The crowd stares at two men with lightning bolts firing from their heads and hands, at the Big Day Out, a music festival in Sydney, Australia. This is the ‘Lords of Lightning’.
The secret to the Lords’ power is Tesla Coils. The ones they use are two metres wide, on which they stand while thick blue bolts fly around them. First developed in 1891 by Nicola Tesla, a Tesla Coil is in fact two coils – one sitting inside the other. When an alternating current builds up in the smaller coil it creates a magnetic field that induces a current in the larger one.
In the show, one primary coil is wound around two secondary coils which service the two towers. This ensures both towers vibrate at the same frequency. Voltage in the larger coil can build up into millions of volts once the coils vibrate at precisely the same frequency. “That’s what causes the huge voltage rises that you see in the way of lightning,” says Carlos Van Camp, the creator of Lords of Lightning. To ramp the voltage further, he winds the coils so the towers are pumped with opposing charges. “So, at maximum, one tower reaches two million volts and the other reaches negative two million,” says Van Camp. The massive voltage generated by the Tesla Coil rips surrounding air molecules into charged ions, allowing a current to flow through the air. This is similar to what it is believed happens in nature. While there is some debate, it’s believed that lightning is caused by the sudden release of charge from thunderclouds, which get electrically riled up by collisions between ice particles. Since most of the charge is negative, the ground becomes positive. Once the electric charge becomes large enough to ionise the air, a current will flow as a lightning bolt.