Howdy!
Keeping it real, tearing down an old car, parts into a new one.  Dirt and grease under the nails...bliss.
Turns out that most stun-guns are pulsed AC!  There are output caps, but they just help with the 'snap' at the output.

So I will be going with the old classic: multi-stage voltage multiplier, with a step-up transformer as the input stage.

Thoughts on triggering the CalderaTrode: drill small hole in one of the two 'shrouds', solder in a bit of RG-skinny coaxial cable, with the dielectric protruding into the shroud.  The center conductor might be formed into a 'halo' between the upper and lower electrodes.  A small Marx generator would fire a pulse into the coax, ionizing the space between the electrodes.  Bang!

Hey.
Posted the first installment of TEA Laser stuff on Instructables.
Dang, forgot the link...hold on.
http://www.instructables.com/id/TEA-Laser-on-a-PCB/
That's better.
What is there: Photos of WIP TEA Laser, lots of theory, some how-to tips.  Only capacitors and spark-gap CalderaTrodes [they resemble Volcanoes with deep central craters!] are covered, but in good detail..
What is coming next: Power supply [cheap stun-gun and rectifier], Laser channel, charging inductor and making a cabinet for all that High-Joltage stuff.
May look at a triggered arc-gap modification, too.
More later! 

OK, time to dial it back, get my head clear.

Vacuum Permittivity.
Odd as it may seem, vacuum has a definite electrical impedance, 376 ohms.
But like any dielectric in a capacitor, there are instances where the electrical tension in the dielectric exceeds what the dielectric can handle.
A very sharp voltage spike can cause a capacitor to burst, but not by the typical short-circuit/heating route.
With most dielectrics, there is a slight expansion of the solid in the direction of the electrostatic field.
Simply put, the dielectric swells up with more charge, gets skinny as discharged.
Hit the capacitor with a spike, and the dielectric expands so fast it can fly apart!
Ceramic caps sometimes fail this way.
So, here we go again with the speculation: If you 'spiked' vacuum hard enough, would it 'burst' as well?  Or would it briefly expand to absorb the 'spike'?
This is what my design is counting on.

But in all of this, I really do not have any legitimate reason to think this can work.
My training, experience and all the information I can find says "Nope", the energy just isn't there, there is no Aether to push against, physics just doesn't work that way.
So I continue on a plainly hopeless path, but that is not the point.

There are times when you have to challenge what you believe about yourself and everything in your life.
And if setting a goal known to be impossible is foolish, then I shall be joining good company.
I guess this is going to be my "Philosphers Stone".
That magical something that transforms everything, forever.
And yes, I know a metaphor when I see one!

SO why all this weird physics talk?
Experiments need nano-second or shorter pulses, this kind of arc-switch can deliver!
For fun, and to test the switch in a practical way, I am putting together a TEA laser with my spare PCB.
It will be a typical split-plate capacitor + spark-gap arrangement.
I am considering using 4-40 all-thread stock for the discharge electrodes.  All those little 'teeth' should give oodles of brushy discharges.
We will see.