S. Korovin, G. Mesyats, I. Pegel, S. Polevin, V. Tarakanov
It is demonstrated that pulse shortening occurring in the relativistic BWO at gigawatt power level is accompanied by the appearance of an explosive-emission plasma on the surface of the corrugated slow wave structure. Termination of microwave emission is explained in terms of absorption of the operating electromagnetic wave by electrons emitted from the plasma while the intensity of absorption is radically increased by the presence of positive ions emitted from the plasma.
{"title":"Mechanism of microwave pulse shortening in the relativistic backward wave oscillator","authors":"S. Korovin, G. Mesyats, I. Pegel, S. Polevin, V. Tarakanov","doi":"10.1109/UHF.1999.787923","DOIUrl":"https://doi.org/10.1109/UHF.1999.787923","url":null,"abstract":"It is demonstrated that pulse shortening occurring in the relativistic BWO at gigawatt power level is accompanied by the appearance of an explosive-emission plasma on the surface of the corrugated slow wave structure. Termination of microwave emission is explained in terms of absorption of the operating electromagnetic wave by electrons emitted from the plasma while the intensity of absorption is radically increased by the presence of positive ions emitted from the plasma.","PeriodicalId":348319,"journal":{"name":"Proceedings International University Conference 'Electronics and Radiophysics of Ultra-High Frequencies' (Cat. No.99EX356)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124180266","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 will consider here the influence of microscopic dimensions of field emitter array (FEA) components and their finite conductivity on RF electric field on the tip ending (and hence emission current). Several unusual effects exist in field emission structures at high frequencies, so we decompose our analysis into consideration of several model systems.
{"title":"Frequency dependence of field enhancement factor for field emission cathodes with finite conductivity","authors":"A. Galdetskiy","doi":"10.1109/UHF.1999.787948","DOIUrl":"https://doi.org/10.1109/UHF.1999.787948","url":null,"abstract":"We will consider here the influence of microscopic dimensions of field emitter array (FEA) components and their finite conductivity on RF electric field on the tip ending (and hence emission current). Several unusual effects exist in field emission structures at high frequencies, so we decompose our analysis into consideration of several model systems.","PeriodicalId":348319,"journal":{"name":"Proceedings International University Conference 'Electronics and Radiophysics of Ultra-High Frequencies' (Cat. No.99EX356)","volume":"143 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":"115214144","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}
In recent years the researches of various sources of microwave radiation with supercritical currents are actively investigated. Operation of these devices is based on virtual cathode (VC) formation in the interaction space. VC is the oscillating area with space charge potential close to a potential of an electron source. Appearance of VC results in strong modulation of the arriving electron beam and excitation of high-power oscillations. The design simplicity, ultra high level of radiation power, possibility of frequency tuning with modification of electron beam parameters has attracted significant interest in recent years. In the present work we consider a triode-like vircator. In this system the electron beam injects from a cathode surface, further it passes an accelerating potential and after transmitting through an anode grid, it arrives in equipotential interaction space. One of remarkable features of VC devices is the complex irregular character of output radiation in similar devices. The great success of the nonlinear dynamic systems theory in the recent years is the discovery of a strong connection between dynamical chaos and structure formation. It is very interesting to clarify the connection between the formation of structures in electron beam with VC and its complex dynamics. The understanding of this connection allows us to control generation regimes at the expense of action on electronic structures.
{"title":"Structure formation and control of electron beam dynamics in triode systems with virtual cathode","authors":"V. Anfinogentov","doi":"10.1109/UHF.1999.787906","DOIUrl":"https://doi.org/10.1109/UHF.1999.787906","url":null,"abstract":"In recent years the researches of various sources of microwave radiation with supercritical currents are actively investigated. Operation of these devices is based on virtual cathode (VC) formation in the interaction space. VC is the oscillating area with space charge potential close to a potential of an electron source. Appearance of VC results in strong modulation of the arriving electron beam and excitation of high-power oscillations. The design simplicity, ultra high level of radiation power, possibility of frequency tuning with modification of electron beam parameters has attracted significant interest in recent years. In the present work we consider a triode-like vircator. In this system the electron beam injects from a cathode surface, further it passes an accelerating potential and after transmitting through an anode grid, it arrives in equipotential interaction space. One of remarkable features of VC devices is the complex irregular character of output radiation in similar devices. The great success of the nonlinear dynamic systems theory in the recent years is the discovery of a strong connection between dynamical chaos and structure formation. It is very interesting to clarify the connection between the formation of structures in electron beam with VC and its complex dynamics. The understanding of this connection allows us to control generation regimes at the expense of action on electronic structures.","PeriodicalId":348319,"journal":{"name":"Proceedings International University Conference 'Electronics and Radiophysics of Ultra-High Frequencies' (Cat. No.99EX356)","volume":"1 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":"122693364","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}
In this paper one of the simplest models of electron beam with overcritical current in the plain diode has been proposed. The behaviour of this model, called a "cellular conveyer", is coincident to the computation data of electron beams with overcritical current.
{"title":"On the simple model of electron beam with overcritical current [in vircators]","authors":"A. Hramov, A. Koronovskii, V. Anfinogentov","doi":"10.1109/UHF.1999.787917","DOIUrl":"https://doi.org/10.1109/UHF.1999.787917","url":null,"abstract":"In this paper one of the simplest models of electron beam with overcritical current in the plain diode has been proposed. The behaviour of this model, called a \"cellular conveyer\", is coincident to the computation data of electron beams with overcritical current.","PeriodicalId":348319,"journal":{"name":"Proceedings International University Conference 'Electronics and Radiophysics of Ultra-High Frequencies' (Cat. No.99EX356)","volume":"7 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":"114147261","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 author discusses the electrodynamic and constructional problems involved in summing the output powers of low voltage klystrons. He shows that after the addition of the output powers of eight partial klystrons at the operating frequency 2450 MHz, taking into account the transmission coefficient of the common ring resonator, the output power of the multistream klystron can be determine and is found to be 250 kW.
{"title":"Summation of the output powers for the low voltage 2.45 GHz klystrons","authors":"V.S. Medovikov","doi":"10.1109/UHF.1999.787880","DOIUrl":"https://doi.org/10.1109/UHF.1999.787880","url":null,"abstract":"The author discusses the electrodynamic and constructional problems involved in summing the output powers of low voltage klystrons. He shows that after the addition of the output powers of eight partial klystrons at the operating frequency 2450 MHz, taking into account the transmission coefficient of the common ring resonator, the output power of the multistream klystron can be determine and is found to be 250 kW.","PeriodicalId":348319,"journal":{"name":"Proceedings International University Conference 'Electronics and Radiophysics of Ultra-High Frequencies' (Cat. No.99EX356)","volume":"504 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":"117040263","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}
Characteristics of a new all-in-one setup for experimental determination of electron beam parameters of high-power microwave O-type devices are given. The measurements were made in the collector part of the device, where the electron beam expanded in the absence of external electric or magnetic fields after interaction with the rf structure. The analyzing section was mounted to the microwave tube instead of the collector unit to measure spatial, angular and energy distributions of the electron beam.
{"title":"A diagnostic setup for measurement of time-resolved electron beam distributions in high-power O-type devices","authors":"A. Arkhipov, N.V. Dvoretskaja, G. Sominski","doi":"10.1109/UHF.1999.787925","DOIUrl":"https://doi.org/10.1109/UHF.1999.787925","url":null,"abstract":"Characteristics of a new all-in-one setup for experimental determination of electron beam parameters of high-power microwave O-type devices are given. The measurements were made in the collector part of the device, where the electron beam expanded in the absence of external electric or magnetic fields after interaction with the rf structure. The analyzing section was mounted to the microwave tube instead of the collector unit to measure spatial, angular and energy distributions of the electron beam.","PeriodicalId":348319,"journal":{"name":"Proceedings International University Conference 'Electronics and Radiophysics of Ultra-High Frequencies' (Cat. No.99EX356)","volume":"76 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":"124722550","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}
Study of space-charge phenomena in high-power microwave devices is for a long time considered to be one of primary objectives of High-Current and Microwave Electronics Laboratory of St. Petersburg State Technical University. In our practice, we use various diagnostic methods including standard, generally accepted ones. Three of our original techniques will be characterized in this paper. These techniques had been developed to yield information on space charge distribution and collective effects in systems with magnetic confinement and on transverse (relative to magnetic field vector) components of electron velocity in magnetized flows.
{"title":"Processes in space charge of high-power microwave devices: Diagnostics and control","authors":"G. Sominski","doi":"10.1109/UHF.1999.787938","DOIUrl":"https://doi.org/10.1109/UHF.1999.787938","url":null,"abstract":"Study of space-charge phenomena in high-power microwave devices is for a long time considered to be one of primary objectives of High-Current and Microwave Electronics Laboratory of St. Petersburg State Technical University. In our practice, we use various diagnostic methods including standard, generally accepted ones. Three of our original techniques will be characterized in this paper. These techniques had been developed to yield information on space charge distribution and collective effects in systems with magnetic confinement and on transverse (relative to magnetic field vector) components of electron velocity in magnetized flows.","PeriodicalId":348319,"journal":{"name":"Proceedings International University Conference 'Electronics and Radiophysics of Ultra-High Frequencies' (Cat. No.99EX356)","volume":"11 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":"129436759","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 suggested method is effective for simulation of very complicated fully 3D-electromagnetic structures with waveguide ports. It provides important information about the field distribution inside the structure as well as other parameters, which are necessarily for beam transport investigation. The high accuracy of computations and small time consumption allows one to carry out electromagnetic design of high power microwave devices on personal computers.
{"title":"Numerical simulation of high power klystron output systems","authors":"S. Silaev","doi":"10.1109/UHF.1999.787974","DOIUrl":"https://doi.org/10.1109/UHF.1999.787974","url":null,"abstract":"The suggested method is effective for simulation of very complicated fully 3D-electromagnetic structures with waveguide ports. It provides important information about the field distribution inside the structure as well as other parameters, which are necessarily for beam transport investigation. The high accuracy of computations and small time consumption allows one to carry out electromagnetic design of high power microwave devices on personal computers.","PeriodicalId":348319,"journal":{"name":"Proceedings International University Conference 'Electronics and Radiophysics of Ultra-High Frequencies' (Cat. No.99EX356)","volume":"24 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":"121135693","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}
Many years of plasma electronics development has led to powerful microwave devices creation. Due to use of plasma-filled electromagnetic structures these devices exhibit significant increase of efficiency, power and radiation bandwidth. Plasma-filled traveling-wave oscillators have been developed and studied. Special investigations of low frequency plasma oscillations, which appear in the powerful plasma-filled microwave devices, have been carried out. Such oscillations are one of the possible reasons for microwave generation pulse shortening. The usual premise of many investigations of beam-plasma instability is the assumption of independence of plasma parameters from microwave power. However various reasons for a dependence exist and the main are high frequency pressure (HFP) and high frequency discharge. Both these reasons lead to the appearance of a plasma longitudinal inhomogeneity. The resonance character of a beam-wave interaction makes it very sensitive to the inhomogeneity of the medium where the wave is propagated. Experiments are described which show that the role of HFP in increasing microwave power growth. It is confirmed by the large difference between plasma densities near the input and output ends of the system.
{"title":"Plasma electronics. Theoretical and experimental investigations of plasma nonlinearity in the traveling-wave tube oscillators","authors":"Y. Bliokh","doi":"10.1109/UHF.1999.787952","DOIUrl":"https://doi.org/10.1109/UHF.1999.787952","url":null,"abstract":"Many years of plasma electronics development has led to powerful microwave devices creation. Due to use of plasma-filled electromagnetic structures these devices exhibit significant increase of efficiency, power and radiation bandwidth. Plasma-filled traveling-wave oscillators have been developed and studied. Special investigations of low frequency plasma oscillations, which appear in the powerful plasma-filled microwave devices, have been carried out. Such oscillations are one of the possible reasons for microwave generation pulse shortening. The usual premise of many investigations of beam-plasma instability is the assumption of independence of plasma parameters from microwave power. However various reasons for a dependence exist and the main are high frequency pressure (HFP) and high frequency discharge. Both these reasons lead to the appearance of a plasma longitudinal inhomogeneity. The resonance character of a beam-wave interaction makes it very sensitive to the inhomogeneity of the medium where the wave is propagated. Experiments are described which show that the role of HFP in increasing microwave power growth. It is confirmed by the large difference between plasma densities near the input and output ends of the system.","PeriodicalId":348319,"journal":{"name":"Proceedings International University Conference 'Electronics and Radiophysics of Ultra-High Frequencies' (Cat. No.99EX356)","volume":"129 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":"114540152","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 authors present a new unified approach to designing multi-cavity klystron amplifiers and an algorithm for the synthesis of such devices is given and proved. Although the offered concept of synthesis is formally contradictory (a partial approach to nonlinear systems), it practically completely corresponds to modem methods of system engineering and can be formulated in terms of the system approach as an optimum design within the synthesis. The experiments confirm this to be the case.
{"title":"On a new approach to designing of wideband klystron amplifiers","authors":"Y.L. Bobrovsky, A. Gavrilenko, S. Rudakov","doi":"10.1109/UHF.1999.787868","DOIUrl":"https://doi.org/10.1109/UHF.1999.787868","url":null,"abstract":"The authors present a new unified approach to designing multi-cavity klystron amplifiers and an algorithm for the synthesis of such devices is given and proved. Although the offered concept of synthesis is formally contradictory (a partial approach to nonlinear systems), it practically completely corresponds to modem methods of system engineering and can be formulated in terms of the system approach as an optimum design within the synthesis. The experiments confirm this to be the case.","PeriodicalId":348319,"journal":{"name":"Proceedings International University Conference 'Electronics and Radiophysics of Ultra-High Frequencies' (Cat. No.99EX356)","volume":"80 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":"121609899","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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