NSDL National Science Digital Library
2012-08-03
This is an activity about the properties of electromagnets, which is a crucial underpinning for understanding how magnetic fields are generated in nature, in the surface of the Sun, and in the interior of Earth. Learners will create an electromagnet by letting an electric current flow through a wire to generate a magnetic field, which is then detected using a compass. This activity requires a thin insulated wire, pencil, battery, compass and paper clips. This is Activity 2 of the Magnetism and Electromagnetism teachers guide.
NSDL National Science Digital Library
Michael Horton
2009-05-30
In this investigation, students will construct electromagnets and test to see which variables make them stronger. Although elementary and middle school teachers are expected to have done this activity with their classes, teachers of younger students often
NSDL National Science Digital Library
VU Bioengineering RET Program,
In this activity, the students will complete the grand challenge and design an electromagnet to separate steel from aluminum for the recycler. In order to do this, students compare the induced magnetic field of an electric current with the magnetic field of a permanent magnet and must make the former look like the latter. They discover that looping the current produces the desired effect and find ways to further strengthen the magnetic field.
ERIC Educational Resources Information Center
Milson, James L.
1990-01-01
Three activities involving electromagnetism are presented. Discussed are investigations involving the construction of an electromagnet, the effect of the number of turns of wire in the magnet, and the effect of the number of batteries in the circuit. Extension activities are suggested. (CW)
NSDL National Science Digital Library
The University of California Regents
2014-01-01
This is an interactive online activity, in which learners equip a virtual electromagnet and see how many iron filings it can pick up. Learners change various characteristics of the electromagnet including the number of windings, the gage of the wire, the current type (AC or DC), the material used in the wire, and the voltage on the power supply.
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.
NASA Astrophysics Data System (ADS)
Land, Jared
2012-03-01
The objective of this senior physics student research project was to design a functional electromagnetic accelerator (i.e. railgun), with considerations for size, portability, modularity, and weight. This has been accomplished through practical design application of electromagnetic principles and streamlined construction to study effects of various rail geometries/bore profiles, and projectile design. The railgun has been tested and its efficiency has been studied.
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.
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...
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....
Electromagnetic microactuators
NASA Astrophysics Data System (ADS)
Büttgenbach, S.; Al-Halhouli, A. T.; Feldmann, M.; Seidemann, V.; Waldschik, A.
2013-05-01
High precision microactuators have become key elements for many applications of MEMS, for example for positioning and handling systems as well as for microfluidic devices. Electromagnetic microactuators exhibit considerable benefits such as high forces, large deflections, low input impedances and thus, the involvement of only low voltages. Most of the magnetic microactuators developed so far are based on the variable reluctance principle and use soft magnetic materials. Since the driving force of such actuators is proportional to their volume, they require structures with rather great heights and aspect ratios. Therefore, the development of new photo resists, which allow UV exposure of thick layers of resist, has been essential for the advancement of variable reluctance microactuators. On the other hand, hard magnetic materials have the potential for larger forces and larger deflections. Accordingly, polymer magnets, in which micro particles of hard magnetic material are suspended in a polymer matrix, have been used to fabricate permanent magnet microactuators. In this paper we give an overview of sophisticated electromagnetic microactuators which have been developed in our laboratory in the framework of the Collaborative Research Center "Design and Manufacturing of Active Microsystems". In particular, concept, fabrication and test of variable reluctance micro stepper motors, of permanent magnet synchronous micromotors and of microactuators based on the Lorentz force principle will be described. Special emphasis will be given to applications in lab-on-chip systems.
NSDL National Science Digital Library
2014-09-18
Student teams investigate the properties of electromagnets. They create their own small electromagnet and experiment with ways to change its strength to pick up more paper clips. Students learn about ways that engineers use electromagnets in everyday applications.
Gravito-electromagnetism versus electromagnetism
Angelo Tartaglia; Matteo Luca Ruggiero
2003-11-07
The paper contains a discussion of the properties of the gravito-magnetic interaction in non stationary conditions. A direct deduction of the equivalent of Faraday-Henry law is given. A comparison is made between the gravito-magnetic and the electro-magnetic induction, and it is shown that there is no Meissner-like effect for superfluids in the field of massive spinning bodies. The impossibility of stationary motions in directions not along the lines of the gravito-magnetic field is found. Finally the results are discussed in relation with the behavior of superconductors.
Gravito-electromagnetism versus electromagnetism
Tartaglia, A; Tartaglia, Angelo; Ruggiero, Matteo Luca
2004-01-01
The paper contains a discussion of the properties of the gravito-magnetic interaction in non stationary conditions. A direct deduction of the equivalent of Faraday-Henry law is given. A comparison is made between the gravito-magnetic and the electro-magnetic induction, and it is shown that there is no Meissner-like effect for superfluids in the field of massive spinning bodies. The impossibility of stationary motions in directions not along the lines of the gravito-magnetic field is found. Finally the results are discussed in relation with the behavior of superconductors.
Electromagnetic topology: Characterization of internal electromagnetic coupling
NASA Technical Reports Server (NTRS)
Parmantier, J. P.; Aparicio, J. P.; Faure, F.
1991-01-01
The main principles are presented of a method dealing with the resolution of electromagnetic internal problems: Electromagnetic Topology. A very interesting way is to generalize the multiconductor transmission line network theory to the basic equation of the Electromagnetic Topology: the BLT equation. This generalization is illustrated by the treatment of an aperture as a four port junction. Analytical and experimental derivations of the scattering parameters are presented. These concepts are used to study the electromagnetic coupling in a scale model of an aircraft, and can be seen as a convenient means to test internal electromagnetic interference.
Laskaris, E.T.; Chari, M.V.K.
1990-11-20
This paper describes an electromagnetic launcher. It comprises: a stationary superconductive coil situated coaxially in a cylindrical vacuum vessel for providing a magnetic field. The superconductive coil having a central aperture, the vacuum vessel having an axially extending bore passing through the central aperture of the superconducting coil; a resistive coil situated coaxially with the superconductive coil and movable axially relative to the stationary superconductive coil, the outer diameter of the resistive coil being smaller than the inner diameter of the bore permitting the resistive coil to pass therethrough; launch activating means coupled to the resistive coil. The launch activating means comprising a shaft joined at one end to the resistive coil, a tube open at both ends, a sliding piston situated in the tube and connected to the other end of the shaft; and power supply means coupled to the resistive coil for providing current of a desired direction and magnitude, so that energization of the resistive coil in the presence of the radial field component of the magnetic field of the superconductive coil creates an axial force on the movable coil, the direction and magnitude of which is dependent on the direction and magnitude of the current in the resistive coil.
Investigation of electromagnetic welding
Pressl, Daniel G. (Daniel Gerd)
2009-01-01
We propose several methodologies to study and optimize the electromagnetic process for Electromagnetic Forming (EMF) and Welding (EMW), thereby lowering the necessary process energy up to a factor of three and lengthening ...
Electromagnetic Interference (Emi)
Mike Hardage; Philip D. Henry
\\u000a Electric and magnetic signals originating outside of a defibrillator may affect its operation, a phenomenon known as electromagnetic\\u000a interference (EMI). EMI usually refers to interference from environmental electromagnetic instrumentation and should be distinguished\\u000a from other sources of electromagnetic noise causing ICD malfunction (Table 1). Signals most likely to penetrate and affect\\u000a pacemakers and ICDs are electromagnetic waves or signals at
Electromagnetic 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
The electromagnetic spike solutions
NASA Astrophysics Data System (ADS)
Nungesser, Ernesto; Lim, Woei Chet
2013-12-01
The aim of this paper is to use the existing relation between polarized electromagnetic Gowdy spacetimes and vacuum Gowdy spacetimes to find explicit solutions for electromagnetic spikes by a procedure which has been developed by one of the authors for gravitational spikes. We present new inhomogeneous solutions which we call the EME and MEM electromagnetic spike solutions.
Electromagnetic Radiation: On Trial
NSDL National Science Digital Library
This activity introduces students to the properties of electromagnetic radiation in a variety of ways. For example, they put the different types of the electromagnetic radiation on trial, selecting the judge, prosecutor, defense counsel, and jury, and learning about electromagnetic energy by arguing the pros and cons of each wavelength. During this activity, students are introduced to the general properties of electromagnetic waves, learn to analyze the relation between the specific properties of waves and their position in the electromagnetic spectrum, and discuss methods used to detect and analyze different waves. Students also learn about scientists whose work contributed to our understanding of electromagnetic energy. Students are encouraged to use an electronic bulletin board to communicate with each other, posting insights, ideas, evidence and questions on electromagnetic energy.
8.07 Electromagnetism II, Fall 2002
Zwiebach, Barton
Survey of basic electromagnetic phenomena: electrostatics, magnetostatics; electromagnetic properties of matter. Time-dependent electromagnetic fields and Maxwell's equations. Electromagnetic waves, emission, absorption, ...
NSDL National Science Digital Library
VU Bioengineering RET Program,
Students design and construct an electromagnet that must pick up 10 staples. They begin with only minimal guidance, and after the basic concept is understood, are informed of the properties that affect the strength of that magnet. They conclude by designing their own electromagnet to complete the challenge of separating scrap steel from scrap aluminum for recycling and share it with the class.
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…
Electromagnetic field versus EXCEL
NASA Astrophysics Data System (ADS)
Henzl, Ctibor
2004-04-01
Spreadsheet EXCEL is known as the software commonly oriented on statistic or economics. Its application in the electromagnetic field theory is rather rare. But many of the features of EXCEL are applicable in the calculations in electromagnetism. Some of them are described in this paper. Implementation of basic numerical methods into EXCEL is given here as well.
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.
"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…
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.
Wave propagation in electromagnetic media
1990-01-01
This book is concerned with wave propagation in reacting media, specifically in electromagnetic materials. An account is presented of the mathematical methods of wave phenomena in electromagnetic materials. The author presents the theory of time-varying electromagnetic fields, which involves a discussion of Faraday's laws, Maxwell's equations and their application to electromagnetic wave propagation under a variety of conditions. The author
Electromagnetism in the Movies.
ERIC Educational Resources Information Center
Everitt, Lori R.; Patterson, Evelyn T.
1999-01-01
Describes how the authors used portions of popular movies to help students review concepts related to electromagnetism. Movies used and concepts covered in the review are listed, and a sample activity is described. (WRM)
Microslots : scalable electromagnetic instrumentation
Maguire, Yael G., 1975-
2004-01-01
This thesis explores spin manipulation, fabrication techniques and boundary conditions of electromagnetism to bridge the macroscopic and microscopic worlds of biology, chemistry and electronics. This work is centered around ...
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.
Rodriguez, Jose
2008-01-01
This work is an introduction to modern mathematical physics. We begin with Maxwell laws and vector calculus, pass next to consider the action and the Feynman integral in quantum mechanics, next relativity and differential geometry to formulate the electromagnetic laws in intrinsic form. Next we see gravitation to study the covariant derivative. We end with the electromagnetic bundle U(1). It contains the know-how + the know-why. The text is written in Spanish. 340 pps.
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.
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.
Introducing electromagnetic field momentum
NASA Astrophysics Data System (ADS)
Yu-Kuang Hu, Ben
2012-07-01
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 analysis and without using vector calculus identities or the need to evaluate integrals. I use this result to show that linear and angular momenta are conserved for a charge in the presence of a magnetic dipole when the dipole strength is changed.
Improved Electromagnetic Brake
NASA Technical Reports Server (NTRS)
Martin, Toby B.
2004-01-01
A proposed design for an electromagnetic brake would increase the reliability while reducing the number of parts and the weight, relative to a prior commercially available electromagnetic brake. The reductions of weight and the number of parts could also lead to a reduction of cost. A description of the commercial brake is prerequisite to a description of the proposed electromagnetic brake. The commercial brake (see upper part of figure) includes (1) a permanent magnet and an electromagnet coil on a stator and (2) a rotor that includes a steel contact plate mounted, with tension spring loading, on an aluminum hub. The stator is mounted securely on a stationary object, which would ordinarily be the housing of a gear drive or a motor. The rotor is mounted on the shaft of the gear drive or motor. The commercial brake nominally operates in a fail-safe (in the sense of normally braking) mode: In the absence of current in the electromagnet coil, the permanent magnet pulls the contact plate, against the spring tension, into contact with the stator. To release the brake, one excites the electromagnet with a current of the magnitude and polarity chosen to cancel the magnetic flux of the permanent magnet, thereby enabling the spring tension to pull the contact plate out of contact with the stator. The fail-safe operation of the commercial brake depends on careful mounting of the rotor in relation to the stator. The rotor/stator gap must be set with a tolerance between 10 and 15 mils (between about 0.25 and about 0.38 mm). If the gap or the contact pad is thicker than the maximum allowable value, then the permanent magnetic field will not be strong enough to pull the steel plate across the gap. (For this reason, any contact pad between the contact plate and the stator must also be correspondingly thin.) If the gap exceeds the maximum allowable value because of shaft end play, it becomes impossible to set the brake by turning off the electromagnet current. Although it may still be possible to set the brake by applying an electromagnet current to aid the permanent magnetic field instead of canceling it, this action can mask an out-of-tolerance condition in the brake and it does not restore the fail-safe function of setting the brake when current is lost.
Electromagnetic 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.
NASA Astrophysics Data System (ADS)
Ponds, C. D.
1985-01-01
This report presents the design and test requirements in developing an electromagnetic compatibility missile system. Environmental levels are presented for electromagnetic radiation hazards, electromagnetic radiation operational electrostatic discharge, lightning, and electromagnetic pulse (nuclear). Testing techniques and facility capabilities are presented for research and development testing of missile systems.
Spectroscopy Interaction of electromagnetic radiation
Gerwert, Klaus
Spectroscopy 691 Interaction of electromagnetic radiation with atoms or molecules #12;Spectroscopy 691 Interaction of electromagnetic radiation with atoms or molecules two processes: emission ähnliche chemische Eigenschaften. #12;Intensity 695 #12;Spectroscopy 22 Quantum-mechanics Classic 2-atomic
Search for Neutrino Electromagnetic Interaction
Rashba, Timur
2006-01-06
In the talk we discuss neutrino electromagnetic properties. The theoretical grounds, direct experimental searches and possible astrophysical applications (Early universe, Supernovae and the Sun) of neutrino electromagnetic moments are briefly reviewed.
Electromagnetically Induced Flows Michiel de Reus
Vuik, Kees
Electromagnetically Induced Flows in Water Michiel de Reus 8 maart 2013 () Electromagnetically Conclusion and future research () Electromagnetically Induced Flows 2 / 56 #12;1 Introduction 2 Maxwell Navier Stokes equations 5 Simulations 6 Conclusion and future research () Electromagnetically Induced
8.07 Electromagnetism II, Fall 2005
Bertschinger, Edmund
This course is the second in a series on Electromagnetism beginning with Electromagnetism I (8.02 or 8.022). It is a survey of basic electromagnetic phenomena: electrostatics; magnetostatics; electromagnetic properties of ...
Superconductivity for electromagnetic guns
O. K. Mawardi
1984-01-01
This report deals with a feasibility study for an electromagnetic gun using superconducting components. The report discusses two questions. The first deals with an assessment of the applied superconductivity technology, while the second is concerned with two reference designs for coaxial accelerators making use of advanced energy transfer concepts. Impressive recent developments in the technology of cryogenic insulation and of
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.
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.
What are Electromagnetic Metamaterials?
NSDL National Science Digital Library
Metamaterials are artificial structures that display properties beyond those available in naturally occuring materials. Materials interact with light and other electromagnetic fields. Because of this, materials can be used to control light in various ways, forming the basis for optical devices. This website from Duke University gives more details and graphs.
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
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 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
Pastore, Saori
2015-01-01
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.
Department of Electroscience Electromagnetic Theory
Cheney, Margaret
Department of Electroscience Electromagnetic Theory Lund Institute of Technology Sweden CODEN:LUTEDX/(TEAT-7091)/1-24/(2000) Optimal Electromagnetic Measurements Margaret Cheney and Gerhard Kristensson #12@rpi.edu Gerhard Kristensson Department of Electroscience Electromagnetic Theory Lund Institute of Technology P
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. [and others
1996-10-01
This is the final report of a one-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). Electromagnetic pulse (EMP) signals produced from explosives being fired have been reported in the literature for fifty years. When a gun is fired it produces an EMP muzzle blast signal. The strength and nature of these signals was first analyzed in the early 1970s, while the results were interesting, no follow-up studies were conducted. With modern detection and signal processing technology, we believe that these signals could be used to instantaneously locate guns of virtually all calibers as they fire. The objective of our one-year project was to establish the basic nature of these signals and their utility in the concept of electromagnetic targeting of guns.
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.
Electromagnetic Polarizabilities of Mesons
A. Aleksejevs; S. Barkanova
2014-11-16
The Chiral Perturbation Theory (CHPT) has been very successful in describing low-energy hadronic properties in the non-perturbative regime of Quantum Chromodynamics. The results of ChPT, many of which are currently under active experimental investigation, provide stringent predictions of many fundamental properties of hadrons, including quantities such as electromagnetic polarizabilities. Yet, even for the simplest hadronic system, a pion, we still have a broad spectrum of polarizability measurements (MARK II, VENUS, ALEPH, TPC/2g, CELLO, Belle, Crystal Ball). The meson polarizability can be accessed through Compton scattering, so we can measure it through Primakoff reaction. This paper will provide an analysis of the CHPT predictions of the SU(3) meson electromagnetic polarizabilities and outline their relationship to the Primakoff cross section at the kinematics relevant to the planned JLab experiments.
Electromagnetic Wave Source Conditions
Oskooi, Ardavan
2013-01-01
This chapter discusses the relationships between current sources and the resulting electromagnetic waves in FDTD simulations. First, the "total-field/scattered-field" approach to creating incident plane waves is reviewed and seen to be a special case of the well-known principle of equivalence in electromagnetism: this can be used to construct "equivalent" current sources for any desired incident field, including waveguide modes. The effects of dispersion and discretization are discussed, and a simple technique to separate incident and scattered fields is described in order to compensate for imperfect equivalent currents. The important concept of the local density of states (LDOS) is reviewed, which elucidates the relationship between current sources and the resulting fields, including enhancement of the LDOS via mode cutoffs (Van Hove singularities) and resonant cavities (Purcell enhancement). We also address various other source techniques such as covering a wide range of frequencies and incident angles in a...
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.
Electromagnetic Stepping Drives
Christian Richter; Thomas Roschke
In Chapter 3 electromagnetic stepping drives are introduced. Stepping motors started into widespread use with the advent of\\u000a digital computers end of the 1970's and their use in computer peripherals. Their stepwise digital control by pattern is well\\u000a adapted to the digital world. An overview about the most important types of stepping motors, such as tin-can, disk rotor,\\u000a reluctance and
Electromagnetic tornadoes in space
Chang, T.; Crew, G.B.; Retterer, J.M.
1988-01-01
The exotic phenomenon of energetic-ion conic formation by plasma waves in the magnetosphere is considered. Two particular transverse heating mechanisms are reviewed in detail; lower-hybrid energization of ions in the boundary layer of the plasma sheet and electromagnetic ion cyclotron resonance heating in the central region of the plasma sheet. Mean particle calculations, plasma simulations and analytical treatments of the heating processes are described.
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.
Entanglement of electromagnetic fields
Enk, S.J. van
2003-02-01
Given a quantum state of the electromagnetic field, one is, in principle, free to redefine the field modes. We show here how the amount of entanglement in a given state depends on redefinitions of the modes, and calculate the minimum and maximum entanglement over all such redefinitions for several examples. Redefinitions can also be interpreted as transformations that one can apply actively, for example, in order to create nonlocal entanglement.
Electromagnetic polarizabilities of hadrons
Friar, J.L.
1988-01-01
Electromagnetic polarizabilities of hadrons are reviewed, after a discussion of classical analogues. Differences between relativistic and non-relativistic approaches can lead to conflicts with conventional nuclear physics sum rules and calculational techniques. The nucleon polarizabilities are discussed in the context of the non-relativistic valence quark model, which provides a good qualitative description. The recently measured pion polarizabilities are discussed in the context of chiral symmetry and quark-loop models. 58 refs., 5 figs.
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.
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.
Electromagnetic Hammer for Metalworking
NASA Technical Reports Server (NTRS)
Anderson, S. A.; Brunet, F.; Dowd, A.; Durham, R.; Ezell, J.; Gorr, G.; Hartley, D.; Jackson, F.; Marchand, J.; Macfarlane, W.; Nameth, P.; Okelly, K.; Phillips, H.; Rollo, J.; Rupert, E.; Sykes, H.; Vitrano, E.; Woods, M.
1986-01-01
High eddy currents apply pressure for cold-forming. Coil housing constructed for mechanical strength to hold coil against magnetic force, to maintain electrical contact with coil ends, and to maintain insulation between coil turns. Drilled holes placed to facilitate release of bubbles during potting. In contrast with mechanical hammers, electromagnetic hammer requires no dynamic material contact with workpiece; consequently, produces almost no change in metal grain structure.
Manuel Arrayás; José L. Trueba
2012-03-26
We present a new range of solutions of the Maxwell equations in vacuum in which the topology of the field lines is that of the whole torus knots set. Knotted electromagnetic fields are solutions of the Maxwell equations in vacuum in which magnetic lines, and also electric lines, have some kind of linkage. These solutions may play an important role in fundamental physics problems from the stability of field configurations, such as plasma confinement, to coding information.
Electromagnetic fields in offices.
Sandström, Monica
2006-01-01
With the increased use of electric and electronic equipment in our offices, our daily exposure to electromagnetic fields has become increasingly complex due to the great variety of the frequency content of the fields. Today focus has shifted from monitors as the dominating sources of electromagnetic fields to other electronic equipment, cabling, nearby substations, power lines and stray currents in buildings. In the last 5 years wireless communication has become common in our offices. These devices use radio frequency waves to communicate and are therefore sources of radio frequency fields in our offices. To a certain degree, they all add to the complicated issue of the extensive field frequencies found in offices. The exposure of office workers is generally considered to be low and not in conflict with the existing guidelines, but if a precaution approach is applied there are a number of measures that can be taken to reduce the electromagnetic fields in offices in order to obtain a good electrical environment. PMID:16790171
Gravito-electromagnetic analogies
L. Filipe O. Costa; José Natário
2014-10-25
We reexamine and further develop different gravito-electromagnetic (GEM) analogies found in the literature, and clarify the connection between them. Special emphasis is placed in two exact physical analogies: the analogy based on inertial fields from the so-called "1+3 formalism", and the analogy based on tidal tensors. Both are reformulated, extended and generalized. We write in both formalisms the Maxwell and the full exact Einstein field equations with sources, plus the algebraic Bianchi identities, which are cast as the source-free equations for the gravitational field. New results within each approach are unveiled. The well known analogy between linearized gravity and electromagnetism in Lorentz frames is obtained as a limiting case of the exact ones. The formal analogies between the Maxwell and Weyl tensors are also discussed, and, together with insight from the other approaches, used to physically interpret gravitational radiation. The precise conditions under which a similarity between gravity and electromagnetism occurs are discussed, and we conclude by summarizing the main outcome of each approach.
Nuclear Electromagnetic Pulse Review
NASA Astrophysics Data System (ADS)
Dinallo, Michael
2011-04-01
Electromagnetic Pulse (EMP) from nuclear detonations have been observed for well over half a century. Beginning in the mid-to-late 1950s, the physics and modeling of EMP has been researched and will continue into the foreseeable future. The EMP environment propagates hundreds of miles from its origins and causes interference for all types of electronic instrumentation. This includes military, municipal and industry based electronic infrastructures such as power generation and distribution, command and control systems, systems used in financial and emergency services, electronic monitoring and communications networks, to mention some key infrastructure elements. Research into EMP has included originating physics, propagation and electromagnetic field coupling analyses and measurement-sensor development. Several methods for calculating EMP induced transient interference (voltage and current induction) will be briefly discussed and protection techniques reviewed. These methods can be mathematically simple or involve challenging boundary value solution techniques. A few illustrative calculations will demonstrate the concern for electronic system operability. Analyses such as the Wunsch-Bell model for electronic upset or damage, and the Singularity Expansion Method (SEM) put forth by Dr. Carl Baum, will facilitate the concern for EMP effects. The SEM determines the voltages and currents induced from transient electromagnetic fields in terms of natural modes of various types of electronic platforms (aerospace vehicles or land-based assets - fixed or mobile). Full-scale facility and laboratory simulation and response measurement approaches will be discussed. The talk will conclude with a discussion of some present research activities.
Gravito-electromagnetic analogies
NASA Astrophysics Data System (ADS)
Costa, L. Filipe O.; Natário, José
2014-10-01
We reexamine and further develop different gravito-electromagnetic (GEM) analogies found in the literature, and clarify the connection between them. Special emphasis is placed in two exact physical analogies: the analogy based on inertial fields from the so-called "1+3 formalism", and the analogy based on tidal tensors. Both are reformulated, extended and generalized. We write in both formalisms the Maxwell and the full exact Einstein field equations with sources, plus the algebraic Bianchi identities, which are cast as the source-free equations for the gravitational field. New results within each approach are unveiled. The well known analogy between linearized gravity and electromagnetism in Lorentz frames is obtained as a limiting case of the exact ones. The formal analogies between the Maxwell and Weyl tensors are also discussed, and, together with insight from the other approaches, used to physically interpret gravitational radiation. The precise conditions under which a similarity between gravity and electromagnetism occurs are discussed, and we conclude by summarizing the main outcome of each approach.
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.
Electromagnetic field and cosmic censorship
Koray Düzta?
2014-04-09
We construct a gedanken experiment in which an extremal Kerr black hole interacts with a test electromagnetic field. Using Teukolsky's solutions for electromagnetic perturbations in Kerr spacetime, and the conservation laws imposed by the energy momentum tensor of the electromagnetic field and the Killing vectors of the spacetime, we prove that this interaction cannot convert the black hole into a naked singularity, thus cosmic censorship conjecture is not violated in this case.
Electromagnetic field and cosmic censorship
Düzta?, Koray
2013-01-01
We construct a gedanken experiment in which an extremal Kerr black hole interacts with a test electromagnetic field. Using Teukolsky's solutions for electromagnetic perturbations in Kerr spacetime, and the conservation laws imposed by the energy momentum tensor of the electromagnetic field and the Killing vectors of the spacetime, we prove that this interaction cannot convert the black hole into a naked singularity, thus cosmic censorship conjecture is not violated in this case.
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.
The ALICE Electromagnetic Calorimeter
Awes, Terry C; ALICE, Collaboration
2010-01-01
ALICE is the general purpose experiment at the LHC dedicated to the study of heavy-ion collisions. The electromagnetic calorimeter (EMCal) is a late addition to the ALICE suite of detectors with first modules installed in ALICE this year. The EMCal is designed to trigger on high energy gamma-rays and jets, and to enhance the capabilities of ALICE for these measurements. The EMCal is a Pb/scintillator sampling shish-kebab type calorimeter. The EMCal construction, readout, and performance in beam tests at the CERN SPS and PS are described.
The ALICE Electromagnetic Calorimeter
Awes, Terry C; ALICE, Collaboration
2010-05-01
ALICE is the general purpose experiment at the LHC dedicated to the study of heavy-ion collisions. The electromagnetic calorimeter (EMCal) is a late addition to the ALICE suite of detectors with first modules installed in ALICE this year. The EMCal is designed to trigger on high energy gamma-rays and jets, and to enhance the capabilities of ALICE for these measurements. The EMCal is a Pb/scintillator sampling shish-kebab type calorimeter. The EMCal construction, readout, and performance in beam tests at the CERN SPS and PS are described.
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
2015-07-21
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.
Electromagnetics and Applications
NSDL National Science Digital Library
This course, presented by MIT, explores electromagnetic phenomena in modern applications. Some of these include: wireless communications, circuits, computer interconnects and peripherals, optical fiber links and components, microwave communications and radar, antennas, sensors, micro-electromechanical systems, motors, and power generation and transmission. Fundamentals covered include: quasistatic and dynamic solutions to Maxwell's equations; waves, radiation, and diffraction; coupling to media and structures; guided and unguided waves; resonance; and forces, power, and energy. Additionally, the site contains lecture notes, assignments and an online textbook featuring videos.
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.
Interactive electromagnetic launcher simulation
NASA Astrophysics Data System (ADS)
Young, F. J.; Howland, H. R.; Hughes, W. F.; Fikse, D. A.
1982-01-01
The mathematical model, usage, and documentation of an interactive computer simulation for an electromagnetic launcher is presented. The launcher is modeled as an electrical circuit. Three slight variations of the program permit studies of a launcher with (1) rail skin effects, (2) rail skin effects and approximated storage coil skin effects, or (3) neither of these effects. Usage of the program as currently implemented on the Westinghouse R&D Univac 1106 is described, with a sample session shown. The implementation of the program permits rapid scoping of the effects of parameter changes.
Electromagnetic pump stator coil
Fanning, Alan W. (San Jose, CA); Dahl, Leslie R. (Livermore, CA)
1996-01-01
An electrical stator coil for an electromagnetic pump includes a continuous conductor strip having first and second terminals at opposite ends thereof and an intermediate section disposed therebetween. The strip is configured in first and second coil halves, with the first coil half including a plurality of windings extending from the first terminal to the intermediate section, and the second coil half including a plurality of windings extending from the second terminal to the intermediate section. The first and second coil halves are disposed coaxially, and the first and second terminals are disposed radially inwardly therefrom with the intermediate section being disposed radially outwardly therefrom.
Electromagnetic pump stator coil
Fanning, A.W.; Dahl, L.R.
1996-06-25
An electrical stator coil for an electromagnetic pump includes a continuous conductor strip having first and second terminals at opposite ends thereof and an intermediate section disposed therebetween. The strip is configured in first and second coil halves, with the first coil half including a plurality of windings extending from the first terminal to the intermediate section, and the second coil half including a plurality of windings extending from the second terminal to the intermediate section. The first and second coil halves are disposed coaxially, and the first and second terminals are disposed radially inwardly therefrom with the intermediate section being disposed radially outwardly therefrom. 9 figs.
Unbalanced electromagnetic forces
Hansen, Craig Martin
1974-01-01
(k+1) assuming v?c and 2(6+R) cos8?1 (3. 13) Normalized Force F a cot6 F ~M za cot0 . 0001 . 0002 . 0005 . 001 . 002 . 005 . 01 . 02 . 05 . 1 . 2 . 5 d /R Figure III-2. Semi lcg plot of the normalized average unbalanced magnetic and electric... 10 ) q acotB F 16 v2R6 4 ~2R6 (3. 20) So if cot0 -17 ( 5 x 10 )a (3. 21) then F ? F yavg R (3. 22) Because of the limitations already imporsed on the system, condi- tion (3. 21) may always exist. This means that the unbalanced electromagnetic...
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.
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
Interactions between electromagnetic fields
NASA Astrophysics Data System (ADS)
Schwan, H. P.
1985-02-01
We applied for this grant to support a workshop at Erice, Italy. This workshop has been commonly called Erice School and the main subject of this workshop is the interaction of electromagnetic fields with biological cells and molecules. The grant from ONR enabled us to invite American scientists to participants in this workshop and deliver scientific papers. The duration of the Erice School was ten days. Therefore, we had sufficient time to discuss the problems of electromagnetic radiations. Vigorous discussions took place during official sessions and during private conversations. The participants of this workshop are mostly those who have been active in the research on bioelectromagnetics, but there are some numbers of speakers who discussed the basic electrical and magnetic properties of polyelectrolytes, biological membranes and tissue. The workshop was unique in that there were participants with a variety of training backgrounds. This enabled us to exchange the information between applied scientists and basic scientists. Also, active exchanges of opinions took place between biological scientists and physical scientists.
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
Metamaterials beyond electromagnetism
NASA Astrophysics Data System (ADS)
Kadic, Muamer; Bückmann, Tiemo; Schittny, Robert; Wegener, Martin
2013-12-01
Metamaterials are rationally designed man-made structures composed of functional building blocks that are densely packed into an effective (crystalline) material. While metamaterials are mostly associated with negative refractive indices and invisibility cloaking in electromagnetism or optics, the deceptively simple metamaterial concept also applies to rather different areas such as thermodynamics, classical mechanics (including elastostatics, acoustics, fluid dynamics and elastodynamics), and, in principle, also to quantum mechanics. We review the basic concepts, analogies and differences to electromagnetism, and give an overview on the current state of the art regarding theory and experiment—all from the viewpoint of an experimentalist. This review includes homogeneous metamaterials as well as intentionally inhomogeneous metamaterial architectures designed by coordinate-transformation-based approaches analogous to transformation optics. Examples are laminates, transient thermal cloaks, thermal concentrators and inverters, ‘space-coiling’ metamaterials, anisotropic acoustic metamaterials, acoustic free-space and carpet cloaks, cloaks for gravitational surface waves, auxetic mechanical metamaterials, pentamode metamaterials (‘meta-liquids’), mechanical metamaterials with negative dynamic mass density, negative dynamic bulk modulus, or negative phase velocity, seismic metamaterials, cloaks for flexural waves in thin plates and three-dimensional elastostatic cloaks.
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.
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
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 methods of nondestructive testing
Lord, W.
1985-01-01
This book presents papers on electromagnetic testing. Topics considered include numerical field modeling, flow detection in mine hoists, magnetic leakage flux techniques, the evaluation of oil field tubular goods, magnetization, flux density measurement, eddy current inspection of heat exchanger tubing, the testing of steam generator tubing, and the use of electromagnetic non-destructive defect inspection methods in Europe.
Electromagnetic fields and DNA damage
J. L. Phillips; N. P. Singh; H. Lai
2009-01-01
A major concern of the adverse effects of exposure to non-ionizing electromagnetic field (EMF) is cancer induction. Since the majority of cancers are initiated by damage to a cell's genome, studies have been carried out to investigate the effects of electromagnetic fields on DNA and chromosomal structure. Additionally, DNA damage can lead to changes in cellular functions and cell death.
Fast solution methods in electromagnetics
Weng Cho Chew; Jian-Ming Jin; Cai-Cheng Lu; Eric Michielssen; Jiming M. Song
1997-01-01
Various methods for efficiently solving electromagnetic problems are presented. Electromagnetic scattering problems can be roughly classified into surface and volume problems, while fast methods are either differential or integral equation based. The resultant systems of linear equations are either solved directly or iteratively. A review of various differential equation solvers, their complexities, and memory requirements is given. The issues of
Electromagnetic Scattering by Nonspherical Particles
Electromagnetic Scattering by Nonspherical Particles Michael I. Mishchenko and Larry D. Travis NASA (Springer-Verlag, Berlin, 2003), pp. 77 127_ #12;78 Michael I. Mishchenko and Larry D. Travis scattering electromagnetic field (Jackson 1998): · D = , (1) × E = -B/t, (2) · B = 0, (3) × H = J + D/t, (4) where
covariant formulation of electromagnetic wave
equations . . . . . . . . . . . . . . . 6 2.1.3 Construction of the electromagnetic field strength tensorTowards a covariant formulation of electromagnetic wave polarization by Mikael Olofsson Swedish Institute of Space Physics Uppsala-division Box 537 751 21 Uppsala IRF Scientific Report 273 January 2001
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.
The ALICE Electromagnetic Calorimeter
Gadrat, S.
2010-06-01
ALICE (A Large Ion Collider Experiment) is the only LHC experiment at CERN fully dedicated to the study of the quark and gluon plasma. Driven by the RHIC results on jet quenching, the ALICE collaboration has proposed to extend the capabilities of the ALICE detector for the study of high momentum photons and jets by adding a large acceptance calorimeter. This EMCal (ElectroMagnetic Calorimeter) is designed to provide an unbiased fast high-p{sub T} trigger and to measure the neutral energy of jets and photons up to 200 GeV. Four over ten supermodules of the calorimeter have been installed and commissioned at CERN in 2009 which represents 40% of the full acceptance.
Nanofocusing of electromagnetic radiation
NASA Astrophysics Data System (ADS)
Gramotnev, Dmitri K.; Bozhevolnyi, Sergey I.
2014-01-01
Nanofocusing of electromagnetic radiation, that is, reducing the cross sections of propagating optical modes far beyond the diffraction limit in dielectric media, can be achieved in tapered metal-dielectric waveguides that support surface plasmon-polariton modes. Although the main principles of nanofocusing were formulated over a decade ago, a deep theoretical understanding and conclusive experimental verification were achieved only a few years ago. These advances have spawned a variety of new important technological possibilities for the efficient delivery, control and manipulation of optical radiation on the nanoscale. Here, we present the underlying physical principles of radiation nanofocusing in metallic nanostructures, overview recent progress and major developments, and consider future directions and potential applications of this subfield of nano-optics.
Electromagnetic structure of trinucleons
NASA Astrophysics Data System (ADS)
Marcucci, L. E.; Riska, D. O.; Schiavilla, R.
1998-12-01
The electromagnetic form factors of the trinucleons 3H and 3He are calculated with wave functions obtained with the Argonne v18 two-nucleon and Urbana IX three-nucleon interactions. Full account is taken of the two-body currents required by current conservation with the v18 interaction as well as those associated with N? transition currents and the currents of ? resonance components in the wave functions. Explicit three-nucleon current operators associated with the two-pion exchange three-nucleon interaction arising from irreducible S-wave pion-nucleon scattering are constructed and shown to have very little effect on the calculated magnetic form factors. The calculated magnetic form factor of 3H, and charge form factors of both 3H and 3He are in satisfactory agreement with the experimental data. However, the position of the zero in the magnetic form factor of 3He is slightly underpredicted.
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.
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.
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.
Gravitational mass in electromagnetic field
Zihua Weng
2009-08-09
A fraction of energy is theoretically predicted to be captured from electromagnetic field to form a gravitating mass, when a low-mass charged particle enters the strong field from a region of no electromagnetism. In this paper the mass variation has been calculated for a charged particle on free-fall in the constraint electromagnetic field. It has been shown that there is an evident effect to the variation in mass when the low-mass charged particle is in the strong field.
Adjoint charge in electromagnetic field
Zi-Hua Weng
2009-10-07
Making use of the octonion operator, the electromagnetic field generates an adjoint field theoretically. The source of adjoint field includes the adjoint charge and the adjoint current. The adjoint charge has an impact on the gravitational mass and the mass distribution in the electromagnetic field with its adjoint field, and causes further the predictions to departure slightly from the conservation of mass. The inferences can explain why the adjoint charge will influence the mass distribution in the gravitational field and electromagnetic field of celestial bodies. And then the adjoint charge can be considered as one kind of candidate for the dark matter.
Electromagnetic neutrinos in terrestrial experiments and astrophysics
Giunti, Carlo; Li, Yu-Feng; Lokhov, Alexey V; Studenikin, Alexander I; Zhou, Shun
2015-01-01
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 metamaterials: Simplicity unlocks complexity
NASA Astrophysics Data System (ADS)
Dal Negro, Luca
2014-12-01
By carefully selecting only two elemental 'building block materials' at the nanoscale, it is possible to digitally design composite electromagnetic media with properties vastly different from their individual constituents and suitable for performing complex optical functions.
Electromagnetic 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 Implosion Using a Lens
Carl E. Baum
This paper considers the use of dielectric lenses for concentrating a fast pulse on a target (an electromagnetic implosion). There are similarities to and differences from the prolate-spheroidal-reflector case.
Electromagnetic Dissociation and Space Radiation
Norbury, J W; Maung, Khin Maung; Norbury, John W.
2006-01-01
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.
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 ion beam instabilities
NASA Technical Reports Server (NTRS)
Gary, S. P.; Foosland, D. W.; Smith, C. W.; Lee, M. A.; Goldstein, M. L.
1984-01-01
The linear theory of electromagnetic instabilities driven by an energetic ion beam streaming parallel to a magnetic field in a homogeneous Vlasov plasma is considered. Numerical solutions of the full dispersion equation are presented. At propagation parallel to the magnetic field, there are four distinct instabilities. A sufficiently energetic beam gives rise to two unstable modes with right-hand polarization, one resonant with the beam, the other nonresonant. A beam with sufficiently large T (perpendicular to B)/T (parallel to B) gives rise to the left-hand ion cyclotron anisotropy instability at relatively small beam velocities, and a sufficiently hot beam drives unstable a left-hand beam resonant mode. The parametric dependences of the growth rates for the three high beam velocity instabilities are presented here. In addition, some properties at oblique propagation are examined. It is demonstrated that, as the beam drift velocity is increased, relative maxima in growth rates can arise at harmonics of the ion cyclotron resonance for both right and left elliptically polarized modes.
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.
Polarimetry of electromagnetic materials
NASA Astrophysics Data System (ADS)
Asahi, Toru; Osaka, Tetsuya; Kobayashi, Jinzo
2001-07-01
The goal of the polarimetry of electromagnetic solids is the thorough determinations of not only the linear and circular birefringences (LB an CB) but also the linear and circular dichroisms (LD and CD). Needless to say, measurements of circular phenomena are exceedingly more difficult than those of linear ones. For instance, the long period of 170 years elapsed from the discovery of CB by Arago in 1811 until the development of high accuracy universal polarimeter (HAUP) by Kobayashi in 1983, when the first perfect measurements of CB of solids became possible. Subsequent to the appearance of the HAUP method, attempts of extending HAUP theory to be applicable to CD measurements were followed by Moxon and Renshaw, and Dijkstra, Kremers, and Meekes by using Jones matrix calculus. However, their measurements to NiSO4 multiplied by 6H2O were not fully satisfactory. We completed afresh the theory of the extended HAUP and measured successfully LD of a high temperature superconductor Bi2Sr2CaCu2O8. An important fact was clarified; the extended HAUP theory indicates that CD can be obtained exclusively through accurate measurements of (theta) 0, a characteristic angle introduced in the original HAUP method. It means that there would be no ways for measuring CD of solids except for the HAUP method. Preliminary results of applying our theory to silver thiogallate are shown finally.
Electromagnetism on Anisotropic Fractals
Ostoja-Starzewski, Martin
2011-01-01
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 con...
Electromagnetic Interference on Pacemakers
Erdogan, Okan
2002-01-01
External sources, either within or outside the hospital environment, may interfere with the appropriate function of pacemakers which are being implanted all around the world in current medical practice. The patient and the physician who is responsible for follow-up of the pacing systems may be confronted with some specific problems regarding the various types of electromagnetic interference (EMI). To avoid these unwanted EMI effects one must be aware of this potential problem and need to take some precautions. The effects of EMI on pacemaker function and precautions to overcome some specific problems were discussed in this review article. There are many sources of EMI interacting with pacemakers. Magnetic resonance imaging creates real problem and should be avoided in pacemaker patients. Cellular phones might be responsible for EMI when they were held on the same side with the pacemaker. Otherwise they don't cause any specific type of interaction with pacemakers. Sale security systems are not a problem if one walks through it without lingering in or near it. Patients having unipolar pacemaker systems are prone to develop EMI because of pectoral muscle artifacts during vigorous active physical exercise. PMID:17006562
Modern electromagnetic scattering
NASA Astrophysics Data System (ADS)
Yuffa, Alex J.
We develop a numerically stable algorithm for electromagnetic wave propagation through planar stratified media. This algorithm is implemented in a modern programming language and is suitable for the study of such applications as Anderson localization and perfect lensing. Our algorithm remains numerically stable even in the presence of large absorption. Furthermore, in the context of the linear response laws and causality, we analyze a vanishing absorption approximation, which is commonly used in wave scattering problems. We show that it is easy to violate causality in the frequency-domain by making the vanishing absorption approximation. We also develop an orders-of-scattering approximation, termed "screened cylindrical void/core" (SCV) approximation, for wave scattering from a large host cylinder containing N eccentrically embedded core cylinders. The SCV approximation is developed via separation of variables and a cluster T-matrix. We establish the limitations of the SCV approximation and it is in good agreement with the numerically-exact solution. Furthermore, we illustrate that the large host cylinder model with N cylindrical inclusions can be used to theoretically and experimentally investigate strong multiple scattering effects in random media, such as Anderson localization.
Electromagnetic methods in applied geophysics
NASA Astrophysics Data System (ADS)
Vozoff, K.
1980-09-01
Review of promising new research developments dealing with electromagnetic methods in applied geophysics. Slow, steady progress of numerical modeling is seen in traditional low-frequency CW technology. Cryogenic coil systems are viewed as the major development in this area. In the newer area of transient applications, the most impressive results are coming from the use of seismic processing with earth-penetrating radar and the rapid development of transient electromagnetic equipment, theory, and experience.
Electromagnetic Effects in SDF Explosions
H Reichenbach; P Neuwald; A L Kuhl
2010-01-01
The notion of high ion and electron concentrations in the detonation of aluminized explosive mixtures has aroused some interest in electro-magnetic effects that the SDF charges might generate when detonated. Motivated by this interest we have started to investigate whether significant electro-magnetic effects show up in our small-scale experiments. However, the design of instrumentation for this purpose is far from
Canonical quantization of macroscopic electromagnetism
NASA Astrophysics Data System (ADS)
Philbin, T. G.
2010-12-01
Application of the standard canonical quantization rules of quantum field theory to macroscopic electromagnetism has encountered obstacles due to material dispersion and absorption. This has led to a phenomenological approach to macroscopic quantum electrodynamics where no canonical formulation is attempted. In this paper macroscopic electromagnetism is canonically quantized. The results apply to any linear, inhomogeneous, magnetodielectric medium with dielectric functions that obey the Kramers-Kronig relations. The prescriptions of the phenomenological approach are derived from the canonical theory.
Megawatt Electromagnetic Plasma Propulsion
NASA Technical Reports Server (NTRS)
Gilland, James; Lapointe, Michael; Mikellides, Pavlos
2003-01-01
The NASA Glenn Research Center program in megawatt level electric propulsion is centered on electromagnetic acceleration of quasi-neutral plasmas. Specific concepts currently being examined are the Magnetoplasmadynamic (MPD) thruster and the Pulsed Inductive Thruster (PIT). In the case of the MPD thruster, a multifaceted approach of experiments, computational modeling, and systems-level models of self field MPD thrusters is underway. The MPD thruster experimental research consists of a 1-10 MWe, 2 ms pulse-forming-network, a vacuum chamber with two 32 diffusion pumps, and voltage, current, mass flow rate, and thrust stand diagnostics. Current focus is on obtaining repeatable thrust measurements of a Princeton Benchmark type self field thruster operating at 0.5-1 gls of argon. Operation with hydrogen is the ultimate goal to realize the increased efficiency anticipated using the lighter gas. Computational modeling is done using the MACH2 MHD code, which can include real gas effects for propellants of interest to MPD operation. The MACH2 code has been benchmarked against other MPD thruster data, and has been used to create a point design for a 3000 second specific impulse (Isp) MPD thruster. This design is awaiting testing in the experimental facility. For the PIT, a computational investigation using MACH2 has been initiated, with experiments awaiting further funding. Although the calculated results have been found to be sensitive to the initial ionization assumptions, recent results have agreed well with experimental data. Finally, a systems level self-field MPD thruster model has been developed that allows for a mission planner or system designer to input Isp and power level into the model equations and obtain values for efficiency, mass flow rate, and input current and voltage. This model emphasizes algebraic simplicity to allow its incorporation into larger trajectory or system optimization codes. The systems level approach will be extended to the pulsed inductive thruster and other electrodeless thrusters at a future date.
Loyka, Sergey
Statistical Properties of Electromagnetic Environment in Wireless Networks, Intra-Network Electromagnetic Compatibility and Safety Vladimir Mordachev Belorussian State University of Informatics and Radioelectronics (BSUIR) Electromagnetic Compatibility Laboratory 6, P.Brovki st., Minsk 220013, Belarus E
Holographic estimate of electromagnetic mass
NASA Astrophysics Data System (ADS)
Hong, Deog Ki
2015-08-01
Using the gauge/gravity duality, we calculate the electromagnetic contributions to hadron masses, where mass generates dynamically by strong QCD interactions. Based on the Sakai-Sugimoto model of holographic QCD we find that the electromagnetic mass of proton is 0.48 MeV larger than that of neutron, which is in agreement with recent lattice results. Similarly for pions we obtain m ?± - m ? 0 = 1.8 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 KK = 949 MeV.
Un-renormalized Classical Electromagnetism
M. Ibison
2007-04-24
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. Given that, in this respect the direct-action approached ultimately failed because its initial exclusion of self-action was found to be untenable in the relativistic domain, this paper continues the tradition considering 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.
Dipole-induced electromagnetic transparency.
Puthumpally-Joseph, Raiju; Sukharev, Maxim; Atabek, Osman; Charron, Eric
2014-10-17
We determine the optical response of a thin and dense layer of interacting quantum emitters. We show that, in such a dense system, the Lorentz redshift and the associated interaction broadening can be used to control the transmission and reflection spectra. In the presence of overlapping resonances, a dipole-induced electromagnetic transparency (DIET) regime, similar to electromagnetically induced transparency (EIT), may be achieved. DIET relies on destructive interference between the electromagnetic waves emitted by quantum emitters. Carefully tuning material parameters allows us to achieve narrow transmission windows in, otherwise, completely opaque media. We analyze in detail this coherent and collective effect using a generalized Lorentz model and show how it can be controlled. Several potential applications of the phenomenon, such as slow light, are proposed. PMID:25361258
Dipole-Induced Electromagnetic Transparency
NASA Astrophysics Data System (ADS)
Puthumpally-Joseph, Raiju; Sukharev, Maxim; Atabek, Osman; Charron, Eric
2014-10-01
We determine the optical response of a thin and dense layer of interacting quantum emitters. We show that, in such a dense system, the Lorentz redshift and the associated interaction broadening can be used to control the transmission and reflection spectra. In the presence of overlapping resonances, a dipole-induced electromagnetic transparency (DIET) regime, similar to electromagnetically induced transparency (EIT), may be achieved. DIET relies on destructive interference between the electromagnetic waves emitted by quantum emitters. Carefully tuning material parameters allows us to achieve narrow transmission windows in, otherwise, completely opaque media. We analyze in detail this coherent and collective effect using a generalized Lorentz model and show how it can be controlled. Several potential applications of the phenomenon, such as slow light, are proposed.
Dipole-Induced Electromagnetic Transparency
Raiju Puthumpally-Joseph; Maxim Sukharev; Osman Atabek; Eric Charron
2014-09-22
We determine the optical response of a thin and dense layer of interacting quantum emitters. We show that in such a dense system, the Lorentz redshift and the associated interaction broadening can be used to control the transmission and reflection spectra. In the presence of overlapping resonances, a Dipole-Induced Electromagnetic Transparency (DIET) regime, similar to Electromagnetically Induced Transparency (EIT), may be achieved. DIET relies on destructive interference between the electromagnetic waves emitted by quantum emitters. Carefully tuning material parameters allows to achieve narrow transmission windows in otherwise completely opaque media. We analyze in details this coherent and collective effect using a generalized Lorentz model and show how it can be controlled. Several potential applications of the phenomenon, such as slow light, are proposed.
Gauge invariant fractional electromagnetic fields
NASA Astrophysics Data System (ADS)
Lazo, Matheus Jatkoske
2011-09-01
Fractional derivatives and integrations of non-integers orders was introduced more than three centuries ago but only recently gained more attention due to its application on nonlocal phenomenas. In this context, several formulations of fractional electromagnetic fields was proposed, but all these theories suffer from the absence of an effective fractional vector calculus, and in general are non-causal or spatially asymmetric. In order to deal with these difficulties, we propose a spatially symmetric and causal gauge invariant fractional electromagnetic field from a Lagrangian formulation. From our fractional Maxwell's fields arose a definition for the fractional gradient, divergent and curl operators.
Electromagnetic Gun With Commutated Coils
NASA Technical Reports Server (NTRS)
Elliott, David G.
1991-01-01
Proposed electromagnetic gun includes electromagnet coil, turns of which commutated in sequence along barrel. Electrical current fed to two armatures by brushes sliding on bus bars in barrel. Interaction between armature currents and magnetic field from coil produces force accelerating armature, which in turn, pushes on projectile. Commutation scheme chosen so magnetic field approximately coincides and moves with cylindrical region defined by armatures. Scheme has disadvantage of complexity, but in return, enables designer to increase driving magnetic field without increasing armature current. Attainable muzzle velocity increased substantially.
Electromagnetic computations for fusion devices
Turner, L.R.
1989-09-01
Among the difficulties in making nuclear fusion a useful energy source, two important ones are producing the magnetic fields needed to drive and confine the plasma, and controlling the eddy currents induced in electrically conducting components by changing fields. All over the world, researchers are developing electromagnetic codes and employing them to compute electromagnetic effects. Ferromagnetic components of a fusion reactor introduce field distortions. Eddy currents are induced in the vacuum vessel, blanket and other torus components of a tokamak when the plasma current disrupts. These eddy currents lead to large forces, and 3-D codes are being developed to study the currents and forces. 35 refs., 6 figs.
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. PMID:7082396
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.
Quantized electromagnetic tornado in pulsar vacuum gap
Fominov, Yakov
Quantized electromagnetic tornado in pulsar vacuum gap Giant pulses Regular radiation 1937+21 By A of the electromagnetic tornado. The quasi-classical and exact quantization of this rotation is possible. 9 #12;Possible
Electromagnetic formation flight dipole solution planning
Schweighart, Samuel A. (Samuel Adam), 1977-
2005-01-01
Electromagnetic Formation Flight (EMFF) describes the concept of using electromagnets (coupled with reaction wheels) to provide all of the necessary forces and torques needed to maintain a satellite's relative position and ...
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
NASA Astrophysics Data System (ADS)
Bashir, M. F.; Smolyakov, A. I.; Elfimov, A. G.; Melnikov, A. V.; Murtaza, G.
2014-08-01
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 ?e, the safety factor q, and the temperature ratio ? on GAM dispersion are analyzed.
The electromagnetic spectrum : waves of energy
NSDL National Science Digital Library
Tracy Coulson
2002-01-01
In this lesson, students will (1) understand that the sun energy is transferred to Earth by electromagnetic waves, which are transverse waves, (2) understand that there are eight main types of electromagnetic waves, classified on the electromagnetic spectrum according to their wavelengths, and (3) understand how each of the types of electromagnetic radiation is used or found in our everyday lives. This would be a suitable activity for small groups.
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
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 pumping of molten salts
J. Etay; V. Fireteanu; Y. Fautrelle; C. Roman
2010-01-01
This paper investigates the possibility to control through electromagnetic pumping the molten salts flow in high temperature heat transfer applications. Based on finite element models there were evaluated and compared parameters of multi-phase induction pumps with cylindrical, annular or flat pumping channels and of conduction pumps with ac or quasi-dc electric power supply.
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.
Donuts make diffractionless electromagnetic waves
Ya-Lun Tsai; Jyun-Hong Lu; Hua-Kung Chiu; Ching-Yi Chen; Chii-Chang Chen; Jenq-Yang Chang
This work finds that a diffractionless beam can be obtained using periodically arranged donut (torus) waveguides. The Bessel-like field distribution is observed at the output of the waveguide. The structure may be built for electromagnetic waves of any wavelength, including radiowaves, microwaves, infrared light, visible light and UV light. The diameter of the diffractionless beam is of the order of
Electromagnetic Implosion Using an Array
Carl E. Baum; Serhat Altunc; Christos G. Christodoulou; Edl Schamiloglu
2008-01-01
This paper considers the use of a spherical array of sources producing a large fast-transient electromagnetic wave near the center of a sphere. For comparison, a lens type of implosion impulse radiating antenna (IRA) is included as an appendix. This complements the prolate-spheroidal focusing-reflector type of IRA, which has been already appearing in journal papers.
Power electronics and electromagnetic compatibility
R. Redl
1996-01-01
Recently, power electronics has become the dominant factor in the deterioration of the electromagnetic environment, causing declining quality of line power and increasing level of conducted EMI. This paper reviews the fundamentals of EMC in power electronics, including the terminology and categories of EMC, the propagation and generation of low-frequency and high-frequency disturbances, and the various agency regulations. The paper
The courts and electromagnetic fields
Freeman, M. (Univ. of Pennsylvania, Philadelphia (United States))
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 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…
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.
Electromagnetic driving units for complex microrobotic systems
Frank Michel; Wolfgang Ehrfeld; Udo Berg; Reinhard Degen; Felix Schmitz
1998-01-01
Electromagnetic actuators play an important role in macroscopic robotic systems. In combination with motion transformers, like reducing gear units, angular gears or spindle-screw drives, electromagnetic motors in large product lines ensure the rotational or linear motion of robot driving units and grippers while electromagnets drive valves or part conveyors. In this paper micro actuators and miniaturized motion transformers are introduced
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…
2002 by CRC Press LLC Electromagnetic
Nehorai, Arye
and beamforming for electromagnetic (EM) waves are two com- mon objectives of array processing. Early work on DOA© 2002 by CRC Press LLC 17 Electromagnetic Vector Sensors with Beamforming Applications* 17.1 Introduction Advantages of Using Electromagnetic Vector Sensors · Historical Development · Contents
The sensitivity of children to electromagnetic fields
Kheifets, Leeka; Repacholi, M; Saunders, R; van Deventer, E
2005-01-01
Protection. Expo- sure to Static and Low Frequency Electromagnetic Fields:Protection Board. Review of the Scientific Evidence for Limiting Exposure to Electromagnetic Fields (Protection. Guidelines for limiting exposure to time-varying electric, magnetic, and e312 SENSITIVITY OF CHILDREN TO ELECTROMAGNETIC FIELDS
Susceptibility of ICs to Conducted Electromagnetic
This work is focused on the susceptibility of integrated circuits (ICs) to electromagnetic interf erence (EMI). The main issue is simulation and measurement on device level and circuit level. The work gives an overview of th e overall electromagnetic compatibility (EMC) issues, and shows Direct Power Injection (DPI) measurement technique for conducted electromagnetic interference. Related research that is concerned with
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
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
Dynamics and Control of Electromagnetic Satellite Formations
concept that uses superconducting electromagnetic coils to provide forces and torques between differentDynamics and Control of Electromagnetic Satellite Formations Umair Ahsun, David W. Miller June 2007 SSL # 12-07 #12;2 #12;Dynamics and Control of Electromagnetic Satellite Formations by Umair Ahsun B
Localization of Classical Waves II: Electromagnetic Waves.
of electromagnetic waves. This phenomenon arises from coherent multiple scattering and interference, when the scaleLocalization of Classical Waves II: Electromagnetic Waves. Alexander Figotin \\Lambda Department We consider electromagnetic waves in a medium described by a position dependent dielectric constant
Miniaturization of Electromagnetic Bandgap (EBG) Structures with
Swaminathan, Madhavan
packed, electromagnetic interference (EMI) is currently a critical performance issue. To solve this issue/ground pair. since it prevents the propagation of electromagnetic waves within a certain frequency rangeMiniaturization of Electromagnetic Bandgap (EBG) Structures with High-permeability Magnetic Metal
AN ANALYTIC APPROACH TO ELECTROMAGNETIC SCATTERING
electromagnetic field above and below the conducting layer is written as an integral over plane waves. These planeAN ANALYTIC APPROACH TO ELECTROMAGNETIC SCATTERING PROBLEMS Proefschrift ter verkrijging van de from: http://www.library.tudelft.nl/dissertations #12;Summary An analytic approach to electromagnetic
Kilpatrick, M.; Ponds, C.D.
1987-02-01
This report presents the design and test requirements in developing an electromagnetic compatibility missile system. Environmental levels are presented for electromagnetic radiation hazards, electromagnetic radiation operational electrostatic discharge, lightning, and electromagnetic pulse (nuclear). Testing techniques and facility capabilities are presented for research and development testing of missile systems.
Particle Physics in Intense Electromagnetic Fields
Alexander V. Kurilin
2002-10-13
The quantum field theory in the presence of classical background electromagnetic fields is reviewed. We give a pedagogical introduction to the Feynman-Furry method of describing non-perturbative interactions with very strong electromagnetic fields. A particular emphasis is given to the case of the plane-wave electromagnetic field for which the charged particles' wave functions and propagators are presented. Some general features of quantum processes proceeding in the intense electromagnetic background are argued. We also discuss the possibilities of searching new physics through the investigations of quantum phenomena induced by the strong electromagnetic environment.
Strong permanent magnet-assisted electromagnetic undulator
Halbach, Klaus (Berkeley, CA)
1988-01-01
This invention discloses an improved undulator comprising a plurality of electromagnet poles located along opposite sides of a particle beam axis with alternate north and south poles on each side of the beam to cause the beam to wiggle or undulate as it travels generally along the beam axis and permanent magnets spaced adjacent the electromagnetic poles on each side of the axis of said particle beam in an orientation sufficient to reduce the saturation of the electromagnet poles whereby the field strength of the electromagnet poles can be increased beyond the normal saturation levels of the electromagnetic poles.
Electromagnetically Induced Transparency with NMR
NASA Astrophysics Data System (ADS)
Son, Hyungbin; Kota, Murali; Chuang, Isaac; Steffen, Matthias; Judeinstein, Patrick
2003-03-01
Atomic, molecular and optical physics and quantum computing have a deep relationship, which we illustrate with an experimental study of electromagnetically induced transparency (EIT) in NMR. Recent results [1] illustrate how EIT can be used for light storage, and possibly as a memory for quantum states. Here, we demonstrate EIT operating at radiofrequency wavelengths, using the spin-7/2 nuclear quadrupole moment of Cesium and NMR quantum computation techniques. However, in contrast to the usual EIT experiment, we infer the transparency behavior by observing the spins instead of the transmitted electromagnetic radiation. We also provide alternative explanation of EIT as being an instance of quantum bang-bang control. References: 1. C. Liu, Z. Dutton, C. H. Behroozi, L. Vestergaard Hau, Nature 409, 490 (2001).
Electromagnetic instability in holographic QCD
Koji Hashimoto; Takashi Oka; Akihiko Sonoda
2014-12-25
Using the AdS/CFT correspondence, we calculate the vacuum decay rate for the Schwinger effect in confining large $N_{c}$ gauge theories. The instability is induced by the quark antiquark pair creation triggered by strong electromagnetic fields. The decay rate is obtained as the imaginary part of the Euler-Heisenberg effective Lagrangian evaluated from the D-brane action with a constant electromagnetic field in holographic QCD models such as the Sakai-Sugimoto model and the deformed Sakai-Sugimoto model. The decay rate is found to increase with the magnetic field parallel to the electric field, while it decreases with the magnetic field perpendicular to the electric field. We discuss generic features of a critical electric field as a function of the magnetic field and the QCD string tension in the Sakai-Sugimoto model.
The hidden geometry of electromagnetism
Yaron Hadad; Eliahu Cohen; Ido Kaminer; Avshalom C. Elitzur
2015-03-03
Nearly all field theories suffer from singularities when particles are introduced. This is true in both classical and quantum physics. Classical field singularities result in the notorious self-force problem, where it is unknown how the dynamics of a particle change when the particle interacts with its own (self) field. Self-force is a pressing issue and an active research topic in gravitational phenomena, as well as a source of controversies in classical electromagnetism. In this work, we study a hidden geometrical structure manifested by the electromagnetic field-lines that has the potential of eliminating all singularities from classical electrodynamics. We explore preliminary results towards a consistent way of treating both self- and external fields.
Electromagnetic moments of quasistable particle
Ledwig, Tim; Pascalutsa, Vladimir; Vanderhaeghen, Marc [Institut fuer Kernphysik, Johannes Gutenberg Universitaet Mainz, D-55099 Mainz (Germany)
2010-11-01
We deal with the problem of assigning electromagnetic moments to a quasistable particle (i.e., a particle with mass located at the particle's decay threshold). In this case, an application of a small external electromagnetic field changes the energy in a nonanalytic way, which makes it difficult to assign definitive moments. On the example of a spin-1/2 field with mass M{sub *} interacting with two fields of masses M and m, we show how a conventionally defined magnetic dipole moment diverges at M{sub *}=M+m. We then show that the conventional definition makes sense only when the values of the applied magnetic field B satisfy |eB|/2M{sub *}<<|M{sub *}-M-m|. We discuss implications of these results to existing studies in electroweak theory, chiral effective-field theory, and lattice QCD.
The hidden geometry of electromagnetism
NASA Astrophysics Data System (ADS)
Hadad, Y.; Cohen, E.; Kaminer, I.; Elitzur, A. C.
2015-07-01
Nearly all field theories suffer from singularities when particles are introduced. This is true in both classical and quantum physics. Classical field singularities result in the notorious self-force problem, where it is unknown how the dynamics of a particle change when the particle interacts with its own (self) field. Self-force is a pressing issue and an active research topic in gravitational phenomena, as well as a source of controversies in classical electromagnetism. In this work, we study a hidden geometrical structure manifested by the electromagnetic field-lines that has the potential of eliminating all singularities from classical electrodynamics. We explore preliminary results towards a consistent way of treating both self- and external fields.
Electromagnetic shielding in quantum metrology
Yao Jin; Hongwei Yu
2015-04-21
The dynamics of the quantum Fisher information of the parameters of the initial atomic state and atomic transition frequency is studied, in the framework of open quantum systems, for a static polarizable two-level atom coupled in the multipolar scheme to a bath of fluctuating vacuum electromagnetic fields without and with the presence of a reflecting boundary. Our results show that in the case without a boundary, the electromagnetic vacuum fluctuations always cause the quantum Fisher information of the initial parameters and thus the precision limit of parameter estimation to decrease. Remarkably, however, with the presence of a boundary, the quantum Fisher information becomes position and atomic polarization dependent, and as a result, it may be enhanced as compared to that in the case without a boundary and may even be shielded from the influence of the vacuum fluctuations in certain circumstances as if it were a closed system.
Electromagnetic tracking for catheter localization
NASA Astrophysics Data System (ADS)
Schneider, Mark R.
1999-07-01
A low frequency AC electromagnetic tracking system is presented that is capable of determining the position and orientation of a catheter tip. Advantages of using magnetic tracking for this application is that magnetic fields are non-ionizing and pass through the human body with minimal attenuation. Low frequency fields are used to mitigate the effects of eddy currents induced in conductive materials found in the environment. There are two significant differences between this and other magnetic tracking technologies, these being (1) the use of a single magnetic sensing coil for position and orientation determination and (2) the eliminating of range restrictions between the sensing antenna and the magnetic field generators. This paper will discuss the general theory of electromagnetic tracking, why it is that researchers have an intense interest for internal tracking and a comparison of the new and old tracking technologies. Some applications of this tracking technology will also be presented.
Electromagnetic Activation of Capillary Switches
NASA Astrophysics Data System (ADS)
Malouin, Bernie; Dayal, Rohan; Parsa, Leila; Hirsa, Amir
2008-11-01
By designing coupled droplet pairs with the appropriate length scale to promote surface tension as the dominant force, one can create bi-stable capillary switches. This bi-stability can be triggered by pressure pulses, surface chemistry, electroosmosis, or body forces. To exploit the latter, we designed a capillary switch with electromagnetic activation. The resulting setup consists of a sub-millimeter tube, overfilled with a ferrofluid, surrounded by a wire coil to generate a magnetic field. Evidence of this capillary switching will be presented along with some theoretical basis in fluid- and electro-dynamics. The approach may also be used to investigate other transport phenomena in electromagnetically-coupled microfluidic systems, including the relative effects of translational motion of the ferrofluid (both particles and solvent molecules) versus the rotational effects of the individual magnetic grains. These individually addressable capillary switches offer intriguing applications including high-speed adaptive optics, actuators at the microscale, and possible PCB integration.
Tuning up an electromagnetic accordion
Glanz, J.
1995-03-24
This article reports on research an electric `accordion` which could potentially effect the fields of radar, communications, and materials science as well as producing some insight into the behavior of the turbulent gases surrounding supernovae. The first working version of the electromagnetic accordian has been build and has produced `sounds` in the form of short bursts of radio waves. Scientists are trying to extend the range of this accordion to shorter wavelengths and pulse lengths. Description of the this work is given.
ELECTROMAGNETIC MODELING OF RETINAL PHOTORECEPTORS
Cahit Canbay
2008-01-01
Abstract—New electromagnetic models for the rods and,cones that are the,photoreceptors at,the,back,of the,retina are developed and simulated in order to explain the roles of dimension, geometrical structure, directional sensitivity and visual pigments of the photoreceptors in the reception of visible light. The rods and cones are modeled as uniform and quasi-tapered helical antennas, respectively. The results of the model study show
Electromagnetically induced spatial light modulation
L. Zhao; T. Wang; S. F. Yelin
2008-12-14
We theoretically report that, utilizing electromagnetically induced transparency (EIT), the transverse spatial properties of weak probe fields can be fast modulated by using optical patterns (e.g. images) with desired intensity distributions in the coupling fields. Consequently, EIT systems can function as high-speed optically addressed spatial light modulators. To exemplify our proposal, we indicate the generation and manipulation of Laguerre-Gaussian beams based on either phase or amplitude modulation in hot vapor EIT systems.
Laminated electromagnetic pump stator core
Fanning, A.W.
1995-08-08
A stator core for an electromagnetic pump includes a plurality of circumferentially abutting tapered laminations extending radially outwardly from a centerline axis to collectively define a radially inner bore and a radially outer circumference. Each of the laminations includes radially inner and outer edges and has a thickness increasing from the inner edge toward the outer edge to provide a substantially continuous path adjacent the circumference. This pump is used in nuclear fission reactors. 19 figs.
Electromagnetic radiation produces frame dragging
Herrera, L
2012-01-01
It is shown that for a generic electrovacuum spacetime, electromagnetic radiation produces vorticity of worldlines of observers in a Bondi--Sachs frame. Such an effect (and the ensuing gyroscope precession with respect to the lattice) which is a reminiscence of generation of vorticity by gravitational radiation, may be linked to the nonvanishing of components of the Poynting and the super--Poynting vectors on the planes othogonal to the vorticity vector. The possible observational relevance of such an effect is commented.
Electromagnetic radiation produces frame dragging
NASA Astrophysics Data System (ADS)
Herrera, L.; Barreto, W.
2012-09-01
It is shown that for a generic electrovacuum spacetime, electromagnetic radiation produces vorticity of worldlines of observers in a Bondi-Sachs frame. Such an effect (and the ensuing gyroscope precession with respect to the lattice) which is a reminiscence of generation of vorticity by gravitational radiation, may be linked to the nonvanishing of components of the Poynting and the super-Poynting vectors on the planes othogonal to the vorticity vector. The possible observational relevance of such an effect is commented upon.
Electromagnetic radiation produces frame dragging
L. Herrera; W. Barreto
2012-08-06
It is shown that for a generic electrovacuum spacetime, electromagnetic radiation produces vorticity of worldlines of observers in a Bondi--Sachs frame. Such an effect (and the ensuing gyroscope precession with respect to the lattice) which is a reminiscence of generation of vorticity by gravitational radiation, may be linked to the nonvanishing of components of the Poynting and the super--Poynting vectors on the planes othogonal to the vorticity vector. The possible observational relevance of such an effect is commented.
High performance electromagnetic simulation tools
Stephen D. Gedney; Keith W. Whites
1994-01-01
Army Research Office Grant #DAAH04-93-G-0453 has supported the purchase of 24 additional compute nodes that were installed in the Intel iPsC\\/860 hypercube at the Univesity Of Kentucky (UK), rendering a 32-node multiprocessor. This facility has allowed the investigators to explore and extend the boundaries of electromagnetic simulation for important areas of defense concerns including microwave monolithic integrated circuit (MMIC) design\\/analysis
Electromagnetism on anisotropic fractal media
NASA Astrophysics Data System (ADS)
Ostoja-Starzewski, Martin
2013-04-01
Basic equations of electromagnetic fields in anisotropic fractal media are obtained using a dimensional regularization approach. First, a formulation based on product measures is shown to satisfy the four basic identities of the vector calculus. This allows a generalization of the Green-Gauss and Stokes theorems as well as the charge conservation equation on anisotropic fractals. Then, pursuing the conceptual approach, we derive the Faraday and Ampère laws for such fractal media, which, along with two auxiliary null-divergence conditions, effectively give the modified Maxwell equations. Proceeding on a separate track, we employ a variational principle for electromagnetic fields, appropriately adapted to fractal media, so as to independently derive the same forms of these two laws. It is next found that the parabolic (for a conducting medium) and the hyperbolic (for a dielectric medium) equations involve modified gradient operators, while the Poynting vector has the same form as in the non-fractal case. Finally, Maxwell's electromagnetic stress tensor is reformulated for fractal systems. In all the cases, the derived equations for fractal media depend explicitly on fractal dimensions in three different directions and reduce to conventional forms for continuous media with Euclidean geometries upon setting these each of dimensions equal to unity.
Electromagnetic Effects in SDF Explosions
Reichenbach, H; Neuwald, P; Kuhl, A L
2010-02-12
The notion of high ion and electron concentrations in the detonation of aluminized explosive mixtures has aroused some interest in electro-magnetic effects that the SDF charges might generate when detonated. Motivated by this interest we have started to investigate whether significant electro-magnetic effects show up in our small-scale experiments. However, the design of instrumentation for this purpose is far from straightforward, since there are a number of open questions. Thus the main aim of the feasibility tests is to find - if possible - a simple and reliable method that can be used as a diagnostic tool for electro-magnetic effects. SDF charges with a 0.5-g PETN booster and a filling of 1 g aluminum flakes have been investigated in three barometric bomb calorimeters with volumes ranging from 6.3 l to of 6.6 l. Though similar in volume, the barometric bombs differed in the length-to-diameter ratio. The tests were carried out with the bombs filled with either air or nitrogen at ambient pressure. The comparison of the test in air to those in nitrogen shows that the combustion of TNT detonation products or aluminum generates a substantial increase of the quasi-steady overpressure in the bombs. Repeated tests in the same configuration resulted in some scatter of the experimental results. The most likely reason is that the aluminum combustion in most or all cases is incomplete and that the amount of aluminum actually burned varies from test to test. The mass fraction burned apparently decreases with increasing aspect ratio L/D. Thus an L/D-ratio of about 1 is optimal for the performance of shock-dispersed-fuel combustion. However, at an L/D-ratio of about 5 the combustion still yields appreciable overpressure in excess of the detonation. For a multi-burst scenario in a tunnel environment with a number of SDF charges distributed along a tunnel section a spacing of 5 tunnel diameter and a fuel-specific volume of around 7 l/g might provide an acceptable compromise between optimizing the combustion performance and keeping the number of elementary charges low. Further tests in a barometric bomb calorimeter of 21.2 l volume were performed with four types of aluminum. The mass fraction burned in this case appeared to depend on the morphology of the aluminum particles. Flake aluminum exhibited a better performance than granulated aluminum with particle sizes ranging from below 25 {micro}m to 125 {micro}m for the coarsest material. In addition, a feasibility study on electro-magnetic effects from SDF charges detonated in a tunnel has been performed. A method was developed to measure the local, unsteady electro-conductivity in the detonation/combustion products cloud. This method proved to yield reproducible results. A variety of methods were tested with regard to probing electro-magnetic pulses from the detonation of SDF charges. The results showed little reproducibility and were small compared to the effect from pulsed high voltage discharges of comparatively small energy (around 32 J). Thus either no significant electromagnetic pulse is generated in our small-scale tests or the tested techniques have to be discarded as too insensitive or too limited in bandwidth to detect possibly very high frequency electro-magnetic disturbances.
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
[Medical implantable devices and electromagnetic compatibility].
Andrivet, P
2003-04-01
Continuing progress in medicine has led to a corresponding population growth among the elderly population resulting in an increase in the number of patients with active implanted medical devices. At the same time, there continues to be a proliferation of electromagnetic wave sources within our technological environment. The coexistence of implanted active medical devices and environmental electromagnetic waves requires particular attention in order to avoid electromagnetic interference. For this reason, experts are more and more involved in writing specific manufacturing standards. PMID:12741334
Scalar invariants in gravitational and electromagnetic fields
Zihua Weng
2009-06-22
The paper discusses some scalar invariants in the gravitational field and electromagnetic field by means of the characteristics of the quaternions. When we emphasize some definitions of quaternion physical quantities, the speed of light, mass density, energy density, power density, charge density, and spin magnetic moment density etc. will remain the same respectively in the gravitational and electromagnetic fields under the coordinate transformation. The results explain why there are some relationships among different invariants in the gravitational and electromagnetic fields.
Thin sheet casting with electromagnetic pressurization
Walk, Steven R. (Winterport, ME); Slepian, R. Michael (Pittsburgh, PA); Nathenson, Richard D. (Pittsburgh, PA); Williams, Robert S. (Fairfield, OH)
1991-01-01
An apparatus, method and system for the casting of thin strips or strips of metal upon a moving chill block that includes an electromagnet located so that molten metal poured from a reservoir onto the chill block passes into the magnetic field produced by the electromagnet. The electromagnet produces a force on the molten metal on said chill block in the direction toward said chill block in order to enhance thermal contact between the molten metal and the chill block.
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 ...
Broadband electromagnetic cloaking of long cylindrical objects.
Tretyakov, Sergei; Alitalo, Pekka; Luukkonen, Olli; Simovski, Constantin
2009-09-01
Electromagnetic cloaks are devices that make objects undetectable for probing with electromagnetic waves. The known realizations of transformational-optics cloaks require materials with exotic electromagnetic properties and offer only limited performance in narrow frequency bands. Here, we demonstrate a wideband and low-loss cloak whose operation is not based on the use of exotic electromagnetic materials, which are inevitably dispersive and lossy. Instead, we use a simple structure made of metal layers. In this Letter, we present an experimental demonstration of cloaking for microwaves and simulation results for cloaking in the visible range. PMID:19792314
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.
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, ...
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.
Field equations of electromagnetic and gravitational fields
Zihua Weng
2009-05-16
The paper studies the validity of Maxwell equation in the case for coexistence of electromagnetic field and gravitational field. With the algebra of quaternions, the Newton's law of gravitation is the same as that in classical theory of gravitational field. Meanwhile the Maxwell equation is identical with that in classical theory of electromagnetic field. And the related conclusions can be spread to the case for coexistence of electromagnetic field and gravitational field by the algebra of octonions. The study claims that Maxwell equation keeps unchanged in the case for coexistence of gravitational field and electromagnetic field, except for the direction of displacement current.
Electromagnetic compatibility of nuclear power plants
Cabayan, H.S.
1983-01-01
Lately, there has been a mounting concern about the electromagnetic compatibility of nuclear-power-plant systems mainly because of the effects due to the nuclear electromagnetic pulse, and also because of the introduction of more-sophisticated and, therefore, more-susceptible solid-state devices into the plants. Questions have been raised about the adequacy of solid-state-device protection against plant electromagnetic-interference sources and transients due to the nuclear electromagnetic pulse. In this paper, the author briefly reviews the environment, and the coupling, susceptibility, and vulnerability assessment issues of commercial nuclear power plants.
Electromagnetic fields in fractal continua
NASA Astrophysics Data System (ADS)
Balankin, Alexander S.; Mena, Baltasar; Patiño, Julián; Morales, Daniel
2013-04-01
Fractal continuum electrodynamics is developed on the basis of a model of three-dimensional continuum ?D3?E3 with a fractal metric. The generalized forms of Maxwell equations are derived employing the local fractional vector calculus related to the Hausdorff derivative. The difference between the fractal continuum electrodynamics based on the fractal metric of continua with Euclidean topology and the electrodynamics in fractional space F? accounting the fractal topology of continuum with the Euclidean metric is outlined. Some electromagnetic phenomena in fractal media associated with their fractal time and space metrics are discussed.
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.
Quantum modulation against electromagnetic interference
Juan Carlos Garcia-Escartin
2014-11-26
Periodic signals in electrical and electronic equipment can cause interference in nearby devices. Randomized modulation of those signals spreads their energy through the frequency spectrum and can help to mitigate electromagnetic interference problems. The inherently random nature of quantum phenomena makes them a good control signal. I present a quantum modulation method based on the random statistics of quantum light. The paper describes pulse width modulation schemes where a Poissonian light source acts as a random control that spreads the energy of the potential interfering signals. I give an example application for switching-mode power supplies and comment the further possibilities of the method.
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 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.
Electromagnetic fields and health outcomes.
Knave, B
2001-09-01
Over the past two decades, there has been increasing interest in the biological effects and possible health outcomes of weak, low-frequency electric and magnetic fields. Epidemiological studies on magnetic fields and cancer, reproduction and neurobehavioural reactions have been presented. More recently, neurological, degenerative and heart diseases have also been reported to be related to such electromagnetic fields. Furthermore, the increased use of mobile phones worldwide has focussed interest on the possible effects of radiofrequency fields of higher frequencies. In this paper, a summary is given on electromagnetic fields and health outcomes and what policy is appropriate--"no restriction to exposure", "prudent avoidance" or "expensive interventions"? The results of research studies have not been unambiguous; studies indicating these fields as being a health hazard have been published and so were studies indicating no risk at all. In "positive" studies, different types of effects have been reported despite the use of the same study design, e.g., in epidemiological cancer studies. There are uncertainties as to exposure characteristics, e.g., magnetic field frequency and exposure intermittence, and not much is known about possible confounding or effect-modifying factors. The few animal cancer studies reported have not given much help in risk assessment; and in spite of a large number of experimental cell studies, no plausible and understandable mechanisms have been presented by which a carcinogenic effect could be explained. Exposure to electromagnetic fields occurs everywhere: in the home, at work, in school, etc. Wherever there are electric wires, electric motors and electronic equipment, electromagnetic fields are created. This is one of the reasons why exposure assessment is difficult. For epidemiologists, the problems is not on the effect side as registers of diseases exist in many countries today. The problem is that epidemiologists do not know the relevant exposure characteristics to be used in their studies. In international guidelines, limits for restrictions of field exposure are several orders of magnitude above what can be measured from overhead power lines and found in "electrical" occupations. These guidelines emphasize that the state of scientific knowledge today does not warrant limiting exposure levels for the public and the work force, and that further data are required to confirm whether health hazards are present. In some countries, however, the "principle of caution" or "prudent avoidance" has been adopted; meaning the low-cost avoidance of unnecessary exposure as long as there is scientific uncertainty about its health effects. PMID:11603131
Key, Kerry
Special Section -- Marine Controlled-Source Electromagnetic Methods 2D marine controlled-source electromagnetic modeling: Part 1 -- An adaptive finite-element algorithm Yuguo Li1 and Kerry Key1 ABSTRACT In Part of the frequency-domain, ma- rine controlled-source electromagnetic CSEM response of a 2D conductivity structure
Melamed, Timor
Progress In Electromagnetics Research, Vol. 114, 317332, 2011 PULSED BEAM EXPANSION-based pulsed-beams expansion of planar aperture time- dependent electromagnetic fields. The propagating field-beam waveobjects over the frame spectral lattice. Explicit asymptotic expressions for the electromagnetic pulsed
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.
Electromagnetic scattering from turbulent plasmas
Resendes, D.G. Instituto Superior Tecnico, Rua Rovisco Pais, Lisboa )
1992-11-15
A self-consistent multiple-scattering theory of vector electromagnetic waves scattered from a turbulent plasma is presented. This approach provides a general and systematic treatment to all orders in turbulence of the scattering of electromagnetic waves in terms of the properties of the turbulent structure of the scattering system and is applicable in the full regime from underdense to overdense plasmas. To illustrate the theory, a plasma consisting of a finite number density of discrete scatterers with a simple geometry and statistical properties is chosen. In this approach the exact solution for a single scatterer is obtained first. From it the configuration-dependent solution for {ital N} scatterers is constructed. Rather than solving explicitly for this solution and then averaging, the averaging operation will be taken first in order to find an approximate equation obeyed by the mean or coherent field. The coherent and incoherent scattering are then determined in terms of the coherent field and the backscatter is evaluated. The coherent and incoherent scattering, our principal results, are expressed in a plane-wave basis in a form suitable for numerical computation. A number of interesting phenomena which may readily be incorporated into the theory are indicated.
Adaptive Multiscale Electromagnetic Particle Simulations
NASA Astrophysics Data System (ADS)
Omelchenko, Y. A.; Karimabadi, H.; Brown, M.; Catalyurek, U. V.; Saule, E.
2010-11-01
Hybrid (massless fluid electrons, kinetic ions) and full electromagnetic PIC simulations have recently emerged as powerful computational tools for predicting energetic particle transport in large-scale plasma configurations. Multiple time and length scales associated with plasma and magnetic field inhomogeneities put severe restrictions on the timestep and mesh resolution in these applications. We present two approaches intended to relieve these issues. An asynchronous hybrid code, HYPERS discards traditional time stepping in favor of Discrete-Event Simulation (DES). DES adaptively selects time increments for individual particles and local electromagnetic fields by limiting their per-update changes. HYPERS has been designed to simulate 3D compact fusion devices (such as the SSX experiment at Swarthmore) and interactions of streaming plasmas with obstacles. To validate this new code, we compare results from 2D HYPERS simulations with those obtained with a traditional (time-stepped) hybrid code. We also discuss a novel subgridding (EMPOWER) algorithm for full EM-PIC simulations and demonstrate its efficiency on test problems. Both codes are being geared towards peta/exa-scale computer architectures. We report our undergoing efforts on developing efficient dynamic load-balancing strategies for parallel production runs.
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
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
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)
Symmetries and currents of massless neutrino fields, electromagnetic and
Pohjanpelto, Juha
Symmetries and currents of massless neutrino fields, electromagnetic interesting cases, are also presented in tensorial form for electromagnetic and graviton fields, respectively de- scribing neutrino fields, electromagnetic fields and graviton fields (i.e., linearized
THE ELECTROMAGNETIC INVERSE SCATTERING PROBLEM FOR PARTIALLY COATED LIPSCHITZ DOMAINS
Cakoni, Fioralba
THE ELECTROMAGNETIC INVERSE SCATTERING PROBLEM FOR PARTIALLY COATED LIPSCHITZ DOMAINS FIORALBA electromagnetic plane wave and the electric far field pattern of the scattered wave. A justification is given method. Key words. Electromagnetic inverse scattering, Lipschitz domain, mixed boundary conditions
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
UNIVERSITY OF CALIFORNIA Three Dimensional Electromagnetic Field Simulation of
Mease, Kenneth D.
UNIVERSITY OF CALIFORNIA IRVINE Three Dimensional Electromagnetic Field Simulation of Integrated..........................................................................................4 I.3 3D ELECTROMAGNETIC FIELD SIMULATION.....................................................6 I.4 .................................................................................35 V. QUALITATIVE STUDY OF THE ELECTROMAGNETIC FIELDS PRESENT IN MIM CAPACITORS
The Graz seismo-electromagnetic VLF facility
K. Schwingenschuh; M. Boudjada; A. Rozhnoi; M. Solovieva; O. Molchanov; M. Stachel; G. Prattes; Oe. Aydogar; H. U. Eichelberger; P. F. Biagi
2009-01-01
We present the Graz VLF facility which is part of a ongoing European ground-based project for the study of seismo-electromagnetic phenomena. There is a close cooperation with ground-based VLF\\/LF networks in Japan and Russia and with satellite based seismo-electromagnetic projects like DEMETER. The receiver of the Graz VLF station has been provided by the \\
Maximal efficiency of an electromagnetic drive
Smelyagin
1988-01-01
The authors derive an analytic expression for the maximum efficiency of an electromagnetic drive for which the inductance varies according to a hyperbolic law and they determine the conditions under which it is achieved.The equations for hammers, stamps, pumps, tampers, vibrator agitators, and other machines with an electromagnetic drive are shown. It is shown that at the initial instant the
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…
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)
Advanced electromagnetic methods for aerospace vehicles
Constantine A. Balanis; Weimin Sun; El-Budawy El-Sharawy; James T. Aberle; Craig R. Birtcher; Jian Peng; Panayiotis A. Tirkas
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
Coupled seismic and electromagnetic wave propagation
M. D. Schakel
2011-01-01
Coupled seismic and electromagnetic wave propagation is studied theoretically and experimentally. This coupling arises because of the electrochemical double layer, which exists along the solid-grain\\/fluid-electrolyte boundaries of porous media. Within the double layer, charge is redistributed, creating an excess electrical charge in the fluid along the boundary. Electrokinetic theory describes coupled seismic and electromagnetic wave propagation. It predicts that seismic
Himass electromagnetic launcher at Los Alamos
Zimmermann, E.L.; Fowler, C.M.; Foley, E.; Parker, J.V.
1986-01-01
The HIMASS electromagnetic launcher is a unique large-bore, large-mass railgun driven by a helical flux compression generator. Two experiments were conducted at 3 to 4 MA current levels. The objective of the experiments was to study the effects of scaling, ablation, and material parameters on electromagnetic launcher performance. Data from these two experiments are presented.
Pulsed power requirements for electromagnetic launchers
Weldon, W.F.; Woodson, H.H.
1984-03-01
Both linear (railgun) and coaxial (mass driver, etc.) electromagnetic launchers (EMLs) are treated as time-varying impedances to determine the relationships between acceleration force, payload velocity, and power supply voltage and current. These relationships are then examined in the light of electromagnetic parameters associated with each EML type to establish a basis for determining and comparing power supply requirements for various EMLs.
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…
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)
Relativistic diffusive motion in thermal electromagnetic fields
Z. Haba
2013-04-07
We discuss relativistic dynamics in a random electromagnetic field which can be considered as a high temperature limit of the quantum electromagnetic field in a heat bath (cavity) moving with a uniform velocity w. We derive diffusion approximation for the particle's dynamics generalizing the diffusion of Schay and Dudley. It is shown that the Juttner distribution is the equilibrium state of the diffusion.
Surveying the Earth's Electromagnetic Environment From Space
Michel Parrot; Dimitar Ouzounov
2006-01-01
The scientific objectives of DEMETER (Detection of Electro-Magnetic Emissions Transmitted from Earthquake Regions) are the detection and characterization of the ionospheric perturbations associated with natural phenomena (such as earthquakes, volcanic eruptions, tsunamis) or with anthropogenic activities. To achieve these objectives, the microsatellite, which was launched at the end of June 2004, surveys the Earth's electromagnetic environment. DEMETER is the first
Electromagnetic models of the lightning return stroke
Yoshihiro Baba; Vladimir A. Rakov
2007-01-01
Lightning return-stroke models are needed for specifying the source in studying the production of transient optical emission (elves) in the lower ionosphere, the energetic radiation from lightning, and characterization of the Earth's electromagnetic environment, as well as studying lightning interaction with various objects and systems. Reviewed here are models based on Maxwell's equations and referred to as electromagnetic models. These
Axial Electromagnetic Force Density in Mpd Thrusters
T. S. Sheshadri
1992-01-01
An MPD thruster formulation involving coupled aerothermodynamic-electromagnetic equations and including viscous effects is developed and solved. The electromagnetic force density distribution in the thruster interior is studied. Axial force densities are found to be largest on the cathode longitudinal surface. Very large force densities are found at the cathode upstream end and this is attributed to large values of the
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,…
Ultimate Energy Densities for Electromagnetic Pulses
Mankei Tsang
2008-03-06
The ultimate electric and magnetic energy densities that can be attained by bandlimited electromagnetic pulses in free space are calculated using an ab initio quantized treatment, and the quantum states of electromagnetic fields that achieve the ultimate energy densities are derived. The ultimate energy densities also provide an experimentally accessible metric for the degree of localization of polychromatic photons.
The Good, the Bad and the Electromagnet
NSDL National Science Digital Library
2014-09-18
Using plastic straws, wire, batteries and iron nails, student teams build and test two versions of electromagnets—one with and one without an iron nail at its core. They test each magnet's ability pick up loose staples, which reveals the importance of an iron core to the magnet's strength. Students also learn about the prevalence and importance of electromagnets in their everyday lives.
Chaos Experiments Wave Chaos and Electromagnetic
Anlage, Steven
Chaos Experiments Wave Chaos and Electromagnetic Interference in Enclosures ·Faculty: Steven M;Electromagnetic Coupling in Computer Circuits connectors cables circuit boards Integrated circuits Schematic can be said about coupling without solving in detail the complicated EM problem ? · Wave Chaos Chaotic
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?
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.
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
NASA Astrophysics Data System (ADS)
Franklin, Jerrold
2014-09-01
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 scattering by impedance structures
NASA Technical Reports Server (NTRS)
Balanis, Constantine A.; Griesser, Timothy
1987-01-01
The scattering of electromagnetic waves from impedance structures is investigated, and current work on antenna pattern calculation is presented. A general algorithm for determining radiation patterns from antennas mounted near or on polygonal plates is presented. These plates are assumed to be of a material which satisfies the Leontovich (or surface impedance) boundary condition. Calculated patterns including reflection and diffraction terms are presented for numerious geometries, and refinements are included for antennas mounted directly on impedance surfaces. For the case of a monopole mounted on a surface impedance ground plane, computed patterns are compared with experimental measurements. This work in antenna pattern prediction forms the basis of understanding of the complex scattering mechanisms from impedance surfaces. It provides the foundation for the analysis of backscattering patterns which, in general, are more problematic than calculation of antenna patterns. Further proposed study of related topics, including surface waves, corner diffractions, and multiple diffractions, is outlined.
The CLAS Forward Electromagnetic Calorimeter
M. Amarian; Geram Asryan; Kevin Beard; Will Brooks; Volker Burkert; Tom Carstens; Alan Coleman; Raphael Demirchyan; Yuri Efremenko; Hovanes Egiyan; Kim Egiyan; Herb Funsten; Vladimir Gavrilov; Kevin L. Giovanetti; R.M. Marshall; Berhard Mecking; R.C. Minehart; H. Mkrtchan; Mavrik Ohandjanyan; Youri Sharabian; L.C. Smith; Stepan Stepanyan; W.A. Stephens; T.Y. Tung; Carl Zorn
2001-05-01
The CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab utilizes six iron-free superconducting coils to provide an approximately toroidal magnetic field. The six sectors are instrumented individually to form six independent spectrometers. The forward region (8deg < (theta) < 45deg) of each sector is equipped with a lead-scintillator electromagnetic sampling calorimeter (EC), 16 radiation lengths thick, using a novel triangular geometry with stereo readout. With its good energy and position resolution, the EC is used to provide the primary electron trigger for CLAS. It is also used to reject pions, reconstruct pi-0 and eta decays and detect neutrons, This paper treats the design, construction and performance of the calorimeter.
Ultrarelativistic electromagnetic pulses in plasmas
Ashour-Abdalla, M.; Leboeuf, J.N.; Tajima, T.; Dawson, J.M.; Kennel, C.F.
1981-04-01
We study through computer simulation the physical processes of a linearly polarized electromagnetic pulse of highly relativistic amplitude (eE/m..omega..c>>1) in an underdense plasma accelerating particles to very high energies. We consider first an electron-positron plasma. 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 pistonlike 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 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.
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.
ELVIS - ELectromagnetic Vector Information Sensor
J. E. S. Bergman; L. Åhlén; O. Stål; B. Thidé; S. Ananthakrishnan; J. -E. Wahlund; R. L. Karlsson; W. Puccio; T. D. Carozzi; P. Kale
2005-09-29
The ELVIS instrument was recently proposed by the authors for the Indian Chandrayaan-1 mission to the Moon and is presently under consideration by the Indian Space Research Organisation (ISRO). The scientific objective of ELVIS is to explore the electromagnetic environment of the moon. ELVIS samples the full three-dimensional (3D) electric field vector, E(x,t), up to 18 MHz, with selective Nyqvist frequency bandwidths down to 5 kHz, and one component of the magnetic field vector, B(x,t), from a few Hz up to 100 kHz.As a transient detector, ELVIS is capable of detecting pulses with a minimum pulse width of 5 ns. The instrument comprises three orthogonal electric dipole antennas, one magnetic search coil antenna and a four-channel digital sampling system, utilising flexible digital down conversion and filtering together with state-of-the-art onboard digital signal processing.
Electromagnetic Structure of Light Nuclei
NASA Astrophysics Data System (ADS)
Schiavilla, Rocco
1998-11-01
The electromagnetic structure of the ground- and low-lying-states of the A=2-6 nuclei is reviewed. Predictions for the A(q) and B(q) structure functions and tensor polarization of the deuteron, the charge and magnetic form factors of ^3H and 3He, and the ^6Li ground-state longitudinal and transverse form factors as well as transition form factors to the first four excited states are presented. The calculations are based on a realistic Hamiltonian consisting of the Argonne v_18 two-nucleon and Urbana-IX three-nucleon interactions, and use charge and current operators with one-, two- and many-body components, leading terms of which are constructed consistently with the two- and three-nucleon interactions. A critical comparison with other predictions, where available, will be made.
Spatially Dependent Electromagnetically Induced Transparency
NASA Astrophysics Data System (ADS)
Radwell, N.; Clark, T. W.; Piccirillo, B.; Barnett, S. M.; Franke-Arnold, S.
2015-03-01
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.
Dressing the electromagnetic nucleon current
Haberzettl, H.; Huang, F.; Nakayama, K.
2011-06-15
A field-theory-based approach to pion photoproduction off the nucleon is used to derive a microscopically consistent formulation of the fully dressed electromagnetic nucleon current in an effective Lagrangian formalism. It is shown how the rigorous implementation of local gauge invariance at all levels of the reaction dynamics provides equations that lend themselves to practically manageable truncations of the underlying nonlinearities of the problem. The requirement of consistency also suggests a novel way of treating the pion photoproduction problem. Guided by a phenomenological implementation of gauge invariance for the truncated equations that has proved successful for pion photoproduction, an expression for the fully dressed nucleon current is given that satisfies the Ward-Takahashi identity for a fully dressed nucleon propagator as a matter of course. Possible applications include meson photo- and electroproduction processes, bremsstrahlung, Compton scattering, and ee{sup '} processes off nucleons.
Dressing the electromagnetic nucleon current
H. Haberzettl; F. Huang; K. Nakayama
2011-03-10
A field-theory-based approach to pion photoproduction off the nucleon is used to derive a microscopically consistent formulation of the fully dressed electromagnetic nucleon current in an effective Lagrangian formalism. It is shown how the rigorous implementation of local gauge invariance at all levels of the reaction dynamics provides equations that lend themselves to practically manageable truncations of the underlying nonlinearities of the problem. The requirement of consistency also suggests a novel way of treating the pion photoproduction problem. Guided by a phenomenological implementation of gauge invariance for the truncated equations that has proved successful for pion photoproduction, an expression for the fully dressed nucleon current is given that satisfies the Ward-Takahashi identity for a fully dressed nucleon propagator as a matter of course. Possible applications include meson photo- and electroproduction processes, bremsstrahlung, Compton scattering, and $ee'$ processes off nucleons.
Electromagnetic modeling of plasmonic nanostructures
NASA Astrophysics Data System (ADS)
Pavaskar, Prathamesh
In this thesis, plasmonic properties of metal nanostructures are investigated by electromagnetic simulations using the finite difference time domain (FDTD) method. Chapter 1 covers the background knowledge required to read this thesis. It talks about the fundamentals of the FDTD method, the physics of plasmonics and a brief description of photocatalysis. In chapter 2, we perform optimization of plasmonic nanoparticle geometries. An iterative optimization algorithm is used to determine the configuration of the nanoparticles that gives the maximum electric field intensity at the center of the cluster. We observe that the optimum configurations of these clusters have mirror symmetry about the axis of planewave propagation, but are otherwise non-symmetric and non-intuitive. The maximum field intensity is found to increase monotonically with the number nanoparticles in the cluster, producing intensities that are 2500 times larger than the incident electromagnetic field. In chapter 3, evaporated thin films are imaged with high resolution transmission electron microscopy (HRTEM), to reveal the structure of the semicontinuous metal island film with sub-nm resolution. The electric field distributions and the absorption spectra of these semicontinuous island film geometries are calculated using the finite difference time domain (FDTD) method and compared with the experimentally measured absorption spectra. In addition to that, we calculate the SERS enhancement factors and photocatalytic enhancement factors of these films. We also study the effect of annealing on these films, which results in a large reduction in electric field strength due to increased nanoparticle spacing. In chapter 4, we study the effects of surrounding nanoparticles on a plasmonic hot spot. From our simulations, we show that the surrounding film contributes significantly to the electric field intensity at the hot spot by focusing energy to it. Widening of the gap size causes a decrease in the intensity at the hot spot. However, these island-like nanoparticle hot spots are shown to be robust to gap size than nanoparticle dimer geometries, studied previously. In fact, the main factor in determining the hot spot intensity is the focusing effect of the surrounding nano-islands. In chapter 5, we demonstrate plasmon-enhanced photocatalytic water splitting, and reduction of CO2 with H2O to form hydrocarbon fuels. Under visible illumination, we observe enhancements of up to 66X in the photocatalytic splitting of water in TiO2 with the addition of Au nanoparticles. We also perform a systematic study of the mechanisms of Au nanoparticle/TiO 2-catalyzed photoreduction of CO2 and water vapor over a wide range of wavelengths. In this case, under visible light illumination, we observe a 24-fold enhancement in the photocatalytic activity due to the intense local electromagnetic fields created by the surface plasmons of the Au nanoparticles. Above the plasmon resonance, under ultraviolet radiation we observe a reduction in the photocatalytic activity. Electromagnetic simulations indicate that the improvement of photocatalytic activity in the visible range is caused by the local electric field enhancement near the TiO2 surface, rather than by the direct transfer of charge between the two materials. In chapter 6, I will talk about a method for fabricating arrays of plasmonic nanoparticles with separations on the order of 1nm using an angle evaporation technique. High resolution transmission electron microscopy (HRTEM) is used to resolve the small separations achieved between nanoparticles fabricated on thin SiN membranes. These nearly touching metal nanoparticles produce extremely high electric field intensities when irradiated with laser light. We perform surface enhanced Raman spectroscopy (SERS) a non-resonant dye molecule (p-ATP) deposited on the nanoparticle arrays using confocal micro-Raman spectroscopy. Our results show significant enhancement when the incident laser is polarized parallel to the axis of the nanoparticle pairs, whereas no enhancement is observed for the p
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-gravitational energy systems
NASA Technical Reports Server (NTRS)
Schatten, K. H.
1981-01-01
Two methods are considered to 'tap' the earth's rotational energy. This ancient 'collapsed gravitational energy' exceeds the earth-lunar binding energy. One involves an orbiting 'electromagnetic-gravitational' coupling system whereby the earth's rotation, with its nonuniform mass distribution, first uses gravity to add orbital energy to a satellite, similar to a planetary 'flyby'. The second stage involves enhanced satellite 'drag' as current-carrying coils withdraw the added orbital energy as they pass through the earth's nonuniform magnetic field. A second more direct method couples the earth's rotational motion using conducting wires moving through the noncorotating part (ionospheric current systems) of the geomagnetic field. These methods, although not immediately feasible, are considerably more efficient than using pure gravitational coupling to earth-moon tides.
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
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.
Electromagnetically induced frame dragging around astrophysical objects
NASA Astrophysics Data System (ADS)
Gutiérrez-Ruiz, Andrés F.; Pachón, Leonardo A.
2015-06-01
Frame dragging (Lense-Thirring effect) is generally associated with rotating astrophysical objects. However, it can also be generated by electromagnetic fields if electric and magnetic fields are simultaneously present. In most models of astrophysical objects, macroscopic charge neutrality is assumed and the entire electromagnetic field is characterized in terms of a magnetic dipole component. Hence, the purely electromagnetic contribution to the frame dragging vanishes. However, strange stars may possess independent electric dipole and neutron stars independent electric quadrupole moments that may lead to the presence of purely electromagnetic contributions to the frame dragging. Moreover, recent observations have shown that in stars with strong electromagnetic fields, the magnetic quadrupole may have a significant contribution to the dynamics of stellar processes. As an attempt to characterize and quantify the effect of electromagnetic frame dragging in these kinds of astrophysical objects, an analytic solution to the Einstein-Maxwell equations is constructed here on the basis that the electromagnetic field is generated by the combination of arbitrary magnetic and electric dipoles plus arbitrary magnetic and electric quadrupole moments. The effect of each multipole contribution on the vorticity scalar and the Poynting vector is described in detail. Corrections on important quantities such the innermost stable circular orbit (ISCO) and the epicyclic frequencies are also considered.
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.
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.
Alternative expression for the electromagnetic Lagrangian
Saldanha, Pablo L
2015-01-01
We propose an alternative expression for the Lagrangian density that governs the interaction of a charged particle with external electromagnetic fields. The proposed Lagrangian is written in terms of the local superposition of the particle fields with the applied electromagnetic fields, not in terms of the particle charge and of the electromagnetic potentials as is usual. The total Lagrangian for a set of charged particles assumes a simple elegant form with the alternative formulation, giving an aesthetic support for it. The proposed Lagrangian is equivalent to the traditional one in their domain of validity and provides an interesting description of the Aharonov-Bohm effect.
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.
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.
Invariants in electromagnetic and gravitational adjoint fields
Zihua Weng
2009-06-22
The paper discusses the impact of adjoint fields on the conservation laws in the gravitational field and electromagnetic field, by means of the characteristics of octonions. When the adjoint field can not be neglected, it will cause the predictions to departure slightly from the conservation laws, which include mass continuity equation, charge continuity equation, and conservation of spin. The adjoint field of electromagnetic field has an effect on conservation of mass, and that of gravitational field on conservation of charge. The inferences explain how the adjoint field influences some conservation laws in the gravitational field and electromagnetic field.
Scattering of electromagnetic waves into plasma oscillations via plasma particles
A. T. Lin; J. M. Dawson
1975-01-01
A plasma subjected to an intense electromagnetic wave can exhibit a large number of parametric instabilities. An interesting example which has received little attention is the decay of the electromagnetic wave into a plasma oscillation with the excess energy and momentum being carried off by electrons. This process has been simulated on a one?and?two?halves dimensional electromagnetic code. The incident electromagnetic
Scattering of electromagnetic waves into plasma oscillations via plasma particles
A. T. Lin; J. M. Dawson
1975-01-01
A plasma subjected to an intense electromagnetic wave can exhibit a large number of parametric instabilities. An interesting example which has received little attention is the decay of the electromagnetic wave into a plasma oscillation with the excess energy and momentum being carried off by electrons. This process has been simulated on a one-and-two-halves dimensional electromagnetic code. The incident electromagnetic
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
Micro-Electromagnetic Formation Flight of Satellite Systems Aya Sakaguchi
Micro-Electromagnetic Formation Flight of Satellite Systems by Aya Sakaguchi B.S. Mechanical;3 Micro-Electromagnetic Formation Flight of Satellite Systems by Aya Sakaguchi Submitted to the Department Electromagnetic formation flight (EMFF) investigates the concept of using electromagnets to provide the forces
Politècnica de Catalunya, Universitat
Scalability of the Channel Capacity of Electromagnetic NanonetworksScalability of the Channel Capacity of Electromagnetic NanonetworksScalability of the Channel Capacity of Electromagnetic NanonetworksScalability of the Channel Capacity of Electromagnetic Nanonetworks I. Llatser, A. CabellosI. Llatser, A. Cabellos
Title: Inverse Electromagnetic Problems Name: Gunther Uhlmann, Ting Zhou
Uhlmann, Gunther
Title: Inverse Electromagnetic Problems Name: Gunther Uhlmann, Ting Zhou Affil./Addr. 1: University/University of California Irvine/tzhouuw@gmail.com Inverse Electromagnetic Problems Introduction In this chapter we consider inverse boundary problems for electromagnetic waves. The goal is to determine the electromagnetic
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...
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.
SP-100 thermoelectric-electromagnetic pump review
NONE
1988-12-31
This report contains vugraphs of a presentation on thermoelectric-electromagnetic pumps. It contains: engineering drawings; summary of rectangular TEMP results and comparison with GE predictions; and results of optimization study.
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.
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.
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.
Standing electromagnetic solitons in degenerate relativistic plasmas
NASA Astrophysics Data System (ADS)
Mikaberidze, G.; Berezhiani, V. I.
2015-10-01
The existence of standing high frequency electromagnetic (EM) solitons in a fully degenerate overdense electron plasma is studied applying relativistic hydrodynamics and Maxwell equations. The stable soliton solutions are found in both relativistic and nonrelativistic degenerate plasmas.
Electromagnetic thrusters for spacecraft prime propulsion
NASA Technical Reports Server (NTRS)
Rudolph, L. K.; King, D. Q.
1984-01-01
The benefits of electromagnetic propulsion systems for the next generation of US spacecraft are discussed. Attention is given to magnetoplasmadynamic (MPD) and arc jet thrusters, which form a subset of a larger group of electromagnetic propulsion systems including pulsed plasma thrusters, Hall accelerators, and electromagnetic launchers. Mission/system study results acquired over the last twenty years suggest that for future prime propulsion applications high-power self-field MPD thrusters and low-power arc jets have the greatest potential of all electromagnetic thruster systems. Some of the benefits they are expected to provide include major reductions in required launch mass compared to chemical propulsion systems (particularly in geostationary orbit transfer) and lower life-cycle costs (almost 50 percent less). Detailed schematic drawings are provided which describe some possible configurations for the various systems.
Dynamic programming applied to electromagnetic satellite actuation
Eslinger, Gregory John
2013-01-01
Electromagnetic formation flight (EMFF) is an enabling technology for a number of space mission architectures. While much work has been done for EMFF control for large separation distances, little work has been done for ...
Electromagnetic 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.
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.
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.
Medical applications of electromagnetic fields
NASA Astrophysics Data System (ADS)
Lai, Henry C.; Singh, Narendra P.
2010-04-01
In this article, we describe two possible applications of low-intensity non-ionizing electromagnetic fields (EMF) for the treatment of malaria and cancer, respectively. In malaria treatment, a low-intensity extremely-low frequency magnetic field can be used to induce vibration of hemozoin, a super-paramagnetic polymer particle, inside malaria parasites. This disturbance could cause free radical and mechanical damages leading to the death of the parasite. This concept has been tested in vitro on malaria parasites and found to be effective. This may provide a low cost effective treatment for malaria infection in humans. The rationale for cancer treatment using low-intensity EMF is based on two concepts that have been well established in the literature: (1) low-intensity non-thermal EMF enhances cytotoxic free radicals via the iron-mediated Fenton reaction; and (2) cancer cells have higher amounts of free iron, thus are more susceptible to the cytotoxic effects of EMF. Since normal cells contain minimal amount of free iron, the effect would be selectively targeting cancer cells. Thus, no adverse side effect would be expected as in traditional chemotherapy and radiation therapy. This concept has also been tested on human cancer cell and normal cells in vitro and proved to be feasible.
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.
Wavefield transform of electromagnetic fields
Lee, K.H.; Xie, G.Q. [Lawrence Berkeley Lab., CA (United States); Habashy, T.M.; Torres-Verdin, C. [Schlumberger-Doll Research, Ridgefield, CT (United States)
1994-12-31
One of the recent developments in electromagnetic (EM) methods for crosshole conductivity imaging involves transformation of diffuse EM fields to wavefields (Lee and Xie, 1993). In this approach the EM fields are first transformed to wavefields. The velocity of the wavefield and the electrical conductivity are related by a simple formula. Using traveltime obtained from the transformed wavefield a ray tomography would be carried out for the wavefield velocity and then the electrical conductivity. From the transformed wavefield only the traveltime is used for the tomographic imaging. This paper examines numerical methods for obtaining travel times by transforming either the time- or the frequency-domain data to wavefields. The number of sample data used for the transform can be as little as ten for the frequency-domain approach and twenty five for the time-domain approach. The accuracy in the traveltime obtained this way seems within one percent provided that the data are sufficiently accurate. The transform originally involves the solution of a Fredholm integral equation of the first kind. Predictably, with lesser amount of data the numerical process becomes more ill-posed.
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 momentum conservation in media
Brevik, Iver [Department of Energy and Process Engineering, Norwegian University of Science and Technology, N-7491 Trondheim (Norway); Ellingsen, Simen A., E-mail: simen.a.ellingsen@ntnu.no [Department of Energy and Process Engineering, Norwegian University of Science and Technology, N-7491 Trondheim (Norway)
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.
Inertia, Electromagnetism and Fluid Dynamics
NASA Astrophysics Data System (ADS)
Martins, Alexandre A.; Pinheiro, Mario J.
2008-01-01
It is shown that the vector potential created by a charged particle in motion acts as an ideal space flow that surrounds the particle. The interaction between the particle and the entrained space flow gives rise to the observed properties of inertia and the relativistic increase of mass. Parallels are made between the inertia property of matter, electromagnetism and the hydrodynamic drag in potential flow. Accordingly, in this framework the non resistance of a particle in uniform motion through an ideal fluid (Paradox of Dirichlet) corresponds to Newton's first law. The law of inertia suggests that the physical vacuum can be modeled as an ideal fluid. It is shown that the force exerted on a particle by an ideal fluid produces two effects: i) resistance to acceleration and, ii) an increase of mass with velocity which is due to the fluid dragged by the particle, where the bare mass of the particle at rest changes when in motion ("dressed" particle). From this theoretical ground, the inertia property of matter appears in a new light representing a promising avenue to create new propulsion concepts.
Exponential beams of electromagnetic radiation
NASA Astrophysics Data System (ADS)
Bialynicki-Birula, Iwo; Bialynicka-Birula, Zofia
2006-08-01
We show that in addition to well-known Bessel, Hermitte-Gauss and Laguerre-Gauss beams of electromagnetic radiation, one may also construct exponential beams. These beams are characterized by a fall-off in the transverse direction described by an exponential function of ?. Exponential beams, like Bessel beams, carry definite angular momentum and are periodic along the direction of propagation, but unlike Bessel beams they have a finite energy per unit beam length. The analysis of these beams is greatly simplified by an extensive use of the Riemann-Silberstein vector and the Whittaker representation of the solutions of the Maxwell equations in terms of just one complex function. The connection between the Bessel beams and the exponential beams is made explicit by constructing the exponential beams as wave packets of Bessel beams. We dedicate this paper to the memory of Edwin Power who recognized in his book [1] the power of Riemann-Silberstein vector although he has not been aware of its early history.
Electromagnetic absorption in anisotropic superconductors
Hirschfeld, P.J. ); Wolfle, P.; Sauls, J.A.; Einzel, D.; Putikka, W.O.
1989-10-01
We calculate the absorptive part of the frequency-dependent conductivity for a large class of anisotropic superconductors. The effect of nonmagnetic impurity scattering is included at the level of a self-consistent {ital t}-matrix approximation. It is found that low-frequency absorption (0{lt}{Omega}{lt}2{Delta}) takes place for any superconducting state with nodes of the energy gap on the Fermi surface. We demonstrate that the limiting low-frequency dependence of {sigma}({Omega}) on impurity concentrations can help to determine the structure of the order parameter in candidate systems such as heavy-electron compounds or high-{ital T}{sub {ital c}} superconductors. We also discuss how strong scattering, similar to that observed in ordinary superconductors doped with Kondo impurities, may lead to absorption with a threshold of {Omega}{approx equal}{Delta} rather than 2{Delta} as in quasiisotropic systems. Finally, we consider the contribution of order-parameter collective modes to the electromagnetic absorption, and show that this absorption may be substantial and depends sensitively on the impurity scattering rate.
Impedance effects on electromagnetic susceptibility
NASA Astrophysics Data System (ADS)
Ng, W. C.; King, R. J.
1987-06-01
This report studies the impedance effects on electromagnetic susceptibility for various loading conditions. From measurements of the self-impedance (Z sub A) and received voltage across 50 ohms at the terminals of a generic test object, a Thevenin equivalent circuit model is derived. Then, using this model, the load voltage, current, spectral energy density and accumulated energy are computed for several interesting load impedances. Of interest are two worst cases where the load impedance is the complex conjugate of Z sub A and the conjugate pure reactance of Z sub A. Another case of particular interest is where the load impedance is that of an electronic unit representing that of a typical subsystem designed for operation at much lower frequencies. These three cases are compared with the voltage, current and energy at a 50 ohm load. It is concluded that the load voltage, current, spectral energy density and accumulated energy of the two conjugate cases can be one or two orders of magnitude larger than that for the 50 ohm case as might be expected. However, load voltage, current, and spectral energy density at the input of the electronic units tested are comparable to that of the 50 ohm case. The spectral energy density responses are generally within a factor of two (+/- 3 dB), but may be as large as a factor of three (+/- 5 dB) over narrow frequency bands.
Electromagnetic Nature of Nuclear Energy
NASA Astrophysics Data System (ADS)
Schaeffer, Bernard
2014-09-01
As it is known since two millenaries, there is an attraction between an electric charge and a neutral object. Coulomb found the fundamental laws of electricity two centuries ago. After one century of nuclear physics, the fundamental laws of the strong force are still ignored. It has been found that electric and magnetic Coulomb's laws alone, without any hypothetical centrifugal force, are able to predict the binding energy of the simplest bound nucleus, the deuteron 2 H with a precision of 4 % . The nuclear potential is given by the formula: Uem2 H / A =e2/4 ??0 (1/rnp + a - 1/rnp - a ) + ?0 |?n?p |/4 ? rnp3. This potential shows a horizontal inflection point where the electric and magnetic forces are equilibrated, coinciding with the experimental deuteron binding energy. Similar results have been obtained for the ? particle 4 He where the electric attractive potential is four times larger than that of 2 H while the magnetic repulsion is only 1 . 5 times larger and the 4 HE binding energy six times larger than that of the deuteron. These results, prove the electromagnetic nature of the nuclear energy without the usual assumptions.
Electromagnetic radiation from microwave ovens.
Alhekail, Z O
2001-09-01
Electromagnetic radiation from microwave ovens in Saudi Arabia was investigated by means of a field measurement survey. The survey was carried out for 106 ovens used in households and restaurants in Riyadh city. Ovens were between 1 month and 14 years old with operating power ranging from 0.5 to 4.4 kW. One oven was found to leak more than the 5 mW cm(-2) limit specified in the standard. Fifteen other ovens were found to leak 1 mW cm(-2) or more, with the remaining ovens leaking less than that. Based on the survey result, previous studies and the fast decay of radiated power density with distance from the oven, the conclusion was that user exposure to RF radiation from microwave ovens is much less than the general public exposure limit set by most international standards at 2450 MHz, i.e. 1 mW cm(-2), and that a detrimental effect on health is an unlikely result of exposure to radiation from microwave ovens. PMID:11594651
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.
Dual-supply electromagnetic pumps. Mathematical model
Bocheninskii, V.P.; Drits, M.S.; Zvane, G.Ya.; Ivanov, S.L.; Lielpeter, Ya.Ya.; Pukis, M.V.; Stukalov, P.M.; Tananaev, A.V.; Ushakov, Yu.P.; Shmarov, V.S.
1988-07-01
A mathematical model illustrating the main properties of dual-supply electromagnetic pumps are proposed. The model neglects edge effects and the structure of the flow. On the basis of the model, investigations of the operating regimes along with a preliminary evaluation of possible areas of use are carried out, and problems of investigating dual-supply electromagnetic pumps are also raised. Limiting cases of the model are given and the problems posed by modeling edge effects and internal hydraulics are discussed.
Viscoelastic-electromagnetism and Hall viscosity
NASA Astrophysics Data System (ADS)
Hidaka, Yoshimasa; Hirono, Yuji; Kimura, Taro; Minami, Yuki
2013-01-01
We introduce a kind of electromagnetism, which we call viscoelastic-electromagnetism, to investigate viscoelastic transport phenomena. It is shown that Cartan's formalism of general relativity is essential for viscoelastic theory, and then the corresponding electric and magnetic fields are regarded as a velocity gradient and a Burgers vector density, respectively. As an application of this formalism, the St\\check {{r}}eda formula for the Hall viscosity is presented.
Numerical Electromagnetic Field Analysis for EMC Problems
Heinz-Dietrich Bruns; Christian Schuster; Hermann Singer
2007-01-01
Much progress has been made in the use of computational electromagnetics for the analysis of electromagnetic compatibility (EMC) problems during recent years. This paper reviews the improvements in some of the most important techniques of the field: the method of moments, the finite-difference time-domain method, the finite-element method, the transmission-line matrix method, and the partial-element equivalent-circuit method. The results of
Channel shape optimization of electromagnetic pumps
Leboucher, L.; Boissonneau, P. [LEGI, Genoble (France). Inst. de Mecanique de Grenoble] [LEGI, Genoble (France). Inst. de Mecanique de Grenoble; Villani, D. [Framatome direction Novatome, Lyon (France)] [Framatome direction Novatome, Lyon (France)
1995-05-01
Electromagnetic pumps are used for the transportation of liquid metals such as the cooling sodium of fast breeder nuclear reactors. The design of this induction machine is close to that of a tubular linear induction motor. In this paper, channels of variable cross section are used to improve the efficiency of electromagnetic pumps. The optimum channel shape is derived analytically and is then tested with a finite element code. The performances are compared with those of standard pumps.
Slot design of optimized electromagnetic pump
Leboucher, L. (LEGI, Grenoble (France). Institut de Mecanique); Villani, D. (Framatome direction Novatome, Lyon (France))
1993-11-01
Electromagnetic pumps are used for the transportation of liquid metals such as the cooling sodium of fast breeder nuclear reactors. The design of this induction machine is close to that of a tubular linear induction motor. A non uniform slot distribution is used to optimize electromagnetic pumps. This geometry is tested with a finite element code. The performances are compared with the regular slot distribution of Industrial prototypes.
Bioelectromagnetic effects of the electromagnetic pulse (EMP)
E. L. Patrick; W. L. Vault
1990-01-01
The public has expressed concern about the biological effects and hazards of non-ionizing electromagnetic fields produced by the electro-magnetic pulse (EMP) simulators that simulate the EMP emanating from a high-altitude nuclear explosion. This paper provides a summary of the bioelectromagnetic effects literature up through the present, describes current occupational standards for workers exposed to the EMP environment, and discusses the
High-Power Electromagnetic Thruster Being Developed
NASA Technical Reports Server (NTRS)
LaPointe, Michael R.; Mikellides, Pavlos G.
2001-01-01
High-power electromagnetic thrusters have been proposed as primary in-space propulsion options for several bold new interplanetary and deep-space missions. As the lead center for electric propulsion, the NASA Glenn Research Center designs, develops, and tests high-power electromagnetic technologies to meet these demanding mission requirements. Two high-power thruster concepts currently under investigation by Glenn are the magnetoplasmadynamic (MPD) thruster and the Pulsed Inductive Thruster (PIT).
Some theorems in gravitational and electromagnetic fields
Zihua Weng
2009-06-12
The paper discusses the influences of velocity curl and field strength on some theorems in the electromagnetic field and gravitational field. With the characteristics of the algebra of quaternions, the theorem of linear momentum, conservation of linear momentum, and conservation of angular momentum etc. can be deduced from the quaternionic definitions of physical quantities. And the strength of gravitational field and electromagnetic field have an influence on some theorems directly. While the velocity curl has an effect on some theorems also.
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.
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.
Geometric phases in multidirectional electromagnetic coupling theory
NASA Astrophysics Data System (ADS)
L?nares, J.; Nistal, M. C.
1992-01-01
Geometric phases are determined for N coupled electromagnetic wave amplitudes evolving in their projective Hilbert space. Multidirectional coupling systems subject to SU ( N) dynamical symmetry are proposed and Aharonov-Anandan phases are evaluated in a spinorial representation, for both closed and partial circuits described by the SU(2) group. Following closely Bhandari's idea, this kind of systems enlarges the general framework of topological phases for electromagnetic waves.
Electromagnetic Transport from Microtearing Mode Turbulence
Guttenfelder, W.; Kaye, S. M.; Bell, R. E.; Hammett, G. W.; LeBlanc, B. P.; Mikkelsen, D. R. [Princeton Plasma Physics Laboratory, Princeton New Jersey 08543 (United States); Candy, J. [General Atomics, San Diego, California 92186 (United States); Nevins, W. M.; Wang, E. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Yuh, H. [Nova Photonics Inc., Princeton, New Jersey 08540 (United States)
2011-04-15
This Letter presents nonlinear gyrokinetic simulations of microtearing mode turbulence. The simulations include collisional and electromagnetic effects and use experimental parameters from a high-{beta} discharge in the National Spherical Torus Experiment. The predicted electron thermal transport is comparable to that given by experimental analysis, and it is dominated by the electromagnetic contribution of electrons free-streaming along the resulting stochastic magnetic field line trajectories. Experimental values of flow shear can significantly reduce the predicted transport.
2010-01-01
; 78A45; 78A48; Key words: electromagnetic waves; wave scattering by many small bodies; smart materials. 2 #12;1 Introduction In this paper we outline a theory of electromagnetic (EM) wave scatteringProgress in Electromagnetic Research, M (PIER M), 14, (2010),193-206. 1 #12;Electromagnetic wave
2010-01-01
: electromagnetic waves; wave scattering by many small bodies; smart materials. 1 Introduction It is known (see, e small particles Electromagnetic (EM) wave scattering problem consists of finding vectors E and HProgress in Electromagnetic Research Letters, 19, (2010), 147-154. 1 #12;Electromagnetic wave
ALICE electromagnetic calorimeter prototype test
Awes, Terry; /Oak Ridge
2005-09-01
This Memorandum of Understanding between the Test Beam collaborators and Fermilab is for the use of beam time at Fermilab during the Fall, 2005 Meson Test Beam Run. The experimenters plan to measure the energy, position, and time resolution of prototype modules of a large electromagnetic calorimeter proposed to be installed in the ALICE experiment at the LHC. The ALICE experiment is one of the three large approved LHC experiments, with ALICE placing special emphasis on the LHC heavy-ion program. The large electromagnetic calorimeter (EMCal) is a US initiative that is endorsed by the ALICE collaboration and is currently in the early stages of review by the Nuclear Physics Division of the DOE. The installation in the test beam at FNAL and test beam measurements will be carried out by the US members of the ALICE collaboration (ALICE-USA). The overall design of the ALICE EMCal is heavily influenced by its location within the ALICE L3 magnet. The EMCal is to be located inside the large room temperature magnet within a cylindrical integration volume approximately l12cm deep, by 5.6m in length, sandwiched between the ALICE TPC space frame and the L3 magnet coils. The chosen technology is a layered Pb-scintillator sampling calorimeter with a longitudinal pitch of 1.6mm Pb and 1.6mm scintillator. The full detector spans {eta} = -0.7 to {eta} = 0.7 with an azimuthal acceptance of {Delta}{phi} = 120{sup o}. The EMCal readout is of a ''Shish-Kabob'' type similar to the PHENIX Pb-scintillator sampling calorimeter in which the scintillation light is collected via wavelength shifting fibers running through the Pb-scintillator tiles perpendicular to the front surface. The detector is segmented into {approx}14000 towers. The basic structural units of the calorimeter are supermodules, each subtending approximately {approx}20{sup o} in {Delta}{phi} and 0.7 units in {Delta}{eta}. Supermodules are assembled from individual modules. The modules are further segmented into 2 x 2 individually read out towers. The fibers from an individual tower are grouped together to form readout tower bundles. These are each optically coupled to an avalanche photodiode (APO) via a short light guide to provide some spatial optical mixing and to match the fiber bundle to the APO. The module assembly is indicated in Figure l. The supermodules weigh about 9.6 tons and are the basic units handled during installation. Each supermodule is roughly I45cm wide at the front surface by 350cm long with an active depth of 24.5cm (at {eta} = 0) plus an additional 6.6 cm of depth in structural plates. The physical characteristics of the ALICE EMCal are summarized in Table 1. The EMCal test beam measurements at FNAL will utilize a stacked 4 x 4 array of prototype EMCal modules (8 x 8 towers). All towers will be instrumented with the same model APO and preamplifier as will be used in the ALICE experiment and all channels will be readout with existing prototype front end electronics intended for use in ALICE. The goals of the test beam measurements are: To investigate the energy resolution, linearity, uniformity, and position resolution, using electron beams; To study the energy dependence of the response to electrons and hadrons to determine the particle identification capabilities of the EMCal by shower shape; And to investigate the timing characteristics of the energy signal for crude time-of-flight measurement ({approx} 1ns) for use for anti-neutron rejection. Measurements will be made for comparison with different signal shaping times in the front end electronics.
Mapping permafrost with airborne electromagnetics
NASA Astrophysics Data System (ADS)
Minsley, B. J.; Ball, L. B.; Bloss, B. R.; Kass, A.; Pastick, N.; Smith, B. D.; Voss, C. I.; Walsh, D. O.; Walvoord, M. A.; Wylie, B. K.
2014-12-01
Permafrost is a key characteristic of cold region landscapes, yet detailed assessments of how the subsurface distribution of permafrost impacts the environment, hydrologic systems, and infrastructure are lacking. Data acquired from several airborne electromagnetic (AEM) surveys in Alaska provide significant new insight into the spatial extent of permafrost over larger areas (hundreds to thousands of square kilometers) than can be mapped using ground-based geophysical methods or through drilling. We compare several AEM datasets from different areas of interior Alaska, and explore the capacity of these data to infer geologic structure, permafrost extent, and related hydrologic processes. We also assess the impact of fires on permafrost by comparing data from different burn years within similar geological environments. Ultimately, interpretations rely on understanding the relationship between electrical resistivity measured by AEM surveys and the physical properties of interest such as geology, permafrost, and unfrozen water content in the subsurface. These relationships are often ambiguous and non-unique, so additional information is useful for reducing uncertainty. Shallow (upper ~1m) permafrost and soil characteristics identified from remotely sensed imagery and field observations help to constrain and aerially extend near-surface AEM interpretations, where correlations between the AEM and remote sensing data are identified using empirical multivariate analyses. Surface nuclear magnetic resonance (sNMR) measurements quantify the contribution of unfrozen water at depth to the AEM-derived electrical resistivity models at several locations within one survey area. AEM surveys fill a critical data gap in the subsurface characterization of permafrost environments and will be valuable in future mapping and monitoring programs in cold regions.
Is Electromagnetic Gravity Control Possible?
Vargas, Jose G. [PST Associates, 600 Westover Rd, Columbia, SC 29210 (United States); Torr, Douglas G. [PST Associates, 5221 Tern Place, Fayetteville, NC 28311-1967 (United States)
2004-02-04
We study the interplay of Einstein's Gravitation (GR) and Maxwell's Electromagnetism, where the distribution of energy-momentum is not presently known (The Feynman Lectures, Vol 2, Chapter 27, section 4). As Feynman himself stated, one might in principle use Einstein's equations of GR to find such a distribution. GR (born in 1915) presently uses the Levi-Civita connection, LCC (the LCC was born two years after GR as a new concept, and not just as the pre-existing Christoffel symbols that represent it). Around 1927, Einstein proposed for physics an alternative to the LCC that constitutes a far more sensible and powerful affine enrichment of metric Riemannian geometry. It is called teleparallelism (TP). Its Finslerian version (i.e. in the space-time-velocity arena) permits an unequivocal identification of the EM field as a geometric quantity. This in turn permits one to identify a completely geometric set of Einstein equations from curvature equations. From their right hand side, one may obtain the actual distribution of EM energy-momentum. It is consistent with Maxwell's equations, since these also are implied by the equations of structure of TP. We find that the so-far-unknown terms in this distribution amount to a total differential and do not, therefore, alter the value of the total EM energy-momentum. And yet these extra terms are at macroscopic distances enormously larger than the standard quadratic terms. This allows for the generation of measurable gravitational fields by EM fields. We thus answer affirmatively the question of the title.
[Health effects of electromagnetic fields].
Röösli, Martin
2013-12-01
Use of electricity causes extremely low frequency magnetic fields (ELF-MF) and wireless communication devices emit radiofrequency electromagnetic fields (RF-EMF). Average ELF-MF exposure is mainly determined by high voltage power lines and transformers at home or at the workplace, whereas RF-EMF exposure is mainly caused by devices operating close to the body (mainly mobile and cordless phones). Health effects of EMF are controversially discussed. The IARC classified ELF-MF and RF-EMF as possible carcinogenic. Most consistent epidemiological evidence was found for an association between ELF-MF and childhood leukaemia. If causal, 1 - 4 percent of all childhood leukaemia cases could be attributed to ELF-MF. Epidemiological research provided some indications for an association between ELF-MF and Alzheimer's diseases as well as amyotrophic lateral sclerosis, although not entirely consistent. Regarding mobile phones and brain tumours, some studies observed an increased risk after heavy or long term use on the one hand. On the other hand, brain tumour incidence was not found to have increased in the last decade in Sweden, England or the US. Acute effects of RF-EMF on non-specific symptoms of ill health seem unlikely according to randomized and double blind provocation studies. However, epidemiological research on long term effects is still limited. Although from the current state of the scientific knowledge a large individual health risk from RF-EMF exposure is unlikely, even a small risk would have substantial public health relevance because of the widespread use of wireless communication technologies. PMID:24297859
Ji-Ge ZHANG; Hui-Jie YIAN; Yuan-Qiang WU; Xin-Xin WU; Su-Yuan YU; Shu-Yan HE
2007-01-01
The movable coil electromagnet drive mechanism (MCEDM) is a new drive scheme for the reactor control rod, and it has a simple structure, good security and reliability property, etc. MCEDM with an air cooled structure has been used in the land research reactor. In order to apply MCEDM to the mobile reactor, experimental and theoretical study on the electromagnet with
Electromagnetic navigation in lung cancer: research update.
Eberhardt, Ralf; Gompelmann, Daniela; Herth, Felix Jf
2009-10-01
Unfortunately, flexible bronchoscopy, the least invasive bronchoscopic procedure, is of limited value for obtaining tissue from lesions in the peripheral segments of the lung. Biopsy success is further compromised if the lesion is less than 3 cm in diameter. The main limitation of flexible bronchoscopy is the difficulty in reaching peripheral lesions with the accessory tools. In this paper, we will discuss a new bronchoscopic advance in the diagnosis and treatment of lung cancer. Once extended beyond the tip of the bronchoscope, these tools are difficult to guide to the desired location. Localizing the lesion under fluoroscopy is difficult, and alternative diagnostic guidance methods, such as computer tomography-guided bronchoscopy and endobronchial ultrasound, are more demanding. Therefore, new methods for navigation and localization are needed. One of these new technologies is electromagnetic navigation bronchoscopy. The aim of this special report is to provide an analysis of the published literature. A literature search was constructed and performed on PubMed to identify the literature from 2000 to 2008. The search words were 'electromagnetic navigation', 'coin lesion', 'solitary pulmonary nodule' and 'lung cancer'. We review a number of recent studies that utilize electromagnetic navigation and guidance, and analyze their performance characteristics for clinical applications of the technology. Electromagnetic navigation is likely to play an increasing and integral role in the diagnosis and staging of lung cancer in the near future. Electromagnetic registration may impact both the staging and diagnosis of peripheral lesions. PMID:20477337
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.
Power law inflation with electromagnetism
Luo, Xianghui; Isenberg, James, E-mail: isenberg@uoregon.edu
2013-07-15
We generalize Ringström’s global future causal stability results (Ringström 2009) [11] for certain expanding cosmological solutions of the Einstein-scalar field equations to solutions of the Einstein–Maxwell-scalar field system. In particular, after noting that the power law inflationary spacetimes (M{sup n+1},g{sup -hat}, ?{sup -hat}) considered by Ringström (2009) in [11] are solutions of the Einstein–Maxwell-scalar field system (with exponential potential) as well as of the Einstein-scalar field system (with the same exponential potential), we consider (nonlinear) perturbations of initial data sets of these spacetimes which include electromagnetic perturbations as well as gravitational and scalar perturbations. We show that if (as in Ringström (2009) [11]) we focus on pairs of relatively scaled open sets U{sub R{sub 0}}?U{sub 4R{sub 0}} on an initial slice of (M{sup n+1},g{sup -hat}), and if we choose a set of perturbed data which on U{sub 4R{sub 0}} is sufficiently close to that of (M{sup n+1},g{sup -hat},?{sup -hat}, A{sup -hat} = 0), then in the maximal globally hyperbolic spacetime development (M{sup n+1},g,?,A) of this data via the Einstein–Maxwell-scalar field equations, all causal geodesics emanating from U{sub R{sub 0}} are future complete (just as in (M{sup n+1},g{sup -hat})). We also verify that, in a certain sense, the future asymptotic behavior of the fields in the spacetime developments of the perturbed data sets does not differ significantly from the future asymptotic behavior of (M{sup n+1},g{sup -hat}, ?{sup -hat}, A{sup -hat} = 0). -- Highlights: •We prove stability of expanding solutions of the Einstein–Maxwell-scalar field equations. •All nearby solutions are geodesically complete. •The topology of the initial slice is irrelevant to our stability results.
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.
Electromagnetic wave absorption characteristics of multiwalled carbon nanocoils
NASA Astrophysics Data System (ADS)
Eguchi, Usaburo; Takikawa, Hirofumi; Suda, Yoshiyuki
2014-04-01
We have studied the electromagnetic wave absorption properties of a multiwalled carbon nanocoil (MWCNC), a promising lightweight and wide-band electromagnetic wave absorber. Experiments were conducted using several types of paste with various weight concentrations of MWCNC compounded into an organic binder. The results revealed the significant electromagnetic wave absorption potential of the MWCNC. They also verified that its electromagnetic wave absorption effect is strongly dependent on MWCNC concentration, so that there is an optimal MWCNC composition. The increased sample thickness enhances electric conduction loss and encourages electromagnetic wave absorption, even in a high-frequency range. Consequently, the MWCNC has been demonstrated as a new outstanding electromagnetic wave absorber.
Electromagnetic Processing of Materials:. from the Concepts to Industrial Applications
NASA Astrophysics Data System (ADS)
Delannoy, Y.
2005-07-01
Electromagnetic fields are used for material processing in various industrial devices, such as induction furnaces, electromagnetic brakes and stirrers in metallurgy, inductive plasma torches to elaborate silica for optical fibres or electromagnetic flow control systems in crystal growth. New developments are needed whenever the coupling of physical phenomena is the key point of the process. Three examples are presented among the research activities of the EPM laboratory in Electromagnetic Processing of Materials: Electromagnetic continuous casting of steel slabs, plasma purification of silicon, electromagnetic stirring of solidifying alloys. Some scientific open questions important for such processes are presented.
Electromagnetic Counterparts of Gravitational Wave Transients
NASA Astrophysics Data System (ADS)
Branchesi, Marica
2015-03-01
In the near future the ground-based gravitational wave detectors will reach sensitivities that should make it possible for the first time to directly observe gravitational waves. The simultaneous availability of gravitational wave detectors observing together with space and ground-based electromagnetic telescopes will offer a great opportunity to explore the Universe in a new multi-messenger perspective. Promising sources of gravitational waves are the most energetic astrophysical events such as the merger of neutron stars and/or stellar-mass black holes and the core collapse of massive stars. These events are believed to produce electromagnetic transients in the sky, like gamma-ray bursts and supernovae. An overview of the expected electromagnetic counterparts of the gravitational wave sources is presented, focusing on the challenges, opportunities and strategies for starting transient gravitational wave astronomy.
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.
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).
Advanced electromagnetic methods for aerospace vehicles
NASA Astrophysics Data System (ADS)
Balanis, Constantine A.; Sun, Weimin; El-Sharawy, El-Budawy; Aberle, James T.; Birtcher, Craig R.; Peng, Jian; Tirkas, Panayiotis A.
1992-06-01
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.
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.
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.
Tracing buried pipelines using multi frequency electromagnetic
NASA Astrophysics Data System (ADS)
El-Qady, Gad; Metwaly, Mohamed; Khozaym, Ashraf
2014-06-01
In this paper the application of multi frequency electromagnetic techniques to locate buried pipelines is described. The survey site has two pipelines of SUMED, one of the world chokepoints. At desert or arid areas, regular geophysical surveys usually are difficult to carry out. EM techniques could be the best among geophysical techniques to be used for this target at these conditions. The EM survey was performed using a GEM-300 multi-frequency electromagnetic profiler. It is of handheld electromagnetic induction-type that measures in-phase and quadrature terrain conductivity without electrodes or direct soil contact. An area of 60 × 15 m was surveyed, that supposed SUMED pipeline existed. Six different frequencies, typically 2025, 2875, 4125, 5875, 8425, 12,025 Hz, have been used simultaneously. The slice maps for in-phase and conductivity distribution at each frequency could help to trace the extension of the pipeline. Two pipelines were traced successfully with 20 m spacing of each others.
Charged particle acceleration by intermittent electromagnetic turbulence
NASA Astrophysics Data System (ADS)
Zelenyi, L. M.; Rybalko, S. D.; Artemyev, A. V.; Petrukovich, A. A.; Zimbardo, G.
2011-09-01
We studied the role of intermittency in the process of acceleration and transport of charged particles by electromagnetic turbulence. We propose a simple model of electromagnetic turbulence with a variable level of intermittency. The magnetic field is described as a superposition of an ensemble of magnetostatic plane waves and of spatially localized dynamic magnetic clouds. The amplitudes of magnetic clouds are distributed according to an intermittent map. The model approximates essential properties of turbulence observed ‘in situ’ in the neutral plane of the Earth's magnetotail. Numerical integration of charged particle trajectories in such a dynamic electromagnetic environment shows that, for the fixed time interval, the higher the level of intermittency, the higher the energy gain. Moreover, in a sufficiently intermittent turbulence, particle acceleration occurs without significant intensification of the spatial transport.
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.
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.
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.
Perfectly reflectionless omnidirectional absorbers and electromagnetic horizons
NASA Astrophysics Data System (ADS)
Sainath, Kamalesh; Teixeira, Fernando L.
2015-08-01
We demonstrate the existence of metamaterial blueprints describing, and fundamental limitations concerning, perfectly reflectionless omnidirectional electromagnetic absorbers (PR-OEMA). Previous attempts to define PR-OEMA blueprints have led to active (gain), rather than passive, media. We explain this fact and unveil new, distinct limitations of true PR-OEMA devices, including the appearance of an "electromagnetic horizon" on physical solutions. As practical alternatives we introduce alternative OEMA blueprints corresponding to media that, while not reflectionless, are nonetheless effective in absorbing incident waves in a manner robust to incident wave diversity.
Axial electromagnetic force density in MPD thrusters
Sheshadri, T.S. (Dept. of Aerospace Engineering, Indian Inst. of Science, Bangalore 560 012 (India))
1992-10-10
In this paper an MPD thruster formulation involving coupled aerothermodynamic-electromagnetic equations and including viscous effects is developed and solved. The electromagnetic force density distribution in the thruster interior is studied. Axial force densities are fount to be largest on the cathode longitudinal surface. Very large force densities are found at the cathode upstream end and this is attributed to large values of the Hall parameter. Over the rest of the cathode longitudinal surface, axial force densities increase with increasing inlet velocities and mass densities and large plasma viscosities. Equivalent increases in inlet velocity and mass density produce effects of different magnitudes.
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.
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.
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.
Enhanced electromagnetic emission from a dusty plasma
NASA Astrophysics Data System (ADS)
Shukla, P. K.; Stenflo, L.; Resendes, D. P.
2002-03-01
It is shown how enhanced electromagnetic emission (EEE) is induced when large amplitude electromagnetic waves scatter off acoustic-like modes in a dusty plasma. Following the formalism of standard parametric interactions and using the Rostoker superposition principle, a general expression for the ensemble average of the square of the vector potential of EEE is derived. The result should be useful in deducing the plasma parameters in-situ when intense radar beams are used for the diagnosis of the polar mesospheric summer echos in association with low-frequency irregularities.
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.
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
Bioelectromagnetic effects of the electromagnetic pulse (EMP)
Patrick, E.L.; Vault, W.L.
1990-03-01
The public has expressed concern about the biological effects and hazards of non-ionizing electromagnetic fields produced by the electro-magnetic pulse (EMP) simulators that simulate the EMP emanating from a high-altitude nuclear explosion. This paper provides a summary of the bioelectromagnetic effects literature up through the present, describes current occupational standards for workers exposed to the EMP environment, and discusses the use of medical surveillance as it relates to the potential human health hazards associated with exposure to the EMP environment.
Feedback controlled electrostatic and electromagnetic sample positioners
NASA Technical Reports Server (NTRS)
Rhim, Won-Kyu; Elleman, D. D.
1990-01-01
Four different sample positioners are discussed. The four systems share a common operating principle in that the sample positioning is achieved by feedback controlled forces which can be electrostatic, dielectrophoretic, or electromagnetic. The first system is the electrostatic liquid drop positioner which operates at the near ambient position. The second system is the tetrahedral electrostatic positioner which is being developed for the high temperature materials processing in vacuum. The third system is essentially the the same tetrahedral system above except that the position control is achieved by dielectrophoretic forces in the pressurized gas environment. Finally, the feasibility of a feedback controlled electromagnetic positioner is discussed.
Electromagnetic imaging through thick metallic enclosures
NASA Astrophysics Data System (ADS)
Darrer, Brendan J.; Watson, Joseph C.; Bartlett, Paul A.; Renzoni, Ferruccio
2015-08-01
The ability to image through metallic enclosures is an important goal of any scanning technology for security applications. Previous work demonstrated the penetrating power of electromagnetic imaging through thin metallic enclosures, thus validating the technique for security applications such as cargo screening. In this work we study the limits of electromagnetic imaging through metallic enclosures, considering the performance of the imaging for different thicknesses of the enclosure. Our results show, that our system can image a Copper disk, even when enclosed within a 20 mm thick Aluminum box. The potential for imaging through enclosures of other materials, such as Lead, Copper, and Iron, is discussed.
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.
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.
Program For Displaying Computed Electromagnetic Fields
NASA Technical Reports Server (NTRS)
Hom, Kam W.
1995-01-01
EM-ANIMATE computer program specialized visualization displays and animates output data on near fields and surface currents computed by electromagnetic-field program - in particular MOM3D (LAR-15074). Program based on windows and contains user-friendly, graphical interface for setting viewing options, selecting cases, manipulating files, and like. Written in FORTRAN 77. EM-ANIMATE also available as part of package, COS-10048, includes MOM3D, IRIS program computing near-field and surface-current solutions of electromagnetic-field equations.
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.
Forces in electromagnetic field and gravitational field
Zihua Weng
2011-03-31
The force can be defined from the linear momentum in the gravitational field and electromagnetic field. But this definition can not cover the gradient of energy. In the paper, the force will be defined from the energy and torque in a new way, which involves the gravitational force, electromagnetic force, inertial force, gradient of energy, and some other new force terms etc. One of these new force terms can be used to explain why the solar wind varies velocity along the magnetic force line in the interplanetary space between the sun and the earth.
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.
Open questions in quarkonium and electromagnetic probes
Carlos Lourenco
2006-12-09
In my ("not a summary") talk at the Hard Probes 2006 conference, I gave "a personal and surely biased view on only a few of the many open questions on quarkonium and electromagnetic probes". Some of the points reported in that talk are exposed in this paper, having in mind the most important of all the open questions: do we have, today, from experimental data on electromagnetic probes and quarkonium production, convincing evidence that shows, beyond reasonable doubt, the existence of "new physics" in high-energy heavy-ion collisions?
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.
Electromagnetic Interference in Wireless Communications: Behavioral-Level Simulation
Loyka, Sergey
Electromagnetic Interference in Wireless Communications: Behavioral-Level Simulation Approach in electromagnetic interference (EMI) modeling and simulation for modern and future wireless communication systems as well. Keywords- nonlinear effects, behavioral-level simulation, wireless communications I. INTRODUCTION
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) ...
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.
Electromagnetically induced transparency with broadband laser pulses D. D. Yavuz
Yavuz, Deniz
Electromagnetically induced transparency with broadband laser pulses D. D. Yavuz Department pulses inside an atomic medium using electromag- netically induced transparency. Extending the suggestion.65. k Over the last decade, counterintuitive optical effects using electromagnetically induced
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...
Occupational Electric Shocks, Electromagnetic Fields and Amyotrophic Lateral Sclerosis
Vergara, Ximena Patricia
2012-01-01
ABSTRACT OF THE DISSERTATION Occupational Electric Shocks, Electromagnetic Fields and Amyotrophic Lateral SclerosisAbstract ii Acknowledgements ix Vita xi 1. Occupational Electric Shocks, Electromagnetic Fields and Amyotrophic Lateral Sclerosis
611: Electromagnetic Theory II Special relativity; Lorentz covariance of Maxwell equations
Pope, Christopher
611: Electromagnetic Theory II CONTENTS #15; Special relativity; Lorentz covariance of Maxwell particles #15; Action principle for electromagnetism; energy-momentum tensor #15; Electromagnetic waves Electromagnetic Fields 38 3.1 Description in terms of potentials
611: Electromagnetic Theory II . Special relativity; Lorentz covariance of Maxwell equations
Pope, Christopher
611: Electromagnetic Theory II CONTENTS . Special relativity; Lorentz covariance of Maxwell . Action principle for electromagnetism; energymomentum tensor . Electromagnetic waves; waveguides Electromagnetic Fields 42 3.1 Description in terms of potentials
611: Electromagnetic Theory II Special relativity; Lorentz covariance of Maxwell equations
Pope, Christopher
611: Electromagnetic Theory II CONTENTS · Special relativity; Lorentz covariance of Maxwell · Action principle for electromagnetism; energy-momentum tensor · Electromagnetic waves; waveguides Electromagnetic Fields 42 3.1 Description in terms of potentials
Myung, Noh-Hoon
Journal of Electromagnetic Waves and Applications, Vol. 14, 991- 942, 2000 , OBLIQUE SCATTERING basic problems in electromagnetic compatibility (EMC). When an electromagnetic interference (EMI) signal the availablepublished data. 1. INTRODUCTION Electromagnetic penetration through and scattering from apertures are two
Neutrino electromagnetic interactions: A window to new physics
NASA Astrophysics Data System (ADS)
Giunti, Carlo; Studenikin, Alexander
2015-04-01
A review is given of the theory and phenomenology of neutrino electromagnetic interactions, which provide powerful tools to probe the physics beyond the standard model. After a derivation of the general structure of the electromagnetic interactions of Dirac and Majorana neutrinos in the one-photon approximation, the effects of neutrino electromagnetic interactions in terrestrial experiments and in astrophysical environments are discussed. The experimental bounds on neutrino electromagnetic properties are presented and the predictions of theories beyond the standard model are confronted.
UNIVERSITY OF CALIFORNIA, Macroscopic Electromagnetic Properties of the
Heidbrink, William W.
UNIVERSITY OF CALIFORNIA, IRVINE Macroscopic Electromagnetic Properties of the Irvine Field ..................................................................................................................................39 4.5 ROGOWSKI COIL
Capsule pipeline transport using an electromagnetic drive
Bruce Montgomery; S. Fairfax; Bradford Smith
2001-01-01
Development of our electromagnetic capsule pipeline system was initiated by the desire of the Florida Phosphate Industry to find a cost effective way to reduce the environmental impact of conventional transportation of their very large quantities of material. Typical ore applications would use an underground pair of 610 mm diameter pipes for outbound and returning capsules, and would typically carry
Standardized evaluation method for electromagnetic tracking systems
Johann Hummel; Calvin Maurer Jr.; Michael Figl; Michael Bax; Helmar Bergmann; Wolfgang Birkfellner; Ramin Shahidi
2005-01-01
The major aim of this work was to define a protocol for evaluation of electromagnetic tracking systems (EMTS). Using this protocol we compared two commercial EMTS: the Ascension microBIRD (B) and NDI Aurora (A). To enable reproducibility and comparability of the assessments a machined base plate was designed, in which a 50 mm grid of holes is precision drilled for
Laboratory assessment of a miniature electromagnetic tracker
Johann Hummel; Wolfgang Birkfellner; Michael Figl; C. Haider; Rudolf A. Hanel; Helmar Bergmann
2002-01-01
With the invention of miniaturized electromagnetic digitizers comes a variety of potential clinical applications for computer aided interventions using flexible instruments; it has become possible to track endoscopes or catheters within the body. To evaluate the reliability of a new commercial tracking system, we measured the systematic distortions induced by various materials such as closed metallic loops, wire guides, catheters
Evaluation of dynamic electromagnetic tracking deviation
Johann Hummel; Michael Figl; Michael Bax; Ramin Shahidi; Helmar Bergmann; Wolfgang Birkfellner
2009-01-01
Electromagnetic tracking systems (EMTS's) are widely used in clinical applications. Many reports have evaluated their static behavior and errors caused by metallic objects were examined. Although there exist some publications concerning the dynamic behavior of EMTS's the measurement protocols are either difficult to reproduce with respect of the movement path or only accomplished at high technical effort. Because dynamic behavior
ABSORBING BOUNDARY CONDITIONS FOR ELECTROMAGNETIC WAVE PROPAGATION
ABSORBING BOUNDARY CONDITIONS FOR ELECTROMAGNETIC WAVE PROPAGATION Xiaobing Fengy Abstract. In this paper, the theoretical perfectly absorbing boundary condition on the boundary of a half{space domain into the interior. By approximating this theoretical boundary condition a class of local absorbing boundary
Electromagnetic scattering from cascaded strip gratings
Akira Matsushima; Tokuya Itakura
1990-01-01
An accurate numerical solution for the electromagnetic scattering from cascaded strip gratings is presented. The gratings are free-standing and must have common periodicity, but may be staggered. The propagation direction and the polarization of the incident plane wave are arbitrary. A set of singular integral equations is derived and solved by the moment method, where the Chebyshev polynomials are chosen
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.
The physics of tachyons. 3: Tachyon electromagnetism
NASA Astrophysics Data System (ADS)
Dawe, Ross L.; Hines, Kenneth C.
A new formulation of the theory of tachyons using the same two postulates as in special relativity is applied to electro- magnetism. Tachyonic transformations of the electromagnetic fields E and B are rigorously derived from Maxwell's equations and are shown to be the same as for bradyonic transformations. Tachyonic tranformations of current density, charge density, scalar and vector potentials are also derived and discussed. Tachyonic optics and the four-potential of a moving tachyonic charge are also discussed, along with generalized four-vector transformations and electromagnetic four-tensors in extended relativity. Use is made of a switching principle to show how tachyons automatically obey the law of conservation of electric charge in any inertial reference frame, even though the observed tachyon electric charge is not an invariant between observers. The electromagnetic field produced by a charged tachyon takes the form of a Mach cone, inside which the electromagnetic field is real and detectable, while outside the cone the field generated by the tachyon is imaginary and undetectable.
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…
Integrated circuit electromagnetic susceptibility investigation, phase 3
J. M. Roe; J. R. Chott; T. W. Herron; C. N. Kohlberg; C. E. Larson
1979-01-01
This report summarizes progress made in investigations into the RF susceptibility of integrated circuits (ICs). This report covers the work performed during the third of three increments. Included is a description of the revisions which were incorporated into the Integrated Circuit Electromagnetic Susceptibility Handbook (Report MDC E1929 dated 1 August 1978) which summarized all of the information obtained during the
Resonant response of electromagnetic scattering from ellipsoid
NASA Astrophysics Data System (ADS)
Gavriloaia, Mihai-Bogdan; Vizireanu, Constantin-Radu; Neamtu, Catalin; Preda, Radu; Achimescu, Emanuel; Halunga, Simona
2015-02-01
Modern radars must provide in a very short time: existence, mobility and shape of objects evolving in airspace. Evaluation of the object shapes through active research by using synthetic aperture radar is limited in time, resolution, and cost. A new way of processing non-stationary signals is presented in this article. Signals are obtained from the reflection of the electromagnetic field by objects with complex shape when they are irradiated with linear frequency modulated signals. The amplitude of reflected signal is variable on the radio-impulse duration depending on object shape, causing a certain electromagnetic signature. This phenomenon is caused by specific electromagnetic resonance. The reflected signal has maximum amplitude when the frequency of the incident wave is the same with the resonant frequency of the investigated object. The structure of an radar target can be decomposed into simple geometric shapes such as spheres, ellipsoids, prisms, and so on. Using resonant effect that ensures pattern recognition is exemplified by an object with an aerodynamic profile accepted in many component elements of the aircraft, namely - an ellipsoid. It is a geometric shape used extensively in aviation, because it has a very low aerodynamic resistance. The resonant response of ellipsoid is evaluated in a decade frequency band, but the pattern recognition of this shape is enough for an octave band. The resonant response is assessed for cross polarization of incident electromagnetic field, as well. As a result, the radio-impulse shape can be used in a data base for pattern recognition.
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.
Structural composites with integrated electromagnetic functionality
Nemat-Nasser, Sia
Structural composites with integrated electromagnetic functionality Syrus C. Nemat-Nasser, Alireza, such as wires, into polymer-based or ceramic-based composites. In addition to desired structural properties, these materials may be leveraged for active tasks such as filtering. The advantages of such hybrid composites
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.
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.
Finite element modeling of electromagnetic NDT phenomena
R. Palanisamy; W. Lord
1979-01-01
The development of computer-based defect characterization schemes for automated electromagnetic methods of nondestructive testing (NDT) requires adequate mathematical models to describe the complicated interactions of currents, fields and defects in materials. This paper describes the finite element equations governing active, residual and eddy current phenomena in materials with discontinuities and magnetic nonlinearity. It is suggested that the resulting magnetic vector
Interior ballistics of a hybrid electromagnetic gun
O. K. Mawardi
1982-01-01
The dynamics for the projectile inside an electromagnetic gun has been developed. The gun consists of a series of stationary cylindrical coils that are pulsed and of one inner concentric coil driven at constant current. The inner coil is the projectile. Two important design parameters are identified: one is the desired exit velocity divided by the square root of the
The ATLAS liquid argon electromagnetic calorimeter
NASA Astrophysics Data System (ADS)
Pralavorio, Pascal; ATLAS Liquid Argon Group
2000-12-01
The ATLAS detector will start operation on the LHC in 2005. The collaboration has chosen a Liquid Argon electromagnetic calorimeter with accordion shape. Modules 0 of the barrel and the endcap were tested under electron beam at CERN during summer 99. The results of these tests are presented as well as the status of the modules' production.
Electromagnetic-wave propagation along curved surfaces
Willatzen, M. [Mads Clausen Institute for Product Innovation, University of Southern Denmark, Alsion 2, DK-6400 Soenderborg (Denmark)
2009-10-15
We show that Maxwell's equations for a nonmagnetic, isotropic, but electrically inhomogeneous medium in the absence of charges or current sources lead to a wave equation governing surface electromagnetic wave propagation along a general curved, smooth surface which, when recasted using an appropriate choice of curvilinear coordinates u{sup 1},u{sup 2},u{sup 3}, can be fully separated in the spatial dimensions. It is shown that surface electromagnetic wave solutions decay exponentially away from the surface (along the u{sup 3} coordinate) with the same decay rate independent of the shape of the surface. Transmission and reflection coefficients governing scattering of electromagnetic waves on a varying surface shape are derived. Two test cases of a Gaussian-shaped and a sinusoidal-shaped surface are solved in details and discussed numerically in terms of transmission and reflection coefficients including dependencies on surface-shape parameters in the wavelength range 250-750 nm. The present method for determining surface electromagnetic wave propagation along complex-shaped metal-dielectric surfaces allows better insight into the importance of surface geometry as well as considerably faster computational speeds than those provided by standard numerical methods.
Inverse electromagnetic scattering models for sea ice
K. M. Goldenl; D. Borup; M. Cheney; E. Cherkaeva; M. S. Dawson; Kung-Hau Ding; A. K. Fung; D. Isaacson; S. A. Johnson; Arthur K. Jordan; Jin Au Kong; Ronald Kwok; Son V. Nghiem; Robert G. Onstott; J. Sylvester; D. P. Winebrenner; I. H. H. Zabel
1998-01-01
Inverse scattering algorithms for reconstructing the physical properties of sea ice from scattered electromagnetic field data are presented. The development of these algorithms has advanced the theory of remote sensing, particularly in the microwave region, and has the potential to form the basis for a new generation of techniques for recovering sea ice properties, such as ice thickness, a parameter
Scattering of Electromagnetic Waves, Advanced Topics
Leung Tsang; Jin Au Kong
2001-01-01
A timely and authoritative guide to the state of the art of wave scattering Scattering of Electromagnetic Waves offers in three volumes a complete and up-to-date treatment of wave scattering by random discrete scatterers and rough surfaces. Written by leading scientists who have made important contributions to wave scattering over three decades, this new work explains the principles, methods, and
Electromagnetic wave scattering from rough terrain
R. J. Papa; J. F. Lennon; R. L. Taylor
1980-01-01
This report presents two aspects of a program designed to calculate electromagnetic scattering from rough terrain: (1) the use of statistical estimation techniques to determine topographic parameters and (2) the results of a single-roughness-scale scattering calculation based on those parameters, including comparison with experimental data. In the statistical part of the present calculation, digitized topographic maps are used to generate
Scattering of Electromagnetic Waves, Numerical Simulations
Leung Tsang; Jin Au Kong; Kung-Hau Ding; Chi On Ao
2001-01-01
A timely and authoritative guide to the state of the art of wave scattering Scattering of Electromagnetic Waves offers in three volumes a complete and up-to-date treatment of wave scattering by random discrete scatterers and rough surfaces. Written by leading scientists who have made important contributions to wave scattering over three decades, this new work explains the principles, methods, and
Electromagnetic waves in the atmosphere and space
A. V. Sokolov; A. A. Semenov
1986-01-01
The papers presented in this volume provide an overview of recent research related to the propagation of electromagnetic waves of various wavelengths at ground and space paths, in the troposphere, and in plasma media. Topics discussed include radio wave propagation in an anisotropic turbulent atmosphere, propagation and scattering of millimeter waves, attenuation of radio waves in rain and its prediction,
Metasurfaces for general transformations of electromagnetic fields.
Tretyakov, S A
2015-08-28
In this review paper I discuss electrically thin composite layers, designed to perform desired operations on applied electromagnetic fields. Starting from a historical overview and based on a general classification of metasurfaces, I give an overview of possible functionalities of the most general linear metasurfaces. The review is concluded with a short research outlook discussion. PMID:26217052
Complementary Electromagnetic Non-Destructive Evaluation
NASA Astrophysics Data System (ADS)
Tian, Gui Yun; Wilson, John; Morozov, Maxim
2011-06-01
The use of non-destructive evaluation (NDE) for defect detection and failure prediction in structures and specimens is widespread in energy industries, aimed at ageing power plants and pipelines, material degradation, fatigue and radiation damage, etc. At present there are no suitable electromagnetic NDE methods for the measurement and characterization of material degradation, in irradiated samples in particular, which is very important and timely for the nuclear power industry in the UK. This paper reports recent developments in the field of electromagnetic (EM) NDE at Newcastle University, including pulsed eddy current (PEC), pulsed magnetic flux leakage (PMFL), magnetic Barkhausen emission (MBE) and magneto-acoustic emission (MAE). As different EM methods have different strengths, an integrative EM framework is introduced. Case studies through the second round robin tests organized by the Universal Network for Magnetic Non-Destructive Evaluation (UNMNDE), representing eighteen leading research groups worldwide in the area of electromagnetic NDE, are reported. Twelve samples with different ageing times and rolling reduction ratios were tested using different magnetic methods among the UNMNDE members. Based on the studies, the complementary characteristics of electromagnetic techniques for NDE are discussed.
Radiation from electromagnetically driven Langmuir turbulence
Mjolhus, E.; Hanssen, A. [Univ. of Tromso (Norway)] [Univ. of Tromso (Norway); DuBois, D.F. [Los Alamos National Lab., NM (United States)] [Los Alamos National Lab., NM (United States)
1995-09-01
A two-level model for the interaction between the electromagnetic pump wave and the electrostatic turbulence is formulated for ionospheric radio modification experiments. On the local level, the Zakharov equations, or similar models, apply. The interaction with the global electromagnetic level is represented by a second-order current density averaged over the local spatial variable. The energy exchange between the local and global level is represented by a Joulean product involving this second-order current density. The global generation problem is solved in the simplest cases. The escaping energy flux in the sideband {omega} is shown to be represented as a folding between the power spectrum of the local source and a squared Airy function. This power spectrum has been calculated from numerical simulations of electromagnetically driven Langmuir turbulence, using a one-dimensional model of the Zakharov type, for varying values of the parameters. For parameters in the cascade range, narrow line structured spectra were obtained, while for parameters in the cavitation range, very broad featureless spectra were obtained. Comparison with recent experimental stimulated electromagnetic emissions data did not confirm a signature for the existence of cavitation in the experiments. 67 refs., 7 figs.
Theory of electromagnetic reactions in light nuclei
Xu, Tianrui; Bacca, Sonia; Hagen, Gaute
2015-01-01
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.
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 interactions of cosmic rays with nuclei
NASA Technical Reports Server (NTRS)
Norbury, John W.
1989-01-01
Parameterizations of single nucleon emission from the electromagnetic interactions of cosmic rays with nuclei are presented. These parameterizations are based upon the most accurate theoretical calculations available today. When coupled with Strong interaction parameterizations, they should be very suitable for use in cosmic ray propagation through intersteller space, the Earth's atmosphere, lunar samples, meteorites and spacecraft walls.
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.
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,…
The ATLAS liquid-argon electromagnetic calorimeter
NASA Astrophysics Data System (ADS)
Zolnierowski, Yves; Atlas Collaboration
1996-12-01
Using test-beam results from the RD3 collaboration, the ATLAS liquid-argon electromagnetic calorimeter has been optimized for the search for the decay of the Higgs boson in two photons. Other physics topics add fewer constraints. We present the choices made for the following items: lead thickness, sampling depth, implementation of the preshower and high-granularity sections.
Electromagnetic Siegert states for periodic dielectric structures
Ndangali, Friends R
2011-01-01
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...
Electromagnetic Emission Rates and Spectral Sum Rules
James Steele; Hidenaga Yamagishi; Ismail Zahed
1998-02-05
The electromagnetic emission rates at SPS energies satisfy spectral constraints in leading order in the pion and nucleon densities. These constraints follow from the strictures of broken chiral symmetry. We saturate these constraints using available data, leading to model independent emission rates from a hadronic gas. With a simple fire-ball scenario, only large nucleon densities may account for the present CERES data.
Electromagnetic cavity to explore disordered systems
Marc Bastuscheck; Fredy Zypman
2007-01-01
In the course of characterizing an electromagnetic cavity we have come to understand details of transmission and reflection traces, some of which may be useful as tools to investigate local modes in random media. We have demonstrated quantitative agreement of frequency shift observations with theory, have demonstrated that the spatial distribution of electric and magnetic fields can be measured using
MRI electromagnetic field penetration in cylindrical objects
Fredy R. Zypman
1996-01-01
Magnetic Resonance Imaging information depends on the knowledge of the behavior of the transverse, radio frequency (RF) electromagnetic fields inside biological objects. Here we present exact results for the RF vector potential field inside and outside a cylindrical object that minics the human body. These results are obtained by solving Maxwell Equations with appropriate boundary conditions, and take into consideration
Electromagnetic driving units for complex microrobotic systems
NASA Astrophysics Data System (ADS)
Michel, Frank; Ehrfeld, Wolfgang; Berg, Udo; Degen, Reinhard; Schmitz, Felix
1998-10-01
Electromagnetic actuators play an important role in macroscopic robotic systems. In combination with motion transformers, like reducing gear units, angular gears or spindle-screw drives, electromagnetic motors in large product lines ensure the rotational or linear motion of robot driving units and grippers while electromagnets drive valves or part conveyors. In this paper micro actuators and miniaturized motion transformers are introduced which allow a similar development in microrobotics. An electromagnetic motor and a planetary gear box, both with a diameter of 1.9 mm, are already commercially available from the cooperation partner of IMM, the company Dr. Fritz Faulhaber GmbH in Schonaich, Germany. In addition, a motor with a diameter of 2.4 mm is in development. The motors successfully drive an angular gear and a belt drive. A linear stage with a motion range of 7 mm and an overall size as small as 5 X 3.5 X 24 mm3 has been realized involving the motor, a stationary spur gear with zero backlash and a spindle-screw drive. By the use of these commercially available elements complex microrobots can be built up cost-efficiently and rapidly. Furthermore, a batch process has been developed to produce the coils of micro actuator arrays using lithographic techniques with SU-8 resin. In applying these components, the modular construction of complex microrobotic systems becomes feasible.
Unique Signal Override Plug electromagnetic test report
Bonn, R.H.
1990-10-01
The MC4039 Unique Signal Override Plug (USOP) provides the unique signal for the B90 when fielded on aircraft that are not equipped with unique signal capability. Since the USOP is field installed, the concern is that it might be susceptible to electromagnetic radiation prior to installation on the weapon. This report documents a characterization of the USOP, evaluates various techniques for attaching electromagnetic shields, and evaluates the susceptibility of a fully assembled passive-USOP. Tests conducted evaluated the electromagnetic susceptibility of the passive, unconnected USOP. During normal operation the USOP is powered directly from the weapon. During the course of this test program two prototypes were developed. The prototype 1 USOP internal circuitry contains one SA3727 chip, five diodes, three resistors, and two capacitors; these are mounted on a circular circuit board and contained inside a metal back shell cover, which serves as an electromagnetic shield. The prototype 2 design incorporated four changes. The manufacturer of the SA3727 chip was changed from Lasarray to LSI Logic, the circuit board ground was tied to the case ground through a straight wire, Cl was changed from 1 microfarad to 0.1 microfarads. and the circuit board was changed, as required. 2 refs., 17 figs., 3 tabs. (JF)
Active source electromagnetic methods for marine munitions
NASA Astrophysics Data System (ADS)
Schultz, Gregory; Shubiditze, Fridon; Miller, Jonathan; Evans, Rob
2011-06-01
The detection of munitions targets obscured in coastal and marine settings has motivated the need for advanced geophysical technologies suited for underwater deployment. Building on conventional marine electromagnetic theory and based on the use of existing electric and magnetic field sensing designs, we analyze the electromagnetic fields emitted from excited targets in the frequency range between 1 kHz and 1 MHz. We present evidence that employing electromagnetic modes that are higher in frequency relative to those typically used in ground-based sensing yields greater range and sensitivity for underwater surveys. We develop potential design strategies for implementing both magnetic (B) and electric (E) field sources and sensors in the marine environment, and determine optimal arrangements for a potential combined E- and B-field sensing system. The implementation of both 1D analytical and 3D numerical simulations yields the primary and secondary field distributions in representative underwater settings for various sourcereceiver arrangements. We study the electromagnetic field distributions from both electric (voltage-fed dipole) and magnetic field (encased and submerged induction coil) active sources. Application of these concepts provide unique and useful information about targets from the addition of electric field sensing alone as well as through the combination of electric and magnetic field sensing.
Spacetime Deformations and Electromagnetism in Material Media
R. da Rocha; I. L. Freire
2005-03-07
This paper is intended to investigate the relation between electrodynamics in anisotropic material media and its analogous formulation in an spacetime, with non-null Riemann curvature tensor. After discussing the electromagnetism via chiral differential forms, we point out the optical activity of a given material medium, closely related to topological spin, and the Faraday rotation, associated to topological torsion. Both quantities are defined in terms of the magnetic potential and the electric and magnetic fields and excitations. We revisit some properties of material media and the associated Green dyadics. Some related features of ferrite are also investigated. It is well-known that the constitutive tensor is essentially equivalent to the Riemann curvature tensor. In order to investigate the propagation of electromagnetic waves in material media, we prove that it is analogous to consider the electromagnetic wave propagation in the vacuum, but this time in a curved spacetime, which is obtained by a deformation of the lorenztian metric of Minkowski spacetime. Spacetime deformations leave invariant the form of Maxwell equations. Also, there exists a close relation between Maxwell equations in curved spacetime and in an anisotropic material medium, indicating that electromagnetism and spacetime properties are deeply related. Besides, the geometrical aspects of wave propagation can be described by an effective geometry which represents a deformation of the lorentzian metric of Minkowski spacetime.
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
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.
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.
Transition electromagnetic fields in particle physics
Abdus Salam; J. Strathdee
1975-01-01
We present a computation of one-loop effective potentials for elementary systems placed in a strong magnetic or a laser-produced electromagnetic environment. This permits a determination in principle of a hierarchy of transition field strengths, for which the systems concerned may (for appropriate values of the parameters in the theory) make transitions from a spontaneously broken asymmetric phase to one of
-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
Electromagnetic optimization exploiting aggressive space mapping
John W. Bandler; R. M. Biernacki; Shao Hua Chen; Ronald H. Hemmers; Kaj Madsen
1995-01-01
We propose a significantly improved space mapping (SM) strategy for electromagnetic (EM) optimization. Instead of waiting for upfront EM analyses at several base points, our new approach aggressively exploits every available EM analysis, producing dramatic results right from the first step. We establish a relationship between the novel SM optimization and the quasi-Newton iteration for solving a system of nonlinear
Electromagnetic interactions in Halo Effective Field Theory
Renato Higa
2010-01-04
After a brief discussion of effective field theory applied to nuclear clusters, I concentrate on the inclusion of two particular aspects, namely, narrow resonances and electromagnetic interactions. As examples of applications, I present the details of our studies on alpha-alpha and proton-alpha scattering.
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…
Calculating Electromagnetic Fields Of A Loop Antenna
NASA Technical Reports Server (NTRS)
Schieffer, Mitchell B.
1987-01-01
Approximate field values computed rapidly. MODEL computer program developed to calculate electromagnetic field values of large loop antenna at all distances to observation point. Antenna assumed to be in x-y plane with center at origin of coordinate system. Calculates field values in both rectangular and spherical components. Also solves for wave impedance. Written in MicroSoft FORTRAN 77.
Progress in Electromagnetic Launch Science and Technology
Harry D. Fair
2007-01-01
Electromagnetic (EM) launch science and technology in the United States continues to advance at a significant pace. The computational and experimental tools for understanding the critical physics issues are sufficiently mature that they are being utilized to provide insight and resolution of the remaining major technical challenges. For example, the primary computational electrodynamics code, EMAP3D, is now implemented in a
Relations Among Systems of Electromagnetic Equations
ERIC Educational Resources Information Center
page, Chester H.
1970-01-01
Contends that the equations of electromagnetism, whether in rationalized or non-rationalized form, express an invariant set of physical relationships. The relationships among corresponding symbols are given and applied to precise statements about the relation between the oersted and the amphere per meter, the abampere and the ampere, etc.…
Electromagnetism Adapted for Life Science Students
ERIC Educational Resources Information Center
Gurr, F. M.; And Others
1974-01-01
Describes the study of electronics as a terminal course in electromagnetism. A lecture-laboratory approach is used with a strong emphasis on practical experience. Outlines the major topics of the lecture program and describes the activities used in the laboratory. (GS)
Electromagnetic Radiation and Motion of Real Particle
Jozef Klacka
2001-06-21
Relativistically covariant equation of motion for real dust particle under the action of electromagnetic radiation is derived. The particle is neutral in charge. Equation of motion is expressed in terms of particle's optical properties, standardly used in optics for stationary particles.
Out-of-equilibrium electromagnetic radiation
Julien Serreau
2004-06-22
We derive general formulas for photon and dilepton production rates from an arbitrary non-equilibrated medium from first principles in quantum field theory. At lowest order in the electromagnetic coupling constant, these relate the rates to the unequal-time in-medium photon polarization tensor and generalize the corresponding expressions for a system in thermodynamic equilibrium. We formulate the question of electromagnetic radiation in real time as an initial value problem and consistently describe the virtual electromagnetic dressing of the initial state. In the limit of slowly evolving systems, we recover known expressions for the emission rates and work out the first correction to the static formulas in a systematic gradient expansion. Finally, we discuss the possible application of recently developed techniques in non-equilibrium quantum field theory to the problem of electromagnetic radiation. We argue, in particular, that the two-particle-irreducible (2PI) effective action formalism provides a powerful resummation scheme for the description of multiple scattering effects, such as the Landau-Pomeranchuk-Migdal suppression recently discussed in the context of equilibrium QCD.
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.
NASA Astrophysics Data System (ADS)
Prudêncio, Filipa R.; Matos, Sérgio A.; Paiva, Carlos R.
2014-11-01
The concept of a perfect electromagnetic conductor (PEMC) was introduced to generalize and unify two well-known and apparently disjoint concepts in electromagnetics: the perfect electric conductor (PEC) and the perfect magnetic conductor (PMC). Although the PEMC has proven a fertile tool in electromagnetic analyses dealing with new and complex boundaries, its corresponding definition as a medium has, nevertheless, raised several problems. In fact, according to its initial 3D definition, the PEMC cannot be considered a unique and well-defined medium: it leads to extraneous fields without physical meaning. By using a previously published generalization of a PEMC that regards this concept both as a boundary and as a medium - which was dubbed an MIM (Minkowskian isotropic medium) and acts, in practice, as an actual electromagnetic conductor (EMC) - it is herein presented a straightforward analysis of waveguides containing PEMCs that readily and systematically follows from the general framework of waveguides containing EMCs.
NASA Astrophysics Data System (ADS)
Guo, Qingwei; Gao, Min; Lu, Zhicai; Yang, Peijie
2013-03-01
Accurate measurement of angular motion has long been recognized as a daunting task. In recent years the measurement of projectiles utilizing magnetic resistance sensors has become a hot research field. Electromagnetic interference on attitude measurement cannot be ignored in complex electromagnetic environments such as battlefield conditions. In this paper, the influence and function pattern of electromagnetic interference on the measuring performance are theoretically analyzed, and the shielding effectiveness (SE) simulation of projectile is conducted via software Computer Simulation Technology (CST). Considering the specific tests, the intensity of the influence is judged. The simulation indicates that the battlefield's complex electromagnetic environment influences the environment inside the projectile, especially its electronic components and capability. The research results can provide important theoretical support on the errors compensation and precision improvement of the projectile attitude measurement with Magnetic Resistance sensor.
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.
Oil recovery apparatus using an electromagnetic pump drive
1988-01-01
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
The Inverse Electromagnetic Scattering Problem for Anisotropic Media
Cakoni, Fioralba
will formulate the direct scattering problem for time harmonic electromagnetic waves in an anisotropic mediumThe Inverse Electromagnetic Scattering Problem for Anisotropic Media Fioralba Cakoni1 , David. The inverse electromagnetic scattering problem for anisotropic media plays a special role in inverse
Scattering of Ordinary Electromagnetic Wave on the Kinetic Alfvén Wave
A. K. Yukhimuk; V. A. Yukhimuk; O. G. Fal'Ko; E. K. Sirenko
1999-01-01
The scattering of ordinary electromagnetic wave on kinetic Alfvén wave in the magnetized plasma with a small plasma parameter beta is investigated. The nonlinear dispersion equation and instability growth rates are found on the basis of two-fluid magnetohydrodynamics. It is shown that an ordinary electromagnetic wave may decay into a kinetic Alfvén wave and an other ordinary electromagnetic wave. The
Angular correlation function and scattering coefficient of electromagnetic waves
Zhang, Guifu
Angular correlation function and scattering coefficient of electromagnetic waves scattered We study three-dimensional (3-D) electromagnetic wave scattering from a buried object under a two-3232(98)00412-8] OCIS codes: 290.0290, 290.5880. 1. INTRODUCTION The study of electromagnetic wave scattering
Electromagnetic wave scattering by many conducting small particles
Electromagnetic wave scattering by many conducting small particles A. G. Ramm Department theory of electromagnetic (EM) wave scattering by small perfectly conducting particles is developed-matrix for acoustic and electromagnetic (EM) wave scattering by small bodies of arbitrary shapes. These formulas allow
Scattering of Electromagnetic Waves by Periodic Rough Surfaces
S Yildiz; Y Altuncu; O Ozdemir
2006-01-01
Periodic structures often appear in the applications such as antenna design, microwave systems, metamaterials etc. and the analysis of electromagnetic wave propagation in such structures has an important place in the electromagnetic theory. Among them scattering of electromagnetic waves from rough surfaces is important due to both theoretical and practical points of view. For the periodic surfaces having a slow
Scattering of electromagnetic waves by many Department of Mathematics
Scattering of electromagnetic waves by many nano-wires A G Ramm Department of Mathematics Kansas There is a large literature on electromagnetic (EM) wave scattering by an array of parallel cylinders (see, e.g., [2], where there are many references given, and [3]). Electromagnetic wave scattering by many
UNIQUENESS IN INVERSE OBSTACLE SCATTERING FOR ELECTROMAGNETIC WAVES
Wardetzky, Max
UNIQUENESS IN INVERSE OBSTACLE SCATTERING FOR ELECTROMAGNETIC WAVES Rainer Kress Institut f to Potthast. THE INVERSE OBSTACLE SCATTERING PROBLEM The propagation of time-harmonic electromagnetic waves-harmonic electromagnetic waves. We will concentrate on uniqueness issues, i.e., we will investigate under what conditions
A novel integrated approach for simulation of electromagnetic susceptibility problem
Hong-Fang Jin; Er-Ping Li; En-Xiao Liu
2005-01-01
This paper presents a systematic approach for electromagnetic susceptibility (EMS) analysis of high speed circuit with the presence of an electromagnetic interference. With numerical analysis, the effect of external electromagnetic noise on the interconnect is characterized and modeled as equivalent current source. At the same time, the macromodel of Internet subnetwork is constructed through vector fitting method. Then, the resultant
Electromagnetic interaction in the theory of straight strings
Nikitin, I.N.; Pron`ko, G.P. [State Research Center Institute for High-Energy Physics, Protvino (Russian Federation)
1995-06-01
A scheme is proposed for including electromagnetic interaction into the theories of stretched relativistic objects. In the theory of the straight string, the operator of electromagnetic interaction is constructed, and form factors of electromagnetic transitions are calculated. 6 refs., 1 fig.
9. Electromagnetic Calorimeter 9.1. Purpose and Design
conditions have to be maintained. Temperatures and the radiation exposure must be closely monitored66 9. Electromagnetic Calorimeter 9.1. Purpose and Design The electromagnetic calorimeter (EMC) is de signed to measure electromagnetic showers with excellent e#ciency, and energy and angular res
9. Electromagnetic Calorimeter 9.1. Purpose and Design
. Temperatures and the radiation exposure must be closely monitored, and precise calibrations of the electronics66 9. Electromagnetic Calorimeter 9.1. Purpose and Design The electromagnetic calorimeter (EMC) is de- signed to measure electromagnetic showers with excellent efficiency, and energy and angular res
The response functions of electromagnetic wave logs and their applications
Guanglong Xing; Shande Yang
2006-01-01
A fundamental feature of the electromagnetic wave logs is the logging response (phase difference and amplitude ratio) dependent on the both dielectric constant and conductivity in general. We derived the response functions (RF) of the electromagnetic wave logs and proposed their fast algorithm based on an integral equation of electromagnetic field and a weak scattering approximation. Using the fast algorithm
The scattering of electromagnetic waves from rough surfaces
Petr Beckmann; Andre Spizzichino
1987-01-01
The theory and applications of scattering of electromagnetic waves from rough surfaces are addressed. The topics considered include: the general Kirchoff solution for scattering from rough surfaces; periodically rough surfaces; random rough surfaces: surfaces generated by random processes and other models; the statistical distribution of the scattered field; depolarization of electromagnetic waves scattered from a rough surface; reflection of electromagnetic
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
Electromagnetics, 26:335, 2006 Copyright Taylor & Francis Group, LLC
Anlage, Steven
Electromagnetics, 26:335, 2006 Copyright © Taylor & Francis Group, LLC ISSN: 0272-6343 print/1532 the statistical properties of the impedance (Z) and scattering (S) matrices of open electromagnetic cavities. Introduction The problem of the coupling of electromagnetic radiation in and out of structures is a general one
Electromagnetic 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
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
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
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 Dancer: Connect Her Up and Watch Her Dance!
NSDL National Science Digital Library
2014-09-12
In this activity, learners use a nail and magnet wire to build an electromagnet, which controls the movements of a paper dancer. Learners will enjoy watching the dancer swirl around when they activate the electromagnet. Use this activity to help learners explore circuits, electromagnets, and currents. Includes pictures, detailed steps for construction, and focus questions to enhance learning.
Dynamic Electromagnetic Evasion-Pursuit Games with Uncertainty
Dynamic Electromagnetic Evasion-Pursuit Games with Uncertainty H.T. Banks, Shuhua Hu, K. Ito, NC 27695-8212 December 1, 2010 Abstract We consider two player electromagnetic evasion-pursuit games setting. AMS subject classifications: 35Q61,83C50,83C22,65M32. Key Words: Electromagnetic evasion
An inverse electromagnetic scattering problem for , Fioralba Cakoni2
Cakoni, Fioralba
An inverse electromagnetic scattering problem for cavity Fang Zeng1 , Fioralba Cakoni2 and Jiguang@desu.edu, cakoni@math.udel.edu and jsun@desu.edu Abstract. We consider the inverse electromagnetic scattering Publishing for peer review 11 August 2011 #12;An inverse electromagnetic scattering problem for cavity 2 1
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 degree 3 for periods ranging from 9 to 33 days. We show that the sensitivity of the electromagnetic
ECE 202 Fall 2006 Introduction to Engineering Electromagnetics (3)
Gilchrist, James F.
ECE 202 Fall 2006 Introduction to Engineering Electromagnetics (3) Lecture Time: Fall 2006 Electromagnetics, Springer (2003). I consider this as the best undergraduate ECE 202-type textbook. 2. Nelson Tansu, Fundamental of Engineering Electromagnetics, Prentice Hall (2003). Nice and concise treatment of elementary EM
Long Pulse Fusion Physics Experiments Without Superconducting Electromagnets
Long Pulse Fusion Physics Experiments Without Superconducting Electromagnets Robert D. Woolley pulse ignition with DT fuel. 1,2,3,4 Long pulse resistive electromagnets are alternatives to today The main design issue for long pulse resistive electromagnets is heat removal (within stress limitations
Cosmological electromagnetic fields due to gravitational wave perturbations Mattias Marklund*
Dunsby, Peter
show that this coupling leads to an initial pulse of electromagnetic waves whose width and amplitude to produce a pulse of gravitationally induced electromagnetic waves. In particular, because of the differentCosmological electromagnetic fields due to gravitational wave perturbations Mattias Marklund
Long Pulse Fusion Physics Experiments Without Superconducting Electromagnets
Long Pulse Fusion Physics Experiments Without Superconducting Electromagnets Robert D. Woolley pulse ignition with DT fuel. 1,2,3,4 Long pulse resistive electromagnets are alternatives to today. INTRODUCTION The main design issue for long pulse resistive electromagnets is heat removal (within stress
CONTROL ORIENTATED SYNTHESIS OF ELECTROMAGNETIC SHUNT IMPEDANCES FOR
Fleming, Andrew J.
to the terminals of an electromagnetic coil, the rela- tive mechanical velocity between the coil and magnet canCONTROL ORIENTATED SYNTHESIS OF ELECTROMAGNETIC SHUNT IMPEDANCES FOR VIBRATION ISOLATION 1 S an electromagnetic transducer to develop the required control forces. In this paper, the technique of sensor
Stopband Prediction with Dispersion Diagram for Electromagnetic Bandgap Structures in
Swaminathan, Madhavan
of electromagnetic waves within a given frequency range are quite effective in suppressing simultaneous switching of interest using full-wave electromagnetic simulation of the entire structure. In contrast, using dispersion coupon of an EBG unit cell placed on the same board. I. INTRODUCTION Electromagnetic interference (EMI
ELECTROMAGNETIC SUBSURFACE IMAGING AT VLF WITH DISTRIBUTED OPTIMIZATION
that are considered interference. We formulate electromagnetic subsurface imaging as an optimization problem con govern electromagnetic wave propagation. Algorithms for approximating the solution to these optimization of electromagnetic ra- dio waves. In the VLF (Very Low Frequency, 3-30kHz) band there are many types of naturally
Understanding Electromagnetic Radiation from an Accelerated William E. Baylis
Understanding Electromagnetic Radiation from an Accelerated Charge William E. Baylis Physics carry an electromagnetic field whose effects propagate in free space at the speed of light in straight still seems somewhat unsatisfying. Any disturbance or information in an electromagnetic field, not just
OKHEP9809 Modebymode summation for the zero point electromagnetic
Milton, Kim
the zero point energy of the electromagnetic field is calculated for the boundary conditions given the zero point energy of an electromagnetic field when the boundary conditions are given on an infiniteOKHEP9809 Modebymode summation for the zero point electromagnetic energy of an infinite
MATHEMATICAL MODEL OF THE INTERACTION PROBLEM BETWEEN ELECTROMAGNETIC FIELD AND
Cakoni, Fioralba
MATHEMATICAL MODEL OF THE INTERACTION PROBLEM BETWEEN ELECTROMAGNETIC FIELD AND ELASTIC BODY F elastic body immersed in the medium e where an electromagnetic field is consid- ered. Furthermore we "electromagnetic field-elastic body" determines that the interaction on the boundary must
On flows induced by electromagnetic fields Literature review
Vuik, Kees
On flows induced by electromagnetic fields Literature review Michiel de Reus March 14, 2012 #12;Introduction The goal of my thesis project is to investigate what the influence of an electromagnetic field of the movement of the fluid, there will be feedback to the electromagnetic field itself. The aim here
APPROXIMATION OF ELECTROMAGNETIC FIELDS: PART I. CONTINUOUS PROBLEMS #
Sheen, Dongwoo
APPROXIMATION OF ELECTROMAGNETIC FIELDS: PART I. CONTINUOUS PROBLEMS # DONGWOO SHEEN + SIAM J. APPL Âelectric and magnetic current densities, electromagnetic field intensities are shown to exist uniquely are primarily interested in the numerical approximation of electromagnetic fields propagating in infinite media
Interaction of partially ionized plasmas with electromagnetic fields
Bonitz, Michael
Interaction of partially ionized plasmas with electromagnetic fields D Kremp1, D Semkat1, Th with an electromagnetic field is investigated using quantum statistical methods. A general statistical expression for the current density of a plasma in an electromagnetic field is presented and considered in the high field
Admissible Symmetries of the Electromagnetic Field in LRS Spacetimes
Watt, Stephen M.
Admissible Symmetries of the Electromagnetic Field in LRS Spacetimes Stephen M. Watt Departments models. Seminal early work [1] considered perfect fluid and perfect fluid with electromagnetic field-examine the classical question of locally rotationally symmetric spacetimes with perfect fluid and electromagnetic field
ELECTRICAL AND COMPUTER ENGINEERING 3105-3106 ELECTROMAGNETIC FIELDS
Kachroo, Pushkin
ELECTRICAL AND COMPUTER ENGINEERING 3105-3106 ELECTROMAGNETIC FIELDS PART I. · Catalog Description upon the theory of electromagnetic fields, expressed most efficiently for more than one hundred years of charged particles in electromagnetic fields. Consequently, students must have Math 2216 or equivalent
ECE 341: Electromagnetic Fields I EM devices and systems
Connors, Daniel A.
ECE 341: Electromagnetic Fields I EM devices and systems - Can compute and analyze potentials conditions to solve complex static and low-frequency electromagnetic-field problems - Can mathematically-frequency electromagnetic- field problems utilizing physical conceptual reasoning and mathematical synthesis of solutions
Relativistic motion in a constant electromagnetic field Siu A. China
Chin, Siu A.
Relativistic motion in a constant electromagnetic field Siu A. China Department of Physics, Texas A online 15 January 2009 For a relativistic charged particle moving in a constant electromagnetic field to a complex electromagnetic field. This work shows that this is not due to some complex formalism used
14:332:382 Electromagnetic Fields Spring 2012
Jiang, Wei
14:332:382 Electromagnetic Fields Spring 2012 Instructor: Prof. Wei Jiang Time & Place: MW 1: (732) 445-2164 Course Catalog Description: 14:332:382 Electromagnetic Fields (3) Pre-Requisite Courses:640:314 Elementary Differential Equation and 50:750:234 Electric Circuits II Textbook: Engineering Electromagnetics/7
Psychological Effects of Occupational Exposure to Electromagnetic Fields
Yousefi HA; Nasiri P
Background: In psychological studies, exposure to electromagnetic field is one of the hazardous factors, which has adverse effects on mental health. Exposure to electromagnetic field due to daily use of electricity makes this study so important. The goal of this study was to determine the relationship between psychologi- cal symptoms and occupational exposure to electromagnetic field among workers at High
Electromagnetic Generators and Detectors of Gravitational Waves
L. P. Grishchuk
2003-06-03
The renewed serious interest to possible practical applications of gravitational waves is encouraging. Building on previous work, I am arguing that the strong variable electromagnetic fields are appropriate systems for the generation and detection of high-frequency gravitational waves (HFGW). The advantages of electromagnetic systems are clearly seen in the proposed complete laboratory experiment, where one has to ensure the efficiency of, both, the process of generation and the process of detection of HFGW. Within the family of electromagnetic systems, one still has a great variety of possible geometrical configurations, classical and quantum states of the electromagnetic field, detection strategies, etc. According to evaluations performed 30 years ago, the gap between the HFGW laboratory signal and its level of detectability is at least 4 orders of magnitude. Hopefully, new technologies of today can remove this gap and can make the laboratory experiment feasible. The laboratory experiment is bound to be expensive, but one should remember that a part of the cost is likely to be reimbursed from the Nobel prize money ! Electromagnetic systems seem also appropriate for the detection of high-frequency end of the spectrum of relic gravitational waves. Although the current effort to observe the stochastic background of relic gravitational waves is focused on the opposite, very low-frequency, end of the spectrum, it would be extremely valuable for fundamental science to detect, or put sensible upper limits on, the high-frequency relic gravitational waves. I will briefly discuss the origin of relic gravitational waves, the expected level of their high-frequency signal, and the existing estimates of its detectability.
V. G. Lapin
2010-01-01
The problem of nonlinear interaction is considered of the falling and reflected electromagnetic waves with forced ion - sound waves in a non-uniform layer of isotropic plasmas. At the present communication we consider plasma disturbances as a result of short electromagnetic impulse. The multiple nonstationary scattering of the electromagnetic wave on ion sounding waves is investigated with application of numerical
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.
Electromagnetic field radiation model for lightning strokes to tall structures
Motoyama, H.; Janischewskyj, W.; Hussein, A.M.; Chisholm, W.A.; Chang, J.S.; Rusan, R.
1996-07-01
This paper describes observation and analysis of electromagnetic field radiation from lightning strokes to tall structures. Electromagnetic field waveforms and current waveforms of lightning strokes to the CN Tower have been simultaneously measured since 1991. A new calculation model of electromagnetic field radiation is proposed. The proposed model consists of the lightning current propagation and distribution model and the electromagnetic field radiation model. Electromagnetic fields calculated by the proposed model, based on the observed lightning current at the CN Tower, agree well with the observed fields at 2km north of the tower.
Applications of the electromagnetic Helmholtz resonator*
NASA Astrophysics Data System (ADS)
Stoneback, Russell Alan
An electromagnetic Helmholtz resonator comprised of a capacitor with an aperture is investigated theoretically and experimentally. It is proposed that this resonance may be described using effective impedances describing the capacitor and aperture, similar to lumped element descriptions of the acoustic Helmholtz resonator. The dipole impedance of an electromagnetic aperture is derived and verified using the finite element method. Incorporating standard network relations, the aperture impedance can be used to calculate radiated power. Measurements of a capacitor demonstrates that the transmitted voltage through the capacitor is modified by induced charges. An induced voltage is introduced, and predictions agree with observations. Measurements of a capacitor with an aperture in the grounded plate indicate that induced currents cancel the imaginary impedance of the aperture, and double the real impedance. The observed impedance is close to predictions using the derived aperture impedance, confirming the utility of the aperture impedance in describing the system. The numerically obtained aperture electromagnetic fields are similar to the Birkeland current distribution and the cross polar cap potential in the Earth's polar ionosphere, motivating a model where the polar ionosphere is treated as an effective aperture. It is proposed that this effective aperture interacts with the capacitor formed between the Earth and ionosphere, creating an electromagnetic Helmholtz resonator. Predictions made with this model agree with measurements of transmitted power and phase velocity by FAST during a geomagnetic substorm, measurements of the Ionospheric Alfven Resonator, and oscillations recorded by ground based magnetometers. The same effective aperture behavior is expected in sunspots and polar coronal holes. A peak is predicted in Alfven wave power across the transition region for waves with a 5 min. period that delivers an average power over 100 W/m2 to the corona, sufficient to heat the quiet corona and launch the solar wind. Applied to sunspots, a minimum umbral temperature of 3750 K is predicted with a peak in transmitted power at 3 min., consistent with observations. A prototype electromagnetic guitar and associated methods to obtain music are also presented. These instruments replace the acoustic systems normally employed for musical instruments with electromagnetic equivalents and music samples are presented. *U.S. PATENTS PENDING 20070017344, 20070017345, 20070214940
Vibration based electromagnetic micropower generator on silicon
NASA Astrophysics Data System (ADS)
Kulkarni, Santosh; Roy, Saibal; O'Donnell, Terence; Beeby, Steve; Tudor, John
2006-04-01
This paper discusses the theory, design and simulation of electromagnetic micropower generators with electroplated micromagnets. The power generators are fabricated using standard microelectromechanical system processing techniques. Electromagnetic two-dimensional finite element anlysis simulations are used to determine voltage and power that can be generated from different designs. This paper reports a maximum voltage and power of 55 mV and 70 ?W for the first design, incorporating microfabricated two-layer Cu coils on a Si paddle vibrating between two sets of oppositely polarized electroplated Co50Pt50 face centered tetragonal phase hard magnets. A peak voltage and power of 950 mV and 85 ?W are obtained for the second design, which includes electroplated Ni45Fe55 as a soft magnetic layer underneath the hard magnets. The volume of the device is about 30 mm3.
Electromagnetic Scattering by Spheres of Topological Insulators
Ge, Lixin; Zi, Jian
2015-01-01
The electromagnetic scattering properties of topological insulator (TI) spheres are systematically studied in this paper. Unconventional backward scattering caused by the topological magneto-electric (TME) effect of TIs are found in both Rayleigh and Mie scattering regimes. This enhanced backward scattering can be achieved by introducing an impedance-matched background which can suppress the bulk scattering. For the cross-polarized scattering coefficients, interesting antiresonances are found in the Mie scattering regime, wherein the cross-polarized electromagnetic fields induced by the TME effect are trapped inside TI spheres. In the Rayleigh limit, the quantized TME effect of TIs can be determined by measuring the electric-field components of scattered waves in the far field.
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...
Fluidic electrodynamics: Approach to electromagnetic propulsion
Martins, Alexandre A.; Pinheiro, Mario J. [Institute for Plasmas and Nuclear Fusion and Instituto Superior Tecnico Lisboa, Portugal 351.1.21.841.92.43 (Portugal); Department of Physics and Institute for Plasmas and Nuclear Fusion and Instituto Superior Tecnico Lisboa, Portugal 351.1.21.841.93.22 (Portugal)
2009-03-16
We report on a new methodological approach to electrodynamics based on a fluidic viewpoint. We develop a systematic approach establishing analogies between physical magnitudes and isomorphism (structure-preserving mappings) between systems of equations. This methodological approach allows us to give a general expression for the hydromotive force, thus re-obtaining the Navier-Stokes equation departing from the appropriate electromotive force. From this ground we offer a fluidic approach to different kinds of issues with interest in propulsion, e.g., the force exerted by a charged particle on a body carrying current; the magnetic force between two parallel currents; the Magnus's force. It is shown how the intermingle between the fluid vector fields and electromagnetic fields leads to new insights on their dynamics. The new concepts introduced in this work suggest possible applications to electromagnetic (EM) propulsion devices and the mastery of the principles of producing electric fields of required configuration in plasma medium.
Electromagnetically Induced Transparency for X Rays
Buth, Christian; Santra, Robin; Young, Linda [Argonne National Laboratory, Argonne, Illinois 60439 (United States)
2007-06-22
Electromagnetically induced transparency is predicted for x rays in laser-dressed neon gas. The x-ray photoabsorption cross section and polarizability near the Ne K edge are calculated using an ab initio theory suitable for optical strong-field problems. The laser wavelength is tuned close to the transition between 1s{sup -1}3s and 1s{sup -1}3p ({approx}800 nm). The minimum laser intensity required to observe electromagnetically induced transparency is of the order of 10{sup 12} W/cm{sup 2}. The ab initio results are discussed in terms of an exactly solvable three-level model. This work opens new opportunities for research with ultrafast x-ray sources.
Gravito-electromagnetic Effects of Massive Rings
Matteo Luca Ruggiero
2015-04-27
The Einstein field equations in linear post-Newtonian approximation can be written in analogy with electromagnetism, in the so-called gravito-electromagnetic formalism. We use this analogy to study the gravitational field of a massive ring: in particular, we consider a continuous mass distribution on Keplerian orbit around a central body, and we work out the gravitational field generated by this mass distribution in the intermediate zone between the central body and the ring, focusing on the gravito-magnetic component that originates from the rotation of the ring. In doing so, we generalize and complement some previous results that focused on the purely Newtonian effects of the ring (thus neglecting its rotation) or that were applied to the case of rotating spherical shells. Eventually, we study in some simple cases the effect of the the rotation of the ring, and suggest that, in principle, this approach could be used to infer information about the angular momentum of the ring.
Gravito-electromagnetic Effects of Massive Rings
Ruggiero, Matteo Luca
2015-01-01
The Einstein field equations in linear post-Newtonian approximation can be written in analogy with electromagnetism, in the so-called gravito-electromagnetic formalism. We use this analogy to study the gravitational field of a massive ring: in particular, we consider a continuous mass distribution on Keplerian orbit around a central body, and we work out the gravitational field generated by this mass distribution in the intermediate zone between the central body and the ring, focusing on the gravito-magnetic component that originates from the rotation of the ring. In doing so, we generalize and complement some previous results that focused on the purely Newtonian effects of the ring (thus neglecting its rotation) or that were applied to the case of rotating spherical shells. Eventually, we study in some simple cases the effect of the the rotation of the ring, and suggest that, in principle, this approach could be used to infer information about the angular momentum of the ring.
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
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.
Pulsed thrust measurements using electromagnetic calibration techniques
NASA Astrophysics Data System (ADS)
Tang, Haibin; Shi, Chenbo; Zhang, Xin'ai; Zhang, Zun; Cheng, Jiao
2011-03-01
A thrust stand for accurately measuring impulse bits, which ranged from 10-1000 ?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 ?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 ?N s with 95% credibility.
Pulsed thrust measurements using electromagnetic calibration techniques.
Tang, Haibin; Shi, Chenbo; Zhang, Xin'ai; Zhang, Zun; Cheng, Jiao
2011-03-01
A thrust stand for accurately measuring impulse bits, which ranged from 10-1000 ?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 ?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 ?N?s with 95% credibility. PMID:21456799
Pulsed thrust measurements using electromagnetic calibration techniques
Tang Haibin; Shi Chenbo; Zhang Xin'ai; Zhang Zun; Cheng Jiao [School of Astronautics, Beijing University of Aeronautics and Astronautics, Beijing 100191 (China)
2011-03-15
A thrust stand for accurately measuring impulse bits, which ranged from 10-1000 {mu}N s using a noncontact electromagnetic calibration technique is described. In particular, a permanent magnet structure was designed to produce a uniform magnetic field, and a multiturn coil was made to produce a calibration force less than 10 mN. The electromagnetic calibration force for pulsed thrust measurements was linear to the coil current and changed less than 2.5% when the distance between the coil and magnet changed 6 mm. A pulsed plasma thruster was first tested on the thrust stand, and afterward five single impulse bits were measured to give a 310 {mu}N s average impulse bit. Uncertainty of the measured impulse bit was analyzed to evaluate the quality of the measurement and was found to be 10 {mu}N s with 95% credibility.
Electromagnetic Pulse from Final Gravitational Stellar Collapse
P. D. Morley; Ivan Schmidt
2002-01-30
We employ an effective gravitational stellar final collapse model which contains the relevant physics involved in this complex phenomena: spherical radical infall in the Schwarzschild metric of the homogeneous core of an advanced star, giant magnetic dipole moment, magnetohydrodynamic material response and realistic equations of state (EOS). The electromagnetic pulse is computed both for medium size cores undergoing hydrodynamic bounce and large size cores undergoing black hole formation. We clearly show that there must exist two classes of neutron stars, separated by maximum allowable masses: those that collapsed as solitary stars (dynamical mass limit) and those that collapsed in binary systems allowing mass accretion (static neutron star mass). Our results show that the electromagnetic pulse spectrum associated with black hole formation is a universal signature, independent of the nuclear EOS. Our results also predict that there must exist black holes whose masses are less than the static neutron star stability limit.
Dielectric sensors based on electromagnetic energy tunneling.
Siddiqui, Omar; Kashanianfard, Mani; Ramahi, Omar
2015-01-01
We show that metallic wires embedded in narrow waveguide bends and channels demonstrate resonance behavior at specific frequencies. The electromagnetic energy at these resonances tunnels through the narrow waveguide channels with almost no propagation losses. Under the tunneling behavior, high-intensity electromagnetic fields are produced in the vicinity of the metallic wires. These intense field resonances can be exploited to build highly sensitive dielectric sensors. The sensor operation is explained with the help of full-wave simulations. A practical setup consisting of a 3D waveguide bend is presented to experimentally observe the tunneling phenomenon. The tunneling frequency is predicted by determining the input impedance minima through a variational formula based on the Green function of a probe-excited parallel plate waveguide. PMID:25835188
Electromagnetic Containerless Processing Facility TEMPUS (Tiegelfreies Elektromagnetisches
NASA Technical Reports Server (NTRS)
1994-01-01
TEMPUS, an electromagnetic levitation facility that allows containerless processing of metallic samples in microgravity, first flew on the IML-2 Spacelab mission. The principle of electromagnetic levitation is used commonly in ground-based experiments to melt and then cool metallic melts below their freezing points without solidification occurring. The TEMPUS operation is controlled by its own microprocessor system; although commands may be sent remotely from the ground and real time adjustments may be made by the crew. Two video cameras, a two-color pyrometer for measuring sample temperatures, and a fast infrared detector for monitoring solidification spikes, will be mounted to the process chamber to facilitate observation and analysis. In addition, a dedicated high-resolution video camera can be attached to the TEMPUS to measure the sample volume precisely.
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.
Electromagnetic scattering on D3-brane spikes
Roland Kirschner; George K. Savvidy
2001-03-15
We consider scattering of electromagnetic plane waves on a D3-brane spike which emanates normal to D3-barne in the extra space direction. We are interested in studying physical effects on D3-brane which are produced by a spike attached to D3-brane. We have observed that the spike sucks almost all electromagnetic radiation and therefore acts like a black hole. This is because absorption cross section for j=1 tends to a constant at low energy limit. This behaviour is appealing for a string interpretation of the spike soliton because the propagation of $j=1$ mode is indeed distinctive. Instead, the scattered part of the radiation on a D3-brane tends to zero demonstrating non-Thompson behaviour.
Mapping electromagnetic fields near a subwavelength hole
NASA Astrophysics Data System (ADS)
Permyakov, D. V.; Mukhin, I. S.; Shishkin, I. I.; Samusev, A. K.; Belov, P. A.; Kivshar, Yu. S.
2014-08-01
We study, both experimentally and theoretically, the scattering of electromagnetic waves by a subwavelength hole fabricated in a thin metallic film. We employ the scanning near-field optical microscopy in order to reconstruct experimentally the full three-dimensional structure of the electromagnetic fields in the vicinity of the hole. We observe an interference of all excited waves with an incident laser beam which allows us to gain the information about the wave phases. Along with the well-known surface plasmon polaritons propagating primarily in the direction of the incident beam polarization, we observe the free-space radiation diffracted by the hole. We compare the experimental results with the fields of pure electric and pure magnetic dipoles as well as with direct numerical simulations. We confirm that a single hole in a thin metallic film excited at the normal incidence manifests itself as an effective magnetic dipole in the visible spectral range.
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 inverse applications for functional brain imaging
Wood, C.C.
1997-10-01
This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). This project addresses an important mathematical and computational problem in functional brain imaging, namely the electromagnetic {open_quotes}inverse problem.{close_quotes} Electromagnetic brain imaging techniques, magnetoencephalography (MEG) and electroencephalography (EEG), are based on measurements of electrical potentials and magnetic fields at hundreds of locations outside the human head. The inverse problem is the estimation of the locations, magnitudes, and time-sources of electrical currents in the brain from surface measurements. This project extends recent progress on the inverse problem by combining the use of anatomical constraints derived from magnetic resonance imaging (MRI) with Bayesian and other novel algorithmic approaches. The results suggest that we can achieve significant improvements in the accuracy and robustness of inverse solutions by these two approaches.
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.
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.