WorldWideScience

Sample records for frequency electromagnetic wave

  1. Measurements Of High Frequency Electromagnetic Waves In Center Of Mus

    OpenAIRE

    etem, taha; ABBASOV, Teymuraz

    2016-01-01

    All electrically powered devices cause electromagnetic wave exposure onhuman body and we use them nearly every moment in a day. Mobile phones,computers, televisions, hair dryers, lighting systems, etc. they all useelectricity and naturally radiate electromagnetic waves. Effects ofelectromagnetic waves are not clear but international organizations definelimit values depending on epidemiological studies in this field. In this studywe measure high frequency electromagnetic waves in city center o...

  2. Electromagnetic Waves

    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...

  3. Frequency Domain Modelling of Electromagnetic Wave Propagation in Layered Media

    Science.gov (United States)

    Schmidt, Felix; Lünenschloss, Peter; Mai, Juliane; Wagner, Norman; Töpfer, Hannes; Bumberger, Jan

    2016-04-01

    The amount of water in porous media such as soils and rocks is a key parameter when water resources are under investigation. Especially the quantitative spatial distribution and temporal evolution of water contents in soil formations are needed. In high frequency electromagnetic applications soil water content is quantitatively derived from the propagation behavior of electromagnetic waves along waveguides embedded in soil formations. The spatial distribution of the dielectric material properties along the waveguide can be estimated by numerical solving of the inverse problem based on the full wave forward model in time or frequency domain. However, current approaches mostly neglect or approximate the frequency dependence of the electromagnetic material properties of transfer function of the waveguide. As a first prove of concept a full two port broadband frequency domain forward model for propagation of transverse electromagnetic (TEM) waves in coaxial waveguide has been implemented. It is based on the propagation matrix approach for layered transmission line sections. Depending on the complexity of the material different models for the frequency dependent complex permittivity were applied. For the validation of the model a broadband frequency domain measurement with network analyzer technique was used. The measurement is based on a 20 cm long 50 Ohm 20/46 coaxial transmission line cell considering inhomogeneous material distributions. This approach allows (i) an increase of the waveguide calibration accuracy in comparison to conventional TDR based technique and (ii) the consideration of the broadband permittivity spectrum of the porous material. In order to systematic analyze the model, theoretical results were compared with measurements as well as 3D broadband finite element modeling of homogeneous and layered media in the coaxial transmission line cell. Defined standards (Teflon, dry glass beads, de-ionized water) were placed inside the line as the dielectric

  4. Controlling Energy Radiations of Electromagnetic Waves via Frequency Coding Metamaterials.

    Science.gov (United States)

    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.

  5. Electromagnetic Waves

    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....

  6. 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.

  7. Semiannual Status Report. [excitation of electromagnetic waves in the whistler frequency range

    Science.gov (United States)

    1994-01-01

    During the last six months, we have continued our study of the excitation of electromagnetic waves in the whistler frequency range and the role that these waves will play in the acceleration of electrons and ions in the auroral region. A paper entitled 'Electron Beam Excitation of Upstream Waves in the Whistler Mode Frequency Range' was listed in the Journal of Geophysical Research. In this paper, we have shown that an anisotropic electron beam (or gyrating electron beam) is capable of generating both left-hand and right-hand polarized electromagnetic waves in the whistler frequency range. Since right-hand polarized electromagnetic waves can interact with background electrons and left-hand polarized waves can interact with background ions through cyclotron resonance, it is possible that these beam generated left-hand and right-hand polarized electromagnetic waves can accelerate either ions or electrons (or both), depending on the physical parameters under consideration. We are currently carrying out a comprehensive study of the electromagnetic whistler and lower hybrid like waves observed in the auroral zone using both wave and particle data. Our first task is to identify these wave modes and compare it with particle observations. Using both the DE-1 particle and wave measurements, we can positively identify those electromagnetics lower hybrid like waves as fast magnetosonic waves and the upper cutoff of these waves is the local lower hybrid frequency. From the upper cutoff of the frequency spectrum, one can infer the particle density and the result is in very good agreement with the particle data. Since these electromagnetic lower hybrid like waves can have frequencies extended down to the local ion cyclotron frequency, it practically confirms that they are not whistler waves.

  8. Semiannual Status Report. [excitation of electromagnetic waves in the whistler frequency range

    Science.gov (United States)

    1994-01-01

    During the last six months, we have continued our study of the excitation of electromagnetic waves in the whistler frequency range and the role that these waves will play in the acceleration of electrons and ions in the auroral region. A paper entitled 'Electron Beam Excitation of Upstream Waves in the Whistler Mode Frequency Range' was listed in the Journal of Geophysical Research. In this paper, we have shown that an anisotropic electron beam (or gyrating electron beam) is capable of generating both left-hand and right-hand polarized electromagnetic waves in the whistler frequency range. Since right-hand polarized electromagnetic waves can interact with background electrons and left-hand polarized waves can interact with background ions through cyclotron resonance, it is possible that these beam generated left-hand and right-hand polarized electromagnetic waves can accelerate either ions or electrons (or both), depending on the physical parameters under consideration. We are currently carrying out a comprehensive study of the electromagnetic whistler and lower hybrid like waves observed in the auroral zone using both wave and particle data. Our first task is to identify these wave modes and compare it with particle observations. Using both the DE-1 particle and wave measurements, we can positively identify those electromagnetics lower hybrid like waves as fast magnetosonic waves and the upper cutoff of these waves is the local lower hybrid frequency. From the upper cutoff of the frequency spectrum, one can infer the particle density and the result is in very good agreement with the particle data. Since these electromagnetic lower hybrid like waves can have frequencies extended down to the local ion cyclotron frequency, it practically confirms that they are not whistler waves.

  9. Frequency-domain electromagnetic sounding with combination wave in near-field zone

    Institute of Scientific and Technical Information of China (English)

    苏发; 何继善

    1996-01-01

    By analysing the propagation law of electromagnetic wave,the distribution pattern of the field and the theory of frequency electromagnetic sounding,the physical mechanisms that make the frequency electromagnetic sounding in near-field zone difficult are discussed.Based on the theory of near source field,a new method of dual-frequency electromagnetic sounding of combination wave in near-field zone is advanced.Meanwhile,the method of measurement of fields,the definition of apparent resistivity and the numerical algorithm are approached.

  10. The numerical simulation on electromagnetic wave attenuation characteristics of coal face in time-frequency domain

    Institute of Scientific and Technical Information of China (English)

    YU Shi-jian; Cheng Jiu-long; LIU Jia-qi

    2007-01-01

    This paper took the abnormal geological objects with high or low resistivity in the coal face as the background to establish the physical model. 2D forward numerical simulation for electromagnetic wave equation was implemented by the finite-difference scheme. According to the simulative results, the attenuation-absorption coefficient were calculated respectively based on field intensity and frequency shift parameter. Research result indicates, when coal-bed contains high electric resistivity geological abnormal object or low electric resistivity geological abnormal object, absorption attenuation function researched by frequency shift parameter of electromagnetic wave signal is more sensitive than by electromagnetic field intensity parameter.

  11. Simulation Study of the Relationship between Partial Discharge and Ultrahigh-Frequency Electromagnetic Wave in GIS

    Directory of Open Access Journals (Sweden)

    Wang Jiang

    2014-03-01

    Full Text Available When partial discharge occurs in Gas Insulated Switchgear (GIS with insulation defects, Ultrahigh-Frequency (UHF electromagnetic wave up to several MHz and GHz will be exited and propagate inside GIS cavity. This study, based on the propagation theory of electromagnetic waves in coaxial waveguide, performs simulation analysis of the relationship between PD pulse form and the exited UHF electromagnetic wave using Finite-Deferential Time-Domain (FDTD algorithm. First, we study the relationship of partial discharge magnitude and electric field strength of electromagnetic wave. It is found that the changes of partial discharge magnitude have little effect on electric field strength of electromagnetic wave at certain variation rate of PD pulse current. Next, we examine the relationship of variation rate of PD pulse current to electric field strength of electromagnetic wave. It is pointed out that, at a certain partial discharge magnitude, the two are approximately linearly related. Finally, we study the impact of variation rate of PD pulse current on higher mode components. Variation coefficient is used to analyze the proportion of higher mode components in electromagnetic wave. The proportion of higher mode components increases with increasing variation rate of PD pulse current.

  12. Electromagnetic Waves with Frequencies Near the Local Proton Gryofrequency: ISEF-3 1 AU Observations

    Science.gov (United States)

    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.

  13. Electromagnetic Waves with Frequencies Near the Local Proton Gryofrequency: ISEF-3 1 AU Observations

    Science.gov (United States)

    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.

  14. 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.

  15. Unprecedentedly strong and narrow electromagnetic emissions stimulated by high-frequency radio waves in the ionosphere.

    Science.gov (United States)

    Norin, L; Leyser, T B; Nordblad, E; Thidé, B; McCarrick, M

    2009-02-13

    Experimental results of secondary electromagnetic radiation, stimulated by high-frequency radio waves irradiating the ionosphere, are reported. We have observed emission peaks, shifted in frequency up to a few tens of Hertz from radio waves transmitted at several megahertz. These emission peaks are by far the strongest spectral features of secondary radiation that have been reported. The emissions are attributed to stimulated Brillouin scattering, long predicted but hitherto never unambiguously identified in high-frequency ionospheric interaction experiments. The experiments were performed at the High-Frequency Active Auroral Research Program (HAARP), Alaska, USA.

  16. Electromagnetic waves near the proton cyclotron frequency in the solar wind

    Science.gov (United States)

    Jian, Lan; Alexander, Robert; Wicks, Robert; Stevens, Michael; Figueroa-Vinas, Adolfo; Russell, Christopher

    2015-04-01

    Strong narrow-band electromagnetic waves around the proton cyclotron frequency have been found sporadically in the solar wind throughout the inner heliosphere. They are nearly-circularly polarized and propagate close to the magnetic field. Electromagnetic waves near the proton cyclotron frequency can be ion cyclotron waves or magnetosonic waves. They can play an important role in modulating the solar wind ion distribution, and contribute to the heating and acceleration of solar wind. Since the waves are left-hand or right-hand polarized in the spacecraft frame with similar characteristics, they are probably due to Doppler shift of a same type of waves, or there could be a mixture of waves with intrinsically different polarizations. Through the assistance of audification, we have studied the long-lasting low frequency wave events in 2005 using high-cadence magnetic field data from the Wind mission. The Solar Wind Experiment team of the Wind mission has provided the temperature anisotropies for core protons, beam protons, and alpha particles, as well as the beam drift for selected cases. We conduct wave dispersion analysis using these ion moments to examine if these waves can be explained by ion cyclotron anisotropy instability or ion beam instability related to the solar wind inhomogeneities.

  17. A Review of Low Frequency Electromagnetic Wave Phenomena Related to Tropospheric-Ionospheric Coupling Mechanisms

    Science.gov (United States)

    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.

  18. Analysis of Excitation Characteristics of Ultra High Frequency Electromagnetic Waves Induced by PD in GIS

    Institute of Scientific and Technical Information of China (English)

    DING Dengwei; GAO Wensheng; YAO Senjing; LIU Weidong; HE Jiaxi

    2013-01-01

    The understanding of the excitation mechanism of ultra high frequency (UHF) electromagnetic waves (EW) is essential for applying UHF method to partial discharge (PD) detection.Since the EW induced by PD in gas insulated switchgear (GIS) contains not only transverse electromagnetic (TEM) wave,but also high-order transverse electric (TE) and high-order transverse magnetic (TM) waves,we analyzed the proportions between the TEM wave and the high order waves,as well as the influence of the PD position on this proportion,using the finite different time domain (FDTD) method.According to the unique characteristics of the waves,they are separated only approximately.It is found that the high-order mode is the main component,more than 70%,of the electric field around the enclosure of GIS,and that with the increasing distance between PD source and inner conductors,the low frequency (below about 800 MHz) component of EW decreases,but the high frequency component (above 1 GHz) increases,meanwhile the proportion of high-order components in EW could reach 77% from 70%.It concluded that the closer the PD source to the enclosure is,the easier high order EW may be excited.

  19. Full wave computation of electromagnetic wave excitation, propagation, and absorption at the ion cyclotron frequency in fusion experiments

    Energy Technology Data Exchange (ETDEWEB)

    Batchelor, D.B.; Jaeger, E.F.

    1990-01-01

    High-power electromagnetic waves at frequencies ranging from a few megahertz to a few hundred gigahertz serve many important functions in modern fusion experiments. Probably the most important application is plasma heating. Ignition of a fusion reactor will require a plasma to be heated until the average particle energy is {approximately}10 keV (temperature > 10{sup 8} K). This is routinely accomplished in existing large devices. Waves at the ion cyclotron frequency (typically f = 30 to 100 MHz) are very important for fusion devices because of low cost/unit power compared to other frequency regimes and because of their ability to directly heat fusile ions. These waves are also useful for modifying the velocity distribution for improved stability and to drive currents which affect plasma equilibrium. Study of this frequency range is, however, greatly complicated by long wavelengths compared to device size, nonsymmetric device geometry, and the tendency of the waves to linearly transform to shorter wavelength modes. Geometrical optics is generally inapplicable. Thus, codes have been developed to solve the vector wave equation in toroidal geometry for hot plasmas having anisotropic, spatially nonuniform, dispersive constitutive relations. In this paper we describe the code ORION developed at Oak Ridge National Laboratory and present illustrative applications to a range of fusion experiments. Specific applications of the code include detailed modeling of the antennas used to launch the waves, calculation of wave propagation throughout the plasma, and modeling of the absorption of the waves by the plasma. 11 refs., 3 figs.

  20. Stacked Polypyrrole-Coated Nonwoven Fabric Sheets for Absorbing Electromagnetic Waves with Broadband Frequencies

    Science.gov (United States)

    Egami, Yoshihiro; Yamamoto, Takashi; Suzuki, Kunio; Higuchi, Eiji; Inoue, Hiroshi

    2012-08-01

    Microwave absorbability of electromagnetic waves in the frequency range of 1-15 GHz, which is often used in recent wireless applications, for stacks of various numbers of conductive nonwoven fabric sheets with different resistivity was evaluated to clarify their possibility as the broadband microwave absorber in the frequency range of 1-15 GHz. The conductive nonwoven fabric sheets coated with polypyrrole nanoparticles, which had resistivities from 4.6 ×103 to 1.2×102 Ω cm, were prepared by immersing nonwoven fabric sheets in solutions containing various concentrations of an oxidizing agent and a dopant and then exposing the sheets to pyrrole vapor. The real part (ɛ') and the imaginary part (ɛ'') of complex permittivity for each conductive nonwoven fabric sheet increased with decreasing frequency, indicating the dispersion of permittivity. In addition, the reflection loss decreased when ammonium persulfate concentration increased and/or the stack size increased. However, the stack of two conductive nonwoven fabric sheets (thickness: 6.6 mm) with a resistivity of less than 120 Ω cm had average reflection losses of less than -10 dB in the frequency range of 1-15 GHz. From this way, it can be considered that the stacked conductive nonwoven fabric sheets prepared in this study can be a new material that effectively absorbs electromagnetic waves in the wide frequency range.

  1. Computational modeling of a single microdischarge and its interactions with high frequency electromagnetic waves

    Science.gov (United States)

    PanneerChelvam, Premkumar; Raja, Laxminarayan L.; Upadhyay, Rochan R.

    2016-09-01

    We discuss the computational modeling of a single microplasma and its interaction with high frequency electromagnetic waves in a microwave regime. The work is motivated by a strong recent interest in the area of reconfigurable plasma-based metamaterials (MM) and photonic crystals (PC) where the interaction of electromagnetic waves with plasma elements (e.g. microdischarges) forms the basis for the MM/PC operation. In this work the microplasma is assumed to be driven by a 1 GHz microwave source in a parallel plate electrode configuration. Its structure and properties are described using a fluid plasma model. The interaction of the microplasma with a 100 GHz transverse magnetic (TM) and transverse electric (TE) polarized microwave propagating in a rectangular waveguide is studied. Two operational regimes of the plasma discharge are considered. One in which the peak electron density is less than the critical density (under-dense) for the interacting wave and the other in which it is higher (over-dense). The under-dense plasma with positive less than unity dielectric constant has sufficient dielectric contrast from the surrounding medium that a slight perturbation of the incident wave and bending of wave path lines through the discharge is realized. The over-dense plasma interacts strongly with the TM polarized wave because of epsilon-zero resonance at the critical density locations and the wave path lines are observed to reverse their direction near the regions of critical plasma density. The transverse electric (TE) polarized wave does not exhibit epsilon-zero resonance and the interactions are weaker than the TM wave.

  2. Computer-aided design-based high-frequency electromagnetic wave scattering from complex bodies

    Science.gov (United States)

    Baldauf, John Eric

    1991-02-01

    This work investigates the use of high frequency electromagnetic scattering techniques, such as the physical theory of diffraction (PTD) and the geometrical theory of diffraction (GTD) and the shooting and bouncing rays (SBR) method combined with computer aided design (CAD) compatible geometries, to perform the electromagnetic scattering analysis of complex arbitrary bodies. The use of CAD formats such as solid modelled bodies and bodies modelled with triangular patch surface elements allows the scattering analysis of arbitrary bodies which can be constructed using CAD packages. The scattering analyses are applied to radar cross section (RCS) problems, cavity radiation problems, and antenna pattern predictions of complex electrically large structures, thereby showing that it is feasible to accurately approximate the electromagnetic wave scattering from general complex bodies using CAD techniques and high frequency scattering techniques. First, the RCS of large targets which involve multiple geometric optics (GO) interactions are investigated by comparing the RCS calculated using CAD designed radar targets and the SBR method and PTD for targets such as trihedral corner reflectors and an idealized military vehicle model with the experimentally obtained RCS. The comparisons between the calculated and measured results demonstrate that the SBR and PTD can provide accurate approximations of the RCS for targets which have complex multiple GO interactions. Second, the problem of interior cavity radiation for closed cavities is approached using a ray tracing and GO method based on the SBR method and triangular surface patch described geometries. Comparisons between the ray-based calculations and more exact techniques such as the method of moments (MM) for two-dimensional cavities demonstrate that ray-based methods can provide good approximations for the field behavior inside of nonresonant cavities. A three-dimensional case is shown to demonstrate that this technique can be

  3. Electromagnetic waves with frequencies near the local proton gyrofrequency: ISEE-3 1 AU observations

    Science.gov (United States)

    Tsurutani, Bruce T.; Arballo, John K.; Mok, John; Smith, Edward J.; Mason, Glenn M.; Tan, Lun C.

    1994-01-01

    Low Frequency (LF) electromagnetic waves with periods near the local proton gyrofrequency have been detected in interplanetary space by the magnetometer onboard International-Sun-Earth-Explorer-3 (ISEE-3). Transverse peak-to-peak amplitudes as large as delta vector B/absolute value of B approximately 0.4 have been noted with compressional components (Delta absolute value of B/absolute value of B) typically less than or = 0.1. Generally, the waves have even smaller amplitudes, or are not detectable within the solar wind turbulence. The waves are elliptically/linearly polarized and are often, but not always, found to propagate nearly along vector B(sub zero). Both right- and left-hand polarizations in the spacecraft-frame have been detected. The waves are observed during all orientations of the interplanetary magnetic field, with the Parker spiral orientation being the most common case. Because the waves are detected at and near the local proton cyclotron frequency, the generation mechanism must almost certainly be solar wind pickup of freshly created hydrogen ions. Possible sources for the hydrogen are the Earth's atmosphere, coronal mass ejections from the Sun, comets and interstellar neutral atoms. At this time it is not obvious which potential source is the correct one. Statistical tests employing over one year of ISEE-3 data will be done in the near future to eliminate/confirm some of these possibilities.

  4. Electromagnetic waves with frequencies near the local proton gyrofrequency: ISEE-3 1 AU observations

    Science.gov (United States)

    Tsurutani, Bruce T.; Arballo, John K.; Mok, John; Smith, Edward J.; Mason, Glenn M.; Tan, Lun C.

    1994-01-01

    Low Frequency (LF) electromagnetic waves with periods near the local proton gyrofrequency have been detected in interplanetary space by the magnetometer onboard International-Sun-Earth-Explorer-3 (ISEE-3). Transverse peak-to-peak amplitudes as large as delta vector B/absolute value of B approximately 0.4 have been noted with compressional components (Delta absolute value of B/absolute value of B) typically less than or = 0.1. Generally, the waves have even smaller amplitudes, or are not detectable within the solar wind turbulence. The waves are elliptically/linearly polarized and are often, but not always, found to propagate nearly along vector B(sub zero). Both right- and left-hand polarizations in the spacecraft-frame have been detected. The waves are observed during all orientations of the interplanetary magnetic field, with the Parker spiral orientation being the most common case. Because the waves are detected at and near the local proton cyclotron frequency, the generation mechanism must almost certainly be solar wind pickup of freshly created hydrogen ions. Possible sources for the hydrogen are the Earth's atmosphere, coronal mass ejections from the Sun, comets and interstellar neutral atoms. At this time it is not obvious which potential source is the correct one. Statistical tests employing over one year of ISEE-3 data will be done in the near future to eliminate/confirm some of these possibilities.

  5. Utilization of Electromagnetic Detector for Selection and Detection of High-Frequency Relic Gravitational Waves

    Institute of Scientific and Technical Information of China (English)

    LI Fang-Yu; CHEN Zhen-Ya; YI Ying

    2005-01-01

    @@ It is shown that the coupling system between fractal membranes and a Gaussian beam passing through a static magnetic field has strong selection capability for the stochastic relic gravitational wave (GW) background. The relic G W components propagating along the positive direction of the symmetrical axis of the Gaussian beam might generate an optimal electromagnetic perturbation, while the perturbation produced by the relic GW components propagating along the negative and perpendicular directions to the symmetrical axis will be much less than the former, and the influence of the random fluctuation of the relic GWs to such effect can be neglected. The high-frequency relic GWs satisfying the parameters requirement (h ~ 10-31 or larger), frequency resonance and "direction coupling", in principle, would be selectable and measurable in seconds.

  6. Power Absorption of High Frequency Electromagnetic Waves in a Partially Ionized Plasma Layer in Atmosphere Conditions

    Institute of Scientific and Technical Information of China (English)

    郭斌; 王晓钢

    2005-01-01

    We have studied the absorption, reflection, and transmission of electromagnetic waves in an unmagnetized uniform plasma layer covering a metal surface in atmosphere conditions.Instead of the absorption of the electromagnetic wave propagating only once in previous work on the plasma layer, a general formula of total power absorption by the plasma layer with an infinite time of reflections between the atmosphere-plasma interface and the metal surface has been derived for the first time. Effects of plasma parameters, especially the dependence of the fraction of positive ions, negative ions and electrons in plasmas on the power absorption processes are discussed. The results show that the existence of negative ions significantly reduces the power absorption of the electromagnetic wave. Absorptions of electromagnetic waves are calculated.

  7. Inhibition of Salmonella typhi growth using extremely low frequency electromagnetic (ELF-EM) waves at resonance frequency.

    Science.gov (United States)

    Fadel, M A; Mohamed, S A; Abdelbacki, A M; El-Sharkawy, A H

    2014-08-01

    Typhoid is a serious disease difficult to be treated with conventional drugs. The aim of this study was to demonstrate a new method for the control of Salmonella typhi growth, through the interference with the bioelectric signals generated from the microbe during cell division by extremely low frequency electromagnetic waves (ELF-EMW-ELF-EM) at resonance frequency. Isolated Salmonella typhi was subjected to square amplitude modulated waves (QAMW) with different modulation frequencies from two generators with constant carrier frequency of 10 MHz, amplitude of 10 Vpp, modulating depth ± 2 Vpp and constant field strength of 200 V m(-1) at 37°C. Both the control and exposed samples were incubated at the same conditions during the experiment. The results showed that there was highly significant inhibition effect for Salm. typhi exposed to 0·8 Hz QAMW for a single exposure for 75 min. Dielectric relaxation, TEM and DNA results indicated highly significant changes in the molecular structure of the DNA and cellular membrane resulting from the exposure to the inhibiting EM waves. It was concluded that finding out the inhibiting resonance frequency of ELF-EM waves that deteriorates Salm. typhi growth will be promising method for the treatment of Salm. typhi infection either in vivo or in vitro. This new non-invasive technique for treatment of bacterial infections is of considerable interest for the use in medical and biotechnological applications. © 2014 The Society for Applied Microbiology.

  8. Electromagnetic Response of High-Frequency Gravitational Waves by Coupling Open Resonant Cavity

    Institute of Scientific and Technical Information of China (English)

    LI Fang-Yu; CHEN Ying; WANG Ping

    2007-01-01

    We present a new detecting scheme of high-frequency gravitational waves(HFGWs) in the GHz band,the scheme consists of a high-quality-factor open microwave cavity,a static magnetic field passing through the cavity and an electromagnetic (EM)normal mode stored in the cavity.It is found that under the resonant condition firstand second-order perturbation EM effects have almost the same detecting sensitivity to the HFGWs in the GHz band (h~10-26,v~5GHz),but the former contains more information from the HFGWs.We akso provide a very brief review for possible improving way of the sensitivity.This scheme would be Highly complementary to other schemes of detecting the HFGWs.

  9. Electromagnetic ultrasonic guided waves

    CERN Document Server

    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.

  10. Static electromagnetic frequency changers

    CERN Document Server

    Rozhanskii, L L

    1963-01-01

    Static Electromagnetic Frequency Changers is about the theory, design, construction, and applications of static electromagnetic frequency changers, devices that used for multiplication or division of alternating current frequency. It is originally published in the Russian language. This book is organized into five chapters. The first three chapters introduce the readers to the principles of operation, the construction, and the potential applications of static electromagnetic frequency changers and to the principles of their design. The two concluding chapters use some hitherto unpublished work

  11. Effect of radio frequency waves of electromagnetic field on the tubulin.

    Science.gov (United States)

    Taghi, Mousavi; Gholamhosein, Riazi; Saeed, Rezayi-Zarchi

    2013-09-01

    Microtubules (MTs) are macromolecular structures consisting of tubulin heterodimers and present in almost every eukaryotic cell. MTs fulfill all conditions for generation of electromagnetic field and are electrically polar due to the electrical polarity of a tubulin heterodimer. The calculated static electric dipole moment of about 1000 Debye makes them capable of being aligned parallel to the applied electromagnetic field direction. In the present study, the tubulin heterodimers were extracted and purified from the rat brains. MTs were obtained by polymerization in vitro. Samples of microtubules were adsorbed in the absence and in the presence of electromagnetic fields with radio frequency of 900 Hz. Our results demonstrate the effect of electromagnetic field with 900 Hz frequency to change the structure of MTs. In this paper, a related patent was used that will help to better understand the studied subject.

  12. Electromagnetic waves and photons

    CERN Document Server

    Hofmann, Ralf

    2015-01-01

    We explore how the thermal ground states of two mixing and pure SU(2) Yang-Mills theories, SU(2)$_{\\tiny\\mbox{CMB}}$ of scale $\\Lambda_{\\tiny\\mbox{CMB}}\\sim 10^{-4}\\,$eV and SU(2)$_{e}$ of scale $\\Lambda_{e}\\sim 5\\times 10^5\\,$eV, associate either wave or particle aspects to electromagnetic disturbances during thermalisation towards the photon gas of a blackbody, in realising the photoelectric effect, and through the frequency dependence of the monochromatic, nonthermal beam structure in Thomson/Compton scattering.

  13. Detection and Characterization of Flaws in Sprayed on Foam Insulation with Pulsed Terahertz Frequency Electromagnetic Waves

    Science.gov (United States)

    Winfree, William P.; Madaras, Eric I.

    2005-01-01

    The detection and repair of flaws such as voids and delaminations in the sprayed on foam insulation of the external tank reduces the probability of foam debris during shuttle ascent. The low density of sprayed on foam insulation along with it other physical properties makes detection of flaws difficult with conventional techniques. An emerging technology that has application for quantitative evaluation of flaws in the foam is pulsed electromagnetic waves at terahertz frequencies. The short wavelengths of these terahertz pulses make them ideal for imaging flaws in the foam. This paper examines the application of terahertz pulses for flaw detection in foam characteristic of the foam insulation of the external tank. Of particular interest is the detection of voids and delaminations, encapsulated in the foam or at the interface between the foam and a metal backing. The technique is shown to be capable of imaging small voids and delaminations through as much as 20 cm of foam. Methods for reducing the temporal responses of the terahertz pulses to improve flaw detection and yield quantitative characterizations of the size and location of the flaws are discussed.

  14. Waves of change: immunomodulation of the innate immune response by low frequency electromagnetic field exposure

    NARCIS (Netherlands)

    Golbach, L.A.

    2015-01-01

      In this thesis we investigated possible modulatory roles of low frequency electromagnetic fields (LF EMFs) exposure on the innate immune system. Recent decades have seen a huge increase in the use of electronic devices that nowadays enable us to communicate with distant family, enjoy music ev

  15. Interaction of the Electromagnetic p-Wave with Thin Metal Film in the Field of Resonant Frequencies

    CERN Document Server

    Latyshev, A V

    2011-01-01

    It is shown that for thin metallic films thickness of which does not exceed thickness of skin layer, the problem allows analytical solution. In the field of resonant frequencies the analysis of dependence of coefficients of transmission, reflection and absorbtion on an electromagnetic wave is carried out. Dependence on pitch angle, thickness of the layer and coefficient of specular reflection and on effective electron collision frequency is carried out. The formula for contactless determination (calculation) of a thickness of a film by observable resonant frequencies is deduced.

  16. High frequency electromagnetic dosimetry

    CERN Document Server

    Sánchez-Hernández, David A

    2009-01-01

    Along with the growth of RF and microwave technology applications, there is a mounting concern about the possible adverse effects over human health from electromagnetic radiation. Addressing this issue and putting it into perspective, this groundbreaking resource provides critical details on the latest advances in high frequency electromagnetic dosimetry.

  17. The Study of the Status of Electromagnetic Waves Resulting from BTS (Base Transceiver Station, 900 Megahertz Frequency in Tehran

    Directory of Open Access Journals (Sweden)

    R Hematjo

    2011-10-01

    Full Text Available Background and Objectives: with the developments of technology, contact with various frequencies of electromagnetic fields ( EMF has significantly increased, while the abundant benefits of using microwaves in routine life cannot be neglected. During recent years there have been reports of adverse effects caused by contact with electric and magnetic fields of these waves that spread from BTS antennas. The purpose of this study is the measurement of microwaves spreading around BTS antennas in Tehran.Materials and Methods:  according to the location of BTS antennas in Tehran , power density of electromagnetic waves around 63 antennas in near and distant fields in different distances was measured. The measurements were performed using the standard method of IEEE Std C95.1 by Hi-4333 device .in order to analysis data we used spss 16 and descriptive and deductive statistical tests.Results: results of this study show that in the near field, with increase of distance from the foot of antenna , the average power density of electromagnetic waves increase in a way that in the distance of 10 meters from the antenna foot , the increase of average power density is hardly conceivable and from 10 to 15 meters distance is perfectly noticeable. But in the distant field, with increase of distance from 20 meters, the average power density of the electromagnetic waves decreases; and from 100 meter and further, the gradient of the diagram will get almost linear and the rate of power density reaches the base limit in a way that with the increase of distance there would be no significant decrease.Conclusion: All the measures of power density of electromagnetic waves caused by BTSs are about 0.06% of recommended measures of environmental standards and 0.0000013% of occupational standards. The results of this study are close to the results of other studies.

  18. Calculation of the plasma frequency of a stack of coupled Josephson junctions irradiated with electromagnetic waves

    Science.gov (United States)

    Shukrinov, Yu. M.; Rahmonov, I. R.; Gaafar, M. A.

    2012-11-01

    We perform a precise numerical study of phase dynamics in high-temperature superconductors under electromagnetic radiation. We observe the charging of superconducting layers in the bias current interval corresponding to the Shapiro step. A remarkable change in the longitudinal plasma wavelength at parametric resonance is shown. Double resonance of the Josephson oscillations with radiation and plasma frequencies leads to additional parametric resonances and the non-Bessel Shapiro step.

  19. Frequency sweep rates of rising tone electromagnetic ion cyclotron waves: Comparison between nonlinear theory and Cluster observation

    Energy Technology Data Exchange (ETDEWEB)

    He, Zhaoguo [Center for Space Science and Applied Research, Chinese Academy of Sciences, Beijing 100190 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Zong, Qiugang, E-mail: qgzong@gmail.com; Wang, Yongfu [Institute of Space Physics and Applied Technology, Peking University, Beijing 100871 (China); Liu, Siqing; Lin, Ruilin; Shi, Liqin [Center for Space Science and Applied Research, Chinese Academy of Sciences, Beijing 100190 (China)

    2014-12-15

    Resonant pitch angle scattering by electromagnetic ion cyclotron (EMIC) waves has been suggested to account for the rapid loss of ring current ions and radiation belt electrons. For the rising tone EMIC wave (classified as triggered EMIC emission), its frequency sweep rate strongly affects the efficiency of pitch-angle scattering. Based on the Cluster observations, we analyze three typical cases of rising tone EMIC waves. Two cases locate at the nightside (22.3 and 22.6 magnetic local time (MLT)) equatorial region and one case locates at the duskside (18MLT) higher magnetic latitude (λ = –9.3°) region. For the three cases, the time-dependent wave amplitude, cold electron density, and cold ion density ratio are derived from satellite data; while the ambient magnetic field, thermal proton perpendicular temperature, and the wave spectral can be directly provided by observation. These parameters are input into the nonlinear wave growth model to simulate the time-frequency evolutions of the rising tones. The simulated results show good agreements with the observations of the rising tones, providing further support for the previous finding that the rising tone EMIC wave is excited through the nonlinear wave growth process.

  20. Frequency sweep rates of rising tone electromagnetic ion cyclotron waves: Comparison between nonlinear theory and Cluster observation

    Science.gov (United States)

    He, Zhaoguo; Zong, Qiugang; Liu, Siqing; Wang, Yongfu; Lin, Ruilin; Shi, Liqin

    2014-12-01

    Resonant pitch angle scattering by electromagnetic ion cyclotron (EMIC) waves has been suggested to account for the rapid loss of ring current ions and radiation belt electrons. For the rising tone EMIC wave (classified as triggered EMIC emission), its frequency sweep rate strongly affects the efficiency of pitch-angle scattering. Based on the Cluster observations, we analyze three typical cases of rising tone EMIC waves. Two cases locate at the nightside (22.3 and 22.6 magnetic local time (MLT)) equatorial region and one case locates at the duskside (18MLT) higher magnetic latitude (λ = -9.3°) region. For the three cases, the time-dependent wave amplitude, cold electron density, and cold ion density ratio are derived from satellite data; while the ambient magnetic field, thermal proton perpendicular temperature, and the wave spectral can be directly provided by observation. These parameters are input into the nonlinear wave growth model to simulate the time-frequency evolutions of the rising tones. The simulated results show good agreements with the observations of the rising tones, providing further support for the previous finding that the rising tone EMIC wave is excited through the nonlinear wave growth process.

  1. The propagation characteristics of electromagnetic waves through plasma in the near-field region of low-frequency loop antenna

    Energy Technology Data Exchange (ETDEWEB)

    Liu, DongLin, E-mail: donglinliu@stu.xidian.edu.cn; Li, XiaoPing; Xie, Kai; Liu, ZhiWei [School of Aerospace Science and Technology, Xidian University, Xi' an 710071 (China)

    2015-10-15

    A high-speed vehicle flying through the atmosphere between 100 and 20 km may suffer from a “communication blackout.” In this paper, a low frequency system with an on-board loop antenna to receive signals is presented as a potential blackout mitigation method. Because the plasma sheath is in the near-field region of the loop antenna, the traditional scattering matrix method that is developed for the far-field region may overestimate the electromagnetic (EM) wave's attenuation. To estimate the EM wave's attenuation in the near-field region, EM interference (EMI) shielding theory is introduced. Experiments are conducted, and the results verify the EMI shielding theory's effectiveness. Simulations are also conducted with different plasma parameters, and the results obtained show that the EM wave's attenuation in the near-field region is far below than that in the far-field region. The EM wave's attenuation increases with the increase in electron density and decreases with the increase in collision frequency. The higher the frequency, the larger is the EM wave's attenuation. During the entire re-entry phase of a RAM-C module, the EM wave's attenuations are below 10 dB for EM waves with a frequency of 1 MHz and below 1 dB for EM waves with a frequency of 100 kHz. Therefore, the low frequency systems (e.g., Loran-C) may provide a way to transmit some key information to high-speed vehicles even during the communication “blackout” period.

  2. Solitary Waves in Relativistic Electromagnetic Plasma

    Institute of Scientific and Technical Information of China (English)

    XIE Bai-Song; HUA Cun-Cai

    2005-01-01

    Solitary waves in relativistic electromagnetic plasmas are obtained numerically. The longitudinal momentum of electrons has been taken into account in the problem. It is found that in the moving frame with electromagnetic field propagating the solitary waves can exist in both cases, where the vector potential frequency is larger or smaller than the plasma characteristic frequency.

  3. High frequency electromagnetic tomography

    Energy Technology Data Exchange (ETDEWEB)

    Daily, W.; Ramirez, A.; Ueng, T.; Latorre, R.

    1989-09-01

    An experiment was conducted in G Tunnel at the Nevada Test Site to evaluate high frequency electromagnetic tomography as a candidate for in situ monitoring of hydrology in the near field of a heater placed in densely welded tuff. Tomographs of 200 MHz electromagnetic permittivity were made for several planes between boreholes. Data were taken before the heater was turned on, during heating and during cooldown of the rockmass. This data is interpreted to yield maps of changes in water content of the rockmass as a function of time. This interpretation is based on laboratory measurement of electromagnetic permittivity as a function of water content for densely welded tuff. 8 refs., 6 figs.

  4. Landau levels for electromagnetic wave

    CERN Document Server

    Zyuzin, Vladimir A

    2016-01-01

    In this paper we show that the frequencies of propagating electromagnetic wave (photon) in rotating dielectric media obey Landau quantization. We show that the degeneracy of right and left helicities of photons is broken on the lowest Landau level. In spatially homogeneous system this level is shown to be helical, i.e. left and right helical photons counter-propagate.

  5. Lower hybrid frequency range waves generated by ion polarization drift due to electromagnetic ion cyclotron waves: Analysis of an event observed by the Van Allen Probe B

    Science.gov (United States)

    Khazanov, G. V.; Boardsen, S.; Krivorutsky, E. N.; Engebretson, M. J.; Sibeck, D.; Chen, S.; Breneman, A.

    2017-01-01

    We analyze a wave event that occurred near noon between 07:03 and 07:08 UT on 23 February 2014 detected by the Van Allen Probes B spacecraft, where waves in the lower hybrid frequency range (LHFR) and electromagnetic ion cyclotron (EMIC) waves are observed to be highly correlated, with Pearson correlation coefficient of 0.86. We assume that the correlation is the result of LHFR wave generation by the ions' polarization drift in the electric field of the EMIC waves. To check this assumption the drift velocities of electrons and H+, He+, and O+ ions in the measured EMIC wave electric field were modeled. Then the LHFR wave linear instantaneous growth rates for plasma with these changing drift velocities and different plasma compositions were calculated. The time distribution of these growth rates, their frequency distribution, and the frequency dependence of the ratio of the LHFR wave power spectral density (PSD) parallel and perpendicular to the ambient magnetic field to the total PSD were found. These characteristics of the growth rates were compared with the corresponding characteristics of the observed LHFR activity. Reasonable agreement between these features and the strong correlation between EMIC and LHFR energy densities support the assumption that the LHFR wave generation can be caused by the ions' polarization drift in the electric field of an EMIC wave.

  6. Electrosmog. Effects of high-frequency electromagnetic waves on health. Pt. 1. Elektrosmog. Gesundheitliche Wirkungen hochfrequenter elektromagnetischer Wellen. T. 1

    Energy Technology Data Exchange (ETDEWEB)

    Matthes, R. (Bundesamt fuer Strahlenschutz, Oberschleissheim (Germany). Inst. fuer Strahlenhygiene)

    1993-10-01

    (1) The concept of Electrosmog concerns technically electromagnetic waves and fields of variable frequency and intensity. In our environment, high frequency fields come almost entirely from man-made sources. (2) High frequency electromagnetic fields can cause physical effects either directly or indirectly - eg through conductive materials. Thermal effects are the most prominent. The action of force mediated by the field can cause the loadig of there electric charges in the body. (3) The amount of energy absorbed by a fabric can be calculated from the intensity of the yield and the conductivity of the material. (4) In-vitro studies have suggested that high frequency fields affect the cell membranes and can cause changes in their permeability, enzyme activity and immune responses; although there are no proven results blaming high frequency fields for such mutations, and effects on cell proliferation have not been ascertained. (5) A basic limit of O-4 W/kg has been set internationally for work-related exposure, according to public health considerations, and the limit for the general public is 0.08 W/kg. (6) These basic limits are generally kept as a minimum requirement, and generally exposure is a hot lower. When high frequency equipment is in use nearby, measures must be taken to ensure that sefety limits are upheld and injury avoided, to the eyes in particular. (orig./MG)

  7. Electromagnetic wave energy converter

    Science.gov (United States)

    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.

  8. "Hearing" Electromagnetic Waves

    Science.gov (United States)

    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…

  9. "Hearing" Electromagnetic Waves

    Science.gov (United States)

    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…

  10. Millimeter waves or extremely high frequency electromagnetic fields in the environment: what are their effects on bacteria?

    Science.gov (United States)

    Soghomonyan, Diana; Trchounian, Karen; Trchounian, Armen

    2016-06-01

    Millimeter waves (MMW) or electromagnetic fields of extremely high frequencies at low intensity is a new environmental factor, the level of which is increased as technology advance. It is of interest that bacteria and other cells might communicate with each other by electromagnetic field of sub-extremely high frequency range. These MMW affected Escherichia coli and many other bacteria, mainly depressing their growth and changing properties and activity. These effects were non-thermal and depended on different factors. The significant cellular targets for MMW effects could be water, cell plasma membrane, and genome. The model for the MMW interaction with bacteria is suggested; a role of the membrane-associated proton FOF1-ATPase, key enzyme of bioenergetic relevance, is proposed. The consequences of MMW interaction with bacteria are the changes in their sensitivity to different biologically active chemicals, including antibiotics. Novel data on MMW effects on bacteria and their sensitivity to different antibiotics are presented and discussed; the combined action of MMW and antibiotics resulted with more strong effects. These effects are of significance for understanding changed metabolic pathways and distinguish role of bacteria in environment; they might be leading to antibiotic resistance in bacteria. The effects might have applications in the development of technique, therapeutic practices, and food protection technology.

  11. Electromagnetic fields and waves

    CERN Document Server

    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...

  12. Noise in a coupling electromagnetic detecting system for high frequency gravitational waves

    Institute of Scientific and Technical Information of China (English)

    Li Jin; Li Fang-Yu; Zhong Yuan-Hong

    2009-01-01

    This paper discusses the basic categories of noise in detecting high frequency gravitational waves in the microwave band (~0.1-10 GHz), which contain shot noise from the laser and the thermal radiation photons, thermal noise from statistical fluctuation of the thermal photons and fluctuation of the temperature, radiation press noise on the fractal membrane, the noise caused by the scattering of the Gaussian Beam (GB) in the detecting tube and noise in the microwave radiometers. The analysis shows that a reasonable signal-to-noise ratio may be achieved for a detecting device with the fixed power of GB (105 W), only when the temperature of the environment is no more than T=l K, and the optimal length of the microwave radiometers is about 0.3 m.

  13. Fractional Electromagnetic Waves

    CERN Document Server

    Gómez, J F; Bernal, J J; Tkach, V I; Guía, M

    2011-01-01

    In the present work we consider the electromagnetic wave equation in terms of the fractional derivative of the Caputo type. The order of the derivative being considered is 0 <\\gamma<1. A new parameter \\sigma, is introduced which characterizes the existence of the fractional components in the system. We analyze the fractional derivative with respect to time and space, for \\gamma = 1 and \\gamma = 1/2 cases.

  14. Electromagnetic ion cyclotron waves observed near the oxygen cyclotron frequency by ISEE 1 and 2

    Science.gov (United States)

    Fraser, B. J.; Samson, J. C.; Hu, Y. D.; Mcpherron, R. L.; Russell, C. T.

    1992-01-01

    The first results of observations of ion cyclotron waves by the elliptically orbiting ISEE 1 and 2 pair of spacecraft are reported. The most intense waves (8 nT) were observed in the outer plasmasphere where convection drift velocities 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. Computations of the experimental wave spectra during the passage through the plasmapause show that the spectral slots relate to the 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 is attributed to the modulation of this energy source by the Pc 5 waves seen at the same time.

  15. Electromagnetic waves in stratified media

    CERN Document Server

    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

  16. Some thermodynamic considerations on low frequency electromagnetic waves effects on cancer invasion and metastasis

    Science.gov (United States)

    Lucia, Umberto; Ponzetto, Antonio

    2017-02-01

    Cell membranes are the reason of the cell energy transfer. In cells energy transfer, thermo-electro-chemical processes and transports phenomena occur through their membranes. Cells can actively modify their behaviours in relation to any change of their environment. They waste heat into their environment. The analysis of irreversibility related to this wasted heat, to the ions transport and the related cell-environment pH changes represents a new useful approach to the study of the cells behaviour. This analysis allows also the explanation of the effects of electromagnetic fields on the cell behaviour, and to suggest how low intensity electromagnetic fields could represent a useful support to the present anticancer therapies.

  17. Electromagnetic van Kampen waves

    Energy Technology Data Exchange (ETDEWEB)

    Ignatov, A. M., E-mail: aign@fpl.gpi.ru [Russian Academy of Sciences, Prokhorov General Physics Institute (Russian Federation)

    2017-01-15

    The theory of van Kampen waves in plasma with an arbitrary anisotropic distribution function is developed. The obtained solutions are explicitly expressed in terms of the permittivity tensor. There are three types of perturbations, one of which is characterized by the frequency dependence on the wave vector, while for the other two, the dispersion relation is lacking. Solutions to the conjugate equations allowing one to solve the initial value problem are analyzed.

  18. Wave propagation in electromagnetic media

    CERN Document Server

    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...

  19. Hydraulic continuity and biological effects of low strength very low frequency electromagnetic waves: Case of microbial biofilm growth in water treatment.

    Science.gov (United States)

    Gérard, Merlin; Noamen, Omri; Evelyne, Gonze; Eric, Valette; Gilles, Cauffet; Marc, Henry

    2015-10-15

    This study aims to elucidate the interactions between water, subjected to electromagnetic waves of very low frequency (VLF) (kHz) with low strength electromagnetic fields (3.5 mT inside the coils), and the development of microbial biofilms in this exposed water. Experimental results demonstrate that in water exposed to VLF electromagnetic waves, the biomass of biofilm is limited if hydraulic continuity is achieved between the electromagnetic generator and the biofilm media. The measured amount of the biofilm's biomass is approximately a factor two lower for exposed biofilm than the non-exposed biofilm. Measurements of electromagnetic fields in the air and simulations exhibit very low intensities of fields (electromagnetic generator. Exposure to electric and magnetic fields of the quoted intensities cannot explain thermal and ionizing effects on the biofilm. A variable electrical potential with a magnitude close to 20 mV was detected in the tank in hydraulic continuity with the electromagnetic generator. The application of quantum field theory may help to explain the observed effects in this case.

  20. Focusing of electromagnetic waves

    Energy Technology Data Exchange (ETDEWEB)

    Dhayalan, V.

    1996-12-31

    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.

  1. Low and high frequency asymptotics acoustic, electromagnetic and elastic wave scattering

    CERN Document Server

    Varadan, VK

    2013-01-01

    This volume focuses on asymptotic methods in the low and high frequency limits for the solution of scattering and propagation problems. Each chapter is pedagogical in nature, starting with the basic foundations and ending with practical applications. For example, using the Geometrical Theory of Diffraction, the canonical problem of edge diffraction is first solved and then used in solving the problem of diffraction by a finite crack. In recent times, the crack problem has been of much interest for its applications to Non-Destructive Evaluation (NDE) of flaws in structural materials.

  2. Fundamentals of electromagnetics 2 quasistatics and waves

    CERN Document Server

    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

  3. Interference of electromagnetic waves in dynamic metabolism

    Institute of Scientific and Technical Information of China (English)

    黄卡玛; 唐敬贤; 刘永清; 徐兰

    1995-01-01

    Life is a continuous process of the dynamic metabolism.The influence of electromagneticwaves on the process of metabolism cannot be neglected.Here a new theory of electromagnetic interference inthe dynamic metabolism of life is proposed.The statistical dynamic equations of ion and free radical in thebiochemical reaction radiated by electromagnetic waves are given.The intensity of electromagnetic interferencecould be described with an interference factor.Good agreement can be seen between the calculated and meas-ured results for a famous experiment of radio-frequency radiation-induced calcium ion efflux enhancement.

  4. Stimulated electromagnetic emission and plasma line during pump wave frequency stepping near 4th electron gyroharmonic at HAARP

    Science.gov (United States)

    Grach, Savely; Sergeev, Evgeny; Shindin, Alexey; Mishin, Evgeny; Watkins, Brenton

    Concurrent observations of stimulated (secondary) electromagnetic emissions (SEE) and incoherent plasma line (PL) backscatter from the MUIR radar during HF pumping of the ionosphere by the HAARP heating facility (62.4(°) °N, 145.15(°) W, magnetic inclination α = 75.8^circ) with the pump wave (PW) frequency sweeps about the fourth electron gyroharmonic (4f_c) are presented. The PW frequency f0 was changed every 0.2 s in a 1-kHz step, i.e. with the rate of r_{f_0}=5 kHz/s. PW was transmitted at the magnetic zenith (MZ). Prior to sweeping, PW was transmitted continuously (CW) during 2 min at f_0 = 5730 kHz 4f_c, namely BUM_S and BUM_D. The former (stationary broad upshifted maxiμm) peaks at Delta f_{BUMs} approx f0 - nfc (d) + 15-20 kHz and is a typical SEE spectral feature. The latter, the dynamic BUM_D at smaller Delta f, is observed only at high pump powers (ERP=1.7 GW) and corresponds to artificial descending plasma layers created in the F-region ionosphere [1]. In the experiment in question, the BUM_D was present for f_0> f^*, where f^* was 5805-5815 kHz during stepping up and sim 10 kHz less for stepping down, and located 8-10 km below the background F-layer. The miniμm DM which indicated that f_0=4f_c=f_{uh} in the background ionospheric plasma, was sim 5760 kHz. The PL was observed only for f_0 4f_c. In this case we obtained Delta f_g sim 8-13 kHz corresponding to Delta h sim - 4 km. The PL has never been observed for f_0>f^*$. \\ 1. Sergeev E., Grach S., et al. //Phys. Rev. Lett., 110 (2013), 065002.

  5. Electromagnetic Generators and Detectors of Gravitational Waves

    CERN Document Server

    Grishchuk, L P

    2003-01-01

    The renewed serious interest to possible practical applications of gravitational waves is encouraging. Building on previous work, I am arguing that the strong variable electromagnetic fields are appropriate systems for the generation and detection of high-frequency gravitational waves (HFGW). The advantages of electromagnetic systems are clearly seen in the proposed complete laboratory experiment, where one has to ensure the efficiency of, both, the process of generation and the process of detection of HFGW. Within the family of electromagnetic systems, one still has a great variety of possible geometrical configurations, classical and quantum states of the electromagnetic field, detection strategies, etc. According to evaluations performed 30 years ago, the gap between the HFGW laboratory signal and its level of detectability is at least 4 orders of magnitude. Hopefully, new technologies of today can remove this gap and can make the laboratory experiment feasible. The laboratory experiment is bound to be exp...

  6. 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...

  7. Gravitational Wave Track in the Electromagnetic Field of the Earth in the Infra-Low Frequency Range

    Science.gov (United States)

    Grunskaya, L. V.; Isakevich, V. V.; Isakevich, D. V.; Luk'ianov, V. E.

    2017-01-01

    Signals in the infra-low frequency range in the electric and geomagnetic fields of the Earth have been detected, corresponding to frequencies of gravitational waves (GWs) emitted by a series of binary star systems (BSS). The coherence of the detected signals has been investigated. The amplitude characteristics of signals in the electric and geomagnetic fields at GW frequencies of BSS are estimated. The estimates of the amplitudes of the detected signals are in line with model estimates.

  8. Electromagnetic fields and waves

    CERN Document Server

    Rojansky, Vladimir

    2012-01-01

    This comprehensive introduction to classical electromagnetic theory covers the major aspects, including scalar fields, vectors, laws of Ohm, Joule, Coulomb, Faraday, Maxwell's equation, and more. With numerous diagrams and illustrations.

  9. Line geometry and electromagnetism II: wave motion

    CERN Document Server

    Delphenich, D H

    2013-01-01

    The fundamental role of line geometry in the study of wave motion is first introduced in the general context by way of the tangent planes to the instantaneous wave surfaces, in which it is first observed that the possible frequency-wave number 1-forms are typically constrained by a dispersion law that is derived from a constitutive law by way of the field equations. After a general review of the basic concepts that relate to quadratic line complexes, these geometric notions are applied to the study of electromagnetic waves, in particular.

  10. Radiation and propagation of electromagnetic waves

    CERN Document Server

    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

  11. Electromagnetic waves in a strong Schwarzschild plasma

    Energy Technology Data Exchange (ETDEWEB)

    Daniel, J.; Tajima, T.

    1996-11-01

    The physics of high frequency electromagnetic waves in a general relativistic plasma with the Schwarzschild metric is studied. Based on the 3 + 1 formalism, we conformalize Maxwell`s equations. The derived dispersion relations for waves in the plasma contain the lapse function in the plasma parameters such as in the plasma frequency and cyclotron frequency, but otherwise look {open_quotes}flat.{close_quotes} Because of this property this formulation is ideal for nonlinear self-consistent particle (PIC) simulation. Some of the physical consequences arising from the general relativistic lapse function as well as from the effects specific to the plasma background distribution (such as density and magnetic field) give rise to nonuniform wave equations and their associated phenomena, such as wave resonance, cutoff, and mode-conversion. These phenomena are expected to characterize the spectroscopy of radiation emitted by the plasma around the black hole. PIC simulation results of electron-positron plasma are also presented.

  12. Proposed electromagnetic wave energy converter

    Science.gov (United States)

    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.

  13. [Comparative evaluation of the efficiency of the effect of very high frequency electromagnetic waves on platelet functional activity].

    Science.gov (United States)

    Kirichuk, V F; Maĭborodin, A V; Volin, M V; Krenitskiĭ, A P; Tupikin, V D

    2001-01-01

    A comparative analysis was made of the effect of two kinds of EMI MMD-radiation: EMI MMD-waves, generated by a vehicle "Jav-1 M" (42.2 and 53.5 HHz), and EMI MMD-waves exerting influence with frequencies of molecular spectrum of radiation and nitric oxide absorption (150.176-150.644 HHz), obtained with a specially created generator, with respect to their influence on the functional ability of platelets of unstable angina pectoris patients. It was shown that in vitro EMI MMD-fluctuations with frequencies of molecular spectrum of radiation and nitric oxide absorption exert a stronger inhibiting influence on the functional activity of platelets of unstable angina pectoris patients. Features of the action of various kinds of EMI MMD-effect on the activative-high-speed characteristics of platelet aggregation are shown.

  14. Axion-Electromagnetic Waves

    CERN Document Server

    Visinelli, Luca

    2014-01-01

    We extend the duality symmetry between the electric and the magnetic fields to the case in which an additional axion-like term is present, and we derive the set of Maxwell's equations that preserves this symmetry. This new set of equations allows for a gauge symmetry extending the ordinary symmetry in the classical electrodynamics. We obtain explicit solutions for the new set of equations in the absence of external sources, and we discuss the implications of a new internal symmetry between the axion field and the electromagnetic gauge potential.

  15. Electromagnetic radiation accompanying gravitational waves from black hole binaries

    Science.gov (United States)

    Dolgov, A.; Postnov, K.

    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.

  16. Millimeter waves: acoustic and electromagnetic.

    Science.gov (United States)

    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.

  17. Attenuation of low-frequency electromagnetic wave in the thin sheath enveloping a high-speed vehicle upon re-entry

    Science.gov (United States)

    Liu, DongLin; Li, XiaoPing; Liu, YanMing; Xie, Kai; Bai, BoWen

    2017-02-01

    Low-frequency (LF) electromagnetic (EM) waves are suggested as potentially solving "radio blackout" caused by a plasma sheath enveloping a high-speed vehicle on re-entry. However, the traditional plasma absorption theory neglects the fact that the plasma sheath is electrically small compared to LF EM wavelengths. To understand clearly the attenuation of such waves through the plasma sheath, different attenuation mechanisms for the electric field (SE) and magnetic field (SH) were studied using the equivalent circuit approach. Analytical expressions were derived by modeling the plasma sheath as a spherical shell, and numerical simulations were performed to validate the effectiveness of the expressions. SE and SH are calculated for various plasma parameter settings; the EM wave attenuations obtained from plasma absorption theory are used for comparison. Results show that, instead of SE and SH being equal in the plasma absorption theory, SE and SH are no longer the same for electrically small sizes. Whereas |SH| is close to that from plasma absorption theory, |SE| is much higher. Further analysis shows that |SH| is a function of the ratio of electron density (ne) and collision frequency (ve) and increases with increasing ne/ve. Numerical simulations with radio-attenuation-measurement-C-like vehicle's plasma sheath parameters are performed and the results show that the magnetic field attenuation in the front part of the vehicle is much lower than in the rear. So it is suggested to place the magnetic loop antenna in the very front part of the vehicle. Finally, SH at different frequencies are calculated using plasma sheath parameter values simulating the re-entry phase of a radio-attenuation measurement-C vehicle and results show that such a vehicle might overcome radio blackout during the entire re-entry phase if systems operating below 3 MHz and above the L-band are combined with a lower-frequency system working below Earth's ionosphere and a higher-frequency system

  18. Global Simulation of Electromagnetic Ion Cyclotron Waves

    Science.gov (United States)

    Khazanov, George V.; Gallagher, D. L.; Kozyra, J. U.

    2007-01-01

    It is very well known that the effects of electromagnetic ion cyclotron (EMIC) waves on ring current (RC) ion and radiation belt (RB) electron dynamics strongly depend on such particle/wave characteristics as the phase-space distribution function, frequency, wave-normal angle, wave energy, and the form of wave spectral energy density. The consequence is that accurate modeling of EMIC waves and RC particles requires robust inclusion of the interdependent dynamics of wave growth/damping, wave propagation, and particles. Such a self-consistent model is being progressively developed by Khazanov et al. This model is based on a system of coupled kinetic equations for the RC and EMIC wave power spectral density along with the ray tracing equations. We will discuss the recent progress in understanding EMIC waves formation mechanisms in the inner magnetosphere. This problem remains unsettled in spite of many years of experimental and theoretical studies. Modern satellite observations by CRRES, Polar and Cluster still do not reveal the whole picture experimentally since they do not stay long enough in the generation region to give a full account of all the spatio-temporal structure of EMIC waves. The complete self-consistent theory taking into account all factors significant for EMIC waves generation remains to be developed. Several mechanisms are discussed with respect to formation of EMIC waves, among them are nonlinear modification of the ionospheric reflection by precipitating energetic protons, modulation of ion-cyclotron instability by long-period (Pc3/4) pulsations, reflection of waves from layers of heavy-ion gyroresonances, and nonlinearities of wave generation process. We show that each of these mechanisms have their attractive features and explains certain part experimental data but any of them, if taken alone, meets some difficulties when compared to observations. We conclude that development of a refined nonlinear theory and further correlated analysis of modern

  19. Electromagnetic waves in variable media

    Energy Technology Data Exchange (ETDEWEB)

    Brosa, Ulrich [Brosa GmbH, Amoeneburg (Germany); Marburg Univ. (Germany)

    2012-03-15

    Two methods are explained to exactly solve Maxwell's equations where permittivity, permeability, and conductivity may vary in space. In the constitutive relations, retardation is regarded. If the material properties depend but on one coordinate, general solutions are derived. If the properties depend on two coordinates, geometrically restricted solutions are obtained. Applications to graded reflectors, especially to dielectric mirrors, to filters, polarizers, and to waveguides, plain and cylindrical, are indicated. New foundations for the design of optical instruments, which are centered around an axis, and for the design of invisibility cloaks, plain and spherical, are proposed. The variability of material properties makes possible effects which cannot happen in constant media, e.g. stopping the flux of electromagnetic energy without loss. As a consequence, spherical devices can be constructed which bind electromagnetic waves. (orig.)

  20. Analytic descriptions of cylindrical electromagnetic waves in a nonlinear medium.

    Science.gov (United States)

    Xiong, Hao; Si, Liu-Gang; Yang, Xiaoxue; Wu, Ying

    2015-06-15

    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.

  1. Analytic descriptions of cylindrical electromagnetic waves in a nonlinear medium

    Science.gov (United States)

    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

  2. Electromagnetic waves in a magnetized plasma near the critical surface

    Energy Technology Data Exchange (ETDEWEB)

    Timofeev, Aleksandr V [Russian Research Centre ' Kurchatov Institute' , Moscow (Russian Federation)

    2004-06-30

    Electromagnetic waves in a plasma in a magnetic field give rise to enhanced refraction, produce a change in polarization, and cause electromagnetic energy to flow from one wave mode to another when propagating near the critical surface (CS), the one where the electron Langmuir frequency is equal to the wave frequency. A simple unified model of all phenomena taking place near the CS is proposed. These phenomena are due to electromagnetic waves linearly interacting with electron Langmuir oscillations which are localized at the CS in a cold plasma. This interaction manifests itself most strikingly in electron Langmuir oscillation energy escaping directly into a vacuum in the form of electromagnetic radiation. (reviews of topical problems)

  3. Electromagnetic wave propagation in alternating material-metamaterial layered structures

    CERN Document Server

    Carrera-Escobedo, V H

    2016-01-01

    Using the transfer matrix method, we examine the parametric behavior of the transmittance of an electromagnetic plane wave propagating in the lossless regime through a periodic multilayered system as a function of the frequency and angle of incidence of the electromagnetic wave for the case in which the periodic structure comprises alternating material-metamaterial layers. A specific example of high transmittance at any angle of incidence in the visible region of the spectrum is identified

  4. The motion of a charged particle in the field of a frequency-modulated electromagnetic wave and in the constant magnetic field

    Directory of Open Access Journals (Sweden)

    Nikolay S. Akintsov

    2015-12-01

    The formulae for the mean kinetic energy of a relativistic charged particle as a function of initial conditions, electromagnetic wave amplitude, wave intensity and its polarization parameter were obtained. The different cases of initial conditions of a charged particle motion and of a wave polarization were investigated. The obtained results can be put to use when studying the high-temperature plasma formed on the surface of the target and when searching for new modes of laser- plasma interaction.

  5. Electromagnetic wave energy conversion research

    Science.gov (United States)

    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.

  6. Low-frequency electromagnetic field in a Wigner crystal

    CERN Document Server

    Stupka, Anton

    2016-01-01

    Long-wave low-frequency oscillations are described in a Wigner crystal by generalization of the reverse continuum model for the case of electronic lattice. The internal self-consistent long-wave electromagnetic field is used to describe the collective motions in the system. The eigenvectors and eigenvalues of the obtained system of equations are derived. The velocities of longitudinal and transversal sound waves are found.

  7. 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.

  8. Spheroidal Wave Functions in Electromagnetic Theory

    Science.gov (United States)

    Li, Le-Wei; Kang, Xiao-Kang; Leong, Mook-Seng

    2001-11-01

    The flagship monograph addressing the spheroidal wave function and its pertinence to computational electromagnetics Spheroidal Wave Functions in Electromagnetic Theory presents in detail the theory of spheroidal wave functions, its applications to the analysis of electromagnetic fields in various spheroidal structures, and provides comprehensive programming codes for those computations. The topics covered in this monograph include: Spheroidal coordinates and wave functions Dyadic Green's functions in spheroidal systems EM scattering by a conducting spheroid EM scattering by a coated dielectric spheroid Spheroid antennas SAR distributions in a spheroidal head model The programming codes and their applications are provided online and are written in Mathematica 3.0 or 4.0. Readers can also develop their own codes according to the theory or routine described in the book to find subsequent solutions of complicated structures. Spheroidal Wave Functions in Electromagnetic Theory is a fundamental reference for scientists, engineers, and graduate students practicing modern computational electromagnetics or applied physics.

  9. Efficient transformer for electromagnetic waves

    Science.gov (United States)

    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.

  10. Estimation of electron concentration in plasma and plasma frequency in the vicinity of a hypersonic aircraft that moves in atmosphere and analysis of propagation frequencies of electromagnetic waves in such plasma

    Science.gov (United States)

    Fedorov, V. A.

    2016-05-01

    Electron concentration in plasma and plasma frequency are estimated for the plasma that is formed in the vicinity of a hypersonic aircraft that moves in atmosphere. The frequencies of electromagnetic waves that may propagate in plasma emerging in the vicinity of the aircraft are determined. Formulas that make it possible to analytically (rather than graphically) calculate electron concentration in plasma at altitudes of 30, 60, and 90 km are derived for two speeds. Several specific features of variations in the electron concentration in plasma depending on the above altitudes and speeds are presented. Quasi-periodic variations in the plasma concentration can be obtained using an increase and decrease in the speed of aircraft.

  11. Integral methods in low-frequency electromagnetics

    CERN Document Server

    Solin, Pavel; Karban, Pavel; Ulrych, Bohus

    2009-01-01

    A modern presentation of integral methods in low-frequency electromagnetics This book provides state-of-the-art knowledge on integral methods in low-frequency electromagnetics. Blending theory with numerous examples, it introduces key aspects of the integral methods used in engineering as a powerful alternative to PDE-based models. Readers will get complete coverage of: The electromagnetic field and its basic characteristics An overview of solution methods Solutions of electromagnetic fields by integral expressions Integral and integrodifferential methods

  12. Artificial excitation of ELF waves with frequency of Schumann resonance

    Science.gov (United States)

    Streltsov, A. V.; Guido, T.; Tulegenov, B.; Labenski, J.; Chang, C.-L.

    2014-11-01

    We report results from the experiment aimed at the artificial excitation of extremely low-frequency (ELF) electromagnetic waves with frequencies corresponding to the frequency of Schumann resonance. Electromagnetic waves with these frequencies can form a standing pattern inside the spherical cavity formed by the surface of the Earth and the ionosphere. In the experiment the ELF waves were excited by heating the ionosphere with X-mode HF electromagnetic waves generated at the High Frequency Active Auroral Research Program (HAARP) facility in Alaska. The experiment demonstrates that heating of the ionosphere can excite relatively large-amplitude electromagnetic waves with frequencies in the range 7.8-8.0 Hz when the ionosphere has a strong F layer, the frequency of the HF radiation is in the range 3.20-4.57 MHz, and the electric field greater than 5 mV/m is present in the ionosphere.

  13. Electromagnetic ion cyclotron waves in the plasma depletion layer

    Science.gov (United States)

    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.

  14. Scattering theory of stochastic electromagnetic light waves.

    Science.gov (United States)

    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.

  15. Vacuum amplification of the high-frequency electromagnetic radiation

    OpenAIRE

    Vilkovisky, G. A.

    1998-01-01

    When an electrically charged source is capable of both emitting the electromagnetic waves and creating charged particles from the vacuum, its radiation gets so much amplified that only the backreaction of the vacuum makes it finite. The released energy and charge are calculated in the high-frequency approximation. The technique of expectation values is advanced and employed.

  16. Plant Responses to High Frequency Electromagnetic Fields

    Directory of Open Access Journals (Sweden)

    Alain Vian

    2016-01-01

    Full Text Available High frequency nonionizing electromagnetic fields (HF-EMF that are increasingly present in the environment constitute a genuine environmental stimulus able to evoke specific responses in plants that share many similarities with those observed after a stressful treatment. Plants constitute an outstanding model to study such interactions since their architecture (high surface area to volume ratio optimizes their interaction with the environment. In the present review, after identifying the main exposure devices (transverse and gigahertz electromagnetic cells, wave guide, and mode stirred reverberating chamber and general physics laws that govern EMF interactions with plants, we illustrate some of the observed responses after exposure to HF-EMF at the cellular, molecular, and whole plant scale. Indeed, numerous metabolic activities (reactive oxygen species metabolism, α- and β-amylase, Krebs cycle, pentose phosphate pathway, chlorophyll content, terpene emission, etc. are modified, gene expression altered (calmodulin, calcium-dependent protein kinase, and proteinase inhibitor, and growth reduced (stem elongation and dry weight after low power (i.e., nonthermal HF-EMF exposure. These changes occur not only in the tissues directly exposed but also systemically in distant tissues. While the long-term impact of these metabolic changes remains largely unknown, we propose to consider nonionizing HF-EMF radiation as a noninjurious, genuine environmental factor that readily evokes changes in plant metabolism.

  17. Electromagnetic wave analogue of electronic diode

    OpenAIRE

    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 ...

  18. Electromagnetic wave analogue of electronic diode

    OpenAIRE

    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 ...

  19. Linear electromagnetic wave equations in materials

    Science.gov (United States)

    Starke, R.; Schober, G. A. H.

    2017-09-01

    After a short review of microscopic electrodynamics in materials, we investigate the relation of the microscopic dielectric tensor to the current response tensor and to the full electromagnetic Green function. Subsequently, we give a systematic overview of microscopic electromagnetic wave equations in materials, which can be formulated in terms of the microscopic dielectric tensor.

  20. Scattering of electromagnetic waves by obstacles

    CERN Document Server

    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.

  1. Dispersion of Own Frequency of Ion-Dipole by Supersonic Transverse Wave in Solid

    Directory of Open Access Journals (Sweden)

    Minasyan V.

    2010-10-01

    Full Text Available First, we predict an existence of transverse electromagnetic field formed by supersonic transverse wave in solid. This electromagnetic wave acquires frequency and speed of sound, and it propagates along of direction propagation of supersonic wave. We also show that own frequency of ion-dipole depends on frequency of supersonic transverse wave.

  2. Ionospheric electron acceleration by electromagnetic waves near regions of plasma resonances

    Science.gov (United States)

    Villalon, Elena

    1989-03-01

    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.

  3. High latitude electromagnetic plasma wave emissions

    Science.gov (United States)

    Gurnett, D. A.

    1983-01-01

    The principal types of electromagnetic plasma wave emission produced in the high latitude auroral regions are reviewed. Three types of radiation are described: auroral kilometric radiation, auroral hiss, and Z mode radiation. Auroral kilometric radiation is a very intense radio emission generated in the free space R-X mode by electrons associated with the formation of discrete auroral arcs in the local evening. Theories suggest that this radiation is an electron cyclotron resonance instability driven by an enhanced loss cone in the auroral acceleration region at altitudes of about 1 to 2 R sub E. Auroral hiss is a somewhat weaker whistler mode emission generated by low energy (100 eV to 10 keV) auroral electrons. The auroral hiss usually has a V shaped frequency time spectrum caused by a freqency dependent beaming of the whistler mode into a conical beam directed upward or downward along the magnetic field.

  4. Propagation of Electromagnetic Wave in Coaxial Conical Transverse Electromagnetic Wave Cell

    Institute of Scientific and Technical Information of China (English)

    LIU Xingxun; ZHANG Tao; QI Wangquan

    2015-01-01

    In order to solve the problem of broadband field probes calibration with only selected discrete frequencies above 1 GHz, a sweep-frequency calibration technology based on a coaxial conical(co-conical) cell is researched. Existing research is only qualitative because of the complexity of theoretical calculations. For designing a high performance cell, a mathematic model of high-order modes transmission is built according to the geometrical construction of co-conical. The associated Legendre control functions of high-order modes are calculated by using recursion methodology and the numerical calculation roots are presented with different half angles of inner and outer conductor. Relationship between roots and high-order modes transmission is analyzed, when the half angles of inner conductor and outer conductor areθ1=1.5136° andθ2=8° respectively, the co-conical cell has better performance for fewer transmitting high-order modes. The propagation process of the first three transmitting modes wave is simulated in CST-MWS software from the same structured co-conical. The simulation plots show that transmission of high-order modes appears with electromagnetic wave reflection, then different high-order mode transmission has different cut-off region and each cut-off region is determined by its cut-off wavelength. This paper presents numerical calculation data and theoretical analysis to design key structural parameters for the co-conical transverse electromagnetic wave cell(co-conical TEM cell).

  5. Propagation of electromagnetic wave in coaxial conical transverse electromagnetic wave cell

    Science.gov (United States)

    Liu, Xingxun; Zhang, Tao; Qi, Wangquan

    2015-11-01

    In order to solve the problem of broadband field probes calibration with only selected discrete frequencies above 1 GHz, a sweep-frequency calibration technology based on a coaxial conical(co-conical) cell is researched. Existing research is only qualitative because of the complexity of theoretical calculations. For designing a high performance cell, a mathematic model of high-order modes transmission is built according to the geometrical construction of co-conical. The associated Legendre control functions of high-order modes are calculated by using recursion methodology and the numerical calculation roots are presented with different half angles of inner and outer conductor. Relationship between roots and high-order modes transmission is analyzed, when the half angles of inner conductor and outer conductor are θ 1=1.5136° and θ 2=8° respectively, the co-conical cell has better performance for fewer transmitting high-order modes. The propagation process of the first three transmitting modes wave is simulated in CST-MWS software from the same structured co-conical. The simulation plots show that transmission of high-order modes appears with electromagnetic wave reflection, then different high-order mode transmission has different cut-off region and each cut-off region is determined by its cut-off wavelength. This paper presents numerical calculation data and theoretical analysis to design key structural parameters for the co-conical transverse electromagnetic wave cell(co-conical TEM cell).

  6. Tree-wave mixing of ordinary and backward electromagnetic waves: extraordinary transients

    CERN Document Server

    Slabko, Vitaly V; Tkachenko, Viktor A; Myslivets, Sergey A

    2016-01-01

    Three-wave mixing of ordinary and backward electromagnetic waves in pulsed regime is investigated in the metamaterials, which enable co-existence and phase matching of such waves. It is shown that opposite direction of phase velocity and energy flux in backward waves gives rise to extraordinary transient processes in greatly enhanced optical parametric amplification and in frequency up or down shifting nonlinear reflectivity. The discovered transients resemble slowed response of an oscillator on pulsed excitation in the vicinity of its resonance

  7. Propagation of SLF/ELF electromagnetic waves

    CERN Document Server

    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).

  8. On the gravitational fields created by the electromagnetic waves

    OpenAIRE

    Loinger, A.; Marsico, T.

    2011-01-01

    We show that the Maxwell equations describing an electromagnetic wave are a mathematical consequence of the Einstein equations for the same wave. This fact is significant for the problem of the Einsteinian metrics corresponding to the electromagnetic waves.

  9. Terrestrial propagation of long electromagnetic waves

    CERN Document Server

    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

  10. Exact plane gravitational waves and electromagnetic fields

    CERN Document Server

    Montanari, E; Montanari, Enrico; Calura, Mirco

    2000-01-01

    The behaviour of a "test" electromagnetic field in the background of an exactgravitational plane wave is investigated in the framework of Einstein's generalrelativity. We have expressed the general solution to the de Rham equations asa Fourier-like integral. In the general case we have reduced the problem to aset of ordinary differential equations and have explicitly written the solutionin the case of linear polarization of the gravitational wave. We have expressedour results by means of Fermi Normal Coordinates (FNC), which define the properreference frame of the laboratory. Moreover we have provided some "gedankenexperiments", showing that an external gravitational wave induces measurableeffects of non tidal nature via electromagnetic interaction. Consequently it isnot possible to eliminate gravitational effects on electromagnetic field, evenin an arbitrarily small spatial region around an observer freely falling in thefield of a gravitational wave. This is opposite to the case of mechanicalinteraction invo...

  11. Electromagnetic and Gravitational Waves: the Third Dimension

    CERN Document Server

    Marsh, Gerald E

    2011-01-01

    Plane electromagnetic and gravitational waves interact with particles in such a way as to cause them to oscillate not only in the transverse direction but also along the direction of propagation. The electromagnetic case is usually shown by use of the Hamilton-Jacobi equation and the gravitational by a transformation to a local inertial frame. Here, the covariant Lorentz force equation and the second order equation of geodesic deviation followed by the introduction of a local inertial frame are respectively used. It is often said that there is an analogy between the motion of charged particles in the field of an electromagnetic wave and the motion of test particles in the field of a gravitational wave. This analogy is examined and found to be rather limited. It is also shown that a simple special relativistic relation leads to an integral of the motion, characteristic of plane waves, that is satisfied in both cases.

  12. Aharonov-Bohm phase for an electromagnetic wave background

    Energy Technology Data Exchange (ETDEWEB)

    Bright, Max [California State University Fresno, Department of Physics, Fresno, CA (United States); Singleton, Douglas [California State University Fresno, Department of Physics, Fresno, CA (United States); UNESP-Univ. Estadual Paulista, ICTP South American Institute for Fundamental Research, Sao Paulo, SP (Brazil); Yoshida, Atsushi [University of Virginia, Department of Physics, Charlottesville, VA (United States); Hue University College of Education, Hue (Viet Nam)

    2015-09-15

    The canonical Aharonov-Bohm effect is usually studied with time-independent potentials. In this work, we investigate the Aharonov-Bohm phase acquired by a charged particle moving in time-dependent potentials. In particular, we focus on the case of a charged particle moving in the time-varying field of a plane electromagnetic wave. We work out the Aharonov-Bohm phase using both the potential (i.e. circular integral A{sub μ} dx{sup μ}) and the field (i.e. (1)/(2) ∫ F{sub μν}dσ{sup μν}) forms of the Aharonov-Bohm phase. We give conditions in terms of the parameters of the system (frequency of the electromagnetic wave, the size of the space-time loop, amplitude of the electromagnetic wave) under which the time-varying Aharonov-Bohm effect could be observed. (orig.)

  13. Study of a condition for the mode conversion from purely perpendicular electrostatic waves to electromagnetic waves

    Science.gov (United States)

    Kalaee, Mohammad Javad; Katoh, Yuto

    2016-07-01

    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.

  14. Low-Frequency Electromagnetic Backscattering from Tunnels

    Energy Technology Data Exchange (ETDEWEB)

    Casey, K; Pao, H

    2007-01-16

    Low-frequency electromagnetic scattering from one or more tunnels in a lossy dielectric half-space is considered. The tunnel radii are assumed small compared to the wavelength of the electromagnetic field in the surrounding medium; a tunnel can thus be modeled as a thin scatterer, described by an equivalent impedance per unit length. We examine the normalized backscattering width for cases in which the air-ground interface is either smooth or rough.

  15. Electromagnetic wave analogue of electronic diode

    CERN Document Server

    Shadrivov, Ilya V; 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 an extraordinary strong nonlinear wave propagation effect in the same way as electronic diode function is provided by a 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 differing by a factor of 65.

  16. Resonant circuit which provides dual-frequency excitation for rapid cycling of an electromagnet

    Science.gov (United States)

    Praeg, W.F.

    1982-03-09

    Disclosed is a novel ring-magnet control circuit that permits synchrotron repetition rates much higher than the frequency of the sinusoidal guide field of the ring magnet during particle acceleration. The control circuit generates sinusoidal excitation currents of different frequencies in the half waves. During radio-frequency acceleration of the synchrotron, the control circuit operates with a lower frequency sine wave and, thereafter, the electromagnets are reset with a higher-frequency half sine wave.

  17. Electromagnetic aquametry electromagnetic wave interaction with water and moist substances

    CERN Document Server

    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.

  18. Electron beam injection during active experiments. I - Electromagnetic wave emissions

    Science.gov (United States)

    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.

  19. Time reversal techniques in electromagnetic wave propagation

    Science.gov (United States)

    Yi, Jiang

    The time reversal method is a novel scheme utilizing the scattering components in a highly cluttered environment to achieve super-resolution focusing beyond Rayleigh criteria. In acoustics, time reversal effects are comprehensively analyzed and utilized in underwater target detection and communication. Successful demonstrations of the time reversal method using low frequency waveform in acoustics have generated wide interest in utilizing time reversal method by radio frequency electromagnetic waves. However, applications of the time reversal method in electromagnetics are considered to be emerging research topics and lack extensive analyses and studies. In this thesis, we present a systematic study in which a series of novel time reversal techniques have been developed for target detection and imaging in highly cluttered environments where higher order scattering is substantial. This thesis also contributes to insightful understanding of basic time reversal properties in electromagnetic (EM) wave propagation in such environment. EM time reversal focusing and nulling effects using both single and multiple antennas are first demonstrated by FDTD simulations. Based on these properties, single antenna time reversal detection indicates significant enhancement in detection capability over traditional change detection scheme. A frequency selection scheme utilizing the frequencies with strong constructive interference between the target and background environment is developed to further improve the performance of the time reversal detector. Moreover, a novel time reversal adaptive interference cancellation (TRAIC) detection scheme developed based on TR properties can obtain null of the background through the time reversal nulling effect and achieve automatic focusing on the target through the time reversal focusing effect. Therefore, the detection ability, dynamic range and signal to noise ratio of a radar system can be significantly enhanced by the time reversal method

  20. Electromagnetic Cyclotron Waves in the Solar Wind: Wind Observation and Wave Dispersion Analysis

    Science.gov (United States)

    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.

  1. Exact plane gravitational waves and electromagnetic fields

    OpenAIRE

    Enrico MontanariUniversity of Ferrara and INFN sezione di Ferrara, Italy; Mirco Calura(University of Ferrara and INFN sezione di Ferrara, Italy)

    2000-01-01

    The behaviour of a "test" electromagnetic field in the background of an exact gravitational plane wave is investigated in the framework of Einstein's general relativity. We have expressed the general solution to the de Rham equations as a Fourier-like integral. In the general case we have reduced the problem to a set of ordinary differential equations and have explicitly written the solution in the case of linear polarization of the gravitational wave. We have expressed our ...

  2. Coupled seismic and electromagnetic wave propagation

    NARCIS (Netherlands)

    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, creat

  3. Electromagnetic wave propagations in conjugate metamaterials.

    Science.gov (United States)

    Xu, Yadong; Fu, Yangyang; Chen, Huanyang

    2017-03-06

    In this work, by employing field transformation optics, we deduce a special kind of materials called conjugate metamaterials, which can support intriguing electromagnetic wave propagations, such as negative refractions and lasing phenomena. These materials could also serve as substrates for making a subwavelength-resolution lens, and the so-called "perfect lens" is demonstrated to be a limiting case.

  4. Properties of electrons scattered on a strong plane electromagnetic wave with a linear polarization: classical treatment

    CERN Document Server

    Bogdanov, O V

    2014-01-01

    The relations among the components of the exit momenta of ultrarelativistic electrons scattered on a strong electromagnetic wave of a low (optical) frequency and linear polarization are established using the exact solutions to the equations of motion with radiation reaction included (the Landau-Lifshitz equation). It is found that the momentum components of the electrons traversed the electromagnetic wave depend weakly on the initial values of the momenta. These electrons are mostly scattered at the small angles to the direction of propagation of the electromagnetic wave. The maximum Lorentz factor of the electrons crossed the electromagnetic wave is proportional to the work done by the electromagnetic field and is independent of the initial momenta. The momentum component parallel to the electric field strength vector of the electromagnetic wave is determined only by the diameter of the laser beam measured in the units of the classical electron radius. As for the reflected electrons, they for the most part l...

  5. Electromagnetic Wave Shieding Effectiveness of Carbon Fiber Sheet Coated Ferrite Film by Microwave-Hydrothermal Process

    Science.gov (United States)

    Murakami, Ri Ichi; Yamamoto, Hidetoshi; Kim, Chan Kong; Yim, Cheol Mun; Kim, Yun Hae

    The developments of electromagnetic wave shielding materials are strongly required because the malfunction of electronic equipment, mobile phone and wireless LAN avoids. In this study, it was investigated that the electromagnetic shielding effectiveness of carbon fiber sheets were enhanced by the ferrite which was coated by the microwave hydrothermal process. For coated carbon fiber sheet, the effects of ferrite and lamination of carbon fiber textile on the electromagnetic wave shielding effectiveness were discussed. In the range of frequency (100 1 GHz), the electromagnetic wave shielding effectiveness was measured by using TEM-Cell. The electromagnetic wave shielding effectiveness was greater for the coated carbon fiber sheets than for the uncoated carbon fiber sheets. When the insulation film was located between two carbon fiber sheets, the electromagnetic wave shielding effectiveness increased.

  6. Molding acoustic, electromagnetic and water waves with a single cloak

    KAUST Repository

    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.

  7. Molding acoustic, electromagnetic and water waves with a single cloak.

    Science.gov (United States)

    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.

  8. Electromagnetic wave collapse in a radiation background.

    Science.gov (United States)

    Marklund, Mattias; Brodin, Gert; Stenflo, Lennart

    2003-10-17

    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.

  9. [The effect of electromagnetic waves of very high frequency of molecular spectra of radiation and absorption of nitric oxide on the functional activity of platelets].

    Science.gov (United States)

    Kirichuk, V F; Maĭborodin, A V; Volin, M V; Krenitskiĭ, A P; Tupikin, V D

    2001-01-01

    A study was made of the effect of electromagnetic EMI MMD-fluctuation on the frequencies of molecular spectra of radiation, and nitric oxide absorption under in vitro conditions on the functional activity of platelets in patients with unstable angina pectoris, with the help of a specially created generator. At amplitude-modulated and continuous modes of EMI MMD-irradiation of platelet-rich plasma for 5, 15 and 30 min the platelet functional activity decreases, which was shown up in reduction of their activation and fall of aggregative ability. The degree, to which platelet functional activity was inhibited, depended on the mode of irradiation and on duration of EMI MMD effect. The most obvious changes in platelet activation and in their readiness to aggregative response were observed at a continuous mode of irradiation within a 15 min interval.

  10. Effect of electromagnetic waves on human reproduction.

    Science.gov (United States)

    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.

  11. Propagation and linear mode conversion of magnetosonic and electromagnetic ion cyclotron waves in the radiation belts

    Science.gov (United States)

    Horne, Richard B.; Miyoshi, Yoshizumi

    2016-10-01

    Magnetosonic waves and electromagnetic ion cyclotron (EMIC) waves are important for electron acceleration and loss from the radiation belts. It is generally understood that these waves are generated by unstable ion distributions that form during geomagnetically disturbed times. Here we show that magnetosonic waves could be a source of EMIC waves as a result of propagation and a process of linear mode conversion. The converse is also possible. We present ray tracing to show how magnetosonic (EMIC) waves launched with large (small) wave normal angles can reach a location where the wave normal angle is zero and the wave frequency equals the so-called crossover frequency whereupon energy can be converted from one mode to another without attenuation. While EMIC waves could be a source of magnetosonic waves below the crossover frequency, magnetosonic waves could be a source of hydrogen band waves but not helium band waves.

  12. Perfect absorbers for electromagnetic wave, based on metamaterials

    Science.gov (United States)

    Yoo, Young Joon; Kim, Young Ju; Lee, YoungPak

    2015-10-01

    Metamaterials (MMs), which are not existing in nature, but artificially-engineered materials for controlling electromagnetic wave. MMs have attracted more and more research attentions, since they have shown greatly novel properties such as left-handed behavior, negative refractive index, classical analog of electromagnetically-induced transparency, and extraordinary transmission. Among MMs, MM perfect absorbers (MMPAs), which are useful to enhance the efficiency in capturing solar energy and applied to various application areas, have been rapidly developed. In general, the structure of MMPAs is very simple, which consist of three layers: patterned conductor layer, which is used for minimizing the reflection by impedance matching, dielectric layer and continuous conductor layer for blocking the transmission. In addition, the unit-cell size of general MM absorbers is only 1/3-1/5 of the working wavelength of incident electromagnetic wave. Nevertheless, the properties of general MMPAs are in problems of the absorption only at specific frequency, the narrow absorption band, the polarization sensitivity and so on. In this review paper, the introduction of recent researches in the field of MMPAs operating in different frequency ranges is presented. Moreover, the researches on the improved electromagnetic properties are discussed, which comprise multi-band, broadband, tunable, polarization-insensitive, and wide-incident-angle MMPAs. The perspectives and the future works for the further investigations and the various real applications of MMPAs are also presented.

  13. Scattering of Electromagnetic Waves by Drift Vortex in Plasma

    Institute of Scientific and Technical Information of China (English)

    WANG Dong; CHEN Yinhua; WANG Ge

    2008-01-01

    In a quasi-two-dimensional model, the scattering of incident ordinary electromag-netic 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 (kia << 1), it is found that the angle at which the scattering cross-section reaches its maxim depends significantly on the approxi-mation 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 ki<< 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.

  14. Influence of electromagnetic SHF-waves on motility of tubifex

    Directory of Open Access Journals (Sweden)

    I. K. Smolyarenko

    2005-02-01

    Full Text Available We investigated influence of electromagnetic superhigh frequency (SHF waves (10 hHz on mechanical parameters of motility of bunch tubifex (1300 - 1500 units at a different load and sequence of its mechanical stimulation. Is shown, that after a пот-thermal waveirradiation (1 MVt/sm2 latency and forward front of mechanograms is increased on 5 - 10 %, amplitude and duration of the answers simultaneously decreases. The maximal mass, which can lift single unit tubifex is decreased. The capacity of single unit is reduced on the average about 80 %. The authors make conclusion about temporary negative influence SHF-waves on simple biological systems.

  15. Analytical Study of Electromagnetic Wave in Superlattice

    Institute of Scientific and Technical Information of China (English)

    LINChang; ZHANGXiu-Lian

    2004-01-01

    The theoretical description of soliton solutions and exact analytical solutions in the sine-Gordon equation is extended to superlattice physics. A family of interesting exact solutions and a new exact analytical solution have been obtained for the electromagnetic wave propagating through a superlattice. In more general cases, the vector potential along the propagating direction obeys the sine-Gordon equation. Some mathematical results of theoretical investigation are given for different cases in supedattices.

  16. Analytical Study of Electromagnetic Wave in Superlattice

    Institute of Scientific and Technical Information of China (English)

    LIN Chang; ZHANG Xiu-Lian

    2004-01-01

    The theoretical description of soliton solutions and exact analytical solutions in the sine-Gordon equation is extended to superlattice physics. A family of interesting exact solutions and a new exact analytical solution have been obtained for the electromagnetic wave propagating through a superlattice. In more general cases, the vector potential along the propagating direction obeys the sine-Gordon equation. Some mathematical results of theoretical investigation are given for different cases in superlattices.

  17. Electromagnetic Components of Auroral Hiss and Lower Hybrid Waves in the Polar Magnetosphere

    Science.gov (United States)

    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.

  18. Electromagnetic Waves in a Uniform Gravitational Field and Planck's Postulate

    CERN Document Server

    Acedo, L

    2015-01-01

    The gravitational redshift forms the central part of the majority of the classical tests for the general theory of relativity. It could be successfully checked even in laboratory experiments on the earth's surface. The standard derivation of this effect is based on the distortion of the local structure of spacetime induced by large masses. The resulting gravitational time-dilation near these masses gives rise to a frequency change of any periodic process, including electromagnetic oscillations as the wave propagates across the gravitational field. This phenomenon can be tackled with classical electrodynamics assuming a curved spacetime background and Maxwell's equations in a generally covariant form. In the present paper, we show that in a classical field-theoretical context the gravitational redshift can be interpreted as the propagation of electromagnetic waves in a medium with corresponding conductivity $\\sigma=g/(\\mu_0 c^3)$, where $g$ is the gravitational acceleration and $\\mu_0$ is the vacuum magnetic p...

  19. Storage of Electromagnetic Waves in a Metamaterial that Mimics Electromagnetically Induced Transparency

    CERN Document Server

    Nakanishi, Toshihiro; Tamayama, Yasuhiro; Kitano, Masao

    2013-01-01

    We propose a method for dynamically controlling the properties of a metamaterial that mimics electromagnetically induced transparency (EIT) by introducing varactor diodes to manipulate the structural symmetry of the metamaterial. Dynamic modulation of the EIT property enables the storage and retrieval of electromagnetic waves. We confirmed that the electromagnetic waves were stored and released, while maintaining the phase distribution in the propagating direction.

  20. Fermi energy-dependence of electromagnetic wave absorption in graphene

    Science.gov (United States)

    Shoufie Ukhtary, M.; Hasdeo, Eddwi H.; Nugraha, Ahmad R. T.; Saito, Riichiro

    2015-05-01

    Undoped graphene is known to absorb 2.3% of visible light at a normal angle of incidence. In this paper, we theoretically demonstrate that the absorption of 10-100 GHz of an electromagnetic wave can be tuned from nearly 0 to 100% by varying the Fermi energy of graphene when the angle of incidence of the electromagnetic wave is kept within total internal reflection geometry. We calculate the absorption probability of the electromagnetic wave as a function of the Fermi energy of graphene and the angle of incidence of the wave. These results open up possibilities for the development of simple electromagnetic wave-switching devices operated by gate voltage.

  1. Electromagnetic Fields and Waves in Fractional Dimensional Space

    CERN Document Server

    Zubair, Muhammad; Naqvi, Qaisar Abbas

    2012-01-01

    This book presents the concept of fractional dimensional space applied to the use of electromagnetic fields and waves. It provides demonstrates the advantages in studying the behavior of electromagnetic fields and waves in fractal media. The book presents novel fractional space generalization of the differential electromagnetic equations is provided as well as a new form of vector differential operators is formulated in fractional space. Using these modified vector differential operators, the classical Maxwell's electromagnetic equations are worked out. The Laplace's, Poisson's and Helmholtz's

  2. Bio-Soliton Model that predicts Non-Thermal Electromagnetic Radiation Frequency Bands, that either Stabilize or Destabilize Life Conditions

    CERN Document Server

    Geesink, J H

    2016-01-01

    Solitons, as self-reinforcing solitary waves, interact with complex biological phenomena such as cellular self-organisation. Soliton models are able to describe a spectrum of electromagnetism modalities that can be applied to understand the physical principles of biological effects in living cells, as caused by electromagnetic radiation. A bio-soliton model is proposed, that enables to predict which eigen-frequencies of non-thermal electromagnetic waves are life-sustaining and which are, in contrast, detrimental for living cells. The particular effects are exerted by a range of electromagnetic wave frequencies of one-tenth of a Hertz till Peta Hertz, that show a pattern of twelve bands, if positioned on an acoustic frequency scale. The model was substantiated by a meta-analysis of 240 published papers of biological radiation experiments, in which a spectrum of non-thermal electromagnetic waves were exposed to living cells and intact organisms. These data support the concept of coherent quantized electromagnet...

  3. Quick finite elements for electromagnetic waves

    CERN Document Server

    Pelosi, Giuseppe; Selleri, Stefano

    2009-01-01

    This practical book and accompanying software enables you to quickly and easily work out challenging microwave engineering and high-frequency electromagnetic problems using the finite element method (FEM) Using clear, concise text and dozens of real-world application examples, the book provides a detailed description of FEM implementation, while the software provides the code and tools needed to solve the three major types of EM problems: guided propagation, scattering, and radiation.

  4. The specific absorption rate of tissues in rats exposed to electromagnetic plane waves in the frequency range of 0.05-5 GHz and SARwb in free-moving rats.

    Science.gov (United States)

    Chen, Bingxin; Wang, Jiamin; Qi, Hongxin; Zhang, Jie; Chen, Shude; Wang, Xianghui

    2017-03-01

    As electromagnetic exposure experiments can only be performed on small animals, usually rats, research on the characteristics of specific absorption rate (SAR) distribution in the rat has received increasing interest. A series of calculations, which simulated the SAR in a male rat anatomical model exposed to electromagnetic plane waves ranging from 0.05 to 5 GHz with different incidence and polarization, were conducted. The whole-body-averaged SAR (SARwb) and the tissue-averaged SAR (SARavg) in 20 major tissues were determined. Results revealed that incidence has great impact on SAR in the rat at higher frequencies owing to the skin effect and the effect on SARavg in tissues is much more apparent than that on SARwb; while polarization plays an important role under lower frequencies. Not only the incidence, but also the polarization in the rat keeps changing when the rat is in free movement. Thus, this article discussed a convenient way to obtain relatively accurate SARwb in a free-moving rat.

  5. Electromagnetic waves destabilized by runaway electrons in near-critical electric fields

    CERN Document Server

    Kómár, A; Fülöp, T

    2013-01-01

    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.

  6. Understanding possible electromagnetic counterparts to loud gravitational wave events: Binary black hole effects on electromagnetic fields

    CERN Document Server

    Palenzuela, Carlos; Yoshida, Shin

    2009-01-01

    In addition to producing loud gravitational waves (GW), the dynamics of a binary black hole system could induce emission of electromagnetic (EM) radiation by affecting the behavior of plasmas and electromagnetic fields in their vicinity. We here 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.

  7. Frequency hopping millimeter wave reflectometer

    Science.gov (United States)

    Cupido, L.; Sánchez, J.; Estrada, T.

    2004-10-01

    Reflectometry techniques are employed to study density fluctuations in fusion plasmas either using one channel or two channels with slightly different frequencies, to probe simultaneously closely spaced plasma layers (for radial correlation studies). The present article describes a novel system with increasing measuring capability utilizing only one single frequency that can be hopped during the discharge. This broadband fast hopping mm-wave reflectometer (BFHR) has been developed for both ASDEX upgrade (Max Plank Institute-Garching-Germany) and TJ-II stellarator (CIEMAT-Spain). The BFHR incorporates frequency synthesizers at microwave frequencies multiplied into the millimeter-wave range and uses heterodyne detection for sensitive phase and amplitude measurements.

  8. Do electromagnetic waves always propagate along null geodesics?

    CERN Document Server

    Asenjo, Felipe A

    2016-01-01

    We find exact solutions to Maxwell equations written in terms of four-vector potentials in non--rotating, as well as in G\\"odel and Kerr spacetimes. Exact electromagnetic waves solutions are written on given gravitational field backgrounds where they evolve. We find that in non--rotating spherical symmetric spacetimes, electromagnetic plane waves travel along null geodesics. However, electromagnetic plane waves on G\\"odel and Kerr spacetimes do not exhibit that behavior.

  9. Stable Propagating Waves and Wake Fields in Relativistic Electromagnetic Plasma

    Institute of Scientific and Technical Information of China (English)

    DUAN Yi-Shi; XIE Bai-Song; TIAN Miao; YIN Xin-Tao; ZHANG Xin-Hui

    2008-01-01

    Stable propagating waves and wake fields in relativistic electromagnetic plasma are investigated. The incident electromagnetic field has a finite initial constant amplitude meanwhile the longitudinal momentum of electrons is taken into account in the problem. It is found that in the moving frame with transverse wave group velocity the stable propagating transverse electromagnetic waves and longitudinal plasma wake fields can exist in the appropriate regime of plasma.

  10. Three-wave mixing of ordinary and backward electromagnetic waves: extraordinary transients in the nonlinear reflectivity and parametric amplification.

    Science.gov (United States)

    Slabko, Vitaly V; Popov, Alexander K; Tkachenko, Viktor A; Myslivets, Sergey A

    2016-09-01

    Three-wave mixing of ordinary and backward electromagnetic waves in a pulsed regime is investigated in the metamaterials that enable the coexistence and phase-matching of such waves. It is shown that the opposite direction of phase velocity and energy flux in backward waves gives rise to extraordinary transient processes due to greatly enhanced optical parametric amplification and frequency up- and down-shifting nonlinear reflectivity. The differences are illustrated through comparison with the counterparts in ordinary, co-propagating settings.

  11. Simulation study of localization of electromagnetic waves in two-dimensional random dipolar systems.

    Science.gov (United States)

    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.

  12. Instantaneous polarization statistics of electromagnetic waves

    Institute of Scientific and Technical Information of China (English)

    WANG Xuesong; LI Yongzhen; DAI Dahai; XIAO Shunping; ZHUANG Zhaowen

    2004-01-01

    The problem of statistical description of instantaneous polarization of electromagnetic waves is studied. First, the physical meanings of instantaneous Stokes vectors' components are analyzed, which provide a short cut for solving statistical distribution functions of instantaneous Stokes vectors. Second, in the condition of Gaussian hypothesis, the analytical expressions of probability density function (PDF) of instantaneous Stokes vectors are presented. Finally, some computation results are presented in the condition of two independent polarization channels, which show the validity and simplicity of the statistical description method.

  13. Selective generation of ultrasonic Lamb waves by electromagnetic acoustic transducers

    Science.gov (United States)

    Li, Ming-Liang; Deng, Ming-Xi; Gao, Guang-Jian

    2016-12-01

    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. Project supported by the National Natural Science Foundation of China (Grant Nos. 11474361 and 11274388).

  14. Simultaneous observation of gravitational and electromagnetic waves

    CERN Document Server

    Branchina, Vincenzo

    2016-01-01

    Assuming that the short gamma-ray burst detected by the Fermi Gamma-Ray Space Telescope about 0.4 seconds after the gravitational waves observed by the LIGO and VIRGO Collaborations originated from the same black hole merger event, we perform a model-independent analysis of different quantum gravity scenarios based on (modified) dispersion relations (typical of quantum gravity models) for the graviton and the photon. We find that only scenarios where at least one of the two particles is luminal (the other being sub- or super-luminal) are allowed, while scenarios where none of the two particles is luminal are ruled out. Moreover, the physical request of having acceptable values for the quantum gravity scale imposes stringent bounds on the difference between the velocities of electromagnetic and gravitational waves, much more stringent than any previously known bound.

  15. Ring Current-Electromagnetic Ion Cyclotron Waves Coupling

    Science.gov (United States)

    Khazanov, G. V.

    2005-01-01

    The effect of Electromagnetic Ion Cyclotron (EMIC) waves, generated by ion temperature anisotropy in Earth s ring current (RC), is the best known example of wave- particle interaction in the magnetosphere. Also, there is much controversy over the importance of EMIC waves on RC depletion. Under certain conditions, relativistic electrons, with energies 21 MeV, can be removed from the outer radiation belt (RB) by EMIC wave scattering during a magnetic storm. That is why the calculation of EMIC waves must be a very critical part of the space weather studies. The new RC model that we have developed and present for the first time has several new features that we have combine together in a one single model: (a) several lower frequency cold plasma wave modes are taken into account; (b) wave tracing of these wave has been incorporated in the energy EMIC wave equation; (c) no assumptions regarding wave shape spectra have been made; (d) no assumptions regarding the shape of particle distribution have been made to calculate the growth rate; (e) pitch-angle, energy, and mix diffusions are taken into account together for the first time; (f) the exact loss-cone RC analytical solution has been found and coupled with bounce-averaged numerical solution of kinetic equation; (g) the EMIC waves saturation due to their modulation instability and LHW generation are included as an additional factor that contributes to this process; and (h) the hot ions were included in the real part of dielectric permittivity tensor. We compare our theoretical results with the different EMIC waves models as well as RC experimental data.

  16. Broadband unidirectional behavior of electromagnetic waves based on transformation optics

    Science.gov (United States)

    Zang, Xiaofei; Zhu, Yiming; Ji, Xuebin; Chen, Lin; Hu, Qing; Zhuang, Songlin

    2017-01-01

    High directive antennas are fundamental elements for microwave communication and information processing. Here, inspired by the method of transformation optics, we propose and demonstrate a transformation medium to control the transmission path of a point source, resulting in the unidirectional behavior of electromagnetic waves (directional emitter) without any reflectors. The network of inductor-capacitor transmission lines is designed to experimentally realize the transformation medium. Furthermore, the designed device can work in a broadband frequency range. The unidirectional-manner-based device demonstrated in this work will be an important step forward in developing a new type of directive antennas.

  17. Robust imaging with electromagnetic waves in noisy environments

    Science.gov (United States)

    Borcea, Liliana; Garnier, Josselin

    2016-10-01

    We study imaging with an array of sensors that probes a medium with single frequency electromagnetic waves and records the scattered electric field. The medium is known and homogenous except for some small and penetrable inclusions. The goal of inversion is to locate and characterize these inclusions from the data collected by the array, which are corrupted by additive noise. We use results from random matrix theory to obtain a robust inversion method. We assess its performance with numerical simulations and quantify the benefit of measuring more than one component of the scattered electric field.

  18. Properties of electrons scattered by a strong plane electromagnetic wave with a linear polarization: Semiclassical treatment

    Science.gov (United States)

    Bogdanov, O. V.; Kazinski, P. O.

    2015-02-01

    The problem of scattering of ultrarelativistic electrons by a strong plane electromagnetic wave of a low (optical) frequency and linear polarization is solved in the semiclassical approximation, when the electron wave packet size is much smaller than the wavelength of electromagnetic wave. The exit momenta of ultrarelativistic electrons scattered are found using the exact solutions to the equations of motion with radiation reaction included (the Landau-Lifshitz equation). It is found that the momentum components of electrons traversed the electromagnetic wave depend weakly on the initial values of momenta. These electrons are mostly scattered at small angles to the propagation direction of the electromagnetic wave. The maximum Lorentz factor of electrons crossed the electromagnetic wave is proportional to the work done by the electromagnetic field and is independent of the initial momentum. The momentum component parallel to the electric field vector of the electromagnetic wave is determined solely by the laser beam diameter measured in the units of the classical electron radius. As for the reflected electrons, they for the most part lose the energy, but remain relativistic. A reflection law that relates the incident and reflection angles and is independent of any parameters is found.

  19. Electromagnetic Counterparts of Gravitational Wave Sources : Mergers of Compact Objects

    CERN Document Server

    Kamble, Atish

    2016-01-01

    Mergers of compact objects are considered prime sources of gravitational waves (GW) and will soon be targets of GW observatories such as the Advanced-LIGO, VIRGO etc. Finding electromagnetic counterparts of these GW sources will be important to understand their nature. We discuss possible electromagnetic signatures of the mergers. We show that the BH-BH mergers could have luminosities which exceed Eddington luminosity from unity to several orders of magnitude depending on the masses of the merging BHs. As a result these mergers could be explosive, release up to $10^{51}$ erg of energy and shine as radio transients. At any given time we expect about a few such transients in the sky at GHz frequencies which could be detected out to about 300 Mpc. It has also been argued that these radio transients would look alike radio supernovae with comparable detection rates. Multi-band follow up could, however, distinguish between the mergers and supernovae.

  20. Interface Polarization Strategy to Solve Electromagnetic Wave Interference Issue.

    Science.gov (United States)

    Lv, Hualiang; Guo, Yuhang; Wu, Guanglei; Ji, Guangbin; Zhao, Yue; Xu, Zhichuan J

    2017-02-15

    Design of an interface to arouse interface polarization is an efficient route to attenuate high-frequency electromagnetic waves. The attenuation intensity is highly related to the contact area. To achieve stronger interface polarization, growing metal oxide granular film on graphene with a larger surface area seems to be an efficient strategy due to the high charge carrier concentration of graphene. This study is devoted to fabricating the filmlike composite by a facile thermal decomposition method and investigating the relationship among contact area, polarization intensity, and the type of metal oxide. Because of the high-frequency polarization effect, the composites presented excellent electromagnetic wave attenuation ability. It is shown that the optimal effective frequency bandwidth of graphene/metal oxide was close to 7.0 GHz at a thin coating layer of 2.0 mm. The corresponding reflection loss value was nearly -22.1 dB. Considering the attenuation mechanism, interface polarization may play a key role in the microwave-absorbing ability.

  1. Alterations in Adenylate Kinase Activity in Human PBMCs after In Vitro Exposure to Electromagnetic Field: Comparison between Extremely Low Frequency Electromagnetic Field (ELF) and Therapeutic Application of a Musically Modulated Electromagnetic Field (TAMMEF)

    OpenAIRE

    Antonietta Albanese; Emilio Battisti; Daniela Vannoni; Emilia Aceto; Gianmichele Galassi; Stefania Giglioni; Valentina Tommassini; Nicola Giordano

    2009-01-01

    This study investigated the effects of electromagnetic fields on enzymes involved in purine metabolism in human peripheral blood mononuclear cells in vitro. Cells were obtained from 20 volunteers. We tested both low-energy, extremely low frequency (ELF; 100-Hz) electromagnetic fields and the Therapeutic Application of Musically Modulated Electromagnetic Fields (TAMMEFs); the latter is characterized by variable frequencies, intensities, and wave shapes. Adenylate kinase activity was increas...

  2. Electromagnetic Waves Broadcast by a VCR.

    Science.gov (United States)

    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)

  3. Interaction of fast ions with ion cyclotron electromagnetic waves in tokamak plasma; Interaction des ions rapides avec les ondes a la frequence cyclotronique ionique dans un plasma de tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Bergeaud, V

    2000-12-01

    In an ignited fusion reactor, the plasma temperature is sustained by the fusion reactions. However, before this regime is reached, it is necessary to bring an additional power to the plasma. One of the methods that enables the coupling of power is the use of an electromagnetic wave in the ion cyclotron range of frequencies (ICRF). This thesis deals with the interaction between ICRF heating and the fast ions. The thesis contains a theoretical study of the influence of ICRF heating on the ion distribution function. A particular emphasis is put on the importance of the toroidal spectrum of the modes of propagation of the wave in the tokamak. It is necessary to take into account all these modes in order to correctly assess the strength of the wave particle interaction, especially for high energy particles (of the order of hundreds of keV). The classical treatment of the wave particle interaction is based on the hypothesis that the cyclotron phase of the particle and the wave phase are de-correlated between successive resonant interactions. One is therefore led to consider ICRF heating as a diffusive process. This hypothesis is reconsidered in this thesis and it is shown that strong correlations exist in a large part of the velocity space. For this study, a numerical code that computes the full trajectory of particles interacting with a complete electromagnetic field has been developed. The thesis also deals with the problem of fast ion losses due to the breaking of the toroidal symmetry of the confinement magnetic field (called the ripple modulation). Between two toroidal coils, local magnetic wells exist, and particles can be trapped there. When trapped they undergo a vertical drift that makes them quit the plasma rapidly. The ripple modulation also causes an enhancement of the radial diffusion, thereby increasing the losses. A Monte Carlo model describing these mechanisms is presented. This model is validated thanks to a comparison with an experimental database from

  4. Implementation of electromagnetically induced transparency in a metamaterial controlled with auxiliary waves

    CERN Document Server

    Nakanishi, Toshihiro

    2015-01-01

    We propose a metamaterial to realize true electromagnetically induced transparency (EIT), where the incidence of an auxiliary electromagnetic wave called the control wave induces transparency for a probe wave. The analogy to the original EIT effect in an atomic medium is shown through analytical and numerical calculations derived from a circuit model for the metamaterial. We performed experiments to demonstrate the EIT effect of the metamaterial in the microwave region. The width and position of the transparent region can be controlled by the power and frequency of the control wave. We also observed asymmetric transmission spectra unique to the Fano resonance.

  5. 电磁导波激励脉冲群最佳重复频率确定%Determination on repetition frequency of electromagnetic guided wave excited by impulse cluster

    Institute of Scientific and Technical Information of China (English)

    孙钦蕾; 刘美全; 周海林

    2012-01-01

    电磁导波检测技术因其非接触耦合的特性已被广泛应用于各种金属管道无损检测领域中。但导波的激励脉冲群重复频率的确定长久以来却没有一个有效的解决方法。为此,本文提出了以有、无缺陷的重复脉冲群检测信号的相关性作为判别标准,选取电磁导波激励脉冲群最佳重复频率,并从检测信号特征提取和识别的角度验证了本文选取的激励脉冲群最佳重复频率可有效提高导波检测信号之间的区分度,减小检测信号间的干扰,提高缺陷识别的准确性。%As a result of contactless coupling, electromagnetic guided wave detection technology is used extensively to detect various metallic pipelines, however, it hasn't achieved an effective solution about reception frequency of guided wave exciting impulse cluster. So, in this paper, the correlation between flaw detection signal from repetition impulse cluster and no defect is proposed as criterion to choose optimal repetition frequency of exciting impulse cluster, through feature extraction and identification of testing signal, which is prove that it can improve efficiently discrimination degree of guided wave signals, decrease noise jamming, and advance precision of defect identification.

  6. Surface waves propagation on a turbulent flow forced electromagnetically

    CERN Document Server

    Gutiérrez, Pablo

    2015-01-01

    We study the propagation of monochromatic surface waves on a turbulent flow. The flow is generated in a layer of liquid metal by an electromagnetic forcing. This forcing creates a quasi two-dimensional (2D) turbulence with strong vertical vorticity. The turbulent flow contains much more energy than the surface waves. In order to focus on the surface wave, the deformations induced by the turbulent flow are removed. This is done by performing a coherent phase averaging. For wavelengths smaller than the forcing lengthscale, we observe a significant increase of the wavelength of the propagating wave that has not been reported before. We suggest that it can be explained by the random deflection of the wave induced by the velocity gradient of the turbulent flow. Under this assumption, the wavelength shift is an estimate of the fluctuations of deflection angle. The local measurements of the wave frequency far from the wavemaker do not reveal such systematic behavior, although a small shift is measured. Finally we qu...

  7. The plane wave spectrum representation of electromagnetic fields

    CERN Document Server

    Clemmow, P C

    1966-01-01

    The Plane Wave Spectrum Representation of Electromagnetic Fields presents the theory of the electromagnetic field with emphasis to the plane wave. This book explains how fundamental electromagnetic fields can be represented by the superstition of plane waves traveling in different directions. Organized into two parts encompassing eight chapters, this book starts with an overview of the methods whereby plane wave spectrum representation can be used in attacking different characteristic problems belonging to the theories of radiation, diffraction, and propagation. This book then discusses the co

  8. Study of dense-plasma properties using very high-frequency electromagnetic waves (light waves); Etude des proprietes des plasmas denses au moyen d'ondes electromagnetiques de tres haute frequence (ondes lumineuses)

    Energy Technology Data Exchange (ETDEWEB)

    Gormezano, C. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1967-07-01

    A study is made of methods based on the use of lasers for measuring the electronic density and temperature of dense plasmas (N{sub e} > 10{sup 15}e/cm{sup 3}): - an interferometric method using a gas laser, based on the. properties of the Perot-Fabry cavities; - a method making use of the 90 deg C scattering produced by the plasma on light emitted by a ruby laser. These methods have been applied to various dense plasmas: - high-frequency plasma torch; - azimuth compression; - plasma bursts produced by focussing a laser beam on a metal target. The measurements have also been carried out using conventional methods of diagnosis. It has thus been possible to measure densities of between 5.10{sup 15} and 10{sup 19} e/cm{sup 3} and temperatures of between 3 and 10 eV. These different-methods are then compared, (author) [French] On etudie la mesure de la densite et de la temperature electronique des plasmas denses (N{sub e} > 10{sup 15} e/cm{sup 3}) a I'aide de methodes utilisant des lasers: - une methode interferometrique utilisant un laser a gaz, basee sur les proprietes des cavites Perot Fabry; -- une methode utilisant la diffusion a 900 deg C par le plasma de la lumiere issue d'un laser a rubis. Ces methodes ont ete appliquees sur differents plasmas denses: - Torche a plasma haute-frequence; - Compression azimutale; - Bouffees de plasma produites par la focalisation d'un faisceau laser sur une cible metallique. Les mesures ont ete egalement faites a I'aide de diagnostics classiques. On a pu ainsi mesurer des densites comprises entre 5.10{sup 15} et 10{sup 19} e/cm{sup 3} et des temperatures comprises entre 3 et 10 eV. On compare ensuite ces differentes methodes. (auteur)

  9. Excitation threshold of Stimulated Electromagnetic Emissions SEEs generated at pump frequency near the third electron gyroharmonic

    Science.gov (United States)

    Mahmoudian, A.; Bernhardt, P. A.; Scales, W.

    2012-12-01

    The High-Frequency Active Auroral Research Program (HAARP) in Gakona, Alaska provides effective radiated powers in the megawatt range that have allowed researchers to study many non-linear effects of wave-plasma interactions. Stimulated Electromagnetic Emission (SEE) is of interest to the ionospheric community for its diagnostic purposes. In recent HAARP heating experiments, it has been shown that during the Magnetized Stimulated Brillouin Scattering MSBS instability, the pumped electromagnetic wave may decay into an electromagnetic wave and a low frequency electrostatic wave (either ion acoustic IA wave or electrostatic ion cyclotron EIC wave). Using Stimulated Electromagnetic Emission (SEE) spectral features, side bands which extend above and below the pump frequency can yield significant diagnostics for the modified ionosphere. It has been shown that the IA wave frequency offsets can be used to measure electron temperature in the heated ionosphere and EIC wave offsets can be used as a sensitive method to determine the ion species by measuring ion mass using the ion gyro-frequency offset. The threshold of each emission line has been measured by changing the amplitude of pump wave. The experimental results aimed to show the threshold for transmitter power to excite IA wave propagating along the magnetic field lines as well as for EIC wave excited at an oblique angle relative to the background magnetic field. Another parametric decay instability studied is the ion Bernstein decay instability that has been attributed to the simultaneous parametric decay of electron Bernstein waves into multiple electron Bernstein and ion Bernstein waves. The SIB process is thought to involve mode conversion from EM to EB waves followed by parametric decay of the EB wave to multiple EB and IB waves. The parametric decay instability of ion Bernstein modes has been observed simultaneously for the first time at the third electron gyroharmonics during 2011 Summer Student Research

  10. Effects of Extremely Low Frequency Electromagnetic Fields on Growth and Differentiation of ’Physarum polycephalum’

    Science.gov (United States)

    1975-04-01

    AD-AO10 187 EFFECTS OF EXTREMELY LOW FREQUENCY ELECTRO- MAGNETIC FIELDS ON GROWTH AND DIFFERENTIATION OF ’ PHYSARUM POLYCEPHALUM ’ E. M. Guodman, et al...LExtremely Low Prequency Electromagnetic Fields on Growth and Differentiation of Physarum polycephalum Technical Report Phase I (Continuous Wave) by...that weak, alternating electromagnetic fields (60 or 75 Hz, 2.0 G, 0.7 V/n) affect the cell cycle of Physarum polycephalum by increasing the interval

  11. Modulational instability of electromagnetic waves in a collisional quantum magnetoplasma

    Energy Technology Data Exchange (ETDEWEB)

    Niknam, A. R., E-mail: a-niknam@sbu.ac.ir [Laser and Plasma Research Institute, Shahid Beheshti University, G.C., Tehran (Iran, Islamic Republic of); Rastbood, E.; Bafandeh, F.; Khorashadizadeh, S. M., E-mail: smkhorashadi@birjand.ac.ir [Physics Department of Birjand University, Birjand (Iran, Islamic Republic of)

    2014-04-15

    The modulational instability of right-hand circularly polarized electromagnetic electron cyclotron (CPEM-EC) wave in a magnetized quantum plasma is studied taking into account the collisional effects. Employing quantum hydrodynamic and nonlinear Schrödinger equations, the dispersion relation of modulated CPEM-EC wave in a collisional plasma has been derived. It is found that this wave is unstable in such a plasma system and the growth rate of the associated instability depends on various parameters such as electron Fermi temperature, plasma number density, collision frequency, and modulation wavenumber. It is shown that while the increase of collision frequency leads to increase of the growth rate of instability, especially at large wavenumber limit, the increase of plasma number density results in more stable modulated CPEM-EC wave. It is also found that in contrast to collisionless plasma in which modulational instability is restricted to small wavenumbers, in collisional plasma, the interval of instability occurrence can be extended to a large domain.

  12. Spatial transformation-enabled electromagnetic devices: from radio frequencies to optical wavelengths.

    Science.gov (United States)

    Jiang, Zhi Hao; Turpin, Jeremy P; Morgan, Kennith; Lu, Bingqian; Werner, Douglas H

    2015-08-28

    Transformation optics provides scientists and engineers with a new powerful design paradigm to manipulate the flow of electromagnetic waves in a user-defined manner and with unprecedented flexibility, by controlling the spatial distribution of the electromagnetic properties of a medium. Using this approach, over the past decade, various previously undiscovered physical wave phenomena have been revealed and novel electromagnetic devices have been demonstrated throughout the electromagnetic spectrum. In this paper, we present versatile theoretical and experimental investigations on designing transformation optics-enabled devices for shaping electromagnetic wave radiation and guidance, at both radio frequencies and optical wavelengths. Different from conventional coordinate transformations, more advanced and versatile coordinate transformations are exploited here to benefit diverse applications, thereby providing expanded design flexibility, enhanced device performance, as well as reduced implementation complexity. These design examples demonstrate the comprehensive capability of transformation optics in controlling electromagnetic waves, while the associated novel devices will open up new paths towards future integrated electromagnetic component synthesis and design, from microwave to optical spectral regimes. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  13. Quantified Energy Dissipation Rates: Electromagnetic Wave Observations in the Terrestrial Bow Shock

    CERN Document Server

    Wilson, L B; Breneman, A W; Contel, O Le; Cully, C; Turner, D L; Angelopoulos, V

    2013-01-01

    We present the first quantified measure of the rate of energy dissipated per unit volume by high frequency electromagnetic waves in the transition region of the Earth's collisionless bow shock using data from the THEMIS spacecraft. Every THEMIS shock crossing examined with available wave burst data showed both low frequency ( 10 Hz) electromagnetic and electrostatic waves throughout the entire transition region and into the magnetosheath. The waves in both frequency ranges had large amplitudes, but the higher frequency waves, which are the focus of this study, showed larger contributions to both the Poynting flux and the energy dissipation rates. The higher frequency waves were identified as combinations of ion-acoustic waves, electron cyclotron drift instability driven waves, electrostatic solitary waves, and whistler mode waves. These waves were found to have: (1) amplitudes capable of exceeding dB ~ 10 nT and dE ~ 300 mV/m, though more typical values were dB ~ 0.1-1.0 nT and dE ~ 10-50 mV/m; (2) energy flu...

  14. Electromagnetic wave propagation through a slab of a dispersive medium

    CERN Document Server

    Ismail, Mohamed

    2016-01-01

    A method is proposed for the analysis of the propagation of electromagnetic waves through a homogeneous slab of a medium with Drude-Lorentz dispersion behavior, and excited by a causal sinusoidal source. An expression of the time dependent field, free from branch-cuts in the plane of complex frequencies, is established. This method provides the complete temporal response in both the steady-state and transient regimes in terms of discrete poles contributions. The Sommerfeld and Brillouin precursors are retrieved and the corresponding set of poles are identified. In addition, the contribution in the transient field of the resonance frequency in the Drude-Lorentz model is exhybited, and the effect of reflections resulting from the refractive index mismatch at the interfaces of the slab are analyzed.

  15. Electromagnetic wave propagation in a random distribution of C{sub 60} molecules

    Energy Technology Data Exchange (ETDEWEB)

    Moradi, Afshin, E-mail: a.moradi@kut.ac.ir [Department of Engineering Physics, Kermanshah University of Technology, Kermanshah, Iran and Department of Nano Sciences, Institute for Studies in Theoretical Physics and Mathematics (IPM), Tehran (Iran, Islamic Republic of)

    2014-10-15

    Propagation of electromagnetic waves in a random distribution of C{sub 60} molecules are investigated, within the framework of the classical electrodynamics. Electronic excitations over the each C{sub 60} molecule surface are modeled by a spherical layer of electron gas represented by two interacting fluids, which takes into account the different nature of the π and σ electrons. It is found that the present medium supports four modes of electromagnetic waves, where they can be divided into two groups: one group with shorter wavelength than the light waves of the same frequency and the other with longer wavelength than the free-space radiation.

  16. Tunneling properties of electromagnetic wave in slab superconducting material

    Institute of Scientific and Technical Information of China (English)

    Khem B. Thapa; Sanjay Srivastava; Alka Vishwakarma; S. P. Ojha

    2011-01-01

    When the electromagnetic wave propagates through a slab superconducting material in microwave ranges, tunneling properties of the electromagnetic wave at critical temperature are investigated theoretically. The transmittance and the reflectance of the slab superconducting material vary with the thickness of material as well as the refractive index of substrates.The high transmittance is found for thin superconductor at low wavelength region.However, optical properties are strongly dependent upon temperature and incidence wavelength. The electromagnetic wave is totally transmitted without loss for incidence wavelength (λ = 5000 nm) due to the zero refractive index and infinite penetration depth of the superconductor at the critical temperature.

  17. Surface Acoustic Wave Frequency Comb

    CERN Document Server

    Savchenkov, A A; Ilchenko, V S; Seidel, D; Maleki, L

    2011-01-01

    We report on realization of an efficient triply-resonant coupling between two long lived optical modes and a high frequency surface acoustic wave (SAW) mode of the same monolithic crystalline whispering gallery mode resonator. The coupling results in an opto-mechanical oscillation and generation of a monochromatic SAW. A strong nonlinear interaction of this mechanical mode with other equidistant SAW modes leads to mechanical hyper-parametric oscillation and generation of a SAW pulse train and associated frequency comb in the resonator. We visualized the comb observing the modulation of the modulated light escaping the resonator.

  18. Large Amplitude Low Frequency Waves in a Magnetized Nonuniform Electron-Positron-Ion Plasma

    Institute of Scientific and Technical Information of China (English)

    Q. Haque; H. Saleem

    2004-01-01

    @@ It is shown that the large amplitude low-frequency electromagnetic drift waves in electron-positron-ion plasmas might give rise to dipolar vortices. A linear dispersion relation of several coupled electrostatic and electromagnetic low-frequency modes is obtained. The relevance of this work to both laboratory and astrophysical situations is pointed out.

  19. Generation of ordinary mode electromagnetic radiation near the upper hybrid frequency in the magnetosphere

    Science.gov (United States)

    Ashour-Abdalla, M.; Okuda, H.

    1984-01-01

    It is shown by means of plasma numerical simulations that long-wavelength ordinary mode electromagnetic radiation can be generated from short-wavelength electrostatic waves near the upper hybrid resonance frequency in an inhomogeneous plasma. A possible relation of this process to nonthermal continuum radiation in the magnetosphere is discussed.

  20. Localized Electromagnetic Waves: Interactions with Surfaces and Nanostructures

    Science.gov (United States)

    Anderson, Nicholas R.

    The interaction of electromagnetic waves with nanostructures is an important area of research for signal processing devices, magnetic data storage, biosensors and a variety of other applications. In this work, we present analytic and numerical calculations for oscillating electric and magnetic fields coupling with excitations in magnetic materials as well as metallic and dielectric materials, near their resonance frequencies. One of the problems with the miniaturization of signal processing components is that there is a cutoff frequency associated with the transverse electric (TE) mode in waveguides. However, it is usually the TE mode which is used to achieve nonreciprocity for devices such as isolators. As a first step to circumvent this problem we looked at the absorption of electromagnetic waves in an antiferromagnet and a ferrite when the incident wave is at an arbitrary angle with respect to the magnetization direction. We calculated reflectivity and attenuated total reflectivity and found absorption and nonreciprocity, asymmetric behavior for waves traveling in opposite directions, for a broad range of propagation angles. Subsequently we also performed calculations for a transverse magnetic mode in a waveguide. The wave was allowed to propagate at an arbitrary angle with respect to the magnetization direction of the ferrite in the waveguide. We again found nonreciprocity for a wide range of angles. Our results show that this system could be used as an on-chip isolator with isolation values over 75 dB/cm in the 50 GHz range. We explored another signal processing device operating in the GHz range: a nonlinear phase shifter. Using Fe as the magnetic material allows the phase shifter to operate over a wide frequency and power range. We found a differential phase shift of greater than 50° over 3 cm for this device. The theoretical results compared well with experimental measurements. Finally, we study surface plasmon polaritons propagating along a metallic

  1. Numerical study of electromagnetic waves generated by a prototype dielectric logging tool

    Science.gov (United States)

    Ellefsen, K.J.; Abraham, J.D.; Wright, D.L.; Mazzella, A.T.

    2004-01-01

    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 that in the formation (e.g., an air-filled borehole in the unsaturated zone), only a guided wave propagated along the borehole. As the frequency decreased, both the phase and the group velocities of the guided wave asymptotically approached the phase velocity of a plane wave in the formation. The guided wave radiated electromagnetic energy into the formation, causing its amplitude to decrease. When the propagation velocity in the borehole was less than that in the formation (e.g., a water-filled borehole in the saturated zone), both a refracted wave and a guided wave propagated along the borehole. The velocity of the refracted wave equaled the phase velocity of a plane wave in the formation, and the refracted wave preceded the guided wave. As the frequency decreased, both the phase and the group velocities of the guided wave asymptotically approached the phase velocity of a plane wave in the formation. The guided wave did not radiate electromagnetic energy into the formation. To analyze traces recorded by the prototype tool during laboratory tests, they were compared to traces calculated with the finite-difference method. The first parts of both the recorded and the calculated traces were similar, indicating that guided and refracted waves indeed propagated along the prototype tool. ?? 2004 Society of Exploration Geophysicists. All rights reserved.

  2. Scattering of electromagnetic wave by dielectric cylinder in eikonal approximation

    Science.gov (United States)

    Syshchenko, V. V.

    2016-07-01

    The scattering of the plane electromagnetic wave on a spatially extended, fiber lake target is considered. The formula for the scattering cross section is obtained using the approximation analogous to eikonal one in quantum mechanics.

  3. Electromagnetic backscattering from one-dimensional drifting fractal sea surface I: Wave-current coupled model

    Science.gov (United States)

    Tao, Xie; Shang-Zhuo, Zhao; William, Perrie; He, Fang; Wen-Jin, Yu; Yi-Jun, He

    2016-06-01

    To study the electromagnetic backscattering from a one-dimensional drifting fractal sea surface, a fractal sea surface wave-current model is derived, based on the mechanism of wave-current interactions. The numerical results show the effect of the ocean current on the wave. Wave amplitude decreases, wavelength and kurtosis of wave height increase, spectrum intensity decreases and shifts towards lower frequencies when the current occurs parallel to the direction of the ocean wave. By comparison, wave amplitude increases, wavelength and kurtosis of wave height decrease, spectrum intensity increases and shifts towards higher frequencies if the current is in the opposite direction to the direction of ocean wave. The wave-current interaction effect of the ocean current is much stronger than that of the nonlinear wave-wave interaction. The kurtosis of the nonlinear fractal ocean surface is larger than that of linear fractal ocean surface. The effect of the current on skewness of the probability distribution function is negligible. Therefore, the ocean wave spectrum is notably changed by the surface current and the change should be detectable in the electromagnetic backscattering signal. Project supported by the National Natural Science Foundation of China (Grant No. 41276187), the Global Change Research Program of China (Grant No. 2015CB953901), the Priority Academic Development Program of Jiangsu Higher Education Institutions (PAPD), Program for the Innovation Research and Entrepreneurship Team in Jiangsu Province, China, the Canadian Program on Energy Research and Development, and the Canadian World Class Tanker Safety Service.

  4. Electromagnetic Waves and Bursty Electron Acceleration: Implications from Freja

    Science.gov (United States)

    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.

  5. The triggering of electromagnetic observations by gravitational wave events

    OpenAIRE

    Sylvestre, Julien

    2003-01-01

    The prospects for the observation of electromagnetic emissions by gravitational wave sources first detected using a network of interferometers are discussed. Various emission mechanisms and detection techniques for compact binary inspirals are studied to show that the pointing ability of gravitational wave observatories and the efficacy of electromagnetic detectors can be combined to predict that counterpart detections are improbable for the Initial interferometers, possible with Advanced LIG...

  6. Resonant circuit which provides dual frequency excitation for rapid cycling of an electromagnet

    Science.gov (United States)

    Praeg, Walter F.

    1984-01-01

    Disclosed is a ring magnet control circuit that permits synchrotron repetition rates much higher than the frequency of the cosinusoidal guide field of the ring magnet during particle acceleration. the control circuit generates cosinusoidal excitation currents of different frequencies in the half waves. During radio frequency acceleration of the particles in the synchrotron, the control circuit operates with a lower frequency cosine wave and thereafter the electromagnets are reset with a higher frequency half cosine wave. Flat-bottom and flat-top wave shaping circuits maintain the magnetic guide field in a relatively time-invariant mode during times when the particles are being injected into the ring magnets and when the particles are being ejected from the ring magnets.

  7. High-Performance Computational Electromagnetics in Frequency-Domain and Time-Domain

    Science.gov (United States)

    2015-03-04

    aforementioned contributions, for a given 1In view of its applications to seismic wave propagation Dr. Amlani’s PhD thesis received two awards at Cal- tech, one...for wave scattering problems. PhD thesis, California Institute of Technol- ogy, 2014. Available at http://www.its.caltech.edu/~obruno/preprints...solutions for some of the most challenging scattering problems in science and engineering. Electromagnetic scattering . Frequency domain solvers. Integral

  8. TO THE QUESTION OF THE SPEED OF WAVE PROPAGATION IN ELECTROMAGNETIC ENVIRONMENT

    Directory of Open Access Journals (Sweden)

    Alexandrov B. L.

    2016-01-01

    Full Text Available This question is about the speed of wave propagation in electromagnetic environment. Electromagnetic environment (field is the space that fills the whole Universe, occupied by the electromagnetic particles-photons. At the heart of the special relativity theory, the constancy of the speed of light in vacuum is affirmed. According to modern concepts, the speed of light in vacuum is the maximum speed of the particle motion and propagation of interactions. However, light is the narrow range of electromagnetic radiation – (4÷8·1014 Hz, therefore experimentally measured speed of light is referred to this frequency range. The fact that this speed of electromagnetic waves can theoretically be non permanent – physicists have pondered for a long time and this question is periodically excited in the scientific literature. The author of this article also had an impression that the speed of light, in which he understands distribution speed of waves of a wide range of frequencies in the electromagnetic environment, is not a constant. The article attempts to prove it. Many photons of different frequencies move simultaneously in different directions in a photonic electromagnetic field in environment. They are involved in the formation of a wave of compression – decompression in this field under the influence of the antenna radiated photons. It is approved that the speed of photons of different frequencies can change within a wide range from 1,285·103 m/s (ν = 1024 Hz to 1,285·1012 m/s (ν = 106 Hz and, therefore, the speed of wave propagation in the electromagnetic environments that are filled by photons of the same frequency or a narrow frequency range can change widely from 8,58·102 m/s to 8,58·1011 m/s and be significantly different from the experimentally discovered speed of light. Interplanetary space in different parts of the Universe can be represented by different spectra of photons and therefore they will have different speed of

  9. Effect of the soft/hard exchange interaction on natural resonance frequency and electromagnetic wave absorption of the rare earth-iron-boron compounds

    Energy Technology Data Exchange (ETDEWEB)

    Maeda, Toru E-mail: maeda-toru@sei.co.jp; Sugimoto, Satoshi E-mail: sugimots@material.tohoku.ac.jp; Kagotani, Toshio; Tezuka, Nobuki; Inomata, Koichiro

    2004-10-01

    The effect of exchange interaction between the hard-magnetic Y{sub 2}Fe{sub 14}B and soft-magnetic Fe{sub 3}B phases on the natural resonance phenomenon and microwave absorption properties was investigated. The Y{sub 2}Fe{sub 14}B/Fe{sub 3}B ribbons were prepared by melt-spinning. The annealing at just above crystallization temperature of the ribbons and the Cu addition were effective to improve the exchange interaction between Y{sub 2}Fe{sub 14}B and Fe{sub 3}B phases. A linear relationship between the recoil ratio and the shift of resonance frequency was confirmed. The Y{sub 9.4}Fe{sub 79.3}B{sub 11.1}Cu{sub 0.2} ribbon, annealed at 1003 K, exhibited the largest recoil ratio of 0.49 and its resin composite showed the natural resonance frequency (f{sub r}) at 44 GHz, which was 23 GHz lower than that of the Y{sub 2}Fe{sub 14}B resin composite. The Y{sub 9.4}Fe{sub 79.3}B{sub 11.1}Cu{sub 0.2} composite also exhibited good microwave absorption properties (over 99%) at 39.5 GHz with the absorber thickness of 0.38 mm.

  10. Comparing the Robustness of High-Frequency Traveling-Wave Tube Slow-Wave Circuits

    Science.gov (United States)

    Chevalier, Christine T.; Wilson, Jeffrey D.; Kory, Carol L.

    2007-01-01

    A three-dimensional electromagnetic field simulation software package was used to compute the cold-test parameters, phase velocity, on-axis interaction impedance, and attenuation, for several high-frequency traveling-wave tube slow-wave circuit geometries. This research effort determined the effects of variations in circuit dimensions on cold-test performance. The parameter variations were based on the tolerances of conventional micromachining techniques.

  11. NUMERICAL STUDY OF ELECTROMAGNETIC WAVES GENERATED BY A PROTOTYPE DIELECTRIC LOGGING TOOL

    Science.gov (United States)

    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...

  12. NUMERICAL STUDY OF ELECTROMAGNETIC WAVES GENERATED BY A PROTOTYPE DIELECTRIC LOGGING TOOL

    Science.gov (United States)

    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...

  13. Plasma wave and third harmonic generation by a Gaussian electromagnetic beam in a collisionless magnetoplasma

    Energy Technology Data Exchange (ETDEWEB)

    Sodha, M.S.; Govind; Sharma, R.P. (Indian Inst. of Tech., New Delhi. Centre of Energy Studies)

    1981-05-01

    An investigation of the plasma wave and third harmonic generation by a Gaussian electromagnetic (em) beam, propagating in extraordinary mode in a collisionless hot magnetoplasma has been made. On account of the (VXB) force, a plasma wave at twice the pump wave frequency gets excited. The interaction of the plasma wave with the pump wave leads to third harmonic generation. By taking into account the self-focusing of the pump wave on account of non-uniform intensity distribution along the wave front, a modification is effected in the power of the plasma wave and the third harmonic em wave. The dependence of these phenomena on the strength of the static magnetic field has also been studied.

  14. EFFECTS OF LOW FREQUENCY ELECTROMAGNETIC FIELDON THE HUMAN BODY

    Directory of Open Access Journals (Sweden)

    PETRICA POPOV

    2016-06-01

    Full Text Available International standardization institutions, which play an important role in assessing the effects o f the field and determining the need to take protective measures for the human factor, developed safety standards on human exposure to electromagnetic field, differentiated for electric and magnetic fields of low frequency ( near fields, as well as to ele ctromagnetic radiation fields (far fields. Until recently, many studies has shown that the main harmful effect on the human body was produced by high frequency electromagnetic field, but in recent years, more and more information also reveals that the serious damage can be caused by low frequency electric and magnetic fields. These low -frequency electromagnetic fields interact with human tissue causing harmful effects, the degree of destruction depending on factors such as: intensity, frequency, energy f ield level and duration of exposure.

  15. Influence of shock wave pressure amplitude and pulse repetition frequency on the lifespan, size and number of transient cavities in the field of an electromagnetic lithotripter

    Science.gov (United States)

    Huber, Peter; Jöchle, Knut; Debus, Jürgen

    1998-10-01

    Monitoring the generation of cavitation is of great interest for diagnostic and therapeutic use of ultrasound in medicine, since cavitation is considered to play a major role in nonthermal ultrasound interactions with tissue. Important parameters are the number of cavitation events and the energy released during the bubble collapse. This energy is correlated to the maximum bubble radius which is related to the cavitation lifespan. The aim of this study was therefore to investigate the influence of the acoustic pressure amplitude and the pulse repetition frequency (PRF) in the field of a lithotripter (Lithostar, Siemens) on the number, size and lifespan of transient cavitation bubbles in water. We used scattered laser light recorded by a photodiode and stroboscopic photographs to monitor the cavitation activity. We found that PRF (range 0.5-5 Hz) had no influence on the cavitation bubble lifespan and size, whereas lifespan and size increased with the acoustic pressure amplitude. In contrast, the number of cavitation events strongly increased with PRF, whereas the pressure amplitude had no significant influence on the number of cavitation events. Thus, by varying the pressure amplitude and PRF, it might be possible to deliver a defined relative number of cavitations at a defined relative energy level in a defined volume. This seems to be relevant to further studies that address the biological effects of transient cavitation occurring in the fields of lithotripters.

  16. Excitation of high-frequency electromagnetic waves by energetic electrons with a loss cone distribution in a field-aligned potential drop

    Science.gov (United States)

    Fung, Shing F.; Vinas, Adolfo F.

    1994-01-01

    The electron cyclotron maser instability (CMI) driven by momentum space anisotropy (df/dp (sub perpendicular) greater than 0) has been invoked to explain many aspects, such as the modes of propagation, harmonic emissions, and the source characteristics of the auroral kilometric radiation (AKR). Recent satellite observations of AKR sources indicate that the source regions are often imbedded within the auroral acceleration region characterized by the presence of a field-aligned potential drop. In this paper we investigate the excitation of the fundamental extraordinary mode radiation due to the accelerated electrons. The momentum space distribution of these energetic electrons is modeled by a realistic upward loss cone as modified by the presence of a parallel potential drop below the observation point. On the basis of linear growth rate calculations we present the emission characteristics, such as the frequency spectrum and the emission angular distribution as functions of the plasma parameters. We will discuss the implication of our results on the generation of the AKR from the edges of the auroral density cavities.

  17. Condition for invariant spectrum of an electromagnetic wave scattered from an anisotropic random media.

    Science.gov (United States)

    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.

  18. An Apparatus for Constructing an Electromagnetic Plane Wave Model

    Science.gov (United States)

    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…

  19. 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...

  20. An Apparatus for Constructing an Electromagnetic Plane Wave Model

    Science.gov (United States)

    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…

  1. On new electromagnetic waves in a multicomponent insulator

    NARCIS (Netherlands)

    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

  2. Statistical Characterization of Electromagnetic Wave Propagation in Mine Environments

    KAUST Repository

    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.

  3. 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.

  4. Electron acceleration in the ionosphere by obliquely propagating electromagnetic waves

    Science.gov (United States)

    Burke, William J.; Ginet, Gregory P.; Heinemann, Michael A.; Villalon, Elena

    The paper presents an analysis of the relativistic equations of motion for electrons in magnetized plasma and externally imposed electromagnetic fields that propagate at arbitrary angles to the background magnetic field. The relativistic Lorentz equation for a test electron moving under the influence of an electromagnetic wave in a cold magnetized plasma and wave propagation through the ionospheric 'radio window' are examined. It is found that at wave energy fluxes greater than 10 to the 8th mW/sq m, initially cold electrons can be accelerated to energies of several MeV in less than a millisecond. Plans to test the theoretical results with rocket flights are discussed.

  5. Transition operators in electromagnetic-wave diffraction theory - General theory

    Science.gov (United States)

    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.

  6. Cosmological Electromagnetic Fields due to Gravitational Wave Perturbations

    CERN Document Server

    Marklund, M; Brodin, G; Marklund, Mattias; Dunsby, Peter K. S.; Brodin, Gert

    2000-01-01

    We consider the dynamics of electromagnetic fields in an almost-Friedmann-Robertson-Walker universe using the covariant and gauge-invariant approach of Ellis and Bruni. Focusing on the situation where deviations from the background model are generated by tensor perturbations only, we demonstrate that the coupling between gravitational waves and a weak magnetic test field can generate electromagnetic waves. We show that this coupling leads to an initial pulse of electromagnetic waves whose width and amplitude is determined by the wavelengths of the magnetic field and gravitational waves. A number of implications for cosmology are discussed, in particular we calculate an upper bound of the magnitude of this effect using limits on the quadrapole anisotropy of the Cosmic Microwave Background.

  7. Absorption of electromagnetic waves by the dust particles in a plasma

    Institute of Scientific and Technical Information of China (English)

    LI; Fang; LI; Lianlin; SUI; Qiang

    2004-01-01

    Absorption of electromagnetic waves by the dust particles in a plasma has been studied based on a Mie-Debye scattering mode. The longitudinal field of the Debye scattering has been derived and the wave energy loss from it has been calculated. It is shown that the lower the temperature of the plasma is and the higher the density of the plasma is, the larger the absorption cross section will be due to the longitudinal scattering.For the low frequency waves the electromagnetic waves scattered in a dusty plasma are mainly in the form of Debye scattering. In this case the energy loss due to the longitudinal scattering will affect the wave propagation seriously.

  8. Relativistic electromagnetic waves in an electron-ion plasma

    Science.gov (United States)

    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.

  9. Low-Frequency Waves in Cold Three-Component Plasmas

    Science.gov (United States)

    Fu, Qiang; Tang, Ying; Zhao, Jinsong; Lu, Jianyong

    2016-09-01

    The dispersion relation and electromagnetic polarization of the plasma waves are comprehensively studied in cold electron, proton, and heavy charged particle plasmas. Three modes are classified as the fast, intermediate, and slow mode waves according to different phase velocities. When plasmas contain positively-charged particles, the fast and intermediate modes can interact at the small propagating angles, whereas the two modes are separate at the large propagating angles. The near-parallel intermediate and slow waves experience the linear polarization, circular polarization, and linear polarization again, with the increasing wave number. The wave number regime corresponding to the above circular polarization shrinks as the propagating angle increases. Moreover, the fast and intermediate modes cause the reverse change of the electromagnetic polarization at the special wave number. While the heavy particles carry the negative charges, the dispersion relations of the fast and intermediate modes are always separate, being independent of the propagating angles. Furthermore, this study gives new expressions of the three resonance frequencies corresponding to the highly-oblique propagation waves in the general three-component plasmas, and shows the dependence of the resonance frequencies on the propagating angle, the concentration of the heavy particle, and the mass ratio among different kinds of particles. supported by National Natural Science Foundation of China (Nos. 11303099, 41531071 and 41574158), and the Youth Innovation Promotion Association CAS

  10. AN INVESTIGATION OF ELECTROMAGNETIC WAVE PROPAGATION IN PLASMA BY SHOCK TUBE

    Institute of Scientific and Technical Information of China (English)

    ZHU Naiyi; LI Xuefen; HUANG Lishun; YU Xilong; YANG Qiansuo

    2004-01-01

    This paper presents the electromagnetic wave propagation characteristics in plasma and the attenuation coefficients of the microwave in terms of the parameters ne, v, ω, L, ωb. The φ800 mm high temperature shock tube has been used to produce a uniform plasma. In order to get the attenuation of the electromagnetic wave through the plasma behind a shock wave, the microwave transmission has been used to measure the relative change of the wave power. The working frequency is f = (2 ~ 35) GHz (ω = 2π f, wave length λ = 15 cm ~ 8 mm). The electron density in the plasma is ne = (3 × 1010 ~ 1× 1014) cm-3. The collision frequency v = (1× 10s ~ 6 × 1010)Hz. The thickness of the plasma layer L = (2 ~ 80) cm. The electron circular frequency ωb = eBo/me, magnetic flux density B0 = (0 ~ 0.84)T. The experimental results show that when the plasma layer is thick (such as L/λ≥ 10), the correlation between the attenuation coefficients of the electromagnetic waves and the parameters ne, v, ω, L determined from the measurements are in good agreement with the theoretical predictions of electromagnetic wave propagations in the uniform infinite plasma. When the plasma layer is thin (such as when both L and λ are of the same order), the theoretical results are only in a qualitative agreement with the experimental observations in the present parameter range,but the formula of the electromagnetic wave propagation theory in an uniform infinite plasma can not be used for quantitative computations of the correlation between the attenuation coefficients and the parameters ne, v, ω, L. In fact, if ω<ωp, v2 <<ω2, the power attenuations K of the electromagnetic waves obtained from the measurements in the thin-layer plasma are much smaller than those of the theoretical predictions. On the other hand, if ω>ωp, v2 <<ω2 (just v ≈ f), the measurements are much larger than the theoretical results. Also, we have measured the electromagnetic wave power

  11. 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.

  12. PROPAGATION OF ELECTROMAGNETIC WAVE IN THE THREE PHASES SOIL MEDIA

    Institute of Scientific and Technical Information of China (English)

    陈云敏; 边学成; 陈仁朋; 梁志刚

    2003-01-01

    The fundamental parameters such as dielectric permittivity and magnetic permeability are required to solve the propagation of electromagnetic wave (EM Wave) in the soil. Based on Maxwell equations, the equivalent model is proposed to calculate the dielectric permittivity of mixed soil. The results of calculation fit. the test data well and will provide solid foundation for the application of EM wave in the soil moisture testing, CT analyzing of soil and the inspecting of geoenvironment.

  13. Design of Metamaterials for control of electromagnetic waves

    Science.gov (United States)

    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

  14. Metamaterial Absorber for Electromagnetic Waves in Periodic Water Droplets

    Science.gov (United States)

    Yoo, Young Joon; Ju, Sanghyun; Park, Sang Yoon; Ju Kim, Young; Bong, Jihye; Lim, Taekyung; Kim, Ki Won; Rhee, Joo Yull; Lee, Youngpak

    2015-09-01

    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.

  15. Metamaterial Absorber for Electromagnetic Waves in Periodic Water Droplets.

    Science.gov (United States)

    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.

  16. Metamaterial Absorber for Electromagnetic Waves in Periodic Water Droplets

    Science.gov (United States)

    Yoo, Young Joon; Ju, Sanghyun; Park, Sang Yoon; Ju Kim, Young; Bong, Jihye; Lim, Taekyung; Kim, Ki Won; Rhee, Joo Yull; Lee, YoungPak

    2015-01-01

    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. PMID:26354891

  17. Simulations of electromagnetic effects in high frequency capacitively coupled discharges using the Darwin approximation

    CERN Document Server

    Eremin, Denis; Brinkmann, Ralf Peter; Mussenbrock, Thomas

    2012-01-01

    The Darwin approximation is investigated for its possible use in simulation of electromagnetic effects in large size, high frequency capacitively coupled discharges. The approximation is utilized within the framework of two different fluid models which are applied to typical cases showing pronounced standing wave and skin effects. With the first model it is demonstrated that Darwin approximation is valid for treatment of such effects in the range of parameters under consideration. The second approach, a reduced nonlinear Darwin approximation-based model, shows that the electromagnetic phenomena persist in a more realistic setting. The Darwin approximation offers a simple and efficient way of carrying out electromagnetic simulations as it removes the Courant condition plaguing explicit electromagnetic algorithms and can be implemented as a straightforward modification of electrostatic algorithms. The algorithm described here avoids iterative schemes needed for the divergence cleaning and represents a fast and ...

  18. 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.

  19. Polarization of low-frequency electromagnetic radiation in the lobes of Jupiter's magnetotail

    Science.gov (United States)

    Moses, S. L.; Kennel, C. F.; Coroniti, F. V.; Scarf, F. L.; Kurth, W. S.

    1987-01-01

    The plasma wave instruments on the Voyager spacecraft have detected intense electromagnetic radiation within the lobes of Jupiter's magnetic tail down to the lowest frequency of the detector (10 Hz). During a yaw maneuver performed by Voyager 1 in the lobe of the Jovian magnetotail, a modulation appeared in the amplitudes of waves detected in the 10-, 17.8- and 31.1-Hz channels of the plasma wave analyzer, well below the local electron cyclotron frequency of 260 Hz. The lowest amplitudes occurred when the antenna axis was most nearly parallel to the magnetic field. Wave amplitudes in the 56.2-Hz and higher frequency channels remained nearly constant during the maneuver. From the cold-plasma theory of electromagnetic waves, it is concluded that the plasma frequency was between the 56.2- and 31.1-Hz channels where the parallel-polarized component of the spectrum cuts off. This implies a tail-lobe density between 0.000032 and 0.000015/cu cm. The left-hand cutoff frequency would then be below 10 Hz, consistent with either the Z-mode (L, X) or whistlers (R-mode) in the modulated channels.

  20. The modulation of electromagnetic ion cyclotron waves by Pc 5 ULF waves

    Directory of Open Access Journals (Sweden)

    T. M. Loto'aniu

    2009-01-01

    Full Text Available The modulation of electromagnetic ion cyclotron (EMIC waves by longer-period ULF waves has been proposed as a method for producing pearl structured Pc 1–2 EMIC waves. This study examines frequency and phase relationship between Pc 1 EMIC wavepacket envelopes and simultaneously occurring Pc 5 ULF waves using magnetic data measured by the CRRES spacecraft. Intervals from three days in 1991 where CRRES observed pearls are presented along with simple statistics for 58 EMIC wavepackets. The observations were dominated by EMIC waves propagating away from the equatorial region. Comparisons between pearl wavepacket envelopes and Pc 5 waves show excellent agreement. The pearl wavepacket duration times, τdur, were statistically correlated with Pc 5 wave periods, TPc5, resulting in a correlation coefficient of R=0.7 and best fit equation τdur=0.8·TPc5+6 s. In general, phase differences varied although time intervals of constant in-phase or anti-phase correlation were observed. Anti-phase modulation may be explained by a decreasing background magnetic field due to the negative cycle of the ULF wave decreasing Alfvén velocity and minimum resonant energy. In-phase modulation could be the result of adiabatic modulation of temperature anisotropy in-phase with variations in the background field. Non-adiabatic processes may contribute to intervals that showed varying phase differences with time. Results suggest that future theoretical developments should take into account the full range of possible wave particle interactions inside the magnetosphere.

  1. A novel protocol to measure the attenuation of electromagnetic waves through smoke

    Science.gov (United States)

    Yan-wu, Li; Hong-yong, Yuan; Yang, Lu; Xiaoxiang, Zhang; Ru-feng, Xu; Ming, Fu

    2016-06-01

    The electromagnetic properties of smoke from a structure fire are important in terms of their relation to the stability of wireless communication systems used in fire rescue. As it is hard to make a measurable electromagnetic environment for particles in the air, compressed and bulk samples are used instead to measure sand storms and smoke plumes. In this paper, an experiment system was designed to measure smoke particles in the air, in consideration of both smoke control and electromagnetic measurement. Several measures had been taken to create a fulfilled smoke environment. The simulated and measured transmission parameters of the electromagnetic testing area were approximate and the electromagnetic wave frequencies were set from 350 to 400 MHz. Repeated experiments have been conducted to test the stability of the results and they showed that there was no obvious attenuation until the smoke concentration was more than 10 dB m-1. It was found that the frequency around 355 and 360 MHz had a larger attenuation coefficient. The relationship between the attenuation coefficient and the smoke concentration was concluded to be linear. The results may help us understand the attenuation of electromagnetic waves within a smoke column.

  2. Effects of microwave and radio frequency electromagnetic fields on lichens.

    Science.gov (United States)

    Urech, M; Eicher, B; Siegenthaler, J

    1996-01-01

    The effects of electromagnetic fields on lichens were investigated. Field experiments of long duration (1-3 years) were combined with laboratory experiments and theoretical considerations. Samples of the lichen species Parmelia tiliacea and Hypogymnia physodes were exposed to microwaves (2.45 GHz; 0.2, 5, and 50 mW/cm2; and control). Both species showed a substantially reduced growth rate at 50 mW/cm2. A differentiation between thermal and nonthermal effects was not possible. Temperature measurements on lichens exposed to microwaves (2.45 GHz, 50 mW/cm2) showed a substantial increase in the surface temperature and an accelerated drying process. The thermal effect of microwave on lichens was verified. The exposure of lichens of both species was repeated near a short-wave broadcast transmitter (9.5 MHz, amplitude modulated; maximum field strength 235 V/m, 332 mA/m). No visible effects on the exposed lichens were detected. At this frequency, no thermal effects were expected, and the experimental results support this hypothesis. Theoretical estimates based on climatic data and literature showed that the growth reductions in the initial experiments could very likely have been caused by drying of the lichens from the heating with microwaves. The results of the other experiments support the hypothesis that the response of the lichens exposed to microwaves was mainly due to thermal effects and that there is a low probability of nonthermal effects.

  3. A metasurface carpet cloak for electromagnetic, acoustic and water waves.

    Science.gov (United States)

    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.

  4. 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.

  5. Cell therapy for spinal cord injury informed by electromagnetic waves.

    Science.gov (United States)

    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.

  6. Geodetic refraction effects of electromagnetic wave propagation through the atmosphere

    CERN Document Server

    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...

  7. Propagation of electromagnetic waves parallel to the magnetic field in the nightside Venus ionosphere

    Science.gov (United States)

    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.

  8. Plane linear waves in deformable electromagnetic materials with an extended description of the electromagnetism

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmann, T.; Strawinska, J. [Politechnika Poznanska, Poznan (Poland)

    1993-12-31

    The present considerations are devoted to the description of an electromagnetic field in deformable body within the framework of the conceptional extended electrodynamics. The formal tool used is the classical field theory based on methods of analytical mechanics. The deformation is described by applying the relativistic kinematics of a medium which makes it possible to obtain, as a particular case, three dimensional laws with simple physical interpretation. The dynamics of bodies interacting with an electromagnetic field has been expressed by Lagrange`s equation of motion with a view to obtaining linear field equations. In the domain of wave problems one-dimensional volume waves have been analysed. (author). 19 refs.

  9. Transmission of Information by Longitudinal Electromagnetic Waves

    CERN Document Server

    Barashenkov, V S; Yuriev, M Z

    2001-01-01

    In Maxwell electrodynamics longitudinal wave irradiation is strongly forbidden by the so-called gauge invariance. However, these waves are present in virtual quantum processes and they can be used to transfer information at macroscopic distances by the displacement of the interference picture due to the change of the phase of electron wave function. The transmission can be carried out so that it will be hidden for usual observation.

  10. Measurement of the environmental broadband electromagnetic waves in a mid-size European city.

    Science.gov (United States)

    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.

  11. Evaluation Of Electromagnetic Fields For Frequencies 900 MHz-1 800 MHz In Tirana

    Directory of Open Access Journals (Sweden)

    Kuqi Dhurata

    2015-07-01

    Full Text Available Abstract The massive use of mobile phone as a communication tool nowadays is accompanied the ever increasing interest of the public and researchers for the possibly impact on human health as a result of exposure to the electromagnetic fields that accompany these devices. Therefore knowing the level of exposure electromagnetic fields of this electronic equipment has been and will be in the future interest object to the public and the subject of study for the researchers. In this paper are presents the results of measurements of electromagnetic fields for the frequencies 900 MHz - 1800 MHz used in mobile telephone in Tirana. These frequencies are included in the area radio frequency RF and Microwave MW 300 Hz - 300 GHz in the spectrum of electromagnetic waves and belong to non-ionizing radiation. The measurements were performed in different areas of Tirana. The purpose is to assess the level of exposure electromagnetic fields especially near areas where mobile antennas are mounted construction of dynamic digital mapping and comparison with the permitted levels of the exposure defined by the International Commission of Non Ionizing Radiation Protection ICNIRP. Through this publication the aim of the authors is to provide real information and reliable for the population.

  12. Propagation of Electromagnetic Waves in Extremely Dense Media

    CERN Document Server

    Masood, Samina

    2016-01-01

    We study the propagation of electromagnetic (EM) waves in extremely dense exotic systems with very unique properties. These EM waves develop a longitudinal component due to its interaction with the medium. Renormalization scheme of QED is used to understand the propagation of EM waves in both longitudinal and transverse directions. The propagation of EM waves in a quantum statistically treatable medium affects the properties of the medium itself. The electric permittivity and the magnetic permeability of the medium are modified and influence the related behavior of the medium. All the electromagnetic properties of a medium become a function of temperature and chemical potential of the medium. We study in detail the modifications of electric permittivity and magnetic permeability and other related properties of a medium in the superdense stellar objects.

  13. On the interaction of electromagnetic waves with conductors

    CERN Document Server

    Paranjape, B V

    2012-01-01

    We study the interaction of electromagnetic waves with electrons. Our results can be applied to radio waves in the ionosphere or to lasers impinging on metals causing melting. We generalize the classical analysis of Zener to the case which includes the interactions of the electrons with lattice vibrations or the positive ions. We use the induced polarization to give a globally coherent and unifying analysis of the two cases, where collisions are important and where they are negligible.

  14. Electronic Wave Packet in a Quantized Electromagnetic Field

    Institute of Scientific and Technical Information of China (English)

    程太旺; 薛艳丽; 李晓峰; 吴令安; 傅盘铭

    2002-01-01

    We study a non-stationary electronic wave packet in a quantized electromagnetic field. Generally, the electron and field become entangled as the electronic wave packet evolves. Here we find that, when the initial photon state is a coherent one, the wavefunction of the system can be factorized if we neglect the transferred photon number. In this case, the quantized-field calculation is equivalent to the semi-classical calculation.

  15. The Oblique Incident Effects of Electromagnetic Wave in Atmospheric Pressure Plasma Layers

    Institute of Scientific and Technical Information of China (English)

    HE Yong; JIANG Zhonghe; HU Xiwei; LIU Minghai

    2008-01-01

    The propagating behaviours, i.e. phase shift, transmissivity, reflectivity and absorptivity, of an electromagnetic (EM) wave in a two-dimensional atmospheric pressure plasma layer are described by the numerical solutions of integral-differential Maxwell's equations through a generalized finite-difference-time-domain (FDTD) algorithm. These propagating behaviours are found to be strongly affected by five factors: two EM wave characteristics relevan.t to the oblique incident and three dimensionless factors. The two EM wave factors are the polarization mode (TM mode or TE mode) and its incident angle. The three dimensionless factors are: the ratio of the maximum electron density to the critical density n0/ncr, the ratio of the plasma layer width to the wave length d/λ, and the ratio of the collision frequency between electrons and neutrals to the incident wave frequency ve0/f.

  16. High-frequency homogenization for travelling waves in periodic media.

    Science.gov (United States)

    Harutyunyan, Davit; Milton, Graeme W; Craster, Richard V

    2016-07-01

    We consider high-frequency homogenization in periodic media for travelling waves of several different equations: the wave equation for scalar-valued waves such as acoustics; the wave equation for vector-valued waves such as electromagnetism and elasticity; and a system that encompasses the Schrödinger equation. This homogenization applies when the wavelength is of the order of the size of the medium periodicity cell. The travelling wave is assumed to be the sum of two waves: a modulated Bloch carrier wave having crystal wavevector [Formula: see text] and frequency ω1 plus a modulated Bloch carrier wave having crystal wavevector [Formula: see text] and frequency ω2. We derive effective equations for the modulating functions, and then prove that there is no coupling in the effective equations between the two different waves both in the scalar and the system cases. To be precise, we prove that there is no coupling unless ω1=ω2 and [Formula: see text] where Λ=(λ1λ2…λ d ) is the periodicity cell of the medium and for any two vectors [Formula: see text] the product a⊙b is defined to be the vector (a1b1,a2b2,…,adbd ). This last condition forces the carrier waves to be equivalent Bloch waves meaning that the coupling constants in the system of effective equations vanish. We use two-scale analysis and some new weak-convergence type lemmas. The analysis is not at the same level of rigour as that of Allaire and co-workers who use two-scale convergence theory to treat the problem, but has the advantage of simplicity which will allow it to be easily extended to the case where there is degeneracy of the Bloch eigenvalue.

  17. High-frequency homogenization for travelling waves in periodic media

    Science.gov (United States)

    Harutyunyan, Davit; Milton, Graeme W.; Craster, Richard V.

    2016-07-01

    We consider high-frequency homogenization in periodic media for travelling waves of several different equations: the wave equation for scalar-valued waves such as acoustics; the wave equation for vector-valued waves such as electromagnetism and elasticity; and a system that encompasses the Schrödinger equation. This homogenization applies when the wavelength is of the order of the size of the medium periodicity cell. The travelling wave is assumed to be the sum of two waves: a modulated Bloch carrier wave having crystal wavevector k and frequency ω1 plus a modulated Bloch carrier wave having crystal wavevector m and frequency ω2. We derive effective equations for the modulating functions, and then prove that there is no coupling in the effective equations between the two different waves both in the scalar and the system cases. To be precise, we prove that there is no coupling unless ω1=ω2 and (k -m )⊙Λ ∈2 π Zd, where Λ=(λ1λ2…λd) is the periodicity cell of the medium and for any two vectors a =(a1,a2,…,ad),b =(b1,b2,…,bd)∈Rd, the product a⊙b is defined to be the vector (a1b1,a2b2,…,adbd). This last condition forces the carrier waves to be equivalent Bloch waves meaning that the coupling constants in the system of effective equations vanish. We use two-scale analysis and some new weak-convergence type lemmas. The analysis is not at the same level of rigour as that of Allaire and co-workers who use two-scale convergence theory to treat the problem, but has the advantage of simplicity which will allow it to be easily extended to the case where there is degeneracy of the Bloch eigenvalue.

  18. Response of thermal ions to electromagnetic ion cyclotron waves

    Science.gov (United States)

    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.

  19. Response of thermal ions to electromagnetic ion cyclotron waves

    Science.gov (United States)

    Anderson, B. J.; Fuselier, S. A.

    1994-10-01

    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.

  20. A Lanczos model-order reduction technique to efficiently simulate electromagnetic wave propagation in dispersive media

    Science.gov (United States)

    Zimmerling, Jörn; Wei, Lei; Urbach, Paul; Remis, Rob

    2016-06-01

    In this paper we present a Krylov subspace model-order reduction technique for time- and frequency-domain electromagnetic wave fields in linear dispersive media. Starting point is a self-consistent first-order form of Maxwell's equations and the constitutive relation. This form is discretized on a standard staggered Yee grid, while the extension to infinity is modeled via a recently developed global complex scaling method. By applying this scaling method, the time- or frequency-domain electromagnetic wave field can be computed via a so-called stability-corrected wave function. Since this function cannot be computed directly due to the large order of the discretized Maxwell system matrix, Krylov subspace reduced-order models are constructed that approximate this wave function. We show that the system matrix exhibits a particular physics-based symmetry relation that allows us to efficiently construct the time- and frequency-domain reduced-order models via a Lanczos-type reduction algorithm. The frequency-domain models allow for frequency sweeps meaning that a single model provides field approximations for all frequencies of interest and dominant field modes can easily be determined as well. Numerical experiments for two- and three-dimensional configurations illustrate the performance of the proposed reduction method.

  1. Electromagnetically induced transparency in metamaterials at near-infrared frequency

    DEFF Research Database (Denmark)

    Zhang, Jingjing; Xiao, Sanshui; Jeppesen, Claus

    2010-01-01

    We employ a planar metamaterial structure composed of a splitring-resonator (SRR) and paired nano-rods to experimentally realize a spectral response at near-infrared frequencies resembling that of electromagnetically induced transparency. A narrow transparency window associated with low loss...

  2. Effect of environment on the propagation of electromagnetic waves in GRC 408E digital radiorelay devices

    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

  3. Stimulated Electromagnetic Emission Indicator of Glow Plasma Discharges from Ionospheric HF Wave Transmissions with HAARP

    Science.gov (United States)

    Bernhardt, P. A.; Scales, W.; Briczinski, S. J.; Fu, H.; Mahmoudian, A.; Samimi, A.

    2012-12-01

    High power radio waves resonantly interact with to accelerate electrons for production of artificial aurora and plasma clouds. These plasma clouds are formed when the HF frequency is tuned near a harmonic of the electron cyclotron frequency. At a narrow band resonance, large electrostatic fields are produced below the F-layer and the neutral atmosphere breaks down with a glow plasma discharge. The conditions for this resonance are given by matching the pump wave frequency and wave-number with the sum of daughter frequencies and wave-numbers for several plasma modes. The most likely plasma mode that accelerates the electrons is the electron Bernstein wave in conjunction with an ion acoustic wave. Both upper hybrid and whistler mode waves are also possible sources of electron acceleration. To determine the plasma process for electron acceleration, stimulated electromagnetic emissions are measured using ground receivers in a north-south chain from the HAARP site. Recent observations have shown that broad band spectral lines downshifted from the HF pump frequency are observed when artificial plasma clouds are formed. For HF transmissions are the 2nd, 3rd, and 4th gyro harmonic, the downshifted indicators are found 500 Hz, 20 kHz, and 140 kHz, respectively, from the pump frequency. This Indicator Mode (IM) anticipates that a plasma layer will be formed before it is recorded with an ionosonde or optical imager.

  4. Frequency-controls of electromagnetic multi-beam scanning by metasurfaces.

    Science.gov (United States)

    Li, Yun Bo; Wan, Xiang; Cai, Ben Geng; Cheng, Qiang; Cui, Tie Jun

    2014-01-01

    We propose a method to control electromagnetic (EM) radiations by holographic metasurfaces, including to producing multi-beam scanning in one dimension (1D) and two dimensions (2D) with the change of frequency. The metasurfaces are composed of subwavelength metallic patches on grounded dielectric substrate. We present a combined theory of holography and leaky wave to realize the multi-beam radiations by exciting the surface interference patterns, which are generated by interference between the excitation source and required radiation waves. As the frequency changes, we show that the main lobes of EM radiation beams could accomplish 1D or 2D scans regularly by using the proposed holographic metasurfaces shaped with different interference patterns. This is the first time to realize 2D scans of antennas by changing the frequency. Full-wave simulations and experimental results validate the proposed theory and confirm the corresponding physical phenomena.

  5. A possible mechanism of current in medium under electromagnetic wave

    Institute of Scientific and Technical Information of China (English)

    Zhang Tao

    2006-01-01

    In this paper a possible mechanism of current in medium is presented. Comparison between this current and the magnetization current was made. Expression for this current was derived. This work is helpful to understanding the interaction between medium and electromagnetic wave.

  6. Propagation and Generation of Electromagnetic Waves at Proton Gyrofrequencies in a Relativistic Electron-Positron Plasma. II. Excitation of Electromagnetic Waves

    Science.gov (United States)

    Zheleznyakov, V. V.; Bespalov, P. A.

    2016-04-01

    In part I of this work [1], we study the dispersion characteristics of low-frequency waves in a relativistic electron-positron plasma. In part II, we examine the electromagnetic wave instability in this plasma caused by an admixture of nonrelativistic protons with energy comparable with the energy of relativistic low-mass particles. The instability occurs in the frequency band between the fundamental harmonic of proton gyrofrequency and the fundamental harmonic of relativistic electron gyrofrequency. The results can be used for the interpretation of known observations of the pulsar emissions obtained with a high time and frequency resolution. The considered instability can probably be the initial stage of the microwave radio emission nanoshots typical of the pulsar in the Crab Nebula.

  7. Detection of leukemia using electromagnetic waves

    Science.gov (United States)

    Colton, David L.; Monk, Peter

    1995-10-01

    The presence of leukemia in bone marrow causes an increase in the electric permittivity and a decrease in the conductivity of the marrow. This suggests the possibility of detecting leukemia by electromagnetic imaging. We show how this can be done for the case of an absorbing host medium (i.e. water) and provide numerical experiments using synthetic data for detecting proliferated tissue at localized portions of the bone marrow. We do not assume that the refractive index of the fat, bone, and muscle are known but will instead recover these values as part of the imaging process.

  8. 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.

  9. Modeling the propagation of electromagnetic waves over the surface of the human body

    Science.gov (United States)

    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.

  10. On the Superposition and Elastic Recoil of Electromagnetic Waves

    CERN Document Server

    Schantz, Hans G

    2014-01-01

    Superposition demands that a linear combination of solutions to an electromagnetic problem also be a solution. This paper analyzes some very simple problems: the constructive and destructive interferences of short impulse voltage and current waves along an ideal free-space transmission line. When voltage waves constructively interfere, the superposition has twice the electrical energy of the individual waveforms because current goes to zero, converting magnetic to electrical energy. When voltage waves destructively interfere, the superposition has no electrical energy because it transforms to magnetic energy. Although the impedance of the individual waves is that of free space, a superposition of waves may exhibit arbitrary impedance. Further, interferences of identical waveforms allow no energy transfer between opposite ends of a transmission line. The waves appear to recoil elastically one from another. Although alternate interpretations are possible, these appear less likely. Similar phenomenology arises i...

  11. Experimental verification of effect of horizontal inhomogeneity of evaporation duct on electromagnetic wave propagation

    Institute of Scientific and Technical Information of China (English)

    史阳; 杨坤德; 杨益新; 马远良

    2015-01-01

    The evaporation duct which forms above the ocean surface has a significant influence on electromagnetic wave prop-agation above 2 GHz over the ocean. The effects of horizontal inhomogeneity of evaporation duct on electromagnetic wave propagation are investigated, both in numerical simulation and experimental observation methods, in this paper. Firstly, the features of the horizontal inhomogeneity of the evaporation duct are discussed. Then, two typical inhomogeneous cases are simulated and compared with the homogeneous case. The result shows that path loss is significantly higher than that in the homogeneous case when the evaporation duct height (EDH) at the receiver is lower than that at the transmitter. It is also concluded that the horizontal inhomogeneity of the evaporation duct has a significant influence when the EDH is low or when the electromagnetic wave frequency is lower than 13 GHz. Finally, experimental data collected on a 149-km long propagation path in the South China Sea in 2013 are used to verify the conclusion. The experimental results are consis-tent with the simulation results. The horizontal inhomogeneity of evaporation duct should be considered when modeling electromagnetic wave propagation over the ocean.

  12. Scattering of electromagnetic light waves from a deterministic anisotropic medium

    Science.gov (United States)

    Li, Jia; Chang, Liping; Wu, Pinghui

    2015-11-01

    Based on the weak scattering theory of electromagnetic waves, analytical expressions are derived for the spectral densities and degrees of polarization of an electromagnetic plane wave scattered from a deterministic anisotropic medium. It is shown that the normalized spectral densities of scattered field is highly dependent of changes of the scattering angle and degrees of polarization of incident plane waves. The degrees of polarization of scattered field are also subjective to variations of these parameters. In addition, the anisotropic effective radii of the dielectric susceptibility can lead essential influences on both spectral densities and degrees of polarization of scattered field. They are highly dependent of the effective radii of the medium. The obtained results may be applicable to determine anisotropic parameters of medium by quantitatively measuring statistics of a far-zone scattered field.

  13. Monitoring dynamic reactions of red blood cells to UHF electromagnetic waves radiation using a novel micro-imaging technology.

    Science.gov (United States)

    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.

  14. Impact of Fog on Electromagnetic Wave Propagation

    Science.gov (United States)

    Morris, Jonathon; Fleisch, Daniel

    2002-04-01

    This experiment was designed to explore the impact of fog on electromagnetic radiation, in particular microwaves and infrared light. For years law enforcement agencies have used microwave radiation (radar guns) to measure the speed of vehicles, and the last ten years has seen increased use of LIDAR, which uses 905-nm infrared radiation rather than microwaves. To evaulate the effect of fog on the operation of these devices, we have constructed a fog chamber with microwave and optical portals to allow light from a HeNe laser and 10.6-GHz microwaves to propagate through various densities of fog. Data is acquired using Vernier Logger Pro and analyzed using MATLAB and Mathematica. Using the attenuation of the laser light to determine fog density, the impact of fog on the signal-to-noise ratio of both microwave and IR devices may be quantified, and the maximum useful range may be calculated.

  15. 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...... lead screw (MLS) employing permanent magnets only, the new EMLS proposed uses dc current to provide the required helical-shape magnetic field, offering a much simpler, robust structure compared with the MLS. The working principle and the performances of this EMLS are analyzed in this paper. Comparison...

  16. Electromagnetic fields induced at the seafloor by Rayleigh-Stoneley waves

    Energy Technology Data Exchange (ETDEWEB)

    Webb, S.; Cobb, C.

    1982-05-10

    We model oceanic acoustic and seismic disturbances as Rayeigh-Stoneley waves in the layered medium consisting of ocean, sediment and rock. The waves induce electromagnetic fields because of motion of conducting materials through the geomagnetic field. Low-frequency disturbances in deep water are efficient electromagnetic generators because the motions are coherent over large volumes of highly conducting seawater. For wave frequencies below 0.1 Hz in deep water, the geomagnetic field is nearly frozen to the moving water. Consequently, the electric field measured by a voltmeter attached to the seabed is approximately ..delta..u x F, where ..delta..u is the difference between the velocity of the water and of the voltmeter itself as it is moved by the motion of the seafloor, and F is the geomagnetic field. This result applied to Love waves suggests that the electric field will result largely from the movement of the detector but detailed calculations have not been made. Although the fields are weak they should be detectable because the main interference is from ionospheric sources and the fields from, these sources are greatly attenuated at the seabed by the overlying oceanic shield. The effectiveness of the shield diminishes sharply at frequencies below 0.03 Hz. At high frequencies the principal limitation to detectability is in the inherent noise level of detectors whether electric or magnetic. At present, electric detectors are more effective than magnetic. They appear to be competitive with accelerometers for seismic detection in the deep ocean in a restricted frequency band near 0.05 Hz. A layer of unconsolidated sediment underlying the ocean profoundly affects the dispersion relation of Rayleigh-Stonely waves and thereby affects the electromagnetic induction process.

  17. Electromagnetic radiation trapped in the magnetosphere above the plasma frequency

    Science.gov (United States)

    Gurnett, D. A.; Shaw, R. R.

    1973-01-01

    An electromagnetic noise band is frequently observed in the outer magnetosphere by the Imp 6 spacecraft at frequencies from about 5 to 20 kHz. This noise band generally extends throughout the region from near the plasmapause boundary to near the magnetopause boundary. The noise typically has a broadband field strength of about 5 microvolts/meter. The noise band often has a sharp lower cutoff frequency at about 5 to 10 kHz, and this cutoff has been identified as the local electron plasma frequency. Since the plasma frequency in the plasmasphere and solar wind is usually above 20 kHz, it is concluded that this noise must be trapped in the low-density region between the plasmapause and magnetopause boundaries. The noise bands often contain a harmonic frequency structure which suggests that the radiation is associated with harmonics of the electron cyclotron frequency.

  18. Finite element approach analysis for characteristics of electromagnetic acoustic Lamb wave

    Science.gov (United States)

    Chen, Xiaoming; Li, Songsong

    2016-04-01

    The electromagnetic acoustic Lamb wave, with the advantages of quickly detecting the defect and sensitivity to the defects, is widely used in non-destructive testing of thin sheet. In this paper, the directivity of sound field, Phase velocity, group velocity and particle displacement amplitude of Lamb wave are study based on finite element analysis method. The results show that, for 1mm aluminum, when the excitation frequency 0.64MHz, the displacement amplitude of A0 mode is minimum, and the displacement amplitude S0 mode is largest. Appropriate to increase the displacement amplitude of a mode, while reducing displacement amplitude of another mode, to achieve the excitation of a single mode Lamb wave. It is helpful to the Optimization of transducer parameters, the choice of Lamb wave modes and providing optimal excitation frequency.

  19. Physical modeling of small shallow conductive 3-D targets with high-frequency electromagnetics

    Energy Technology Data Exchange (ETDEWEB)

    Birken, R.A.; Poulton, M.; Sterngerg, B.K.

    1996-09-01

    The goal of this study is to show that physical modeling can provide important support for three-dimensional (3D) interpretation of electromagnetic geophysical data for environmental problems. This is specially true when high-frequency electromagnetic methods are used, which are difficult to model with existing 3D forward modeling programs. Existing electromagnetic geophysical systems usually operate in the frequency range of a few hertz to several hundred hertz. For environmental problems, such as characterization of waste sites, systems with higher frequencies are desirable. This is because at lower frequencies, the depth of investigation is too deep for environmental characterizations. This leads to subsurface images, which don`t have enough resolution to map small shallow objects. Electromagnetic 3D modeling programs which solve the full wave equation are still not widely available, even though 3D modeling has improved remarkably during the last few years (Oristaglio and Spies, 1995). Since such a program was not available for this study, we used a specialized 3D program EM1DSH (Zhou, 1989). With this program, we can model layered-earth cases, taking dielectric effects into account over the whole frequency range of interest. Stewart et al. (1994) published ellipticity curves for similar system configurations and frequency ranges that indicate that dielectric effects can not be neglected for model calculations using frequencies above several 100 kHz. EM1DSH can also model thin conductive sheets in a two-layer earth but neglecting dielectric effects. Therefore we are only able to model and compare our field data with 3D forward modeling results for the lower frequencies. One way of bridging the gap between the interpretation needs and limitations of existing 3D forward modeling programs is to conduct physical modeling experiments. 6 refs., 2 figs.

  20. Spatial dependence of electromagnetic ion cyclotron waves triggered by solar wind dynamic pressure enhancements

    Science.gov (United States)

    Cho, J.-H.; Lee, D.-Y.; Noh, S.-J.; Kim, H.; Choi, C. R.; Lee, J.; Hwang, J.

    2017-05-01

    In this paper, using the multisatellite (the Van Allen Probes and two GOES satellites) observations in the inner magnetosphere, we examine two electromagnetic ion cyclotron (EMIC) wave events that are triggered by Pdyn enhancements under prolonged northward interplanetary magnetic field quiet time preconditions. For both events, the impact of enhanced Pdyn causes EMIC waves at multiple points. However, we find a strong spatial dependence that EMIC waves due to enhanced Pdyn impact can occur at multiple points (likely globally but not necessarily everywhere) but with different wave properties. For Event 1, three satellites situated at a nearly same dawnside zone but at slightly different L shells see occurrence of EMIC waves but in different frequencies relative to local ion gyrofrequencies and with different polarizations. These waves are found inside or at the outer edge of the plasmasphere. Another satellite near noon observes no dramatic EMIC wave despite the strongest magnetic compression there. For Event 2, the four satellites are situated at widely separated magnetic local time zones when they see occurrence of EMIC waves. They are again found at different frequencies relative to local ion gyrofrequencies with different polarizations and all outside the plasmasphere. We propose two possible explanations that (i) if triggered by enhanced Pdyn impact, details of ion cyclotron instability growth can be sensitive to local plasma conditions related to background proton distributions, and (ii) there can be preexisting waves with a specific spatial distribution, which determines occurrence and specific properties of EMIC waves depending on satellite's relative position after an enhanced Pdyn arrives.

  1. Scattering and Depolarization of Electromagnetic Waves--Full Wave Solutions.

    Science.gov (United States)

    1984-01-01

    Analysis," Proceedings of the International Union of Radio Science URSI Conference at Ciudad Universitaria , Madrid, August 1983, in press. . . 13...rough land and seat3 J. The full wave approach was also used to determine the scattering and depolarization of radio waves in irregular spheroidal struc...Full Wave Solutions," Radio Science, Vol. 17, No. 5, September-October 1982, pp. 1055-1066. 4. "Scattering and Depolarization by Rough Surfaces: Full

  2. Electromagnetic waves and electron anisotropies downstream of supercritical interplanetary shocks

    CERN Document Server

    Wilson, L B; Szabo, A; Breneman, A; Cattell, C A; Goetz, K; Kellogg, P J; Kersten, K; Kasper, J C; Maruca, B A; Pulupa, M

    2012-01-01

    We present waveform observations of electromagnetic lower hybrid and whistler waves with f_ci 1.01. Thus, the whistler mode waves appear to be driven by a heat flux instability and cause perpendicular heating of the halo electrons. The lower hybrid waves show a much weaker correlation between \\partialB and normalized heat flux magnitude and are often observed near magnetic field gradients. A third type of event shows fluctuations consistent with a mixture of both lower hybrid and whistler mode waves. These results suggest that whistler waves may indeed be regulating the electron heat flux and the halo temperature anisotropy, which is important for theories and simulations of electron distribution evolution from the sun to the earth.

  3. Electromagnetic ion cyclotron waves stimulated by modest magnetospheric compressions

    Science.gov (United States)

    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.

  4. Study of Rotating-Wave Electromagnetic Modes for Applications in Space Exploration

    Science.gov (United States)

    Velazco, J. E.

    2016-08-01

    Rotating waves are circularly polarized electromagnetic wave fields that behave like traveling waves but have discrete resonant frequencies of standing waves. In JPL's Communications Ground Systems Section (333), we are making use of this peculiar type of electromagnetic modes to develop a new generation of devices and instruments for direct applications in space exploration. In this article, we present a straightforward analysis about the phase velocity of these wave modes. A derivation is presented for the azimuthal phase velocity of transverse magnetic rotating modes inside cylindrical cavity resonators. Computer simulations and experimental measurements are also presented that corroborate the theory developed. It is shown that the phase velocity of rotating waves inside cavity resonators increases with radial position within the cavity and decreases when employing higher-order operating modes. The exotic features of rotating modes, once better understood, have the potential to enable the implementation of a plethora of new devices that range from amplifiers and frequency multipliers to electron accelerators and ion thrusters.

  5. Low-Frequency Waves in Space Plasmas

    Science.gov (United States)

    Keiling, Andreas; Lee, Dong-Hun; Nakariakov, Valery

    2016-02-01

    Low-frequency waves in space plasmas have been studied for several decades, and our knowledge gain has been incremental with several paradigm-changing leaps forward. In our solar system, such waves occur in the ionospheres and magnetospheres of planets, and around our Moon. They occur in the solar wind, and more recently, they have been confirmed in the Sun's atmosphere as well. The goal of wave research is to understand their generation, their propagation, and their interaction with the surrounding plasma. Low-frequency Waves in Space Plasmas presents a concise and authoritative up-to-date look on where wave research stands: What have we learned in the last decade? What are unanswered questions? While in the past waves in different astrophysical plasmas have been largely treated in separate books, the unique feature of this monograph is that it covers waves in many plasma regions, including: Waves in geospace, including ionosphere and magnetosphere Waves in planetary magnetospheres Waves at the Moon Waves in the solar wind Waves in the solar atmosphere Because of the breadth of topics covered, this volume should appeal to a broad community of space scientists and students, and it should also be of interest to astronomers/astrophysicists who are studying space plasmas beyond our Solar System.

  6. An attenuation Layer for Electromagnetic Shielding in X- Band Frequency

    Directory of Open Access Journals (Sweden)

    vida Zaroushani

    2015-06-01

    Full Text Available Uncontrolled exposure to X-band frequency leads to health damage. One of the principles of radiation protection is shielding. But, conventional shielding materials have disadvantages. Therefore, studies of novel materials, as an alternative to conventional shielding materials, are required to obtain new electromagnetic shielding material. Therefore, this study investigated the electromagnetic shielding of two component epoxy thermosetting resin for the X - band frequency with workplace approach. Two components of epoxy resin mixed according to manufacturing instruction with the weight ratio that was 100:10 .Epoxy plates fabricated in three different thicknesses (2, 4 and 6mm and shielding effectiveness measured by Vector Network Analyzer. Then, shielding effectiveness measured by the scattering parameters.The results showed that 6mm thickness of epoxy had the highest and 2mm had the lowest average of shielding effectiveness in X-band frequency that is 4.48 and 1.9 dB, respectively. Also, shielding effectiveness increased by increasing the thickness. But this increasing is useful up to 4mm. Percentage shielding effectiveness of attenuation for 6, 4 and 2mm thicknesses is 64.35%, 63.31% and 35.40%. Also, attenuation values for 4mm and 6mm thicknesses at 8.53 GHz and 8.52 GHz frequency are 77.15% and 82.95%, respectively, and can be used as favourite shields for the above frequency. 4mm-Epoxy is a suitable candidate for shielding application in X-band frequency range but, in the lower section, 6mm thickness is recommended. Finely, the shielding matrix can be used for selecting the proper thickness for electromagnetic shielding in X- Band frequency.

  7. Electromagnetism

    CERN Multimedia

    Without the electromagnetic force, you would not be solid. The atoms of your body are held together by electromagnetism: negatively charged electrons are held around the positively charged nucleus. Atoms share electrons to form molecules, so building up the structure of matter. As its name suggests, electromagnetism has a double nature: a moving electric charge creates a magnetic field. This intimate connection between electricity and magnetism was described by James Maxwell in 1864. The electromagnetic force can be both positive and negative : opposite charges attract, whereas like charges repel. Electromagnetic radiation, such as radio, microwaves, light and X-rays, is emitted by charges when they are made to move. For example, an oscillating current in a wire emits radio waves. Text for the interactive: Why do the needles move when you switch on the current ?

  8. [A Compact Source of Terahertz Radiation Based on Interaction of Electrons in à Quantum Well with an Electromagnetic Wave of a Corrugated Waveguide].

    Science.gov (United States)

    Shchurova, L Yu; Namiot, V A; Sarkisyan, D R

    2015-01-01

    Coherent sources of electromagnetic waves in the terahertz frequency range are very promising for various applications, including biology and medicine. In this paper we propose a scheme of a compact terahertz source, in which terahertz radiation is generated due to effective interaction of electrons in a quantum well with an electromagnetic wave of a corrugated waveguide. We have shown that the generation of electromagnetic waves with a frequency of 1012 sec(-1) and an output power of up to 25. mW is possible in the proposed scheme.

  9. Dynamic control of asymmetric electromagnetic wave transmission by active chiral metamaterial

    Science.gov (United States)

    Chen, Ke; Feng, Yijun; Cui, Li; Zhao, Junming; Jiang, Tian; Zhu, Bo

    2017-02-01

    The asymmetric transmission of electromagnetic (EM) wave can be fully manipulated by chiral metamaterials, but little can achieve real-time and high efficient tunability due to challenges in practically deployable solutions. Here, we proposed a new scheme for flexibly and dynamically controlling the asymmetric EM wave transmission at microwave frequencies using planar metamaterial of deep subwavelength thickness incorporated with active components of PIN diodes. The asymmetric transmission of linearly polarized EM wave exhibits a high efficiency and a pronounced real-time continuous tunability controlled by the external stimulation of voltage biasing. In addition, the asymmetric transmission effect can be well preserved at large oblique incident angle up to ±70°. The design principle and EM performance are validated by both full wave simulations and experimental measurements. Such dynamically controllable chiral metamaterial may provide robust and flexible approach to manipulate EM wave propagation, as well as to facilitate EM device integration to create diverse functionalities.

  10. Dynamic control of asymmetric electromagnetic wave transmission by active chiral metamaterial

    Science.gov (United States)

    Chen, Ke; Feng, Yijun; Cui, Li; Zhao, Junming; Jiang, Tian; Zhu, Bo

    2017-01-01

    The asymmetric transmission of electromagnetic (EM) wave can be fully manipulated by chiral metamaterials, but little can achieve real-time and high efficient tunability due to challenges in practically deployable solutions. Here, we proposed a new scheme for flexibly and dynamically controlling the asymmetric EM wave transmission at microwave frequencies using planar metamaterial of deep subwavelength thickness incorporated with active components of PIN diodes. The asymmetric transmission of linearly polarized EM wave exhibits a high efficiency and a pronounced real-time continuous tunability controlled by the external stimulation of voltage biasing. In addition, the asymmetric transmission effect can be well preserved at large oblique incident angle up to ±70°. The design principle and EM performance are validated by both full wave simulations and experimental measurements. Such dynamically controllable chiral metamaterial may provide robust and flexible approach to manipulate EM wave propagation, as well as to facilitate EM device integration to create diverse functionalities. PMID:28202903

  11. Dynamic control of asymmetric electromagnetic wave transmission by active chiral metamaterial.

    Science.gov (United States)

    Chen, Ke; Feng, Yijun; Cui, Li; Zhao, Junming; Jiang, Tian; Zhu, Bo

    2017-02-16

    The asymmetric transmission of electromagnetic (EM) wave can be fully manipulated by chiral metamaterials, but little can achieve real-time and high efficient tunability due to challenges in practically deployable solutions. Here, we proposed a new scheme for flexibly and dynamically controlling the asymmetric EM wave transmission at microwave frequencies using planar metamaterial of deep subwavelength thickness incorporated with active components of PIN diodes. The asymmetric transmission of linearly polarized EM wave exhibits a high efficiency and a pronounced real-time continuous tunability controlled by the external stimulation of voltage biasing. In addition, the asymmetric transmission effect can be well preserved at large oblique incident angle up to ±70°. The design principle and EM performance are validated by both full wave simulations and experimental measurements. Such dynamically controllable chiral metamaterial may provide robust and flexible approach to manipulate EM wave propagation, as well as to facilitate EM device integration to create diverse functionalities.

  12. Electromagnetic absorption properties of flowerlike cobalt composites at microwave frequencies

    Institute of Scientific and Technical Information of China (English)

    Liu Tao; Zhou Pei-Heng; Liang Di-Fei; Deng Long-Jiang

    2012-01-01

    In this work,we report the electromagnetic absorption(EMA)properties of composites consisting of micrometersized cobalt with flowerlike architecture synthesized by a facile hydrothermal reduction method.Compared with the conventional spherical Co-paraffin composites,the flowerlike Co-paraffin composites are favorable with respect to EMA performance in the low frequency region,ascribing interfacial polarization loss and Ohmic loss to the improvement in the impedance match.

  13. Ultra-low-frequency dust-electromagnetic modes in self-gravitating magnetized dusty plasmas

    Indian Academy of Sciences (India)

    A K Banerjee; M N Alam; A A Mamun

    2001-05-01

    Obliquely propagating ultra-low-frequency dust-electromagnetic waves in a self-gravitating, warm, magnetized, two fluid dusty plasma system have been investigated. Two special cases, namely, dust-Alfvén mode propagating parallel to the external magnetic field and dust-magnetosonic mode propagating perpendicular to the external magnetic field have also been considered. It has been shown that effects of self-gravitational field, dust fluid temperature, and obliqueness significantly modify the dispersion properties of these ultra-low-frequency dust-electromagnetic modes. It is also found that in parallel propagating dust-Alfvén mode these effects play no role, but in obliquely propagating dust-Alfvén mode or perpendicular propagating dust-magnetosonic mode the effect of self-gravitational field plays destabilizing role whereas the effect of dust/ion fluid temperature plays stabilizing role.

  14. Predicting Electromagnetic Signatures of Gravitational Wave Sources

    Science.gov (United States)

    D'Orazio, Daniel John

    This dissertation investigates the signatures of electromagnetic radiation that may accompany two specific sources of gravitational radiation: the inspiral and merger of massive black hole binaries (MBHBs) in galactic nuclei, and the coalescence of black hole neutron star (BHNS) pairs. Part I considers the interaction of MBHBs, at sub-pc separations, with a circumbinary gas disk. Accretion rates onto the MBHB are calculated from two-dimensional hydrodynamical simulations as a function of the relative masses of the black holes. The results are applied to interpretation of the recent, sub-pc separation MBHB candidate in the nucleus of the periodically variable Quasar PG 1302-102. We advance an interpretation of the variability observed in PG 1302-102 as being caused by Doppler-boosted emission sourced by the orbital velocity of the smaller black hole in a MBHB with disparate relative masses. Part II considers BHNS binaries in which the black hole is large enough to swallow the neutron star whole before it is disrupted. As the pair nears merger, orbital motion of the black hole through the magnetosphere of the neutron star generates an electromotive force, a black-hole-battery, which, for the strongest neutron star magnetic field strengths, could power luminosities large enough to make the merging pair observable out to cosmic distances. Relativistic solutions for vacuum fields of a magnetic dipole near a horizon are given, and a mechanism for harnessing the power of the black-hole-battery is put forth in the form of a fireball emitting in hard X-rays to gamma-rays.

  15. Frequency conversion of probe wave produced by 2D interaction with relativistic ionization front

    Institute of Scientific and Technical Information of China (English)

    Yan Li-Xin; Zhang Yong-Sheng; Liu Jing-Ru; Lü Min

    2005-01-01

    Frequency conversion of probe electromagnetic wave induced by relativistic ionization front is theoretically analysed based on ray-tracing equations in different regimes. Downshifting as well as upshifting in frequency produced by the front is predicted. The reflected and transmitted angles can be also dramatically changed in certain cases.

  16. Geometric phase coded metasurface: from polarization dependent directive electromagnetic wave scattering to diffusion-like scattering.

    Science.gov (United States)

    Chen, Ke; Feng, Yijun; Yang, Zhongjie; Cui, Li; Zhao, Junming; Zhu, Bo; Jiang, Tian

    2016-10-24

    Ultrathin metasurface compromising various sub-wavelength meta-particles offers promising advantages in controlling electromagnetic wave by spatially manipulating the wavefront characteristics across the interface. The recently proposed digital coding metasurface could even simplify the design and optimization procedures due to the digitalization of the meta-particle geometry. However, current attempts to implement the digital metasurface still utilize several structural meta-particles to obtain certain electromagnetic responses, and requiring time-consuming optimization especially in multi-bits coding designs. In this regard, we present herein utilizing geometric phase based single structured meta-particle with various orientations to achieve either 1-bit or multi-bits digital metasurface. Particular electromagnetic wave scattering patterns dependent on the incident polarizations can be tailored by the encoded metasurfaces with regular sequences. On the contrast, polarization insensitive diffusion-like scattering can also been successfully achieved by digital metasurface encoded with randomly distributed coding sequences leading to substantial suppression of backward scattering in a broadband microwave frequency. The proposed digital metasurfaces provide simple designs and reveal new opportunities for controlling electromagnetic wave scattering with or without polarization dependence.

  17. Response of thermal ions to electromagnetic ion cyclotron waves

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, B.J. [Johns Hopkins Univ., Laurel, MD (United States); Fuselier, S.A. [Lockheed Palo Alto Research Lab., CA (United States)

    1994-10-01

    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. The authors examine H{sup +} and He{sup +} distribution functions from {approx} 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 perpendicularly heated ion distributions. For protons the perpendicular temperature increase is modest, about 5 eV, and is always observed at 90{degrees} pitch angles. This is consistent with a nonresonant interaction near the equator. By contrast, He{sup +} temperatures during EMIC wave events averaged 35 eV and sometimes exceeded 100 eV, indicating stronger interaction with the waves. Furthermore, heated He{sup +} ions have X-type distributions with maximum fluxes occurring at pitch angles intermediate between field-aligned and perpendicular directions. The X-type He{sup +} distributions are consistent with a gyroresonant interaction off the equator. The concentration of He{sup +} relative to H{sup +} is found to correlate with EMIC wave activity, but it is suggested that the preferential heating of He{sup +} accounts for the apparent increase in relative He{sup +} concentration by increasing the proportion of He{sup +} detected by the ion instrument. 35 refs., 8 figs., 1 tab.

  18. Characterization of porous construction materials using electromagnetic radar wave

    Science.gov (United States)

    Lai, Wallace Wai Lok

    This thesis reports the effort of characterizing three porous construction materials (i.e. concrete, asphalt and soils) and the establishment and formulation of novel unified constitutive models by utilizing electromagnetic (EM) radar wave. An important outcome of this research is that the studied materials were assigned successfully into their rightful positions corresponding to the different regimes governed by three EM wave properties and two engineering/geological properties of the materials. The former refers to the real part of complex dielectric permittivity (epsilon'), energy attenuation and peak-frequency drift. The latter refers to porosity and permeability determined with forward models or conventional testing techniques. In soil and asphalt, the material characterization was achieved by a novel inhouse developed method called Cyclic Moisture Variation Technique (CMVT). The technique is termed cyclic because the porous materials were subjected to change from partially saturated states to fully saturated state (i.e. permeation), and vice versa (i.e. de-watering). With CMVT, water was used as an enhancer or a tracer to differentiate the studied materials which are otherwise difficult when they are dry. Soils and asphalt with different textures were characterized by different curve families exhibited in the relationship between epsilon' and degrees of water saturation (SW). In particular, these curve families were divided into three regions: slow-climbing region in very low SW, fast-climbing region in intermediate SW and another slow-climbing region at high S W. When data obtained from the permeation and de-watering cycles was compared, dielectric hysteresis was observed, but rarely reported in the field of ground penetrating radar (GPR). Different curing histories affect both porosity and pore size distribution within mature concrete. By injecting pressurized water into concrete specimens, different concrete curing histories was back-tracked through the

  19. Spatial transformation-enabled electromagnetic devices: from radio frequencies to optical wavelengths

    OpenAIRE

    Jiang, Zhi Hao; Turpin, Jeremy P.; Morgan, Kennith; Lu, Bingqian; Werner, Douglas H.

    2015-01-01

    Transformation optics provides scientists and engineers with a new powerful design paradigm to manipulate the flow of electromagnetic waves in a user-defined manner and with unprecedented flexibility, by controlling the spatial distribution of the electromagnetic properties of a medium. Using this approach, over the past decade, various previously undiscovered physical wave phenomena have been revealed and novel electromagnetic devices have been demonstrated throughout the electromagnetic spe...

  20. Effects of Millimeter-Wave Electromagnetic Radiation on the Experimental Model of Migraine.

    Science.gov (United States)

    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.

  1. Electromagnetic wave theory for boundary-value problems an advanced course on analytical methods

    CERN Document Server

    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.

  2. Nonlinear propagation of coupled electromagnetic waves in a circular cylindrical waveguide

    Science.gov (United States)

    Valovik, D. V.; Smol'kin, E. Yu.

    2017-08-01

    The problem of the propagation of coupled surface electromagnetic waves in a two-layer cylindrical circular waveguide filled with an inhomogeneous nonlinear medium is considered. A nonlinear coupled TE-TM wave is characterized by two (independent) frequencies ωe and ωm and two propagation constants {\\widehat γ _e} and {\\widehat γ _m}. The physical problem reduces to a nonlinear two-parameter eigenvalue problem for a system of nonlinear ordinary differential equations. The existence of eigenvalues ({\\widehat γ _e}, {\\widehat γ _m}) in proven and intervals of their localization are determined.

  3. The focusing effect of electromagnetic waves in two-dimensional photonic crystals with gradually varying lattice constant

    Directory of Open Access Journals (Sweden)

    F Bakhshi Garmi

    2016-02-01

    Full Text Available In this paper we studied the focusing effect of electromagnetic wave in the two-dimensional graded photonic crystal consisting of Silicon rods in the air background with gradually varying lattice constant. The results showed that graded photonic crystal can focus wide beams on a narrow area at frequencies near the lower edge of the band gap, where equal frequency contours are not concave. For calculation of photonic band structure and equal frequency contours, we have used plane wave expansion method and revised plane wave expansion method, respectively. The calculation of the electric and magnetic fields was performed by finite difference time domain method.

  4. High-Frequency Rayleigh-Wave Method

    Institute of Scientific and Technical Information of China (English)

    Jianghai Xia; Richard D Millerg; Xu Yixian; Luo Yinhe; Chen Chao; Liu Jiangping; Julian Ivanov; Chong Zeng

    2009-01-01

    High-frequency (≥2 Hz) Rayleigh-wave data acquired with a multichannei recording sys-tem have been utilized to determine shear (S)-wave velocities in near-surface geophysics since the early 1980s. This overview article discusses the main research results of high-frequency surface-wave tech-niques achieved by research groups at the Kansas Geological Survey and China University of Geosciences in the last 15 years. The multichannel analysis of surface wave (MASW) method is a nou-iuvasive acoustic approach to estimate near-surface S-wave velocity. The differences between MASW results and direct borehole measurements are approximately 15% or less and random. Studies show that simultaneous inversion with higher modes and the fundamental mode can increase model resolution and an investigation depth. The other important seismic property, quality factor (Q), can also be estimated with the MASW method by inverting attenuation coefficients of Rayleigh waves. An inverted model (S-wave velocity or Q) obtained using a damped least-squares method can be assessed by an optimal damping vector in a vicinity of the inverted model determined by an objective function, which is the trace of a weighted sum of model-resolution and model-covariance matrices. Current developments include modeling high-frequency Rayleigh-waves in near-surface media, which builds a foundation for shallow seismic or Rayleigh-wave inversion in the time-offset domain; imaging dispersive energy with high resolution in the frequency-velocity domain and possibly with data in an arbitrary acquisition geometry, which opens a door for 3D surface-wave techniques; and successfully separating surface-wave modes, which provides a valuable tool to perform S-wave velocity profiling with high-horizontal resolution.

  5. Detecting electromagnetic cloaks using backward-propagating waves

    KAUST Repository

    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.

  6. Attractors and chaos of electron dynamics in electromagnetic standing wave

    CERN Document Server

    Esirkepov, Timur Zh; Koga, James K; Kando, Masaki; Kondo, Kiminori; Rosanov, Nikolay N; Korn, Georg; Bulanov, Sergei V

    2014-01-01

    The radiation reaction radically influences the electron motion in an electromagnetic standing wave formed by two super-intense counter-propagating laser pulses. Depending on the laser intensity and wavelength, either classical or quantum mode of radiation reaction prevail, or both are strong. When radiation reaction dominates, electron motion evolves to limit cycles and strange attractors. This creates a new framework for high energy physics experiments on an interaction of energetic charged particle beams and colliding super-intense laser pulses.

  7. Short wave breaking effects on low frequency waves

    NARCIS (Netherlands)

    Daly, C.; Roelvink, J.A.; Van Dongeren, A.; Van Thiel de Vries, J.S.M.; McCall, R.T.

    2010-01-01

    The effect of short wave breaking on low frequency waves is investigated using two breaker formulations implemented in a time-dependent numerical model (XBeach): (1) an advective-deterministic approach (ADA) and (2) the probabilistic breaker formulation of Roelvink (1993). Previous research has show

  8. High frequency electromagnetic interference shielding magnetic polymer nanocomposites

    Science.gov (United States)

    He, Qingliang

    Electromagnetic interference is one of the most concerned pollution and problem right now since more and more electronic devices have been extensively utilized in our daily lives. Besides the interference, long time exposure to electromagnetic radiation may also result in severe damage to human body. In order to mitigate the undesirable part of the electromagnetic wave energy and maintain the long term sustainable development of our modern civilized society, new technology development based researches have been made to solve this problem. However, one of the major challenges facing to the electromagnetic interference shielding is the relatively low shielding efficiency and the high cost as well as the complicated shielding material manufacture. From the materials science point of view, the key solutions to these challenges are strongly depended on the breakthrough of the current limit of shielding material design and manufacture (such as hierarchical material design with controllable and predictable arrangement in nanoscale particle configuration via an easy in-situ manner). From the chemical engineering point of view, the upgrading of advanced material shielding performance and the enlarged production scale for shielding materials (for example, configure the effective components in the shielding material in order to lower their usage, eliminate the "rate-limiting" step to enlarge the production scale) are of great importance. In this dissertation, the design and preparation of morphology controlled magnetic nanoparticles and their reinforced polypropylene polymer nanocomposites will be covered first. Then, the functionalities of these polymer nanocomposites will be demonstrated. Based on the innovative materials design and synergistic effect on the performance advancement, the magnetic polypropylene polymer nanocomposites with desired multifunctionalities are designed and produced targeting to the electromagnetic interference shielding application. In addition

  9. Two-Component Multi-Parameter Time-Frequency Electromagnetics

    Institute of Scientific and Technical Information of China (English)

    HuangZhou; DongWeibin; HeTiezhi

    2003-01-01

    The two-component multi-parameter time-frequency electromagnetic method, used for the development of oilfields,makes use of both the traditional individual conductivity parameters of oil-producing layers and the dispersion information of the conductivity, i.e., the induced polarization parameter. The frequency-domain dispersion data is used to delineate the contacts between oil and water and the time domain dBz/dt component is used to estimate the depths to the un-known reservoirs so as to offer significant data in many aspects for oil exploration and detection.

  10. Fabrication and characterization of a low frequency electromagnetic energy harvester

    Institute of Scientific and Technical Information of China (English)

    Abu Riduan Md.Foisal; Gwiy-Sang Chung

    2012-01-01

    This paper presents the fabrication and characterization of an AA size electromagnetic energy transducer based on vibration.A magnetic spring technique is used to scavenge energy from low frequency external vibration.The output of the harvester is maximized by optimizing the mass of moving and fixed magnets,coil width,coil position and load resistance through a comprehensive experimental analysis.The prototype can generate an open circuit voltage of 3.961 V and 1.18 mW average power at a load resistance of 97 Ω with 9 Hz resonance frequency and 0.5 mm displacement.

  11. DATA ACQUISITION AND ANALYSIS OF LOW FREQUENCY ELECTROMAGNETIC FIELD

    Directory of Open Access Journals (Sweden)

    PETRICA POPOV

    2016-06-01

    Full Text Available In recent years more and more studies have shown that, the low frequency field strength (particularly magnetic, 50 / 60Hz are a major risk factor; according to some specialists - even more important as the radiation field. As a result, the personnel serving equipment and facilities such as: electric generators, synchronous, the motors, the inverters or power transformers is subjected continually to intense fields, in their vicinity, with possible harmful effects in the long term by affecting metabolism cell, espectively, the biological mechanisms.Therefore, finding new methods and tools for measurement and analysis of low frequency electromagnetic fields may lead to improved standards for exposure limits of the human body.

  12. 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.

  13. 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.

  14. Proton acceleration by circularly polarized traveling electromagnetic wave

    Directory of Open Access Journals (Sweden)

    Amol Holkundkar

    2012-09-01

    Full Text Available The acceleration of charged particles, producing collimated monoenergetic beams, over short distances holds the promise to offer new tools in medicine and diagnostics. Here, we consider a possible mechanism for accelerating protons to high energies by using a phase modulated circularly polarized electromagnetic wave propagating along a constant magnetic field. It is observed that a plane wave with dimensionless amplitude of 0.1 is capable to accelerate a 1 keV proton to 386 MeV under optimum conditions. Finally, we discuss possible limitations of the acceleration scheme.

  15. Proton acceleration by circularly polarized traveling electromagnetic wave

    CERN Document Server

    Holkundkar, A; Marklund, M

    2012-01-01

    The acceleration of charged particles, producing collimated mono-energetic beams, over short distances holds the promise to offer new tools in medicine and diagnostics. Here, we consider a possible mechanism for accelerating protons to high energies by using a phase-modulated circularly polarized electromagnetic wave propagating along a constant magnetic field. It is observed that a plane wave with dimensionless amplitude of 0.1 is capable to accelerate a 1 KeV proton to 386 MeV under optimum conditions. Finally we discuss possible limitations of the acceleration scheme.

  16. Electromagnetic ion cyclotron waves observed in the plasma depletion layer

    Science.gov (United States)

    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.

  17. 典型甚低频电磁波对辐射带高能电子的散射损失效应%Diffusing loss effects of radiation b elt energetic electrons caused by typical very low frequency electromagnetic wave

    Institute of Scientific and Technical Information of China (English)

    罗旭东; 牛胜利; 左应红

    2015-01-01

    辐射带中高能电子与空间甚低频电磁波由于波粒共振相互作用发生投掷角散射,进而沉降入稠密大气而损失.为研究甚低频电磁波对辐射带中高能电子的散射作用机制,本文基于准线性扩散理论,利用库仑作用和波粒共振相互作用扩散系数的物理模型,得到了两组典型甚低频电磁波与高能电子波粒共振相互作用的赤道投掷角弹跳周期平均扩散系数,并分析了甚低频电磁波共振散射作用与大气库仑散射作用对不同磁壳及不同能量的辐射带电子扩散损失的影响规律.以磁壳参数L=2.2,能量E =0.5 MeV的辐射带电子作为算例,采用有限差分方法数值求解扩散方程,计算分析了电子单向通量和全向通量随时间的沉降损失演化规律.研究结果表明:当电子能量大于0.5 MeV,磁壳参数大于1.6时,甚低频电磁波的共振散射作用显著;随着磁壳参数或电子能量的增大,斜传播甚低频电磁波引起的高阶共振相互作用越来越大;电子全向通量近似随时间呈指数函数形式衰减.%Radiation belt energetic electrons can interact with very low frequency (VLF) electromagnetic wave due to wave-particle resonance; then the particles are imposed to enter into the loss cone and sink to dense atmosphere resulting from changing of its pitch angle. To investigate the diffusion mechanism of interaction of VLF electromagnetic wave with radiation belt energetic electrons, according to quasi-linear diffusion theory, in this paper we use a physical model to calculate diffusion coefficients of Coulomb scatting and wave-particle resonance interaction. Bounce-averaged pitch angle diffusion coefficients of energetic electrons due to the interaction of wave-particle resonance with two groups of VLF electromagnetic waves are obtained. The influence of interaction caused by VLF electromagnetic wave and Coulomb scatting on diffusion of radiation belt energetic electrons for

  18. Descriptive Study of Electromagnetic Wave Distribution for Various Seating Positions: Using Digital Textbooks

    Science.gov (United States)

    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…

  19. Descriptive Study of Electromagnetic Wave Distribution for Various Seating Positions: Using Digital Textbooks

    Science.gov (United States)

    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…

  20. Numerical simulation of azimuth electromagnetic wave tool response based on self-adaptive FEM

    Science.gov (United States)

    Li, Hui; Shen, Yi-Ze

    2017-07-01

    Azimuth electromagnetic wave is a new type of electromagnetic prospecting technology. It can detect weak electromagnetic wave signal and realize real-time formation conductivity imaging. For effectively optimizing measurement accuracy of azimuth electromagnetic wave imaging tool, the efficient numerical simulation algorithm is required. In this paper, self-adaptive finite element method (FEM) has been used to investigate the azimuth electromagnetic wave logging tool response by adjusting antenna array system in different geological conditions. Numerical simulation examples show the accuracy and efficiency of the method, and provide physical interpretation of amplitude attenuation and phase shift of electromagnetic wave signal. Meanwhile, the high-accuracy numerical simulation results have great value to azimuth electromagnetic wave imaging tool calibration and data interpretation.

  1. Quantifying and predicting meat and meat products quality attributes using electromagnetic waves: an overview.

    Science.gov (United States)

    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.

  2. Low-Frequency Electromagnetic Exploration for Groundwater on Mars

    Science.gov (United States)

    Grimm, Robert E.

    2002-01-01

    Water with even a small amount of dissolved solids has an electrical conductivity orders of magnitude higher than dry rock and is therefore a near-ideal exploration target on Mars for low frequency, diffusive electromagnetic methods. Models of the temperature- and frequency-dependent electrical properties of rock-ice-water mixtures are used to predict the electromagnetic response of the Martian subsurface. Detection of ice is difficult unless it is massively segregated. In contrast, liquid water profoundly affects soundings, and even a small amount of adsorbed water in the cryosphere can be detected. Subcryospheric water is readily distinguishable at frequencies as low as 100 Hz for fresh water to 10 mHz for brines. These responses can be measured using either natural or artificial sources. Ultra low frequency signals from solar wind and diurnal-heating perturbations of the ionosphere are likely, and disturbances of regional crustal magnetic fields may also be observable. Spherics, or extremely to very low frequency signals from lightning discharge, would provide optimal soundings; however, lightning may be the least likely of the possible natural sources. Among the active techniques, only the time-domain electromagnetic (TDEM) method can accommodate a closely spaced transmitter and receiver and sound to depths of hundreds of meters or more. A ground- or aircraft-based TDEM system of several kilograms can detect water to a depth of several hundred meters, and a system of tens of kilograms featuring a large, fixed, rover- or ballistically deployed loop can detect water to several kilometers depth.

  3. Cross-polarization scattering from low-frequency waves in a tandem mirror plasma

    Energy Technology Data Exchange (ETDEWEB)

    Kogi, Yuichiro; Mase, Atsushi; Bruskin, L.G.; Oyama, Naoyuki; Tokuzawa, Tokihiko; Itakura, Akiyosi; Hojo, Hitoshi; Tamano, Teruo [Tsukuba Univ., Ibaraki (Japan). Plasma Research Center

    1997-05-01

    Cross-polarization scattering (CPS) diagnostic was applied to the central-cell plasma of the GAMMA 10 tandem mirror in order to study electromagnetic plasma waves with frequencies of less than 200 kHz. In the CPS process, an incident ordinary (extraordinary) wave is converted to an extraordinary (ordinary) wave by magnetic fluctuations in a plasma. The converted wave propagates through the cutoff layer and reaches the opposite diagnostic port. The experimental data suggest that the power spectral density of the CPS signal satisfies the Bragg condition, while the reflectometer detects the waves near the cutoff layer where the wave number cannot be resolved. (author)

  4. [Analysis of Electric Stress in Human Head in High-frequency Low-power Electromagnetic Environment].

    Science.gov (United States)

    Zhou, Yongjun; Zhang, Hui; Niu, Zhongqi

    2015-04-01

    Action of electromagnetic radiation exerting on human body has been a concerned issue for people. Because electromagnetic waves could generate an electric stress in a discontinuous medium, we used the finite difference time domain (FDTD) as calculation methods to calculate the electric stress and its distribution in human head caused by high-frequency low-power electromagnetic environment, which was generated by dual-band (900 MHz and 1 800 MHz) PIFA antennas with radiated power 1 W, and we then performed the safety evaluation of cell phone radiation from the angle whether the electric stress further reached the human hearing threshold. The result showed that there existed the electric stress at the interface of different permittivity organization caused by the two kinds of high-frequency low-power electromagnetic environment and the maximum electric stress was located at the interface between skin and air of the phone side, and the electric stress peak at skull did not reach the threshold of auditory caused by bone tissue conduction so that it can not produce auditory effects.

  5. The wave buoy analogy - estimating high-frequency wave excitations

    DEFF Research Database (Denmark)

    Nielsen, Ulrik Dam

    2008-01-01

    The paper deals with the wave buoy analogy where a ship is considered as a wave buoy, so that measured ship responses are used as a basis to estimate wave spectra and associated sea state parameters. The study presented follows up on a previous paper, Nielsen [Nielsen UD. Response-based estimation...... processes are carried out in the present paper; however with one of the responses being the relative motion which is a type of response that is sensitive to high-frequency excitations. Based on the present study it is shown that by including the relative motion, the frequency-wise energy distribution can...

  6. Scattering of radio frequency waves by turbulence in fusion plasmas

    Science.gov (United States)

    Ram, Abhay K.

    2016-10-01

    In tokamak fusion plasmas, coherent fluctuations in the form of blobs or filaments and incoherent fluctuations due to turbulence are routinely observed in the scrape-off layer. Radio frequency (RF) electromagnetic waves, excited by antenna structures placed near the wall of a tokamak, have to propagate through the scrape-off layer before reaching the core of the plasma. While the effect of fluctuations on RF waves has not been quantified experimentally, there are telltale signs, arising from differences between results from simulations and from experiments, that fluctuations can modify the spectrum of RF waves. Any effect on RF waves in the scrape-off layer can have important experimental consequences. For example, electron cyclotron waves are expected to stabilize the deleterious neoclassical tearing mode (NTM) in ITER. Spectral and polarization changes due to scattering will modify the spatial location and profile of the current driven by the RF waves, thereby affecting the control of NTMs. Pioneering theoretical studies and complementary computer simulations have been pursued to elucidate the impact of fluctuations on RF waves. From the full complement of Maxwell's equations for cold, magnetized plasmas, it is shown that the Poynting flux in the wake of filaments develops spatial structure due to diffraction and shadowing. The uniformity of power flow into the plasma is affected by side-scattering, modifications to the wave spectrum, and coupling to plasma waves other than the incident RF wave. The Snell's law and the Fresnel equations have been reformulated within the context of magnetized plasmas. They are distinctly different from their counterparts in scalar dielectric media, and reveal new and important physical insight into the scattering of RF waves. The Snell's law and Fresnel equations are the basis for the Kirchhoff approximation necessary to determine properties of the scattered waves. Furthermore, this theory is also relevant for studying back

  7. Non linear dynamic of Langmuir and electromagnetic waves in space plasmas; Dinamica nao linear de ondas de Langmuir e eletromagneticas em plasmas espaciais

    Energy Technology Data Exchange (ETDEWEB)

    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

  8. Fabrication of Terahertz Wave Resonators with Alumina Diamond Photonic Crystals for Frequency Amplification in Water Solvents

    Energy Technology Data Exchange (ETDEWEB)

    Ohta, N; Niki, T; Kirihara, S, E-mail: n-ohta@jwri.osaka-u.ac.jp [Smart Processing Research Center, Joining and Welding Research Institute, Osaka University, Ibaraki, Osaka, 567-0047 (Japan)

    2011-05-15

    Terahertz wave resonators composed of alumina photonic crystals with diamond lattice structures were designed and fabricated by using micro stereolithography. These three dimensional periodic structures can reflect perfectly electromagnetic waves through Bragg diffraction. A micro glass cell including water solutions was put between the photonic crystals as a novel resonance sensor with terahertz frequency range. The localized and amplified waves in the resonators were measured by a spectroscopy, and visualized by theoretical simulations.

  9. Reflection of Electromagnetic Waves by a Nonuniform Plasma Layer Covering a Metal Surface

    Institute of Scientific and Technical Information of China (English)

    GAO Hong-Mei; FA Peng-Ting

    2008-01-01

    Reflection coefficients of electromagnetic waves in a nonuniform plasma layer with electrons, positive ions and negative ions, covering a metal surface are investigated by using the finite-difference-time-domain method. It is shown that the reflection coefficients are influenced greatly by the density gradient on the layer edge, layer thickness and electron proportion, i.e., the effect of the negative ions. It is also found that low reflection or high attenuation can be reached by properly choosing high electron proportion, thick plasma layer, and smooth density gradient in the low frequency regime, but sharp density gradient in the high frequency regime.

  10. Influence of electromagnetic signal of antibiotics excited by low-frequency pulsed electromagnetic fields on growth of Escherichia coli.

    Science.gov (United States)

    Ke, Yin-Lung; Chang, Fu-Yu; Chen, Ming-Kun; Li, Shun-Lai; Jang, Ling-Sheng

    2013-01-01

    Energy medicine (EM) provides a new medical choice for patients, and its advantages are the noninvasive detection and nondrug treatment. An electromagnetic signal, a kind of EM, induced from antibiotic coupling with weak, extremely low-frequency pulsed electromagnetic fields (PEMFs) is utilized for investigating the growth speed of Escherichia coli (E. coli). PEMFs are produced by solenoidal coils for coupling the electromagnetic signal of antibiotics (penicillin). The growth retardation rate (GRR) of E. coli is used to investigate the efficacy of the electromagnetic signal of antibiotics. The E. coli is cultivated in the exposure of PEMFs coupling with the electromagnetic signal of antibiotics. The maximum GRR of PEMFs with and without the electromagnetic signal of antibiotics on the growth of E. coli cells in the logarithmic is 17.4 and 9.08%, respectively. The electromagnetic signal of antibiotics is successfully coupled by the electromagnetic signal coupling instrument to affect the growth of E. coli. In addition, the retardation effect on E. coli growth can be improved of by changing the carrier frequency of PEMFs coupling with the electromagnetic signal of antibiotics. GRR caused by the electromagnetic signal of antibiotics can be fixed by a different carrier frequency in a different phase of E. coli growth.

  11. Loop heating by D.C. electric current and electromagnetic wave emissions simulated by 3-D EM particle zone

    Science.gov (United States)

    Sakai, J. I.; Zhao, J.; Nishikawa, K.-I.

    1994-01-01

    We have shown that a current-carrying plasma loop can be heated by magnetic pinch driven by the pressure imbalance between inside and outside the loop, using a 3-dimensional electromagnetic (EM) particle code. Both electrons and ions in the loop can be heated in the direction perpendicular to the ambient magnetic field, therefore the perpendicular temperature can be increased about 10 times compared with the parallel temperature. This temperature anisotropy produced by the magnetic pinch heating can induce a plasma instability, by which high-frequency electromagnetic waves can be excited. The plasma current which is enhanced by the magnetic pinch can also excite a kinetic kink instability, which can heat ions perpendicular to the magnetic field. The heating mechanism of ions as well as the electromagnetic emission could be important for an understanding of the coronal loop heating and the electromagnetic wave emissions from active coronal regions.

  12. Ring Current Ion Coupling with Electromagnetic Ion Cyclotron Waves

    Science.gov (United States)

    Khazanov, George V.

    2002-01-01

    A new ring current global model has been developed for the first time that couples the system of two kinetic equations: one equation describes the ring current (RC) ion dynamic, and another equation describes wave evolution of electromagnetic ion cyclotron waves (EMIC). The coupled model is able to simulate, for the first time self-consistently calculated RC ion kinetic and evolution of EMIC waves that propagate along geomagnetic field lines and reflect from the ionosphere. Ionospheric properties affect the reflection index through the integral Pedersen and Hall coductivities. The structure and dynamics of the ring current proton precipitating flux regions, intensities of EMIC, global RC energy balance, and some other parameters will be studied in detail for the selected geomagnetic storms. The space whether aspects of RC modelling and comparison with the data will also be discussed.

  13. 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)

  14. Nonlinear Electromagnetic Waves in a Degenerate Electron-Positron Plasma

    Science.gov (United States)

    El-Labany, S. K.; El-Taibany, W. F.; El-Samahy, A. E.; Hafez, A. M.; Atteya, A.

    2015-08-01

    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.

  15. Inversion of an Atomic Wave Packet in a Circularly Polarized Electromagnetic Wave

    Institute of Scientific and Technical Information of China (English)

    ZENG Gao-Jian

    2001-01-01

    We study behavior of an atomic wave packet in a circularly polarized electromagnetic wave, and particularly calculate the atomic inversion of the wave packet. A general method of calculation is presented. The results are interesting. For example, if the wave packet is very narrow or/and the interaction is very strong, no matter the atom is initially in its ground state or excited state, the atomic inversion approaches zero as time approaches infinity. If the atom is initially in its ground state and excited state with the probability 1/2 respectively, and if the momentum density is an even function, then the atomic inversion equals zero at any time.``

  16. Finite element modeling of electromagnetic fields and waves using NASTRAN

    Science.gov (United States)

    Moyer, E. Thomas, Jr.; Schroeder, Erwin

    1989-01-01

    The various formulations of Maxwell's equations are reviewed with emphasis on those formulations which most readily form analogies with Navier's equations. Analogies involving scalar and vector potentials and electric and magnetic field components are presented. Formulations allowing for media with dielectric and conducting properties are emphasized. It is demonstrated that many problems in electromagnetism can be solved using the NASTRAN finite element code. Several fundamental problems involving time harmonic solutions of Maxwell's equations with known analytic solutions are solved using NASTRAN to demonstrate convergence and mesh requirements. Mesh requirements are studied as a function of frequency, conductivity, and dielectric properties. Applications in both low frequency and high frequency are highlighted. The low frequency problems demonstrate the ability to solve problems involving media inhomogeneity and unbounded domains. The high frequency applications demonstrate the ability to handle problems with large boundary to wavelength ratios.

  17. ULF wave electromagnetic energy flux into the ionosphere: Joule heating implications

    Science.gov (United States)

    Hartinger, M. D.; Moldwin, M. B.; Zou, S.; Bonnell, J. W.; Angelopoulos, V.

    2015-01-01

    Ultralow-frequency (ULF) waves—in particular, Alfvén waves-transfer energy into the Earth's ionosphere via Joule heating, but it is unclear how much they contribute to global and local heating rates relative to other energy sources. In this study we use Time History of Events and Macroscale Interactions during Substorms satellite data to investigate the spatial, frequency, and geomagnetic activity dependence of the ULF wave Poynting vector (electromagnetic energy flux) mapped to the ionosphere. We use these measurements to estimate Joule heating rates, covering latitudes at or below the nominal auroral oval and below the open/closed field line boundary. We find ULF wave Joule heating rates (integrated over 3-30 mHz frequency band) typically range from 0.001 to 1 mW/m2. We compare these rates to empirical models of Joule heating associated with large-scale, static (on ULF wave timescales) current systems, finding that ULF waves nominally contribute little to the global, integrated Joule heating rate. However, there are extreme cases with ULF wave Joule heating rates of ≥10 mW/m2—in these cases, which are more likely to occur when Kp ≥ 3, ULF waves make significant contributions to the global Joule heating rate. We also find ULF waves routinely make significant contributions to local Joule heating rates near the noon and midnight local time sectors, where static current systems nominally contribute less to Joule heating; the most important contributions come from lower frequency (<7 mHz) waves.

  18. Spectroscopy of candidate electromagnetic counterparts to gravitational wave sources

    CERN Document Server

    Steele, Iain A; Piascik, Andrzej S

    2016-01-01

    A programme of worldwide, multi-wavelength electromagnetic follow-up of sources detected by gravitational wave detectors is in place. Following the discovery of GW150914 and GW151226, wide field imaging of their sky localisations identified a number of candidate optical counterparts which were then spectrally classified. The majority of candidates were found to be supernovae at redshift ranges similar to the GW events and were thereby ruled out as a genuine counterpart. Other candidates ruled out include AGN and solar system objects. Given the GW sources were black hole binary mergers, the lack of an identified electromagnetic counterpart is not surprising. However the observations show that is it is possible to organise and execute a campaign that can eliminate the majority of potential counterparts. Finally we note the existence of a "classification gap" with a significant fraction of candidates going unclassified.

  19. Rydberg Wave Packets and Half-Cycle Electromagnetic Pulses

    Science.gov (United States)

    Raman, Chandra S.

    1998-05-01

    This dissertation summarizes an examination of the dynamics of atomic Rydberg wave packets with coherent pulses of THz electromagnetic radiation consisting of less than a single cycle of the electric field. The bulk of the energy is contained in just a half-cycle. Previous work ( R. Jones, D. You, and P. Bucksbaum, ``Ionization of Rydberg atoms by subpicosecond half-cycle electromagnetic pulses,'' Phys. Rev. Lett.), vol. 70, 1993. had shown how these half-cycle pulses can be used to ionize the highly excited states of an atom, and that a classical view of electronic motion in the atom explains the ionization mechanism. To further probe the boundary between classical trajectories and quantum mechanics, in this work I investigate dynamical combinations of Rydberg states, or Rydberg wave packets, and how they ionize under the influence of a half-cycle electromagnetic pulse. With time-domain techniques I am able to extract the dynamics of the wave packet from the ionization rate, and to observe wave packet motion in both the electronic radial ( C. Raman, C. Conover, C. Sukenik, and P. Bucksbaum, ``Ionization of Rydberg wavepackets by sub-picosecond half-cycle electromagnetic pulses,'' Phys. Rev. Lett.), vol. 76, 1996.and angular ( C. Raman, T. Weinacht, and P. Bucksbaum, ``Stark wavepackets viewed with half cycle pulses.'' Phys. Rev. A), vol. 55, No. 6, 1997. coordinates. This is the first time a wavepacket technique has been used to view electron motion everywhere on its trajectory, and not just at the nucleus. This is the principal feature of half-cycle pulse ionization. Semiclassical ideas of ionization in conjunction with quantum descriptions of the wave packet, are capable of reproducing the main trends in the data, and in the absence of a rigorous model I rely on these. Experiments of this nature provide examples of the ongoing effort to use the coherent properties of radiation to control electronic motion in an atom, as well as to probe the boundaries between

  20. Three-dimensional Fréchet sensitivity kernels for electromagnetic wave propagation

    Energy Technology Data Exchange (ETDEWEB)

    Strickland, C. E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Univ. of Washington, Seattle, WA (United States); Johnson, T. C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Odom, R. I. [Univ. of Washington, Seattle, WA (United States)

    2015-08-28

    Electromagnetic imaging methods are useful tools for monitoring subsurface changes in pore-fluid content and the associated changes in electrical permittivity and conductivity. The most common method for georadar tomography uses a high frequency ray-theoretic approximation that is valid when material variations are sufficiently small relative to the wavelength of the propagating wave. Georadar methods, however, often utilize electromagnetic waves that propagate within heterogeneous media at frequencies where ray theory may not be applicable. In this paper we describe the 3-D Fréchet sensitivity kernels for EM wave propagation. Various data functional types are formulated that consider all three components of the electric wavefield and incorporate near-, intermediate-, and far-field contributions. We show that EM waves exhibit substantial variations for different relative source-receiver component orientations. The 3-D sensitivities also illustrate out-of-plane effects that are not captured in 2-D sensitivity kernels and can influence results obtained using 2-D inversion methods to image structures that are in reality 3-D.

  1. Explaining Electromagnetic Plane Waves in a Vacuum at the Introductory Level

    Science.gov (United States)

    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…

  2. Surface waves in three-dimensional electromagnetic composites and their effect on homogenization.

    Science.gov (United States)

    Xiong, Xiaoyan Y Z; Jiang, Li Jun; Markel, Vadim A; Tsukerman, Igor

    2013-05-06

    Reflection and transmission of electromagnetic waves at the boundaries of periodic composites (electromagnetic/optical metamaterials) depends in general on both bulk and surface waves. We investigate the interplay of these two contributions using three-dimensional full-wave numerical simulations and a recently developed non-asymptotic homogenization theory.

  3. Explaining Electromagnetic Plane Waves in a Vacuum at the Introductory Level

    Science.gov (United States)

    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…

  4. Transfer Matrix for Obliquely Incident Electromagnetic Waves Propagating in One Dimension Plasma Photonic Crystals

    Institute of Scientific and Technical Information of China (English)

    GUO Bin

    2009-01-01

    Based on the electromagnetic theory and by using an analytical technique-the transfer matrix method,the obliquely incident electromagnetic waves propagating in one-dimension plasma photonic crystals is studied.The dispersion relations for both the P-polarization waves and S-polarization waves,depending on the plasma density,plasma thickness and period,are discussed.

  5. Benchmark of Different Electromagnetic Codes for the High Frequency Calculation

    Energy Technology Data Exchange (ETDEWEB)

    Kai Tian, Haipeng Wang, Frank Marhauser, Guangfeng Cheng, Chuandong Zhou

    2009-05-01

    In this paper, we present benchmarking results for highclass 3D electromagnetic (EM) codes in designing RF cavities today. These codes include Omega3P [1], VORPAL [2], CST Microwave Studio [3], Ansoft HFSS [4], and ANSYS [5]. Two spherical cavities are selected as the benchmark models. We have compared not only the accuracy of resonant frequencies, but also that of surface EM fields, which are critical for superconducting RF cavities. By removing degenerated modes, we calculate all the resonant modes up to 10 GHz with similar mesh densities, so that the geometry approximation and field interpolation error related to the wavelength can be observed.

  6. Features of the ELF Electromagnetic Wave Propagation in the Homogeneous Ionosphere

    Science.gov (United States)

    Sergeev, Igor

    The quasi-stationary Maxwell equations of the gyrotropic waves have been examined. In con-trast to the approach used in the other papers (Sorokin et al., 2009; Sorokin et al., 2006; Sergeev and Sorokin, 2005) the general form of the electromagnetic equation of the gyrotropic waves has been considered. The dispersion equation analysis shows that attenuation of one of the mode tends to zero in the perpendicular to the magnetic field direction while along this direction the attenuation is finite. Basing on this feature we can suppose that low frequency electromagnetic fluctuations tend to expand along the magnetic field. It forms in the iono-sphere long areas with invariable direction of the electric field and current and weakly variable magnitude of these parameters. To check this conclusion the direct problem of the evolution of an electromagnetic fluctuation has been solved numerically. The results show that spherically symmetric fluctuation expands along the magnetic field lines by 5-30 times while in some cases the widening is fully absent. References Sorokin V.M., Sergeev I.Yu., Pokhotelov O.A. Low latitude gyrotropic waves in a finite thickness ionospheric conducting layer. Journal of Atmospheric and Solar-Terrestrial Physics, V. 71, P. 175-179, 2009. Sorokin V.M., Sergeev I.Yu., and Yaschenko A.K. Electromagnetic field generation by explosion in the ionosphere. Advances in Space Research, V. 38, No. 11, P. 2511-2515, 2006. Sergeev I.Yu. and Sorokin V.M. Mechanism of the LF Narrow-Band Spectrum Electromagnetic Disturbance Formation Observed on the Earth Surface during Spacecraft Launches. Geomag-netism and Aeronomy, Vol. 45, No. 4, P. 520-525, 2005.

  7. Features of electromagnetic waves in a complex plasma due to surface plasmon resonances on macroparticles

    CERN Document Server

    Vladimirov, S V

    2015-01-01

    The dielectric properties of complex plasma containing either metal or dielectric spherical inclusions (macroparticles, dust) are investigated. We focus on surface plasmon resonances on the macroparticle surfaces and their effect on electromagnetic wave propagation. It is demonstrated that the presence of surface plasmon oscillations significantly modifies plasma electromagnetic properties by resonances and cutoffs in the effective permittivity. This leads to related branches of electromagnetic waves and to the wave band gaps. The results are discussed in the context of dusty plasma experiments.

  8. Integral Equation Methods for Electromagnetic and Elastic Waves

    CERN Document Server

    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

  9. Plane-Wave Propagation in Electromagnetic PQ Medium

    CERN Document Server

    Lindell, Ismo V

    2015-01-01

    Two basic classes of electromagnetic media, recently defined and labeled as those of P media and Q media, are generalized to define the class of PQ media. Plane wave propagation in the general PQ medium is studied and the quartic dispersion equation is derived in analytic form applying four-dimensional dyadic formalism. The result is verified by considering various special cases of PQ media for which the dispersion equation is known to decompose to two quadratic equations or be identically satisfied (media with no dispersion equation). As a numerical example, the dispersion surface of a PQ medium with non-decomposable dispersion equation is considered.

  10. Electromagnetic wave scattering on nonspherical particles basic methodology and simulations

    CERN Document Server

    Rother, Tom

    2014-01-01

    This book gives a detailed overview of the theory of electromagnetic wave scattering on single, homogeneous, but nonspherical particles. Beside the systematically developed Green’s function formalism of the first edition this second and enlarged edition contains additional material regarding group theoretical considerations for nonspherical particles with boundary symmetries, an iterative T-matrix scheme for approximate solutions, and two additional but basic applications. Moreover, to demonstrate the advantages of the group theoretical approach and the iterative solution technique, the restriction to axisymmetric scatterers of the first edition was abandoned.

  11. Spectrum of classes of point emitters of electromagnetic wave fields.

    Science.gov (United States)

    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.

  12. Electromagnetic form factors of the Δ with D-waves

    Energy Technology Data Exchange (ETDEWEB)

    Ramalho, Gilberto T.F. [CFTP, Institute Superior Tecnico, Lisbon (Portugal); Pena, Maria Teresa [CFTP, Institute Superior Tecnico, Lisbon (Portugal); Gross, Franz L. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

    2010-06-01

    The electromagnetic form factors of the Δ baryon are evaluated within the framework of a covariant spectator quark model, where S and D-states are included in the Δ wave function. We predict all the four Δ multipole form factors: the electric charge GE0, the magnetic dipole GM1, the electric quadrupole GE2 and the magnetic octupole GM3. We compare our predictions with other theoretical calculations. Our results are compatible with the available experimental data and recent lattice QCD data.

  13. Attractors and chaos of electron dynamics in electromagnetic standing waves

    Energy Technology Data Exchange (ETDEWEB)

    Esirkepov, Timur Zh. [QuBS, Japan Atomic Energy Agency, Kizugawa, Kyoto 619-0215 (Japan); Bulanov, Stepan S. [University of California, Berkeley, CA 94720 (United States); Koga, James K.; Kando, Masaki; Kondo, Kiminori [QuBS, Japan Atomic Energy Agency, Kizugawa, Kyoto 619-0215 (Japan); Rosanov, Nikolay N. [Vavilov State Optical Institute, Saint-Petersburg 199034 (Russian Federation); Korn, Georg [ELI Beamline Facility, Institute of Physics, Czech Academy of Sciences, Prague 18221 (Czech Republic); Bulanov, Sergei V., E-mail: bulanov.sergei@jaea.go.jp [QuBS, Japan Atomic Energy Agency, Kizugawa, Kyoto 619-0215 (Japan)

    2015-09-25

    In an electromagnetic standing wave formed by two super-intense colliding laser pulses, radiation reaction totally modifies the electron motion. The quantum corrections to the electron motion and the radiation reaction force can be independently small or large, depending on the laser intensity and wavelength, thus dividing the parameter space into 4 domains. The electron motion evolves to limit cycles and strange attractors when radiation reaction dominates. This creates a new framework for high energy physics experiments on the interaction of energetic charged particle beams and colliding super-intense laser pulses.

  14. Electromagnetic form factors of the Delta with D-waves

    CERN Document Server

    Ramalho, G; Gross, Franz

    2010-01-01

    The electromagnetic form factors of the Delta baryon are evaluated within the framework of a covariant spectator quark model, where S and D-states are included in the $\\Delta$ wave function. We predict all the four Delta multipole form factors: the electric charge GE0, the magnetic dipole GM1, the electric quadrupole GE2 and the magnetic octupole GM3. We compare our predictions with other theoretical calculations. Our results are compatible with the available experimental data and recent lattice QCD data.

  15. Electromagnetic Wave Scattering on Nonspherical Particles Basic Methodology and Simulations

    CERN Document Server

    Rother, Tom

    2009-01-01

    This book gives a detailed overview of the theory of electromagnetic wave scattering on single, homogeneous, but nonspherical particles. A related Green’s function formalism is systematically developed which provides a powerful mathematical basis not only for the development of numerical approaches but also to discuss those general aspects like symmetry, unitarity, and the validity of Rayleigh’s hypothesis. Example simulations are performed in order to demonstrate the usefulness of the developed formalism as well as to introduce the simulation software which is provided on a CD-ROM with the book.

  16. 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.

  17. Motion of a charge in a superstrong electromagnetic standing wave

    Science.gov (United States)

    Esirkepov, Timur Z.; Bulanov, Stepan S.; Koga, James K.; Kando, Masaki; Kondo, Kiminori; Rosanov, Nikolay N.; Korn, Georg; Bulanov, Sergei V.

    2015-05-01

    Radiation reaction radically influences the electron motion in an electromagnetic standing wave formed by two super-intense colliding laser pulses. Depending on the laser intensity and wavelength, the quantum corrections to the electron motion and the radiation reaction force can be independently small or large, thus dividing the parameter space into 4 regions. When radiation reaction dominates, the electron motion evolves to limit cycles and strange attractors. This creates a new framework for high energy physics experiments on the interaction of energetic charged particle beams and colliding super-intense laser pulses.

  18. Attractors and chaos of electron dynamics in electromagnetic standing waves

    Science.gov (United States)

    Esirkepov, Timur Zh.; Bulanov, Stepan S.; Koga, James K.; Kando, Masaki; Kondo, Kiminori; Rosanov, Nikolay N.; Korn, Georg; Bulanov, Sergei V.

    2015-09-01

    In an electromagnetic standing wave formed by two super-intense colliding laser pulses, radiation reaction totally modifies the electron motion. The quantum corrections to the electron motion and the radiation reaction force can be independently small or large, depending on the laser intensity and wavelength, thus dividing the parameter space into 4 domains. The electron motion evolves to limit cycles and strange attractors when radiation reaction dominates. This creates a new framework for high energy physics experiments on the interaction of energetic charged particle beams and colliding super-intense laser pulses.

  19. Electromagnetic Wave Absorption Property of Graphene with FeO4 Nanoparticles.

    Science.gov (United States)

    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.

  20. Collision of arbitrary strong gravitational and electromagnetic waves in the expanding universe

    CERN Document Server

    Alekseev, G A

    2015-01-01

    A completely analytical model of the process of collision and nonlinear interaction of gravitational and electromagnetic soliton wave pulses and strong electromagnetic travelling waves of arbitrary profiles propagating in the expanding universe (symmetric Kasner space-time) is presented. In contrast to intuitive expectations that rather strong travelling waves can destroy the soliton, it occurs that the soliton survives during its interaction with electromagnetic wave of arbitrary amplitude and profile, but its parameters begin to evolve under the influence of this interaction. If a travelling electromagnetic wave possesses a finite duration, the soliton parameters after interaction take constant values again, but these values in general are different from those before the interaction. Based on exact solutions of Einstein - Maxwell equations, our model demonstrates a series of nonlinear phenomena, such as (a) creation of gravitational waves in the collision of two electromagnetic waves, (b) creation of electr...

  1. Development of an electromagnetic acoustic transducer (EMAT) for the noncontact excitation of guided ultrasonic waves

    Science.gov (United States)

    Fromme, P.

    2015-03-01

    Fatigue damage can develop in aerospace structures at locations of stress concentration, such as fasteners. For the safe operation of the aircraft fatigue cracks need to be detected before reaching a critical length. Guided ultrasonic waves offer an efficient method for the detection and characterization of such defects in large aerospace structures. Noncontact excitation of guided waves was achieved using electromagnetic acoustic transducers (EMAT). The transducer development for the specific excitation of the A0 Lamb wave mode is explained. The radial and angular dependency of the excited guided wave pulses at different frequencies were measured using a noncontact laser interferometer. Based on the induced eddy currents in the plate a theoretical model was developed and reasonably good agreement with the measured transducer performance was achieved. The developed transducers were employed for defect detection in aluminum components using fully noncontact guided wave measurements. Excitation of the A0 Lamb wave mode was achieved using the developed EMAT transducer and the guided wave propagation and scattering was measured using a noncontact laser interferometer. These results provide the basis for the defect characterization in aerospace structures using noncontact guided wave sensors.

  2. Effect of Electromagnetic Frequency on Microstructures of Continuous Casting Aluminum Alloys

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The relationship between electromagnetic frequency and microstructures of continuous casting aluminum alloyswas studied. 7075 aluminum alloy ingot of 100 mm in diameter was produced by electromagnetic continuouscasting process, the microstructures of as-cast ingot was examined by scanning electron microscopy (SEM) equippedwith energy dispersive spectrometer (EDS). The results showed that electromagnetic frequency greatly influencedsegregation and microstructures of as-cast ingot, and product quality can be guaranteed by the application of aproper frequency. Electromagnetic frequency plays a significant role in solute redistribution; Iow frequency is moreefficient for promoting solution of alloying elements.

  3. A Behavior Level Analytical Method of Electromagnetic Susceptibility for Radio Frequency Receiver

    Institute of Scientific and Technical Information of China (English)

    YAN Zhaowen; YU Xiaofeng; XIE Shuguo; LIU Yan

    2011-01-01

    Based on simplified Volterra model, a behavior-level simulation analysis approach of electromagnetic susceptibility (EMS) for radio frequency (RF) receiver is presented in this article. Third order simplified Volterra model is adopted to analyze receiver EMS. A general criterion for EMS is proposed according to EMS response characteristics in frequency domain, and then the simulation flow charts for calculating susceptibility thresholds are given. This approach is superior to the previous EMS analysis method on receiver, which mainly relies on experiments but lack simulation analysis. Take the dual frequency GPS receiver and zero IF receiver interfered by continue wave as examples for in-band and out-of-band susceptibility threshold calculation. Simulation results show that the proposed method is not only valid and effective, but also reduces the internal storage and simulation time, which is suitable to RF receiver EMS analysis and practical in engineering and technology field.

  4. Nearly non-scattering electromagnetic wave set and its application

    Science.gov (United States)

    Liu, Hongyu; Wang, Yuliang; Zhong, Shuhui

    2017-04-01

    For any inhomogeneous compactly supported electromagnetic (EM) medium, it is shown that there exists an infinite set of linearly independent EM waves which generate nearly vanishing scattered wave fields. If the inhomogeneous medium is coated with a layer of properly chosen conducting medium, then the wave set is generated from the Maxwell-Herglotz approximation to the interior perfectly electric conducting or perfectly magnetic conducting eigenfunctions and depends only on the shape of the inhomogeneous medium. If no such a conducting coating is used, then the wave set is generated from the Maxwell-Herglotz approximation to the generalised interior transmission eigenfunctions and depends on both the content and shape of the inhomogeneous medium. We characterise the nearly non-scattering wave sets in both cases with sharp estimates. The results can be used to give a conceptual design of a novel shadowless lamp. The crucial ingredient is to properly choose the source of the lamp so that nearly no shadow will be produced by surgeons operating under the lamp.

  5. Wave fields in real media wave propagation in anisotropic, anelastic, porous and electromagnetic media

    CERN Document Server

    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 ...

  6. Electromagnetic waves in complex systems selected theoretical and applied problems

    CERN Document Server

    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. .

  7. Ultra-fast multiple tunnelling of electromagnetic X-waves

    Energy Technology Data Exchange (ETDEWEB)

    Shaarawi, Amr M. [Physics Department, American University in Cairo, Cairo (Egypt); Besieris, Ioannis M. [Bradley Department of Electrical and Computer Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA (United States)

    2000-12-01

    A study is provided of the transmission of a three-dimensional electromagnetic X-wave undergoing frustrated total internal reflection on the upper surface of a multi-layered structure. The stratified structure consists of successive layers alternately allowing the transmission of evanescent and free-propagation components. It is shown that the peak of an X-wave is transmitted through these successive layers at an ultra-fast speed. Under certain conditions, the total traversal time through all successive evanescent and free-propagation sections appears to be less than zero. The peak of the transmitted pulse emerges from the stack before the incident peak reaches the front surface of the stratified structure. Conditions for the materialization of this ultra-fast multiple tunnelling of pulses are pointed out and their consequences and limitations are discussed. (author)

  8. Energy transfer between energetic ring current H(+) and O(+) by electromagnetic ion cyclotron waves

    Science.gov (United States)

    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.

  9. Nonlinear interaction of intense electromagnetic waves with a magnetoactive electron-positron-ion plasma

    Energy Technology Data Exchange (ETDEWEB)

    Khorashadizadeh, S. M.; Rastbood, E.; Zeinaddini Meymand, H. [Physics Department, University of Birjand, Birjand (Iran, Islamic Republic of); Niknam, A. R. [Laser and Plasma Research Institute, Shahid Beheshti University, G.C., Tehran (Iran, Islamic Republic of)

    2013-08-15

    The nonlinear coupling between circularly polarized electromagnetic (CPEM) waves and acoustic-like waves in a magnetoactive electron-positron-ion (e-p-i) plasma is studied, taking into account the relativistic motion of electrons and positrons. The possibility of modulational instability and its growth rate as well as the envelope soliton formation and its characteristics in such plasmas are investigated. It is found that the growth rate of modulation instability increases in the case that ω{sub c}/ω<1 (ω{sub c} and ω are the electron gyrofrequency and the CPEM wave frequency, respectively) and decreases in the case that ω{sub c}/ω>1. It is also shown that in a magnetoactive e-p-i plasma, the width of bright soliton increases/decreases in case of (ω{sub c}/ω)<1/(ω{sub c}/ω)>1 by increasing the magnetic field strength.

  10. The operation of stochastic heating mechanisms in an electromagnetic standing wave configuration

    Energy Technology Data Exchange (ETDEWEB)

    Gell, Y.; Nakach, R.

    1991-10-01

    The possibility of the operation of stochastic heating mechanisms of charged particles in a configuration consisting of a left-handed circularly polarized standing electromagnetic wave and a uniform magnetic field, has been studied numerically and theoretically. It is found that such a configuration induces stochasticity, the threshold of which is dependent on two independent parameters, determined by the frequency and the amplitude of the wave and the strength of the magnetic field. From the theoretical analysis, it emerges that the origin of onset of large scale stochasticity is the destabilization of fixed points associated with an equation describing the motion of the particles in an electrostatic-type potential having standing wave characteristics. The comparison of the theoretical predictions with the numerical results is found to be quite satisfactory. Possible applications to realistic plasmas have been discussed.

  11. Continuous-wave four-wave mixing with linear growth based on electromagnetically dual induced transparency

    Institute of Scientific and Technical Information of China (English)

    Jiahua Li(李家华); Wenxing Yang(杨文星); Jucun Peng(彭菊村)

    2004-01-01

    Using Schrodinger-Maxwell formalism, we propose and analyze a continuous-wave four-wave mixing (FWM) scheme for the generation of coherent light in a six-level atomic system based on electromagnetically dual induced transparency. We derive the corresponding explicit analytical expressions for the generated mixing field. We find that the scheme greatly enhances FWM production efficiency and is also capable of inhibiting and delaying the onset of the detrimental three-photon destructive interference by choosing the proper decay rate in the second electromagnetically induced transparency (EIT) process.In addition, such an optical process also provides possibilities for producing short-wave-length coherent radiation at low pump intensities.

  12. On the frequency shift of gravitational waves

    CERN Document Server

    De Sousa, C M G

    2002-01-01

    Considering plane gravitational waves propagating through flat spacetime, it is shown that curvatures experienced both in the starting point and during their arrival at the earth can cause a considerable shift in the frequencies as measured by earth and space-based detectors.

  13. 高频引力波在电磁环形腔焦点区域的时空扰动效应%Perturbative Effect of Spacetime Produced by High-Frequency Gravitational Waves in Focal Region of Electromagnetic Toroidal Cavity

    Institute of Scientific and Technical Information of China (English)

    丁亮; 邓丽城; 陈珊珊

    2011-01-01

    Christoffel connection, ricci tensor, curvature scalar and energy density of the standing gravitational wave produced by strong electromagnetic normal mode of the toroidal cavity in its focal region is calculated in this study, using the cylindrical coordinate system, under the condition of weak field. The energy density of the standing gravitational wave is found to be positive definite in the focal region of the cavity. The relationship between energy density of the gravitational wave and curvature scalar is discussed. Both the microwave cavity of strong field with high quality factor Q and the nuclear fusion device Tokamak are characterized by axial symmetry and can be used as potential sources of high-frequency gravitational waves. The conclusions as shown above may have a prospective significance for producing and detecting high-frequency gravitational waves.%基于弱场条件,计算了在柱坐标下由电磁环形腔中强电磁简正模在其焦点区域产生的引力驻波的第二类克氏联络、里奇张量、曲率标量及其能量密度.研究发现,在焦点区域的引力驻波的能量密度是正定的.此外,讨论了该引力驻波的能量密度和时空的曲率标量的关系.高Q值强场环形微波腔以及受控核聚变的Tokamak装置均具有轴对称的特点,并可作为可能的潜在高频引力波源.

  14. Responses of Waveform-Selective Absorbing Metasurfaces to Oblique Waves at the Same Frequency.

    Science.gov (United States)

    Wakatsuchi, Hiroki; Gao, Fei; Yagitani, Satoshi; Sievenpiper, Daniel F

    2016-08-12

    Conventional materials vary their electromagnetic properties in response to the frequency of an incoming wave, but these responses generally remain unchanged at the same frequency unless nonlinearity is involved. Waveform-selective metasurfaces, recently developed by integrating several circuit elements with planar subwavelength periodic structures, allowed us to distinguish different waves even at the same frequency depending on how long the waves continued, namely, on their pulse widths. These materials were thus expected to give us an additional degree of freedom to control electromagnetic waves. However, all the past studies were demonstrated with waves at a normal angle only, although in reality electromagnetic waves scatter from various structures or boundaries and therefore illuminate the metasurfaces at oblique angles. Here we study angular dependences of waveform-selective metasurfaces both numerically and experimentally. We demonstrate that, if designed properly, capacitor-based waveform-selective metasurfaces more effectively absorb short pulses than continuous waves (CWs) for a wide range of the incident angle, while inductor-based metasurfaces absorb CWs more strongly. Our study is expected to be usefully exploited for applying the concept of waveform selectivity to a wide range of existing microwave devices to expand their functionalities or performances in response to pulse width as a new capability.

  15. Frequency-Domain Green's Functions for Radar Waves in Heterogeneous 2.5D Media

    Science.gov (United States)

    Green’s functions for radar waves propagating in heterogeneous media may be calculated in the frequency domain using a hybrid of two numerical methods. The model is defined in the Cartesian coordinate system, and its electromagnetic properties may vary in the x and z directions, ...

  16. Electromagnetic wave propagation of wireless capsule endoscopy in human body

    Institute of Scientific and Technical Information of China (English)

    LIM; Eng-Gee; 王炤; 陈瑾慧; TILLO; Tammam; MAN; Ka-lok

    2013-01-01

    Wireless capsule endoscopy(WCE) is a promising technique which has overcome some limitations of traditional diagnosing tools, such as the comfortlessness of the cables and the inability of examining small intestine section. However, this technique is still far from mature and asks for the feasible improvements. For example, the relatively low transmission data rate and the absence of the real-time localization information of the capsule are all important issues. The studies of them rely on the understanding of the electromagnetic wave propagation in human body. Investigation of performance of WCE communication system was carried out by studying electromagnetic(EM) wave propagation of the wireless capsule endoscopy transmission channel. Starting with a pair of antennas working in a human body mimic environment, the signal transmissions and attenuations were examined. The relationship between the signal attenuation and the capsule(transmitter) position, and direction was also evaluated. These results provide important information for real-time localization of the capsule. Moreover, the pair of antennas and the human body were treated as a transmission channel, on which the binary amplitude shift keying(BASK) modulation scheme was used. The relationship between the modulation scheme, data rate and bit error rate was also determined in the case of BASK. With the obtained studies, it make possible to provide valuable information for further studies on the selection of the modulation scheme and the real-time localization of the capsules.

  17. Shaping electromagnetic waves using software-automatically-designed metasurfaces.

    Science.gov (United States)

    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.

  18. Laser frequency locking based on Rydberg electromagnetically induced transparency

    Science.gov (United States)

    Yuechun, Jiao; Jingkui, Li; Limei, Wang; Hao, Zhang; Linjie, Zhang; Jianming, Zhao; Suotang, Jia

    2016-05-01

    We present a laser frequency locking to Rydberg transition with electromagnetically induced transparency (EIT) spectra in a room-temperature cesium vapor cell. Cesium levels 6S1/2, 6P3/2, and the nD5/2 state, compose a cascade three-level system, where a coupling laser drives Rydberg transition, and probe laser detects the EIT signal. The error signal, obtained by demodulating the EIT signal, is used to lock the coupling laser frequency to Rydberg transition. The laser frequency fluctuation, ˜0.7 MHz, is obtained after locking on, with the minimum Allan variance to be 8.9 × 10-11. This kind of locking method can be used to stabilize the laser frequency to the excited transition. Project supported by the National Basic Research Program of China (Grant No. 2012CB921603), the National Natural Science Foundation of China (Grants Nos. 11274209, 61475090, 61378039, and 61378013), and the Research Project Supported by Shanxi Scholarship Council of China (Grant No. 2014-009).

  19. Public Protection from Electromagnetic Fields of Industry Frequency

    Directory of Open Access Journals (Sweden)

    Kazimieras Vytautas Maceika

    2006-01-01

    Full Text Available Lithuania introduced normative of public protection from 50 Hz frequency electric field. It proposed permissible intensity of this field – 0,5 kV/m inside buildings and 1 kV/m in their territory. Separate normative is prepared for industry frequency electric and magnetic fields in work places. Permitted values of fields depend on exposure duration, but cannot exceed 25 kV/m and 5,1 kA/m. Russian, Swedish and American scientists declare that long time exposure of 50 Hz magnetic field with intensity more than 0,2-0,3 µT is dangerous for carcinogenic risk. International Agency for research on Cancer (IARC initiated a program to evaluate the carcinogenic risk of low frequency electromagnetic fields to humans and till 2002 year collected a lot of information for different countries with quantitative analysis of epidemic data. Standardized incidents ratio (SIR was proposed for evaluation of leukaemia in humans and especially children. Exposure of children in magneticfields > 0,4 µT showed a twofold SIR increasing. Data concerning the subject of an evaluation did not disclose inadequate evidence in humans and experimental animals for the carcinogenicity of magnetic fields of industry frequency, but they are classified as “possibly carcinogenic to humans”.

  20. Global Evolutionary Algorithms in the Design of Electromagnetic Band Gap Structures with Suppressed Surface Waves Propagation

    Directory of Open Access Journals (Sweden)

    P. Kovacs

    2010-04-01

    Full Text Available The paper is focused on the automated design and optimization of electromagnetic band gap structures suppressing the propagation of surface waves. For the optimization, we use different global evolutionary algorithms like the genetic algorithm with the single-point crossover (GAs and the multi-point (GAm one, the differential evolution (DE and particle swarm optimization (PSO. The algorithms are mutually compared in terms of convergence velocity and accuracy. The developed technique is universal (applicable for any unit cell geometry. The method is based on the dispersion diagram calculation in CST Microwave Studio (CST MWS and optimization in Matlab. A design example of a mushroom structure with simultaneous electromagnetic band gap properties (EBG and the artificial magnetic conductor ones (AMC in the required frequency band is presented.

  1. Penetration and screening of perpendicularly launched electromagnetic waves through bounded supercritical plasma confined in multicusp magnetic field

    Science.gov (United States)

    Dey, Indranuj; Bhattacharjee, Sudeep

    2011-02-01

    The question of electromagnetic wave penetration and screening by a bounded supercritical (ωp>ω with ωp and ω being the electron-plasma and wave frequencies, respectively) plasma confined in a minimum B multicusp field, for waves launched in the k ⊥Bo mode, is addressed through experiments and numerical simulations. The scale length of radial plasma nonuniformity (|ne/(∂ne/∂r)|) and magnetostatic field (Bo) inhomogeneity (|Bo/(∂Bo/∂r)|) are much smaller than the free space (λo) and guided wavelengths (λg). Contrary to predictions of plane wave dispersion theory and the Clemow-Mullaly-Allis (CMA) diagram, for a bounded plasma a finite propagation occurs through the central plasma regions where αp2=ωp2/ω2≥1 and βc2=ωce2/ω2≪1(˜10-4), with ωce being the electron cyclotron frequency. Wave screening, as predicted by the plane wave model, does not remain valid due to phase mixing and superposition of reflected waves from the conducting boundary, leading to the formation of electromagnetic standing wave modes. The waves are found to satisfy a modified upper hybrid resonance (UHR) relation in the minimum B field and are damped at the local electron cyclotron resonance (ECR) location.

  2. Application of electromagnetic-wave-ionospheric interactions to global warming in the arctic region

    Science.gov (United States)

    Wong, A. Y.

    An approach to expel pollutants which can contribute to global warming from the upper atmosphere by the use of HF electromagnetic waves has been proposed [1]. Laboratory plasma experiments have shown that significant gyro-resonance acceleration of minority ion species in a plasma is possible. The separation of ions differing in mass by one unit has been achieved. This method is applicable to the selective acceleration of ions perpendicular to the geomagnetic field in the ionosphere and involves the modulation of the auroral electrojet current to excite ion cyclotron waves. On account of the divergent geomagnetic field in the polar atmosphere the accelerated perpendicular ion velocity is converted into an upward motion along open magnetic field lines. The ions thus removed will not return to the upper atmosphere. Negatively charged particles move upward by the fair-weather electric field and by atmospheric convection. When ions reach above 120˜ km altitude where the ion gyro-frequency is comparable to or greater than the ion-neutral collision frequency, they can be accelerated by electromagnetic fields through the gyro-resonance interaction. By modulating the auroral electrojet in the gyro-frequency range for important minority ion species (˜ 15--30 Hz for CO2-, and Cl-) electromagnetic ion cyclotron waves can be excited, which propagate nearly along the geomagnetic field lines. Experimental evidence for this effect has been obtained with the HIPAS facility [Wong et al., 1997]. When exciting ELF waves over a range of ion gyro-frequencies of dominant ion species, dips were observed in magnetometer data at ion gyro-frequencies of various species, which suggests that the ELF wave energy was absorbed by ions. Similar ion acceleration and expelling phenomenon over the polar regions occurs naturally in so called ion conics as observed by high latitude satellites. Field aligned currents might provide the free energy needed to make this process practical. Field

  3. Influence of electromagnetism field on the flame transmission and shock wave in gas explosion

    Energy Technology Data Exchange (ETDEWEB)

    Li Jing [Anhui University of Technology, Maanshan (China). College of Metallurgy and Resources

    2008-01-15

    The influence of electromagnetic field on flame transmission and explosion wave overpressure in gas explosions was investigated. The research results show that the velocity of flame propagation and the explosion wave overpressure in an electromagnetic field is much higher than that in plain tube, and the stronger the electromagnetic field, the greater the influence. Based on experimental results, the influence of electromagnetic field on gas explosion propagation was analyzed and a reasonable explanation was put forward. The influence of electromagnetic field is not equal to the sum of the electric field and the magnetic field. 7 refs., 4 figs., 2 tabs.

  4. Three-Dimensional Electromagnetic High Frequency Axisymmetric Cavity Scars.

    Energy Technology Data Exchange (ETDEWEB)

    Warne, Larry Kevin; Jorgenson, Roy Eberhardt

    2014-10-01

    This report examines the localization of high frequency electromagnetic fi elds in three-dimensional axisymmetric cavities along periodic paths between opposing sides of the cavity. The cases where these orbits lead to unstable localized modes are known as scars. This report treats both the case where the opposing sides, or mirrors, are convex, where there are no interior foci, and the case where they are concave, leading to interior foci. The scalar problem is treated fi rst but the approximations required to treat the vector fi eld components are also examined. Particular att ention is focused on the normalization through the electromagnetic energy theorem. Both projections of the fi eld along the scarred orbit as well as point statistics are examined. Statistical comparisons are m ade with a numerical calculation of the scars run with an axisymmetric simulation. This axisymmetric cas eformstheoppositeextreme(wherethetwomirror radii at each end of the ray orbit are equal) from the two -dimensional solution examined previously (where one mirror radius is vastly di ff erent from the other). The enhancement of the fi eldontheorbitaxiscanbe larger here than in the two-dimensional case. Intentionally Left Blank

  5. Radio frequency electromagnetic fields: cancer, mutagenesis, and genotoxicity.

    Science.gov (United States)

    Heynick, Louis N; Johnston, Sheila A; Mason, Patrick A

    2003-01-01

    We present critiques of epidemiologic studies and experimental investigations, published mostly in peer-reviewed journals, on cancer and related effects from exposure to nonionizing electromagnetic fields in the nominal frequency range of 3 kHz to 300 GHz of interest to Subcommittee 4 (SC4) of the International Committee on Electromagnetic Safety (ICES). The major topics discussed are presented under the headings Epidemiologic and Other Findings on Human Exposure, Mammals Exposed In Vivo, Mammalian Live Tissues and Cell Preparations Exposed In Vitro, and Mutagenesis and Genotoxicity in Microorganisms and Fruit Flies. Under each major topic, we present minireviews of papers on various specific endpoints investigated. The section on Epidemiologic and Other Findings on Human Exposure is divided into two subsections, the first on possible carcinogenic effects of exposure from emitters not in physical contact with the populations studied, for example, transmitting antennas and other devices. Discussed in the second subsection are studies of postulated carcinogenic effects from use of mobile phones, with prominence given to brain tumors from use of cellular and cordless telephones in direct physical contact with an ear of each subject. In both subsections, some investigations yielded positive findings, others had negative findings, including papers directed toward experimentally verifying positive findings, and both were reported in a few instances. Further research on various important aspects may resolve such differences. Overall, however, the preponderance of published epidemiologic and experimental findings do not support the supposition that in vivo or in vitro exposures to such fields are carcinogenic.

  6. Modal Ring Method for the Scattering of Electromagnetic Waves

    Science.gov (United States)

    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.

  7. Assessment of occupational exposure to radio frequency electromagnetic fields

    Directory of Open Access Journals (Sweden)

    Halina Aniołczyk

    2015-06-01

    Full Text Available Background: European Union Directive 2013/35/UE provides for the implementation of EU regulations into national legislation. Our aim is to assess actual health hazards from radiofrequency electromagnetic field (RF EMF (range: 100 kHz – 300 GHz and indicate workplaces with the highest risk to employee health. Material and Methods: Data from measurements of RF EMF performed by the Laboratory of Electromagnetic Hazards in Nofer Institute of Occupational Medicine (Łódź, Poland were analyzed. The analysis covered the results of electric field intensity (E for over 450 selected items. The ranges of protection zones and the extent to which maximum admissible intensity (MAI values were also analyzed. The determinations and measurements of EMF in the work environment met the requirements of Polish Standard, while Polish regulations on the MAI values were used as the criterion for the assessment of the exposure. Results: The highest values of E field intensity at workplaces were measured for: electrosurgery, to 400 V/m, and short-wave diathermy units, to 220 V/m, dielectric welders to 240 V/m, within the FM radio antenna systems, to 180 V/m. The widest protection zones were noted for prototype research instruments, short-wave diathermy units, and dielectric welders. The most excessive (up to 12-fold MAI values were recorded for dielectric welders, short-wave diathermy units (up to 11-fold and microwave diathermy units (up to 8-fold. Conclusions: Our results have confirmed the high RF EMF values for physiotherapists, operators of dielectric welders, and mast maintenance workers in radio communication facilities (especially radio and TV broadcasting stations. Med Pr 2015;66(2:199–212

  8. Electromagnetic wave absorbing characteristics of synthetized barium strontium titanate/polyaniline nanocomposites

    Science.gov (United States)

    Mulyani, O.; Hafizah, M. A. E.; Manaf, A.

    2017-07-01

    In this paper, electromagnetic wave absorbing characteristics of electrically conductive composites consisted of polyaniline (PANi) and nanoparticles of barium strontium titanate (BST) is described. The BST nanoparticles were synthesized by the mechanical alloying method and successive particle size reduction steps through high frequency ultrasonic irradiation treatments. Whereas polyaniline was produced by oxidative polymerization processes which allows efficient control of the dielectric properties. Mechanical alloying combined with ultrasonic irradiation treatments has resulted in BST powders with a mean particle size of a few nanometers (less than 100 nm). Such ultra-fine particles of BST were then used to synthesize the BST/PANi nanocomposites with 20:80, 50:50 and 80:20 compositions. The physical properties like particle sizes, dielectric constant, electromagnetic absorption characteristics are investigated by X-Ray Diffractometer, Fourier Transform Infrared, and Vector Network Analyzer. It was found that BST/polyaniline nanocomposite can enhance main properties of the electromagnetic absorber. The high dielectric constant of BST and conductivity of polyaniline support nanocomposite BST/polyaniline as electromagnetic absorber materials.

  9. Parametric frequency fusion by inverse four-wave mixing

    CERN Document Server

    Sylvestre, Thibaut

    2015-01-01

    This work reports the experimental observation of a new type of four-wave mixing in which frequency-degenerate weak signal and idler waves are generated by mixing two pump waves of different frequencies in a normally dispersive birefringent optical fiber. This parametric frequency fusion is what we believed the first experimental evidence of inverse four-wave mixing.

  10. Interaction of Oblique Incident Electromagnetic Wave with Relativistic Ionization Front

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Interactions of oblique incident probe wave with oncoming ionization fronts have been investigated using moving boundary conditions. Field conversion coefficients of reflection,transmission and magnetic modes produced in the interactions are derived. Phase matching conditions at the front and frequency up-shifting formulas for the three modes are also presented.

  11. Behavior of radon progeny in low frequency electromagnetic fields

    CERN Document Server

    Oda, K; Yamamoto, T

    1999-01-01

    Whether the electro-magnetic (EM) fields are carcinogenic or not still remains to be discussed from scientific point of view. Recently a possibility was pointed out that increased deposition of radon progeny in the EM-fields should enhance exposure dose to internal body. We investigated the behavior of charged sup 2 sup 2 sup 2 Rn progeny and aerosols containing them by measuring the pattern and the magnitude of the deposition rate of decay products on both CR-39 track detectors and imaging plates under various conditions. We concluded that the attachment to wire cables should be increased mainly by electric component of low frequency EM-fields and possibly by electric field induced by strong changing magnetic ones.

  12. Experimental Investigation on Electromagnetic Attenuation by Low Pressure Radio-Frequency Plasma for Cavity Structure

    Science.gov (United States)

    He, Xiang; Zhang, Yachun; Chen, Jianping; Chen, Yudong; Zeng, Xiaojun; Yao, Hong; Tang, Chunmei

    2016-01-01

    This paper reports on an experiment designed to test electromagnetic (EM) attenuation by radio-frequency (RF) plasma for cavity structures. A plasma reactor, in the shape of a hollow cylinder, filled with argon gas at low pressure, driven by a RF power source, was produced by wave-transmitting material. The detailed attenuations of EM waves were investigated under different conditions: the incident frequency is 1-4 GHz, the RF power supply is 13.56 MHz and 1.6-3 kW, and the argon pressure is 75-200 Pa. The experimental results indicate that 5-15 dB return loss can be obtained. From a first estimation, the electron density in the experiment is approximately (1.5-2.2) × 1016 m-3 and the collision frequency is about 11-30 GHz. The return loss of EM waves was calculated using a finite-difference time-domain (FDTD) method and it was found that it has a similar development with measurement. It can be confirmed that RF plasma is useful in the stealth of cavity structures such as jet-engine inlet. supported by National Natural Science Foundation of China (No. 51107033) and the Fundamental Research Funds for the Central Universities of China (No. 2013B33614)

  13. Low-frequency electromagnetic technique for nondestructive evaluation

    Science.gov (United States)

    Dalichaouch, Yacine; Singsaas, Alan L.; Putris, Firas; Perry, Alexander R.; Czipott, Peter V.

    2000-05-01

    We have developed a low frequency electromagnetic technique using sensitive room temperature magnetoresistive (MR) sensors for a variety of nondestructive evaluation (NDE) applications. These applications include the NDE of medical implants and aircraft structures, the detection of cracks and corrosion in metals, the detection of ferromagnetic foreign objects in the eye and the brain, and the noninvasive determination of iron content in the liver. Our technique consists of applying a low frequency ac magnetic field to the sample and detecting the sample response. The low excitation frequency enables us to probe deep into metal structures; the sensitivity of the MR sensor allows us to detect weak responses from the sample without applying too large an excitation field, particularly in the case of human tissue. The MR sensors are small and relatively inexpensive compared to other sensitive magnetic field sensors such as fluxgates and superconducting quantum interference devices or SQUIDs; hence the resulting NDE instrument will be compact and cost-efficient, enabling its commercialization for practical applications. In this paper, we focus primarily on NDE of orthopedic implants.

  14. Examination of Bursty Electromagnetic Waves Observed During Intervals of Turbulent Magnetosheath Reconnection

    Science.gov (United States)

    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.

  15. Theoretical study of electromagnetic electron cyclotron waves in the presence of AC field in Uranian magnetosphere

    Science.gov (United States)

    Pandey, R. S.; Kaur, Rajbir

    2015-10-01

    Electromagnetic electron cyclotron (EMEC) waves with temperature anisotropy in the magnetosphere of Uranus have been studied in present work. EMEC waves are investigated using method of characteristic solution by kinetic approach, in presence of AC field. In 1986, Voyager 2 encounter with Uranus revealed that magnetosphere of Uranus exhibit non-Maxwellian high-energy tail distribution. So, the dispersion relation, real frequency and growth rate are evaluated using Lorentzian Kappa distribution function. Effect of temperature anisotropy, AC frequency and number density of particles is found. The study is also extended to oblique propagation of EMEC waves in presence and absence of AC field. Through comprehensive mathematical analysis it is found that when EMEC wave propagates parallel to intrinsic magnetic field of Uranus, its growth is more enhanced than in case of oblique propagation. Results are also discussed in context to magnetosphere of Earth and also gives theoretical explanation to existence of high energetic particles observed by Voyager 2 in the magnetosphere of Uranus. The results can present a further insight into the nature of electron-cyclotron instability condition for the whistler mode waves in the outer radiation belts of Uranus or other space plasmas.

  16. CORTIZOL LEVEL AND ADRENAL GLAND MORPHOLOGY UNDER INFLUENCE OF LOW-INTENSITY ELECTRO-MAGNETIC WAVES AND UNDER STRESS

    Directory of Open Access Journals (Sweden)

    L.I. Naumova

    2008-03-01

    Full Text Available Low-intensify electro-magnetic waves (EMW influence were studied at experiment. Certain EMI frequency regimes (they are transparent for the water and water-binding substances, and they are known as trans-resonance can intensify the metabolic rate. In turn, certain EMW frequency regimes (they are not transparent for the water and the water-containing tissues, and they are called as non-resonance can disturb the native electro-magnetic status of the cells and can lead to morphological changes in organs. Morphological changes in adrenal glands and cortizol level of 60 White Vistar rats (males in serum under transparent EMW frequency regimes and non-transparent ones were examined. Transparent and non-transparent frequency regimes impact the various changes in adrenals. Cortizol level corresponds to morphologic conclusion. Stress modified EMW-effects in both variants - under resonance and non-resonance EMW frequency regimes in adrenal morphology and cortizol level.

  17. Electromagnetically induced transparency metamaterial based on spoof localized surface plasmons at terahertz frequencies

    Science.gov (United States)

    Liao, Zhen; Liu, Shuo; Ma, Hui Feng; Li, Chun; Jin, Biaobing; Cui, Tie Jun

    2016-06-01

    We numerically and experimentally demonstrate a plasmonic metamaterial whose unit cell is composed of an ultrathin metallic disk and four ultrathin metallic spiral arms at terahertz frequencies, which supports both spoof electric and magnetic localized surface plasmon (LSP) resonances. We show that the resonant wavelength is much larger than the size of the unit particle, and further find that the resonant wavelength is very sensitive to the particle’s geometrical dimensions and arrangements. It is clearly illustrated that the magnetic LSP resonance exhibits strong dependence to the incidence angle of terahertz wave, which enables the design of metamaterials to achieve an electromagnetically induced transparency effect in the terahertz frequencies. This work opens up the possibility to apply for the surface plasmons in functional devices in the terahertz band.

  18. [Membranotropic effects of electromagnetic radiation of extremely high frequency on Escherichia coli].

    Science.gov (United States)

    Trchunian, A; Ogandzhanian, E; Sarkisian, E; Gonian, S; Oganesian, A; Oganesian, S

    2001-01-01

    It was found that "sound" electromagnetic radiations of extremely high frequencies (53.5-68 GHz) or millimeter waves (wavelength range of 4.2-5.6 mm) of low intensity (power density 0.01 mW) have a bactericidal effect on Escherichia coli bacteria. It was shown that exposure to irradiation of extremely high frequencies increases the electrokinetic potential and surface change density of bacteria and decreases of membrane potential. The total secretion of hydrogen ions was suppressed, the H+ flux from the cytoplasm to medium decreased, and the flux of N,N'-dicyclohexylcarbodiimide-sensitive potassium ions increased, which was accompanied by changes in the stoichiometry of these fluxes and an increase in the sensitivity of H+ ions to N,N'-dicyclohexylcarbodiimide. The effects depended on duration of exposure: as the time of exposure increased, the bactericidal effect increased, whereas the membranotropic effects decreased. The effects also depended on growth phase of bacteria: the irradiation affected the cells in the stationary but not in the logarithmic phase. It is assumed that the H(+)-ATPase complex F0F1 is involved in membranotropic effects of electromagnetic radiation of extremely high frequencies. Presumably, there are some compensatory mechanisms that eliminate the membranotropic effects.

  19. In-plane propagation of electromagnetic waves in planar metamaterials

    Science.gov (United States)

    Yi, Changhyun; Rhee, Joo Yull; Kim, Ki Won; Lee, YoungPak

    2016-08-01

    Some planar metamaterials (MMs) or subwavelength antenna/hole arrays have a considerable amount of in-plane propagation when certain conditions are met. In this paper, the in-plane propagation caused by a wave incident on a MM absorber was studied by using a finite-difference time-domain (FDTD) technique. By using a FDTD simulation, we were able to observe a nonnegligible amount of in-plane propagation after the incident wave had arrived at the surface of the planar structure and gradually decreased propagation of the electromagnetic wave in the planar direction gradually decreased. We performed the FDTD simulation carefully to reproduce valid results and to verify the existence of in-plane propagation. For verification of the in-plane propagation explicitly, Poynting vectors were calculated and visualized inside the dielectric substrate between the metallic back-plate and an array of square patches. We also investigated several different structures with resonators of various shapes and found that the amount of facing edges of adjacent metallic patches critically determined the strength of the in-plane propagation. Through this study, we could establish the basis for the existence of in-plane propagation in MMs.

  20. FDTD Simulation on Power Absorption of Terahertz Electromagnetic Waves in Dense Plasma%FDTD Simulation on Power Absorption of Terahertz Electromagnetic Waves in Dense Plasma

    Institute of Scientific and Technical Information of China (English)

    奚衍斌; 刘悦

    2012-01-01

    A finite difference time domain (FDTD) method is used to numerically study the power absorption of broadband terahertz (0.1 - 1.5 THz) electromagnetic waves in a partially ionized uniform plasma layer under low pressure and atmosphere discharge conditions. The power absorption spectra are calculated numerically and the numerical results are in accordance with the analytic results. Meanwhile, the effects on the power absorption are calculated with different applied magnetic fields, collision frequencies and electron number densities, which depend strongly on those parameters. Under the dense strongly magnetized plasma conditions, the absorption gaps appear in the range of 0.3 - 0.36 THz, and are enlarged with the increasing electron number density.

  1. Stimulated scattering of electromagnetic waves carrying orbital angular momentum in quantum plasmas.

    Science.gov (United States)

    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.

  2. Effect of Low Frequency Electromagnetic Field on Macrosegregation of Horizontal Direct Chill Casting Aluminum Alloys

    Institute of Scientific and Technical Information of China (English)

    Zhihao ZHAO; Jianzhong CUI; Jie DONG; Beijiang ZHANG

    2005-01-01

    The horizontal direct chill (HDC) casting process is a well-established production route for aluminum alloy ingot but the ingot may suffer from macrosegregation sometimes. In order to control the defect, a low frequency electromagnetic field has been applied in HDC casting process and the relevant influence has been studied. The results show that application of low frequency electromagnetic field can reduce macrosegregation in HDC casting process; and two main parameters of electromagnetic field density and frequency, have great influences on the solution distribution along the diameter of ingot. Moreover, the mechanisms of reduction of macrosegregation by electromagnetic field have been discussed.

  3. Finite Element Modeling of scattered electromagnetic waves for stroke analysis.

    Science.gov (United States)

    Priyadarshini, N; Rajkumar, E R

    2013-01-01

    Stroke has become one of the leading causes of mortality worldwide and about 800 in every 100,000 people suffer from stroke each year. The occurrence of stroke is ranked third among the causes of acute death and first among the causes for neurological dysfunction. Currently, Neurological examinations followed by medical imaging with CT, MRI or Angiography are used to provide better identification of the location and the type of the stroke, however they are neither fast, cost-effective nor portable. Microwave technology has emerged to complement these modalities to diagnose stroke as it is sensitive to the differences between the distinct dielectric properties of the brain tissues and blood. This paper investigates the possibility of diagnosing the type of stroke using Finite Element Analysis (FEA). The object of interest is a simulated head phantom with stroke, created with its specifying material characteristics like electrical conductivity and relative permittivity. The phantom is then placed in an electromagnetic field generated by a dipole antenna radiating at 1 GHz. The FEM forward model solver computes the scattered electromagnetic field by finding the solution for the Maxwell's wave equation in the head volume. Subsequently the inverse scattering problem is solved using the Contrast Source Inversion (CSI) method to reconstruct the dielectric profile of the head phantom.

  4. Searching for electromagnetic counterparts of gravitational wave transients

    CERN Document Server

    Branchesi, M; Laas-Bourez, M

    2011-01-01

    A pioneering electromagnetic (EM) observation follow-up program of candidate gravitational wave (GW) triggers has been performed, Dec 17 2009 to Jan 8 2010 and Sep 4 to Oct 20 2010, during the recent LIGO/Virgo run. The follow-up program involved ground-based and space EM facilities observing the sky at optical, X-ray and radio wavelengths. The joint GW/EM observation study requires the development of specific image analysis procedures able to discriminate the possible EM counterpart of GW trigger from background events. The paper shows an overview of the EM follow-up program and the developing image analysis procedures as they are applied to data collected with TAROT and Zadko.

  5. Atmospheric Refractive Electromagnetic Wave Bending and Propagation Delay

    CERN Document Server

    Mangum, Jeffrey G

    2014-01-01

    In this tutorial we summarize the physics and mathematics behind refractive electromagnetic wave bending and delay. Refractive bending and delay through the Earth's atmosphere at both radio/millimetric and optical/IR wavelengths are discussed, but with most emphasis on the former, and with Atacama Large Millimeter Array (ALMA) applications in mind. As modern astronomical measurements often require sub-arcsecond position accuracy, care is required when selecting refractive bending and delay algorithms. For the spherically-uniform model atmospheres generally used for all refractive bending and delay algorithms, positional accuracies $\\lesssim 1^{\\prime\\prime}$ are achievable when observing at zenith angles $\\lesssim 75^\\circ$. A number of computationally economical approximate methods for atmospheric refractive bending and delay calculation are presented, appropriate for astronomical observations under these conditions. For observations under more realistic atmospheric conditions, for zenith angles $\\gtrsim 75^...

  6. Quantum metamaterials: Electromagnetic waves in Josephson qubit lines

    Energy Technology Data Exchange (ETDEWEB)

    Zagoskin, A.M. [Frontier Research System, Institute of Physical and Chemical Research (RIKEN),Wako-shi, Saitama (Japan); Department of Physics, Loughborough University, Loughborough (United Kingdom); Physics and Astronomy Department, University of British Columbia, Vancouver, B.C. (Canada); Rakhmanov, A.L. [Frontier Research System, Institute of Physical and Chemical Research (RIKEN),Wako-shi, Saitama (Japan); Institute for Theoretical and Applied Electrodynamics RAS, Moscow (Russian Federation); Savel' ev, Sergey [Frontier Research System, Institute of Physical and Chemical Research (RIKEN),Wako-shi, Saitama (Japan); Department of Physics, Loughborough University, Loughborough (United Kingdom); Nori, Franco [Frontier Research System, Institute of Physical and Chemical Research (RIKEN),Wako-shi, Saitama (Japan); Department of Physics, Center for Theoretical Physics, Applied Physics Program, Center for the Study of Complex Systems, University of Michigan, Ann Arbor, MI (United States)

    2009-05-15

    We consider the propagation of a classical electromagnetic wave through a transmission line, formed by identical superconducting charge qubits inside a superconducting resonator. Since the qubits can be in a coherent superposition of quantum states, we show that such a system demonstrates interesting new effects, such as a ''breathing'' photonic crystal with an oscillating bandgap. Similar behaviour is expected from a transmission line formed by flux qubits. The key ingredient of these effects is that the optical properties of the Josephson transmission line are controlled by the quantum coherent state of the qubits (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  7. Diffraction of Electromagnetic Wave by Circular Disk and Circular Hole

    CERN Document Server

    Shahzad, Muhammad Adnan

    2010-01-01

    The problem of diffraction of an electromagnetic plane wave by a perfectly conducting circular disk and its complementary problem, diffraction by a circular hole in an infinite conducting plate, are rigorously solved using the method of the Kobayashi potential. The mathematical formulation involved dual integral equation derived from the potential integral and boundary condition on the plane where a disk or hole is located. The weighting function in the potential integral are determined by applying the properties of the Weber-Schafheitlin's discontinuous integral and the solution are obtained in the form of a matrix equation. The matrix elements of the equations for the expansion coefficients are given by three kinds of infinite integral and the series solution for these infinite integral are derived. For the verification of these series solution, the numerical integral are derived and the results are computed numerically using the method of Gaussian quadrature for conformation. The numerical results are give...

  8. Electromagnetic wave activity detected by MMS at the vicinity of the magnetopause and its relation to heating and acceleration of particles

    Science.gov (United States)

    Le Contel, Olivier; Retino, Alessandro; Breuillard, Hugo; Berthomier, Matthieu; Mirioni, Laurent; Sahraoui, Fouad; Chust, Thomas; Chasapis, Alexandros; Aunai, Nicolas; Lavraud, Benoit; Lindqvist, Per-Arne; Khotyaintsev, Yuri; Vaivads, Andris; Marklund, Goran; Ergun, Robert E.; Goodrich, Katherine; Wilder, Frederick D.; Argall, Matthew; Burch, Jim L.; Torbert, Roy B.

    2016-04-01

    In the present study, we analyze different dayside magnetopause crossings detected by the MMS mission in order to investigate the relation between the electromagnetic wave activity and particle heating/acceleration. In particular, our study is focused on two different frequency ranges: (1) 1-10 Hz range which corresponds to the frequency domain of kinetic Alfvén and lower-hybrid waves, (2) 10 Hz-1kHz which corresponds mainly to the whistler mode wave frequency domain. After characterizing the different types of waves, we estimate their respective energy content as well as their possible role for heating and accelerating the plasma.

  9. Similarity of the Doppler shifted time-symmetric electromagnetic field of a Dirac particle to the de Broglie matter wave

    CERN Document Server

    Lush, David C

    2016-01-01

    It is investigated whether the Planck-Einstein relation between the energy and frequency of light quanta, and the de Broglie wavelength of matter can be wholly or partially explained as consequences of the relativistic Doppler shift of electromagnetic fields caused by oscillating electric dipoles within the elementary particles constituting light and matter, and their electromagnetic interaction with similarly constituted particles. Assuming the oscillation is at the zitterbewegung frequency of the Dirac electron theory, the photon energy is found to be approximately half the value expected according to the Planck-Einstein relation. The relativistically Doppler shifted time-symmetric electromagnetic field due to the particle is found to have a superluminal phase velocity equal to that of the de Broglie matter wave, a group velocity equal to the particle velocity, and a wavelength of \\(h/p\\).

  10. High frequency electromagnetic processes in induction motors supplied from PWM inverters

    Directory of Open Access Journals (Sweden)

    Ioan Ţilea

    2010-12-01

    Full Text Available The paper presents the electromagnetic interference between induction motors and inverters when at high frequency electromagnetic process appears in induction motors having a parallel resonant effect because of parasitic capacitive coupling between windings and ground, using a numerical model in simulink and a high frequency induction motor equivalent circuit model this effect is shown.

  11. Resonant response of a strong electromagnetic wave beam to a gravitational wave in a static magnetic field

    Institute of Scientific and Technical Information of China (English)

    LI; Fangyu

    2001-01-01

    [1]Gerlach, U. H., Cavity quantum-electrodynamical response to a gravitational wave, Phys. Rev. D, 1992, 46: 1 239.[2]Fortini, P., Gualdi, C., Ortolan, A., Interaction of a gravitational wave with electromagnetic currents, Nuovo Cimento B, 1991,106: 395.[3]Cuomo, D., Franceschetti, G., Panariello, G. et al., Proceeding of International Symposium on Experimental Gravitational Physics, Guangzhou, China (ed. Michelson, F. C.), Singapore: World Scientific, 1992, 262.[4]Logi, W. K., Mickelson, A. R., Electrogravitational conversion cross section in static electromagnetic fields, Phys. Rev. D, 1977, 16: 2 915.[5]Long, H. N., Soa, D. V., Tuan, T. A., The conversion of gravitons into photons in a periodic external electromagnetic field, Phys. Lett. A, 1994, 186: 382.[6]Boccaletti, D., Sabbata, V. D., Fortini, P., Conversion of photons into gravitons and vice versa in a static electromagnetic field, Nuovo Cimento B, 1970, 70: 129.[7]Grishchuk, L. P., Sazhin, M. V., Excitation and detection of standing gravitational waves, Sov. Phys. Jetp, 1975, 41: 787.[8]Gratta, G., Kim, K. J., Melissions, A. et al., Workshop on Beam-Beam and Beam-Radiation Interaction: High Intensity and Nonlinear Effects, Los Angeles, USA (ed. Pellegrini, C.), Singapore: World Scientific, 1992, 70.[9]Chen, P., Palazzi, G. D., Kim, K. J. et al., Workshop on Beam-Beam and Beam-Radiation Interaction: High Intensity and Nonlinear Effects, Los Angeles, USA (ed. Pellegrini, C.), Singapore: World Scientific, 1992, 84.[10]Grishchuk, L. P., Sazhin, M. V., Squeezed quantum states of a harmonic oscillator in the problem of gravitational wave detection. Sov. Phys. Jetp, 1983, 53: 1128.[11]Tang, M. X., Li, F. Y., Luo, J., High frequency gravitational wave of a composite toroidal electrodrynamical resonant system, Acta Physical Sinica, 1997, 6: 161.[12]Li, F. Y., Tang, M. X., Coherent resonant of a strong electromagnetic wave beam to a standing gravitational wave

  12. Application of electromagnetic waves in damage detection of concrete structures

    Science.gov (United States)

    Feng, Maria Q.; De Flaviis, Franco; Kim, Yoo J.; Diaz, Rodolfo E.

    2000-04-01

    Jacketing technology using fiber reinforced polymer (FRP) composites is being applied for seismic retrofit of reinforced concrete (RC) columns designed and constructed under older specifications. In this study, the authors develop an electromagnetic (EM) imaging technology for detecting voids and debonding between the jacket and the column, which may significantly weaken the structural performance of the column otherwise attainable by jacketing. This technology is based on the reflection analysis of a continuous EM wave sent toward and reflected from layered FRP-adhesive-concrete medium: Poor bonding conditions including voids and debonding will generate air gaps which produce additional reflections of the EM wave. In this study, dielectric properties of various materials involved in the FRP-jacketed RC column were first measured. Second, the measured properties were used for a computer simulation of the proposed EM imaging technology. The simulation demonstrated the difficulty in detecting imperfect bonding conditions by using plane waves, as the scattering contribution from the voids and debonding is very small compared to that from the jacketed column. Third, in order to alleviate this difficulty, a special dielectric lens was designed and fabricated to focus the EM wave on the bonding interface. Furthermore, the time gating technique is used in order to reduce the noise resulting from various uncertainties associated with the jacketed columns. Finally, three concrete columns were constructed and wrapped with glass-FRP jackets with various voids and debonding condition artificially introduced in the bonding interface. Using the proposed EM imaging technology with the lens especially designed and installed, these voids and debonding condition were successfully detected.

  13. Analog electromagnetically induced transparency for circularly polarized wave using three dimensional chiral metamaterials

    CERN Document Server

    Lin, Hai; Han, Song; Liu, Yangjie; Yang, Helin

    2016-01-01

    In this paper, we theoretically and experimentally demonstrate a three dimensional metamaterial that can motivate electromagnetic induced transparency (EIT) by using circular polarized wave as stimulations. The unit cell consists of a pair of metallic strips printed on both sides of the printed circuit board (PCB), where a conductive cylinder junction is used to connect the metal strips by drilling a hole inside the substrate. When a right circularly polarized wave is incident, destructive interference is excited between meta-atoms of the 3D structure, the transmission spectrum demonstrates a sharp transparency window. A coupled oscillator model and an electrical equivalent circuit model are applied to quantitatively and qualitatively analyze the coupling mechanism in the EIT-like metamaterial. Analysis in detail shows the EIT window's amplitude and frequency are modulated by changing the degree of symmetry breaking. The proposed metamaterial may achieve potential applications in developing chiral slow light ...

  14. Low Frequency Radio-wave System for subsurface investigation

    Science.gov (United States)

    Soldovieri, Francesco; Gennarelli, Gianluca; Kudelya, Anatoliy; Denisov, Alexander

    2015-04-01

    Low frequency radio-wave methods (RWM) allow subsurface investigations in terms of lithological structure characterization, detection of filtration flows of ground water, anthropogenic and natural cavities. In this contribution, we present a RWM that exploits two coils working at frequencies of few MHz as transmitting and receiving antennas. The basic principle of this inductive method is as follows. The primary alternating electromagnetic field radiated by the transmitting coil induces eddy currents in the subsurface mainly due to the conductivity anomalies. These eddy currents generate a secondary (scattered) magnetic field which overlaps to the incident magnetic field and is detected by the receiving coil. Despite the simple operation of the system, the complexity of the electromagnetic scattering phenomenon at hand must be properly modeled to achieve adequate performance. Therefore, an advanced data processing technique, belonging to the class of the inverse scattering approaches, has been developed by the authors in a full 3D geometry. The proposed method allows to deal with data collected on a scanning surface under a dipole inductive profiling (DIP) modality, where the transmitting/receiving coils are moved simultaneously with fixed offset (multi-bistatic configuration). The hardware, called Dipole Inductive Radio-wave System (DIRS), is composed by an electronic unit and transmitting and receiving loop antennas radiating at frequencies of few MHz (2-4 MHz), which are installed on theodolite supports. The compactness of DIRS and its robustness to external electromagnetic interference offers the possibility to perform geophysical research up to the depth of some tens of meters and under several types of ground and water surfaces, vegetation, and weather conditions. The light weight and small size of system (the single antenna with support weights about 5 kg and has a diameter of 0.5m) allows two operators to perform geophysical research without disturbing the

  15. Diffusive and localization behavior of electromagnetic waves in a two-dimensional random medium.

    Science.gov (United States)

    Wang, Ken Kang-Hsin; Ye, Zhen

    2003-10-01

    In this paper, we discuss the transport phenomena of electromagnetic waves in a two-dimensional random system which is composed of arrays of electrical dipoles, following the model presented earlier by Erdogan et al. [J. Opt. Soc. Am. B 10, 391 (1993)]. A set of self-consistent equations is presented, accounting for the multiple scattering in the system, and is then solved numerically. A strong localization regime is discovered in the frequency domain. The transport properties within, near the edge of, and nearly outside the localization regime are investigated for different parameters such as filling factor and system size. The results show that within the localization regime, waves are trapped near the transmitting source. Meanwhile, the diffusive waves follow an intuitive but expected picture. That is, they increase with traveling path as more and more random scattering incurs, followed by a saturation, then start to decay exponentially when the travelling path is large enough, signifying the localization effect. For the cases where the frequencies are near the boundary of or outside the localization regime, the results of diffusive waves are compared with the diffusion approximation, showing less encouraging agreement as in other systems [Asatryan et al., Phys. Rev. E 67, 036605 (2003)].

  16. Scattering of mid-IR-range surface electromagnetic waves by optically smooth metal surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Bonch-Bruevich, A.M.; Libenson, M.N.; Makin, V.S.; Pudkov, S.D.; Trubaev, V.V.

    1985-09-01

    The paper reports the experimental observation of the intense scattering of surface electromagnetic waves with a wavelength of 10.6 microns excited on an optically smooth metal surface with a residual roughness having a mean square height of less than 25 A. A method for determining the attenuation of surface electromagnetic waves is proposed, and a test of the method is reported which involves the measurement of the relative intensity of the local scattering of the waves along their path. 9 references.

  17. Electron acceleration in the ionosphere by obliquely propagating electromagnetic waves

    Energy Technology Data Exchange (ETDEWEB)

    Burke, W.J.; Ginet, G.P.; Heinemann, M.A.; Villalon, E.

    1988-01-01

    The relativistic equations of motion have been analyzed for electrons in magnetized plasmas and externally imposed electromagnetic fields that propagate at arbitrary angles to the background magnetic field. The electron energy is obtained from a set of non-linear differential equations as functions of time, initial conditions and cyclotron harmonic numbers. For a given cyclotron resonance the energy oscillates in time within the limits of a potential well. Stochastic acceleration occurs if the widths of hamiltonian potentials overlap. Numerical analyses suggest that, at wave energy fluxes in excess of 10/sup 8/ mW/m/sup 2/, initially cold electrons can be accelerated to energies of several MeV in less than a millisecond. Practical attempts to validate the theory with a series of planned rocket flights over the HIPAS facility in Alaska are discussed. The HIPAS antennas will be used to irradiate the magnetic mirror points of 10 - 40 keV electrons emitted from the ECHO 7 rocket in the early winter of 1988. Follow-on rocket experiments to exploit the wave amplification properties of the ionospheric 'radio window' are described.

  18. Interaction of High Intensity Electromagnetic Waves with Plasmas

    Energy Technology Data Exchange (ETDEWEB)

    G. Shvets

    2008-10-03

    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.

  19. Sub-millimeter wave frequency heterodyne detector system

    Science.gov (United States)

    Siegel, Peter H. (Inventor); Dengler, Robert (Inventor); Mueller, Eric R. (Inventor)

    2010-01-01

    The present invention relates to sub-millimeter wave frequency heterodyne imaging systems. More specifically, the present invention relates to a sub-millimeter wave frequency heterodyne detector system for imaging the magnitude and phase of transmitted power through or reflected power off of mechanically scanned samples at sub-millimeter wave frequencies.

  20. Ponderomotive modification of multicomponent magnetospheric plasma due to electromagnetic ion cyclotron waves

    CERN Document Server

    Nekrasov, A K

    2013-01-01

    We derive the expression for the ponderomotive force in the real multicomponent magnetospheric plasma containing heavy ions. The ponderomotive force considered includes the induced magnetic moment of all the species and arises due to inhomogeneity of the traveling low-frequency electromagnetic wave amplitude in the nonuniform medium. The nonlinear stationary force balance equation is obtained taking into account the gravitational and centrifugal forces for the plasma consisting of the electrons, protons and heavy ions (He$^{+}$). The background geomagnetic field is taken for the dayside of the magnetosphere, where the magnetic field have magnetic "holes" (Antonova and Shabansky 1968). The balance equation is solved numerically to obtain the nonlinear density distribution of ions (H$^{+}$) in the presence of heavy ions (He$^{+}$). It is shown that for frequencies less than the helium gyrofrequency at the equator the nonlinear plasma density perturbations are peaked in the vicinity of the equator due to the act...

  1. Harvesting Broad Frequency Band Blue Energy by a Triboelectric-Electromagnetic Hybrid Nanogenerator.

    Science.gov (United States)

    Wen, Zhen; Guo, Hengyu; Zi, Yunlong; Yeh, Min-Hsin; Wang, Xin; Deng, Jianan; Wang, Jie; Li, Shengming; Hu, Chenguo; Zhu, Liping; Wang, Zhong Lin

    2016-07-26

    Ocean wave associated energy is huge, but it has little use toward world energy. Although such blue energy is capable of meeting all of our energy needs, there is no effective way to harvest it due to its low frequency and irregular amplitude, which may restrict the application of traditional power generators. In this work, we report a hybrid nanogenerator that consists of a spiral-interdigitated-electrode triboelectric nanogenerator (S-TENG) and a wrap-around electromagnetic generator (W-EMG) for harvesting ocean energy. In this design, the S-TENG can be fully isolated from the external environment through packaging and indirectly driven by the noncontact attractive forces between pairs of magnets, and W-EMG can be easily hybridized. Notably, the hybrid nanogenerator could generate electricity under either rotation mode or fluctuation mode to collect energy in ocean tide, current, and wave energy due to the unique structural design. In addition, the characteristics and advantages of outputs indicate that the S-TENG is irreplaceable for harvesting low rotation speeds (10 Hz). The complementary output can be maximized and hybridized for harvesting energy in a broad frequency range. Finally, a single hybrid nanogenerator unit was demonstrated to harvest blue energy as a practical power source to drive several LEDs under different simulated water wave conditions. We also proposed a blue energy harvesting system floating on the ocean surface that could simultaneously harvest wind, solar, and wave energy. The proposed hybrid nanogenerator renders an effective and sustainable progress in practical applications of the hybrid nanogenerator toward harvesting water wave energy offered by nature.

  2. Risk perception and public concerns of electromagnetic waves from cellular phones in Korea.

    Science.gov (United States)

    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.

  3. Effect Of Electromagnetic Waves Emitted From Mobile Phone On Brain Stem Auditory Evoked Potential In Adult Males.

    Science.gov (United States)

    Singh, K

    2015-01-01

    Mobile phone (MP) is commonly used communication tool. Electromagnetic waves (EMWs) emitted from MP may have potential health hazards. So, it was planned to study the effect of electromagnetic waves (EMWs) emitted from the mobile phone on brainstem auditory evoked potential (BAEP) in male subjects in the age group of 20-40 years. BAEPs were recorded using standard method of 10-20 system of electrode placement and sound click stimuli of specified intensity, duration and frequency.Right ear was exposed to EMW emitted from MP for about 10 min. On comparison of before and after exposure to MP in right ear (found to be dominating ear), there was significant increase in latency of II, III (p wave, amplitude of I-Ia wave (p wave (P waves of BAEP in left ear before vs after MP. On comparison of right (having exposure routinely as found to be dominating ear) and left ears (not exposed to MP), before exposure to MP, IPL of IIl-V wave and amplitude of V-Va is more (wave (< 0.001) in left ear. After exposure to MP, the amplitude of V-Va was (p < 0.05) more in right ear compared to left ear. In conclusion, EMWs emitted from MP affects the auditory potential.

  4. Nonlinear interactions of electromagnetic waves with the auroral ionosphere

    Science.gov (United States)

    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.

  5. Nanostructured Barium Titanate/Carbon Nanotubes Incorporated Polyaniline as Synergistic Electromagnetic Wave Absorbers

    Directory of Open Access Journals (Sweden)

    Lujun Yu

    2016-01-01

    Full Text Available The three-dimensional (3D conductive network structures formed by barium titanate/carbon nanotubes incorporated polyaniline were favorable for strengthening electromagnetic absorption capability. Herein, an easy and flexible method consisting of sol-gel technique, in situ polymerization, and subsequent mechanical method have been developed to prepare the barium titanate/carbon nanotubes incorporated polyaniline (CNTs/BaTiO3/PANI or CBP ternary composites. The dielectric properties and microwave absorption properties of CNTs/BaTiO3/PANI composites were investigated in the frequency range of 2–18 GHz by vector network analyzer. Interestingly, it is found that the CNTs/BaTiO3/PANI composites with 3D conductive network structures presented outstanding electromagnetic absorption properties, which may be attributed to the high impedance matching behavior and improved dielectric loss ability and novel synergistic effect. Additionally, it also can be supposed that the “geometrical effect” of composite was more beneficial to absorbing the incident electromagnetic wave. The CNTs/BaTiO3/PANI composite (the mass ratio of CNTs/BaTiO3 to PANI is 2 : 3 exhibits the best microwave absorption properties, of which the minimum reflection loss value can reach −30.9 dB at 8 GHz and the absorption bandwidth with a reflection loss blew −10 dB ranges from 7.5 to 10.2 GHz.

  6. A review of nondestructive testing approaches using mechanical and electromagnetic waves

    Science.gov (United States)

    Lau, Denvid; Qiu, Qiwen

    2016-04-01

    Mechanical and electromagnetic waves are commonly used in nondestructive testing (NDT) techniques for evaluating the materials and structures in civil engineering industry, due to their good examination of defects inside the matter. However, the individual use of mechanical wave or electromagnetic wave in NDT methods sometimes does not fulfill the satisfactory detection in practice because of the operational inconvenience and low sensitivity. It has been demonstrated that the combination of using both types of waves can achieve a better performance for NDT application and would be the future direction for defect detection, as the advantages of each physical wave are picked out whereas the weaknesses are mitigated. This paper discusses the fundamental mechanisms and the current applications of using mechanical and electromagnetic waves for defect detection, with the goal of providing the physical knowledge and the perspectives of developing the NDT applications with these two types of waves. Typical mechanical-wave-based NDT methods such as acoustic emission, ultrasonic technique, and impact-echo method are reviewed. In addition, NDT methods using electromagnetic wave, which include optical fiber sensing technique, laser speckle interferometry and laser reflection technique are discussed. Advantages and disadvantages of these methods are outlined. In particular, we focus on a recent NDT method called acoustic-laser technique, which utilizes both the mechanical and electromagnetic waves. The basic principles and some important experimental data recorded by the acoustic-laser technique are described and its future development in the field of defect detection in civil infrastructure is presented.

  7. Generation and detection of gravitational waves at microwave frequencies by means of a superconducting two-body system

    CERN Document Server

    Chiao, Raymond Y

    2007-01-01

    The 2-body system of a superconducting sphere levitated in the magnetic field generated by a persistent current in a superconducting ring, can possibly convert gravitational waves into electromagnetic waves, and vice versa. Faraday's law of induction implies that the time-varying distance between the sphere and the ring caused by the tidal force of an incident gravitational wave induces time-varying electrical currents, which are the source of an electromagnetic wave at the same frequency as the incident gravitational wave. At sufficiently low temperatures, the internal degrees of freedom of the superconductors are frozen out because of the superconducting energy gap, and only external degrees of freedom, which are coupled to the radiation fields, remain. Hence this wave-conversion process is loss-free and therefore efficient, and by time-reversal symmetry, so is the reverse process. A Hertz-like experiment at microwave frequencies should therefore be practical to perform. This would open up observations of t...

  8. Low-Frequency Electromagnetic Sounding for Planetary Volatiles (Invited)

    Science.gov (United States)

    Grimm, R. E.

    2013-12-01

    EM sounding is divided by loss tangent penetrating radars) and >> 1 (inductive methods). The former have high resolution and responses dominated by dielectric permittivity. They have been useful for sounding the polar caps of Mars and are very promising to image the shells of icy satellites as well as the uppermost crusts of silicate bodies. The latter have poorer resolution but greater penetration depth, responses dominated by electrical conductivity, and are the subject of this talk. Low-frequency inductive methods are further divided by comparing the source-receiver separation to the skin depth. Large separations are parametric in frequency so that the variation of EM response with frequency is translated to change in conductivity with depth. Parametric soundings can exploit natural sources from the solar wind, magnetosphere, ionosphere, or atmosphere. Small source-sensor separations are geometric with transmitter-receiver positions: both conductivity and permittivity can be recovered as a function of frequency (a dielectric spectrum), but at greater resource requirements. Subsurface liquid water is an optimal low-frequency EM target because even small quantities of dissolved ions make it a powerful electrical conductor compared to dry, resistive, silicate crusts. Water at kms or even tens of kms can be detected using the magnetotelluric, geomagnetic-depth sounding, or wave-tilt methods: these are all natural-source soundings using different combinations of field components and receiver geometries. If natural sources are weak or absent, a transmitter can be used to obtain high SNR; the time-domain EM (TDEM) method has been used extensively for terrestrial groundwater exploration. Using a ballistically deployed 200-m diameter transmitter loop, TDEM can detect groundwater at depths of several km. If landed in a region of strong local crustal magnetism, the characteristic Larmor frequency of liquid water can be detected with a TDEM-like setup using nuclear magnetic

  9. Metamaterials, from electromagnetic waves to water waves, bending waves and beyond

    KAUST Repository

    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.

  10. A wave guide model of lightning currents and their electromagnetic field

    Science.gov (United States)

    Volland, H.

    1980-01-01

    Lightning channels are considered as resonant wave guides in which only standing resonant wave modes can be excited. Two types of discharging currents develop. Type 1 is an aperiodic wave; type 2 is a damped oscillation. The electromagnetic radiation field of both types of currents is calculated and compared with the observation.

  11. Photo-Ionization of Hydrogen Atom in a Circularly Polarized Standing Electromagnetic Wave

    Institute of Scientific and Technical Information of China (English)

    LIU Xiang-Tao; ZHANG Qi-Ren; WANG Wan-Zhang

    2004-01-01

    Applying time-independent non-perturbative formalism to the photo-ionization of hydrogen atom immersed in a strong circularly polarized standing electromagnetic wave, we calculate the shift of energy levels and the distortion of wave functions for the hydrogen atom, the ionization cross section induced by the standing wave, and the angular distribution of photoelectrons and obtain some interesting results.

  12. Damping and scattering of electromagnetic waves by small ferrite spheres suspended in an insulator

    Science.gov (United States)

    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.

  13. Doppler Frequency Shift in Ocean Wave Measurements: Frequency Downshift of a Fixed Spectral Wave Number Component by Advection of Wave Orbital Velocity

    National Research Council Canada - National Science Library

    Hwang, Paul

    2006-01-01

    ... expected intrinsic frequency in the frequency spectrum measured by a stationary probe. The advection of the wave number component by the orbital current of background waves produces a net downshift in the encounter frequency...

  14. Excitation of surface electromagnetic waves in a graphene-based Bragg grating.

    Science.gov (United States)

    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.

  15. Observation of low frequency electromagnetic activity at 1000 km altitude

    Directory of Open Access Journals (Sweden)

    N. Ivchenko

    Full Text Available We present a statistical study of low frequency fluctuations of electric and magnetic fields, commonly interpreted as Alfvénic activity. The data base consists of six months of electric and magnetic field measurements by the Astrid-2 microsatellite. The occurrence of the events is studied with respect to the location and general activity. Large regions of broadband Alfvénic activity are persistently observed in the cusp/cleft and, during the periods of high geo-magnetic activity, also in the pre-midnight sector of the auroral oval.

    Key words. Ionosphere (auroral ionosphere – Space plasma physics (waves and instabilities – Magnetospheric physics (magnetosphere-ionosphere interactions

  16. Modeling and simulations on the propagation characteristics of electromagnetic waves in sub-atmospheric pressure plasma slab

    Science.gov (United States)

    Wang, Z. B.; Nie, Q. Y.; Li, B. W.; Kong, F. R.

    2017-01-01

    Sub-atmospheric pressure plasma slabs exhibit the feature of relatively high plasma number density and high collisional frequency between electrons and neutral gases, as well as similar thickness to the electromagnetic (EM) wavelength in communication bands. The propagation characteristics of EM waves in sub-atmospheric pressure plasma slabs are attracting much attention of the researchers due to their applications in the plasma antenna, the blackout effect during reentry, wave energy injection in the plasma, etc. In this paper, a numerical model with a one-dimensional assumption has been established and therefore, it is used for the investigations of the propagation characteristics of the EM waves in plasma slabs. In this model, the EM waves propagating in both sub-wavelength plasma slabs and plasmas with thicker slabs can be studied simultaneously, which is superior to the model with geometrical optics approximation. The influence of EM wave frequencies and collisional frequencies on the amplitude of the transmitted EM waves is discussed in typical plasma profiles. The results will be significant for deep understanding of the propagation behaviors of the EM waves in sub-atmospheric pressure nonuniform plasma slabs, as well as the applications of the interactions between EM waves and the sub-atmospheric pressure plasmas.

  17. Vlasov - Maxwell, Self-consistent Electromagnetic Wave Emission Simulations in the Solar Corona

    Science.gov (United States)

    Tsiklauri, David

    2010-12-01

    1.5D Vlasov - Maxwell simulations are employed to model electromagnetic emission generation in a fully self-consistent plasma kinetic model for the first time in the context of solar physics. The simulations mimic the plasma emission mechanism and Larmor-drift instability in a plasma thread that connects the Sun to Earth with the spatial scales compressed appropriately. The effects of spatial density gradients on the generation of electromagnetic radiation are investigated. It is shown that a 1.5D inhomogeneous plasma with a uniform background magnetic field directed transverse to the density gradient is aperiodically unstable to the Larmor-drift instability. The latter results in a novel effect of generation of electromagnetic emission at plasma frequency. The generated perturbations consist of two parts: i) non-escaping (trapped) Langmuir type oscillations, which are localised in the regions of density inhomogeneity, and are highly filamentary, with the period of appearance of the filaments close to electron plasma frequency in the dense regions; and ii) escaping electromagnetic radiation with phase speeds close to the speed of light. When the density gradient is removed ( i.e. when plasma becomes stable to the Larmor-drift instability) and a low density super-thermal, hot beam is injected along the domain, in the direction perpendicular to the magnetic field, the plasma emission mechanism generates non-escaping Langmuir type oscillations, which in turn generate escaping electromagnetic radiation. It is found that in the spatial location where the beam is injected, standing waves, oscillating at the plasma frequency, are excited. These can be used to interpret the horizontal strips (the narrow-band line emission) observed in some dynamical spectra. Predictions of quasilinear theory are: i) the electron free streaming and ii) the long relaxation time of the beam, in accord with the analytic expressions. These are corroborated via direct, fully-kinetic simulation

  18. Low frequency magnetic signals associated with Langmuir waves

    Science.gov (United States)

    Kellogg, Paul J.; Goetz, K.; Lin, N.; Monson, S. J.; Balogh, A.; Forsyth, R. J.; Stone, R. G.

    1992-01-01

    With the URAP experiment on Ulysses, low frequency signals with a magnetic component in close time correlation with electrostatic Langmuir waves at the plasma frequency are observed. In most, if not all, of these cases, the Langmuir waves are part of a Type III solar burst. This effect is investigated and it is shown that the low frequency waves are in the whistler mode and are most likely due to nonlinear effects involving Langmuir waves.

  19. High-frequency capillary waves excited by oscillating microbubbles

    CERN Document Server

    Pommella, Angelo; Poulichet, Vincent; Garbin, Valeria

    2013-01-01

    This fluid dynamics video shows high-frequency capillary waves excited by the volumetric oscillations of microbubbles near a free surface. The frequency of the capillary waves is controlled by the oscillation frequency of the microbubbles, which are driven by an ultrasound field. Radial capillary waves produced by single bubbles and interference patterns generated by the superposition of capillary waves from multiple bubbles are shown.

  20. Excitation of electrostatic waves in the electron cyclotron frequency range during magnetic reconnection in laboratory overdense plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Kuwahata, A., E-mail: kuwahata@ts.t.u-tokyo.ac.jp [Graduate School of Engineering, The University of Tokyo, Tokyo 113-8656 (Japan); Igami, H. [National Institute for Fusion Science, Toki 509-5292 (Japan); Kawamori, E. [Institute of Space and Plasma Sciences, National Cheng Kung University, Tainan 70101, Taiwan (China); Kogi, Y. [Fukuoka Institute of Technology, Fukuoka 811-0295 (Japan); Inomoto, M.; Ono, Y. [Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa 277-8561 (Japan)

    2014-10-15

    We report the observation of electromagnetic radiation at high harmonics of the electron cyclotron frequency that was considered to be converted from electrostatic waves called electron Bernstein waves (EBWs) during magnetic reconnection in laboratory overdense plasmas. The excitation of EBWs was attributed to the thermalization of electrons accelerated by the reconnection electric field around the X-point. The radiative process discussed here is an acceptable explanation for observed radio waves pulsation associated with major flares.

  1. Application of nano material for shielding power-frequency electromagnetic field

    Science.gov (United States)

    Li, Hualiang; Li, Li; Liu, Jiawen

    2015-07-01

    Only limited data are available on shielding electromagnetic field exposure in professional work. In our paper, we studied the electromagnetic field intensity in 500 kV substations, and explored influence of nanomaterial in high voltage laboratory simulation. Moreover, the results of nano-fabrics material for shielding power frequency electromagnetic field indicated that, both shielding fabrics can almost completely shield the electric field, but have weak shielding effectiveness against magnetic field.

  2. Safety Problems of Electric and Magnetic Fields and Experimental Magnetic Fusion Facilities 4.Biolosical Effects of High-Frequency Electromagnetic Fields

    Science.gov (United States)

    Fujiwara, Osamu

    With the expanding use of portable telephones, public concerns regarding potential health hazards due to the absorption of electromagnetic energy have been growing. In this article, electromagnetic waves and their resultant biological effects are reviewed. The thermal effects due to RF (radio-frequency) electromagnetic fields and basic proposals for safety standards are described in conjunction with whole-body / localized average SARs (specific absorption rates) being used as bioeffect evaluation measures. Our computed dosimetries of the human head for portable telephones are also shown.

  3. High resolution electromagnetic methods and low frequency dispersion of rock conductivity

    Directory of Open Access Journals (Sweden)

    V. V. Ageev

    1999-06-01

    Full Text Available The influence of frequency dispersion of conductivity (induced polarization of rocks on the results of electromagnetic (EM sounding was studied on the basis of calculation of electric field of vertical magnetic dipole above horizontally layered polarizable sections. Frequency dispersion was approximated by the Debye formula. Polarizable homogeneous halfspace, two, three and multilayered sections were analyzed in frequency and time domains. The calculations for different values of chargeability and time constants of polarization were performed. In the far zone of a source, the IP of rocks led to quasi-wave phenomena. They produced rapid fluctuations of frequency and transient sounding curves (interference phenomena, multireflections in polarizable layers. In the case of transient sounding in the near zone of a source quasistatic distortions prevailed, caused by the counter electromotive force arising in polarizable layers which may lead to strong changes in transient curves. In some cases quasiwave and quasistatic phenomena made EM sounding curves non-interpretable in the class of quasistationary curves over non-dispersive sections. On the other hand, they could increase the resolution and depth of investigation of EM sounding. This was confirmed by an experience of "high-resolution" electroprospecting in Russia. The problem of interpretation of EM sounding data in polarizable sections is nonunique. To achieve uniqueness it is probably necessary to complement them by soundings of other type.

  4. Radiation reaction dynamics in an electromagnetic wave and constant electric field

    Science.gov (United States)

    Atlee Jackson, E.

    1984-05-01

    The relativistic motion of a charged particle is studied when it is acted on simultaneously by a constant electric field and a plane electromagnetic wave, propagating in the direction of the electric field (x axis). The dynamics includes the radiation reaction (self-force) on the particle through a standard approximation of the Lorentz-Dirac equation. The interest is to determine the result of the competition between the average acceleration due to the electromagnetic wave (``radiation pressure'') and the acceleration due to the constant force of the static field. Each of these actions alone of course produce an unbounded particle energy asymptotically in time. However, it is proved first that, when the ``forces'' are in opposite directions, the particle can never accelerate (on the average) indefinitely in the x direction, regardless how weak the electric field (E0) is compared to the amplitude of the wave (A). It is then proved that all solutions converge to a region of zero area in a suitable velocity phase space and, if there exists a periodic solution [in the phase ξ=ω (t-x/c)] in a specified region of this phase space, then all solutions must converge to this solution asymptotically (ξ→+∞). In the case when (E0A2/ω2) has a specified bound (ω: wave frequency), an iterative method is developed which explicitly yields such a periodic solution, showing that the energy remains bounded. The direction of the average drift is determined in terms of (A,E0,ω). When the parameter (E0A2/ω2) is above this bound, a combination of numerical and analytic results are obtained which indicate that this periodic solution persists. These results indicate that all motions tend to states with bounded energy, regardless of the field strengths.

  5. A radio-frequency system for in vivo pilot experiments aimed at the studies on biological effects of electromagnetic fields.

    Science.gov (United States)

    Ardoino, Lucia; Lopresto, Vanni; Mancini, Sergio; Marino, Carmela; Pinto, Rosanna; Lovisolo, Giorgio A

    2005-08-07

    An exposure system consisting of two long transversal electromagnetic (TEM) cells, operating at a frequency of 900 MHz, is presented and discussed. The set-up allows simultaneous exposure of a significant number of animals (up to 12 mice per cell) in a blind way to a uniform plane wave at a frequency of 900 MHz, for investigating possible biological effects of exposure to electromagnetic fields produced by wireless communication systems. A heating/refrigerating system has also been designed for maintaining comfortable environmental conditions within the TEM cells during experiments. An accurate dosimetric study has been performed both numerically and by means of direct measurements on phantoms and living mice. The results have shown that good homogeneity of exposure and adequate power efficiency, in terms of whole-body specific absorption rate (SAR) per 1 W of input power, are achievable for the biological target.

  6. Interaction between electromagnetic waves and energetic particles by a realistic density model

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Using a realistic density model,we present a first study on the interactions between electromagnetic waves and energetic particles in the inner magnetosphere.Numerical calculations show that as the latitude λ increases,the number density ne increases,and resonant frequency range moves to lower pitch angles.During L-mode/electron and L-mode/proton interactions,the pitch angle diffusion dominates over the momentum diffusion.This indicates that L-mode waves are primarily responsible for pitch angle scattering.For R-mode/electron interaction,the momentum diffusion is found to be comparable to the pitch angle diffusion,implying that R-mode waves can play an important role in both pitch angle scattering and stochastic acceleration of electrons.For R-mode/proton interaction,diffusion coefficients locate primarily below pitch angle 60° and increase as kinetic energy increases,suggesting that R-mode waves have potential for pitch angle scattering of highly energetic (~1 MeV) protons but cannot efficiently accelerate protons.

  7. Radiation of planar electromagnetic waves by a line source in anisotropic metamaterials

    Energy Technology Data Exchange (ETDEWEB)

    Cheng Qiang; Jiang Weixiang; Cui Tiejun, E-mail: tjcui@seu.edu.c [State Key Laboratory of Millimeter Waves, Department of Radio Engineering, Southeast University, Nanjing 210096 (China)

    2010-08-25

    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.

  8. Radiation of planar electromagnetic waves by a line source in anisotropic metamaterials

    Science.gov (United States)

    Cheng, Qiang; Jiang, Wei Xiang; Cui, Tie Jun

    2010-08-01

    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.

  9. Multi-scattering of electromagnetic waves by nanoshell aggregates

    Energy Technology Data Exchange (ETDEWEB)

    Li, Ben Q., E-mail: benqli@umich.edu [University of Michigan, Department of Mechanical Engineering (United States); Liu Changhong, E-mail: liuch@sjtu.edu.cn [Shanghai Jiao Tong University, Department of Electrical Engineering (China)

    2012-05-15

    A general analytical expression is derived for calculating the total scattering cross-section of an aggregate of nanoparticles. The approach is based on the far zone approximation and repeated use of recursive relations for Bessel functions and Legendre polynomials. In comparison with the existing formula for total scattering cross-section, the expression converges faster and makes it easier to analyze the terms that characterize the interactive coupling between nanoparticles during multiple scattering of electromagnetic waves. The expressions are valid for particle aggregates in which no two particles are in direct contact. Calculated results compare well with measurements for a nanoshell dimer. For a linear chain of particles with the chain axis parallel to the polarization direction of the electric field, analysis shows that the red-shift of resonance peaks results primarily from electrons in metal shells of two adjacent particles oscillating out-of-phase to cancel each other's radiation effects. Multi-scattering in aggregates with more complex arrangements may be explained by combining the effects of linear particle chains.

  10. 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.

  11. Locating voids beneath pavement using pulsed electromagnetic waves

    Science.gov (United States)

    Steinway, W. J.; Echard, J. D.; Luke, C. M.

    1981-11-01

    The feasibility of using pulsed electromagnetic wave technology for locating and sizing voids beneath reinforced and nonreinforced portland cement concrete pavements is determined. The data processing techniques developed can be implemented to provide information for void depth and sizing to + or - 1/2 in. and spatial location within + or - 6 in. A very short pulse radar directly connected to a microcomputer was chosen as the equipment necessary to obtain measurements. This equipment has the required accuracy and reliability, and is a cost effective solution for the void locating problem. The radar provides a signal return from voids that has unique characteristics that can be examined to provide information regarding the location, depth, and shape of the void. The microcomputer provides a means of real time processing to extract the information from the radar signal return and record the results. Theoretical modeling of signal returns from voids led to suitable techniques for locating and sizing voids beneath the pavement. Analysis and application of these techniques to radar measurements verified the theoretical predictions that radar can be used to determine the location, size, and shape of actual voids.

  12. Induction of Cell Activation Processes by Low Frequency Electromagnetic Fields

    Directory of Open Access Journals (Sweden)

    Myrtill Simkó

    2004-01-01

    Full Text Available Electromagnetic fields (EMF such as those from electric power transmission and distribution lines (50/60 Hz have been associated with increased risk of childhood leukemia, cancer of the nervous system, and lymphomas. Several in vitro studies on EMF effects were performed to clarify the existing controversies, define the risks, and determine the possible mechanisms of adverse effects. In some of these reports, the effects were related to other mechanisms of carcinogenesis. Modification in cell proliferation was observed after EMF exposure and a few reports on cytotoxic effects have also been published. This limited review gives an overview of the current results of scientific research regarding in vitro studies on the effects of power line frequency EMF, but also cell biological mechanisms and their potential involvement in genotoxicity and cytotoxicity are discussed. Cell cycle control and signal transduction processes are included to elucidate the biochemical background of possible interactions. Exposure to EMF has been also linked to the incidence of leukemia and other tumors in some epidemiological studies and is considered as “possibly carcinogenic to humans”, but there is no well-established biological mechanism that explains such a relation. Furthermore, EMF is also shown as a stimulus for immune relevant cells (e.g., macrophages to release free radicals. It is known that chronic activation of macrophages is associated with the onset of phagocytosis and leads to increased formation of reactive oxygen species, which themselves may cause DNA damage and are suggested to lead to carcinogenesis. To demonstrate a possible interaction between EMF and cellular systems, we present a mechanistic model describing cell activation as a major importance for cellular response.

  13. Electromagnetic-wave excitation in a large laboratory beam-plasma system

    Science.gov (United States)

    Whelan, D. A.; Stenzel, R. L.

    1981-01-01

    The mechanism by which unstable electrostatic waves of a beam-plasma system are converted into observed electromagnetic waves is of current interest in space physics and in tokamak fusion research. The process involved in the conversion of electrostatic to electromagnetic waves at the critical layer is well understood. However, the radiation from uniform plasmas cannot be explained on the basis of this process. In connection with certain difficulties, it has not yet been possible to establish the involved emission processes by means of experimental observations. In the considered investigation these difficulties are overcome by employing a large laboratory plasma in a parameter range suitable for detailed diagnostics. A finite-diameter electron beam is injected into a uniform quiescent afterglow plasma of dimensions large compared with electromagnetic wavelengths. The considered generation mechanism concerning the electromagnetic waves is conclusively confirmed by observing the temporal evolution of an instability

  14. Storage and retrieval of electromagnetic waves with orbital angular momentum via plasmon-induced transparency.

    Science.gov (United States)

    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.

  15. Characterization of Surface Electromagnetic Waves and Scattering on Infrared Metamaterial Absorbers

    CERN Document Server

    Chen, Wen-Chen; Liu, Xianliang; Tyler, Talmage; West, Kevin G; Bingham, Christopher M; Starr, Tatiana; Starr, Anthony F; Jokerst, Nan M; Padilla, Willie J

    2012-01-01

    We report, for the first time, a full experimental and computational investigation of all possible light matter interactions on the surface of an infrared metamaterial absorber (MMA). Two channels of energy dissipation - diffuse scattering and generation of surface electromagnetic waves - are quantified in terms of their impact on specular absorption. The diffuse scattering is found to play a negligible roll in the absorption process, at least for wavelengths greater than the periodicity of unit cell. In contrast, surface electromagnetic waves are found to be generated for transverse magnetic (TM) polarized light at the operational wavelength of the MMA, i.e. \\lambda_0, and shorter wavelengths. Our computational results indicate that the highly lossy surface electromagnetic wave generated at \\lambda_0 is responsible for the good angular dependence of absorption in TM polarization. Experimental results are supported by full wave three dimensional electromagnetic and eigenmode simulations.

  16. Electromagnetic fields induced by surface ring waves in the deep sea

    OpenAIRE

    Kozitskiy, S. B.

    2014-01-01

    The paper deals with electromagnetic effects associated with a radially symmetric system of progressive surface waves in the deep sea, induced by underwater oscillating sources or by dispersive decay of the initial localized perturbations of the sea surface.

  17. Stimulated Brillouin scattering of an electromagnetic wave in weakly magnetized plasma with variably charged dust particles

    Indian Academy of Sciences (India)

    Sourabh Bal; M Bose

    2009-10-01

    We have investigated analytically the stimulated Brillouin scattering (SBS) of an electromagnetic wave in non-dissipative weakly magnetized plasma in the presence of dust particles with variable charge.

  18. Reflection and Transmission of Plane Electromagnetic Waves by a Geologic Layer.

    Energy Technology Data Exchange (ETDEWEB)

    Aldridge, David F. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-04-01

    Electric field and magnetic field reflection and transmission responses generated by a plane wave normally incident onto a finite - thickness geologic layer are mathematically derived and numerically evaluated. A thin layer with enhanced electric current conductivity and/or magnetic permeability is a reasonable geophysical representation of a hydraulic fracture inject ed with a high - contrast proppant pack. Both theory and numerics indicate that backward - and forward - scattered electromagnetic wavefields are potentially observable in a field experiment, despite the extreme thinness of a fracture compared to a typical low - frequency electromagnetic wavelength. The First Born Approximation (FBA) representation of layer scattering, significant for inversion studies, is shown to be accurate for a thin layer with mild medium parameter (i.e., conductivity, permeability, and per mittivity) contrasts with the surrounding homogeneous wholespace. However, FBA scattering theory breaks down for thick layers and strong parameter contrasts. ACKNOWLEDGEMENTS Sandia National Laboratories is a multi - mission laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the US Department of Energy's National Nuclear Security Administration under contract DE - AC04 - 94AL85000. This research is conducted under the auspices of CRADA (Cooperative Research and Development Agreement) SC11/01780.00 between Carbo Ceramics Inc. and Sandia National Laboratories. The author acknowledges former Carbo R&D Vic e - President Mr. Chad Cannan and former SNL Geophysics Department manage r Ms. Amy Halloran for their interest i n and support of this work. Technical discussions with Project Manager and Principal Investigator Dr. Chester J. Weiss of the SNL Geophysics Department greatly benefited this work. Dr. Lewis C. Bartel, formerly with S NL and presently a consultant to Carbo Ceramics, provided many useful and intuitive insights, and

  19. Observations of Electrostatic and Electromagnetic Waves in the Earth's Magnetosphere.

    Science.gov (United States)

    Filbert, Paul Charles

    Using data from the University of Minnesota Plasma Wave Experiment aboard the IMP-6 (Explorer 43) satellite, three topics are addressed. The first concerns the wave lengths of certain electrostatic waves in the earth's magnetosphere. Using the fact that the X and Y dipole antennas on IMP-6 are of unequal length, the antenna response to electrostatic waves is calculated as a function of wavelength. This result is used to experimentally determine the wavelengths of Bernstein mode waves observed just beyond the plasmapause. These wavelengths are then used in conjunction with present theoretical models to determine the energy of the electrons driving these waves and a range of energies between (TURN) several tens to (TURN) several hundreds of electron volts is found. This procedure is also applied to Langmuir waves observed upstream of the earth's bow shock and the results are in good agreement with theoretical predictions. Second it is demonstrated that enhanced levels of the so-called continuum radiation are correlated with AE enhancements. In addition, a source region of continuum radiation is directly observed and movement of the source region is seen which is consistent with a cloud of electrons having been injected into the night side magnetosphere and undergoing gradient drifts in an eastward direction towards local dawn. This drift movement is then used to estimate the energy of the electrons which produce the observed continuum enhancement and a range between 10 kev to 50 kev is found. Spectral properties of the directly observed source are also presented, and indicate a high frequency spectral index of (TURN)f('-5.5). A new type of continuum radiation which correlates with TKR on a time scale of (TURN)1 minute is also observed and is found to have a source region distinct from that mentioned above. Third, a correlation between TKR and VLF auroral hiss has been observed for several high latitude passes of IMP-6 through the midnight auroral zone. This

  20. Interaction of Charged Particles with Ultra Strong Electromagnetic Waves in the Radiation Dominant Regime

    Science.gov (United States)

    Bulanov, S. V.; Esirkepov, T. Zh.; Koga, J.; Tajima, T.

    2004-10-01

    The plasma particle interaction with a relativistically intense electromagnetic wave under the conditions when the radiation reaction effects are dominant is considered. We analyze the radiation damping effects on the electron motion inside the circularly polarized planar wave and inside a subcycle crossed-field electromagnetic pulse. We consider the ion acceleration due to the radiation pressure action on a thin plasma slab. The results of 2D and 3D PIC simulations are presented.

  1. Neuronal cellular responses to extremely low frequency electromagnetic field exposure: implications regarding oxidative stress and neurodegeneration.

    Science.gov (United States)

    Reale, Marcella; Kamal, Mohammad A; Patruno, Antonia; Costantini, Erica; D'Angelo, Chiara; Pesce, Miko; Greig, Nigel H

    2014-01-01

    Neurodegenerative diseases comprise both hereditary and sporadic conditions characterized by an identifying progressive nervous system dysfunction and distinctive neuopathophysiology. The majority are of non-familial etiology and hence environmental factors and lifestyle play key roles in their pathogenesis. The extensive use of and ever increasing worldwide demand for electricity has stimulated societal and scientific interest on the environmental exposure to low frequency electromagnetic fields (EMFs) on human health. Epidemiological studies suggest a positive association between 50/60-Hz power transmission fields and leukemia or lymphoma development. Consequent to the association between EMFs and induction of oxidative stress, concerns relating to development of neurodegenerative diseases, such as Alzheimer disease (AD), have been voiced as the brain consumes the greatest fraction of oxygen and is particularly vulnerable to oxidative stress. Exposure to extremely low frequency (ELF)-EMFs are reported to alter animal behavior and modulate biological variables, including gene expression, regulation of cell survival, promotion of cellular differentiation, and changes in cerebral blood flow in aged AD transgenic mice. Alterations in inflammatory responses have also been reported, but how these actions impact human health remains unknown. We hence evaluated the effects of an electromagnetic wave (magnetic field intensity 1 mT; frequency, 50-Hz) on a well-characterized immortalized neuronal cell model, human SH-SY5Y cells. ELF-EMF exposure elevated the expession of NOS and O2(-), which were countered by compensatory changes in antioxidant catylase (CAT) activity and enzymatic kinetic parameters related to CYP-450 and CAT activity. Actions of ELF-EMFs on cytokine gene expression were additionally evaluated and found rapidly modified. Confronted with co-exposure to H2O2-induced oxidative stress, ELF-EMF proved not as well counteracted and resulted in a decline in CAT

  2. The influence of an electromagnetic field on the wave-current interaction

    CERN Document Server

    Rousseaux, Germain

    2010-01-01

    We study the propagation of surface waves on a current in the presence of an electromagnetic field. A horizontal (vertical) field strengthens (weakens) the counter-current which blocks the waves. We compute the phase space diagrams (blocking velocities versus period of the waves) with and without surface tension. Three new dimensionless numbers are introduced to compare the relative strengths of gravity, surface tension and field effects. This work shows the importance of an electromagnetic field in order to design wave-breakers or in microfluidics applications.

  3. Plasma-Maser Instability of the Electromagnetic Radiation In The Presence Of Electrostatic Drift Wave Turbulence in Inhomogeneous Plasma

    Directory of Open Access Journals (Sweden)

    Mahinder Singh

    2016-10-01

    Full Text Available The generation mechanism of the electromagnetic radiation in case of inhomogeneous plasma on the basis of plasma-maser interaction in presence of drift wave turbulence is studied. The drift wave turbulence is taken as the low-frequency mode field and is found to be strongly in phase relation with thermal particles and may transfer its wave energy nonlinearly through a modulated field of high-frequency extraordinary mode (X-mode wave. It has been found that amplification of X-mode wave is possible at the expense of drift wave turbulent energy. This type of high-frequency instability can leads to auroral kilometric radiation (AKR. The growth rate of the X-mode wave, in the form of AKR, has been calculated with the involvement of spatial density gradient parameter. This result may be particularly important for stability of various drift modes in magnetically confined plasma as well as for transport of momentum and energy in such inhomogeneous plasma

  4. Nonlinear Low Frequency Water Waves in a Cylindrical Shell

    Science.gov (United States)

    Peng, H. W.; Wang, D. J.; Lee, C. B.

    The experiment was carried out to study the low frequency surface waves due to the horizontal high frequency excitation. The feature of the phenomenon was that the big amplitude axisymmetric surface wave frequency was typically about 1/50 of the excitation frequency. The viscous effect of water was neglected as a first approximation in the earlier papers on this subject. In contrast, we found the viscosity was important to achieve the low frequency water wave with the cooperation of hundreds of "finger" waves. Photographs were taken with stroboscopic lighting and thereafter relevant quantitative results were obtained based on the measurements with Polytec Scanning Vibrometer PSV 400.

  5. Optimal Density Profile of the Plasma Layer Shielded by a Conducting Surface for the Absorption of Electromagnetic Waves

    Institute of Scientific and Technical Information of China (English)

    王舸; 曹金祥; 宋法伦

    2003-01-01

    Based on the Born approximation, we reduce the approximate analysis solution to the normal and oblique incident electromagnetic wave scattering from the weakly ionized plasma layer shielded by a conducting surface. The solution is closely related to the density profile of the plasma layer. Employing the self-consistent base function, we yield the optimal density profile for the nonuniform plasma layer with the frequencies of incident electromagnetic waves ranging from 4-10 GHz. Numerical studies illustrate the optimal density profile can "survive" wide ranges of the plasma parameters. Different from the validity condition for the Wenzell-Kramers-Brillouin-Jeffreys (WKBJ) approximation, the Born approximation is feasible even if the scale length is smaller than the wavelength.Therefore, the Born approximation is universal against the scattering problem from the weakly ionized plasma.

  6. Electromagnetic interference from radio frequency identification inducing potentially hazardous incidents in critical care medical equipment

    NARCIS (Netherlands)

    Togt, R. van der; Lieshout, E.J. van; Hensbroek, R.; Beinat, E.; Binnekade, J.M.; Bakker, P.J.M.

    2008-01-01

    Context: Health care applications of autoidentification technologies, such as radio frequency identification (RFID), have been proposed to improve patient safety and also the tracking and tracing of medical equipment. However, electromagnetic interference (EMI) by RFID on medical devices has never

  7. Electromagnetic Field Behavior in Dispersive Isotropic Negative Phase Velocity/Negative Refractive Index Guided Wave Structures Compatible with Millimeter-Wave Monolithic Integrated Circuits

    Directory of Open Access Journals (Sweden)

    Clifford M. Krowne

    2007-01-01

    Full Text Available A microstrip configuration has been loaded with a dispersive isotropic left-handed medium (LHM substrate and studied regarding its high frequency millimeter-wave behavior near 100 GHz. This has been accomplished using a full-wave integral-equation anisotropic Green's function code configured to run for isotropy. Never before seen electromagnetic field distributions are produced, unlike anything found in normal media devices, using this ab initio solver. These distributions are made in the cross-sectional dimension, with the field propagating in the perpendicular direction. It is discovered that the LHM distributions are so radically different from ordinary media used as a substrate that completely new electronic devices based upon the new physics become a real possibility. The distinctive dispersion diagram for the dispersive medium, consisting of unit cells with split ring resonator-rod combinations, is provided over the upper millimeter-wave frequency regime.

  8. Study on continuous electromagnetic surveys precisely controlled of frequency. Annual report on the field of advancing basic technology in 1996 fiscal year

    Energy Technology Data Exchange (ETDEWEB)

    Sanada, Yoshinori; Yamashita, Yoshihiro; Watanabe, Toshiki; Hasegawa, Takeshi; Yabuuchi, Satoshi

    1997-08-01

    This study aims at research and development of a system to control on high precision frequency of electromagnetic energy changing in tangential wave and to send it to underground continuously for long time, on geophysical investigation to analyze underground structure due to observation of underground response to it. By adopting this system, expansion of investigation depth, upgrading of analytical accuracy and miniaturization of investigation appliance were aimed. In 1996 fiscal year, in order to understand features of electromagnetic phenomenon over a wide range, a method to measure underground response to analyze its structure due to electromagnetic induction phenomenon by using comparative low frequency range of some tens Hz to some KHz at transmission frequency and a method to detect micro structure (for example crack, and so on) from transmittance and reflection phenomena by using comparatively high frequency range of some tens MHz to some GHz were investigated by using computer simulation. (G.K.)

  9. Averaged two-dimensional low-frequency wave spectrum of wind waves

    NARCIS (Netherlands)

    Kimura, A.

    1984-01-01

    This report deals with second order, two-dimensional low frequency waves induced by the non-linear interactions of the first order component waves in a two-dimensional short wave field. The convolution to calculate the averaged two-dimensional low frequency wave spectrum is developed. Any given two-

  10. Anisotropic effects of background fields on Born-Infeld electromagnetic waves

    OpenAIRE

    Aiello, Matias; Bengochea, Gabriel; Ferraro, Rafael

    2006-01-01

    We show exact solutions of Born-Infeld theory for electromagnetic plane waves propagating in the presence of static background fields. The non-linear character of Born-Infeld equations generates an interaction between background and 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...

  11. Ranolazine reduces atrial fibrillatory wave frequency.

    Science.gov (United States)

    Black-Maier, Eric W; Pokorney, Sean D; Barnett, Adam S; Liu, Peter; Shrader, Peter; Ng, Jason; Goldberger, Jeffrey J; Zareba, Wojiech; Daubert, James P; Grant, Augustus O; Piccini, Jonathan P

    2017-07-01

    Antiarrhythmic medications for the treatment of atrial fibrillation (AF) have limited efficacy and rare but potentially life-threatening side effects. Ranolazine is an antianginal agent that may have antiarrhythmic activity in AF. Using the Duke Enterprise Data Unified Content Explorer database, we analysed a cohort of AF patients on ranolazine. Patients served as their own historic control. Electrocardiograms (ECGs) were analysed before and after ranolazine initiation to determine the effect of ranolazine on dominant frequency (DF), f-wave amplitude, and organizational index (OI). We identified 15 patients with ECGs in AF before and after ranolazine. Ranolazine was associated with lower DF by an average of 10% (5.10 ± 0.74 vs. 5.79 ± 0.96 Hz, P = 0.04) but not with changes in OI (0.47 ± 0.11 vs. 0.50 ± 0.12, P = 0.71) or amplitude (0.47 ± 0.43 vs. 0.41 ± 0.40 mV, P = 0.82). Ranolazine was also associated with lower DF in patients (n = 10) not on concomitant antiarrhythmic therapy (5.25 ± 0.78 vs. 6.03 ± 0.79 Hz, P = 0.04). Ranolazine is associated with lower AF DF but no change in OI or fibrillatory wave amplitude. Prospective trials are needed to evaluate ranolazine's potential as a novel antiarrhythmic drug for AF.

  12. Electromagnetic Wave Shielding Effectiveness Based on Carbon Microcoil-Polyurethane Composites

    Directory of Open Access Journals (Sweden)

    Gi-Hwan Kang

    2014-01-01

    Full Text Available Carbon microcoils (CMCs were deposited onto Al2O3 substrates using C2H2/H2 as source gases and SF6 as an incorporated additive gas in a thermal chemical vapor deposition system. CMC-polyurethane (PU composites were obtained by dispersing the CMCs in the PU with a dimethylformamide additive. The electromagnetic wave shielding properties of the CMC-PU composites were examined in the frequency range of 0.25–1.5 GHz. The shielding effectiveness (SE of the CMCs-PU systematically increases with increasing the content of CMCs and/or the layer thickness. Based on these results, the main SE mechanism for this work was suggested and discussed.

  13. Temporal Skewness of Electromagnetic Pulsed Waves Propagating Through Random Media with Embedded Irregularity Slab

    Institute of Scientific and Technical Information of China (English)

    许正文; 吴健; 霍文平; 吴振森

    2003-01-01

    Electromagnetic pulsed waves can be distorted in the propagation through random media, and their energy dis tributions change along the leading and trailing edge of the waveform, which can be presented by the temporal skewness. The skewness presents asymmetry and is treated by the third-order temporal moment, in which an analytic solution for the two-frequency mutual coherence function is obtained recently. Then, transionospheric pulses are discussed in details. Both theoretical analysis and numerical computation indicate that the contri butions from scattering and dispersion of irregularities dominate over those of background, so the latter can be neglected in most cases. Also, the temporal skewness of a transionospheric pulse is negative and energy is shifted to the leading edge.

  14. Capturing the electromagnetic counterparts of binary neutron star mergers through low latency gravitational wave triggers

    CERN Document Server

    Chu, Q; Rowlinson, A; Gao, H; Zhang, B; Tingay, S J; Boer, M; Wen, L

    2015-01-01

    We investigate the prospects for joint low-latency gravitational wave (GW) detection and prompt electromagnetic (EM) follow-up observations of coalescing binary neutron stars (BNSs). Assuming BNS mergers are associated with short duration gamma ray bursts (SGRBs), we evaluate if rapid EM follow-ups can capture the prompt emission, early engine activity or reveal any potential by-products such as magnetars or fast radio bursts. To examine the expected performance of low-latency search pipelines we simulate a population of coalescing BNSs using realistic distributions of source parameters to estimate the detectability and localisation efficiency at different times before merger. To determine what EM observations can be achieved, we consider a selection of facilities with GW follow-up agreements in place, from low-frequency radio to high energy $\\gamma$-ray; we assess the performance of each using observational SGRB flux data corrected to the range of the advanced GW interferometric detectors LIGO and Virgo. We ...

  15. Reflection of plane electromagnetic waves from the surface of a perfect conductor moving in an arbitrary direction

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The reflection of plane electromagnetic waves (TE wave and TM wave) from a perfect conductor which moves in an arbitrary direction is investigated. Based on Maxwell's equations and the boundary conditions for moving boundary, the relation between the field vectors of reflected and incident waves, and the reflection coefficient are derived. The energy balance between incident and reflected waves, the force exerted by electromagnetic waves to the moving conductor are also discussed and some new conclusions are suggested for notice.

  16. Tunable electromagnetically induced transparency at terahertz frequencies in coupled graphene metamaterial

    Science.gov (United States)

    Ding, Guo-Wen; Liu, Shao-Bin; Zhang, Hai-Feng; Kong, Xiang-Kun; Li, Hai-Ming; Li, Bing-Xiang; Liu, Si-Yuan; Li, Hai

    2015-11-01

    A graphene-based metamaterial with tunable electromagnetically induced transparency (EIT)-like transmission is numerically studied in this paper. The proposed structure consists of a graphene layer composed of coupled cut-wire pairs printed on a substrate. The simulation confirms that an EIT-like transparency window can be observed due to indirect coupling in a terahertz frequency range. More importantly, the peak frequency of the transmission window can be dynamically controlled over a broad frequency range by varying the Fermi energy levels of the graphene layer through controlling the electrostatic gating. The proposed metamaterial structure offers an additional opportunity to design novel applications such as switches or modulators. Project supported by the National Natural Science Foundation of China (Grant No. 61307052), the Youth Funding for Science & Technology Innovation in Nanjing University of Aeronautics and Astronautics, China (Grant No. NS2014039), the Chinese Specialized Research Fund for the Doctoral Program of Higher Education (Grant No. 20123218110017), the Innovation Program for Graduate Education of Jiangsu Province, China (Grant Nos. KYLX_0272, CXZZ13_0166, and CXLX13_155), the Open Research Program in National State Key Laboratory of Millimeter Waves of China (Grant No. K201609), and the Fundamental Research Funds for the Central Universities of China (Grant No. kfjj20150407).

  17. Preparation of semisolid AlSi7Mg alloy slurry through weak traveling-wave electromagnetic stirring

    Institute of Scientific and Technical Information of China (English)

    Zhen-duo Zhao; Wei-min Mao; Sha Li; Rong-mao Zhong

    2009-01-01

    The semisolid AlSi7Mg alloy slurry with large capacity was prepared by low superheat pouring and week traveling-wave electromagnetic stirring. The effects of electromagnetic stirring power and frequency on the shape and distribution of primary α-Al grains in the AlSi7Mg alloy slurry were discussed. The experimental results show that the AlSi7Mg alloy slurry with fine and spherical primary α-Al grains distributed homogeneously can be obtained. Under the condition of low superheat pouring and week traveling-wave electromagnetic stirring, when the pouring temperature is 630°C, raising the stirring power or frequency appropriately can gain a better shape of primary α-Al grains; but if the stirring power or frequency is increased to a certain value (1.72 kW or 10Hz), the shape of primary α-Al grains cannot be obviously improved and spherical primary α-Al grains distributed homogeneously can be still obtained.

  18. THE DAMAGING EFFECTS OF EXPOSURE TO EXTREMELY LOW FREQUENCES OF ELECTROMAGNETIC FIELDS

    OpenAIRE

    Dejan Petković; Dejan Krstić; Dušan Sokolović; Boris Đinđić; Jovica Jovanović; Petar Babović

    2010-01-01

    In both living and working environment, apart from the ever present Earth's atmospheric and magnetic fields, very often there is an existing very low- frequency electromagnetic field emitted by energy plants, home, radio and TV appliances, public transport vehicles and video terminals. Low-frequency electromagnetic fields (30-300 Hz) are also present in the vicinity of high-voltage transmission lines, high and middle voltage conductors, sub-stations and industry. A large number of people who ...

  19. Effects of chronic exposure to electromagnetic waves on the auditory system.

    Science.gov (United States)

    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).

  20. Bichromatic field generation from double-four-wave mixing in a double-electromagnetically induced transparency system

    CERN Document Server

    Liu, Yang; Ding, Dongsheng; Shi, Baosen; Guo, Guangcan

    2012-01-01

    We demonstrate the double electromagnetically induced transparency (double-EIT) and double four-wave mixing (double-FWM) based on a new scheme of non-degenerate four-wave mixing (FWM) involving five levels of a cold 85Rb atomic ensemble, in which the double-EIT windows are used to transmit the probe field and enhance the third-order nonlinear susceptibility. The phase-matching conditions for both four-wave mixings could be satisfied simultaneously. The frequency of one component of the generated bichromatic field is less than the other by the ground-state hyperfine splitting (3GHz). This specially designed experimental scheme for simultaneously generating different nonlinear wave-mixing processes is expected to find applications in quantum information processing and cross phase modulation. Our results agree well with the theoretical simulation.

  1. Low Frequency Scattering Resonance Wave in Strong Heterogeneity

    CERN Document Server

    Liu, Yinbin

    2015-01-01

    Multiple scattering of wave in strong heterogeneity can cause resonance-like wave phenomenon where signal exhibits low frequency, high intensity, and slowly propagating velocity. For example, long period event in volcanic seismology and surface plasmon wave and quantum Hall effect in wave-particle interactions. Collective behaviour in a many-body system is usually thought to be the source for generating the anomaly. However, the detail physical mechanism is not fully understood. Here I show by wave field modeling for microscopic bubble cloud model and 1D heterogeneity that the anomaly is related to low frequency scattering resonance happened in transient regime. This low frequency resonance is a kind of wave coherent scattering enhancement phenomenon in strongly-scattered small-scale heterogeneity. Its resonance frequency is inversely proportional to heterogeneous scale and contrast and will further shift toward lower frequency with random heterogeneous scale and velocity fluctuations. Low frequency scatterin...

  2. Impact of Low Frequency Electromagnetic Field Exposure on the Candida Albicans

    Science.gov (United States)

    Malíková, Ivona; Janoušek, Ladislav; Fantova, Vladyslava; Jíra, Jaroslav; Kříha, Vítĕzslav

    2015-03-01

    Effect of low frequency electromagnetic field on growth of selected microorganism is studied in the article. The diploid fungus that grows both as yeast and filamentous cell was chosen for this research. The theory of ion parametric resonance was taken as the base for studying the influence of electromagnetic field on biological structures. We tested the hypothesis, whether it is possible to observe the change in growth properties of Candida albicans with an AC electromagnetic field tuned to resonance with calcium ions cyclotron frequency.

  3. Elastic metamaterials for tuning circular polarization of electromagnetic waves.

    Science.gov (United States)

    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.

  4. Elastic metamaterials for tuning circular polarization of electromagnetic waves

    Science.gov (United States)

    Zárate, Yair; Babaee, Sahab; Kang, Sung H.; Neshev, Dragomir N.; Shadrivov, Ilya V.; Bertoldi, Katia; Powell, David A.

    2016-01-01

    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. PMID:27320212

  5. Microscale capillary wave turbulence excited by high frequency vibration.

    Science.gov (United States)

    Blamey, Jeremy; Yeo, Leslie Y; Friend, James R

    2013-03-19

    Low frequency (O(10 Hz-10 kHz)) vibration excitation of capillary waves has been extensively studied for nearly two centuries. Such waves appear at the excitation frequency or at rational multiples of the excitation frequency through nonlinear coupling as a result of the finite displacement of the wave, most often at one-half the excitation frequency in so-called Faraday waves and twice this frequency in superharmonic waves. Less understood, however, are the dynamics of capillary waves driven by high-frequency vibration (>O(100 kHz)) and small interface length scales, an arrangement ideal for a broad variety of applications, from nebulizers for pulmonary drug delivery to complex nanoparticle synthesis. In the few studies conducted to date, a marked departure from the predictions of classical Faraday wave theory has been shown, with the appearance of broadband capillary wave generation from 100 Hz to the excitation frequency and beyond, without a clear explanation. We show that weak wave turbulence is the dominant mechanism in the behavior of the system, as evident from wave height frequency spectra that closely follow the Rayleigh-Jeans spectral response η ≈ ω(-17/12) as a consequence of a period-halving, weakly turbulent cascade that appears within a 1 mm water drop whether driven by thickness-mode or surface acoustic Rayleigh wave excitation. However, such a cascade is one-way, from low to high frequencies. The mechanism of exciting the cascade with high-frequency acoustic waves is an acoustic streaming-driven turbulent jet in the fluid bulk, driving the fundamental capillary wave resonance through the well-known coupling between bulk flow and surface waves. Unlike capillary waves, turbulent acoustic streaming can exhibit subharmonic cascades from high to low frequencies; here it appears from the excitation frequency all the way to the fundamental modes of the capillary wave at some four orders of magnitude in frequency less than the excitation frequency

  6. Arrival time differences between gravitational waves and electromagnetic signals due to gravitational lensing

    CERN Document Server

    Takahashi, Ryuichi

    2016-01-01

    In this study, we demonstrate that general relativity predicts arrival time differences between gravitational wave (GW) and electromagnetic (EM) signals caused by the wave effects in gravitational lensing. The GW signals can arrive $earlier$ than the EM signals in some cases if the GW/EM signals have passed through a lens, even if both signals were emitted simultaneously by a source. GW wavelengths are much larger than EM wavelengths; therefore, the propagation of the GWs does not follow the laws of geometrical optics, including the Shapiro time delay, if the lens mass is less than approximately $10^5 {\\rm M}_\\odot (f/{\\rm Hz})^{-1}$, where $f$ is the GW frequency. The arrival time difference can reach $\\sim 0.1 \\, {\\rm s} \\, (f/{\\rm Hz})^{-1}$; therefore, it is more prominent for lower GW frequencies. Gravitational lensing imprints a characteristic modulation on a chirp waveform; therefore, we can deduce whether a measured arrival time lag arises from intrinsic source properties or gravitational lensing. Det...

  7. Preparation and electromagnetic wave absorption properties of Sm2O3/α-Fe/Sm2Fe17Nx composites

    Science.gov (United States)

    Ye, Jinwen; Liu, Ying; Zhang, Jiao; Chen, Xianfu; Yao, Mingying

    2013-06-01

    Sm2O3/α-Fe/Sm2Fe17Nx composites were prepared in situ by hydrogenation-disproportionation-oxygen-desorption-recombination and nitrogen process, and their electromagnetic wave absorption properties were measured in the frequency range of 0.5-18 GHz. The result showed that saturation magnetization and coercivity of as-prepared powder with 25.3 wt% Sm2O3, 64.4 wt% α-Fe and 10.3 wt% Sm2Fe17N3 were 134.57 emu/g and 654.5 G, respectively. The dielectric constant of composites was low over the frequency range of 0.5-18 GHz, and their resonance frequencies were at a high frequency range. The resin composite of Sm2O3/α-Fe/Sm2Fe17N3 exhibited effective electromagnetic wave absorption (RL≤20 dB) in a frequency range 3-9 GHz, for absorber thickness ranging from 3 to 8 mm, respectively. A minimum reflection loss of -53 dB from the samples was observed at 7 GHz with an absorber thickness of 3.59 mm.

  8. The relation between the specific absorption rate and electromagnetic field intensity for heterogeneous exposure conditions at mobile communications frequencies.

    Science.gov (United States)

    Neubauer, Georg; Preiner, Patrick; Cecil, Stefan; Mitrevski, Niki; Gonter, Johannes; Garn, Heinrich

    2009-12-01

    The relation between the incident electromagnetic field strength and both the whole-body and the local specific absorption rate (SAR) was investigated for typical heterogeneous exposure scenarios for frequencies relevant for mobile communication. The results were compared to results from plane wave exposure. Heterogeneous exposure arises from multiple path propagation of the electromagnetic waves to the location of interest. It is shown that plane wave exposure does not represent worst-case exposure conditions. When the electric field strength arising at plane wave exposure is compared to the electric field strength averaged over the volume of the human body occurring during multipath exposure, 12% of all heterogeneous cases examined represent worse exposure conditions than plane wave exposure for whole-body exposure at 946 MHz, 15% at 1840 MHz, and 22% at 2140 MHz. The deviation between plane wave and heterogeneous whole-body SAR ranges from -54% to 54%. For partial-body SAR averaged over 10 g of tissue, a range from -93% to 209% was found when comparing multiple wave exposure to single incoming plane waves. The investigations performed using the Visible Human as phantom showed that the basic restrictions are met as long as the reference levels are not exceeded. However, this must not be necessarily the case when different phantoms are used to perform similar investigations because recent studies demonstrated that reference levels might not be conservative when phantoms of children are used. Therefore, the results of this work indicate the need to extend the investigations to numerical simulations with additional human phantoms representing parts of the human population having different anatomy and morphology compared to the phantom used within the frame of this project. This also applies to phantoms of children.

  9. Calcium signalling in human neutrophil cell lines is not affected by low-frequency electromagnetic fields.

    Science.gov (United States)

    Golbach, Lieke A; Philippi, John G M; Cuppen, Jan J M; Savelkoul, Huub F J; Verburg-van Kemenade, B M Lidy

    2015-09-01

    We are increasingly exposed to low-frequency electromagnetic fields (LF EMFs) by electrical devices and power lines, but if and how these fields interact with living cells remains a matter of debate. This study aimed to investigate the potential effect of LF EMF exposure on calcium signalling in neutrophils. In neutrophilic granulocytes, activation of G-protein coupled receptors leads to efflux of calcium from calcium stores and influx of extracellular calcium via specialised calcium channels. The cytoplasmic rise of calcium induces cytoskeleton rearrangements, modified gene expression patterns, and cell migration. If LF EMF modulates intracellular calcium signalling, this will influence cellular behaviour and may eventually lead to health problems. We found that calcium mobilisation upon chemotactic stimulation was not altered after a short 30 min or long-term LF EMF exposure in human neutrophil-like cell lines HL-60 or PLB-985. Neither of the two investigated wave forms (Immunent and 50 Hz sine wave) at three magnetic flux densities (5 μT, 300 μT, and 500 μT) altered calcium signalling in vitro. Gene-expression patterns of calcium-signalling related genes also did not show any significant changes after exposure. Furthermore, analysis of the phenotypical appearance of microvilli by scanning electron microscopy revealed no alterations induced by LF EMF exposure. The findings above indicate that exposure to 50 Hz sinusoidal or Immunent LF EMF will not affect calcium signalling in neutrophils in vitro.

  10. The applicability range of different forms of the radiation friction force in the ultrarelativistic electron interaction with electromagnetic wave (exact solutions)

    Science.gov (United States)

    Bulanov, S. S.; Esirkepov, T. Zh; Kando, M.; Koga, J. K.; Bulanov, S. V.

    2013-02-01

    When the effects of radiation reaction dominate the interaction of electrons with intense laser pulses, the electron dynamics changes qualitatively. The adequate theoretical description of this regime becomes crucially important with the use of the radiation friction force either in the Lorentz-Abraham-Dirac form, which possess unphysical runaway solutions, or in the Landau-Lifshitz form, which is a perturbation valid for relatively low electromagnetic wave amplitude. The goal of the present paper is to find the limits of the Landau-Lifshitz radiation force applicability in terms of the electromagnetic wave amplitude and frequency.

  11. The Relativistic Transformation for an Electromagnetic Plane Wave with General Time Dependence

    Science.gov (United States)

    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…

  12. Teaching the Common Aspects in Mechanical, Electromagnetic and Quantum Waves at Interfaces and Waveguides

    Science.gov (United States)

    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…

  13. Teaching the Common Aspects in Mechanical, Electromagnetic and Quantum Waves at Interfaces and Waveguides

    Science.gov (United States)

    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…

  14. geometric optics and WKB method for electromagnetic wave propagation in an inhomogeneous plasma near cutoff

    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 ne(r), which will modify the wave propagation in the direction of the gradient rne(r).

  15. Sandwich-Like Graphite-Fullerene Composites with Enhanced Electromagnetic Wave Absorption

    Science.gov (United States)

    Zhong, Jiachun; Jia, Kun; Pu, Zejun; Liu, Xiaobo

    2016-11-01

    Sandwich-like graphite-fullerene composites have been prepared via a simple solution mixing/evaporation method. The complex relative permittivity and permeability of the graphite-fullerene composites in the frequency range from 0.5 GHz to 18 GHz were measured using a vector network analyzer with the reflection/transmission technique. Additionally, the microwave reflection loss of the composites was calculated using the obtained complex microwave electromagnetic parameters. It was found that the microwave loss peaks in the Ku band were dependent on the concentration of fullerene nanoparticles in the composites. Maximum reflection loss of -30 dB was observed between 2 GHz and 8 GHz when the graphite composites were doped with 1 wt.% fullerene. This absorption loss dropped (-24 dB) when the composite contained 3 wt.% fullerene. In addition, the electrical properties of the graphite were independent of the presence of fullerene in the composites. The tunable microwave reflection loss indicates that these graphite-fullerene composites show promise as wideband electromagnetic wave absorption materials.

  16. Reduced Graphene Oxide Functionalized with Cobalt Ferrite Nanocomposites for Enhanced Efficient and Lightweight Electromagnetic Wave Absorption

    Science.gov (United States)

    Ding, Yi; Liao, Qingliang; Liu, Shuo; Guo, Huijing; Sun, Yihui; Zhang, Guangjie; Zhang, Yue

    2016-01-01

    In this paper, reduced graphene oxide functionalized with cobalt ferrite nanocomposites (CoFe@rGO) as a novel type of electromagnetic wave (EW) absorbing materials was successfully prepared by a three-step chemical method including hydrothermal synthesis, annealing process and mixing with paraffin. The effect of the sample thickness and the amount of paraffin on the EW absorption properties of the composites was studied, revealing that the absorption peaks shifted toward the low frequency regions with the increasing thickness while other conditions had little or no effect. It is found that the CoFe@rGO enhanced both dielectric losses and magnetic losses and had the best EW absorption properties and the wide wavelength coverage of the hole Ku-Band when adding only 5wt% composites to paraffin. Therefore, CoFe@rGO could be used as an efficient and lightweight EW absorber. Compared with the research into traditional absorbing materials, this figures of merit are typically of the same order of magnitude, but given the lightweight nature of the material and the high level of compatibility with mass production standards, making use of CoFe@rGO as an electromagnetic absorber material shows great potential for real product applications. PMID:27587001

  17. Radio-Frequency Characteristics of a Printed Rectangular Helix Slow-Wave Structure

    Institute of Scientific and Technical Information of China (English)

    FU Cheng-Fang; WEI Yan-Yu; WANG Wen-Xiang; GONG Yu-Bin

    2008-01-01

    A new type of printed rectangular he/ix slow-wave structure (SWS) is investigated using the field-matching method and the electromagnetic integral equations at the boundaries. The radio-frequency characteristics including the dispersion equation and the coupling impedance for transverse antisymmetric (odd) modes of this structure are analysed. The numerical results agree well with the results obtained by the EM simulation software HFSS. It is shown that the dispersion of the rectangular helix circuit is weakened, the phase velocity is reduced after filling the dielectric materials in the rectangular helix SWS. As a planar slow-wave structure, this structure has potential applications in compact TWTs.

  18. Berreman approach to electromagnetic wave and beam propagation in anisotropic metamaterials

    Science.gov (United States)

    Gnawali, Rudra; Banerjee, Partha

    2016-09-01

    The Berreman matrix method is used to analyze the polarization and propagation of electromagnetic waves and beams in anisotropic metamaterials. The metamaterial, comprising a multilayer structure of alternating metal and dielectric layers, is modeled as an effective anisotropic medium. The Maxwell's equations for electromagnetic propagation are then represented as a set of coupled differential equations using the Berreman matrix. These coupled equations are then solved analytically and cross checked numerically using MATLAB® for plane wave propagation. The analysis can be extended to Gaussian beam propagation through such anisotropic metamaterials using the angular plane wave spectral approach.

  19. Group delay of electromagnetic pulses through multilayer dielectric mirrors combined with gravitational wave.

    Science.gov (United States)

    Liu, J T; Wu, X; Liu, N H; Li, J; Su, F H

    2013-07-01

    Group delay of electromagnetic pulses through multilayer dielectric mirrors (MDM) combined with gravitational wave (GW) is investigated. Unlike in traditional quantum tunneling, the group delay of a transmitted wave packet irradiated by a GW increases linearly with MDM length. This peculiar tunneling effect can be attributed to electromagnetic wave leakage in a time-dependent photonic bandgap caused by the GW. In particular, we find that the group delay of the tunneling photons is sensitive to GW. Our study provides insight into the nature of the quantum tunnelling as well as a novel process by which to detect the GW.

  20. Effect of low frequency electromagnetic field on microstructures and macrosegregation of horizontal direct chill casting aluminum alloy

    Institute of Scientific and Technical Information of China (English)

    赵志浩; 崔建忠; 董杰; 张海涛; 张北江

    2004-01-01

    The influences of low frequency electromagnetic field on cast surface, microstructures and macrosegregation in horizontal direct chill(HDC) casting process were investigated experimentally. The cast surfaces, microstructures and macrosegregation of the ingots manufactured by conventional HDC and low frequency electromagnetic HDC casting were compared. The results show that low frequency electromagnetic field significantly improves the surface quality, refines the microstructures and reduces macrosegregation. Further more, increasing electromagnetic intensity or decreasing frequency is beneficial to the improvement. In the range of ampere-turns and frequency employed in the experiments, the optimum ampere-turns is found to be 10 000 A · turn and the frequency to be 30 Hz.

  1. Simulation of TunneLadder traveling-wave tube cold-test characteristics: Implementation of the three-dimensional, electromagnetic circuit analysis code micro-SOS

    Science.gov (United States)

    Kory, Carol L.; Wilson, Jeffrey D.

    1993-01-01

    The three-dimensional, electromagnetic circuit analysis code, Micro-SOS, can be used to reduce expensive time-consuming experimental 'cold-testing' of traveling-wave tube (TWT) circuits. The frequency-phase dispersion characteristics and beam interaction impedance of a TunneLadder traveling-wave tube slow-wave structure were simulated using the code. When reasonable dimensional adjustments are made, computer results agree closely with experimental data. Modifications to the circuit geometry that would make the TunneLadder TWT easier to fabricate for higher frequency operation are explored.

  2. Cone structure and focusing of VLF and LF electromagnetic waves at high altitudes in the ionosphere

    Science.gov (United States)

    Alpert, Ya. L.; Green, J. L.

    1994-01-01

    The frequency and angle dependencies of the electric field radiated by an electric dipole E = E(sub 0) cos omega(t) are studied through numerical calculations of absolute value of E in the VLF and LF frequency bands where F is less than or equal 0.02 to 0.05 f(sub b) in a model ionosphere over an altitude region of 800-6000 km where the wave frequency and electron gyrofrequency varies between F approximately 4-500 kHz and f(sub b) is approximately equal (1.1 to 0.2) MHz respectively. It is found that the amplitudes of the electric field have large maxima in four regions: close to the direction of the Earth magnetic field line B(sub 0) (it is called the axis field E(sub 0), in the Storey E(sub St), reversed Storey E(sub RevSt), and resonance E(sub Res) cones. The maximal values of E(sub 0), E(sub Res), and E(sub RevSt) are the most pronounced close to the lower hybrid frequency, F approximately F(sub L). The flux of the electric field is concentrated in very narrow regions, with the apex angles of the cones Delta-B is approximately (0.1-1) deg. The enhancement and focusing of the electric field increases with altitude starting at Z greater than 800 km. At Z greater than or equal to 1000 up to 6000 km, the relative value of absolute value of E, in comparison with its value at Z = 800 km is about (10(exp 2) to 10(exp 4)) times larger. Thus the flux of VLF and LF electromagnetic waves generated at high altitudes in the Earth's ionosphere are trapped into very narrow conical beams similar to laser beams.

  3. Cone structure and focusing of VLF and LF electromagnetic waves at high altitudes in the ionosphere

    Science.gov (United States)

    Alpert, Ya. L.; Green, J. L.

    1994-01-01

    The frequency and angle dependencies of the electric field radiated by an electric dipole E = E(sub 0) cos omega(t) are studied through numerical calculations of absolute value of E in the VLF and LF frequency bands where F is less than or equal 0.02 to 0.05 f(sub b) in a model ionosphere over an altitude region of 800-6000 km where the wave frequency and electron gyrofrequency varies between F approximately 4-500 kHz and f(sub b) is approximately equal (1.1 to 0.2) MHz respectively. It is found that the amplitudes of the electric field have large maxima in four regions: close to the direction of the Earth magnetic field line B(sub 0) (it is called the axis field E(sub 0), in the Storey E(sub St), reversed Storey E(sub RevSt), and resonance E(sub Res) cones. The maximal values of E(sub 0), E(sub Res), and E(sub RevSt) are the most pronounced close to the lower hybrid frequency, F approximately F(sub L). The flux of the electric field is concentrated in very narrow regions, with the apex angles of the cones Delta-B is approximately (0.1-1) deg. The enhancement and focusing of the electric field increases with altitude starting at Z greater than 800 km. At Z greater than or equal to 1000 up to 6000 km, the relative value of absolute value of E, in comparison with its value at Z = 800 km is about (10(exp 2) to 10(exp 4)) times larger. Thus the flux of VLF and LF electromagnetic waves generated at high altitudes in the Earth's ionosphere are trapped into very narrow conical beams similar to laser beams.

  4. Terahertz emission and electromagnetic waves in single crystal Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8} structures

    Energy Technology Data Exchange (ETDEWEB)

    Wieland, Raphael; Rudau, Fabian; Gross, Boris; Judd, Thomas; Koelle, Dieter; Kleiner, Reinhold [Physikalisches Institut and Center for Collective Quantum Phenomena in LISA" +, Universitaet Tuebingen, Tuebingen (Germany); Kinev, Nickolay; Koshelets, Valery [Kotel' nikov Institute of Radio Engineering and Electronics, Moscow (Russian Federation); Tsujimoto, Manabu [Kyoto University, Kyoto (Japan); Ji, Min; Huang, Ya; Zhou, Xianjing; An, Deyue; Wang, Huabing [National Institute for Materials Science, Tsukuba (Japan); Research Institute of Superconductor Electronics, Nanjing University, Nanjing (China); Wu, Peihang [Research Institute of Superconductor Electronics, Nanjing University, Nanjing (China); Hatano, Takeshi [National Institute for Materials Science, Tsukuba (Japan)

    2015-07-01

    Josephson Junctions (JJs) offer a natural way to convert a dc voltage into high-frequency electromagnetic radiation. In the high-Tc superconductor Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8} (BSCCO), JJs form intrinsically, allowing to fabricate stacks of hundreds of junctions easily. Emission can occur at relatively low bias currents but also at larger input power with frequencies from 0.4 to 1 THz. At high bias, a hot spot forms, affecting both the intensity and the linewidth of the radiation. BSCCO mesas are believed to work as a cavity for electromagnetic standing waves, synchronizing all the junctions in the stack. We investigated THz emission and hotspot formation using a combination of transport measurements, electromagnetic wave detection via a superconducting receiver and low temperature scanning laser microscopy.

  5. In vitro testing of cellular response to ultra high frequency electromagnetic field radiation.

    Science.gov (United States)

    Pavicic, Ivan; Trosic, Ivancica

    2008-08-01

    The aim of this study was to evaluate whether low-level, ultra high frequency (UHF) irradiation of 935 MHz influences the cell structure and growth of V79 cells. UHF field was generated inside a Gigahertz Transversal Electromagnetic Mode cell (GTEM-cell) with a Hewlett-Packard signal generator. The electric field strength was 8.2+/-0.3 V/cm and the average specific absorption rate (SAR) was calculated to be 0.12 W/kg. Cell samples were cultivated in a humidified atmosphere at 37 degrees C with 5% CO2. Prepared cell samples were exposed to a 935 MHz continuous wave frequency field for 1, 2, and 3 h. The structure of microtubule proteins has been determined using the immunocytochemical method. Cell growth was determined by cell counts for each hour of exposure during five post-exposure days. Negative- and positive-cell controls were included into the experimental procedure. In comparison with control cells, the microtubule structure clearly altered after 3h of irradiation (pgrowth was noted in cells exposed for 3h three days after irradiation (pcell growth.

  6. Electromagnetic Low-Frequency Dipolar Excitation of Two Metal Spheres in a Conductive Medium

    Directory of Open Access Journals (Sweden)

    Panayiotis Vafeas

    2012-01-01

    Full Text Available This work concerns the low-frequency interaction of a time-harmonic magnetic dipole, arbitrarily orientated in the three-dimensional space, with two perfectly conducting spheres embedded within a homogeneous conductive medium. In such physical applications, where two bodies are placed near one another, the 3D bispherical geometry fits perfectly. Considering two solid impenetrable (metallic obstacles, excited by a magnetic dipole, the scattering boundary value problem is attacked via rigorous low-frequency expansions in terms of integral powers (ikn, where n≥0, k being the complex wave number of the exterior medium, for the incident, scattered, and total non-axisymmetric electric and magnetic fields. We deal with the static (n=0 and the dynamic (n=1,2,3 terms of the fields, while for n≥4 the contribution has minor significance. The calculation of the exact solutions, satisfying Laplace’s and Poisson’s differential equations, leads to infinite linear systems, solved approximately within any order of accuracy through a cut-off procedure and via numerical implementation. Thus, we obtain the electromagnetic fields in an analytically compact fashion as infinite series expansions of bispherical eigenfunctions. A simulation is developed in order to investigate the effect of the radii ratio, the relative position of the spheres, and the position of the dipole on the real and imaginary parts of the calculated scattered magnetic field.

  7. New low-frequency electromagnetic modes associated with neutral dynamics in partially ionised plasma

    Directory of Open Access Journals (Sweden)

    A. A. Shaikh

    2013-05-01

    Full Text Available We have investigated the low frequency electromagnetic (EM modes in inhomogeneous, magnetised partially ionised plasma by incorporating neutral dynamics. We have derived a general EM dispersion relation by using a two-fluids magnetohydrodynamics (MHD model. Our analysis shows that the neutral dynamics is playing an extremely important role in the physics of magnetised partially ionised plasma by giving rise to new kind of EM modes. We found (1 the new instability is linked with compressibility of neutral particles, the collision between neutral and charged species and the relative streaming in hot/cold, inhomogeneous, magnetised partially ionised plasma, (2 and that neutral dynamics is responsible for the modified (complex inertial effect on magnetic field lines. Its consequences on the propagation characteristics of Alfvén wave and cyclotron frequency are discussed. Furthermore, a new mode similar to the Langmuir mode is reported. Finally, we discuss our results, for limiting cases, that may be appropriate for applications to space plasma environments including probable mechanism of escaping H+ and O− from the Martian atmosphere.

  8. Parametric excitation of electromagnetic fields by two pump waves

    Energy Technology Data Exchange (ETDEWEB)

    Brodin, G.; Lundberg, J.; Stenflo, L. (Umeaa Univ. (Sweden). Dept. of Plasma Physics)

    1991-01-01

    A collisionless plasma in the presence of two monochromatic electric fields is considered. By means of a kinetic analysis, a dispersion relation that governs the excitation of transverse electromagnetic fluctuations is derived and analysed. (orig.).

  9. Terahertz electromagnetic waves emitted from semiconductor investigated using terahertz time domain spectroscopy

    Institute of Scientific and Technical Information of China (English)

    Yiming Zhu; Songlin Zhuang

    2011-01-01

    Ultrafast electromagnetic waves radiated from semiconductor material under high electric fields and pho-toexcited by femtosecond laser pulses have been recorded by using terahertz time domain spectroscopy (THz-TDS). The waveforms of these electromagnetic waves reflect the dynamics of the photoexcited carriers in the semiconductor material, thus, THz-TDS provides a unique opportunity to observe directly the temporal and spatial evolutions of non-equilibrium transport of carriers within sub-picosecond time scale. We report on the observed THz emission waveforms emitted from GaAs by using a novel technology, the time domain THz electro-optic (EO) sampling, which has a bipolar feature, I.e., an initial positive peak and a subsequent negative dip that arises from its velocity overshoot. The initial positive peak has been interpreted as electron acceleration in the bottom of F valley in GaAs, where electrons have a light effective mass. The subsequent negative dip has been attributed to intervalley transfer from F to X and L valleys. Furthermore, the power dissipation spectra of the bulk GaAs in THz range are also investigated by using the Fourier transformation of the time domain THz traces. From the power dissipation spectra, the cutoff frequency for negative power dissipation (I.e., gain) under step electric field in the bulk GaAs can also be obtained. The cutoff frequency for the gain gradually increases with increasing electric fields up to 50 kV/cm and achieves saturation at approximately 1 THz at 300 K. Furthermore, based on the temperature dependence of the cutoff frequency, we find that this cutoff frequency is governed by the energy relaxation process of electrons from L to F valley via successive optical phonon emission.%1.Introduction Ultrafast non-equilibrium transport of carriers in semiconductors biased at high electric fields is of fundamental interest in semiconductor physics.From a fundamental point of view,the detailed understanding of the femtosecond

  10. Properties of Ternary One Dimensional Plasma Photomic Crystals for an Obliquely Incident Electromagnetic Wave Considering the Effect of Collisions in Plasma Layers

    Institute of Scientific and Technical Information of China (English)

    S. PRASAD; Vivek SINGH; A. K. SINGH

    2012-01-01

    An analytical study is presented on the modal dispersion characteristics, group velocity, and effective group, as well as the phase index of a ternary one dimensional plasma photonic crystal for an obliquely incident electromagnetic wave considering the effect of collisions in plasma layers. The dispersion relation is derived by using the transfer matrix method and the boundary conditions based on electromagnetic theory. The dispersion curves are plotted for both the normal photonic band gap structure and the absorption photonic band gap structure. It is found that the increase in the angle of incidence shifts the photonic band gap toward higher frequencies. Also, the cutoff frequency is independent of collisions.

  11. Assessment of a modified acoustic lens for electromagnetic shock wave lithotripters in a swine model.

    Science.gov (United States)

    Mancini, John G; Neisius, Andreas; Smith, Nathan; Sankin, Georgy; Astroza, Gaston M; Lipkin, Michael E; Simmons, W Neal; Preminger, Glenn M; Zhong, Pei

    2013-09-01

    The acoustic lens of the Modularis electromagnetic shock wave lithotripter (Siemens, Malvern, Pennsylvania) was modified to produce a pressure waveform and focal zone more closely resembling that of the original HM3 device (Dornier Medtech, Wessling, Germany). We assessed the newly designed acoustic lens in vivo in an animal model. Stone fragmentation and tissue injury produced by the original and modified lenses of the Modularis lithotripter were evaluated in a swine model under equivalent acoustic pulse energy (about 45 mJ) at 1 Hz pulse repetition frequency. Stone fragmentation was determined by the weight percent of stone fragments less than 2 mm. To assess tissue injury, shock wave treated kidneys were perfused, dehydrated, cast in paraffin wax and sectioned. Digital images were captured every 120 μm and processed to determine functional renal volume damage. After 500 shocks, the mean ± SD stone fragmentation efficiency produced by the original and modified lenses was 48% ± 12% and 52% ± 17%, respectively (p = 0.60). However, after 2,000 shocks, the modified lens showed significantly improved stone fragmentation compared to the original lens (mean 86% ± 10% vs 72% ± 12%, p = 0.02). Tissue injury caused by the original and modified lenses was minimal at a mean of 0.57% ± 0.44% and 0.25% ± 0.25%, respectively (p = 0.27). With lens modification the Modularis lithotripter demonstrates significantly improved stone fragmentation with minimal tissue injury at a clinically relevant acoustic pulse energy. This new lens design could potentially be retrofitted to existing lithotripters, improving the effectiveness of electromagnetic lithotripters. Copyright © 2013 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

  12. Modulation of a compressional electromagnetic wave in a magnetized electron-positron quantum plasma.

    Science.gov (United States)

    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.

  13. Single frequency spatial power combining using sparse array based on time reversal of electromagnetic wave%基于时间反演电磁波的稀疏阵列单频信号空间功率合成

    Institute of Scientific and Technical Information of China (English)

    陈秋菊; 姜秋喜; 曾芳玲; 宋长宝

    2015-01-01

    Based on time-reversal (TR) technique, the model of single frequency spatial power combining using sparse array is established. The efficiency function of spatial power combining is defined. The expression for the relationship of the statistical characteristics of combining efficiency at the time of maximum amplitude with the phase error and the number of array elements is derived. The analysis shows that when other parameters are determined, if the phase errors of the array nodes are mutually independent, and obey the uniform distribution to a certain extent, the combing efficiency’s mean would not be related to the number of array elements N , but related to the statistic parameter of phase error. The combing efficiency’s variance is related to not only the statistic parameter of phase errors, but also N . Once the statistic parameter of phase error is fixed, the greater the value of N , the smaller the variance is. So, in the engineering application, a large number of small power nodes could be used to reduce the phase error’s effect. In addition, the influence of phase error on the combining efficiency is investigated by both theoretical analysis and the numerical simulation. The results show that when the array elements work at the same frequency, polarization and antenna type, the parameter of phase error would affect the combing result. The smaller the parameter of phase error, the larger the power of the effective point is, and the more concentrative the effective points’ distribution is; the greater the parameter of phase error, the smaller the power of the effective point is, and the more dispersed the effective points’ distribution is. It is also seen that even though the phase error occurs, the spatial power combining can still be realized with the time reversal technique. The determination of the phase control precision is the compromise between the requirements and the possibility. The results presented in this paper are useful for

  14. Low-frequency fluid waves in fractures and pipes

    Energy Technology Data Exchange (ETDEWEB)

    Korneev, Valeri

    2010-09-01

    Low-frequency analytical solutions have been obtained for phase velocities of symmetrical fluid waves within both an infinite fracture and a pipe filled with a viscous fluid. Three different fluid wave regimes can exist in such objects, depending on the various combinations of parameters, such as fluid density, fluid viscosity, walls shear modulus, channel thickness, and frequency. Equations for velocities of all these regimes have explicit forms and are verified by comparisons with the exact solutions. The dominant role of fractures in rock permeability at field scales and the strong amplitude and frequency effects of Stoneley guided waves suggest the importance of including these wave effects into poroelastic theories.

  15. Design of Chaotic Cavities with Curved Wave Diffractors for Enhanced Low-Frequency Operation

    CERN Document Server

    Arnaut, L R

    2014-01-01

    Some numerical calculations are presented on the dependence of the average mode count and average mode density of electromagnetic cavities on their specific geometric design, based on the generalized Weyl law. The analysis focuses on a chaotic quasi-cubic cavity furnished with curved wave diffractors placed on its interior surface. The focus is on a design that increases the mode density and Q at relatively low frequencies. The results are of interest in reducing the `lowest usable frequency' and increasing the maximum field strength inside mode-stirred reverberation chambers.

  16. Electrogravitational Resonance of a Gaussian Beam to a High-Frequency Relic Gravitational Wave

    Institute of Scientific and Technical Information of China (English)

    李芳昱; 唐孟希

    2001-01-01

    We consider the resonant response of a Gaussian beam passing through a static magnetic field to a high-frequency relic gravitational wave (GW). It is found that under the synchroresonance condition, the first-order perturbative electromagnetic energy fluxes will contain a "left circular wave" and a "right circular wave" around the symmetrical axis of the Gaussian beam, but the perturbative effects produced by the + and × polarization of the GW have a different physical behaviour. For the high-frequency relic GW with vg = 1010 Hz, h = l0-30, recently expected by the quintessential inflationary models, the corresponding perturbative photon flux passing through the region 10-2 m2 would be expected to be 104 s-1. This is the largest perturbative photon flux we have recently analysed and estimated using the typical laboratory parameters.

  17. Electromagnetic transients as triggers in searches for gravitational waves from compact binary mergers

    CERN Document Server

    Kelley, Luke Zoltan; Ramirez-Ruiz, Enrico

    2013-01-01

    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 GRBs to signatures of r-process heating to optical and radio orphan afterglows. We compute the expected rates of multi-messenger observations in the Advanced detector era, and find that searches triggered on short GRBs --- with current high-energy instruments, such as Fermi --- and nucleosynthetic `kilonov...

  18. Anomalous Propagation of Electromagnetic Waves in Anisotropic Media with a Unique Dispersion Relation

    Institute of Scientific and Technical Information of China (English)

    SHU Wei-Xing; LUO Hai-Lu; LI Fei; REN Zhong-Zhou

    2006-01-01

    @@ We investigate the propagation of electromagnetic waves at the interface between an isotropic material and the anisotropic medium with a unique dispersion relation. We show that the refraction behaviour of E-polarized waves is opposite to that of H-polarized waves, though the dispersion relations for E- and H-polarized waves are the same. It is found that waves exhibit different propagation properties in anisotropic media with different sign combinations of the permittivity and permeability tensors. Some interesting properties of propagation are also found in the special anisotropic media, leading to potential applications.

  19. Effect of hydrostatic pressure and magnetic field on electromagnetically induced transparency based nonlinear frequency conversion in quantum ring

    Science.gov (United States)

    Gumber, Sukirti; Gambhir, Monica; Jha, Pradip Kumar; Mohan, Man

    2016-10-01

    We study the combined effect of hydrostatic pressure and magnetic field on electromagnetically induced transparency in quantum ring. The high flexibility in size and shape of ring makes it possible to fabricate a nearly perfect two-dimensional quantum structure. We also explore the dependence of frequency conversion, measured in terms of third order nonlinear susceptibility χ(3) , on coupling field, hydrostatic pressure and magnetic field. Although, a dip in χ(3) is observed with the introduction of strong coupling field, it renders the ring structure transparent to generated wave thus effectively enhancing the output of nonlinear frequency conversion process. At a fixed coupling strength, the output can be further enhanced by increasing the magnetic field while it shows an inverse relationship with pressure. These parameters, being externally controlled, provide an easy handle to control the output of quantum ring which can be used as frequency converter in communication networks.

  20. Ultrastructural Study on Ultra-Low Frequency Electromagnetic Fields and Transfer Factor Effects on Skin Ulcers

    Science.gov (United States)

    Cadena, M. S. Reyes; Chapul, L. Sánchez; Pérez, Javiér; García, M. N. Jiménez; López, M. A. Jiménez; Espíndola, M. E. Sánchez; Perez, R. Paniagua; Hernández, N. A.; Paniagua, G.; Uribe, F.; Nava, J. J. Godina; Segura, M. A. Rodríguez

    2008-08-01

    We determined the effect of 120Hz ultra low frequency electromagnetic field (ELF) on the healing process of skin in 20 Wistar rats distributed in four groups in which chronic dermal ulcers had been produced. The first two groups received a dose of the transfer factor and interferon-beta (IFN-β) every 24 h during 12 days. The third group (positive control) received only electromagnetic field (ELF) sessions, and in the fourth group (negative control), no treatment was applied. The electromagnetic field was applied through a Helmholtz coils; 30 Gauss of intensity. Results shown histological changes that improve the healing process in animals subjected to ELF together with the transfer factor.