Abstract: A device for producing microwave plasma with a high plasma density. The device comprises at least one microwave supply that is surrounded by an outer dielectric tube. The microwave supply is surrounded by, in addition to the outer dielectric tube, at least one inner dielectric tube that extends inside the outer dielectric tube. The outer dielectric tube and the at least one inner dielectric tube form at least one area that is suitable for receiving and conducting a fluid. The device can be cooled by a fluid. A process gas can be fed into the plasma region by the outer dielectric tube.

Abstract: A device for locally producing microwave plasma. The device comprises at least one microwave feed that is surrounded by at least one dielectric tube. At least one of the dielectric tubes, such as an outer dielectric tube, is partially surrounded by a metal jacket. A locally delimited plasma is produced by the device by shielding microwaves.