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
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)
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.
Electric and magnetic fields (EMFs) are areas of energy that surround electrical devices. Everyday sources of EMFs ... phones cause cancer. They give off radio-frequency energy (RF), a form of electromagnetic radiation. Scientists need ...
NASA Technical Reports Server (NTRS)
Schafer, Charles
2000-01-01
The design and development of an Electromagnetic Propulsion is discussed. Specific Electromagnetic Propulsion Topics discussed include: (1) Technology for Pulse Inductive Thruster (PIT), to design, develop, and test of a multirepetition rate pulsed inductive thruster, Solid-State Switch Technology, and Pulse Driver Network and Architecture; (2) Flight Weight Magnet Survey, to determine/develop light weight high performance magnetic materials for potential application Advanced Space Flight Systems as these systems develop; and (3) Magnetic Flux Compression, to enable rapid/robust/reliable omni-planetary space transportation within realistic development and operational costs constraints.
Evans, J.W.; Kageyama, R.; Deepak; Cook, D.P.; Prasso, D.C.; Nishioka, S.
1995-12-31
Electromagnetic casting (EMC) is a technology that is used extensively in the aluminum industry to cast ingots with good surface finish for subsequent rolling into consumer product. The paper reviews briefly some investigations from the eighties wherein models for EMC were developed. Then more recent work is examined wherein more realistic 3D models have been developed, the traditional studies of electromagnetic and magnetohydrodynamic phenomena have been supplemented with research on heat transport, and the stability of the metal free surface has been examined. The paper concludes with three generalizations concerning modeling that may have wider applicability than EMC.
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.
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...
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.
Electromagnetic induction methods
Technology Transfer Automated Retrieval System (TEKTRAN)
Electromagnetic induction geophysical methods are finding greater and greater use for agricultural purposes. Electromagnetic induction methods measure the electrical conductivity (or resistivity) for a bulk volume of soil directly beneath the surface. An instrument called a ground conductivity meter...
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 Wave Dynamics in
Kaiser, Robin
Mesoscopic Electromagnetic Wave Dynamics in Ultracold Atomic Gases Robin Kaiser and Mark D. Havey Mesoscopic Electromagnetic Wave Dynamics in Ultracold Atomic Gases #12;39 E xperimental developments permit in the transport proper- ties of electromagnetic radiation in strongly scattering random media. Even in weakly
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 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 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.
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.
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.
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
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.
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.
"Hearing" Electromagnetic Waves
ERIC Educational Resources Information Center
Rojo, Marta; Munoz, Juan
2014-01-01
In this work, an educational experience is described in which a microwave communication link is used to make students aware that all electromagnetic waves have the same physical nature and properties. Experimental demonstrations are linked to theoretical concepts to increase comprehension of the physical principles underlying electromagnetic…
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…
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.
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)
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.
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.
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 ...
Electromagnetic rotational actuation.
Hogan, Alexander Lee
2010-08-01
There are many applications that need a meso-scale rotational actuator. These applications have been left by the wayside because of the lack of actuation at this scale. Sandia National Laboratories has many unique fabrication technologies that could be used to create an electromagnetic actuator at this scale. There are also many designs to be explored. In this internship exploration of the designs and fabrications technologies to find an inexpensive design that can be used for prototyping the electromagnetic rotational actuator.
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.
Electromagnetic properties of baryons
Ledwig, T.; Pascalutsa, V.; Vanderhaeghen, M.; Martin-Camalich, J.
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.
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 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 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.
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
Electromagnetic Radiation REFERENCE: Remote Sensing of
Gilbes, Fernando
1 CHAPTER 2: Electromagnetic Radiation Principles REFERENCE: Remote Sensing of the Environment John;2 Electromagnetic Energy Interactions Energy recorded by remote sensing systems undergoes fundamental interactions, creating convectional currents in the atmosphere. c) Electromagnetic energy in the form of electromagnetic
Differential Forms in Electromagnetics
NASA Astrophysics Data System (ADS)
Lindell, Ismo V.
2004-04-01
An introduction to multivectors, dyadics, and differential forms for electrical engineers While physicists have long applied differential forms to various areas of theoretical analysis, dyadic algebra is also the most natural language for expressing electromagnetic phenomena mathematically. George Deschamps pioneered the application of differential forms to electrical engineering but never completed his work. Now, Ismo V. Lindell, an internationally recognized authority on differential forms, provides a clear and practical introduction to replacing classical Gibbsian vector calculus with the mathematical formalism of differential forms. In Differential Forms in Electromagnetics, Lindell simplifies the notation and adds memory aids in order to ease the reader's leap from Gibbsian analysis to differential forms, and provides the algebraic tools corresponding to the dyadics of Gibbsian analysis that have long been missing from the formalism. He introduces the reader to basic EM theory and wave equations for the electromagnetic two-forms, discusses the derivation of useful identities, and explains novel ways of treating problems in general linear (bi-anisotropic) media. Clearly written and devoid of unnecessary mathematical jargon, Differential Forms in Electromagnetics helps engineers master an area of intense interest for anyone involved in research on metamaterials.
Electromagnetic wormhole vertex
NASA Astrophysics Data System (ADS)
Dowker, H. F.
1990-02-01
It is shown that wormholes cause discrete effective interactions between photons and their form is calculated. The leading term is proportional to F??F?? and hence amounts to a renormalisation of the charge of any charged field coupled to electromagnetism. It is also shown that wormholes containing two conformal scalar particles in the lowest inhomogeneous mode give an effective interaction term proportional to ? ??? ??.
Superconductive electromagnet apparatus
Mine, S.
1982-12-14
Disclosed is a superconductive electromagnet apparatus having a coil with a coiled conductor with a channel between adjacently disposed the paths of the coil conductor of which width is selected in accordance with amounts of heat produced at the corresponding portions of the coil section as viewed in cross section.
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.
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.
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.
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.
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
Electromagnetic radiation of variable frequency
Kisiel, Zbigniew
Electromagnetic radiation of variable frequency Wojciech Tadeusz Chyla, PhD Self-review of research ....................................................................................................................................... 5 PART II DISCUSSION OF THE SINGLE-TOPIC CYCLE OF PUBLICATIONS Electromagnetic radiation of variable activities #12;Wojciech Tadeusz Chyla, PhD Self-review of research activities 2/50 Electromagnetic
Electromagnetic Interrogation Techniques Damage Detection
Electromagnetic Interrogation Techniques for Damage Detection H. T. Banks and M. L. Joyner Center.P. Winfree Nasa Langley Research Center Hampton, VA Plenary Lecture, Electromagnetic Nondestructive Evaluation 2001 (ENDE 2001), Kobe, Japan, May 18-19, 20001 #12;Electromagnetic Interrogation Techniques
Electromagnetic structure of light nuclei
Saori Pastore
2015-08-28
The present understanding of nuclear electromagnetic properties including electromagnetic moments, form factors and transitions in nuclei with A $\\le$ 10 is reviewed. Emphasis is on calculations based on nuclear Hamiltonians that include two- and three-nucleon realistic potentials, along with one- and two-body electromagnetic currents derived from a chiral effective field theory with pions and nucleons.
Electromagnetic Interrogation Techniques Damage Detection
Electromagnetic Interrogation Techniques for Damage Detection H. T. Banks #3; and M. L. Joyner Wincheski and W.P. Winfree Nasa Langley Research Center Hampton, VA #3; Plenary Lecture, Electromagnetic Nondestructive Evaluation 2001 (ENDE 2001), Kobe, Japan, May 1819, 20001 #12; Electromagnetic Interrogation
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 targeting of guns
Pogue, E.W.; Boat, R.M.; Holden, D.N.; Lopez, J.R.
1996-10-01
This is the final report of a one-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). Electromagnetic pulse (EMP) signals produced from explosives being fired have been reported in the literature for fifty years. When a gun is fired it produces an EMP muzzle blast signal. The strength and nature of these signals was first analyzed in the early 1970s, while the results were interesting, no follow-up studies were conducted. With modern detection and signal processing technology, we believe that these signals could be used to instantaneously locate guns of virtually all calibers as they fire. The objective of our one-year project was to establish the basic nature of these signals and their utility in the concept of electromagnetic targeting of guns.
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.
Electromagnetically Induced Entanglement
Xihua Yang; Min Xiao
2015-05-18
We present a novel quantum phenomenon named electromagnetically induced entanglement in the conventional Lambda-type three-level atomic system driven by a strong pump field and a relatively weak probe field. Nearly perfect entanglement between the pump and probe fields can be achieved with a low coherence decay rate between the two lower levels, high pump-field intensity, and large optical depth of the atomic ensemble. The physical origin is quantum coherence between the lower doublet produced by the pump and probe fields, similar to the well-known electromagnetically induced transparency. This method would greatly facilitate the generation of nondegenerate narrow-band continuous-variable entanglement between bright light beams by using only coherent laser fields, and may find potential and broad applications in realistic quantum information processing.
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.
CMS electromagnetic calorimeter readout
Denes, P.; Wixted, R.
1997-12-31
The CMS Electromagnetic Calorimeter will consist of 109,008 crystals of Lead Tungstate (PbWO{sub 4}) arranged in a barrel (92880 crystals) and 2 endcaps (8064 crystals each). The crystals will be 25 radiation lengths long and cut in tapered shapes to make a hermetic calorimeter. The scintillation light from the crystals is captured by a photodetector, amplified and digitized. The properties of PbWO4, which is a new crystal still very much under development.
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.
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)
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, 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.
Fractional Electromagnetic Waves
J. F. Gómez; J. J. Rosales; J. J. Bernal; V. I. Tkach; M. Guía
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.
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.
Gravitation and Electromagnetism
B. G. Sidharth
2015-12-24
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.
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
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.
Electromagnetic Meissner-Effect Launcher
NASA Technical Reports Server (NTRS)
Robertson, Glen A.
1990-01-01
Proposed electromagnetic Meissner-effect launching apparatus differs from previous electromagnetic launchers; no need for electromagnet coil on projectile. Result, no need for brush contacts and high-voltage commutation equipment to supply current directly to projectile coil, or for pulse circuitry to induce current in projectile coil if brush contacts not used. Compresses magnetic field surrounding rear surface of projectile, creating gradient of magnetic pressure pushing projectile forward.
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.
Electromagnetic waves and photons
Hofmann, Ralf
2015-01-01
We explore how the thermal ground states of two mixing and pure SU(2) Yang-Mills theories, SU(2)$_{\\tiny\\mbox{CMB}}$ of scale $\\Lambda_{\\tiny\\mbox{CMB}}\\sim 10^{-4}\\,$eV and SU(2)$_{e}$ of scale $\\Lambda_{e}\\sim 5\\times 10^5\\,$eV, associate either wave or particle aspects to electromagnetic disturbances during thermalisation towards the photon gas of a blackbody, in realising the photoelectric effect, and through the frequency dependence of the monochromatic, nonthermal beam structure in Thomson/Compton scattering.
Electromagnetic waves and photons
Ralf Hofmann
2015-08-24
We explore how the thermal ground states of two mixing and pure SU(2) Yang-Mills theories, SU(2)$_{\\tiny\\mbox{CMB}}$ of scale $\\Lambda_{\\tiny\\mbox{CMB}}\\sim 10^{-4}\\,$eV and SU(2)$_{e}$ of scale $\\Lambda_{e}\\sim 5\\times 10^5\\,$eV, associate either wave or particle aspects to electromagnetic disturbances during thermalisation towards the photon gas of a blackbody, in realising the photoelectric effect, and through the frequency dependence of the monochromatic, nonthermal beam structure in Thomson/Compton scattering.
Electromagnetic levitation applications
Bayazitoglu, Y.
1996-11-01
At high temperatures, most materials react with the walls of their containers. This inevitably leads to material contamination and property degradation. Therefore, it becomes difficult to process materials to the required degree of purity and/or measure their properties at high temperatures. Levitation melting has been used on earth and microgravity since to circumvent this problem. In this paper, first a broad survey of the work done in electromagnetic levitation since its invention is given. Then the heat generation due to an alternating magnetic field is studied. Finally, the application of levitation melting in the determination of thermal diffusivity, emissivity, surface tension and viscosity of liquid metals is presented.
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.
Electromagnetically induced holographic imaging
NASA Astrophysics Data System (ADS)
Qiu, Tianhui; Xia, Lixin; Ma, Hongyang; Zheng, Chunhong; Chen, Libo
2016-01-01
The electromagnetically induced Talbot effect offers a nondestructive and lensless way to image ultracold atoms or molecules (Wen et al., 2011 [12]). In this paper, we propose another atomic imaging scheme based on the holographic imaging principle, in which three types of light source are employed as the imaging light to perform spatial interference. Compared to the previous self-imaging scheme, in the present one both the amplitude and phase information of the object can be imaged with the characteristic of arbitrarily controllable image variation in size, and the object to be imaged is no longer subject to the periodic structure.
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.
Gravitation and electromagnetism
V. P. Dmitriyev
2002-07-23
Maxwell's equations comprise both electromagnetic and gravitational fields. The transverse part of the vector potential belongs to magnetism, the longitudinal one is concerned with gravitation. The Coulomb gauge indicates that longitudinal components of the fields propagate instantaneously. The delta-function singularity of the field of the divergence of the vector potential, referred to as the dilatation center, represents an elementary agent of gravitation. Viewing a particle as a source or a scattering center of the point dilatation, the Newton's gravitation law can be reproduced.
Mathematical Tripos, Part IB : Electromagnetism 4 Electromagnetic induction
Mathematical Tripos, Part IB : Electromagnetism 4 Electromagnetic induction Recall the paragraphS, (3) then we get Faraday's Law of induction E = - d dt . (4) This will be studied now. In chapter two of induction Let C be either (a) a fixed closed geometrical curve, or (b) a physical, possibly moving circuit
Metamaterials beyond electromagnetism.
Kadic, Muamer; Bückmann, Tiemo; Schittny, Robert; Wegener, Martin
2013-12-01
Metamaterials are rationally designed man-made structures composed of functional building blocks that are densely packed into an effective (crystalline) material. While metamaterials are mostly associated with negative refractive indices and invisibility cloaking in electromagnetism or optics, the deceptively simple metamaterial concept also applies to rather different areas such as thermodynamics, classical mechanics (including elastostatics, acoustics, fluid dynamics and elastodynamics), and, in principle, also to quantum mechanics. We review the basic concepts, analogies and differences to electromagnetism, and give an overview on the current state of the art regarding theory and experiment-all from the viewpoint of an experimentalist. This review includes homogeneous metamaterials as well as intentionally inhomogeneous metamaterial architectures designed by coordinate-transformation-based approaches analogous to transformation optics. Examples are laminates, transient thermal cloaks, thermal concentrators and inverters, 'space-coiling' metamaterials, anisotropic acoustic metamaterials, acoustic free-space and carpet cloaks, cloaks for gravitational surface waves, auxetic mechanical metamaterials, pentamode metamaterials ('meta-liquids'), mechanical metamaterials with negative dynamic mass density, negative dynamic bulk modulus, or negative phase velocity, seismic metamaterials, cloaks for flexural waves in thin plates and three-dimensional elastostatic cloaks. PMID:24190877
Electromagnetic Field Penetration Studies
NASA Technical Reports Server (NTRS)
Deshpande, M.D.
2000-01-01
A numerical method is presented to determine electromagnetic shielding effectiveness of rectangular enclosure with apertures on its wall used for input and output connections, control panels, visual-access windows, ventilation panels, etc. Expressing EM fields in terms of cavity Green's function inside the enclosure and the free space Green's function outside the enclosure, integral equations with aperture tangential electric fields as unknown variables are obtained by enforcing the continuity of tangential electric and magnetic fields across the apertures. Using the Method of Moments, the integral equations are solved for unknown aperture fields. From these aperture fields, the EM field inside a rectangular enclosure due to external electromagnetic sources are determined. Numerical results on electric field shielding of a rectangular cavity with a thin rectangular slot obtained using the present method are compared with the results obtained using simple transmission line technique for code validation. The present technique is applied to determine field penetration inside a Boeing-757 by approximating its passenger cabin as a rectangular cavity filled with a homogeneous medium and its passenger windows by rectangular apertures. Preliminary results for, two windows, one on each side of fuselage were considered. Numerical results for Boeing-757 at frequencies 26 MHz, 171-175 MHz, and 428-432 MHz are presented.
Electromagnetically Induced Entanglement
NASA Astrophysics Data System (ADS)
Yang, Xihua; Xiao, Min
2015-08-01
Quantum entanglement provides an essential resource for quantum computation, quantum communication, and quantum network. How to conveniently and efficiently produce entanglement between bright light beams presents a challenging task to build realistic quantum information processing networks. Here, we present an efficient and convenient way to realize a novel quantum phenomenon, named electromagnetically induced entanglement, in the conventional ?-type three-level atomic system driven by a strong pump field and a relatively weak probe field. Nearly perfect entanglement between the two fields can be achieved with a low coherence decay rate between the two lower levels, high pump-field intensity, and large optical depth of the atomic ensemble. The physical origin is quantum coherence between the lower doublet produced by the pump and probe fields, similar to the well-known electromagnetically induced transparency. This method would greatly facilitate the generation of nondegenerate narrow-band continuous-variable entanglement between bright light beams by using only coherent laser fields, and may find potential and broad applications in realistic quantum information processing.
Electromagnetically Induced Entanglement.
Yang, Xihua; Xiao, Min
2015-01-01
Quantum entanglement provides an essential resource for quantum computation, quantum communication, and quantum network. How to conveniently and efficiently produce entanglement between bright light beams presents a challenging task to build realistic quantum information processing networks. Here, we present an efficient and convenient way to realize a novel quantum phenomenon, named electromagnetically induced entanglement, in the conventional ?-type three-level atomic system driven by a strong pump field and a relatively weak probe field. Nearly perfect entanglement between the two fields can be achieved with a low coherence decay rate between the two lower levels, high pump-field intensity, and large optical depth of the atomic ensemble. The physical origin is quantum coherence between the lower doublet produced by the pump and probe fields, similar to the well-known electromagnetically induced transparency. This method would greatly facilitate the generation of nondegenerate narrow-band continuous-variable entanglement between bright light beams by using only coherent laser fields, and may find potential and broad applications in realistic quantum information processing. PMID:26314514
Electromagnetically Induced Entanglement
Yang, Xihua; Xiao, Min
2015-01-01
Quantum entanglement provides an essential resource for quantum computation, quantum communication, and quantum network. How to conveniently and efficiently produce entanglement between bright light beams presents a challenging task to build realistic quantum information processing networks. Here, we present an efficient and convenient way to realize a novel quantum phenomenon, named electromagnetically induced entanglement, in the conventional ?-type three-level atomic system driven by a strong pump field and a relatively weak probe field. Nearly perfect entanglement between the two fields can be achieved with a low coherence decay rate between the two lower levels, high pump-field intensity, and large optical depth of the atomic ensemble. The physical origin is quantum coherence between the lower doublet produced by the pump and probe fields, similar to the well-known electromagnetically induced transparency. This method would greatly facilitate the generation of nondegenerate narrow-band continuous-variable entanglement between bright light beams by using only coherent laser fields, and may find potential and broad applications in realistic quantum information processing. PMID:26314514
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.
Elec Eng 2FH3 Electromagnetics I
Haykin, Simon
Elec Eng 2FH3 Electromagnetics I 2014/15 Term 2 Dr. Natalia K-Gomba Email: dorngoml@mcmaster.ca Office: MARC Calendar Description: Electromagnetics Part I is an introduction into engineering electromagnetics. It covers
Electromagnetic Characterization of MIMO Communication Systems
Heath Jr., - Robert W.
Electromagnetic Characterization of MIMO Communication Systems Kapil R. Dandekar, Sumant Kawale electromagnetic interactions between the antenna arrays and the environment. To dissect the influence of various electromagnetic phenomena on the total MIMO communication channel, in this paper a hybrid computational
Electromagnetic direct implicit PIC simulation
Langdon, A.B.
1983-03-29
Interesting modelling of intense electron flow has been done with implicit particle-in-cell simulation codes. In this report, the direct implicit PIC simulation approach is applied to simulations that include full electromagnetic fields. The resulting algorithm offers advantages relative to moment implicit electromagnetic algorithms and may help in our quest for robust and simpler implicit codes.
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…
Electromagnetics laboratory annual report, 1994
NASA Astrophysics Data System (ADS)
Lindell, I. V.; Sihvola, A. H.
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.
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.
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.
Electromagnetic inverse scattering
NASA Technical Reports Server (NTRS)
Bojarski, N. N.
1972-01-01
A three-dimensional electromagnetic inverse scattering identity, based on the physical optics approximation, is developed for the monostatic scattered far field cross section of perfect conductors. Uniqueness of this inverse identity is proven. This identity requires complete scattering information for all frequencies and aspect angles. A nonsingular integral equation is developed for the arbitrary case of incomplete frequence and/or aspect angle scattering information. A general closed-form solution to this integral equation is developed, which yields the shape of the scatterer from such incomplete information. A specific practical radar solution is presented. The resolution of this solution is developed, yielding short-pulse target resolution radar system parameter equations. The special cases of two- and one-dimensional inverse scattering and the special case of a priori knowledge of scatterer symmetry are treated in some detail. The merits of this solution over the conventional radar imaging technique are discussed.
Electromagnetic induction launchers
NASA Astrophysics Data System (ADS)
Driga, M. D.; Weldon, W. F.; Woodson, H. H.
1986-11-01
Design features and potential applications of an electromagnetic induction launcher (EIL) and its power source, a rising frequency generator (RFG), are described. The RFG permits integration of the power supply/accelerator system design, with the generator voltage, frequency, rotor and stator inertias and initial velocities matched to the coaxial accelerator requirements. Analytical models are defined for short and long rotor variants of the RFG, for the accelerated traveling fields of an EIL, and for the projectile design. Conceptual designs are discussed for a coaxial EIL capable of accelerating a 1 kg projectile to 10 km/sec at a continuous 250,000 g acceleration and for an aircraft launcher which could impart a continuous 5 g acceleration to an 18,000 lb load.
Electromagnetically induced invisibility cloaking
Darran F. Milne; Natalia Korolkova
2012-06-18
Invisibility cloaking imposes strict conditions on the refractive index profiles of cloaking media that must be satisfied to successfully hide an object. The first experimental demonstrations of cloaking used artificial metamaterials to respond to this challenge. In this work we show how a much simpler technique of electromagnetically induced transparency can be used to achieve a partial, {\\it carpet} cloaking at optical frequencies in atomic vapours or solids. To generate a desired combination of low absorption with strong modifications of the refractive index, we use chiral media with an induced magneto-electrical cross-coupling. We demonstrate that high-contrast positive refractive indices can be attained by fine tuning the material with a gradient magnetic field and calculate the parameters required to construct a carpet cloak.
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.
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.
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.
Causal electromagnetic interaction equations
Zinoviev, Yury M.
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.
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.
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) have been developed for application to auxiliary and primary spacecraft propulsion. Both the PPT and MPD thrusters have been flown in space, though only PPTs have been used on operational satellites. The performance of operational PPTs is quite poor, providing only about 8 percent efficiency at about 1000 sec specific impulse. Laboratory PPTs yielding 34 percent efficiency at 5170 sec specific impulse have been demonstrated. Laboratory MPD thrusters have been demonstrated with up to 70 percent efficiency and 7000 sec specific impulse. Recent PIT performance measurements using ammonia and hydrazine propellants are extremely encouraging, reaching 50 percent efficiency for specific impulses between 4000 and 8000 sec.
ELECTROMAGNETIC FIELD EFFECTS IN EXPLOSIVES
Tasker, D. G.; Whitley, V. H.; Lee, R. J.
2009-12-28
Present and previous research on the effects of electromagnetic fields on the initiation and detonation of explosives and the electromagnetic properties of explosives are reviewed. Among the topics related to detonating explosives are: enhancement of performance; and control of initiation and growth of reaction. Two series of experiments were performed to determine the effects of 1-T magnetic fields on explosive initiation and growth in the modified gap test and on the propagation of explosively generated plasma into air. The results have implications for the control of reactions in explosives and for the use of electromagnetic particle velocity gauges.
Electromagnetic neutrinos in laboratory experiments and astrophysics
Carlo Giunti; Konstantin A. Kouzakov; Yu-Feng Li; Alexey V. Lokhov; Alexander I. Studenikin; Shun Zhou
2015-11-12
An overview of neutrino electromagnetic properties, which open a door to the new physics beyond the Standard Model, is given. The effects of neutrino electromagnetic interactions both in terrestrial experiments and in astrophysical environments are discussed. The experimental bounds on neutrino electromagnetic characteristics are summarized. Future astrophysical probes of electromagnetic neutrinos are outlined.
Electromagnetic recording and playback device
Chavez, Dylan, 1981-
2004-01-01
The purpose of this thesis is the design and manufacture of an electromagnetic recording and playback device. The device was designed to record information onto a steel wire which can replay the signal. The device is of ...
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 Wormholes via Handlebody Constructions
NASA Astrophysics Data System (ADS)
Greenleaf, Allan; Kurylev, Yaroslav; Lassas, Matti; Uhlmann, Gunther
2008-07-01
Cloaking devices are prescriptions of electrostatic, optical or electromagnetic parameter fields (conductivity {?(x)} , index of refraction n( x), or electric permittivity {?(x)} and magnetic permeability {?(x)}) which are piecewise smooth on {mathbb{R}^3} and singular on a hypersurface {?} , and such that objects in the region enclosed by {?} are not detectable to external observation by waves. Here, we give related constructions of invisible tunnels, which allow electromagnetic waves to pass between possibly distant points, but with only the ends of the tunnels visible to electromagnetic imaging. Effectively, these change the topology of space with respect to solutions of Maxwell’s equations, corresponding to attaching a handlebody to {mathbb{R}^3} . The resulting devices thus function as electromagnetic wormholes.
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.
Seismo-Electromagnetic Study in China
NASA Astrophysics Data System (ADS)
Huang, Qinghua
In this paper, I made a brief review on the earthquake-related electromagnetic study in China, especially focusing on geo-electromagnetic observation and empirical prediction based on the observation data. After introducing briefly the roles of China Earthquake Administration (CEA) in seismo-electromagnetic study in China, I summarized various electromagnetic observations (e.g., apparent resistivity, geoelectric potential, geomagnetic field, electromagnetic disturbance, etc.). As the potential application, I showed the cases of the empirical prediction based on the observed electromagnetic data associated with some earthquakes in China. This paper may provide some useful information for those who want to know the general situation of seismo-electromagnetic study in China.
Electromagnetic production of hypernuclei
B. I. S. van der Ventel; T. Mart; H. -F. Lu; H. L. Yadav; G. C. Hillhouse
2011-02-14
A formalism for the electromagnetic production of hypernuclei is developed where the cross section is written as a contraction between a leptonic tensor and a hadronic tensor. The hadronic tensor is written in a model-independent way by expanding it in terms of a set of five nuclear structure functions. These structure functions are calculated by assuming that the virtual photon interacts with only one bound nucleon. We use the most recent model for the elementary current operator which gives a good description of the experimental data for the corresponding elementary process. The bound state wave functions for the bound nucleon and hyperon are calculated within a relativistic mean-field model. We calculate the unpolarized triple differential cross section for the hypernuclear production process e + 12C --> e + K+ + 12_Lambda{B} as a function of the kaon scattering angle. The nuclear structure functions are calculated within a particle-hole model. The cross section displays a characteristic form of being large for small values of the kaon scattering angle with a smooth fall-off to zero with increasing angle. The shape of the cross section is essentially determined by the nuclear structure functions. In addition, it is found that for the unpolarized triple differential cross section one structure function is negligible over the entire range of the kaon scattering angle.
Athanasios Bakopoulos; Panagiota Kanti
2014-05-18
In the first part of the present work, we focus on the theory of gravitoelectromagnetism (GEM), and we derive the full set of equations and constraints that the GEM scalar and vector potentials ought to satisfy. We discuss important aspects of the theory, such as the presence of additional constraints resulting from the field equations and gauge condition, the requirement of the time-independence of the vector potential and the emergence of additional terms in the expression of the Lorentz force. We also propose an alternative ansatz for the metric perturbations that is found to be compatible only with a vacuum configuration but evades several of the aforementioned obstacles. In the second part of this work, we pose the question of whether a tensorial theory using the formalism of General Relativity could re-produce the theory of Electromagnetism. We demonstrate that the full set of Maxwell's equations can be exactly re-produced for a large class of models, but the framework has several weak points common with those found in GEM.
Electromagnetic Launch to Space
NASA Astrophysics Data System (ADS)
McNab, I. R.
Many advances in electromagnetic (EM) propulsion technology have occurred in recent years. Linear motor technology for low-velocity and high-mass applications is being developed for naval catapults. Such technology could serve as the basis for a first-stage booster launch--as suggested by the US National Aeronautics and Space Administration (NASA) in the Maglifter concept. Using railguns, laboratory experiments have demonstrated launch velocities of 2-3 km/s and muzzle energies > 8 MJ. The extension of this technology to the muzzle velocities ( 7500 m/s) and energies ( 10 GJ) needed for the direct launch of payloads into orbit is very challenging but may not be impossible. For launch to orbit, even long launchers (> 1000 m) would need to operate at accelerations > 1000 G to reach the required velocities, so it would only be possible to launch rugged payloads, such as fuel, water, and materiel. Interest is being shown in such concepts by US, European, Russian, and Chinese researchers. An intermediate step proposed in France could be to launch payloads to sounding rocket altitudes for ionospheric research.
Electromagnetically driven peristaltic pump
Marshall, Douglas W. (Blackfoot, ID)
2000-01-01
An electromagnetic peristaltic pump apparatus may comprise a main body section having an inlet end and an outlet end and a flexible membrane which divides the main body section into a first cavity and a second cavity. The first cavity is in fluid communication with the inlet and outlet ends of the main body section. The second cavity is not in fluid communication with the first cavity and contains an electrically conductive fluid. The second cavity includes a plurality of electrodes which are positioned within the second cavity generally adjacent the flexible membrane. A magnetic field generator produces a magnetic field having a plurality of flux lines at least some of which are contained within the second cavity of the main body section and which are oriented generally parallel to a flow direction in which a material flows between the inlet and outlet ends of the main body section. A control system selectively places a voltage potential across selected ones of the plurality of electrodes to deflect the flexible membrane in a wave-like manner to move material contained in the first cavity between the inlet and outlet ends of the main body section.
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.
Pulsed electromagnetic gas acceleration
NASA Technical Reports Server (NTRS)
Jahn, R. G.; Vonjaskowsky, W. F.; Clark, K. E.
1974-01-01
Detailed measurements of the axial velocity profile and electromagnetic structure of a high power, quasi-steady MPD discharge are used to formulate a gasdynamic model of the acceleration process. Conceptually dividing the accelerated plasma into an inner flow and an outer flow, it is found that more than two-thirds of the total power in the plasma is deposited in the inner flow, accelerating it to an exhaust velocity of 12.5 km/sec. The outer flow, which is accelerated to a velocity of only 6.2 km/sec, appears to provide a current conduction path between the inner flow and the anode. Related cathode studies have shown that the critical current for the onset of terminal voltage fluctuations, which was recently shown to be a function of the cathode area, appears to reach an asymptote for cathodes of very large surface area. Detailed floating potential measurements show that the fluctuations are confined to the vicinity of the cathode and hence reflect a cathode emission process rather than a fundamental limit on MPD performance.
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.
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.
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.
Information Security due to Electromagnetic Environments
NASA Astrophysics Data System (ADS)
Sekiguchi, Hidenori; Seto, Shinji
Generally, active electronic devices emit slightly unintentional electromagnetic noise. From long ago, electromagnetic emission levels have been regulated from the aspect of electromagnetic compatibility (EMC). Also, it has been known the electromagnetic emissions have been generated from the ON/OFF of signals in the device. Recently, it becomes a topic of conversation on the information security that the ON/OFF on a desired signal in the device can be reproduced or guessed by receiving the electromagnetic emission. For an example, a display image on a personal computer (PC) can be reconstructed by receiving and analyzing the electromagnetic emission. In sum, this fact makes known information leakage due to electromagnetic emission. “TEMPEST" that has been known as a code name originated in the U. S. Department of Defense is to prevent the information leakage caused by electromagnetic emissions. This paper reports the brief summary of the information security due to electromagnetic emissions from information technology equipments.
Binary black holes' effects on electromagnetic fields.
Palenzuela, Carlos; Anderson, Matthew; Lehner, Luis; Liebling, Steven L; Neilsen, David
2009-08-21
In addition to producing gravitational waves, the dynamics of a binary black hole system could induce emission of electromagnetic radiation by affecting the behavior of plasmas and electromagnetic fields in their vicinity. We here study how the electromagnetic fields are affected by a pair of orbiting black holes through the merger. In particular, we show how the binary's dynamics induce a variability in possible electromagnetically induced emissions as well as a possible enhancement of electromagnetic fields during the late-merge and merger epochs. These time dependent features will likely leave their imprint in processes generating detectable emissions and can be exploited in the detection of electromagnetic counterparts of gravitational waves. PMID:19792706
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
Holographic Estimate of Electromagnetic Mass
Deog Ki Hong
2015-08-14
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 $0.48~{\\rm MeV}$ larger than that of neutron, which is in agreement with recent lattice results. Similarly for pions we obtain $m_{\\pi^{\\pm}}-m_{\\pi^0}=1.8~{\\rm MeV}$, roughly half of the experimental value. The electromagnetic mass of pions is found to be independent of $N_c$ and 't Hooft coupling and its scale is set only by the Kaluza-Klein scale of the model, $M_{\\rm KK}=949~{\\rm MeV}$.
Electromagnetic corrections to baryon masses
Durand, Loyal; Ha, Phuoc
2005-04-01
We analyze the electromagnetic contributions to the octet and decuplet baryon masses using the heavy-baryon approximation in chiral effective field theory and methods we developed in earlier analyses of the baryon masses and magnetic moments. Our methods connect simply to Morpurgo's general parametrization of the electromagnetic contributions and to semirelativistic quark models. Our calculations are carried out including the one-loop mesonic corrections to the basic electromagnetic interactions, so to two loops overall. We find that to this order in the chiral loop expansion there are no three-body contributions. The Coleman-Glashow relation and other sum rules derived in quark models with only two-body terms therefore continue to hold, and violations involve at least three-loop processes and can be expected to be quite small. We present the complete formal results and some estimates of the matrix elements here. Numerical calculations will be presented separately.
Un-renormalized classical electromagnetism
Ibison, Michael . 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 Models of Extragalactic Jets
Lisanti, M.; Blandford, R.; /KIPAC, Menlo Park
2007-10-22
Relativistic jets may be confined by large-scale, anisotropic electromagnetic stresses that balance isotropic particle pressure and disordered magnetic field. A class of axisymmetric equilibrium jet models will be described and their radiative properties outlined under simple assumptions. The partition of the jet power between electromagnetic and mechanical forms and the comoving energy density between particles and magnetic field will be discussed. Current carrying jets may be recognized by their polarization patterns. Progress and prospects for measuring this using VLBI and GLAST observations will be summarized.
Handbook of electromagnetic pump technology
Baker, R.S.; Tessier, M.J.
1987-01-01
The Handbook of Electromagnetic Pump Technology features: Step-by-Step design procedures, relating to actual pumps for specific applications; Computer program listings for pump efficiency and weight prediction (in BASIC); Test results for selected pump applications; Practical considerations, installation and implementation; A discussion of the related use of electromagnetic devices in magnetohydrodynamic power generation. A source of information for EM pump design and selection, the Handbook is designed for metallurgical and plant engineers in the metals industry, design engineers in chemical and process plants, and students of electrical, mechanical, metallurgical, and nuclear engineering.
Physiologic regulation in electromagnetic fields
Michaelson, S.M.
1982-01-01
Electromagnetic fields have been demonstrated to elicit thermoregulatory responses, neuroendocrine, neurochemical modulations, and behavioral reactions. These physiologic regulatory processes are exquisitely tuned, interrelated functions that constitute sensitive indicators of organismic responses to radiofrequency energy absorption (the radiofrequency portion of the electromagnetic spectrum includes as one part microwaves). Assessment of the integration and correlation of these functions relative to the thermal inputs and homeokinetic reactions of the individual subjected to radiofrequency energy should permit differentiation between potential hazards that might compromise the individual's ability to maintain normal physiologic function and effects that are compensated by physiologic redundancy.
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 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.
Bathymetry, electromagnetic streamlines and the marine controlled source electromagnetic method
NASA Astrophysics Data System (ADS)
Pethick, Andrew
2014-07-01
Seafloor topography must influence the strength and direction of electromagnetic fields generated during deep ocean controlled source electromagnetic surveying. Neither mathematical equation nor rules of thumb provide a clear perspective of how changes in water column thickness alters electromagnetic fields that engulf hundreds of cubic kilometres of air, ocean, host and reservoir. We use streamline visualisation to provide a generalised representation of how electromagnetic fields propagate into a 2D geo-electrical setting that includes strong bathymetry. Of particular interest are: (i)' dead zones' where electric fields at the ocean floor are demonstrated to be weak and (ii) the 'airwave' that appears in the electric field streamlines as circulating vortices with a shape that is clearly influenced by changes in ocean depth. Our analysis of the distribution of electric fields for deep and shallow water examples alludes to potential benefits from placement of receivers and/or transmitters higher in the water column as is the case for towed receiver geometries. Real-time streamline representation probably holds the most value at the survey planning stage, especially for shallow water marine EM surveys where ocean bottom topography is likely to be consequential.
A Class of Stationary Electromagnetic Vacuum Fields
Israel, Werner; Wilson, Gordon A.
1972-01-10
It is shown how a new class of stationary electromagnetic vacuum fields can be generated from solutions of Laplace's equation. These fields are a stationary generalization of the static electromagnetic vacuum fields of Weyl, Majumdar, and Papapetrou...
ECGR3142 Electromagnetic Devices Course Description
Nasipuri, Asis
ECGR3142 Electromagnetic Devices Course Description Principles of operation and basic design (Introduction to Electromagnetic Fields) with a grade of C or better Course Textbook Slemon G. R., Electric, steady-state performance, motor operation, generator operation. Induction machines: sinusoidally
SOME APPROXIMATE METHODS FOR COMPUTING ELECTROMAGNETIC FIELDS
Torresani, Bruno
SOME APPROXIMATE METHODS FOR COMPUTING ELECTROMAGNETIC FIELDS SCATTERED BY COMPLEX OBJECTS P discuss several approximate methods for computing electromagnetic scattering by objects of complex shape. Dependingon the relative size of the scatterer compared to the incident wavelength, different techniques have
Electromagnetically Restrained Lithium Blanket APEX Interim Report November, 1999
California at Los Angeles, University of
Electromagnetically Restrained Lithium Blanket APEX Interim Report November, 1999 6-1 CHAPTER 6: ELECTROMAGNETICALLY RESTRAINED LITHIUM BLANKET Contributors Robert Woolley #12;Electromagnetically Restrained Lithium Blanket APEX Interim Report November, 1999 6-2 6. ELECTROMAGNETICALLY RESTRAINED LITHIUM BLANKET 6
Electromagnetic effects on geodesic acoustic modes
Bashir, M. F.; Smolyakov, A. I.; Elfimov, A. G.; Melnikov, A. V.; Murtaza, G.
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.
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
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
The courts and electromagnetic fields
Freeman, M. )
1990-07-19
This article examines the recent development in eminent domain cases involving power transmission line rights of way, the issue of fear of the mythical buyer. The author feels that the fear of electrocution or of the possible cancer-inducing effects of electromagnetic fields is greatly influencing court decisions in these cases. The results could be more expensive rights of way acquisition by utilities.
Electromagnetic Couplings of Nucleon Resonances
T. Feuster; U. Mosel
1996-07-16
An effective Lagrangian calculation of pion photoproduction including all nucleon resonances up to $\\sqrt s = 1.7$ GeV is presented. We compare our results to recent calculations and show the influence of different width parametrizations and offshell cutoffs on the photoproduction multipoles. We determine the electromagnetic couplings of the resonances from a new fit to the multipole data.
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.
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…
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 pulses bone healing booster
NASA Astrophysics Data System (ADS)
Sintea, S. R.; Pomazan, V. M.; Bica, D.; Grebenisan, D.; Bordea, N.
2015-11-01
Posttraumatic bone restoration triggered by the need to assist and stimulate compensatory bone growth in periodontal condition. Recent studies state that specific electromagnetic stimulation can boost the bone restoration, reaching up to 30% decrease in recovery time. Based on the existing data on the electromagnetic parameters, a digital electronic device is proposed for intra oral mounting and bone restoration stimulation in periodontal condition. The electrical signal is applied to an inductive mark that will create and impregnate magnetic field in diseased tissue. The device also monitors the status of the electromagnetic field. Controlled wave forms and pulse frequency signal at programmable intervals are obtained with optimized number of components and miniaturized using surface mounting devices (SMD) circuits and surface mounting technology (SMT), with enhanced protection against abnormal current growth, given the intra-oral environment. The system is powered by an autonomous power supply (battery), to limit the problems caused by powering medical equipment from the main power supply. Currently the device is used in clinical testing, in cycles of six up to twelve months. Basic principles for the electrical scheme and algorithms for pulse generation, pulse control, electromagnetic field control and automation of current monitoring are presented, together with the friendly user interface, suitable for medical data and patient monitoring.
Computational design for electromagnetic simulations
NASA Astrophysics Data System (ADS)
Glasby, Ryan Steven
An automatic computational procedure has been developed to efficiently and accurately design the shape of complicated electromagnetic objects. These electromagnetic objects can be simulated for operation at high frequencies (˜10 GHz), and can be comprised of dissimilar materials. The automated design procedure consists of linking together an original electromagnetic field simulation tool, an original adjoint routine for obtaining sensitivity derivatives, and an original grid-smoothing tool with an existing optimization package. The electromagnetic field simulation software employs a temporally and spatially higher-order accurate Streamline Upwind/Petrov-Galerkin finite-element method that numerically solves Maxwell's equations in the time domain using implicit time stepping. The software for computing sensitivity derivatives employs a reverse-mode time-accurate discrete adjoint methodology that is formulated to automatically maintain consistency with the electromagnetic field simulation software. Grid smoothing is achieved using a spatially higher-order accurate Galerkin finite-element method that generates a numerical solution to the linear elastic equations. All computational solutions to the linear systems present in each software tool are obtained using the Generalized Minimum Residual algorithm with block diagonal preconditioning. Each software tool is implemented using a parallel processing paradigm and is therefore capable of being executed on a distributed memory supercomputer. The order of accuracy of the electromagnetic field simulation software has been determined by using comparisons with exact solutions. The field software's results were compared to the exact solution of a rectangular resonant cavity. In all cases, the order properties of the field software exceed theoretical expectations when linear, quadratic, and cubic tetrahedral elements are employed to discretize the field. To demonstrate the consistency of the adjoint-based sensitivity derivates with those obtained directly from the field solver, derivatives have been extracted from the field software using a complex variable technique. The sensitivity derivatives from the reverse-mode time-accurate discrete adjoint method were then compared and demonstrated to agree to at least seven decimal places. As a demonstration of the assembled technologies, the optimization procedure successfully and efficiently modified the shape of two electromagnetic objects to reduce a specified cost function. A dielectric cube, under the influence of a propagating plane wave, was repositioned within a larger free space volume so that the field variables on the surface of the cube match desired values at a specified time. A similar demonstration case has also been conducted to modify the shape of a dielectric ellipsoid, under the same conditions as the cube.
Some Student Conceptions of Electromagnetic Induction
ERIC Educational Resources Information Center
Thong, Wai Meng; Gunstone, Richard
2008-01-01
Introductory electromagnetism is a central part of undergraduate physics. Although there has been some research into student conceptions of electromagnetism, studies have been sparse and separated. This study sought to explore second year physics students' conceptions of electromagnetism, to investigate to what extent the results from the present…
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
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 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
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
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
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
Electromagnetic Field Theory Fall 2014 Course Outline
Haimovich, Alexander
ECE 620 Electromagnetic Field Theory Fall 2014 Course Outline Instructor: Dr. Gerald Whitman Text: Constantine Balanis, Advanced Engineering Electromagnetics, 2nd ed., Wiley, 2012; ISBN:978-0- 470-58948-9 Reference: Roger Harrington, Time-Harmonic Electromagnetic Fields, , Wiley-IEEE Press 2001; ISBN:978
611: Electromagnetic Theory Problem Sheet 6
Pope, Christopher
611: Electromagnetic Theory Problem Sheet 6 (1) A small test particle (mass m and positive charge q of the orbit. (2a) Consider an electromagnetic wave for which the electric field is given by E = E0 sin t (sin in (2a) and (2b) for an electromagnetic wave for which the electric field is E = E0 cos z (cos t, - sin
Electromagnetics from Simulation to Optimal Design
Grohs, Philipp
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 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 7
Pope, Christopher
611: Electromagnetic Theory Problem Sheet 7 (1) Consider the non-relativistic motion of a particle momentum of the particle about the centre of the force at r = 0.) (2a) Consider an electromagnetic wave the energy density and the Poynting vector. (2c) Repeat the steps in (2a) and (2b) for an electromagnetic
Solar/Electromagnetic Energy Harvesting and Wireless
Tentzeris, Manos
INVITED P A P E R Solar/Electromagnetic Energy Harvesting and Wireless Power Transmission This paper reviews numerous existing efforts and solutions in the field of solar and electromagnetic energy of solar/electromagnetic energy harvest- ing and wireless power transmission. More specifically, the paper
Strong permanent magnet-assisted electromagnetic undulator
Halbach, Klaus
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.
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 moments of quasistable particle
Ledwig, Tim; Pascalutsa, Vladimir; Vanderhaeghen, Marc
2010-11-01
We deal with the problem of assigning electromagnetic moments to a quasistable particle (i.e., a particle with mass located at the particle's decay threshold). In this case, an application of a small external electromagnetic field changes the energy in a nonanalytic way, which makes it difficult to assign definitive moments. On the example of a spin-1/2 field with mass M{sub *} interacting with two fields of masses M and m, we show how a conventionally defined magnetic dipole moment diverges at M{sub *}=M+m. We then show that the conventional definition makes sense only when the values of the applied magnetic field B satisfy |eB|/2M{sub *}<<|M{sub *}-M-m|. We discuss implications of these results to existing studies in electroweak theory, chiral effective-field theory, and lattice QCD.
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.
Electromagnetically controlled multiferroic thermal diode
NASA Astrophysics Data System (ADS)
Chotorlishvili, L.; Etesami, S. R.; Berakdar, J.; Khomeriki, R.; Ren, Jie
2015-10-01
We propose an electromagnetically tunable thermal diode based on a two-phase multiferroic composite. Analytical and full numerical calculations for a prototypical heterojunction composed of iron on barium titanate in the tetragonal phase demonstrate a strong heat rectification effect that can be controlled externally by a moderate electric field. This finding is important for thermally based information processing and sensing and can also be integrated in (spin) electronic circuits for heat management and recycling.
electromagnetics, eddy current, computer codes
Energy Science and Technology Software Center (ESTSC)
2002-03-12
TORO Version 4 is designed for finite element analysis of steady, transient and time-harmonic, multi-dimensional, quasi-static problems in electromagnetics. The code allows simulation of electrostatic fields, steady current flows, magnetostatics and eddy current problems in plane or axisymmetric, two-dimensional geometries. TORO is easily coupled to heat conduction and solid mechanics codes to allow multi-physics simulations to be performed.
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.
Electromagnetic brake/clutch device
NASA Technical Reports Server (NTRS)
Vranish, John M. (inventor)
1994-01-01
An electromagnetic brake/clutch device includes a drive shaft supported by at least one bearing for transmitting torque, a housing, affixed to prevent its rotation, surrounding the drive shaft, and an electromagnetically activated device within the housing to selectively prevent and allow rotation of the drive shaft. The electromagnetically activated device includes a plurality of cammed rollers to prevent counter-clockwise rotation of the drive shaft. The drive shaft includes a circumferential disk and the housing includes a reaction ring for engagement with the plurality of cammed rollers. The plurality of cammed rollers are released from engagement with the circumferential disk and the reaction ring by a plurality of tripping mechanisms within the housing. The tripping action uses the locking force to act as a release force merely by changing the boundary conditions of the roller interface angles. The tripping mechanisms include trippers for disengaging the plurality of cammed rollers and an anvil shaped portion for providing lateral movement of the trippers. The plurality of cammed rollers is preloaded to engagement with the circumferential disk and reaction ring by a spring, and is located with respect to an adjacent tripping mechanism with another spring.
Palenzuela, Carlos; Lehner, Luis; Yoshida, Shin
2010-04-15
In addition to producing loud gravitational waves, the dynamics of a binary black hole system could induce emission of electromagnetic radiation by affecting the behavior of plasmas and electromagnetic fields in their vicinity. We study how the electromagnetic fields are affected by a pair of orbiting black holes through the merger. In particular, we show how the binary's dynamics induce a variability in possible electromagnetically induced emissions as well as an enhancement of electromagnetic fields during the late-merge and merger epochs. These time dependent features will likely leave their imprint in processes generating detectable emissions and can be exploited in the detection of electromagnetic counterparts of gravitational waves.
Electromagnetic 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.
Anisotropic conducting films for electromagnetic radiation applications
Cavallo, Francesca; Lagally, Max G.; Rojas-Delgado, Richard
2015-06-16
Electronic devices for the generation of electromagnetic radiation are provided. Also provided are methods for using the devices to generate electromagnetic radiation. The radiation sources include an anisotropic electrically conducting thin film that is characterized by a periodically varying charge carrier mobility in the plane of the film. The periodic variation in carrier mobility gives rise to a spatially varying electric field, which produces electromagnetic radiation as charged particles pass through the film.
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
Electromagnetic wave scattering by Schwarzschild black holes.
Crispino, Luís C B; Dolan, Sam R; Oliveira, Ednilton S
2009-06-12
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. PMID:19658920
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.; Slepian, R. Michael; Nathenson, Richard D.; Williams, Robert S.
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 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.
Electromagnetic wave scattering by Schwarzschild black holes
Luís 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.
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.
611: Electromagnetic Theory Problem Sheet 4
Pope, Christopher
611: Electromagnetic Theory Problem Sheet 4 (1a) The angular momentum 3-vector L is defined by Li) Prove from the above that for the electromagnetic field, L = 1 4 r × (E × B) d3 x (b) Prove that dR dt = P E where R is the centre of mass of the electromagnetic field, defined by R Wd3x = rWd3x
Noncontacting ultrasonic and electromagnetic HTS tape NDE
Telschow, K.L.; Bruneel, F.W.; Walter, J.B.; Koo, L.S.
1996-10-01
Two noncontacting nondestructive evaluation techniques (electromagnetic and ultrasonic) for inspection of high temperature superconducting tapes are described. Results for Ag-clad BSCCO tapes are given.
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, ...
Detection of electromagnetic waves using MEMS antennas
Lavrik, Nickolay V; Tobin,; Bowland, Landon T
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 ...
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.
Calculation principles for a synchronous electromagnetic clutch
NASA Technical Reports Server (NTRS)
Panasenkov, M. A.
1978-01-01
A detailed explanation of the calculation principles, for a synchronous salient-pole electromagnetic clutch with lumped excitation windings is supplied by direct current. Practical recommendations are given.
Extremely low frequency electromagnetic fields
Wilson, B.W. . Chemical Sciences Dept.); Stevens, R.G. ); Anderson, L.E. . 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 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 weak turbulence theory revisited
Yoon, P. H.; Ziebell, L. F.; Gaelzer, R.; Pavan, J.
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.
Containerless processing using electromagnetic levitation
NASA Technical Reports Server (NTRS)
Gokhale, A. B.; Abbaschian, R.
1990-01-01
The theory and practice of containerless processing via electromagnetic (EM) levitation is reviewed briefly. The use of EM levitation for the processing of alloys is described with particular emphasis on the bulk melt supercooling phenomenon in a containerless environment. The various effects associated with rapid solidification via bulk melt supercooling are discussed with examples of Nb-Si alloys. It is suggested that a detailed analysis of such effects can be utilized to select the potentially most promising alloys for future space-based processing.
An electromagnetic world without polarization
NASA Astrophysics Data System (ADS)
Zeldovich, B. Ya; Tsai, C.-C.
2013-01-01
The majority of natural sources (black-bodies, fluorescent bulbs, etc) generate completely un-polarized light; the majority of detectors (eyes, photo-cameras, photomultipliers, etc) are polarization-insensitive. To reflect this, we attempt to describe approximately electromagnetic waves without polarization. Corresponding scalar equations are non-trivial modifications of standard d’Alembert and Helmholtz equations to the case of spatially inhomogeneous propagation speed v(\\mathbf{r})=1/\\sqrt{\\varepsilon (\\mathbf{r})\\mu (\\mathbf{r})}. A description of Fresnel reflection (FR) and Goos-Hänchen shift for total internal reflection phenomena is given on the basis of these modified equations.
Electromagnetic properties of massive neutrinos
Dobrynina, A. A. Mikheev, N. V.; Narynskaya, E. N.
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.
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
Toshihiro Nakanishi; Takehiro Otani; Yasuhiro Tamayama; Masao Kitano
2013-04-17
We propose a method for dynamically controlling the properties of a metamaterial that mimics electromagnetically induced transparency (EIT) by introducing varactor diodes to manipulate the structural symmetry of the metamaterial. Dynamic modulation of the EIT property enables the storage and retrieval of electromagnetic waves. We confirmed that the electromagnetic waves were stored and released, while maintaining the phase distribution in the propagating direction.
Melamed, Timor
Progress In Electromagnetics Research, Vol. 114, 317332, 2011 PULSED BEAM EXPANSION OF ELECTROMAGNETIC APERTURE FIELDS T. Melamed Department of Electrical and Computer Engineering Ben-Gurion University-based pulsed-beams expansion of planar aperture time- dependent electromagnetic fields. The propagating field
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.
Compton Sources of Electromagnetic Radiation
Geoffrey Krafft,Gerd Priebe
2011-01-01
When a relativistic electron beam interacts with a high-field laser beam, intense and highly collimated electromagnetic radiation will be generated through Compton scattering. Through relativistic upshifting and the relativistic Doppler effect, highly energetic polarized photons are radiated along the electron beam motion when the electrons interact with the laser light. For example, X-ray radiation can be obtained when optical lasers are scattered from electrons of tens-of-MeV beam energy. Because of the desirable properties of the radiation produced, many groups around the world have been designing, building, and utilizing Compton sources for a wide variety of purposes. In this review article, we discuss the generation and properties of the scattered radiation, the types of Compton source devices that have been constructed to date, and the prospects of radiation sources of this general type. Due to the possibilities of producing hard electromagnetic radiation in a device that is small compared to the alternative storage ring sources, it is foreseen that large numbers of such sources may be constructed in the future.
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.
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)
Long Pulse Fusion Physics Experiments Without Superconducting Electromagnets
Long Pulse Fusion Physics Experiments Without Superconducting Electromagnets Robert D. Woolley fusion physics experiments can be performed economically via resistive electromagnets designed for thermally steady-state operation. Possible fusion experiments using resistive electromagnets include long
Long Pulse Fusion Physics Experiments Without Superconducting Electromagnets
Long Pulse Fusion Physics Experiments Without Superconducting Electromagnets Robert D. Woolley fusion physics experiments can be performed economically via resistive electromagnets designed for thermally steadystate operation. Possible fusion experiments using resistive electromagnets include long
EE 818 -02 (3L) Electromagnetic Wave Propagation
Saskatchewan, University of
EE 818 - 02 (3L) Electromagnetic Wave Propagation Department of Electrical and Computer Engineering Winter 2014-15 Description: The fundamentals of electromagnetism and its applications. Includes Maxwell's equations, multi-pole fields, electromagnetic waves, reflection and refraction, retarded potentials
The Inverse Electromagnetic Scattering Problem for Anisotropic Media
Cakoni, Fioralba
The Inverse Electromagnetic Scattering Problem for Anisotropic Media Fioralba Cakoni1 , David. The inverse electromagnetic scattering problem for anisotropic media plays a special role in inverse. Introduction The inverse electromagnetic scattering problem for anisotropic media plays a special role
Electromagnetic Eavesdropping Risks of Flat-Panel Displays
Kuhn, Markus
Electromagnetic Eavesdropping Risks of Flat-Panel Displays Markus G. Kuhn University of Cambridge/ Abstract. Electromagnetic eavesdropping of computer displays first demonstrated to the general public shielded against such compromising electromagnetic emanations. The exact "TEMPEST" emis- sion limits
Electromagnetic gearing applications in hybrid-electric vehicles
Sodhi, Sameer
1994-01-01
of electromagnetic gears under various operating conditions. Electromagnetic gears can be used in hybrid electric propulsion systems as power sharing devices. This thesis explains the detailed operation of a new hybrid propulsion system utilizing electromagnetic...
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
Inferring internal structures of solar system bodies from electromagnetic induction
Strangeway, Robert J.
Inferring internal structures of solar system bodies from electromagnetic induction Krishan Hood et al. 1999 #12;The principle behind electromagnetic induction B (t) Eddy currents BInducedCalculated from 3 D MHD simulations · Electromagnetic induction from a subsurface conductorconductor. Obtained
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
Electromagnetically Induced Guiding of CounterPropagating Lasers in Plasmas
Electromagnetically Induced Guiding of CounterPropagating Lasers in Plasmas G. Shvets Princeton guiding length. This phenomenon of electromagneticallyinduced guiding can be utilized in laser interaction with another, counterpropagating pulse. Such electromagnetically induced guiding (EIG) occurs
Ultrashort electromagnetic pulses in graphene with disorder
NASA Astrophysics Data System (ADS)
Konobeeva, N. N.; Belonenko, M. B.
2015-08-01
Maxwell's equations describing an electromagnetic field propagating in graphene with disorder are analyzed. The spectrum of electrons for the graphene subsystem is chosen based on the renormalization group approach. An effective equation governing the vector potential of the electromagnetic field is derived and solved numerically. The dependence of the pulse shape on parameters of the problem is investigated.
NASA Applications for Computational Electromagnetic Analysis
NASA Technical Reports Server (NTRS)
Lewis, Catherine C.; Trout, Dawn H.; Krome, Mark E.; Perry, Thomas A.
2011-01-01
Computational Electromagnetic Software is used by NASA to analyze the compatibility of systems too large or too complex for testing. Recent advances in software packages and computer capabilities have made it possible to determine the effects of a transmitter inside a launch vehicle fairing, better analyze the environment threats, and perform on-orbit replacements with assured electromagnetic compatibility.
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.
Electromagnetic Scattering from Large Cavities: Iterative Methods
New York at Stoney Brook, State University of
Electromagnetic Scattering from Large Cavities: Iterative Methods J. S. Asvestas 27 Summit Street for the solution of electromagnetic scattering from a cavity, and show convergence using coarse grids which are two of monochromatic scattering by electrically large cavities in a perfectly conducting plane. Scattering by cavities
Can a wormhole generate electromagnetic field?
Mubasher Jamil
2010-05-09
We have considered the possibility of a slowly rotating wormhole surrounded by a cloud of charged particles. Due to slow rotation of the wormhole, the charged particles are dragged thereby producing an electromagnetic field. We have determined the strength of this electromagnetic field and the corresponding flux of radiation.
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.
Can a Wormhole Generate Electromagnetic Field?
NASA Astrophysics Data System (ADS)
Jamil, Mubasher
2010-07-01
We have considered the possibility of a rotating wormhole surrounded by a cloud of charged particles. Due to slow rotation of the wormhole, the charged particles are dragged, thereby producing an electromagnetic field. We have determined the strength of this electromagnetic field and the corresponding flux of radiation.
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,…
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)
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…
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 corrections to light hadron masses
A. Portelli; S. Dürr; Z. Fodor; J. Frison; C. Hoelbling; S. D. Katz; S. Krieg; T. Kurth; L. Lellouch; T. Lippert; K. K. Szabó; A. Ramos
2011-01-12
At the precision reached in current lattice QCD calculations, electromagnetic effects are becoming numerically relevant. We will present preliminary results for electromagnetic corrections to light hadron masses, based on simulations in which a $\\mathrm{U}(1)$ degree of freedom is superimposed on $N_f=2+1$ QCD configurations from the BMW collaboration.
Localization of fremions in rotating electromagnetic fields
B. V. Gisin
2015-06-15
Parameters of localization are defined in the lab and rotating frame for solutions of the Dirac equation in the field of a traveling circularly polarized electromagnetic wave and constant magnetic field. The radius of localization is of the order of the electromagnetic wavelength and lesser.
Noninvasive valve monitor using alternating electromagnetic field
Eissenberg, David M. (Oak Ridge, TN); Haynes, Howard D. (Knoxville, TN); Casada, Donald A. (Knoxville, TN)
1993-01-01
One or more electrical coils are carefully located on the outside of a valve body. An alternating current passing through the coil(s) results in an alternating electromagnetic field being transmitted into the valve body and valve internals. The electromagnetic field varies in intensity and polarity in the valve. As the position of a valve internal part is changed, the electromagnetic field throughout the valve body and its internals is altered. A passive receiver coil carefully located on the outside of the valve body detects the intensity of the electromagnetic field at that location as an induced electrical voltage in the coil. With the change in position of the valve internal part, there is a corresponding change in the induced voltage as a result of the alteration in the alternating electromagnetic field at that location. Changes in the voltage provide an indication of the position and motion of valve internals.
An experimentally validated electromagnetic energy harvester
NASA Astrophysics Data System (ADS)
Elvin, Niell G.; Elvin, Alex A.
2011-05-01
A relatively simple method for determining the electromechanical parameters of electromagnetic energy harvesters are presented in this paper. The optimal power generated through a load resistor at both off-resonance and resonance is derived analytically. The experimentally measured performance of a rudimentary electromechanical energy harvester using a rare-earth magnet shows good agreement with the results from the model. The parasitic generator coil resistance can have a profound effect on the overall performance of an electromagnetic generator by essentially acting to degrade the effective coupling coefficient. Data from the setup electromagnetic generator shows normalized power densities of 1.7 ?W/[(m/s 2) 2 cm 3] operating at a resonance frequency of 112.25 Hz. This power density is comparable with other electromagnetic devices of the same volume operating at these frequencies. The power output of the presented electromagnetic generator is comparable to equivalent piezoelectric generators.
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.
Hypercube-Computer Analysis Of Electromagnetic Scattering
NASA Technical Reports Server (NTRS)
Patterson, J. E.; Liewer, P. C.; Calalo, R. H.; Manshadi, F.
1990-01-01
Capabilities of hypercube and parallel processing demonstrated. Report describes use of Mark III Hypercube computer to analyze scattering of electromagnetic waves. Purpose of study to assess utility of parallel computing in such computation-intensive problems as large-scale electromagnetic scattering. Two electromagnetic codes based on different algorithms converted to run on Mark III Hypercube. First code implements finite-difference, time-domain solution of Maxwell's curl equations. Second code is Numerical Electromagnetics Code (NEC-2) which embodies frequency-domain method and developed to analyze electromagnetic responses of antennas and other metallic structures. On Mark III Hypercube with 32 active nodes, largest lattice contains about 2,048,000 unit cells.
Electromagnetic effects on quasilinear turbulent particle transport
Eriksson, Annika; Weiland, Jan
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.
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.
The electromagnetic momentum of static charge-current distributions
Jerrold Franklin
2013-05-06
The origin of electromagnetic momentum for general static charge-current distributions is examined. The electromagnetic momentum for static electromagnetic fields is derived by implementing conservation of momentum for the sum of mechanical momentum and electromagnetic momentum. The external force required to keep matter at rest during the production of the final static configuration produces the electromagnetic momentum. Examples of the electromagnetic momentum in static electric and magnetic fields are given. The `center of energy' theorem is shown to be violated by electromagnetic momentum. `Hidden momentum' is shown to be generally absent, and not to cancel electromagnetic momentum.
Electromagnetic structure of the deuteron
R. Gilman; Franz Gross
2001-11-06
Recent measurements of the deuteron electromagnetic structure functions A, B, and $T_{20}$ extracted from high energy elastic $ed$ scattering, and the cross sections and asymmetries extracted from high energy photodisintegration $\\gamma+d\\to n+p$, are reviewed and compared to theory. The theoretical calculations range from nonrelativistic and relativistic models using the traditional meson and baryon degrees of freedom, to effective field theories, to models based on the underlying quark and gluon degrees of freedom of QCD, including nonperturbative quark cluster models and perturbative QCD. We review what has been learned from these experiments, and discuss why elastic $ed$ scattering and photodisintegration seem to require very different theoretical approaches, even though they are closely related experimentally.
Ultrarelativistic electromagnetic pulses in plasmas
NASA Technical Reports Server (NTRS)
Ashour-Abdalla, M.; Leboeuf, J. N.; Tajima, T.; Dawson, J. M.; Kennel, C. F.
1981-01-01
The physical processes of a linearly polarized electromagnetic pulse of highly relativistic amplitude in an underdense plasma accelerating particles to very high energies are studied through computer simulation. An electron-positron plasma is considered first. The maximum momenta achieved scale as the square of the wave amplitude. This acceleration stops when the bulk of the wave energy is converted to particle energy. The pulse leaves behind as a wake a vacuum region whose length scales as the amplitude of the wave. The results can be explained in terms of a snow plow or piston-like action of the radiation on the plasma. When a mass ratio other than unity is chosen and electrostatic effects begin to play a role, first the ion energy increases faster than the electron energy and then the electron energy catches up later, eventually reaching the same value.
Electromagnetic braking for Mars spacecraft
NASA Technical Reports Server (NTRS)
Holt, A. C.
1986-01-01
Aerobraking concepts are being studied to improve performance and cost effectiveness of propulsion systems for Mars landers and Mars interplanetary spacecraft. Access to megawatt power levels (nuclear power coupled to high-storage inductive or capacitive devices) on a manned Mars interplanetary spacecraft may make feasible electromagnetic braking and lift modulation techniques which were previously impractical. Using pulsed microwave and magnetic field technology, potential plasmadynamic braking and hydromagnetic lift modulation techniques have been identified. Entry corridor modulation to reduce loads and heating, to reduce vertical descent rates, and to expand horizontal and lateral landing ranges are possible benefits. In-depth studies are needed to identify specific design concepts for feasibility assessments. Standing wave/plasma sheath interaction techniques appear to be promising. The techniques may require some tailoring of spacecraft external structures and materials. In addition, rapid response guidance and control systems may require the use of structurally embedded sensors coupled to expert systems or to artificial intelligence systems.
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.
Electromagnetically induced angular Talbot effect
NASA Astrophysics Data System (ADS)
Qiu, Tianhui; Yang, Guojian
2015-12-01
The discrete angular spectrum (angular Talbot effect) of a periodic grating illuminated by a suitable spherical wave front has been observed recently (Azaña and Chatellus 2104 Phys. Rev. Lett. 112 213902). In this paper we study the possibility of such a phenomenon being realized with a medium that has no macroperiodic structure itself. Tunable electromagnetically induced grating (EIG) could be such a kind of medium. We obtain an EIG based on the periodically modulated strong susceptibility due to the third-order nonlinear effect generated in a double ?-type four-level atomic system, and show the angular Talbot effect of an amplitude EIG, as well as a hybrid EIG, as the condition of the discrete phase-modulation shift of the illumination light front is satisfied. EIG parameters are tunable and the EIG-based angular Talbot effect may have the same potential applications as its periodic grating counterpart has.
Electromagnetic Induction with Neodymium Magnets
NASA Astrophysics Data System (ADS)
Wood, Deborah; Sebranek, John
2013-09-01
In April 1820, Hans Christian Ørsted 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 Ørsted'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.
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 Decays of Hyperons (II)
Y. Umino; F. Myhrer
1992-10-23
Excited negative parity hyperon masses are calculated in a chiral bag model in which the pion and the kaon fields are treated as perturbations. We also calculate the hadronic widths of $\\lama$ and $\\lamb$ as well as the coupling constants of the lightest $I=0$ excited hyperon to the meson-baryon channels, and discuss how the dispersive effects of the hadronic meson-baryon decay channels affect the excited hyperon masses. Meson cloud corrections to the electromagnetic decay widths of the two lightest excited hyperons into ground states $\\lamz$ and $\\sigz$ are calculated within the same model and are found to be small. Our results strengthen the argument that predictions of these hyperon radiative decay widths provide an excellent test for various quark models of hadrons.
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
Formal analysis of electromagnetic optics
NASA Astrophysics Data System (ADS)
Khan-Afshar, Sanaz; Hasan, Osman; Tahar, Sofiène
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.
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.
Electromagnetic Signatures of SMBH Coalescence
NASA Technical Reports Server (NTRS)
Schnittman, Jeremy
2012-01-01
When two supermassive black holes (SMBHs) approach within 1-10 mpc, gravitational wave (GW) losses begin to dominate the evolution of the binary, pushing the system to merge in a relatively small time. During this final inspiral regime, the system will emit copious energy in GWs, which should be directly detectable by pulsar timing arrays and space-based interferometers. At the same time, any gas or stars in the immediate vicinity of the merging 5MBHs can get heated and produce bright electromagnetic (EM) counterparts to the GW signals. We present here a number of possible mechanisms by which simultaneous EM and GW signals will yield valuable new information about galaxy evolution, accretion disk dynamics, and fundamental physics in the most extreme gravitational fields.
Broadband cavity electromagnetically induced transparency
Wei Xiaogang; Wang Yanhua; Zhang Jiepeng; Zhu Yifu
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.
Integrated Circuit Electromagnetic Immunity Handbook
NASA Astrophysics Data System (ADS)
Sketoe, J. G.
2000-08-01
This handbook presents the results of the Boeing Company effort for NASA under contract NAS8-98217. Immunity level data for certain integrated circuit parts are discussed herein, along with analytical techniques for applying the data to electronics systems. This handbook is built heavily on the one produced in the seventies by McDonnell Douglas Astronautics Company (MDAC, MDC Report E1929 of 1 August 1978, entitled Integrated Circuit Electromagnetic Susceptibility Handbook, known commonly as the ICES Handbook, which has served countless systems designers for over 20 years). Sections 2 and 3 supplement the device susceptibility data presented in section 4 by presenting information on related material required to use the IC susceptibility information. Section 2 concerns itself with electromagnetic susceptibility analysis and serves as a guide in using the information contained in the rest of the handbook. A suggested system hardening requirements is presented in this chapter. Section 3 briefly discusses coupling and shielding considerations. For conservatism and simplicity, a worst case approach is advocated to determine the maximum amount of RF power picked up from a given field. This handbook expands the scope of the immunity data in this Handbook is to of 10 MHz to 10 GHz. However, the analytical techniques provided are applicable to much higher frequencies as well. It is expected however, that the upper frequency limit of concern is near 10 GHz. This is due to two factors; the pickup of microwave energy on system cables and wiring falls off as the square of the wavelength, and component response falls off at a rapid rate due to the effects of parasitic shunt paths for the RF energy. It should be noted also that the pickup on wires and cables does not approach infinity as the frequency decreases (as would be expected by extrapolating the square law dependence of the high frequency roll-off to lower frequencies) but levels off due to mismatch effects.
Modeling Electromagnetic Scattering From Complex Inhomogeneous Objects
NASA Technical Reports Server (NTRS)
Deshpande, Manohar; Reddy, C. J.
2011-01-01
This software innovation is designed to develop a mathematical formulation to estimate the electromagnetic scattering characteristics of complex, inhomogeneous objects using the finite-element-method (FEM) and method-of-moments (MoM) concepts, as well as to develop a FORTRAN code called FEMOM3DS (Finite Element Method and Method of Moments for 3-Dimensional Scattering), which will implement the steps that are described in the mathematical formulation. Very complex objects can be easily modeled, and the operator of the code is not required to know the details of electromagnetic theory to study electromagnetic scattering.
Detection of electromagnetic waves using charged cantilevers
NASA Astrophysics Data System (ADS)
Datskos, P. G.; Lavrik, N. V.; Tobin, J. D.; Bowland, L. T.
2012-03-01
We describe micromechanical structures that are capable of sensing both electrostatic fields and electromagnetic fields over a wide frequency range. Typically, sensing of electromagnetic waves is achieved with electrically conducting antennas, which despite the many advantages do not exhibit high sensitivity over a broad frequency range. An important aspect of our present work is that, in contrast to traditional antennas, the dimensions of micromechanical oscillators sensitive to electromagnetic waves can be much smaller than the wavelength. We characterized the micromechanical oscillators and measured responses to electric fields and estimated the performance limits by evaluating the signal-to-noise ratio theoretically and experimentally.
Porous material for protection from electromagnetic radiation
Kazmina, Olga E-mail: bdushkina89@mail.ru; Dushkina, Maria E-mail: bdushkina89@mail.ru; Suslyaev, Valentin; Semukhin, Boris
2014-11-14
It is shown that the porous glass crystalline material obtained by a low temperature technology can be used not only for thermal insulation, but also for lining of rooms as protective screens decreasing harmful effect of electromagnetic radiation as well as to establish acoustic chambers and rooms with a low level of electromagnetic background. The material interacts with electromagnetic radiation by the most effective way in a high frequency field (above 100 GHz). At the frequency of 260 GHz the value of the transmission coefficient decreases approximately in a factor times in comparison with foam glass.
Interaction of electromagnetic fields and biological tissues
NASA Astrophysics Data System (ADS)
Darshan Shrivastava, Bhakt; Barde, Ravindra; Mishra, Ashutosh; Phadke, S.
2014-09-01
This paper deals with the electromagnetic field interact in biological tissues. It is actually one of the important challenges for the electromagnetic field for the recent years. The experimental techniques are use in Broad-band Dielectric Measurement (BDM) with LCR meters. The authors used Bones and scales of Fish taken from Narmada River (Rajghat Dist. Barwani) as biological tissues. Experimental work carried out done in inter-university consortium (IUC) Indore. The major difficulties that appear are related to the material properties, to the effect of the electromagnetic problem and to the thermal model of the biological tissues.
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.
Expanding use of pulsed electromagnetic field therapies.
Markov, Marko S
2007-01-01
Various types of magnetic and electromagnetic fields are now in successful use in modern medicine. Electromagnetic therapy carries the promise to heal numerous health problems, even where conventional medicine has failed. Today, magnetotherapy provides a non invasive, safe, and easy method to directly treat the site of injury, the source of pain and inflammation, and a variety of diseases and pathologies. Millions of people worldwide have received help in treatment of the musculoskeletal system, as well as for pain relief. Pulsed electromagnetic fields are one important modality in magnetotherapy. Recent technological innovations, implementing advancements in computer technologies, offer excellent state-of-the-art therapy. PMID:17886012
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.
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.
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.
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.
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.
Cédric Lorcé
2009-01-27
In a set of two papers, we propose to study an old-standing problem, namely the electromagnetic interaction for particles of arbitrary spin. Based on the assumption that light-cone helicity at tree level and $Q^2=0$ should be conserved non-trivially by the electromagnetic interaction, we are able to derive \\emph{all} the natural electromagnetic moments for a pointlike particle of \\emph{any} spin. In this first paper, we propose a transparent decomposition of the electromagnetic current in terms of covariant vertex functions. We also define in a general way the electromagnetic multipole form factors, and show their relation with the electromagnetic moments. Finally, by considering the Breit frame, we relate the covariant vertex functions to multipole form factors.
Dr. S. Cruz-Pol, INEL 4152-Electromagnetics
Cruz-Pol, Sandra L.
JdlH Cruz-Pol, Electromagnetics UPRM Would magnetism would produce electricity? Ø Eleven years later Electromagnetics was born! Ø This is the principle of motors, hydro-electric generators and transformers operationDr. S. Cruz-Pol, INEL 4152- Electromagnetics Electrical Engineering, UPRM 1 Electromagnetic
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
Electromagnetic Side Channels of an FPGA Implementation of AES
International Association for Cryptologic Research (IACR)
Electromagnetic Side Channels of an FPGA Implementation of AES Vincent Carlier, HervÂ´e Chabanne processed. Another side channel is the one that exploits the Electromagnetic (EM) emanations. Indeed references. In [QS01, GMO01], Simple Electromagnetic Analysis (SEMA) and Differential Electromagnetic
Electromagnetic Side Channels of an FPGA Implementation of AES
International Association for Cryptologic Research (IACR)
Electromagnetic Side Channels of an FPGA Implementation of AES Vincent Carlier, Hervâ??e Chabanne processed. Another side channel is the one that exploits the Electromagnetic (EM) emanations. Indeed references. In [QS01, GMO01], Simple Electromagnetic Analysis (SEMA) and Di#erential Electromagnetic Analysis
Least-squares methods for computational electromagnetics
Kolev, Tzanio Valentinov
2004-11-15
The modeling of electromagnetic phenomena described by the Maxwell's equations is of critical importance in many practical applications. The numerical simulation of these equations is challenging and much more involved ...
Galium Electromagnetic (GEM) Thruster Concept and Design
NASA Technical Reports Server (NTRS)
Polzin, Kurt A.; Markusic, Thomas E.
2005-01-01
We describe the design of a new type of two-stage pulsed electromagnetic accelerator, the gallium electromagnetic (GEM) thruster. A schematic illustration of the GEM thruster concept is given. In this concept, liquid gallium propellant is pumped into the first stage through a porous metal electrode using an electromagnetic pump. At a designated time, a pulsed discharge (approx. 10-50 J) is initiated in the first stage, ablating the liquid gallium from the porous electrode surface and ejecting a dense thermal gallium plasma into the second state. The presence of the gallium plasma in the second stage serves to trigger the high-energy (approx. 500 J), second-stage pulse which provides the primary electromagnetic (j x B) acceleration.
A pulsed electromagnet controller for prepolarized MRI
Nam, Hyokwon
2001-01-01
fundamental measure of scanner performance. To enable PMRI experiments, a pulsed electromagnet controller has been designed and built. In this thesis, the theory of the controller is presented and results are discussed....
Electromagnetic Detection of a Perfect Invisibility Cloak
Zhang, Baile
A perfect invisibility cloak is commonly believed to be undetectable from electromagnetic (EM) detection because it is equivalent to a curved but empty EM space created from coordinate transformation. Based on the intrinsic ...
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.
Avionics electromagnetic interference immunity and environment
NASA Technical Reports Server (NTRS)
Clarke, C. A.
1986-01-01
Aircraft electromagnetic spectrum and radio frequency (RF) field strengths are charted, profiling the higher levels of electromagnetic voltages encountered by the commercial aircraft wiring. Selected military, urban, and rural electromagnetic field levels are plotted and provide a comparison of radiation amplitudes. Low frequency magnetic fields and electric fields from 400 H(Z) power systems are charted versus frequency and wire separation to indicate induced voltages on adjacent or neighboring circuits. Induced EMI levels and attenuation characteristics of electric, magnetic, RF fields, and transients are plotted and graphed for common types of wire circuits. The significance of wire circuit returns and shielding is emphasized to highlight the techniques that help block the paths of electromagnetic interference and maintain avionic interface signal quality.
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)
Cartan's Supersymmetry and Weak and Electromagnetic Interactions
Sadataka Furui
2015-07-06
We apply the Cartan's supersymmetric model to the weak interaction of hadrons. The electromagnetic currents are transformed by $G_{12},G_{123},G_{13},G_{132}$ and the factor$(1-\\gamma_5)$ is inserted between $l \\bar\
Computes Generalized Electromagnetic Interactions Between Structures
Energy Science and Technology Software Center (ESTSC)
1999-02-20
Object oriented software for computing generalized electromagnetic interactions between structures in the frequency domains. The software is based on integral equations. There is also a static integral equation capability.
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.
Nanomechanical electric and electromagnetic field sensor
Datskos, Panagiotis George; Lavrik, Nickolay
2015-03-24
The present invention provides a system for detecting and analyzing at least one of an electric field and an electromagnetic field. The system includes a micro/nanomechanical oscillator which oscillates in the presence of at least one of the electric field and the electromagnetic field. The micro/nanomechanical oscillator includes a dense array of cantilevers mounted to a substrate. A charge localized on a tip of each cantilever interacts with and oscillates in the presence of the electric and/or electromagnetic field. The system further includes a subsystem for recording the movement of the cantilever to extract information from the electric and/or electromagnetic field. The system further includes a means of adjusting a stiffness of the cantilever to heterodyne tune an operating frequency of the system over a frequency range.
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.
Electromagnetic ion/ion cyclotron instability
Winske, D.; McKean, M.E. ); Omidi, N.; Chou, V. )
1991-01-01
Linear analysis and hybrid simulations are used to investigate the properties of a new electromagnetic ion beam instability. Some applications of the instability in space are also discussed. 7 refs., 1 fig.
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, ...
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.
Composite Vector Particles in External Electromagnetic Fields
Davoudi, Zohreh
2015-01-01
Lattice quantum chromodynamics (QCD) studies of electromagnetic properties of hadrons and light nuclei, such as magnetic moments and polarizabilities, have proven successful with the use of background field methods. With an implementation of nonuniform background electromagnetic fields, properties such as charge radii and higher electromagnetic multipole moments (for states of higher spin) can be additionally obtained. This can be achieved by matching lattice QCD calculations to a corresponding low-energy effective theory that describes the static and quasi-static response of hadrons and nuclei to weak external fields. With particular interest in the case of vector mesons and spin-1 nuclei such as the deuteron, we present an effective field theory of spin-1 particles coupled to external electromagnetic fields. To constrain the charge radius and the electric quadrupole moment of the composite spin-1 field, the single-particle Green's functions in a linearly varying electric field in space are obtained within t...
Analytic properties of the electromagnetic Green's function
Gralak, Boris; Soriano, Gabriel
2015-01-01
A general expression of the electromagnetic Green's function is derived from the inverse Helmholtz operator, where a second frequency has been introduced as a new degree of freedom. The first frequency results from the frequency decomposition of the electromagnetic field while the second frequency is associated with the dispersion of the dielectric permittivity. Then, it is shown that the electromagnetic Green's function is analytic with respect to these two complex frequencies as soon as they have positive imaginary part. Such analytic properties are also extended to complex wavevectors. Next, Kramers-Kronig expressions for the inverse Helmholtz operator and the electromagnetic Green's function are derived. In addition, these Kramers-Kronig expressions are shown to correspond to the well-known eigengenmodes expansion of the Green's function established in simple situations. Finally, the second frequency introduced as a new degree of freedom is exploited to characterize non-dispersive systems.
Analytic properties of the electromagnetic Green's function
Boris Gralak; Anne-Laure Fehrembach; Gabriel Soriano
2015-12-15
A general expression of the electromagnetic Green's function is derived from the inverse Helmholtz operator, where a second frequency has been introduced as a new degree of freedom. The first frequency results from the frequency decomposition of the electromagnetic field while the second frequency is associated with the dispersion of the dielectric permittivity. Then, it is shown that the electromagnetic Green's function is analytic with respect to these two complex frequencies as soon as they have positive imaginary part. Such analytic properties are also extended to complex wavevectors. Next, Kramers-Kronig expressions for the inverse Helmholtz operator and the electromagnetic Green's function are derived. In addition, these Kramers-Kronig expressions are shown to correspond to the well-known eigengenmodes expansion of the Green's function established in simple situations. Finally, the second frequency introduced as a new degree of freedom is exploited to characterize non-dispersive systems.
The classical geometrization of the electromagnetism
NASA Astrophysics Data System (ADS)
de Araujo Duarte, Celso
2015-08-01
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 at first-order of approximation the electromagnetism constitutes a geometric structure aside other phenomena as gravitation, and that magnetic monopoles do not exist at least up to this order of approximation. Even though being limited, the model is consistent and offers the possibility of an experimental test of validity.
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.
The classical geometrization of the electromagnetism
Celso de Araujo Duarte
2015-08-13
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 at first order of approximation the electromagnetism constitutes a geometric structure aside other phenomena as gravitation, and that magnetic monopoles do not exist at least up to this order of approximation. Even though being limited, the model is consistent and offers the possibility of an experimental test of validity.
Working principle of an electromagnetic wiping system
NASA Astrophysics Data System (ADS)
Ernst, R.; Fautrelle, Y.; Bianchi, A.-M.; Iliescu, M.
2009-03-01
In galvanizing lines, the gas knife wiping device works well for controlling the zinc coating thickness up to 2 to 3 m/s strip velocities. But for higher velocities, a strong liquid zinc splash risk forbids the gas pressure increase, which would be necessary to keep the same thickness control efficiency of the knives. That is why a complementary electromagnetic wiping system, whose purpose is to pre-wipe the liquid zinc before the gas knives take over, is presented here. After mentioning different kinds of AC and DC possible electromagnetic solutions, a DC field electromagnetic brake (EMB) system based on the use of permanent magnets is selected for a future experimental implementation. In order to better understand the electromagnetic and fluid mechanics phenomena, an analytical model and then different numerical models are presented here. These models show an interesting wiping effect on the liquid zinc, which seems promising for a future experimental pilot design. Figs 8, Refs 9.
Sati, Priti; Tripathi, V. K.
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.
Calculation of electromagnetic force in electromagnetic forming process of metal sheet
Xu Da; Liu Xuesong; Fang Kun; Fang Hongyuan
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.
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.
Electromagnetic momentum conservation in media
Brevik, Iver; Ellingsen, Simen A.
2011-03-15
That static electric and magnetic fields can store momentum may be perplexing, but is necessary to ensure total conservation of momentum. Simple situations in which such field momentum is transferred to nearby bodies and point charges have often been considered for pedagogical purposes, normally assuming vacuum surroundings. If dielectric media are involved, however, the analysis becomes more delicate, not least since one encounters the electromagnetic energy-momentum problem in matter, the 'Abraham-Minkowski enigma', of what the momentum is of a photon in matter. We analyze the momentum balance in three nontrivial examples obeying azimuthal symmetry, showing how the momentum conservation is satisfied as the magnetic field decays and momentum is transferred to bodies present. In the last of the examples, that of point charge outside a dielectric sphere in an infinite magnetic field, we find that not all of the field momentum is transferred to the nearby bodies; a part of the momentum appears to vanish as momentum flux towards infinity. We discuss this and other surprising observations which can be attributed to the assumption of magnetic fields of infinite extent. We emphasize how formal arguments of conserved quantities cannot determine which energy-momentum tensor is more 'correct', and each of our conservation checks may be performed equally well in the Minkowski or Abraham framework.
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 8×8 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 8×8 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 antenna modeling (EAM) system
NASA Astrophysics Data System (ADS)
Packer, Malcolm; Powers, Robert; Tsitsopoulos, Paul
1994-12-01
The determination of foreign communications capabilities and intent is an important assessment function performed by the USAF National Air Intelligence Center (NAIC). In this context, Rome Laboratory became the NAIC engineering agent for the development of an NAIC requirement for the rapid analysis and evaluation of antenna structures based on often vague to sometimes detailed dimensional information. To this end, the Rome Laboratory sponsored development of the Electromagnetic Antenna Modeling (EAM) System, a state-of-the-art Pascal program with an MS Windows graphical user interface (GUI) pre- and post-processor. Users of NAIC capabilities initiate antenna analysis efforts that range from simple parametric studies to more complex, detailed antenna design and communication-system evaluations. Accordingly, EAM provides a modeling capability 'matched' to the sophistication of the individual analyst, with features appropriate for users ranging from nontechnical analysts to experienced antenna engineers. This capability is particularly valuable in the military-intelligence environment, in which high-speed assessments are required. In particular, EAM meets the specific antenna-analysis requirements of NAIC with a versatile graphical user interface.
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.
Electromagnetic Properties of Detonating Explosives
NASA Astrophysics Data System (ADS)
Chambers, Paul G.; Lee, Richard J.; Oxby, Troy; Perger, Warren; Kunz, Barry
2001-06-01
Current theories of reaction processes suggest that changes in electronic band structure and radiation producing dipole oscillations occur during shock loading of an energetic crystal prior to detonation. To test these theories, a broadband antenna, capable of measuring polarization, was employed to observe shock-induced electromagnetic radiation from a crystalline explosive, RDX. The frequency spectra from these experiments were analyzed using time/frequency Fourier methods. Changes in conductivity resulting from this shock loading were also measured at the opposite end of the crystal from the shock source. A four-point-probe arrangement was used to eliminate errors involving lead resistance. This arrangement uses two leads and a fast discharge circuit to pass current through the crystal interface at the time conductivity begins to change in conjunction with the arrival of the shock wave. Two separate leads are used to simultaneously measure the voltage. Voltage and current data are used to construct conductance versus time profiles preceding and during the detonation process. Also reported are corresponding light (observed with a high-speed electronic camera) and microwave emission observed during the passing of the shock wave in the RDX crystal prior to detonation.
Apparatus and Methods for Mitigating Electromagnetic Emissions
NASA Technical Reports Server (NTRS)
Geng, Steven M. (Inventor); Niedra, Janis M. (Inventor)
2013-01-01
Apparatus, methods, and other embodiments associated with mitigation of magnetic fields are described herein. In an embodiment, a method for mitigating an electromagnetic field includes positioning a mitigating coil around a linear alternator of linear motor so that the mitigating coil is coaxially located with an alternator coil; arranging the mitigating coil to generate a field to mitigate an electromagnetic field generated by the alternator coil; and passing an induced current from the alternator coil through the mitigating coil.
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, 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.
Electromagnetic Transport from Microtearing Mode Turbulence
Guttenfelder, W.; Kaye, S. M.; Bell, R. E.; Hammett, G. W.; LeBlanc, B. P.; Mikkelsen, D. R.; Candy, J.; Nevins, W. M.; Wang, E.; Yuh, H.
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.
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.
Differential Cross Sections for Electromagnetic Dissociation
John W. Norbury; Anne Adamczyk
2006-12-19
Differential cross sections for electromagnetic dissociation in nucleus-nucleus collisions are calculated. The kinetic energy distribution is parameterized with a Boltzmann distribution and the angular distribution is assumed isotropic in the projectile frame. In order to be useful for three-dimensional transport codes, these cross sections are available in both the projectile and lab frames. Comparison between theory and experiment is good. The formalism applies to single and multiple nucleon removal, alpha particle removal, and fission in electromagnetic reactions of nuclei.
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.
Chiral electromagnetic waves in Weyl semimetals
NASA Astrophysics Data System (ADS)
Zyuzin, Alexander A.; Zyuzin, Vladimir A.
2015-09-01
We show that Weyl semimetals with broken time-reversal symmetry can host chiral electromagnetic waves. The magnetization that results in a momentum-space separation of a pair of opposite chirality Weyl nodes is also responsible for the nonzero gyrotropy parameter in the system. It is then shown that a chiral electromagnetic wave can propagate in a region of space where the gyrotropy parameter changes sign. Such waves are analogs of quantum Hall edge states for photons.
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.
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.
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, 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.
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.
Singular Modes of the Electromagnetic Field
Neil V. Budko; Alexander B. Samokhin
2006-06-15
We show that the mode corresponding to the point of essential spectrum of the electromagnetic scattering operator is a vector-valued distribution representing the square root of the three-dimensional Dirac's delta function. An explicit expression for this singular mode in terms of the Weyl sequence is provided and analyzed. An essential resonance thus leads to a perfect localization (confinement) of the electromagnetic field, which in practice, however, may result in complete absorption.
Electromagnetic fields and cancer risks.
Thériault, G
1992-01-01
Cancer was first associated with exposure to electromagnetic fields (EMF) in 1979 when Wertheimer and Leeper reported that children dying from cancer resided more often in homes believed to be exposed to higher EMF than did healthy control children. The risks were as high as 2.23 (1.56-3.18) 3.09 (1.68-5.71) for all cancers, 2.98 (1.72-5.15) for leukemia and 2.40 (1.08-5.36) for brain cancers. Wire configuration around houses was used as a surrogate for direct EMF exposure measurements. Wertheimer's finding of an association between cancer and wire configuration around houses has been replicated in two recent studies. However, direct measurement of EMF fields in houses of cancer children have not yielded the same results as the wire configuration around houses, thereby jeopardizing the hypothesis of an association between EMF and cancer. To comprehend the putative association between residential exposure to EMF and childhood cancer, one would have to understand what is hidden behind the notion of 'wire configuration' around the house. In parallel with residential studies, scores of studies were conducted among workers occupationally exposed to EMF. What have we learned from these occupational studies? Hypotheses generating and case control studies have revealed the existence of an excess risk of leukemia among electrical workers. Pooled results have estimated the risk for all leukemia to be 1.18 (1.09-1.29) and for acute myeloid leukemia 1.46 (1.27-1.64). An increased risk of leukemia among electrical workers does not necessarily mean that EMF is a causal agent, other chemicals such as benzene, creosote, solvent, could possibly account for it but this has yet to be confirmed.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1626106
Is Electromagnetic Gravity Control Possible?
Vargas, Jose G.; Torr, Douglas G.
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.
Electromagnetic energy and food processing.
Mudgett, R
1988-01-01
The use of electromagnetic energy in food processing is reviewed with respect to food safety, nutritional quality, and organoleptic quality. The effects of nonionizing radiation sources such as microwave and radio-frequency energy and ionizing radiation sources, e.g. radioactive cobalt-60 and caesium-137, on the inactivation of microbes and nutrients are compared with those of conventional heating processes both in terms of their kinetic behavior and their mechanisms of interaction with foods. The kinetics of microwave and conventional thermal inactivation are considered for a generalized nth-order model based on time and temperature conditions. However, thermal inactivation effects are often modeled by 1st-order kinetics. Microbial and nutrient inactivation by ionizing sources are considered for a 1st-order model based on radiation dose. Both thermal and radiation resistance concepts are reviewed and some typical values of radiation resistance are given for sensitive vegetative bacterial cells, yeasts, and molds and for resistant bacterial spores and viruses. Nonionizing microwave energy sources are increasingly used in home and industrial food processing and are well-accepted by the American public. But, despite recent Food and Drug Administration approval of low and intermediate ionizing radiation dose levels for grains and other plants products and the fact that irradiated foods are sold in more than 20 countries of the world, public fears in the U.S. about nuclear energy may limit the role of ionizing radiation in food processing and preservation and may also limit the use of nuclear fuels as an alternate source of electrical energy. PMID:3072397
Nonholonomic catheter path reconstruction using electromagnetic tracking
NASA Astrophysics Data System (ADS)
Lugez, Elodie; Sadjadi, Hossein; Akl, Selim G.; Fichtinger, Gabor
2015-03-01
Catheter path reconstruction is a necessary step in many clinical procedures, such as cardiovascular interventions and high-dose-rate brachytherapy. To overcome limitations of standard imaging modalities, electromagnetic tracking has been employed to reconstruct catheter paths. However, tracking errors pose a challenge in accurate path reconstructions. We address this challenge by means of a filtering technique incorporating the electromagnetic measurements with the nonholonomic motion constraints of the sensor inside a catheter. The nonholonomic motion model of the sensor within the catheter and the electromagnetic measurement data were integrated using an extended Kalman filter. The performance of our proposed approach was experimentally evaluated using the Ascension's 3D Guidance trakStar electromagnetic tracker. Sensor measurements were recorded during insertions of an electromagnetic sensor (model 55) along ten predefined ground truth paths. Our method was implemented in MATLAB and applied to the measurement data. Our reconstruction results were compared to raw measurements as well as filtered measurements provided by the manufacturer. The mean of the root-mean-square (RMS) errors along the ten paths was 3.7 mm for the raw measurements, and 3.3 mm with manufacturer's filters. Our approach effectively reduced the mean RMS error to 2.7 mm. Compared to other filtering methods, our approach successfully improved the path reconstruction accuracy by exploiting the sensor's nonholonomic motion constraints in its formulation. Our approach seems promising for a variety of clinical procedures involving reconstruction of a catheter path.
Building health: The need for electromagnetic hygiene?
NASA Astrophysics Data System (ADS)
Jamieson, Isaac A.; Holdstock, Paul; ApSimon, Helen M.; Bell, J. Nigel B.
2010-04-01
Whilst the electromagnetic nature of the built environment has changed considerably over the past century, little thought is at present given to the possible advantages of creating electromagnetic microenvironments that more closely resemble those found in nature and/or developing biologically-friendly technology aligned more closely to its operating principles. This review paper examines how more natural exposures to a variety of electromagnetic phenomena could be re-introduced into the built environment, possible benefits that might arise, and discusses the extent to which there may be tangible benefits obtainable from introducing more rigorous properly considered electromagnetic hygiene measures. Amongst the matters discussed are: the effects of different materials, finishes and electrical items on charge generation (and the effects of excess charge on contaminant deposition); the possible benefits of suitably grounding conductive objects (including humans) in order to reduce excess charge and contaminant deposition; how the presence of vertical electric field regimes, similar to those found in nature, may enhance biological performance; and possible pitfalls to avoid when seeking to introduce appropriate electromagnetic hygiene regimes.
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.
Power law inflation with electromagnetism
Luo, Xianghui; Isenberg, James
2013-07-15
We generalize Ringström’s global future causal stability results (Ringström 2009) [11] for certain expanding cosmological solutions of the Einstein-scalar field equations to solutions of the Einstein–Maxwell-scalar field system. In particular, after noting that the power law inflationary spacetimes (M{sup n+1},g{sup -hat}, ?{sup -hat}) considered by Ringström (2009) in [11] are solutions of the Einstein–Maxwell-scalar field system (with exponential potential) as well as of the Einstein-scalar field system (with the same exponential potential), we consider (nonlinear) perturbations of initial data sets of these spacetimes which include electromagnetic perturbations as well as gravitational and scalar perturbations. We show that if (as in Ringström (2009) [11]) we focus on pairs of relatively scaled open sets U{sub R{sub 0}}?U{sub 4R{sub 0}} on an initial slice of (M{sup n+1},g{sup -hat}), and if we choose a set of perturbed data which on U{sub 4R{sub 0}} is sufficiently close to that of (M{sup n+1},g{sup -hat},?{sup -hat}, A{sup -hat} = 0), then in the maximal globally hyperbolic spacetime development (M{sup n+1},g,?,A) of this data via the Einstein–Maxwell-scalar field equations, all causal geodesics emanating from U{sub R{sub 0}} are future complete (just as in (M{sup n+1},g{sup -hat})). We also verify that, in a certain sense, the future asymptotic behavior of the fields in the spacetime developments of the perturbed data sets does not differ significantly from the future asymptotic behavior of (M{sup n+1},g{sup -hat}, ?{sup -hat}, A{sup -hat} = 0). -- Highlights: •We prove stability of expanding solutions of the Einstein–Maxwell-scalar field equations. •All nearby solutions are geodesically complete. •The topology of the initial slice is irrelevant to our stability results.
Planar electromagnetic band-gap structure based on graphene
NASA Astrophysics Data System (ADS)
Dong, Yanfei; Liu, Peiguo; Yin, Wen-Yan; Li, Gaosheng; Yi, Bo
2015-06-01
Electromagnetic band-gap structure with slow-wave effect is instrumental in effectively controlling electromagnetic wave propagation. In this paper, we theoretically analyze equivalent circuit model of electromagnetic band-gap structure based on graphene and evaluate its potential applications. Graphene electromagnetic band-gap based on parallel planar waveguide is investigated, which display good characteristics in dynamically adjusting the electromagnetic wave propagation in terahertz range. The same characteristics are retrieved in a spiral shape electromagnetic band-gap based on coplanar waveguide due to tunable conductivity of graphene. Various potential terahertz planar devices are expected to derive from the prototype structures.
Electromagnetic processes in the atmosphere of pulsars
NASA Technical Reports Server (NTRS)
Yukhimuk, A. K.
1974-01-01
The work consists of two parts. The first deals with the fine structure of radio pulses. Based on kinetic theory, processes occurring in the plasma shell of a pulsar when external electromagnetic radiation is present are investigated. It is shown that electromagnetic waves cause electrons to drift relative to ions, and initiate longitudinal oscillations. A dispersion equation describing the longitudinal oscillations in magnetized plasma is derived. Conditions for excitation of oscillations are found. Correlation functions of electron density are calculated, along with the coefficients of electromagnetic wave scattering. It is shown that variations in the amplitude of pulsar pulses are associated with scintillations caused by fluctuations in the plasma electron density. The second part of the study presents a mechanism for the radio emission of pulsars. The model of a rotating and a pulsating star, a neutron star with dipolar or more complex magnetic field, is examined.
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.
Interactions between electromagnetic fields and cells
Chiabrera, A.; Nicolini, C.; Schwan, H.P.
1985-01-01
This book reviews the biological targets of electromagnetic exposure at the membrane and nuclear level. Electrical and electrochemical modelling of electromagnetically exposed cells are presented. Field effects on the interaction between ligands and their binding sites are studied and the polyelectrolyte theory and related experiments are presented. Field Force effects, and the biological effectiveness of pulsed or sinusoidal low-amplitude electromagnitic fields are demonstrated. Finally, attention is paid to field effects at the subcellular and cellular levels. EM-field induced force effects, frequency-dependent bilogical effects of low intensity microwaves and AC field effects of and by living cells are topics of discussion. Interaction forces between microscopic particles in an external electromagnetic field and cyclotron resonance in membrane transport are also examined.
Electromagnetically driven dwarf tornados in turbulent convection
NASA Astrophysics Data System (ADS)
Kenjereš, Saša
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<=5×109). 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.
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.
Near-field thermal electromagnetic transport
Edalatpour, Sheila
2015-01-01
A general near-field thermal electromagnetic transport formalism that is independent of the size, shape and number of heat sources is derived. The formalism is based on fluctuational electrodynamics, where fluctuating currents due to thermal agitation are added into Maxwell's curl equations, and is thus valid for heat sources in local thermodynamic equilibrium. Using a volume integral formulation, it is shown that the proposed formalism is a generalization of the classical electromagnetic scattering framework in which thermal emission is implicitly assumed to be negligible. The near-field thermal electromagnetic transport formalism is afterwards applied to a problem involving three spheres exchanging thermal radiation, where all multipolar interactions are taken into account. Using the thermal discrete dipole approximation, it is shown that depending on the dielectric function, the presence of a third sphere slightly affects the spatial distribution of power absorbed compared to the two-sphere case. The forma...
Cartan's Supersymmetry and Weak and Electromagnetic Interactions
NASA Astrophysics Data System (ADS)
Furui, Sadataka
2015-10-01
We apply the Cartan's supersymmetric model to the weak interaction of hadrons. The electromagnetic currents are transformed by G 12, G 123, G 13, G 132 and the factor is inserted between or when the photon is replaced by , and between or when the photon is replaced by Z. Electromagnetic currents in the Higgs boson H 0 decay into 2 and decay into and in which leptons are replaced by quarks are also studied. A possibility that the boson near the theshold GeV) is the Higgs boson partner h 0 is discussed. We adopt Dirac lepton neutrinos and Majorana quark neutrinos, and construct a model that satisfy the Z 3 symmetry of the lepton sector and the quark sector, by adding two right-handed neutrinos whose left-handed partner cannot be detected by our electro-magnetic detectors.
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 and Gravitational Waves: the Third Dimension
Gerald E. Marsh
2011-11-23
Plane electromagnetic and gravitational waves interact with particles in such a way as to cause them to oscillate not only in the transverse direction but also along the direction of propagation. The electromagnetic case is usually shown by use of the Hamilton-Jacobi equation and the gravitational by a transformation to a local inertial frame. Here, the covariant Lorentz force equation and the second order equation of geodesic deviation followed by the introduction of a local inertial frame are respectively used. It is often said that there is an analogy between the motion of charged particles in the field of an electromagnetic wave and the motion of test particles in the field of a gravitational wave. This analogy is examined and found to be rather limited. It is also shown that a simple special relativistic relation leads to an integral of the motion, characteristic of plane waves, that is satisfied in both cases.
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).
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 currents induced by color fields
Naoto Tanji
2015-11-19
The quark production in classical color fields is investigated with a focus on the induction of an electromagnetic current by produced quarks. We show that the color SU(2) and the SU(3) theories lead significantly different results for the electromagnetic current. In uniform SU(2) color fields, the net electromagnetic current is not generated, while in SU(3) color fields the net current is induced depending on the color direction of background fields. Also the numerical study of the quark production in inhomogeneous color fields is done. Motivated by gauge field configurations provided by the color glass condensate framework, we introduce an ensemble of randomly distributed color electric fluxtubes. The spectrum of photons emitted from the quarks by a classical process is shown.
Drift effects on electromagnetic geodesic acoustic modes
Sgalla, R. J. F.
2015-02-15
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 ?{sub r}???25?cm, i.e., an order of magnitude higher than the usual value for zonal flows (ZFs)
Electromagnetic energy momentum in dispersive media
Philbin, T. G.
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.
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 induced absorption via incoherent collisions
Yang Xihua; Sheng Jiteng; Xiao Min
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.
Electromagnetic currents induced by color fields
Tanji, Naoto
2015-01-01
The quark production in classical color fields is investigated with a focus on the induction of an electromagnetic current by produced quarks. We show that the SU(2) and the SU(3) theories lead significantly different results for the electromagnetic current. In uniform SU(2) color fields, the net electromagnetic current is not generated, while for SU(3) the net current is induced depending on the color direction of background fields. Also the numerical study of the quark production in inhomogeneous color fields is done. Motivated by gauge field configurations provided by the color glass condensate framework, we introduce an ensemble of randomly distributed color electric fluxtubes. The spectrum of photons emitted from the quarks by a classical process is shown.
Electromagnetic effects on toroidal momentum transport
Mahmood, M. Ansar; Eriksson, A.; Weiland, J.
2010-12-15
A parametric study of electromagnetic effects on toroidal momentum transport has been performed. The work is based on a new version of the Weiland model where symmetry breaking toroidicity effects derived from the stress tensor have been taken into account. The model includes a self-consistent calculation of the toroidal momentum diffusivity, which contains both diagonal and off-diagonal contributions to the momentum flux. It is found that electromagnetic effects considerably increase the toroidal momentum pinch. They are sometimes strong enough to make the total toroidal momentum flux inward.
Device and method for redirecting electromagnetic signals
Garcia, Ernest J. (823 Piedra Larga, NE., Albuquerque, NM 87123)
1999-01-01
A device fabricated to redirect electromagnetic signals, the device including a primary driver adapted to provide a predetermined force, a linkage system coupled to the primary driver, a pusher rod rotationally coupled to the linkage system, a flexible rod element attached to the pusher rod and adapted to buckle upon the application of the predetermined force, and a mirror structure attached to the flexible rod element at one end and to the substrate at another end. When the predetermined force buckles the flexible rod element, the mirror structure and the flexible rod element both move to thereby allow a remotely-located electromagnetic signal directed towards the device to be redirected.
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.
Electromagnetic mass model admitting conformal motion
Ray, Saibal; Rahaman, F; Kalam, M; Chakraborty, K
2008-01-01
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 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 fields in Khan-Penrose spacetime
Helliwell, T.M. ); Konkowski, D.A. )
1990-04-15
The behavior of test electromagnetic waves on the Khan-Penrose colliding gravitational-wave spacetime is used to probe the nature of the quasiregular singularities present. It is argued that the divergence of stress-energy scalars for most wave modes makes these singularities unstable, converting them into scalar curvature singularities. However, a special subset of modes does not lead to divergence of stress-energy scalars at the singularities. In the presence of such modes the singularities should remain quasiregular in an exact back-reaction calculation, as confirmed in the colliding gravitational- and electromagnetic-wave spacetime of Chandrasekhar and Xanthopoulos.
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.
Effects of Electromagnetic Field on Gravitational Collapse
M. Sharif; G. Abbas
2009-05-16
In this paper, the effect of electromagnetic field has been investigated on the spherically symmetric collapse with the perfect fluid in the presence of positive cosmological constant. Junction conditions between the static exterior and non-static interior spherically symmetric spacetimes are discussed. We study the apparent horizons and their physical significance. It is found that electromagnetic field reduces the bound of cosmological constant by reducing the pressure and hence collapsing process is faster as compared to the perfect fluid case. This work gives the generalization of the perfect fluid case to the charged perfect fluid. Results for the perfect fluid case are recovered.
Electromagnetic response of closely spaced metal meshes
NASA Astrophysics Data System (ADS)
Taylor, Melita C.; Hibbins, Alastair P.; Sambles, J. Roy
2012-07-01
The electromagnetic transmittance of a double layer of identical square arrays of square holes (mesh) in a perfectly conducting sheet is analytically modeled using a modal matching technique. The structure supports families of standing-wave modes together with surface modes that, close to the onset of diffraction, interact with each other. For frequencies below the onset of diffraction, it is the strength of this interaction mediated by evanescent diffraction in the near fields that dictates the electromagnetic response, which is studied as a function of mesh separation and the lateral misalignment between the meshes.
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.
Classical quarks in dual electromagnetic fields
Harry Schiff
2010-12-05
Electromagnetic properties of quark-like particles are examined in a classical field model involving extended dual electromagnetic fields. These can have fractional charges and a confining potential that derives essentially completely from a short-range weaker potential. The combined potentials exhibit an asymptotically free spherical surface and contribute to the masses of the particles. The quarks are shown to have an intrinsic symmetry that describes their structures in hadrons. Multi- quark solutions are easily obtained for both stable and unstable particles. Each quark can undergo simple harmonic motion in a range of frequencies.
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 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.
Hawking radiation in an electromagnetic waveguide?
Schützhold, Ralf; Unruh, William G
2005-07-15
It is demonstrated that the propagation of electromagnetic waves in an appropriately designed waveguide is (for large wavelengths) analogous to that within a curved space-time--such as around a black hole. As electromagnetic radiation (e.g., microwaves) can be controlled, amplified, and detected (with present-day technology) much easier than sound, for example, we propose a setup for the experimental verification of the Hawking effect. Apart from experimentally testing this striking prediction, this would facilitate the investigation of the trans-Planckian problem. PMID:16090733
Optimization design of electromagnetic shielding composites
NASA Astrophysics Data System (ADS)
Qu, Zhaoming; Wang, Qingguo; Qin, Siliang; Hu, Xiaofeng
2013-03-01
The effective electromagnetic parameters physical model of composites and prediction formulas of composites' shielding effectiveness and reflectivity were derived based on micromechanics, variational principle and electromagnetic wave transmission theory. The multi-objective optimization design of multilayer composites was carried out using genetic algorithm. The optimized results indicate that material parameter proportioning of biggest absorption ability can be acquired under the condition of the minimum shielding effectiveness can be satisfied in certain frequency band. The validity of optimization design model was verified and the scheme has certain theoretical value and directive significance to the design of high efficiency shielding composites.
Classical quarks in dual electromagnetic fields
Schiff, Harry
2010-01-01
Electromagnetic properties of quark-like particles are examined in a classical field model involving extended dual electromagnetic fields. These can have fractional charges and a confining potential that derives essentially completely from a short-range weaker potential. The combined potentials exhibit an asymptotically free spherical surface and contribute to the masses of the particles. The quarks are shown to have an intrinsic symmetry that describes their structures in hadrons. Multi- quark solutions are easily obtained for both stable and unstable particles. Each quark can undergo simple harmonic motion in a range of frequencies.
Electromagnetic force on structured metallic surfaces
NASA Astrophysics Data System (ADS)
Velzen, Andrew H.; Webb, Kevin J.
2015-09-01
We present a method by which the relatively weak electromagnetic force exerted on a surface can be dramatically enhanced. By structuring a metal surface at the nanoscale, we show that the force can be substantially increased over that on the planar metallic surface. The basis for this effect is found to be cavity-enhanced fields and the excitation of surface waves, and results are related to theory. In practice, this force enhancement could be expanded to other materials in various frequency regimes. This increased electromagnetic force should facilitate an expansion of applications related to optomechanics.
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.
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.
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.
Micro-electromagnetic formation flight of satellite systems
Sakaguchi, Aya, S.M. Massachusetts Institute of Technology
2007-01-01
Electromagnetic formation flight (EMFF) investigates the concept of using electromagnets to provide the forces to maintain a satellite's relative position in a formation. Thus far, high temperature superconducting (HTS) ...
Electromagnetic Visibility and Invisibility Massachusetts Institute of Technology
Ciocan-Fontanine, Ionut
Electromagnetic Visibility and Invisibility Ting Zhou Massachusetts Institute of Technology- tromagnetic waves: visibility and invisibility. The first part concerns visibility, that is the question of determining the internal properties of a medium by mak- ing electromagnetic measurements at the boundary
THE ELECTROMAGNETIC INVERSE SCATTERING PROBLEM FOR PARTIALLY COATED LIPSCHITZ DOMAINS
Cakoni, Fioralba
THE ELECTROMAGNETIC INVERSE SCATTERING PROBLEM FOR PARTIALLY COATED LIPSCHITZ DOMAINS FIORALBA CAKONI, DAVID COLTON AND PETER MONK Abstract. We consider the inverse scattering problem of determining method. Key words. Electromagnetic inverse scattering, Lipschitz domain, mixed boundary conditions
Understanding Electromagnetic Radiation from an Accelerated William E. Baylis
Understanding Electromagnetic Radiation from an Accelerated Charge William E. Baylis Physics and solid theoretical underpinnings, the formation of electromagnetic (EM) radiation by accelerating charges is still a source of wonder if not bewilderment. The con- ceptual understanding of how radiation
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 ...
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.
Accurate Estimation of Electromagnetic Wave Extinction through Foliage
Sarabandi, Kamal
Accurate Estimation of Electromagnetic Wave Extinction through Foliage Feinian Wang Radiation the phase and extinction matrices. The second approach, based on wave theory, uses Foldy's approximation [2 for estimation of electromagnetic wave extinction in forested environment over long distances.
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
Fractional Diffusion Modeling of Electromagnetic Induction in Fractured Rocks
Ge, Jianchao
2014-08-11
The controlled-source electromagnetic (CSEM) technique is well-established for non-invasive geophysical survey. Due to the strong attenuation of earth materials to electromagnetic signals, the effective depth of most CSEM surveys is restricted to 1...
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
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
Connors, Daniel A.
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
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.
Electromagnetic properties of viscous charged fluids
NASA Astrophysics Data System (ADS)
Forcella, Davide; Zaanen, Jan; Valentinis, Davide; van der Marel, Dirk
2014-07-01
We provide a general theoretical framework to describe the electromagnetic properties of viscous charged fluids, consisting, for example, of electrons in certain solids or plasmas. We confirm that finite viscosity leads to multiple modes of evanescent electromagnetic waves at a given frequency, one of which is characterized by a negative index of refraction, as previously discussed in a simplified model by one of the authors. In particular, we explain how optical spectroscopy can be used to probe the viscosity. We concentrate on the impact of this on the coefficients of refraction and reflection at the sample-vacuum interface. Analytical expressions are obtained relating the viscosity parameter to the reflection and transmission coefficients of light. We demonstrate that finite viscosity has the effect to decrease the reflectivity of a metallic surface, while the electromagnetic field penetrates more deeply. While on a phenomenological level there are similarities to the anomalous skin effect, the model presented here requires no particular assumptions regarding the corpuscular nature of the charge liquid. A striking consequence of the branching phenomenon into two degenerate modes is the occurrence in a half-infinite sample of oscillations of the electromagnetic field intensity as a function of distance from the interface.
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…
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.
Image analysis for realistic electromagnetic imaging systems
Popovic, Zoya
the image qual- ity and processing requirements: high data dimensionality; low signal-to-noise ratio;· manifold learning and classification, applied to epilepsy detection, multispectral IR and THz imagingImage analysis for realistic electromagnetic imaging systems by Mabel Delice R´amirez V´elez B
New variables for gyrokinetic electromagnetic simulations
Mishchenko, Alexey Cole, Michael; Kleiber, Ralf; Könies, Axel
2014-05-15
A new approach to electromagnetic gyrokinetic simulations based on modified gyrokinetic theory is described. The method is validated using a particle-in-cell code. The Toroidal Alfvén Eigenmode at low perpendicular mode numbers, the so-called “magnetohydrodynamical limit,” has been successfully simulated using this method.
Pullback transformation in gyrokinetic electromagnetic simulations
Mishchenko, Alexey Könies, Axel; Kleiber, Ralf; Cole, Michael
2014-09-15
It is shown that a considerable mitigation of the cancellation problem can be achieved by a slight modification of the simulation scheme. The new scheme is verified, simulating a Toroidal Alfvén Eigenmode in tokamak geometry at low perpendicular mode numbers, the so-called “MHD limit.” Also, an electromagnetic drift mode has been successfully simulated in a stellarator.
Relativistic Motion in a Constant Electromagnetic Field
Siu A. Chin
2008-09-04
For a relativistic charged particle moving in a constant electromagnetic field, its velocity 4-vector has been well studied. However, despite the fact that both the electromagnetic field and the equations of motion are purely real, the resulting 4-velocity is seemingly due to a complex electromagnetic field. This work shows that this is not due to some complex formalism used (such as Clifford algebra) but is intrinsically due to the fact that the $o(3,1)$ Lie algebra of the Lorentz group is equivalent to two commuting complex $su(2)$ algebras. Expressing the complex $su(2)$ generators in terms of the boost and rotation operators then naturally introduces a complex electromagnetic field. This work solves the equation of motion not as a matrix equation, but as an operator evolution equation in terms of the generators of the Lorentz group. The factorization of the real evolution operator into two commuting complex evolution operators then directly gives the time evolution of the velocity 4-vector without any reference to an intermediate field.
Strangeness Electromagnetic Production on Nucleons and Nuclei
Petr Bydzovsky; Miloslav Sotona
2009-12-02
Isobar models for the electromagnetic production of kaons are discussed with emphasis on the K^+ photoproduction at very small kaon angles and K^0 photoproduction on deuteron. Distorted-wave impuls approximation calculations of the cross sections for the electroproduction of hypernuclei are presented on the case of the ^{12}B_\\Lambda production.
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.
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.
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.
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.
Nucleon electromagnetic form factors in QCD
Aliev, T. M.; Azizi, K.; Ozpineci, A.; Savci, M.
2008-06-01
The nucleon electromagnetic form factors are calculated in a light cone QCD sum rules framework using the most general form of the nucleon interpolating current. Using two models for the distribution amplitudes, we predict the form factors. The predictions are also compared with existing experimental data. It is shown that our results describe remarkably well the existing experimental data.
A Simple Method for Generating Electromagnetic Oscillations
Vyacheslav Buts; Dmitriy Vavriv; Oleg Nechayev; Dmitriy Tarasov
2013-08-23
We propose a novel approach to the generation of electromagnetic oscillations by means of a low-frequency pumping of two coupled linear oscillators. A theory of such generation mechanism is proposed, and its feasibility is demonstrated by using coupled RLC oscillators. A comparison of the theoretical results and the experimental data is presented.
Accuracy Assessment for AG500, Electromagnetic Articulograph
ERIC Educational Resources Information Center
Yunusova, Yana; Green, Jordan R.; Mefferd, Antje
2009-01-01
Purpose: The goal of this article was to evaluate the accuracy and reliability of the AG500 (Carstens Medizinelectronik, Lenglern, Germany), an electromagnetic device developed recently to register articulatory movements in three dimensions. This technology seems to have unprecedented capabilities to provide rich information about time-varying…
Electromagnetic waves in a wormhole geometry
NASA Astrophysics Data System (ADS)
Perez Bergliaffa, S. E.; Hibberd, K. E.
2000-08-01
We investigate the propagation of electromagnetic waves through a static wormhole. It is shown that the problem can be reduced to a one dimensional Schrödinger-like equation with a barrier-type potential. Using numerical methods, we calculate the transmission coefficient as a function of the energy. We also discuss the polarization of the outgoing radiation due to this gravitational scattering.
-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
Slave Electromagnetic studies Alan G. Jones1
Jones, Alan G.
Slave Electromagnetic studies Alan G. Jones1 , Ian J. Ferguson2 , Alan D. Chave3 , Rob Evans4, New York 13244, USA. Email: jespratt@syr.edu The Archean Slave craton is an ideal natural laboratory to determine the eastern lateral extent of the central Slave mantle conductor (CSMC) defined by the other
Electromagnetic field interactions with biological systems
Frey, A.H. )
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.
LEAST-SQUARES METHODS FOR COMPUTATIONAL ELECTROMAGNETICS
Ewing, Richard E.
as to style and content by: James H. Bramble (Co-Chair of Committee) Joseph E. Pasciak (Co-Chair of CommitteeÂChairs of Advisory Committee: Dr. James H. Bramble Dr. Joseph E. Pasciak The modeling of electromagnetic phenomena to my advisors, Professors James Bramble and Joseph Pasciak. They showed me what it means
Composite Vector Particles in External Electromagnetic Fields
Zohreh Davoudi; William Detmold
2015-10-08
Lattice quantum chromodynamics (QCD) studies of electromagnetic properties of hadrons and light nuclei, such as magnetic moments and polarizabilities, have proven successful with the use of background field methods. With an implementation of nonuniform background electromagnetic fields, properties such as charge radii and higher electromagnetic multipole moments (for states of higher spin) can be additionally obtained. This can be achieved by matching lattice QCD calculations to a corresponding low-energy effective theory that describes the static and quasi-static response of hadrons and nuclei to weak external fields. With particular interest in the case of vector mesons and spin-1 nuclei such as the deuteron, we present an effective field theory of spin-1 particles coupled to external electromagnetic fields. To constrain the charge radius and the electric quadrupole moment of the composite spin-1 field, the single-particle Green's functions in a linearly varying electric field in space are obtained within the effective theory, providing explicit expressions that can be used to match directly onto lattice QCD correlation functions. The viability of an extraction of the charge radius and the electric quadrupole moment of the deuteron from the upcoming lattice QCD calculations of this nucleus is discussed.
Quantized electromagnetic tornado in pulsar vacuum gap
Kontorovich, V M
2009-01-01
The solution for the electromagnetic tornado in a vacuum gap of a pulsar that could serve as an explanation of the observed circular polarization of giant pulses from pulsars and might also explain the frequency strips observed in giant pulses spectrum is found.
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
Structural composites with integrated electromagnetic functionality
Nemat-Nasser, Sia
, these electro- magnetic effective media can provide controlled response to electromagnetic radiation such as RF communication signals, radar, and/or infrared radiation. With the addition of dynamic components, these materials may be leveraged for active tasks such as filtering. The advantages of such hybrid composites
Linear Electromagnetic Acutator With Manual Override
NASA Technical Reports Server (NTRS)
Abel, Stephen G.
1994-01-01
Conceptual permanent-magnet-assisted electromagnetic linear actuator used to set axial position of metering component in valve. One notable feature of actuator is external pole-piece subassembly that swivels manually about axis of linear motion (which is also axis of cylindrical symmetry) to vary distribution of magnetic flux in such way as to override electrical position control. Armature and magnets hermetically sealed.
Generalized Electromagnetic fields in Chiral Medium
P. S. Bisht; Jivan Singh; O. P. S. Negi
2007-03-12
The time dependent Dirac-Maxwell's Equations in presence of electric and magnetic sources are written in chiral media and the solutions for the classical problem are obtained in unique simple and consistent manner. The quaternion reformulation of generalized electromagnetic fields in chiral media has also been developed in compact, simple and consistent manner.
Electromagnetic Composites at the Compton Scale
NASA Astrophysics Data System (ADS)
Mayer, Frederick J.; Reitz, John R.
2012-01-01
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.
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…
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.
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.
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...
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.
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)
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.…
Theory of electromagnetic reactions in light nuclei
Tianrui Xu; Mirko Miorelli; Sonia Bacca; Gaute Hagen
2015-09-11
We briefly review the theory for electromagnetic reactions in light nuclei based on the coupled-cluster formulation of the Lorentz integral transform method. Results on photodisintegration reactions of 22O and 40Ca are reported on and preliminary calculations on the Coulomb sum rule for 4He are discussed.
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.
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,…
Electromagnetic Scattering from Foliage Camouflaged Hard Targets,
Sarabandi, Kamal
Electromagnetic Scattering from Foliage Camouflaged Hard Targets, in VHF-band Mojtaba Dehmollaian@eecs.umich.edu Abstract A hybrid target-foliage model is developed to investigate the scattering be- havior of hard on single scattering theory for propagation through and scattering from the forest [1] and an FDTD technique
Inverse design of cooperative electromagnetic interactions
Langlais, Mathieu; Besbes, Mondher; Ben-Abdallah, Philippe
2013-01-01
The cooperative electromagnetic interactions between discrete resonators have been widely used to modify the optical properties of metamaterials. Here we propose a general evolutionary approach for engineering these interactions in arbitrary networks of resonators. To illustrate the performances of this approach, we designed by genetic algorithm, an almost perfect broadband absorber in the visible range made with a simple binary array of metallic nanoparticles.
Electromagnetic bubbles: subcycle near-femtosecond
Kaplan, Alexander
-femtosecond or even sub- femtosecond) subcycle (nonoscillating) electromagnetic solitons [EM bubbles (EMB's)] in a gas of two-level at- oms as well as EMB's and preionization shock waves in classically nonlinear atoms. We show that EMB's can be generated by existing sources of radiation, including subpicosecond half
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.
Electromagnetic interaction in the theory of straight strings
Nikitin, I.N.; Pron`ko, G.P.
1995-06-01
A scheme is proposed for including electromagnetic interaction into the theories of stretched relativistic objects. In the theory of the straight string, the operator of electromagnetic interaction is constructed, and form factors of electromagnetic transitions are calculated. 6 refs., 1 fig.
Pre-metric electromagnetism as a path to unification
Delphenich, David
2015-01-01
It is shown that the pre-metric approach to Maxwell's equations provides an alternative to the traditional Einstein-Maxwell unification program, namely, that electromagnetism and gravitation are unified in a different way that makes the gravitational field a consequence of the electromagnetic constitute properties of spacetime, by way of the dispersion law for the propagation of electromagnetic waves.
Design and development report EJSM Electro-Magnetic Sensor Study
Aulanier, Guillaume
Design and development report EJSM Electro-Magnetic Sensor Study Authors: B. Cecconi, J-31028 Toulouse cedex, France Date: Sept. 1st, 2010 Version: 1.7 09/01/2010 EJSM ElectroMagnetic Sensor and Magnetic Signals! 15 09/01/2010 EJSM ElectroMagnetic Sensor Study Report 2 #12
ARTICULATORY SPACE CALIBRATION IN 3D ELECTRO-MAGNETIC ARTICULOGRAPHY
Johnson, Michael T.
ARTICULATORY SPACE CALIBRATION IN 3D ELECTRO-MAGNETIC ARTICULOGRAPHY An Ji1 , Michael T. Johnson1 method to calibrate data collected using Electro-Magnetic Articulography (EMA) into an appropriate of articulatory kinematics and relationship to acoustics. Index Terms-- Electro-Magnetic Articulography
Electromagnetic Crack Detection Inverse Problems using Terahertz Interrogating Signals
Electromagnetic Crack Detection Inverse Problems using Terahertz Interrogating Signals H. T. Banks formulation to determine characteristics of a defect from a perturbed electromagnetic interrogating signal of the interfaces, of the windowed interrogating signal. We model the electromagnetic waves inside the material
Electromagnetic wave scattering by small perfectly conducting particles and applications
Electromagnetic wave scattering by small perfectly conducting particles and applications A. G. Ramm by a single electromagnetic far-field measurement J. Math. Phys. 50, 123506 (2009); 10.1063/1.3263140 Scattering of electromagnetic waves in metamaterial superlattices Appl. Phys. Lett. 90, 201919 (2007); 10
OPTIMIZATION OF THE SHAPE OF AN ELECTROMAGNET: REGULARITY RESULTS
Ring, Wolfgang
OPTIMIZATION OF THE SHAPE OF AN ELECTROMAGNET: REGULARITY RESULTS G.H. PEICHL \\Lambda AND W. RING'echet differentiability of a shape func tional arising in the optimal shape design of an electromagnet. 1. Introduction The optimization of the shape of an electromagnet is one of the classical problems in shape optimization which has
OPTIMIZATION OF THE SHAPE OF AN ELECTROMAGNET: REGULARITY RESULTS
Ring, Wolfgang
OPTIMIZATION OF THE SHAPE OF AN ELECTROMAGNET: REGULARITY RESULTS G.H. PEICHL AND W. RING Abstract func- tional arising in the optimal shape design of an electromagnet. 1. Introduction The optimization of the shape of an electromagnet is one of the classical problems in shape optimization which has been
OPTIMIZATION OF THE SHAPE OF AN ELECTROMAGNET: REGULARITY RESULTS
Peichl, Gunther Helmut
OPTIMIZATION OF THE SHAPE OF AN ELECTROMAGNET: REGULARITY RESULTS G.H. Peichl y and W. Ring y'echet differentiability of a shape functional arising in the optimal shape design of an electromagnet. 1.Introduction The optimization of the shape of an electromagnet is one of the classical problems in shape optimization. It has
3D MODELLING OF ELECTROMAGNETIC INDUCTION IN THE EARTH'S MANTLE
Cerveny, Vlastislav
3D MODELLING OF ELECTROMAGNETIC INDUCTION IN THE EARTH'S MANTLE Tests of sensitivity to the 3D-scale electromagnetic induction in a heterogeneous conducting sphere is used to test the sensitivity of the response The inverse problem of electromagnetic induction was restricted to the 1D radial conductivity models
Pre-Metric Electromagnetism as a Path to Unification
NASA Astrophysics Data System (ADS)
Delphenich, David
It is shown that the pre-metric approach to Maxwell's equations provides an alternative to the traditional Einstein- Maxwell unification problem, namely, that electromagnetism and gravitation are unified in a different way that makes the gravitational field a consequence of the electromagnetic constitutive properties of spacetime, by way of the dispersion law for the propagation of electromagnetic waves.
ELECTROMAGNETIC IMAGES OF THE TINTINA FAULT (NORTHERN CANADIAN CORDILLERA)
Jones, Alan G.
ELECTROMAGNETIC IMAGES OF THE TINTINA FAULT (NORTHERN CANADIAN CORDILLERA) Juanjo Ledo1 , Alan G to obtain a crustal scale electromagnetic image of the fault. A short, higher station density profile-dimensional (2- D) electromagnetic behavior of the fault. Distortion decomposition of the responses corroborated
Electromagnetic modes in periodically structured A Scattering Approach
Electromagnetic modes in periodically structured cavities A Scattering Approach Paul S. Davids1 1 Force is a vacuum fluctuation driven force in an electromagnetic cavity. Paul S. Davids (Sandia in an electromagnetic cavity. Macroscopic manifestation of quantum electrodynamics. Paul S. Davids (Sandia) Scattering
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
Pre-metric electromagnetism as a path to unification
David Delphenich
2015-12-16
It is shown that the pre-metric approach to Maxwell's equations provides an alternative to the traditional Einstein-Maxwell unification program, namely, that electromagnetism and gravitation are unified in a different way that makes the gravitational field a consequence of the electromagnetic constitute properties of spacetime, by way of the dispersion law for the propagation of electromagnetic waves.
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
Electromagnetically Induced Guiding of Counter-Propagating Lasers in Plasmas
Electromagnetically Induced Guiding of Counter-Propagating Lasers in Plasmas G. Shvets Princeton guiding length. This phenomenon of electromagnetically-induced guiding can be utilized in laser diraction due to its nonlinear interaction with another, counter-propagating pulse. Such electromagnetically
Designing tokamaks to withstand electromagnetic disruption loads
NASA Astrophysics Data System (ADS)
Crowell, Jeffrey Arnold
1999-11-01
Tokamaks, the toroidal plasma confinement devices used to study fusion energy, operate by driving a multi-MA current in the plasma while creating a strong confining magnetic field. In experimental tokamaks under some conditions, the plasma can become unstable, escape its magnetic confines and rapidly cool off. On a time scale of milliseconds, the plasma current decays away in the resulting cold and highly resistive plasma. In these events, called disruptions, the rapid change in plasma current induces large currents in the surrounding conducting structures. The induced currents, flowing in the presence of a strong magnetic field, can apply substantial electromagnetic forces. Some experimental devices, such as the JET facility, have experienced extensive damage from these events. In future power reactors, even greater loads must be absorbed by components also subject to neutron embrittlement. This study models the electromagnetic and structural behavior of conceptual designs of the first generation of power-producing tokamaks to identify the components that are at risk and illuminate design options which mitigate these loads. The problem is a coupled one: the geometry and resistivity of the structure affects the induced currents while the induced currents and resulting loads place demands on the structure. Several new analytical and computational tools for the evaluation of these systems are discussed including a dual-solution technique for taking advantage of the complex electromagnetic symmetries in a typical tokamak design. The finite element method with a differential formulation and an integral method using a Green's function have been applied to 2D and 3D electromagnetic models of tokamaks. The differential formulation was found to be superior in these highly symmetric systems. The most significant design issues arise with the components most proximate to the plasma. Despite toroidal segmentation, damaging electromagnetic loads threaten the first wall and blanket structures. Supporting these against disruption loads without causing excessive thermal stress is a significant design challenge.
Florida, University of
of Lightning-Radiated Electromagnetic Fields in the Vicinity of Lossy Ground Abdolhamid Shoory, Rouzbeh Moini theory (AT) approach in the frequency domain is presented to compute electromagnetic fields radiated ground, method of moments (MoM). I. INTRODUCTION INTERACTION of lightning-radiated electromagnetic fields
Electronic systems failures and anomalies attributed to electromagnetic interference
NASA Technical Reports Server (NTRS)
Leach, R. D. (editor); Alexander, M. B. (editor)
1995-01-01
The effects of electromagnetic interference can be very detrimental to electronic systems utilized in space missions. Assuring that subsystems and systems are electrically compatible is an important engineering function necessary to assure mission success. This reference publication will acquaint the reader with spacecraft electronic systems failures and anomalies caused by electromagnetic interference and will show the importance of electromagnetic compatibility activities in conjunction with space flight programs. It is also hoped that the report will illustrate that evolving electronic systems are increasingly sensitive to electromagnetic interference and that NASA personnel must continue to diligently pursue electromagnetic compatibility on space flight systems.
A strong permanent magnet-assisted electromagnetic undulator
Halbach, K.
1987-01-30
This invention discloses an improved undulator comprising a plurality of electromagnet poles located along opposite sides of a particle beam axis with alternate north and south poles on each side of the beam to cause the beam to wiggle or undulate as it travels generally along the beam axis and permanent magnets spaced adjacent the electromagnetic poles on each side of the axis of said particle beam in an orientation sufficient to reduce the saturation of the electromagnet poles whereby the field strength of the electromagnet poles can be increased beyond the normal saturation levels of the electromagnetic poles. 4 figs.
A new adaptive hybrid electromagnetic damper: modelling, optimization, and experiment
NASA Astrophysics Data System (ADS)
Asadi, Ehsan; Ribeiro, Roberto; Behrad Khamesee, Mir; Khajepour, Amir
2015-07-01
This paper presents the development of a new electromagnetic hybrid damper which provides regenerative adaptive damping force for various applications. Recently, the introduction of electromagnetic technologies to the damping systems has provided researchers with new opportunities for the realization of adaptive semi-active damping systems with the added benefit of energy recovery. In this research, a hybrid electromagnetic damper is proposed. The hybrid damper is configured to operate with viscous and electromagnetic subsystems. The viscous medium provides a bias and fail-safe damping force while the electromagnetic component adds adaptability and the capacity for regeneration to the hybrid design. The electromagnetic component is modeled and analyzed using analytical (lumped equivalent magnetic circuit) and electromagnetic finite element method (FEM) (COMSOL® software package) approaches. By implementing both modeling approaches, an optimization for the geometric aspects of the electromagnetic subsystem is obtained. Based on the proposed electromagnetic hybrid damping concept and the preliminary optimization solution, a prototype is designed and fabricated. A good agreement is observed between the experimental and FEM results for the magnetic field distribution and electromagnetic damping forces. These results validate the accuracy of the modeling approach and the preliminary optimization solution. An analytical model is also presented for viscous damping force, and is compared with experimental results The results show that the damper is able to produce damping coefficients of 1300 and 0-238 N s m-1 through the viscous and electromagnetic components, respectively.
Electromagnetic model for propagation through clouds
NASA Astrophysics Data System (ADS)
Seker, S. S.
Electromagnetic propagation through a sparse distribution of lossy dielectric particles in a cloud is investigated. A mathematical model is developed to aid in the interpretation of the interaction data obtained by electromagnetic remote probing of mixed ice crystal and waterdrop clouds. Such clouds can contain many possible crystal forms, most notably thin long cylinder, bullets, and flat plate crystals. Bistatic reflectivity and attenuation are computed for waves of selected polarizations passing through clouds with specified size, shape, and distributions. The proposed formulation is matrix and stochastic in nature, and easily accomodates arbitrary polarization states. It allows complete characterization of medium depolarization effects from hydrometers (e.g., attenuation, isolation, and shape shift). The results obtained are of interest in connection with the study of the effects of clouds on microwave or millimeter-wave communications.
Measurements of electromagnetic bias in radar altimetry
NASA Technical Reports Server (NTRS)
Melville, W. K.; Kong, J. A.; Arnold, D. V.; Stewart, R. H.; Keller, W. C.
1991-01-01
As the accuracy of satellite altimetric measurements of sea level is limited in part by the influence of ocean waves on the altimeter signal reflected from the sea surface, the difference between the mean reflecting surface and mean sea level is the electromagnetic bias. In order to obtain a better understanding of this bias, it is measured directly utilizing a 14-GHz scatterometer on the Chesapeake Bay Light Tower. It is shown that electromagnetic bias in radar altimetry may be reduced to the level required by the TOPEX/Poseidon mission utilizing only altimetric data. The mean value of beta, its variability, and the sensitivity to wind are all significantly larger than earlier measurements utilizing a 39-GHz radar carried on a low-flying aircraft.
Algorithm for muon electromagnetic shower reconstruction
S. Mangano; for the Antares collaboration
2007-11-20
The ANTARES neutrino telescope is presently being built in the Mediterranean Sea at a depth of 2500 m. The primary aim of the experiment is the detection of high energy cosmic muon neutrinos, which are identified by the muons that are produced in charged current interactions. These muons are detected by measuring the Cerenkov light which they emit traversing the detector. Sometimes a high momentum muon produces electromagnetic showers. The subject of this paper is a method to reconstruct these showers which includes several steps: an algorithm for the fit of the muon track parameters, preselection of detected photons belonging to a shower, and a final fit with the preselected detected photons to calculate the electromagnetic shower position. Finally a comparison between data obtained with that part of the detector that is currently in operation and simulations is presented.
The Linear Bicharacteristic Scheme for Electromagnetics
NASA Technical Reports Server (NTRS)
Beggs, John H.
2001-01-01
The upwind leapfrog or Linear Bicharacteristic Scheme (LBS) has previously been implemented and demonstrated on electromagnetic wave propagation problems. This paper extends the Linear Bicharacteristic Scheme for computational electromagnetics to model lossy dielectric and magnetic materials and perfect electrical conductors. This is accomplished by proper implementation of the LBS for homogeneous lossy dielectric and magnetic media and for perfect electrical conductors. Heterogeneous media are modeled through implementation of surface boundary conditions and no special extrapolations or interpolations at dielectric material boundaries are required. Results are presented for one-dimensional model problems on both uniform and nonuniform grids, and the FDTD algorithm is chosen as a convenient reference algorithm for comparison. The results demonstrate that the explicit LBS is a dissipation-free, second-order accurate algorithm which uses a smaller stencil than the FDTD algorithm, yet it has approximately one-third the phase velocity error. The LBS is also more accurate on nonuniform grids.
Electromagnetic baryon form factors from holographic QCD
NASA Astrophysics Data System (ADS)
Kim, Keun-Young; Zahed, Ismail
2008-09-01
In the holographic model of QCD suggested by Sakai and Sugimoto, baryons are chiral solitons sourced by D4 instantons in bulk of size 1/(?)1/2 with ? = g2Nc. We quantize the D4 instanton semiclassically using hbar = 1/(Nc?) and non-rigid constraints on the vector mesons. The holographic baryon is a small chiral bag in the holographic direction with a Cheshire cat smile. The vector-baryon interactions occur at the core boundary of the instanton in D4. They are strong and of order 1/(hbar)1/2. To order hbar0 the electromagnetic current is entirely encoded on the core boundary and vector-meson dominated. To this order, the electromagnetic charge radius is of order ?0. The meson contribution to the baryon magnetic moments sums identically to the core contribution. The proton and neutron magnetic moment are tied by a model independent relation similar to the one observed in the Skyrme model.
Electromagnetic corrections to the zonal flow residual
NASA Astrophysics Data System (ADS)
Pusztai, Istvan; Catto, Peter J.; Parra, Felix I.
2014-10-01
The axisymmetric zonal flow residual calculation in tokamak plasmas is generalized to include electromagnetic perturbations. Instead of imposing magnetic perturbations externally, we formulate and solve a description retaining the fully self-consistent temporal and spatial perturbations in the electric and magnetic fields. Simple expressions for the electrostatic, shear and compressional magnetic residual responses derived provide a fully electromagnetic test of the zonal flow residual in gyrokinetic codes. We find that at ? ~ O (1) the most easily testable quantity is the compressional magnetic perturbation generated by the density perturbation corresponding to the zonal flow potential, while at small values of ?, the electrostatic and shear magnetic responses to an initial compressional magnetic perturbation can also be detectable. Without collisions any initial magnetic perturbation remain completely undamped. Supported by US Department of Energy grant at DE-FG02-91ER-54109 at MIT. IP is supported by the International Postdoc grant of Vetenskapsradet.
Electromagnetic detection of a perfect carpet cloak.
Shi, Xihang; Gao, Fei; Lin, Xiao; Zhang, Baile
2015-01-01
It has been shown that a spherical invisibility cloak originally proposed by Pendry et al. can be electromagnetically detected by shooting a charged particle through it, whose underlying mechanism stems from the asymmetry of transformation optics applied to motions of photons and charges [PRL 103, 243901 (2009)]. However, the conceptual three-dimensional invisibility cloak that exactly follows specifications of transformation optics is formidably difficult to implement, while the simplified cylindrical cloak that has been experimentally realized is inherently visible. On the other hand, the recent carpet cloak model has acquired remarkable experimental development, including a recently demonstrated full-parameter carpet cloak without any approximation in the required constitutive parameters. In this paper, we numerically investigate the electromagnetic radiation from a charged particle passing through a perfect carpet cloak and propose an experimentally verifiable model to demonstrate symmetry breaking of transformation optics. PMID:25997798
Electromagnetic Detection of a Perfect Carpet Cloak
NASA Astrophysics Data System (ADS)
Shi, Xihang; Gao, Fei; Lin, Xiao; Zhang, Baile
2015-05-01
It has been shown that a spherical invisibility cloak originally proposed by Pendry et al. can be electromagnetically detected by shooting a charged particle through it, whose underlying mechanism stems from the asymmetry of transformation optics applied to motions of photons and charges [PRL 103, 243901 (2009)]. However, the conceptual three-dimensional invisibility cloak that exactly follows specifications of transformation optics is formidably difficult to implement, while the simplified cylindrical cloak that has been experimentally realized is inherently visible. On the other hand, the recent carpet cloak model has acquired remarkable experimental development, including a recently demonstrated full-parameter carpet cloak without any approximation in the required constitutive parameters. In this paper, we numerically investigate the electromagnetic radiation from a charged particle passing through a perfect carpet cloak and propose an experimentally verifiable model to demonstrate symmetry breaking of transformation optics.
Electromagnetic Detection of a Perfect Carpet Cloak
Shi, Xihang; Gao, Fei; Lin, Xiao; Zhang, Baile
2015-01-01
It has been shown that a spherical invisibility cloak originally proposed by Pendry et al. can be electromagnetically detected by shooting a charged particle through it, whose underlying mechanism stems from the asymmetry of transformation optics applied to motions of photons and charges [PRL 103, 243901 (2009)]. However, the conceptual three-dimensional invisibility cloak that exactly follows specifications of transformation optics is formidably difficult to implement, while the simplified cylindrical cloak that has been experimentally realized is inherently visible. On the other hand, the recent carpet cloak model has acquired remarkable experimental development, including a recently demonstrated full-parameter carpet cloak without any approximation in the required constitutive parameters. In this paper, we numerically investigate the electromagnetic radiation from a charged particle passing through a perfect carpet cloak and propose an experimentally verifiable model to demonstrate symmetry breaking of transformation optics. PMID:25997798
Electromagnetic interactions in quantum Hall ferromagnets
Ray, Rashmi
1998-11-10
The {nu}=1 quantum Hall ground state in materials like GaAs is known to be ferromagnetic in nature. The exchange part of the Coulomb interaction provides the required attractive force to align the electronic spins spontaneously. The gapless Goldstone modes are the angular deviations of the magnetization vector from its fixed ground state orientation. Furthermore, the system supports electrically charged spin skyrmion configurations. It has been claimed in the literature that these skyrmions have half-integral spin owing to the presence of a topological Hopf term in the effective action governing the spin excitations. However, it has also been claimed that the derivation leading to this term is somewhat flawed. In this article, we demonstrate the existence of this term unambiguously. Furthermore, we investigate the electromagnetic interactions of the spin excitations and obtain a compact expression for the leading nonminimal electromagnetic coupling of these degrees of freedom.
Electromagnetic radiation from beam-plasma instabilities
NASA Technical Reports Server (NTRS)
Pritchett, P. L.; Dawson, J. M.
1983-01-01
A computer simulation is developed for the generation of electromagnetic radiation in an electron beam-plasma interaction. The plasma is treated as a two-dimensional finite system, and effects of a continuous nonrelativistic beam input are accounted for. Three momentum and three field components are included in the simulation, and an external magnetic field is excluded. EM radiation generation is possible through interaction among Langmuir oscillations, ion-acoustic waves, and the electromagnetic wave, producing radiation perpendicular to the beam. The radiation is located near the plasma frequency, and polarized with the E component parallel to the beam. The scattering of Langmuir waves caused by ion-acoustic fluctuations generates the radiation. Comparison with laboratory data for the three-wave interactions shows good agreement in terms of the radiation levels produced, which are small relative to the plasma thermal energy.
Classical electromagnetic radiation of the Dirac electron
NASA Technical Reports Server (NTRS)
Lanyi, G.
1973-01-01
A wave-function-dependent four-vector potential is added to the Dirac equation in order to achieve conservation of energy and momentum for a Dirac electron and its emitted electromagnetic field. The resultant equation contains solutions which describe transitions between different energy states of the electron. As a consequence it is possible to follow the space-time evolution of such a process. This evolution is shown in the case of the spontaneous emission of an electromagnetic field by an electron bound in a hydrogen-like atom. The intensity of the radiation and the spectral distribution are calculated for transitions between two eigenstates. The theory gives a self-consistent deterministic description of some simple radiation processes without using quantum electrodynamics or the correspondence principle.
Electromagnetic radiation absorbers and modulators comprising polyaniline
Epstein, Arthur J. (Bexley, OH); Ginder, John M. (Columbus, OH); Roe, Mitchell G. (Columbus, OH); Hajiseyedjavadi, Hamid (Columbus, OH)
1992-01-01
A composition for absorbing electromagnetic radiation, wherein said electromagnetic radiation possesses a wavelength generally in the range of from about 1000 Angstroms to about 50 meters, wherein said composition comprises a polyaniline composition of the formula ##STR1## where y can be equal to or greater than zero, and R.sup.1 and R.sup.2 are independently selected from the group containing of H, --OCH.sub.3, --CH.sub.3, --F, --Cl, --Br, --I, NR.sup.3 .sub.2, --NHCOR.sup.3, --OH, --O.sup.-, SR.sup.3, --OCOR.sup.3, --NO.sub.2, --COOH, --COOR.sup.3, --COR.sup.3, --CHO, and --CN, where R.sup.3 is a C.sub.1 to C.sub.8 alkyl, aryl or aralkyl group.
Does electromagnetic radiation accelerate galactic cosmic rays
NASA Technical Reports Server (NTRS)
Eichler, D.
1977-01-01
The 'reactor' theories of Tsytovich and collaborators (1973) of cosmic-ray acceleration by electromagnetic radiation are examined in the context of galactic cosmic rays. It is shown that any isotropic synchrotron or Compton reactors with reasonable astrophysical parameters can yield particles with a maximum relativistic factor of only about 10,000. If they are to produce particles with higher relativistic factors, the losses due to inverse Compton scattering of the electromagnetic radiation in them outweigh the acceleration, and this violates the assumptions of the theory. This is a critical restriction in the context of galactic cosmic rays, which have a power-law spectrum extending up to a relativistic factor of 1 million.
Nonlinear Electromagnetic Interactions in Energetic Materials
Wood, M A; Moore, D S
2015-01-01
We study the scattering of electromagnetic waves in anisotropic energetic materials. Nonlinear light-matter interactions in molecular crystals result in frequency-conversion and polarization changes. Applied electromagnetic fields of moderate intensity can induce these nonlinear effects without triggering chemical decomposition, offering a mechanism for non-ionizing identification of explosives. We use molecular dynamics simulations to compute such two-dimensional Raman spectra in the terahertz range for planar slabs made of PETN and ammonium nitrate. We discuss third-harmonic generation and polarization-conversion processes in such materials. These observed far-field spectral features of the reflected or transmitted light may serve as an alternative tool for stand-off explosive detection.
Pulsed thrust measurements using electromagnetic calibration techniques
Tang Haibin; Shi Chenbo; Zhang Xin'ai; Zhang Zun; Cheng Jiao
2011-03-15
A thrust stand for accurately measuring impulse bits, which ranged from 10-1000 {mu}N s using a noncontact electromagnetic calibration technique is described. In particular, a permanent magnet structure was designed to produce a uniform magnetic field, and a multiturn coil was made to produce a calibration force less than 10 mN. The electromagnetic calibration force for pulsed thrust measurements was linear to the coil current and changed less than 2.5% when the distance between the coil and magnet changed 6 mm. A pulsed plasma thruster was first tested on the thrust stand, and afterward five single impulse bits were measured to give a 310 {mu}N s average impulse bit. Uncertainty of the measured impulse bit was analyzed to evaluate the quality of the measurement and was found to be 10 {mu}N s with 95% credibility.
Space environment, electromagnetic fields, and circadian rhythm.
Izumi, R; Ishioka, N; Mizuno, K; Goka, T
2001-01-01
Human space activity began in 1961. About 400 persons have gone to space since then, and about 70 of them have stayed more than 1 month. Circadian rhythm and sleep in space have been investigated several times, though the effect of longer stays in space has not been adequately clarified. Electromagnetic fields are different in the space environment, especially in deeper space missions, such as the Moon or Mars, but their effects on human health have rarely been studied. In this article, we summarize the current status of the International Space Station project, study circadian rhythm and sleep in space, investigate electromagnetic fields, and state the necessity for investigating this research field. PMID:11774866
Nonlinear electromagnetic gyrokinetic simulations of tokamak plasmas
NASA Astrophysics Data System (ADS)
Jenko, F.; Dorland, W.
2001-12-01
One of the central physics issues currently targeted by nonlinear gyrokinetic simulations is the role of finite-? effects. The latter change the MHD equilibrium, introduce new dynamical space and time scales, alter and enlarge the zoo of electrostatic microinstabilities and saturation mechanisms, and lead to turbulent transport along fluctuating magnetic field lines. It is shown that the electromagnetic effects on primarily electrostatic microinstabilities are generally weakly or moderately stabilizing. However, the saturation of these modes and hence the determination of the transport level in the quasi-stationary turbulent state can be dominated by nonlinear electromagnetic effects and yield surprising results. Despite this, the induced transport is generally electrostatic in nature well below the ideal ballooning limit.
A general law for electromagnetic induction
Giuliani, Giuseppe
2015-01-01
The definition of the induced $emf$ as the integral over a closed loop of the Lorentz force acting on a unit positive charge leads immediately to a general law for electromagnetic induction phenomena. The general law is applied to three significant cases: moving bar, Faraday's and Corbino's disc. This last application illustrates the contribution of the drift velocity of the charges to the induced $emf$: the magneto-resistance effect is obtained without using microscopic models of electrical conduction. Maxwell wrote down `general equations of electromotive intensity' that, integrated over a closed loop, yield the general law for electromagnetic induction, if the velocity appearing in them is correctly interpreted. The flux of the magnetic field through an arbitrary surface that have the circuit as contour {\\em is not the cause} of the induced $emf$. The flux rule must be considered as a calculation shortcut for predicting the value of the induced $emf$ when the circuit is filiform. Finally, the general law o...
A Connection between Gravitation and Electromagnetism
D. M. Snyder
2000-02-16
It is argued that there is a connection between the fundamental forces of electromagnetism and gravitation. This connection occurs because of: 1) the fundamental significance of the finite and invariant velocity of light in inertial reference frames in the special theory, and 2) the reliance of the general theory of relativity upon the special theory of relativity locally in spacetime. The connection between the fundamental forces of electromagnetism and gravitation follows immediately from these two points. A brief review is provided of: 1) the role of the finite and invariant velocity of light in inertial reference frames in the special theory, and 2) certain fundamental concepts of the general theory, including its reliance on the special theory locally.
Computational modeling of nonlinear electromagnetic phenomena
NASA Technical Reports Server (NTRS)
Goorjian, Peter M.; Taflove, Allen
1992-01-01
A new algorithm has been developed that permits, for the first time, the direct time integration of the full-vector nonlinear Maxwell's equations. This new capability permits the modeling of linear and nonlinear, instantaneous and dispersive effects in the electric polarization material media. Results are presented of first-time calculations in 1D of the propagation and collision of femtosecond electromagnetic solitons that retain the optical carrier.
Nucleon electromagnetic form factors with Wilson fermions
M. Gockeler; Ph. Hagler; R. Horsley; Y. Nakamura; M. Ohtani; D. Pleiter; P. E. L. Rakow; A. Schafer; G. Schierholz; W. Schroers; H. Stuben; J. M. Zanotti
2007-10-11
The nucleon electromagnetic form factors continue to be of major interest for experimentalists and phenomenologists alike. They provide important insights into the structure of nuclear matter. For a range of interesting momenta they can be calculated on the lattice. The limiting factor continues to be the value of the pion mass. We present the latest results of the QCDSF collaboration using gauge configurations with two dynamical, non-perturbatively improved Wilson fermions at pion masses as low as 350 MeV.
Rectangular Pulsed Laser-Electromagnetic Hybrid Accelerator
Kishida, Yoshiaki; Katayama, Masahiro; Horisawa, Hideyuki
2010-10-13
Experimental investigation of impulse-bit and propellant consumption rate, or mass shot, per single pulse discharge was conducted to characterize the thrust performance of the rectangular laser-electromagnetic hybrid acceleration thruster with various propellant materials. From the result, alumina propellant showed significantly superior performance. The largest values of the measured impulse-bit, specific impulse and thrust efficiency were 49 {mu}Nsec, 6,200 sec and 22%, respectively.
Why Ampère did not discover electromagnetic induction
NASA Astrophysics Data System (ADS)
Williams, L. Pearce
1986-04-01
In 1832, after Michael Faraday had announced his discovery of electromagnetic induction, Andre-Marie Ampère claimed that he had actually discovered the induction of one current by another in 1822. In fact, he had, but did not really publish the fact at that time. This article explores the reasons for Ampère's failure to lay claim to a discovery that would have guaranteed him scientific immortality.
Scaling the electromagnetically driven explosive shock simulator
NASA Technical Reports Server (NTRS)
Persh, Robert I.
1987-01-01
A heavy payload electromagnetically driven explosive shock simulator, referred to as EDESS-3, has been assembled and characterized at the Navel research Weapons Center. EDESS-3 is the logical outgrowth of the earlier EDESS 1 and 2 simulator work which explored the use of electrical pulse power technology for the generation of explosive like shocks. The features of the EDESS-3 are presented, and designs for the next generation of EDESS machines are introduced.
Black hole formation by incoming electromagnetic radiation
José M. M. Senovilla
2014-08-18
I revisit a known solution of the Einstein field equations to show that it describes the formation of non-spherical black holes by the collapse of pure electromagnetic monochromatic radiation. Both positive and negative masses are feasible without ever violating the dominant energy condition. The solution can also be used to model the destruction of naked singularities and the evaporation of white holes by emission or reception of light.
Electromagnetic radiation from relativistic nuclear collisions
Charles Gale; Kevin L. Haglin
2003-06-16
We review some of the results obtained in the study of the production of electromagnetic radiation in relativistic nuclear collisions. We concentrate on the emission of real photons and dileptons from the hot and dense strongly interacting phases of the reaction. We examine the contributions from the partonic sector, as well as those from the nonperturbative hadronic sector. We examine the current data, some of the predictions for future measurements, and comment on what has been learnt so far.
Vector resonances and electromagnetic nucleon structure
Williams, R.A.; Krewald, S.; Linen, K. )
1995-02-01
Motivated by new, precise magnetic proton form factor data in the timelike reigon, a hybrid vector meson dominance (hVMD) formalism is employed to investigate the significance of excited vector meson rsonances on electromagnetic nucleon structure. We find that the [rho](1700), [omega](1600), and two previously unobserved states are required to reproduce the local structure seen in the new LEAR data just above the [ital p[bar p
Nonlinear fan instability of electromagnetic waves
Krafft, C.; Volokitin, A.
2010-10-15
This paper studies the linear and nonlinear stages of the fan instability, considering electromagnetic waves of the whistler frequency range interacting resonantly with energetic electron fluxes in magnetized plasmas. The main attention is paid to determine the wave-particle interaction processes that can lead to the excitation of intense electromagnetic waves by nonequilibrium particle distributions involving suprathermal tails, and to explain under what conditions and through what mechanisms they can occur, develop, and saturate. This paper presents and discusses two main processes: (i) the linear fan instability and (ii) the nonlinear process of dynamical resonance merging, which can significantly amplify the energy carried by linearly destabilized waves after they saturate due to particle trapping. This study consists of (i) determining analytically and numerically, for parameters typical of space and laboratory plasmas, the linear growth rates of whistlers excited by suprathermal particle fluxes through the fan instability, as well as the corresponding thresholds and the physical conditions at which the instability can appear, (ii) building a theoretical self-consistent 3D model and a related numerical code for describing the nonlinear evolution of the wave-particle system, and (iii) performing numerical simulations to reveal and characterize the nonlinear amplification process at work, its conditions of development, and its consequences, notably in terms of electromagnetic wave radiation. The simulations show that when the waves have reached sufficient energy levels owing to the linear fan instability, they saturate by trapping particles and due to the complex dynamics of these particles in the electromagnetic fields, the resonant velocities' domains of the waves overlap and merge, meanwhile a strong increase of the wave energy occurs.
Engineering electromagnetic metamaterials and methanol fuel cells
NASA Astrophysics Data System (ADS)
Yen, Tajen
2005-07-01
Electromagnetic metamaterials represent a group of artificial structures, whose dimensions are smaller than subwavelength. Due to electromagnetic metamaterials' collective response to the applied fields, they can exhibit unprecedented properties to fascinate researchers' eyes. For instance, artificial magnetism above terahertz frequencies and beyond, negative magnetic response, and artificial plasma lower than ultraviolet and visible frequencies. Our goal is to engineer those novel properties aforementioned at interested frequency regions and further optimize their performance. To fulfill this task, we developed exclusive micro/nano fabrication techniques to construct magnetic metamaterials (i.e., split-ring resonators and L-shaped resonators) and electric metamaterials (i.e., plasmonic wires) and also employed Taguchi method to study the optimal design of electromagnetic metamaterials. Moreover, by integrating magnetic and electric metamaterials, we have been pursuing to fabricate so-called negative index media---the Holy Grail enables not only to reverse conventional optical rules such as Snell's law, Doppler shift, and Cerenkov radiation, but also to smash the diffraction limit to realize the superlensing effect. In addition to electromagnetic metamaterials, in this dissertation we also successfully miniaturize silicon-based methanol fuel cells by means of micro-electrical-mechanical-system technique, which promise to provide an integrated micro power source with excellent performance. Our demonstrated power density and energy density are one of the highest in reported documents. Finally, based on the results of metamaterials and micro fuel cells, we intend to supply building blocks to complete an omnipotent device---a system with sensing, communication, computing, power, control, and actuation functions.
Metamaterial transparency induced by cooperative electromagnetic interactions
Stewart D. Jenkins; Janne Ruostekoski
2013-05-16
We propose a cooperative asymmetry-induced transparency, CAIT, formed by collective excitations in metamaterial arrays of discrete resonators. CAIT can display a sharp transmission resonance even when the constituent resonators individually exhibit broad resonances. We further show how dynamically reconfiguring the metamaterial allows one to actively control the transparency. While reminiscent of electromagnetically induced transparency, which can be described by independent emitters, CAIT relies on a cooperative response resulting from strong radiative couplings between the resonators.
Electromagnetic or other directed energy pulse launcher
Ziolkowski, Richard W. (Livermore, CA)
1990-01-01
The physical realization of new solutions of wave propagation equations, such as Maxwell's equations and the scaler wave equation, produces localized pulses of wave energy such as electromagnetic or acoustic energy which propagate over long distances without divergence. The pulses are produced by driving each element of an array of radiating sources with a particular drive function so that the resultant localized packet of energy closely approximates the exact solutions and behaves the same.
Velocity damper for electromagnetically levitated materials
Fox, Richard J. (Oak Ridge, TN)
1994-01-01
A system for damping oscillatory and spinning motions induced in an electromagnetically levitated material. Two opposed field magnets are located orthogonally to the existing levitation coils for providing a DC quadrupole field (cusp field) around the material. The material used for generating the DC quadrupole field must be nonconducting to avoid eddy-current heating and of low magnetic permeability to avoid distorting the induction fields providing the levitation.
Velocity damper for electromagnetically levitated materials
Fox, R.J.
1992-12-31
A system for damping oscillatory and spinning motions induced in an electromagnetically levitated material. Two opposed field magnets are located orthogonally to the existing levitation coils for providing a DC quadrupole field (cusp field) around the material. The material used for generating the DC quadrupole field must be nonconducting to avoid eddy-current heating and of low magnetic permeability to avoid distorting the induction fields providing the levitation.
Theory and applications of electromagnetic levitation
NASA Technical Reports Server (NTRS)
Frost, R. T.; Chang, C. W.
1982-01-01
A simple treatment of the electromagnetic levitation problem is presented, with emphasis placed on approximate formulas useful in planning and interpreting laboratory measurements. Consideration is also given to numerical solutions for fields, eddy currents, and Lorentz forces for rapidly varying applied fields, with particular reference made to traveling wave levitation experiments. Applications of levitation processing are briefly reviewed, including thermophysical property measurements, undercooling studies, containerless crystal growth, and continuous casting of cylinders.
Science 101: What Causes Electromagnetic Induction?
ERIC Educational Resources Information Center
Robertson, Bill
2013-01-01
Electromagnetic induction is the technical name for the fact that, when a wire is moved near a magnet or a magnet is moved near a wire, an electric current flows in the wire. Although Bill Robertson honestly admits to not knowing why this happens, he does say that it is possible to get a deeper understanding of what's going on in terms of…
Velocity damper for electromagnetically levitated materials
Fox, R.J.
1994-06-07
A system for damping oscillatory and spinning motions induced in an electromagnetically levitated material is disclosed. Two opposed field magnets are located orthogonally to the existing levitation coils for providing a DC quadrupole field (cusp field) around the material. The material used for generating the DC quadrupole field must be nonconducting to avoid eddy-current heating and of low magnetic permeability to avoid distorting the induction fields providing the levitation. 1 fig.
Electromagnetic pulse and the electric power network
Klein, K.W.; Barnes, P.R.; Zaininger, H.W.
1984-01-01
This paper defines the nuclear electromagnetic pulse (EMP) - electric power system interaction problem. A description of high altitude EMP (HEMP) characteristics, source region EMP (SREMP) characteristics, and magnetohydrodynamics EMP (MHD-EMP) characteristics are presented. The results of initial calculations of EMP induced surges on electric power transmission and distribution lines are presented and compared with lightning induced surges. Potential EMP impacts on electric power systems are discussed, and an overview of the Department of Energy (DOE) EMP research program is presented.
Bobbing and kicks in electromagnetism and gravity
Gralla, Samuel E.; Harte, Abraham I.; Wald, Robert M.
2010-05-15
We study systems analogous to binary black holes with spin in order to gain some insight into the origin and nature of 'bobbing' motion and 'kicks' that occur in this system. Our basic tool is a general formalism for describing the motion of extended test bodies in an external electromagnetic field in curved spacetime and possibly subject to other forces. We first show that bobbing of exactly the type as observed in numerical simulations of the binary black hole system occurs in a simple system consisting of two spinning balls connected by an elastic band in flat spacetime. This bobbing may be understood as arising from the difference between a spinning body's 'lab frame centroid' and its true center of mass, and is purely 'kinematical' in the sense that it will appear regardless of the forces holding two spinning bodies in orbit. Next, we develop precise rules for relating the motion of charged bodies in a stationary external electromagnetic field in flat spacetime with the motion of bodies in a weakly curved stationary spacetime. We then consider the system consisting of two orbiting charges with magnetic dipole moment and spin at a level of approximation corresponding to 1.5 post-Newtonian order. Here we find that considerable amounts of momentum are exchanged between the bodies and the electromagnetic field; however, the bodies store this momentum entirely as ''hidden'' mechanical momentum, so that the interchange does not give rise to any net bobbing. The net bobbing that does occur is due solely to the kinematical spin effect, and we therefore argue that the net bobbing of the electromagnetic binary is not associated with possible kicks. We believe that this conclusion holds in the gravitational case as well.
Smart electromagnetic structures: The neural antenna
NASA Astrophysics Data System (ADS)
Thursby, Michael H.
1993-01-01
Smart electromagnetic structures (SEMS) are defined as structures capable of interacting with their surrounding electromagnetic fields and either influencing the field or sensing and adapting to its presence. A structure is smart when it integrates sensing elements (e.g., antennas), processing elements (neural networks) and control elements (diodes) autonomously. SEMS provide an adaptive electromagnetic (EM) environment for the structure on which they are mounted. The ability to adapt derives from the closed loop nature of the SEMS. The speed of adaptation is determined by the speed of the loop, which is set by the computational elements. Our experiments shown the time required for a response is about fifteen gate delays. The integration of artificial neural processors with tuneable antennas was proposed several years ago by our group. This synergy over the past three years was studied. The control of the operating frequency of a microstrip patch antenna was demonstrated. We believe that ours is a unique program offering great potential for payoff in the area of electromagnetic smart skins. Our main goal in this program was to '...determine the feasibility of a neural network controlled antenna and to quantify the ability of the antenna and the NN to learn to tune automatically to the center frequency of a received signal.' These goals were achieved and spun off neural networks that have application of radar and communications systems. Because of its self adaptability the closed loop neural control of an antenna element, provides the potential for design of an easily manufacturable antenna which is immune to typical siting problems, and is tolerant to moderate external damage.
The electromagnetic model of Gamma Ray Bursts
Maxim Lyutikov
2005-12-13
I describe electromagnetic model of gamma ray bursts and contrast its main properties and predictions with hydrodynamic fireball model and its magnetohydrodynamical extension. The electromagnetic model assumes that rotational energy of a relativistic, stellar-mass central source (black-hole--accretion disk system or fast rotating neutron star) is converted into magnetic energy through unipolar dynamo mechanism, propagated to large distances in a form of relativistic, subsonic, Poynting flux-dominated wind and is dissipated directly into emitting particles through current-driven instabilities. Thus, there is no conversion back and forth between internal and bulk energies as in the case of fireball model. Collimating effects of magnetic hoop stresses lead to strongly non-spherical expansion and formation of jets. Long and short GRBs may develop in a qualitatively similar way, except that in case of long bursts ejecta expansion has a relatively short, non-relativistic, strongly dissipative stage inside the star. Electromagnetic and fireball models (as well as strongly and weakly magnetized fireballs) lead to different early afterglow dynamics, before deceleration time. Finally, I discuss the models in view of latest observational data in the Swift era.
Electromagnetic Compatibility in Nuclear Power Plants
Ewing, P.D.; Kercel, S.W.; Korsah, K.; Wood, R.T.
1999-08-29
Electromagnetic compatibility (EMC) has long been a key element of qualification for mission critical instrumentation and control (I&C) systems used by the U.S. military. The potential for disruption of safety-related I&C systems by electromagnetic interference (EMI), radio-frequency interference (RFI), or power surges is also an issue of concern for the nuclear industry. Experimental investigations of the potential vulnerability of advanced safety systems to EMI/RFI, coupled with studies of reported events at nuclear power plants (NPPs) that are attributed to EMI/RFI, confirm the safety significance of EMC for both analog and digital technology. As a result, Oak Ridge National Laboratory has been engaged in the development of the technical basis for guidance that addresses EMC for safety-related I&C systems in NPPs. This research has involved the identification of engineering practices to minimize the potential impact of EMI/RFI and power surges and an evaluation of the ambient electromagnetic environment at NPPs to tailor those practices for use by the nuclear industry. Recommendations for EMC guidance have been derived from these research findings and are summarized in this paper.
Advanced electromagnetic methods for aerospace vehicles
NASA Technical Reports Server (NTRS)
Balanis, Constantine A.; El-Sharawy, El-Budawy; Hashemi-Yeganeh, Shahrokh; Aberle, James T.; Birtcher, Craig R.
1991-01-01
The Advanced Helicopter Electromagnetics is centered on issues that advance technology related to helicopter electromagnetics. Progress was made on three major topics: composite materials; precipitation static corona discharge; and antenna technology. In composite materials, the research has focused on the measurements of their electrical properties, and the modeling of material discontinuities and their effect on the radiation pattern of antennas mounted on or near material surfaces. The electrical properties were used to model antenna performance when mounted on composite materials. Since helicopter platforms include several antenna systems at VHF and UHF bands, measuring techniques are being explored that can be used to measure the properties at these bands. The effort on corona discharge and precipitation static was directed toward the development of a new two dimensional Voltage Finite Difference Time Domain computer program. Results indicate the feasibility of using potentials for simulating electromagnetic problems in the cases where potentials become primary sources. In antenna technology the focus was on Polarization Diverse Conformal Microstrip Antennas, Cavity Backed Slot Antennas, and Varactor Tuned Circular Patch Antennas. Numerical codes were developed for the analysis of two probe fed rectangular and circular microstrip patch antennas fed by resistive and reactive power divider networks.
Electromagnetic Radiation From The Accelerating Universe
James Timothy Struck
2003-06-27
The acceleration of the expansion of the universe has been argued for by several research groups. If the universe is accelerating and if the universe or some part of the universe has a charge, then there may be electromagnetic radiation produced from the acceleration of the universe since accelerating charges produce electromagnetic radiation. This letter does a thought experiment to ask about the possible characteristics of the radiation from an accelerating universe. A value for the power, or rate of energy flow, of the universe's acceleration is calculated in this letter. A value of the power of the electromagnetic radiation emitted by the universe's acceleration is calculated to be P = 5.99 x 10 -82 Joule/sec or 5.99 x 10 -82 Watts. This value for the power assumes only the charge of an electron as the value for the charge; larger charges would produce much larger rates of energy flow. The letter then reveals what a characteristic of a charged, accelerating universe would be.
Noninvasive Electromagnetic Detection of Bladder Cancer
Cormio, Luigi; Vedruccio, Clarbruno; Leucci, Giorgio; Massenio, Paolo; Di Fino, Giuseppe; Cavaliere, Vincenzo; Carrieri, Giuseppe
2014-01-01
Objectives. Normal and neoplastic human tissues have different electromagnetic properties. This study aimed to determine the diagnostic accuracy of noninvasive electromagnetic detection of bladder cancer (BC) by the tissue-resonance interaction method (TRIM-prob). Patients and Methods. Consecutive patients were referred for cystoscopy because of (i) microscopic or gross hematuria and/or irritative voiding symptoms and (ii) bladder ultrasounds and urinary cytology findings negative or just suspicious of malignancy. Patients were first submitted to TRIM-prob bladder scanning by a single investigator and then to cystoscopy by another investigator blind to TRIM-prob data. Results. In 125 evaluated patients cystoscopy was positive for BC in 47 and negative in the remaining 78; conversely, TRIM-prob bladder scanning was positive for BC in 53 and negative in 72. In particular, TRIM-prob scanning yielded 7 false positives and only one false negative; therefore, its overall sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy were 97.9%, 89.9%, 86.8%, 98.6%, and 93.6%, respectively. Conclusions. TRIM-prob bladder scanning was a simple and quite accurate method for non-invasive electromagnetic detection of BC. If the elevated positive and negative predictive values will be replicated in further well-designed studies, it could be used to screen asymptomatic patients at high risk of BC. PMID:24563795
Nonradiating electromagnetic sources in a nonuniform medium.
Nikolova, Natalia K; Rickard, Yotka S
2005-01-01
Nonradiating electromagnetic sources are sources whose field is identically zero outside of their volume. They are undetectable unless the observation point is in direct contact with them. They are the basis of the theory of source equivalence, which studies the field invariance with respect to source transformations. In this work, we focus on the equivalent source transformations in a nonuniform medium and the implications in the theory of the electromagnetic vector potentials. We identify three types of nonradiating sources. Subsequently, we define the mathematical transformations of the sources, which preserve the field outside of their support (source invariance). We give complimentary expressions, which preserve the field inside the source support as well. We show that the nonuniqueness of the electromagnetic potentials is due to the nonunique solution to the inverse problem. The well known field gauge invariance follows from its source invariance. Also, the gauge-invariant transformation appears to be just one possibility in an infinite set of field-invariant vector-potential representations all related to the respective equivalent source transformations. PMID:15697757
DEF: The Physical Basis of Electromagnetic Propulsion
Pinheiro, Mario J
2015-01-01
The very existence of the physical vacuum provides a framework to propose a general mechanism for propelling bodies through an agency of electromagnetic fields, that seat in that medium. When two sub-systems of a general closed device interact via nonlocal and retarded electromagnetic pulses, it is easily shown that they give a nonzero force, and that only tend to comply with the action-to-reaction force in the limit of instantaneous interactions. The arrangement of sub-systems provide a handy way to optimize the unbalanced EM force with the concept of impedance matching. The general properties of the differential electromagnetic force (DEF) are the following: i) it is proportional to the square of the intensity and to the angular wave frequency $\\omega$; ii) to the space between the sub-systems (although in a non-linear manner); iii) it is inversely proportional to the speed of interaction; iv) when the two sub-systems are out-of-phase, DEF is null. The approach is of interest to practical engineering princi...
Electromagnetic force and torque in ponderable media.
Mansuripur, Masud
2008-09-15
Maxwell's macroscopic equations combined with a generalized form of the Lorentz law of force are a complete and consistent set of equations. Not only are these five equations fully compatible with special relativity, they also conform with conservation laws of energy, momentum, and angular momentum. We demonstrate consistency with the conservation laws by showing that, when a beam of light enters a magnetic dielectric, a fraction of the incident linear (or angular) momentum pours into the medium at a rate determined by the Abraham momentum density, E x H/c(2), and the group velocity V(g) of the electromagnetic field. The balance of the incident, reflected, and transmitted momenta is subsequently transferred to the medium as force (or torque) at the leading edge of the beam, which propagates through the medium with velocity V(g). Our analysis does not require "hidden" momenta to comply with the conservation laws, nor does it dissolve into ambiguities with regard to the nature of electromagnetic momentum in ponderable media. The linear and angular momenta of the electromagnetic field are clearly associated with the Abraham momentum, and the phase and group refractive indices (n(p) and n(g)) play distinct yet definitive roles in the expressions of force, torque, and momentum densities. PMID:18795019
Experiments for electromagnetic levitation in microgravity
NASA Technical Reports Server (NTRS)
Willnecker, R.; Egry, I.
1990-01-01
Containerless processing is a promising research tool for investigating the properties of undercooled melts and their solidification. For conducting samples RF-electromagnetic levitation offers the possibility to obtain large undercoolings by avoiding heterogeneous nucleation at container walls. On earth, however, strong magnetic fields are needed to compensate the gravitational force which imposes a lower limit on the available temperatures and on the accessible undercooling range. Under microgravity conditions the magnetic positioning fields can be minimized and hence, undercooling becomes feasible under ultra-high vacuum conditions and lower temperatures become accessible. In contrast to other undercooling and solidification techniques, electromagnetic levitation allows for diagnostic measurements during the early steps of nucleation and phase selection. Experiments cover a wide field of research topics: nucleation, directional solidification at high velocities, generation of metastable phases, evolution of microstructures, properties of undercooled liquids. Examples from these classes including experiments selected for the IML-2 mission are discussed with emphasis on technical requirements. An overview is given on the German TEMPUS (electromagnetic levitation facility) program.
A general theory of DC electromagnetic launchers
NASA Astrophysics Data System (ADS)
Engel, Thomas G.; Timpson, Erik J.
2015-08-01
The non-linear, transient operation of DC electromagnetic launchers (EMLs) complicates their theoretical understanding and prevents scaling studies and performance comparisons without the aid of detailed numerical models. This paper presents a general theory for DC electromagnetic launchers that has simplified these tasks by identifying critical EML parameters and relationships affecting the EML's voltage, current, and power scaling, as well as its performance and energy conversion efficiency. EML parameters and relationships discussed in this paper include the specific force, the operating mode, the launcher constant, the launcher characteristic velocity, the contact characteristic velocity, the energy conversion efficiency, and the kinetic power and voltage-current scaling relationship. The concepts of the ideal EML, same-scale comparisons, and EML impedance are discussed. This paper defines conditions needed for the EML to operate in the steady-state. A comparison of the general theory with experimental results of several different types of DC (i.e., non-induction) electromagnetic launchers ranging from medium velocity (100's m/s) to high velocity (1000's m/s) is performed. There is good agreement between the general theory and the experimental results.
Comparison between electroglottography and electromagnetic glottography
Titze, Ingo R.; Story, Brad H.; Burnett, Gregory C.; Holzrichter, John F.; Ng, Lawrence C.; Lea, Wayne A.
2000-01-01
Newly developed glottographic sensors, utilizing high-frequency propagating electromagnetic waves, were compared to a well-established electroglottographic device. The comparison was made on four male subjects under different phonation conditions, including three levels of vocal fold adduction (normal, breathy, and pressed), three different registers (falsetto, chest, and fry), and two different pitches. Agreement between the sensors was always found for the glottal closure event, but for the general wave shape the agreement was better for falsetto and breathy voice than for pressed voice and vocal fry. Differences are attributed to the field patterns of the devices. Whereas the electroglottographic device can operate only in a conduction mode, the electromagnetic device can operate in either the forward scattering (diffraction) mode or in the backward scattering (reflection) mode. Results of our tests favor the diffraction mode because a more favorable angle imposed on receiving the scattered (reflected) signal did not improve the signal strength. Several observations are made on the uses of the electromagnetic sensors for operation without skin contact and possibly in an array configuration for improved spatial resolution within the glottis. (c) 2000 Acoustical Society of America.
Electromagnetic damper design using a multiphysics approach
NASA Astrophysics Data System (ADS)
Stabile, Alessandro; Aglietti, Guglielmo S.; Richardson, Guy
2015-04-01
Electromagnetic dampers (EMD) have been widely studied and designed in the control of vibrating structures. Yet, their use for space applications has been almost negligible, due mainly to their high ratio of system mass over damping force produced. The development of shunted circuits, and in particular negative impedances, has allowed higher currents to flow in the device, thus obtaining an increased damping performance. However, the need for a thermal analysis has become crucial in order to evaluate the power and temperature limits of EMDs, and hence allow a more efficient optimization of the whole device. This paper presents a multiphysics Finite Element Analysis (FEA) of an EMD in which the thermal domain is integrated with the electromagnetic and mechanical domains. The influence of the temperature on the device parameters and overall performance in the operative temperature and frequency range of a space mission is shown. It follows a design optimization of an electromagnetic shunted damper for 5-kg SDOF to obtain a second-order filter. In particular, the analytical results are compared with the typical transfer function of a viscoelastic material. This paper demonstrates the feasibility to achieve the same slope of -40 dB/dec while considerably decreasing the magnitude of the characteristic resonance peak of viscoelastic materials.
NASA Astrophysics Data System (ADS)
Gershenzon, Naum; Bambakidis, Gust
2014-05-01
Seismo-electromagnetism (SEM), in general, and lithospheric-atmospheric-ionospheric coupling in particular, continue to attract attention as possible earthquake precursors. Do these phenomena in fact exist? Currently there are no models which can explain a variety of electromagnetic observations before and after seismic events ranging from atmospheric light to electromagnetic field to ionosphere disturbances. Most existing models are qualitative, and quantitative estimates are usually superficial. Here we present the results of calculation of electromagnetic signals generated by modeled mechanical disturbances in the earth's crust. The major known SEM phenomena, namely, tectonomagnetic variations, electrotelluric anomalies, geomagnetic variations in the ultra-low frequency range and electromagnetic emission in the radio frequency range, have been considered. We discuss the conditions under which electro-kinetic, piezo-magnetic and piezo-electric effects could be responsible for SEM. A comparison of estimated values of SEMs with reported field measurements leads to the conclusion that, although these mechanisms may explain some of the observations, the sources of most anomalous SEM phenomena should be relatively close to the detector. In other words, the source of the signal is local, although the source of the mechanical disturbance which activates it, e.g. the epicenter of an earthquake, may be far away.
Oil recovery apparatus using an electromagnetic pump drive
Smith, M.L.
1988-09-06
This patent describes process for pumping a fluid from a subterranean fluid-bearing formation penetrated by a wellbore originating at an earthen surface. The process consists of: (a) positioning an electromagnet in a production tubing within the wellbore such that the electromagnet substantially abuts the tubing to substantially prevent fluid flow between the tubing and electromagnet; (b) positioning a reciprocating pump plunger in the tubing a vertical distance below the electromagnet such that the reciprocating pump plunger substantially abuts the tubing to substantially prevent fluid flow between the tubing and reciprocating pump plunger and such that the fluid occupies a volume in the tubing between the reciprocating pump plunger and electromagnet; (c) energizing the electromagnet by providing an electric current to the electromagnet; (d) drawing the reciprocating pump plunger upward in the tubing by a magnetic attraction between the energized electromagnet and a magnetically attractable member affixed to the reciprocating pump plunger until the electromagnet abuts the magnetically attractable member and the electromagnet mechanically stops an upward movement of the magnetically attractable member, the magnetically attractable member further substantially abutting the tubing to substantially prevent fluid flow between the tubing and magnetically attractable member; (e) displacing the fluid occupying the volume upward relative to the surface by the upward motion of the reciprocating pump plunger.
Saldanha, Pablo L
2010-02-01
It is proposed a natural and consistent division of the momentum of electromagnetic waves in linear, non-dispersive and non-absorptive dielectric and magnetic media into material and electromagnetic parts. The material part is calculated using directly the Lorentz force law and the electromagnetic momentum density has the form epsilon(0)E x B, without an explicit dependence on the properties of the media. The consistency of the treatment is verified through the obtention of a correct momentum balance equation in many examples and showing the compatibility of the division with the Einstein's theory of relativity by the use of a gedanken experiment. An experimental prediction for the radiation pressure on mirrors immersed in linear dielectric and magnetic media is also made. PMID:20174054
Method and apparatus for electromagnetically braking a motor
NASA Technical Reports Server (NTRS)
Davis, Donald R. (Inventor); Radford, Nicolaus A (Inventor); Permenter, Frank Noble (Inventor); Parsons, Adam H (Inventor); Mehling, Joshua S (Inventor)
2011-01-01
An electromagnetic braking system and method is provided for selectively braking a motor using an electromagnetic brake having an electromagnet, a permanent magnet, a rotor assembly, and a brake pad. The brake assembly applies when the electromagnet is de-energized and releases when the electromagnet is energized. When applied the permanent magnet moves the brake pad into frictional engagement with a housing, and when released the electromagnet cancels the flux of the permanent magnet to allow a leaf spring to move the brake pad away from the housing. A controller has a DC/DC converter for converting a main bus voltage to a lower braking voltage based on certain parameters. The converter utilizes pulse-width modulation (PWM) to regulate the braking voltage. A calibrated gap is defined between the brake pad and permanent magnet when the brake assembly is released, and may be dynamically modified via the controller.
Gauge Theory of the Gravitational-Electromagnetic Field
Robert D. Bock
2015-05-26
We develop a gauge theory of the combined gravitational-electromagnetic field by expanding the Poincar\\'e group to include clock synchronization transformations. We show that the electromagnetic field can be interpreted as a local gauge theory of the synchrony group. According to this interpretation, the electromagnetic field equations possess nonlinear terms and electromagnetic gauge transformations acquire a space-time interpretation as local synchrony transformations. The free Lagrangian for the fields leads to the usual Einstein-Maxwell field equations with additional gravitational-electromagnetic coupling terms. The connection between the electromagnetic field and the invariance properties of the Lagrangian under clock synchronization transformations provides a strong theoretical argument in favor of the thesis of the conventionality of simultaneity. This suggests that clock synchronization invariance (or equivalently, invariance under transformations of the one-way speed of light) is a fundamental invariance principle of physics.
Electromagnetic backreaction from currents on a straight string
NASA Astrophysics Data System (ADS)
Wachter, Jeremy M.; Olum, Ken D.
2014-07-01
Charge carriers moving at the speed of light along a straight, superconducting cosmic string carry with them a logarithmically divergent slab of electromagnetic field energy. Thus, no finite local input can induce a current that travels unimpeded to infinity. Rather, electromagnetic backreaction must damp this current asymptotically to nothing. We compute this backreaction and find that the electromagnetic fields and currents decline exactly as rapidly as necessary to prevent a divergence. We briefly discuss the corresponding gravitational situation.
Electromagnetic Field Scattering on rf-SQUID Based Metasurfaces
NASA Astrophysics Data System (ADS)
Raputo, J. G.; Gabitov, I. R.; Kudyshev, Zh.; Kupaev, T.; Maimistov, A. I.
2015-09-01
Electromagnetic field scattering on a 2D array of rf-SQUIDs is considered. We show that the scattering changes for large amplitudes of the incident electromagnetic wave; above a critical amplitude, two different refraction states occur (bistability). In particular, for these two states, the transmitted wave polarization and angle of refraction are different. One could then switch the direction of propagation of the electromagnetic wave and its polarization with a "thin film", whose thickness is much smaller than the wavelength.
Long Pulse Fusion Physics Experiments without Superconducting Electromagnets
Woolley, R.D.
1998-08-19
Long-pulse fusion physics experiments can be performed economically via resistive electromagnets designed for thermally steady-state operation. Possible fusion experiments using resistive electromagnets include long-pulse ignition with deuterium-tritium fuel. Long-pulse resistive electromagnets are alternatives to today's delicate and costly superconductors. At any rate, superconducting technology is now evolving independent of fusion, so near-term superconducting experience may not ultimately be useful.
Relativistic electromagnetic mass models in spherically symmetric spacetime
S. K. Maurya; Y. K. Gupta; Saibal Ray; Vikram Chatterjee
2015-07-04
Under the static spherically symmetric Einstein-Maxwell spacetime of embedding class one we explore possibility of electromagnetic mass model where mass and other physical parameters have purely electromagnetic origin (Tiwari 1984, Gautreau 1985, Gron 1985). This work is in continuation of our earlier investigation (Maurya 2015a) where we developed an algorithm and found out three new solutions of electromagnetic mass models. In the present letter we consider different metric potentials $\
An electromagnetic theory of turbulence driven poloidal rotation
McDevitt, C. J.; Guercan, Oe. D.
2012-10-15
An electromagnetic theory of turbulence driven poloidal rotation is developed with particular emphasis on understanding poloidal rotation in finite-{beta} plasmas. A relation linking the flux of polarization charge to the divergence of the total turbulent stress is derived for electromagnetic gyrokinetic modes. This relation is subsequently utilized to derive a constraint on the net electromagnetic turbulent stress exerted on the poloidal flow. Various limiting cases of this constraint are considered, where it is found that electromagnetic contributions to the turbulent stress may either enhance or reduce the net turbulent stress depending upon the branch of turbulence excited.
Novel resonance-assisted electromagnetic-transport phenomena
Kurs, André B
2011-01-01
We first demonstrate theoretically and experimentally that electromagnetic resonators with high quality factors (Q) can be used to transfer power efficiently over distances substantially larger than the characteristic ...
Motion of charged particles in an electromagnetic knot
M. Arrayás; J. L. Trueba
2010-01-27
In this paper we consider the classical relativistic motion of charged particles in a knotted electromagnetic field. After reviewing how to construct electromagnetic knots from maps between the three-sphere and the two-sphere, we introduce a mean quadratic radius of the energy density distribution in order to study some properties of this field. We study the classical relativistic motion of electrons in the electromagnetic field of the Hopf map, and compute their trajectories. It is observed that these electrons initially at rest are strongly accelerated by the electromagnetic force, becoming ultrarelativistic in a period of time that depends on the knot energy and size.
Electromagnetic scattering and induction models for spheroidal geometries
Barrowes, Benjamin E., 1973-
2004-01-01
Electromagnetic scattering from a medium containing randomly distributed discrete dielectric spheroidal inclusions is studied. Also, the broadband magnetoquasistatic solution for the induced magnetic field from a conducting ...
6.013 Electromagnetics and Applications, Fall 2002
Staelin, David H.
Electromagnetic phenomena are explored in modern applications including wireless communications, circuits, computer interconnects and peripherals, optical fiber links and components, microwave communications and radar, ...
Thermodynamic restrictions on the constitutive equations of electromagnetic theory
NASA Technical Reports Server (NTRS)
Coleman, B. D.; Dill, E. H.
1971-01-01
Thermodynamics second law restrictions on constitutive equations of electromagnetic theory for nonlinear materials with long-range gradually fading memory, considering dissipation principle consequences
Assessing the benefits of DCT compressive sensing for computational electromagnetics
D'Ambrosio, Kristie (Kristie L.)
2011-01-01
Computational electromagnetic problems are becoming exceedingly complex and traditional computation methods are simply no longer good enough for our technologically advancing world. Compressive sensing theory states that ...
6.641 Electromagnetic Fields, Forces, and Motion, Spring 2003
Zahn, Markus, 1946-
Electric and magnetic quasistatic forms of Maxwell's equations applied to dielectric, conduction, and magnetization boundary value problems. Electromagnetic forces, force densities, and stress tensors, including magnetization ...