Q for Paul Nicholson and other resonator physics experts

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Original poster: Steve Conner <steve@xxxxxxxxxxxx>

Hi all,

I have been playing around with a DRSSTC and have some puzzling observations.

1) When set to operate on the lower pole, the secondary flashes over to the 
primary even at very low power.

2) When set to the upper pole it won't flash over at all. UNLESS it strikes 
ground at high power in which case it flashes over violently with a bright 
white arc to the primary.

I know I am using too high coupling and could fix things by lowering it, 
but I wanted to get to the bottom of what's going on. The RF ground is as 
good as I can make it (counterpoise etc) so I don't think it is poor 
grounding causing transients. And the PLL driver is stable and not putting 
out any silly frequencies. The primary coil voltage is only 5kV peak, not 
enough to explain the difference.

OK that's the background, now the question! I have seen "Mode profiles" on 
Paul Nicholson's site. I noticed that he shows a dual resonator system that 
has two 1/4 wave modes each with a slightly different voltage profile. And 
as far as I understand, these two "modes" are identical to what I and other 
DRSSTC experimenters call the "poles". So my question is this-

Could the upper pole have an E-field profile that is "Skinny" at the bottom 
where the primary is and then bulges out towards the top? And the lower 
pole have the opposite shape, fat at the bottom and tapering towards the 
top? Paul's graphs only showed a tiny difference but he was modelling a 
coil with low k. I have k=0.3 on my setup so the difference might be radical.

If this were true it would also explain why it flashes over when arcing to 
ground. The upper pole's voltage profile gets its shape due to the induced 
voltage (M*dip/dt) being 180' out of phase with and partially cancelling 
the free resonance voltage (Ls*dis/dt). It cancels best at the bottom 
because that's where the primary, and hence most of the induction is.

Now if the secondary arced to ground it would be heavily damped and the 
free resonance voltage would disappear, so the cancellation would not 
happen any more and the net voltage across the bottom part of the secondary 
might actually increase?

Does any of this sound right?


Steve Conner