Abstract: Torch apparatus (20) for working a material comprises a mixer (28) with a central body (32) placed inside the inner space (30) of the mixer, and a torch tip (22) with a combustion chamber (24) and a nozzle (26). Fuel and oxidizer components are delivered into the mixer, mix with each other into a propellant and interact with the central body which includes a spark plug (60) in one of embodiments. The central body acts to control thermodynamic parameters of the propellant mixture to be set to fire from a spark discharge and burnt under high pressure, forming a supersonic high temperature gaseous jet acting upon the material. Also disclosed is a method in which the apparatus is to be implemented and comprising steps of providing a fuel and an oxidizer, mixing the fuel with the oxidizer, burning the propellant mixture under high pressure and forming a supersonic high temperature nonoverwidened gaseous jet out of products of combustion to act upon the material.