Sample records for electromagnetism

  1. Electromagnets

    NSDL National Science Digital Library

    This is an activity about the properties of electromagnets, which is a crucial underpinning for understanding how magnetic fields are generated in nature, in the surface of the Sun, and in the interior of Earth. Learners will create an electromagnet by letting an electric current flow through a wire to generate a magnetic field, which is then detected using a compass. This activity requires a thin insulated wire, pencil, battery, compass and paper clips. This is Activity 2 of the Magnetism and Electromagnetism teachers guide.

  2. Electromagnetic Theory 1 /56 Electromagnetic Theory

    E-print Network

    Bicknell, Geoff

    Electromagnetic Theory 1 /56 Electromagnetic Theory Summary: · Maxwell's equations · EM Potentials · Equations of motion of particles in electromagnetic fields · Green's functions · Lienard-Weichert potentials · Spectral distribution of electromagnetic energy from an arbitrarily moving charge #12;Electromagnetic

  3. Electromagnetic Attraction.

    ERIC Educational Resources Information Center

    Milson, James L.

    1990-01-01

    Three activities involving electromagnetism are presented. Discussed are investigations involving the construction of an electromagnet, the effect of the number of turns of wire in the magnet, and the effect of the number of batteries in the circuit. Extension activities are suggested. (CW)

  4. Electromagnetic fasteners

    DOEpatents

    Crane, Randolph W. (Idaho Falls, ID); Marts, Donna J. (Idaho Falls, ID)

    1994-01-01

    An electromagnetic fastener for manipulating objects in space uses the matic attraction of various metals. An end effector is attached to a robotic manipulating system having an electromagnet such that when current is supplied to the electromagnet, the object is drawn and affixed to the end effector, and when the current is withheld, the object is released. The object to be manipulated includes a multiplicity of ferromagnetic patches at various locations to provide multiple areas for the effector on the manipulator to become affixed to the object. The ferromagnetic patches are sized relative to the object's geometry and mass.

  5. Electromagnetic fasteners

    DOEpatents

    Crane, Randolph W.; Marts, Donna J.

    1994-11-01

    An electromagnetic fastener for manipulating objects in space uses the matic attraction of various metals. An end effector is attached to a robotic manipulating system having an electromagnet such that when current is supplied to the electromagnet, the object is drawn and affixed to the end effector, and when the current is withheld, the object is released. The object to be manipulated includes a multiplicity of ferromagnetic patches at various locations to provide multiple areas for the effector on the manipulator to become affixed to the object. The ferromagnetic patches are sized relative to the object's geometry and mass.

  6. Electromagnetic Hypersensitivity

    Microsoft Academic Search

    Norbert Leitgeb

    \\u000a Electromagnetic hypersensitive persons (EHS) attribute their nonspecific health symptoms to environmental electromagnetic\\u000a fields (EMF) of different sources in or outside their homes. In general, causal attribution is not restricted to specific\\u000a EMF frequencies but involves a wide range from extremely low frequencies (ELF) up to radio frequencies (RF) including mobile\\u000a telecommunication microwaves and radar. EHS argue that existing exposure limits

  7. Electromagnetic casting

    SciTech Connect

    Evans, J.W.; Kageyama, R. [Univ. of California, Berkeley, CA (United States); Deepak [Motorola Corp., Phoenix, AZ (United States); Cook, D.P. [Reynolds Metals Co., Richmond, VA (United States); Prasso, D.C. [Intel Corp., Aloha, OR (United States); Nishioka, S. [NKK Corp., Kawasaki (Japan)

    1995-12-31

    Electromagnetic casting (EMC) is a technology that is used extensively in the aluminum industry to cast ingots with good surface finish for subsequent rolling into consumer product. The paper reviews briefly some investigations from the eighties wherein models for EMC were developed. Then more recent work is examined wherein more realistic 3D models have been developed, the traditional studies of electromagnetic and magnetohydrodynamic phenomena have been supplemented with research on heat transport, and the stability of the metal free surface has been examined. The paper concludes with three generalizations concerning modeling that may have wider applicability than EMC.

  8. Electromagnetic Geometry

    E-print Network

    M. Novello; F. T. Falciano; E. Goulart

    2011-11-08

    We show that Maxwell's electromagnetism can be mapped into the Born-Infeld theory in a curved space-time, which depends only on the electromagnetic field in a specific way. This map is valid for any value of the two lorentz invariants $F$ and $G$ confirming that we have included all possible solutions of Maxwell's equations. Our result seems to show that specifying the dynamics and the space-time structure of a given theory can be viewed merely as a choice of representation to describe the physical system.

  9. Electromagnet Lesson

    NSDL National Science Digital Library

    Orzali, Joe

    This hands-on classroom activity will help students understand the connections between magnets and electricity generation. The learning cycle planner includes an exploration phase with a hands-on activity and a suggested video. The concept development phase suggests showing the film "Who Killed the Electric Car?" The main part of this learning unit is the electromagnet lesson, which is a two day small group activity in which students will create an electromagnet. This document may be downloaded in PDF file format; student worksheets are included.

  10. Electromagnetic compatibility

    Microsoft Academic Search

    H. Maidment

    1980-01-01

    The historical background to the growth in problems of electromagnetic compatibility (EMC) in UK Military aircraft is reviewed and the present approach for minimizing these problems during development is discussed. The importance of using representative aircraft for final EMC assessments is stressed, and the methods of approach in planning and executing such tests are also outlined. The present equipment qualification

  11. Electromagnetic Survey

    USGS Multimedia Gallery

    USGS hydrologist conducts a broadband electromagnetic survey in New Orleans, Louisiana. The survey was one of several geophysical methods used during USGS applied research on the utility of the multi-channel analysis of surface waves (MASW) seismic method for non-invasive assessment of earthen levee...

  12. Electromagnetic Reciprocity.

    SciTech Connect

    Aldridge, David F.

    2014-11-01

    A reciprocity theorem is an explicit mathematical relationship between two different wavefields that can exist within the same space - time configuration. Reciprocity theorems provi de the theoretical underpinning for mod ern full waveform inversion solutions, and also suggest practical strategies for speed ing up large - scale numerical modeling of geophysical datasets . In the present work, several previously - developed electromagnetic r eciprocity theorems are generalized to accommodate a broader range of medi um, source , and receiver types. Reciprocity relations enabling the interchange of various types of point sources and point receivers within a three - dimensional electromagnetic model are derived. Two numerical modeling algorithms in current use are successfully tested for adherence to reciprocity. Finally, the reciprocity theorem forms the point of departure for a lengthy derivation of electromagnetic Frechet derivatives. These mathe matical objects quantify the sensitivity of geophysical electromagnetic data to variatio ns in medium parameters, and thus constitute indispensable tools for solution of the full waveform inverse problem. ACKNOWLEDGEMENTS Sandia National Labor atories is a multi - program 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. Signif icant portions of the work reported herein were conducted under a Cooperative Research and Development Agreement (CRADA) between Sandia National Laboratories (SNL) and CARBO Ceramics Incorporated. The author acknowledges Mr. Chad Cannan and Mr. Terry Pa lisch of CARBO Ceramics, and Ms. Amy Halloran, manager of SNL's Geophysics and Atmospheric Sciences Department, for their interest in and encouragement of this work. Special thanks are due to Dr . Lewis C. Bartel ( recently retired from Sandia National Labo ratories and now a geophysical consultant ) and Dr. Chester J. Weiss (recently rejoined with Sandia National Laboratories) for many stimulating (and reciprocal!) discussions regar ding the topic at hand.

  13. Electromagnetic Spectrum

    NSDL National Science Digital Library

    Part of the larger Imagine the Universe educational site, the Electromagnetic Spectrum site is another great resource from NASA. The site gives clear and easy-to-understand explanations, while providing keywords throughout the page that are linked to a dictionary of terms for easy access to further information. Students will enjoy the colorful illustrations accompanying the text, which vertically follow the spectrum from radio to gamma rays, while teachers will appreciate the related lesson plans link that will help reinforce the learning.

  14. Electromagnetic leptogenesis

    NASA Astrophysics Data System (ADS)

    Bell, Nicole F.; Kayser, Boris J.; Law, Sandy S. C.

    2008-10-01

    We present a new leptogenesis scenario, where the lepton asymmetry is generated by CP-violating decays of heavy electroweak singlet neutrinos via electromagnetic dipole moment couplings to the ordinary light neutrinos. Akin to the usual scenario where the decays are mediated through Yukawa interactions, we have shown, by explicit calculations, that the desired asymmetry can be produced through the interference of the corresponding tree-level and one-loop decay amplitudes involving the effective dipole moment operators. We also find that the relationship of the leptogenesis scale to the light neutrino masses is similar to that for the standard Yukawa-mediated mechanism.

  15. Creating an Electromagnet

    NSDL National Science Digital Library

    2014-09-18

    Student teams investigate the properties of electromagnets. They create their own small electromagnet and experiment with ways to change its strength to pick up more paper clips. Students learn about ways that engineers use electromagnets in everyday applications.

  16. Electromagnetic Field Theory

    E-print Network

    Hart, Gus

    Electromagnetic Field Theory BO THIDÉ UPSILON BOOKS #12;#12;ELECTROMAGNETIC FIELD THEORY #12;#12;Electromagnetic Field Theory BO THIDÉ Swedish Institute of Space Physics and Department of Astronomy and Space, Sweden UPSILON BOOKS · COMMUNA AB · UPPSALA · SWEDEN #12;Also available ELECTROMAGNETIC FIELD THEORY

  17. Electromagnetic Gravitation

    NASA Astrophysics Data System (ADS)

    Montgomery, Jerry; Russell, Philmore

    2005-03-01

    Recent analysis of radio metric data from several space probes deployed by NASA indicate that they are being slowed by an anomalous constant acceleration with an average magnitude of 8x10-10m/s^2 oriented with respect to the sun. Analysis of their slowdown, in addition to many other anomalous astrophysical phenomena indicates that a negative curvature of the space-time continuum is produced by the electromagnetic radiation of the sun. The acceleration appears to have a close relation to the wavelength ?at which the sun radiates most intensely. The evidence that supports our hypothesis may also provide solutions to the flat rotation curve of the galaxy, and rogue stars and planets within the galaxy. Calculations using the data concerning the four probes result in the formula -a=c^2? which expresses a negative acceleration that is proportional to the speed of light divided by the peak wavelength, multiplied by a new constant k. The evidence also gives a strong indication that light, in addition to its particle-wave nature, produces gravitational field-like characteristics through interacting with the space-time continuum.

  18. Electromagnetic gravitation

    NASA Astrophysics Data System (ADS)

    Montgomery, Jerry, , Dr.

    2005-04-01

    Recent analysis of radio metric data from several space probes deployed by NASA indicate that they are being slowed by an anomalous constant acceleration with an average magnitude of 8x10-10m/s^2 oriented with respect to the sun. Analysis of their slowdown, in addition to many other anomalous astrophysical phenomena indicates that a negative curvature of the space-time continuum is produced by the electromagnetic radiation of the sun. The acceleration appears to have a close relation to the wavelength ?at which the sun radiates most intensely. The evidence that supports our hypothesis may also provide solutions to the flat rotation curve of the galaxy, and rogue stars and planets within the galaxy. Calculations using the data concerning the four probes result in the formula -a=c^2? which expresses a negative acceleration that is proportional to the speed of light divided by the peak wavelength, multiplied by a new constant k. The evidence also gives a strong indication that light, in addition to its particle-wave nature, produces gravitational field-like characteristics through interacting with the space-time continuum.

  19. The Electromagnetic Spectrum: FRONTLINE

    NSDL National Science Digital Library

    2004-02-20

    This video segment adapted from FRONTLINE introduces the electromagnetic spectrum and explains how the various types of electromagnetic waves are distinguished by the amount of energy each wave carries.

  20. Electromagnetic induction methods

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Electromagnetic induction geophysical methods are finding greater and greater use for agricultural purposes. Electromagnetic induction methods measure the electrical conductivity (or resistivity) for a bulk volume of soil directly beneath the surface. An instrument called a ground conductivity meter...

  1. Electromagnetic properties of neutrinos

    E-print Network

    Carlo Giunti; Alexander Studenikin

    2010-06-08

    A short review on electromagnetic properties of neutrinos is presented. In spite of many efforts in the theoretical and experimental studies of neutrino electromagnetic properties, they still remain one of the main puzzles related to neutrinos.

  2. Investigation of electromagnetic welding

    E-print Network

    Pressl, Daniel G. (Daniel Gerd)

    2009-01-01

    We propose several methodologies to study and optimize the electromagnetic process for Electromagnetic Forming (EMF) and Welding (EMW), thereby lowering the necessary process energy up to a factor of three and lengthening ...

  3. Electromagnetic Interference (Emi)

    Microsoft Academic Search

    Mike Hardage; Philip D. Henry

    \\u000a Electric and magnetic signals originating outside of a defibrillator may affect its operation, a phenomenon known as electromagnetic\\u000a interference (EMI). EMI usually refers to interference from environmental electromagnetic instrumentation and should be distinguished\\u000a from other sources of electromagnetic noise causing ICD malfunction (Table 1). Signals most likely to penetrate and affect\\u000a pacemakers and ICDs are electromagnetic waves or signals at

  4. Electromagnetic Abdulaziz Hanif

    E-print Network

    Masoudi, Husain M.

    Electromagnetic Propulsion Abdulaziz Hanif Electrical Engineering Department King Fahd University of spacecraft, which would be jolted through space by electromagnets, could take us farther than any of these other methods. When cooled to extremely low temperatures, electromagnets demonstrate an unusual behavior

  5. Electromagnetic Measurements at RHIC

    E-print Network

    Hamagaki, Hideki

    Electromagnetic Measurements at RHIC Hideki Hamagaki Center for Nuclear Study University of Tokyo #12;2/10/2005 "Electromagnetic measurements at RHIC"@ICPAQGP 05 Hideki Hamagaki 2 Prologue · EM probe and where they are produced; #12;2/10/2005 "Electromagnetic measurements at RHIC"@ICPAQGP 05 Hideki Hamagaki

  6. Electromagnetic Measurements at RHIC

    E-print Network

    Hamagaki, Hideki

    Electromagnetic Measurements at RHIC Hideki Hamagaki Center for Nuclear Study Graduate School of Science the University of Tokyo #12;2006/06/29 "Electromagnetic measurements at RHIC"@ATHIC 2006 Hideki;2006/06/29 "Electromagnetic measurements at RHIC"@ATHIC 2006 Hideki Hamagaki 3 Prologue ­ scope of EM measurements · EM

  7. Electromagnetic structure of pion

    SciTech Connect

    Mello, Clayton S.; Cruz Filho, Jose P.; Da Silva, Edson O.; El-Bennich, Bruno; De Melo, J. P.; Filho, Victo S. [Laboratorio de Fisica Teorica e Computacional (LFTC), Universidade Cruzeiro do Sul, 01506-000, Sao Paulo (Brazil)

    2013-03-25

    In this work, we analyze the electromagnetic structure of the pion, an elementary particle composed by a quark-antiquark bound state, by considering the calculation of its electromagnetic radius and its electromagnetic form factor in low and intermediate energy range. Such observables are determined by means of a theoretical model that takes into account the constituent quark and antiquark of the pion, in the formalism of the light-front field theory. In particular, it is considered a nonsymmetrical vertex for such a model, in which we have calculated the electromagnetic form factor of the pion in an optimized way, by varying its regulator mass, so that we can obtain the best value for the pion electromagnetic radius when compared with the experimental one. The theoretical calculations are also compared with the most recent experimental data involving the pion electromagnetic form factor and the results show very good agreement.

  8. 8.07 Electromagnetism II, Fall 2002

    E-print Network

    Zwiebach, Barton

    Survey of basic electromagnetic phenomena: electrostatics, magnetostatics; electromagnetic properties of matter. Time-dependent electromagnetic fields and Maxwell's equations. Electromagnetic waves, emission, absorption, ...

  9. "Hearing" Electromagnetic Waves

    NASA Astrophysics Data System (ADS)

    Rojo, Marta; Muńoz, Juan

    2014-12-01

    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 waves. Moreover, students learn about the importance and historical development of communication systems, the basic principles of communication links, and the procedure to send information through an electromagnetic wave.1,2

  10. Meson electromagnetic form factors

    E-print Network

    Stanislav Dubnicka; Anna Z. Dubnickova

    2012-10-23

    The electromagnetic structure of the pseudoscalar meson nonet is completely described by the sophisticated Unitary&Analytic model, respecting all known theoretical properties of the corresponding form factors.

  11. Vertical electromagnetic profiling (VEMP)

    Microsoft Academic Search

    Lytle

    1984-01-01

    Vertical seismic profiling (VSP) is based upon reception measurements performed in a borehole with a source near the ground surface. This technology has seen a surge in application and development in the last decade. The analogous concept of vertical electromagnetic profiling (VEMP) consists of reception measurements performed in a borehole with a source near the ground surface. Although the electromagnetic

  12. Building an Electromagnet

    NSDL National Science Digital Library

    VU Bioengineering RET Program,

    Students design and construct an electromagnet that must pick up 10 staples. They begin with only minimal guidance, and after the basic concept is understood, are informed of the properties that affect the strength of that magnet. They conclude by designing their own electromagnet to complete the challenge of separating scrap steel from scrap aluminum for recycling and share it with the class.

  13. The Electromagnetic Spectrum

    NSDL National Science Digital Library

    2012-08-03

    This is a lesson about the electromagnetic spectrum. Learners will read two pages of information about the electromagnetic spectrum and answer questions in an accompanying worksheet. This activity is from the Stanford Solar Center's All About the Sun: Sun and Stars activity guide for Grades 5-8 and can also accompany the Stanford Solar Center's Build Your Own Spectroscope activity.

  14. Introducing Electromagnetic Field Momentum

    ERIC Educational Resources Information Center

    Hu, Ben Yu-Kuang

    2012-01-01

    I describe an elementary way of introducing electromagnetic field momentum. By considering a system of a long solenoid and line charge, the dependence of the field momentum on the electric and magnetic fields can be deduced. I obtain the electromagnetic angular momentum for a point charge and magnetic monopole pair partially through dimensional…

  15. Electromagnetic Analysis: Concrete Results

    Microsoft Academic Search

    Karine Gandolfi; Christophe Mourtel; Francis Olivier

    2001-01-01

    Abstract Although the possibility of attacking smart - cards by analyz - ing their electromagnetic power radiation repeatedly appears in research papers, all accessible references evade the essence of reporting conclusive experiments where actual cryptographic algorithms such as des or rsa were successfully attacked This work describes electromagnetic experiments conducted on three dif - ferent cmos chips, featuring di erent

  16. "Hearing" Electromagnetic Waves

    ERIC Educational Resources Information Center

    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…

  17. EE335 Electromagnetic Interference Electromagnetic Interference (EMI)

    E-print Network

    Kaiser, Todd J.

    Electromagnetic Compatibility (EMC): The capability of electrical and electronic devices to operate of EMI EMI is the lack of EMC. EMI requirements 1) Source that generates noise 2) Coupling path to transmit the noise a. Radiated b. Conducted 3) Receptor that is susceptible to noise Interference Sources 1

  18. Gravito-electromagnetic resonances

    E-print Network

    Christos G. Tsagas

    2011-08-10

    The interaction between gravitational and electromagnetic radiation has a rather long research history. It is well known, in particular, that gravity-wave distortions can drive propagating electromagnetic signals. Since forced oscillations provide the natural stage for resonances to occur, gravito-electromagnetic resonances have been investigated as a means of more efficient gravity-wave detection methods. In this report, we consider the coupling between the Weyl and the Maxwell fields on a Minkowski background, which also applies to astrophysical environments where gravity is weak, at the second perturbative level. We use covariant methods that describe gravitational waves via the transverse component of the shear, instead of pure-tensor metric perturbations. The aim is to calculate the properties of the electromagnetic signal, which emerges from the interaction of its linear counterpart with an incoming gravitational wave. Our analysis shows how the wavelength and the amplitude of the gravitationally driven electromagnetic wave vary with the initial conditions. More specifically, for certain initial data, the amplitude of the induced electromagnetic signal is found to diverge. Analogous, diverging, gravito-electromagnetic resonances were also reported in cosmology. Given that, we extend our Minkowski-space study to cosmology and discuss analogies and differences in the physics and in the phenomenology of the Weyl-Maxwell coupling between the aforementioned two physical environments.

  19. I. What is electromagnetic radiation and the electromagnetic spectrum?

    E-print Network

    Sitko, Michael L.

    i­1 I. What is electromagnetic radiation and the electromagnetic spectrum? What do light, X effects on matter. This "stuff" is called electromagnetic radiation, because it travels (radiates) and has electrical and magnetic effects. Electromagnetic radiation is the means for many of our interactions

  20. Vertical electromagnetic profiling (VEMP)

    SciTech Connect

    Lytle, R.J.

    1984-08-01

    Vertical seismic profiling (VSP) is based upon reception measurements performed in a borehole with a source near the ground surface. This technology has seen a surge in application and development in the last decade. The analogous concept of vertical electromagnetic profiling (VEMP) consists of reception measurements performed in a borehole with a source near the ground surface. Although the electromagnetic concept has seen some application, this technology has not been as systematically developed and applied as VSP. Vertical electromagnetic profiling provides distinct and complementary data due to sensing different physical parameters than seismic profiling. Certain of the advantages of VEMP are presented. 28 references, 7 figures.

  1. Inverse problems in electromagnetics

    E-print Network

    Chen, Xudong, 1977-

    2005-01-01

    Two inverse problems in electromagnetics are investigated in this thesis. The first is the retrieval of the effective constitutive parameters of metamaterials from the measurement of the reflection and the transmission ...

  2. Purely electromagnetic spacetimes

    E-print Network

    B. V. Ivanov

    2007-12-15

    Electrovacuum solutions devoid of usual mass sources are classified in the case of one, two and three commuting Killing vectors. Three branches of solutions exist. Electromagnetically induced mass terms appear in some of them.

  3. Electromagnetism in the Movies.

    ERIC Educational Resources Information Center

    Everitt, Lori R.; Patterson, Evelyn T.

    1999-01-01

    Describes how the authors used portions of popular movies to help students review concepts related to electromagnetism. Movies used and concepts covered in the review are listed, and a sample activity is described. (WRM)

  4. The classical geometrization electromagnetism

    E-print Network

    C. A. Duarte

    2015-02-11

    Following the line of the history, if by one side the electromagnetic theory was consolidated on the 19th century, the emergence of the special and the general relativity theories on the 20th century opened possibilities of further developments, with the search for the unification of the gravitation and the electromagnetism on a single unified theory. Some attempts to the geometrization of the electromagnetism emerged in this context, where these first models resided strictly on a classical basis. Posteriorly, they were followed by more complete and embracing quantum field theories. The present work reconsiders the classical viewpoint, with the purpose of showing that in a first order of approximation the electromagnetism constitutes a geometric structure aside other phenomena as gravitation. Even though being limited, the model is consistent and offers the possibility of an experimental test of validity.

  5. Purely electromagnetic spacetimes

    SciTech Connect

    Ivanov, B. V. [Institute for Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences Tzarigradsko Shausse 72, Sofia 1784 (Bulgaria)

    2008-02-15

    The Rainich's program of describing metrics induced by pure electromagnetic fields is implemented in a simpler way by using the Ernst formalism and increasing the symmetry of spacetime. Stationary metrics possessing one, two or three Killing vectors are studied and classified. Three branches of solutions exist. Electromagnetically induced mass terms appear in two of them, including a class of solutions in harmonic functions. The static subcase is discussed too. Relations to other well-known electrovacuum metrics are elucidated.

  6. Electromagnetic nonuniformly correlated beams.

    PubMed

    Tong, Zhisong; Korotkova, Olga

    2012-10-01

    A class of electromagnetic sources with nonuniformly distributed field correlations is introduced. The conditions on source parameters guaranteeing that the source generates a physical beam are derived. It is shown that the new sources are capable of producing beams with polarization properties that evolve on propagation in a manner much more complex compared to the well-known electromagnetic Gaussian Schell-model beams. PMID:23201663

  7. Electromagnetic rotational actuation.

    SciTech Connect

    Hogan, Alexander Lee

    2010-08-01

    There are many applications that need a meso-scale rotational actuator. These applications have been left by the wayside because of the lack of actuation at this scale. Sandia National Laboratories has many unique fabrication technologies that could be used to create an electromagnetic actuator at this scale. There are also many designs to be explored. In this internship exploration of the designs and fabrications technologies to find an inexpensive design that can be used for prototyping the electromagnetic rotational actuator.

  8. Electromagnetic acoustic transduction using a pulsed electromagnet

    NASA Astrophysics Data System (ADS)

    Palmer, S. B.; Hernandez-Valle, J. F.; Dixon, S.

    2009-03-01

    Some early designs of Electromagnetic Acoustic Transducers (EMATs) used electromagnets to provide the strong magnetic field required for the transducer to operate. The advent of a new generation of permanent magnets such as NdFeB, with magnetic fields approaching 1T, meant that many EMAT designs switched over to using these small, compact and relatively inexpensive magnets. Typically, most modern EMATs make use of permanent magnets since they can exert high magnetic fields with compact structures. There are certain limitations when using permanent magnets, and their low Curie points of between 80-150C limit their practicality for high temperature testing without using water cooled transducers. In this work we have employed a pulsed electromagnet to provide the magnetic field. Pulsing the magnet dramatically reduces the average power required, keeping the supply more compact and less complex. It has the added advantage on ferritic steels, of resulting in much larger amplitude ultrasonic signals and improved signal to noise when compared with EMATs which use the strongest permanent magnets available.

  9. Electromagnetic attachment mechanism

    NASA Technical Reports Server (NTRS)

    Monford, Leo G., Jr. (inventor)

    1992-01-01

    An electromagnetic attachment mechanism is disclosed for use as an end effector of a remote manipulator system. A pair of electromagnets, each with a U-shaped magnetic core with a pull-in coil and two holding coils, are mounted by a spring suspension system on a base plate of the mechanism housing with end pole pieces adapted to move through openings in the base plate when the attractive force of the electromagnets is exerted on a strike plate of a grapple fixture affixed to a target object. The pole pieces are spaced by an air gap from the strike plate when the mechanism first contacts the grapple fixture. An individual control circuit and power source is provided for the pull-in coil and one holding coil of each electromagnet. A back-up control circuit connected to the two power sources and a third power source is provided for the remaining holding coils. When energized, the pull-in coils overcome the suspension system and air gap and are automatically de-energized when the pole pieces move to grapple and impose a preload force across the grapple interface. A battery backup is a redundant power source for each electromagnet in each individual control circuit and is automatically connected upon failure of the primary source. A centerline mounted camera and video monitor are used in cooperation with a target pattern on the reflective surface of the strike plate to effect targeting and alignment.

  10. Electrosensibility and electromagnetic hypersensitivity.

    PubMed

    Leitgeb, Norbert; Schröttner, Jörg

    2003-09-01

    Electromagnetic sensibility, the ability to perceive electric and electromagnetic exposure, and electromagnetic hypersensitivity (EHS), developing health symptoms due to exposure to environmental electromagnetic fields, need to be distinguished. Increased electrosensibility is a necessary, however, not a sufficient condition for electromagnetic hypersensitivity. At an extended sample of the general population of 708 adults, including 349 men and 359 women aged between 17 and 60 years, electrosensibility was investigated and characterized by perception threshold and its standard deviation. By analyzing the probability distributions of the perception threshold of electric 50 Hz currents, evidence could be found for the existence of a subgroup of people with significantly increased electrosensibility (hypersensibility) who as a group could be differentiated from the general population. The presented data show that the variation of the electrosensibility among the general population is significantly larger than has yet been estimated by nonionizing radiation protection bodies, but much smaller than claimed by hypersensitivity self-aid groups. These quantitative results should contribute to a less emotional discussion of this problem. The investigation method presented, is capable of exclusion diagnostics for persons suffering from the hypersensitivity syndrome. PMID:12929157

  11. Neutrino electromagnetic properties

    SciTech Connect

    Giunti, C., E-mail: giunti@to.infn.i [University of Turin, INFN, Section of Turin (Italy); Studenikin, A., E-mail: studenik@srd.sinp.msu.r [Moscow State University, Department of Theoretical Physics (Russian Federation)

    2009-12-15

    The main goal of the paper is to give a short review on neutrino electromagnetic properties. In the introductory part of the paper a summary on what we really know about neutrinos is given: we discuss the basics of neutrino mass and mixing as well as the phenomenology of neutrino oscillations. This is important for the following discussion on neutrino electromagnetic properties that starts with a derivation of the neutrino electromagnetic vertex function in the most general form, that follows from the requirement of Lorentz invariance, for both the Dirac and Majorana cases. Then, the problem of the neutrino form factor definition and calculation within gauge models is considered. In particular, we discuss the neutrino electric charge form factor and charge radius, dipole magnetic and electric and anapole form factors. Available experimental constraints on neutrino electromagnetic properties are also discussed, and the recently obtained experimental limits on neutrino magnetic moments are reviewed. The most important neutrino electromagnetic processes involving a direct neutrino coupling with photons (such as neutrino radiative decay, neutrino Cherenkov radiation, spin light of neutrino and plasmon decay into neutrino-antineutrino pair in media) and neutrino resonant spin-flavor precession in a magnetic field are discussed at the end of the paper.

  12. Electromagnetic Energy Sink

    E-print Network

    Valagiannopoulos, Constantinos A; Simovski, Constantin R; Tretyakov, Sergei A; Maslovski, Stanislav I

    2015-01-01

    The ideal black body fully absorbs all incident rays, that is, all propagating waves created by arbitrary sources. The known idealized realization of a black body is the perfectly matched layer (PML), widely used in numerical electromagnetics. However, ideal black bodies and PMLs do not interact with evanescent fields existing near any finite-size source, and the energy stored in these fields cannot be harvested. Here we introduce the concept of the ideal conjugate matched layer (CML), which fully absorbs energy of both propagating and evanescent fields of sources acting as an ideal sink for electromagnetic energy. Conjugate matched absorbers have exciting application potentials, as resonant attractors of electromagnetic energy into the absorber volume. We derive the conditions on the constitutive parameters of media which can serve as CML materials, numerically study the performance of planar and cylindrical CML and discuss possible realizations of such materials as metal-dielectric composites.

  13. Electromagnetic properties of baryons

    SciTech Connect

    Ledwig, T.; Pascalutsa, V.; Vanderhaeghen, M. [Institut fuer Kernphysik, Universitaet Mainz, D-55099 Mainz (Germany); Martin-Camalich, J. [Departamento de Fisica Teorica and IFIC, Universidad de Valencia-CSIC, Spain and Department of Physics and Astronomy, University of Sussex, BN1 9Qh, Brighton (United Kingdom)

    2011-10-21

    We discuss the chiral behavior of the nucleon and {Delta}(1232) electromagnetic properties within the framework of a SU(2) covariant baryon chiral perturbation theory. Our one-loop calculation is complete to the order p{sup 3} and p{sup 4}/{Delta} with {Delta} as the {Delta}(1232)-nucleon energy gap. We show that the magnetic moment of a resonance can be defined by the linear energy shift only when an additional relation between the involved masses and the applied magnetic field strength is fulfilled. Singularities and cusps in the pion mass dependence of the {Delta}(1232) electromagnetic moments reflect a non-fulfillment. We show results for the pion mass dependence of the nucleon iso-vector electromagnetic quantities and present preliminary results for finite volume effects on the iso-vector anomalous magnetic moment.

  14. Improved Electromagnetic Brake

    NASA Technical Reports Server (NTRS)

    Martin, Toby B.

    2004-01-01

    A proposed design for an electromagnetic brake would increase the reliability while reducing the number of parts and the weight, relative to a prior commercially available electromagnetic brake. The reductions of weight and the number of parts could also lead to a reduction of cost. A description of the commercial brake is prerequisite to a description of the proposed electromagnetic brake. The commercial brake (see upper part of figure) includes (1) a permanent magnet and an electromagnet coil on a stator and (2) a rotor that includes a steel contact plate mounted, with tension spring loading, on an aluminum hub. The stator is mounted securely on a stationary object, which would ordinarily be the housing of a gear drive or a motor. The rotor is mounted on the shaft of the gear drive or motor. The commercial brake nominally operates in a fail-safe (in the sense of normally braking) mode: In the absence of current in the electromagnet coil, the permanent magnet pulls the contact plate, against the spring tension, into contact with the stator. To release the brake, one excites the electromagnet with a current of the magnitude and polarity chosen to cancel the magnetic flux of the permanent magnet, thereby enabling the spring tension to pull the contact plate out of contact with the stator. The fail-safe operation of the commercial brake depends on careful mounting of the rotor in relation to the stator. The rotor/stator gap must be set with a tolerance between 10 and 15 mils (between about 0.25 and about 0.38 mm). If the gap or the contact pad is thicker than the maximum allowable value, then the permanent magnetic field will not be strong enough to pull the steel plate across the gap. (For this reason, any contact pad between the contact plate and the stator must also be correspondingly thin.) If the gap exceeds the maximum allowable value because of shaft end play, it becomes impossible to set the brake by turning off the electromagnet current. Although it may still be possible to set the brake by applying an electromagnet current to aid the permanent magnetic field instead of canceling it, this action can mask an out-of-tolerance condition in the brake and it does not restore the fail-safe function of setting the brake when current is lost.

  15. 8.07 Electromagnetism II, Fall 2005

    E-print Network

    Bertschinger, Edmund

    This course is the second in a series on Electromagnetism beginning with Electromagnetism I (8.02 or 8.022). It is a survey of basic electromagnetic phenomena: electrostatics; magnetostatics; electromagnetic properties of ...

  16. Electromagnetically Induced Flows Michiel de Reus

    E-print Network

    Vuik, Kees

    Electromagnetically Induced Flows in Water Michiel de Reus 8 maart 2013 () Electromagnetically Conclusion and future research () Electromagnetically Induced Flows 2 / 56 #12;1 Introduction 2 Maxwell Navier Stokes equations 5 Simulations 6 Conclusion and future research () Electromagnetically Induced

  17. Electromagnetic Radiation REFERENCE: Remote Sensing of

    E-print Network

    Gilbes, Fernando

    1 CHAPTER 2: Electromagnetic Radiation Principles REFERENCE: Remote Sensing of the Environment John;2 Electromagnetic Energy Interactions Energy recorded by remote sensing systems undergoes fundamental interactions, creating convectional currents in the atmosphere. c) Electromagnetic energy in the form of electromagnetic

  18. Electromagnetic mass accelerators

    Microsoft Academic Search

    Pavel V. Kasyanenko; Vasily A. Efremov; Sergey A. Kharitonov

    2010-01-01

    The powerful power supplies system (up to 3 - 4 GW in impulse) was developed for the electromagnetic mass accelerator. Unique blocks of repeated switching rated on high currents (up to 1.2MA and voltage up to 5KV) are considered. In this paper various designs of the mass accelerator system and its power supplies are described.

  19. Computation of electromagnetic transients

    Microsoft Academic Search

    HERMANN W. DOMMEL; W. SCOTT MEYER

    1974-01-01

    Switching operations, faults, and other disturbances produce surges on transmission lines and oscillations in transformer and generator windings. Such electromagnetic transients have primarily been studied with transient network analyzers since the late 1930's. In recent years, digital computer programs have been de-. veloped which make simulation by digital computer competitive. The solution techniques of such programs are described, and their

  20. Electromagnetic pulsar spindown

    E-print Network

    I. Contopoulos

    2007-01-10

    We evaluate the result of the recent pioneering numerical simulations in Spitkovsky~2006 on the spindown of an oblique relativistic magnetic dipole rotator. Our discussion is based on our experience from two idealized cases, that of an aligned dipole rotator, and that of an oblique split-monopole rotator. We conclude that the issue of electromagnetic pulsar spindown may not have been resolved yet.

  1. Equivalence principles and electromagnetism

    NASA Technical Reports Server (NTRS)

    Ni, W.-T.

    1977-01-01

    The implications of the weak equivalence principles are investigated in detail for electromagnetic systems in a general framework. In particular, it is shown that the universality of free-fall trajectories (Galileo weak equivalence principle) does not imply the validity of the Einstein equivalence principle. However, the Galileo principle plus the universality of free-fall rotation states does imply the Einstein principle.

  2. Electromagnetism and Gravitation

    E-print Network

    Kenneth Dalton

    1997-03-10

    The classical concept of "mass density" is not fundamental to the quantum theory of matter. Therefore, mass density cannot be the source of gravitation. Here, we treat electromagnetic energy, momentum, and stress as its source. The resulting theory predicts that the gravitational potential near any charged elementary particle is many orders of magnitude greater than the Newtonian value.

  3. Electromagnetic brain mapping

    Microsoft Academic Search

    S. Baillet; J. C. Mosher; R. M. Leahy

    2001-01-01

    There has been tremendous advances in our ability to produce images of human brain function. Applications of functional brain imaging extend from improving our understanding of the basic mechanisms of cognitive processes to better characterization of pathologies that impair normal function. Magnetoencephalography (MEG) and electroencephalography (EEG) (MEG\\/EEG) localize neural electrical activity using noninvasive measurements of external electromagnetic signals. Among the

  4. What are Electromagnetic Metamaterials?

    NSDL National Science Digital Library

    Metamaterials are artificial structures that display properties beyond those available in naturally occuring materials. Materials interact with light and other electromagnetic fields. Because of this, materials can be used to control light in various ways, forming the basis for optical devices. This website from Duke University gives more details and graphs.

  5. Electromagnetic Compatibility Operational System (EMCOPS)

    Microsoft Academic Search

    T. E. Cherot

    1968-01-01

    A system has been developed to provide electromagnetic compatibility for military frequency usage throughout an extensive geographic area. This system employs a digital computer and an extensive data base of electromagnetic equipment parameters to perform real-time frequency usage analysis. Electromagnetic interference is identified and controlled by a subsystem that includes frequency-scanning surveillance receivers having their digital outputs linked to the

  6. Electromagnetically induced photonic band gap

    Microsoft Academic Search

    Yuri V. Rostovtsev; Andrey B. Matsko; Marlan O. Scully

    1999-01-01

    A nonlinear propagation of electromagnetic waves has been investigated in a heterostructure formed by spatially modulated density of ladder-type (Xi) three-level atoms. The appearance of a forbidden band gap for an electromagnetic field induced by another electromagnetic field has been found. An alternative concept of an optical transistorlike device based on this effect has been proposed.

  7. Electromagnetic Environment of Grounding Systems

    NASA Astrophysics Data System (ADS)

    Lefouili, M.; Hafsaoui, I.; Kerroum, K.; Drissi, K. El Khamlichi

    Electromagnetic compatibility (EMC) and lightning protection studies in large installations require knowledge of spatial and temporal distribution of electromagnetic fields in case of lightning and power system faults. A new hybrid method for modeling electromagnetic environment of grounding systems is developed in this work. The electromagnetic fields in the surrounding soil are determined from the previously calculated current distribution using dipoles theory with analytical formulas. The model can be used to predict the EM environment of grounding systems because it can calculate electromagnetic fields in any points of interest.

  8. Electromagnetic heating of Io

    NASA Astrophysics Data System (ADS)

    Colburn, D. S.

    1980-12-01

    The electromagnetic heating of the Io interior is considered as an alternative to tidal dissipation to account for the observed volcanic activity. The characteristics of the time-varying magnetic field of Jupiter as seen from Io are discussed, and the range of possible rock conductivities is examined. Interior heating due to the transverse electric and transverse magnetic modes is calculated. It is found that the TM mode appears to be insignificant as a heating source due to the high conductivity of the ionosphere, even when TM heating is concentrated in local hot regions. The TE mode is a more promising source of heating, although electromagnetic heating by either mode does not appear significant in comparison with other heat sources at present.

  9. Electromagnetic targeting of guns

    SciTech Connect

    Pogue, E.W.; Boat, R.M.; Holden, D.N.; Lopez, J.R. [and others

    1996-10-01

    This is the final report of a one-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). Electromagnetic pulse (EMP) signals produced from explosives being fired have been reported in the literature for fifty years. When a gun is fired it produces an EMP muzzle blast signal. The strength and nature of these signals was first analyzed in the early 1970s, while the results were interesting, no follow-up studies were conducted. With modern detection and signal processing technology, we believe that these signals could be used to instantaneously locate guns of virtually all calibers as they fire. The objective of our one-year project was to establish the basic nature of these signals and their utility in the concept of electromagnetic targeting of guns.

  10. Electromagnetically Induced Entanglement

    E-print Network

    Xihua Yang; Min Xiao

    2015-05-18

    We present a novel quantum phenomenon named electromagnetically induced entanglement in the conventional Lambda-type three-level atomic system driven by a strong pump field and a relatively weak probe field. Nearly perfect entanglement between the pump and probe fields can be achieved with a low coherence decay rate between the two lower levels, high pump-field intensity, and large optical depth of the atomic ensemble. The physical origin is quantum coherence between the lower doublet produced by the pump and probe fields, similar to the well-known electromagnetically induced transparency. This method would greatly facilitate the generation of nondegenerate narrow-band continuous-variable entanglement between bright light beams by using only coherent laser fields, and may find potential and broad applications in realistic quantum information processing.

  11. Magnetism and Electromagnetism

    NSDL National Science Digital Library

    Kuphaldt, Tony R.

    All About Circuits is a website that ā??provides a series of online textbooks covering electricity and electronics.ā? Written by Tony R. Kuphaldt, the textbooks available here are wonderful resources for students, teachers, and anyone who is interested in learning more about electronics. This specific section, Magnetism and Electromagnetism, is the fourteenth chapter in Volume I ā?? Direct Current. A few of the topics covered in this chapter include: Permanent magnets; Electromagnetic induction; and Mutual inductance. Diagrams and detailed descriptions of concepts are included throughout the chapter to provide users with a comprehensive lesson. Visitors to the site are also encouraged to discuss concepts and topics using the All About Circuits discussion forums (registration with the site is required to post materials).

  12. Computational electronics and electromagnetics

    SciTech Connect

    Shang, C C

    1998-01-01

    The Computational Electronics and Electromagnetics thrust area serves as the focal point for Engineering R and D activities for developing computer-based design and analysis tools. Representative applications include design of particle accelerator cells and beamline components; design of transmission line components; engineering analysis and design of high-power (optical and microwave) components; photonics and optoelectronics circuit design; electromagnetic susceptibility analysis; and antenna synthesis. The FY-97 effort focuses on development and validation of (1) accelerator design codes; (2) 3-D massively parallel, time-dependent EM codes; (3) material models; (4) coupling and application of engineering tools for analysis and design of high-power components; and (5) development of beam control algorithms coupled to beam transport physics codes. These efforts are in association with technology development in the power conversion, nondestructive evaluation, and microtechnology areas. The efforts complement technology development in Lawrence Livermore National programs.

  13. Electromagnetically induced polarization conversion

    NASA Astrophysics Data System (ADS)

    Khanikaev, Alexander B.; Mousavi, S. Hossein; Wu, Chihhui; Dabidian, Nima; Alici, Kamil B.; Shvets, Gennady

    2012-07-01

    Electromagnetically induced transparency and polarization conversion due to interference between two polarization-selective plasmonic resonances coexisting in the same planar metamaterial are studied. The metasurface represents a periodic array of two topologically distinct metamolecules combined on the same substrate: i) monopole antennas connected to wires and supporting a high-Q resonance radiatively coupled to x-polarization, and ii) dipolar antennas supporting a low-Q resonance coupled to y-polarization. We demonstrate that due to the interaction between these modes through a capacitive coupling between the metamolecules, one can observe a circularly-polarized Electromagnetically Induced Transparency (EIT) and thereby achieve an efficient ultra-thin quarter-wave plate.

  14. Spin-Electromagnetic Hydrodynamics

    E-print Network

    Koide, T

    2013-01-01

    The hydrodynamic model including the spin degree of freedom and the electromagnetic field was discussed. In this derivation, we applied electromagnetism for macroscopic medium proposed by Minkowski. For the equation of motion of spin, we assumed that the hydrodynamic equation of the Pauli equation is reproduced when the many-body effect is neglected. The fluid and spin stress tensors induced by the many-body effect were obtained by employing the algebraic positivity of the entropy production in the framework of linear irreversible thermodynamics. In our model, the effect of the spin-magnetic interaction is absorbed into the magnetic polarization so as to satisfy the momentum and angular momentum conservations. We further compared our result with other existing models.

  15. Electromagnetic wave energy converter

    NASA Technical Reports Server (NTRS)

    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.

  16. Electromagnetic Hammer for Metalworking

    NASA Technical Reports Server (NTRS)

    Anderson, S. A.; Brunet, F.; Dowd, A.; Durham, R.; Ezell, J.; Gorr, G.; Hartley, D.; Jackson, F.; Marchand, J.; Macfarlane, W.; Nameth, P.; Okelly, K.; Phillips, H.; Rollo, J.; Rupert, E.; Sykes, H.; Vitrano, E.; Woods, M.

    1986-01-01

    High eddy currents apply pressure for cold-forming. Coil housing constructed for mechanical strength to hold coil against magnetic force, to maintain electrical contact with coil ends, and to maintain insulation between coil turns. Drilled holes placed to facilitate release of bubbles during potting. In contrast with mechanical hammers, electromagnetic hammer requires no dynamic material contact with workpiece; consequently, produces almost no change in metal grain structure.

  17. Banded electromagnetic stator core

    DOEpatents

    Fanning, Alan W. (San Jose, CA); Gonzales, Aaron A. (San Jose, CA); Patel, Mahadeo R. (San Jose, CA); Olich, Eugene E. (Aptos, CA)

    1996-01-01

    A stator core for an electromagnetic pump includes a plurality of circumferentially adjoining groups of flat laminations disposed about a common centerline axis and collectively defining a central bore and a discontinuous outer perimeter, with adjacent groups diverging radially outwardly to form V-shaped gaps. An annular band surrounds the groups and is predeterminedly tensioned to clamp together the laminations, and has a predetermined flexibility in a radial direction to form substantially straight bridge sections between the adjacent groups.

  18. Banded electromagnetic stator core

    DOEpatents

    Fanning, Alan W. (San Jose, CA); Gonzales, Aaron A. (San Jose, CA); Patel, Mahadeo R. (San Jose, CA); Olich, Eugene E. (Aptos, CA)

    1994-01-01

    A stator core for an electromagnetic pump includes a plurality of circumferentially adjoining groups of flat laminations disposed about a common centerline axis and collectively defining a central bore and a discontinuous outer perimeter, with adjacent groups diverging radially outwardly to form V-shaped gaps. An annular band surrounds the groups and is predeterminedly tensioned to clamp together the laminations, and has a predetermined flexibility in a radial direction to form substantially straight bridge sections between the adjacent groups.

  19. Quaternion Gravi-Electromagnetism

    E-print Network

    A. S. Rawat; O. P. S. Negi

    2011-07-05

    Defining the generalized charge, potential, current and generalized fields as complex quantities where real and imaginary parts represent gravitation and electromagnetism respectively, corresponding field equation, equation of motion and other quantum equations are derived in manifestly covariant manner. It has been shown that the field equations are invariant under Lorentz as well as duality transformations. It has been shown that the quaternionic formulation presented here remains invariant under quaternion transformations.

  20. Gravitation and Electromagnetism

    E-print Network

    B. G. Sidharth

    2001-06-16

    The realms of gravitation, belonging to Classical Physics, and Electromagnetism, belonging to the Theory of the Electron and Quantum Mechanics have remained apart as two separate pillars, inspite of a century of effort by Physicists to reconcile them. In this paper it is argued that if we extend ideas of Classical spacetime to include in addition to non integrability non commutavity also, then such a reconcilation is possible.

  1. Fractional Electromagnetic Waves

    E-print Network

    J. F. Gómez; J. J. Rosales; J. J. Bernal; V. I. Tkach; M. Guķa

    2011-08-31

    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.

  2. Ordinary electromagnetic mode instability

    NASA Technical Reports Server (NTRS)

    Cheng, C. Z.

    1974-01-01

    The instability of the ordinary electromagnetic mode propagating perpendicular to an external magnetic field is studied for a single-species plasma with ring velocity distribution. The marginal instability boundaries for both the purely growing mode and the propagating growing modes are calculated from the instability criteria. The dispersion characteristics for various sets of plasma parameters are also given. The typical growth rates are of the order of the cyclotron frequency.

  3. Banded electromagnetic stator core

    DOEpatents

    Fanning, A.W.; Gonzales, A.A.; Patel, M.R.; Olich, E.E.

    1994-04-05

    A stator core for an electromagnetic pump includes a plurality of circumferentially adjoining groups of flat laminations disposed about a common centerline axis and collectively defining a central bore and a discontinuous outer perimeter, with adjacent groups diverging radially outwardly to form V-shaped gaps. An annular band surrounds the groups and is predeterminedly tensioned to clamp together the laminations, and has a predetermined flexibility in a radial direction to form substantially straight bridge sections between the adjacent groups. 5 figures.

  4. Coherent hybrid electromagnetic field imaging

    DOEpatents

    Cooke, Bradly J. (Jemez Springs, NM); Guenther, David C. (Los Alamos, NM)

    2008-08-26

    An apparatus and corresponding method for coherent hybrid electromagnetic field imaging of a target, where an energy source is used to generate a propagating electromagnetic beam, an electromagnetic beam splitting means to split the beam into two or more coherently matched beams of about equal amplitude, and where the spatial and temporal self-coherence between each two or more coherently matched beams is preserved. Two or more differential modulation means are employed to modulate each two or more coherently matched beams with a time-varying polarization, frequency, phase, and amplitude signal. An electromagnetic beam combining means is used to coherently combine said two or more coherently matched beams into a coherent electromagnetic beam. One or more electromagnetic beam controlling means are used for collimating, guiding, or focusing the coherent electromagnetic beam. One or more apertures are used for transmitting and receiving the coherent electromagnetic beam to and from the target. A receiver is used that is capable of square-law detection of the coherent electromagnetic beam. A waveform generator is used that is capable of generation and control of time-varying polarization, frequency, phase, or amplitude modulation waveforms and sequences. A means of synchronizing time varying waveform is used between the energy source and the receiver. Finally, a means of displaying the images created by the interaction of the coherent electromagnetic beam with target is employed.

  5. Electromagnetic field and cosmic censorship

    E-print Network

    Koray Düzta?

    2014-04-09

    We construct a gedanken experiment in which an extremal Kerr black hole interacts with a test electromagnetic field. Using Teukolsky's solutions for electromagnetic perturbations in Kerr spacetime, and the conservation laws imposed by the energy momentum tensor of the electromagnetic field and the Killing vectors of the spacetime, we prove that this interaction cannot convert the black hole into a naked singularity, thus cosmic censorship conjecture is not violated in this case.

  6. Achievable Transverse Cylindrical Electromagnetic Mode

    E-print Network

    R. Chen; X. Li

    2011-06-04

    The system of Maxwell equations with an initial condition in a vacuum is solved in a cylindrical coordinate system. It derives the cylindrical transverse electromagnetic wave mode in which the electric field and magnetic field are not in phase. Such electromagnetic wave can generate and exist in actual application, and there is no violation of the law of conservation of energy during the electromagnetic field interchanges.

  7. Electromagnetic Meissner-Effect Launcher

    NASA Technical Reports Server (NTRS)

    Robertson, Glen A.

    1990-01-01

    Proposed electromagnetic Meissner-effect launching apparatus differs from previous electromagnetic launchers; no need for electromagnet coil on projectile. Result, no need for brush contacts and high-voltage commutation equipment to supply current directly to projectile coil, or for pulse circuitry to induce current in projectile coil if brush contacts not used. Compresses magnetic field surrounding rear surface of projectile, creating gradient of magnetic pressure pushing projectile forward.

  8. Electromagnetism on Anisotropic Fractals

    E-print Network

    Martin Ostoja-Starzewski

    2011-06-08

    We derive basic equations of electromagnetic fields in fractal media which are specified by three indepedent fractal dimensions {\\alpha}_{i} in the respective directions x_{i} (i=1,2,3) of the Cartesian space in which the fractal is embedded. To grasp the generally anisotropic structure of a fractal, we employ the product measure, so that the global forms of governing equations may be cast in forms involving conventional (integer-order) integrals, while the local forms are expressed through partial differential equations with derivatives of integer order but containing coefficients involving the {\\alpha}_{i}'s. First, a formulation based on product measures is shown to satisfy the four basic identities of vector calculus. This allows a generalization of the Green-Gauss and Stokes theorems as well as the charge conservation equation on anisotropic fractals. Then, pursuing the conceptual approach, we derive the Faraday and Amp\\`ere laws for such fractal media, which, along with two auxiliary null-divergence conditions, effectively give the modified Maxwell equations. Proceeding on a separate track, we employ a variational principle for electromagnetic fields, appropriately adapted to fractal media, to independently derive the same forms of these two laws. It is next found that the parabolic (for a conducting medium) and the hyperbolic (for a dielectric medium) equations involve modified gradient operators, while the Poynting vector has the same form as in the non-fractal case. Finally, Maxwell's electromagnetic stress tensor is reformulated for fractal systems. In all the cases, the derived equations for fractal media depend explicitly on fractal dimensions and reduce to conventional forms for continuous media with Euclidean geometries upon setting the dimensions to integers.

  9. Electromagnetic Meissner effect launcher

    NASA Technical Reports Server (NTRS)

    Robertson, Glen A. (inventor)

    1991-01-01

    An electromagnetic projectile launcher provides acceleration of a superconducting projectile through the diamagnetic repulsion of the superconducting projectile. A superconducting layer is provided aft of the projectile, either directly on the projectile or on a platform upon which the projectile is carried, and a traveling magnetic field is caused to propagate along a magnetic field drive coil in which the projectile is disposed. The resulting diamagnetic repulsion between the superconducting projectile and the traveling magnetic field causes the projectile to be propelled along the coil. In one embodiment, a segmented drive coil is used to generate the traveling magnetic field.

  10. Electromagnetic Probes in PHENIX

    E-print Network

    Gabor David

    2006-09-21

    Electromagnetic probes are arguably the most universal tools to study the different physics processes in high energy hadron and heavy ion collisions. In this paper we summarize recent measurements of real and virtual direct photons at central rapidity by the PHENIX experiment at RHIC in p+p, d+Au and Au+Au collisions. We also discuss the impact of the results and the constraints they put on theoretical models. At the end we report on the immediate as well as on the mid-term future of photon measurements at RHIC.

  11. Gravitation and electromagnetism

    E-print Network

    V. P. Dmitriyev

    2002-07-23

    Maxwell's equations comprise both electromagnetic and gravitational fields. The transverse part of the vector potential belongs to magnetism, the longitudinal one is concerned with gravitation. The Coulomb gauge indicates that longitudinal components of the fields propagate instantaneously. The delta-function singularity of the field of the divergence of the vector potential, referred to as the dilatation center, represents an elementary agent of gravitation. Viewing a particle as a source or a scattering center of the point dilatation, the Newton's gravitation law can be reproduced.

  12. Electromagnetic propulsion for spacecraft

    NASA Technical Reports Server (NTRS)

    Myers, Roger M.

    1993-01-01

    Three electromagnetic propulsion technologies, solid propellant pulsed plasma thrusters (PPT), magnetoplasmadynamic (MPD) thrusters, and pulsed inductive thrusters (PIT), were developed for application to auxiliary and primary spacecraft propulsion. Both the PPT and MPD thrusters were flown in space, though only PPT's were used on operational satellites. The performance of operational PPT's is quite poor, providing only approximately 8 percent efficiency at approximately 1000 s specific impulse. However, laboratory PPT's yielding 34 percent efficiency at 2000 s specific impulse were extensively tested, and peak performance levels of 53 percent efficiency at 5170 s specific impulse were demonstrated. MPD thrusters were flown as experiments on the Japanese MS-T4 spacecraft and the Space Shuttle and were qualified for a flight in 1994. The flight MPD thrusters were pulsed, with a peak performance of 22 percent efficiency at 2500 s specific impulse using ammonia propellant. Laboratory MPD thrusters were demonstrated with up to 70 percent efficiency and 700 s specific impulse using lithium propellant. While the PIT thruster has never been flown, recent performance measurements using ammonia and hydrazine propellants are extremely encouraging, reaching 50 percent efficiency for specific impulses between 4000 to 8000 s. The fundamental operating principles, performance measurements, and system level design for the three types of electromagnetic thrusters are reviewed, and available data on flight tests are discussed for the PPT and MPD thrusters.

  13. Electromagnetic Field Penetration Studies

    NASA Technical Reports Server (NTRS)

    Deshpande, M.D.

    2000-01-01

    A numerical method is presented to determine electromagnetic shielding effectiveness of rectangular enclosure with apertures on its wall used for input and output connections, control panels, visual-access windows, ventilation panels, etc. Expressing EM fields in terms of cavity Green's function inside the enclosure and the free space Green's function outside the enclosure, integral equations with aperture tangential electric fields as unknown variables are obtained by enforcing the continuity of tangential electric and magnetic fields across the apertures. Using the Method of Moments, the integral equations are solved for unknown aperture fields. From these aperture fields, the EM field inside a rectangular enclosure due to external electromagnetic sources are determined. Numerical results on electric field shielding of a rectangular cavity with a thin rectangular slot obtained using the present method are compared with the results obtained using simple transmission line technique for code validation. The present technique is applied to determine field penetration inside a Boeing-757 by approximating its passenger cabin as a rectangular cavity filled with a homogeneous medium and its passenger windows by rectangular apertures. Preliminary results for, two windows, one on each side of fuselage were considered. Numerical results for Boeing-757 at frequencies 26 MHz, 171-175 MHz, and 428-432 MHz are presented.

  14. Electromagnetic interaction of metamaterials

    NASA Astrophysics Data System (ADS)

    Canales, Peter R.

    The observation of extraordinary transmission through subwavelength apertures has propelled a great interest in understanding its nature. It defies classical theories of electromagnetic interaction by demanding a closer examination of the surface properties. Traditionally, as surface features become much smaller in size than a single wavelength of interest, the structure is essentially continuous. Any periodic subwavelength corrugation or aperture array should not interact strongly with an incident field and therefore not contribute to any significant transmission through the film. We find that this is not always the case and that we may tune the surface geometry at these scales to affect the overall medium behavior. It is possible that a material may transcend its own natural properties and, in essence, become a metamaterial. The following analysis examines the concepts of metamaterials from a fundamental viewpoint. It does not seek to disrupt classical theories but instead demonstrates their validity to describe a new phenomenon. Several theories have been proposed that offer unique surface interactions as evidence of enhanced transmission. It is proposed that a fundamental Maxwell representation is sufficient in predicting the interaction of an electromagnetic wave with a metamaterial. In particular, a formalism has been developed to analyze enhanced transmission through a metallic grating structure. To experimentally validate this model, a fabrication procedure has been developed that allows for the production of quality thick film structures with subwavelength features. Finally, the analysis of metamaterials looks towards the RF spectrum to demonstrate a novel design to achieve conformal waveguides and antennas.

  15. Distributed computational electromagnetics systems

    SciTech Connect

    Cheng, G.; Hawick, K.A.; Fox, G.C. [Syracuse Univ., NY (United States)] [and othersr

    1995-12-01

    We describe our development of a {open_quotes}real world{close_quotes} electromagnetic application on distributed computing systems. A computational electromagnetics (CEM) simulation for radar cross-section(RCS) modeling of full scale airborne systems has been ported to three networked workstation cluster systems: an IBM RS/6000 cluster with Ethernet connection; a DEC Alpha farm connected by a FDDI-based Gigaswitch; and an ATM-connected SUN IPXs testbed. We used the ScaLAPACK LU solver from Oak Ridge National Laboratory/University of Tennessee in our parallel implementation for solving the dense matrix which forms the computationally intensive kernel of this application, and we have adopted BLACS as the message passing interface in all of our code development to achieve high portability across the three configurations. The performance data from this work is reported, together with timing data from other MPP systems on which we have implemented this application including an Intel iPSC/860 and a CM-5, and which we include for comparison.

  16. Metamaterials beyond electromagnetism

    NASA Astrophysics Data System (ADS)

    Kadic, Muamer; Bückmann, Tiemo; Schittny, Robert; Wegener, Martin

    2013-12-01

    Metamaterials are rationally designed man-made structures composed of functional building blocks that are densely packed into an effective (crystalline) material. While metamaterials are mostly associated with negative refractive indices and invisibility cloaking in electromagnetism or optics, the deceptively simple metamaterial concept also applies to rather different areas such as thermodynamics, classical mechanics (including elastostatics, acoustics, fluid dynamics and elastodynamics), and, in principle, also to quantum mechanics. We review the basic concepts, analogies and differences to electromagnetism, and give an overview on the current state of the art regarding theory and experiment—all from the viewpoint of an experimentalist. This review includes homogeneous metamaterials as well as intentionally inhomogeneous metamaterial architectures designed by coordinate-transformation-based approaches analogous to transformation optics. Examples are laminates, transient thermal cloaks, thermal concentrators and inverters, ‘space-coiling’ metamaterials, anisotropic acoustic metamaterials, acoustic free-space and carpet cloaks, cloaks for gravitational surface waves, auxetic mechanical metamaterials, pentamode metamaterials (‘meta-liquids’), mechanical metamaterials with negative dynamic mass density, negative dynamic bulk modulus, or negative phase velocity, seismic metamaterials, cloaks for flexural waves in thin plates and three-dimensional elastostatic cloaks.

  17. Distributed Computational Electromagnetics Systems Gang Chengy

    E-print Network

    Hawick, Ken

    Distributed Computational Electromagnetics Systems Gang Chengy Kenneth A. Hawicky Gerald Mortensenz Geo rey C. Foxy Abstract We describe our development of a \\real world" electromagnetic application on distributed computing systems. A computational electromagnetics (CEM) simulation for radar cross- section

  18. Health hazards and electromagnetic fields

    Microsoft Academic Search

    T. Saunders

    2003-01-01

    Biological rhythms, physical wellbeing and mental states are dependent on our electrical brainwave system interacting with the extremely weak electromagnetic fields generated by the Earth's telluric and Cosmic radiations. In a single generation, since the evolution of humankind over millions of years, we are exposed to a wide range of powerful, artificially generated electromagnetic radiation which adversely affects the subtle

  19. Electromagnetic Compatibility in Weapon Systems

    Microsoft Academic Search

    Fred J. Nichols

    1964-01-01

    The high density of electrical and electronic equipment in modern weapon systems, the extension of performance limits of both the equipment and the weapon systems and growth in complexity and quantity of systems have greatly aggravated the problem of insuring electromagnetic compatibility. Electromagnetic incompatibility can exist as soon as two or more of the most minor elements of the system

  20. Particle swarm optimization in electromagnetics

    Microsoft Academic Search

    Jacob Robinson; Yahya Rahmat-Samii

    2004-01-01

    The particle swarm optimization (PSO), new to the electromagnetics community, is a robust stochastic evolutionary computation technique based on the movement and intelligence of swarms. This paper introduces a conceptual overview and detailed explanation of the PSO algorithm, as well as how it can be used for electromagnetic optimizations. This paper also presents several results illustrating the swarm behavior in

  1. Electromagnetic neutrino: a short review

    E-print Network

    Alexander I. Studenikin

    2014-11-09

    A short review on selected issues related to the problem of neutrino electromagnetic properties is given. After a flash look at the theoretical basis of neutrino electromagnetic form factors, constraints on neutrino magnetic moments and electric millicharge from terrestrial experiments and astrophysical observations are discussed. We also focus on some recent studies of the problem and on perspectives.

  2. Electromagnetic wave propagation below cutoff

    Microsoft Academic Search

    P. Sprangle; E. Esarey; B. Hafizi; S. E. Harris

    1997-01-01

    Summary form only given, as follows. A small amplitude electromagnetic wave can propagate in a plasma below cutoff in the presence of a high frequency large amplitude wave. This is referred to electromagnetically induced transparency (EIT). We extend the analysis of EIT to include relativistic and collisional effects as well as density gradients. We show that the small amplitude wave

  3. Electromagnetic waves: Propagation and radiation

    Microsoft Academic Search

    F. Nibler

    1975-01-01

    The Maxwell equations of the electromagnetic field are considered along with questions of energy flux and energy transformation, the Poynting vector, and concepts regarding a systematic subdivision of the theory of electricity. In a discussion of electromagnetic waves attention is given to the wave differential equation, plane waves, the Hertz dipole as a prototype of a radiation source, the magnetic

  4. Electromagnetic reactions on light nuclei

    E-print Network

    Sonia Bacca; Saori Pastore

    2014-07-13

    Electromagnetic reactions on light nuclei are fundamental to advance our understanding of nuclear structure and dynamics. The perturbative nature of the electromagnetic probes allows to clearly connect measured cross sections with the calculated structure properties of nuclear targets. We present an overview on recent theoretical ab-initio calculations of electron-scattering and photonuclear reactions involving light nuclei. We encompass both the conventional approach and the novel theoretical framework provided by chiral effective field theories. Because both strong and electromagnetic interactions are involved in the processes under study, comparison with available experimental data provides stringent constraints on both many-body nuclear Hamiltonians and electromagnetic currents. We discuss what we have learned from studies on electromagnetic observables of light nuclei, starting from the deuteron and reaching up to nuclear systems with mass number A=16.

  5. Electromagnetically Clean Solar Arrays

    NASA Technical Reports Server (NTRS)

    Stem, Theodore G.; Kenniston, Anthony E.

    2008-01-01

    The term 'electromagnetically clean solar array' ('EMCSA') refers to a panel that contains a planar array of solar photovoltaic cells and that, in comparison with a functionally equivalent solar-array panel of a type heretofore used on spacecraft, (1) exhibits less electromagnetic interferences to and from other nearby electrical and electronic equipment and (2) can be manufactured at lower cost. The reduction of electromagnetic interferences is effected through a combination of (1) electrically conductive, electrically grounded shielding and (2) reduction of areas of current loops (in order to reduce magnetic moments). The reduction of cost is effected by designing the array to be fabricated as a more nearly unitary structure, using fewer components and fewer process steps. Although EMCSAs were conceived primarily for use on spacecraft they are also potentially advantageous for terrestrial applications in which there are requirements to limit electromagnetic interference. In a conventional solar panel of the type meant to be supplanted by an EMCSA panel, the wiring is normally located on the back side, separated from the cells, thereby giving rise to current loops having significant areas and, consequently, significant magnetic moments. Current-loop geometries are chosen in an effort to balance opposing magnetic moments to limit far-0field magnetic interactions, but the relatively large distances separating current loops makes full cancellation of magnetic fields problematic. The panel is assembled from bare photovoltaic cells by means of multiple sensitive process steps that contribute significantly to cost, especially if electomagnetic cleanliness is desired. The steps include applying a cover glass and electrical-interconnect-cell (CIC) sub-assemble, connecting the CIC subassemblies into strings of series-connected cells, laying down and adhesively bonding the strings onto a panel structure that has been made in a separate multi-step process, and mounting the wiring on the back of the panel. Each step increases the potential for occurrence of latent defects, loss of process control, and attrition of components. An EMCSA panel includes an integral cover made from a transparent material. The silicone cover supplants the individual cover glasses on the cells and serves as an additional unitary structural support that offers the advantage, relative to glass, of the robust, forgiving nature of the silcone material. The cover contains pockets that hold the solar cells in place during the lamination process. The cover is coated with indium tin oxide to make its surface electrically conductive, so that it serves as a contiguous, electrically grounded shield over the entire panel surface. The cells are mounted in proximity to metallic printed wiring. The painted-wiring layer comprises metal-film traces on a sheet of Kapton (or equivalent) polyimide. The traces include contact pads on one side of the sheet for interconnecting the cells. Return leads are on the opposite side of the sheet, positioned to form the return currents substantially as mirror images of, and in proximity to, the cell sheet currents, thereby minimizing magnetic moments. The printed-wiring arrangement mimics the back-wiring arrangement of conventional solar arrays, but the current-loop areas and the resulting magnetic moments are much smaller because the return-current paths are much closer to the solar-cell sheet currents. The contact pads are prepared with solder fo electrical and mechanical bonding to the cells. The pocketed cover/shield, the solar cells, the printed-wiring layer, an electrical bonding agent, a mechanical-bonding agent, a composite structural front-side face sheet, an aluminum honeycomb core, and a composite back-side face sheet are all assembled, then contact pads are soldered to the cells and the agents are cured in a single lamination process.

  6. Pulsed electromagnetic gas acceleration

    NASA Technical Reports Server (NTRS)

    Jahn, R. G.; Vonjaskowsky, W. F.; Clark, K. E.

    1971-01-01

    Experimental data were combined with one-dimensional conservation relations to yield information on the energy deposition ratio in a parallel-plate accelerator, where the downstream flow was confined to a constant area channel. Approximately 70% of the total input power was detected in the exhaust flow, of which only about 20% appeared as directed kinetic energy, thus implying that a downstream expansion to convert chamber enthalpy into kinetic energy must be an important aspect of conventional high power MPD arcs. Spectroscopic experiments on a quasi-steady MPD argon accelerator verified the presence of A(III) and the absence of A(I), and indicated an azimuthal structure in the jet related to the mass injection locations. Measurements of pressure in the arc chamber and impact pressure in the exhaust jet using a piezocrystal backed by a Plexiglas rod were in good agreement with the electromagnetic thrust model.

  7. Electromagnetic scattering theory

    NASA Technical Reports Server (NTRS)

    Bird, J. F.; Farrell, R. A.

    1986-01-01

    Electromagnetic scattering theory is discussed with emphasis on the general stochastic variational principle (SVP) and its applications. The stochastic version of the Schwinger-type variational principle is presented, and explicit expressions for its integrals are considered. Results are summarized for scalar wave scattering from a classic rough-surface model and for vector wave scattering from a random dielectric-body model. Also considered are the selection of trial functions and the variational improvement of the Kirchhoff short-wave approximation appropriate to large size-parameters. Other applications of vector field theory discussed include a general vision theory and the analysis of hydromagnetism induced by ocean motion across the geomagnetic field. Levitational force-torque in the magnetic suspension of the disturbance compensation system (DISCOS), now deployed in NOVA satellites, is also analyzed using the developed theory.

  8. Electromagnetically Induced Transparency Spectroscopy

    E-print Network

    Eliam, Asaf; Shapiro, Moshe

    2012-01-01

    We propose a method based on the Electromagnetically Induced Transparency (EIT) phenomenon for the detection of molecules which exist as a small minority in the presence of a majority of absorbers. The EIT effect we employ effectively eliminates the absorption of the majority species in the spectral region where it overlaps with the absorption of the minority species. The method can also be used to enhance local-modes transitions which overlap spectrally with a background of other local-modes transitions of the same molecule. The general theory is applied to the case of sparse and congested background spectra within the same molecule and to the recording of the spectra of isotopomers (of Chlorine and Methanol) that are in minority relative to other isotopomers which constitute the majority of molecules present.

  9. Electromagnetically Induced Transparency Spectroscopy

    E-print Network

    Asaf Eliam; Evgeny A. Shapiro; Moshe Shapiro

    2012-01-03

    We propose a method based on the Electromagnetically Induced Transparency (EIT) phenomenon for the detection of molecules which exist as a small minority in the presence of a majority of absorbers. The EIT effect we employ effectively eliminates the absorption of the majority species in the spectral region where it overlaps with the absorption of the minority species. The method can also be used to enhance local-modes transitions which overlap spectrally with a background of other local-modes transitions of the same molecule. The general theory is applied to the case of sparse and congested background spectra within the same molecule and to the recording of the spectra of isotopomers (of Chlorine and Methanol) that are in minority relative to other isotopomers which constitute the majority of molecules present.

  10. Causal electromagnetic interaction equations

    SciTech Connect

    Zinoviev, Yury M. [Steklov Mathematical Institute, Gubkin Street 8, 119991, Moscow (Russian Federation)

    2011-02-15

    For the electromagnetic interaction of two particles the relativistic causal quantum mechanics equations are proposed. These equations are solved for the case when the second particle moves freely. The initial wave functions are supposed to be smooth and rapidly decreasing at the infinity. This condition is important for the convergence of the integrals similar to the integrals of quantum electrodynamics. We also consider the singular initial wave functions in the particular case when the second particle mass is equal to zero. The discrete energy spectrum of the first particle wave function is defined by the initial wave function of the free-moving second particle. Choosing the initial wave functions of the free-moving second particle it is possible to obtain a practically arbitrary discrete energy spectrum.

  11. The Electromagnetic Spectrum

    NSDL National Science Digital Library

    2012-08-03

    In this lesson, students are introduced to the electromagnetic spectrum. They observe a demonstration of the visible light spectrum created by a flashlight and a prism, complete an activity sheet where they identify the wavelength that is involved in technologies used in their communities, and learn about satellite sensors that remotely sense data. Student worksheets, a data sheet, answer keys, and Web links are included. This is Lesson 3 in Understanding Light, part of IMAGERS, Interactive Media Adventures for Grade School Education using Remote Sensing. The website provides hands-on activities in the classroom supporting the science content in two interactive media books, The Adventures of Echo the Bat and Amelia the Pigeon.

  12. ELECTROMAGNETIC FIELD EFFECTS IN EXPLOSIVES

    SciTech Connect

    Tasker, D. G.; Whitley, V. H. [MS J566, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Lee, R. J. [Lndian Head Division, Naval Surface Warfare Center, Indian Head, MD 20640 (United States)

    2009-12-28

    Present and previous research on the effects of electromagnetic fields on the initiation and detonation of explosives and the electromagnetic properties of explosives are reviewed. Among the topics related to detonating explosives are: enhancement of performance; and control of initiation and growth of reaction. Two series of experiments were performed to determine the effects of 1-T magnetic fields on explosive initiation and growth in the modified gap test and on the propagation of explosively generated plasma into air. The results have implications for the control of reactions in explosives and for the use of electromagnetic particle velocity gauges.

  13. Electromagnetic neutrinos in terrestrial experiments and astrophysics

    E-print Network

    Carlo Giunti; Konstantin A. Kouzakov; Yu-Feng Li; Alexey V. Lokhov; Alexander I. Studenikin; Shun Zhou

    2015-06-17

    An overview of neutrino electromagnetic properties, which open a door to the new physics beyond the Standard Model, is given. The effects of neutrino electromagnetic interactions both in terrestrial experiments and in astrophysical environments are discussed. The experimental bounds on neutrino electromagnetic characteristics are summarized. Future astrophysical probes of electromagnetic neutrinos are outlined.

  14. PHYSICS 417. Electromagnetism. Lecturer: Tim Gorringe.

    E-print Network

    MacAdam, Keith

    PHYSICS 417. Electromagnetism. Lecturer: Tim Gorringe. Office: CP273. Phone: 257-8740. Textbook: Electromagnetic Fields, R. Wangsness, 2nd Ed. Web page www.pa.uky.edu/gorringe/phy417/index.html Class hours: MWF-semester sequence on electromagnetic theory. 1 Course Objectives. The electromagnetic field binds electrons

  15. PHYSICS 416. Electromagnetism. Lecturer: Tim Gorringe.

    E-print Network

    MacAdam, Keith

    PHYSICS 416. Electromagnetism. Lecturer: Tim Gorringe. Office: CP 273. Phone: 257-8740. Textbook: Electromagnetic Fields, R. Wangsness, 2nd Ed. Web page www.pa.uky.edu/gorringe/phy416/index.html Class hours: MWF-semester sequence on electromagnetic theory. 1 416/417 Course Objectives. The electromagnetic field binds electrons

  16. Electromagnetic nature of dark energy

    Microsoft Academic Search

    Jose Beltran Jimenez; Antonio L. Maroto

    2009-01-01

    Out of the four components of the electromagnetic field, Maxwell's theory\\u000aonly contains two physical degrees of freedom. However, in an expanding\\u000auniverse, consistently eliminating one of the \\

  17. Electromagnetically induced transparency by NMR

    E-print Network

    Son, HyungBin, 1981-

    2004-01-01

    Electromagnetically Induced Transparency (EIT) is a quantum nonlinear optical interference effect in which light at a certain frequency makes normally opaque atomic systems transparent to light at another frequency. Recent ...

  18. Electromagnetic recording and playback device

    E-print Network

    Chavez, Dylan, 1981-

    2004-01-01

    The purpose of this thesis is the design and manufacture of an electromagnetic recording and playback device. The device was designed to record information onto a steel wire which can replay the signal. The device is of ...

  19. Electromagnetic Signals from Bacterial DNA

    E-print Network

    A. Widom; J. Swain; Y. N. Srivastava; S. Sivasubramanian

    2012-02-09

    Chemical reactions can be induced at a distance due to the propagation of electromagnetic signals during intermediate chemical stages. Although is is well known at optical frequencies, e.g. photosynthetic reactions, electromagnetic signals hold true for muck lower frequencies. In E. coli bacteria such electromagnetic signals can be generated by electric transitions between energy levels describing electrons moving around DNA loops. The electromagnetic signals between different bacteria within a community is a "wireless" version of intercellular communication found in bacterial communities connected by "nanowires". The wireless broadcasts can in principle be of both the AM and FM variety due to the magnetic flux periodicity in electron energy spectra in bacterial DNA orbital motions.

  20. Electromagnetic Implosion Using a Lens

    Microsoft Academic Search

    Carl E. Baum

    This paper considers the use of dielectric lenses for concentrating a fast pulse on a target (an electromagnetic implosion). There are similarities to and differences from the prolate-spheroidal-reflector case.

  1. SOLAR NANTENNA ELECTROMAGNETIC COLLECTORS

    SciTech Connect

    Steven D. Novack; Dale K. Kotter; Dennis Slafer; Patrick Pinhero

    2008-08-01

    This research explores a new efficient approach for producing electricity from the abundant energy of the sun. A nanoantenna electromagnetic collector (NEC) has been designed, prototyped, and tested. Proof of concept has been validated. The device targets mid-infrared wavelengths where conventional photovoltaic (PV) solar cells do not respond but is abundant in solar energy. The initial concept of designing NEC antennas was based on scaling of radio frequency antenna theory. This approach has proven unsuccessful by many due to not fully understanding and accounting for the optical behavior of materials in the THz region. Also until recent years the nanofabrication methods were not available to fabricate the optical antenna elements. We have addressed and overcome both technology barriers. Several factors were critical in successful implementation of NEC including: 1) frequency-dependent modeling of antenna elements, 2) selection of materials with proper THz properties and 3) novel manufacturing methods that enable economical large-scale manufacturing. The work represents an important step toward the ultimate realization of a low-cost device that will collect as well as convert this radiation into electricity, which will lead to a wide spectrum, high conversion efficiency, and low cost solution to complement conventional PVs.

  2. Electromagnetic Calorimeter for HADES

    E-print Network

    W. Czyzycki; E. Epple; L. Fabbietti; M. Golubeva; F. Guber; A. Ivashkin; M. Kajetanowicz; A. Krasa; F. Krizek; A. Kugler; K. Lapidus; E. Lisowski; J. Pietraszko; A. Reshetin; P. Salabura; Y. Sobolev; J. Stanislav; P. Tlusty; T. Torrieri; M. Traxler

    2011-11-28

    We propose to build the Electromagnetic calorimeter for the HADES di-lepton spectrometer. It will enable to measure the data on neutral meson production from nucleus-nucleus collisions, which are essential for interpretation of dilepton data, but are unknown in the energy range of planned experiments (2-10 GeV per nucleon). The calorimeter will improve the electron-hadron separation, and will be used for detection of photons from strange resonances in elementary and HI reactions. Detailed description of the detector layout, the support structure, the electronic readout and its performance studied via Monte Carlo simulations and series of dedicated test experiments is presented. The device will cover the total area of about 8 m^2 at polar angles between 12 and 45 degrees with almost full azimuthal coverage. The photon and electron energy resolution achieved in test experiments amounts to 5-6%/sqrt(E[GeV]) which is sufficient for the eta meson reconstruction with S/B ratio of 0.4% in Ni+Ni collisions at 8 AGeV. A purity of the identified leptons after the hadron rejection, resulting from simulations based on the test measurements, is better than 80% at momenta above 500 MeV/c, where time-of-flight cannot be used.

  3. Electromagnetism of Bacterial Growth

    NASA Astrophysics Data System (ADS)

    Ainiwaer, Ailiyasi

    2011-10-01

    There has been increasing concern from the public about personal health due to the significant rise in the daily use of electrical devices such as cell phones, radios, computers, GPS, video games and television. All of these devices create electromagnetic (EM) fields, which are simply magnetic and electric fields surrounding the appliances that simultaneously affect the human bio-system. Although these can affect the human system, obstacles can easily shield or weaken the electrical fields; however, magnetic fields cannot be weakened and can pass through walls, human bodies and most other objects. The present study was conducted to examine the possible effects of bacteria when exposed to magnetic fields. The results indicate that a strong causal relationship is not clear, since different magnetic fields affect the bacteria differently, with some causing an increase in bacterial cells, and others causing a decrease in the same cells. This phenomenon has yet to be explained, but the current study attempts to offer a mathematical explanation for this occurrence. The researchers added cultures to the magnetic fields to examine any effects to ion transportation. Researchers discovered ions such as potassium and sodium are affected by the magnetic field. A formula is presented in the analysis section to explain this effect.

  4. Electromagnetic Precursors of Volcanic Activity

    Microsoft Academic Search

    A. Revil; V. Naudet

    2002-01-01

    Considering a buried thermo-mechanical source associated with a magmatic intrusion, thermo-poroelasticity theory predicts the upsurge of temperature-pressure (T-P) soli- tary waves toward the ground surface. We couple electromagnetic theory and thermo- poroelasticity to look at the electromagnetic signature, at the ground surface, of the formation and ascent of these T-P solitary waves. The coupling is due to the electroki- netic

  5. Black Hole Thermodynamics and Electromagnetism

    E-print Network

    Burra G. Sidharth

    2005-07-15

    We show a strong parallel between the Hawking, Beckenstein black hole Thermodynamics and electromagnetism: When the gravitational coupling constant transform into the electromagnetic coupling constant, the Schwarzchild radius, the Beckenstein temperature, the Beckenstein decay time and the Planck mass transform to respectively the Compton wavelength, the Hagedorn temperature, the Compton time and a typical elementary particle mass. The reasons underlying this parallalism are then discussed in detail.

  6. Electromagnetic Effects in SDF Explosions

    Microsoft Academic Search

    H Reichenbach; P Neuwald; A L Kuhl

    2010-01-01

    The notion of high ion and electron concentrations in the detonation of aluminized explosive mixtures has aroused some interest in electro-magnetic effects that the SDF charges might generate when detonated. Motivated by this interest we have started to investigate whether significant electro-magnetic effects show up in our small-scale experiments. However, the design of instrumentation for this purpose is far from

  7. Resolution in Electromagnetic Prospecting

    NASA Astrophysics Data System (ADS)

    Aldridge, D. F.; Bartel, L. C.; Knox, H. A.; Schramm, K. A.

    2014-12-01

    Low-frequency electromagnetic (EM) signals are commonly used in geophysical exploration of the shallow subsurface. Sensitivity to conductivity implies they are particularly useful for inferring fluid content of porous media. However, low-frequency EM wavefields are diffusive, and have significantly larger wavelengths compared to seismic signals of equal frequency. The wavelength of a 30 Hz sinusoid propagating with seismic velocity 3000 m/s is 100 m, whereas an analogous EM signal diffusing through a conductive body of 0.1 S/m (clayey shale) has wavelength 1825 m. The larger wavelength has implications for resolution of the EM prospecting method. We are investigating resolving power of the EM method via theoretical and numerical experiments. Normal incidence plane wave reflection/transmission by a thin geologic bed is amenable to analytic solution. Responses are calculated for beds that are conductive or resistive relative to the host rock. Preliminary results indicate the classic seismic resolution/detection limit of bed thickness ~1/8 wavelength is not achieved. EM responses for point or line current sources recorded by general acquisition geometries are calculated with a 3D finite-difference algorithm. These exhibit greater variability which may allow inference of bed thickness. We also examine composite responses of two point scatterers with separation when illuminated by an incident EM field. This is analogous to the Rayleigh resolution problem of estimating angular separation between two light sources. The First Born Approximation implies that perturbations in permittivity, permeability, and conductivity have different scattering patterns, which may be indicators of EM medium properties. Sandia National Laboratories is a multi-program 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.

  8. Statistical Properties of Electromagnetic Environment in Wireless Networks, Intra-Network Electromagnetic Compatibility and Safety

    E-print Network

    Loyka, Sergey

    Statistical Properties of Electromagnetic Environment in Wireless Networks, Intra-Network Electromagnetic Compatibility and Safety Vladimir Mordachev Belorussian State University of Informatics and Radioelectronics (BSUIR) Electromagnetic Compatibility Laboratory 6, P.Brovki st., Minsk 220013, Belarus E

  9. Dipole-Induced Electromagnetic Transparency

    E-print Network

    Raiju Puthumpally-Joseph; Maxim Sukharev; Osman Atabek; Eric Charron

    2014-09-22

    We determine the optical response of a thin and dense layer of interacting quantum emitters. We show that in such a dense system, the Lorentz redshift and the associated interaction broadening can be used to control the transmission and reflection spectra. In the presence of overlapping resonances, a Dipole-Induced Electromagnetic Transparency (DIET) regime, similar to Electromagnetically Induced Transparency (EIT), may be achieved. DIET relies on destructive interference between the electromagnetic waves emitted by quantum emitters. Carefully tuning material parameters allows to achieve narrow transmission windows in otherwise completely opaque media. We analyze in details this coherent and collective effect using a generalized Lorentz model and show how it can be controlled. Several potential applications of the phenomenon, such as slow light, are proposed.

  10. Electromagnetic contributions to pseudoscalar masses

    E-print Network

    S. Basak; A. Bazavov; C. Bernard; C. DeTar; E. Freeland; W. Freeman; J. Foley; Steven Gottlieb; U. M. Heller; J. E. Hetrick; J. Laiho; L. Levkova; M. Oktay; J. Osborn; R. L. Sugar; A. Torok; D. Toussaint; R. S. Van de Water; R. Zhou

    2013-01-30

    We report on the calculation by the MILC Collaboration of the electromagnetic effects on kaon and pion masses. These masses are computed in QCD with dynamical (asqtad staggered) quarks plus quenched photons at three lattice spacings varying from 0.12 to 0.06 fm. The masses are fit to staggered chiral perturbation theory with NLO electromagnetic terms, as well as analytic terms at higher order. We extrapolate the results to physical light-quark masses and to the continuum limit. At the current stage of the analysis, most, but not all, of the systematic errors have been estimated. The main goal is the comparison of kaon electromagnetic splittings to those of the pion, i.e., an evaluation of the corrections to "Dashen's theorem." This in turn will allow us to significantly reduce the systematic errors in our determination of m_u/m_d.

  11. Experimental Study Of Electromagnetic Missiles

    NASA Astrophysics Data System (ADS)

    Shen, Hao-Ming

    1988-05-01

    The purpose of the experiment is to demonstrate missile-like electromagnetic pulses. More specifically, this is a program to build and test devices capable of launching electromagnetic missiles. I Because a missile-like electro-magnetic pulse (EMP) involves transients with rise times under 100 ps, the measurement of short pulses is essential. The program must measure the EMP accurately enough to confirm the slow decay of the energy and provide the means for improving the design of the EM-missile launcher. After adopting the newly designed transmitting antenna (V-conical antenna) and receiving antenna Pantenna), the entire system is found to work properly up to 10 GHz. The preliminary results show that the energy of an ENV launched from an EM-missile launcher does have the property of slow decay.

  12. Un-renormalized classical electromagnetism

    SciTech Connect

    Ibison, Michael [Institute for Advanced Studies at Austin, 4030 West Braker Lane, Suite 300, Austin, TX 78759 (United States)]. E-mail: ibison@earthtech.org

    2006-02-15

    This paper follows in the tradition of direct-action versions of electromagnetism having the aim of avoiding a balance of infinities wherein a mechanical mass offsets an infinite electromagnetic mass so as to arrive at a finite observed value. However, the direct-action approach ultimately failed in that respect because its initial exclusion of self-action was later found to be untenable in the relativistic domain. Pursing the same end, this paper examines instead a version of electromagnetism wherein mechanical action is excluded and self-action is retained. It is shown that the resulting theory is effectively interacting due to the presence of infinite forces. A vehicle for the investigation is a pair of classical point charges in a positronium-like arrangement for which the orbits are found to be self-sustaining and naturally quantized.

  13. Electromagnetic corrections to baryon masses

    SciTech Connect

    Durand, Loyal; Ha, Phuoc [Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Department of Physics and Astronomy, Indiana University South Bend, South Bend Indiana 46634 (United States); Institute of Physics and Electronics, Vietnamese Academy of Science and Technology, 10 Dao Tan, Ba Dinh, Hanoi (Viet Nam)

    2005-04-01

    We analyze the electromagnetic contributions to the octet and decuplet baryon masses using the heavy-baryon approximation in chiral effective field theory and methods we developed in earlier analyses of the baryon masses and magnetic moments. Our methods connect simply to Morpurgo's general parametrization of the electromagnetic contributions and to semirelativistic quark models. Our calculations are carried out including the one-loop mesonic corrections to the basic electromagnetic interactions, so to two loops overall. We find that to this order in the chiral loop expansion there are no three-body contributions. The Coleman-Glashow relation and other sum rules derived in quark models with only two-body terms therefore continue to hold, and violations involve at least three-loop processes and can be expected to be quite small. We present the complete formal results and some estimates of the matrix elements here. Numerical calculations will be presented separately.

  14. Electromagnetic Gun With Commutated Coils

    NASA Technical Reports Server (NTRS)

    Elliott, David G.

    1991-01-01

    Proposed electromagnetic gun includes electromagnet coil, turns of which commutated in sequence along barrel. Electrical current fed to two armatures by brushes sliding on bus bars in barrel. Interaction between armature currents and magnetic field from coil produces force accelerating armature, which in turn, pushes on projectile. Commutation scheme chosen so magnetic field approximately coincides and moves with cylindrical region defined by armatures. Scheme has disadvantage of complexity, but in return, enables designer to increase driving magnetic field without increasing armature current. Attainable muzzle velocity increased substantially.

  15. Electromagnetic Models of Extragalactic Jets

    SciTech Connect

    Lisanti, M.; Blandford, R.; /KIPAC, Menlo Park

    2007-10-22

    Relativistic jets may be confined by large-scale, anisotropic electromagnetic stresses that balance isotropic particle pressure and disordered magnetic field. A class of axisymmetric equilibrium jet models will be described and their radiative properties outlined under simple assumptions. The partition of the jet power between electromagnetic and mechanical forms and the comoving energy density between particles and magnetic field will be discussed. Current carrying jets may be recognized by their polarization patterns. Progress and prospects for measuring this using VLBI and GLAST observations will be summarized.

  16. Electromagnetic radiation by gravitating bodies

    E-print Network

    Iwo Bialynicki-Birula; Zofia Bialynicka-Birula

    2008-05-06

    Gravitating bodies in motion, regardless of their constitution, always produce electromagnetic radiation in the form of photon pairs. This phenomenon is an analog of the radiation caused by the motion of dielectric (or magnetic) bodies. It is a member of a wide class of phenomena named dynamical Casimir effects, and it may be viewed as the squeezing of the electromagnetic vacuum. Production of photon pairs is a purely quantum-mechanical effect. Unfortunately, as we show, the emitted radiation is extremely weak as compared to radiation produced by other mechanisms.

  17. From the electromagnetic pulse to high-power electromagnetics

    NASA Astrophysics Data System (ADS)

    Baum, Carl E.

    1992-06-01

    This paper updates the published literature of the late 1970's concerning the development of requisite technology for the nuclear EMP. EMP has impacted a set of related areas that can be collectively referred to as high-power electromagnetics. This includes high-power microwaves, direct-strike lightning, and some aspects of transient radar.

  18. A Class of Stationary Electromagnetic Vacuum Fields

    E-print Network

    Israel, Werner; Wilson, Gordon A.

    1972-01-10

    It is shown how a new class of stationary electromagnetic vacuum fields can be generated from solutions of Laplace's equation. These fields are a stationary generalization of the static electromagnetic vacuum fields of Weyl, Majumdar, and Papapetrou...

  19. Electromagnetic formation flight dipole solution planning

    E-print Network

    Schweighart, Samuel A. (Samuel Adam), 1977-

    2005-01-01

    Electromagnetic Formation Flight (EMFF) describes the concept of using electromagnets (coupled with reaction wheels) to provide all of the necessary forces and torques needed to maintain a satellite's relative position and ...

  20. Parallel Processing in High Performance Computational Electromagnetics

    E-print Network

    Barthelat, Francois

    Parallel Processing in High Performance Computational Electromagnetics David Abraham, under the supervision of Professor Dennis D. Giannacopoulos Department of Electrical and Computer Engineering, Mc such as finite element analysis, have had much success performing electromagnetic modelling and simulation

  1. Quantized electromagnetic tornado in pulsar vacuum gap

    E-print Network

    Fominov, Yakov

    Quantized electromagnetic tornado in pulsar vacuum gap Giant pulses Regular radiation 1937+21 By A of the electromagnetic tornado. The quasi-classical and exact quantization of this rotation is possible. 9 #12;Possible

  2. Project no. 516369 Electromagnetic compatibility between rolling stock and

    E-print Network

    Paris-Sud XI, Université de

    Project no. 516369 Electromagnetic compatibility between rolling stock and rail are recalled in this section. Electromagnetic compatibility: The ability of an equipment or system to function satisfactorily in its electromagnetic environment without introducing intolerable electromagnetic disturbances

  3. The electromagnetic spectrum : waves of energy

    NSDL National Science Digital Library

    Tracy Coulson

    2002-01-01

    In this lesson, students will (1) understand that the sun energy is transferred to Earth by electromagnetic waves, which are transverse waves, (2) understand that there are eight main types of electromagnetic waves, classified on the electromagnetic spectrum according to their wavelengths, and (3) understand how each of the types of electromagnetic radiation is used or found in our everyday lives. This would be a suitable activity for small groups.

  4. Electromagnetic effects on geodesic acoustic modes

    SciTech Connect

    Bashir, M. F., E-mail: frazbashir@yahoo.com [Salam Chair in Physics, G. C. University Lahore, Katchery Road, Lahore 54000 (Pakistan); Department of Physics, G. C. University Lahore, Katchery Road, Lahore 54000 (Pakistan); Smolyakov, A. I. [University of Saskatchewan, 116 Science Place, Saskatoon S7N 5E2 (Canada); Institute of Tokamak Physics, NRC “Kurchatov Institute,” 123182 Moscow (Russian Federation); Elfimov, A. G. [Institute of Physics, University of Sćo Paulo, Sćo Paulo 05508-090 (Brazil); Melnikov, A. V. [Institute of Tokamak Physics, NRC “Kurchatov Institute,” 123182 Moscow (Russian Federation); National Research Nuclear University MEPhI, 115409, Moscow (Russian Federation); Murtaza, G. [Visiting Professor, Department of Physics, Quaid-e-Azam University, Islamabad (Pakistan)

    2014-08-15

    By using the full electromagnetic drift kinetic equations for electrons and ions, the general dispersion relation for geodesic acoustic modes (GAMs) is derived incorporating the electromagnetic effects. It is shown that m?=?1 harmonic of the GAM mode has a finite electromagnetic component. The electromagnetic corrections appear for finite values of the radial wave numbers and modify the GAM frequency. The effects of plasma pressure ?{sub e}, the safety factor q, and the temperature ratio ? on GAM dispersion are analyzed.

  5. Why Study Electromagnetics: The First Unit in an Undergraduate Electromagnetics Course

    E-print Network

    Taflove, Allen

    1 Why Study Electromagnetics: The First Unit in an Undergraduate Electromagnetics Course Allen unification of electric and magnetic fields predicting electromagnetic wave phenomena which Nobel Laureate: "Of what relevance is the study of electromagnetics to our modern society?" The goal of this unit

  6. STIMULATED ELECTROMAGNETIC EMISSIONS BY HIGH-FREQUENCY ELECTROMAGNETIC PUMPING OF THE

    E-print Network

    STIMULATED ELECTROMAGNETIC EMISSIONS BY HIGH-FREQUENCY ELECTROMAGNETIC PUMPING OF THE IONOSPHERIC.S.A. Abstract. A high frequency electromagnetic pump wave transmitted into the ionospheric plasma from the ground can stimulate electromagnetic radiation with frequencies around that of the ionospher- ically

  7. Electromagnetic nature of dark energy

    Microsoft Academic Search

    Jose Beltra“n Jime“nez; Antonio L. Maroto

    2010-01-01

    Out of the four components of the electromagnetic field, Maxwell’s theory only contains two physical degrees of freedom. However, in an expanding universe, consistently eliminating one of the “unphysical” states in the covariant (Gupta-Bleuler) formalism turns out to be difficult to realize. In this work we explore the possibility of quantization without subsidiary conditions. This implies that the theory would

  8. Electromagnetic nature of dark energy

    Microsoft Academic Search

    Jose Beltrįn Jiménez; Antonio L. Maroto

    2010-01-01

    Out of the four components of the electromagnetic field, Maxwell's theory only contains two physical degrees of freedom. However, in an expanding universe, consistently eliminating one of the ``unphysical'' states in the covariant (Gupta-Bleuler) formalism turns out to be difficult to realize. In this work we explore the possibility of quantization without subsidiary conditions. This implies that the theory would

  9. Current-driven electromagnetic modes

    Microsoft Academic Search

    J. L. Sperling; D. K. Bhadra

    1979-01-01

    The dispersion relation for current-driven electromagnetic instabilities in an inhomogeneous slab geometry is derived and analyzed. It is shown that current in the direction of the equilibrium magnetic field, as well as transverse current gradients, can strongly modify the drift-Alfven dispersion relation as given by Kadomtsev (1965). If the perpendicular wavelength is much larger than the ion gyroradius there can

  10. Electromagnetic forces in photonic crystals

    Microsoft Academic Search

    M. I. Antonoyiannakis; J. B. Pendry

    1999-01-01

    We have developed a general methodology for computing electromagnetic (EM) fields and forces in matter, based on solving the macroscopic Maxwell's equations numerically in real space and adopting the time-averaged Maxwell stress tensor formalism. We can treat both dielectric and metallic systems characterized by a local frequency-dependent dielectric function, and of any size and geometry in principle. In this paper,

  11. Explanations, Education, and Electromagnetic Fields.

    ERIC Educational Resources Information Center

    Friedman, Sharon M.

    Explaining complex scientific and environmental subjects in the mass media is difficult to do, particularly under such constraints as short deadlines and lack of space or time. When a scientific controversy and human health risk are involved, this becomes an even harder task to accomplish. The subject of electromagnetic fields (EMF) involves…

  12. Electromagnetic Excitation of Acoustic Biosensors

    Microsoft Academic Search

    A. C. Stevenson; B. Araya-Kleinsteuber; J. Lee; C. R. Lowe

    2007-01-01

    One of the problems associated with the acoustic biosensor format, is the isolation of the electrical connections, from the liquid test sample. In this paper, we describe our search for an electromagnetic coupling solution, how we modified it for acoustic biosensors, and some of the physical characteristics that we did not anticipate: We began by reviewing the formal descriptions of

  13. Electromagnetic Design With Transformation Optics

    Microsoft Academic Search

    Nathan B. Kundtz; David R. Smith; John B. Pendry

    2011-01-01

    Transformation optics is an emerging technique for the design of advanced electromagnetic media. Transfor- mation optical devices exploit the form invariance of Maxwell's equations, allowing geometry to play the dominant role in the design process rather than traditional wave or ray optics. The use of coordinate transformations vastly eases the burden of design for a large class of devices, though

  14. Electromagnetism of rotating conductors revisited

    Microsoft Academic Search

    Dragan V. Redzic

    2002-01-01

    The charge distribution and electromagnetic fields in a rotating, charged conductor under stationary conditions are investigated, assuming that the electrons are at rest relative to the conductor. The basic equations are found, referred to the inertial rest frame of the rotational axis, in the relativistic case, and applied to the case of a cylindrical conductor. The results obtained are compared

  15. The Electromagnetic Spectrum: Resonating Atmosphere

    NSDL National Science Digital Library

    Using a paper and tape device, students experience how atoms and molecules of gas in Earth’s atmosphere absorb electromagnetic energy through resonance. This activity is part of Unit 2 in the Space Based Astronomy guide that contains background information, worksheets, assessments, extensions, and standards.

  16. The kaon electromagnetic form factor

    E-print Network

    J. Lowe; M. D. Scadron

    2005-09-28

    We use recent data on K^+ -> pi^+ e^+ e^-, together with known values for the pion form factor, to derive experimental values for the kaon electromagnetic form factor for 0 < q^2 < 0.125 (GeV/c)^2. The results are then compared with the predictions of the Vector Meson Dominance model, which gives a good fit to the experimental results.

  17. Proposed electromagnetic wave energy converter

    NASA Technical Reports Server (NTRS)

    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.

  18. Multifunction Electromagnetic Radiating System (MERS)

    Microsoft Academic Search

    J. W. Eadie; S. Hart; D. Charette; D. Jancic

    1998-01-01

    As part of the Navy's Integrated Topside Design effort, the Science and Technology Community initiated several technology demonstrations for the development of reduced signature sensors to produce a low-observable surface combatant. The objective of the Multifunction Electromagnetic Radiating System (MERS) Advanced Technology Demonstration (ATD) is to demonstrate the feasibility of combining at least four shipboard functions (direction finding, JTIDS (joint

  19. Heat Radiators for Electromagnetic Pumps

    NASA Technical Reports Server (NTRS)

    Campana, R. J.

    1986-01-01

    Report proposes use of carbon/carbon composite radiators in electromagnetic coolant pumps of nuclear reactors on spacecraft. Carbon/carbon composite materials function well at temperatures in excess of 2,200 K. Aluminum has melting temperature of only 880 K.

  20. Fluid Properties in Electromagnetic Fields

    NASA Astrophysics Data System (ADS)

    Cantu, Sean; Masood, Samina

    2012-02-01

    We study the effect of electromagnetic fields on the fluid properties to see if the modifications in the fluids properties are causing the effect of magnetic fields on the bacterial growth. For this purpose we design a simple experiment to study the changes in spectrum of light through the nutrient broth that is the fluid used to study the bacterial growth.

  1. Electromagnetic waves in free space

    Microsoft Academic Search

    J. A. Bittencourt

    1979-01-01

    A review of the fundamental features of electromagnetic waves propagating in free space are reviewed as well as some of the basic concepts about waves, necessary for the study of wave phenomena in plasmas. The solution of the wave equation, satisfied by the electric and magnetic field vectors, in terms of plane waves is presented along with the characteristics of

  2. Electromagnetic waves at parabolic boundaries

    Microsoft Academic Search

    Pierre Hillion

    1997-01-01

    We first discuss the scattering of an electromagnetic plane wave at a perfectly conducting parabolic cylinder when the incident wave travels toward the edge of the cylinder and parallel to its axis. We get in terms of Weber functions an exact solution which is simple enough to make possible a comparison with approximate solutions developed to tackle diffraction at rounded

  3. Electromagnetic Implosion Using an Array

    Microsoft Academic Search

    Carl E. Baum; Serhat Altunc; Christos G. Christodoulou; Edl Schamiloglu

    2008-01-01

    This paper considers the use of a spherical array of sources producing a large fast-transient electromagnetic wave near the center of a sphere. For comparison, a lens type of implosion impulse radiating antenna (IRA) is included as an appendix. This complements the prolate-spheroidal focusing-reflector type of IRA, which has been already appearing in journal papers.

  4. Detectability by Electromagnetic Sounding Systems

    Microsoft Academic Search

    Rajni Verma

    1977-01-01

    An analysis has been made of the detectability of subsurface layers by the four electromagnetic (EM) depth sounding systems: horizontal coplanar loops, perpendicular loops, vertical coplanar loops, and vertical coaxial loops. For computing the mutual coupling ratios (the EM response function) the linear digital filter method has been used. The linear digital filter method as applied in computing the EM

  5. Transient electromagnetic sounding for groundwater

    Microsoft Academic Search

    David V. Fitterman; Mark T. Stewart

    1986-01-01

    The feasibility of using the transient electromagnetic sounding (TS or TDEM) method for groundwater exploration can be studied by means of numerical models. As examples of its applicability to groundwater exploration, we study four groundwater exploration problems: (1) mapping of alluvial fill and gravel zones over bedrock; (2) mapping of sand and gravel lenses in till; (3) detection of salt

  6. Electromagnetic study of multilayer media

    Microsoft Academic Search

    J. P. Booth; S. Brown

    2006-01-01

    This paper discusses a basic electromagnetic analysis of multilayer material used in a radome application. The purpose of this work is to investigate a possible new configuration for a missile seeker. The discussion is based on computer simulations with real world applications. This effort is being conducted in the RF Technology Division of the Applied Sensors, Guidance, and Electronics Directorate

  7. Interpreting Electromagnetic Reflections In Glaciology

    Microsoft Academic Search

    O. Eisen; U. Nixdorf; F. Wilhelms; D. Steinhage; H. Miller

    2002-01-01

    Electromagnetic reflection (EMR) measurements are active remote sensing methods that have become a major tool for glaciological investigations. Although the basic pro- cesses are well understood, the unambiguous interpretation of EMR data, especially internal layering, still requires further information. The Antacrtic ice sheet provides a unique setting for investigating the relation between physical­chemical properties of ice and EMR data. Cold

  8. Electromagnetic Levitation of a Disc

    ERIC Educational Resources Information Center

    Valle, R.; Neves, F.; de Andrade, R., Jr.; Stephan, R. M.

    2012-01-01

    This paper presents a teaching experiment that explores the levitation of a disc of ferromagnetic material in the presence of the magnetic field produced by a single electromagnet. In comparison to the classical experiment of the levitation of a sphere, the main advantage of the proposed laboratory bench is that the uniform magnetic field…

  9. Electromagnetically assisted sheet metal stamping

    Microsoft Academic Search

    Jianhui Shang; Glenn Daehn

    2011-01-01

    A new approach, electromagnetically assisted sheet metal stamping, has been developed to alter strain distribution and improve formability in sheet metal stamping. In this study, this new approach was applied to form a non-symmetric panel from Al 6111-T4. The results show that this new approach greatly increased the draw depth of the formed panel, compared with conventional stamping. A detailed

  10. A Hamiltonian electromagnetic gyrofluid model

    SciTech Connect

    Waelbroeck, F. L.; Hazeltine, R. D.; Morrison, P. J. [Institute for Fusion Studies, University of Texas, Austin, Texas 78712 (United States)

    2009-03-15

    An isothermal truncation of the electromagnetic gyrofluid model of Snyder and Hammett [Phys. Plasmas 8, 3199 (2001)] is shown to be Hamiltonian. The corresponding noncanonical Lie-Poisson bracket and its Casimir invariants are presented. The invariants are used to obtain a set of coupled Grad-Shafranov equations describing equilibria and propagating coherent structures.

  11. Integrating electromagnetic launchers on ships

    Microsoft Academic Search

    Antonios Challita; John Barber; John Ykema; Cliff Allen

    2004-01-01

    Naval combatant ships of the future will have high power electrically powered weapons systems, including electromagnetic launchers. Integrating high power electric gun systems into ships poses unique issues that ship designers have not faced before. These issues must be identified and addressed early in the conceptual design stage for successful development and integration of high power electric gun systems into

  12. Computational design for electromagnetic simulations

    NASA Astrophysics Data System (ADS)

    Glasby, Ryan Steven

    An automatic computational procedure has been developed to efficiently and accurately design the shape of complicated electromagnetic objects. These electromagnetic objects can be simulated for operation at high frequencies (˜10 GHz), and can be comprised of dissimilar materials. The automated design procedure consists of linking together an original electromagnetic field simulation tool, an original adjoint routine for obtaining sensitivity derivatives, and an original grid-smoothing tool with an existing optimization package. The electromagnetic field simulation software employs a temporally and spatially higher-order accurate Streamline Upwind/Petrov-Galerkin finite-element method that numerically solves Maxwell's equations in the time domain using implicit time stepping. The software for computing sensitivity derivatives employs a reverse-mode time-accurate discrete adjoint methodology that is formulated to automatically maintain consistency with the electromagnetic field simulation software. Grid smoothing is achieved using a spatially higher-order accurate Galerkin finite-element method that generates a numerical solution to the linear elastic equations. All computational solutions to the linear systems present in each software tool are obtained using the Generalized Minimum Residual algorithm with block diagonal preconditioning. Each software tool is implemented using a parallel processing paradigm and is therefore capable of being executed on a distributed memory supercomputer. The order of accuracy of the electromagnetic field simulation software has been determined by using comparisons with exact solutions. The field software's results were compared to the exact solution of a rectangular resonant cavity. In all cases, the order properties of the field software exceed theoretical expectations when linear, quadratic, and cubic tetrahedral elements are employed to discretize the field. To demonstrate the consistency of the adjoint-based sensitivity derivates with those obtained directly from the field solver, derivatives have been extracted from the field software using a complex variable technique. The sensitivity derivatives from the reverse-mode time-accurate discrete adjoint method were then compared and demonstrated to agree to at least seven decimal places. As a demonstration of the assembled technologies, the optimization procedure successfully and efficiently modified the shape of two electromagnetic objects to reduce a specified cost function. A dielectric cube, under the influence of a propagating plane wave, was repositioned within a larger free space volume so that the field variables on the surface of the cube match desired values at a specified time. A similar demonstration case has also been conducted to modify the shape of a dielectric ellipsoid, under the same conditions as the cube.

  13. Cosmological electromagnetic fields and dark energy

    Microsoft Academic Search

    Jose Beltrįn Jiménez; Antonio L. Maroto

    2009-01-01

    We show that the presence of a temporal electromagnetic field on cosmological scales generates an effective cosmological constant which can account for the accelerated expansion of the universe. Primordial electromagnetic quantum fluctuations produced during electroweak scale inflation could naturally explain the presence of this field and also the measured value of the dark energy density. The behavior of the electromagnetic

  14. Electromagnetic Attacks and Countermeasures Pankaj Rohatgi

    E-print Network

    for "transient electromagnetic pulse emanation standard". In January 2001, in re- sponse to a FreedomChapter 15 Electromagnetic Attacks and Countermeasures Pankaj Rohatgi 15.1 Introduction and History;15 Electromagnetic Attacks and Countermeasures 409 side-channel to other side-channels and a methodology for leakage

  15. Acousto-electromagnetic Tomography Habib Ammari

    E-print Network

    Garnier, Josselin

    Acousto-electromagnetic Tomography Habib Ammari Emmanuel Bossy Josselin Garnier§ Laurent Seppecher June 28, 2012 Abstract The aim of this paper is to develop a mathematical framework for acousto-electromagnetic tomography and to introduce an efficient reconstruction algorithm. In electromagnetic wave imaging

  16. Electromagnetics from Simulation to Optimal Design

    E-print Network

    Lang, Annika

    1 Electromagnetics from Simulation to Optimal Design Christian Hafner Laboratory for Electromagnetic Fields and Microwave Electronics (IFH) ETH Zurich (Switzerland) Lab: http://www.ifh.ee.ethz.ch COG 23, 2013 #12;2 IFH courses · Advanced engineering electromagnetics (Leuchtmann, start spring 2014

  17. 611: Electromagnetic Theory Problem Sheet 5

    E-print Network

    Pope, Christopher

    611: Electromagnetic Theory Problem Sheet 5 (1) Consider the expression for the electric field due · dS over a spherical surface that encloses the moving charge. (2a) Consider an electromagnetic wave density and the Poynting vector. (2c) Repeat the steps in (2a) and (2b) for an electromagnetic wave

  18. Electromagnetic Formation Flight of Satellite Arrays

    E-print Network

    Electromagnetic Formation Flight of Satellite Arrays Daniel W. Kwon and David W. Miller February 2005 SSL # 2-05 #12;#12;Electromagnetic Formation Flight of Satellite Arrays By DANIEL W. KWON S;#12;Electromagnetic Formation Flight of Satellite Arrays by DANIEL W. KWON Submitted to the Department of Aeronautics

  19. Electromagnetic Corrections in Staggered Chiral Perturbation Theory

    E-print Network

    Bernard, Claude

    Electromagnetic Corrections in Staggered Chiral Perturbation Theory C. Bernard and E.D. Freeland perturbation theory including electromagnetism, and discuss the extent to which quenched-photon simulations can-lat]17Nov2010 #12;Electromagnetic Corrections in Staggered Chiral Perturbation Theory E.D. Freeland 1

  20. Physics 4: Introductory Physics Electromagnetism and Light

    E-print Network

    Fygenson, Deborah Kuchnir

    Physics 4: Introductory Physics Electromagnetism and Light Professor Jeffrey D. Richman Department: Electromagnetism and Light Welcome to Physics 4! What is your goal in life? If it is to become an engineer or to pursue a career in science, this is a key class for you. Understanding electromagnetism and light

  1. Electromagnetic Interrogation of Dielectric Materials 1

    E-print Network

    Electromagnetic Interrogation of Dielectric Materials 1 H.T. Banks M.W. Buksas Center for Research grant P200A40730. #12; Abstract We investigate time domain based electromagnetic inverse problems electromagnetic phenomenon. For our purposes, we categorize the materials and the models employed to describe them

  2. Some Student Conceptions of Electromagnetic Induction

    ERIC Educational Resources Information Center

    Thong, Wai Meng; Gunstone, Richard

    2008-01-01

    Introductory electromagnetism is a central part of undergraduate physics. Although there has been some research into student conceptions of electromagnetism, studies have been sparse and separated. This study sought to explore second year physics students' conceptions of electromagnetism, to investigate to what extent the results from the present…

  3. 611: Electromagnetic Theory Problem Sheet 5

    E-print Network

    Pope, Christopher

    611: Electromagnetic Theory Problem Sheet 5 (1a) Show that the energy-momentum tensor for the electromagnetic field is tracefree, i.e. Tµ µ = 0. What would happen, in a spacetime dimension d = 4? (Assume) Show that the energy-momentum tensor for the electromagnetic field can be written as Tµ = 1 8 (Fµ F

  4. 611: Electromagnetic Theory Problem Sheet 5

    E-print Network

    Pope, Christopher

    611: Electromagnetic Theory Problem Sheet 5 (1a) The Null Energy Condition on an energy = (k, 0, 0, k), show that the energy-momentum tensor Tµ = 1 4 Fµ F - 1 4µ F F (1) for electromagnetism if the equality kµ k Tµ = 0 is attained. (2) Show that the energy-momentum tensor for electromagnetism can

  5. 611: Electromagnetic Theory Problem Sheet 6

    E-print Network

    Pope, Christopher

    611: Electromagnetic Theory Problem Sheet 6 (1) Consider the expression for the electric field due · dS over a spherical surface that encloses the moving charge. (2a) Consider an electromagnetic wave density and the Poynting vector. (2c) Repeat the steps in (2a) and (2b) for an electromagnetic wave

  6. Course Outline Physics 433: Electromagnetism II

    E-print Network

    Course Outline Physics 433: Electromagnetism II Spring 2014 Prof. Keun Hyuk "Ken" Ahn 483 Tiernan of this course is on the elementary concepts of electromagnetic fields. Upon completion of the course, students are expected to be capable of using the Maxwell equations to calculate simple electromagnetic problems, ranging

  7. MUSES: multi-sensor soil electromagnetic sounding

    Microsoft Academic Search

    G. Vannaroni; E. Pettinelli; C. Ottonello; A. Cereti; G. Della Monica; D. Del Vento; A. M. Di Lellis; R. Di Maio; R. Filippini; A. Galli; A. Menghini; R. Orosei; S. Orsini; S. Pagnan; F. Paolucci; A. R. Pisani; G. Schettini; M. Storini; G. Tacconi

    2004-01-01

    The authors describe the performance of a multi-sensor package designed to measure the electromagnetic properties of the subsurface during future landing missions to Mars. The package consists of a soil dielectric spectroscopy probe (SDSP), a ground penetrating radar (GPR) and a time domain electromagnetic measurement (TDEM) system that, using different methods, estimate the electromagnetic properties of the shallow subsurface at

  8. 532 IEEE TRANSACTIONS ON ELECTROMAGNETIC COMPATIBILITY, VOL. 51, NO. 3, AUGUST 2009 Lightning Electromagnetic Field Coupling to

    E-print Network

    Florida, University of

    A. Uman, Fellow, IEEE (Invited Paper) Abstract--The evaluation of electromagnetic transients in over lightning location systems. Index Terms--Electromagnetic transients, electromagnetic tran- sient program532 IEEE TRANSACTIONS ON ELECTROMAGNETIC COMPATIBILITY, VOL. 51, NO. 3, AUGUST 2009 Lightning

  9. Novel electromagnetic materials from functionalized structures

    NASA Astrophysics Data System (ADS)

    Xiao, Xiao

    Materials, exhibiting the novel electromagnetic responses those may not be found in nature, have the potential to manipulate the electromagnetic field passing through them. Consequently, these materials promise a number of applications, such as highly sensitive sensor, superlenses, high-gain antennas and electromagnetic wave cloaking. In the literature we would investigate various electromagnetic materials composed from functionalized structures (components). The novel electromagnetic materials can be photonic crystals, which are composed of the periodic dielectric or metallic structures. The propagation of the electromagnetic wave in photonic crystals is affected in the same way as the electrons propagating in the periodic potential in solid. We demonstrated that the photonic crystals can be used as a tool to tune the birefringence of the electromagnetic field. Metamaterials, which are composed of the artificial structures exhibiting strong local resonances, are also a kind of novel electromagnetic materials. The strong local resonance can squeeze the wavelength of the incoming electromagnetic field to the subwavelength region (i.e. superlenses) and revise the effective electromagnetic response of the materials (i.e. the negative indexes). For metamaterials we focus on the Plasmonic metamaterials in the thesis: we would show that these materials could be used to guide electromagnetic wave or introduce various kinds of extraordinary transmissions, both of which, of course, are achieved at subwavelength region. Moreover, the novel electromagnetic materials can be even the topological insulators, whose non-trivial electronic surface states can have extraordinary responses under the electromagnetic field. These non-trivial quantum hall surface states can introduce the mode conversion between different electromagnetic modes on the surfaces of the topological insulators and thus modify the propagation properties of the electromagnetic field through them. We would demonstrate that the non-trivial surface states of the topological insulators could modify the coherence of the thermal radiation from them.

  10. Some Wave Equations for Electromagnetism and Gravitation

    E-print Network

    Zi-Hua Weng

    2010-08-11

    The paper studies the inferences of wave equations for electromagnetic fields when there are gravitational fields at the same time. In the description with the algebra of octonions, the inferences of wave equations are identical with that in conventional electromagnetic theory with vector terminology. By means of the octonion exponential function, we can draw out that the electromagnetic waves are transverse waves in a vacuum, and rephrase the law of reflection, Snell's law, Fresnel formula, and total internal reflection etc. The study claims that the theoretical results of wave equations for electromagnetic strength keep unchanged in the case for coexistence of gravitational and electromagnetic fields. Meanwhile the electric and magnetic components of electromagnetic waves can not be determined simultaneously in electromagnetic fields.

  11. Electromagnetic response of Weyl semimetals.

    PubMed

    Vazifeh, M M; Franz, M

    2013-07-12

    It has been suggested recently, based on subtle field-theoretical considerations, that the electromagnetic response of Weyl semimetals and the closely related Weyl insulators can be characterized by an axion term ?E·B with space and time dependent axion angle ?(r,t). Here we construct a minimal lattice model of the Weyl medium and study its electromagnetic response by a combination of analytical and numerical techniques. We confirm the existence of the anomalous Hall effect expected on the basis of the field theory treatment. We find, contrary to the latter, that chiral magnetic effect (that is, ground state charge current induced by the applied magnetic field) is absent in both the semimetal and the insulator phase. We elucidate the reasons for this discrepancy. PMID:23889433

  12. The hidden geometry of electromagnetism

    E-print Network

    Hadad, Yaron; Kaminer, Ido; Elitzur, Avshalom C

    2015-01-01

    Nearly all field theories suffer from singularities when particles are introduced. This is true in both classical and quantum physics. Classical field singularities result in the notorious self-force problem, where it is unknown how the dynamics of a particle change when the particle interacts with its own (self) field. Self-force is a pressing issue and an active research topic in gravitational phenomena, as well as a source of controversies in classical electromagnetism. In this work, we study a hidden geometrical structure manifested by the electromagnetic field-lines that has the potential of eliminating all singularities from classical electrodynamics. We explore preliminary results towards a consistent way of treating both self- and external fields.

  13. Electromagnetic transduction of ultrasonic waves

    NASA Astrophysics Data System (ADS)

    Passarelli, Frank; Alers, George; Alers, Ron

    2012-05-01

    Excitation and detection of ultrasonic vibrations without physical contact has proven to be of great commercial value. First used to excite the resonant vibration of bar shaped laboratory specimens in the 1930's, it was Bruce Thompson's contributions in 1973-5 that launched their practical application to a wide range of difficult NDE problems. As a fresh PhD, he championed the use of mathematical models for the electromagnetic transduction process in order to guide the design and construction of practical transducers. His early papers presented both theoretical and experimental results that exposed the wide range of wave types that could be generated along with the environmental conditions that could be overcome. Several laboratories around the world established research programs to apply the electromagnetic transducer (EMAT) to specific NDE problems. This paper will summarize those applications made by the authors.

  14. Electromagnetic shielding in quantum metrology

    E-print Network

    Yao Jin; Hongwei Yu

    2015-04-21

    The dynamics of the quantum Fisher information of the parameters of the initial atomic state and atomic transition frequency is studied, in the framework of open quantum systems, for a static polarizable two-level atom coupled in the multipolar scheme to a bath of fluctuating vacuum electromagnetic fields without and with the presence of a reflecting boundary. Our results show that in the case without a boundary, the electromagnetic vacuum fluctuations always cause the quantum Fisher information of the initial parameters and thus the precision limit of parameter estimation to decrease. Remarkably, however, with the presence of a boundary, the quantum Fisher information becomes position and atomic polarization dependent, and as a result, it may be enhanced as compared to that in the case without a boundary and may even be shielded from the influence of the vacuum fluctuations in certain circumstances as if it were a closed system.

  15. Electromagnetic moments of quasistable particle

    SciTech Connect

    Ledwig, Tim; Pascalutsa, Vladimir; Vanderhaeghen, Marc [Institut fuer Kernphysik, Johannes Gutenberg Universitaet Mainz, D-55099 Mainz (Germany)

    2010-11-01

    We deal with the problem of assigning electromagnetic moments to a quasistable particle (i.e., a particle with mass located at the particle's decay threshold). In this case, an application of a small external electromagnetic field changes the energy in a nonanalytic way, which makes it difficult to assign definitive moments. On the example of a spin-1/2 field with mass M{sub *} interacting with two fields of masses M and m, we show how a conventionally defined magnetic dipole moment diverges at M{sub *}=M+m. We then show that the conventional definition makes sense only when the values of the applied magnetic field B satisfy |eB|/2M{sub *}<<|M{sub *}-M-m|. We discuss implications of these results to existing studies in electroweak theory, chiral effective-field theory, and lattice QCD.

  16. Electromagnetic instability in holographic QCD

    NASA Astrophysics Data System (ADS)

    Hashimoto, Koji; Oka, Takashi; Sonoda, Akihiko

    2015-06-01

    Using the AdS/CFT correspondence, we calculate the vacuum decay rate for the Schwinger effect in confining large N c gauge theories. The instability is induced by thecorrespondence, we calculate the vacuum quark antiquark pair creation triggered by strong electromagnetic fields. The decay rate is obtained as the imaginary part of the Euler-Heisenberg effective Lagrangian evaluated from the D-brane action with a constant electromagnetic field in holographic QCD models such as the Sakai-Sugimoto model and the deformed Sakai-Sugimoto model. The decay rate is found to increase with the magnetic field parallel to the electric field, while it decreases with the magnetic field perpendicular to the electric field. We discuss generic features of a critical electric field as a function of the magnetic field and the QCD string tension in the Sakai-Sugimoto model.

  17. Dark Energy, Gravitation and Electromagnetism

    Microsoft Academic Search

    B. G. Sidharth; B. M. Birla

    2004-01-01

    In the context of the fact that the existence of dark energy causing the\\u000aaccelerated expansion of the universe has been confirmed by the WMAP and the\\u000aSloan Digital Sky Survey, we re-examine gravitation itself, starting with the\\u000aformulation of Sakharov and show that it is possible to obtain gravitation in\\u000aterms of the electromagnetic charge of elementary particles, once

  18. Current-driven electromagnetic modes

    Microsoft Academic Search

    J L Sperling; D K Bhadra

    1979-01-01

    The dispersion relation for current-driven electromagnetic instabilities in an inhomogeneous slab geometry is derived and analyzed. It is shown that current in the direction of the equilibrium magnetic field, as well as transverse current gradients can strongly modify the drift-Alfven dispersion relation as given by Kadomtsev (1965). If the perpendicular wavelength is much larger than the ion gyro-radius there can

  19. Techniques for analyzing electromagnetic transients

    Microsoft Academic Search

    H. W. Dommel

    1997-01-01

    With few exceptions, power system electromagnetic transients must be studied on a three-phase basis rather than on a positive sequence single-phase basis. For example, the three-phase opening of a circuit breaker is no longer a symmetric event in the ms range. Current interruption takes place at current zero, and one phase would open first at its current zero, while the

  20. Dark Energy, Gravitation and Electromagnetism

    E-print Network

    B. G. Sidharth

    2004-01-08

    In the context of the fact that the existence of dark energy causing the accelerated expansion of the universe has been confirmed by the WMAP and the Sloan Digital Sky Survey, we re-examine gravitation itself, starting with the formulation of Sakharov and show that it is possible to obtain gravitation in terms of the electromagnetic charge of elementary particles, once the ZPF and its effects at the Compton scale are taken into account.

  1. Pulsed power for electromagnetic launching

    SciTech Connect

    Cowan, M

    1980-12-01

    There are system advantages to producing power for electromagnetic propulsion by real-time generation rather than by a sequence of generation-storage-switching. The best type of generator for this purpose is the flux compression generator. Different types of flux compression generator which have been developed at Sandia National Laboratories are reviewed and their applications to electric launching are discussed. New experimental facilities for producing more powerful generators are described and cost comparisons are made.

  2. ELECTROMAGNETIC MODELING OF RETINAL PHOTORECEPTORS

    Microsoft Academic Search

    Cahit Canbay

    2008-01-01

    Abstract—New electromagnetic models for the rods and,cones that are the,photoreceptors at,the,back,of the,retina are developed and simulated in order to explain the roles of dimension, geometrical structure, directional sensitivity and visual pigments of the photoreceptors in the reception of visible light. The rods and cones are modeled as uniform and quasi-tapered helical antennas, respectively. The results of the model study show

  3. Electromagnetic sounding of geothermal zones

    Microsoft Academic Search

    Viacheslav Spichak; Adele Manzella

    2009-01-01

    Electromagnetic (EM) data provide a substantial contribution to the geophysical mapping and monitoring of geothermal reservoirs. This paper presents an up-to-date picture of the achievements of EM methods for geothermal exploration as they have emerged over the last few years. It has been proved that EM sounding of geothermal zones and distant monitoring macro-parameters of the reservoirs, fluid-filled faults and

  4. Electromagnetic Wave Resistivity MWD Tool

    Microsoft Academic Search

    Paul Rodney; MacMillan Wisler

    1986-01-01

    This paper is an overview of the development of a 2-MHz (2 x 10ā¶ -cycle\\/sec) measurement-while-drilling (MWD) resistivity logging tool. This tool uses propagating electromagnetic waves rather than the pseudostatic fields of its low-frequency counterparts. The basic theory of operation is presented along with a discussion of the factors that affect tool response and the compromises that led to the

  5. Electromagnetic brake/clutch device

    NASA Technical Reports Server (NTRS)

    Vranish, John M. (inventor)

    1994-01-01

    An electromagnetic brake/clutch device includes a drive shaft supported by at least one bearing for transmitting torque, a housing, affixed to prevent its rotation, surrounding the drive shaft, and an electromagnetically activated device within the housing to selectively prevent and allow rotation of the drive shaft. The electromagnetically activated device includes a plurality of cammed rollers to prevent counter-clockwise rotation of the drive shaft. The drive shaft includes a circumferential disk and the housing includes a reaction ring for engagement with the plurality of cammed rollers. The plurality of cammed rollers are released from engagement with the circumferential disk and the reaction ring by a plurality of tripping mechanisms within the housing. The tripping action uses the locking force to act as a release force merely by changing the boundary conditions of the roller interface angles. The tripping mechanisms include trippers for disengaging the plurality of cammed rollers and an anvil shaped portion for providing lateral movement of the trippers. The plurality of cammed rollers is preloaded to engagement with the circumferential disk and reaction ring by a spring, and is located with respect to an adjacent tripping mechanism with another spring.

  6. The nature of electromagnetic energy

    E-print Network

    Jerrold Franklin

    2012-05-29

    The nature of the electromagnetic (EM) energy for general charge and current distributions is analyzed. There are two well known forms for calculating EM energy as the integral over all space of either the electromagnetic fields: $u_{\\bf EB}=({\\bf E\\bcdot D+B\\bcdot H})/8\\pi$, or the electromagnetic potentials and charge-current densities: $u_{\\rho{\\bf A}}=1/2(\\rho\\phi+{\\bf j\\bcdot A})$. We discuss the appropriate use of each of these forms in calculating the total EM energy and the EM energy within a limited volume. We conclude that only the form $u_{\\bf EB}$ can be considered as a suitable EM energy density, while either form can be integrated to find the total EM energy. However, bounding surface integrals (if they don't vanish) must be included when using the $u_{\\bf EB}$ form. Including these surface integrals resolves some seeming paradoxes in the energy of electric or magnetic dipoles in uniform fields

  7. Electromagnetic sensing of chiral materials

    NASA Astrophysics Data System (ADS)

    Crittenden, Paul Edward

    The circular decomposition of Maxwell's equations for chiral materials is given. The Fourier transforms of the Green's functions for the electromagnetic waves on both sides of a flat interface between two semi-infinite chiral materials are derived. The solution is expressed in terms of the characteristic right and left circularly polarized waves. The Green's functions are converted into alternate, modal, representations suitable for the complete expansion of the fields above and below a laterally varying interface between two chiral materials with laterally varying material properties. The dominant reflection and transmission paths are identified using asymptotic expansions of the inverse transform. Generalized Fourier transform pairs appropriate for expanding the electromagnetic fields above and below a variable interface between chiral materials are derived. The generalized Fourier transform pairs are used to obtain two sets of coupled ordinary differential equations for the transforms of the forward and backward wave amplitudes of the z-component of the magnetic field. Under appropriate assumptions for particular types of surfaces, the set of differential equations can be solved numerically or iteratively. From the solutions the transforms of the fields can be found and inverted to obtain the electromagnetic fields. The results obtained and possible future work have direct applications to the near and far field discrimination between chiral media as well as the optimization of chiral materials. Chiral materials are of interest in a wide range of fields and as a result this dissertation would have an equally wide range of applications.

  8. Electromagnetic Effects in SDF Explosions

    SciTech Connect

    Reichenbach, H; Neuwald, P; Kuhl, A L

    2010-02-12

    The notion of high ion and electron concentrations in the detonation of aluminized explosive mixtures has aroused some interest in electro-magnetic effects that the SDF charges might generate when detonated. Motivated by this interest we have started to investigate whether significant electro-magnetic effects show up in our small-scale experiments. However, the design of instrumentation for this purpose is far from straightforward, since there are a number of open questions. Thus the main aim of the feasibility tests is to find - if possible - a simple and reliable method that can be used as a diagnostic tool for electro-magnetic effects. SDF charges with a 0.5-g PETN booster and a filling of 1 g aluminum flakes have been investigated in three barometric bomb calorimeters with volumes ranging from 6.3 l to of 6.6 l. Though similar in volume, the barometric bombs differed in the length-to-diameter ratio. The tests were carried out with the bombs filled with either air or nitrogen at ambient pressure. The comparison of the test in air to those in nitrogen shows that the combustion of TNT detonation products or aluminum generates a substantial increase of the quasi-steady overpressure in the bombs. Repeated tests in the same configuration resulted in some scatter of the experimental results. The most likely reason is that the aluminum combustion in most or all cases is incomplete and that the amount of aluminum actually burned varies from test to test. The mass fraction burned apparently decreases with increasing aspect ratio L/D. Thus an L/D-ratio of about 1 is optimal for the performance of shock-dispersed-fuel combustion. However, at an L/D-ratio of about 5 the combustion still yields appreciable overpressure in excess of the detonation. For a multi-burst scenario in a tunnel environment with a number of SDF charges distributed along a tunnel section a spacing of 5 tunnel diameter and a fuel-specific volume of around 7 l/g might provide an acceptable compromise between optimizing the combustion performance and keeping the number of elementary charges low. Further tests in a barometric bomb calorimeter of 21.2 l volume were performed with four types of aluminum. The mass fraction burned in this case appeared to depend on the morphology of the aluminum particles. Flake aluminum exhibited a better performance than granulated aluminum with particle sizes ranging from below 25 {micro}m to 125 {micro}m for the coarsest material. In addition, a feasibility study on electro-magnetic effects from SDF charges detonated in a tunnel has been performed. A method was developed to measure the local, unsteady electro-conductivity in the detonation/combustion products cloud. This method proved to yield reproducible results. A variety of methods were tested with regard to probing electro-magnetic pulses from the detonation of SDF charges. The results showed little reproducibility and were small compared to the effect from pulsed high voltage discharges of comparatively small energy (around 32 J). Thus either no significant electromagnetic pulse is generated in our small-scale tests or the tested techniques have to be discarded as too insensitive or too limited in bandwidth to detect possibly very high frequency electro-magnetic disturbances.

  9. Electrothermal-electromagnetic hybrid thruster research

    NASA Technical Reports Server (NTRS)

    Kelly, A. J.; Jahn, R. G.; Myers, R.

    1987-01-01

    The energy deposition and acceleration mechanisms in the electrothermal-electromagnetic hybrid regime of coaxial plasma thruster operation are examined both theoretically and experimentally. Theoretical results show that the major trade-offs in the hybrid regime are between efficiency and specific impulse: increasing the influence of electromagnetic forces increases I(sp), but within the operating range examined, decreases the efficiency. Experiments conducted in the predominantly electromagnetic regime agree with the predictions. Anode power deposition is the dominant loss process.

  10. Thin sheet casting with electromagnetic pressurization

    DOEpatents

    Walk, Steven R. (Winterport, ME); Slepian, R. Michael (Pittsburgh, PA); Nathenson, Richard D. (Pittsburgh, PA); Williams, Robert S. (Fairfield, OH)

    1991-01-01

    An apparatus, method and system for the casting of thin strips or strips of metal upon a moving chill block that includes an electromagnet located so that molten metal poured from a reservoir onto the chill block passes into the magnetic field produced by the electromagnet. The electromagnet produces a force on the molten metal on said chill block in the direction toward said chill block in order to enhance thermal contact between the molten metal and the chill block.

  11. Exterior Differential Forms in Teaching Electromagnetics

    Microsoft Academic Search

    Peter Russer

    \\u000a As wireless communications is penetrating into the millimeterwave frequencies, communications engineers need an improved background\\u000a and working knowledge in electromagnetics. The study of electromagnetics is fundamental to the advancement of communications\\u000a engineering and information technology to push the frontiers of the ultra-fast and the high bandwidth. Especially engineers\\u000a using CAD tools for the electromagnetic design of circuits and antennas need

  12. Pulsed Electromagnet Emat for High Temperatures

    NASA Astrophysics Data System (ADS)

    Hernandez-Valle, F.; Dixon, S.

    2010-02-01

    We presented recently a design of Electromagnetic Acoustic Transducer (EMAT) that uses a pulsed electromagnet to provide the required magnetic field for operation. This new EMAT exhibited a significant improvement in the generated ultrasonic signal amplitude and signal to noise ratio, for operation on mild steel samples at room temperature, compared to equivalent EMATs that use permanent magnets. Results for using the pulsed electromagnet EMAT to generate and detect shear waves in mild steel at elevated temperatures are presented here.

  13. Manager's Role in Electromagnetic Interference (EMI) Control

    NASA Technical Reports Server (NTRS)

    Sargent, Noel B.; Lewis, Catherine C.

    2013-01-01

    This presentation captures the essence of electromagnetic compatibility (EMC) engineering from a project manager's perspective. It explains the basics of EMC and the benefits to the project of early incorporation of EMC best practices. The EMC requirement products during a project life cycle are identified, along with the requirement verification methods that should be utilized. The goal of the presentation is to raise awareness and simplify the mystique surrounding electromagnetic compatibility for managers that have little or no electromagnetics background

  14. An electromagnetic analog of gravitational wave memory

    E-print Network

    Lydia Bieri; David Garfinkle

    2013-09-10

    We present an electromagnetic analog of gravitational wave memory. That is, we consider what change has occurred to a detector of electromagnetic radiation after the wave has passed. Rather than a distortion in the detector, as occurs in the gravitational wave case, we find a residual velocity (a "kick") to the charges in the detector. In analogy with the two types of gravitational wave memory ("ordinary" and "nonlinear") we find two types of electromagnetic kick.

  15. Electromagnetic interactions at RHIC and LHC

    E-print Network

    M. C. Guclu

    2008-11-15

    At LHC energies the Lorentz factor will be 3400 for the Pb + Pb collisions and the electromagnetic interactions will play important roles. Cross sections for the electromagnetic particle productions are very large and can not be ignored for the lifetimes of the beams and background. In this article, we are going to study some of the electromagnetic processes at RHIC and LHC and show the cross section calculations of the electron-positron pair production with the giant dipole resonance of the ions.

  16. Electromagnetic wave scattering by Schwarzschild black holes

    E-print Network

    Luķs C. B. Crispino; Sam R. Dolan; Ednilton S. Oliveira

    2009-05-20

    We analyze the scattering of a planar monochromatic electromagnetic wave incident upon a Schwarzschild black hole. We obtain accurate numerical results from the partial wave method for the electromagnetic scattering cross section, and show that they are in excellent agreement with analytical approximations. The scattering of electromagnetic waves is compared with the scattering of scalar, spinor and gravitational waves. We present a unified picture of the scattering of all massless fields for the first time.

  17. 22.105 Electromagnetic Interactions, Fall 1998

    E-print Network

    Hutchinson, I. H. (Ian H.)

    Principles and applications of electromagnetism, starting from Maxwell's equations, with emphasis on phenomena important to nuclear engineering and radiation sciences. Solution methods for electrostatic and magnetostatic ...

  18. Electromagnetic Compatibility for the Space Shuttle

    NASA Technical Reports Server (NTRS)

    Scully, Robert C.

    2004-01-01

    This slide presentation reviews the Space Shuttle electromagnetic compatibility (EMC). It includes an overview of the design of the shuttle with the areas that are of concern for the electromagnetic compatibility. It includes discussion of classical electromagnetic interference (EMI) and the work performed to control the electromagnetic interference. Another area of interest is electrostatic charging and the threat of electrostatic discharge and the attempts to reduce damage to the Shuttle from these possible hazards. The issue of electrical bonding is als reviewed. Lastly the presentation reviews the work performed to protect the shuttle from lightning, both in flight and on the ground.

  19. Electromagnetic Scattering from Foliage Camouflaged Hard Targets,

    E-print Network

    Sarabandi, Kamal

    Electromagnetic Scattering from Foliage Camouflaged Hard Targets, in VHF-band Mojtaba Dehmollaian. Then using this formulation, and single scattering theory the backscattered field from a camouflaged complex

  20. Noncontacting ultrasonic and electromagnetic HTS tape NDE

    SciTech Connect

    Telschow, K.L.; Bruneel, F.W.; Walter, J.B.; Koo, L.S.

    1996-10-01

    Two noncontacting nondestructive evaluation techniques (electromagnetic and ultrasonic) for inspection of high temperature superconducting tapes are described. Results for Ag-clad BSCCO tapes are given.

  1. Logic for electromagnetic field patterns

    E-print Network

    Kouzaev, G a

    2008-01-01

    It is assumed that the digital-like spatio-time brain activity might be caused by non-topological transformations of patterns in the cortex which is a linear, analog and active system. Such an effect can be modeled by topologically modulated spatio-time electromagnetic signals which theory is proposed in this paper. The logical operations are performed by passive components, and a theory of them is considered. Two gates of this sort are simulated. A short review on semiconductor hardware for this type of spatial digital processing and computing is given.

  2. Electromagnetic properties of massive neutrinos

    SciTech Connect

    Dobrynina, A. A., E-mail: aleksandradobrynina@rambler.ru; Mikheev, N. V.; Narynskaya, E. N. [Demidov Yaroslavl State University (Russian Federation)] [Demidov Yaroslavl State University (Russian Federation)

    2013-10-15

    The vertex function for a virtual massive neutrino is calculated in the limit of soft real photons. A method based on employing the neutrino self-energy operator in a weak external electromagnetic field in the approximation linear in the field is developed in order to render this calculation of the vertex function convenient. It is shown that the electric charge and the electric dipole moment of the real neutrino are zero; only the magnetic moment is nonzero for massive neutrinos. A fourth-generation heavy neutrino of mass not less than half of the Z-boson mass is considered as a massive neutrino.

  3. Electromagnetic fields and health outcomes.

    PubMed

    Knave, B

    2001-09-01

    Over the past two decades, there has been increasing interest in the biological effects and possible health outcomes of weak, low-frequency electric and magnetic fields. Epidemiological studies on magnetic fields and cancer, reproduction and neurobehavioural reactions have been presented. More recently, neurological, degenerative and heart diseases have also been reported to be related to such electromagnetic fields. Furthermore, the increased use of mobile phones worldwide has focussed interest on the possible effects of radiofrequency fields of higher frequencies. In this paper, a summary is given on electromagnetic fields and health outcomes and what policy is appropriate--"no restriction to exposure", "prudent avoidance" or "expensive interventions"? The results of research studies have not been unambiguous; studies indicating these fields as being a health hazard have been published and so were studies indicating no risk at all. In "positive" studies, different types of effects have been reported despite the use of the same study design, e.g., in epidemiological cancer studies. There are uncertainties as to exposure characteristics, e.g., magnetic field frequency and exposure intermittence, and not much is known about possible confounding or effect-modifying factors. The few animal cancer studies reported have not given much help in risk assessment; and in spite of a large number of experimental cell studies, no plausible and understandable mechanisms have been presented by which a carcinogenic effect could be explained. Exposure to electromagnetic fields occurs everywhere: in the home, at work, in school, etc. Wherever there are electric wires, electric motors and electronic equipment, electromagnetic fields are created. This is one of the reasons why exposure assessment is difficult. For epidemiologists, the problems is not on the effect side as registers of diseases exist in many countries today. The problem is that epidemiologists do not know the relevant exposure characteristics to be used in their studies. In international guidelines, limits for restrictions of field exposure are several orders of magnitude above what can be measured from overhead power lines and found in "electrical" occupations. These guidelines emphasize that the state of scientific knowledge today does not warrant limiting exposure levels for the public and the work force, and that further data are required to confirm whether health hazards are present. In some countries, however, the "principle of caution" or "prudent avoidance" has been adopted; meaning the low-cost avoidance of unnecessary exposure as long as there is scientific uncertainty about its health effects. PMID:11603131

  4. Logic for electromagnetic field patterns

    E-print Network

    G. a. Kouzaev

    2008-05-29

    It is assumed that the digital-like spatio-time brain activity might be caused by non-topological transformations of patterns in the cortex which is a linear, analog and active system. Such an effect can be modeled by topologically modulated spatio-time electromagnetic signals which theory is proposed in this paper. The logical operations are performed by passive components, and a theory of them is considered. Two gates of this sort are simulated. A short review on semiconductor hardware for this type of spatial digital processing and computing is given.

  5. Electromagnetic weak turbulence theory revisited

    SciTech Connect

    Yoon, P. H. [IPST, University of Maryland, College Park, Maryland 20742 (United States); Ziebell, L. F. [Instituto de Fisica, UFRGS, Porto Alegre, RS (Brazil); Gaelzer, R.; Pavan, J. [Instituto de Fisica e Matematica, UFPel, Pelotas, RS (Brazil)

    2012-10-15

    The statistical mechanical reformulation of weak turbulence theory for unmagnetized plasmas including fully electromagnetic effects was carried out by Yoon [Phys. Plasmas 13, 022302 (2006)]. However, the wave kinetic equation for the transverse wave ignores the nonlinear three-wave interaction that involves two transverse waves and a Langmuir wave, the incoherent analogue of the so-called Raman scattering process, which may account for the third and higher-harmonic plasma emissions. The present paper extends the previous formalism by including such a term.

  6. Extremely low frequency electromagnetic fields

    SciTech Connect

    Wilson, B.W. (Pacific Northwest Lab., Richland, WA (USA). Chemical Sciences Dept.); Stevens, R.G. (Pacific Northwest Lab., Richland, WA (USA)); Anderson, L.E. (Pacific Northwest Lab., Richland, WA (USA). Life Sciences Center)

    1990-01-01

    The authors focus on that which seems to be the central scientific issue emerging from current ELF research in epidemiology and in the laboratory; namely, can ELF electromagnetic fields interact with biological systems in such a way as to increase cancer risk The authors examine how cancer risk might be related to two reproducible biological effects of ELF exposure: effects on the pineal gland and circadian biology, and effects on calcium homeostasis in cells. Because they are concerned with the possible biological mechanisms of carcinogenesis, epidemiological studies are only briefly reviewed.

  7. Electromagnetic wave energy conversion research

    NASA Technical Reports Server (NTRS)

    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.

  8. Electromagnetic code for naval applications

    NASA Astrophysics Data System (ADS)

    Crescimbeni, F.; Bessi, F.; Chiti, S.

    1988-12-01

    The use of an increasing number of electronic apparatus became vital to meet the high performance required for military Navy applications. Thus the number of antennas to be mounted on shipboard greatly increased. As a consequence of the high antenna density, of the complexity of the shipboard environment and of the powers used for communication and radar systems, the EMC (Electro-Magnetic Compatibility) problem is playing a leading role in the design of the topside of a ship. The Italian Navy has acquired a numerical code for the antenna siting and design. This code, together with experimental data measured at the Italian Navy test range facility, allows for the evaluation of optimal sitings for antenna systems on shipboard, and the prediction of their performances in the actual environment. The structure of this code, named Programma Elettromagnetico per Applicazioni Navali, (Electromagnetic Code for Naval Applications) is discussed, together with its capabilities and applications. Also the results obtained in some examples are presented and compared with the measurements.

  9. Radial Electromagnetic Press for IGNITOR

    NASA Astrophysics Data System (ADS)

    Cucchiaro, A.; Anzidei, L.; Capriccioli, A.; Celentano, G.; Crescenzi, C.; Gasparotto, M.; Guerrieri, A.; Pizzuto, A.; Palmieri, A.; Rita, C.; Roccella, M.; Coppi, B.

    1998-11-01

    The structural performance of the IGNITOR machine relies upon a combination of both bucking between Toroidal Field Coils (TFCs), Central Solenoid (CS) and the Central Post (CP), and wedging in a well-defined area of the TFCs and of the magnet mechanical structure (called C-Clamps). This requires a pre-loading system to enhance the load bearing capability. Several solutions have been assessed and compared with each other within the operational scenarios and eventually a radial electromagnetic press has been selected as reference(Pizzuto A. et al., ENEA Report IGN/MAC/001/96). The loading system is made up by active coils and passive restraining rings. The radial active press consists of two pairs of coils (200x200mm each), symmetrically located relative to the machine equatorial plane and seating onto the passive rings. The permanent pre--load of the rings is applied through a wedging system with a load of about 120 MN. A radial electromagnetic press has the purpose of modulating the axial pressure on the TFC inner legs during the pulse. Design aspects including stress analysis, manufacturing, assembly and operational scenarios of the selected solution are presented in this paper.

  10. Electromagnetic scattering from buried objects

    SciTech Connect

    Brock, B.C.; Sorensen, K.W.

    1994-10-01

    Radar imaging and detection of objects buried in soil has potentially important applications in the areas of nonproliferation of weapons, environmental monitoring, hazardous-waste site location and assessment, and even archeology. In order to understand and exploit this potential, it is first necessary to understand how the soil responds to an electromagnetic wave, and how targets buried within the soil scatter the electromagnetic wave. We examine the response of the soil to a short pulse, and illustrate the roll of the complex dielectric permittivity of the soil in determining radar range resolution. This leads to a concept of an optimum frequency and bandwidth for imaging in a particular soil. We then propose a new definition for radar cross section which is consistent with the modified radar equation for use with buried targets. This radar cross section plays the same roll in the modified radar equation as the traditional radar cross section does in the free-space radar equation, and is directly comparable to it. The radar cross section of several canonical objects in lossy media is derived, and examples are given for several object/soil combinations.

  11. Electromagnetic signature of human cortical dynamics during wakefulness and sleep

    E-print Network

    Destexhe, Alain

    Electromagnetic signature of human cortical dynamics during wakefulness and sleep Signature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 2.5 Spatial reach of LFP & Electromagnetic Lead field . . . . . . . . . . . . . . . 35 2 Studies 45 4 Overview 47 4.1 Electromagnetic properties of the extracellular medium

  12. Electromagnetic Visibility and Invisibility Massachusetts Institute of Technology

    E-print Network

    Ciocan-Fontanine, Ionut

    Electromagnetic Visibility and Invisibility Ting Zhou Massachusetts Institute of Technology of determining the internal properties of a medium by mak- ing electromagnetic measurements at the boundary- neous isotropic electromagnetic background medium using the enclosure method. The second part

  13. AN ELECTROMAGNETIC INVERSE PROBLEM IN CHIRAL STEPHEN R. MCDOWALL

    E-print Network

    McDowall, Stephen

    AN ELECTROMAGNETIC INVERSE PROBLEM IN CHIRAL MEDIA STEPHEN R. MCDOWALL Abstract. We consider determines the electromagnetic parameters, namely the conductivity, electric permittivity, magnetic to the electromagnetic fields, the equations governing these fields change from a single second order elliptic partial

  14. Symmetries and currents of massless neutrino fields, electromagnetic and

    E-print Network

    Pohjanpelto, Juha

    Symmetries and currents of massless neutrino fields, electromagnetic interesting cases, are also presented in tensorial form for electromagnetic and graviton fields, respectively de- scribing neutrino fields, electromagnetic fields and graviton fields (i.e., linearized

  15. THE ELECTROMAGNETIC INVERSE SCATTERING PROBLEM FOR PARTIALLY COATED LIPSCHITZ DOMAINS

    E-print Network

    Cakoni, Fioralba

    THE ELECTROMAGNETIC INVERSE SCATTERING PROBLEM FOR PARTIALLY COATED LIPSCHITZ DOMAINS FIORALBA electromagnetic plane wave and the electric far field pattern of the scattered wave. A justification is given method. Key words. Electromagnetic inverse scattering, Lipschitz domain, mixed boundary conditions

  16. The Inverse Electromagnetic Scattering Problem for Anisotropic Media

    E-print Network

    Cakoni, Fioralba

    The Inverse Electromagnetic Scattering Problem for Anisotropic Media Fioralba Cakoni1 , David. The inverse electromagnetic scattering problem for anisotropic media plays a special role in inverse. Introduction The inverse electromagnetic scattering problem for anisotropic media plays a special role

  17. Cosmological electromagnetic fields due to gravitational wave perturbations Mattias Marklund*

    E-print Network

    Dunsby, Peter

    Cosmological electromagnetic fields due to gravitational wave perturbations Mattias Marklund of Electromagnetics, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden Peter K. S. Dunsby Department; published 9 October 2000 We consider the dynamics of electromagnetic fields in an almost

  18. Understanding stable levitation of superconductors from intermediate electromagnetics

    E-print Network

    Majós, Antonio Badķa

    Understanding stable levitation of superconductors from intermediate electromagnetics A. Bad for electromagnetic energy related quantities. Comprehensible illustrations, based on the calculated lines of magnetic at students who have followed an intermediate course on Electromagnetics and have some background in Classical

  19. NORTHWESTERN UNIVERSITY FDTD Computational Electromagnetics Modeling of Microcavity

    E-print Network

    Sheridan, Jennifer

    NORTHWESTERN UNIVERSITY FDTD Computational Electromagnetics Modeling of Microcavity Lasers FDTD Computational Electromagnetics Modeling of Microcavity Lasers and Resonant Optical Structures. Microcavity resonators have electromagnetic wave trans- port phenomena as a critical operating factor

  20. Electromagnetically Restrained Lithium Blanket APEX Interim Report November, 1999

    E-print Network

    California at Los Angeles, University of

    to avoid corrosion or fire. Lithium's high electrical conductivity may possibly permit efficient, compactElectromagnetically Restrained Lithium Blanket APEX Interim Report November, 1999 6-1 CHAPTER 6: ELECTROMAGNETICALLY RESTRAINED LITHIUM BLANKET Contributors Robert Woolley #12;Electromagnetically Restrained Lithium

  1. Electromagnetic Characterization of MIMO Communication Systems

    E-print Network

    Heath Jr., - Robert W.

    electromagnetic simulation method­ ology is proposed that accounts for both near­field and far­field interactionsElectromagnetic Characterization of MIMO Communication Systems Kapil R. Dandekar, Sumant Kawale communication has fueled interest in spectrum­ e#cient multiple­input multiple­output (MIMO) wireless

  2. Electromagnetic Characterization of MIMO Communication Systems

    E-print Network

    Dong, Liang

    electromagnetic simulation method- ology is proposed that accounts for both near-field and far-field interactionsElectromagnetic Characterization of MIMO Communication Systems Kapil R. Dandekar, Sumant Kawale communication has fueled interest in spectrum- efficient multiple-input multiple-output (MIMO) wireless

  3. Dielectric detection by an electromagnetic cavity method

    Microsoft Academic Search

    James C. Weatherall; Howard F. Beckley; Joseph A. Gatto

    2004-01-01

    A method to screen for flammable and explosive materials in bottles by electromagnetic measurement is described. The technique makes use of an aluminum cavity having strong electromagnetic resonances in the radio wave band. An object inserted into the cavity changes the internal field configuration, and causes small, but measurable shifts in the resonant frequencies. The response depends on the electrical

  4. Assessment and control of spacecraft electromagnetic interference

    NASA Technical Reports Server (NTRS)

    1972-01-01

    Design criteria are presented to provide guidance in assessing electromagnetic interference from onboard sources and establishing requisite control in spacecraft design, development, and testing. A comprehensive state-of-the-art review is given which covers flight experience, sources and transmission of electromagnetic interference, susceptible equipment, design procedure, control techniques, and test methods.

  5. Vibration Control System Using Electromagnetic Forces

    Microsoft Academic Search

    Yuji Matsuzaki; Daisuke Ishikubo; Toru Kamita; Tadashige Ikeda

    1997-01-01

    This paper presents the concept of a new vibration control system in which motions of an Al-Fe alloy thin beam\\/plate with magnetized segments can be suppressed or activated through electromagnetic forces induced by an applied electric current. Analytical evaluation of the induced electromagnetic forces acting both on the electric current applied and on the magnetized segments are derived from an

  6. Electromagnetic force density in a ferromagnetic material

    Microsoft Academic Search

    Franēois Henrotte; Hans Vande Sande; Geoffrey Deliége; Kay Hameyer

    2004-01-01

    Material derivatives for electromagnetic fields are presented. They are applied to determine the Maxwell stress tensor associated with different models of ferromagnetic materials. The accent is placed on the theoretical implications of the simplifying assumptions done in the different material models, with a thermodynamically consistent finite-element implementation of electromagnetic forces in scope.

  7. Himass electromagnetic launcher at Los Alamos

    SciTech Connect

    Zimmermann, E.L.; Fowler, C.M.; Foley, E.; Parker, J.V.

    1986-01-01

    The HIMASS electromagnetic launcher is a unique large-bore, large-mass railgun driven by a helical flux compression generator. Two experiments were conducted at 3 to 4 MA current levels. The objective of the experiments was to study the effects of scaling, ablation, and material parameters on electromagnetic launcher performance. Data from these two experiments are presented.

  8. Properties of Electromagnetic Field Focusing Probe

    Microsoft Academic Search

    William S. Yamanashi; Nabil A. Yassa; Deborah L. Hill; Angelo A. Patil; Patrick D. Lester

    1988-01-01

    The electromagnetic field focusing (EFF) apparatus consists of a radio fre quency generator, solenoidal coil, and a hand-held or catheter probe. Applica tions such as aneurysm treatment, angioplasty, and neurosurgery in various models have been reported. The probe is operated in the near field (within one wavelength of an electromagnetic field source) of a coil inducing eddy currents in biological

  9. Seismic and electromagnetic tunnel detection investigation

    Microsoft Academic Search

    H. F. Knauf

    1975-01-01

    This report describes the major areas of tunnel detection investigations conducted by USAMERDC during the period December 1966 through December 1969. A short discussion of the tunnel problem is presented, and two technical approaches, seismic and electromagnetic, are discussed. Both seismic and electromagnetic detector systems were developed and evaluation tests were conducted to determine capabilities and limitations of the devices.

  10. High-frequency seismo-electromagnetic effects

    Microsoft Academic Search

    M. Parrot; J. Achache; J. J. Berthelier; E. Blanc; A. Deschamps; F. Lefeuvre; M. Menvielle; J. L. Plantet; P. Tarits; J. P. Villain

    1993-01-01

    Electromagnetic perturbations caused by natural geophysical activity, such as earthquakes and volcanic eruptions, have been studied since the great Alaskan earthquake in 1964. In recent years, interest has been increasing because, when a precursor event occurs, it normally does so less than a few hours before the shock. This paper presents a review of the high-frequency seismo-electromagnetic phenomena already observed,

  11. Complete transformer model for electromagnetic transients

    Microsoft Academic Search

    F. de Leon; A. Semlyen

    1994-01-01

    A complete, three phase transformer model for the calculation of electromagnetic transients is presented. The model consists of a set of state equations solved with the trapezoidal rule of integration in order to obtain an equivalent Norton circuit at the transformer terminals. Thus the transformer model can be easily interfaced with an electromagnetic transients program. Its main features are: (a)

  12. NASA Applications for Computational Electromagnetic Analysis

    NASA Technical Reports Server (NTRS)

    Lewis, Catherine C.; Trout, Dawn H.; Krome, Mark E.; Perry, Thomas A.

    2011-01-01

    Computational Electromagnetic Software is used by NASA to analyze the compatibility of systems too large or too complex for testing. Recent advances in software packages and computer capabilities have made it possible to determine the effects of a transmitter inside a launch vehicle fairing, better analyze the environment threats, and perform on-orbit replacements with assured electromagnetic compatibility.

  13. Electromagnetic corrections to light hadron masses

    E-print Network

    A. Portelli; S. Dürr; Z. Fodor; J. Frison; C. Hoelbling; S. D. Katz; S. Krieg; T. Kurth; L. Lellouch; T. Lippert; K. K. Szabó; A. Ramos

    2011-01-12

    At the precision reached in current lattice QCD calculations, electromagnetic effects are becoming numerically relevant. We will present preliminary results for electromagnetic corrections to light hadron masses, based on simulations in which a $\\mathrm{U}(1)$ degree of freedom is superimposed on $N_f=2+1$ QCD configurations from the BMW collaboration.

  14. The Teaching of Electromagnetism at University Level

    ERIC Educational Resources Information Center

    Houldin, J. E.

    1974-01-01

    Discusses different kinds of material presentation in the teaching of electromagnetism at the university level, including three "classical" approaches and the Keller personalized proctorial system. Indicates that a general introduction to generators and motors may be useful in an electromagnetism course. (CC)

  15. Project Physics Tests 4, Light and Electromagnetism.

    ERIC Educational Resources Information Center

    Harvard Univ., Cambridge, MA. Harvard Project Physics.

    Test items relating to Project Physics Unit 4 are presented in this booklet. Included are 70 multiple-choice and 22 problem-and-essay questions. Concepts of light and electromagnetism are examined on charges, reflection, electrostatic forces, electric potential, speed of light, electromagnetic waves and radiations, Oersted's and Faraday's work,…

  16. Wavelets and electromagnetic power system transients

    Microsoft Academic Search

    D. C. Robertson; O. I. Camps; J. S. Mayer; W. B. Gish

    1996-01-01

    The wavelet transform is introduced as a method for analyzing electromagnetic transients associated with power system faults and switching. This method, like the fourier transform, provides information related to the frequency composition of a waveform, but it is more appropriate than the familiar Fourier methods for the non-periodic, wide-band signals associated with electromagnetic transients. It appears that the frequency domain

  17. Localization of fremions in rotating electromagnetic fields

    E-print Network

    B. V. Gisin

    2015-06-15

    Parameters of localization are defined in the lab and rotating frame for solutions of the Dirac equation in the field of a traveling circularly polarized electromagnetic wave and constant magnetic field. The radius of localization is of the order of the electromagnetic wavelength and lesser.

  18. The Good, the Bad and the Electromagnet

    NSDL National Science Digital Library

    STARS GK-12 Program,

    Using plastic straws, wire, batteries and iron nails, student teams build and test two versions of electromagnets—one with and one without an iron nail at its core. They test each magnet's ability pick up loose staples, which reveals the importance of an iron core to the magnet's strength. Students also learn about the prevalence and importance of electromagnets in their everyday lives.

  19. Electromagnetic Modelling of Superconducting Sensor Designs

    E-print Network

    Gerra, Guido

    DEPARTMENT OF MATERIALS SCIENCE AND METALLURGY Electromagnetic Modelling of Superconducting Sensor Designs Guido Gerra Clare Hall, University of Cambridge 1 Preface The present dissertation has been submitted... small changes in the current circulating in it to the magnetic field the SQUID is subjected to. This possibility arises from the dynamics of electromagnetic fields in superconductors combined with the Josephson effect, and appropriate coupling schemes...

  20. Upper High School Students' Understanding of Electromagnetism

    ERIC Educational Resources Information Center

    Saglam, Murat; Millar, Robin

    2006-01-01

    Although electromagnetism is an important component of upper secondary school physics syllabuses in many countries, there has been relatively little research on students' understanding of the topic. A written test consisting of 16 diagnostic questions was developed and used to survey the understanding of electromagnetism of upper secondary school…

  1. Electromagnetic Concepts in Mathematical Representation of Physics.

    ERIC Educational Resources Information Center

    Albe, Virginie; Venturini, Patrice; Lascours, Jean

    2001-01-01

    Addresses the use of mathematics when studying the physics of electromagnetism. Focuses on common electromagnetic concepts and their associated mathematical representation and arithmetical tools. Concludes that most students do not understand the significant aspects of physical situations and have difficulty using relationships and models specific…

  2. Space-time Curvature of Classical Electromagnetism

    E-print Network

    R. W. M. Woodside

    2004-10-08

    The space-time curvature carried by electromagnetic fields is discovered and a new unification of geometry and electromagnetism is found. Curvature is invariant under charge reversal symmetry. Electromagnetic field equations are examined with De Rham co homology theory. Radiative electromagnetic fields must be exact and co exact to preclude unobserved massless topological charges. Weyl's conformal tensor, here called ``the gravitational field'', is decomposed into a divergence-free non-local piece with support everywhere and a local piece with the same support as the matter. By tuning a local gravitational field to a Maxwell field the electromagnetic field's local gravitational field is discovered. This gravitational field carries the electromagnetic field's polarization or phase information, unlike Maxwell's stress-energy tensor. The unification assumes Einstein's equations and derives Maxwell's equations from curvature assumptions. Gravity forbids magnetic monopoles! This unification is stronger than the Einstein-Maxwell equations alone, as those equations must produce the electromagnetic field's local gravitational field and not just any conformal tensor. Charged black holes are examples. Curvature of radiative null electromagnetic fields is characterized.

  3. Time reversal of electromagnetic waves and telecommunication

    Microsoft Academic Search

    G. Lerosey; J. de Rosny; A. Tourin; A. Derode; G. Montaldo; M. Fink

    2005-01-01

    Time reversal (TR) communication in various configurations (single input, single output (SISO); multiple inputs, single output (MISO); or multiple inputs, multiple outputs (MIMO)) is studied. In particular, we report an experimental demonstration of time reversal focusing with electromagnetic waves in a SISO scheme. An antenna transmits a 1 ?s electromagnetic pulse at a central frequency of 2.45 GHz in a

  4. Electromagnetic vacuum fluctuations and electron coherence

    Microsoft Academic Search

    L. H. Ford

    1993-01-01

    The coupling of the quantized electromagnetic field to coherent electrons is investigated. The effects both of photon emission and of the electromagnetic vacuum fluctuations upon electron interference are analyzed. The modifications of the vacuum fluctuations due to a conducting plate lead to a decrease in the amplitude of the interference oscillations. The possibility of observing this effect is discussed. It

  5. Direct electromagnetic optimization of microwave filters

    Microsoft Academic Search

    S. Bila; D. Baillargeat; M. Aubourg; S. Verdeyme; P. Guillon; F. Seyfert; J. Grimm; L. Baratchart; C. Zanchi; J. Sombrin

    2001-01-01

    This article explores an optimization procedure for microwave filters and multiplexers. The procedure is initialized by a classical filter synthesis based on a segmented electromagnetic synthesis that provides the basic dimensions of the structure. The optimization loop, which combines a global electromagnetic analysis and a coupling identification, improves the structure response compared to an empirical optimization

  6. Electromagnetic field with constraints and Papapetrou equation

    E-print Network

    Z. Ya. Turakulov; A. T. Muminov

    2006-01-12

    It is shown that geometric optical description of electromagnetic wave with account of its polarization in curved space-time can be obtained straightforwardly from the classical variational principle for electromagnetic field. For this end the entire functional space of electromagnetic fields must be reduced to its subspace of locally plane monochromatic waves. We have formulated the constraints under which the entire functional space of electromagnetic fields reduces to its subspace of locally plane monochromatic waves. These constraints introduce variables of another kind which specify a field of local frames associated to the wave and contain some congruence of null-curves. The Lagrangian for constrained electromagnetic field contains variables of two kinds, namely, a congruence of null-curves and the field itself. This yields two kinds of Euler-Lagrange equations. Equations of first kind are trivial due to the constraints imposed. Variation of the curves yields the Papapetrou equations for a classical massless particle with helicity 1.

  7. Noninvasive valve monitor using alternating electromagnetic field

    DOEpatents

    Eissenberg, David M. (Oak Ridge, TN); Haynes, Howard D. (Knoxville, TN); Casada, Donald A. (Knoxville, TN)

    1993-01-01

    One or more electrical coils are carefully located on the outside of a valve body. An alternating current passing through the coil(s) results in an alternating electromagnetic field being transmitted into the valve body and valve internals. The electromagnetic field varies in intensity and polarity in the valve. As the position of a valve internal part is changed, the electromagnetic field throughout the valve body and its internals is altered. A passive receiver coil carefully located on the outside of the valve body detects the intensity of the electromagnetic field at that location as an induced electrical voltage in the coil. With the change in position of the valve internal part, there is a corresponding change in the induced voltage as a result of the alteration in the alternating electromagnetic field at that location. Changes in the voltage provide an indication of the position and motion of valve internals.

  8. Noninvasive valve monitor using alternating electromagnetic field

    DOEpatents

    Eissenberg, D.M.; Haynes, H.D.; Casada, D.A.

    1993-03-16

    One or more electrical coils are carefully located on the outside of a valve body. An alternating current passing through the coil(s) results in an alternating electromagnetic field being transmitted into the valve body and valve internals. The electromagnetic field varies in intensity and polarity in the valve. As the position of a valve internal part is changed, the electromagnetic field throughout the valve body and its internals is altered. A passive receiver coil carefully located on the outside of the valve body detects the intensity of the electromagnetic field at that location as an induced electrical voltage in the coil. With the change in position of the valve internal part, there is a corresponding change in the induced voltage as a result of the alteration in the alternating electromagnetic field at that location. Changes in the voltage provide an indication of the position and motion of valve internals.

  9. Charging Ahead: An Introduction to Electromagnetism

    NSDL National Science Digital Library

    Larry E. Schafer

    2001-01-01

    Charging Ahead: An Introduction to Electromagnetism is a set of hands-on activities designed to help teachers introduce middle and high school students to electromagnetism, one of the most fascinating and life changing phenomenon humankind has witnessed. In 1820, Hans Oersted, a Danish physicist and school teacher, discovered that an electrical current produces magnetism. This set the stage for the development of the electrical motor and generating electricity from motion and magnets. Charging Ahead uses readily available materials to introduce students to electromagnetism, to the factors that determine the strength of electrical coils, to the application of electromagnetism in the construction of an electrical motor, and to the production of electricity through the construction of a generator. Throughout the book, students are introduced to historical perspectives and to technological applications (circuit breakers, mag-lev trains, superconducting generators, etc.) of electromagnetism.

  10. Gravito-electromagnetic resonances in Minkowski space

    E-print Network

    Kouretsis, Alexandros P

    2013-01-01

    We consider the interaction between gravitational and electromagnetic radiation propagating on a Minkowski background and look into the effects of the former upon the latter. Not surprisingly, the coupling between these two sources leads to gravitationally driven electromagnetic waves. At the second perturbative level, the driving force appears as the superposition of two waves, the properties of which are decided by the initial conditions. We find that the Weyl-Maxwell interaction typically leads to electromagnetic beat-like signals and, in some cases, to the resonant amplification of the driven electromagnetic wave. For physically reasonable initial conditions, we show that these resonances imply a linear (in time) growth for the amplitude of the electromagnetic signal, with the overall amplification also depending on the strength of the driving gravity wave. Finally, we provide order-of-magnitude estimates of the achieved amplification by applying our analysis to astrophysical environments where both gravi...

  11. On electromagnetic and quantum invisibility

    NASA Astrophysics Data System (ADS)

    Mundru, Pattabhiraju Chowdary

    The principle objective of this dissertation is to investigate the fundamental properties of electromagnetic wave interactions with artificially fabricated materials i.e., metamaterials for application in advanced stealth technology called electromagnetic cloaking. The main goal is to theoretically design a metamaterial shell around an object that completely eliminates the dipolar and higher order multipolar scattering, thus making the object invisible. In this context, we developed a quasi-effective medium theory that determines the optical properties of multi-layered-composites beyond the quasi-static limit. The proposed theory exactly reproduces the far-field scattering/extinction cross sections through an iterative process in which mode-dependent quasi-effective impedances of the composite system are introduced. In the large wavelength limit, our theory is consistent with Maxwell-Garnett formalism. Possible applications in determining the hybridization particle resonances of multi-shell structures and electromagnetic cloaking are identified. This dissertation proposes a multi-shell generic cloaking system. A transparency condition independent of the object's optical and geometrical properties is proposed in the quasi-static regime of operation. The suppression of dipolar scattering is demonstrated in both cylindrically and spherically symmetric systems. A realistic tunable low-loss shell design is proposed based on the composite metal-dielectric shell. The effects due to dissipation and dispersion on the overall scattering cross-section are thoroughly evaluated. It is shown that a strong reduction of scattering by a factor of up to 103 can be achieved across the entire optical spectrum. Full wave numerical simulations for complex shaped particle are performed to validate the analytical theory. The proposed design does not require optical magnetism and is generic in the sense that it is independent of the object's material and geometrical properties. A generic quantum cloak analogous to the optical cloak is also proposed. The transparency conditions required for the shells to cloak an object impinged by a low energy beam of particles are derived. A realistic cloaking system with semiconductor material shells is studied.

  12. The electromagnetic momentum of static charge-current distributions

    E-print Network

    Jerrold Franklin

    2013-05-06

    The origin of electromagnetic momentum for general static charge-current distributions is examined. The electromagnetic momentum for static electromagnetic fields is derived by implementing conservation of momentum for the sum of mechanical momentum and electromagnetic momentum. The external force required to keep matter at rest during the production of the final static configuration produces the electromagnetic momentum. Examples of the electromagnetic momentum in static electric and magnetic fields are given. The `center of energy' theorem is shown to be violated by electromagnetic momentum. `Hidden momentum' is shown to be generally absent, and not to cancel electromagnetic momentum.

  13. Dressing the electromagnetic nucleon current

    SciTech Connect

    Haberzettl, H. [Center for Nuclear Studies, Department of Physics, George Washington University, Washington, DC 20052 (United States); Huang, F. [Department of Physics and Astronomy, University of Georgia, Athens, Georgia 30602 (United States); Nakayama, K. [Department of Physics and Astronomy, University of Georgia, Athens, Georgia 30602 (United States); Institut fuer Kernphysik and Juelich Center for Hadron Physics, Forschungszentrum Juelich, 52425 Juelich (Germany)

    2011-06-15

    A field-theory-based approach to pion photoproduction off the nucleon is used to derive a microscopically consistent formulation of the fully dressed electromagnetic nucleon current in an effective Lagrangian formalism. It is shown how the rigorous implementation of local gauge invariance at all levels of the reaction dynamics provides equations that lend themselves to practically manageable truncations of the underlying nonlinearities of the problem. The requirement of consistency also suggests a novel way of treating the pion photoproduction problem. Guided by a phenomenological implementation of gauge invariance for the truncated equations that has proved successful for pion photoproduction, an expression for the fully dressed nucleon current is given that satisfies the Ward-Takahashi identity for a fully dressed nucleon propagator as a matter of course. Possible applications include meson photo- and electroproduction processes, bremsstrahlung, Compton scattering, and ee{sup '} processes off nucleons.

  14. Electromagnetic braking for Mars spacecraft

    SciTech Connect

    Holt, A.C.

    1986-01-01

    Aerobraking concepts are being studied to improve performance and cost effectiveness of propulsion systems for Mars landers and Mars interplanetary spacecraft. Access to megawatt power levels (nuclear power coupled to high-storage inductive or capacitive devices) on a manned Mars interplanetary spacecraft may make feasible electromagnetic braking and lift modulation techniques which were previously impractical. Using pulsed microwave and magnetic field technology, potential plasmadynamic braking and hydromagnetic lift modulation techniques have been identified. Entry corridor modulation to reduce loads and heating, to reduce vertical descent rates, and to expand horizontal and lateral landing ranges are possible benefits. In-depth studies are needed to identify specific design concepts for feasibility assessments. Standing wave/plasma sheath interaction techniques appear to be promising. The techniques may require some tailoring of spacecraft external structures and materials. In addition, rapid response guidance and control systems may require the use of structurally embedded sensors coupled to expert systems or to artificial intelligence systems.

  15. Transient electromagnetic sounding for groundwater.

    USGS Publications Warehouse

    Fitterman, D.V.; Stewart, M.T.

    1986-01-01

    The feasibility of using the transient electromagnetic sounding (TS or TDEM) method for groundwater expoloration can be studied by means of numerical models. As examples of its applicability to groundwater exploration, we study 4 groundwater exploration problems; 1) mapping of alluvial fill and gravel zones over bedrock; 2) mapping of sand and gravel lenses in till; 3) detection of salt or brackish water interfaces in freshwater aquifers; and 4) determination of hydrostratigraphy. The TS method is best suited for locating conductive targets, and has very good vertical resolution. Unlike other sounding techniques where the receiver-transmitter array must be expanded to sound more deeply, the depth of investigation for the TS method is a function of the length of time the transient is recorded. -from Authors

  16. The CLAS Forward Electromagnetic Calorimeter

    SciTech Connect

    M. Amarian; Geram Asryan; Kevin Beard; Will Brooks; Volker Burkert; Tom Carstens; Alan Coleman; Raphael Demirchyan; Yuri Efremenko; Hovanes Egiyan; Kim Egiyan; Herb Funsten; Vladimir Gavrilov; Kevin L. Giovanetti; R.M. Marshall; Berhard Mecking; R.C. Minehart; H. Mkrtchan; Mavrik Ohandjanyan; Youri Sharabian; L.C. Smith; Stepan Stepanyan; W.A. Stephens; T.Y. Tung; Carl Zorn

    2001-05-01

    The CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab utilizes six iron-free superconducting coils to provide an approximately toroidal magnetic field. The six sectors are instrumented individually to form six independent spectrometers. The forward region (8deg < (theta) < 45deg) of each sector is equipped with a lead-scintillator electromagnetic sampling calorimeter (EC), 16 radiation lengths thick, using a novel triangular geometry with stereo readout. With its good energy and position resolution, the EC is used to provide the primary electron trigger for CLAS. It is also used to reject pions, reconstruct pi-0 and eta decays and detect neutrons, This paper treats the design, construction and performance of the calorimeter.

  17. Electromagnetic Calorimeter for Hades Experiment

    NASA Astrophysics Data System (ADS)

    Kugler, A.; Blume, C.; Czyžycki, W.; Epple, E.; Fabbietti, L.; Galatyuk, T.; Golubeva, M.; Guber, F.; Hlavį?, S.; Ivashkin, A.; Kajetanowic, M.; Kardan, B.; Koenig, W.; Lapidus, K.; Lisowski, E.; Pietraszko, J.; Reshetin, A.; Rost, A.; Salabura, P.; Sobolev, Y. G.; Svoboda, O.; Tlusty, P.; Traxler, M.

    2014-06-01

    Electromagnetic calorimeter (ECAL) is being developed to complement the dilepton spectrometer HADES currently operating at GSI Darmstadt, Germany. ECAL will enable the HADES@FAIR experiment to measure data on neutral meson production in heavy ion collisions at the energy range of 2-10 A GeV on the beam of future accelerator SIS100@FAIR. The calorimeter will also improve the electron-hadron separation and will as well be used for the detection of photons from strange resonances in elementary and heavy ion reactions. Calorimeter modules constructed of lead glass Cherenkov counter, photomultiplier, HV divider and optical fiber are described in the detail. Two prototypes of novel front-end electronics based on TRB3 are presented. A dedicated LED based system being developed to monitor the stability of the calorimeter during beamtime is introduced as well.

  18. Broadband cavity electromagnetically induced transparency

    SciTech Connect

    Wei Xiaogang [Department of Physics, Florida International University, Miami, Florida 33199 (United States); College of Physics, Jilin University, Changchun 130023 (China); Wang Yanhua [Department of Physics, Florida International University, Miami, Florida 33199 (United States); College of Physics and Electronics, Shanxi University, Taiyuan 030006 (China); Zhang Jiepeng [Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071 (China); Physics Division P-23, Los Alamos National Laboratory, Los Alamos, New Mexico 87544 (United States); Zhu Yifu [Department of Physics, Florida International University, Miami, Florida 33199 (United States)

    2011-10-15

    Cavity electromagnetically induced transparency (EIT) is created in a three-level atomic system confined in a cavity and coupled to a free-space control laser and is manifested as a narrow transmission peak of a probe laser coupled into the cavity mode and tuned to the two-photon Raman resonance with the control laser. Cavity EIT can be observed with a control laser detuned from the atomic transition frequency in a range limited by the vacuum Rabi splitting of two cavity-atom normal modes. This leads to the broadband cavity EIT obtained in the coupled-cavity-atom system with a free-space, broadband control laser. We report an experimental observation of broadband cavity EIT in cold Rb atoms with a frequency-modulated control laser and discuss its application in multichannel and multifrequency light memory.

  19. Electromagnetic Signatures of SMBH Coalescence

    NASA Technical Reports Server (NTRS)

    Schnittman, Jeremy

    2012-01-01

    When two supermassive black holes (SMBHs) approach within 1-10 mpc, gravitational wave (GW) losses begin to dominate the evolution of the binary, pushing the system to merge in a relatively small time. During this final inspiral regime, the system will emit copious energy in GWs, which should be directly detectable by pulsar timing arrays and space-based interferometers. At the same time, any gas or stars in the immediate vicinity of the merging 5MBHs can get heated and produce bright electromagnetic (EM) counterparts to the GW signals. We present here a number of possible mechanisms by which simultaneous EM and GW signals will yield valuable new information about galaxy evolution, accretion disk dynamics, and fundamental physics in the most extreme gravitational fields.

  20. Tracking Electromagnetic Energy With SQUIDs

    NASA Technical Reports Server (NTRS)

    2005-01-01

    A superconducting quantum interference device (SQUID) is a gadget used to measure extremely weak signals, specifically magnetic flux. It can detect subtle changes in energy, up to 100 billion times weaker than the electromagnetic energy required to move a compass needle. SQUIDs are used for a variety of testing procedures where extreme sensitivity is required and where the test instrument need not come into direct contact with the test subject. NASA uses SQUIDs for remote, noncontact sensing in a variety of venues, including monitoring the Earth s magnetic field and tracking brain activity of pilots. Scientists at NASA s Goddard Space Flight Center have been making extensive use of this technology, from astrophysical research, to tracking the navigational paths of bees in flight to determine if they are using internal compasses. These very sensitive measurement devices have a wide variety of uses within NASA and even more uses within the commercial realm.

  1. Electromagnetic modeling of plasmonic nanostructures

    NASA Astrophysics Data System (ADS)

    Pavaskar, Prathamesh

    In this thesis, plasmonic properties of metal nanostructures are investigated by electromagnetic simulations using the finite difference time domain (FDTD) method. Chapter 1 covers the background knowledge required to read this thesis. It talks about the fundamentals of the FDTD method, the physics of plasmonics and a brief description of photocatalysis. In chapter 2, we perform optimization of plasmonic nanoparticle geometries. An iterative optimization algorithm is used to determine the configuration of the nanoparticles that gives the maximum electric field intensity at the center of the cluster. We observe that the optimum configurations of these clusters have mirror symmetry about the axis of planewave propagation, but are otherwise non-symmetric and non-intuitive. The maximum field intensity is found to increase monotonically with the number nanoparticles in the cluster, producing intensities that are 2500 times larger than the incident electromagnetic field. In chapter 3, evaporated thin films are imaged with high resolution transmission electron microscopy (HRTEM), to reveal the structure of the semicontinuous metal island film with sub-nm resolution. The electric field distributions and the absorption spectra of these semicontinuous island film geometries are calculated using the finite difference time domain (FDTD) method and compared with the experimentally measured absorption spectra. In addition to that, we calculate the SERS enhancement factors and photocatalytic enhancement factors of these films. We also study the effect of annealing on these films, which results in a large reduction in electric field strength due to increased nanoparticle spacing. In chapter 4, we study the effects of surrounding nanoparticles on a plasmonic hot spot. From our simulations, we show that the surrounding film contributes significantly to the electric field intensity at the hot spot by focusing energy to it. Widening of the gap size causes a decrease in the intensity at the hot spot. However, these island-like nanoparticle hot spots are shown to be robust to gap size than nanoparticle dimer geometries, studied previously. In fact, the main factor in determining the hot spot intensity is the focusing effect of the surrounding nano-islands. In chapter 5, we demonstrate plasmon-enhanced photocatalytic water splitting, and reduction of CO2 with H2O to form hydrocarbon fuels. Under visible illumination, we observe enhancements of up to 66X in the photocatalytic splitting of water in TiO2 with the addition of Au nanoparticles. We also perform a systematic study of the mechanisms of Au nanoparticle/TiO 2-catalyzed photoreduction of CO2 and water vapor over a wide range of wavelengths. In this case, under visible light illumination, we observe a 24-fold enhancement in the photocatalytic activity due to the intense local electromagnetic fields created by the surface plasmons of the Au nanoparticles. Above the plasmon resonance, under ultraviolet radiation we observe a reduction in the photocatalytic activity. Electromagnetic simulations indicate that the improvement of photocatalytic activity in the visible range is caused by the local electric field enhancement near the TiO2 surface, rather than by the direct transfer of charge between the two materials. In chapter 6, I will talk about a method for fabricating arrays of plasmonic nanoparticles with separations on the order of 1nm using an angle evaporation technique. High resolution transmission electron microscopy (HRTEM) is used to resolve the small separations achieved between nanoparticles fabricated on thin SiN membranes. These nearly touching metal nanoparticles produce extremely high electric field intensities when irradiated with laser light. We perform surface enhanced Raman spectroscopy (SERS) a non-resonant dye molecule (p-ATP) deposited on the nanoparticle arrays using confocal micro-Raman spectroscopy. Our results show significant enhancement when the incident laser is polarized parallel to the axis of the nanoparticle pairs, whereas no enhancement is observed for the p

  2. Electromagnetic scattering by impedance structures

    NASA Technical Reports Server (NTRS)

    Balanis, Constantine A.; Griesser, Timothy

    1987-01-01

    The scattering of electromagnetic waves from impedance structures is investigated, and current work on antenna pattern calculation is presented. A general algorithm for determining radiation patterns from antennas mounted near or on polygonal plates is presented. These plates are assumed to be of a material which satisfies the Leontovich (or surface impedance) boundary condition. Calculated patterns including reflection and diffraction terms are presented for numerious geometries, and refinements are included for antennas mounted directly on impedance surfaces. For the case of a monopole mounted on a surface impedance ground plane, computed patterns are compared with experimental measurements. This work in antenna pattern prediction forms the basis of understanding of the complex scattering mechanisms from impedance surfaces. It provides the foundation for the analysis of backscattering patterns which, in general, are more problematic than calculation of antenna patterns. Further proposed study of related topics, including surface waves, corner diffractions, and multiple diffractions, is outlined.

  3. Exponential beams of electromagnetic radiation

    E-print Network

    Bialynicki-Birula, I; Bialynicki-Birula, Iwo; Bialynicka-Birula, Zofia

    2006-01-01

    We show that in addition to well known Bessel, Hermite-Gauss, and Laguerre-Gauss beams of electromagnetic radiation, one may also construct exponential beams. These beams are characterized by a fall-off in the transverse direction described by an exponential function of rho. Exponential beams, like Bessel beams, carry definite angular momentum and are periodic along the direction of propagation, but unlike Bessel beams they have a finite energy per unit beam length. The analysis of these beams is greatly simplified by an extensive use of the Riemann-Silberstein vector and the Whittaker representation of the solutions of the Maxwell equations in terms of just one complex function. The connection between the Bessel beams and the exponential beams is made explicit by constructing the exponential beams as wave packets of Bessel beams.

  4. An electromagnetic black hole made of metamaterials

    E-print Network

    Qiang Cheng; Tie Jun Cui; Wei Xiang Jiang; Ben Geng Cai

    2010-04-30

    Traditionally, a black hole is a region of space with huge gravitational field, which absorbs everything hitting it. In history, the black hole was first discussed by Laplace under the Newton mechanics, whose event horizon radius is the same as the Schwarzschild's solution of the Einstein's vacuum field equations. If all those objects having such an event horizon radius but different gravitational fields are called as black holes, then one can simulate certain properties of the black holes using electromagnetic fields and metamaterials due to the similar propagation behaviours of electromagnetic waves in curved space and in inhomogeneous metamaterials. In a recent theoretical work by Narimanov and Kildishev, an optical black hole has been proposed based on metamaterials, in which the theoretical analysis and numerical simulations showed that all electromagnetic waves hitting it are trapped and absorbed. Here we report the first experimental demonstration of such an electromagnetic black hole in the microwave frequencies. The proposed black hole is composed of non-resonant and resonant metamaterial structures, which can trap and absorb electromagnetic waves coming from all directions spirally inwards without any reflections due to the local control of electromagnetic fields and the event horizon corresponding to the device boundary. It is shown that the absorption rate can reach 99% in the microwave frequencies. We expect that the electromagnetic black hole could be used as the thermal emitting source and to harvest the solar light.

  5. Mass continuity equation in the electromagnetic field

    E-print Network

    Ying Weng; Zi-Hua Weng

    2009-09-07

    A theoretical method with the quaternion algebra was presented to derive the mass continuity equation from the linear momentum. It predicts that the strength of electromagnetic field and the velocity have the impact on the mass continuity equation. In the gravitational field and electromagnetic field, the mass continuity equation will change with the electromagnetic field strength, gravitational field strength, linear momentum, electric current, and the speed of light. The deduction can explain why the field strength has an influence on the anomalous transport about the mass continuity equation in the plasma and electrolytes etc.

  6. Counting energy packets in the electromagnetic wave

    E-print Network

    Stefan Popescu; Bernhard Rothenstein

    2007-05-18

    We discuss the concept of energy packets in respect to the energy transported by electromagnetic waves and we demonstrate that this physical quantity can be used in physical problems involving relativistic effects. This refined concept provides results compatible to those obtained by simpler definition of energy density when relativistic effects apply to the free electromagnetic waves. We found this concept further compatible to quantum theory perceptions and we show how it could be used to conciliate between different physical approaches including the classical electromagnetic wave theory, the special relativity and the quantum theories.

  7. Scattering by an electromagnetic radiation field

    E-print Network

    Donato Bini; Andrea Geralico

    2014-08-21

    Motion of test particles in the gravitational field associated with an electromagnetic plane wave is investigated. The interaction with the radiation field is modeled by a force term {\\it \\`a la} Poynting-Robertson entering the equations of motion given by the 4-momentum density of radiation observed in the particle's rest frame with a multiplicative constant factor expressing the strength of the interaction itself. Explicit analytical solutions are obtained. Scattering of fields by the electromagnetic wave, i.e., scalar (spin 0), massless spin $\\frac12$ and electromagnetic (spin 1) fields, is studied too.

  8. On the Axioms of Topological Electromagnetism

    E-print Network

    D. H. Delphenich

    2003-12-14

    The axioms of topological electromagnetism are refined by the introduction of the de Rham homology of k-vector fields on orientable manifolds and the use of Poincare duality in place of Hodge duality. The central problem of defining the electromagnetic constitutive law is elaborated upon in the linear and nonlinear cases. The manner by which the spacetime metric might follow from the constitutive law is examined in the linear case. The possibility that the intersection form of the spacetime manifold might play a role in defining a topological basis for the constitutive law is explored. The manner by which wave motion might follow from the electromagnetic structure is also discussed.

  9. Spinors and pre-metric electromagnetism

    E-print Network

    David Delphenich

    2005-12-22

    The basic concepts of the formulation of Maxwellian electromagnetism in the absence of a Minkowski scalar product on spacetime are summarized, with particular emphasis on the way that the electromagnetic constitutive law on the space of bivectors over spacetime supplants the role of the Minkowski scalar product on spacetime itself. The complex geometry of the space of bivectors is summarized, with the intent of showing how an isomorphic copy of the Lorentz group appears in that context. The use of complex 3-spinors to represent electromagnetic fields is then discussed, as well as the expansion of scope that the more general complex projective geometry of the space of bivectors suggests.

  10. Electromagnetics in high-{Tc} superconductors

    SciTech Connect

    Ma, J.G.; Wolff, I. [Gerhard-Mercator Univ., Duisburg (Germany). Dept. of Electrical Engineering

    1996-04-01

    The behavior of electromagnetic fields in high-{Tc} superconductors (HTS`s) is studied in order to examine their effects in classical electromagnetic boundary value problems. It is shown that an HTS can not be simply treated as a low loss conductor and boundary conditions of HTS`s can not be considered as perfect conducting boundaries like conventional treatments. The electromagnetics of HTS are investigated in terms of complex conductivity, surface impedance with applied magnetic fields, and computational electrodynamics using the new proposed model in Ref. 1.

  11. Varying Electromagnetic Coupling and Primordial Magnetic Fields

    E-print Network

    O. Bertolami; R. Monteiro

    2005-04-08

    We study the effect of variations of the electromagnetic coupling on the process of generation of primordial magnetic fields. We find that only through a significant growth of the electromagnetic coupling minimum seed fields can be produced. We also show that, if through some process in the early Universe the photon acquires a mass that leads, thanks to inflation, to the generation of primordial magnetic fields, then the influence of variations of the electromagnetic coupling amounts essentially to the results due to the photon effective mass alone.

  12. Development of a strong electromagnet wiggler

    SciTech Connect

    Burns, M.J.; Deis, G.A.; Holmes, R.H.; Van Maren, R.D.; Halbach, K.

    1987-01-01

    The Strong Electromagnet (SEM) wiggler is a permanent magnet-assisted electromagnet under development at the Lawrence Livermore National Laboratory (LLNL) as part of the Induction Linac Free-Electron-Laser (IFEL) program. This concept uses permanent magnets within the wiggler to provide a reverse bias flux in the iron and thus delay the onset of magnetic saturation. The electromagnet coils determine the wiggler field and operate at low current densities by virtue of their placement away from the midplane. We describe here the design approach used and test data from a 7-period wiggler prototype that includes curved pole tips to provide wiggle-plane focusing. 7 refs.

  13. Electromagnetic Properties for Arbitrary Spin Particles: Part 1 $-$ Electromagnetic Current and Multipole Decomposition

    E-print Network

    Cédric Lorcé

    2009-01-27

    In a set of two papers, we propose to study an old-standing problem, namely the electromagnetic interaction for particles of arbitrary spin. Based on the assumption that light-cone helicity at tree level and $Q^2=0$ should be conserved non-trivially by the electromagnetic interaction, we are able to derive \\emph{all} the natural electromagnetic moments for a pointlike particle of \\emph{any} spin. In this first paper, we propose a transparent decomposition of the electromagnetic current in terms of covariant vertex functions. We also define in a general way the electromagnetic multipole form factors, and show their relation with the electromagnetic moments. Finally, by considering the Breit frame, we relate the covariant vertex functions to multipole form factors.

  14. Reformulation of electromagnetic and gravito-electromagnetic equations for Lorentz system with octonion algebra

    NASA Astrophysics Data System (ADS)

    Tan??l?, Murat; Kansu, Mustafa Emre; Demir, Süleyman

    2014-05-01

    In this paper, the real, complex octonion algebra and their properties are defined. The electromagnetic and gravito-electromagnetic equations with monopoles in terms of S and reference systems are presented in vector notations. Additionally, the duality transformations of gravito-electromagnetic situation for two reference systems are also represented. Besides, it is explained that Maxwell-like equations for gravito-electromagnetism are also invariant under Lorentz transformations. By introducing complex octonionic differential operator, a new generalized complex octonionic field term consisting of electromagnetic and gravito-electromagnetic components has been firstly suggested for Lorentz system. Afterwards, a complex octonionic source equation is obtained as in basic way, more compact and elegant notation. By defining a new complex octonionic general potential term, the field equation is attained once again. The components of complex octonionic field and wave equations are written in detailed for S and reference systems.

  15. Application of electromagnetic force to run out table

    Microsoft Academic Search

    Keisuke Fujisaki

    2000-01-01

    The electromagnetic application system to improve the running characteristics at the run out table of a hot strip mill in a steel making plant by means of an electromagnetic force is proposed. According to fundamental analyses such as electromagnetic calculation and experimental data, this system is applicable to online operation, even with consideration of magnetic saturation and electromagnetic braking

  16. Realizability conditions for electromagnetic Gaussian Schell-model sources

    Microsoft Academic Search

    Hema Roychowdhury; Olga Korotkova

    2005-01-01

    The electromagnetic Gaussian Schell-model (EGSM) beam is the simplest analytical model of a random electromagnetic beam. The model can be successfully used in studies of spectral, polarization and coherence properties of random electromagnetic beams on propagation in free space or in any linear medium, deterministic or random. The most general type of source which produces electromagnetic Gaussian Schell-model beam is

  17. ECE 1228 Electromagnetics Theory Instructor Name: Mo Mojahedi

    E-print Network

    Mojahedi, Mohammad

    : 416-978-0908 Email: mojahedi@waves.utoronto.ca Course Name and number: Electromagnetics Theory, ECE in Electromagnetics and Photonics. It revisits and expands some of the more fundamental electromagnetic laws of electromagnetic theory and the dynamics of wave propagation and interaction with materials and structures. Topics

  18. PHYS 4500, Winter 2014 1 Electromagnetic Fields II

    E-print Network

    Quirion, Guy

    PHYS 4500, Winter 2014 1 PHYS 4500 Electromagnetic Fields II 1. What is this course all about's theorem, reflection and transmission of electromagnetic waves, cavity resonators, wave guides. Electromagnetic Radiation: dipoles, antennas, quantum mechanics and electro-magnetic interactions. 2. Textbook

  19. Title: Inverse Electromagnetic Problems Name: Gunther Uhlmann, Ting Zhou

    E-print Network

    Uhlmann, Gunther

    Title: Inverse Electromagnetic Problems Name: Gunther Uhlmann, Ting Zhou Affil./Addr. 1: University/University of California Irvine/tzhouuw@gmail.com Inverse Electromagnetic Problems Introduction In this chapter we consider inverse boundary problems for electromagnetic waves. The goal is to determine the electromagnetic

  20. Dynamic programming applied to electromagnetic satellite actuation

    E-print Network

    Eslinger, Gregory John

    2013-01-01

    Electromagnetic formation flight (EMFF) is an enabling technology for a number of space mission architectures. While much work has been done for EMFF control for large separation distances, little work has been done for ...

  1. FMM Code Libraries for Computational Electromagnetics

    E-print Network

    Maryland at College Park, University of

    Max Optics, Inc. #12;MadMax Optics 2 · Stealth · Electromagnetic interference · Antennas on complex platforms (ships/aircraft) · Packaging, mixed-signal analysis · Wideband antennas · etc. #12;MadMax Optics 3 · Fast

  2. Tabletop Models for Electrical and Electromagnetic Geophysics.

    ERIC Educational Resources Information Center

    Young, Charles T.

    2002-01-01

    Details the use of tabletop models that demonstrate concepts in direct current electrical resistivity, self-potential, and electromagnetic geophysical models. Explains how data profiles of the models are obtained. (DDR)

  3. Electromagnetic Fields and Public Health: Mobile Phones

    MedlinePLUS

    ... sheets Features Commentaries Multimedia Contacts Electromagnetic fields and public health: mobile phones Fact sheet N°193 Reviewed October ... important to investigate, understand and monitor any potential public health impact. Mobile phones communicate by transmitting radio waves ...

  4. Avionics electromagnetic interference immunity and environment

    NASA Technical Reports Server (NTRS)

    Clarke, C. A.

    1986-01-01

    Aircraft electromagnetic spectrum and radio frequency (RF) field strengths are charted, profiling the higher levels of electromagnetic voltages encountered by the commercial aircraft wiring. Selected military, urban, and rural electromagnetic field levels are plotted and provide a comparison of radiation amplitudes. Low frequency magnetic fields and electric fields from 400 H(Z) power systems are charted versus frequency and wire separation to indicate induced voltages on adjacent or neighboring circuits. Induced EMI levels and attenuation characteristics of electric, magnetic, RF fields, and transients are plotted and graphed for common types of wire circuits. The significance of wire circuit returns and shielding is emphasized to highlight the techniques that help block the paths of electromagnetic interference and maintain avionic interface signal quality.

  5. High transients suppressed in electromagnetic devices

    NASA Technical Reports Server (NTRS)

    Marion, C. W.

    1967-01-01

    A bifilar winding around the magnetic core of electromagnetic devices suppresses high transient voltages. The winding is alternately spaced vertically and radially from the core to achieve a high coefficient of coupling.

  6. Tour of the Electromagnetic Spectrum Booklet

    NSDL National Science Digital Library

    Troy Benesch

    2010-01-01

    This booklet introduces electromagnetic waves, their behaviors, and how scientists visualize these data. Each region of the spectrum is described and illustrated with examples of NASA science. It is a companion piece to the video series under the same title.

  7. Progress In Electromagnetics Research Symposium (PIERS)

    NASA Technical Reports Server (NTRS)

    1993-01-01

    The third Progress In Electromagnetics Research Symposium (PIERS) was held 12-16 Jul. 1993, at the Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California. More than 800 presentations were made, and those abstracts are included in this publication.

  8. Electromagnetic ion/ion cyclotron instability

    SciTech Connect

    Winske, D.; McKean, M.E. (Los Alamos National Lab., NM (USA)); Omidi, N.; Chou, V. (California Univ., San Diego, CA (USA))

    1991-01-01

    Linear analysis and hybrid simulations are used to investigate the properties of a new electromagnetic ion beam instability. Some applications of the instability in space are also discussed. 7 refs., 1 fig.

  9. Galium Electromagnetic (GEM) Thruster Concept and Design

    NASA Technical Reports Server (NTRS)

    Polzin, Kurt A.; Markusic, Thomas E.

    2005-01-01

    We describe the design of a new type of two-stage pulsed electromagnetic accelerator, the gallium electromagnetic (GEM) thruster. A schematic illustration of the GEM thruster concept is given. In this concept, liquid gallium propellant is pumped into the first stage through a porous metal electrode using an electromagnetic pump. At a designated time, a pulsed discharge (approx. 10-50 J) is initiated in the first stage, ablating the liquid gallium from the porous electrode surface and ejecting a dense thermal gallium plasma into the second state. The presence of the gallium plasma in the second stage serves to trigger the high-energy (approx. 500 J), second-stage pulse which provides the primary electromagnetic (j x B) acceleration.

  10. Electromagnetic wave analogue of electronic diode

    E-print Network

    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.

  11. Advances in non-planar electromagnetic prototyping

    E-print Network

    Ehrenberg, Isaac M

    2013-01-01

    The advent of metamaterials has introduced new ways to manipulate how electromagnetic waves reflect, refract and radiate in systems where the range of available material properties now includes negative permittivity, ...

  12. Calculation of electromagnetic force in electromagnetic forming process of metal sheet

    SciTech Connect

    Xu Da; Liu Xuesong; Fang Kun; Fang Hongyuan [State Key Laboratory of Advanced Welding Production Technology, Harbin Institute of Technology, Harbin 150001 (China)

    2010-06-15

    Electromagnetic forming (EMF) is a forming process that relies on the inductive electromagnetic force to deform metallic workpiece at high speed. Calculation of the electromagnetic force is essential to understand the EMF process. However, accurate calculation requires complex numerical solution, in which the coupling between the electromagnetic process and the deformation of workpiece needs be considered. In this paper, an appropriate formula has been developed to calculate the electromagnetic force in metal work-piece in the sheet EMF process. The effects of the geometric size of coil, the material properties, and the parameters of discharge circuit on electromagnetic force are taken into consideration. Through the formula, the electromagnetic force at different time and in different positions of the workpiece can be predicted. The calculated electromagnetic force and magnetic field are in good agreement with the numerical and experimental results. The accurate prediction of the electromagnetic force provides an insight into the physical process of the EMF and a powerful tool to design optimum EMF systems.

  13. Advances in electromagnetic brain imaging

    NASA Astrophysics Data System (ADS)

    Nagarajan, Srikantan S.

    2010-02-01

    Non-invasive and dynamic imaging of brain activity in the sub-millisecond time-scale is enabled by measurements on or near the scalp surface using an array of sensors that measure magnetic fields (magnetoencephalography (MEG)) or electric potentials (electroencephalography (EEG)). Algorithmic reconstruction of brain activity from MEG and EEG data is referred to as electromagnetic brain imaging (EBI). Reconstructing the actual brain response to external events and distinguishing unrelated brain activity has been a challenge for many existing algorithms in this field. Furthermore, even under conditions where there is very little interference, accurately determining the spatial locations and timing of brain sources from MEG and EEG data is challenging problem because it involves solving for unknown brain activity across thousands of voxels from just a few sensors (~300). In recent years, my research group has developed a suite of novel and powerful algorithms for EBI that we have shown to be considerably superior to existing benchmark algorithms. Specifically, these algorithms can solve for many brain sources, including sources located far from the sensors, in the presence of large interference from unrelated brain sources. Our algorithms efficiently model interference contributions to sensors, accurately estimate sparse brain source activity using fast and robust probabilistic inference techniques. Here, we review some of these algorithms and illustrate their performance in simulations and real MEG/EEG data.

  14. Parallel computation of electromagnetic fields

    SciTech Connect

    Madsen, N.K.

    1997-05-21

    The DSI3D code is designed to numerically solve electromagnetics problems involving complex objects by solving Maxwell`s curl equations in the time-domain and in three space dimensions. The code has been designed to run on the new parallel processing computers as well as on conventional serial computers. The DSI3D code is unique for the following reasons: It runs efficiently on a variety of parallel computers, Allows the use of unstructured non-orthogonal grids, Allows a variety of cell or element types, Reduces to be the Finite Difference Time Domain (FDID) method when orthogonal grids are used, Preserves charge or divergence locally (and globally), Is non- dissipative, and Is accurate for non-orthogonal grids. This method is derived using a Discrete Surface Integration (DSI) technique. As formulated, the DSI technique can be used with essentially arbitrary unstructured grids composed of convex polyhedral cells. This implementation of the DSI algorithm allows the use of unstructured grids that are composed of combinations of non-orthogonal hexahedrons, tetrahedrons, triangular prisms and pyramids. This algorithm reduces to the conventional FDTD method when applied on a structured orthogonal hexahedral grid.

  15. Cellular effects of electromagnetic fields.

    PubMed

    Naarala, Jonne; Höytö, Anne; Markkanen, Ari

    2004-10-01

    Studies at the cellular level are needed to reveal the cellular and molecular biological mechanisms underlying the biological effects and possible health implications of non-ionising radiation, such as extremely low frequency (ELF) magnetic fields (MFs) and radiofrequency (RF) fields. Our research group has studied the effects of 50 Hz ELF MFs (caused by power lines and electric devices) and 872 MHz or 900 MHz RFs (emitted by mobile phones and their base stations) on cellular ornithine decarboxylase activity, cell cycle kinetics, cell proliferation, and necrotic or apoptotic cell death. For RFs, pulse-modulated (217 Hz modulation frequency corresponding a global system for mobile communication-type signal) or continuous wave (unmodulated) signals were used. To expose the cell cultures to MFs or RFs, specially developed exposure systems were used, where levels of electromagnetic field exposure and the conditions of cell culture could be precisely controlled. A coexposure approach was used in many studies, i.e. the cell cultures were exposed to other stressors in addition to MFs or RFs. Ultraviolet radiation, serum deprivation, or fresh medium addition, were used as co-exposures. The results presented in this short review show that the effects of mere MFs or RF on cell culture models are quite minor, but that various co-exposure approaches warrant additional study. PMID:15651919

  16. Electromagnetic radiation from microwave ovens.

    PubMed

    Alhekail, Z O

    2001-09-01

    Electromagnetic radiation from microwave ovens in Saudi Arabia was investigated by means of a field measurement survey. The survey was carried out for 106 ovens used in households and restaurants in Riyadh city. Ovens were between 1 month and 14 years old with operating power ranging from 0.5 to 4.4 kW. One oven was found to leak more than the 5 mW cm(-2) limit specified in the standard. Fifteen other ovens were found to leak 1 mW cm(-2) or more, with the remaining ovens leaking less than that. Based on the survey result, previous studies and the fast decay of radiated power density with distance from the oven, the conclusion was that user exposure to RF radiation from microwave ovens is much less than the general public exposure limit set by most international standards at 2450 MHz, i.e. 1 mW cm(-2), and that a detrimental effect on health is an unlikely result of exposure to radiation from microwave ovens. PMID:11594651

  17. Medical applications of electromagnetic fields

    NASA Astrophysics Data System (ADS)

    Lai, Henry C.; Singh, Narendra P.

    2010-04-01

    In this article, we describe two possible applications of low-intensity non-ionizing electromagnetic fields (EMF) for the treatment of malaria and cancer, respectively. In malaria treatment, a low-intensity extremely-low frequency magnetic field can be used to induce vibration of hemozoin, a super-paramagnetic polymer particle, inside malaria parasites. This disturbance could cause free radical and mechanical damages leading to the death of the parasite. This concept has been tested in vitro on malaria parasites and found to be effective. This may provide a low cost effective treatment for malaria infection in humans. The rationale for cancer treatment using low-intensity EMF is based on two concepts that have been well established in the literature: (1) low-intensity non-thermal EMF enhances cytotoxic free radicals via the iron-mediated Fenton reaction; and (2) cancer cells have higher amounts of free iron, thus are more susceptible to the cytotoxic effects of EMF. Since normal cells contain minimal amount of free iron, the effect would be selectively targeting cancer cells. Thus, no adverse side effect would be expected as in traditional chemotherapy and radiation therapy. This concept has also been tested on human cancer cell and normal cells in vitro and proved to be feasible.

  18. An axial flux electromagnetic micromotor

    NASA Astrophysics Data System (ADS)

    Yang, Chunsheng; Zhao, Xiaolin; Ding, Guifu; Zhang, Chen; Cai, Bingchu

    2001-03-01

    In this paper, the principle, design, fabrication and performance of an axial flux electromagnetic micromotor are described. The stator of the micromotors consists of six levels of copper windings and an alumina filling using a modified LIGA (Lithographic Galvanoforming Abforming)-like technology. The rotor is a disc made of SmCo permanent magnetic alloy using the electro discharge machining (EDM) technique and it is magnetized with pairs of magnetic poles using a specially designed apparatus. The rotor and the stator are assembled together to form the micromotor. The dimensions of the assembled motors are 1 mm and 2 mm in diameter and about 1.5 mm thick. The rotation speed of the micromotors can be adjusted from several hundreds to over ten thousand rpm and the rotation is reversible. The output torques of the micromotor are measured to be 1.5 µN m and 2.8 µN m for motors with diameters of 1 mm and 2 mm, respectively.

  19. Control of Flow Separation Using Electromagnetic Forces

    Microsoft Academic Search

    Tom Weier; Gunther Gerbeth; Gerd Mutschke; Olgerts Lielausis; Gerd Lammers

    2003-01-01

    If a fluid is electrically conductive, its flow may be controlled using electromagnetic forces. Meanwhile, this technique\\u000a is a recognized tool even on an industrial scale for handling highly conductive materials like liquid metals. However, also\\u000a fluids of low electrical conductivity as considered in the present study, like sea-water and other electrolytes, permit electromagnetic\\u000a flow control. Experimental results on the

  20. CALCULATIONS OF THE ELECTROMAGNETIC FORCE IN RAILGUNS

    Microsoft Academic Search

    Jaime Taylor; Dennis Keefer

    1993-01-01

    Recent experiments in the UTSI 2.4 m railgun have led us to reexamine the electromagnetic force in railguns. The 3dimensional (3-D) finite clement code MEGA, developed at the University of Bath, was used to simulate the transient electromagnetic field in conventional, transaugmented and muzzle fed railgun configurations. These time-dependent simulations used a step input of current together with armature velocities

  1. Historical electromagnetic propagation condition database description

    Microsoft Academic Search

    W. L. Patterson

    1987-01-01

    Described is an electromagnetic propagation conditions climatological database, a subset of which is employed by the Historical Electromagnetic Propagation Conditions Summary Function (HEPC) within the Tactical Environmental Support System (TESS). The HEPC function generates a climatological description of the refractive conditions for user-specified geographic location. The climatological description is composed of five parts: a percent occurrence of enhanced surface-to-surface radar

  2. Generating highly uniform electromagnetic field characteristics

    DOEpatents

    Crow, James T. (Albuquerque, NM)

    1998-01-01

    An apparatus and method for generating homogenous electromagnetic fields within a volume. The homogeneity provided may be for magnetic and/or electric fields, and for field magnitude, radial gradient, or higher order radial derivative. The invention comprises conductive pathways oriented about a desired region of homogeneity. A corresponding apparatus and method is provided for substantially canceling the electromagnetic field outside of the apparatus, comprising a second set of conductive pathways placed outside the first set.

  3. Apparatus and Methods for Mitigating Electromagnetic Emissions

    NASA Technical Reports Server (NTRS)

    Geng, Steven M. (Inventor); Niedra, Janis M. (Inventor)

    2013-01-01

    Apparatus, methods, and other embodiments associated with mitigation of magnetic fields are described herein. In an embodiment, a method for mitigating an electromagnetic field includes positioning a mitigating coil around a linear alternator of linear motor so that the mitigating coil is coaxially located with an alternator coil; arranging the mitigating coil to generate a field to mitigate an electromagnetic field generated by the alternator coil; and passing an induced current from the alternator coil through the mitigating coil.

  4. Generating highly uniform electromagnetic field characteristics

    DOEpatents

    Crow, James Terry (Albuquerque, NM)

    1998-01-01

    An apparatus and method for generating homogenous electromagnetic fields within a volume. The homogeneity provided may be for magnetic and/or electric fields, and for field magnitude, radial gradient, or higher order radial derivative. The invention comprises conductive pathways oriented mirror symmetrically about a desired region of homogeneity. A corresponding apparatus and method is provided for substantially canceling the electromagnetic field outside of the apparatus, comprising a second set of conductive pathways placed outside the first set.

  5. Generating highly uniform electromagnetic field characteristics

    DOEpatents

    Crow, James T. (Albuquerque, NM)

    1997-01-01

    An apparatus and method for generating homogenous electromagnetic fields within a volume. The homogeneity provided may be for magnetic and/or electric fields, and for field magnitude, radial gradient, or higher order radial derivative. The invention comprises conductive pathways oriented mirror symmetrically about a desired region of homogeneity. A corresponding apparatus and method is provided for substantially cancelling the electromagnetic field outside of the apparatus, comprising a second set of conductive pathways placed outside the first set.

  6. Electromagnetic Corrections in Staggered Chiral Perturbation Theory

    E-print Network

    C. Bernard; E. D. Freeland

    2010-11-17

    To reduce errors in light-quark mass determinations, it is now necessary to consider electromagnetic contributions to light-meson masses. Calculations using staggered quarks and quenched photons are currently underway. Suitably-extended chiral perturbation theory is necessary to extrapolate the lattice data to the physical limit. Here we give (preliminary) results for light-meson masses using staggered chiral perturbation theory including electromagnetism, and discuss the extent to which quenched-photon simulations can improve quark-mass calculations.

  7. Electromagnetic and spin polarisabilities in lattice QCD

    E-print Network

    W. Detmold; B. C. Tiburzi; A. Walker-Loud

    2006-10-02

    We discuss the extraction of the electromagnetic and spin polarisabilities of nucleons from lattice QCD. We show that the external field method can be used to measure all the electromagnetic and spin polarisabilities including those of charged particles. We then turn to the extrapolations required to connect such calculations to experiment in the context of chiral perturbation theory, finding a strong dependence on the lattice volume and quark masses.

  8. Stochastic electromagnetic radiation of complex sources.

    PubMed

    Naus, H W L

    2007-08-01

    The emission of electromagnetic radiation by localized complex electric charge and current distributions is studied. A statistical formalism in terms of general dynamical multipole fields is developed. The appearing coefficients are treated as stochastic variables. Hereby as much as possible a priori physical knowledge is exploited. First results of simulated statistical electromagnetic fields as a function of position are presented. Sampling this field at one point approximates its resulting probability density. PMID:17930162

  9. High-Power Electromagnetic Thruster Being Developed

    NASA Technical Reports Server (NTRS)

    LaPointe, Michael R.; Mikellides, Pavlos G.

    2001-01-01

    High-power electromagnetic thrusters have been proposed as primary in-space propulsion options for several bold new interplanetary and deep-space missions. As the lead center for electric propulsion, the NASA Glenn Research Center designs, develops, and tests high-power electromagnetic technologies to meet these demanding mission requirements. Two high-power thruster concepts currently under investigation by Glenn are the magnetoplasmadynamic (MPD) thruster and the Pulsed Inductive Thruster (PIT).

  10. Numerical Electromagnetic Field Analysis for EMC Problems

    Microsoft Academic Search

    Heinz-Dietrich Bruns; Christian Schuster; Hermann Singer

    2007-01-01

    Much progress has been made in the use of computational electromagnetics for the analysis of electromagnetic compatibility (EMC) problems during recent years. This paper reviews the improvements in some of the most important techniques of the field: the method of moments, the finite-difference time-domain method, the finite-element method, the transmission-line matrix method, and the partial-element equivalent-circuit method. The results of

  11. Electromagnetic Heating Methods for Heavy Oil Reservoirs

    SciTech Connect

    Sahni, A.; Kumar, M.; Knapp, R.B.

    2000-05-01

    The most widely used method of thermal oil recovery is by injecting steam into the reservoir. A well-designed steam injection project is very efficient in recovering oil, however its applicability is limited in many situations. Simulation studies and field experience has shown that for low injectivity reservoirs, small thickness of the oil-bearing zone, and reservoir heterogeneity limits the performance of steam injection. This paper discusses alternative methods of transferring heat to heavy oil reservoirs, based on electromagnetic energy. They present a detailed analysis of low frequency electric resistive (ohmic) heating and higher frequency electromagnetic heating (radio and microwave frequency). They show the applicability of electromagnetic heating in two example reservoirs. The first reservoir model has thin sand zones separated by impermeable shale layers, and very viscous oil. They model preheating the reservoir with low frequency current using two horizontal electrodes, before injecting steam. The second reservoir model has very low permeability and moderately viscous oil. In this case they use a high frequency microwave antenna located near the producing well as the heat source. Simulation results presented in this paper show that in some cases, electromagnetic heating may be a good alternative to steam injection or maybe used in combination with steam to improve heavy oil production. They identify the parameters which are critical in electromagnetic heating. They also discuss past field applications of electromagnetic heating including technical challenges and limitations.

  12. Elec Eng 2FH3 Electromagnetics I COURSE NUMBER & TITLE: Elec Eng 2FH3 Electromagnetics I

    E-print Network

    Haykin, Simon

    Elec Eng 2FH3 ­ Electromagnetics I COURSE NUMBER & TITLE: Elec Eng 2FH3 ­ Electromagnetics I field 6. Inductance 7. Faraday's law CALENDAR DESCRIPTION: Electromagnetics Part I is an introduction into engineering electromagnetics. It covers the mathematical foundations such as selected topics of vector

  13. ALICE electromagnetic calorimeter prototype test

    SciTech Connect

    Awes, Terry; /Oak Ridge

    2005-09-01

    This Memorandum of Understanding between the Test Beam collaborators and Fermilab is for the use of beam time at Fermilab during the Fall, 2005 Meson Test Beam Run. The experimenters plan to measure the energy, position, and time resolution of prototype modules of a large electromagnetic calorimeter proposed to be installed in the ALICE experiment at the LHC. The ALICE experiment is one of the three large approved LHC experiments, with ALICE placing special emphasis on the LHC heavy-ion program. The large electromagnetic calorimeter (EMCal) is a US initiative that is endorsed by the ALICE collaboration and is currently in the early stages of review by the Nuclear Physics Division of the DOE. The installation in the test beam at FNAL and test beam measurements will be carried out by the US members of the ALICE collaboration (ALICE-USA). The overall design of the ALICE EMCal is heavily influenced by its location within the ALICE L3 magnet. The EMCal is to be located inside the large room temperature magnet within a cylindrical integration volume approximately l12cm deep, by 5.6m in length, sandwiched between the ALICE TPC space frame and the L3 magnet coils. The chosen technology is a layered Pb-scintillator sampling calorimeter with a longitudinal pitch of 1.6mm Pb and 1.6mm scintillator. The full detector spans {eta} = -0.7 to {eta} = 0.7 with an azimuthal acceptance of {Delta}{phi} = 120{sup o}. The EMCal readout is of a ''Shish-Kabob'' type similar to the PHENIX Pb-scintillator sampling calorimeter in which the scintillation light is collected via wavelength shifting fibers running through the Pb-scintillator tiles perpendicular to the front surface. The detector is segmented into {approx}14000 towers. The basic structural units of the calorimeter are supermodules, each subtending approximately {approx}20{sup o} in {Delta}{phi} and 0.7 units in {Delta}{eta}. Supermodules are assembled from individual modules. The modules are further segmented into 2 x 2 individually read out towers. The fibers from an individual tower are grouped together to form readout tower bundles. These are each optically coupled to an avalanche photodiode (APO) via a short light guide to provide some spatial optical mixing and to match the fiber bundle to the APO. The module assembly is indicated in Figure l. The supermodules weigh about 9.6 tons and are the basic units handled during installation. Each supermodule is roughly I45cm wide at the front surface by 350cm long with an active depth of 24.5cm (at {eta} = 0) plus an additional 6.6 cm of depth in structural plates. The physical characteristics of the ALICE EMCal are summarized in Table 1. The EMCal test beam measurements at FNAL will utilize a stacked 4 x 4 array of prototype EMCal modules (8 x 8 towers). All towers will be instrumented with the same model APO and preamplifier as will be used in the ALICE experiment and all channels will be readout with existing prototype front end electronics intended for use in ALICE. The goals of the test beam measurements are: To investigate the energy resolution, linearity, uniformity, and position resolution, using electron beams; To study the energy dependence of the response to electrons and hadrons to determine the particle identification capabilities of the EMCal by shower shape; And to investigate the timing characteristics of the energy signal for crude time-of-flight measurement ({approx} 1ns) for use for anti-neutron rejection. Measurements will be made for comparison with different signal shaping times in the front end electronics.

  14. Is Electromagnetic Gravity Control Possible?

    SciTech Connect

    Vargas, Jose G. [PST Associates, 600 Westover Rd, Columbia, SC 29210 (United States); Torr, Douglas G. [PST Associates, 5221 Tern Place, Fayetteville, NC 28311-1967 (United States)

    2004-02-04

    We study the interplay of Einstein's Gravitation (GR) and Maxwell's Electromagnetism, where the distribution of energy-momentum is not presently known (The Feynman Lectures, Vol 2, Chapter 27, section 4). As Feynman himself stated, one might in principle use Einstein's equations of GR to find such a distribution. GR (born in 1915) presently uses the Levi-Civita connection, LCC (the LCC was born two years after GR as a new concept, and not just as the pre-existing Christoffel symbols that represent it). Around 1927, Einstein proposed for physics an alternative to the LCC that constitutes a far more sensible and powerful affine enrichment of metric Riemannian geometry. It is called teleparallelism (TP). Its Finslerian version (i.e. in the space-time-velocity arena) permits an unequivocal identification of the EM field as a geometric quantity. This in turn permits one to identify a completely geometric set of Einstein equations from curvature equations. From their right hand side, one may obtain the actual distribution of EM energy-momentum. It is consistent with Maxwell's equations, since these also are implied by the equations of structure of TP. We find that the so-far-unknown terms in this distribution amount to a total differential and do not, therefore, alter the value of the total EM energy-momentum. And yet these extra terms are at macroscopic distances enormously larger than the standard quadratic terms. This allows for the generation of measurable gravitational fields by EM fields. We thus answer affirmatively the question of the title.

  15. Nonlinear electromagnetic and gravitational actions of neutron star fields on electromagnetic wave propagation

    Microsoft Academic Search

    Victor I. Denisov; Sergei I. Svertilov

    2005-01-01

    The nonlinear electrodynamic and gravitational actions on the weak electromagnetic wave propagation in the strong dipole magnetic and gravitational fields of a neutron star are discussed. The eikonal equations for an electromagnetic wave propagating in the external field as well as the motion equations of photons in the dipole magnetic and gravitational fields of a neutron star are obtained from

  16. Nonholonomic catheter path reconstruction using electromagnetic tracking

    NASA Astrophysics Data System (ADS)

    Lugez, Elodie; Sadjadi, Hossein; Akl, Selim G.; Fichtinger, Gabor

    2015-03-01

    Catheter path reconstruction is a necessary step in many clinical procedures, such as cardiovascular interventions and high-dose-rate brachytherapy. To overcome limitations of standard imaging modalities, electromagnetic tracking has been employed to reconstruct catheter paths. However, tracking errors pose a challenge in accurate path reconstructions. We address this challenge by means of a filtering technique incorporating the electromagnetic measurements with the nonholonomic motion constraints of the sensor inside a catheter. The nonholonomic motion model of the sensor within the catheter and the electromagnetic measurement data were integrated using an extended Kalman filter. The performance of our proposed approach was experimentally evaluated using the Ascension's 3D Guidance trakStar electromagnetic tracker. Sensor measurements were recorded during insertions of an electromagnetic sensor (model 55) along ten predefined ground truth paths. Our method was implemented in MATLAB and applied to the measurement data. Our reconstruction results were compared to raw measurements as well as filtered measurements provided by the manufacturer. The mean of the root-mean-square (RMS) errors along the ten paths was 3.7 mm for the raw measurements, and 3.3 mm with manufacturer's filters. Our approach effectively reduced the mean RMS error to 2.7 mm. Compared to other filtering methods, our approach successfully improved the path reconstruction accuracy by exploiting the sensor's nonholonomic motion constraints in its formulation. Our approach seems promising for a variety of clinical procedures involving reconstruction of a catheter path.

  17. Power law inflation with electromagnetism

    SciTech Connect

    Luo, Xianghui; Isenberg, James, E-mail: isenberg@uoregon.edu

    2013-07-15

    We generalize Ringström’s global future causal stability results (Ringström 2009) [11] for certain expanding cosmological solutions of the Einstein-scalar field equations to solutions of the Einstein–Maxwell-scalar field system. In particular, after noting that the power law inflationary spacetimes (M{sup n+1},g{sup -hat}, ?{sup -hat}) considered by Ringström (2009) in [11] are solutions of the Einstein–Maxwell-scalar field system (with exponential potential) as well as of the Einstein-scalar field system (with the same exponential potential), we consider (nonlinear) perturbations of initial data sets of these spacetimes which include electromagnetic perturbations as well as gravitational and scalar perturbations. We show that if (as in Ringström (2009) [11]) we focus on pairs of relatively scaled open sets U{sub R{sub 0}}?U{sub 4R{sub 0}} on an initial slice of (M{sup n+1},g{sup -hat}), and if we choose a set of perturbed data which on U{sub 4R{sub 0}} is sufficiently close to that of (M{sup n+1},g{sup -hat},?{sup -hat}, A{sup -hat} = 0), then in the maximal globally hyperbolic spacetime development (M{sup n+1},g,?,A) of this data via the Einstein–Maxwell-scalar field equations, all causal geodesics emanating from U{sub R{sub 0}} are future complete (just as in (M{sup n+1},g{sup -hat})). We also verify that, in a certain sense, the future asymptotic behavior of the fields in the spacetime developments of the perturbed data sets does not differ significantly from the future asymptotic behavior of (M{sup n+1},g{sup -hat}, ?{sup -hat}, A{sup -hat} = 0). -- Highlights: •We prove stability of expanding solutions of the Einstein–Maxwell-scalar field equations. •All nearby solutions are geodesically complete. •The topology of the initial slice is irrelevant to our stability results.

  18. Planar electromagnetic band-gap structure based on graphene

    NASA Astrophysics Data System (ADS)

    Dong, Yanfei; Liu, Peiguo; Yin, Wen-Yan; Li, Gaosheng; Yi, Bo

    2015-06-01

    Electromagnetic band-gap structure with slow-wave effect is instrumental in effectively controlling electromagnetic wave propagation. In this paper, we theoretically analyze equivalent circuit model of electromagnetic band-gap structure based on graphene and evaluate its potential applications. Graphene electromagnetic band-gap based on parallel planar waveguide is investigated, which display good characteristics in dynamically adjusting the electromagnetic wave propagation in terahertz range. The same characteristics are retrieved in a spiral shape electromagnetic band-gap based on coplanar waveguide due to tunable conductivity of graphene. Various potential terahertz planar devices are expected to derive from the prototype structures.

  19. Advanced electromagnetic methods for aerospace vehicles

    NASA Technical Reports Server (NTRS)

    Balanis, Constantine A.; Sun, Weimin; El-Sharawy, El-Budawy; Aberle, James T.; Birtcher, Craig R.; Peng, Jian; Tirkas, Panayiotis A.

    1992-01-01

    The Advanced Helicopter Electromagnetics (AHE) Industrial Associates Program continues its research on variety of main topics identified and recommended by the Advisory Task Force of the program. The research activities center on issues that advance technology related to helicopter electromagnetics. While most of the topics are a continuation of previous works, special effort has been focused on some of the areas due to recommendations from the last annual conference. The main topics addressed in this report are: composite materials, and antenna technology. The area of composite materials continues getting special attention in this period. The research has focused on: (1) measurements of the electrical properties of low-conductivity materials; (2) modeling of material discontinuity and their effects on the scattering patterns; (3) preliminary analysis on interaction of electromagnetic fields with multi-layered graphite fiberglass plates; and (4) finite difference time domain (FDTD) modeling of fields penetration through composite panels of a helicopter.

  20. Gallium Electromagnetic (GEM) Thrustor Concept and Design

    NASA Technical Reports Server (NTRS)

    Polzin, Kurt A.; Markusic, Thomas E.

    2006-01-01

    We describe the design of a new type of two-stage pulsed electromagnetic accelerator, the gallium electromagnetic (GEM) thruster. A schematic illustration of the GEM thruster concept is given in Fig. 1. In this concept, liquid gallium propellant is pumped into the first stage through a porous metal electrode using an electromagneticpump[l]. At a designated time, a pulsed discharge (approx.10-50 J) is initiated in the first stage, ablating the liquid gallium from the porous electrode surface and ejecting a dense thermal gallium plasma into the second state. The presence of the gallium plasma in the second stage serves to trigger the high-energy (approx.500 I), send-stage puke which provides the primary electromagnetic (j x B) acceleration.

  1. Electromagnetically induced absorption via incoherent collisions

    SciTech Connect

    Yang Xihua [Department of Physics, University of Arkansas, Fayetteville, Arkansas 72701 (United States); Department of Physics, Shanghai University, Shanghai 200444 (China); Sheng Jiteng; Xiao Min [Department of Physics, University of Arkansas, Fayetteville, Arkansas 72701 (United States)

    2011-10-15

    We conduct theoretical studies on electromagnetically induced absorption via incoherent collisions in an inhomogeneously broadened ladder-type three-level system with the density-matrix approach. The effects of the collision-induced coherence decay rates as well as the probe laser field intensity on the probe field absorption are examined. It is shown that with the increase of the collisional decay rates in a moderate range, a narrow dip due to electromagnetically induced transparency superimposed on the Doppler-broadened absorption background can be turned into a narrow peak under the conditions that the probe field intensity is not very weak as compared to the pump field, which results from the enhancement of constructive interference and suppression of destructive interference between one-photon and multiphoton transition pathways. The physical origin of the collision-assisted electromagnetically induced absorption is analyzed with a power-series solution of the density-matrix equations.

  2. Complex geometry and pre-metric electromagnetism

    E-print Network

    D. H. Delphenich

    2004-12-10

    The intimate link between complex geometry and the problem of the pre-metric formulation of electromagnetism is explored. In particular, the relationship between 3+1 decompositions of R4 and the decompositions of the vector space of bivectors over R4 into real and imaginary subspaces relative to a choice of complex structure is emphasized. The role of the various scalar products on the space of bivectors that are defined in terms of a volume element on R4 and a complex structure on the space of bivectors that makes it C-linear isomorphic to C3 is discussed in the context of formulation of a theory of electromagnetism in which the Lorentzian metric on spacetime follows as a consequence of the existence of electromagnetic waves, not a prior assumption.

  3. Electromagnetic Radiations as a Fluid Flow

    E-print Network

    Daniele Funaro

    2009-11-25

    We combine Maxwell's equations with Eulers's equation, related to a velocity field of an immaterial fluid, where the density of mass is replaced by a charge density. We come out with a differential system able to describe a relevant quantity of electromagnetic phenomena, ranging from classical dipole waves to solitary wave-packets with compact support. The clue is the construction of an energy tensor summing up both the electromagnetic stress and a suitable mass tensor. With this right-hand side, explicit solutions of the full Einstein's equation are computed for a wide class of wave phenomena. Since our electromagnetic waves may behave and interact exactly as a material fluid, they can create vortex structures. We then explicitly analyze some vortex ring configurations and examine the possibility to build a model for the electron.

  4. Electromagnetic energy momentum in dispersive media

    SciTech Connect

    Philbin, T. G. [School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews, Fife, KY16 9SS, Scotland (United Kingdom)

    2011-01-15

    The standard derivations of electromagnetic energy and momentum in media take Maxwell's equations as the starting point. It is well known that for dispersive media this approach does not directly yield exact expressions for the energy and momentum densities. Although Maxwell's equations fully describe electromagnetic fields, the general approach to conserved quantities in field theory is not based on the field equations, but rather on the action. Here an action principle for macroscopic electromagnetism in dispersive, lossless media is used to derive the exact conserved energy-momentum tensor. The time-averaged energy density reduces to Brillouin's simple formula when the fields are monochromatic. The time-averaged momentum density for monochromatic fields corresponds to the familiar Minkowski expression DxB, but for general fields in dispersive media the momentum density does not have the Minkowski value. The results are unaffected by the debate over momentum balance in light-matter interactions.

  5. Feedback controlled electrostatic and electromagnetic sample positioners

    NASA Technical Reports Server (NTRS)

    Rhim, Won-Kyu; Elleman, D. D.

    1990-01-01

    Four different sample positioners are discussed. The four systems share a common operating principle in that the sample positioning is achieved by feedback controlled forces which can be electrostatic, dielectrophoretic, or electromagnetic. The first system is the electrostatic liquid drop positioner which operates at the near ambient position. The second system is the tetrahedral electrostatic positioner which is being developed for the high temperature materials processing in vacuum. The third system is essentially the the same tetrahedral system above except that the position control is achieved by dielectrophoretic forces in the pressurized gas environment. Finally, the feasibility of a feedback controlled electromagnetic positioner is discussed.

  6. Electromagnetic continuous casting project: Final report

    SciTech Connect

    Battles, J.E.; Rote, D.M.; Misra, B.; Praeg, W.F.; Hull, J.R.; Turner, L.R.; Shah, V.L.; Lari, R.J.; Gopalsami, N.; Wiencek, T.

    1988-10-01

    This report describes the work on development of an electromagnetic casting process for steel, which was carried out at Argonne National Laboratory between January 1985 and December 1987. This effort was concerned principally with analysis and design work on magnet technology, liquid metal feed system, coolant system, and sensors and process controllers. Experimentation primarily involved (1) electromagnetic studies to determine the conditions and controlling parameters for stable levitation and (2) feed-system studies to establish important parameters that control and influence fluid flow from the liquid metal source to the caster. 73 refs., 91 figs., 11 tabs.

  7. Device and method for redirecting electromagnetic signals

    DOEpatents

    Garcia, Ernest J. (823 Piedra Larga, NE., Albuquerque, NM 87123)

    1999-01-01

    A device fabricated to redirect electromagnetic signals, the device including a primary driver adapted to provide a predetermined force, a linkage system coupled to the primary driver, a pusher rod rotationally coupled to the linkage system, a flexible rod element attached to the pusher rod and adapted to buckle upon the application of the predetermined force, and a mirror structure attached to the flexible rod element at one end and to the substrate at another end. When the predetermined force buckles the flexible rod element, the mirror structure and the flexible rod element both move to thereby allow a remotely-located electromagnetic signal directed towards the device to be redirected.

  8. Scanning evanescent electro-magnetic microscope

    DOEpatents

    Xiang, Xiao-Dong (Alameda, CA); Gao, Chen (Alameda, CA)

    2001-01-01

    A novel scanning microscope is described that uses near-field evanescent electromagnetic waves to probe sample properties. The novel microscope is capable of high resolution imaging and quantitative measurements of the electrical properties of the sample. The inventive scanning evanescent wave electromagnetic microscope (SEMM) can map dielectric constant, tangent loss, conductivity, complex electrical impedance, and other electrical parameters of materials. The quantitative map corresponds to the imaged detail. The novel microscope can be used to measure electrical properties of both dielectric and electrically conducting materials.

  9. The Electromagnetic Duality Formulation of Geometric Phases

    NASA Astrophysics Data System (ADS)

    Zhang, Yuchao; Li, Kang

    2015-06-01

    This paper focuses on the electromagnetic(EM) duality formulation of geometric phases of Aharonov-Bohm(A-B) effect and Aharonov-Casher(A-C) effect. Through the two four-vector potential formulation of electromagnetic theory, we construct a EM duality formulation for both A-B effect and A-C effect. The He-McKellar-Wilkens(HMW) effect is included as a EM duality counterpart of the A-C effect, and also the EM duality counterpart of the A-B effect is also predicted.

  10. Duality in Off-Shell Electromagnetism

    E-print Network

    Martin Land

    2006-03-21

    In this paper, we examine the Dirac monopole in the framework of Off-Shell Electromagnetism, the five dimensional U(1) gauge theory associated with Stueckelberg-Schrodinger relativistic quantum theory. After reviewing the Dirac model in four dimensions, we show that the structure of the five dimensional theory prevents a natural generalization of the Dirac monopole, since the theory is not symmetric under duality transformations. It is shown that the duality symmetry can be restored by generalizing the electromagnetic field strength to an element of a Clifford algebra. Nevertheless, the generalized framework does not permit us to recover the phenomenological (or conventional) absence of magnetic monopoles.

  11. Electromagnetic Observables in Few-Nucleon Systems

    E-print Network

    Sonia Bacca

    2012-10-10

    The electromagnetic probe is a very valuable tool to study the dynamics of few nucleons. It can be very helpful in shedding light on the not yet fully understood three-nucleon forces. We present an update on the theoretical studies of electromagnetic induced reactions, such as photo-disintegration and electron scattering off 4He. We will show that they potentially represent a tool to discriminate among three-nucleon forces. Then, we will discuss the charge radius and the nuclear electric polarizability of the 6He halo nucleus.

  12. Electromagnetic waves, gravitational coupling and duality analysis

    E-print Network

    E. M. C. Abreu; C. Pinheiro; S. A. Diniz; F. C. Khanna

    2005-10-27

    In this letter we introduce a particular solution for parallel electric and magnetic fields, in a gravitational background, which satisfy free-wave equations and the phenomenology suggested by astrophysical plasma physics. These free-wave equations are computed such that the electric field does not induce the magnetic field and vice-versa. In a gravitational field, we analyze the Maxwell equations and the corresponding electromagnetic waves. A continuity equation is presented. A commutative and noncommutative analysis of the electromagnetic duality is described.

  13. [Electromagnetic fields--effects on health].

    PubMed

    Stepansky, R; Jahn, O; Windischbauer, G; Zeitlhofer, J

    2000-01-01

    This literature review shows the current knowledge of health effects on humans concerning static, low frequency electric and magnetic fields and high frequency electromagnetic fields up to 300 GHz. Basic physical knowledge and the current thresholds are demonstrated. Different frequency ranges of electromagnetic fields, their natural and technical origins and the different biological effects, especially possible hazards such as cancerogenity or risks for the brain, are discussed. Open questions and future research aspects are demonstrated. Finally electrosensibility and psychological aspects are shown. PMID:10897385

  14. NASA GRC High Power Electromagnetic Thruster Program

    NASA Technical Reports Server (NTRS)

    LaPointe, Michael R.; Pensil, Eric J.

    2004-01-01

    High-power electromagnetic thrusters have been proposed as primary in-space propulsion options for several bold new interplanetary and deep-space missions. As the lead center for electric propulsion, the NASA Glenn Research Center designs, develops, and tests high-power electromagnetic technologies to meet these demanding mission requirements. Two high-power thruster concepts currently under investigation by Glenn are the magnetoplasmadynamic (MPD) thruster and the Pulsed Inductive Thruster (PIT). This paper describes the MPD thruster and the test facility.

  15. Electromagnetic vacuum fluctuations and electron coherence

    NASA Astrophysics Data System (ADS)

    Ford, L. H.

    1993-06-01

    The coupling of the quantized electromagnetic field to coherent electrons is investigated. The effects both of photon emission and of the electromagnetic vacuum fluctuations upon electron interference are analyzed. The modifications of the vacuum fluctuations due to a conducting plate lead to a decrease in the amplitude of the interference oscillations. The possibility of observing this effect is discussed. It is also shown that there is an analogue of the Aharonov-Bohm effect in which electron interference is sensitive to vacuum fluctutations in regions from which the electrons are excluded.

  16. [Electromagnetic Shielding Alters Behaviour of Rats].

    PubMed

    Temuryants, N A; Kostyuk, A S; Tumanyants, K N

    2015-01-01

    It has been found that long-term electromagnetic shielding (19 hours per day for 10 days) leads to an increase in the duration of passive swimming time in male rats, decrease the duration of active swimming in the "forced swim" test as well as decrease of libido. On the other hand animals kept under the "open field" conditions do not show significant deviations from their normal behavior. Therefore, one could conclude that moderate electromagnetic shielding causes a depression-like state in rats. PMID:26080600

  17. Subwavelength electromagnetic shielding by resonant surface

    NASA Astrophysics Data System (ADS)

    Wen, He; Hou, Bo; Wen, Weijia

    2006-11-01

    The authors studied the influence of a small resonant surface on the radiation pattern of a monopole wire antenna when the resonant surface was placed in proximity. By discussing both experiment and simulation results, the authors found that the small resonant surface can effectively block the electromagnetic wave with wavelength which is greater than its dimension. The underlying principle is attributed to the nature of resonance. Therefore, a small resonant surface may function as a subwavelength reflector and protect, to some degree, humans from exposure to electromagnetic radiation.

  18. Bioelectromagnetic effects of the electromagnetic pulse (EMP)

    SciTech Connect

    Patrick, E.L.; Vault, W.L.

    1990-03-01

    The public has expressed concern about the biological effects and hazards of non-ionizing electromagnetic fields produced by the electro-magnetic pulse (EMP) simulators that simulate the EMP emanating from a high-altitude nuclear explosion. This paper provides a summary of the bioelectromagnetic effects literature up through the present, describes current occupational standards for workers exposed to the EMP environment, and discusses the use of medical surveillance as it relates to the potential human health hazards associated with exposure to the EMP environment.

  19. The electromagnetic interaction in chiral perturbation theory

    NASA Astrophysics Data System (ADS)

    Neufeld, H.; Rupertsberger, H.

    1996-03-01

    We investigate electromagnetic effects in the framework of chiral perturbation theory. Using a completely independent method, we confirm Urech’s results for the divergences of the one-loop functional in the electromagnetic sector. We perform a one-loop analysis of all P t2 ( P=?, K, ?) and the K t3 form factorsf_ + ^{K^ + ? ^o } (0),f_ + ^{K^o ? ^ - } (0), including a systematic treatment of the O( e 2 p 2) contributions in the mesonic part. We illustrate our results by several numerical estimates.

  20. Biological effects of electromagnetic fields on vertebrates. A review

    Microsoft Academic Search

    Bo Algers; Katarina Hennichs

    1983-01-01

    Papers dealing with biological effects of electromagnetic fields are reviewed. The data indicate that certain biological changes are caused by exposure to electromagnetic fields. There is at present, however, no evidence of specific causal mechanisms.

  1. Micro-electromagnetic formation flight of satellite systems

    E-print Network

    Sakaguchi, Aya, S.M. Massachusetts Institute of Technology

    2007-01-01

    Electromagnetic formation flight (EMFF) investigates the concept of using electromagnets to provide the forces to maintain a satellite's relative position in a formation. Thus far, high temperature superconducting (HTS) ...

  2. Electromagnetic signature of human cortical dynamics during wakefulness and sleep

    E-print Network

    Paris-Sud XI, Université de

    Electromagnetic signature of human cortical dynamics during wakefulness and sleep Signature.1.1 Electroencephalography (EEG) . . . . . . . . . . . . . . . . . . . . . 21 1.1.2 Magnetoencephalography (MEG Studies 45 4 Overview 47 4.1 Electromagnetic properties of the extracellular medium

  3. Fractional Diffusion Modeling of Electromagnetic Induction in Fractured Rocks 

    E-print Network

    Ge, Jianchao

    2014-08-11

    The controlled-source electromagnetic (CSEM) technique is well-established for non-invasive geophysical survey. Due to the strong attenuation of earth materials to electromagnetic signals, the effective depth of most CSEM surveys is restricted to 1...

  4. On the gravitational fields created by the electromagnetic waves

    E-print Network

    A. Loinger; T. Marsico

    2011-06-11

    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.

  5. Scattering of Electromagnetic Waves by a Composite Cylinder

    Microsoft Academic Search

    Mohammed Azizul Islam

    1964-01-01

    The scattering of an obliquely incident electromagnetic wave by a composite cylinder has been obtained using fundamental electromagnetic principles. The general result has been reduced to simpler forms for certain special cases.

  6. Application of Electromagnetic Waves in Damage Detection of Concrete Structures

    E-print Network

    De Flaviis, Franco

    1 Application of Electromagnetic Waves in Damage Detection of Concrete Structures Maria Q. Fenga successfully detected. Keywords: Electromagnetic Wave, Imaging Technology, FRP Jacket, RC Column, Damage Detection 1. INTRODUCTION The enhanced structural performance of RC columns retrofitted by FPP composite

  7. Passive electromagnetic damping device for motion control of building structures

    E-print Network

    Palomera-Arias, Rogelio, 1972-

    2005-01-01

    The research presented in this thesis develops a new device for the passive control of motion in building structures: an electromagnetic damper. The electromagnetic damper is a self-excited device that provides a reaction ...

  8. 611: Electromagnetic Theory II Special relativity; Lorentz covariance of Maxwell equations

    E-print Network

    Pope, Christopher

    611: Electromagnetic Theory II CONTENTS · Special relativity; Lorentz covariance of Maxwell · Action principle for electromagnetism; energy-momentum tensor · Electromagnetic waves; waveguides Electromagnetic Fields 42 3.1 Description in terms of potentials

  9. 611: Electromagnetic Theory II Special relativity; Lorentz covariance of Maxwell equations

    E-print Network

    Pope, Christopher

    611: Electromagnetic Theory II CONTENTS #15; Special relativity; Lorentz covariance of Maxwell particles #15; Action principle for electromagnetism; energy-momentum tensor #15; Electromagnetic waves Electromagnetic Fields 38 3.1 Description in terms of potentials

  10. ARMY ELECTROMAGNETIC SPECTRUM DISTRIBUTION RESTRICTION. Approved for public release; distribution is unlimited.

    E-print Network

    US Army Corps of Engineers

    FM 6-02.70 ARMY ELECTROMAGNETIC SPECTRUM OPERATIONS May 2010 DISTRIBUTION RESTRICTION. Approved ELECTROMAGNETIC SPECTRUM OPERATIONS Contents Page PREFACE .............................................................................................................iii Chapter 1 ELECTROMAGNETIC SPECTRUM OPERATIONS INTRODUCTION............ 1-1 What is Electromagnetic

  11. 611: Electromagnetic Theory II . Special relativity; Lorentz covariance of Maxwell equations

    E-print Network

    Pope, Christopher

    611: Electromagnetic Theory II CONTENTS . Special relativity; Lorentz covariance of Maxwell . Action principle for electromagnetism; energy­momentum tensor . Electromagnetic waves; waveguides Electromagnetic Fields 42 3.1 Description in terms of potentials

  12. Electromagnetic scattering from short branching vegetation

    Microsoft Academic Search

    Tsenchieh Chiu; Kamal Sarabandi

    2000-01-01

    A polarimetric coherent electromagnetic scattering model for short branching vegetation is developed. With the realistic structures that reasonably describe the relative positions of the particles, this model is able to consider the coherent effect due to the phase difference between the scattered fields from different particles, and account for the second-order, near-field interaction between particles, to which the relative positions

  13. Radiation from electromagnetically driven Langmuir turbulence

    SciTech Connect

    Mjolhus, E.; Hanssen, A. [Univ. of Tromso (Norway)] [Univ. of Tromso (Norway); DuBois, D.F. [Los Alamos National Lab., NM (United States)] [Los Alamos National Lab., NM (United States)

    1995-09-01

    A two-level model for the interaction between the electromagnetic pump wave and the electrostatic turbulence is formulated for ionospheric radio modification experiments. On the local level, the Zakharov equations, or similar models, apply. The interaction with the global electromagnetic level is represented by a second-order current density averaged over the local spatial variable. The energy exchange between the local and global level is represented by a Joulean product involving this second-order current density. The global generation problem is solved in the simplest cases. The escaping energy flux in the sideband {omega} is shown to be represented as a folding between the power spectrum of the local source and a squared Airy function. This power spectrum has been calculated from numerical simulations of electromagnetically driven Langmuir turbulence, using a one-dimensional model of the Zakharov type, for varying values of the parameters. For parameters in the cascade range, narrow line structured spectra were obtained, while for parameters in the cavitation range, very broad featureless spectra were obtained. Comparison with recent experimental stimulated electromagnetic emissions data did not confirm a signature for the existence of cavitation in the experiments. 67 refs., 7 figs.

  14. Radiation from electromagnetically driven Langmuir turbulence

    NASA Astrophysics Data System (ADS)

    Mjųlhus, Einar; Hanssen, Alfred; DuBois, Donald F.

    1995-09-01

    A two-level model for the interaction between the electromagnetic pump wave and the electrostatic turbulence is formulated for ionospheric radio modification experiments. On the local level, the Zakharov equations, or similar models, apply. The interaction with the global electromagnetic level is represented by a second-order current density averaged over the local spatial variable. The energy exchange between the local and global level is represented by a Joulean product involving this second-order current density. The global generation problem is solved in the simplest cases. The escaping energy flux in the sideband ? is shown to be represented as a folding between the power spectrum of the local source and a squared Airy function. This power spectrum has been calculated from numerical simulations of electromagnetically driven Langmuir turbulence, using a one-dimensional model of the Zakharov type, for varying values of the parameters. For parameters in the cascade range, narrow line structured spectra were obtained, while for parameters in the cavitation range, very broad featureless spectra were obtained. Comparison with recent experimental stimulated electromagnetic emissions data did not confirm a signature for the existence of cavitation in the experiments.

  15. Weapon system survivability in electromagnetic environments

    Microsoft Academic Search

    W. R. Free; D. E. Clark

    1979-01-01

    The combination of today's weapon system sophistication and the requirements for them to operate in an increasingly dense electromagnetic environment has caused the weapon system survivability scope to be broadened. There is no lack of technology to assure survivability, but implementation of existing technology is not always applied properly in the managerial function. Managerial guidance and methodologies are being developed

  16. Distribution of electromagnetic force in permanent magnets

    Microsoft Academic Search

    L. H. de Medeiros; G. Reyne; G. Meunier; J. P. Yonnet

    1998-01-01

    Two dual formulations are proposed for the calculation of the electromagnetic forces in permanent magnets. The formulations are based on the virtual work principle with the use of nodal elements. Both methods allow the calculation of global force as well as local force densities. These densities depend on the expression of the magnetic energy or co-energy of the magnet. The

  17. Trends in brain applications of electromagnetic fields

    Microsoft Academic Search

    Mikael Persson; Andreas Fhager; Hana Trefna

    This paper gives an overview of new trends in the use of electromagnetic fields for medical applications for diagnostics and treatment focusing on brain applications. The trends are exemplified with applications from brain monitoring, source localization, stimulation microwave tomography and hyperthermia

  18. Electromagnetic Wave Propagation Through Chaff Clouds

    Microsoft Academic Search

    Sherman W. Marcus

    2007-01-01

    The computation of electromagnetic wave scattering by clouds of dipoles is straightforward when the dipole density is small. For higher density clouds, the coupling effects between the dipoles and their attenuation effects on the wave must be considered. This is accomplished herein by replacing the randomly distributed dipoles in the cloud by a conducting continuum. The conductivity of this continuum

  19. Learning Electromagnetism with Visualizations and Active Learning

    Microsoft Academic Search

    YEHUDIT JUDY DORI; John Belcher

    This chapter describes learning electromagnetism with visualizations and focuses on the value of concrete and visual representations in teaching abstract concepts. We start with a theoretical background consisting of three subsections: visualization in science, simulations and microcomputerbased laboratory, and studies that investigated the effectiveness of simulations and real-time graphing in physics. We then present the TEAL (Technology Enabled Active Learning)

  20. Nonlinear interaction between three ordinary electromagnetic modes

    Microsoft Academic Search

    P. Munoz; S. Dagach

    1977-01-01

    This paper considers the resonant interaction among three modified ordinary electromagnetic waves which propagate perpendicular to a constant magnetic field. It is shown that for the modified mode to be a normal mode, the unperturbed current must be equal to zero. The averaged Lagrangian method is used to calculate the coupling coefficient for the resonant interaction among three of these

  1. Analysis and simulation of electromagnetic transients in

    E-print Network

    Silva, Filipe Faria Da

    the research leading to this thesis "Analysis and simulation of electro- magnetic transients in HVAC cable and one PhD/industrial course on the field of electro- magnetic transients. The research resulted alsoAnalysis and simulation of electromagnetic transients in HVAC cable transmission grids Filipe

  2. Induction Machine Modelling for Electromagnetic Transient Program

    Microsoft Academic Search

    G. J. Rogers; D. Shirmohammadi

    1987-01-01

    A method is presented by which an accurate dynamic induction motor model may be developed from a knowledge of standard specification data for the motor. The incorporation of the model into the Electromagnetic Transients Program (EMTP) is described. Examples are given of its use in the study of the starting performance of a large induction motor and of the response

  3. Power quality analysis using electromagnetic transients programs

    Microsoft Academic Search

    Juan A. Martinez

    1998-01-01

    Power quality is a subject of great concern for electric utilities and their customers, since disturbances can have a very adverse effect on customer equipment. Several techniques have been developed over the last decades to simulate and analyze power quality problems using a digital computer. The EMTP (ElectroMagnetic Transients Program) and like are among the most popular tools based on

  4. Injection of transient faults using electromagnetic pulses

    E-print Network

    Injection of transient faults using electromagnetic pulses Practical results on a cryptographic of magnetic pulses to inject transient faults into the calculations of a RISC micro-controller running the AES to setup time violations resulting in the injection of errors. Transient deviations under nom- inal values

  5. Pullback transformation in gyrokinetic electromagnetic simulations

    SciTech Connect

    Mishchenko, Alexey, E-mail: alexey.mishchenko@ipp.mpg.de; Könies, Axel; Kleiber, Ralf; Cole, Michael [Max Planck Institute for Plasma Physics, D-17491 Greifswald (Germany)

    2014-09-15

    It is shown that a considerable mitigation of the cancellation problem can be achieved by a slight modification of the simulation scheme. The new scheme is verified, simulating a Toroidal Alfvén Eigenmode in tokamak geometry at low perpendicular mode numbers, the so-called “MHD limit.” Also, an electromagnetic drift mode has been successfully simulated in a stellarator.

  6. New variables for gyrokinetic electromagnetic simulations

    SciTech Connect

    Mishchenko, Alexey, E-mail: alexey.mishchenko@ipp.mpg.de; Cole, Michael; Kleiber, Ralf; Könies, Axel [Max Planck Institute for Plasma Physics, D-17491 Greifswald (Germany)

    2014-05-15

    A new approach to electromagnetic gyrokinetic simulations based on modified gyrokinetic theory is described. The method is validated using a particle-in-cell code. The Toroidal Alfvén Eigenmode at low perpendicular mode numbers, the so-called “magnetohydrodynamical limit,” has been successfully simulated using this method.

  7. The Electromagnetic Spectrum: Wavelength and Energy

    NSDL National Science Digital Library

    In this activity, students demonstrate the relationship between wave frequency and energy in the electromagnetic spectrum by shaking a rope to identify the relationships. This activity is part of Unit 2 in the Space Based Astronomy guide that contains background information, worksheets, assessments, extensions, and standards.

  8. Electromagnetic Force on a Moving Dipole

    ERIC Educational Resources Information Center

    Kholmetskii, Alexander L.; Missevitch, Oleg V.; Yarman, T.

    2011-01-01

    We analyse the force acting on a moving dipole due to an external electromagnetic field and show that the expression derived in Vekstein (1997 "Eur. J. Phys." 18 113) is erroneous and suggest the correct equation for the description of this force. We also discuss the physical meaning of the relativistic transformation of current for a closed…

  9. Generalized Electromagnetic fields in Chiral Medium

    E-print Network

    P. S. Bisht; Jivan Singh; O. P. S. Negi

    2007-03-12

    The time dependent Dirac-Maxwell's Equations in presence of electric and magnetic sources are written in chiral media and the solutions for the classical problem are obtained in unique simple and consistent manner. The quaternion reformulation of generalized electromagnetic fields in chiral media has also been developed in compact, simple and consistent manner.

  10. Electromagnetic optimization exploiting aggressive space mapping

    Microsoft Academic Search

    John W. Bandler; R. M. Biernacki; Shao Hua Chen; Ronald H. Hemmers; Kaj Madsen

    1995-01-01

    We propose a significantly improved space mapping (SM) strategy for electromagnetic (EM) optimization. Instead of waiting for upfront EM analyses at several base points, our new approach aggressively exploits every available EM analysis, producing dramatic results right from the first step. We establish a relationship between the novel SM optimization and the quasi-Newton iteration for solving a system of nonlinear

  11. Electromagnetism Adapted for Life Science Students

    ERIC Educational Resources Information Center

    Gurr, F. M.; And Others

    1974-01-01

    Describes the study of electronics as a terminal course in electromagnetism. A lecture-laboratory approach is used with a strong emphasis on practical experience. Outlines the major topics of the lecture program and describes the activities used in the laboratory. (GS)

  12. Relations Among Systems of Electromagnetic Equations

    ERIC Educational Resources Information Center

    page, Chester H.

    1970-01-01

    Contends that the equations of electromagnetism, whether in rationalized or non-rationalized form, express an invariant set of physical relationships. The relationships among corresponding symbols are given and applied to precise statements about the relation between the oersted and the amphere per meter, the abampere and the ampere, etc.…

  13. Charging Ahead: An Introduction to Electromagnetism.

    ERIC Educational Resources Information Center

    Shafer, Larry E.

    This guide explores the connection between electricity and magnetism with middle level and high school students. The phenomenon of electromagnetism is broken down into four lesson plans that provide students and teachers with a carefully constructed yet easy way to learn about their history. All four activities prompt students to use inexpensive,…

  14. The behavior of electromagnetic fields at edges

    Microsoft Academic Search

    J. Meixner

    1972-01-01

    The behavior of an electromagnetic field in the neighborhood of the common edge of angular dielectric or conducting regions is determined from the condition that the energy density must be integrable over any finite domain (the so-called edge condition). Two cases are treated in detail 1) A region consisting of a conducting wedge and two different dielectric wedges with a

  15. Electromagnetic Siegert states for periodic dielectric structures

    E-print Network

    Friends R. Ndangali; Sergei V. Shabanov

    2011-08-09

    The formalism of Siegert states to describe the resonant scattering in quantum theory is extended to the resonant scattering of electromagnetic waves on periodic dielectric arrays. The excitation of electromagnetic Siegert states by an incident wave packet and their decay is studied. The formalism is applied to develop a theory of coupled electromagnetic resonances arising in the electromagnetic scattering problem for two such arrays separated by a distance 2h (or, generally, when the physical properties of the scattering array depend on a real coupling parameter h). Analytic properties of Siegert states as functions of the coupling parameter h are established by the Regular Perturbation Theorem which is an extension the Kato-Rellich theorem to the present case. By means of this theorem, it is proved that if the scattering structure admits a bound state in the radiation continuum at a certain value of the coupling parameter h, then there always exist regions within the structure in which the near field can be amplified as much as desired by adjusting the value of h. This establishes a rather general mechanism to control and amplify optical nonlinear effects in periodically structured planar structures possessing a nonlinear dielectric susceptibility.

  16. Line geometry and electromagnetism I: basic structures

    E-print Network

    D. H. Delphenich

    2013-09-11

    Some key notions of line geometry are recalled, along with their application to mechanics. It is then shown that most of the basic structures that one introduces in the pre-metric formulation of electromagnetism can be interpreted directly in terms of corresponding concepts in line geometry. The results are summarized in a table.

  17. Microcirculatory effects of pulsed electromagnetic fields

    Microsoft Academic Search

    Thomas L. Smith; Donna Wong-Gibbons; Jane Maultsby

    2004-01-01

    Purpose: Pulsed electromagnetic fields (PEMF) are used clinically to expedite healing of fracture non-unions, however, the mechanism of action by which PEMF stimulation is effective is unknown. The current study examined the acute effects of PEMF stimulation on arteriolar microvessel diameters in the rat cremaster muscle. The study hypothesis was that PEMF would increase arteriolar diameters, a potential mechanism involved

  18. Evaluation of dynamic electromagnetic tracking deviation

    Microsoft Academic Search

    Johann Hummel; Michael Figl; Michael Bax; Ramin Shahidi; Helmar Bergmann; Wolfgang Birkfellner

    2009-01-01

    Electromagnetic tracking systems (EMTS's) are widely used in clinical applications. Many reports have evaluated their static behavior and errors caused by metallic objects were examined. Although there exist some publications concerning the dynamic behavior of EMTS's the measurement protocols are either difficult to reproduce with respect of the movement path or only accomplished at high technical effort. Because dynamic behavior

  19. Electromagnetic Fields and Possible Health Effects

    Microsoft Academic Search

    Chiyoji OHKUBO

    ????????????????????.????????????????????????.???,??? ??????,?????????????????????????.?????????????,??????? ?????????????????,????????????????????????????????????. ??????????????,????????????,???????????????.???,?????? ????????????????????????????????????????????????,????? ????????????.????????????????????????????,???????????? ??????????????????.?????????????????0.3-0.4µT ?????,???????? ??????????? µT ????????????,?????????????????????.??,??? ????????????????,13???????????????????????????????????? ?????????.WHO ?14????????????????????????????.?????????? ???????????????0-300GHz ?,??????.?????????,??????????????? ??????.????,WHO ??????????????????????????????????. Abstract Recent years have seen an unprecedented increase in the number and diversity of sources of electromagnetic fields (EMF) used for individual, industrial and commercial purposes. All these technologies have made our life richer and easier. All populations are now exposed to

  20. APPROXIMATION OF ELECTROMAGNETIC FIELDS: PART I ...

    E-print Network

    2003-08-06

    Electromagnetic energy estimates are obtained for our system. In section 4 ... frequency. An integral representation of the solutions will be presented. ... argument, which absorb uniformly traveling waves arriving at the boundary in given .... Moreover, let ? be a C1 continuous, symmetric positive-definite 3 × 3 matrix defined.

  1. Transient electromagnetic wave propagation in waveguides

    Microsoft Academic Search

    Gerhard Kristensson

    1995-01-01

    This paper focuses on propagation of transient electromagnetic waves in waveguides of general cross section with perfectly conducting walls. The solution of the transient wave propagation problem relies on a wave splitting technique, which has been frequently used in direct and inverse scattering problems during the last decade. The field in the waveguide is represented as a time convolution of

  2. Electromagnetic Waves in an Introductory Physics Course

    Microsoft Academic Search

    H. Y. Carr; R. L. Sells

    1960-01-01

    The properties of plane electromagnetic waves are derived without the use of calculus in a manner which provides a fundamental understanding of isolated waves far removed from their sources or any guiding conductors. The symmetrical relationship of the induced electric field to the induced magnetic field and the role of the displacement current are clearly demonstrated. Expressions for the velocity

  3. Electromagnetic Mass--Separation and Its Applications

    SciTech Connect

    Maoczka, D. [Institute for Atomic Energy, Swierk-Warsaw (Poland); Joint Institute for Nuclear Research, Dubna (Russian Federation); Turek, M.; Latuszynski, A. [Institute of Physics, Maria Curie-Sklodowska University, Lublin (Poland); Yushkevich, Yu. V. [Joint Institute for Nuclear Research, Dubna (Russian Federation)

    2009-03-31

    The article describes the electromagnetic mass-separation method and its application in nuclear and solid state physics. The limited review of the results in these fields, obtained by scientific groups at the Physics Institute, Maria Curie Sklodowska University, Lublin, Poland and the Joint Institute for Nuclear Research, Dubna, Russia is presented.

  4. Relativistic particle motion in nonuniform electromagnetic waves

    NASA Technical Reports Server (NTRS)

    Schmidt, G.; Wilcox, T.

    1973-01-01

    It is shown that a charged particle moving in a strong nonuniform electromagnetic wave suffers a net acceleration in the direction of the negative intensity gradient of the wave. Electrons will be expelled perpendicularly from narrow laser beams and various instabilities can result.

  5. Electromagnetic Wave Interactions with a Metamaterial Cloak

    Microsoft Academic Search

    Hongsheng Chen; Bae-Ian Wu; Baile Zhang; Jin Au Kong

    2007-01-01

    We establish analytically the interactions of electromagnetic wave with a general class of spherical cloaks based on a full wave Mie scattering model. We show that for an ideal cloak the total scattering cross section is absolutely zero, but for a cloak with a specific type of loss, only the backscattering is exactly zero, which indicates the cloak can still

  6. Optimization of an Electromagnetic Energy Harvesting Device

    Microsoft Academic Search

    Chitta Ranjan Saha; Terence O'Donnell; Heiko Loder; Steve Beeby; John Tudor

    2006-01-01

    This paper presents the modeling and optimization of an electromagnetic-based generator for generating power from ambient vibrations. Basic equations describing such generators are presented and the conditions for maximum power generation are described. Two-centimeter scale prototype generators, which consist of magnets suspended on a beam vibrating relative to a coil, have been built and tested. The measured power and modeled

  7. Electromagnetic fields in bone repair and adaptation

    NASA Astrophysics Data System (ADS)

    McLeod, Kenneth J.; Rubin, Clinton T.; Donahue, Henry J.

    1995-01-01

    The treatment of delayed union of bone fractures has served for the past 20 years as the principal testing ground for determining whether nonionizing electromagnetic fields can have any substantial, long-term effects in clinical medicine. Recent double-blinded clinical trials have confirmed the significance of the reported effects on bone healing and have led to the suggestion that electromagnetic fields may also be useful in the treatment of other orthopedic problems such as fresh fractures, stabilization of prosthetic implants, or even the prevention or treatment of osteoporosis. However, the design of appropriate treatment regimens for these new applications would be greatly facilitated if it were understood how the biological cells within bone tissue sense these low-frequency, and remarkably low level, electromagnetic fields. Here we address the engineering and physical science aspects of this problem. We review the characteristics of clinically used electromagnetic fields and discuss which components of these fields may actually be responsible for altering the activity of the bone cells. We then consider several physical mechanisms which have been proposed to explain how the cells within the bone or fracture tissue detect this field component.

  8. Propagation of electromagnetic pulses in terrestrial waveguides

    Microsoft Academic Search

    J. Wait

    1965-01-01

    The propagation of electromagnetic waves over the earth's surface is considered under transient conditions. The source is taken to be a vertical electric dipole whose current moment is suddenly established. The build-up of the radiated field is calculated under various assumed corditions. It is shown, even in the absence of an ionospherically reflected wave, that the influence of earth curvature

  9. Fractal surfaces and electromagnetic extended boundary conditions

    Microsoft Academic Search

    Giorgio Franceschetti; Antonio Iodice; Daniele Riccio; Giuseppe Ruello

    2002-01-01

    In this paper, we employ the extended boundary condition method with the Weierstrass-Mandelbrot (WM) fractal function to model and solve a relevant electromagnetic scattering problem. The key point of the procedure is the property of the WM to be an almost periodic function. This allows to generalize techniques employed for periodic problems and to express the field by means of

  10. Special relativity in the electromagnetic wave

    E-print Network

    Bernhard Rothenstein; Ioan Damian

    2005-04-27

    Invariance of the counted number of photons and the Lorentz-Einstein transformations enable us to derive transformation equations for the physical quantities introduced in order to characterize energy emission and transport in a plane and in a spherical electromagnetic wave propagating in vacuum.

  11. Electromagnetic remote sensing of sea ice

    Microsoft Academic Search

    A. K. Jordan; M. E. Veysoglu

    1994-01-01

    Electromagnetic remote sensing of sea ice is viewed to introduce relevant practical problems to the inverse scattering community. A brief introduction to the importance of sea ice and sea ice physics is followed by a summary of direct scattering models where extensive references are given. Typical inverse problems and models that use these direct scattering models are discussed to provide

  12. Quantized electromagnetic tornado in pulsar vacuum gap

    E-print Network

    Kontorovich, V M

    2009-01-01

    The solution for the electromagnetic tornado in a vacuum gap of a pulsar that could serve as an explanation of the observed circular polarization of giant pulses from pulsars and might also explain the frequency strips observed in giant pulses spectrum is found.

  13. Group theoretical description of artificial electromagnetic metamaterials

    E-print Network

    Huang, Jianyu

    Group theoretical description of artificial electromagnetic metamaterials Willie J. Padilla Los Alamos National Laboratory, MS K771, MPA-CINT, Los Alamos, New Mexico 87545 willie.padilla@bc.edu Present properties. References and links 1. D. R. Smith, W. J. Padilla, D. C. Vier, S. C. Nemat-Nasser, S. Schultz

  14. TWO UNCONVENTIONAL APPROACHES TO ELECTROMAGNETIC INVERSION

    E-print Network

    Snieder, Roel

    the feasibility of the inverse scattering series, which can effectively resolve the nonlinearity of an inverse problem, for the interpretation of electromagnetic data. The application of the inverse scat- tering to the true model. This study quantifies convergence conditions of the inverse scattering series and suggests

  15. Computer optimization of electromagnetic acoustic transducers

    Microsoft Academic Search

    M. Kaltenbacher; R. Lerch; H. Landes; K. Ettinger; B. Tittmann

    1998-01-01

    Electromagnetic acoustic transducers (EMATs) are well known devices that are commercially available. Their advantage is that they do not require a coupling medium and\\/or contact to the part being inspected; the disadvantage is their low transduction efficiency. In order to optimize their efficiency, the EMATs are best customized to their particular application with special attention to the material properties and

  16. Underground Anomaly Detection by Electromagnetic Shock Waves

    Microsoft Academic Search

    Amit S. Kesar

    2011-01-01

    A method for the detection of underground anoma- lies by electromagnetic (EM) shock waves is presented. Following Grischkowsky et al. (Phys. Rev. Lett., vol. 59, pp. 1663-1666, 1987), an EM shock wave will develop in a dielectric medium by exciting a pulse which leaks into the dielectric bulk from a transmission line. A shock wave occurs when the group velocity

  17. Electromagnetic properties of viscous charged fluids

    NASA Astrophysics Data System (ADS)

    Forcella, Davide; Zaanen, Jan; Valentinis, Davide; van der Marel, Dirk

    2014-07-01

    We provide a general theoretical framework to describe the electromagnetic properties of viscous charged fluids, consisting, for example, of electrons in certain solids or plasmas. We confirm that finite viscosity leads to multiple modes of evanescent electromagnetic waves at a given frequency, one of which is characterized by a negative index of refraction, as previously discussed in a simplified model by one of the authors. In particular, we explain how optical spectroscopy can be used to probe the viscosity. We concentrate on the impact of this on the coefficients of refraction and reflection at the sample-vacuum interface. Analytical expressions are obtained relating the viscosity parameter to the reflection and transmission coefficients of light. We demonstrate that finite viscosity has the effect to decrease the reflectivity of a metallic surface, while the electromagnetic field penetrates more deeply. While on a phenomenological level there are similarities to the anomalous skin effect, the model presented here requires no particular assumptions regarding the corpuscular nature of the charge liquid. A striking consequence of the branching phenomenon into two degenerate modes is the occurrence in a half-infinite sample of oscillations of the electromagnetic field intensity as a function of distance from the interface.

  18. Maxwell's electromagnetic theory and special relativity.

    PubMed

    Hall, Graham

    2008-05-28

    This paper presents a brief history of electromagnetic theory from ancient times up to the work of Maxwell and the advent of Einstein's special theory of relativity. It is divided into five convenient periods and the intention is to describe these developments for the benefit of a lay scientific audience and with the minimum of technical detail. PMID:18218598

  19. Accuracy Assessment for AG500, Electromagnetic Articulograph

    ERIC Educational Resources Information Center

    Yunusova, Yana; Green, Jordan R.; Mefferd, Antje

    2009-01-01

    Purpose: The goal of this article was to evaluate the accuracy and reliability of the AG500 (Carstens Medizinelectronik, Lenglern, Germany), an electromagnetic device developed recently to register articulatory movements in three dimensions. This technology seems to have unprecedented capabilities to provide rich information about time-varying…

  20. Scattering of Electromagnetic Waves, Theories and Applications

    Microsoft Academic Search

    Leung Tsang; Jin Au Kong; Kung-Hau Ding

    2000-01-01

    A timely and authoritative guide to the state of the art of wave scattering Scattering of Electromagnetic Waves offers in three volumes a complete and up-to-date treatment of wave scattering by random discrete scatterers and rough surfaces. Written by leading scientists who have made important contributions to wave scattering over three decades, this new work explains the principles, methods, and

  1. Electromagnetic field interactions with biological systems

    SciTech Connect

    Frey, A.H. (Randomline Inc., Huntingdon Valley, PA (United States))

    1993-02-01

    This is a report on Symposia organized by the International Society for Bioelectricity and presented at the 1992 FASEB Meeting. The presentations summarized here were intended to provide a sampling of new and fruitful lines of research. The theme topics for the Symposia were cancer, neural function, cell signaling, pineal gland function, and immune system interactions. Living organisms are complex electrochemical systems that evolved over billions of years in a world with a relatively simple weak magnetic field and with few electromagnetic energy emitters. As is characteristic of living organisms, they interacted with and adapted to this environment of electric and magnetic fields. In recent years there has been a massive introduction of equipment that emits electromagnetic fields in an enormous range of new frequencies, modulations, and intensities. As living organisms have only recently found themselves immersed in this new and virtually ubiquitous environment, they have not had the opportunity to adapt to it. This gives biologists the opportunity to use these electromagnetic fields as probes to study the functioning of living systems. This is a significant opportunity, as new approaches to studying living systems so often provide the means to make great leaps in science. In recent years, a diversity of biologists have carried out experiments using electromagnetic fields to study the function of living cells and systems. This approach is now becoming quite fruitful and is yielding data that are advancing our knowledge in diverse areas of biology. 25 refs., 6 figs., 3 tabs.

  2. The distribution of electromagnetic field in anisotropic brain tissue

    Microsoft Academic Search

    Youlin Geng; Xiuqin Zhu; Xinbao Wu; Peinan Jiao; Junmei Fan

    2000-01-01

    Some formulae are obtained for computing the electromagnetic field in anisotropic brain tissue using the Finite-Difference Time-Domain method (FDTD Method). A estimate is given about the field in anisotropic brain tissue with this formulae and one of the absorbing boundary conditions. A conclusion is made which is useful for electromagnetic compatibility and for considering the interaction between electromagnetic waves and

  3. Electromagnetic Actuator Control: A Linear Parameter-Varying (LPV) Approach

    Microsoft Academic Search

    Alexandru Forrai; Takaharu Ueda; Takashi Yumura

    2007-01-01

    This paper deals with system identification and control of a nonlinear electromagnetic actuator, which can be used in many practical applications: electromagnetic valve actuators of combustion engines, artificial heart actuators, magnetic levitation, electromagnetic brakes, etc. The considered practical control problem requires accurate control of the moving armature between two extreme positions. The main objective is to assure small contact velocity,

  4. Errors-in-variables problems in transient electromagnetic mineral exploration

    E-print Network

    Braslavsky, Julio H.

    Errors-in-variables problems in transient electromagnetic mineral exploration K. Lau, J. H in transient electromagnetic mineral exploration. A specific sub-problem of interest in this area-based transient electromagnetic (TEM) surveying using an Australian-developed technology known as GeoferretTM [1

  5. Application of Non-stationary EIV Methods to Transient Electromagnetic

    E-print Network

    Braslavsky, Julio H.

    Application of Non-stationary EIV Methods to Transient Electromagnetic Mineral Exploration K. Lau to a problem arising in transient electromagnetic mineral exploration. The proposed technique is used of EIV meth- ods to a model estimation problem encountered in tran- sient electromagnetic (TEM) mineral

  6. Electromagnetic actuator to reduce vibration sources Thibaut Chailloux*

    E-print Network

    Paris-Sud XI, Université de

    Electromagnetic actuator to reduce vibration sources Thibaut Chailloux* , L. Morel* , F. Sixdenier), hydraulic or pneumatic actuators, electromagnetic actuators [1], piezoelectric actuators. As part of a study to compensate a vibration on an aircraft engine for which an electromagnetic actuator was recommended. (The

  7. Electromagnetic measurements of duodenal digesta flow in cannulated sheep

    E-print Network

    Paris-Sud XI, Université de

    Electromagnetic measurements of duodenal digesta flow in cannulated sheep C. PONCET, M. IVAN M of duodenal digesta flow were made in sheep implanted with an electromagnetic flowmeter probe on the ascending to frequent oscillation of the digesta. It was concluded that accurate quantitative electromagnetic

  8. Genetic algorithm optimization applied to electromagnetics: a review

    Microsoft Academic Search

    Daniel S. Weile; Eric Michielssen

    1997-01-01

    Genetic algorithms are on the rise in electromagnetics as design tools and problem solvers because of their versatility and ability to optimize in complex multimodal search spaces. This paper describes the basic genetic algorithm and recounts its history in the electromagnetics literature. Also, the application of advanced genetic operators to the field of electromagnetics is described, and design results are

  9. Electromagnetic Waves Propagation in 3D Plasma Configurations

    E-print Network

    Electromagnetic Waves Propagation in 3D Plasma Configurations Pavel Popovich, W. Anthony Cooper such method is based on heating the plasma by electromagnetic waves with various frequencies. Wave behaviour that allows to simulate mode-conversion effects. The wave equation is formulated in terms of electromagnetic

  10. Electromagnetic models of the lightning return stroke Yoshihiro Baba1

    E-print Network

    Florida, University of

    Electromagnetic models of the lightning return stroke Yoshihiro Baba1 and Vladimir A. Rakov2, and characterization of the Earth's electromagnetic environment, as well as studying lightning interaction with various to as electromagnetic models. These models are relatively new and most rigorous of all models suitable for computing

  11. Electromagnetic characterization of PCB cards for mobile phones

    E-print Network

    Boyer, Edmond

    Electromagnetic characterization of PCB cards for mobile phones Ali Jazzar(*), Edith Clavel state, more the price linked to the EMC (Electromagnetic Compatibility) requirements is important .Thus the electromagnetic perturbations inside and outside the structure. The required CAD tool to achieve this modeling

  12. Electromagnetics, 26:335, 2006 Copyright Taylor & Francis Group, LLC

    E-print Network

    Anlage, Steven

    Electromagnetics, 26:3­35, 2006 Copyright © Taylor & Francis Group, LLC ISSN: 0272-6343 print/1532 the statistical properties of the impedance (Z) and scattering (S) matrices of open electromagnetic cavities. Introduction The problem of the coupling of electromagnetic radiation in and out of structures is a general one

  13. Cascade control strategy design for electromagnetic guidance system

    Microsoft Academic Search

    Jeng-Dao Lee; Zhi-Bin Wang; Jia-Qi Lu; Xuan-Ren Chen; Rou-Yong Duan

    2011-01-01

    This work simulates lateral motion in magnetic levitation (maglev) transportation systems using a novel electromagnetic guidance device. First, current control modules, a pulse-width-modulation (PWM) controller and buck converter, are used for driving electromagnets. The electromagnetic guidance system, which has two current control modules, a gap controller, and a bipolar switching mechanism, controls the gap between the moving platform and rail.

  14. ECE 202 Fall 2006 Introduction to Engineering Electromagnetics (3)

    E-print Network

    Gilchrist, James F.

    Textbooks: Fundamentals 1. J. A. Kong, Electromagnetic Wave Theory, EMW (2002). 2. C. Balanis, Advanced, Fundamental of Engineering Electromagnetics, Prentice Hall (2003). Nice and concise treatment of elementary EM, Electromagnetic Waves, Prentice Hall (2000). Among the most advanced EM textbook for ECE 203-level. 5. D. H

  15. The response functions of electromagnetic wave logs and their applications

    Microsoft Academic Search

    Guanglong Xing; Shande Yang

    2006-01-01

    A fundamental feature of the electromagnetic wave logs is the logging response (phase difference and amplitude ratio) dependent on the both dielectric constant and conductivity in general. We derived the response functions (RF) of the electromagnetic wave logs and proposed their fast algorithm based on an integral equation of electromagnetic field and a weak scattering approximation. Using the fast algorithm

  16. ECE 203 Spring 2012 Engineering Electromagnetics Waves (3)

    E-print Network

    Gilchrist, James F.

    ). Additional Advanced Textbooks: Fundamentals 1. J. A. Kong, Electromagnetic Wave Theory, EMW (2002). 2. CECE 203 ­ Spring 2012 Engineering Electromagnetics Waves (3) Lecture Time: Spring 2012, Monday, and A. S. Inan, Electromagnetic Waves, Prentice Hall (2000). Useful EM textbook for ECE 203-level. 2. D

  17. OKHEP9809 Modebymode summation for the zero point electromagnetic

    E-print Network

    Milton, Kim

    OKHEP­98­09 Mode­by­mode summation for the zero point electromagnetic energy of an infinite the zero point energy of the electromagnetic field is calculated for the boundary conditions given energy is doubtless of interest. In recent papers [3,4] the zero point energy of the electromagnetic

  18. A new inversion method for dissipating electromagnetic problem

    E-print Network

    Cherkaev, Elena

    A new inversion method for dissipating electromagnetic problem Elena Cherkaev Abstract The paper electromagnetic problem for a dissipating medium. The problem is to reconstruct the dielectric permittivity by applied electromagnetic sources. Problems of this type arise in geophys- ical surface and borehole

  19. An inverse electromagnetic scattering problem for , Fioralba Cakoni2

    E-print Network

    Cakoni, Fioralba

    An inverse electromagnetic scattering problem for cavity Fang Zeng1 , Fioralba Cakoni2 and Jiguang@desu.edu, cakoni@math.udel.edu and jsun@desu.edu Abstract. We consider the inverse electromagnetic scattering Publishing for peer review 11 August 2011 #12;An inverse electromagnetic scattering problem for cavity 2 1

  20. Pade Approximations in Inverse Homogenization and Numerical Simulation of Electromagnetic

    E-print Network

    Cherkaev, Elena

    Pad“e Approximations in Inverse Homogenization and Numerical Simulation of Electromagnetic Fields and in numerical simulation of time- domain electromagnetic fields in composites. It is assumed that the scale governing the electromagnetic fields are of convolution type. We use rational Pad“e approximation to derive

  1. Marine controlled-source elec-tromagnetic (CSEM) sounding is

    E-print Network

    Key, Kerry

    Marine controlled-source elec- tromagnetic (CSEM) sounding is a new tool available to geophysi- ground sediment provides an electromagnetic (EM) target, suggesting the use of electromagnetic methods above the seafloor (~100 m) and an alternating electromagnetic field is transmitted along the antenna

  2. Syllabus PHY 424/ELE 324 ELECTROMAGNETICS I/Fall 2009

    E-print Network

    Movileanu, Liviu

    1 Syllabus PHY 424/ELE 324 ELECTROMAGNETICS I/Fall 2009 Professor Dr. Liviu Movileanu, E description This course is the first half of a two-semester sequence in Electromagnetics, and deals with the most fundamental concepts of the laws of electromagnetism. You will learn about static electric

  3. Synthetic aperture controlled source electromagnetics R. Snieder,1

    E-print Network

    Snieder, Roel

    Click Here for Full Article Synthetic aperture controlled source electromagnetics Y. Fan,1 R; accepted 7 June 2010; published 9 July 2010. [1] Controlled source electromagnetics (CSEM) has been used. Rosenquist (2010), Syn- thetic aperture controlled source electromagnetics, Geophys. Res. Lett., 37, L13305

  4. Electromagnetic interaction in the theory of straight strings

    SciTech Connect

    Nikitin, I.N.; Pron`ko, G.P. [State Research Center Institute for High-Energy Physics, Protvino (Russian Federation)

    1995-06-01

    A scheme is proposed for including electromagnetic interaction into the theories of stretched relativistic objects. In the theory of the straight string, the operator of electromagnetic interaction is constructed, and form factors of electromagnetic transitions are calculated. 6 refs., 1 fig.

  5. An electromagnetics course with EMC applications for computer engineering students

    Microsoft Academic Search

    CHRISTOPHER W. TRUEMAN

    1990-01-01

    When computer engineering students follow a different (separate) program of study from the electrical engineering students, only a single course in engineering electromagnetics can be accommodated in the computer engineering (CE) core program. An outline for a course on electromagnetics for computer engineering is given combining traditional electromagnetics topics with definitions, concepts, and discussions drawn from EMC. In this way

  6. Electromagnetic wave propagation prediction using spatial statistics: experimental validation

    E-print Network

    Libre de Bruxelles, Université

    - The spatial statistics formalism is adapted to electromagnetic wave propagation analysis. Field pat- ternsElectromagnetic wave propagation prediction using spatial statistics: experimental validation Ph, as it is often the case. To speed up the electromagnetic wave propagation prediction, a solution would

  7. Electromagnetically-Induced Transparency of Magnetized Plasma: New Approach to Electromagnetic Energy Compression and Particle Acceleration

    Microsoft Academic Search

    Gennady Shvets

    2004-01-01

    Magnetized plasma is completely opaque to electromagnetic waves propagating along the magnetic field when the wave frequency matches the electron cyclotron frequency. Remarkably, electron cyclotron absorption can be cancelled by adding a weak magnetic undulator, resulting in an Undulator-Induced Transparency (UIT) of the plasma^3-5. UIT is the plasma analog of the electromagnetically-induced transparency (EIT) of the atomic medium. Likewise, UIT

  8. Nonreciprocal Electromagnetic Devices in Gyromagnetic Photonic Crystals

    NASA Astrophysics Data System (ADS)

    Li, Zhi-Yuan; Liu, Rong-Juan; Gan, Lin; Fu, Jin-Xin; Lian, Jin

    2014-01-01

    Gyromagnetic photonic crystal (GPC) offers a promising way to realize robust transport of electromagnetic waves against backscattering from various disorders, perturbations and obstacles due to existence of unique topological electromagnetic states. The dc magnetic field exerting upon the GPC brings about the time-reversal symmetry breaking, splits the band degeneracy and opens band gaps where the topological chiral edge states (CESs) arise. The band gap can originate either from long-range Bragg-scattering effect or from short-range localized magnetic surface plasmon resonance (MSP). These topological edge states can be explored to construct backscattering-immune one-way waveguide and other nonreciprocal electromagnetic devices. In this paper we review our recent theoretical and experimental studies of the unique electromagnetic properties of nonreciprocal devices built in GPCs. We will discuss various basic issues like experimental instrumental setup, sample preparations, numerical simulation methods, tunable properties against magnetic field, band degeneracy breaking and band gap opening and creation of topological CESs. We will investigate the unidirectional transport properties of one-way waveguide under the influence of waveguide geometries, interface morphologies, intruding obstacles, impedance mismatch, lattice disorders, and material dissipation loss. We will discuss the unique coupling properties between one-wave waveguide and resonant cavities and their application as novel one-way bandstop filter and one-way channel-drop filter. We will also compare the CESs created in the Bragg-scattering band gap and the MSP band gap under the influence of lattice disorders. These results can be helpful for designing and exploring novel nonreciprocal electromagnetic devices for optical integration and information processing.

  9. The continuing challenge of electromagnetic launch

    SciTech Connect

    Cowan, M.; Cnare, E.C.; Duggin, B.W.; Kaye, R.J.; Marder, B.M.; Shokair, I.R.

    1993-07-01

    Interest in launching payloads through the atmosphere to ever higher velocity is robust. For hundreds of years, guns and rockets have been improved for this purpose until they are now considered to be near to their performance limits. While the potential of electromagnetic technology to increase launch velocity has been known since late in the nineteenth century, it was not until about 1980 that a sustained and large-scale effort was started to exploit it. Electromagnetic launcher technology is restricted here to mean only that technology which establishes both a current density, J, and a magnetic field, B, within a part of the launch package, called the armature, so that J {times} B integrated over the volume of the armature is the launching force. Research and development activity was triggered by the discovery that high velocity can be produced with a simple railgun which uses an arc for its armature. This so called ``plasma-armature railgun`` has been the launcher technology upon which nearly all of the work has focused. Still, a relatively small parallel effort has also been made to explore the potential of electromagnetic launchers which do not use sliding contacts on stationary rails to establish current in the armature. One electromagnetic launcher of this type is called an induction coilgun because armature current is established by electromagnetic induction. In this paper, we first establish terminology which we will use not only to specify requirements for successful endoatmospheric launch but also to compare different launcher types. Then, we summarize the statuses of the railgun and induction coilgun technologies and discuss the issues which must be resolved before either of these launchers can offer substantial advantage for endoatomospheric launch.

  10. EEL 4473 Electromagnetic Fields and Applications II Text: Sadiku, M.N.O. Elements of Electromagnetics, 5th

    E-print Network

    Fang, Yuguang "Michael"

    EEL 4473 Electromagnetic Fields and Applications II Fall 2014 Text: Sadiku, M.N.O. Elements of Electromagnetics, 5th ed., Oxford Rakov, V.A. Electromagnetic Fields and Applications II, Course Packet (available. Antennas, Ch. 13 8 lectures, test - Hertzian dipole - Half-wave dipole and quarter-wave monopole - Small

  11. OPTI 501, Electromagnetic Waves (3) Vector fields, Maxwell's equations, electromagnetic field energy, wave equations, free-space

    E-print Network

    Arizona, University of

    OPTI 501, Electromagnetic Waves (3) Vector fields, Maxwell's equations, electromagnetic field, Oxford, 1983. 5) Jin Au Kong, Electromagnetic Wave Theory, EMW Publishing, Cambridge, MA, 2000. 6) M. V and mirrors, expression for the EM field momentum and mometum density. 3. Wave equation and fundamental

  12. IEEE TRANSACTIONS ON ELECTROMAGNETIC COMPATIBILITY, VOL. 49, NO. 3, AUGUST 2007 661 Novel Planar Electromagnetic Bandgap Structures

    E-print Network

    Ramahi, Omar

    IEEE TRANSACTIONS ON ELECTROMAGNETIC COMPATIBILITY, VOL. 49, NO. 3, AUGUST 2007 661 Novel Planar Electromagnetic Bandgap Structures for Mitigation of Switching Noise and EMI Reduction in High-Speed Circuits Jie Qin, Omar M. Ramahi, and Victor Granatstein, Life Member, IEEE Abstract--Planar electromagnetic

  13. Electronic systems failures and anomalies attributed to electromagnetic interference

    NASA Technical Reports Server (NTRS)

    Leach, R. D. (editor); Alexander, M. B. (editor)

    1995-01-01

    The effects of electromagnetic interference can be very detrimental to electronic systems utilized in space missions. Assuring that subsystems and systems are electrically compatible is an important engineering function necessary to assure mission success. This reference publication will acquaint the reader with spacecraft electronic systems failures and anomalies caused by electromagnetic interference and will show the importance of electromagnetic compatibility activities in conjunction with space flight programs. It is also hoped that the report will illustrate that evolving electronic systems are increasingly sensitive to electromagnetic interference and that NASA personnel must continue to diligently pursue electromagnetic compatibility on space flight systems.

  14. Electronic systems failures and anomalies attributed to electromagnetic interference

    NASA Astrophysics Data System (ADS)

    Leach, R. D.; Alexander, M. B.

    1995-07-01

    The effects of electromagnetic interference can be very detrimental to electronic systems utilized in space missions. Assuring that subsystems and systems are electrically compatible is an important engineering function necessary to assure mission success. This reference publication will acquaint the reader with spacecraft electronic systems failures and anomalies caused by electromagnetic interference and will show the importance of electromagnetic compatibility activities in conjunction with space flight programs. It is also hoped that the report will illustrate that evolving electronic systems are increasingly sensitive to electromagnetic interference and that NASA personnel must continue to diligently pursue electromagnetic compatibility on space flight systems.

  15. A strong permanent magnet-assisted electromagnetic undulator

    DOEpatents

    Halbach, K.

    1987-01-30

    This invention discloses an improved undulator comprising a plurality of electromagnet poles located along opposite sides of a particle beam axis with alternate north and south poles on each side of the beam to cause the beam to wiggle or undulate as it travels generally along the beam axis and permanent magnets spaced adjacent the electromagnetic poles on each side of the axis of said particle beam in an orientation sufficient to reduce the saturation of the electromagnet poles whereby the field strength of the electromagnet poles can be increased beyond the normal saturation levels of the electromagnetic poles. 4 figs.

  16. A new adaptive hybrid electromagnetic damper: modelling, optimization, and experiment

    NASA Astrophysics Data System (ADS)

    Asadi, Ehsan; Ribeiro, Roberto; Behrad Khamesee, Mir; Khajepour, Amir

    2015-07-01

    This paper presents the development of a new electromagnetic hybrid damper which provides regenerative adaptive damping force for various applications. Recently, the introduction of electromagnetic technologies to the damping systems has provided researchers with new opportunities for the realization of adaptive semi-active damping systems with the added benefit of energy recovery. In this research, a hybrid electromagnetic damper is proposed. The hybrid damper is configured to operate with viscous and electromagnetic subsystems. The viscous medium provides a bias and fail-safe damping force while the electromagnetic component adds adaptability and the capacity for regeneration to the hybrid design. The electromagnetic component is modeled and analyzed using analytical (lumped equivalent magnetic circuit) and electromagnetic finite element method (FEM) (COMSOL® software package) approaches. By implementing both modeling approaches, an optimization for the geometric aspects of the electromagnetic subsystem is obtained. Based on the proposed electromagnetic hybrid damping concept and the preliminary optimization solution, a prototype is designed and fabricated. A good agreement is observed between the experimental and FEM results for the magnetic field distribution and electromagnetic damping forces. These results validate the accuracy of the modeling approach and the preliminary optimization solution. An analytical model is also presented for viscous damping force, and is compared with experimental results The results show that the damper is able to produce damping coefficients of 1300 and 0–238 N s m?1 through the viscous and electromagnetic components, respectively.

  17. Electromagnetic and hadronic interactions of ultrarelativistic nuclei

    SciTech Connect

    Pshenichnov, I. A., E-mail: pshenich@inr.ru; Karpechev, E. V., E-mail: karpeche@inr.ru; Kurepin, A. B. [Russian Academy of Sciences, Institute for Nuclear Research (Russian Federation); Mishustin, I. N. [J.-W. Goethe University, Frankfurt Institute for Advanced Studies (Germany)

    2011-01-15

    Beam nuclei accelerated at the Large Hadron Collider (LHC) at CERN are lost due to interactions with the counter-rotating beam, residual gas, and accelerator elements. Proper modelling of the beam transport and radiation load on accelerator components requires reliable prediction of the yields of nuclear fragments produced in electromagnetic dissociation and hadronic fragmentation of beam nuclei. We investigate electromagnetic and hadronic fragmentation of lead nuclei in collisions with various nuclei and single electrons at the injection and collision energies of the LHC. The consideration is based on the RELDIS and abrasion-ablation models. Since this approach well describes Pb fragmentation data at 30 and 158 A GeV, its validity for Pb nuclei at the LHC collision energy is also expected.

  18. Historical electromagnetic propagation condition database description

    NASA Astrophysics Data System (ADS)

    Patterson, W. L.

    1987-09-01

    Described is an electromagnetic propagation conditions climatological database, a subset of which is employed by the Historical Electromagnetic Propagation Conditions Summary Function (HEPC) within the Tactical Environmental Support System (TESS). The HEPC function generates a climatological description of the refractive conditions for user-specified geographic location. The climatological description is composed of five parts: a percent occurrence of enhanced surface-to-surface radar detection, electronic support measures (EMS) intercept and communications range, a surface-based duct summary, an elevated duct summary, an evaporation duct histogram, and a general meteorology summary. The statistics displayed by the HEPC function are derived from two meteorological databases, the Radiosonde Data Analysis II assembled by the GTE Sylvania Corporation and the Duct63 assembled by the National Climatic Data Center. Prior to the discussion of HEPC database construction, it is appropriate to describe these two sources of data.

  19. Electromagnetic inverse applications for functional brain imaging

    SciTech Connect

    Wood, C.C.

    1997-10-01

    This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). This project addresses an important mathematical and computational problem in functional brain imaging, namely the electromagnetic {open_quotes}inverse problem.{close_quotes} Electromagnetic brain imaging techniques, magnetoencephalography (MEG) and electroencephalography (EEG), are based on measurements of electrical potentials and magnetic fields at hundreds of locations outside the human head. The inverse problem is the estimation of the locations, magnitudes, and time-sources of electrical currents in the brain from surface measurements. This project extends recent progress on the inverse problem by combining the use of anatomical constraints derived from magnetic resonance imaging (MRI) with Bayesian and other novel algorithmic approaches. The results suggest that we can achieve significant improvements in the accuracy and robustness of inverse solutions by these two approaches.

  20. Electromagnetic scattering by pyramidal and wedge absorber

    NASA Technical Reports Server (NTRS)

    Dewitt, Brian T.; Burnside, Walter D.

    1988-01-01

    Electromagnetic scattering from pyramidal and wedge absorbers used to line the walls of modern anechoic chambers is measured and compared with theoretically predicted values. The theoretical performance for various angles of incidence is studied. It is shown that a pyramidal absorber scatters electromagnetic energy more as a random rough surface does. The apparent reflection coefficient from an absorber wall illuminated by a plane wave can be much less than the normal absorber specifications quoted by the manufacturer. For angles near grazing incidence, pyramidal absorbers give a large backscattered field from the pyramid side-faces or edges. The wedge absorber was found to give small backscattered fields for near-grazing incidence. Based on this study, some new guidelines for the design of anechoic chambers are advocated because the specular scattering models used at present do not appear valid for pyramids that are large compared to the wavelength.

  1. Electromagnetic interactions in quantum Hall ferromagnets

    NASA Astrophysics Data System (ADS)

    Ray, Rashmi

    1998-11-01

    The ?=1 quantum Hall ground state in materials like GaAs is known to be ferromagnetic in nature. The exchange part of the Coulomb interaction provides the required attractive force to align the electronic spins spontaneously. The gapless Goldstone modes are the angular deviations of the magnetization vector from its fixed ground state orientation. Furthermore, the system supports electrically charged spin skyrmion configurations. It has been claimed in the literature that these skyrmions have half-integral spin owing to the presence of a topological Hopf term in the effective action governing the spin excitations. However, it has also been claimed that the derivation leading to this term is somewhat flawed. In this article, we demonstrate the existence of this term unambiguously. Furthermore, we investigate the electromagnetic interactions of the spin excitations and obtain a compact expression for the leading nonminimal electromagnetic coupling of these degrees of freedom.

  2. Pulsed thrust measurements using electromagnetic calibration techniques

    SciTech Connect

    Tang Haibin; Shi Chenbo; Zhang Xin'ai; Zhang Zun; Cheng Jiao [School of Astronautics, Beijing University of Aeronautics and Astronautics, Beijing 100191 (China)

    2011-03-15

    A thrust stand for accurately measuring impulse bits, which ranged from 10-1000 {mu}N s using a noncontact electromagnetic calibration technique is described. In particular, a permanent magnet structure was designed to produce a uniform magnetic field, and a multiturn coil was made to produce a calibration force less than 10 mN. The electromagnetic calibration force for pulsed thrust measurements was linear to the coil current and changed less than 2.5% when the distance between the coil and magnet changed 6 mm. A pulsed plasma thruster was first tested on the thrust stand, and afterward five single impulse bits were measured to give a 310 {mu}N s average impulse bit. Uncertainty of the measured impulse bit was analyzed to evaluate the quality of the measurement and was found to be 10 {mu}N s with 95% credibility.

  3. Complete transformer model for electromagnetic transients

    SciTech Connect

    Leon, F. de; Semlyen, A. (Univ. of Toronto, Ontario (Canada))

    1994-01-01

    A complete, three phase transformer model for the calculation of electromagnetic transients is presented. The model consists of a set of state equations solved with the trapezoidal rule of integration in order to obtain an equivalent Norton circuit at the transformer terminals. Thus the transformer model can be easily interfaced with an electromagnetic transients program. Its main features are: (a) the basic elements for the winding model are the turns, (b) the complete model includes the losses due to eddy currents in the windings and in the iron core, (c) the solution of the state equations is obtained in decoupled iterations. For validation, the frequency response of the model is compared with tests on several transformers. Applications to the calculation of transients are given for illustration.

  4. A 3.5 Tesla Laboratory Electromagnet

    NASA Astrophysics Data System (ADS)

    Pooke, D. M.; Chamritski, V.; Gibson, S.; Fee, M.; King, T.; Staines, M. P.; Flower, N. E.; Buckley, R. G.

    2004-06-01

    We report the design and construction of a laboratory electromagnet utilizing HTS coils in an iron yoke with a magnetic flux density of 3.5 Tesla in a 50-mm air-gap. With continuing improvement in the performance of HTS "BSCCO" wire, several niche HTS magnet applications have become viable at current wire prices. In this instance, the HTS conductor confers the advantages of high field strength combined with compact size and energy efficiency, in an electromagnet of a format suitable for many materials' characterization techniques, such as vibrating-sample magnetometry, for which the current magnet will be employed. The magnet employs four HTS coils, with a total of 1.6 km of BSCCO wire, which are conduction cooled using a single-stage Gifford-McMahon cryocooler, delivering approximately 25 W of cooling power at the target 35 K operating temperature; HTS current leads are utilized to minimize heat leak to the cryogenic environment.

  5. Complex Relativity: Gravity and Electromagnetic Fields

    E-print Network

    Roman Teisseyre; Mariusz Bialecki

    2005-06-06

    We present new aspects of the electromagnetic field by introducting the natural potentials. These natural potentials are suitable for constructing the first order distortions of the metric tensor of Complex Relativity - the theory combining the General Relativity with the electromagnetic equations. A transition from antisymmetric tensors to the symmetric ones helps to define the natural potentials; their form fits a system of the Dirac matrices and this representation leads to distortion of the metric tensor. Our considerations have originated from the recent progresses in the asymmetric continuum theories. One version of such theories assumes an existence of the antisymmetric strain and stress fields; these fields originate due to some kind of internal friction in a continuum medium which have elastic bonds related to rotations of the particles.

  6. A Connection between Gravitation and Electromagnetism

    E-print Network

    D. M. Snyder

    2000-02-16

    It is argued that there is a connection between the fundamental forces of electromagnetism and gravitation. This connection occurs because of: 1) the fundamental significance of the finite and invariant velocity of light in inertial reference frames in the special theory, and 2) the reliance of the general theory of relativity upon the special theory of relativity locally in spacetime. The connection between the fundamental forces of electromagnetism and gravitation follows immediately from these two points. A brief review is provided of: 1) the role of the finite and invariant velocity of light in inertial reference frames in the special theory, and 2) certain fundamental concepts of the general theory, including its reliance on the special theory locally.

  7. Electromagnetic detection of a perfect carpet cloak.

    PubMed

    Shi, Xihang; Gao, Fei; Lin, Xiao; Zhang, Baile

    2015-01-01

    It has been shown that a spherical invisibility cloak originally proposed by Pendry et al. can be electromagnetically detected by shooting a charged particle through it, whose underlying mechanism stems from the asymmetry of transformation optics applied to motions of photons and charges [PRL 103, 243901 (2009)]. However, the conceptual three-dimensional invisibility cloak that exactly follows specifications of transformation optics is formidably difficult to implement, while the simplified cylindrical cloak that has been experimentally realized is inherently visible. On the other hand, the recent carpet cloak model has acquired remarkable experimental development, including a recently demonstrated full-parameter carpet cloak without any approximation in the required constitutive parameters. In this paper, we numerically investigate the electromagnetic radiation from a charged particle passing through a perfect carpet cloak and propose an experimentally verifiable model to demonstrate symmetry breaking of transformation optics. PMID:25997798

  8. Electromagnetic radiations associated with major earthquakes

    NASA Astrophysics Data System (ADS)

    Fujinawa, Yukio; Takahashi, Kozo

    Measurements of subsurface electric field changes have been conducted by means of borehole antennas. Changes in the number of pulse-like signals in a VLF band (seismic radio wave signals: SRS) evolved in close accordance with the occurrence of the earthquakes. The propagation of the long distance more than 500 km indicates the occurrence of waveguide mode propagation between the ionosphere and the ground. The time evolution of the number of the pulses indicates that there are two in the SRS: one emitted directly from the epicentral area and the other, coming induced by nonlinear interaction in the ionosphere, indirectly. These results indicate that the phenomena may be used to predict the time, location and magnitude of imminent earthquakes. Moreover, prominent electromagnetic field changes are observed just at the time of the great earthquake providing clear evidence that the fault motion is accompanied by electromagnetic radiation.

  9. Dielectric Sensors Based on Electromagnetic Energy Tunneling

    PubMed Central

    Siddiqui, Omar; Kashanianfard, Mani; Ramahi, Omar

    2015-01-01

    We show that metallic wires embedded in narrow waveguide bends and channels demonstrate resonance behavior at specific frequencies. The electromagnetic energy at these resonances tunnels through the narrow waveguide channels with almost no propagation losses. Under the tunneling behavior, high-intensity electromagnetic fields are produced in the vicinity of the metallic wires. These intense field resonances can be exploited to build highly sensitive dielectric sensors. The sensor operation is explained with the help of full-wave simulations. A practical setup consisting of a 3D waveguide bend is presented to experimentally observe the tunneling phenomenon. The tunneling frequency is predicted by determining the input impedance minima through a variational formula based on the Green function of a probe-excited parallel plate waveguide. PMID:25835188

  10. Electromagnetic model for propagation through clouds

    NASA Astrophysics Data System (ADS)

    Seker, S. S.

    Electromagnetic propagation through a sparse distribution of lossy dielectric particles in a cloud is investigated. A mathematical model is developed to aid in the interpretation of the interaction data obtained by electromagnetic remote probing of mixed ice crystal and waterdrop clouds. Such clouds can contain many possible crystal forms, most notably thin long cylinder, bullets, and flat plate crystals. Bistatic reflectivity and attenuation are computed for waves of selected polarizations passing through clouds with specified size, shape, and distributions. The proposed formulation is matrix and stochastic in nature, and easily accomodates arbitrary polarization states. It allows complete characterization of medium depolarization effects from hydrometers (e.g., attenuation, isolation, and shape shift). The results obtained are of interest in connection with the study of the effects of clouds on microwave or millimeter-wave communications.

  11. The Linear Bicharacteristic Scheme for Electromagnetics

    NASA Technical Reports Server (NTRS)

    Beggs, John H.

    2001-01-01

    The upwind leapfrog or Linear Bicharacteristic Scheme (LBS) has previously been implemented and demonstrated on electromagnetic wave propagation problems. This paper extends the Linear Bicharacteristic Scheme for computational electromagnetics to model lossy dielectric and magnetic materials and perfect electrical conductors. This is accomplished by proper implementation of the LBS for homogeneous lossy dielectric and magnetic media and for perfect electrical conductors. Heterogeneous media are modeled through implementation of surface boundary conditions and no special extrapolations or interpolations at dielectric material boundaries are required. Results are presented for one-dimensional model problems on both uniform and nonuniform grids, and the FDTD algorithm is chosen as a convenient reference algorithm for comparison. The results demonstrate that the explicit LBS is a dissipation-free, second-order accurate algorithm which uses a smaller stencil than the FDTD algorithm, yet it has approximately one-third the phase velocity error. The LBS is also more accurate on nonuniform grids.

  12. Development of a laced electromagnetic wiggler

    SciTech Connect

    Christensen, T.C.; Burns, M.J.; Deis, G.A.; Parkison, C.D.; Prosnitz, D.; Halbach, K.

    1987-01-01

    The laced electromagnetic wiggler is a new concept being developed to attain higher magnetic fields, shorter wavelengths, and larger gaps for the induction-linear accelerator, free-electron-laser (FEL) program. In the laced wiggler design, permanent magnets are located (''laced'') between the electromagnetic coils to increase the reverse-bias flux in the iron pole beyond that possible with only pole-edge (''side'') permanent magnets. This increase in reverse-bias flux allows wiggler operation at midplane magnetic field intensities comparable to those of a hybrid permanent magnet/steel wiggler, but with field adjustability over a specified range. The maximum field intensity and tuning range are selected, within limits, for specific design requirements. We have designed and tested a one-period prototype of this concept with promising results.

  13. Status of ASIC readout for electromagnetic calorimeter

    E-print Network

    Elmaddin Guliyev

    2012-10-18

    The next generation experiment in high energy particle physics will be International Linear Collider of electron and positron at the TeV scale. The experiment is aim to search the Higgs particle and to measure its properties. The physics program required the detector with high performance. One of the central detector is a Electromagnetic calorimeter, is going to measure the energy and position of high energy photons. Fine granularity and compactness brings to utilize the Si-W sampling detector. Due to high granularity the electromagnetic calorimeter will comprise of the order of $10^8$ readout cells. The recent developed prototype ASIC chip with 36 channels will be used readout of Si-W ECAL. The performance study will discuss of developed ASIC readout with ECAL prototype, use of pulse generator.

  14. Enabling technologies for petascale electromagnetic accelerator simulation

    NASA Astrophysics Data System (ADS)

    Lee, Lie-Quan; Akcelik, Volkan; Chen, Sheng; Ge, Lixin; Prudencio, Ernesto; Schussman, Greg; Uplenchwar, Ravi; Ng, Cho; Ko, Kwok; Luo, Xiaojun; Shephard, Mark

    2007-07-01

    The SciDAC2 accelerator project at SLAC aims to simulate an entire three-cryomodule radio frequency (RF) unit of the International Linear Collider (ILC) main Linac. Petascale computing resources supported by advances in Applied Mathematics (AM) and Computer Science (CS) and INCITE Program are essential to enable such very large-scale electromagnetic accelerator simulations required by the ILC Global Design Effort. This poster presents the recent advances and achievements in the areas of CS/AM through collaborations.

  15. Glass valveless micropump using electromagnetic actuation

    Microsoft Academic Search

    Christophe Yamahata; Frédéric Lacharme; Martin A. M. Gijs

    2005-01-01

    We present a valveless micropump in glass, which is magnetically actuated using the sinusoidal current of an external electromagnet. We employ a powder blasting microerosion process for microstructuring the glass substrates and fusion bonding for assembly of the multi-layered microfluidic chip. The reciprocating type micropump contains two nozzle\\/diffuser elements and a poly(dimethylsiloxane) membrane with embedded permanent magnet. The micropump is

  16. A PMMA valveless micropump using electromagnetic actuation

    Microsoft Academic Search

    Christophe Yamahata; C. Lotto; E. Al-Assaf; M. A. M. Gijs

    2005-01-01

    We have fabricated and characterized a polymethylmethacrylate (PMMA) valveless micropump. The pump consists of two diffuser elements and a polydimethylsiloxane (PDMS) membrane with an integrated composite magnet made of NdFeB magnetic powder. A large-stroke membrane deflection (~200 µm) is obtained using external actuation by an electromagnet. We present a detailed analysis of the magnetic actuation force and the flow rate of

  17. The Electromagnetic Spectrum: X-Rays

    NSDL National Science Digital Library

    This site provided by National Aeronautics and Space Administration contains an introduction to X-rays and their uses in medicine and astronomy. Descriptions of the first X-ray observations, how they are used to visualize parts of the body, and results from X-ray astronomy are provided. The site contains striking astronomical images made with X-rays. Also provided are links to similar sites on the other electromagnetic spectrum regions.

  18. Current driven electromagnetic ion cyclotron instability

    Microsoft Academic Search

    D. W. Forslund; J. M. Kindel; M. A. Stroscio

    1979-01-01

    A detailed investigation of the electron-current-driven electro-magnetic ion cyclotron instability is presented which extends the original work on the subject by Stix (1962). An infinite uniform collisionless Maxwellian plasma embedded in a constant dc magnetic field is assumed. Analytical derivation of the critical drift velocity spans the range of ion-beta from about 0.001 to 0.1. An important result is that

  19. Electromagnetic Casimir Forces in Elliptic Cylinder Geometries

    E-print Network

    Noah Graham

    2013-03-26

    The scattering theory approach makes it possible to carry out exact calculations of Casimir energies in any geometry for which the scattering T-matrix and a partial wave expansion of the free Green's function are available. We implement this program for the case of a perfectly conducting elliptic cylinder, thereby completing the set of geometries where electromagnetic scattering is separable. Particular emphasis is placed on the case of zero radius, where the elliptic cylinder reduces to a strip.

  20. Rectangular Pulsed Laser-Electromagnetic Hybrid Accelerator

    NASA Astrophysics Data System (ADS)

    Kishida, Yoshiaki; Katayama, Masahiro; Horisawa, Hideyuki

    2010-10-01

    Experimental investigation of impulse-bit and propellant consumption rate, or mass shot, per single pulse discharge was conducted to characterize the thrust performance of the rectangular laser-electromagnetic hybrid acceleration thruster with various propellant materials. From the result, alumina propellant showed significantly superior performance. The largest values of the measured impulse-bit, specific impulse and thrust efficiency were 49 ?Nsec, 6,200 sec and 22%, respectively.

  1. Rectangular Pulsed Laser-Electromagnetic Hybrid Accelerator

    SciTech Connect

    Kishida, Yoshiaki; Katayama, Masahiro; Horisawa, Hideyuki [Department of Aeronautical and Astronautical Engineering, Tokai University Hiratsuka, Kanagawa, 259-1292 (Japan)

    2010-10-13

    Experimental investigation of impulse-bit and propellant consumption rate, or mass shot, per single pulse discharge was conducted to characterize the thrust performance of the rectangular laser-electromagnetic hybrid acceleration thruster with various propellant materials. From the result, alumina propellant showed significantly superior performance. The largest values of the measured impulse-bit, specific impulse and thrust efficiency were 49 {mu}Nsec, 6,200 sec and 22%, respectively.

  2. The experiment 705 electromagnetic shower calorimeter

    Microsoft Academic Search

    L. Antoniazzi; M. Arenton; Z. Cao; T. Y. Chen; S. Conetti; B. Cox; S. Delchamps; L. Fortney; K. Guffey; M. Haire; M. He; P. Ioannou; C. M. Jenkins; D. J. Judd; C. Kourkoumelis; A. Manousakis-Katsikakis; J. Kuzminski; T. Lecompte; A. Marchionni; P. O. Mazur; C. T. Murphy; P. Pramantiotis; R. Rameika; L. Resvanis; M. Rosati; J. Rosen; C. H. Shen; Q. Shen; A. Simard; R. Smith; L. Spiegel; D. Stairs; Y. Tan; R. J. Tesarek; T. Turkington; L. Turnbull; F. Turkot; S. Tzamarias; G. Voulgaris; D. E. Wagoner; C. Wang; J. Weckel; W. Yang; N. Yao; N. Zhang; X. Zhang; G. Zioulas; B. Zou

    1993-01-01

    Experiment 705 at Fermi National Accelerator Laboratory has designed, built, and operated a large acceptance, highly segmented electromagnetic shower calorimeter using SF5 lead glass, SCG1-C scintillating glass, and two types of gas-based fine-grained hodoscopes. The calorimeter was used to reconstruct photons and electrons with energies ranging from a few GeV\\/c2 to over 100 GeV\\/c2 in 300 GeV\\/c pion and proton

  3. Electromagnetic or other directed energy pulse launcher

    DOEpatents

    Ziolkowski, Richard W. (Livermore, CA)

    1990-01-01

    The physical realization of new solutions of wave propagation equations, such as Maxwell's equations and the scaler wave equation, produces localized pulses of wave energy such as electromagnetic or acoustic energy which propagate over long distances without divergence. The pulses are produced by driving each element of an array of radiating sources with a particular drive function so that the resultant localized packet of energy closely approximates the exact solutions and behaves the same.

  4. On electromagnetic waves in chiral media

    Microsoft Academic Search

    D. L. Jaggard; A. R. Mickelson; C. H. Papas

    1979-01-01

    We analyze the propagation of electromagnetic waves through chiral media, i.e., through composite media consisting of macroscopic\\u000a chiral objects randomly embedded in a dielectric. The peculiar effects that such media have on the polarization properties\\u000a of the waves are placed in evidence. To demonstrate the physical basis of these effects, a specific example, chosen for its\\u000a analytical simplicity, is worked

  5. Bobbing and kicks in electromagnetism and gravity

    SciTech Connect

    Gralla, Samuel E.; Harte, Abraham I.; Wald, Robert M. [Enrico Fermi Institute and Department of Physics, University of Chicago, 5640 South Ellis Avenue, Chicago, Illinois 60637 (United States)

    2010-05-15

    We study systems analogous to binary black holes with spin in order to gain some insight into the origin and nature of 'bobbing' motion and 'kicks' that occur in this system. Our basic tool is a general formalism for describing the motion of extended test bodies in an external electromagnetic field in curved spacetime and possibly subject to other forces. We first show that bobbing of exactly the type as observed in numerical simulations of the binary black hole system occurs in a simple system consisting of two spinning balls connected by an elastic band in flat spacetime. This bobbing may be understood as arising from the difference between a spinning body's 'lab frame centroid' and its true center of mass, and is purely 'kinematical' in the sense that it will appear regardless of the forces holding two spinning bodies in orbit. Next, we develop precise rules for relating the motion of charged bodies in a stationary external electromagnetic field in flat spacetime with the motion of bodies in a weakly curved stationary spacetime. We then consider the system consisting of two orbiting charges with magnetic dipole moment and spin at a level of approximation corresponding to 1.5 post-Newtonian order. Here we find that considerable amounts of momentum are exchanged between the bodies and the electromagnetic field; however, the bodies store this momentum entirely as ''hidden'' mechanical momentum, so that the interchange does not give rise to any net bobbing. The net bobbing that does occur is due solely to the kinematical spin effect, and we therefore argue that the net bobbing of the electromagnetic binary is not associated with possible kicks. We believe that this conclusion holds in the gravitational case as well.

  6. Time-domain electromagnetics and its applications

    Microsoft Academic Search

    C. L. Bennett; G. F. Ross

    1978-01-01

    The purpose of this paper is to introduce the reader to the elments of time-domain electromagnetics, which includes baseband-pulse technology and target-signature analysis. Baseband pulses are video or carrierless pulses of very short duration, whose spectral content is concentrated primarily from zero frequency through the microwave region of the spectrum. Work in baseband technology began more than ten years ago

  7. Numerical Modelling for Electromagnetic Processing of Materials

    Microsoft Academic Search

    Valdis Bojarevics; Koulis Pericleous

    2007-01-01

    Electromagnetic processing of materials (EPM) is one of the most widely practiced and fast growing applications of magnetic\\u000a and electric forces to fluid flow. EPM is encountered in both industrial processes and laboratory investigations. Applications\\u000a range in scale from nano-particle manipulation to tonnes of liquid metal treated in the presence of various configurations\\u000a of magnetic fields. Some of these processes

  8. Oscillatory system of the jet electromagnetic vibrator

    NASA Astrophysics Data System (ADS)

    Bogdanov, E.; Rikkonen, S.; Nomokonova, Yu

    2014-10-01

    The article describes the system of nonlinear differential equations of the jet electromagnetic vibrator, designed to activate Newtonian and non-Newtonian fluids. The authors formulated the principles of designing electrical and hydro-mechanical components of the device based on the viscosity and density of the process liquid. The article describes experimental frequency characteristics of the system for liquids with the different rheological properties.

  9. Electromagnetic Field Fluctuations in the Early Universe

    Microsoft Academic Search

    V. I. Savchenko; N. J. Fisch

    1998-01-01

    Employing the fluctuation-dissipation theorem (FDT) to analyze an equilibrium plasma of the Early Universe at z ~ 10^11, Tajima et al Ap. J. 390, 309, (1992) calculate that the plasma is capable of sustaining large low frequency electromagnetic fields, ^1\\/2 ~ 10^14 G. A more accurate description in this regime suggests that certain assumptions of the FDT are violated. In

  10. Vibrotactile using micromachined electromagnetic actuators array

    NASA Astrophysics Data System (ADS)

    Talbi, A.; Ducloux, O.; Tiercelin, N.; Deblock, Y.; Pernod, P.; Preobrazhensky, V.

    2006-04-01

    One motivating application of this technology is the development of a tactile display interface, where discrete mechanical actuators apply vibratory excitation at discrete locations on the skin. Specifically, this paper describes the development fabrication and characterization of a 4 x 4 micro-actuator array of vibrating pixels for fingertip tactile communication. The vibrting pixels are generated by using an electromagnetic microresonator. The fabrication sequence and the actuation performance of the array are also presented.

  11. Computational modeling of nonlinear electromagnetic phenomena

    NASA Technical Reports Server (NTRS)

    Goorjian, Peter M.; Taflove, Allen

    1992-01-01

    A new algorithm has been developed that permits, for the first time, the direct time integration of the full-vector nonlinear Maxwell's equations. This new capability permits the modeling of linear and nonlinear, instantaneous and dispersive effects in the electric polarization material media. Results are presented of first-time calculations in 1D of the propagation and collision of femtosecond electromagnetic solitons that retain the optical carrier.

  12. Electromagnetic momentum in frontiers of modern physics

    Microsoft Academic Search

    Gianfranco Spavieri; Jesśs Erazo; Arturo Sanchez; Felix Aguirre; George T. Gillies; Miguel Rodriguez

    2008-01-01

    We review the role of the momentum of the electromagnetic (EM) fields P\\u000a e in several areas of modern physics. P\\u000a e represents the EM interaction in equations for matter and light waves propagation. As an application of wave propagation\\u000a properties, a first order optical experiment which tests the speed of light in moving rarefied gases is presented. Within\\u000a a

  13. Degrees of freedom of an electromagnetic wave

    Microsoft Academic Search

    Rafael Piestun; David A. Miller

    1999-01-01

    We present a rigorous formalism for evaluating the degrees of freedom (d.o.f.) in communication with electromagnetic waves. We show that, although in principle there is an infinity of d.o.f., the effective number is finite. This is in agreement with the restricted classical theories. We further show that the best transmitting functions are the solutions of a specific eigenvalue equation. The

  14. Scaling the electromagnetically driven explosive shock simulator

    NASA Technical Reports Server (NTRS)

    Persh, Robert I.

    1987-01-01

    A heavy payload electromagnetically driven explosive shock simulator, referred to as EDESS-3, has been assembled and characterized at the Navel research Weapons Center. EDESS-3 is the logical outgrowth of the earlier EDESS 1 and 2 simulator work which explored the use of electrical pulse power technology for the generation of explosive like shocks. The features of the EDESS-3 are presented, and designs for the next generation of EDESS machines are introduced.

  15. Velocity damper for electromagnetically levitated materials

    SciTech Connect

    Fox, R.J.

    1992-12-31

    A system for damping oscillatory and spinning motions induced in an electromagnetically levitated material. Two opposed field magnets are located orthogonally to the existing levitation coils for providing a DC quadrupole field (cusp field) around the material. The material used for generating the DC quadrupole field must be nonconducting to avoid eddy-current heating and of low magnetic permeability to avoid distorting the induction fields providing the levitation.

  16. Optimization of an electromagnetic comb drive actuator

    Microsoft Academic Search

    S. Schonhardt; J. G. Korvink; J. Mohr; U. Hollenbach; U. Wallrabe

    2009-01-01

    We present the first electromagnetic comb drive actuator which allows for over 100?m of linear actuator motion at large air gap widths of 25?m at 300 coil windings, a structural height of 400?m and for an applied current of 8mA. Previously reported designs require very narrow air gaps of 3?m at structural heights of up to 1mm [K. Fischer, H.

  17. Underground anomaly detection by electromagnetic shock waves

    Microsoft Academic Search

    Amit S. Kesar

    2011-01-01

    A method for the detection of underground anomalies by electromagnetic (EM) shock waves was described in [IEEE Trans. Ant. Prop. vol. 59, no. 1, pp. 149–153, January 2011]. Following Grischkowsky et al.[Phys. Rev. Lett., vol. 59, pp. 1663–1666, 1987], an EM shock wave will develop in a dielectric medium by exciting a pulse which leaks into the dielectric bulk from

  18. Engineering electromagnetic metamaterials and methanol fuel cells

    NASA Astrophysics Data System (ADS)

    Yen, Tajen

    2005-07-01

    Electromagnetic metamaterials represent a group of artificial structures, whose dimensions are smaller than subwavelength. Due to electromagnetic metamaterials' collective response to the applied fields, they can exhibit unprecedented properties to fascinate researchers' eyes. For instance, artificial magnetism above terahertz frequencies and beyond, negative magnetic response, and artificial plasma lower than ultraviolet and visible frequencies. Our goal is to engineer those novel properties aforementioned at interested frequency regions and further optimize their performance. To fulfill this task, we developed exclusive micro/nano fabrication techniques to construct magnetic metamaterials (i.e., split-ring resonators and L-shaped resonators) and electric metamaterials (i.e., plasmonic wires) and also employed Taguchi method to study the optimal design of electromagnetic metamaterials. Moreover, by integrating magnetic and electric metamaterials, we have been pursuing to fabricate so-called negative index media---the Holy Grail enables not only to reverse conventional optical rules such as Snell's law, Doppler shift, and Cerenkov radiation, but also to smash the diffraction limit to realize the superlensing effect. In addition to electromagnetic metamaterials, in this dissertation we also successfully miniaturize silicon-based methanol fuel cells by means of micro-electrical-mechanical-system technique, which promise to provide an integrated micro power source with excellent performance. Our demonstrated power density and energy density are one of the highest in reported documents. Finally, based on the results of metamaterials and micro fuel cells, we intend to supply building blocks to complete an omnipotent device---a system with sensing, communication, computing, power, control, and actuation functions.

  19. Photino bremsstrahlung in intense electromagnetic fields

    NASA Astrophysics Data System (ADS)

    Kurilin, Alexander V.; Ternov, Aleksey I.

    1996-02-01

    We calculate the probability for the emission of a pair of photinos by an electron moving in a background electromagnetic field. The rate of the process e -> e?~?~ is estimated at different values of the field strength and electron energies. Comparing the cooling rate of some astrophysical objects via photino bremsstrahlung with another competing energy-loss mechanism we find new constraints on the selectron massesMe~R =Me~L >= 89.4 GeV.

  20. The electromagnetic calorimeter of the NOMAD experiment

    Microsoft Academic Search

    D. Autiero; M. Baldo-Ceolin; G. Barichello; V. Bianchi-Bonaiti; F. Bobisut; A. Cardini; P. W. Cattaneo; V. Cavasinni; C. Conta; T. Del Prete; A. De Santo; L. Di Lella; R. Ferrari; V. Flaminio; M. Fraternali; D. Gibin; S. N. Gninenko; A. Guglielmi; E. Iacopini; A. V. Kovzelev; L. La Rotonda; A. Lanza; M. Laveder; C. Lazzeroni; M. Livan; M. Mezzetto; D. Orestano; F. Pastore; E. Pennacchio; R. Petti; G. Polesello; G. Renzoni; A. Rimoldi; C. Roda; A. Sconza; C. Sobczynski; M. Valdata-Nappi; M. Vascon; V. Vercesi; L. Visentin; S. A. Volkov

    1996-01-01

    A description is given of the NOMAD electromagnetic calorimeter, consisting of 875 lead-glass counters read out by two-stage photomultipliers and a low noise electronic chain. The detector operates in a 0.4 T magnetic field transverse to the counter axis. The paper discusses the design criteria, the lead-glass characteristics, the properties of the read out chain and provides a summary of