PLASMA
Plasma metal cutting is a form of domesticated lightning. In nature, the sheath of the lightning moves very quickly over a great distance, this natural electric arc ionizes the air which it crosses and more in the immediate sheath of the lightning. The principle of plasma cutting is similar, where the giant electric arc of lightning moving over great distances, sometimes kilometers, is this time fixed, of very small size (a few millimeters) and these are the gases that are rubbed there which move at a speed close to the speed of sound.