Plasma is the fourth state of the matter. State of matter changes from solid to liquid and from liquid to gas when exposed to heat. And gas exposed to heat is ionized and becomes conductive. This ionized and conductive state of matter is called plasma.
In plasma cutting, the pressurized gas is forced through a torch nozzle in which an arc is generated. This process heats the gas up to more than 20000°C.
Thus, the obtained plasma jet allows to cut conductive materials such as steel, aluminium and copper, in high precision.