Патент USA US3031413код для вставки
April 24, 1962 R. R. WARNECKE ETAL 3,031,399 HIGH-FREQUENCY UTILIZATION APPARATUS FOR IONIZED GAS Filed Nov. 12. 1959 INVENTORS Rob er!‘ R. WA R/VECKE e/ ?deae malhe V/N ENT BY .4 ATTORNEYS ‘*nited tates atet i 3,031,399 , FOR IONIZED GAS \ ' Robert R. Warnecke and Germaine Vincent, Paris, France, assignors to Compagnie Generals dc Tele ' l i " (Cl. 204-1932) within a con?ned resonant space by means of which the high~frequency electromagnetic ?eld is tuned to the reso nant frequency thereof so as to effectively con?ne and compress the gas. These and other objects, features and advantages of‘the present invention will become more obvious from the following description when taken in connection with the Filed Nov. ‘12, 1959, Ser. No. 852,268 Claims priority, application France Dec. 8, 1958 10 Claims. Patented Apr. 24, 1962 2 HIGH-FREQUENCY UTILIZATION APPARATUS graphic sans Fil, Paris, France ‘ " 3,31,399 accompanying drawing which shows in the single ?gure ’ thereof, for purposes of illustration only, an automatic 10 frequency control system for use with a prior art appa The present invention relates to an apparatus in which ratus for con?ning and compressing a heavily ionized a strongly ionized gaseous medium is con?ned within an gaseous medium. . evacuated vessel by’ means of a high-frequency electro Referring now to the drawing which illustrates in the magnetic ?eld, and more particularly to an apparatus pro schematic diagram of the single FIGURE thereof the vided with one or several‘ cavity resonators con?ning and 15 present invention in connection with a known prior art compressing therein, by means of a high-frequency elec arrangement, reference numeral 1 designates therein a tromagnetic ?eld, a strongly ionized gaseous medium so quartz tube in communication, ‘by means of conduit 2, with as to effectively insulate the same from the walls of the the source 3 for the admission or input of the gas and with vessel to enable su?icient heating of the resulting so-called the pump 4. The ends of the tube 1 are open or suitably plasma with a goal to produce a thermo-nuclear fusion 20 perforated, and penetrate, in a vacuum-tight manner, into reaction.v the inside of cavity resonators 5 and ‘6. A high fre Devices are known in the prior art of nuclear physics quency electromagnetic ?eld is excited within the cavity which include a casing or vessel ?lled with a strongly resonators 5 andf6 by means of the energy produced, by ionized gas, that is, in the status of plasma, which is sub the high frequency generator or oscillator 7 and propa jected to a con?ning action within a portion of this casing 25 gated or transmitted through the conduits or Wave guides or vessel ‘for the purpose of compressing the same within 8 and 9 to the resonator cavities 5 and 6. said portion, and, on the other hand, to thermally insulate The frequency of the generator 7 is usually tuned to or isolate the plasma from the walls of the casing or vessel coincide with the resonant frequencies of the cavities 5 with a view to obtain an ei?cient heating of the plasma and 6. The vessel or casing of the installation which is 30 evacuated is de?ned or delimited by means of windows 10 that may eventually lead to nuclear fusion reactions. However, in the prior art devices utilizing a cavity and 11 through, which the'electromagnetic energy may resonator, di?iculties arise in the operation thereof due ?ow. The assembly is also placed in an axial magnetic to the fact that the resonant frequency of the cavity ?eld produced by the windings or coils 12. The elements changes in the course of the formation of the plasma. As described so far hereinabove by reference to the single the resonant frequency of the cavity undergoes changes, 35 ?gure of the drawing are all of known conventional the ?xed frequency output from the oscillator producing construction and may be realized in any manner known the high-frequency electromagnetic ?eld at a predeter in the prior art. mined frequency no longer bears the desired relationship to the resonant frequency of the cavity, i.e., the frequency The operation of the prior art devices ‘described so far hereinabove is as ‘follows: of the electromagnetic ?eld set up within the cavity reso 40 After having admitted gaseous medium from the source nator no longer corresponds to the resonant frequency 3 into the tube 1 and after having established a very low of the cavity. It follows therefrom that as soon as the pressure by means of the vacuum pump 4, a high-fre high-frequency oscillator is not tuned to the resonant fre quency electromagnetic ?eld is established within the quency of the cavity, the e?‘iciency of the system decreases cavities 5 and 6. This electromagnetic ?eld which is rela by the reduction in the electromagnetic ?eld within the 45 tively intense since the generator 7 is tuned to the reso resonator cavity which, in turn, decreases the compres nant frequency of the cavities 5 and 6, thereby ionizes sion effect on the plasma. the gaseous medium present within the cavities 5 and 6 The present invention is concerned with a system im whereupon the tube 1 ?lls‘ itself with plasma. The proving the prior art devices and eliminating therefrom plasma is thereby con?ned to the vicinity of the axis of the shortcomings and disadvantages thereof mentioned the tube 1 by the magnetic ?eld produced ‘by the coils 12. hereinabove. At the same time, as may be readily demonstrated theor Accordingly, it is an object of the present invention to etically as well as experimentally, the high-frequency ?eld provide an apparatus for compressing a strongly ionized exercises on the plasma a pressure which displaces the gaseous medium within a cavity resonator by means of an plasma from the cavities 5 and 6 into the tube 1. The electromagnetic high-frequency ?eld which eliminates 55 density of the plasma thereby increases within the tube -'1 and obviates the inconveniences and shortcomings of the and decreases correspondingly within the cavities 5 and 6-, prior art devices and which also assures a relatively high the corresponding'values thereof being relate-d to each e?'iciency throughout the entire course of the operation other. It also follows therefrom that the plasma is com of the device and of the formation of the plasma. pressed within the space thermally insulated from the 60 Another object of the present invention is the provision walls of the tube 1, a space in which the plasma is con of an apparatus for con?ning and compressing a strongly ?ned by the magnetic ?eld. ionized gas within an enclosure formed by a cavity reso However, experience also has clearly established that nator by means of an electromagnetic ?eld which includes the operation of such a prior art device is disturbed by means to assure a continuous tracking of the output fre the variation in the resonant frequency of the cavities 5 quency of the electromagnetic-?eld-producing oscillator 65 and 6 which is caused as the plasma is formed. Con with the resonant frequency of the cavity Within which sequently, the formation of the plasma entrains a detun the gas is con?ned and‘compressed. ing of the, cavities 5 and 6 with respect to the normally Still another object of the present invention resides in ?xed output frequency of the generator 7 resulting in a the provision of automatic frequency control means for lowering or reduction of the high-frequency ?eld, a fact use with the source producing a high-frequency electro 70 which may be very important.’ Furthermore, the com magnetic ?eld in an apparatus of the type described pression' of’ the plasma is very inet?cient as a result hereinabove in which a strongly ionized gas is compressed thereof; 3,031,399 3 ll ing of the electromagnetic wave energy into an electric signal usable as automatic frequency control are not lim ited to the particular details described herein but may be replaced by other means known to a person skilled in the The present invention aims at an improvement over such a prior art device by completely eliminating the dis advantages encountered in connection therewith. According to the present invention, the variations in the art. density of the plasma within tube 1 which, as pointed out Thus, it is quite obvious that the present invention is not hereinabove, are related to the variations in the density of limited to the details shown and described herein but may the plasma within the cavities 5 and 6, a density upon be varied and modi?ed considerably within the spirit and which also depends the resonant frequency of the cavities scope of the present invention, and we, therefore, do not 5 and 6, are utilized to derive therefrom a signal applied to the high-frequency oscillation generator 7 which itself 10 wish to be limited to the details illustrated herein but in tend to cover all such changes and modi?cations as are en is of the type adapted to be electronically tuned in such a compassed by the scope of the appended claims. manner as to automatically re-tune the generator 7 to the We claim: resonant frequency of the cavities 5 and 6 by taking into 1. In an apparatus for compressing plasma, an evacu consideration the presence of the plasma so that the de tuning effect is effectively annulled and the high-frequency 15 ated vessel, means for admitting low pressure gas into said vessel, at least one cavity resonator having its interior in ?eld within cavities 5 and 6, as well as the density of the communication with said vessel, means for supplying high plasma within tube 1, are retained at the maximum pos frequency energy to said resonator to excite the same Sible value thereof. substantially at its natural resonance frequency thereby The present invention also aims at a practical realiza~ ionizing said gas to form plasma and pushing a part of 20 tion with simple means to translate the variations in the said plasma away from said resonator into said vessel, density of the plasma into an electrical signal adapted to means for con?ning said plasma within the interior region perform this control function. of said vessel, and means responsive to the plasma density The present invention will be better understood by ref in said vessel for automatically retuning said high-fre erence again to the single FIGURE of the drawing, and, 25 quency supplying means to the natural resonance fre , in particular, to the elements thereof designated by refer quency of said resonator with plasma contained therein. ence numerals 13 to 19 which embody the present inven 2. A combination as claimed in claim 1, wherein said tion as applied to the prior art device. high-frequency supplying means is a backward wave oscil As mentioned hereinabove, the generator or oscillator 7 lator. is assumed to be of the type adapted to be electronically tuned. Any suitable oscillator may be used for that pur pose, though the present invention proposes in particular the use of a backward wave oscillator, known under the 3. A combination as claimed in claim 1, wherein said returning means includes a beam source of microwave energy, means for directing said microwave energy beam through said plasma within said vessel, means for col lecting said microwave energy after traversing said to deliver an essentially constant power output over a rela 35 plasma, whereby at least one of the variables consisting tively large tuning band. A second generator 13 of any of amplitude and phase of said microwave energy ex suitable type and having a ?xed frequency is also provided hibits a magnitude depending on said plasma density, in accordance with the present invention, the output of means for detecting at least one of said variables consist which is transmitted through a wave guide 14 to a trans ing of amplitude and phase to thereby obtain an elec mitter horn 15 which, in turn, transmits a Well-de?ned 40 trical signal responsive to said plasma density, and means beam of high frequency energy across the plasma within for applying said signal to said cavity resonator high the tube 1. A receiving horn 16 is disposed on the other frequency supplying means to retune the same to a side of the tube 1 which receives the electromagnetic wave frequency corresponding to a plasma density maximum. trade name of ‘*Carcinotron,” which offers the advantage energy after having been subjected to an attenuation and 4. A combination as claimed in claim 1, wherein said de-phasing in the course of its passage across the plasma 45 high-frequency supplying means is a backward wave os within tube 1, this attenuation and dephasing being vari cillator, and wherein said returning means includes a beam able as a function of the density of the plasma. After de source of microwave energy, means for directing said tection of the received energy within a detector 17 which microwave energy beam through said plasma within said may be a simple recti?er or a phase-detector or discrim inator circuit of any known type, as the case may be, a signal is obtained at the output thereof which varies with the density of the plasma. This output signal passes through a circuit 18 having a suitable transfer function or characteristic in order to adapt the law of the variations of the detected signal varying as a function of the density of the plasma within tube 1 to the law of frequency variation as a function of the control voltage of generator 7, and is thereupon applied by means of connection 19 to the input circuit of the control electrode of the generator or oscilla tor 7 in such a sense that the latter is re-tuned to the res onant frequency of the cavities 5 and 6 under the condi tions of the presence within the tube 1 of plasma having vessel, means for collecting said energy after traversing said plasma, whereby at least one of the variables thereof consisting of amplitude and phase of said microwave en ergy has a magnitude depending on said plasma density, means for detecting at least one of said variables consist ing of amplitude and phase in said energy to thereby ob tain an electrical signal responsive to said plasma density, and means for applying said signal to said backward wave oscillator to electronically retune it to a frequency corre sponding to a plasma density maximum. 5. In an apparatus for compressing an ionized gaseous 60 medium, comprising an evacuated vessel including cavity resonator means, means for establishing a predetermined pressure within said vessel and for regulatnig the presence maximum obtainable density when this tuning is realized. of said gaseous medium Within said vessel, means for sup The present invention results in a considerable improve~ plying to said cavity resonator means high-frequency elec ment in the performance of the prior art device of the type 65 tromagnetic energy at the resonant frequency of said cavity described herein. resonator means to thereby enable the production of However, it is understood that the present invention is plasma from said ionized gaseous medium within said ves not limited to the details shown and described herein but sel, and means operatively connected with said high-fre is susceptible of many changes and modi?cations within quency energy supplying means for automatically adjust the scope and spirit of the present invention. As men 70 ing the output frequency thereof in dependence on the tioned hereinabove, any suitable known circuits or devices density of the plasma within said vessel to provide con may be used to achieve the desired result in connection tinuous correspondence between said resonant frequency with elements 13 to 19. Additionally, the described means translating the variations in the density of the plasma as evidenced by the attenuation and/or de-phas and said output frequency. ' 6. In an apparatus for compressing a strongly ionized 3,031,399 5 6 gaseous medium, comprising an evacuated casing includ ing cavity resonator means, means for regulating the pres pressure and presence of said gas within said casing, means sure and presence of said gaseous medium within said cas ing, means for supplying to said cavity resonator means high-frequency electromagnetic wave energy at the reso quency electromagnetic energy "at the resonant frequency thereof to thereby ionize said gas therewithin and enable nant frequency of said cavity resonator means to thereby ionize said gaseous medium and enable the ‘formation of a plasma within a predetermined portion of said casing, and means operatively connected with said high-frequency for supplying to said cavity resonator means high~fre production of plasma therefrom, means for con?ning said plasma Within said space means, and means operatively connected with said high-frequency energy supplying means for automatically adjusting the output frequency thereof in dependence on the density of the plasma within energy supplying means for automatically adjusting the 10 said portion to provide correspondence between said output frequency thereof in dependence on the density of resonant frequency and said output frequency. the plasma to provide tracking between changes in said 10. A method for continuously obtaining maximum resonant frequency and the output frequency of said high plasma conditions in an evacuated casing having a cavity frequency energy supplying means. ' ' resonator which is supplied with high-frequency electro 7. In an apparatus according to claim 6,‘ wherein said 15 magnetic energy from a high-frequency energy generating last-mentioned means includes means for directing electro device the output frequency of which essentially coincides with the resonant frequency of the cavity resonator, com prising the steps of transmitting a signal of high-frequency wave energy as a function of the density of said plasma, energy through the plasma to detect changes in the density means for receiving the electromagnetic energy after pas 20 thereof re?ecting changes in the resonant frequency of the sage through said plasma portion and for detecting the cavity resonator, and, adjusting the output ‘frequency of changes in said characteristics to thereby produce a con~ the high-frequency generating device as indicated by the trol signal, and means for applying said control signal changes in said signal to retune the generating device to to said high-frequency energy supplying means to thereby the frequency of said cavity resonator. magnetic wave energy through a portion of said plasma to thereby vary the characteristics of the electromagnetic retune the same to the resonant frequency of said cavity resonator means. 8. In an apparatus according to claim 5, wherein said high-frequency energy supplying means includes a back Ward wave oscillator adapted to be electronically tuned over a wide band. 9. In an apparatus for compressing strongly ionized gas, comprising an evacuated casing including cavity reso nator means and space means for the formation of a plasma from said ionized gas, means for regulating the References Cited in the ?le of this patent Australian J. of Physics, vol. 10, No. 1, March 1957, pp. 221-225 (an article by Knox), 204-1545. 30 Proceedings of the Second United Nations International Conference on the Peaceful Uses of Atomic Energy. Held in Geneva, September 1-13, 1958. Vol 32, United Nations, Geneva, 1958. An article by Vendeneove et al., pp. 239-244.