Proceedings of the 17th IEEE International Vacuum Electronics Conference (IVEC-2016)
An approximate model of discrete multibeam generator based on the use of equivalent oscillators is offered. Formation of the antenna radiation field in a three-dimensional approach on the example of a cylindrical ring radiator is considered. Each ring consists of a large number of dipoles oriented in a longitudinal direction. It is shown that the type of pattern depends on the ratio of the phase velocity of waves excitation dipoles to the speed of light.
Macroscopic quantum interaction processes of ring systems of electron and positron macroplasmoid taking into account fields of vector potential are investigated. The non-stationary self-consistent problem of the charged particles movement taking into account interaction of wave fields, Coulomb forces and a magnetic field is solved.
IVEC 2013 is intended to be a forum of information and discussion between the various players in the field of vacuum electronics: device users, manufacturers and operators, government/institutions, academics, and students. Submissions from all groups are encouraged. IVEC 2013 will provide the right place for the exchange of scientific and technical information and will foster collaboration and cooperation in the vacuum electronics domain both at European and worldwide level.
IVEC was originally created in 2000 by merging the U.S. Power Tubes Conferences and the European Space Agency TWTA Workshops. Now a fully international conference, IVEC is held every other year in the U.S., and in Europe and Asia alternately every fourth year. After the successful and enjoyable meeting in Paris, France in May, IVEC 2014 will return to its beautiful U.S. location in the city of Monterey.
The TWT model based on placed in parallel impedance electrodes is used to analyze effectiveness of a sheet e-beam interaction with the in-phase mode of a slow wave excited in the impedance electrodes. The impedance approximation was used for presentation fields of E- and H-waves by zero and ±1 space harmonics, respectively. The generalized formula for the coupling coefficient, characterizing the interaction effectiveness, was used to demonstrate the its dependence on the e-beam thickness and the gaps between the impedance and screen electrodes. The obtained dependences on the e-beam tunnel geometry and the operating frequency were compared with that calculated for a cylindrical beam in a conventional helix.
A method of analysis of beam-wave interaction in passbands and stopbands of periodic slow-wave systems (SWS), based on the use of the finite-difference equation of excitation of such systems by an electron beam, is presented. In contrast to equations of a well-known beam wave interaction theory it includes the local coupling impedance, that characterizes the interaction of electrons with the total field of two waves (forward and counter-propagating) of the slow- wave system and does not tend to infinity at cutoff frequencies. It allowed to develop a general theory of interaction of electron beams and waves in passbands and stopbands of slow-wave systems without using their equivalent circuits. A study of beam wave interaction in the folded waveguide-type SWSs has been performed. An elementary analytical calculation of electro-dynamic characteristics of such SWSs necessary to study the interaction is given. Specifies of interaction in passbands and near cutoff frequencies of periodic SWSs are considered. Amplification conditions in stopbands of such slow-wave systems are discovered. Properties of the beam-wave interaction at the cutoff frequency where the folded waveguide is an analog of multi-gap open resonators used in such electron devices, as an orotron, are examined.
In this study with using of the small-signal theory of discrete electron-wave interaction in the passbands and stopbands resonator slow-wave systems (SWS) of power traveling-wave tubes (TWT), obtain the characteristic equation for the propagation constants of the 4-electron waves produced in the interaction of the electron beam forward and backward electromagnetic waves of SWS. The analysis of solutions of this equation, which allowed to establish the specific characteristics of these waves are compared with the known properties of electron waves in a "smooth", such as helical SWS. On the basis of solving the boundary value problem for the SWS segments were simulated and found gain of multisection TWT with transparent section and stopsection, as well as, the distribution of fields and currents along the stopsection.
In the study presents an approach to the modeling power TWT with stopband sections on the basis of the theory of discrete electron-wave interaction. Designed TWT without the use of equivalent circuits of SWS and with use of local coupling impedance and the characteristic equation of degree four.
The fourth power algebraic characteristic equation is obtained for the wave number of the individual electron waves that exist in periodic slow-wave systems(SWS) with discrete electron-wave interaction. The study of properties of these waves and the solution of the corresponding boundary-value problem have been performed. It has allowed to find some properties of electron-wave interaction which are different or are identical to the SWS with discrete interactions or "smooth" SWS, for example helical SWS.
The model based on coupled impedance electrodes was used to analyze effectiveness of a sheet e-beam interaction with the in-phase mode of a slow wave. The coupling coefficient, characterizing the interaction effectiveness, was calculated using derivatives of the equivalent parameters, the specific capacitances and inductance. The calculated coefficient was compared with that of a cylindrical e-beam in a helix.
Generalized error-locating codes are discussed. An algorithm for calculation of the upper bound of the probability of erroneous decoding for known code parameters and the input error probability is given. Based on this algorithm, an algorithm for selection of the code parameters for a specified design and input and output error probabilities is constructed. The lower bound of the probability of erroneous decoding is given. Examples of the dependence of the probability of erroneous decoding on the input error probability are given and the behavior of the obtained curves is explained.
The dynamics of a two-component Davydov-Scott (DS) soliton with a small mismatch of the initial location or velocity of the high-frequency (HF) component was investigated within the framework of the Zakharov-type system of two coupled equations for the HF and low-frequency (LF) fields. In this system, the HF field is described by the linear Schrödinger equation with the potential generated by the LF component varying in time and space. The LF component in this system is described by the Korteweg-de Vries equation with a term of quadratic influence of the HF field on the LF field. The frequency of the DS soliton`s component oscillation was found analytically using the balance equation. The perturbed DS soliton was shown to be stable. The analytical results were confirmed by numerical simulations.
By using superconducting quantum interference device (SQUID) magnetometry, we investigated anisotropic high-field (H less than or similar to 7T) low-temperature (10 K) magnetization response of inhomogeneous nanoisland FeNi films grown by rf sputtering deposition on Sitall (TiO2) glass substrates. In the grown FeNi films, the FeNi layer nominal thickness varied from 0.6 to 2.5 nm, across the percolation transition at the d(c) similar or equal to 1.8 nm. We discovered that, beyond conventional spin-magnetism of Fe21Ni79 permalloy, the extracted out-of-plane magnetization response of the nanoisland FeNi films is not saturated in the range of investigated magnetic fields and exhibits paramagnetic-like behavior. We found that the anomalous out-of-plane magnetization response exhibits an escalating slope with increase in the nominal film thickness from 0.6 to 1.1 nm, however, it decreases with further increase in the film thickness, and then practically vanishes on approaching the FeNi film percolation threshold. At the same time, the in-plane response demonstrates saturation behavior above 1.5-2T, competing with anomalously large diamagnetic-like response, which becomes pronounced at high magnetic fields. It is possible that the supported-metal interaction leads to the creation of a thin charge-transfer (CT) layer and a Schottky barrier at the FeNi film/Sitall (TiO2) interface. Then, in the system with nanoscale circular domains, the observed anomalous paramagnetic-like magnetization response can be associated with a large orbital moment of the localized electrons. In addition, the inhomogeneous nanoisland FeNi films can possess spontaneous ordering of toroidal moments, which can be either of orbital or spin origin. The system with toroidal inhomogeneity can lead to anomalously strong diamagnetic-like response. The observed magnetization response is determined by the interplay between the paramagnetic-and diamagnetic-like contributions.
This volume presents new results in the study and optimization of information transmission models in telecommunication networks using different approaches, mainly based on theiries of queueing systems and queueing networks .
The paper provides a number of proposed draft operational guidelines for technology measurement and includes a number of tentative technology definitions to be used for statistical purposes, principles for identification and classification of potentially growing technology areas, suggestions on the survey strategies and indicators. These are the key components of an internationally harmonized framework for collecting and interpreting technology data that would need to be further developed through a broader consultation process. A summary of definitions of technology already available in OECD manuals and the stocktaking results are provided in the Annex section.