Seeing the process in action is almost magical, but it works by using the effects the plasma has on the air against itself.

This allows the controller to more efficiently match its drive to the AC frequency demanded by the motor at a particular speed, and is responsible for the “gear change” sound of many electric ...

Electric sparks are used for welding ... The hot air is then guided by ultrasonic waves into regions where the sound intensity is higher and the next sparks then follow these regions of lighter ...