Re: More on spark delay

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

Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>" <Kchdlh-at-aol-dot-com>

Peter (& all)-

Comment re your P.S. below...

In a message dated 04/23/2002 5:18:22 PM Pacific Daylight Time,
tesla-at-pupman-dot-com writes:


>
> Subj:Re: More on spark delay 
> Date:04/23/2002 5:18:22 PM Pacific Daylight Time
> From:<mailto:tesla-at-pupman-dot-com>tesla-at-pupman-dot-com
> To:<mailto:tesla-at-pupman-dot-com>tesla-at-pupman-dot-com
> Sent from the Internet 



[snipped]

>
> (ps,
> A comment about the notion of inertial confinement, the air heats up as
> a consequence of the current flowing through it, this lowers its
> resistance and a higher current brighter spark forms. But from basic 
> physics the _expansion_ of the air/plasma actually _cools_ it. I'm not
> saying that inertial confinement cannot be having an effect, I just don't
> myself see how it would. The lowering of resistance of the air is not a
> function of it expanding, at least as I see it. Perhaps high pressure plasma
> does have a high resistance compared to 1-Atm, I don't really know, but I
> always presumed that plasma already had disassociated electrons and thus
> low resistance regardless of pressure...?
> )




Hmmm...  But I wonder if it is not so that the air around the spark is actually
being compressed and not expanded?  The spark is heating the air along its
immediate path, forcing that air outward against the cooler air that exists all
around the heated air.  The inertia of the cooler air will cause the air
between the spark's path and that cooler air to be compressed.  And all of that
air will have to be pushed out of the way, requiring energy to do that, for the
spark to progress.  Be reminded of the loud >bang!<.  That bang comes from
compressed air, after all.  So, am I purveying goofy science, or?...

Ken Herrick