I briefly tested a configuration/circuit by GiantKiller and Reiyuki here:

https://overunity.com/3344/lords-of-the-ring-2/60/

RF is driven by the blue wire, completely galvanically isolated from the Extra coil around 4.5mhz

0.22uF 3kv capacitor, 600v GDT and a 1kv diode.

System was driven with 5-10 watts.

Using the circuit configuration above the discharge tube would only ignite once, briefly, during RF powerup.

Moving the GDT to the other leg of the capacitor, it would ignite once at powerup and occasionally once during shutdown.

I made one small change by inserting a neon bulb between the capacitor leads, both to act as a visual standing voltage indicator and to act as an impulse source.

Now when turned on, most times the neon bulb and gas discharge tube both light fully. Based on the brightness of the GDT I estimate the full charge of the capacitor is being discharged several times per second.

Two questions arise from this:

1 – How is the high-value capacitor able to fully discharge when it does not have a closed circuit to ground?

2 – Why does this effect only occur when transients are present?