Patent ID: 7645999
Filing Date: 2010-01-12
Classification: H01J,H05H

Abstract:
1. An apparatus for producing a plasma for a work surface, the apparatus comprising: an enclosure adapted to contain an ionizable gas; a plurality of plasma excitation devices each of which is arranged to enable microwaves to travel from a first end thereof to a second end and radiate therefrom into the said gas; means for generating a magnetic field in the gas; and a source of microwaves connected to feed microwaves to the first ends of the excitation devices; wherein the said magnetic field has value B, and the microwaves have a frequency f such as to substantially satisfy the relationship: where m and e are the mass and charge respectively of an electron, and wherein, in use, regions exist within the said gas where the direction of the wave propagation vector of the microwaves is non-parallel to the lines of the magnetic field.