[TCML] Tesla Magnifier with pancake primary and secondary

[Matt Siri <mattisonsiri@xxxxxxxxx>]

A few months ago, I threw togather a rather small Tesla magnifier from parts 
that I had lying about.
Specifications:
supply: 9kV 60mA NST
primary capacitance: several bottle capacitors in parallel for ~7nF
spark gap: static
pimary coil: flat spiral; ID=7in; 0.25in copper tubing; 0.25in turn spacing; 10 
turns max
secondary coil; flat bifilar spiral (windings wired in parallel); ID=2.5in; 135 
turns (each winding) of 23 awg magnet wire
tertiary coil: helix; d=2.375in; h=16.6in; 27 awg magnet wire; the innermost 
turn of the secondary was connected to the bottom to the tertiary
top load: 6in*0.25in steel disc and a 5in aluminium foil ball
The ouput arc length was near 6in.  Although this is far from the Freau arc 
length of about 40in it was impressive considering the massive amounts of corona 
around the bottle capacitors.
This setup led to the construction of my current magnifier:
primary capacitance: 2*12 MMC of 942C20P15K-F CDE capacitors (25nF; 24kV)
secondary coil: flat spiral; ID=4.5in; OD=23.75in; 375ft of 18 awg speaker wire
tertiary coil: helix; d=4.5in; h=20in; 26 awg magnet wire
top load: 4.5in*18in spun aluminum toroid
The pimary coil, the spark gap, and the supply transformer were the same as 
previously employed.
With this setup, I was able to meet the Freau arc length of 40in.  It would seem 
that the advantages of using flat spiral primary and secondary coils are that 
insulating the two is very easy as only a 0.5in sheet of polypropylene is needed 
and that the use of coils lying on parallel planes with coincidental centers 
makes good use of the magnetic field of the primary coil (this suggests using a 
dual secondary system; one above and one below the primary (yet to be tested)).  
However, when a second 9-60 NST is paralleled with the first (and another rack 
of 12 capacitors is added), the Freau effeciency drops to 80%; a third drops it 
to near 65% (4 total racks).  I suspect that this is due to the low power 
handling capability of the static spark gap.  Any suggestions?
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