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1

Electromagnets  

NSDL National Science Digital Library

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

2

Electromagnets  

NSDL National Science Digital Library

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

Horton, Michael

2009-05-30

3

Electromagnetic Attraction.  

ERIC Educational Resources Information Center

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)

Milson, James L.

1990-01-01

4

Electromagnetic fasteners  

DOEpatents

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

5

Electromagnetic Math  

NSDL National Science Digital Library

This book offers an introduction to the electromagnetic spectrum using examples of data from a variety of NASA missions and satellite technologies. The 84 problem sets included allow students to explore the concepts of waves, wavelength, frequency, and speed; the Doppler Shift; light; and the energy carried by photons in various bands of the spectrum. Extensive background information is provided which describes the nature of electromagnetic radiation.

6

Electromagnetic Theory 1 /56 Electromagnetic Theory  

E-print Network

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

Bicknell, Geoff

7

Electromagnet Lesson  

NSDL National Science Digital Library

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

Orzali, Joe

2011-12-08

8

Electromagnetic Geometry  

E-print Network

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

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

2011-11-08

9

Electromagnetic Field Theory  

E-print Network

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

Hart, Gus

10

Investigation of electromagnetic welding  

E-print Network

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 ...

Pressl, Daniel G. (Daniel Gerd)

2009-01-01

11

The Electromagnetic Spectrum  

NSDL National Science Digital Library

This web site contains materials about all parts of the electromagnetic spectrum. It describes each space telescope that NASA has launched as well as its observing range in the electromagnetic spectrum.

Astrophysics, Laboratory F.

2004-11-17

12

Electromagnetic Field Exposure Dosimeter.  

National Technical Information Service (NTIS)

The growing concern about adverse health effects caused by electromagnetic radiation prompted the ideas for this dosimeter. Data have been presented that ink prolonged exposure to electromagnetic radiation from power lines to leukemia and some types of ca...

A. C. Feaga, M. P. Hilliard, R. Link

1994-01-01

13

Shape optimization of electromagnet  

Microsoft Academic Search

The paper deals with finding the optimal shape of the electromagnet by changing skew keeper and skew pole shoe of the electromagnet so as to obtain maximum tensile force. The solution used numerical methods, especially the program COMSOL.

S. Zajaczek; L. Skr?iva?nek; L. Iva?nek

2010-01-01

14

Electromagnetic properties of neutrinos  

E-print Network

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

Carlo Giunti; Alexander Studenikin

2010-06-08

15

Electromagnetic Interference (Emi)  

Microsoft Academic Search

\\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

Mike Hardage; Philip D. Henry

16

Electromagnetic Measurements at RHIC  

E-print Network

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

Hamagaki, Hideki

17

Electromagnetic Measurements at RHIC  

E-print Network

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

Hamagaki, Hideki

18

8.07 Electromagnetism II, Fall 2002  

E-print Network

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

Zwiebach, Barton

19

Exploring the Electromagnetic Spectrum  

NSDL National Science Digital Library

Students learn the basics of the electromagnetic spectrum and how various types of electromagnetic waves are related in terms of wavelength and energy. In addition, they are introduced to the various types of waves that make up the electromagnetic spectrum including, radio waves, ultraviolet waves, visible light and infrared waves. These topics help inform students before they turn to designing solutions to an overarching engineering challenge question.

Research Experience for Teachers (RET) Program, Center of Advancement of Engineering Fibers and Films,

20

Meson electromagnetic form factors  

E-print Network

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

Stanislav Dubnicka; Anna Z. Dubnickova

2012-10-23

21

How Strong are Electromagnets?  

NSDL National Science Digital Library

This is an activity about electromagnetism. Using a battery and a length of wire, learners will construct an electromagnet and investigate the number of paperclips the electromagnet can hold for an electromagnet with twenty loops of wire versus one with forty loops of wire. A six to twelve volt battery, a large nail or metal rod, and insulated wire are required for this activity. This is the fourth activity in the Exploring the Earth's Magnetic Field: An IMAGE Satellite Guide to the Magnetosphere educators guide.

22

NISTHB 150-11 Electromagnetic  

E-print Network

NISTHB 150-11 NVLAP Electromagnetic Compatibility and Telecommunications Bethany Hackett Bradley. #12;NISTHB 150-11 NVLAP Electromagnetic Compatibility and Telecommunications Bethany Hackett Bradley Programs Dennis Camell Electromagnetics Division Physical Measurement Laboratory http://dx.doi.org/10

23

Introducing Electromagnetic Field Momentum  

ERIC Educational Resources Information Center

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

Hu, Ben Yu-Kuang

2012-01-01

24

Electromagnetic compatibility overview  

NASA Technical Reports Server (NTRS)

An assessment of the electromagnetic compatibility impact of the Satellite Power System is discussed. The discussion is divided into two parts: determination of the emission expected from SPS including their spatial and spectral distributions, and evaluation of the impact of such emissions on electromagnetic systems including considerations of means for mitigating effects.

Davis, K. C.

1980-01-01

25

Tunability enhanced electromagnetic wiggler  

DOEpatents

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.

Schlueter, Ross D. (Albany, CA); Deis, Gary A. (Livermore, CA)

1992-01-01

26

Tunability enhanced electromagnetic wiggler  

DOEpatents

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.

Schlueter, R.D.; Deis, G.A.

1992-03-24

27

The Electromagnetic Spectrum  

NSDL National Science Digital Library

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

28

The Electromagnetic Spectrum  

NSDL National Science Digital Library

This tutorial introduces students to the concepts of electromagnetic waves, wavelength, and the electromagnetic spectrum. Diagrams and written descriptions explain how wavelength is measured and explore the traditional divisions of the spectrum: radio, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays.

29

SMILE Lab: Electromagnets  

NSDL National Science Digital Library

This site contains instructions for a fairly simple lab or demonstration using electromagnets. The electromagnets are made with nails, copper wire, and batteries. The lab includes a list of needed materials, the procedure that the students should follow, and a brief discussion of the physical concepts involved.

Johnson, Porter

2006-07-18

30

Electromagnetic Analysis: Concrete Results  

Microsoft Academic Search

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

Karine Gandolfi; Christophe Mourtel; Francis Olivier

2001-01-01

31

Electromagnetic interference in balanced converters .  

E-print Network

??In this dissertation, an investigation into reducing Electromagnetic Interference (EMI) through design is presented. Root generation mechanisms of Electromagnetic Interference are often neglected during the (more)

Burford, Steven Trefor

2014-01-01

32

Electromagnetic conic sections Tevian Draya)  

E-print Network

Electromagnetic conic sections Tevian Draya) Department of Mathematics, Oregon State University electromagnetic conic sections. We then give a necessary and sufficient condition for a given vector field

33

I. What is electromagnetic radiation and the electromagnetic spectrum?  

E-print Network

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

Sitko, Michael L.

34

Electromagnetic Abdulaziz Hanif  

E-print Network

of these wire strands will be wrapped into a cable. This electromagnet is then super-cooled with liquid helium are better conductors and have a greater effect on the magnetic field. The plate would be charged up

Masoudi, Husain M.

35

The Electromagnetic Spectrum  

NSDL National Science Digital Library

This interactive, online module reviews the basics of the the electromagnetic spectrum and makes the connection between radiation theory and the images we get from weather satellites. Students will learn about: the electromagnetic spectrum; electromagnetic waves; the electromagnetic spectrum and radiation theory; and how satellite radiometers "see" different sections of the spectrum. The module is part of an online course for grades 7-12 in satellite meteorology, which includes 10 interactive modules. The site also includes lesson plans developed by teachers and links to related resources. Each module is designed to serve as a stand-alone lesson, however, a sequential approach is recommended. Designed to challenge students through the end of 12th grade, middle school teachers and students may choose to skim or skip a few sections.

36

An opening electromagnetic transducer  

NASA Astrophysics Data System (ADS)

Tubular solenoids have been widely used without any change since an electrical wire was discovered to create magnetic fields by Hans Christian Oersted in 1820 and thereby the wire was first coiled as a helix into a solenoid coil by William Sturgeon in 1823 and was improved by Joseph Henry in 1829 [see http://www.myetymology.com/encyclopedia/History_of_the_electricity.html; J. M. D. Coey, Magnetism and Magnetic Materials (Cambridge University Press, New York, 2010); and F. Winterberg, Plasma Phys. 8, 541553 (1996)]. A magnetic control method of C-shaped carrying-current wire is proposed, and thereby a new opening electromagnetic transducer evidently differing from the traditional tubular solenoid is created, capable of directly encircling and centering the acted objects in it, bringing about convenient and innovative electromagnetic energy conversion for electromagnetic heating, electromagnetic excitation, physical information capture, and electro-mechanical motion used in science research, industry, and even biomedical activities.

Sun, Yanhua; Kang, Yihua

2013-12-01

37

Microslots : scalable electromagnetic instrumentation  

E-print Network

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 ...

Maguire, Yael G., 1975-

2004-01-01

38

Electromagnetism in the Movies.  

ERIC Educational Resources Information Center

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)

Everitt, Lori R.; Patterson, Evelyn T.

1999-01-01

39

Purely electromagnetic spacetimes  

E-print Network

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

B. V. Ivanov

2007-12-15

40

Concurrent electromagnetic scattering analysis  

NASA Technical Reports Server (NTRS)

The computational power of the hypercube parallel computing architecture is applied to the solution of large-scale electromagnetic scattering and radiation problems. Three analysis codes have been implemented. A Hypercube Electromagnetic Interactive Analysis Workstation was developed to aid in the design and analysis of metallic structures such as antennas and to facilitate the use of these analysis codes. The workstation provides a general user environment for specification of the structure to be analyzed and graphical representations of the results.

Patterson, Jean E.; Cwik, Tom; Ferraro, Robert D.; Jacobi, Nathan; Liewer, Paulett C.; Lockhart, Thomas G.; Lyzenga, Gregory A.; Parker, Jay

1989-01-01

41

Electromagnetic rotational actuation.  

SciTech Connect

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.

Hogan, Alexander Lee

2010-08-01

42

Electromagnetic attachment mechanism  

NASA Technical Reports Server (NTRS)

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.

Monford, Leo G., Jr. (inventor)

1992-01-01

43

Metamaterial electromagnetic wave absorbers.  

PubMed

The advent of negative index materials has spawned extensive research into metamaterials over the past decade. Metamaterials are attractive not only for their exotic electromagnetic properties, but also their promise for applications. A particular branch-the metamaterial perfect absorber (MPA)-has garnered interest due to the fact that it can achieve unity absorptivity of electromagnetic waves. Since its first experimental demonstration in 2008, the MPA has progressed significantly with designs shown across the electromagnetic spectrum, from microwave to optical. In this Progress Report we give an overview of the field and discuss a selection of examples and related applications. The ability of the MPA to exhibit extreme performance flexibility will be discussed and the theory underlying their operation and limitations will be established. Insight is given into what we can expect from this rapidly expanding field and future challenges will be addressed. PMID:22627995

Watts, Claire M; Liu, Xianliang; Padilla, Willie J

2012-06-19

44

Electromagnetic propulsion test facility  

NASA Technical Reports Server (NTRS)

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.

Gooder, S. T.

1984-01-01

45

Introducing electromagnetic field momentum  

NASA Astrophysics Data System (ADS)

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.

Yu-Kuang Hu, Ben

2012-07-01

46

Electromagnetic power absorber  

NASA Technical Reports Server (NTRS)

A structure is presented with a surface portion of dielectric material which passes electromagnetic radiation and with a portion below the surface which includes material that absorbs the radiation, the face of the structure being formed with numerous steep ridges. The steepness of the dielectric material results in a high proportion of the electromagnetic energy passing through the surface for absorption by the absorbing material under the surface. A backing of aluminum or other highly heat-conductive and reflective material lies under the face and has very steep protuberances supporting the absorbing and dielectric materials.

Iwasaki, R. S. (inventor)

1979-01-01

47

Electromagnetic environmental criteria for US Army missile systems: EMC (electromagnetic compatibility), EMR (electromagnetic radiation), EMI (electromagnetic interference), EMP (electromagnetic pulse), ESD (electrostatic discharge), and lightning  

NASA Astrophysics Data System (ADS)

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.

Ponds, C. D.

1985-01-01

48

Canceling Electromagnetic Interference During Tests  

NASA Technical Reports Server (NTRS)

Old technique solves modern problem. Simple amplitude-and-phase-cancellation technique removes strong electromagnetic interference from received test signal, enabling recovery of relatively weak signal from device under test. Useful in outdoor tests of devices for electromagnetic compatibility.

Robinson, Paul A., Jr.; Edmonds, Larry D.

1988-01-01

49

8.07 Electromagnetism II, Fall 2005  

E-print Network

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 ...

Bertschinger, Edmund

50

EMG #121471 Electromagnetics, 25:679693, 2005  

E-print Network

. Keywords electromagnetic compatibility, electromagnetic interference, aperture, cou- pling, finite compatibility (EMC) and electromagnetic interference (EMI) requirements, it is crucial to quantifyEMG #121471 Electromagnetics, 25:679­693, 2005 Copyright © 2005 Taylor & Francis Inc. ISSN: 0272

Ramahi, Omar

51

Electromagnetically Induced Flows Michiel de Reus  

E-print Network

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

Vuik, Kees

52

Electromagnetic propulsion for spacecraft  

Microsoft Academic Search

Three electromagnetic propulsion technologies, solid propellant pulsed plasma thrusters (PPT), magnetoplasmadynamic (MPD) thrusters, and pulsed inductive thrusters (PIT), were developed for application to auxiliary and primary spacecraft propulsion. Both the PPT and MPD thrusters were flown in space, though only PPT's were used on operational satellites. The performance of operational PPT's is quite poor, providing only approximately 8 percent efficiency

Roger M. Myers

1993-01-01

53

Electromagnetic conic sections  

Microsoft Academic Search

Certain orthogonal coordinate systems naturally correspond to basis vectors which are both curl-free and divergence-free, and hence solve Maxwell's equations. After first comparing several different traditional approaches to computing div, grad, and curl in curvilinear coordinates, we present a new approach, based on these ``electromagnetic'' basis vectors, which combines geometry and physics. Not only is our approach tied to a

Tevian Dray; Corinne A. Manogue

2002-01-01

54

Electromagnetic radiations from rocks  

Microsoft Academic Search

To test the possibility of the emission of electromagnetic waves from rocks, experiments have been made to measure the electric field by using mainly granite samples that were struck together or struck by a hammer or a weight and were fractured by a bending moment. The wide-band (10 Hz to 100 kHz) waveforms of electric signals were digitally recorded. Roughly

Toshio Ogawa; Kazuo Oike; Taiji Miura

1985-01-01

55

Physics 2000: Electromagnetic Waves  

NSDL National Science Digital Library

This website presents the physics of electromagnetic waves by describing the properties of waves, electric forces, force fields, and vibrating charges. Interactive animations and a question and answer "tutorial" format is used to present the information. Presentations about the applications of E&M waves are also included.

Goldman, Martin

2004-07-14

56

What Are Electromagnetic Fields?  

MedlinePLUS

... GHz. The effects of electromagnetic fields on the human body depend not only on their field level but on their frequency and energy. Our electricity power supply and all appliances using electricity are the main sources of ELF fields; computer screens, anti-theft devices and security systems are ...

57

Computation of Electromagnetic Fields  

Microsoft Academic Search

This paper reviews some of the more useful, current and newly developing methods for the solution of electromagnetic fields. It begins with an introduction to numerical methods in general, including specific references to the mathematical tools required for field analysis, e.g., solution of systems of simultaneous linear equations by direct and iterative means, the matrix eigenvalue problem, finite difference differentiation

A. Wexler

1969-01-01

58

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.

2011-08-29

59

Simple Superconducting "Permanent" Electromagnet  

NASA Technical Reports Server (NTRS)

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.

Israelson, Ulf E.; Strayer, Donald M.

1992-01-01

60

Noncontact Electromagnetic Vibration Source  

NASA Technical Reports Server (NTRS)

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.

Namkung, Min; Fulton, James P.; Wincheski, Buzz A.

1994-01-01

61

Equivalence principles and electromagnetism  

NASA Technical Reports Server (NTRS)

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

Ni, W.-T.

1977-01-01

62

Electromagnetic pulsar spindown  

E-print Network

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

I. Contopoulos

2007-01-10

63

Electromagnetism and Gravitation  

E-print Network

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

Kenneth Dalton

1995-12-12

64

The electromagnetic chemical propulsion concept  

Microsoft Academic Search

A new concept of propulsion to high velocities is presented. It combines the strong points of electrothermal chemical and electromagnetic methods. The projectile is accelerated by electromagnetic forces. Similar to other methods of electromagnetic propulsion, this overcomes the common limitations of conventional and electrothermal guns, caused by limited expansion speed of hot gases at acceptable temperatures. As with electrothermal chemical

Yuri A. Dreizin

1995-01-01

65

Spectroscopy Interaction of electromagnetic radiation  

E-print Network

Spectroscopy 691 Interaction of electromagnetic radiation with atoms or molecules #12;Bacteriorhodopsin: a light-driven proton pump 486 #12;Electromagnetic Radiation 692 harmonic wave (Maxwell): y;Spectroscopy 691 Interaction of electromagnetic radiation with atoms or molecules two processes: emission

Gerwert, Klaus

66

Computational Electronics and Electromagnetics  

SciTech Connect

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.

DeFord, J.F.

1993-03-01

67

Electromagnetic Environment of Grounding Systems  

NASA Astrophysics Data System (ADS)

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

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

68

Electromagnetic Polarizabilities of Mesons  

E-print Network

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.

Aleksejevs, A

2014-01-01

69

Electromagnetic Polarizabilities of Mesons  

E-print Network

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.

A. Aleksejevs; S. Barkanova

2014-10-25

70

Electromagnetic wave energy converter  

NASA Technical Reports Server (NTRS)

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.

Bailey, R. L. (inventor)

1973-01-01

71

Nonlinear gravito-electromagnetism  

NASA Astrophysics Data System (ADS)

There is a non-linear and covariant electromagnetic analogy for gravity, in which the full Bianchi identities are Maxwell-type equations for the free gravitational field, encoded in the Weyl tensor. This tensor gravito-electromagnetism is based on a covariant generalization of spatial vector algebra and calculus to spatial tensor fields, and includes all non-linear effects from the gravitational field and matter sources. The non-linear vacuum Bianchi equations are invariant under spatial duality rotation of the gravito-electric and gravito-magnetic tensor fields. The super-energy density and super-Poynting vector of the gravitational field are natural duality invariants, and satisfy a super-energy conservation equation.

Maartens, Roy

2008-06-01

72

Magnetism and Electromagnetism  

NSDL National Science Digital Library

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

Kuphaldt, Tony R.

2008-07-07

73

Electromagnetic propulsion of satellites  

Microsoft Academic Search

A propulsion system using the electromagnetic repulsion between two parallel conductors, carrying in opposite directions high currents, is considered. Very high projection velocities, above 70000m\\/s, are expected, corresponding with a thrust reaching 200000N. Such propulsion system can operate in pulsed conditions, throwing 10-6kg aluminium wires at a frequency of 10Hz. Then the average value of the thrust is 0.7N; so

Alexandre Pozwolski

2008-01-01

74

Banded electromagnetic stator core  

DOEpatents

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.

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

1996-06-11

75

Banded electromagnetic stator core  

DOEpatents

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.

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

1994-04-05

76

Banded electromagnetic stator core  

DOEpatents

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.

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

77

Banded electromagnetic stator core  

DOEpatents

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.

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

78

Ordinary electromagnetic mode instability  

NASA Technical Reports Server (NTRS)

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

Cheng, C. Z.

1974-01-01

79

Electromagnetic polarizabilities of hadrons  

SciTech Connect

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.

Friar, J.L.

1988-01-01

80

Electromagnetic tornadoes in space  

SciTech Connect

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.

Chang, T.; Crew, G.B.; Retterer, J.M.

1988-01-01

81

A Magic Electromagnetic Field  

E-print Network

An electromagnetic field of simple algebraic structure is simply derived. It turns out to be the G=0 limit of the charged rotating Kerr-Newman metrics. These all have gyromagnetic ratio 2, the same as the Dirac electron. The charge and current distributions giving this high gyromagnetic ratio have charges of both signs rotating at close to the velocity of light. It is conjectured that something similar may occur in the quantum electrodynamic charge distribution surrounding the point electron.

Donald Lynden-Bell

2002-07-02

82

Hyperphysics: Electromagnetic Waves  

NSDL National Science Digital Library

This Wikipedia page contains a labeled diagram of an electromagnetic wave showing how the electric and magnetic vectors change as a wave moves through space. Text introduces the physics of the wave. Just above the diagram is a map of related concepts, depicted as a network. This page is part of the HyperPhysics Collection, which contains many short, illustrated pages on various areas of physics and astronomy.

Nave, Carl R.

2012-03-25

83

Method of electromagnetic exploration  

SciTech Connect

A method is described of electromagnetic exploration comprising the following steps: obtaining measures of two horizontal components of the earth's magnetic field at each reference sites; obtaining a measure of the vertical component of the earth's magnetic field for at least one exploratory site; and determining a measure of a multidimensional earth resistivity structure by correlating the measures of horizontal and vertical components of the earth's magnetic field.

Nekut, A.G. Jr.

1987-05-05

84

The KLOE electromagnetic calorimeter  

NASA Astrophysics Data System (ADS)

The KLOE calorimeter is a fine lead-scintillating fiber sampling calorimeter. We describe in the following the calibration procedures and the calorimeter performances obtained after 3 years of data taking. We get an energy resolution for electromagnetic showers of 5.4%/ E (GeV) and a time resolution of 56 ps/ E (GeV). We also present a measurement of efficiency for low-energy photons.

Adinolfi, M.; Ambrosino, F.; Antonelli, A.; Antonelli, M.; Anulli, F.; Barbiellini, G.; Bencivenni, G.; Bertolucci, S.; Bini, C.; Bloise, C.; Bocci, V.; Bossi, F.; Branchini, P.; Cabibbo, G.; Caloi, R.; Campana, P.; Casarsa, M.; Cataldi, G.; Ceradini, F.; Cervelli, F.; Ciambrone, P.; De Lucia, E.; De Simone, P.; De Zorzi, G.; Dell'Agnello, S.; Denig, A.; Di Domenico, A.; Di Donato, C.; Di Falco, S.; Doria, A.; Erriquez, O.; Farilla, A.; Ferrari, A.; Ferrer, M. L.; Finocchiaro, G.; Forti, C.; Franceschi, A.; Franzini, P.; Gao, M. L.; Gatti, C.; Gauzzi, P.; Giannasi, A.; Giovannella, S.; Graziani, E.; Han, H. G.; Han, S. W.; Huang, X.; Incagli, M.; Ingrosso, L.; Keeble, L.; Kim, W.; Kuo, C.; Lanfranchi, G.; Lee-Franzini, J.; Lomtadze, T.; Mao, C. S.; Martemianov, M.; Mei, W.; Messi, R.; Miscetti, S.; Moccia, S.; Moulson, M.; Mller, S.; Murtas, F.; Pacciani, L.; Palomba, M.; Palutan, M.; Pasqualucci, E.; Passalacqua, L.; Passeri, A.; Picca, D.; Pirozzi, G.; Pontecorvo, L.; Primavera, M.; Santangelo, P.; Santovetti, E.; Saracino, G.; Schamberger, R. D.; Sciascia, B.; Scuri, F.; Sfiligoi, I.; Silano, P.; Spadaro, T.; Spiriti, E.; Tortora, L.; Valente, P.; Valeriani, B.; Venanzoni, G.; Ventura, A.; Wlfle, S.; Wu, Y.; Xie, Y. G.; Zema, P. F.; Zhang, C. D.; Zhang, J. Q.; Zhao, P. P.

2002-11-01

85

Flash memory electromagnetic compatibility  

Microsoft Academic Search

This paper analyzes the radiated electromagnetic compatibility (EMC) behavior of AMD\\/Spansion Flash memory integrated circuits. Using The Engineering Society For Advanced Mobility Land Sea Air and Space (SAE) J1752\\/3 method, the peak RF noise (EMC with respect to radiated emissions) was measured for various technologies and product features, determining statistically valid sensitivity factors for several independent variables. The findings show

Adam D. Fogle; Don Darling; Richard C. Blish; Gene Daszko

2006-01-01

86

Fractional Electromagnetic Waves  

E-print Network

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

J. F. Gmez; J. J. Rosales; J. J. Bernal; V. I. Tkach; M. Gua

2011-08-31

87

Quaternion Gravi-Electromagnetism  

E-print Network

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.

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

2011-07-05

88

Gravitation and Electromagnetism  

E-print Network

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

B. G. Sidharth

2001-06-16

89

Gravito-electromagnetic analogies  

NASA Astrophysics Data System (ADS)

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.

Costa, L. Filipe O.; Natrio, Jos

2014-10-01

90

Ejs Electromagnetic Wave Model  

NSDL National Science Digital Library

The Ejs Electromagnetic Wave model displays the electric field of an electromagnetic wave. The simulation allows an arbitrarily polarized wave to be created. The magnitude of the electric field components and the relative phase between the components of the electric field can all be changed via sliders. You can modify this simulation if you have Ejs installed by right-clicking within the plot and selecting Open Ejs Model from the pop-up menu item. Ejs Electromagnetic Wave model was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_ehu_waves_emwave.jar file will run the program if Java is installed. Ejs is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional Ejs models for wave optics are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs.

Aguirregabiria, Juan

2008-08-20

91

Electromagnetic Radiations Emanating From A Quenched Superconducting Electromagnet  

Microsoft Academic Search

A qualitative discussion is presented on the subject of electromagnetic radiations emanating from an arc discharge which is the result of an accidentally quenched superconducting electromagnet. The discussion is based upon the assumption that the electromagnet is the B-field source of a sea-going vessels magnetohydrodynamic, MHD. power plant. Should such a vessel be one which operates subsurface, it then seems

S. A. Marshall; D. G. Yerg

1990-01-01

92

Electromagnetic Meissner-Effect Launcher  

NASA Technical Reports Server (NTRS)

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.

Robertson, Glen A.

1990-01-01

93

Electromagnetic field and cosmic censorship  

E-print Network

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.

Koray Dzta?

2013-12-27

94

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

E-print Network

-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 of electromagnetic environment in wireless networks affecting its intra- network electromagnetic compatibility

Loyka, Sergey

95

IEEE TRANSACTIONS ON ELECTROMAGNETIC COMPATIBILITY, VOL. 55, NO. 2, APRIL 2013 395 Electromagnetic Interference Analysis of  

E-print Network

IEEE TRANSACTIONS ON ELECTROMAGNETIC COMPATIBILITY, VOL. 55, NO. 2, APRIL 2013 395 Electromagnetic to electromagnetic interference (EMI) is becoming a critical aspect of signal integrity analysis. For mod- eling, delay, electromagnetic in- terference (EMI), incident fields, longitudinal partitioning, tran- sient

Roy, Sourajeet

96

Electromagnetically controllable osteoclast activity.  

PubMed

The time-varying electromagnetic field (EMF) has been widely studied as one of the exogenous stimulation methods for improving bone healing. Our previous study showed that osteogenic differentiation of adipose-derived stem cells was accelerated by a 45-Hz EMF, whereas a 7.5-Hz EMF inhibited osteogenic marker expression. Accordingly, we hypothesized that each negative and positive condition for the osteogenic differentiation could inversely influence osteoclast formation and differentiation. Here, we demonstrated that osteoclast formation, differentiation, and activity can be regulated by altering the frequency of the electromagnetic stimulation, such as 7.5 (negative for osteogenic differentiation) and 45 Hz (positive for osteogenic differentiation). A 45 Hz EMF inhibited osteoclast formation whereas a 7.5-Hz EMF induced differentiation and activity. Osteoclastogenic markers, such as NFATc1, TRAP, CTSK, MMP9, and DC-STAMP were highly expressed under the 7.5-Hz EMF, while they were decreased at 45 Hz. We found that the 7.5-Hz EMF directly regulated osteoclast differentiation through ERK and p38 MAPK activation, whereas the EMF at 45 Hz suppressed RANKL-induced phosphorylation of I?B. Additionally, actin ring formation with tubules and bone resorptive activity were enhanced at 7.5 Hz through increased integrin ?3 expression. However, these were inhibited at 45 Hz. Although many questions remain unanswered, our study indicates that osteoclast formation and differentiation were controllable using physical tools, such as an EMF. It will now be of great interest to study the ill-defined correlation between electromagnetic conditions and osteoclast activities, which eventually could lead to determining the therapeutic characteristics of an EMF that will treat bone-related diseases. PMID:24556539

Hong, Jung Min; Kang, Kyung Shin; Yi, Hee-Gyeong; Kim, Shin-Yoon; Cho, Dong-Woo

2014-05-01

97

Electromagnetism on Anisotropic Fractals  

E-print Network

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.

Martin Ostoja-Starzewski

2011-06-08

98

Electromagnetic Meissner effect launcher  

NASA Technical Reports Server (NTRS)

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.

Robertson, Glen A. (inventor)

1991-01-01

99

Electromagnetic pump stator coil  

SciTech Connect

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.

Fanning, Alan W. (San Jose, CA); Dahl, Leslie R. (Livermore, CA)

1996-01-01

100

Electromagnetic pump stator coil  

DOEpatents

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.

Fanning, A.W.; Dahl, L.R.

1996-06-25

101

Electromagnetic Processes in ?EFT  

NASA Astrophysics Data System (ADS)

Nuclear electromagnetic currents derived in a chiral-effective-field-theory framework including explicit nucleons, ? isobars, and pions up to N2LO, i.e. ignoring loop corrections, are used in a study of neutron radiative captures on protons and deuterons at thermal energies, and of A=2 and 3 nuclei magnetic moments. With the strengths of the ?-excitation currents determined to reproduce the n-p cross section and isovector combination of the trinucleon magnetic moments, we find that the cross section and photon circular polarization parameter, measured respectively in n-d and /rightarrow n - d processes, are significantly underpredicted by theory.

Pastore, S.; Schiavilla, R.; Goity, J. L.

102

Electromagnetic Probes in PHENIX  

E-print Network

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

Gabor David

2006-09-21

103

Electromagnetic Processes in $?$EFT  

E-print Network

Nuclear electromagnetic currents derived in a chiral-effective-field-theory framework including explicit nucleons, $\\Delta$ isobars, and pions up to N$^2$LO, {\\it i.e.} ignoring loop corrections, are used in a study of neutron radiative captures on protons and deuterons at thermal energies, and of $A$=2 and 3 nuclei magnetic moments. With the strengths of the $\\Delta$-excitation currents determined to reproduce the $n$-$p$ cross section and isovector combination of the trinucleon magnetic moments, we find that the cross section and photon circular polarization parameter, measured respectively in $n$-$d$ and $\\vec{n}$-$d$ processes, are significantly underpredicted by theory.

S. Pastore; R. Schiavilla; J. L. Goity

2008-09-15

104

Gravitation and electromagnetism  

E-print Network

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

V. P. Dmitriyev

2002-07-23

105

Electromagnetic Neutrino Properties and Neutrino Oscillations in Electromagnetic Fields  

E-print Network

The presence of medium and external magnetic field change electromagnetic properties of neutrino. In this article the behavior of neutrino magnetic moment in electromagnetic field is considered. On the basis the Bargmann-Michel-Telegdi equation for the case of models with CP invariance and P nonconservation the new type of neutrino resonances $\

A. M. Egorov; A. E. Lobanov; A. I. Studenikin

1999-02-23

106

Electromagnetic Field Penetration Studies  

NASA Technical Reports Server (NTRS)

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.

Deshpande, M.D.

2000-01-01

107

Electromagnetic interaction of metamaterials  

NASA Astrophysics Data System (ADS)

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

Canales, Peter R.

108

Interactions between electromagnetic fields  

NASA Astrophysics Data System (ADS)

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.

Schwan, H. P.

1985-02-01

109

Structural composites with integrated electromagnetic functionality  

E-print Network

Structural composites with integrated electromagnetic functionality Syrus C. Nemat-Nasser, Alireza structural functionality. This integration of both electromagnetic and structural functionality throughout. INTRODUCTION Our work on multifunctional structural composites targets the integration of electromagnetic

Nemat-Nasser, Sia

110

Localization of Classical Waves II: Electromagnetic Waves.  

E-print Network

Localization of Classical Waves II: Electromagnetic Waves. Alexander Figotin \\Lambda Department We consider electromagnetic waves in a medium described by a position dependent dielectric constant at all times. Localization of electromagnetic waves is a consequence of Anderson localization

111

Transmitting Electromagnetic Energy into Liquids  

NASA Technical Reports Server (NTRS)

Rough liquid surface enhances coupling. Agitating surface of liquid nitrogen bath with periodic or aperiodic excitation enhances electromagnetic coupling between microwave horn and blackbody temperature standard immersed in liquid. Useful in interfaces between electromagnetic radiation and liquids. Biomedical, radar, and meteorological applications.

Johnston, E. J.

1984-01-01

112

Electromagnetic Navigation during Flexible Bronchoscopy  

Microsoft Academic Search

Background: Flexible bronchoscopy is routinely utilized in the diagnosis and treatment of various lung diseases. Nondiagnostic bronchoscopy leads to more invasive interventions, such as transthoracic needle aspiration, mediastinoscopy or even thoracotomy. Electromagnetic navigation is a novel technology that facilitates approaching peripheral lung lesions, which are difficult to sample by conventional means. The navigation system involves creating an electromagnetic field around

Yehuda Schwarz; Atul C. Mehta; Armin Ernst; Felix Herth; Ahuva Engel; Doron Besser; Heinrich D. Becker

2003-01-01

113

The Electromagnetic Spectrum: Infrared Waves  

NSDL National Science Digital Library

This webpage, part of a NASA site on the electromagnetic spectrum, presents information on infrared light. An explanation of how objects emit infrared is provided, along with a diagram of the electromagnetic spectrum. The site contains a number of photos made with infrared light.

2007-06-24

114

On quantization of electromagnetic field  

E-print Network

These are six papers joined by the same title. The main topics are: 1. algebraic nature of quantization of relativistic fields, 2. constructive definition of space of states of quantum electromagnetic field, 3. structure of space of states of quantum electromagnetic field from functional analysis standpoint.

D. A. Arbatsky

2004-02-04

115

NISTHB 150-11 Electromagnetic  

E-print Network

NISTHB 150-11 NVLAP Electromagnetic Compatibility and Telecommunications Bethany Hackett Bradley Moore Dennis Camell http://dx.doi.org/10.6028/NIST.HB.150-11 #12;NISTHB 150-11 NVLAP Electromagnetic Compatibility and Telecommunications Bethany Hackett Bradley Moore National Voluntary Laboratory Accreditation

Perkins, Richard A.

116

Exploration of the Electromagnetic Environment  

ERIC Educational Resources Information Center

The electromagnetic environment is composed of electric and magnetic fields which result from man-made and natural sources. An elementary experiment is described to explore the electromagnetic environment by measuring electric fields in the frequency range from approximately equal to 10 to 24 000 Hz. The equipment required to conduct the

Fullekrug, M.

2009-01-01

117

Particle swarm optimization in electromagnetics  

Microsoft Academic Search

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

Jacob Robinson; Yahya Rahmat-Samii

2004-01-01

118

Gravitational scattering of electromagnetic radiation  

NASA Technical Reports Server (NTRS)

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.

Brooker, J. T.; Janis, A. I.

1980-01-01

119

Electromagnetic reactions on light nuclei  

E-print Network

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

Bacca, Sonia

2014-01-01

120

Electromagnetic propulsion for spacecraft  

NASA Technical Reports Server (NTRS)

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.

Myers, Roger M.

1993-01-01

121

The Electromagnetic Spectrum  

NSDL National Science Digital Library

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

122

Nanofocusing of electromagnetic radiation  

NASA Astrophysics Data System (ADS)

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.

Gramotnev, Dmitri K.; Bozhevolnyi, Sergey I.

2014-01-01

123

Wavelets and electromagnetics  

NASA Technical Reports Server (NTRS)

Wavelets are an exciting new topic in applied mathematics and signal processing. This paper will provide a brief review of wavelets which are also known as families of functions with an emphasis on interpretation rather than rigor. We will derive an indirect use of wavelets for the solution of integral equations based techniques adapted from image processing. Examples for resistive strips will be given illustrating the effect of these techniques as well as their promise in reducing dramatically the requirement in order to solve an integral equation for large bodies. We also will present a direct implementation of wavelets to solve an integral equation. Both methods suggest future research topics and may hold promise for a variety of uses in computational electromagnetics.

Kempel, Leo C.

1992-01-01

124

Electromagnetically Clean Solar Arrays  

NASA Technical Reports Server (NTRS)

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.

Stem, Theodore G.; Kenniston, Anthony E.

2008-01-01

125

Pulsed electromagnetic gas acceleration  

NASA Technical Reports Server (NTRS)

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

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

1971-01-01

126

Causal electromagnetic interaction equations  

SciTech Connect

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

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

2011-02-15

127

Adjoint charge in electromagnetic field  

E-print Network

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.

Zi-Hua Weng

2009-10-07

128

Gravitational mass in electromagnetic field  

E-print Network

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.

Zihua Weng

2008-07-28

129

ELECTROMAGNETIC FIELD EFFECTS IN EXPLOSIVES  

SciTech Connect

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

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

2009-12-28

130

PHYSICS 417. Electromagnetism. Lecturer: Tim Gorringe.  

E-print Network

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

MacAdam, Keith

131

Kinetic Equation with Electromagnetic Interactions.  

National Technical Information Service (NTIS)

A kinetic equation for a plasma with electromagnetic interactions is derived in the shielding approximation. The equation is the analog of the Landau equation and has the same structure as the Landau equation but with a velocity dependent interaction repl...

J. T. Hogan, M. B. Lewis

1967-01-01

132

Electromagnetic Signals from Bacterial DNA  

E-print Network

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

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

2011-04-15

133

Conical electromagnetic radiation flux concentrator  

NASA Technical Reports Server (NTRS)

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.

Miller, E. R.

1972-01-01

134

Electromagnetic Dissociation and Space Radiation  

E-print Network

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.

John W. Norbury; Khin Maung Maung

2006-12-08

135

Electromagnetic recording and playback device  

E-print Network

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

Chavez, Dylan, 1981-

2004-01-01

136

Electromagnetic Effects in SDF Explosions  

Microsoft Academic Search

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

H Reichenbach; P Neuwald; A L Kuhl

2010-01-01

137

Electromagnetic Spectrum from QGP Fluid  

E-print Network

We calculate thermal photon and electron pair distribution from hot QCD matter produced in high energy heavy-ion collisions, based on a hydrodynamical model which is so tuned as to reproduce the recent experimental data at CERN SPS, and compare these electromagnetic spectra with experimental data given by CERN WA80 and CERES. We investigate mainly the effects of the off-shell properties of the source particles on the electromagnetic spectra.

T. Hirano; S. Muroya; M. Namiki

1997-08-29

138

The Nature of Electromagnetic Radiation  

NSDL National Science Digital Library

This web site is a reference page on electromagnetic radiation. It discusses the spectrum of light and both the wave and quantum nature of radiation. Also included are descriptions of the physics and applications of the different frequency bands, from gamma rays through radio waves, plus links to interactive Java simulations on the topic. See Related Materials on this page for a simpler student tutorial by the same authors on the topic of electromagnetic radiation.

Davidson, Michael; Abramowitz, Mortimer; Fellers, Thomas J.

2008-08-21

139

Time Reversal of Electromagnetic Waves  

Microsoft Academic Search

We report the first experimental demonstration of time-reversal focusing with electromagnetic waves. An antenna transmits a 1-mus electromagnetic pulse at a central frequency of 2.45GHz in a high-Q cavity. Another antenna records the strongly reverberated signal. The time-reversed wave is built and transmitted back by the same antenna acting now as a time-reversal mirror. The wave is found to converge

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

2004-01-01

140

Black Hole Thermodynamics and Electromagnetism  

E-print Network

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

Burra G. Sidharth

2005-07-15

141

Electromagnetic Calorimeter for HADES  

E-print Network

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

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

2011-09-26

142

From GEM to electromagnetism  

NASA Astrophysics Data System (ADS)

In the first part of the present work, we focus on the theory of gravitoelectromagnetism (GEM), and we derive the full set of equations and constraints that the GEM scalar and vector potentials ought to satisfy. We discuss important aspects of the theory, such as the presence of additional constraints resulting from the field equations and gauge condition, the requirement of the time-independence of the vector potential and the emergence of additional terms in the expression of the Lorentz force. We also propose an alternative ansatz for the metric perturbations that is found to be compatible only with a vacuum configuration but evades several of the aforementioned obstacles. In the second part of this work, we pose the question of whether a tensorial theory using the formalism of General Relativity could re-produce the theory of Electromagnetism. We demonstrate that the full set of Maxwell's equations can be exactly re-produced for a large class of models, but the framework has several weak points common with those found in GEM.

Bakopoulos, A.; Kanti, P.

2014-06-01

143

Electromagnetism of Bacterial Growth  

NASA Astrophysics Data System (ADS)

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.

Ainiwaer, Ailiyasi

2011-10-01

144

Electromagnetic Launch to Space  

NASA Astrophysics Data System (ADS)

Many advances in electromagnetic (EM) propulsion technology have occurred in recent years. Linear motor technology for low-velocity and high-mass applications is being developed for naval catapults. Such technology could serve as the basis for a first-stage booster launch--as suggested by the US National Aeronautics and Space Administration (NASA) in the Maglifter concept. Using railguns, laboratory experiments have demonstrated launch velocities of 2-3 km/s and muzzle energies > 8 MJ. The extension of this technology to the muzzle velocities ( 7500 m/s) and energies ( 10 GJ) needed for the direct launch of payloads into orbit is very challenging but may not be impossible. For launch to orbit, even long launchers (> 1000 m) would need to operate at accelerations > 1000 G to reach the required velocities, so it would only be possible to launch rugged payloads, such as fuel, water, and materiel. Interest is being shown in such concepts by US, European, Russian, and Chinese researchers. An intermediate step proposed in France could be to launch payloads to sounding rocket altitudes for ionospheric research.

McNab, I. R.

145

SOLAR NANTENNA ELECTROMAGNETIC COLLECTORS  

SciTech Connect

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

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

2008-08-01

146

Polarimetry of electromagnetic materials  

NASA Astrophysics Data System (ADS)

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.

Asahi, Toru; Osaka, Tetsuya; Kobayashi, Jinzo

2001-07-01

147

Electromagnetic Navigational Bronchoscopy  

PubMed Central

Despite advances in technology and treatment options, lung cancer remains a deadly disease. National screening programs are being instituted in an attempt to discover lung cancer in high-risk individuals at an earlier stage. Such screening programs invariably discover small peripheral nodules that previously would not have been clinically apparent; the management of such lesions can be challenging. Current diagnostic options such as percutaneous biopsy are effective; however, they are hindered by their risk of morbidity such as pneumothorax. Electromagnetic bronchoscopy (ENB) is an emerging technology that allows the practitioner the ability to both sample and treat small peripheral pulmonary lesions. In experienced centers, ENB provides high rates of diagnostic yield for small lesions and a complication rate significantly lower than that of more conventional diagnostic modalities. Although there are current barriers to its widespread utilization (cost, specialized imaging, technical training), these obstacles will handled similarly to any other emerging technology and will likely not be long-term impediments to its use. PMID:24436528

Port, Jeffrey; Harrison, Sebron

2013-01-01

148

Electromagnetically driven peristaltic pump  

DOEpatents

An electromagnetic peristaltic pump apparatus may comprise a main body section having an inlet end and an outlet end and a flexible membrane which divides the main body section into a first cavity and a second cavity. The first cavity is in fluid communication with the inlet and outlet ends of the main body section. The second cavity is not in fluid communication with the first cavity and contains an electrically conductive fluid. The second cavity includes a plurality of electrodes which are positioned within the second cavity generally adjacent the flexible membrane. A magnetic field generator produces a magnetic field having a plurality of flux lines at least some of which are contained within the second cavity of the main body section and which are oriented generally parallel to a flow direction in which a material flows between the inlet and outlet ends of the main body section. A control system selectively places a voltage potential across selected ones of the plurality of electrodes to deflect the flexible membrane in a wave-like manner to move material contained in the first cavity between the inlet and outlet ends of the main body section.

Marshall, Douglas W. (Blackfoot, ID)

2000-01-01

149

Pulsed electromagnetic gas acceleration  

NASA Technical Reports Server (NTRS)

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.

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

1974-01-01

150

Electromagnetic compatibility in semiconductor manufacturing  

SciTech Connect

Electromagnetic Interference (EMI) causes problems in semiconductor manufacturing facilities that range from nuisances to major disruptions of production. In many instances, these issues are addressed in a reactionary rather than proactive manner by individuals who do not have the experience or the equipment necessary to combat EMI problems in a timely, cost effective manner. This approach leads to expensive retrofits, reduced equipment availability, long recovery times, and in some cases, line yield impacts. The goal of electromagnetic compatibility (EMC) in semiconductor manufacturing is to ensure that semiconductor process, metrology, and support equipment operate as intended without being affected by electromagnetic disturbances either transmitted through air (radiated interference), or transferred into the equipment via a conductive media (conducted interference). Rather than being neglected until serious issues arise, EMC should be considered in the early stages of facility design, in order to gain the most benefit at the lowest cost.

Montoya, J.A. [Intel Corp., Hillsboro, OR (United States)

1995-12-31

151

Dipole-Induced Electromagnetic Transparency  

NASA Astrophysics Data System (ADS)

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.

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

2014-10-01

152

Dipole-induced electromagnetic transparency.  

PubMed

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

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

2014-10-17

153

Un-renormalized classical electromagnetism  

SciTech Connect

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

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

2006-02-15

154

Electromagnetic Models of Extragalactic Jets  

NASA Astrophysics Data System (ADS)

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

Lisanti, M.; Blandford, R.

2007-07-01

155

Gauge invariant fractional electromagnetic fields  

NASA Astrophysics Data System (ADS)

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.

Lazo, Matheus Jatkoske

2011-09-01

156

Introduction to The Electromagnetic Spectrum  

NSDL National Science Digital Library

This NASA-created web site introduces electromagnetic waves and their behaviors to secondary learners. Each region of the spectrum is described, illustrated, and accompanied by video clips. Within each section, the authors explore the relationship between wavelength and wave type and provide information about how scientists detect the various waves and collect images of their emissions. Don't miss the link to NASA's Tour of the Electromagnetic Spectrum, a free set of 24 posters, which can be viewed online or printed for the classroom. This tutorial is part of NASA's Mission: Science website.

2009-10-05

157

Electromagnetic computations for fusion devices  

SciTech Connect

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.

Turner, L.R.

1989-09-01

158

Holographic Estimate of Electromagnetic Mass  

E-print Network

Using the gauge/gravity duality, we calculate the electromagnetic contributions to hadron masses, where mass generates dynamically by strong QCD interactions. Based on the Sakai-Sugimoto model of holographic QCD we find that the electromagnetic mass of proton is 0.48 MeV larger than that of neutron, which is in agreement with recent lattice results. Similarly for pions we obtain $m_{\\pi^{\\pm}}-m_{\\pi^0}$=4.1 ~ 5.4 MeV, close to the experimental value.

Hong, Deog Ki

2014-01-01

159

Electromagnetic Models of Extragalactic Jets  

SciTech Connect

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

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

2007-10-22

160

Electromagnetic radiation by gravitating bodies  

E-print Network

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

Iwo Bialynicki-Birula; Zofia Bialynicka-Birula

2008-04-06

161

Electromagnetic control of coupled droplets  

NASA Astrophysics Data System (ADS)

Electromagnetism offers several advantages for moving capillary surfaces, including energy efficiency, fast response, and device integrability. Here, we demonstrate electromagnetic control of a pinned-contact, coupled droplet system using aqueous ferrofluids. A time-varying magnetic field provides the necessary perturbation to toggle millimeter scale capillary switches. Furthermore, periodic magnetic fields can drive coupled droplets at resonant frequencies approaching 100 Hz using only 1 V by balancing capillary forces with liquid inertia. These addressable devices may find applications in adaptive optics, fluidic actuators, and read-write arrays.

Malouin, Bernard A.; Vogel, Michael J.; Hirsa, Amir H.

2010-05-01

162

Bathymetry, electromagnetic streamlines and the marine controlled source electromagnetic method  

NASA Astrophysics Data System (ADS)

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.

Pethick, Andrew 12Harris, Brett

2014-07-01

163

Electromagnetic formation flight dipole solution planning  

E-print Network

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 ...

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

2005-01-01

164

Visible Light and the Electromagnetic Spectrum  

NSDL National Science Digital Library

During this lesson, the electromagnetic spectrum is explained and students learn that visible light makes up only a portion of this wide spectrum. Students also learn that engineers use electromagnetic waves for many different applications.

Integrated Teaching And Learning Program

165

Quantized electromagnetic tornado in pulsar vacuum gap  

E-print Network

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

Fominov, Yakov

166

Electromagnetically Restrained Lithium Blanket APEX Interim Report November, 1999  

E-print Network

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

California at Los Angeles, University of

167

The electromagnetic spectrum : waves of energy  

NSDL National Science Digital Library

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.

Coulson, Tracy; Kennedy, Karen

2002-01-01

168

Electromagnetic effects on geodesic acoustic modes  

NASA Astrophysics Data System (ADS)

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.

Bashir, M. F.; Smolyakov, A. I.; Elfimov, A. G.; Melnikov, A. V.; Murtaza, G.

2014-08-01

169

3D Electromagnetic Field Analysis for Mixing Suspension Electromagnet Used by Maglev Train  

Microsoft Academic Search

A maglev train is supported by electromagnetic force between suspension electromagnet and track and is driven by linear motor. The suspension electromagnet is an important part of a maglev train. Its operating characteristic has a direct bearing on technology-economy performance and run safety of the whole train. The paper advances a new electromagnet structure mixing permanent magnet with electric excitation

Liu Shaoke; Guo Zhongjun; Chen Guirong

2010-01-01

170

STIMULATED ELECTROMAGNETIC EMISSIONS BY HIGH-FREQUENCY ELECTROMAGNETIC PUMPING OF THE  

E-print Network

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

171

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

E-print Network

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

Taflove, Allen

172

Pulsed power for electromagnetic launching  

Microsoft Academic Search

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

M. Cowan

1982-01-01

173

Electromagnetic generators for power harvesting  

Microsoft Academic Search

The design of electromagnetic generators that can be integrated within shoe soles is described. In this way, parasitic energy expended by a person when walking can be tapped and used to power portable electronic equipment. Designs are based on discrete permanent magnets and copper wire coils, and it is intended to improve performance by applying micro-fabrication technologies. Detailed descriptions of

M. Duffy; D. Carroll

2004-01-01

174

Inertia, Electromagnetism and Fluid Dynamics  

Microsoft Academic Search

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

Alexandre A. Martins; Mario J. Pinheiro

2008-01-01

175

Proposed electromagnetic wave energy converter  

NASA Technical Reports Server (NTRS)

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.

Bailey, R. L.

1973-01-01

176

The theory of electromagnetic levitation  

Microsoft Academic Search

Identifies a number of fundamental principles of physics which are involved in applying electromagnetic suspensions to transport. The theory relating to these is developed and typical values are given for important variables and parameters when an overall view of the transport system is taken. A number of simplifications and assumptions are used in order to treat as concisely as possible

R. Goodall

1985-01-01

177

Power electronics and electromagnetic compatibility  

Microsoft Academic Search

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

R. Redl

1996-01-01

178

Finite formulation of electromagnetic field  

Microsoft Academic Search

We show that the equations of electromagnetism can be directly obtained in a finite form, i.e., discrete, thus avoiding the traditional discretization methods of Maxwell's differential equations. The finite formulation can be used with unstructured meshes in two and three dimensions and easily permits to obtain fourth-order convergence

Enzo Tonti; Piazzale Europa

2002-01-01

179

Explanations, Education, and Electromagnetic Fields.  

ERIC Educational Resources Information Center

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

Friedman, Sharon M.

180

The Electromagnetic Spectrum: Resonating Atmosphere  

NSDL National Science Digital Library

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

181

Electromagnetic test facilities at Sandia National Laboratories  

Microsoft Academic Search

The paper describes major electromagnetic test facilities at Sandia National Laboratories; each has undergone recent upgrades. The paper discusses each facility, their uses, and upgrades pertaining to the facilities performance and diagnostic capabilities. The facilities discussed are the Sandia lightning simulator, the electromagnetic environments simulator (a large TEM cell), the mode-stirred chamber, and the anechoic chamber. Sandia's expertise in electromagnetics

Michele Caldwell; Matthew B. Higgins

2005-01-01

182

EE4391A Electromagnetic Compatibility Summer 2004  

E-print Network

EE4391A Electromagnetic Compatibility Summer 2004 Instructor: Dr. W. Marshall Leach, Jr., Van Leer compatibility and the agencies which write these regulations. To examine the electromagnetic properties on electromagnetic compatibility. To examine the benefits of using balanced signals and the methods of power supply

Leach Jr.,W. Marshall

183

CONDUCTED EMISSIONS TESTING FOR ELECTROMAGNETIC COMPATIBILITY  

E-print Network

CONDUCTED EMISSIONS TESTING FOR ELECTROMAGNETIC COMPATIBILITY Maximilian Moy Lockheed Martin, 1801 range is creating an increased need for electromagnetic compatibility (EMC) testing. In the United.4-2001 [2] was the primary guide used for the design of the system. Electromagnetic compatibility references

Arakaki, Dean Y.

184

Electromagnetic driving units for complex microrobotic systems  

Microsoft Academic Search

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

Frank Michel; Wolfgang Ehrfeld; Udo Berg; Reinhard Degen; Felix Schmitz

1998-01-01

185

Numerical Analysis of Conducted Electromagnetic Interferences  

Microsoft Academic Search

AbstractThe split of the ,conducted Electromagnetic Interference noises into different modes, common and differential mode is important to the conducted Electromagnetic Interference modeling and appropriate application of mitigation techniques. A method of Electromagnetic Interference noise decomposition is based on algebraic calculations and the Fourier transform. The method can be useful in comparative analysis of the influence of inverter control algorithms

Eleonora Darie; Emanuel Darie

2008-01-01

186

Some Student Conceptions of Electromagnetic Induction  

ERIC Educational Resources Information Center

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

Thong, Wai Meng; Gunstone, Richard

2008-01-01

187

A technology that squeezes electromagnetic waves  

E-print Network

A technology that squeezes electromagnetic waves into minuscule structures may yield a new and manipulate visible light and other electromagnetic waves--could someday replace electronic circuits in micro plasmons with the same frequency as the outside electromagnetic waves but with a much shorter wavelength

Atwater, Harry

188

ABSORBING BOUNDARY CONDITIONS FOR ELECTROMAGNETIC WAVE PROPAGATION  

E-print Network

ABSORBING BOUNDARY CONDITIONS FOR ELECTROMAGNETIC WAVE PROPAGATION Xiaobing Feng y Abstract of the electromagnetic fields indi­ vidually. This boundary condition allows any wave motion generated within the domain, and the electromagnetic wave scattering related to antennas. Because of the limitations of both speed and memory

189

Acousto-electromagnetic Tomography Habib Ammari  

E-print Network

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

Garnier, Josselin

190

Electromagnetic Corrections in Staggered Chiral Perturbation Theory  

E-print Network

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

Bernard, Claude

191

PERFECT ELECTROMAGNETIC CONDUCTOR (PEMC) AND FRACTIONAL WAVEGUIDE  

Microsoft Academic Search

Fractional curl operator has been utilized to study the fractional perfect electromagnetic conducting waveguide. The fractional perfect electromagnetic conducting waveguide may be regarded as intermediate step between the two given waveguides. One of the waveguide is composed of perfect electromagnetic conducting (PEMC) walls while other is dual of it as (DPEMC). Corresponding fields and surface impedance have been determined and

Akhtar Hussain; Qaisar A. Naqvi

2007-01-01

192

611: Electromagnetic Theory Problem Sheet 5  

E-print Network

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

Pope, Christopher

193

Course Outline Physics 433: Electromagnetism II  

E-print Network

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

194

611: Electromagnetic Theory Problem Sheet 5  

E-print Network

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

Pope, Christopher

195

Electromagnetic Interrogation of Dielectric Materials 1  

E-print Network

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

196

611: Electromagnetic Theory Problem Sheet 5  

E-print Network

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

Pope, Christopher

197

611: Electromagnetic Theory Problem Sheet 6  

E-print Network

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

Pope, Christopher

198

Electromagnetic Formation Flight of Satellite Arrays  

E-print Network

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

199

Physics 4: Introductory Physics Electromagnetism and Light  

E-print Network

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

Fygenson, Deborah Kuchnir

200

Strong permanent magnet-assisted electromagnetic undulator  

DOEpatents

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.

Halbach, Klaus (Berkeley, CA)

1988-01-01

201

Some Wave Equations for Electromagnetism and Gravitation  

E-print Network

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

Zi-Hua Weng

2010-08-11

202

Electromagnetic Activation of Capillary Switches  

NASA Astrophysics Data System (ADS)

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.

Malouin, Bernie; Dayal, Rohan; Parsa, Leila; Hirsa, Amir

2008-11-01

203

Anomalous absorption of electromagnetic radiation  

SciTech Connect

Transverse structure in a plasma at the critical layer can increase the coupling between electromagnetic and electrostatic waves and lead to enhanced absorption of the radiation. Simulations show cases of nearly 90% absorption of the incident energy. A ripple across the density gradient acts to focus the incoming electromagnetic radiation in the lower density regions coupling it to electrostatic modes through the transverse density gradients. A simple model of the absorption shows good agreement with the scalings observed in the computer simulations. Part of the reflected radiation is side scattered at {plus minus}{ital nk}{sub {ital t}}, where {ital k}{sub {ital t}} is the wave number of the transverse structure. This can reduce the directly backscattered radiation to 0.6% of the incident energy. Nonlinear coupling of the electrostatic waves leads to radiation at twice the incident frequency.

Rowland, H.L. (Space Plasma Branch, Plasma Physics Division, Naval Research Laboratory, Washington, D.C. 20375-5000 (United States))

1992-12-01

204

Electromagnetic Response of Weyl Semimetals  

NASA Astrophysics Data System (ADS)

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

Vazifeh, M. M.; Franz, M.

2013-07-01

205

Falling Magnets and Electromagnetic Braking  

NASA Astrophysics Data System (ADS)

The slow fall of a rare earth magnet through a copper pipe is a striking example of electromagnetic braking; this remarkable phenomenon has been the subject of a number of scientific paper s [1, 2]. In a pipe having radius R and wall thickness D, the terminal velocity of the falling magnet is proportional to (R?4)/D. It is interesting to ask what happens in the limit as D becomes very large. We report our experimental observations and theoretical predictions of the dependence of the terminal velocity on pipe radius R for large D. [1] Y. Levin, F.L. da Silveira, and F.B. Rizzato, ``Electromagnetic braking: A simple quantitative model''. American Journal of Physics, 74(9): p. 815-817 (2006). [2] J.A. Pelesko, M. Cesky, and S. Huertas, Lenz's law and dimensional analysis. American Journal of Physics, 3(1): p. 37-39. 2005.

Culbreath, Christopher; Palffy-Muhoray, Peter

2009-03-01

206

Pulsed power for electromagnetic launching  

SciTech Connect

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

Cowan, M

1980-12-01

207

Genetic Effects of Electromagnetic Waves  

NASA Astrophysics Data System (ADS)

The genetic effects of electromagnetic waves can be detected by different test-systems. The mutagenic effect of ionizing radiation can be developed on the levels of DNA and/or chromosomes. In numerous researches efficiency of micronucleus assay, alkaline single-cell gel electrophoresis, chromosomal aberrations test and FISH-technique and their different combinations for the detection of ionizing radiation-induced genotoxic effects are discussed. Also some molecular-biological approaches developed in the last years are presented.

Aroutiounian, Rouben; Hovhannisyan, Galina; Gasparian, Gennady

208

Pulsed power for electromagnetic launching  

Microsoft Academic Search

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

M. Cowan

1980-01-01

209

Genetic algorithms in engineering electromagnetics  

Microsoft Academic Search

This paper presents a tutorial and overview of genetic algorithms for electromagnetic optimization. Genetic-algorithm (GA) optimizers are robust, stochastic search methods modeled on the concepts of natural selection and evolution. The relationship between traditional optimization techniques and the GA is discussed. Step-by-step implementation aspects of the GA are detailed, through an example with the objective of providing useful guidelines for

J. Michael Johnson; V. Rahmat-Samii

1997-01-01

210

Electromagnetic calorimeter trigger at Belle  

NASA Astrophysics Data System (ADS)

The performance of CsI(T?) electromagnetic calorimeter trigger system in the Belle experiment is described. Two kinds of trigger schemes have been taken into account, namely a total energy trigger and a cluster counting trigger which are complementary to each other. In addition, the system has provided the online/offline luminosity information using the Bhabha event trigger scheme. An upgrade of the trigger is discussed.

Cheon, B. G.; Kim, Hee-Jong; Lee, S. H.; Won, E.; Park, I. C.; Hur, T. W.; Park, C. S.; Kim, S. K.; Kim, H. J.; Kim, H. O.; Chu, T. H.; Usov, Yu. V.; Aulchenko, V. M.; Kuzmin, A. S.; Bondar, A. E.; Shwartz, B.; Eidelman, S.; Krokovny, P.; Hayashii, H.; Sagawa, H.; Fukushima, M.

2002-11-01

211

Electromagnetic Spectrum of Am241  

Microsoft Academic Search

The electromagnetic spectrum of Am241 has been studied with a ten-inch bent-crystal spectrometer and a sodium iodide scintillation counter. Twelve gamma rays, sixteen Np L x-rays, and eight Am L x-rays have been measured. The gamma rays in Np have energies of 26.363, 33.199, 43.463, 59.568, 103, 113, 130, 159, 210, 270, 328, and 370 kev. The x-ray energies establish

Paul P. Day

1955-01-01

212

Electromagnetic Spectrum of Radium D  

Microsoft Academic Search

The electromagnetic spectrum of RaD has been studied by the proportional counter spectrometry technique. The work of the Curie Laboratory on the gamma-ray spectrum has been generally confirmed. However, the presumed K x-ray lines are of much lower intensity and occur at a lower energy than previously reported. The L x-ray intensity is 22 per hundred disintegrations, indicating 0.63 conversion

P. E. Damon; R. R. Edwards

1953-01-01

213

Electromagnetic Spectrum from QGP Fluid  

Microsoft Academic Search

We calculate thermal photon and electron pairdistribution from hot QCD matter produced in high energy heavy-ion collisions, based on a hydrodynamical model which is so tuned as to reproduce the recent experimental data at CERN SPS, and compare these electromagnetic spectra with experimental data given by CERN WA80 and CERES. We investigate mainly the effects of the off-shell properties of

Tetsufumi Hirano; Shin Muroya; Mikio Namiki

1997-01-01

214

Electromagnetically induced spatial light modulation  

E-print Network

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.

Zhao, L; Yelin, S F

2008-01-01

215

Teaching Electromagnetism Using Advanced Technologies  

NSDL National Science Digital Library

Michael Faraday was the first to realize that the shape of electromagnetic field lines is extraordinarily expressive of their dynamical effects. We can understand intuitively many things about the forces transmitted by the fields by looking at the topology of the field lines. This is especially true when the field lines are animated. This NSF-funded site has many examples of EM field lines.

Belcher, John

2003-10-10

216

Dark Energy, Gravitation and Electromagnetism  

E-print Network

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

B. G. Sidharth

2004-01-08

217

Electromagnetic scattering from biological tissue  

NASA Astrophysics Data System (ADS)

Based on the mathematical models of the experimentally fitted spectrum of index inhomogeneities, we analyze the electromagnetic field scattered from biological tissue. The resulting cross-spectral density matrices are expressed in spherical polar coordinates and the two-dimensional definition of polarization could be used. The results show that the polarization characteristics of the far scattered field depend closely on the types of the tissue.

Tong, Zhisong; Korotkova, Olga

2012-12-01

218

Electromagnetism on anisotropic fractal media  

NASA Astrophysics Data System (ADS)

Basic equations of electromagnetic fields in anisotropic fractal media are obtained using a dimensional regularization approach. First, a formulation based on product measures is shown to satisfy the four basic identities of the vector calculus. This allows a generalization of the Green-Gauss and Stokes theorems as well as the charge conservation equation on anisotropic fractals. Then, pursuing the conceptual approach, we derive the Faraday and Ampre laws for such fractal media, which, along with two auxiliary null-divergence conditions, effectively give the modified Maxwell equations. Proceeding on a separate track, we employ a variational principle for electromagnetic fields, appropriately adapted to fractal media, so as to independently derive the same forms of these two laws. It is next found that the parabolic (for a conducting medium) and the hyperbolic (for a dielectric medium) equations involve modified gradient operators, while the Poynting vector has the same form as in the non-fractal case. Finally, Maxwell's electromagnetic stress tensor is reformulated for fractal systems. In all the cases, the derived equations for fractal media depend explicitly on fractal dimensions in three different directions and reduce to conventional forms for continuous media with Euclidean geometries upon setting these each of dimensions equal to unity.

Ostoja-Starzewski, Martin

2013-04-01

219

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

SciTech Connect

In addition to producing loud gravitational waves, the dynamics of a binary black hole system could induce emission of electromagnetic radiation by affecting the behavior of plasmas and electromagnetic fields in their vicinity. We study how the electromagnetic fields are affected by a pair of orbiting black holes through the merger. In particular, we show how the binary's dynamics induce a variability in possible electromagnetically induced emissions as well as an enhancement of electromagnetic fields during the late-merge and merger epochs. These time dependent features will likely leave their imprint in processes generating detectable emissions and can be exploited in the detection of electromagnetic counterparts of gravitational waves.

Palenzuela, Carlos [Canadian Institute for Theoretical Astrophysics (CITA), Toronto, Ontario M5S 3H8 (Canada); Max-Planck-Institut fuer Gravitationsphysik, Albert-Einstein-Institut, Berlin, D-14476 Golm (Germany); Lehner, Luis [Perimeter Institute for Theoretical Physics, Waterloo, Ontario N2L 2Y5 (Canada); Department of Physics, University of Guelph, Guelph, Ontario N1G 2W1 (Canada); Canadian Institute For Advanced Research (CIFAR), Cosmology and Gravity Program (Canada); Yoshida, Shin [Department of Earth Science and Astronomy, Graduate School of Arts and Sciences, University of Tokyo, Meguro, Tokyo 153-8902 (Japan)

2010-04-15

220

Electromagnetic Effects in SDF Explosions  

SciTech Connect

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.

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

2010-02-12

221

An omnidirectional electromagnetic absorber made of metamaterials  

NASA Astrophysics Data System (ADS)

In a recent theoretical work by Narimanov and Kildishev (2009 Appl. Phys. Lett. 95 041106) an optical omnidirectional light absorber based on metamaterials was proposed, in which theoretical analysis and numerical simulations showed that all optical waves hitting the absorber are trapped and absorbed. Here we report the first experimental demonstration of an omnidirectional electromagnetic absorber in the microwave frequency. The proposed device is composed of non-resonant and resonant metamaterial structures, which can trap and absorb electromagnetic waves coming from all directions spirally inwards without any reflections due to the local control of electromagnetic fields. It is shown that the absorption rate can reach 99 per cent in the microwave frequency. The all-directional full absorption property makes the device behave like an 'electromagnetic black body', and the wave trapping and absorbing properties simulate, to some extent, an 'electromagnetic black hole.' We expect that such a device could be used as a thermal emitting source and to harvest electromagnetic waves.

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

2010-06-01

222

Electromagnetic wave in a relativistic magnetized plasma  

SciTech Connect

Results are presented from a theoretical investigation of the dispersion properties of a relativistic plasma in which an electromagnetic wave propagates along an external magnetic field. The dielectric tensor in integral form is simplified by separating its imaginary and real parts. A dispersion relation for an electromagnetic wave is obtained that makes it possible to analyze the dispersion and collisionless damping of electromagnetic perturbations over a broad parameter range for both nonrelativistic and ultrarelativistic plasmas.

Krasovitskiy, V. B. [Russian Academy of Sciences, Keldysh Institute of Applied Mathematics (Russian Federation)

2009-12-15

223

Nonlinear electromagnetic propulsion system and method  

Microsoft Academic Search

The nonlinear electromagnetic propulsion system (NEMPS) and method prescribes a electromagnetic propulsion system based on an extremely low frequency (ELF) radiating antenna structure driven by a matched high-current pulsed power supply. The ELF antenna structure resembles a modified three-dimensional multiple-turn loop antenna whose geometry is optimized for the production of reaction thrust rather than the radiation of electromagnetic energy into

Rex L. Schlicher; S. M. Rinaldi; D. J. Hall; P. M. Ranon; C. E. Davis; J. P. O'Loughlin; E. E. Lednum; A. W. Biggs; J. H. Degnan; D. J. Topp; D. W. Scholfield

1990-01-01

224

Thin sheet casting with electromagnetic pressurization  

DOEpatents

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.

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

1991-01-01

225

Scalar invariants in gravitational and electromagnetic fields  

E-print Network

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.

Zihua Weng

2008-11-01

226

Molecular Expressions: Science, Optics & You: Electromagnetic Radiation  

NSDL National Science Digital Library

This item is an interactive Java simulation on electromagnetic radiation, the family of wave-like phenomena which includes visible light. Users control amplitude and wavelength to explore how electromagnetic waves are propagated. Included is a detailed text tutorial. This item is part of a larger collection of reference materials and simulations on electricity and magnetism. See Related Materials on this page for links to additional materials by these authors on electromagnetic radiation.

Davidson, Michael; Abramowitz, Mortimer; Parry-Hill, Matthew J.

2008-08-21

227

Manager's Role in Electromagnetic Interference (EMI) Control  

NASA Technical Reports Server (NTRS)

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

Sargent, Noel B.; Lewis, Catherine C.

2013-01-01

228

Electromagnetic wave scattering by Schwarzschild black holes  

E-print Network

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

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

2009-05-20

229

Electromagnetic interactions at RHIC and LHC  

E-print Network

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

M. C. Guclu

2008-11-15

230

22.105 Electromagnetic Interactions, Fall 1998  

E-print Network

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 ...

Hutchinson, I. H. (Ian H.)

231

6.630 Electromagnetic Theory, Fall 2002  

E-print Network

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, ...

Kong, Jin Au, 1942-

232

Field equations of electromagnetic and gravitational fields  

E-print Network

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.

Zihua Weng

2007-09-16

233

Electromagnetic compatibility of nuclear power plants  

SciTech Connect

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.

Cabayan, H.S.

1983-01-01

234

Detection of electromagnetic waves using MEMS antennas  

SciTech Connect

We describe the design, fabrication and characterization of simple micromechanical structures that are capable of sensing static electric time varying electromagnetic fields. Time varying electric field sensing is usually achieved using an electromagnetic antenna and a receiver. However, these antenna-based approaches do not exhibit high sensitivity over a broad frequency (or wavelength) range. An important aspect of the present work is that, in contrast to traditional antennas, the dimensions of these micromechanical oscillators can be much smaller than the wavelength of the electromagnetic wave. We characterized the fabricated micromechanical oscillators by measuring their responses to time varying electric and electromagnetic fields.

Lavrik, Nickolay V [ORNL] [ORNL; Tobin, [Oak Ridge National Laboratory (ORNL)] [Oak Ridge National Laboratory (ORNL); Bowland, Landon T [ORNL] [ORNL

2011-01-01

235

Electromagnetic imaging and simulated annealing  

NASA Astrophysics Data System (ADS)

In contrast with acoustical imaging methods, for which the wave field is dominated by propagation effects, electromagnetic imaging of conductive media suffers from the diffusive behavior of the electromagnetic field. An important question to address when working toward the achievement of electromagnetic imaging concerns the possibility of resolving the diffusion damping. Exact inversion will be looking at the solvability of the integral equation relating a diffusive field to its dual wavefield. This equation is ill posed because its Laplace-like kernel makes the inverse problem of finding the dual wave field a notoriously difficult (both numerically and mathematically) one. Stochastic inversion is another alternative based on least squares fitting. In this inverse problem approach, extracting the wave field is still a relatively instable process, although the L2 misfit function for data without noise presents a global minimum. The simulated annealing overcomes this instability for parameterization of this problem designed as follows. The unknown wave field is expected to be a sequence of impulsive functions. The number of impulsive functions can be determined by using a statistical criterion, called AIC, which comes from the Prony technique. The simulated annealing is applied to the positions of the reflections, while the amplitudes, which are not taken as parameters, are obtained by linear fitting. The simulated annealing method proves to be efficient even in the presence of noise. Furthermore, this nonlinear numerical inversion furnishes statistical quantities which allows an estimation of the resolution. Simple synthetic examples illustrate the performance of the inversion, while a synthetic finite element example shows the final pseudo-seismic section to be processed by standard seismic migration techniques.

Gibert, Dominique; Virieux, Jean

1991-05-01

236

Electromagnetic fields in fractal continua  

NASA Astrophysics Data System (ADS)

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.

Balankin, Alexander S.; Mena, Baltasar; Patio, Julin; Morales, Daniel

2013-04-01

237

Logic for electromagnetic field patterns  

E-print Network

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

G. a. Kouzaev

2008-05-29

238

Electromagnetism with dimension-5 operators  

E-print Network

We derive, in curved spacetime, the most general Lorentz-violating electromagnetic Lagrangian containing dimension-five operators with one more derivative than the Maxwell term in the hypothesis that Lorentz symmetry is broken by a background four-vector $n_\\mu$. We then study, for the case of isotropic $n_\\mu$, the generation of cosmic magnetic fields at inflation and cosmic birefringence. In the limiting case of Minkowski spacetime, we find that other than the CPT-odd Myers-Pospelov term, there exists another CPT-odd term which gives rise to nontrivial dispersion and constitutive relations.

Campanelli, Leonardo

2014-01-01

239

Electromagnetic configurations of rail guns  

NASA Astrophysics Data System (ADS)

Some problems associated with the electromagnetic acceleration of macrobodies in a rail gun are examined. An approach to the design of rail gun configurations is proposed, and some basic rail gun schemes are synthesized. The alternative rail gun schemes are compared in terms of electrode potential and stability of the electrode gap with respect to parasitic current shunting. The effect of the ohmic resistance of the electrodes and of the additional magnetization field on the spatial structure of the discharge in the rail gun channel is discussed. A classification of rail gun modifications is presented.

Fat'yanov, O. V.; Ostashev, V. E.; Lopyrev, A. N.; Ul'Yanov, A. V.

1993-06-01

240

Particle acceleration by electromagnetic waves.  

PubMed

We consider the symmetry in the interaction of photons and electrons, which has led to a common description of electron and photon accelerations; effects such as photon Landau damping arise naturally from such a treatment. Intense electromagnetic waves can act as a photon mirror to charged particles. The subsequent acceleration is equivalent to the photon pulse accelerating electrons. During the interaction or reflection process, the charged particle can emit bursts of radiation similar to the radiation emitted from the particles during wave breaking of plasma waves. PMID:18218605

Bingham, R

2008-05-28

241

Electromagnetic weak turbulence theory revisited  

SciTech Connect

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

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

2012-10-15

242

IEEE TRANSACTIONS ON ELECTROMAGNETIC COMPATIBILITY, VOL. 40, NO. 1, FEBRUARY 1998 19 Ray Analysis of Electromagnetic  

E-print Network

IEEE TRANSACTIONS ON ELECTROMAGNETIC COMPATIBILITY, VOL. 40, NO. 1, FEBRUARY 1998 19 Ray Analysis of Electromagnetic Field Build-Up and Quality Factor of Electrically Large Shielded Enclosures Do-Hoon Kwon, Student--A high-frequency asymptotic ray solution is inves- tigated for predicting the electromagnetic field build

Burkholder, Robert J.

243

Compton Sources of Electromagnetic Radiation  

SciTech Connect

When a relativistic electron beam interacts with a high-field laser beam, intense and highly collimated electromagnetic radiation will be generated through Compton scattering. Through relativistic upshifting and the relativistic Doppler effect, highly energetic polarized photons are radiated along the electron beam motion when the electrons interact with the laser light. For example, X-ray radiation can be obtained when optical lasers are scattered from electrons of tens-of-MeV beam energy. Because of the desirable properties of the radiation produced, many groups around the world have been designing, building, and utilizing Compton sources for a wide variety of purposes. In this review article, we discuss the generation and properties of the scattered radiation, the types of Compton source devices that have been constructed to date, and the prospects of radiation sources of this general type. Due to the possibilities of producing hard electromagnetic radiation in a device that is small compared to the alternative storage ring sources, it is foreseen that large numbers of such sources may be constructed in the future.

Geoffrey Krafft,Gerd Priebe

2011-01-01

244

Electromagnetic Methods of Lightning Detection  

NASA Astrophysics Data System (ADS)

Both cloud-to-ground and cloud lightning discharges involve a number of processes that produce electromagnetic field signatures in different regions of the spectrum. Salient characteristics of measured wideband electric and magnetic fields generated by various lightning processes at distances ranging from tens to a few hundreds of kilometers (when at least the initial part of the signal is essentially radiation while being not influenced by ionospheric reflections) are reviewed. An overview of the various lightning locating techniques, including magnetic direction finding, time-of-arrival technique, and interferometry, is given. Lightning location on global scale, when radio-frequency electromagnetic signals are dominated by ionospheric reflections, is also considered. Lightning locating system performance characteristics, including flash and stroke detection efficiencies, percentage of misclassified events, location accuracy, and peak current estimation errors, are discussed. Both cloud and cloud-to-ground flashes are considered. Representative examples of modern lightning locating systems are reviewed. Besides general characterization of each system, the available information on its performance characteristics is given with emphasis on those based on formal ground-truth studies published in the peer-reviewed literature.

Rakov, V. A.

2013-11-01

245

Electromagnetic scattering from buried objects  

SciTech Connect

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.

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

1994-10-01

246

Millimeter Waves: Acoustic and Electromagnetic  

PubMed Central

This article is the presentation I gave at the D'Arsonval Award Ceremony on June 14, 2011 at the Bioelectromagnetics Society Annual Meeting in Halifax, Nova Scotia. It summarizes my research activities in acoustic and electromagnetic millimeter waves over the past 47 years. My earliest research involved acoustic millimeter waves, with a special interest in diagnostic ultrasound imaging and its safety. For the last 21 years my research expanded to include electromagnetic millimeter waves, with a special interest in the mechanisms underlying millimeter wave therapy. Millimeter wave therapy has been widely used in the former Soviet Union with great reported success for many diseases, but is virtually unknown to Western physicians. I and the very capable members of my laboratory were able to demonstrate that the local exposure of skin to low intensity millimeter waves caused the release of endogenous opioids, and the transport of these agents by blood flow to all parts of the body resulted in pain relief and other beneficial effects. PMID:22926874

Ziskin, Marvin C.

2012-01-01

247

Electromagnetic wave energy conversion research  

NASA Technical Reports Server (NTRS)

Known electromagnetic wave absorbing structures found in nature were first studied for clues of how one might later design large area man-made radiant-electric converters. This led to the study of the electro-optics of insect dielectric antennae. Insights were achieved into how these antennae probably operate in the infrared 7-14um range. EWEC theoretical models and relevant cases were concisely formulated and justified for metal and dielectric absorber materials. Finding the electromagnetic field solutions to these models is a problem not yet solved. A rough estimate of losses in metal, solid dielectric, and hollow dielectric waveguides indicates future radiant-electric EWEC research should aim toward dielectric materials for maximum conversion efficiency. It was also found that the absorber bandwidth is a theoretical limitation on radiant-electric conversion efficiency. Ideally, the absorbers' wavelength would be centered on the irradiating spectrum and have the same bandwith as the irradiating wave. The EWEC concept appears to have a valid scientific basis, but considerable more research is needed before it is thoroughly understood, especially for the complex randomly polarized, wide band, phase incoherent spectrum of the sun. Specific recommended research areas are identified.

Bailey, R. L.; Callahan, P. S.

1975-01-01

248

On gravitational-electromagnetic resonance  

E-print Network

This is an English translation of the paper M.B.Mensky, in: K.P.Stanyukovich (ed.), "Problems of Theory of Gravity and Elementary Particles", issue 6, Moscow, Atomizdat, 1975, p.181-190 (in Russian). This paper elaborates further the idea (formulated in 1971 by Braginsky and Mensky) of detecting high-frequency gravitational waves by observing resonance action of a gravitational wave on the electromagnetic wave in a closed resonator (waveguide). The phenomenon underlying such a detector was called gravitational-electromagnetic resonance (GER). In the present paper both closed (for example circular) resonator or waveguide and long (for example in the shape of a spiral) waveguide are considered as possible gravitational-wave detectors. High-frequency gravitational-wave detectors are now again actual (see A.M.Cruise and R.M.J.Ingley, Class. Quant. Grav. 22, S479, 2005), but the current literature on this topic does not cover all the issues discussed in the present paper.

Michael B. Mensky

2007-12-21

249

Measurement of Electromagnetic Parameters and FDTD Modeling of Ferrite Cores  

E-print Network

for electromagnetic compatibility (EMC) and signal integrity (SI) purposes. This includes characterizationMeasurement of Electromagnetic Parameters and FDTD Modeling of Ferrite Cores Jianfeng Xu #1 of constitutive electromagnetic properties of magneto- dielectric materials, i.e., their complex permittivity

Koledintseva, Marina Y.

250

Project no. 516369 Electromagnetic compatibility between rolling stock and  

E-print Network

Project no. 516369 Electromagnetic compatibility between rolling stock and rail are recalled in this section. Electromagnetic compatibility: The ability of an equipment or system to function compatibility EMI Electromagnetic interference ETSI European Telecommunications Standards Institute FM Frequency

Paris-Sud XI, Université de

251

Characterisation of electromagnetic compatibility drifts of nanoscale integrated  

E-print Network

Characterisation of electromagnetic compatibility drifts of nanoscale integrated circuit after interferences. For the first time an electromagnetic compatibility (EMC) qualification procedure is proposed to increasing usage of high speed and complex electronic systems, electromagnetic compatibility (EMC) is a major

Paris-Sud XI, Université de

252

Ben Zion Steinberg Electromagnetic Waves -Propagation and Scattering  

E-print Network

Ben Zion Steinberg Electromagnetic Waves - Propagation and Scattering Nano photonics Devices Antennas Miniaturization and Isolation Electromagnetic Waves - Propagation and Scattering-plasmonics Interlay of two-type rotation: Electromagnetic (e.g. Faraday rotation) Geometric (e.g. chirality

Steinberg, Ben

253

ANDERSON LOCALIZATION OF ELECTROMAGNETIC WAVES IN CONFINED DISORDERED DIELECTRIC MEDIA  

E-print Network

ANDERSON LOCALIZATION OF ELECTROMAGNETIC WAVES IN CONFINED DISORDERED DIELECTRIC MEDIA MARIAN RUSEK, Poland 1. Introduction Scattering of electromagnetic waves from varoius kind of obstacles is rich experimental demonstration that Anderson localization of electromagnetic waves is possible in three

Rusek, Marian

254

Electromagnets 1: Turn on the Power. Science in a Box.  

ERIC Educational Resources Information Center

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)

Whitman, Betsy Blizard

1992-01-01

255

Electromagnetic Visibility and Invisibility Massachusetts Institute of Technology  

E-print Network

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

Ciocan-Fontanine, Ionut

256

Improved Magnetic Fusion Energy Economics Via Massive Resistive Electromagnets  

E-print Network

Improved Magnetic Fusion Energy Economics Via Massive Resistive Electromagnets Robert D. Woolley using superconducting electromagnets, the recirculating power fraction needed to operate resistive electromagnets can be made as close to zero as needed for economy without requiring superconductors. Other

257

Electromagnetic signature of human cortical dynamics during wakefulness and sleep  

E-print Network

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

Destexhe, Alain

258

Pullback transformation in gyrokinetic electromagnetic simulations  

E-print Network

It is shown that a considerable improvement in the global gyrokinetic electromagnetic simulations can be achieved by a slight modification of the simulation scheme. The new scheme is verified, simulating a Toroidal Alfv\\'en Eigenmode in tokamak geometry at low perpendicular mode numbers, the so-called "MHD limit". Also, an electromagnetic drift mode has been successfully simulated in a stellarator.

Mishchenko, Alexey; Kleiber, Ralf; Cole, Michael

2014-01-01

259

NASA Applications for Computational Electromagnetic Analysis  

NASA Technical Reports Server (NTRS)

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

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

2011-01-01

260

Narrow field electromagnetic sensor system and method  

DOEpatents

A narrow field electromagnetic sensor system and method of sensing a characteristic of an object provide the capability to realize a characteristic of an object such as density, thickness, or presence, for any desired coordinate position on the object. One application is imaging. The sensor can also be used as an obstruction detector or an electronic trip wire with a narrow field without the disadvantages of impaired performance when exposed to dirt, snow, rain, or sunlight. The sensor employs a transmitter for transmitting a sequence of electromagnetic signals in response to a transmit timing signal, a receiver for sampling only the initial direct RF path of the electromagnetic signal while excluding all other electromagnetic signals in response to a receive timing signal, and a signal processor for processing the sampled direct RF path electromagnetic signal and providing an indication of the characteristic of an object. Usually, the electromagnetic signal is a short RF burst and the obstruction must provide a substantially complete eclipse of the direct RF path. By employing time-of-flight techniques, a timing circuit controls the receiver to sample only the initial direct RF path of the electromagnetic signal while not sampling indirect path electromagnetic signals. The sensor system also incorporates circuitry for ultra-wideband spread spectrum operation that reduces interference to and from other RF services while allowing co-location of multiple electronic sensors without the need for frequency assignments. 12 figs.

McEwan, T.E.

1996-11-19

261

Electromagnetic Induction Rediscovered Using Original Texts.  

ERIC Educational Resources Information Center

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)

Barth, Michael

2000-01-01

262

Forward electromagnetic scattering models for sea ice  

Microsoft Academic Search

Recent advances in forward modeling of the electromagnetic scattering properties of sea ice are presented. In particular, the principal results include the following: (1) approximate calculations of electromagnetic scattering from multilayer random media with rough interfaces, based on the distorted Born approximation and radiative transfer (RT) theory; (2) comprehensive theory of the effective complex permittivity of sea ice based on

K. M. Golden; M. Cheney; Kung-Hau Ding; A. K. Fung; Thomas C. Grenfell; D. Isaacson; Jin Au Kong; S. V. Nghiem; J. Sylvester; P. Winebrenner

1998-01-01

263

Electromagnetic bonding of plastics to aluminum  

NASA Technical Reports Server (NTRS)

Electromagnetic curing is used to bond strain gage to aluminum tensile bar. Electromagnetic energy heats only plastic/metal interface by means of skin effect, preventing degradation of heat-treated aluminum. Process can be easily applied to other metals joined by high-temperature-curing plastic adhesives.

Sheppard, A. T.; Silbert, L.

1980-01-01

264

Assessment and control of spacecraft electromagnetic interference  

NASA Technical Reports Server (NTRS)

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

1972-01-01

265

Can a wormhole generate electromagnetic field?  

E-print Network

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.

Mubasher Jamil

2008-05-07

266

Low-Frequency Electromagnetic Backscattering from Tunnels.  

National Technical Information Service (NTIS)

Low-frequency electromagnetic scattering from one or more tunnels in a lossy dielectric half-space is considered. The tunnel radii are assumed small compared to the wavelength of the electromagnetic field in the surrounding medium; a tunnel can thus be mo...

H. Y. Pao, K. Casey

2007-01-01

267

Walter Fendt Physics Applets: Electromagnetic Wave  

NSDL National Science Digital Library

This simulation shows a plane polarized electromagnetic wave propagating in positive x direction. The vectors of the electric field (red) are parallel to the y axis, the vectors of the magnetic field (blue) are parallel to the z axis. This applet illustrates the behavior of the fields in electromagnetic waves. This is part of a large collection of physics applets available in several languages.

Fendt, Walter

2007-01-29

268

Narrow field electromagnetic sensor system and method  

DOEpatents

A narrow field electromagnetic sensor system and method of sensing a characteristic of an object provide the capability to realize a characteristic of an object such as density, thickness, or presence, for any desired coordinate position on the object. One application is imaging. The sensor can also be used as an obstruction detector or an electronic trip wire with a narrow field without the disadvantages of impaired performance when exposed to dirt, snow, rain, or sunlight. The sensor employs a transmitter for transmitting a sequence of electromagnetic signals in response to a transmit timing signal, a receiver for sampling only the initial direct RF path of the electromagnetic signal while excluding all other electromagnetic signals in response to a receive timing signal, and a signal processor for processing the sampled direct RF path electromagnetic signal and providing an indication of the characteristic of an object. Usually, the electromagnetic signal is a short RF burst and the obstruction must provide a substantially complete eclipse of the direct RF path. By employing time-of-flight techniques, a timing circuit controls the receiver to sample only the initial direct RF path of the electromagnetic signal while not sampling indirect path electromagnetic signals. The sensor system also incorporates circuitry for ultra-wideband spread spectrum operation that reduces interference to and from other RF services while allowing co-location of multiple electronic sensors without the need for frequency assignments.

McEwan, Thomas E. (Livermore, CA)

1996-01-01

269

Quantization of Electromagnetic Fields in Cavities  

NASA Technical Reports Server (NTRS)

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.

Kakazu, Kiyotaka; Oshiro, Kazunori

1996-01-01

270

The Covariant Description of Electromagnetically Polarizable Media  

E-print Network

The form of the phenomenological stress-energy-momentum tensor for the electromagnetic field in a class of inhomogeneous, anisotropic magneto-electric media is calculated from first principles, leading to a coherent understanding of the phenomenological stresses and energy-momentum exchanges induced by electromagnetic interactions with such matter in terms of a fully relativistic covariant variational framework.

T. Dereli; J. Gratus; R. W. Tucker

2006-10-26

271

How Electrons consist of Electromagnetic Waves  

E-print Network

In this paper we investigate the connection between electrons and electromagnetic waves. We then propose how electrons could consist of electromagnetic waves. From this proposal we explain why electron-positron annihilation results in only gamma rays being formed, as well as how gamma rays can form electron-positron pairs. 1

Mark A. Newstead; Stephen C. Newstead

2011-01-01

272

The Teaching of Electromagnetism at University Level  

ERIC Educational Resources Information Center

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)

Houldin, J. E.

1974-01-01

273

Upper High School Students' Understanding of Electromagnetism  

ERIC Educational Resources Information Center

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

Saglam, Murat; Millar, Robin

2006-01-01

274

Wavelets and electromagnetic power system transients  

Microsoft Academic Search

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

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

1996-01-01

275

Electromagnetic Concepts in Mathematical Representation of Physics.  

ERIC Educational Resources Information Center

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

Albe, Virginie; Venturini, Patrice; Lascours, Jean

2001-01-01

276

Electromagnetic corrections to light hadron masses  

E-print Network

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

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

2010-11-18

277

Space-time Curvature of Classical Electromagnetism  

E-print Network

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

R. W. M. Woodside

2004-10-08

278

An electromagnetic black hole made of metamaterials  

E-print Network

Traditionally, a black hole is a region of space with huge gravitational field in the means of general relativity, which absorbs everything hitting it including the light. In general relativity, the presence of matter-energy densities results in the motion of matter propagating in a curved spacetime1, which is similar to the electromagnetic-wave propagation in a curved space and in an inhomogeneous metamaterial2. Hence one can simulate the black hole using electromagnetic fields and metamaterials. In a recent theoretical work, an optical black hole has been proposed based on metamaterials, in which the numerical simulations showed a highly efficient light absorption3. Here we report the first experimental demonstration of electromagnetic black hole in the microwave frequencies. The proposed black hole is composed of non-resonant and resonant metamaterial structures, which can absorb electromagnetic waves efficiently coming from all directions due to the local control of electromagnetic fields. Hence the elect...

Cheng, Qiang

2009-01-01

279

Noninvasive valve monitor using alternating electromagnetic field  

DOEpatents

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.

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

1993-03-16

280

Noninvasive valve monitor using alternating electromagnetic field  

DOEpatents

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.

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

1993-01-01

281

Electromagnetic field with constraints and Papapetrou equation  

E-print Network

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

Z. Ya. Turakulov; A. T. Muminov

2006-01-12

282

Simplified equivalent modelling of electromagnetic emissions from printed circuit boards.  

E-print Network

??Characterization of electromagnetic emissions from printed circuit boards (PCBs) is an important issue in electromagnetic compatibility (EMC) design and analysis of modern electronic systems. This (more)

Tong, Xin

2010-01-01

283

Controlling Electromagnetic Fields with Tensor Transmission-Line Metamaterials.  

E-print Network

??The advent of metamaterials and transformation electromagnetics have revolutionized the use of materials in the control of electromagnetic fields. Metamaterials enabled the control of material (more)

Gok, Gurkan

2014-01-01

284

The electromagnetic momentum of static charge-current distributions  

NASA Astrophysics Data System (ADS)

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.

Franklin, Jerrold

2014-09-01

285

Electromagnetic braking for Mars spacecraft  

NASA Technical Reports Server (NTRS)

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

Holt, A. C.

1986-01-01

286

Electromagnetic Induction with Neodymium Magnets  

NASA Astrophysics Data System (ADS)

In April 1820, Hans Christian rsted noticed that the needle of a nearby compass deflected briefly from magnetic north each time the electric current of the battery he was using for an unrelated experiment was turned on or off. Upon further investigation, he showed that an electric current flowing through a wire produces a magnetic field. In 1831 Michael Faraday and Joseph Henry separately expanded on rsted's discovery by showing that a changing magnetic field produces an electric current. Heinrich Lenz found in 1833 that an induced current has the opposite direction from the electromagnetic force that produced it. This paper describes an experiment that can help students to develop an understanding of Faraday's law and Lenz's law by studying the emf generated as a magnet drops through a set of coils having increasing numbers of turns.

Wood, Deborah; Sebranek, John

2013-09-01

287

Electromagnetic scattering by impedance structures  

NASA Technical Reports Server (NTRS)

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.

Balanis, Constantine A.; Griesser, Timothy

1987-01-01

288

Electromagnetic Signatures of SMBH Coalescence  

NASA Technical Reports Server (NTRS)

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

Schnittman, Jeremy

2012-01-01

289

Electromagnetic-gravitational energy systems  

NASA Technical Reports Server (NTRS)

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.

Schatten, K. H.

1981-01-01

290

Electromagnetic launchers for space applications  

NASA Technical Reports Server (NTRS)

An electromagnetic launcher (EML) was designed for NASA-Langley to boost large models to hypervelocity for flight evaluation. Two different concepts were developed using railgun and coilgun principles. A coilgun was designed to accelerate a 14-kg mass to 6 km/s and, by adding additional equipment, to accelerate a 10-kg mass to 11 km/s. The railgun system was designed to accelerate only 14 kg to 6 km/s. Of significance in this development is the opportunity to use the launcher for aeroballistic research of the upper atmosphere, eventually placing packages in low earth orbit using a small rocket. The authors describe the railgun and coilgun launch designs and suggest a reconfiguration for placement of 150-kg parcels into low earth orbit for aeroballistic studies and possible space lab support. Each design is detailed along with the performance adjustments which would be required for circular orbit payload placement.

Schroeder, J. M.; Gully, J. H.; Driga, M. D.

1989-01-01

291

ELVIS - ELectromagnetic Vector Information Sensor  

E-print Network

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.

Bergman, J E S; Thid, B; Ananthakrishnan, S; Wahlund, J E; Karlsson, R L; Puccio, W; Carozzi, T D; Kale, P

2005-01-01

292

Electromagnetic Calorimeter for Hades Experiment  

NASA Astrophysics Data System (ADS)

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

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

2014-06-01

293

Tracking Electromagnetic Energy With SQUIDs  

NASA Technical Reports Server (NTRS)

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

2005-01-01

294

Ultrarelativistic electromagnetic pulses in plasmas  

NASA Technical Reports Server (NTRS)

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.

Ashour-Abdalla, M.; Leboeuf, J. N.; Tajima, T.; Dawson, J. M.; Kennel, C. F.

1981-01-01

295

Formal analysis of electromagnetic optics  

NASA Astrophysics Data System (ADS)

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.

Khan-Afshar, Sanaz; Hasan, Osman; Tahar, Sofine

2014-09-01

296

ELVIS - ELectromagnetic Vector Information Sensor  

E-print Network

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.

J. E. S. Bergman; L. hln; O. Stl; B. Thid; S. Ananthakrishnan; J. -E. Wahlund; R. L. Karlsson; W. Puccio; T. D. Carozzi; P. Kale

2005-09-29

297

Advanced studies of electromagnetic scattering  

NASA Technical Reports Server (NTRS)

In radar signature applications it is often desirable to generate the range profiles and inverse synthetic aperture radar (ISAR) images of a target. They can be used either as identification tools to distinguish and classify the target from a collection of possible targets, or as diagnostic/design tools to pinpoint the key scattering centers on the target. The simulation of synthetic range profiles and ISAR images is usually a time intensive task and computation time is of prime importance. Our research has been focused on the development of fast simulation algorithms for range profiles and ISAR images using the shooting and bouncing ray (SBR) method, a high frequency electromagnetic simulation technique for predicting the radar returns from realistic aerospace vehicles and the scattering by complex media.

Ling, Hao

1994-01-01

298

Broadband cavity electromagnetically induced transparency  

SciTech Connect

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.

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

2011-10-15

299

Integrated Circuit Electromagnetic Immunity Handbook  

NASA Astrophysics Data System (ADS)

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.

Sketoe, J. G.

2000-08-01

300

An electromagnetic black hole made of metamaterials  

E-print Network

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

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

2009-10-12

301

Modeling Electromagnetic Scattering From Complex Inhomogeneous Objects  

NASA Technical Reports Server (NTRS)

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.

Deshpande, Manohar; Reddy, C. J.

2011-01-01

302

Interaction of electromagnetic fields and biological tissues  

NASA Astrophysics Data System (ADS)

This paper deals with the electromagnetic field interact in biological tissues. It is actually one of the important challenges for the electromagnetic field for the recent years. The experimental techniques are use in Broad-band Dielectric Measurement (BDM) with LCR meters. The authors used Bones and scales of Fish taken from Narmada River (Rajghat Dist. Barwani) as biological tissues. Experimental work carried out done in inter-university consortium (IUC) Indore. The major difficulties that appear are related to the material properties, to the effect of the electromagnetic problem and to the thermal model of the biological tissues.

Darshan Shrivastava, Bhakt; Barde, Ravindra; Mishra, Ashutosh; Phadke, S.

2014-09-01

303

Mass continuity equation in the electromagnetic field  

E-print Network

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

Ying Weng; Zi-Hua Weng

2009-09-07

304

An AWE Implementation for Electromagnetic Analysis  

NASA Technical Reports Server (NTRS)

Although full wave electromagnetic systems are large and cumbersome to solve, typically only a few parameters, such as input impedance, S parameters, and far field pattern, are needed by the designer or analyst. A reduced order modeling of these parameters is therefore an important consideration in minimizing the the CPU requirements. The Asymptotic Waveform Evaluation (AWE) method is one approach to construct a reduced order model of the input impedance or other useful electromagnetic parameters. We demonstrate its application and validity when used in conjunction with the finite element method to simulate full wave electromagnetic problems.

Gong, Jian; Volakis, John L.

1996-01-01

305

Varying Electromagnetic Coupling and Primordial Magnetic Fields  

E-print Network

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

O. Bertolami; R. Monteiro

2005-04-08

306

Invariants in electromagnetic and gravitational adjoint fields  

E-print Network

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.

Zihua Weng

2008-05-21

307

Geant4 Electromagnetic Physics for LHC Upgrade  

NASA Astrophysics Data System (ADS)

In this work we present recent progress in Geant4 electromagnetic physics modelling, with an emphasis on the new refinements for the processes of multiple and single scattering, ionisation, high energy muon interactions, and gamma induced processes. The future LHC upgrade to 13 TeV will bring new requirements regarding the quality of electromagnetic physics simulation: energy, particle multiplicity, and statistics will be increased. The evolution of CPU performance and developments for Geant4 multi-threading connected with Geant4 electromagnetic physics sub-packages will also be discussed.

Ivanchenko, V. N.; Apostolakis, J.; Bagulya, A.; Bogdanov, A.; Grichine, V.; Incerti, S.; Ivantchenko, A.; Maire, M.; Pandola, L.; Pokorski, W.; Sawkey, D.; Schaelicke, A.; Schenk, M.; Schwarz, S.; Urban, L.; Geant4 electromagnetic physics working Groups

2014-06-01

308

Scattering by an electromagnetic radiation field  

E-print Network

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

Bini, Donato

2014-01-01

309

Development of the strong electromagnet wiggler  

SciTech Connect

The Strong Electromagnet (SEM) wiggler is a permanent magnet-assisted electromagnet under development at the Lawrence Livermore National Laboratory (LLNL) as part of the Induction Linac Free-Electron-Laser (IFEL) program. This concept uses permanent magnets within the wiggler to provide a reverse bias flux in the iron and thus delay the onset of magnetic saturation. The electromagnet coils determine th4e wiggler field and operate at low current densities by virtue of their placement away from the midplane. The authors describe the design approach used and test data from a 7-period wiggler prototype that includes curved pole tips to provide wiggler-plane focusing.

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

1988-03-01

310

Development of a strong electromagnet wiggler  

SciTech Connect

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.

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

1987-01-01

311

Electromagnetic characterization of metallic sensory alloy  

NASA Astrophysics Data System (ADS)

Ferromagnetic shape-memory alloy (FSMA) particles undergo changes in both electromagnetic properties and crystallographic structure when strained. When embedded in a structural material, these attributes can provide sensory output of the strain state of the structure. In this work, a detailed characterization of the electromagnetic properties of a FSMA under development for sensory applications is performed. In addition, a new eddy current probe is used to interrogate the electromagnetic properties of individual FSMA particles embedded in the sensory alloy during controlled fatigue tests on the multifunctional material.

Wincheski, Buzz; Simpson, John; Wallace, Terryl; Newman, Andy; Leser, Paul; Lahue, Rob

2013-01-01

312

Counting energy packets in the electromagnetic wave  

E-print Network

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

Stefan Popescu; Bernhard Rothenstein

2007-05-18

313

Electromagnetic Characterization Of Metallic Sensory Alloy  

NASA Technical Reports Server (NTRS)

Ferromagnetic shape-memory alloy (FSMA) particles undergo changes in both electromagnetic properties and crystallographic structure when strained. When embedded in a structural material, these attributes can provide sensory output of the strain state of the structure. In this work, a detailed characterization of the electromagnetic properties of a FSMA under development for sensory applications is performed. In addition, a new eddy current probe is used to interrogate the electromagnetic properties of individual FSMA particles embedded in the sensory alloy during controlled fatigue tests on the multifunctional material.

Wincheski, Russell A.; Simpson, John; Wallace, Terryl A.; Newman, John A.; Leser, Paul; Lahue, Rob

2012-01-01

314

Spinors and pre-metric electromagnetism  

E-print Network

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.

David Delphenich

2005-12-22

315

Mechanics background influences students' conceptions in electromagnetism  

NSDL National Science Digital Library

The understanding of different aspects of the 'field' concept in electromagnetism was tested with high school students and prospective teachers of technological disciplines. Some of the observed difficulties could be interpreted as originating from the change in methodological approaches employed in different domains of physics: electromagnetism vis-a-vis mechanics. This may have encouraged students to misinterpret the nature of force interactions and work-energy conversions in the presence of electromagnetic fields. Clarification of the rationale for introducing the 'field' concept, especially in its historical aspect, could be useful in coping with the teaching-learning problems evidenced in this study and other research.

Galili, Igal

2006-05-08

316

On the Axioms of Topological Electromagnetism  

E-print Network

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

D. H. Delphenich

2003-11-26

317

Scattering by an electromagnetic radiation field  

E-print Network

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

Donato Bini; Andrea Geralico

2014-08-21

318

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

319

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

E-print Network

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

Cdric Lorc

2009-01-27

320

Electromagnetic field radiation model for lightning strokes to tall structures  

Microsoft Academic Search

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

H. Motoyama; W. Janischewskyj; A. M. Hussein; W. A. Chisholm; J. S. Chang; R. Rusan

1996-01-01

321

Reverberating chambers as sources of stochastic electromagnetic fields  

Microsoft Academic Search

Reverberating chambers are of recognized relevance in many EMC applications since they allow us to generate a reference electromagnetic statistical field. This paper investigates the electromagnetic field in reverberating chambers. Reverberating chambers are large overmoded cavities wherein a nonstationary electromagnetic field is present. This electromagnetic field is stochastic in nature; therefore, proper analytical tools need to be considered in order

Paolo Corona; Giuseppe Ferrara; Maurizio Migliaccio

1996-01-01

322

An Efficient Algorithm for Shielding Electromagnetic Topological Diagram  

Microsoft Academic Search

An electromagnetic topology method used to analyze interactions between electronic systems and electromagnetic environment is presented. Combining electromagnetic topology model with the graph theory, an efficient algorithm is obtained. The algorithm can find out all the paths which have a lower shielding coefficient than the given threshold K in the shielding electromagnetic topological diagram.

Yongfeng Wang; Chengda Yu; Chaowei Zhang

2010-01-01

323

Underground Electromagnetic Pulse: Four Representative Models.  

National Technical Information Service (NTIS)

I describe four phenomenological models by which an underground nuclear explosion may generate electromagnetic pulses: Compton current asymmetry (or ''Compton dipole''); Uphole conductor currents (or ''casing currents''); Diamagnetic cavity plasma (or ''m...

L. F. Wouters

1989-01-01

324

Advances in non-planar electromagnetic prototyping  

E-print Network

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

Ehrenberg, Isaac M

2013-01-01

325

Electromagnetic thrusters for spacecraft prime propulsion  

NASA Technical Reports Server (NTRS)

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.

Rudolph, L. K.; King, D. Q.

1984-01-01

326

Dynamic programming applied to electromagnetic satellite actuation  

E-print Network

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 ...

Eslinger, Gregory John

2013-01-01

327

Electromagnetic Pulse and the Electric Power Network.  

National Technical Information Service (NTIS)

This paper defines the nuclear electromagnetic pulse (EMP) - electric power system interaction problem. A description of high altitude EMP (HEMP) characteristics, source region EMP (SREMP) characteristics, and magnetohydrodynamics EMP (MHD-EMP) characteri...

K. W. Klein, P. R. Barnes, H. W. Zaininger

1984-01-01

328

Galium Electromagnetic (GEM) Thruster Concept and Design  

NASA Technical Reports Server (NTRS)

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.

Polzin, Kurt A.; Markusic, Thomas E.

2005-01-01

329

Televisions, Video Privacy, and Powerline Electromagnetic Interference  

E-print Network

televisions (TVs) spanning multiple makes, models, and underlying technolo- gies. In addition to being without fee provided that copies are not made or distributed for profit or commercial advantageTelevisions, Video Privacy, and Powerline Electromagnetic Interference Miro Enev University

Matsuoka, Yoky

330

Electromagnetic Fields and Public Health: Mobile Phones  

MedlinePLUS

... warrant further research of mobile phone use and brain cancer risk. In particular, with the recent popularity of ... link Interphone study on mobile phone use and brain cancer risk [pdf 176kb] The International Electromagnetic Fields Project ...

331

Tour of the Electromagnetic Spectrum Book  

NSDL National Science Digital Library

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

332

Tour of the Electromagnetic Spectrum Booklet  

NSDL National Science Digital Library

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

Benesch, Troy

2010-01-01

333

Electromagnetic radiation from beam-plasma instabilities  

NASA Technical Reports Server (NTRS)

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.

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

1982-01-01

334

Method and apparatus for measuring electromagnetic radiation  

NASA Technical Reports Server (NTRS)

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.

Been, J. F. (inventor)

1973-01-01

335

Progress In Electromagnetics Research Symposium (PIERS)  

NASA Technical Reports Server (NTRS)

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

1993-01-01

336

Electromagnetic ion/ion cyclotron instability  

SciTech Connect

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

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

1991-01-01

337

Calculation of electromagnetic force in electromagnetic forming process of metal sheet  

SciTech Connect

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.

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

2010-06-15

338

Measurements in an electromagnetic test laboratory  

NASA Astrophysics Data System (ADS)

Electromagnetic compatibility test equipment and the specially built strong electromagnetic pulses immunity test system, developed in order to control the characteristics of aerospace communication systems, are described. The compatability tests are carried out at frequencies from 10KHz to 10GHz in a Faraday cage. Measurement is implemented with an optical transmission bus. The extremely high voltage pulse generator assembled for immunity testing is based on Marx generators. Measurement and command are made via optical circuits.

Raveu, Bernard

1987-01-01

339

Electromagnetically Induced Transparency for X Rays  

Microsoft Academic Search

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-13s and 1s-13p (800nm). The minimum laser intensity required to observe electromagnetically induced transparency

Christian Buth; Robin Santra; Linda Young

2007-01-01

340

Electromagnetically Induced Transparency for X Rays  

Microsoft Academic Search

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⁻¹3s and 1s⁻¹3p (800 nm). The minimum laser intensity required to observe electromagnetically induced

Christian Buth; Robin Santra; Linda Young

2007-01-01

341

Singular Modes of the Electromagnetic Field  

E-print Network

We show that the mode corresponding to the point of essential spectrum of the electromagnetic scattering operator is a vector-valued distribution representing the square root of the three-dimensional Dirac's delta function. An explicit expression for this singular mode in terms of the Weyl sequence is provided and analyzed. An essential resonance thus leads to a perfect localization (confinement) of the electromagnetic field, which in practice, however, may result in complete absorption.

Neil V. Budko; Alexander B. Samokhin

2006-06-15

342

Electromagnetic Fields in the QCD Vacuum  

E-print Network

Quarks play an active role in shaping the QCD vacuum structure. Being dual carriers of both `color' and `electric' charges they also respond to externally applied electromagnetic fields. Thus, in principle, the vacuum of strong interactions influences higher order QED processes such as photon-photon scattering. We survey here the current status of the understanding of the vacuum structure of strong interactions, and take a fresh look at its electromagnetic properties.

Johann Rafelski; H. -Thomas Elze

1998-06-16

343

Some theorems in gravitational and electromagnetic fields  

E-print Network

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.

Zihua Weng

2008-03-30

344

Generating highly uniform electromagnetic field characteristics  

DOEpatents

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

Crow, James Terry (Albuquerque, NM)

1998-01-01

345

Generating highly uniform electromagnetic field characteristics  

DOEpatents

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.

Crow, J.T.

1998-02-10

346

Generating highly uniform electromagnetic field characteristics  

DOEpatents

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.

Crow, J.T.

1998-05-05

347

Generating highly uniform electromagnetic field characteristics  

DOEpatents

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

Crow, James T. (Albuquerque, NM)

1997-01-01

348

Generating highly uniform electromagnetic field characteristics  

DOEpatents

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.

Crow, J.T.

1997-06-24

349

Generating highly uniform electromagnetic field characteristics  

DOEpatents

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

Crow, James T. (Albuquerque, NM)

1998-01-01

350

Electromagnetic Corrections in Staggered Chiral Perturbation Theory  

E-print Network

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

C. Bernard; E. D. Freeland

2010-11-17

351

Electromagnetic Transport from Microtearing Mode Turbulence  

SciTech Connect

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.

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

352

Electromagnetic Transport From Microtearing Mode Turbulence  

SciTech Connect

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.

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

353

Electromagnetic and spin polarisabilities in lattice QCD  

E-print Network

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

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

2006-10-02

354

Aircraft Lightning Electromagnetic Environment Measurement  

NASA Technical Reports Server (NTRS)

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.

Ely, Jay J.; Nguyen, Truong X.; Szatkowski, George N.

2011-01-01

355

Donuts make diffractionless electromagnetic waves  

NASA Astrophysics Data System (ADS)

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.

Tsai, Ya-Lun; Lu, Jyun-Hong; Chiu, Hua-Kung; Chen, Ching-Yi; Chen, Chii-Chang; Chang, Jenq-Yang

2012-01-01

356

Inertia, Electromagnetism and Fluid Dynamics  

NASA Astrophysics Data System (ADS)

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.

Martins, Alexandre A.; Pinheiro, Mario J.

2008-01-01

357

Electromagnetic launch of lunar material  

NASA Technical Reports Server (NTRS)

Lunar soil can become a source of relatively inexpensive oxygen propellant for vehicles going from low Earth orbit (LEO) to geosynchronous Earth orbit (GEO) and beyond. This lunar oxygen could replace the oxygen propellant that, in current plans for these missions, is launched from the Earth's surface and amounts to approximately 75 percent of the total mass. The reason for considering the use of oxygen produced on the Moon is that the cost for the energy needed to transport things from the lunar surface to LEO is approximately 5 percent the cost from the surface of the Earth to LEO. Electromagnetic launchers, in particular the superconducting quenchgun, provide a method of getting this lunar oxygen off the lunar surface at minimal cost. This cost savings comes from the fact that the superconducting quenchgun gets its launch energy from locally supplied, solar- or nuclear-generated electrical power. We present a preliminary design to show the main features and components of a lunar-based superconducting quenchgun for use in launching 1-ton containers of liquid oxygen, one every 2 hours. At this rate, nearly 4400 tons of liquid oxygen would be launched into low lunar orbit in a year.

Snow, William R.; Kolm, Henry H.

1992-01-01

358

Progress in Electromagnetic Research Letters, 19, (2010), 147-154. Electromagnetic wave scattering by a thin layer in  

E-print Network

Progress in Electromagnetic Research Letters, 19, (2010), 147-154. 1 #12;Electromagnetic wave of electromagnetic (EM) waves by many small particles (bodies), embedded in a thin layer, is studied. Physical: electromagnetic waves; wave scattering by many small bodies; smart materials. 1 Introduction It is known (see, e

359

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

E-print Network

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

Haykin, Simon

360

Electromagnetic Scattering by Particles and Particle Groups  

NASA Astrophysics Data System (ADS)

Preface; Acknowledgements; 1. Introduction; 2. The macroscopic Maxwell equations and monochromatic fields; 3. Fundamental homogeneous-medium solutions of the macroscopic Maxwell equations; 4. Basic theory of frequency-domain electromagnetic scattering by a fixed finite object; 5. Far-field scattering; 6. The Foldy equations; 7. The Stokes parameters; 8. Poynting-Stokes tensor; 9. Polychromatic electromagnetic fields; 10. Polychromatic scattering by fixed and randomly changing objects; 11. Measurement of electromagnetic energy flow; 12. Measurement of the Stokes parameters; 13. Description of far-field scattering in terms of actual optical observables; 14. Electromagnetic scattering by a small random group of sparsely distributed particles; 15. Statistically isotropic and mirror-symmetric random particles; 16. Numerical computations and laboratory measurements of electromagnetic scattering; 17. Far-field observables: qualitative and quantitative traits; 18. Electromagnetic scattering by discrete random media: far field; 19. Near-field scattering by a sparse discrete random medium: microphysical radiative transfer theory; 20. Radiative transfer in plane-parallel particulate media; 21. Weak localization; 22. Epilogue; Appendix A. Dyads and dyadics; Appendix B. Free-space dyadic Green's function; Appendix C. Euler rotation angles; Appendix D. Spherical-wave expansion of a plane wave in the far zone; Appendix E. Integration quadrature formulas; Appendix F. Wigner d-functions; Appendix G. Stationary phase evolution of a double integral; Appendix H. Hints and answers to selected problems; Appendix I. List of acronyms; References; Index.

Mishchenko, Michael I.

2014-04-01

361

Constraints on Nubular Electromagnetic Pulses  

NASA Astrophysics Data System (ADS)

Chondritic meteorites contain an abundance of silicate minerals with opaque inclusions of oxides, sulfides, and metals. These host silicates interact differently from their enclosed opaques to electromagnetic (EM) radiation; specifically, silicates are inefficient at absorbing EM energy in the visible and near infrared while metals, sulfides, and Fe oxides absorb strongly in this frequency range. In the presence of a strong electromagnetic pulse (EMP), this preferential absorption leads to the selective heating of the opaque inclusions and can produce unique textures ("dirty snowballs": intimate, ~spherical intergrowths of silicate and opaque minerals with radii of < 1 to 10 micrometers) that record the passage of the EMP. Many chondrules, CAIs, and isolated silicate grains within chondritic meteorites exhibit these unique features, suggesting that strong EMPs were common in the early solar nebula [1]. Here we discuss new constraints on nebular EMPs obtained from both experimental simulations and calculations of radiative heat transport. To test the feasibility of producing "dirty snowball" textures by EMP heating, olivines and pyroxenes containing metal and sulfide inclusions were heated with a 10 watt, argon-ion, CW laser operated at 514 nm. Comparisons between meteoritic "dirty snowball" textures and experimentally produced textures confirm the ability to produce the meteoritic textures by EMP heating and suggest heating times and fluxes of 0.25 to 10 seconds and 10^9 to 10^10 ergs cm^-2 sec^-1. Fluxes less than 10^9 ergs cm^-2 sec^-1 were insufficient to melt metal and sulfide inclusions, while fluxes greater than 10^10 ergs cm^-2 sec^-1 resulted in complete melting of metal, sulfide, and silicates. The experimentally determined heating time scales suggest that radiative equilibrium was reached in the "dirty snowball" formation process, indicating that the range of observed textures is controlled by cooling rates. Calculations of radiative absorption and emission allow further constraints to be placed on the EMPs responsible for "dirty snowball" formation. The absorption and emission efficiencies of grains in a blackbody radiation field were determined by calculating Planck mean cross sections for olivine, pyroxene, and iron as a function of grain size [2,3]. This information was combined with conductive heat flow calculations to determine the behavior of olivine and pyroxene grains with small inclusions of metal. Results indicate that "dirty snowball" formation results only over a narrow flux range for a given multiphase assemblage, with higher fluxes required for smaller, more transparent, or more refractory grains. For a 100-mm olivine chondrule containing a 10-micrometer "dirty snowball," the required flux is ~9 +- 1 x 10^8 ergs cm^-2 sec^-1, with a minimum pulse duration of 4 seconds (assuming an initial grain temperature of 500 K prior to heating). These values are in good agreement with experimentally determined values. The results show that pulses energetic enough to create "dirty snowballs" are also capable of producing the total melting required for chondrule formation with only slight increases in flux, or with only marginally different grain properties (e.g., more opaque inclusions, lower melting points, higher absorption cross sections). Because of the temperature and grain size dependence of the Planck mean cross sections of silicates, an EMP of the type described above will selectively melt larger aggregates and individual grains (>100 micrometer) while leaving smaller aggregates and grains unmelted. Therefore, natural products of EMP heating are: 1) the formation of chondrules in a sustained dusty environment, 2) a paucity of small chondrules, and 3) residual grains relatively unaffected by the EMPs. References: [1] Eisenhour D. D. and Buseck P. R. (1993) LPSC XXIV, 435-436. [2] Falk S. W. and Scalo J. M. (1975) Ap. J., 202, 690-695. [3] Gilman R. C. (1974) Ap. J. Supp., 268, 28, 397-403.

Eisenhour, D. D.; Buseck, P. R.

1993-07-01

362

Is Electromagnetic Gravity Control Possible?  

SciTech Connect

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.

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

363

Reflection and refraction of transient electromagnetic wave on a flat surface.  

E-print Network

??The problem is effect of electromagnetic wave. When electromagnetic wave obliquely transmitted through two different medias ,electromagnetic wave undergoes reflection and refraction at the interface (more)

Chou, Sue-kai

2012-01-01

364

Gauge Symmetry and Gravito-Electromagnetism  

E-print Network

A tensor description of perturbative Einsteinian gravity about an arbitrary background spacetime is developed. By analogy with the covariant laws of electromagnetism in spacetime, gravito-electromagnetic potentials and fields are defined to emulate electromagnetic gauge transformations under substitutions belonging to the gauge symmetry group of perturbative gravitation. These definitions have the advantage that on a flat background, with the aid of a covariantly constant timelike vector field, a subset of the linearised gravitational field equations can be written in a form that is fully analogous to Maxwell's equations (without awkward factors of 4 and extraneous tensor fields). It is shown how the remaining equations in the perturbed gravitational system restrict the time dependence of solutions to these equations and thereby prohibit the existence of propagating vector fields. The induced gravito-electromagnetic Lorentz force on a test particle is evaluated in terms of these fields together with the torque on a small gyroscope. It is concluded that the analogy of perturbative gravity to Maxwell's description of electromagnetism can be valuable for (quasi-)stationary gravitational phenomena but that the analogy has its limitations.

Simon J. Clark; Robin W. Tucker

2000-03-31

365

Scattering of Electromagnetic Waves, Numerical Simulations  

NASA Astrophysics Data System (ADS)

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 applications of this rapidly expanding, interdisciplinary field. It covers both introductory and advanced material and provides students and researchers in remote sensing as well as imaging, optics, and electromagnetic theory with a one-stop reference to a wealth of current research results. Plus, Scattering of Electromagnetic Waves contains detailed discussions of both analytical and numerical methods, including cutting-edge techniques for the recovery of earth/land parametric information. The three volumes are entitled respectively Theories and Applications, Numerical Simulation, and Advanced Topics. In the second volume, Numerical Simulations, Leung Tsang (University of Washington) Jin Au Kong (MIT), Kung-Hau Ding (Air Force Research Lab), and Chi On Ao (MIT) cover: Layered media simulations Rough surface and volume scattering simulations Dense media models and simulations Electromagnetic scattering by discrete scatterers and a buried object Scattering by vertical cylinders above a surface Electromagnetic waves scattering by vegetation Computational methods and programs used for performing various simulations

Tsang, Leung; Kong, Jin Au; Ding, Kung-Hau; Ao, Chi On

2001-05-01

366

Upper High School Students' Understanding of Electromagnetism  

NASA Astrophysics Data System (ADS)

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 students in Turkey (n = 120) and England (n = 152). A separate test consisting of 10 questions on the visualization of spatial rotation was used to investigate the hypothesis that students ability to visualize three-dimensional situations from two-dimensional representations might influence learning of electromagnetism. Many students responses showed misunderstandings and inconsistencies that suggested they did not have a coherent framework of ideas about electromagnetism. Common errors included confusing electric and magnetic field effects, seeing field lines as indicating a flow, using cause effect reasoning in situations where it does not apply, and dealing with effects associated with the rate of change of a variable. Performance on the spatial rotation test was, however, only weakly correlated with performance on the electromagnetism questions. The findings suggest the need to develop teaching strategies that help students to visualize magnetic field patterns and effects, and assist them in integrating ideas into a more coherent framework.

Sa?lam, Murat; Millar, Robin

2006-04-01

367

Electromagnetics for Detecting Shallow Tunnels  

NASA Astrophysics Data System (ADS)

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.

Won, I.

2006-05-01

368

Power law inflation with electromagnetism  

SciTech Connect

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

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

2013-07-15

369

Electromagnetic Processing of Materials:. from the Concepts to Industrial Applications  

NASA Astrophysics Data System (ADS)

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.

Delannoy, Y.

2005-07-01

370

Advanced electromagnetic methods for aerospace vehicles  

NASA Technical Reports Server (NTRS)

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.

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

1992-01-01

371

Tracing buried pipelines using multi frequency electromagnetic  

NASA Astrophysics Data System (ADS)

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.

El-Qady, Gad; Metwaly, Mohamed; Khozaym, Ashraf

2014-06-01

372

Electromagnetic processes in the atmosphere of pulsars  

NASA Technical Reports Server (NTRS)

The work consists of two parts. The first deals with the fine structure of radio pulses. Based on kinetic theory, processes occurring in the plasma shell of a pulsar when external electromagnetic radiation is present are investigated. It is shown that electromagnetic waves cause electrons to drift relative to ions, and initiate longitudinal oscillations. A dispersion equation describing the longitudinal oscillations in magnetized plasma is derived. Conditions for excitation of oscillations are found. Correlation functions of electron density are calculated, along with the coefficients of electromagnetic wave scattering. It is shown that variations in the amplitude of pulsar pulses are associated with scintillations caused by fluctuations in the plasma electron density. The second part of the study presents a mechanism for the radio emission of pulsars. The model of a rotating and a pulsating star, a neutron star with dipolar or more complex magnetic field, is examined.

Yukhimuk, A. K.

1974-01-01

373

Electromagnetic properties of viscous charged fluids  

E-print Network

We provide a general theoretical framework to describe the electromagnetic properties of viscous charged fluids, consisting for example of electrons in certain solids or plasmas. We confirm that finite viscosity leads to multiple modes of evanescent electromagnetic waves at a given frequency, one of which is characterized by a negative index of refraction, as previously discussed in a simplified model by one of the authors. In particular we explain how optical spectroscopy can be used to probe the viscosity. We concentrate on the impact of this on the coefficients of refraction and reflection at the sample-vacuum interface. Analytical expressions are obtained relating the viscosity parameter to the reflection and transmission coefficients of light. We demonstrate that finite viscosity has the effect to decrease the reflectivity of a metallic surface, while the electromagnetic field penetrates more deeply. While on a phenomenological level there are similarities to the anomalous skin effect, the model presente...

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

2014-01-01

374

Electromagnetically driven dwarf tornados in turbulent convection  

NASA Astrophysics Data System (ADS)

Motivated by the concept of interdependency of turbulent flow and electromagnetic fields inside the spiraling galaxies, we explored the possibilities of generating a localized Lorentz force that will produce a three-dimensional swirling flow in weakly conductive fluids. Multiple vortical flow patterns were generated by combining arrays of permanent magnets and electrodes with supplied dc current. This concept was numerically simulated and applied to affect natural convection flow, turbulence, and heat transfer inside a rectangular enclosure heated from below and cooled from above over a range of Rayleigh numbers (104<=Ra<=5109). The large-eddy simulations revealed that for low- and intermediate-values of Ra, the heat transfer was increased more than five times when an electromagnetic forcing was activated. In contrast to the generally accepted view that electromagnetic forcing will suppress velocity fluctuations and will increase anisotropy of turbulence, we demonstrated that localized forcing can enhance turbulence isotropy of thermal convection compared to its neutral state.

Kenjere, Saa

2011-01-01

375

Massless Dirac Fermions in Electromagnetic Field  

E-print Network

We study the relations between massless Dirac fermions in an electromagnetic field and atoms in quantum optics. After getting the solutions of the energy spectrum, we show that it is possible to reproduce the 2D Dirac Hamiltonian, with all its quantum relativistic effects, in a controllable system as a single trapped ion through the Jaynes--Cummings and anti-Jaynes--Cummings models. Also we show that under certain conditions the evolution of the Dirac Hamiltonian provides us with Rashba spin-orbit and linear Dresselhaus couplings. Considering the multimode multiphoton Jaynes-Cummings model interacting with N modes of electromagnetic field prepared in general pure quantum states, we analyze the Rabi oscillation. Evaluating time evolution of the Dirac position operator, we determine the Zitterbewegung frequency and the corresponding oscillating term as function of the electromagnetic field.

Ahmed Jellal; Abderrahim El Mouhafid; Mohammed Daoud

2011-03-28

376

Strong Scalar QED in Inhomogeneous Electromagnetic Fields  

E-print Network

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.

Sang Pyo Kim

2008-01-22

377

Apparatus for processing electromagnetic radiation and method  

NASA Technical Reports Server (NTRS)

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.

Gatewood, George D. (Inventor)

1983-01-01

378

Drift effects on electromagnetic geodesic acoustic modes  

E-print Network

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 $f\\sim 40$ kHz oscillation observed in TCABR [Yu. K. Kuznetsov $\\textit{et al.}$, Nucl. Fusion $\\bf{52}$, 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 $\\lambda_r\\sim 25$ cm, i. e., an order of magnitude higher than the usual value for zonal flows (ZFs).

Sgalla, Rene J F

2014-01-01

379

Electromagnetic moments of quasi-stable baryons  

SciTech Connect

We address electromagnetic properties of quasi-stable baryons in the context of chiral extrapolations of lattice QCD results. For particles near their decay threshold we show that an application of a small external magnetic field changes the particle's energy in a non-analytic way. The conventional electromagnetic moments are only well-defined when the background field B satisfies |eB|/2M{sub *}<<|M{sub *}-M-m| where M{sub *} is the mass of the resonance and M, m the masses of the decay products. A direct application of this situation is the chiral extrapolation of the {Delta}(1232)-isobar electromagnetic properties. We discuss such an extrapolation of the {Delta}(1232)-isobar magnetic dipole, electric quadrupole and magnetic octupole moments by a covariant chiral effective field theory.

Ledwig, T.; Pascalutsa, V.; Vanderhaeghen, M. [Institut fuer Kernphysik, Universitaet Mainz, D-55099 Mainz (Germany); Martin-Camalich, J. [Departamento de Fisica Teorica and IFIC, Universidad de Valencia-CSIC (Spain)

2011-10-24

380

Broadband electromagnetic cloaking with smart metamaterials  

NASA Astrophysics Data System (ADS)

The ability to render objects invisible with a cloak that fits all objects and sizes is a long-standing goal for optical devices. Invisibility devices demonstrated so far typically comprise a rigid structure wrapped around an object to which it is fitted. Here we demonstrate smart metamaterial cloaking, wherein the metamaterial device not only transforms electromagnetic fields to make an object invisible, but also acquires its properties automatically from its own elastic deformation. The demonstrated device is a ground-plane microwave cloak composed of an elastic metamaterial with a broad operational band (10-12?GHz) and nearly lossless electromagnetic properties. The metamaterial is uniform, or perfectly periodic, in its undeformed state and acquires the necessary gradient-index profile, mimicking a quasi-conformal transformation, naturally from a boundary load. This easy-to-fabricate hybrid elasto-electromagnetic metamaterial opens the door to implementations of a variety of transformation optics devices based on quasi-conformal maps.

Shin, Dongheok; Urzhumov, Yaroslav; Jung, Youngjean; Kang, Gumin; Baek, Seunghwa; Choi, Minjung; Park, Haesung; Kim, Kyoungsik; Smith, David R.

2012-11-01

381

Broadband electromagnetic cloaking with smart metamaterials.  

PubMed

The ability to render objects invisible with a cloak that fits all objects and sizes is a long-standing goal for optical devices. Invisibility devices demonstrated so far typically comprise a rigid structure wrapped around an object to which it is fitted. Here we demonstrate smart metamaterial cloaking, wherein the metamaterial device not only transforms electromagnetic fields to make an object invisible, but also acquires its properties automatically from its own elastic deformation. The demonstrated device is a ground-plane microwave cloak composed of an elastic metamaterial with a broad operational band (10-12 GHz) and nearly lossless electromagnetic properties. The metamaterial is uniform, or perfectly periodic, in its undeformed state and acquires the necessary gradient-index profile, mimicking a quasi-conformal transformation, naturally from a boundary load. This easy-to-fabricate hybrid elasto-electromagnetic metamaterial opens the door to implementations of a variety of transformation optics devices based on quasi-conformal maps. PMID:23169054

Shin, Dongheok; Urzhumov, Yaroslav; Jung, Youngjean; Kang, Gumin; Baek, Seunghwa; Choi, Minjung; Park, Haesung; Kim, Kyoungsik; Smith, David R

2012-01-01

382

Gallium Electromagnetic (GEM) Thrustor Concept and Design  

NASA Technical Reports Server (NTRS)

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

Polzin, Kurt A.; Markusic, Thomas E.

2006-01-01

383

Complex geometry and pre-metric electromagnetism  

E-print Network

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.

D. H. Delphenich

2004-12-10

384

Electromagnetic Radiations as a Fluid Flow  

E-print Network

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

Daniele Funaro

2009-11-25

385

Merging electromagnetism with space-time metric  

E-print Network

In the present work, it is shown that the electromagnetism may be directly associated to the four-dimensional space-time geometry. The starting point is an analysis of the geodesic equation of general relativity where it is verified that it contains implicitly the effects of the Coulomb and the Lorentz forces. Consequently, some components of the metric tensor are identified with the components of the four-vector electromagnetic potential. Then, it is constructed a low-field equation for the electromagnetism in the same structure of the Einstein field equations for the gravitation, relating the curvature of space-time to sources of charge and current density. In this framework, all the Maxwell equations are implicit. A proof of consistency with the framework of quantum mechanics is shown.

C. A. Duarte

2014-01-29

386

Electromagnetically induced absorption via incoherent collisions  

SciTech Connect

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

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

2011-10-15

387

Electromagnetic energy momentum in dispersive media  

SciTech Connect

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

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

2011-01-15

388

Parametrically shielding electromagnetic fields by nonlinear metamaterials.  

PubMed

An analytical theory is developed for parametric interactions in metamaterial multilayer structures with simultaneous nonlinear electronic and magnetic responses and with a near-zero refractive index. We demonstrate theoretically that electromagnetic fields of certain frequencies can be parametrically shielded by a nonlinear left-handed material slab, where the permittivity and permeability are both negative. The skin depth is tunable, and even in the absence of material absorption, can be much less than the wavelength of the electromagnetic field being shielded. This exotic behavior is a consequence of the intricate nonlinear response in the left-handed materials and vanishing optical refractive index at the pump frequency. PMID:18352472

Feng, Simin; Halterman, Klaus

2008-02-15

389

Propulsion Through Electromagnetic Self-Sustained Acceleration  

E-print Network

As is known the repulsion of the volume elements of an uniformly accelerating charge or a charge supported in an uniform gravitational field accounts for the electromagnetic contribution to the charge's inertial and gravitational mass, respectively. This means that the mutual repulsion of the charge's volume elements resists its accelerated motion. Conversely, the effect of electromagnetic attraction of opposite charges results in a self-sustaining accelerated motion of the charges provided that they have been initially uniformly accelerated or supported in an uniform gravitational field. The significance of this effect is that it constitutes a possibility for altering inertia and gravitation.

Petkov, V B

1999-01-01

390

Propulsion Through Electromagnetic Self-Sustained Acceleration  

E-print Network

As is known the repulsion of the volume elements of an uniformly accelerating charge or a charge supported in an uniform gravitational field accounts for the electromagnetic contribution to the charge's inertial and gravitational mass, respectively. This means that the mutual repulsion of the volume elements of the charge produces the resistance to its accelerated motion. Conversely, the effect of electromagnetic attraction of opposite charges enhances the accelerated motion of the charges provided that they have been initially uniformly accelerated or supported in an uniform gravitational field. The significance of this effect is that it constitutes a possibility of altering inertia and gravitation.

Vesselin Petkov

1999-06-29

391

NASA GRC High Power Electromagnetic Thruster Program  

NASA Technical Reports Server (NTRS)

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

LaPointe, Michael R.; Pensil, Eric J.

2004-01-01

392

Enhanced electromagnetic emission from a dusty plasma  

NASA Astrophysics Data System (ADS)

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.

Shukla, P. K.; Stenflo, L.; Resendes, D. P.

2002-03-01

393

Electromagnetic ferrofluid-based energy harvester  

NASA Astrophysics Data System (ADS)

This Letter investigates the use of ferrofluids for vibratory energy harvesting. In particular, an electromagnetic micro-power generator which utilizes the sloshing of a ferrofluid column in a seismically-excited tank is proposed to transform mechanical motions directly into electricity. Unlike traditional electromagnetic generators that implement a solid magnet, ferrofluids can easily conform to different shapes and respond to very small acceleration levels offering an untapped opportunity to design scalable energy harvesters. The feasibility of the proposed concept is demonstrated and its efficacy is discussed through several experimental studies.

Bibo, A.; Masana, R.; King, A.; Li, G.; Daqaq, M. F.

2012-06-01

394

Device and method for redirecting electromagnetic signals  

DOEpatents

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

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

1999-01-01

395

Phenomenology of the Deuteron Electromagnetic Form Factors  

E-print Network

A rigorous extraction of the deuteron charge form factors from tensor polarization data in elastic electron-deuteron scattering, at given values of the 4-momentum transfer, is presented. Then the world data for elastic electron-deuteron scattering is used to parameterize, in three different ways, the three electromagnetic form factors of the deuteron in the 4-momentum transfer range 0-7 fm^-1. This procedure is made possible with the advent of recent polarization measurements. The parameterizations allow a phenomenological characterization of the deuteron electromagnetic structure. They can be used to remove ambiguities in the form factors extraction from future polarization data.

TheJLAB t20 collaboration; D. Abbott

2000-02-04

396

Electromagnetically induced transparency for x-rays.  

SciTech Connect

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-13s and 1s-13p ({approx}800 nm). The minimum laser intensity required to observe electromagnetically induced transparency is of the order of 1012 W/cm2. 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.

Buth, C.; Santra, R.; Young, L.; Chemistry

2007-06-22

397

Phenomenology of the deuteron electromagnetic form factors  

SciTech Connect

A rigorous extraction of the deuteron charge form factors from tensor polarization data in elastic electron-deuteron scattering, at given values of the 4-momentum transfer, is presented. Then the world data for elastic electron-deuteron scattering is used to parameterize, in three different ways, the three electromagnetic form factors of the deuteron in the 4-momentum transfer range 0-7 fm. This procedure is made possible with the advent of recent polarization measurements. The parameterizations allow a phenomenological characterization of the deuteron electromagnetic structure. They can be used to remove ambiguities in the form factors extraction from future polarization data.

David Abbott; Abdellah Ahmidouch; H. Anklin; J. Arvieux; James P. Ball; Shelton Beedoe; Elizabeth Beise; Louis Bimbot; Werner Boeglin; Herbert Breuer; Roger Carlini; Nicholas Chant; Samuel Danagoulian; K. Dow; Jean-Eric Ducret; Jim Dunne; Lars Ewell; L. Eyraud; C. Furget; Michel Garcon; Ron Gilman; Charles Glashausser; Paul Gueye; Kenneth Gustafsson; Kawtar Hafidi; A. Honegger; J. Jourdan; Serge Kox; Gerfried Kumbartzki; L. Lu; Allison Lung; Pete Markowitz; Justin McIntyre; David Meekins; F. Merchez; Joseph Mitchell; R. Mohring; S. Mtingwa; H. Mrktchyan; D. Pitz; Liming Qin; Ronald Ransome; J.-S. R'eal; Philip Roos; Paul Rutt; Reyad Sawafta; Stepan Stepanyan; Raphael Tieulent; E. Tomasi-Gustafsson; William Turchinetz; K. Vansyoc; J. Volmer; E. Voutier; Claude Williamson; Stephen Wood; Chen Yan; Jianguo Zhao; W. Zhao

2000-04-01

398

Phenomenology of the deuteron electromagnetic form factors  

SciTech Connect

A rigorous extraction of the deuteron charge form factors from tensor polarization data in elastic electron-deuteron scattering, at given values of the 4-momentum transfer, is presented. Then the world data for elastic electron-deuteron scattering is used to parameterize, in three different ways, the three electromagnetic form factors of the deuteron in the 4-momentum transfer range 0-7 fm. This procedure is made possible with the advent of recent polarization measurements. The parameterizations allow a phenomenological characterization of the deuteron electromagnetic structure. They can be used to remove ambiguities in the form factors extraction from future polarization data.

David Abbott; Abdellah Ahmidouch; H. Anklin; J. Arvieux; James P. Ball; Shelton Beedoe; Elizabeth Beise; Louis Bimbot; Werner Boeglin; Herbert Breuer; Roger Carlini; Nicholas Chant; Samuel Danagoulian; K. Dow; Jean-Eric Ducret; Jim Dunne; Lars Ewell; L. Eyraud; C. Furget; Michel Garcon; Ron Gilman; Charles Glashausser; Paul Gueye; Kenneth Gustafsson; Kawtar Hafidi; A. Honegger; J. Jourdan; Serge Kox; Gerfried Kumbartzki; L. Lu; Allison Lung; Pete Markowitz; Justin McIntyre; David Meekins; F. Merchez; Joseph Mitchell; R. Mohring; S. Mtingwa; H. Mrktchyan; D. Pitz; Liming Qin; Ronald Ransome; J.-S. R'eal; Philip Roos; Paul Rutt; Reyad Sawafta; Stepan Stepanyan; Raphael Tieulent; E. Tomasi-Gustafsson; William Turchinetz; K. Vansyoc; J. Volmer; E. Voutier; Claude Williamson; Stephen Wood; Chen Yan; Jianguo Zhao; W. Zhao

2000-02-25

399

Forces in electromagnetic field and gravitational field  

E-print Network

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.

Zihua Weng

2008-06-21

400

Effects of Electromagnetic Field on Gravitational Collapse  

E-print Network

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.

M. Sharif; G. Abbas

2009-05-16

401

Electromagnetic wave collapse in a radiation background  

E-print Network

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.

Mattias Marklund; Gert Brodin; Lennart Stenflo

2003-05-15

402

Scanning evanescent electro-magnetic microscope  

DOEpatents

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.

Xiang, Xiao-Dong (Alameda, CA); Gao, Chen (Anhui, CN); Schultz, Peter G. (La Jolla, CA); Wei, Tao (Sunnyvale, CA)

2003-01-01

403

Program For Displaying Computed Electromagnetic Fields  

NASA Technical Reports Server (NTRS)

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.

Hom, Kam W.

1995-01-01

404

Scanning evanescent electro-magnetic microscope  

DOEpatents

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.

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

2001-01-01

405

Electromagnetic Waves in the De Sitter Space  

E-print Network

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.

V. S. Otchik; V. M. Red'kov

2010-01-24

406

Electromagnetic waves, gravitational coupling and duality analysis  

E-print Network

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

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

2005-10-27

407

Electromagnetic Observables in Few-Nucleon Systems  

E-print Network

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

Sonia Bacca

2012-10-10

408

Duality in Off-Shell Electromagnetism  

E-print Network

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.

Martin Land

2006-03-21

409

Classical quarks in dual electromagnetic fields  

E-print Network

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.

Harry Schiff

2010-12-05

410

Electromagnetic WavesElectromagnetic Waves In this chapter we will review selected properties of electromagnetic waves since  

E-print Network

of electromagnetic waves since radar involves the transmission, propagation and scattering of EM waves by various dielectric materials. Electric Field--charged bodies create an electric field which in turn constitutes material. This movement of electrons constitutes an electric current. Hence magnetic fields are associated

Rutledge, Steven

411

1. Electromagnetic Compatibility Abstract --This paper presents experimental and numerical  

E-print Network

1. Electromagnetic Compatibility Abstract -- This paper presents experimental and numerical results concerning Transmission Line Excited Chamber (TLEC). This chamber is an alternative for electromagnetic compatibility tests, notably radiated immunity. The E-field profile, frequency response, SWR, and S parameters

Paris-Sud XI, Université de

412

Micro-electromagnetic formation flight of satellite systems  

E-print Network

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) ...

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

2007-01-01

413

Passive electromagnetic damping device for motion control of building structures  

E-print Network

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 ...

Palomera-Arias, Rogelio, 1972-

2005-01-01

414

Understanding Electromagnetic Radiation from an Accelerated William E. Baylis  

E-print Network

Understanding Electromagnetic Radiation from an Accelerated Charge William E. Baylis Physics and solid theoretical underpinnings, the formation of electromagnetic (EM) radiation by accelerating charges is still a source of wonder if not bewilderment. The con- ceptual understanding of how radiation

Hart, Gus

415

Propagation Analysis of Electromagnetic Waves: Application to Auroral Kilometric Radiation  

E-print Network

12 Propagation Analysis of Electromagnetic Waves: Application to Auroral Kilometric Radiation Kilometric Radiation (AKR). We give a brief tutorial description of the background considerations useful words: Electromagnetic waves in plasmas, direction finding, wave distribution function, auroral

Santolik, Ondrej

416

On the gravitational fields created by the electromagnetic waves  

E-print Network

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.

A. Loinger; T. Marsico

2011-06-11

417

Sensitivity of electromagnetic waves to a heterogeneous bianisotropic structure  

E-print Network

Sensitivity of electromagnetic waves to a heterogeneous bianisotropic structure Ludek Klimes for the scattered Gaussian packets without derivation. The derivation for the electromagnetic waves is analogous of a generally heterogeneous bianisotropic structure manifest themselves in the wave field, and which

Cerveny, Vlastislav

418

Electromagnetic Light in Medium of Polarized Atoms $^3$He  

E-print Network

First, it is predicted that polarized atoms $^3$He increase a value of speed electromagnetic waves. This reasoning implies that the velocity of electromagnetic waves into gas consisting of polarized atoms $^3$He is rather than one in vacuum.

V. N. Minasyan

2008-09-01

419

NEAR-SURFACE CONTROLLED-SOURCE ELECTROMAGNETIC INDUCTION  

E-print Network

NEAR-SURFACE CONTROLLED-SOURCE ELECTROMAGNETIC INDUCTION: BACKGROUND AND RECENT ADVANCES MARK E The controlled-source electromagnetic (CSEM) induction method is emerging as a leading geophysical technique

Meju, Max

420

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

E-print Network

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

US Army Corps of Engineers

421

Parameters for an electromagnetic naval railgun  

Microsoft Academic Search

The United States Navy is considering the electromagnetic (EM) railgun as a future candidate for long-range shore bombardment missions. This brief study evaluates the gun and the pulsed power supply for this application. Approximate parameters are derived for a notional system that includes the projectile, launch package, railgun, and pulsed power components

Ian R. McNab; Scott Fish; Francis Stefani

2001-01-01

422

Solid-projectile helical coil electromagnetic launcher  

Microsoft Academic Search

Helical coil electromagnetic launchers (HCEMLs) can operate at significantly lower currents and higher efficiency in comparison to conventional railgun and induction coilgun launchers. The HCEMLs versatility is due, in part, to its large inductance gradient which is typically 2 to 3 orders of magnitude greater than conventional railguns and can be tailored to practically any value in that range. The

T. G. Engel; J. M. Neri; M. J. Veracka

2007-01-01

423

Electromagnetic stirring of aluminium-silicon alloys  

Microsoft Academic Search

A laboratory-scale electromagnetic stirrer was designed, constructed and tested on two aluminium-silicon alloys with silicon contents of seven and twenty mass per cent. The effect of stirring intensity on the structure of the hypoeutectic alloy was studied and also thermal analysis was performed. For the case of the hypereutectic alloy, the distribution of silicon was determined. The results demonstrate that

D. A. Currey; C. A. Pickles

1988-01-01

424

-59 -llc1 LIGHTNING ELECTROMAGNETIC FIELDS  

E-print Network

- 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

Florida, University of

425

Multirate modeling scheme for electromagnetic transients calculation  

Microsoft Academic Search

In this paper, a multirated scheme based on filter banks is proposed for networks modeling in electromagnetic transient calculation. The basic idea is to convolve in the sub-bands using models of different complexity for the lowand high-frequency range in order to reduce the overall computational complexity. The proposed scheme is intended to be primarily used in real time calculation algorithms,

Humberto Zini; Giuseppe Ratta

2004-01-01

426

Electromagnetic launch by linear quadrupole field  

Microsoft Academic Search

This paper presents a novel electromagnetic launch concept based on a DC linear quadrupole field with no axial component. The proposed design enables contact-free power transfer to the launch vehicle while removing the need of switching power or AC induction. Passive damping windings are proposed to provide radial stability during launch. The 6-DOF dynamics of the launch vehicle, including the

Dengfeng Li; Rainer Meinke; Daniel Kirk; Hector Gutierrez

2008-01-01

427

THE ELECTROMAGNETIC PINCH EFFECT FOR SPACE PROPULSION  

Microsoft Academic Search

The phenomenon of the electromagnetic pinch effect is used to accelerate ; ionized gases for space propulsion. Electrical energy, initially stored in ; capacitors, is discharged across two nozzle shaped electrodes wherein the radial ; pinch is converted to axial motion of the effected gases instead of confinement ; at the axis. The gas dynamics of a pinch using the

A. E. Kunen; W. McIlroy

1959-01-01

428

Conference on electromagnetic guns and launchers, 1980  

Microsoft Academic Search

Proceedings includes 31 papers dealing with the physical principles and engineering technology associated with the development of electromagnetic propulsion, with emphasis on its use for guns, launchers as well as other military equipment. Topics covered include: rail guns, projectiles, mass accelerators, electric motors and generators, nuclear reactors, superconducting devices, plasma acceleration and confinement, traveling magnetic waves, aerospace propulsion, space shuttles,

Anon

1982-01-01

429

Electromagnetic propulsion: drag and erosion modeling  

Microsoft Academic Search

Railgun electromagnetic accelerators are currently being designed for hypervelocity projectile launch in equation of state impact experiments. Launcher development is proceeding in successive stages of increased acceleration and velocity with a goal of launching sabot-supported 1 g projectiles at speeds near 100 km\\/s. The railgun utilizes Lorentz force produced by the current in an electrically conducting moving armature interacting with

Buckingham

1980-01-01

430

Electromagnetic launchers: Background and the MRL program  

Microsoft Academic Search

Electromagnetic launchers are studied. These have potential applications in weaponry, controlled thermonuclear fusion, space launch, advanced industrial processes, equation of state research, generation of intense magnetic fields and as facilities for a wide range of studies in penetration mechanics, detonation, and warheads.

Y. C. Thio

1982-01-01

431

Transition electromagnetic fields in particle physics  

Microsoft Academic Search

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

Abdus Salam; J. Strathdee

1975-01-01

432

Charging Ahead: An Introduction to Electromagnetism.  

ERIC Educational Resources Information Center

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,

Shafer, Larry E.

433

MATHEMA: A Constructivist Enviroment for Electromagnetism Learning  

Microsoft Academic Search

In this paper we describe the Web-based adaptive educational hypermedia system called MATHEMA. In general, the MATHEMA is a learning system that dynamically generates courses in electromagnetism according to studentspsila learning goal, knowledge level, performance, learning style, abstract or concrete dimension of learning style, preference for visual and\\/or verbal feedback, preference for the kind of navigation, and preference of using

Alexandros Papadimitriou; Georgios Gyftodimos; Maria Grigoriadou

2009-01-01

434

Electromagnetic Compatibility of Matrix Converter System  

Microsoft Academic Search

Abstract. The presented paper ,deals with matrix converters pulse width modulation strategies design with emphasis on the ,electromagnetic compatibility. Matrix converters provide an all-silicon solution to the problem of converting AC power from one frequency to another, offering almost all the features required of an ideal static frequency changer. They possess many ,advantages compared to the conventional voltage or current

Ji? Lettl; Stanislav Flgl

435

ADJOINT BASED SAMPLING METHODS FOR ELECTROMAGNETIC SCATTERING  

E-print Network

ADJOINT BASED SAMPLING METHODS FOR ELECTROMAGNETIC SCATTERING H. EGGER, M. HANKE, C. SCHNEIDER, J of sampling methods, based on solutions of certain adjoint problems. This adjoint ap- proach does not require and all dipole direc- tions simultaneously; thus several limitations of standard sampling methods

Hanke-Bourgeois, Martin

436

Psychological Studies in Nonionizing Electromagnetic Energy Research  

Microsoft Academic Search

Research on nonionizing electromagnetic (NIEM) energy has focused on potential hazards, and to a lesser degree beneficial applications, of radiofrequency (RF) fields and extremely low frequency (ELF) fields. The history of research on the potential biological effects of NIEM contains many psychological investigations. These psychological investigations were conducted primarily in the discipline of biopsychology and included interdisciplinary cooperation with engineering,

Mary Ellen Oconnor

1993-01-01

437

Electromagnetic fields: low dose exposure, current update  

Microsoft Academic Search

Objectives: The controversial discussion of low-dose electromagnetic field (EMF) effects on human health derives from a lack of knowledge of the mechanism of action and proven results of cellular, animal and human experiments. The paper gives an overview of the current results of scientific research. Methods: Review based on the legal measurements of the EU parliament, the ICNIRP guidelines, the

O. Jahn

2000-01-01

438

Electromagnetic Energy Absorption within Extensive Impedance Structures  

Microsoft Academic Search

The filamentary-source excitation problems are considered with regards to extensive cavities and plane structures with surface impedance specified. The solutions are based on rigorous approaches. Particular features of the electromagnetic field absorption in such structures are shown. The choice and optimal values of impedance are proposed to ensure the fastest field attenuation when going through a duct with impedance walls.

Andrey Lagarkov; Vladimir Kisel

439

An omnidirectional electromagnetic absorber made of metamaterials  

Microsoft Academic Search

In a recent theoretical work by Narimanov and Kildishev (2009 Appl. Phys. Lett. 95 041106) an optical omnidirectional light absorber based on metamaterials was proposed, in which theoretical analysis and numerical simulations showed that all optical waves hitting the absorber are trapped and absorbed. Here we report the first experimental demonstration of an omnidirectional electromagnetic absorber in the microwave frequency.

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

2010-01-01

440

An Electromagnetic GL Double Layered Cloak  

Microsoft Academic Search

In this paper, we propose a new electromagnetic (EM) GL double layered cloak. The GL double layered cloak is consist of two sphere annular layers, $R_1 \\\\le r \\\\le R_2$ and $R_2 \\\\le r \\\\le R_3$. Two type cloak materials are proposed and installed in the each layer, respectively. The outer layer cloak of the GL double layered cloak has

Ganquan Xie; Jianhua Li; Feng Xie; Lee Xie

2009-01-01

441

Electromagnetic Absorption by Metamaterial Grating System  

Microsoft Academic Search

Total absorption of electromagnetic waves is demonstrated in a system composed of zero-order metamaterial grating and rearward metamaterial wall. The grating and the wall are separated by an air gap. Two mechanisms are shown to account for this absorption. The flrst one is due to the existence of standing waves in both the grooves of the grating and the air

Xiaobing Cai; Gengkai Hu

2008-01-01

442

Antenna design using Transformation Electromagnetics (TEM)  

Microsoft Academic Search

We present two different points of approaches to a class of antenna designs, based on two variations of the Transformation Electromagnetics (T-EM) approach, both of which have been introduced recently in the literature. The first of these addresses the antenna and absorber design problems from the Transformation Optics viewpoint, while the second looks at the same problem from a Field

Raj Mittra; King Fahd

2011-01-01

443

An omnidirectional electromagnetic absorber made of metamaterials  

Microsoft Academic Search

In a recent theoretical work by Narimanov and Kildishev (2009 Appl. Phys. Lett.95 041106) an optical omnidirectional light absorber based on metamaterials was proposed, in which theoretical analysis and numerical simulations showed that all optical waves hitting the absorber are trapped and absorbed. Here we report the first experimental demonstration of an omnidirectional electromagnetic absorber in the microwave frequency. The

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

2010-01-01

444

Electromagnetic waves in absorbing uniaxial metamaterials  

Microsoft Academic Search

Features of the polarization, energy fluxes of proper inhomogeneous electromagnetic waves in a layer of absorbing uniaxial negative index metamaterial, and an exact solution of the corresponding boundary problem are investigated. A comparative analysis and modeling of optical properties of anisotropic conventional media and metamaterials is carried out. Conditions and possible advantages of a controlled transformation of the radiation characteristics

Evgenii Starodubtsev

2007-01-01

445

Measurements of Low Frequency Electromagnetic Instabilities  

Microsoft Academic Search

Very low frequency, below 10 kHz, weak, electromagnetic instabilities are difficult to measure in plasmas because the typical diagnostic, a magnetic sense coil, has a frequency dependent sensitivity. The sensitivity of a magnetic sense coil can be increased by increasing the number of turns on the coil, but at the expense of size and high frequency response. As an alternative

Brendan McGeehan; Anna Zaniewski; Costel Biloiu; Earl Scime

2003-01-01

446

On the electromagnetic detection of gravitational waves  

Microsoft Academic Search

Braginsky and Mensky have described a novel gravitational wave detector based on a special gravitational-electromagnetic resonance in an annular waveguide. Their analysis is based on geometrical optics. If the configuration is analyzed as a perturbed boundary-value problem, however, no special resonance is evident. Nor does a more general cavity exhibit such a resonance. This paper concludes with a moral: When

Ralph Baierlein

1976-01-01

447

The Electromagnetic Spectrum: Wavelength and Energy  

NSDL National Science Digital Library

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

448

Electromagnetic Spectrum: Distribution of Radiant Energies  

NSDL National Science Digital Library

This item is a beginning tutorial on the electromagnetic spectrum designed for students of introductory physics. It provides multiple plots of the spectrum to aid users in understanding various EM spectrum classifications. This item is part of a larger tutorial on the topic of Remote Sensing, sponsored by the NASA Goddard Program office.

Short, Nicholas M.

2008-06-12

449

Progress in Electromagnetic Launch Science and Technology  

Microsoft Academic Search

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

Harry D. Fair

2007-01-01

450

Calibrating Accelerometers Using an Electromagnetic Launcher.  

National Technical Information Service (NTIS)

A Pulse Forming Network (PFN), Helical Electromagnetic Launcher (HEML), Command Module (CM), and Calibration Table (CT) were built and evaluated for the combined ability to calibrate an accelerometer. The PFN has a maximum stored energy of 19.25 kJ bank a...

E. Timpson

2012-01-01

451

Quantized electromagnetic tornado in pulsar vacuum gap  

E-print Network

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.

Kontorovich, V M

2009-01-01

452

Alternative derivation of electromagnetic cloaks and concentrators  

Microsoft Academic Search

Beginning with a straightforward formulation of electromagnetic 'cloaking' that reduces to a boundary value problem involving a single Maxwell first-order differential equation, explicit formulae for the relative permittivity permeability dyadic and fields of spherical and circular cylindrical annular cloaks are derived in terms of general compressed radial coordinate functions. The general formulation is based on the requirements that the cloaking

A. D. Yaghjian; Stefano Maci

2008-01-01

453

Electromagnetic driving units for complex microrobotic systems  

NASA Astrophysics Data System (ADS)

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.

Michel, Frank; Ehrfeld, Wolfgang; Berg, Udo; Degen, Reinhard; Schmitz, Felix

1998-10-01

454

Electromagnetic Wave Interactions with a Metamaterial Cloak  

Microsoft Academic Search

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

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

2007-01-01

455

Generalized Electromagnetic fields in Chiral Medium  

E-print Network

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

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

2007-03-12

456

Relativistic Motion in a Constant Electromagnetic Field  

E-print Network

For a relativistic charged particle moving in a constant electromagnetic field, its velocity 4-vector has been well studied. However, despite the fact that both the electromagnetic field and the equations of motion are purely real, the resulting 4-velocity is seemingly due to a complex electromagnetic field. This work shows that this is not due to some complex formalism used (such as Clifford algebra) but is intrinsically due to the fact that the $o(3,1)$ Lie algebra of the Lorentz group is equivalent to two commuting complex $su(2)$ algebras. Expressing the complex $su(2)$ generators in terms of the boost and rotation operators then naturally introduces a complex electromagnetic field. This work solves the equation of motion not as a matrix equation, but as an operator evolution equation in terms of the generators of the Lorentz group. The factorization of the real evolution operator into two commuting complex evolution operators then directly gives the time evolution of the velocity 4-vector without any reference to an intermediate field.

Siu A. Chin

2008-09-04

457

Electromagnetic interactions in Halo Effective Field Theory  

E-print Network

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.

Renato Higa

2010-01-04

458

Electromagnetic Scattering From Foliage Camouflaged Complex Targets  

Microsoft Academic Search

In this paper, a hybrid target-foliage model based on existing electromagnetic techniques is developed to investigate the scattering behavior of hard targets embedded inside a forest canopy at high frequencies. The proposed model is composed of two basic scattering models, one for foliage and the other for the hard targets. The connection between these two models, which accounts for the

Mojtaba Dehmollaian; Kamal Sarabandi

2006-01-01

459

CONTINUUM ELECTROMAGNETIC RADIATION FROM SOLAR FLARES  

Microsoft Academic Search

Continuum electromagnetic radiation from solar flares is discussed in ; terms of the energy loss processes of electrons in the solar atmosphere. It is ; shown that it is possible to attribute the continuum radiation both at radio ; frequencies and at visible frequencies to synchrotron radiation by exponential ; rigidity distributions of electrons. (auth);

W. A. Stein; E. P. Ney

1963-01-01

460

Out-of-equilibrium electromagnetic radiation  

E-print Network

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.

Julien Serreau

2003-10-03

461

Electromagnetic Radiation and Motion of Real Particle  

E-print Network

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.

Jozef Klacka

2000-08-31

462

Influence of Absorbers on the Electromagnetic Radiation  

E-print Network

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.

Neil V. Budko

2007-12-05

463

The wave structure of monochromatic electromagnetic radiation  

Microsoft Academic Search

The paper considers a general field of electromagnetic waves of a single frequency and identifies the salient structurally stable features of the three-dimensional pattern of polarization. The approach is geometrical rather than analytical, and it differs from previous treatments of this kind by being applicable even when the constituent plane waves are travelling in all directions. Lines and surfaces exist

J. F. Nye; J. V. Hajnal

1987-01-01

464

Electromagnetics from Simulation to Optimal Design  

E-print Network

machines · Metamaterials from 50Hz to optics: ,,electrosmog" shielding, radar absorbers, heat protection in a sapphire tube OpenMaX simulations Fabrication and measurement (MPI Germany) #12;6 Radar absorbing structures (July 1-3, 2013, ETZ E6) #12;3 IFH research · Computational electromagnetics and optics: FEM, MMP

Lang, Annika

465

Pulsing electromagnetic fields induce cellular transcription  

Microsoft Academic Search

Weak, pulsing electromagnetic fields can modify biological processes. The hypothesis that responses to such induced currents depend on pulse characteristics was evaluated by using transcription as the target process. Two pulses in clinical use, the repetitive single pulse and the repetitive pulse train, were tested. These pulses produced different results from each other and from controls when transcription in dipteran

R. Goodman; C. A. Bassett; A. S. Henderson

1983-01-01

466

Calculating Electromagnetic Fields Of A Loop Antenna  

NASA Technical Reports Server (NTRS)

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.

Schieffer, Mitchell B.

1987-01-01

467

Projecting Discretized Electromagnetic Fields with Unstructured Grids.  

National Technical Information Service (NTIS)

A new method for projecting discretized electromagnetic fields on one unstructured grid to another grid is presented in this paper. Two examples are used for studying the errors of different projection methods. The analysis shows that the new method is ve...

A. Candel, A. Kabe, L. Q. Candel, Z. Li

2008-01-01

468

The behavior of electromagnetic fields at edges  

Microsoft Academic Search

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

J. Meixner

1972-01-01

469

Transformation media that rotate electromagnetic fields  

Microsoft Academic Search

The authors suggest a way to manipulate electromagnetic waves by introducing a rotation mapping of coordinates that can be realized by a specific transformation of the permittivity and permeability of a shell surrounding an enclosed domain. Inside the enclosed domain, the information from the outside will appear as if it is coming from a different angle. Numerical simulations were performed

Huanyang Chen; C. T. Chan

2007-01-01

470

Relativistic particle motion in nonuniform electromagnetic waves  

NASA Technical Reports Server (NTRS)

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

Schmidt, G.; Wilcox, T.

1973-01-01

471

Scattering of Electromagnetic Waves, Theories and Applications  

Microsoft Academic Search

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

Leung Tsang; Jin Au Kong; Kung-Hau Ding

2000-01-01

472

Special relativity in the electromagnetic wave  

E-print Network

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.

Bernhard Rothenstein; Ioan Damian

2005-04-27

473

Modeling of electromagnetic fields reflected by runes  

Microsoft Academic Search

The technique of computer design of the parameters of the electromagnetic field reflected by the FEHU rune is shown. The geometrical optics techniques are used for the exact analysis of the phase vibrations reflected by the rune. We demonstrate influencing of the Fehu rune on same bio-object parameters, which were used as the detector of action.

O. P. Maksimyak; L. Y. Podkamen

2007-01-01

474

Electromagnetic field interactions with biological systems.  

PubMed

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 us, as 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. PMID:8440406

Frey, A H

1993-02-01

475

Development of a rotary electromagnetic microgenerator  

Microsoft Academic Search

This study presents the development of an in-plane rotary electromagnetic microgenerator, which consists mainly of a multilayer planar copper (Cu) microcoil and a multipolar hard magnet made of NdFeB, the whole volume of which is approximately 5 5 2 mm3. The study focuses on the design and manufacturing required to obtain a high power generation output, and an

C. T. Pan; T. T. Wu

2007-01-01

476

Electromagnetic properties of viscous charged fluids  

E-print Network

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

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

2014-06-05

477

221A Lecture Notes Electromagnetic Couplings  

E-print Network

221A Lecture Notes Electromagnetic Couplings 1 Classical Mechanics The coupling of the vector potential, d dt A(x(t), t) = vj jAi + Ai . (23) 1.3 A Different Unit System In quantum mechanics electric currents, r the distance between them and l the length for which the force acts. Note that only

Murayama, Hitoshi

478

221A Lecture Notes Electromagnetic Couplings  

E-print Network

221A Lecture Notes Electromagnetic Couplings 1 Classical Mechanics The coupling potential, d dt A(x(t), t) = vj jAi + Ai . (23) 3 #12;1.3 Gaussian System In quantum mechanics (or potential by c. Note that the Gaussian unit is used conventionally together with the cgs system

Murayama, Hitoshi

479

Advanced Helicopter Electromagnetics: industry, government and university  

Microsoft Academic Search

The Advanced Helicopter Electromagnetics (AHE) was initiated at Arizona State University on January 1, 1990, to address research needs on developing analytical and measurement methods for helicopter EM applications. The AHE program is a coalition of research and education efforts supported by aerospace industry, federal government agencies and state government. The objective of the AHE program was to develop analytical

Constantine A. Balanis; Weimin Sun; Panayiotis A. Tirkas; George C. Barber

1994-01-01

480

The ATLAS liquid-argon electromagnetic calorimeter  

NASA Astrophysics Data System (ADS)

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.

Zolnierowski, Yves; Atlas Collaboration

1996-12-01

481

Electromagnetic compatibility design guideline for STADAN  

NASA Technical Reports Server (NTRS)

Procedures for achieving electromagnetic compatibility in electronic and electrical equipment for aerospace ground stations are investigated. The application of shielding theory to good design is treated and standards of good practice are outlined for bonding, grounding, wiring, and cabling. Some aspects of filter design are explained, and suggestions are given for the application of filters to electronic and electrical equipment.

Cowdell, R. B.; Hill, J. S.; Senn, J. C.; Shifman, J. C.; Skaggs, J. W.

1971-01-01

482

Electromagnetic Composites at the Compton Scale  

E-print Network

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.

Frederick J. Mayer; John R. Reitz

2011-09-10

483

Line geometry and electromagnetism I: basic structures  

E-print Network

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.

D. H. Delphenich

2013-09-11

484

Electromagnetic Siegert states for periodic dielectric structures  

E-print Network

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

Friends R. Ndangali; Sergei V. Shabanov

2011-08-09

485

Electromagnetic optimization exploiting aggressive space mapping  

Microsoft Academic Search

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

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

1995-01-01

486

Energy Mental Models: Mechanics through Electromagnetism  

NSDL National Science Digital Library

We investigated students' mental models for energy, and changes in these models in going from mechanics to electromagnetism contexts. We interviewed students in a two-semester calculus-based physics course. Our research design included semi-structured interviews with demonstration. Based on our findings in the interviews we are developing a first version of an 'Energy Mental Model Inventory.'

Itza-Ortiz, Salomon F.; Lawrence, Benjamin; Zollman, Dean A.

2005-11-02

487

Electromagnetism Adapted for Life Science Students  

ERIC Educational Resources Information Center

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)

Gurr, F. M.; And Others

1974-01-01

488

The Good, the Bad and the Electromagnet  

NSDL National Science Digital Library

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

STARS GK-12 Program,

489

Relations Among Systems of Electromagnetic Equations  

ERIC Educational Resources Information Center

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.

page, Chester H.

1970-01-01

490

Electromagnetic fields in bone repair and adaptation  

NASA Astrophysics Data System (ADS)

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

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

1995-01-01

491

On the Laws of Electromagnetic Induction  

E-print Network

The Faraday-Ampere laws of electro-magnetic induction are formulated in terms of plain and twisted differential forms, taking in due account the body motion in terms of Lie time-derivatives. Covariance of Lie derivatives with respect to arbitrary relative motions, and Galilei invariance of the electro-magnetic fields, imply Galilei invariance of the induction laws, contrary to most claims in literature. A noteworthy outcome of the theory is the conclusion that the so called Lorentz force on a charged particle is not an additional law of electromagnetism, but rather, when corrected by a factor one-half, a contribution to the electric field evaluated, according to Faraday law, by an observer testing a translating charged body crossing a region of uniform magnetic field. The formulation of the laws of electromagnetism in the four dimensional classical space-time, by stating the observer-dependent splitting for bodies in motions, provides a proof of Galilei invariance of all the electric and magnetic fields involved in the analysis.

Giovanni Romano

2011-05-17

492

Electromagnetic interference analysis of magnetic resistance sensors inside a projectile under complex electromagnetic environments  

NASA Astrophysics Data System (ADS)

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.

Guo, Qingwei; Gao, Min; Lu, Zhicai; Yang, Peijie

2013-03-01

493

Comparison of Commercial Electromagnetic Interface Test Techniques to NASA Electromagnetic Interference Test Techniques  

NASA Technical Reports Server (NTRS)

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.

Smith, V.; Minor, J. L. (Technical Monitor)

2000-01-01

494

The Darwin model as a tool for electromagnetic plasma simulation  

NASA Technical Reports Server (NTRS)

The Darwin model of electromagnetic interaction is presented as a self-consistent theory, and is shown to be an excellent approximation to the Maxwell theory for slow electromagnetic waves. Since the fast waves of the Maxwell theory are absent, it is convenient for use in the computer simulation of the electromagnetic dynamics of nonrelativistic plasma.

Kaufman, A. N.; Rostler, P. S.

1970-01-01

495

Nonlinear Electromagnetic Waves in a Strongly Magnetized Plasma  

Microsoft Academic Search

An electromagnetic wave propagating through a highly magnetized plasma experiences nonlinear effects arising from its interaction with both the plasma and the QED vacuum. We numerically explore the nonlinear behaviour of these waves using a model in which the background field and electromagnetic waves are treated nonperturbatively and can be arbitrarily strong. It is expected that electromagnetic waves commonly form

Dan Mazur; J. S. Heyl

2010-01-01

496

Determining and controlling the electromagnetic environment for Space Station Freedom  

NASA Technical Reports Server (NTRS)

Critical issues facing the SSF electromagnetic compatibility community are discussed focusing on effective utilization of SSF resources to perform overall SSF verification. Attention is also given to management and phases of an Electromagnetic Environment Effects Control Program (EEECP) aimed at producing an electromagnetically compatible station.

Pearson, S. D.; Mccollum, M. B.

1993-01-01

497

Electromagnetic Interference and Safety in Wireless Networks: A Statistical Approach  

E-print Network

, K1N 6N5 E-mail: sergey.loyka@ieee.org Vladimir Mordachev Electromagnetic Compatibility LaboratoryElectromagnetic Interference and Safety in Wireless Networks: A Statistical Approach Sergey Loyka E-mail: emc@bsuir.by Abstract- Statistical properties of electromagnetic environment in wireless

Loyka, Sergey

498

Soft Tempest: Hidden Data Transmission Using Electromagnetic Emanations  

E-print Network

electromagnetic compatibility (EMC) and radio frequency in- terference (RFI) testing. Some tests involve longSoft Tempest: Hidden Data Transmission Using Electromagnetic Emanations Markus G. Kuhn and Ross J on a computer to control the electromagnetic radiation it transmits. This can be used for both attack

Kuhn, Markus

499

Manipulating the loss in electromagnetic cloaks for perfect wave absorption  

Microsoft Academic Search

We examine several ways to manipulate the loss in electromagnetic cloaks, based on transformation electromagnetics. It is found that, by utilizing inherent electric and magnetic losses of metamaterials, perfect wave absorption can be achieved based on several popular designs of electromagnetic cloaks. A practical implementation of the absorber, consisting of ten discrete layers of metamaterials, is proposed. The new devices

Christos Argyropoulos; Efthymios Kallos; Yan Zhao; Yang Hao

2009-01-01

500

Remote sensing of earth's resources using broadband electromagnetic response  

Microsoft Academic Search

It is shown that the sun is a source of broadband electromagnetic waves. The electromagnetic wave generation and their interaction with material media is shown to play an important role in remote sensing studies. The physical parameters that characterise earth's resources govern the electromagnetic wave response and is shown to enhance the potentiality of active and passive remote sensing. Importance

R. N. Singh

1993-01-01