Pub Date : 2002-12-16DOI: 10.1109/ICIMW.2002.1076147
J. Jin, Shi-Chang Zhang, C. Qiu, Xiaoping Liang
In this paper a gyrotron with tapered guide magnetic field is proposed. The transmission quality of the electron beam in this device is investigated and found to be improved. Simulations show the electronic efficiency of the FZK gyrotron experiment might be increased up to 38.7% by tapering the guide magnetic field.
{"title":"Proposal of a coaxial-cavity gyrotron with tapered guide magnetic field","authors":"J. Jin, Shi-Chang Zhang, C. Qiu, Xiaoping Liang","doi":"10.1109/ICIMW.2002.1076147","DOIUrl":"https://doi.org/10.1109/ICIMW.2002.1076147","url":null,"abstract":"In this paper a gyrotron with tapered guide magnetic field is proposed. The transmission quality of the electron beam in this device is investigated and found to be improved. Simulations show the electronic efficiency of the FZK gyrotron experiment might be increased up to 38.7% by tapering the guide magnetic field.","PeriodicalId":23431,"journal":{"name":"Twenty Seventh International Conference on Infrared and Millimeter Waves","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81102921","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-12-16DOI: 10.1109/ICIMW.2002.1076075
M. Airila
The two-dimensional self-consistent time-dependent theory of beam-wave interaction in gyrotron resonators has been modified to account for eccentricity of the annular hollow electron beam. Numerical analysis yields the effect of beam eccentricity on the previously known limiting values of the azimuthal index of the mode, beyond which stationary single-mode operation becomes impossible.
{"title":"Spatio-temporal chaos in a gyrotron resonator with an off-axis electron beam","authors":"M. Airila","doi":"10.1109/ICIMW.2002.1076075","DOIUrl":"https://doi.org/10.1109/ICIMW.2002.1076075","url":null,"abstract":"The two-dimensional self-consistent time-dependent theory of beam-wave interaction in gyrotron resonators has been modified to account for eccentricity of the annular hollow electron beam. Numerical analysis yields the effect of beam eccentricity on the previously known limiting values of the azimuthal index of the mode, beyond which stationary single-mode operation becomes impossible.","PeriodicalId":23431,"journal":{"name":"Twenty Seventh International Conference on Infrared and Millimeter Waves","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78087330","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-12-16DOI: 10.1109/ICIMW.2002.1076139
S. Hansel, A. Kirste, H. Mueller, M. von Ortenberg, E. Huseynov
We report on magnetotransmission measurements of 10.6 μm radiation through bulk InSb in transient megagauss field pulses. The half period of about 6 μs of the oscillating field is comparable to the characteristic relaxation time in the material. Field reversal between the oscillations demonstrates the strong influence of the "history" of the state population within the relaxation time.
{"title":"Infrared detection of carrier dynamics in indium antimonide in megagauss fields","authors":"S. Hansel, A. Kirste, H. Mueller, M. von Ortenberg, E. Huseynov","doi":"10.1109/ICIMW.2002.1076139","DOIUrl":"https://doi.org/10.1109/ICIMW.2002.1076139","url":null,"abstract":"We report on magnetotransmission measurements of 10.6 μm radiation through bulk InSb in transient megagauss field pulses. The half period of about 6 μs of the oscillating field is comparable to the characteristic relaxation time in the material. Field reversal between the oscillations demonstrates the strong influence of the \"history\" of the state population within the relaxation time.","PeriodicalId":23431,"journal":{"name":"Twenty Seventh International Conference on Infrared and Millimeter Waves","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73361543","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-12-16DOI: 10.1109/ICIMW.2002.1076143
K. Kajiwara, C. Baxi, R. Callis, J. Doane, R. Ellis, M. Friend, M. Green, Y. Gorelov, J. Lohr, C. Moeller, R. Pinsker, D. Ponce, R. Prater
The DIII-D ECH system includes three launcher assemblies each of which can accommodate the RF beams from two gyrotrons. The launchers use four different designs for the mirrors which focus and direct the beams into the tokamak. The designs use molybdenum brazed to graphite, thin Glidcop or variable thickness Glidcop. A fourth design with laminated Glidcop/stainless steel construction has been operated, but no thermal data are available. All the mirrors operate without active cooling. This paper presents preliminary analyses and measurements of the thermal performance of the three designs for which data have been obtained.
{"title":"Thermal performance of the launcher mirrors in the DIII-D ECH system","authors":"K. Kajiwara, C. Baxi, R. Callis, J. Doane, R. Ellis, M. Friend, M. Green, Y. Gorelov, J. Lohr, C. Moeller, R. Pinsker, D. Ponce, R. Prater","doi":"10.1109/ICIMW.2002.1076143","DOIUrl":"https://doi.org/10.1109/ICIMW.2002.1076143","url":null,"abstract":"The DIII-D ECH system includes three launcher assemblies each of which can accommodate the RF beams from two gyrotrons. The launchers use four different designs for the mirrors which focus and direct the beams into the tokamak. The designs use molybdenum brazed to graphite, thin Glidcop or variable thickness Glidcop. A fourth design with laminated Glidcop/stainless steel construction has been operated, but no thermal data are available. All the mirrors operate without active cooling. This paper presents preliminary analyses and measurements of the thermal performance of the three designs for which data have been obtained.","PeriodicalId":23431,"journal":{"name":"Twenty Seventh International Conference on Infrared and Millimeter Waves","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83233744","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-12-16DOI: 10.1109/ICIMW.2002.1076084
K. Maeda, K. Fujii, N. Sokabe
We report the self-pulsing dynamics of a CH/sub 3/OH 119 /spl mu/m ring laser pumped with the CO/sub 2/ 9 /spl mu/m P(36) line. Regular pulsation and period bifurcation were observed under uni-directional operation. When the ring cavity was tuned so as to emit bi-directional output, modulated self-pulsing was observed on both the forward and backward emission. The observed dynamics is analyzed by a model of an inhomogeneously broadened three-level system interacting with a pump as well as with counter-propagating far infrared fields.
{"title":"Self-pulsing dynamics of an optically-pumped far infrared ring laser","authors":"K. Maeda, K. Fujii, N. Sokabe","doi":"10.1109/ICIMW.2002.1076084","DOIUrl":"https://doi.org/10.1109/ICIMW.2002.1076084","url":null,"abstract":"We report the self-pulsing dynamics of a CH/sub 3/OH 119 /spl mu/m ring laser pumped with the CO/sub 2/ 9 /spl mu/m P(36) line. Regular pulsation and period bifurcation were observed under uni-directional operation. When the ring cavity was tuned so as to emit bi-directional output, modulated self-pulsing was observed on both the forward and backward emission. The observed dynamics is analyzed by a model of an inhomogeneously broadened three-level system interacting with a pump as well as with counter-propagating far infrared fields.","PeriodicalId":23431,"journal":{"name":"Twenty Seventh International Conference on Infrared and Millimeter Waves","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73564853","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-12-16DOI: 10.1109/ICIMW.2002.1076185
G. Gestrin, B. Yefimov
The electron motion in undulator magnetic fields formed by parallel straight magnets, with alternating polarity, is studied in this work. In a mathematical model the magnets are simulated as dipoles. It is shown that the dipole field is chaotic, with multiple precision, and that it induces a frequent alteration of electron motion direction and also the appearance of braking radiation. The well-known Ginsburg formulas were used (V.L. Ginzburg, Theoretical Physics and Astrophysics, Moscow, Publishing House Nauka, p. 530, 1975).
{"title":"The Motz undulator","authors":"G. Gestrin, B. Yefimov","doi":"10.1109/ICIMW.2002.1076185","DOIUrl":"https://doi.org/10.1109/ICIMW.2002.1076185","url":null,"abstract":"The electron motion in undulator magnetic fields formed by parallel straight magnets, with alternating polarity, is studied in this work. In a mathematical model the magnets are simulated as dipoles. It is shown that the dipole field is chaotic, with multiple precision, and that it induces a frequent alteration of electron motion direction and also the appearance of braking radiation. The well-known Ginsburg formulas were used (V.L. Ginzburg, Theoretical Physics and Astrophysics, Moscow, Publishing House Nauka, p. 530, 1975).","PeriodicalId":23431,"journal":{"name":"Twenty Seventh International Conference on Infrared and Millimeter Waves","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78341204","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-12-16DOI: 10.1109/ICIMW.2002.1076081
W. Kasparek, H. Kumrić, G. Muller, B. Plaum, A. Girard, D. Hitz, G. Melin
The use of available superconducting (SC) magnet technology for ion plasma sources allows the application of electron cyclotron resonance heating (ECRH) at frequencies up to 37 GHz. In that range gyrotrons are the efficient sources. The overmoded transmission lines (needed for the high power) between gyrotron and ion source can be designed with methods also used in ECRH experiments for fusion plasma heating. This paper reports on design of several components such as mode converters, bends, DC breaks and couplers.
{"title":"Development of transmission lines at frequencies of 28-37 GHz for application with ECR ion sources","authors":"W. Kasparek, H. Kumrić, G. Muller, B. Plaum, A. Girard, D. Hitz, G. Melin","doi":"10.1109/ICIMW.2002.1076081","DOIUrl":"https://doi.org/10.1109/ICIMW.2002.1076081","url":null,"abstract":"The use of available superconducting (SC) magnet technology for ion plasma sources allows the application of electron cyclotron resonance heating (ECRH) at frequencies up to 37 GHz. In that range gyrotrons are the efficient sources. The overmoded transmission lines (needed for the high power) between gyrotron and ion source can be designed with methods also used in ECRH experiments for fusion plasma heating. This paper reports on design of several components such as mode converters, bends, DC breaks and couplers.","PeriodicalId":23431,"journal":{"name":"Twenty Seventh International Conference on Infrared and Millimeter Waves","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74440922","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-12-16DOI: 10.1109/ICIMW.2002.1076106
L. Shenggang, Y.Y. Wei, Yan Yang, R. J. Barker
A new approach to the theoretical study of the electron beam-wave interaction in arbitrary RF structures is presented in this paper. In any such interaction system, there are two coordinate systems: the lab system; the rest coordinate system for the plasma, if it exists; and the moving coordinate system for the electron beam. Both the electron beam and the plasma are considered special media with different characteristics. The permittivity tensor and the permeability tensor can be found in the moving coordinate system for the beam while that for the plasma can be found in the lab coordinate system. Then, making use of the transformation of electromagnetic fields in Minkovski space and the Lorentz transformation of the 4D wave vectors, all the physics quantities in the moving coordinate system can be transferred into the lab coordinate system. Then the Maxwell's equations with the transferred constitutive tensors should be used to derive the desired dispersion equation. This new approach is a very efficient and accurate method for the study of electron beam-wave interactions.
{"title":"A new approach for the theory on electron beam-wave interactions","authors":"L. Shenggang, Y.Y. Wei, Yan Yang, R. J. Barker","doi":"10.1109/ICIMW.2002.1076106","DOIUrl":"https://doi.org/10.1109/ICIMW.2002.1076106","url":null,"abstract":"A new approach to the theoretical study of the electron beam-wave interaction in arbitrary RF structures is presented in this paper. In any such interaction system, there are two coordinate systems: the lab system; the rest coordinate system for the plasma, if it exists; and the moving coordinate system for the electron beam. Both the electron beam and the plasma are considered special media with different characteristics. The permittivity tensor and the permeability tensor can be found in the moving coordinate system for the beam while that for the plasma can be found in the lab coordinate system. Then, making use of the transformation of electromagnetic fields in Minkovski space and the Lorentz transformation of the 4D wave vectors, all the physics quantities in the moving coordinate system can be transferred into the lab coordinate system. Then the Maxwell's equations with the transferred constitutive tensors should be used to derive the desired dispersion equation. This new approach is a very efficient and accurate method for the study of electron beam-wave interactions.","PeriodicalId":23431,"journal":{"name":"Twenty Seventh International Conference on Infrared and Millimeter Waves","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77341571","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-12-16DOI: 10.1109/ICIMW.2002.1076058
M. Yeddulla, G. Nusinovich, A. Vlasov, T. Antonsen, K. Felch, S. Cauffman
Long-pulse, megawatt-class gyrotrons operate in very high-order modes. In order to excite only the desired mode in the presence of competing modes in such a gyrotron, the design should take into account the start-up scenario. In this paper the start-up scenario in the 140 GHz, 1 MW gyrotron developed at CPI is described. Simulations were done with the use of self-consistent non-stationary code MAGY.
{"title":"Start-up scenario in a 140 GHz gyrotron","authors":"M. Yeddulla, G. Nusinovich, A. Vlasov, T. Antonsen, K. Felch, S. Cauffman","doi":"10.1109/ICIMW.2002.1076058","DOIUrl":"https://doi.org/10.1109/ICIMW.2002.1076058","url":null,"abstract":"Long-pulse, megawatt-class gyrotrons operate in very high-order modes. In order to excite only the desired mode in the presence of competing modes in such a gyrotron, the design should take into account the start-up scenario. In this paper the start-up scenario in the 140 GHz, 1 MW gyrotron developed at CPI is described. Simulations were done with the use of self-consistent non-stationary code MAGY.","PeriodicalId":23431,"journal":{"name":"Twenty Seventh International Conference on Infrared and Millimeter Waves","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85231886","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-12-16DOI: 10.1109/ICIMW.2002.1076118
Haiyong Xu, G. S. Schoenthal, J. Hesler, R. Weikle, T. Crowe
The development of planar varactor tunerless sideband generators (SBGs) is described in this paper. Integration of the diode with the embedding circuit enhances mechanical robustness and makes the circuits easy to handle compared with a whisker-contacted diode structure. Preliminary measurements at 200 GHz yielded conversion efficiencies of 7-10 dB over more than 20 GHz tuning range. Simulations indicate that THz-scaled SBGs pumped with FIR-lasers (>100 mW) power will yield mWs of tunable THz power.
{"title":"High power tunable millimeter wave sources using fixed-tuned planar varactor sideband generators","authors":"Haiyong Xu, G. S. Schoenthal, J. Hesler, R. Weikle, T. Crowe","doi":"10.1109/ICIMW.2002.1076118","DOIUrl":"https://doi.org/10.1109/ICIMW.2002.1076118","url":null,"abstract":"The development of planar varactor tunerless sideband generators (SBGs) is described in this paper. Integration of the diode with the embedding circuit enhances mechanical robustness and makes the circuits easy to handle compared with a whisker-contacted diode structure. Preliminary measurements at 200 GHz yielded conversion efficiencies of 7-10 dB over more than 20 GHz tuning range. Simulations indicate that THz-scaled SBGs pumped with FIR-lasers (>100 mW) power will yield mWs of tunable THz power.","PeriodicalId":23431,"journal":{"name":"Twenty Seventh International Conference on Infrared and Millimeter Waves","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86875216","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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