Re: Primary Q's and Spark Gaps (and magic formula)

One thing which Mark didn't mention is that at the time of voltage
maximum ALL of the energy originally stored in the primary has
been transferred to the secondary, and that if you could open the
primary circuit at that point you would have optimum efficiency.
Unfortunately, this works out to pretty quick quenching in the
case of the higher coupling coefficients (0.6, particularly).  A
friend of mine told me the other night that he had build a high-
voltage source for a plasma experiment by using coaxial, equal-
length solenoids adjusted for k=0.6, with peak primary voltage
30 kV and peak secondary voltage 1 megavolt!  This work was
done a number of years ago at TRW and he couldn't remember the
coil diameters, but the length was 2 feet and they were separated
by 1/2" of mylar insulation, which apparently worked OK even at
the peak voltage. (Kinda hard to believe, but Lee is a scientist
and really knows what he is doing!)  Anyhow, they used some sort
of high voltage switch to connect the plasma tube to the secondary
at the peak of the voltage maximum, and the whole thing worked as
designed.  Thought this might be of interest.