lamps, etc.

--
Andrew Gabriel
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