Re: [TCML] Re: Position of baffle inside secondary

[Paul Nicholson <tcml88@xxxxxxxxxxx>]

Dex Dexter wrote:

> I was surprised to learn of the existance of the optimum
> coupling with respect to the best performance of SG coils.

Theoretical considerations must be guided by the hand
of practical experience here.   It is regularly but not
always observed that onset of racing arcs limits coupling.
Nobody knows why this is.   High k leads to fewer cycles for the
energy transfer, but all the voltages and currents remain about
the same - at least at the fundamental operating frequency.
So why should racing arcs and flashover appear?  Unknown.

> But even if the conditions are such that secondary itself
> is free from undesired discharges ,beyond certain coupling
> point spark lenghts might start to diminish!

Here too, the reasons are unknown.  Coupling affects the
envelope of the RF, and therefore perhaps the ability to build
long streamers.  Little is known about how the coil/topload
combination interacts with its irregular and complicated spark
loading.  So many variables involved, instrumentation is a
challenge, and realistic modelling of the TC/spark interaction
is, well, a pipe dream.

Nobody has yet had the audacity to square up to these problems.

I think that practical experience has led to 'typical' TC
design rules that (re)produce coils which are probably close
to optimum.  I don't think there's any yet-to-be-discovered
recipe that will go way beyond the present state of the art.
Our inability to explain why a certain range of k is desirable,
and so on, is merely an embarrassment to theorists, rather than
a hidden key to great new performance.  Perhaps that thought
is why nobody is pushing these boundaries of our understanding.

(Not to mention the hideous cost of a digital scope with enough
RAM to capture the entire bang waveform at high time resolution!)
--
Paul Nicholson
--
_______________________________________________
Tesla mailing list
Tesla@xxxxxxxxxxxxxx
http://www.pupman.com/mailman/listinfo/tesla