Arc Attack
I just switched on the TV and caught a glimpse of Americas Got Talent. The act being auditioned said they combined science and rock music. Quite a show as one of the band stood between two Tesla coils at 500,000V each and got zapped. He was wearing a metal suit so that his body so there would have been no PD across him but I certainly wouldn't have done it, I wouldn't like to be one of the other band members either. On the screen shot you can see that there is a gap after the coil before the lightning starts, why is that?
I have done a bit of web research and have found out that the gap is not always present. Often there is a straight part of the spark before the branching bit. Seems to be something to do with the very high field close to the top of the Tesla coil. I've an excellent explanation of how a Tesla coil works here Tesla's Legacy. Some nice physics.