At its most basic, plasma cutting is a process that cuts through electrically conductive materials with an accelerated jet of hot plasma. So what is plasma then? You can think of plasma as an electrically conductive superheated ionized gas. Lightning is a common example of plasma. In most plasma cutting systems, just as with lightning, the gas being ionized is air. (Systems may use nitrogen or other gases, but air is the most common gas used so we will limit this discussion to air plasma systems.) In an air plasma cutting system, compressed air is directed through a narrow nozzle, and the power supply adds enough energy to the air stream to create a plasma arc with temperatures near 40,000°F. This arc melts a conductive workpiece and the pressurized air flow blows the molten metal away.