...any ideas to make a large amount of charge appear somewhere would certainly help boost the induction effect that is proposed in this thread
Here's another idea for transferring a charge to the center of a disc, based on one of my own "what if" experiments:
I placed three loops of string through and around a 10" cymbal from a drum set, to provide a non conductive support. (This was a cheap cymbal, not an expensive Zildjian, with all of the inductive, pulse forming ridges.). Then I positioned this about an inch above the 5" top ball of a Van deGraaff generator.
With the Van deGraaff running, I observed a bunch of weak sparks jumping from the top of the ball to the bottom of the sculptured disc, or to the air below the central boss. After a couple of minutes, there was a heavy spark between the two electrodes. This was followed immediately by yellow sparks shooting out from the edge of the cymbal, about every half inch. (Interestingly, every pair of sparks curved together, joining into single sparks moving on out.)
What happened right here was the charge on the ball repelled similar charges out of the metal to the top surface of the disc, as an opposite charge was pulled to the bottom surface of the cymbal's central bump, relative to the VdG's polarity. When the charges built up enough, the heavy spark discharged the equal but opposite charges on the ball and the bottom surface of the boss. This left only the charge on the central region of the top of the cymbal. As a result of this being the only remaining charge, with nothing counter balancing it, the cymbal started functioning as a low value polar capacitor. Since this capacitance was then much lower than that of the previously charged two electrodes, the voltage on the top went way up, exceeding the potential the polar mass could hold, and that static charge flowed from the center outwards, to and beyond the edge, all around. (A solid dilectric would block the spark between the two surfaces.)
So, if you have the equipment, repeat this experiment, with the pick coil above the cymbal, and see if it will register the static electric charge flowing outwards.
Everytime the yellow sparks shot out from the edge, the cymbal jumped violently in some direction, depending on how it was slightly off center. These sparks were longitudinal, so there was an opposite force against the emitting electrode.
The static charge flinged straight out but not back. A ground ring could be placed outwards from the edge, to prevent charge movement past the coil.
Hopes this helps.