The situation when an electron beam is transported through a system of diaphragms or a channel with transverse dimensions close to those of the beam is typical for electron-beam vacuum microwave devices. Inner surfaces of the channel or diaphragms are subjected to bombardment with particles of the beam halo. In high-power devices, this bombardment may cause non-linear phenomena having a substantial effect on transportation of the main part of the beam. We present data on processes similar to those found in developing electron-beam microwave devices with high electron beam parameters. We demonstrate the possibility of a critical influence of complicated phenomena, including generation of secondary particles and plasmas and non-linear collective oscillations, on the transport of a high-power electron beam. The investigations are performed for a broad range of conditions (beam current, energy deposition density on the electrodes surrounding the beam, etc.) and show a universality of the observed phenomena.
{"title":"Experimental studies of dense electron beam transport through diaphragms","authors":"A. Arkhipov, G. Sominski","doi":"10.1109/UHF.1999.787927","DOIUrl":"https://doi.org/10.1109/UHF.1999.787927","url":null,"abstract":"The situation when an electron beam is transported through a system of diaphragms or a channel with transverse dimensions close to those of the beam is typical for electron-beam vacuum microwave devices. Inner surfaces of the channel or diaphragms are subjected to bombardment with particles of the beam halo. In high-power devices, this bombardment may cause non-linear phenomena having a substantial effect on transportation of the main part of the beam. We present data on processes similar to those found in developing electron-beam microwave devices with high electron beam parameters. We demonstrate the possibility of a critical influence of complicated phenomena, including generation of secondary particles and plasmas and non-linear collective oscillations, on the transport of a high-power electron beam. The investigations are performed for a broad range of conditions (beam current, energy deposition density on the electrodes surrounding the beam, etc.) and show a universality of the observed phenomena.","PeriodicalId":348319,"journal":{"name":"Proceedings International University Conference 'Electronics and Radiophysics of Ultra-High Frequencies' (Cat. No.99EX356)","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116014770","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}
Luo Jirun, Zhang Shichang, Ding Yaogen, Song Wenmiao
The solution of the electromagnetic field is given for the TE mode in infinite fan-shaped waveguides. The basic principle of a rotating mode filter with a fan-shaped waveguide is presented. The design method for the filter is discussed by a practical example. The good experiment results for the filter are achieved for TE/sub 03/ mode operation.
{"title":"Design of a rotating mode filter","authors":"Luo Jirun, Zhang Shichang, Ding Yaogen, Song Wenmiao","doi":"10.1109/UHF.1999.787969","DOIUrl":"https://doi.org/10.1109/UHF.1999.787969","url":null,"abstract":"The solution of the electromagnetic field is given for the TE mode in infinite fan-shaped waveguides. The basic principle of a rotating mode filter with a fan-shaped waveguide is presented. The design method for the filter is discussed by a practical example. The good experiment results for the filter are achieved for TE/sub 03/ mode operation.","PeriodicalId":348319,"journal":{"name":"Proceedings International University Conference 'Electronics and Radiophysics of Ultra-High Frequencies' (Cat. No.99EX356)","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114590457","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}
G. Dammertz, O. Dumbrajs, K. Koppenburg, B. Piosczyk, M. Thumm
In this work we discuss how to tune the frequency of a high-power gyrotron. The importance of this problem increases in the case of using gyrotrons in large-size fusion machines. The point is that the magnetic field in large stellarators and tokamaks considerably changes over the distance from the plasma center to its boarder. This means that the resonance condition between the plasma electrons and the gyrotron signal is fulfilled only in a relatively small layer of the plasma. To reach other plasma layers one must either use mechanically steerable mirrors to direct the RF wave to the desired position and to employ the Doppler shift effect, or change the frequency of the source and, hence, the position of the resonance layer in the plasma. It is quite obvious that the second possibility is more attractive, because it reduces the number of mechanically movable parts close to the plasma in a fusion machine and increases reliability of operation of the entire system.
{"title":"Frequency-step-tunable high-power gyrotron for plasma physics applications","authors":"G. Dammertz, O. Dumbrajs, K. Koppenburg, B. Piosczyk, M. Thumm","doi":"10.1109/UHF.1999.787891","DOIUrl":"https://doi.org/10.1109/UHF.1999.787891","url":null,"abstract":"In this work we discuss how to tune the frequency of a high-power gyrotron. The importance of this problem increases in the case of using gyrotrons in large-size fusion machines. The point is that the magnetic field in large stellarators and tokamaks considerably changes over the distance from the plasma center to its boarder. This means that the resonance condition between the plasma electrons and the gyrotron signal is fulfilled only in a relatively small layer of the plasma. To reach other plasma layers one must either use mechanically steerable mirrors to direct the RF wave to the desired position and to employ the Doppler shift effect, or change the frequency of the source and, hence, the position of the resonance layer in the plasma. It is quite obvious that the second possibility is more attractive, because it reduces the number of mechanically movable parts close to the plasma in a fusion machine and increases reliability of operation of the entire system.","PeriodicalId":348319,"journal":{"name":"Proceedings International University Conference 'Electronics and Radiophysics of Ultra-High Frequencies' (Cat. No.99EX356)","volume":"71 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115355461","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}
The triode with virtual cathode (VC) generates gigawatt pulses in a wide frequency band. Basically, existing theoretical investigations of this system were carried by method of numerical simulation and not did explain many experimental facts. The analytical description is more successful for description of generation mechanism. It allows one to find the main dependencies of frequency spectrum and generation efficiency on parameters of the VC triode and resonant system. It makes it possible to build high-efficiency devices.
{"title":"Influence of geometry on electromagnetic oscillation generation in the virtual cathode triode","authors":"V. P. Grigoryev, T. Koval","doi":"10.1109/UHF.1999.787915","DOIUrl":"https://doi.org/10.1109/UHF.1999.787915","url":null,"abstract":"The triode with virtual cathode (VC) generates gigawatt pulses in a wide frequency band. Basically, existing theoretical investigations of this system were carried by method of numerical simulation and not did explain many experimental facts. The analytical description is more successful for description of generation mechanism. It allows one to find the main dependencies of frequency spectrum and generation efficiency on parameters of the VC triode and resonant system. It makes it possible to build high-efficiency devices.","PeriodicalId":348319,"journal":{"name":"Proceedings International University Conference 'Electronics and Radiophysics of Ultra-High Frequencies' (Cat. No.99EX356)","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121975636","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}
The investigations of noise-like oscillating processes in intensive electron beams, due to the presence of virtual cathodes (VC), have been producing great interest. The forming of oscillating VC in beams of charges is a complex process in which the nonlinear behavior of space charge is displayed. The difficulties of describing such systems exists due to the processes of intensive interaction between the electron beam collecting degree of freedom and developed space charge. The examining system consists of two grids (O-type diode). On the first grid the unmodulated monospeed beam is featured. The ability of creating behavior of acceleration or braking exists through the different second grid potential supply. Virtual cathode was developed by the effect of space charge.
{"title":"Dynamical chaos in the systems interaction of charged particles (computer simulations and experiment)","authors":"U.A. Kalinin, V. Kozhevnikov, A.G. Laserson","doi":"10.1109/UHF.1999.787933","DOIUrl":"https://doi.org/10.1109/UHF.1999.787933","url":null,"abstract":"The investigations of noise-like oscillating processes in intensive electron beams, due to the presence of virtual cathodes (VC), have been producing great interest. The forming of oscillating VC in beams of charges is a complex process in which the nonlinear behavior of space charge is displayed. The difficulties of describing such systems exists due to the processes of intensive interaction between the electron beam collecting degree of freedom and developed space charge. The examining system consists of two grids (O-type diode). On the first grid the unmodulated monospeed beam is featured. The ability of creating behavior of acceleration or braking exists through the different second grid potential supply. Virtual cathode was developed by the effect of space charge.","PeriodicalId":348319,"journal":{"name":"Proceedings International University Conference 'Electronics and Radiophysics of Ultra-High Frequencies' (Cat. No.99EX356)","volume":"82 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122475579","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}
V. Manuilov, M. Moiseev, A. Skryabin, N. A. Zavolsky
The efficiency estimates of multistage electron energy recovery systems are important for gyrotrons operated at the first and second cyclotron harmonics. The development of multistage energy recovery systems requires knowledge of the electron energy spectra F(W) after the interaction with RF field. In this paper the numerical calculation of F(W) was carried out by the method of big particles on the basis of theory of gyrotron with non-fixed RF field structure taking into account the electron oscillatory velocity spread. Gaussian function of oscillatory velocity distribution at the working space entrance was used.
{"title":"Efficiency of energy recovery multistage systems in gyrotrons","authors":"V. Manuilov, M. Moiseev, A. Skryabin, N. A. Zavolsky","doi":"10.1109/UHF.1999.787899","DOIUrl":"https://doi.org/10.1109/UHF.1999.787899","url":null,"abstract":"The efficiency estimates of multistage electron energy recovery systems are important for gyrotrons operated at the first and second cyclotron harmonics. The development of multistage energy recovery systems requires knowledge of the electron energy spectra F(W) after the interaction with RF field. In this paper the numerical calculation of F(W) was carried out by the method of big particles on the basis of theory of gyrotron with non-fixed RF field structure taking into account the electron oscillatory velocity spread. Gaussian function of oscillatory velocity distribution at the working space entrance was used.","PeriodicalId":348319,"journal":{"name":"Proceedings International University Conference 'Electronics and Radiophysics of Ultra-High Frequencies' (Cat. No.99EX356)","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121721375","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}
N. Ginzburg, A. Sergeev, I. Zotova, V. Shpak, M. Yalandin, A. Phelps, A. Cross, S. M. Wiggins, V. Tarakanov
Gives the results of the experimental investigation of SR of intense subnanosecond electron bunches moving through a periodic waveguide and interacting with a backward propagating wave. These results are compared with results of the numerical simulations based on the particle-in-cell (PIC) code KARAT.
{"title":"Generation of powerful subnanosecond microwave pulses based on superradiance","authors":"N. Ginzburg, A. Sergeev, I. Zotova, V. Shpak, M. Yalandin, A. Phelps, A. Cross, S. M. Wiggins, V. Tarakanov","doi":"10.1109/UHF.1999.787914","DOIUrl":"https://doi.org/10.1109/UHF.1999.787914","url":null,"abstract":"Gives the results of the experimental investigation of SR of intense subnanosecond electron bunches moving through a periodic waveguide and interacting with a backward propagating wave. These results are compared with results of the numerical simulations based on the particle-in-cell (PIC) code KARAT.","PeriodicalId":348319,"journal":{"name":"Proceedings International University Conference 'Electronics and Radiophysics of Ultra-High Frequencies' (Cat. No.99EX356)","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123800450","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}
Passive millimetre wave imaging systems have been developed and their applications investigated at DERA Malvern for several years. In this paper the applications of passive millimetre wave imaging for the detection of exhaust gases is investigated. In principle, this is feasible over the whole of the millimetre wave band. DERA has developed the world's first mechanically scanning real-time passive millimetre wave imager for the Ka band, the lower frequency end of the millimetre wave band. Currently at W-band, DERA is developing a real time imager using MMIC electronics to build the compact focal plane receiver array. Recent developments in MMIC technologies are beginning to make possible development of real time passive millimetre wave imaging systems at the still higher frequencies of the F- and D-bands.
{"title":"Passive millimetre wave imaging and absorption from exhaust gases","authors":"N. Salmon","doi":"10.1109/UHF.1999.787991","DOIUrl":"https://doi.org/10.1109/UHF.1999.787991","url":null,"abstract":"Passive millimetre wave imaging systems have been developed and their applications investigated at DERA Malvern for several years. In this paper the applications of passive millimetre wave imaging for the detection of exhaust gases is investigated. In principle, this is feasible over the whole of the millimetre wave band. DERA has developed the world's first mechanically scanning real-time passive millimetre wave imager for the Ka band, the lower frequency end of the millimetre wave band. Currently at W-band, DERA is developing a real time imager using MMIC electronics to build the compact focal plane receiver array. Recent developments in MMIC technologies are beginning to make possible development of real time passive millimetre wave imaging systems at the still higher frequencies of the F- and D-bands.","PeriodicalId":348319,"journal":{"name":"Proceedings International University Conference 'Electronics and Radiophysics of Ultra-High Frequencies' (Cat. No.99EX356)","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125270374","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}
We present a new high-performance small-sized multi-beam device, called a rezotrod, for uniform volumetric heating of large-sized objects. It has the advantages of UHF devices (complete passage of a current, closed electrodynamics systems), and grid tubes (supply without modulation, small length electrostatic focusing). It also has its own distinctive advantages (stabilized amplitude of an UHF voltage in an output gap, independent generating contour).
{"title":"Rezotrod: opportunities of the solution of a problem of a uniform volumetric heating of large-sized objects","authors":"A. Bajkov, D. Petrov","doi":"10.1109/UHF.1999.787979","DOIUrl":"https://doi.org/10.1109/UHF.1999.787979","url":null,"abstract":"We present a new high-performance small-sized multi-beam device, called a rezotrod, for uniform volumetric heating of large-sized objects. It has the advantages of UHF devices (complete passage of a current, closed electrodynamics systems), and grid tubes (supply without modulation, small length electrostatic focusing). It also has its own distinctive advantages (stabilized amplitude of an UHF voltage in an output gap, independent generating contour).","PeriodicalId":348319,"journal":{"name":"Proceedings International University Conference 'Electronics and Radiophysics of Ultra-High Frequencies' (Cat. No.99EX356)","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125527856","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}
The modern computer technology does not work out the problem of broadband klystron amplifier design by itself. It needs for a good initial approach on the base of physical notions. To form a system of buncher cavity resonant frequencies and Q's, the problem of RF currents interaction in the drift spaces is especially important. This subject is considered in this paper and the remedies are determined for obtaining of a flat gain frequency response. At first the "skirtron" tuning system is used, then the second cavity is detuned down and a multiple-coupled network is formed near the first cavity. Some other possibilities are discussed.
{"title":"The tuning system of broadband klystron amplifier","authors":"Y. Besov","doi":"10.1109/UHF.1999.787866","DOIUrl":"https://doi.org/10.1109/UHF.1999.787866","url":null,"abstract":"The modern computer technology does not work out the problem of broadband klystron amplifier design by itself. It needs for a good initial approach on the base of physical notions. To form a system of buncher cavity resonant frequencies and Q's, the problem of RF currents interaction in the drift spaces is especially important. This subject is considered in this paper and the remedies are determined for obtaining of a flat gain frequency response. At first the \"skirtron\" tuning system is used, then the second cavity is detuned down and a multiple-coupled network is formed near the first cavity. Some other possibilities are discussed.","PeriodicalId":348319,"journal":{"name":"Proceedings International University Conference 'Electronics and Radiophysics of Ultra-High Frequencies' (Cat. No.99EX356)","volume":"77 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121043435","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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