Most compact high voltage source for making long arcs

Question

Out of curiosity, I have a question about high voltage electricity sources. Hypothetically, the requirements are that the source must be no larger than a water bottle (although smaller is better), and that the source is capable of producing an arc at least 1 meter in length (longer is better). The source doesn't have to be able to output continuously and can be pulsed, although the time between pulses should be no longer than 1/2 of a second. I am aware that tesla coils can produce large sparks in small packages, but I do not know if they would be the best option for the hypothetical situation or if they are even capable of meeting these criteria. Perhaps some sort of capacitor array?

Answer 1

You will need 3 × 10^6 V (three megavolts) to achieve a spark in dry air. That's rather a lot.

However, people have built hand-held Tesla coils that achieve roughly what you're asking for: http://www.rmcybernetics.com/projects/DIY_Devices/plasma-gun-2.htm (and they'll even sell you the parts!) As "Guess Who" points out, it's quite a challenge to avoid insulation breakdown inside your device.

This exploits the tendency of charged sharp points to spray ions into the air, reducing the breakdown voltage considerably.

Answer 2

The (hypothetical) requirements for your device are insanely unrealistic. Air breakdown voltage (voltage required to create a spark of a certain length through air) varies based on a ton of things, but in general, the "standard" value (all variables aside) is about 3x10^6 V/m. That's a huge voltage. I remember hearing from a professor once (and this could be outdated or completely wrong information) that on even the best of days, it takes about 100,000 volts to create an inch of spark. To create a spark that's a meter long, with circuitry that's the size of a water bottle is, dare I say it, impossible.