Devices and methods of using HF waves to energize a column of gas enclosed in an insulating casing
AssigneeAgence Nationale de Valorisation de la Recherche (ANVAR)
InventorsMichel Moisan, Philippe Leprince, Claude Beaudry, Emile Bloyet
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Abstract
A device which generates plasma by energizing a column of gas with a high frequency periodic electric field of a frequency of at least 100MHz. The generating means extends over only a part of the gas column and the power of the energizing field is such that the plasma generated includes and extends beyond said part of the gas column. In one embodiment the gas column is contained in an elongated insulating casing and the generating means comprises a first metallic tube open at both ends and surrounding a part of the casing, a second tube enclosing the first, and a connecting ring between the first and second tubes.
Claims27
An excitation device for energizing a column of gas enclosed in an insulating casing of elongated form, said device comprising, in combination:
- generator means for generating a high frequency periodic electrical field having a frequency of at least 100 megahertz and supply means for supplying a signal of said frequency to the said generator means, said generator means comprising a plasma energizing structure adapted to be disposed on a part of the length of the said elongated casing, and constituting means for applying a said electrical field to the said column of a value such that, in the absence of a magnetic field, a plasma is generated over a certain length comprising the said part of the length of the elongated casing and an additional length which follows on from said part of the length.
An excitation device for energizing a column of gas contained in an insulating casing of elongated form, said device comprising in combination:
- generator means for generating a high frequency electrical field of a frequency of at least 100 megahertz, and supply means for supplying a signal of said frequency to the said generator means, said generator means comprising a plasma energizing structure disposed over a part of the length of the casing of elongated form, and constituting means for applying a said electrical field to the said column of a value sufficient to produce a plasma over a certain length comprising the said part of the length of the elongated casing and an additional length following on from the said part of said length, the said energizing structure comprising means for generating surface waves in the said column, said surface waves having azimuthal symmetry with respect to the longitudinal axis of the casing.
An excitation device for energizing a column of gas contained in an insulating casing of elongated form, said device comprising generator means for generating a high frequency electrical field of a frequency of at least 100 megahertz and supply means for supplying a signal of said frequency to the said generator means, said generator means comprising a metallic structure comprising a first tube, open at both ends and adapted to receive a fraction of the length of the insulating casing, a second tube enclosing the first tube, and a connecting ring between the first ends of the first and second tubes, the second end of the second tube being closed by a transverse wall having an aperture therein for passage of the elongated casing, the second end of the first tube being separated from the said transverse wall by a gap, the said structure further comprising a metal plate disposed opposite the first tube in the space separating the first and second tubes, the said supply means supplying the said signal to the said metallic plate, and the supply means comprising a coaxial cable extending through an opening provided in the second tube.
An excition device for energizing a column of gas contained in an insulating casing of elongated form, said device comprising generator means for generating a high frequency electrical field of a frequency of at least 100 megahertz, characterised in that said generator means comprises means for generating a surface wave in the said column.
Method of using periodic waves of a frequency of at least 100 Megahertz to energize a column of gas contained in an insulating casing of elongated form, wherein surface waves are created in said column by the generation of a high frequency electrical field of said frequency, the generation of the electrical field ensuring ionisation of the plasma.
Dependencies are inferred from the claim text.