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Note: This page contains sample records for the topic "high magnetic fields" 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

High Field Magnetic Resonance Facility  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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

2

High Field Magnet R&D |Superconducting Magnet Division  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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

3

National High Magnetic Field Laboratory - Publications  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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...

4

National High Magnetic Field Laboratory: Superconductors  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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,...

5

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

6

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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...

7

High Pressure Research Questionnaire National High Magnetic Field...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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

8

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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

9

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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,...

10

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

11

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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...

12

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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,...

13

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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...

14

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

15

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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...

16

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

17

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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...

18

National High Magnetic Field Laboratory - Electron Interaction...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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...

19

National High Magnetic Field Laboratory: Superconducting Wire  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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...

20

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

Note: This page contains sample records for the topic "high magnetic fields" 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

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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...

22

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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...

23

Gregory S. Boebinger, National High Magnetic Field Laboratory  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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...

24

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...

25

Magnetic Field Safety Training  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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...

26

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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...

27

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

28

Polarized neutron reflectometry in high magnetic fields  

SciTech Connect (OSTI)

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

29

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.

30

National High Magnetic Field Laboratory: DC Field Facility: High...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

phase transitions High-resolution electron spin resonance (ESR) spectroscopy of transition metal ions (which is of great importance in chemistry, biochemistry and structural...

31

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

32

National High Magnetic Field Laboratory - High B/T Program  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

of experiments where needed. Instrumentation is available for studies of: Dillution refrigerator at the High BT Facility Equipment at the High BT Facility. magnetization...

33

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

34

Mitigated-force carriage for high magnetic field environments  

SciTech Connect (OSTI)

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

35

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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...

36

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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...

37

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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...

38

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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

39

Advanced measurements and techniques in high magnetic fields  

SciTech Connect (OSTI)

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

40

National High Magnetic Field Laboratory - Mission  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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

Note: This page contains sample records for the topic "high magnetic fields" 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 - Flux: Volume 3, Issue...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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......

42

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

43

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

44

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

45

National High Magnetic Field Laboratory - Basic Science  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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...

46

Materials Physics Applications: The National High Magnetic Field Laboratory  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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.

47

National High Magnetic Field Laboratory - Online Tour  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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...

48

2-3 High Field Magnetic Resonance Facility  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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)

49

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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,...

50

National High Magnetic Field Laboratory: Metallic Superlattices  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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...

51

National High Magnetic Field Laboratory - Applied Superconductivity...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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...

52

High-Temperature Superconducting Cable Testing Gregory S. Boebinger, National High Magnetic Field Laboratory  

E-Print Network [OSTI]

High-Temperature Superconducting Cable Testing Gregory S. Boebinger, National High Magnetic Field-Temperature Superconducting (HTS) Cables are desirable for application in large high-field magnets (>20 T), especially when). Of the three HTS magnet cable concepts emerging, the Conductor On Round Core was the first that was tested

Weston, Ken

53

National High Magnetic Field Laboratory - Scientist Profiles...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

"Spatially resolved electronic structure inside and outside the vortex cores of a high-temperature superconductor", Nature 413, 501-504 (2001). 30. V. F. Mitrovi, E. E....

54

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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:...

55

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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...

56

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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...

57

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

58

National High Magnetic Field Laboratory: Magnetic Thin Films  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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...

59

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

60

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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

Note: This page contains sample records for the topic "high magnetic fields" 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

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

62

Development of high temperature superconductors for magnetic field applications  

SciTech Connect (OSTI)

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

63

Development of high temperature superconductors for magnetic field applications  

SciTech Connect (OSTI)

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

64

High Field Magnet R&D in the USA  

E-Print Network [OSTI]

aI. , "Status of High Temperature Superconductor Magnet R&Dmention High Temperature Superconductor (I-ITS). Though

Gourlay, S.A.

2011-01-01T23:59:59.000Z

65

Voltage spike detection in high field superconducting accelerator magnets  

SciTech Connect (OSTI)

A measurement system for the detection of small magnetic flux changes in superconducting magnets, which are due to either mechanical motion of the conductor or flux jump, has been developed at Fermilab. These flux changes are detected as small amplitude, short duration voltage spikes, which are {approx}15mV in magnitude and lasts for {approx}30 {micro}sec. The detection system combines an analog circuit for the signal conditioning of two coil segments and a fast data acquisition system for digitizing the results, performing threshold detection, and storing the resultant data. The design of the spike detection system along with the modeling results and noise analysis will be presented. Data from tests of high field Nb{sub 3}Sn magnets at currents up to {approx}20KA will also be shown.

Orris, D.F.; Carcagno, R.; Feher, S.; Makulski, A.; Pischalnikov, Y.M.; /Fermilab

2004-12-01T23:59:59.000Z

66

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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...

67

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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,...

68

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

69

MagLab and Japan Join Forces on High-field Magnet Research (August...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

and Japan Join Forces on High-field Magnet Research Posted: August 13, 2014 Contact: David Larbalestier TALLAHASSEE, Fla. - The National High Magnetic Field Laboratory (MagLab) has...

70

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

SciTech Connect (OSTI)

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

71

Development of fast cooling pulsed magnets at the Wuhan National High Magnetic Field Center  

SciTech Connect (OSTI)

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

72

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

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high-tech advances made it possible for manufacturers to produce fully electronic meters with LCD screens Related Electricity & Magnetism Pages Timeline: 1870 1879...

73

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

74

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

75

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

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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...

76

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

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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...

77

National High Magnetic Field Laboratory - Try This at Home  

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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...

78

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

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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,...

79

National High Magnetic Field Laboratory - Making a Compass Activity  

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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...

80

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

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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,...

Note: This page contains sample records for the topic "high magnetic fields" 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

Interaction of magnetic field and magnetic history in high-temperature superconductors  

Science Journals Connector (OSTI)

Yttrium barium copper oxide (YBCO) coated conductors are now the most promising high-temperature superconducting tapes in terms of current capacity and price. One form of these conductors utilizes YBCO films on Ni–W metallic tapes and is being considered for a number of power engineering applications. In these applications the conductor will carry an ac current leading to energy losses which are the focus of significant technical and experimental efforts. Our measurements of the ac losses of YBCO/Ni–W conductors carrying ac currents in applied dc magnetic fields have revealed a complex interaction between the magnetic materials present the geometry of the conductor the ac and dc magnetic fields and the electromagnetic “history” of the sample. The investigation of this interaction is the main subject of this paper.

Francesco Grilli; Stephen P. Ashworth; Leonardo Civale

2007-01-01T23:59:59.000Z

82

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

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and Flash to stream the Magnet Minute Mark Bird Associated Links Making Magnets (audio slideshow) Making Resistive Magnets (article) Meet the Magnets Magnet Science &...

83

On-chip SQUID measurements in the presence of high magnetic fields...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

NANOTECHNOLOGY Nanotechnology 21 (2010) 405504 (4pp) doi:10.10880957-44842140405504 On-chip SQUID measurements in the presence of high magnetic fields Lei Chen 1 , Wolfgang...

84

Migration and reorientation of grain boundaries in Zn bicrystals during annealing in a high magnetic field  

E-Print Network [OSTI]

. � 2002 Acta Materialia Inc. Published by Elsevier Science Ltd. All rights reserved. Keywords: Magnetic magnetic field A.D. Sheikh-Ali a,*,1 , D.A. Molodov b , H. Garmestani a a Laboratory for Micromechanics of Materials, FSU-National High Magnetic Field Laboratory and FAMU-FSU College of Engineering, 1800 East Paul

Garmestani, Hamid

85

Penetration of ac magnetic field into bulk high-temperature superconductors: Experiment and simulation  

E-Print Network [OSTI]

Penetration of ac magnetic field into bulk high-temperature superconductors: Experiment from these models for high-temperature superconductors are observed at the op- eration in ac fields condi- tions is very important for correct modeling magnetic prop- erties of high-temperature

Paperno, Eugene

86

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

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Hybrid Magnet? Now Playing: What's a Hybrid Magnet? Enable Javascript and Flash to stream the Magnet Minute Scott Hannahs Associated Links The World's Strongest Magnet (audio...

87

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

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Permanent Magnet? Now Playing: What's a Permanent Magnet? Enable Javascript and Flash to stream the Magnet Minute Scott Hannahs Associated Links Magnets from Mini to Mighty Meet...

88

The influence of a magnetic field on turbulent heat transfer of a high Prandtl number fluid  

E-Print Network [OSTI]

The influence of a magnetic field on turbulent heat transfer of a high Prandtl number fluid H magnetic field on the local and average heat transfer of an electrically conducting, turbulent fluid flow with high Prandtl number was studied experimentally. The mechanism of heat transfer modification due

Abdou, Mohamed

89

SP - 19 Magnetic Field Safety  

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

90

National High Magnetic Field Laboratory - Series Connected Hybrid  

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Magnet Lab Series Connected Hybrid for Magnet Lab Figure 1. Vertical Section of the Series Connected Hybrid Magnet for the Mag Lab. The Magnet Lab has embarked on innovative...

91

High-field, high-current-density, stable superconducting magnets for fusion machines  

SciTech Connect (OSTI)

Designs for large fusion machines require high-performance superconducting magnets to reduce cost or increase machine performance. By employing force-flow cooling, cable-in-conduit conductor configuration, and NbTi superconductor, it is now possible to design superconducting magnets that operate a high fields (8-12 T) with high current densities (5-15 kA/cm/sup 2/ over the winding pack) in a stable manner. High current density leads to smaller, lighter, and thus less expensive coils. The force-flow cooling provides confined helium, full conductor insulation, and a rigid winding pack for better load distribution. The cable-in-conduit conductor configuration ensures a high stability margin for the magnet. The NbTi superconductor has reached a good engineering material standard. Its strain-insensitive critical parameters are particularly suitable for complex coil windings of a stellarator machine. The optimization procedure for such a conductor design, developed over the past decade, is summarized here. If desired a magnet built on the principles outlines in this paper can be extended to a field higher than the design value without degrading its stability by simply lowering the operating temperature below 4.2 K. 11 refs., 3 figs.

Lue, J.W.; Dresner, L.; Lubell, M.S.

1989-01-01T23:59:59.000Z

92

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

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matter physicist who investigates magnetism of nanostructured objects including magnetic nanoparticles, biomolecules and biologically inspired materials. In her own words I...

93

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

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Investigators cited human error as the cause of the collision. Related Electricity & Magnetism Pages Maglev Trains: On Track with Superconductivity Magnets from Mini to Mighty If...

94

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

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was still unrealized. Davenport first became interested in electricity and magnetism when he heard about a magnet-based machine built by Joseph Henry used to separate...

95

National High Magnetic Field Laboratory Audio Dictionary: Quench  

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stream the Magnet Minute Bob Walsh Associated Links What's a Superconducting Magnet? (audio file) What's Superconductivity? (audio file) Superconductivity: Current in a Cape and...

96

Ultra-High Intensity Magnetic Field Generation in Dense Plasma  

SciTech Connect (OSTI)

I. Grant Objective The main objective of this grant proposal was to explore the efficient generation of intense currents. Whereasthefficient generation of electric current in low-­?energy-­? density plasma has occupied the attention of the magnetic fusion community for several decades, scant attention has been paid to carrying over to high-­?energy-­? density plasma the ideas for steady-­?state current drive developed for low-­?energy-­? density plasma, or, for that matter, to inventing new methodologies for generating electric current in high-­?energy-­?density plasma. What we proposed to do was to identify new mechanisms to accomplish current generation, and to assess the operation, physics, and engineering basis of new forms of current drive in regimes appropriate for new fusion concepts.

Fisch, Nathaniel J

2014-01-08T23:59:59.000Z

97

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

98

Magnetic Field Effect on Charmonium Production in High Energy Nuclear Collisions  

E-Print Network [OSTI]

It is important to understand the strong external magnetic field generated at the very beginning of high energy nuclear collisions. We study the effect of the magnetic field on the charmonium yield and anisotropic distribution in Pb+Pb collisions at the LHC energy. The time dependent Schr\\"odinger equation is employed to describe the motion of $c\\bar{c}$ pairs. We compare our model prediction of non- collective anisotropic parameter $v_2$ of $J/\\psi$s with CMS data at high transverse momentum. This is the first attempt to measure the magnetic field in high energy nuclear collisions.

Guo, Xingyu; Xu, Nu; Xu, Zhe; Zhuang, Pengfei

2015-01-01T23:59:59.000Z

99

National High Magnetic Field Laboratory - Finding Iron in Food...  

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cup A magnet Cereal and magnet What you'll do: Pour some of the food into a Ziploc bag. Seal the bag with as little air in it as possible, then mash the food until you make a...

100

New High Field Magnet for Neutron Scattering at Hahn-Meitner Institute  

E-Print Network [OSTI]

Abstract. The Berlin Neutron Scattering Center BENSC at the Hahn-Meitner-Institute (HMI) is a user facility for the study of structure and dynamics of condensed matter with neutrons and synchrotron radiation with special emphasis on experiments under extreme conditions. Neutron scattering is uniquely suited to study magnetic properties on a microscopic length scale, because neutrons have comparable wavelengths and, due to their magnetic moment, they interact with the atomic magnetic moments. Magnetic interactions and magnetic phenomena depend on thermodynamic parameters like magnetic field, temperature and pressure. At HMI special efforts are being made to offer outstanding sample environments such as very low temperatures or high magnetic fields or combination of both. For the future a dedicated instrument for neutron scattering at extreme fields is under construction, the Extreme Environment Diffractometer ExED. For this instrument the existing superconducting magnets as well as a future hybrid system can be used. The highest fields, above 30 T will be produced by the planned series-connected hybrid magnet system, designed and constructed in collaboration with the National High Magnetic Field Laboratory, Tallahassee, FL. 1.

M Steiner; D A Tennant; P Smeibidl

Note: This page contains sample records for the topic "high magnetic fields" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
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We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Giant Viscosity Enhancement in a Spin-Polarized Fermi Liquid National High Magnetic Field Laboratory  

E-Print Network [OSTI]

electrons, ultra-cold atoms, and 3He-4He mixtures. If the magnetic field is sufficiently high so~ 15 T, T~ 2mk), for which the spin polarization attains values greater than 99%. Akimoto, H.; Xia, J

Weston, Ken

102

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

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work "I do biomedical research, which utilizes my education and experience of Nuclear Magnetic Resonance (NMR). In particular, we design methods to increase the signal that we...

103

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

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to July 2004. Role Graduate research assistant and associate postdoc, Condensed Matter Science group in Tallahassee. Current work Investigating the electronic and magnetic...

104

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

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smaller than a basketball. My goal is to understand how quantum mechanics affects the magnetic properties of these molecules. "My most recent work was performed with two...

105

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

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Postdoctoral associate, University of Florida, College of Medicine and Advanced Magnetic Resonance Imaging and Spectroscopy facility. Current work Fatma works on C.elegans, a...

106

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

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William Sturgeon developed the first rotary electric motor, a forerunner of the present-day direct-current motor. Related Electricity & Magnetism Pages Timeline: 1820 182...

107

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

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such as bringing cable television into homes and connecting home video equipment. Related Electricity & Magnetism Pages Museum: Transatlantic Telegraph Cable Timeline: 1910 - 192...

108

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

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are used in plasma screens and various scientific apparatus in which power must be produced in a microwave frequency. Related Electricity & Magnetism Pages Timeline: 1920 1929...

109

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

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television, they were benefitting from De Forests discovery. Related Electricity & Magnetism Pages Pioneers: John Ambrose Fleming Pioneers: Lee De Forest Timeline: 1900 190...

110

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

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a special type of the mineral magnetite. All varieties of magnetite display signs of magnetism, but of them, only lodestone possesses distinctly north-south polarity. Lodestone...

111

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

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accomplish the same tasks and the choice between them comes down to individual tastes. Related Electricity & Magnetism Pages Interactive Java Tutorials: Electromagnetic Induction...

112

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

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in 1872), which argued that facial expressions are universal among humans and animals. Related Electricity & Magnetism Pages Pioneers: Luigi Galvani Timeline: 1850 186...

113

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theory that oxygen was an essential part of all acids. Related Electricity & Magnetism Pages Interactive Java Tutorials: Daniell Cell Interactive Java Tutorials: Simple...

114

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

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General Electric, an enduring giant in the electric industry. Related Electricity & Magnetism Pages Interactive Java Tutorials: Alternating Current Interactive Java Tutorials:...

115

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

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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...

116

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

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from our spinning CD players to dancing Santa Claus dolls. Related Electricity & Magnetism Pages Interactive Java Tutorials: Daniell Cell Interactive Java Tutorials: Simple...

117

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

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several Geiger counters at once to observe showers of cosmic rays, a phenomenon which became the focus of his research. Related Electricity & Magnetism Pages Timeline: 1900 190...

118

National High Magnetic Field Laboratory - Coexistence of Superconducti...  

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Coexistence of Superconductivity, Magnetism and FFLO States FFLO States The BCS (Bardeen, Cooper and Schrieffer, 1957) theory successfully explains conventional superconductivity...

119

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

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features allowing fast and easy on-the-spot measurements. Related Electricity & Magnetism Pages Electromagnetic Deflection in a Cathode Ray Tube, I Discovering how cathode...

120

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

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example, are often useful in widefield fluorescence microscopy. Related Electricity & Magnetism Pages Interactive Java Tutorials: Arc Lamp Museum: Fluorescent Lamp Pioneers: Sir...

Note: This page contains sample records for the topic "high magnetic fields" from the National Library of EnergyBeta (NLEBeta).
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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: Museum of Electricity...  

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others to observe the wonders of electrostatics first hand. Related Electricity & Magnetism Pages Pioneers: William Gilbert Timeline: 1600 1699 Tutorials: Electrostatic...

122

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

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method for measuring resistance is still widely used today. Related Electricity & Magnetism Pages Interactive Java Tutorials: Rheostat Interactive Java Tutorials: Wheatstone...

123

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

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in 1963, Magneto is a powerful mutant with the ability to generate and control magnetism. Magneto However, 132 years before Marvel comics introduced Magneto, the first...

124

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the number one cause of death in the United States today. Related Electricity & Magnetism Pages Interactive Java Tutorials: Electromagnetic Induction Interactive Java...

125

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and businesses as an energy-saving alternative to incandescent. Related Electricity & Magnetism Pages Interactive Java Tutorials: Arc Lamp Museum: Arc Lamp Pioneers: Nikola Tesla...

126

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important components in electronics, such as lights and radio. Related Electricity & Magnetism Pages Interactive Java Tutorial: Capacitor Interactive Java Tutorial: Electrostatic...

127

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

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century and continues to evolve and influence today's culture. Related Electricity & Magnetism Pages Morse Telegraph The man most commonly associated with the telegraph, Samuel...

128

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title in honor of his contributions to the transatlantic telegraph cable. Related Electricity & Magnetism Pages Museum: Morse Telegraph Pioneers: Lord Kelvin Timeline: 1850 186...

129

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

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uncharged arrangement is proportional to the radiation intensity. Related Electricity & Magnetism Pages Museum: Torsion Balance Pioneers: William Gilbert Timeline: 1775 1799...

130

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generators capable of generating larger and larger voltages. Related Electricity & Magnetism Pages Timeline: 600 BC - 1599 Timeline: 1600 - 1699 Timeline: 1700 - 1749 Tutorials:...

131

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

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Car batteries contain from 60 to 80 percent recycled materials. Related Electricity & Magnetism Pages Interactive Java Tutorials: Daniell Cell Interactive Java Tutorials: Simple...

132

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

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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...

133

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

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(sometimes called an atom smasher) can be miles long, a cyclotron can be small enough to slip inside your pocket. Related Electricity & Magnetism Pages Timeline: 1930 - 193...

134

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physics courses, the Wimshurst is often the electrostatic device of choice for demonstrations of static electricity. Related Electricity & Magnetism Pages Timeline: 1880 - 188...

135

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became the most profitable product of the great inventor. Related Electricity & Magnetism Pages Interactive Java Tutorials: Daniell Cell Interactive Java Tutorials: Simple...

136

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

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armature and numerous overlapped coils, his design remains the basis of many of today's direct-current electric motors. Related Electricity & Magnetism Pages Timeline: 1870 - 187...

137

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to the Italian scientist and inventor Alessandro Volta. Related Electricity & Magnetism Pages Interactive Java Tutorials: Daniell Cell Interactive Java Tutorials: Leyden...

138

CMI Unique Facility: Thermal Analysis in High Magnetic Fields...  

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guide efforts to create strong permanent magnets that use less of the critical rare earth elements. This facility supports the CMI efforts of developing substitutes, and...

139

National High Magnetic Field Laboratory Audio Dictionary: Spectrometer  

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Spectrometer? Now Playing: What's a Spectrometer? Enable Javascript and Flash to stream the Magnet Minute Munir Humayun Associated Links Mass Spectrometry: How to Weigh an Atom...

140

National High Magnetic Field Laboratory Audio Dictionary: User  

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at the Lab Science Highlights: Research by Visiting Scientists Visiting Scientists: Current and upcoming researchers and their experiments What's a Magnet Experiment (audio file)...

Note: This page contains sample records for the topic "high magnetic fields" 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.


141

Effect of high solenoidal magnetic fields on breakdown voltages of high vacuum 805 MHz cavities  

SciTech Connect (OSTI)

There is an on going international collaboration studying the feasibility and cost of building a muon collider or neutrino factory [1,2]. An important aspect of this study is the full understanding of ionization cooling of muons by many orders of magnitude for the collider case. An important muon ionization cooling experiment, MICE [3], has been proposed to demonstrate and validate the technology that could be used for cooling. Ionization cooling is accomplished by passing a high-emittance muon beam alternately through regions of low Z material, such as liquid hydrogen, and very high accelerating RF Cavities within a multi-Tesla solenoidal field. To determine the effect of very large solenoidal magnetic fields on the generation of dark current, x-rays and on the breakdown voltage gradients of vacuum RF cavities, a test facility has been established at Fermilab in Lab G. This facility consists of a 12 MW 805 MHz RF station and a large warm bore 5 T solenoidal superconducting magnet containing a pill box type cavity with thin removable window apertures. This system allows dark current and breakdown studies of different window configurations and materials. The results of this study will be presented. The study has shown that the peak achievable accelerating gradient is reduced by a factor greater than 2 when solenoidal field of greater than 2 T are applied to the cavity.

Moretti, A.; Bross, A.; Geer, S.; Qian, Z.; /Fermilab; Norem, J.; /Argonne; Li, D.; Zisman, M.; /LBL, Berkeley; Torun, Y.; /IIT, Chicago; Rimmer, R.; /Jefferson Lab; Errede,; /Illinois U., Urbana

2005-10-01T23:59:59.000Z

142

National High Magnetic Field Laboratory Press Release: October...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Commissioning of 100 Tesla Multi-Shot Pushes Boundaries of Science Beyond 80 Tesla October 19, 2006 Contact: Alex Lacerda, (505) 665-6504 2006october19 Dwight Rickel of the Magnet...

143

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Fisk, and my research today continues to be inspired by Zach. Zachs dedication to science and breadth of knowledge are truly inspirational. The Magnet Lab is very much the...

144

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

lamented in his later years, "I hate what they've done to my child ... I would never let my own children watch it." Related Electricity & Magnetism Pages Timeline: 1910 192...

145

National High Magnetic Field Laboratory - Pioneers in Electricity...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

to wave theory, Weber was very interested in the phenomena of electricity and magnetism. His interest in these areas he held in common with Carl Friedrich Gauss, with whom...

146

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

the fact that there is a computer there at all is owed in large part to Apples role in making computers personal. Related Electricity & Magnetism Pages Timeline: 1960 19...

147

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

On the big screen, a Tesla coil was used to produce lighting effects for the 1979 film "Star Trek: The Motion Picture." Related Electricity & Magnetism Pages Timeline: 1890 - 18...

148

Potential Formation in a High-Speed Plasma Flow along Converging Magnetic Field Lines  

Science Journals Connector (OSTI)

The formation of a potential is experimentally investigated in a high-speed collisionless plasma flow injected into a region of converging magnetic field lines. When the plasma passes through this region, a large increase in potential occurs there, resulting in electron acceleration along the magnetic field. A drastic end-plate effect on the generated potential is observed when the plasma comes in contact with the end plate.

N. Sato; Y. Watanabe; R. Hatakeyama; T. Mieno

1988-10-03T23:59:59.000Z

149

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

diagnostic cardiology and even helped garner a Nobel Prize. Electrocardiograph The field of electrophysiology dates back to Italian physician Luigi Galvani, and scientists...

150

Light weight, high field, stable, superconducting magnets for advanced transportation systems  

SciTech Connect (OSTI)

Although the Guideway may be the most expensive component of a MAGLEV system, the importance of a suitable magnet system should not be underestimated. The reliability of operation of MAGLEV depends on the superconducting magnets performing to their specifications in a reliable manner (i.e., without training or quenching). Besides reliability the magnets should produce high field, be sufficiently stable to withstand reasonable perturbations, be light weight, be protected in the event of a quench, and be economical (although performance should outweigh cost). We propose to develop superconducting magnets that have these features. Our magnet designs are based on internally cooled, cable-in-conduit superconductor with Polymer Matrix Composites (PMC) as the structural reinforcement. Although the initial work is with metallic superconductors such as NbTi, the processes being developed will be applicable to the High Temperature Ceramic Superconductors when they become suitable for magnet applications.

Lubell, M.S.; Dresner, L.; Kenney, W.J.; Lue, J.W.; Luton, J.N.; Schwenterly, S.W.

1991-01-01T23:59:59.000Z

151

Mechanical design of a high field common coil magnet  

E-Print Network [OSTI]

This paper presents the mechanical design for a 14 tesla 2-The design addresses mechanical issues particular to theLBNL #43481 SC MAG #668 MECHANICAL DESIGN OF A mGH FIELD

Caspi, S.

2011-01-01T23:59:59.000Z

152

National High Magnetic Field Laboratory - Portable Dilution Refrigerat...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Bottom Interface Shown on lab bench. PDF Rotating Probe Bottom Interface View a high-res version of this image....

153

X-Ray–Line Diagnostic of Magnetic Field Strength for High-Temperature Plasmas  

Science Journals Connector (OSTI)

An x-ray line diagnostic for use in magnetic field measurements in high-temperature plasmas has been identified. The intensity of the otherwise strictly forbidden 1s22s22p1/22p3/243s1/2??P03?1s22s22p6??S01 transition in neonlike ions is shown to depend on the magnetic field strength. The field dependence is illustrated between one and 3 T in the Ar8+ spectrum. The line is well resolved, bright, and close to reference lines, making it an experimentally simple to use diagnostic.

P. Beiersdorfer; J. H. Scofield; A. L. Osterheld

2003-06-13T23:59:59.000Z

154

National High Magnetic Field Laboratory: Clean, Keen, Machining...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

The shops most high-tech apparatus, a six-axis wire electrical discharge machine (EDM), was used to nail the tricky geometry of the center of the inch-wide part. Then...

155

Terahertz Zeeman spectroscopy of boron in germanium to high magnetic fields  

Science Journals Connector (OSTI)

The fundamental absorption lines of substitutional boron acceptor impurity in germanium, which lie between 1 and 3THz, now have been measured in magnetic fields to 18T, greatly extending the reach of both previous experiments (to 7T) and theory (to 10T). The Faraday configuration was employed with the magnetic field B??110?. Unexpected behavior has been observed relating to the magnetic-field-induced splitting of the ground and first two excited states (all of which are fourfold degenerate): (a) One pair of Zeeman ground states splits at only half the rate predicted with field; this behavior continues to high field. The other pair shows a rapid increase with field. (b) The two pairs of Zeeman states emerging from the first excited state initially separate with field, then, above 10T, converge, almost meeting by 18T. (c) One pair of the Zeeman states from the second excited state begins to plateau at high field; the other shows a dramatic decrease above 9T, extrapolated to become zero at around 24T. Taken together, these results suggest modification to the existing theory is required, and may have implications for quantum computation involving substitutional impurities.

R. E. M. Vickers; R. A. Lewis; P. Fisher; Y.-J. Wang

2008-03-26T23:59:59.000Z

156

Symmetry Breaking in Graphene Gregory S. Boebinger, National High Magnetic Field Laboratory  

E-Print Network [OSTI]

Symmetry Breaking in Graphene Gregory S. Boebinger, National High Magnetic Field Laboratory DMR. In this experiment, Landau levels in graphene were used to study the breaking of SU(4) symmetry--a higher dimensional states by their spin polarization. It was found that graphene turns into either a spin ferromagnet

Weston, Ken

157

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

158

Effects of intrinsic magnetostriction on tube-topology magnetoelectric sensors with high magnetic field sensitivity  

SciTech Connect (OSTI)

Three quasi-one-dimensional magnetoelectric (ME) magnetic field sensors, each with a different magnetostrictive wire material, were investigated in terms of sensitivity and noise floor. Magnetostrictive Galfenol, iron-cobalt-vanadium, and iron-nickel wires were examined. Sensitivity profiles, hysteresis effects, and noise floor measurements for both optimally biased and zero-biased conditions are presented. The FeNi wire (FN) exhibits high sensitivity (5.36?mV/Oe) at bias fields below 22?Oe and an optimal bias of 10?Oe, whereas FeGa wire (FG) exhibits higher sensitivity (6.89 mW/Oe) at bias fields >22?Oe. The sensor of FeCoV wire (FC) presents relatively low sensitivity (2.12?mV/Oe), due to low magnetostrictive coefficient. Each ME tube-topology sensor demonstrates relatively high sensitivity at zero bias field, which results from a magnetic shape anisotropy and internal strain of the thin magnetostrictive wire.

Gillette, Scott M.; Fitchorov, Trifon; Obi, Ogheneyunume; Chen, Yajie, E-mail: y.chen@neu.edu; Harris, Vincent G. [Department of Electrical and Computer Engineering, Northeastern University, Boston, Massachusetts 02115 (United States); Jiang, Liping; Hao, Hongbo; Wu, Shuangxia [Baotou Research Institute of Rare Earths, Baotou, Inner Mongolia 014030 (China)

2014-05-07T23:59:59.000Z

159

Performance of silicon PIN photodiodes at low temperatures and in high magnetic fields  

E-Print Network [OSTI]

The performance of a Si PIN diode (type Hamamatsu S3590-06) as an energy sen- sitive detector operating at cryogenic temperatures (~10 K) and in magnetic fields up to 11 T was investigated, using a 207Bi conversion electron source. It was found that the detector still performs well under these conditions, with small changes in the response function being observed in high magnetic fields, e.g. a 30% to 50% decrease in energy resolution. A GEANT4 Monte Carlo simulation showed that the observed effects are mainly due to the modified trajectories of the electrons due to the influence of the magnetic field, which changes the scattering conditions, rather than to intrinsic changes of the performance of the detector itself.

F. Wauters; I. S. Kraev; M. Tandecki; E. Traykov; S. Van Gorp; D. Zakoucky; N. Severijns

2008-12-31T23:59:59.000Z

160

Monitoring the magnetic field in houses under 50 Hz high-voltage overhead transmission lines  

Science Journals Connector (OSTI)

This paper deals with a one-week monitoring of the 50 Hz magnetic field on the ground floor and the first floor of houses under 150, 220 and 380 kV high-voltage overhead three-phase AC transmission lines. The field strength varied with the current intensity, the conductor height, and the storey of the house. Because current intensity varies with time the magnetic field depended on the time of day and the day of the week. The recorded magnetic field ranged from 0.1 µT to 4.5 µT. The maximum value was at least 20 times weaker than the 100 µT exposure level recommended by the guidelines of the International Radiation Protection Association (IRPA) and about 140 times smaller than the 640 µT of the European Prestandard (CENELEC). The B-field was, for 99.9% of the measuring time, larger than the 0.2 µT cut-off point used to define categories of exposed and unexposed subjects in EMF epidemiological studies and, for 99.3% of the time, was greater than the 0.3 µT level used by US private engineering companies as the 'prudent avoidance' exposure limit. The weakest average magnetic field was at least 40 times larger than the 0.02 µT background value.

G. Decat; J. Van Tongerloo

1998-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "high magnetic fields" 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

High-precision description and new properties of a spin-1 particle in a magnetic field  

E-Print Network [OSTI]

The exact Foldy-Wouthuysen Hamiltonian is derived for a pointlike spin-1 particle with a normal magnetic moment in a nonuniform magnetic field. For a uniform magnetic field, it is exactly separated into terms linear and quadratic in spin. New unexpected properties of a particle with an anomalous magnetic moment are found. Spin projections of a particle moving in a uniform magnetic field are not integer and the tensor polarization is asymmetric in the plane orthogonal to the field. Previously described spin-tensor effects caused by the tensor magnetic polarizability exist not only for nuclei but also for pointlike particles.

Alexander J. Silenko

2014-04-19T23:59:59.000Z

162

Cost Effective Open Geometry HTS MRI System amended to BSCCO 2212 Wire for High Field Magnets  

SciTech Connect (OSTI)

The original goal of this Phase II Superconductivity Partnership Initiative project was to build and operate a prototype Magnetic Resonance Imaging (MRI) system using high temperature superconductor (HTS) coils wound from continuously processed dip-coated BSCCO 2212 tape conductor. Using dip-coated tape, the plan was for MRI magnet coils to be wound to fit an established commercial open geometry, 0.2 Tesla permanent magnet system. New electronics and imaging software for a prototype higher field superconducting system would have added significantly to the cost. However, the use of the 0.2 T platform would allow the technical feasibility and the cost issues for HTS systems to be fully established. Also it would establish the energy efficiency and savings of HTS open MRI compared with resistive and permanent magnet systems. The commercial goal was an open geometry HTS MRI running at 0.5 T and 20 K. This low field open magnet was using resistive normal metal conductor and its heat loss was rather high around 15 kolwatts. It was expected that an HTS magnet would dissipate around 1 watt, significantly reduce power consumption. The SPI team assembled to achieve this goal was led by Oxford Instruments, Superconducting Technology (OST), who developed the method of producing commercial dip coated tape. Superconductive Components Inc. (SCI), a leading US supplier of HTS powders, supported the conductor optimization through powder optimization, scaling, and cost reduction. Oxford Magnet Technology (OMT), a joint venture between Oxford Instruments and Siemens and the world’s leading supplier of MRI magnet systems, was involved to design and build the HTS MRI magnet and cryogenics. Siemens Magnetic Resonance Division, a leading developer and supplier of complete MRI imaging systems, was expected to integrate the final system and perform imaging trials. The original MRI demonstration project was ended in July 2004 by mutual consent of Oxford Instruments and Siemens. Between the project start and that date a substantial shift in the MRI marketplace occurred, with rapid growth for systems at higher fields (1.5 T and above) and a consequent decline in the low field market (<1.0 T). While the project aim appeared technically attainable at that time, the conclusion was reached that the system and market economics do not warrant additional investment. The program was redirected to develop BSCCO 2212 multifilament wire development for high field superconducting magnets for NMR and other scientific research upon an agreement between DOE and Oxford Instruments, Superconducting Technology. The work t took place between September, 2004 and the project end in early 2006 was focused on 2212 multifilamentary wire. This report summarizes the technical achievements both in 2212 dip coated for an HTS MRI system and in BSCCO 2212 multifilamentary wire for high field magnets.

Kennth Marken

2006-08-11T23:59:59.000Z

163

Resistance minimum observed at Landau level filling factor ?=1/2 in ultra high magnetic fields  

Science Journals Connector (OSTI)

We study the magnetotransport near Landau level filling factor ?=1/2 in a gated GaAs-Al0.3Ga0.7As square quantum well (width 35 nm) in magnetic field up to 45 T and in a temperature (T) range between 50 mK and 1.5 K. The longitudinal resistance at ?=1/2, Rxx(?=1/2), exhibits a steep valley that is flanked by a pair of rising resistance peaks in low T. The Rxx(?=1/2) shows nonmonotonous dependence on T, with a minimum resistance reached at T?0.5?K. The concomitant Hall resistance Rxy is not strictly linear with magnetic field and its slope shows a sharp cusp at ?=1/2, indicating a nonclassical Hall effect. The data are characteristic for ultra high field magnetotransport around ?=1/2 in thick, but single-layer, quantum wells.

Jian Zhang; R. R. Du; J. A. Simmons; J. L. Reno

2010-01-21T23:59:59.000Z

164

High-field ac susceptometer using Helmholtz coils as a magnetizer  

Science Journals Connector (OSTI)

An ac susceptometer is designed for measuring ac susceptibility of disc, film or tape samples of high-temperature superconductors at 77 K in an applied field as high and uniform as possible. It is equipped with a pair of magnetizing Helmholtz coils and a pair of coaxial concentric measuring?compensating coils. For this, the field uniformity and impedance of the magnetizing Helmholtz coils with square coil cross-section and the flux linkage in the measuring?compensating coils produced by the sample moment are systematically and accurately computed based on the analytical formulae for the mutual inductance between two loops and the self-inductance of a thin solenoid. Problems related to the susceptometer calibration and the susceptibility measurements are discussed.

D-X Chen

2004-01-01T23:59:59.000Z

165

Polarization-preserving confocal microscope for optical experiments in a dilution refrigerator with high magnetic field  

E-Print Network [OSTI]

We present the design and operation of a fiber-based cryogenic confocal microscope. It is designed as a compact cold-finger that fits inside the bore of a superconducting magnet, and which is a modular unit that can be easily swapped between use in a dilution refrigerator and other cryostats. We aimed at application in quantum optical experiments with electron spins in semiconductors and the design has been optimized for driving with, and detection of optical fields with well-defined polarizations. This was implemented with optical access via a polarization maintaining fiber together with Voigt geometry at the cold finger, which circumvents Faraday rotations in the optical components in high magnetic fields. Our unit is versatile for use in experiments that measure photoluminescence, reflection, or transmission, as we demonstrate with a quantum optical experiment with an ensemble of donor-bound electrons in a thin GaAs film.

Maksym Sladkov; M. P. Bakker; A. U. Chaubal; D. Reuter; A. D. Wieck; C. H. van der Wal

2010-10-09T23:59:59.000Z

166

Polarization-preserving confocal microscope for optical experiments in a dilution refrigerator with high magnetic field  

E-Print Network [OSTI]

We present the design and operation of a fiber-based cryogenic confocal microscope. It is designed as a compact cold-finger that fits inside the bore of a superconducting magnet, and which is a modular unit that can be easily swapped between use in a dilution refrigerator and other cryostats. We aimed at application in quantum optical experiments with electron spins in semiconductors and the design has been optimized for driving with, and detection of optical fields with well-defined polarizations. This was implemented with optical access via a polarization maintaining fiber together with Voigt geometry at the cold finger, which circumvents Faraday rotations in the optical components in high magnetic fields. Our unit is versatile for use in experiments that measure photoluminescence, reflection, or transmission, as we demonstrate with a quantum optical experiment with an ensemble of donor-bound electrons in a thin GaAs film.

Sladkov, Maksym; Chaubal, A U; Reuter, D; Wieck, A D; van der Wal, C H

2010-01-01T23:59:59.000Z

167

Polarization-preserving confocal microscope for optical experiments in a dilution refrigerator with high magnetic field  

Science Journals Connector (OSTI)

We present the design and operation of a fiber-based cryogenic confocal microscope. It is designed as a compact cold-finger that fits inside the bore of a superconducting magnet and which is a modular unit that can be easily swapped between use in a dilution refrigerator and other cryostats. We aimed at application in quantum optical experiments with electron spins in semiconductors and the design has been optimized for driving with and detection of optical fields with well-defined polarizations. This was implemented with optical access via a polarization maintaining fiber together with Voigt geometry at the cold finger which circumvents Faraday rotations in the optical components in high magnetic fields. Our unit is versatile for use in experiments that measure photoluminescence reflection or transmission as we demonstrate with a quantum optical experiment with an ensemble of donor-bound electrons in a thin GaAs film.

Maksym Sladkov; M. P. Bakker; A. U. Chaubal; D. Reuter; A. D. Wieck; C. H. van der Wal

2011-01-01T23:59:59.000Z

168

Critical current and instability threshold measurement of Nb3Sn cables for high field accelerator magnets  

SciTech Connect (OSTI)

Rutherford-type cables made of high critical current Nb{sub 3}Sn strands are being used in several laboratories for developing new generation superconducting magnets for present and future accelerators and upgrades. Testing of cable short samples is an important part of these R&D programs and the instability problem found in some short model magnets at Fermilab made these tests even more significant. Fermilab in collaboration with BNL, CERN and LBNL has developed sample holders and sample preparation infrastructure and procedures for testing Nb{sub 3}Sn cable short samples at BNL and CERN test facilities. This paper describes the sample holders, sample preparation and instrumentation, and test results. Several samples made of MJR or PIT strands 1 mm in diameter have been tested. Some samples were unstable (i.e. quenched at low transport currents) at low fields and reached the critical surface at higher fields.

Ambrosio, G.; Andreev, N.; /Fermilab; Bartlett, S.E.; /LBL, Berkeley; Barzi, E.; /Fermilab; Denarie, C.-H.; /CERN; Dietderich, D.; /LBL, Berkeley; Ghosh, A.K.; /Brookhaven; Verweij, A.P.; /CERN; Zlobin, A.V.; /Fermilab

2004-11-01T23:59:59.000Z

169

A strong, highly-tilted interstellar magnetic field near the Solar System  

Science Journals Connector (OSTI)

... hydrogen was not taken into account. Here we report measurements of the deflection of the solar wind plasma flows in the heliosheath to determine the magnetic field strength and orientation in ... We conclude that the interstellar medium field is turbulent or has a distortion in the solar vicinity. The local interstellar medium magnetic field (BISM) is one of the key ...

M. Opher; F. Alouani Bibi; G. Toth; J. D. Richardson; V. V. Izmodenov; T. I. Gombosi

2009-12-24T23:59:59.000Z

170

Scientific Image Gallery from the Applied Superconductivity Center at the National High Magnetic Field Laboratory  

DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

The Applied Superconductivity Center (ASC) is nested with the National High Magnetic Field Laboratory. Originally located at the University of Wisconsin, ASC transferred to NHMFL or Magnet Lab in 2003. ASC investigates both low and high-temperature materials. Focus areas include grain boundaries; coated conductors, BSCCO, and a new superconductor known as MgB2. The ASC Image Gallery provides graphs with text descriptions and single images with captions. The single images are organized into collections under scientific titles, such as MgB2 mentioned above. Click on the Videos link to see two 3D videos and be sure to check out the link to image collections at other organizations performing superconductivity research.

171

Ternary superconductor NbTiTa'' for high field superfluid magnets  

SciTech Connect (OSTI)

The possibility exists to obtain a higher Hc{sub 2}' upper critical field in the NbTi system which is normally limited by a spin-orbit coupling term. The introduction of scattering reduces this coupling. The spin-orbit scattering rate is proportional to Z{sup 4} and therefore leads logically to the introduction of a high atomic number element which is more or less similar with respect to all of the other properties, i.e., Tc. Previous studies have shown Tantalum to be an excellent choice. The present work represents an attempt to obtain a high current density, high field ternary magnet conductor (Jc (10T, 2K, {rho}eff = 10{sup {minus}12} {Omega}-cm)) > 2000A/mm{sup 2}. This goal was met, but the conductor was clearly not optimized.

McInturff, A.D.; Carson, J. (Fermi National Accelerator Lab., Batavia, IL (USA)); Larbalestier, D.; Lee, P.; McKinnel, J. (Wisconsin Univ., Madison, WI (USA)); Kanithi, H. (IGC/Advanced Superconductors, Inc., Waterbury, CT (USA)); McDonald, W.; O'Larey, P. (Teledyne-Wah Chang, Albany, OR (USA))

1990-06-01T23:59:59.000Z

172

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

173

Anomalous peak at low fields in the magnetization versus temperature curve in bulk ceramic high-temperature superconductors  

Science Journals Connector (OSTI)

When a bulk ceramic high-temperature superconductor is cooled in a small field and the magnetic moment of the sample is measured as the sample is warmed, an anomalous peak in the magnetic moment is observed. This peak can be as high as 50% of the low-temperature moment for fields less than 1 Oe, but it rapidly decreases as the magnetic field increases. We show that this anomaly is due to the interrelationship between flux trapping by intergranular weak links and the irreversible flux trapping properties of the superconducting grains as recently described by Hao and Clem.

J. P. Wang and W. C. H. Joiner

1994-07-01T23:59:59.000Z

174

Observation of high-energy electrons accelerated by electrostatic waves propagating obliquely to a magnetic field  

Science Journals Connector (OSTI)

It is revealed in microwave-plasma interaction experiments that a large-amplitude electrostatic wave propagating obliquely to a magnetic field accelerates electrons strongly almost along the magnetic field lines via the process of Vp×B acceleration. The experimental results are in reasonable agreement with the theoretical prediction of Sugihara et al.

Yasushi Nishida and Naoyuki Sato

1987-08-10T23:59:59.000Z

175

SAND2011-6616A Page 1 Session 2: High Energy Density, Plasmas, Magnetic Fields  

National Nuclear Security Administration (NNSA)

616A 616A Page 1 Session 2: High Energy Density, Plasmas, Magnetic Fields Dynamical Materials Experiments on Sandia's Z Machine: Obtaining Data with High Precision at HED Conditions Thomas R. Mattsson and Seth Root Sandia National Laboratories, Albuquerque, NM USA Summary: The Z machine at Sandia National Laboratories has successfully been used to study a wide range of materials under extreme conditions. In this paper, we will discuss the methodology resulting in high-pressure measurements at multi-Mbar pressures as well as present experimental data for shock compression of poly methyl-pentene, a hydrocarbon plastic. Introduction During the last few years, there has been a notable increase in the interest of high-pressure science. The increase in interest has been driven by the remarkable capabilities of new and improved platforms like

176

Supported by the National Science Foundation and the State of Florida 1 REPORTSNATIONAL HIGH MAGNETIC FIELD LABORATORY  

E-Print Network [OSTI]

Supported by the National Science Foundation and the State of Florida 1 REPORTSNATIONAL HIGH MAGNETIC FIELD LABORATORY NHMFL SPRING 1997 Florida State University · University of Florida · Los Alamos National Laboratory the formation of convection currents in and NHMFL Magnets cont. on page 6 Recently

Weston, Ken

177

High-field magnetic ground state in S=12 kagome lattice antiferromagnet ZnCu3(OH)6Cl2  

Science Journals Connector (OSTI)

Herbertsmithite ZnCu3(OH)6Cl2 is a kagome lattice antiferromagnet with spin-1/2 and has been demonstrated to be a likely candidate of spin liquid by a number of recent experiments. The high-field magnetization of the kagome lattice is complicated due to the presence of a few percent of extra Cu impurities sitting on the interlayer metallic sites. To determine the magnetic ground state of the kagome lattice, we measured the magnetization of a single crystalline ZnCu3(OH)6Cl2 using torque magnetometry down to the base temperatures 20 mK in intense magnetic field as high as 31 T. The high-field intrinsic magnetization from the kagome lattice turns out to be linear with magnetic field, and the magnetic susceptibility is independent of temperature at 20mK?T?5 K. Moreover, below 2 K, several field-induced anomalies are observed in between 7 T and 15 T.

Tomoya Asaba; Tian-Heng Han; B. J. Lawson; F. Yu; C. Tinsman; Z. Xiang; G. Li; Young S. Lee; Lu Li

2014-08-18T23:59:59.000Z

178

Mode conversion and absorption of fast waves at high ion cyclotron harmonics in inhomogeneous magnetic fields  

SciTech Connect (OSTI)

The propagation and absorption of high harmonic fast waves is of interest for non-inductive current drives in fusion experiments. The fast wave can be coupled with the ion Bernstein wave that propagates in the high magnetic field side of an ion cyclotron harmonic resonance layer. This coupling and the absorption are analyzed using the hot plasma dispersion relation and a wave equation that was converted from an approximate dispersion relation for the case where ?{sub i}=k{sub ?}{sup 2}?{sub i}{sup 2}/2?1 (where k{sub ?} is the perpendicular wave number and ?{sub i} is the ion Larmor radius). It is found that both reflection and conversion may occur near the harmonic resonance layer but that they decrease rapidly, giving rise to a sharp increase in the absorption as the parallel wave number increases.

Cho, Suwon, E-mail: swcho@kgu.ac.kr [Department of Physics, Kyonggi University, Suwon, Kyonggi-Do 443-760 (Korea, Republic of)] [Department of Physics, Kyonggi University, Suwon, Kyonggi-Do 443-760 (Korea, Republic of); Kwak, Jong-Gu [National Fusion Research Institute, Daejeon 305-806 (Korea, Republic of)] [National Fusion Research Institute, Daejeon 305-806 (Korea, Republic of)

2014-04-15T23:59:59.000Z

179

Electron transport in confined structures in very high mobility GaAs in perpendicular magnetic fields  

E-Print Network [OSTI]

In this thesis we study properties of two-dimensional electron transport through constrictions in perpendicular magnetic fields. We present two sets of experiments, one focusing on properties in the integer quantum Hall ...

Radu, Iuliana

2009-01-01T23:59:59.000Z

180

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

Note: This page contains sample records for the topic "high magnetic fields" 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

Terahertz Spectroscopy of Spin Waves in Multiferroic BiFeO3 in High Magnetic Fields  

DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

We have studied the magnetic field dependence of far-infrared active magnetic modes in a single ferroelectric domain BiFeO3 crystal at low temperature. The modes soften close to the critical field of 18.8 T along the [001] (pseudocubic) axis, where the cycloidal structure changes to the homogeneous canted antiferromagnetic state and a new strong mode with linear field dependence appears that persists at least up to 31 T. A microscopic model that includes two Dzyaloshinskii-Moriya interactions and easy-axis anisotropy describes closely both the zero-field spectroscopic modes as well as their splitting and evolution in a magnetic field. The good agreement of theory with experiment suggests that the proposed model provides the foundation for future technological applications of this multiferroic material.

Nagel, U.; Fishman, Randy S.; Katuwal, T.; Engelkamp, H.; Talbayev, D.; Yi, Hee Taek; Cheong, S.-W.; Rõõm, T.

2013-06-01T23:59:59.000Z

182

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

183

High Magnetic Field Processing - A Heat-Free Heat Treating Method  

SciTech Connect (OSTI)

The High and Thermal Magnetic Processing/Electro-magnetic Acoustic Transducer (HTMP/EMAT) technology has been shown to be an enabling disruptive materials processing technology, that can achieve significant improvements in microstructure and consequently material performance beyond that achievable through conventional processing, and will lead to the next generation of advanced performance structural and functional materials. HTMP exposure increased the reaction kinetics enabling refinement of microstructural features such as finer martensite lath size, and finer, more copious, homogeneous dispersions of strengthening carbides leading to combined strength and toughness improvements in bainitic steels. When induction heating is applied in a high magnetic field environment, the induction heating coil is configured so that high intensity acoustic/ultrasonic treatment occurs naturally. The configuration results in a highly effective electromagnetic acoustical transducer (EMAT). HTMP combined with applying high-field EMAT, produce a non-contact ultrasonic treatment that can be used to process metal alloys in either the liquid state resulting in significant microstructural changes over conventional processing. Proof-of-principle experiments on cast irons resulted in homogeneous microstructures in small castings along with improved casting surface appearance. The experiment showed that by exposing liquid metal to the non-contact acoustic/ultrasonic processing technology developed using HMFP/EMAT wrought-like microstructures were developed in cast components. This Energy Intensive Processes (EIP) project sponsored by the DOE EERE Advanced Manufacturing Office (AMO) demonstrated the following: (1) The reduction of retained austenite in high carbon/high alloy steels with an ambient temperature HTMP process, replacing either a cryogenic or double tempering thermal process normally employed to accomplish retained austenite transformation. HTMP can be described as a 'heat-free', heat treating technology. Lower residual stresses in HTMP treated materials are anticipated since no thermal strains are involved in inducing the transformation of retained austenite to martensite in high alloy steel. (2) The simultaneous increase of 12% in yield strength and 22% in impact energy in a bainitic alloy using HTMP processing. This is a major breakthrough in materials processing for the next generation of structural materials since conventionally processed materials show a reduction in impact toughness with an increase in yield strength. HTMP is a new paradigm to beneficially increase both yield strength and impact energy absorption simultaneously. (3) HTMP processing refined both the martensite lath population and the carbide dispersion in a bainitic steel alloy during Gausstempering. The refinement was believed to be responsible for the simultaneous increase in strength and toughness. Hence, HTMP significantly impacts nucleation and growth phenomenon. (4) HTMP processing developed comparable ultimate tensile strength and twice the impact energy in a lower cost, lower alloy content ({approx}8% alloy content) steel, compared to highly alloyed, (31% alloy elements involving Ni, Co, and Mo) 250-grade margining steel. Future low-cost HTMP alloys appear viable that will exceed the structural performance of highly alloyed materials that are conventionally processed. This economic benefit will enable U.S. industry to reduce cost (better more competitive worldwide) while maintaining or exceeding current performance. (5) EMAT processed cast iron exhibits significantly higher hardness (by 51% for a 9T condition) than a no-field processed sample. (6) EMAT produced microstructures in cast iron resulted in an unique graphite nodule morphology, a modified pearlite content, and unique carbide types, that formed during solidification and cooling. (7) EMAT processed nanoparticle dispersions in Mg resulted in a very fine, unagglomerated distribution of the nanoparticles in the magnesium matrix. This provides a breakthrough technology to make the next generation of

Ludtka, Gerard Michael [ORNL; Ludtka, Gail Mackiewicz- [ORNL; Wilgen, John B [ORNL; Kenik, Edward A [ORNL; Parish, Chad M [ORNL; Rios, Orlando [ORNL; Rogers, Hiram [ORNL; Manuel, Michele [University of Florida, Gainesville; Kisner, Roger A [ORNL; Watkins, Thomas R [ORNL; Murphy, Bart L [ORNL

2012-08-01T23:59:59.000Z

184

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

185

Characterization of a high-temperature superconducting conductor on round core cables in magnetic fields up to 20 T  

SciTech Connect (OSTI)

The next generation of high-field magnets that will operate at magnetic fields substantially above 20 T, or at temperatures substantially above 4.2 K, requires high-temperature superconductors (HTS). Conductor on round core (CORC) cables, in which RE-Ba{sub 2}Cu{sub 3}O{sub 7-{delta}} (RE = rare earth) (REBCO) coated conductors are wound in a helical fashion on a fl?exible core, are a practical and versatile HTS cable option for low-inductance, high-field magnets. We performed the first tests of CORC magnet cables in liquid helium in magnetic fields of up to 20 T. A record critical current I{sub c} of 5021 A was measured at 4.2 K and 19 T. In a cable with an outer diameter of 7.5 mm, this value corresponds to an engineering current density J{sub e} of 114 A mm{sup -2} , the highest J{sub e} ever reported for a superconducting cable at such high magnetic fields. Additionally, the first magnet wound from an HTS cable was constructed from a 6 m-long CORC cable. The 12-turn, double-layer magnet had an inner diameter of 9 cm and was tested in a magnetic field of 20 T, at which it had an I{sub c} of 1966 A. The cables were quenched repetitively without degradation during the measurements, demonstrating the feasibility of HTS CORC cables for use in high-field magnet applications.

van der Laan, Danko [Advanced Conductor Technologies; Noyes, Patrick [National High Magnetic Field Laboratory; Miller, George [National High Magnetic Field Laboratory; Weijers, Hubertus [National High Magnetic Field Laboratory; Willering, Gerard [CERN

2013-02-13T23:59:59.000Z

186

Faceted growth of primary Al{sub 2}Cu crystals during directional solidification in high magnetic field  

SciTech Connect (OSTI)

The high magnetic field is widely used to modify the crystal morphology. In this work, the effect of the magnetic field on growing behavior of faceted crystals in the Al-40 wt. %Cu alloy was investigated using directional solidification technique. It was found that the faceted growth of primary Al{sub 2}Cu phase was degraded and the primary spacing was reduced upon applying the magnetic field. Additionally, the length of the mushy zone first decreased and then increased with increase of the magnetic field intensity. The quantitative analysis reveals that the shear stress induced by the fluid motion is insufficient to break the atom bonds at the solid-liquid interface. However, both of the thermoelectric magnetic convection (TEMC) and the thermoelectric magnetic force (TEMF) cause dendrites to fracture and reduce the primary spacing. The two effects also weaken the faceting growth. Moreover, the instability of the solid-liquid interface is generated by the TEMF, which further leads to degrade the faceted growth. The length of mushy zone was changed by the TEMC and reached the minimum in the magnetic field of 0.5 T, which is in good agreement with the predicted value (0.83 T)

Li, Chuanjun; Ren, Zhongming; Shen, Yu [School of Materials Science and Engineering, Shanghai University, Shanghai 200072 (China)] [School of Materials Science and Engineering, Shanghai University, Shanghai 200072 (China); Wang, Qiuliang; Dai, Yinming; Wang, Hui [Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190 (China)] [Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190 (China)

2013-10-21T23:59:59.000Z

187

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

188

Ultra-high quality factors in superconducting niobium cavities in ambient magnetic fields up to 190 mG  

E-Print Network [OSTI]

Ambient magnetic field, if trapped in the penetration depth, leads to the residual resistance and therefore sets the limit for the achievable quality factors in superconducting niobium resonators for particle accelerators. Here we show that a complete expulsion of the magnetic flux can be performed and leads to: 1) record quality factors $Q > 2\\times10^{11}$ up to accelerating gradient of 22 MV/m; 2) $Q\\sim3\\times10^{10}$ at 2 K and 16 MV/m in up to 190 mG magnetic fields. This is achieved by large thermal gradients at the normal/superconducting phase front during the cooldown. Our findings open up a way to ultra-high quality factors at low temperatures and show an alternative to the sophisticated magnetic shielding implemented in modern superconducting accelerators.

Romanenko, A; Crawford, A C; Sergatskov, D A; Melnychuk, O

2014-01-01T23:59:59.000Z

189

Stress Management as an Enabling Technology for High-Field Superconducting Dipole Magnets  

E-Print Network [OSTI]

-Pounds HD High field Dipole HGQ High Gradient Quadrupole HQ High field Quadrupole HT Heat Treatment IC Critical Current IFCC Inter-Filament Coupling Currents ITER International Thermonuclear Experimental Reactor vi LARP LHC Accelerator... pressure impregnation (VPI) vessel using NbTi conductor [1, 2]. TAMU2 verified the heat treatment equipment and tested the stress management technology at low field using low Jc Nb3Sn conductor from the International Thermonuclear Experimental Reactor...

Holik, Eddie Frank

2014-06-03T23:59:59.000Z

190

High-Frequency Conductivity of a Plasma in Quasi-Equilibrium. II. Effect of a Uniform Magnetic Field  

Science Journals Connector (OSTI)

A general expression for high-frequency conductivity is derived to include the effect of an external magnetic field. The limit of large ion mass is also discussed. For the special case that the unperturbed plasma is in thermodynamic equilibrium, the result obtained in the present paper reduces immediately to that previously discussed by Oberman and Shure.

Ching-Sheng Wu

1965-10-04T23:59:59.000Z

191

Luminescence of coupled quantum wells:?Effects of indirect excitons in high in-plane magnetic fields  

Science Journals Connector (OSTI)

Luminescence measurements of a Ga1?xAlxAs?GaAs double quantum well in in-plane magnetic fields up to 22T are reported. The properties of spatially direct and indirect excitons are studied. We show that the strong indirect exciton luminescence survives in samples with low nonradiative recombination up to high in-plane magnetic fields. This contrasts with previously published results, where its strong suppression, observed for magnetic fields as low as of 10T, was explained by the exciton center-of-mass momentum conservation. We attribute the discrepancy to a relatively low nonradiative recombination in the studied sample in comparison with the radiative recombination of localized indirect excitons.

M. Orlita, R. Grill, M. Zvára, G. H. Döhler, S. Malzer, M. Byszewski, and J. Soubusta

2004-08-20T23:59:59.000Z

192

Specification of fields quality in the interaction region magnets of the high luminosity LHC based on dynamic aperture  

E-Print Network [OSTI]

New large aperture Inner Triplet quadrupoles, separation dipoles and the nearby matching quadrupoles will be installed in the low-beta interaction regions (IR) of the high luminosity LHC upgrade (HL-LHC) [1]. The large aperture is necessary for accommodating the increased beam size due to much higher beta functions in these magnets for the low collision optics. The high beta functionswill amplify the effects of field errors in the new magnets leading to a smaller dynamic aperture (DA). It is, therefore, critical to evaluate the impact of these errors on the DA and specify the magnet field quality (FQ) satisfying an acceptable DA while being realistically achievable. The study is performed for the HL-LHC lattice layouts SLHCV3.1b and HLLHCV1.0 for collision and injection energies.

Nosochkov, Y; Wang, M H; Fartoukh, S; Giovannozzi, M; De Maria, R; McIntosh, E

2014-01-01T23:59:59.000Z

193

Theory of high-power cyclotron-resonance heating in an inhomogeneous magnetic field  

Science Journals Connector (OSTI)

Wave-energy absorption of a plasma due to cyclotron harmonic resonance is evaluated analytically and by a simulation. The static magnetic field is characterized with B??B=0, and a longitudinal wave is supposed to propagate across the magnetic field. In the calculation an orbit modification of the cyclotron motion of particles is taken into account. It is found that the absorption for the fundamental harmonic resonance (m=1) is depressed from that of the conventional linear theory while the absorptions for m?2 are enhanced, where m is the harmonic number. The enhancement is significant when k?t?1 (k the perpendicular wave number and ?t the gyroradius of the thermal particle) and when the interaction time between the plasma particles and the wave exceeds a critical value that is obtainable analytically. For all m and k?t, there appear peaks or saturations in the time evolution of the absorbed energy.

Ryo Sugihara and Yuichi Ogawa

1992-03-15T23:59:59.000Z

194

High-Frequency Conductivity of Quantum Plasma in a Magnetic Field  

Science Journals Connector (OSTI)

The problem of the electromagnetic absorption coefficient in a quantum plasma in the presence of a uniform magnetic field is investigated by a kinetic description. The finite duration of encounters is taken into account in a self-consistent fashion which includes collective effects properly. This treatment is the quantum extension of an earlier classical study. The application of this theory to heavily doped semiconductors is suggested.

Carl Oberman and Amiram Ron

1963-05-15T23:59:59.000Z

195

Alignment of Self-Assembled Hierarchical Microstructure in Liquid Crystalline Diblock Copolymers Using High Magnetic Fields  

Science Journals Connector (OSTI)

Large area microdomain alignment in a ferroelectric liquid crystalline diblock copolymer (LCBCP) poly(styrene)-block-poly(isoprene-LC), (PS?PILC), incorporating a biphenyl 3-nitro-4-alkoxy-benzoate LC mesogenic group and a non-LC block hexagonally packed cylinder microstructure, was successfully accomplished by application of a magnetic field at elevated temperatures. ... Figure 1 Chemical structure of the PS?PILC diblock copolymers. ... PS?PILC ...

Chinedum Osuji; Paulo J. Ferreira; Guoping Mao; Christopher K. Ober; John B. Vander Sande; Edwin L. Thomas

2004-11-26T23:59:59.000Z

196

A HIGH-FIELD PULSED SOLENOID MAGNET FOR LIQUID METAL TARGET STUDIES  

E-Print Network [OSTI]

studies have been car- ried out for rotating-band targets, a tantalum/water target, and a liquid parameters for a pulsed solenoid, including the magnet cryogenic sys- tem and power supply, that can generate, the operation of rf cavities near high-power targets, and evaluation of target materials. Mercury Jet + Proton

McDonald, Kirk

197

Study of the influence of a strong magnetic field on the composition of nuclear matter at high densities and zero temperature  

SciTech Connect (OSTI)

Magnetars are neutron stars with a strong surface magnetic field. Observations of soft gamma-ray and anomalous X-ray pulsars pointed out that the surface magnetic field of magnetars is equal or even greater than 10{sup 15} G. In this work we study the influence of a strong magnetic field on the composition of nuclear matter at high densities and zero temperature. We describe the matter through a relativistic mean-field model with eight light baryons (baryon octet), electrons, muons and with magnetic field. As output of the numerical calculations, we obtain the relative population of each species of particles as function of baryon density.

Coelho, Eduardo L.; Chiapparini, Marcelo [Instituto de Fisica, Universidade do Estado do Rio de Janeiro, 20559-900, Rio de Janeiro, RJ (Brazil); Bracco, Mirian E. [Faculdade de Tecnologia, Universidade do Estado do Rio de Janeiro, 27537-000, Resende, RJ (Brazil)

2013-03-25T23:59:59.000Z

198

Evidence of Magnetic Breakdown on the Defects With Thermally Suppressed Critical Field in High Gradient SRF Cavities  

SciTech Connect (OSTI)

At SRF 2011 we presented the study of quenches in high gradient SRF cavities with dual mode excitation technique. The data differed from measurements done in 80's that indicated thermal breakdown nature of quenches in SRF cavities. In this contribution we present analysis of the data that indicates that our recent data for high gradient quenches is consistent with the magnetic breakdown on the defects with thermally suppressed critical field. From the parametric fits derived within the model we estimate the critical breakdown fields.

Eremeev, Grigory [JLAB; Palczewski, Ari [JLAB

2013-09-01T23:59:59.000Z

199

High-energy neutrino conversion into electron-W pair in magnetic field and its contribution to neutrino absorption  

E-Print Network [OSTI]

We calculate the conversion rate of high-energy neutrinos propagating in constant magnetic field into an electron-W pair (nu -> W + e) from the imaginary part of the neutrino self-energy. Using the exact propagators in constant magnetic field, the neutrino self-energy has been calculated to all order in the field within the Weinberg-Salam model. We obtain a compact formula in the limit of B << Bcr = m^2/e. We find that above the process threshold Eth \\~ 2.2 10^16 (Bcr / B) eV this contribution to the absorption of neutrinos yields an asymptotic absorption length ~ 1.1 (Bcr / B)^2 (10^{16} eV / E) meters.

Andrea Erdas; Marcello Lissia

2002-08-12T23:59:59.000Z

200

Zero-Energy State in Graphene in a High Magnetic Field Joseph G. Checkelsky, Lu Li, and N. P. Ong  

E-Print Network [OSTI]

Zero-Energy State in Graphene in a High Magnetic Field Joseph G. Checkelsky, Lu Li, and N. P. Ong-carrying excitations. DOI: 10.1103/PhysRevLett.100.206801 PACS numbers: 73.63.ÿb, 73.21.ÿb, 73.43.ÿf The discovery. The inset shows sample K22 in false color (dark red) with Au leads deposited (yellow regions). The bar

Ong, N. P.

Note: This page contains sample records for the topic "high magnetic fields" 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

A broadband microwave Corbino spectrometer at $^3$He temperatures and high magnetic fields  

E-Print Network [OSTI]

We present the technical details of a broadband microwave spectrometer for measuring the complex conductance of thin films covering the range from 50 MHz up to 16 GHz in the temperature range 300 mK to 6 K and at applied magnetic fields up to 8 Tesla. We measure the complex reflection from a sample terminating a coaxial transmission line and calibrate the signals with three standards with known reflection coefficients. Thermal isolation of the heat load from the inner conductor is accomplished by including a section of NbTi superconducting cable (transition temperature around 8 $-$ 9 K) and hermetic seal glass bead adapters. This enables us to stabilize the base temperature of the sample stage at 300 mK. However, the inclusion of this superconducting cable complicates the calibration procedure. We document the effects of the superconducting cable on our calibration procedure and the effects of applied magnetic fields and how we control the temperature with great repeatability for each measurement. We have suc...

Liu, Wei; Armitage, N P

2014-01-01T23:59:59.000Z

202

Effects of electron-electron interactions on the electronic Raman scattering of graphite in high magnetic fields  

Science Journals Connector (OSTI)

We report the observation of strongly temperature (T)-dependent spectral lines in electronic Raman-scattering spectra of graphite in a high magnetic field up to 45 T applied along the c axis. The magnetic field quantizes the in-plane motion, while the out-of-plane motion remains free, effectively reducing the system dimension from 3 to 1. Optically created electron-hole pairs interact with, or shake up, the one-dimensional Fermi sea in the lowest Landau subbands. Based on the Tomonaga-Luttinger liquid theory, we show that interaction effects modify the spectral line shape from (???)?1/2 to (???)2??1/2 at T = 0. At finite T, we predict a thermal broadening factor that increases linearly with T. Our model reproduces the observed T-dependent line shape, determining the electron-electron interaction parameter ? to be ?0.05 at 40 T.

Y. Ma; Y. Kim; N. G. Kalugin; A. Lombardo; A. C. Ferrari; J. Kono; A. Imambekov; D. Smirnov

2014-03-05T23:59:59.000Z

203

Anomalies in Ultra-High-Field Magnetic Superconductors (Eu1-xSnx)Mo6S8  

Science Journals Connector (OSTI)

Resistive behavior of three series of Chevrel phase, (Eu1-xSnx)Mo6S7, (Eu1-xSnx)Mo6S6.75 and (Eu1-xSnx)0.9Mo6S6.75, is studied in magnetic fields up to 90 kOe at temperatures down to 50 mK. Compounds with x>0.4 are usual ultra-high-field superconductors, while (Eu0.9Sn0.1)0.9Mo6S6.75 is a simple magnetic superconductor. Resistive behavior of the compounds between the above mentioned two sides is complicated, varying with the composition. For example, in (Eu0.8Sn0.2)Mo6S7 the resistance at high fields keeps roughly constant and the temperature dependence of Hc2 defined as a half of the resistance in the normal state is quite different with that defined at the appearance of the resistance. In (Eu0.85Sn0.15)Mo6S7 the superconductivity (=zero resistance) seems to reappear at high fields and at low temperatures.

Masahiro Isino; Norio Kobayashi; Yoshio Muto

1980-01-01T23:59:59.000Z

204

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

205

Magnetoacoustic tomography with magnetic induction for high-resolution bioimepedance imaging through vector source reconstruction under the static field of MRI magnet  

SciTech Connect (OSTI)

Purpose: Magnetoacoustic tomography with magnetic induction (MAT-MI) is an imaging modality to reconstruct the electrical conductivity of biological tissue based on the acoustic measurements of Lorentz force induced tissue vibration. This study presents the feasibility of the authors' new MAT-MI system and vector source imaging algorithm to perform a complete reconstruction of the conductivity distribution of real biological tissues with ultrasound spatial resolution. Methods: In the present study, using ultrasound beamformation, imaging point spread functions are designed to reconstruct the induced vector source in the object which is used to estimate the object conductivity distribution. Both numerical studies and phantom experiments are performed to demonstrate the merits of the proposed method. Also, through the numerical simulations, the full width half maximum of the imaging point spread function is calculated to estimate of the spatial resolution. The tissue phantom experiments are performed with a MAT-MI imaging system in the static field of a 9.4 T magnetic resonance imaging magnet. Results: The image reconstruction through vector beamformation in the numerical and experimental studies gives a reliable estimate of the conductivity distribution in the object with a ?1.5 mm spatial resolution corresponding to the imaging system frequency of 500 kHz ultrasound. In addition, the experiment results suggest that MAT-MI under high static magnetic field environment is able to reconstruct images of tissue-mimicking gel phantoms and real tissue samples with reliable conductivity contrast. Conclusions: The results demonstrate that MAT-MI is able to image the electrical conductivity properties of biological tissues with better than 2 mm spatial resolution at 500 kHz, and the imaging with MAT-MI under a high static magnetic field environment is able to provide improved imaging contrast for biological tissue conductivity reconstruction.

Mariappan, Leo; Hu, Gang [Department of Biomedical Engineering, University of Minnesota, Minnesota 55455 (United States)] [Department of Biomedical Engineering, University of Minnesota, Minnesota 55455 (United States); He, Bin, E-mail: binhe@umn.edu [Department of Biomedical Engineering, University of Minnesota, Minnesota 55455 and Institute of Engineering in Medicine, University of Minnesota, Minnesota 55455 (United States)] [Department of Biomedical Engineering, University of Minnesota, Minnesota 55455 and Institute of Engineering in Medicine, University of Minnesota, Minnesota 55455 (United States)

2014-02-15T23:59:59.000Z

206

On the GCR intensity and the inversion of the heliospheric magnetic field during the periods of the high solar activity  

E-Print Network [OSTI]

We consider the long-term behavior of the solar and heliospheric parameters and the GCR intensity in the periods of high solar activity and the inversions of heliospheric magnetic field (HMF). The classification of the HMF polarity structures and the meaning of the HMF inversion are discussed. The procedure is considered how to use the known HMF polarity distribution for the GCR intensity modeling during the periods of high solar activity. We also briefly discuss the development and the nearest future of the sunspot activity and the GCR intensity in the current unusual solar cycle 24.

Krainev, M B

2014-01-01T23:59:59.000Z

207

THE GALACTIC MAGNETIC FIELD  

SciTech Connect (OSTI)

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

208

Magneto-optical effects on shallow donor states in 6H-SiC in high magnetic fields  

Science Journals Connector (OSTI)

Impurity excitation spectra in 6H-SiC doped with nitrogen donors are studied by infrared absorption measurements in the frequency range 200–1400 cm-1 under the influence of high magnetic fields up to 20 T. No line splitting is observed for any orientation of the magnetic field. However, four transitions show a diamagnetic shift if the magnetic field is oriented along the crystal c axis. This diamagnetic shift is found to be anisotropic, depending on the orientation of the viewing direction towards c. From these results we conclude that the effective mass ellipsoids describing the conduction-band minima must be oriented along lines of the Brillouin zone, which are parallel to the crystal c axis, and that the effective mass tensor has three independent components. Using the symmetry oproperties of the Brillouin zone it is shown that the conduction-band minimum must be located somewhere along the line M-L in the Brillouin zone. From the experimental results at B=20 T it is estimated that the average effective mass m*=(mxmymz)1/3 must be m*>0.3m0.

F. Engelbrecht; S. Huant; R. Helbig

1995-10-15T23:59:59.000Z

209

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

210

Field-dependent critical state of high-Tc superconducting strip simultaneously exposed to transport current and perpendicular magnetic field  

SciTech Connect (OSTI)

We present an exact analytical approach for arbitrary field-dependent critical state of high-T{sub c} superconducting strip with transport current. The sheet current and flux-density profiles are derived by solving the integral equations, which agree with experiments quite well. For small transport current, the approximate explicit expressions of sheet current, flux-density and penetration depth for the Kim model are derived based on the mean value theorem for integration. We also extend the results to the field-dependent critical state of superconducting strip in the simultaneous presence of applied field and transport current. The sheet current distributions calculated by the Kim model agree with experiments better than that by the Bean model. Moreover, the lines in the I{sub a}-B{sub a} plane for the Kim model are not monotonic, which is quite different from that the Bean model. The results reveal that the maximum transport current in thin superconducting strip will decrease with increasing applied field which vanishes for the Bean model. The results of this paper are useful to calculate ac susceptibility and ac loss.

Xue, Cun; He, An; Yong, Huadong; Zhou, Youhe, E-mail: zhouyh@lzu.edu.cn [Key Laboratory of Mechanics on Disaster and Environment in Western China attached to the Ministry of Education of China, and Department of Mechanics and Engineering Sciences, College of Civil Engineering and Mechanics, Lanzhou University, Lanzhou, Gansu 730000 (China)] [Key Laboratory of Mechanics on Disaster and Environment in Western China attached to the Ministry of Education of China, and Department of Mechanics and Engineering Sciences, College of Civil Engineering and Mechanics, Lanzhou University, Lanzhou, Gansu 730000 (China)

2013-12-15T23:59:59.000Z

211

Separation of magnetic field lines  

SciTech Connect (OSTI)

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

212

Accurate correction of magnetic field instabilities for high-resolution isochronous mass measurements in storage rings  

E-Print Network [OSTI]

Isochronous mass spectrometry (IMS) in storage rings is a successful technique for accurate mass measurements of short-lived nuclides with relative precision of about $10^{-5}-10^{-7}$. Instabilities of the magnetic fields in storage rings are one of the major contributions limiting the achievable mass resolving power, which is directly related to the precision of the obtained mass values. A new data analysis method is proposed allowing one to minimise the effect of such instabilities. The masses of the previously measured at the CSRe $^{41}$Ti, $^{43}$V, $^{47}$Mn, $^{49}$Fe, $^{53}$Ni and $^{55}$Cu nuclides were re-determined with this method. An improvement of the mass precision by a factor of $\\sim 1.7$ has been achieved for $^{41}$Ti and $^{43}$V. The method can be applied to any isochronous mass experiment irrespective of the accelerator facility. Furthermore, the method can be used as an on-line tool for checking the isochronous conditions of the storage ring.

P. Shuai; H. S. Xu; Y. H. Zhang; Yu. A. Litvinov; M. Wang; X. L. Tu; K. Blaum; X. H. Zhou; Y. J. Yuan; G. Audi; X. L. Yan; X. C. Chen; X. Xu; W. Zhang; B. H. Sun; T. Yamaguchi; R. J. Chen; C. Y. Fu; Z. Ge; W. J. Huang; D. W. Liu; Y. M. Xing; Q. Zeng

2014-07-13T23:59:59.000Z

213

Exploration of Quench Initiation Due to Intentional Geometrical Defects in a High Magnetic Field Region of an SRF Cavity  

SciTech Connect (OSTI)

A computer program which was used to simulate and analyze the thermal behaviors of SRF cavities has been developed at Jefferson Lab using C++ code. This code was also used to verify the quench initiation due to geometrical defects in high magnetic field region of SRF cavities. We built a CEBAF single cell cavity with 4 artificial defects near equator, and this cavity has been tested with T-mapping. The preheating behavior and quench initiation analysis of this cavity will be presented here using the computer program.

J. Dai, K. Zhao, G.V. Eremeev, R.L. Geng, A.D. Palczewski; Dai, J. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Palczewski, A. D. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Eremeev, G. V. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Geng, R. L. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Zhao, K. [Institute of Heavy Ion Physics, Peking University, Beijing (China)

2011-07-01T23:59:59.000Z

214

High-Harmonic Fast-Wave Power Flow along Magnetic Field Lines in the Scrape-Off Layer of NSTX  

Science Journals Connector (OSTI)

A significant fraction of high-harmonic fast-wave (HHFW) power applied to NSTX can be lost to the scrape-off layer (SOL) and deposited in bright and hot spirals on the divertor rather than in the core plasma. We show that the HHFW power flows to these spirals along magnetic field lines passing through the SOL in front of the antenna, implying that the HHFW power couples across the entire width of the SOL rather than mostly at the antenna face. This result will help guide future efforts to understand and minimize these edge losses in order to maximize fast-wave heating and current drive.

R. J. Perkins; J. C. Hosea; G. J. Kramer; J.-W. Ahn; R. E. Bell; A. Diallo; S. Gerhardt; T. K. Gray; D. L. Green; E. F. Jaeger; M. A. Jaworski; B. P. LeBlanc; A. McLean; R. Maingi; C. K. Phillips; L. Roquemore; P. M. Ryan; S. Sabbagh; G. Taylor; J. R. Wilson

2012-07-27T23:59:59.000Z

215

High-Harmonic Fast-Wave Power Flow Along Magnetic Field Lines in the Scrape-Off Layer of NSTX  

SciTech Connect (OSTI)

A significant fraction of high-harmonic fast-wave (HHFW) power applied to NSTX can be lost to the scrape-off layer (SOL) and deposited in bright and hot spirals on the divertor rather than in the core plasma. We show that the HHFW power flows to these spirals along magnetic field lines passing through the SOL in front of the antenna, implying that the HHFW power couples across the entire width of the SOL rather than mostly at the antenna face. This result will help guide future efforts to understand and minimize these edge losses in order to maximize fast-wave heating and current drive.

Perkins, R. J. [Princeton Plasma Physics Laboratory (PPPL); Hosea, J. [Princeton Plasma Physics Laboratory (PPPL); Kramer, G. [Princeton Plasma Physics Laboratory (PPPL); Ahn, Joonwook [ORNL; Bell, R. E. [Princeton Plasma Physics Laboratory (PPPL); Diallo, A. [Princeton Plasma Physics Laboratory (PPPL); Gerhardt, S. [Princeton Plasma Physics Laboratory (PPPL); Gray, T. K. [Oak Ridge National Laboratory (ORNL); Green, David L [ORNL; Jaeger, Erwin Frederick [ORNL; Jaworski, M. A. [Princeton Plasma Physics Laboratory (PPPL); LeBlanc, B [Princeton Plasma Physics Laboratory (PPPL); McLean, Adam G [ORNL; Maingi, Rajesh [ORNL; Phillips, C. K. [Princeton Plasma Physics Laboratory (PPPL); Roquemore, L. [Princeton Plasma Physics Laboratory (PPPL); Ryan, Philip Michael [ORNL; Sabbagh, S. A. [Columbia University; Taylor, G. [Princeton Plasma Physics Laboratory (PPPL); Wilson, J. R. [Princeton Plasma Physics Laboratory (PPPL)

2012-01-01T23:59:59.000Z

216

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

217

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

218

OBSERVATION OF HIGH-SPEED OUTFLOWS IN CORONAL LOOPS ASSOCIATED WITH PHOTOSPHERIC MAGNETIC FIELD EVOLUTION  

SciTech Connect (OSTI)

Using SDO/AIA instruments, we provide an EUV observation of two adjacent loop strands (Loops 1 and 2) with one side of their footpoints rooted in the boundaries of active region (AR) NOAA 11158 and the other side in the quiet-Sun regions. The AR footpoints of Loop 1 were located in monopolar magnetic areas and those of Loop 2 in mixed polar areas (SDO/HMI magnetograms). There were no apparent outflows found in Loop 1 in 10 hr of observations, whereas in Loop 2, the outflows were detected throughout the whole observation with an average speed of 120-150 km s{sup -1}. We find clear evidence of magnetic reconnections occurring in the AR footpoints of Loop 2 (the opposite magnetic polarities came close and then a part of them disappeared) and magnetic flux dispersal in the quiet-Sun footpoints (a patch of positive polarities decayed with time). Furthermore, with Hinode/SOT observations, there were no significant Ca II H brightenings detected at the loop footpoints of Loop 2 at the chromospheric heights in response to those of the AIA 171 A and 304 A channels when four strong outflow events took place in the loops, which seem to differ from the conclusions of previous studies. In other studies, the rapid coronal outflows along the coronal loops were found to originate from the chromosphere through transient events (e.g., type II spicules).

Su, J. T.; Liu, S.; Mao, X. J. [Key Laboratory of Solar Activity, National Astronomical Observatories, Chinese Academy of Science, Beijing 100012 (China); Liu, Y.; Shen, Y. D. [National Astronomical Observatories/Yunnan Observatory, Chinese Academy of Sciences, Kunming 650011 (China)

2012-11-20T23:59:59.000Z

219

ARC: A compact, high-field, fusion nuclear science facility and demonstration power plant with demountable magnets  

E-Print Network [OSTI]

The affordable, robust, compact (ARC) reactor conceptual design study aims to reduce the size, cost, and complexity of a combined fusion nuclear science facility (FNSF) and demonstration fusion Pilot power plant. ARC is a 270 MWe tokamak reactor with a major radius of 3.3 m, a minor radius of 1.1 m, and an on-axis magnetic field of 9.2 T. ARC has rare earth barium copper oxide (REBCO) superconducting toroidal field coils, which have joints to enable disassembly. This allows the vacuum vessel to be replaced quickly, mitigating first wall survivability concerns, and permits a single device to test many vacuum vessel designs and divertor materials. The design point has a plasma fusion gain of Q_p~13.6, yet is fully non-inductive, with a modest bootstrap fraction of only ~63%. Thus ARC offers a high power gain with relatively large external control of the current profile. This highly attractive combination is enabled by the ~23 T peak field on coil with newly available REBCO superconductor technology. External cu...

Sorbom, B N; Palmer, T R; Mangiarotti, F J; Sierchio, J M; Bonoli, P; Kasten, C; Sutherland, D A; Barnard, H S; Haakonsen, C B; Goh, J; Sung, C; Whyte, D G

2014-01-01T23:59:59.000Z

220

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.

Note: This page contains sample records for the topic "high magnetic fields" 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

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

222

SAFETY PROCEDURE SP-24 NATIONAL HIGH MAGNETIC  

E-Print Network [OSTI]

SAFETY PROCEDURE SP-24 NATIONAL HIGH MAGNETIC FIELD LABORATORY NHMFL FLORIDA STATE UNIVERSITY SAFETY PROCEDURE SP-24 VISITOR AND CONTRACTOR SAFETY DIRECTOR, ENVIRONMENTAL, HEALTH, SAFETY & SECURITY Angela Sutton

Weston, Ken

223

EXPERIMENTAL INVESTIGATION OF TURBULENT HEAT TRANSFER OF HIGH PRANDTL NUMBER FLUID FLOW UNDER STRONG MAGNETIC FIELD  

E-Print Network [OSTI]

EXPERIMENTAL INVESTIGATION OF TURBULENT HEAT TRANSFER OF HIGH PRANDTL NUMBER FLUID FLOW UNDER to the heat transfer characteristic: Flibe is a high Prandtl number fluid. For high Prandtl number fluid, there is a severe limitation of temperature window due to its high melting point. The turbulent heat transfer is

Abdou, Mohamed

224

Magnetic field in a finite toroidal domain  

SciTech Connect (OSTI)

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

225

Effect of a constant magnetic field on echo signals in high-temperature superconductor powders  

Science Journals Connector (OSTI)

The generation of acoustic and vortex oscillations in high-temperature superconductor (HTSC) powders excited by radiofrequency (rf...

E. G. Apushkinskii; M. S. Astrov

2013-03-01T23:59:59.000Z

226

Landau-Level Splitting in Graphene in High Magnetic Fields Z. Jiang,1,3  

E-Print Network [OSTI]

indicates that the Landau level at the charge neutral Dirac point splits into four sublevels, lifting fields B > 20 T, indicating the lifting of the fourfold degeneracy of the previously observed QH states be attributed to lifting of the spin degeneracy of the n 1 Landau level. DOI: 10.1103/PhysRevLett.96

Kim, Philip

227

Radio-frequency measurements of UNiX compounds (X= Al, Ga, Ge) in high magnetic fields  

SciTech Connect (OSTI)

We performed radio-frequency (RF) skin-depth measurements of antiferromagnetic UNiX compounds (X=Al, Ga, Ge) in magnetic fields up to 60 T and at temperatures between 1.4 to {approx}60 K. Magnetic fields are applied along different crystallographic directions and RF penetration-depth was measured using a tunnel-diode oscillator (TDO) circuit. The sample is coupled to the inductive element of a TDO resonant tank circuit, and the shift in the resonant frequency {Delta}f of the circuit is measured. The UNiX compounds exhibit field-induced magnetic transitions at low temperatures, and those transitions are accompanied by a drastic change in {Delta}f. The results of our skin-depth measurements were compared with previously published B-T phase diagrams for these three compounds.

Mielke, Charles H [Los Alamos National Laboratory; Mcdonald, David R [Los Alamos National Laboratory; Zapf, Vivien [Los Alamos National Laboratory; Altarawneh, Moaz M [Los Alamos National Laboratory; Lacerda, Alex H [Los Alamos National Laboratory; Adak, Sourav [Los Alamos National Laboratory; Karunakar, Kothapalli [Los Alamos National Laboratory; Nakotte, Heinrich [Los Alamos National Laboratory; Chang, S [NIST; Alsmadi, A M [HASHEMITE UNIV; Alyones, S [HASHEMIT UNIV

2009-01-01T23:59:59.000Z

228

A Scanning Tunneling Microscope at the Milli-Kelvin, High Magnetic Field  

E-Print Network [OSTI]

preparation in ultra-high vac- uum (UHV) and spectroscopic mapping with an electronic temperature of 240 mK.3 K) directly leverage the resulting combination of ultra-low temperature and atomic resolution

Petta, Jason

229

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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...

230

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

231

Wire codes, magnetic fields, and childhood cancer  

SciTech Connect (OSTI)

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

232

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

233

High-resolution measurements of the spatial and temporal evolution of megagauss magnetic fields created in intense short-pulse laser-plasma interactions  

SciTech Connect (OSTI)

A pump-probe polarimetric technique is demonstrated, which provides a complete, temporally and spatially resolved mapping of the megagauss magnetic fields generated in intense short-pulse laser-plasma interactions. A normally incident time-delayed probe pulse reflected from its critical surface undergoes a change in its ellipticity according to the magneto-optic Cotton-Mouton effect due to the azimuthal nature of the ambient self-generated megagauss magnetic fields. The temporal resolution of the magnetic field mapping is typically of the order of the pulsewidth, limited by the laser intensity contrast, whereas a spatial resolution of a few ?m is achieved by this optical technique. High-harmonics of the probe can be employed to penetrate deeper into the plasma to even near-solid densities. The spatial and temporal evolution of the megagauss magnetic fields at the target front as well as at the target rear are presented. The ?m-scale resolution of the magnetic field mapping provides valuable information on the filamentary instabilities at the target front, whereas probing the target rear mirrors the highly complex fast electron transport in intense laser-plasma interactions.

Chatterjee, Gourab, E-mail: gourab@tifr.res.in; Singh, Prashant Kumar; Adak, Amitava; Lad, Amit D.; Kumar, G. Ravindra, E-mail: grk@tifr.res.in [Tata Institute of Fundamental Research, 1 Homi Bhabha Road, Mumbai 400 005 (India)

2014-01-15T23:59:59.000Z

234

Prospects for the Use of HTS in High Field Magnets for Future Accelerator Facilities  

E-Print Network [OSTI]

The enthusiasm that followed discovery of High Temperature Superconductors (HTS) and the initial genuine hope of a replacement technology that could have taken over from conventional Low Temperature Superconductors (LTS) was damped during the years by difficulties in reaching performance levels of competing materials: insufficient current-carrying performance, short piece lengths, and fragility of the brittle oxide superconductors made development of applications slow and limited to demonstrators or devices less demanding from the point of view of conductor performance. However, thanks to a continuous R&D effort, significant progress was made in the past years on the development of cuprate superconductors. Today long lengths of BSCCO 2223 (km range) and REBCO (a more general acronym for YBCO, where RE = Rare Earth) tape (hundreds of meters range) conductor with controlled and homogeneous characteristics are commercially available, and tremendous progress has been made in the development of BSSCO 2212 roun...

Ballarino, A

2014-01-01T23:59:59.000Z

235

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

236

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

237

Simulation of the influence high-frequency (2 MHz) capacitive gas discharge and magnetic field on the plasma sheath near a surface in hypersonic gas flow  

SciTech Connect (OSTI)

The plasma sheath near the surface of a hypersonic aircraft formed under associative ionization behind the shock front shields the transmission and reception of radio signals. Using two-dimensional kinetic particle-in-cell simulations, we consider the change in plasma-sheath parameters near a flat surface in a hypersonic flow under the action of electrical and magnetic fields. The combined action of a high-frequency 2-MHz capacitive discharge, a constant voltage, and a magnetic field on the plasma sheath allows the local electron density to be reduced manyfold.

Schweigert, I. V., E-mail: ischweig@itam.nsc.ru [Russian Academy of Sciences, Khristianovich Institute of Theoretical and Applied Mechanics, Siberian Branch (Russian Federation)

2012-08-15T23:59:59.000Z

238

Zero-Field Splitting in Pseudotetrahedral Co(II) Complexes: a Magnetic, High-Frequency and -Field EPR, and Computational Study  

Science Journals Connector (OSTI)

(4) In this case the correlation is represented by a straight line (in fact by two, nearly collinear, straight lines) for a geometry of compressed/elongated tetragonal bipyramid keeping D4h symmetry. ... magnet behavior in the absence of an applied magnetic field. ... ESR technique in magnetic fields ?17 T. A field-induced development of the soliton-like incommensurate superstructure is clearly indicated as a pronounced increase of the magnon spin resonance linewidth ?B, with a ?Bmax at Bc ? 13.8 T. The anomaly is explained in terms of the magnon-soliton scattering and suggests that the soliton-like phase exists close to the boundary of the dimerized-incommensurate phase transition. ...

Monika Idešicová; Ján Titiš; J. Krzystek; Roman Bo?a

2013-08-07T23:59:59.000Z

239

Variable-field permanent magnet dipole  

SciTech Connect (OSTI)

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

240

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

Note: This page contains sample records for the topic "high magnetic fields" 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

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

242

High field gradient particle accelerator  

DOE Patents [OSTI]

A high electric field gradient electron accelerator utilizing short duration, microwave radiation, and capable of operating at high field gradients for high energy physics applications or at reduced electric field gradients for high average current intermediate energy accelerator applications is disclosed. Particles are accelerated in a smooth bore, periodic undulating waveguide, wherein the period is so selected that the particles slip an integral number of cycles of the r.f. wave every period of the structure. This phase step of the particles produces substantially continuous acceleration in a traveling wave without transverse magnetic or other guide means for the particle. 10 figs.

Nation, J.A.; Greenwald, S.

1989-05-30T23:59:59.000Z

243

High field gradient particle accelerator  

DOE Patents [OSTI]

A high electric field gradient electron accelerator utilizing short duration, microwave radiation, and capable of operating at high field gradients for high energy physics applications or at reduced electric field gradients for high average current intermediate energy accelerator applications. Particles are accelerated in a smooth bore, periodic undulating waveguide, wherein the period is so selected that the particles slip an integral number of cycles of the r.f. wave every period of the structure. This phase step of the particles produces substantially continuous acceleration in a traveling wave without transverse magnetic or other guide means for the particle.

Nation, John A. (Ithaca, NY); Greenwald, Shlomo (Haifa, IL)

1989-01-01T23:59:59.000Z

244

Application of a magnetized coaxial plasma gun for formation of a high-beta field-reversed configuration  

Science Journals Connector (OSTI)

We have tested a field-reversed configuration (FRC) formation with a spheromak injection for the first time. In this method, initial pre-ionized plasma is injected as a magnetized spheromak-like plasmoid into the discharge chamber prior to main field reversal. The FRC plasma with an electron density of 1.3 × 1021 m?3, a separatrix radius of 0.04 m and a plasma length of 0.8 m was produced successfully in initial background plasma of about 1.6 × 1019 m?3 by spheromak injection. The density is about one third of the conventional formed by the z-ionized method.

T. Nishida; T. Kiguchi; T. Asai; T. Takahashi; Y. Matsuzawa; T. Okano; Y. Nogi

2006-01-01T23:59:59.000Z

245

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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...

246

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

247

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

248

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

249

High temperature, permanent magnet biased, homopolar magnetic bearing actuator  

E-Print Network [OSTI]

current resistance and improves the system efficiency because the magnetic field of the HTPM can suspend the major portion of the static load on bearing. A high temperature radial magnetic bearing was designed via an iterative search employing 3D finite...

Hossain, Mohammad Ahsan

2006-10-30T23:59:59.000Z

250

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

251

EVOLUTION OF MAGNETIC FIELDS IN HIGH-MASS STAR FORMATION: LINKING FIELD GEOMETRY AND COLLAPSE FOR THE W51 e2/e8 CORES  

SciTech Connect (OSTI)

We report our observational results of 870 {mu}m continuum emission and its linear polarization in the massive star formation site W51 e2/e8. Inferred from the linear polarization maps, the magnetic field in the plane of sky (B{sub perpendicular}) is traced with an angular resolution of 0.''7 with the Submillimeter Array. Whereas previous BIMA observations with an angular resolution of 3'' (0.1 pc) showed a uniform B field, our revealed B{sub perpendicular} morphology is hourglass-like in the collapsing core near the ultracompact H II region e2 and also possibly in e8. The decrease in polarization near the continuum peak seen at lower angular resolution is apparently due to the more complex structures at smaller scales. In e2, the pinched direction of the hourglass-like B-field morphology is parallel to the plane of the ionized accretion flow traced by H53{alpha}, suggesting that the massive stars are formed via processes similar to the low-mass stars, i.e., accretion through a disk, except that the mass involved is much larger. Furthermore, our finding that the resolved collapsing cores in e2 and e8 lie within one subcritical 0.5 pc envelope supports the scenario of magnetic fragmentation via ambipolar diffusion. We therefore suggest that magnetic fields control the dynamical evolution of the envelope and cores in W51 e2 and e8.

Tang, Y.-W. [Department of Physics, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan (China); Ho, Paul T. P.; Koch, Patrick M.; Lai, S.-P. [Academia Sinica Institute of Astronomy and Astrophysics, P. B. Box 23-141, Taipei 10617, Taiwan (China); Girart, Josep M. [Institut de Ciencies de l'Espai (CSIC-IEEC), Campus UAB, Facultat de Ciencies, Torre C5-parell 2, 08193 Bellaterra, Catalunya (Spain); Rao, Ramprasad [Submillimeter Array, Academia Sinica Institute of Astronomy and Astrophysics, 645 N. Aohoku P1, HI 9672 (United States)

2009-07-20T23:59:59.000Z

252

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

253

Magnetic reconnection in weakly collisional highly magnetized electron-ion plasmas  

E-Print Network [OSTI]

Magnetic reconnection in weakly collisional highly magnetized electron-ion plasmas Richard three-field model of two-dimensional magnetic reconnection in a weakly collisional, highly magnetized.1063/1.3374427 I. INTRODUCTION Magnetic reconnection is a fundamental physical phe- nomenon which occurs

Fitzpatrick, Richard

254

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

255

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

256

Rotating copper plasmoid in external magnetic field  

SciTech Connect (OSTI)

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

257

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

258

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

259

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

260

The ESRF Miniature Pulsed Magnetic Field System  

SciTech Connect (OSTI)

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

Note: This page contains sample records for the topic "high magnetic fields" 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

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

262

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

263

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

264

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

265

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

266

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

267

Unique topological characterization of braided magnetic fields  

SciTech Connect (OSTI)

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

268

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

269

Magnetic Vortex Core Reversal by Low-Field Excitations  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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.

270

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

271

Strongest non-destructive magnetic field: world record set at 100-tesla  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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

272

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

273

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

274

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

275

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

276

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

277

Magnetic Vortex Core Reversal by Low-Field Excitations  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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.

278

Magnetic Vortex Core Reversal by Low-Field Excitations  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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.

279

Magnetic Vortex Core Reversal by Low-Field Excitations  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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.

280

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

Note: This page contains sample records for the topic "high magnetic fields" 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

Magnetic field decay in model SSC dipoles  

SciTech Connect (OSTI)

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

282

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

283

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

284

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

285

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

286

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

287

Investigation of relaxation phenomena in high-temperature superconductors HoBa2Cu3O7-d at the action of pulsed magnetic fields  

E-Print Network [OSTI]

It is used the mechanical method of Abrikosov vortex stimulated dynamics investigation in superconductors. With its help it was studied relaxation phenomena in vortex matter of high-temperature superconductors. It established that pulsed magnetic fields change the course of relaxation processes taking place in vortex matter. The study of the influence of magnetic pulses differing by their durations and amplitudes on vortex system of isotropic high-temperature superconductors system HoBa2Cu3O7-d showed the presence of threshold phenomena. The small duration pulses does not change the course of relaxation processes taking place in vortex matter. When the duration of pulses exceeds some critical value (threshold), then their influence change the course of relaxation process which is revealed by stepwise change of relaxing mechanical moment . These investigations showed that the time for formatting of Abrikosov vortex lattice in HoBa2Cu3O7-d is of the order of 20 microsec. which on the order of value exceeds the time necessary for formation of a single vortex observed in type II superconductors.

J. G. Chigvinadze; J. V. Acrivos; S. M. Ashimov; A. A. Iashvili; T. V. Machaidze; Th. Wolf

2007-04-03T23:59:59.000Z

288

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

289

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

290

Warm inflation in presence of magnetic fields  

SciTech Connect (OSTI)

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

291

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

292

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

293

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

294

External-field-free magnetic biosensor  

SciTech Connect (OSTI)

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

295

Theoretical description of the high-field susceptibility of magnetically ordered transition metal systems with applications to Fe, Co, Ni, and Fe1?xCox  

Science Journals Connector (OSTI)

A theoretical description of the high-field susceptibility of magnetically ordered transition metal systems is presented that is based on linear response theory formulated using the Green’s function technique. The approach allows to treat all spin and orbital contributions in a consistent way on the same footing. In contrast to previous work, the Landau susceptibility is included and spin-orbit induced contributions to the susceptibility are accessible by using a fully relativistic formulation. As an application of our approach, results obtained for the ferromagnetic transition metals Fe, Co, and Ni, as well as for the alloy system Fe1?xCox, are presented. These are discussed and compared to corresponding experimental data.

S. Mankovsky and H. Ebert

2006-08-15T23:59:59.000Z

296

Structural consequences of hen egg-white lysozyme orthorhombic crystal growth in a high magnetic field: validation of X-ray diffraction intensity, conformational energy searching and quantitative analysis of B factors and mosaicity  

Science Journals Connector (OSTI)

It has been shown that a high magnetic field of 10 T improves the quality of lysozyme crystals as quantified by comparison of the X-ray diffraction of crystals grown in the presence and absence of a magnetic field of 10 T, from structure comparisons and from molecular-modelling studies with conformational energy searching, from analysis of the anisotropic B factors and finally from analysis of the mosaicity. It is concluded that magnetic enhancement in protein crystal perfection is an important material engineering tool in the study of protein structure and function.

Saijo, S.

2005-02-24T23:59:59.000Z

297

Magnetosheath conditions and magnetopause structure for high magnetic shear  

Science Journals Connector (OSTI)

The supersonic solar wind - Earth's magnetosphere coupling plays the main role in the solar wind energy, momentum and mass input into the magnetosphere. A new dynamic model of the magnetic field in the coupled solar wind — magnetosphere system taking into account bow shock formation is considered. The solution for plasma flow and magnetic field upstream and downstream the bow shock was obtained in kinematic approximation. The magnetic field near the magnetopause was compared with those obtained in terms of subsonic solar wind - magnetosphere interaction. For typical magnetosheath conditions, the former is about twice the latter. The magnetic field near the magnetopause is formed due to mutual diffusion of the magnetospheric and interplanetary magnetic fields. The proposed model allows to determine reconnection efficiency by IMF and solar wind parameters: velocity, density, conductivity. The calculated magnetic field in the magnetosheath is compared with those measured by AMPTEARM satellite for high magnetopause magnetic shear.

V.V. Kalegaev

2000-01-01T23:59:59.000Z

298

ASYMMETRIC DIFFUSION OF MAGNETIC FIELD LINES  

SciTech Connect (OSTI)

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

299

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

300

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

Note: This page contains sample records for the topic "high magnetic fields" from the National Library of EnergyBeta (NLEBeta).
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they are not comprehensive nor are they the most current set.
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to obtain the most current and comprehensive results.


301

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

302

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

303

Magnetic Vortex Core Reversal by Low-Field Excitations  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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...

304

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

305

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

306

Magnetic horizons of ultra-high energy cosmic rays  

E-Print Network [OSTI]

The propagation of ultra-high energy cosmic rays in extragalactic magnetic fields can be diffusive, depending on the strength and properties of the fields. In some cases the propagation time of the particles can be comparable to the age of the universe, causing a suppression in the flux measured on Earth. In this work we use magnetic field distributions from cosmological simulations to assess the existence of a magnetic horizon at energies around 10$^{18}$ eV.

Batista, Rafael Alves

2014-01-01T23:59:59.000Z

307

Magnetic Field Measurements and Analysis For an Aladdin Dipole Magnet  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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

308

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

309

MRS photodiode in strong magnetic field  

SciTech Connect (OSTI)

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

310

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

311

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

312

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

313

Spin dynamics in a spin-correlated radical pair of photosystem I. Pulsed time-resolved EPR at high magnetic field.  

SciTech Connect (OSTI)

Spin-dynamics of the spin-correlated radical pair (SCRP) P{sub 700}{sup +}A{sub 1A}{sup -} in the photosystem I (PSI) reaction center protein have been investigated with high-frequency (HF), time-resolved EPR spectroscopy. The superior spectral resolution of HF EPR enables spin-dynamics for both the donor and acceptor radicals in the pair to be monitored independently. Decay constants of each spin were measured as a function of temperature and compared to data obtained at X-band EPR. Relaxation times, T{sub 1}, and decay rates, k{sub S}, are the same at both X- and D-band magnetic fields. The spin-dynamics within the radical pair were determined from theoretical simulation of experimental time-resolved HF EPR spectra. At low temperatures, T < 60 K, the decay of the SCRP from the singlet state, k{sub S}, is the predominant process, while at high temperatures, T > 130 K, the T{sub 1} relaxation is much faster than k{sub S}. The recombination rate k{sub S} was observed to decrease as the temperature is increased. These EPR spectral results are in agreement with previously reported optical measurements of P{sub 700}{sup +}A{sub 1}{sup -} radical pair recombination.

Poluektov, O. G.; Paschenko, S. V.; Utschig, L. M.; Chemical Sciences and Engineering Division

2009-01-01T23:59:59.000Z

314

Results of magnetic field measurements of SPring-8 magnets  

SciTech Connect (OSTI)

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

315

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

316

Hyperon bulk viscosity in strong magnetic fields  

SciTech Connect (OSTI)

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

317

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

318

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

319

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

320

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

SciTech Connect (OSTI)

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

Note: This page contains sample records for the topic "high magnetic fields" 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

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

322

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.

323

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

324

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

325

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

326

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

327

Bound states in a strong magnetic field  

SciTech Connect (OSTI)

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

328

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

329

National High Magnetic Field Laboratory - Superconducting Magnet...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Interface SCM2 Straight Probe Drawing (PDF) Other Cryostats, Dewars, Probes and Sample Holders General Purpose 3He and 4He Systems 3He System B Portable Dilution Refrigerator SCM1...

330

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

331

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

332

Influence of the pulsating electric field on the ECR heating in a nonuniform magnetic field  

SciTech Connect (OSTI)

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

333

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

334

Magnetic field distortions produced by protective cages around sea turtle nests: unintended consequences for orientation  

E-Print Network [OSTI]

Magnetic field distortions produced by protective cages around sea turtle nests: unintended January 2003; received in revised form 8 July 2003; accepted 21 July 2003 Abstract The EarthÃ?s magnetic in cages has a high magnetic per- meability and might therefore affect the nearby field. Here we report

Lohmann, Kenneth J.

335

Magnetic-Field Induced Quantum Phase Transitions in Triangular-Lattice Antiferromagnets  

E-Print Network [OSTI]

Magnetic-Field Induced Quantum Phase Transitions in Triangular-Lattice Antiferromagnets T Ono1, H Department of Physics, Smith College, Northampton, Massachusetts 01063, USA 5 National High Magnetic Field are magnetically described as quasi-two-dimensional triangular-lattice antiferromagnets with spin-1 2 and 1

McQuade, D. Tyler

336

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

337

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

338

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

339

Circular polarization of obliquely propagating whistler wave magnetic field  

SciTech Connect (OSTI)

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

340

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

Note: This page contains sample records for the topic "high magnetic fields" 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

Rotational and magnetic field instabilities in neutron stars  

SciTech Connect (OSTI)

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

342

Non-Employee Static Magnetic Field Questionnaire  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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.

343

Magnetic field exposure among utility workers  

SciTech Connect (OSTI)

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

344

3-Axis Magnetic Sensor Hybrid The Honeywell HMC2003 is a high sensitivity, three-axis magnetic sensor hybrid  

E-Print Network [OSTI]

3-Axis Magnetic Sensor Hybrid HMC2003 The Honeywell HMC2003 is a high sensitivity, three-axis magnetic sensor hybrid assembly used to measure low magnetic field strengths. Honeywell's most sensitive product excellence and performance by introducing innovative solid-state magnetic sensor solutions

Kleinfeld, David

345

GROWTH OF A LOCALIZED SEED MAGNETIC FIELD IN A TURBULENT MEDIUM  

SciTech Connect (OSTI)

Turbulence dynamo deals with the amplification of a seed magnetic field in a turbulent medium and has been studied mostly for uniform or spatially homogeneous seed magnetic fields. However, some astrophysical processes (e.g., jets from active galaxies, galactic winds, or ram-pressure stripping in galaxy clusters) can provide localized seed magnetic fields. In this paper, we numerically study amplification of localized seed magnetic fields in a turbulent medium. Throughout the paper, we assume that the driving scale of turbulence is comparable to the size of the system. Our findings are as follows. First, turbulence can amplify a localized seed magnetic field very efficiently. The growth rate of magnetic energy density is as high as that for a uniform seed magnetic field. This result implies that magnetic field ejected from an astrophysical object can be a viable source of a magnetic field in a cluster. Second, the localized seed magnetic field disperses and fills the whole system very fast. If turbulence in a system (e.g., a galaxy cluster or a filament) is driven at large scales, we expect that it takes a few large-eddy turnover times for the magnetic field to fill the whole system. Third, growth and turbulence diffusion of a localized seed magnetic field are also fast in high magnetic Prandtl number turbulence. Fourth, even in decaying turbulence, a localized seed magnetic field can ultimately fill the whole system. Although the dispersal rate of the magnetic field is not fast in purely decaying turbulence, it can be enhanced by an additional forcing.

Cho, Jungyeon; Yoo, Hyunju, E-mail: jcho@cnu.ac.kr [Department of Astronomy and Space Science, Chungnam National University, Daejeon (Korea, Republic of)

2012-11-10T23:59:59.000Z

346

Determining the exchange parameters of spin-1 metal-organic molecular magnets in pulsed magnetic fields  

SciTech Connect (OSTI)

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

347

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

348

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

349

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

350

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

351

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

352

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

353

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

354

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

355

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

356

Response of plastic scintillators in magnetic fields  

SciTech Connect (OSTI)

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

357

Improved Magnetic Field Generation Efficiency and Higher Temperature Spheromak Plasmas  

SciTech Connect (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.

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

358

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

359

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

360

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

Note: This page contains sample records for the topic "high magnetic fields" 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

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

362

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

363

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

364

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

365

Crystal-Field Splitting and Giant Negative Magnetization in  

SciTech Connect (OSTI)

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

366

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

367

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

368

High Temperature, Permanent Magnet Biased Magnetic Bearings  

E-Print Network [OSTI]

performance, high speed and high temperature applications like space vehicles, jet engines and deep sea equipment. The bearing system had a target design to carry a load equal to 500 lb-f (2225N). Another objective was to design and build a test rig fixture...

Gandhi, Varun R.

2010-07-14T23:59:59.000Z

369

Interaction of magnetic resonators studied by the magnetic field enhancement  

SciTech Connect (OSTI)

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

370

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

371

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

SciTech Connect (OSTI)

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

372

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

373

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

374

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

375

Hig Resolution Seismometer Insensitive to Extremely Strong Magnetic Fields  

SciTech Connect (OSTI)

A highly sensitive broadband seismic sensor has been developed successfully to be used in beam focusing systems of particale accelerators. The sensor is completely insensitive to extremely strong magnetic fields and to hard radiation conditions that exist at the place of their installation. A unique remote sensor calibration method has been invented and implemented. Several such sensors were sold to LAPP (LAPP-IN2P3/CNRS-Université de Savoie; Laboratoire d'Annecy-le-Vieux de Physique des Particules)

Abramovich, Igor A

2009-07-14T23:59:59.000Z

376

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

377

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

378

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

379

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

380

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 "high magnetic fields" 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

Two-dimensional oscillator in a magnetic field  

SciTech Connect (OSTI)

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

382

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

383

Dispersion relation and growth rate in a Cherenkov free electron laser: Finite axial magnetic field  

SciTech Connect (OSTI)

A theoretical analysis is presented for dispersion relation and growth rate in a Cherenkov free electron laser with finite axial magnetic field. It is shown that the growth rate and the resonance frequency of Cherenkov free electron laser increase with increasing axial magnetic field for low axial magnetic fields, while for high axial magnetic fields, they go to a saturation value. The growth rate and resonance frequency saturation values are exactly the same as those for infinite axial magnetic field approximation. The effects of electron beam self-fields on growth rate are investigated, and it is shown that the growth rate decreases in the presence of self-fields. It is found that there is an optimum value for electron beam density and Lorentz relativistic factor at which the maximum growth rate can take place. Also, the effects of velocity spread of electron beam are studied and it is found that the growth rate decreases due to the electron velocity spread.

Kheiri, Golshad; Esmaeilzadeh, Mahdi [Department of Physics, Iran University of Science and Technology, Tehran 16844 (Iran, Islamic Republic of)] [Department of Physics, Iran University of Science and Technology, Tehran 16844 (Iran, Islamic Republic of)

2013-12-15T23:59:59.000Z

384

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

385

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

386

MagLab - MagLab Dictionary: Magnetic Field (Transcript)  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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...

387

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

388

Enhanced density and magnetic fields in interstellar OH masers  

E-Print Network [OSTI]

Aims: We have observed the 6030 and 6035 MHz transitions of OH in high-mass star-forming regions to obtain magnetic field estimates in both maser emission and absorption. Methods: Observations were taken with the Effelsberg 100 m telescope. Results: Our observations are consistent with previous results, although we do detect a new 6030 MHz maser feature near -70 km/s in the vicinity of W3(OH). In absorption we obtain a possible estimate of -1.1 +/- 0.3 mG for the average line-of-sight component of the magnetic field in the absorbing OH gas in K3-50 and submilligauss upper limits for the line-of-sight field strength in DR 21 and W3. Conclusions: These results indicate that the magnetic field strength in the vicinity of OH masers is higher than that of the surrounding, non-masing material, which in turn suggests that the density of masing OH regions is higher than that of their surroundings.

Vincent L. Fish; Mark J. Reid; Karl M. Menten; Thushara Pillai

2006-08-04T23:59:59.000Z

389

High Energy Electron Confinement in a Magnetic Cusp Configuration  

E-Print Network [OSTI]

We report experimental results validating the concept that plasma confinement is enhanced in a magnetic cusp configuration when beta (plasma pressure/magnetic field pressure) is order of unity. This enhancement is required for a fusion power reactor based on cusp confinement to be feasible. The magnetic cusp configuration possesses a critical advantage: the plasma is stable to large scale perturbations. However, early work indicated that plasma loss rates in a reactor based on a cusp configuration were too large for net power production. Grad and others theorized that at high beta a sharp boundary would form between the plasma and the magnetic field, leading to substantially smaller loss rates. The current experiment validates this theoretical conjecture for the first time and represents critical progress toward the Polywell fusion concept which combines a high beta cusp configuration with an electrostatic fusion for a compact, economical, power-producing nuclear fusion reactor.

Park, Jaeyoung; Sieck, Paul E; Offermann, Dustin T; Skillicorn, Michael; Sanchez, Andrew; Davis, Kevin; Alderson, Eric; Lapenta, Giovanni

2014-01-01T23:59:59.000Z

390

Scaling Law for the Magnetic Field of the Planets Based on a Thermodynamic Model  

E-Print Network [OSTI]

A thermodynamic model for the generation of magnetic fields in the planets is proposed, considering crossed effects between gravitational and electric forces. The magnetic field of the Earth is estimated and found to be in agreement with the actual field. The ratio between the field of several planets and that of the Earth is calculated in the model and compared with the same ratio for the measured fields. These comparisons are found to be qualitatively consistent. Once the value of the magnetic field is calculated, the model is used to obtain the tilt of the magnetic dipole with respect to the rotation axis. This model can explain why Uranus and Neptune magnetic fields have higher quadrupole moment than the other magnetic fields of the Solar System and why Saturn, that has a highly axysymmetric field, has lower quadrupolar component. The model also explains the double peak of the magnetic field observed by Voyager 2 while recording the field of Neptune. The Earth paleomagnetic data are analysed and found to be consistent with the model, that predicts higher quadrupole components for the more tilted dipoles. A field is predicted for all the planets and satellites of the Solar System with enough mass. Objections are made to the theories that predict that this effect could not generate a field agreeing with the measured one.

F. X. Alvarez

2006-04-18T23:59:59.000Z

391

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

392

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

393

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

394

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

395

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

396

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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...

397

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

398

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

399

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

400

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

Note: This page contains sample records for the topic "high magnetic fields" 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

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

402

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

403

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

404

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

405

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

406

SCALING LAW FOR THE IMPACT OF MAGNET FRINGE FIELDS.  

SciTech Connect (OSTI)

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

407

MAGNETIC RESONANCE ELECTRICAL IMPEDANCE TOMOGRAPHY (MR-EIT): A new technique for high resolution conductivity imaging  

E-Print Network [OSTI]

MAGNETIC RESONANCE ELECTRICAL IMPEDANCE TOMOGRAPHY (MR-EIT): A new technique for high resolution potentials and the magnetic fields produced by the probing current are measured. Surface potentials are measured by using conventional electrical impedance tomography techniques and high resolution magnetic

Eyüboðlu, Murat

408

Primary beam steering due to field leakage from superconducting SHMS magnets  

DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

Simulations of the magnetic fields from the Super High Momentum Spectrometer in Hall C at Thomas Jefferson National Accelerator Facility show significant field leakage into the region of the primary beam line between the target and the beam dump. Without mitigation, these remnant fields will steer the unscattered beam enough to limit beam operations at small scattering angles. Presented here are magnetic field simulations of the spectrometer magnets and a solution using optimal placement of a minimal amount of shielding iron around the beam line.

Moore, M.H.; Waidyawansa, B.P.; Covrig, S.; Carlini, R.; Benesch, J.

2014-11-01T23:59:59.000Z

409

Primary Beam Steering Due to Field Leakage from Superconducting SHMS Magnets  

E-Print Network [OSTI]

Simulations of the magnetic fields from the Super High Momentum Spectrometer in Hall C at Thomas Jefferson National Accelerator Facility show significant field leakage into the region of the primary beam line between the target and the beam dump. Without mitigation, these remnant fields will steer the unscattered beam enough to limit beam operations at small scattering angles. Presented here are magnetic field simulations of the spectrometer magnets and a solution using optimal placement of a minimal amount of shielding iron around the beam line.

Michael H. Moore; Buddhini P. Waidyawansa; Silviu Covrig; Roger Carlini; Jay Benesch

2014-06-30T23:59:59.000Z

410

A loss-based, magnetic field sensor implemented in a ferrofluid infiltrated microstructured polymer optical fiber  

SciTech Connect (OSTI)

We report an in-fiber magnetic field sensor based on magneto-driven optical loss effects, while being implemented in a ferrofluid infiltrated microstructured polymer optical fiber. We demonstrate that magnetic field flux changes up to 2000 gauss can be detected when the magnetic field is applied perpendicular to the fiber axis. In addition, the sensor exhibits high polarization sensitivity for the interrogated wavelengths, providing the possibility of both field flux and direction measurements. The underlying physical and guidance mechanisms of this sensing transduction are further investigated using spectrophotometric, light scattering measurements, and numerical simulations, suggesting photonic Hall effect as the dominant physical, transducing mechanism.

Candiani, A. [Foundation for Research and Technology-Hellas (FORTH), Institute of Electronic Structure and Laser (IESL), Heraklion 70013 Greece (Greece); Department of Information Engineering (DII), University of Parma, Parma 43124 (Italy); Argyros, A.; Leon-Saval, S. G.; Lwin, R. [Institute of Photonics and Optical Science (IPOS), School of Physics, The University of Sydney, Sydney (Australia); Selleri, S. [Department of Information Engineering (DII), University of Parma, Parma 43124 (Italy); Pissadakis, S., E-mail: pissas@iesl.forth.gr [Foundation for Research and Technology-Hellas (FORTH), Institute of Electronic Structure and Laser (IESL), Heraklion 70013 Greece (Greece)

2014-03-17T23:59:59.000Z

411

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

412

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

413

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.

414

A variable-field permanent-magnet dipole for accelerators  

SciTech Connect (OSTI)

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

415

A variable-field permanent-magnet dipole for accelerators  

SciTech Connect (OSTI)

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

416

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

417

Abrupt Longitudinal Magnetic Field Changes in Flaring Active Regions  

Science Journals Connector (OSTI)

We characterize the changes in the longitudinal photospheric magnetic field during 38 X-class and 39 M-class flares within 65° of disk center using 1 minute GONG magnetograms. In all 77 cases, we identify at least one site in the flaring active region where clear, permanent, stepwise field changes occurred. The median duration of the field changes was about 15 minutes and was approximately equal for X-class and for M-class flares. The absolute values of the field changes ranged from the detection limit of ~10 G to as high as ~450 G in two exceptional cases. The median value was 69 G. Field changes were significantly stronger for X-class than for M-class flares and for limb flares than for disk-center flares. Longitudinal field changes less than 100 G tended to decrease longitudinal field strengths, both close to disk center and close to the limb, while field changes greater than 100 G showed no such pattern. Likewise, longitudinal flux strengths tended to decrease during flares. Flux changes, particularly net flux changes near disk center, correlated better than local field changes with GOES peak X-ray flux. The strongest longitudinal field and flux changes occurred in flares observed close to the limb. We estimate the change of Lorentz force associated with each flare and find that this is large enough in some cases to power seismic waves. We find that longitudinal field decreases would likely outnumber increases at all parts of the solar disk within 65° of disk center, as in our observations, if photospheric field tilts increase during flares as predicted by Hudson et al.

G. J. D. Petrie; J. J. Sudol

2010-01-01T23:59:59.000Z

418

ABRUPT LONGITUDINAL MAGNETIC FIELD CHANGES IN FLARING ACTIVE REGIONS  

SciTech Connect (OSTI)

We characterize the changes in the longitudinal photospheric magnetic field during 38 X-class and 39 M-class flares within 65{sup 0} of disk center using 1 minute GONG magnetograms. In all 77 cases, we identify at least one site in the flaring active region where clear, permanent, stepwise field changes occurred. The median duration of the field changes was about 15 minutes and was approximately equal for X-class and for M-class flares. The absolute values of the field changes ranged from the detection limit of {approx}10 G to as high as {approx}450 G in two exceptional cases. The median value was 69 G. Field changes were significantly stronger for X-class than for M-class flares and for limb flares than for disk-center flares. Longitudinal field changes less than 100 G tended to decrease longitudinal field strengths, both close to disk center and close to the limb, while field changes greater than 100 G showed no such pattern. Likewise, longitudinal flux strengths tended to decrease during flares. Flux changes, particularly net flux changes near disk center, correlated better than local field changes with GOES peak X-ray flux. The strongest longitudinal field and flux changes occurred in flares observed close to the limb. We estimate the change of Lorentz force associated with each flare and find that this is large enough in some cases to power seismic waves. We find that longitudinal field decreases would likely outnumber increases at all parts of the solar disk within 65{sup 0} of disk center, as in our observations, if photospheric field tilts increase during flares as predicted by Hudson et al.

Petrie, G. J. D. [National Solar Observatory, 950 N. Cherry Avenue, Tucson, AZ 85719 (United States); Sudol, J. J. [West Chester University, West Chester, PA 19383 (United States)

2010-12-01T23:59:59.000Z

419

Spontaneous and field-induced magnetic transitions in YBaCo2O5.5  

SciTech Connect (OSTI)

A detailed study of magnetic properties of cobaltite YBaCo{sub 2}O{sub 5.5} has been performed in high (up to 35 T) magnetic fields and under hydrostatic pressure up to 0.8 GPa. The temperatures of paramagnet-ferromagnet (PM-FM) and ferromagnet-antiferromagnet (FM-AF) phase transitions and their pressure derivatives have been determined. It has been revealed that in the compound with yttrium, in contrast to those with magnetic rare earth atoms, the AF-FM field-induced magnetic phase transition is accompanied by a considerable field hysteresis below 240 K, and the magnetic field of 35 T is not sufficient to complete this transition at low temperatures. The hysteresis value depends on the magnetic field sweep rate, which considered as an evidence of magnetic viscosity that is especially strong in the region of coexistence of the FM and AF phases. High values of susceptibility for the field-induced FM phase show that Co spin state in these compounds changes in strong magnetic field.

Bobrovskii, Vladimir [Institute of Metal Physics, Russia; Kazantsev, Vadim [Institute of Metal Physics, Russia; Mirmelstein, Aleksey [Institute of Metal Physics, Russia; Mushnikov, Nikolai [Institute of Metal Physics, Russia; Proskurnina, Natalia [Institute of Metal Physics, Russia; Voronin, Vladimir [Institute of Metal Physics, Russia; Pomjakushina, Ekaterina [Paul Scherrer Institut, Villigen, Switzerland; Conder, Kazimierz [Paul Scherrer Institut, Villigen, Switzerland; Podlesnyak, Andrey A [ORNL

2009-01-01T23:59:59.000Z

420

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

Note: This page contains sample records for the topic "high magnetic fields" 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

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

422

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

423

The role of magnetic fields in hyperon stars  

SciTech Connect (OSTI)

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

424

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

425

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

426

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

427

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

SciTech Connect (OSTI)

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

428

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

SciTech Connect (OSTI)

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

429

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

430

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

431

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

432

Phase transitions in quark matter under strong magnetic fields  

SciTech Connect (OSTI)

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

433

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

434

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

435

Lithium and magnetic fields in giants. HD 232862 : a magnetic and lithium-rich giant star  

E-Print Network [OSTI]

We report the detection of an unusually high lithium content in HD 232862, a field giant classified as a G8II star, and hosting a magnetic field. With the spectropolarimeters ESPaDOnS at CFHT and NARVAL at TBL, we have collected high resolution and high signal-to-noise spectra of three giants : HD 232862, KU Peg and HD 21018. From spectral synthesis we have inferred stellar parameters and measured lithium abundances that we have compared to predictions from evolutionary models. We have also analysed Stokes V signatures, looking for a magnetic field on these giants. HD 232862, presents a very high abundance of lithium (ALi = 2.45 +/- 0.25 dex), far in excess of the theoretically value expected at this spectral type and for this luminosity class (i.e, G8II). The evolutionary stage of HD 232862 has been precised, and it suggests a mass in the lower part of the [1.0 Msun ; 3.5 Msun ] mass interval, likely 1.5 to 2.0 solar mass, at the bottom of the Red Giant Branch. Besides, a time variable Stokes V signature has...

Lèbre, A; Nascimento, J D do; Konstantinova-Antova, R; Kolev, D; Aurière, M; De Laverny, P; De Medeiros, J R

2009-01-01T23:59:59.000Z

436

PROTOSTELLAR DISK FORMATION ENABLED BY WEAK, MISALIGNED MAGNETIC FIELDS  

SciTech Connect (OSTI)

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

437

High-field remanence properties of synthetic and natural submicrometre haematites and goethites: significance  

E-Print Network [OSTI]

High-field remanence properties of synthetic and natural submicrometre haematites and goethites September 2004 Editor: V. Courtillot Abstract Haematite and goethite are significant magnetic components both of marine and terrestrial sediments. Variable magnetic behaviour in haematite and goethite has

438

Plasma-satellite interaction driven magnetic field perturbations  

SciTech Connect (OSTI)

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

439

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

440

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

Note: This page contains sample records for the topic "high magnetic fields" 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.


441

Observation of magnetic field lines in the vicinity of a superconductor with the naked eye  

E-Print Network [OSTI]

Meissner effect and pinning effect are clearly observed with the naked eye. A GdBaCuO high-temperature superconductor (HTS) disk fabricated by Nippon Steel Corporation, a 100mm cubic NdFeB sintered magnet, and iron wires coated by colored are used. When the HTS is put in the magnetic field of the magnet, it can be observed by the wires that the magnetic field lines are excluded from the superconductor (Meissner effect) as well as are pinned in the superconductor (pinning effect).

Yoshihiko Saito

2008-05-26T23:59:59.000Z

442

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

443

Analysis of magnetic fields produced far from electric power lines  

SciTech Connect (OSTI)

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

444

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

445

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

446

Magnetic field measurement of superconducting dipolemagnets with harmonic coil and Hall probe  

SciTech Connect (OSTI)

Magnetic field measurements and field analyses of 1-m long superconducting dipole magnets fabricated at the National Laboratory for High Energy Physics (KEK) have been carried out using a harmonic coil with the bucking scheme. Conditions of the data acquisition are optimized to achieve the accurate and efficient measurements. Not only in the steady state of the magnet excitation by constant currents, but also on the way the excite current increases until the magnet quenches the field measurements have been tried, and the results are discussed in this paper on the possibility of the {open_quotes}on-the-fly{close_quotes} measurement using a harmonic coil. Some results on the so-called remnant field of the magnets measured with a Hall probe are also described.

Nakai, Hirotaka; Kabe, Atsushi; Terashima, Akio [National Lab. for High Energy Physics, Tsukuba-shi, Ibaraki-ken (Japan)] [and others

1996-12-31T23:59:59.000Z

447

5 - High temperature superconductor (HTS) magnets  

Science Journals Connector (OSTI)

Abstract: At the time of writing, high temperature superconducting magnets have not fulfilled their early promise, mainly because of the difficulties in getting these reactive and brittle ceramics into wire form and, consequently, their expense. However, for some niche applications, HTS magnets have been developed. In this chapter, the author outlines his experience of building four such systems after introductory discussions about superconducting magnets in general and design considerations. The recent commercial availability of so-called second-generation (2G) coated conductors opens up a more promising scenario, provided the cost can come down. This scenario is discussed and some conclusions are drawn.

H. Jones

2012-01-01T23:59:59.000Z

448

Los Alamos achieves world-record pulsed magnetic field  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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.

449

Analysis of Reccurent Patterns in Toroidal Magnetic Fields  

SciTech Connect (OSTI)

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

450

VELOCITY AND MAGNETIC FIELD DISTRIBUTION IN A FORMING PENUMBRA  

SciTech Connect (OSTI)

We present results from the analysis of high-resolution spectropolarimetric and spectroscopic observations of the solar photosphere and chromosphere, obtained shortly before the formation of a penumbra in one of the leading polarity sunspots of NOAA active region 11490. The observations were performed at the Dunn Solar Telescope of the National Solar Observatory on 2012 May 28, using the Interferometric Bidimensional Spectrometer. The data set is comprised of a 1 hr time sequence of measurements in the Fe I 617.3 nm and Fe I 630.25 nm lines (full Stokes polarimetry) and in the Ca II 854.2 nm line (Stokes I only). We perform an inversion of the Fe I 630.25 nm Stokes profiles to derive magnetic field parameters and the line-of-sight (LOS) velocity at the photospheric level. We characterize chromospheric LOS velocities by the Doppler shift of the centroid of the Ca II 854.2 nm line. We find that, before the formation of the penumbra, an annular zone of 3''-5'' width is visible around the sunspot. In the photosphere, we find that this zone is characterized by an uncombed structure of the magnetic field although no visible penumbra has formed yet. We also find that the chromospheric LOS velocity field shows several elongated structures characterized by downflow and upflow motions in the inner and outer parts of the annular zone, respectively.

Romano, P.; Guglielmino, S. L. [INAF-Osservatorio Astrofisico di Catania, Via S. Sofia 78, I-95125 Catania (Italy); Frasca, D.; Zuccarello, F. [Dipartimento di Fisica e Astronomia-Sezione Astrofisica, Universita di Catania, Via S. Sofia 78, I-95125 Catania (Italy); Ermolli, I. [INAF-Osservatorio Astronomico di Roma, Via Frascati 33, I-00040 Monte Porzio Catone (Italy); Tritschler, A.; Reardon, K. P., E-mail: prom@oact.inaf.it [National Solar Observatory/Sacramento Peak, P.O. Box 62, Sunspot, NM 88349-0062 (United States)

2013-07-01T23:59:59.000Z

451

Induction of c-fos Gene Expression by Exposure to a Static Magnetic Field in HeLaS3 Cells  

Science Journals Connector (OSTI)

...Rutqvist L. E., Ahlbom A. Magnetic fields and breast cancer in Swedish adults residing near high-voltage power lines. Epidemiology, 9: 392-397...power-line frequency electric and magnetic fields. NIEHS Working Group Report...

Masahiro Hiraoka; Junji Miyakoshi; Yu P. Li; Bokshil Shung; Hiraku Takebe; and Mitsuyuki Abe

1992-12-01T23:59:59.000Z

452

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

453

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

454

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

455

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

SciTech Connect (OSTI)

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

456

CALCULATION OF PULSED KICKER MAGNETIC FIELD ATTENUATION INSIDE BEAM CHAMBERS  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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

457

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

458

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

459

Design considerations for a large aperture high field superconducting dipole  

SciTech Connect (OSTI)

The final phase of the Fermilab upgrade proposal calls for a new ring of superconducting magnets to be placed in the existing Main Accelerator tunnel. The goal of this design study is to specify a high field dipole (HFD) that is capable of supporting fixed target operation (ramping, resonant extraction) at a field of 6.6T (1.5 Tev) and colliding beam physics at 8.0T (1.8 Tev). The magnetic field quality at high field is set by the large amplitude orbits associated with resonant extraction. The field quality must therefore be at least as good as the existing Tevatron magnets which fulfill these criteria. The high fields and large aperture of this magnet result in large forces on the coil and collar assemblies. Therefore, the cold mass design must be able to sustain these forces while providing sufficient cooling to the coils during 4.2 K fixed target operation, and a minimum heat load during 1.8 K collider operation. The design work is still in progress but a cosine-theta, cold-iron dipole with a 70mm inner diameter coil has been tentatively adopted. This report presents details on the conductor and cable parameters, coil cross-section, projected manufacturing tolerances, iron yoke design, and cold mass assembly. 4 refs., 5 figs., 1 tab.

Harfoush, F.; Ankenbrandt, C.; Harrison, M.; Kerby, J.; Koepke, K.; Mantsch, P.; Nicol, T.; Riddiford, A.; Theilacker, J.

1989-03-01T23:59:59.000Z

460

THE LARGE-SCALE MAGNETIC FIELDS OF ADVECTION-DOMINATED ACCRETION FLOWS  

SciTech Connect (OSTI)

We calculate the advection/diffusion of the large-scale magnetic field threading an advection-dominated accretion flow (ADAF) and find that the magnetic field can be dragged inward by the accretion flow efficiently if the magnetic Prandtl number P{sub m}={eta}/{nu}{approx}1. This is due to the large radial velocity of the ADAF. It is found that the magnetic pressure can be as high as {approx}50% of the gas pressure in the inner region of the ADAF close to the black hole horizon, even if the external imposed homogeneous vertical field strength is {approx}< 5% of the gas pressure at the outer radius of the ADAF, which is caused by the gas in the ADAF plunging rapidly to the black hole within the marginal stable circular orbit. In the inner region of the ADAF, the accretion flow is significantly pressured in the vertical direction by the magnetic fields, and therefore its gas pressure can be two orders of magnitude higher than that in the ADAF without magnetic fields. This means that the magnetic field strength near the black hole is underestimated by assuming equipartition between magnetic and gas pressure with the conventional ADAF model. Our results show that the magnetic field strength of the flow near the black hole horizon can be more than one order of magnitude higher than that in the ADAF at {approx}3R{sub g} (R{sub g} = 2GM/c{sup 2}), which implies that the Blandford-Znajek mechanism could be more important than the Blandford-Payne mechanism for ADAFs. We find that the accretion flow is decelerated near the black hole by the magnetic field when the external imposed field is strong enough or the gas pressure of the flow is low at the outer radius, or both. This corresponds to a critical accretion rate, below which the accretion flow will be arrested by the magnetic field near the black hole for a given external imposed field. In this case, the gas may accrete as magnetically confined blobs diffusing through field lines in the region very close to the black hole horizon, similar to those in compact stars. Our calculations are also valid for the case that the inner ADAF connects to the outer cold thin disk at a certain radius. In this case, the advection of the external fields is quite inefficient in the outer thin disk due to its low radial velocity, and the field lines thread the disk almost vertically, while these field lines can be efficiently dragged inward by the radial motion of the inner ADAF.

Cao Xinwu, E-mail: cxw@shao.ac.cn [Key Laboratory for Research in Galaxies and Cosmology, Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Shanghai 200030 (China)

2011-08-20T23:59:59.000Z

Note: This page contains sample records for the topic "high magnetic fields" 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.


461

Transition from two-dimensional electron-hole to geminate-exciton photoluminescence in GaAs?AlxGa1?xAs heterostructures under a high in-plane magnetic field  

Science Journals Connector (OSTI)

We studied the evolution of the photoluminescence (PL) spectra in modulation-doped GaAs-based heterostructures (single quantum wells and heterojunctions) at TL=1.2K under a high magnetic field B (up to 33T), which was applied parallel to the two-dimensional electron gas (2DEG) layer. Under low in-plane fields, B?<7T, the radiative recombination of the photoexcited hole with the 2DEG gives rise to a broad PL band that shifts quadratically with B?. This band transforms into a narrow PL line whose peak energy E shifts linearly with B? in the range of 10–33T. The slope of the linear E(B) dependence was measured as ?ex=0.77±0.02meV?T in all the studied structures. The same linear slope is also measured in the PL spectra of bulk, undoped GaAs under high B. We thus attribute the sharp PL line observed in the doped heterostructures to magnetoexcitons that are photogenerated outside the 2DEG layer by a geminate formation process. The slope of the magnetoexciton energy dependence on B? is compared with that measured for unbound-electron–hole Landau level transitions under a perpendicular B?. The ratio of the measured slopes, ?ex??0?0.8, is found to be equal to the ratio of the reduced excitonic mass to the reduced cyclotron mass of GaAs.

B. M. Ashkinadze, E. Cohen, V. V. Rudenkov, P. C. M. Christianen, J. C. Maan, and L. N. Pfeiffer

2007-08-27T23:59:59.000Z

462

The magnetic field of the pre-main sequence Herbig Ae star HD 190073  

E-Print Network [OSTI]

The general context of this paper is the study of magnetic fields in the pre-main sequence intermediate mass Herbig Ae/Be stars. Magnetic fields are likely to play an important role in pre-main sequence evolution at these masses, in particular in controlling the gains and losses of stellar angular momentum. The particular aim of this paper is to announce the detection of a structured magnetic field in the Herbig Ae star HD 190073, and to discuss various scenarii for the geometry of the star, its environment and its magnetic field. We have used the ESPaDOnS spectropolarimeter at CFHT in 2005 and 2006 to obtain high-resolution and signal-to-noise circular polarization spectra which demonstrate unambiguously the presence of a magnetic field in the photosphere of this star. Nine circular polarization spectra were obtained, each one showing a clear Zeeman signature. This signature is suggestive of a magnetic field structured on large scales. The signature, which corresponds to a longitudinal magnetic field of 74+-...

Catala, C; Donati, J F; Wade, G A; Landstreet, J D; Böhm, T; Bouret, J C; Bagnulo, S; Folsom, C; Silvester, J

2006-01-01T23:59:59.000Z

463

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

464

MAGNETIZED GAS IN THE SMITH HIGH VELOCITY CLOUD  

SciTech Connect (OSTI)

We report the first detection of magnetic fields associated with the Smith High Velocity Cloud. We use a catalog of Faraday rotation measures toward extragalactic radio sources behind the Smith Cloud, new H I observations from the Robert C. Byrd Green Bank Telescope, and a spectroscopic map of H? from the Wisconsin H-Alpha Mapper Northern Sky Survey. There are enhancements in rotation measure (RM) of ?100 rad m{sup –2} which are generally well correlated with decelerated H? emission. We estimate a lower limit on the line-of-sight component of the field of ?8 ?G along a decelerated filament; this is a lower limit due to our assumptions about the geometry. No RM excess is evident in sightlines dominated by H I or H? at the velocity of the Smith Cloud. The smooth H? morphology of the emission at the Smith Cloud velocity suggests photoionization by the Galactic ionizing radiation field as the dominant ionization mechanism, while the filamentary morphology and high (?1 Rayleigh) H? intensity of the lower-velocity magnetized ionized gas suggests an ionization process associated with shocks due to interaction with the Galactic interstellar medium. The presence of the magnetic field may contribute to the survival of high velocity clouds like the Smith Cloud as they move from the Galactic halo to the disk. We expect these data to provide a test for magnetohydrodynamic simulations of infalling gas.

Hill, Alex S.; McClure-Griffiths, Naomi M. [CSIRO Astronomy and Space Science, Marsfield, NSW (Australia); Mao, S. A. [Department of Astronomy, University of Wisconsin-Madison, Madison, WI (United States); Benjamin, Robert A. [Department of Physics, University of Wisconsin-Whitewater, Whitewater, WI (United States); Lockman, Felix J., E-mail: alex.hill@csiro.au, E-mail: naomi.mcclure-griffiths@csiro.au, E-mail: mao@astro.wisc.edu, E-mail: benjamir@uww.edu, E-mail: jlockman@nrao.edu [National Radio Astronomy Observatory, Green Bank, WV (United States)

2013-11-01T23:59:59.000Z

465

CURRENT SHEETS FORMATION IN TANGLED CORONAL MAGNETIC FIELDS  

SciTech Connect (OSTI)

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

466

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

467

Bio-Med Variable Field MRI Project | Superconducting Magnet Division  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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

468

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

469

New approaches to thermoelectric cooling effects in magnetic fields  

SciTech Connect (OSTI)

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

470

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

471

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

472

EMDEX (Electric and Magnetic Field Digital EXposure) system manuals  

SciTech Connect (OSTI)

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

473

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

474

alternating magnetic fields: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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...

475

MagLab - Magnetic Field of a Solenoid Tutorial  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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...

476

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

477

Port hole perturbations to the magnetic field in MST  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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 ,...

478

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

479

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

480

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

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481

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

482

Parallel heat transport in integrable and chaotic magnetic fields  

SciTech Connect (OSTI)

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

483

Parallel heat transport in integrable and chaotic magnetic fields  

SciTech Connect (OSTI)

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

484

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

485

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

486

Thermoelectric effects in organic conductors in a strong magnetic field  

SciTech Connect (OSTI)

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

487

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

488

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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...

489

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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...

490

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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...

491

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

492

Theory of magnetic field line random walk in noisy reduced magnetohydrodynamic turbulence  

SciTech Connect (OSTI)

When a magnetic field consists of a mean part and fluctuations, the stochastic wandering of its field lines is often treated as a diffusive process. Under suitable conditions, a stable value is found for the mean square transverse displacement per unit parallel displacement relative to the mean field. Here, we compute the associated field line diffusion coefficient for a highly anisotropic 'noisy' reduced magnetohydrodynamic model of the magnetic field, which is useful in describing low frequency turbulence in the presence of a strong applied DC mean magnetic field, as may be found, for example, in the solar corona, or in certain laboratory devices. Our approach is nonperturbative, based on Corrsin's independence hypothesis, and makes use of recent advances in understanding factors that control decorrelation over a range of parameters described by the Kubo number. Both Bohm and quasilinear regimes are identified.

Ruffolo, D. [Department of Physics, Faculty of Science, Mahidol University, Bangkok 10400, Thailand and Thailand Center of Excellence in Physics, CHE, Ministry of Education, Bangkok 10400 (Thailand); Matthaeus, W. H. [Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716 (United States)

2013-01-15T23:59:59.000Z

493

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

494

Magnetism in pre-MS intermediate-mass stars and the fossil field hypothesis  

E-Print Network [OSTI]

Today, one of the greatest challenges concerning the Ap/Bp stars is to understand the origin of their slow rotation and their magnetic fields. The favoured hypothesis for the latter is the fossil field, which implies that the magnetic fields subsist throughout the different evolutionary phases, and in particular during the pre-main sequence phase. The existence of magnetic fields at the pre-main sequence phase is also required to explain the slow rotation of Ap/Bp stars. However, until recently, essentially no information was available about the magnetic properties of intermediate-mass pre-main sequence stars, the so-called Herbig Ae/Be stars. The new high-resolution spectropolarimeter ESPaDOnS, installed in 2005 at the Canada-France-Hawaii telescope, provided the capability necessary to perform surveys of the Herbig Ae/Be stars in order to investigate their magnetism and rotation. These investigations have resulted in the detection and/or confirmation of magnetic fields in 8 Herbig Ae/Be stars, ranging in mass from 2 to nearly 15 solar masses. In this contribution I will present the results of our survey, as well as their implications for the origin and evolution of the magnetic fields and rotation.

E. Alecian; G. A. Wade; C. Catala; C. Folsom; J. Grunhut; J. -F. Donati; P. Petit; S. Bagnulo; S. C. Marsden; J. Ramirez; J. D. Landstreet; T. Boehm; J. -C. Bouret; J. Silvester

2007-12-03T23:59:59.000Z

495

Influence of a constant magnetic field on the dispersion of surface magnetostatic waves in a structure consisting of ferrite and granular high-temperature superconductor  

Science Journals Connector (OSTI)

The dispersional properties of a surface magnetostatic wave (MSW) in a laminar structure consisting of ferrite film and a high-temperature superconducting (HTSC) layer are studied in detail. The propagation of...

V. A. Krakovskii; E. S. Kovalenko

1996-06-01T23:59:59.000Z

496

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