Using a really old AC flyback transformer from a small "portable" TV. primary winding is just 14 turns of awg24 hookup wire wrapped around the core, secondary is the HT coil, all other pins I insulated over.
MOSFET is an IRFP450. Spark gap is set to 20mm.
Nothing much happens until the oscillator is on the right frequency, at that point a solid bright purple plasma arc forms on the gap and sits there quite happily.
still needs work; gate switching is not square, gate isn't biased correctly, there's too much shift in the oscillator, etc.
