Plasma generation

A plasma torch 100 having an open end 105 comprises a tapered central cathode rod 2 and a grounded conductive tube 3, the grounded conductive tube has an open end and is arranged around the cathode and spaced therefrom to form a first cylindrical cavity open at one end; in use, an arc discharge between the cathode and grounded conductive tube ionizes a feed gas to produce a central thermal plasma emitted from the open end of the first cavity. In one embodiment the grounded conductive tube also comprises a lip 9 which helps to control the energy distribution of the plasma plume emitted. In one embodiment a further high voltage electrode 6 is placed around the grounded conductive tube and separated from it using a dielectric 5, this is supplied with a second feed gas which exits though a second opening 106 resulting in a non-thermal plasma halo. In one embodiment a voltage pulse is used to initiate arc discharge and the flow rate of the gas can be controlled. The plasma torch is used for cosmetically treating skin.