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.
NSDL National Science Digital Library
Michael Horton
2009-05-30
In this investigation, students will construct electromagnets and test to see which variables make them stronger. Although elementary and middle school teachers are expected to have done this activity with their classes, teachers of younger students often
NSDL National Science Digital Library
VU Bioengineering RET Program,
In this activity, the students will complete the grand challenge and design an electromagnet to separate steel from aluminum for the recycler. In order to do this, students compare the induced magnetic field of an electric current with the magnetic field of a permanent magnet and must make the former look like the latter. They discover that looping the current produces the desired effect and find ways to further strengthen the magnetic field.
NSDL National Science Digital Library
David P. Stern
2004-09-23
These pages, part of From Stargazers to Starships, explain electromagnetic waves and sunlight. Information inlcudes physiological and spectral color, spectral lines, the electromagnetic field work by Maxwell, the discovery of radio waves by Hertz, and photons and Einsteins relation. Stargazers also has detailed lesson plans accompanying these sections.
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)
NSDL National Science Digital Library
Fendt, Walter
This simulation shows a plane polarized electromagnetic wave propagating in positive x direction. The vectors of the electric field (red) are parallel to the y axis, the vectors of the magnetic field (blue) are parallel to the z axis. This applet illustrates the behavior of the fields in electromagnetic waves. This is part of a large collection of physics applets available in several languages.
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.
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.
... off radio-frequency energy (RF), a form of electromagnetic radiation. Scientists need to do more research on this before they can say for sure. NIH: National Institute of Environmental Health Sciences
Electromagnetic Theory 1 /56 Electromagnetic Theory
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
Milton, Graeme W
2008-01-01
The electromagnetic analog of an elastic spring-mass network is constructed. These are called electromagnetic circuits and linear electrical circuits correspond to a subclass of them. They consist of thin triangular magnetic components joined at the edges by cylindrical dielectric components. Some of the edges can be terminal edges to which electric fields are applied. The response is measured in terms of the free currents associated with the terminal edges. The relation between the terminal electric fields and the terminal free currents is governed by a symmetric complex matrix W. In the case where all the terminal edges are disjoint, and the frequency is fixed, a complete characterization is obtained of all possible response matrices W, both in the lossless and lossy cases. There are also dual electromagnetic circuits consisting of thin triangular dielectric components joined at the edges by cylindrical magnetic components
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.
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.
A USGS hydrologist conducts a near-surface electromagnetic induction survey to characterize the shallow earth. The survey was conducted as part of an applied research effort by the USGS Office of Groundwater Branch of Geophysics at Camp Rell, Connecticut, in 2008....
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...
C. Furse
2004-01-01
The focus of this issue's column is teaching electromagnetic compatibility. A summary of resources for this topic is found in the article by Levent Sevgi, and additional online course materials are summarized on the IEEE AP-S education course material repository Web site: www.ece.utah.edu\\/?cfurse\\/APS\\/course.htm. The column also provides a set of suggestions that are applicable to a variety of courses on
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.
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.
Electromagnetic microactuators
NASA Astrophysics Data System (ADS)
Bttgenbach, S.; Al-Halhouli, A. T.; Feldmann, M.; Seidemann, V.; Waldschik, A.
2013-05-01
High precision microactuators have become key elements for many applications of MEMS, for example for positioning and handling systems as well as for microfluidic devices. Electromagnetic microactuators exhibit considerable benefits such as high forces, large deflections, low input impedances and thus, the involvement of only low voltages. Most of the magnetic microactuators developed so far are based on the variable reluctance principle and use soft magnetic materials. Since the driving force of such actuators is proportional to their volume, they require structures with rather great heights and aspect ratios. Therefore, the development of new photo resists, which allow UV exposure of thick layers of resist, has been essential for the advancement of variable reluctance microactuators. On the other hand, hard magnetic materials have the potential for larger forces and larger deflections. Accordingly, polymer magnets, in which micro particles of hard magnetic material are suspended in a polymer matrix, have been used to fabricate permanent magnet microactuators. In this paper we give an overview of sophisticated electromagnetic microactuators which have been developed in our laboratory in the framework of the Collaborative Research Center "Design and Manufacturing of Active Microsystems". In particular, concept, fabrication and test of variable reluctance micro stepper motors, of permanent magnet synchronous micromotors and of microactuators based on the Lorentz force principle will be described. Special emphasis will be given to applications in lab-on-chip systems.
Electromagnetic topology: Characterization of internal electromagnetic coupling
NASA Technical Reports Server (NTRS)
Parmantier, J. P.; Aparicio, J. P.; Faure, F.
1991-01-01
The main principles are presented of a method dealing with the resolution of electromagnetic internal problems: Electromagnetic Topology. A very interesting way is to generalize the multiconductor transmission line network theory to the basic equation of the Electromagnetic Topology: the BLT equation. This generalization is illustrated by the treatment of an aperture as a four port junction. Analytical and experimental derivations of the scattering parameters are presented. These concepts are used to study the electromagnetic coupling in a scale model of an aircraft, and can be seen as a convenient means to test internal electromagnetic interference.
Hart, Gus
Electromagnetic Field Theory BO THID? UPSILON BOOKS #12;#12;ELECTROMAGNETIC FIELD THEORY #12;#12;Electromagnetic Field Theory BO THID? Swedish Institute of Space Physics and Department of Astronomy and Space, Sweden UPSILON BOOKS · COMMUNA AB · UPPSALA · SWEDEN #12;Also available ELECTROMAGNETIC FIELD THEORY
R. K. Matthews; S. A. Stepanek
1993-01-01
Electromagnetic wave testing, which represents a relatively new test technique that involves the union of several disciplines (aerothermodynamics, electromagnetics, materials\\/structures, and advanced diagnostics) is introduced. The essence of this new technique deals with the transmission and possible distortion of electromagnetic waves (RF or IR) as they pass through the bow shock, flow field, and electromagnetic window of a missile flying
NASA Astrophysics Data System (ADS)
Kolm, H.; Mongeau, P.; Williams, F.
1980-09-01
Recent advances in energy storage, switching and magnet technology make electromagnetic acceleration a viable alternative to chemical propulsion for certain tasks, and a means to perform other tasks not previously feasible. Applications include the acceleration of gram-size particles for hypervelocity research and the initiation of fusion by impact, a replacement for chemically propelled artillery, the transportation of cargo and personnel over inaccessible terrain, and the launching of space vehicles to supply massive space operations, and for the disposal of nuclear waste. The simplest launcher of interest is the railgun, in which a short-circuit slide or an arc is driven along two rails by direct current. The most sophisticated studied thus far is the mass driver, in which a superconducting shuttle bucket is accelerated by a line of pulse coils energized by capacitors at energy conversion efficiencies better than 90%. Other accelerators of interest include helical, brush-commutated motors, discrete coil arc commutated drivers, flux compression momentum transformers, and various hybrid electrochemical devices.
7. Electromagnetic relations 1 7. ELECTROMAGNETIC RELATIONS
7. Electromagnetic relations 1 7. ELECTROMAGNETIC RELATIONS Revised September 2005 by H.G. Spieler = 10-7 N A-2 ; c = 1 0 0 = 2.997 924 58 ? 108 m s-1 #12;2 7. Electromagnetic relations 7.1. Impedances of self-inductance L: Z = jL . Impedance of capacitance C: Z = 1/jC . Impedance of free space: Z = 0/ 0
Electromagnetic properties of neutrinos
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.
Investigation of electromagnetic welding
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 ...
Electromagnetic Interference (Emi)
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
Electromagnetic Measurements at RHIC
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
Electromagnetic Measurements at RHIC
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
Electromagnetic Abdulaziz Hanif
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
Electromagnetic structure of pion
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.
8.07 Electromagnetism II, Fall 2002
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, ...
Exploring the Electromagnetic Spectrum
NSDL National Science Digital Library
2014-09-18
Students learn the basics of the electromagnetic spectrum and how various types of electromagnetic waves are related in terms of wavelength and energy. In addition, they are introduced to the various types of waves that make up the electromagnetic spectrum including, radio waves, ultraviolet waves, visible light and infrared waves. These topics help inform students before they turn to designing solutions to an overarching engineering challenge question.
Perfect electromagnetic conductor
Ismo V. Lindell; Ari Sihvola
2005-01-01
In differential-form representation, the Maxwell equations are represented by simple differential relations between the electromagnetic two-forms and source three-forms while the electromagnetic medium is defined through a constitutive relation between the two-forms. The simplest of such relations expresses the electromagnetic two-forms as scalar multiples of one another. Because of its strange properties, the corresponding medium has been considered as nonphysical.
Meson electromagnetic form factors
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.
How Strong are Electromagnets?
NSDL National Science Digital Library
This is an activity about electromagnetism. Using a battery and a length of wire, learners will construct an electromagnet and investigate the number of paperclips the electromagnet can hold for an electromagnet with twenty loops of wire versus one with forty loops of wire. A six to twelve volt battery, a large nail or metal rod, and insulated wire are required for this activity. This is the fourth activity in the Exploring the Earth's Magnetic Field: An IMAGE Satellite Guide to the Magnetosphere educators guide.
NISTHB 150-11 NVLAP Electromagnetic Compatibility and Telecommunications Bethany Hackett Bradley. #12;NISTHB 150-11 NVLAP Electromagnetic Compatibility and Telecommunications Bethany Hackett Bradley Programs Dennis Camell Electromagnetics Division Physical Measurement Laboratory http://dx.doi.org/10
NSDL National Science Digital Library
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.
NSDL National Science Digital Library
This tutorial introduces students to the concepts of electromagnetic waves, wavelength, and the electromagnetic spectrum. Diagrams and written descriptions explain how wavelength is measured and explore the traditional divisions of the spectrum: radio, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays.
Tunability enhanced electromagnetic wiggler
Schlueter, Ross D. (Albany, CA); Deis, Gary A. (Livermore, CA)
1992-01-01
The invention discloses a wiggler used in synchrotron radiation sources and free electron lasers, where each pole is surrounded by at least two electromagnetic coils. The electromagnetic coils are energized with different amounts of current to provide a wide tunable range of the on-axis magnetic flux density, while preventing magnetic saturation of the poles.
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.
Electromagnetic Analysis: Concrete Results
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
Tunability enhanced electromagnetic wiggler
Schlueter, R.D.; Deis, G.A.
1992-03-24
The invention discloses a wiggler used in synchrotron radiation sources and free electron lasers, where each pole is surrounded by at least two electromagnetic coils. The electromagnetic coils are energized with different amounts of current to provide a wide tunable range of the on-axis magnetic flux density, while preventing magnetic saturation of the poles. 14 figs.
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
NASA Astrophysics Data System (ADS)
Matthews, R. K.; Stepanek, S. A.
Electromagnetic wave testing, which represents a relatively new test technique that involves the union of several disciplines (aerothermodynamics, electromagnetics, materials/structures, and advanced diagnostics) is introduced. The essence of this new technique deals with the transmission and possible distortion of electromagnetic waves (RF or IR) as they pass through the bow shock, flow field, and electromagnetic window of a missile flying at hypersonic speeds. Variations in gas density along the optical path can cause significant distortion of the electromagnetic waves and, therefore the missile seeker system may not effectively track the target. Two specific test techniques are described. The first example deals with the combining of a wind tunnel and an RF range while the second example discusses the complexities of evaluating IR seeker system performance.
Electromagnetism, Second Edition
NASA Astrophysics Data System (ADS)
Grant, I. S.; Phillips, W. R.
2003-09-01
The Manchester Physics Series General Editors: D. J. Sandiford; F. Mandl; A. C. Phillips Department of Physics and Astronomy, University of Manchester Properties of Matter B. H. Flowers and E. Mendoza Optics Second Edition F. G. Smith and J. H. Thomson Statistical Physics Second Edition F. Mandl Electromagnetism Second Edition I. S. Grant and W. R. Phillips Statistics R. J. Barlow Solid State Physics Second Edition J. R. Hook and H. E. Hall Quantum Mechanics F. Mandl Particle Physics Second Edition B. R. Martin and G. Shaw the Physics of Stars Second Edition A. C. Phillips Computing for Scientists R. J. Barlow and A. R. Barnett Electromagnetism, Second Edition is suitable for a first course in electromagnetism, whilst also covering many topics frequently encountered in later courses. The material has been carefully arranged and allows for flexi-bility in its use for courses of different length and structure. A knowledge of calculus and an elementary knowledge of vectors is assumed, but the mathematical properties of the differential vector operators are described in sufficient detail for an introductory course, and their physical significance in the context of electromagnetism is emphasised. In this Second Edition the authors give a fuller treatment of circuit analysis and include a discussion of the dispersion of electromagnetic waves. Electromagnetism, Second Edition features: The application of the laws of electromagnetism to practical problems such as the behaviour of antennas, transmission lines and transformers. Sets of problems at the end of each chapter to help student understanding, with hints and solutions to the problems given at the end of the book. Optional "starred" sections containing more specialised and advanced material for the more ambitious reader. An Appendix with a thorough discussion of electromagnetic standards and units. Recommended by many institutions. Electromagnetism. Second Edition has also been adopted by the Open University as the course book for its third level course on electromagnetism.
Gravito-electromagnetic resonances
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.
NSDL National Science Digital Library
2012-08-03
This interactive, online module reviews the basics of the the electromagnetic spectrum and makes the connection between radiation theory and the images we get from weather satellites. Students will learn about: the electromagnetic spectrum; electromagnetic waves; the electromagnetic spectrum and radiation theory; and how satellite radiometers "see" different sections of the spectrum. The module is part of an online course for grades 7-12 in satellite meteorology, which includes 10 interactive modules. The site also includes lesson plans developed by teachers and links to related resources. Each module is designed to serve as a stand-alone lesson, however, a sequential approach is recommended. Designed to challenge students through the end of 12th grade, middle school teachers and students may choose to skim or skip a few sections.
Geant4 Electromagnetic Physics
S. Chauvie; V. Grichine; P. Gumplinger; V. Ivanchenko; R. Kokoulin; S. Magni; M. Maire; P. Nieminen; M. G. Pia; A. Rybin; L. Urban
2001-01-01
An overview of the main features of Geant4 electromagnetic physics is presented. The role played by advanced software engineering methodologies and by Object Oriented technology is illustrated. The main physics functionalities are described.
Purely electromagnetic spacetimes
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.
The classical geometrization electromagnetism
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.
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)
Microslots : scalable electromagnetic instrumentation
Maguire, Yael G., 1975-
2004-01-01
This thesis explores spin manipulation, fabrication techniques and boundary conditions of electromagnetism to bridge the macroscopic and microscopic worlds of biology, chemistry and electronics. This work is centered around ...
Gravito-electromagnetic resonances
Tsagas, Christos G
2011-01-01
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...
An opening electromagnetic transducer
NASA Astrophysics Data System (ADS)
Sun, Yanhua; Kang, Yihua
2013-12-01
Tubular solenoids have been widely used without any change since an electrical wire was discovered to create magnetic fields by Hans Christian Oersted in 1820 and thereby the wire was first coiled as a helix into a solenoid coil by William Sturgeon in 1823 and was improved by Joseph Henry in 1829 [see http://www.myetymology.com/encyclopedia/History_of_the_electricity.html; J. M. D. Coey, Magnetism and Magnetic Materials (Cambridge University Press, New York, 2010); and F. Winterberg, Plasma Phys. 8, 541553 (1996)]. A magnetic control method of C-shaped carrying-current wire is proposed, and thereby a new opening electromagnetic transducer evidently differing from the traditional tubular solenoid is created, capable of directly encircling and centering the acted objects in it, bringing about convenient and innovative electromagnetic energy conversion for electromagnetic heating, electromagnetic excitation, physical information capture, and electro-mechanical motion used in science research, industry, and even biomedical activities.
Inverse problems in electromagnetics
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 ...
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.
EMACK electromagnetic launcher commissioning
NASA Astrophysics Data System (ADS)
Deis, D. W.; Scherbarth, D. W.; Ferrentino, G. L.
1984-03-01
The Laboratory Demonstration Electromagnetic Launcher Program (EMACK) was initiated in April 1979, with the objective to design, construct, and demonstrate a complete electromagnetic launcher (EML) system capable of accelerating projectiles of substantial mass to velocities significantly greater than those achievable with conventional chemical systems. The last hardware was installed in late 1981. During February 1982, a series of five test shots was made to evaluate the system's performance. Particular attention is given to the parameters of the final, as-built hardware, and the results of the commissioning tests. The results of these tests have demonstrated the viability of the components required for large scale electromagnetic launchers. It has been shown that large projectiles with velocities significantly greater than those achievable by chemical systems can be accelerated intact.
Aircraft electromagnetic compatibility
NASA Technical Reports Server (NTRS)
Clarke, Clifton A.; Larsen, William E.
1987-01-01
Illustrated are aircraft architecture, electromagnetic interference environments, electromagnetic compatibility protection techniques, program specifications, tasks, and verification and validation procedures. The environment of 400 Hz power, electrical transients, and radio frequency fields are portrayed and related to thresholds of avionics electronics. Five layers of protection for avionics are defined. Recognition is given to some present day electromagnetic compatibility weaknesses and issues which serve to reemphasize the importance of EMC verification of equipment and parts, and their ultimate EMC validation on the aircraft. Proven standards of grounding, bonding, shielding, wiring, and packaging are laid out to help provide a foundation for a comprehensive approach to successful future aircraft design and an understanding of cost effective EMC in an aircraft setting.
Electromagnetic properties of baryons
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.
Electromagnetic particle simulation codes
NASA Technical Reports Server (NTRS)
Pritchett, P. L.
1985-01-01
Electromagnetic particle simulations solve the full set of Maxwell's equations. They thus include the effects of self-consistent electric and magnetic fields, magnetic induction, and electromagnetic radiation. The algorithms for an electromagnetic code which works directly with the electric and magnetic fields are described. The fields and current are separated into transverse and longitudinal components. The transverse E and B fields are integrated in time using a leapfrog scheme applied to the Fourier components. The particle pushing is performed via the relativistic Lorentz force equation for the particle momentum. As an example, simulation results are presented for the electron cyclotron maser instability which illustrate the importance of relativistic effects on the wave-particle resonance condition and on wave dispersion.
Electromagnetic properties of baryons
T. Ledwig; J. Martin-Camalich; V. Pascalutsa; M. Vanderhaeghen
2011-05-03
We discuss the chiral behavior of 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^3 and p^4/Delta with Delta as the Delta(1232)-nucleon energy gap. We show that the magnetic moment of a resonance can be defined through 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 results for finite volume effects on the iso-vector anomalous magnetic moment.
Electromagnetic propulsion test facility
NASA Technical Reports Server (NTRS)
Gooder, S. T.
1984-01-01
A test facility for the exploration of electromagnetic propulsion concept is described. The facility is designed to accommodate electromagnetic rail accelerators of various lengths (1 to 10 meters) and to provide accelerating energies of up to 240 kiloJoules. This accelerating energy is supplied as a current pulse of hundreds of kiloAmps lasting as long as 1 millisecond. The design, installation, and operating characteristics of the pulsed energy system are discussed. The test chamber and its operation at pressures down to 1300 Pascals (10 mm of mercury) are described. Some aspects of safety (interlocking, personnel protection, and operating procedures) are included.
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.
Electromagnetic analysis and design of electromagnetic devices using permanent magnets
M. Nagrial; J. Rizk
2003-01-01
The design of electromagnetic devices requires accurate calculation of the design parameters. The finite element method is extensively employed in the design of electrical machines and other electromagnetic and magnetic systems. The finite element method provides an accurate and simple approach to parameters evaluation from the determination of electromagnetic field distribution. The details of designed permanent magnet machines and magnetic
Electromagnetically Induced Flows Michiel de Reus
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
8.07 Electromagnetism II, Fall 2005
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 ...
Electromagnetic shock absorber
S. Mirzaei; S. M. Saghaiannejad; V. Tahani; M. Moallem
2001-01-01
This paper introduces a novel passive suspension system for ground vehicles. The system is based a flexible electromagnetic shock absorber (EMSA). In the proposed system, it is attempted: (a) to select a variable high damping coefficient usable in a car; (b) physical dimensions and the geometry of EMSA not to be very different from mechanical shock absorbers; and (c) its
Global electromagnetic induction
R. G. Roberts
1986-01-01
Methods of analysis of long period geomagnetic variations (periods over a few hours), the available electromagnetic response function estimates, and the effect of lateral inhomogeneity within the Earth are reviewed. Recent advances in the inversion of response function data to produce conductivitydepth profiles are mentioned, and aspects of the inverse problem specific to global (spherical Earth) induction are discussed. There
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
Electromagnetic pulsar spindown
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.
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.
Electromagnetism and Gravitation
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.
Adaptive electromagnetic shunt damping
Dominik Niederberger; Sam Behrens; Andrew J. Fleming; S. O. R. Moheimani; Manfred Morari
2006-01-01
This paper presents a new type of passive vibration control: adaptive electromagnetic shunt damping. We propose a single-mode resonant shunt controller that adapts to environmental conditions using two different adaptation strategies. The first technique is based on minimizing the root mean square (RMS) vibration, while the second minimizes the phase difference between two measurable signals. An experimental comparison shows that
Electromagnetic radiations from rocks
Toshio Ogawa; Kazuo Oike; Taiji Miura
1985-01-01
To test the possibility of the emission of electromagnetic waves from rocks, experiments have been made to measure the electric field by using mainly granite samples that were struck together or struck by a hammer or a weight and were fractured by a bending moment. The wide-band (10 Hz to 100 kHz) waveforms of electric signals were digitally recorded. Roughly
Simple Superconducting "Permanent" Electromagnet
NASA Technical Reports Server (NTRS)
Israelson, Ulf E.; Strayer, Donald M.
1992-01-01
Proposed short tube of high-temperature-superconducting material like YBa2Cu3O7 acts as strong electromagnet that flows as long as magnetic field remains below critical value and temperature of cylinder maintained sufficiently below superconducting-transition temperature. Design exploits maximally anisotropy of high-temperature-superconducting material.
Noncontact Electromagnetic Vibration Source
NASA Technical Reports Server (NTRS)
Namkung, Min; Fulton, James P.; Wincheski, Buzz A.
1994-01-01
Metal aircraft skins scanned rapidly in vibration tests. Relatively simple combination of permanent magnets and electromagnet serves as noncontact vibration source for nondestructive testing of metal aircraft skins. In test, source excites vibrations, and vibration waveforms measured, then analyzed for changes in resonances signifying cracks and other flaws.
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.
S. Takada; T. Makimura; M. Matsubara
1986-01-01
This patent describes an electromagnetic fuel injector for an internal combustion engine. This device is seated in a valve housing with a fuel injection nozzle and a valve seat at its front end and a guide hole extending along its axis to contain the valve body. The valve body of this device includes a cylindrical slide unit which has a
Electromagnetic Momentum, Energy, and Mass
F. Rohrlich
1970-01-01
Electromagnetic systems of finite mass (m > 0) and of zero mass (m = 0) are considered. For both cases the electromagnetic energy and momentum are computed and are shown to lead to essentially different formulas. An invariant expression for the electromagnetic mass in m > 0 systems is derived. All m > 0 results are then specialized to the
Spectroscopy Interaction of electromagnetic radiation
Gerwert, Klaus
Spectroscopy 691 Interaction of electromagnetic radiation with atoms or molecules #12;Bacteriorhodopsin: a light-driven proton pump 486 #12;Electromagnetic Radiation 692 harmonic wave (Maxwell): y;Spectroscopy 691 Interaction of electromagnetic radiation with atoms or molecules two processes: emission
Computational Electronics and Electromagnetics
DeFord, J.F.
1993-03-01
The Computational Electronics and Electromagnetics thrust area is a focal point for computer modeling activities in electronics and electromagnetics in the Electronics Engineering Department of Lawrence Livermore National Laboratory (LLNL). Traditionally, they have focused their efforts in technical areas of importance to existing and developing LLNL programs, and this continues to form the basis for much of their research. A relatively new and increasingly important emphasis for the thrust area is the formation of partnerships with industry and the application of their simulation technology and expertise to the solution of problems faced by industry. The activities of the thrust area fall into three broad categories: (1) the development of theoretical and computational models of electronic and electromagnetic phenomena, (2) the development of useful and robust software tools based on these models, and (3) the application of these tools to programmatic and industrial problems. In FY-92, they worked on projects in all of the areas outlined above. The object of their work on numerical electromagnetic algorithms continues to be the improvement of time-domain algorithms for electromagnetic simulation on unstructured conforming grids. The thrust area is also investigating various technologies for conforming-grid mesh generation to simplify the application of their advanced field solvers to design problems involving complicated geometries. They are developing a major code suite based on the three-dimensional (3-D), conforming-grid, time-domain code DSI3D. They continue to maintain and distribute the 3-D, finite-difference time-domain (FDTD) code TSAR, which is installed at several dozen university, government, and industry sites.
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.
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.
Magnetism and Electromagnetism
NSDL National Science Digital Library
Kuphaldt, Tony R.
All About Circuits is a website that ??provides a series of online textbooks covering electricity and electronics.? 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 ?? 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).
Isotropic metamaterial electromagnetic lens
E. Verney; B. Sauviac; C. R. Simovski
2004-01-01
Several authors have recently exhibited the focusing activity in the domain of so-called electromagnetic lenses. These lenses are parallel-plate layers of metamaterials whose properties can be described in terms of negative index of refraction. Known works on this subject refer to 2D structures. This work is our first attempt to show the focusing effect by a parallel-plate layer of a
Gravitation and Electromagnetism
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.
Quaternion Gravi-Electromagnetism
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.
Banded electromagnetic stator core
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.
Banded electromagnetic stator core
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.
Banded electromagnetic stator core
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.
Banded electromagnetic stator core
Fanning, A.W.; Gonzales, A.A.; Patel, M.R.; Olich, E.E.
1996-06-11
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 figs.
Electromagnetic tornadoes in space
Chang, T.; Crew, G.B.; Retterer, J.M.
1988-01-01
The exotic phenomenon of energetic-ion conic formation by plasma waves in the magnetosphere is considered. Two particular transverse heating mechanisms are reviewed in detail; lower-hybrid energization of ions in the boundary layer of the plasma sheet and electromagnetic ion cyclotron resonance heating in the central region of the plasma sheet. Mean particle calculations, plasma simulations and analytical treatments of the heating processes are described.
Method of electromagnetic exploration
Nekut, A.G. Jr.
1987-05-05
A method is described of electromagnetic exploration comprising the following steps: obtaining measures of two horizontal components of the earth's magnetic field at each reference sites; obtaining a measure of the vertical component of the earth's magnetic field for at least one exploratory site; and determining a measure of a multidimensional earth resistivity structure by correlating the measures of horizontal and vertical components of the earth's magnetic field.
Fractional Electromagnetic Waves
J. F. Gmez; J. J. Rosales; J. J. Bernal; V. I. Tkach; M. Gua
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.
The KLOE electromagnetic calorimeter
M. Adinolfi; F. Ambrosino; A. Antonelli; M. Antonelli; F. Anulli; G. Barbiellini; G. Bencivenni; S. Bertolucci; C. Bini; C. Bloise; V. Bocci; F. Bossi; P. Branchini; G. Cabibbo; R. Caloi; P. Campana; M. Casarsa; G. Cataldi; F. Ceradini; F. Cervelli; P. Ciambrone; E De Lucia; P De Simone; G De Zorzi; S Dell'Agnello; A. Denig; A. Di Domenico; C. Di Donato; S Di Falco; A. Doria; O. Erriquez; A. Farilla; A. Ferrari; M. L Ferrer; G. Finocchiaro; C. Forti; A. Franceschi; P. Franzini; M. L Gao; C. Gatti; P. Gauzzi; A. Giannasi; S. Giovannella; E. Graziani; H. G Han; S. W Han; X. Huang; M. Incagli; L. Ingrosso; L. Keeble; W. Kim; C. Kuo; G. Lanfranchi; J. Lee-Franzini; T. Lomtadze; C. S Mao; M. Martemianov; W. Mei; R. Messi; S. Miscetti; S. Moccia; M. Moulson; S. Mller; F. Murtas; L. Pacciani; M. Palomba; M. Palutan; E. Pasqualucci; L. Passalacqua; A. Passeri; D. Picca; G. Pirozzi; L. Pontecorvo; M. Primavera; P. Santangelo; E. Santovetti; G. Saracino; R. D Schamberger; B. Sciascia; F. Scuri; I. Sfiligoi; P. Silano; T. Spadaro; E. Spiriti; L. Tortora; P. Valente; B. Valeriani; G. Venanzoni; A. Ventura; S. Wlfle; Y. Wu; Y. G Xie; P. F Zema; C. D Zhang; J. Q Zhang; P. P. Zhao
2002-01-01
The KLOE detector was designed primarily for the study of CP violation in neutral kaon decays at DA?NE, the Frascati ?-factory. The detector consists of a tracker and an electromagnetic calorimeter. A lead-scintillating-fiber sampling calorimeter satisfies best the requirements of the experiment, providing adequate energy resolution and superior timing accuracy. We describe in the following the construction of the calorimeter,
Gravito-electromagnetic analogies
NASA Astrophysics Data System (ADS)
Costa, L. Filipe O.; Natrio, Jos
2014-10-01
We reexamine and further develop different gravito-electromagnetic (GEM) analogies found in the literature, and clarify the connection between them. Special emphasis is placed in two exact physical analogies: the analogy based on inertial fields from the so-called "1+3 formalism", and the analogy based on tidal tensors. Both are reformulated, extended and generalized. We write in both formalisms the Maxwell and the full exact Einstein field equations with sources, plus the algebraic Bianchi identities, which are cast as the source-free equations for the gravitational field. New results within each approach are unveiled. The well known analogy between linearized gravity and electromagnetism in Lorentz frames is obtained as a limiting case of the exact ones. The formal analogies between the Maxwell and Weyl tensors are also discussed, and, together with insight from the other approaches, used to physically interpret gravitational radiation. The precise conditions under which a similarity between gravity and electromagnetism occurs are discussed, and we conclude by summarizing the main outcome of each approach.
Coherent hybrid electromagnetic field imaging
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.
Rutledge, Steven
Electromagnetic WavesElectromagnetic Waves In this chapter we will review selected properties of electromagnetic waves since radar involves the transmission, propagation and scattering of EM waves by various is the electrostatic force between two point charges. #12;Electromagnetic WavesElectromagnetic Waves Electric fields
Electromagnetic field and cosmic censorship
Koray Dzta?
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.
Electromagnetic Theory 3 Volume Set
NASA Astrophysics Data System (ADS)
Heaviside, Oliver
2011-09-01
Volume 1: Preface; 1. Introduction; 2. Outline of the electromagnetic connections; 3. The elements of vectorial algebra and analysis; 4. Theory of plane electromagnetic waves; Appendix. Volume 2: Preface; 5. Mathematics and the age of the earth; 6. Pure diffusion of electric displacement; 7. Electromagnetic waves and generalised differentiation; 8. Generalised differentiation and divergent series; Appendix. Volume 3: 9. Waves from moving sources; 10. Waves in the ether.
Electromagnetic field and cosmic censorship
Dzta?, Koray
2013-01-01
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.
Electromagnetic field and cosmic censorship
NASA Astrophysics Data System (ADS)
Dzta?, Koray
2014-04-01
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.
Achievable Transverse Cylindrical Electromagnetic Mode
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.
Electromagnetically controllable osteoclast activity.
Hong, Jung Min; Kang, Kyung Shin; Yi, Hee-Gyeong; Kim, Shin-Yoon; Cho, Dong-Woo
2014-05-01
The time-varying electromagnetic field (EMF) has been widely studied as one of the exogenous stimulation methods for improving bone healing. Our previous study showed that osteogenic differentiation of adipose-derived stem cells was accelerated by a 45-Hz EMF, whereas a 7.5-Hz EMF inhibited osteogenic marker expression. Accordingly, we hypothesized that each negative and positive condition for the osteogenic differentiation could inversely influence osteoclast formation and differentiation. Here, we demonstrated that osteoclast formation, differentiation, and activity can be regulated by altering the frequency of the electromagnetic stimulation, such as 7.5 (negative for osteogenic differentiation) and 45 Hz (positive for osteogenic differentiation). A 45 Hz EMF inhibited osteoclast formation whereas a 7.5-Hz EMF induced differentiation and activity. Osteoclastogenic markers, such as NFATc1, TRAP, CTSK, MMP9, and DC-STAMP were highly expressed under the 7.5-Hz EMF, while they were decreased at 45 Hz. We found that the 7.5-Hz EMF directly regulated osteoclast differentiation through ERK and p38 MAPK activation, whereas the EMF at 45 Hz suppressed RANKL-induced phosphorylation of I?B. Additionally, actin ring formation with tubules and bone resorptive activity were enhanced at 7.5 Hz through increased integrin ?3 expression. However, these were inhibited at 45 Hz. Although many questions remain unanswered, our study indicates that osteoclast formation and differentiation were controllable using physical tools, such as an EMF. It will now be of great interest to study the ill-defined correlation between electromagnetic conditions and osteoclast activities, which eventually could lead to determining the therapeutic characteristics of an EMF that will treat bone-related diseases. PMID:24556539
Electromagnetism on Anisotropic Fractals
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.
Advanced electromagnetic gun simulation
NASA Astrophysics Data System (ADS)
Brown, J. L.; George, E. B.; Lippert, J. R.; Balius, A. R.
1986-11-01
The architecture, software and application of a simulation system for evaluating electromagnetic gun (EMG) operability, maintainability, test data and performance tradeoffs are described. The system features a generic preprocessor designed for handling the large data rates necessary for EMG simulations. The preprocessor and postprocessor operate independent of the EMG simulation, which is viewed through windows by the user, who can then select the areas of the simulation desired. The simulation considers a homopolar generator, busbars, pulse shaping coils, the barrel, switches, and prime movers. In particular, account is taken of barrel loading by the magnetic field, Lorentz force and plasma pressure.
Electromagnetic Probes in PHENIX
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.
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.
Electromagnetic pump stator coil
Fanning, Alan W. (San Jose, CA); Dahl, Leslie R. (Livermore, CA)
1996-01-01
An electrical stator coil for an electromagnetic pump includes a continuous conductor strip having first and second terminals at opposite ends thereof and an intermediate section disposed therebetween. The strip is configured in first and second coil halves, with the first coil half including a plurality of windings extending from the first terminal to the intermediate section, and the second coil half including a plurality of windings extending from the second terminal to the intermediate section. The first and second coil halves are disposed coaxially, and the first and second terminals are disposed radially inwardly therefrom with the intermediate section being disposed radially outwardly therefrom.
Electromagnetic pump stator coil
Fanning, A.W.; Dahl, L.R.
1996-06-25
An electrical stator coil for an electromagnetic pump includes a continuous conductor strip having first and second terminals at opposite ends thereof and an intermediate section disposed therebetween. The strip is configured in first and second coil halves, with the first coil half including a plurality of windings extending from the first terminal to the intermediate section, and the second coil half including a plurality of windings extending from the second terminal to the intermediate section. The first and second coil halves are disposed coaxially, and the first and second terminals are disposed radially inwardly therefrom with the intermediate section being disposed radially outwardly therefrom. 9 figs.
Mathematical Tripos, Part IB : Electromagnetism 4 Electromagnetic induction
Mathematical Tripos, Part IB : Electromagnetism 4 Electromagnetic induction Recall the paragraph's theorem to a fixed curve C = S bounding a fixed open surface S. If we define the electromotive force (orS, (3) then we get Faraday's Law of induction E = - d dt . (4) This will be studied now. In chapter two
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.
Metamaterials beyond electromagnetism.
Kadic, Muamer; Bckmann, 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. PMID:24190877
Metamaterials beyond electromagnetism
NASA Astrophysics Data System (ADS)
Kadic, Muamer; Bckmann, 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 experimentall 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.
Localization of Classical Waves II: Electromagnetic Waves.
Localization of Classical Waves II: Electromagnetic Waves. Alexander Figotin \\Lambda Department We consider electromagnetic waves in a medium described by a position dependent dielectric constant at all times. Localization of electromagnetic waves is a consequence of Anderson localization
Electromagnetic neutrino: a short review
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.
Particle swarm optimization in electromagnetics
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
Exploration of the Electromagnetic Environment
ERIC Educational Resources Information Center
Fullekrug, M.
2009-01-01
The electromagnetic environment is composed of electric and magnetic fields which result from man-made and natural sources. An elementary experiment is described to explore the electromagnetic environment by measuring electric fields in the frequency range from approximately equal to 10 to 24 000 Hz. The equipment required to conduct the
Electromagnetic self interaction in strings
Brandon Carter
1997-04-30
To facilitate the treatment of electromagnetic effects in applications such as dynamically perturbed vortons, this work employs a covariantly formulated string-source Green measure to obtain a coherent relativistic scheme for describing the self interaction of electromagnetic currents in string models of a very general kind, at leading order in the relevant field gradients, using a regularised gradient operator given by $\\hat\
Electromagnetics laboratory annual report, 1994
I. V. Lindell; A. H. Sihvola
1995-01-01
Activities of the Electromagnetics Laboratory during 1994 are described in this report. As highlights of the output stand the monographs Electromagnetic Waves in Chiral and Bi-Isotropic Media (Artech House, Boston) and History of Electrical Engineering (Otatieto, Espoo, in Finnish). Also, the total number of papers published and accepted for publication in international refereed journals show a new record, 40 items.
Electromagnetic energy around Hertzian dipoles
Hans Gregory Schantz
2001-01-01
This paper considers the behavior of electromagnetic energy around Hertzian dipoles. The method of causal surfaces (surfaces through which there is no net flow of electromagnetic energy) is used to partition and track the energy. A variety of examples, involving both transient and harmonic time dependence, are presented, to illustrate the way in which static and\\/or reactive energy is converted
Transmitting Electromagnetic Energy into Liquids
NASA Technical Reports Server (NTRS)
Johnston, E. J.
1984-01-01
Rough liquid surface enhances coupling. Agitating surface of liquid nitrogen bath with periodic or aperiodic excitation enhances electromagnetic coupling between microwave horn and blackbody temperature standard immersed in liquid. Useful in interfaces between electromagnetic radiation and liquids. Biomedical, radar, and meteorological applications.
The CLAS Forward Electromagnetic Calorimeter
Thomas Jefferson National Accelerator Facility
The CLAS Forward Electromagnetic Calorimeter M. Amarian d , G. Asryan d , K. Beard b , W. Brooks ) 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
Electromagnetism IB Dr Natalia Berloff
Electromagnetism IB Dr Natalia Berloff Summary of Vector Calculus The following results apply to any (suitably differentiable) scalar field (x) and vector fields E(x) and B(x). They all have important applications in electromagnetism. Derivatives of a vector field: div E ·E = Ei xi has one
Torsion as electromagnetism and spin
Nikodem J. Poplawski
2010-07-10
We show that it is possible to formulate the classical Einstein-Maxwell-Dirac theory of spinors interacting with the gravitational and electromagnetic fields as the Einstein-Cartan-Kibble-Sciama theory with the Ricci scalar of the traceless torsion, describing gravity, and the torsion trace acting as the electromagnetic potential.
Numerical calculation of electromagnetic actuators
B. Aldefeld
1979-01-01
Contents The paper describes a numerical method of calculating the magnetic fields, forces, inductances, and the dynamic behaviour of electromagnetic actuators. The solution of the non-linear partial differential equation for the magnetic vector potential is obtained by finite difference techniques using line iteration and acceleration of convergence. Examples of application are given for an electromagnetic print needle actuator.
Gravitational scattering of electromagnetic radiation
NASA Technical Reports Server (NTRS)
Brooker, J. T.; Janis, A. I.
1980-01-01
The scattering of electromagnetic radiation by linearized gravitational fields is studied to second order in a perturbation expansion. The incoming electromagnetic radiation can be of arbitrary multipole structure, and the gravitational fields are also taken to be advanced fields of arbitrary multipole structure. All electromagnetic multipole radiation is found to be scattered by gravitational monopole and time-varying dipole fields. No case has been found, however, in which any electromagnetic multipole radiation is scattered by gravitational fields of quadrupole or higher-order multipole structure. This lack of scattering is established for infinite classes of special cases, and is conjectured to hold in general. The results of the scattering analysis are applied to the case of electromagnetic radiation scattered by a moving mass. It is shown how the mass and velocity may be determined by a knowledge of the incident and scattered radiation.
Nucleon Electromagnetic Form Factors
Marc Vanderhaeghen; Charles Perdrisat; Vina Punjabi
2007-10-01
There has been much activity in the measurement of the elastic electromagnetic proton and neutron form factors in the last decade, and the quality of the data has greatly improved by performing double polarization experiments, in comparison with previous unpolarized data. Here we review the experimental data base in view of the new results for the proton, and neutron, obtained at JLab, MAMI, and MIT-Bates. The rapid evolution of phenomenological models triggered by these high-precision experiments will be discussed, including the recent progress in the determination of the valence quark generalized parton distributions of the nucleon, as well as the steady rate of improvements made in the lattice QCD calculations.
Causal electromagnetic interaction equations
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.
Electromagnetically revolving sphere viscometer
NASA Astrophysics Data System (ADS)
Hosoda, Maiko; Sakai, Keiji
2014-12-01
In this paper, we propose a new method of low viscosity measurement, in which the rolling of a probe sphere on the flat solid bottom of a sample cell is driven remotely and the revolution speed of the probe in a sample liquid gives the viscosity measurements. The principle of this method is based on the electromagnetically spinning technique that we developed, and the method is effective especially for viscosity measurements at levels below 100 mPas with an accuracy higher than 1%. The probe motion is similar to that in the well-known rolling sphere (ball) method. However, our system enables a steady and continuous measurement of viscosity, which is problematic using the conventional method. We also discuss the limits of the measurable viscosity range common to rolling-sphere-type viscometers by considering the accelerating motion of a probe sphere due to gravity, and we demonstrate the performance of our methods.
The Electromagnetic Code Consortium
NASA Astrophysics Data System (ADS)
Faison, Joseph C.
1990-02-01
A decision was made in 1987 to consolidate radar cross section (RCS) code development sponsored by the U.S. armed services and NASA. An RCS code consortium was formed, consisting of a government steering group and members from the industrial/academic community. Since the formation of the consortium, significant progress has been made to advance code development work sponsored by the U.S. government. This paper is intended to make the RCS community aware of the Electromagnetic Code Consortium, so that potential contributors to code development can become involved with its work. It covers the approach taken by the consortium, the acquisition of a government-owned geometry code, validation, language and documentation, the support contractor, a survey of industry codes, and benchmarking.
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.
Computational electronics and electromagnetics
Shang, C. C.
1997-02-01
The Computational Electronics and Electromagnetics thrust area at Lawrence Livermore National Laboratory serves as the focal point for engineering R&D activities for developing computer-based design, analysis, and tools for theory. Key representative applications include design of particle accelerator cells and beamline components; engineering analysis and design of high-power components, photonics, and optoelectronics circuit design; EMI susceptibility analysis; and antenna synthesis. The FY-96 technology-base effort focused code development on (1) accelerator design codes; (2) 3-D massively parallel, object-oriented time-domain EM codes; (3) material models; (4) coupling and application of engineering tools for analysis and design of high-power components; (5) 3-D spectral-domain CEM tools; and (6) enhancement of laser drilling codes. Joint efforts with the Power Conversion Technologies thrust area include development of antenna systems for compact, high-performance radar, in addition to novel, compact Marx generators. 18 refs., 25 figs., 1 tab.
Superconducting electromagnetic thruster
Meng, J.
1993-02-11
An electromagnetic thruster for marine vehicles using a jet of water driven by the interaction of a mutually perpendicular intensified magnetic field and an intensified electric field is disclosed. The intensified magnetic field is produced by superconducting coils cooled by a coolant such as liquid helium. An intensified electric field is produced by passing high amperage current across the seawater jet. These interacting fields produce a Lorentz force perpendicular to mutually perpendicular electric and magnetic field vectors which is used to drive the seawater jet. In some embodiments, the force may also be used to draw water into the jet from the boundary layer flow around the vehicle thereby reducing boundary layer turbulence and associated radiated noise.
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.
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.
NSDL National Science Digital Library
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.
PHYSICS 417. Electromagnetism. Lecturer: Tim Gorringe.
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
Phase-space representation of electromagnetic radiometry
Roman Castaneda
2009-01-01
The phase-space representation of electromagnetic radiometry is founded on the electromagnetic generalized radiance tensors, which allow overcoming the limitations due to the scalar electromagnetic generalized radiances. The fundamental quantities of both scalar generalized radiometry and classical radiometry or photometry become particular cases. The transport of measurable radiometric quantities by the electromagnetic field is described in terms of the propagation of
Electromagnetic metamaterials: Simplicity unlocks complexity
NASA Astrophysics Data System (ADS)
Dal Negro, Luca
2014-12-01
By carefully selecting only two elemental 'building block materials' at the nanoscale, it is possible to digitally design composite electromagnetic media with properties vastly different from their individual constituents and suitable for performing complex optical functions.
Electromagnetic Dissociation and Space Radiation
John W. Norbury; Khin Maung Maung
2006-12-08
Relativistic nucleus-nucleus reactions occur mainly through the Strong or Electromagnetic (EM) interactions. Transport codes often neglect the latter. This work shows the importance of including EM interactions for space radiation applications.
Conical electromagnetic radiation flux concentrator
NASA Technical Reports Server (NTRS)
Miller, E. R.
1972-01-01
Concentrator provides method of concentrating a beam of electromagnetic radiation into a smaller beam, presenting a higher flux density. Smaller beam may be made larger by sending radiation through the device in the reverse direction.
Electromagnetic Showers at High Energy
ERIC Educational Resources Information Center
Loos, J. S.; Dawson, S. L.
1978-01-01
Some of the properties of electromagnetic showers observed in an experimental study are illustrated. Experimental data and results from quantum electrodynamics are discussed. Data and theory are compared using computer simulation. (BB)
Electromagnetic Signals from Bacterial DNA
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.
Black Hole Thermodynamics and Electromagnetism
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.
Time Reversal of Electromagnetic Waves
G. Lerosey; J. de Rosny; A. Tourin; A. Derode; G. Montaldo; M. Fink
2004-01-01
We report the first experimental demonstration of time-reversal focusing with electromagnetic waves. An antenna transmits a 1-mus electromagnetic pulse at a central frequency of 2.45GHz in a high-Q cavity. Another antenna records the strongly reverberated signal. The time-reversed wave is built and transmitted back by the same antenna acting now as a time-reversal mirror. The wave is found to converge
SOLAR NANTENNA ELECTROMAGNETIC COLLECTORS
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.
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.
Electromagnetic Calorimeter for HADES
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.
Electromagnetic Interference on Pacemakers
Erdogan, Okan
2002-01-01
External sources, either within or outside the hospital environment, may interfere with the appropriate function of pacemakers which are being implanted all around the world in current medical practice. The patient and the physician who is responsible for follow-up of the pacing systems may be confronted with some specific problems regarding the various types of electromagnetic interference (EMI). To avoid these unwanted EMI effects one must be aware of this potential problem and need to take some precautions. The effects of EMI on pacemaker function and precautions to overcome some specific problems were discussed in this review article. There are many sources of EMI interacting with pacemakers. Magnetic resonance imaging creates real problem and should be avoided in pacemaker patients. Cellular phones might be responsible for EMI when they were held on the same side with the pacemaker. Otherwise they don't cause any specific type of interaction with pacemakers. Sale security systems are not a problem if one walks through it without lingering in or near it. Patients having unipolar pacemaker systems are prone to develop EMI because of pectoral muscle artifacts during vigorous active physical exercise. PMID:17006562
Megawatt Electromagnetic Plasma Propulsion
NASA Technical Reports Server (NTRS)
Gilland, James; Lapointe, Michael; Mikellides, Pavlos
2003-01-01
The NASA Glenn Research Center program in megawatt level electric propulsion is centered on electromagnetic acceleration of quasi-neutral plasmas. Specific concepts currently being examined are the Magnetoplasmadynamic (MPD) thruster and the Pulsed Inductive Thruster (PIT). In the case of the MPD thruster, a multifaceted approach of experiments, computational modeling, and systems-level models of self field MPD thrusters is underway. The MPD thruster experimental research consists of a 1-10 MWe, 2 ms pulse-forming-network, a vacuum chamber with two 32 diffusion pumps, and voltage, current, mass flow rate, and thrust stand diagnostics. Current focus is on obtaining repeatable thrust measurements of a Princeton Benchmark type self field thruster operating at 0.5-1 gls of argon. Operation with hydrogen is the ultimate goal to realize the increased efficiency anticipated using the lighter gas. Computational modeling is done using the MACH2 MHD code, which can include real gas effects for propellants of interest to MPD operation. The MACH2 code has been benchmarked against other MPD thruster data, and has been used to create a point design for a 3000 second specific impulse (Isp) MPD thruster. This design is awaiting testing in the experimental facility. For the PIT, a computational investigation using MACH2 has been initiated, with experiments awaiting further funding. Although the calculated results have been found to be sensitive to the initial ionization assumptions, recent results have agreed well with experimental data. Finally, a systems level self-field MPD thruster model has been developed that allows for a mission planner or system designer to input Isp and power level into the model equations and obtain values for efficiency, mass flow rate, and input current and voltage. This model emphasizes algebraic simplicity to allow its incorporation into larger trajectory or system optimization codes. The systems level approach will be extended to the pulsed inductive thruster and other electrodeless thrusters at a future date.
Loyka, Sergey
and Radioelectronics (BSUIR) Electromagnetic Compatibility Laboratory 6, P.Brovki st., Minsk 220013, Belarus E Electromagnetic compatibility (EMC) and safety (EMS) of wireless communication networks have been recently
Electromagnetic fields and public health.
Aldrich, T E; Easterly, C E
1987-01-01
A review of the literature is provided for the topic of health-related research and power frequency electromagnetic fields. Minimal evidence for concern is present on the basis of animal and plant research. General observation would accord with the implication that there is no single and manifest health effect as the result of exposure to these fields. There are persistent indications, however, that these fields have biologic activity, and consequently, there may be a deleterious component to their action, possibly in the presence of other factors. Power frequency electromagnetic field exposures are essentially ubiquitous in modern society, and their implications in the larger perspective of public health are unclear at this time. Electromagnetic fields represent a methodological obstacle for epidemiologic studies and a quandary for risk assessment; there is need for more data. PMID:3319560
Un-renormalized classical electromagnetism
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.
Electromagnetic Fields and Public Health
Timothy E. Aldrich; Clay E. Easterly
A review of the literature is provided for the topic of health-related research and power frequency electromagnetic fields. Minimal evidence for concern is present on the basis of animal and plant research. General observation would accord with the implication that there is no single and manifest health effect as the result of exposure to these fields. There are persistent indications, however, that these fields have biologic activity, and consequently, there may be a deleterious component to their action, possibly in the presence of other factors. Power frequency electromagnetic field exposures are essentially ubiquitous in modern society, and their implications in the larger perspective of public health are unclear at this time. Electromagnetic fields represent a methodological obstacle for epidemiologic studies and a quandary for risk assessment; there is need for more data.
Dipole-induced electromagnetic transparency.
Puthumpally-Joseph, Raiju; Sukharev, Maxim; Atabek, Osman; Charron, Eric
2014-10-17
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 us to achieve narrow transmission windows in, otherwise, completely opaque media. We analyze in detail 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. PMID:25361258
Biological effects of electromagnetic fields.
Macr, M. A.; Di Luzio, Sr.; Di Luzio, S.
2002-01-01
Nowadays, concerns about hazards from electromagnetic fields represent an alarming source for human lives in technologically developed countries. We are surrounded by electromagnetic fields everywhere we spend our working hours, rest or recreational activities. The aim of this review is to summarize the biological effects due to these fields arising from power and transmission lines, electrical cable splices, electronic devices inside our homes and work-places, distribution networks and associated devices such as cellular telephones and wireless communication tower, etc. Special care has been reserved to study the biological effects of electromagnetic fields on cell lines of the mammalian immune system about which our research group has been working for several years. PMID:12590871
Dipole-Induced Electromagnetic Transparency
NASA Astrophysics Data System (ADS)
Puthumpally-Joseph, Raiju; Sukharev, Maxim; Atabek, Osman; Charron, Eric
2014-10-01
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 us to achieve narrow transmission windows in, otherwise, completely opaque media. We analyze in detail 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.
Holographic Estimate of Electromagnetic Mass
Deog Ki Hong
2015-01-26
Using the gauge/gravity duality, we calculate the electromagnetic contributions to hadron masses, where mass generates dynamically by strong QCD interactions. Based on the Sakai-Sugimoto model of holographic QCD we find that the electromagnetic mass of proton is 0.48 MeV larger than that of neutron, which is in agreement with recent lattice results. Similarly for pions we obtain $m_{\\pi^{\\pm}}-m_{\\pi^0}$=3.6 ~ 7.2 MeV, close to the experimental value, taking a ultraviolet cutoff $\\Lambda\\simeq 4M_{\\rm KK}$.
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.
Electromagnetic radiation by gravitating bodies
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.
Electromagnetic decay of {lambda}(1520)
Myhrer, F. [Department of Physics and Astronomy, University of South Carolina, Columbia, South Carolina 29208 (United States)
2006-12-15
The electromagnetic decay processes of excited hyperon states are a very sensitive probe of the structure of hyperons. We will argue that the recent measurements of electromagnetic decay rates indicate that the wave functions of the hyperon ground states should contain sizable components of excited quark states (configuration mixing). Flavor-SU(3) is a broken symmetry and it appears that the hyperon wave functions should preferably be written in a uds-basis, where only the light u and d-quarks are symmetrized, and not in the usual SU(6)-basis.
I. What is electromagnetic radiation and the electromagnetic spectrum?
Sitko, Michael L.
, they are all the same kind of "stuff." They all travel through space and have similar electrical and magnetic effects on matter. This "stuff" is called electromagnetic radiation, because it travels (radiates) and has. Human Eye Response { increasing increasing decreasing decreasing decreasing increasing ENERGY frequency
Visible Light and the Electromagnetic Spectrum
NSDL National Science Digital Library
Integrated Teaching and Learning Program,
During this lesson, the electromagnetic spectrum is explained and students learn that visible light makes up only a portion of this wide spectrum. Students also learn that engineers use electromagnetic waves for many different applications.
Electromagnetic formation flight dipole solution planning
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 ...
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.
Electromagnetic effects on geodesic acoustic modes
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 So Paulo, So 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.
Why Study Electromagnetics: The First Unit in an Undergraduate Electromagnetics Course
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
STIMULATED ELECTROMAGNETIC EMISSIONS BY HIGH-FREQUENCY ELECTROMAGNETIC PUMPING OF THE
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
Donuts make diffractionless electromagnetic waves
Ya-Lun Tsai; Jyun-Hong Lu; Hua-Kung Chiu; Ching-Yi Chen; Chii-Chang Chen; Jenq-Yang Chang
This work finds that a diffractionless beam can be obtained using periodically arranged donut (torus) waveguides. The Bessel-like field distribution is observed at the output of the waveguide. The structure may be built for electromagnetic waves of any wavelength, including radiowaves, microwaves, infrared light, visible light and UV light. The diameter of the diffractionless beam is of the order of
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
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.
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 Earths 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.
Technology-based electromagnetic education
Magdy F. Iskander
2002-01-01
In this paper, we briefly review the various roles of technology in stimulating interest and deepening understanding of abstract and highly mathematical subjects such as electromagnetics (EM). The general advantages of using technology in offering Web-based courses and professional training are described and examples of the ongoing activities in this area are summarized. Focus, however, is placed on the development
Interpreting Electromagnetic Reflections In Glaciology
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
Carbon onions for electromagnetic applications
S. Maksimenko; P. Kuzhir; G. Slepyan; V. Kuznetsov; O. Shenderova; A. Okotrub; L. G. Bulusheva; J. Macutkevic; P. Lambin
2010-01-01
Electromagnetic (EM) absorption properties of a novel nanocarbon material - onion-like carbon (OLC) produced by annealing of detonation nanodiamonds (ND) in vacuum - have been studied in low-frequency, microwave and THz frequency ranges. It was proved experimentally that OLC EM absorption capacity can be optimized by varying the nanocarbon cluster size and ND annealing temperature so that effective EM coatings
Electromagnetic electron temperature anisotropy instabilities
NASA Technical Reports Server (NTRS)
Gary, S. P.; Madland, C. D.
1985-01-01
This paper considers electromagnetic Vlasov instabilities driven by electron temperature anisotropies in a homogeneous, nonrelativistic magnetized plasma. Numerical solutions of the full linear dispersion equation for bi-Maxwellian distribution functions and instabilities propagating parallel to the magnetic field are presented. Parametric dependences of the maximum growth rates of the electron fire hose and whistler anisotropy instabilities are given.
Electromagnetic electron temperature anisotropy instabilities
NASA Astrophysics Data System (ADS)
Gary, S. P.; Madland, C. D.
1985-08-01
This paper considers electromagnetic Vlasov instabilities driven by electron temperature anisotropies in a homogeneous, nonrelativistic magnetized plasma. Numerical solutions of the full linear dispersion equation for bi-Maxwellian distribution functions and instabilities propagating parallel to the magnetic field are presented. Parametric dependences of the maximum growth rates of the electron fire hose and whistler anisotropy instabilities are given.
Transient electromagnetic interference in substations
C. M. Wiggins; D. E. Thomas; F. S. Nickel; T. M. Salas; S. E. Wright
1994-01-01
Electromagnetic interference levels on sensitive electronic equipment are quantified experimentally and theoretically in air and gas insulated substations of different voltages. Measurement techniques for recording interference voltages and currents and electric and magnetic fields are reviewed and actual interference data are summarized. Conducted and radiated interference coupling mechanisms and levels in substation control wiring are described using both measurement results
Electromagnetic scattering from dielectric bodies
Tapan K. Sarkar; Ercument Arvas; Saila Ponnapalli
1989-01-01
Far-field results obtained by two different methods are compared for the problem of electromagnetic scattering from dielectric objects. The two methods are the surface integral formulation, utilizing equivalent electric and magnetic surface currents, and the volume formulation, utilizing the equivalent electric polarization current. Triangular patches are used in the surface formulation and cubical cells are used in the volume formulation.
Electromagnetic calorimeter for Belle II
NASA Astrophysics Data System (ADS)
Belle-ECL; Aulchenko, V.; Bobrov, A.; Bondar, A.; Cheon, B. G.; Eidelman, S.; Epifanov, D.; Garmash, Yu; Goh, Y. M.; Kim, S. H.; Krokovny, P.; Kuzmin, A.; Lee, I. S.; Matvienko, D.; Miyabayashi, K.; Nakamura, I.; Shebalin, V.; Shwartz, B.; Unno, Y.; Usov, Yu; Vinokurova, A.; Vorobjev, V.; Zhilich, V.; Zhulanov, V.
2015-02-01
The electromagnetic calorimeter of the BELLE II detector for experiments at Super B-factory SuperKEKB is briefly described. The project of the calorimeter upgrade to meet severe background conditions expected at the upgraded KEK B factory is presented.
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
Electromagnetic Design With Transformation Optics
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
611: Electromagnetic Theory Problem Sheet 5
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
Course Outline Physics 433: Electromagnetism II
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
611: Electromagnetic Theory Problem Sheet 5
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
611: Electromagnetic Theory Problem Sheet 5
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
Electromagnetic Formation Flight of Satellite Arrays
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
611: Electromagnetic Theory Problem Sheet 6
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
Electromagnetics from Simulation to Optimal Design
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
Electromagnetic Interrogation of Dielectric Materials 1
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
Emission of Electromagnetic Radiation Upon Electric Stimulation
Karczmarek, Joanna
Emission of Electromagnetic Radiation Upon Electric Stimulation of Preserved Cucumis sativus of ElectromagneticEmission of Electromagnetic Radiation Upon ElectricRadiation Upon Electric Stimulation of PreservedStimulation-Pronged Electrical Cord · Electrical Tape · 2 Pins · Variac · Spectroscopes #12;How it all goes together
ABSORBING BOUNDARY CONDITIONS FOR ELECTROMAGNETIC WAVE PROPAGATION
ABSORBING BOUNDARY CONDITIONS FOR ELECTROMAGNETIC WAVE PROPAGATION Xiaobing Feng y Abstract of the electromagnetic fields indi vidually. This boundary condition allows any wave motion generated within the domain, and the electromagnetic wave scattering related to antennas. Because of the limitations of both speed and memory
Electromagnetic Radiation REFERENCE: Remote Sensing of
Gilbes, Fernando
1 CHAPTER 2: Electromagnetic Radiation Principles REFERENCE: Remote Sensing of the Environment John Radiation Models To understand how electromagnetic radiation is created, how it propagates through space: · the wave model · the particle model Wave Model of Electromagnetic Radiation In the 1860s, James Clerk
JOSEPHSON DETECTORS OF MILLIMETER ELECTROMAGNETIC RADIATION
Paris-Sud XI, Université de
293 JOSEPHSON DETECTORS OF MILLIMETER ELECTROMAGNETIC RADIATION V. A. KULIKOV, N. N. KURDJUMOV, G. 2014 The possibility of construction of high sensitive detectors of electromagnetic radiation is devoted to detectors of electromagnetic radiation in the upper millimeter range, designed for use
Electromagnetic Corrections in Staggered Chiral Perturbation Theory
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
Acousto-electromagnetic Tomography Habib Ammari
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
Physics 4: Introductory Physics Electromagnetism and Light
Fygenson, Deborah Kuchnir
loop; electromagnets vs. permanent magnets; Ampere's Law and "circulation"; magnetic materials 28Physics 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
A technology that squeezes electromagnetic waves
Atwater, Harry
A technology that squeezes electromagnetic waves into minuscule structures may yield a new and manipulate visible light and other electromagnetic waves--could someday replace electronic circuits in micro plasmons with the same frequency as the outside electromagnetic waves but with a much shorter wavelength
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.
Strong permanent magnet-assisted electromagnetic undulator
Halbach, Klaus (Berkeley, CA)
1988-01-01
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.
Cross-spectral purity of electromagnetic fields.
Hassinen, Timo; Tervo, Jani; Friberg, Ari T
2009-12-15
We extend Mandel's scalar-wave concept of cross-spectral purity to electromagnetic fields. We show that in the electromagnetic case, assumptions similar to the scalar cross-spectral purity lead to a reduction formula, analogous with the one introduced by Mandel. We also derive a condition that shows that the absolute value of the normalized zeroth two-point Stokes parameter of two cross-spectrally pure electromagnetic fields is the same for every frequency component of the field. In analogy with the scalar theory we further introduce a measure of the cross-spectral purity of two electromagnetic fields, namely, the degree of electromagnetic cross-spectral purity. PMID:20016640
Some Wave Equations for Electromagnetism and Gravitation
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.
Electromagnetic shielding in quantum metrology
NASA Astrophysics Data System (ADS)
Jin, Yao; Yu, Hongwei
2015-02-01
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.
Falling Magnets and Electromagnetic Braking
NASA Astrophysics Data System (ADS)
Culbreath, Christopher; Palffy-Muhoray, Peter
2009-03-01
The slow fall of a rare earth magnet through a copper pipe is a striking example of electromagnetic braking; this remarkable phenomenon has been the subject of a number of scientific paper s [1, 2]. In a pipe having radius R and wall thickness D, the terminal velocity of the falling magnet is proportional to (R?4)/D. It is interesting to ask what happens in the limit as D becomes very large. We report our experimental observations and theoretical predictions of the dependence of the terminal velocity on pipe radius R for large D. [1] Y. Levin, F.L. da Silveira, and F.B. Rizzato, ``Electromagnetic braking: A simple quantitative model''. American Journal of Physics, 74(9): p. 815-817 (2006). [2] J.A. Pelesko, M. Cesky, and S. Huertas, Lenz's law and dimensional analysis. American Journal of Physics, 3(1): p. 37-39. 2005.
The hidden geometry of electromagnetism
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.
The hidden geometry of electromagnetism
Yaron Hadad; Eliahu Cohen; Ido Kaminer; Avshalom C. Elitzur
2015-03-03
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.
Genetic algorithms in engineering electromagnetics
J. Michael Johnson; V. Rahmat-Samii
1997-01-01
This paper presents a tutorial and overview of genetic algorithms for electromagnetic optimization. Genetic-algorithm (GA) optimizers are robust, stochastic search methods modeled on the concepts of natural selection and evolution. The relationship between traditional optimization techniques and the GA is discussed. Step-by-step implementation aspects of the GA are detailed, through an example with the objective of providing useful guidelines for
Electromagnetic radiation produces frame dragging
NASA Astrophysics Data System (ADS)
Herrera, L.; Barreto, W.
2012-09-01
It is shown that for a generic electrovacuum spacetime, electromagnetic radiation produces vorticity of worldlines of observers in a Bondi-Sachs frame. Such an effect (and the ensuing gyroscope precession with respect to the lattice) which is a reminiscence of generation of vorticity by gravitational radiation, may be linked to the nonvanishing of components of the Poynting and the super-Poynting vectors on the planes othogonal to the vorticity vector. The possible observational relevance of such an effect is commented upon.
Dark Energy, Gravitation and Electromagnetism
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.
Localized transmission of electromagnetic energy
Richard W. Ziolkowski
1989-01-01
Novel electromagnetic directed-energy pulse train (EDEPT) solutions of Maxwell's equations have been obtained. One particular solution, the modified-power-spectrum (MPS) pulse, will be described in detail. EDEPT's such as the MPS pulses, can be tailored to give localized energy transmission along a specified direction in space that is significantly improved over conventional diffraction-limited beams. Moreover, they represent fields that recover their
Pulsed power for electromagnetic launching
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.
Electromagnetic Calorimeter for HADES Experiment
NASA Astrophysics Data System (ADS)
Rodrguez-Ramos, P.; Chlad, L.; Epple, E.; Fabbietti, L.; Galatyuk, T.; Golubeva, M.; Guber, F.; Hlav?, S.; Ivashkin, A.; Kajetanowic, M.; Kardan, B.; Koenig, W.; Korcyl, G.; Kugler, A.; Lapidus, K.; Linev, S.; Lisowski, E.; Neiser, A.; Ott, O.; Otte, O.; Pethukov, O.; Pietraszko, J.; Reshetin, A.; Rost, A.; Salabura, P.; Sobolev, Y. G.; Svoboda, O.; Thomas, A.; Tlusty, P.; Traxler, M.
2014-11-01
Electromagnetic calorimeter (ECAL) is being developed to complement dilepton spectrometer HADES. 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 AGeV on the beam of future accelerator SIS100@FAIR. We will report results of the last beam test with quasi-monoenergetic photons carried out in MAMI facility at Johannes Gutenberg Universitt Mainz.
Laminated electromagnetic pump stator core
Fanning, Alan W. (San Jose, CA)
1995-01-01
A stator core for an electromagnetic pump includes a plurality of circumferentially abutting tapered laminations extending radially outwardly from a centerline axis to collectively define a radially inner bore and a radially outer circumference. Each of the laminations includes radially inner and outer edges and has a thickness increasing from the inner edge toward the outer edge to provide a substantially continuous path adjacent the circumference.
Laminated electromagnetic pump stator core
Fanning, A.W.
1995-08-08
A stator core for an electromagnetic pump includes a plurality of circumferentially abutting tapered laminations extending radially outwardly from a centerline axis to collectively define a radially inner bore and a radially outer circumference. Each of the laminations includes radially inner and outer edges and has a thickness increasing from the inner edge toward the outer edge to provide a substantially continuous path adjacent the circumference. This pump is used in nuclear fission reactors. 19 figs.
Electromagnetic brake/clutch device
NASA Astrophysics Data System (ADS)
Vranish, John M.
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.
Electromagnetism on anisotropic fractal media
NASA Astrophysics Data System (ADS)
Ostoja-Starzewski, Martin
2013-04-01
Basic equations of electromagnetic fields in anisotropic fractal media are obtained using a dimensional regularization approach. First, a formulation based on product measures is shown to satisfy the four basic identities of the 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 Ampre 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, so as 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 in three different directions and reduce to conventional forms for continuous media with Euclidean geometries upon setting these each of dimensions equal to unity.
Electromagnetic Effects in SDF Explosions
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.
Strong permanent magnet-assisted electromagnetic undulator
Halbach, K.
1988-08-02
This patent describes an undulator wherein electromagnet poles are located along opposite sides of a particle beam axis normal to the 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, the improvement which comprises reducing the saturation of the electromagnet poles by the use of permanent magnets spaced in between adjacent electromagnetic poles on each side of the axis of the particle beam in an orientation wherein the north and south poles of the permanent magnets are parallel to the particle beam axis and normal to the magnetic axes of the electromagnetic poles to reduce the saturation of the electromagnets to thereby permit the increasing of the field strength of the electromagnets beyond normal saturation levels.
Quantum electromagnetic waves in nonstationary linear media
NASA Astrophysics Data System (ADS)
Pedrosa, I. A.
2011-03-01
We present a quantum description of electromagnetic waves propagating through time-dependent homogeneous nondispersive conducting and nonconducting linear media without charge sources. Based on the Coulomb gauge and the quantum invariant method, we find the exact wave functions for this problem. In addition, we construct coherent and squeezed states for the quantized electromagnetic waves and evaluate the quantum fluctuations in coordinate and momentum space as well as the uncertainty product for each mode of the electromagnetic field.
Electromagnetic interactions at RHIC and LHC
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.
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
Thin sheet casting with electromagnetic pressurization
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.
Electromagnetic Imaging Methods for Nondestructive Evaluation Applications
Deng, Yiming; Liu, Xin
2011-01-01
Electromagnetic nondestructive tests are important and widely used within the field of nondestructive evaluation (NDE). The recent advances in sensing technology, hardware and software development dedicated to imaging and image processing, and material sciences have greatly expanded the application fields, sophisticated the systems design and made the potential of electromagnetic NDE imaging seemingly unlimited. This review provides a comprehensive summary of research works on electromagnetic imaging methods for NDE applications, followed by the summary and discussions on future directions. PMID:22247693
Scalar invariants in gravitational and electromagnetic fields
Zihua Weng
2009-06-22
The paper discusses some scalar invariants in the gravitational field and electromagnetic field by means of the characteristics of the quaternions. When we emphasize some definitions of quaternion physical quantities, the speed of light, mass density, energy density, power density, charge density, and spin magnetic moment density etc. will remain the same respectively in the gravitational and electromagnetic fields under the coordinate transformation. The results explain why there are some relationships among different invariants in the gravitational and electromagnetic fields.
An electromagnetic analog of gravitational wave memory
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.
Electromagnetic wave scattering by Schwarzschild black holes
Lus 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.
Detection of electromagnetic waves using MEMS antennas
Lavrik, Nickolay V [ORNL] [ORNL; Tobin, [Oak Ridge National Laboratory (ORNL)] [Oak Ridge National Laboratory (ORNL); Bowland, Landon T [ORNL] [ORNL
2011-01-01
We describe the design, fabrication and characterization of simple micromechanical structures that are capable of sensing static electric time varying electromagnetic fields. Time varying electric field sensing is usually achieved using an electromagnetic antenna and a receiver. However, these antenna-based approaches do not exhibit high sensitivity over a broad frequency (or wavelength) range. An important aspect of the present work is that, in contrast to traditional antennas, the dimensions of these micromechanical oscillators can be much smaller than the wavelength of the electromagnetic wave. We characterized the fabricated micromechanical oscillators by measuring their responses to time varying electric and electromagnetic fields.
22.105 Electromagnetic Interactions, Fall 1998
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 ...
6.630 Electromagnetic Theory, Fall 2002
Kong, Jin Au, 1942-
6.630 is an introductory subject on electromagnetics, emphasizing fundamental concepts and applications of Maxwell equations. Topics covered include: polarization, dipole antennas, wireless communications, forces and energy, ...
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.
T. T. Natarajan; Nagy El-Kaddah
2004-01-01
This paper describes a fixed-grid methodology for the numerical simulation of electromagnetically driven flow in three-dimensional inductively stirred systems. It is based on a hybrid differentialintegral formulation of the electromagnetic field to limit the finite difference\\/element solution of the electromagnetic field problem to the fluid flow domain. The electromagnetic field in the system was described using current vector potential (T)
Logic for electromagnetic field patterns
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.
Electromagnetic effects on transportation systems
Morris, M.E.; Dinallo, M.A.
1996-05-01
Electronic and electrical system protection design can be used to eliminate deleterious effects from lightning, electromagnetic interference, and electrostatic discharges. Evaluation of conventional lightning protection systems using advanced computational modeling in conjunction with rocket-triggered lightning tests suggests that currently used lightning protection system design rules are inadequate and that significant improvements in best practices used for electronic and electrical system protection designs are possible. A case study of lightning induced upset and failure of a railway signal and control system is sketched.
Electromagnetic properties of massive neutrinos
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.
Extremely low frequency electromagnetic fields
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.
Electromagnetic weak turbulence theory revisited
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.
Quantum modulation against electromagnetic interference
Juan Carlos Garcia-Escartin
2014-11-26
Periodic signals in electrical and electronic equipment can cause interference in nearby devices. Randomized modulation of those signals spreads their energy through the frequency spectrum and can help to mitigate electromagnetic interference problems. The inherently random nature of quantum phenomena makes them a good control signal. I present a quantum modulation method based on the random statistics of quantum light. The paper describes pulse width modulation schemes where a Poissonian light source acts as a random control that spreads the energy of the potential interfering signals. I give an example application for switching-mode power supplies and comment the further possibilities of the method.
JAN ABRAHAM FERREIRA; J. DAAN VAN WYK
2001-01-01
Historically, it came about that the analysis and design of the power electronic converter center around currents and voltages in the circuits. During the last decade, the electromagnetic character of power electronic converters became more important due to the noise that the switches generate, and electromagnetic interference (EMI) and electromagnetic compatibility (EMC) standards have been put in place to control
4/9/2004 1 Name of the Presentation Fundamental Properties of Electromagnetic RadiationFundamental Properties of Electromagnetic Radiation Energy is the ability to do work. In the process of doing work by electromagnetic radiation is of primary interest to remote sensing because it is the only form of energy transfer
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.
Electromagnetic probes of the QGP
E. L. Bratkovskaya; O. Linnyk; W. Cassing
2014-09-15
We investigate the properties of the QCD matter across the deconfinement phase transition in the scope of the parton-hadron string dynamics (PHSD) transport approach. We present here in particular the results on the electromagnetic radiation, i.e. photon and dilepton production, in relativistic heavy-ion collisions. By comparing our calculations for the heavy-ion collisions to the available data, we determine the relative importance of the various production sources and address the possible origin of the observed strong elliptic flow $v_2$ of direct photons. We argue that the different centrality dependence of the hadronic and partonic sources for direct photon production in nucleus-nucleus collisions can be employed to shed some more light on the origin of the photon $v_2$ "puzzle". While the dilepton spectra at low invariant mass show in-medium effects like an enhancement from multiple baryonic resonance formation or a collisional broadening of the vector meson spectral functions, the dilepton yield at high invariant masses (above 1.1 GeV) is dominated by QGP contributions for central heavy-ion collisions at ultra-relativistic energies. This allows to have an independent view on the parton dynamics via their electromagnetic massive radiation.
Covariant jump conditions in electromagnetism
Yakov Itin
2014-03-30
A generally covariant four-dimensional representation of Maxwell's electrodynamics in a generic material medium can be achieved straightforwardly in the metric-free formulation of electromagnetism. In this setup, the electromagnetic phenomena described by two tensor fields, which satisfy Maxwell's equations. A generic tensorial constitutive relation between these fields is an independent ingredient of the theory. By use of different constitutive relations (local and non-local, linear and non-linear, etc.), a wide area of applications can be covered. In the current paper, we present the jump conditions for the fields and for the energy-momentum tensor on an arbitrarily moving surface between two media. From the differential and integral Maxwell equations, we derive the covariant boundary conditions, which are independent of any metric and connection. These conditions include the covariantly defined surface current and are applicable to an arbitrarily moving smooth curved boundary surface. As an application of the presented jump formulas, we derive a Lorentzian type metric as a condition for existence the wave front in isotropic media. This result holds for the ordinary materials as well as for the metamaterials with the negative material constants.
Millimeter Waves: Acoustic and Electromagnetic
Ziskin, Marvin C.
2012-01-01
This article is the presentation I gave at the D'Arsonval Award Ceremony on June 14, 2011 at the Bioelectromagnetics Society Annual Meeting in Halifax, Nova Scotia. It summarizes my research activities in acoustic and electromagnetic millimeter waves over the past 47 years. My earliest research involved acoustic millimeter waves, with a special interest in diagnostic ultrasound imaging and its safety. For the last 21 years my research expanded to include electromagnetic millimeter waves, with a special interest in the mechanisms underlying millimeter wave therapy. Millimeter wave therapy has been widely used in the former Soviet Union with great reported success for many diseases, but is virtually unknown to Western physicians. I and the very capable members of my laboratory were able to demonstrate that the local exposure of skin to low intensity millimeter waves caused the release of endogenous opioids, and the transport of these agents by blood flow to all parts of the body resulted in pain relief and other beneficial effects. PMID:22926874
Electromagnetic scattering from buried objects
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.
PARAXIAL COUPLING OF ELECTROMAGNETIC WAVES IN RANDOM MEDIA
Garnier, Josselin
PARAXIAL COUPLING OF ELECTROMAGNETIC WAVES IN RANDOM MEDIA JOSSELIN GARNIER AND KNUT SLNA Abstract. We consider the propagation of temporally pulsed electromagnetic waves in a three- dimensional random, and imaging. Key words. Electromagnetic waves, parabolic approximation, enhanced backscattering, ran- dom
Ben Zion Steinberg Electromagnetic Waves -Propagation and Scattering
Steinberg, Ben
Ben Zion Steinberg Electromagnetic Waves - Propagation and Scattering Nano photonics Devices Antennas Miniaturization and Isolation Electromagnetic Waves - Propagation and Scattering-plasmonics Interlay of two-type rotation: Electromagnetic (e.g. Faraday rotation) Geometric (e.g. chirality
ANDERSON LOCALIZATION OF ELECTROMAGNETIC WAVES IN CONFINED DISORDERED DIELECTRIC MEDIA
Rusek, Marian
ANDERSON LOCALIZATION OF ELECTROMAGNETIC WAVES IN CONFINED DISORDERED DIELECTRIC MEDIA MARIAN RUSEK, Poland 1. Introduction Scattering of electromagnetic waves from varoius kind of obstacles is rich experimental demonstration that Anderson localization of electromagnetic waves is possible in three
Electromagnetic Visibility and Invisibility Massachusetts Institute of Technology
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
AN ELECTROMAGNETIC INVERSE PROBLEM IN CHIRAL STEPHEN R. MCDOWALL
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
Electromagnetic formulation of global gyrokinetic particle simulation in toroidal geometry
Lin, Zhihong
Electromagnetic formulation of global gyrokinetic particle simulation in toroidal geometry I. Holod online 9 December 2009 The fluid-kinetic hybrid electron model for global electromagnetic gyrokinetic the capabilities to describe low frequency processes in electromagnetic turbulence with electron dynamics
Electromagnetic signature of human cortical dynamics during wakefulness and sleep
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
Electromagnets 1: Turn on the Power. Science in a Box.
ERIC Educational Resources Information Center
Whitman, Betsy Blizard
1992-01-01
The article presents inexpensive activities to teach elementary school students about electromagnets. Students learn to make an electromagnet with a battery, nail, and wire, then different activities help them explore the difference between permanent magnets and electromagnets. (SM)
DETECTING UNEXPLODED ORDNANCE WITH TIME DOMAIN ELECTROMAGNETIC Leonard Rodriguez Pasion
Oldenburg, Douglas W.
DETECTING UNEXPLODED ORDNANCE WITH TIME DOMAIN ELECTROMAGNETIC INDUCTION By Leonard Rodriguez Assumption '(')'(')'('(')'('(')'('(')'('(')'('(')'(')'('(')'('(')'(' 10 2.2 Electromagnetic Induction;Abstract In this thesis I assume that the Time Domain Electromagnetic (TEM) response of a buried axisymmet
Electromagnetic Induction Rediscovered Using Original Texts.
ERIC Educational Resources Information Center
Barth, Michael
2000-01-01
Describes a teaching unit on electromagnetic induction using historic texts. Uses some of Faraday's diary entries from 1831 to introduce the phenomenon of electromagnetic induction and teach about the properties of electricity, of taking conclusions from experiment, and scientific methodology. (ASK)
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,
Correlation Electromagnetic Analysis for Cryptographic Device
Guo Liang Ding; Jie Chu; Liang Yuan; Qiang Zhao
2009-01-01
The article analyzes the CMOS logical gate's electric current characteristic under the active status, establishes the electromagnetic information leakage hamming distance model in registers level. Aimed at the data encryption standard (DES) cryptographic system realized by the P89C668 microcomputer, Correlation Electromagnetic Analysis (CEMA) algorithm was described, the choosing of attack point D and the computational method were analyzed, an attack
Electromagnetic corrections to light hadron masses
A. Portelli; S. Drr; Z. Fodor; J. Frison; C. Hoelbling; S. D. Katz; S. Krieg; T. Kurth; L. Lellouch; T. Lippert; K. K. Szab; 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.
Wavelets and electromagnetic power system transients
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
Electromagnetic Modelling of Superconducting Sensor Designs
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...
Passive vibration control via electromagnetic shunt damping
Sam Behrens; Andrew J. Fleming; S. O. Reza Moheimani
2005-01-01
This work will present a new type of passive vibration control technique based on the concept of electromagnetic shunt damping. The proposed technique is similar to piezoelectric shunt damping, as an appropriately designed impedance is shunted across the terminals of the transducer. Theoretical and experimental results are presented for a simple electromagnetic mass spring damper system.
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
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
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)
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 electromagnetsone 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.
The ATLAS Liquid Argon Electromagnetic Calorimeter 1
Boyer, Edmond
The ATLAS Liquid Argon Electromagnetic Calorimeter 1 Pascal Pralavorio (for the ATLAS Liquid Argon operation on the LHC in 2005. The collab- oration has chosen a Liquid Argon electromagnetic calorimeter calorimeter is a sampling calorimeter where absorbers are made of lead and liquid argon is the ionising medium
Narrow field electromagnetic sensor system and method
McEwan, T.E.
1996-11-19
A narrow field electromagnetic sensor system and method of sensing a characteristic of an object provide the capability to realize a characteristic of an object such as density, thickness, or presence, for any desired coordinate position on the object. One application is imaging. The sensor can also be used as an obstruction detector or an electronic trip wire with a narrow field without the disadvantages of impaired performance when exposed to dirt, snow, rain, or sunlight. The sensor employs a transmitter for transmitting a sequence of electromagnetic signals in response to a transmit timing signal, a receiver for sampling only the initial direct RF path of the electromagnetic signal while excluding all other electromagnetic signals in response to a receive timing signal, and a signal processor for processing the sampled direct RF path electromagnetic signal and providing an indication of the characteristic of an object. Usually, the electromagnetic signal is a short RF burst and the obstruction must provide a substantially complete eclipse of the direct RF path. By employing time-of-flight techniques, a timing circuit controls the receiver to sample only the initial direct RF path of the electromagnetic signal while not sampling indirect path electromagnetic signals. The sensor system also incorporates circuitry for ultra-wideband spread spectrum operation that reduces interference to and from other RF services while allowing co-location of multiple electronic sensors without the need for frequency assignments. 12 figs.
Narrow field electromagnetic sensor system and method
McEwan, Thomas E. (Livermore, CA)
1996-01-01
A narrow field electromagnetic sensor system and method of sensing a characteristic of an object provide the capability to realize a characteristic of an object such as density, thickness, or presence, for any desired coordinate position on the object. One application is imaging. The sensor can also be used as an obstruction detector or an electronic trip wire with a narrow field without the disadvantages of impaired performance when exposed to dirt, snow, rain, or sunlight. The sensor employs a transmitter for transmitting a sequence of electromagnetic signals in response to a transmit timing signal, a receiver for sampling only the initial direct RF path of the electromagnetic signal while excluding all other electromagnetic signals in response to a receive timing signal, and a signal processor for processing the sampled direct RF path electromagnetic signal and providing an indication of the characteristic of an object. Usually, the electromagnetic signal is a short RF burst and the obstruction must provide a substantially complete eclipse of the direct RF path. By employing time-of-flight techniques, a timing circuit controls the receiver to sample only the initial direct RF path of the electromagnetic signal while not sampling indirect path electromagnetic signals. The sensor system also incorporates circuitry for ultra-wideband spread spectrum operation that reduces interference to and from other RF services while allowing co-location of multiple electronic sensors without the need for frequency assignments.
Forward electromagnetic scattering models for sea ice
K. M. Golden; M. Cheney; Kung-Hau Ding; A. K. Fung; Thomas C. Grenfell; D. Isaacson; Jin Au Kong; S. V. Nghiem; J. Sylvester; P. Winebrenner
1998-01-01
Recent advances in forward modeling of the electromagnetic scattering properties of sea ice are presented. In particular, the principal results include the following: (1) approximate calculations of electromagnetic scattering from multilayer random media with rough interfaces, based on the distorted Born approximation and radiative transfer (RT) theory; (2) comprehensive theory of the effective complex permittivity of sea ice based on
Electromagnetic bonding of plastics to aluminum
NASA Technical Reports Server (NTRS)
Sheppard, A. T.; Silbert, L.
1980-01-01
Electromagnetic curing is used to bond strain gage to aluminum tensile bar. Electromagnetic energy heats only plastic/metal interface by means of skin effect, preventing degradation of heat-treated aluminum. Process can be easily applied to other metals joined by high-temperature-curing plastic adhesives.
LHCb electromagnetic calorimeter calibration and performance
LHCb electromagnetic calorimeter calibration and performance Savrina Daria ITEP, Moscow SINP MSU system Main requierements: Energy resolution E/E = 10%/E+1%; Fast responce ~25ns; Stable operation under Electromagnetic calorimeter (ECAL) Geometrical acceptance of 300 mrad 250 mrad Shashlik sampling technology
Electromagnetic energy in a dispersive metamaterial
A. D. Boardman; K. Marinov
2006-01-01
An expression for the electromagnetic field energy density in a dispersive lossy left-handed metamaterial, consisting of an array of split-ring resonators and an array of wires, is derived. An electromagnetic field with general time dependence is considered. The outcome is compared with previously published results. In the absence of losses, agreement with the general result for the energy density in
Space-time Curvature of Classical Electromagnetism
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.
Electromagnetic unidirectionality in magnetic photonic crystals
A. Figotin; I. Vitebskiy
2003-01-01
We study the effect of electromagnetic unidirectionality, which can occur in magnetic photonic crystals under certain conditions. A unidirectional periodic medium, being perfectly transparent for an electromagnetic wave of certain frequency, ``freezes'' the radiation of the same frequency propagating in the opposite direction. One of the most remarkable manifestations of the unidirectionality is that while the incident radiation can enter
Integration of basic electromagnetism and engineering technology
S. Bentz
1995-01-01
The theory of electromagnetism is taught as a part of most contemporary electrical engineering curricula. Usually a basic course is intended to cover all the fundamental electromagnetic theory which is needed in later engineering courses. However it is often found that students fail to understand and retain much of the course material, which in turn makes their subsequent studies more
PHYSICS 416. Electromagnetism. Lecturer: Tim Gorringe.
MacAdam, Keith
PHYSICS 416. Electromagnetism. Lecturer: Tim Gorringe. Office: CP 273. Phone: 257-8740. Textbook of two basic field properties - flux and circulation. We will develop physical pictures of these field sophisticated electromagnetic problem solvers. Div, grad and curl, Gauss's theorem and Stokes theorem are just
Pseudoclassical neutrino in the external electromagnetic field
Grigorian, G V
1995-01-01
The problem of the passage of the neutral massless particle with anomalous magnetic moment through the external electromagnetic field is considered both in pseudoclassical and quantum mechanics. The quantum description uses the hamiltonian in the Foldy--Wouthuysen representation, obtained from the pseudoclassical hamiltonian of the massive charged particle with anomalous magnetic moment in interaction with the external electromagnetic field using Weyl quantization scheme.
Quantization of Electromagnetic Fields in Cavities
NASA Technical Reports Server (NTRS)
Kakazu, Kiyotaka; Oshiro, Kazunori
1996-01-01
A quantization procedure for the electromagnetic field in a rectangular cavity with perfect conductor walls is presented, where a decomposition formula of the field plays an essential role. All vector mode functions are obtained by using the decomposition. After expanding the field in terms of the vector mode functions, we get the quantized electromagnetic Hamiltonian.
Harmonic Electromagnetic Forces in Induction Motors
Fuminori Ishibashi; Makoto Matsushita; Shinichi Noda
2009-01-01
Recently, there has been increasing demand for quiet motors, and the same trend has been observed in the case of induction motors. In induction motors, electromagnetic noise is sometimes the predominant acoustic noise. In small motors, the major cause of vibration and noise is electromagnetic forces resulting from the combination of harmonic fluxes in the air gap. In this study,
Electromagnetic field with constraints and Papapetrou equation
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.
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.
Electromagnetic effects on quasilinear turbulent particle transport
Eriksson, Annika; Weiland, Jan [Radio and Space Science, Chalmers University of Technology and EURATOM-VR Association, S-412 96 Goeteborg (Sweden)
2005-09-15
It is well known that a nonadiabatic part of the electron density response is needed for particle transport in tokamaks. Such main reactive effects are electron trapping and electromagnetic induction. Although electron trapping has been studied rather extensively, electromagnetic effects have hardly been studied at all although they are already included in transport codes. Here the electromagnetic effects have been analyzed and parameter studies have been performed, showing that an electromagnetic particle pinch may appear in the flat density regime, just as for the case of electron trapping although the conditions are more restrictive. The particle pinch is particularly sensitive to the direction of propagation of the eigenmode. The electromagnetic particle flux is found to be outward for modes propagating in the ion drift direction and inward for modes propagating in the electron drift direction. A pinch may be obtained rather close to the axis for International Thermonuclear Experimental Reactor simulation data.
Noninvasive valve monitor using alternating electromagnetic field
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.
Electromagnetic studies in geothermal regions
NASA Astrophysics Data System (ADS)
Berktold, A.
1983-07-01
During the past 25 yr, nearly all available electromagnetic and geoelectric techniques have been tested for their usefulness in geothermal exploration and exploitation. Dipole-dipole profiling, audiomagnetotellurics and controlled source electromagnetic methods are examples of those which have proven to be rather efficient for geothermal exploration. From the hundreds of field surveys which have been performed in many geothermal regions of the world, a large variety of geothermal regions and local geothermal systems, with different geological, hydrological and heat transfer characteristics, has been found to exist. Depending on the combination of these different characteristics each geothermal region or system presents a new problem which may need a different field technique or group of field techniques for optimal exploration. Despite these problems, new geothermal regions have been detected and structures and processes in geothermal systems are now much better understood. For example, advances have been made in the study of (a) the characteristics of porous/permeable hot water/vapor reservoirs and of fractioned zones for hot water/vapor circulation and production (b) the distribution and movement of cold meteoric and of hot water (c) the thermal insulation of reservoirs by cap-rocks (d) convective and/or conductive heat transfer and (e) the thermal influence of magma intrusions to high crustal levels. New exploration techniques, data analysis procedures and model calculations have been developed in the course of research in geothermal areas. They include the controlled source electromagnetic methods, the remote reference field technique and the development of better and faster algorithms for direct and inverse model calculations. Problems for the future are (a) the development and improvement of equipment and field techniques for more precise delineation and resolution of the conductivity distribution in geothermal areas especially those with productive zones of high porosity/permeability and fracturing, (b) the improvement of computerised data analysis in the field to optimise progress during the field measurements and (c) the development of more efficient interpretation procedures for the rather inhomogeneous conductivity distribution which exists in most geothermal areas.
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.
Electromagnetic Induction with Neodymium Magnets
NASA Astrophysics Data System (ADS)
Wood, Deborah; Sebranek, John
2013-09-01
In April 1820, Hans Christian rsted noticed that the needle of a nearby compass deflected briefly from magnetic north each time the electric current of the battery he was using for an unrelated experiment was turned on or off. Upon further investigation, he showed that an electric current flowing through a wire produces a magnetic field. In 1831 Michael Faraday and Joseph Henry separately expanded on rsted's discovery by showing that a changing magnetic field produces an electric current. Heinrich Lenz found in 1833 that an induced current has the opposite direction from the electromagnetic force that produced it. This paper describes an experiment that can help students to develop an understanding of Faraday's law and Lenz's law by studying the emf generated as a magnet drops through a set of coils having increasing numbers of turns.
Formal analysis of electromagnetic optics
NASA Astrophysics Data System (ADS)
Khan-Afshar, Sanaz; Hasan, Osman; Tahar, Sofine
2014-09-01
Optical systems are increasingly being used in safety-critical applications. Due to the complexity and sensitivity of optical systems, their verification raises many challenges for engineers. Traditionally, the analysis of such systems has been carried out by paper-and-pencil based proofs and numerical computations. However, these techniques cannot provide accurate results due to the risk of human error and inherent approximations of numerical algorithms. In order to overcome these limitations, we propose to use theorem proving (i.e., a computer-based technique that allows to express mathematical expressions and reason about their correctness by taking into account all the details of mathematical reasoning) as a complementary approach to improve optical system analysis. This paper provides a higher-order logic (a language used to express mathematical theories) formalization of electromagnetic optics in the HOL Light theorem prover. In order to demonstrate the practical effectiveness of our approach, we present the analysis of resonant cavity enhanced photonic devices.
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.
Electromagnetic launchers for space applications
NASA Technical Reports Server (NTRS)
Schroeder, J. M.; Gully, J. H.; Driga, M. D.
1989-01-01
An electromagnetic launcher (EML) was designed for NASA-Langley to boost large models to hypervelocity for flight evaluation. Two different concepts were developed using railgun and coilgun principles. A coilgun was designed to accelerate a 14-kg mass to 6 km/s and, by adding additional equipment, to accelerate a 10-kg mass to 11 km/s. The railgun system was designed to accelerate only 14 kg to 6 km/s. Of significance in this development is the opportunity to use the launcher for aeroballistic research of the upper atmosphere, eventually placing packages in low earth orbit using a small rocket. The authors describe the railgun and coilgun launch designs and suggest a reconfiguration for placement of 150-kg parcels into low earth orbit for aeroballistic studies and possible space lab support. Each design is detailed along with the performance adjustments which would be required for circular orbit payload placement.
Biological effects of electromagnetic fields
Anderson, L.E.
1991-03-01
Natural background levels of atmospheric electric and geomagnetic field levels are extremely low. Over the past several decades, however, human beings and other life forms on this planet have been subjected to a dramatically changing electromagnetic milieu. Exponential increases in exposure to EM fields have occurred, largely because of technological advances associated with increased use of electricity; e.g. expanding power generation and transmission systems, the increased use of wireless communications, and radar. EM field generating devices have proliferated in industrial plants, office buildings, homes, public transportation systems, and elsewhere. Significant increases have occurred in EM field strengths spanning all frequency ranges; therefore, this paper presents a brief overview of the potential impacts of these fields, primarily at extremely low frequencies (ELF), but also at MW and RF. 2 refs.
Electromagnetic gating in ion channels.
McLeod, B R; Liboff, A R; Smith, S D
1992-09-01
There have been many attempts to develop a theoretical explanation of the phenomena of electromagnetic field interactions with biological systems. None of the reported efforts have been entirely successful in accounting for the observed experimental results, in particular with respect to the reports of interactions between extremely low frequency (ELF) magnetic fields and biological systems at ion cyclotron resonance frequencies. The approach used in this paper starts with the Lorentz force equation, but use is made of cylindrical co-ordinates and cylindrical boundary conditions in an attempt to more closely model the walls of an ion channel. The equations of motion of an ion that result from this approach suggest that the inside shape of the channel plus the ELF magnetic fields at specific frequencies and amplitudes could act as a gate to control the movement of the ion across the cell membrane. PMID:1282185
Advanced studies of electromagnetic scattering
NASA Technical Reports Server (NTRS)
Ling, Hao
1994-01-01
In radar signature applications it is often desirable to generate the range profiles and inverse synthetic aperture radar (ISAR) images of a target. They can be used either as identification tools to distinguish and classify the target from a collection of possible targets, or as diagnostic/design tools to pinpoint the key scattering centers on the target. The simulation of synthetic range profiles and ISAR images is usually a time intensive task and computation time is of prime importance. Our research has been focused on the development of fast simulation algorithms for range profiles and ISAR images using the shooting and bouncing ray (SBR) method, a high frequency electromagnetic simulation technique for predicting the radar returns from realistic aerospace vehicles and the scattering by complex media.
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
Electromagnetic-gravitational energy systems
NASA Technical Reports Server (NTRS)
Schatten, K. H.
1981-01-01
Two methods are considered to 'tap' the earth's rotational energy. This ancient 'collapsed gravitational energy' exceeds the earth-lunar binding energy. One involves an orbiting 'electromagnetic-gravitational' coupling system whereby the earth's rotation, with its nonuniform mass distribution, first uses gravity to add orbital energy to a satellite, similar to a planetary 'flyby'. The second stage involves enhanced satellite 'drag' as current-carrying coils withdraw the added orbital energy as they pass through the earth's nonuniform magnetic field. A second more direct method couples the earth's rotational motion using conducting wires moving through the noncorotating part (ionospheric current systems) of the geomagnetic field. These methods, although not immediately feasible, are considerably more efficient than using pure gravitational coupling to earth-moon tides.
Broadband cavity electromagnetically induced transparency
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.
ELVIS - ELectromagnetic Vector Information Sensor
J. E. S. Bergman; L. hln; O. Stl; B. Thid; S. Ananthakrishnan; J. -E. Wahlund; R. L. Karlsson; W. Puccio; T. D. Carozzi; P. Kale
2005-09-29
The ELVIS instrument was recently proposed by the authors for the Indian Chandrayaan-1 mission to the Moon and is presently under consideration by the Indian Space Research Organisation (ISRO). The scientific objective of ELVIS is to explore the electromagnetic environment of the moon. ELVIS samples the full three-dimensional (3D) electric field vector, E(x,t), up to 18 MHz, with selective Nyqvist frequency bandwidths down to 5 kHz, and one component of the magnetic field vector, B(x,t), from a few Hz up to 100 kHz.As a transient detector, ELVIS is capable of detecting pulses with a minimum pulse width of 5 ns. The instrument comprises three orthogonal electric dipole antennas, one magnetic search coil antenna and a four-channel digital sampling system, utilising flexible digital down conversion and filtering together with state-of-the-art onboard digital signal processing.
Spatially dependent electromagnetically induced transparency.
Radwell, N; Clark, T W; Piccirillo, B; Barnett, S M; Franke-Arnold, S
2015-03-27
Recent years have seen vast progress in the generation and detection of structured light, with potential applications in high capacity optical data storage and continuous variable quantum technologies. Here we measure the transmission of structured light through cold rubidium atoms and observe regions of electromagnetically induced transparency (EIT), using the phase profile as control parameter for the atomic opacity. With q plates we generate a probe beam with azimuthally varying phase and polarization structure, and its right and left circular polarization components provide the probe and control of an EIT transition. We observe an azimuthal modulation of the absorption profile that is dictated by the phase and polarization structure of the probe laser. Conventional EIT systems do not exhibit phase sensitivity. We show, however, that a weak transverse magnetic field closes the EIT transitions, thereby generating phase-dependent dark states which in turn lead to phase-dependent transparency, in agreement with our measurements. PMID:25860744
An electromagnetic black hole made of metamaterials
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.
On the Axioms of Topological Electromagnetism
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.
Electromagnetic Characterization Of Metallic Sensory Alloy
NASA Technical Reports Server (NTRS)
Wincheski, Russell A.; Simpson, John; Wallace, Terryl A.; Newman, John A.; Leser, Paul; Lahue, Rob
2012-01-01
Ferromagnetic shape-memory alloy (FSMA) particles undergo changes in both electromagnetic properties and crystallographic structure when strained. When embedded in a structural material, these attributes can provide sensory output of the strain state of the structure. In this work, a detailed characterization of the electromagnetic properties of a FSMA under development for sensory applications is performed. In addition, a new eddy current probe is used to interrogate the electromagnetic properties of individual FSMA particles embedded in the sensory alloy during controlled fatigue tests on the multifunctional material.
Development of a strong electromagnet wiggler
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.
Development of the strong electromagnet wiggler
Burns, M.J.; Deis, G.A.; Holmes, R.H.; Van Maren, R.D.; Halbach, K.
1988-03-01
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 th4e wiggler field and operate at low current densities by virtue of their placement away from the midplane. The authors describe the design approach used and test data from a 7-period wiggler prototype that includes curved pole tips to provide wiggler-plane focusing.
An AWE Implementation for Electromagnetic Analysis
NASA Technical Reports Server (NTRS)
Gong, Jian; Volakis, John L.
1996-01-01
Although full wave electromagnetic systems are large and cumbersome to solve, typically only a few parameters, such as input impedance, S parameters, and far field pattern, are needed by the designer or analyst. A reduced order modeling of these parameters is therefore an important consideration in minimizing the the CPU requirements. The Asymptotic Waveform Evaluation (AWE) method is one approach to construct a reduced order model of the input impedance or other useful electromagnetic parameters. We demonstrate its application and validity when used in conjunction with the finite element method to simulate full wave electromagnetic problems.
Spinors and pre-metric electromagnetism
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.
Scattering by an electromagnetic radiation field
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.
Conformal array design with transformation electromagnetics
NASA Astrophysics Data System (ADS)
Popa, Bogdan-Ioan; Allen, Jeffery; Cummer, Steven A.
2009-06-01
We apply the theory of transformation electromagnetics to source arrays and show that a complex conformal antenna array can be made to behave like a geometrically different array when surrounded with a properly designed transformation electromagnetics medium. Numerical simulations are presented to show how a nonuniform circular array can be made to radiate and receive as a uniformly spaced linear array. In this way, transformation electromagnetics provides a method by which all of the advantages of simple arrays in array processing, such as beamforming, can be retained in an array whose elements are constrained to a complex geometry.
Counting energy packets in the electromagnetic wave
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.
Cdric Lorc
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.
NASA Astrophysics Data System (ADS)
Tan??l?, Murat; Kansu, Mustafa Emre; Demir, Sleyman
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.
Electromagnetic field radiation model for lightning strokes to tall structures
H. Motoyama; W. Janischewskyj; A. M. Hussein; W. A. Chisholm; J. S. Chang; R. Rusan
1996-01-01
This paper describes observation and analysis of electromagnetic field radiation from lightning strokes to tall structures. Electromagnetic field waveforms and current waveforms of lightning strokes to the CN Tower have been simultaneously measured since 1991. A new calculation model of electromagnetic field radiation is proposed. The proposed model consists of the lightning current propagation and distribution model and the electromagnetic
Reverberating chambers as sources of stochastic electromagnetic fields
Paolo Corona; Giuseppe Ferrara; Maurizio Migliaccio
1996-01-01
Reverberating chambers are of recognized relevance in many EMC applications since they allow us to generate a reference electromagnetic statistical field. This paper investigates the electromagnetic field in reverberating chambers. Reverberating chambers are large overmoded cavities wherein a nonstationary electromagnetic field is present. This electromagnetic field is stochastic in nature; therefore, proper analytical tools need to be considered in order
The Eyjafjallajkull volcanic system, Iceland: insights from electromagnetic measurements
Jones, Alan G.
and ELECTROMAGNETISM, Geomagnetic induction ELECTROMAGNETISM, Remote sensing of volcanoesThe Eyjafjallajökull volcanic system, Iceland: insights from electromagnetic measurements Journal system, Iceland: insights from1 electromagnetic measurements2 Marion P. Miensopust1,2, , Alan G. Jones1
Quantitative interpretation of geophysical electromagnetic data for groundwater investigations
Farquharson, Colin G.
of the subsurface. Electromagnetic induction. Sensitivity of airborne EM measurements. Interpretation apparent of the subsurface. Electromagnetic induction. Sensitivity of airborne EM measurements. Interpretation apparent orders of magnitude. #12;Electromagnetic induction I(t) sin t b #12;Electromagnetic induction Primary H
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.
Advances in non-planar electromagnetic prototyping
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, ...
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.
Tour of the Electromagnetic Spectrum Book
NSDL National Science Digital Library
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.
Dynamic programming applied to electromagnetic satellite actuation
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 ...
Electromagnetic damping of neutron star oscillations
NASA Technical Reports Server (NTRS)
Mcdermott, P. N.; Savedoff, M. P.; Van Horn, H. M.; Zweibel, E. G.; Hansen, C. J.
1984-01-01
A simple model of magnetic field perturbations driven by neutron star oscillations is used to estimate the electromagnetic power radiated by g-modes and torsional oscillations. The calculation assumes that the neutron star has a frozen-in magnetic field which is perturbed by the oscillatory motions of the surface. The disturbances propagate into the vacuum as outgoing electromagnetic waves. The relative effectiveness of Joule heating of the neutron star crust by pulsation-induced electric currents is estimated. It is concluded that electromagnetic damping is the dominant energy dissipation mechanism for quadrupole g-mode oscillations of neutron stars. For dipole spheroidal modes, both electromagnetic radiation and Joule heating are important, and there is no gravitational radiation emitted by these modes.
Advanced high-temperature electromagnetic pump
NASA Technical Reports Server (NTRS)
Gahan, J. W.; Powell, A. H.
1972-01-01
Three phase helical, electromagnetic induction pump for use as boiler feed pump in potassium Rankine-cycle power system is described. Techniques for fabricating components of pump are discussed. Specifications of pump are analyzed.
Electrical wire insulation and electromagnetic coil
Bich, George J. (Penn Hills, PA); Gupta, Tapan K. (Monroeville, PA)
1984-01-01
An electromagnetic coil for high temperature and high radiation application in which glass is used to insulate the electrical wire. A process for applying the insulation to the wire is disclosed which results in improved insulation properties.
Method and apparatus for measuring electromagnetic radiation
NASA Technical Reports Server (NTRS)
Been, J. F. (inventor)
1973-01-01
An apparatus and method are described in which the capacitance of a semiconductor junction subjected to an electromagnetic radiation field is utilized to indicate the intensity or strength of the radiation.
Electromagnetic radiation from beam-plasma instabilities
NASA Technical Reports Server (NTRS)
Stenzel, R. L.; Whelan, D. A.
1982-01-01
The mechanism by which unstable electrostatic waves of an electron-beam plasma system are converted into observed electromagnetic waves is of great current interest in space plasma physics. Electromagnetic radiation arises from both natural beam-plasma systems, e.g., type III solar bursts and kilometric radiation, and from man-made electron beams injected from rockets and spacecraft. In the present investigation the diagnostic difficulties encountered in space plasmas are overcome by using a large laboratory plasma. A finite diameter (d approximately equal to 0.8 cm) electron beam is injected into a uniform quiescent magnetized afterglow plasma of dimensions large compared with electromagnetic wavelength. Electrostatic waves grow, saturate and decay within the uniform central region of the plasma volume so that linear mode conversion on density gradients can be excluded as a possible generation mechanism for electromagnetic waves.
Serpentine Robot Arm Contains Electromagnetic Actuators
NASA Technical Reports Server (NTRS)
Moya, Israel A.; Studer, Philip A.
1994-01-01
Identical modules assembled into flexible robot arm configured in serpentlike fashion to manipulate objects while avoiding obstacles. Each module includes integral electromagnetic actuators energized selectively to produce variety of motions, stationary configurations, and combinations thereof.
Standing Electromagnetic Solitons in Degenerate Relativistic Plasmas
Mikaberidze, G
2015-01-01
The existence of standing high frequency electromagnetic (EM) solitons in a fully degenerate overdense electron plasma is studied applying relativistic hydrodynamics and Maxwell equations. The stable soliton solutions are found in both relativistic and nonrelativistic degenerate plasmas.
Large gap control in electromagnetic levitation.
Banerjee, Subrata; Prasad, Dinkar; Pal, Jayanta
2006-04-01
This paper describes design and implementation of a single axis dc attraction type electromagnetic suspension system where an electromagnet of 2.6 kg mass is levitated over a large gap under a fixed ferromagnetic guide-way. The electromagnet exhibits nonlinear force-current-distance characteristics, and if controllers are to be designed by using linear analysis, the air-gap is restricted to a small region around the chosen nominal operating point. In this work, an attempt has been made to increase the operating range of an electromagnetic suspension system by using the concept of piecewise linear control where the nonlinear force-current-airgap relationships of the magnetic suspension system have been successively linearized at several operating points with a suitable controller designed for each operating point. A novel analog switching scheme has been designed and implemented to automatically switch to the relevant controller depending on the actual air-gap. PMID:16649567
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)
Calculation of electromagnetic force in electromagnetic forming process of metal sheet
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.
Sati, Priti; Tripathi, V. K. [Indian Institute of Technology, Hauz Khas, Delhi 110054 (India)
2012-12-15
Parametric decay of a large amplitude electromagnetic wave into two electromagnetic modes in a rippled density plasma channel is investigated. The channel is taken to possess step density profile besides a density ripple of axial wave vector. The density ripple accounts for the momentum mismatch between the interacting waves and facilitates nonlinear coupling. For a given pump wave frequency, the requisite ripple wave number varies only a little w.r.t. the frequency of the low frequency decay wave. The radial localization of electromagnetic wave reduces the growth rate of the parametric instability. The growth rate decreases with the frequency of low frequency electromagnetic wave.
Modeling semi-anechoic electromagnetic measurement chambers
Christopher L. Holloway; Edward F. Kuester
1996-01-01
Previous studies developed a model to predict theoretically the low-frequency plane-wave reflection coefficient of an array of pyramid cone absorbers such as those used to line anechoic electromagnetic measurement chambers. The present authors apply this model in a geometrical optics approach to predict the electromagnetic field in a chamber lined with cone absorbers in the frequency range of 30-300 MHz.
Electromagnetic and spin polarisabilities in lattice QCD
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.
Geometric phases in multidirectional electromagnetic coupling theory
NASA Astrophysics Data System (ADS)
L?nares, J.; Nistal, M. C.
1992-01-01
Geometric phases are determined for N coupled electromagnetic wave amplitudes evolving in their projective Hilbert space. Multidirectional coupling systems subject to SU ( N) dynamical symmetry are proposed and Aharonov-Anandan phases are evaluated in a spinorial representation, for both closed and partial circuits described by the SU(2) group. Following closely Bhandari's idea, this kind of systems enlarges the general framework of topological phases for electromagnetic waves.
ELECTROMAGNETIC MODELING AND OPTIMIZATION USING NEURAL NETWORKS
Q. J. Zhang
2008-01-01
Electromagnetic modelling and optimization is important for designing high- frequency electronic circuits used in computers and wireless communications. Wireless technologies at higher frequency bands from radio- frequency (RF) to microwave and millimeter-waves are being explored. The push for bandwidth in wireline communication drives the signal speed to m ulti- gigabits per second and beyond. At such high- frequency\\/high-speed, the electromagnetic
Electromagnetic Transport from Microtearing Mode Turbulence
Guttenfelder, W.; Kaye, S. M.; Bell, R. E.; Hammett, G. W.; LeBlanc, B. P.; Mikkelsen, D. R. [Princeton Plasma Physics Laboratory, Princeton New Jersey 08543 (United States); Candy, J. [General Atomics, San Diego, California 92186 (United States); Nevins, W. M.; Wang, E. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Yuh, H. [Nova Photonics Inc., Princeton, New Jersey 08540 (United States)
2011-04-15
This Letter presents nonlinear gyrokinetic simulations of microtearing mode turbulence. The simulations include collisional and electromagnetic effects and use experimental parameters from a high-{beta} discharge in the National Spherical Torus Experiment. The predicted electron thermal transport is comparable to that given by experimental analysis, and it is dominated by the electromagnetic contribution of electrons free-streaming along the resulting stochastic magnetic field line trajectories. Experimental values of flow shear can significantly reduce the predicted transport.
High Frequency Electromagnetic Thermotherapy for Cancer Treatment
Sheng-Chieh Huang; Chih-Hao Huang; Xi-Zhang Lin; Gwo-Bin Lee
Background\\/Aim: Electromagnetic thermotherapy is a new modality for cancer treatment. It applies a highfrequency electrical\\u000a current to generate a magnetic field and heat up magnetic materials for treating targeted cancers. Using such system, we treat\\u000a big tumors (more than 1.5 cm in diameter) in a colon cancer bearing murine model.\\u000a \\u000a Material and Methods: The high-frequency electromagnetic machine has an input
Electromagnetic Transport From Microtearing Mode Turbulence
Guttenfelder, W; Kaye, S M; Nevins, W M; Wang, E; Bell, R E; Hammett, G W; LeBlanc, B P; Mikkelsen, D R
2011-03-23
This Letter presents non-linear gyrokinetic simulations of microtearing mode turbulence. The simulations include collisional and electromagnetic effects and use experimental parameters from a high beta discharge in the National Spherical Torus Experiment (NSTX). The predicted electron thermal transport is comparable to that given by experimental analysis, and it is dominated by the electromagnetic contribution of electrons free streaming along the resulting stochastic magnetic field line trajectories. Experimental values of flow shear can significantly reduce the predicted transport.
Electromagnetic energy transport along Yagi arrays
Stefan A. Maier; Mark L. Brongersma; Harry A. Atwater
2002-01-01
Yagi arrays consisting of closely spaced metal rods (spacing=2 mm, height=14 mm) were investigated as guiding structures for electromagnetic energy in the microwave regime at 8 GHz (?=37 mm) both by experiment and simulation. Information transport is possible at a group velocity of 0.6c. Ninety percent of the electromagnetic energy is confined within a distance of 0.05? from the guiding
Viscoelastic-electromagnetism and Hall viscosity
Yoshimasa Hidaka; Yuji Hirono; Taro Kimura; Yuki Minami
2012-06-04
We introduce a kind of electromagnetism, which we call viscoelastic-electromagnetism, to investigate viscoelastic transport phenomena. It is shown that Cartan's formalism of general relativity is essential for viscoelastic theory, and then the corresponding electric and magnetic fields are regarded as a velocity gradient and a Burgers vector density, respectively. As an application of this formalism, the Streda formula for the Hall viscosity is obtained.
Electromagnetic compatability 1982. Parts 1 & 2
NASA Astrophysics Data System (ADS)
Bem, D. J.; Moron, W.; Struzak, R. G.
The origin, effect, measurement, and control of electromagnetic influences on biological and technological systems are discussed in reports and reviews. Subject areas addressed include electromagnetic compatibility (EMC) and space technology, EMC theory and models, switching and discharge noise sources, antennas, EM fields and propagation, radio communication, immunity, wire communication, lightning, and EMC in power systems. Sections are also devoted to specific noise sources and filters, measurement technology, and EMC and biology.
Electromagnetic Corrections in Staggered Chiral Perturbation Theory
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.
Generating highly uniform electromagnetic field characteristics
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.
Generating highly uniform electromagnetic field characteristics
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.
Generating highly uniform electromagnetic field characteristics
Crow, J.T.
1998-05-05
An apparatus and method are disclosed for generating homogeneous 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. 55 figs.
Generating highly uniform electromagnetic field characteristics
Crow, J.T.
1998-02-10
An apparatus and method for generating homogeneous electromagnetic fields within a volume is disclosed. 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. 39 figs.
Generating highly uniform electromagnetic field characteristics
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.
Generating highly uniform electromagnetic field characteristics
Crow, J.T.
1997-06-24
An apparatus and method are disclosed for generating homogeneous 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. 26 figs.
Ultrashort electromagnetic pulse used for target detection
Chi Ruan; Wei Zhao; Guo-Fu Chen; Bai-Yu Liu; Shao-Lan Zhu
2007-01-01
Two common approaches to generate ultra-short electromagnetic pulse are presented in this paper. One is that using a high-speed avalanche transistor and another is that using a laser triggering photoconductive semiconductor switch (PCSS). An ultra-short electromagnetic pulse with the rise time of 190 picosecond (ps), the pulse duration of 290 ps and the amplitude of 2.2 kV, is radiated by
Donuts make diffractionless electromagnetic waves
NASA Astrophysics Data System (ADS)
Tsai, Ya-Lun; Lu, Jyun-Hong; Chiu, Hua-Kung; Chen, Ching-Yi; Chen, Chii-Chang; Chang, Jenq-Yang
2012-01-01
This work finds that a diffractionless beam can be obtained using periodically arranged donut (torus) waveguides. The Bessel-like field distribution is observed at the output of the waveguide. The structure may be built for electromagnetic waves of any wavelength, including radiowaves, microwaves, infrared light, visible light and UV light. The diameter of the diffractionless beam is of the order of magnitude of the wavelength. For UV light, the structure can be used in near-field high density storage or photolithography. For high-power visible or infrared laser such as a CO2 laser or tera-Watt lasers, the structure can replace collimation lenses to reduce absorption and Fresnel loss. For radiowaves and microwaves, the structure can help directional antenna increase the antenna gain for radar scanning, or highly secure and low-loss communications. The gain media confined in the structure can be adopted to enhance the Purcell effect and thus producing a low-loss and zero-threshold laser.
Octonionic matrix representation and electromagnetism
NASA Astrophysics Data System (ADS)
Chanyal, B. C.
2014-12-01
Keeping in mind the important role of octonion algebra, we have obtained the electromagnetic field equations of dyons with an octonionic 88 matrix representation. In this paper, we consider the eight dimensional octonionic space as a combination of two (external and internal) four-dimensional spaces for the existence of magnetic monopoles (dyons) in a higher-dimensional formalism. As such, we describe the octonion wave equations in terms of eight components from the 8 8 matrix representation. The octonion forms of the generalized potential, fields and current source of dyons in terms of 8 8 matrix are discussed in a consistent manner. Thus, we have obtained the generalized Dirac-Maxwell equations of dyons from an 88 matrix representation of the octonion wave equations in a compact and consistent manner. The generalized Dirac-Maxwell equations are fully symmetric Maxwell equations and allow for the possibility of magnetic charges and currents, analogous to electric charges and currents. Accordingly, we have obtained the octonionic Dirac wave equations in an external field from the matrix representation of the octonion-valued potentials of dyons.
Aircraft Lightning Electromagnetic Environment Measurement
NASA Technical Reports Server (NTRS)
Ely, Jay J.; Nguyen, Truong X.; Szatkowski, George N.
2011-01-01
This paper outlines a NASA project plan for demonstrating a prototype lightning strike measurement system that is suitable for installation onto research aircraft that already operate in thunderstorms. This work builds upon past data from the NASA F106, FAA CV-580, and Transall C-180 flight projects, SAE ARP5412, and the European ILDAS Program. The primary focus is to capture airframe current waveforms during attachment, but may also consider pre and post-attachment current, electric field, and radiated field phenomena. New sensor technologies are being developed for this system, including a fiber-optic Faraday polarization sensor that measures lightning current waveforms from DC to over several Megahertz, and has dynamic range covering hundreds-of-volts to tens-of-thousands-of-volts. A study of the electromagnetic emission spectrum of lightning (including radio wave, microwave, optical, X-Rays and Gamma-Rays), and a compilation of aircraft transfer-function data (including composite aircraft) are included, to aid in the development of other new lightning environment sensors, their placement on-board research aircraft, and triggering of the onboard instrumentation system. The instrumentation system will leverage recent advances in high-speed, high dynamic range, deep memory data acquisition equipment, and fiber-optic interconnect.
Electromagnetic acoustic transducer for NDE
Sato, M.; Sasajima, H. [Toshiba Corp., Kawasaki (Japan); Murai, J.; Noda, T.; Kusa, T. [Toshiba Corp., Tokyo (Japan)
1995-08-01
Non-contacting electromagnetic acoustic transducer (EMAT) has been under development. The EMAT could generate and receive ultrasonic waves through the Lorentz force. It may be possible to simplify preparation works such as pipe coating removal and surface polishing, because the EMAT could conduct ultrasonic testing (UT) without the EMAT contacting to the test surface. The EMAT `s sensitivity is lower than that of the conventional piezoelectric transducer. Also the EMAT`s sensitivity becomes lower as the lift-off between the EMAT and the test surface increases. To detect the ultrasonic wave echo with high signal-to-noise ratio, it is necessary to increase the transmitting energy and reduce the receiver noise. A high-energy transmitter was developed and the crack detection tests were conducted. As a results, it was confirmed that the EMAT could detect 0.5 mm deep notch out. The maximum lift-off was 0.6 mm, which was 3 times larger than that of the existing EMAT.
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.
Acute bioeffects of electromagnetic lithotripsy.
Atahan, O; Alkibay, T; Karao?lan, U; Deniz, N; Bozkirli, I
1996-08-01
Acute effects of extracorporeal shock wave lithotripsy (ESWL) with Siemens Lithostar on kidney and surrounding tissues were examined on 42 patients with unilateral kidney stones in the Department of Urology, Gazi University, Medical Faculty, Ankara, Trkiye. Radiological examinations were done and 24-h urine and blood samples were obtained a day before, the day after and 30 days after ESWL. Urinary excretion of proteins, glycosaminoglycan, and immunoglobulin G were significantly elevated the day after ESWL. Thirty days after excretion levels of these were statistically insignificant in regard to pretreatment levels. Creatinine clearance of the patients was significantly lowered the day after ESWL. One month later differences were insignificant. Excretory urography detected 12 (29%) kidneys with abnormalities the day after ESWL. Thirty days after only 3 (7%) of the kidneys had persistent abnormalities. The number of abnormalities with ultrasonography 24 h and 30 days after ESWL were 15 (36%) and 5 (12%) respectively. With CT-scanning kidney abnormalities 24 h after and 30 days after ESWL were 24 (57%) and 6 (14%) respectively. There was not any statistically significant difference between patients with either radiological or functional changes after ESWL and with patients without these changes in regard to patient age, sex, stone burden and shock wave number. In conclusion, electromagnetic lithotripsy induces acute renal morphologic and functional changes. Functional changes are transient and subside within a month but although decreasing either in size or number some morphologic changes persist during this period. PMID:8908646
Electromagnetic launch of lunar material
NASA Technical Reports Server (NTRS)
Snow, William R.; Kolm, Henry H.
1992-01-01
Lunar soil can become a source of relatively inexpensive oxygen propellant for vehicles going from low Earth orbit (LEO) to geosynchronous Earth orbit (GEO) and beyond. This lunar oxygen could replace the oxygen propellant that, in current plans for these missions, is launched from the Earth's surface and amounts to approximately 75 percent of the total mass. The reason for considering the use of oxygen produced on the Moon is that the cost for the energy needed to transport things from the lunar surface to LEO is approximately 5 percent the cost from the surface of the Earth to LEO. Electromagnetic launchers, in particular the superconducting quenchgun, provide a method of getting this lunar oxygen off the lunar surface at minimal cost. This cost savings comes from the fact that the superconducting quenchgun gets its launch energy from locally supplied, solar- or nuclear-generated electrical power. We present a preliminary design to show the main features and components of a lunar-based superconducting quenchgun for use in launching 1-ton containers of liquid oxygen, one every 2 hours. At this rate, nearly 4400 tons of liquid oxygen would be launched into low lunar orbit in a year.
2010-01-01
Progress in Electromagnetic Research Letters, 19, (2010), 147-154. 1 #12;Electromagnetic wave of electromagnetic (EM) waves by many small particles (bodies), embedded in a thin layer, is studied. Physical: electromagnetic waves; wave scattering by many small bodies; smart materials. 1 Introduction It is known (see, e
[Electromagnetic fields: their biological effects and regulation].
Nakagawa, M
1991-09-01
Concern over the effects of humans of ELF-(extremely low frequency; less than 300 Hz) electromagnetic fields has rapidly increased in recent years. The effects seem to be related to gene level aberrations such as carcinogenesis and developmental malformations, but it is difficult to obtain experimental evidences on field effects. Several safety guidelines or permissible doses have been proposed for electromagnetic wave, but they mainly cover the range of microwave frequencies. Three of the guidelines made in 1989-1990 included ELF-electromagnetic fields and two newly approved guidelines on power-frequency electromagnetic fields appeared in 1990. However, they adopted considerably different values based on different theoretical standpoints. Generally, the concept of electromagnetic fields appears to be confused with that of magnetic field and thus the ideas for protective measures conflict between the two. The author first presented the concepts of electromagnetic and magnetic fields, then briefly discussed their biological effects together with the underlying mechanism, and lastly described these drafts on safety standards or permissible doses. Since subtle and difficult problems remain to be resolved, further investigation will be required in order to put these guidelines into practice. PMID:1753442
ALICE electromagnetic calorimeter prototype test
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.
Is Electromagnetic Gravity Control Possible?
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.
Shizuhiko Deji; Shigeki Ito; Saze Takuya; Kazuyuki Mori; Kunihide Nishizawa
2005-01-01
(SEPDs)caused by high frequency electromagnetic fields emitted from a digital cellular telephone (cell phone)and a card reader of access control system were analyzed. The cases were handcrafted by using cloth of activated carbon fiber, polyester film laminated metal, and two kinds of metal netting. Five kinds of SEPDs put in the cases were exposed to the high frequency electromagnetic fields
Ying-Le Li; Ji-Ying Huang; Ming-Jun Wang
2008-01-01
AbstractThe general image relations of electromagnetic sources are presented around a conductor sphere. The general transformations of trigonometric functions and the unit vectors between two coordinates depart from a distance are obtained. The second scattering field for a target is derived in detail. The complex scattering field and the complex RCS are gained respectively. Results show that the electromagnetic interaction
SCATTERING OF ELECTROMAGNETIC RADIATION BY A COATED PERFECT ELECTROMAGNETIC CONDUCTOR SPHERE
Raphael Ruppin
2009-01-01
An analytic theory for the electromagnetic scattering from a coated perfect electromagnetic conductor (PEMC) sphere is developed. The sphere is characterized by its M parameter, and the coating material by its permittivity and permeability, which may attain arbitrary values, including negative ones. The theory is applied to the calculation of various scattering cross sections. It is found that the scattered
Power law inflation with electromagnetism
Luo, Xianghui; Isenberg, James, E-mail: isenberg@uoregon.edu
2013-07-15
We generalize Ringstrms global future causal stability results (Ringstrm 2009) [11] for certain expanding cosmological solutions of the Einstein-scalar field equations to solutions of the EinsteinMaxwell-scalar field system. In particular, after noting that the power law inflationary spacetimes (M{sup n+1},g{sup -hat}, ?{sup -hat}) considered by Ringstrm (2009) in [11] are solutions of the EinsteinMaxwell-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 Ringstrm (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 EinsteinMaxwell-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 EinsteinMaxwell-scalar field equations. All nearby solutions are geodesically complete. The topology of the initial slice is irrelevant to our stability results.
Electromagnetics for Detecting Shallow Tunnels
NASA Astrophysics Data System (ADS)
Won, I.
2006-05-01
Detecting tunnels by geophysical means, even very shallow ones, has been difficult, to say the least. Despite heavy R&D funding from the military since the early 70s, geophysicists have not produced tools that are simple and practical enough to meet the military needs. The initial interest and R&D funding on the subject perhaps started with the Vietcong tunnels in the 60s. Tunnels in the Korean DMZ, first found in the mid 70s, sharply escalated the R&D spending. During the 90s, covert tunnels along the US-Mexico border have kept the topic alive but at a minimal funding level. Most recent interest appears to be in the terrorism-related shallow tunnels, more or less anywhere in the regions of conflict. Despite the longstanding effort in the geophysical community under heavy public funding, there is a dearth of success stories where geophysicists can actually claim to have found hitherto unknown tunnels. For instance, geophysics has not discovered a single tunnel in Vietnam or in Korea! All tunnels across the Korean DMZ were found from human intelligence. The same is true to all illicit tunnels found along the southwestern border. The tunnels under discussion are clandestine, which implies that the people who built them do not wish others to succeed in finding them. The place around the tunnel, therefore, may not be the friendliest venue for surveyors to linger around. The situation requires tools that are fast, little noticeable, and hardly intrusive. Many geophysical sensors that require ground contacts, such as geophones and electrodes that are connected by a myriad of cables, may not be ideal in this situation. On the other hand, a sensor that can be carried by vehicle without stopping, and is nothing obviously noticeable to bystanders, could be much more acceptable. Working at unfriendly environment also requires forgoing our usual practices where we collect data leisurely and make pretty maps later. To be useful, geophysical tools must be able to process observed data and translate them into actionable results. They may in forms of audio (similar to the beeper of a landmine detector), strip chart, or even a 2D graphic display on a computer screen. In short, the tool must be able to declare a contact, audibly or graphically, in real time or shortly thereafter. In summary, we have two questions here. The first one is if any of the available geophysical tools can detect tunnels. If the answer is yes, then the next question is if any of them are able to perform fast in an unfriendly environment. Electromagnetic sensors may be able to meet the operational requirements: under what circumstances it can find tunnels would be another outstanding question.
Experiments in Electromagnetically Induced Transparency
NASA Astrophysics Data System (ADS)
Kasapi, Athanasios A.
1995-01-01
This dissertation experimentally explores the phenomenon of electromagnetically induced transparency (EIT) in atomic lead vapor. In EIT, a strong 'coupling' laser is applied to a 3-state atomic medium, rendering the medium transparent to a probe laser tuned near a resonance transition. A novel conceptional result of this dissertation is a three dimensional vector model for the evolution of a 3-state atom under the influence of these two lasers. Pulse propagation dynamics are clearly observed for the first time; in the small signal regime, these dynamics include a very slow optical group velocity for a 14-ns -long probe laser pulse propagating through gas-phase atomic lead (manifesting itself an optical delay of 55 ns through a 10-cm-long cell), and a dramatic clearing of increase in transparency from exp(-6000) to exp( -1). In the strong probe pulse regime, new propagation dynamics similar to the theoretically predicted adiabatons are observed. In addition, the spatial beam profile of a high-intensity probe beam is preserved, indicating that EIT inhibits nonlinear effects that distort the phase and amplitude of a spatial beam profile in an atomic medium when no coupling laser is present. A new laser method for determining one-photon transition linewidths is demonstrated, where the laser need only be tunable and have a narrow linewidth. An analogous method for two-photon transitions is demonstrated as well (based in EIT), in which the lasers need only be tunable to one and two-photon resonance, where they are held while the coupling laser intensity is varied to determine the linewidth. Finally, a new technique using EIT to discriminate between isotopes of the same atomic element is demonstrated. In this technique, one isotope is rendered transparent to a probe laser while in another isotope, a strong transition is Stark-shifted into resonance with the probe laser pulse, enhancing the atom-laser interaction. The two laser systems used in the experiments are pulsed Ti:sapphire lasers seeded with external cavity diode lasers, doubled and tripled to 406 and 283 nm.
Electromagnetic wave absorption characteristics of multiwalled carbon nanocoils
NASA Astrophysics Data System (ADS)
Eguchi, Usaburo; Takikawa, Hirofumi; Suda, Yoshiyuki
2014-04-01
We have studied the electromagnetic wave absorption properties of a multiwalled carbon nanocoil (MWCNC), a promising lightweight and wide-band electromagnetic wave absorber. Experiments were conducted using several types of paste with various weight concentrations of MWCNC compounded into an organic binder. The results revealed the significant electromagnetic wave absorption potential of the MWCNC. They also verified that its electromagnetic wave absorption effect is strongly dependent on MWCNC concentration, so that there is an optimal MWCNC composition. The increased sample thickness enhances electric conduction loss and encourages electromagnetic wave absorption, even in a high-frequency range. Consequently, the MWCNC has been demonstrated as a new outstanding electromagnetic wave absorber.
Electromagnetic energy momentum in dispersive media
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.
Electromagnetically induced absorption via incoherent collisions
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.
Complex geometry and pre-metric electromagnetism
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.
Inverse and control problems in electromagnetics
NASA Astrophysics Data System (ADS)
Kleinman, Ralph E.; Angell, Thomas S.
1994-10-01
This report summarizes work carried out in a number of specific areas of investigation in inverse scattering and optimal control problems in electromagnetics. The progress is briefly described and detailed results are included in an appendix. The major accomplishments include: the application of multi-criteria optimization techniques to problems in antenna design; the development of inverse scattering algorithms which use scattered field data in the frequency domain to reconstruct the shape, location and constitutive parameters of a scattering object; establishing the well-posedness of electromagnetic scattering problems with resistive or conductive boundary conditions; and derivation of new boundary integral equations for electromagnetic scattering from local distributions of a plane screen. In addition some new results on low frequency scattering have been found which establish the exact nature of the asymptotic expansion in two dimensions.
Apparatus for processing electromagnetic radiation and method
NASA Technical Reports Server (NTRS)
Gatewood, George D. (Inventor)
1983-01-01
Measuring apparatus including a ruled member having alternate transparent and opaque zones. An optical coupler connecting the ruled member with electromagnetic radiation-conversion apparatus. The conversion apparatus may include a photomultiplier and a discriminator. Radiation impinging on the ruled member will, in part, be converted to electrical pulses which correspond to the intensity of the radiation. A method of processing electromagnetic radiation includes providing a member having alternating dark and light zones, establishing movement of the member through the beam of electromagnetic radiation with the dark zones interrupting passage of radiation through the rule, providing an optical coupler to connect a portion of the radiation with a conversion station where the radiation portion is converted into an electrical pulse which is related to the intensity of the radiation received at the conversion station. The electrical pulses may be counted and the digitized signals stored or permanently recorded to produce positional information.
Electromagnetic Radiations as a Fluid Flow
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.
Electromagnetically driven dwarf tornados in turbulent convection
NASA Astrophysics Data System (ADS)
Kenjere, Saa
2011-01-01
Motivated by the concept of interdependency of turbulent flow and electromagnetic fields inside the spiraling galaxies, we explored the possibilities of generating a localized Lorentz force that will produce a three-dimensional swirling flow in weakly conductive fluids. Multiple vortical flow patterns were generated by combining arrays of permanent magnets and electrodes with supplied dc current. This concept was numerically simulated and applied to affect natural convection flow, turbulence, and heat transfer inside a rectangular enclosure heated from below and cooled from above over a range of Rayleigh numbers (104<=Ra<=5109). The large-eddy simulations revealed that for low- and intermediate-values of Ra, the heat transfer was increased more than five times when an electromagnetic forcing was activated. In contrast to the generally accepted view that electromagnetic forcing will suppress velocity fluctuations and will increase anisotropy of turbulence, we demonstrated that localized forcing can enhance turbulence isotropy of thermal convection compared to its neutral state.
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.
Electromagnetic response of strongly coupled plasmas
NASA Astrophysics Data System (ADS)
Forcella, Davide; Mezzalira, Andrea; Musso, Daniele
2014-11-01
We present a thorough analysis of the electromagnetic response of strongly coupled neutral plasmas described by the gauge/gravity correspondence. The coupling of the external electromagnetic field with the tower of quasi-normal modes of the plasmas supports the presence of various electromagnetic modes with different properties. Among them we underline the existence of negative refraction with low dissipation for a transverse mode. Previous hydrodynamical approaches have shown the ubiquitous character of negative refraction in charged plasmas and the absence thereof in neutral plasmas. Our results here extend the analysis for neutral plasmas beyond the hydrodynamical regime. As an application of these new insights we briefly discuss the case of the quark gluon plasma in the temperature dominated regime.
Gravitational sources of purely electromagnetic origin
NASA Astrophysics Data System (ADS)
Tiwari, R. N.; Rao, J. R.; Ray, Saibal
1991-04-01
The feasibility of developing an equation of state is examined for an electromagnetic mass model which is not under tension. The analysis attempts to dispense with the invariant relation described by Tiwari et al. (1984) in which a repulsive source describes the mass model. By considering the Einstein-Maxwell field equations for charged dust corresponding to an axially symmetric line element of Levi-Civita (1919), it is shown that the compatibility of the charged fluid source and the axially symmetric field exists when the pressure vanishes. The charged dust distributions are first considered to have only electromagnetic origins, and then the distributions are examined in cases where certain conditions are necessary for electromagnetic origins to exist. The solution for the source of the Curzon (1924) particle field, and the exterior field of an electron can be described by the source of the 'Reissner-Nordstrom-Curzon' field.
Strong Scalar QED in Inhomogeneous Electromagnetic Fields
Sang Pyo Kim
2008-02-06
Strong QED has attracted attention recently partly because many astrophysical phenomena have been observed to involve electromagnetic fields beyond the critical strength for electron-positron pair production and partly because terrestrial experiments will generate electromagnetic fields above or near the critical strength in the near future. In this talk we critically review QED phenomena involving strong external electromagnetic fields. Strong QED is characterized by vacuum polarization due to quantum fluctuations and pair production due to the vacuum instability. A canonical method is elaborated for pair production at zero or finite temperature by inhomogeneous electric fields. An algorithm is advanced to calculate pair production rate for electric fields acting for finite periods of time or localized in space or oscillating electric fields. Finally, strong QED is discussed in astrophysics, in particular, strange stars.
Tracing buried pipelines using multi frequency electromagnetic
NASA Astrophysics Data System (ADS)
El-Qady, Gad; Metwaly, Mohamed; Khozaym, Ashraf
2014-06-01
In this paper the application of multi frequency electromagnetic techniques to locate buried pipelines is described. The survey site has two pipelines of SUMED, one of the world chokepoints. At desert or arid areas, regular geophysical surveys usually are difficult to carry out. EM techniques could be the best among geophysical techniques to be used for this target at these conditions. The EM survey was performed using a GEM-300 multi-frequency electromagnetic profiler. It is of handheld electromagnetic induction-type that measures in-phase and quadrature terrain conductivity without electrodes or direct soil contact. An area of 60 15 m was surveyed, that supposed SUMED pipeline existed. Six different frequencies, typically 2025, 2875, 4125, 5875, 8425, 12,025 Hz, have been used simultaneously. The slice maps for in-phase and conductivity distribution at each frequency could help to trace the extension of the pipeline. Two pipelines were traced successfully with 20 m spacing of each others.
Electromagnetic moments of quasi-stable baryons
T. Ledwig; J. Martin-Camalich; V. Pascalutsa; M. Vanderhaeghen
2011-04-19
We address electromagnetic properties of quasi-stable baryons in the context of chiral extrapolations of lattice QCD results. For particles near their decay threshold we show that the application of a small external magnetic field changes the particle's energy in a non-analytic way. Conventional electromagnetic moments are only well-defined when the background field B satisfies |eB|/(2M_*|M_*-M-m|) where M_* is the mass of the resonance and M, m the masses of the decay products. An application of this situation is the chiral extrapolation of Delta(1232)-isobar electromagnetic properties. We discuss such an extrapolation of the Delta(1232)-isobar magnetic dipole, electric quadrupole and magnetic octupole moments by a covariant chiral effective field theory.
Drift effects on electromagnetic geodesic acoustic modes
NASA Astrophysics Data System (ADS)
Sgalla, R. J. F.
2015-02-01
A two fluid model with parallel viscosity is employed to derive the dispersion relation for electromagnetic geodesic acoustic modes (GAMs) in the presence of drift (diamagnetic) effects. Concerning the influence of the electron dynamics on the high frequency GAM, it is shown that the frequency of the electromagnetic GAM is independent of the equilibrium parallel current but, in contrast with purely electrostatic GAMs, significantly depends on the electron temperature gradient. The electromagnetic GAM may explain the discrepancy between the f 40 kHz oscillation observed in tokamak TCABR [Yu. K. Kuznetsov et al., Nucl. Fusion 52, 063044 (2012)] and the former prediction for the electrostatic GAM frequency. The radial wave length associated with this oscillation, estimated presently from this analytical model, is ?r 25 cm, i.e., an order of magnitude higher than the usual value for zonal flows (ZFs).
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.
Group theoretical description of artificial electromagnetic metamaterials.
Padilla, Willie J
2007-02-19
Point group theoretical methods are used to determine the electromagnetic properties of metamaterials, based solely upon the symmetries of the underlying constituent particles. From the transformation properties of an electromagnetic (EM) basis under symmetries of the particles, it is possible to determine, (i) the EM modes of the particles, (ii) the form of constitutive relations (iii) magneto-optical response of a metamaterial or lack thereof. Based upon these methods, we predict an ideal planar artificial magnetic metamaterial, and determine the subset of point groups of which particles must belong to in order to yield an isotropic 3D magnetic response, and we show an example. PMID:19532398
Electromagnetic Observables in Few-Nucleon Systems
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.
Duality in Off-Shell Electromagnetism
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.
Environmental and Occupational Exposure to Electromagnetic Fields
Maria A. Stuchly; Kjell Hansson Mild
1987-01-01
Magnetic fields fromhigh-voltage powertransmission lines varywiththeline current. Foratransmission line carrying 0.5 ELECTROMAGNETIC FIELDSencompass a widerangeof to2kA,magnetic flux densities of10to40MuT areproduced frequencies, froma fewHztotensofGHz.Naturally within adistance of40mfromtheline center.(In airandother occurring ambient fields atthesefrequencies arerather weak. materials whoserelative permeability isone,1MuT = 0.796A\\/ Electromagnetic fields andwaves areusedforvariousm.)Thefluxdensities fall offrapidly withdistance, andat purposes thatgreatly benefit mankind, buttheseusesare 100m fromthecenter line, thefluxdensity isabout1AT[3]. frequently-accompanied byanincrease
Electromagnetic mass model admitting conformal motion
Saibal Ray; A A Usmani; F Rahaman; M Kalam; K Chakraborty
2008-06-22
We study charged fluid spheres under the 4-dimensional Einstein-Maxwell space-time. The solutions thus obtained admitting conformal motion. We also investigate whether the solutions set provide electromagnetic mass models such that the physical parameters including the gravitational mass arise from the electromagnetic field alone. In this connection three cases are studied here in detail with the propositions: (1) $p = - \\rho$, (2) $\\sigma e^{\\lambda/2} = \\sigma_0$ and (3) $8 \\pi p - E^2 = p_0$ where $\\rho$, $p$, $\\sigma$ are respectively the usual matter density, fluid pressure and charge density of the spherical distribution. Based on these assumptions several features are explored which seems physically very interesting.
Electromagnetic continuous casting project: Final report
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.
Electromagnetic wave collapse in a radiation background
Mattias Marklund; Gert Brodin; Lennart Stenflo
2003-10-17
The nonlinear interaction, due to quantum electrodynamical (QED) effects, between an electromagnetic pulse and a radiation background is investigated, by combining the methods of radiation hydrodynamics with the QED theory for photon-photon scattering. For the case of a single coherent electromagnetic pulse we obtain a Zakharov-like system, where the radiation pressure of the pulse acts as a driver of acoustic waves in the photon gas. For a sufficiently intense pulse and/or background energy density there is focusing and subsequent collapse of the pulse. The relevance of our results for various astrophysical applications are discussed.
Null electromagnetic fields and relative CR embeddings
Jonathan Earl Holland; George Sparling
2012-02-06
This paper applies the notion of relative CR embeddings to study two related questions. First, it answers negatively the question posed by Penrose whether every shear-free null rotating congruence is analytic. Second, it proves that given any shear-free null rotating congruence, there exists a null electromagnetic field which is null with respect to the given congruence. In the course of answering these questions, we introduce some new techniques for studying null electromagnetic fields and shear-free congruences in general based on the notion of a relative CR embedding.
Scanning evanescent electro-magnetic microscope
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.
Scanning evanescent electro-magnetic microscope
Xiang, Xiao-Dong (Alameda, CA); Gao, Chen (Anhui, CN); Schultz, Peter G. (La Jolla, CA); Wei, Tao (Sunnyvale, CA)
2003-01-01
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.
Electromagnetic waves, gravitational coupling and duality analysis
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.
Electromagnetic Waves in the De Sitter Space
V. S. Otchik; V. M. Red'kov
2010-01-24
5-Dimensional wave equation for a massive particle of spin 1 in the background of de Sitter space-time model is solved in static coordinates. The spherical 5-dimensional vectors $A_{a}, a= 1,...,5$ of three types, $j,j+1, j-1$ are constructed. In massless case they give electromagnetic wave solutions, obeying the Lorentz condition. 5-form of equations in massless case is used to produce recipe to build electromagnetic wave solutions of the types $\\Pi, E,M$; the first is trivial and can be removed by a gauge ransformation. The recipe is specified to produce spherical $\\Pi, E, M$ solutions in static coordinates.
Electromagnetic processes and the diquark model
Peter Kroll
1997-09-23
The present status of the diquark model for exclusive reactions at moderately large momentum transfer is reviewed. That model is a variant of the Brodsky-Lepage approach in which diquarks are considered as quasi-elementary constituents of baryons. Recent applications of the diquark model, relevant to high energy physics with electromagnetic probes, are discussed: electromagnetic form factors of baryons in both the space-like and the time-like region, two-photon annihilations into proton-antiproton pairs as well as real and virtual Compton scattering.
Self-imaging of electromagnetic fields
NASA Astrophysics Data System (ADS)
Tervo, Jani; Pekka Turunen, Jari
2001-12-01
The electromagnetic theory of self-imaging fields is considered. Several features are presented, which have no counterparts within the scalar theory of self-imaging. For example, the electromagnetic field self-images at one half of the classical self-imaging distance for scalar fields, the electric and magnetic energy densities can self-image while the scalar field components do not, and the self-imaging distances of the electric and magnetic energy densities can be different. In addition, general expressions for TE and TM polarized fields are presented by using the concept of the angular spectrum of the field.
Multifunctional composites and structures with integrated mechanical and electromagnetic properties
Amirkhizi, Alireza Vakil
2006-01-01
HFSS finite- element electromagnetic software (Ansoft,HFSS finite- element electromagnetic software (Ansoft,software packages for numerical simulation: ( i ) Ansoft-HFSS (Ansoft, 2001), a commercial finite-element
Low frequency electromagnetic radiation from sprite streamers Jianqi Qin,1
Pasko, Victor
. Introduction [2] Simultaneous observations of sprite-associated Extremely Low Frequency (ELF) radio and produce electromagnetic radiation observed typically in the extremely low (ELF) to ultra low (ULFLow frequency electromagnetic radiation from sprite streamers Jianqi Qin,1 Sebastien Celestin,1
Passive electromagnetic damping device for motion control of building structures
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 ...
Sensitivity of electromagnetic waves to a heterogeneous bianisotropic structure
Cerveny, Vlastislav
Sensitivity of electromagnetic waves to a heterogeneous bianisotropic structure Ludek Klimes for the scattered Gaussian packets without derivation. The derivation for the electromagnetic waves is analogous of a generally heterogeneous bianisotropic structure manifest themselves in the wave field, and which
Propagation Analysis of Electromagnetic Waves: Application to Auroral Kilometric Radiation
Santolik, Ondrej
12 Propagation Analysis of Electromagnetic Waves: Application to Auroral Kilometric Radiation Kilometric Radiation (AKR). We give a brief tutorial description of the background considerations useful words: Electromagnetic waves in plasmas, direction finding, wave distribution function, auroral
Electromagnetic Light in Medium of Polarized Atoms $^3$He
V. N. Minasyan
2009-04-01
First, it is predicted that polarized atoms $^3$He increase a value of speed electromagnetic waves. This reasoning implies that the velocity of electromagnetic waves into gas consisting of polarized atoms $^3$He is rather than one in vacuum.
6th International Conference in Airborne Electromagnetics (AEM 2013)
NASA Astrophysics Data System (ADS)
Davis, Aaron
2015-02-01
This special issue of Exploration Geophysics comprises papers from the 6th International Conference in Airborne Electromagnetics (AEM 2013) held in South Africa, and showcases the latest ideas and advancements in the discipline of airborne electromagnetic geophysics.
Controlling Electromagnetic Surface Waves with Scalar and Tensor Impedance Surfaces
Sarabandi, Kamal
Controlling Electromagnetic Surface Waves with Scalar and Tensor Impedance Surfaces by Amit M.1 Background on Electromagnetic Metasurfaces . . . . . . . . . 1 1.2 Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . 6 1.4.1 Chapter II: Sinusoidally-Modulated Scalar Impedance Surfaces . . . . . . . . . . . . . . . . . . . .
Phenomenological dispersive effects in scalar, pseudoscalar, electromagnetic propagation
C. Wolf
1990-01-01
By assuming a general Lagrangian for the interaction of scalar and pseudoscalar fields with the electromagnetic field, we calculate the dispersion in frequency of scalar, pseudoscalar electromagnetic waves in an external magnetic field.
On the gravitational fields created by the electromagnetic waves
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.
Target Detection and Characterization from Electromagnetic Induction Data
Target Detection and Characterization from Electromagnetic Induction Data Habib Ammari Junqing Chen for imaging small volume conduc- tive inclusions of arbitrary shapes from electromagnetic induction data, induction data, asymptotic formula, detection test, localization, charac- terization, Hadamard technique
ECE 341: Electromagnetic Fields I EM devices and systems
Schumacher, Russ
in material media - Electromagnetic induction - Inductance - Magnetic energy Applications: - ElectronicsECE 341: Electromagnetic Fields I EM devices and systems - Can compute and analyze potentials compositions - Can evaluate capacitance, inductance, resistance, and conductance of EM structures - Understands
Broadband electromagnetic scattering by particles Michael I. Mishchenko
Broadband electromagnetic scattering by particles Michael I. Mishchenko NASA Goddard Institute, in fact, questionable and do not fol- low from the fundamental concept of electromagnetic scattering constitutive relations, which state that the electric displacement D, the magnetic induction B
Evaluation of Electromagnetic Induction as a Reconnaissance Technique to Characterize
Scanlon, Bridget R.
296 Evaluation of Electromagnetic Induction as a Reconnaissance Technique to Characterize The use of apparent electrical conductivity (ECa) measured with electromagnetic (EM) induction Introduction Noninvasive techniques such as EM induction are becoming increasingly popular because they can
Finite element analysis of transient electromagnetic heating effects in three dimensions
NASA Astrophysics Data System (ADS)
Bisson, S. H. L. G.; Leonard, P. J.; Rodger, D.; Leyden, C.
1993-01-01
Electromagnetic finite element analysis was used to model the 2D instantaneous heating effects under a Bath University MEGA electromagnetic FE program. A full 3D coupled electromagnetic heating model based on the MEGA electromagnetic finite element code is described.
Effective launch package integration for electromagnetic guns
T. E. Hayden; R. Dethlefsen; J. H. Price
1995-01-01
Many engineering disciplines must be considered when designing launch packages for electromagnetic guns. These include electromechanics, plasma physics, fluid dynamics, structures, materials science, aerodynamics, thermodynamics, flight dynamics, and terminal effects. Often, the requirements of one discipline will be in direct conflict with the requirements of another. Each discipline can claim to be of overriding importance, but all aspects of launch
Unique Signal Override Plug electromagnetic test report
Bonn, R.H.
1990-10-01
The MC4039 Unique Signal Override Plug (USOP) provides the unique signal for the B90 when fielded on aircraft that are not equipped with unique signal capability. Since the USOP is field installed, the concern is that it might be susceptible to electromagnetic radiation prior to installation on the weapon. This report documents a characterization of the USOP, evaluates various techniques for attaching electromagnetic shields, and evaluates the susceptibility of a fully assembled passive-USOP. Tests conducted evaluated the electromagnetic susceptibility of the passive, unconnected USOP. During normal operation the USOP is powered directly from the weapon. During the course of this test program two prototypes were developed. The prototype 1 USOP internal circuitry contains one SA3727 chip, five diodes, three resistors, and two capacitors; these are mounted on a circular circuit board and contained inside a metal back shell cover, which serves as an electromagnetic shield. The prototype 2 design incorporated four changes. The manufacturer of the SA3727 chip was changed from Lasarray to LSI Logic, the circuit board ground was tied to the case ground through a straight wire, Cl was changed from 1 microfarad to 0.1 microfarads. and the circuit board was changed, as required. 2 refs., 17 figs., 3 tabs. (JF)
Electromagnetic Flaw Detector Is Easier To Use
NASA Technical Reports Server (NTRS)
Clendenin, C. Gerald; Namkung, Min; Simpson, John W.; Fulton, James P.; Wincheski, Buzz; Todhunter, Ronald G.
1994-01-01
Electromagnetic flaw detector based on eddy-current principle. It nondestructively detects cracks, voids, and other flaws introducing electrical discontinuities into specimens of electrically conductive materials. Circuitry associated with this flaw detector simpler than older eddy-current flaw detectors. Unlike older eddy-current nondestructive testers, calibration ordinarily not needed, and readings interpreted with relative ease.
Electromagnetic properties of generalized Majorana particles
Boudjema, F.; Hamzaoui, C.; Rahal, V.; Ren, H.C.
1989-02-20
We prove a theorem stating that a massive Majorana particle (a CPT-self-conjugate particle) with arbitrary spin J can possess only an anapole moment and multipoles of that. We also show that massless Majorana particles, except those of spin (1/2, do not have any single-photon electromagnetic form factor.
Development of an advanced electromagnetic gun barrel
T. W. Hurn; J. D'Aoust; L. Sevier; R. Johnson; J. Wesley
1993-01-01
An advanced electromagnetic gun (AEMG) barrel was developed for the US Air Force Wright Laboratory (Armament Directorate) to repetitively accelerate large mass projectiles. The AEMG barrel used 5-m rails, had a 50-mm square bore, and was designed to operate at a peak current of 1.5 MA (bore pressure 25 ksi). Key technical achievements included (1) an efficient barrel containment structure
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.
Heating activated carbon by electromagnetic induction
P. Mocho; J. Ch. Bourhis; P. Le Cloirec
1996-01-01
The purpose of this study is the use of electromagnetic induction to heat activated carbon. The ultimate goal is to get an original process to regenerate adsorbants loaded with the volatile organic compounds present in air or water.The first step was to explore the possibilities of heating granular activated carbon with this technology. In order to get the best operating
Active source electromagnetic methods for marine munitions
NASA Astrophysics Data System (ADS)
Schultz, Gregory; Shubiditze, Fridon; Miller, Jonathan; Evans, Rob
2011-06-01
The detection of munitions targets obscured in coastal and marine settings has motivated the need for advanced geophysical technologies suited for underwater deployment. Building on conventional marine electromagnetic theory and based on the use of existing electric and magnetic field sensing designs, we analyze the electromagnetic fields emitted from excited targets in the frequency range between 1 kHz and 1 MHz. We present evidence that employing electromagnetic modes that are higher in frequency relative to those typically used in ground-based sensing yields greater range and sensitivity for underwater surveys. We develop potential design strategies for implementing both magnetic (B) and electric (E) field sources and sensors in the marine environment, and determine optimal arrangements for a potential combined E- and B-field sensing system. The implementation of both 1D analytical and 3D numerical simulations yields the primary and secondary field distributions in representative underwater settings for various sourcereceiver arrangements. We study the electromagnetic field distributions from both electric (voltage-fed dipole) and magnetic field (encased and submerged induction coil) active sources. Application of these concepts provide unique and useful information about targets from the addition of electric field sensing alone as well as through the combination of electric and magnetic field sensing.
Line geometry and electromagnetism I: basic structures
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.
The behavior of electromagnetic fields at edges
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
Electromagnetic Siegert states for periodic dielectric structures
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.
Electromagnetic optimization exploiting aggressive space mapping
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
Vibration isolation using a shunted electromagnetic transducer
Sam Behrens; Andrew J. Fleming; S. O. Reza Moheimani
2004-01-01
By attaching an electromagnetic transducer to a mechanical isolation system and shunting the terminals of the transducer with electrical impedance, we can provide improved isolation performance while eliminating the need for an additional sensor. Simulated and experimental results on a simple electro-mechanical isolation system show that the proposed controller is capable of peak damping and high frequency attenuation.
Complementary Electromagnetic Non-Destructive Evaluation
NASA Astrophysics Data System (ADS)
Tian, Gui Yun; Wilson, John; Morozov, Maxim
2011-06-01
The use of non-destructive evaluation (NDE) for defect detection and failure prediction in structures and specimens is widespread in energy industries, aimed at ageing power plants and pipelines, material degradation, fatigue and radiation damage, etc. At present there are no suitable electromagnetic NDE methods for the measurement and characterization of material degradation, in irradiated samples in particular, which is very important and timely for the nuclear power industry in the UK. This paper reports recent developments in the field of electromagnetic (EM) NDE at Newcastle University, including pulsed eddy current (PEC), pulsed magnetic flux leakage (PMFL), magnetic Barkhausen emission (MBE) and magneto-acoustic emission (MAE). As different EM methods have different strengths, an integrative EM framework is introduced. Case studies through the second round robin tests organized by the Universal Network for Magnetic Non-Destructive Evaluation (UNMNDE), representing eighteen leading research groups worldwide in the area of electromagnetic NDE, are reported. Twelve samples with different ageing times and rolling reduction ratios were tested using different magnetic methods among the UNMNDE members. Based on the studies, the complementary characteristics of electromagnetic techniques for NDE are discussed.
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
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.
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)
Electromagnetic visualization for antennas and scattering
J. Shaeffer; B. Cooper
1999-01-01
Numerical electromagnetic modeling involves three distinct phases: the preparation of the geometric input data; running the numerical model; and evaluation or viewing\\/visualization of the model output. This paper presents visualization examples for frequency domain codes. Visualization quantities for antenna and scattering examples include geometry, currents, near fields, radiation images, and far field patterns that can be animated in time and
Health effects of exposure to electromagnetic fields
Maria A. Stuchly
1995-01-01
There are numerous sources of radio frequency and microwave fields to which people are exposed in the course of their work or everyday life. These fields provide the society with invaluable services such as communication, navigation, defense and many other benefits. At the same time electromagnetic fields are known to interact with the human body and under some circumstances may
On the execution of electromagnetic field courseware
Feng-Wei Yao; Shun-Shi Zhong
2004-01-01
Electromagnetic field courseware using PowerPoint as the flat, integrating with Mathematica and Flash has been introduced. Dynamic animated computer graphics and 3D colorful pictures have shown more advantages than the traditional teaching. We believe that modern educational technology, which has multimedia as kernel, will change not only the means and modes of teaching, but also the ideas of education in
Electromagnetic field of a linear antenna
Norman Derby; Stanislaw Olbert
2008-01-01
Animated computer simulations of the electric field of a radiating antenna can capture the attention of students in introductory electromagnetism courses and stimulate active discussions. The simulations raise questions not usually addressed in textbooks. In certain cases, some of the field lines appear to move toward the antenna, the speed of the field lines can change as they move, and
Potential formalisms in electromagnetic-field analysis
Natalia K. Georgieva; Helen W. Tam
2003-01-01
The theory of electromagnetic (EM) potentials is as old as the Maxwell equations, which treat the field vectors E and H directly. Yet the vector and scalar potentials are often regarded as nothing more than an auxiliary mathematical concept, which does not necessarily reflect a physically existing phenomenon. This widely accepted opinion does not have sound theoretical or experimental validation.
Teaching electromagnetic field theory using differential forms
Karl F. Warnick; Richard H. Selfridge; David V. Arnold
1997-01-01
The calculus of differential forms has significant advantages over traditional methods as a tool for teaching electromagnetic (EM) field theory. First, films clarify the relationship between field intensity and flux density, by providing distinct mathematical and graphical representations for the two types of fields. Second, Ampere's and Faraday's laws obtain graphical representations that are as intuitive as the representation of
Modeling of Electromagnetic Damper for Automobile Suspension
Yasuhiro Kawamoto; Yoshihiro Suda; Hirofumi Inoue; Takuhiro Kondo
2007-01-01
In this paper, the modeling of the electromagnetic damper (EMD) for automobile suspension is presented and the validation of the model is demonstrated by comparing the numerical results with the experimental results obtained using shaker tests. EMD is used as an active suspension and controlled to have output force calculated from velocities of sprung and unsprung masses. The formulation of
ELECTROMAGNETIC MATCHED FIELD PROCESSING FOR SOURCE LOCALIZATION
Gerstoft, Peter
mental parameter estimation have not previously been ap plied in the electromagnetic domain associated with the propagation of the source signal. While methods for estimating environ mental parameters it was assumed that all parameters except for two (e.g., source range and depth for MFP using a vertical ar ray
Alternating current electromagnetic servo induction meter
NASA Technical Reports Server (NTRS)
Bogue, R. K.
1968-01-01
Electromagnetic device accurately indicates the responses of various sensors in high performance flight research aircraft to conditions encountered in flight. The device responds to sensor inputs to move a slideable armature along an indicator scale by the force of currents induced in the armature winding.
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.
Optimization of an Electromagnetic Energy Harvesting Device
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
New variables for gyrokinetic electromagnetic simulations
Mishchenko, Alexey, E-mail: alexey.mishchenko@ipp.mpg.de; Cole, Michael; Kleiber, Ralf; Knies, 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 Alfvn Eigenmode at low perpendicular mode numbers, the so-called magnetohydrodynamical limit, has been successfully simulated using this method.
An electromagnetic energy coupler for medical applications
M. F. Iskander; C. H. Durney
1979-01-01
An applicator for coupling electromagnetic (EM) energy into a dielectric material such as tissue is described. The applicator is a section of a surface strip transmission line which has proved to couple the EM energy efficiently and with minimal radiation leakage around the body. It is also small, light, and flat, and hence, suitable for medical applications.
Electromagnetic Radiation and Motion of Real Particle
Jozef Klacka
2001-06-21
Relativistically covariant equation of motion for real dust particle under the action of electromagnetic radiation is derived. The particle is neutral in charge. Equation of motion is expressed in terms of particle's optical properties, standardly used in optics for stationary particles.
Out-of-equilibrium electromagnetic radiation
Julien Serreau
2004-06-22
We derive general formulas for photon and dilepton production rates from an arbitrary non-equilibrated medium from first principles in quantum field theory. At lowest order in the electromagnetic coupling constant, these relate the rates to the unequal-time in-medium photon polarization tensor and generalize the corresponding expressions for a system in thermodynamic equilibrium. We formulate the question of electromagnetic radiation in real time as an initial value problem and consistently describe the virtual electromagnetic dressing of the initial state. In the limit of slowly evolving systems, we recover known expressions for the emission rates and work out the first correction to the static formulas in a systematic gradient expansion. Finally, we discuss the possible application of recently developed techniques in non-equilibrium quantum field theory to the problem of electromagnetic radiation. We argue, in particular, that the two-particle-irreducible (2PI) effective action formalism provides a powerful resummation scheme for the description of multiple scattering effects, such as the Landau-Pomeranchuk-Migdal suppression recently discussed in the context of equilibrium QCD.
The wave structure of monochromatic electromagnetic radiation
J. F. Nye; J. V. Hajnal
1987-01-01
The paper considers a general field of electromagnetic waves of a single frequency and identifies the salient structurally stable features of the three-dimensional pattern of polarization. The approach is geometrical rather than analytical, and it differs from previous treatments of this kind by being applicable even when the constituent plane waves are travelling in all directions. Lines and surfaces exist
Project Physics Text 4, Light and Electromagnetism.
ERIC Educational Resources Information Center
Harvard Univ., Cambridge, MA. Harvard Project Physics.
Optical and electromagnetic fundamentals are presented in this fourth unit of the Project Physics text for use by senior high students. Development of the wave theory in the first half of the 19th Century is described to deal with optical problems at the early stage. Following explanations of electric charges and forces, field concepts are
CONTINUUM ELECTROMAGNETIC RADIATION FROM SOLAR FLARES
W. A. Stein; E. P. Ney
1963-01-01
Continuum electromagnetic radiation from solar flares is discussed in ; terms of the energy loss processes of electrons in the solar atmosphere. It is ; shown that it is possible to attribute the continuum radiation both at radio ; frequencies and at visible frequencies to synchrotron radiation by exponential ; rigidity distributions of electrons. (auth);
Influence of Absorbers on the Electromagnetic Radiation
Neil V. Budko
2007-12-05
The phenomenon of the electromagnetic absorption by arbitrarily distributed discrete absorbers is analyzed from the photon point of view. It is shown that apart from the decrease in the intensity of the signal the net effect of absorption includes a relative increase in the photon bunching.
Electromagnetically driven solitons in inhomogeneous overdense plasma
A. V. Kochetov; V. A. Mironov; V. N. Bubukina; G. I. Terina
2001-01-01
In the framework of nonlinear Schrdinger equation (NSE), the dynamics of soliton excitation by an incident electromagnetic wave in an inhomogeneous overdense plasma is investigated. The periodic and chaotic regimes of the excitation are obtained, the thresholds for periodic and chaotic regimes are found. It is shown that the regimes depend on the unique parameter, which is determined by the
Electromagnetic launchers: Background and the MRL program
NASA Astrophysics Data System (ADS)
Thio, Y. C.
1982-03-01
Electromagnetic launchers are studied. These have potential applications in weaponry, controlled thermonuclear fusion, space launch, advanced industrial processes, equation of state research, generation of intense magnetic fields and as facilities for a wide range of studies in penetration mechanics, detonation, and warheads.
Electromagnetic Transducer for Hybrid Electric Vehicles
Freddy Magnussen; Chandur Sadarangani
2002-01-01
This paper describes a novel electromagnetic transducer called the Four Quadrant Transducer (4QT) for hybrid electric vehicles. The system consists of one electrical machine unit (including two rotors) and two inverters, which enable the vehicle's Internal Combustion Engine (ICE) to run at its optimum working points regarding efficiency, almost independently of the changing load requirements at the wheels. In other
Electromagnetic Composites at the Compton Scale
Frederick J. Mayer; John R. Reitz
2011-09-10
A new class of electromagnetic composite particles is proposed. The composites are very small (the Compton scale), potentially long-lived, would have unique interactions with atomic and nuclear systems, and, if they exist, could explain a number of otherwise anomalous and conflicting observations in diverse research areas.
Electromagnetic Tagging for Electronic Music Interfaces
Joseph A. Paradiso; Laurel S. Pardue; Kai-Yuh Hsiao; Ari Y. Benbasat
2003-01-01
This paper describes the development of a musical interface based on electromagnetic tagging technology, where an ensemble of passively tagged objects is identified and tracked in real time when placed in the vicinity of a reader. As the system is able to identify and update the state of many (30 or more) tags simultaneously, they can be used together in
Chaos Experiments Wave Chaos and Electromagnetic
Anlage, Steven
Dimensional Quarter Bow Tie Wave Chaotic cavity · Classical ray trajectories are chaotic - short wavelengthChaos Experiments Wave Chaos and Electromagnetic Interference in Enclosures ·Faculty: Steven M · Coupling of external radiation to computer circuits is a complex processes: apertures resonant cavities
Multifunctional composites: Healing, heating and electromagnetic integration
Thomas Anthony John Plaisted
2007-01-01
Multifunctional materials, in the context of this research, integrate other functions into materials that foremost have outstanding structural integrity. Details of the integration of electromagnetic, heating, and healing functionalities into fiber-reinforced polymer composites are presented. As a result of fiber\\/wire integration through textile braiding and weaving, the dielectric constant of a composite may be tuned from negative to positive values.
Lattice Boltzmann approaches to magnetohydrodynamics and electromagnetism
Paul Dellar
2010-01-01
J u B E g We present a lattice Boltzmann approach for magnetohydrodynamics and electromagnetism that expresses the magnetic field using a discrete set of vector distribution functions i. The i were first postulated to evolve according to a vector Boltzmann equation of the form ti+ xii.?i= - 1tau ( i- i^(0) ), where the xii are a discrete set
Analysis of Electromagnetic Phenomena in HTc Superconductors
J. Sosnowski
2008-01-01
Unique electromagnetic properties, especially concerning recent observations of the giant remanent magnetic moment in HTc superconductors, require new approach to modeling these phenomena in the oxide ceramics. The present paper is devoted to the analysis of the influence of flux pinning on critical current and flux trapping in HTc superconductors. Modeling of the interaction between nanosized pinning centers and pancake
Electromagnetic field interactions with biological systems
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.
Electromagnetic ''particle-in-cell'' plasma simulation
Langdon, A.B.
1985-04-22
''PIC'' simulation tracks particles through electromagnetic fields calculated self-consistently from the charge and current densities of the particles themselves, external sources, and boundaries. Already used extensively in plasma physics, such simulations have become useful in the design of accelerators and their r.f. sources. 5 refs.
Pullback transformation in gyrokinetic electromagnetic simulations
Mishchenko, Alexey, E-mail: alexey.mishchenko@ipp.mpg.de; Knies, 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 Alfvn 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.
Distribution of electromagnetic force in permanent magnets
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
Inverse electromagnetic scattering models for sea ice
K. M. Goldenl; D. Borup; M. Cheney; E. Cherkaeva; M. S. Dawson; Kung-Hau Ding; A. K. Fung; D. Isaacson; S. A. Johnson; Arthur K. Jordan; Jin Au Kong; Ronald Kwok; Son V. Nghiem; Robert G. Onstott; J. Sylvester; D. P. Winebrenner; I. H. H. Zabel
1998-01-01
Inverse scattering algorithms for reconstructing the physical properties of sea ice from scattered electromagnetic field data are presented. The development of these algorithms has advanced the theory of remote sensing, particularly in the microwave region, and has the potential to form the basis for a new generation of techniques for recovering sea ice properties, such as ice thickness, a parameter
Electromagnetic particle codes on unstructured grids
NASA Astrophysics Data System (ADS)
Ambrosiano, John J.; Brandon, Scott T.; Loehner, Rainald
1990-06-01
The most widely used computational model of collisionless plasmas is the Lagrangian-Eulerian hybrid technique known as particle-in-cell or PIC. In the electromagnetic version, Maxwell's equations are solved on an Eulerian grid and electromagnetic forces are interpolated from the grid to particle locations. Particles are then moved in Lagrangian fashion while their currents are interpolated back onto the grid to provide sources for the fields on the next cycle. There are many applications where one needs to model plasmas and electromagnetic waves inside regions of complicated shape. Traditional methods for solving Maxwell's equations employ finite differences on regular grids to replace differential operators. These methods are awkward for complicated boundary shapes, often replacing smoothly curved or slanted boundaries with stairsteps. The desire to incorporate realistic boundaries into plasma simulations is motivated by a host of situations in which proper representation of the boundary shape is expected to be critical. The approach to solving this problem is to design electromagnetic particle codes based on the use of unstructured grids. The arbitrary connectivity of unstructured grids provides the flexibility to place nodes wherever needed to fit the most complex boundary shapes. The most significant problems that must be addressed as a result of this strategy are grid generation, field solution, and particle tracking. The solutions to these problems, along with a few preliminary results, are presented.
Electromagnetic Wave Interactions with a Metamaterial Cloak
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
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,
Maxwell's electromagnetic theory and special relativity.
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
-59 -llc1 LIGHTNING ELECTROMAGNETIC FIELDS
Florida, University of
- 59 - llc1 LIGHTNING ELECTROMAGNETIC FIELDS: MODELING AND MEASUREMENTS V. A. Rakov University of Florida, Gainesville, FL, USA Abs&&: Modeling of lightning return strokes as sourcesof elwc fields is reviewed. Validation of the models using measured fields due to natural and triggered lightning
A Scalar Representation of Electromagnetic Fields: III
P. Roman
1959-01-01
The transformation properties of the single complex quantity, introduced by Green and Wolf to describe the electromagnetic field, are investigated and the physical energy-momentum tensor of this field is derived in terms of the scalar theory. In particular, it is found that the energy density, as defined in the previous paper, is identical with that given by the physical energy-momentum
dispersive effects in scalar-electromagnetic propagation
C. Wolf
1988-01-01
The propagation of electromagnetic waves coupled to scalar waves is shown to lead to two anomalous phenomena; firstly, a splitting or dispersive effect takes place in a background magnetic field because of the coupled oscillations; secondly, plane waves cannot propagate without two independent states of polarization.
A Scalar Representation of Electromagnetic Fields: II
E. Wolf
1959-01-01
It is shown that the scalar representation of electromagnetic fields introduced in an earlier paper leads to a new model for energy transport. The energy may be considered to be carried by two mutually incoherent scalar waves, each of which arises from contributions of circularly polarized components of the same helicity. In a monochromatic field the energy density and the
A Scalar Representation of Electromagnetic Fields : IIt
E. WOLFf
It is shown that the scalar representation of electromagnetic fields introduced in an earlier paper leads to a new model for energy transport. The energy may be considered to be carried by two mutually incoherent scalar waves, each of which arises from contributions of circularly polarized components of the same helicity. In a monochromatic field the energy density and the
Special relativity in the electromagnetic wave
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.
Scattering of Electromagnetic Waves, Theories and Applications
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
Subsurface discrimination using electromagnetic induction sensors
Thomas H. Bell; Bruce J. Barrow; Jonathan T. Miller
2001-01-01
This paper reviews the problem of subsurface discrimination using electromagnetic induction (EMI) sensors. Typically, discrimination is based on differences in the multiaxis magnetic polarizability between different objects. They review work on frequency and time domain systems, and their interrelationship. They present the results of comprehensive measurements of the multiaxis EMI response of a variety of inert ordnance items, ordnance fragments,
(Revised May 25, 2012) Electromagnetic Induction
Collins, Gary S.
(Revised May 25, 2012) Electromagnetic Induction GOALS (1) To understand what it means to have in the "induction" process precisely through words and pictures for several different cases. INTRODUCTION Magnetic that drives the flow of current around the circuit. This is simply the induction process. Lenz's Law
Electromagnetic induction spectroscopy for clearing landmines
I. J. Won; Dean A. Keiswetter; Thomas H. Bell
2001-01-01
An estimated 110 million landmines, mostly antipersonnel mines laid in over 60 countries, kill or maim over 26000 people a year. One of the dilemmas for removing landmines is the amount of false alarms in a typical minefield. Broadband electromagnetic induction spectroscopy (EMIS) is a promising technology that can both detect and identify buried objects as landmines. By reducing the
On the Laws of Electromagnetic Induction
Romano, Giovanni
2011-01-01
The Faraday-Ampere laws of electro-magnetic induction are formulated in terms of plain and twisted differential forms, taking in due account the body motion in terms of Lie time-derivatives. Covariance of Lie derivatives with respect to arbitrary relative motions, and Galilei invariance of the electro-magnetic fields, imply Galilei invariance of the induction laws, contrary to most claims in literature. A noteworthy outcome of the theory is the conclusion that the so called Lorentz force on a charged particle is not an additional law of electromagnetism, but rather, when corrected by a factor one-half, a contribution to the electric field evaluated, according to Faraday law, by an observer testing a translating charged body crossing a region of uniform magnetic field. The formulation of the laws of electromagnetism in the four dimensional classical space-time, by stating the observer-dependent splitting for bodies in motions, provides a proof of Galilei invariance of all the electric and magnetic fields invol...
(Revised May 25, 2012) Electromagnetic Induction
Collins, Gary S.
(Revised May 25, 2012) Electromagnetic Induction GOALS (1) To understand what it means to have in the "induction" process precisely through words and pictures for several different cases. INTRODUCTION Magnetic a voltage that drives the flow of current around the circuit. This is simply the induction process. Lenz
On the Laws of Electromagnetic Induction
Giovanni Romano
2012-01-14
The Faraday-Ampere laws of electro-magnetic induction are formulated in terms of plain and twisted differential forms, taking in due account the body motion in terms of Lie time-derivatives. Covariance of Lie derivatives with respect to arbitrary relative motions, and Galilei invariance of the electro-magnetic fields, imply Galilei invariance of the induction laws, contrary to most claims in literature. A noteworthy outcome of the theory is the conclusion that the so called Lorentz force on a charged particle is not an additional law of electromagnetism, but rather, when corrected by a factor one-half, a contribution to the electric field evaluated, according to Faraday law, by an observer testing a translating charged body crossing a region of uniform magnetic field. The formulation of the laws of electromagnetism in the four dimensional classical space-time, by stating the observer-dependent splitting for bodies in motions, provides a proof of Galilei invariance of all the electric and magnetic fields involved in the analysis.
Progress in Electromagnetic Launch Science and Technology
Harry D. Fair
2007-01-01
Electromagnetic (EM) launch science and technology in the United States continues to advance at a significant pace. The computational and experimental tools for understanding the critical physics issues are sufficiently mature that they are being utilized to provide insight and resolution of the remaining major technical challenges. For example, the primary computational electrodynamics code, EMAP3D, is now implemented in a
Decomposition of Electromagnetic Q and P Media
Lindell, I V
2015-01-01
Two previously studied classes of electromagnetic media, labeled as those of Q media and P media, are decomposed according to the natural decomposition introduced by Hehl and Obukhov. Six special cases based on either non-existence or sole existence of the three Hehl-Obukhov components, are defined for both medium classes.
Redirecting electromagnetic beams through wide angles
NASA Technical Reports Server (NTRS)
Dimeff, J.; Brown, R. M.; Omura, M.
1972-01-01
Electromagnetic wave enters reflector array consisting of grid work of metallic reflectors with each reflector obscuring a portion of its neighbors to prevent direct passage of wave through grid. Antenna movement involves reduced amplitude of angular motion and internal concellations of translational and rotational inertias.
NASA Technical Reports Server (NTRS)
Smith, V.; Minor, J. L. (Technical Monitor)
2000-01-01
This report documents the development of analytical techniques required for interpreting and comparing space systems electromagnetic interference test data with commercial electromagnetic interference test data using NASA Specification SSP 30237A "Space Systems Electromagnetic Emission and Susceptibility Requirements for Electromagnetic Compatibility." The PSpice computer simulation results and the laboratory measurements for the test setups under study compare well. The study results, however, indicate that the transfer function required to translate test results of one setup to another is highly dependent on cables and their actual layout in the test setup. Since cables are equipment specific and are not specified in the test standards, developing a transfer function that would cover all cable types (random, twisted, or coaxial), sizes (gauge number and length), and layouts (distance from the ground plane) is not practical.
NASA Astrophysics Data System (ADS)
Prudncio, Filipa R.; Matos, Srgio A.; Paiva, Carlos R.
2014-11-01
The concept of a perfect electromagnetic conductor (PEMC) was introduced to generalize and unify two well-known and apparently disjoint concepts in electromagnetics: the perfect electric conductor (PEC) and the perfect magnetic conductor (PMC). Although the PEMC has proven a fertile tool in electromagnetic analyses dealing with new and complex boundaries, its corresponding definition as a medium has, nevertheless, raised several problems. In fact, according to its initial 3D definition, the PEMC cannot be considered a unique and well-defined medium: it leads to extraneous fields without physical meaning. By using a previously published generalization of a PEMC that regards this concept both as a boundary and as a medium - which was dubbed an MIM (Minkowskian isotropic medium) and acts, in practice, as an actual electromagnetic conductor (EMC) - it is herein presented a straightforward analysis of waveguides containing PEMCs that readily and systematically follows from the general framework of waveguides containing EMCs.
Design and analysis of a linear type electromagnetic stirrer
S. Milind; V. Ramanarayanan
2004-01-01
Electromagnetic stirring (EMS) of metallic alloys is mainly used to refine the grain structure of castings. This technique results in increased homogeneity of the cast alloys. In this paper a design oriented approach to a linear electromagnetic stirrer is presented. A mathematical model of such a stirrer is proposed to obtain electromagnetic field solutions. The field solutions so obtained are
Electromagnetics, 26:335, 2006 Copyright Taylor & Francis Group, LLC
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
Electromagnetic characterization of PCB cards for mobile phones
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
Genetic algorithm optimization applied to electromagnetics: a review
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
Electromagnetic Field Inside the Building Due to Lightning Stroke
B. Vahidi; Sh. Farokhi
2005-01-01
The prediction of electromagnetic fields and their induced effects have become a mandatory requirement in the design phase of lightning protection systems. In the present paper authors are used NEC-2 (Numerical Electromagnetic Code) for computing electromagnetic field at different location, inside a building with 36 m height
Advances in Electromagnetic Launch Science and Technology and its Applications
H. D. Fair
2008-01-01
The US continues a broad spectrum of research to provide the scientific underpinnings for electromagnetic launch. These efforts include fundamental research on materials, properties of materials subjected to electromagnetic and thermal stress, railguns (particularly the rail-armature sliding interface), coilguns and energy storage and power conditioning. There is also broad and growing interest in novel applications of electromagnetic launch. For example,
Angular correlation function and scattering coefficient of electromagnetic waves
Zhang, Guifu
Angular correlation function and scattering coefficient of electromagnetic waves scattered We study three-dimensional (3-D) electromagnetic wave scattering from a buried object under a two-3232(98)00412-8] OCIS codes: 290.0290, 290.5880. 1. INTRODUCTION The study of electromagnetic wave scattering
TRANSMISSION AND REFLECTION OF ELECTROMAGNETIC WAVES IN RANDOMLY LAYERED MEDIA
Solna, Knut
1 TRANSMISSION AND REFLECTION OF ELECTROMAGNETIC WAVES IN RANDOMLY LAYERED MEDIA JOSSELIN GARNIER AND KNUT SLNA Abstract. In this paper the reflection of an obliquely incident electromagnetic wave, but these two angles are in general different. Key words. Electromagnetic waves, random media, homogenization
Cosmological electromagnetic fields due to gravitational wave perturbations Mattias Marklund*
Dunsby, Peter
Cosmological electromagnetic fields due to gravitational wave perturbations Mattias Marklund that the coupling between gravitational waves and a weak magnetic test field can generate electromagnetic waves. We show that this coupling leads to an initial pulse of electromagnetic waves whose width and amplitude
Second harmonic electromagnetic emission via Langmuir wave coalescence
Melrose, Don
Second harmonic electromagnetic emission via Langmuir wave coalescence A. J. Willes, P. A. Robinson 1995 The coalescence of Langmuir waves to produce electromagnetic waves at twice the plasma frequency is considered. A simplified expression for the rate of production of second harmonic electromagnetic waves
Electromagnetically induced transparency for two intense waves in plasma
Strathclyde, University of
Electromagnetically induced transparency for two intense waves in plasma B. ERSFELD and D. A electromagnetic waves in plasma is studied in order to find the conditions for induced transparency. This means transparency (EIT) means the propagation of an electromagnetic wave through an otherwise opaque medium, made
INTERACTION BETWEEN ELECTROMAGNETIC AND ELASTIC WAVES IN A BOROSILICATE GLASS
Boyer, Edmond
L-37 INTERACTION BETWEEN ELECTROMAGNETIC AND ELASTIC WAVES IN A BOROSILICATE GLASS AT LOW has been obtained of the mutual interaction of 9 GHz electromagnetic and elastic waves in a glass at 1. These experiments show the coupling of the same T.L.S. with an elastic wave and an electromagnetic wave. In our
UNIQUENESS IN INVERSE OBSTACLE SCATTERING FOR ELECTROMAGNETIC WAVES
Kress, Rainer
UNIQUENESS IN INVERSE OBSTACLE SCATTERING FOR ELECTROMAGNETIC WAVES Rainer Kress Institut f-harmonic electromagnetic waves. We will concentrate on uniqueness issues, i.e., we will investigate under what conditions to Potthast. THE INVERSE OBSTACLE SCATTERING PROBLEM The propagation of time-harmonic electromagnetic waves
Electromagnetic guided waves on linear arrays of spheres
Electromagnetic guided waves on linear arrays of spheres C M Linton, V Zalipaev, and I Thompson electromagnetic waves propagating along one-dimensional arrays of dielec- tric spheres are studied. The quasi. There have been previous studies of electromagnetic surface waves guided by periodic arrays, but these have
The structure of electromagnetic energy flows in continuous media
Franois Henrotte; Kay Hameyer
2006-01-01
A formulation of electromagnetism in continuous media is proposed that relies on the identification of the different existing electromagnetic energy reservoirs and of the flows between them. A structure is so revealed, which constitutes a natural framework to establish the partial differential equations ruling electromagnetic systems. This energy-based formulation, which unlike Maxwell's equations also integrates the material aspects, clarifies several
MATHEMATICAL MODEL OF THE INTERACTION PROBLEM BETWEEN ELECTROMAGNETIC FIELD AND
Cakoni, Fioralba
transformation. Hence the electromagnetic energy crossing the surface of the elastic body, which is not zero . Accordingly we conclude that the rate of the flow of electromagnetic energy across the surface of the elasticMATHEMATICAL MODEL OF THE INTERACTION PROBLEM BETWEEN ELECTROMAGNETIC FIELD AND ELASTIC BODY F
Cascade control strategy design for electromagnetic guidance system
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.
Electromagnetic measurements of duodenal digesta flow in cannulated sheep
Paris-Sud XI, Universit 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