This one’s for Delia Derbyshire.
That is Arc Attack performing the theme music to Dr Who which Derbyshire worked on: she didn’t write the tune (Ron Grainger did) but she created the electronic sounds that made it so memorable.
What these guys do is use a pair of Tesla coils, invented by the remarkable Nikola Tesla:
It is essentially a high-frequency air-core transformer. It takes the output from a 120vAC to several kilovolt transformer & driver circuit and steps it up to an extremely high voltage. Voltages can get to be well above 1,000,000 volts and are discharged in the form of electrical arcs. Tesla himself got arcs up to 100,000,000 volts, but I don't think that has been duplicated by anybody else. Tesla coils are unique in the fact that they create extremely powerful electrical fields. Large coils have been known to wirelessly light up florescent lights up to 50 feet away, and because of the fact that it is an electric field that goes directly into the light and doesn't use the electrodes, even burned-out florescent lights will glow.
Arc Attack also do an even more spectacular instrumental version of Black Sabbath’s “Iron Man”, in which the guitarist uses an iron guitar in a Faraday cage. You can see it here. It is amazing. This was on the semi-finals of this year’s America’s Got Talent, for which one of the judges was Sharon Osbourne, who said, “The next time you do ‘Iron Man’, I know somebody who can sing it for you.”
More spectacular Tesla coil photos at this Australian site. For example: