US3663858A - Radio-frequency plasma generator - Google Patents

Radio-frequency plasma generator Download PDF

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US3663858A
US3663858A US87534A US3663858DA US3663858A US 3663858 A US3663858 A US 3663858A US 87534 A US87534 A US 87534A US 3663858D A US3663858D A US 3663858DA US 3663858 A US3663858 A US 3663858A
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plasma
slotted
radiofrequency
assembly
generator
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Giuseppe Lisitano
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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
    • H05H1/00—Generating plasma; Handling plasma
    • H05H1/24—Generating plasma
    • H05H1/46—Generating plasma using applied electromagnetic fields, e.g. high frequency or microwave energy

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  • a plasma generator which utilizes radio frequency power and [5 I I Ila. Cl. ..H01J l] is f the having a S'otted transmission line consisting of a [58] new of Search l 11 hollow tubular body electrically matched to an RF generator, in which the hollow body makes up a delay line in which the [56] References Cmd RF energy is caused to propagate with a time delay in the UNITED STATES PATENTS direction of the axis of said hollow body the radiofrequency power, by enabling heatmg of the plasma independent of the Targ et al ..315/3.5 intensity of a magnetic used for confining the plasma 3,1 1 1,604 1 H1963 Agdur provides a highly dense plasma, 2,842,712 7/1958 Mildoon et al..
  • the subject invention consists of a plasma generator which utilizes radiofrequency power as transferred by means of a transmission line placed internally of a metal tube, in order to obtain a highly dense plasma and to heat it independently from the intensity of the magnetic field used for confining the plasma.
  • the radiofrequency line is electrically coupled to a generator which produces energy in a frequency band which is extended from a few megacycles to the field of centimetric waves.
  • Plasma generators utilizing radiofrequency power are well known in the art. They couple radiofrequency power to the plasma by means of a) transmission lines placed internally of a metal tube; b) radiofrequency inductance coils; c) microwave cavity resonators and d) microwave horn radiators.
  • none of said known radiofrequency plasma generators is able to produce: a) high density fully ionized plasma, and b) collisionless heating of otherwise produced high density plasma.
  • Another object is to provide a plasma generator giving fully ionized plasma for gases of any mass number.
  • a further object is to provide a high density plasma having a particle number density (N, cmof interest for controlled thermonuclear fusion research work.
  • the present invention improves absorption of RF energy by the plasma in such a way that, for a certain RF power level, very high ionization degrees and temperatures for a gas are obtained.
  • the present invention permits to obtain discharges of ionized gases in metal tubes which have been filled with gases having various mass numbers and at very low pressure in the order of between 10 Torr up to the atmospherical pressure.
  • This object can be achieved by virtue of the basic feature of this invention which permits to match high RF power densities per volume unit within tubes having an inside diameter which is much smaller than the wavelength of the matched energy.
  • an RF plasma generator which is formed by a hollow cylindrical body having an RF transmission line arranged so as to provide a delay line, so that the RF energy is propagated in the axial direction with a phase velocity which is much lower than the propagation speed of the wave in vacuo.
  • the hollow body contains a slot of helical configuration, which is wound around the axis of the hollow body and is electrically matched to an RF generator.
  • FIGS. 1, 2 and 3 show constructional examples of the invention, with coaxial matching of the input energy
  • FIGS. 4 and 5 show constructional examples of the invention with waveguide type input.
  • the slotted transmission line as disclosed by the present invention is shown in FIGS. 1 to 5.
  • the transmission line is slotted helically on a tubular cylinder. Radiofrequency power is fed through a matched transition from a coaxial or from a waveguide input connector to one end of the slotted transmission line. The other end of the transmission line may be openor short-circuited.
  • the plasma absorption mechanism of the radiofrequencypower fed to the slotted transmission line structure of this invention is believed to depend upon: a) the polarization of the E-field of the radiofrequency power and b) the strength of the fringing E-field across the slots of the slotted transmission line.
  • said absorption mechanism will be illustrated describing the distinguishing features of the present slotted-line structure compared with other radiofrequency coils or helical conductors windings used in other devices such as, for example, travelling wave tubes.
  • the E-fringing field of the radiofrequency power is mainly directed axially in the same direction of the applied magnetostatic field, like the polarization of an ordinary wave.
  • the plasma can be produced independent of the strength of the confining magnetostatic field, in agreement with the non-dependence of the propagation of an ordinary wave from the magnetostatic field strength.
  • the only possible radiofrequency field is the fringing field across the slotsof the slotted transmission line. Therefore a minimum r.f. field configuration will be established inside the slotted cylindrical structure, in absence of plasma.
  • the minimum r.f. field configuration is still established even for a structure diameter larger than that corresponding to cut-off.
  • N 10 cm the plasma frequency is much larger than the frequency of the applied radiofrequency power.
  • the radiofrequency power being polarized like an ordinary wave, is radiated transversally to the applied magnetic field and is thus cut-off at the plasma-boundary. This establishes again the condition of a minimum r.f.-field configuration in presence of plasma.
  • the electron velocities are randomized by the alternating radiofrequency fields, thus producing an "effective collision frequency much higher than that corresponding to a cold plasma at the same neutral gas pressure.
  • This increased r.f. resistivity, in an otherwise collisionless plasma, is believed to be the main absorption mechanism of the wave launched by this structure.
  • the r.f. power is uniformly distributed all around the surface of the plasma. This very important characteristic of the present invention, avoids the instabilities and the losses of other conventional systems like wave-guide radiators, which inject large amount of r.f. power through a small plasma surface.
  • the radiofrequency power coupled by the structure disclosed in the present invention is absorbed as it travels along the slotted transmission line.
  • a large plasma surface can be enclosed by using more than one of such structures.
  • the present device has been tested for a wide range of neutral gas pressure p magnetic field strength B, radiofrequency power level P, plasma diameter D, plasma frequency w, and exciting frequency m or wavelength
  • B neutral gas pressure
  • P radiofrequency power level
  • D plasma diameter
  • D plasma frequency
  • w plasma frequency
  • the plasma generator shown in FIG. 1 contains an RF generator 10, which, through a coaxial line as represented in a diagrammatical fashion, 12, is matched to a system which has a solid cylindrical portion, 14, and an inner cylinder, 16, with helical slots, 18.
  • the outer cylindrical portion, 14, is connected to the external line of the coaxial cable 12, and the inner cylindrical portion is connected to the internal line of the coaxial cable 12.
  • the assembly as shown in FIG. 1, and especially the cylinder 16 with its grooves 18, makes up a delay line by whose means the RF as supplied by the generator, 10, is propagated in the direction of the axis, 20, with a diminished velocity.
  • a hot plasma having a high density can be obtained with a high effciency of RF energy conversion, even under the influence of extreme variations of the pressure of the neutral gas and in the presence of wide variations of the axial magnetic field B. This is because the delay line has a very satisfactory match in a very wide band for matching the RF generator, 10, to the plasma.
  • the external portion, 14, can be formed by a portion of a vacuum container (not shown in the drawings) to which it is connected by end flanges, 22.
  • the magnetic field can be generated by the coils, 24, which have been very diagrammatically shown in FIG. 1.
  • the inside diameter of the slotted cylinder 16 was about 3 ems. and with and RF generator 10, having an output power of about 70 watts at 2 Gigahertz, it has been possible to generate a plasma having a density of a few 10 cm
  • the degree of ionization has been 30 percent and the electronic temperatures, as measured, were of about to 12 eV.
  • the intensity of the axial magnetic field could be varied between 1.5 kiloGauss and the maximum value available was 4.5 kiloGauss.
  • radiofrequency powers above 150 watts, it has been possible to achieve a full ionization of a neutral gas, e.g. argon, at working pressures of Torr.
  • FIG. 2 shows the external portion, 14a and the internal portion, 16a, of a second embodiment of the invention, which differs from that of FIG. 1 only in the method of matching the coaxial line, 12a, the latter being shown in cross-section.
  • the constructional example of FIG. 3 has, also, a coaxial inlet, 12b, from which start the helical slots 18b, these being symmetrical with respect to a plane containing the center of the axial connector, 12b, and arranged perpendicularly to the axis, 20.
  • FIG. 4 gives an example of construction of the invention, wherein the energy coming from an RF generator is matched to the inner portion, 160, by the waveguide 120, and is terminated at the slot 18c. The inner portion is still shielded by a continuous
  • the constructional example of FIG. 4 is especially suitable for the case where the diameter D of the internal cylinder is greater than the RF wavelength.
  • FIG. 5 shows a constructional example which is essentially akin to that of FIG. 4. The difference consists in that, whereas the slot 18c of FIG. 4 is a continuous helix fed at the center, the slot 18d of FIG. 5 comprises two helical grooves which are symmetrical with respect to the feeding point and thus have opposite directions of winding relative to the axis, 20.
  • the portion 16 should be constructed with a conductive material, at least on its surface, the portion 14 can be made either of a conductive or nonconductive material, and possibly it may even be dispensed with completely.
  • the portions 14 and 16 need not take a cylindrical shape but they can have the shape of conical sector, parabolic sectors prisms, pyramids and others.
  • the slot 18 can be open or can be filled with dielectric material(25 In the latter instance, the portion 16 can become an integral part of the vacuum system for the discharges at low pressure or it can become an integral part of a portion of the discharge duct for residual gases, for example for discharges at high pressures, in the order of the atmospherical pressures.
  • a plasma generator assembly of the type utilizing radiofrequency power for its heating means and wherein a static coaxial magnetic field is used to confine plasma comprising: an outer container for plasma; a radiofrequency generator means for supplying radiofrequency power to the plasma; a transmission member connected to said generator means and disposed in the outer container for conveying radiofrequency energy to the plasma, the transmission member including a slotted substantially tubular hollow conductive body; and means to produce a static magnetic field to confine the plasma therein, the assembly characterized in that the arrangement of the slotted hollow body of the transmission member enables polarization of a fringing radiofrequency field to be directed relative to the confining static axial magnetic field.
  • a plasma generator assembly as claimed in claim 1 in which said tubular hollow conductive body is helically slotted, the-assembly including coaxial connector matching means to match the radiofrequency generator means with the helically slotted conductive body.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • Electromagnetism (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Plasma Technology (AREA)

Abstract

A plasma generator which utilizes radio frequency power and is of the kind having a slotted transmission line consisting of a hollow tubular body electrically matched to an RF generator, in which the hollow body makes up a delay line in which the RF energy is caused to propagate with a time delay in the direction of the axis of said hollow body the radiofrequency power, by enabling heating of the plasma independent of the intensity of a magnetic field used for confining the plasma, provides a highly dense plasma.

Description

Unite States Lisitano atent 1 1 May 16, 1972 [54] RADIO-FREQUENCY PLASMA 3,363,138 l/l968 Gruber et al ..315/39 GENERATOR 3,432,722 3/1969 Naydan et al. 315/39 3,388,287 6/1968 Keenan 315/39 [721 mam, Max'planche'strasse 3 317 784 5/1967 Ferran ..315/39 Garching near Munich, Germany [22] Filed: Nov. 6, 1970 FOREIGN PATENTS OR APPLICATIONS [21] APPL 87,534 1,261,608 2/1968 Germany ..315/3.5
Primary Examinerl-lerman Karl Saalbach Foreign Application Data Assistant Examiner-Saxfield Chatmon, Jr.
Nov. 6, 1969 Germany ..P 19 55 914.9 stem 52 us. (:1 ..315/39, 315/111, 176/3, ABSTRACT 176/7 A plasma generator which utilizes radio frequency power and [5 I I Ila. Cl. ..H01J l] is f the having a S'otted transmission line consisting of a [58] new of Search l 11 hollow tubular body electrically matched to an RF generator, in which the hollow body makes up a delay line in which the [56] References Cmd RF energy is caused to propagate with a time delay in the UNITED STATES PATENTS direction of the axis of said hollow body the radiofrequency power, by enabling heatmg of the plasma independent of the Targ et al ..315/3.5 intensity of a magnetic used for confining the plasma 3,1 1 1,604 1 H1963 Agdur provides a highly dense plasma, 2,842,712 7/1958 Mildoon et al.. 3,378,723 4/1968 Napoli et al. ..315/39 5 Claims, 5 Drawing Figures RADIO FREQUENCY I0 G E N ERATO R v 2 0 l I H l I l W 5 --s zz g 24 1s 24 SQ;
3 Sheets-Sheet 1 RADIO FREQUENCY w. v wm 10 F GENERATOR m, if 24 Pakenfied may 16, 1972 5 Sheets-Sheet :3
RADIO-FREQUENCY PLASMA GENERATOR The subject invention consists of a plasma generator which utilizes radiofrequency power as transferred by means of a transmission line placed internally of a metal tube, in order to obtain a highly dense plasma and to heat it independently from the intensity of the magnetic field used for confining the plasma.
The radiofrequency line is electrically coupled to a generator which produces energy in a frequency band which is extended from a few megacycles to the field of centimetric waves.
Plasma generators utilizing radiofrequency power are well known in the art. They couple radiofrequency power to the plasma by means of a) transmission lines placed internally of a metal tube; b) radiofrequency inductance coils; c) microwave cavity resonators and d) microwave horn radiators.
However, for confining magnetic field strengths higher than those corresponding to ionor to electron cyclotron resonance, none of said known radiofrequency plasma generators is able to produce: a) high density fully ionized plasma, and b) collisionless heating of otherwise produced high density plasma.
It is the principal object of this invention to provide a simple radiofrequency plasma generator operative at any value of the confining magnetic field strength.
Another object is to provide a plasma generator giving fully ionized plasma for gases of any mass number.
A further object is to provide a high density plasma having a particle number density (N, cmof interest for controlled thermonuclear fusion research work.
Further objects of this invention are: a) stabilization of the produced plasma by means of a minimum radiofrequency field configuration; b) easy adaptation of the present radiofrequency plasma source to almost any available device for plasma physics and controlled thermonuclear fusion research work; c) utilization of high levels of radiofrequency power at any available frequency in the frequency range between a few Mc/s and many tens of thousands of Mc/s.
The present invention improves absorption of RF energy by the plasma in such a way that, for a certain RF power level, very high ionization degrees and temperatures for a gas are obtained.
In addition, the present invention permits to obtain discharges of ionized gases in metal tubes which have been filled with gases having various mass numbers and at very low pressure in the order of between 10 Torr up to the atmospherical pressure. This object can be achieved by virtue of the basic feature of this invention which permits to match high RF power densities per volume unit within tubes having an inside diameter which is much smaller than the wavelength of the matched energy.
The above objects are achieved, according to the invention, by an RF plasma generator which is formed by a hollow cylindrical body having an RF transmission line arranged so as to provide a delay line, so that the RF energy is propagated in the axial direction with a phase velocity which is much lower than the propagation speed of the wave in vacuo.
The hollow body contains a slot of helical configuration, which is wound around the axis of the hollow body and is electrically matched to an RF generator.
The invention is disclosed in the following with the aid of a few practical examples, as shown in the accompanying drawings.
FIGS. 1, 2 and 3 show constructional examples of the invention, with coaxial matching of the input energy, whereas FIGS. 4 and 5 show constructional examples of the invention with waveguide type input.
The slotted transmission line as disclosed by the present invention is shown in FIGS. 1 to 5. In the present arrangement the transmission line is slotted helically on a tubular cylinder. Radiofrequency power is fed through a matched transition from a coaxial or from a waveguide input connector to one end of the slotted transmission line. The other end of the transmission line may be openor short-circuited.
The plasma absorption mechanism of the radiofrequencypower fed to the slotted transmission line structure of this invention is believed to depend upon: a) the polarization of the E-field of the radiofrequency power and b) the strength of the fringing E-field across the slots of the slotted transmission line.
In the following, said absorption mechanism will be illustrated describing the distinguishing features of the present slotted-line structure compared with other radiofrequency coils or helical conductors windings used in other devices such as, for example, travelling wave tubes.
Some of said distinguishing characteristics, which are essential properties of the present invention, are:
a. Provision of matched transition from coaxial or waveguide input connectors to the slotted transmission line of the present wave-couplin g devices.
b. Fringing E-Fields of the radiofrequency power travelling along the slotted transmission line have a field strength which is independent of the path of said transmission line.
c. Polarization of the E-Field of the radiofrequency power:
This is very important in any plasma-wave interaction process and can be fixed in a very simple way, in the present invention, by fixing the path of the slotted transmission line. It is thus possible to take account of the particular plasma-wave dispersion relation in order to couple said wave to the plasma. As an example, in the FIGS. 1 to 5 of the present invention, the E-fringing field of the radiofrequency power is mainly directed axially in the same direction of the applied magnetostatic field, like the polarization of an ordinary wave.
It is probably due to this particular characteristic of the present invention, that the plasma can be produced independent of the strength of the confining magnetostatic field, in agreement with the non-dependence of the propagation of an ordinary wave from the magnetostatic field strength.
d. Provision of a minimum radiofrequency field configuration inside the slotted cylinder:
When the diameter of the slotted cylinder has cut-off dimensions for the wavelength of the radiofrequency power, the only possible radiofrequency field is the fringing field across the slotsof the slotted transmission line. Therefore a minimum r.f. field configuration will be established inside the slotted cylindrical structure, in absence of plasma.
In presence of plasma, the minimum r.f. field configuration is still established even for a structure diameter larger than that corresponding to cut-off. In fact, at the operating plasma particle number density, N, 10 cm the plasma frequency is much larger than the frequency of the applied radiofrequency power. The radiofrequency power, being polarized like an ordinary wave, is radiated transversally to the applied magnetic field and is thus cut-off at the plasma-boundary. This establishes again the condition of a minimum r.f.-field configuration in presence of plasma.
e. Stabilization of the produced plasma by said minimum r.f.field configuration.
The absence of this property would cause (like in other known systems of radiofrequency plasma generators) wall losses and instabilities of the produced plasma.
f. Radiofrequency power capabilities of the present devices:
These are such as to allow the coupling of a large amount of radiofrequency power, of the order of many kilowatts per liter of plasma volume. The absorption mechanism of this r.f. power is believed to be due to an increased resistance of the plasma to the alternative fringing fields across the slots.
At large values of said fringing E-fields, the electron velocities are randomized by the alternating radiofrequency fields, thus producing an "effective collision frequency much higher than that corresponding to a cold plasma at the same neutral gas pressure. This increased r.f. resistivity, in an otherwise collisionless plasma, is believed to be the main absorption mechanism of the wave launched by this structure.
g. Distribution of the radiofrequency power:
The r.f. power is uniformly distributed all around the surface of the plasma. This very important characteristic of the present invention, avoids the instabilities and the losses of other conventional systems like wave-guide radiators, which inject large amount of r.f. power through a small plasma surface.
The radiofrequency power coupled by the structure disclosed in the present invention is absorbed as it travels along the slotted transmission line. A large plasma surface can be enclosed by using more than one of such structures.
h. Discharge parameters:
The present device has been tested for a wide range of neutral gas pressure p magnetic field strength B, radiofrequency power level P, plasma diameter D, plasma frequency w, and exciting frequency m or wavelength The following table gives the tested ranges of the discharge, but the limitations are only due to the limitations of available test apparatus and energy, used up to date for these tests.
The plasma generator shown in FIG. 1 contains an RF generator 10, which, through a coaxial line as represented in a diagrammatical fashion, 12, is matched to a system which has a solid cylindrical portion, 14, and an inner cylinder, 16, with helical slots, 18. The outer cylindrical portion, 14, is connected to the external line of the coaxial cable 12, and the inner cylindrical portion is connected to the internal line of the coaxial cable 12. The assembly as shown in FIG. 1, and especially the cylinder 16 with its grooves 18, makes up a delay line by whose means the RF as supplied by the generator, 10, is propagated in the direction of the axis, 20, with a diminished velocity. In the interior of the cylinder, 16, a hot plasma having a high density can be obtained with a high effciency of RF energy conversion, even under the influence of extreme variations of the pressure of the neutral gas and in the presence of wide variations of the axial magnetic field B. This is because the delay line has a very satisfactory match in a very wide band for matching the RF generator, 10, to the plasma.
The external portion, 14, can be formed by a portion of a vacuum container (not shown in the drawings) to which it is connected by end flanges, 22. The magnetic field can be generated by the coils, 24, which have been very diagrammatically shown in FIG. 1. With a system according to FIG. 1, for which the inside diameter of the slotted cylinder 16 was about 3 ems. and with and RF generator 10, having an output power of about 70 watts at 2 Gigahertz, it has been possible to generate a plasma having a density of a few 10 cm The degree of ionization has been 30 percent and the electronic temperatures, as measured, were of about to 12 eV. The intensity of the axial magnetic field could be varied between 1.5 kiloGauss and the maximum value available was 4.5 kiloGauss. With radiofrequency powers above 150 watts, it has been possible to achieve a full ionization of a neutral gas, e.g. argon, at working pressures of Torr.
In the applications for discharges at atmospherical pressures, the influence of the magnetic field as regards the priming of the discharge results in very high frequency of the electron-ion collisions. Apparently, the use of an axial magnetic field, in addition to diminishing the losses towards the walls of the plasma generator, lends itself in an outstanding manner to the formation of magnetic nozzles having a controlled rate of flow.
FIG. 2 shows the external portion, 14a and the internal portion, 16a, of a second embodiment of the invention, which differs from that of FIG. 1 only in the method of matching the coaxial line, 12a, the latter being shown in cross-section.
The constructional example of FIG. 3, has, also, a coaxial inlet, 12b, from which start the helical slots 18b, these being symmetrical with respect to a plane containing the center of the axial connector, 12b, and arranged perpendicularly to the axis, 20.
FIG. 4 gives an example of construction of the invention, wherein the energy coming from an RF generator is matched to the inner portion, 160, by the waveguide 120, and is terminated at the slot 18c. The inner portion is still shielded by a continuous The constructional example of FIG. 4 is especially suitable for the case where the diameter D of the internal cylinder is greater than the RF wavelength.
FIG. 5 shows a constructional example which is essentially akin to that of FIG. 4. The difference consists in that, whereas the slot 18c of FIG. 4 is a continuous helix fed at the center, the slot 18d of FIG. 5 comprises two helical grooves which are symmetrical with respect to the feeding point and thus have opposite directions of winding relative to the axis, 20.
The constructional examples as described above, can, of course, be modified without departing from the scope of the invention. While the portion 16 should be constructed with a conductive material, at least on its surface, the portion 14 can be made either of a conductive or nonconductive material, and possibly it may even be dispensed with completely. The portions 14 and 16 need not take a cylindrical shape but they can have the shape of conical sector, parabolic sectors prisms, pyramids and others. The slot 18 can be open or can be filled with dielectric material(25 In the latter instance, the portion 16 can become an integral part of the vacuum system for the discharges at low pressure or it can become an integral part of a portion of the discharge duct for residual gases, for example for discharges at high pressures, in the order of the atmospherical pressures.
What is claimed is:
1. A plasma generator assembly of the type utilizing radiofrequency power for its heating means and wherein a static coaxial magnetic field is used to confine plasma, comprising: an outer container for plasma; a radiofrequency generator means for supplying radiofrequency power to the plasma; a transmission member connected to said generator means and disposed in the outer container for conveying radiofrequency energy to the plasma, the transmission member including a slotted substantially tubular hollow conductive body; and means to produce a static magnetic field to confine the plasma therein, the assembly characterized in that the arrangement of the slotted hollow body of the transmission member enables polarization of a fringing radiofrequency field to be directed relative to the confining static axial magnetic field.
2. A plasma generator assembly as claimed in claim 1 in which said tubular hollow conductive body is helically slotted, the-assembly including coaxial connector matching means to match the radiofrequency generator means with the helically slotted conductive body.
3. A plasma generator assembly as claimed in claim 1 in which said tubular hollow conductive body is helically slotted, the assembly including waveguide input connector means to match the radiofrequency generator means with the helically slotted conductive body.
4. An assembly as claimed in Claim 1 in which said outer I container is substantially tubular and is coaxial with said slotted substantially tubular hollow body.
5. An assembly as claimed in claim 9 in which at least the slots of the slotted tubular hollow body are filled with an insulating material.

Claims (7)

1. A plasma generator assembly of the type utilizing radiofrequency power for its heating means and wherein a static coaxial magnetic field is used to confine plasma, comprising: an outer container for plasma; a radiofrequency generator means for supplying radiofrequency power to the plasma; a transmission member connected to said generator means and disposed in the outer container for conveying radiofrequency energy to the plasma, the transmission member including a slotted substantially tubular hollow conductive body; and means to produce a static magnetic field to confine the plasma therein, the assembly characterized in that the arrangement of the slotted hollow body of the transmission member enables polarization of a fringing radiofrequency field to be directed relative to the confining static axial magnetic field.
2. A plasma generator assembly as claimed in claim 1 in which said tubular hollow conductive body is helically slotted, the assembly including coaxial connector matching means to match the radiofrequency generator means with the helically slotted conductive body.
2. A plasma generator assembly as claimed in claim 1 in which said tubular hollow conductive body is helically slotted, the assembly including coaxial connector matching means to match the radiofrequency generator means with the helically slotted conductive body.
3. A plasma generator assembly as claimed in claim 1 in which said tubular hollow conductive body is helically slotted, the assembly including waveguide input connector means to match the radiofrequency generator means with the helically slotted conductive body.
3. A plasma generator assembly as claimed in claim 1 in which said tubular hollow conductive body is helically slotted, the assembly including waveguide input connector means to match the radiofrequency generator means with the helically slotted conductive body.
4. An assembly as claimed in Claim 1 in which said outer container is substantially tubular and is coaxial with said slotted substantially tubular hollow body.
5. An assembly as claimed in claim 9 in which at least the slots of the slotted tubular hollow body are filled with an insulating material.
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US3814983A (en) * 1972-02-07 1974-06-04 C Weissfloch Apparatus and method for plasma generation and material treatment with electromagnetic radiation
US3911318A (en) * 1972-03-29 1975-10-07 Fusion Systems Corp Method and apparatus for generating electromagnetic radiation
US4057462A (en) * 1975-02-26 1977-11-08 The United States Of America As Represented By The United States Energy Research And Development Administration Radio frequency sustained ion energy
US4390495A (en) * 1981-01-19 1983-06-28 Energy Profiles, Inc. Control of colliding ion beams
US4584159A (en) * 1979-09-17 1986-04-22 Energy Profiles, Inc. Plasma wave damping system and method
DE3711184A1 (en) * 1987-04-02 1988-10-20 Leybold Ag DEVICE FOR THE APPLICATION OF MICROWAVE ENERGY WITH AN OPEN MICROWAVE LEAD
US4792732A (en) * 1987-06-12 1988-12-20 United States Of America As Represented By The Secretary Of The Air Force Radio frequency plasma generator
DE3915477A1 (en) * 1988-05-11 1989-11-23 Hitachi Ltd MICROWAVE PLASMA MANUFACTURING DEVICE
DE4004560A1 (en) * 1989-02-15 1990-08-16 Hitachi Ltd MICROWAVE-INDUCED PLASMA SOURCES
EP0502269A1 (en) * 1991-03-06 1992-09-09 Hitachi, Ltd. Method of and system for microwave plasma treatments
WO1994006263A1 (en) * 1992-09-01 1994-03-17 The University Of North Carolina At Chapel Hill High pressure magnetically assisted inductively coupled plasma
DE4337119A1 (en) * 1993-10-29 1995-05-24 Univ Dresden Tech VHF plasma source useful for etching and coating processes
US5668442A (en) * 1994-05-13 1997-09-16 Hughes Electronics Plasma-assisted tube with helical slow-wave structure
WO1999021496A1 (en) * 1997-10-24 1999-05-06 Fugo Richard J Device for plasma incision of matter with a specifically tuned radiofrequency electromagnetic field generator
US5958266A (en) * 1997-10-24 1999-09-28 Fugo; Richard J. Method of plasma incision of matter with a specifically tuned radiofrequency electromagnetic field generator
DE19923018C2 (en) * 1999-05-19 2001-09-27 Univ Dresden Tech Device for processing band-shaped workpieces using resonant high-frequency plasmas
AU750001B2 (en) * 1998-07-09 2002-07-04 Richard J. Fugo Device for plasma incision of matter with a specifically tuned radiofrequency electromagnetic field generator
US6518703B1 (en) * 1998-03-16 2003-02-11 Matsushita Electrical Industrial Co., Ltd. Electrodeless discharge energy supply apparatus and electrodeless discharge lamp device using surface wave transmission line
US6787730B2 (en) 1998-07-09 2004-09-07 Damian Coccio Device for plasma incision of matter with a specifically tuned radiofrequency electromagnetic field generator
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CN102612863A (en) * 2009-08-24 2012-07-25 韩国基础科学研究院 Microwave antenna for generating plasma
US9734926B2 (en) 2008-05-02 2017-08-15 Shine Medical Technologies, Inc. Device and method for producing medical isotopes
US10734126B2 (en) 2011-04-28 2020-08-04 SHINE Medical Technologies, LLC Methods of separating medical isotopes from uranium solutions
US10978214B2 (en) 2010-01-28 2021-04-13 SHINE Medical Technologies, LLC Segmented reaction chamber for radioisotope production
US11361873B2 (en) 2012-04-05 2022-06-14 Shine Technologies, Llc Aqueous assembly and control method
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WO1999021496A1 (en) * 1997-10-24 1999-05-06 Fugo Richard J Device for plasma incision of matter with a specifically tuned radiofrequency electromagnetic field generator
US5958266A (en) * 1997-10-24 1999-09-28 Fugo; Richard J. Method of plasma incision of matter with a specifically tuned radiofrequency electromagnetic field generator
US6518703B1 (en) * 1998-03-16 2003-02-11 Matsushita Electrical Industrial Co., Ltd. Electrodeless discharge energy supply apparatus and electrodeless discharge lamp device using surface wave transmission line
US6479785B1 (en) 1998-07-09 2002-11-12 Richard J. Fugo Device for plasma incision of mater with a specifically tuned radiofrequencty electromagnetic field generator
US6787730B2 (en) 1998-07-09 2004-09-07 Damian Coccio Device for plasma incision of matter with a specifically tuned radiofrequency electromagnetic field generator
US6867387B2 (en) 1998-07-09 2005-03-15 Richard J. Fugo Device for plasma incision of matter with a specifically tuned radiofrequency electromagnetic field generator
US20050173383A1 (en) * 1998-07-09 2005-08-11 Damian Coccio Device for plasma incision of matter with a specifically tuned radiofrequency electromagnetic field generator
US7173211B2 (en) 1998-07-09 2007-02-06 Rjf Holdings Ii, Inc. Device for plasma incision of matter with a specifically tuned radiofrequency electromagnetic field generator
AU750001B2 (en) * 1998-07-09 2002-07-04 Richard J. Fugo Device for plasma incision of matter with a specifically tuned radiofrequency electromagnetic field generator
DE19923018C2 (en) * 1999-05-19 2001-09-27 Univ Dresden Tech Device for processing band-shaped workpieces using resonant high-frequency plasmas
US7770456B2 (en) * 2003-06-04 2010-08-10 Adrian Stevenson Electromagnetic piezoelectric acoustic sensor
US20060207330A1 (en) * 2003-06-04 2006-09-21 Stevenson Adrian Electromagnetic piezoelectric acoustic sensor
US8088126B2 (en) 2006-08-17 2012-01-03 Fugo Richard J Method and apparatus for plasma incision of cardiovascular tissue
US20080045941A1 (en) * 2006-08-17 2008-02-21 Fugo Richard J Method and apparatus for plasma incision of cardiovascular tissue
US8137341B2 (en) 2006-08-17 2012-03-20 Richard J Fugo Methods and apparatus for plasma incision of tissue
US9734926B2 (en) 2008-05-02 2017-08-15 Shine Medical Technologies, Inc. Device and method for producing medical isotopes
US11830637B2 (en) 2008-05-02 2023-11-28 Shine Technologies, Llc Device and method for producing medical isotopes
CN102612863B (en) * 2009-08-24 2014-11-19 韩国基础科学研究院 Microwave Antennas That Produce Plasma
CN102612863A (en) * 2009-08-24 2012-07-25 韩国基础科学研究院 Microwave antenna for generating plasma
US10978214B2 (en) 2010-01-28 2021-04-13 SHINE Medical Technologies, LLC Segmented reaction chamber for radioisotope production
US11894157B2 (en) 2010-01-28 2024-02-06 Shine Technologies, Llc Segmented reaction chamber for radioisotope production
US8796934B2 (en) 2010-01-29 2014-08-05 Forschungsverbund Berlin E.V. Miniaturizable plasma source
DE102010001395A1 (en) * 2010-01-29 2011-08-04 Forschungsverbund Berlin e.V., 12489 Miniaturizable plasma source
DE102010001395B4 (en) * 2010-01-29 2013-11-14 Forschungsverbund Berlin E.V. Miniaturizable plasma source
US10734126B2 (en) 2011-04-28 2020-08-04 SHINE Medical Technologies, LLC Methods of separating medical isotopes from uranium solutions
US11361873B2 (en) 2012-04-05 2022-06-14 Shine Technologies, Llc Aqueous assembly and control method
US12444515B2 (en) 2022-04-15 2025-10-14 Shine Technologies, Llc Device and method for producing medical isotopes

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GB1326412A (en) 1973-08-15
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