A plasma cutter in use.
A Plasma cutter is a device capable of cutting metals. In the cutting process, an inert gas is blown at high speed out of a nozzle; at the same time an electrical arc is formed through that gas from the nozzle to the surface being cut, turning some of that gas to plasma. The plasma is sufficiently hot to melt the metal being cut and moves sufficiently fast to blow molten metal away from the cut.
Major Samantha Carter used a plasma cutter on Prometheus to cut through a bulkhead. (SG1: "Prometheus")
Matthew Scott and Everett Young used this devices to cut some ice and bring it back on Destiny from Hoth. (SGU: "Water")