I need some help from experienced coilers. I have witnessed a dim glow from a compact fluorescent bulb inductively coupled to a "receiver" coil when that coil is connected to ground on one end.

My problem is that the secondary "transmitter" coil is arcing over between its own turns quite drastically at 2 spots about 1/5th and 2/3 of its height. Arc-over does not happen when the top load discharges to a ground wire brought close enough to the steel ball top load. Those discharges are brilliantly white and about 100dB loud. If a ground wire is removed further and further from the top-load until the point where no more visible discharge is happening the secondary starts to arc over.

Setup: 3 foot high, 58 cm diameter secondary with appr. 500 m of insulated AWG 14 wire. 20 cm top-load, 1 foot above coil. Primary power is supplied by 2 microwave transformers in series appr. 4400 Volts, rotary spark gap, 80nF tank capacity.

I am only getting about 30 cm long discharges to a ground wire from the steel ball on top so my secondary voltage can't be too great, what is the issue here?

Thanks
Gerhard