DEFF Research Database (Denmark)
This book is dedicated to various aspects of electromagnetic wave theory and its applications in science and technology. The covered topics include the fundamental physics of electromagnetic waves, theory of electromagnetic wave propagation and scattering, methods of computational analysis......, material characterization, electromagnetic properties of plasma, analysis and applications of periodic structures and waveguide components, etc....
Kaliski, S
2013-01-01
This book gives a comprehensive overview of wave phenomena in different media with interacting mechanical, electromagnetic and other fields. Equations describing wave propagation in linear and non-linear elastic media are followed by equations of rheological models, models with internal rotational degrees of freedom and non-local interactions. Equations for coupled fields: thermal, elastic, electromagnetic, piezoelectric, and magneto-spin with adequate boundary conditions are also included. Together with its companion volume Vibrations and Waves. Part A: Vibrations this work provides a wealth
Electromagnetic wave matching device
International Nuclear Information System (INIS)
Hirata, Yosuke; Mitsunaka, Yoshika; Hayashi, Ken-ichi; Ito, Yasuyuki.
1997-01-01
The present invention provides an electromagnetic wave matching capable of reducing a cost for the transmission system in a system of using electromagnetic waves for plasma heating of a thermonuclear reactor. Namely, incident electromagnetic waves are reflected by using a plurality of phase correction mirrors. The reflected electromagnetic waves are connected to an external transmission system through an exit. The phase correction mirrors have such a shape to receive a plurality of beam-like electromagnetic waves and output electromagnetic waves by the number different from the number of the received electromagnetic wave beams having a predetermined distribution. Further, at least two of the phase correction mirrors have such a shape to change the phase of the electromagnetic waves beams incident to the reflection surface of the phase correction mirrors by a predetermined amount corresponding to the position of the reflection surface. Then, the cost for transmission system can greatly be reduced. (I.S.)
Electromagnetic ultrasonic guided waves
Huang, Songling; Li, Weibin; Wang, Qing
2016-01-01
This book introduces the fundamental theory of electromagnetic ultrasonic guided waves, together with its applications. It includes the dispersion characteristics and matching theory of guided waves; the mechanism of production and theoretical model of electromagnetic ultrasonic guided waves; the effect mechanism between guided waves and defects; the simulation method for the entire process of electromagnetic ultrasonic guided wave propagation; electromagnetic ultrasonic thickness measurement; pipeline axial guided wave defect detection; and electromagnetic ultrasonic guided wave detection of gas pipeline cracks. This theory and findings on applications draw on the author’s intensive research over the past eight years. The book can be used for nondestructive testing technology and as an engineering reference work. The specific implementation of the electromagnetic ultrasonic guided wave system presented here will also be of value for other nondestructive test developers.
Electromagnetic cyclotron harmonic waves
International Nuclear Information System (INIS)
Ohnuma, T.; Watanabe, T.; Hamamatsu, K.
1981-09-01
Electromagnetic electron cyclotron harmonic waves just below the electron cyclotron harmonics are investigated numerically and experimentally. Backward waves which are observed to propagate nearly perpendicular to the magnetic field just below the electron cyclotron frequency in a high density magnetoplasma are confirmed to be in accord with the theoretical electromagnetic cyclotron waves. (author)
Electromagnetic wave matching device
International Nuclear Information System (INIS)
Hirata, Yosuke; Mitsunaka, Yoshika; Hayashi, Ken-ichi; Ito, Yasuyuki.
1997-01-01
The present invention provides a matching device capable of increasing an efficiency of combining beams of electromagnetic waves outputted from an output window of a gyrotron which is expected for plasma heating of a thermonuclear reactor and an electromagnetic wave transmission system as high as possible. Namely, an electromagnetic wave matching device reflects beams of electromagnetic waves incident from an inlet by a plurality of phase correction mirrors and combines them to an external transmission system through an exit. In this case, the phase correction mirrors change the phase of the beams of electromagnetic waves incident to the phase correction mirrors by a predetermined amount corresponding to the position of the reflection mirrors. Then, the beams of electromagnetic waves outputted, for example, from a gyrotron can properly be shaped as desired for the intensity and the phase. As a result, combination efficiency with the transmission system can be increased. (I.S.)
Electromagnetic wave energy converter
Bailey, R. L. (Inventor)
1973-01-01
Electromagnetic wave energy is converted into electric power with an array of mutually insulated electromagnetic wave absorber elements each responsive to an electric field component of the wave as it impinges thereon. Each element includes a portion tapered in the direction of wave propagation to provide a relatively wideband response spectrum. Each element includes an output for deriving a voltage replica of the electric field variations intercepted by it. Adjacent elements are positioned relative to each other so that an electric field subsists between adjacent elements in response to the impinging wave. The electric field results in a voltage difference between adjacent elements that is fed to a rectifier to derive dc output power.
"Hearing" Electromagnetic Waves
Rojo, Marta; Munoz, Juan
2014-01-01
In this work, an educational experience is described in which a microwave communication link is used to make students aware that all electromagnetic waves have the same physical nature and properties. Experimental demonstrations are linked to theoretical concepts to increase comprehension of the physical principles underlying electromagnetic…
Wave fronts of electromagnetic cyclotron harmonic waves
International Nuclear Information System (INIS)
Ohnuma, T.; Watanabe, T.
1982-01-01
In an inhomogeneous high-density magnetized plasma, the spatial properties of the wave fronts and ray trajectories of electromagnetic ordinary and extraordinary cyclotron harmonic waves are investigated. Those waves which are radiated from a local source are found to have wave fronts which are almost parallel to the magnetic field. Also, the reflective properties of the electromagnetic cyclotron harmonic waves are confirmed
Metamaterial electromagnetic wave absorbers.
Watts, Claire M; Liu, Xianliang; Padilla, Willie J
2012-06-19
The advent of negative index materials has spawned extensive research into metamaterials over the past decade. Metamaterials are attractive not only for their exotic electromagnetic properties, but also their promise for applications. A particular branch-the metamaterial perfect absorber (MPA)-has garnered interest due to the fact that it can achieve unity absorptivity of electromagnetic waves. Since its first experimental demonstration in 2008, the MPA has progressed significantly with designs shown across the electromagnetic spectrum, from microwave to optical. In this Progress Report we give an overview of the field and discuss a selection of examples and related applications. The ability of the MPA to exhibit extreme performance flexibility will be discussed and the theory underlying their operation and limitations will be established. Insight is given into what we can expect from this rapidly expanding field and future challenges will be addressed. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Electromagnetic fields and waves
Iskander, Magdy F
2013-01-01
The latest edition of Electromagnetic Fields and Waves retains an authoritative, balanced approach, in-depth coverage, extensive analysis, and use of computational techniques to provide a complete understanding of electromagnetic—important to all electrical engineering students. An essential feature of this innovative text is the early introduction of Maxwell's equations, together with the quantifying experimental observations made by the pioneers who discovered electromagnetics. This approach directly links the mathematical relations in Maxwell's equations to real experiments and facilitates a fundamental understanding of wave propagation and use in modern practical applications, especially in today's wireless world. New and expanded topics include the conceptual relationship between Coulomb's law and Gauss's law for calculating electric fields, the relationship between Biot-Savart's and Ampere's laws and their use in calculating magnetic fields from current sources, the development of Faraday's law from e...
Wave propagation in electromagnetic media
International Nuclear Information System (INIS)
Davis, J.L.
1990-01-01
This book is concerned with wave propagation in reacting media, specifically in electromagnetic materials. An account is presented of the mathematical methods of wave phenomena in electromagnetic materials. The author presents the theory of time-varying electromagnetic fields, which involves a discussion of Faraday's laws, Maxwell's equations and their application to electromagnetic wave propagation under a variety of conditions. The author gives a discussion of magnetohydrodynamics and plasma physics. Chapters are included on quantum mechanics and the theory of relativity. The mathematical foundation of electromagnetic waves vis a vis partial differential equations is discussed
A first course in vibrations and waves
Samiullah, Mohammad
2015-01-01
This book builds on introductory physics and emphasizes understanding of vibratory motion and waves based on first principles. The book is divided into three parts. Part I contains a preliminary chapter that serves as a review of relevant ideas of mechanics and complex numbers. Part II is devoted to a detailed discussion of vibrations of mechanical systems. This part covers a simple harmonic oscillator, coupled oscillators, normal coordinates, beaded string, continuous string, standing waves, and Fourier series. Part II ends with a presentation of stationary solutions of driven finite systems. Part III is concerned with waves. Here, the emphasis is on the discussion of common aspects of all types of waves. The applications to sound, electromagnetic, and matter waves are illustrated. The book also includes examples from water waves and electromagnetic waves on a transmission line. The emphasis of the book is to bring out the similarities among various types of waves. The book includes treatment of reflection a...
Electromagnetic waves in stratified media
Wait, James R; Fock, V A; Wait, J R
2013-01-01
International Series of Monographs in Electromagnetic Waves, Volume 3: Electromagnetic Waves in Stratified Media provides information pertinent to the electromagnetic waves in media whose properties differ in one particular direction. This book discusses the important feature of the waves that enables communications at global distances. Organized into 13 chapters, this volume begins with an overview of the general analysis for the electromagnetic response of a plane stratified medium comprising of any number of parallel homogeneous layers. This text then explains the reflection of electromagne
Wave propagation in electromagnetic media
Davis, Julian L
1990-01-01
This is the second work of a set of two volumes on the phenomena of wave propagation in nonreacting and reacting media. The first, entitled Wave Propagation in Solids and Fluids (published by Springer-Verlag in 1988), deals with wave phenomena in nonreacting media (solids and fluids). This book is concerned with wave propagation in reacting media-specifically, in electro magnetic materials. Since these volumes were designed to be relatively self contained, we have taken the liberty of adapting some of the pertinent material, especially in the theory of hyperbolic partial differential equations (concerned with electromagnetic wave propagation), variational methods, and Hamilton-Jacobi theory, to the phenomena of electromagnetic waves. The purpose of this volume is similar to that of the first, except that here we are dealing with electromagnetic waves. We attempt to present a clear and systematic account of the mathematical methods of wave phenomena in electromagnetic materials that will be readily accessi...
Focusing of electromagnetic waves
International Nuclear Information System (INIS)
Dhayalan, V.
1996-01-01
The focusing of electromagnetic waves inside a slab has been examined together with two special cases in which the slab is reduced to a single interface or a single medium. To that end the exact solutions for the fields inside a layered medium have been used, given in terms of the outside current source in order to obtain the solutions for the focused electric field inside a slab. Both exact and asymptotic solutions of the problem have been considered, and the validity of the latter has been discussed. The author has developed a numerical algorithm for evaluation of the diffraction integral with special emphasis on reducing the computing time. The numerical techniques in the paper can be readily applied to evaluate similar diffraction integrals occurring e.g. in microstrip antennas. 46 refs
Electromagnetic waves in gravitational wave spacetimes
International Nuclear Information System (INIS)
Haney, M.; Bini, D.; Ortolan, A.; Fortini, P.
2013-01-01
We have considered the propagation of electromagnetic waves in a space-time representing an exact gravitational plane wave and calculated the induced changes on the four-potential field Aμ of a plane electromagnetic wave. By choosing a suitable photon round-trip in a Michelson interferometer, we have been able to identify the physical effects of the exact gravitational wave on the electromagnetic field, i.e. phase shift, change of the polarization vector, angular deflection and delay. These results have been exploited to study the response of an interferometric gravitational wave detector beyond the linear approximation of the general theory of relativity. A much more detailed examination of this problem can be found in our paper recently published in Classical and Quantum Gravity (28 (2011) 235007).
Electromagnetic Vibration Energy Harvesting for Railway Applications
Directory of Open Access Journals (Sweden)
Bradai S.
2018-01-01
Full Text Available Safe localization of trains via GPS and wireless sensors is essential for railway traffic supervision. Especially for freight trains and because normally no power source is available on the wagons, special solutions for energy supply have to be developed based on energy harvesting techniques. Since vibration is available in this case, it provides an interesting source of energy. Nevertheless, in order to have an efficient design of the harvesting system, the existing vibration needs to be investigated. In this paper, we focus on the characterization of vibration parameters in railway application. We propose an electromagnetic vibration converter especially developed to this application. Vibration profiles from a train traveling between two German cities were measured using a data acquisition system installed on the train’s wagon. Results show that the measured profiles present multiple frequency signals in the range of 10 to 50 Hz and an acceleration of up to 2 g. A prototype for a vibration converter is designed taking into account the real vibration parameters, robustness and integrability requirements. It is based on a moving coil attached to a mechanical spring. For the experimental emulation of the train vibrations, a shaker is used as an external artificial vibration source controlled by a laser sensor in feedback. A maximum voltage of 1.7 V peak to peak which corresponds to a maximum of 10 mW output power where the applied excitation frequency is close to the resonant frequency of the converter which corresponds to 27 Hz.
Electromagnetic resonance waves
International Nuclear Information System (INIS)
Villaba, J.M.; Manjon, F.J.; Guirao, A.; Andres, M.V.
1994-01-01
We describe in this paper a set of experiments designed to make qualitative and quantitative measurements on electromagnetic resonances of several simple systems. The experiments are designed for the undergraduate laboratory of Electricity and Magnetism in Physics. These experiments can help the students understanding the concept of resonance, which appears in different fields of Physics. (Author) 8 refs
Radiation and propagation of electromagnetic waves
Tyras, George; Declaris, Nicholas
1969-01-01
Radiation and Propagation of Electromagnetic Waves serves as a text in electrical engineering or electrophysics. The book discusses the electromagnetic theory; plane electromagnetic waves in homogenous isotropic and anisotropic media; and plane electromagnetic waves in inhomogenous stratified media. The text also describes the spectral representation of elementary electromagnetic sources; the field of a dipole in a stratified medium; and radiation in anisotropic plasma. The properties and the procedures of Green's function method of solution, axial currents, as well as cylindrical boundaries a
Forerunners of electromagnetic waves
International Nuclear Information System (INIS)
Gendenshtejn, L.Eh.; Polovin, R.V.
1980-01-01
The given paper is a review. Considered are forerunners at the sudden switching the signal in the medium with frequency dispersion. The consideration is carried out by the pass method. Described are the first and the second forerunners, as well as the momentum of the main signal coming. It is noted, that in the case of the active medium the second forerunner, connected with eigen medium vibrations, can grow
Proposed electromagnetic wave energy converter
Bailey, R. L.
1973-01-01
Device converts wave energy into electric power through array of insulated absorber elements responsive to field of impinging electromagnetic radiation. Device could also serve as solar energy converter that is potentially less expensive and fragile than solar cells, yet substantially more efficient.
Geometry of wave electromagnetics
Energy Technology Data Exchange (ETDEWEB)
Sudarshan, E. C.G.
1980-10-27
A challenge to the commonly held view of light as a wave phenomenon is presented. An exact realization of light as generalized pencils or rays is constructed, with stress placed on using pencils of rays rather than single rays. Exact equations of motion are presented for the rays in the pencil, and these rays tend to travel in straight lines in empty space (not too near the edge of the beam). (GHT)
Millimeter waves: acoustic and electromagnetic.
Ziskin, Marvin C
2013-01-01
This article is the presentation I gave at the D'Arsonval Award Ceremony on June 14, 2011 at the Bioelectromagnetics Society Annual Meeting in Halifax, Nova Scotia. It summarizes my research activities in acoustic and electromagnetic millimeter waves over the past 47 years. My earliest research involved acoustic millimeter waves, with a special interest in diagnostic ultrasound imaging and its safety. For the last 21 years my research expanded to include electromagnetic millimeter waves, with a special interest in the mechanisms underlying millimeter wave therapy. Millimeter wave therapy has been widely used in the former Soviet Union with great reported success for many diseases, but is virtually unknown to Western physicians. I and the very capable members of my laboratory were able to demonstrate that the local exposure of skin to low intensity millimeter waves caused the release of endogenous opioids, and the transport of these agents by blood flow to all parts of the body resulted in pain relief and other beneficial effects. Copyright © 2012 Wiley Periodicals, Inc.
Production of gravitation waves by electromagnetic radiation
International Nuclear Information System (INIS)
Buchner, K.; Rosca, R.
1980-01-01
An exact solution of Einstein's equations is presented that corresponds to an axisymmetric bundle of electromagnetic waves with finite cross section. Outside this bundle, there is gravitational radiation parallel to the electromagnetic radiation. If no static electromagnetic fields are present, the frequency of the gravitational waves is twice the frequency of the electromagnetic waves. Einstein's energy complex vanishes identically. The covariant energy complex, however, yields also a radial momentum. (author)
Interacting electromagnetic waves in general relativity
International Nuclear Information System (INIS)
Griffiths, J.B.
1976-01-01
The problem is considered of finding exact solutions of the Einstein-Maxwell equations which describe the physical situation of two colliding and subsequently interacting electromagnetic waves. The general theory of relativity predicts a nonlinear interaction between electromagnetic waves. The situation is described using an approximate geometrical method, and a new exact solution describing two interacting electromagnetic waves is given. This describes waves emitted from two sources mutually focusing each other on the opposite source. (author)
Radiation Safety of Electromagnetic Waves
International Nuclear Information System (INIS)
Hussein, A.Z.
2009-01-01
The wide spread of Electromagnetic Waves (EMW) through the power lines, multimedia, communications, devices, appliances, etc., are well known. The probable health hazards associated with EMW and the radiation safety criteria are to be reviewed. However, the principles of the regulatory safety are based on radiation protection procedure, intervention to combat the relevant risk and to mitigate consequences. The oscillating electric magnetic fields (EMF) of the electromagnetic radiation (EMR) induce electrical hazards. The extremely high power EMR can cause fire hazards and explosions of pyrotechnic (Rad Haz). Biological hazards of EMF result as dielectric heat, severe burn, as well as the hazards of eyes. Shielding is among the technical protective measures against EMR hazards. Others are limitation of time of exposure and separation distance apart of the EMR source. Understanding and safe handling of the EMR sources are required to feel safety.
Science 101: Can Electromagnetic Waves Affect Emotions?
Robertson, Bill
2017-01-01
The answer to this month's question, "Can electromagnetic waves affect emotions," is yes. Wherever there are electromagnetic (EM) waves (basically everywhere!), there is the potential for them directly or indirectly to affect the emotions. But what about the likely motivation behind the originally-posed question? Can EM waves affect your…
Generating gravity waves with matter and electromagnetic waves
International Nuclear Information System (INIS)
Barrabes, C.; Hogan, P A.
2008-01-01
If a homogeneous plane lightlike shell collides head on with a homogeneous plane electromagnetic shock wave having a step-function profile then no backscattered gravitational waves are produced. We demonstrate, by explicit calculation, that if the matter is accompanied by a homogeneous plane electromagnetic shock wave with a step-function profile then backscattered gravitational waves appear after the collision
Introduction to vibrations and waves
Pain, H John
2015-01-01
Based on the successful multi-edition book "The Physics ofVibrations and Waves" by John Pain, the authors carry overthe simplicity and logic of the approach taken in the originalfirst edition with its focus on the patterns underlying andconnecting so many aspects of physical behavior, whilst bringingthe subject up-to-date so it is relevant to teaching in the21st century.The transmission of energy by wave propagation is a key conceptthat has applications in almost every branch of physics withtransmitting mediums essentially acting as a continuum of coupledoscillators. The characterization of t
International Nuclear Information System (INIS)
Sati, Priti; Tripathi, V. K.
2012-01-01
Parametric decay of a large amplitude electromagnetic wave into two electromagnetic modes in a rippled density plasma channel is investigated. The channel is taken to possess step density profile besides a density ripple of axial wave vector. The density ripple accounts for the momentum mismatch between the interacting waves and facilitates nonlinear coupling. For a given pump wave frequency, the requisite ripple wave number varies only a little w.r.t. the frequency of the low frequency decay wave. The radial localization of electromagnetic wave reduces the growth rate of the parametric instability. The growth rate decreases with the frequency of low frequency electromagnetic wave.
Electromagnetic wave energy conversion research
Bailey, R. L.; Callahan, P. S.
1975-01-01
Known electromagnetic wave absorbing structures found in nature were first studied for clues of how one might later design large area man-made radiant-electric converters. This led to the study of the electro-optics of insect dielectric antennae. Insights were achieved into how these antennae probably operate in the infrared 7-14um range. EWEC theoretical models and relevant cases were concisely formulated and justified for metal and dielectric absorber materials. Finding the electromagnetic field solutions to these models is a problem not yet solved. A rough estimate of losses in metal, solid dielectric, and hollow dielectric waveguides indicates future radiant-electric EWEC research should aim toward dielectric materials for maximum conversion efficiency. It was also found that the absorber bandwidth is a theoretical limitation on radiant-electric conversion efficiency. Ideally, the absorbers' wavelength would be centered on the irradiating spectrum and have the same bandwith as the irradiating wave. The EWEC concept appears to have a valid scientific basis, but considerable more research is needed before it is thoroughly understood, especially for the complex randomly polarized, wide band, phase incoherent spectrum of the sun. Specific recommended research areas are identified.
Electromagnetic wave in a relativistic magnetized plasma
International Nuclear Information System (INIS)
Krasovitskiy, V. B.
2009-01-01
Results are presented from a theoretical investigation of the dispersion properties of a relativistic plasma in which an electromagnetic wave propagates along an external magnetic field. The dielectric tensor in integral form is simplified by separating its imaginary and real parts. A dispersion relation for an electromagnetic wave is obtained that makes it possible to analyze the dispersion and collisionless damping of electromagnetic perturbations over a broad parameter range for both nonrelativistic and ultrarelativistic plasmas.
International Nuclear Information System (INIS)
2009-01-01
The investigating committee aimed at research on electromagnetic fields in functional devices and X-ray fibers for efficient coherent X-ray generation and their material science, high-precision manufacturing, X-ray microscope, application to medical and information communication technologies, such as interaction between material and nanometer electromagnetic waves of radiated light and X-ray, interaction between microwaves and particle beams, theory and design of high-frequency waveguides for resonator and accelerator, from January 2003 to December 2005. In this report, we describe our research results, in particular, on the topics of synchrotron radiation and Cherenkov radiation, Kyushu synchrotron light source and its technology, nanometer electromagnetic fields in optical region, process of interaction between evanescent waves and near-field light, orthogonal relation of electromagnetic fields including evanescent waves in dispersive dielectrics, optical amplification using electron beam, nanometer electromagnetic fields in focusing waveguide lens device with curved facets, electromagnetic fields in nanometer photonic crystal waveguide consisting of atoms, X-ray scattering and absorption I bio-material for image diagnosis. (author)
Efficient transformer for electromagnetic waves
Miller, R.B.
A transformer structure for efficient transfer of electromagnetic energy from a transmission line to an unmatched load provides voltage multiplication and current division by a predetermined constant. Impedance levels are transformed by the square of that constant. The structure includes a wave splitter, connected to an input transmission device and to a plurality of output transmission devices. The output transmission devices are effectively connected in parallel to the input transmission device. The output transmission devices are effectively series connected to provide energy to a load. The transformer structure is particularly effective in increasing efficiency of energy transfer through an inverting convolute structure by capturing and transferring energy losses from the inverter to the load.
Interaction between electromagnetic waves and plasma waves in motional plasma
International Nuclear Information System (INIS)
Chen, S. Y.; Gao, M.; Tang, C. J.; Peng, X. D.
2009-01-01
The electromagnetic wave (EM wave) behavior and the electromagnetic instability caused by the interaction between an EM wave and a plasma wave in motional plasma are studied. The dispersion relation of EM waves and the dielectric tensor of motional plasma are derived by magnetohydrodynamics, and the wave phenomenon in motional plasma is displayed. As a result, the electromagnetic instability, which is excited by the interaction between the EM waves and the plasma waves, is revealed. The mechanism of the instability is the coupling between high frequency electromagnetic field and the transverse electron oscillation derived from the deflection of longitudinal electron oscillation due to self-magnetic field. The present research is useful with regard to the new type of plasma radiation source, ion-focusing accelerator, and plasma diagnostic technique.
At the heart of the waves - Electromagnetic fields in question
International Nuclear Information System (INIS)
Ndagijimana, Fabien; Gaudaire, Francois
2013-01-01
This document briefly presents a book in which the author describes what an electromagnetic wave is, the use of electromagnetic waves, how an information is transmitted by means of an electromagnetic wave, what wave modulation is, what multiplexing is, what the characteristics of an antenna are, how waves propagate, how electromagnetic shielding works, what the CEM (electromagnetic compatibility) is, and how a cellular phone network works, in the framework of electromagnetic fields risk assessment
Scattering theory of stochastic electromagnetic light waves.
Wang, Tao; Zhao, Daomu
2010-07-15
We generalize scattering theory to stochastic electromagnetic light waves. It is shown that when a stochastic electromagnetic light wave is scattered from a medium, the properties of the scattered field can be characterized by a 3 x 3 cross-spectral density matrix. An example of scattering of a spatially coherent electromagnetic light wave from a deterministic medium is discussed. Some interesting phenomena emerge, including the changes of the spectral degree of coherence and of the spectral degree of polarization of the scattered field.
Electromagnetic wave analogue of electronic diode
Shadrivov, Ilya V.; Powell, David A.; Kivshar, Yuri S.; Fedotov, Vassili A.; Zheludev, Nikolay I.
2010-01-01
An electronic diode is a nonlinear semiconductor circuit component that allows conduction of electrical current in one direction only. A component with similar functionality for electromagnetic waves, an electromagnetic isolator, is based on the Faraday effect of the polarization state rotation and is also a key component of optical and microwave systems. Here we demonstrate a chiral electromagnetic diode, which is a direct analogue of an electronic diode: its functionality is underpinned by ...
Coupled seismic and electromagnetic wave propagation
Schakel, M.D.
2011-01-01
Coupled seismic and electromagnetic wave propagation is studied theoretically and experimentally. This coupling arises because of the electrochemical double layer, which exists along the solid-grain/fluid-electrolyte boundaries of porous media. Within the double layer, charge is redistributed,
Scattering of electromagnetic waves by obstacles
Kristensson, Gerhard
2016-01-01
The main purpose of Scattering of Electromagnetic Waves by Obstacles is to give a theoretical treatment of the scattering phenomena, and to illustrate numerical computations of some canonical scattering problems for different geometries and materials.
Electromagnetic Vibration Energy Harvesting Devices Architectures, Design, Modeling and Optimization
Spreemann, Dirk
2012-01-01
Electromagnetic vibration transducers are seen as an effective way of harvesting ambient energy for the supply of sensor monitoring systems. Different electromagnetic coupling architectures have been employed but no comprehensive comparison with respect to their output performance has been carried out up to now. Electromagnetic Vibration Energy Harvesting Devices introduces an optimization approach which is applied to determine optimal dimensions of the components (magnet, coil and back iron). Eight different commonly applied coupling architectures are investigated. The results show that correct dimensions are of great significance for maximizing the efficiency of the energy conversion. A comparison yields the architectures with the best output performance capability which should be preferably employed in applications. A prototype development is used to demonstrate how the optimization calculations can be integrated into the design–flow. Electromagnetic Vibration Energy Harvesting Devices targets the design...
Propagation of SLF/ELF electromagnetic waves
Pan, Weiyan
2014-01-01
This book deals with the SLF/ELF wave propagation, an important branch of electromagnetic theory. The SLF/ELF wave propagation theory is well applied in earthquake electromagnetic radiation, submarine communication, thunderstorm detection, and geophysical prospecting and diagnostics. The propagation of SLF/ELF electromagnetic waves is introduced in various media like the earth-ionospheric waveguide, ionospheric plasma, sea water, earth, and the boundary between two different media or the stratified media. Applications in the earthquake electromagnetic radiation and the submarine communications are also addressed. This book is intended for scientists and engineers in the fields of radio propagation and EM theory and applications. Prof. Pan is a professor at China Research Institute of Radiowave Propagation in Qingdao (China). Dr. Li is a professor at Zhejiang University in Hangzhou (China).
Terrestrial propagation of long electromagnetic waves
Galejs, Janis; Fock, V A
2013-01-01
Terrestrial Propagation of Long Electromagnetic Waves deals with the propagation of long electromagnetic waves confined principally to the shell between the earth and the ionosphere, known as the terrestrial waveguide. The discussion is limited to steady-state solutions in a waveguide that is uniform in the direction of propagation. Wave propagation is characterized almost exclusively by mode theory. The mathematics are developed only for sources at the ground surface or within the waveguide, including artificial sources as well as lightning discharges. This volume is comprised of nine chapte
Current generation by monochromatic electromagnetic waves
International Nuclear Information System (INIS)
Belikov, V.S.; Kolesnichenko, Ya.I.; Plotnik, I.S.
1983-01-01
The generation of longitudinal currents in a magnetically confined plasma with travelling monochromatic electromagnetic waves of finite amplitude propagating at some angle to the external magnetic field is considered. By averaging over the particle cyclotron gyration period, the kinetic equation for the distribution function of electrons interacting with an electromagnetic wave is derived. This equation is solved for the case of low-frequency waves, on the assumption that the bounce period of electrons trapped by the wave field is small compared to the typical times of Coulomb collisions (in which case, the driving current is largest). From the solution obtained, analytic expressions for the driving current and the absorbed power, which are valid for a wide range of wave phase velocities, are found. The current drive method considered and the method using the wave packet are compared. (author)
Electromagnetic wave analogue of an electronic diode
International Nuclear Information System (INIS)
Shadrivov, Ilya V; Powell, David A; Kivshar, Yuri S; Fedotov, Vassili A; Zheludev, Nikolay I
2011-01-01
An electronic diode is a nonlinear semiconductor circuit component that allows conduction of electrical current in one direction only. A component with similar functionality for electromagnetic waves, an electromagnetic isolator, is based on the Faraday effect of rotation of the polarization state and is also a key component in optical and microwave systems. Here we demonstrate a chiral electromagnetic diode, which is a direct analogue of an electronic diode: its functionality is underpinned by an extraordinarily strong nonlinear wave propagation effect in the same way as the electronic diode function is provided by the nonlinear current characteristic of a semiconductor junction. The effect exploited in this new electromagnetic diode is an intensity-dependent polarization change in an artificial chiral metamolecule. This microwave effect exceeds a similar optical effect previously observed in natural crystals by more than 12 orders of magnitude and a direction-dependent transmission that differs by a factor of 65.
An electromagnetic inerter-based vibration suppression device
International Nuclear Information System (INIS)
Gonzalez-Buelga, A; Clare, L R; Neild, S A; Jiang, J Z; Inman, D J
2015-01-01
This paper describes how an inerter-based device for structural vibration suppression can be realized using an electromagnetic transducer such as a linear motor. When the motor shaft moves, a difference of voltage is generated across the transducer coil. The voltage difference is proportional to the relative velocity between its two terminals. The electromagnetic transducer will exert a force proportional to current following the Lorentz principle if the circuit is closed around the transducer coil. If an electronic circuit consisting of a capacitor, an inductance and a resistance with the appropriate configuration is connected, the resulting force reflected back into the mechanical domain is equivalent to that achieved by a mechanical inerter-based device. The proposed configuration is easy to implement and very versatile, provided a high quality conversion system with negligible losses. With the use of electromagnetic devices, a new generation of vibration absorbers can be realized, for example in the electrical domain it would be relatively uncomplicated to synthesize multi-frequency or real time tunable vibration absorbers by adding electrical components in parallel. In addition by using resistance emulators in the electrical circuits, part of the absorbed vibration energy can be converted into usable power. Here an electromagnetic tuned inerter damper (E-TID) is tested experimentally using real time dynamic substructuring. A voltage compensation unit was developed in order to compensate for coil losses. This voltage compensation unit requires power, which is acquired through harvesting from the vibration energy using a resistance emulator. A power balance analysis was developed in order to ensure the device can be self sufficient. Promising experimental results, using this approach, have been obtained and are presented in this paper. The ultimate goal of this research is the development of autonomous electromagnetic vibration absorbers, able to harvest energy
Use of electro-magnetic damping for vibration control
DEFF Research Database (Denmark)
Stein, George Juraj; Darula, Radoslav; Sorokin, Sergey
2012-01-01
to introduce additional electromagnetic damping into vibrating mechanical system. The hysteretic losses and eddy currents are included in the model, to take into account more realistic dynamic behaviour of the system. The mathematical model of the controller is derived using lumped parameter approach......Vibration of machines is an unwanted phenomenon, and it is usually of interest to eliminate it. There are various means to be used in order to reach the goal, where the utilization of the electromagnet augmented by an external shunt circuit is analyzed in the paper. The magnetic force is used...
Fundamentals of electromagnetics 2 quasistatics and waves
Voltmer, David
2007-01-01
This book is the second of two volumes which have been created to provide an understanding of the basic principles and applications of electromagnetic fields for electrical engineering students. Fundamentals of Electromagnetics Vol 2: Quasistatics and Waves examines how the low-frequency models of lumped elements are modified to include parasitic elements. For even higher frequencies, wave behavior in space and on transmission lines is explained. Finally, the textbook concludes with details of transmission line properties and applications. Upon completion of this book and its companion Fundame
Electromagnetic wave propagating along a space curve
Lai, Meng-Yun; Wang, Yong-Long; Liang, Guo-Hua; Wang, Fan; Zong, Hong-Shi
2018-03-01
By using the thin-layer approach, we derive the effective equation for the electromagnetic wave propagating along a space curve. We find intrinsic spin-orbit, extrinsic spin-orbit, and extrinsic orbital angular-momentum and intrinsic orbital angular-momentum couplings induced by torsion, which can lead to geometric phase, spin, and orbital Hall effects. And we show the helicity inversion induced by curvature that can convert a right-handed circularly polarized electromagnetic wave into a left-handed polarized one, vice versa. Finally, we demonstrate that the gauge invariance of the effective dynamics is protected by the geometrically induced gauge potential.
Excitation of blade vibration under rotation by synchronous electromagnet
Czech Academy of Sciences Publication Activity Database
Pešek, Luděk; Vaněk, František; Bula, Vítězslav; Cibulka, Jan
2011-01-01
Roč. 18, 3/4 (2011), s. 1-9 ISSN 1802-1484 R&D Projects: GA ČR GA101/09/1166 Institutional research plan: CEZ:AV0Z20760514 Keywords : blade * vibration * excitation * electromagnet Subject RIV: BI - Acoustics
Electromagnetic Wave Propagation in Random Media
DEFF Research Database (Denmark)
Pécseli, Hans
1984-01-01
The propagation of a narrow frequency band beam of electromagnetic waves in a medium with randomly varying index of refraction is considered. A novel formulation of the governing equation is proposed. An equation for the average Green function (or transition probability) can then be derived...
MMS Observations of Harmonic Electromagnetic Cyclotron Waves
Usanova, M.; Ahmadi, N.; Ergun, R.; Trattner, K. J.; Fuselier, S. A.; Torbert, R. B.; Mauk, B.; Le Contel, O.; Giles, B. L.; Russell, C. T.; Burch, J.; Strangeway, R. J.
2017-12-01
Harmonically related electromagnetic ion cyclotron waves with the fundamental frequency near the O+ cyclotron frequency were observed by the four MMS spacecraft on May 20, 2016. The wave activity was detected by the spacecraft on their inbound passage through the Earth's morning magnetosphere during generally quiet geomagnetic conditions but enhanced solar wind dynamic pressure. It was also associated with an enhancement of energetic H+ and O+ ions. The waves are seen in both magnetic and electric fields, formed by over ten higher order harmonics, most pronounced in the electric field. The wave activity lasted for about an hour with some wave packets giving rise to short-lived structures extending from Hz to kHz range. These observations are particularly interesting since they suggest cross-frequency coupling between the lower and higher frequency modes. Further work will focus on examining the nature and role of these waves in the energetic particle dynamics from a theoretical perspective.
Electromagnetic wave collapse in a radiation background
International Nuclear Information System (INIS)
Marklund, Mattias; Brodin, Gert; Stenflo, Lennart
2003-01-01
The nonlinear interaction, due to quantum electrodynamical (QED) effects between an electromagnetic pulse and a radiation background, is investigated by combining the methods of radiation hydrodynamics with the QED theory for photon-photon scattering. For the case of a single coherent electromagnetic pulse, we obtain a Zakharov-like system, where the radiation pressure of the pulse acts as a driver of acoustic waves in the photon gas. For a sufficiently intense pulse and/or background energy density, there is focusing and the subsequent collapse of the pulse. The relevance of our results for various astrophysical applications are discussed
Effect of electromagnetic waves on human reproduction.
Wdowiak, Artur; Mazurek, Paweł A; Wdowiak, Anita; Bojar, Iwona
2017-03-31
Electromagnetic radiation (EMR) emitting from the natural environment, as well as from the use of industrial and everyday appliances, constantly influence the human body. The effect of this type of energy on living tissues may exert various effects on their functioning, although the mechanisms conditioning this phenomenon have not been fully explained. It may be expected that the interactions between electromagnetic radiation and the living organism would depend on the amount and parameters of the transmitted energy and type of tissue exposed. Electromagnetic waves exert an influence on human reproduction by affecting the male and female reproductive systems, the developing embryo, and subsequently, the foetus. Knowledge concerning this problem is still being expanded; however, all the conditionings of human reproduction still remain unknown. The study presents the current state of knowledge concerning the problem, based on the latest scientific reports.
Electromagnetic Wave Attenuation in Atmospheric Pressure Plasma
International Nuclear Information System (INIS)
Zhang Shu; Hu Xiwei; Liu Minghai; Luo Fang; Feng Zelong
2007-01-01
When an electromagnetic (EM) wave propagates in an atmospheric pressure plasma (APP) layer, its attenuation depends on the APP parameters such as the layer width, the electron density and its profile and collision frequency between electrons and neutrals. This paper proposes that a combined parameter-the product of the line average electron density n-bar and width d of the APP layer (i.e., the total number of electrons in a unit volume along the wave propagation path) can play a more explicit and decisive role in the wave attenuation than any of the above individual parameters does. The attenuation of the EM wave via the product of n-bar and d with various collision frequencies between electrons and neutrals is presented
Vibration control of a flexible structure with electromagnetic actuators
DEFF Research Database (Denmark)
Gruzman, Maurício; Santos, Ilmar
2016-01-01
This work presents the model of a shear-frame-type structure composed of six flexible beams and three rigid masses. Fixed on the ground, outside the structure, two voltage-controlled electromagnetic actuators are used for vibration control. To model the flexible beams, unidimensional finite...... elements were used. Nonlinear equations for the actuator electromagnetic force, noise in the position sensor, time delays for the control signal update and voltage saturation were also considered in the model. For controlling purposes, a discrete linear quadratic regulator combined with a predictive full......-order discrete linear observer was employed. Results of numerical simulations, where the structure is submitted to an impulsive disturbance force and to a harmonic force, show that the oscillations can be significantly reduced with the use of the electromagnetic actuators....
The solitary electromagnetic waves in the graphene superlattice
International Nuclear Information System (INIS)
Kryuchkov, Sergey V.; Kukhar', Egor I.
2013-01-01
d’Alembert equation written for the electromagnetic waves propagating in the graphene superlattice is analyzed. The possibility of the propagation of the solitary electromagnetic waves in the graphene superlattice is discussed. The amplitude and the width of the electromagnetic pulse are calculated. The drag current induced by such wave across the superlattice axis is investigated. The numerical estimate of the charge dragged by the solitary wave is made.
Electromagnetic harvester for lateral vibration in rotating machines
de Araujo, Marcus Vinícius Vitoratti; Nicoletti, Rodrigo
2015-02-01
Energy harvesters are devices that convert mechanical energy, usually vibration, into electrical energy that can be used to supply low power circuits (e.g. sensors). In this work, an energy harvester is designed for converting the mechanical energy of the lateral vibrations of shafts into electrical energy. For that, permanent magnets are mounted in the shaft and coils are mounted in a fixed structure. A configuration analysis is performed to find the appropriated polarization of the magnets and orientation of the coils in order to have electromagnetic induction without resisting torque on the shaft. Experimental tests are done for different electrical configurations of the coils: independent, in series and, in parallel. The results show that more electric power is induced when the coils are connected in series, and vibration reduction is more evident when the coils are connected independently.
Teaching Electromagnetic Waves in College Physics Laboratory
Kezerashvili, Roman Y.; Leng, L.
2006-12-01
One of the important educational advantages of the simultaneous study of the electromagnetic waves and light is to show that light and the electromagnetic radiation have the same properties so that the students can visualize the properties of the electromagnetic radiation through observation of light propagation. In our approach we are suggest to study the properties of a microwave radiation and light in parallel. The following experiments can be easily designed and they provide a methodical introduction to electromagnetic theory using the microwave radiation and light: the study of the inverse square law of the dependence of the intensity of radiation (microwave and light) on the distance, the law of reflection and refraction, investigation of the phenomenon of polarization and how a polarizer can be used to alter the polarization of microwave radiation and light, measuring the Brewster's angle, studying interference by performing double-slit experiment for microwave radiation and light. Finally students measure the wavelength of the laser light and microwave radiation using the corresponding versions the Michelson’s interferometer, and recognize that these two radiations only differ by the wavelength or frequency.
Parametric excitation of electromagnetic waves by electron Bernstein waves
International Nuclear Information System (INIS)
Kuo, S.P.
1992-01-01
A parametric instability involving the decay of a standing electron Bernstein pump into electromagnetic sidebands and lower-hybrid decay waves is studied. A general dispersion relation is derived and analyzed. Threshold fields and growth rates are obtained for the two cases that the electron Bernstein pump is introduced near the X-mode cutoff layer or introduced in the region between the upper-hybrid resonance layer and the O-mode cutoff layer. Applications of these results to the recent observation [P. Stubbe and H. Kopka, Phys. Rev. Lett. 65, 183 (1990)] of stimulated electromagnetic emission (SEE) with a broad symmetrical structure (BSS) in the ionospheric modifications by powerful high-frequency (HF) wave are discussed
Studies on anti-tumor effect of electromagnetic waves
International Nuclear Information System (INIS)
Kadota, Ikuhito; Wakabayashi, Toshio; Ogoshi, Kyoji; Kamijo, Akemi
1995-01-01
Hyperthermia have treated cancer with thermal effect of electromagnetic waves for biological systems, but the expected effect is not shown. Also non-thermal effect of electromagnetic waves is out of consideration. If irradiation conditions of electromagnetic waves with non-thermal anti-tumor effect are obtained, we can expect newly spread in cancer therapy. We had in vivo experiments that electromagnetic waves were irradiated to mice. In some irradiation conditions, the non-thermal anti-tumor effect of electromagnetic waves showed. In order to specify the irradiation conditions, we had in vitro experiments. We found that activity ratio of tumor cells which was measured by MTT method depended on irradiation time and power of electromagnetic waves. These results are useful for the cancer therapy. (author)
International Nuclear Information System (INIS)
Tao Fuzhen; He Zhiqiang
1983-01-01
If the effect of gravitational wave on electromagnetic fields is used, and the gravitational wave is detected through the changes in electromagnetic fields, one can expect that the difficulty about the weakness of the signal of mechanical receiver can be avoided. Because of the effect of gravitational wave, the electromagnetic field emits energy, therefore, the energy which is detected will be higher than that by the mechanical receiver. The authors consider the Maxwell equations on the curved spacetime. They give solutions when the detecting fields are a free electromagnetic wave, standing wave and a constant field. (Auth.)
Metamaterials, from electromagnetic waves to water waves, bending waves and beyond
Dupont, G.
2015-08-04
We will review our recent work on metamaterials for different types of waves. Transposition of transform optics to water waves and bending waves on plates will be considered with potential applications of cloaking to water waves protection and anti-vibrating systems.
International Nuclear Information System (INIS)
Palenzuela, Carlos; Lehner, Luis; Yoshida, Shin
2010-01-01
In addition to producing loud gravitational waves, the dynamics of a binary black hole system could induce emission of electromagnetic radiation by affecting the behavior of plasmas and electromagnetic fields in their vicinity. We study how the electromagnetic fields are affected by a pair of orbiting black holes through the merger. In particular, we show how the binary's dynamics induce a variability in possible electromagnetically induced emissions as well as an enhancement of electromagnetic fields during the late-merge and merger epochs. These time dependent features will likely leave their imprint in processes generating detectable emissions and can be exploited in the detection of electromagnetic counterparts of gravitational waves.
Electromagnetic wave scattering by many small particles
International Nuclear Information System (INIS)
Ramm, A.G.
2007-01-01
Scattering of electromagnetic waves by many small particles of arbitrary shapes is reduced rigorously to solving linear algebraic system of equations bypassing the usual usage of integral equations. The matrix elements of this linear algebraic system have physical meaning. They are expressed in terms of the electric and magnetic polarizability tensors. Analytical formulas are given for calculation of these tensors with any desired accuracy for homogeneous bodies of arbitrary shapes. An idea to create a 'smart' material by embedding many small particles in a given region is formulated
Characteristic wave velocities in spherical electromagnetic cloaks
International Nuclear Information System (INIS)
Yaghjian, A D; Maci, S; Martini, E
2009-01-01
We investigate the characteristic wave velocities in spherical electromagnetic cloaks, namely, phase, ray, group and energy-transport velocities. After deriving explicit expressions for the phase and ray velocities (the latter defined as the phase velocity along the direction of the Poynting vector), special attention is given to the determination of group and energy-transport velocities, because a cursory application of conventional formulae for local group and energy-transport velocities can lead to a discrepancy between these velocities if the permittivity and permeability dyadics are not equal over a frequency range about the center frequency. In contrast, a general theorem can be proven from Maxwell's equations that the local group and energy-transport velocities are equal in linear, lossless, frequency dispersive, source-free bianisotropic material. This apparent paradox is explained by showing that the local fields of the spherical cloak uncouple into an E wave and an H wave, each with its own group and energy-transport velocities, and that the group and energy-transport velocities of either the E wave or the H wave are equal and thus satisfy the general theorem.
Local electromagnetic waves in layered superconductors
International Nuclear Information System (INIS)
Gvozdikov, V.M.; Vega-Monroy, R.
1999-01-01
A dispersion equation for electromagnetic waves localized on a defect layer of a layered superconductor is obtained in the frame of a model which neglects electron hopping between layers but assumes an arbitrary current-current response function within the layers. The defect layer differs from the rest of the layers by density and mass of charge carriers. It is shown that near the critical temperature in the London limit the local mode lies within the superconducting gap and has a wave vector threshold depending on the layered crystal and defect layer parameters. In the case of highly anisotropic layered superconductors, like Bi- or Tl-based high-T c cuprates, the local mode exists within a narrow range of positive variations of the mass and charge carriers. (author)
Statistical Characterization of Electromagnetic Wave Propagation in Mine Environments
Yucel, Abdulkadir C.; Liu, Yang; Bagci, Hakan; Michielssen, Eric
2013-01-01
A computational framework for statistically characterizing electromagnetic (EM) wave propagation through mine tunnels and galleries is presented. The framework combines a multi-element probabilistic collocation method with a full-wave fast Fourier
Electromagnetic waves in single- and multi-Josephson junctions
International Nuclear Information System (INIS)
Matsumoto, Hideki; Koyama, Tomio; Machida, Masahiko
2008-01-01
The terahertz wave emission from the intrinsic Josephson junctions is one of recent topics in high T c superconductors. We investigate, by numerical simulation, properties of the electromagnetic waves excited by a constant bias current in the single- and multi-Josephson junctions. Nonlinear equations of phase-differences are solved numerically by treating the effects of the outside electromagnetic fields as dynamical boundary conditions. It is shown that the emitted power of the electromagnetic wave can become large near certain retrapping points of the I-V characteristics. An instability of the inside phase oscillation is related to large amplitude of the oscillatory waves. In the single- (or homogeneous mutli-) Josephson junctions, electromagnetic oscillations can occur either in a form of standing waves (shorter junctions) or by formation of vortex-antivortex pairs (longer junctions). How these two effects affects the behavior of electromagnetic waves in the intrinsic Josephson junctions is discussed
Absorption of low-frequency electromagnetic waves by plasma in electromagnetic trap
International Nuclear Information System (INIS)
D'yakov, V.E.
1984-01-01
Absorption of electromagnetic waves in plasma of the electromagnetic trap is investigated. An integro-differential equation describing the behaviour of the electrical and magnetic fields of the wave is obtained. The wave has a component along the plasma inhomogeneity axis. Solution of this equation is found within the low frequency range corresponding to the anomalous skin-effect. The possibility of ion-acoustic waves excitation is demonstrated. Expressions are found for reflection, absorption and transformation coefficients
Electromagnetic wave scattering by aerial and ground radar objects
Sukharevsky, Oleg I
2014-01-01
Electromagnetic Wave Scattering by Aerial and Ground Radar Objects presents the theory, original calculation methods, and computational results of the scattering characteristics of different aerial and ground radar objects. This must-have book provides essential background for computing electromagnetic wave scattering in the presence of different kinds of irregularities, as well as Summarizes fundamental electromagnetic statements such as the Lorentz reciprocity theorem and the image principleContains integral field representations enabling the study of scattering from various layered structur
2D full wave simulation on electromagnetic wave propagation in toroidal plasma
International Nuclear Information System (INIS)
Hojo, Hitoshi; Uruta, Go; Nakayama, Kazunori; Mase, Atsushi
2002-01-01
Global full-wave simulation on electromagnetic wave propagation in toroidal plasma with an external magnetic field imaging a tokamak configuration is performed in two dimensions. The temporal behavior of an electromagnetic wave launched into plasma from a wave-guiding region is obtained. (author)
Electromagnetic solitary waves in magnetized plasmas
International Nuclear Information System (INIS)
Hazeltine, R.D.; Holm, D.D.; Morrison, P.J.
1985-03-01
A Hamiltonian formulation, in terms of noncanonical Poisson bracket, is presented for a nonlinear fluid system that includes reduced magnetohydrodynamics and the Hasegawa-Mima equation as limiting cases. The single-helicity and axisymmetric versions possess three nonlinear Casimir invariants, from which a generalized potential can be constructed. Variation of the generalized potential yields a description of exact nonlinear stationary states. The new equilibria, allowing for plasma flow as well as partial electron adiabaticity, are distinct from those found in conventional magnetohydrodynamic theory. They differ from electrostatic stationary states in containing plasma current and magnetic field excitation. One class of steady-state solutions is shown to provide a simple electromagnetic generalization of drift-solitary waves
International Nuclear Information System (INIS)
Spreemann, Dirk; Hoffmann, Daniel; Folkmer, Bernd; Manoli, Yiannos
2008-01-01
This paper presents a design and optimization strategy for resonant electromagnetic vibration energy harvesting devices. An analytic expression for the magnetic field of cylindrical permanent magnets is used to build up an electromagnetic subsystem model. This subsystem is used to find the optimal resting position of the oscillating mass and to optimize the geometrical parameters (shape and size) of the magnet and coil. The objective function to be investigated is thereby the maximum voltage output of the transducer. An additional mechanical subsystem model based on well-known equations describing the dynamics of spring–mass–damper systems is established to simulate both nonlinear spring characteristics and the effect of internal limit stops. The mechanical subsystem enables the identification of optimal spring characteristics for realistic operation conditions such as stochastic vibrations. With the overall transducer model, a combination of both subsystems connected to a simple electrical circuit, a virtual operation of the optimized vibration transducer excited by a measured random acceleration profile can be performed. It is shown that the optimization approach results in an appreciable increase of the converter performance
Electromagnetic waves in dusty magnetoplasmas using two-potential theory
International Nuclear Information System (INIS)
Zubia, K.; Jamil, M.; Salimullah, M.
2009-01-01
The low-frequency long wavelength electromagnetic waves, viz., shear Alfven waves in a cold dusty plasma, have been examined employing two-potential theory and plasma fluid model. The presence of the unmagnetized dust particles and magnetized plasma components gives rise to a new ion-dust lower hybrid cutoff frequency for the electromagnetic shear Alfven wave propagation. The importance and relevance of the present work to the space dusty plasma environments are also pointed out.
Width of electromagnetic wave instability spectrum in tungsten plate
International Nuclear Information System (INIS)
Rinkevich, A.B.
1995-01-01
Based on the study of high-frequency signal modulation and spectrum analysis of the envelope a measurement of spectrum width for electromagnetic wave instability was carried out under conditions of current pulse action on tungsten plate in magnetic field. The existence of amplitude-frequency wave modulation was revealed. The width of current disturbance spectrum in a specimen was evaluated. Current disturbances are shown to cause the instability of electromagnetic wave. 11 refs.; 6 figs
Scattering of electromagnetic waves into plasma oscillations via plasma particles
International Nuclear Information System (INIS)
Lin, A.T.; Dawson, J.M.
1975-01-01
A plasma subjected to an intense electromagnetic wave can exhibit a large number of parametric instabilities. An interesting example which has received little attention is the decay of the electromagnetic wave into a plasma oscillation with the excess energy and momentum being carried off by electrons. This process has been simulated on a one-and-two-halves dimensional electromagnetic code. The incident electromagnetic wave had a frequency near the plasma frequency so that decay into a plasma oscillation and a backscattered electromagnetic wave was excluded. As expected, the threshold for this instability was very large , so it is unlikely that this instability is competitive in most laser plasmas. Nevertheless, the physical mechanism involved provides a means for absorption of laser light and acceleration of particles in a plasma containing large amplitude plasma oscillations
Analyses of electromagnetic and piezoelectric systems for efficient vibration energy harvesting
Hadas, Z.; Smilek, J.; Rubes, O.
2017-05-01
The paper deals with analyses and evaluation of vibration energy harvesting systems which are based on electromagnetic and piezoelectric physical principles off electro-mechanical conversion. Energy harvesting systems are associated with wireless sensors and a monitoring of engineering objects. The most of engineering objects operate with unwanted mechanical vibrations. However, vibrations could provide an ambient source of energy which is converted into useful electricity. The use of electromagnetic and piezoelectric vibration energy harvesters is analyzed in this paper. Thee evaluated output power is used for a choice of the efficient system with respect to the character of vibrations and thee required power output.
Analytic descriptions of cylindrical electromagnetic waves in a nonlinear medium
Xiong, Hao; Si, Liu-Gang; Yang, Xiaoxue; Wu, Ying
2015-01-01
A simple but highly efficient approach for dealing with the problem of cylindrical electromagnetic waves propagation in a nonlinear medium is proposed based on an exact solution proposed recently. We derive an analytical explicit formula, which exhibiting rich interesting nonlinear effects, to describe the propagation of any amount of cylindrical electromagnetic waves in a nonlinear medium. The results obtained by using the present method are accurately concordant with the results of using traditional coupled-wave equations. As an example of application, we discuss how a third wave affects the sum- and difference-frequency generation of two waves propagation in the nonlinear medium. PMID:26073066
Do electromagnetic waves always propagate along null geodesics?
International Nuclear Information System (INIS)
Asenjo, Felipe A; Hojman, Sergio A
2017-01-01
We find exact solutions to Maxwell equations written in terms of four-vector potentials in non–rotating, as well as in Gödel and Kerr spacetimes. We show that Maxwell equations can be reduced to two uncoupled second-order differential equations for combinations of the components of the four-vector potential. Exact electromagnetic waves solutions are written on given gravitational field backgrounds where they evolve. We find that in non–rotating spherical symmetric spacetimes, electromagnetic waves travel along null geodesics. However, electromagnetic waves on Gödel and Kerr spacetimes do not exhibit that behavior. (paper)
Electromagnetic waves in optical fibres in a magnetic field
International Nuclear Information System (INIS)
Gorelik, V S; Burdanova, M G
2016-01-01
A new method is reported of recording the secondary radiation of luminescent substances based on the use of capillary fibres of great length. Theoretical analysis of the dispersion curves of electromagnetic radiation in capillary fibres doped with erbium ions Er 3+ has been established. The Lorentz model is used for describing the dispersion properties of electromagnetic waves in a homogeneous medium doped with rare-earth ions. The dispersion dependencies of polariton and axion–polariton waves in erbium nitrate hydrate are determined on the basis of the model of the interaction between electromagnetic waves and the resonance electronic states of erbium ions in the absence and presence of a magnetic field. (paper)
Development of S-wave portable vibrator; S ha potable vibrator shingen no kaihatsu
Energy Technology Data Exchange (ETDEWEB)
Kaida, Y; Matsubara, Y [OYO Corp., Tokyo (Japan); Nijhof, V; Brouwer, J
1996-05-01
An S-wave portable vibrator to serve as a seismic source has been developed for the purpose of applying the shallow-layer reflection method to the study of the soil ground. The author, et al., who previously developed a P-wave portable vibrator has now developed an S-wave version, considering the advantage of the S-wave over the P-wave in that, for example, the S-wave velocity may be directly compared with the N-value representing ground strength and that the S-wave travels more slowly than the P-wave through sticky soil promising a higher-resolution exploration. The experimentally constructed S-wave vibrator consists of a conventional P-wave vibrator and an L-type wooden base plate combined therewith. Serving as the monitor for vibration is a conventional accelerometer without any modification. The applicability test was carried out at a location where a plank hammering test was once conducted for reflection aided exploration, and the result was compared with that of the plank hammering test. As the result, it was found that after some preliminary treatment the results of the two tests were roughly the same but that both reflected waves were a little sharper in the S-wave vibrator test than in the plank hammering test. 4 refs., 9 figs., 1 tab.
Electromagnetic radiation accompanying gravitational waves from black hole binaries
Energy Technology Data Exchange (ETDEWEB)
Dolgov, A. [Dept. of Physics, Novosibirsk State University, Pirogova 2, 630090 Novosibirsk (Russian Federation); Postnov, K., E-mail: dolgov@fe.infn.it, E-mail: kpostnov@gmail.com [Sternberg Astronomical Institute, Moscow M.V. Lomonosov State University, Universitetskij pr. 13, 119234 Moscow (Russian Federation)
2017-09-01
The transition of powerful gravitational waves, created by the coalescence of massive black hole binaries, into electromagnetic radiation in external magnetic fields is considered. In contrast to the previous calculations of the similar effect we study the realistic case of the gravitational radiation frequency below the plasma frequency of the surrounding medium. The gravitational waves propagating in the plasma constantly create electromagnetic radiation dragging it with them, despite the low frequency. The plasma heating by the unattenuated electromagnetic wave may be significant in hot rarefied plasma with strong magnetic field and can lead to a noticeable burst of electromagnetic radiation with higher frequency. The graviton-to-photon conversion effect in plasma is discussed in the context of possible electromagnetic counterparts of GW150914 and GW170104.
Electromagnetic radiation accompanying gravitational waves from black hole binaries
International Nuclear Information System (INIS)
Dolgov, A.; Postnov, K.
2017-01-01
The transition of powerful gravitational waves, created by the coalescence of massive black hole binaries, into electromagnetic radiation in external magnetic fields is considered. In contrast to the previous calculations of the similar effect we study the realistic case of the gravitational radiation frequency below the plasma frequency of the surrounding medium. The gravitational waves propagating in the plasma constantly create electromagnetic radiation dragging it with them, despite the low frequency. The plasma heating by the unattenuated electromagnetic wave may be significant in hot rarefied plasma with strong magnetic field and can lead to a noticeable burst of electromagnetic radiation with higher frequency. The graviton-to-photon conversion effect in plasma is discussed in the context of possible electromagnetic counterparts of GW150914 and GW170104.
Small discussion of electromagnetic wave anomalies preceding earthquakes
Energy Technology Data Exchange (ETDEWEB)
1980-01-01
Six brief pieces on various aspects of electromagnetic wave anomalies are presented. They cover: earthquake electromagnetic emanations; the use of magnetic induction information for earthquake forecasting; electromagnetic pulse emissions as pre-earthquake indicators; the use of magnetic sensors to determine medium-wavelength field strength for earthquake prediction purposes; magnetic deviation indicators inside reinforced-concrete buildings; and a discussion of the general physical principles involved.
Electromagnetic drift waves dispersion for arbitrarily collisional plasmas
Energy Technology Data Exchange (ETDEWEB)
Lee, Wonjae, E-mail: wol023@ucsd.edu; Krasheninnikov, Sergei I., E-mail: skrash@mae.ucsd.edu [Department of Mechanical and Aerospace Engineering, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093 (United States); Angus, J. R. [Naval Research Laboratory, 4555 Overlook Avenue, Washington, DC 20375 (United States)
2015-07-15
The impacts of the electromagnetic effects on resistive and collisionless drift waves are studied. A local linear analysis on an electromagnetic drift-kinetic equation with Bhatnagar-Gross-Krook-like collision operator demonstrates that the model is valid for describing linear growth rates of drift wave instabilities in a wide range of plasma parameters showing convergence to reference models for limiting cases. The wave-particle interactions drive collisionless drift-Alfvén wave instability in low collisionality and high beta plasma regime. The Landau resonance effects not only excite collisionless drift wave modes but also suppress high frequency electron inertia modes observed from an electromagnetic fluid model in collisionless and low beta regime. Considering ion temperature effects, it is found that the impact of finite Larmor radius effects significantly reduces the growth rate of the drift-Alfvén wave instability with synergistic effects of high beta stabilization and Landau resonance.
Coupled elasto-electromagnetic waves in bounded piezoelectric structures
Energy Technology Data Exchange (ETDEWEB)
Darinskii, A N [Institute of Crystallography RAS, Leninskiy pr. 59, Moscow, 119333 (Russian Federation); Clezio, E Le [Universite Francois Rabelais de Tours, ENI Val de Loire, LUSSI, FRE CNRS 2448, rue de la Chocolaterie, BP3410, 41034 Blois (France); Feuillard, G [Universite Francois Rabelais de Tours, ENI Val de Loire, LUSSI, FRE CNRS 2448, rue de la Chocolaterie, BP3410, 41034 Blois (France)
2007-12-15
The work studies theoretically the effect of electromagnetic wave generation on the acoustic wave reflection/transmission in anisotropic materials possessing piezoelectric properties. We are concerned with quasi-normal incidence at angles {theta}{sub i} {>=} v{sub a}/v{sub el} {approx} 10{sup -3} to 10{sup -5}, where v{sub a} and v{sub el} are the typical velocities of the acoustic and electromagnetic waves. It is shown that electromagnetic and acoustic waves are able to interact strongly despite a huge difference in velocities so that the wave behavior of time-dependent electric fields can drastically change the coefficients of mode conversion. In particular, examples exist of the situations where the acoustic wave must be totally reflected but quasi-electrostatic calculations predict almost total transmission.
Electromagnetic Lead Screw for Potential Wave Energy Application
DEFF Research Database (Denmark)
Lu, Kaiyuan; Wu, Weimin
2014-01-01
This paper presents a new type electromagnetic lead screw (EMLS) intended for wave energy application. Similar to the mechanical lead screw, this electromagnetic version can transfer slow linear motion to high-rotational motion, offering gearing effects. Compared with the existing pure magnetic...
Electromagnetic aquametry electromagnetic wave interaction with water and moist substances
Kupfer, Klaus
2006-01-01
This book covers all aspects of Electromagnetic Aquametry. It summarizes the wide area of metrology and its applications in electromagnetic sensing of moist materials. The physical properties of water in various degrees of binding interacting with electromagnetic fields is presented by model systems. The book describes measurement methods and sensors in the frequency domain, TDR-techniques for environmental problems, methods and sensors for quality assessment of biological substances, and nuclear magnetic resonance techniques. Environmental sciences, as well as civil and geoengineering, fossil fuels, food and pharmaceutical science are the main fields of application. A very wide frequency sprectrum is used for dielectric measurement methods, but the microwave range is clearly dominant. Multiparameter methods as well as methods of principal components and artificial neural networks for density independent measurements are described.
Coherent states of an electron in a quantized electromagnetic wave
International Nuclear Information System (INIS)
Bagrov, V.G.; Bukhbinder, I.L.; Gitman, D.M.; Lavrov, P.M.
1977-01-01
Coherent states for interacting electrons and photons in a plane elecmagnetic wave are found. Trajectories of the electron and the characteristics of the electromagnetic field are investigated. Limiting transition to the given external field is studied
Manipulating electromagnetic waves with metamaterials: Concept and microwave realizations
International Nuclear Information System (INIS)
He Qiong; Xiao Shi-Yi; Li Xin; Song Zheng-Yong; Sun Wu-Jiong; Zhou Lei; Sun Shu-Lin
2014-01-01
Our recent efforts in manipulating electromagnetic (EM) waves using metamaterials (MTMs) are reviewed with emphasis on 1) manipulating wave polarization and transporting properties using homogeneous MTMs, 2) manipulating surface-wave properties using plasmonic MTMs, and 3) bridging propagating and surface waves using inhomogeneous meta-surfaces. For all these topics, we first illustrate the physical concepts and then present several typical practical realizations and applications in the microwave regime. (topical review - plasmonics and metamaterials)
Parametric trapping of electromagnetic waves in an inhomogeneous plasma
International Nuclear Information System (INIS)
Silin, V.P.; Starodub, A.N.
1977-01-01
Considered is parametric instability in an inhomogeneous plasma at which a pumping wave is transformed to an electromagnetic wave and aperiodically in-time-growing disturbances. It is shown that after achievement of some boundary pumping value by electric field intensity an absolute parametric instability evolution becomes possible. In-time growing plasma disturbances are localized near electric field extremums of a pumping wave. Such localization areas are small as compared to characteristic size of pumping inhomogeneity in a plasma. The secondary electromagnetic waves stay within the localization areas and, therefore, are not scattered by a plasma. As following from this it has been established, that due to parametric instability electromagnetic radiation trapping by a plasma occurs. Such a trapping is considerably connected with a spatial structure of a pumping field and it cannot arise within the field of a running wave in the theoretical model considered. However parametric trapping turns out to be possible even with very small reflection coefficients
The electromagnetic interferent antennae for gravitational waves detection
International Nuclear Information System (INIS)
Kulak, A.
1984-01-01
An electromagnetic wave propagating in the toroidal waveguide is considered as an electromagnetic gravitational antenna. An interferometric method is applied to measure the disturbances of phase of the electromagnetic field caused by the incident gravitational wave. The calculations presented take into account the dispersive and dissipative phenomena occurring during the interaction between electromagnetic and gravitational fields. The active cross-section of the antenna interacting with coherent and pulsed gravitational radiation is estimated. Experimental possibilities presently available are discussed. Limiting fluxes in the astrophysical range of frequencies measured by the interferometric electromagnetic antenna are a factor of ten or so smaller than in the case of a classic mechanical antenna. Moreover the antenna could be used for carrying out a gravitational Hertz experiment. (author)
Planar passive electromagnetic deflector for millimeter-wave frequencies
Kastelijn, M.C.T.; Akkermans, J.A.G.
2008-01-01
A novel passive planar structure is proposed that is able to deflect an incoming electromagnetic (EM) wave into a desired direction. The direction of the outgoing EM wave is determined by the design of this deflector. The deflector can be used to extend coverage of a steerable source with limited
On scattering of electromagnetic waves by a wormhole
International Nuclear Information System (INIS)
Kirillov, A.A.; Savelova, E.P.
2012-01-01
We consider scattering of a plane electromagnetic wave by a wormhole. It is found that the scattered wave is depolarized and has a specific interference picture depending on parameters of the wormhole and the distance to the observer. It is proposed that such features can be important in the direct search of wormholes.
On scattering of electromagnetic waves by a wormhole
Energy Technology Data Exchange (ETDEWEB)
Kirillov, A.A., E-mail: ka98@mail.ru [Dubna International University of Nature, Society and Man, Universitetskaya Str. 19, Dubna, 141980 (Russian Federation); Savelova, E.P. [Dubna International University of Nature, Society and Man, Universitetskaya Str. 19, Dubna, 141980 (Russian Federation)
2012-04-20
We consider scattering of a plane electromagnetic wave by a wormhole. It is found that the scattered wave is depolarized and has a specific interference picture depending on parameters of the wormhole and the distance to the observer. It is proposed that such features can be important in the direct search of wormholes.
Statistical Characterization of Electromagnetic Wave Propagation in Mine Environments
Yucel, Abdulkadir C.
2013-01-01
A computational framework for statistically characterizing electromagnetic (EM) wave propagation through mine tunnels and galleries is presented. The framework combines a multi-element probabilistic collocation method with a full-wave fast Fourier transform and fast multipole method accelerated surface integral equation-based EM simulator to statistically characterize fields from wireless transmitters in complex mine environments. 1536-1225 © 2013 IEEE.
An Apparatus for Constructing an Electromagnetic Plane Wave Model
Kneubil, Fabiana Botelho; Loures, Marcus Vinicius Russo; Amado, William
2015-01-01
In this paper we report on an activity aimed at building an electromagnetic wave. This was part of a class on the concept of mass offered to a group of 20 pre-service Brazilian physics teachers. The activity consisted of building a plane wave using an apparatus in which it is possible to fit some rods representing electric and magnetic fields into…
On new electromagnetic waves in a multicomponent insulator
Dubovik, V. M.
The dispersion equation for additional transverse electromagnetic waves in a multicomponent amorphous insulator is analyzed in the vicinity of a narrow absorption line. Such waves can be excited due to spatial dispersion associated with fluctuation of the polarizability of insulator molecules. The
Resonant emission of electromagnetic waves by plasma solitons
International Nuclear Information System (INIS)
Mironov, V.A.; Sergeev, A.M.; Khimich, A.V.
1988-01-01
The ability of plasma-wave solitons to radiate electromagnetic waves at the frequency of the natural oscillations of the field is considered. It is shown that this radiation is the main energy dissipation channel for strong plasma turbulence in a magnetoactive plasma. An interpretation is proposed for the artificial radio emission produced when the ionosphere is acted upon by beams of strong electromagnetic waves. The use of this phenomenon for plasma turbulence, particularly in the outer-space plasma near the earth, is discussed
Transition operators in electromagnetic-wave diffraction theory - General theory
Hahne, G. E.
1992-01-01
A formal theory is developed for the scattering of time-harmonic electromagnetic waves from impenetrable immobile obstacles with given linear, homogeneous, and generally nonlocal boundary conditions of Leontovich (impedance) type for the wave of the obstacle's surface. The theory is modeled on the complete Green's function and the transition (T) operator in time-independent formal scattering theory of nonrelativistic quantum mechanics. An expression for the differential scattering cross section for plane electromagnetic waves is derived in terms of certain matrix elements of the T operator for the obstacle.
Second harmonic electromagnetic emission via Langmuir wave coalescence
International Nuclear Information System (INIS)
Willes, A.J.; Robinson, P.A.; Melrose, D.B.
1996-01-01
The coalescence of Langmuir waves to produce electromagnetic waves at twice the plasma frequency is considered. A simplified expression for the rate of production of second harmonic electromagnetic waves is obtained for a broad class of Langmuir spectra. In addition, two different analytic approximations are considered. The validity of the commonly used head-on approximation is explored, in which the two coalescing Langmuir waves are assumed to approach from opposite directions. This approximation breaks down at low Langmuir wavenumbers, and for narrow Langmuir wave spectra. A second, more general, approximation is introduced, called the narrow-spectrum approximation, which requires narrow spectral widths of the Langmuir spectra. The advantages of this approximation are that it does not break down at low Langmuir wavenumbers, and that it remains valid for relatively broad Langmuir wave spectra. Finally, the applicability of these approximations in treating harmonic radiation in type III solar radio bursts is discussed. copyright 1996 American Institute of Physics
Relativistic electromagnetic waves in an electron-ion plasma
Chian, Abraham C.-L.; Kennel, Charles F.
1987-01-01
High power laser beams can drive plasma particles to relativistic energies. An accurate description of strong waves requires the inclusion of ion dynamics in the analysis. The equations governing the propagation of relativistic electromagnetic waves in a cold electron-ion plasma can be reduced to two equations expressing conservation of energy-momentum of the system. The two conservation constants are functions of the plasma stream velocity, the wave velocity, the wave amplitude, and the electron-ion mass ratio. The dynamic parameter, expressing electron-ion momentum conversation in the laboratory frame, can be regarded as an adjustable quantity, a suitable choice of which will yield self-consistent solutions when other plasma parameters were specified. Circularly polarized electromagnetic waves and electrostatic plasma waves are used as illustrations.
Capture of charged particles by transverse electromagnetic waves
Energy Technology Data Exchange (ETDEWEB)
Davydovskii, V Ya; Sapogin, V G; Ukolov, A S
1975-01-01
An estimate is made of the maximum possible number of resonance particles interacting with a plane, transverse electromagnetic wave. The estimate is obtained by means of a distribution function, which is expressed in terms of the integrals of motion of the particles in the wave. Values of proton fluxes accelerated by an amplitude-modulated wave in the solar corona coincide with those observed during bursts of sporadic radioemission. (SJR)
Metamaterial Absorber for Electromagnetic Waves in Periodic Water Droplets.
Yoo, Young Joon; Ju, Sanghyun; Park, Sang Yoon; Ju Kim, Young; Bong, Jihye; Lim, Taekyung; Kim, Ki Won; Rhee, Joo Yull; Lee, YoungPak
2015-09-10
Perfect metamaterial absorber (PMA) can intercept electromagnetic wave harmful for body in Wi-Fi, cell phones and home appliances that we are daily using and provide stealth function that military fighter, tank and warship can avoid radar detection. We reported new concept of water droplet-based PMA absorbing perfectly electromagnetic wave with water, an eco-friendly material which is very plentiful on the earth. If arranging water droplets with particular height and diameter on material surface through the wettability of material surface, meta-properties absorbing electromagnetic wave perfectly in GHz wide-band were shown. It was possible to control absorption ratio and absorption wavelength band of electromagnetic wave according to the shape of water droplet-height and diameter- and apply to various flexible and/or transparent substrates such as plastic, glass and paper. In addition, this research examined how electromagnetic wave can be well absorbed in water droplets with low electrical conductivity unlike metal-based metamaterials inquiring highly electrical conductivity. Those results are judged to lead broad applications to variously civilian and military products in the future by providing perfect absorber of broadband in all products including transparent and bendable materials.
Effect of electromagnetic vibration on the microstructure of direct chill cast Al-Zn-Mg-Cu alloy
International Nuclear Information System (INIS)
Zuo, Y; Fu, X; Zhu, Q; Li, L; Wang, P; Cui, J
2016-01-01
An electromagnetic vibration was achieved by the combined application of an alternating magnetic field and a stationary magnetic field during direct chill (DC) casting process. The ingots with 200 mm in diameter were prepared under the influence of electromagnetic vibration. The effect of electromagnetic vibration on the microstructure of an Al-Zn-Mg-Cu alloy was studied. The results showed that electromagnetic vibration has a significant effect on the solidification behaviour, under the influence of electromagnetic vibration during DC casting process, the microstructure is significantly refined and the uniformity of microstructure is evidently improved. This paper introduces the DC casting technology with the application of electromagnetic vibration, presents these results and gives corresponding discussions. (paper)
[Mechanisms of primary reception of electromagnetic waves of optical range].
Huliar, S O; Lymans'kyĭ, Iu P
2003-01-01
An existence of separate functional system of regulation of electromagnetic balance of organism has been substantiated and a working conception of light therapy has been formulated. As a basis, there is a possibility to use the acupuncture points for input of biologically necessary electromagnetic waves into the system of their conductors in a body that might be considered as a transport facility for energy of the polarized electromagnetic waves. Zones-recipients are organs having an electromagnetic disbalance due to excess of biologically inadequate radiation and being the targets for peroxide oxidation. Foremost, a body has the neurohormonal and immune regulatory systems. Electromagnetic stimulation or modification of functions of the zones-recipients determines the achievement of therapeutic and useful effects, and their combination with local reparative processes allows to attain a clinical goal. We represent own and literary experimental data about the development of physiological responses (analgesia) to BIOPTRON-light exposure on the acupuncture points or biologically active zones. We show the experimental facts in support of a hypothesis that a living organism can perceive an action of the electromagnetic fields of optical range not only via the visual system, but also through the off-nerve receptors (specific energy-sensitive proteins detecting critical changes of energy in cells and functioning as the "sensory" cell systems), as well as via the acupuncture points. It confirms an important role of the electromagnetic waves of optical range in providing normal vital functions of living organisms. A current approach to BIOPTRON light therapy (by polarized polychromatic coherent low energy light) consists in combined (local and system) exposure of the electromagnetic waves within the biologically necessary range.
Electromagnetic forces and torques in nanoparticles irradiated by plane waves
International Nuclear Information System (INIS)
Garcia de Abajo, F.J.
2004-01-01
Optical tweezers and optical lattices are making it possible to control small particles by means of electromagnetic forces and torques. In this context, a method is presented in this work to calculate electromagnetic forces and torques for arbitrarily-shaped objects in the presence of other objects illuminated by a plane wave. The method is based upon an expansion of the electromagnetic field in terms of multipoles around each object, which are in turn used to derive forces and torques analytically. The calculation of multipole coefficients are obtained numerically by means of the boundary element method. Results are presented for both spherical and non-spherical objects
Electromagnetic Wave Chaos in Gradient Refractive Index Optical Cavities
International Nuclear Information System (INIS)
Wilkinson, P. B.; Fromhold, T. M.; Taylor, R. P.; Micolich, A. P.
2001-01-01
Electromagnetic wave chaos is investigated using two-dimensional optical cavities formed in a cylindrical gradient refractive index lens with reflective surfaces. When the planar ends of the lens are cut at an angle to its axis, the geometrical ray paths are chaotic. In this regime, the electromagnetic mode spectrum of the cavity is modulated by both real and ghost periodic ray paths, which also 'scar' the electric field intensity distributions of many modes. When the cavity is coupled to waveguides, the eigenmodes generate complex series of resonant peaks in the electromagnetic transmission spectrum
Manipulating the loss in electromagnetic cloaks for perfect wave absorption.
Argyropoulos, Christos; Kallos, Efthymios; Zhao, Yan; Hao, Yang
2009-05-11
We examine several ways to manipulate the loss in electro-magnetic cloaks, based on transformation electromagnetics. It is found that, by utilizing inherent electric and magnetic losses of metamaterials, perfect wave absorption can be achieved based on several popular designs of electromagnetic cloaks. A practical implementation of the absorber, consisting of ten discrete layers of metamaterials, is proposed. The new devices demonstrate super-absorptivity over a moderate wideband range, suitable for both microwave and optical applications. It is corroborated that the device is functional with a subwavelength thickness and, hence, advantageous compared to the conventional absorbers.
A metasurface carpet cloak for electromagnetic, acoustic and water waves.
Yang, Yihao; Wang, Huaping; Yu, Faxin; Xu, Zhiwei; Chen, Hongsheng
2016-01-29
We propose a single low-profile skin metasurface carpet cloak to hide objects with arbitrary shape and size under three different waves, i.e., electromagnetic (EM) waves, acoustic waves and water waves. We first present a metasurface which can control the local reflection phase of these three waves. By taking advantage of this metasurface, we then design a metasurface carpet cloak which provides an additional phase to compensate the phase distortion introduced by a bump, thus restoring the reflection waves as if the incident waves impinge onto a flat mirror. The finite element simulation results demonstrate that an object can be hidden under these three kinds of waves with a single metasurface cloak.
Electromagnetic internal gravity waves in the Earth's ionospheric E-layer
International Nuclear Information System (INIS)
Kaladze, T.D.; Tsamalashvili, L.V.; Kaladze, D.T.
2011-01-01
In the Earth's ionospheric E-layer existence of the new waves connecting with the electromagnetic nature of internal gravity waves is shown. They represent the mixture of the ordinary internal gravity waves and the new type of dispersive Alfven waves. -- Highlights: ► Existence of electromagnetic internal gravity waves in the ionospheric E-layer is shown. ► Electromagnetic nature of internal gravity waves is described. ► Appearance of the new dispersive Alfven waves is shown.
Electromagnetic resonance waves. Resonancias de ondas electromagneticas
Energy Technology Data Exchange (ETDEWEB)
Villaba, J.M.; Manjon, F.J.; Guirao, A.; Andres, M.V.
1994-01-01
We describe in this paper a set of experiments designed to make qualitative and quantitative measurements on electromagnetic resonances of several simple systems. The experiments are designed for the undergraduate laboratory of Electricity and Magnetism in Physics. These experiments can help the students understanding the concept of resonance, which appears in different fields of Physics. (Author) 8 refs.
Cell therapy for spinal cord injury informed by electromagnetic waves.
Finnegan, Jack; Ye, Hui
2016-10-01
Spinal cord injury devastates the CNS, besetting patients with symptoms including but not limited to: paralysis, autonomic nervous dysfunction, pain disorders and depression. Despite the identification of several molecular and genetic factors, a reliable regenerative therapy has yet to be produced for this terminal disease. Perhaps the missing piece of this puzzle will be discovered within endogenous electrotactic cellular behaviors. Neurons and stem cells both show mediated responses (growth rate, migration, differentiation) to electromagnetic waves, including direct current electric fields. This review analyzes the pathophysiology of spinal cord injury, the rationale for regenerative cell therapy and the evidence for directing cell therapy via electromagnetic waves shown by in vitro experiments.
Energy Technology Data Exchange (ETDEWEB)
Kalaee, Mohammad Javad, E-mail: mjkalaee@ut.ac.ir [Space Physics Group, Institute of Geophysics, University of Tehran (Iran, Islamic Republic of); Katoh, Yuto, E-mail: yuto@stpp.gp.tohoku.ac.jp [Department of Geophysics, Graduate School of Science, Tohoku University (Japan)
2016-07-15
One of the mechanisms for generating electromagnetic plasma waves (Z-mode and LO-mode) is mode conversion from electrostatic waves into electromagnetic waves in inhomogeneous plasma. Herein, we study a condition required for mode conversion of electrostatic waves propagating purely perpendicular to the ambient magnetic field, by numerically solving the full dispersion relation. An approximate model is derived describing the coupling between electrostatic waves (hot plasma Bernstein mode) and Z-mode waves at the upper hybrid frequency. The model is used to study conditions required for mode conversion from electrostatic waves (electrostatic electron cyclotron harmonic waves, including Bernstein mode) into electromagnetic plasma waves (LO-mode). It is shown that for mode conversion to occur in inhomogeneous plasma, the angle between the boundary surface and the magnetic field vector should be within a specific range. The range of the angle depends on the norm of the k vector of waves at the site of mode conversion in the inhomogeneous region. The present study reveals that inhomogeneity alone is not a sufficient condition for mode conversion from electrostatic waves to electromagnetic plasma waves and that the angle between the magnetic field and the density gradient plays an important role in the conversion process.
Self-reflection of intense electromagnetic waves in plasmas
Energy Technology Data Exchange (ETDEWEB)
Tewari, D P; Kumar, A; Sharma, J K [Indian Inst. of Tech., New Delhi. Dept. of Physics
1977-10-01
A uniform electromagnetic wave of high power density, propagating in a collisional plasma gives rise to a modification in temperature-dependent collision frequency and in turn induces a gradient in the complex refractive index of the medium. A WKB solution of the problem predicts a backward propagating wave on account of the self-induced inhomogeneity. The amplitude of the backward (i.e. reflected) wave increases with increasing power density of the wave. This is a volume nonlinear effect and is appreciable for usually employed power densities.
A new electromagnetic shunt damping treatment and vibration control of beam structures
International Nuclear Information System (INIS)
Niu Hongpan; Zhang Xinong; Xie Shilin; Wang Pengpeng
2009-01-01
In this paper a new class of shunted electromagnetic damping treatment is proposed: a non-contact electromagnetic shunt damper (NC-EMSD). The NC-EMSD consists of an electromagnet attached to a host structure, a permanent magnet attached to the fixed boundary and an electrical impedance connected to the terminals of the electromagnet. The electromagnet and the shunt impedance constitute a closed circuit. When the structure vibrates, an induced electromotive force will be produced and results in the electromagnetic force as damping force, which can suppress the vibration of the structure. The model of NC-EMSD is built up based on the equivalent current method. The governing equations of the beam with NC-EMSD are established using Hamilton's principle. The capacitor-matching-inductance (CMI) method and the negative resistive capacitor-matching-inductance (NR-CMI) method are proposed, respectively. Then the vibration control of a cantilever beam with NC-EMSD is simulated and measured by CMI and NR-CMI control methods, respectively. The results show that both the CMI and NR-CMI can attenuate the vibration effectively, and the NR-CMI provides much better control performance than that by CMI. It is indicated as well from the studies that the decrease of either the gap between the magnet pair or the resistance of the shunt impedance contributes to the improvement of control performance
Propagation of an ionizing surface electromagnetic wave
Energy Technology Data Exchange (ETDEWEB)
Boev, A.G.; Prokopov, A.V.
1976-11-01
The propagation of an rf surface wave in a plasma which is ionized by the wave itself is analyzed. The exact solution of the nonlinear Maxwell equations is discussed for the case in which the density of plasma electrons is an exponential function of the square of the electric field. The range over which the surface wave exists and the frequency dependence of the phase velocity are found. A detailed analysis is given for the case of a plasma whose initial density exceeds the critical density at the wave frequency. An increase in the wave amplitude is shown to expand the frequency range over which the plasma is transparent; The energy flux in the plasma tends toward a certain finite value which is governed by the effective ionization field.
International Nuclear Information System (INIS)
Braginsky, V.B.; Kardashev, N.S.; Polnarev, A.G.; Novikov, I.D.
1989-12-01
Propagation of an electromagnetic wave in the field of gravitational waves is considered. Attention is given to the principal difference between the electromagnetic wave propagation in the field of random gravitational waves and the electromagnetic wave propagation in a medium with a randomly-inhomogeneous refraction index. It is shown that in the case of the gravitation wave field the phase shift of an electromagnetic wave does not increase with distance. The capability of space radio interferometry to detect relic gravitational waves as well as gravitational wave bursts of non cosmological origin are analyzed. (author). 64 refs, 2 figs
On the polarization and depolarization of the electromagnetic waves
International Nuclear Information System (INIS)
Borghese, Ferdinando; Denti, Paolo; Saija, Rosalba; Cecchi-Pestellini, Cesare
2005-01-01
We discuss a general description of the polarization of monochromatic electromagnetic waves that proves useful when the customary description in terms of Stokes parameters does not apply. We also show how this description can be exploited to study the depolarization of linearly polarized waves in the interior of porous model cosmic dust grains. The results that we discuss may affect our understanding of several problems that are relevant for astrobiology
Response of thermal ions to electromagnetic ion cyclotron waves
Anderson, B. J.; Fuselier, S. A.
1994-01-01
Electromagnetic ion cyclotron waves generated by 10 - 50 keV protons in the Earth's equatorial magnetosphere will interact with the ambient low-energy ions also found in this region. We examine H(+) and He(+) distribution functions from approx. equals 1 to 160 eV using the Hot Plasma Composition Experiment instrument on AMPTE/CCE to investigate the thermal ion response to the waves. A total of 48 intervals were chosen on the basis of electromagnetic ion cyclotron (EMIC) wave activity: 24 with prevalent EMIC waves and 24 with no EMIC waves observed on the orbit. There is a close correlation between EMIC waves and perpendicular heated ion distributions. For protons the perpendicular temperature increase is modest, about 5 eV, and is always observed at 90 deg pitch angles. This is consistent with a nonresonant interaction near the equator. By contrast, He(+) temperatures during EMIC wave events averaged 35 eV and sometimes exceeded 100 eV, indicating stronger interaction with the waves. Furthermore, heated He(+) ions have X-type distributions with maximum fluxes occurring at pitch angles intermediate between field-aligned and perpendicular directions. The X-type He(+) distributions are consistent with a gyroresonant interaction off the equator. The concentration of He(+) relative to H(+) is found to correlate with EMIC wave activity, but it is suggested that the preferential heating of He(+) accounts for the apparent increase in relative He(+) concentration by increasing the proportion of He(+) detected by the ion instrument.
Molding acoustic, electromagnetic and water waves with a single cloak
Xu, Jun
2015-06-09
We describe two experiments demonstrating that a cylindrical cloak formerly introduced for linear surface liquid waves works equally well for sound and electromagnetic waves. This structured cloak behaves like an acoustic cloak with an effective anisotropic density and an electromagnetic cloak with an effective anisotropic permittivity, respectively. Measured forward scattering for pressure and magnetic fields are in good agreement and provide first evidence of broadband cloaking. Microwave experiments and 3D electromagnetic wave simulations further confirm reduced forward and backscattering when a rectangular metallic obstacle is surrounded by the structured cloak for cloaking frequencies between 2.6 and 7.0 GHz. This suggests, as supported by 2D finite element simulations, sound waves are cloaked between 3 and 8 KHz and linear surface liquid waves between 5 and 16 Hz. Moreover, microwave experiments show the field is reduced by 10 to 30 dB inside the invisibility region, which suggests the multi-wave cloak could be used as a protection against water, sonic or microwaves. © 2015, Nature Publishing Group. All rights reserved.
Molding acoustic, electromagnetic and water waves with a single cloak.
Xu, Jun; Jiang, Xu; Fang, Nicholas; Georget, Elodie; Abdeddaim, Redha; Geffrin, Jean-Michel; Farhat, Mohamed; Sabouroux, Pierre; Enoch, Stefan; Guenneau, Sébastien
2015-06-09
We describe two experiments demonstrating that a cylindrical cloak formerly introduced for linear surface liquid waves works equally well for sound and electromagnetic waves. This structured cloak behaves like an acoustic cloak with an effective anisotropic density and an electromagnetic cloak with an effective anisotropic permittivity, respectively. Measured forward scattering for pressure and magnetic fields are in good agreement and provide first evidence of broadband cloaking. Microwave experiments and 3D electromagnetic wave simulations further confirm reduced forward and backscattering when a rectangular metallic obstacle is surrounded by the structured cloak for cloaking frequencies between 2.6 and 7.0 GHz. This suggests, as supported by 2D finite element simulations, sound waves are cloaked between 3 and 8 KHz and linear surface liquid waves between 5 and 16 Hz. Moreover, microwave experiments show the field is reduced by 10 to 30 dB inside the invisibility region, which suggests the multi-wave cloak could be used as a protection against water, sonic or microwaves.
Molding acoustic, electromagnetic and water waves with a single cloak
Xu, Jun; Jiang, Xu; Fang, Nicholas; Georget, Elodie; Abdeddaim, Redha; Geffrin, Jean Michel; Farhat, Mohamed; Sabouroux, Pierre; Enoch, Stefan; Guenneau, Sé bastien
2015-01-01
We describe two experiments demonstrating that a cylindrical cloak formerly introduced for linear surface liquid waves works equally well for sound and electromagnetic waves. This structured cloak behaves like an acoustic cloak with an effective anisotropic density and an electromagnetic cloak with an effective anisotropic permittivity, respectively. Measured forward scattering for pressure and magnetic fields are in good agreement and provide first evidence of broadband cloaking. Microwave experiments and 3D electromagnetic wave simulations further confirm reduced forward and backscattering when a rectangular metallic obstacle is surrounded by the structured cloak for cloaking frequencies between 2.6 and 7.0 GHz. This suggests, as supported by 2D finite element simulations, sound waves are cloaked between 3 and 8 KHz and linear surface liquid waves between 5 and 16 Hz. Moreover, microwave experiments show the field is reduced by 10 to 30 dB inside the invisibility region, which suggests the multi-wave cloak could be used as a protection against water, sonic or microwaves. © 2015, Nature Publishing Group. All rights reserved.
Design of a bounded wave EMP (Electromagnetic Pulse) simulator
Sevat, P. A. A.
1989-06-01
Electromagnetic Pulse (EMP) simulators are used to simulate the EMP generated by a nuclear weapon and to harden equipment against the effects of EMP. At present, DREO has a 1 m EMP simulator for testing computer terminal size equipment. To develop the R and D capability for testing larger objects, such as a helicopter, a much bigger threat level facility is required. This report concerns the design of a bounded wave EMP simulator suitable for testing large size equipment. Different types of simulators are described and their pros and cons are discussed. A bounded wave parallel plate type simulator is chosen for it's efficiency and the least environmental impact. Detailed designs are given for 6 m and 10 m parallel plate type wire grid simulators. Electromagnetic fields inside and outside the simulators are computed. Preliminary specifications for a pulse generator required for the simulator are also given. Finally, the electromagnetic fields radiated from the simulator are computed and discussed.
INTEGRAL results on the electromagnetic counterparts of gravitational waves
DEFF Research Database (Denmark)
Mereghetti, S.; Savchenko, V.; Ferrigno, C.
2018-01-01
Thanks to its high orbit and a set of complementary detectors providing continuous coverage of the whole sky, the INTEGRAL satellite has unique capabilities for the identification and study of the electromagnetic radiation associated to gravitational waves signals and, more generally, for multi...
THE SIMULATION OF SCATTERING OF ELECTROMAGNETIC WAVES ON ANGULAR STRUCTURES.
Directory of Open Access Journals (Sweden)
P. A. Preobrazhensky
2017-02-01
Full Text Available The paper discusses the characteristics of scattering of electromagnetic waves on the angular diffraction structures. The solution of the problem is based on the method of integral equations. A comparative analysis of the scattering characteristics of structures with different shape is carried out.
FDTD Modelling of Electromagnetic waves in Stratified Medium ...
African Journals Online (AJOL)
The technique is an adaptation of the finite-difference time domain (FDTD) approach usually applied to model electromagnetic wave propagation. In this paper a simple 2D implementation of FDTD algorithm in mathematica environment is presented. Source implementation and the effect of conductivity on the incident field ...
Making structured metals transparent for ultrabroadband electromagnetic waves and acoustic waves
International Nuclear Information System (INIS)
Fan, Ren-Hao; Peng, Ru-Wen; Huang, Xian-Rong; Wang, Mu
2015-01-01
In this review, we present our recent work on making structured metals transparent for broadband electromagnetic waves and acoustic waves via excitation of surface waves. First, we theoretically show that one-dimensional metallic gratings can become transparent and completely antireflective for extremely broadband electromagnetic waves by relying on surface plasmons or spoof surface plasmons. Second, we experimentally demonstrate that metallic gratings with narrow slits are highly transparent for broadband terahertz waves at oblique incidence and high transmission efficiency is insensitive to the metal thickness. Further, we significantly develop oblique metal gratings transparent for broadband electromagnetic waves (including optical waves and terahertz ones) under normal incidence. In the third, we find the principles of broadband transparency for structured metals can be extended from one-dimensional metallic gratings to two-dimensional cases. Moreover, similar phenomena are found in sonic artificially metallic structures, which present the transparency for broadband acoustic waves. These investigations provide guidelines to develop many novel materials and devices, such as transparent conducting panels, antireflective solar cells, and other broadband metamaterials and stealth technologies. - Highlights: • Making structured metals transparent for ultrabroadband electromagnetic waves. • Non-resonant excitation of surface plasmons or spoof surface plasmons. • Sonic artificially metallic structures transparent for broadband acoustic waves
Making structured metals transparent for ultrabroadband electromagnetic waves and acoustic waves
Energy Technology Data Exchange (ETDEWEB)
Fan, Ren-Hao [National Laboratory of Solid State Microstructures and School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093 (China); Peng, Ru-Wen, E-mail: rwpeng@nju.edu.cn [National Laboratory of Solid State Microstructures and School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093 (China); Huang, Xian-Rong [Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439 (United States); Wang, Mu [National Laboratory of Solid State Microstructures and School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093 (China)
2015-07-15
In this review, we present our recent work on making structured metals transparent for broadband electromagnetic waves and acoustic waves via excitation of surface waves. First, we theoretically show that one-dimensional metallic gratings can become transparent and completely antireflective for extremely broadband electromagnetic waves by relying on surface plasmons or spoof surface plasmons. Second, we experimentally demonstrate that metallic gratings with narrow slits are highly transparent for broadband terahertz waves at oblique incidence and high transmission efficiency is insensitive to the metal thickness. Further, we significantly develop oblique metal gratings transparent for broadband electromagnetic waves (including optical waves and terahertz ones) under normal incidence. In the third, we find the principles of broadband transparency for structured metals can be extended from one-dimensional metallic gratings to two-dimensional cases. Moreover, similar phenomena are found in sonic artificially metallic structures, which present the transparency for broadband acoustic waves. These investigations provide guidelines to develop many novel materials and devices, such as transparent conducting panels, antireflective solar cells, and other broadband metamaterials and stealth technologies. - Highlights: • Making structured metals transparent for ultrabroadband electromagnetic waves. • Non-resonant excitation of surface plasmons or spoof surface plasmons. • Sonic artificially metallic structures transparent for broadband acoustic waves.
Electromagnetic ion cyclotron waves in the plasma depletion layer
Denton, Richard E.; Hudson, Mary K.; Fuselier, Stephen A.; Anderson, Brian J.
1993-01-01
Results of a study of the theoretical properties of electromagnetic ion cyclotron (EMIC) waves which occur in the plasma depletion layer are presented. The analysis assumes a homogeneous plasma with the characteristics which were measured by the AMPTE/CCE satellite at 1450-1501 UT on October 5, 1984. Waves were observed in the Pc 1 frequency range below the hydrogen gyrofrequency, and these waves are identified as EMIC waves. The higher-frequency instability is driven by the temperature anisotropy of the H(+) ions, while the lower-frequency instability is driven by the temperature anisotropy of the He(2+) ions. It is argued that the higher-frequency waves will have k roughly parallel to B(0) and will be left-hand polarized, while the lower frequency wave band will have k oblique to B(0) and will be linearly polarized, in agreement with observations.
A resonant electromagnetic vibration energy harvester for intelligent wireless sensor systems
Energy Technology Data Exchange (ETDEWEB)
Qiu, Jing, E-mail: jingqiu@cqu.edu.cn; Wen, Yumei; Li, Ping; Liu, Xin; Chen, Hengjia; Yang, Jin [Sensors and Instruments Research Center, College of Optoelectronic Engineering, Chongqing University, Chongqing 400044 (China)
2015-05-07
Vibration energy harvesting is now receiving more interest as a means for powering intelligent wireless sensor systems. In this paper, a resonant electromagnetic vibration energy harvester (VEH) employing double cantilever to convert low-frequency vibration energy into electrical energy is presented. The VEH is made up of two cantilever beams, a coil, and magnetic circuits. The electric output performances of the proposed electromagnetic VEH have been investigated. With the enhancement of turns number N, the optimum peak power of electromagnetic VEH increases sharply and the resonance frequency deceases gradually. When the vibration acceleration is 0.5 g, we obtain the optimum output voltage and power of 9.04 V and 50.8 mW at frequency of 14.9 Hz, respectively. In a word, the prototype device was successfully developed and the experimental results exhibit a great enhancement in the output power and bandwidth compared with other traditional electromagnetic VEHs. Remarkably, the proposed resonant electromagnetic VEH have great potential for applying in intelligent wireless sensor systems.
Transmission of electromagnetic waves through sub-wavelength channels
DEFF Research Database (Denmark)
Zhang, Jingjing; Luo, Yu; Mortensen, Asger
2010-01-01
We propose a method of tunneling electromagnetic (EM) waves through a channel with sub-wavelength cross section. By filling the channel with high-ε isotropic material and implementing two matching layers with uniaxial metamterial substrates, the guided waves can go through the narrow channel...... without being cut off, as if it has just passed through the original empty waveguide. Both the magnitude and phase information of the EM fields can be effectively restored after passing this channel, regardless of the polarization of the incoming wave. The performance of this subwavelength channel, which...
Precision cosmology from future lensed gravitational wave and electromagnetic signals.
Liao, Kai; Fan, Xi-Long; Ding, Xuheng; Biesiada, Marek; Zhu, Zong-Hong
2017-10-27
The standard siren approach of gravitational wave cosmology appeals to the direct luminosity distance estimation through the waveform signals from inspiralling double compact binaries, especially those with electromagnetic counterparts providing redshifts. It is limited by the calibration uncertainties in strain amplitude and relies on the fine details of the waveform. The Einstein telescope is expected to produce 10 4 -10 5 gravitational wave detections per year, 50-100 of which will be lensed. Here, we report a waveform-independent strategy to achieve precise cosmography by combining the accurately measured time delays from strongly lensed gravitational wave signals with the images and redshifts observed in the electromagnetic domain. We demonstrate that just 10 such systems can provide a Hubble constant uncertainty of 0.68% for a flat lambda cold dark matter universe in the era of third-generation ground-based detectors.
Electron beam injection during active experiments. I - Electromagnetic wave emissions
Winglee, R. M.; Kellogg, P. J.
1990-01-01
The wave emissions produced in Echo 7 experiment by active injections of electron beams were investigated to determine the properties of the electromagnetic and electrostatic fields for both the field-aligned and cross-field injection in such experiments and to evaluate the sources of free energy and relative efficiencies for the generation of the VLF and HF emissions. It is shown that, for typical beam energies in active experiments, electromagnetic effects do not substantially change the bulk properties of the beam, spacecraft charging, and plasma particle acceleration. Through simulations, beam-generated whistlers; fundamental z-mode and harmonic x-mode radiation; and electrostatic electron-cyclotron, upper-hybrid, Langmuir, and lower-hybrid waves were identified. The characteristics of the observed wave spectra were found to be sensitive to both the ratio of the electron plasma frequency to the cyclotron frequency and the angle of injection relative to the magnetic field.
Electromagnetic Waves Broadcast by a VCR.
Brown, Michael H.
1996-01-01
Presents experiments that use a video cassette recorder (VCR) to demonstrate polarization of radio waves using two dipole antennas and a spark gap transmitter tuned to a frequency of either 60-66 MHz or 66-72 MHz with wavelengths of 5 or 4.3 meters, close to the wavelengths of the original work done by Heinrich Hertz. (JRH)
Success of electromagnetic shock wave lithotripter asmonotherapy ...
African Journals Online (AJOL)
Objectives: To evaluate the success of shock wave lithotripsy (SWL) as monotherapy for solitary renalstones larger than 2 cm without ureteral stenting. Hence, if our study result demonstrates acceptable successand safety, we can recommend ESWL as a treatment option for patients with large renal calculi. Subjects and ...
Electromagnetic Wave Absorption Property of Graphene with FeO4 Nanoparticles.
Yang, Cheng; Dai, Shenglong; Zhang, Xiaoyan; Zhao, Tianyu; Yan, Shaojiu; Zhao, Xiuying
2016-02-01
Nanomaterials consisting of various ratios of Fe3O4 and graphene (defined C-Fe3O4/GR) were pre- pared by an in situ coordination complex hydro-thermal synthesis method. The structure and morphology of the nanomaterials C-Fe3O4/GR obtained were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and transmission electron microscopy (TEM). It was found that the Fe3O4 nanoparticles distributed on the surfaces of graphene, and had a spinel structure and a uniform chemical phase when the weight ratios of Fe3O4 to graphene oxide (GO) were 9:1 or 9:2. It was suggested that GO had been successfully reduced to graphene and the Fe3O4 nanoparticles were chemically bonded to graphene. The SQUID vibrating sample magnetometer (SQUID-VSM) indicated that the maximum of the saturation magnetization was 83.6 emmicro g(-1) when the mass ratio of Fe3O4 to GO was 9:2. Electromagnetic wave absorption showed that the chemical compound of Fe3O4 and graphene had a better electromagnetic property than the mechanical blend of Fe3O4 and graphene (M-Fe3O4/GR). The C-Fe3O4/GR had a reflection loss larger than -10 dB in the frequency range 12.9-17.0 GHz for an absorber thickness of 3 mm, and a maximum reflection loss of -12.3 dB at 14.8 GHz and a maximum reflection loss of -31.2 dB at 10.5 GHz for an absorber thickness of 10 mm. Theoretical analysis showed that the electromagnetic wave absorption behavior obeyed the quarter-wave principles. These results showed that the C-Fe3O4/GR nanomaterials can meet the requirements for some engineering applications, showing great application potential in electromagnetic wave absorption.
A maximally informative version of inelastic scattering of electromagnetic waves by Langmuir waves
International Nuclear Information System (INIS)
Erofeev, V. I.
2015-01-01
The concept of informativeness of nonlinear plasma physics scenarios is explained. Natural ideas of developing highly informative models of plasma kinetics are spelled out. A maximally informative version of inelastic scattering of electromagnetic waves by Langmuir waves in a weakly turbulent inhomogeneous plasma is developed with consideration of possible changes in wave polarization. In addition, a new formula for wave drift in spatial positions and wave vectors is derived. New scenarios of the respective wave drift and inelastic scattering are compared with the previous visions. The results indicate the need for further revision of the traditional understanding of nonlinear plasma phenomena
Topology optimization of vibration and wave propagation problems
DEFF Research Database (Denmark)
Jensen, Jakob Søndergaard
2007-01-01
The method of topology optimization is a versatile method to determine optimal material layouts in mechanical structures. The method relies on, in principle, unlimited design freedom that can be used to design materials, structures and devices with significantly improved performance and sometimes...... novel functionality. This paper addresses basic issues in simulation and topology design of vibration and wave propagation problems. Steady-state and transient wave propagation problems are addressed and application examples for both cases are presented....
Selective generation of ultrasonic Lamb waves by electromagnetic acoustic transducers
International Nuclear Information System (INIS)
Li Ming-Liang; Deng Ming-Xi; Gao Guang-Jian
2016-01-01
In this paper, we describe a modal expansion approach for the analysis of the selective generation of ultrasonic Lamb waves by electromagnetic acoustic transducers (EMATs). With the modal expansion approach for waveguide excitation, an analytical expression of the Lamb wave’s mode expansion coefficient is deduced, which is related to the driving frequency and the geometrical parameters of the EMAT’s meander coil, and lays a theoretical foundation for exactly analyzing the selective generation of Lamb waves with EMATs. The influences of the driving frequency on the mode expansion coefficient of ultrasonic Lamb waves are analyzed when the EMAT’s geometrical parameters are given. The numerical simulations and experimental examinations show that the ultrasonic Lamb wave modes can be effectively regulated (strengthened or restrained) by choosing an appropriate driving frequency of EMAT, with the geometrical parameters given. This result provides a theoretical and experimental basis for selectively generating a single and pure Lamb wave mode with EMATs. (special topic)
Electromagnetic ion cyclotron waves stimulated by modest magnetospheric compressions
Anderson, B. J.; Hamilton, D. C.
1993-01-01
AMPTE/CCE magnetic field and particle data are used to test the suggestion that increased hot proton temperature anisotropy resulting from convection during magnetospheric compression is responsible for the enhancement in Pc 1 emission via generation of electromagnetic ion cyclotron (EMIC) waves in the dayside outer equatorial magnetosphere. The relative increase in magnetic field is used to gauge the strength of the compression, and an image dipole model is used to estimate the motion of the plasma during compression. Proton data are used to analyze the evolution of the proton distribution and the corresponding changes in EMIC wave activity expected during the compression. It is suggested that enhancements in dynamic pressure pump the energetic proton distributions in the outer magnetosphere, driving EMIC waves. Waves are expected to be generated most readily close to the magnetopause, and transient pressure pulses may be associated with bursts of EMIC waves, which would be observed on the ground in association with ionospheric transient signatures.
Social waves in giant honeybees (Apis dorsata) elicit nest vibrations.
Kastberger, Gerald; Weihmann, Frank; Hoetzl, Thomas
2013-07-01
Giant honeybees (Apis dorsata) nest in the open and have developed a wide array of strategies for colony defence, including the Mexican wave-like shimmering behaviour. In this collective response, the colony members perform upward flipping of their abdomens in coordinated cascades across the nest surface. The time-space properties of these emergent waves are response patterns which have become of adaptive significance for repelling enemies in the visual domain. We report for the first time that the mechanical impulse patterns provoked by these social waves and measured by laser Doppler vibrometry generate vibrations at the central comb of the nest at the basic (='natural') frequency of 2.156 ± 0.042 Hz which is more than double the average repetition rate of the driving shimmering waves. Analysis of the Fourier spectra of the comb vibrations under quiescence and arousal conditions provoked by mass flight activity and shimmering waves gives rise to the proposal of two possible models for the compound physical system of the bee nest: According to the elastic oscillatory plate model, the comb vibrations deliver supra-threshold cues preferentially to those colony members positioned close to the comb. The mechanical pendulum model predicts that the comb vibrations are sensed by the members of the bee curtain in general, enabling mechanoreceptive signalling across the nest, also through the comb itself. The findings show that weak and stochastic forces, such as general quiescence or diffuse mass flight activity, cause a harmonic frequency spectrum of the comb, driving the comb as an elastic plate. However, shimmering waves provide sufficiently strong forces to move the nest as a mechanical pendulum. This vibratory behaviour may support the colony-intrinsic information hypothesis herein that the mechanical vibrations of the comb provoked by shimmering do have the potential to facilitate immediate communication of the momentary defensive state of the honeybee nest to
Social waves in giant honeybees ( Apis dorsata) elicit nest vibrations
Kastberger, Gerald; Weihmann, Frank; Hoetzl, Thomas
2013-07-01
Giant honeybees ( Apis dorsata) nest in the open and have developed a wide array of strategies for colony defence, including the Mexican wave-like shimmering behaviour. In this collective response, the colony members perform upward flipping of their abdomens in coordinated cascades across the nest surface. The time-space properties of these emergent waves are response patterns which have become of adaptive significance for repelling enemies in the visual domain. We report for the first time that the mechanical impulse patterns provoked by these social waves and measured by laser Doppler vibrometry generate vibrations at the central comb of the nest at the basic (=`natural') frequency of 2.156 ± 0.042 Hz which is more than double the average repetition rate of the driving shimmering waves. Analysis of the Fourier spectra of the comb vibrations under quiescence and arousal conditions provoked by mass flight activity and shimmering waves gives rise to the proposal of two possible models for the compound physical system of the bee nest: According to the elastic oscillatory plate model, the comb vibrations deliver supra-threshold cues preferentially to those colony members positioned close to the comb. The mechanical pendulum model predicts that the comb vibrations are sensed by the members of the bee curtain in general, enabling mechanoreceptive signalling across the nest, also through the comb itself. The findings show that weak and stochastic forces, such as general quiescence or diffuse mass flight activity, cause a harmonic frequency spectrum of the comb, driving the comb as an elastic plate. However, shimmering waves provide sufficiently strong forces to move the nest as a mechanical pendulum. This vibratory behaviour may support the colony-intrinsic information hypothesis herein that the mechanical vibrations of the comb provoked by shimmering do have the potential to facilitate immediate communication of the momentary defensive state of the honeybee nest to the
Selective wave-transmitting electromagnetic absorber through composite metasurface
Sun, Zhiwei; Zhao, Junming; Zhu, Bo; Jiang, Tian; Feng, Yijun
2017-11-01
Selective wave-transmitting absorbers which have one or more narrow transmission bands inside a wide absorption band are often demanded in wireless communication and radome applications for reducing the coupling between different systems, improving anti-jamming capability, and reducing antennas' radar cross section. Here we propose a feasible method that utilizing composite of two metasurfaces with different polarization dependent characteristics, one works as electromagnetic polarization rotator and the other as a wideband polarization dependent electromagnetic wave absorber. The polarization rotator produces a cross polarization output in the wave-transmitting band, while preserves the polarization of the incidence outside the band. The metasurface absorber works for certain linear polarization with a much wider absorption band covering the wave-transmitting frequency. When combining these two metasurfaces properly, the whole structure behaves as a wideband absorber with a certain frequency transmission window. The proposal may be applied in radome designs to reduce the radar cross section of antenna or improving the electromagnetic compatibility in communication devices.
Surface Acoustic Wave Vibration Sensors for Measuring Aircraft Flutter
Wilson, William C.; Moore, Jason P.; Juarez, Peter D.
2016-01-01
Under NASA's Advanced Air Vehicles Program the Advanced Air Transport Technology (AATT) Project is investigating flutter effects on aeroelastic wings. To support that work a new method for measuring vibrations due to flutter has been developed. The method employs low power Surface Acoustic Wave (SAW) sensors. To demonstrate the ability of the SAW sensor to detect flutter vibrations the sensors were attached to a Carbon fiber-reinforced polymer (CFRP) composite panel which was vibrated at six frequencies from 1Hz to 50Hz. The SAW data was compared to accelerometer data and was found to resemble sine waves and match each other closely. The SAW module design and results from the tests are presented here.
Strip waves in vibrated shear-thickening wormlike micellar solutions
Epstein, T.; Deegan, R. D.
2010-06-01
We present an instability in vertically vibrated dilute wormlike micellar solutions. Above a critical driving acceleration the fluid forms elongated solitary domains of high amplitude waves. We model this instability using a Mathieu equation modified to account for the non-Newtonian character of the fluid. We find that our model successfully reproduces the observed transitions.
International Nuclear Information System (INIS)
Sugaya, Reija
1991-01-01
The velocity-space diffusion equation describing distortion of the velocity distribution function due to resonant wave-wave scattering of electromagnetic and electrostatic waves in an unmagnetized plasma is derived from the Vlasov-Maxwell equations by perturbation theory. The conservation laws for total energy and momentum densities of waves and particles are verified, and the time evolutions of the energy and momentum densities of particles are given in terms of the nonlinear wave-wave coupling coefficient in the kinetic wave equation. (author)
RCS Diversity of Electromagnetic Wave Carrying Orbital Angular Momentum.
Zhang, Chao; Chen, Dong; Jiang, Xuefeng
2017-11-13
An electromagnetic (EM) wave with orbital angular momentum (OAM) has a helical wave front, which is different from that of the plane wave. The phase gradient can be found perpendicular to the direction of propagation and proportional to the number of OAM modes. Herein, we study the backscattering property of the EM wave with different OAM modes, i.e., the radar cross section (RCS) of the target is measured and evaluated with different OAM waves. As indicated by the experimental results, different OAM waves have the same RCS fluctuation for the simple target, e.g., a small metal ball as the target. However, for complicated targets, e.g., two transverse-deployed small metal balls, different RCSs can be identified from the same incident angle. This valuable fact helps to obtain RCS diversity, e.g., equal gain or selective combining of different OAM wave scattering. The majority of the targets are complicated targets or expanded targets; the RCS diversity can be utilized to detect a weak target traditionally measured by the plane wave, which is very helpful for anti-stealth radar to detect the traditional stealth target by increasing the RCS with OAM waves.
Stimulated brillouin scattering of electromagnetic waves in a dusty plasma
International Nuclear Information System (INIS)
Salimullah, M.; Sen, A.
1991-08-01
The stimulated Brilluoin scattering of electromagnetic waves in a homogeneous, unmagnetized and collisionless dusty plasma has been investigated theoretically. The Vlasov equation has been solved perturbatively to find the nonlinear response of the plasma particles. The presence of the dust particles introduces a background inhomogeneous electric field which significantly influences the dispersive properties of the plasma. At the ion acoustic branch we find the usual scattering slightly modified by the charged dust grains. However, at the frequency lower than the ion acoustic branch we find a new mode of the plasma arising from the oscillations of the ions in the static structure of the dust distribution. This low frequency branch causes enhanced stimulated Brillouin scattering of electromagnetic waves in a dusty plasma. (author). 15 refs
Interaction of the electromagnetic waves and non-magnetized plasmas
International Nuclear Information System (INIS)
Sun Aiping; Qiu Xiaoming; Dong Yuying; Li Liqiong
2002-01-01
The propagation of electromagnetic waves with 0.5 - 10 GHz in a non-magnetized collisional plasma slab is studied numerically. The change in the absorbed power, reflected power and transmitted power of the electromagnetic wave with collisional frequency of electrons and neutral atoms in plasma from 0.1 - 10 GHz, is calculated, in the condition of the uniform plasma with density of 10 10 or 10 11 cm -3 and depth of 10 cm, and the non-uniform plasma with density distribution of n = n 0 exp[2(z/d-1)] and depth of 10 cm, respectively. The results show that the absorbed power in either uniform or non-uniform plasma is large when the plasma density is large and collision frequency is high, and the peak value is 90%
On the self-trapping of an electromagnetic wave in magnetized plasma
International Nuclear Information System (INIS)
El-Ashry, M.Y.; Berezhiani, V.I.; Pichkhadze, Sh.D.
1987-06-01
The possibility of relativistic self-trapping of an electromagnetic wave in magnetized plasma is studied. It is shown that in the case of propagation of fast wave packet of electromagnetic wave in plasma, self-trapping is possible due to the effect of relativistic non-linearity, which is effective even for small amplitudes of the pumping wave. (author). 7 refs
Electromagnetic wave propagation in relativistic magnetized plasmas
International Nuclear Information System (INIS)
Weiss, I.
1985-01-01
An improved mathematical technique and a new code for deriving the conductivity tensor for collisionless plasmas have been developed. The method is applicable to a very general case, including both hot (relativistic) and cold magnetized plasmas, with only isotropic equilibrium distributions being considered here. The usual derivation starts from the relativistic Vlasov equation and leads to an integration over an infinite sum of Bessel functions which has to be done numerically. In the new solution the integration is carried out over a product of two Bessel functions only. This reduces the computing time very significantly. An added advantage over existing codes is our capability to perform the computations for waves propagating obliquely to the magnetic field. Both improvements greatly facilitate investigations of properties of the plasma under conditions hitherto unexplored
Saldanha, Pablo L
2010-02-01
It is proposed a natural and consistent division of the momentum of electromagnetic waves in linear, non-dispersive and non-absorptive dielectric and magnetic media into material and electromagnetic parts. The material part is calculated using directly the Lorentz force law and the electromagnetic momentum density has the form epsilon(0)E x B, without an explicit dependence on the properties of the media. The consistency of the treatment is verified through the obtention of a correct momentum balance equation in many examples and showing the compatibility of the division with the Einstein's theory of relativity by the use of a gedanken experiment. An experimental prediction for the radiation pressure on mirrors immersed in linear dielectric and magnetic media is also made.
Dispersion relation of linearly polarized strong electromagnetic waves
Energy Technology Data Exchange (ETDEWEB)
Ferrari, A; Massaglia, S [Consiglio Nazionale delle Ricerche, Turin (Italy). Lab. di Cosmo-Geofisica; Dobrowolny, M [Comitato Nazionale per l' Energia Nucleaire, Frascati (Italy). Lab. Plasma Spazio
1975-12-15
A numerical study is presented of the dispersion relation of linearly polarized strong electromagnetic waves in a cold electron plasma. The nonlinear effects introduced by the relativistic motion of electrons are: (1) the dispersion relation depends explicitly on the field strength ..cap alpha..=eE/sub 0//mc..omega../sub 0/, and (2) the propagation of modes with frequencies below the formal electron plasma frequency is allowed.
Detecting electromagnetic cloaks using backward-propagating waves
Salem, Mohamed
2011-08-01
A novel approach for detecting transformation-optics invisibility cloaks is proposed. The detection method takes advantage of the unusual backward-propagation characteristics of recently reported beams and pulses to induce electromagnetic scattering from the cloak. Even though waves with backward-propagating energy flux cannot penetrate the cloaking shell and interact with the cloaked objects (i.e., they do not make the cloaked object visible), they provide a mechanism for detecting the presence of cloaks. © 2011 IEEE.
Detecting electromagnetic cloaks using backward-propagating waves
Salem, Mohamed; Bagci, Hakan
2011-01-01
A novel approach for detecting transformation-optics invisibility cloaks is proposed. The detection method takes advantage of the unusual backward-propagation characteristics of recently reported beams and pulses to induce electromagnetic scattering from the cloak. Even though waves with backward-propagating energy flux cannot penetrate the cloaking shell and interact with the cloaked objects (i.e., they do not make the cloaked object visible), they provide a mechanism for detecting the presence of cloaks. © 2011 IEEE.
Magnesiothermic reduction of rice husk ash for electromagnetic wave adsorption
Energy Technology Data Exchange (ETDEWEB)
Liu, Shu-Ting; Yan, Kang-kang; Zhang, Yuan hu; Jin, Shi-di; Ye, Ying; Chen, Xue-Gang, E-mail: chenxg83@zju.edu.cn
2015-11-15
The increase in electromagnetic pollution due to the extensive exploitation of electromagnetic (EM) waves in modern technology creates correspondingly urgent need for developing effective EM wave absorbers. In this study, we carried out the magnesiothermic reduced the rice husk ash under different temperatures (400–800 °C) and investigated the electromagnetic wave adsorption of the products. The EM absorbing for all samples are mainly depend on the dielectric loss, which is ascribed to the carbon and silicon carbide content. RA samples (raw rice husk ashed in air and was magesiothermic reduced in different temperatures) exhibit poor dielectric properties, whereas RN samples (raw rice husk ashed in nitrogen and was magesiothermic reduced in different temperatures) with higher content of carbon and silicon carbide display considerable higher dielectric loss values and broader bandwidth for RL<−5 dB and −10 dB. For RN samples, the maximum bandwidth for −5 dB and −10 dB decrease with carbon contents, while the optimum thickness decrease with increasing SiC content. The optimum thickness of RN400–800 for EM absorption is 1.5–2.0 mm, with maximum RL of between −28.9 and −68.4 dB, bandwidth of 6.7–13 GHz for RL<−5 dB and 3.2–6.2 GHz for RL<−10 dB. The magnesiothermic reduction will enhance the potential application of rice husk ash in EM wave absorption and the samples benefited from low bulk density and low thickness. With the advantages of light-weight, high EM wave absorption, low cost, RN400–800 could be promising candidates for light-weight EM wave absorption materials over many conventional EM wave absorbers. - Highlights: • RN400–800 samples are potential light-weight electromagnetic absorbers. • Carbon and SiC are considered as dominating contributions for the dielectric loss. • Magnesiumothermic reduction extends the EM wave absorption potential of RHN.
Particle Dynamics under Quasi-linear Interaction with Electromagnetic Waves
Energy Technology Data Exchange (ETDEWEB)
Castejon, F.; Eguilior, S.
2003-07-01
Langevin equations for quasi-linear wave particle interaction are obtained taking advantage of the unique vocal equivalence between Fokker-Plank equation and the former ones. Langevin equations are solved numerically and, hence, the evolution of a single particle embedded in an electromagnetic field in momentum space is obtained. The equations are relativistic and valid for any wave. It is also shown that the stochastic part of the equations is negligible in comparison with the deterministic term, except for the momentum to the resonance condition for the main parallel refractive index. (Author) 24 refs.
Particle Dynamics under Quasi-linear Interaction with Electromagnetic Waves
International Nuclear Information System (INIS)
Castejon, F.; Eguilior, S.
2003-01-01
Langevin equations for quasi-linear wave particle interaction are obtained taking advantage of the unique vocal equivalence between Fokker-Plank equation and the former ones. Langevin equations are solved numerically and, hence, the evolution of a single particle embedded in an electromagnetic field in momentum space is obtained. The equations are relativistic and valid for any wave. It is also shown that the stochastic part of the equations is negligible in comparison with the deterministic term, except for the momentum to the resonance condition for the main parallel refractive index. (Author) 24 refs
Theory of electromagnetic wave propagation in ferromagnetic Rashba conductor
Shibata, Junya; Takeuchi, Akihito; Kohno, Hiroshi; Tatara, Gen
2018-02-01
We present a comprehensive study of various electromagnetic wave propagation phenomena in a ferromagnetic bulk Rashba conductor from the perspective of quantum mechanical transport. In this system, both the space inversion and time reversal symmetries are broken, as characterized by the Rashba field α and magnetization M, respectively. First, we present a general phenomenological analysis of electromagnetic wave propagation in media with broken space inversion and time reversal symmetries based on the dielectric tensor. The dependence of the dielectric tensor on the wave vector q and M is retained to first order. Then, we calculate the microscopic electromagnetic response of the current and spin of conduction electrons subjected to α and M, based on linear response theory and the Green's function method; the results are used to study the system optical properties. First, it is found that a large α enhances the anisotropic properties of the system and enlarges the frequency range in which the electromagnetic waves have hyperbolic dispersion surfaces and exhibit unusual propagations known as negative refraction and backward waves. Second, we consider the electromagnetic cross-correlation effects (direct and inverse Edelstein effects) on the wave propagation. These effects stem from the lack of space inversion symmetry and yield q-linear off-diagonal components in the dielectric tensor. This induces a Rashba-induced birefringence, in which the polarization vector rotates around the vector (α ×q ) . In the presence of M, which breaks time reversal symmetry, there arises an anomalous Hall effect and the dielectric tensor acquires off-diagonal components linear in M. For α ∥M , these components yield the Faraday effect for the Faraday configuration q ∥M and the Cotton-Mouton effect for the Voigt configuration ( q ⊥M ). When α and M are noncollinear, M- and q-induced optical phenomena are possible, which include nonreciprocal directional dichroism in the
Electromagnetic ion cyclotron waves observed in the plasma depletion layer
Anderson, B. J.; Fuselier, S. A.; Murr, D.
1991-01-01
Observations from AMPTE/CCE in the earth's magnetosheath on October 5, 1984 are presented to illustrate 0.1 - 4.0 Hz magnetic field pulsations in the subsolar plasma depletion layer (PDL) for northward sheath field during a magnetospheric compression. The PDL is unambiguously identified by comparing CCE data with data from IRM in the upstream solar wind. Pulsations in the PDL are dominated by transverse waves with F/F(H+) 1.0 or less and a slot in spectral power at F/F(H+) = 0.5. The upper branch is left hand polarized while the lower branch is linearly polarized. In the sheath the proton temperature anisotropy is about 0.6 but it is about 1.7 in the PDL during wave occurrence. The properties and correlation of waves with increased anisotropy indicate that they are electromagnetic ion cyclotron waves.
Electromagnetic wave theory for boundary-value problems an advanced course on analytical methods
Eom, Hyo J
2004-01-01
Electromagnetic wave theory is based on Maxwell's equations, and electromagnetic boundary-value problems must be solved to understand electromagnetic scattering, propagation, and radiation. Electromagnetic theory finds practical applications in wireless telecommunications and microwave engineering. This book is written as a text for a two-semester graduate course on electromagnetic wave theory. As such, Electromagnetic Wave Theory for Boundary-Value Problems is intended to help students enhance analytic skills by solving pertinent boundary-value problems. In particular, the techniques of Fourier transform, mode matching, and residue calculus are utilized to solve some canonical scattering and radiation problems.
A differentiated plane wave as an electromagnetic vortex
International Nuclear Information System (INIS)
Hannay, J H; Nye, J F
2015-01-01
Differentiating a complex scalar plane wave with respect to its direction produces an isolated straight vortex line and has a natural extension, described in earlier papers, to the vector waves of electromagnetism—a differentiated plane wave (DPW). It epitomizes destructive interference and will be shown to have the local structure of an electromagnetic vortex. In this paper its polarization structure and Poynting vector field are compared and contrasted with that of the family of linear polynomial waves, of which it is a special member. By definition this wider family has a general linear complex vector function of position multiplying a plane wave, but the function must be such that the combination satisfies Maxwell’s equations. This forces translational invariance of the function along the wavevector direction—in other words the wave is ‘non-diffracting’. In a natural sense all possible polarizations are exhibited once only. But the DPW has a distinctive polarization structure only partly explored previously. Both classes of waves share similar Poynting vector fields, which can be ‘elliptic’ (helix-like flow lines) or ‘hyperbolic’, of a repulsive nature, unexpected for a vortex. Both classes can be considered as a limit in the superposition of three closely parallel ordinary plane waves in destructive interference, and this derivation is supplied in full here. (paper)
International Nuclear Information System (INIS)
Bahar, E.
1976-01-01
The propagation of electromagnetic waves excited by electric dipoles oriented along the axis of multilayered spheroidal structures of finite conductivity is investigated. The electromagnetic parameters and the thickness of the layers of the structure are assumed to be functions of the latitude. In the analysis, electric and magnetic field transforms that constitute a discrete and a continuous spectrum of spherical waves are used to provide a suitable basis for the expansion of the electromagnetic fields at any point in the irregular spheroidal structure. For spheroidal structures with good conducting cores, the terms in the solutions associated with the continuous part of the wave spectrum vanish. In general, however, when the skin depth for the core is large compared to its dimensions or when the sources are located in the core of the structure and propagation in the core is of special interest, the contribution from the continuous part of the wave spectrum cannot be neglected. At each interface between the layers of the irregular spheroidal structure, exact boundary conditions are imposed. Since the terms of the field expansions in the irregular structure do not individually satisfy the boundary conditions, Maxwell's equations are reduced to sets of coupled ordinary first-order differential equations for the wave amplitudes. The solutions are shown to satisfy the reciprocity relationships in electromagnetic theory. The analysis may be applied to problems of radio wave propagation in a nonuniform model of the earth-ionosphere waveguide, particularly when focusing effects at the antipodes are important
Quantifying Electromagnetic Wave Propagation Environment Using Measurements From A Small Buoy
2017-06-01
ELECTROMAGNETIC WAVE PROPAGATION ENVIRONMENT USING MEASUREMENTS FROM A SMALL BUOY by Andrew E. Sweeney June 2017 Thesis Advisor: Qing Wang...TYPE AND DATES COVERED Master’s thesis 4. TITLE AND SUBTITLE QUANTIFYING ELECTROMAGNETIC WAVE PROPAGATION ENVIRONMENT USING MEASUREMENTS FROM A...the Coupled Air Sea Processes and Electromagnetic (EM) ducting Research (CASPER), to understand air-sea interaction processes and their representation
Seomun, GyeongAe; Kim, YoungHwan; Lee, Jung-Ah; Jeong, KwangHoon; Park, Seon-A; Kim, Miran; Noh, Wonjung
2014-01-01
To better understand environmental electromagnetic wave exposure during the use of digital textbooks by elementary school students, we measured numeric values of the electromagnetic fields produced by tablet personal computers (TPCs). Specifically, we examined the distribution of the electromagnetic waves for various students' seating positions in…
International Nuclear Information System (INIS)
Tagirov, Eh.A.
1985-01-01
A model of resonance parametric transformation of a gravitational wave to electromagnetic one is considered. Two plane monochromatic waves: a strong electromagnetic and weak gravitational - interacting in a medium generate at difference and sum frequencies an electromagnetic wave in a direction determined with the condition of spatial wave synchronism. Rarefied cold gas or beam of elementary emitters (''molecules'') serve as a medium model. Coefficients of parametric transformation have been determined
Wave-induced Ship Hull Vibrations in Stochastic Seaways
DEFF Research Database (Denmark)
Jensen, Jørgen Juncher; Dogliani, M.
1996-01-01
A theoretical Study is undertaken on the determination of wave-induced loads in flexible ship hulls. The calculations are performed within the framework of a non-linear, quadratic strip theory formulated in the frequency domain. Included are non-linear effects due to changes in added mass......, hydrodynamic damping and water line breadth with sectional immersion in waves. The study is limited to continuous excitations from the waves and thus transient so-called whipping vibrations due to slamming loads are not considered.Because of the non-linearities the ship hull responses become non...... to the large separation between dominating wave frequencies and the lowest two-node frequency of the hull beam. Both extreme value predictions and fatigue damage are considered.For a fast container ship the rigid body and two-node (springing) vertical wave-induced bending moments amidship are calculated...
Electron beam injection during active experiments. 1. Electromagnetic wave emissions
International Nuclear Information System (INIS)
Winglee, R.M.; Kellogg, P.J.
1990-01-01
During the active injection of an electron beam, a broad spectrum of waves is generated. In this paper examples of spectra from the recent Echo 7 experiment are presented. These results show that the characteristics of the emissions can change substantially with altitude. Two-dimensional (three velocity) relativistic electromagnetic particle simulations are used to investigate the changes in the plasma conditions required to account for the observed spectral variations. It is shown that many of these variations can be accounted for by assuming that the ratio of the electron plasma frequency ω pe to cyclotron frequency Ω e is less than unity at the lower altitudes of about 200 km and near or above unity at apogee of about 300 km. In the former case, whistlers with a cutoff at ω pe , lower hybrid and plasma waves are driven by the parallel beam energy while electromagnetic fundamental z mode and second harmonic x mode and electrostatic upper hybrid waves are driven by the perpendicular beam energy through the master instability. E x B drifts driven by perpendicular electric fields associated with the beam-plasma interaction can also be important in generating maser emission, particularly for field-aligned injection where there is no intrinsic perpendicular beam energy. The power in the electrostatic waves is a few percent of the beam energy and that in the electromagnetic waves a few tenths of a percent. In the latter case, where ω pe /Ω e increases above unity, emission in the fundamental z mode and second harmonic x mode become suppressed
Electromagnetic energy harvesting from vibrations of multiple frequencies
International Nuclear Information System (INIS)
Yang Bin; Lee Chengkuo; Xie Jin; Han He, Johnny; Kotlanka, Rama Krishna; Feng Hanhua; Xiang Wenfeng; Low, Siew Ping
2009-01-01
A novel multi-frequency energy harvester has been designed and fabricated, which consists of three permanent magnets, three sets of two-layer copper coils and a supported beam of acrylic, while these coils are made of thin fire resistant 4 (FR4) substrates using a standard printed circuit board. The energy under the first, second and third resonant modes can be harvested, corresponding to the resonant frequencies of 369 Hz, 938 Hz and 1184 Hz, respectively. The maximum output voltage and power of the first and second vibration modes are 1.38 mV, 0.6 µW and 3.2 mV, 3.2 µW for a 14 µm exciting vibration amplitude and a 0.4 mm gap between the magnet and coils, respectively. The feasibility study results are in good agreement with the theoretical calculations and show promising application potentials
Multi-resonant electromagnetic shunt in base isolation for vibration damping and energy harvesting
Pei, Yalu; Liu, Yilun; Zuo, Lei
2018-06-01
This paper investigates multi-resonant electromagnetic shunts applied to base isolation for dual-function vibration damping and energy harvesting. Two multi-mode shunt circuit configurations, namely parallel and series, are proposed and optimized based on the H2 criteria. The root-mean-square (RMS) value of the relative displacement between the base and the primary structure is minimized. Practically, this will improve the safety of base-isolated buildings subjected the broad bandwidth ground acceleration. Case studies of a base-isolated building are conducted in both the frequency and time domains to investigate the effectiveness of multi-resonant electromagnetic shunts under recorded earthquake signals. It shows that both multi-mode shunt circuits outperform traditional single mode shunt circuits by suppressing the first and the second vibration modes simultaneously. Moreover, for the same stiffness ratio, the parallel shunt circuit is more effective at harvesting energy and suppressing vibration, and can more robustly handle parameter mistuning than the series shunt circuit. Furthermore, this paper discusses experimental validation of the effectiveness of multi-resonant electromagnetic shunts for vibration damping and energy harvesting on a scaled-down base isolation system.
Non linear dynamic of Langmuir and electromagnetic waves in space plasmas
International Nuclear Information System (INIS)
Guede, Jose Ricardo Abalde
1995-11-01
The aim of this work is to study the nonlinear dynamics of Langmuir and electromagnetic waves in space plasmas. Firstly, the generalized Zakharov equations are derived which are used to study the hybrid parametric instability involving the generation of daughter Langmuir, electromagnetic and ion-acoustic waves induced by two counter-propagating Langmuir pump waves with different amplitudes based on a coupled dispersion relation. Secondly, starting from the generalized Zakharov equations the linear and nonlinear coupled mode theories of three-wave and four-wave parametric interactions are developed, respectively. In three-waves processes, a Langmuir wave decays into another Langmuir wave and an ion-acoustic wave (electrostatic parametric decay) or into an electromagnetic wave and an ion-acoustic wave (electromagnetic parametric decay). In four-wave (modulational) processes, the interaction involves two wave triplets: in the decay triplet a pump wave couples with a low-frequency wave to generate a Stokes wave, and in the fusion triplets: in the decay triplet a pump wave couples with a low-frequency wave to generate a Stokes wave, and in the fusion triplet the coupling of a pump wave with a low-frequency wave generate an anti-Stokes wave. These modulational processes are convective and resonant processes wherein the low-frequency modes are Eigenmodes of plasma and are known as the stimulated modulational processes. Four such processes are investigated in this thesis: two with Langmuir pump waves (electrostatic and hybrid stimulated modulation processes) and the other two with electromagnetic pump waves (stimulated modulation Brillouin scattering and electromagnetic stimulated modulation process). Applications of the theoretical results in space plasmas are discussed. In particular, it is shown that the electrostatic and electromagnetic parametric decay processes of Langmuir waves can model the generation and modulation of radio emissions and Langmuir waves in the
On propagation of electromagnetic and gravitational waves in the expanding Universe
International Nuclear Information System (INIS)
Gladyshev, V O
2016-01-01
The purpose of this study was to obtain an equation for the propagation time of electromagnetic and gravitational waves in the expanding Universe. The velocity of electromagnetic waves propagation depends on the velocity of the interstellar medium in the observer's frame of reference. Gravitational radiation interacts weakly with the substance, so electromagnetic and gravitational waves propagate from a remote astrophysical object to the terrestrial observer at different time. Gravitational waves registration enables the inverse problem solution - by the difference in arrival time of electromagnetic and gravitational-wave signal, we can determine the characteristics of the emitting area of the astrophysical object. (paper)
Interaction of electromagnetic and acoustic waves in a stochastic atmosphere
Bhatnagar, N.; Peterson, A. M.
1979-01-01
In the Stanford radio acoustic sounding system (RASS) an electromagnetic signal is made to scatter from a moving acoustic pulse train. Under a Bragg-scatter condition maximum electromagnetic scattering occurs. The scattered radio signal contains temperature and wind information as a function of the acoustic-pulse position. In this investigation RASS performance is assessed in an atmosphere characterized by the presence of turbulence and mean atmospheric parameters. The only assumption made is that the electromagnetic wave is not affected by stochastic perturbations in the atmosphere. It is concluded that the received radio signal depends strongly on the intensity of turbulence for altitudes of the acoustic pulse greater than the coherence length of propagation. The effect of mean vertical wind and mean temperature on the strength of the received signal is also demonstrated to be insignificant. Mean horizontal winds, however, shift the focus of the reflected electromagnetic energy from its origin, resulting in a decrease in received signal level when a monostatic radio-frequency (RF) system is used. For a bistatic radar configuration with space diversified receiving antennas, the shifting of the acoustic pulse makes possible the remote measurement of the horizontal wind component.
Studying Lorentz-violating electromagnetic waves in confined media
International Nuclear Information System (INIS)
Viana, Davidson R.; Gomes, Andre H.; Fonseca, Jakson M.; Moura-Melo, Winder A.
2009-01-01
Full text. Planck energy scale is still far beyond current possibilities. A question of interest is whether the Lorentz symmetry remains valid at these extremely high energies, whose answer certainly would be useful whenever building grand unified theories, in which general relativity is consistently accommodated. Here, we study a reminiscent of this possible symmetry violation, incorporated in the body of the so-called Standard Model Extension (SME). More precisely, we deal with the pure (Abelian) gauge sector, so that we have a modified classical electromagnetism in (3+1) dimensions, whose Lagrangian include a term proportional to a (constant) background tensor that breaks the Lorentz symmetry, but respecting CPT. Our attention is devoted to the wave-like solutions constrained to propagate inside confined media, like waveguides and resonant cavities. Our preliminary findings indicate that Lorentz-breaking implies in modifications of the standard results which are proportional to the (very small) violating parameters, but could be largely enhanced by diminishing the size of the confined media. Under study is the case of a toroidal cavity where the electromagnetic field should respect the additional requirement of being single-valued in the (toroidal) angular variable. Perhaps, such an extra feature combined with the usual boundary conditions could lead us to large effects of this violation, somewhat similar to those predicted for CPT- and Lorentz-odd electromagnetic waves constrained to propagate along a hollow conductor waveguide. (author)
Utilization Of Carbon Nanotubes In Electromagnetic Wave Detectors
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Muhammad Hanis Zakariah
2017-08-01
Full Text Available Direct detection of hydrocarbon by an active source using electromagnetic (EM energy termed seabed logging (SBL has shown very promising results. However, currently available electromagnetic wave technology has a number of challenges include sensitivity and frequency matching. This paper presents development of the carbon nanotubes (CNTs as electromagnetic wave detector due to outstanding properties of carbon nanotubes. They are currently one of the desired materials for advanced technologies. Two types of detectors were developed in this work, carbon nanotube-based (D1 and without nanotube-based (D2 detectors. Various configuration and arrangement for each type of detector were investigated to determine the one with the highest detection measurement and stability of frequency stability of detection system. It was found that 20 turn-coils coil placed at its centre gives the maximum detection of induction voltage, 39.61 mV. However, the 20 turn- coils with CNTs which gives 36.50 mV is the preferred EM detectors due to the stability in frequency of the detection system.
Electromagnetic Cyclotron Waves in the Solar Wind: Wind Observation and Wave Dispersion Analysis
Jian, L. K.; Moya, P. S.; Vinas, A. F.; Stevens, M.
2016-01-01
Wind observed long-lasting electromagnetic cyclotron waves near the proton cyclotron frequency on 11 March 2005, in the descending part of a fast wind stream. Bi-Maxwellian velocity distributions are fitted for core protons, beam protons, and alpha-particles. Using the fitted plasma parameters we conduct kinetic linear dispersion analysis and find ion cyclotron and/or firehose instabilities grow in six of 10 wave intervals. After Doppler shift, some of the waves have frequency and polarization consistent with observation, thus may be correspondence to the cyclotron waves observed.
Electromagnetic signals produced by elastic waves in the Earth's crust
Sgrigna, V.; Buzzi, A.; Conti, L.; Guglielmi, A. V.; Pokhotelov, O. A.
2004-03-01
The paper describes the excitation of geoelectromagnetic-field oscillations caused by elastic waves propagating in the Earth's crust and generated by natural and anthropogenic phenomena, such as earthquakes, explosions, etc. Two mechanisms of electromagnetic signal generation, i.e. induction and electrokinetics ones, are considered and a comparative analysis between them is carried out. The first mechanism is associated with the induction of Foucault currents due to movements of the Earth's crust in the core geomagnetic field. The second mechanism is connected with movements of liquids filling pores and cracks of rocks. An equation is derived for describing in a uniform way these two manifestations of seismomagnetism. The equation is solved for body and surface waves. The study shows that a magnetic precursor signal is moving in the front of elastic waves.
Nonlinear electromagnetic waves in a degenerate electron-positron plasma
Energy Technology Data Exchange (ETDEWEB)
El-Labany, S.K., E-mail: skellabany@hotmail.com [Department of Physics, Faculty of Science, Damietta University, New Damietta (Egypt); El-Taibany, W.F., E-mail: eltaibany@hotmail.com [Department of Physics, College of Science for Girls in Abha, King Khalid University, Abha (Saudi Arabia); El-Samahy, A.E.; Hafez, A.M.; Atteya, A., E-mail: ahmedsamahy@yahoo.com, E-mail: am.hafez@sci.alex.edu.eg, E-mail: ahmed_ateya2002@yahoo.com [Department of Physics, Faculty of Science, Alexandria University, Alexandria (Egypt)
2015-08-15
Using the reductive perturbation technique (RPT), the nonlinear propagation of magnetosonic solitary waves in an ultracold, degenerate (extremely dense) electron-positron (EP) plasma (containing ultracold, degenerate electron, and positron fluids) is investigated. The set of basic equations is reduced to a Korteweg-de Vries (KdV) equation for the lowest-order perturbed magnetic field and to a KdV type equation for the higher-order perturbed magnetic field. The solutions of these evolution equations are obtained. For better accuracy and searching on new features, the new solutions are analyzed numerically based on compact objects (white dwarf) parameters. It is found that including the higher-order corrections results as a reduction (increment) of the fast (slow) electromagnetic wave amplitude but the wave width is increased in both cases. The ranges where the RPT can describe adequately the total magnetic field including different conditions are discussed. (author)
Induced wave propagation from a vibrating containment envelope
International Nuclear Information System (INIS)
Stout, R.B.; Thigpen, L.; Rambo, J.T.
1985-09-01
Low frequency wave forms are observed in the particle velocity measurements around the cavity and containment envelope formed by an underground nuclear test. The vibration solution for a spherical shell is used to formulate a model for the low frequency wave that propagates outward from this region. In this model the containment envelope is the zone of material that is crushed by the compressive shock wave of the nuclear explosion. The containment envelope is approximated by a spherical shell of material. The material in the spherical shell is densified and is given a relatively high kinetic energy density because of the high compressive stress and particle velocity of the shock wave. After the shock wave has propagated through the spherical shell, the spherical shell vibrates in order to dissipate the kinetic energy acquired from the shock wave. Based on the model, the frequency of vibration depends on the dimensions and material properties of the spherical shell. The model can also be applied in an inverse mode to obtain global estimates of averaged materials properties. This requires using experimental data and semi-empirical relationships involving the material properties. A particular case of estimating a value for shear strength is described. Finally, the oscillation time period of the lowest frequency from five nuclear tests is correlated with the energy of the explosion. The correlation provides another diagnostic to estimate the energy of a nuclear explosion. Also, the longest oscillation time period measurement provides additional experimental data that can be used to assess and validate various computer models. 11 refs., 2 figs
Reflection and transmission of electromagnetic waves in planarly stratified media
International Nuclear Information System (INIS)
Caviglia, G.
1999-01-01
Propagation of time-harmonic electromagnetic waves in planarly stratified multilayers is investigated. Each layer is allowed to be inhomogeneous and the layers are separated by interfaces. The procedure is based on the representation of the electromagnetic field in the basis of the eigenvectors of the matrix characterizing the first-order system. Hence the local reflection and transmission matrices are defined and the corresponding differential equations, in the pertinent space variable are determined. The jump conditions at interfaces are also established. The present model incorporates dissipative materials and the procedure holds without any restrictions to material symmetries. Differential equations appeared in the literature are shown to hold in particular (one-dimensional) cases or to represent homogeneous layers only
Optimizing searches for electromagnetic counterparts of gravitational wave triggers
Coughlin, Michael W.; Tao, Duo; Chan, Man Leong; Chatterjee, Deep; Christensen, Nelson; Ghosh, Shaon; Greco, Giuseppe; Hu, Yiming; Kapadia, Shasvath; Rana, Javed; Salafia, Om Sharan; Stubbs11, Christopher
2018-04-01
With the detection of a binary neutron star system and its corresponding electromagnetic counterparts, a new window of transient astronomy has opened. Due to the size of the sky localization regions, which can span hundreds to thousands of square degrees, there are significant benefits to optimizing tilings for these large sky areas. The rich science promised by gravitational-wave astronomy has led to the proposal for a variety of proposed tiling and time allocation schemes, and for the first time, we make a systematic comparison of some of these methods. We find that differences of a factor of 2 or more in efficiency are possible, depending on the algorithm employed. For this reason, with future surveys searching for electromagnetic counterparts, care should be taken when selecting tiling, time allocation, and scheduling algorithms to optimize counterpart detection.
Propagation of electromagnetic waves in a weakly ionized dusty plasma
International Nuclear Information System (INIS)
Jia, Jieshu; Yuan, Chengxun; Gao, Ruilin; Wang, Ying; Liu, Yaoze; Gao, Junying; Zhou, Zhongxiang; Sun, Xiudong; Li, Hui; Wu, Jian; Pu, Shaozhi
2015-01-01
Propagation properties of electromagnetic (EM) waves in weakly ionized dusty plasmas are the subject of this study. Dielectric relation for EM waves propagating at a weakly ionized dusty plasma is derived based on the Boltzmann distribution law while considering the collision and charging effects of dust grains. The propagation properties of EM energy in dusty plasma of rocket exhaust are numerically calculated and studied, utilizing the parameters of rocket exhaust plasma. Results indicate that increase of dust radius and density enhance the reflection and absorption coefficient. High dust radius and density make the wave hardly transmit through the dusty plasmas. Interaction enhancements between wave and dusty plasmas are developed through effective collision frequency improvements. Numerical results coincide with observed results by indicating that GHz band wave communication is effected by dusty plasma as the presence of dust grains significantly affect propagation of EM waves in the dusty plasmas. The results are helpful to analyze the effect of dust in plasmas and also provide a theoretical basis for the experiments. (paper)
Explaining Electromagnetic Plane Waves in a Vacuum at the Introductory Level
Allred, Clark L.; Della-Rose, Devin J.; Flusche, Brian M.; Kiziah, Rex R.; Lee, David J.
2010-01-01
A typical introduction to electromagnetic waves in vacuum is illustrated by the following quote from an introductory physics text: "Maxwell's equations predict that an electromagnetic wave consists of oscillating electric and magnetic fields. The changing fields induce each other, which maintains the propagation of the wave; a changing electric…
Ganguli, G.; Crabtree, C. E.; Rudakov, L.; Mithaiwala, M.
2014-12-01
Velocity ring instabilities are a common naturally occuring magnetospheric phenomenon that can also be generated by man made ionospheric experiments. These instabilities are known to generate lower-hybrid waves, which generally cannot propagte out of the source region. However, nonlinear wave physics can convert these linearly driven electrostatic lower-hybrid waves into electromagnetic waves that can escape the source region. These nonlinearly generated waves can be an important source of VLF turbulence that controls the trapped electron lifetime in the radiation belts. We develop numerical solutions to the wave-kinetic equation in a periodic box including the effects of nonlinear (NL) scattering (nonlinear Landau damping) of Lower-hybrid waves giving the evolution of the wave-spectra in wavenumber space. Simultaneously we solve the particle diffusion equation of both the background plasma particles and the ring ions, due to both linear and nonlinear Landau resonances. At initial times for cold ring ions, an electrostatic beam mode is excited, while the kinetic mode is stable. As the instability progresses the ring ions heat, the beam mode is stabilized, and the kinetic mode destabilizes. When the amplitude of the waves becomes sufficient the lower-hybrid waves are scattered (by either nearly unmagnetized ions or magnetized electrons) into electromagnetic magnetosonic waves [Ganguli et al 2010]. The effect of NL scattering is to limit the amplitude of the waves, slowing down the quasilinear relaxation time and ultimately allowing more energy from the ring to be liberated into waves [Mithaiwala et al. 2011]. The effects of convection out of the instability region are modeled, additionally limiting the amplitude of the waves, allowing further energy to be liberated from the ring [Scales et al., 2012]. Results are compared to recent 3D PIC simulations [Winske and Duaghton 2012].
Langmuir wave turbulence generated by electromagnetic waves in the laboratory and the ionosphere
International Nuclear Information System (INIS)
Lee, M.C.; Riddolls, R.J.; Moriarty, D.T.; Dalrymple, N.E.; Rowlands, M.J.
1996-01-01
The authors will present some recent results of the laboratory experiments at MIT, using a large plasma device known as the Versatile Toroidal Facility (VTF). These experiments are aimed at cross-checking the ionospheric plasma heating experiments at Arecibo, Puerto Rico using an HF heating facility (heater). The plasma phenomenon under investigation is the spectral characteristic of Langmuir wave turbulence produced by ordinary (o-mode) electromagnetic pump waves. The Langmuir waves excited by o-mode heaters waves at Arecibo have both a frequency-upshifted spectrum and a frequency-downshifted (viz., cascading) spectrum. While the cascading spectrum can be well explained in terms of the parametric decay instability (PDI), the authors have interpreted the frequency-upshifted Langmuir waves to be anti-Stokes Langmuir waves produced by a nonlinear scattering process as follows. Lower hybrid waves creates presumably by lightning-induced whistler waves can scatter nonlinearly the PDI-excited mother langmuir waves, yielding obliquely propagating langmuir waves with frequencies as the summation of the mother Langmuir wave frequencies and the lower hybrid wave frequencies. This suggested process has been confirmed in the laboratory experiments, that can reproduce the characteristic spectra of Langmuir wave turbulence observed in the Arecibo experiments
Virtual Singular Scattering of Electromagnetic Waves in Transformation Media Concept
Directory of Open Access Journals (Sweden)
M. Y. Barabanenkov
2012-07-01
Full Text Available If a scatterer and an observation point (receive both approach the so-called near field zone of a source of electromagnetic waves, the scattering process becomes singular one which is mathematically attributed to the spatial singularity of the free space Green function at the origin. Starting from less well known property of left-handed material slab to transfer the singularity of the free space Green function by implementing coordinate transformation, we present a phenomenon of virtual singular scattering of electromagnetic wave on an inhomogeneity located in the volume of left – handed material slab. Virtual singular scattering means that a scatterer is situated only virtually in the near field zone of a source, being, in fact, positioned in the far field zone. Such a situation is realized if a scatterer is embedded into a flat Veselago’s lens and approaches the lens’s inner focus because a slab of Veselago medium produces virtual sources inside and behind the slab and virtual scatterer (as a source of secondary waves from both slab sides. Considering a line-like dielectric scatterer we demonstrate that the scattering efficiency is proportional to product of singular quasistatic parts of two empty space Green functions that means a multiplicative quasistatic singularity of the Green function for a slab of inhomogeneous Veselago medium. We calculate a resonance value of the scattering amplitude in the regime similar to the known Mie resonance scattering.
Scattering of electromagnetic waves by a traversable wormhole
Directory of Open Access Journals (Sweden)
B. Nasr Esfahani
2005-09-01
Full Text Available Replacing the wormhole geometry with an equivalent medium using the perturbation theory of scattering and the Born approximation, we have calculated the differential scattering cross section of electromagnetic waves by a traversable wormhole. It is shown that scattering at long wavelenghts can essentially distinguish wormhole from ordinary scattering object. Some of the zeros of the scattering cross section are determined which can be used for estimating the radius of the throat of wormholes. The known result that in this kind of scattering the linear polarization remains unchanged is verified here.
RF electromagnetic wave absorbing properties of ferrite polymer composite materials
International Nuclear Information System (INIS)
Dosoudil, Rastislav; Usakova, Marianna; Franek, Jaroslav; Slama, Jozef; Olah, Vladimir
2006-01-01
The frequency dispersion of complex initial (relative) permeability (μ * =μ ' -jμ ' ') and the electromagnetic wave absorbing properties of composite materials based on NiZn sintered ferrite and a polyvinylchloride (PVC) polymer matrix have been studied in frequency range from 1MHz to 1GHz. The complex permeability of the composites was found to increase as the ferrite content increased, and was characterized by frequency dispersion localized above 50MHz. The variation of return loss (RL) of single-layer RF absorbers using the prepared composite materials has been investigated as a function of frequency, ferrite content and the thickness of the absorbers
Integral Equation Methods for Electromagnetic and Elastic Waves
Chew, Weng; Hu, Bin
2008-01-01
Integral Equation Methods for Electromagnetic and Elastic Waves is an outgrowth of several years of work. There have been no recent books on integral equation methods. There are books written on integral equations, but either they have been around for a while, or they were written by mathematicians. Much of the knowledge in integral equation methods still resides in journal papers. With this book, important relevant knowledge for integral equations are consolidated in one place and researchers need only read the pertinent chapters in this book to gain important knowledge needed for integral eq
Application of electromagnetic and sound waves in nutritional assessment
International Nuclear Information System (INIS)
Heymsfield, S.B.; Rolandelli, R.; Casper, K.; Settle, R.G.; Koruda, M.
1987-01-01
Four relatively new techniques that apply electromagnetic or sound waves promise to play a major role in the study of human body composition and in clinical nutritional assessment. Computerized axial tomography, nuclear magnetic resonance, infrared interactance, and ultrasonography provide capabilities for measuring the following: total body and regional fat volume; regional skeletal muscle volume; brain, liver, kidney, heart, spleen, and tumor volume; lean tissue content of triglyceride, iron, and high-energy intermediates; bone density; and cardiac function. Each method is reviewed with regard to basic principles, research and clinical applications, strengths, and limitations.33 references
Diffraction of Electromagnetic Waves on a Waveguide Joint
Directory of Open Access Journals (Sweden)
Malykh Mikhail
2018-01-01
Full Text Available In general, the investigation of the electromagnetic field in an inhomogeneous waveguide doesn’t reduce to the study of two independent boundary value problems for the Helmholtz equation. We show how to rewrite the Helmholtz equations in the “Hamiltonian form” to express the connection between these two problems explicitly. The problem of finding monochromatic waves in an arbitrary waveguide is reduced to an infinite system of ordinary differential equations in a properly constructed Hilbert space. The calculations are performed in the computer algebra system Sage.
Model of the electromagnetic waves processing in ultrasound
International Nuclear Information System (INIS)
Abrego L, J.; Azorin N, J.; Siles A, S.; Cruz O, A.
2004-01-01
In this work, a model to process the electromagnetic waves in ultrasonic equipment is proposed and it is experimentally demonstrated that, the origin of the ultrasound is electronic and non mechanic. The above mentioned, it has been demonstrated when making in an electronic equipment a spectral analysis the one that indicated an unfolding of the original ultrasonic pulses of 17 K Hz., to 88 K Hz., and of 5 MHz., to 23 GHz. Also, it was obtained the degradation with ultrasound of particles of Hematite and of Galena, as well as the fading of the methylene blue and the generation of an electric current exciting with ultrasound. (Author)
Spectrum of classes of point emitters of electromagnetic wave fields.
Castañeda, Román
2016-09-01
The spectrum of classes of point emitters has been introduced as a numerical tool suitable for the design, analysis, and synthesis of non-paraxial optical fields in arbitrary states of spatial coherence. In this paper, the polarization state of planar electromagnetic wave fields is included in the spectrum of classes, thus increasing its modeling capabilities. In this context, optical processing is realized as a filtering on the spectrum of classes of point emitters, performed by the complex degree of spatial coherence and the two-point correlation of polarization, which could be implemented dynamically by using programmable optical devices.
Scattering of Electromagnetic Waves by Drift Vortex in Plasma
International Nuclear Information System (INIS)
Wang Dong; Chen Yinhua; Wang Ge
2008-01-01
In a quasi-two-dimensional model, the scattering of incident ordinary electromagnetic waves by a dipole-electrostatic drift vortex is studied with first-order Born approximation. The distribution of the scattering cross-section and total cross-section are evaluated analytically in different approximate conditions, and the physical interpretations are discussed. When the wavelength of incident wave is much longer than the vortex radius (k i a || 1), it is found that the angle at which the scattering cross-section reaches its maxim depends significantly on the approximation of the parameters of the vortex used. It is also found that the total scattering cross-section has an affinitive relation with the parameters of the plasma, while it is irrelevant to the frequency of the incident wave in a wide range of parameters of the vortex. In a totally different range of parameters when incident wave is in the radar-frequency range (then k i a || 1, the wavelength of incident wave is much shorter than the vortex radius), the numerical procedure is conducted with computer in order to obtain the distribution and the total expression of the scattering cross-section. Then it is found that the total scattering cross-section in the low frequency range is much larger than that in high frequency range, so the scattering is more effective in the low frequency range than in high frequency range.
International Nuclear Information System (INIS)
Hu, Y.D.; Fraser, B.J.; Olson, J.V.
1990-01-01
In this report, the authors consider the amplification of electromagnetic ion cyclotron waves along a geomagnetic field line in the multicomponent magnetosphere, assuming that the waves propagate parallel to the background magnetic field. The find it is possible for the ring-current protons (energy ∼ 10-100 keV), which supply the free energy to stimulate the waves, to resonate with the waves not only in the equatorial region but also off the equator. An instability, caused by a thermal anisotropy, may occur in separated regions on and/or off the equator. The positions of the source regions along the wave path depend on the concentration of cold heavy ion species. The significant off-equator source regions may be located at geomagnetic latitudes where the waves, with frequencies greater than the He + gyrofrequency on the equator, are in a local He + pass band
Carcione, José M
2014-01-01
Authored by the internationally renowned José M. Carcione, Wave Fields in Real Media: Wave Propagation in Anisotropic, Anelastic, Porous and Electromagnetic Media examines the differences between an ideal and a real description of wave propagation, starting with the introduction of relevant stress-strain relations. The combination of this relation and the equations of momentum conservation lead to the equation of motion. The differential formulation is written in terms of memory variables, and Biot's theory is used to describe wave propagation in porous media. For each rheology, a plane-wave analysis is performed in order to understand the physics of wave propagation. This book contains a review of the main direct numerical methods for solving the equation of motion in the time and space domains. The emphasis is on geophysical applications for seismic exploration, but researchers in the fields of earthquake seismology, rock acoustics, and material science - including many branches of acoustics of fluids and ...
A velocity-amplified electromagnetic energy harvester for small amplitude vibration
Klein, J.; Zuo, L.
2017-09-01
Dedicated, self-powered wireless sensors are widely being studied for use throughout many industries to monitor everyday operations, maintain safety, and report performance characteristics. To enable sensors to power themselves, harvesting energy from machine vibration has been studied, however, its overall effectiveness can be hampered due to small vibration amplitudes and thus limited harvestable energy density. This paper addresses the issue by proposing a novel vibration energy harvester architecture in which a compliant mechanism and proof mass system is used to amplify the vibrational velocity of machine vibration for a linear electromagnetic generator. A prototype has been fabricated and experimentally characterized to verify its effectiveness. When operating at its natural frequency in a low base amplitude, 0.001 inch (25.4 μm) at 19.4 Hz, during lab tests, the harvester has been shown to produce up to 0.91 V AC open voltage, and a maximum power of 2 mW, amplifying the relative proof mass velocity by approximately 5.4 times. This method of locally increasing the machine vibrational velocity has been shown to be a viable option for increasing the potential power output of an energy harvester. In addition, a mathematical model is created based on pseudo-rigid-body dynamics and the analysis matches closely with experiments.
Parametric decay of an extraordinary electromagnetic wave in relativistic plasma
Energy Technology Data Exchange (ETDEWEB)
Dorofeenko, V. G. [Institute for Advanced Studies (Austria); Krasovitskiy, V. B., E-mail: krasovit@mail.ru [Keldysh Institute of Applied Mathematics (Russian Federation); Turikov, V. A. [Peoples’ Friendship University of Russia (Russian Federation)
2015-03-15
Parametric instability of an extraordinary electromagnetic wave in plasma preheated to a relativistic temperature is considered. A set of self-similar nonlinear differential equations taking into account the electron “thermal” mass is derived and investigated. Small perturbations of the parameters of the heated plasma are analyzed in the linear approximation by using the dispersion relation determining the phase velocities of the fast and slow extraordinary waves. In contrast to cold plasma, the evanescence zone in the frequency range above the electron upper hybrid frequency vanishes and the asymptotes of both branches converge. Theoretical analysis of the set of nonlinear equations shows that the growth rate of decay instability increases with increasing initial temperature of plasma electrons. This result is qualitatively confirmed by numerical simulations of plasma heating by a laser pulse injected from vacuum.
Electromagnetic waves in complex systems selected theoretical and applied problems
Velychko, Lyudmyla
2016-01-01
This book gives guidance to solve problems in electromagnetics, providing both examples of solving serious research problems as well as the original results to encourage further investigations. The book contains seven chapters on various aspects of resonant wave scattering, each solving one original problem. All of them are unified by the authors’ desire to show advantages of rigorous approaches at all stages, from the formulation of a problem and the selection of a method to the interpretation of results. The book reveals a range of problems associated with wave propagation and scattering in natural and artificial environments or with the design of antennas elements. The authors invoke both theoretical (analytical and numerical) and experimental techniques for handling the problems. Attention is given to mathematical simulations, computational efficiency, and physical interpretation of the experimental results. The book is written for students, graduate students and young researchers. .
High-efficiency passive full wave rectification for electromagnetic harvesters
Yilmaz, Mehmet; Tunkar, Bassam A.; Park, Sangtak; Elrayes, Karim; Mahmoud, Mohamed A. E.; Abdel-Rahman, Eihab; Yavuz, Mustafa
2014-10-01
We compare the performance of four types of full-wave bridge rectifiers designed for electromagnetic energy harvesters based on silicon diodes, Schottky diodes, passive MOSFETs, and active MOSFETs. Simulation and experimental results show that MOSFET-type rectifiers are more efficient than diode-type rectifiers, reaching voltage and power efficiency of 99% for ideal voltage source with input amplitudes larger than 800 mV. Since active MOSFETs require extra components and an external DC power supply, we conclude that passive MOSFETs are superior for micro-power energy harvesting systems. We demonstrate passive MOSFET rectifiers implemented using discrete, off-shelf components and show that they outperform all electromagnetic harvester rectifiers hitherto reported obtaining a power efficiency of 95%. Furthermore, we show that passive MOSFET rectifiers do not affect the center frequency, harvesting bandwidth, or optimal resistance of electromagnetic harvesters. We demonstrate a complete power management module by adding a capacitor to the rectifier output terminal. We found that this configuration changed the optimal resistive load from 40 Ω to 55 Ω and decreased output power efficiency to 86%.
Pump-dump iterative squeezing of vibrational wave packets.
Chang, Bo Y; Sola, Ignacio R
2005-12-22
The free motion of a nonstationary vibrational wave packet in an electronic potential is a source of interesting quantum properties. In this work we propose an iterative scheme that allows continuous stretching and squeezing of a wave packet in the ground or in an excited electronic state, by switching the wave function between both potentials with pi pulses at certain times. Using a simple model of displaced harmonic oscillators and delta pulses, we derive the analytical solution and the conditions for its possible implementation and optimization in different molecules and electronic states. We show that the main constraining parameter is the pulse bandwidth. Although in principle the degree of squeezing (or stretching) is not bounded, the physical resources increase quadratically with the number of iterations, while the achieved squeezing only increases linearly.
Shoji, M.; Omura, Y.; Grison, B.; Pickett, J. S.; Dandouras, I. S.; Engebretson, M. J.
2011-12-01
Electromagnetic ion cyclotron (EMIC) triggered emissions with rising tones between the H+ and He+ cyclotron frequencies were found in the inner magnetosphere by the recent Cluster observations. Another type of EMIC wave with a constant frequency is occasionally observed below the He+ cyclotron frequency after the multiple EMIC triggered emissions. We performed a self-consistent hybrid simulation with a one-dimensional cylindrical magnetic flux model approximating the dipole magnetic field of the Earth's inner magnetosphere. In the presence of energetic protons with a sufficient density and temperature anisotropy, multiple EMIC triggered emissions are reproduced due to the nonlinear wave growth mechanism of rising-tone chorus emissions, and a constant frequency wave in the He+ EMIC branch is subsequently generated. Through interaction with the multiple EMIC rising-tone emissions, the velocity distribution function of the energetic protons is strongly modified. Because of the pitch angle scattering of the protons, the gradient of the distribution in velocity phase space is enhanced along the diffusion curve of the He+ branch wave, resulting in the linear growth of the EMIC wave in the He+ branch.
Electromagnetic interactions in relativistic infinite component wave equations
International Nuclear Information System (INIS)
Gerry, C.C.
1979-01-01
The electromagnetic interactions of a composite system described by relativistic infinite-component wave equations are considered. The noncompact group SO(4,2) is taken as the dynamical group of the systems, and its unitary irreducible representations, which are infinite dimensional, are used to find the energy spectra and to specify the states of the systems. First the interaction mechanism is examined in the nonrelativistic SO(4,2) formulation of the hydrogen atom as a heuristic guide. A way of making a minimal relativistic generalization of the minimal ineractions in the nonrelativistic equation for the hydrogen atom is proposed. In order to calculate the effects of the relativistic minimal interactions, a covariant perturbation theory suitable for infinite-component wave equations, which is an algebraic and relativistic version of the Rayleigh-Schroedinger perturbation theory, is developed. The electric and magnetic polarizabilities for the ground state of the hydrogen atom are calculated. The results have the correct nonrelativistic limits. Next, the relativistic cross section of photon absorption by the atom is evaluated. A relativistic expression for the cross section of light scattering corresponding to the seagull diagram is derived. The Born amplitude is combusted and the role of spacelike solutions is discussed. Finally, internal electromagnetic interactions that give rise to the fine structure splittings, the Lamb shifts and the hyperfine splittings are considered. The spin effects are introduced by extending the dynamical group
Excitation of planetary electromagnetic waves in the inhomogeneous ionosphere
Directory of Open Access Journals (Sweden)
Yu. Rapoport
2014-04-01
Full Text Available In this paper we develop a new method for the analysis of excitation and propagation of planetary electromagnetic waves (PEMW in the ionosphere of the Earth. The nonlinear system of equations for PEMW, valid for any height, from D to F regions, including intermediate altitudes between D and E and between E and F regions, is derived. In particular, we have found the system of nonlinear one-fluid MHD equations in the β-plane approximation valid for the ionospheric F region (Aburjania et al., 2003a, 2005. The series expansion in a "small" (relative to the local geomagnetic field non-stationary magnetic field has been applied only at the last step of the derivation of the equations. The small mechanical vertical displacement of the media is taken into account. We have shown that obtained equations can be reduced to the well-known system with Larichev–Reznik vortex solution in the equatorial region (see e.g. Aburjania et al., 2002. The excitation of planetary electromagnetic waves by different initial perturbations has been investigated numerically. Some means for the PEMW detection and data processing are discussed.
Shaping electromagnetic waves using software-automatically-designed metasurfaces.
Zhang, Qian; Wan, Xiang; Liu, Shuo; Yuan Yin, Jia; Zhang, Lei; Jun Cui, Tie
2017-06-15
We present a fully digital procedure of designing reflective coding metasurfaces to shape reflected electromagnetic waves. The design procedure is completely automatic, controlled by a personal computer. In details, the macro coding units of metasurface are automatically divided into several types (e.g. two types for 1-bit coding, four types for 2-bit coding, etc.), and each type of the macro coding units is formed by discretely random arrangement of micro coding units. By combining an optimization algorithm and commercial electromagnetic software, the digital patterns of the macro coding units are optimized to possess constant phase difference for the reflected waves. The apertures of the designed reflective metasurfaces are formed by arranging the macro coding units with certain coding sequence. To experimentally verify the performance, a coding metasurface is fabricated by automatically designing two digital 1-bit unit cells, which are arranged in array to constitute a periodic coding metasurface to generate the required four-beam radiations with specific directions. Two complicated functional metasurfaces with circularly- and elliptically-shaped radiation beams are realized by automatically designing 4-bit macro coding units, showing excellent performance of the automatic designs by software. The proposed method provides a smart tool to realize various functional devices and systems automatically.
Nondestructive evaluation of green wood using stress wave and transverse vibration techniques
Udaya B. Halabe; Gangadhar M. Bidigalu; Hota V.S. GangaRao; Robert J. Ross
1997-01-01
Longitudinal stress wave and transverse vibration nondestructive testing (NDT) techniques have proven to be accurate means of evaluating the quality of wood based products. Researchers have found strong relationships between stress wave and transverse vibration parameters (e.g., wave velocity and modulus of elasticity predicted using NDT measurements) with the actual...
Stimulated scattering of electromagnetic waves by magnetosonic modes in a plasma
International Nuclear Information System (INIS)
Stenflo, L.
1985-01-01
The dispersion relation for magnetosonic waves in a dissipative plasma, which is penetrated by a high-frequency electromagnetic wave, is derived. Previous results are generalized and discussed. (author)
International Nuclear Information System (INIS)
Leyser, T.B.
1994-01-01
A nonlinear dispersion relation for the parametric decay of an electrostatic upper hybrid wave into an ordinary mode electromagnetic wave, propagating parallel to the ambient magnetic field, and an electrostatic low frequency wave, being either a lower hybrid wave or a high harmonic ion Bernstein wave, is derived. The coherent and resonant wave interaction is considered to take place in a weakly magnetized and collisionless Vlasov plasma. The instability growth rate is computed for parameter values typical of ionospheric modification experiments, in which a powerful high frequency electromagnetic pump wave is injected into the ionospheric F-region from ground-based transmitters. The electromagnetic radiation which is excited by the decaying upper hybrid wave is found to be consistent with the prominent and commonly observed downshifted maximum (DM) emission in the spectrum of stimulated electromagnetic emission
Terahertz wave manipulation based on multi-bit coding artificial electromagnetic surfaces
Li, Jiu-Sheng; Zhao, Ze-Jiang; Yao, Jian-Quan
2018-05-01
A polarization insensitive multi-bit coding artificial electromagnetic surface is proposed for terahertz wave manipulation. The coding artificial electromagnetic surfaces composed of four-arrow-shaped particles with certain coding sequences can generate multi-bit coding in the terahertz frequencies and manipulate the reflected terahertz waves to the numerous directions by using of different coding distributions. Furthermore, we demonstrate that our coding artificial electromagnetic surfaces have strong abilities to reduce the radar cross section with polarization insensitive for TE and TM incident terahertz waves as well as linear-polarized and circular-polarized terahertz waves. This work offers an effectively strategy to realize more powerful manipulation of terahertz wave.
Development of a Ferrite-Based Electromagnetic Wave Detector
Directory of Open Access Journals (Sweden)
Muhammad Hanish Zakariah
2017-11-01
Full Text Available Direct detection of hydrocarbon by an active source using electromagnetic (EM wave termed Sea Bed Logging (SBL has shown very promising results. However, currently available electromagnetic wave technology has a number of challenges including sensitivity and lapsed time. Our initial response to this issue is to develop a ferrite-based EM wave detector for Sea Bed Logging (SBL. Ferrite bar and copper rings in various diameters were used as detector 1 (D1. For Detector 2 (D2, toroid added with copper wires in different lengths at the centre of it were used. The first experiment is to determine the inductance and resistance for both detectors by using LCR meter. We obtained the highest inductance value of 0.02530 mH at the ferrite bar when it was paired with a 15 cm diameter copper ring and 0.00526 mH for D2 using a 100 cm copper wire placed at the centre of the toroid. The highest resistivity for D1 was measured at ferrite bar paired with a 15 cm diameter copper ring and 1.099 Ω when using 20 cm length of copper wire. The second interest deals with voltage peak-to-peak (Vp-p value for both detectors by using oscilloscope. The highest voltage value at the ferrite bar of D1 was 25.30 mV. While at D2, the highest voltage measured was 27.70 mV when using a 100 cm copper wire. The third premise is the comparison of sensitivity and lapsed time for both detectors. It was found that D1 was 61% more sensitive than D2 but had higher lapsed time than D2.
Whistler Observations on DEMETER Compared with Full Electromagnetic Wave Simulations
Compston, A. J.; Cohen, M.; Lehtinen, N. G.; Inan, U.; Linscott, I.; Said, R.; Parrot, M.
2014-12-01
Terrestrial Very Low Frequency (VLF) electromagnetic radiation, which strongly impacts the Van Allen radiation belt electron dynamics, is injected across the ionosphere into the Earth's plasmasphere from two primary sources: man-made VLF transmitters and lightning discharges. Numerical models of trans-ionospheric propagation of such waves remain unvalidated, and early models may have overestimated the absorption, hindering a comprehensive understanding of the global impact of VLF waves in the loss of radiation belt electrons. In an attempt to remedy the problem of a lack of accurate trans-ionospheric propagation models, we have used a full electromagnetic wave method (FWM) numerical code to simulate the propagation of lightning-generated whistlers into the magnetosphere and compared the results with whistlers observed on the DEMETER satellite and paired with lightning stroke data from the National Lightning Detection Network (NLDN). We have identified over 20,000 whistlers occuring in 14 different passes of DEMETER over the central United States during the summer of 2009, and 14,000 of those occured within the 2000 km x 2000 km simulation grid we used. As shown in the attached figure, which shows a histogram of the ratio of the simulated whistler energy to the measured whistler energy for the 14,000 whistlers we compared, the simulation tends to slightly underestimate the total whistler energy injected by about 5 dB. However, the simulation underestimates the DEMETER measurements more as one gets further from the source lightning stroke, so since the signal to noise ratio of more distant whistlers will be smaller, possibly additive noise in the DEMETER measurements (which of course is not accounted for in the model) may explain some of the observed discrepancy.
International Nuclear Information System (INIS)
Siddique, Abu Raihan Mohammad; Mahmud, Shohel; Van Heyst, Bill
2017-01-01
Highlights: • A T-shaped cantilever type electromagnetic vibration based MPG has been described. • The designed EVMPG is useful for low frequency based vibration sources. • Both experimental tests and theoretical analysis have been performed. • The final compact prototype was tested at different conditions of human movements. • The prototype can generate 35.2 mV and 0.22 mW at 7 Hz with 5.6 Ω. - Abstract: The design, development, and analyses of low-frequency vibration based T-shaped cantilever type electromagnetic micro power generators (EVMPGs) are presented in this paper. Four different configurations (Configurations A to D) of EVMPGs were designed and fabricated and subsequently characterized using detailed experimental and limited analytical techniques. Configuration A and B consisted of a single and a double cylindrical moving magnets (NdFeB), respectively, while Configuration C consisted of four rectangular moving magnets with respect to a fixed copper coil. In contrast, Configuration D used a moving coil between four rectangular magnets with a back-iron bar. The open circuit RMS voltage output was observed to be a maximum from Configuration D (98.2 mV at 6.29 Hz) with a base vibration acceleration of 0.8 m s"−"2. Therefore, Configuration D was selected for further experimental investigations, which included changing the back-iron bar thickness, changing the base acceleration level, and changing the air gap separation between the magnets in order to optimize this configuration. The maximum load RMS voltage and power outputs of Configuration D were 105.4 mV and 1.35 mW at 6.29 Hz for load resistance 8.2 Ω and a base acceleration of 0.8 m s"−"2 with a 4.2 mm back-iron bar when the air gap between the magnets was 20 mm. Finally, a small portable EVMPG prototype was developed based on the Configuration D and was tested at different human movement conditions (i.e., walking, quick walking, and running). The developed EVMPG prototype was capable of
Ionospheric electron acceleration by electromagnetic waves near regions of plasma resonances
International Nuclear Information System (INIS)
Villalon, E.
1989-01-01
Electron acceleration by electromagnetic fields propagating in the inhomogeneous ionospheric plasma is investigated. It is found that high-amplitude short wavelength electrostatic waves are generated by the incident electromagnetic fields that penetrate the radio window. These waves can very efficiently transfer their energy to the electrons if the incident frequency is near the second harmonic of the cyclotron frequency
Adrian, Mark L.; Wendel, D. E.
2011-01-01
We investigate observations of intense bursts of electromagnetic waves in association with magnetic reconnection in the turbulent magnetosheath. These structured, broadband bursts occur above 80-Hz, often displaying features reminiscent of absorption bands and are observed at local minima in the magnetic field. We present detailed analyses of these intense bursts of electromagnetic waves and quantify their proximity to X- and O-nulls.
The modulational and filamentational instabilities of two coupled electromagnetic waves in plasmas
International Nuclear Information System (INIS)
Shukla, P.K.
1992-01-01
The modulational and filamentational instabilities of two coupled electromagnetic waves have been investigated, taking into account the combined effect of relativistic electron mass variations and nonresonant density fluctuations that are driven by the ponderomotive force. The relevance of our investigation to phenomena related with nonlinear mixing of electromagnetic waves is pointed out. (orig.)
O Electromagnetic Power Waves and Power Density Components.
Petzold, Donald Wayne
1980-12-01
On January 10, 1884 Lord Rayleigh presented a paper entitled "On the Transfer of Energy in the Electromagnetic Field" to the Royal Society of London. This paper had been authored by the late Fellow of Trinity College, Cambridge, Professor J. H. Poynting and in it he claimed that there was a general law for the transfer of electromagnetic energy. He argued that associated with each point in space is a quantity, that has since been called the Poynting vector, that is a measure of the rate of energy flow per unit area. His analysis was concerned with the integration of this power density vector at all points over an enclosing surface of a specific volume. The interpretation of this Poynting vector as a true measure of the local power density was viewed with great skepticism unless the vector was integrated over a closed surface, as the development of the concept required. However, within the last decade or so Shadowitz indicates that a number of prominent authors have argued that the criticism of the interpretation of Poynting's vector as a local power density vector is unjustified. The present paper is not concerned with these arguments but instead is concerned with a decomposition of Poynting's power density vector into two and only two components: one vector which has the same direction as Poynting's vector and which is called the forward power density vector, and another vector, directed opposite to the Poynting vector and called the reverse power density vector. These new local forward and reverse power density vectors will be shown to be dependent upon forward and reverse power wave vectors and these vectors in turn will be related to newly defined forward and reverse components of the electric and magnetic fields. The sum of these forward and reverse power density vectors, which is simply the original Poynting vector, is associated with the total electromagnetic energy traveling past the local point. Another vector which is the difference between the forward
Harne, Ryan L
2012-07-01
Conversion of ambient vibrational energy into electric power has been the impetus of much modern research. The traditional analysis has focused on absolute electrical power output from the harvesting devices and efficiency defined as the convertibility of an infinite resource of vibration excitation into power. This perspective has limited extensibility when applying resonant harvesters to host resonant structures when the inertial influence of the harvester is more significant. Instead, this work pursues a fundamental understanding of the coupled dynamics of a main mass-spring-damper system to which an electromagnetic or piezoelectric mass-spring-damper is attached. The governing equations are derived, a metric of efficiency is presented, and analysis is undertaken. It is found that electromagnetic energy harvesting efficiency and maximum power output is limited by the strength of the coupling such that no split system resonances are induced for a given mass ratio. For piezoelectric harvesters, only the coupling strength and certain design requirements dictate maximum power and efficiency achievable. Since the harvesting circuitry must "follow" the split resonances as the piezoelectric harvesters become more massive, the optimum design of piezoelectric harvesters appears to be more involved than for electromagnetic devices.
Electromagnetic waves near the proton cyclotron frequency: Stereo observations
Energy Technology Data Exchange (ETDEWEB)
Jian, L. K. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Wei, H. Y.; Russell, C. T. [Institute of Geophysics and Planetary Physics, University of California, Los Angeles, CA 90095 (United States); Luhmann, J. G. [Space Science Laboratory, University of California, Berkeley, CA 94720 (United States); Klecker, B. [Max-Planck-Institut für Extraterrestrische Physik, D-85741 Garching (Germany); Omidi, N. [Solana Scientific Inc., Solana Beach, CA 92075 (United States); Isenberg, P. A. [Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, Durham, NH 03824 (United States); Goldstein, M. L.; Figueroa-Viñas, A. [Heliophysics Science Division, NASA Goddard Space Flight Center, MD 20771 (United States); Blanco-Cano, X., E-mail: lan.jian@nasa.gov [Instituto de Geofisica, Universidad Nacional Autónoma de México, Coyoacán D.F. (Mexico)
2014-05-10
Transverse, near-circularly polarized, parallel-propagating electromagnetic waves around the proton cyclotron frequency were found sporadically in the solar wind throughout the inner heliosphere. They could play an important role in heating and accelerating the solar wind. These low-frequency waves (LFWs) are intermittent but often occur in prolonged bursts lasting over 10 minutes, named 'LFW storms'. Through a comprehensive survey of them from Solar Terrestrial Relations Observatory A using dynamic spectral wave analysis, we have identified 241 LFW storms in 2008, present 0.9% of the time. They are left-hand (LH) or right-hand (RH) polarized in the spacecraft frame with similar characteristics, probably due to Doppler shift of the same type of waves or waves of intrinsically different polarities. In rare cases, the opposite polarities are observed closely in time or even simultaneously. Having ruled out interplanetary coronal mass ejections, shocks, energetic particles, comets, planets, and interstellar ions as LFW sources, we discuss the remaining generation scenarios: LH ion cyclotron instability driven by greater perpendicular temperature than parallel temperature or by ring-beam distribution, and RH ion fire hose instability driven by inverse temperature anisotropy or by cool ion beams. The investigation of solar wind conditions is compromised by the bias of the one-dimensional Maxwellian fit used for plasma data calibration. However, the LFW storms are preferentially detected in rarefaction regions following fast winds and when the magnetic field is radial. This preference may be related to the ion cyclotron anisotropy instability in fast wind and the minimum in damping along the radial field.
Electromagnetic Components of Auroral Hiss and Lower Hybrid Waves in the Polar Magnetosphere
Wong, H. K.
1995-01-01
DE-1 has frequently observed waves in the whistler and lower hybrid frequencies range. Besides the electrostatic components, these waves also exhibit electromagnetic components. It is generally believed that these waves are excited by the electron acoustic instability and the electron-beam-driven lower hybrid instability. Because the electron acoustic and the lower hybrid waves are predominately electrostatic waves, they cannot account for the observed electromagnetic components. In this work, it is suggested that these electromagnetic components can be explained by waves that are generated near the resonance cone and that propagate away from the source. The role that these electromagnetic waves can play in particle acceleration processes at low altitude is discussed.
Relativistic harmonic content of nonlinear electromagnetic waves in underdense plasmas
International Nuclear Information System (INIS)
Mori, W.B.; Decker, C.D.; Leemans, W.P.
1993-01-01
The relativistic harmonic content of large amplitude electromagnetic waves propagating in underdense plasmas is investigated. The steady state harmonic content of nonlinear linearly polarized waves is calculated for both the very underdense (w p /w o ) much-lt 1 and critical density (w p /w o ) ≅ 1 limits. For weak nonlinearities, eE o /mcw o p /w o . Arguments are given for extending these results for arbitrary wave amplitudes. The authors also show that the use of the variable x-ct and the quasi-static approximation leads to errors in both magnitude and sign when calculating the third harmonic. In the absence of damping or density gradients the third harmonic's amplitude is found to oscillate between zero and twice the steady state value. Preliminary PIC simulation results are presented. The simulation results are in basic agreement with the uniform plasma predictions for the third harmonic amplitude. However, the higher harmonics are orders of magnitude larger than expected and the presence of density ramps significantly modifies the results
Self-modulation and filamentation of electromagnetic waves in a plasma
International Nuclear Information System (INIS)
Bingham, R.; Lashmore-Davies, C.N.
1976-01-01
Self-modulation and filamentation of an electromagnetic wave is considered as a problem of the non-linear interaction between electromagnetic and ion waves. A new electro-magnetic modulational instability is obtained, whose threshold is the same as that of the oscillating two-stream instability. A simple geometrical model is given of filamentation when the non-linearity is due to the ponderomotive force. The relationship between the filamentation and electromagnetic modulational instabilities and other parametric instabilities is considered. In particular, it is shown that both electromagnetic modulational and filamentation instabilities can occur at the critical density where they have the same threshold as the modulational instability of a Langmuir wave. Finally, a conservation relation (a generalization of the Manley-Rowe relation) for the wave action density is obtained for the filamentation instability. This shows clearly that this instability results from a four wave interaction. (author)
Electron Bernstein wave excitation by counterpropagating electromagnetic waves in a plasma
International Nuclear Information System (INIS)
Kumar, Asheel; Tripathi, V.K.
2005-01-01
Two high-power counterpropagating electromagnetic waves (ω 1 ,k 1 x) and (ω 2 ,-k 2 x) in a low-density plasma in the presence of a static magnetic field B s z, drive an electron Bernstein wave at the beat frequency ω=ω 1 -ω 2 and k=(k 1 +k 2 )x, when ω∼ω c 1 ,ω 2 and kρ≥1, where ω c is the electron cyclotron frequency and ρ is the Larmor radius. The electromagnetic waves exert a ponderomotive force on the electrons and resonantly drive the Bernstein mode(ω,k). When the pump waves have finite z extent, the Bernstein wave has an effective k z and a component of group velocity in the direction of the magnetic field, leaking it out of the interaction region, limiting the level of the Bernstein mode. Plasma inhomogeneity also introduces convection losses. However, the electron Bernstein mode potential could still be significantly greater than the ponderomotive potential
Energy Technology Data Exchange (ETDEWEB)
Shiohata, K.; Nemoto, K.; Nagawa, Y.; Sakamoto, S.; Kobayashi, T.; Ito, M.; Koharagi, H. [Hitachi, Ltd, Tokyo (Japan)
1998-11-01
In this analysis method, electromagnetic force calculated by 2-dimensional analysis is transformed into external force for 3-dimensional structural-vibration analysis. And a modeling procedure for a vibrating structure is developed. Further, a space-modal-resonance criteria which relates electromagnetic force to structural-vibration or noise is introduced. In the structural-vibration analysis, the finite element method is used; and in the noise analysis, the boundary element method is used. Finally, vibration and noise of an induction motor are calculated using this criteria. Consequently, high-accuracy modeling is achieved and noise the calculated by the simulation almost coincides with that obtained by experiments. And it is clarified that the-space-modal resonance criteria is effective in numerical simulation. 11 refs., 9 figs., 3 tabs.
Electromagnetically Induced Transparency in Four Wave Mixing Process
International Nuclear Information System (INIS)
Kucukkara, I.
2008-01-01
We have theoretically studied Four Wave Mixing (FWM) process in VUV (Vacuum Ultraviolet) region enhanced by Electromagnetically Induced Transparency in Krypton gas medium at room temperature. One of the mixing fields, in the ultraviolet region at 212.5 nm was in two-photon resonance with the 4p 6 1 S 0 -4p 5 5p[0,1/2] transition of Krypton and the second field (coupling field) at 759 nm was resonant with the 4p 5 5p[0,1/2]-4p 5 5s[1,1/2] transition in scheme. This coupling field produced an electromagnetically induced transparency and thus the efficiency of the generation of the field at 123.6 nm on the 4p 5 5s[1,1/2] to 4p 6 1 S 0 transition is enhanced. We modified the computer program previously written by changing some variables like pressure, interaction region length, UV energy, IR energy. As demonstrated by the intensity generated VUV light versus Krypton pressure graphic, the most efficient intensity value, which was approximately 4.2x10 1 6 arbitrary units, was obtained while IR energy was 3x10 - 4 J and the pressure was 2x10 - 3 bar
Scattering of electromagnetic plane waves by a buried vertical dike
Directory of Open Access Journals (Sweden)
Batista Lurimar S.
2003-01-01
Full Text Available The complete and exact solution of the scattering of a TE mode frequency domain electromagnetic plane wave by a vertical dike under a conductive overburden has been established. An integral representation composed of one-sided Fourier transforms describes the scattered electric field components in each one of the five media: air, overburden, dike, and the country rocks on both sides of the dike. The determination of the terms of the series that represents the spectral components of the Fourier integrals requires the numerical inversion of a sparse matrix, and the method of successive approaches. The zero-order term of the series representation for the spectral components of the overburden, for given values of the electrical and geometrical parameters of the model, has been computed. This result allowed to determine an approximate value of the variation of the electric field on the top of the overburden in the direction perpendicular to the strike of the dike. The results demonstrate the efficiency of this forward electromagnetic modeling, and are fundamental for the interpretation of VLF and Magnetotelluric data.
Electromagnetic Wave Propagation Through the ZR Z-Pinch Accelerator
International Nuclear Information System (INIS)
Rose, D. V.; Welch, D. R.; Madrid, E. A.; Miller, C. L.; Clark, R. E.; Stygar, W. A.; Struve, K.; Corcoran, P. A.; Whitney, B.
2009-01-01
A fully three-dimensional electromagnetic model of the major pulsed power components of the 26-MA ZR accelerator is presented. This large-scale simulation model tracks the evolution of electromagnetic waves through the intermediate storage capacitors, laser-triggered gas switches, pulse-forming lines, water switches, tri-plate transmission lines, and water convolute to the vacuum insulator stack. The plates at the insulator stack are coupled to a transmission line circuit model of the four-level magnetically-insulated transmission line section and post-hole convolutes. The vacuum section circuit model is terminated by either a short-circuit load or dynamic models of imploding z-pinch loads. The simulations results are compared with electrical measurements made throughout the ZR accelerator and good agreement is found, especially for times before and up to peak load power. This modeling effort represents new opportunities for modeling existing and future large-scale pulsed power systems used in a variety of high energy density physics and radiographic applications.
Next wave EM technology : Electromagnetic communication technology continues to progress
International Nuclear Information System (INIS)
Ludwick, J.
1998-01-01
Alpine Oil Services Corp. and Ryan Energy Technologies Inc., have made technological advances in the use of real time electromagnetic (EM) data transmission, using low frequency radio waves to transmit well commands or geological information. The development of the telemetry activated tool was done in two steps. The first technology was real time EM data transmission from the subsurface which used the wellbore to transfer information. The second step was constructing a memory pack which involved an electronic instrument installed in the wellbore which was programmed to perform certain tasks at certain times by transmitting signals back and forth. The use of EM communication allows the geological steering information to come back faster. The EM signal is much faster compared to MWD systems for deeper directional wells. The EM technology also has immediate applications in underbalanced drilling. 1 fig
Design of Metamaterials for control of electromagnetic waves
Koschny, Thomas
2014-03-01
Metamaterials are artificial effective media supporting propagating waves that derive their properties form the average response of deliberately designed and arranged, usually resonant scatterers with structural length-scales much smaller than the wavelength inside the material. Electromagnetic metamaterials are the most important implementation of metamaterials, which are made from deeply sub-wavelength electric, magnetic and chiral resonators and can be designed to work from radio frequencies all the way to visible light. Metamaterials have been major new development in physics and materials science over the last decade and are still attracting more interest as they enable us to create materials with unique properties like negative refraction, flat and super lenses, impedance matching eliminating reflection, perfect absorbers, deeply sub-wavelength sized wave guides and cavities, tunability, enhanced non-linearity and gain, chirality and huge optical activity, control of Casimir forces, and spontaneous emission, etc. In this talk, I will discuss the design, numerical simulation, and mathematical modeling of metamaterials. I will survey the current state of the art and discuss challenges, possible solutions and perspectives. In particular, the problem of dissipative loss and their possible compensation by incorporating spatially distributed gain in metamaterials. If the gain sub-system is strongly coupled to the sub-wavelength resonators of the metamaterial loss compensation and undamping of the resonant response of the metamaterials can occur. I will explore new, alternative dielectric low loss resonators for metamaterials as well as the potential of new conducting materials such as Graphene to replace metals as the conducting material in resonant metamaterials. Two dimensional metamaterials or metasurfaces, implementations of effective electromagnetic current sheets in which both electric and magnetic sheet conductivities are controlled by the average response
Nonlinear propagation of intense electromagnetic waves in weakly-ionized plasmas
International Nuclear Information System (INIS)
Shukla, P.K.
1993-01-01
The nonlinear propagation of intense electromagnetic waves in weakly-ionized plasmas is considered. Stimulated scattering mechanisms involving electromagnetic and acoustic waves in an unmagnetized plasma are investigated. The growth rate and threshold for three-wave decay interactions as well as modulational and filamentation instabilities are presented. Furthermore, the electromagnetic wave modulation theory is generalized for weakly ionized collisional magnetoplasmas. Here, the radiation envelope is generally governed by a nonlinear Schroedinger equation. Accounting for the dependence of the attachment frequency on the radiation intensity, ponderomotive force, as well as the differential Joule heating nonlinearity, the authors derive the equations for the nonthermal electron density and temperature perturbations. The various nonlinear terms in the electron motion are compared. The problems of self-focusing and wave localization are discussed. The relevance of the investigation to ionospheric modification by powerful electromagnetic waves is pointed out
Conversion of electromagnetic to gravitational waves in the Reissner-Nordstroem spacetime
International Nuclear Information System (INIS)
Crispino, Luis C.B.; Oliveira, Ednilton S.; Higuchi, Atsushi
2011-01-01
Full text: Wave scattering by black holes is a subject that has received much attention in the 1970s, and has been extensively studied since then. Some recent works have been devoted to computing the scalar absorption and scattering cross sections of charged black holes. The presence of a background electromagnetic field leads to a coupling between electromagnetic and gravitational perturbations. To study the propagation of the electromagnetic field in Reissner-Nordstroem spacetime, one has to take into account this electromagnetic-gravitational mixing. In this work we compute numerically the absorption cross section of Reissner-Nordstroem black holes for the electromagnetic field for arbitrary frequencies, taking into account the coupling of the electromagnetic and gravitational perturbations. We also compute the conversion coefficients of electromagnetic to gravitational waves by scattering from a Reissner-Nordstroem black hole. (author)
International Nuclear Information System (INIS)
Sakai, J.I.; Haruki, T.; Kazimura, Y.
2000-01-01
It is shown by using a 2-D fully relativistic electromagnetic particle-in-cell (PIC) code that the tearing instability in a current sheet of pair plasmas is caused by Landau resonances of both electrons and positrons. Strong magnetic flux can be generated during coalescence of magnetic islands in the nonlinear phase of the tearing instability. The magnetic flux produced in an O-type magnetic island is caused from the counter-streaming instability found by Kazimura et al. (1998). It is also shown that charge separation with a quadrupole-like structure is generated from the localized strong magnetic flux. During the decay of the quadrupole-like charge structure as well as the magnetic flux, there appear wave emission with high-frequency electromagnetic waves and Alfven waves as well as Langmuir waves. We also show by using a 3-D PIC code that current filaments associated with the O-type magnetic islands become unstable against the kink instability during the coalescence of current filaments. (orig.)
Interaction of High Intensity Electromagnetic Waves with Plasmas: Final Report
International Nuclear Information System (INIS)
Shvets, G.
2008-01-01
The focus of our work during the duration of this grant was on the following areas: (a) the fundamental plasma physics of intense laser-plasma interactions, including the nonlinear excitation of plasma waves for accelerator applications, as well as the recently discovered by us phenomenon of the relativistic bi-stability of relativistic plasma waves driven by a laser beatwave; (b) interaction of high power microwave beams with magnetized plasma, including some of the recently discovered by us phenomena such as the Undulator Induced Transparency (UIT) as well as the new approaches to dynamic manipulation of microwave pulses; (c) investigations of the multi-color laser pulse interactions in the plasma, including the recently discovered by us phenomenon of Electromagnetic Cascading (EC) and the effect of the EC of three-dimensional dynamics of laser pulses (enhanced/suppressed selffocusing etc.); (d) interaction of high-current electron beams with the ambient plasma in the context of Fast Ignitor (FI) physics, with the emphasis on the nonlinear dynamics of the Weibel instability and beam filamentation.
Electromagnetic Waves and Bursty Electron Acceleration: Implications from Freja
Andersson, Laila; Ivchenko, N.; Wahlund, J.-E.; Clemmons, J.; Gustavsson, B.; Eliasson, L.
2000-01-01
Dispersive Alfven wave activity is identified in four dayside auroral oval events measured by the Freja satellite. The events are characterized by ion injection, bursty electron precipitation below about I keV, transverse ion heating and broadband extremely low frequency (ELF) emissions below the lower hybrid cutoff frequency (a few kHz). The broadband emissions are observed to become more electrostatic towards higher frequencies. Large-scale density depletions/cavities, as determined by the Langmuir probe measurements, and strong electrostatic emissions are often observed simultaneously. A correlation study has been carried out between the E- and B-field fluctuations below 64 Hz (the dc instrument's upper threshold) and the characteristics of the precipitating electrons. This study revealed that the energization of electrons is indeed related to the broadband ELF emissions and that the electrostatic component plays a predominant role during very active magnetospheric conditions. Furthermore, the effect of the ELF electromagnetic emissions on the larger scale field-aligned current systems has been investigated, and it is found that such an effect cannot be detected. Instead, the Alfvenic activity creates a local region of field-aligned currents. It is suggested that dispersive Alfven waves set up these local field-aligned current regions and in turn trigger more electrostatic emissions during certain conditions. In these regions ions are transversely heated, and large-scale density depletions/cavities may be created during especially active periods.
Cellular and molecular effects of electromagnetic radiation and sonic waves
Directory of Open Access Journals (Sweden)
Patricia Froes Meyer
2013-07-01
Full Text Available Electromagnetic radiation (in the form of pulsed magnetic fields, radiofrequency and intense pulsed light and mechanical agents (such as sonic waves have been used in physical therapy. The aim of this study was to assess the effects of low-intensity magnetic fields, sonic and radiofrequency waves, and intense pulsed light on the survival of Escherichia coli cultures and on the electrophoretic mobility of plasmid DNA. Exponentially growing E. coli AB1157 cultures and plasmid DNA samples were exposed to these physical agents and 0.9% NaCl (negative control and SnCl2 (positive control solutions. Aliquots of the cultures were diluted and spread onto a solidified rich medium. The colony-forming units were counted after overnight incubation and the survival fraction was calculated. Agarose gel electrophoresis was performed to visualise and quantify the plasmid topological forms. The results suggest that these agents do not alter the survival of E. coli cells or plasmid DNA electrophoresis mobility. Moreover, they do not protect against the lesive action of SnCl2. These physical agents therefore had no cytotoxic or genotoxic effects under the conditions studied.
Spontaneous generation of electromagnetic waves in plasmas with electron thermal flux
International Nuclear Information System (INIS)
Okada, Toshio
1977-01-01
Spontaneous generation of propagating electromagnetic fields due to a microinstability is investigated for plasmas which convey electron thermal fluxes. The following two cases are examined: 1) Electromagnetic fields spontaneously excited by electrons in a velocity distribution of skewed Maxwellian type. 2) Electromagnetic waves generated by electrons in a velocity distribution which consists of a main part and a high energy part. In this case, the electron thermal flux can be very high. In both cases, induced electromagnetic waves with relatively low frequencies propagate parallel to the direction of Thermal flux. (auth.)
International Nuclear Information System (INIS)
Dragila, R.; Vukovic, S.
1988-01-01
The properties of surfave waves that are associated with a boundary between a rare plasma and a dense magnetoactive plasma and that propagate along a dc magnetic field are investigated. It is shown that the presence of the magnetic field introduces symmetry in terms of the polarization of the incident electromagnetic wave that excites the surface waves. A surface wave excited by an incident p-polarized (s-polarized) electromagnetic wave leaks in the form of an s-polarized (p-polarized) electromagnetic wave. The rate of rotation of polarization is independent of the polarization of the incident wave. Because a surface wave can leak in the form of an s-polarized electromagnetic wave, it can also be pumped by such a wave, and conditions were found for excitation of a surface wave by an s-polarized incident electromagnetic wave
Risk perception and public concerns of electromagnetic waves from cellular phones in Korea.
Kim, Kyunghee; Kim, Hae-Joon; Song, Dae Jong; Cho, Yong Min; Choi, Jae Wook
2014-05-01
In this study, the difference between the risk perception of electromagnetic waves from cellular phones and the risk perception of other factors such as environment and food was analyzed. The cause of the difference in the psychological and social factors that affect the group with high risk perception of electromagnetic waves was also analyzed. A questionnaire survey on the risk perception of electromagnetic waves from cellular phones was carried out on 1001 subjects (men and women) over the age of 20. In the group with high risk perception of electromagnetic waves from cellular phones, women had higher risk perception than men. Logistic regression analysis, where the group with high risk perception of electromagnetic waves and the group with low risk perception were used as dependent variables, indicated that the risk perception of electromagnetic waves in women was 1.815 times statistically significantly higher than the risk perception of men (95% CI: 1.340-2.457). Also, high risk perception of electromagnetic waves from cellular phones was observed when the subjects considered that they had more personal knowledge (OR: 1.416, 95% CI: 1.216-1.648), that the seriousness of the risk to future generations was high (OR: 1.410, 95% CI: 1.234-1.611), and their outrage for the occurrence of accidents related to electromagnetic waves was high (OR: 1.460, 95% CI: 1.264-1.686). The results of this study need to be sufficiently considered and reflected in designing the risk communication strategies and communication methods for the preventive measures and advice on electromagnetic waves from cellular phones. © 2014 Wiley Periodicals, Inc.
Growth Retardation of Chick Embryo Exposed to a Low Dose of Electromagnetic Waves
International Nuclear Information System (INIS)
Siddiqi, N.; Norrish, M.; Heming, T.
2016-01-01
Background: The objectives of this study were to explore the effects of low dose of the non-ionizing (REW) emitted by a mobile phone on the development of chick embryo. Methods: one hundred and twenty chick fertilized eggs were equally divided into a control and an exposed group. Sixty fertilized eggs were placed in an egg incubator with a mobile phone (SAR US: 1.10W/kg (head) 0.47 W/kg body) in silent mode having vibration disable mode. Mobile was called for a total of 20 minutes in 24 hours. Twenty embryos each were sacrificed at day 5, 10 and 15, mortality, wet body weight, head to rump length, eye diameter and morphological changes were noted. The control group, 60 eggs were incubated in the same conditions, having removed the phone. Results: No mortality was noted. The experimental group exposed to REW showed subcutaneous haemorrhagic areas and significant growth retardation at day 10 as evidence by smaller eye diameter, wet weight and CR length than the control group. There were no significant growth differences at either day 5 or at day 15. Conclusion: Electromagnetic waves emitted from mobile phones even though for a very short duration of 20 minutes per day have affected the growth of the chick embryo at day 10 of incubation, Hence exposure of these waves are not 100 percent safe. (author)
Growth Retardation Of Chick Embryo Exposed To A Low Dose Of Electromagnetic Waves.
Siddiqi, Najam; John C, Muthusami; Norrish, Mark; Heming, Thomas
2016-01-01
The objectives of this study were to explore the effects of low dose of the nonionizing (REW) emitted by a mobile phone on the development of chick embryo. one hundred and twenty chick fertilized eggs were equally divided into a control and an exposed group. Sixty fertilized eggs were placed in an egg incubator with a mobile phone (SAR US: 1.10W/kg (head) 0.47 W/kg body) in silent mode having vibration disable mode. Mobile was called for a total of 20 minutes in 24 hours. Twenty embryos each were sacrificed at day 5, 10 and 15, mortality, wet body weight, head to rump length, eye diameter and morphological changes were noted. The control group, 60 eggs were incubated in the same conditions, having removed the phone. No mortality was noted. The experimental group exposed to REW showed subcutaneous haemorrhagic areas and significant growth retardation at day 10 as evidence by smaller eye diameter, wet weight and CR length than the control group. There were no significant growth differences at either day 5 or at day 15. Electromagnetic waves emitted from mobile phones even though for a very short duration of 20 minutes per day have affected the growth of the chick embryo at day 10 of incubation, Hence exposure of these waves are not 100% safe.
International Nuclear Information System (INIS)
Bell, T.F.; Ngo, H.D.
1990-01-01
Recent satellite observations demonstrate that high amplitude, short wavelength (5 m ≤ λ ≤ 100 m) electrostatic waves are commonly excited by electromagnetic whistler mode waves propagating in regions of the magnetosphere and topside ionosphere where small-scale magnetic-field-aligned plasma density irregularities are thought to exist. A new theoretical model of this phenomenon is presented, based upon passive linear scattering in a cold magnetoplasma. In this model the electrostatic waves are excited by linear mode coupling as the incident electromagnetic whistler mode waves scatter from the magnetic-field-aligned plasma density irregularities. The excited short wavelength waves are quasi-electrostatic whistler mode waves, a type of lower hybrid wave, whose wave normal lies near the whistler mode resonance cone where the wave refractive index becomes very large. The amplitude of the excited electrostatic lower hybrid waves is calculated for a wide range of values of input electromagnetic wave frequency, wave normal direction, electron plasma frequency, gyrofrequency, ion composition, and irregularity scale and density enhancement. Results indicate that high amplitude lower hybrid waves can be excited over a wide range of parameters for irregularity density enhancements as low as 5% whenever the scale of the irregularity is of the same order as the lower hybrid wavelength
International Nuclear Information System (INIS)
Sugaya, R.; Ue, A.; Maehara, T.; Sugawa, M.
1996-01-01
Acceleration and heating of a relativistic electron beam by cascading nonlinear Landau damping involving three or four intense electromagnetic waves in a plasma are studied theoretically based on kinetic wave equations and transport equations derived from relativistic Vlasov endash Maxwell equations. Three or four electromagnetic waves excite successively two or three nonresonant beat-wave-driven relativistic electron plasma waves with a phase velocity near the speed of light [v p =c(1-γ -2 p ) 1/2 , γ p =ω/ω pe ]. Three beat waves interact nonlinearly with the electron beam and accelerate it to a highly relativistic energy γ p m e c 2 more effectively than by the usual nonlinear Landau damping of two electromagnetic waves. It is proved that the electron beam can be accelerated to more highly relativistic energy in the plasma whose electron density decreases temporally with an appropriate rate because of the temporal increase of γ p . copyright 1996 American Institute of Physics
Variational structure of inverse problems in wave propagation and vibration
Energy Technology Data Exchange (ETDEWEB)
Berryman, J.G.
1995-03-01
Practical algorithms for solving realistic inverse problems may often be viewed as problems in nonlinear programming with the data serving as constraints. Such problems are most easily analyzed when it is possible to segment the solution space into regions that are feasible (satisfying all the known constraints) and infeasible (violating some of the constraints). Then, if the feasible set is convex or at least compact, the solution to the problem will normally lie on the boundary of the feasible set. A nonlinear program may seek the solution by systematically exploring the boundary while satisfying progressively more constraints. Examples of inverse problems in wave propagation (traveltime tomography) and vibration (modal analysis) will be presented to illustrate how the variational structure of these problems may be used to create nonlinear programs using implicit variational constraints.
Scattering and absorption of electromagnetic waves by a Schwarzschild black hole
International Nuclear Information System (INIS)
Fabbri, R.
1975-01-01
The scattering and absorption of electromagnetic waves by a spherically symmetric nonrotating black hole is studied in the Schwarzschild background, by means of the known expansion of the modified Debye potentials in partial waves. The power reflection coefficients and the phase shifts of the partial waves are evaluated at both high and low frequencies. Then the scattering and absorption cross sections of the black hole are determined. It is shown that the black hole is almost unable to absorb electromagnetic waves when the wave length of the radiation is greater than the Schwarzschild radius
Sensor for electromagnetic waves caused by nuclear detonation
International Nuclear Information System (INIS)
Weischedel, R.C.
1980-01-01
An electronic sensor is disclosed, having circuits for identifying electromagnetic radiation signals caused by nuclear detonations. Circuits also are provided for discriminating against false indications due to electromagnetic radiation caused by lightning
Energy Technology Data Exchange (ETDEWEB)
Gulyaev, Yu.V. [Institute of Radioengineering and Electronics of the Russian Academy of Sciences, 125009 Moscow (Russian Federation); Barabanenkov, Yu.N. [Institute of Radioengineering and Electronics of the Russian Academy of Sciences, 125009 Moscow (Russian Federation)]. E-mail: yu.barab@mail.ip.sitek.net; Barabanenkov, M.Yu. [Institute of Microelectronics Technology and High Purity Materials of the Russian Academy of Sciences, 142432 Chernogolovka, Moscow Region (Russian Federation); Nikitov, S.A. [Institute of Radioengineering and Electronics of the Russian Academy of Sciences, 125009 Moscow (Russian Federation)
2005-02-21
We present an optical theorem for evanescent (near field) electromagnetic wave scattering by a dielectric structure. The derivation is based on the formalism of angular spectrum wave amplitudes. The optical theorem shows that an energy flux at scattering is emitted in the direction of incident evanescent wave decay.
On the nature of electromagnetic waves in the vicinity of auroral archs
International Nuclear Information System (INIS)
Volokitin, A.S.; Mordovskaya, V.G.
1988-01-01
Excitation of kinetic Alfven waves by longitudinal current in the vicinity of auroral arcs is considered in the framework of quasilinear theory. It is shown that experimentally observed low-frequency electromagnetic waves with f<2Hz frequency in the vicinity of uniform auroral arcs represent the Alfven waves, excited at altitudes of three Earth radii and above by longitudinal electric current
Damping and scattering of electromagnetic waves by small ferrite spheres suspended in an insulator
Englert, Gerald W.
1992-01-01
The intentional degradation of electromagnetic waves by their penetration into a media comprised of somewhat sparsely distributed energy absorbing ferrite spheres suspended in an electrical insulator is investigated. Results are presented in terms of generalized parameters involving wave length and sphere size, sphere resistivity, permeability, and spacing; their influence on dissipation of wave power by eddy currents, magnetic hysteresis, and scattering is shown.
Localized structures of electromagnetic waves in hot electron-positron plasma
International Nuclear Information System (INIS)
Kartal, S.; Tsintsadze, L.N.; Berezhiani, V.I.
1995-08-01
The dynamics of relatively strong electromagnetic (EM) wave propagation in hot electron-positron plasma is investigated. The possibility of finding localized stationary structures of EM waves is explored. It it shown that under certain conditions the EM wave forms a stable localized soliton-like structures where plasma is completely expelled from the region of EM field location. (author). 9 refs, 2 figs
Directory of Open Access Journals (Sweden)
Song Hee Chae
2017-09-01
Full Text Available We present an electromagnetic linear vibration energy harvester with an array of rectangular permanent magnets as a springless proof mass. Instead of supporting the magnet assembly with spring element, ferrofluid has been used as a lubricating material. When external vibration is applied laterally to the harvester, magnet assembly slides back and forth on the channel with reduced friction and wear due to ferrofluid, which significantly improves the long-term reliability of the device. Electric power is generated across an array of copper windings formed at the bottom of the aluminum housing. A proof-of-concept harvester has been fabricated and tested with a vibration exciter at various input frequencies and accelerations. For the device where 5 μL of ferrofluid was used for lubrication, maximum output power of 493 μW has been generated, which was 4.37% higher than that without ferrofluid. Long-term reliability improvement due to ferrofluid lubrication has also been verified. For the device with ferrofluid, 1.02% decrease of output power has been observed, in contrast to 59.73% decrease of output power without ferrofluid after 93,600 cycles.
Excitation of surface electromagnetic waves in a graphene-based Bragg grating.
Sreekanth, Kandammathe Valiyaveedu; Zeng, Shuwen; Shang, Jingzhi; Yong, Ken-Tye; Yu, Ting
2012-01-01
Here, we report the fabrication of a graphene-based Bragg grating (one-dimensional photonic crystal) and experimentally demonstrate the excitation of surface electromagnetic waves in the periodic structure using prism coupling technique. Surface electromagnetic waves are non-radiative electromagnetic modes that appear on the surface of semi-infinite 1D photonic crystal. In order to fabricate the graphene-based Bragg grating, alternating layers of high (graphene) and low (PMMA) refractive index materials have been used. The reflectivity plot shows a deepest, narrow dip after total internal reflection angle corresponds to the surface electromagnetic mode propagating at the Bragg grating/air boundary. The proposed graphene based Bragg grating can find a variety of potential surface electromagnetic wave applications such as sensors, fluorescence emission enhancement, modulators, etc.
Electromagnetic waves destabilized by runaway electrons in near-critical electric fields
Energy Technology Data Exchange (ETDEWEB)
Komar, A.; Pokol, G. I. [Department of Nuclear Techniques, Budapest University of Technology and Economics, Association EURATOM, H-1111 Budapest (Hungary); Fueloep, T. [Department of Applied Physics, Nuclear Engineering, Chalmers University of Technology and Euratom-VR Association, Goeteborg (Sweden)
2013-01-15
Runaway electron distributions are strongly anisotropic in velocity space. This anisotropy is a source of free energy that may destabilize electromagnetic waves through a resonant interaction between the waves and the energetic electrons. In this work, we investigate the high-frequency electromagnetic waves that are destabilized by runaway electron beams when the electric field is close to the critical field for runaway acceleration. Using a runaway electron distribution appropriate for the near-critical case, we calculate the linear instability growth rate of these waves and conclude that the obliquely propagating whistler waves are most unstable. We show that the frequencies, wave numbers, and propagation angles of the most unstable waves depend strongly on the magnetic field. Taking into account collisional and convective damping of the waves, we determine the number density of runaways that is required to destabilize the waves and show its parametric dependences.
Properties of backward electromagnetic waves and negative reflection in ferrite films
International Nuclear Information System (INIS)
Vashkovsky, Anatolii V; Lock, Edwin H
2006-01-01
For a backward electromagnetic wave (magnetostatic wave) in a ferrite film, reflection from a perfect mirror formed by the straight edge of the film is investigated experimentally and theoretically. It is found that when the incident wave is collinear (the group velocity vector and the wave vector have opposite directions), negative reflection occurs at any angle of incidence, i.e., the incident and reflected beams are on the same side of the normal to the boundary. It is discovered that a noncollinear backward wave is nonreciprocal in the sense that its energy can be localized both near the surface and in the middle of the film. This property, previously observed only for surface magnetostatic waves, provides both the efficiency of generating and receiving the wave and the possibility of observing the reflected beam. A situation is realized where wave reflection results in two reflected beams. The properties of backward electromagnetic waves propagating in ferrite films are briefly analyzed. (methodological notes)
Energy Technology Data Exchange (ETDEWEB)
Brandt, C; Grulke, O; Klinger, T, E-mail: christian.brandt@lpmi.uhp-nancy.f [Max-Planck-Institute for Plasma Physics, EURATOM Association, Wendelsteinstrasse 1, D-17491 Greifswald (Germany)
2010-05-15
Experiments in a cylindrical magnetized plasma on the control of drift waves by means of two different spatiotemporal open-loop control systems-an electrostatic and an electromagnetic exciter-are reported. The drift wave dynamics is controlled by a mode-selective signal created with azimuthal arrangements of eight electrodes and eight saddle coils, respectively. Nonlinear interaction between the control signals and drift waves is observed, leading to synchronization of coherent drift waves and suppression of broadband drift wave turbulence. The cross-phase between density and potential fluctuations reduces from {approx}{pi}/2 in turbulence to {approx}0 in controlled turbulence. Hence, the cross-field transport is reduced to the level of coherent drift waves. For both control systems the coupling to the drift wave can be ascribed to the drive of parallel currents, on the one hand via direct electric contact and, on the other hand, via electromagnetic induction.
Geodetic refraction effects of electromagnetic wave propagation through the atmosphere
1984-01-01
With very few exceptions, geodetic measurements use electro magnetic radiation in order to measure directions, distances, time delays, and Doppler frequency shifts, to name the main ter restrial and space observables. Depending on the wavelength of the radiation and the purpose of the measurements, the follow ing parameters of the electromagnetic wave are measured: ampli tude, phase, angle-of-arrival, polarisation and frequency. Ac curate corrections have to be applied to the measurements in order to take into account the effects of the intervening medium between transmitter and receiver. The known solutions use at mospheric models, special observation programs, remote sensing techniques and instrumental methods. It has been shown that the effects of the earth's atmospheric envelope present a fundamental limitation to the accuracy and precision of geodetic measurements. This applies equally to ter restrial and space applications. Instrumental accuracies are al ready below the atmospherically i...
Scattering of Electromagnetic Waves by Many Nano-Wires
Directory of Open Access Journals (Sweden)
Alexander G. Ramm
2013-07-01
Full Text Available Electromagnetic wave scattering by many parallel to the z−axis, thin, impedance, parallel, infinite cylinders is studied asymptotically as a → 0. Let Dm be the cross-section of the m−th cylinder, a be its radius and xˆm = (xm1, xm2 be its center, 1 ≤ m ≤ M , M = M (a. It is assumed that the points, xˆm, are distributed, so that N (∆ = (1 / 2πa * ∫∆ N (xˆdxˆ[1 + o(1], where N (∆ is the number of points, xˆm, in an arbitrary open subset, ∆, of the plane, xoy. The function, N (xˆ ≥ 0, is a continuous function, which an experimentalist can choose. An equation for the self-consistent (effective field is derived as a → 0. A formula is derived for the refraction coefficient in the medium in which many thin impedance cylinders are distributed. These cylinders may model nano-wires embedded in the medium. One can produce a desired refraction coefficient of the new medium by choosing a suitable boundary impedance of the thin cylinders and their distribution law.
Controlling Energy Radiations of Electromagnetic Waves via Frequency Coding Metamaterials.
Wu, Haotian; Liu, Shuo; Wan, Xiang; Zhang, Lei; Wang, Dan; Li, Lianlin; Cui, Tie Jun
2017-09-01
Metamaterials are artificial structures composed of subwavelength unit cells to control electromagnetic (EM) waves. The spatial coding representation of metamaterial has the ability to describe the material in a digital way. The spatial coding metamaterials are typically constructed by unit cells that have similar shapes with fixed functionality. Here, the concept of frequency coding metamaterial is proposed, which achieves different controls of EM energy radiations with a fixed spatial coding pattern when the frequency changes. In this case, not only different phase responses of the unit cells are considered, but also different phase sensitivities are also required. Due to different frequency sensitivities of unit cells, two units with the same phase response at the initial frequency may have different phase responses at higher frequency. To describe the frequency coding property of unit cell, digitalized frequency sensitivity is proposed, in which the units are encoded with digits "0" and "1" to represent the low and high phase sensitivities, respectively. By this merit, two degrees of freedom, spatial coding and frequency coding, are obtained to control the EM energy radiations by a new class of frequency-spatial coding metamaterials. The above concepts and physical phenomena are confirmed by numerical simulations and experiments.
Impact of Mobile Phone Electromagnetic Waves on Brainwaves
Directory of Open Access Journals (Sweden)
Fu-Chien Kao
2015-07-01
Full Text Available In the era of wireless communication, cellular phone becomes an indispensable accessory to most people. People use cellular phone to interact with others, perform commercial and financial transactions, or conducting recreational activities, etc. The advance in wireless technology and escalate of broadband networks not only flourish communications industry and application service providers but also encourage people perform prolonged wireless network activities under the risk of over exposing themselves in long term high frequency electromagnetic waves. For example, some people conduct excessive phone-trading activities, as it is necessary to the job, and some people exercise the non-stop e-learning or recreation activities on mobile devices with long hours. However, would prolonged exposure to high frequency EMW environment bring adverse effects on human health? This research from the perspective of cognitive neuroscience investigates the effect of EMW from cellular phone to the energy distribution of human brainwave characteristic band by examine brainwave changes of test subjects when exposing to high frequency EMW environment. Experiment uses left ear and right ear to answer the phone separately. The calling session is divided into three stages: the instant of call connection, during the call, and after the call. On each ear, the brainwave signal of each calling stage is extracted and analyzed. The experiment shows at the instant of call connection stage, resulting maximum EMW strength, having extreme effect on the energy distribution of the human brainwave characteristic band, and causing severe changes on the energy of human brainwave.
Dispersion of linearly polarized electromagnetic wave in magnetized quantum plasma
International Nuclear Information System (INIS)
Singh, Abhisek Kumar; Kumar, Punit
2015-01-01
The generation of harmonic radiation is significant in terms of laser-plasma interaction and has brought interesting notice due to the diversity of its applications. The odd harmonics of laser frequency are generated in the majority of laser interactions with homogenous plasma. It has been remarked that second harmonic generation takes place in the presence of density gradient which gives rise to perturbation in the electron density at the laser frequency. The density perturbation coupled with the quiver motion of the electrons produces a source current at the second harmonic frequency. Second harmonic generation has also been related with filamentation. In the present paper, a study of second harmonic generation by propagation of a linearly polarized electromagnetic wave through homogeneous high density quantum plasma in the presence of transverse magnetic field. The nonlinear current density and dispersion relations for the fundamental and second harmonic frequencies have been obtained using the recently developed quantum hydrodynamic (QHD) model. The effect of quantum Bohm potential, Fermi pressure and the electron spin have been taken into account. The second harmonic is found to be less dispersed than the first. (author)
Radiation of planar electromagnetic waves by a line source in anisotropic metamaterials
International Nuclear Information System (INIS)
Cheng Qiang; Jiang Weixiang; Cui Tiejun
2010-01-01
We show experimentally that a line source in an anisotropic metamaterial directly radiates planar electromagnetic waves instead of cylindrical waves, when one component of the permeability tensor approaches zero. The impedance of this material can be perfectly matched to that of free space, which can significantly reduce the reflections between the source and the superstrate, as in traditional highly directive antennas based on zero index metamaterials. Such a unique property determines the two-way propagation of electromagnetic waves excited by a line source, instead of all-way propagation. From this feature, a highly directive emission of electromagnetic waves is achieved using the anisotropic metamaterial with arbitrary shape. We have designed and fabricated the anisotropic metamaterial in the microwave region, and observed the generation of plane waves and their highly directive emission. The proposed plane-wave emission is independent of the shape variance of the anisotropic metamaterial, which can be utilized in the design of conformal antennas.
Effect of a gravitational wave on electromagnetic radiation confined in a cavity
International Nuclear Information System (INIS)
Tourrenc, P.
1978-01-01
Gravitational radiation is considered within the first-order approximation. A pattern of an electromagnetic cavity is studied: Gravitational waves give rise to a deformation of the planes limiting the cavity. This deformation alters the electromagnetic radiation. Several cases are studied and orders of magnitude are put forward. (author)
Grobbe, N.
2016-01-01
In this thesis, I study coupled poroelastic waves and electromagnetic fields in layered media. The focus is two-fold:
1. Increase the theoretical and physical understanding of the seismo-electromagnetic phenomenon by analytically-based numerical modeling.
2. Investigate the potential of
Solution of the Bethe-Salpeter equation in the field of a plane electromagnetic wave
International Nuclear Information System (INIS)
Starostin, V.S.
1988-01-01
A solution is obtained of the Bethe--Salpeter equation for positronium in the field of linearly and circularly polarized plane electromagnetic waves at frequencies much higher than atomic. It is not assumed that the field is weak
Simulation study of localization of electromagnetic waves in two-dimensional random dipolar systems
International Nuclear Information System (INIS)
Wang, Ken Kang-Hsin; Ye Zhen
2003-01-01
We study the propagation and scattering of electromagnetic waves by random arrays of dipolar cylinders in a uniform medium. A set of self-consistent equations, incorporating all orders of multiple scattering of the electromagnetic waves, is derived from first principles and then solved numerically for electromagnetic fields. For certain ranges of frequencies, spatially localized electromagnetic waves appear in such a simple but realistic disordered system. Dependence of localization on the frequency, radiation damping, and filling factor is shown. The spatial behavior of the total, coherent, and diffusive waves is explored in detail, and found to comply with a physical intuitive picture. A phase diagram characterizing localization is presented, in agreement with previous investigations on other systems
Bai, Zhengyang; Xu, Datang; Huang, Guoxiang
2017-01-23
We propose a scheme to realize the storage and retrieval of high-dimensional electromagnetic waves with orbital angular momentum (OAM) via plasmon-induced transparency (PIT) in a metamaterial, which consists of an array of meta-atoms constructed by a metallic structure loaded with two varactors. We show that due to PIT effect the system allows the existence of shape-preserving dark-mode plasmonic polaritons, which are mixture of electromagnetic-wave modes and dark oscillatory modes of the meta-atoms and may carry various OAMs. We demonstrate that the slowdown, storage and retrieval of multi-mode electromagnetic waves with OAMs can be achieved through the active manipulation of a control field. Our work raises the possibility for realizing PIT-based spatial multi-mode memory of electromagnetic waves and is promising for practical application of information processing with large capacity by using room-temperature metamaterials.
Simulation study of localization of electromagnetic waves in two-dimensional random dipolar systems.
Wang, Ken Kang-Hsin; Ye, Zhen
2003-12-01
We study the propagation and scattering of electromagnetic waves by random arrays of dipolar cylinders in a uniform medium. A set of self-consistent equations, incorporating all orders of multiple scattering of the electromagnetic waves, is derived from first principles and then solved numerically for electromagnetic fields. For certain ranges of frequencies, spatially localized electromagnetic waves appear in such a simple but realistic disordered system. Dependence of localization on the frequency, radiation damping, and filling factor is shown. The spatial behavior of the total, coherent, and diffusive waves is explored in detail, and found to comply with a physical intuitive picture. A phase diagram characterizing localization is presented, in agreement with previous investigations on other systems.
Electromagnetic surface waves at the interface of a relativistic electron beam with vacuum
International Nuclear Information System (INIS)
Shoucri, M.M.; Gagne, R.R.J.
1977-01-01
The dispersion relation for electromagnetic surface waves propagating at the interface between a relativistic electron beam and vacuum is derived. The excitation of surface modes in a plasma at rest by a relativistic electron beam is discussed
International Nuclear Information System (INIS)
Yuksek, N. S.; Almasri, M.; Feng, Z. C.
2014-01-01
In this paper, we propose an electromagnetic power harvester that uses a transformative multi-impact approach to achieve a wide bandwidth response from low frequency vibration sources through frequency-up conversion. The device consists of a pick-up coil, fixed at the free edge of a cantilever beam with high resonant frequency, and two cantilever beams with low excitation frequencies, each with an impact mass attached at its free edge. One of the two cantilevers is designed to resonate at 25 Hz, while the other resonates at 50 Hz within the range of ambient vibration frequency. When the device is subjected to a low frequency vibration, the two low-frequency cantilevers responded by vibrating at low frequencies, and thus their thick metallic masses made impacts with the high resonance frequency cantilever repeatedly at two locations. This has caused it along with the pick-up coil to oscillate, relative to the permanent magnet, with decaying amplitude at its resonance frequency, and results in a wide bandwidth response from 10 to 63 Hz at 2 g. A wide bandwidth response between 10–51 Hz and 10–58 Hz at acceleration values of 0.5 g and 2 g, respectively, were achieved by adjusting the impact cantilever frequencies closer to each other (25 Hz and 45 Hz). A maximum output power of 85 μW was achieved at 5 g at 30 Hz across a load resistor, 2.68 Ω.
Influence of Sea Surface Roughness on the Electromagnetic Wave Propagation in the Duct Environment
Zhao, X.; Huang, S.
2010-01-01
This paper deals with a study of the influence of sea surface roughness on the electromagnetic wave propagation in the duct environment. The problem of electromagnetic wave propagation is modeled by using the parabolic equation method. The roughness of the sea surface is computed by modifying the smooth surface Fresnel reflection coefficient to account for the reduction in the specular reflection due to the roughness resulting from sea wind speed. The propagation model is solved by the mixed ...
Wake-Field Wave Resonant Excitation in Magnetized Plasmas by Electromagnetic Pulse
International Nuclear Information System (INIS)
Milant'ev, V.P.; Turikov, V.A.
2006-01-01
In this paper the space charge wave excitation process at electromagnetic pulse propagation along external magnetic field in vicinity of electron cyclotron resonance. In hydrodynamic approach it is obtained an equation for plasma density under ponderomotive force action. With help of this equation we investigated a wake-field wave amplitude dependence from resonance detuning. The numerical simulation using a PIC method electromagnetic pulse propagation process in the resonant conditions was done
International Nuclear Information System (INIS)
Sagdeev, R.Z.; Shapiro, V.D.; Shevchenko, V.I.
1980-01-01
An attempt is made to analyze two assumptions of the present theory of plasma turbulence, initiated by an electromagnetic wave, as applied to the problem of heating the plasma target. It has been assumed that in the long-scale region (the region of an electromagnetic wave source) and in the inertia range, separating the source region and the short-wave absorption region, there is a permanent pumping. The first assumption consists in simulating a situation in a plasma target when the Langmuir turbulence arises due to an electromagnetic wave incident on the target. The second assumption is valid only at a very high intensity of plasma waves when their energy is significantly less than the thermal energy of plasma W/nsub(c)T 0 is the frequency of an incident electromagnetic wave). At W approximately equal to nsub(c)T the plasma oscillations, arising due to modulation instability from the electromagnetic pumping wave, fall immediately into the absorption region. A phenomenological theory of such a turbulence, called ''superstrong'', is formulated on the assumption that there is a mechanism of ''mixing up'' plasmon phases as a result of their populating the long-wave density fluctuations
Electromagnetic wave propagation in a medium with a progressive sinusoidal fluctuation
International Nuclear Information System (INIS)
Ito, Hiroshi; Ito, Akinari
1984-01-01
Study was made on the rigorous solutions for electromagnetic waves transmitted and reflected by a medium of finite length with time-space periodic fluctuation, loaded in a rectangular waveguide. When an electromagnetic wave is incident upon the medium modulated in a travelling wave fashion by a pump wave, the reflected and transmitted waves are shifted in frequency by +nω 1 (where n is an integer, ω 1 is the angular frequency of fluctuation). The harmonic level of the reflected waves is much increased as the frequency of the incident wave approaches the cutoff-frequency of TE 10 mode of the rectangular waveguide. Measurement of the spectrum of the reflected waves can be utilized as a diagnosis of even a very slightly fluctuating medium. The theoretical results have been verified on examining experimentally the harmonic level of the microwave reflected by a plasma, weakly modulated (about 10 -4 ) by RF signal and loaded in the WRJ-10 waveguide. (author)
A Study of Active Rotor-Blade Vibration Control using Electro-Magnetic Actuation - Part I: Theory
DEFF Research Database (Denmark)
Christensen, Rene Hardam; Santos, Ilmar
2004-01-01
actuators fixed directly in the blades. However, due to the impracticability and problems by fixing actuators in the rotating blades, it is for practical application of great interest to study whether the vibrations can be controlled using shaft-based actuators, i.e. electro-magnetic bearings...
Conversion of electromagnetic waves at the ionisation front
International Nuclear Information System (INIS)
Chegotov, M V
2001-01-01
It is shown that a weak electromagnetic pulse interacting with a copropagating ionisation front is converted in the general case into three electromagnetic pulses with higher and lower frequencies, which propagate in different directions. The coefficients of conversion to these pulses (for intensities) were found as functions of the frequency. The electromagnetic energy is shown to decrease during this conversion because of the losses for the residual electron energy. (interaction of laser radiation with matter. laser plasma)
Sound excitation at reflection of two electromagnetic waves from dence semibounded plasma
International Nuclear Information System (INIS)
Livdan, D.O.; Muratov, V.I.; Shuklin, A.P.
1988-01-01
The problem of two electromagnetic waves reflection by semibounded plasma which is nontransparent for each of these waves is solved. The reflection coefficients are obtained for normally incident waves. It is shown that the moduli of the reflection coefficients differ from the unit and this is due to the interaction of the external raiation with the acoustic wave excited in plasma. The energy flux in plasma is calculated
Analysis of multidimensional measurements of electromagnetic waves in the Earth's magnetosphere
Pechal, Radim
2011-01-01
Title: Analysis of multidimensional measurements of electromagnetic waves in the Earth's magnetosphere Author: Radim Pechal Department: Department of Surface and Plasma Science Supervisor: doc. RNDr. Lubomír Přech, Dr. Supervisor's e-mail address: Abstract: The thesis introduces into basic knowledge of waves in plasma, especially waves in the Earth's magnetosphere. There are mentioned some space projects focused on chorus waves. The second part of this thesis is a la...
DEFF Research Database (Denmark)
Stein, George Juraj; Darula, Radoslav; Sorokin, Sergey
2012-01-01
A theoretical analysis of an electromagnetic vibration controller is presented. The analyzed device consists of a pot-type iron core with a coil and a permanent magnet as a source of constant magnetic flux. The magnetic circuit is closed by a yoke, excited by an external harmonic mechanical force....... The so generated magnetic flux variation induces alternating voltage in the electric circuit, which is dissipated in a shunt resistor. The induced current driven through the coil generates magnetic force, which damps the excitation force and changes the damped natural frequency of the oscillatory system....... Due to the hysteretic effects in the magnetic material the internal losses influence the overall system’s performance. A mathematical model of the force balance in the oscillatory system is derived in a simplified, linearised form. The electric as well as mechanical system is modelled using lumped...
Directory of Open Access Journals (Sweden)
Yao-Yun Feng
2017-03-01
Full Text Available A conductive direct-write process of multilayered coils for micro electromagnetic generators is proposed. This novel approach of using silver ink to form the conductive structures largely reduces the fabrication complexity, and it provides a faster alternative to the conventional semiconductor methods. Multi-layered coils with insulation were accurately layered on a micromachined cantilevered diaphragm by a dispenser. Coils several layers thick could be used to increase the power output and double coils were separated by a layer of insulation. Six prototypes, all capable of efficient conversion of vibrational energy into electrical energy, were fabricated. The experimental results, which include measurements of the electromotive force and power output, are presented. Prototypes with two coils and thicker conducting layers had less resistance and the power output was much more than that of a single-coil unit. This generator can produce 82 nW of power at a resonance frequency of 275 Hz under 5 g excitation.
Vibration Energy Harvesting on Vehicle Suspension Using Rotary and Linear Electromagnetic Generator
Directory of Open Access Journals (Sweden)
Arif Indro Sultoni
2013-04-01
Full Text Available In this paper, we discuss comparation of vehicle vibration energy harvesting between rotary and linear electromagnetic generator. We construct the two model of energy harvester mechanism and then analyze both of energy absorbtion and vehicle comfortability. Furthermore, we analyze both of energy absorbtion and vehicle comfortability. Vehicle is modeled as quarter car. Rotarty generator harvests 2.5 x 10-4 Watt. The other hand, linear generator has viscous characteristic and capable to generates 90 Watts with 12 Volt power supply for 0.03 m amplitude of bumpy road input. Linear generator reduces oscillation with 1.2 sec settling time. It is more comfort than the angular which has 3 sec in settling time. With unnevenees road input, mean power of this generator is 64 Watt.
Pancharoen, K.; Zhu, D.; Beeby, S. P.
2016-11-01
This paper presents a magnetically levitated electromagnetic vibration energy harvester based on magnet arrays. It has a nonlinear response that extends the operating bandwidth and enhances the power output of the harvesting device. The harvester is designed to be embedded in a hip prosthesis and harvest energy from low frequency movements (< 5 Hz) associated with human motion. The design optimization is performed using Comsol simulation considering the constraints on size of the harvester and low operating frequency. The output voltage across the optimal load 3.5kΩ generated from hip movement is 0.137 Volts during walking and 0.38 Volts during running. The power output harvested from hip movement during walking and running is 5.35 μW and 41.36 μW respectively..
International Nuclear Information System (INIS)
Hashimoto, K.; Yamaashi, K.; Kimura, I.; Kyoto Univ., Japan)
1987-01-01
Three-dimensional ray tracing is performed for electrostatic electron cyclotron harmonic waves and Z mode electromagnetic waves in the earth's magnetosphere using the hot dispersion relation. Propagation characteristics of cyclotron harmonic waves under the electrostatic approximation are considered, and it is noted that waves starting near the equator can propagate over a long distance without damping. Ray tracing without the electrostatic approximation confirms mode conversion from cyclotron harmonic waves to Z mode electromagnetic waves, and the conditions for the conversion are clarified. It is suggested that further conversion to the L-O mode continuum radiation is possible under strict constraints. The present results are not inconsistent with the conversion mechanism for the generation of escaping continuum radiation in the magnetosphere. 20 references
Interaction of electromagnetic waves with plasma in the radiation-dominated regime
International Nuclear Information System (INIS)
Bulanov, S.V.; Esirkepov, T.Zh.; Koga, J.; Tajima, T.
2004-01-01
A study is made of the main regimes of interaction of relativistically strong electromagnetic waves with plasma under conditions in which the radiation from particles plays a dominant role. The discussion is focused on such issues as the generation of short electromagnetic pulses in the interaction of laser light with clusters and highly efficient ion acceleration in a thin plasma slab under the action of the ponderomotive pressure of the wave. An approach is developed for generating superintense electromagnetic pulses by means of up-to-date laser devices
Seomun, GyeongAe; Kim, YoungHwan; Lee, Jung-Ah; Jeong, KwangHoon; Park, Seon-A; Kim, Miran; Noh, Wonjung
2014-04-01
To better understand environmental electromagnetic wave exposure during the use of digital textbooks by elementary school students, we measured numeric values of the electromagnetic fields produced by tablet personal computers (TPCs). Specifically, we examined the distribution of the electromagnetic waves for various students' seating positions in an elementary school that uses digital textbooks. Electric and magnetic fields from TPCs were measured using the HI-3603 Visual Display Terminal/ Very Low Frequency (VDT/VLF) radiation measurement system. Electromagnetic field values from TPCs measured at a student's seat and at a teacher's computer were deemed not harmful to health. However, electromagnetic field values varied based on the distance between students, other electronic devices such as a desktop computers, and student posture while using a TPC. Based on these results, it is necessary to guide students to observe proper posture and to arrange seats at an appropriate distance in the classroom.
Effects of chronic exposure to electromagnetic waves on the auditory system.
Özgür, Abdulkadir; Tümkaya, Levent; Terzi, Suat; Kalkan, Yıldıray; Erdivanlı, Özlem Çelebi; Dursun, Engin
2015-08-01
The results support that chronic electromagnetic field exposure may cause damage by leading to neuronal degeneration of the auditory system. Numerous researches have been done about the risks of exposure to the electromagnetic fields that occur during the use of these devices, especially the effects on hearing. The aim of this study is to evaluate the effects of the electromagnetic waves emitted by the mobile phones through the electrophysiological and histological methods. Twelve adult Wistar albino rats were included in the study. The rats were divided into two groups of six rats. The study group was exposed to the electromagnetic waves over a period of 30 days. The control group was not given any exposure to the electromagnetic fields. After the completion of the electromagnetic wave application, the auditory brainstem responses of both groups were recorded under anesthesia. The degeneration of cochlear nuclei was graded by two different histologists, both of whom were blinded to group information. The histopathologic and immunohistochemical analysis showed neuronal degeneration signs, such as increased vacuolization in the cochlear nucleus, pyknotic cell appearance, and edema in the group exposed to the electromagnetic fields compared to the control group. The average latency of wave in the ABR was similar in both groups (p > 0.05).
International Nuclear Information System (INIS)
Cho, Sang Won; Koo, Jeong Hoi; Jo, Ji Seong
2007-01-01
This paper presents a novel electromagnetic induction (EMI) system integrated in magneto rheological (MR) dampers: The added EMI system converts reciprocal motions of MR damper into electiral energy (electromotive force or emf) according to the Faraday's law of electromagnetic induction. Maximum energy dissipation algorithm (MEDA) is employed to regulate the MR dampers because it strives to simplify a complex design process by employing the Lyapunov's direct approach. The emf signal, produced from the EMI, provides the necessary measurement information (i.e., realtive velocity across the damper) for the MEDA controller. Thus, the EMI acts as a sensor in the proposed MR-EMI system. In order to evaluate the performance and robustness of the MR-EMI sensor system with the MEDA control, this study performed an extensive simulation study using the first generation benchmark cable-stayed bridge. Moreover, it compared the performance and the robustness of proposed system with those of Clipped-Optimal Control (COC) and Sliding Mode Control (SMC), which were previously studied for the benchmark cable-stayed bridge. The results show that the MR-EMI system reduced the vibrations of the bridge structure more than those of COC and SMC and show more robust performance than that of SMC. These results suggest that EMIs can be used cost-effective sensing devices for MR damper control systems without compromising the performance of them
Elastic metamaterials for tuning circular polarization of electromagnetic waves.
Zárate, Yair; Babaee, Sahab; Kang, Sung H; Neshev, Dragomir N; Shadrivov, Ilya V; Bertoldi, Katia; Powell, David A
2016-06-20
Electromagnetic resonators are integrated with advanced elastic material to develop a new type of tunable metamaterial. An electromagnetic-elastic metamaterial able to switch on and off its electromagnetic chiral response is experimentally demonstrated. Such tunability is attained by harnessing the unique buckling properties of auxetic elastic materials (buckliballs) with embedded electromagnetic resonators. In these structures, simple uniaxial compression results in a complex but controlled pattern of deformation, resulting in a shift of its electromagnetic resonance, and in the structure transforming to a chiral state. The concept can be extended to the tuning of three-dimensional materials constructed from the meta-molecules, since all the components twist and deform into the same chiral configuration when compressed.
Directory of Open Access Journals (Sweden)
Salar Chamanian
2014-10-01
Full Text Available This paper presents a wireless sensor node (WSN system where an electromagnetic (EM energy harvester is utilized for charging its rechargeable batteries while the system is operational. The capability and the performance of an in-house low-frequency EM energy harvester for charging rechargeable NiMH batteries were experimentally verified in comparison to a regular battery charger. Furthermore, the power consumption of MicaZ motes, used as the WSN, was evaluated in detail for different operation conditions. The battery voltage and current were experimentally monitored during the operation of the MicaZ sensor node equipped with the EM vibration energy harvester. A compact (24.5 cm3 in-house EM energy harvester provides approximately 65 µA charging current to the batteries when excited by 0.4 g acceleration at 7.4 Hz. It has been shown that the current demand of the MicaZ mote can be compensated for by the energy harvester for a specific low-power operation scenario, with more than a 10-fold increase in the battery lifetime. The presented results demonstrate the autonomous operation of the WSN, with the utilization of a vibration-based energy harvester.
International Nuclear Information System (INIS)
Hong, Liu; He, X.T.; Chen, S.G.; Zhang, W.Y.; He, X.T.; Hong, Liu
2004-01-01
We propose a new particle acceleration mechanism. Electrons can be accelerated to relativistic energy within a few electromagnetic wave cycles through the mechanism which is named electromagnetic and magnetic field resonance acceleration (EMRA). We find that the electron acceleration depends not only on the electromagnetic wave intensity, but also on the ratio between electron Larmor frequency and electromagnetic wave frequency. As the ratio approaches to unity, a clear resonance peak is observed, corresponding to the EMRA. Near the resonance regime, the strong magnetic fields still affect the electron acceleration dramatically. We derive an approximate analytical solution of the relativistic electron energy in adiabatic limit, which provides a full understanding of this phenomenon. In typical parameters of pulsar magnetospheres, the mechanism allows particles to increase their energies through the resonance of high magnetic field and high frequency electromagnetic wave in each electromagnetic wave period. The energy spectra of the accelerated particles exhibit the synchrotron radiation behavior. These can help to understand the remaining emission of high energy electron from radio pulsar within supernova remnant. The other potential application of our theory in fast ignition scheme of inertial confinement fusion is also discussed. (authors)
Conditions for sustaining low-pressure plasma columns by travelling electromagnetic UHF waves
International Nuclear Information System (INIS)
Benova, E.; Zhelyazkov, I.
1997-01-01
The paper considers the conditions for sustaining low-pressure plasma columns by travelling electromagnetic waves in symmetric and dipolar modes, respectively. The treatment is fully electrodynamic. It is shown that the wave energy flux along the plasma column determines the conditions for sustaining the discharge. In particular as the plasma is sustained by a symmetric wave whose flux depends mainly on the radial distribution of the wave electric field whilst for a dipolar wave sustained plasma the flux is specified by the magnitude of the axial wave field component at the plasma-dielectric interface. (orig.)
Population of vibrational levels of carbon dioxide by cylindrical fast ionization wave
Levko, Dmitry; Pachuilo, Michael; Raja, Laxminarayan L.
2017-01-01
The population of vibrational levels of carbon dioxide (CO2) by a cylindrical fast ionization wave is analyzed using a one-dimensional Particle-in-Cell Monte Carlo collisions model. The model takes into account the inelastic electron
Rojas, R.; Robles, P.
2011-01-01
We discuss common features in mechanical, electromagnetic and quantum systems, supporting identical results for the transmission and reflection coefficients of waves arriving perpendicularly at a plane interface. Also, we briefly discuss the origin of special notions such as refractive index in quantum mechanics, massive photons in wave guides and…
Electromagnetic waves in a layer of hot plasma with negligible collisions
International Nuclear Information System (INIS)
Vacca, J.
1975-01-01
The propagation of electromagnetic waves in a plane plasma layer in a uniform magnetic field has been studied, following the hypothesis of immoble ions and negligible ion-electron interactions. Waves dependent on one spatial coordinate are considered and all the parameters of the problems are considered. The cases of perpendicular and parallel magnetic field are treated
The Relativistic Transformation for an Electromagnetic Plane Wave with General Time Dependence
Smith, Glenn S.
2012-01-01
In special relativity, the transformation between inertial frames for an electromagnetic plane wave is usually derived for the time-harmonic case (the field is a sinusoid of infinite duration), even though all practical waves are of finite duration and may not even contain a dominant sinusoid. This paper presents an alternative derivation in which…
Berberyan, A. Kh; Garakov, V. G.
2018-04-01
A large number of works have been devoted to investigation of the influence of the piezoelectric properties of a material on the propagation of elastic waves [1–3]. Herewith, the quasi-static piezoelasticity model was mainly used. In the problem of an electromagnetic wave reflection from an elastic medium with piezoelectric properties, it is necessary to consider hyperbolic equations [4].
Tokman, M. D.; Westerhof, E.; Gavrilova, M. A.
2000-01-01
The special features of the propagation of electromagnetic waves in gyrotropic medium with dispersion and resonant dissipation (specifically, in a magnetoactive plasma) are studied. Even though the anti-Hermitian components of the permittivity tensor are substantial in magnitude, weakly damped waves
Electromagnetic Waves with Frequencies Near the Local Proton Gryofrequency: ISEF-3 1 AU Observations
Tsurutani, B.
1993-01-01
Low Frequency electromagnetic waves with periods near the local proton gyrofrequency have been detected near 1 AU by the magnetometer onboard ISEE-3. For these 1 AU waves two physical processes are possible: solar wind pickup of nuetral (interstellar?) particles and generation by relativistic electron beams propagating from the Sun.
Energy Technology Data Exchange (ETDEWEB)
Light, Max Eugene [Los Alamos National Laboratory
2017-04-13
This report outlines the theory underlying electromagnetic (EM) wave propagation in an unmagnetized, inhomogeneous plasma. The inhomogeneity is given by a spatially nonuniform plasma electron density n_{e}(r), which will modify the wave propagation in the direction of the gradient rn_{e}(r).
International Nuclear Information System (INIS)
Alinejad, H.; Robinson, P. A.; Cairns, I. H.; Skjaeraasen, O.; Sobhanian, S.
2007-01-01
Nucleating and collapsing wave packets relevant to electromagnetic strong plasma turbulence are studied theoretically in two dimensions. Model collapsing Langmuir and transverse potentials are constructed as superpositions of approximate eigenstates of a spherically symmetric density well. Electrostatic and electromagnetic potentials containing only components with azimuthal quantum numbers m=0, 1, 2 are found to give a good representation of the electric fields of nucleating collapsing wave packets in turbulence simulations. The length scales of these trapped states are related to the electron thermal speed v e and the length scale of the density well. It is shown analytically that the electromagnetic trapped states change with v e and that for v e e > or approx. 0.17c, the Langmuir and transverse modes remain coupled during collapse, with autocorrelation lengths in a constant ratio. An investigation of energy transfer to packets localized in density wells shows that the strongest power transfer to the nucleating state occurs for Langmuir waves. Energy transitions between different trapped and free states for collapsing wave packets are studied, and the transition rate from trapped Langmuir to free plane electromagnetic waves is calculated and related to the emission of electromagnetic waves at the plasma frequency
International Nuclear Information System (INIS)
Graham, D. B.; Robinson, P. A.; Cairns, Iver H.; Skjaeraasen, O.
2011-01-01
Large-scale simulations of wave packet collapse are performed by numerically solving the three-dimensional (3D) electromagnetic Zakharov equations, focusing on individual wave packet collapses and on wave packets that form in continuously driven strong turbulence. The collapse threshold is shown to decrease as the electron thermal speed ν e /c increases and as the temperature ratio T i /T e of ions to electrons decreases. Energy lost during wave packet collapse and dissipation is shown to depend on ν e /c. The dynamics of density perturbations after collapse are studied in 3D electromagnetic strong turbulence for a range of T i /T e . The structures of the Langmuir, transverse, and total electric field components of wave packets during strong turbulence are investigated over a range of ν e /c. For ν e /c e /c > or approx. 0.17, transverse modes become trapped in density wells and contribute significantly to the structure of the total electric field. At all ν e /c, the Langmuir energy density contours of wave packets are predominantly oblate (pancake shaped). The transverse energy density contours of wave packets are predominantly prolate (sausage shaped), with the major axis being perpendicular to the major axes of the Langmuir component. This results in the wave packet becoming more nearly spherical as ν e /c increases, and in turn generates more spherical density wells during collapse. The results obtained are compared with previous 3D electrostatic results and 2D electromagnetic results.
Self-generation and management of spin-electromagnetic wave solitons and chaos
International Nuclear Information System (INIS)
Ustinov, Alexey B.; Kondrashov, Alexandr V.; Nikitin, Andrey A.; Kalinikos, Boris A.
2014-01-01
Self-generation of microwave spin-electromagnetic wave envelope solitons and chaos has been observed and studied. For the investigation, we used a feedback active ring oscillator based on artificial multiferroic, which served as a nonlinear waveguide. We show that by increasing the wave amplification in the feedback ring circuit, a transition from monochromatic auto-generation to soliton train waveform and then to dynamical chaos occurs in accordance with the Ruelle-Takens scenario. Management of spin-electromagnetic-wave solitons and chaos parameters by both dielectric permittivity and magnetic permeability of the multiferroic waveguiding structure is demonstrated.
Spectrum of harmonic emission by inhomogeneous plasma in intense electromagnetic wave
International Nuclear Information System (INIS)
Kovalev, V.F.; Pustovalov, V.V.
1989-01-01
The spectrum and angular distribution of the harmonics of arbitrary index emitted by a cold, inhomogeneous electron plasma subjected to a p-polarized electromagnetic wave have been studied analytically. The results are shown in graphical form. The intensity of the wave was varied over a wide range. At energy flux densities of the electromagnetic wave at which the inverse effect of the higher harmonics on the lower harmonics becomes appreciable, it becomes possible to observe a decay of the absolute value of the complex amplitude of a harmonic with increasing harmonic index in vacuum which is substantially slower than that predicted by the theory for a weak nonlinearity
Wireless system controlling of electromagnetic wave distribution in nuclear power plant use
International Nuclear Information System (INIS)
Kuroda, Hidehiko; Kume, Naoto; Oshima, Tomomi; Takakura, Kei; Oda, Naotaka; Hasegawa, Takeshi; Odanaka, Shigeru
2017-01-01
Recently, wireless technologies have rapidly spread by cellular phones, smartphones and tablet devices. Wireless systems in the nuclear power plant are expected to bring various advantages such as shortening of the inspection time, online monitoring, remote control and cable reduction, etc. However, wireless systems have hardly applied to the nuclear power plant, from the point of security and electromagnetic interference (EMI). We propose a new wireless system controlling automatically electromagnetic wave distribution. In our wireless system, the transmitter / receiver modules automatically measure the wave strength and adjust the power and directivity of the wave, resulting in wireless communication only in target zones, i.e. non-influence to safety-related instruments and non-leakage of information. We will present the algorithm of the electromagnetic wave controlling and experimental results about the proposed system. (author)
On electromagnetic wave propagation through a plasma sheath produced by a moving ionization source
International Nuclear Information System (INIS)
Semenova, V.I.
1977-01-01
Features of the interaction of electromagnetic waves are considered with a nonstationary plasma layer of a finite thickness, produced in an immovable gas by a movable ionization source. It is shown that a static magnetic field excited on the ionization front in build-up of electrons produced in the incident wave field reemits the energy to the electromagnetic wave during the plasma relaxation caused by recombination processes. As a result the electromagnetic wave of a finite amplitude may propagate behind the nonstationary layer of an ''opaque'' (ωsub(p)sup(2)>>ωsub(urc)sup((0))sup(2)) plasma as distinct from the layer of a movable stationary plasma with the same parameters
Controlling of the electromagnetic solitary waves generation in the wake of a two-color laser
Pan, K. Q.; Li, S. W.; Guo, L.; Yang, D.; Li, Z. C.; Zheng, C. Y.; Jiang, S. E.; Zhang, B. H.; He, X. T.
2018-05-01
Electromagnetic solitary waves generated by a two-color laser interaction with an underdense plasma are investigated. It is shown that, when the former wave packet of the two-color laser is intense enough, it will excite nonlinear wakefields and generate electron density cavities. The latter wave packets will beat with the nonlinear wakefield and generate both high-frequency and low-frequency components. When the peak density of the cavities exceeds the critical density of the low-frequency component, this part of the electromagnetic field will be trapped to generate electromagnetic solitary waves. By changing the laser and plasma parameters, we can control the wakefield generation, which will also control the generation of the solitary waves. One-dimensional particle-in-cell simulations are performed to prove the controlling of the solitary waves. The simulation results also show that solitary waves generated by higher laser intensities will become moving solitary waves. The two-dimensional particle-in-cell also shows the generation of the solitary waves. In the two-dimensional case, solitary waves are distributed in the transverse directions because of the filamentation instability.
Excitation of Surface Electromagnetic Waves on Railroad Rail
1978-03-31
UMTA's Office of Rail Technology research programs aim to improve urban rail transportation systems safety. This rail-transit research study attempts to develop an onboard, separate and independent obstacle-detection system--Surface Electromagnetic W...
Shoji, Masafumi; Miyoshi, Yoshizumi; Katoh, Yuto; Keika, Kunihiro; Angelopoulos, Vassilis; Kasahara, Satoshi; Asamura, Kazushi; Nakamura, Satoko; Omura, Yoshiharu
2017-09-01
Electromagnetic plasma waves are thought to be responsible for energy exchange between charged particles in space plasmas. Such an energy exchange process is evidenced by phase space holes identified in the ion distribution function and measurements of the dot product of the plasma wave electric field and the ion velocity. We develop a method to identify ion hole formation, taking into consideration the phase differences between the gyromotion of ions and the electromagnetic ion cyclotron (EMIC) waves. Using this method, we identify ion holes in the distribution function and the resulting nonlinear EMIC wave evolution from Time History of Events and Macroscale Interactions during Substorms (THEMIS) observations. These ion holes are key to wave growth and frequency drift by the ion currents through nonlinear wave-particle interactions, which are identified by a computer simulation in this study.
Traveling waves in a free-electron laser with an electromagnetic wiggler
International Nuclear Information System (INIS)
Olumi, Mohsen; Maraghechi, B; Rouhani, M H
2011-01-01
The propagation of electromagnetic traveling wave in a free-electron laser (FEL) with an electromagnetic wiggler is investigated using the relativistic fluid-Maxwell formulation. By adapting the traveling-wave ansatz, three coupled, nonlinear ordinary differential equations are obtained describing the nonlinear propagation of the coupled wave. These equations may be used to study saturation in FELs. By linearizing the nonlinear equations dispersion relations for the traveling wave are obtained. Numerical solution of the small-signal traveling dispersion relation reveals the coupling of radiation to both slow and fast space-charge waves. It is shown that the traveling wave, which is not a normal mode in a laboratory frame, becomes a normal mode in terms of a transformed variable.
On the influence of electromagnetic wave and relativistic electron beam on a plasma
International Nuclear Information System (INIS)
El Ashry, M.Y.; Berezhiani, V.I.; Javakhishvili, J.L.
1993-08-01
The dynamics of nonlinear wave in plasma under the influence of high-frequency electromagnetic pump and relativistic electron beam is considered. It is shown that the electrons of the beam play the role of the heavy plasma component, the matter which creates a possibility of formation of wave of a soliton type in a pure electron plasma. The wave structure is investigated and the characteristic parameters of the soliton are obtained. (author). 8 refs
Research on levitation coupled with standing wave levitation and electromagnetic levitation:
Jiao, Xiao Yang; Li, Xinbo; Liu, GuoJun; Liu, JianFang; Liu, XiaoLun; Lu, Song
2013-01-01
In order to solve the problem caused by metal materials' inability to be cooled without contact with other materials after being heated by electromagnetic levitation, a new method is proposed: using a standing wave levitator to levitate the melted metal. The standing wave levitator adopts a concave spherical surface on the emitter and the reflector. Using ANSYS software, the transducer and the standing wave fields were simulated. Based on the simulation, the distribution and the maximum acous...
International Nuclear Information System (INIS)
de Jong, G.
1975-01-01
With the aid of a two-dimensional integral equation formulation, the ground wave propagation of electromagnetic waves transmitted by a vertical electric dipole over an inhomogeneous flat earth is investigated. For the configuration in which a ground wave is propagating across an ''island'' on a flat earth, the modulus and argument of the attenuation function have been computed. The results for the two-dimensional treatment are significantly more accurate in detail than the calculations using a one-dimensional integral equation
Modulation of a compressional electromagnetic wave in a magnetized electron-positron quantum plasma.
Amin, M R
2015-09-01
Amplitude modulation of a compressional electromagnetic wave in a strongly magnetized electron-positron pair plasma is considered in the quantum magnetohydrodynamic regime. The important ingredients of this study are the inclusion of the external strong magnetic field, Fermi quantum degeneracy pressure, particle exchange potential, quantum diffraction effects via the Bohm potential, and dissipative effect due to collision of the charged carriers. A modified-nonlinear Schödinger equation is developed for the compressional magnetic field of the electromagnetic wave by employing the standard reductive perturbation technique. The linear and nonlinear dispersions of the electromagnetic wave are discussed in detail. For some parameter ranges, relevant to dense astrophysical objects such as the outer layers of white dwarfs, neutron stars, and magnetars, etc., it is found that the compressional electromagnetic wave is modulationally unstable and propagates as a dissipated electromagnetic wave. It is also found that the quantum effects due to the particle exchange potential and the Bohm potential are negligibly small in comparison to the effects of the Fermi quantum degeneracy pressure. The numerical results on the growth rate of the modulation instability is also presented.
Keersmaekers, Lissa; Keustermans, William; De Greef, Daniël; Dirckx, Joris J. J.
2016-06-01
We developed a setup in which the strings of the violin are driven electromagnetically, and the resulting vibration of the instrument is measured with digital stroboscopic holography. A 250mW single mode green laser beam is chopped using an acousto-optic modulator, generating illumination pulses of 2% of the vibration period. The phase of the illumination pulse is controlled by a programmable function generator so that digital holograms can be recorded on a number of subsequent time positions within the vibration phase. From these recordings, the out of plane motion as a function of time is reconstructed in full field. We show results of full-field vibration amplitude and vibration phase maps, and time resolved full-field deformations of the violin back plane. Time resolved measurements show in detail how the deformation of the violin plane changes as a function of time at different frequencies. We found very different behavior under acoustic stimulation of the instrument and when using electromagnetic stimulation of a string. The aim of the work it to gather data which can be used in power flow calculations to study how the energy of the strings is conducted to the body of the violin and eventually is radiated as sound.
International Nuclear Information System (INIS)
Keersmaekers, Lissa; Keustermans, William; De Greef, Daniël; Dirckx, Joris J. J.
2016-01-01
We developed a setup in which the strings of the violin are driven electromagnetically, and the resulting vibration of the instrument is measured with digital stroboscopic holography. A 250 mW single mode green laser beam is chopped using an acousto-optic modulator, generating illumination pulses of 2% of the vibration period. The phase of the illumination pulse is controlled by a programmable function generator so that digital holograms can be recorded on a number of subsequent time positions within the vibration phase. From these recordings, the out of plane motion as a function of time is reconstructed in full field. We show results of full-field vibration amplitude and vibration phase maps, and time resolved full-field deformations of the violin back plane. Time resolved measurements show in detail how the deformation of the violin plane changes as a function of time at different frequencies. We found very different behavior under acoustic stimulation of the instrument and when using electromagnetic stimulation of a string. The aim of the work it to gather data which can be used in power flow calculations to study how the energy of the strings is conducted to the body of the violin and eventually is radiated as sound.
Energy Technology Data Exchange (ETDEWEB)
Keersmaekers, Lissa; Keustermans, William, E-mail: william.keustermans@uantwerpen.be; De Greef, Daniël; Dirckx, Joris J. J. [University of Antwerp, Laboratory of Biophysics and Biomedical Physics, Groenenborgerlaan 171, 2020 Antwerp (Belgium)
2016-06-28
We developed a setup in which the strings of the violin are driven electromagnetically, and the resulting vibration of the instrument is measured with digital stroboscopic holography. A 250 mW single mode green laser beam is chopped using an acousto-optic modulator, generating illumination pulses of 2% of the vibration period. The phase of the illumination pulse is controlled by a programmable function generator so that digital holograms can be recorded on a number of subsequent time positions within the vibration phase. From these recordings, the out of plane motion as a function of time is reconstructed in full field. We show results of full-field vibration amplitude and vibration phase maps, and time resolved full-field deformations of the violin back plane. Time resolved measurements show in detail how the deformation of the violin plane changes as a function of time at different frequencies. We found very different behavior under acoustic stimulation of the instrument and when using electromagnetic stimulation of a string. The aim of the work it to gather data which can be used in power flow calculations to study how the energy of the strings is conducted to the body of the violin and eventually is radiated as sound.
International Nuclear Information System (INIS)
Shvets, G.; Tushentsov, M.; Tokman, M.D.; Kryachko, A.
2005-01-01
Propagation of electromagnetic waves in magnetized plasma near the electron cyclotron frequency can be strongly modified by adding a weak magnetic undulator. For example, both right- and left-hand circularly polarized waves can propagate along the magnetic field without experiencing resonant absorption. This effect of entirely eliminating electron cyclotron heating is referred to as the undulator-induced transparency (UIT) of the plasma, and is the classical equivalent of the well-known quantum mechanical effect of electromagnetically induced transparency. The basics of UIT are reviewed, and various ways in which UIT can be utilized to achieve exotic propagation properties of electromagnetic waves in plasmas are discussed. For example, UIT can dramatically slow down the waves' group velocity, resulting in the extreme compression of the wave energy in the plasma. Compressed waves are polarized along the propagation direction, and can be used for synchronous electron or ion acceleration. Strong coupling between the two wave helicities are explored to impart the waves with high group velocities ∂ω/∂k for vanishing wave numbers k. Cross-helicity coupling for realistic density and magnetic field profiles are examined using a linearized fluid code, particle-in-cell simulations, and ray-tracing WKB calculations
Attenuation bands and cut-off frequencies for ELF electromagnetic waves
International Nuclear Information System (INIS)
Rauch, J.L.; Lefeuvre, F.; Cerisier, J.C.; Berthelier, J.J.; Boud'ko, N.; Michailova, G.; Kapustina, O.
1985-01-01
The propagation characteristic of ELF (10 Hz - 1500 Hz) electromagnetic waves observed on ARCAD 3, in three different zones: low L value (L 6). Unambiguous determinations of the wave normal directions are obtained from the interpretations of the measurements of four (3 magnetic, 1 electric) wave field components. The technique that is used, is based on the Means method in the cases of highly polarized waves and on the Storey and Lefeuvre WDF method in the other cases. A particular emphasis is put on the propagation characteristics of the waves, in a multiple ion plasma, and on the cut-off frequencies which appear at and below the local proton gyrofrequency
Speed of Gravitational Waves from Strongly Lensed Gravitational Waves and Electromagnetic Signals.
Fan, Xi-Long; Liao, Kai; Biesiada, Marek; Piórkowska-Kurpas, Aleksandra; Zhu, Zong-Hong
2017-03-03
We propose a new model-independent measurement strategy for the propagation speed of gravitational waves (GWs) based on strongly lensed GWs and their electromagnetic (EM) counterparts. This can be done in two ways: by comparing arrival times of GWs and their EM counterparts and by comparing the time delays between images seen in GWs and their EM counterparts. The lensed GW-EM event is perhaps the best way to identify an EM counterpart. Conceptually, this method does not rely on any specific theory of massive gravitons or modified gravity. Its differential setting (i.e., measuring the difference between time delays in GW and EM domains) makes it robust against lens modeling details (photons and GWs travel in the same lensing potential) and against internal time delays between GW and EM emission acts. It requires, however, that the theory of gravity is metric and predicts gravitational lensing similar to general relativity. We expect that such a test will become possible in the era of third-generation gravitational-wave detectors, when about 10 lensed GW events would be observed each year. The power of this method is mainly limited by the timing accuracy of the EM counterpart, which for kilonovae is around 10^{4} s. This uncertainty can be suppressed by a factor of ∼10^{10}, if strongly lensed transients of much shorter duration associated with the GW event can be identified. Candidates for such short transients include short γ-ray bursts and fast radio bursts.
Population of vibrational levels of carbon dioxide by cylindrical fast ionization wave
Levko, Dmitry
2017-09-08
The population of vibrational levels of carbon dioxide (CO2) by a cylindrical fast ionization wave is analyzed using a one-dimensional Particle-in-Cell Monte Carlo collisions model. The model takes into account the inelastic electron-neutral collisions as well as the super-elastic collisions between electrons and excited species. We observe an efficient population of only the first two levels of the symmetric and asymmetric vibrational modes of CO2 by means of a fast ionization wave. The excitation of other higher vibrational modes by the fast ionization wave is inefficient. Additionally, we observe a strong influence of the secondary electron emission on the population of vibrational states of CO2. This effect is associated with the kinetics of high energy electrons generated in the cathode sheath.
Simoes, Fernando; Pfaff, Robert; Berthelier, Jean-Jacques; Klenzing, Jeffrey
2012-01-01
Investigation of coupling mechanisms between the troposphere and the ionosphere requires a multidisciplinary approach involving several branches of atmospheric sciences, from meteorology, atmospheric chemistry, and fulminology to aeronomy, plasma physics, and space weather. In this work, we review low frequency electromagnetic wave propagation in the Earth-ionosphere cavity from a troposphere-ionosphere coupling perspective. We discuss electromagnetic wave generation, propagation, and resonance phenomena, considering atmospheric, ionospheric and magnetospheric sources, from lightning and transient luminous events at low altitude to Alfven waves and particle precipitation related to solar and magnetospheric processes. We review in situ ionospheric processes as well as surface and space weather phenomena that drive troposphere-ionosphere dynamics. Effects of aerosols, water vapor distribution, thermodynamic parameters, and cloud charge separation and electrification processes on atmospheric electricity and electromagnetic waves are reviewed. We also briefly revisit ionospheric irregularities such as spread-F and explosive spread-F, sporadic-E, traveling ionospheric disturbances, Trimpi effect, and hiss and plasma turbulence. Regarding the role of the lower boundary of the cavity, we review transient surface phenomena, including seismic activity, earthquakes, volcanic processes and dust electrification. The role of surface and atmospheric gravity waves in ionospheric dynamics is also briefly addressed. We summarize analytical and numerical tools and techniques to model low frequency electromagnetic wave propagation and solving inverse problems and summarize in a final section a few challenging subjects that are important for a better understanding of tropospheric-ionospheric coupling mechanisms.
Birefringence induced by pp-wave modes in an electromagnetically active dynamic aether
International Nuclear Information System (INIS)
Alpin, Timur Yu.; Balakin, Alexander B.
2017-01-01
In the framework of the Einstein-Maxwell-aether theory we study the birefringence effect, which can occur in the pp-wave symmetric dynamic aether. The dynamic aether is considered to be a latently birefringent quasi-medium, which displays this hidden property if and only if the aether motion is non-uniform, i.e., when the aether flow is characterized by the non-vanishing expansion, shear, vorticity or acceleration. In accordance with the dynamo-optical scheme of description of the interaction between electromagnetic waves and the dynamic aether, we shall model the susceptibility tensors by the terms linear in the covariant derivative of the aether velocity four-vector. When the pp-wave modes appear in the dynamic aether, we deal with a gravitationally induced degeneracy removal with respect to hidden susceptibility parameters. As a consequence, the phase velocities of electromagnetic waves possessing orthogonal polarizations do not coincide, thus displaying the birefringence effect. Two electromagnetic field configurations are studied in detail: longitudinal and transversal with respect to the aether pp-wave front. For both cases the solutions are found, which reveal anomalies in the electromagnetic response on the action of the pp-wave aether mode. (orig.)
Birefringence induced by pp-wave modes in an electromagnetically active dynamic aether
Energy Technology Data Exchange (ETDEWEB)
Alpin, Timur Yu.; Balakin, Alexander B. [Kazan Federal University, Department of General Relativity and Gravitation, Institute of Physics, Kazan (Russian Federation)
2017-10-15
In the framework of the Einstein-Maxwell-aether theory we study the birefringence effect, which can occur in the pp-wave symmetric dynamic aether. The dynamic aether is considered to be a latently birefringent quasi-medium, which displays this hidden property if and only if the aether motion is non-uniform, i.e., when the aether flow is characterized by the non-vanishing expansion, shear, vorticity or acceleration. In accordance with the dynamo-optical scheme of description of the interaction between electromagnetic waves and the dynamic aether, we shall model the susceptibility tensors by the terms linear in the covariant derivative of the aether velocity four-vector. When the pp-wave modes appear in the dynamic aether, we deal with a gravitationally induced degeneracy removal with respect to hidden susceptibility parameters. As a consequence, the phase velocities of electromagnetic waves possessing orthogonal polarizations do not coincide, thus displaying the birefringence effect. Two electromagnetic field configurations are studied in detail: longitudinal and transversal with respect to the aether pp-wave front. For both cases the solutions are found, which reveal anomalies in the electromagnetic response on the action of the pp-wave aether mode. (orig.)
Vafin, S.; Schlickeiser, R.; Yoon, P. H.
2016-05-01
The general electromagnetic fluctuation theory for magnetized plasmas is used to calculate the steady-state wave number spectra and total electromagnetic field strength of low-frequency collective weakly damped eigenmodes with parallel wavevectors in a Maxwellian electron-proton plasma. These result from the equilibrium of spontaneous emission and collisionless damping, and they represent the minimum electromagnetic fluctuations guaranteed in quiet thermal space plasmas, including the interstellar and interplanetary medium. Depending on the plasma beta, the ratio of |δB |/B0 can be as high as 10-12 .
Electromagnetic Ion Cyclotron Waves Detected by Kaguya and Geotail in the Earth's Magnetotail
Nakagawa, Tomoko; Nishino, Masaki N.; Tsunakawa, Hideo; Takahashi, Futoshi; Shibuya, Hidetoshi; Shimizu, Hisayoshi; Matsushima, Masaki; Saito, Yoshifumi
2018-02-01
Narrowband electromagnetic ion cyclotron waves first discovered by the Apollo 15 and 16 Lunar Surface Magnetometers were surveyed in the magnetic field data obtained by the Kaguya satellite at an altitude of ˜100 km above the Moon in the tail lobe and plasma sheet boundary layer of the Earth's magnetosphere. The frequencies of the waves were typically 0.7 times the local proton cyclotron frequency, and 75% of the waves were left hand polarized with respect to the background magnetic field. They had a significant compressional component and comprised several discrete packets. They were detected on the dayside, nightside, and above the terminator of the Moon, irrespective of the lunar magnetic anomaly, or the magnetic connection to the lunar surface. The waves with the same characteristics were detected by Geotail in the absence of the Moon in the magnetotail. The most likely energy source of the electromagnetic ion cyclotron waves is the ring beam ions in the plasma sheet boundary layer.
Multiphoton processes in the field of two-frequency circularly polarized plane electromagnetic waves
International Nuclear Information System (INIS)
Yu, An
1997-01-01
The authors solve Dirac's equation for an electron in the field of a two-frequency plane electromagnetic wave, deriving general formulae for the probabilities of radiation of a photon by the electron, and for the probabilities for pair production by a photon when the two-frequency wave is circularly polarized. In contrast to the case of a monochromatic-plane electromagnetic wave, when an electron is in the field of a two-frequency circularly polarized wave, besides the absorption of multiphotons and emission of simple harmonics of the individual waves, stimulated multiphoton emission processes and various composite harmonic-photon emission processes are occurred: when a high-energy photon is in a such a field, multiphoton processes also follow the pair production processes
Theory of reflection reflection and transmission of electromagnetic, particle and acoustic waves
Lekner, John
2016-01-01
This book deals with the reflection of electromagnetic and particle waves by interfaces. The interfaces can be sharp or diffuse. The topics of the book contain absorption, inverse problems, anisotropy, pulses and finite beams, rough surfaces, matrix methods, numerical methods, reflection of particle waves and neutron reflection. Exact general results are presented, followed by long wave reflection, variational theory, reflection amplitude equations of the Riccati type, and reflection of short waves. The Second Edition of the Theory of Reflection is an updated and much enlarged revision of the 1987 monograph. There are new chapters on periodically stratified media, ellipsometry, chiral media, neutron reflection and reflection of acoustic waves. The chapter on anisotropy is much extended, with a complete treatment of the reflection and transmission properties of arbitrarily oriented uniaxial crystals. The book gives a systematic and unified treatment reflection and transmission of electromagnetic and particle...
International Nuclear Information System (INIS)
Kim, Se Yun
2009-01-01
This book deals with engineering electromagnetics. It contains seven chapters, which treats understanding of engineering electromagnetics such as magnet and electron spin, current and a magnetic field and an electromagnetic wave, Essential tool for engineering electromagnetics on rector and scalar, rectangular coordinate system and curl vector, electrostatic field with coulomb rule and method of electric images, Biot-Savart law, Ampere law and magnetic force, Maxwell equation and an electromagnetic wave and reflection and penetration of electromagnetic plane wave.
Transversality of electromagnetic waves in the calculus-based introductory physics course
International Nuclear Information System (INIS)
Burko, Lior M
2008-01-01
Introductory calculus-based physics textbooks state that electromagnetic waves are transverse and list many of their properties, but most such textbooks do not bring forth arguments why this is so. Both physical and theoretical arguments are at a level appropriate for students of courses based on such books, and could be readily used by instructors of such courses. Here, we discuss two physical arguments (based on polarization experiments and on lack of monopole electromagnetic radiation) and the full argument for the transversality of (plane) electromagnetic waves based on the integral Maxwell equations. We also show, at a level appropriate for the introductory course, why the electric and magnetic fields in a wave are in phase and the relation of their magnitudes
Influence of Sea Surface Roughness on the Electromagnetic Wave Propagation in the Duct Environment
Directory of Open Access Journals (Sweden)
X. Zhao
2010-12-01
Full Text Available This paper deals with a study of the influence of sea surface roughness on the electromagnetic wave propagation in the duct environment. The problem of electromagnetic wave propagation is modeled by using the parabolic equation method. The roughness of the sea surface is computed by modifying the smooth surface Fresnel reflection coefficient to account for the reduction in the specular reflection due to the roughness resulting from sea wind speed. The propagation model is solved by the mixed Fourier split-step algorithm. Numerical experiments indicate that wind-driven roughened sea surface has an impact on the electromagnetic wave propagation in the duct environment, and the strength is intensified along with the increment of sea wind speeds and/or the operating frequencies. In a fixed duct environment, however, proper disposition of the transmitter could reduce these impacts.
Transversality of electromagnetic waves in the calculus-based introductory physics course
Burko, Lior M.
2008-11-01
Introductory calculus-based physics textbooks state that electromagnetic waves are transverse and list many of their properties, but most such textbooks do not bring forth arguments why this is so. Both physical and theoretical arguments are at a level appropriate for students of courses based on such books, and could be readily used by instructors of such courses. Here, we discuss two physical arguments (based on polarization experiments and on lack of monopole electromagnetic radiation) and the full argument for the transversality of (plane) electromagnetic waves based on the integral Maxwell equations. We also show, at a level appropriate for the introductory course, why the electric and magnetic fields in a wave are in phase and the relation of their magnitudes.
Transversality of Electromagnetic Waves in the Calculus--Based Introductory Physics Course
Burko, Lior M.
2009-05-01
Introductory calculus--based physics textbooks state that electromagnetic waves are transverse and list many of their properties, but most such textbooks do not bring forth arguments why this is so. Both physical and theoretical arguments are at a level appropriate for students of courses based on such books, and could be readily used by instructors of such courses. Here, we discuss two physical arguments (based on polarization experiments and on lack of monopole electromagnetic radiation), and the full argument for the transversality of (plane) electromagnetic waves based on the integral Maxwell equations. We also show, at a level appropriate for the introductory course, why the electric and magnetic fields in a wave are in phase and the relation of their magnitudes. We have successfully integrated this approach in the calculus--based introductory physics course at the University of Alabama in Huntsville.
Parametric study of electromagnetic waves propagating in absorbing curved S ducts
Baumeister, Kenneth J.
1989-01-01
A finite-element Galerkin formulation has been developed to study attenuation of transverse magnetic (TM) waves propagating in two-dimensional S-curved ducts with absorbing walls. In the frequency range where the duct diameter and electromagnetic wave length are nearly equal, the effect of duct length, curvature (duct offset), and absorber wall thickness was examined. For a given offset in the curved duct, the length of the S-duct was found to significantly affect both the absorptive and reflective characteristics of the duct. For a straight and a curved duct with perfect electric conductor terminations, power attenuation contours were examined to determine electromagnetic wall properties associated with maximum input signal absorption. Offset of the S-duct was found to significantly affect the value of the wall permittivity associated with the optimal attenuation of the incident electromagnetic wave.
On the possibility of the autoresonant motion of an electron in a slow electromagnetic wave
International Nuclear Information System (INIS)
Milantiev, V.P.
1994-01-01
By autoresonant motion one usually means the motion when the condition of cyclotron resonance of gyrating particle with electromagnetic wave is conserved during all the time of the motion in spite of the relativistic mass increase. Such a motion takes place only in the case of vacuum wave, when the phase velocity ν p is equal to the speed of light in a vacuum C. Otherwise autoresonance is impossible, and energy of the particle oscillates in time. The authors now discuss the possibility of the autoresonance in a slow electromagnetic wave (ν p < c) propagating along the straight lines of the external magnetic field. It turns out that the autoresonant regime of the motion in a slow electromagnetic wave possible if some rather restrictive relations between the electric drift velocity and the phase velocity of wave take place. It depends also on the polarization of wave. The general case of the elliptical polarization is considered. The optimal regime corresponds to the wave with linear polarization in the direction of the constant electric field. For this case the calculations show that energy of the particle can unlimitedly increase (or decrease). The rate of acceleration can be even larger than in the case of vacuum wave. Radiation forces will restrict this process
Nonstationary self-action of electromagnetic wave beams in the beat accelerator
International Nuclear Information System (INIS)
Abramyan, L.A.; Litvak, A.G.; Mironov, V.A.
1990-01-01
The resonance excitation of a plasma wave in a modified accelerator using the beats of two electromagnetic waves permits to increase considerably the intensity of the accelerating field and, consequently, the rate of the accumulation of the energy by charged particles. The efficiency of the electromagnetic radiation conversion to the longitudinal wave is defined by nonlinear processes. The saturation of the accelerating field is considered which is due to the appearance of multiflux motion of electrons oscillating in the wave field with overturn of waves, due to the development of parametric instabilities and due to the change of natural frequency of plasma oscillations caused by the relativistic increase of electron mass. The effects of self-action which change the form of the electromagnetic radiation pulse and the wave beam structure play a significant role in the most promising laser plasma beat accelerator. We consider dynamics of space distribution of the plasma wave in a self-consistent field of the wave beam. (author) 5 refs., 2 figs
On the generation of electromagnetic waves in the terahertz frequency range
International Nuclear Information System (INIS)
Namiot, V.A.; Shchurova, L.Yu.
2011-01-01
It is shown that a thin dielectric plate, which can act as an open dielectric waveguide, it is possible to produce amplification and generation of electromagnetic waves with frequencies in the terahertz range. For this purpose, we propose using a dielectric plate with a corrugated surface, in which case the electric field of the transverse electromagnetic wave in the waveguide has a periodic spatial structure in the local area near to the corrugation. Terahertz electromagnetic waves are excited by a beam of electrons moving in vacuum along the dielectric plate at a small distance from its corrugated surface. Corrugation period is chosen in order to ensure the most effective interaction of the electron beam with the first harmonic of the electric field induced by the corrugation. Amplification and generation of electromagnetic waves propagating in a dielectric waveguide is realized as a result of deceleration of the electron beam by a wave electric field induced by a corrugated dielectric surface in the zone near the corrugation. We discuss possible ways to create electron beams with the desired characteristics. We offer a way to stabilize the beam position above the plate, avoiding the bombardment of the plate by electrons. It is shown that it is possible to significantly increase the efficiency of the device through the recovery of energy that remains in the electrons after their interaction with the wave. -- Highlights: → We propose a scheme of a generator of radio waves in the terahertz range. → This scheme includes a corrugated dielectric plate, which can act as an open waveguide. → A strip electron beam is in vacuum near the dielectric corrugated surface. → Generation is achieved by converting electrons' energy into electromagnetic energy. → The waveguide wave extends perpendicularly to electron motion.
Study on the electromagnetic waves propagation characteristics in partially ionized plasma slabs
Directory of Open Access Journals (Sweden)
Zhi-Bin Wang
2016-05-01
Full Text Available Propagation characteristics of electromagnetic (EM waves in partially ionized plasma slabs are studied in this paper. Such features are significant to applications in plasma antennas, blackout of re-entry flying vehicles, wave energy injection to plasmas, and etc. We in this paper developed a theoretical model of EM wave propagation perpendicular to a plasma slab with a one-dimensional density inhomogeneity along propagation direction to investigate essential characteristics of EM wave propagation in nonuniform plasmas. Particularly, the EM wave propagation in sub-wavelength plasma slabs, where the geometric optics approximation fails, is studied and in comparison with thicker slabs where the geometric optics approximation applies. The influences of both plasma and collisional frequencies, as well as the width of the plasma slab, on the EM wave propagation characteristics are discussed. The results can help the further understanding of propagation behaviours of EM waves in nonuniform plasma, and applications of the interactions between EM waves and plasmas.
Artemyev, A V; Neishtadt, A I; Zelenyi, L M; Vainchtein, D L
2010-12-01
We present an analytical and numerical study of the surfatron acceleration of nonrelativistic charged particles by electromagnetic waves. The acceleration is caused by capture of particles into resonance with one of the waves. We investigate capture for systems with one or two waves and provide conditions under which the obtained results can be applied to systems with more than two waves. In the case of a single wave, the once captured particles never leave the resonance and their velocity grows linearly with time. However, if there are two waves in the system, the upper bound of the energy gain may exist and we find the analytical value of that bound. We discuss several generalizations including the relativistic limit, different wave amplitudes, and a wide range of the waves' wavenumbers. The obtained results are used for qualitative description of some phenomena observed in the Earth's magnetosphere. © 2010 American Institute of Physics.
Laumal, F. E.; Nope, K. B. N.; Peli, Y. S.
2018-01-01
Early warning is a warning mechanism before an actual incident occurs, can be implemented on natural events such as tsunamis or earthquakes. Earthquakes are classified in tectonic and volcanic types depend on the source and nature. The tremor in the form of energy propagates in all directions as Primary and Secondary waves. Primary wave as initial earthquake vibrations propagates longitudinally, while the secondary wave propagates like as a sinusoidal wave after Primary, destructive and as a real earthquake. To process the primary vibration data captured by the earthquake sensor, a network management required client computer to receives primary data from sensors, authenticate and forward to a server computer to set up an early warning system. With the water propagation concept, a method of early warning system has been determined in which some sensors are located on the same line, sending initial vibrations as primary data on the same scale and the server recommended to the alarm sound as an early warning.
influence of electromagnetic waves produced by an amplitude
African Journals Online (AJOL)
PROF EKWUEME
m. 10 . The magnetotransport and continuity equations of excess minority carriers are solved with boundary conditions and led to new analytical expressions of minority carrier's density, photocurrent density, photovoltage and electric power depending on electromagnetic field intensity and wavelength λ. The dependence of.
Influence of electromagnetic waves produced by an amplitude ...
African Journals Online (AJOL)
The magnetotransport and continuity equations of excess minority carriers are solved with boundary conditions and led to new analytical expressions of minority carrier's density, photocurrent density, photovoltage and electric power depending on electromagnetic field intensity and wavelength λ. The dependence of the ...
Breathers in Josephson junction ladders: Resonances and electromagnetic wave spectroscopy
DEFF Research Database (Denmark)
Miroshnichenko, A. E.; Flach, S.; Fistul, M.
2001-01-01
We present a theoretical study of the resonant interaction between dynamical localized states (discrete breathers) and linear electromagnetic excitations (EE's) in Josephson junction ladders. By making use of direct numerical simulations we find that such an interaction manifests itself by resonant...
International Nuclear Information System (INIS)
Uluşan, H; Gharehbaghi, K; Külah, H; Zorlu, Ö; Muhtaroğlu, A
2015-01-01
This study presents a novel hybrid system that combines the power generated simultaneously by a vibration-based Electromagnetic (EM) harvester and a UHF band RF harvester. The novel hybrid scavenger interface uses a power management circuit in 180 nm CMOS technology to step-up and to regulate the combined output. At the first stage of the system, the RF harvester generates positive DC output with a 7-stage threshold compensated rectifier, while the EM harvester generates negative DC output with a self-powered AC/DC negative doubler circuit. At the second stage, the generated voltages are serially added, stepped-up with an on-chip charge pump circuit, and regulated to a typical battery voltage of 3 V. Test results indicate that the hybrid operation enables generation of 9 μW at 3 V output for a wide range of input stimulations, which could not be attained with either harvesting mode by itself. Moreover the hybrid system behaves as a typical battery, and keeps the output voltage stable at 3 V up to 18 μW of output power. The presented system is the first battery-like harvester to our knowledge that generates energy from two independent sources and regulates the output to a stable DC voltage. (paper)
Brewster angle for an E-polarized electromagnetic wave interacting with a moving dielectric medium
International Nuclear Information System (INIS)
Mukherjee, P.K.
1977-01-01
The Brewster-angle phenomena of total transmission has been investigated with reference to an E-polarized electromagnetic wave interacting with a dielectric half-space moving along the interface. Analytic conditions are derived for the existence of Brewster angles. We also discuss how the Brewster angles are modified by replacing the incident region (in which the incident electromagnetic wave is propagated) with an isotropic or a uniaxially anisotropic plasma. The Brewster angles are found to behave in a remarkably different fashion under various conditions. Numerical results for the Brewster angles, showing their dependence on the nondimensional velocity of the medium β, are presented for several values of the physical parameters
International Nuclear Information System (INIS)
Shapiro, B.Y.
1992-01-01
The behavior of a superconductor in time-independent electric field perpendicular to the surface and in the external electromagnetic wave is theoretically investigated. A new type of the resonance interaction between superconducting domains localized along the magnetic field (if the superconducting phase transition takes place in the external magnetic field perpendicular to the surface) and electromagnetic waves is predicted. The surface impedance of the superconductor with domains is calculated. It is shown that the real part of the impedance has a saturation if the skin length equals the domain size. (orig.)
International Nuclear Information System (INIS)
Pogorel'tsev, A.I.; Bidlingmajer, E.R.
1992-01-01
A numeric model of electromagnetic field disturbances generated under the interaction of acoustic-gravitational waves with ionospheric plasma is elaborated and vertical structure of the above disturbances is calculated. The estimates shown that electromagnetic disturbances can penetrate into neutral atmosphere and can be recorded through measurements of the variation of magnetic field and electron field vertical component near the earth is surface. A conclusion is made on a feasibility of monitoring of acoustic-gravitational wave activity in the lower thermosphere through land measurements of magnetic and electric field variations
A theoretical study of hot plasma spheroids in the presence of low-frequency electromagnetic waves
Ahmadizadeh, Y.; Jazi, B.; Barjesteh, S.
2016-07-01
While taking into account thermal motion of electrons, scattering of electromagnetic waves with low frequency from hot plasma spheroids is investigated. In this theoretical research, ions are heavy to respond to electromagnetic fluctuations. The solution of scalar wave equation in spheroidal coordinates for electric potential inside the plasma spheroids are obtained. The variations of resonance frequencies vs. Debye length are studied and consistency between the obtained results in this paper and the results for the well-known plasma objects such as plasma column and spherical plasma have been proved.
International Nuclear Information System (INIS)
Akoev, G.N.; Avelev, V.D.
1995-01-01
Low intensity millimeter-wave electromagnetic radiation of less than 10 mW cm -2 power intensity has a nonthermal effect on the body and it is widely used in medical practice for treatment of various diseases. Nevertheless, the effect of EMR on biological tissues is not understood. The skin and its sensory receptors are considered to be responsible for EMR reception, but this has yet to be confirmed. The present experiments were designed to study the effect of millimeter-wave electromagnetic radiation on the ampullae of Lorenzini in skates, which are very sensitive to weak electrical stimuli at low frequency. (author)
WKB solution 4×4 for electromagnetic waves in a planar magnetically anisotropic inhomogeneous layer
Moiseeva, Natalya Michailovna; Moiseev, Anton Vladimirovich
2018-04-01
In the paper, an oblique incidence of a plane electromagnetic wave on a planar magnetically anisotropic inhomogeneous layer is considered. We consider the case when all the components of the magnetic permeability tensor are non zero and vary with distance from the interface of media. The WKB method gives a matrix 4 × 4 solution for the projections of the electromagnetic wave fields during its propagation. The dependence of the cross-polarized components on the orientation of the anisotropic medium relative to the plane of incidence of the medium is analyzed.
Li, Jia; Wu, Pinghui; Chang, Liping
2015-08-24
Within the accuracy of the first-order Born approximation, sufficient conditions are derived for the invariance of spectrum of an electromagnetic wave, which is generated by the scattering of an electromagnetic plane wave from an anisotropic random media. We show that the following restrictions on properties of incident fields and the anisotropic media must be simultaneously satisfied: 1) the elements of the dielectric susceptibility matrix of the media must obey the scaling law; 2) the spectral components of the incident field are proportional to each other; 3) the second moments of the elements of the dielectric susceptibility matrix of the media are inversely proportional to the frequency.
International Nuclear Information System (INIS)
Davidovich, Mikhail V
2009-01-01
Some paradoxes are discussed concerning the interpretation of the passage of particles and electromagnetic waves (pulses) across potential barriers and through nonuniform media, in particular, those with frequency dispersion and therefore dissipation. It is emphasized that a rigorous nonstationary approach does not entail any supraluminal velocities for the transfer of physical substances, although supraluminal velocities are indeed possible for several kinematically defined velocities, e.g., for the group velocity. (letters to the editors)
Electromagnetic mode conversion: understanding waves that suddenly change their nature
International Nuclear Information System (INIS)
Batchelor, D B; Berry, L A; Bonoli, P T; Carter, M D; Choi, M; D'Azevedo, E; D'Ippolito, D A; Gorelenkov, N; Harvey, R W; Jaeger, E F; Myra, J R; Okuda, H; Phillips, C K; Smithe, D N; Wright, J C
2005-01-01
In a magnetized plasma, such as in fusion devices or the Earth's magnetosphere, several different kinds of waves can simultaneously exist, having very different physical properties. Under the right conditions one wave can quite suddenly convert to another type. Depending on the case, this can be either a great benefit or a problem for the use of waves to heat and control fusion plasmas. Understanding and accurately modeling such behavior is a major computational challenge
Mathieu functions describing particles evolving in electromagnetic waves
Mihu, Denisa-Andreea; Dariescu, Marina-Aura
2017-12-01
Solutions of Klein-Gordon equation for particles moving in a standing wave configuration bring into attention an intricate and complicated category of special functions, namely the Mathieu functions. The stability of the solutions governed by the intercorrelation between Mathieu equation' parameters is discussed. For specific intervals of the wave number, the instability regime installs, pointing out the tendency of exponential growth for the oscillatory wave functions, as a consequence of parametric resonance phenomenon. The expression of the wave function allows the computation of the four-dimensional conserved current density components.
Simulation study on cross polarization scattering of ultrashort-pulse electromagnetic waves
International Nuclear Information System (INIS)
Katsuragawa, Naoki; Hojo, Hitoshi; Mase, Atushi
1996-11-01
Simulation study on cross polarization scattering of ultrashort-pulse electromagnetic waves due to magnetic fluctuations is presented. One-dimensional coupled wave equations for the ordinary and extraordinary modes are solved for incident unipolar sub-cycle pulses in an inhomogeneous magnetized plasma. It is shown that the peak frequencies in the frequency-spectral signals of the mode-converted reflected waves are determined from the Bragg resonance condition in the wave numbers of the ordinary mode, the extraordinary mode and the magnetic fluctuations for relatively short-wavelength localized magnetic fluctuations. (author)
Excitation of plasma waves by nonlinear currents induced by a high-frequency electromagnetic pulse
Energy Technology Data Exchange (ETDEWEB)
Grishkov, V. E.; Uryupin, S. A., E-mail: uryupin@sci.lebedev.ru [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation)
2017-03-15
Excitation of plasma waves by nonlinear currents induced by a high-frequency electromagnetic pulse is analyzed within the kinetic approach. It is shown that the most efficient source of plasma waves is the nonlinear current arising due to the gradient of the energy density of the high-frequency field. Generation of plasma waves by the drag current is usually less efficient but not negligibly small at relatively high frequencies of electron–ion collisions. The influence of electron collisions on the excitation of plasma waves by pulses of different duration is described quantitatively.
Anisotropic effects of background fields on Born-Infeld electromagnetic waves
International Nuclear Information System (INIS)
Aiello, Matias; Bengochea, Gabriel R.; Ferraro, Rafael
2007-01-01
We show exact solutions of the Born-Infeld theory for electromagnetic plane waves propagating in the presence of static background fields. The non-linear character of the Born-Infeld equations generates an interaction between the background and the wave that changes the speed of propagation and adds a longitudinal component to the wave. As a consequence, in a magnetic background the ray direction differs from the propagation direction-a behavior resembling the one of a wave in an anisotropic medium. This feature could open up a way to experimental tests of the Born-Infeld theory
International Nuclear Information System (INIS)
Maraghechi, B.; Willett, J.e.
1979-01-01
The stimulated Raman backscattering of an intense electromagnetic wave propagating in the extraordinary mode along a uniform, static magnetic field is considered. The dispersion relation for a homogeneous magnetized plasma in the presence of the circularly polarized pump waves is developed in the cold-plasma approximation with the pump frequency above the plasma frequency. Formulas are derived for the threshold νsub(OT) of the parametric instability and for the growth rate γ of the backscattered extraordinary wave and Langmuir wave. The effects of the magnetic field parallel to the direction of propagation on νsub(0T) and γ are studied numerically. (author)
Anisotropic effects of background fields on Born-Infeld electromagnetic waves
Energy Technology Data Exchange (ETDEWEB)
Aiello, Matias [Instituto de Astronomia y Fisica del Espacio, Casilla de Correo 67, Sucursal 28, 1428 Buenos Aires (Argentina) and Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellon I, 1428 Buenos Aires (Argentina)]. E-mail: aiello@iafe.uba.ar; Bengochea, Gabriel R. [Instituto de Astronomia y Fisica del Espacio, Casilla de Correo 67, Sucursal 28, 1428 Buenos Aires (Argentina) and Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellon I, 1428 Buenos Aires (Argentina)]. E-mail: gabriel@iafe.uba.ar; Ferraro, Rafael [Instituto de Astronomia y Fisica del Espacio, Casilla de Correo 67, Sucursal 28, 1428 Buenos Aires (Argentina) and Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellon I, 1428 Buenos Aires (Argentina)]. E-mail: ferraro@iafe.uba.ar
2007-01-22
We show exact solutions of the Born-Infeld theory for electromagnetic plane waves propagating in the presence of static background fields. The non-linear character of the Born-Infeld equations generates an interaction between the background and the wave that changes the speed of propagation and adds a longitudinal component to the wave. As a consequence, in a magnetic background the ray direction differs from the propagation direction-a behavior resembling the one of a wave in an anisotropic medium. This feature could open up a way to experimental tests of the Born-Infeld theory.
Scattering of electromagnetic waves by anomalous fluctuations of a magnetized plasma
Pavlenko, V. N.; Panchenko, V. G.
1990-04-01
Fluctuations and scattering of transverse electromagnetic waves by density fluctuations in a magnetized plasma in the presence of parametric decay of the pump wave are investigated. The spectral density of electron-density fluctuations is calculated. It is shown that the differential scattering cross-section has sharp maxima at the ion-acoustic and lower-hybrid frequencies when parametric decay of the lower-hybrid pump wave occurs. We note that scattering at the ion-acoustic frequency is dominant. When the pump-wave amplitude tends to the threshold strength of the electric field the scattering cross-section increases anomalously, i.e. there is critical opalescence.
International Nuclear Information System (INIS)
Saito, Yukimasa
1977-01-01
The transient reflection and transmission waves of E polarized electromagnetic waves coming into the boundary surface between air and moving isotropic plasma were theoretically investigated. By using the Laplace transformation in the moving system, the formulae of Lorentz and inverse Lorentz transformations concerning electromagnetic field were transformed, thus the transient reflection and transmission waves were obtained. These waves were normalized with the angular frequency of the incident waves, and the variation of the wave form was obtained. Examples of the numerical calculation of reflected waves are shown for the plasma moving in parallel to the boundary surface. (Kato, T.)
Analysis of wave equation in electromagnetic field by Proca equation
International Nuclear Information System (INIS)
Pamungkas, Oky Rio; Soeparmi; Cari
2017-01-01
This research is aimed to analyze wave equation for the electric and magnetic field, vector and scalar potential, and continuity equation using Proca equation. Then, also analyze comparison of the solution on Maxwell and Proca equation for scalar potential and electric field, both as a function of distance and constant wave number. (paper)
[INVITED] Coherent perfect absorption of electromagnetic wave in subwavelength structures
Yan, Chao; Pu, Mingbo; Luo, Jun; Huang, Yijia; Li, Xiong; Ma, Xiaoliang; Luo, Xiangang
2018-05-01
Electromagnetic (EM) absorption is a common process by which the EM energy is transformed into other kinds of energy in the absorber, for example heat. Perfect absorption of EM with structures at subwavelength scale is important for many practical applications, such as stealth technology, thermal control and sensing. Coherent perfect absorption arises from the interplay of interference and absorption, which can be interpreted as a time-reversed process of lasing or EM emitting. It provides a promising way for complete absorption in both nanophotonics and electromagnetics. In this review, we discuss basic principles and properties of a coherent perfect absorber (CPA). Various subwavelength structures including thin films, metamaterials and waveguide-based structures to realize CPAs are compared. We also discuss the potential applications of CPAs.
Xiaoxing Zhang; Guozhi Zhang; Yalong Li; Jian Zhang; Rui Huang
2017-01-01
This study analyzed the transformer electromagnetic gap propagation characteristics. The influence of gap size is also analyzed, and the results experimentally verified. The obtained results indicated that the gap propagation characteristics of electromagnetic wave signals radiated by the partial discharge (PD) source in different directions are substantially different. The intensity of the electromagnetic wave in the gap reaches a maximum at a gap height of 1 cm; and inside the gap, the inte...
Absorption of Electro-magnetic Waves in a Magnetized Medium
Ganguly, Avijit K.; Konar, Sushan
2000-01-01
In continuation to our earlier work, in which the structure of the vacuum polarisation tensor in a medium was analysed in presence of a background electro-magnetic field, we discuss the absorptive part of the vacuum polarization tensor. Using the real time formalism of finite temperature field theory we calculate the absorptive part of 1-loop vacuum polarisation tensor in the weak field limit ($eB < m^2$). Estimates of the absorption probability are also made for different physical conditions...
Propagation Characteristics of Electromagnetic Waves Recorded by the Four CLUSTER Satellites
International Nuclear Information System (INIS)
Parrot, M.; Santolik, O.; Cornilleau-Wehrlin, N.; Maksimovic, M.; Harvey, Ch.
2001-01-01
This paper will describe the methods we use to determine the propagation characteristics of electromagnetic waves observed by the four CLUSTER satellites. The data is recorded aboard CLUSTER by the STAFF (Spatio-Temporal Analysis of Field Fluctuations) spectrum analyser. This instrument has several modes of operation, and can provide the spectral matrix of three magnetic and two electric components. This spectral matrix is processed by a dedicated software (PRASSADCO: Propagation Analysis of STAFF-SA Data with Coherency Tests) in order to determine the wave normal directions with respect to the DC magnetic field. PRASSADCO also provides a number of alternative methods to estimate wave polarisation and propagation parameters, such as the Poynting vector, and the refractive index. It is therefore possible to detect the source extension of various electromagnetic waves using the 4 satellites. Results of this data processing will be shown here for one event observed by one satellite. (author)
Sinibaldi, Alberto; Descrovi, Emiliano; Giorgis, Fabrizio; Dominici, Lorenzo; Ballarini, Mirko; Mandracci, Pietro; Danz, Norbert; Michelotti, Francesco
2012-10-01
We exploit the properties of surface electromagnetic waves propagating at the surface of finite one dimensional photonic crystals to improve the performance of optical biosensors with respect to the standard surface plasmon resonance approach. We demonstrate that the hydrogenated amorphous silicon nitride technology is a versatile platform for fabricating one dimensional photonic crystals with any desirable design and operating in a wide wavelength range, from the visible to the near infrared. We prepared sensors based on photonic crystals sustaining either guided modes or surface electromagnetic waves, also known as Bloch surface waves. We carried out for the first time a direct experimental comparison of their sensitivity and figure of merit with surface plasmon polaritons on metal layers, by making use of a commercial surface plasmon resonance instrument that was slightly adapted for the experiments. Our measurements demonstrate that the Bloch surface waves on silicon nitride photonic crystals outperform surface plasmon polaritons by a factor 1.3 in terms of figure of merit.
Numerical simulation of electromagnetic wave propagation using time domain meshless method
International Nuclear Information System (INIS)
Ikuno, Soichiro; Fujita, Yoshihisa; Itoh, Taku; Nakata, Susumu; Nakamura, Hiroaki; Kamitani, Atsushi
2012-01-01
The electromagnetic wave propagation in various shaped wave guide is simulated by using meshless time domain method (MTDM). Generally, Finite Differential Time Domain (FDTD) method is applied for electromagnetic wave propagation simulation. However, the numerical domain should be divided into rectangle meshes if FDTD method is applied for the simulation. On the other hand, the node disposition of MTDM can easily describe the structure of arbitrary shaped wave guide. This is the large advantage of the meshless time domain method. The results of computations show that the damping rate is stably calculated in case with R < 0.03, where R denotes a support radius of the weight function for the shape function. And the results indicate that the support radius R of the weight functions should be selected small, and monomials must be used for calculating the shape functions. (author)
Huba, J. D.; Rowland, H. L.
1993-01-01
The propagation of electromagnetic waves parallel to the magnetic field in the nightside Venus ionosphere is presented in a theoretical and numerical analysis. The model assumes a source of electromagnetic radiation in the Venus atmosphere, such as that produced by lightning. Specifically addressed is wave propagation in the altitude range z = 130-160 km at the four frequencies detectable by the Pioneer Venus Orbiter Electric Field Detector: 100 Hz, 730 Hz, 5.4 kHz, and 30 kHz. Parameterizations of the wave intensities, peak electron density, and Poynting flux as a function of magnetic field are presented. The waves are found to propagate most easily in conditions of low electron density and high magnetic field. The results of the model are consistent with observational data.
International Nuclear Information System (INIS)
Kozyra, J.U.; Cravens, T.E.; Nagy, A.F.; Fontheim, E.G.; Ong, R.S.B.
1984-01-01
An expression for the linear electromagnetic ion cyclotron convective growth rate has been derived, considering multiple ions in the energetic anisotropic component of the plasma (which provides the free energy for the instability) as well as in the cold component of the plasma. This represents a modification of recent treatments investigating electromagnetic ion cyclotron growth rates which have considered only hydrogen ions in the energetic component. Four major effects on the growth and propagation characteristics result from inclusion of heavy ions in the energetic component. Some wave growth occurs at low frequencies below the corresponding marginally unstable wave mode for each heavy ion. Enhanced quasi-monochronomatic peaks in the convective growth rate appear just below the O + and He + gyrofrequency and can be quite pronounced for certain plasma conditions. Stop bands, decreased group velocity and other effects normally attributed to cold heavy ions can be produced or enhanced by heavy ions in the energetic plasma component. Partial or complete suppression of wave growth at frequencies above the marginally unstable wave mode for a particular energetic heavy ion can greatly alter the growth rates that would occur in the absence of this energetic heavy ion. The expression for the linear electromagnetic ion cyclotron convective growth rate along with appropriate plasma parameters was used to investigate the nature of linear wave growth in the plasmapause region. The frequencies of peaks in the convective growth rate given by this model compare favorably with wave measurements in this region. It is conceivable that through wave-particle interactions, electromagnetic ion cyclotron waves could supply the energy source for various plasmapause region phenomena such as the O + torus, the plasma cloak and stable auroral red arcs
Bulakhov, M. G.; Buyanov, Yu. I.; Yakubov, V. P.
1996-10-01
It has been shown that a full vector measurement of the total field allows one to uniquely distinguish the incident and reflected waves at each observation point without the use of a spatial difference based on an analysis of the polarization structure of the interference pattern which arises during reflection of electromagnetic waves from an intermedia boundary. We have investigated the stability of these procedures with respect to measurement noise by means of numerical modeling.
Excitation of the Uller-Zenneck electromagnetic surface waves in the prism-coupled configuration
Rasheed, Mehran; Faryad, Muhammad
2017-08-01
A configuration to excite the Uller-Zenneck surface electromagnetic waves at the planar interfaces of homogeneous and isotropic dielectric materials is proposed and theoretically analyzed. The Uller-Zenneck waves are surface waves that can exist at the planar interface of two dissimilar dielectric materials of which at least one is a lossy dielectric material. In this paper, a slab of a lossy dielectric material was taken with lossless dielectric materials on both sides. A canonical boundary-value problem was set up and solved to find the possible Uller-Zenneck waves and waveguide modes. The Uller-Zenneck waves guided by the slab of the lossy dielectric material were found to be either symmetric or antisymmetric and transmuted into waveguide modes when the thickness of that slab was increased. A prism-coupled configuration was then successfully devised to excite the Uller-Zenneck waves. The results showed that the Uller-Zenneck waves are excited at the same angle of incidence for any thickness of the slab of the lossy dielectric material, whereas the waveguide modes can be excited when the slab is sufficiently thick. The excitation of Uller-Zenneck waves at the planar interfaces with homogeneous and all-dielectric materials can usher in new avenues for the applications for electromagnetic surface waves.
International Nuclear Information System (INIS)
Shiozawa, Toshiyuki
2010-01-01
For the purpose of providing for a theoretical background for the study of electromagnetic fields generated by precursory effects of earthquakes, the problem of transmission and total reflection at the earth-atmosphere interface is investigated in detail for a subhertz plane electromagnetic wave incident from the earth's crust. The term ''subhertz'' means 'below 1 Hz'. First, for the special case of normal incidence, the overall power transmission coefficient at the earth-atmosphere interface is found to take a maximum value at a definite frequency f 0 which is inversely proportional to the square of the depth of a virtual hypocenter. A typical value of f 0 falls around 0.01 Hz. For oblique incidence as well, this feature of the overall power transmission coefficient is retained except in the vicinity of the critical angle of incidence for the H-wave. At the critical angle of incidence, the power flow carried by a surface wave along the interface becomes anomalously large for the H-wave. However, over a wide range of angles of incidence greater than the critical angle, the power flow carried by the E-wave exceeds that carried by the H-wave by orders of magnitude. Finally, the energy conservation relations for the incident, reflected, and transmitted waves at the earth-atmosphere interface are discussed. For an incident wave coming from the earth's crust, the interactive power between the incident and reflected waves plays a crucial role for the conservation of energy at the interface.
The millimeter-wave spectrum of highly vibrationally excited SiO
International Nuclear Information System (INIS)
Mollaaghababa, R.; Gottlieb, C.A.; Vrtilek, J.M.; Thaddeus, P.
1991-01-01
The millimeter-wave rotational spectra of SiO in high vibrational states (v = 0-40) in its electronic ground state were measured between 228 and 347 GHz in a laboratory discharge through SiH4 and CO. On ascending the vibrational ladder, populations decline precipitously for the first few levels, with a vibrational temperature of about 1000 K; at v of roughly 3, however, they markedly flatten out, and from there to v of roughly 40 the temperature is of the order of 10,000 K. With the Dunham coefficients determined here, the rotational spectrum of highly vibrationally excited SiO can now be calculated into the far-infrared to accuracies required for radioastronomy. Possible astronomical sources of highly vibrationally excited SiO are certain stellar atmospheres, ultracompact H II regions, very young supernova ejecta, and dense interstellar shocks. 16 refs
Directory of Open Access Journals (Sweden)
Vojkan M. Radonjić
2011-01-01
Full Text Available Quality transmission of digital signals from a transmitting radio-relay device to a receiving one depends on the impact of environmental effects on the propagation of electromagnetic waves. In this paper some of the most important effects are explained and modeled, especially those characteristic for the frequency range within which the GRC 408E operates. The modeling resulted in the conclusions about the quality of transmission of digital signals in the GRC 408E radio-relay equipment. Propagation of electromagnetic waves A radio-relay link is achieved by direct electromagnetic waves, provided there is a line of sight between the transmitting and receiving antenna of a radio-relay device. Electromagnetic waves on the road are exposed to various environmental influences causing phenomena such as bending, reflection, refraction, absorption and multiple propagation. Due to these environmental effects, the quality of information transmission is not satisfactory and a radio-relay link is not reliable. The approach to the analysis of the quality of links in digital radiorelay devices is different from the one in analog radio-relay devices. Therefore, the quality is seen through errors in the received bit ( BER , the propagation conditions are taken into account, a reservation for the fading is determined by other means, etc.. Phenomena which accompany the propagation of electromagnetic waves in digital radio-relay links The propagation of direct EM waves is followed by the following phenomena: - attenuation due to propagation, - diffraction (changing table, - refraction (refraction, - reflection (refusing, - absorption (absorption and - multiple wave propagation. Each of these has a negative effect on the quality of the received signal at the receiving antenna of the radio-relay device. Attenuation due to propagation of electromagnetic waves The main parameter for evaluating the quality of radio-relay links is the level of the field at the reception
Electromagnetic effects on the self-modulation of nonlinear lower hybrid waves
International Nuclear Information System (INIS)
Hsu, P.; Kuehl, H.H.
1983-01-01
Electromagnetic effects on the self-modulation of nonlinear lower hybrid waves in an inhomogeneous plasma are studied for both broad and narrow spectrum excitations. For broad spectrum excitation, the complex modified Korteweg--de Vries equation is modified by two additional terms due to the electromagnetic correction and inhomogeneity. Numerical solutions of this equation for typical tokamak parameters show that these terms suppress soliton formation. For narrow spectrum excitation, the electromagnetic correction produces an additional dispersive term in the differential equation governing the wave envelope. This term opposes thermal dispersion, resulting in significant self-modulation. Numerical solutions show constriction and splitting of the envelope as well as spreading of the Fourier spectrum
Measurement of the environmental broadband electromagnetic waves in a mid-size European city.
Fernández-García, R; Gil, I
2017-10-01
In this paper, the level of exposure to broadband radiofrequency electromagnetic field in a mid-size European city was evaluated in accordance with the International Commission on Non-ionizing Radiation Protection guidelines from 1998. With the aim to analyse all the potential electromagnetic waves present in the city up to 18GHz, a total of 271 locations distributed along Terrassa (Spain) have been measured. To show the results in an easy-to-interpret way by the citizen, the results have been represented in a set of raster maps. The measurement results obtained showed that the electromagnetic wave measured in all broadband frequency range along the city is much lower than the safety level according to the international regulations for both public and occupational sectors. Copyright © 2017 Elsevier Inc. All rights reserved.
Success of electromagnetic shock wave lithotripter as monotherapy ...
African Journals Online (AJOL)
K.S. Meitei
Objectives: To evaluate the success of shock wave lithotripsy (SWL) as monotherapy for solitary .... history of previous renal surgery on the affected side were excluded .... energy. Twelve (63.2%) of the steinstrasse cases were managed con-.
Assessment methodology of counter-personnel high power electromagnetic millimeter wave effects
Valente, F.; Horst, M.J. van der; Paulissen, J.J.M.; Zwamborn, A.P.M.; Toet, A.
2013-01-01
The group of NLW that arguably offers the largest amount of useful applications are based on high power electromagnetic millimetre wave technology. This group is often referred to as ‘Active Denial Systems’ (ADS), since they are primarily aimed at deterring and dispersing people out of an area. The
Magnetization of a warm plasma by the nonstationary ponderomotive force of an electromagnetic wave
International Nuclear Information System (INIS)
Shukla, Nitin; Shukla, P. K.; Stenflo, L.
2009-01-01
It is shown that magnetic fields can be generated in a warm plasma by the nonstationary ponderomotive force of a large-amplitude electromagnetic wave. In the present Brief Report, we derive simple and explicit results that can be useful for understanding the origin of the magnetic fields that are produced in intense laser-plasma interaction experiments.
Transversality of Electromagnetic Waves in the Calculus-Based Introductory Physics Course
Burko, Lior M.
2008-01-01
Introductory calculus-based physics textbooks state that electromagnetic waves are transverse and list many of their properties, but most such textbooks do not bring forth arguments why this is so. Both physical and theoretical arguments are at a level appropriate for students of courses based on such books, and could be readily used by…
FDTD-analyse of electromagnetic wave propagation through photonic band gap structure
International Nuclear Information System (INIS)
Brendel', M.O.; Danilov, V.V.; Makarov, D.G.; Nechiporuk, O.Yu.
2007-01-01
FDTD-method for numerical solution of Maxwell's equation has used for investigation of electromagnetic wave transmission through the periodically inhomogeneous planar waveguide. The spectral dependence for transmission factor has obtained. This result compared with the previous one, obtained with approximate analytical calculations
NUMERICAL STUDY OF ELECTROMAGNETIC WAVES GENERATED BY A PROTOTYPE DIELECTRIC LOGGING TOOL
To understand the electromagnetic waves generated by a prototype dielectric logging tool, a numerical study was conducted using both the finite-difference, time-domain method and a frequency- wavenumber method. When the propagation velocity in the borehole was greater than th...
Resonant generation of electromagnetic surface wave by inhomogeneous relativistic electron stream
Energy Technology Data Exchange (ETDEWEB)
Cadez, V.M.; Vukovic, S. (Belgrade Univ. (Yugoslavia). Inst. za Fiziku); Frolov, V.V.; Kyrie, A.Y. (AN SSSR, Moscow. Fizicheskij Inst.)
1981-12-01
Generation of electromagnetic surface waves by relativistic inhomogeneous particle flows is investigated for plane and cylindrical geometries. The basic excitation mechanisms are shown to be the induced anomalous Doppler effect and the hydrodynamic Cerenkov effect. The relevant maximal growth rates may differ significantly from those derived for monoenergetic beams.
Resonant generation of electromagnetic surface wave by inhomogeneous relativistic electron stream
International Nuclear Information System (INIS)
Cadez, V.M.; Vukovic, S.; Frolov, V.V.; Kyrie, A.Y.
1981-01-01
Generation of electromagnetic surface waves by relativistic inhomogeneous particle flows is investigated for plane and cylindrical geometries. The basic excitation mechanisms are shown to be the induced anomalous Doppler effect and the hydrodynamic Cerenkov effect. The relevant maximal growth rates may differ significantly from those derived for monoenergetic beams. (author)
International Nuclear Information System (INIS)
Brodin, G.; Lundberg, J.
1990-01-01
To study the stability of a finite amplitude circularly polarized electromagnetic wave in a plasma with pressure anisotropy we make use of a generalized version of the Chew-Goldberger-Low equations. The dispersion relation is derived. Special attention is focused on the MHD-limit. (orig.)
Detection of Metallic and Electronic Radar Targets by Acoustic Modulation of Electromagnetic Waves
2017-07-01
by Acoustic Modulation of Electromagnetic Waves 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Gregory J... Program 13 List of Symbols, Abbreviations, and Acronyms 18 Distribution List 19 Approved for public release; distribution is...4 Fig. 4 Flowchart of wireless experiment to receive acoustically modulated radar waveforms
Electromagnetic-wave absorption by inhomogeneous, collisional plasmas
International Nuclear Information System (INIS)
Gregoire, D.J.; Santoru, J.; Schumacher, R.W.
1990-01-01
Unmagnetized, collisional plasmas can be used as broadband EM-wave absorbers or refractors. In the absorption process, plasma electrons are first accelerated by the EM-wave fields and then collide with background-gas molecules, thereby transferring energy from the EM waves to the gas. A plasma absorber has several advantages compared to conventional materials. A plasma can be turned on and off very rapidly, thereby switching between absorbing and transparent conditions. Calculations indicate that plasma absorbers can also be tailored to provide broadband absorption (>40 dB) over multiple octaves. The authors have developed a one-dimensional model and a computer code to calculate the net power reflected from a plasma-enclosed EM-wave-reflecting target. They included three contributions to the reflected EM-wave power: reflections from the vacuum-plasma interface; reflections from the bulk plasma volume; and reflection of the attenuated EM wave that is transmitted through the plasma and reflected by the target
Electromagnetic ion cyclotron waves observed near the oxygen cyclotron frequency by ISEE 1 and 2
International Nuclear Information System (INIS)
Fraser, B.J.; Samson, J.C.; Hu, Y.D.; McPherron, R.L.; Russell, C.T.
1992-01-01
Pc 2 electromagnetic ion cyclotron waves at 0.1 waves at 0.1 Hz, near the oxygen cyclotron frequency, have been observed by ISEE 1 and 2 between L = 7.6 and 5.8 on an inbound near-equatorial pass in the dusk sector. The waves occurred in a thick plasmapause of width ∼ 1.5 R E and penetrated ∼1 R E into the plasmasphere. Wave onset was accompanied by significant increases in the thermal (0-100 eV) He + and the warm (0.1-16 keV/e) O + and He + heavy ion populations. The most intense waves (8 nT) were observed in the outer plasmasphere where convection drift velocities (E x B)/B 2 were largest and the Alfven velocity was a minimum. Wave polarization is predominantly left-handed with propagation almost parallel to the ambient magnetic field, and the spectral slot and polarization reversal predicted by cold plasma propagation theory are identified in the wave data. Poynting fluxes calculated during the first 15 min of the event show wave energy propagation directions both parallel and antiparallel to the field. Computations of the experimental wave spectra during the passage through the plasmapause show that the spectral slots relate to local plasma parameters, possibly suggesting an ion cyclotron wave growth source near the spacecraft. A regular wave packet structure seen over the first 30 min of the event may be attributed to the modulation of this energy source by the Pc 5 waves seen at the same time. Overall, the results are considered an example of an electromagnetic ion cyclotron wave-particle interaction occurring during the outer plasmasphere refilling process at the time of the substorm recovery phase
Modal Ring Method for the Scattering of Electromagnetic Waves
Baumeister, Kenneth J.; Kreider, Kevin L.
1993-01-01
The modal ring method for electromagnetic scattering from perfectly electric conducting (PEC) symmetrical bodies is presented. The scattering body is represented by a line of finite elements (triangular) on its outer surface. The infinite computational region surrounding the body is represented analytically by an eigenfunction expansion. The modal ring method effectively reduces the two dimensional scattering problem to a one-dimensional problem similar to the method of moments. The modal element method is capable of handling very high frequency scattering because it has a highly banded solution matrix.
Collective scattering of electromagnetic waves from a relativistic magnetized plasma
International Nuclear Information System (INIS)
Lu Quankang
1998-01-01
Recently, laser and microwave scattering has become one of the important diagnostic means for plasma. Laser and microwave correlative scattering spectrum is determined by particle-density fluctuations in a weak turbulent plasma. In a relativistic plasma, on the basis of complete electromagnetic-interaction between particles, a general expression for particle density fluctuations and spectrums of laser and microwave scattering from a magnetized plasma are derived. The laser and microwave scattering spectrums provide informations on electron density and temperature, ion temperature, resonance and nonresonance effects. (author)
Ions cross-B collisional diffusion and electromagnetic wave scattering
International Nuclear Information System (INIS)
Tomchuk, B.P.; Gresillon, D.
2000-01-01
The calculation is presented of the averaged quadratic displacement of a collisional charged particle in a magnetic field. This calculation is used to obtain the statistical presentation of the electromagnetic field scattered by these particles. These results extend the previous calculations that were restricted to non-magnetized particles (Ornstein equation, Einstein diffusion, etc.). In addition this calculation foresees effects that are absent of the Ornstein equation: a modulation of the averaged quadratic displacement function at the cyclotron frequency and a maximum of the Cross-B diffusion coefficient when the cyclotron frequency is equal to the collision frequency (Bohm diffusion)
Spectrum of the seismic-electromagnetic and acoustic waves caused by seismic and volcano activity
Directory of Open Access Journals (Sweden)
S. Koshevaya
2005-01-01
Full Text Available Modeling of the spectrum of the seismo-electromagnetic and acoustic waves, caused by seismic and volcanic activity, has been done. This spectrum includes the Electromagnetic Emission (EME, due to fracturing piezoelectrics in rocks and the Acoustic Emission (AE, caused by the excitation and the nonlinear passage of acoustic waves through the Earth's crust, the atmosphere, and the ionosphere. The investigated mechanism of the EME uses the model of fracturing and the crack motion. For its analysis, we consider a piezoelectric crystal under mechanical stresses, which cause the uniform crack motion, and, consequently, in the vicinity of the moving crack also cause non-stationary polarization currents. A possible spectrum of EME has been estimated. The underground fractures produce Very Low (VLF and Extremely Low Frequency (ELF acoustic waves, while the acoustic waves at higher frequencies present high losses and, on the Earth's surface, they are quite small and are not registered. The VLF acoustic wave is subject to nonlinearity under passage through the lithosphere that leads to the generation of higher harmonics and also frequency down-conversion, namely, increasing the ELF acoustic component on the Earth's surface. In turn, a nonlinear propagation of ELF acoustic wave in the atmosphere and the ionosphere leads to emerging the ultra low frequency (ULF acousto-gravity waves in the ionosphere and possible local excitation of plasma waves.
Ren, Hengxin; Huang, Qinghua; Chen, Xiaofei
2018-03-01
We conduct numerical simulations and theoretical analyses to quantitatively study the amplitude decay characteristic of the evanescent electromagnetic (EM) waves, which has been neglected in previous studies on the seismoelectric conversion occurring at a porous-porous interface. Time slice snapshots of seismic and EM wave-fields generated by a vertical single force point source in a two-layer porous model show that evanescent EM waves can be induced at a porous-porous interface. The seismic and EM wave-fields computed for a receiver array located in a vertical line nearby the interface are investigated in detail. In addition to the direct and interface-response radiation EM waves, we identify three groups of coseismic EM fields and evanescent EM waves associated with the direct P, refracted SV-P and direct SV waves, respectively. Thereafter, we derive the mathematical expression of the amplitude decay factor of the evanescent EM waves. This mathematical expression is further validated by our numerical simulations. It turns out the amplitude decay of the evanescent EM waves generated by seismoelectric conversion is greatly dependent on the horizontal wavenumber of seismic waves. It is also found the evanescent EM waves have a higher detectability at a lower frequency range. This work provides a better understanding on the EM wave-fields generated by seismoelectric conversion, which probably will help improve the interpretation of the seismoelectric coupling phenomena associated with natural earthquakes or possibly will inspire some new ideas on the application of the seismoelectric coupling effect.
Global Characteristics of Electromagnetic Ion Cyclotron Waves Deduced From Swarm Satellites
Kim, Hyangpyo; Hwang, Junga; Park, Jaeheung; Bortnik, Jacob; Lee, Jaejin
2018-02-01
It is well known that electromagnetic ion cyclotron (EMIC) waves play an important role in controlling particle dynamics inside the Earth's magnetosphere, especially in the outer radiation belt. In order to understand the results of wave-particle interactions due to EMIC waves, it is important to know how the waves are distributed and what features they have. In this paper, we present some statistical analyses on the spatial distribution of EMIC waves in the low Earth orbit by using Swarm satellites from December 2013 to June 2017 ( 3.5 years) as a function of magnetic local time, magnetic latitude, and magnetic longitude. We also study the wave characteristics such as ellipticity, wave normal angle, peak frequency, and wave power using our automatic wave detection algorithm based on the method of Bortnik et al. (2007, https://doi.org/10.1029/2006JA011900). We also investigate the geomagnetic control of the EMIC waves by comparing with geomagnetic activity represented by Kp and Dst indices. We find that EMIC waves are detected with a peak occurrence rate at midlatitude including subauroral region, dawn sector (3-7 magnetic local time), and linear polarization dominated with an oblique propagating direction to the background magnetic field. In addition, our result shows that the waves have some relation with geomagnetic activity; that is, they occur preferably during the geomagnetic storm's late recovery phase at low Earth orbit.
Energy Technology Data Exchange (ETDEWEB)
Li, Bin Peng [Research Center of Carbon Fiber, Key Laboratory for Liquid–Solid Structural Evolution and Processing of Materials of Ministry of Education, Shandong University, Jinan 250061 (China); Tianjin Binhai New Area Finance Bureau, Tianjin 300450 (China); Wang, Cheng Guo, E-mail: sduwangchg@gmail.com [Research Center of Carbon Fiber, Key Laboratory for Liquid–Solid Structural Evolution and Processing of Materials of Ministry of Education, Shandong University, Jinan 250061 (China); Wang, Wen [Norinco Group China North Material Science and Engineering Technology Group Corporation, Jinan 250031 (China); Yu, Mei Jie; Gao, Rui; Chen, Yang; Xiang Wang, Yan [Research Center of Carbon Fiber, Key Laboratory for Liquid–Solid Structural Evolution and Processing of Materials of Ministry of Education, Shandong University, Jinan 250061 (China)
2014-09-01
Composites with micro-sized magnetic particles dispersed in amorphous carbon were fabricated conveniently and economically by carbonizing polyacrylonitrile (PAN) fibers mixed with micro-sized iron particles under different temperatures. The composites were characterized by X-ray diffraction (XRD) and scanning electric microscope (SEM). The electromagnetic (EM) properties were measured by a vector network analyzer in the frequency range of 2–18 GHz based on which analog computations of EM wave absorption properties were carried out. The influences of temperature on phase composition and EM wave absorption properties were also investigated, indicating that the composites had good electromagnetic absorption properties with both electrical loss and magnetic loss. Effective reflection loss (RL<−10 dB) was observed in a large frequency range of 7.5–18 GHz with the absorber thickness of 2.0–3.0 mm for the paraffin samples with composite powders heated up to 750 °C and the minimum absorption peak around −40 dB appeared at approximately 10 GHz with matching thickness of 2.0 mm for the paraffin sample with composite powders heated up to 800 °C. - Highlights: • High-performance electromagnetic wave absorption materials were fabricated conveniently and economically. • The materials are composites with micro-sized magnetic particles dispersed in porous amorphous carbon. • The influences of temperature on phase composition and electromagnetic wave absorption properties were investigated. • The composites heated up to 750 °C and 800 °C had good electromagnetic wave absorption property.
Modeling the propagation of electromagnetic waves over the surface of the human body
Vendik, I. B.; Vendik, O. G.; Kirillov, V. V.; Pleskachev, V. V.; Tural'chuk, P. A.
2016-12-01
The results of modeling and an experimental study of electromagnetic (EM) waves in microwave range propagating along the surface of the human body have been presented. The parameters of wave propagation, such as the attenuation and phase velocity, have also been investigated. The calculation of the propagation of EM waves by the numerical method FDTD (finite difference time domain), as well as the use of the analytical model of the propagation of the EM wave along flat and curved surfaces has been fulfilled. An experimental study on a human body has been conducted. It has been shown that creeping waves are slow and exhibit a noticeable dispersion, while the surface waves are dispersionless and propagate at the speed of light in free space. A comparison of the results of numerical simulation, analytical calculation, and experimental investigations at a frequency of 2.55 GHz has been carried out.
The theory of electromagnetic wave scattering by density fluctuations in nonequilibrium plasma
International Nuclear Information System (INIS)
Pavlenko, V.N.; Panchenko, V.G.
1993-01-01
Scattering of electromagnetic waves by density fluctuations in a magnetized plasma in the presence of the external pump field is investigated. The spectral density of electron density fluctuations is calculated. The pump wave is supposed to decay into a lower hybrid wave and low frequency oscillations (ion-acoustic wave, modified convective cell and ion-cyclotron wave with ion-temperature anisotropy). When the pump wave amplitude tends to the threshold strength of the electric field, the scattering cross section increases anomalously, i.e. there is the critical opalescence. The differential scattering cross section dependence on the pump amplitude and ion temperature anisotropy is obtained in the region above the parametric instability threshold. For characteristic parameters of fusion and space plasmas it is shown that the pump field terms considerably surmount the thermal noise contribution to the scattering cross section
75th Anniversary of `Existence of Electromagnetic-Hydrodynamic Waves'
Russell, Alexander J. B.
2018-05-01
We have recently passed the 75th anniversary of one of the most important results in solar and space physics: Hannes Alfvén's discovery of Alfvén waves and the Alfvén speed. To celebrate the anniversary, this article recounts some major episodes in the history of magnetohydrodynamic (MHD) waves. Following an initially cool reception, Alfvén's ideas were propelled into the spotlight by Fermi's work on cosmic rays, the new mystery of coronal heating, and, as scientific perception of interplanetary space shifted dramatically and the space race started, detection of Alfvén waves in the solar wind. From then on, interest in MHD waves boomed, laying the foundations for modern remote observations of MHD waves in the Sun, coronal seismology, and some of today's leading theories of coronal heating and solar wind acceleration. In 1970, Alfvén received the Nobel Prize for his work in MHD, including these discoveries. The article concludes with some reflection about what the history implies about the way we do science, especially the advantages and pitfalls of idealised mathematical models.
Resonant interactions between cometary ions and low frequency electromagnetic waves
Thorne, Richard M.; Tsurutani, Bruce T.
1987-01-01
The conditions for resonant wave amplification in a plasma with a ring-beam distribution which is intended to model pick-up ions in a cometary environment are investigated. The inclination between the interplanetary field and the solar wind is found to play a crucial role in governing both the resonant frequency and the growth rate of any unstable mode. It is suggested that the low-frequency MHD mode should experience the most rapid amplification for intermediate inclination. In the frame of the solar wind, such waves should propagate along the field in the direction upstream toward the sun with a phase speed lower than the beaming velocity of the pick-up ions. This mechanism may account for the presence of the interior MHD waves noted by satellites over a region surrounding comets Giacobini-Zinner and Halley.
Preparation and electromagnetic wave absorption of RGO/Cu nanocomposite
Zhang, Hui; Tian, Xingyou; Zhang, Xian; Li, Shikuo; Shen, Yuhua; Xie, Anjian
2017-09-01
We use a facile pyrolysis method to prepare reduced graphene oxide and copper nanocomposite (RGO/Cu) based on it. The product shows an outstanding wave absorption properties. The maximum reflection loss is up to-50.7 dB at 3.8 GHz. The reflection loss of-10 dB (90% power absorption) corresponds to a bandwidth of 11.2 GHz (3.4-14.6 GHz range) for the layer thickness of 2-5 mm. Therefore, it is suggested that the RGO/Cu nanocomposite is also a new kind of lightweight and high-performance EM wave absorbing material.
Ultra-low-frequency electromagnetic waves in the Earth's crust and magnetosphere
International Nuclear Information System (INIS)
Guglielmi, A V
2007-01-01
Research on natural intra- and extraterrestrially produced electromagnetic waves with periods ranging from 0.2 to 600 s is reviewed. The way in which the energy of rock movements transforms into the energy of an alternating magnetic field is analyzed. Methods for detecting seismomagnetic signals against a strong background are described. In discussing the physics of ultra-low-frequency waves in the magnetosphere, the 11-year activity modulation of 1-Hz waves and ponderomotive forces affecting plasma distribution are emphasized. (reviews of topical problems)
To the theory of quantum processes in the field of an intense electromagnetic wave
International Nuclear Information System (INIS)
Bajer, V.N.; Katkov, V.M.; Mil'shtejn, A.I.; Strakhovenko, V.M.
1975-01-01
The operator diagram technique, developed earlier for considering phenomena in a homogeneous external field, is applied to processes occurring in a plane electromagnetic wave field. Calculations are carried out on the basis of a specific technique of ''entangling'' of operator expressions. The mass operator of scalar and spinor particles determined by a double integral is found in the field of an elliptically polarized wave of a general type. Imaginary part of the operator presents a new concept of the full probability of a particle emission in a wave field. Polarization effects are analyzed for spinor particles
Weakly nonlinear electromagnetic waves in an electron-ion positron plasma
International Nuclear Information System (INIS)
Rizzato, F.B.; Schneider, R.S.; Dillenburg, D.
1987-01-01
The modulation of a high-frequency electromagnetic wave which is circulary polarized and propagates in a plasma made up of electrons, ions and positrons is investigated. The coefficient of the cubic nonlinear term in the Schroedinger equation may change sign as the relative particle concentrations vary, and consequently a marginal state of modulation instability may exist. To described the system in the neighbourhood of this state an appropriate equation is derived. Particular stationary solutions of this equation are envelope solitary waves, envelope Kinks and envelope hole solitary waves. The dependence of the amplitude of the solutions on the propagation velocity and the particle concentrations is discussed. (author) [pt
DEFF Research Database (Denmark)
Sakai, S.; Ustinov, A. V.; Kohlstedt, H.
1994-01-01
Characteristic velocities of the electromagnetic waves propagating in vertically stacked Josephson transmission are theoretically discussed. An equation for solving n velocities of the waves in an n Josephson-junction stack is derived. The solutions of two- and threefold stacks are especially...... focused on. Furthermore, under the assumption that all parameters of the layers are equal, analytic solutions for a generic N-fold stack are presented. The velocities of the waves in two- and three-junction stacks by Nb-Al-AlOx-Nb systems are experimentally obtained by measuring the cavity resonance...
Bogatskaya, A. V.; Klenov, N. V.; Tereshonok, M. V.; Adjemov, S. S.; Popov, A. M.
2018-05-01
We present an analysis of the possibility of penetrating electromagnetic waves through opaque media using an optical-mechanical analogy. As an example, we consider the plasma sheath surrounding the vehicle as a potential barrier and analyze the overcoming of radiocommunication blackout problem. The idea is to embed a «resonator» between the surface on the vehicle and plasma sheath which is supposed to provide an effective tunneling of the signal to the receiving antenna. We discuss the peculiarities of optical mechanical analogy applicability and analyze the radio frequency wave tunneling regime in detail. The cases of normal and oblique incidence of radiofrequency waves on the vehicle surface are studied.
Yu, Tianbao; Wang, Zhong; Liu, Wenxing; Wang, Tongbiao; Liu, Nianhua; Liao, Qinghua
2016-04-18
We report numerically large and complete photonic and phononic band gaps that simultaneously exist in eight-fold phoxonic quasicrystals (PhXQCs). PhXQCs can possess simultaneous photonic and phononic band gaps over a wide range of geometric parameters. Abundant localized modes can be achieved in defect-free PhXQCs for all photonic and phononic polarizations. These defect-free localized modes exhibit multiform spatial distributions and can confine simultaneously electromagnetic and elastic waves in a large area, thereby providing rich selectivity and enlarging the interaction space of optical and elastic waves. The simulated results based on finite element method show that quasiperiodic structures formed of both solid rods in air and holes in solid materials can simultaneously confine and tailor electromagnetic and elastic waves; these structures showed advantages over the periodic counterparts.
On the effects of geometry on guided electromagnetic waves
Directory of Open Access Journals (Sweden)
Tucker Robin W.
2007-01-01
Full Text Available The method of moving (Cartan coframes is used to analyze the influence of geometry on the behavior of electromagnetic fields in confining guides and the effect of such fields on their ultra-relativistic sources. Such issues are of relevance to a number of topical problems in accelerator science where the need to control the motion of high current-density micro-meter size bunches of relativistic radiating charge remains a technical and theoretical challenge. By dimensionally reducing the exterior equations for the sources and fields on spacetime using symmetries exhibited by the confining guides one achieves a unifying view that offers natural perturbative approaches for dealing with smooth non-uniform and curved guides. The issue of the back-reaction of radiation fields on the sources is approached in terms of a simple charged relativistic fluid model. .
Propagation and scattering of electromagnetic waves by the ionospheric irregularities
International Nuclear Information System (INIS)
Ho, A.Y.; Kuo, S.P.; Lee, M.C.
1993-01-01
The problem of wave propagation and scattering in the ionosphere is particularly important in the areas of communications, remote-sensing and detection. The ionosphere is often perturbed with coherently structured (quasiperiodic) density irregularities. Experimental observations suggest that these irregularities could give rise to significant ionospheric effect on wave propagation such as causing spread-F of the probing HF sounding signals and scintillation of beacon satellite signals. It was show by the latter that scintillation index S 4 ∼ 0.5 and may be as high as 0.8. In this work a quasi-particle theory is developed to study the scintillation phenomenon. A Wigner distribution function for the wave intensity in the (k,r) space is introduced and its governing equation is derived with an effective collision term giving rise to the attenuation and scattering of the wave. This kinetic equation leads to a hierarchy of moment equations in r space. This systems of equations is then truncated to the second moment which is equivalent to assuming a cold quasi-particle distribution In this analysis, the irregularities are modeled as a two dimensional density modulation on an uniform background plasma. The analysis shows that this two dimensional density grating, effectively modulates the intensity of the beacon satellite signals. This spatial modulation of the wave intensity is converted into time modulation due to the drift of the ionospheric irregularities, which then contributes to the scintillation of the beacon satellite signals. Using the proper plasma parameters and equatorial measured data of irregularities, it is shown that the scintillation index defined by S4=( 2 >- 2 )/ 2 where stands for spatial average over an irregularity wavelength is in the range of the experimentally detected values
International Nuclear Information System (INIS)
Rao, N.N.
1998-01-01
A systematic analysis of the stationary propagation of nonlinearly coupled electromagnetic and ion-acoustic waves in an unmagnetized plasma via the ponderomotive force is carried out. For small but finite amplitudes, the governing equations have a Hamiltonian structure, but with a kinetic energy term that is not positive definite. The Hamiltonian is similar to the well-known Hacute enon endash Heiles Hamiltonian of nonlinear dynamics, and is completely integrable in three regimes of the allowed parameter space. The corresponding second invariants of motion are also explicitly obtained. The integrable parameter regimes correspond to supersonic values of the Mach number, which characterizes the propagation speed of the coupled waves. On the other hand, in the sub- as well as near-sonic regimes, the coupled mode equations admit different types of exact analytical solutions, which represent nonlinear localized eigenstates of the electromagnetic field trapped in the density cavity due to the ponderomotive potential. While the density cavity has always a single-dip structure, for larger amplitudes it can support higher-order modes having a larger number of nodes in the electromagnetic field. In particular, we show the existence of a new type of localized electromagnetic wave whose field intensity has a triple-hump structure. For typical parameter values, the triple-hump solitons propagate with larger Mach numbers that are closer to the sonic limit than the single- as well as the double-hump solitons, but carry a lesser amount of the electromagnetic field energy. A comparison between the different types of solutions is carried out. The possibility of the existence of trapped electromagnetic modes having a larger number of humps is also discussed. copyright 1998 American Institute of Physics
Electromagnetic backscattering from freak waves in (1 + 1)-dimensional deep-water
International Nuclear Information System (INIS)
Tao, Xie; Tao, Shen; Wei, Chen; Hai-Lan, Kuang; Perrie, William
2010-01-01
To study the electromagnetic (EM) backscatter characteristics of freak waves at moderate incidence angles, we establish an EM backscattering model for freak waves in (1 + 1)-dimensional deep water. The nonlinear interaction between freak waves and Bragg short waves is considered to be the basic hydrodynamic spectra modulation mechanism in the model. Numerical results suggest that the EM backscattering intensities of freak waves are less than those from the background sea surface at moderate incidence angles. The normalised radar cross sections (NRCSs) from freak waves are highly polarisation dependent, even at low incidence angles, which is different from the situation for normal sea waves; moreover, the NRCS of freak waves is more polarisation dependent than the background sea surface. NRCS discrepancies between freak waves and the background sea surface with using horizontal transmitting horizomtal (HH) polarisation are larger than those using vertical transmitting vertical (VV) polarisation, at moderate incident angles. NRCS discrepancies between freak waves and background sea surface decreases with the increase of incidence angle, in both HH and VV polarisation radars. As an application, in the synthetic-aperture radar (SAR) imaging of freak waves, we suggest that freak waves should have extremely low backscatter NRCSs for the freak wave facet with the strongest slope. Compared with the background sea surface, the freak waves should be darker in HH polarisation echo images than in VV echo images, in SAR images. Freak waves can be more easily detected from the background sea surface in HH polarisation images than in VV polarisation images. The possibility of detection of freak waves at low incidence angles is much higher than at high incidence angles. (classical areas of phenomenology)
Energy Technology Data Exchange (ETDEWEB)
Aivazyan, Yu M; Mergelyan, O S; Poulatov, M P
1974-01-01
Aproblem for the diffraction of a plane electromagnetic wave on a dielectric plate between two other dielectrics is solved. The dielectric constant of the plate depends periodically on three coordinates. From this solution it is possible to obtain the equations for fields and the angular distribution of diffracted waves for the particular cases of a crystal plate and a dielectric surface fluted in all directions. If the expansion is made in the variable of the electron density in crystals, the results will correspond to the problem for the X-ray diffraction on a crystal lattice, the values of the coefficient ..cap alpha -->..sub(tau) being determined by the lattice parameters.
The role of ro-vibrational coupling in the revival dynamics of diatomic molecular wave packets
International Nuclear Information System (INIS)
Banerji, J; Ghosh, Suranjana
2006-01-01
We study the revival and fractional revivals of a diatomic molecular wave packet of circular states whose weighing coefficients are peaked about a vibrational quantum number ν-bar and a rotational quantum number j-bar. Furthermore, we show that the interplay between the rotational and vibrational motion is determined by a parameter γ =√D/C, where D is the dissociation energy and C is inversely proportional to the reduced mass of the two nuclei. Using I 2 and H 2 as examples, we show, both analytically and visually (through animations), that for γ>>ν-bar, j-bar, the rotational and vibrational time scales are so far apart that the ro-vibrational motion gets decoupled and the revival dynamics depends essentially on one time scale. For γ∼ν-bar, j-bar, on the other hand, the evolution of the wave packet depends crucially on both the rotational and vibrational time scales of revival. In the latter case, an interesting rotational-vibrational fractional revival is predicted and explained
Novel Aspects of Evolution of the Stokes Parameters for an Electromagnetic Wave in Anisotropic Media
Botet, R.; Kuratsuji, H.; Seto, R.
2006-08-01
Polarization of a plane electromagnetic wave travelling through a medium is studied in the slowly-varying field envelope approximation. It is shown that the problem is identical to the 4-momentum evolution of a negatively-charged massless relativistic particle in an electromagnetic field. The approach is exemplified by the resonant oscillations of circular polarization in a medium embedded in a static magnetic field and a modulated electric field. The effect of dissipation in the medium is discussed. It is shown that the Rabi oscillations are stable below a threshold depending on the absorption coefficient. Above it, oscillations disappear.
Surface solitons of four-wave mixing in an electromagnetically induced lattice
International Nuclear Information System (INIS)
Zhang, Yanpeng; Yuan, Chenzhi; Zhang, Yiqi; Zheng, Huaibin; Chen, Haixia; Li, Changbiao; Wang, Zhiguo; Xiao, Min
2013-01-01
By creating lattice states with two-dimensional spatial periodic atomic coherence, we report an experimental demonstration of generating two-dimensional surface solitons of a four-wave mixing signal in an electromagnetically induced lattice composed of two electromagnetically induced gratings with different orientations in an atomic medium, each of which can support a one-dimensional surface soliton. The surface solitons can be well controlled by different experimental parameters, such as probe frequency, pump power, and beam incident angles, and can be affected by coherent induced defect states. (letter)
Adrian, M. L.; Wendel, D. E.
2011-01-01
We investigate observations of intense bursts of electromagnetic wave energy in association with the thin current layers of turbulent magnetosheath reconnection. These observed emissions form two distinct types: (i) broadband emissions that extend continuously to lOs of Hertz; and (ii) structured bursts of emitted energy that occur above 80-Hz, often displaying features reminiscent of absorption bands and are observed at local minima in the magnetic field. We present detailed analyses of these intense bursts of electromagnetic energy and quantify their proximity to X- and O-nulls, as well as their correlation to the amount of magnetic energy converted by the process of magnetic reconnection.
The SEM description of interaction of a transient electromagnetic wave with an object
Pearson, L. W.; Wilton, D. R.
1980-01-01
The singularity expansion method (SEM), proposed as a means for determining and representing the transient surface current density induced on a scatterer by a transient electromagnetic wave is described. The resulting mathematical description of the transient surface current on the object is discussed. The data required to represent the electromagnetic scattering properties of a given object are examined. Experimental methods which were developed for the determination of the SEM description are discussed. The feasibility of characterizing the surface current induced on aircraft flying in proximity to a lightning stroke by way of SEM is examined.
Nonlinear interactions of electromagnetic waves with the auroral ionosphere
Wong, Alfred Y.
1999-09-01
The ionosphere provides us with an opportunity to perform plasma experiments in an environment with long confinement times, very large-scale lengths, and no confining walls. The auroral ionosphere with its nearly vertical magnetic field geometry is uniquely endowed with large amount of free energy from electron and ion precipitation along the magnetic field and mega-ampere current across the magnetic field. To take advantage of this giant outdoor laboratory, two facilities HAARP and HIPAS, with frequencies ranging from the radio to optical bands, are now available for active probing of and interaction with this interesting region. The ponderomotive pressures from the self-consistent wave fields have produced significant local perturbations of density and particle distributions at heights where the incident EM frequency matches a plasma resonance. This paper will review theory and experiments covering the nonlinear phenomena of parametric decay instability to wave collapse processes. At HF frequencies plasma lenses can be created by preconditioning pulses to focus what is a normally divergent beam into a high-intensity spot to further enhance nonlinear phenomena. At optical wavelengths a large rotating liquid metal mirror is used to focus laser pulses up to a given height. Such laser pulses are tuned to the same wavelengths of selected atomic and molecular resonances, with resulting large scattering cross sections. Ongoing experiments on dual-site experiments and excitation of ELF waves will be presented. The connection of such basic studies to environmental applications will be discussed. Such applications include the global communication using ELF waves, the ozone depletion and remediation and the control of atmospheric CO2 through the use of ion cyclotron resonant heating.
Some problems in generalized electromagnetic thermoelasticity and wave propagation
International Nuclear Information System (INIS)
Mohamed, S.E.S.
2012-01-01
The first chapter contains a review of the classical theory of elasticity, the theory of thermodynamics, the theory of uncoupled thermoelasticity, the coupled theory of thermoelasticity, the generalized theory of thermoelasticity with one relaxation time, electromagneto thermoelasticity and an introduction to wave propagation in elastic media. Chapter two is devoted to the study of wave propagation for a problem of an infinitely long solid conducting circular cylinder whose lateral surface is traction free and subjected to a known surrounding temperatures in the presence of a uniform magnetic field in the direction of the axis of the cylinder. Laplace transform techniques are used to derive the solution in the Laplace transform domain. The inversion process is carried out using asymptotic expansions valid for short tines. Numerical results are computed for the temperature, displacement, stress,induced magnetic field and induced electric field distributions. The chapter contains also a study of the wave propagation in the elastic medium. In chapter three, we consider the two-dimensional problem of an infinitely long conducting solid cylinder. The lateral surface of the cylinder is taken to be traction free and is subjected to a known temperature distribution independent of z in the presence of a uniform magnetic field in the direction of the axis of the cylinder. Laplace transform techniques are used. The inversion process is carried out using a numerical method based on Fourier series expansions. Numerical results are computed and represented graphically. The chapter contains also a study of the wave propagation in the elastic medium. In chapter four, we consider a two-dimensional problem for an infinity long cylinder. The lateral surface of the cylinder is taken to be traction free and is subjected to a known temperature distribution independent of φ in the presence of a uniform electric field in the direction of the binomial of the cylinder axis. Laplace and
International Nuclear Information System (INIS)
Benova, E.; Ghanashev, I.; Zhelyazkov, I.
1992-01-01
The modelling of isotropic plasma columns sustained by travelling electromagnetic waves in the dipolar mode (angular dependence exp imφ, m=±1) shows that the m=±1 modes have identical dispersion characteristics. In the presence of an external static magnetic field, however, the modes behave rather differently. This observation arose in studying the axial structures of magnetized plasma columns surrounded by vacuum and produced by travelling electromagnetic waves in the dipolar modes. We examine the propagation of electromagnetic waves along a homogeneous cold plasma column of radius R and electron number density n immersed in an axial constant magnetic field. (author) 3 refs., 3 figs
Self-consistent adjoint analysis for topology optimization of electromagnetic waves
Deng, Yongbo; Korvink, Jan G.
2018-05-01
In topology optimization of electromagnetic waves, the Gâteaux differentiability of the conjugate operator to the complex field variable results in the complexity of the adjoint sensitivity, which evolves the original real-valued design variable to be complex during the iterative solution procedure. Therefore, the self-inconsistency of the adjoint sensitivity is presented. To enforce the self-consistency, the real part operator has been used to extract the real part of the sensitivity to keep the real-value property of the design variable. However, this enforced self-consistency can cause the problem that the derived structural topology has unreasonable dependence on the phase of the incident wave. To solve this problem, this article focuses on the self-consistent adjoint analysis of the topology optimization problems for electromagnetic waves. This self-consistent adjoint analysis is implemented by splitting the complex variables of the wave equations into the corresponding real parts and imaginary parts, sequentially substituting the split complex variables into the wave equations with deriving the coupled equations equivalent to the original wave equations, where the infinite free space is truncated by the perfectly matched layers. Then, the topology optimization problems of electromagnetic waves are transformed into the forms defined on real functional spaces instead of complex functional spaces; the adjoint analysis of the topology optimization problems is implemented on real functional spaces with removing the variational of the conjugate operator; the self-consistent adjoint sensitivity is derived, and the phase-dependence problem is avoided for the derived structural topology. Several numerical examples are implemented to demonstrate the robustness of the derived self-consistent adjoint analysis.
Nonstationary random acoustic and electromagnetic fields as wave diffusion processes
International Nuclear Information System (INIS)
Arnaut, L R
2007-01-01
We investigate the effects of relatively rapid variations of the boundaries of an overmoded cavity on the stochastic properties of its interior acoustic or electromagnetic field. For quasi-static variations, this field can be represented as an ideal incoherent and statistically homogeneous isotropic random scalar or vector field, respectively. A physical model is constructed showing that the field dynamics can be characterized as a generalized diffusion process. The Langevin-It o-hat and Fokker-Planck equations are derived and their associated statistics and distributions for the complex analytic field, its magnitude and energy density are computed. The energy diffusion parameter is found to be proportional to the square of the ratio of the standard deviation of the source field to the characteristic time constant of the dynamic process, but is independent of the initial energy density, to first order. The energy drift vanishes in the asymptotic limit. The time-energy probability distribution is in general not separable, as a result of nonstationarity. A general solution of the Fokker-Planck equation is obtained in integral form, together with explicit closed-form solutions for several asymptotic cases. The findings extend known results on statistics and distributions of quasi-stationary ideal random fields (pure diffusions), which are retrieved as special cases
Nonlinear Electromagnetic Waves and Spherical Arc-Polarized Waves in Space Plasmas
Tsurutani, B.; Ho, Christian M.; Arballo, John K.; Lakhina, Gurbax S.; Glassmeier, Karl-Heinz; Neubauer, Fritz M.
1997-01-01
We review observations of nonlinear plasma waves detected by interplanetary spacecraft. For this paper we will focus primarily on the phase-steepened properties of such waves. Plasma waves at comet Giacobini-Zinner measured by the International Cometary Explorer (ICE), at comets Halley and Grigg-Skjellerup measured by Giotto, and interplanetary Alfven waves measured by Ulysses, will be discussed and intercompared.
Xuyang, CHEN; Fangfang, SHEN; Yanming, LIU; Wei, AI; Xiaoping, LI
2018-06-01
A plasma-based stable, ultra-wideband electromagnetic (EM) wave absorber structure is studied in this paper for stealth applications. The stability is maintained by a multi-layer structure with several plasma layers and dielectric layers distributed alternately. The plasma in each plasma layer is designed to be uniform, whereas it has a discrete nonuniform distribution from the overall view of the structure. The nonuniform distribution of the plasma is the key to obtaining ultra-wideband wave absorption. A discrete Epstein distribution model is put forward to constrain the nonuniform electron density of the plasma layers, by which the wave absorption range is extended to the ultra-wideband. Then, the scattering matrix method (SMM) is employed to analyze the electromagnetic reflection and absorption of the absorber structure. In the simulation, the validation of the proposed structure and model in ultra-wideband EM wave absorption is first illustrated by comparing the nonuniform plasma model with the uniform case. Then, the influence of various parameters on the EM wave reflection of the plasma are simulated and analyzed in detail, verifying the EM wave absorption performance of the absorber. The proposed structure and model are expected to be superior in some realistic applications, such as supersonic aircraft.
Merger of binary neutron stars: Gravitational waves and electromagnetic counterparts
Energy Technology Data Exchange (ETDEWEB)
Shibata, Masaru
2016-12-15
Late inspiral and merger phases of binary neutron stars are the valuable new experimental fields for exploring nuclear physics because (i) gravitational waves from them will bring information for the neutron-star equation of state and (ii) the matter ejected after the onset of the merger could be the main site for the r-process nucleosynthesis. We will summarize these aspects of the binary neutron stars, describing the current understanding for the merger process of binary neutron stars that has been revealed by numerical-relativity simulations.
Electromagnetic generation of volume waves in RFe2 intermetallics
International Nuclear Information System (INIS)
Il'yasov, R.S.; Borovkova, M.A.
1996-01-01
Experimental results are presented on the phenomenon of electromagneto-acoustic transformation of longitudinal and cross waves in RFe 2 intermetallics. It is shown that in the range from the room temperature to Curie point the generation of ultrasound occurs only at the expense of one-ion anisotropic magnetostriction. In the vicinity of Curie point the contribution of isotropic magnetostriction of paraprocess is not observed. The quantitative interpretation is given to temperature and field dependences of electromagneto-acoustic transformation parameters. A noticeable temperature hysteresis of the above-mentioned transformation is revealed in ErFe 2 near the point of compensation. 7 refs.; 5 figs
The scattering properties of anisotropic dielectric spheres on electromagnetic waves
International Nuclear Information System (INIS)
Chen Hui; Zhang Weiyi; Wang Zhenlin; Ming Naiben
2004-01-01
The scattering coefficients of spheres with dielectric anisotropy are calculated analytically in this paper using the perturbation method. It is found that the different modes of vector spherical harmonics and polarizations are coupled together in the scattering coefficients (c-matrix) in contrast to the isotropic case where all modes are decoupled from each other. The generalized c-matrix is then incorporated into our codes for a vector wave multiple scattering program; the preliminary results on face centred cubic structure show that dielectric anisotropy reduces the symmetry of the scattering c-matrix and removes the degeneracy in photonic band structures composed of isotropic dielectric spheres
Sound absorption in a field of a strong electromagnetic wave in a quantizied magnetic field
International Nuclear Information System (INIS)
Chajkovskij, I.A.
1974-01-01
A coefficient of sound absorption GAMMA in a semiconductor and semi-metal in the quantized magnetic field is calculated for a system exposed to a field of strong electromagnetic radiation. The cases E parallel H and E orthogonal H are considered. Along with the already known strong oscillations of sound absorption in magnetic fields, the absorption spectrum GAMMAsub(par) and GAMMAsub(orth) shows new oscillations representing a manifestation of the quasi-energetic electron spectrum in the field of a strong electromagnetic wave. The oscillation height at E parallel H is modulated by the electromagnetic field. It is shown that the ratio GAMMAsub(par)/GAMMAsub(orth) allows the determination of the effective mass of the carriers
Effects of Millimeter-Wave Electromagnetic Radiation on the Experimental Model of Migraine.
Sivachenko, I B; Medvedev, D S; Molodtsova, I D; Panteleev, S S; Sokolov, A Yu; Lyubashina, O A
2016-02-01
Effects of millimeter-wave electromagnetic radiation (40 GHz frequency, 0.01 mW power) on the spontaneous fi ring of convergent neurons of the spinal trigeminal nucleus and their responses to electrical stimulation of the dura mater were studied in neurophysiological experiments on rats. Irradiation of the area of cutaneous receptive fields of spinal trigeminal nucleus reversibly inhibited both spontaneous discharges and activity induced by electrical stimulation of the dura mater. The second and third exposures to electromagnetic radiation with an interval of 10 min were ineffective. These results suggest that suppression of neuronal excitability in the spinal trigeminal ganglion can be a mechanism of the anti-migraine effects of electromagnetic radiation observed in clinical practice.
Statistical Thermodynamic Approach to Vibrational Solitary Waves in Acetanilide
Vasconcellos, Áurea R.; Mesquita, Marcus V.; Luzzi, Roberto
1998-03-01
We analyze the behavior of the macroscopic thermodynamic state of polymers, centering on acetanilide. The nonlinear equations of evolution for the populations and the statistically averaged field amplitudes of CO-stretching modes are derived. The existence of excitations of the solitary wave type is evidenced. The infrared spectrum is calculated and compared with the experimental data of Careri et al. [Phys. Rev. Lett. 51, 104 (1983)], resulting in a good agreement. We also consider the situation of a nonthermally highly excited sample, predicting the occurrence of a large increase in the lifetime of the solitary wave excitation.
Resonant absorption of electromagnetic waves in transition anisotropic media.
Kim, Kihong
2017-11-27
We study the mode conversion and resonant absorption phenomena occurring in a slab of a stratified anisotropic medium, optical axes of which are tilted with respect to the direction of inhomogeneity, using the invariant imbedding theory of wave propagation. When the tilt angle is zero, mode conversion occurs if the longitudinal component of the permittivity tensor, which is the one in the direction of inhomogeneity in the non-tilted case, varies from positive to negative values within the medium, while the transverse component plays no role. When the tilt angle is nonzero, the wave transmission and absorption show an asymmetry under the sign change of the incident angle in a range of the tilt angle, while the reflection is always symmetric. We calculate the reflectance, the transmittance and the absorptance for several configurations of the permittivity tensor and find that resonant absorption is greatly enhanced when the medium from the incident surface to the resonance region is hyperbolic than when it is elliptic. For certain configurations, the transmittance and absorptance curves display sharp peaks at some incident angles determined by the tilt angle.
Reciprocity in quantum, electromagnetic and other wave scattering
International Nuclear Information System (INIS)
Deák, L.; Fülöp, T.
2012-01-01
The reciprocity principle is that, when an emitted wave gets scattered on an object, the scattering transition amplitude does not change if we interchange the source and the detector—in other words, if incoming waves are interchanged with appropriate outgoing ones. Reciprocity is sometimes confused with time reversal invariance, or with invariance under the rotation that interchanges the location of the source and the location of the detector. Actually, reciprocity covers the former as a special case, and is fundamentally different from–but can be usefully combined with–the latter. Reciprocity can be proved as a theorem in many situations and is found violated in other cases. The paper presents a general treatment of reciprocity, discusses important examples, shows applications in the field of photon (Mössbauer) scattering, and establishes a fruitful connection with a recently developing area of mathematics. - Highlights: ► A frame independent generalized reciprocity theorem of scattering theory is given. ► Reciprocity for two spin/polarization degrees of freedom is detailed. ► Relationship of reciprocity to time reversal and to 180 degree rotation is discussed. ► Reciprocal and nonreciprocal settings in Mossbauer spectroscopy are studied. ► The symmetry of diffuse omega-scans is explained with the aid of reciprocity.
International Nuclear Information System (INIS)
Bhattacharyya, B.; Chakraborty, B.
1979-01-01
Nonlinear corrections of a left and a right circularly polarized electromagnetic wave of the same frequency, propagating in the direction of a static and uniform magnetic field in a cold and collisionally damped two-component plasma, have been evaluated. The nonlinearly correct dispersion relation, self-generating nonlinear precessional rotation of the polarization ellipse of the wave and the shift in a wave parameter depend on linear combinations of products of the amplitude components taken two at a time and hence on the energies of the waves. Both in the low frequency resonance (that is when the ion cyclotron frequency equals the wave frequency) and in the high frequency resonance (that is when the electron cyclotron frequency equals the wave frequency), the self-precessional rate and wavenumber shift are found to be large and so have the possibility of detection in laboratory experiments. Moreover, for the limit leading to Alfven waves, these nonlinear effects have been found to have some interesting and significant properties. (Auth.)
Kim, Hyomin; Clauer, C. Robert; Gerrard, Andrew J.; Engebretson, Mark J.; Hartinger, Michael D.; Lessard, Marc R.; Matzka, Jürgen; Sibeck, David G.; Singer, Howard J.; Stolle, Claudia; Weimer, Daniel R.; Xu, Zhonghua
2017-07-01
We report on simultaneous observations of electromagnetic ion cyclotron (EMIC) waves associated with traveling convection vortex (TCV) events caused by transient solar wind dynamic pressure (Pd) impulse events. The Time History of Events and Macroscale Interactions during Substorms (THEMIS) spacecraft located near the magnetopause observed radial fluctuations of the magnetopause, and the GOES spacecraft measured sudden compressions of the magnetosphere in response to sudden increases in Pd. During the transient events, EMIC waves were observed by interhemispheric conjugate ground-based magnetometer arrays as well as the GOES spacecraft. The spectral structures of the waves appear to be well correlated with the fluctuating motion of the magnetopause, showing compression-associated wave generation. In addition, the wave features are remarkably similar in conjugate hemispheres in terms of bandwidth, quasiperiodic wave power modulation, and polarization. Proton precipitation was also observed by the DMSP spacecraft during the wave events, from which the wave source region is estimated to be 72°-74° in magnetic latitude, consistent with the TCV center. The confluence of space-borne and ground instruments including the interhemispheric, high-latitude, fluxgate/induction coil magnetometer array allows us to constrain the EMIC source region while also confirming the relationship between EMIC waves and the TCV current system.
The interaction of an electromagnetic wave with an inhomogeneous plasma slab
International Nuclear Information System (INIS)
Lacina, J.; Preinhaelter, J.
1982-07-01
In connection with the problem of plasma heating by high-frequency waves a numerical code was developed which makes it possible to study the incidence of an electromagnetic wave on an inhomogeneous plasma slab. Using a one-dimensional model, non-magnetized plasma is described by means of two-fluid equations with finite electron pressure and with the adiabatic condition for all processes. It is shown that at normal incidence of a wave on a cold plasma, the wave is reflected from the region of plasma resonance. A standing wave arises which generates an electrostatic standing wave of a double frequency. At the same time the density gradient sharply rises in this region. In a warm plasma the incident wave again creates a standing wave but nonlinear perturbations propagate from the region of plasma resonance at ion acoustic velocity to the whole plasma volume. In this case the density gradient does not change very much. In the region of plasma resonance ion acoustic waves are also generated. (author)
Lorentz invariance violation and simultaneous emission of electromagnetic and gravitational waves
Directory of Open Access Journals (Sweden)
E. Passos
2017-09-01
Full Text Available In this work, we compute some phenomenological bounds for the electromagnetic and massive gravitational high-derivative extensions supposing that it is possible to have an astrophysical process that generates simultaneously gravitational and electromagnetic waves. We present Lorentz invariance violating (LIV higher-order derivative models, following the Myers–Pospelov approach, to electrodynamics and massive gravitational waves. We compute the corrected equation of motion of these models, their dispersion relations and the velocities. The LIV parameters for the gravitational and electromagnetic sectors, ξg and ξγ, respectively, were also obtained for three different approaches: luminal photons, time delay of flight and the difference of graviton and photon velocities. These LIV parameters depend on the mass scales where the LIV-terms become relevant, M for the electromagnetic sector and M1 for the gravitational one. We obtain, using the values for M and M1 found in the literature, that ξg∼10−2, which is expected to be phenomenologically relevant and ξγ∼103, which cannot be suitable for an effective LIV theory. However, we show that ξγ can be interesting in a phenomenological point of view if M≫M1. Finally the relation between the variation of the velocities of the photon and the graviton in relation to the speed of light was calculated and resulted in Δvg/Δvγ≲1.82×10−3.
International Nuclear Information System (INIS)
Mohammad Syahmi Nordin; Fauziah Abdul Aziz
2007-01-01
The low resolution Automatic Picture Transmission (APT) data from the National Oceanic and Atmospheric Administration (NOAA) polar-orbiting satellites Advanced Very High Resolution Radiometer (AVHRR) is being received and recorded in real-time mode at ground receiving station in School of Science and Technology, Universiti Malaysia Sabah. The system is suitable for the developing and undeveloped countries in south and Southeast Asia and is said to be acceptable for engineering, agricultural, climatological and environmental applications. The system comprises a personal computer attached with a small APT receiver. The data transmission between the ground receiving station and NOAA satellites is using the electromagnetic wave. The relation for receiving and processing the electromagnetic wave in the transmission will be discussed. (Author)
On the Possibility of the Existence of a Surface Electromagnetic Wave in the Permafrost Area
Balkhanov, V. K.; Bashkuev, Yu. B.; Advokatov, V. R.
2018-01-01
The results of measurements of the vertical component of electric field at a radio path with the permafrost at a frequency of 255 kHz have been interpreted. An analysis of the results has shown that the considered radio path exhibits the properties of a two-part impedance surface, i.e., it consists of two sections. At a distance of 70 km from a radiation source and at a frequency of 255 kHz of the electromagnetic wave, the field decreases with the distance R according to the power law as R -1.5 and a power index takes an intermediate value between the power indices for decreasing the field in free space R -2 and for the decrease in the field above an ideal conducting surface R -1. With further propagation at a distance of 70-220 km, the field shows the specific behavior of a surface electromagnetic wave.
The involvement of cutaneous receptors in the biological effects of electromagnetic millimeter waves
Directory of Open Access Journals (Sweden)
Anton Emil
2014-01-01
Full Text Available The involvement of peripheral nerve terminations in the mechanisms of action of electromagnetic millimeter waves (mmW was assessed. It is currently thought that mmW could be used in noninvasive complementary therapy because of their analgesic effect. However, the mechanisms of their antinociceptive effect and non-ionizing radiation are the subjects of controversy. The mechanisms of interaction of mmW and the cutaneous tissue have not been elucidated. We observed mast cell degranulation at the place of mmW action, a decrease of chronaxie and Turck reflex time, an increase in the number of afferent impulses after sciatic nerve at stimulation, as well as an increase electrocardiogram R-R interval of isolated frog heart after application of mmW. Based on these investigations, we propose that electromagnetic waves of millimeter length modify, through indirect mechanisms, the excitability and reactivity of peripheral nerve terminations.
The electromagnetic wave energy effect(s) in microwave-assisted organic syntheses (MAOS).
Horikoshi, Satoshi; Watanabe, Tomoki; Narita, Atsushi; Suzuki, Yumiko; Serpone, Nick
2018-03-26
Organic reactions driven by microwaves have been subjected for several years to some enigmatic phenomenon referred to as the microwave effect, an effect often mentioned in microwave chemistry but seldom understood. We identify this microwave effect as an electromagnetic wave effect that influences many chemical reactions. In this article, we demonstrate its existence using three different types of microwave generators with dissimilar oscillation characteristics. We show that this effect is operative in photocatalyzed TiO 2 reactions; it negatively influences electro-conductive catalyzed reactions, and yet has but a negligible effect on organic syntheses. The relationship between this electromagnetic wave effect and chemical reactions is elucidated from such energetic considerations as the photon energy and the reactions' activation energies.
Beta Decay in the Field of an Electromagnetic Wave and Experiments on Measuring the Neutrino Mass
International Nuclear Information System (INIS)
Dorofeev, O.F.; Lobanov, A.E.
2005-01-01
Investigations of the effect of an electromagnetic wave field on the beta-decay process are used to analyze the tritium-decay experimental data on the neutrino mass. It is shown that the electromagnetic wave can distort the beta spectrum, shifting the end point to the higher energy region. This phenomenon is purely classical and it is associated with the electron acceleration in the radiation field. Since strong magnetic fields exist in setups for precise measurement of the neutrino mass, the indicated field can appear owing to the synchrotron radiation mechanism. The phenomenon under consideration can explain the experimentally observed anomalies in the spectrum of the decay electrons; in particular, the effect of the 'negative square of the neutrino mass'
International Nuclear Information System (INIS)
Kavitha, L.; Saravanan, M.; Srividya, B.; Gopi, D.
2011-01-01
We investigate the nature of propagation of electromagnetic waves (EMWs) in an antiferromagnetic medium with Dzyaloshinsky-Moriya (DM) interaction environment. The interplay of bilinear and DM exchange spin coupling with the magnetic field component of the EMW has been studied by solving Maxwell's equations coupled with a nonlinear spin equation for the magnetization of the medium. We made a nonuniform expansion of the magnetization and magnetic field along the direction of propagation of EMW, in the framework of reductive perturbation method, and the dynamics of the system is found to be governed by a generalized derivative nonlinear Schroedinger (DNLS) equation. We employ the Jacobi-elliptic function method to solve the DNLS equation, and the electromagnetic wave propagation in an antiferromagnetic medium is governed by the breatherlike spatially and temporally coherent localized modes under the influence of DM interaction parameter.
Magnetic Field Effects and Electromagnetic Wave Propagation in Highly Collisional Plasmas.
Bozeman, Steven Paul
The homogeneity and size of radio frequency (RF) and microwave driven plasmas are often limited by insufficient penetration of the electromagnetic radiation. To investigate increasing the skin depth of the radiation, we consider the propagation of electromagnetic waves in a weakly ionized plasma immersed in a steady magnetic field where the dominant collision processes are electron-neutral and ion-neutral collisions. Retaining both the electron and ion dynamics, we have adapted the theory for cold collisionless plasmas to include the effects of these collisions and obtained the dispersion relation at arbitrary frequency omega for plane waves propagating at arbitrary angles with respect to the magnetic field. We discuss in particular the cases of magnetic field enhanced wave penetration for parallel and perpendicular propagation, examining the experimental parameters which lead to electromagnetic wave propagation beyond the collisional skin depth. Our theory predicts that the most favorable scaling of skin depth with magnetic field occurs for waves propagating nearly parallel to B and for omega << Omega_{rm e} where Omega_{rm e} is the electron cyclotron frequency. The scaling is less favorable for propagation perpendicular to B, but the skin depth does increase for this case as well. Still, to achieve optimal wave penetration, we find that one must design the plasma configuration and antenna geometry so that one generates primarily the appropriate angles of propagation. We have measured plasma wave amplitudes and phases using an RF magnetic probe and densities using Stark line broadening. These measurements were performed in inductively coupled plasmas (ICP's) driven with a standard helical coil, a reverse turn (Stix) coil, and a flat spiral coil. Density measurements were also made in a microwave generated plasma. The RF magnetic probe measurements of wave propagation in a conventional ICP with wave propagation approximately perpendicular to B show an increase in
Improved heat transfer modeling of the eye for electromagnetic wave exposures.
Hirata, Akimasa
2007-05-01
This study proposed an improved heat transfer model of the eye for exposure to electromagnetic (EM) waves. Particular attention was paid to the difference from the simplified heat transfer model commonly used in this field. From our computational results, the temperature elevation in the eye calculated with the simplified heat transfer model was largely influenced by the EM absorption outside the eyeball, but not when we used our improved model.
The Effect of Electromagnetic Waves on the General Health of Zahedan Gas Power Plant Personnel
Directory of Open Access Journals (Sweden)
Fereydoon Laal
2016-08-01
Full Text Available Abstract Introduction: With ever improving technology and increasing the use of high voltage power in industrial environments, concerns about the destructive effects of electromagnetic waves on human health have increased. Thus the present study aims to evaluate the effects of electromagnetic waves on the general health of Zahedan gas power plant personnel. Materials & Method: The present case-control study investigated the health of people at one point of time and their amount of exposure to electromagnetic waves at the same time. The data collection tool in this study was 28-item general health questionnaire (GHQ-28. After measuring the electromagnetic waves at distances of 1, 1.5 and 3 meters at high voltage power substations and data extraction, the data were entered to SPSS software and analyzed by descriptive statistics, t-test and chi-square. Results: In this study, the age and experience variables were not significantly different in two groups (p> 0.05. The highest magnetic fields in high voltage power substations was at a distance of 1 meter in the substation 607 (28/1 mG and in precision tool work units (7.03 mG. The results showed that the depressive and general health symptoms were significantly different between the exposed and unexposed groups (p = 0.04, however the difference was not significant in terms of physical performance, anxiety and social performance (p> 0.05. Conclusion: although the level of exposure was lower than standard level determined in Iran, the significant difference of the general health and depression between the two groups, explains the necessity of conducting more studies in this regard. Also by reducing the exposure time and increasing people’s awareness it is possible to take important steps to reduce exposure and complications.
Energy Technology Data Exchange (ETDEWEB)
Aiello, Matias; Bengochea, Gabriel R; Ferraro, Rafael, E-mail: aiello@iafe.uba.ar, E-mail: gabriel@iafe.uba.ar, E-mail: ferraro@iafe.uba.ar [Instituto de Astronomia y Fisica del Espacio, Casilla de Correo 67, Sucursal 28, 1428 Buenos Aires (Argentina); Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellon I, 1428 Buenos Aires (Argentina)
2008-06-15
Born-Infeld electromagnetic waves interacting with a static magnetic background in an expanding universe are studied. The non-linear character of Born-Infeld electrodynamics modifies the relation between the energy flux and the distance to the source, which gains a new dependence on the redshift that is governed by the background field. We compute the luminosity distance as a function of the redshift and compare with Maxwellian curves for supernovae type Ia.
On the theory of interaction of electromagnetic waves with Bose-Einstein magnon condensate
International Nuclear Information System (INIS)
Loktev, V.M.
2008-01-01
An attempt is made to analyze the dependence of the Raman scattering cross section or the absorption/emission of electromagnetic waves by a Bose-Einstein condensate of magnons on their (magnons) density. Specifically, the intensities of one- and two-magnon transitions are compared and it is concluded that latter dominate in a Bose condensate. The salient features and possible role of the inter-magnon interaction are discussed briefly
The Fermionic Signature Operator and Hadamard States in the Presence of a Plane Electromagnetic Wave
Finster, Felix; Reintjes, Moritz
2017-05-01
We give a non-perturbative construction of a distinguished state for the quantized Dirac field in Minkowski space in the presence of a time-dependent external field of the form of a plane electromagnetic wave. By explicit computation of the fermionic signature operator, it is shown that the Dirac operator has the strong mass oscillation property. We prove that the resulting fermionic projector state is a Hadamard state.
Perturbation theory for the Bethe-Salpeter equation in the field of a plane electromagnetic wave
International Nuclear Information System (INIS)
Starostin, V.S.; Litskevich, I.K.
1990-01-01
The completeness and orthogonality of the solutions of the Bethe-Salpeter equation is proven. A correct derivation of perturbation-theory equations is given. A generalization that includes the field of a plane electromagnetic wave is proposed. The rate of one-photon annihilation of positronium in this field is calculated. If the one-photon decay is allowed, the stationary states of the system are found (states of light-positronium)
Egorov, V. A.; Makarov, G. I.
2006-12-01
[1] The influence of vegetable cover on propagation ofelectromagnetic waves in the Earth-ionosphere wave channel isstudied in the scope of the model of a homogeneous isotropic``forest layer'' with effective value of the dielectric permeabilityɛf=1.2 and electric conductivityσf (t oC)depending on theenvironmental temperature according to the results obtained in thispaper. It is shown that the character of the electromagnetic fieldbehavior in the presence of large forests is of a well-pronouncedseasonal character additionally complicated by the diurnalvariations of the field depending on the environmental temperaturevariations.
Nonlinear propagation of electromagnetic waves in negative-refraction-index composite materials.
Kourakis, I; Shukla, P K
2005-07-01
We investigate the nonlinear propagation of electromagnetic waves in left-handed materials. For this purpose, we consider a set of coupled nonlinear Schrödinger (CNLS) equations, which govern the dynamics of coupled electric and magnetic field envelopes. The CNLS equations are used to obtain a nonlinear dispersion, which depicts the modulational stability profile of the coupled plane-wave solutions in left-handed materials. An exact (in)stability criterion for modulational interactions is derived, and analytical expressions for the instability growth rate are obtained.
On the creation of gravitational wave by photon in external electromagnetic field
International Nuclear Information System (INIS)
Hoang Ngoc Long; Le Khac Huong
1989-08-01
The creation of the gravitational wave by the photon in an electromagnetic field is considered. We show that when the momentum of the photon is perpendicular to the field, the probability of the gravitational wave creation is largest in the direction of the motion of the photon. A numerical evaluation shows that the probability of creation in the direction mentioned is much larger than that in the direction considered, namely in the direction perpendicular to the photon momentum and may have the observable value in the present technical conditions. (author). 10 refs
Dispersion relation of electromagnetic waves in one-dimensional plasma photonic crystals
International Nuclear Information System (INIS)
Hojo, Hitoshi; Mase, Atsushi
2004-01-01
The dispersion relation of electromagnetic waves in one-dimensional plasma photonic crystals is studied. The plasma photonic crystal is a periodic array composed of alternating thin plasma and dielectric material. The dispersion relation is obtained by solving a Maxwell wave equation using a method analogous to Kronig-Penny's problem in quantum mechanics, and it is found that the frequency gap and cut-off appear in the dispersion relation. The frequency gap is shown to become larger with the increase of the plasma density as well as plasma width. (author)
Nonlinear gyrokinetic equations for low-frequency electromagnetic waves in general plasma equilibria
International Nuclear Information System (INIS)
Frieman, E.A.; Chen, L.
1981-10-01
A nonlinear gyrokinetic formalism for low-frequency (less than the cyclotron frequency) microscopic electromagnetic perturbations in general magnetic field configurations is developed. The nonlinear equations thus derived are valid in the strong-turbulence regime and contain effects due to finite Larmor radius, plasma inhomogeneities, and magentic field geometries. The specific case of axisymmetric tokamaks is then considered, and a model nonlinear equation is derived for electrostatic drift waves. Also, applying the formalism to the shear Alfven wave heating sceme, it is found that nonlinear ion Landau damping of kinetic shear-Alfven waves is modified, both qualitatively and quantitatively, by the diamagnetic drift effects. In particular, wave energy is found to cascade in wavenumber instead of frequency
A Numerical Study on the Screening of Blast-Induced Waves for Reducing Ground Vibration
Park, Dohyun; Jeon, Byungkyu; Jeon, Seokwon
2009-06-01
Blasting is often a necessary part of mining and construction operations, and is the most cost-effective way to break rock, but blasting generates both noise and ground vibration. In urban areas, noise and vibration have an environmental impact, and cause structural damage to nearby structures. Various wave-screening methods have been used for many years to reduce blast-induced ground vibration. However, these methods have not been quantitatively studied for their reduction effect of ground vibration. The present study focused on the quantitative assessment of the effectiveness in vibration reduction of line-drilling as a screening method using a numerical method. Two numerical methods were used to analyze the reduction effect toward ground vibration, namely, the “distinct element method” and the “non-linear hydrocode.” The distinct element method, by particle flow code in two dimensions (PFC 2D), was used for two-dimensional parametric analyses, and some cases of two-dimensional analyses were analyzed three-dimensionally using AUTODYN 3D, the program of the non-linear hydrocode. To analyze the screening effectiveness of line-drilling, parametric analyses were carried out under various conditions, with the spacing, diameter of drill holes, distance between the blasthole and line-drilling, and the number of rows of drill holes, including their arrangement, used as parameters. The screening effectiveness was assessed via a comparison of the vibration amplitude between cases both with and without screening. Also, the frequency distribution of ground motion of the two cases was investigated through fast Fourier transform (FFT), with the differences also examined. From our study, it was concluded that line-drilling as a screening method of blast-induced waves was considerably effective under certain design conditions. The design details for field application have also been proposed.
Modified Clemmow-Mullaly-Allis diagram for large-amplitude electromagnetic waves in magnetoplasmas
International Nuclear Information System (INIS)
Minami, K.; Mori, Y.; Takeda, S.
1975-02-01
A possible modification to the well known Clemmow- Mullaly-Allis diagram is analysed taking into account the radiation pressure force due to a large-amplitude electromagnetic field E in magnetoplasmas. We restrict ourselves here to the propagations parallel (the right and left-hand circularly polarized waves) and/or perpendicular (the ordinary and extraordinary modes) to the static magnetic field Bsub(o). We analyse electromagnetic waves incident normally on a semi-infinite uniform plasma, on which Bsub(o) is applied parallel and/or perpendicular to the surface. Considerations are limited to a cold collisionless plasma where the incident waves are evanescent. Simple expressions are obtained for the cut-off conditions of the waves except the extraordinary mode. In the latter case, the cut-off condition is calculated numerically solving an integral equation. The results are demonstrated in the usual Clemmow-Mullaly-Allis diagram for the various values of b=2Esub(i) 2 e 2 /mω 2 kappaTsub(e') where Esub(i) and ω are, respectively, the amplitude and the angular frequency of the incident wave. The cut-off lines are shown to move towards the higher densities with increasing b. (auth.)
International Nuclear Information System (INIS)
Yang Min; Li Xiaoping; Xie Kai; Liu Donglin; Liu Yanming
2013-01-01
A large volume uniform plasma generator is proposed for the experiments of electromagnetic (EM) wave propagation in plasma, to reproduce a “black out” phenomenon with long duration in an environment of the ordinary laboratory. The plasma generator achieves a controllable approximate uniform plasma in volume of 260 mm× 260 mm× 180 mm without the magnetic confinement. The plasma is produced by the glow discharge, and the special discharge structure is built to bring a steady approximate uniform plasma environment in the electromagnetic wave propagation path without any other barriers. In addition, the electron density and luminosity distributions of plasma under different discharge conditions were diagnosed and experimentally investigated. Both the electron density and the plasma uniformity are directly proportional to the input power and in roughly reverse proportion to the gas pressure in the chamber. Furthermore, the experiments of electromagnetic wave propagation in plasma are conducted in this plasma generator. Blackout phenomena at GPS signal are observed under this system and the measured attenuation curve is of reasonable agreement with the theoretical one, which suggests the effectiveness of the proposed method.
Damez, Jean-Louis; Clerjon, Sylvie
2013-12-01
The meat industry needs reliable meat quality information throughout the production process in order to guarantee high-quality meat products for consumers. Besides laboratory researches, food scientists often try to adapt their tools to industrial conditions and easy handling devices useable on-line and in slaughterhouses already exist. This paper overviews the recently developed approaches and latest research efforts related to assessing the quality of different meat products by electromagnetic waves and examines the potential for their deployment. The main meat quality traits that can be assessed using electromagnetic waves are sensory characteristics, chemical composition, physicochemical properties, health-protecting properties, nutritional characteristics and safety. A wide range of techniques, from low frequency, high frequency impedance measurement, microwaves, NMR, IR and UV light, to X-ray interaction, involves a wide range of physical interactions between the electromagnetic wave and the sample. Some of these techniques are now in a period of transition between experimental and applied utilization and several sensors and instruments are reviewed. Copyright © 2013 Elsevier Ltd. All rights reserved.
Energy Technology Data Exchange (ETDEWEB)
Yu, Hao; Gu, Bao-Min; Wang, Yong-Qiang; Liu, Yu-Xiao [Institute of Theoretical Physics, Lanzhou University, Lanzhou 730000 (China); Huang, Fa Peng [Theoretical Physics Division, Institute of High Energy Physics, Chinese Academy of Sciences, P.O. Box 918-4, Beijing 100049 (China); Meng, Xin-He, E-mail: yuh13@lzu.edu.cn, E-mail: gubm15@lzu.edu.cn, E-mail: huangfp@ihep.ac.cn, E-mail: yqwang@lzu.edu.cn, E-mail: xhm@nankai.edu.cn, E-mail: liuyx@lzu.edu.cn [School of Physics, Nankai University, Tianjin 300071 (China)
2017-02-01
The future gravitational wave (GW) observations of compact binaries and their possible electromagnetic counterparts may be used to probe the nature of the extra dimension. It is widely accepted that gravitons and photons are the only two completely confirmed objects that can travel along null geodesics in our four-dimensional space-time. However, if there exist extra dimensions and only GWs can propagate freely in the bulk, the causal propagations of GWs and electromagnetic waves (EMWs) are in general different. In this paper, we study null geodesics of GWs and EMWs in a five-dimensional anti-de Sitter space-time in the presence of the curvature of the universe. We show that for general cases the horizon radius of GW is longer than EMW within equal time. Taking the GW150914 event detected by the Advanced Laser Interferometer Gravitational-Wave Observatory and the X-ray event detected by the Fermi Gamma-ray Burst Monitor as an example, we study how the curvature k and the constant curvature radius l affect the horizon radii of GW and EMW in the de Sitter and Einstein-de Sitter models of the universe. This provides an alternative method for probing extra dimension through future GW observations of compact binaries and their electromagnetic counterparts.
Ryu, Seongwoo; Mo, Chan Bin; Lee, Haeshin; Hong, Soon Hyung
2013-11-01
Since carbon nanotube (CNT) was first discovered in 1991, it has been considered as a viable type of conductive filler for electromagnetic wave absorption materials in the GHz range. In this paper, pearl-necklace-structure CNT/Ni nano-powders were fabricated by a polyol process as conductive fillers. Compared to synthesized CNT, pearl-necklace Ni-decorated CNT increased the electrical conductivity by an order of 1 due to the enhancement of the Ni-conductive network. Moreover, the decorated Ni particles prevented the agglomeration of CNTs by counterbalancing the Van der Walls interaction between the CNTs. A CNT/Ni nanocomposite showed a homogeneous dispersion in an epoxy-based matrix. This enhanced physical morphology and electrical properties lead to an increase in the loss tangent and reflection loss in the CNT/Ni/Epoxy nanocomposite compared to these characteristics of a CNT/Epoxy nanocomposite in range of 8-12 GHz. The electromagnetic wave absorption properties of CNT/Ni/epoxy nanocomposites will provide enormous opportunities for electronic applications where lightweight EMI shielding or electro-magnetic wave absorption properties are necessary.
Focusing Leaky Waves: A Class of Electromagnetic Localized Waves with Complex Spectra
Fuscaldo, Walter; Comite, Davide; Boesso, Alessandro; Baccarelli, Paolo; Burghignoli, Paolo; Galli, Alessandro
2018-05-01
Localized waves, i.e., the wide class of limited-diffraction, limited-dispersion solutions to the wave equation are generally characterized by real wave numbers. We consider the role played by localized waves with generally complex "leaky" wave numbers. First, the impact of the imaginary part of the wave number (i.e., the leakage constant) on the diffractive (spatial broadening) features of monochromatic localized solutions (i.e., beams) is rigorously evaluated. Then general conditions are derived to show that only a restricted class of spectra (either real or complex) allows for generating a causal localized wave. It turns out that backward leaky waves fall into this category. On this ground, several criteria for the systematic design of wideband radiators, namely, periodic radial waveguides based on backward leaky waves, are established in the framework of leaky-wave theory. An effective design method is proposed to minimize the frequency dispersion of the proposed class of devices and the impact of the "leakage" on the dispersive (temporal broadening) features of polychromatic localized solutions (i.e., pulses) is accounted for. Numerical results corroborate the concept, clearly highlighting the advantages and limitations of the leaky-wave approach for the generation of localized pulses at millimeter-wave frequencies, where energy focusing is in high demand in modern applications.
Electromagnetic Wave Transmittance Control using Anisotropic Plasma Lattice
Matlis, Eric; Corke, Thomas; Hoffman, Anthony
2017-11-01
Experiments of transmission through a lattice array of plasma columns have shown an absorption band close to the plasma frequency at 14 GHz. The beam was oriented at a 35° incident angle to the planar plasma cell. These experiments were designed to determine if the observed absorption was the result of the isotropic plasma medium or that of an anisotropic metamaterial. Transmission of the microwave energy was not consistent with an isotropic material in which absorption would monotonically increase below the plasma frequency. The experimental results are supported by an anisotropic model which was developed for the plasma permittivity using an effective medium approximation. The plasma columns were modeled as uniform rods with permittivity described by a Drude model while the components of the permittivity tensor was calculated using the Maxwell-Garnett effective medium theory. Electron densities of n = 4 x1012 cm-3 were assumed which is consistent with prior experimental measurements. This model confirms the existence of non-zero imaginary wave vector k in a narrow region centered about 14 GHz.
New aspects of whistler waves driven by an electron beam studied by a 3-D electromagnetic code
Nishikawa, Ken-Ichi; Buneman, Oscar; Neubert, Torsten
1994-01-01
We have restudied electron beam driven whistler waves with a 3-D electromagnetic particle code. The simulation results show electromagnetic whistler wave emissions and electrostatic beam modes like those observed in the Spacelab 2 electron beam experiment. It has been suggested in the past that the spatial bunching of beam electrons associated with the beam mode may directly generate whistler waves. However, the simulation results indicate several inconsistencies with this picture: (1) whistler waves continue to be generated even after the beam mode space charge modulation looses its coherence, (2) the parallel (to the background magnetic field) wavelength of the whistler wave is longer than that of the beam instability, and (3) the parallel phase velocity of the whistler wave is smaller than that of the beam mode. The complex structure of the whistler waves in the vicinity of the beam suggest that the transverse motion (gyration) of the beam and background electrons is also involved in the generation of whistler waves.
Acoustic Pressure Waves in Vibrating 3-D Laminated Beam-Plate Enclosures
Directory of Open Access Journals (Sweden)
Charles A. Osheku
2009-01-01
Full Text Available The effect of structural vibration on the propagation of acoustic pressure waves through a cantilevered 3-D laminated beam-plate enclosure is investigated analytically. For this problem, a set of well-posed partial differential equations governing the vibroacoustic wave interaction phenomenon are formulated and matched for the various vibrating boundary surfaces. By employing integral transforms, a closed form analytical expression is computed suitable for vibroacoustic modeling, design analysis, and general aerospace defensive applications. The closed-form expression takes the form of a kernel of polynomials for acoustic pressure waves showing the influence of linear interface pressure variation across the axes of vibrating boundary surfaces. Simulated results demonstrate how the mode shapes and the associated natural frequencies can be easily computed. It is shown in this paper that acoustic pressure waves propagation are dynamically stable through laminated enclosures with progressive decrement in interfacial pressure distribution under the influence of high excitation frequencies irrespective of whether the induced flow is subsonic, sonic , supersonic, or hypersonic. Hence, in practice, dynamic stability of hypersonic aircrafts or jet airplanes can be further enhanced by replacing their noise transmission systems with laminated enclosures.
Vibration isolation design for periodically stiffened shells by the wave finite element method
Hong, Jie; He, Xueqing; Zhang, Dayi; Zhang, Bing; Ma, Yanhong
2018-04-01
Periodically stiffened shell structures are widely used due to their excellent specific strength, in particular for aeronautical and astronautical components. This paper presents an improved Wave Finite Element Method (FEM) that can be employed to predict the band-gap characteristics of stiffened shell structures efficiently. An aero-engine casing, which is a typical periodically stiffened shell structure, was employed to verify the validation and efficiency of the Wave FEM. Good agreement has been found between the Wave FEM and the classical FEM for different boundary conditions. One effective wave selection method based on the Wave FEM has thus been put forward to filter the radial modes of a shell structure. Furthermore, an optimisation strategy by the combination of the Wave FEM and genetic algorithm was presented for periodically stiffened shell structures. The optimal out-of-plane band gap and the mass of the whole structure can be achieved by the optimisation strategy under an aerodynamic load. Results also indicate that geometric parameters of stiffeners can be properly selected that the out-of-plane vibration attenuates significantly in the frequency band of interest. This study can provide valuable references for designing the band gaps of vibration isolation.
Kelley, Luke Zoltan; Mandel, Ilya; Ramirez-Ruiz, Enrico
2013-06-01
The detection of an electromagnetic transient which may originate from a binary neutron star merger can increase the probability that a given segment of data from the LIGO-Virgo ground-based gravitational-wave detector network contains a signal from a binary coalescence. Additional information contained in the electromagnetic signal, such as the sky location or distance to the source, can help rule out false alarms and thus lower the necessary threshold for a detection. Here, we develop a framework for determining how much sensitivity is added to a gravitational-wave search by triggering on an electromagnetic transient. We apply this framework to a variety of relevant electromagnetic transients, from short gamma-ray bursts (GRBs) to signatures of r-process heating to optical and radio orphan afterglows. We compute the expected rates of multimessenger observations in the advanced detector era and find that searches triggered on short GRBs—with current high-energy instruments, such as Fermi—and nucleosynthetic “kilonovae”—with future optical surveys, like the Large Synoptic Survey Telescope—can boost the number of multimessenger detections by 15% and 40%, respectively, for a binary neutron star progenitor model. Short GRB triggers offer precise merger timing but suffer from detection rates decreased by beaming and the high a priori probability that the source is outside the LIGO-Virgo sensitive volume. Isotropic kilonovae, on the other hand, could be commonly observed within the LIGO-Virgo sensitive volume with an instrument roughly an order of magnitude more sensitive than current optical surveys. We propose that the most productive strategy for making multimessenger gravitational-wave observations is using triggers from future deep, optical all-sky surveys, with characteristics comparable to the Large Synoptic Survey Telescope, which could make as many as ten such coincident observations a year.
Energy Technology Data Exchange (ETDEWEB)
Abramov, Arnold, E-mail: qulaser@gmail.com [Kuang-Chi Institute of Advanced Technology, Shenzhen, 518057 (China); Kostikov, Alexander [Donbass State Engineering Academy, 84303, Kramatorsk, Donetsk (Ukraine)
2017-03-26
We report the effect of scattering of electromagnetic plane waves by two cylinders on whispering gallery mode (WGM) formation in a cylinder. WGM can occur because of the presence of additional cylinder scatterers at specific location, while WGMs can only form in a single cylinder for specific cylinder radius and/or wavelength values, the matching accuracy required would be much greater than that required in our model for the additional cylinders locations. Analysis of the general solution to the problem showed that the effect can be explained by the interference of waves scattered by additional cylinders and incident on the main cylinder. - Highlights: • We consider scattering of electromagnetic plane waves by two cylinders. • WGMs occur because of the presence of additional cylinder at specific location. • The accuracy for the locations is much less than required for specific values of single cylinder. • The interference of waves scattered by additional cylinders and incident on the main is responsible for the effect.
Electromagnetic Wave Propagation in Two-Dimensional Photonic Crystals
Energy Technology Data Exchange (ETDEWEB)
Foteinopoulou, Stavroula [Iowa State Univ., Ames, IA (United States)
2003-01-01
In this dissertation, they have undertaken the challenge to understand the unusual propagation properties of the photonic crystal (PC). The photonic crystal is a medium where the dielectric function is periodically modulated. These types of structures are characterized by bands and gaps. In other words, they are characterized by frequency regions where propagation is prohibited (gaps) and regions where propagation is allowed (bands). In this study they focus on two-dimensional photonic crystals, i.e., structures with periodic dielectric patterns on a plane and translational symmetry in the perpendicular direction. They start by studying a two-dimensional photonic crystal system for frequencies inside the band gap. The inclusion of a line defect introduces allowed states in the otherwise prohibited frequency spectrum. The dependence of the defect resonance state on different parameters such as size of the structure, profile of incoming source, etc., is investigated in detail. For this study, they used two popular computational methods in photonic crystal research, the Finite Difference Time Domain method (FDTD) and the Transfer Matrix Method (TMM). The results for the one-dimensional defect system are analyzed, and the two methods, FDTD and TMM, are compared. Then, they shift their attention only to periodic two-dimensional crystals, concentrate on their band properties, and study their unusual refractive behavior. Anomalous refractive phenomena in photonic crystals included cases where the beam refracts on the ''wrong'' side of the surface normal. The latter phenomenon, is known as negative refraction and was previously observed in materials where the wave vector, the electric field, and the magnetic field form a left-handed set of vectors. These materials are generally called left-handed materials (LHM) or negative index materials (NIM). They investigated the possibility that the photonic crystal behaves as a LHM, and how this behavior relates
Propagation of electromagnetic waves in a weak collisional and fully ionized dusty plasma
Energy Technology Data Exchange (ETDEWEB)
Jia, Jieshu; Yuan, Chengxun, E-mail: yuancx@hit.edu.cn; Gao, Ruilin; Wang, Ying; Zhou, Zhong-Xiang [Department of Physics, Harbin Institute of Technology, Harbin 150001 (China); Liu, Sha; Yue, Feng [Shanghai Institute of Spaceflight Control Technology, Shanghai 200233 (China); Wu, Jian [China Research Institute of Radio wave Propagation, Beijing 102206 (China); Li, Hui [Department of Physics, Harbin Institute of Technology, Harbin 150001 (China); China Research Institute of Radio wave Propagation, Beijing 102206 (China)
2016-04-15
The propagation properties of electromagnetic (EM) waves in fully ionized dusty plasmas is the subject of this study. The dielectric relationships for EM waves propagating in a fully ionized dusty plasma was derived from the Boltzmann distribution law, taking into consideration the collision and charging effects of the dust grains. The propagation properties of the EM waves in a dusty plasma were numerically calculated and studied. The study results indicated that the dusty grains with an increased radius and charge were more likely to impede the penetration of EM waves. Dust grains with large radii and high charge cause the attenuation of the EM wave in the dusty plasma. The different density of the dust in the plasma appeared to have no obvious effect on the transmission of the EM waves. The propagation of the EM waves in a weakly ionized dusty plasma varies from that in a fully ionized dusty plasma. The results are helpful to analyze the effects of dust in dusty plasmas and also provide a theoretical basis for future studies.
Propagation of electromagnetic waves in a weak collisional and fully ionized dusty plasma
International Nuclear Information System (INIS)
Jia, Jieshu; Yuan, Chengxun; Gao, Ruilin; Wang, Ying; Zhou, Zhong-Xiang; Liu, Sha; Yue, Feng; Wu, Jian; Li, Hui
2016-01-01
The propagation properties of electromagnetic (EM) waves in fully ionized dusty plasmas is the subject of this study. The dielectric relationships for EM waves propagating in a fully ionized dusty plasma was derived from the Boltzmann distribution law, taking into consideration the collision and charging effects of the dust grains. The propagation properties of the EM waves in a dusty plasma were numerically calculated and studied. The study results indicated that the dusty grains with an increased radius and charge were more likely to impede the penetration of EM waves. Dust grains with large radii and high charge cause the attenuation of the EM wave in the dusty plasma. The different density of the dust in the plasma appeared to have no obvious effect on the transmission of the EM waves. The propagation of the EM waves in a weakly ionized dusty plasma varies from that in a fully ionized dusty plasma. The results are helpful to analyze the effects of dust in dusty plasmas and also provide a theoretical basis for future studies.
The effect of surface wave propagation on neural responses to vibration in primate glabrous skin.
Directory of Open Access Journals (Sweden)
Louise R Manfredi
Full Text Available Because tactile perception relies on the response of large populations of receptors distributed across the skin, we seek to characterize how a mechanical deformation of the skin at one location affects the skin at another. To this end, we introduce a novel non-contact method to characterize the surface waves produced in the skin under a variety of stimulation conditions. Specifically, we deliver vibrations to the fingertip using a vibratory actuator and measure, using a laser Doppler vibrometer, the surface waves at different distances from the locus of stimulation. First, we show that a vibration applied to the fingertip travels at least the length of the finger and that the rate at which it decays is dependent on stimulus frequency. Furthermore, the resonant frequency of the skin matches the frequency at which a subpopulation of afferents, namely Pacinian afferents, is most sensitive. We show that this skin resonance can lead to a two-fold increase in the strength of the response of a simulated afferent population. Second, the rate at which vibrations propagate across the skin is dependent on the stimulus frequency and plateaus at 7 m/s. The resulting delay in neural activation across locations does not substantially blur the temporal patterning in simulated populations of afferents for frequencies less than 200 Hz, which has important implications about how vibratory frequency is encoded in the responses of somatosensory neurons. Third, we show that, despite the dependence of decay rate and propagation speed on frequency, the waveform of a complex vibration is well preserved as it travels across the skin. Our results suggest, then, that the propagation of surface waves promotes the encoding of spectrally complex vibrations as the entire neural population is exposed to essentially the same stimulus. We also discuss the implications of our results for biomechanical models of the skin.
Scattering of electromagnetic wave by the layer with one-dimensional random inhomogeneities
Kogan, Lev; Zaboronkova, Tatiana; Grigoriev, Gennadii., IV.
A great deal of attention has been paid to the study of probability characteristics of electro-magnetic waves scattered by one-dimensional fluctuations of medium dielectric permittivity. However, the problem of a determination of a density of a probability and average intensity of the field inside the stochastically inhomogeneous medium with arbitrary extension of fluc-tuations has not been considered yet. It is the purpose of the present report to find and to analyze the indicated functions for the plane electromagnetic wave scattered by the layer with one-dimensional fluctuations of permittivity. We assumed that the length and the amplitude of individual fluctuations as well the interval between them are random quantities. All of indi-cated fluctuation parameters are supposed as independent random values possessing Gaussian distribution. We considered the stationary time cases both small-scale and large-scale rarefied inhomogeneities. Mathematically such problem can be reduced to the solution of integral Fred-holm equation of second kind for Hertz potential (U). Using the decomposition of the field into the series of multiply scattered waves we obtained the expression for a probability density of the field of the plane wave and determined the moments of the scattered field. We have shown that all odd moments of the centered field (U-¡U¿) are equal to zero and the even moments depend on the intensity. It was obtained that the probability density of the field possesses the Gaussian distribution. The average field is small compared with the standard fluctuation of scattered field for all considered cases of inhomogeneities. The value of average intensity of the field is an order of a standard of fluctuations of field intensity and drops with increases the inhomogeneities length in the case of small-scale inhomogeneities. The behavior of average intensity is more complicated in the case of large-scale medium inhomogeneities. The value of average intensity is the
Yang, Chen
2018-05-01
The transitions from classical theories to quantum theories have attracted many interests. This paper demonstrates the analogy between the electromagnetic potentials and wave-like dynamic variables with their connections to quantum theory for audiences at advanced undergraduate level and above. In the first part, the counterpart relations in the classical electrodynamics (e.g. gauge transform and Lorenz condition) and classical mechanics (e.g. Legendre transform and free particle condition) are presented. These relations lead to similar governing equations of the field variables and dynamic variables. The Lorenz gauge, scalar potential and vector potential manifest a one-to-one similarity to the action, Hamiltonian and momentum, respectively. In the second part, the connections between the classical pictures of electromagnetic field and particle to quantum picture are presented. By characterising the states of electromagnetic field and particle via their (corresponding) variables, their evolution pictures manifest the same algebraic structure (isomorphic). Subsequently, pictures of the electromagnetic field and particle are compared to the quantum picture and their interconnections are given. A brief summary of the obtained results are presented at the end of the paper.
Directory of Open Access Journals (Sweden)
Xiaoxing Zhang
2017-10-01
Full Text Available This study analyzed the transformer electromagnetic gap propagation characteristics. The influence of gap size is also analyzed, and the results experimentally verified. The obtained results indicated that the gap propagation characteristics of electromagnetic wave signals radiated by the partial discharge (PD source in different directions are substantially different. The intensity of the electromagnetic wave in the gap reaches a maximum at a gap height of 1 cm; and inside the gap, the intensity of the electromagnetic wave depicted an increasing trend at the tail area of the gap. Finally, from the obtained results, some suggestions on where to install sensors in practical systems for ultra high frequency (UHF PD signal detection in the transformer gap are provided. The obtained results confirmed the feasibility of using this approach. These results can be seen as a benchmark and a challenge for further research in this field.
International Nuclear Information System (INIS)
Sugaya, Reiji
1989-01-01
General expressions of the matrix elements for nonlinear wave-particle scattering (nonlinear Landau and cyclotron damping) of electromagnetic and electrostatic waves in a homogeneous magnetized plasma are derived from the Vlasov-Maxwell equations. The kinetic wave equations obtained for electromagnetic waves are expressed by four-order tensors in the rotating and cartesian coordinates. No restrictions are imposed on the propagation angle to a uniform magnetic field, the Larmor radius, the frequencies, or the wave numbers. By electrostatic approximation of the dielectric tensor and the matrix elements the kinetic wave equations can be applied to the case in which two scattering waves are electrostatic or they are partially electrostatic. Further, the matrix elements in the limit of parallel or perpendicular propagation to the magnetic field are given. (author)
Electromagnetic wave absorption properties of composites with ultrafine hollow magnetic fibers
Energy Technology Data Exchange (ETDEWEB)
Yi, Jin Woo [Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (BK21 Granted Program), 291 Daehak-ro, Yuseong-gu, Daejeon (Korea, Republic of); Composites Research Center, Korea Institute of Materials Science, 66 Sang-nam-dong, Changwon, Gyeongnam (Korea, Republic of); Lee, Sang Bok; Kim, Jin Bong; Lee, Sang Kwan [Composites Research Center, Korea Institute of Materials Science, 66 Sang-nam-dong, Changwon, Gyeongnam (Korea, Republic of); Park, O Ok, E-mail: oopark@kaist.ac.kr [Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (BK21 Granted Program), 291 Daehak-ro, Yuseong-gu, Daejeon (Korea, Republic of); Department of Energy Systems Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST), 50-1, Sang-ri, Hyeongpung-myeon, Dalseong-gun, Daegu 711-873 (Korea, Republic of)
2014-06-01
Ultrafine hollow magnetic fibers were prepared by electroless plating using hydrolyzed polyester fiber as a sacrificial substrate. These hollow fibers can be served for lightweight and efficient electromagnetic (EM) absorbing materials. As observed from SEM and EDS analysis, hollow structures consisting of Ni inner layer and Fe or Fe–Co outer layer were obtained. By introducing Co onto Fe, oxidation of the Fe layer was successfully prevented making it possible to enhance the complex permeability compared to a case in which only Fe was used. Polymeric composites containing the hollow fibers with different weight fractions and fiber lengths were prepared by a simple mixing process. The electromagnetic wave properties of the composites were measured by a vector network analyzer and it was found that the hollow magnetic fibers show a clear resonance peak of the complex permittivity around the X-band range (8–12 GHz) and the resonance frequency strongly depends on the fiber concentration and length. A possible explanation for the unique resonance is that the hollow fibers possess relatively low electrical conductivity and a long mean free path due to their oxidized phase and hollow structure. The calculated EM wave absorption with the measured EM wave properties showed that the composite containing 30 wt% hollow Ni/Fe–Co (7:3) fibers in length of 180 μm exhibited multiple absorbance peaks resulting in a broad absorption bandwidth of 4.2 GHz. It is obvious that this multiple absorbance is attributed to the resonance characteristic of the composite. - Highlights: • The ultrafine hollow fibers consist of inner Ni layer (∼100 nm) and outer Fe or Fe–Co layer (500–700 nm). • Composites with the fibers show a high permittivity as well as permeability at low weight fractions (10–30 wt%). • The composites show a permittivity resonance and the resonance frequency can be controlled by fiber content and length. • The composite absorber exhibits a double
Ruan, Ping; Yong, Junguang; Shen, Hongtao; Zheng, Xianrong
2012-12-01
Multiple state-of-the-art techniques, such as multi-dimensional micro-imaging, fast multi-channel micro-spetrophotometry, and dynamic micro-imaging analysis, were used to dynamically investigate various effects of cell under the 900 MHz electromagnetic radiation. Cell changes in shape, size, and parameters of Hb absorption spectrum under different power density electromagnetic waves radiation were presented in this article. Experimental results indicated that the isolated human red blood cells (RBCs) do not have obviously real-time responses to the ultra-low density (15 μW/cm(2), 31 μW/cm(2)) electromagnetic wave radiation when the radiation time is not more than 30 min; however, the cells do have significant reactions in shape, size, and the like, to the electromagnetic waves radiation with power densities of 1 mW/cm(2) and 5 mW/cm(2). The data also reveal the possible influences and statistical relationships among living human cell functions, radiation amount, and exposure time with high-frequency electromagnetic waves. The results of this study may be significant on protection of human being and other living organisms against possible radiation affections of the high-frequency electromagnetic waves.
International Nuclear Information System (INIS)
Mazzucato, E.
2002-01-01
Localized measurements of short-scale turbulent fluctuations in tokamaks are still an outstanding problem. In this paper, the method of coherent scattering of electromagnetic waves for the detection of density fluctuations is revisited. Results indicate that the proper choice of frequency, size and launching of the probing wave can transform this method into an excellent technique for high-resolution measurements of those fluctuations that plasma theory indicates as the potential cause of anomalous transport in tokamaks. The best spatial resolution can be achieved when the range of scattering angles corresponding to the spectrum of fluctuations under investigation is small. This favors the use of high frequency probing waves, such as those of far infrared lasers. The application to existing large tokamaks is discussed
Propagation characteristics of electromagnetic waves in dusty plasma with full ionization
Dan, Li; Guo, Li-Xin; Li, Jiang-Ting
2018-01-01
This study investigates the propagation characteristics of electromagnetic (EM) waves in fully ionized dusty plasmas. The propagation characteristics of fully ionized plasma with and without dust under the Fokker-Planck-Landau (FPL) and Bhatnagar-Gross-Krook (BGK) models are compared to those of weakly ionized plasmas by using the propagation matrix method. It is shown that the FPL model is suitable for the analysis of the propagation characteristics of weakly collisional and fully ionized dusty plasmas, as is the BGK model. The influence of varying the dust parameters on the propagation properties of EM waves in the fully ionized dusty plasma was analyzed using the FPL model. The simulation results indicated that the densities and average radii of dust grains influence the reflection and transmission coefficients of fully ionized dusty plasma slabs. These results may be utilized to analyze the effects of interaction between EM waves and dusty plasmas, such as those associated with hypersonic vehicles.
Uncertainty principles for inverse source problems for electromagnetic and elastic waves
Griesmaier, Roland; Sylvester, John
2018-06-01
In isotropic homogeneous media, far fields of time-harmonic electromagnetic waves radiated by compactly supported volume currents, and elastic waves radiated by compactly supported body force densities can be modelled in very similar fashions. Both are projected restricted Fourier transforms of vector-valued source terms. In this work we generalize two types of uncertainty principles recently developed for far fields of scalar-valued time-harmonic waves in Griesmaier and Sylvester (2017 SIAM J. Appl. Math. 77 154–80) to this vector-valued setting. These uncertainty principles yield stability criteria and algorithms for splitting far fields radiated by collections of well-separated sources into the far fields radiated by individual source components, and for the restoration of missing data segments. We discuss proper regularization strategies for these inverse problems, provide stability estimates based on the new uncertainty principles, and comment on reconstruction schemes. A numerical example illustrates our theoretical findings.
Guo, Li-xin; Chen, Wei; Li, Jiang-ting; Ren, Yi; Liu, Song-hua
2018-05-01
The dielectric coefficient of a weakly ionised dusty plasma is used to establish a three-dimensional time and space inhomogeneous dusty plasma sheath. The effects of scattering on electromagnetic (EM) waves in this dusty plasma sheath are investigated using the auxiliary differential equation finite-difference time-domain method. Backward radar cross-sectional values of various parameters, including the dust particle radius, charging frequency of dust particles, dust particle concentration, effective collision frequency, rate of the electron density variation with time, angle of EM wave incidence, and plasma frequency, are analysed within the time and space inhomogeneous plasma sheath. The results show the noticeable effects of dusty plasma parameters on EM waves.
Influence of the electromagnetic parameters on the surface wave attenuation in thin absorbing layers
Li, Yinrui; Li, Dongmeng; Wang, Xian; Nie, Yan; Gong, Rongzhou
2018-05-01
This paper describes the relationships between the surface wave attenuation properties and the electromagnetic parameters of radar absorbing materials (RAMs). In order to conveniently obtain the attenuation constant of TM surface waves over a wide frequency range, the simplified dispersion equations in thin absorbing materials were firstly deduced. The validity of the proposed method was proved by comparing with the classical dispersion equations. Subsequently, the attenuation constants were calculated separately for the absorbing layers with hypothetical relative permittivity and permeability. It is found that the surface wave attenuation properties can be strongly tuned by the permeability of RAM. Meanwhile, the permittivity should be appropriate so as to maintain high cutoff frequency. The present work provides specific methods and designs to improve the attenuation performances of radar absorbing materials.
Phase function of a spherical particle when scattering an inhomogeneous electromagnetic plane wave
DEFF Research Database (Denmark)
Frisvad, Jeppe Revall
2018-01-01
of the complex hypergeometric function 2F1 for every term of a series expansion. In this work, I develop a simpler solution based on associated Legendre functions with argument zero. It is similar to the solution for homogeneous plane waves but with new explicit expressions for the angular dependency of the far......In absorbing media, electromagnetic plane waves are most often inhomogeneous. Existing solutions for the scattering of an inhomogeneous plane wave by a spherical particle provide no explicit expressions for the scattering components. In addition, current analytical solutions require evaluation......-field scattering components, that is, the phase function. I include recurrence formulae for practical evaluation and provide numerical examples to evaluate how well the new expressions match previous work in some limiting cases. The predicted difference in the scattering phase function due to inhomogeneity...
Mitigation of Traffic-Induced Ground Vibration by Inclined Wave Barriers
DEFF Research Database (Denmark)
Andersen, Lars; Augustesen, Anders Hust
2009-01-01
Double sheet pile walls can be used as wave barriers in order to mitigate ground vibrations from railways. The present analysis concerns the efficiency of such barriers, especially with regard to the influence of the barrier inclination and the backfill between the walls. Thus, the screening capa...... of reference following the load. This allows a computation of the steady state response to a harmonically varying point source moving at different speeds typical for a train....
Transition operators in electromagnetic-wave diffraction theory. II - Applications to optics
Hahne, G. E.
1993-01-01
The theory developed by Hahne (1992) for the diffraction of time-harmonic electromagnetic waves from fixed obstacles is briefly summarized and extended. Applications of the theory are considered which comprise, first, a spherical harmonic expansion of the so-called radiation impedance operator in the theory, for a spherical surface, and second, a reconsideration of familiar short-wavelength approximation from the new standpoint, including a derivation of the so-called physical optics method on the basis of quasi-planar approximation to the radiation impedance operator, augmented by the method of stationary phase. The latter includes a rederivation of the geometrical optics approximation for the complete Green's function for the electromagnetic field in the presence of a smooth- and a convex-surfaced perfectly electrically conductive obstacle.
Adrian, Mark L.; Wendel, D. E.
2012-01-01
We investigate observations of intense bursts of electromagnetic wave energy in association with the thin current layers of turbulent magnetosheath reconnection. These observed emissions - typically detected in the layers immediately outside of the current layer proper - form two distinct types: (i) broadband emissions that extend continuously to lOs of Hertz; and (ii) structured bursts of emitted energy that occur above 80-Hz, often displaying features reminiscent of absorption bands and are observed near the local minima in the magnetic field. We present detailed analyses of these intense bursts of electromagnetic energy and quantify their proximity to X-IO-nulls and magnetic spine connected null pairs, as well as their correlation - if any - to the amount of magnetic energy converted by the process of magnetic reconnection.
PECULIARITIES OF THE EFFECTS OF ELECTROMAGNETIC WAVES OF THE VISIBLE RANGE ON LIVING ORGANISMS
Directory of Open Access Journals (Sweden)
S. A. Gulyar
2016-08-01
Full Text Available Our experimental studies and a set of the published data allow one to conclude that animals and humans can perceive visible light not only with mediation of the visual sensory system, but also due to the existence of specific extraocular photoreceptors. In the latter system, we can classify three separate stable levels of interaction with exogeneous electromagnetic waves (EMW of the visible range. The first, most simple level is the cellular level (cells possessing sensor proteins reactable to EMW. The next, higher level is based on interaction of EVW with specialized electromagnetoreceptors; acupuncture points and meridians providing the maintenance of electromagnetic homeostasis of the organism cam be considered such a receptor system. Finally, the most complex level involves specialized sensory pathways and central brain structures controlling general homeostasis of the organism with mediation of the processes of metabolism.
Controlling runaway vortex via externally injected high-frequency electromagnetic waves
Guo, Zehua; McDevitt, Chris; Tang, Xianzhu
2017-10-01
One way of mitigating runaway damage of the plasma-facing components in a tokamak fusion reactor is by limiting the runaway electron energy under a few MeV, while not necessarily reducing the runaway current appreciably. Here we describe a physics mechanism by which such momentum space engineering of the runaway distribution can be facilitated by externally injected high-frequency electromagnetic waves such as the whistler waves. The drastic impact that wave-induced scattering can have on the runaway energy distribution is fundamentally the result of its ability to control the runaway vortex in the momentum space. The runaway vortex, which is a local circulation of runaways in momentum space, is the outcome of the competition between Coulomb collisions, synchrotron radiation damping, and runaway acceleration by parallel electric field. By introducing a wave that resonantly interacts with runaways at a particular range of energy that is mildly relativistic, the enhanced scattering would reshape the vortex by cutting off the part that is highly relativistic. The efficiency of resonant scattering accentuates the requirement that the wave amplitude can be small so the power requirement from external wave injection is practical for the mitigation scheme.
International Nuclear Information System (INIS)
Zhen-Peng, Su; Hui-Nan, Zheng
2009-01-01
The bounce-averaged Fokker–Planck equation is solved to study the relativistic electron phase space density (PSD) evolution in the outer radiation belt due to resonant interactions with plasmaspheric plume electromagnetic ion cyclotron (EMIC) waves. It is found that the PSDs of relativistic electrons can be depleted by 1–3 orders of magnitude in 5h, supporting the previous finding that resonant interactions with EMIC waves may account for the frequently observed relativistic electron flux dropouts in the outer radiation belt during the main phase of a storm. The significant precipitation loss of ∼MeV electrons is primarily induced by the EMIC waves in H + and He + bands. The rapid remove of highly relativistic electrons (> 5 MeV) is mainly driven by the EMIC waves in O + band at lower pitch-angles, as well as the EMIC waves in H + and He + bands at larger pitch-angles. Moreover, a stronger depletion of relativistic electrons is found to occur over a wider pitch angle range when EMIC waves are centering relatively higher in the band
Energy transfer between energetic ring current H(+) and O(+) by electromagnetic ion cyclotron waves
Thorne, Richard M.; Horne, Richard B.
1994-01-01
Electromagnetic ion cyclotron (EMIC) waves in the frequency range below the helium gyrofrequency can be excited in the equatorial region of the outer magnetosphere by cyclotron resonant instability with anisotropic ring current H(+) ions. As the unducted waves propagate to higher latitudes, the wave normal should become highly inclined to the ambient magnetic field. Under such conditions, wave energy can be absorbed by cyclotron resonant interactions with ambient O(+), leading to ion heating perpendicular to the ambient magnetic field. Resonant wave absorption peaks in the vicinity of the bi-ion frequency and the second harmonic of the O(+) gyrofrequrency. This absorption should mainly occur at latitudes between 10 deg and 30 deg along auroral field lines (L is greater than or equal to 7) in the postnoon sector. The concomitant ion heating perpendicular to the ambient magnetic field can contribute to the isotropization and geomagnetic trapping of collapsed O(+) ion conics (or beams) that originate from a low-altitude ionospheric source region. During geomagnetic storms when the O(+) content of the magnetosphere is significantly enhanced, the absorption of EMIC waves should become more efficient, and it may contribute to the observed acceleration of O(+) ions of ionospheric origin up to ring current energies.
Stimulated scattering of electromagnetic waves carrying orbital angular momentum in quantum plasmas.
Shukla, P K; Eliasson, B; Stenflo, L
2012-07-01
We investigate stimulated scattering instabilities of coherent circularly polarized electromagnetic (CPEM) waves carrying orbital angular momentum (OAM) in dense quantum plasmas with degenerate electrons and nondegenerate ions. For this purpose, we employ the coupled equations for the CPEM wave vector potential and the driven (by the ponderomotive force of the CPEM waves) equations for the electron and ion plasma oscillations. The electrons are significantly affected by the quantum forces (viz., the quantum statistical pressure, the quantum Bohm potential, as well as the electron exchange and electron correlations due to electron spin), which are included in the framework of the quantum hydrodynamical description of the electrons. Furthermore, our investigation of the stimulated Brillouin instability of coherent CPEM waves uses the generalized ion momentum equation that includes strong ion coupling effects. The nonlinear equations for the coupled CPEM and quantum plasma waves are then analyzed to obtain nonlinear dispersion relations which exhibit stimulated Raman, stimulated Brillouin, and modulational instabilities of CPEM waves carrying OAM. The present results are useful for understanding the origin of scattered light off low-frequency density fluctuations in high-energy density plasmas where quantum effects are eminent.
International Nuclear Information System (INIS)
Faith, J.; Kuo, S.P.; Huang, J.
1997-01-01
Experimental and numerical results of the interaction of electromagnetic waves with rapidly time varying spatially periodic plasmas are presented. It is shown that a number of Floquet modes, each with their own oscillation frequency, are created during the interaction. Included among these modes are downshifted waves which will not exist in the single slab case, and also waves with a larger upshifted frequency than one can obtain with a single plasma layer of the same density. In addition, the periodic structure is characterized by pass and stop bands that are different from those of a single plasma layer, and the frequencies of the downshifted modes falling in the stop band of a single plasma layer. Therefore these waves are trapped within the plasma structure until the plasma decays away. To show this phenomenon a chamber experiment is conducted, with the periodic plasma being produced by a capacitive discharge. The power spectrum recorded for waves interacting with the plasma shows vastly improved efficiency in the downshift mechanism, which the numerical calculations suggest is related to the trapping of the wave within the plasma. Reproducible results are recorded which are found to agree well with the numerical simulation. copyright 1997 The American Physical Society
International Nuclear Information System (INIS)
Skoblin, A.A.
1994-01-01
Free nonrelativistic electrons in both a static magnetic field and an electromagnetic wave are considered. A plane-polarized wave propagates along a magnetic field, its frequency is close to the electron rotation frequency in a magnetic field. Electron spin is taken into account. An electron quasi energy spectrum and steady states (quasi energy states) are constructed. 6 refs
Directory of Open Access Journals (Sweden)
Armine Amyan
2004-01-01
Full Text Available The changes of wet and dry weights and germination of barley seed in different periods of its swelling in nontreated (control, extremely low frequency electromagnetic fields (ELF EMF treated, and extremely low frequency vibrations (ELFVtreated cold (4°C and warm (20°C distilled water (DW were studied. The metabolic-dependent seed hydration, dry weight dissolving, germination, and water binding in seed were modulated by preliminary EMF- and ELFV-treated DW. Frequency “windows” for the effect of EMF and ELFV on seed hydration, solubility, water binding in seed, and germination were discovered. These “windows” were different for EMF and ELFV, as well as in various phases of seed swelling. It is suggested that EMF-induced water structure modification has a different biological effect on the process of seed hydration, solubility, water binding in seed, and germination compared to ELFV.
Charge symmetry of electron wave functions in a quantized electromagnetic wave field
Energy Technology Data Exchange (ETDEWEB)
Fedorov, M V [AN SSSR, Moscow. Fizicheskij Inst.
1975-01-01
An attempt to clear up the reasons of the electron charge symmetry violation in the quantum wave field was made in this article. For this purpose the connection between the Dirac equation and the electron wave functions in the external field with the exact equation of quantum electrodynamics is established. Attention is paid to the fact that a number of equations for single-electron wave functions can be used in the framework of the same assumptions. It permits the construction of the charge-symmetric solutions in particular.
Torrent, Daniel; Sánchez-Dehesa, José
2009-08-07
We demonstrate that metamaterials with anisotropic properties can be used to develop a new class of periodic structures that has been named radial wave crystals. They can be sonic or photonic, and wave propagation along the radial directions is obtained through Bloch states like in usual sonic or photonic crystals. The band structure of the proposed structures can be tailored in a large amount to get exciting novel wave phenomena. For example, it is shown that acoustical cavities based on radial sonic crystals can be employed as passive devices for beam forming or dynamically orientated antennas for sound localization.
Bowen, LI; Zhibin, WANG; Qiuyue, NIE; Xiaogang, WANG; Fanrong, KONG; Zhenyu, WANG
2018-01-01
Intensive collisions between electrons and neutral particles in partially ionized plasmas generated in atmospheric/sub-atmospheric pressure environments can sufficiently affect the propagation characteristics of electromagnetic waves, particularly in the sub-wavelength regime. To investigate the collisional effect in such plasmas, we introduce a simplified plasma slab model with a thickness on the order of the wavelength of the incident electromagnetic wave. The scattering matrix method (SMM) is applied to solve the wave equation in the plasma slab with significant nonuniformity. Results show that the collisions between the electrons and the neutral particles, as well as the incident angle and the plasma thickness, can disturb the transmission and reduce reflection significantly.
International Nuclear Information System (INIS)
Salimullah, M.; Rahman, M. M.; Zeba, I.; Shah, H. A.; Murtaza, G.; Shukla, P. K.
2006-01-01
The electromagnetic waves below the ion-cyclotron frequency have been examined in a collisionless and homogeneous dusty plasma in the presence of a dust beam parallel to the direction of the external magnetic field. The low-frequency mixed electromagnetic dust-lower-hybrid and purely transverse magnetosonic waves become unstable for the sheared flow of dust grains and grow in amplitude when the drift velocity of the dust grains exceeds the parallel phase velocity of the waves. The growth rate depends dominantly upon the thermal velocity and density of the electrons
Terminal load response law of coaxial cable to continuous wave electromagnetic irradiation
International Nuclear Information System (INIS)
Pan Xiaodong; Wei Guanghui; Li Xinfeng; Lu Xinfu
2012-01-01
In order to study the coupling response law of continuous wave electromagnetic irradiation to coaxial cable, the typical RF coaxial cable is selected as the object under test. The equipment or subsystem connected by coaxial cable is equivalent to a lumped load. Continuous wave irradiation effect experiments under different conditions are carried out to analyze the terminal load response law of coaxial cable. The results indicate that the coaxial cable has a frequency selecting characteristic under electromagnetic irradiation, and the terminal load response voltage peak appears at a series of discrete frequency points where the test cable's relative lengths equal to semi-integers. When the coaxial cable is irradiated by continuous wave, the induced sheath current converts to the differential-mode induced voltage between inner conductor and shielding layer through transfer impedance, and the internal resistance of induced voltage source is the characteristic impedance of the coaxial cable. The change in terminal load value has no influence on the response curve. The voltages on the terminal load and the internal resistance of equivalent induced voltage source obey the principle of voltage division. Moreover, when the sheath current on the coaxial cable is in resonance, the distributed induced voltage between adjacent current nodes is in the same polarity, which can be equivalent to a single induced voltage source. The induced voltage source which is adjacent to the terminal load plays the leading role in the irradiation response process. (authors)
Carcione, José M
2007-01-01
This book examines the differences between an ideal and a real description of wave propagation, where ideal means an elastic (lossless), isotropic and single-phase medium, and real means an anelastic, anisotropic and multi-phase medium. The analysis starts by introducing the relevant stress-strain relation. This relation and the equations of momentum conservation are combined to give the equation of motion. The differential formulation is written in terms of memory variables, and Biot's theory is used to describe wave propagation in porous media. For each rheology, a plane-wave analysis is performed in order to understand the physics of wave propagation. The book contains a review of the main direct numerical methods for solving the equation of motion in the time and space domains. The emphasis is on geophysical applications for seismic exploration, but researchers in the fields of earthquake seismology, rock acoustics, and material science - including many branches of acoustics of fluids and solids - may als...
El Aroudi, Abdelali
2014-05-01
Recently, nonlinearities have been shown to play an important role in increasing the extracted energy of vibration-based energy harvesting systems. In this paper, we study the dynamical behavior of a piecewise linear (PWL) spring-mass-damper system for vibration-based energy harvesting applications. First, we present a continuous time single degree of freedom PWL dynamical model of the system. Different configurations of the PWL model and their corresponding state-space regions are derived. Then, from this PWL model, extensive numerical simulations are carried out by computing time-domain waveforms, state-space trajectories and frequency responses under a deterministic harmonic excitation for different sets of system parameter values. Stability analysis is performed using Floquet theory combined with Filippov method, Poincaré map modeling and finite difference method (FDM). The Floquet multipliers are calculated using these three approaches and a good concordance is obtained among them. The performance of the system in terms of the harvested energy is studied by considering both purely harmonic excitation and a noisy vibrational source. A frequency-domain analysis shows that the harvested energy could be larger at low frequencies as compared to an equivalent linear system, in particular, for relatively low excitation intensities. This could be an advantage for potential use of this system in low frequency ambient vibrational-based energy harvesting applications. © 2014 World Scientific Publishing Company.