Re: RF envelope waveshape: the answer to short SSTC sparklength?

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

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

In a message dated 1/13/02 9:51:11 AM Eastern Standard Time, tesla-at-pupman-dot-com
writes:


>
> The waveshape of the RF envelope is incredibly important to coil
> output voltage and current. Why?


Justin,
I agree the RF envelope is very important.  I think it's related to the
way the ions are caused to be arranged around the toroid.  If the
output is CW, a bushy plasma forms, because all the ions build
up and concentrate around the toroid our breakout point.  If the
sparks are intermittent, it gives the excess ions which are not
in the streamer, time to disperse.  Thus, the next pulse is more
likely to follow fewer paths and cause better spark growth.  I see
the waveshape as related to controlling how the ions distribute,
and control the leader-growth.

I notice on tube coils, the worst envelope is a decrementing
waveform, it makes the sparks short, raspy and bushy.  A rising
envelope is much better.  It seems that a rising envelope lets the
spark grow from a initial straight short spike, which then grows
in the same direction as the power increases.  Some of these
effects may be very related to tuning effects too, which are
constantly changing as the coil is loaded/unloaded during
pulsed operation.

Cheers,
John