Do you understand ignition is due to dielectric breakdown in Xenon under 1/2 A pressure?
Breakdown threshold increases with rise time, thus >>18kV is needed with 450Vdc and with no pulse 2kVdc is needed
With no DC, much higher Impulse voltage is needed and for 300Vdc somewhere in between.
When ignition, or detonation or dielectric breakdown occurs, like ESD or lightning or any gas tube discharge lamp, reaction time due to negative resistance of ionization, is fast.
ESD for example in a small gap like Partial Discharge in oil in a power transformer only has 10 ps rise time due to small local inductance inside the dielectric.
Thus trigger only ignites and follow-on voltage drops quickly to low impedance capacitor voltage and high current sustained for RC time constant except R is non-linear and is inverse to current so R*A^.5 is constant. ( Faraday discovered this )
So sequence is simple, trigger then follow-on voltage with current.
holding current depends device when it goes below this, the impedance rises instantly , as detonations stops and residual voltage is left on Cap.
The same is true for SCR's which has negative resistance and holding current. with low voltage trigger.