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Note: This page contains sample records for the topic "magnetic field charged" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


1

Magnetic Charge and Quantum Field Theory  

Science Journals Connector (OSTI)

A quantum field theory of magnetic and electric charge is constructed. It is verified to be relativistically invariant in consequence of the charge quantization condition eg?c=n, an integer. This is more restrictive than Dirac's condition, which would also allow half-integral values.

Julian Schwinger

1966-04-29T23:59:59.000Z

2

Motion of charged particles in ABC magnetic fields Alejandro Luque #  

E-Print Network (OSTI)

Motion of charged particles in ABC magnetic fields Alejandro Luque # Departament de Matemâ?? atica consequences of our study are the existence of confinement regions of charges near some magnetic lines, magnetic field, Hamiltonian dynamical system, el­ liptic equilibrium point, quasi­periodic solution

3

CHARGED TORI IN SPHERICAL GRAVITATIONAL AND DIPOLAR MAGNETIC FIELDS  

SciTech Connect

A Newtonian model of non-conductive, charged, perfect fluid tori orbiting in combined spherical gravitational and dipolar magnetic fields is presented and stationary, axisymmetric toroidal structures are analyzed. Matter in such tori exhibits a purely circulatory motion and the resulting convection carries charges into permanent rotation around the symmetry axis. As a main result, we demonstrate the possible existence of off-equatorial charged tori and equatorial tori with cusps that also enable outflows of matter from the torus in the Newtonian regime. These phenomena qualitatively represent a new consequence of the interplay between gravity and electromagnetism. From an astrophysical point of view, our investigation can provide insight into processes that determine the vertical structure of dusty tori surrounding accretion disks.

Slany, P.; Kovar, J.; Stuchlik, Z. [Institute of Physics, Faculty of Philosophy and Science, Silesian University in Opava Bezrucovo nam. 13, CZ-746 01 Opava (Czech Republic)] [Institute of Physics, Faculty of Philosophy and Science, Silesian University in Opava Bezrucovo nam. 13, CZ-746 01 Opava (Czech Republic); Karas, V., E-mail: petr.slany@fpf.slu.cz [Astronomical Institute, Academy of Sciences, Bocni II, Prague CZ-141 31 (Czech Republic)

2013-03-01T23:59:59.000Z

4

Apparatus and method for generating a magnetic field by rotation of a charge holding object  

DOE Patents (OSTI)

A device and a method for the production of a magnetic field using a Charge Holding Object that is mechanically rotated. In a preferred embodiment, a Charge Holding Object surrounding a sample rotates and subjects the sample to one or more magnetic fields. The one or more magnetic fields are used by NMR Electronics connected to an NMR Conductor positioned within the Charge Holding Object to perform NMR analysis of the sample.

Gerald, II, Rex E. (Brookfield, IL); Vukovic, Lela (Westchester, IL); Rathke, Jerome W. (Homer Glenn, IL)

2009-10-13T23:59:59.000Z

5

Two charges on plane in a magnetic field: II. Moving neutral quantum system across a magnetic field  

E-Print Network (OSTI)

The moving neutral system of two Coulomb charges on a plane subject to a constant magnetic field $B$ perpendicular to the plane is considered. It is shown that the composite system of finite total mass is bound for any center-of-mass momentum $P$ and magnetic field strength; the energy of the ground state is calculated accurately using a variational approach. Their accuracy is cross-checked in a Lagrange-mesh method for $B=1$ a.u. and in a perturbation theory at small $B$ and $P$. The constructed trial function has the property of being a uniform approximation of the exact eigenfunction. For a Hydrogen atom and a Positronium a double perturbation theory in $B$ and $P$ is developed and the first corrections are found algebraically. A phenomenon of a sharp change of energy behavior for a certain center-of-mass momentum and a fixed magnetic field is indicated.

M. A. Escobar-Ruiz; A. V. Turbiner

2014-07-10T23:59:59.000Z

6

Zero field line in the magnetic spectra of negatively charged nitrogen-vacancy centers in diamond  

E-Print Network (OSTI)

The dependence of the luminescence of diamonds with negatively charged nitrogen-vacancy centers (NV-) vs. applied magnetic field (magnetic spectrum) was studied. A narrow line in zero magnetic field was discovered. The properties of this line are considerably different from those of other narrow magnetic spectrum lines. Its magnitude is weakly dependent of the orientation of the single-crystal sample to the external magnetic field. This line is also observed in a powdered sample. The shape of the line changes greatly when excitation light polarization is varied. The magnitude of the line has a non-linear relation to excitation light intensity. For low intensities this dependence is close to a square law. To explain the mechanism giving rise to this line in the magnetic spectrum, we suggest a model based on the dipole-dipole interaction between different NV- centers.

S. V. Anishchik; V. G. Vins; A. P. Yelisseyev; N. N. Lukzen; N. L. Lavrik; V. A. Bagryansky

2014-07-02T23:59:59.000Z

7

Electric charge in the field of a magnetic event in three-dimensional spacetime  

E-Print Network (OSTI)

We analyze the motion of an electric charge in the field of a magnetically charged event in three-dimensional spacetime. We start by exhibiting a first integral of the equations of motion in terms of the three conserved components of the spacetime angular momentum, and then proceed numerically. After crossing the light cone of the event, an electric charge initially at rest starts rotating and slowing down. There are two lengths appearing in the problem: (i) the characteristic length $\\frac{q g}{2 \\pi m}$, where $q$ and $m$ are the electric charge and mass of the particle, and $g$ is the magnetic charge of the event; and (ii) the spacetime impact parameter $r_0$. For $r_0 \\gg \\frac{q g}{2 \\pi m}$, after a time of order $r_0$, the particle makes sharply a quarter of a turn and comes to rest at the same spatial position at which the event happened in the past. This jump is the main signature of the presence of the magnetic event as felt by an electric charge. A derivation of the expression for the angular momentum that uses Noether's theorem in the magnetic representation is given in the Appendix.

Claudio Bunster; Cristian Martinez

2012-02-09T23:59:59.000Z

8

Polarization Effects In The Charged Lepton Pair Production By A Neutrino (Antineutrino) In A Magnetic Field  

SciTech Connect

The probability of the process of the charged lepton pair production by a neutrino (an antineutrino) with allowance for the longitudinal and transverse polarizations of the charged leptons in a magnetic field is presented. The dependence of the probability of the process on the spin variables of the charged leptons and on the azimuthal and polar angles of the initial and final neutrinos (antineutrinos) are investigated. It is shown that the probability of the process is sensitive to the spin variables of the charged leptons and to the direction of the neutrino (antineutrino) momentum. It is determined that the neutrino (antineutrino) energy and momentum loss through the production of a charged lepton pair happens asymmetrically.

Huseynov, Vali A. [Department of General and Theoretical Physics, Nakhchivan State University, AZ 7000, Nakhchivan (Azerbaijan); Laboratory of Physical Research, Nakhchivan Division of Azerbaijan National Academy of Sciences, AZ 7000, Nakhchivan (Azerbaijan); Ahmad, Ali S. [Department of General and Theoretical Physics, Nakhchivan State University, AZ 7000, Nakhchivan (Azerbaijan)

2007-06-13T23:59:59.000Z

9

Two-loop corrections to the potential of a pointlike charge in a superstrong magnetic field  

SciTech Connect

The potential of the pointlike charge in a superstrong homogeneous magnetic field B Much-Greater-Than m{sub e}{sup 2}/e{sup 3} Almost-Equal-To 6 Multiplication-Sign 10{sup 15} G is considered. It is well known that Coulomb potential is significantly modified by taking into account vacuum polarization (calculated in one loop approximation). We consider electron selfenergy and correction to the vertex function at one loop, and show that these diagrams are not enhanced by magnetic field like eB.We calculate two-loop corrections to the vacuum polarization and find that these contributions are small.

Godunov, S. I., E-mail: sgodunov@itep.ru [All-Russia Research Institute of Automatics (RRIA) (Russian Federation)

2013-07-15T23:59:59.000Z

10

The Meissner effect in the ground state of free charged Bosons in a constant magnetic field  

E-Print Network (OSTI)

The model of free charged Bosons in an external constant magnetic field inside a cylinder, one of the few locally gauge covariant systems amenable to analytic treatment, is rigorously investigated in the semiclassical approximation. The model was first studied by Schafroth and is suitable for the description of quasi-bound electron pairs localized in physical space, so-called Schafroth pairs, which occur in certain compounds, but he used perturbation theory on the magnetic field, which is not applicable to the homogeneous fields for which the thermodynamical results may be derived. A simple nonperturbative spectral argument shows that, for sufficiently low values of the magnetic field, the ground state expectation value of the current $$ is of the London form $ = -\\lambda(\\vec{x}) \\vec{A}(\\vec{x})$, with $\\lambda$ a positive function of $\\vec{x}$, $\\vec{A}$ denoting the magnetic vector potential. As a consequence, the magnetic induction inside the sample is given by a non-uniform field, monotonically decreasing from the surface. Under a plausible assumption on the ground state wave function, the Meissner effect is derived, and the results fit the thermodynamics calculated by Schafroth as a finite size correction. We also briefly review the link with relativistic quantum field theory, in particular with London-Schwinger screening.

Walter F. Wreszinski

2014-08-31T23:59:59.000Z

11

Local CP-violation and electric charge separation by magnetic fields from lattice QCD  

E-Print Network (OSTI)

We study local CP-violation on the lattice by measuring the local correlation between the topological charge density and the electric dipole moment of quarks, induced by a constant external magnetic field. This correlator is found to increase linearly with the external field, with the coefficient of proportionality depending only weakly on temperature. Results are obtained on lattices with various spacings, and are extrapolated to the continuum limit after the renormalization of the observables is carried out. This renormalization utilizes the gradient flow for the quark and gluon fields. Our findings suggest that the strength of local CP-violation in QCD with physical quark masses is about an order of magnitude smaller than a model prediction based on nearly massless quarks in domains of constant gluon backgrounds with topological charge. We also show numerical evidence that the observed local CP-violation correlates with spatially extended electric dipole structures in the QCD vacuum.

G. S. Bali; F. Bruckmann; G. Endrodi; Z. Fodor; S. D. Katz; A. Schafer

2014-01-16T23:59:59.000Z

12

Anomalous diffusion of field lines and charged particles in Arnold-Beltrami-Childress force-free magnetic fields  

SciTech Connect

The cosmic magnetic fields in regions of low plasma pressure and large currents, such as in interstellar space and gaseous nebulae, are force-free in the sense that the Lorentz force vanishes. The three-dimensional Arnold-Beltrami-Childress (ABC) field is an example of a force-free, helical magnetic field. In fluid dynamics, ABC flows are steady state solutions of the Euler equation. The ABC magnetic field lines exhibit a complex and varied structure that is a mix of regular and chaotic trajectories in phase space. The characteristic features of field line trajectories are illustrated through the phase space distribution of finite-distance and asymptotic-distance Lyapunov exponents. In regions of chaotic trajectories, an ensemble-averaged variance of the distance between field lines reveals anomalous diffusion—in fact, superdiffusion—of the field lines. The motion of charged particles in the force-free ABC magnetic fields is different from the flow of passive scalars in ABC flows. The particles do not necessarily follow the field lines and display a variety of dynamical behavior depending on their energy, and their initial pitch-angle. There is an overlap, in space, of the regions in which the field lines and the particle orbits are chaotic. The time evolution of an ensemble of particles, in such regions, can be divided into three categories. For short times, the motion of the particles is essentially ballistic; the ensemble-averaged, mean square displacement is approximately proportional to t{sup 2}, where t is the time of evolution. The intermediate time region is defined by a decay of the velocity autocorrelation function—this being a measure of the time after which the collective dynamics is independent of the initial conditions. For longer times, the particles undergo superdiffusion—the mean square displacement is proportional to t{sup ?}, where ??>?1, and is weakly dependent on the energy of the particles. These super-diffusive characteristics, both of magnetic field lines and of particles moving in these fields, strongly suggest that theories of transport in three-dimensional chaotic magnetic fields need a shift from the usual paradigm of quasilinear diffusion.

Ram, Abhay K. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Dasgupta, Brahmananda [Center for Space Plasma and Aeronomic Research, University of Alabama in Huntsville, Huntsville, Alabama 35805 (United States); Krishnamurthy, V. [Center for Ocean-Land-Atmosphere Studies, George Mason University, Fairfax, Virginia 22030 (United States); Mitra, Dhrubaditya [Nordita, KTH Royal Institute of Technology and Stockholm University, 10691 Stockholm (Sweden)

2014-07-15T23:59:59.000Z

13

Possibility of using active secondary charge-exchange particle diagnostics for measuring the magnetic field direction in the plasma of a magnetic fusion reactor  

Science Journals Connector (OSTI)

An active particle diagnostic method based on the secondary charge exchange of hydrogen atoms of a probing (diagnostic) beam is proposed for local measurements of the magnetic field direction in the plasma of a t...

A. A. Medvedev; V. S. Strelkov

2006-05-01T23:59:59.000Z

14

Charge-Transfer Induced Magnetic Field Effects of Nano-Carbon Heterojunctions  

E-Print Network (OSTI)

Room temperature magnetic field effects have not been definitively observed in either single-walled carbon nanotubes (SWCNTs) or C60 under a small magnetic field due to their weak hyperfine interaction and slight difference of g-factor between...

Qin, Wei; Gong, Maogang; Shastry, Tejas; Hersam, Mark C.; Ren, Sheqiang

2014-08-22T23:59:59.000Z

15

Sources and Magnetic Charge  

Science Journals Connector (OSTI)

A beginning is made on a phenomenological reconstruction of the theory of magnetic charge. The concept is introduced by reference to a new kind of photon source. It is shown that photon exchange between different source types is relativistically invariant. The space-time generalization of this coupling involves an arbitrary vector. The only way to remove a corresponding arbitrariness of physical predictions is to recognize the localization of charge and impose a charge quantization condition. The consideration of particles that carry both kinds of charge loosens the charge restrictions. The great strength of magnetic attraction indicated by g24?=4(137) suggests that ordinary matter is a magnetically neutral composite of magnetically charged particles that carry fractional electric charge. There is a brief discussion of such a magnetic model of strongly interacting particles, which makes contact with empirical classification schemes. Additional remarks on notation, and on the general nature of the source description, are appended.

Julian Schwinger

1968-09-25T23:59:59.000Z

16

Improvement of charged particles transport across a transverse magnetic filter field by electrostatic trapping of magnetized electrons  

SciTech Connect

A study on the transport of charged particles across a magnetic filter field has been carried out in a double plasma device (DPD) and presented in this manuscript. The DPD is virtually divided into two parts viz. source and target regions by a transverse magnetic field (TMF) which is constructed by inserting strontium ferrite magnets into two stainless steel rectangular tubes. Plasma electrons are magnetized but ions are unmagnetized inside the TMF region. Negative voltages are applied to the TMF tubes in order to reduce the loss of electrons towards them. Plasma is produced in the source region by filament discharge method and allowed to flow towards the target region through this negatively biased TMF. It is observed that in the target region, plasma density can be increased and electron temperature decreased with the help of negatively biased TMF. This observation is beneficial for negative ion source development. Plasma diffusion across the negatively biased TMF follows Bohm or anomalous diffusion process when negative bias voltage is very less. At higher negative bias, diffusion coefficient starts deviating from the Bohm diffusion value, associated with enhanced plasma flow in the target region.

Das, B. K., E-mail: bdyt.ds@rediffmail.com; Hazarika, P.; Chakraborty, M. [Centre of Plasma Physics-Institute for Plasma Research, Tepesia-782402, Kamrup, Assam (India); Bandyopadhyay, M., E-mail: mainak@iter-india.org [ITER-India, Institute for Plasma Research, Gandhinagar-382025, Gujarat (India)

2014-07-15T23:59:59.000Z

17

Magnetic charge and the charge quantization condition  

Science Journals Connector (OSTI)

Two viewpoints concerning magnetic charge are distinguished: that of Dirac, which is unsymmetrical, and the symmetrical one, which embodies invariance under charge rotation. It is pointed out that the latter is not in conflict with the empirical asymmetry between electric and magnetic charge. The discussion is based on an action principle that uses field strengths and the vector potential A as independent variables; a second vector potential B is defined nonlocally in terms of the field strengths. This nonlocality is described by an arbitrary vector function f?(y), subject only to the restriction ??f?(y)=?(y) and the additional requirement of oddness, in the symmetrical formulation. The charge quantization conditions for a pair of idealized charges, a and b, are inferred by examining the dependence of the action W on the choice of the arbitrary mathematical function f, and requiring the uniqueness of exp [iW]. For the unsymmetrical viewpoint the half-integer condition of Dirac is obtained, eagb4?=12n, while the symmetrical formulation requires the integer condition (eagb-ebga)4?=n. The Dirac injunction, "a string must never pass through a charged particle," is criticized as unnecessarily restrictive, owing to its origin in a classical action context. As simplified by a restriction to small momentum transfers, permitting the neglect of form-factor and vacuum-polarization effects, the dynamics of a realistic system of two spin- ½ dyons is shown to involve the same interaction structure used in the idealized discussion.

Julian Schwinger

1975-11-15T23:59:59.000Z

18

Induced Fractional Zero-Point Canonical Angular Momentum on Charged Particles of Aharonov - Bohm Vector Potential and "Spectator" Magnetic Field  

E-Print Network (OSTI)

The induced fractional zero-point canonical angular momentum on charged particles by the Aharonov - Bohm (AB) vector potential is realized via modified combined traps. It explores new features for this type of quantum effects: In a limit of vanishing mechanical kinetic energy the AB vector potential alone cannot induce a fractional zero-point canonical angular momentum on charged particles at the quantum mechanical level in the AB magnetic field-free region; But for the case of the AB vector potential with another one of a "spectator" magnetic field the AB vector potential induces a fractional zero-point canonical angular momentum in the same limit. The "spectator" one does not contribute to such a fractional zero-point quantity, but plays essential role in guaranteeing non-trivial dynamics survived in this limit at the quantum mechanical level. These results are significance in investigations of the AB effects and related fields for both theories and experiments.

Jian-Zu Zhang

2007-09-06T23:59:59.000Z

19

Magnetic guidance of charged particles  

E-Print Network (OSTI)

Many experiments and devices in physics use static magnetic fields to guide charged particles from a source onto a detector, and we ask the innocent question: What is the distribution of particle intensity over the detector surface? One should think that the solution to this seemingly simple problem is well known. We show that, even for uniform guide fields, this is not the case and present analytical point spread functions (PSF) for magnetic transport that deviate strongly from previous results. The "magnetic" PSF shows unexpected singularities, which were recently also observed experimentally, and which make detector response very sensitive to minute changes of position, field amplitude, or particle energy. In the field of low-energy particle physics, these singularities may become a source of error in modern high precision experiments, or may be used for instrument tests, for instance in neutrino mass retardation spectrometers.

Dubbers, Dirk

2015-01-01T23:59:59.000Z

20

Synchro-curvature radiation of charged particles in the strong curved magnetic fields  

E-Print Network (OSTI)

It is generally believed that the radiation of relativistic particles in a curved magnetic field proceeds in either the synchrotron or the curvature radiation modes. In this paper we show that in strong curved magnetic fields a significant fraction of the energy of relativistic electrons can be radiated away in the intermediate, the so-called synchro-curvature regime. Because of the persistent change of the trajectory curvature, the radiation varies with the frequency of particle gyration. While this effect can be ignored in the synchrotron and curvature regimes, the variability plays a key role in the formation of the synchro-curvature radiation. Using the Hamiltonian formalism, we find that the particle trajectory has the form of a helix wound around the drift trajectory. This allows us to calculate analytically the intensity and energy distribution of prompt radiation in the general case of magnetic bremsstrahlung in the curved magnetic field. We show that the transition to the limit of the synchrotron and...

Kelner, S R; Aharonian, F A

2015-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "magnetic field charged" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Electric- and Magnetic-Charge Renormalization. I  

Science Journals Connector (OSTI)

An important question in the field theory of electric and magnetic charge is the relative renormalization of the two kinds of charges. A general view of renormalization, as a scale change introduced in proceeding from the field to the particle level of description, indicates the universality of charge renormalization. This is confirmed by an explicit calculation of the long-range interaction of static charges.

Julian Schwinger

1966-11-25T23:59:59.000Z

22

Magnetic Field Safety Training  

NLE Websites -- All DOE Office Websites (Extended Search)

Safety Training Magnetic Field Safety Strong Magnetic Fields exist around energized magnets. High magnetic fields alone are a recognized hazard only for personnel with certain...

23

Deconfined fractional electric charges in graphene at high magnetic fields Chang-Yu Hou,1 Claudio Chamon,1 and Christopher Mudry2  

E-Print Network (OSTI)

Deconfined fractional electric charges in graphene at high magnetic fields Chang-Yu Hou,1 Claudio The resistance at the charge neutral Dirac point was shown by Checkelsky et al. Phys. Rev. B 79, 115434 2009.43. f I. INTRODUCTION The elementary excitations in the fractional quantum Hall FQH effect carry

24

Magnetic Field Safety Magnetic Field Safety  

E-Print Network (OSTI)

Magnetic Field Safety Training #12;Magnetic Field Safety Strong Magnetic Fields exist around energized magnets. High magnetic fields alone are a recognized hazard only for personnel with certain medical conditions such as pacemakers, magnetic implants, or embedded shrapnel. In addition, high magnetic

McQuade, D. Tyler

25

Intrinsic Magnetic Fields  

Science Journals Connector (OSTI)

Emission theory of electromagnetic fields.—(1) Intrinsic magnetic field. The intrinsic magnetic field of a point charge is defined as that portion of the field which cannot be annihilated by the Lorentz transformation. It is shown that the intrinsic field can be represented by lines of force carried by the same moving elements as carry the electric field, and a potential is given for it. (2) Frequency of emission of moving elements. A relation between the frequency of emission of moving elements and the number of lines of force to a tube is deduced on the assumption that the latter number is the same for the electric and magnetic fields and that each moving element marks the intersection of an electric and magnetic line of force.

Leigh Page

1923-08-01T23:59:59.000Z

26

Motion of a Charged Particle in a Static Magnetic Field with Axial Symmetry  

Science Journals Connector (OSTI)

......Aspects of Controlled Fusion Research (1959...Problems of Controlled Thermonuclear Reactions (1958...magnetic machines for fusion or acceleration devices...Aspects of Controlled Fusion Research (Gatlinburg...Problem$ of Controlled Thermonuclear Re- actions, (Acad......

Haruo Obayashi

1961-02-01T23:59:59.000Z

27

Magnetic moment versus tensor charge  

E-Print Network (OSTI)

We express the baryon magnetic moments in terms of the baryon tensor charges, considering the quarks as relativistic interacting objects. Once tensor charges get measured accurately, the formula for the baryon magnetic moment will serve to extract precise information on the quark anomalous magnetic moment, the quark effective mass and the ratio of the quark constituent mass to the quark effective mass. The analogous formula for the baryon electric dipole moment is of no great use as it gets eventually sizable contributions from various CP- violating sources not necessary associated to the quark electric dipole moment.

M. Mekhfi

2005-05-10T23:59:59.000Z

28

Ch 16 Electric Charge &Ch 16. Electric Charge & Electric Field  

E-Print Network (OSTI)

Ch 16 Electric Charge &Ch 16. Electric Charge & Electric Field Liu UCD Phy1B 2012 #12;I Basic ConceptsI. Basic Concepts Static electricity: charges at rest Electric charge Like charges repel Unlike charges attract Liu UCD Phy1B 2012 #12;Electric ChargeElectric Charge Electron charge: -eElectron charge

Yoo, S. J. Ben

29

Electric Charge and Electric Field Electrostatics: Charge at rest  

E-Print Network (OSTI)

Chapter 16 Electric Charge and Electric Field #12;Electrostatics: Charge at rest Electric Charges of conservation of Electric Charge: The net amount of electric charge produced in any process is zero. Model, neutral). #12;· All protons and electrons have same magnitude of electric charge but their masses

Yu, Jaehoon

30

Magnetic Fields Analogous to electric field, a magnet  

E-Print Network (OSTI)

characteristic of elementary particles such as an electron #12;Magnetic Fields Magnetic field lines Direction;Magnetic Fields Magnetic field lines enter one end (south) of magnet and exit the other end (north) Opposite magnetic poles attract like magnetic poles repel #12;Like the electric field lines

Bertulani, Carlos A. - Department of Physics and Astronomy, Texas A&M University

31

Magnetic Field Viewing Cards  

Science Journals Connector (OSTI)

For some years now laminated cards containing a green magnetically sensitive film have been available from science education suppliers. When held near a magnet these cards appear dark green in regions where the field is perpendicular to the card and light green where the field is parallel to the card. The cards can be used to explore the magnetic field near a variety of magnets as well as near wire loops. In this paper we describe how to make these cards and how we have used them in our physics classrooms and labs.

Stephen Kanim; John R. Thompson

2005-01-01T23:59:59.000Z

32

Transport of Field Lines and Particles in a Stochastic Magnetic Field  

Science Journals Connector (OSTI)

In this chapter the transport of field lines and charged particles in a stochastic magnetic field will be investigated. To study this problem...

Sadrilla Abdullaev

2014-01-01T23:59:59.000Z

33

Very-low-frequency and low-frequency electric and magnetic fields associated with electric shuttle bus wireless charging  

Science Journals Connector (OSTI)

......the charging process brings the batteries up to 90 per cent of the full...the test track to reduce the battery's SOC to between 60 and 70...2012) EVS26 International Battery, Hybrid and Fuel Cell Electric Vehicle Symposium......

R.A. Tell; Robert Kavet; J.R. Bailey; John Halliwell

2014-01-01T23:59:59.000Z

34

Permanent magnet edge-field quadrupole  

DOE Patents (OSTI)

Planar permanent magnet edge-field quadrupoles for use in particle accelerating machines and in insertion devices designed to generate spontaneous or coherent radiation from moving charged particles are disclosed. The invention comprises four magnetized rectangular pieces of permanent magnet material with substantially similar dimensions arranged into two planar arrays situated to generate a field with a substantially dominant quadrupole component in regions close to the device axis. 10 figs.

Tatchyn, R.O.

1997-01-21T23:59:59.000Z

35

Coordinate noncommutativity in strong non-uniform magnetic fields  

E-Print Network (OSTI)

Noncommuting spatial coordinates are studied in the context of a charged particle moving in a strong non-uniform magnetic field. We derive a relation involving the commutators of the coordinates, which generalizes the one realized in a strong constant magnetic field. As an application, we discuss the noncommutativity in the magnetic field present in a magnetic mirror.

J. Frenkel; S. H. Pereira

2004-09-23T23:59:59.000Z

36

Seeing the Invisible: Educating the Public on Planetary Magnetic Fields and How they Affect Atmospheres  

E-Print Network (OSTI)

Seeing the Invisible: Educating the Public on Planetary Magnetic Fields and How they Affect to visualize ­ invisible · But planetary magnetic field and charged particle environments (magnetospheres

Fillingim, Matthew

37

SP - 19 Magnetic Field Safety  

NLE Websites -- All DOE Office Websites (Extended Search)

19 Page 1 Revision 02 August 6, 2007 NATIONAL HIGH MAGNETIC FIELD LABORATORY NHMFL FLORIDA STATE UNIVERSITY SAFETY PROCEDURE SP-19 MAGNETIC FIELD SAFETY ...

38

Synchrotron Radiation in Directions Close to Magnetic-Field Lines  

Science Journals Connector (OSTI)

It is characteristic of the radiation from a particle of mass m bearing a charge e moving with ultrarelativistic velocity ? c in a magnetic field of induction B

K. C. Westfold

1974-01-01T23:59:59.000Z

39

Mapping Magnetic Near-Field Distributions of Plasmonic Nanoantennas  

Science Journals Connector (OSTI)

However, standard far-field optical microscopy methods have insufficient resolution and provide no information about the electromagnetic near-fields. ... The top right panel of Figure 3a illustrates how the charges and magnetic near-field (green circles) at the probe aperture line up with the charge distribution and magnetic near-field of the SPR mode. ... and magnetic field lines and Poynting vector distributions are reconstructed in a vol. ...

Denitza Denkova; Niels Verellen; Alejandro V. Silhanek; Ventsislav K. Valev; Pol Van Dorpe; Victor V. Moshchalkov

2013-03-06T23:59:59.000Z

40

Magnetic Field Effects on Copper Electrolysis  

Science Journals Connector (OSTI)

Four different magnets were used to supply a static magnetic field to the cell during the various electrochemical experiments. ... A Halbach cylinder with a fixed static field of 0.5 T in a 54 mm bore or a 48 mm bore Multimag38 permanent magnet system capable of delivering variable fields in the range 0?1.0 T in any direction transverse to the bore was used for the lower field experiments. ... The Lorentz force, F?L, arises from the motion of charge across lines of magnetic flux, whereas the electrokinetic force, F?E, results from the stress on the charge carriers in the diffuse double layer under the influence of a nonelectrostatic field, E??, parallel to the electrode surface. ...

G. Hinds; F. E. Spada; J. M. D. Coey; T. R. Ní Mhíocháin; M. E. G. Lyons

2001-09-12T23:59:59.000Z

Note: This page contains sample records for the topic "magnetic field charged" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

National High Magnetic Field Laboratory Audio Dictionary: Magnetic...  

NLE Websites -- All DOE Office Websites (Extended Search)

Links Magnets from Mini to Mighty Meet the Magnets How to Make an Electromagnet (audio slideshow) Compasses in Magnetic Fields (interactive tutorial) Magnetic Field Around a...

42

Low field magnetic resonance imaging  

DOE Patents (OSTI)

A method and system of magnetic resonance imaging does not need a large homogenous field to truncate a gradient field. Spatial information is encoded into the spin magnetization by allowing the magnetization to evolve in a non-truncated gradient field and inducing a set of 180 degree rotations prior to signal acquisition.

Pines, Alexander (Berkeley, CA); Sakellariou, Dimitrios (Billancourt, FR); Meriles, Carlos A. (Fort Lee, NJ); Trabesinger, Andreas H. (London, GB)

2010-07-13T23:59:59.000Z

43

THE GALACTIC MAGNETIC FIELD  

SciTech Connect

With this Letter, we complete our model of the Galactic magnetic field (GMF), by using the WMAP7 22 GHz total synchrotron intensity map and our earlier results to obtain a 13-parameter model of the Galactic random field, and to determine the strength of the striated random field. In combination with our 22-parameter description of the regular GMF, we obtain a very good fit to more than 40,000 extragalactic Faraday rotation measures and the WMAP7 22 GHz polarized and total intensity synchrotron emission maps. The data call for a striated component to the random field whose orientation is aligned with the regular field, having zero mean and rms strength Almost-Equal-To 20% larger than the regular field. A noteworthy feature of the new model is that the regular field has a significant out-of-plane component, which had not been considered earlier. The new GMF model gives a much better description of the totality of data than previous models in the literature.

Jansson, Ronnie; Farrar, Glennys R. [Center for Cosmology and Particle Physics, Department of Physics, New York University, New York, NY 10003 (United States)

2012-12-10T23:59:59.000Z

44

National High Magnetic Field Laboratory: Superconductors  

NLE Websites -- All DOE Office Websites (Extended Search)

opposes the magnetic field generating the current. In a perfect diamagnet, the magnetic field lines produced exactly mirror those of the changing magnetic field that induce them,...

45

Ambipolar Diffusion in a Magnetic Field  

Science Journals Connector (OSTI)

Diffusion of ions in a plasma across a magnetic field is shown to be not ambipolar in character in most arc experiments. Owing to the highly anisotropic conductivity of the medium, the ions diffuse across the field at their own intrinsic rate. Space-charge neutralization is maintained by slight adjustments of the currents in the direction of the magnetic field lines. The discrepancy between theory and experiment noted by Bohm is thus resolved and no additional mechanisms, such as plasma oscillations, need be postulated.

Albert Simon

1955-04-15T23:59:59.000Z

46

Particle energization through time-periodic helical magnetic fields  

E-Print Network (OSTI)

We solve for the motion of charged particles in a helical time-periodic ABC (Arnold-Beltrami-Childress) magnetic field. The magnetic field lines of a stationary ABC field with coefficients A=B=C=1 are chaotic, and we show ...

Mitra, Dhrubaditya

47

Magnetic-field-dosimetry system  

DOE Patents (OSTI)

A device is provided for measuring the magnetic field dose and peak field exposure. The device includes three Hall-effect sensors all perpendicular to each other, sensing the three dimensional magnetic field and associated electronics for data storage, calculating, retrieving and display.

Lemon, D.K.; Skorpik, J.R.; Eick, J.L.

1981-01-21T23:59:59.000Z

48

A magnetic spectrometer measurement of the charge ratio of energetic cosmic ray muons  

E-Print Network (OSTI)

" of 35 Bev. Th, . " periment has been carried out with a magnetic momentum spectrometer-telescope consisting of two separate solid- izon magnets in conjun tinn iwith detectors of penetrating ionizing particles. The incident particles recorded were... directions of the particles as they entered the top magnet and the exit directions from the lower magnet. The magnitudes and directions of the deflections in the known magnetic field have then been used to determine the moments and charges...

Bateman, Benjamin Jefferson

2012-06-07T23:59:59.000Z

49

Transverse charge and magnetization densities in the nucleon's chiral periphery  

SciTech Connect

In the light-front description of nucleon structure the electromagnetic form factors are expressed in terms of frame-independent transverse densities of charge and magnetization. Recent work has studied the transverse densities at peripheral distances b = O(M{pi}{sup -1}), where they are governed by universal chiral dynamics and can be computed in a model-independent manner. Of particular interest is the comparison of the peripheral charge and magnetization densities. We summarize (a) their interpretation as spin-independent and -dependent current matrix elements; (b) the leading-order chiral effective field theory results; (c) their mechanical interpretation in the light-front formulation; (d) the large-N_c limit of QCD and the role of {Delta} intermediate states; (e) the connection with generalized parton distributions and peripheral high-energy scattering processes.

Granados, Carlos G. [JLAB Newport News, VA (United States); Weiss, Christian [JLAB Newport News, VA (United States)

2014-01-01T23:59:59.000Z

50

Two-dimensional oscillator in a magnetic field  

SciTech Connect

The energy and eigenstate spectrum of a charged particle in the electric field of a 2D anisotropic oscillator and in a uniform magnetic field is considered. The exact analytic solution to the problem is obtained for an arbitrary magnetic field strength. The characteristic features of variation of the energy spectrum depending on the magnetic field strength are analyzed. The results of this study are of interest for the quantum-mechanical theory of magnetism and can be used to simulate the magnetic properties of atoms and molecules.

Rebane, T. K., E-mail: trebane@mail.ri [St. Petersburg University, Fock Research Institute of Physics (Russian Federation)

2012-02-15T23:59:59.000Z

51

Chaotic motion of charged particles in toroidal magnetic configurations  

E-Print Network (OSTI)

We study the motion of a charged particle in a tokamak magnetic field and discuss its chaotic nature. Contrary to most of recent studies, we do not make any assumption on any constant of the motion and solve numerically the cyclotron gyration using Hamiltonian formalism. We take advantage of a symplectic integrator allowing us to make long-time simulations. First considering an idealized magnetic configuration, we add a non generic perturbation corresponding to a magnetic ripple, breaking one of the invariant of the motion. Chaotic motion is then observed and opens questions about the link between chaos of magnetic field lines and chaos of particle trajectories. Second, we return to a axi-symmetric configuration and tune the safety factor (magnetic configuration) in order to recover chaotic motion. In this last setting with two constants of the motion, the presence of chaos implies that no third global constant exists, we highlight this fact by looking at variations of the first order of the magnetic moment in this chaotic setting. We are facing a mixed phase space with both regular and chaotic regions and point out the difficulties in performing a global reduction such as gyrokinetics.

Benjamin Cambon; Xavier Leoncini; Michel Vittot; Rémi Dumont; Xavier Garbet

2014-02-11T23:59:59.000Z

52

CHAPTER 3. STRUCTURE OF MAGNETIC FIELDS 1 Structure of Magnetic  

E-Print Network (OSTI)

CHAPTER 3. STRUCTURE OF MAGNETIC FIELDS 1 Chapter 3 Structure of Magnetic Fields Many of the most interesting plasmas are permeated by or imbedded in magnetic fields.1 As shown in Fig. 3.1, the magnetic field properties of magnetic fields in plasmas can be discussed without specifying a model for the plasma

Callen, James D.

53

Magnetic field in a finite toroidal domain  

SciTech Connect

The magnetic field structure in a domain surrounded by a closed toroidal magnetic surface is analyzed. It is shown that ergodization of magnetic field lines is possible even in a regular field configuration (with nonvanishing toroidal component). A unified approach is used to describe magnetic fields with nested toroidal (possibly asymmetric) flux surfaces, magnetic islands, and ergodic field lines.

Ilgisonis, V. I.; Skovoroda, A. A., E-mail: skovorod@nfi.kiae.r [Russian Research Centre Kurchatov Institute (Russian Federation)

2010-05-15T23:59:59.000Z

54

National High Magnetic Field Laboratory - Visualizing Field Lines...  

NLE Websites -- All DOE Office Websites (Extended Search)

Now You See It: Visualizing Field Lines Try This At Home The magnetic field is the area around the magnet where the magnetic forces act. Actually, magnets are made up of many, many...

55

The electric charge and magnetic moment of neutral fundamental particles  

E-Print Network (OSTI)

The article focuses on the issue of the two definitions of charge, mainly the gauge charge and the effective charge of fundamental particles. Most textbooks on classical electromagnetism and quantum field theory only works with the gauge charges while the concept of the induced charge remains unattended. In this article it has been shown that for intrinsically charged particles both of the charges remain the same but there can be situations where an electrically neutral particle picks up some electrical charge from its plasma surrounding. The physical origin and the scope of application of the induced charge concept has been briefly discussed in the article.

Kaushik Bhattacharya

2009-05-27T23:59:59.000Z

56

Determination of Electric-Field, Magnetic-Field, and Electric...  

NLE Websites -- All DOE Office Websites (Extended Search)

Electric-Field, Magnetic-Field, and Electric-Current Distributions of Infrared Optical Antennas: A Near-Field Determination of Electric-Field, Magnetic-Field, and Electric-Current...

57

The Sun's global magnetic field  

Science Journals Connector (OSTI)

...the plasma in the Sun's atmosphere...representation of the Sun's large-scale...high density and temperature contrast between...the density and temperature distributions found in the global...magnetic fields on the Sun and other stars...

2012-01-01T23:59:59.000Z

58

Neutron in Strong Magnetic Fields  

E-Print Network (OSTI)

Relativistic world-line Hamiltonian for strongly interacting 3q systems in magnetic field is derived from the path integral for the corresponding Green's function. The neutral baryon Hamiltonian in magnetic field obeys the pseudomomentum conservation and allows a factorization of the c.m. and internal motion. The resulting expression for the baryon mass in magnetic field is written explicitly with the account of hyperfine, OPE and OGE (color Coulomb) interaction. The neutron mass is fast decreasing with magnetic field, losing 1/2 of its value at eB~0.25 GeV^2 and is nearly zero at eB~0.5 GeV^2. Possible physical consequences of the calculated mass trajectory of the neutron, M_n(B), are presented and discussed.

M. A. Andreichikov; B. O. Kerbikov; V. D. Orlovsky; Yu. A. Simonov

2013-12-08T23:59:59.000Z

59

Optical sensor of magnetic fields  

DOE Patents (OSTI)

An optical magnetic field strength sensor for measuring the field strength of a magnetic field comprising a dilute magnetic semi-conductor probe having first and second ends, longitudinally positioned in the magnetic field for providing Faraday polarization rotation of light passing therethrough relative to the strength of the magnetic field. Light provided by a remote light source is propagated through an optical fiber coupler and a single optical fiber strand between the probe and the light source for providing a light path therebetween. A polarizer and an apparatus for rotating the polarization of the light is provided in the light path and a reflector is carried by the second end of the probe for reflecting the light back through the probe and thence through the polarizer to the optical coupler. A photo detector apparatus is operably connected to the optical coupler for detecting and measuring the intensity of the reflected light and comparing same to the light source intensity whereby the magnetic field strength may be calculated.

Butler, M.A.; Martin, S.J.

1986-03-25T23:59:59.000Z

60

High Field Magnetic Resonance Facility  

NLE Websites -- All DOE Office Websites (Extended Search)

HFMRF Overview HFMRF Overview Section 2-3-1 High Field Magnetic Resonance Facility The High Field Magnetic Resonance Facility (HFMRF) focuses a significant portion of its research on developing a fundamental, molecular-level understanding of biochemical and biological systems and their response to environmental effects. A secondary focus is materials science, including catalysis and chemical mechanisms and processes. Staff and science consultants within this facility offer expertise in the areas of structural biology, solid-state materials characterization, and magnetic resonance imaging (MRI) techniques. Research activities in the HFMRF include: * structure determination of large molecular assemblies such as protein-DNA (normal and damaged DNA) and protein-RNA complexes

Note: This page contains sample records for the topic "magnetic field charged" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

National High Magnetic Field Laboratory: An Introduction to Magnets...  

NLE Websites -- All DOE Office Websites (Extended Search)

resistive magnet is here at the Magnet Lab: It can generate a sustained magnetic field of 35 tesla. (Were not counting here our world-record hybrid magnet or the stronger,...

62

National High Magnetic Field Laboratory: An Introduction to Magnets...  

NLE Websites -- All DOE Office Websites (Extended Search)

is a magnet); opposite poles attract, like poles repel. In all magnets, the magnetic field lines run from south to north, and these fields are what produce forces on other...

63

Electric Field-Induced Skyrmion Crystals via Charged Monopoles in Insulating Helimagets  

E-Print Network (OSTI)

Electrons propagating in a magnetically ordered medium experience an additional gauge field associated with the Berry phase of their spin following the local magnetic texture. In contrast to the usual electromagnetic field, this gauge field admits monopole excitations, corresponding to hedgehog defects of the magnetic order. In an insulator, these hedgehogs carry a well-defined electric charge allowing for them to be controlled by electric fields. One particularly robust mechanism that contributes to the charge is the orbital magnetoelectric effect, captured by a $\\theta$ angle, which leads to a charge of $e\\theta/2\\pi$ on hedgehogs. This is a direct consequence of the Witten effect for magnetic monopoles in a $\\theta$ medium. A physical consequence is that external electric fields can induce skyrmion crystal phases in insulating helimagnets.

Watanabe, Haruki

2014-01-01T23:59:59.000Z

64

Electric Field-Induced Skyrmion Crystals via Charged Monopoles in Insulating Helimagets  

E-Print Network (OSTI)

Electrons propagating in a magnetically ordered medium experience an additional gauge field associated with the Berry phase of their spin following the local magnetic texture. In contrast to the usual electromagnetic field, this gauge field admits monopole excitations, corresponding to hedgehog defects of the magnetic order. In an insulator, these hedgehogs carry a well-defined electric charge allowing for them to be controlled by electric fields. One particularly robust mechanism that contributes to the charge is the orbital magnetoelectric effect, captured by a $\\theta$ angle, which leads to a charge of $e\\theta/2\\pi$ on hedgehogs. This is a direct consequence of the Witten effect for magnetic monopoles in a $\\theta$ medium. A physical consequence is that external electric fields can induce skyrmion crystal phases in insulating helimagnets.

Haruki Watanabe; Ashvin Vishwanath

2014-10-08T23:59:59.000Z

65

Field theoretic description of charge regulation interaction  

E-Print Network (OSTI)

In order to find the exact form of the electrostatic interaction between two proteins with dissociable charge groups in aqueous solution, we have studied a model system composed of two macroscopic surfaces with charge dissociation sites immersed in a counterion-only ionic solution. Field-theoretic representation of the grand canonical partition function is derived and evaluated within the mean-field approximation, giving the Poisson-Boltzmann theory with the Ninham-Parsegian boundary condition. Gaussian fluctuations around the mean-field are then analyzed in the lowest order correction that we calculate analytically and exactly, using the path integral representation for the partition function of a harmonic oscillator with time-dependent frequency. The first order (one loop) free energy correction gives the interaction free energy that reduces to the zero-frequency van der Waals form in the appropriate limit but in general gives rise to a mono-polar fluctuation term due to charge fluctuation at the dissociation sites. Our formulation opens up the possibility to investigate the Kirkwood-Shumaker interaction in more general contexts where their original derivation fails.

Natasa Adzic; Rudolf Podgornik

2014-05-15T23:59:59.000Z

66

Magnetic field lines for a flux tube  

Science Journals Connector (OSTI)

Equations for the magnetic field components in a two dimensional cylindrically symmetric ... in a simple case, solved. The resulting magnetic configuration possesses a strong magnetic field in a thin tube below a...

C. D. C. Steele; Rekha Jain

1993-05-01T23:59:59.000Z

67

National High Magnetic Field Laboratory Slideshow: Seeing Magnetic...  

NLE Websites -- All DOE Office Websites (Extended Search)

more about magnets You can start here with a straightforward rundown. Compasses in Magnetic Fields Experiment with the compass in this tutorial to see how it responds to...

68

Magnetic Charge Lattices, Moduli Spaces and Fusion Rules  

E-Print Network (OSTI)

We analyze the set of magnetic charges carried by smooth BPS monopoles in Yang-Mills-Higgs theory with arbitrary gauge group G spontaneously broken to a subgroup H. The charges are restricted by a generalized Dirac quantization condition and by an inequality due to Murray. Geometrically, the set of allowed charges is a solid cone in the coroot lattice of G, which we call the Murray cone. We argue that magnetic charge sectors correspond to points in the Murray cone divided by the Weyl group of H; hence magnetic charge sectors are labelled by dominant integral weights of the dual group H*. We define generators of the Murray cone modulo Weyl group, and interpret the monopoles in the associated magnetic charge sectors as basic; monopoles in sectors with decomposable charges are interpreted as composite configurations. This interpretation is supported by the dimensionality of the moduli spaces associated to the magnetic charges and by classical fusion properties for smooth monopoles in particular cases. Throughout the paper we compare our findings with corresponding results for singular monopoles recently obtained by Kapustin and Witten.

L. Kampmeijer; J. K. Slingerland; B. J. Schroers; F. A. Bais

2008-03-24T23:59:59.000Z

69

High Field Magnet R&D |Superconducting Magnet Division  

NLE Websites -- All DOE Office Websites (Extended Search)

High Field Magnet R&D High Field Magnet R&D The Superconducting Magnet Division is developing advanced magnet designs and magnet-related technologies for high field accelerator magnets. We are currently working on magnets for three inter-related programs: High Field Magnets for Muon Collider Papers, Presentations Common Coil Magnets Papers, Presentations Interaction Region Magnets Papers, Presentations High Temperature Superconductor (HTS) Magnets Papers, Presentations This is part of a multi-lab superconducting magnet development program for new accelerator facilities that would be part of the U.S. High Energy Physics program. These programs (@BNL, @FNAL, @LBNL) are quite complimentary to each other, so that magnet designs and technologies developed at one laboratory can be easily transferred to another. The BNL

70

Thermoelectric effects in organic conductors in a strong magnetic field  

SciTech Connect

The linear response of the electron system of a layered conductor to the temperature gradient in this system in a strong magnetic field is investigated theoretically. Thermoelectric emf is studied as a function of the magnitude and orientation of a strong external magnetic field; the experimental investigation of this function, combined with the study of the electric and thermal resistance, allows one to completely determine the structure of the energy spectrum of charge carriers.

Kirichenko, O. V.; Peschanskii, V. G. [National Academy of Sciences of Ukraine, Verkin Institute for Low Temperature Physics and Engineering (Ukraine)], E-mail: vpeschansky@ilt.kharkov.ua; Hasan, R. A. [Bir-Zeit University (Autonomy of Palestine) (Country Unknown)

2007-07-15T23:59:59.000Z

71

Free energies in magnetic fields  

Science Journals Connector (OSTI)

The partition function is calculated exactly at low temperatures and dimensionality one in the presence of a magnetic field for ferromagnetic systems of n-component unit vectors with nearest-neighbor interactions. For n=2 the free energy is proportional to the lowest eigenvalue of Mathieu's equation. Asymptotic solutions for n=3 are also given.

Jorge V. José

1976-09-01T23:59:59.000Z

72

Magnetic charge crystals imaged in artificial spin ice  

NLE Websites -- All DOE Office Websites (Extended Search)

Magnetic charge crystals imaged in artificial spin ice Magnetic charge crystals imaged in artificial spin ice Magnetic charge crystals imaged in artificial spin ice Potential data storage and computational advances could follow August 27, 2013 Potential data storage and computational advances could follow A 3-D depiction of the honeycomb artificial spin ice topography after the annealing and cooling protocols. The light and dark colors represent the north and south magnetic poles of the islands. Image by Ian Gilbert, U. of I. Department of Physics and Frederick Seitz Materials Research Laboratory Contact Nancy Ambrosiano Communications Office (505) 667-0471 Email Siv Schwink U. Illinois (217) 300-2201 Email "The emergence of magnetic monopoles in spin ice systems is a particular case of what physicists call fractionalization, or deconfinement of

73

Separation of magnetic field lines  

SciTech Connect

The field lines of magnetic fields that depend on three spatial coordinates are shown to have a fundamentally different behavior from those that depend on two coordinates. Unlike two-coordinate cases, a flux tube in a magnetic field that depends on all three spatial coordinates that has a circular cross section at one location along the tube characteristically has a highly distorted cross section at other locations. In an ideal evolution of a magnetic field, the current densities typically increase. Crudely stated, if the current densities increase by a factor {sigma}, the ratio of the long to the short distance across a cross section of a flux tube characteristically increases by e{sup 2{sigma}}, and the ratio of the longer distance to the initial radius increases as e{sup {sigma}}. Electron inertia prevents a plasma from isolating two magnetic field structures on a distance scale shorter than c/{omega}{sub pe}, which is about 10 cm in the solar corona, and reconnection must be triggered if {sigma} becomes sufficiently large. The radius of the sun, R{sub Circled-Dot-Operator }=7 Multiplication-Sign 10{sup 10}cm is about e{sup 23} times larger, so when {sigma} Greater-Than-Or-Equivalent-To 23, two lines separated by c/{omega}{sub pe} at one location can be separated by the full scale of any magnetic structures in the corona at another. The conditions for achieving a large exponentiation, {sigma}, are derived, and the importance of exponentiation is discussed.

Boozer, Allen H. [Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027 (United States)

2012-11-15T23:59:59.000Z

74

The strength of galactic magnetic fields  

Science Journals Connector (OSTI)

... UK THE magnitudes of galactic magnetic fields are usually estimated from measurements of the radio synchroton emission arising from acceleration of cosmic-ray electrons in the magnetic field. To interpret ...

X. Chi; A. W. Wolfendale

1993-04-15T23:59:59.000Z

75

Magnetic fields in the solar photosphere  

Science Journals Connector (OSTI)

...magnetoconvection in the quiet Sun. Filled contours show the temperature variations in a horizontal...Sanchez Almeida2003Quiet-Sun magnetic fields at high...Almeida, and F Kneer2006The distribution of quiet Sun magnetic field strengths...

2008-01-01T23:59:59.000Z

76

The motion of magnetic field lines  

Science Journals Connector (OSTI)

The definition and applications of the motion of magnetic lines of force are reviewed and illustrated. First ... aid to describing the evolution of a known magnetic field. It is next shown that a known velocity field

David P. Stern

1966-11-01T23:59:59.000Z

77

Graphene transparency in weak magnetic fields  

E-Print Network (OSTI)

We carry out an explicit calculation of the vacuum polarization tensor for an effective low-energy model of monolayer graphene in the presence of a weak magnetic field of intensity $B$ perpendicularly aligned to the membrane. By expanding the quasiparticle propagator in the Schwinger proper time representation up to order $(eB)^2$, where $e$ is the unit charge, we find an explicitly transverse tensor, consistent with gauge invariance. Furthermore, assuming that graphene is radiated with monochromatic light of frequency $\\omega$ along the external field direction, from the modified Maxwell's equations we derive the intensity of transmitted light and the angle of polarization rotation in terms of the longitudinal ($\\sigma_{xx}$) and transverse ($\\sigma_{xy}$) conductivities. Corrections to these quantities, both calculated and measured, are of order $(eB)^2/\\omega^4$. Our findings generalize and complement previously known results reported in literature regarding the light absorption problem in graphene from th...

Valenzuela, David; Loewe, Marcelo; Raya, Alfredo

2014-01-01T23:59:59.000Z

78

National High Magnetic Field Laboratory - Drawing Field Lines...  

NLE Websites -- All DOE Office Websites (Extended Search)

A Portrait of Magnetism: Drawing Field Lines Try This At Home Magnets have two poles; the field lines spread out from the north pole and circle back around to the south pole. In...

79

Rotating copper plasmoid in external magnetic field  

SciTech Connect

Effect of nonuniform magnetic field on the expanding copper plasmoid in helium and argon gases using optical emission spectroscopy and fast imaging is presented. We report a peculiar oscillatory rotation of plasmoid in magnetic field and argon ambient. The temporal variation and appearance of the dip in the electron temperature show a direct evidence of the threading and expulsion of the magnetic field lines from the plasmoid. Rayleigh Taylor instability produced at the interface separating magnetic field and plasma is discussed.

Pandey, Pramod K.; Thareja, Raj K. [Department of Physics, Indian Institute of Technology Kanpur, Uttar Pradesh 208 016 (India)

2013-02-15T23:59:59.000Z

80

CORONAL MAGNETIC FIELD MEASUREMENTS THROUGH GYRORESONANCE EMISSION  

E-Print Network (OSTI)

Chapter 5 CORONAL MAGNETIC FIELD MEASUREMENTS THROUGH GYRORESONANCE EMISSION Stephen M. White This article reviews the use of gyroresonance emission at radio wavelengths to measure coronal magnetic fields. Keywords: Sun, solar corona, solar magnetic fields, solar radio emission Introduction Since the realization

White, Stephen

Note: This page contains sample records for the topic "magnetic field charged" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Magnetic monopole and the nature of the static magnetic field  

E-Print Network (OSTI)

We investigate the factuality of the hypothetical magnetic monopole and the nature of the static magnetic field. It is shown from many aspects that the concept of the massive magnetic monopoles clearly is physically untrue. We argue that the static magnetic field of a bar magnet, in fact, is the static electric field of the periodically quasi-one-dimensional electric-dipole superlattice, which can be well established in some transition metals with the localized d-electron. This research may shed light on the perfect unification of magnetic and electrical phenomena.

Xiuqing Huang

2008-12-10T23:59:59.000Z

82

Graphene transparency in weak magnetic fields  

E-Print Network (OSTI)

We carry out an explicit calculation of the vacuum polarization tensor for an effective low-energy model of monolayer graphene in the presence of a weak magnetic field of intensity $B$ perpendicularly aligned to the membrane. By expanding the quasiparticle propagator in the Schwinger proper time representation up to order $(eB)^2$, where $e$ is the unit charge, we find an explicitly transverse tensor, consistent with gauge invariance. Furthermore, assuming that graphene is radiated with monochromatic light of frequency $\\omega$ along the external field direction, from the modified Maxwell's equations we derive the intensity of transmitted light and the angle of polarization rotation in terms of the longitudinal ($\\sigma_{xx}$) and transverse ($\\sigma_{xy}$) conductivities. Corrections to these quantities, both calculated and measured, are of order $(eB)^2/\\omega^4$. Our findings generalize and complement previously known results reported in literature regarding the light absorption problem in graphene from the experimental and theoretical points of view, with and without external magnetic fields.

David Valenzuela; Saúl Hernández-Ortiz; Marcelo Loewe; Alfredo Raya

2014-10-20T23:59:59.000Z

83

Charge quantisation without magnetic monopoles: a topological approach to electromagnetism  

E-Print Network (OSTI)

The present work provides a theoretical explanation for the quantisation of electric charges, an open problem since Millikan's oil drop experiment in 1909. This explanation is based solely on Maxwell's theory, it recasts Electromagnetic theory under the language of complex line bundles; therefore, neither magnetic monopoles nor quantum mechanics are invoked. Essentially, the existence of magnetic monopoles was the only theoretical explanation for charge quantisation (e.g. Dirac's monopole), and there is no experimental data supporting their existence ---on the contrary, they have nerver been observed.

Romero Solha

2014-06-24T23:59:59.000Z

84

Standstill Electric Charge Generates Magnetostatic Field Under Born-Infeld Electrodynamics  

E-Print Network (OSTI)

The Abelian Born-Infeld classical non-linear electrodynamic has been used to investigate the electric and magnetostatic fields generated by a point-like electrical charge at rest in an inertial frame. The results show a rich internal structure for the charge. Analytical solutions have also been found. Such findings have been interpreted in terms of vacuum polarization and magnetic-like charges produced by the very high strengths of the electric field considered. Apparently non-linearity is to be accounted for the emergence of an anomalous magnetostatic field suggesting a possible connection to that created by a magnetic dipole composed of two mognetic charges with opposite signals. Consistently in situations where the Born-Infeld field strength parameter is free to become infinite, Maxwell`s regime takes over, the magnetic sector vanishes and the electric field assumes a Coulomb behavior with no trace of a magnetic component. The connection to other monopole solutions, like Dirac`s, t' Hooft`s or Poliakov`s types, are also discussed. Finally some speculative remarks are presented in an attempt to explain such fields.

S. O. Vellozo; Jose A. Helayel-Neto; A. W. Smith; L. P. G. De Assis

2008-02-21T23:59:59.000Z

85

Electromagnetic Dipole Radiation Fields, Shear-Free Congruences and Complex Center of Charge World Lines  

E-Print Network (OSTI)

We show that for asymptotically vanishing Maxwell fields in Minkowski space with non-vanishing total charge, one can find a unique geometric structure, a null direction field, at null infinity. From this structure a unique complex analytic world-line in complex Minkowski space that can be found and then identified as the complex center of charge. By ''sitting'' - in an imaginary sense, on this world-line both the (intrinsic) electric and magnetic dipole moments vanish. The (intrinsic) magnetic dipole moment is (in some sense) obtained from the `distance' the complex the world line is from the real space (times the charge). This point of view unifies the asymptotic treatment of the dipole moments For electromagnetic fields with vanishing magnetic dipole moments the world line is real and defines the real (ordinary center of charge). We illustrate these ideas with the Lienard-Wiechert Maxwell field. In the conclusion we discuss its generalization to general relativity where the complex center of charge world-line has its analogue in a complex center of mass allowing a definition of the spin and orbital angular momentum - the analogues of the magnetic and electric dipole moments.

Carlos N. Kozameh; Ezra T. Newman

2005-04-20T23:59:59.000Z

86

Permanent Magnet Ecr Plasma Source With Magnetic Field Optimization  

DOE Patents (OSTI)

In a plasma-producing device, an optimized magnet field for electron cyclotron resonance plasma generation is provided by a shaped pole piece. The shaped pole piece adjusts spacing between the magnet and the resonance zone, creates a convex or concave resonance zone, and decreases stray fields between the resonance zone and the workpiece. For a cylindrical permanent magnet, the pole piece includes a disk adjacent the magnet together with an annular cylindrical sidewall structure axially aligned with the magnet and extending from the base around the permanent magnet. The pole piece directs magnetic field lines into the resonance zone, moving the resonance zone further from the face of the magnet. Additional permanent magnets or magnet arrays may be utilized to control field contours on a local scale. Rather than a permeable material, the sidewall structure may be composed of an annular cylindrical magnetic material having a polarity opposite that of the permanent magnet, creating convex regions in the resonance zone. An annular disk-shaped recurve section at the end of the sidewall structure forms magnetic mirrors keeping the plasma off the pole piece. A recurve section composed of magnetic material having a radial polarity forms convex regions and/or magnetic mirrors within the resonance zone.

Doughty, Frank C. (Plano, TX); Spencer, John E. (Plano, TX)

2000-12-19T23:59:59.000Z

87

Magnetic line trapping and effective transport in stochastic magnetic fields  

Science Journals Connector (OSTI)

The transport of collisional particles in stochastic magnetic fields is studied using the decorrelation trajectory method. The nonlinear effect of magnetic line trapping is considered together with particle collisions. The running diffusion coefficient is determined for arbitrary values of the statistical parameters of the stochastic magnetic field and of the collisional velocity. The effect of the magnetic line trapping is determined. New anomalous diffusion regimes are found.

M. Vlad; F. Spineanu; J. H. Misguich; R. Balescu

2003-02-07T23:59:59.000Z

88

Charge screening and magnetic anisotropy in metallic rare-earth systems  

Science Journals Connector (OSTI)

The calculation of magnetic anisotropy constants is performed beyond the point-charge model for a continuous charge-density distribution of screening conduction electrons. An important role of the nonuniform electron density, in particular, of the Friedel oscillations, in the formation of crystal field is demonstrated. Such effects can modify strongly the effective ion (impurity) charge and even change its sign. This enables one to justify the anion model, which is often used for discussing experimental data on hydrogen-containing systems. Possible applications to the pure rare-earth metals and RCo5 (R=rare earth) compounds are discussed. The deformation of magnetic structure near the interstitial positive muon owing to the strong local anisotropy, and the corresponding contribution to the dipole field at the muon are considered.

V. Yu. Irkhin and Yu. P. Irkhin

1998-02-01T23:59:59.000Z

89

Presented by the National High Magnetic Field Laboratory  

E-Print Network (OSTI)

Magnets These lines show the magnetic field created by the bar magnet. Look, this magnetic field looks like an apple! Field Lines #12;Scientists at the Magnet Lab use a special kind of magnet calledPresented by the National High Magnetic Field Laboratory Learning About Name #12;A magnet

Weston, Ken

90

Superconducting strip in an oblique magnetic field  

Science Journals Connector (OSTI)

As an example for a seemingly simple but actually intricate problem, we study the Bean critical state in a superconducting strip of finite thickness d and width 2w?d placed in an oblique magnetic field. The analytical solution is obtained to leading order in the small parameter d?w. The critical state depends on how the applied magnetic field is switched on, e.g., at a constant tilt angle, or first the perpendicular and then the parallel field component. For these two basic scenarios we obtain the distributions of current density and magnetic field in the critical states. In particular, we find the shapes of the flux-free core and of the lines separating regions with opposite direction of the critical currents, the detailed magnetic field lines (along the vortex lines), and both components of the magnetic moment. The component of the magnetic moment parallel to the strip plane is a nonmonotonic function of the applied magnetic field.

G. P. Mikitik; E. H. Brandt; M. Indenbom

2004-07-30T23:59:59.000Z

91

Nematic order of model goethite nanorods in a magnetic field  

E-Print Network (OSTI)

We explore the nematic order of model goethite nanorods in an external magnetic field within Onsager-Parsons density functional theory. The goethite rods are represented by monodisperse, charged spherocylinders with a permanent magnetic moment along the rod main axis, forcing the particles to align parallel to the magnetic field at low field strength. The intrinsic diamagnetic susceptibility anisometry of the rods is negative which leads to a preferred perpendicular orientation at higher field strength. It is shown that these counteracting effects may give rise to intricate phase behavior, including a pronounced stability of biaxial nematic order and the presence of reentrant phase transitions and demixing phenomena. The effect of the applied field on the nematic-to-smectic transition will also be addressed.

H. H. Wensink; G. J. Vroege

2005-01-18T23:59:59.000Z

92

Unique topological characterization of braided magnetic fields  

SciTech Connect

We introduce a topological flux function to quantify the topology of magnetic braids: non-zero, line-tied magnetic fields whose field lines all connect between two boundaries. This scalar function is an ideal invariant defined on a cross-section of the magnetic field, and measures the average poloidal magnetic flux around any given field line, or the average pairwise crossing number between a given field line and all others. Moreover, its integral over the cross-section yields the relative magnetic helicity. Using the fact that the flux function is also an action in the Hamiltonian formulation of the field line equations, we prove that it uniquely characterizes the field line mapping and hence the magnetic topology.

Yeates, A. R. [Department of Mathematical Sciences, Durham University, Durham DH1 3LE (United Kingdom); Hornig, G. [Division of Mathematics, University of Dundee, Dundee DD1 4HN (United Kingdom)

2013-01-15T23:59:59.000Z

93

Bipolar pulse field for magnetic refrigeration  

DOE Patents (OSTI)

A magnetic refrigeration apparatus includes first and second steady state magnets, each having a field of substantially equal strength and opposite polarity, first and second bodies made of magnetocaloric material disposed respectively in the influence of the fields of the first and second steady state magnets, and a pulsed magnet, concentric with the first and second steady state magnets, and having a field which cycles between the fields of the first and second steady state magnets, thereby cyclically magnetizing and demagnetizing and thus heating and cooling the first and second bodies. Heat exchange apparatus of suitable design can be used to expose a working fluid to the first and second bodies of magnetocaloric material. A controller is provided to synchronize the flow of working fluid with the changing states of magnetization of the first and second bodies. 2 figs.

Lubell, M.S.

1994-10-25T23:59:59.000Z

94

National High Magnetic Field Laboratory: Team Tesla - How we...  

NLE Websites -- All DOE Office Websites (Extended Search)

resistive magnets (also called electromagnets or Bitter magnets), ranging in magnetic field from 20 tesla to 45 tesla, each in its own little cell. These magnets get so...

95

Magnetic field perturbations in the systems where only poloidal magnetic field is present*  

E-Print Network (OSTI)

. Introduction of a weak regular toroidal magnetic field reduces radial excursions of the field lines. Possible #12;6 The equations for the perturbed magnetic field line are: dr dJ = dBr +dB1r B0 +dBJ ; dz dJ = d1 Magnetic field perturbations in the systems where only poloidal magnetic field is present* D

96

National High Magnetic Field Laboratory: Museum of Electricity...  

NLE Websites -- All DOE Office Websites (Extended Search)

chemistry. Related Electricity & Magnetism Pages Interactive Java Tutorials: Magnetic Field Lines Around a Wire Interactive Java Tutorials: Magnetic Field Lines Around a Wire, II...

97

National High Magnetic Field Laboratory: Museum of Electricity...  

NLE Websites -- All DOE Office Websites (Extended Search)

strength of a magnetic field. He also made significant contributions to our understanding of the Earth's magnetic field. Related Electricity & Magnetism Pages Timeline: 1830 - 18...

98

National High Magnetic Field Laboratory: Museum of Electricity...  

NLE Websites -- All DOE Office Websites (Extended Search)

of the Earths magnetic field to the research community. Related Electricity & Magnetism Pages Interactive Java Tutorials: Compasses in Magnetic Fields Interactive Java...

99

Neutron in a Strong Magnetic Field: Finite Volume Effects  

E-Print Network (OSTI)

We investigate the neutron's response to magnetic fields on a torus with the aid of chiral perturbation theory, and expose effects from non-vanishing holonomies. The determination of such effects necessitates non-perturbative treatment of the magnetic field; and, to this end, a strong-field power counting is employed. Using a novel coordinate-space method, we find the neutron propagates in a coordinate-dependent effective potential that we obtain by integrating out charged pions winding around the torus. Knowledge of these finite volume effects will aid in the extraction of neutron properties from lattice QCD computations in external magnetic fields. In particular, we obtain finite volume corrections to the neutron magnetic moment and magnetic polarizability. These quantities have not been computed correctly in the literature. In addition to effects from non-vanishing holonomies, finite volume corrections depend on the magnetic flux quantum through an Aharonov-Bohm effect. We make a number of observations that demonstrate the importance of non-perturbative effects from strong magnetic fields currently employed in lattice QCD calculations. These observations concern neutron physics in both finite and infinite volume.

Brian C. Tiburzi

2014-03-04T23:59:59.000Z

100

Primordial magnetic fields in false vacuum inflation  

Science Journals Connector (OSTI)

We show that, during false vacuum inflation, a primordial magnetic field can be created sufficiently strong to seed the galactic dynamo and generate the observed galactic magnetic fields. Considering the inflaton-dominated regime, our field is produced by the Higgs-field gradients, resulting from a grand unified phase transition. The evolution of the field is followed from its creation through to the epoch of structure formation, subject to the relevant constraints. We find that it is possible to create a magnetic field of sufficient magnitude, provided the phase transition occurs during the final five e-foldings of the inflationary period.

Anne-Christine Davis and Konstantinos Dimopoulos

1997-06-15T23:59:59.000Z

Note: This page contains sample records for the topic "magnetic field charged" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

National High Magnetic Field Laboratory - Publications  

NLE Websites -- All DOE Office Websites (Extended Search)

Lett. Physica B Physica C Physica E Polymer Polymer J. Proc. Physical Phenomena at High Magnetic Fields - IV Protein Science PROTEINS: Structure, Function and Genetics Rapid...

102

Magnetic Fields in Clusters of Galaxies  

E-Print Network (OSTI)

A brief overview about our knowledge on galaxy cluster magnetic fields is provided. Emphasize is given to the mutual dependence of our knowledge on relativistic particles in galaxy clusters and the magnetic field strength. Furthermore, we describe efforts to measure magnetic field strengths, characteristic length-scales, and power-spectra with reliable accuracy. An interpretation of these results in terms of non-helical dynamo theory is given. If this interpretation turns out to be correct, the understanding of cluster magnetic fields is directly connected to our understanding of intra-cluster turbulence.

Torsten A. Ensslin; Corina Vogt; Christoph Pfrommer

2005-01-17T23:59:59.000Z

103

Constructing the Coronal Magnetic Field By Correlating Parameterized Magnetic Field Lines With Observed Coronal Plasma Structures  

Science Journals Connector (OSTI)

A method is presented for constructing the coronal magnetic field from photospheric magnetograms and observed coronal loops. A set of magnetic field lines generated from magnetogram data is parameterized and ... ...

G. Allen Gary; David Alexander

1999-05-01T23:59:59.000Z

104

The National High Magnetic Field Laboratory: Condensed Matter Science in Continuous Magnetic Fields  

Science Journals Connector (OSTI)

The National High Magnetic Field Laboratory (NHMFL) operates three facilities ... Tallahassee, Florida, the ultra-low-temperature high-magnetic-field facilities are located at the University ... scientific achiev...

M. D. Bird; J. E. Crow; P. Schlottmann

2003-10-01T23:59:59.000Z

105

Cryogenic Magnet Could Open New Fields  

Science Journals Connector (OSTI)

Now that its cryogenic superconducting magnet is commercially available (C&EN, Jan. 15, page 43), Westinghouse Electric expects the magnet to open up new areas of high-field magnet research with possible use in magnetohydrodynamics, thermonuclear fusion, and cryogenic devices. ...

1962-01-22T23:59:59.000Z

106

Magnetic field decay in model SSC dipoles  

SciTech Connect

We have observed that some of our model SSC dipoles have long time constant decays of the magnetic field harmonics with amplitudes large enough to result in significant beam loss, if they are not corrected. The magnets were run at constant current at the SSC injection field level of 0.3 tesla for one to three hours and changes in the magnetic field were observed. One explanation for the observed field decay is time dependent superconductor magnetization. Another explanation involves flux creep or flux flow. Data are presented on how the decay changes with previous flux history. Similar magnets with different Nb-Ti filament spacings and matrix materials have different long time field decay. A theoretical model using proximity coupling and flux creep for the observed field decay is discussed. 10 refs., 5 figs., 2 tabs.

Gilbert, W.S.; Althaus, R.F.; Barale, P.J.; Benjegerdes, R.W.; Green, M.A.; Green, M.I.; Scanlan, R.M.

1988-08-01T23:59:59.000Z

107

Ground-state magnetic phase diagram of bow-tie graphene nanoflakes in external magnetic field  

SciTech Connect

The magnetic phase diagram of a ground state is studied theoretically for graphene nanoflakes of bow-tie shape and various sizes in external in-plane magnetic field. The tight-binding Hamiltonian supplemented with Hubbard term is used to model the electronic structure of the systems in question. The existence of the antiferromagnetic phase with magnetic moments localized at the sides of the bow-tie is found for low field and a field-induced spin-flip transition to ferromagnetic state is predicted to occur in charge-undoped structures. For small nanoflake doped with a single charge carrier, the low-field phase is ferrimagnetic and a metamagnetic transition to ferromagnetic ordering can be forced by the field. The critical field is found to decrease with increasing size of the nanoflake. The influence of diagonal and off-diagonal disorder on the mentioned magnetic properties is studied. The effect of off-diagonal disorder is found to be more important than that of diagonal disorder, leading to significantly widened distribution of critical fields for disordered population of nanoflakes.

Sza?owski, Karol, E-mail: kszalowski@uni.lodz.pl, E-mail: kszalowski@wp.pl [Department of Solid State Physics, Faculty of Physics and Applied Informatics, University of ?ód?, ul. Pomorska 149/153, 90-236 ?ód? (Poland)

2013-12-28T23:59:59.000Z

108

Graphene Nanoribbon in Sharply Localized Magnetic Fields  

E-Print Network (OSTI)

We study the effect of a sharply localized magnetic field on the electron transport in a strip (ribbon) of graphene sheet, which allows to give results for the transmission and reflection probability through magnetic barriers. The magnetic field is taken as a single and double delta type localized functions, which are treated later as the zero width limit of gaussian fields. For both field configurations, we evaluate analytically and numerically their transmission and reflection coefficients. The possibility of spacial confinement due to the inhomogeneous field configuration is also investigated.

Abdulaziz D. Alhaidari; Hocine Bahlouli; Abderrahim El Mouhafid; Ahmed Jellal

2011-03-21T23:59:59.000Z

109

High concentration ferronematics in low magnetic fields  

E-Print Network (OSTI)

We investigated experimentally the magneto-optical and dielectric properties of magnetic-nanoparticle-doped nematic liquid crystals (ferronematics). Our studies focus on the effect of the very small orienting bias magnetic field $B_{bias}$, and that of the nematic director pretilt at the boundary surfaces in our systems sensitive to low magnetic fields. Based on the results we assert that $B_{bias}$ is not necessarily required for a detectable response to low magnetic fields, and that the initial pretilt, as well as the aggregation of the nanoparticles play an important (though not yet explored enough) role.

T. Tóth-Katona; P. Salamon; N. Éber; N. Tomašovi?ová; Z. Mitróová; P. Kop?anský

2014-09-05T23:59:59.000Z

110

Magnetic field outflows from active galactic nuclei  

Science Journals Connector (OSTI)

We examine several models of injecting magnetic fields into clusters of galaxies from active galactic nuclei, which are the powerful outflows associated with supermassive black holes in the centers of clusters. Shown are magnetic field lines after six ... Keywords: scientific visualization

David Pugmire; Paul Sutter; Paul Ricker; Hsiang-Yi (Karen) Yang; George Foreman

2011-11-01T23:59:59.000Z

111

Local magnetic fields in disordered metals  

Science Journals Connector (OSTI)

We show that in a disordered metal the local magnetic fields generated by the magnetic-field-induced orbital-electron currents will fluctuate strongly in magnitude and direction. We argue that this phenomenon should be reflected by a noticeable inhomogeneous broadening of NMR lines and analyze its dependence on system geometry and temperature.

R. A. Serota and A. Yu. Zyuzin

1993-06-01T23:59:59.000Z

112

Hydrogen atom moving across a magnetic field  

Science Journals Connector (OSTI)

A hydrogen atom moving across a magnetic field is considered in a wide region of magnitudes of magnetic field and atom momentum. We solve the Schrödinger equation of the system numerically using an imaginary time method and find wave functions of the lowest states of atom. We calculate the energy and the mean electron-nucleus separation as a function of atom momentum and magnetic field. All the results obtained could be summarized as a phase diagram on the “atom-momentum – magnetic-field” plane. There are transformations of wave-function structure at critical values of atom momentum and magnetic field that result in a specific behavior of dependencies of energy and mean interparticle separation on the atom momentum P. We discuss a transition from the Zeeman regime to the high magnetic field regime. A qualitative analysis of the complicated behavior of wave functions vs P based on the effective potential examination is given. We analyze a sharp transition at the critical momentum from a Coulomb-type state polarized due to atom motion to a strongly decentered (Landau-type) state at low magnetic fields. A crossover occurring at intermediate magnetic fields is also studied.

Yu. E. Lozovik and S. Yu. Volkov

2004-08-23T23:59:59.000Z

113

Energy of magnetic moment of superconducting current in magnetic field  

E-Print Network (OSTI)

The energy of magnetic moment of the persistent current circulating in superconducting loop in an externally produced magnetic field is not taken into account in the theory of quantization effects because of identification of the Hamiltonian with the energy. This identification misleads if, in accordance with the conservation law, the energy of a state is the energy expended for its creation. The energy of magnetic moment is deduced from a creation history of the current state in magnetic field both in the classical and quantum case. But taking this energy into account demolishes the agreement between theory and experiment. Impartial consideration of this problem discovers the contradiction both in theory and experiment.

V. L. Gurtovoi; A. V. Nikulov

2014-12-22T23:59:59.000Z

114

Magnetic fields in Neutron Stars  

E-Print Network (OSTI)

Isolated neutron stars show a diversity in timing and spectral properties, which has historically led to a classification in different sub-classes. The magnetic field plays a key role in many aspects of the neutron star phenomenology: it regulates the braking torque responsible for their timing properties and, for magnetars, it provides the energy budget for the outburst activity and high quiescent luminosities (usually well above the rotational energy budget). We aim at unifying this observational variety by linking the results of the state-of-the-art 2D magneto-thermal simulations with observational data. The comparison between theory and observations allows to place two strong constraints on the physical properties of the inner crust. First, strong electrical currents must circulate in the crust, rather than in the star core. Second, the innermost part of the crust must be highly resistive, which is in principle in agreement with the presence of a novel phase of matter so-called nuclear pasta phase.

Viganò, Daniele; Miralles, Juan A; Rea, Nanda

2015-01-01T23:59:59.000Z

115

The Magnetic Field in the Solar Atmosphere  

E-Print Network (OSTI)

This publication provides an overview of magnetic fields in the solar atmosphere with the focus lying on the corona. The solar magnetic field couples the solar interior with the visible surface of the Sun and with its atmosphere. It is also responsible for all solar activity in its numerous manifestations. Thus, dynamic phenomena such as coronal mass ejections and flares are magnetically driven. In addition, the field also plays a crucial role in heating the solar chromosphere and corona as well as in accelerating the solar wind. Our main emphasis is the magnetic field in the upper solar atmosphere so that photospheric and chromospheric magnetic structures are mainly discussed where relevant for higher solar layers. Also, the discussion of the solar atmosphere and activity is limited to those topics of direct relevance to the magnetic field. After giving a brief overview about the solar magnetic field in general and its global structure, we discuss in more detail the magnetic field in active regions, the quie...

Wiegelmann, Thomas; Solanki, Sami K

2014-01-01T23:59:59.000Z

116

Warm inflation in presence of magnetic fields  

SciTech Connect

We present preliminary results on the possible effects that primordial magnetic fields can have for a warm inflation scenario, based on global supersymmetry, with a new-inflation-type potential. This work is motivated by two considerations: first, magnetic fields seem to be present in the universe on all scales which rises de possibility that they could also permeate the early universe; second, the recent emergence of inflationary models where the inflaton is not assumed to be isolated but instead it is taken as an interacting field, even during the inflationary expansion. The effects of magnetic fields are included resorting to Schwinger's proper time method.

Piccinelli, Gabriella [Centro Tecnológico, FES Aragón, Universidad Nacional Autónoma de México, Avenida Rancho Seco S/N, Bosques de Aragón, Nezahualcóyotl, Estado de México 57130 (Mexico)] [Centro Tecnológico, FES Aragón, Universidad Nacional Autónoma de México, Avenida Rancho Seco S/N, Bosques de Aragón, Nezahualcóyotl, Estado de México 57130 (Mexico); Sánchez, Ángel [Department of Physics, University of Texas at El Paso, El Paso, Texas 79968 (United States)] [Department of Physics, University of Texas at El Paso, El Paso, Texas 79968 (United States); Ayala, Alejandro; Mizher, Ana Julia [Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Apartado Postal 70-543, México Distrito Federal 04510 (Mexico)] [Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Apartado Postal 70-543, México Distrito Federal 04510 (Mexico)

2013-07-23T23:59:59.000Z

117

Sub-100 nm Confinement of Magnetic Nanoparticles Using Localized Magnetic Field Gradients  

E-Print Network (OSTI)

that generate large magnetic gradients. In a homogeneous magnetic field, the field lines are parallel; that is, then the field lines converge into the ferromagnet. This convergence forms a shallow magnetic field gradient, to minimize the magnetic potential energy, the field lines exiting one magnet converge into the other magnet

Prentiss, Mara

118

Turbulent diffusion with rotation or magnetic fields  

E-Print Network (OSTI)

The turbulent diffusion tensor describing the evolution of the mean concentration of a passive scalar is investigated for forced turbulence either in the presence of rotation or a magnetic field. With rotation the Coriolis force causes a sideways deflection of the flux of mean concentration. Within the magnetohydrodynamics approximation there is no analogous effect from the magnetic field because the effects on the flow do not depend on the sign of the field. Both rotation and magnetic fields tend to suppress turbulent transport, but this suppression is weaker in the direction along the magnetic field. Turbulent transport along the rotation axis is not strongly affected by rotation, except on shorter length scales, i.e. when the scale of the variation of the mean field becomes comparable with the scale of the energy-carrying eddied.

Brandenburg, Axel; Vasil, Geoffrey M

2009-01-01T23:59:59.000Z

119

External-field-free magnetic biosensor  

SciTech Connect

In this paper, we report a magnetic nanoparticle (MNP) detection scheme without the presence of any external magnetic field. The proposed magnetic sensor uses a patterned groove structure within the sensor so that no external magnetic field is needed to magnetize the MNPs. An example is given based on a giant magnetoresistance (GMR) sensing device with a spin valve structure. For this structure, the detection of MNPs located inside the groove and near the free layer is demonstrated under no external magnetic field. Micromagnetic simulations are performed to calculate the signal to noise level of this detection scheme. A maximum signal to noise ratio (SNR) of 18.6?dB from one iron oxide magnetic nanoparticle with 8?nm radius is achieved. As proof of concept, this external-field-free GMR sensor with groove structure of 200?nm?×?200?nm is fabricated using a photo and an electron beam integrated lithography process. Using this sensor, the feasibility demonstration of the detection SNR of 9.3?dB is achieved for 30??l magnetic nanoparticles suspension (30?nm iron oxide particles, 1?mg/ml). This proposed external-field-free sensor structure is not limited to GMR devices and could be applicable to other magnetic biosensing devices.

Li, Yuanpeng; Wang, Yi; Klein, Todd; Wang, Jian-Ping, E-mail: jpwang@umn.edu [Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, Minnesota 55455 (United States)

2014-03-24T23:59:59.000Z

120

Ultracold Plasma Expansion in a Magnetic Field  

Science Journals Connector (OSTI)

We measure the expansion of an ultracold plasma across the field lines of a uniform magnetic field. We image the ion distribution by extracting the ions with a high-voltage pulse onto a position-sensitive detector. Early in the lifetime of the plasma (magnetic field (up to 70 G). We observe that the expansion velocity scales as B-1/2, explained by a nonlinear ambipolar diffusion model with anisotropic diffusion in two different directions.

X. L. Zhang; R. S. Fletcher; S. L. Rolston; P. N. Guzdar; M. Swisdak

2008-06-13T23:59:59.000Z

Note: This page contains sample records for the topic "magnetic field charged" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

National High Magnetic Field Laboratory - Magnets and Materials...  

NLE Websites -- All DOE Office Websites (Extended Search)

W.D. and Weijers, H.W., Helium gas bubble trapped in liquid helium in high magnetic field, Appl. Phys. Lett., 104, 133511 (2014) read online 2 Bai, H.; Marshall, W.S.; Bird,...

122

Fringe Field Effects on Bending Magnets, Derived for TRANSPORT/TURTLE  

E-Print Network (OSTI)

A realistic magnetic dipole has complex effects on a charged particle near the entrance and exit of the magnet, even with a constant and uniform magnetic field deep within the interior of the magnet. To satisfy Maxwell's equations, the field lines near either end of a realistic magnet are significantly more complicated, yielding non-trivial forces. The effects of this fringe field are calculated to first order, applying both the paraxial and thin lens approximations. We find that, in addition to zeroth order effects, the position of a particle directly impacts the forces in the horizontal and vertical directions.

Blitz, Sam

2013-01-01T23:59:59.000Z

123

Proof of the Impossibility of a Classical Action Principle for Magnetic Monopoles and Charges without Subsidiary Conditions  

Science Journals Connector (OSTI)

A proof is given that no action principle exists for the classical electromagnetic field when its sources are both charged particles and magnetic monopoles unless an extra condition, not derivable from the action principle, is assumed. The extra condition is that charges never touch magnetic monopoles. The Lorentz force law predicts that a charge and a magnetic monopole approaching each other along a straight line will collide. Since the Lorentz force law can only be gotten from an action principle with the aid of this extra condition, the necessary extra condition is in contradiction to the law derived with its help. Thus there is no satisfactory action principle for the classical electromagnetic field if both charges and magnetic monopoles exist. The foregoing provides an aesthetic argument against the existence of magnetic monopoles. An action principle has then been constructed using the extra condition. It is analogous to the usual action principle for (charge-only) electromagnetic theory, but J?A? is replaced by J?R??K?T? where J? and K? are the 4-dimensional current and magnetic monopole densities, respectively, and R? and T? are gaugeless "effective potentials." Electromagnetic theory is formulated in a gaugeless way in terms of these effective potentials in the Appendix.

David Rosenbaum

1966-07-29T23:59:59.000Z

124

ASYMMETRIC DIFFUSION OF MAGNETIC FIELD LINES  

SciTech Connect

Stochasticity of magnetic field lines is important for particle transport properties. Magnetic field lines separate faster than diffusively in turbulent plasma, which is called superdiffusion. We discovered that this superdiffusion is pronouncedly asymmetric, so that the separation of field lines along the magnetic field direction is different from the separation in the opposite direction. While the symmetry of the flow is broken by the so-called imbalance or cross-helicity, the difference between forward and backward diffusion is not directly due to imbalance, but a non-trivial consequence of both imbalance and non-reversibility of turbulence. The asymmetric diffusion perpendicular to the mean magnetic field entails a variety of new physical phenomena, such as the production of parallel particle streaming in the presence of perpendicular particle gradients. Such streaming and associated instabilities could be significant for particle transport in laboratory, space, and astrophysical plasmas.

Beresnyak, Andrey [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

2013-04-20T23:59:59.000Z

125

Magnetic fields from second-order interactions  

E-Print Network (OSTI)

It is well known that when two types of perturbations interact in cosmological perturbation theory, the interaction may lead to the generation of a third type. In this article we discuss the generation of magnetic fields from such interactions. We determine conditions under which the interaction of a first-order magnetic field with a first-order scalar-or vector-, or tensor-perturbations would lead to the generation of second order magnetic field. The analysis is done in a covariant-index-free approach, but could be done in the standard covariant indexed-approach.

Bob Osano

2014-03-21T23:59:59.000Z

126

Electrical properties of chain microstructure magnetic emulsions in magnetic field  

E-Print Network (OSTI)

The work deals with the experimental study of the emulsion whose dispersion medium is a magnetic fluid while the disperse phase is formed by a glycerin-water mixture. It is demonstrated that under effect of a magnetic field chain aggregates form from the disperse phase drops. Such emulsion microstructure change affects its macroscopic properties. The emulsion dielectric permeability and specific electrical conductivity have been measured. It is demonstrated that under the effect of relatively weak external magnetic fields (~ 1 kA/m) the emulsion electrical parameters may change several fold. The work theoretically analyzes the discovered regularities of the emulsion electrical properties.

Arthur Zakinyan; Yuri Dikansky; Marita Bedzhanyan

2014-02-05T23:59:59.000Z

127

Reverse?field reciprocity for conducting specimens in magnetic fields  

Science Journals Connector (OSTI)

A new static?electromagnetic reciprocity principle is presented extending ordinary resistive reciprocity to the case of nonzero magnetic fields by requiring the magnetic field to be reversed when the reciprocal measurement is made. The principle is supported by measurements on various types of specimens including those which exhibit the quantum?Hall effect. A derivation using elementary electromagnetic theory shows that the principle will hold provided only that the specimen is electrically linear (Ohmic) and that the Onsager form for the conductivity tensor applies throughout. The principle has important implications for electrical measurements on semiconductors in applied?magnetic fields.

H. H. Sample; W. J. Bruno; S. B. Sample; E. K. Sichel

1987-01-01T23:59:59.000Z

128

Magnetic Vortex Core Reversal by Low-Field Excitations  

NLE Websites -- All DOE Office Websites (Extended Search)

Magnetic Vortex Core Reversal by Low-Field Excitations Print In micrometer-sized magnetic thin films, the magnetization typically adopts an in-plane, circular configuration known...

129

National High Magnetic Field Laboratory: Museum of Electricity...  

NLE Websites -- All DOE Office Websites (Extended Search)

high-tech field, gradually being replaced by semiconductors. Related Electricity & Magnetism Pages Magnetic Core Memory: Interactive Java Tutorial Magnetic core memory was...

130

Experiments on Magnetic-Field-Line Reconnection  

Science Journals Connector (OSTI)

In a very large laboratory plasma the process of magnetic-field-line reconnection has been diagnosed carefully. The temporal evolution of a narrow (?3c?pe) neutral layer with Petschek slow shocks is observed. Electrostatic fields are found to be as important as induced electric fields.

R. L. Stenzel and W. Gekelman

1979-04-16T23:59:59.000Z

131

Observation of Dirac Monopoles in a Synthetic Magnetic Field  

E-Print Network (OSTI)

Magnetic monopoles --- particles that behave as isolated north or south magnetic poles --- have been the subject of speculation since the first detailed observations of magnetism several hundred years ago. Numerous theoretical investigations and hitherto unsuccessful experimental searches have followed Dirac's 1931 development of a theory of monopoles consistent with both quantum mechanics and the gauge invariance of the electromagnetic field. The existence of even a single Dirac magnetic monopole would have far-reaching physical consequences, most famously explaining the quantization of electric charge. Although analogues of magnetic monopoles have been found in exotic spin-ices and other systems, there has been no direct experimental observation of Dirac monopoles within a medium described by a quantum field, such as superfluid helium-3. Here we demonstrate the controlled creation of Dirac monopoles in the synthetic magnetic field produced by a spinor Bose-Einstein condensate. Monopoles are identified, in both experiments and matching numerical simulations, at the termini of vortex lines within the condensate. By directly imaging such a vortex line, the presence of a monopole may be discerned from the experimental data alone. These real-space images provide conclusive and long-awaited experimental evidence of the existence of Dirac monopoles. Our result provides an unprecedented opportunity to observe and manipulate these quantum-mechanical entities in a controlled environment.

M. W. Ray; E. Ruokokoski; S. Kandel; M. Möttönen; D. S. Hall

2014-08-13T23:59:59.000Z

132

Review: Magnetic fields of O stars  

E-Print Network (OSTI)

Since 2002, strong, organized magnetic fields have been firmly detected at the surfaces of about 10 Galactic O-type stars. In this paper I will review the characteristics of the inferred fields of individual stars, as well as the overall population. I will discuss the extension of the 'magnetic desert', first inferred among the A-type stars, to O stars up to 60 solar masses. I will discuss the interaction of the winds of the magnetic stars with the fields above their surfaces, generating complex 'dynamical magnetosphere' structures detected in optical and UV lines, and in X-ray lines and continuum. Finally, I will discuss the detection of a small number of variable O stars in the LMC and SMC that exhibit spectral characteristics analogous to the known Galactic magnetic stars, and that almost certainly represent the first known examples of extra-Galactic magnetic stars.

Wade, G A

2014-01-01T23:59:59.000Z

133

Magnetic Field Measurements and Analysis For an Aladdin Dipole Magnet  

NLE Websites -- All DOE Office Websites (Extended Search)

Field Measurements and Analysis Field Measurements and Analysis For an Aladdin Dipole Magnet by Kenneth M. Thompson Electromagnetic Technology Program Argonne National Laboratory Argonne, 1L 60439 L8-40 November 21, 1985 Table of Contents Summary i A. Introduction *..*.**.***.....****...**.*..*...*..***.......*..... 1 1. Magnet Description 2. Measuring System 3. Data Descriptions 1 1 3 B. Equipment **********************.***.******.*************..******* 5 1. Probe Positioning System a. Description b. Calibration 2. Field Probe a. Calibration b. Probe Center 1. Method 2. Repeatability c. Hall Gaussmeter Parameters 3. Auxiliary Probes 4. Optical Alignment Equipment 5. Power Supply 6. Magnet Cooling Water System 7. Support a. Magnet b. Manipulator 5 5 7 7 8 9 9 9 10 10 13 13

134

Wire codes, magnetic fields, and childhood cancer  

SciTech Connect

Childhood cancer has been modestly associated with wire codes, an exposure surrogate for power frequency magnetic fields, but less consistently with measured fields. The authors analyzed data on the population distribution of wire codes and their relationship with several measured magnetic field metrics. In a given geographic area, there is a marked trend for decreased prevalence from low to high wire code categories, but there are differences between areas. For average measured fields, there is a positive relationship between the mean of the distributions and wire codes but a large overlap among the categories. Better discrimination is obtained for the extremes of the measurement values when comparing the highest and the lowest wire code categories. Instability of measurements, intermittent fields, or other exposure conditions do not appear to provide a viable explanation for the differences between wire codes and magnetic fields with respect to the strength and consistency of their respective association with childhood cancer.

Kheifets, L.I.; Kavet, R.; Sussman, S.S. [Electric Power Research Inst., Palo Alto, CA (United States)] [Electric Power Research Inst., Palo Alto, CA (United States)

1997-05-01T23:59:59.000Z

135

MRS photodiode in strong magnetic field  

SciTech Connect

The experimental results on the performance of the MRS (Metal/Resistor/Semiconductor) photodiode in the strong magnetic field of 4.4T, and the possible impact of the quench of the magnet at 4.5T on sensor's operation are reported.

Beznosko, D.; Blazey, G.; Dyshkant, A.; Francis, K.; Kubik, D.; Rykalin, V.; /Northern Illinois U.; Tartaglia, M.A.; /Fermilab; Zutshi, v.; /Northern Illinois U.

2004-12-01T23:59:59.000Z

136

Magnetic Field Lines in Fusion Plasmas  

Science Journals Connector (OSTI)

Study of mappings as a part of Hamiltonian dynamics of magnetic field lines in plasmas were initiated by the research...1.... Actually, a fusion research in early sixties gave a huge impact on the development of ...

Sadrilla S. Abdullaev

2006-01-01T23:59:59.000Z

137

National High Magnetic Field Laboratory - Electron Interaction...  

NLE Websites -- All DOE Office Websites (Extended Search)

c). Plot of the CNT sample conductance versus the gate voltage and the axial magnetic field. A dark arrow indicates the value of B0 , where the energy gap has a minimum (metallic...

138

National High Magnetic Field Laboratory: Superconducting Wire  

NLE Websites -- All DOE Office Websites (Extended Search)

of the particles has an effect on the pinning along various directions of magnetic field lines. The conductive capacity of 2G HTS wire is similarly affected by the...

139

Static High Magnetic Fields and Materials Science  

Science Journals Connector (OSTI)

Like temperature or pressure, the magnetic field is one of the important thermodynamic parameters that are used to change the inner energies of materials. Materials are essentially composed of atomic nuclei an...

M. Motokawa; K. Watanabe; F. Herlach

2002-01-01T23:59:59.000Z

140

Magnetic Charge of the Stark States of Hydrogen Atoms  

E-Print Network (OSTI)

It is conjectured that Stark states of excited hydrogen atom posses magnetic charge for which the quantum mechanical operator is $${\\cal G}_{op} = {e\\over \\hbar} (\\vec\\sigma\\cdot\\vec A)$$ where $\\vec A$ is the Runge-Lenz vector. The expectation value $g$ of this operator for Stark states is found to be $$ g = e(n_1-n_2)$$ which obeys a Dirac-Saha type quantization formula $${eg\\over c} = (n_1-n_2)\\alpha$$ where $\\alpha$ is the fine structure constant and $n_1$ and $n_2$ are parabolic quantum numbers. An experimental arrangement is outlined to test this conjecture.

T. Pradhan

2008-09-28T23:59:59.000Z

Note: This page contains sample records for the topic "magnetic field charged" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
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141

Magnetic Charge Can Locally Stabilize Kaluza-Klein Bubbles  

E-Print Network (OSTI)

We construct a new 2-parameter family of static topological solitons in 5D minimal supergravity which are endowed with magnetic charge and mass. The solitons are asymptotically ${\\mathbb R}^4\\times S^1$, where the radius of the $S^1$ has a lower bound $R_s\\ge R_{min}$. Setting up initial data on a Cauchy slice at a moment of time symmetry, we demonstrate that if $R_s>R_{min}$ these solitons correspond to a perturbatively stable "small" static bubble as well as an unstable "large" static bubble, whereas if $R_sbubbles. The energetics and thermodynamics of the magnetic black string are then discussed and it is shown that the locally stable bubble is the end point of a phase transition for an appropriate range of black string parameters.

Sean Stotyn; Robert B. Mann

2011-05-10T23:59:59.000Z

142

Magnetic Charge Can Locally Stabilize Kaluza-Klein Bubbles  

E-Print Network (OSTI)

We construct a new 2-parameter family of static topological solitons in 5D minimal supergravity which are endowed with magnetic charge and mass. The solitons are asymptotically ${\\mathbb R}^4\\times S^1$, where the radius of the $S^1$ has a lower bound $R_s\\ge R_{min}$. Setting up initial data on a Cauchy slice at a moment of time symmetry, we demonstrate that if $R_s>R_{min}$ these solitons correspond to a perturbatively stable "small" static bubble as well as an unstable "large" static bubble, whereas if $R_sbubbles. The energetics of the magnetic black string are then discussed and it is shown that the locally stable bubble is the end point of a phase transition for an appropriate range of black string parameters.

Stotyn, Sean

2011-01-01T23:59:59.000Z

143

Magnetic Field Generation by Detonation Waves  

Science Journals Connector (OSTI)

A simple model is given for the spontaneous magnetic field generation by a detonation wave in condensed matter. The field is shown to arise from the noncollinearity of the thermal and electron density gradients near a medium boundary at the detonation shock front. The model allows calculation of approximate values for the field strength at the front and penetration ahead of the detonation wave. For typical explosive media interfaced by air the magnetic field is predicted to lie in the range 0.1 to 15 G.

Michael J. Frankel and Edward T. Toton

1979-12-10T23:59:59.000Z

144

National High Magnetic Field Laboratory: Museum of Electricity...  

NLE Websites -- All DOE Office Websites (Extended Search)

Pages Interactive Java Tutorials: Galvanometer Interactive Java Tutorials: Magnetic Field Lines Around a Wire, I Interactive Java Tutorials: Magnetic Field Lines Around a Wire,...

145

Laminated magnet field coil sheath  

DOE Patents (OSTI)

A method for manufacturing a magnetic cable trim coil in a sheath assembly for use in a cryogenic particle accelerator. A precisely positioned pattern of trim coil turns is bonded to a flexible substrate sheath that is capable of withstanding cryogenic operating conditions. In the method of the invention the flexible substrate sheath, with the trim coil pattern precisely location relative to a bore tube assembly of an accelerator and is then bonded to the bore tube with a tape suitable for cryogenic application. The resultant assembly can be readily handled and installed within an iron magnet yoke assembly of a suitable cryogenic particle accelerator. 1 fig.

Skaritka, J.R.

1987-05-15T23:59:59.000Z

146

Variable-field permanent magnet dipole  

SciTech Connect

A new concept for a variable-field permanent-magnet dipole (VFPMD) has been designed, fabricated, and tested at Los Alamos. The VFPMD is a C-shaped sector magnet with iron poles separated by a large block of magnet material (SmCo). The central field can be continuously varied from 0.07 T to 0.3 T by moving an iron shunt closer or further away from the back of the magnet. The shunt is specially shaped to make the dependence of the dipole field strength on the shunt position as linear as possible. The dipole has a 2.8 cm high by 8 cm wide aperture with {approximately}10 cm long poles.

Barlow, D.B.; Kraus, R.H. Jr.; Meyer, R.E.

1993-10-01T23:59:59.000Z

147

Results of magnetic field measurements of SPring-8 magnets  

SciTech Connect

Magnetic measurements have been performed for all dipoles, quadrupoles and sextupoles of the SPring-8 storage ring. The long flip coil and the rotating coil system were used for the measurements and they were good enough in measurement accuracy. Dispersion of the magnetic length and strength of the multipole fields were found to be within tolerable range for the three types of the magnets. The position of the fiducial points for alignment was measured in the accuracy of better than 20 {micro}m for all the quadrupoles and the sextupoles.

Ohnishi, J.; Kawakami, M.; Fujii, K.; Matsui, S.; Kumagai, N. [SPring-8, Hyogo (Japan)] [SPring-8, Hyogo (Japan)

1996-07-01T23:59:59.000Z

148

Hyperon bulk viscosity in strong magnetic fields  

SciTech Connect

We study the bulk viscosity of neutron star matter including {lambda} hyperons in the presence of quantizing magnetic fields. Relaxation time and bulk viscosity due to both the nonleptonic weak process involving {lambda} hyperons and direct Urca processes are calculated here. In the presence of a strong magnetic field of 10{sup 17} G, the hyperon bulk viscosity coefficient is reduced, whereas bulk viscosity coefficients due to direct Urca processes are enhanced compared with their field free cases when many Landau levels are populated by protons, electrons, and muons.

Sinha, Monika; Bandyopadhyay, Debades [Theory Division and Centre for Astroparticle Physics, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata-700064 (India)

2009-06-15T23:59:59.000Z

149

Circumstellar Magnetic Field Diagnostics from Line Polarization  

E-Print Network (OSTI)

Given that dynamically significant magnetic fields in at least some massive stars have now been measured, our contribution addresses the question, to what extent can fields be directly detected in circumstellar gas? The question speaks directly to the very interesting topic of line-driving physics coupled with magnetized plasmas, and how this coupling produces structure in the wind flow. We focus our attention on weak-field diagnostics. These come in two main types: the Hanle effect, which pertains to coherence effects for linear polarization from line scattering, and the weak longitudinal Zeeman effect, which pertains to circular polarization in lines.

Richard Ignace; Kenneth G. Gayley

2007-08-14T23:59:59.000Z

150

The Onset of Ion Heating During Magnetic Reconnection with a Strong Guide Field  

E-Print Network (OSTI)

The onset of the acceleration of ions during magnetic reconnection is explored via particle-in-cell simulations in the limit of a strong ambient guide field that self-consistently and simultaneously follow the motions of protons and $\\alpha$ particles. Heating parallel to the local magnetic field during reconnection with a guide field is strongly reduced compared with the reconnection of anti-parallel magnetic fields. The dominant heating of thermal ions during guide field reconnection results from pickup behavior of ions during their entry into reconnection exhausts and dominantly produces heating perpendicular rather than parallel to the local magnetic field. Pickup behavior requires that the ion transit time across the exhaust boundary (with a transverse scale of the order of the ion sound Larmor radius) be short compared with the ion cyclotron period. This translates into a threshold in the strength of reconnecting magnetic field that favors the heating of ions with high mass-to-charge. A simulation with ...

Drake, J F

2014-01-01T23:59:59.000Z

151

Stable magnetic fields in stellar interiors  

E-Print Network (OSTI)

We investigate the 50-year old hypothesis that the magnetic fields of the Ap stars are stable equilibria that have survived in these stars since their formation. With numerical simulations we find that stable magnetic field configurations indeed appear to exist under the conditions in the radiative interior of a star. Confirming a hypothesis by Prendergast (1956), the configurations have roughly equal poloidal and toroidal field strengths. We find that tori of such twisted fields can form as remnants of the decay of an unstable random initial field. In agreement with observations, the appearance at the surface is an approximate dipole with smaller contributions from higher multipoles, and the surface field strength can increase with the age of the star. The results of this paper were summarised by Braithwaite & Spruit (2004).

J. Braithwaite; A. Nordlund

2005-10-11T23:59:59.000Z

152

Whistler Modes with Wave Magnetic Fields Exceeding the Ambient Field  

Science Journals Connector (OSTI)

Whistler-mode wave packets with fields exceeding the ambient dc magnetic field have been excited in a large, high electron-beta plasma. The waves are induced with a loop antenna with dipole moment either along or opposite to the dc field. In the latter case the excited wave packets have the topology of a spheromak but are propagating in the whistler mode along and opposite to the dc magnetic field. Field-reversed configurations with net zero helicity have also been produced. The electron magnetohydrodynamics fields are force free, have wave energy density exceeding the particle energy density, and propagate stably at subelectron thermal velocities through a nearly uniform stationary ion density background.

R. L. Stenzel; J. M. Urrutia; K. D. Strohmaier

2006-03-10T23:59:59.000Z

153

National High Magnetic Field Laboratory: Museum of Electricity...  

NLE Websites -- All DOE Office Websites (Extended Search)

of static electrical charges. A French engineer with an interest in electricity and magnetism, Charles-Augustin de Coulomb, developed one of the earliest instruments capable of...

154

National High Magnetic Field Laboratory: Museum of Electricity...  

NLE Websites -- All DOE Office Websites (Extended Search)

which is why it can be used repeatedly after it has been initially charged via friction. Related Electricity & Magnetism Pages Pioneers: Alessandro Volta Timeline: 1750 1774...

155

Magnetic field stabilization by temperature control of an azimuthally varying field cyclotron magnet  

SciTech Connect

A magnetic field drift, gradual decrease of the order of 10{sup -4} in several tens of hours, was observed with the beam intensity decrease in an operation of an azimuthally varying field (AVF) cyclotron. From our experimental results, we show that the temperature increase of the magnet iron by the heat transfer from the excitation coils can induce such change of the magnetic field as to deteriorate the beam quality. The temperature control of the magnet iron was realized by thermal isolation between the main coil and the yoke and by precise control of the cooling water temperature of the trim coils attached to the pole surfaces in order to prevent temperature change of the magnet iron. The magnetic field stability of {+-}5x10{sup -6} and the beam intensity stability of {+-}2% have been achieved by this temperature control.

Okumura, S.; Arakawa, K.; Fukuda, M.; Nakamura, Y.; Yokota, W.; Ishimoto, T.; Kurashima, S.; Ishibori, I.; Nara, T.; Agematsu, T.; Sano, M.; Tachikawa, T. [Japan Atomic Energy Research Institute (JAERI), 1233 Watanuki, Takasaki, Gunma 370-1292 (Japan); Sumitomo Heavy Industries, Ltd. (SHI), 5-2 Soubiraki, Niihama, Ehime 792-8588 (Japan)

2005-03-01T23:59:59.000Z

156

Nonlinear electron acoustic waves in presence of shear magnetic field  

SciTech Connect

Nonlinear electron acoustic waves are studied in a quasineutral plasma in the presence of a variable magnetic field. The fluid model is used to describe the dynamics of two temperature electron species in a stationary positively charged ion background. Linear analysis of the governing equations manifests dispersion relation of electron magneto sonic wave. Whereas, nonlinear wave dynamics is being investigated by introducing Lagrangian variable method in long wavelength limit. It is shown from finite amplitude analysis that the nonlinear wave characteristics are well depicted by KdV equation. The wave dispersion arising in quasineutral plasma is induced by transverse magnetic field component. The results are discussed in the context of plasma of Earth's magnetosphere.

Dutta, Manjistha; Khan, Manoranjan [Department of Instrumentation Science, Jadavpur University, Kolkata 700 032 (India)] [Department of Instrumentation Science, Jadavpur University, Kolkata 700 032 (India); Ghosh, Samiran [Department of Applied Mathematics, University of Calcutta 92, Acharya Prafulla Chandra Road, Kolkata 700 009 (India)] [Department of Applied Mathematics, University of Calcutta 92, Acharya Prafulla Chandra Road, Kolkata 700 009 (India); Chakrabarti, Nikhil [Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700 064 (India)] [Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700 064 (India)

2013-12-15T23:59:59.000Z

157

Gravity Probe B Gyroscope charge control using field?emission cathodes  

Science Journals Connector (OSTI)

We propose and test a method for controlling the charging of the Gravity Probe B(GP?B) electrostatically suspended gyroscopes using electrons generated by field emissioncathodes. The GP?B GyroscopeExperiment is designed to measure for the first time the geodetic and the frame?dragging effects predicted by Einstein’s general theory of relativity. The expected accuracy of ?0.3 marcsec/yr (10?11 deg/h) will allow for a 0.01% measurement of the geodetic effect and a 1% measurement of the frame?dragging effect. Gyroscope charging is caused by cosmic radiation by field emission and by the separation of dissimilar metals. The expected charging rate for the gyroscopes is ?1 nC/yr and consequently above the 50 pC limit dictated by disturbing torque considerations. The present charge control technique is based on ultraviolet photoemission of electrons from both the gyroscope and an auxiliary electrode. Experiments have shown this method to be effective at room temperature in ground testing and calculations indicate that it is suitable for charge control in orbit. As an alternative we demonstrate the use of Spindt?type field emissioncathodes for the control of the positive charges on the gyroscopes by using a 10?000 tip emitter array produced by SRI International. The device requirements are (a) stable and reliable operation over two years at 2 K and 1.5×10?9 Pa (b) average power dissipation in the device of less than 50 ?W (c) peak emission current of 1–100 pA (d) dimensions less than 2 mm (e) magnetization less than 10?8 G (f) electric field at the gyroscope less than 104 V/m. The control of negative charges on the gyroscope is achievable by operating in a regime in which the secondary electron emission coefficient is greater than unity.

Saps Buchman; Theodore Quinn; G. M. Keiser; Dale Gill

1993-01-01T23:59:59.000Z

158

http://sunearthday.nasa.gov Exploring Magnetic Field Lines  

E-Print Network (OSTI)

http://sunearthday.nasa.gov Exploring Magnetic Field Lines About this Activity When discussing". Left: Two participants tracing magnetic field lines. Below: Magnetic field line tracings of a bar more field lines. Public Outreach - Make and Take Activities What You'll Need Alnico bar magnets 1

159

Lesson Summary Students will learn about the magnetic fields of  

E-Print Network (OSTI)

Knowledge & Skills Understanding of: · Magnetic field lines · Magnetic field strength decreases class period Materials per student · NASA STERO mission story · Diagrams of the magnetic field linesLesson Summary Students will learn about the magnetic fields of the Sun and Earth. This activity

Mojzsis, Stephen J.

160

Computing nonlinear force free coronal magnetic fields  

E-Print Network (OSTI)

Knowledge of the structure of the coronal magnetic field is important for our understanding of many solar activity phenomena, e.g. flares and CMEs. However, the direct measurement of coronal magnetic fields is not possible with present methods, and therefore the coronal field has to be extrapolated from photospheric measurements. Due to the low plasma beta the coronal magnetic field can usually be assumed to be approximately force free, with electric currents flowing along the magnetic field lines. There are both observational and theoretical reasons which suggest that at least prior to an eruption the coronal magnetic field is in a nonlinear force free state. Unfortunately the computation of nonlinear force free fields is way more difficult than potential or linear force free fields and analytic solutions are not generally available. We discuss several methods which have been proposed to compute nonlinear force free fields and focus particularly on an optimization method which has been suggested recently. We compare the numerical performance of a newly developed numerical code based on the optimization method with the performance of another code based on an MHD relaxation method if both codes are applied to the reconstruction of a semi-analytic nonlinear force-free solution. The optimization method has also been tested for cases where we add random noise to the perfect boundary conditions of the analytic solution, in this way mimicking the more realistic case where the boundary conditions are given by vector magnetogram data. We find that the convergence properties of the optimization method are affected by adding noise to the boundary data and we discuss possibilities to overcome this difficulty.

T. Wiegelmann; T. Neukirch

2008-01-21T23:59:59.000Z

Note: This page contains sample records for the topic "magnetic field charged" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Iron Lines in Superstrong Magnetic Fields  

Science Journals Connector (OSTI)

The possibility of observing atomic lines in the x-ray spectra of strongly magnetized accreting neutron stars is discussed. For magnetic field strengths ranging from 1011-1014 G, both the energies and oscillator strengths of Fe XXVI lines are calculated quantitatively. These lines are expected to be highest in energy, and should dominate at source temperatures kT?10-30 keV.

H. Ruder; G. Wunner; H. Herold; J. Trümper

1981-06-29T23:59:59.000Z

162

Diffusive processes in a stochastic magnetic field  

Science Journals Connector (OSTI)

The statistical representation of a fluctuating (stochastic) magnetic field configuration is studied in detail. The Eulerian correlation functions of the magnetic field are determined, taking into account all geometrical constraints: these objects form a nondiagonal matrix. The Lagrangian correlations, within the reasonable Corrsin approximation, are reduced to a single scalar function, determined by an integral equation. The mean square perpendicular deviation of a geometrical point moving along a perturbed field line is determined by a nonlinear second-order differential equation. The separation of neighboring field lines in a stochastic magnetic field is studied. We find exponentiation lengths of both signs describing, in particular, a decay (on the average) of any initial anisotropy. The vanishing sum of these exponentiation lengths ensures the existence of an invariant which was overlooked in previous works. Next, the separation of a particle’s trajectory from the magnetic field line to which it was initially attached is studied by a similar method. Here too an initial phase of exponential separation appears. Assuming the existence of a final diffusive phase, anomalous diffusion coefficients are found for both weakly and strongly collisional limits. The latter is identical to the well known Rechester-Rosenbluth coefficient, which is obtained here by a more quantitative (though not entirely deductive) treatment than in earlier works.

Hai-Da Wang; M. Vlad; E. Vanden Eijnden; F. Spineanu; J. H. Misguich; R. Balescu

1995-05-01T23:59:59.000Z

163

Bound states in a strong magnetic field  

SciTech Connect

We expect a strong magnetic field to be produced in the perpendicular direction to the reaction plane, in a noncentral heavy-ion collision . The strength of the magnetic field is estimated to be eB{approx}m{sup 2}{sub {pi}}{approx} 0.02 GeV{sup 2} at the RHIC and eB{approx} 15m{sup 2}{sub {pi}}{approx} 0.3 GeV{sup 2} at the LHC. We investigate the effects of the magnetic field on B{sup 0} and D{sup 0} mesons, focusing on the changes of the energy levels and of the mass of the bound states.

Machado, C. S.; Navarra, F. S.; Noronha, J.; Oliveira, E. G. [Instituto de Fisica, Universidade de Sao Paulo Rua do Matao, Travessa R, 187, 05508-090 Sao Paulo, SP (Brazil); Ferreira Filho, L. G. [Departamento de Matematica e Computacao, Faculdade de Tecnologia, Universidade do Estado do Rio de Janeiro Rodovia Presidente Dutra, km 298, Polo Industrial, CEP 27537-000, Resende, RJ (Brazil)

2013-03-25T23:59:59.000Z

164

ThreeThree--dimensional magnetic fielddimensional magnetic field line reconnection involving fluxline reconnection involving flux  

E-Print Network (OSTI)

ThreeThree--dimensional magnetic fielddimensional magnetic field line reconnection involving helicity) · Relaxation of complex field geometries into simpler ones · Magnetic Field Line Reconnection (2D ~ . magnetic field is measured at 20,000 locations #12;Hodogram of central field line in flux tubes

Shyy, Wei

165

Magnetic-field variance in layered superconductors  

Science Journals Connector (OSTI)

In highly anisotropic or layered high-Tc superconductors with magnetic field along the c axis, both pinning-caused and thermal fluctuations of the highly flexible vortex cores, or of chains of vortex dots, threading the cuperconducting layers may drastically reduce the variance ? of the magnetic-field fluctuation. In contrast, the fluctuations of the averaged flux lines (smoothed over the in-plane penetration depth ?) increase ?. As a consequence, muon-spin-rotation lines may be sharpened not only the thermal motional narrowing, but also by pinning-caused static disorder.

Ernst Helmut Brandt

1991-06-17T23:59:59.000Z

166

Electric Field How does a charge, q1, exert a force on  

E-Print Network (OSTI)

Electric Field How does a charge, q1, exert a force on another charge, q2, when the charges don't touch? The charge, q1, sets up an electric field in its surrounding space This electric field has both magnitude and direction which determine the magnitude and direction of the force acting on q2 #12;Electric

Bertulani, Carlos A. - Department of Physics and Astronomy, Texas A&M University

167

Sensor for detecting changes in magnetic fields  

DOE Patents (OSTI)

A sensor for detecting changes in the magnetic field of the equilibrium-field coil of a Tokamak plasma device comprises a pair of bifilar wires disposed circumferentially, one inside and one outside the equilibrium-field coil. Each is shorted at one end. The difference between the voltages detected at the other ends of the bifilar wires provides a measure of changing flux in the equilibrium-field coil. This difference can be used to detect faults in the coil in time to take action to protect the coil.

Praeg, Walter F. (Palos Park, IL)

1981-01-01T23:59:59.000Z

168

Sensor for detecting changes in magnetic fields  

DOE Patents (OSTI)

A sensor is described for detecting changes in the magnetic field of the equilibrium-field coil of a Tokamak plasma device that comprises a pair of bifilar wires disposed circumferentially, one inside and one outside the equilibrium-field coil. Each is shorted at one end. The difference between the voltages detected at the other ends of the bifilar wires provides a measure of changing flux in the equilibrium-field coil. This difference can be used to detect faults in the coil in time to take action to protect the coil.

Praeg, W.F.

1980-02-26T23:59:59.000Z

169

Electro-Mechanical Resonant Magnetic Field Sensor  

E-Print Network (OSTI)

We describe a new type of magnetic field sensor which is termed an Electro-Mechanical Resonant Sensor (EMRS). The key part of this sensor is a small conductive elastic element with low damping rate and therefore a high Q fundamental mode of frequency $f_1$. An AC current is driven through the elastic element which, in the presence of a magnetic field, causes an AC force on the element. When the frequency of the AC current matches the resonant frequency of the element, maximum vibration of the element occurs and this can be measured precisely by optical means. We have built and tested a model sensor of this type using for the elastic element a length of copper wire of diameter 0.030 mm formed into a loop shape. The wire motion was measured using a light emitting diode photo-transistor assembly. This sensor demonstrated a sensitivity better than 0.001G for an applied magnetic field of $ \\sim 1$G and a good selectivity for the magnetic field direction. The sensitivity can be easily improved by a factor of $\\sim ...

Temnykh, A B; Temnykh, Alexander B.; Lovelace, Richard V. E.

2002-01-01T23:59:59.000Z

170

National High Magnetic Field Laboratory - Science Starts Here...  

NLE Websites -- All DOE Office Websites (Extended Search)

correlated electron systems is neutron scattering, often in conjunction with applied magnetic fields. In his own words My experience at the Magnet Lab gave me an early...

171

National High Magnetic Field Laboratory: Museum of Electricity...  

NLE Websites -- All DOE Office Websites (Extended Search)

navigate the seas, effectively changing the course of history. Related Electricity & Magnetism Pages Museum: Lodestone Timeline: 600 1599 Tutorial: Compasses in Magnetic Fields...

172

High Field Magnet R&D in the USA  

E-Print Network (OSTI)

High Field Magnet R&D in the USA Stephen A. Gourlay magnetLaboratory, Berkeley, CA 94720 USA (telephone: 510-486-7156,

Gourlay, Stephen A.

2003-01-01T23:59:59.000Z

173

Primordial magnetic fields from self-ordering scalar fields  

E-Print Network (OSTI)

A symmetry-breaking phase transition in the early universe could have led to the formation of cosmic defects. Because these defects dynamically excite not only scalar and tensor type cosmological perturbations but also vector type ones, they may serve as a source of primordial magnetic fields. In this study, we calculate the time evolution and the spectrum of magnetic fields that are generated by a type of cosmic defects, called global textures, using the non-linear sigma (NLSM) model. Based on the standard cosmological perturbation theory, we show, both analytically and numerically, that a vector-mode relative velocity between photon and baryon fluids is induced by textures, which inevitably leads to the generation of magnetic fields over a wide range of scales. We find that the amplitude of the magnetic fields is given by $B\\sim{10^{-9}}{((1+z)/10^3)^{-2.5}}({v}/{m_{\\rm pl}})^2({k}/{\\rm Mpc^{-1}})^{3.5}/{\\sqrt{N}}$ Gauss in the radiation dominated era for $k\\lesssim 1$ Mpc$^{-1}$, with $v$ being the vacuum ...

Horiguchi, Kouichirou; Sekiguchi, Toyokazu; Sugiyama, Naoshi

2015-01-01T23:59:59.000Z

174

Circular polarization of obliquely propagating whistler wave magnetic field  

SciTech Connect

The circular polarization of the magnetic field of obliquely propagating whistler waves is derived using a basis set associated with the wave partial differential equation. The wave energy is mainly magnetic and the wave propagation consists of this magnetic energy sloshing back and forth between two orthogonal components of magnetic field in quadrature. The wave electric field energy is small compared to the magnetic field energy.

Bellan, P. M. [Applied Physics, Caltech, Pasadena California 91125 (United States)] [Applied Physics, Caltech, Pasadena California 91125 (United States)

2013-08-15T23:59:59.000Z

175

Non-Employee Static Magnetic Field Questionnaire  

NLE Websites -- All DOE Office Websites (Extended Search)

Occupational Medicine Clinic (OMC) Occupational Medicine Clinic (OMC) Medical Questionnaire for non-BSA Workers/Students who may enter STATIC MAGNETIC FIELDS NAME:_________________ Extension__________ BNL Badge #:_____________ BNL Supervisor_____________ INSTRUCTIONS TO BSA SUPERVISOR or PRECEPTOR: Please print this form and give it to the (non-BSA employee) worker or student for completion. This individual should not give you the completed form, but should instead mail or fax it to OMC. INSTRUCTIONS TO WORKER or STUDENT: The purpose of this questionnaire is to provide the OMC physician at BNL with information about any medical devices or conditions you may have that might affect your ability to safely enter a strong magnetic field, in order to determine whether you can be medically cleared to enter such a field.

176

The ESRF Miniature Pulsed Magnetic Field System  

SciTech Connect

We have developed a portable system to provide pulsed magnetic fields on the ESRF X-ray beamlines. The complete system consists of a power supply, liquid Helium and liquid Nitrogen dewars with a siphon each, control electronics and a double cryostat for separate coil and sample cooling. The liquid nitrogen cooled solenoids reach a maximum field of 30 Tesla for a total pulse duration of one milisecond. They are constructed for optimised cooling rate after the pulse to obtain a high duty cycle, the repetition rate is five pulses per minute at maximum field. The sample is cooled in an independent Helium flow cryostat which is inserted into the bore of the magnet. The flow cryostat has a temperature range from 5 to 250 Kelvin with a direct contact between the sample and Helium flow. This overview gives a general presentation of the system and we will show recent results.

Linden, Peter J. E. M. van der; Strohm, Cornelius; Roth, Thomas; Detlefs, Carsten; Mathon, Olivier [ESRF, 6 rue Jules Horowitz, F-38043 Grenoble (France)

2010-06-23T23:59:59.000Z

177

Magnetic field exposure among utility workers  

SciTech Connect

The Electric and Magnetic Field Measurement Project for Utilities -- the Electric Power Research Institute (EPRI) Electric and Magnetic Field Digital Exposure (EMDEX) Project (the EPRI EMDEX Project) -- was a multifaceted project that entailed technology transfer, measurement protocol design, data management, and exposure assessment analyses. This paper addresses one specific objective of the project: the collection, analysis, and documentation of power-frequency magnetic filed exposures for a diverse population of utility employees at 59 sites in four countries between September, 1988, and September, 1989. Specially designed sampling procedures and data collection protocols were used to ensure uniform implementation across sites. Volunteers within 13 job classifications recorded which of eight work or three nonwork environments they occupied while wearing an EMDEX meter. Approximately 50,000 hours of magnetic field exposure records taken at 10 s intervals were obtained, about 70% of which were from work environments. Exposures and time spent in environments were analyzed by primary work environment, by occupied environment, and by job classification.

Bracken, T.D.; Senior, R.S. [T. Dan Bracken, Inc., Portland, OR (United States); Rankin, R.F. [Applied Research Services, Inc., Lake Oswego, OR (United States); Alldredge, J.R. [Washington State Univ., Pullman, WA (United States); Sussman, S.S. [Electric Power Research Institute, Palo Alto, CA (United States)

1995-09-01T23:59:59.000Z

178

Combined Effects of Unsteady Electric Field and Uniform Magnetic Field on Magnetoelectroconvection in a Poorly Conducting Plasma  

Science Journals Connector (OSTI)

The magnetoelectroconvective instability of a plane horizontal layer of a poorly conducting plasma subjected to a strong nonuniform electric field and uniform magnetic field is investigated in the combined magnetoelectrohydrodynamic approximations when charge formation is produced by this convection. The spatio?temporal variation of electric field density of charge distribution and temperature are found for the quiescent basic state. The influence of combined uniform magnetic field and a time?dependent electric field modulation on the behaviour of a poorly conducting plasma is studied using energy and moment methods along with Galerkin technique. The criterion for the onset of magnetoelectroconvection involving the effects of both strong electric and magnetic fields is computed and the results are compared with these obtained only in the presence of electric field. We found that the combined effect of electric and magnetic fields is more favourable to suppress convection significantly than in the presence of electric field alone. This result is useful in synthesizing smart and strong materials needed for many aeronautical automobile and biomedical engineering applications to minimize the weight and maximize the strength to achieve the sufficient dynamic advantages.

M. S. Gayathri

2006-01-01T23:59:59.000Z

179

Published in Phys: Rev: D 44 3887 \\Gamma 3898 (1991) COULOMB FIELD OF AN ACCELERATED CHARGE  

E-Print Network (OSTI)

Published in Phys: Rev: D 44 3887 \\Gamma 3898 (1991) COULOMB FIELD OF AN ACCELERATED CHARGE Columbus, Ohio 43210 ABSTRACT The Coulomb field of a charge static in an accelerated frame has properties the accelerated charge and the charge induced on the surface whose history is the event horizon. A spectral

Gerlach, Ulrich

180

Charges and Generators of Symmetry Transformations in Quantum Field Theory  

Science Journals Connector (OSTI)

Within the Wightman approach to quantum field theory, we review and clarify the properties of formal charges, defined as space integrals for the fourth component of a local current. The conditions for a formal charge to determine an operator (generator) are discussed, in connection with the well-known theorems of Goldstone and of Coleman. The symmetry transformations generated by this operator—given its existence—are also studied in some detail. For generators in a scattering theory, we prove their additivity and thus provide a simple way to characterize them from their matrix elements between one-particle states. This characterization allows an immediate construction of the unitary operators implementing the symmetry transformations, and implies that all internal symmetry groups are necessarily compact. We also indicate how to construct interacting fields having definite internal quantum numbers. The present status of the proof of Noether's theorem and of its converse is discussed in the light of the rather delicate properties of formal charges.

CLAUDIO A. ORZALESI

1970-10-01T23:59:59.000Z

Note: This page contains sample records for the topic "magnetic field charged" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

Destruction of invariant surfaces and magnetic coordinates for perturbed magnetic fields  

E-Print Network (OSTI)

of Physics. DOI: 10.1063/1.1640379 I. INTRODUCTION As toroidal magnetic field line flow, with non be constructed everywhere.5 The analog of action-angle co- ordinates for magnetic field line flow is straight-field-line, all the magnetic field lines lie on flux surfaces. For a non-integrable field the situ- ation is more

Hudson, Stuart

182

The measurement and analysis of the magnetic field of a synchrotron light source magnet  

E-Print Network (OSTI)

In this thesis a unique system is used to measure the magnetic field of a superconducting synchrotron light source magnet. The magnet measured is a superferric dipole C-magnet designed to produce a magnetic field up to 3 Tesla in magnitude. Its...

Graf, Udo Werner

2012-06-07T23:59:59.000Z

183

Magnetic-Field-Induced Assemblies of Cobalt Nanoparticles  

Science Journals Connector (OSTI)

8 Magnetic fields have also been used to create 2D assemblies of magnetic nanoparticles at the liquid?air interface9 and 1D assembled chains or 2D rings on solid substrates or TEM grids. ... A magnet (Fisher Scientific, Pittsburgh, PA) with a 0.05-Telsa magnetic field strength was placed near the side wall of the glass vial. ... The interparticle magnetic dipole?dipole couplings and the external coupling of the magnetic dipoles to the field favor linear chain growth along the magnetic-field flux lines. ...

Guangjun Cheng; Danilo Romero; Gerald T. Fraser; A. R. Hight Walker

2005-10-12T23:59:59.000Z

184

Magnetic susceptibility and magnetization properties of asymmetric nuclear matter under a strong magnetic field  

E-Print Network (OSTI)

We study the effect of a strong magnetic field on the proton and neutron spin polarization and magnetic susceptibility of asymmetric nuclear matter within a relativistic mean-field approach. It is shown that magnetic fields $B \\sim 10^{16} - 10^{17}$ G have already noticeable effects on the range of densities of interest for the study of the crust of a neutron star. Although the proton susceptibility is larger for weaker fields, the neutron susceptibility becomes of the same order or even larger for small proton fractions and subsaturation densities for $B > 10^{16}$ G. We expect that neutron superfluidity in the crust will be affected by the presence of magnetic fields.

A. Rabhi; M. A. Pérez-García; C. Providência; I. Vidaña

2014-10-10T23:59:59.000Z

185

22Mathematical Model of Magnetic Field Lines -II Magnets have a north and a south  

E-Print Network (OSTI)

22Mathematical Model of Magnetic Field Lines - II Magnets have a north and a south pole. If you and 4 to complete the magnetic field line drawing! Space Math http://spacemath.gsfc.nasa.gov #12 diagram in the First Quadrant into quadrants 2, 3 and 4 to complete the magnetic field line drawing

186

Control of stochasticity in magnetic field lines  

E-Print Network (OSTI)

We present a method of control which is able to create barriers to magnetic field line diffusion by a small modification of the magnetic perturbation. This method of control is based on a localized control of chaos in Hamiltonian systems. The aim is to modify the perturbation locally by a small control term which creates invariant tori acting as barriers to diffusion for Hamiltonian systems with two degrees of freedom. The location of the invariant torus is enforced in the vicinity of the chosen target. Given the importance of confinement in magnetic fusion devices, the method is applied to two examples with a loss of magnetic confinement. In the case of locked tearing modes, an invariant torus can be restored that aims at showing the current quench and therefore the generation of runaway electrons. In the second case, the method is applied to the control of stochastic boundaries allowing one to define a transport barrier within the stochastic boundary and therefore to monitor the volume of closed field lines.

Cristel Chandre; Michel Vittot; Guido Ciraolo; Philippe Ghendrih; Ricardo Lima

2005-04-14T23:59:59.000Z

187

Solar magnetic fields and terrestrial climate  

E-Print Network (OSTI)

Solar irradiance is considered one of the main natural factors affecting terrestrial climate, and its variations are included in most numerical models estimating the effects of natural versus anthropogenic factors for climate change. Solar wind causing geomagnetic disturbances is another solar activity agent whose role in climate change is not yet fully estimated but is a subject of intense research. For the purposes of climate modeling, it is essential to evaluate both the past and the future variations of solar irradiance and geomagnetic activity which are ultimately due to the variations of solar magnetic fields. Direct measurements of solar magnetic fields are available for a limited period, but can be reconstructed from geomagnetic activity records. Here we present a reconstruction of total solar irradiance based on geomagnetic data, and a forecast of the future irradiance and geomagnetic activity relevant for the expected climate change.

Georgieva, Katya; Kirov, Boian

2014-01-01T23:59:59.000Z

188

Recycling of the Solar Corona's Magnetic Field  

Science Journals Connector (OSTI)

Magnetic fields play a dominant role in the atmospheres of the Sun and other Sun-like stars. Outside sunspot regions, the photosphere of the so-called quiet Sun contains myriads of small-scale magnetic concentrations, with strengths ranging from the detection limit of ~1016 Mx up to ~3 ? 1020 Mx. The tireless motion of these magnetic flux concentrations, along with the continual appearance and disappearance of opposite-polarity pairs of fluxes, releases a substantial amount of energy that may be associated with a whole host of physical processes in the solar corona, not least the enigma of coronal heating. We find here that the timescale for magnetic flux to be remapped in the quiet-Sun corona is, surprisingly, only 1.4 hr (around 1/10 of the photospheric flux recycling time), implying that the quiet-Sun corona is far more dynamic than previously thought. Besides leading to a fuller understanding of the origins of magnetically driven phenomena in our Sun's corona, such a process may also be crucial for the understanding of stellar atmospheres in general.

R. M. Close; C. E. Parnell; D. W. Longcope; E. R. Priest

2004-01-01T23:59:59.000Z

189

Coulomb gaps in a strong magnetic field  

Science Journals Connector (OSTI)

We report on a study of interaction effects in the tunneling density of states of a disordered two-dimensional electron gas in the strong magnetic field limit where only the lowest Landau level is occupied. Interactions in the presence of disorder are accounted for by performing finite-size self-consistent Hartree-Fock calculations. We find evidence for the formation of a pseudogap with a tunneling density of states which vanishes at the Fermi energy.

S.-R. Eric Yang and A. H. MacDonald

1993-06-28T23:59:59.000Z

190

Response of plastic scintillators in magnetic fields  

SciTech Connect

The dependence of the light yield on magnetic field has been measured up to 0.45 T for the plastic scintillators NE-102A, SCSN-38 and Polivar. The scintillators were excited by 25 MeV protons, 5.9 keV X-rays and UV light. When excited with ionizing radiation an increase of light yield is observed. For SCSN-38 of 2.7 mm thickness it amounts to 0.3%, 0.9%, 1.1% and 3.3% at 1, 10, 100 and 450 mT respectively. NE-102A behaves similar, whereas a PMMA based scintillator shows a stronger field dependence.

Blomker, D.; Holm, V. (Inst. Experimentalphysik, Universitat Hamburg, Luruper Chaussee 149, D-2000 Hamburg 50 (DE)); Klanner, R.; Krebs, B. (Deutsches Elektronen-Synchroton, Notkstr. 85, D-2000 Hamburg 52 (DE))

1990-04-01T23:59:59.000Z

191

The Search for a Primordial Magnetic Field  

E-Print Network (OSTI)

Magnetic fields appear wherever plasma and currents can be found. As such, they thread through all scales in Nature. It is natural, therefore, to suppose that magnetic fields might have been formed within the high temperature environments of the big bang. Such a primordial magnetic field (PMF) would be expected to arise from and/or influence a variety of cosmological phenomena such as inflation, cosmic phase transitions, big bang nucleosynthesis, the cosmic microwave background (CMB) temperature and polarization anisotropies, the cosmic gravity wave background, and the formation of large-scale structure. In this review, we summarize the development of theoretical models for analyzing the observational consequences of a PMF. We also summarize the current state of the art in the search for observational evidence of a PMF. In particular we review the framework needed to calculate the effects of a PMF power spectrum on the CMB and the development of large scale structure. We summarize the current constraints on the PMF amplitude $B_\\lambda$ and the power spectral index $n_B$ and discuss prospects for better determining these quantities in the near future.

Dai G. Yamazaki; Toshitaka Kajino; Grant J. Mathew; Kiyotomo Ichiki

2012-04-16T23:59:59.000Z

192

Improved Magnetic Field Generation Efficiency and Higher Temperature Spheromak Plasmas  

SciTech Connect

New understanding of the mechanisms governing the observed magnetic field generation limits on the sustained spheromak physics experiment has been obtained. Extending the duration of magnetic helicity injection during the formation of a spheromak and optimizing the ratio of injected current to bias flux produce higher magnetic field plasmas with record spheromak electron temperatures. To explore magnetic field buildup efficiency limits, the confinement region geometry was varied resulting in improved field buildup efficiencies.

Wood, R D; Hill, D N; McLean, H S; Hooper, E B; Hudson, B F; Moller, J M; Romero-Talamas, C A

2008-09-15T23:59:59.000Z

193

Improved magnetic field generation efficiency and higher temperature spheromak plasmas  

Science Journals Connector (OSTI)

New understanding of the mechanisms governing the observed magnetic field generation limits on the sustained spheromak physics experiment has been obtained. Extending the duration of magnetic helicity injection during the formation of a spheromak and optimizing the ratio of injected current to bias flux produce higher magnetic field plasmas with record spheromak electron temperatures. To explore magnetic field buildup efficiency limits, the confinement region geometry was varied resulting in improved field buildup efficiencies.

R.D. Wood; D.N. Hill; H.S. McLean; E.B. Hooper; B.F. Hudson; J.M. Moller; C.A. Romero-Talamás

2009-01-01T23:59:59.000Z

194

ECE 390 Electric & Magnetic Fields Catalog Description: Static and quasi-static electric and magnetic fields.  

E-Print Network (OSTI)

ECE 390 ­ Electric & Magnetic Fields Catalog Description: Static and quasi-static electric), A. Jander (secondary) Course Content: · Introduction, review of vector analysis · Static electric fields in free space: Coulomb's law, Gauss's law, and electric potential, electric dipole · Static

195

National High Magnetic Field Laboratory - Science Starts Here...  

NLE Websites -- All DOE Office Websites (Extended Search)

a better and much more productive scientist. I had the opportunity to learn unique high magnetic field experimental techniques from the top researchers in the field, in a...

196

Magnetic Field based Heading Estimation for Pedestrian Navigation Environments  

E-Print Network (OSTI)

Magnetic Field based Heading Estimation for Pedestrian Navigation Environments Muhammad Haris Afzal held devices, these other sources are accelerometers for roll and pitch estimates and magnetic field sensors for the heading. In order to utilize the magnetic field sensors for heading estimation

Calgary, University of

197

2.6 ELECTRIC AND MAGNETIC FIELDS Introduction  

E-Print Network (OSTI)

325 §2.6 ELECTRIC AND MAGNETIC FIELDS Introduction In electromagnetic theory the mks system MKS units Replacement symbol GAUSSIAN units E (Electric field) volt/m E statvolt/cm B (Magnetic field gauss-cm V (Electric potential) volt V statvolt (Dielectric constant) 4 µ (Magnetic permeability) 4µ c2

California at Santa Cruz, University of

198

Studies of Avalanche Photodiode Performance in a High Magnetic Field  

E-Print Network (OSTI)

We report the results of exposing a Hamamatsu avalanche photodiode (APD) to a 7.9 Tesla magnetic field. The effect of the magnetic field on the gain of the APD is shown and discussed. We find APD gain to be unaffected in the presence of such a magnetic field.

J. Marler; T. McCauley; S. Reucroft; J. Swain; D. Budil; S. Kolaczkowski

2000-01-04T23:59:59.000Z

199

Molecular Lines as Diagnostics of Solar and Stellar Magnetic Fields  

E-Print Network (OSTI)

Molecular Lines as Diagnostics of Solar and Stellar Magnetic Fields S.V. Berdyugina1, S.K. Solanki2 of different OH lines are reproduced without invoking any free parameters, except the magnetic field strength to significant improvements in the deduced magnetic field vector. Here we investigate how molecular lines can

Berdyugina, Svetlana

200

Magnetic field topology and field lines structure in the Dynamic Ergodic Divertor of TEXTOR-94  

Science Journals Connector (OSTI)

An analytical model of the magnetic field perturbations and the mapping technique to study field line dynamics in an ergodic divertor tokamak are developed. The analytical formulas for the vacuum magnetic field p...

S. S. Abdullaev; K. H. Finken; A. Kaleck…

1998-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "magnetic field charged" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

Some Comments About Correlations Between Magnetic Field and Velocity, Magnetic Field and Line Intensity in the Undisturbed Photosphere  

Science Journals Connector (OSTI)

Test cross-correlation functions between the magnetic field recordings and the sight-line velocity recordings with East and West relative ... the deviations of the absolute value of the magnetic-field strength |H

G. Y. Vassilyeva; A. K. Tchandaev

1968-01-01T23:59:59.000Z

202

Deconfinement to quark matter in neutron stars - The influence of strong magnetic fields  

SciTech Connect

We use an extended version of the hadronic SU(3) non-linear realization of the sigma model that also includes quarks to study hybrid stars. Within this approach, the degrees of freedom change naturally as the temperature/density increases. Different prescriptions of charge neutrality, local and global, are tested and the influence of strong magnetic fields and the anomalous magnetic moment on the particle population is discussed.

Dexheimer, V. [UFSC, Florianopolis, Brazil and Gettysburg College, Gettysburg, PA (Brazil); Negreiros, R. [UFF, Niteroi (Brazil) and FIAS - Johann Wolfgang Goethe University, Frankfurt (Germany); Schramm, S. [FIAS - Johann Wolfgang Goethe University, Frankfurt (Germany); Hempel, M. [University of Basel, Basel (Switzerland)

2013-03-25T23:59:59.000Z

203

Interaction of magnetic resonators studied by the magnetic field enhancement  

SciTech Connect

It is the first time that the magnetic field enhancement (MFE) is used to study the interaction of magnetic resonators (MRs), which is more sensitive than previous parameters–shift and damping of resonance frequency. To avoid the coherence of lattice and the effect of Bloch wave, the interaction is simulated between two MRs with same primary phase when the distance is changed in the range of several resonance wavelengths, which is also compared with periodic structure. The calculated MFE oscillating and decaying with distance with the period equal to resonance wavelength directly shows the retardation effect. Simulation also shows that the interaction at normal incidence is sensitive to the phase correlation which is related with retardation effect and is ultra-long-distance interaction when the two MRs are strongly localized. When the distance is very short, the amplitude of magnetic resonance is oppressed by the strong interaction and thus the MFE can be much lower than that of single MR. This study provides the design rules of metamaterials for engineering resonant properties of MRs.

Hou, Yumin, E-mail: ymhou@pku.edu.cn [State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871 (China)] [State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871 (China)

2013-12-15T23:59:59.000Z

204

Photon emission in a constant magnetic field in 2+1 dimensional space-time  

E-Print Network (OSTI)

We calculate by the proper-time method the amplitude of the two-photon emission by a charged fermion in a constant magnetic field in (2+1)-dimensional space-time. The relevant dynamics reduces to that of a supesymmetric quantum-mechanical system with one bosonic and one fermionic degrees of freedom.

J. T. S. Amaral; S. I. Zlatev

2005-11-01T23:59:59.000Z

205

How to use magnetic field information for coronal loop identification?  

E-Print Network (OSTI)

The structure of the solar corona is dominated by the magnetic field because the magnetic pressure is about four orders of magnitude higher than the plasma pressure. Due to the high conductivity the emitting coronal plasma (visible e.g. in SOHO/EIT) outlines the magnetic field lines. The gradient of the emitting plasma structures is significantly lower parallel to the magnetic field lines than in the perpendicular direction. Consequently information regarding the coronal magnetic field can be used for the interpretation of coronal plasma structures. We extrapolate the coronal magnetic field from photospheric magnetic field measurements into the corona. The extrapolation method depends on assumptions regarding coronal currents, e.g. potential fields (current free) or force-free fields (current parallel to magnetic field). As a next step we project the reconstructed 3D magnetic field lines on an EIT-image and compare with the emitting plasma structures. Coronal loops are identified as closed magnetic field lines with a high emissivity in EIT and a small gradient of the emissivity along the magnetic field.

T. Wiegelmann; B. Inhester; A. Lagg; S. K. Solanki

2008-01-30T23:59:59.000Z

206

Relationship between the shape of equilibrium magnetic surfaces and the magnetic field strength  

SciTech Connect

A local analysis of the magnetic field near an equilibrium magnetic surface shows that there is generally no relationship between the magnetic field strength and the shape of the surface. However, the relationship exists under additional requirements such as the absence of the toroidal current, symmetry conservation, and the conservation of the magnetic field strength distribution on the nearest surface. An equilibrium magnetic surface can be calculated by specifying three functions of two angular variables-the magnetic field strength, the periodic component of the magnetic potential, and the mean curvature of the surface.

Skovoroda, A. A. [Russian Research Centre Kurchatov Institute, Nuclear Fusion Institute (Russian Federation)

2007-07-15T23:59:59.000Z

207

Photon Magnetic Moment and Vacuum Magnetization in an Asymptotically Large Magnetic Field  

E-Print Network (OSTI)

We consider the effect of the photon radiative correction on the vacuum energy in a superstrong magnetic field. The notion of a photon anomalous magnetic moment is analyzed and its connection with the quasiparticle character of the electromagnetic radiation is established. In the infrared domain the magnetic moment turns out to be a vector with two orthogonal components in correspondence with the cylindrical symmetry imposed by the external field. The possibility of defining such quantity in the high energy limit is studied as well. Its existence suggests that the electromagnetic radiation is a source of magnetization to the whole vacuum and thus its electron-positron zero-point energy is slightly modified. The corresponding contribution to the vacuum magnetization density is determined by considering the individual contribution of each vacuum polarization eigenmode in the Euler-Heisenberg Lagrangian. A paramagnetic response is found in one of them, whereas the remaining ones are diamagnetic. Additional issues concerning the transverse pressures are analyzed.

Selym Villalba Chavez

2009-10-27T23:59:59.000Z

208

QCD in magnetic fields: from Hofstadter's butterfly to the phase diagram  

E-Print Network (OSTI)

I revisit the problem of a charged particle on a two-dimensional lattice immersed in a constant (electro)magnetic field, and discuss the energy spectrum - Hofstadter's butterfly - from a new, quantum field theoretical perspective. In particular, I point out that there is an intricate interplay between a) the structure of the butterfly at low magnetic flux, b) the absence of asymptotic freedom in QED and c) the enhancement of the quark condensate by a magnetic field at zero temperature. I proceed to discuss the response of the QCD condensate to the magnetic field at nonzero temperatures in four space-time dimensions, present the resulting phase diagram and compare it to low-energy model predictions.

Endrodi, G

2014-01-01T23:59:59.000Z

209

A study of neutral particle decay in magnetic field with the "Worldline Instanton" approach  

E-Print Network (OSTI)

We study the process of neutrino decay to electron and $W$-boson in the external magnetic field using the semiclassical "worldline instanton" approach. Being interested only in the leading exponential factor, we make calculations in a toy model, treating all particles as scalars. This calculation determines the effective threshold energy of the reaction as a function of the magnetic field. Possible astrophysical applications are discussed. It is emphasized that the method is general and is applicable to a decay of an arbitrary neutral particle into charged ones in the external electromagnetic field.

Petr Satunin

2014-07-24T23:59:59.000Z

210

Rotating-frame gradient fields for magnetic resonance imaging and nuclear magnetic resonance in low fields  

DOE Patents (OSTI)

A system and method for Fourier encoding a nuclear magnetic resonance (NMR) signal is disclosed. A static magnetic field B.sub.0 is provided along a first direction. An NMR signal from the sample is Fourier encoded by applying a rotating-frame gradient field B.sub.G superimposed on the B.sub.0, where the B.sub.G comprises a vector component rotating in a plane perpendicular to the first direction at an angular frequency .omega.in a laboratory frame. The Fourier-encoded NMR signal is detected.

Bouchard, Louis-Serge; Pines, Alexander; Demas, Vasiliki

2014-01-21T23:59:59.000Z

211

Maintaining the closed magnetic-field-line topology of a field-reversed configuration (FRC)  

E-Print Network (OSTI)

1 Maintaining the closed magnetic-field-line topology of a field-reversed configuration (FRC, WA 98052 Abstract The effects on magnetic-field-line structure of adding various static transverse introduce pronounced shear. #12;2 I. Introduction Magnetic field lines are closed. Where closure occurs

212

Laser or charged-particle-beam fusion reactor with direct electric generation by magnetic flux compression  

DOE Patents (OSTI)

A high-power-density-laser or charged-particle-beam fusion reactor system maximizes the directed kinetic energy imparted to a large mass of liquid lithium by a centrally located fusion target. A fusion target is embedded in a large mass of lithium, of sufficient radius to act as a tritium breeding blanket, and provided with ports for the access of beam energy to implode the target. The directed kinetic energy is converted directly to electricity with high efficiency by work done against a pulsed magnetic field applied exterior to the lithium. Because the system maximizes the blanket thickness per unit volume of lithium, neutron-induced radioactivities in the reaction chamber wall are several orders of magnitude less than is typical of other fusion reactor systems. 25 figs.

Lasche, G.P.

1987-02-20T23:59:59.000Z

213

Polarized neutron reflectometry in high magnetic fields  

SciTech Connect

A simple method is described to maintain the polarization of a neutron beam on its way through the large magnetic stray fields produced by a vertical field of a cryomagnet with a split-coil geometry. The two key issues are the proper shielding of the neutron spin flippers and an additional radial field component in order to guide the neutron spin through the region of the null point (i.e., point of reversal for the vertical field component). Calculations of the neutron's spin rotation as well as polarized neutron reflectometry experiments on an ErFe{sub 2}/DyFe{sub 2} multilayer show the perfect performance of the used setup. The recently commissioned cryomagnet M5 with a maximum vertical field of up to 7.2 T in asymmetric mode for polarized neutrons and 9 T in symmetric mode for unpolarized neutrons was used on the C5 spectrometer in reflectometry mode, at the NRU reactor in Chalk River, Canada.

Fritzsche, H. [National Research Council Canada, Canadian Neutron Beam Centre, Chalk River Laboratories, Chalk River, Ontario K0J 1J0 (Canada)

2005-11-15T23:59:59.000Z

214

Magnetic Fields in the Formation of Sun-Like Stars  

E-Print Network (OSTI)

We report high-angular-resolution measurements of polarized dust emission toward the low-mass protostellar system NGC 1333 IRAS 4A. We show that in this system the observed magnetic field morphology is in agreement with the standard theoretical models of the formation of Sun-like stars in magnetized molecular clouds at scales of a few hundred astronomical units; gravity has overcome magnetic support, and the magnetic field traces a clear hourglass shape. The magnetic field is substantially more important than turbulence in the evolution of the system, and the initial misalignment of the magnetic and spin axes may have been important in the formation of the binary system.

Josep M. Girart; Ramprasad Rao; Daniel P. Marrone

2006-09-06T23:59:59.000Z

215

Path Integral Confined Dirac Fermions in a Constant Magnetic Field  

E-Print Network (OSTI)

We consider Dirac fermion confined in harmonic potential and submitted to a constant magnetic field. The corresponding solutions of the energy spectrum are obtained by using the path integral techniques. For this, we begin by establishing a symmetric global projection, which provides a symmetric form for the Green function. Based on this, we show that it is possible to end up with the propagator of the harmonic oscillator for one charged particle. After some transformations, we derive the normalized wave functions and the eigenvalues in terms of different physical parameters and quantum numbers. By interchanging quantum numbers, we show that our solutions possed interesting properties. The density of current and the non-relativistic limit are analyzed where different conclusions are obtained.

Abdeldjalil Merdaci; Ahmed Jellal; Lyazid Chetouani

2014-04-17T23:59:59.000Z

216

Optical pumping magnetic resonance in high magnetic fields: Characterization of nuclear relaxation during pumping  

E-Print Network (OSTI)

Optical pumping magnetic resonance in high magnetic fields: Characterization of nuclear relaxation during pumping Matthew P. Augustine and Kurt W. Zilm Department of Chemistry, Yale University, New Haven exchange with optically pumped Rb vapor is investigated in high magnetic field. Operation in a high field

Augustine, Mathew P.

217

Two-colour QCD at non-zero temperature in the presence of a strong magnetic field  

E-Print Network (OSTI)

In this talk we report on our study of two-colour lattice QCD with N_f=4 staggered fermion degrees of freedom with equal electric charge q in a homogeneous magnetic field B at non-zero temperature T. We find indications for a non-monotonic behaviour of the critical temperature as a function of the magnetic field strength and, as a consequence, for the occurence of `inverse magnetic catalysis' within the transition region for magnetic fields in the range 0 < qB < 0.7 GeV^2.

M. Muller-Preussker; B. Petersson; A. Schreiber; E. -M. Ilgenfritz; M. Kalinowski

2014-02-01T23:59:59.000Z

218

The Generation of Nonaxisymmetric Magnetic Fields in the Giant Planets  

E-Print Network (OSTI)

by the National Science Foundation 1 #12; INTRODUCTION The dipole moments of the magnetic fields of JupiterThe Generation of Nonaxisymmetric Magnetic Fields in the Giant Planets David Moss Mathematics shells, with anisotropic alpha and magnetic diffusivity tensors which are functions of the inverse Rossby

Brandenburg, Axel

219

Sidewall containment of liquid metal with horizontal alternating magnetic fields  

DOE Patents (OSTI)

An apparatus is disclosed for confining molten metal with a horizontal alternating magnetic field. In particular, this invention employs a magnet that can produce a horizontal alternating magnetic field to confine a molten metal at the edges of parallel horizontal rollers as a solid metal sheet is cast by counter-rotation of the rollers. 19 figs.

Praeg, W.F.

1995-01-31T23:59:59.000Z

220

Efficient solar anti-neutrino production in random magnetic fields  

E-Print Network (OSTI)

We have shown that the electron anti-neutrino appearance in the framework of the spin flavor conversion mechanism is much more efficient in the case of neutrino propagation through random than regular magnetic field. This result leads to much stronger limits on the product of the neutrino transition magnetic moment and the solar magnetic field based on the recent KamLAND data. We argue that the existence of the random magnetic fields in the solar convective zone is a natural sequence of the convective zone magnetic field evolution.

O. G. Miranda; T. I. Rashba; A. I. Rez; J. W. F. Valle

2004-05-12T23:59:59.000Z

Note: This page contains sample records for the topic "magnetic field charged" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Instability of charged wormholes supported by a ghost scalar field  

SciTech Connect

In previous work, we analyzed the linear and nonlinear stability of static, spherically symmetric wormhole solutions to Einstein's field equations coupled to a massless ghost scalar field. Our analysis revealed that all these solutions are unstable with respect to linear and nonlinear spherically symmetric perturbations and showed that the perturbation causes the wormholes to either decay to a Schwarzschild black hole or undergo a rapid expansion. Here, we consider charged generalization of the previous models by adding to the gravitational and ghost scalar field an electromagnetic one. We first derive the most general static, spherically symmetric wormholes in this theory and show that they give rise to a four-parameter family of solutions. This family can be naturally divided into subcritical, critical and supercritical solutions depending on the sign of the sum of the asymptotic masses. Then, we analyze the linear stability of these solutions. We prove that all subcritical and all critical solutions possess one exponentially in time growing mode. It follows that all subcritical and critical wormholes are linearly unstable. In the supercritical case we provide numerical evidence for the existence of a similar unstable mode.

Gonzalez, J. A.; Guzman, F. S.; Sarbach, O. [Instituto de Fisica y Matematicas, Universidad Michoacana de San Nicolas de Hidalgo, Edificio C-3, Cd. Universitaria, 58040 Morelia, Michoacan (Mexico)

2009-07-15T23:59:59.000Z

222

Method of correcting eddy current magnetic fields in particle accelerator vacuum chambers  

DOE Patents (OSTI)

A method for correcting magnetic field aberrations produced by eddy currents induced in a particle accelerator vacuum chamber housing is provided wherein correction windings are attached to selected positions on the housing and the windings are energized by transformer action from secondary coils, which coils are inductively coupled to the poles of electro-magnets that are powered to confine the charged particle beam within a desired orbit as the charged particles are accelerated through the vacuum chamber by a particle-driving rf field. The power inductively coupled to the secondary coils varies as a function of variations in the power supplied by the particle-accelerating rf field to a beam of particles accelerated through the vacuum chamber, so the current in the energized correction coils is effective to cancel eddy current flux fields that would otherwise be induced in the vacuum chamber by power variations in the particle beam.

Danby, Gordon T. (Wading River, NY); Jackson, John W. (Shoreham, NY)

1991-01-01T23:59:59.000Z

223

Method of correcting eddy current magnetic fields in particle accelerator vacuum chambers  

DOE Patents (OSTI)

A method for correcting magnetic field aberrations produced by eddy currents induced in a particle accelerator vacuum chamber housing is provided wherein correction windings are attached to selected positions on the housing and the windings are energized by transformer action from secondary coils, which coils are inductively coupled to the poles of electro-magnets that are powered to confine the charged particle beam within a desired orbit as the charged particles are accelerated through the vacuum chamber by a particle-driving rf field. The power inductively coupled to the secondary coils varies as a function of variations in the power supplied by the particle-accelerating rf field to a beam of particles accelerated through the vacuum chamber, so the current in the energized correction coils is effective to cancel eddy current flux fields that would otherwise be induced in the vacuum chamber by power variations (dB/dt) in the particle beam.

Danby, G.T.; Jackson, J.W.

1990-03-19T23:59:59.000Z

224

Average East-West Inclinations of Surface Magnetic Field Lines  

Science Journals Connector (OSTI)

The east-west component of the inclination to the vertical of magnetic field lines of fields measured at the photospheric level is calculated ... and as a function of latitude. These fields represent mostly non-s...

Robert F. Howard

1994-01-01T23:59:59.000Z

225

Charged particles in higher dimensional homogeneous gravitational field: self-energy and self-force  

Science Journals Connector (OSTI)

A problem of self-energy and self-force for a charged point-like particle in a higher dimensional homogeneous gravitational field is considered. We study two cases, when a particle has the usual electric charg...

Valeri P. Frolov; Andrei Zelnikov

2014-10-01T23:59:59.000Z

226

Propagation of MHD waves in a plasma in a sheared magnetic field with straight field lines  

Science Journals Connector (OSTI)

The propagation of MHD plasma waves in a sheared magnetic field is investigated. The problem is solved using ... is inhomogeneous in one direction, and the magnetic field lines are straight. The waves are assumed...

P. N. Mager; D. Yu. Klimushkin

2002-04-01T23:59:59.000Z

227

MagLab - MagLab Dictionary: Magnetic Field (Transcript)  

NLE Websites -- All DOE Office Websites (Extended Search)

stronger magnetic field, it has even stronger effects. It can hold things to your refrigerator or, in the case of our magnets, can greatly affect how electrons move inside of...

228

Transport of Paramagnetic Liquids under Nonuniform High Magnetic Field  

Science Journals Connector (OSTI)

The recent development of numerous superconducting magnets led to remarkable increment of the investigations under high magnetic field intensities in particular in chemistry, physics and biology.1 The application of high magnetic fields clarified the existence of the magnetic force acting on any kind of nonmagnetic (paramagnetic or diamagnetic) materials. ... In the experimental conditions where the bore axis of the superconducting magnet is set vertically, the magnetic field takes a parabolic distribution in a horizontal direction with rotational symmetry, such as where B0 is the magnetic flux density in the center of the bore, ? the coefficient characterizing the parabolic shape of the magnetic field distribution, and r the coordinate of the radial axis. ... T. Dashed lines are fitted curves from eq 17. ...

Olivier Devos; Ryoichi Aogaki

2000-05-10T23:59:59.000Z

229

National High Magnetic Field Laboratory Slideshow: Making an...  

NLE Websites -- All DOE Office Websites (Extended Search)

Create your own magnetic field lines, expose the iron in your cereal, or make an electromagnet from scratch Your teachers or parents may even want to get in on the fun. Magnets...

230

Gregory S. Boebinger, National High Magnetic Field Laboratory  

NLE Websites -- All DOE Office Websites (Extended Search)

Ring Coil for Neuroimaging at 21.1 T Gregory S. Boebinger, National High Magnetic Field Laboratory DMR-Award 0654118 NMR Facility - 900MHz UWB Magnet While today s clinical...

231

National High Magnetic Field Laboratory - Science Starts Here...  

NLE Websites -- All DOE Office Websites (Extended Search)

technology. The Magnet Lab is a wonderful environment for nurturing students in high magnetic field research. The group that I worked in conducted leading-edge research in high...

232

Planetary Magnetic Field Measurements: Missions and Instrumentation  

Science Journals Connector (OSTI)

The nature and diversity of the magnetic properties of the planets have been investigated by a large number of space missions over the past 50 years. It is clear that without the magnetic field measurements th...

André Balogh

2010-05-01T23:59:59.000Z

233

Energy loss of ions by electric-field fluctuations in a magnetized plasma  

SciTech Connect

The results of a theoretical investigation of the energy loss of charged particles in a magnetized classical plasma due to the electric-field fluctuations are reported. The energy loss for a test particle is calculated through the linear-response theory. At vanishing magnetic field, the electric-field fluctuations lead to an energy gain of the charged particle for all velocities. It has been shown that in the presence of strong magnetic field, this effect occurs only at low velocities. In the case of high velocities, the test particle systematically loses its energy due to the interaction with a stochastic electric field. The net effect of the fluctuations is the systematic reduction of the total energy loss (i.e., the sum of the polarization and stochastic energy losses) at vanishing magnetic field and reduction or enhancement at strong field, depending on the velocity of the particle. It is found that the energy loss of the slow heavy ion contains an anomalous term that depends logarithmically on the projectile mass. The physical origin of this anomalous term is the coupling between the cyclotron motion of the plasma electrons and the long-wavelength, low-frequency fluctuations produced by the projectile ion. This effect may strongly enhance the stochastic energy gain of the particle.

Nersisyan, Hrachya B. [Institute of Radiophysics and Electronics, 0203 Ashtarak (Armenia); Centre of Strong Fields Physics, Yerevan State University, Alex Manoogian str. 1, 0025 Yerevan (Armenia); Deutsch, Claude [LPGP - UMR-CNRS 8578, Universite Paris XI, F-91405 Orsay (France)

2011-06-15T23:59:59.000Z

234

Charged massive particle at rest in the field of a Reissner-Nordström black hole. II. Analysis of the field lines and the electric Meissner effect  

Science Journals Connector (OSTI)

The properties of the electric field of a two-body system consisting of a Reissner-Nordström black hole and a charged massive particle at rest have recently been analyzed in the framework of first order perturbation theory following the standard approach of Regge, Wheeler, and Zerilli. In the present paper we complete this analysis by numerically constructing and discussing the lines of force of the “effective” electric field of the sole particle with the subtraction of the dominant contribution of the black hole. We also give the total field due to the black hole and the particle. As the black hole becomes extreme an effect analogous to the Meissner effect arises for the electric field, with the “effective field” lines of the point charge being expelled by the outer horizon of the black hole. This effect existing at the level of test field approximation, i.e. by neglecting the backreaction on the background metric and electromagnetic field due to the particle’s mass and charge, is here found also at the complete perturbative level. We point out analogies with similar considerations for magnetic fields by Bi?ák and Dvo?ák. We also explicitly show that the linearization of the recently obtained Belinski-Alekseev exact solution coincides with our solution in the Regge-Wheeler gauge. Our solution thus represents a bridge between the test field solution, which neglects all the feedback terms, and the exact two-body solution, which takes into account all the nonlinearity of the interaction.

D. Bini; A. Geralico; R. Ruffini

2008-03-17T23:59:59.000Z

235

Vector optical fields with polarization distributions similar to electric and magnetic field lines  

Science Journals Connector (OSTI)

We present, design and generate a new kind of vector optical fields with linear polarization distributions modeling to electric and magnetic field lines. The geometric configurations...

Pan, Yue; Li, Si-Min; Mao, Lei; Kong, Ling-Jun; Li, Yongnan; Tu, Chenghou; Wang, Pei; Wang, Hui-Tian

2013-01-01T23:59:59.000Z

236

Cosmic Acceleration and Anisotropic models with Magnetic field  

E-Print Network (OSTI)

Plane symmetric cosmological models are investigated with or without any dark energy components in the field equations. Keeping an eye on the recent observational constraints concerning the accelerating phase of expansion of the universe, the role of magnetic field is assessed. The presence of magnetic field can favour an accelerating model even if we take a linear relationship between the directional Hubble parameters.

S. K. Tripathy; K. L. Mahanta

2014-07-27T23:59:59.000Z

237

Neutron scattering in magnetic fields (*) W. C. Koehler  

E-Print Network (OSTI)

691 Neutron scattering in magnetic fields (*) W. C. Koehler Solid State Division, Oak Ridge. Abstract 2014 The use of magnetic fields in neutron scattering experimentation is reviewed briefly. Two of the scattering sample ; in the second the field acts on the neutron itself. Several examples are discussed

Boyer, Edmond

238

E-Print Network 3.0 - aligned magnetic field Sample Search Results  

NLE Websites -- All DOE Office Websites (Extended Search)

magnetic field Search Powered by Explorit Topic List Advanced Search Sample search results for: aligned magnetic field Page: << < 1 2 3 4 5 > >> 1 CHAPTER 20: MAGNETIC PROPERTIES...

239

Electrostatic and Magnetic Fields in Bilayer Graphene  

E-Print Network (OSTI)

We compute the transmission probability through rectangular potential barriers and p-n junctions in the presence of a magnetic and electric fields in bilayer graphene taking into account the full four bands of the energy spectrum. For energy E higher than the interlayer coupling $\\gamma_1 (E>\\gamma_1)$ two propagation modes are available for transport giving rise to four possible ways for transmission and reflection probabilities. However, when the energy is less then the height of the barrier the Dirac fermions exhibits transmission resonances and only one mode of propagation is available. We study the effect of the interlayer electrostatic potential $\\delta$ and the different geometry parameters of the barrier on the transmission probability.

Ahmed Jellal; Ilham Redouani; Hocine Bahlouli

2014-11-14T23:59:59.000Z

240

Influence of a dipole magnetic field on the topology of toroidal magnetic configurations around a gravitating body  

Science Journals Connector (OSTI)

The topological structure of the toroidal magnetic field, which is affected by a dipole magnetic field, is studied. It is shown, that a dipole magnetic field is able to split the initial toroidal configuration...

Vladimir A. Osherovich; Erast B. Gliner

Note: This page contains sample records for the topic "magnetic field charged" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Strongest non-destructive magnetic field: world record set at...  

NLE Websites -- All DOE Office Websites (Extended Search)

behave under the influence of very high magnetic fields, to research into the quantum behavior of phase transitions in solids. Researchers can explore extremes of low...

242

QCD at non-zero temperature and magnetic field  

E-Print Network (OSTI)

A status of lattice QCD thermodynamics, as of 2013, is summarized. Only bulk thermodynamics is considered. There is a separate section on magnetic fields.

Kalman Szabo

2014-01-16T23:59:59.000Z

243

National High Magnetic Field Laboratory: Museum of Electricity...  

NLE Websites -- All DOE Office Websites (Extended Search)

which at the receiving end flowed through an electromagnet. This created a magnetic field that caused the receivers metal key to be attracted to an underlying plate,...

244

High Pressure Research Questionnaire National High Magnetic Field...  

NLE Websites -- All DOE Office Websites (Extended Search)

Pressure Research Questionnaire National High Magnetic Field Laboratory Operated by Florida State University, University of Florida, Los Alamos National Laboratory Florida State...

245

Amplifying Magnetic Fields in High Energy Density Plasmas | U...  

Office of Science (SC) Website

Amplifying Magnetic Fields in High Energy Density Plasmas Fusion Energy Sciences (FES) FES Home About Research Facilities Science Highlights Benefits of FES Funding Opportunities...

246

High Field Magnet R&D in the USA  

E-Print Network (OSTI)

Field Magnet R&D in the USA Stephen A. Gourlay Abstract··Laboratory, Berkeley, CA 94720 USA (telephone: 510-486-7156,

Gourlay, S.A.

2011-01-01T23:59:59.000Z

247

21Mathematical Model of Magnetic Field Lines -I Magnets have a north and a south  

E-Print Network (OSTI)

21Mathematical Model of Magnetic Field Lines - I Magnets have a north and a south pole. If you make this magnet small enough so that it looks like a point, all you will see are the looping lines of force mapped out by iron fillings or by using a compass. Physicists call these patterns of lines, magnetic lines

248

Behavior of nanoparticle clouds around a magnetized microsphere under magnetic and flow fields  

E-Print Network (OSTI)

1 Behavior of nanoparticle clouds around a magnetized microsphere under magnetic and flow fields-sized magnetizable particle is introduced into a suspension of nanosized magnetic particles, the nanoparticles and allows efficient magnetic separation of nanoparticles used in bioanalysis and water purification

Paris-Sud XI, Université de

249

Mitigated-force carriage for high magnetic field environments  

SciTech Connect

A carriage for high magnetic field environments includes a first work-piece holding means for holding a first work-piece, the first work-piece holding means being disposed in an operable relationship with a work-piece processing magnet having a magnetic field strength of at least 1 Tesla. The first work-piece holding means is further disposed in operable connection with a second work-piece holding means for holding a second work-piece so that, as the first work-piece is inserted into the magnetic field, the second work-piece is simultaneously withdrawn from the magnetic field, so that an attractive magnetic force imparted on the first work-piece offsets a resistive magnetic force imparted on the second work-piece.

Ludtka, Gerard M; Ludtka, Gail M; Wilgen, John B; Murphy, Bart L

2014-05-20T23:59:59.000Z

250

Entanglement of two-qubit photon beam by magnetic field  

E-Print Network (OSTI)

We have studied the possibility of affecting the entanglement measure of 2-qubit system consisting of two photons with different fixed frequencies but with two arbitrary linear polarizations, moving in the same direction, by the help of an applied external magnetic field. The interaction between the magnetic field and the photons in our model is achieved through intermediate electrons that interact with both the photons and the magnetic field. The possibility of exact theoretical analysis of this scheme is based on known exact solutions that describe the interaction of an electron subjected to an external magnetic field (or a medium of electrons not interacting with each other) with a quantized field of two photons. We adapt these exact solutions to the case under consideration. Using explicit wave functions for the resulting electromagnetic field, we calculate the entanglement measure of the photon beam as a function of the applied magnetic field and parameters of the electron medium.

A. D. Levin; D. M. Gitman; R. C. Castro

2014-05-15T23:59:59.000Z

251

Magnetic Vortex Core Reversal by Low-Field Excitations  

NLE Websites -- All DOE Office Websites (Extended Search)

Magnetic Vortex Core Reversal by Magnetic Vortex Core Reversal by Low-Field Excitations Magnetic Vortex Core Reversal by Low-Field Excitations Print Wednesday, 28 March 2007 00:00 In micrometer-sized magnetic thin films, the magnetization typically adopts an in-plane, circular configuration known as a magnetic vortex. At the vortex core, the magnetization turns sharply out of the plane, pointing either up or down. Magnetic data storage based on this binary phenomenon is an intriguing concept, but it would require the ability to flip the vortex cores on demand. Because these structures are highly stable, very strong magnetic fields of around half a tesla (approximately one-third the field of the strongest permanent magnet) were previously thought to be necessary to accomplish this. At the ALS, a team of researchers from Germany, Belgium, and the U.S. has used time-resolved scanning transmission x-ray microscopy (STXM) to observe vortex motion and demonstrate the feasibility of using weak magnetic fields as low as 1.5 millitesla (mT) to reverse the direction of a vortex core. The observed switching mechanism, which can be understood within the framework of micromagnetic theory, gives insights into basic magnetization dynamics and their possible application to data storage technologies.

252

Electric-Field Control of Magnetism Intrinsic magnetoelectric coupling describes the microscopic interaction between magnetic and  

E-Print Network (OSTI)

Electric-Field Control of Magnetism Intrinsic magnetoelectric coupling describes the microscopic interaction between magnetic and electric polarization in a single-phase material. The control of the magnetic state of a material with an electric field is an enticing prospect for device engineering. MRSEC

Maroncelli, Mark

253

Multiple ion species plasmas with thermal ions in an oblique magnetic field  

SciTech Connect

Using a three-fluid model, the combined effects of an oblique magnetic field and finite temperature of positive ion species on the characteristics of the sheath region of multi-component plasmas are investigated numerically. It is assumed that the ion species are singly charged and have different masses. In the presence of an external magnetic field, it is shown that the density distribution of positive ion species (especially the lighter ion species) begins to fluctuate and does not decrease monotonically towards the wall. Also, it is shown that by increasing the magnetic field, the amplitude of fluctuation increases and its position moves towards the sheath edge. Moreover, it is illustrated that the presence of the magnetic field affects the sheath width and by increasing the magnetic field, the sheath width decreases. In addition, the results show that in the presence of the magnetic field, the increase of temperature of positive ion species has an infinitesimal effect on the sheath width and density distribution of positive ion species.

Hatami, M. M. [Physics Department of K N Toosi University of Technology, 15418-49611 Tehran (Iran, Islamic Republic of)] [Physics Department of K N Toosi University of Technology, 15418-49611 Tehran (Iran, Islamic Republic of)

2013-08-15T23:59:59.000Z

254

Magnetic field contribution to the last electron-photon scattering  

E-Print Network (OSTI)

When the cosmic microwave photons scatter electrons just prior to the decoupling of matter and radiation, magnetic fields do contribute to the Stokes matrix as well as to the scalar, vector and tensor components of the transport equations for the brightness perturbations. The magnetized electron-photon scattering is hereby discussed in general terms by including, for the first time, the contribution of magnetic fields with arbitrary direction and in the presence of the scalar, vector and tensor modes of the geometry. The propagation of relic vectors and relic gravitons is discussed for a varying magnetic field orientation and for different photon directions. The source terms of the transport equations in the presence of the relativistic fluctuations of the geometry are also explicitly averaged over the magnetic field orientations and the problem of a consistent account of the small-scale and large-scale magnetic field is briefly outlined.

Giovannini, Massimo

2010-01-01T23:59:59.000Z

255

SCALING LAW FOR THE IMPACT OF MAGNET FRINGE FIELDS.  

SciTech Connect

A general scaling law can be derived for the relative momentum deflection produced on a particle beam by fringe fields, to leading order. The formalism is applied to two concrete examples, for magnets having dipole and quadrupole symmetry. During recent years, the impact of magnet fringe fields is becoming increasingly important for rings of relatively small circumference but large acceptance. A few years ago, following some heuristic arguments, a scaling law was proposed [1], for the relative deflection of particles passing through a magnet fringe-field. In fact, after appropriate expansion of the magnetic fields in Cartesian coordinates, which generalizes the expansions of Steffen [2], one can show that this scaling law is true for any multipole magnet, at leading order in the transverse coefficients [3]. This paper intends to provide the scaling law to estimate the impact of fringe fields in the special cases of magnets with dipole and quadrupole symmetry.

WEI,J.; PAPAPHILIPPOU,Y.; TALMAN,R.

2000-06-30T23:59:59.000Z

256

Journal of Magnetism and Magnetic Materials 281 (2004) 272275 Effects of high magnetic field annealing on texture and  

E-Print Network (OSTI)

Journal of Magnetism and Magnetic Materials 281 (2004) 272­275 Effects of high magnetic field annealing on texture and magnetic properties of FePd D.S. Lia, *, H. Garmestania , Shi-shen Yanb , M of Materials Science and Engineering, Georgia Institute of Technology, 771 Ferst Dr. N.W., Atlanta, GA

Garmestani, Hamid

257

Measuring and shimming the magnetic field of a 4 Tesla MRI magnet  

E-Print Network (OSTI)

The Biomedical Magnetic Resonance Laboratory (BMRL) of the University of Illinois at Urbana-Champaign (UIUC) has ordered from the Texas Accelerator Center (TAC) a superconducting, self-shielded, solenoidal magnet with a maximum field of 4 Tesla...

Kyriazis, Georgios

2012-06-07T23:59:59.000Z

258

Axion decay in a strong magnetic field and radio fluxes from magnetic white dwarfs  

Science Journals Connector (OSTI)

Radio emission of isolated magnetic white dwarfs due to invisible axions decay in a strong magnetic field is estimated. It is possible to reach theoretical limits on the abundance and coupling of cosmic axions...

Yu. N. Gnedin

1990-07-01T23:59:59.000Z

259

Magnetic Vortex Core Reversal by Low-Field Excitations  

NLE Websites -- All DOE Office Websites (Extended Search)

Magnetic Vortex Core Reversal by Low-Field Excitations Print Magnetic Vortex Core Reversal by Low-Field Excitations Print In micrometer-sized magnetic thin films, the magnetization typically adopts an in-plane, circular configuration known as a magnetic vortex. At the vortex core, the magnetization turns sharply out of the plane, pointing either up or down. Magnetic data storage based on this binary phenomenon is an intriguing concept, but it would require the ability to flip the vortex cores on demand. Because these structures are highly stable, very strong magnetic fields of around half a tesla (approximately one-third the field of the strongest permanent magnet) were previously thought to be necessary to accomplish this. At the ALS, a team of researchers from Germany, Belgium, and the U.S. has used time-resolved scanning transmission x-ray microscopy (STXM) to observe vortex motion and demonstrate the feasibility of using weak magnetic fields as low as 1.5 millitesla (mT) to reverse the direction of a vortex core. The observed switching mechanism, which can be understood within the framework of micromagnetic theory, gives insights into basic magnetization dynamics and their possible application to data storage technologies.

260

Magnetic Vortex Core Reversal by Low-Field Excitations  

NLE Websites -- All DOE Office Websites (Extended Search)

Magnetic Vortex Core Reversal by Low-Field Excitations Print Magnetic Vortex Core Reversal by Low-Field Excitations Print In micrometer-sized magnetic thin films, the magnetization typically adopts an in-plane, circular configuration known as a magnetic vortex. At the vortex core, the magnetization turns sharply out of the plane, pointing either up or down. Magnetic data storage based on this binary phenomenon is an intriguing concept, but it would require the ability to flip the vortex cores on demand. Because these structures are highly stable, very strong magnetic fields of around half a tesla (approximately one-third the field of the strongest permanent magnet) were previously thought to be necessary to accomplish this. At the ALS, a team of researchers from Germany, Belgium, and the U.S. has used time-resolved scanning transmission x-ray microscopy (STXM) to observe vortex motion and demonstrate the feasibility of using weak magnetic fields as low as 1.5 millitesla (mT) to reverse the direction of a vortex core. The observed switching mechanism, which can be understood within the framework of micromagnetic theory, gives insights into basic magnetization dynamics and their possible application to data storage technologies.

Note: This page contains sample records for the topic "magnetic field charged" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Magnetic Vortex Core Reversal by Low-Field Excitations  

NLE Websites -- All DOE Office Websites (Extended Search)

Magnetic Vortex Core Reversal by Low-Field Excitations Print Magnetic Vortex Core Reversal by Low-Field Excitations Print In micrometer-sized magnetic thin films, the magnetization typically adopts an in-plane, circular configuration known as a magnetic vortex. At the vortex core, the magnetization turns sharply out of the plane, pointing either up or down. Magnetic data storage based on this binary phenomenon is an intriguing concept, but it would require the ability to flip the vortex cores on demand. Because these structures are highly stable, very strong magnetic fields of around half a tesla (approximately one-third the field of the strongest permanent magnet) were previously thought to be necessary to accomplish this. At the ALS, a team of researchers from Germany, Belgium, and the U.S. has used time-resolved scanning transmission x-ray microscopy (STXM) to observe vortex motion and demonstrate the feasibility of using weak magnetic fields as low as 1.5 millitesla (mT) to reverse the direction of a vortex core. The observed switching mechanism, which can be understood within the framework of micromagnetic theory, gives insights into basic magnetization dynamics and their possible application to data storage technologies.

262

Biological Effects of Electrical and Magnetic Fields: Is It Real?  

E-Print Network (OSTI)

The hazardous effect of electric and magnetic fields on biological systems is the subject of considerable debate. Traditional methods have failed to provide a correlation between the fields and biological effects. A model is presented that solves...

Durham, M. O.

263

A variable-field permanent-magnet dipole for accelerators  

SciTech Connect

A new concept for a variable-field permanent-magnet dipole has been developed and fabricated at Los Alamos. The application requires an extremely uniform dipole field in the magnet aperture and precision variability over a large operating range. An iron-core permanent- magnet design using a shunt that was specially shaped to vary the field in a precise and reproducible fashion with shunt position. The key to this design is in the shape of the shunt. The field as a function of shunt position is very linear from 90% of the maximum field to 20% of the minimum field. The shaped shunt also results in a small maximum magnetic force attracting the shunt to the yoke allowing a simple mechanical design. Calculated and measured results agree well for the magnet.

Kraus, R.H. Jr.; Barlow, D.B.; Meyer, R.

1992-01-01T23:59:59.000Z

264

A variable-field permanent-magnet dipole for accelerators  

SciTech Connect

A new concept for a variable-field permanent-magnet dipole has been developed and fabricated at Los Alamos. The application requires an extremely uniform dipole field in the magnet aperture and precision variability over a large operating range. An iron-core permanent- magnet design using a shunt that was specially shaped to vary the field in a precise and reproducible fashion with shunt position. The key to this design is in the shape of the shunt. The field as a function of shunt position is very linear from 90% of the maximum field to 20% of the minimum field. The shaped shunt also results in a small maximum magnetic force attracting the shunt to the yoke allowing a simple mechanical design. Calculated and measured results agree well for the magnet.

Kraus, R.H. Jr.; Barlow, D.B.; Meyer, R.

1992-09-01T23:59:59.000Z

265

Including stereoscopic information in the reconstruction of coronal magnetic fields  

E-Print Network (OSTI)

We present a method to include stereoscopic information about the three dimensional structure of flux tubes into the reconstruction of the coronal magnetic field. Due to the low plasma beta in the corona we can assume a force free magnetic field, with the current density parallel to the magnetic field lines. Here we use linear force free fields for simplicity. The method uses the line of sight magnetic field on the photosphere as observational input. The value of $\\alpha$ is determined iteratively by comparing the reconstructed magnetic field with the observed structures. The final configuration is the optimal linear force solution constrained by both the photospheric magnetogram and the observed plasma structures. As an example we apply our method to SOHO MDI/EIT data of an active region. In the future it is planned to apply the method to analyse data from the SECCHI instrument aboard the STEREO mission.

T. Wiegelmann; T. Neukirch

2008-01-23T23:59:59.000Z

266

High magnetic field processing of liquid crystalline polymers  

DOE Patents (OSTI)

A process of forming bulk articles of oriented liquid crystalline thermoset material, the material characterized as having an enhanced tensile modulus parallel to orientation of an applied magnetic field of at least 25 percent greater than said material processed in the absence of a magnetic field, by curing a liquid crystalline thermoset precursor within a high strength magnetic field of greater than about 2 Tesla, is provided, together with a resultant bulk article of a liquid crystalline thermoset material, said material processed in a high strength magnetic field whereby said material is characterized as having a tensile modulus parallel to orientation of said field of at least 25 percent greater than said material processed in the absence of a magnetic field.

Smith, M.E.; Benicewicz, B.C.; Douglas, E.P.

1998-11-24T23:59:59.000Z

267

Interaction of a Magnet and a Point Charge: Unrecognized Internal Electromagnetic Momentum  

E-Print Network (OSTI)

Whereas nonrelativistic mechanics always connects the total momentum of a system to the motion of the center of mass, relativistic systems, such as interacting electromagnetic charges, can have internal linear momentum in the absence of motion of the center of energy of the system. This internal linear momentum of the system is related to the controversial concept of "hidden momentum." We suggest that the term "hidden momentum" be abandoned. Here we use the relativistic conservation law for the center of energy to give an unambiguous definition of the "internal momentum of a system," and then we exhibit this internal momentum for the system of a magnet (modeled as a circular ring of moving charges) and a distant static point charge. The calculations provide clear illustrations of this system for three cases: a) the moving charges of the magnet are assumed to continue in their unperturbed motion, b) the moving charges of the magnet are free to accelerate but have no mutual interactions, and c) the moving charg...

Boyer, Timothy H

2014-01-01T23:59:59.000Z

268

Nuclear magnetic absorption line widths in weak magnetic fields with a Robinson oscillator  

E-Print Network (OSTI)

NUCLEAR MAGNETIC ABSORPTION LINE WIDTHS IN WEAK MAGNETIC FIELDS WITH A ROBINSON OSCILLATOR A Thesis by TIMOTHY LEE FLUGUM Subnntted to the Graduate College of Texas ARM University in partial fulfillment of the requirement for the degree... of MASTER OF SCIENCE August 19SI Major Subject: Physics NUCLEAR MAGNETIC ABSORPTION LINE WIDTHS IN WEAK MAGNETIC FIELDS WITH A ROBINSON OSCILLATOR A Thesis TIMOTHY LEE FLUGUM Approved as to style and content by: Nelson M. Duller (Chairman...

Flugum, Timothy Lee

1987-01-01T23:59:59.000Z

269

Development of magnetic separation methods of analysis: magnetic field flow fractionation  

E-Print Network (OSTI)

of MASTER OF SCIENCE August 1980 Major Subject: Chemistry DEVELOPMENT OF MAGNETIC SEPARATION METHODS OF ANALYSIS: MAGNETIC FIELD FLOW FRACTIONATION A Thesis by JAIME GARCIA-RAMIREZ Approved as to style and content by: (Chairman of Committee) 1... of MASTER OF SCIENCE August 1980 Major Subject: Chemistry DEVELOPMENT OF MAGNETIC SEPARATION METHODS OF ANALYSIS: MAGNETIC FIELD FLOW FRACTIONATION A Thesis by JAIME GARCIA-RAMIREZ Approved as to style and content by: (Chairman of Committee) 1...

Garcia-Ramirez, Jaime

2012-06-07T23:59:59.000Z

270

Singlet and triplet states of trions in ZuSe-based quantum wells probed by magnetic fields to 50 Tesla  

SciTech Connect

Singlet and triplet states of positively (X{sup +}) and negatively (X{sup -}) charged excitons in ZnSe-based quantum wells have been studied by means of photoluminescence in pulsed magnetic fields up to 50 T. The binding energy of the X{sup -} singlet state shows a monotonic increase with magnetic field with a tendency to saturation, while that of the X{sup +} slightly decreases. The triplet X{sup +} and X{sup -} states, being unbound at zero magnetic field, noticeably increase their binding energy in high magnetic fields. The experimental evidence for the interaction between the triplet and singlet states of lTions leading to their anticrossing in magnetic fields has been found.

Astakhov, G. V.; Yakovlev, D. R.; Crooker, S. A. (Scott A.); Barrick, T. (Todd); Dzyubenko, A. B.; Sander, Thomas; Kochereshko, V. P.; Ossau, W.; Faschinger, W.; Waag, A.

2002-01-01T23:59:59.000Z

271

National High Magnetic Field Laboratory - Magnets and Materials...  

NLE Websites -- All DOE Office Websites (Extended Search)

Applied Superconductivity Center, please see the center's group members page. Magnet Science & Technology Group Members Senior Personnel Bai, Hongyu Research Faculty II Phone:...

272

National High Magnetic Field Laboratory - Magnets and Materials...  

NLE Websites -- All DOE Office Websites (Extended Search)

which joined the Magnet Lab and Florida State University in 2006. The ASC advances the science and technology of superconductivity by investigating low temperature and high...

273

National High Magnetic Field Laboratory - Mission  

NLE Websites -- All DOE Office Websites (Extended Search)

research to serve an interdisciplinary scientific user community spanning materials science, condensed matter physics, magnet technology, chemistry, and biology. Provide...

274

Electron pitch angle distributions as indicators of magnetic field topology near Mars  

E-Print Network (OSTI)

magnetic field lines are associated with the Martian crustal magnetic fields and are identified. Open magnetic field lines are identified in regions of strong crustal magnetic field by the absence and that the drift motion of particles across field lines is small. In any system with two sources of magnetic field

California at Berkeley, University of

275

The role of magnetic fields in hyperon stars  

SciTech Connect

We investigate the effects of strong magnetic fields (SMF) on the properties of neutron stars that have hyperons in their composition. The matter is described by a hadronic model in which a parameterized and derivative coupling between hadrons and mesons is considered. We study the magnetic effects on the equation of state (EoS) from Landau quantization, assuming a density dependent static magnetic field that reaches 10{sup 19} G in the center of the star. The Tolman- Oppenheimer-Volkoff (TOV) equations are solved in order to show the dependence of the massradius relation and population of hyperon stars on the central magnetic field and on different hyperon coupling schemes.

Gomes, R. O.; Vasconcellos, C. A. Z. [Instituto de Física - Universidade Federal do Rio Grande do Sul, Porto Alegre, RS 91501-970 (Brazil); Dexheimer, V. [Department of Physics - Kent State University, Kent, OH 44242 (United States)

2014-05-09T23:59:59.000Z

276

Spin diffusion at finite electric and magnetic fields  

Science Journals Connector (OSTI)

Spin-transport properties at finite electric and magnetic fields are studied by using the generalized semiclassical Boltzmann equation. It is found that the spin-diffusion equation for nonequilibrium spin density and spin currents involves a number of length scales that explicitly depend on the electric and magnetic fields. The set of macroscopic equations can be used to address a broad range of the spin-transport problems in magnetic multilayers as well as in semiconductor heterostructure. A specific example of spin injection into semiconductors at arbitrary electric and magnetic fields is illustrated.

Y. Qi and S. Zhang

2003-02-27T23:59:59.000Z

277

Sidewall containment of liquid metal with vertical alternating magnetic fields  

DOE Patents (OSTI)

An apparatus is disclosed for containing molten metal using a magnet producing vertical alternating magnetic field positioned adjacent the area in which the molten metal is to be confined. This invention can be adapted particularly to the casting of metal between counter-rotating rollers with the vertical alternating magnetic field used to confine the molten metal at the edges of the rollers. Alternately, the vertical alternating magnetic field can be used as a flow regulator in casting molten metal from an opening in a channel. 9 figs.

Lari, R.J.; Praeg, W.F.; Turner, L.R.; Battles, J.E.; Hull, J.R.; Rote, D.M.

1990-12-04T23:59:59.000Z

278

Sidewall containment of liquid metal with vertical alternating magnetic fields  

DOE Patents (OSTI)

An apparatus for containing molten metal using a magnet producing vertical alternating magnetic field positioned adjacent to the area in which the molten metal is to be confined. This invention can be adapted particularly to the casting of metal between counter-rotating rollers with the vertical alternating magnetic field used to confine the molten metal at the edges of the rollers. Alternately, the vertical alternating magnetic field can be used as a flow regulator in casting molten metal from an opening in a channel. 8 figs.

Lari, R.J.; Praeg, W.F.; Turner, L.R.; Battles, J.E.; Hull, J.R.; Rote, D.M.

1988-06-17T23:59:59.000Z

279

Magnetism of a relativistic degenerate electron gas in a strong magnetic field  

SciTech Connect

The magnetization and magnetic susceptibility of a degenerate electron gas in a strong magnetic field in which electrons are located on the ground Landau level and the electron gas has the properties of a nonlinear paramagnet have been calculated. The paradoxical properties of the electron gas under these conditions-a decrease in the magnetization with the field and an increase in the magnetization with the temperature-have been revealed. It has been shown that matter under the corresponding conditions of neutron stars is a paramagnet with a magnetic susceptibility of {chi} {approx} 0.001.

Skobelev, V. V., E-mail: v.skobelev@inbox.ru [Moscow State Industrial University (Russian Federation)

2012-09-15T23:59:59.000Z

280

Field-line transport in stochastic magnetic fields: Percolation, Lévy flights, and non-Gaussian dynamics  

Science Journals Connector (OSTI)

The transport of magnetic field lines is studied numerically in the case where strong three-dimensional magnetic fluctuations are superimposed to a uniform average magnetic field. The magnetic percolation of field lines between magnetic islands is found, as well as a non-Gaussian regime where the field lines exhibit Lévy random walks, changing from Lévy flights to trapped motion. Anomalous diffusion laws ??xi2??s? with ?>1 and ?<1 are found for low fluctuation levels, while normal diffusion and Gaussian random walks are recovered for sufficiently high fluctuation levels.

G. Zimbardo and P. Veltri

1995-02-01T23:59:59.000Z

Note: This page contains sample records for the topic "magnetic field charged" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Model of a magnetic field in poloidal divertor tokamaks affected by resonant magnetic perturbations  

SciTech Connect

A generic analytical model for the description of magnetic field lines in poloidal divertor tokamaks in the presence of external resonant magnetic perturbations is proposed. It is based on the Hamiltonian description of magnetic field lines in tokamaks. The safety factor and the spectra of magnetic perturbations are chosen by the requirement to satisfy their generic behavior near the magnetic separatrix and at the magnetic axis. The field line equations of the model are integrated using symplectic efficient mappings of field lines. The analytical formulas for the quasilinear diffusion and convection coefficients of field lines are obtained. The latter describes the outwardly directed transport of field lines at the plasma edge. It was shown that they are in a good agreement with the corresponding numerically calculated coefficients.

Abdullaev, S. S. [Forschungszentrum Juelich GmbH, Institute of Energy Research IEF-4: Plasma Physics, Association EURATOM-FZJ, Partner in the Trilateral Euregio Cluster, 52425 Juelich (Germany)

2009-03-15T23:59:59.000Z

282

2.6 ELECTRIC AND MAGNETIC FIELDS Introduction  

E-Print Network (OSTI)

325 §2.6 ELECTRIC AND MAGNETIC FIELDS Introduction In electromagnetic theory the mks system MKS units Replacement symbol GAUSSIAN units # E (Electric field) volt/m # E statvolt/cm # B (Magnetic potential) weber/m # A c gauss­cm V (Electric potential) volt V statvolt # (Dielectric constant) # 4# µ

California at Santa Cruz, University of

283

Studies of Cryogenic Electron Plasmas in Magnetic Mirror Fields  

E-Print Network (OSTI)

Studies of Cryogenic Electron Plasmas in Magnetic Mirror Fields by Ramesh Gopalan A.B. (University: Chair Date Date Date University of California at Berkeley 1998 #12;Studies of Cryogenic Electron Plasmas in Magnetic Mirror Fields Copyright 1998 by Ramesh Gopalan #12;1 Abstract Studies of Cryogenic Electron

Fajans, Joel

284

Breaking van der Waals Molecules with Magnetic Fields  

Science Journals Connector (OSTI)

It is demonstrated that weakly bound van der Waals complexes can dissociate in a magnetic field through coupling between the Zeeman levels. The Zeeman predissociation process is shown to be efficient and it can be controlled by external magnetic fields.

R. V. Krems

2004-06-28T23:59:59.000Z

285

Phase transitions in quark matter under strong magnetic fields  

SciTech Connect

In this work we use de SU(2) Nambu-Jona-Lasinio model to study the chiral transition at finite temperature, chemical potential and magnetic field. We show how the magnetic field affects the location of the critical end-point in the phase diagram, the constituent quark masses and the spinodal lines concerning the first order transition.

Garcia, Andre F.; Pinto, Marcus B. [Physics Department, Universidade Federal de Santa Catarina (Brazil)

2013-03-25T23:59:59.000Z

286

TWO FREEDERICKSZ TRANSITIONS IN CROSSED ELECTRIC AND MAGNETIC FIELDS  

E-Print Network (OSTI)

965 TWO FREEDERICKSZ TRANSITIONS IN CROSSED ELECTRIC AND MAGNETIC FIELDS H. J. DEULING-p-dibu- tylazoxybenzène. Abstract. 2014 A planar nematic slab shows a Freedericksz transition in a perpendicular electric by external electric or magnetic fields. The resulting distortion is governed by a balance of stabilizing

Boyer, Edmond

287

THE VIBRATION OF A CONDUCTING WIRE IN A MAGNETIC FIELD  

Science Journals Connector (OSTI)

......1963 research-article Articles THE VIBRATION OF A CONDUCTING WIRE IN A MAGNETIC FIELD...Polytechnic Institute of Brooklyn. The vibration of a perfectly flexible, stretched...inpedance of the wire is discuassed. THE VIBRATION OF A CONDUCTING WIRE IN A MAGNETIC FIELD......

M.A. LEIBOWITZ; R.C. ACKERBERG

1963-11-01T23:59:59.000Z

288

On the Magnetic Field of Pulsars with Realistic Neutron Stars Configurations  

E-Print Network (OSTI)

We have recently developed a neutron star model fulfilling global and not local charge neutrality, both in the static and in the uniformly rotating cases. The model is described by the coupled Einstein-Maxwell-Thomas- Fermi (EMTF) equations, in which all fundamental interactions are accounted for in the framework of general relativity and relativistic mean field theory. Uniform rotation is introduced following the Hartle's formalism. We show that the use of realistic parameters of rotating neutron stars obtained from numerical integration of the self-consistent axisymmetric general relativistic equations of equilibrium leads to values of the magnetic field and radiation efficiency of pulsars very different from estimates based on fiducial parameters assuming a neutron star mass, M = 1.4 Msun, radius R = 10 km, and moment of inertia, I = 10^45 g cm^2. In addition, we compare and contrast the magnetic field inferred from the traditional Newtonian rotating magnetic dipole model with respect to the one obtained f...

Belvedere, Riccardo; Ruffini, Remo

2014-01-01T23:59:59.000Z

289

PROTOSTELLAR DISK FORMATION ENABLED BY WEAK, MISALIGNED MAGNETIC FIELDS  

SciTech Connect

The gas from which stars form is magnetized, and strong magnetic fields can efficiently transport angular momentum. Most theoretical models of this phenomenon find that it should prevent formation of large (>100 AU), rotationally supported disks around most protostars, even when non-ideal magnetohydrodynamic (MHD) effects that allow the field and gas to decouple are taken into account. Using recent observations of magnetic field strengths and orientations in protostellar cores, we show that this conclusion is incorrect. The distribution of magnetic field strengths is very broad, and alignments between fields and angular momentum vectors within protostellar cores are essentially random. By combining the field strength and misalignment data with MHD simulations showing that disk formation is expected for both weak and misaligned fields, we show that these observations imply that we should expect disk fractions of {approx}10%-50% even when protostars are still deeply embedded in their parent cores, and even if the gas is governed by ideal MHD.

Krumholz, Mark R. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Crutcher, Richard M. [Department of Astronomy, University of Illinois at Urbana-Champaign, 1002 W Green Street, Urbana, IL 61801 (United States); Hull, Charles L. H., E-mail: mkrumhol@ucsc.edu [Astronomy Department and Radio Astronomy Laboratory, University of California, Berkeley, CA 94720-3411 (United States)

2013-04-10T23:59:59.000Z

290

Plasma-satellite interaction driven magnetic field perturbations  

SciTech Connect

We report the first fully kinetic quantitative estimate of magnetic field perturbations caused by the interaction of a spacecraft with space environment. Such perturbations could affect measurements of geophysical magnetic fields made with very sensitive magnetometers on-board satellites. Our approach is illustrated with a calculation of perturbed magnetic fields near the recently launched Swarm satellites. In this case, magnetic field perturbations do not exceed 20 pT, and they are below the sensitivity threshold of the on-board magnetometers. Anticipating future missions in which satellites and instruments would be subject to more intense solar UV radiation, however, it appears that magnetic field perturbations associated with satellite interaction with space environment, might approach or exceed instruments' sensitivity thresholds.

Saeed-ur-Rehman, E-mail: surehman@ualberta.ca [Department of Physics, University of Alberta, Edmonton, Alberta T6G 2E1 (Canada); Theoretical Physics Division, PINSTECH, Nilore Islamabad 44000 (Pakistan); Marchand, Richard, E-mail: Richard.Marchand@ualberta.ca [Department of Physics, University of Alberta, Edmonton, Alberta T6G 2E1 (Canada)

2014-09-15T23:59:59.000Z

291

GRB Phenomenology, Shock Dynamo, and the First Magnetic Fields  

E-Print Network (OSTI)

A relativistic collisionless shock propagating into an unmagnetized medium leaves behind a strong large-scale magnetic field. This seems to follow from two assumptions: (i) GRB afterglows are explained by synchrotron emission of a relativistic shock, (ii) magnetic field can't exist on microscopic scales only, it would decay by phase space mixing. Assumption (i) is generally accepted because of an apparent success of the shock synchrotron phenomenological model of GRB afterglow. Assumption (ii) is confirmed in this work by a low-dimensional numerical simulation. One may hypothesize that relativistic shock velocities are not essential for the magnetic field generation, and that all collisionless shocks propagating into an unmagnetized medium generate strong large-scale magnetic fields. If this hypothesis is true, the first cosmical magnetic fields could have been generated in shocks of the first virialized objects.

Andrei Gruzinov

2001-07-05T23:59:59.000Z

292

Mass separation of a multicomponent plasma flow in a curvilinear magnetic field  

SciTech Connect

The motion of a metal plasma flow of a vacuum-arc discharge in a transportation plasma-optical system with a curvilinear magnetic field is studied experimentally and numerically. The flow position at the output of the system is shown to depend on the cathode material, which determines the mass-to-charge ratio of plasma ions. As a result, the flow with a greater ion mass-to-charge ratio moves along a trajectory with a larger radius. A similar effect is observed in the case of a multicomponent plasma flow generated by a composite cathode. The results of two-fluid MHD simulations of a plasma flow propagating in a curvilinear magnetic field agree qualitatively with the experimental data.

Papernyi, V. L.; Krasov, V. I. [Irkutsk State University (Russian Federation)

2011-11-15T23:59:59.000Z

293

Generation of a spin-polarized electron beam by multipoles magnetic fields  

E-Print Network (OSTI)

The propagation of an electron beam in the presence of transverse magnetic fields possessing integer topological charges is presented. The spin--magnetic interaction introduces a nonuniform spin precession of the electrons that gains a space-variant geometrical phase in the transverse plane proportional to the field's topological charge, whose handedness depends on the input electron's spin state. A combination of our proposed device with an electron orbital angular momentum sorter can be utilized as a spin-filter of electron beams in a mid-energy range. We examine these two different configurations of a partial spin-filter generator numerically. The results of these analysis could prove useful in the design of improved electron microscope.

Ebrahim Karimi; Vincenzo Grillo; Robert W. Boyd; Enrico Santamato

2013-06-10T23:59:59.000Z

294

1982 IEEE TRANSACTIONS ON MAGNETICS, VOL. 44, NO. 8, AUGUST 2008 Analytical Calculation of the Magnetic Field Created  

E-Print Network (OSTI)

]. It is noticeable that in some applications, such as permanent-magnet motors [18] or magnetic couplings [19], tiles of the Magnetic Field Created by Permanent-Magnet Rings R. Ravaud, G. Lemarquand, V. Lemarquand, and C. Depollier analytical formulations, based on a coulombian approach, of the magnetic field created by permanent-magnet

Paris-Sud XI, Université de

295

Magnetic Fields in High-Mass Infrared Dark Clouds  

E-Print Network (OSTI)

High-mass Stars are cosmic engines known to dominate the energetics in the Milky Way and other galaxies. However, their formation is still not well understood. Massive, cold, dense clouds, often appearing as Infrared Dark Clouds (IRDCs), are the nurseries of massive stars. No measurements of magnetic fields in IRDCs in a state prior to the onset of high-mass star formation (HMSF) have previously been available, and prevailing HMSF theories do not consider strong magnetic fields. Here, we report observations of magnetic fields in two of the most massive IRDCs in the Milky Way. We show that IRDCs G11.11-0.12 and G0.253+0.016 are strongly magnetized and that the strong magnetic field is as important as turbulence and gravity for HMSF. The main dense filament in G11.11-0.12 is perpendicular to the magnetic field, while the lower density filament merging onto the main filament is parallel to the magnetic field. The implied magnetic field is strong enough to suppress fragmentation sufficiently to allow HMSF. Other ...

Pillai, Thushara; Tan, Jonathan; Goldsmith, Paul; Carey, Sean; Menten, Karl

2014-01-01T23:59:59.000Z

296

Capillary instability of the cylindrical interface between ferrofluids in a magnetic field with circular field lines  

Science Journals Connector (OSTI)

Capillary breakup of a viscous magnetic fluid layer subjected to a gradient magnetic field under hydroweightlessness is studied within the linear theory. The cylinder surface of a current-carrying conductor se...

V. M. Korovin

2001-12-01T23:59:59.000Z

297

Analysis of magnetic fields produced far from electric power lines  

SciTech Connect

In this paper, the authors develop a simple and general method for analyzing the magnetic fields produced by power lines at far distances, that is, at distances large in comparison to the spacing between the line's phase conductors. Magnetic fields produced far from conventional power lines have remarkably simple properties. The authors present formulae for the fields produced by various conventional and unconventional power line configurations; included are line designs characterized by reduced magnetic-field levels. Errors in the formulae are less than [plus minus]10% at the edge of a typical transmission right-of-way.

Kaune, W.T. (Enertech Consultants Campbell, CA (United States)); Zaffanella, L.E. (High Voltage Transmission Research Center, Lenox, MA (United States))

1992-10-01T23:59:59.000Z

298

Magnetic Field Production during Preheating at the Electroweak Scale  

Science Journals Connector (OSTI)

We study the generation of magnetic fields during preheating within a scenario of hybrid inflation at the electroweak scale. We find that the nonperturbative and strongly out-of-equilibrium process of generation of magnetic fields with a nontrivial helicity occurs along the lines predicted by Vachaspati many years ago. The magnitude (?B/?EW?10-2) and correlation length of these helical magnetic fields grow linearly with time during preheating and are consistent with the possibility that these seeds gave rise to the microgauss fields observed today in galaxies and clusters of galaxies.

Andrés Díaz-Gil; Juan García-Bellido; Margarita García Pérez; Antonio González-Arroyo

2008-06-16T23:59:59.000Z

299

Particle Dynamics around Riessner-Nordstr\\"om Black Hole with Magnetic Field  

E-Print Network (OSTI)

We investigate the dynamics of a neutral and a charged particle around the Reissner-Nordstr\\"om (RN) black hole immersed in magnetic field. We are interested to explore the conditions under which the moving charged particle can escape to infinity after collision with another neutral particle or a photon in the vicinity of the BH. We have calculated the expressions of the escape velocity. Further we have studied that how does the presence of magnetic field in the vicinity of BH, effect the motion of the orbiting particle. There are more than one stable regions if we consider the magnetic field in the accretion disk of BH so the stability of ISCO increases in the presence of magnetic field. We have also discussed the Lyapunov exponent in detail. Time-like geodesics of the moving particle are also studied. It is observed that the particle goes closer to the extremal RN-BH as compared to the case when it is moving around RN-BH.

Majeed, Bushra; Jamil, Mubasher

2014-01-01T23:59:59.000Z

300

Particle Dynamics around Riessner-Nordström Black Hole with Magnetic Field  

E-Print Network (OSTI)

We investigate the dynamics of a neutral and a charged particle around the Reissner-Nordstr\\"om (RN) black hole immersed in magnetic field. We are interested to explore the conditions under which the moving charged particle can escape to infinity after collision with another neutral particle or a photon in the vicinity of the BH. We have calculated the expressions of the escape velocity. Further we have studied that how does the presence of magnetic field in the vicinity of BH, effect the motion of the orbiting particle. There are more than one stable regions if we consider the magnetic field in the accretion disk of BH so the stability of ISCO increases in the presence of magnetic field. We have also discussed the Lyapunov exponent in detail. Time-like geodesics of the moving particle are also studied. It is observed that the particle goes closer to the extremal RN-BH as compared to the case when it is moving around RN-BH.

Bushra Majeed; Saqib Hussain; Mubasher Jamil

2014-11-18T23:59:59.000Z

Note: This page contains sample records for the topic "magnetic field charged" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Massive charged scalar field in the Kerr-Newman background II: Hawking radiation  

E-Print Network (OSTI)

We perform accurate calculations of the energy-, momentum-, and charge-emission rates of a charged scalar field in the background of the Kerr-Newman black hole at the range of parameters for which the effect is not negligibly small and, at the same time, the semiclassical regime is, at least marginally, valid. For black holes with charge below or not much higher than the charge accretion limit $Q \\sim \\mu M/e$ (where $e$ and $\\mu$ are the electron's mass and charge), the time between the consequent emitting of two charged particles is very large. For primordial black holes the transition between the increasing and decreasing of the ratio $Q/M$ occurs around the charge accretion limit. The rotation increases the intensity of radiation up to three orders, while the effect of the field's mass strongly suppresses the radiation.

R. A. Konoplya; A. Zhidenko

2014-04-03T23:59:59.000Z

302

Recovery of the global magnetic field configuration of 78 Virginis from Stokes IQUV line profiles  

E-Print Network (OSTI)

The surface magnetic field configuration of the Ap star HD 118022 (78 Vir) has been reconstructed in the framework of the magnetic charge distribution (MCD) method from the analysis of Stokes $IQUV$ spectra obtained using the MuSiCoS spectropolarimeter at Pic du Midi Observatory. Magnetically-sensitive Fe~{\\sc ii} lines were primarily employed in the analysis, supposing that iron is evenly distributed over the stellar surface. We show that the Stokes $IQUV$ profile shapes and variations of 78 Vir can be approximately fit assuming a global magnetic field configuration described by a slightly decentered, inclined magnetic dipole of polar surface intensity approximately 3.3~kG. The derived inclinations of the stellar rotational axis to the line of sight $i=24\\pm 5\\degr$ as well as to the magnetic dipole axis $\\beta=124\\pm5\\degr$ are in good agreement with previous estimations by other authors, whereas the sky-projected position angle\\thanks{$\\Omega$ increases clockwise from the axis to the North Celestial Pole and relates to the azimuth angle $\\Theta$ specified by Landolfi at al.~(\\cite{Landolfi+93}) as $\\Omega=360\\degr-\\Theta$.} of the stellar rotation axis $\\Omega\\sim110\\degr$ is reported here for the first time. In addition, several lines of Cr~{\\sc ii} and Ti~{\\sc ii} were studied, yielding evidence for non-uniform surface distributions of these elements, and magnetic field results similar to those derived from Fe.

V. R. Khalack; G. A. Wade

2006-01-30T23:59:59.000Z

303

Electricity and Magnetism Review Notes by L. Qian1  

E-Print Network (OSTI)

) --------------------------------------------------- ------------------------------------------------- Electric Field Lines: Magnetic Field Lines: - Start from positive charges or - External field lines start) --------------------------------------------------- ------------------------------------------------- Electric Field: Magnetic Field: Symbol: E r Symbol: B r Unit: V/m = N/C Unit: T = Ns /(Cm) [T: Tesla] - Electric field due to a static charge q - Magnetic field due to a current element sdi r r r q E ^ 4 1 2 0 r

Qian, Li

304

Mean Field Theory of Josephson Junction Arrays with Charge Frustration  

E-Print Network (OSTI)

Using the path integral approach, we provide an explicit derivation of the equation for the phase boundary for quantum Josephson junction arrays with offset charges and non-diagonal capacitance matrix. For the model with nearest neighbor capacitance matrix and uniform offset charge $q/2e=1/2$, we determine, in the low critical temperature expansion, the most relevant contributions to the equation for the phase boundary. We explicitly construct the charge distributions on the lattice corresponding to the lowest energies. We find a reentrant behavior even with a short ranged interaction. A merit of the path integral approach is that it allows to provide an elegant derivation of the Ginzburg-Landau free energy for a general model with charge frustration and non-diagonal capacitance matrix. The partition function factorizes as a product of a topological term, depending only on a set of integers, and a non-topological one, which is explicitly evaluated.

G. Grignani; A. Mattoni; P. Sodano; A. Trombettoni

1999-02-12T23:59:59.000Z

305

Development for Hardware for Programming of Spatial Magnetic Field Distributions in Nuclear Magnetic Resonance and Magnetic Resonance Imaging  

E-Print Network (OSTI)

The proposal of a project aimed on a design of hardware for programming 3D Magnetic Field shapes over sample volume in NMR and MRI is described.

Vladimir Korostelev

2012-01-13T23:59:59.000Z

306

Relaxing the bounds on primordial magnetic seed fields  

Science Journals Connector (OSTI)

We point out that the lower bound on the primordial magnetic field required to seed the galactic dynamo is significantly relaxed in an open universe or in a universe with a positive cosmological constant. In such universes, the increased age of galaxies gives a dynamo mechanism more time to amplify a small initial field. It is shown that, for reasonable cosmological parameters, primordial seed fields of strength 10-30 G or less at the time of galaxy formation could explain observed galactic magnetic fields. As a consequence, mechanisms of primordial magnetic seed-field generation that have previously been ruled out could well be viable. We also comment on the implications of the observation of micro-Gauss magnetic fields in galaxies at high redshift.

Anne-Christine Davis; Matthew Lilley; Ola Törnkvist

1999-06-23T23:59:59.000Z

307

Magnetic properties changes of MnAs thin films irradiated with highly charged ions  

E-Print Network (OSTI)

transition from hexagonal ( phase) to orthorhombic ( phase, MnP type) is accompanied by a ferromagnetic transition that leads to the - phase coexistence over a large range of temperatures (10­45 C [9Magnetic properties changes of MnAs thin films irradiated with highly charged ions M. Trassinellia

308

National High Magnetic Field Laboratory: Magnetic Thin Films  

NLE Websites -- All DOE Office Websites (Extended Search)

recorded work with magnetic thin films took place in the 1880s and was carried out by German physicist August Kundt. Well known for his research on sound and optics, Kundts...

309

National High Magnetic Field Laboratory - Basic Science  

NLE Websites -- All DOE Office Websites (Extended Search)

fruits of Faraday's discovery of electromagnetic induction. A more recent example is magnetic resonance imaging (MRI), which originated in basic research that started in the...

310

Superconducting trapped-field magnets: Temperature and field distributions during pulsed-field activation  

E-Print Network (OSTI)

progress in fabrication of large-sized high- temperature superconductors with high critical current den We calculate the temperature and magnetic field distributions in a bulk superconductor during leads to a strong temperature rise in superconductor during the activation pro- cess. There have already

Johansen, Tom Henning

311

Observation of field-reversed configurations with spheromak magnetic field profiles  

Science Journals Connector (OSTI)

We report the first observation of field-reversed configurations with nearly force-free magnetic fields in the central region of the compact toroid. The field profiles and flux ratios suggest that some form of relaxation phenomenon is occurring in this high-? kinetic regime. The magnetic helicity of the translating plasmas arises from axial asymmetry, possibly through end-shorting Alfvén waves.

M. Tuszewski and B. L. Wright

1989-11-13T23:59:59.000Z

312

Los Alamos achieves world-record pulsed magnetic field  

NLE Websites -- All DOE Office Websites (Extended Search)

Los Alamos achieves world-record pulsed magnetic field Los Alamos achieves world-record pulsed magnetic field Los Alamos achieves world-record pulsed magnetic field Researchers have set a new world record for the strongest magnetic field produced by a nondestructive magnet. August 23, 2011 Los Alamos National Laboratory sits on top of a once-remote mesa in northern New Mexico with the Jemez mountains as a backdrop to research and innovation covering multi-disciplines from bioscience, sustainable energy sources, to plasma physics and new materials. Los Alamos National Laboratory sits on top of a once-remote mesa in northern New Mexico with the Jemez mountains as a backdrop to research and innovation covering multi-disciplines from bioscience, sustainable energy sources, to plasma physics and new materials.

313

Analysis of Reccurent Patterns in Toroidal Magnetic Fields  

SciTech Connect

In the development of magnetic confinement fusion which will be a future source for low cost power, physicists must be able to analyze the magnetic field that confines the burning plasma. While the magnetic field can be described as a series of vectors, traditional techniques for analyzing the field s topology can not be used because of its homoclinic nature. In this paper we describe a technique developed as a collaboration between physicists and computer scientists that determines the topology of a toroidal magnetic field using fieldlines with near minimal lengths. More specifically, we analyze the Poincare map of the sampled fieldlines in a Poincare section including identifying critical points and other topological features of interest to physicists. The technique has been deployed into an interactive parallel visualization tool which physicists are using to gain new insight into simulations of magnetically confined buring plasmas.

Sanderson, Allen [University of Utah; Pugmire, Dave [ORNL

2010-11-01T23:59:59.000Z

314

National High Magnetic Field Laboratory - DC Field Program: Portable...  

NLE Websites -- All DOE Office Websites (Extended Search)

Portable Dilution Refrigerator Portable Dilution Refrigerator Portable Dilution Refrigerator installed in the 45T hybrid magnet. A portable dilution refrigerator (PDF) is available...

315

Directly Mapping Magnetic Field Effects of Neuronal Activity by Magnetic Resonance  

E-Print Network (OSTI)

Directly Mapping Magnetic Field Effects of Neuronal Activity by Magnetic Resonance Imaging Jinhu Xiong,* Peter T. Fox, and Jia-Hong Gao Research Imaging Center, University of Texas Health Science Center at San Antonio, San Antonio, Texas Abstract: Magnetic resonance imaging (MRI) of brain functional

Gabrieli, John

316

Bose Glass of Quasiparticles in Doped Quantum Magnet Gregory S. Boebinger, National High Magnetic Field Laboratory  

E-Print Network (OSTI)

Bose Glass of Quasiparticles in Doped Quantum Magnet Gregory S. Boebinger, National High Magnetic. This BEC can localize in the presence of disorder caused by Br- doping to form a Bose Glass. The BEC-Bose Glass (BEC-BG) transition can be carefully controlled by magnetic field, allowing us to sensitively

Weston, Ken

317

Magnetic Helicity and the Relaxation of Fossil Fields  

E-Print Network (OSTI)

In the absence of an active dynamo, purely poloidal magnetic field configurations are unstable to large-scale dynamical perturbations, and decay via reconnection on an Alfvenic timescale. Nevertheless, a number of classes of dynamo-free stars do exhibit significant, long-lived, surface magnetic fields. Numerical simulations suggest that the large-scale poloidal field in these systems is stabilized by a toroidal component of the field in the stellar interior. Using the principle of conservation of total helicity, we develop a variational principle for computing the structure of the magnetic field inside a conducting sphere surrounded by an insulating vacuum. We show that, for a fixed total helicity, the minimum energy state corresponds to a force-free configuration. We find a simple class of axisymmetric solutions, parametrized by angular and radial quantum numbers. However, these solutions have a discontinuity in the toroidal magnetic field at the stellar surface which will exert a toroidal stress on the surface of the star. We then describe two other classes of solutions, the standard spheromak solutions and ones with fixed surface magnetic fields, the latter being relevant for neutron stars with rigid crusts. We discuss the implications of our results for the structure of neutron star magnetic fields, the decay of fields, and the origin of variability and outbursts in magnetars.

Avery E. Broderick; Ramesh Narayan

2007-02-05T23:59:59.000Z

318

On the magnetic fields in voids  

Science Journals Connector (OSTI)

......estimate the transport of magnetic energy by cosmic rays (CR) from the...small fraction of the magnetic energy contained in the void galaxies...809. Longair M. S. High Energy Astrophysics (2010) Cambridge...Pogorelov N. V., Font J. A., Audit E., Zank G. P., eds......

A. M. Beck; M. Hanasz; H. Lesch; R.-S. Remus; F. A. Stasyszyn

2013-01-01T23:59:59.000Z

319

Abstract--Temperature, current density and magnetic field distributions in YBCO bulk superconductor during a pulsed-field  

E-Print Network (OSTI)

-- bulk YBaCuO, stored magnetic energy, thermal coupling, magnetization, modelling. I. INTRODUCTION HE as cryo-permanent magnets [1], [2]. To magnetize the HTS, pulsed field magnetization (PFM) process1 Abstract-- Temperature, current density and magnetic field distributions in YBCO bulk

Paris-Sud XI, Université de

320

Geometric properties of magnetic field lines on toroidal magnetic surfaces in the context of plasma equilibrium  

SciTech Connect

An analysis of plasma equilibrium in a magnetic confinement system includes studies of how the shape of the magnetic surfaces is distorted with varying magnitude and profile of the plasma pressure. Such studies allow one, in particular, to determine the maximum {beta} value consistent with equilibrium, {beta}{sub eq}, i.e., the maximum plasma pressure above which the equilibrium in a confinement system under analysis is impossible. Since the magnetic field lines form magnetic surfaces, their global relationship with equilibrium is obvious. Here, special attention is paid to a local relationship between equilibrium and geometric properties of the magnetic field lines.

Skovoroda, A. A. [Russian Research Centre Kurchatov Institute, Nuclear Fusion Institute (Russian Federation)

2007-08-15T23:59:59.000Z

Note: This page contains sample records for the topic "magnetic field charged" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

CALCULATION OF PULSED KICKER MAGNETIC FIELD ATTENUATION INSIDE BEAM CHAMBERS  

NLE Websites -- All DOE Office Websites (Extended Search)

CALCULATION OF PULSED KICKER MAGNETIC FIELD ATTENUATION CALCULATION OF PULSED KICKER MAGNETIC FIELD ATTENUATION INSIDE BEAM CHAMBERS S. H. Kim January 8, 2001 1. Introduction and Summary The ceramic beam chambers in the sections of the kicker magnets for the beam injection and extraction in the Advanced Photon Source (APS) are made of alumina. The inner surface of the ceramic chamber is coated with a conductive paste. The choice of coating thickness is intended to reduce the shielding of the pulsed kicker magnetic field while containing the electromagnetic fields due to the beam bunches inside the chamber, and minimize the Ohmic heating due to the fields on the chamber [1]. The thin coating generally does not give a uniform surface resistivity for typical dimensions of the ceramic chambers in use. The chamber cross section is a circular or

322

Universality of critical magnetic field in holographic superconductor  

E-Print Network (OSTI)

Holographic superconductors with constant external magnetic field have been investigated by analytical matching method. It has been shown that the critical temperature and critical magnetic field can be calculated in non-zero temperature. Meissner effect has been observed in such superconductors. The relationship between normal entropy mode and superconductor with Bekenstein upper bound has been studied. Universal relation between black hole mass $ M$ and critical magnetic field $H_c$ has been proposed as $\\frac{H_c}{M^{2/3}}\\leq 0.60045$.

Davood Momeni; Ratbay Myrzakulov

2014-01-13T23:59:59.000Z

323

Heat pipes for use in a magnetic field  

DOE Patents (OSTI)

A heat pipe configuration for use in a magnetic field environment of a fusion reactor is disclosed. Heat pipes for operation in a magnetic field when liquid metal working fluids are used are optimized by flattening of the heat pipes having an unobstructed annulus which significantly reduces the adverse side region effect of the prior known cylindrically configured heat pipes. The flattened heat pipes operating in a magnetic field can remove 2--3 times the heat as a cylindrical heat pipe of the same cross sectional area. 4 figs.

Werner, R.W.; Hoffman, M.A.

1983-07-19T23:59:59.000Z

324

National High Magnetic Field Laboratory - Online Tour  

NLE Websites -- All DOE Office Websites (Extended Search)

Audio Slideshows Arrow Online Tour Welcome to the Mag Lab's online tour. As we show you around the Florida State University branch of the world's biggest magnet lab, our scientists...

325

Heat pulse propagation in chaotic 3-dimensional magnetic fields  

E-Print Network (OSTI)

Heat pulse propagation in $3$-D chaotic magnetic fields is studied by solving the parallel heat transport equation using a Lagrangian-Green's function (LG) method. The LG method provides an efficient and accurate technique that circumvents limitations of finite elements and finite difference methods. The main two problems addressed are: (i) The dependence of the radial transport on the magnetic field stochasticity (controlled by the amplitude of the perturbation, $\\epsilon$); and (ii) The role of reversed shear configurations on pulse propagation. In all the cases considered there are no magnetic flux surfaces. However, radial transport is observed to depend strongly on $\\epsilon$ due to the presence of high-order magnetic islands and Cantori that act as quasi-transport barriers that preclude the radial penetration of heat pulses within physically relevant time scale. The dependence of the magnetic field connection length, $\\ell_B$, on $\\epsilon$ is studied in detail. The decay rate of the temperature maximum...

del-Castillo-Negrete, D

2014-01-01T23:59:59.000Z

326

Charged massive particle at rest in the field of a Reissner-Nordström black hole. II. Analysis of the field lines and the electric Meissner effect  

E-Print Network (OSTI)

The properties of the electric field of a two-body system consisting of a Reissner-Nordstr\\"om black hole and a charged massive particle at rest have recently been analyzed in the framework of first order perturbation theory following the standard approach of Regge, Wheeler and Zerilli. In the present paper we complete this analysis by numerically constructing and discussing the lines of force of the "effective" electric field of the sole particle with the subtraction of the dominant contribution of the black hole. We also give the total field due to the black hole and the particle. As the black hole becomes extreme an effect analogous to the Meissner effect arises for the electric field, with the "effective field" lines of the point charge being expelled by the outer horizon of the black hole. This effect existing at the level of test field approximation, i.e. by neglecting the backreaction on the background metric and electromagnetic field due to the particle's mass and charge, is here found also at the complete perturbative level. We point out analogies with similar considerations for magnetic fields by Bi{\\v c}\\'ak and Dvo{\\v r}\\'ak. We also explicitly show that the linearization of the recently obtained Belinski-Alekseev exact solution coincides with our solution in the Regge-Wheeler gauge. Our solution thus represents a "bridge" between the test field solution, which neglects all the feedback terms, and the exact two-body solution, which takes into account all the non-linearity of the interaction.

Donato Bini; Andrea Geralico; Remo Ruffini

2014-08-20T23:59:59.000Z

327

Intrinsic trapping of stochastic sheared magnetic field lines  

Science Journals Connector (OSTI)

The decorrelation trajectory method is applied to the diffusion of magnetic field lines in a perturbed sheared slab magnetic configuration. Some interesting decorrelation trajectories for several values of the magnetic Kubo number and of the shear parameter are exhibited. The asymmetry of the decorrelation trajectories appears in comparison with those obtained in the purely electrostatic case studied in earlier work. The running and asymptotic diffusion tensor components are calculated and displayed.

M. Negrea; I. Petrisor; R. Balescu

2004-10-14T23:59:59.000Z

328

Materials Physics Applications: The National High Magnetic Field Laboratory  

NLE Websites -- All DOE Office Websites (Extended Search)

Search Search National High Magnetic Field Laboratory, NHMFL Home About Us Organization DIVISION Materials Physics and Applications Division GROUPS Superconductivity Technology Center Condensed Matter and Magnet Science Center for Integrated Nanotechnologies Sensors & Electrochemical Devices Materials Chemistry CONTACTS Group Leader Mike Hundley Director, NHMFL-PFF/Deputy Group Leader Chuck Mielke Head of Users Program Operations Jon Betts Professional Staff Assistant Julie T. Gallegos TA-03 Group Office TA-03, Building 0034, Room 101 Office Administrator Juanita Armijo TA-35 Group Office TA-35, Building 0127, Room C117 Office Administrator Angeline Willow 505-667-5032 National High Magnetic Field Laboratory, Pulsed Field Facility The Pulsed Field Facility at Los Alamos National Laboratory in Los Alamos, New Mexico, is one of three campuses of the National High Magnetic Field Laboratory (NHMFL), the other two being at Florida State University, Tallahassee (continuous fields, magnetic resonance, and general headquarters) and the University of Florida ,Gainesville(ultra-low temperatures at high magnetic fields). The NHMFL is sponsored primarily by the National Science Foundation, Division of Materials Research, with additional support from the State of Florida and the US Department of Energy.

329

CURRENT SHEETS FORMATION IN TANGLED CORONAL MAGNETIC FIELDS  

SciTech Connect

We investigate the dynamical evolution of magnetic fields in closed regions of solar and stellar coronae. To understand under which conditions current sheets form, we examine dissipative and ideal reduced magnetohydrodynamic models in Cartesian geometry, where two magnetic field components are present: the strong guide field B{sub 0}, extended along the axial direction, and the dynamical orthogonal field b. Magnetic field lines thread the system along the axial direction that spans the length L and are line-tied at the top and bottom plates. The magnetic field b initially has only large scales, with its gradient (current) length scale of the order of l{sub b}. We identify the magnetic intensity threshold b/B{sub 0} {approx} l{sub b}/L. For values of b below this threshold, field-line tension inhibits the formation of current sheets, while above the threshold they form quickly on fast ideal timescales. In the ideal case, above the magnetic threshold, we show that current sheets thickness decreases in time until it becomes smaller than the grid resolution, with the analyticity strip width {delta} decreasing at least exponentially, after which the simulations become underresolved.

Rappazzo, A. F. [Bartol Research Institute, Department of Physics and Astronomy, University of Delaware, Newark, DE 19716 (United States); Parker, E. N., E-mail: franco.rappazzo@gmail.com, E-mail: parker@oddjob.uchicago.edu [Enrico Fermi Institute, University of Chicago, Chicago, IL 60637 (United States)

2013-08-10T23:59:59.000Z

330

Quasi-two-dimensional excitons in finite magnetic fields  

Science Journals Connector (OSTI)

We present a theoretical and experimental investigation of the effects of a magnetic field on quasi-two-dimensional excitons. We calculate the internal structures and dispersion relations of spatially direct and indirect excitons in single and coupled quantum wells in a magnetic field perpendicular to the well plane. We find a sharp transition from a hydrogenlike exciton to a magnetoexciton with increasing the center-of-mass momentum at fixed weak field. At that transition the mean electron-hole separation increases sharply and becomes ?P/B?, where P is the magnetoexciton center-of-mass momentum and B? is the magnetic field perpendicular to the quantum well plane. The transition resembles a first-order phase transition. The magnetic-field–exciton momentum phase diagram describing the transition is constructed. We measure the magnetoexciton dispersion relations and effective masses in GaAs/Al0.33Ga0.67As coupled quantum wells using tilted magnetic fields. The calculated dispersion relations and effective masses are in agreement with the experimental data. We discuss the impact of magnetic field and sample geometry on the condition for observing exciton condensation.

Yu. E. Lozovik, I. V. Ovchinnikov, S. Yu. Volkov, L. V. Butov, and D. S. Chemla

2002-05-24T23:59:59.000Z

331

The discharge characteristics of the DUHOCAMIS with a high magnetic bottle-shaped field  

E-Print Network (OSTI)

For the purpose to produce high intensity, multiply charged metal ion beams, the DUHOCAMIS (dual hollow cathode ion source for metal ions) was derived from the hot cathode Penning ion source combined with the hollow cathode sputtering experiments in 2007. It was interesting to investigate the behavior of this discharge geometry in a stronger magnetic bottle-shaped field. So a new test bench for DUHOCAMIS with a high magnetic bottle-shaped field up to 0.6 T has been set up at Peking University, on which have been made primary experiments in connection with discharge characteristics of the source. The experiments with magnetic fields from 0.13 T to 0.52 T have shown that the magnetic flux densities are very sensitive to the discharge behavior: discharge curves and ion spectra. It has been found that the slope of discharge curves in a very wide range can be controlled by changing the magnetic field as well as regulated by adjusting cathode heating power. On the other hand, by comparison of discharge curves betwe...

Fu, Dongpo; Guo, Peng; Zhu, Kun; Wang, Jinghui; Hua, Jingshan; Ren, Xiaotang; Xue, Jianming; Zhao, Hongwei; Liu, Kexin

2014-01-01T23:59:59.000Z

332

Electromagnetic field of a charge intersecting a cold plasma boundary in a waveguide  

SciTech Connect

We analyze the electromagnetic field of a charge crossing a boundary between a vacuum and cold plasma in a waveguide. We obtain exact expressions for the field components and the spectral density of the transition radiation. With the steepest descent technique, we investigate the field components. We show that the electromagnetic field has a different structure in a vacuum than in cold plasma. We also develop an algorithm for the computation of the field based on a certain transformation of the integration path. The behavior of the field depending on distance and time and the spectral density depending on frequency are explored for different charge velocities. Some important physical effects are noted. A considerable increase and concentration of the field near the wave front in the plasma is observed for the case of ultrarelativistic particles. In the plasma, the mode envelopes and spectral density show zero points when the charge velocity is within certain limits.

Alekhina, Tatiana Yu.; Tyukhtin, Andrey V. [Radiophysics Department of St. Petersburg University, 1 Ulyanovskaya, St. Petersburg 198504 (Russian Federation)

2011-06-15T23:59:59.000Z

333

Bio-Med Variable Field MRI Project | Superconducting Magnet Division  

NLE Websites -- All DOE Office Websites (Extended Search)

Bio-Med Variable Field MRI Project Bio-Med Variable Field MRI Project One of the Research and Development projects currently underway is the Bio-Med magnet. Destined for use within the solenoidal field of an MRI, it is designed for use where the subject, in this case a rat, must be tracked in order to obtain an image. Typical MRIs require the subject to remain stationary, and a rat will not normally oblige when it is awake. By moving the composite field (MRI Solenoid plus Bio-Med dipole) to track the rat, it is possible to allow the rat some freedom of motion, while still imaging the brain functions. For the rapid movement typical of a rat, the Bio-Med coil magnet must be capable of very rapid changes in field. Superconducting magnets are typically not designed to allow rapid field variations. To do so typically

334

Magnetic Moment of Vector Mesons in the Background Field Method  

E-Print Network (OSTI)

We report some results for the magnetic moments of vector mesons extracted from mass shifts in the presence of static external magnetic fields. The calculations are done on $24^4$ quenched lattices using standard Wilson actions, with $\\beta$=6.0 and pion mass down to 500 MeV. The results are compared to those from the form factor method.

Frank X. Lee; Scott Moerschbacher; Walter Wilcox

2007-10-11T23:59:59.000Z

335

New approaches to thermoelectric cooling effects in magnetic fields  

SciTech Connect

The authors review thermoelectric effects in a magnetic field at a phenomenological level. Discussions of the limiting performance and problems with its computation for both Peltier and Ettingshausen coolers are presented. New principles to guide the materials scientists are discussed for magnetic effects, and a brief review of the subtle measurement problems is presented.

Migliori, A.; Darling, T.W.; Freibert, F. [and others

1997-05-01T23:59:59.000Z

336

Design of Compound Solenoids to Produce Highly Homogeneous Magnetic Fields  

Science Journals Connector (OSTI)

......the size of the correcting coils. An elementary hill-climbing routine adjusts S to...which contains a magnetic field but no electric currents, V x H = 0, and a magnetic...to the length of wire used and to the resistance of that wire. Thus thefieldi/n,m......

S. T. LONEY

1966-06-01T23:59:59.000Z

337

Magnetic fields of neutron stars in X-ray binaries  

E-Print Network (OSTI)

A substantial fraction of the known neutron stars resides in X-ray binaries -- systems in which one compact object accretes matter from a companion star. Neutron stars in X-ray binaries have magnetic fields among the highest found in the Universe, spanning at least the range from $\\sim10^8$ to several 10$^{13}$ G. The magnetospheres around these neutron stars have a strong influence on the accretion process, which powers most of their emission. The magnetic field intensity and geometry, are among the main factors responsible for the large variety of spectral and timing properties observed in the X-ray energy range, making these objects unique laboratories to study the matter behavior and the radiation processes in magnetic fields unaccessible on Earth. In this paper we review the main observational aspects related to the presence of magnetic fields in neutron star X-ray binaries and some methods that are used to estimate their strength.

Revnivtsev, Mikhail

2014-01-01T23:59:59.000Z

338

Magnetic field exposure and arrythmic risk: evaluation in railway drivers  

Science Journals Connector (OSTI)

The environmental monitoring of ELF-EMF reported in the official documentation of the firm on examination was performed with the following: an isotrope meter of static magnetic fields Metrolab ETM-1; an isotrope ...

L. Santangelo; M. Di Grazia; F. Liotti…

2005-05-01T23:59:59.000Z

339

EMDEX (Electric and Magnetic Field Digital EXposure) system manuals  

SciTech Connect

The EPRI Electric and Magnetic Field Digital EXposure (EMDEX) system consists of hardware and software for characterizing electric and magnetic field exposures. The EMDEX meter is a computer-based portable unit that samples, at a user-programmable rate, the three vector components of magnetic flux density, a measure of the average electric field acting on the torso of the wearer (if an optional sensor is worn) and a measure of rotational motion of the meter in the earth's magnetic field. Modules of the DATACALC software package are used to program the EMDEX, retrieve data at the end of a measurement session, analyze EMDEX data, and prepare tabular and graphical data summaries. The User Manual is designed to provide instruction on the use of the exposure system hardware and software. The Technical Reference Manual provides additional, detailed descriptions of the hardware, software and methodologies used in the EMDEX system.

Not Available

1989-10-01T23:59:59.000Z

340

Background ELF Magnetic Fields in a Great Urban Area  

Science Journals Connector (OSTI)

Epidemiologic evidences about increasing of risk of tumoral pathology incidence for group of subjects exposed to ELF magnetic field levels greater than established thresholds (cut-off points) stress the import...

Giovanni d’Amore; Laura Anglesio…

1999-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "magnetic field charged" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Advanced measurements and techniques in high magnetic fields  

SciTech Connect

This is the final report of a one-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). High magnetic fields present a unique environment for studying the electronic structure of materials. Two classes of materials were chosen for experiments at the national high Magnetic Field Laboratory at Los Alamos: highly correlated electron systems and semiconductors. Magnetotransport and thermodynamic experiments were performed on the renormalized ground states of highly correlated electron systems (such as heavy fermion materials and Kondo insulators) in the presence of magnetic fields that are large enough to disrupt the many-body correlations. A variety of optical measurements in high magnetic fields were performed on semiconductor heterostructures including GaAs/AlGaAs single heterojunctions (HEMT structure), coupled double quantum wells (CDQW), asymmetric coupled double quantum wells (ACDQW), multiple quantum wells and a CdTe single crystal thin film.

Campbell, L.J.; Rickel, D.G. [Los Alamos National Lab., NM (United States); Lacerda, A.H. [Florida State Univ., Tallahassee, FL (United States); Kim, Y. [Northeastern Univ., Boston, MA (United States)

1997-07-01T23:59:59.000Z

342

alternating magnetic fields: Topics by E-print Network  

NLE Websites -- All DOE Office Websites (Extended Search)

attention on recent progresses. Massimo Giovannini 2006-12-14 32 Cosmological Magnetic Fields vs. CMB Astrophysics (arXiv) Summary: I present a short review of the effects of a...

343

National High Magnetic Field Laboratory Slideshow: How to Make...  

NLE Websites -- All DOE Office Websites (Extended Search)

easy, fun and most can be done with stuff you have around the house. Compasses in Magnetic Fields Experiment with the compass in this tutorial to see how it responds to...

344

MagLab - Magnetic Field of a Solenoid Tutorial  

NLE Websites -- All DOE Office Websites (Extended Search)

Magnetic Field of a Solenoid This is a Java tutorial, which requires that you have Java, a free software, installed on your computer. It works best if you have the latest version...

345

National High Magnetic Field Laboratory: Museum of Electricity...  

NLE Websites -- All DOE Office Websites (Extended Search)

of the composition of light. Light, of course, is a form of energy. A magnetic field changes the behavior of light - a phenomenon known as the Zeeman effect. The Zeeman...

346

National High Magnetic Field Laboratory - Flux: Volume 3, Issue...  

NLE Websites -- All DOE Office Websites (Extended Search)

not Stephanie Law, who was practially an old-timer when she arrived at the Mag Lab. gauss lines Pregnancy to pacemakers: safety around high magnetic fields First things first......

347

The representation of magnetic field lines from magnetograph data  

Science Journals Connector (OSTI)

Several methods currently used to extrapolate the structure of the solar magnetic field from surface measurements are examined and compared. In particular, the differences between the methods of Schmidt for po...

Randolph H. Levine

1975-10-01T23:59:59.000Z

348

Port hole perturbations to the magnetic field in MST  

NLE Websites -- All DOE Office Websites (Extended Search)

095002 (17pp) doi:10.10880741-3335529095002 Port hole perturbations to the magnetic field in MST P J Fimognari 1 , A F Almagri 1 , J K Anderson 1 , D R Demers 2 , J S Sarff 1 ,...

349

National High Magnetic Field Laboratory - Try This at Home  

NLE Websites -- All DOE Office Websites (Extended Search)

fun and most can be done with stuff you have around the house. Create your own magnetic field lines, expose the iron in your cereal, or make an electromagnet from scratch Your...

350

National High Magnetic Field Laboratory - Ion Cyclotron Resonance...  

NLE Websites -- All DOE Office Websites (Extended Search)

of Radial Ion Motion in RF-Only Multipole Ion Guides Immersed in a Strong Magnetic Field Gradient, J. Am. Soc. Mass Spectr., 22, 591-601 (2011) 2 Blakney, G.T.; Hendrickson,...

351

Science in High Magnetic Fields: What Could Be Learned?  

Science Journals Connector (OSTI)

High magnetic fields are one of the most powerful tools available to scientists for the study, modification and control of matter. This includes the knowledge on correlations effects, interaction mechanisms, s...

G. Martinez

2003-10-01T23:59:59.000Z

352

Magnetic Fields of the Satellites of Jupiter and Saturn  

Science Journals Connector (OSTI)

This paper reviews the present state of knowledge about the magnetic fields and the plasma interactions associated with the major satellites of Jupiter and Saturn. As revealed by the data from a number of spac...

Xianzhe Jia; Margaret G. Kivelson; Krishan K. Khurana…

2010-05-01T23:59:59.000Z

353

National High Magnetic Field Laboratory - Making a Compass Activity  

NLE Websites -- All DOE Office Websites (Extended Search)

the south pole of the other. This is why compasses work on the Earth. The Earths magnetic field is strong enough to make the north pole of a very light compass needle align...

354

Solar nebula magnetic fields recorded in the Semarkona meteorite  

E-Print Network (OSTI)

Magnetic fields are proposed to have played a critical role in some of the most enigmatic processes of planetary formation by mediating the rapid accretion of disk material onto the central star and the formation of the ...

Fu, Roger Rennan

355

National High Magnetic Field Laboratory: Museum of Electricity...  

NLE Websites -- All DOE Office Websites (Extended Search)

it lacked sophistication, he was able to use the model to formulate his own law of magnetism. Magnetometers are used in many different fields; they are used in geophysics,...

356

Magnetic Fields in High-Density Stellar Matter  

E-Print Network (OSTI)

I briefly review some aspects of the effect of magnetic fields in the high density regime relevant to neutron stars, focusing mainly on compact star structure and composition, superconductivity, combustion processes, and gamma ray bursts.

German Lugones

2005-04-20T23:59:59.000Z

357

Primordial magnetic fields and formation of molecular hydrogen  

E-Print Network (OSTI)

We study the implications of primordial magnetic fields for the thermal and ionization history of the post-recombination era. In particular we compute the effects of dissipation of primordial magnetic fields owing to ambipolar diffusion and decaying turbulence in the intergalactic medium (IGM) and the collapsing halos and compute the effects of the altered thermal and ionization history on the formation of molecular hydrogen. We show that, for magnetic field strengths in the range $2 \\times 10^{-10} {\\rm G} \\la B_0 \\la 2 \\times 10^{-9} {\\rm G}$, the molecular hydrogen fraction in IGM and collapsing halo can increase by a factor 5 to 1000 over the case with no magnetic fields. We discuss the implication of the increased molecular hydrogen fraction on the radiative transfer of UV photons and the formation of first structures in the universe.

Shiv K Sethi; Biman B. Nath; Kandaswamy Subramanian

2008-04-22T23:59:59.000Z

358

Rigid and differential plasma crystal rotation induced by magnetic fields U. Konopka, D. Samsonov,* A. V. Ivlev,  

E-Print Network (OSTI)

- frequency wave propagation 10­12 . In a typical dusty plasma experiment in a radio-frequency rf discharge charge and the screening length. These parameters are assumed to be averaged over the rf-induced high-frequency in the sheath of a radio-frequency discharge, rotate under the influence of a vertical magnetic field. Depending

Goree, John

359

Parallel heat transport in integrable and chaotic magnetic fields  

SciTech Connect

The study of transport in magnetized plasmas is a problem of fundamental interest in controlled fusion, space plasmas, and astrophysics research. Three issues make this problem particularly challenging: (i) The extreme anisotropy between the parallel (i.e., along the magnetic field), {chi}{sub ||} , and the perpendicular, {chi}{sub Up-Tack }, conductivities ({chi}{sub ||} /{chi}{sub Up-Tack} may exceed 10{sup 10} in fusion plasmas); (ii) Nonlocal parallel transport in the limit of small collisionality; and (iii) Magnetic field lines chaos which in general complicates (and may preclude) the construction of magnetic field line coordinates. Motivated by these issues, we present a Lagrangian Green's function method to solve the local and non-local parallel transport equation applicable to integrable and chaotic magnetic fields in arbitrary geometry. The method avoids by construction the numerical pollution issues of grid-based algorithms. The potential of the approach is demonstrated with nontrivial applications to integrable (magnetic island), weakly chaotic (Devil's staircase), and fully chaotic magnetic field configurations. For the latter, numerical solutions of the parallel heat transport equation show that the effective radial transport, with local and non-local parallel closures, is non-diffusive, thus casting doubts on the applicability of quasilinear diffusion descriptions. General conditions for the existence of non-diffusive, multivalued flux-gradient relations in the temperature evolution are derived.

Castillo-Negrete, D. del; Chacon, L. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-8071 (United States)

2012-05-15T23:59:59.000Z

360

Parallel heat transport in integrable and chaotic magnetic fields  

SciTech Connect

The study of transport in magnetized plasmas is a problem of fundamental interest in controlled fusion, space plasmas, and astrophysics research. Three issues make this problem particularly chal- lenging: (i) The extreme anisotropy between the parallel (i.e., along the magnetic field), , and the perpendicular, , conductivities ( / may exceed 1010 in fusion plasmas); (ii) Magnetic field lines chaos which in general complicates (and may preclude) the construction of magnetic field line coordinates; and (iii) Nonlocal parallel transport in the limit of small collisionality. Motivated by these issues, we present a Lagrangian Green s function method to solve the local and non-local parallel transport equation applicable to integrable and chaotic magnetic fields in arbitrary geom- etry. The method avoids by construction the numerical pollution issues of grid-based algorithms. The potential of the approach is demonstrated with nontrivial applications to integrable (magnetic island chain), weakly chaotic (devil s staircase), and fully chaotic magnetic field configurations. For the latter, numerical solutions of the parallel heat transport equation show that the effective radial transport, with local and non-local closures, is non-diffusive, thus casting doubts on the appropriateness of the applicability of quasilinear diffusion descriptions. General conditions for the existence of non-diffusive, multivalued flux-gradient relations in the temperature evolution are derived.

Del-Castillo-Negrete, Diego B [ORNL; Chacon, Luis [ORNL

2012-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "magnetic field charged" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Phase-field simulation of electric-field-induced in-plane magnetic domain switching in magnetic/ferroelectric layered heterostructures  

E-Print Network (OSTI)

Phase-field simulation of electric-field-induced in-plane magnetic domain switching in magnetic. Phys. Lett. 99, 182510 (2011) Quantum tunneling of the Bloch point in a magnetic film with strong uniaxial magnetic anisotropy Low Temp. Phys. 37, 690 (2011) Evolution of magnetic bubble domains

Chen, Long-Qing

362

Two-dimensional Vlasov solution for a collisionless plasma jet across transverse magnetic field lines with a sheared bulk velocity  

Science Journals Connector (OSTI)

We consider a two-dimensional (2D) stationary stream of a collisionless plasma injected across an external stationary magnetic field and a background stagnant plasma. The solution is found by solving the Vlasov equation for each species (electrons and protons), the Maxwell-Ampere equation for the magnetic vector potential, and the equation of plasma quasineutrality for the electrostatic potential. The solution of the stationary Vlasov equation is given in terms of two constants of motion and one adiabatic invariant. The partial charge and current densities are given by analytical expressions of the moments of the velocity distribution functions for each particle species. The 2D distribution of the plasma bulk velocity, Vx(y,z), is roughly uniform inside the jet. There is no plasma bulk flow in the direction of the magnetic field. Inside the boundary layer interfacing the jet and the stagnant plasma, the bulk velocity has gradients (i.e., shears) in the direction parallel as well perpendicular to the magnetic field. The parallel component of this gradient, ??V?, produces a nonzero electric field component parallel to the magnetic field lines, E?B?0. The parallel electric field within the transition layer is a basic element allowing plasma elements to be transported across magnetic field lines in astrophysical systems as well as in laboratory experiments where plasmoids are injected across magnetic fields.

Marius M. Echim and Joseph F. Lemaire

2005-09-13T23:59:59.000Z

363

Mon. Not. R. Astron. Soc. 317, 4554 (2000) Global structure of self-excited magnetic fields arising from the magnetic  

E-Print Network (OSTI)

for small scales. The outer surface of the shell is penetrated by magnetic field lines in spot-like regionsMon. Not. R. Astron. Soc. 317, 45±54 (2000) Global structure of self-excited magnetic fields July 5 A B S T R AC T The global structure of a self-excited magnetic field arising from the magnetic

Haase, Markus

364

Zigzag nanoribbons in external electric and magnetic fields  

Science Journals Connector (OSTI)

We consider the Schrodinger operators on zigzag nanoribbons (tight-binding models) in external magnetic and electric fields. If these fields are absent, then the spectrum of the Schrodinger operator consists of two non-flat bands and one flat band (an eigenvalue with infinite multiplicity) between them. We describe all magnetic and electric fields for which the unperturbed flat band remains the flat band and when one splits into the small band of the continuous spectrum. Also we determine spectral asymptotics for small fields and solve inverse spectral problem.

Evgeny L. Korotyaev; Anton A. Kutsenko

2010-01-01T23:59:59.000Z

365

E-Print Network 3.0 - arbitrary magnetic field Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

magnetic field Search Powered by Explorit Topic List Advanced Search Sample search results for: arbitrary magnetic field Page: << < 1 2 3 4 5 > >> 1 Progress In Electromagnetics...

366

E-Print Network 3.0 - axisymmetric magnetic field Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

magnetic field Search Powered by Explorit Topic List Advanced Search Sample search results for: axisymmetric magnetic field Page: << < 1 2 3 4 5 > >> 1 Magnetohydrodynamics in...

367

E-Print Network 3.0 - alternative magnetic fields Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

the interface between two immiscible liquids and energized by an alternating magnetic field. Depending... on the frequency and amplitude of magnetic field, a variety of dynamic...

368

In situ electric fields causing electro-stimulation from conductor contact of charged human  

Science Journals Connector (OSTI)

......evolution of in situ electric fields in anatomically...the resultant in situ electric fields from a charged...Then, computed in situ electric fields were compared...magnitude of a capacitive discharge is much milder if the...object rather than an arc to the finger tip. Thus......

Toshihiro Nagai; Akimasa Hirata

2010-08-01T23:59:59.000Z

369

Attempts to elicit an evoked potential in the pigeon using a magnetic field stimulus  

E-Print Network (OSTI)

) and Wilkinson (1949) all objected to Yeagley's hypothesis on the grounds of physics. When a conductive element is moved through a magnetic field, an emf (electromotive force) is induced in the element due to a separation of charges. Hence, assuming... the pigeon may be sensitive to an induced emf in the bloodstream. Schumacher 17 I (1949) proposed that the movement of the bird' s wings across ~ the earth' s field may induce measurable AC voltages. I Stewart's hypothesis that a flying bird builds up...

Randolph, William Robert

2012-06-07T23:59:59.000Z

370

Carbon nanotubes in almost homogeneous transverse magnetic field: exactly solvable model  

E-Print Network (OSTI)

Single-wall carbon nanotubes are considered in the presence of an external magnetic field with inhomogeneous transverse component. The continuum model is employed where the dynamics of the charge carriers is governed by the Dirac-Weyl equation. It is shown that a small fluctuation of the transverse field around a constant value represented by a finite-gap vector potential provides exact solutions of the stationary equation. An example is elaborated in detail. The spectrum of the system manifests remarkable stability with respect to small perturbations of the longitudinal momentum. Nonlinear, N=2 supersymmetry associated with the metallic and the maximally semi-conducting nanotubes is discussed.

Jakubsky, Vit; Negro, Javier

2013-01-01T23:59:59.000Z

371

The Helioseismic and Magnetic Imager (HMI) Vector Magnetic Field Pipeline: Overview and Performance  

E-Print Network (OSTI)

The Helioseismic and Magnetic Imager (HMI) began near-continuous full-disk solar measurements on 1 May 2010 from the Solar Dynamics Observatory (SDO). An automated processing pipeline keeps pace with observations to produce observable quantities, including the photospheric vector magnetic field, from sequences of filtergrams. The primary 720s observables were released in mid 2010, including Stokes polarization parameters measured at six wavelengths as well as intensity, Doppler velocity, and the line-of-sight magnetic field. More advanced products, including the full vector magnetic field, are now available. Automatically identified HMI Active Region Patches (HARPs) track the location and shape of magnetic regions throughout their lifetime. The vector field is computed using the Very Fast Inversion of the Stokes Vector (VFISV) code optimized for the HMI pipeline; the remaining 180 degree azimuth ambiguity is resolved with the Minimum Energy (ME0) code. The Milne-Eddington inversion is performed on all full-di...

Hoeksema, J Todd; Hayashi, Keiji; Sun, Xudong; Schou, Jesper; Couvidat, Sebastien; Norton, Aimee; Bobra, Monica; Centeno, Rebecca; Leka, K D; Barnes, Graham; Turmon, Michael J

2014-01-01T23:59:59.000Z

372

Generalized charge simulation method for the calculation of the electric field in high voltage substations  

Science Journals Connector (OSTI)

This paper deals with the calculation of the electric field strength in high voltage (HV) substations comprising complex geometrical structures. Generalized charge simulation ... is to examine the influence of to...

Aleksandar Rankovi?; Milan S. Savi?

2010-07-01T23:59:59.000Z

373

Ways to calculate electric fields in traction electric motor insulation by equivalent charge method  

Science Journals Connector (OSTI)

A procedure permitting one to calculate the electric fields in multilayer insulation based on the equivalent charge method is presented. Consideration of the new algorithm shows its fast response and proper ac...

A. V. Kireev; A. Yu. Bakhvalov; S. Yu. Knyazev…

2009-03-01T23:59:59.000Z

374

Stellar model atmospheres with magnetic line blanketing. III. The role of magnetic field inclination  

E-Print Network (OSTI)

Context. See abstract in the paper. Aims. In the last paper of this series we study the effects of the magnetic field, varying its strength and orientation, on the model atmosphere structure, the energy distribution, photometric colors and the hydrogen Balmer line profiles. We compare with the previous results for an isotropic case in order to understand whether there is a clear relation between the value of the magnetic field angle and model changes, and to study how important the additional orientational information is. Also, we examine the probable explanation of the visual flux depressions of the magnetic chemically peculiar stars in the context of this work. Methods. We calculated one more grid of the model atmospheres of magnetic A and B stars for different effective temperatures (Teff=8000K, 11000K, 15000K), magnetic field strengths (B=0, 5, 10, 40 kG) and various angles of the magnetic field (Omega=0-90 degr) with respect to the atmosphere plane. We used the LLmodels code which implements a direct method for line opacity calculation, anomalous Zeeman splitting of spectral lines, and polarized radiation transfer. Results. We have not found significant changes in model atmosphere structure, photometric and spectroscopic observables or profiles of hydrogen Balmer lines as we vary the magnetic field inclination angle Omega. The strength of the magnetic field plays the main role in magnetic line blanketing. We show that the magnetic field has a clear relation to the visual flux depressions of the magnetic CP stars. Conclusions. See abstract in the paper.

S. A. Khan; D. V. Shulyak

2006-07-20T23:59:59.000Z

375

Dynamical Fluctuating Charge Force Fields: The Aqueous Solvation of Amides  

E-Print Network (OSTI)

on the environment, is a convenient model for treating all of these effects: conformational changes, functional group/mol.3 The free energy difference between the two conformers in water,4,5 given by nuclear magnetic to the environment, is applied to the aqueous solvation of acetamide and trans- and cis- N-methylacetamide (NMA). Two

Berne, Bruce J.

376

Dynamics of Particles Around a Schwarzschild-like Black Hole in the Presence of Quintessence and Magnetic Field  

E-Print Network (OSTI)

We have investigated the dynamics of a neutral and a charged particle around a static and spherically symmetric black hole in the presence of quintessence matter and external magnetic field. We explore the conditions under which the particle moving around the black hole could escape to infinity after colliding with another particle. The innermost stable circular orbit (ISCO) for the particles are studied in detail. Mainly the dependence of ISCO on dark energy and on the presence of external magnetic field in the vicinity of black hole is discussed. By using the Lyapunov exponent, we compare the stabilities of the orbits of the particles in the presence and absence of dark energy and magnetic field. The expressions for the center of mass energies of the colliding particles near the horizon of the black hole are derived. The effective force on the particle due to dark energy and magnetic field in the vicinity of black hole is also discussed.

Mubasher Jamil; Saqib Hussain; Bushra Majeed

2014-04-28T23:59:59.000Z

377

T Tauri stellar magnetic fields: He I measurements  

E-Print Network (OSTI)

We present measurements of the longitudinal magnetic field in the circumstellar environment of seven classical T Tauri stars. The measurements are based on high-resolution circular spectropolarimetry of the He I 5876 emission line, which is thought to form in accretion streams controlled by a stellar magnetosphere. We detect magnetic fields in BP Tau, DF Tau and DN Tau, and detect statistically significant fields in GM Aur and RW Aur A at one epoch but not at others. We detect no field for DG Tau and GG Tau, with the caveat that these objects were observed at one epoch only. Our measurements for BP Tau and DF Tau are consistent, both in terms of sign and magnitude, with previous studies, suggesting that the characteristics of T Tauri magnetospheres are persistent over several years. We observed the magnetic field of BP Tau to decline monotonically over three nights, and have detected a peak field of 4kG in this object, the highest magnetic field yet observed in a T Tauri star. We combine our observations with results from the literature in order to perform a statistical analysis of the magnetospheric fields in BP Tau and DF Tau. Assuming a dipolar field, we determine a polar field of ~3kG and a dipole offset of 40deg for BP Tau, while DF Tau's field is consistent with a polar field of ~-4.5kG and a dipole offset of 10deg. We conclude that many classical T Tauri stars have circumstellar magnetic fields that are both strong enough and sufficiently globally-ordered to sustain large-scale magnetospheric accretion flows.

Neil H. Symington; Tim J. Harries; Ryuichi Kurosawa; Tim Naylor

2005-01-20T23:59:59.000Z

378

2-3 High Field Magnetic Resonance Facility  

NLE Websites -- All DOE Office Websites (Extended Search)

HFMRF Overview HFMRF Overview High Field Magnetic Resonance Facility A significant portion of research conducted in the High Field Magnetic Resonance Facility (HFMRF) focuses on developing a fundamental, molecular-level understanding of biochemi- cal and biological systems and their response to environmental effects. A secondary focus is in materials science and catalysis and the chemical mechanisms and processes that operate in these areas. Resident and matrixed research staff within this facility offer expertise in the areas of structural biology, solid-state materials characterization, and magnetic resonance imaging (MRI) techniques. Instrumentation & Capabilities NMR * 900-MHz NMR (operational in 2004) * 800-MHz NMR * 750-MHz NMR * 600-MHz NMR (2 systems)

379

Effects of the 9-T magnetic field on MRS photodiode  

SciTech Connect

The experimental results on the performance of the MRS (Metal/Resistor/Semiconductor) photodiode in the strong magnetic field of 9T, and the possible impact of the quench of the magnet at 9.5T on sensor's operation are reported. The measurement method used is being described. The results of the work agree with the expectations that the MRS photodiode is not exhibiting sensitivity to the magnetic field presence. This result is essential for the design of the future electron-positron linear collider detector.

Beznosko, D.; Blazey, G.; Dyshkant, A.; Rykalin, V.; /Northern Illinois U.

2005-10-01T23:59:59.000Z

380

MRS Photodiode, LED and extruded scintillator performance in magnetic field  

SciTech Connect

The experimental results on the performance of the MRS (Metal/Resistor/Semiconductor) photodiode in the strong magnetic field of 4.4T, and the possible impact of the quench of the magnet at 4.5T on sensor's operation are reported. In addition, the experimental results on the performance of the extruded scintillator and WLS fiber, and various LEDs in the magnetic fields of 1.8T and 2.3T respectively, are detailed. The measurement method used is being described.

Beznosko, D.; Blazey, G.; Dyshkant, A.; Francis, K.; Kubik, D.; Rykalin, V.; Zutshi, V.; /Northern Illinois U.

2005-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "magnetic field charged" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

The influence of the magnetic field on the performance of an active magnetic regenerator (AMR)  

E-Print Network (OSTI)

The influence of the time variation of the magnetic field, termed the magnetic field profile, on the performance of a magnetocaloric refrigeration device using the active magnetic regeneration (AMR) cycle is studied for a number of process parameters for both a parallel plate and packed bed regenerator using a numerical model. The cooling curve of the AMR is shown to be almost linear far from the Curie temperature of the magnetocaloric material. It is shown that a magnetic field profile that is 10% of the cycle time out of sync with the flow profile leads to a drop in both the maximum temperature span and the maximum cooling capacity of 20-40\\% for both parallel plate and packed bed regenerators. The maximum cooling capacity is shown to depend very weakly on the ramp rate of the magnetic field. Reducing the temporal width of the high field portion of the magnetic field profile by 10% leads to a drop in maximum temperature span and maximum cooling capacity of 5-20%. An increase of the magnetic field from 1 T t...

Bjørk, R

2014-01-01T23:59:59.000Z

382

RESOLVED MAGNETIC FIELD MAPPING OF A MOLECULAR CLOUD USING GPIPS  

SciTech Connect

We present the first resolved map of plane-of-sky magnetic field strength for a quiescent molecular cloud. GRSMC 45.60+0.30 subtends 40 Multiplication-Sign 10 pc at a distance of 1.88 kpc, masses 16,000 M{sub Sun }, and exhibits no star formation. Near-infrared background starlight polarizations were obtained for the Galactic Plane Infrared Polarization Survey using the 1.8 m Perkins telescope and the Mimir instrument. The cloud area of 0.78 deg{sup 2} contains 2684 significant starlight polarizations for Two Micron All Sky Survey matched stars brighter than 12.5 mag in the H band. Polarizations are generally aligned with the cloud's major axis, showing an average position angle dispersion of 15 {+-} 2 Degree-Sign and polarization of 1.8 {+-} 0.6%. The polarizations were combined with Galactic Ring Survey {sup 13}CO spectroscopy and the Chandrasekhar-Fermi method to estimate plane-of-sky magnetic field strengths, with an angular resolution of 100 arcsec. The average plane-of-sky magnetic field strength across the cloud is 5.40 {+-} 0.04 {mu}G. The magnetic field strength map exhibits seven enhancements or 'magnetic cores'. These cores show an average magnetic field strength of 8.3 {+-} 0.9 {mu}G, radius of 1.2 {+-} 0.2 pc, intercore spacing of 5.7 {+-} 0.9 pc, and exclusively subcritical mass-to-flux ratios, implying their magnetic fields continue to suppress star formation. The magnetic field strength shows a power-law dependence on gas volume density, with slope 0.75 {+-} 0.02 for n{sub H{sub 2}} {>=}10 cm{sup -3}. This power-law index is identical to those in studies at higher densities, but disagrees with predictions for the densities probed here.

Marchwinski, Robert C.; Pavel, Michael D.; Clemens, Dan P., E-mail: robmarch@bu.edu, E-mail: pavelmi@bu.edu, E-mail: clemens@bu.edu [Institute for Astrophysical Research, Boston University, 725 Commonwealth Ave, Boston, MA 02215 (United States)

2012-08-20T23:59:59.000Z

383

Polarization of the vacuum of a quantized scalar field by an impenetrable magnetic vortex of finite thickness  

E-Print Network (OSTI)

We consider the effect of the magnetic field background in the form of a tube of the finite transverse size on the vacuum of the quantized charged massive scalar field which is subject to the Dirichlet boundary condition at the tube. It is shown that, if the Compton wavelength associated with the scalar field exceeds considerably the transverse size of the tube, then the vacuum energy which is finite and periodic in the value of the magnetic flux enclosed in the tube is induced on a plane transverse to the tube. Some consequences for generic features of the vacuum polarization in the cosmic-string background are discussed.

V. M. Gorkavenko; Yu. A. Sitenko; O. B. Stepanov

2009-11-15T23:59:59.000Z

384

Er3+-doped Nanoparticles for Optical Detection of Magnetic Field  

Science Journals Connector (OSTI)

In this work, we have studied an effect of magnetic field up to 50 T on emission spectrum of Er3+ in Er3+-doped nanoparticles prepared by chemical etching of the respective bulk nano-glass-ceramics template and found a unique strong effect of the magnetic field on the integral intensity of the 4S3/2?4I15/2 green emission line while integral intensities of other visible emission lines were only slightly affected. ... Figure 2. 4.2 K spectra of the 4S3/2?4I15/2 luminescence band of Er3+-doped nanoparticles in different pulsed magnetic fields (pulsed field flat plateau is about 5 ms); the intensity of luminescence decreases with applied field (a). ...

Victor K. Tikhomirov; Liviu F. Chibotaru; Damien Saurel; Patrick Gredin; Michel Mortier; Victor V. Moshchalkov

2009-01-07T23:59:59.000Z

385

Magnetic field dissipation in converging flows  

Science Journals Connector (OSTI)

......spatial distribution that mirrors that of the gas. This...i.e., several Schwarzschild radii) where the magnetic...turbulent distribution that mirrors that of the gas...radius of about 20 Schwarzschild radii. Our treatment...region, as far as 105 Schwarzschild radii, where the compact......

Fulvio Melia; Victor Kowalenko

2001-11-11T23:59:59.000Z

386

The effect of a direct current field on the microparticle charge in the plasma afterglow  

SciTech Connect

Residual charges of individual microparticles forming dense clouds were measured in a RF discharge afterglow. Experiments were performed under microgravity conditions on board the International Space Station, which ensured particle levitation inside the gas volume after the plasma switch-off. The distribution of residual charges as well as the spatial distribution of charged particles across the cloud were analyzed by applying a low-frequency voltage to the electrodes and measuring amplitudes of the resulting particle oscillations. Upon “free decharging” conditions, the charge distribution had a sharp peak at zero and was rather symmetric (with charges concentrated between ?10e and +10e), yet positively and negatively charged particles were homogeneously distributed over the cloud. However, when decharging evolved in the presence of an external DC field (applied shortly before the plasma switch-off) practically all residual charges were positive. In this case, the overall charge distribution had a sharp peak at about +15e and was highly asymmetric, while the spatial distribution exhibited a significant charge gradient along the direction of the applied DC field.

Wörner, L. [Max Planck Institute for extraterrestrial Physics, P.O. Box 1312, Giessenbachstr., 85741 Garching (Germany) [Max Planck Institute for extraterrestrial Physics, P.O. Box 1312, Giessenbachstr., 85741 Garching (Germany); Groupe de Recherches sur l'Energétique des Milieux Ionisés, UMR7344, CNRS, Univ. Orléans, F-45067 Orléans (France); Ivlev, A. V.; Huber, P.; Hagl, T.; Thomas, H. M.; Morfill, G. E. [Max Planck Institute for extraterrestrial Physics, P.O. Box 1312, Giessenbachstr., 85741 Garching (Germany)] [Max Planck Institute for extraterrestrial Physics, P.O. Box 1312, Giessenbachstr., 85741 Garching (Germany); Couëdel, L. [Centre National de la Recherche Scientifique, Aix-Marseille-Université, Laboiratoire de Physique des Intéractions Ioniques et Moléculaires, UMR 7345, 13397 Marseille cedex 20 (France)] [Centre National de la Recherche Scientifique, Aix-Marseille-Université, Laboiratoire de Physique des Intéractions Ioniques et Moléculaires, UMR 7345, 13397 Marseille cedex 20 (France); Schwabe, M. [Max Planck Institute for extraterrestrial Physics, P.O. Box 1312, Giessenbachstr., 85741 Garching (Germany) [Max Planck Institute for extraterrestrial Physics, P.O. Box 1312, Giessenbachstr., 85741 Garching (Germany); Department of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, California 94720 (United States); Mikikian, M.; Boufendi, L. [Groupe de Recherches sur l'Energétique des Milieux Ionisés, UMR7344, CNRS, Univ. Orléans, F-45067 Orléans (France)] [Groupe de Recherches sur l'Energétique des Milieux Ionisés, UMR7344, CNRS, Univ. Orléans, F-45067 Orléans (France); Skvortsov, A. [Yuri Gagarin Cosmonauts Training Center, RU-141160 Star City (Russian Federation)] [Yuri Gagarin Cosmonauts Training Center, RU-141160 Star City (Russian Federation); Lipaev, A. M.; Molotkov, V. I.; Petrov, O. F.; Fortov, V. E. [Joint Institute for High Temperatures, RU-125412 Moscow (Russian Federation)] [Joint Institute for High Temperatures, RU-125412 Moscow (Russian Federation)

2013-12-15T23:59:59.000Z

387

Tuning magnetic disorder in diluted magnetic semiconductors using high fields to 89 Tesla  

SciTech Connect

We describe recent and ongoing studies at the National High Magnetic Field Laboratory at Los Alamos using the new '100 Tesla Multi-Shot Magnet', which is presently delivering fields up to {approx}89 T during its commissioning. We discuss the first experiments performed in this magnet system, wherein the linewidth of low-temperature photoluminescence spectra was used to directly reveal the degree of magnetic alloy disorder 'seen' by excitons in single Zn{sub 0.80}Cd{sub 0.22}Mn{sub 0.08}Se quantum wells. The magnetic potential landscape in II-VI diluted magnetic semiconductors (DMS) is typically smoothed when the embedded Mn{sup 2+} spins align in an applied field. However, an important (but heretofore untested) prediction of current models of compositional disorder is that magnetic alloy fluctuations in many DMS compounds should increase again in very large magnetic fields approaching 100 T. We observed precisely this increase above {approx}70 T, in agreement with a simple model of magnetic alloy disorder.

Crooker, Scott A [Los Alamos National Laboratory; Samarth, Nitin [PENN STATE U

2008-01-01T23:59:59.000Z

388

Image Charge Differential  

E-Print Network (OSTI)

Image Charge Differential Amplifier FT 0 Crude Oil Time (s) 543210 Frequency (kHz) m/z m q B f Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) uses the frequency of cyclotron motion of the ions in a static magnetic field to determine the mass-to-charge ratio, which is then used

Weston, Ken

389

Magnetic field exposure characterization during environmental field surveys for the EMF RAPID program  

SciTech Connect

The characteristics of magnetic fields in different environments are systematically collected under the RAPID Engineering Project {number_sign}3. Exposure to magnetic field is due to area sources and to local sources at exposure points. This paper presents only a summary of results concerning exposure to area sources. The data presented in this paper show that area fields differ significantly between sites of the same environments. This makes it difficult to characterize each environment type by a field value. Characteristics of the site, such as age and number of floors of the building, probably have a large effect on the magnetic field, independently on the specific use of the building. Magnetic field exposure at exposure points is likely to show a greater dependence on the environment type.

Zaffanella, L.E. [Enertech Consultants, Lee, MA (United States)

1996-10-01T23:59:59.000Z

390

Atomic magnetic gradiometer for room temperature high sensitivity magnetic field detection  

DOE Patents (OSTI)

A laser-based atomic magnetometer (LBAM) apparatus measures magnetic fields, comprising: a plurality of polarization detector cells to detect magnetic fields; a laser source optically coupled to the polarization detector cells; and a signal detector that measures the laser source after being coupled to the polarization detector cells, which may be alkali cells. A single polarization cell may be used for nuclear magnetic resonance (NMR) by prepolarizing the nuclear spins of an analyte, encoding spectroscopic and/or spatial information, and detecting NMR signals from the analyte with a laser-based atomic magnetometer to form NMR spectra and/or magnetic resonance images (MRI). There is no need of a magnetic field or cryogenics in the detection step, as it is detected through the LBAM.

Xu,Shoujun (Berkeley, CA); Lowery, Thomas L. (Belmont, MA); Budker, Dmitry (El Cerrito, CA); Yashchuk, Valeriy V. (Richmond, CA); Wemmer, David E. (Berkeley, CA); Pines, Alexander (Berkeley, CA)

2009-08-11T23:59:59.000Z

391

MAGNETIC FIELDS IN THE HR DIAGRAM Jeffrey L. Linsky  

E-Print Network (OSTI)

MAGNETIC FIELDS IN THE HR DIAGRAM Jeffrey L. Linsky JILA/University of Colorado and NIST Solar IN SOLAR AND STELLAR ATMOSPHERES Heating Processes: MHD wave processes, rapid field annihilation processes has different properties and cell sizes than nor­ mal convection Wind: Alfv'en waves and other MHD

Linsky, Jeffrey L.

392

Self-field and magnetic-flux quantum mechanics  

E-Print Network (OSTI)

Self-field and quantized magnetic-flux are employed to generate the quantum numbers n, m, and l of atomic physics. Wave-particle duality is shown to be a natural outcome of having a particle and its self-field.

Paul Harris

2005-04-06T23:59:59.000Z

393

Measurement of megagauss magnetic fields in a plasma focus device  

Science Journals Connector (OSTI)

The magnetic field associated with the dense pinch in a plasma focus device has been measured from the Zeeman splitting of the Cv, 2s-2p emission. Values of the order of 1 MG are derived, in agreement with pressure balance between the self-field due to currents in the pinch and the kinetic pressure of the plasma.

N. J. Peacock and B. A. Norton

1975-06-01T23:59:59.000Z

394

DOES MAGNETIC-FIELD-ROTATION MISALIGNMENT SOLVE THE MAGNETIC BRAKING CATASTROPHE IN PROTOSTELLAR DISK FORMATION?  

SciTech Connect

Stars form in dense cores of molecular clouds that are observed to be significantly magnetized. In the simplest case of a laminar (non-turbulent) core with the magnetic field aligned with the rotation axis, both analytic considerations and numerical simulations have shown that the formation of a large, 10{sup 2} AU scale, rotationally supported protostellar disk is suppressed by magnetic braking in the ideal MHD limit for a realistic level of core magnetization. This theoretical difficulty in forming protostellar disks is termed the ''magnetic braking catastrophe''. A possible resolution to this problem, proposed by Hennebelle and Ciardi and Joos et al., is that misalignment between the magnetic field and rotation axis may weaken the magnetic braking enough to enable disk formation. We evaluate this possibility quantitatively through numerical simulations. We confirm the basic result of Joos et al. that the misalignment is indeed conducive to disk formation. In relatively weakly magnetized cores with dimensionless mass-to-flux ratio {approx}> 4, it enabled the formation of rotationally supported disks that would otherwise be suppressed if the magnetic field and rotation axis are aligned. For more strongly magnetized cores, disk formation remains suppressed, however, even for the maximum tilt angle of 90 Degree-Sign . If dense cores are as strongly magnetized as indicated by OH Zeeman observations (with a mean dimensionless mass-to-flux ratio {approx}2), it would be difficult for the misalignment alone to enable disk formation in the majority of them. We conclude that, while beneficial to disk formation, especially for the relatively weak field case, misalignment does not completely solve the problem of catastrophic magnetic braking in general.

Li Zhiyun [Astronomy Department, University of Virginia, Charlottesville, VA (United States); Krasnopolsky, Ruben; Shang, Hsien [Academia Sinica, Theoretical Institute for Advanced Research in Astrophysics, Taipei, Taiwan (China)

2013-09-01T23:59:59.000Z

395

Treating Cancer with Strong Magnetic Fields and Ultrasound  

E-Print Network (OSTI)

It is proposed to treat cancer by the combination of a strong magnetic field with intense ultrasound. At the low electrical conductivity of tissue the magnetic field is not frozen into the tissue, and oscillates against the tissue which is brought into rapid oscillation by the ultrasound. As a result, a rapidly oscillating electric field is induced in the tissue, strong enough to disrupt cancer cell replication. Unlike radio frequency waves, which have been proposed for this purpose, ultrasound can be easily focused onto the regions to be treated. This method has the potential for the complete eradication of the tumor.

Dr. Friedwardt Winterberg

2009-06-03T23:59:59.000Z

396

Reconnection and the Ideal Evolution of Magnetic Fields  

Science Journals Connector (OSTI)

A magnetic evolution is ideal if it is consistent with the field being embedded in a perfectly conducting fluid. Faraday's law implies the evolution is ideal when the parallel component of the electric field is the derivative of a scalar potential, a condition that generically holds in any local region of space. Reconnection requires the non-existence of such a potential. In systems with two periodic directions, non-existence focuses reconnection onto the surfaces in which the magnetic field lines close on themselves, the rational surfaces. This rational surface effect does not arise in astrophysics but does appear in periodic simulation codes. Effects that could give astrophysical reconnection are discussed.

Allen H. Boozer

2002-05-13T23:59:59.000Z

397

Electronic properties of graphite in tilted magnetic fields  

SciTech Connect

The minimal nearest-neighbor tight-binding model with the Peierls substitution is employed to describe the electronic structure of Bernal-stacked graphite subject to tilted magnetic fields. We show that while the presence of the in-plane component of the magnetic field has a negligible effect on the Landau level structure at the K point of the graphite Brillouin zone, at the H point it leads to the experimentally observable splitting of Landau levels which grows approximately linearly with the in-plane field intensity.

Goncharuk, Nataliya A.; Smr?ka, Ludvík [Institute of Physics, Academy of Science of the Czech Republic, v. v. i., Cukrovarnická 10, 162 53 Praha 6 (Czech Republic)

2014-05-15T23:59:59.000Z

398

Electron Heat Transport Measured in a Stochastic Magnetic Field T. M. Biewer,* C. B. Forest,  

E-Print Network (OSTI)

where magnetic islands overlap and field lines are stochastic. The measurements show that (1 magnetic flux surfaces. When flux surfaces exist, magnetic field lines and hence particle orbits are small, the magnetic field lines break into chains of magnetic islands at mode-rational sur- faces where

Biewer, Theodore

399

Nuclear magnetic resonances in weak fields  

E-Print Network (OSTI)

first choax@ation of nuclear resonances in weak f le). de was sade by k 0, S~ in fiel4u of 6 and lg gauss using a sanple siue of. 1 liter, The nagnetic fields were produced in a solenoi4 pou?x?d by a bazdz of lead storage batteriesx an4 the resonances..., Tbe poser was pxovided for the static nagnetic field by a bank of 20 lead storage cells connected in ssriesi The current was a+usted to the desired value with a variable xesistanoe which was connected in sex'ies with the solenoid. Qm source of field...

Mitchell, Richard Warren

2012-06-07T23:59:59.000Z

400

Magnetic anisotropy in Fe-25Cr-12Co-1Si alloy induced by external magnetic field  

E-Print Network (OSTI)

Magnetic anisotropy in Fe-25Cr-12Co-1Si alloy induced by external magnetic field ZHEN Liang( )1 of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China; 2. Department. Curriculum in Applied and Materials Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC

Qin, Lu-Chang

Note: This page contains sample records for the topic "magnetic field charged" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

MAGNETIC POWER SPECTRA DERIVED FROM GROUND AND SPACE MEASUREMENTS OF THE SOLAR MAGNETIC FIELDS  

E-Print Network (OSTI)

of gas about in the photosphere, and will evidently act in the same way upon a magnetic line of force motion is by investigating the nature of the photospheric magnetic fields in terms Solar Physics 201: 225 with an energy cascade of turbulent motions. In the turbulent fluid motion, the kinetic energy cascades from

402

Influence of the Earth's magnetic field on large area photomultipliers  

SciTech Connect

The influence of the Earth's magnetic field on large area photomultipliers proposed for a future deep sea neutrino telescope was studied under the EU-funded KM3NeT design study. The aims were to evaluate variations in PMT performance in the Earth's magnetic field and to decide whether the use of magnetic shielding is necessary. Measurements were performed on three Hamamatsu PMTs: two 8-inch R5912 types, one of these with super-bi-alkali photocathode, and a 10-inch R7081 type with a standard bi-alkali photocathode. The various characteristics of the PMTs were measured while varying the PMT orientations with respect to the Earth's magnetic field, both with and without a mu-metal cage as magnetic shield. In the 8-inch PMTs the impact of the magnetic field was found to be smaller than that on the 10-inch PMT. The increased quantum efficiency in the 8 super-bi-alkali PMT almost compensated its smaller detection surface compared to the 10' PMT. No significant effects were measured upon transit time and the fraction of spurious pulses. (authors)

Leonora, E.; Aiello, S. [INFN - National Inst. of Nuclear Physics, Section of Catania, CO Via Santa Sofia 64, 95123 Catania (Italy); Leotta, G. [Dept. of Physics and Astronomy of Catania, CO Via Santa Sofia 64, 95123 Catania (Italy)

2011-07-01T23:59:59.000Z

403

National High Magnetic Field Laboratory: Metallic Superlattices  

NLE Websites -- All DOE Office Websites (Extended Search)

Many years would pass, however, before thin films became a major focus in the field of physics. The introduction of computers and the search for practical methods of data storage...

404

National High Magnetic Field Laboratory - Applied Superconductivity...  

NLE Websites -- All DOE Office Websites (Extended Search)

the coupling between the gaps, and whether this produces new properties when quantized field lines move along grain boundaries or when MgB2 is exposed to microwave radiation. The...

405

Simulations of magnetic field gradients due to micro-magnets on a triple quantum dot circuit  

SciTech Connect

To quantify the effects of local magnetic fields on triple quantum dots, the Heisenberg Hamiltonian has been diagonalized for three electrons coupled via the exchange interaction. In particular, we have investigated different geometries of micro-magnets located on top of the triple dot in order to optimize the field gradient characteristics. In this paper, we focus on two geometries which are candidates for an addressable EDSR triple quantum dot device.

Poulin-Lamarre, G. [National Research Council of Canada, Ottawa, On., Canada, K1A-0R6 and Département de physique, Université de Sherbrooke, Sherbrooke, Qc. J1K-2R1 (Canada); Bureau-Oxton, C. [Département de physique, Université de Sherbrooke, Sherbrooke, Qc. J1K-2R1 (Canada); Kam, A. [National Research Council of Canada, Ottawa, On. K1A-0R6 (Canada); Zawadzki, P.; Aers, G. [National Research Council of Canada, Ottawa, On. K1A-0R6 (Canada); Studenikin, S. [National Research Council of Canada, Ottawa, On.K1A-0R6 (Canada); Pioro-Ladrière, M. [Département de physique, Université de Sherbrooke, Sherbrooke, Qc. J1K-2R1 (Canada); Sachrajda, A. S. [National Research Council of Canada, Ottawa, On., Canada, K1A-0R6 and Département de physique, Université de Sherbrooke, Sherbrooke, Qc. J1K-2R1 (Canada)

2013-12-04T23:59:59.000Z

406

Neutrino transition magnetic moments and the solar magnetic field on the light of the Kamland evidence  

E-Print Network (OSTI)

We present here a recopilation of recent results about the possibility of detecting solar electron antineutrinos produced by solar core and convective magnetic fields. These antineutrinos are predicted by spin-flavor oscillations at a significant rate even if this mechanism is not the leading solution to the SNP. Using the recent Kamland results and assuming a concrete model for antineutrino production by spin-flavor precession in the convective zone based on chaotic magnetic fields,we obtain bounds on the flux of solar antineutrinos, on the average conversion neutrino-antineutrino probability and on intrinsic neutrino magnetic moment. In the most conservative case, $\\mu\\lsim 2.5\\times 10^{-11} \\mu_B$ (95% CL). When studying the effects of a core magnetic field, we find in the weak limit a scaling of the antineutrino probability with respect to the magnetic field profile in the sense that the same probability function can be reproduced by any profile with a suitable peak field value. In this way the solar electron antineutrino spectrum can be unambiguosly predicted. We use this scaling and the negative results indicated by the KamLAND experiment to obtain upper bounds on the solar electron antineutrino flux. We find that, for a wide family of magnetic field profiles in the sun interior, the antineutrino appearance probability is largely determined by the magnetic field intensity but not by its shape. Explicit limits on neutrino transition moments are also obtained consistent with the convective case. These limits are therefore largerly independent of the detailed structure of the magnetic field in the solar interior.

V. Antonelli; B. C. Chauhan; J. Pulido; E. Torrente-Lujan

2003-10-29T23:59:59.000Z

407

Vibrating H3+ in a Uniform Magnetic Field  

Science Journals Connector (OSTI)

Knowledge of how the rotation–vibrational states are affected by the interaction of the molecule with such a field would likely facilitate the detection of H3+ in the universe at locations with magnetic fields such as interstellar media. ... The contour lines clearly show the ridge at D3h configurations, R1 = R2. ... For arbitrary orientation of the field with respect to the line connecting the centers, the pertinent Schroedinger equation is solved by evaluating anal. ...

Héctor Medel Cobaxin; Alexander Alijah

2013-03-05T23:59:59.000Z

408

Energy confinement and magnetic field generation in the SSPX spheromaka)  

Science Journals Connector (OSTI)

The Sustained Spheromak Physics Experiment (SSPX) [Hooper et al. Nuclear Fusion39 863 (1999)] explores the physics of efficient magnetic field buildup and energy confinement both essential parts of advancing the spheromak concept. Extending the spheromak formation phase increases the efficiency of magnetic field generation with the maximum edge magnetic field for a given injector current ( B ? I ) from 0.65 T ? MA previously to 0.9 T ? MA . We have achieved the highest electron temperatures ( T e ) recorded for a spheromak with T e > 500 eV toroidalmagnetic field ? 1 T and toroidal current ( ? 1 MA ) [Wood et al. “Improved magnetic field generation efficiency and higher temperaturespheromakplasmas ” Phys. Rev. Lett. (submitted)]. Extending the sustainment phase to > 8 ms extends the period of low magnetic fluctuations ( input power and dominantly collisional majority ion heating. The evolution of electron temperature shows a distinct and robust feature of spheromak formation: A hollow-to-peaked T e ( r ) associated with q ? 1 ? 2 .

B. Hudson; R. D. Wood; H. S. McLean; E. B. Hooper; D. N. Hill; J. Jayakumar; J. Moller; D. Montez; C. A. Romero-Talamás; T. A. Casper; J. A. Johnson III; L. L. LoDestro; E. Mezonlin; L. D. Pearlstein

2008-01-01T23:59:59.000Z

409

Magnetic Field Switching of Nanoparticles between Orthogonal Microfluidic Channels  

Science Journals Connector (OSTI)

Permanent magnets have also been used together with integrated current lines to divert micrometer-sized magnetic beads within a microfluidic “Y” geometry,15 and antibody-coated microbeads immobilized in a microfluidic device were used in immunoassays for the sensitive detection of corresponding antigens. ... 35-37 The top piece (?5 mm thick) was formed by casting the PDMS (ratio of PDMS to curing agent was 15:1) over an aluminum master with a line measuring 320 ?m high and 200 ?m wide. ... Magnetic fields were applied using a NdFeB permanent magnet (circumference, 2.5 cm; height, 2.5 cm; field strength at edge, ?0.7 T; Engineered Concepts, Birmingham, AL). ...

Andrew H. Latham; Anand N. Tarpara; Mary Elizabeth Williams

2007-06-23T23:59:59.000Z

410

The Solar Magnetic Field as a Coronal Hole Extension Forms: Effects of Magnetic Helicity and Boundary Conditions  

Science Journals Connector (OSTI)

An analytical solution is presented for linear force fields within a spherical shell, representing the solar corona. Allowing for a global magnetic helicity, we find magnetic fields over the entire corona with...

J. R. Clegg; B. J. I. Bromage; P. K. Browning

411

Magnetic-field generation and electron acceleration in relativistic laser channel  

E-Print Network (OSTI)

Magnetic-field generation and electron acceleration in relativistic laser channel I. Yu. Kostyukov itself as a strong axial magnetic field inverse Faraday effect . The magnitude of this magnetic field is calculated and related to the amount of the absorbed energy. Absorbed energy and generated magnetic field

412

Asymmetric magnetic reconnection in the presence of a guide field P. L. Pritchett1  

E-Print Network (OSTI)

to the magnetic field and particle outflows along the field lines. Such a symmetric treatment of the diffusionAsymmetric magnetic reconnection in the presence of a guide field P. L. Pritchett1 and F. S. Mozer2] The properties of asymmetric magnetic reconnection in the presence of a guide magnetic field are investigated

California at Berkeley, University of

413

Memorandum Approval of a Permanenet Variance Regarding Static Magnetic Fields at Brookhaven National Laboratory (Variance 1021)  

Energy.gov (U.S. Department of Energy (DOE))

Approval of a Permanenet Variance Regarding Static Magnetic Fields at Brookhaven National Laboratory (Variance 1021)

414

Analysis of charge transport during lightning using balloon-borne electric field sensors and Lightning  

E-Print Network (OSTI)

a lightning flash have been obtained by a balloon-borne electric field sonde or Esonde. This paper developsAnalysis of charge transport during lightning using balloon-borne electric field sensors and Lightning Mapping Array William W. Hager,1 Richard G. Sonnenfeld,2 Beyza Caliskan Aslan,1 Gaopeng Lu,2

Hager, William

415

Behavior of nanoparticle clouds around a magnetized microsphere under magnetic and flow fields  

E-Print Network (OSTI)

When a micron-sized magnetizable particle is introduced into a suspension of nanosized magnetic particles, the nanoparticles accumulate around the microparticle and form thick anisotropic clouds extended in the direction of the applied magnetic field. This phenomenon promotes colloidal stabilization of bimodal magnetic suspensions and allows efficient magnetic separation of nanoparticles used in bioanalysis and water purification. In the present work, size and shape of nanoparticle clouds under the simultaneous action of an external uniform magnetic field and the flow have been studied in details. In experiments, dilute suspension of iron oxide nanoclusters (of a mean diameter of 60 nm) was pushed through a thin slit channel with the nickel microspheres (of a mean diameter of 50$\\mu$m) attached to the channel wall. The behavior of nanocluster clouds was observed in the steady state using an optical microscope. In the presence of strong enough flow, the size of the clouds monotonically decreases with increasing flow speed in both longitudinal and transverse magnetic fields. This is qualitatively explained by enhancement of hydrodynamic forces washing the nanoclusters away from the clouds. In the longitudinal field, the flow induces asymmetry of the front and the back clouds. To explain the flow and the field effects on the clouds, we have developed a simple model based on the balance of the stresses and particle fluxes on the cloud surface. This model, applied to the case of the magnetic field parallel to the flow, captures reasonably well the flow effect on the size and shape of the cloud and reveals that the only dimensionless parameter governing the cloud size is the ratio of hydrodynamic-to-magnetic forces - the Mason number. At strong magnetic interactions considered in the present work (dipolar coupling parameter $\\alpha \\geq 2$), the Brownian motion seems not to affect the cloud behavior.

Cécilia Magnet; Pavel Kuzhir; Georges Bossis; Alain Meunier; Sebastien Nave; Andrey Zubarev; Claire Lomenech; Victor Bashtovoi

2014-04-14T23:59:59.000Z

416

Nano- and Microstructures of Magnetic Field-Guided Maghemite Nanoparticles in Diblock Copolymer Films  

Science Journals Connector (OSTI)

The magnetic behavior of the hybrid films was probed at different temperatures for two orthogonal directions (with the line-shaped particle aggregates parallel and perpendicular to the magnetic field). ... The observations indicate that well-aligned, highly oriented metal-oxide lines can be obtained at low magnetic field strengths, such as 149 G, rather than at higher magnetic fields. ... Magnet-polymer (Magpol) composites have an interesting ability to undergo large strains in response to an external magnetic field. ...

Yuan Yao; Ezzeldin Metwalli; Martin A. Niedermeier; Matthias Opel; Chen Lin; Jing Ning; Jan Perlich; Stephan V. Roth; Peter Müller-Buschbaum

2014-03-12T23:59:59.000Z

417

The Cost of Superconducting Magnets as a Function of Stored Energy and Design Magnetic Induction Times the Field Volume  

SciTech Connect

By various theorems one can relate the capital cost of superconducting magnets to the magnetic energy stored within that magnet. This is particularly true for magnet where the cost is dominated by the structure needed to carry the magnetic forces. One can also relate the cost of the magnet to the product of the magnetic induction and the field volume. The relationship used to estimate the cost the magnet is a function of the type of magnet it is. This paper updates the cost functions given in two papers that were published in the early 1990 s. The costs (escalated to 2007 dollars) of large numbers of LTS magnets are plotted against stored energy and magnetic field time field volume. Escalated costs for magnets built since the early 1990 s are added to the plots.

Green, Mike; Green, M.A.; Strauss, B.P.

2007-08-27T23:59:59.000Z

418

MAGNETIC FIELD STRUCTURES TRIGGERING SOLAR FLARES AND CORONAL MASS EJECTIONS  

SciTech Connect

Solar flares and coronal mass ejections, the most catastrophic eruptions in our solar system, have been known to affect terrestrial environments and infrastructure. However, because their triggering mechanism is still not sufficiently understood, our capacity to predict the occurrence of solar eruptions and to forecast space weather is substantially hindered. Even though various models have been proposed to determine the onset of solar eruptions, the types of magnetic structures capable of triggering these eruptions are still unclear. In this study, we solved this problem by systematically surveying the nonlinear dynamics caused by a wide variety of magnetic structures in terms of three-dimensional magnetohydrodynamic simulations. As a result, we determined that two different types of small magnetic structures favor the onset of solar eruptions. These structures, which should appear near the magnetic polarity inversion line (PIL), include magnetic fluxes reversed to the potential component or the nonpotential component of major field on the PIL. In addition, we analyzed two large flares, the X-class flare on 2006 December 13 and the M-class flare on 2011 February 13, using imaging data provided by the Hinode satellite, and we demonstrated that they conform to the simulation predictions. These results suggest that forecasting of solar eruptions is possible with sophisticated observation of a solar magnetic field, although the lead time must be limited by the timescale of changes in the small magnetic structures.

Kusano, K.; Bamba, Y.; Yamamoto, T. T. [Solar-Terrestrial Environment Laboratory, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8601 (Japan); Iida, Y.; Toriumi, S. [Department of Earth and Planetary Science, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Asai, A., E-mail: kusano@nagoya-u.jp [Unit of Synergetic Studies for Space, Kyoto University, 17 Kitakazan Ohmine-cho, Yamashina-ku, Kyoto 607-8471 (Japan)

2012-11-20T23:59:59.000Z

419

Development of fast cooling pulsed magnets at the Wuhan National High Magnetic Field Center  

SciTech Connect

Pulsed magnets with fast cooling channels have been developed at the Wuhan National High Magnetic Field Center. Between the inner and outer sections of a coil wound with a continuous length of CuNb wire, G10 rods with cross section 4 mm × 5 mm were inserted as spacers around the entire circumference, parallel to the coil axis. The free space between adjacent rods is 6 mm. The liquid nitrogen flows freely in the channels between these rods, and in the direction perpendicular to the rods through grooves provided in the rods. For a typical 60 T pulsed magnetic field with pulse duration of 40 ms, the cooling time between subsequent pulses is reduced from 160 min to 35 min. Subsequently, the same technology was applied to a 50 T magnet with 300 ms pulse duration. The cooling time of this magnet was reduced from 480 min to 65 min.

Peng, Tao; Sun, Quqin; Zhao, Jianlong; Jiang, Fan; Li, Liang; Xu, Qiang [Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan (China)] [Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan (China); Herlach, Fritz [Department of Physics, Katholieke Universiteit Leuven, Celestijnenlaan 200D, B-3001 Leuven (Belgium)] [Department of Physics, Katholieke Universiteit Leuven, Celestijnenlaan 200D, B-3001 Leuven (Belgium)

2013-12-15T23:59:59.000Z

420

Spectroscopy of Charge Carriers and Traps in Field-Doped Organic Semiconductors  

SciTech Connect

This research project aims to achieve quantitative and molecular level understanding of charge carriers and traps in field-doped organic semiconductors via in situ optical absorption spectroscopy, in conjunction with time-resolved electrical measurements. During the funding period, we have made major progress in three general areas: (1) probed charge injection at the interface between a polymeric semiconductor and a polymer electrolyte dielectric and developed a thermodynamic model to quantitatively describe the transition from electrostatic to electrochemical doping; (2) developed vibrational Stark effect to probe electric field at buried organic semiconductor interfaces; (3) used displacement current measurement (DCM) to study charge transport at organic/dielectric interfaces and charge injection at metal/organic interfaces.

Zhu, Xiaoyang; Frisbie, C Daniel

2012-08-13T23:59:59.000Z

Note: This page contains sample records for the topic "magnetic field charged" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Enhancement of accelerating field of microwave cavities by magnetic insulation  

SciTech Connect

Limitations on the maximum achievable accelerating gradient of microwave cavities can strongly influence the performance, length, and cost of particle accelerators. Gradient limitations are widely believed to be initiated by electron emission from the cavity surfaces. Here, we show that the deleterious effects of field emission are effectively suppressed by applying a tangential magnetic field to the cavity walls. With the aid of numerical simulations we compute the field strength required to insulate an 805 MHz cavity and estimate the cavity's tolerances to typical experimental errors such as magnet misalignments and positioning errors. Then, we review an experimental program, currently under progress, to further study the concept. Finally, we report on two specific examples that illustrate the feasibility of magnetic insulation into prospective particle accelerator applications.

Stratakis, D.; Gallardo, J.; Palmer, R.B.

2011-04-15T23:59:59.000Z

422

Magnetic Fields in Gamma-Ray Bursts: A Short Review  

E-Print Network (OSTI)

Magnetic fields play a crucial role in the physics of Gamma-Ray Bursts (GRBs). Strong observational evidence indicates that the observed afterglow and most likely the prompt emission arise from synchrotron emission. It is possible that Poynting flux plays an important or even dominant role in the relativistic outflow from the inner engine, but like in other astronomical relativistic jets this suggestion is controversial. Finally, it is likely that magnetic fields larger than $10^{15}$ G occur within GRBs' inner engines and contribute to the acceleration and collimation of the relativistic jets. I review here the GRB fireball model and discuss the role that magnetic fields play in its various components. I suggest that the early afterglow, that reflects the initial interaction of the relativistic jet with its surrounding matter is the best available tool to explore the nature of relativistic outflow in astronomical relativistic jets.

Tsvi Piran

2005-03-02T23:59:59.000Z

423

Rotational and magnetic field instabilities in neutron stars  

SciTech Connect

In this short review we present recent results on the dynamics of neutron stars and their magnetic fields. We discuss the progress that has been made, during the last 5 years, in understanding the rotational instabilities with emphasis to the one due to the f-mode, the possibility of using gravitational wave detection in constraining the parameters of neutron stars and revealing the equation of state as well as the detectability of gravitational waves produced during the unstable phase of a neutron star’s life. In addition we discuss the dynamics of extremely strong magnetic fields observed in a class of neutron stars (magnetars). Magnetic fields of that strength are responsible for highly energetic phenomena (giant flares) and we demonstrate that the analysis of the emitted electromagnetic radiation can lead in constraining the parameters of neutron stars. Furthermore, we present our results from the study of such violent phenomena in association with the emission of gravitational radiation.

Kokkotas, Kostas D. [Theoretical Astrophysics, IAAT, Eberhard Karls University of Tübingen, Tübingen 72076 (Germany)

2014-01-14T23:59:59.000Z

424

Electric and magnetic field exposure associated with electric blankets  

SciTech Connect

electric blankets may be important contributors to the public's overall exposure to 60 Hz electric and magnetic fields (EMFs) since they are common appliances that are used close to the body for long periods of time. This report describes a series of experimental and computer analyses characterizing various aspects of EMF exposure from electric blankets in use prior to Fall 1990. Almost of electric blankets were found to use on/off controllers with cycle periods of minutes. Calculations of magnetic fields within the body show that, when blankets are heating, flux densities averaged over the whole body range from 15--33 mG during the on'' cycle with typical values of 22 mG. Duty cycles are predicted to vary widely from user-to-user, with typical values of perhaps 40%. Given typical blanket usage patterns, the long-term body-averaged magnetic field exposure from blankets is expected to be comparable to that form other EMF sources for a significant fraction of the blanket-using population. No significant differences were found between time-averaged magnetic field exposures from blankets with metal alloy and plastic polymer heating elements. Blankets with alloy and polymer heating elements did differ significantly in electric field exposure. Calculations show that the unperturbed field 5 cm above flat blankets range from 60--150 V/m for alloy heating cables and unperturbed field 5 cm above flat blankets range from 60--150 V/m for alloy heating cables and 10--40 V/m polymer cables. Starting in Fall 1990, electric blanket manufactures introduced new designs that produce much smaller magnetic fields. These are expected to replace the current in-use stock at a rate of 10--15% per year.

Florig, H.K.; Hoburg, J.F. (Carnegie-Mellon Univ., Pittsburgh, PA (United States). Dept. of Engineering and Public Policy)

1991-12-01T23:59:59.000Z

425

The sediment of mixtures of charged colloids: segregation and inhomogeneous electric fields  

E-Print Network (OSTI)

We theoretically study sedimentation-diffusion equilibrium of dilute binary, ternary, and polydisperse mixtures of colloidal particles with different buoyant masses and/or charges. We focus on the low-salt regime, where the entropy of the screening ions drives spontaneous charge separation and the formation of an inhomogeneous macroscopic electric field. The resulting electric force lifts the colloids against gravity, yielding highly nonbarometric and even nonmonotonic colloidal density profiles. The most profound effect is the phenomenon of segregation into layers of colloids with equal mass-per-charge, including the possibility that heavy colloidal species float onto lighter ones.

Jos Zwanikken; rene van Roij

2005-04-18T23:59:59.000Z

426

Utilizing Nitrogen Vacancy Centers to measure oscillating magnetic fields  

E-Print Network (OSTI)

We show how nitrogen vacancy (NV) centers can be used to determine the amplitude, phase and frequency of unknown weak monochromatic and multichromatic oscillating magnetic fields using only the periodic dynamical decoupling (PDD) and Carr-Purcell-Meiboom-Gill (CPMG) sequences. The effect of decoherence on the measurement of the magnetic field parameters is explicitly analyzed, and we take into account the fact that different pulse sequences suppress decoherence to different extents. Since the sensitivity increases with increasing sensing time while it decreases due to decoherence, we use the Fisher information matrix in order to optimize the number of pulses that should be used.

Adam Zaman Chaudhry

2014-04-11T23:59:59.000Z

427

Electric and Magnetic Fields (EMF) RAPID Engineering Program, Project 7: Development of Field Exposure Models  

SciTech Connect

The purpose of this project was to develop a conceptual model for estimating magnetic field (EMF) personal exposure (PE) of individuals or groups and construct a working model using existing data.

Bracken, T.D.; Rankin, R.F.; Wiley, J.A.

1999-05-01T23:59:59.000Z

428

Determining the exchange parameters of spin-1 metal-organic molecular magnets in pulsed magnetic fields  

SciTech Connect

We nave measured the high-field magnetization of a number of Ni-based metal-organic molecular magnets. These materials are self-assembly coordination polymers formed from transition metal ions and organic ligands. The chemistry of the compounds is versatile allowing many structures with different magnetic properties to be formed. These studies follow on from previous measurements of the Cu-based analogues in which we showed it was possible to extract the exchange parameters of low-dimensional magnets using pulsed magnetic fields. In our recent experiments we have investigated the compound (Ni(HF{sub 2})(pyz){sub 2})PF{sub 6}, where pyz = pyrazine, and the Ni-ions are linked in a quasi-two-dimensional (Q2D) square lattice via the pyrazine molecules, with the layers held together by HF{sub 2} ligands. We also investigated Ni(NCS){sub 2}(pyzdo){sub 2}, where pyzdo = pyrazine dioxide. The samples are grown at Eastern Washington University using techniques described elsewhere. Measurements are performed at the pulsed magnetic field laboratory in Los Alamos. The magnetization of powdered samples is determined using a compensated coil magnetometer in a 65 T short pulse magnet. Temperatures as low as 500 mK are achievable using a {sup 3}He cryostat. The main figure shows the magnetization of the spin-1 [Ni(HF{sub 2})(pyz){sub 2}]PF{sub 6} compound at 1.43 K. The magnetization rises slowly at first, achieving a rounded saturation whose midpoint is around 19 T. A small anomaly is also seen in the susceptibility at low fields ({approx}3 T), which might be attributed to a spin-flop transition. In contrast, the spin-1/2 [Cu(HF{sub 2})(pyz){sub 2}]PF{sub 6} measured previously has a saturation magnetization of 35.5 T and a strongly concave form of M(B) below this field. This latter compound was shown to be a good example of a Q2D Heisenberg antiferromagnet with the strong exchange coupling (J{sub 2D} = 12.4 K, J{sub {perpendicular}}/J{sub 2D} {approx} 10{sup -2}) directed along the Cu-pyz-Cu directions. The structure of the two compounds is similar, but in the case of the Cu-compound the Cu-Cu pathways are linear, whereas in the Ni-compound they are kinked. The pulsed-field data combined with information from temperature-dependent susceptibility, muon-spin rotation, electron-spin resonance and ligand-field calculations suggest that, far from being magnetically Q2D, the Ni-compound is fairly one-dimensional with the dominant exchange (J{sub 1D} = 3.1 K and J{sub {perpendicular}}/J{sub 1D} = 0.63) directed along the Ni-FHF-Ni direction. Ni(NCS){sub 2}(pyzdo){sub 2} was also investigated. Previous ultra-high field measurements using the 100 T magnet have shown that this compound has a saturation field close to 80 T. The purpose of the present studies is to map out the phase diagram of this material at mid-range fields. The data are shown in the inset to the figure. This continuing project probes the ability of organic ligands to mediate magnetic exchange, the link between structure, dimensionality and bulk magnetic properties, as well as the role of spin number in quantum magnets. Ultimately the investigations aim to determine to what extent it is possible to produce self-assembly molecular materials with tailor-made magnetic characteristics.

Mcdonald, Ross D [Los Alamos National Laboratory; Singleton, John [Los Alamos National Laboratory; Lancaster, Tom [OXFORD UNIV.; Goddard, Paul [OXFORD UNIV.; Manson, Jamie [EASTERN WASHINGTON UNIV.

2011-01-14T23:59:59.000Z

429

An IMAGE Satellite Guide to Exploring the Earth's Magnetic Field 1 An IMAGE Satellite Guide to Exploring the Earth's Magnetic Field 2  

E-Print Network (OSTI)

observed by the IMAGE, HENA instrument. Some representative magnetic field lines are shown in whiteAn IMAGE Satellite Guide to Exploring the Earth's Magnetic Field 1 #12;An IMAGE Satellite Guide to Exploring the Earth's Magnetic Field 2 Dr. James Burch IMAGE Principal Investigator Dr. William Taylor Dr

430

Spin Asymmetries Arising In Neutrino-Lepton Processes In A Magnetic Field And Their Macroscopic Appearance  

SciTech Connect

We present expressions that determine the differential cross sections and energy and momentum losses for the neutrino-lepton processes {nu}le- {yields} {nu}le-, {nu}-tildele- {yields} {nu}-tildele-, {nu}l{nu}-tildel {yields} e-e+, {nu}l{nu}-tildee {yields} l-e+, {nu}le- {yields} {nu}el- in a magnetic field with allowance for the longitudinal and transverse polarizations of the charged leptons and antileptons and the results on the spin asymmetries arising in these processes.

Huseynov, Vali A. [Department of General and Theoretical Physics, Nakhchivan State University, AZ 7000, Nakhchivan (Azerbaijan); Laboratory of Physical Research, Nakhchivan Division of Azerbaijan National Academy of Sciences, AZ 7000, Nakhchivan (Azerbaijan); Gasimova, Rasmiyya E.; Akbarova, Nurida Y.; Hajiyeva, Billura T. [Department of General and Theoretical Physics, Nakhchivan State University, AZ 7000, Nakhchivan (Azerbaijan)

2007-06-13T23:59:59.000Z

431

On collisional diffusion in a stochastic magnetic field  

SciTech Connect

The effect of particle collisions on the transport in a stochastic magnetic field in tokamaks is investigated. The model of resonant magnetic perturbations generated by external coils at the plasma edge is used for the stochastic magnetic field. The particle collisions are simulated by a random walk process along the magnetic field lines and the jumps across the field lines at the collision instants. The dependencies of the local diffusion coefficients on the mean free path ?{sub mfp}, the diffusion coefficients of field lines D{sub FL}, and the collisional diffusion coefficients, ?{sub ?} are studied. Based on these numerical data and the heuristic arguments, the empirical formula, D{sub r}=?{sub ?}+v{sub ||}D{sub FL}/(1+L{sub c}/?{sub mfp}), for the local diffusion coefficient is proposed, where L{sub c} is the characteristic length of order of the connection length l{sub c}=?qR{sub 0}, q is the safety factor, R{sub 0} is the major radius. The formula quite well describes the results of numerical simulations. In the limiting cases, the formula describes the Rechester-Rosenbluth and Laval scalings.

Abdullaev, S. S. [Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung - Plasmaphysik, EURATOM Association, 52425 Jülich (Germany)] [Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung - Plasmaphysik, EURATOM Association, 52425 Jülich (Germany)

2013-08-15T23:59:59.000Z

432

Strongest non-destructive magnetic field: world record set at 100-tesla  

NLE Websites -- All DOE Office Websites (Extended Search)

Strongest non-destructive magnetic field: world record set at Strongest non-destructive magnetic field: world record set at 100-tesla level Strongest non-destructive magnetic field: world record set at 100-tesla level National High Magnetic Field Laboratory magnet achieved a whopping 100.75 tesla-the 100-tesla level is roughly equivalent to 2 million times Earth's magnetic field. March 22, 2012 World record set at National High Magnetic Field Laboratory, Los Alamos In 2011, researchers at the National High Magnetic Field Laboratory set a new world record for the strongest nondestructive magnet field: 97.4 tesla. The feat positioned them to in March 2012 deliver a magnet capable of achieving the elusive 100-tesla goal, profoundly affecting a range of scientific investigations. Get Expertise Director, Pulsed Field Facility

433

Self-field effects on instability of wave modes in a two-stream free-electron laser with an axial magnetic field  

SciTech Connect

Free electron lasers (FEL) play major roles in the Raman Regime, due to the charge and current densities of the beam self-field. The method of perturbation has been applied to study the influence of self-electric and self-magnetic fields. A dispersion relation for two-stream free electron lasers with a helical wiggler and an axial magnetic field has been found. This dispersion relation is solved numerically to investigate the influence of self-fields on the FEL coupling and the two-stream instability. It was found that self-fields can produce very large effects on the FEL coupling, but they have almost negligible effects on two-stream instability.

Mohsenpour, Taghi, E-mail: mohsenpour@umz.ac.ir; Rezaee Rami, Omme Kolsoum [Department of Physics, Faculty of Basic Sciences, University of Mazandaran, Babolsar (Iran, Islamic Republic of)

2014-07-15T23:59:59.000Z

434

Magnetic Field Control of the Quantum Chaotic Dynamics of Hydrogen Analogues in an Anisotropic Crystal Field  

E-Print Network (OSTI)

We report magnetic field control of the quantum chaotic dynamics of hydrogen analogues in an anisotropic solid state environment. The chaoticity of the system dynamics was quantified by means of energy level statistics. We analyzed the magnetic field dependence of the statistical distribution of the impurity energy levels and found a smooth transition between the Poisson limit and the Wigner limit, i.e. transition between regular Poisson and fully chaotic Wigner dynamics. Effect of the crystal field anisotropy on the quantum chaotic dynamics, which manifests itself in characteristic transitions between regularity and chaos for different field orientations, was demonstrated.

Weihang Zhou; Zhanghai Chen; Bo Zhang; C. H. Yu; Wei Lu; S. C. Shen

2010-03-09T23:59:59.000Z

435

Ultra-low field nuclear magnetic resonance and magnetic resonance imaging to discriminate and identify materials  

DOE Patents (OSTI)

An ultra-low magnetic field NMR system can non-invasively examine containers. Database matching techniques can then identify hazardous materials within the containers. Ultra-low field NMR systems are ideal for this purpose because they do not require large powerful magnets and because they can examine materials enclosed in conductive shells such as lead shells. The NMR examination technique can be combined with ultra-low field NMR imaging, where an NMR image is obtained and analyzed to identify target volumes. Spatial sensitivity encoding can also be used to identify target volumes. After the target volumes are identified the NMR measurement technique can be used to identify their contents.

Kraus, Robert H. (Los Alamos, NM); Matlashov, Andrei N. (Los Alamos, NM); Espy, Michelle A. (Los Alamos, NM); Volegov, Petr L. (Los Alamos, NM)

2010-03-30T23:59:59.000Z

436

Heat pulse propagation in chaotic 3-dimensional magnetic fields  

E-Print Network (OSTI)

Heat pulse propagation in $3$-D chaotic magnetic fields is studied by solving the parallel heat transport equation using a Lagrangian-Green's function (LG) method. The LG method provides an efficient and accurate technique that circumvents limitations of finite elements and finite difference methods. The main two problems addressed are: (i) The dependence of the radial transport on the magnetic field stochasticity (controlled by the amplitude of the perturbation, $\\epsilon$); and (ii) The role of reversed shear configurations on pulse propagation. In all the cases considered there are no magnetic flux surfaces. However, radial transport is observed to depend strongly on $\\epsilon$ due to the presence of high-order magnetic islands and Cantori that act as quasi-transport barriers that preclude the radial penetration of heat pulses within physically relevant time scale. The dependence of the magnetic field connection length, $\\ell_B$, on $\\epsilon$ is studied in detail. The decay rate of the temperature maximum, $\\langle T \\rangle_{max}(t)$, the time delay of the temperature response as function of the radius, $\\tau$, and the radial heat flux $\\langle {{\\bf q}\\cdot {\\hat e}_\\psi} \\rangle$, are also studied as functions of the magnetic field stochasticity and $\\ell_B$. In all cases, the scaling of $\\langle T \\rangle_{max}$ with $t$ transitions from sub-diffusive, $\\langle T \\rangle_{max} \\sim t^{-1/4}$, at short times ($\\chi_\\parallel t 10^5$). A strong dependence on $\\epsilon$ is also observed on $\\tau$ and $\\langle {{\\bf q}\\cdot {\\hat e}_\\psi} \\rangle$. The radial propagation of pulses in fully chaotic fields considerably slows down in the shear reversal region and, as a result, $\\tau$, in reversed shear configurations is an order of magnitude longer than the one in monotonic $q$-profiles.

D. del-Castillo-Negrete; D. Blazevski

2014-09-10T23:59:59.000Z

437

Kinetic models of current sheets with a sheared magnetic field  

SciTech Connect

Thin current sheets, whose existence in the Earth's magnetotail is confirmed by numerous spacecraft measurements, are studied analytically and numerically. The thickness of such sheets is on the order of the ion Larmor radius, and the normal component of the magnetic field (B{sub z}) in the sheet is almost constant, while the tangential (B{sub x}) and shear (B{sub y}) components depend on the transverse coordinate z. The current density in the sheet also has two self-consistent components (j{sub x} and j{sub y}, respectively), and the magnetic field lines are deformed and do not lie in a single plane. To study such quasi-one-dimensional current configurations, two kinetic models are used, in particular, a numerical model based on the particle-in-cell method and an analytical model. The calculated results show that two different modes of the self-consistent shear magnetic field B{sub y} and, accordingly, two thin current sheet configurations can exist for the same input parameters. For the mode with an antisymmetric z profile of the B{sub y} component, the magnetic field lines within the sheet are twisted, whereas the profiles of the plasma density, current density component j{sub y}, and magnetic field component B{sub x} differ slightly from those in the case of a shearless magnetic field (B{sub y} = 0). For the symmetric B{sub y} mode, the magnetic field lines lie in a curved surface. In this case, the plasma density in the sheet varies slightly and the current sheet is two times thicker. Analysis of the dependence of the current sheet structure on the flow anisotropy shows that the sheet thickness decreases significantly with decreasing ratio between the thermal and drift plasma velocities, which is caused by the dynamics of quasi-adiabatic ions. It is shown that the results of the analytical and numerical models are in good agreement. The problems of application of these models to describe current sheets at the magnetopause and near magnetic reconnection regions are discussed.

Mingalev, O. V.; Mingalev, I. V.; Mel'nik, M. N. [Russian Academy of Sciences, Polar Geophysical Institute, Cola Science Center (Russian Federation); Artemyev, A. V.; Malova, H. V.; Popov, V. Yu. [Russian Academy of Sciences, Space Research Institute (Russian Federation); Chao, Shen [Chinese Academy of Sciences, Center for Space Science and Applied Research (China); Zelenyi, L. M. [Russian Academy of Sciences, Space Research Institute (Russian Federation)

2012-04-15T23:59:59.000Z

438

National High Magnetic Field Laboratory Audio Dictionary: Resistive...  

NLE Websites -- All DOE Office Websites (Extended Search)

and Flash to stream the Magnet Minute Mark Bird Associated Links Making Magnets (audio slideshow) Making Resistive Magnets (article) Meet the Magnets Magnet Science &...

439

Magnetic Field Created by Tile Permanent R. Ravaud, G. Lemarquand, V. Lemarquand  

E-Print Network (OSTI)

1 Magnetic Field Created by Tile Permanent Magnets R. Ravaud, G. Lemarquand, V. Lemarquand Abstract1 This paper presents the analytical calculation of the three components of the magnetic field created by2 tile permanent magnets whose magnetization is either radial or axial. The calculations

Boyer, Edmond

440

Crystal-Field Splitting and Giant Negative Magnetization in  

SciTech Connect

Bimetallic oxalates are a class of layered organic magnets with transi- tion metals M(II) and M'(III) coupled by oxalate molecules in an open honeycomb structure. Of particular interest are the Fe(II)Fe(III) bimetal- lic compounds, which are ferrimagnetically ordered below a transition temperature that ranges from 30 to 48 K, depending on the cation that separates the layers. In small magnetic fields, several of these compounds exhibit giant negative magnetization below a compensation temperature of roughly 2/3 Tc. By studying the behavior of the Kramer's doublet ground state produced by the crystal-field splitting and constructing a reduced Hamiltonian that includes both exchange and spin-orbit and in- teractions, we can explain all of the important behavior of this class of materials: the stability of magnetic order in two dimensions and the existence of magnetic compensation in samples with high transition tem- peratures. We also provide several new predictions for the spin-wave gap and the optical flipping of the magnetic moment.

Fishman, Randy Scott [ORNL; Reboredo, Fernando A [ORNL

2007-01-01T23:59:59.000Z

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441

MISALIGNMENT OF MAGNETIC FIELDS AND OUTFLOWS IN PROTOSTELLAR CORES  

SciTech Connect

We present results of {lambda}1.3 mm dust-polarization observations toward 16 nearby, low-mass protostars, mapped with {approx}2.''5 resolution at CARMA. The results show that magnetic fields in protostellar cores on scales of {approx}1000 AU are not tightly aligned with outflows from the protostars. Rather, the data are consistent with scenarios where outflows and magnetic fields are preferentially misaligned (perpendicular), or where they are randomly aligned. If one assumes that outflows emerge along the rotation axes of circumstellar disks, and that the outflows have not disrupted the fields in the surrounding material, then our results imply that the disks are not aligned with the fields in the cores from which they formed.

Hull, Charles L. H.; Plambeck, Richard L.; Bower, Geoffrey C.; Heiles, Carl; Meredith Hughes, A. [Astronomy Department and Radio Astronomy Laboratory, University of California, Berkeley, CA 94720-3411 (United States); Bolatto, Alberto D.; Jameson, Katherine; Mundy, Lee; Pound, Marc W. [Astronomy Department and Laboratory for Millimeter-wave Astronomy, University of Maryland, College Park, MD 20742 (United States); Carpenter, John M.; Lamb, James W.; Pillai, Thushara [Department of Astronomy, California Institute of Technology, 1200 E. California Blvd., MC 249-17, Pasadena, CA 91125 (United States); Crutcher, Richard M.; Hakobian, Nicholas S.; Kwon, Woojin; Looney, Leslie W. [Department of Astronomy, University of Illinois at Urbana-Champaign, 1002 W Green Street, Urbana, IL 61801 (United States); Fiege, Jason D.; Franzmann, Erica [Department of Physics and Astronomy, University of Manitoba, Winnipeg, MB R3T 2N2 (Canada); Houde, Martin [Department of Physics and Astronomy, University of Western Ontario, London, ON N6A 3K7 (Canada); Matthews, Brenda C., E-mail: chat@astro.berkeley.edu [Department of Physics and Astronomy, University of Victoria, 3800 Finnerty Rd., Victoria, BC V8P 5C2 (Canada); and others

2013-05-10T23:59:59.000Z

442

Electronic structure of diluted magnetic semiconductor superlattices: In-plane magnetic field effect  

Science Journals Connector (OSTI)

The electronic structure of diluted magnetic semiconductor (DMS) superlattices under an in-plane magnetic field is studied within the framework of the effective-mass theory; the strain effect is also included in the calculation. The numerical results show that an increase of the in-plane magnetic field renders the DMS superlattice from the direct band-gap system to the indirect band-gap system, and spatially separates the electron and the hole by changing the type-I band alignment to a type-II band alignment. The optical transition probability changes from type I to type II and back to type I like at large magnetic field. This phenomenon arises from the interplay among the superlattice potential profile, the external magnetic field, and the sp-d exchange interaction between the carriers and the magnetic ions. The shear strain induces a strong coupling of the light- and heavy-hole states and a transition of the hole ground states from “light”-hole to “heavy”-hole-like states.

Hai-Bin Wu, Kai Chang, and Jian-Bai Xia

2002-04-22T23:59:59.000Z

443

Vortex Structure in Charged Condensate  

E-Print Network (OSTI)

We study magnetic fields in the charged condensate that we have previously argued should be present in helium-core white dwarf stars. We show that below a certain critical value the magnetic field is entirely expelled from the condensate, while for larger values it penetrates the condensate within flux-tubes that are similar to Abrikosov vortex lines; yet higher fields lead to the disruption of the condensate. We find the solution for the vortex lines in both relativistic and nonrelativistic theories that exhibit the charged condensation. We calculate the energy density of the vortex solution and the values of the critical magnetic fields. The minimum magnetic field required for vortices to penetrate the helium white dwarf cores ranges from roughly 10^7 to 10^9 Gauss. Fields of this strength have been observed in white dwarfs. We also calculate the London magnetic field due to the rotation of a dwarf star and show that its value is rather small.

Gabadadze, Gregory

2009-01-01T23:59:59.000Z

444

Vortex Structure in Charged Condensate  

E-Print Network (OSTI)

We study magnetic fields in the charged condensate that we have previously argued should be present in helium-core white dwarf stars. We show that below a certain critical value the magnetic field is entirely expelled from the condensate, while for larger values it penetrates the condensate within flux-tubes that are similar to Abrikosov vortex lines; yet higher fields lead to the disruption of the condensate. We find the solution for the vortex lines in both relativistic and nonrelativistic theories that exhibit the charged condensation. We calculate the energy density of the vortex solution and the values of the critical magnetic fields. The minimum magnetic field required for vortices to penetrate the helium white dwarf cores ranges from roughly 10^7 to 10^9 Gauss. Fields of this strength have been observed in white dwarfs. We also calculate the London magnetic field due to the rotation of a dwarf star and show that its value is rather small.

Gregory Gabadadze; Rachel A. Rosen

2009-05-14T23:59:59.000Z

445

Analytical description for field-line wandering in strong magnetic turbulence  

Science Journals Connector (OSTI)

We investigate analytically the random walk of magnetic field lines. In previous analytical treatments of field line wandering or random walk, it was assumed that the turbulent magnetic field is much weaker than the mean field. In the present paper, we develop an improved analytical method to describe the stochastic properties of turbulent magnetic fields. This approach is an extension of the standard theory of field line wandering and can be applied to weak as well as to strong magnetic turbulence.

A. Shalchi; J. A. le Roux; G. M. Webb; G. P. Zank

2009-12-31T23:59:59.000Z

446

Ferrofluid aggregates phase transitions in the planar magnetic field  

E-Print Network (OSTI)

The influence of the cyclic heating and cooling on properties of the aggregates (aka "ferrofluid clusters") in a ferrofluid, which made on the basis of magnetite nanoparticles, are investigated. The heating of the ferrofluid layer with such aggregates leads to equalization of the concentration between high- and low-concentrated phases. The temperature of the equalization of the phase concentrations was determined at different values of an external constant magnetic field, which was applied parallel to the layer of the ferrofluid. The temperature of the destruction of a periodic structure of the magnetic aggregates, which were formed during cooling of a homogeneous phase of the ferrofluid, was obtained at the different values of the applied external magnetic field.

V. F. Kovalenko; M. V. Petrychuk; B. M. Tanygin; S. I. Shulyma

2014-04-21T23:59:59.000Z

447

Dynamical constraints from field line topology in magnetic flux tubes  

E-Print Network (OSTI)

A topological constraint on the dynamics of a magnetic field in a flux tube arises from the fixed point indices of its field line mapping. This can explain unexpected behaviour in recent resistive-magnetohydrodynamic simulations of magnetic relaxation. Here we present the theory for a general periodic flux tube, representing, for example, a toroidal confinement device or a solar coronal loop. We show how an ideal dynamics on the side boundary of the tube implies that the sum of indices over all interior fixed points is invariant. This constraint applies to any continuous evolution inside the tube, which may be turbulent and/or dissipative. We also consider the analogous invariants obtained from periodic points (fixed points of the iterated mapping). Although there is a countably infinite family of invariants, we show that they lead to at most two independent dynamical constraints. The second constraint applies only in certain magnetic configurations. Several examples illustrate the theory.

A. R. Yeates; G. Hornig

2011-03-11T23:59:59.000Z

448

MAGNETIC FIELDS AND THE OUTER ROTATION CURVE OF M31  

SciTech Connect

Recent observations of the rotation curve of M31 show a rise of the outer part that cannot be understood in terms of standard dark matter models or perturbations of the galactic disk by M31's satellites. Here, we propose an explanation of this dynamical feature based on the influence of the magnetic field within the thin disk. We have considered standard mass models for the luminous mass distribution, a Navarro-Frenk-White model to describe the dark halo, and we have added up the contribution to the rotation curve of a magnetic field in the disk, which is described by an axisymmetric pattern. Our conclusion is that a significant improvement of the fit in the outer part is obtained when magnetic effects are considered. The best-fit solution requires an amplitude of {approx}4 {mu}G with a weak radial dependence between 10 and 38 kpc.

Ruiz-Granados, B.; Rubino-Martin, J. A. [Instituto de Astrofisica de Canarias (IAC), E-38200, La Laguna, Tenerife (Spain); Florido, E.; Battaner, E. [Departamento Fisica Teorica y del Cosmos, Universidad de Granada, Granada (Spain)

2010-11-01T23:59:59.000Z

449

What is a flux tube? On the magnetic field topology of buoyant flux structures  

E-Print Network (OSTI)

study the topology of field lines threading buoyant magnetic flux struc- tures. The magnetic structures on the parameters, the system exhibits varying degrees of symmetry. By integrating along magnetic field lines of the evolution, and therefore the degree of symmetry, the resulting magnetic structures can have field lines

450

The CP2 star ff 2 CVn: radial velocity, magnetic field,  

E-Print Network (OSTI)

with the areas of the magnetic poles (in case of Cr) as with the regions where the magnetic field lines haveThe CP2 star ff 2 CVn: radial velocity, magnetic field, and element distribution G. Hildebrandt­ metric observations made in Tautenburg the radial velocity and the strength of the magnetic field

451

POSSIBLE EVIDENCE FOR A FISK-TYPE HELIOSPHERIC MAGNETIC FIELD. I. ANALYZING ULYSSES/KET ELECTRON OBSERVATIONS  

SciTech Connect

The propagation of energetic charged particles in the heliospheric magnetic field is one of the fundamental problems in heliophysics. In particular, the structure of the heliospheric magnetic field remains an unsolved problem and is discussed as a controversial topic. The first successful analytic approach to the structure of the heliospheric magnetic field was the Parker field. However, the measurements of the Ulysses spacecraft at high latitudes revealed the possible need for refinements of the existing magnetic field model during solar minimum. Among other reasons, this led to the development of the Fisk field. This approach is highly debated and could not be ruled out with magnetic field measurements so far. A promising method to trace this magnetic field structure is to model the propagation of electrons in the energy range of a few MeV. Employing three-dimensional and time-dependent simulations of the propagation of energetic electrons, this work shows that the influence of a Fisk-type field on the particle transport in the heliosphere leads to characteristic variations of the electron intensities on the timescale of a solar rotation. For the first time it is shown that the Ulysses count rates of 2.5-7 MeV electrons contain the imprint of a Fisk-type heliospheric magnetic field structure. From a comparison of simulation results and the Ulysses count rates, realistic parameters for the Fisk theory are derived. Furthermore, these parameters are used to investigate the modeled relative amplitudes of protons and electrons, including the effects of drifts.

Sternal, O.; Heber, B.; Kopp, A. [Institut fuer Experimentelle und Angewandte Physik, Christian-Albrechts-Universitaet zu Kiel, Leibnizstr. 11, 24118 Kiel (Germany); Engelbrecht, N. E.; Burger, R. A.; Ferreira, S. E. S.; Potgieter, M. S. [Center for Space Research, North-West University, 2520 Potchefstroom, South Africa. (South Africa); Fichtner, H.; Scherer, K., E-mail: oliver.sternal@rub.de [Institut fuer Theoretische Physik, Lehrstuhl IV: Weltraum- und Astrophysik, Ruhr-Universitaet Bochum, 44780 Bochum, Germany. (Germany)

2011-11-01T23:59:59.000Z

452

LOW ENERGY ELECTRON TRANSPORT BY RECONNECTED MAGNETIC FIELDS AROUND MARS  

E-Print Network (OSTI)

presents a significant ionospheric obstacle to the solar wind. Moreover, the presence of strong crustalLOW ENERGY ELECTRON TRANSPORT BY RECONNECTED MAGNETIC FIELDS AROUND MARS A DISSERTATION SUBMITTED;Abstract The solar wind interaction with Mars has been studied extensively through satellite observations

453

Observation of conical electron distributions over Martian crustal magnetic fields  

E-Print Network (OSTI)

]. Although the main obstacle to the solar wind is the Martian ionosphere, the strong crustal magnetic fields. The energy spectra of the conics exhibit substantial decreases in all energy levels in relation (draped IMF direction, solar wind pressure, and EUV flux) do not affect the observation of the events

California at Berkeley, University of

454

Visualizing Planetary Magnetic Fields (and Why You Should Care)  

E-Print Network (OSTI)

, Berkeley; 2University of Colorado at Boulder; 3Center of Science Education, Space Sciences Laboratory (CSE@SSL), University of California, Berkeley esea c , Out eac Activities, and Their Impacts II Posters esea c , Out eac Activities, and Their Impacts II Posters Introduction · The magnetic fields of the large terrestrial planets

Fillingim, Matthew

455

Bifurcation of the fmode in presence of nonuniform magnetic field  

E-Print Network (OSTI)

of the bifurcation and plausibly a continuous spectrum of the f � mode in standard k# diagram in our sim� ulations & Heyvaerts (1987) on MHD modes in a periodic magnetic field, but not the f�mode. E#ect of surface ten� sion

Brandenburg, Axel

456

On magnetic fields in broad-line blazars  

E-Print Network (OSTI)

High energy spectra of broad-line blazars can be reproduced by both synchrotron-self-Compton (SSC) models and external-Compton (EC) models. However, as is known from numerical modeling, SSC scenarios require much weaker magnetic field than EC ones. In this paper we quantify these results analytically.

R. Moderski; M. Sikora

2006-12-13T23:59:59.000Z

457

Stiff magnetic field lines. I. A geometrical foundation  

Science Journals Connector (OSTI)

It is shown that the foliation of a space-time manifold of codimension 2 provides a basis for the study of the deformation of magnetic field lines. It is found that the fluid flow ... the curvature vector of a no...

G. Prasad

1981-03-01T23:59:59.000Z

458

Novel Lifshitz point for chiral transition in the magnetic field  

E-Print Network (OSTI)

Based on the generalized Ginzburg-Landau theory, chiral phase transition is discussed in the presence of magnetic field. Considering the chiral density wave we show chiral anomaly gives rise to an inhomogeneous chiral phase for nonzero quark-number chemical potential. Novel Lifshitz point appears on the vanishing chemical potential line, which may be directly explored by the lattice QCD simulation.

T. Tatsumi; K. Nishiyama; S. Karasawa

2014-05-09T23:59:59.000Z

459

On the Magnetic Field of a Rotating Molecule  

Science Journals Connector (OSTI)

The space distribution and magnitude of electronic currents in a rotating molecule with a ?1 ground state are re-examined. An evaluation of the magnetic field set up by the rotation is attempted, and the results are used to interpret the width of radiofrequency resonance lines of some alkali halides.

G. C. Wick

1948-01-01T23:59:59.000Z

460

New approaches to thermoelectric cooling effects in magnetic fields  

SciTech Connect

The authors review thermoelectric effects in a magnetic field at a phenomenological level. Discussions of the limiting performance and problems with its computation for both Peltier and Ettingshausen coolers are presented. New principles are discussed to guide the materials scientist in the search for better Ettingshausen materials, and a brief review of the subtle measurement problems is presented.

Migliori, A.; Darling, T.W.; Freibert, F.; Trugman, S.A.; Moshopoulou, E. [Los Alamos National Lab., NM (United States); Sarrao, J.L. [Florida State Univ., Tallahassee, FL (United States)

1997-08-01T23:59:59.000Z

Note: This page contains sample records for the topic "magnetic field charged" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
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461

Electron Cyclotron Heating in a Non-Uniform Magnetic Field  

E-Print Network (OSTI)

Electron Cyclotron Heating in a Non-Uniform Magnetic Field by J.e. Sprott December 1968 Presented pulse. IN1RODUCTION Most previous theories of electron cyclotron resonance heating have dealt primarily will outline a simple theoretical model which can be used to estimate the electron cyclotron heating rate

Sprott, Julien Clinton

462

Particle accelerator employing transient space charge potentials  

DOE Patents (OSTI)

The invention provides an accelerator for ions and charged particles. The plasma is generated and confined in a magnetic mirror field. The electrons of the plasma are heated to high temperatures. A series of local coils are placed along the axis of the magnetic mirror field. As an ion or particle beam is directed along the axis in sequence the coils are rapidly pulsed creating a space charge to accelerate and focus the beam of ions or charged particles.

Post, Richard F. (Walnut Creek, CA)

1990-01-01T23:59:59.000Z

463

Tunable dynamic response of magnetic gels: impact of structural properties and magnetic fields  

E-Print Network (OSTI)

Ferrogels and magnetic elastomers feature mechanical properties that can be reversibly tuned from outside through magnetic fields. Here we concentrate on the question how their dynamic response can be adjusted. The influence of three factors on the dynamic behavior is demonstrated using appropriate minimal models: first, the orientational memory imprinted into one class of the materials during their synthesis; second, the structural arrangement of the magnetic particles in the materials; and third, the strength of an external magnetic field. To illustrate the latter point, structural data are extracted from a real experimental sample and analyzed. Understanding how internal structural properties and external influences impact the dominant dynamical properties helps to design materials that optimize the requested behavior.

Mitsusuke Tarama; Peet Cremer; Dmitry Y. Borin; Stefan Odenbach; Hartmut Löwen; Andreas M. Menzel

2014-06-26T23:59:59.000Z

464

Far-Infrared Studies of Spin-Peierls Materials in a Magnetic Field  

Science Journals Connector (OSTI)

Both a 20 T superconducting magnet and a 33 T resistive magnet were employed for the magnetic field work. ... Bottom panel:? dashed line, absolute transmission spectra of MEM(TCNQ)2 at 300 K and zero field; solid lines, 5 K transmission ratios of MEM(TCNQ)2 taken as a function of applied magnetic field. ... (47)?Ng, H. K.; Wang, Y. J. Proceedings of the Physical Phenomena at High Magnetic Fields II Conference, Tallahassee, FL, Fisk, Z., Ed.; 1995. ...

G. Li; J. S. Lee; V. C. Long; J. L. Musfeldt; Y. J. Wang; M. Almeida; A. Revcolevschi; G. Dhalenne

1998-03-04T23:59:59.000Z

465

On Space Quantization in Time Varying Magnetic Fields  

Science Journals Connector (OSTI)

The transitions between states of different space quantization which take place when an atom is passed through a weak inhomogeneous magnetic field are calculated by approximate methods taking into account the coupling between the nucleus and the orbital electrons. Two types of field are considered, namely, the field introduced by Majorana and the one introduced by Güttinger. For the Majorana field a discussion of the cases I arbitrary J=12, J arbitrary I=12, and I and J arbitrary with explicit application to the nitrogen atom is given. For the Güttinger field the general equations are set up for a field of any strength and are then applied to the case I=J=12.

Lloyd Motz and M. E. Rose

1936-08-15T23:59:59.000Z

466

MAGNETIC FIELD CONFINEMENT IN THE SOLAR CORONA. II. FIELD-PLASMA INTERACTION B. Fornberg,2  

E-Print Network (OSTI)

MAGNETIC FIELD CONFINEMENT IN THE SOLAR CORONA. II. FIELD-PLASMA INTERACTION N. Flyer,1 B. Fornberg numerically to generate a continuum of solutions with two parameters to control the total azimuthal flux from the study to the solar corona and the energetics of coronal mass ejections and flares. Subject

Fornberg, Bengt

467

Influence of the pulsating electric field on the ECR heating in a nonuniform magnetic field  

SciTech Connect

According to a computer simulation, the randomized pulsating electric field can strongly influence the ECR plasma heating in a nonuniform magnetic field. It has been found out that the electron energy spectrum is shifted to the high energy region. The obtained effect is intended to be used in the ECR sources for effective X-ray generation.

Balmashnov, A. A., E-mail: abalmashnov@sci.pfu.edu.ru; Umnov, A. M. [People's Friendship University of Russia (Russian Federation)

2011-12-15T23:59:59.000Z

468

Phase mixing of upper hybrid oscillations in a cold inhomogeneous plasma placed in an inhomogeneous magnetic field  

SciTech Connect

We study phase mixing/wave breaking phenomena of upper hybrid modes in a cold inhomogeneous plasma placed in an inhomogeneous magnetic field. Inhomogeneities both in the background ion density and magnetic field profile are treated as periodic in space but independent in time. The Lagrangian fluid description is employed to obtain an exact solution of this fully nonlinear problem. It is demonstrated that the upper hybrid modes, excited by an initial local charge imbalance, break via phase mixing, induced by the inhomogeneities. It is also shown that it is possible to avoid phase mixing in excited upper hybrid oscillations in an inhomogeneous plasma containing a finite amplitude ion density fluctuation. The choice of external magnetic field is shown to have a key role in avoiding phase mixing in such oscillations. The relevance of our investigation regarding the particle acceleration in an inhomogeneous plasma has also been discussed.

Sarkar, Anwesa; Maity, Chandan; Chakrabarti, Nikhil [Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700 064 (India)] [Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700 064 (India)

2013-05-15T23:59:59.000Z

469

Development of high temperature superconductors for magnetic field applications  

SciTech Connect

The key requirement for magnetic field applications of high temperature superconductor (HTS) materials is to have conductors with high transport critical current density available for magnet builders. After 3 or 4 years of being without any such object, conductor makers have had recent success in producing simple conductor prototypes. These have permitted the construction of simple HTS magnets having self fields exceeding 1 tesla at 4K. Thus the scientific feasibility of making powerful HTS magnets has been demonstrated. Attention to the technological aspects of making HTS conductors for magnets with strong flux pinning and reduced superconducting granularity is now sensible and attractive. However, extrinsic defects such as filament sausaging, cracking, misaligned grains and other perturbation to long range current flow must be controlled at a low level if the benefit of intrinsic improvements to the critical current density is to be maintained in the conductor form. Due to the great complexity of the HTS materials, there is sometimes confusion as to whether a given sample has an intrinsically or extrinsically limited critical current density. Systematic microstructure variation experiments and resistive transition analysis are shown to be particularly helpful in this phase of conductor development.

Larbalestier, D.C.

1991-01-01T23:59:59.000Z

470

Development of high temperature superconductors for magnetic field applications  

SciTech Connect

The key requirement for magnetic field applications of high temperature superconductor (HTS) materials is to have conductors with high transport critical current density available for magnet builders. After 3 or 4 years of being without any such object, conductor makers have had recent success in producing simple conductor prototypes. These have permitted the construction of simple HTS magnets having self fields exceeding 1 tesla at 4K. Thus the scientific feasibility of making powerful HTS magnets has been demonstrated. Attention to the technological aspects of making HTS conductors for magnets with strong flux pinning and reduced superconducting granularity is now sensible and attractive. However, extrinsic defects such as filament sausaging, cracking, misaligned grains and other perturbation to long range current flow must be controlled at a low level if the benefit of intrinsic improvements to the critical current density is to be maintained in the conductor form. Due to the great complexity of the HTS materials, there is sometimes confusion as to whether a given sample has an intrinsically or extrinsically limited critical current density. Systematic microstructure variation experiments and resistive transition analysis are shown to be particularly helpful in this phase of conductor development.

Larbalestier, D.C.

1991-12-31T23:59:59.000Z

471

LDRD final report on confinement of cluster fusion plasmas with magnetic fields.  

SciTech Connect

Two versions of a current driver for single-turn, single-use 1-cm diameter magnetic field coils have been built and tested at the Sandia National Laboratories for use with cluster fusion experiments at the University of Texas in Austin. These coils are used to provide axial magnetic fields to slow radial loss of electrons from laser-produced deuterium plasmas. Typical peak field strength achievable for the two-capacitor system is 50 T, and 200 T for the ten-capacitor system. Current rise time for both systems is about 1.7 {mu}s, with peak current of 500 kA and 2 MA, respectively. Because the coil must be brought to the laser, the driver needs to be portable and drive currents in vacuum. The drivers are complete but laser-plasma experiments are still in progress. Therefore, in this report, we focus on system design, initial tests, and performance characteristics of the two-capacitor and ten-capacitors systems. The questions of whether a 200 T magnetic field can retard the breakup of a cluster-fusion plasma, and whether this field can enhance neutron production have not yet been answered. However, tools have been developed that will enable producing the magnetic fields needed to answer these questions. These are a two-capacitor, 400-kA system that was delivered to the University of Texas in 2010, and a 2-MA ten-capacitor system delivered this year. The first system allowed initial testing, and the second system will be able to produce the 200 T magnetic fields needed for cluster fusion experiments with a petawatt laser. The prototype 400-kA magnetic field driver system was designed and built to test the design concept for the system, and to verify that a portable driver system could be built that delivers current to a magnetic field coil in vacuum. This system was built copying a design from a fixed-facility, high-field machine at LANL, but made to be portable and to use a Z-machine-like vacuum insulator and vacuum transmission line. This system was sent to the University of Texas in Austin where magnetic fields up to 50 T have been produced in vacuum. Peak charge voltage and current for this system have been 100 kV and 490 kA. It was used this last year to verify injection of deuterium and surrogate clusters into these small, single-turn coils without shorting the coil. Initial test confirmed the need to insulate the inner surface of the coil, which requires that the clusters must be injected through small holes in an insulator. Tests with a low power laser confirmed that it is possible to inject clusters into the magnetic field coils through these holes without destroying the clusters. The university team also learned the necessity of maintaining good vacuum to avoid insulator, transmission line, and coil shorting. A 200-T, 2 MA system was also constructed using the experience from the first design to make the pulsed-power system more robust. This machine is a copy of the prototype design, but with ten 100-kV capacitors versus the two used in the prototype. It has additional inductance in the switch/capacitor unit to avoid breakdown seen in the prototype design. It also has slightly more inductance at the cable connection to the vacuum chamber. With this design we have been able to demonstrate 1 MA current into a 1 cm diameter coil with the vacuum chamber at air pressure. Circuit code simulations, including the additional inductance with the new design, agree well with the measured current at a charge voltage of 40 kV with a short circuit load, and at 50 kV with a coil. The code also predicts that with a charge voltage of 97 kV we will be able to get 2 MA into a 1 cm diameter coil, which will be sufficient for 200 T fields. Smaller diameter or multiple-turn coils will be able to achieve even higher fields, or be able to achieve 200-T fields with lower charge voltage. Work is now proceeding at the university under separate funding to verify operation at the 2-MA level, and to address issues of debris mitigation, measurement of the magnetic field, and operation in vacuum. We anticipate operation at full current with single

Argo, Jeffrey W.; Kellogg, Jeffrey W.; Headley, Daniel Ignacio; Stoltzfus, Brian Scott; Waugh, Caleb J.; Lewis, Sean M.; Porter, John Larry, Jr.; Wisher, Matthew; Struve, Kenneth William; Savage, Mark Edward; Quevedo, Hernan J.; Bengtson, Roger

2011-11-01T23:59:59.000Z

472

Magnetic particles confined in a modulated channel: structural transitions tunable by tilting a magnetic field  

E-Print Network (OSTI)

The ground state of colloidal magnetic particles in a modulated channel are investigated as function of the tilt angle of an applied magnetic field. The particles are confined by a parabolic potential in the transversal direction while in the axial direction a periodic substrate potential is present. By using Monte Carlo (MC) simulations, we construct a phase diagram for the different crystal structures as a function of the magnetic field orientation, strength of the modulated potential and the commensurability factor of the system. Interestingly, we found first and second order phase transitions between different crystal structures, which can be manipulated by the orientation of the external magnetic field. A re-entrant behavior is found between two- and four-chain configurations, with continuous second order transitions. Novel configurations are found consisting of frozen in solitons. By changing the orientation and/or strength of the magnetic field and/or the strength and the spatial frequency of the periodic substrate potential, the system transits through different phases.

J. E. Galván-Moya; D. Lucena; W. P. Ferreira; F. M. Peeters

2014-01-03T23:59:59.000Z

473

Magnetic field calculations for iron oxide nanoparticles for MRI  

Science Journals Connector (OSTI)

The susceptibility effects of superparamagnetic iron oxide nanoparticles (SPIONs) functionalized with triethylenglycol (TREG) and Polyethylen Glycol (PEG) has been studied those nanoparticles have the necessary properties to be used in the clinic as contrast media in imaging by MRI[1–3]. We are considering the behavior of the magnetic field as plane wave to explain the electrical and magnetic field produced by SPIONs. Images were acquired on a 1.5T imager Philips using mFFE Sequence. Three glass capillary tubes with a) TREG (10nm) concentration of 300 ?g/ml and PEGCOOH 6000(10nm) with 300 ?g/ml and 2% agarosa. Magnetic field simulations were calculated in Matlab. The plane wave that comes in contact with a sphere of radius a an propagation constant k1 and it is in an homogeneous space k2. We consider that the electric field is linearly polarized on x-direction with a propagation on z-positive-axis. The secondary induced field can be explained from the interior of the sphere and valid exterior points. The referred waves are transmitted and reflected this is valid only when the wavelength is smaller than the radius of the sphere. The obtained vibrational mode is an answer of the electrical oscillation and this is projection of the disturbed magnetic field. TREG-SPIONs produce more serious susceptibility artefacts compared to PEG-SPIONs. This study is promissory due to the concordance of the results of the simulations and the inhomogeneities showed in the MR images.

2014-01-01T23:59:59.000Z

474

THE MAGNETIC CONFINEMENT OF ELECTRON AND PHOTON DOSE PROFILES AND THE POSSIBLE EFFECT OF THE MAGNETIC FIELD ON  

E-Print Network (OSTI)

THE MAGNETIC CONFINEMENT OF ELECTRON AND PHOTON DOSE PROFILES AND THE POSSIBLE EFFECT OF THE MAGNETIC FIELD ON RELATIVE BIOLOGICAL EFFECTIVENESS by Yu Chen A dissertation submitted in partial magnetic field can significantly improve electron beam dose profiles. This could permit improved targeting

Becchetti, Fred

475

Proto-Neutron Star Winds with Magnetic Fields and Rotation  

E-Print Network (OSTI)

We solve the 1D neutrino-heated non-relativistic MHD wind problem for conditions that range from slowly rotating (spin period P > 10 ms) protoneutron stars (PNSs) with surface field strengths typical of radio pulsars (B winds are relativistic. We then quantify the effects of rotation and magnetic fields on the mass loss, energy loss, and r-process nucleosynthesis in PNS winds. We describe the evolution of PNS winds through the Kelvin-Helmholtz cooling epoch, emphasizing the transition between (1) thermal neutrino-driven, (2) non-relativistic magnetically-dominated, and (3) relativistic magnetically-dominated outflows. We find that proto-magnetars with P ~ 1 ms and B > 10^15 G drive relativistic winds with luminosities, energies, and Lorentz factors (magnetization sigma ~ 0.1-1000) consistent with those required to produce long duration gamma-ray bursts and hyper-energetic supernovae (SNe). A significant fraction of the rotational energy may be extracted in only a few seconds, sufficiently rapidly to alter the asymptotic energy of the SN remnant, its morphology, and, potentially, its nucleosynthetic yield. Winds from PNSs with more modest rotation periods (2 - 10 ms) and with magnetar-strength fields produce conditions significantly more favorable for the r-process than winds from slowly rotating PNSs. Lastly, we show that energy and momentum deposition by convectively-excited waves further increase the likelihood of successful r-process in PNS winds.

Brian D. Metzger; Todd A. Thompson; Eliot Quataert

2006-08-30T23:59:59.000Z

476

Crystal Fields and the Effective-Point-Charge Model in the Rare-Earth Pnictides  

Science Journals Connector (OSTI)

Neutron scattering and specific-heat studies of the crystal fields in the rare-earth monophosphides are reported. It is found that the fourth-order crystal-field parameters for the phosphides and for other rare-earth pnictides fall on a universal curve which is close to that predicted by an effective-point-charge model for the light rare earths but deviates markedly for the heavy rare earths.

R. J. Birgeneau; E. Bucher; J. P. Maita; L. Passell; K. C. Turberfield

1973-12-15T23:59:59.000Z

477

A Calculation on the Self-field of a Point Charge and the Unruh Effect  

E-Print Network (OSTI)

Within the context of quantum field theory in curved spacetimes, Hacyan and Sarmiento defined the vacuum stress-energy tensor with respect to the accelerated observer. They calculated it for uniform acceleration and circular motion, and derived that the rotating observer perceives a flux. Mane related the flux to synchrotron radiation. In order to investigate the relation between the vacuum stress and bremsstrahlung, we estimate the stress-energy tensor of the electromagnetic field generated by a point charge, at the position of the charge. We use the retarded field as a self-field of the point charge. Therefore the tensor diverges if we evaluate it as it is. Hence we remove the divergent contributions by using the expansion of the tensor in powers of the distance from the point charge. Finally, we take an average for the angular dependence of the expansion. We calculate it for the case of uniform acceleration and circular motion, and it is found that the order of the vacuum stress multiplied by $\\pi\\alpha$ ($\\alpha=e^2/\\hbar c$ is the fine structure constant) is equal to that of the self-stress. In the Appendix, we give another trial approach with a similar result.

T. Hirayama; T. Hara

2000-07-24T23:59:59.000Z

478

Noninvasive valve monitor using constant magnetic and/or DC electromagnetic field  

DOE Patents (OSTI)

One or more sources of steady magnetic field are carefully located on the outside of a valve body. The constant magnetic field is transmitted into the valve body and valve internals. A magnetic field detector carefully located on the outside of the valve body detects the intensity of the magnetic field at its location. As the position of a valve internal part is changed, there is an alteration in the magnetic field in the valve, and a consequent change in the detected magnetic field. Changes in the detected signal provide an indication of the position and motion of the valve internals.

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

1993-08-17T23:59:59.000Z

479

Resistive stability of magnetic dipole and other axisymmetric closed field line configurations  

E-Print Network (OSTI)

Resistive stability of magnetic dipole and other axisymmetric closed field line configurations by axisymmetric closed line poloidal magnetic fields are common both in nature (examples are stellar and planetary stability is provided by favorable average magnetic field line curvature, many of the closed field line

480

EHLJPSJY---30/Aug/92 ASYMPTOTICS OF HEAVY ATOMS IN HIGH MAGNETIC FIELDS  

E-Print Network (OSTI)

stronger [1]. This field results, presumably, from the trapping of magnetic field lines duringEHLJPSJY---30/Aug/92 ASYMPTOTICS OF HEAVY ATOMS IN HIGH MAGNETIC FIELDS: I. LOWEST LANDAU BAND in a magnetic field B is evaluated exactly to leading order as Z ! 1. In this and a companion work [28] we show

Note: This page contains sample records for the topic "magnetic field charged" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.