Agence Nationale De Valorisation De La Recherche (anvar)

Centre National De La Recherche Scientifique

Jean Marec

Emile Bloyet

Philippe LePrince

Serge Saada

Jacques Migne

A waveguide (130) is coupled to a tubular member (2) by a gap (139) suitable for generating an intense surface wave in a gaseous mixture contained in the tubular member (2). Short circuits (110 and 120) delimit the plasma, thereby generating very high intensity standing microwaves, which increase the energy density of the plasma. An ion laser effect can then be observed, in particular in a mixture of argon and helium, together with optional krypton.

Apparatus for exciting a plasma in a column of gas by means of

In an improved plasma torch, a metal tube delivers a plasma-generating gas to an end discharge outlet. The delivery tube is excited by microwave energy by means of a waveguide of rectangular cross-section. The tube traverses the waveguide through openings of larger diameter than the delivery tube. Metal sleeves are advantageously provided around the tube on each side of the waveguide. Two gases can be delivered to the plasma within concentric tubes. The plasma-formation zone can be moved further away from the waveguide by providing lateral impedance-matching devices along the sleeve.

Plasma torches

A plasma generator comprises a metallic tube of small diameter inside which can circulate a gas such as argon at a small flow rate, which is discharged at the front end of the tube. The tube is coupled with an energizing structure which can comprise a frequency generator supplying electromagnetic microwave via a coaxial connection, a coupling structure allowing the transfer of the energy of the generator to the front portion of the metallic tube. In the absence of a gas current in the tube, the front portion radiates the energy transmitted to it in the manner of an antenna. When a gas is discharged at the end of the tube, said energy allows maintaining a plasma in front of the latter. This plasma generator device is usable in many applications, such as a blowtorch a light source or torch usable in spectrography, a plasma motor or an ion source.

Plasma generator

A plasma generator comprises a metallic tube of small diameter inside which can circulate a gas such as argon at a small flow rate, which is discharged at the front end of the tube. The tube is coupled with an energizing structure which can comprise a frequency generator supplying electromagnetic microwaves, via a coaxial connection, a coupling structure allowing the transfer of the energy of the generator to the front portion of the metallic tube. In the absence of a gas current in the tube, the front portion radiates the energy transmitted to it in the manner of an antenna. When a gas is discharged at the end of the tube, said energy allows maintaining a plasma in front of the latter. This plasma generator device is usable in many applications, such as a blowtorch a light source or torch usable in spectrography, a plasma motor or an ion source.

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Limours, France

Jean Marec