In typical conditions, an electrical arc forms when the electric field strength exceeds the dielectric strength of the medium (like air). In a vacuum, there is no medium to ionize, which theoretically makes it difficult for an arc to form. However, electricity can still arc in a vacuum under certain conditions, such as when high voltages are involved or when the electrodes are extremely close together.
big_fat_fluffy@leminal.space 16 hours ago
I was thinking neon lights. I mean that’s basically an arc, just spread out. I think I heard that there’s a glow in vacuum too, just not as nice as with neon.
Trigger2_2000@sh.itjust.works 9 hours ago
Well, a quick search turned up this: Vacuum Arc
However, like the above comment, it seems to refer to freeing electrons from the conducts, so, IMHO, you no longer have a vacuum.
If you could somehow maintain a perfect vacuum; I wonder how this concept Virtual particle would come into play (or if it would at all).