Duo-plasmaline, a surface wave sustained linearly extended discharge

A plasma device - the Duo Plasmaline - is described where the plasma is pro duced by microwaves outside a tube in a low pressure chamber. The waves pro pagate as surface waves partially inside the tube and partially in the plas ma. They are launched from both ends of the tube and produce an axially ext ended, homogeneous plasma. The properties of the waves are investigated by the numerical solution of the wave equation. Experimental results for the r adial and axial profiles of the electron density and the wave field are giv en.