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1

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...

2

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.

3

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.

4

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.

5

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.

6

X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation  

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

X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print Wednesday, 25 November 2009 00:00 Magnetic...

7

Resonant amplification of vortex-core oscillations by coherent magnetic-field pulses  

E-Print Network [OSTI]

structure of magnetic vortex cores. Science 298, 577–580 (D. A. et al. Magnetic domain-wall logic. Science 309, 1688 (L. Magnetic domain-wall racetrack memory. Science 320, 190–

Yu, Young-Sang

2014-01-01T23:59:59.000Z

8

X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation  

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

X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print Magnetic thin-film nanostructures can exhibit a magnetic vortex state in which the magnetization vectors lie in the film plane and curl around in a closed loop. At the very center of the vortex, a small, stable core exists where the magnetization points either up or down out of the plane. Three years ago, the discovery of an easy core reversal mechanism at the ALS not only made the possibility of using such systems as magnetic memories much more realistic, it also initiated investigation of the core switching mechanism itself. Now, a Belgian-German-ALS collaboration has used high-resolution, time-resolved, magnetic x-ray microscopy to experimentally reveal the first step of the reversal process: the dynamic deformation of the vortex core. The group also measured a critical vortex velocity above which reversal occurs. Both these observations provide the first experimental support for the postulated reversal mechanism.

9

X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation  

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

X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print Magnetic thin-film nanostructures can exhibit a magnetic vortex state in which the magnetization vectors lie in the film plane and curl around in a closed loop. At the very center of the vortex, a small, stable core exists where the magnetization points either up or down out of the plane. Three years ago, the discovery of an easy core reversal mechanism at the ALS not only made the possibility of using such systems as magnetic memories much more realistic, it also initiated investigation of the core switching mechanism itself. Now, a Belgian-German-ALS collaboration has used high-resolution, time-resolved, magnetic x-ray microscopy to experimentally reveal the first step of the reversal process: the dynamic deformation of the vortex core. The group also measured a critical vortex velocity above which reversal occurs. Both these observations provide the first experimental support for the postulated reversal mechanism.

10

X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation  

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

X-Ray Imaging of the Dynamic X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print Wednesday, 25 November 2009 00:00 Magnetic thin-film nanostructures can exhibit a magnetic vortex state in which the magnetization vectors lie in the film plane and curl around in a closed loop. At the very center of the vortex, a small, stable core exists where the magnetization points either up or down out of the plane. Three years ago, the discovery of an easy core reversal mechanism at the ALS not only made the possibility of using such systems as magnetic memories much more realistic, it also initiated investigation of the core switching mechanism itself. Now, a Belgian-German-ALS collaboration has used high-resolution, time-resolved, magnetic x-ray microscopy to experimentally reveal the first step of the reversal process: the dynamic deformation of the vortex core. The group also measured a critical vortex velocity above which reversal occurs. Both these observations provide the first experimental support for the postulated reversal mechanism.

11

X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation  

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

X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print Magnetic thin-film nanostructures can exhibit a magnetic vortex state in which the magnetization vectors lie in the film plane and curl around in a closed loop. At the very center of the vortex, a small, stable core exists where the magnetization points either up or down out of the plane. Three years ago, the discovery of an easy core reversal mechanism at the ALS not only made the possibility of using such systems as magnetic memories much more realistic, it also initiated investigation of the core switching mechanism itself. Now, a Belgian-German-ALS collaboration has used high-resolution, time-resolved, magnetic x-ray microscopy to experimentally reveal the first step of the reversal process: the dynamic deformation of the vortex core. The group also measured a critical vortex velocity above which reversal occurs. Both these observations provide the first experimental support for the postulated reversal mechanism.

12

X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation  

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

X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print Magnetic thin-film nanostructures can exhibit a magnetic vortex state in which the magnetization vectors lie in the film plane and curl around in a closed loop. At the very center of the vortex, a small, stable core exists where the magnetization points either up or down out of the plane. Three years ago, the discovery of an easy core reversal mechanism at the ALS not only made the possibility of using such systems as magnetic memories much more realistic, it also initiated investigation of the core switching mechanism itself. Now, a Belgian-German-ALS collaboration has used high-resolution, time-resolved, magnetic x-ray microscopy to experimentally reveal the first step of the reversal process: the dynamic deformation of the vortex core. The group also measured a critical vortex velocity above which reversal occurs. Both these observations provide the first experimental support for the postulated reversal mechanism.

13

X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation  

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

X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print Magnetic thin-film nanostructures can exhibit a magnetic vortex state in which the magnetization vectors lie in the film plane and curl around in a closed loop. At the very center of the vortex, a small, stable core exists where the magnetization points either up or down out of the plane. Three years ago, the discovery of an easy core reversal mechanism at the ALS not only made the possibility of using such systems as magnetic memories much more realistic, it also initiated investigation of the core switching mechanism itself. Now, a Belgian-German-ALS collaboration has used high-resolution, time-resolved, magnetic x-ray microscopy to experimentally reveal the first step of the reversal process: the dynamic deformation of the vortex core. The group also measured a critical vortex velocity above which reversal occurs. Both these observations provide the first experimental support for the postulated reversal mechanism.

14

X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation  

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

X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print Magnetic thin-film nanostructures can exhibit a magnetic vortex state in which the magnetization vectors lie in the film plane and curl around in a closed loop. At the very center of the vortex, a small, stable core exists where the magnetization points either up or down out of the plane. Three years ago, the discovery of an easy core reversal mechanism at the ALS not only made the possibility of using such systems as magnetic memories much more realistic, it also initiated investigation of the core switching mechanism itself. Now, a Belgian-German-ALS collaboration has used high-resolution, time-resolved, magnetic x-ray microscopy to experimentally reveal the first step of the reversal process: the dynamic deformation of the vortex core. The group also measured a critical vortex velocity above which reversal occurs. Both these observations provide the first experimental support for the postulated reversal mechanism.

15

Low-amplitude magnetic vortex core reversal by non-linear interaction between azimuthal spin waves and the vortex gyromode  

SciTech Connect (OSTI)

We show, by experiments and micromagnetic simulations in vortex structures, that an active “dual frequency” excitation of both the sub-GHz vortex gyromode and multi-GHz spin waves considerably changes the frequency response of spin wave mediated vortex core reversal. Besides additional minima in the switching threshold, a significant broadband reduction of the switching amplitudes is observed, which can be explained by non-linear interaction between the vortex gyromode and the spin waves. We conclude that the well known frequency spectra of azimuthal spin waves in vortex structures are altered substantially, when the vortex gyromode is actively excited simultaneously.

Sproll, Markus; Noske, Matthias; Kammerer, Matthias; Dieterle, Georg; Weigand, Markus; Stoll, Hermann; Schütz, Gisela [Max Planck Institute for Intelligent Systems (formerly MPI for Metals Research), Heisenbergstr. 3, 70569 Stuttgart (Germany)] [Max Planck Institute for Intelligent Systems (formerly MPI for Metals Research), Heisenbergstr. 3, 70569 Stuttgart (Germany); Bauer, Hans; Gangwar, Ajay; Woltersdorf, Georg; Back, Christian H. [Department of Physics, University of Regensburg, Universitätsstr. 31, 93040 Regensburg (Germany)] [Department of Physics, University of Regensburg, Universitätsstr. 31, 93040 Regensburg (Germany)

2014-01-06T23:59:59.000Z

16

Tunable negligible-loss energy transfer between dipolar-coupled magnetic disks by stimulated vortex gyration  

E-Print Network [OSTI]

structure of magnetic vortex cores. Science 298, 577– Park,Magnetic vortex core observation in circular dots of Permalloy. Science

Jung, Hyunsung

2014-01-01T23:59:59.000Z

17

Symmetry breaking in the formation of magnetic vortex states in a permalloy nanodisk  

E-Print Network [OSTI]

structure of magnetic vortex cores. Science 298, 6. Fischer,Magnetic Material Center, National Institute for Materials Science (Magnetic vortex core observation in circular dots of Permalloy. Science

Im, Mi-Young

2014-01-01T23:59:59.000Z

18

Development of vortex state in circular magnetic nanodots: Theory and experiment RID A-9247-2009  

E-Print Network [OSTI]

magnetic vortex. The vortex-core diameter is controlled by competing magnetic energy contributions. For 20-nm-thick Fe dots, the values of the critical diameter (58-60 nm) and the vortex core (16-19 nm) are in very good agreement between the different...

Mejia-Lopez, J.; Altbir, D.; Landeros, P.; Escrig, J.; Romero, A. H.; Roshchin, Igor V.; Li, C-P; Fitzsimmons, M. R.; Batlle, X.; Schuller, Ivan K.

2010-01-01T23:59:59.000Z

19

Dynamic switching of the circulation in tapered magnetic nanodisks  

E-Print Network [OSTI]

spin structure of magnetic vortex cores. Science 298, 577 (Magnetic vortex core observation in circular dots of permalloy. Science

Uhlir, V.

2014-01-01T23:59:59.000Z

20

UBIQUITOUS SOLAR ERUPTIONS DRIVEN BY MAGNETIZED VORTEX TUBES  

SciTech Connect (OSTI)

The solar surface is covered by high-speed jets transporting mass and energy into the solar corona and feeding the solar wind. The most prominent of these jets have been known as spicules. However, the mechanism initiating these eruption events is still unknown. Using realistic numerical simulations we find that small-scale eruptions are produced by ubiquitous magnetized vortex tubes generated by the Sun's turbulent convection in subsurface layers. The swirling vortex tubes (resembling tornadoes) penetrate into the solar atmosphere, capture and stretch background magnetic field, and push the surrounding material up, generating shocks. Our simulations reveal complicated high-speed flow patterns and thermodynamic and magnetic structure in the erupting vortex tubes. The main new results are: (1) the eruptions are initiated in the subsurface layers and are driven by high-pressure gradients in the subphotosphere and photosphere and by the Lorentz force in the higher atmosphere layers; (2) the fluctuations in the vortex tubes penetrating into the chromosphere are quasi-periodic with a characteristic period of 2-5 minutes; and (3) the eruptions are highly non-uniform: the flows are predominantly downward in the vortex tube cores and upward in their surroundings; the plasma density and temperature vary significantly across the eruptions.

Kitiashvili, I. N.; Kosovichev, A. G. [Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305 (United States); Lele, S. K.; Mansour, N. N.; Wray, A. A., E-mail: irinasun@stanford.edu [Center for Turbulence Research, Stanford University, Stanford, CA 94305 (United States)

2013-06-10T23:59:59.000Z

Note: This page contains sample records for the topic "magnetic vortex core" 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

Polarization-selective vortex-core switching by tailored orthogonal Gaussian-pulse currents  

SciTech Connect (OSTI)

We experimentally demonstrate low-power-consumption vortex-core switching in magnetic nanodisks using tailored rotating magnetic fields produced with orthogonal and unipolar Gaussian-pulse currents. The optimal width of the orthogonal pulses and their time delay are found, from analytical and micromagnetic numerical calculations, to be determined only by the angular eigenfrequency {omega}{sub D} for a given vortex-state disk of polarization p, such that {sigma}=1/{omega}{sub D} and ?{Delta}t={pi}/2 p/{omega}{sub D} . The estimated optimal pulse parameters are in good agreement with the experimental results. This work lays a foundation for energy-efficient information recording in vortex-core cross-point architecture.

Jung, H.; Choi, Y. -S.; Yoo, M. -W.; Im, M. -Y.; Kim, S. -K.

2010-10-13T23:59:59.000Z

22

Memory-bit selection and recording by rotating fields in vortex-core cross-point architecture  

SciTech Connect (OSTI)

In one of our earlier studies [Appl. Phys. Lett. 92, 022509 (2008)], we proposed a concept of robust information storage, recording and readout, which can be implementaed in nonvolatile magnetic random-access memories and is based on the energetically degenerated twofold ground states of vortex-core magnetizations. In the present study, we experimentally demonstrate reliable memory-bit selection and information recording in vortex-core cross-point architecture, specifically using a two-by-two vortex-state disk array. In order to efficiently switch a vortex core positioned at the intersection of crossed electrodes, two orthogonal addressing electrodes are selected, and then two Gaussian pulse currents of optimal pulse width and time delay are applied. Such tailored pulse-type rotating magnetic fields which occurs only at the selected intersection is prerequisite for a reliable memory-bit selection and low-power-consumption recording of information in the existing cross-point architecture.

Yu, Y. -S.; Jung, H.; Lee, K. -S.; Fischer, P.; Kim, S. -K.

2010-10-21T23:59:59.000Z

23

Role of the core energy in the vortex Nernst effect  

Science Journals Connector (OSTI)

We present an analytical study of diamagnetism and transport in a film with superconducting phase fluctuations, formulated in terms of vortex dynamics within the Debye-Hückel approximation. We find that the diamagnetic and Nernst signals decay strongly with temperature in a manner that is dictated by the vortex core energy. Using the theory to interpret Nernst measurements of underdoped La2?xSrxCuO4 above the critical temperature regime, we obtain a considerably better fit to the data than a fit based on Gaussian order-parameter fluctuations. Our results indicate that the core energy in this system scales roughly with the critical temperature and is significantly smaller than expected from BCS theory. Furthermore, it is necessary to assume that the vortex mobility is much larger than the Bardeen-Stephen value in order to reconcile conductivity measurements with the same vortex picture. Therefore, either the Nernst signal is not due to fluctuating vortices, or vortices in underdoped La2?xSrxCuO4 have highly unconventional properties.

Gideon Wachtel and Dror Orgad

2014-11-11T23:59:59.000Z

24

Dynamics of Magnetized Vortex Tubes in the Solar Chromosphere  

E-Print Network [OSTI]

We use 3D radiative MHD simulations to investigate the formation and dynamics of small-scale (less than 0.5 Mm in diameter) vortex tubes spontaneously generated by turbulent convection in quiet-Sun regions with initially weak mean magnetic fields. The results show that the vortex tubes penetrate into the chromosphere and substantially affect the structure and dynamics of the solar atmosphere. The vortex tubes are mostly concentrated in intergranular lanes and are characterized by strong (near sonic) downflows and swirling motions that capture and twist magnetic field lines, forming magnetic flux tubes that expand with height and which attain magnetic field strengths ranging from 200 G in the chromosphere to more than 1 kG in the photosphere. We investigate in detail the physical properties of these vortex tubes, including thermodynamic properties, flow dynamics, and kinetic and current helicities, and conclude that magnetized vortex tubes provide an important path for energy and momentum transfer from the con...

Kitiashvili, I N; Mansour, N N; Wray, A A

2012-01-01T23:59:59.000Z

25

Argonne CNM Highlight: Biofunctionalized magnetic-vortex microdiscs for  

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

Biofunctionalized magnetic-vortex microdiscs for targeted cancer-cell destruction Biofunctionalized magnetic-vortex microdiscs for targeted cancer-cell destruction Magnetic microdisks Reflection optical microscope image of a dried suspension of the discs prepared via magnetron sputtering and optical lithography. Magnetic spin vortex Model of magnetic-vortex spin distribution in a disc. Users from Argonne's Materials Science Division and University of Chicago's Pritzker School of Medicine, working collaboratively on a user science project with CNM's Nanobio Interfaces Group, have discovered that nanostructured magnetic materials offer exciting avenues for probing cell mechanics, activating mechanosensitive ion channels, and advancing potential cancer therapies. Their new report describes an approach based on interfacing cells with lithographically defined microdiscs (1-micron

26

Vortex-vacancy interactions in two-dimensional easy-plane magnets G. M. Wysin  

E-Print Network [OSTI]

Vortex-vacancy interactions in two-dimensional easy-plane magnets G. M. Wysin Department of Physics of a magnetic vacancy site on a nearby magnetic vortex are analyzed on square, hexagonal and triangular lattices. When the vortex is centered on a vacancy, the critical anisotropies where the stable vortex structure

Wysin, Gary

27

Optical excitation of quasiparticle pairs in the vortex core of high- T sub c superconductors  

SciTech Connect (OSTI)

A far-infrared resonance has been observed in superconducting YBa{sub 2}Cu{sub 3}O{sub 7} thin films in the presence of high magnetic fields. It corresponds to the quasiparticle pair creation process inside the vortex core. The resonance frequency is {omega}{sub 0}=1.3{ital kT}{sub {ital c}}/{h bar} with a linewidth 1/{tau}{congruent}0.6{omega}. This value for {omega}{sub 0} implies, within BCS theory, a large energy gap in YBa{sub 2}Cu{sub 3}O{sub 7}.

Karraie, K.; Choi, E.J.; Dunmore, F.; Liu, S.H.; Drew, H.D. (Center for Superconductivity Research, Department of Physics, University of Maryland, College Park, Maryland 20742 (United States) Laboratory for Physical Sciences, College Park, Maryland 20740 (United States)); Li, Q.; Fenner, D.B. (Advanced Fuel Research, E. Hartford, Connecticut 06138 (United States)); Zhu, Y.D.; Zhang, F. (Department of Physics, University of Cincinnati, Cincinnati, Ohio 45221 (United States))

1992-07-06T23:59:59.000Z

28

Ubiquitous Solar Eruptions Driven by Magnetized Vortex Tubes  

E-Print Network [OSTI]

The solar surface is covered by high-speed jets transporting mass and energy into the solar corona and feeding the solar wind. The most prominent of these jets have been known as spicules. However, the mechanism initiating these eruptions events is still unknown. Using realistic numerical simulations we find that small-scale eruptions are produced by ubiquitous magnetized vortex tubes generated by the Sun's turbulent convection in subsurface layers. The swirling vortex tubes (resembling tornadoes) penetrate into the solar atmosphere, capture and stretch background magnetic field, and push surrounding material up, generating quasiperiodic shocks. Our simulations reveal a complicated high-speed flow patterns, and thermodynamic and magnetic structure in the erupting vortex tubes. We found that the eruptions are initiated in the subsurface layers and are driven by the high-pressure gradients in the subphotosphere and photosphere, and by the Lorentz force in the higher atmosphere layers.

Kitiashvili, I N; Lele, S K; Mansour, N N; Wray, A A

2013-01-01T23:59:59.000Z

29

Magnetic Vortex Dynamics Roman ANTOS1  

E-Print Network [OSTI]

background of the research topic and briefly list the analytical and experimental approaches dealing interest due to their possible applications in high density magnetic data storage,3) magnetic field sensors background of the research topic according to the description by Hubert and Schafer6) (§2) and briefly

Otani, Yoshichika

30

Magnetization reversal via single and double vortex states in submicron Permalloy ellipses P. Vavassori,1  

E-Print Network [OSTI]

Magnetization reversal via single and double vortex states in submicron Permalloy ellipses P University, Ithaca, New York, USA Received December 5, 2003; published 3 June 2004 The magnetization reversal of the magnetic field and to occur via the formation of one or two vortices; the one vortex state is nucleated

Metlushko, Vitali

31

Numerical Simulation of the Meso-? Scale Structure and Evolution of the 1977 Johnstown Flood. Part II: Inertially Stable Warm-Core Vortex and the Mesoscale Convective Complex  

Science Journals Connector (OSTI)

A mesoscale warm-core vortex associated with the mesoscale convective complex (MCC) that produced the 1977 Johnstown flood is examined using a three-dimensional nested-grid model simulation of the flood episode. In the simulation, the vortex ...

Da-Lin Zhang; J. Michael Fritsch

1987-09-01T23:59:59.000Z

32

Smart” Diblock Copolymers as Templates for Magnetic-Core...  

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

Smart” Diblock Copolymers as Templates for Magnetic-Core Gold-Shell Nanoparticle Synthesis. Smart” Diblock Copolymers as Templates for Magnetic-Core Gold-Shell...

33

Vortex Structure in Charged Condensate  

E-Print Network [OSTI]

We study magnetic fields in the charged condensate that we have previously argued should be present in helium-core white dwarf stars. We show that below a certain critical value the magnetic field is entirely expelled from the condensate, while for larger values it penetrates the condensate within flux-tubes that are similar to Abrikosov vortex lines; yet higher fields lead to the disruption of the condensate. We find the solution for the vortex lines in both relativistic and nonrelativistic theories that exhibit the charged condensation. We calculate the energy density of the vortex solution and the values of the critical magnetic fields. The minimum magnetic field required for vortices to penetrate the helium white dwarf cores ranges from roughly 10^7 to 10^9 Gauss. Fields of this strength have been observed in white dwarfs. We also calculate the London magnetic field due to the rotation of a dwarf star and show that its value is rather small.

Gabadadze, Gregory

2009-01-01T23:59:59.000Z

34

Vortex Structure in Charged Condensate  

E-Print Network [OSTI]

We study magnetic fields in the charged condensate that we have previously argued should be present in helium-core white dwarf stars. We show that below a certain critical value the magnetic field is entirely expelled from the condensate, while for larger values it penetrates the condensate within flux-tubes that are similar to Abrikosov vortex lines; yet higher fields lead to the disruption of the condensate. We find the solution for the vortex lines in both relativistic and nonrelativistic theories that exhibit the charged condensation. We calculate the energy density of the vortex solution and the values of the critical magnetic fields. The minimum magnetic field required for vortices to penetrate the helium white dwarf cores ranges from roughly 10^7 to 10^9 Gauss. Fields of this strength have been observed in white dwarfs. We also calculate the London magnetic field due to the rotation of a dwarf star and show that its value is rather small.

Gregory Gabadadze; Rachel A. Rosen

2009-05-14T23:59:59.000Z

35

Kelvin-Helmholtz instability in a current-vortex sheet at a 3D magnetic null  

SciTech Connect (OSTI)

We report here, for the first time, an observed instability of a Kelvin-Helmholtz nature occurring in a fully three-dimensional (3D) current-vortex sheet at the fan plane of a 3D magnetic null point. The current-vortex layer forms self-consistently in response to foot point driving around the spine lines of the null. The layer first becomes unstable at an intermediate distance from the null point, with the instability being characterized by a rippling of the fan surface and a filamentation of the current density and vorticity in the shear layer. Owing to the 3D geometry of the shear layer, a branching of the current filaments and vortices is observed. The instability results in a mixing of plasma between the two topologically distinct regions of magnetic flux on either side of the fan separatrix surface, as flux is reconnected across this surface. We make a preliminary investigation of the scaling of the system with the dissipation parameters. Our results indicate that the fan plane separatrix surface is an ideal candidate for the formation of current-vortex sheets in complex magnetic fields and, therefore, the enhanced heating and connectivity change associated with the instabilities of such layers.

Wyper, P. F. [School of Mathematics and Statistics, University of Sheffield, Sheffield S3 7RH (United Kingdom); Pontin, D. I. [Division of Mathematics, University of Dundee, Dundee DD1 4HN (United Kingdom)

2013-03-15T23:59:59.000Z

36

Study of Superconducting Fault Current Limiter Using Saturated Magnetic Core  

Science Journals Connector (OSTI)

This paper presents a saturated magnetic core superconducting current limiter (SCSFCL) operation simulation results using finite element technique. The superconducting current limiter uses BSCCO tape to produce m...

F. Fajoni; E. Ruppert; C. A. Baldan…

2014-11-01T23:59:59.000Z

37

Plasma resonance at low magnetic fields as a probe of vortex line meandering in layered superconductors  

Science Journals Connector (OSTI)

We consider the magnetic-field dependence of the plasma resonance frequency in pristine and in irradiated Bi2Sr2CaCu2O8 crystals near Tc. At low magnetic fields we relate linear in field corrections to the plasma frequency to the average distance between the pancake vortices in the neighboring layers (wandering length). We calculate the wandering length in the case of thermal wiggling of vortex lines, taking into account both Josephson and magnetic interlayer coupling of pancakes. Analyzing experimental data, we found that (i) the wandering length becomes comparable with the London penetration depth near Tc and (ii) at small melting fields (line liquid phase in this field range. We also found that pinning by columnar defects affects weakly the field dependence of the plasma resonance frequency near Tc.

L. N. Bulaevskii; A. E. Koshelev; V. M. Vinokur; M. P. Maley

2000-02-01T23:59:59.000Z

38

Plasma resonance at low magnetic fields as a probe of vortex line meandering in layered superconductors  

E-Print Network [OSTI]

We consider the magnetic field dependence of the plasma resonance frequency in pristine and in irradiated Bi$_2$Sr$_2$CaCu$_2$O$_8$ crystals near $T_c$. At low magnetic fields we relate linear in field corrections to the plasma frequency to the average distance between the pancake vortices in the neighboring layers (wandering length). We calculate the wandering length in the case of thermal wiggling of vortex lines, taking into account both Josephson and magnetic interlayer coupling of pancakes. Analyzing experimental data, we found that (i) the wandering length becomes comparable with the London penetration depth near T$_{c}$ and (ii) at small melting fields ($line liquid phase in this field range. We also found that pinning by columnar defects affects weakly the field dependence of the plasma resonance frequency near $T_c$.

L. N. Bulaevskii; A. E. Koshelev; V. M. Vinokur; M. P. Maley

1999-07-29T23:59:59.000Z

39

EFFECTS OF RESISTIVITY ON MAGNETIZED CORE-COLLAPSE SUPERNOVAE  

SciTech Connect (OSTI)

We studied the role of turbulent resistivity in the core-collapse of a strongly magnetized massive star, carrying out two-dimensional resistive-MHD simulations. Three cases with different initial strengths of magnetic field and rotation are investigated: (1) a strongly magnetized rotating core, (2) a moderately magnetized rotating core, and (3) a very strongly magnetized non-rotating core. In each case, one ideal-MHD model and two resistive-MHD models are computed. As a result of these computations, each model shows an eruption of matter assisted by magnetic acceleration (and also by centrifugal acceleration in the rotating cases). We found that resistivity attenuates the explosion in cases 1 and 2, while it enhances the explosion in case 3. We also found that in the rotating cases, the main mechanisms for the amplification of a magnetic field in the post-bounce phase are an outward advection of the magnetic field and a twisting of poloidal magnetic field lines by differential rotation, which are somewhat dampened down with the presence of resistivity. Although magnetorotational instability seems to occur in the rotating models, it plays only a minor role in magnetic field amplification. Another impact of resistivity is that on the aspect ratio. In the rotating cases, a large aspect ratio of the ejected matter, >2.5, attained in an ideal-MHD model is reduced to some extent in a resistive model. These results indicate that resistivity possibly plays an important role in the dynamics of strongly magnetized supernovae.

Sawai, H.; Suzuki, H. [Tokyo University of Science, Chiba 278-8510 (Japan)] [Tokyo University of Science, Chiba 278-8510 (Japan); Yamada, S. [Waseda University, Shinjuku, Tokyo 169-8555 (Japan)] [Waseda University, Shinjuku, Tokyo 169-8555 (Japan); Kotake, K. [National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588 (Japan)] [National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588 (Japan)

2013-02-10T23:59:59.000Z

40

MagLab - Magnetic Core Memory Tutorial  

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

grid is made up of wires. The purpose of the horizontal and vertical X and Y Address Lines is to direct current to a specific core. The purpose of the diagonal Sense Lines is to...

Note: This page contains sample records for the topic "magnetic vortex core" 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

PHYSICAL REVIEW B 85, 134414 (2012) Nonlinear motion of magnetic vortex cores during fast magnetic pulses  

E-Print Network [OSTI]

pulses Keiki Fukumoto* Japan Synchrotron Radiation Research Institute, Sayo, Hyogo 679-5198, Japan 351-0198, Japan Toyohiko Kinoshita Japan Synchrotron Radiation Research Institute, Sayo, Hyogo 679 Kuniaki Arai Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan

Otani, Yoshichika

42

Dynamic decay of a single vortex into vortex-antivortex pairs  

SciTech Connect (OSTI)

A variety of metastable states, including vortices, antivortices, and their combinations, is typical for magnetically soft, thin films and patterned structures. The physics of individual spin vortices in patterned structures has been rather extensively explored. In contrast, there are few studies of the vortex–antivortex–vortex (v-av-v) system, in part because the configuration is rather challenging to obtain experimentally. We demonstrate herein how a recently proposed resonant-spin-ordering technique can be used to induce the dynamic decay of a single vortex into v-av states in elongated elements. The approach is based on first driving the system from the linear regime of constant vortex gyrations to the non-linear regime of vortex-core reversals at a fixed excitation frequency, and then subsequently reducing the excitation field back to the linear regime. This procedure stabilizes the system into a v-av-v state that is completely decoupled from the initialization excitation frequency. The newly acquired state is stable in remanence. The dynamic response of this system is expected to demonstrate a number of collective modes, depending on the combination of the vortex core polarities, and/or the excitation field direction, and, hence, is of interest for future studies.

Lendínez, Sergi [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Universidad Barcelona, Departamento Fisica Fonamental, E-08028 Barcelona (Spain); Jain, Shikha; Novosad, Valentyn, E-mail: novosad@anl.gov; Fradin, Frank Y.; Pearson, John E. [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Tejada, Javier [Universidad Barcelona, Departamento Fisica Fonamental, E-08028 Barcelona (Spain); Bader, Samuel D. [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439 (United States)

2014-05-07T23:59:59.000Z

43

MISALIGNMENT OF MAGNETIC FIELDS AND OUTFLOWS IN PROTOSTELLAR CORES  

SciTech Connect (OSTI)

We present results of {lambda}1.3 mm dust-polarization observations toward 16 nearby, low-mass protostars, mapped with {approx}2.''5 resolution at CARMA. The results show that magnetic fields in protostellar cores on scales of {approx}1000 AU are not tightly aligned with outflows from the protostars. Rather, the data are consistent with scenarios where outflows and magnetic fields are preferentially misaligned (perpendicular), or where they are randomly aligned. If one assumes that outflows emerge along the rotation axes of circumstellar disks, and that the outflows have not disrupted the fields in the surrounding material, then our results imply that the disks are not aligned with the fields in the cores from which they formed.

Hull, Charles L. H.; Plambeck, Richard L.; Bower, Geoffrey C.; Heiles, Carl; Meredith Hughes, A. [Astronomy Department and Radio Astronomy Laboratory, University of California, Berkeley, CA 94720-3411 (United States); Bolatto, Alberto D.; Jameson, Katherine; Mundy, Lee; Pound, Marc W. [Astronomy Department and Laboratory for Millimeter-wave Astronomy, University of Maryland, College Park, MD 20742 (United States); Carpenter, John M.; Lamb, James W.; Pillai, Thushara [Department of Astronomy, California Institute of Technology, 1200 E. California Blvd., MC 249-17, Pasadena, CA 91125 (United States); Crutcher, Richard M.; Hakobian, Nicholas S.; Kwon, Woojin; Looney, Leslie W. [Department of Astronomy, University of Illinois at Urbana-Champaign, 1002 W Green Street, Urbana, IL 61801 (United States); Fiege, Jason D.; Franzmann, Erica [Department of Physics and Astronomy, University of Manitoba, Winnipeg, MB R3T 2N2 (Canada); Houde, Martin [Department of Physics and Astronomy, University of Western Ontario, London, ON N6A 3K7 (Canada); Matthews, Brenda C., E-mail: chat@astro.berkeley.edu [Department of Physics and Astronomy, University of Victoria, 3800 Finnerty Rd., Victoria, BC V8P 5C2 (Canada); and others

2013-05-10T23:59:59.000Z

44

Pulsed Magnetic Welding for Advanced Core and Cladding Steel  

SciTech Connect (OSTI)

To investigate a solid-state joining method, pulsed magnetic welding (PMW), for welding the advanced core and cladding steels to be used in Generation IV systems, with a specific application for fuel pin end-plug welding. As another alternative solid state welding technique, pulsed magnetic welding (PMW) has not been extensively explored on the advanced steels. The resultant weld can be free from microstructure defects (pores, non-matallic inclusions, segregation of alloying elements). More specifically, the following objectives are to be achieved, 1) To design a suitable welding apparatus fixture, and optimize welding parameters for repeatable and acceptable joining of the fuel pin end-plug. The welding will be evaluated using tensile tests for lap joint weldments and helium leak tests for the fuel pin end-plug. 2) investigate the microstructural and mechanical properties changes in PMW weldments of proposed advanced core and cladding alloys. 3) Simulate the irradiation effects on the PWM weldments using ion irradiation.

Cao, Guoping; Yang, Yong

2013-12-19T23:59:59.000Z

45

Tailoring magnetic properties of core/shell nanoparticles and Shouheng Sun  

E-Print Network [OSTI]

in electromagnetic and permanent magnetic applications.10,11 In such a system, the intimate contact be- tween the core and shell leads to effective exchange coupling and therefore cooperative magnetic switching coupled and magneti- zation of both core and shell reverses cooperatively. As a result, the magnetic

Liu, J. Ping

46

Z2 index for gapless fermionic modes in the vortex core of three-dimensional paired Dirac fermions  

Science Journals Connector (OSTI)

We consider the gapless modes along the vortex line of the fully gapped, momentum independent paired states of three-dimensional Dirac fermions. For this, we require the solution of fermion zero modes of the corresponding two-dimensional problem in the presence of a point vortex, in the plane perpendicular to the vortex line. Based on the spectral symmetry requirement for the existence of the zero mode, we identify the appropriate generalized Jackiw-Rossi Hamiltonians for different paired states. A four-dimensional generalized Jackiw-Rossi Hamiltonian possesses spectral symmetry with respect to an antiunitary operator, and gives rise to a single zero mode only for the odd vorticity, which is formally described by a Z2 index. In the presence of generic perturbations such as chemical potential, Dirac mass, and Zeeman couplings, the associated two-dimensional problem for the odd parity topological superconducting state maps onto two copies of generalized Jackiw-Rossi Hamiltonian, and consequently an odd vortex binds two Majorana fermions. In contrast, there are no zero-energy states for the topologically trivial s-wave superconductor in the presence of any chiral symmetry breaking perturbation in the particle-hole channel, such as regular Dirac mass. We show that the number of one-dimensional dispersive modes along the vortex line is also determined by the index of the associated two-dimensional problem. For an axial superfluid state in the presence of various perturbations, we discuss the consequences of the Z2 index on the anomaly equations.

Bitan Roy and Pallab Goswami

2014-04-14T23:59:59.000Z

47

Control of magnetic vortex chirality in square ring micromagnets Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556 and Materials Science  

E-Print Network [OSTI]

Control of magnetic vortex chirality in square ring micromagnets A. Libála Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556 and Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 M. Grimsditch Materials Science Division, Argonne National Laboratory

Metlushko, Vitali

48

MAGNETIZATION OF CLOUD CORES AND ENVELOPES AND OTHER OBSERVATIONAL CONSEQUENCES OF RECONNECTION DIFFUSION  

SciTech Connect (OSTI)

Recent observational results for magnetic fields in molecular clouds reviewed by Crutcher seem to be inconsistent with the predictions of the ambipolar diffusion theory of star formation. These include the measured decrease in mass to flux ratio between envelopes and cores, the failure to detect any self-gravitating magnetically subcritical clouds, the determination of the flat probability distribution function (PDF) of the total magnetic field strengths implying that there are many clouds with very weak magnetic fields, and the observed scaling B{proportional_to}{rho}{sup 2/3} that implies gravitational contraction with weak magnetic fields. We consider the problem of magnetic field evolution in turbulent molecular clouds and discuss the process of magnetic field diffusion mediated by magnetic reconnection. For this process that we termed 'reconnection diffusion', we provide a simple physical model and explain that this process is inevitable in view of the present-day understanding of MHD turbulence. We address the issue of the expected magnetization of cores and envelopes in the process of star formation and show that reconnection diffusion provides an efficient removal of magnetic flux that depends only on the properties of MHD turbulence in the core and the envelope. We show that as the amplitude of turbulence as well as the scale of turbulent motions decrease from the envelope to the core of the cloud, the diffusion of the magnetic field is faster in the envelope. As a result, the magnetic flux trapped during the collapse in the envelope is being released faster than the flux trapped in the core, resulting in much weaker fields in envelopes than in cores, as observed. We provide simple semi-analytical model calculations which support this conclusion and qualitatively agree with the observational results. Magnetic reconnection is also consistent with the lack of subcritical self-gravitating clouds, with the observed flat PDF of field strengths, and with the scaling of field strength with density. In addition, we demonstrate that the reconnection diffusion process can account for the empirical Larson relations and list a few other implications of the reconnection diffusion concept. We argue that magnetic reconnection provides a solution to the magnetic flux problem of star formation that agrees better with observations than the long-standing ambipolar diffusion paradigm. Due to the illustrative nature of our simplified model we do not seek quantitative agreement, but discuss the complementary nature of our approach to the three-dimensional MHD numerical simulations.

Lazarian, A. [Astronomy Department, University of Wisconsin, Madison, WI 53706 (United States); Esquivel, A. [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-543, 04510 Mexico D.F. (Mexico); Crutcher, R. [Department of Astronomy, University of Illinois at Urbana-Champaign, 1002 W. Green Street, Urbana, IL 61801 (United States)

2012-10-01T23:59:59.000Z

49

Magnetic damping of the translational oscillations of the inner core  

Science Journals Connector (OSTI)

......The associated Lorentz forces and ohmic losses cause...the outer core, inAGU Handbook of Physical Constants...L.B. , 1961. The fundamental free mode of the earth's...The associated Lorentz forces and ohmic losses cause...gravitational restoring forces, although pressure......

Bruce A. Buffett; David E. Goertz

1995-01-01T23:59:59.000Z

50

High-temperature superconducting magnet for use in saturated core FCL  

Science Journals Connector (OSTI)

A HTS magnet system used in a saturated core Fault Current Limiter (FCL) device is described. The superconducting magnet, operating in DC mode, is used in such FCL design for saturating the magnetic core and maintaining low device impedance under nominal conditions. The unique design of the FCL poses constrains on the DC HTS magnet. A model which meets all the necessary special requirements have been realized in a compact magnet design that is optimized for its electrical characteristics while minimizing its mass and volume. The coil, made of Bi-2223 tapes, has 50000 Ampere-turns required to maintain the core in a saturated state at nominal current in the limiting circuit. Unique, nonmagnetic cryostat made of Delrin was used. Cooling of the coil has been realized by two cold heads: one double-stage head that provides a cooling power of 6 W at 20 K and a single-stage head with a cooling capability of 40W at 70 K. This magnetic system has been successfully integrated and tested in a 120 kVA FCL model. The design, characteristics and tests of this magnetic system are described.

Z Bar-Haim; A Friedman; Y Wolfus; V Rozenshtein; F Kopansky; Z Ron; E Harel; N Pundak; Y Yeshurun

2008-01-01T23:59:59.000Z

51

Core magnetic islands and plasma confinement in the H-1NF heliac  

SciTech Connect (OSTI)

Plasma confinement in the vicinity of vacuum magnetic islands near the magnetic axis in the H-1NF heliac [S. M. Hamberger et al., Fusion Technol. 17, 123 (1990)] has been experimentally studied in a low temperature argon plasma. Experimental results indicate that, under favorable conditions, these low order (m=2) islands near the core of the plasma serve as 'pockets' of higher electron density. This results in significant profile modifications including enhancement of the core radial electric field to a large positive value, possibly through an electron-root ambipolar condition. The characteristics of islands are found to be dependent on the plasma collisionality and island width.

Kumar, Santhosh T. A.; Blackwell, Boyd D.; Howard, John; Harris, Jeffrey H. [Plasma Research Laboratory, Research School of Physical Sciences and Engineering, Australian National University, Canberra, ACT 0200 (Australia)

2010-08-15T23:59:59.000Z

52

Fragmentation of Magnetically Subcritical Clouds into Multiple Supercritical Cores and the Formation of Small Stellar Groups  

E-Print Network [OSTI]

Isolated low-mass stars are formed in dense cores of molecular clouds. In the standard picture, the cores are envisioned to condense out of strongly magnetized clouds through ambipolar diffusion. Most previous calculations based on this scenario are limited to axisymmetric cloud evolution leading to a single core, which collapses to form an isolated star or stellar system at the center. These calculations are here extended to the nonaxisymmetric case under thin-disk approximation, which allows for a detailed investigation into the process of fragmentation, fundamental to binary, multiple system, and cluster formation. We have shown previously that initially axisymmetric, magnetically subcritical clouds with an $m=2$ density perturbation of modest fractional amplitude ($\\sim 5%$) can develop highly elongated bars, which facilitate binary and multiple system formation. In this paper, we show that in the presence of higher order ($m\\ge 3$) perturbations of similar amplitude such clouds are capable of breaking up into a set of discrete dense cores. These multiple cores are magnetically supercritical. They are expected to collapse into single stars or stellar systems individually and, collectively, to form a small stellar group. Our calculations demonstrate that the standard scenario for single star formation involving magnetically subcritical clouds and ambipolar diffusion can readily produce more than one star, provided that the cloud mass is well above the Jeans limit and relatively uniformly distributed. The fragments develop in the central part of the cloud, after the region has become magnetically supercritical but before rapid collapse sets in. It is enhanced by the flattening of mass distribution along the field lines and by the magnetic tension force.

Zhi-Yun Li; Fumitaka Nakamura

2002-06-20T23:59:59.000Z

53

Pseudospin magnetism in graphene  

Science Journals Connector (OSTI)

We predict that neutral graphene bilayers are pseudospin magnets in which the charge density contribution from each valley and spin spontaneously shifts to one of the two layers. The band structure of this system is characterized by a momentum-space vortex, which is responsible for unusual competition between band and kinetic energies, leading to symmetry breaking in the vortex core. We discuss the possibility of realizing a pseudospin version of ferromagnetic metal spintronics in graphene bilayers based on hysteresis associated with this broken symmetry.

Hongki Min; Giovanni Borghi; Marco Polini; A. H. MacDonald

2008-01-17T23:59:59.000Z

54

An amorphous alloy core medium frequency magnetic-link for medium voltage photovoltaic inverters  

Science Journals Connector (OSTI)

The advanced magnetic materials with high saturation flux density and low specific core loss have led to the development of an efficient compact and lightweight multiple-input multiple-output medium frequency magnetic-link. It offers a new route to eliminate some critical limitations of recently proposed medium voltage photovoltaic inverters. In this paper a medium frequency magnetic-link is developed with Metglas amorphous alloy 2605S3A. The common magnetic-link generates isolated and balanced multiple DC supplies for all of the H-bridge inverter cells of the medium voltage inverter. The design and implementation of the prototype test platform and the experimental test results are analyzed and discussed. The medium frequency non-sinusoidal excitation electromagnetic characteristics of alloy 2605S3A are also compared with that of alloy 2605SA1. It is expected that the proposed new technology will have great potential for future renewable power generation systems and smart grid applications.

2014-01-01T23:59:59.000Z

55

Magnetization losses in superconducting YBCO conductor-on-round-core (CORC) cables  

Science Journals Connector (OSTI)

Described are the results of magnetization loss measurements made at 77 K on several YBCO conductor-on-round-core (CORC) cables in ac magnetic fields of up to 80 mT in amplitude and frequencies of 50 to 200 Hz, applied perpendicular to the cable axis. The cables contained up to 40 tapes that were wound in as many as 13 layers. Measurements on the cables with different configurations were made as functions of applied ac field amplitude and frequency to determine the effects of their layout on ac loss. In large scale devices such as e.g. Superconducting Magnetic Energy Storage (SMES) magnets, the observed ac losses represent less than 0.1% of their stored energy.

M Majoros; M D Sumption; E W Collings; D C van der Laan

2014-01-01T23:59:59.000Z

56

EXPLORING MAGNETIC FIELD STRUCTURE IN STAR-FORMING CORES WITH POLARIZATION OF THERMAL DUST EMISSION  

SciTech Connect (OSTI)

The configuration and evolution of the magnetic field in star-forming cores are investigated in order to directly compare simulations and observations. We prepare four different initial clouds having different magnetic field strengths and rotation rates, in which magnetic field lines are aligned/misaligned with the rotation axis. First, we calculate the evolution of such clouds from the prestellar stage until long after protostar formation. Then, we calculate the polarization of thermal dust emission expected from the simulation data. We create polarization maps with arbitrary viewing angles and compare them with observations. Using this procedure, we confirmed that the polarization distribution projected on the celestial plane strongly depends on the viewing angle of the cloud. Thus, by comparing the observations with the polarization map predicted by the simulations, we can roughly determine the angle between the direction of the global magnetic field and the line of sight. The configuration of the polarization vectors also depends on the viewing angle. We find that an hourglass configuration of magnetic field lines is not always realized in a collapsing cloud when the global magnetic field is misaligned with the cloud rotation axis. Depending on the viewing angle, an S-shaped configuration of the magnetic field (or the polarization vectors) appears early in the protostellar accretion phase. This indicates that not only the magnetic field but also the cloud rotation affects the dynamical evolution of such a cloud. In addition, by comparing the simulated polarization with actual observations, we can estimate properties of the host cloud such as the evolutionary stage, magnetic field strength, and rotation rate.

Kataoka, Akimasa [Department of Astronomy, Kyoto University, Sakyo-ku, Kyoto 606-8502 (Japan); Machida, Masahiro N. [Department of Earth and Planetary Science, Kyushu University, Higashi-ku, Fukuoka 812-8581 (Japan); Tomisaka, Kohji [Department of Astronomical Science, School of Physical Sciences, Graduate University for Advanced Studies (SOKENDAI), Osawa 2-21-1, Mitaka, Tokyo 181-8588 (Japan)

2012-12-10T23:59:59.000Z

57

SXR-XUV Diagnostics for Edge and Core of Magnetically Confined Plasmas  

SciTech Connect (OSTI)

The present report summarizes the results obtained during a one-year extension of DoE grant “SXR-XUV Diagnostics for Edge and Core of Magnetically Confined Plasmas”, at Johns Hopkins University, aimed at completing the development of a new type of magnetic fusion plasma diagnostic, the XUV Transmission Grating Imaging Radiometer (TGIR). The TGIR enables simultaneous spatially and spectrally resolved measurements of the XUV/VUV radiated power from impurities in fusion plasmas, with high speed. The instrument was successfully developed and qualified in the laboratory and in experiments on a tokamak. Its future applications will be diagnostic of the impurity content and transport in the divertor and edge of advanced magnetic fusion experiments, such as NSTX Upgrade.

Stutman, Dan [Johns Hopkins University

2014-09-10T23:59:59.000Z

58

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

59

Observation of the growth of a magnetic vortex in the transition layer of a mildly relativistic oblique plasma shock  

E-Print Network [OSTI]

A 2D particle simulation models the collision of two electron-ion plasma clouds along a quasi-parallel magnetic field. The collision speed is 0.9c and the density ratio 10. A current sheet forms at the front of the dense cloud, in which the electrons and the magnetic field reach energy equipartition with the ions. A structure composed of a solenoidal and a toroidal magnetic field grows in this sheet. It resembles that in the cross-section of the torus of a force-free spheromak, which may provide the coherent magnetic fields in gamma-ray burst (GRB) jets needed for their prompt emissions.

Murphy, G C; Drury, L O'C

2010-01-01T23:59:59.000Z

60

Direct Imaging of Antiferromagnetic Vortex States  

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

Direct Imaging of Antiferromagnetic Vortex States Print Direct Imaging of Antiferromagnetic Vortex States Print Magnetic materials are characterized by the ordering of electron spins, with nearest-neighbor spins parallel to each other in ferromagnetic (FM) materials and antiparallel to each other in antiferromagnetic (AFM) materials. As the size of a magnetic system is reduced to micron scale, it has been shown that the spins in an FM microstructure can curl around to form a magnetic vortex state. While there has been intensive activity in the study of vortex states in FM disks, there has been no direct observation of such states in an AFM microstructure, although theory predicts many interesting and unique properties for the AFM vortex state. Recently, a research team from Berkeley, Korea, and China has taken the first direct image of an AFM vortex in multilayered magnetic disk structures using x-ray magnetic linear dichroism (XMLD) and photoemission electron microscopy (PEEM) at ALS Beamlines 4.0.2 and 11.0.1 , respectively. The experiments observed two types of AFM vortices, one of which has no analogue in FM vortices.

Note: This page contains sample records for the topic "magnetic vortex core" 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

Direct Imaging of Antiferromagnetic Vortex States  

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

Direct Imaging of Antiferromagnetic Vortex States Print Direct Imaging of Antiferromagnetic Vortex States Print Magnetic materials are characterized by the ordering of electron spins, with nearest-neighbor spins parallel to each other in ferromagnetic (FM) materials and antiparallel to each other in antiferromagnetic (AFM) materials. As the size of a magnetic system is reduced to micron scale, it has been shown that the spins in an FM microstructure can curl around to form a magnetic vortex state. While there has been intensive activity in the study of vortex states in FM disks, there has been no direct observation of such states in an AFM microstructure, although theory predicts many interesting and unique properties for the AFM vortex state. Recently, a research team from Berkeley, Korea, and China has taken the first direct image of an AFM vortex in multilayered magnetic disk structures using x-ray magnetic linear dichroism (XMLD) and photoemission electron microscopy (PEEM) at ALS Beamlines 4.0.2 and 11.0.1 , respectively. The experiments observed two types of AFM vortices, one of which has no analogue in FM vortices.

62

Direct Imaging of Antiferromagnetic Vortex States  

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

Direct Imaging of Antiferromagnetic Vortex States Print Direct Imaging of Antiferromagnetic Vortex States Print Magnetic materials are characterized by the ordering of electron spins, with nearest-neighbor spins parallel to each other in ferromagnetic (FM) materials and antiparallel to each other in antiferromagnetic (AFM) materials. As the size of a magnetic system is reduced to micron scale, it has been shown that the spins in an FM microstructure can curl around to form a magnetic vortex state. While there has been intensive activity in the study of vortex states in FM disks, there has been no direct observation of such states in an AFM microstructure, although theory predicts many interesting and unique properties for the AFM vortex state. Recently, a research team from Berkeley, Korea, and China has taken the first direct image of an AFM vortex in multilayered magnetic disk structures using x-ray magnetic linear dichroism (XMLD) and photoemission electron microscopy (PEEM) at ALS Beamlines 4.0.2 and 11.0.1 , respectively. The experiments observed two types of AFM vortices, one of which has no analogue in FM vortices.

63

THE ANGULAR MOMENTUM OF MAGNETIZED MOLECULAR CLOUD CORES: A TWO-DIMENSIONAL-THREE-DIMENSIONAL COMPARISON  

SciTech Connect (OSTI)

In this work, we present a detailed study of the rotational properties of magnetized and self-gravitating dense molecular cloud (MC) cores formed in a set of two very high resolution three-dimensional (3D) MC simulations with decaying turbulence. The simulations have been performed using the adaptative mesh refinement code RAMSES with an effective resolution of 4096{sup 3} grid cells. One simulation represents a mildly magnetically supercritical cloud and the other a strongly magnetically supercritical cloud. We identify dense cores at a number of selected epochs in the simulations at two density thresholds which roughly mimic the excitation densities of the NH{sub 3} (J - K) = (1,1) transition and the N{sub 2}H{sup +} (1-0) emission line. A noticeable global difference between the two simulations is the core formation efficiency (CFE) of the high-density cores. In the strongly supercritical simulations, the CFE is 33% per unit free-fall time of the cloud (t{sub ff,cl}), whereas in the mildly supercritical simulations this value goes down to {approx}6 per unit t{sub ff,cl}. A comparison of the intrinsic specific angular momentum (j{sub 3D}) distributions of the cores with the specific angular momentum derived using synthetic two-dimensional (2D) velocity maps of the cores (j{sub 2D}) shows that the synthetic observations tend to overestimate the true value of the specific angular momentum by a factor of {approx}8-10. We find that the distribution of the ratio j{sub 3D}/j{sub 2D} of the cores peaks at around {approx}0.1. The origin of this discrepancy lies in the fact that contrary to the intrinsic determination of j which sums up the individual gas parcels' contributions to the angular momentum, the determination of the specific angular momentum using the standard observational procedure which is based on a measurement on the global velocity gradient under the hypothesis of uniform rotation smoothes out the complex fluctuations present in the 3D velocity field. Our results may well provide a natural explanation for the discrepancy by a factor of {approx}10 observed between the intrinsic 3D distributions of the specific angular momentum and the corresponding distributions derived in real observations. We suggest that previous and future measurements of the specific angular momentum of dense cores which are based on the measurement of the observed global velocity gradients may need to be reduced by a factor of {approx}10 in order to derive a more accurate estimate of the true specific angular momentum in the cores. We also show that the exponent of the size-specific angular momentum relation is smaller ({approx}1.4) in the synthetic observations than their values derived in the 3D space ({approx}1.8).

Dib, Sami; Csengeri, Timea; Audit, Edouard [Service d'Astrophysique, DSM/Irfu, CEA/Saclay, F-91191, Gif-sur-Yvette Cedex (France); Hennebelle, Patrick [Laboratoire de Radioastronomie, UMR CNRS 8112, Ecole Normale Superieure, Observatoire de Paris, 24 rue Lhomond, 75231 Paris Cedex 05 (France); Pineda, Jaime E.; Goodman, Alyssa A. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Bontemps, Sylvain, E-mail: sami.dib@cea.f [CNRS/INU, Laboratoire d'Astrophysique de Bordeaux, UMR 5804, BP 89, 33271, Floirac, Cedex (France)

2010-11-01T23:59:59.000Z

64

Induced Core Formation Time in Subcritical Magnetic Clouds by Large-Scale Trans-Alfv\\'enic Flows  

E-Print Network [OSTI]

We clarify the mechanism of accelerated core formation by large-scale nonlinear flows in subcritical magnetic clouds by finding a semi-analytical formula for the core formation time and describing the physical processes that lead to them. Recent numerical simulations show that nonlinear flows induce rapid ambipolar diffusion that leads to localized supercritical regions that can collapse. Here, we employ non-ideal magnetohydrodynamic simulations including ambipolar diffusion for gravitationally stratified sheets threaded by vertical magnetic fields. One of the horizontal dimensions is eliminated, resulting in a simpler two-dimensional simulation that can clarify the basic process of accelerated core formation. A parameter study of simulations shows that the core formation time is inversely proportional to the square of the flow speed when the flow speed is greater than the Alfv\\'en speed. We find a semi-analytical formula that explains this numerical result. The formula also predicts that the core formation t...

Kudoh, Takahiro

2014-01-01T23:59:59.000Z

65

Lower pseudogap phase of Mott insulators: A spin/vortex liquid state  

Science Journals Connector (OSTI)

The pseudogap phase is considered to be a new state of matter in the phase string model of the doped Mott insulator, which is composed of two distinct regimes known as the upper and lower pseudogap phases, respectively. The former corresponds to the formation of spin-singlet pairing, the magnetic characterizations of which have been recently studied [Phys. Rev. B 72, 104520 (2005)]. The latter, as a low-temperature regime of the pseudogap phase, is systematically explored in this work, which is characterized by the formation of the Cooper pair amplitude and described by a generalized Ginzburg-Landau theory. Elementary excitation in this phase is a charge-neutral object carrying spin-1?2 and locking with a supercurrent vortex, known as a spinon-vortex composite. Such a lower pseudogap phase can be regarded as a vortex liquid state due to the presence of free spinon vortices. Here thermally excited spinon vortices destroy the phase coherence and are responsible for the nontrivial Nernst effect and diamagnetism. The transport entropy and core energy associated with a spinon vortex are determined by the spin degrees of freedom. Such a spontaneous vortex liquid phase can be also considered as a spin liquid with a finite correlation length and gaped S=1?2 excitations, where a resonancelike nonpropagating spin mode emerges at the antiferromagnetic wavevector (?,?) with a doping-dependent characteristic energy. The superconducting phase is closely related to the lower pseudogap phase by a topological transition with spinon vortices and antivortices forming bound pairs and the emergence of fermionic quasiparticles as holon-spinon-vortex bound objects. A quantitative phase diagram in the parameter space of doping, temperature, and magnetic field is determined. Comparisons with experiments are also made.

Zheng-Yu Weng and Xiao-Liang Qi

2006-10-26T23:59:59.000Z

66

Vortex configurations of bosons in an optical lattice  

SciTech Connect (OSTI)

The single-vortex problem in a strongly correlated bosonic system is investigated self-consistently within the mean-field theory of the Bose-Hubbard model. Near the superfluid-Mott-insulator transition, the vortex core has a tendency toward the Mott-insulating phase, with the core particle density approaching the nearest commensurate value. If the nearest-neighbor repulsion exists, the charge-density wave order may develop locally in the core. The evolution of the vortex configuration from the strong- to weak-coupling regions is studied. This phenomenon can be observed in systems of rotating ultracold atoms in optical lattices and Josephson-junction arrays.

Wu Congjun; Zhang Shoucheng [Department of Physics, McCullough Building, Stanford University, Stanford, California 94305-4045 (United States); Chen Handong [Department of Applied Physics, McCullough Building, Stanford University, Stanford, California 94305-4045 (United States); Hu Jiangpiang [Department of Physics and Astronomy, University of California, Los Angeles, California 90095-1547 (United States)

2004-04-01T23:59:59.000Z

67

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

E-Print Network [OSTI]

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

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

2009-11-15T23:59:59.000Z

68

Coaxial-Electrospun Magnetic Core–Shell Fe@TiSi Nanofibers for the Rapid Purification of Typical Dye Wastewater  

Science Journals Connector (OSTI)

It is very important that the magnetic nanofibers could be recycled rapidly with an outside magnet, and the actual water treatment process was easy to achieve. ... However, additional ?-Fe2O3 core can make fibrous catalysts be more easily recycled from water using outside magnets. ... Yavuz, C. T.; Mayo, J. T.; Yu, W. W.; Prakash, A.; Falkner, J. C.; Yean, S.; Cong, L. L.; Shipley, H. J.; Kan, A.; Tomson, M.; Natelson, D.; Colvin, V. L.Low-Field Magnetic Separation of Monodisperse Fe3O4 Nanocrystals Science 2006, 314, 964– 967 ...

Sihui Zhan; Dandan Zhu; Guangyuan Ren; Zhiqiang Shen; Mingying Qiu; Shanshan Yang; Hongbing Yu; Yi Li

2014-09-16T23:59:59.000Z

69

Vortex lines in films: Fields and interactions  

Science Journals Connector (OSTI)

General expressions are given for the magnetic field and energy of arbitrary arrangements of straight and curved vortices in an anisotropic superconductor film of finite thickness within anisotropic London theory. As examples we consider the magnetic field and interaction of straight perpendicular vortex lines in films of finite thickness.

Gilson Carneiro and Ernst Helmut Brandt

2000-03-01T23:59:59.000Z

70

Temperature dependence of vortex charges in high-temperature superconductors  

Science Journals Connector (OSTI)

Using a model Hamiltonian with d-wave superconductivity and competing antiferromagnetic (AF) interactions, the temperature (T) dependence of the vortex charge in high-Tc superconductors is investigated by numerically solving the Bogoliubov–de Gennes equations. The strength of the induced AF order inside the vortex core is T dependent. The vortex charge could be negative when the AF order with sufficient strength is present at low temperatures. At higher temperatures, the AF order may be completely suppressed and the vortex charge becomes positive. A first-order-like transition in the T-dependent vortex charge is seen near the critical temperature TAF. For an underdoped sample, the spatial profiles of the induced spin-density wave and the charge-density wave orders could have stripelike structures at TTs. As a result, a vortex charge discontinuity occurs at Ts.

Yan Chen; Z. D. Wang; C. S. Ting

2003-06-03T23:59:59.000Z

71

Vortex reconnections in atomic condensates at finite temperature A. J. Allen1  

E-Print Network [OSTI]

, reconnections of stream lines, vortex lines and magnetic flux tubes change the topology of the flowVortex reconnections in atomic condensates at finite temperature A. J. Allen1 , S. Zuccher2 , M (Dated: May 28, 2014) The study of vortex reconnections is an essential ingredient of understanding

Zuccher, Simone

72

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

73

Diffusive magnetic images of upwelling patterns in the core Peter Olson, Ikuro Sumita,1  

E-Print Network [OSTI]

the magnetic field, including stretching of the field lines by the fluid and magnetic diffusion. [3] Since field electrodynamics. The method assumes a frozen magnetic flux balance for the global-scale part of the fluid velocity. The diffusive flux balance implies that local highs and lows in the magnetic field

74

Vortex Dynamics in NanoScale Materials  

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

Into the Vortex: Dynamics in Nanoscale Materials Into the Vortex: Dynamics in Nanoscale Materials Micron and nanosized magnets are of great interest for their potential applications in new electronic devices, such as magnetic random access memories. As the size of magnets is reduced to a 1-micron scale and below, the boundaries (surfaces, perimeters, etc) of the objects begin to profoundly influence both the static and dynamic behavior of the materials. Researchers from Argonne's Materials Science Division (MSD), Center for Nanoscale Materials (CNM), and Advanced Photon Source (APS) have recently examined the dynamics of 3- to 7-micron-diameter NiFe alloy disks with a combination of theoretical calculations and a new time-resolved magnetic imaging technique using synchrotron-based x-ray photoemission electron

75

Improved vortex reactor system  

DOE Patents [OSTI]

An improved vortex reactor system for affecting fast pyrolysis of biomass and Refuse Derived Fuel (RDF) feed materials comprising: a vortex reactor having its axis vertically disposed in relation to a jet of a horizontally disposed steam ejector that impels feed materials from a feeder and solids from a recycle loop along with a motive gas into a top part of said reactor.

Diebold, James P. (Lakewood, CO); Scahill, John W. (Evergreen, CO)

1995-01-01T23:59:59.000Z

76

Creation and pinning of vortex-antivortex pairs  

E-Print Network [OSTI]

Computer modeling is reported about the creation and pinning of a magnetic vortex-antivortex (V-AV) pair in a superconducting thin film, due to the magnetic field of a vertical magnetic dipole above the film, and two antidot pins inside the film...

Kim, Sangbum; Hu, Chia-Ren; Andrews, Malcolm J.

2006-01-01T23:59:59.000Z

77

Magnetic Inhibition of Convection and the Fundamental Properties of Low-Mass Stars. I. Stars with a Radiative Core  

E-Print Network [OSTI]

Magnetic fields are hypothesized to inflate the radii of low-mass stars---defined as less massive than 0.8 solar masses---in detached eclipsing binaries (DEBs). We investigate this hypothesis using the recently introduced magnetic Dartmouth stellar evolution code. In particular, we focus on stars thought to have a radiative core and convective outer envelope by studying in detail three individual DEBs: UV Psc, YY Gem, and CU Cnc. The results suggest that the stabilization of thermal convection by a magnetic field is a plausible explanation for the observed model-radius discrepancies. However, surface magnetic field strengths required by the models are significantly stronger than those estimated from the observed coronal X-ray emission. Agreement between model predicted surface magnetic field strengths and those inferred from X-ray observations can be found by assuming that the magnetic field sources its energy from convection. This approach makes the transport of heat by convection less efficient and is akin ...

Feiden, Gregory A

2013-01-01T23:59:59.000Z

78

Neutron Scattering Studies of Vortex Matter in Type-II Superconductors  

SciTech Connect (OSTI)

The proposed program is an experimental study of the fundamental properties of Abrikosov vortex matter in type-II superconductors. Most superconducting materials used in applications such as MRI are type II and their transport properties are determined by the interplay between random pinning, interaction and thermal fluctuation effects in the vortex state. Given the technological importance of these materials, a fundamental understanding of the vortex matter is necessary. The vortex lines in type-II superconductors also form a useful model system for fundamental studies of a number of important issues in condensed matter physics, such as the presence of a symmetry-breaking phase transition in the presence of random pinning. Recent advances in neutron scattering facilities such as the major upgrade of the NIST cold source and the Spallation Neutron Source are providing unprecedented opportunities in addressing some of the longstanding issues in vortex physics. The core component of the proposed program is to use small angle neutron scattering and Bitter decoration experiments to provide the most stringent test of the Bragg glass theory by measuring the structure factor in both the real and reciprocal spaces. The proposed experiments include a neutron reflectometry experiment to measure the precise Q-dependence of the structure factor of the vortex lattice in the Bragg glass state. A second set of SANS experiments will be on a shear-strained Nb single crystal for testing a recently proposed theory of the stability of Bragg glass. The objective is to artificially create a set of parallel grain boundaries into a Nb single crystal and use SANS to measure the vortex matter diffraction pattern as a function of the changing angle between the applied magnetic field to the grain boundaries. The intrinsic merits of the proposed work are a new fundamental understanding of type-II superconductors on which superconducting technology is based, and a firm understanding of phases and phase transitions in condensed matter systems with random pinning. The broader impact of the program includes the training of future generation of neutron scientists, and further development of neutron scattering and complementary techniques for studies of superconducting materials. The graduate and undergraduate students participating in this project will learn the state-of-the-art neutron scattering techniques, acquire a wide range of materials research experiences, and participate in the frontier research of superconductivity. This should best prepare the students for future careers in academia, industry, or government.

Xinsheng Ling

2012-02-02T23:59:59.000Z

79

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

80

Nanoscale strain-induced pair suppression as a vortex-pinning mechanism in high- temperature superconductors  

SciTech Connect (OSTI)

Boosting large-scale superconductor applications require nanostructured conductors with artificial pinning centres immobilizing quantized vortices at high temperature and magnetic fields. Here we demonstrate a highly effective mechanism of artificial pinning centers in solution-derived high-temperature superconductor nanocomposites through generation of nanostrained regions where Cooper pair formation is suppressed. The nanostrained regions identified from transmission electron microscopy devise a very high concentration of partial dislocations associated with intergrowths generated between the randomly oriented nanodots and the epitaxial YBa{sub 2}Cu{sub 3}O{sub 7} matrix. Consequently, an outstanding vortex-pinning enhancement correlated to the nanostrain is demonstrated for four types of randomly oriented nanodot, and a unique evolution towards an isotropic vortex-pinning behaviour, even in the effective anisotropy, is achieved as the nanostrain turns isotropic. We suggest a new vortex-pinning mechanism based on the bond-contraction pairing model, where pair formation is quenched under tensile strain, forming new and effective core-pinning regions.

Llordes, Anna [ICMAB, Barcelona, Spain; Palau, A. [ICMAB, Barcelona, Spain; Gazquez, J. [Oak Ridge National Laboratory (ORNL); Coll, M. [ICMAB, Barcelona, Spain; Vlad, R. [ICMAB, Barcelona, Spain; Pomar, A. [ICMAB, Barcelona, Spain; Arbiol, Jordi [ICMAB, Barcelona, Spain; Guzman, Roger [ICMAB, Barcelona, Spain; Ye, S. [ICMAB, Barcelona, Spain; Rouco, V [ICMAB, Barcelona, Spain; Sandiumenge, Felip [ICMAB, Barcelona, Spain; Ricart, Susagna [ICMAB, Barcelona, Spain; Puig, Teresa [ICMAB, Barcelona, Spain; Varela del Arco, Maria [ORNL; Chataigner, D. [CRISMAT, Caen, France; Vanacken, J. [INPAC-Institute for Nanoscale Physics and Chemistry, Leuven, Belgium; Gutierrez, J. [INPAC-Institute for Nanoscale Physics and Chemistry, Leuven, Belgium; Moschalkov, V. [INPAC-Institute for Nanoscale Physics and Chemistry, Leuven, Belgium; Deutscher, G. [Tel Aviv University; Magen Dominguez, Cesar [ORNL; Obradors, Xavier [ICMAB, Barcelona, Spain

2012-01-01T23:59:59.000Z

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81

Field dependence of the vortex structure in d-wave and s-wave superconductors  

Science Journals Connector (OSTI)

We study the vortex structure and its field dependence within the framework of the quasiclassical Eilenberger theory to find the difference between the dx2-y2- and s-wave pairings. We clarify the effect of the dx2-y2-wave nature and the vortex lattice effect on the vortex structure of the pair potential, the internal field and the local density of states. The dx2-y2-wave pairing introduces a fourfold-symmetric structure around each vortex core. With increasing field, their contribution becomes significant to the whole structure of the vortex lattice state, depending on the vortex lattice’s configuration. It is reflected in the form factor of the internal field, which may be detected by small-angle neutron scattering, or the resonance line shape of muon spin resonance and NMR experiments. We also study the induced s- and dxy-wave components around the vortex in dx2-y2-wave superconductors.

Masanori Ichioka; Akiko Hasegawa; Kazushige Machida

1999-04-01T23:59:59.000Z

82

Self-Consistent Electronic Structure of a dx2-y2 and a dx2-y2 + idxy Vortex  

Science Journals Connector (OSTI)

We investigate quasiparticle states associated with an isolated vortex in a d-wave superconductor using a self-consistent Bogoliubov–de Gennes formalism. For a pure dx2-y2 superconductor we find that there exist no bound states in the core; all the states are extended with continuous energy spectrum. This result is inconsistent with the existing experimental data on cuprates. We propose an explanation for this data in terms of a magnetic-field-induced dx2-y2+idxy state recently invoked in connection with the thermal conductivity measurements on Bi2Sr2CaCu2O8.

M. Franz and Z. Tešanovi?

1998-05-25T23:59:59.000Z

83

Improved vortex reactor system  

DOE Patents [OSTI]

An improved vortex reactor system is described for affecting fast pyrolysis of biomass and Refuse Derived Fuel (RDF) feed materials comprising: a vortex reactor having its axis vertically disposed in relation to a jet of a horizontally disposed steam ejector that impels feed materials from a feeder and solids from a recycle loop along with a motive gas into a top part of said reactor. 12 figs.

Diebold, J.P.; Scahill, J.W.

1995-05-09T23:59:59.000Z

84

Magnetization-induced enhancement of photoluminescence in core-shell CoFe{sub 2}O{sub 4}@YVO{sub 4}:Eu{sup 3+} composite  

SciTech Connect (OSTI)

After the core-shell CoFe{sub 2}O{sub 4}@YVO{sub 4}:Eu{sup 3+} composite synthesized through a facile sol-gel method was magnetized under an external magnetic field of 0.25?T for 4?h, an enhancement of ?56% in photoluminescence intensity was observed. The remanent magnetization of the CoFe{sub 2}O{sub 4} core increases the intensity of the excited charge transfer transition of VO{sub 4}{sup 3?} group in YVO{sub 4}:Eu{sup 3+} shell, which may enhance the probability related to the Eu{sup 3+} radiative transition {sup 5}D{sub 0}-{sup 7}F{sub 2}, yielding to a high photoluminescence. The obvious remanent-magnetization-induced enhancement in photoluminescence is helpful in developing excellent magnetic/luminescent material for the practical display devices.

Jia, Yanmin, E-mail: ymjia@zjnu.edu.cn, E-mail: wuzheng@zjnu.cn; Zhou, Zhihua; Wei, Yongbin [Department of Physics, Zhejiang Normal University, Jinhua 321004 (China); Wu, Zheng, E-mail: ymjia@zjnu.edu.cn, E-mail: wuzheng@zjnu.cn; Chen, Jianrong [College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua 321004 (China); Zhang, Yihe [School of Materials Science and Technology, China University of Geosciences, Beijing 100083 (China); Liu, Yongsheng [Department of Physics, Shanghai University of Electric Power, Shanghai 200090 (China)

2013-12-07T23:59:59.000Z

85

The development of magnetic resonance imaging for the determination of porosity in reservoir core samples  

E-Print Network [OSTI]

to increase. This is the resonance condition and is the principle upon which magnetic resonance imaging is founded. The resonance frequency, tu, is directly proportional to the magnetic field and can be expressed as: where y is the gyromagnetic ratio and H... system is also precessing about y' with the same rotational frequency as M. This is the rotating frame of reference. By convention, z' is set equal to z and, therefore, H . As long as H remains at a constant strength and is the only field applied...

Sherman, Byron Blake

2012-06-07T23:59:59.000Z

86

Vortex Characterization for Engineering Applications  

SciTech Connect (OSTI)

Realistic engineering simulation data often have features that are not optimally resolved due to practical limitations on mesh resolution. To be useful to application engineers, vortex characterization techniques must be sufficiently robust to handle realistic data with complex vortex topologies. In this paper, we present enhancements to the vortex topology identification component of an existing vortex characterization algorithm. The modified techniques are demonstrated by application to three realistic data sets that illustrate the strengths and weaknesses of our approach.

Jankun-Kelly, M; Thompson, D S; Jiang, M; Shannahan, B; Machiraju, R

2008-01-30T23:59:59.000Z

87

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....

88

Nucleation-controlled vortex entry in a square-columnar Josephson-junction array  

SciTech Connect (OSTI)

The initial magnetization curve of square-columnar Josephson-junction arrays is calculated from fundamental laws. It is found that the first vortex entry is controlled by vortex nucleation rather than surface depinning and it occurs at a field greater than that predicted by the traditional surface-barrier theory. {copyright} {ital 1997} {ital The American Physical Society}

Chen, D.; Moreno, J.J.; Hernando, A. [Instituto de Magnetismo Aplicado, RENFE-UCM-CSIC, 28230 Las Rozas, Madrid (Spain)] [Instituto de Magnetismo Aplicado, RENFE-UCM-CSIC, 28230 Las Rozas, Madrid (Spain)

1997-08-01T23:59:59.000Z

89

Nanoscale strain-induced pair suppression as a source of vortex pinning in high-temperature superconductors  

SciTech Connect (OSTI)

Boosting large-scale superconductor applications require nanostructured conductors with artificial pinning centres immobilizing quantized vortices at high temperature and magnetic fields. Here we demonstrate a highly effective mechanism of artificial pinning centres in solution-derived high-temperature superconductor nanocomposites through generation of nanostrained regions where Cooper pair formation is suppressed. The nanostrained regions identified from transmission electron microscopy devise a very high concentration of partial dislocations associated with intergrowths generated between the randomly oriented nanodots and the epitaxial YBa{sub 2}Cu{sub 3}O{sub 7} matrix. Consequently, an outstanding vortex-pinning enhancement correlated to the nanostrain is demonstrated for four types of randomly oriented nanodot, and a unique evolution towards an isotropic vortex-pinning behaviour, even in the effective anisotropy, is achieved as the nanostrain turns isotropic. We suggest a new vortex-pinning mechanism based on the bond-contraction pairing model, where pair formation is quenched under tensile strain, forming new and effective core-pinning regions.

Llordes, A. [ICMAB, Barcelona, Spain; Palau, A. [ICMAB, Barcelona, Spain; Vlad, R. [ICMAB, Barcelona, Spain; Pomar, A. [ICMAB, Barcelona, Spain; Arbiol, Jordi [ICMAB, Barcelona, Spain; Guzman, Roger [ICMAB, Barcelona, Spain; Gazquez Alabart, Jaume [ORNL; Varela del Arco, Maria [ORNL; Sandiumenge, Felip [ICMAB, Barcelona, Spain; Ricart, Susagna [ICMAB, Barcelona, Spain; Puig, Teresa [ICMAB, Barcelona, Spain; Chataigner, D. [CRISMAT, Caen, France; Vanacken, J. [INPAC-Institute for Nanoscale Physics and Chemistry, Leuven, Belgium; Gutierrez, J. [INPAC-Institute for Nanoscale Physics and Chemistry, Leuven, Belgium; Deutscher, G. [Tel Aviv University; Moschalkov, V. [INPAC-Institute for Nanoscale Physics and Chemistry, Leuven, Belgium; Obradors, Xavier [ICMAB, Barcelona, Spain

2012-01-01T23:59:59.000Z

90

Vortex motion in Josephson-junction arrays near f=0 and f=1/2  

Science Journals Connector (OSTI)

We study vortex motion in two-dimensional Josephson arrays at magnetic fields near zero and one-half flux quanta per plaquette (f=0 and f=1/2). The array is modeled as a network of resistively and capacitively shunted Josephson junctions at temperature T=0. Calculations are carried out over a range of the McCumber-Stewart junction damping parameter ?. Near both f=0 and f=1/2, the I-V characteristics exhibit two critical currents, Ic1(f) and Ic2(f), representing the critical current for depinning a single vortex, and for depinning the entire ground-state phase configuration. Near f=0, single vortex motion just above Ic1(0) leads to Josephson-like voltage oscillations. The motion of the vortex is seemingly overdamped (i.e., nonhysteretic) even when the individual junction parameters are highly underdamped, in agreement with experiments. At sufficiently large ?, and sufficiently high vortex velocity, the vortex breaks up into a row of resistively switched junctions perpendicular to the current. Near f=1/2, the vortex potential, and corresponding vortex trajectories, are more complicated than near f=0. Nevertheless, the vortex is still ‘‘overdamped’’ even when the individual junctions are highly underdamped, and there is still row-switching behavior at large values of ?. A high-energy vortex in a very underdamped array tends to generate resistively switched rows rather than to move ballistically. Some possible explanations for this behavior are discussed.

Wenbin Yu; K. H. Lee; D. Stroud

1993-03-01T23:59:59.000Z

91

Low-field vortex matter in YBa2Cu3O7 : An atomic beam magnetic-resonance study Harald Hauglin  

E-Print Network [OSTI]

the rate that rf magnetic-resonance hyperfine tran- sitions are excited in atoms as they pass over Department of Physics, University of Oslo, N-0316 Oslo, Norway Nathan G. Woodard, Samuel Dapore-Schwartz, and Gregory P. Lafyatis Department of Physics, The Ohio State University, Columbus, Ohio 43210-1106 Received

Johansen, Tom Henning

92

Liquid Vortex Shielding for Fusion Energy Applications  

SciTech Connect (OSTI)

Swirling liquid vortices can be used in fusion chambers to protect their first walls and critical elements from the harmful conditions resulting from fusion reactions. The beam tube structures in heavy ion fusion (HIF) must be shielded from high energy particles, such as neutrons, x-rays and vaporized coolant, that will cause damage. Here an annular wall jet, or vortex tube, is proposed for shielding and is generated by injecting liquid tangent to the inner surface of the tube both azimuthally and axially. Its effectiveness is closely related to the vortex tube flow properties. 3-D particle image velocimetry (PIV) is being conducted to precisely characterize its turbulent structure. The concept of annular vortex flow can be extended to a larger scale to serve as a liquid blanket for other inertial fusion and even magnetic fusion systems. For this purpose a periodic arrangement of injection and suction holes around the chamber circumference are used, generating the layer. Because it is important to match the index of refraction of the fluid with the tube material for optical measurement like PIV, a low viscosity mineral oil was identified and used that can also be employed to do scaled experiments of molten salts at high temperature.

Bardet, Philippe M. [University of California, Berkeley (United States); Supiot, Boris F. [University of California, Berkeley (United States); Peterson, Per F. [University of California, Berkeley (United States); Savas, Oemer [University of California, Berkeley (United States)

2005-05-15T23:59:59.000Z

93

Electromagnetic Behavior of the Vortex Sponge  

Science Journals Connector (OSTI)

In an introductory paper the vortex sponge was shown to be governed in restricted cases by Maxwell's free-space equations. In the present paper analogs to electric and magnetic energies and Poynting's theorem are derived by simple mechanical considerations. Rotational stability suggested originally by MacCullagh as a fundamental property of a luminiferous ether turns out to be a quality of the medium as do the stresses introduced by Faraday and Maxwell to explain the mechanical actions of electric and magnetic fields. A rudimentary model for the electrostatic field is suggested on this basis. A conventional definition of charge and the laws of Coulomb and Biot complete Maxwell's equations for cases including charges and currents. A model of the magnetic field based on the bulk rotation and the Faraday-Maxwell stresses combined with the laws of Coulomb and Biot permits the inference of the Lorentz force. Although numerous gaps occur in the treatment it seems not unlikely that the vortex sponge has the qualities described by the electromagnetic field equations as well as the mechanical attributes required for a model of these fields.

Edward M. Kelly

1964-01-01T23:59:59.000Z

94

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

95

Influence of Domain Wall Pinning on the Dynamic Behavior of Magnetic  

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

Influence of Domain Wall Pinning on the Dynamic Behavior of Magnetic Vortices Print Influence of Domain Wall Pinning on the Dynamic Behavior of Magnetic Vortices Print Soft magnetic, micron-sized thin-film structures with magnetic vortices are intriguing systems that may one day be used in ultrafast computer memories. In such systems, the otherwise in-plane magnetization turns perpendicular to the plane at the center of the vortex, forming the vortex core. Because such a core has two possible polarizations (up or down) and can be switched between these two states by a small alternating magnetic field, it could serve as a memory bit in future magnetic memory devices. However, these magnetic structures often contain numerous imperfections such as domain wall pinning sites, which have to be taken into account for the practical application of such systems. To study how these defects affect the dynamics of magnetic vortices, researchers from Belgium, Germany, and the United States investigated square-shaped and disk-shaped thin-film structures with artificially introduced imperfections in the form of nanometer-sized holes. They used time-resolved scanning transmission x-ray microscopy (STXM) at ALS Beamline 11.0.2 to determine the frequency at which these vortices vibrate (their eigenfrequency). The imperfections were found to cause a higher vibrational frequency in square-shaped structures, but did not influence the disk-shaped structures. Knowledge of the frequency is crucial for vortex-based memories, since the electric signal for writing data needs to be precisely tuned to it.

96

Influence of Domain Wall Pinning on the Dynamic Behavior of Magnetic  

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

Influence of Domain Wall Pinning on the Dynamic Behavior of Magnetic Vortices Print Influence of Domain Wall Pinning on the Dynamic Behavior of Magnetic Vortices Print Soft magnetic, micron-sized thin-film structures with magnetic vortices are intriguing systems that may one day be used in ultrafast computer memories. In such systems, the otherwise in-plane magnetization turns perpendicular to the plane at the center of the vortex, forming the vortex core. Because such a core has two possible polarizations (up or down) and can be switched between these two states by a small alternating magnetic field, it could serve as a memory bit in future magnetic memory devices. However, these magnetic structures often contain numerous imperfections such as domain wall pinning sites, which have to be taken into account for the practical application of such systems. To study how these defects affect the dynamics of magnetic vortices, researchers from Belgium, Germany, and the United States investigated square-shaped and disk-shaped thin-film structures with artificially introduced imperfections in the form of nanometer-sized holes. They used time-resolved scanning transmission x-ray microscopy (STXM) at ALS Beamline 11.0.2 to determine the frequency at which these vortices vibrate (their eigenfrequency). The imperfections were found to cause a higher vibrational frequency in square-shaped structures, but did not influence the disk-shaped structures. Knowledge of the frequency is crucial for vortex-based memories, since the electric signal for writing data needs to be precisely tuned to it.

97

Influence of Domain Wall Pinning on the Dynamic Behavior of Magnetic  

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

Influence of Domain Wall Pinning on the Dynamic Behavior of Magnetic Vortices Print Influence of Domain Wall Pinning on the Dynamic Behavior of Magnetic Vortices Print Soft magnetic, micron-sized thin-film structures with magnetic vortices are intriguing systems that may one day be used in ultrafast computer memories. In such systems, the otherwise in-plane magnetization turns perpendicular to the plane at the center of the vortex, forming the vortex core. Because such a core has two possible polarizations (up or down) and can be switched between these two states by a small alternating magnetic field, it could serve as a memory bit in future magnetic memory devices. However, these magnetic structures often contain numerous imperfections such as domain wall pinning sites, which have to be taken into account for the practical application of such systems. To study how these defects affect the dynamics of magnetic vortices, researchers from Belgium, Germany, and the United States investigated square-shaped and disk-shaped thin-film structures with artificially introduced imperfections in the form of nanometer-sized holes. They used time-resolved scanning transmission x-ray microscopy (STXM) at ALS Beamline 11.0.2 to determine the frequency at which these vortices vibrate (their eigenfrequency). The imperfections were found to cause a higher vibrational frequency in square-shaped structures, but did not influence the disk-shaped structures. Knowledge of the frequency is crucial for vortex-based memories, since the electric signal for writing data needs to be precisely tuned to it.

98

Influence of Domain Wall Pinning on the Dynamic Behavior of Magnetic  

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

Influence of Domain Wall Pinning on the Dynamic Behavior of Magnetic Vortices Print Influence of Domain Wall Pinning on the Dynamic Behavior of Magnetic Vortices Print Soft magnetic, micron-sized thin-film structures with magnetic vortices are intriguing systems that may one day be used in ultrafast computer memories. In such systems, the otherwise in-plane magnetization turns perpendicular to the plane at the center of the vortex, forming the vortex core. Because such a core has two possible polarizations (up or down) and can be switched between these two states by a small alternating magnetic field, it could serve as a memory bit in future magnetic memory devices. However, these magnetic structures often contain numerous imperfections such as domain wall pinning sites, which have to be taken into account for the practical application of such systems. To study how these defects affect the dynamics of magnetic vortices, researchers from Belgium, Germany, and the United States investigated square-shaped and disk-shaped thin-film structures with artificially introduced imperfections in the form of nanometer-sized holes. They used time-resolved scanning transmission x-ray microscopy (STXM) at ALS Beamline 11.0.2 to determine the frequency at which these vortices vibrate (their eigenfrequency). The imperfections were found to cause a higher vibrational frequency in square-shaped structures, but did not influence the disk-shaped structures. Knowledge of the frequency is crucial for vortex-based memories, since the electric signal for writing data needs to be precisely tuned to it.

99

Magnetic core mounting system  

DOE Patents [OSTI]

A mounting apparatus for an electromagnetic device such as a transformer of inductor includes a generally planar metallic plate as a first heat sink, and a metallic mounting cup as a second heat sink. The mounting cup includes a cavity configured to receive the electromagnetic device, the cavity being defined by a base, and an axially-extending annular sidewall extending from the base to a flange portion of the mounting cup. The mounting cup includes first and second passages for allowing the leads of first and second windings of the electromagnetic device to be routed out of the cavity. The cavity is filled with a polyurethane potting resin, and the mounting cup, including the potted electromagnetic device, is mounted to the plate heat sink using fasteners. The mounting cup, which surrounds the electromagnetic device, in combination with the potting resin provides improved thermal transfer to the plate heat sink, as well as providing resistance to vibration and shocks.

Ronning, Jeffrey J. (Fishers, IN)

2002-01-01T23:59:59.000Z

100

Observation of Hybrid Soliton Vortex-Ring Structures in Bose-Einstein Condensates Naomi S. Ginsberg,1,* Joachim Brand,2  

E-Print Network [OSTI]

-Einstein condensates. We examine both their creation via soliton-vortex collisions and their subsequent development into vortex rings (VRs) [7,8] via the Kadomtsev-Petviashvili, or ``snake,'' instability [9]. In this Letter frequencies !z 2 21 Hz and !x !y 3:0!z in our 4-Dee magnetic trap [14]. We work at temperatures well below

Hau, Lene Vestergaard

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


101

Photo of the Week: Controlling Chaos with Magnetic Fields | Department of  

Broader source: Energy.gov (indexed) [DOE]

Controlling Chaos with Magnetic Fields Controlling Chaos with Magnetic Fields Photo of the Week: Controlling Chaos with Magnetic Fields January 18, 2013 - 11:26am Addthis This artistic rendition of "spin vortices" illustrates tiny magnetic vortices that spin according to the polarization of each disk's vortex core. At Argonne National Laboratory, scientists are using alternating magnetic fields to control the behavior of these spin vortices, which are small dots made of iron and nickel. The experiments will help to create new, more efficient magnetic devices -- like the random access memory (RAM) in the device you are using to look at this very photo. Learn more about spin vortices. | Photo courtesy of Sander Munster, Dresden University of Technology.

102

High-frequency vortex dynamics and dissipation of high-temperature superconductors  

Science Journals Connector (OSTI)

The high-frequency vortex dynamics of high-temperature superconductors near the flux-line depinning threshold is investigated based on a thermally activated flux-flow (TAFF) model. Dissipation due to vortex motion driven by a microwave electromagnetic field is studied as a function of the frequency, temperature, dc magnetic field, and microwave power. The generalized TAFF model is also compared to the conventional flux-creep theory and is found qualitatively consistent.

N.-C. Yeh

1991-01-01T23:59:59.000Z

103

Low-temperature vortex dynamics in a high-temperature superconductor  

Science Journals Connector (OSTI)

Magnetic-field gradients in the mixed state of a type-II superconductor are studied using Tl205 nuclear magnetic resonance (NMR) on Tl2Ba2Ca2Cu3O10+?. An anomalous peak was observed in the temperature dependence of the transverse relaxation rate at T/Tc?0.25. We attribute this behavior to magnetic-field flucutations from vortex dynamics. We interpret this behavior as a crossover of the principal time scale for vortex dynamics with that of the NMR experiment, approximately 100 ?s. The temperature dependence of this time scale is discussed.

Y.-Q. Song; S. Tripp; W. P. Halperin; L. Tonge; T. J. Marks

1994-12-01T23:59:59.000Z

104

High Core Electron Confinement Regimes in FTU Plasmas with Low- or Reversed-Magnetic Shear and High Power Density Electron-Cyclotron-Resonance Heating  

Science Journals Connector (OSTI)

Electron temperatures in excess of 8 keV have been obtained by electron-cyclotron-resonance heating on FTU plasmas at peak densities up to 8×1019 m -3. The magnetic shear in the plasma core is low or negative, and the electron heat diffusivity remains at, or below, the Ohmic level (0.2 m 2/s), in spite of the very large heating power density (10–20 MW/m 3) which produces extremely high temperature gradients (up to 120 keV/m). The ion heat transport remains at the neoclassical level.

P. Buratti et al.

1999-01-18T23:59:59.000Z

105

Vortex properties in superconducting Nb/Pd multilayers  

Science Journals Connector (OSTI)

We have investigated the upper critical magnetic field Hc2, the critical current density Jc, and the pinning force Fp in sputtered Nb/Pd multilayers, varying the temperatures T, the Pd thicknesses dPd and the magnetic field H orientation (parallel and perpendicular to the plane of the sample). In perpendicular fields, the vortex dynamics was strongly influenced by grain-boundary pinning. In parallel fields, a peak was observed in the Jc(H) curves for samples with Pd thicknesses dPd>100 Å. After comparing the experimental results with the existing theories, we have related the presence of this peak effect to the matching of vortex kinks with the layered artificial structure.

C. Coccorese; C. Attanasio; L. V. Mercaldo; M. Salvato; L. Maritato; J. M. Slaughter; C. M. Falco; S. L. Prischepa; B. I. Ivlev

1998-04-01T23:59:59.000Z

106

Incoherent interaction of propagating spin waves with precessing magnetic moments  

E-Print Network [OSTI]

The magnetization dynamics of the magnetic vortex state occurring in response to subnanosecond transitions of the externally applied magnetic field was investigated in Ni[subscript 80]Fe[subscript 20](12?nm)/Ir[subscript ...

Ross, Caroline A.

107

On the interaction of mesoscopic magnetic textures with superconductors  

E-Print Network [OSTI]

, and established the required conditions for that. In particular, we studied two configurations for the magnetization distribution, namely the magnetic vortex and magnetic dot. We found that the dot was capable of simultaneously creating vortices...

Kayali, Mohammad Amin

2012-06-07T23:59:59.000Z

108

Vortex lines and transitions in superfluid hydrodynamics  

Science Journals Connector (OSTI)

...Preface to Vortices, dislocations, and line singularities in partial differential equations...Leslie and J. R. Ockendon. Vortex lines and transitions in superfluid hydrodynamics...nature and the motion of qunatized vortex lines. This paper illustrates the transitions...

1997-01-01T23:59:59.000Z

109

Gravity waves from vortex dipoles and jets  

E-Print Network [OSTI]

The dissertation first investigates gravity wave generation and propagation from jets within idealized vortex dipoles using a nonhydrostatic mesoscale model. Several initially balanced and localized jets induced by vortex dipoles are examined here...

Wang, Shuguang

2009-05-15T23:59:59.000Z

110

Monopole-Antimonopole Chains and Vortex Rings  

E-Print Network [OSTI]

We consider static axially symmetric solutions of SU(2) Yang-Mills-Higgs theory. The simplest such solutions represent monopoles, multimonopoles and monopole-antimonopole pairs. In general such solutions are characterized by two integers, the winding number m of their polar angle, and the winding number n of their azimuthal angle. For solutions with n=1 and n=2, the Higgs field vanishes at m isolated points along the symmetry axis, which are associated with the locations of m monopoles and antimonopoles of charge n. These solutions represent chains of m monopoles and antimonopoles in static equilibrium. For larger values of n, totally different configurations arise, where the Higgs field vanishes on one or more rings, centered around the symmetry axis. We discuss the properties of such monopole-antimonopole chains and vortex rings, in particular their energies and magnetic dipole moments, and we study the influence of a finite Higgs self-coupling constant on these solutions.

Burkhard Kleihaus; Jutta Kunz; Yasha Shnir

2004-05-19T23:59:59.000Z

111

New vortex ring configurations for the MAP dyon solutions  

Science Journals Connector (OSTI)

Electrically charged magnetic solutions of SU (2) Yang-Mills-Higgs theory with net zero topological charge has been obtained as axially symmetric saddle-point solutions in Ref. [1]. These solutions are characterized by an integer the winding number n of their azimuthal angle ? and an electric charge parameter 0vortex ring configuration with n=2 ?=0.65 and varying Higgs field strength. Our observations showed that beside the fundamental solution which is an electrically charged MAP solution there also exist two other branches of eclectically charged vortex ring solutions which both appear at ?=20.45. The difference in total energy between these two branches of solution is very small but the difference in diameter of vortex rings of the two branches is quite significant. Finding of a branching phenomena in presence of a fundamental MAP solution has been for the first time. In Ref. [2] new branching solutions occur for the electrically neutral case in presence of fundamental vortex ring solutions but not for the fundamental MAP solution.

2014-01-01T23:59:59.000Z

112

Vortex strings in electric dipole radiation near a mirror  

Science Journals Connector (OSTI)

Abstract The energy flow pattern of the radiation emitted by an oscillating electric dipole near a mirror has a complicated structure, including numerous singularities and vortices. We consider the flow lines of energy in the plane through the surface normal and the oscillation direction of the dipole. It is shown that the vortices are due to the vanishing of the magnetic field at their centers. The locations of the vortices have the appearance of beads on strings, and there are four such strings. The rotation direction of the energy flow for each vortex on a given string is the same. There are two strings with clockwise rotation and two strings with counterclockwise rotation. Field lines of energy flow either start or end at the center of a vortex. For a given string, field lines end at each vortex or field lines start at each vortex. There are two strings on which field lines end at the centers of the vortices, and there are two strings on which field lines start inside the vortices.

Xin Li; Henk F. Arnoldus

2013-01-01T23:59:59.000Z

113

Magnetism  

Science Journals Connector (OSTI)

Historically, magnetism is related to rock magnetism, due to a few minerals exhibiting spontaneous magnetization. Attractive properties of magnetite were already known in Antiquity and were used for navigation...

Guillaume Morin

1998-01-01T23:59:59.000Z

114

Influence of open and sealed fractures on fluid flow and water saturation in sandstone cores using Magnetic Resonance Imaging  

Science Journals Connector (OSTI)

......problems in hydrocarbon production or the safe deep storage of high-level waste. 2 Principles of nmr and mri techniques Nuclear...obtained by coring at surface exposure subject to long-term interaction with the atmosphere, and are hence......

S. Baraka-Lokmane; G. Teutsch; I. G. Main

2001-11-01T23:59:59.000Z

115

magnetism  

Science Journals Connector (OSTI)

magnetism [A class of physical phenomena associated with moving electricity, including the mutual mechanical forces among magnets and electric currents] ? Magnetismus m

2014-08-01T23:59:59.000Z

116

Design of a scanning Josephson junction microscope for submicron-resolution magnetic imaging  

SciTech Connect (OSTI)

We describe a magnetic field scanning instrument designed to extend the spatial resolution of scanning superconducting quantum interference device microscopy into the submicron regime. This instrument, the scanning Josephson junction microscope, scans a single Josephson junction across the surface of a sample, detecting the local magnetic field by the modulation of the junction critical current. By using a submicron junction and a scanning tunneling microscope feedback system to maintain close proximity to the surface, magnetic field sensitivity of 10 {mu}G with a spatial resolution of 0.3 {mu}m should be attainable, opening up new opportunities for imaging vortex configurations and core structure in superconductors and magnetic domains in magnetic materials. {copyright} {ital 1999 American Institute of Physics.}

Plourde, B.L.; Van Harlingen, D.J. [Department of Physics, Science and Technology Center for Superconductivity, and Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States)] [Department of Physics, Science and Technology Center for Superconductivity, and Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States)

1999-11-01T23:59:59.000Z

117

Flame–vortex interaction in a reacting vortex ring  

Science Journals Connector (OSTI)

Direct numerical simulations are used to study the flame–vortex interaction in a laminar reacting vortex ring. The chemical reaction occurs by a one-step Arrhenius-type reaction that mimics the combustion of typical hydrocarbon and air. The ring is generated by an axisymmetric jet that is impulsed to emit a cold fuel through a nozzle. The fuel enters a quiescent ambient at a much higher temperature. By adjusting the ratio of the ambient and fuel temperatures the ignition either occurs during the formation or post-formation phase of the ring. When ignition occurs during the formation phase of the ring the bulk of combustion is by a flame at the front of the vortex bubble. When ignition is delayed until after the formation phase most of the reaction occurs inside the vortex ring. It is found that premixing the fuel and the oxidizer enhances the amount of product formation. The heat released from the reaction significantly affects production redistribution and diffusion of the vorticity throughout the field. The results of the simulations also reveal that the heat of reaction affects the strain rate fields differently depending on when the ignition of the ring occurs.

J. S. Hewett; C. K. Madnia

1998-01-01T23:59:59.000Z

118

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...

119

One-Pot Synthesis of Magnetic Graphene Nanocomposites Decorated with Core@Double-shell Nanoparticles for Fast Chromium  

E-Print Network [OSTI]

(VI) removal from the wastewater with a high removal efficiency and with an almost complete removal of Cr. By using a permanent magnet, the recycling process of both the MGNC adsorbents and the adsorbed Cr for the efficient removal of heavy metals from the wastewater. INTRODUCTION Rapid industrialization has led

Guo, John Zhanhu

120

Moon Rock Reveals Hot Molten Core | Wired Science from Wired.com http://blog.wired.com/wiredscience/2009/01/moon-magnet.html 1 of 4 1/16/2009 2:39 PM  

E-Print Network [OSTI]

Science from Wired.com http://blog.wired.com/wiredscience/2009/01/moon-magnet.html 2 of 4 1/16/2009 2All Wired Moon Rock Reveals Hot Molten Core | Wired Science from Wired.com http://blog.wired.com/wiredscience/2009/01/moon-magnet.html 1 of 4 1/16/2009 2:39 PM #12;« Monkeys Are Gadget Junkies, Too | Main | A New

Weiss, Benjamin P.

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


121

Magnetism  

Science Journals Connector (OSTI)

... dipoles in applied fields". It deals with the classical (Langevin) theory of para-magnetism, anisotropy fields and magnetic measurements. In the next chapter "Atomic structure" the author ... special relevance to ferrites and the inclusion of a quite lengthy discussion of Pauli para-magnetism and of Stoner's treatment of itinerant electron ferromagnetism, though it does much to ...

E. W. LEE

1972-03-31T23:59:59.000Z

122

Vortex molecules in Bose-Einstein condensates  

E-Print Network [OSTI]

Stable vortex dimers are known to exist in coherently coupled two component Bose-Einstein condensates (BECs). We construct stable vortex trimers in three component BECs and find that the shape can be controlled by changing the internal coherent (Rabi) couplings. Stable vortex N-omers are also constructed in coherently coupled N-component BECs. We classify all possible N-omers in terms of the mathematical graph theory. Next, we study effects of the Rabi coupling in vortex lattices in two-component BECs. We find how the vortex lattices without the Rabi coupling known before are connected to the Abrikosov lattice of integer vortices with increasing the Rabi coupling. In this process, vortex dimers change their partners in various ways at large couplings. We then find that the Abrikosov lattices are robust in three-component BECs.

Muneto Nitta; Minoru Eto; Mattia Cipriani

2013-07-16T23:59:59.000Z

123

Reconnection of vortex filaments and Kolmogorov spectrum  

E-Print Network [OSTI]

The energy spectrum of the 3D velocity field, induced by collapsing vortex filaments is studied. One of the aims of this work is to clarify the appearance of the Kolmogorov type energy spectrum $E(k)\\varpropto k^{-5/3}$, observed in many numerical works on discrete vortex tubes (quantized vortex filaments in quantum fluids). Usually, explaining classical turbulent properties of quantum turbulence, the model of vortex bundles, is used. This model is necessary to mimic the vortex stretching, which is responsible for the energy transfer in classical turbulence. In our consideration we do not appeal to the possible "bundle arrangement" but explore alternative idea that the turbulent spectra appear from singular solution, which describe the collapsing line at moments of reconnection. One more aim is related to an important and intensively discussed topic - a role of hydrodynamic collapse in the formation of turbulent spectra. We demonstrated that the specific vortex filament configuration generated the spectrum $E...

Nemirovskii, Sergey K

2014-01-01T23:59:59.000Z

124

Quantum Kinematics of Bosonic Vortex Loops  

SciTech Connect (OSTI)

Poisson structure for vortex filaments (loops and arcs) in 2D ideal incompressible fluid is analyzed in detail. Canonical coordinates and momenta on coadjoint orbits of the area-preserving diffeomorphism group, associated with such vortices, are found. The quantum space of states in the simplest case of ''bosonic'' vortex loops is built within a geometric quantization approach to the description of a quantum fluid. Fock-like structure and non-local creation and annihilation operators of quantum vortex filaments are introduced.

Goldin, G.A.; Owczarek, R.; Sharp, D.H.

1999-05-06T23:59:59.000Z

125

Cherenkov resonances in vortex dissipation in superconductors B. I. Ivlev and S. Mejia-Rosales  

E-Print Network [OSTI]

, Mexico M. N. Kunchur Department of Physics and Astronomy, University of South Carolina, Columbia, South-two superconductors the magnetic flux is carried by vortices. If the transport electric current greatly exceeds in the crystal the dissipa- tion increases due to Cherenkov emission of sound waves. Each moving vortex creates

Kunchur, Milind N.

126

Vortex Hydro Energy Develops Transformational Technology to Harness...  

Energy Savers [EERE]

Vortex Hydro Energy Develops Transformational Technology to Harness Energy from Water Currents Vortex Hydro Energy Develops Transformational Technology to Harness Energy from Water...

127

Core sizes and dynamical instabilities of giant vortices in dilute Bose-Einstein condensates  

SciTech Connect (OSTI)

Motivated by a recent demonstration of cyclic addition of quantized vorticity into a Bose-Einstein condensate, the vortex pump, we study dynamical instabilities and core sizes of giant vortices. The core size is found to increase roughly as a square-root function of the quantum number of the vortex, whereas the strength of the dynamical instability either saturates to a fairly low value or increases extremely slowly for large quantum numbers. Our studies suggest that giant vortices of very high angular momenta may be achieved by gradually increasing the operation frequency of the vortex pump.

Kuopanportti, Pekko; Lundh, Emil; Huhtamaeki, Jukka A. M.; Pietilae, Ville; Moettoenen, Mikko [Department of Applied Physics/COMP, Aalto University School of Science and Technology, P.O. Box 15100, FI-00076 AALTO (Finland); Department of Physics, Umeaa University, SE-90187 Umeaa (Sweden); Department of Applied Physics/COMP, Aalto University School of Science and Technology, P.O. Box 15100, FI-00076 AALTO, Finland and Department of Physics, Okayama University, Okayama 700-8530 (Japan); Department of Applied Physics/COMP, Aalto University School of Science and Technology, P.O. Box 15100, FI-00076 AALTO, Finland and Australian Research Council Centre of Excellence for Quantum Computer Technology, School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney NSW 2052 (Australia); Department of Applied Physics/COMP, Aalto University School of Science and Technology, P.O. Box 15100, FI-00076 AALTO, Finland, Australian Research Council Centre of Excellence for Quantum Computer Technology, School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney NSW 2052 (Australia) and Low Temperature Laboratory, Aalto University School of Science and Technology, P.O. Box 13500, FI-00076 AALTO (Finland)

2010-02-15T23:59:59.000Z

128

Amplitude distribution of magnetoelastic waves propagating in a vortex field in a superconducting layer  

Science Journals Connector (OSTI)

Magnetic field enters the type ? II superconducting body along a discrete arrangement of magnetic vortex lines. In the dynamic case when the magnetic field vary in time around each such a line a supercurrent flows. So the vorticesinteract one to another with the help of the Lorentz force forming this way a new mechanical field of elastic properties. Moreover those lines arrange themselves in a triangular or quadratic lattice. Such a set is observed if the intensity of the applied to the materialmagnetic field is close to its lower limiting value. The paper aims at investigating amplitude distributions of magnetoelastic waves propagating solely in the vortex field of the superconducting layer. Our attention have been focused on the applied magnetic field intensity influence on those amplitudes for various wave frequencies.

Bogdan T. Maruszewski; Andrzej Drzewiecki; Roman Starosta

2008-01-01T23:59:59.000Z

129

Spontaneous vortex phase and pinning in ferromagnetic-superconducting systems  

E-Print Network [OSTI]

of epsilon10 as a function of rho0lambda for the case when n = 1, lambdaxi = 10,R1 = lambda,R2 = 2lambda and deltam = 10. . . . . . . . . . . . . . . 31 ix FIGURE Page 12 A superconducting thin film pierced by a ferromagnetic nano rod of radius R, length L... circle of radius rho0 that depends on the radii and magnetization per unit area of the annulus, and on the SC pene- tration depth lambda. In section five I focus on pinning and spontaneous vortex creation by a ferromagnetic rod which penetrates...

Kayali, Mohammad Amin

2004-09-30T23:59:59.000Z

130

Magnetism  

Science Journals Connector (OSTI)

... THIS is a good book, and we are glad to see the subject of magnetism fully treated in a popularly written text-book. It is a second edition of ... of importance, accuracy, and exhaustiveness, places the present treatise, as far as terrestrial magnetism is concerned, much before any similar book with which we are acquainted. The correction ...

JAMES STUART

1872-03-07T23:59:59.000Z

131

Characterization of The Dalles Dam Spillbay 6 Vortex Using Surface Entrained Sensor Fish Device: Preliminary Report  

SciTech Connect (OSTI)

This document summarizes the pilot study to characterize The Dalles Dam Spillbay 6 vortex using a surface entrained Sensor Fish device. It was conducted by Pacific Northwest National Laboratory (PNNL) on April 13 and 14, 2006. The total spill was controlled at approximately 110 kcfs, the forebay elevation was 157.89 ft, and the discharge of Bay 6 at the tested gate opening of 14 ft was approximately 18 kcfs. The objectives of the full study are to (1) develop baseline conditions for the detailed analysis of Sensor Fish measurements by deploying Sensor Fish in different surface locations in the vortex periphery; (2) observe the entrainment pattern and extract hydraulic data of interest such as acceleration, rotation, pressure, and estimated velocity of Sensor Fish or drogues; (3) integrate the experimental results with companion computational fluid dynamics (CFD) simulations and inertial particle tracking studies. A total of 12 Sensor Fish were released in the surface at upstream edge, left edge, downstream edge, and the core of the vortex at Bay 6. Because of the high discharge, the vortex patterns at the test condition were less consistent than the patterns observed at lower discharges. Compared with the Sensor Fish released at mid-bay at Bay 6, Sensor Fish released from the surface at the vortex experienced higher pressure fluctuations, a larger percentage of severe events, and much more rapid angular velocities.

Deng, Zhiqun; Richmond, Marshall C.; Carlson, Thomas J.

2006-06-22T23:59:59.000Z

132

The idea of vortex energy  

E-Print Network [OSTI]

This work formulates and gives grounds for general principles and theorems that question the energy function doctrine and its quantum version as a genuine law of nature without borders of adequacy. The emphasis is on the domain where the energy of systems is conserved -- I argue that only in its tiny part the energy is in the kinetic, potential and thermal forms describable by a generalized thermodynamic potential, whereas otherwise the conserved energy constitutes a whole linked to vortex forces, and can be a factor of things like persistent currents and dark matter.

V. E. Shapiro

2011-09-22T23:59:59.000Z

133

The dramatic change of the fossil magnetic field of HD 190073: evidence of the birth of the convective core in a Herbig star ?  

E-Print Network [OSTI]

In the context of the ESPaDOnS and Narval spectropolarimetric surveys of Herbig Ae/Be stars, we discovered and then monitored the magnetic field of HD 190073 over more than four years, from 2004 to 2009. Our observations all displayed similar Zeeman signatures in the Stokes V spectra, indicating that HD 190073 hosted an aligned dipole, stable over many years, consistent with a fossil origin. We obtained new observations of the star in 2011 and 2012 and detected clear variations of the Zeeman signature on timescales of days to weeks, indicating that the configuration of its field has changed between 2009 and 2011. Such a sudden change of external structure of a fossil field has never previously been observed in any intermediate or high-mass star. HD 190073 is an almost entirely radiative pre-main sequence star, probably hosting a growing convective core. We propose that this dramatic change is the result of the interaction between the fossil field and the ignition of a dynamo field generated in the newly-born ...

Alecian, E; Mathis, S; Catala, C; Kochukhov, O; Landstreet, J

2013-01-01T23:59:59.000Z

134

Interaction of mesoscopic magnetic textures with superconductors  

E-Print Network [OSTI]

Here we report a method to calculate the vortex and magnetization arrangement for a system of interacting superconductors and ferromagnets separated in space. The method is based on static London-Maxwell equations and the corresponding energy...

Erdin, S.; Kayali, AF; Lyuksyutov, Igor F.; Pokrovsky, Valery L.

2002-01-01T23:59:59.000Z

135

Stability of vortex solitons in a photorefractive optical lattice  

E-Print Network [OSTI]

://www.njp.org/ DOI: 10.1088/1367-2630/6/1/047 Abstract. Stability of on- and off-site vortex solitons with unit stable than off-site ones. Increasing the DC field stabilizes both types of vortex solitons. Contents 1. Introduction 2 2. Off-site vortex solitons 4 3. On-site vortex solitons 9 4. Summary 11 Acknowledgments 11

Yang, Jianke

136

Reversal modes in magnetic nanotubes  

E-Print Network [OSTI]

The magnetic switching of ferromagnetic nanotubes is investigated as a function of their geometry. Two independent methods are used: Numerical simulations and analytical calculations. It is found that for long tubes the reversal of magnetization is achieved by two mechanism: The propagation of a transverse or a vortex domain wall depending on the internal and external radii of the tube.

P. Landeros; S. Allende; J. Escrig; E. Salcedo; D. Altbir; E. E. Vogel

2006-11-08T23:59:59.000Z

137

Core Specialization  

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

Core Specialization Core Specialization Core Specialization Core Specialization (CS) is a feature of the Cray operating system that allows the user to reserve one or more cores per node for handling system services, and thus reduce the effects of timing jitter due to interruptions from the operating system at the expense of (possibly) requiring more nodes to run an application. The specialized cores may also be used in conjunction with Cray's MPI asynchronous progress engine [1] to improve the overlap of communication and computation for applications that use non-blocking MPI functions. In the absence of CS, the compute cores must service their own non-blocking calls. Hyper-Threading complicates questions abouty the most effective use of processor resources. HT doubles the number of compute stream (i.e.

138

Core Specialization  

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

Core Core Specialization Core Specialization Core Specialization (CS) is a feature of the Cray operating system that allows the user to reserve one or more cores per node for handling system services, and thus reduce the effects of timing jitter due to interruptions from the operating system at the expense of (possibly) requiring more nodes to run an application. The specialized cores may also be used in conjunction with Cray's MPI asynchronous progress engine [1] to improve the overlap of communication and computation for applications that use non-blocking MPI functions. In the absence of CS, the compute cores must service their own non-blocking calls. Hyper-Threading complicates questions abouty the most effective use of processor resources. HT doubles the number of compute stream (i.e.

139

Particle resuspension by an impacting vortex ring  

Science Journals Connector (OSTI)

Coherent vortex structures play a significant and important role in the dynamics of many commonly occurring natural flows, for example turbulent boundary layers and channel flows. One particularly important fe...

Rick J. Munro; Stuart B. Dalziel

2003-01-01T23:59:59.000Z

140

‘Optimal’ vortex rings and aquatic propulsion mechanisms  

Science Journals Connector (OSTI)

...vortex rings and aquatic propulsion mechanisms P. F. Linden...fluid mechanics behind these propulsion mechanisms and show that...over the cycle. 4. FISH PROPULSION BY UNDULATORY SWIMMING Most marine organisms have only discrete...

2004-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "magnetic vortex core" 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

Polarization dependent forces in optical vortex pipeline  

Science Journals Connector (OSTI)

We study both, theoretically and in experiments, the dependence of optical forces acting on a spherical particle guided in air with an optical vortex beam, on the light polarization...

Eckerskorn, Niko; Krolikowski, Wieslaw; Shvedov, Vladlen; Rode, Andrei

142

Airfoil Vortex Induced Vibration suppression devices  

E-Print Network [OSTI]

Vortex Induced Vibrations (VIV) is a major concern of the offshore oil industry. This problem leads to fatigue failure in the marine risers and causes costly replacement of the risers. Appendages such as helical strakes ...

Lee, Evan J. (Evan Joseph)

2007-01-01T23:59:59.000Z

143

Holographic Vortex Liquids and Superfluid Turbulence  

Science Journals Connector (OSTI)

...of Kelvin waves flowing along vortex strings in 3D quantum turbulence...theory correlators from non-critical string theory . Phys. Lett. B...S. , Emergence of turbulence in an oscillating Bose-Einstein condensate . Phys. Rev...

Paul M. Chesler; Hong Liu; Allan Adams

2013-07-26T23:59:59.000Z

144

magnets  

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

I I Painless Physics Articles BEAM COOLING August 2, 1996 By Leila Belkora, Office of Public Affairs ACCELERATION August 16, 1996 By Dave Finley, Accelerator Division Head RF August 30, 1996 By Pat Colestock, Accelerator Division FIXED TARGET PHYSICS September 20, 1996 By Peter H. Garbincius, Physics Section FIXED TARGET PHYSICS PART DEUX October 16, 1996 By Peter H. Garbincius, Physics Section and Leila Belkora, Office of Public Affaris CROSS SECTION November 1, 1996 By Doreen Wackeroth, Theoretical Physics Edited by Leila Belkora, Office of Public Affaris MAGNETS PART I November 15, 1996 By Hank Glass, Technical Support Section Edited by Donald Sena, Office of Public Affairs MAGNETS PART II January 10, 1997 By Hank Glass, Technical Support Section Edited by Donald Sena, Office of Public Affairs

145

Magnetorotational instability, current relaxation, and current-vortex sheet  

SciTech Connect (OSTI)

The conjugate effect of current relaxation and of current-vortex sheet formation on the magnetorotational instability is explored in a conducting fluid. It is found that the relative amplification of the magnetic viscosity from marginal stability to the instability determined by the maximum growth rate is around 924% when resistive effects dominate, while the corresponding quantity is around 220% in the ideal limit. This shows that the conjugate influence is much more efficient to amplify the magnetic viscosity than just the effect due to the standard magnetic tension. It is also found that the magnitude of the magnetic viscosity is effectively enhanced by the conjugate influence. The results presented here may contribute to the understanding of the various processes that play a significant role in the mechanism of anomalous viscosity observed in Keplerian disks. It is argued that the new effect shall be relevant in thin accretion disks. It is also mentioned that the proposed formulation may be of interest for some theories of magnetic reconnection. Possible extensions of this work are suggested.

Silveira, F. E. M. [Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Rua Santa Adélia, 166, CEP 09210-170, Bairro Bangu, Santo André, SP (Brazil)] [Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Rua Santa Adélia, 166, CEP 09210-170, Bairro Bangu, Santo André, SP (Brazil); Galvão, R. M. O. [Instituto de Física, Universidade de São Paulo, Rua do Matão, Travessa R, 187, CEP 05508-090, Cidade Universitária, São Paulo, SP (Brazil)] [Instituto de Física, Universidade de São Paulo, Rua do Matão, Travessa R, 187, CEP 05508-090, Cidade Universitária, São Paulo, SP (Brazil)

2013-08-15T23:59:59.000Z

146

Reconnection of vortex filaments and Kolmogorov spectrum  

E-Print Network [OSTI]

The energy spectrum of the 3D velocity field, induced by collapsing vortex filaments is studied. One of the aims of this work is to clarify the appearance of the Kolmogorov type energy spectrum $E(k)\\varpropto k^{-5/3}$, observed in many numerical works on discrete vortex tubes (quantized vortex filaments in quantum fluids). Usually, explaining classical turbulent properties of quantum turbulence, the model of vortex bundles, is used. This model is necessary to mimic the vortex stretching, which is responsible for the energy transfer in classical turbulence. In our consideration we do not appeal to the possible "bundle arrangement" but explore alternative idea that the turbulent spectra appear from singular solution, which describe the collapsing line at moments of reconnection. One more aim is related to an important and intensively discussed topic - a role of hydrodynamic collapse in the formation of turbulent spectra. We demonstrated that the specific vortex filament configuration generated the spectrum $E(k)$ close to the Kolmogorov dependence and discussed the reason for this as well as the reason for deviation. We also discuss the obtained results from point of view of the both classical and quantum turbulence.

Sergey K. Nemirovskii

2014-04-19T23:59:59.000Z

147

Calorimetric study of the transitions between the different vortex states in YBa{sub 2}Cu{sub 3}O{sub 7}.  

SciTech Connect (OSTI)

We have studied the vortex phase diagram of YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} (YBCO) in very strong magnetic field (0-26 Tesla) by a.c. calorimetry. We describe the anomalies associated with the transitions between the different vortex states (solid, liquid, and glass), with special emphasis on the first order flux lattice melting.

Bouquet, F.; Calemczuk, R.; Crabtree, G. W.; Erb, A.; Fisher, R. A.; Junod, A.; Kwok, W. K.; Marcenat, C.; Phillips, N. E.; Roulin, M.; Schilling, A.; Welp, U.

1999-08-17T23:59:59.000Z

148

Magnetic properties of small multi-layered rings  

E-Print Network [OSTI]

Thin film rings can be an alternative geometry of magnetic memory cells, in which data bits are stored by the chirality of the flux-closed or 'vortex' state of the ring. The absence of the stray field in the vortex state ...

Jung, Wonjoon

2007-01-01T23:59:59.000Z

149

MAP, MAC, and Vortex-rings Configurations in the Weinberg-Salam Model  

E-Print Network [OSTI]

We report on the presence of new axially symmetric monopoles, antimonopoles and vortex-rings solutions of the SU(2)$\\times$U(1) Weinberg-Salam model of electromagnetic and weak interactions. When the $\\phi$-winding number $n=1$, and 2, the configurations are monopole-antimonopole pair (MAP) and monopole-antimonopole chain (MAC) with poles of alternating sign magnetic charge arranged along the $z$-axis. Vortex-rings start to appear from the MAP and MAC configurations when the winding number $n=3$. The MAP configurations possess zero net magnetic charge whereas the MAC configurations possess net magnetic charge of $4\\pi n/e$. In the MAP configurations, the monopole-antimonopole pair is bounded by the ${\\cal Z}^0$ field flux string and there is an electromagnetic current loop encircling it. The monopole and antimonopole possess magnetic charges $\\pm\\frac{2\\pi n}{e}$ respectively. In the MAC configurations there is no string connecting the monopole and the adjacent antimonopole and they possess magnetic charges $\\pm\\frac{4\\pi n}{e}$ respectively. The MAC configurations possess infinite total energy and zero magnetic dipole moment whereas the MAP configurations which are actually sphalerons possess finite total energy and magnetic dipole moment. The configurations were investigated for varying value of Higgs boson mass $0\\leq M_H^2\\leq 80$ at Weinberg angle $\\theta_W=\\frac{\\pi}{4}$.

Rosy Teh; Ban-Loong Ng; Khai-Ming Wong

2014-08-20T23:59:59.000Z

150

Vortex precession frequency and its amplitude-dependent shift in cylindrical nanomagnets  

SciTech Connect (OSTI)

Frequency of free magnetic vortex precession in circular soft ferromagnetic nano-cylinders (magnetic dots) of various sizes is an important parameter, used in design of spintronic devices (such as spin-torque microwave nano-oscillators) and characterization of magnetic nanostructures. Here, using a recently developed collective-variable approach to non-linear dynamics of magnetic textures in planar nano-magnets, this frequency and its amplitude-dependent shift are computed analytically and plotted for the full range of cylinder geometries. The frequency shift is positive in large planar dots, but becomes negative in smaller and more elongated ones. At certain dot dimensions, a zero frequency shift is realized, which can be important for enhancing frequency stability of magnetic nano-oscillators.

Metlov, Konstantin L., E-mail: metlov@fti.dn.ua [Donetsk Institute for Physics and Technology NAS, Donetsk 83114 (Ukraine)

2013-12-14T23:59:59.000Z

151

In-situ magnetization of NdFeB magnets for permanent magnet machines  

SciTech Connect (OSTI)

In-situ magnetizers are needed to facilitate the assembly of permanent magnet machines and to remagnetize the magnets after weakening due to a fault condition. The air-core magnetizer in association with the silicon steel lamination structure of the rotor has advantages over its iron-core counterpart. This novel method has been used to magnetize the NdFeB magnets in a 30-hp permanent magnet synchronous motor. The magnetizing capability for different magnetizer geometries was investigated for the magnetization of NdFeB material. The design, testing, and operation of this magnetizer are reported in this paper.

Chang, L.; Eastham, T.R.; Dawson, G.E. (Dept. of Electrical Engineering, Queen's Univ., Kingston, Ontario K7L 3N6 (CA))

1991-09-01T23:59:59.000Z

152

Fabrication and Characterization of Nano-Sized Magnetic Structures and Their Flux-Pinning Effects on Superconducting Thin Films  

E-Print Network [OSTI]

Energy Dissipation due to Vortex Motion .................................. 7 Vortex Pinning in the Ferromagnet-Superconductor Hybrid (FSH) . 9 II FABRICATION OF EMBEDDED FERROMAGNET..., as the external magnetic field increases above the lower critical field and below an upper critical field ??2 (?), the magnetic flux partially penetrates the sample in the form of tubes, or vortices (Fig.4). This state is said to be a vortex state or mixed...

Lee, Han Gil

2011-02-22T23:59:59.000Z

153

Vortex and gap generation in gauge models of graphene  

E-Print Network [OSTI]

Effective quantum field theoretical continuum models for graphene are investigated. The models include a complex scalar field and a vector gauge field. Different gauge theories are considered and their gap patterns for the scalar, vector, and fermion excitations are investigated. Different gauge groups lead to different relations between the gaps, which can be used to experimentally distinguish the gauge theories. In this class of models the fermionic gap is a dynamic quantity. The finite-energy vortex solutions of the gauge models have the flux of the "magnetic field" quantized, making the Bohm-Aharonov effect active even when external electromagnetic fields are absent. The flux comes proportional to the scalar field angular momentum quantum number. The zero modes of the Dirac equation show that the gauge models considered here are compatible with fractionalization.

O. Oliveira; C. E. Cordeiro; A. Delfino; W. de Paula; T. Frederico

2010-12-21T23:59:59.000Z

154

Vortex Hydro Energy LLC | Open Energy Information  

Open Energy Info (EERE)

Hydro Energy LLC Hydro Energy LLC Jump to: navigation, search Name Vortex Hydro Energy LLC Address 4870 West Clark Rd Suite 108 Place Ypsilanti Zip 48197 Sector Marine and Hydrokinetic Phone number 734.971.4020 Website http://www.vortexhydroenergy.c Region United States LinkedIn Connections CrunchBase Profile No CrunchBase profile. Create one now! This company is listed in the Marine and Hydrokinetic Technology Database. This company is involved in the following MHK Projects: Marine Hydrodynamics Laboratory at the University of Michigan This company is involved in the following MHK Technologies: Vortex Induced Vibrations Aquatic Clean Energy VIVACE This article is a stub. You can help OpenEI by expanding it. Retrieved from "http://en.openei.org/w/index.php?title=Vortex_Hydro_Energy_LLC&oldid=678497

155

Sediment resuspension and erosion by vortex rings  

Science Journals Connector (OSTI)

Particle resuspension and erosion induced by a vortex ringinteracting with a sediment layer was investigated experimentally using flow visualization (particle image velocimetry) high-speed video and a recently developed light attenuation method for measuring displacements in bed level. Near-spherical sediment particles were used throughout with relative densities of 1.2–7 and diameters ( d ) ranging between 90 and 1600 ? ? m . Attention was focused on initially smooth horizontal bedforms with the vortex ring aligned to approach the bed vertically. Interaction characteristics were investigated in terms of the dimensionless Shields parameter defined using the vortex-ring propagation speed. The critical conditions for resuspension (whereby particles are only just resuspended) were determined as a function of particle Reynolds number (based on the particle settling velocity and d ). The effects of viscous damping were found to be significant for d / ? resuspension volumes are analyzed as a function interaction time impact condition and sediment size.

R. J. Munro; N. Bethke; S. B. Dalziel

2009-01-01T23:59:59.000Z

156

Vortex reconnections between coreless vortices in binary condensates  

SciTech Connect (OSTI)

Vortex reconnections plays an important role in the turbulent flows associated with the superfluids. To understand the dynamics, we examine the reconnections of vortex rings in the superfluids of dilute atomic gases confined in trapping potentials using Gross-Petaevskii equation. Further more we study the reconnection dynamics of coreless vortex rings, where one of the species can act as a tracer.

Gautam, S. [Indian Institute of Science, Bangalore-560 012 (India); Suthar, K.; Angom, D. [Physical Research Laboratory, Ahmedabad-380 009 (India)

2014-02-11T23:59:59.000Z

157

PHYSICS OF FLUIDS 24, 125108 (2012) Quantum vortex reconnections  

E-Print Network [OSTI]

is continuous, not discrete, and parts of the initial vortical tubes can be left behind as vortex threads, whichPHYSICS OF FLUIDS 24, 125108 (2012) Quantum vortex reconnections S. Zuccher,1 M. Caliari,1 A. W that the minimum distance between vortices scales differently with time before and after the vortex reconnection

Zuccher, Simone

158

Recent lunar magnetism  

E-Print Network [OSTI]

The magnetization of young lunar samples (magnetic fields (e.g. core dynamo and long-lived impact plasma fields) have not been present within the last 1.5 Ga. To better ...

Buz, Jennifer

2011-01-01T23:59:59.000Z

159

866 IEEE TRANSACTIONS ON MAGNETICS, VOL. 44, NO. 6, JUNE 2008 Dynamical Models for Eddy Current in Ferromagnetic Cores Introduced in  

E-Print Network [OSTI]

is composed of a magnet, a mas- sive circuit, a mobile vane linked to a spring, and a coil. Fig. 1 shows a current appears in the coil, the force created by the spring becomes inferior to the one created by the magnet and the coil; thus, the relay trips. A. Modeling of the Device Thanks to 3-D nonlinear FE model

Boyer, Edmond

160

Not All Nanodisk Magnetic Vortices Are Created Equally  

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

T. Sato, S. Kasai, Y. Nakatani, and T. Ono, "Symmetry breaking in the formation of magnetic vortex states in a permalloy nanodisk," Nat. Comm. 3, 983 (2012). ALS Science...

Note: This page contains sample records for the topic "magnetic vortex core" 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

Correlated vortex pinning in slightly orthorhombic twinned Ba(Fe1-xCox)2As2 single crystals: Possible shift of the vortex-glass/liquid transition  

SciTech Connect (OSTI)

The interest in twin-boundary (TB) planes as a source of vortex pinning has been recently renewed with the discovery of the new iron-arsenide pnictide superconductors. In the family of compounds Ba(Fe1-xCox)2As2 a structural transition from a tetragonal to orthorhombic lattice takes place for compounds with xvortex cores. In this work we investigate the changes in anisotropy produced by subtle differences in the Co doping level, in the neighborhood of the structural transition, in good-quality single crystals. Using a scaling approach we are able to determine the angular regions where correlated or uncorrelated disorder prevails. In the tetragonal samples (x>xcr) there is no twinning and we find good agreement with the expected scaling function under uncorrelated disorder, with small anisotropy values similar to those reported in the literature. We show that in the orthorhombic samples (xvortex liquid-glass transition temperature.

Bermudez, M. Marziali [Universidad de Buenos Aires; Pasquini, G. [Universidad de Buenos Aires; Budko, Sergey L. [Ames Laboratory; Canfield, Paul C. [Ames Laboratory

2013-02-28T23:59:59.000Z

162

Dynamic core length in saturated core fault current limiters  

Science Journals Connector (OSTI)

A saturated core fault current limiter (SCFCL) is a non-linear core-reactor where the core is saturated by an external superconducting DC bias source to achieve a low core permeability at nominal AC currents. Fault current levels in the AC coils de-saturate the core and transform it to a higher permeability state, hence limiting the fault current. In this work we describe the transition between saturated and de-saturated states in three SCFCL configurations. The 'effective core length', Leff, of the SCFCL, defined as the length of the de-saturated AC core limb, is introduced for exploring this transition as a function of the current, I, in the AC coil. Practically, Leff allows one to see the SCFCL as an inductor with a variable core length, allowing calculations of the impedance of the SCFCL over the whole range of operating currents. The Leff(I) curve is further used to calculate the dynamics of the demagnetization factor in a SCFCL. We show that the strong change in the magnetic induction of a SCFCL at high current is the result of both increasing the effective core length and decreasing the demagnetization factor. The method and results presented here serve as an important tool for comparing between various SCFCL concepts not only by comparing their impedance values at the extreme fault and nominal current conditions but also by providing an insight into the full de-saturation process.

Y Nikulshin; Y Wolfus; A Friedman; Y Yeshurun

2013-01-01T23:59:59.000Z

163

Jammed vortex matter Hajime Yoshino1  

E-Print Network [OSTI]

. Abstract: Irrationally frustrated Josephson junction array (JJA), namely JJA with irrational number density point. Figure 1: Josephson junction array (JJA) on a square lattice. The vertexes and bonds represent- not develop usual periodic vortex lattices. 1 Introduction Josephson junction array under mag- netic field

Katsumoto, Shingo

164

Vortex Jitter in Hover Swathi M. Mula  

E-Print Network [OSTI]

78712, USA Abstract The trajectory of the tip vortex of a reduced-scale, 1 m diameter, four-bladed rotor condition of the rotor is at a blade loading of CT / = 0.0645 and a rotational speed of 1240RPM wake dominated by the tip vortices shed from the rotor blades. The complexity of the flow

Tinney, Charles E.

165

The multiple vortex nature of tropical cyclogenesis  

E-Print Network [OSTI]

) __________________________ __________________________ John Nielsen-Gammon Craig Epifanio (Chair of Committee) (Member) __________________________ __________________________ Fuqing Zhang Hongxing Liu (Member) (Member) December 2004 Major Subject: Atmospheric Sciences... iii ABSTRACT The Multiple Vortex Nature of Tropical Cyclogenesis. (December 2004) Jason Allen Sippel, B.S., Texas A&M University Chair of Advisory Committee: Dr. John Nielsen-Gammon This thesis contains an observational analysis...

Sippel, Jason Allen

2005-02-17T23:59:59.000Z

166

Quenching Processes in Flame-Vortex Interactions  

E-Print Network [OSTI]

for Astrophysical Thermonuclear Flashes 1 , Chicago, IL 60637 y Department of Astronomy and Astrophysics, University-vortex interactions in order to understand quenching of thermonuclear ames. The key question is|can a ther- monuclear. If a ame encounters a 1) The Center for Astrophysical Thermonuclear Flashes is supported by the Department

Zingale, Michael

167

Vortex dynamics in 4 Banavara N. Shashikanth  

E-Print Network [OSTI]

during the interaction of a pair of counter-rotating vortices Phys. Fluids 24, 014107 (2012) The onset of oblique vortex shedding behind a heated circular cylinder in laminar wake regime Phys. Fluids 24, 011701 fluids Phys. Fluids 23, 115106 (2011) Asymptotic properties of wall-induced chaotic mixing in point

Shashikanth, Banavara N.

168

A Brief Note on Jupiter's Magnetism  

E-Print Network [OSTI]

A recent model which gives the contribution of the earth's solid core to geo magnetism is seen to explain Jupiter's magnetism also.

B. G. Sidharth

1999-05-06T23:59:59.000Z

169

High voltage dry-type air-core shunt reactors  

Science Journals Connector (OSTI)

Dry-type air-core shunt reactors are now being ... systems to limit overvoltages. Recently, high voltage dry-type air-core shunt reactors have been designed, ... transient overvoltages and electrical and magnetic...

Klaus Papp; Michael R. Sharp…

2014-11-01T23:59:59.000Z

170

Remarks on Terrestrial Magnetism  

Science Journals Connector (OSTI)

... auror are secondary currents produced by rapid, though small, changes in the earth's magnetism. In this hypothesis the earth was viewed as similar to the soft iron core ... conductors in which secondary currents would be generated whenever any change took place in the magnetism of the core.

B. STEWART

1870-01-06T23:59:59.000Z

171

A Vortex Contactor for Carbon Dioxide Separations  

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

Vortex Contactor for Carbon Dioxide Separations Vortex Contactor for Carbon Dioxide Separations Kevin T. Raterman (ratekt@inel.gov; 208-526-5444) Michael McKellar (mgq@inel.gov; 208-526-1346) Anna Podgorney (poloak@inel.gov; 208-526-0064) Douglas Stacey (stacde@inel.gov; 208-526-3938) Terry Turner (tdt@inel.gov; 208-526-8623) Idaho National Engineering and Environmental Laboratory P.O. Box 1625 Idaho Falls, Idaho 83415-2110 Brian Stokes (bxs9@pge.com; 415-972-5591) John Vranicar (jjv2@pge.com; 415-972-5591) Pacific Gas & Electric Company 123 Mission Street San Francisco, CA 94105 Introduction Many analysts 1,2,3 identify carbon dioxide (CO 2 ) capture and separation as a major roadblock in efforts to cost effectively mitigate greenhouse gas emissions via sequestration. An assessment 4 conducted by the International Energy Agency (IEA)

172

Acceleration and vortex filaments in turbulence  

E-Print Network [OSTI]

We report recent results from a high resolution numerical study of fluid particles transported by a fully developed turbulent flow. Single particle trajectories were followed for a time range spanning more than three decades, from less than a tenth of the Kolmogorov time-scale up to one large-eddy turnover time. We present some results concerning acceleration statistics and the statistics of trapping by vortex filaments.

F. Toschi; L. Biferale; G. Boffetta; A. Celani; B. J. Devenish; A. Lanotte

2005-01-23T23:59:59.000Z

173

Jet?vortex Interaction: A Numerical Study  

Science Journals Connector (OSTI)

The interaction of a vortex and a jet plays an important role for many industrial processes such as Carbon Black formation or combustion in diesel engines. The knowledge of physics of these phenomena is crucial for engineers but also for scientists who wish to reveal many interesting and complex issues hidden there. In this research we numerically investigate cases where a cylindrical reactor is charged with gas injected through five ports. The first one is located along the main axis of the cylinder and this leads to the formation of the main jet. The other four ports are situated along the side walls such that the gas entering the cylinder tangentially through them causes a vortex to be formed. The objective of this paper is to show the fundamental physical phenomena and also how the initial and boundary conditions influence the results. Our most important observation at this stage is that the mixing process is more intense if the vortex is inclined towards x?axis. The results are mainly shown as snapshots of gas velocity.

Catalin G. Ilea; Pawel Kosinski; Alex C. Hoffmann

2009-01-01T23:59:59.000Z

174

Novel Vortex Generator and Mode Converter for Electron Beams  

Science Journals Connector (OSTI)

A mode converter for electron vortex beams is described. Numerical simulations, confirmed by experiment, show that the converter transforms a vortex beam with a topological charge m=±1 into beams closely resembling Hermite-Gaussian HG10 and HG01 modes. The converter can be used as a mode discriminator or filter for electron vortex beams. Combining the converter with a phase plate turns a plane wave into modes with topological charge m=±1. This combination serves as a generator of electron vortex beams of high brilliance.

P. Schattschneider; M. Stöger-Pollach; J. Verbeeck

2012-08-22T23:59:59.000Z

175

Energy Separation And Lox Separation Studies In Vortex Tubes.  

E-Print Network [OSTI]

??Vortex Tube (VT) is a simple device having no moving mechanical parts, in which compressed gas at high pressure is injected through one or more… (more)

Behera, Upendra

2011-01-01T23:59:59.000Z

176

Vortex motion rectification in Josephson junction arrays with a ratchet potential  

E-Print Network [OSTI]

By means of electrical transport measurements we have studied the rectified motion of vortices in ratchet potentials engineered on over-damped Josephson junction arrays. The rectified voltage as a function of the vortex density shows a maximum efficiency close a matching condition to the period of the ratchet potential indicating a collective vortex motion. Vortex current reversals where detected varying the driving force and vortex density revealing the influence of vortex-vortex interaction in the ratchet effect.

D. E. Shalom; H. Pastoriza

2004-11-19T23:59:59.000Z

177

An application of vortex cancellation to vortex generator techniques in low speed wind tunnels  

E-Print Network [OSTI]

'lugs/ft-sec Axial distance between sets of vortex generators root chord lengths /Y Vertical dimension of duct cross section Tube height/Y in. none ~St i t ()i ()2 (), ( )?q Measured at station g 1 Measured at Station 0 8 Upstream srl... TABLE I II BOUNDARY LAYER PROFILE DATA IN THE VICINITY OF A VORTEX FILAMENT AT STATION 0 7 Tube Number I 2 3 4. 5 6 7 8 9 '10 I 2 3 4 5 6 7 8 9 10 I 2 3 4 5 6 7 8 9 10 Ft-Fs in. H 0 1. 31 1. 31 1. 31 I . 26 1. 20...

Mount, Glynn O., Jr

2012-06-07T23:59:59.000Z

178

E-Print Network 3.0 - advanced vortex element Sample Search Results  

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

method of plasma Summary: with the new simple explanation of the energy separation in vortex tubes described here. Advanced numerical... vortex method of plasma insulation and...

179

E-Print Network 3.0 - accelerated vortex ring Sample Search Results  

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

left behind... forces were derived from the vortex rings, assuming all propulsive energy to be compiled in the rings... , ending up in a separate vortex ... Source:...

180

Transverse energy circulation and the edge diffraction of an optical vortex beam  

Science Journals Connector (OSTI)

Edge diffraction of a circular Laguerre–Gaussian beam represents an example of the optical vortex symmetry breakdown in which the hidden “vortex” energy...

Bekshaev, Aleksandr Ya; Mohammed, Kadhim A; Kurka, Ivan A

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "magnetic vortex core" 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

Mechanical (acoustic?like) wave propagation along a vortex array in the superconducting heterostructure  

Science Journals Connector (OSTI)

Magnetic flux can penetrate the type ? II superconductor in the form of Abrikosov vortices (also called flux lines flux tubes or fluxons) each carrying a quantum of magnetic flux. These tiny vortices of supercurrent tend to arrange themselves in a triangular or quadratic flux?line lattice. Since the vortices are formed by the applied magnetic field around of each of them the supercurrent flows. Moreover there also exist some Lorentz force interactions among them. Those interactions form an origin of an additional mechanical (stress) field occurring in the type?II superconductor. The paper deals with an analysis of elastic (acoustic?like) wave propagation solely along vortices in a heterostructure consisted of the superconducting layer put on the superconducting substrate. Dispersion and the amplitude distribution of those waves in the vortex field existing in that structure has been presented.

Bogdan T. Maruszewski; Andrzej Drzewiecki; Roman Starosta

2008-01-01T23:59:59.000Z

182

Finned Tube With Vortex Generators For A Heat Exchanger.  

DOE Patents [OSTI]

A system for and method of manufacturing a finned tube for a heat exchanger is disclosed herein. A continuous fin strip is provided with at least one pair of vortex generators. A tube is rotated and linearly displaced while the continuous fin strip with vortex generators is spirally wrapped around the tube.

Sohal, Monohar S. (Idaho Falls, ID); O'Brien, James E. (Idaho Falls, ID)

2004-09-14T23:59:59.000Z

183

ENERGY LEVEL SPECTROSCOPY OF A BOUND VORTEX-ANTIVORTEX PAIR  

E-Print Network [OSTI]

vortex- antivortex (VAV) state in an annular Josephson junction. The bound VAV pair is formed microwave spectroscopy. Keywords: Macroscopic quantum effects, long Josephson junctions, vortex­9]. Most of the studied systems, such as dc-biased Josephson junctions (JJ), supercon- ducting quantum

Wallraff, Andreas

184

Non-equilibrium coherent vortex states and subharmonic giant Shapiro steps in Josephson junction arrays  

E-Print Network [OSTI]

This is a review of recent work on the dynamic response of Josephson junction arrays driven by dc and ac currents. The arrays are modeled by the resistively shunted Josephson junction model, appropriate for proximity effect junctions, including self-induced magnetic fields as well as disorder. The relevance of the self-induced fields is measured as a function of a parameter $\\kappa=\\lambda_L/a$, with $\\lambda_L$ the London penetration depth of the arrays, and $a$ the lattice spacing. The transition from Type II ($\\kappa>1$) to Type I ($\\kappa <1$) behavior is studied in detail. We compare the results for models with self, self+nearest-neighbor, and full inductance matrices. In the $\\kappa=\\infty$ limit, we find that when the initial state has at least one vortex-antivortex pair, after a characteristic transient time these vortices unbind and {\\it radiate} other vortices. These radiated vortices settle into a parity-broken, time-periodic, {\\em axisymmetric coherent vortex state} (ACVS), characterized by alternate rows of positive and negative vortices lying along a tilted axis. The ACVS produces subharmonic steps in the current voltage (IV) characteristics, typical of giant Shapiro steps. For finite $\\kappa$ we find that the IV's show subharmonic giant Shapiro steps, even at zero external magnetic field. We find that these subharmonic steps are produced by a whole family of coherent vortex oscillating patterns, with their structure changing as a function of $\\kappa$. In general, we find that these patterns are due to a break down of translational invariance produced, for example, by disorder or antisymmetric edge-fields. The zero field case results are in good qualitative agreement with experiments

Daniel Domínguez; Jorge V. José

1994-07-11T23:59:59.000Z

185

Irreversible flow of vortex matter: Polycrystal and amorphous phases Paolo Moretti and M.-Carmen Miguel  

E-Print Network [OSTI]

systems exhibiting this phenomenol- ogy, flux line vortex lattices in type II superconductors rep- resent

Miguel-Lopez, Carmen

186

Potential Flow Model of a Vortex Street Near a Fish-like Body  

E-Print Network [OSTI]

Potential Flow Model of a Vortex Street Near a Fish-like Body Joshua Brulé, University of Maryland to inviscid, irrotational solutions of Navier-Stokes · Vortex potential: "A model of the lateral line of fish for vortex sensing." Ren Z, Mohseni K. 2012 #12;Vortex near a (circular) fish · (Insert your own spherical

Anlage, Steven

187

MHK Technologies/Vortex Induced Vibrations Aquatic Clean Energy VIVACE |  

Open Energy Info (EERE)

Vortex Induced Vibrations Aquatic Clean Energy VIVACE Vortex Induced Vibrations Aquatic Clean Energy VIVACE < MHK Technologies Jump to: navigation, search << Return to the MHK database homepage Vortex Induced Vibrations Aquatic Clean Energy VIVACE.jpg Technology Profile Primary Organization Vortex Hydro Energy LLC Project(s) where this technology is utilized *MHK Projects/Marine Hydrodynamics Laboratory at the University of Michigan Technology Resource Click here Current/Tidal Technology Type Click here Reciprocating Device Technology Readiness Level Click here TRL 4: Proof of Concept Technology Description The VIVACE (Vortex Induced Vibrations Aquatic Clean Energy) device is based on the extensively studied phenomenon of Vortex Induced Vibrations (VIV), which was first observed five-hundred years ago by Leonardo DaVinci in the form of 'Aeolian Tones.' VIV results from vortices forming and shedding on the downstream side of a bluff body in a current. Vortex shedding alternates from one side to the other, thereby creating a vibration or oscillation. The VIV phenomenon is non-linear, which means it can produce useful energy at high efficiency over a wide range of current speeds and directions.This converter is unlike any existing technology, as it does not use turbines, propellers, or dams. VIVACE converts the horizontal hydrokinetic energy of currents into cylinder mechanical energy. The latter is then converted to electricity through electric power generators.

188

Reconnection in orthogonally interacting vortex tubes: Direct numerical simulations and quantifications  

Science Journals Connector (OSTI)

The three?dimensional time evolution of two orthogonally offset cylindrical vortices of equal strength is simulated by solving the hyperviscosity?regularized incompressible Navier–Stokes equations. A Fourier pseudospectral method with a time?split integration scheme is used for the solution. Four runs with different Reynolds numbers ranging between 690–2100 are performed each with a resolution of 963 collocation points. The sequence of important physical processes and the evolution of local and global quantities such as vorticity velocity and mean?square strain rate are presented. It is found that the growth rate of the maximum vorticity is at most exponential. The Reynolds number dependence of the time scale of reconnection the vorticity growth rate and the time at which the maximum vorticity is attained are examined and differences between the present results and Saffman’s essentially two?dimensional model predictions are encountered and elucidated. The distributions of the eigenvalues ? ? ? and the corresponding eigenvectors s ? s ? s ? of the rate of strain tensor S i j are calculated at different times. It is found that as the mean?square strain rate ? increases during the evolution s ? and the vorticity vector ? are perfectly aligned and ?>0 in high ? regions. Strong temporal spatial and Reynolds number dependence of the strain fields is also seen. Evidence is presented that during reconnection the vorticity growth in newly forming bridges takes place in the vicinity of the upper stagnation line segment of the vortex dipole due to the nature of the vortex stretching term. Also examined is the initial finger formation and it is found that the initial nonuniform axial stretching and the displacement of the vortex cores due to a lift force play an important role in this process.

O. N. Boratav; R. B. Pelz; N. J. Zabusky

1992-01-01T23:59:59.000Z

189

Integrated multi vector vortex beam generator  

E-Print Network [OSTI]

A novel method to generate and manipulate vector vortex beams in an integrated, ring resonator based geometry is proposed. We show numerically that a ring resonator, with an appropriate grating, addressed by a vertically displaced access waveguide emits a complex optical field. The emitted beam possesses a specific polarization topology, and consequently a transverse intensity profile and orbital angular momentum. We propose a combination of several concentric ring resonators, addressed with different bus guides, to generate arbitrary orbital angular momentum qudit states, which could potentially be used for classical and quantum communications. Finally, we demonstrate numerically that this device works as an orbital angular momentum sorter with an average cross-talk of -10 dB between different orbital angular momentum channels.

Sebastian A. Schulz; Taras Machula; Ebrahim Karimi; Robert W. Boyd

2013-03-19T23:59:59.000Z

190

A study on passive methods of vortex induced vibrations suppression  

E-Print Network [OSTI]

A number of engineering systems, including those found in offshore operations, are often affected by vortex-induced vibrations (VIV). This phenomenon is caused by the interaction between a structure and shed vortices which ...

Galvao, Richardo A

2008-01-01T23:59:59.000Z

191

Experimental demonstration of vortex pancake in high temperature superconductor  

Science Journals Connector (OSTI)

In order to demonstrate the existence of the vortex pancake in high temperature superconductor experimentally, a configuration in which the current...E-j relation obtained with this electrodes spatial configurati...

Wei-xian Wang; Yu-heng Zhang

2006-09-01T23:59:59.000Z

192

MHK Technologies/SeaUrchin Vortex Reaction Turbine | Open Energy  

Open Energy Info (EERE)

SeaUrchin Vortex Reaction Turbine SeaUrchin Vortex Reaction Turbine < MHK Technologies Jump to: navigation, search << Return to the MHK database homepage SeaUrchin Vortex Reaction Turbine.jpg Technology Profile Primary Organization Elemental Energy Technologies Limited ABN 46 128 491 903 Technology Resource Click here Current Technology Type Click here Axial Flow Turbine Technology Readiness Level Click here TRL 4 Proof of Concept Technology Description A revolutionary vortex reaction turbine branded the SeaUrchin an advanced third generation marine turbine technology capable of delivering inexpensive small to large scale baseload or predictable electricity by harnessing the kinetic energy of free flowing ocean currents tides and rivers Technology Dimensions Device Testing Date Submitted 55:15.2

193

Axisymmetric-coherent-vortex states in current-driven Josephson-junction arrays  

SciTech Connect (OSTI)

We present results from an extensive analysis of the dynamic response of Josephson-junction arrays driven by external currents of the form [ital I]=[ital I][sub dc]+[ital I][sub ac]sin(2[pi][nu][ital t]). The dynamics is given by the resistively shunted Josephson-junction model with Johnson noise. We find a stationary [ital axisymmetric][minus][ital coherent][minus][ital vortex] [ital state] (ACVS) away from equilibrium and above a minimum lattice size ([similar to]20[times]20) whenever the initial state has at least one antivortex and a vortex. The ACVS is characterized by tilted rows of oscillating positive and negative vortices, produced by the combined effect of the driving current plus the collective coupling of the nonlinear Josephson oscillators. The ACVS is manifested in the current-voltage characteristics as giant half-integer Shapiro steps, leading to period-two resonances in the spectral function. The stability and properties of the ACVS are studied as a function of frequency, temperature, disorder, edge magnetic fields, and lattice sizes. It is found that the ACVS is a very robust two-dimensional dynamical state that is produced under very diverse circumstances. A connection between the ACVS and half-integer steps seen in proximity effect arrays in zero field is also discussed.

Dominguez, D.; Jose, J.V. (Physics Department, Northeastern University, Boston, Massachusetts 02115 (United States))

1993-11-01T23:59:59.000Z

194

Ultra-Low NOx Advanced Vortex Combustor  

SciTech Connect (OSTI)

An ultra lean-premixed Advanced Vortex Combustor (AVC) has been developed and tested. The natural gas fueled AVC was tested at the U.S. Department of Energy’s National Energy Technology Laboratory (USDOE NETL) test facility in Morgantown (WV). All testing was performed at elevated pressures and inlet temperatures and at lean fuel-air ratios representative of industrial gas turbines. The improved AVC design exhibited simultaneous NOx/CO/UHC emissions of 4/4/0 ppmv (all emissions are at 15% O2 dry). The design also achieved less than 3 ppmv NOx with combustion efficiencies in excess of 99.5%. The design demonstrated tremendous acoustic dynamic stability over a wide range of operating conditions which potentially makes this approach significantly more attractive than other lean premixed combustion approaches. In addition, a pressure drop of 1.75% was measured which is significantly lower than conventional gas turbine combustors. Potentially, this lower pressure drop characteristic of the AVC concept translates into overall gas turbine cycle efficiency improvements of up to one full percentage point. The relatively high velocities and low pressure drops achievable with this technology make the AVC approach an attractive alternative for syngas fuel applications.

Edmonds, R.G. (Ramgen Power Systems, Inc., Bellevue, WA); Steele, R.C. (Ramgen Power Systems, Inc., Bellevue, WA); Williams, J.T. (Ramgen Power Systems, Inc., Bellevue, WA); Straub, D.L.; Casleton, K.H.; Bining, Avtar (California Energy Commission, Sacramento, CA)

2006-05-01T23:59:59.000Z

195

ULTRA-LOW NOX ADVANCED VORTEX COMBUSTOR  

SciTech Connect (OSTI)

An ultra lean-premixed Advanced Vortex Combustor (AVC) has been developed and tested. The natural gas fueled AVC was tested at the U.S. Department of Energy’s National Energy Technology Laboratory (USDOE NETL) test facility in Morgantown (WV). All testing was performed at elevated pressures and inlet temperatures and at lean fuel-air ratios representative of industrial gas turbines. The improved AVC design exhibited simultaneous NOx/CO/UHC emissions of 4/4/0 ppmv (all emissions are at 15% O2 dry). The design also achieved less than 3 ppmv NOx with combustion efficiencies in excess of 99.5%. The design demonstrated tremendous acoustic dynamic stability over a wide range of operating conditions which potentially makes this approach significantly more attractive than other lean premixed combustion approaches. In addition, a pressure drop of 1.75% was measured which is significantly lower than conventional gas turbine combustors. Potentially, this lower pressure drop characteristic of the AVC concept translates into overall gas turbine cycle efficiency improvements of up to one full percentage point. The relatively high velocities and low pressure drops achievable with this technology make the AVC approach an attractive alternative for syngas fuel applications.

Ryan G. Edmonds; Robert C. Steele; Joseph T. Williams; Douglas L. Straub; Kent H. Casleton; Avtar Bining

2006-05-01T23:59:59.000Z

196

Effective world-sheet theory of color magnetic flux tubes in dense QCD  

SciTech Connect (OSTI)

Color magnetic flux tubes appear in the color-flavor locked phase of high density QCD, which exhibits color superconductivity as well as superfluidity. They are non-Abelian superfluid vortices and are accompanied by orientational zero modes in the internal space associated with the color-flavor locked symmetry spontaneously broken in the presence of the vortex. We show that those zero modes are localized around the vortex in spite of the logarithmic divergence of its tension and derive the low-energy effective theory of them on the world sheet of the vortex string.

Eto, Minoru [Theoretical Physics Laboratory, RIKEN, Saitama 351-0198 (Japan); Nakano, Eiji [Extreme Matter Institute, GSI, Planckstrasse 1, D-64291 Darmstadt (Germany); Nitta, Muneto [Department of Physics, and Research and Education Center for Natural Sciences, Keio University, 4-1-1 Hiyoshi, Yokohama, Kanagawa 223-8521 (Japan)

2009-12-15T23:59:59.000Z

197

Color Magnetic Flux Tubes in Dense QCD. II: Effective World-Sheet Theory  

E-Print Network [OSTI]

Color magnetic flux tubes appear in the color-flavor locked phase of high density QCD, which exhibits color superconductivity as well as superfluidity. They are non-Abelian superfluid vortices and are accompanied by orientational zero modes in the internal space associated with the color-flavor locked symmetry spontaneously broken in the presence of the vortex. We show that those zero modes are localized around the vortex in spite of the logarithmic divergence of its tension, and derive the low-energy effective theory of them on the world-sheet of the vortex-string.

Minoru Eto; Eiji Nakano; Muneto Nitta

2009-08-31T23:59:59.000Z

198

Color Magnetic Flux Tubes in Dense QCD. II: Effective World-Sheet Theory  

E-Print Network [OSTI]

Color magnetic flux tubes appear in the color-flavor locked phase of high density QCD, which exhibits color superconductivity as well as superfluidity. They are non-Abelian superfluid vortices and are accompanied by orientational zero modes in the internal space associated with the color-flavor locked symmetry spontaneously broken in the presence of the vortex. We show that those zero modes are localized around the vortex in spite of the logarithmic divergence of its tension, and derive the low-energy effective theory of them on the world-sheet of the vortex-string.

Eto, Minoru; Nitta, Muneto

2009-01-01T23:59:59.000Z

199

Wave–vortex interactions in the nonlinear Schrödinger equation  

SciTech Connect (OSTI)

This is a theoretical study of wave–vortex interaction effects in the two-dimensional nonlinear Schrödinger equation, which is a useful conceptual model for the limiting dynamics of superfluid quantum condensates at zero temperature. The particular wave–vortex interaction effects are associated with the scattering and refraction of small-scale linear waves by the straining flows induced by quantized point vortices and, crucially, with the concomitant nonlinear back-reaction, the remote recoil, that these scattered waves exert on the vortices. Our detailed model is a narrow, slowly varying wavetrain of small-amplitude waves refracted by one or two vortices. Weak interactions are studied using a suitable perturbation method in which the nonlinear recoil force on the vortex then arises at second order in wave amplitude, and is computed in terms of a Magnus-type force expression for both finite and infinite wavetrains. In the case of an infinite wavetrain, an explicit asymptotic formula for the scattering angle is also derived and cross-checked against numerical ray tracing. Finally, under suitable conditions a wavetrain can be so strongly refracted that it collapses all the way onto a zero-size point vortex. This is a strong wave–vortex interaction by definition. The conditions for such a collapse are derived and the validity of ray tracing theory during the singular collapse is investigated.

Guo, Yuan, E-mail: yuanguo@cims.nyu.edu; Bühler, Oliver [Courant Institute of Mathematical Sciences, New York University, New York, New York 10012 (United States)] [Courant Institute of Mathematical Sciences, New York University, New York, New York 10012 (United States)

2014-02-15T23:59:59.000Z

200

Experimental Investigations of Vortex Induced Vibration of A Flat Plate in Pitch Oscillation  

E-Print Network [OSTI]

A bluff structure placed in a flowing fluid, may be subjected to vortex-induced vibrations (VIV). For a flat plate with only rotational degree of freedom, the VIV is rotational oscillation. Based on the experimental investigation, vortex...

Yang, Yi

2012-02-14T23:59:59.000Z

Note: This page contains sample records for the topic "magnetic vortex core" 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

Generation and Propagation of Inertia Gravity Waves from Vortex Dipoles and Jets Shuguang Wang  

E-Print Network [OSTI]

Generation and Propagation of Inertia Gravity Waves from Vortex Dipoles and Jets Shuguang Wang generation and propagation from jets within idealized vortex dipoles using a nonhydrostatic mesoscale model, moist convection, fronts, upper level jets, geostrophic adjustment and spontaneous generation (Fritts

202

A constant shear stress core flow model of the bidirectional vortex  

Science Journals Connector (OSTI)

...Chiaverini, M. J., Sauer, J. A. Knuth, W. H. 2004 Numerical code development for simulating gel propellant combustion processes. JANNAF Paper (unclassified). Ogawa, A 1984Estimation of the collection efficiencies of the three types of...

2009-01-01T23:59:59.000Z

203

Core Drilling Demonstration  

Broader source: Energy.gov [DOE]

Tank Farms workers demonstrate core drilling capabilities for Hanford single-shell tanks. Core drilling is used to determine the current condition of each tank to assist in the overall assessment...

204

Superconducting Magnet Division  

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

3 - 6/13/06 3 - 6/13/06 Superconducting Magnet Division S&T Committee Program Review June 22-23, 2006 Conference Room A, Bldg. 725, BNL DRAFT AGENDA Thursday, June 22 0830 Executive Session to address the charge S. Aronson (25 min) 0855 Welcome S. Aronson (5 min) 0900 Superconducting Magnet Division Status & M. Harrison (45 + 15 min) Issues - mission statement, core competencies, themes, program, problems, etc. 1000 Themes - Nb3Sn, HTS, Direct wind, Accelerator integration, P. Wanderer (20 + 10 min) rapid cycling Core Competencies 1030 Superconducting Materials A. Ghosh (20 + 5 min) 1055 Break 1110 Magnetic Design R. Gupta (20 + 5 min) 1135 Magnet Construction M. Anerella (20 + 5 min) 1200 Magnet Testing G. Ganetis (20 + 5 min)

205

Mutual Chern-Simons gauge theory of spontaneous vortex phase  

Science Journals Connector (OSTI)

We apply the mutual Chern-Simons effective theory [Kou, Qi, and Weng, Phys. Rev. B 71, 235102 (2005)] of the doped Mott insulator to the study of the so-called spontaneous vortex phase in the low-temperature pseudogap region, which is characterized by strong unconventional superconducting fluctuations. An effective description for the spontaneous vortex phase is derived from the general mutual Chern-Simons Lagrangian, based on which the physical properties including the diamagnetism, spin paramagnetism, magnetoresistance, and the Nernst coefficient, have been quantitatively calculated. The phase boundaries of the spontaneous vortex phase, which sits between the onset temperature Tv and the superconducting transition temperature Tc, are also determined within the same framework. The results are consistent with the experimental measurements of the cuprates.

Xiao-Liang Qi and Zheng-Yu Weng

2007-09-07T23:59:59.000Z

206

The effect of surface tension on the Moore singularity of vortex sheet dynamics  

E-Print Network [OSTI]

The effect of surface tension on the Moore singularity of vortex sheet dynamics F. de la Hoz , M's singularities by surface tension in the evolution of vortex sheets and its dependence on Weber number (which is inversely proportional to surface tension coefficient). The curvature of the vortex sheet, instead

Fontelos, Marco

207

Traveling Waves from the Arclength Parameterization: Vortex Sheets with Surface Tension  

E-Print Network [OSTI]

Traveling Waves from the Arclength Parameterization: Vortex Sheets with Surface Tension Benjamin for the vortex sheet with surface tension. We use the angle- arclength description of the interface rather than prove that there exist traveling vortex sheets with surface tension bifurcating from equilibrium. We

Wright, J. Douglas

208

CALTECH ASCI TECHNICAL REPORT 129 On Velocity Structure Functions and the Spherical Vortex Model for  

E-Print Network [OSTI]

the stretched-spiral vortex has been suc- cessfully applied to the calculation of the energy spectrum,6 and some for larger scales is perhaps questionable. Most quantitative vortex-based models have utilized tube and sheetCALTECH ASCI TECHNICAL REPORT 129 On Velocity Structure Functions and the Spherical Vortex Model

Barr, Al

209

Vortex Formation in a Plasma Interacting with Neutral Flow  

SciTech Connect (OSTI)

Recently, it has been observed that there exists a class of vortices which rotates in the opposite direction to ExB drift (referred to as anti-ExB vortex). This result suggests that a predominant force other than electric field is acting on ions. It is found that momentum transport and resultant force generation through the interaction between ions and neutral flow play an essential role on anti-ExB vortex formation. The existence of inward neutral flow, which drives the ions in the anti-ExB direction, has been confirmed using a newly-developed high-resolution laser induced fluorescence (LIF) spectroscopy system.

Tanaka, M. Y.; Ogiwara, K.; Etoh, S. [Department of High Energy Engineering Science, Kyushu University, Kasuga-koen 6-1, Kasuga 816-8580 (Japan); Aramaki, M. [Department of Electrical Engineering, Nagoya University, Chikusa, Nagoya 464-8603 (Japan); Yoshimura, S. [National Institute for Fusion Science, Oroshi 322-6, Toki 509-5292 (Japan); Varanjes, J. [Center for Plasma Astrophysics, Celestijnenlaan 200 B 3001 Leuven (Belgium)

2008-10-15T23:59:59.000Z

210

Laboratory Analysis of Vortex Dynamics For Shallow Tidal Inlets  

E-Print Network [OSTI]

LABORATORY ANALYSIS OF VORTEX DYNAMICS FOR SHALLOW TIDAL INLETS A Thesis by KERRI ANN WHILDEN Submitted to the O ce of Graduate Studies of Texas A&M University in partial ful llment of the requirements for the degree of MASTER OF SCIENCE August 2009... Major Subject: Ocean Engineering LABORATORY ANALYSIS OF VORTEX DYNAMICS FOR SHALLOW TIDAL INLETS A Thesis by KERRI ANN WHILDEN Submitted to the O ce of Graduate Studies of Texas A&M University in partial ful llment of the requirements for the degree...

Whilden, Kerri Ann

2010-10-12T23:59:59.000Z

211

Revival of Classical Vortex Generators Now for Transition Delay  

Science Journals Connector (OSTI)

Classical vortex generators, known for their efficiency in delaying or even inhibiting boundary layer separation, are here shown to be coveted devices for transition to turbulence delay. The present devices are miniature with respect to classical vortex generators but are tremendously powerful in modulating the laminar boundary layer in the direction orthogonal to the base flow and parallel to the surface. The modulation generates an additional term in the perturbation energy equation, which counteracts the wall-normal production term and, hence, stabilizes the flow. Our experimental results show that these devices are really effective in delaying transition, but we also reveal their Achilles’ heel.

Shahab Shahinfar; Sohrab S. Sattarzadeh; Jens H. M. Fransson; Alessandro Talamelli

2012-08-16T23:59:59.000Z

212

Vortex Diode Analysis and Testing for Fluoride Salt-Cooled High-Temperature Reactors  

SciTech Connect (OSTI)

Fluidic diodes are presently being considered for use in several fluoride salt-cooled high-temperature reactor designs. A fluidic diode is a passive device that acts as a leaky check valve. These devices are installed in emergency heat removal systems that are designed to passively remove reactor decay heat using natural circulation. The direct reactor auxiliary cooling system (DRACS) uses DRACS salt-to-salt heat exchangers (DHXs) that operate in a path parallel to the core flow. Because of this geometry, under normal operating conditions some flow bypasses the core and flows through the DHX. A flow diode, operating in reverse direction, is-used to minimize this flow when the primary coolant pumps are in operation, while allowing forward flow through the DHX under natural circulation conditions. The DRACSs reject the core decay heat to the environment under loss-of-flow accident conditions and as such are a reactor safety feature. Fluidic diodes have not previously been used in an operating reactor system, and therefore their characteristics must be quantified to ensure successful operation. This report parametrically examines multiple design parameters of a vortex-type fluidic diode to determine the size of diode needed to reject a particular amount of decay heat. Additional calculations were performed to size a scaled diode that could be tested in the Oak Ridge National Laboratory Liquid Salt Flow Loop. These parametric studies have shown that a 152.4 mm diode could be used as a test article in that facility. A design for this diode is developed, and changes to the loop that will be necessary to test the diode are discussed. Initial testing of a scaled flow diode has been carried out in a water loop. The 150 mm diode design discussed above was modified to improve performance, and the final design tested was a 171.45 mm diameter vortex diode. The results of this testing indicate that diodicities of about 20 can be obtained for diodes of this size. Experimental results show similar trends as the computational fluid dynamics (CFD) results presented in this report; however, some differences exist that will need to be assessed in future studies. The results of this testing will be used to improve the diode design to be tested in the liquid salt loop system.

Yoder Jr, Graydon L [ORNL; Elkassabgi, Yousri M. [Texas A& M University, Kingsville; De Leon, Gerardo I. [Texas A& M University, Kingsville; Fetterly, Caitlin N. [Texas A& M University, Kingsville; Ramos, Jorge A. [Texas A& M University, Kingsville; Cunningham, Richard Burns [University of Tennessee, Knoxville (UTK)

2012-02-01T23:59:59.000Z

213

HYDRATE CORE DRILLING TESTS  

SciTech Connect (OSTI)

The ''Methane Hydrate Production from Alaskan Permafrost'' project is a three-year endeavor being conducted by Maurer Technology Inc. (MTI), Noble, and Anadarko Petroleum, in partnership with the U.S. DOE National Energy Technology Laboratory (NETL). The project's goal is to build on previous and ongoing R&D in the area of onshore hydrate deposition. The project team plans to design and implement a program to safely and economically drill, core and produce gas from arctic hydrates. The current work scope includes drilling and coring one well on Anadarko leases in FY 2003 during the winter drilling season. A specially built on-site core analysis laboratory will be used to determine some of the physical characteristics of the hydrates and surrounding rock. Prior to going to the field, the project team designed and conducted a controlled series of coring tests for simulating coring of hydrate formations. A variety of equipment and procedures were tested and modified to develop a practical solution for this special application. This Topical Report summarizes these coring tests. A special facility was designed and installed at MTI's Drilling Research Center (DRC) in Houston and used to conduct coring tests. Equipment and procedures were tested by cutting cores from frozen mixtures of sand and water supported by casing and designed to simulate hydrate formations. Tests were conducted with chilled drilling fluids. Tests showed that frozen core can be washed out and reduced in size by the action of the drilling fluid. Washing of the core by the drilling fluid caused a reduction in core diameter, making core recovery very difficult (if not impossible). One successful solution was to drill the last 6 inches of core dry (without fluid circulation). These tests demonstrated that it will be difficult to capture core when drilling in permafrost or hydrates without implementing certain safeguards. Among the coring tests was a simulated hydrate formation comprised of coarse, large-grain sand in ice. Results with this core showed that the viscosity of the drilling fluid must also be carefully controlled. When coarse sand was being cored, the core barrel became stuck because the drilling fluid was not viscous enough to completely remove the large grains of sand. These tests were very valuable to the project by showing the difficulties in coring permafrost or hydrates in a laboratory environment (as opposed to a field environment where drilling costs are much higher and the potential loss of equipment greater). Among the conclusions reached from these simulated hydrate coring tests are the following: Frozen hydrate core samples can be recovered successfully; A spring-finger core catcher works best for catching hydrate cores; Drilling fluid can erode the core and reduces its diameter, making it more difficult to capture the core; Mud must be designed with proper viscosity to lift larger cuttings; and The bottom 6 inches of core may need to be drilled dry to capture the core successfully.

John H. Cohen; Thomas E. Williams; Ali G. Kadaster; Bill V. Liddell

2002-11-01T23:59:59.000Z

214

Vortex trimer in three-component Bose-Einstein condensates  

E-Print Network [OSTI]

Vortex trimer is predicted in three-component Bose-Einstein condensates with internal coherent couplings. The molecule is made by three constituent vortices which are bounded by domain walls of the relative phases. We show that the shape and the size of the molecule can be controlled by changing the internal coherent couplings.

Minoru Eto; Muneto Nitta

2012-01-01T23:59:59.000Z

215

High-Resolution Simulations of Parallel BladeVortex Interactions  

E-Print Network [OSTI]

= perturbation pressure coefficient, p ps= 1 2 1U2 1 c = rotor blade chord p = instantaneous airfoil surface­vortex interaction computations Introduction A MAJOR source of rotorcraft noise is generated by the rotor blades on the rotor blades. BVI noise is especially important because it is known to propagate out

Alonso, Juan J.

216

WAVE-VORTEX INTERACTIONS IN THE ATMOSPHERE, AND CLIMATE  

E-Print Network [OSTI]

parcel dynamics, linear modes, balan- ced models, gravity waves, weather and climate prediction Introduction Numerical weather and climate prediction is complicated because only the flow scales larger thanWAVE-VORTEX INTERACTIONS IN THE ATMOSPHERE, AND CLIMATE PREDICTION Onno Bokhove Numerical Analysis

Vellekoop, Michel

217

Modified Black Hole with Polar Jet and Vortex  

E-Print Network [OSTI]

There are many models relating an accretion disk of Black Hole to jet outflow. The herein heuristic model describes the continuation of an external accretion disk to an internal accretion disk for less than Black Hole horizon, and subsequent polar jet outflow along polar axis out of polar vortex wherein the event horizon is no longer descriptive.

T. Tmmalm

2001-12-06T23:59:59.000Z

218

Anisotropic superconductivity and vortex dynamics in magnetially coupled F/S and F/S/F hybrids.  

SciTech Connect (OSTI)

Magnetically coupled superconductor-ferromagnet hybrids offer advanced routes for nanoscale control of superconductivity. Magnetotransport characteristics and scanning tunneling microscopy images of vortex structures in superconductor-ferromagnet hybrids reveal rich superconducting phase diagrams. Focusing on a particular combination of a ferromagnet with a well-ordered periodic magnetic domain structure with alternating out-of-plane component of magnetization, and a small coherence length superconductor, we find directed nucleation of superconductivity above the domain wall boundaries. We show that near the superconductor-normal state phase boundary the superconductivity is localized in narrow mesoscopic channels. In order to explore the Abrikosov flux line ordering in F/S hybrids, we use a combination of scanning tunneling microscopy and Ginzburg-Landau simulations. The magnetic stripe domain structure induces periodic local magnetic induction in the superconductor, creating a series of pinning-anti-pinning channels for externally added magnetic flux quanta. Such laterally confined Abrikosov vortices form quasi-1D arrays (chains). The transitions between multichain states occur through propagation of kinks at the intermediate fields. At high fields we show that the system becomes nonlinear due to a change in both the number of vortices and the confining potential. In F/S/F hybrids we demonstrate the evolution of the anisotropic conductivity in the superconductor that is magnetically coupled with two adjacent ferromagnetic layers. Stripe magnetic domain structures in both F-layers are aligned under each other, resulting in a directional superconducting order parameter in the superconducting layer. The conductance anisotropy strongly depends on the period of the magnetic domains and the strength of the local magnetization. The anisotropic conductivity of up to three orders of magnitude can be achieved with a spatial critical temperature modulation of 5% of T{sub c}. Induced anisotropic properties in the F/S and F/S/F hybrids have a potential for future application in switching and nonvolatile memory elements operating at low temperatures.

Karapetrov, G.; Belkin, A.; Iavarone, M.; Fedor, J.; Novosad, V.; Milosevic, M. V.; Peeters, F. M. (Materials Science Division); (Illinois Inst. of Tech.); (Temple Univ.); (Slovak Academy of Sciences); (Univ. Antwerpen)

2011-01-01T23:59:59.000Z

219

RADIATION MAGNETOHYDRODYNAMIC SIMULATIONS OF PROTOSTELLAR COLLAPSE: PROTOSTELLAR CORE FORMATION  

SciTech Connect (OSTI)

We report the first three-dimensional radiation magnetohydrodynamic (RMHD) simulations of protostellar collapse with and without Ohmic dissipation. We take into account many physical processes required to study star formation processes, including a realistic equation of state. We follow the evolution from molecular cloud cores until protostellar cores are formed with sufficiently high resolutions without introducing a sink particle. The physical processes involved in the simulations and adopted numerical methods are described in detail. We can calculate only about one year after the formation of the protostellar cores with our direct three-dimensional RMHD simulations because of the extremely short timescale in the deep interior of the formed protostellar cores, but successfully describe the early phase of star formation processes. The thermal evolution and the structure of the first and second (protostellar) cores are consistent with previous one-dimensional simulations using full radiation transfer, but differ considerably from preceding multi-dimensional studies with the barotropic approximation. The protostellar cores evolve virtually spherically symmetric in the ideal MHD models because of efficient angular momentum transport by magnetic fields, but Ohmic dissipation enables the formation of the circumstellar disks in the vicinity of the protostellar cores as in previous MHD studies with the barotropic approximation. The formed disks are still small (less than 0.35 AU) because we simulate only the earliest evolution. We also confirm that two different types of outflows are naturally launched by magnetic fields from the first cores and protostellar cores in the resistive MHD models.

Tomida, Kengo [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States)] [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Tomisaka, Kohji [Department of Astronomical Science, The Graduate University for Advanced Studies (SOKENDAI), Osawa, Mitaka, Tokyo 181-8588 (Japan)] [Department of Astronomical Science, The Graduate University for Advanced Studies (SOKENDAI), Osawa, Mitaka, Tokyo 181-8588 (Japan); Matsumoto, Tomoaki [Faculty of Humanity and Environment, Hosei University, Fujimi, Chiyoda-ku, Tokyo 102-8160 (Japan)] [Faculty of Humanity and Environment, Hosei University, Fujimi, Chiyoda-ku, Tokyo 102-8160 (Japan); Hori, Yasunori; Saigo, Kazuya [National Astronomical Observatory of Japan, Osawa, Mitaka, Tokyo 181-8588 (Japan)] [National Astronomical Observatory of Japan, Osawa, Mitaka, Tokyo 181-8588 (Japan); Okuzumi, Satoshi [Department of Physics, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602 (Japan)] [Department of Physics, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602 (Japan); Machida, Masahiro N., E-mail: tomida@astro.princeton.edu, E-mail: tomisaka@th.nao.ac.jp, E-mail: yasunori.hori@nao.ac.jp, E-mail: saigo.kazuya@nao.ac.jp, E-mail: matsu@hosei.ac.jp, E-mail: okuzumi@nagoya-u.jp, E-mail: machida.masahiro.018@m.kyushu-u.ac.jp [Department of Earth and Planetary Sciences, Faculty of Sciences, Kyushu University, Hakozaki, Higashi-ku, Fukuoka 812-8581 (Japan)

2013-01-20T23:59:59.000Z

220

Engineering Nanocolumnar Defect Configurations for Optimized Vortex Pinning in High Temperature Superconducting Nanocomposite Wires  

SciTech Connect (OSTI)

High temperature superconducting (HTS), coated conductor wires based on nanocomposite films containing self-assembled, insulating BaZrO3 (BZO) nanocolumnar defects have previously been reported to exhibit enhanced vortex pinning. Here, we report on microstructural design via control of BZO nanocolumns density in YBa2Cu3O7- (YBCO)+BZO nancomposite films to achieve the highest critical current density, Jc(H, ,T). X-ray diffraction and microstructural examination shows increasing number density of epitaxial BZO nanocolumns in the highly cube-textured YBCO matrix with increasing nominal BZO additions. Transport property measurement reveals that an increase in BZO content upto 4 vol% is required to sustain the highest pinning and Jc performance as the magnetic field increases. By growing thicker, single-layer nanocomposite films (~4 m) with controlled density of BZO columnar defects, the critical current (Ic) of ~1000 A/cm at 77 K, self-field and the minimum Ic of 455 A/cm at 65 K and 3 T for all magnetic field orientations were obtained. This is the highest Ic reported to date for films on metallic templates which are the basis for the 2nd generation, coated conductor-based HTS wires.

Wee, Sung Hun [ORNL; Zuev, Yuri L [ORNL; Cantoni, Claudia [ORNL; Goyal, Amit [ORNL; Ahuja, Raj [Waukesha Electric Systems Inc.; Abiade, J. [North Carolina A& T State University

2013-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "magnetic vortex core" 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

Higher Derivative Corrections to Non-Abelian Vortex Effective Theory  

E-Print Network [OSTI]

We give a systematic method to calculate higher derivative corrections to low-energy effective theories of solitons, which are in general non-linear sigma models on the moduli spaces of the solitons. By applying it to the effective theory of a single BPS non-Abelian vortex in U(N) gauge theory with N fundamental Higgs fields, we obtain four derivative corrections to the effective sigma model on the moduli space C \\times CP^{N-1}. We compare them with the Nambu-Goto action and the Faddeev-Skyrme model. We also show that Yang-Mills instantons/monopoles trapped inside a non-Abelian vortex membrane/string are not modified in the presence of higher derivative terms.

Minoru Eto; Toshiaki Fujimori; Muneto Nitta; Keisuke Ohashi; Norisuke Sakai

2012-04-03T23:59:59.000Z

222

Precession of a single vortex line in superfluid B3  

Science Journals Connector (OSTI)

This paper reports the discovery of a new vortex phenomenon in superfluid B3. A single filament of quantized vortex line precesses as a solid body around a wire extending along the axis of a cylinder. The precession frequency equals the angular velocity of the apparatus at which the presence of a single quantum of circulation minimizes the system’s free energy. The period of precession is related to the circulation quantum and the dimensions of the apparatus. Thus a measurement of the precession period is an accurate determination of the quantum unit. We find ?=(1.020±0.03)h/2m3, where m3 is the mass of the He3 atom.

R. J. Zieve; Yu. Mukharsky; J. D. Close; J. C. Davis; R. E. Packard

1992-03-02T23:59:59.000Z

223

MHK Technologies/Vortex Oscillation | Open Energy Information  

Open Energy Info (EERE)

Oscillation Oscillation < MHK Technologies Jump to: navigation, search << Return to the MHK database homepage Vortex Oscillation.jpg Technology Profile Primary Organization Vortex Oscillation Technology Ltd Technology Resource Click here Current Technology Type Click here Attenuator Technology Readiness Level Click here TRL 1 3 Discovery Concept Def Early Stage Dev Design Engineering Technology Description If cylinder or another body is fixed on a moving bonding this force can set the body or its separate parts into oscillation e g elastic slat If the system of mechanical energy output is organized correctly this device can be considered as generator Technology Dimensions Device Testing Date Submitted 08:12.7 << Return to the MHK database homepage Retrieved from

224

-The Core of CS -Curricula  

E-Print Network [OSTI]

- Advanced Courses #12;The Core of CS Curricula #12;CS Body of Knowledge Area > Unit > Topic Core vs elective#12;ACM vs U S I #12;- The Core of CS - Curricula - Introductory Courses - Intermediate Courses Introductory Intermediate Advanced Core Elective Units #12;Courses Introductory Intermediate Advanced Core

Hauswirth, Matthias

225

Vortex energy and 360 Neel walls in thinfilm  

E-Print Network [OSTI]

.Ignat@math.u-psud.fr) Courant Institute, New York University, New York, NY 10012, USA (e-mail: knuepfer@cims.nyu.edu) 1 #12Vortex energy and 360 ­N´eel walls in thin­film micromagnetics Radu Ignat , Hans Kn¨upfer October-section. The model is based on the following energy functional: E2d (m) = Z B2 |m|2 dx + | ln | 2 Z R2 ||-1

226

Coherence Current, Coherence Vortex, and the Conservation Law of Coherence  

Science Journals Connector (OSTI)

Introducing scalar and vector densities for a mutual coherence function, we present a new conservation law for optical coherence of scalar wave fields in the form of a continuity equation. This coherence conservation law provides new insights into topological phenomena for the complex coherence function. Some properties related to the newly introduced coherence vector density, such as a circulating coherence current associated with a coherence vortex, are investigated both theoretically and experimentally for the first time.

Wei Wang and Mitsuo Takeda

2006-06-08T23:59:59.000Z

227

Core shroud corner joints  

DOE Patents [OSTI]

A core shroud is provided, which includes a number of planar members, a number of unitary corners, and a number of subassemblies each comprising a combination of the planar members and the unitary corners. Each unitary corner comprises a unitary extrusion including a first planar portion and a second planar portion disposed perpendicularly with respect to the first planar portion. At least one of the subassemblies comprises a plurality of the unitary corners disposed side-by-side in an alternating opposing relationship. A plurality of the subassemblies can be combined to form a quarter perimeter segment of the core shroud. Four quarter perimeter segments join together to form the core shroud.

Gilmore, Charles B.; Forsyth, David R.

2013-09-10T23:59:59.000Z

228

Transient vortex events in the initial value problem for turbulence  

E-Print Network [OSTI]

A vorticity surge event that could be a paradigm for a wide class of bursting events in turbulence is studied to examine how the energy cascade is established and how this event could serve as a new test of LES turbulence models. This vorticity surge event is tied to the formation of the energy cascade in a direct numerical simulation by the traditional signatures of a turbulent energy cascade such as spectra approaching -5/3 and strongly Beltramized vortex tubes. A coherent mechanism is suggested by the nearly simultaneous development of a maximum of the peak vorticity $\\|\\omega\\|_\\infty$, growth of the dissipation, the appearance of a helically aligned local vortex configuration and strong, transient oscillations in the helicity wavenumber spectrum. This coherence is also examined for two LES models, a traditional purely dissipative eddy viscosity model and a modern method (LANS$-\\alpha$) that respects the nonlinear transport properties of fluids. Both LES models properly represent the spectral energy and energy dissipation associated with this vorticity surge event. However, only the model that preserves nonlinear fluid transport properties reproduces the helical properties, including Beltrami-like vortex tubes.

Darryl D. Holm; Robert M. Kerr

2001-10-19T23:59:59.000Z

229

Saturable inductor and transformer structures for magnetic pulse compression  

DOE Patents [OSTI]

Saturable inductor and transformer for magnetic compression of an electronic pulse, using a continuous electrical conductor looped several times around a tightly packed core of saturable inductor material.

Birx, Daniel L. (Londonderry, NH); Reginato, Louis L. (Orinda, CA)

1990-01-01T23:59:59.000Z

230

Magnets and Power Supplies  

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

Bibliography Up: APS Storage Ring Parameters Previous: Longitudinal Bibliography Up: APS Storage Ring Parameters Previous: Longitudinal bunch profile and Magnets and Power Supplies Dipole Magnets and Power Supplies Value Dipole Number 80+1 No. of power supplies 1 Magnetic length 3.06 m Core length 3.00 m Bending radius 38.9611 m Power supply limit 500.0 A Field at 7 GeV 0.599 T Dipole trim coils Number 80+1 No. of power supplies 80 Magnetic length 3.06 m Core length 3.00 m Power supply limit 20.0 A Maximum field 0.04 T Horizontal Correction Dipoles Number 317 No. of power supplies 317 Magnetic length 0.160 m Core length 0.07 m Power supply limit 150.0 A Maximum field 0.16 T Max. deflection at 7 GeV 1.1 mrad Vertical Corrector Dipoles Number 317 No. of power supplies 317

231

Coherence Holography and Spatial Frequency Comb for 3-D Coherence Imaging and Coherence Vortex Generation  

Science Journals Connector (OSTI)

The principle and the applications of a recently proposed unconventional holography technique, coherence holography, applied for coherence vortex generation, and a related technique...

Takeda, Mitsuo; Wang, Wei; Duan, Zhihui; Miyamoto, Yoko; Rosen, Joseph

232

Vortex shedding from square plates near a ground plane: an experimental study.  

E-Print Network [OSTI]

??Vortex shedding frequencies were obtained experimentally for square plates near a ground plane in the Texas Tech wind tunnel. These frequencies, in the form of… (more)

Matty, Rosemary Ricohermoso

1979-01-01T23:59:59.000Z

233

Rotational Doppler-effect due to selective excitation of vector-vortex field in optical fiber  

Science Journals Connector (OSTI)

Experimental demonstration of rotational Doppler-effect due to direct and simultaneous excitation of orthogonal elliptically-polarized fundamental and vortex modes in a two-mode...

Inavalli, V V G Krishna; Viswanathan, Nirmal K

2011-01-01T23:59:59.000Z

234

Oxygen to the core  

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

1-01 1-01 For immediate release: 01/10/2013 | NR-13-01-01 Oxygen to the core Anne M Stark, LLNL, (925) 422-9799, stark8@llnl.gov Printer-friendly An artist's conception of Earth's inner and outer core. LIVERMORE, Calif. -- An international collaboration including researchers from Lawrence Livermore National Laboratory has discovered that the Earth's core formed under more oxidizing conditions than previously proposed. Through a series of laser-heated diamond anvil cell experiments at high pressure (350,000 to 700,000 atmospheres of pressure) and temperatures (5,120 to 7,460 degrees Fahrenheit), the team demonstrated that the depletion of siderophile (also known as "iron loving") elements can be produced by core formation under more oxidizing conditions than earlier

235

Core assembly storage structure  

DOE Patents [OSTI]

A structure for the storage of core assemblies from a liquid metal-cooled nuclear reactor. The structure comprises an enclosed housing having a substantially flat horizontal top plate, a bottom plate and substantially vertical wall members extending therebetween. A plurality of thimble members extend downwardly through the top plate. Each thimble member is closed at its bottom end and has an open end adjacent said top plate. Each thimble member has a length and diameter greater than that of the core assembly to be stored therein. The housing is provided with an inlet duct for the admission of cooling air and an exhaust duct for the discharge of air therefrom, such that when hot core assemblies are placed in the thimbles, the heat generated will by convection cause air to flow from the inlet duct around the thimbles and out the exhaust duct maintaining the core assemblies at a safe temperature without the necessity of auxiliary powered cooling equipment.

Jones, Jr., Charles E. (Northridge, CA); Brunings, Jay E. (Chatsworth, CA)

1988-01-01T23:59:59.000Z

236

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

237

residual magnetism  

Science Journals Connector (OSTI)

The magnetization, i.e., the magnetic polarization, that remains in a magnetized material after all attempts to remove the magnetization have been made. Note: An example of residual magnetization is the magnetiza...

2001-01-01T23:59:59.000Z

238

Manifestations of magnetic vortices in equation of state of Yang-Mills plasma  

E-Print Network [OSTI]

The vacuum of Yang-Mills theory contains singular stringlike objects identified with center (magnetic) vortices. Percolation of magnetic vortices is known to be responsible for the color confinement in the low-temperature phase of the theory. In our work we study properties of the vortices at finite temperature using lattice simulations of SU(2) gauge theory. We show that magnetic vortices provide a numerically large contribution to thermodynamic quantities of the gluon plasma in Yang-Mills theory. In particular, we observe that in the deconfinement phase at temperatures T_c energy-momentum tensor. In the confinement phase the vortex contribution is positive. The thermodynamical significance of the magnetic objects allows us to suggest that the quark-gluon plasma may contain a developed network of magnetic flux tubes. The existence of the vortex network may lead to observable effects in the quark-gluon plasma because the chromomagnetic field of the vortices should scatter and drag quarks.

M. N. Chernodub; Atsushi Nakamura; V. I. Zakharov

2008-07-31T23:59:59.000Z

239

Manifestations of magnetic vortices in equation of state of Yang-Mills plasma  

E-Print Network [OSTI]

The vacuum of Yang-Mills theory contains singular stringlike objects identified with center (magnetic) vortices. The percolation of the magnetic vortices is known to be responsible for the color confinement in the low-temperature phase of the theory. In our work we study properties of the vortices at finite temperature using lattice simulations of SU(2) gauge theory. We show that magnetic vortices provide numerically large contribution to thermodynamic quantities of gluon plasma in Yang-Mills theory. In particular, we observe that in the deconfinement phase at temperatures Tc energy-momentum tensor. In the confinement phase the vortex contribution is positive. The thermodynamical significance of the magnetic objects allows us to suggest that the quark gluon plasma may contain a developed network of the magnetic flux tubes. The existence of the vortex network may lead to observable eff...

Chernodub, M N; Zakharov, V I

2008-01-01T23:59:59.000Z

240

Vortex-induced vibration of a circular cylinder with combined in-line and cross-flow motion  

E-Print Network [OSTI]

Deep water, string-like, marine risers subject to strong ocean currents, suffer from vortex-induced vibrations (VIV), where vortex shedding interacts with the structural properties of the riser, resulting in large amplitude ...

Dahl, Jason (Jason Michael)

2008-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "magnetic vortex core" 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

AO Core Competency Worksheet  

Broader source: Energy.gov (indexed) [DOE]

AO Core Competency Worksheet AO Core Competency Worksheet 1 DOE CYBER SECURITY EBK: CORE COMPETENCY TRAINING REQUIREMENTS Key Cyber Security Role: Authorizing Official (AO) Role Definition: The AO is the Senior DOE Management Federal official with the authority to formally assume responsibility and be held fully accountable for operating an information system at an acceptable level of risk. Competency Area: Incident Management Functional Requirement: Manage Competency Definition: Refers to the knowledge and understanding of the processes and procedures required to prevent, detect, investigate, contain, eradicate, and recover from incidents that impact the organizational mission as directed by the DOE Cyber Incident Response Capability (CIRC). Behavioral Outcome: Individuals fulfilling the role of AO will have a working knowledge of policies

242

Earth's Core Hottest Layer  

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

Earth's Core Hottest Layer Earth's Core Hottest Layer Name: Alfred Status: Grade: 6-8 Location: FL Country: USA Date: Spring 2011 Question: Why is the inner core the hottest layer? How is that possible? Replies: There are two factors causing the center of the Earth hotter than various layers of the Earth's. First, the more dense is the layer. The denser layer, the hotter it will be. In addition, the source of the heating is due to heat produced by nuclear decay. These substances tend to be more dense than lower dense substances. So the source of heat (temperature) is higher, the greater will be the temperature. Having said all that, the reasons are rather more complicated in the "real" Earth. If the inner layers were less dense they would rise (bubble) to the "surface" leaving the inner layers more dense and thus hotter layers.

243

2000 BTS Core Databook  

Buildings Energy Data Book [EERE]

0 BTS CORE DATABOOK 0 BTS CORE DATABOOK 2000 BTS CORE DATABOOK OFFICE OF ENERGY EFFICIENCY AND RENEWABLE ENERGY * U.S. DEPARTMENT OF ENERGY This version is dated: August 7, 2000 DISCLAIMER This document was designed for the internal use of the United States Department of Energy. This document was also designed to be occasionally updated and, therefore, this copy may not reflect the most current version. This document was prepared as account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that

244

Probing the anisotropic vortex lattice in the Fe-based superconductor KFe2As2 using small angle neutron scattering  

SciTech Connect (OSTI)

Using small angle neutron scattering, the anisotropy of the magnetic vortex lattice (VL), in the heavily hole-doped pnictide superconductor, KFe2As2, was studied. Well-ordered VL scattering patterns were measured with elds applied in directions between B k c and the basal plane, rotating either towards [100] or [110]. Slightly distorted hexagonal patterns were observed when B k c. However, the scattering pattern distorted strongly as the eld was rotated away from the c- axis. At low eld, the arrangement of vortices is strongly aected by the anisotropy of penetration depth in the plane perpendicular to the eld. By tting the distortion with the anisotropic London model, we obtained an estimate of 3:4 for the anisotropy factor, , between the in-plane and c-axis penetration depths at the lowest temperature studied. The results further reveal VL phase transitions as a function of eld direction. We discuss these transitions using the "Hairy Ball" theorem.

Debeer-Schmitt, Lisa M [ORNL] [ORNL; Dewhurst, Charles [Institut Laue-Langevin (ILL)] [Institut Laue-Langevin (ILL); Kikuchi, Hiroko [Ochanomizu University, Japan] [Ochanomizu University, Japan; Cameron, Alistair [University of Birmingham, The, Birmingham, United Kingdom] [University of Birmingham, The, Birmingham, United Kingdom; Heslop, Richard [University of Birmingham, The, Birmingham, United Kingdom] [University of Birmingham, The, Birmingham, United Kingdom; Forgan, E. M. [University of Birmingham, The, Birmingham, United Kingdom] [University of Birmingham, The, Birmingham, United Kingdom; Bowell, Charlotte [University of Cambridge] [University of Cambridge; White, Jonathon [Laboratory for Neutron Scattering ETHZ & PSI] [Laboratory for Neutron Scattering ETHZ & PSI; Gavilano, Jorge [ETH Zurich, Switzerland] [ETH Zurich, Switzerland

2013-01-01T23:59:59.000Z

245

van Hove singularities and vortex motion in superconductors B. I. Ivlev,1,2  

E-Print Network [OSTI]

´ 78000, Mexico Received 16 February 2001; published 18 June 2001 When vortices move in a type by an electric current, any peculiarity of the vortex radiation friction due to emission of acoustic waves vortices. When a vortex moves under the action of a transport electric current, an electric field

Kunchur, Milind N.

246

Modeling bubble-vortex interactions Modeling and simulation of multiple bubble entrainment and interactions with two  

E-Print Network [OSTI]

Modeling bubble-vortex interactions Modeling and simulation of multiple bubble entrainment, OR 97331. (Dated: 5 November 2010) 1 #12;Modeling bubble-vortex interactions Simulations of bubble direct numerical simulation whereas motion of subgrid bubbles is modeled using Lagrangian track- ing

Apte, Sourabh V.

247

Generation and Propagation of InertiaGravity Waves from Vortex Dipoles and Jets SHUGUANG WANG*  

E-Print Network [OSTI]

Generation and Propagation of Inertia­Gravity Waves from Vortex Dipoles and Jets SHUGUANG WANG) ABSTRACT This study investigates gravity wave generation and propagation from jets within idealized vortex, geostrophic adjust- ment, and spontaneous generation (Fritts and Alexander 2003, and references therein

248

Hopper Multi-Core FAQ  

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

Hopper Multi-Core FAQ Hopper Multi-Core FAQ Hopper Multi-Core FAQ Q. How is Hopper Different than Franklin? A. The new Hopper Phase-II system will have 24 cores per node. Franklin had only four. Q. What else is different? A. There is less memory per core. Hopper has 1.3 GB / core rather than 2.0 GB / core on Franklin. A code using MPI on Hopper may be more likely to exhaust available memory, causing an error. Additionally, Hopper's memory hierarchy is "deeper" and more non-uniform than Franklin's and this can have a big impact on performance in certain cases. Hopper's 24 cores per node are implemented on two sockets, each containing two six-core dies (see the image below). Each of the six-core dies has direct access to one-quarter of the node's total memory. Thus,

249

TMI-2 core examination  

SciTech Connect (OSTI)

The examination of the damaged core at the Three Mile Island Unit 2 (TMI-2) reactor is structured to address the following safety issues: fission product release, transport, and deposition; core coolability; containment integrity; and recriticality during severe accidents; as well as zircaloy cladding ballooning and oxidation during so-called design basis accidents. The numbers of TMI-2 components or samples to be examined, the priority of each examination, the safety issue addressed by each examination, the principal examination techniques to be employed, and the data to be obtained and the principal uses of the data are discussed in this paper.

Hobbins, R.R.; MacDonald, P.E.; Owen, D.E.

1983-01-01T23:59:59.000Z

250

Stripe Domains and First-Order Phase Transition in the Vortex Matter of Anisotropic High-Temperature Superconductors  

E-Print Network [OSTI]

Stripe Domains and First-Order Phase Transition in the Vortex Matter of Anisotropic High-Temperature temperature superconductor and reveal a sharp transition in the state of this phase resulting in regular that can subsequently melt at high temperatures to a vortex liquid, a pinned vortex glassy state that can

Alexei, Koshelev

251

Effect of time-dependent piston velocity program on vortex ring formation in a piston/cylinder arrangement  

E-Print Network [OSTI]

Effect of time-dependent piston velocity program on vortex ring formation in a piston An analytical model describing laminar vortex ring formation in a nozzle flow generator piston/ cylinder.1063/1.2188918 I. INTRODUCTION Vortex rings are usually generated in the laboratory by the motion of a piston

Dabiri, John O.

252

arXiv:1206.2498v2[cond-mat.other]19Nov2012 Quantum vortex reconnections  

E-Print Network [OSTI]

, and parts of the initial vortical tubes can be left behind as vortex threads, which then undergo successivearXiv:1206.2498v2[cond-mat.other]19Nov2012 Quantum vortex reconnections S. Zuccher,1 M. Caliari,1 A with time before and after the vor- tex reconnection. We also compute vortex reconnections using the Biot

Caliari, Marco

253

The role of boundary conditions in a simple model of incipient vortex breakdown F. Gallaire and J.-M. Chomaz  

E-Print Network [OSTI]

. In the labora- tory, it is preferentially studied in vortex tubes, where it is seen in many cases to give riseThe role of boundary conditions in a simple model of incipient vortex breakdown F. Gallaire and J of a hairpin vortex in a shear-thinning fluid governed by a power-law model Phys. Fluids 25, 101703 (2013); 10

Boyer, Edmond

254

Quantum dynamics of a vortex in a Josephson junction  

SciTech Connect (OSTI)

We investigate the tunneling character of vortex in an asymmetrical potential well with a finite barrier by using the periodic instanton method. We obtain the total decay rate which is valid for the entire range of temperature and show how it reduces to the appropriate results for the classical thermal activation at high temperatures, the thermally assisted tunneling at intermediate temperatures, and the pure quantum tunneling at low temperature. We can even give the exact definition of the 'crossover' temperature and find experimental data to support our theoretical analysis.

Li Hong; Liu Wuming [Joint Laboratory of Advanced Technology in Measurements, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080 (China); Shen Shunqing [Department of Physics, University of Hong Kong, Pokfulam Road, Hong Kong (China); Liang Jiuqing [Institute of Theoretical Physics, Shanxi University, Taiyuan, Shanxi 030006 (China)

2005-07-01T23:59:59.000Z

255

Collective Effects in Vortex Movements in Complex Plasmas  

Science Journals Connector (OSTI)

We study the onset and characteristics of vortices in complex (dusty) plasmas using two-dimensional simulations in a setup modeled after the PK-3 Plus laboratory. A small number of microparticles initially self-arranges in a monolayer around the void. As additional particles are introduced, an extended system of vortices develops due to a nonzero curl of the plasma forces. We demonstrate a shear-thinning effect in the vortices. Velocity structure functions and the energy and enstrophy spectra show that vortex flow turbulence is present that is in essence of the “classical” Kolmogorov type.

Mierk Schwabe, Sergey Zhdanov, Christoph Räth, David B. Graves, Hubertus M. Thomas, and Gregor E. Morfill

2014-03-19T23:59:59.000Z

256

Interaction of Josephson Junction and Distant Vortex in Narrow Thin-Film Superconducting Strips  

SciTech Connect (OSTI)

The phase difference between the banks of an edge-type planar Josephson junction crossing the narrow thin-film strip depends on wether or not vortices are present in the junction banks. For a vortex close to the junction this effect has been seen by Golod, Rydh, and Krasnov [Phys. Rev. Lett. 104, 227003 (2010)], who showed that the vortex may turn the junction into ? type. It is shown here that even if the vortex is far away from the junction, it still changes the 0 junction to a ? junction when situated close to the strip edges. Within the approximation used, the effect is independent of the vortex-junction separation, a manifestation of the topology of the vortex phase which extends to macroscopic distances of superconducting coherence.

Kogan, V. G. [Ames Laboratory; Mints, R. G. [Tel Aviv University

2014-01-31T23:59:59.000Z

257

Static solitons of the sine-Gordon equation and equilibrium vortex structure in Josephson junctions  

SciTech Connect (OSTI)

The problem of vortex structure in a single Josephson junction in an external magnetic field, in the absence of transport currents, is reconsidered from a new mathematical point of view. In particular, we derive a complete set of exact analytical solutions representing all the stationary points (minima and saddle-points) of the relevant Gibbs free-energy functional. The type of these solutions is determined by explicit evaluation of the second variation of the Gibbs free-energy functional. The stable (physical) solutions minimizing the Gibbs free-energy functional form an infinite set and are labeled by a topological number N{sub v}=0,1,2,... . Mathematically, they can be interpreted as nontrivial 'vacuum' (N{sub v}=0) and static topological solitons (N{sub v}=1,2,...) of the sine-Gordon equation for the phase difference in a finite spatial interval: solutions of this kind were not considered in previous literature. Physically, they represent the Meissner state (N{sub v}=0) and Josephson vortices (N{sub v}=1,2,...). Major properties of the new physical solutions are thoroughly discussed. An exact, closed-form analytical expression for the Gibbs free energy is derived and analyzed numerically. Unstable (saddle-point) solutions are also classified and discussed.

Kuplevakhsky, S. V.; Glukhov, A. M. [B. I. Verkin Institute for Low Temperature Physics and Engineering, National Academy of Sciences of Ukraine, 47 Lenin Avenue, 61103 Kharkov (Ukraine)

2006-01-01T23:59:59.000Z

258

SECA Core Technology Program  

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

January 27 - January 27 - 28, 2005 Workshop Peer Review Rating Results Summary Donald Collins SECA Core January 2005 Workshop Peer Review Summary - DWC,PM-30,3-10-05 2 of 21 Review Process Summary * Core Technology Project Presentations - Project Objectives & Results - Non-proprietary Information - Industry, National Lab & University Participation * Verbal & Written Constructive Comments - Written Comments on Peer Review Forms - Industry Verbal Feedback at Workshop * Core Participant Review & Reply to Comments - Reply to Comment Issues * DOE NETL Redirect Projects as Needed M a t e r i a l s C o n t r o l s & D i a g n o s t i c s P o w e r E le c t r o n ic s F u e l P r o c e s s i n g Manufacturing M o d e li n g & S im u la ti o n SECA Core January 2005 Workshop Peer Review Summary - DWC,PM-30,3-10-05 3 of 21 Peer Review Questions

259

SECA Core Technology Program  

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

May 12 - May 12 - 13, 2004 Workshop Peer Review Rating Results Summary Donald Collins SECA Core May 2004 Workshop Peer Review Summary - DWC,PM-30,5-21-04 2 of 16 Review Process Summary * Core Technology Project Presentations - Project Objectives & Results - Non-proprietary Information - Industry, National Lab & University Participation * Verbal & Written Constructive Comments - Written Comments on Peer Review Forms - Industry Verbal Feedback at Workshop * Core Participant Review & Reply to Comments - Reply to Comment Issues * DOE NETL Redirect Projects as Needed M a t e r i a l s C o n t r o l s & D i a g n o s t i c s P o w e r E le c t r o n ic s F u e l P r o c e s s i n g Manufacturing M o d e li n g & S im u la ti o n SECA Core May 2004 Workshop Peer Review Summary - DWC,PM-30,5-21-04 3 of 16 Peer Review Questions

260

Plan ?: core or cusp?  

Science Journals Connector (OSTI)

......research-article Article Plan beta: core or cusp? Thomas...Breddels (2013) for a detailed review of the more sophisticated numerical...is available for each star (standard technique). Large data sets...velocity space, we use the standard definition, for the velocity......

Thomas D. Richardson; Douglas Spolyar; Matthew D. Lehnert

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "magnetic vortex core" 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

Core competence (knowledge) (skill)  

E-Print Network [OSTI]

Core competence 8 5~8 2 3 4 5 6 7 8 PPS003 Ver. 1.1 2011/03/07 #12; 2 (knowledge) (skill) (attitude) Set of skill, knowledge or attitude which should be learned or acquired by each, 2000) (knowledge) (skill) (attitude) Set of skill, knowledge or attitude which should be learned

Wu, Yih-Min

262

Dynamics of core accretion  

Science Journals Connector (OSTI)

......formation, the accretor is of course a rocky planetary core, on to which gas accretion...both cases, the distributions are nearly flat at large distances (i.e.-R H...the evolution of the simulation, using a safety factor of J- 4. Nevertheless, at time......

Andrew F. Nelson; Maximilian Ruffert

2013-01-01T23:59:59.000Z

263

Dynamics of core accretion  

Science Journals Connector (OSTI)

......the accretor is of course a rocky planetary core, on to which...the distributions are nearly flat at large distances (i.e...numerically induced collapse through violation of the Jeans criterion (Truelove...of the simulation, using a safety factor of J- 4. Nevertheless......

Andrew F. Nelson; Maximilian Ruffert

2013-01-01T23:59:59.000Z

264

MAGNETIC NEUTRON SCATTERING  

SciTech Connect (OSTI)

Much of our understanding of the atomic-scale magnetic structure and the dynamical properties of solids and liquids was gained from neutron-scattering studies. Elastic and inelastic neutron spectroscopy provided physicists with an unprecedented, detailed access to spin structures, magnetic-excitation spectra, soft-modes and critical dynamics at magnetic-phase transitions, which is unrivaled by other experimental techniques. Because the neutron has no electric charge, it is an ideal weakly interacting and highly penetrating probe of matter's inner structure and dynamics. Unlike techniques using photon electric fields or charged particles (e.g., electrons, muons) that significantly modify the local electronic environment, neutron spectroscopy allows determination of a material's intrinsic, unperturbed physical properties. The method is not sensitive to extraneous charges, electric fields, and the imperfection of surface layers. Because the neutron is a highly penetrating and non-destructive probe, neutron spectroscopy can probe the microscopic properties of bulk materials (not just their surface layers) and study samples embedded in complex environments, such as cryostats, magnets, and pressure cells, which are essential for understanding the physical origins of magnetic phenomena. Neutron scattering is arguably the most powerful and versatile experimental tool for studying the microscopic properties of the magnetic materials. The magnitude of the cross-section of the neutron magnetic scattering is similar to the cross-section of nuclear scattering by short-range nuclear forces, and is large enough to provide measurable scattering by the ordered magnetic structures and electron spin fluctuations. In the half-a-century or so that has passed since neutron beams with sufficient intensity for scattering applications became available with the advent of the nuclear reactors, they have became indispensable tools for studying a variety of important areas of modern science, ranging from large-scale structures and dynamics of polymers and biological systems, to electronic properties of today's technological materials. Neutron scattering developed into a vast field, encompassing many different experimental techniques aimed at exploring different aspects of matter's atomic structure and dynamics. Modern magnetic neutron scattering includes several specialized techniques designed for specific studies and/or particular classes of materials. Among these are magnetic reflectometry aimed at investigating surfaces, interfaces, and multilayers, small-angle scattering for the large-scale structures, such as a vortex lattice in a superconductor, and neutron spin-echo spectroscopy for glasses and polymers. Each of these techniques and many others offer exciting opportunities for examining magnetism and warrant extensive reviews, but the aim of this chapter is not to survey how different neutron-scattering methods are used to examine magnetic properties of different materials. Here, we concentrate on reviewing the basics of the magnetic neutron scattering, and on the recent developments in applying one of the oldest methods, the triple axis spectroscopy, that still is among the most extensively used ones. The developments discussed here are new and have not been coherently reviewed. Chapter 2 of this book reviews magnetic small-angle scattering, and modern techniques of neutron magnetic reflectometry are discussed in Chapter 3.

ZALIZNYAK,I.A.; LEE,S.H.

2004-07-30T23:59:59.000Z

265

Not All Nanodisk Magnetic Vortices Are Created Equally  

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

Not All Nanodisk Magnetic Vortices Are Created Equally Print Not All Nanodisk Magnetic Vortices Are Created Equally Print Magnetic vortices - hurricanes of magnetism only a few atoms across - have generated intense interest in the high-tech community because of their potential application in nonvolatile random access memory (RAM) data storage systems. A team of researchers led by Peter Fischer and Mi-Young Im of the Center for X-Ray Optics (CXRO) worked in collaboration with scientists in Japan to discover that, contrary to what was previously believed, the formation of magnetic vortices in ferromagnetic nanodisks is an asymmetric phenomenon. This breaking of symmetry could lead to failure in a data storage device during its initialization process. These new findings indicate that the road to magnetic vortex RAM might be more difficult to navigate than previously supposed, but there might be unexpected rewards as well.

266

Not All Nanodisk Magnetic Vortices Are Created Equally  

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

Not All Nanodisk Magnetic Vortices Are Created Equally Print Not All Nanodisk Magnetic Vortices Are Created Equally Print Magnetic vortices - hurricanes of magnetism only a few atoms across - have generated intense interest in the high-tech community because of their potential application in nonvolatile random access memory (RAM) data storage systems. A team of researchers led by Peter Fischer and Mi-Young Im of the Center for X-Ray Optics (CXRO) worked in collaboration with scientists in Japan to discover that, contrary to what was previously believed, the formation of magnetic vortices in ferromagnetic nanodisks is an asymmetric phenomenon. This breaking of symmetry could lead to failure in a data storage device during its initialization process. These new findings indicate that the road to magnetic vortex RAM might be more difficult to navigate than previously supposed, but there might be unexpected rewards as well.

267

Not All Nanodisk Magnetic Vortices Are Created Equally  

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

Not All Nanodisk Magnetic Vortices Are Created Equally Print Not All Nanodisk Magnetic Vortices Are Created Equally Print Magnetic vortices - hurricanes of magnetism only a few atoms across - have generated intense interest in the high-tech community because of their potential application in nonvolatile random access memory (RAM) data storage systems. A team of researchers led by Peter Fischer and Mi-Young Im of the Center for X-Ray Optics (CXRO) worked in collaboration with scientists in Japan to discover that, contrary to what was previously believed, the formation of magnetic vortices in ferromagnetic nanodisks is an asymmetric phenomenon. This breaking of symmetry could lead to failure in a data storage device during its initialization process. These new findings indicate that the road to magnetic vortex RAM might be more difficult to navigate than previously supposed, but there might be unexpected rewards as well.

268

Not All Nanodisk Magnetic Vortices Are Created Equally  

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

Not All Nanodisk Magnetic Vortices Are Created Equally Print Not All Nanodisk Magnetic Vortices Are Created Equally Print Magnetic vortices - hurricanes of magnetism only a few atoms across - have generated intense interest in the high-tech community because of their potential application in nonvolatile random access memory (RAM) data storage systems. A team of researchers led by Peter Fischer and Mi-Young Im of the Center for X-Ray Optics (CXRO) worked in collaboration with scientists in Japan to discover that, contrary to what was previously believed, the formation of magnetic vortices in ferromagnetic nanodisks is an asymmetric phenomenon. This breaking of symmetry could lead to failure in a data storage device during its initialization process. These new findings indicate that the road to magnetic vortex RAM might be more difficult to navigate than previously supposed, but there might be unexpected rewards as well.

269

Not All Nanodisk Magnetic Vortices Are Created Equally  

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

Not All Nanodisk Magnetic Vortices Are Created Equally Print Not All Nanodisk Magnetic Vortices Are Created Equally Print Magnetic vortices - hurricanes of magnetism only a few atoms across - have generated intense interest in the high-tech community because of their potential application in nonvolatile random access memory (RAM) data storage systems. A team of researchers led by Peter Fischer and Mi-Young Im of the Center for X-Ray Optics (CXRO) worked in collaboration with scientists in Japan to discover that, contrary to what was previously believed, the formation of magnetic vortices in ferromagnetic nanodisks is an asymmetric phenomenon. This breaking of symmetry could lead to failure in a data storage device during its initialization process. These new findings indicate that the road to magnetic vortex RAM might be more difficult to navigate than previously supposed, but there might be unexpected rewards as well.

270

Not All Nanodisk Magnetic Vortices Are Created Equally  

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

Not All Nanodisk Magnetic Vortices Are Created Equally Print Not All Nanodisk Magnetic Vortices Are Created Equally Print Magnetic vortices - hurricanes of magnetism only a few atoms across - have generated intense interest in the high-tech community because of their potential application in nonvolatile random access memory (RAM) data storage systems. A team of researchers led by Peter Fischer and Mi-Young Im of the Center for X-Ray Optics (CXRO) worked in collaboration with scientists in Japan to discover that, contrary to what was previously believed, the formation of magnetic vortices in ferromagnetic nanodisks is an asymmetric phenomenon. This breaking of symmetry could lead to failure in a data storage device during its initialization process. These new findings indicate that the road to magnetic vortex RAM might be more difficult to navigate than previously supposed, but there might be unexpected rewards as well.

271

Not All Nanodisk Magnetic Vortices Are Created Equally  

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

Not All Nanodisk Magnetic Vortices Are Created Equally Print Not All Nanodisk Magnetic Vortices Are Created Equally Print Magnetic vortices - hurricanes of magnetism only a few atoms across - have generated intense interest in the high-tech community because of their potential application in nonvolatile random access memory (RAM) data storage systems. A team of researchers led by Peter Fischer and Mi-Young Im of the Center for X-Ray Optics (CXRO) worked in collaboration with scientists in Japan to discover that, contrary to what was previously believed, the formation of magnetic vortices in ferromagnetic nanodisks is an asymmetric phenomenon. This breaking of symmetry could lead to failure in a data storage device during its initialization process. These new findings indicate that the road to magnetic vortex RAM might be more difficult to navigate than previously supposed, but there might be unexpected rewards as well.

272

Core Holes | Open Energy Information  

Open Energy Info (EERE)

Core Holes Core Holes Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Core Holes Details Activities (8) Areas (7) Regions (0) NEPA(0) Exploration Technique Information Exploration Group: Drilling Techniques Exploration Sub Group: Exploration Drilling Parent Exploration Technique: Exploration Drilling Information Provided by Technique Lithology: Core holes are drilled to identify lithology and mineralization Stratigraphic/Structural: Retrieved samples can be used to identify fracture networks or faults Hydrological: Thermal: Thermal conductivity measurements can be done on retrieved samples. Dictionary.png Core Holes: A core hole is a well that is drilled using a hallow drill bit coated with synthetic diamonds for the purposes of extracting whole rock samples from

273

Core transport studies in fusion devices  

E-Print Network [OSTI]

The turbulence in magnetically confined fusion plasmas has important and non-trivial effects on the quality of the energy confinement. These effects are hard to make a quantitative assessment of analytically. The problem investigated in this article is the transport of energy and particles, in particular impurities, in a Tokamak plasma. Impurities from the walls of the plasma vessel cause energy losses if they reach the plasma core. It is therefore important to understand the transport mechanisms to prevent impurity accumulation and minimize losses. This is an area of research where turbulence plays a major role and is intimately associated with the performance of future fusion reactors, such as ITER.

Strand, Pär; Nordman, Hans

2010-01-01T23:59:59.000Z

274

Random center vortex lines in continuous 3D space-time  

E-Print Network [OSTI]

We present a model of center vortices, represented by closed random lines in continuous 2+1- dimensional space- time. These random lines are modeled as being piece-wise linear and an ensemble is generated by Monte Carlo methods. The physical space in which the vortex lines are defined is a cuboid with periodic boundary conditions. Besides moving, growing and shrinking of the vortex configuration, also reconnections are allowed. Our ensemble therefore contains not a fixed, but a variable number of closed vortex lines. This is expected to be important for realizing the deconfining phase transition. Using the model, we study both vortex percolation and the potential V (R) between quark and anti-quark as a function of distance R at different vortex densities, vortex segment lengths, reconnection conditions and at different temperatures. We have found three deconfinement phase transitions, as a function of density, as a function of vortex segment length, and as a function of temperature. The model reproduces the qualitative features of confinement physics seen in SU(2) Yang-Mills theory.

Roman Höllwieser; Derar Altarawneh; Michael Engelhardt

2014-11-26T23:59:59.000Z

275

Core Measure Results  

Broader source: Energy.gov (indexed) [DOE]

Core Measure Core Measure Results FY 07 Results FY 08 Results FY 09 Results FY 10 Target FY 10 Customer Perspective: Customer Satisfaction: -Timeliness NM 81 NM NM NM -Quality NM 90 NM NM NM Effective Service Partnership: -Extent of Customer Satisfaction with the responsiveness, etc. NM 87 NM NM NM Internal Business Perspective: Acquisition Excellence: -Extent to which internal quality control systems are effective 86 87 84 87 88 Most Effective Use of Contracting Approaches to Maximize Efficiency and Cost Effectiveness: Use of Electronic Commerce: - % of delivery & purchase orders issued electronically as a % of total simplified actions 70 72 89 99 100 - % of new competitive transactions > $100K conducted through EC 70 72 91 100 95 Performance Based Service Contracts: - PBSCs awarded as a % of eligible new

276

Banded electromagnetic stator core  

DOE Patents [OSTI]

A stator core for an electromagnetic pump includes a plurality of circumferentially adjoining groups of flat laminations disposed about a common centerline axis and collectively defining a central bore and a discontinuous outer perimeter, with adjacent groups diverging radially outwardly to form V-shaped gaps. An annular band surrounds the groups and is predeterminedly tensioned to clamp together the laminations, and has a predetermined flexibility in a radial direction to form substantially straight bridge sections between the adjacent groups.

Fanning, Alan W. (San Jose, CA); Gonzales, Aaron A. (San Jose, CA); Patel, Mahadeo R. (San Jose, CA); Olich, Eugene E. (Aptos, CA)

1996-01-01T23:59:59.000Z

277

Banded electromagnetic stator core  

DOE Patents [OSTI]

A stator core for an electromagnetic pump includes a plurality of circumferentially adjoining groups of flat laminations disposed about a common centerline axis and collectively defining a central bore and a discontinuous outer perimeter, with adjacent groups diverging radially outwardly to form V-shaped gaps. An annular band surrounds the groups and is predeterminedly tensioned to clamp together the laminations, and has a predetermined flexibility in a radial direction to form substantially straight bridge sections between the adjacent groups.

Fanning, Alan W. (San Jose, CA); Gonzales, Aaron A. (San Jose, CA); Patel, Mahadeo R. (San Jose, CA); Olich, Eugene E. (Aptos, CA)

1994-01-01T23:59:59.000Z

278

Variable depth core sampler  

DOE Patents [OSTI]

A variable depth core sampler apparatus comprising a first circular hole saw member, having longitudinal sections that collapses to form a point and capture a sample, and a second circular hole saw member residing inside said first hole saw member to support the longitudinal sections of said first hole saw member and prevent them from collapsing to form a point. The second hole saw member may be raised and lowered inside said first hole saw member.

Bourgeois, Peter M. (Hamburg, NY); Reger, Robert J. (Grand Island, NY)

1996-01-01T23:59:59.000Z

279

Electromagnetic pump stator core  

DOE Patents [OSTI]

A stator core for supporting an electrical coil includes a plurality of groups of circumferentially abutting flat laminations which collectively form a bore and perimeter. A plurality of wedges are interposed between the groups, with each wedge having an inner edge and a thicker outer edge. The wedge outer edges abut adjacent ones of the groups to provide a continuous path around the perimeter. 21 figures.

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

1995-01-17T23:59:59.000Z

280

Banded electromagnetic stator core  

DOE Patents [OSTI]

A stator core for an electromagnetic pump includes a plurality of circumferentially adjoining groups of flat laminations disposed about a common centerline axis and collectively defining a central bore and a discontinuous outer perimeter, with adjacent groups diverging radially outwardly to form V-shaped gaps. An annular band surrounds the groups and is predeterminedly tensioned to clamp together the laminations, and has a predetermined flexibility in a radial direction to form substantially straight bridge sections between the adjacent groups. 5 figs.

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

1996-06-11T23:59:59.000Z

Note: This page contains sample records for the topic "magnetic vortex core" 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

Banded electromagnetic stator core  

DOE Patents [OSTI]

A stator core for an electromagnetic pump includes a plurality of circumferentially adjoining groups of flat laminations disposed about a common centerline axis and collectively defining a central bore and a discontinuous outer perimeter, with adjacent groups diverging radially outwardly to form V-shaped gaps. An annular band surrounds the groups and is predeterminedly tensioned to clamp together the laminations, and has a predetermined flexibility in a radial direction to form substantially straight bridge sections between the adjacent groups. 5 figures.

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

1994-04-05T23:59:59.000Z

282

Variable depth core sampler  

DOE Patents [OSTI]

A variable depth core sampler apparatus is described comprising a first circular hole saw member, having longitudinal sections that collapses to form a point and capture a sample, and a second circular hole saw member residing inside said first hole saw member to support the longitudinal sections of said first hole saw member and prevent them from collapsing to form a point. The second hole saw member may be raised and lowered inside said first hole saw member. 7 figs.

Bourgeois, P.M.; Reger, R.J.

1996-02-20T23:59:59.000Z

283

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

SciTech Connect (OSTI)

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

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

2013-09-01T23:59:59.000Z

284

What can the observed rotation of the Earth's inner core reveal about the state of the outer core?  

E-Print Network [OSTI]

present a model intermediate between these two extremes. In particular, I retain the simplicity of the model of Aurnou et al. by kinematically prescribing a thermal wind and poloidal magnetic ¢eld. By doing¡ect, the relationship between the inner core's rotation rate and the strength of the thermal wind is more complicated

Haase, Markus

285

Core Analysis | Open Energy Information  

Open Energy Info (EERE)

Core Analysis Core Analysis Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Core Analysis Details Activities (41) Areas (28) Regions (2) NEPA(0) Exploration Technique Information Exploration Group: Lab Analysis Techniques Exploration Sub Group: Rock Lab Analysis Parent Exploration Technique: Rock Lab Analysis Information Provided by Technique Lithology: Core analysis is done to define lithology. Stratigraphic/Structural: Core analysis can locate faults or fracture networks. Oriented core can give additional important information on anisotropy. Hydrological: Thermal: Thermal conductivity can be measured from core samples. Cost Information Low-End Estimate (USD): 2,000.00200,000 centUSD 2 kUSD 0.002 MUSD 2.0e-6 TUSD / 30 foot core Median Estimate (USD): 10,000.001,000,000 centUSD

286

A 3.55 keV line from $\\text{DM}\\rightarrow a \\rightarrow ?$: predictions for cool-core and non-cool-core clusters  

E-Print Network [OSTI]

We further study a scenario in which a 3.55 keV X-ray line arises from decay of dark matter to an axion-like particle (ALP), that subsequently converts to a photon in astrophysical magnetic fields. We perform numerical simulations of Gaussian random magnetic fields with radial scaling of the magnetic field magnitude with the electron density, for both cool-core `Perseus' and non-cool-core `Coma' electron density profiles. Using these, we quantitatively study the resulting signal strength and morphology for cool-core and non-cool-core clusters. Our study includes the effects of fields of view that cover only the central part of the cluster, the effects of offset pointings on the radial decline of signal strength and the effects of dividing clusters into annuli. We find good agreement with current data and make predictions for future analyses and observations.

Joseph P. Conlon; Andrew J. Powell

2014-06-20T23:59:59.000Z

287

Theories of the Earth's Magnetism  

Science Journals Connector (OSTI)

The earth's core may be assumed to consist of fluid metal surrounding a solid inner core which probably contains a source of heat to drive convection, but it is not possible at present to select between various possible types of convective motion in the fluid core. Types considered are characterized by some sort of radial flow streams and a tendency for the fluid to rotate on the average more rapidly near the axis to conserve angular momentum during the circulation. Though the actual flow may be quite complicated, proposed mechanisms for generating a terrestrial magnetic field are considered for some oversimplified flow patterns in an attempt to indicate what features of the flow may provide the most important possibilities for field generation. It is suggested that, without a field to absorb the energy, the flow would be accelerated indefinitely and would evolve through a succession of flow patterns, some of which would be expected to have the properties to generate a field capable of preventing further acceleration and prolonging the status quo, thus making it likely that the earth should have a field.The generating mechanisms discussed include two induction theories, the dynamo theory of Elsasser and Bullard, which is discussed at length both in terms of velocity-current systems portrayed by elaborate models and in hydromagnetic terms, and the "twisted-kink" theory of Alvèn which is discussed only hydromagnetically. Each of these theories depends on amplifying an initial stray magnetic field up to a point where it dissipates all of the available energy, and is at least in this respect analogous to a conventional electrical generator but without a ferromagnetic core. Other mechanisms discussed depend either on the thermoelectric effect with junctions at the core-mantle interface or on a combination of thermoelectric and Hall effects in the core and mantle.If the convective flow is rather irregular, the observed slow westward drift of the detailed pattern of the earth's field is attributed to the vanishing of the total torque on the core by the magnetic field threading through the core and mantle, as a result of an eastward drag on the outer part of the core rotating more slowly in space and a westward drag on the more rapidly rotating part of the core near the axis, with the presumption that the observed magnetic pattern is characteristic of the westward-drifting outer part. If the flow instead involves a jet stream, the flow in the jet may under some circumstances be expected to be eastward for reasons comparable to temperate-zone meteorology, so the magnetic field should exert a westward drag on it leading to the westward drift of the flow pattern.

D. R. Inglis

1955-04-01T23:59:59.000Z

288

High-voltage air-core pulse transformers  

SciTech Connect (OSTI)

General types of air core pulse transformers designed for high voltage pulse generation and energy transfer applications are discussed with special emphasis on pulse charging systems which operate up to the multi-megavolt range. The design, operation, dielectric materials, and performance are described. It is concluded that high voltage air core pulse transformers are best suited to applications outside the normal ranges of conventional magnetic core transformers. In general these include charge transfer at high power levels and fast pulse generation with comparatively low energy. When properly designed and constructed, they are capable of delivering high energy transfer efficiency and have demonstrated superior high voltage endurance. The principal disadvantage of high voltage air core transformers is that they are not generally available from commercial sources. Consequently, the potential user must become thoroughly familiar with all aspects of design, fabrication and system application before he can produce a high performance transformer system. (LCL)

Rohwein, G. J.

1981-01-01T23:59:59.000Z

289

Magnetic Spinner  

Science Journals Connector (OSTI)

A science toy sometimes called the “magnetic spinner” is an interesting class demonstration to illustrate the principles of magnetic levitation. It can also be used to demonstrate Faraday's law and a horizontally suspended physical pendulum. The levitated part contains two circular magnets encased in a plastic housing. Each magnet stays above two triangular magnets fixed to the base. The magnetic repulsive force experienced by the circular magnets is independent of their orientation; therefore the holder of these magnets can be rotated without affecting its stability. The holder with the circular magnets can be oscillated up and down as a horizontally suspended physical pendulum.

P. J. Ouseph

2006-01-01T23:59:59.000Z

290

Magnetic measurements of recent sediments from Big Moose Lake, Adirondack Mountains, N.Y., USA  

Science Journals Connector (OSTI)

Measurements of anhysteretic (ARM) and isothermal (IRM) remanences in cores 6 and 8 from Big Moose Lake reveal evidence for changes in magnetic mineralogy and grain size within and between the two cores. It is...

Frank Oldfield

1990-01-01T23:59:59.000Z

291

Ideal MHD stability calculations in presence of magnetic separatrices F. Alladioa  

E-Print Network [OSTI]

(Flux-Core-Spheromak or Chandrasekhar-Kendall-Furth configurations), which embed a magnetic separatrix. Comparison between: a) a CKF configuration; b) the PROTO-SPHERA Flux-Core-Spheromak. X

Paris-Sud XI, Université de

292

Core Competency Worksheets for Significant Cybersecurity Roles...  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

Core Competency Worksheets for Significant Cybersecurity Roles Core Competency Worksheets for Significant Cybersecurity Roles The OCIO has developed core competency worksheets for...

293

Magnetism Digest  

Science Journals Connector (OSTI)

... and Institute of Electrical and Electronic Engineers, on the occasion of their annual conferences on magnetism and magnetic materials in the United States, have sponsored the production of a Magnetic ... references, drawn from a large number of sources, to work in the field of magnetism and magnetic materials published in the preceding year. They therefore provide a very convenient ...

J. H. PHILLIPS

1966-06-25T23:59:59.000Z

294

Observation of Dirac Monopoles in a Synthetic Magnetic Field  

E-Print Network [OSTI]

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

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

2014-08-13T23:59:59.000Z

295

2001 BTS Core Databook  

Buildings Energy Data Book [EERE]

1 BTS CORE 1 BTS CORE DATABOOK OFFICE OF ENERGY EFFICIENCY AND RENEWABLE ENERGY U.S. DEPARTMENT OF ENERGY This version is dated: November 30, 2001 REVISED data tables on the web site that have been changed since November 30, 2001 include tables: 5.6.7 5.6.8 5.6.9 5.10.8 5.10.9 5.10.10 5.10.11 5.10.12 5.10.13 5.10.14 5.10.15 5.10.16 5.10.17 5.10.18 NEW data tables on the web site that have been added since July 13, 2001 include tables: 5.6.14 5.9.7 5.9.8 5.9.9 REVISED data tables on the web site that have been changed since July 13, 2001 include tables: 4.1.1 4.1.2 4.1.4 4.1.5 4.2.1 4.2.2 4.2.3 4.2.4 4.2.5 4.2.9 4.3.1 4.3.2 4.3.3 4.3.4 4.5.1 4.5.2 4.5.3 5.1.2 5.3.1 5.8.1 5.10.1 6.2.4 7.1.8 7.3.3 These tables are not included in this version of the 2001 BTS Core Databook. DISCLAIMER DISCLAIMER DISCLAIMER DISCLAIMER

296

Core-tube data logger  

SciTech Connect (OSTI)

Wireline core drilling, increasingly used for geothermal exploration, employs a core-tube to capture a rock core sample during drilling. Three types of core-tube data loggers (CTDL) have been built and tested to date by Sandia national Laboratories. They are: (1) temperature-only logger, (2) temperature/inclinometer logger and (3) heat-shielded temperature/inclinometer logger. All were tested during core drilling operations using standard wireline diamond core drilling equipment. While these tools are designed for core-tube deployment, the tool lends itself to be adapted to other drilling modes and equipment. Topics covered in this paper include: (1) description on how the CTDLs are implemented, (2) the components of the system, (3) the type of data one can expect from this type of tool, (4) lessons learned, (5) comparison to its counterpart and (6) future work.

Henfling, J.A.; Normann, R.A.; Knudsen, S.; Drumheller, D.

1997-01-01T23:59:59.000Z

297

CFD Numerical Simulation of Vortex-Induced Vibration of a Stay Cable under a Wind Profile  

Science Journals Connector (OSTI)

VIV (Vortex-induced vibration) of a stay cable subjected to a wind profile is numerically simulated through combining CFD ... numerical model. Under a profile of mean wind speed, unsteady aerodynamic lift coeffic...

Wenli Chen; Hui Li

2009-01-01T23:59:59.000Z

298

Optimal Excitation of Asymmetric Perturbations on an Axisymmetric Barotropic Vortex: A linear Singular Value Analysis  

Science Journals Connector (OSTI)

Singular vectors on a barotropic circular vortex consisting of three regions of piecewise-constant vorticity are investigated under the L2-norm to reveal the shape and growth rate of possible perturbations that may contribute to the formation of ...

Toshihisa Itano

299

Dynamical mass of a quantum vortex in a Josephson junction array  

SciTech Connect (OSTI)

The real-time response to a small external perturbation of a vortex in a quantum Josephson junction array, with long-range Coulomb interaction between Cooper pairs, is analyzed. While the static damping is zero for vortex velocities below some threshold value v{sub th} (which implies the possibility of ballistic motion), a dynamical friction due to the coupling to the plasma oscillations is always present for frequencies higher than a given threshold {omega}{sub th}. The latter approaches zero when the velocity increases to v{sub th}. However, radiative dissipation of the vortex affects the threshold for ballistic motion. We discuss the conditions under which a mass can be defined for the vortex as a quantum particle. {copyright} {ital 1997} {ital The American Physical Society}

Eckern, U. [Institut fuer Physik, Universitaet Augsburg, D-86135 Augsburg (Germany)] [Institut fuer Physik, Universitaet Augsburg, D-86135 Augsburg (Germany); Luciano, G.; Tagliacozzo, A. [Dipartimento di Scienze Fisiche, Universita di Napoli, Mostra dOltremare Pad. 19, I-80125 Napoli (Italy)] [Dipartimento di Scienze Fisiche, Universita di Napoli, Mostra dOltremare Pad. 19, I-80125 Napoli (Italy); [Istituto Nazionale di Fisica della Materia (INFM), I-16152 Genova (Italy)

1997-12-01T23:59:59.000Z

300

E-Print Network 3.0 - axially-symmetric cyclonic vortex Sample...  

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

> >> 1 1 APRIL 2002 1213W A N G 2002 American Meteorological Society Summary: and wind fields of the vortex Rossby waves are quasi-balanced, with confluent cyclonic (divergent... ,...

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


301

Ultraviolet vortex generation using periodically bonded ?-BaB2O4 device  

Science Journals Connector (OSTI)

This paper describes the first demonstration of ultraviolet (266nm) vortex generation using the combination of a frequency-doubled nanosecond green laser, a spiral phase plate, and a...

Sasaki, Yuta; Koyama, Mio; Miyamoto, Katsuhiko; Ariga, Yoshimi; Onda, Tomomi; Shoji, Ichiro; Omatsu, Takashige

2014-01-01T23:59:59.000Z

302

Vortex-Induced Vibration of a slender horizontal cylinder in currents and waves  

E-Print Network [OSTI]

Vortex-Induced Vibration (VIV) is a concern when dealing with slender, flexible structural members of deepwater platforms. While much is known about the characteristics of VIV in uniform and sheared current flows, very little is known about...

Chitwood, James Scott

2012-06-07T23:59:59.000Z

303

Application of fiber Bragg grating based strain sensor in pipeline vortex-induced vibration measurement  

Science Journals Connector (OSTI)

The vortex-induced vibrations (VIV) is an important topic of ... of different methods have been applied to the measurement of VIV, especially for the elongated, ... in stainless steel tubes were applied to the measurement

Liang Ren; ZiGuang Jia; Michael Siu Chun Ho…

2014-09-01T23:59:59.000Z

304

The Roles of Vortex Rossby Waves in Hurricane Secondary Eyewall Formation  

Science Journals Connector (OSTI)

A high-resolution, full-physics model initiated with an idealized tropical cyclone–like vortex is used to simulate and investigate the secondary eyewall formation. The beta skirt axisymmetrization (BSA) hypothesis previously proposed is examined ...

Xin Qiu; Zhe-Min Tan; Qingnong Xiao

2010-06-01T23:59:59.000Z

305

Vortex life cycles in two-and three-layer quasi-geostrophic models  

E-Print Network [OSTI]

Coherent vortices and their properties were studied in two- and three-layer quasi-geostrophic beta-plane turbulence. Much research has discussed vortex characteristics in a number of applications, but no significant study of vortices in turbulent...

Fox, Amanda Katherine

2012-06-07T23:59:59.000Z

306

Vortex Induced Vibrations of cylinders : experiments in reducing drag force and amplitude of motion  

E-Print Network [OSTI]

Reducing the deleterious effect of Vortex Induced Vibrations (VIV) in marine risers is an important task for ocean engineers; and many competing factors exist in the design of VIV suppression devices. This thesis explores ...

Farrell, David Emmanuel

2007-01-01T23:59:59.000Z

307

Effects of trailing edge flap dynamic deployment on blade-vortex interactions  

E-Print Network [OSTI]

A theoretical and experimental investigation is undertaken to determine the effects of an actively deployable trailing edge flap on the disturbances created during blade-vortex interactions (BVI). The theoretical model consists of an unsteady panel...

Nelson, Carter T.

2012-06-07T23:59:59.000Z

308

Steady-state and equilibrium vortex configurations, transitions, and evolution in a mesoscopic superconducting cylinder  

E-Print Network [OSTI]

that the system passes through nearly metastable intermediate configurations while seeking the final minimum-energy steady state consistent with the square symmetry of the sample. An efficient scheme to determine the equilibrium vortex configuration in a...

Kim, S.; Hu, Chia-Ren; Andrews, MJ.

2004-01-01T23:59:59.000Z

309

An adaptive mesh method for the simulation of Blade Vortex Interaction  

E-Print Network [OSTI]

An adaptive mesh method for the simulation of parallel ics. Blade Vortex Interaction (BV1) with an active Trailing Edge Flap (TEF) is presented. The two-dimensional 1111-steady problem is solved by a higher order upwind Euler method...

Kim, Kyu-Sup

2012-06-07T23:59:59.000Z

310

MEC E 638 VORTEX FLOWS Winter 2014 LARGE-SCALE STRUCTURES IN TURBULENCE PROF L. SIGURDSON  

E-Print Network [OSTI]

to find the characteristic vortex structures; to read the literature, nomenclature, terminology. TOPICS: Professor Lorenz Sigurdson, 5-1B Mech Eng Bldg, lorenz@ualberta.ca, http://websrv.mece.ualberta.ca/intranet

Flynn, Morris R.

311

Visualization of Intricate Flow Structures for Vortex Breakdown Analysis Xavier Tricoche  

E-Print Network [OSTI]

Hansen University of Utah Figure 1: Vortex breakdown bubble in numerical simulation of a cylindrical to study their impact on flight stability. Yet, to fully exploit the huge amount of information contained

Utah, University of

312

Annular Vortex Generation for Inertial Fusion Energy Beam-Line Protection  

SciTech Connect (OSTI)

The use of swirling annular vortex flow inside beam entrance tubes can protect beam-line structural materials in chambers for heavy-ion inertial fusion energy (IFE) applications. An annular wall jet, or vortex tube, is generated by injecting liquid tangent to the inner surface of a tube wall with both axially and azimuthally directed velocity components. A layer of liquid then lines the beam tube wall, which may improve the effectiveness of neutron shielding, and condenses and removes vaporized coolant that may enter the beam tubes. Vortex tubes have been constructed and tested with a thickness of three-tenths the pipe radius. Analysis of the flow is given, along with experimental examples of vortex tube fluid mechanics and an estimate of the layer thickness, based on simple mass conservation considerations.

Pemberton, Steven J.; Abbott, Ryan P.; Peterson, Per F. [University of California (United States)

2003-05-15T23:59:59.000Z

313

Dynamic Switching of the Spin Circulation in Tapered Magnetic Nanodisks  

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

Dynamic Switching of the Spin Dynamic Switching of the Spin Circulation in Tapered Magnetic Nanodisks Dynamic Switching of the Spin Circulation in Tapered Magnetic Nanodisks Print Monday, 22 April 2013 12:09 fischer-magnetic vortices Ferromagnetic NiFe disks (500-nm-wide and 20-nm-thick), were fabricated by e-beam lithography onto a waveguide structure. Field pulses, generated by launching current pulses into the waveguide trigger the magnetization dynamics in the elements. Using the soft x-ray microscope XM-1 providing 25-nm spatial resolution, circularly polarized soft x-rays give rise to XMCD contrast which allows to record an image of the in-plane circulation of the magnetic vortex. The topology of vortices-areas where there is a spinning motion around an imaginary axis-is a physical phenomenon which is found across a large

314

Effect of a surface boundary layer on an intensifying, downward-propagating vortex  

E-Print Network [OSTI]

EFFECT OF A SURFACE BOUNDARY LAYER ON AN INTENSIFYING, DOWNWARD-PROPAGATING VORTEX A Thesis by VINCENT TUNSTALL WOOD Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement for the degree of MASTER... OF SCIENCE May 1977 Major Subject: Meteorology EFFECT OF A SURFACE BOUNDARY LAYER ON AN INTENSIFYING, DOWNWARD-PROPAGATING VORTEX A Thesis by VINCENT TUNSTALL WOOD Approved as to style and content by: (Chairman of Committee) (Head of Department...

Wood, Vincent Tunstall

2012-06-07T23:59:59.000Z

315

Explicit mean-field radius for nearly parallel vortex filaments in statistical equilibrium  

E-Print Network [OSTI]

Geophysical research has focused on flows, such as ocean currents, as two dimensional. Two dimensional point or blob vortex models have the advantage of having a Hamiltonian, whereas 3D vortex filament or tube systems do not necessarily have one, although they do have action functionals. On the other hand, certain classes of 3D vortex models called nearly parallel vortex filament models do have a Hamiltonian and are more accurate descriptions of geophysical and atmospheric flows than purely 2D models, especially at smaller scales. In these ``quasi-2D'' models we replace 2D point vortices with vortex filaments that are very straight and nearly parallel but have Brownian variations along their lengths due to local self-induction. When very straight, quasi-2D filaments are expected to have virtually the same planar density distributions as 2D models. An open problem is when quasi-2D model statistics behave differently than those of the related 2D system and how this difference is manifested. In this paper we study the nearly parallel vortex filament model of Klein, Majda, Damodaran in statistical equilibrium. We are able to obtain a free-energy functional for the system in a non-extensive thermodynamic limit that is a function of the mean square vortex position $R^2$ and solve \\emph{explicitly} for $R^2$. Such an explicit formula has never been obtained for a non-2D model. We compare the results of our formula to a 2-D formula of \\cite{Lim:2005} and show qualitatively different behavior even when we disallow vortex braiding. We further confirm our results using Path Integral Monte Carlo (Ceperley (1995)) \\emph{without} permutations and that the Klein, Majda, Damodaran model's asymptotic assumptions \\emph{are valid} for parameters where these deviations occur.

Timothy D. Andersen; Chjan C. Lim

2006-11-19T23:59:59.000Z

316

Magnetism in Thiolated Gold Model Junctions  

Science Journals Connector (OSTI)

Magnetism in Thiolated Gold Model Junctions ... Nanoparticles revealing magnetism and their assemblies are of importance in nanotechnology and spintronics,(26, 27) in fundamental quantum-mechanical experiments,(28) and potentially in quantum computing. ... (47) Even though the magnetism has not yet been explicitly demonstrated in pure, neutral, and small thiolated AuNPs, it may be readily promoted by transition-metal doping of AuNP cores. ...

Matúš Dubecký; Haibin Su

2012-07-24T23:59:59.000Z

317

RisR1425(EN) Possible magnetism in vor-  

E-Print Network [OSTI]

Risø­R­1425(EN) Possible magnetism in vor- tex cores of superconduct- ing TmNi2B2C studied by small and attracted a large attention because superconductivity and magnetic ordering are coexisting in R = Dy, Ho, Er the creation of Cooper pairs. The magnetism is of the indirect Ruderman-Kittel-Kasuya-Yosida(RKKY) type where

318

Statistical Behavior of Formation Process of Magnetic Vortex State in Ni80Fe20 Nanodisks  

E-Print Network [OSTI]

This work was supported by the Director, Office of Science,Office of Basic Energy Sciences, Materials Sciences and

Im, Mi-Young

2011-01-01T23:59:59.000Z

319

Magnetism.1  

Science Journals Connector (OSTI)

... each complete magnets with a pair of poles. The general character of the earth's magnetism has long been known—that the earth behaves with regard to magnets as though it ... and that these poles have a slow secular motion. For many years the earth's magnetism has been the subject of careful study by the most powerful minds. Gauss organized ...

1890-01-16T23:59:59.000Z

320

Numerical simulation of a viscous vortex ring interaction with a density interface  

SciTech Connect (OSTI)

When a vortex-dominated flow interacts with a sharp density interface, the dynamics are characterized by the interaction of baroclinically generated vorticity with the already existing vorticity field. This can be seen in many natural and technology settings; examples are the interaction of a ship or submarine wake with a thermocline, the collision of a buoyant thermal with a temperature inversion, and the interaction of a vortex flow with a flame front. This problem also serves as a generic model for turbulent mixing and entrainment processes across sharp density interfaces. The interaction between vortices and a free surface, with corresponds to the case where the density jump is very large, has been studied fairly extensively, both experimentally and computationally. By comparison, the literature for the more general case of vortex pairs and rings interacting with sharp density interfaces is relatively sparse. Experiments and numerical studies have been performed, but the numerical simulations were confined primarily to vortex pairs, restricted to the inviscid case, and the effect of density variation modeled under the Boussinesq approximation. The experiments were also confined to the Boussinesq regime. In this paper, we study the motion of a vortex ring in a sharply stratified, viscous fluid via a numerical solution of the full Navier-Stokes equations with finite-amplitude density variation. both Boussinesq and non-Boussinesq flow regimes will be studied, the effect of viscosity on the interaction will be examined, and three-dimensional aspects of the motion will be addressed, such as Widnall instability of the vortex ring and vortex reconnection at the interface.

Marcus, D.L.; Bell, J.B.

1990-10-01T23:59:59.000Z

Note: This page contains sample records for the topic "magnetic vortex core" 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

Vortex Dynamics for the Ginzburg-Landau-Schrödinger Equation  

E-Print Network [OSTI]

The initial value problem for the Ginzburg-Landau-Schr\\"odinger equation is examined in the $\\epsilon \\rightarrow 0$ limit under two main assumptions on the initial data $\\phi^\\epsilon$. The first assumption is that $\\phi^\\epsilon$ exhibits $m$ distinct vortices of degree $\\pm 1$; these are described as points of concentration of the Jacobian $[J\\phi^\\epsilon]$ of $\\phi^\\epsilon$. Second, we assume energy bounds consistent with vortices at the points of concentration. Under these assumptions, we identify ``vortex structures'' in the $\\epsilon \\rightarrow 0$ limit of $\\phi^\\epsilon$ and show that these structures persist in the solution $u^\\epsilon(t)$ of $GLS_\\epsilon$. We derive ordinary differential equations which govern the motion of the vortices in the $\\epsilon \\rightarrow 0$ limit. The limiting system of ordinary differential equations is a Hamitonian flow governed by the renormalized energy of Bethuel, Brezis and H\\'elein. Our arguments rely on results about the structural stability of vortices which are proved in a separate paper.

James Ellis Colliander; Robert L. Jerrard

1997-12-12T23:59:59.000Z

322

Earth’s magnetism  

Science Journals Connector (OSTI)

Earth’s magnetism, geomagnetism, terrestrial magnetism [The magnetism of the Earth] ? Erdmagnetismus m, Geomagnetismus

2014-08-01T23:59:59.000Z

323

LANGEVIN DYNAMICS OF THE TWO STAGE MELTING TRANSITION OF VORTEX MATTER IN Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}} IN THE PRESENCE OF STRAIGHT AND OF TILTED COLUMNAR DEFECTS  

SciTech Connect (OSTI)

In this paper we use London Langevin molecular dynamics simulations to investigate the vortex matter melting transition in the highly anisotropic high-temperature superconductor material Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}}#14; in the presence of low concentration of columnar defects (CDs). We reproduce with further details our previous results obtained by using Multilevel Monte Carlo simulations that showed that the melting of the nanocrystalline vortex matter occurs in two stages: a first stage melting into nanoliquid vortex matter and a second stage delocalization transition into a homogeneous liquid. Furthermore, we report on new dynamical measurements in the presence of a current that identifies clearly the irreversibility line and the second stage delocalization transition. In addition to CDs aligned along the c-axis we also simulate the case of tilted CDs which are aligned at an angle with respect to the applied magnetic field. Results for CDs tilted by 45{degree} with respect to c-axis show that the locations of the melting and delocalization transitions are not affected by the tilt when the ratio of flux lines to CDs remains constant. On the other hand we argue that some dynamical properties and in particular the position of the irreversibility line should be affected.

GOLDSCHMIDT, YADIN Y.; LIU, Jin-Tao

2007-08-07T23:59:59.000Z

324

Microsoft Word - IronCore  

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

November/December 2013 November/December 2013 Percolation Explains How Earth's Iron Core Formed The formation of Earth's metallic core, which makes up a third of our planet's mass, represents the most significant differentiation event in Earth's history. Earth's present layered structure with a metallic core and an overlying silicate mantle would have required mechanisms to separate iron alloy from a silicate phase. Percolation of liquid iron alloy moving through a solid silicate matrix (much as water percolates through porous rock, or even coffee grinds) has been proposed as a possible model for core formation (Figure 1). Many previous experimental results have ruled out percolation as a major core formation mechanism for Earth at the relatively lower pressure conditions in the upper mantle, but

325

Increasing liquid hydrocarbon recovery from natural gas: Evaluation of the vortex-tube device  

SciTech Connect (OSTI)

The vortex-tube device provides a useful addition to the range of equipment available to the gas industry. It has been shown that the use of vortex-tube equipment permits improved separation in comparison with a Joule-Thomson system, without entering into the cost and complexity of a true isentropic system such as a turbo-expander unit. The comparative advantage of the vortex tube depends upon the inlet conditions of the gas and the pressure drop that is available. An optimum pressure drop of 25--35% of the inlet gas pressure has been confirmed in practice. Although not yet tested on operating plant, it is expected that a loss of performance of vortex-tube units will occur for inlet liquid-to-gas ratios of greater than 20%. Units with up to 5% liquid at the inlet have been successfully operated showing that a single phase gas at the unit inlet is not essential. It is expected that future application of vortex tube units will be concentrated where performance improvements over Joule-Thomson units, at low capital cost, are required.

Hajdik, B. [CBS Engineering, Houston, TX (United States); Steinle, J. [BEB Erdoel and Erdgas GmbH, Hannover (Germany); Lorey, M. [Filtan Analgenbau GmbH, Langenselbold (Germany); Thomas, K. [Falk and Thomas Engineering GmbH, Wettenberg (Germany)

1997-12-31T23:59:59.000Z

326

MHD Simulations of Core Collapse Supernovae with Cosmos++  

E-Print Network [OSTI]

We performed 2D, axisymmetric, MHD simulations with Cosmos++ in order to examine the growth of the magnetorotational instability (MRI) in core--collapse supernovae. We have initialized a non--rotating 15 solar mass progenitor, infused with differential rotation and poloidal magnetic fields. The collapse of the iron core is simulated with the Shen EOS, and the parametric Ye and entropy evolution. The wavelength of the unstable mode in the post--collapse environment is expected to be only ~ 200 m. In order to achieve the fine spatial resolution requirement, we employed remapping technique after the iron core has collapsed and bounced. The MRI unstable region appears near the equator and angular momentum and entropy are transported outward. Higher resolution remap run display more vigorous overturns and stronger transport of angular momentum and entropy. Our results are in agreement with the earlier work by Akiyama et al. (2003) and Obergaulinger et al. (2009).

Akiyama, Shizuka

2010-01-01T23:59:59.000Z

327

Beamed Core Antimatter Propulsion: Engine Design and Optimization  

E-Print Network [OSTI]

A conceptual design for beamed core antimatter propulsion is reported, where electrically charged annihilation products directly generate thrust after being deflected and collimated by a magnetic nozzle. Simulations were carried out using the Geant4 (Geometry and tracking) software toolkit released by the CERN accelerator laboratory for Monte Carlo simulation of the interaction of particles with matter and fields. Geant permits a more sophisticated and comprehensive design and optimization of antimatter engines than the software environment for simulations reported by prior researchers. The main finding is that effective exhaust speeds Ve ~ 0.69c (where c is the speed of light) are feasible for charged pions in beamed core propulsion, a major improvement over the Ve ~ 0.33c estimate based on prior simulations. The improvement resulted from optimization of the geometry and the field configuration of the magnetic nozzle. Moreover, this improved performance is realized using a magnetic field on the order of 10 T at the location of its highest magnitude. Such a field could be produced with today's technology, whereas prior nozzle designs anticipated and required major advances in this area. The paper also briefly reviews prospects for production of the fuel needed for a beamed core engine.

Ronan Keane; Wei-Ming Zhang

2012-05-16T23:59:59.000Z

328

Effects of Combustion-Induced Vortex Breakdown on Flashback Limits of Syngas-Fueled Gas Turbine Combustors  

SciTech Connect (OSTI)

Turbine combustors of advanced power systems have goals to achieve very low pollutants emissions, fuel variability, and fuel flexibility. Future generation gas turbine combustors should tolerate fuel compositions ranging from natural gas to a broad range of syngas without sacrificing operational advantages and low emission characteristics. Additionally, current designs of advanced turbine combustors use various degrees of swirl and lean premixing for stabilizing flames and controlling high temperature NOx formation zones. However, issues of fuel variability and NOx control through premixing also bring a number of concerns, especially combustor flashback and flame blowout. Flashback is a combustion condition at which the flame propagates upstream against the gas stream into the burner tube. Flashback is a critical issue for premixed combustor designs, because it not only causes serious hardware damages but also increases pollutant emissions. In swirl stabilized lean premixed turbine combustors onset of flashback may occur due to (i) boundary layer flame propagation (critical velocity gradient), (ii) turbulent flame propagation in core flow, (iii) combustion instabilities, and (iv) upstream flame propagation induced by combustion induced vortex breakdown (CIVB). Flashback due to first two foregoing mechanisms is a topic of classical interest and has been studied extensively. Generally, analytical theories and experimental determinations of laminar and turbulent burning velocities model these mechanisms with sufficient precision for design usages. However, the swirling flow complicates the flashback processes in premixed combustions and the first two mechanisms inadequately describe the flashback propensity of most practical combustor designs. The presence of hydrogen in syngas significantly increases the potential for flashback. Due to high laminar burning velocity and low lean flammability limit, hydrogen tends to shift the combustor operating conditions towards flashback regime. Even a small amount of hydrogen in a fuel blend triggers the onset of flashback by altering the kinetics and thermophysical characteristics of the mixture. Additionally, the presence of hydrogen in the fuel mixture modifies the response of the flame to the global effects of stretch and preferential diffusion. Despite its immense importance in fuel flexible combustor design, little is known about the magnitude of fuel effects on CIVB induced flashback mechanism. Hence, this project investigates the effects of syngas compositions on flashback resulting from combustion induced vortex breakdown. The project uses controlled experiments and parametric modeling to understand the velocity field and flame interaction leading to CIVB driven flashback.

Ahsan Choudhuri

2011-03-31T23:59:59.000Z

329

Joule heating induced by vortex motion in a type-II superconductor Z. L. Xiao and E. Y. Andrei  

E-Print Network [OSTI]

Joule heating induced by vortex motion in a type-II superconductor Z. L. Xiao and E. Y. Andrei-II superconductor due to Joule heating induced by vortex motion. The effect of Joule heating is detected s duration, where the Joule heating is negligible and saturates, respectively. The thermometry is based

Andrei, Eva Y.

330

Method for the assessment of airborne off-target pesticide spray concentrations due to aircraft wing-tip vortex  

E-Print Network [OSTI]

that spherical spray droplets are transported by a two dimensional parametric representation of a spray-engulfing aircraft wing-tip vortex pair. Two distinctive flow regions were considered for the spray-vortex dynamics. The first occurs in the vicinity...

Oliva, Sergio Eduardo

2012-06-07T23:59:59.000Z

331

Counter-rotating vortex patches in shear: a model of the effect of wind shear on aircraft trailing vortices  

Science Journals Connector (OSTI)

...significantly a following passenger-containing aircraft and cause an accident. For example, the vortex wake of a Boeing 747 can rotate a Boeing 737 through 45 . This problem is called the trailing-vortex hazard, and since the trailing vortices can...

2002-01-01T23:59:59.000Z

332

Slowing of vortex rings by development of Kelvin waves Robert E. Hershberger, Diogo Bolster, and Russell J. Donnelly*  

E-Print Network [OSTI]

of existence, their duration a problem of stability and if there are several we have a problem of vortex mecha- nism is that the bubble loses impulse as the radius of the ring grows due to viscous decay of circulation 6 . A further theory suggests that the vortex bubble the ambient fluid car- ried along

Bolster, Diogo

333

THE COLLAPSE OF TURBULENT CORES AND RECONNECTION DIFFUSION  

SciTech Connect (OSTI)

In order for a molecular cloud clump to form stars, some transport of magnetic flux is required from the denser internal regions to the outer regions; otherwise, this can prevent the gravitational collapse. Fast magnetic reconnection, which takes place in the presence of turbulence, can induce a process of reconnection diffusion that has been elaborated on in earlier theoretical works. We have named this process turbulent reconnection diffusion, or simply RD. This paper continues our numerical study of this process and its implications. In particular, we extend our studies of RD in cylindrical clouds and consider more realistic clouds with spherical gravitational potentials (from embedded stars); we also account for the effects of the gas self-gravity. We demonstrate that, within our setup reconnection, diffusion is efficient. We have also identified the conditions under which RD becomes strong enough to make an initially subcritical cloud clump supercritical and induce its collapse. Our results indicate that the formation of a supercritical core is regulated by a complex interplay between gravity, self-gravity, the magnetic field strength, and nearly transonic and trans-Alfvénic turbulence; therefore, it is very sensitive to the initial conditions of the system. In particular, self-gravity helps RD and, as a result, the magnetic field decoupling from the collapsing gas becomes more efficient compared with the case of an external gravitational field. Our simulations confirm that RD can transport magnetic flux from the core of collapsing clumps to the envelope, but only a few of them become nearly critical or supercritical sub-Alfvénic cores, which is consistent with the observations. Furthermore, we have found that the supercritical cores built up in our simulations develop a predominantly helical magnetic field geometry that is also consistent with recent observations. Finally, we have also evaluated the effective values of the turbulent RD coefficient in our simulations and found that they are much larger than the numerical diffusion coefficient, especially for initially trans-Alfvénic clouds, thus ensuring that the detected magnetic flux removal is due to the action of turbulent RD rather than numerical diffusivity.

Leão, M. R. M.; De Gouveia Dal Pino, E. M.; Santos-Lima, R. [Instituto de Astronomia, Geofísica e Ciências Atmosféricas, Universidade de São Paulo, R. do Matão, 1226, São Paulo, SP 05508-090 (Brazil); Lazarian, A., E-mail: mleao@ime.unicamp.br, E-mail: dalpino@astro.iag.usp.br, E-mail: rlima@astro.iag.usp.br, E-mail: alazarian@facstaff.wisc.edu [Department of Astronomy, University of Wisconsin, Madison, WI 53706 (United States)

2013-11-01T23:59:59.000Z

334

Modern Magnetism  

Science Journals Connector (OSTI)

... BATES‘S "Modern Magnetism", first published in 1939, is widely appreciated as a general survey in which ... grateful to the author for collecting together so much interesting information about recent work in magnetism. ...

E. C. S.

1948-06-05T23:59:59.000Z

335

Reduction of vortex induced forces and motion through surface roughness control  

DOE Patents [OSTI]

Roughness is added to the surface of a bluff body in a relative motion with respect to a fluid. The amount, size, and distribution of roughness on the body surface is controlled passively or actively to modify the flow around the body and subsequently the Vortex Induced Forces and Motion (VIFM). The added roughness, when designed and implemented appropriately, affects in a predetermined way the boundary layer, the separation of the boundary layer, the level of turbulence, the wake, the drag and lift forces, and consequently the Vortex Induced Motion (VIM), and the fluid-structure interaction. The goal of surface roughness control is to decrease/suppress Vortex Induced Forces and Motion. Suppression is required when fluid-structure interaction becomes destructive as in VIM of flexible cylinders or rigid cylinders on elastic support, such as underwater pipelines, marine risers, tubes in heat exchangers, nuclear fuel rods, cooling towers, SPAR offshore platforms.

Bernitsas, Michael M; Raghavan, Kamaldev

2014-04-01T23:59:59.000Z

336

Experimental study of vortex generators effects on low Reynolds number airfoils in turbulent flow  

Science Journals Connector (OSTI)

In the present work, we study the aerodynamic effects of triangular vortex generators, as passive flow control devices, placed on the upper surface of an airfoil submitted to a low Reynolds number turbulent flow. In the experiments, different configurations of those devices have been studied. An Eppler 387 airfoil was used. The tests were performed in a turbulent boundary layer wind tunnel using a two component aerodynamic balance and flow visualisation systems. Turbulent flow characterisation was made by means of hot wire anemometry. Calculations of local turbulent intensity as well as temporal and spatial turbulent scales were made. Vortex generators were located at 10% and 20% of the airfoil chord from the leading edge, modifying its angle of incidence refereed to the free stream. The results show changes in the aerodynamic section coefficients, C1, Cd and C1, for the different vortex generator configurations. Neither hysteresis effects, nor leading edge bubbles were found in the experiments.

Juan Sebastián Delnero; Julio Marañon Di Leo; Mauricio Ezequiel Camocardi; Mariano A. Martinez; Jorge L. Colman Lerner

2012-01-01T23:59:59.000Z

337

Exchange-Spring Magnets: Nanocomposite Exchange-Spring Magnets for Motor and Generator Applications  

SciTech Connect (OSTI)

REACT Project: ANL will develop a cost-effective exchange-spring magnet to use in the electric motors of wind generators and EVs that uses no rare earth materials. This ANL exchange-spring magnet combines a hard magnetic outer shell with a soft magnetic inner core—coupling these together increases the performance (energy density and operating temperature). The hard and soft magnet composite particles would be created at the molecular level, followed by consolidation in a magnetic field. This process allows the particles to be oriented to maximize the magnetic properties of low-cost and abundant metals, eliminating the need for expensive imported rare earths. The ultimate goal of this project is to demonstrate this new type of magnet in a prototype electric motor.

None

2012-01-01T23:59:59.000Z

338

Topics: Discovering the lower limit to magnetic transport - MST...  

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

RFP plasmas has long been thought to result from parallel losses on stochastic magnetic field lines that wander from the core to the edge. The low safety factor in the RFP permits...

339

Novel vortex dynamics in untwinned YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} single crystals  

SciTech Connect (OSTI)

Magnetotransport measurements on a clean, untwinned YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} single crystal show that the vortex dynamics at temperatures just below the vortex lattice melting transition are highly dependent on the type of modulation of the probing current. While in the case of DC current the flux flow is disordered, the {open_quotes}shaking{close_quotes} of the vortex lattice by a square-wave current leads to a more uniform vortex motion. A small asymmetry ({approximately}10%) in the durations of the positive and negative parts of the square-wave period induces periodical oscillations of the voltage response amplitude. The period of oscillations ({approximately}100 s) is the same order of magnitude as the time needed for vortices to cross the sample (transit time). The authors relate the observed voltage oscillations to a periodically ordered vortex motion.

Gordeev, S.N.; Oussena, M.; Pinfold, S.; Langan, R.M. [Univ. of Southampton (United Kingdom)] [and others

1996-12-01T23:59:59.000Z

340

Migratory magnetism  

Science Journals Connector (OSTI)

... in tune with the Earth's magnetic field. But how, exactly, do creatures sense magnetism? This is one of the most intriguing questions in modern biology - and also ... move preferentially in a north-south direction. This finding hints at the possible influence of magnetism on their movements. ...

Henry Gee

1999-10-06T23:59:59.000Z

Note: This page contains sample records for the topic "magnetic vortex core" 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

Phase-locking of driven vortex lattices with transverse ac force and periodic pinning  

SciTech Connect (OSTI)

For a vortex lattice moving in a periodic array we show analytically and numerically that a new type of phase locking occurs in the presence of a longitudinal dc driving force and a transverse ac driving force. This phase locking is distinct from the Shapiro step phase locking found with longitudinal ac drives. We show that an increase in critical current and a fundamental phase-locked step width scale with the square of the driving ac amplitude. Our results should carry over to other systems such as vortex motion in Josephson-junction arrays.

Reichhardt, Charles; Kolton, Alejandro B.; Dominguez, Daniel; Gronbech-Jensen, Niels

2001-10-01T23:59:59.000Z

342

The effects of a jet on vortex breakdown over a sharp leading-edge delta wing  

E-Print Network [OSTI]

THE EFFECTS OF A JET ON VORTEX BREAKDOWN OVER A SHARP LEADING-EDGE DELTA WING A Thesis Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE December 1985... Major Subject: Aerospace Engineering THE EFFECTS OF A JET ON VORTEX BREAKDOWN OVER A SHARP LEADING-EDGE DELTA WING A Thesis by IAN KENNETH MAYNARD Approved as to style and content by: Cyrus Ostowar (Chairman of Committee) Stan J Miley (M er...

Maynard, Ian Kenneth

2012-06-07T23:59:59.000Z

343

Simulation of systematic errors in the SLC magnets  

SciTech Connect (OSTI)

The distance (iron to iron) between a focusing and a defocusing magnet in the SLC-arcs is 6.7056 cm and the iron length of each of them is 2.52914 m. To represent these magnets by a hard-edge model in computer codes TRANSPORT or TURTLE the magnetic length rather than the core length of these magnets is of interest. In the present lattice the magnetic length for the field and the gradient of each of these magnets is assumed to be 2.5462 m.

Jaeger, J.

1983-08-08T23:59:59.000Z

344

Magnetic Testing of Bonded Magnets  

Science Journals Connector (OSTI)

Many techniques exist to characterize the magnetic properties of bonded magnets. We will review the common and not so common techniques in use, with emphasis on the advantages and disadvantages of each one, an...

S. R. Trout

2003-01-01T23:59:59.000Z

345

Verification of Ni magnetic moment in GdNi2 Laves phase by magnetic circular dichroism measurement  

Science Journals Connector (OSTI)

Investigation of the magnetic moment of nickel in the polycrystal GdNi2 Laves phase was carried out by means of magnetic circular dichroism (MCD) in the core-level x-ray-absorption spectroscopy. It was revealed that the nickel magnetic moment originating from the 3d state (band) does exist and couples antiparallel to that of gadolinium whose MCD was observed at the M4,5 absorption edge. That is, nickel retains an intrinsic magnetic moment even in the Laves phase concentration. Furthermore, by analyzing in terms of sum rule, the contribution of spin and orbital magnetic moments to the magnetic moment was evaluated and discussed.

M. Mizumaki; K. Yano; I. Umehara; F. Ishikawa; K. Sato; A. Koizumi; N. Sakai; T. Muro

2003-04-09T23:59:59.000Z

346

Alkali solution treatment on sandstone cores  

E-Print Network [OSTI]

was used for filtering the solution before the injection into the core. Hassler-t e Core Holder A stainless steel core holder was used to hold the core for treatment with the solutions. The core sample was positioned in the center of the core holder... and heat the water in the flask. Electric Heatin Ta e A silicone rubber embedded flexible heating tape was used to wrap the core holder to heat the core sample to the desired temperature. The maximum 0 continuous operating temperature of the tape...

Lee, Suk Jin

2012-06-07T23:59:59.000Z

347

Permanent-magnet-less machine having an enclosed air gap  

DOE Patents [OSTI]

A permanent magnet-less, brushless synchronous system includes a stator that generates a magnetic rotating field when sourced by an alternating current. An uncluttered rotor disposed within the magnetic rotating field is spaced apart from the stator to form an air gap relative to an axis of rotation. A stationary excitation core spaced apart from the uncluttered rotor by an axial air gap and a radial air gap substantially encloses the stationary excitation core. Some permanent magnet-less, brushless synchronous systems include stator core gaps to reduce axial flux flow. Some permanent magnet-less, brushless synchronous systems include an uncluttered rotor coupled to outer laminations. The quadrature-axis inductance may be increased in some synchronous systems. Some synchronous systems convert energy such as mechanical energy into electrical energy (e.g., a generator); other synchronous systems may convert any form of energy into mechanical energy (e.g., a motor).

Hsu, John S. (Oak Ridge, TN)

2012-02-07T23:59:59.000Z

348

EARLY STAGES OF CLUSTER FORMATION: FRAGMENTATION OF MASSIVE DENSE CORES DOWN TO {approx}< 1000 AU  

SciTech Connect (OSTI)

In order to study the fragmentation of massive dense cores, which constitute the cluster cradles, we observed the continuum at 1.3 mm and the CO (2-1) emission of four massive cores with the Plateau de Bure Interferometer in the most extended configuration. We detected dust condensations down to {approx}0.3 M {sub Sun} and separate millimeter sources down to 0.''4 or {approx}< 1000 AU, comparable to the sensitivities and separations reached in optical/infrared studies of clusters. The CO (2-1) high angular resolution images reveal high-velocity knots usually aligned with previously known outflow directions. This, in combination with additional cores from the literature observed at similar mass sensitivity and spatial resolution, allowed us to build a sample of 18 protoclusters with luminosities spanning three orders of magnitude. Among the 18 regions, {approx}30% show no signs of fragmentation, while 50% split up into {approx}> 4 millimeter sources. We compiled a list of properties for the 18 massive dense cores, such as bolometric luminosity, total mass, and mean density, and found no correlation of any of these parameters with the fragmentation level. In order to investigate the combined effects of the magnetic field, radiative feedback, and turbulence in the fragmentation process, we compared our observations to radiation magnetohydrodynamic simulations and found that the low-fragmented regions are reproduced well in the magnetized core case, while the highly fragmented regions are consistent with cores where turbulence dominates over the magnetic field. Overall, our study suggests that the fragmentation in massive dense cores could be determined by the initial magnetic field/turbulence balance in each particular core.

Palau, Aina; Girart, Josep M. [Institut de Ciencies de l'Espai (CSIC-IEEC), Campus UAB-Facultat de Ciencies, Torre C5-parell 2, E-08193 Bellaterra, Catalunya (Spain)] [Institut de Ciencies de l'Espai (CSIC-IEEC), Campus UAB-Facultat de Ciencies, Torre C5-parell 2, E-08193 Bellaterra, Catalunya (Spain); Fuente, Asuncion [Observatorio Astronomico Nacional, P.O. Box 112, E-28803 Alcala de Henares, Madrid (Spain)] [Observatorio Astronomico Nacional, P.O. Box 112, E-28803 Alcala de Henares, Madrid (Spain); Estalella, Robert [Departament d'Astronomia i Meteorologia (IEEC-UB), Institut de Ciencies del Cosmos, Universitat de Barcelona, Marti Franques, 1, E-08028 Barcelona (Spain)] [Departament d'Astronomia i Meteorologia (IEEC-UB), Institut de Ciencies del Cosmos, Universitat de Barcelona, Marti Franques, 1, E-08028 Barcelona (Spain); Ho, Paul T. P.; Zhang, Qizhou [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)] [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Sanchez-Monge, Alvaro; Fontani, Francesco; Cesaroni, Riccardo [Osservatorio Astrofisico di Arcetri, INAF, Lago E. Fermi 5, I-50125 Firenze (Italy)] [Osservatorio Astrofisico di Arcetri, INAF, Lago E. Fermi 5, I-50125 Firenze (Italy); Busquet, Gemma [INAF-Istituto di Astrofisica e Planetologia Spaziali, Area di Recerca di Tor Vergata, Via Fosso Cavaliere 100, I-00133 Roma (Italy)] [INAF-Istituto di Astrofisica e Planetologia Spaziali, Area di Recerca di Tor Vergata, Via Fosso Cavaliere 100, I-00133 Roma (Italy); Commercon, Benoit; Hennebelle, Patrick [Laboratoire de Radioastronomie, UMR CNRS 8112, Ecole Normale Superieure et Observatoire de Paris, 24 rue Lhomond, F-75231 Paris Cedex 05 (France)] [Laboratoire de Radioastronomie, UMR CNRS 8112, Ecole Normale Superieure et Observatoire de Paris, 24 rue Lhomond, F-75231 Paris Cedex 05 (France); Boissier, Jeremie [Istituto di Radioastronomia, INAF, Via Gobetti 101, I-40129 Bologna (Italy)] [Istituto di Radioastronomia, INAF, Via Gobetti 101, I-40129 Bologna (Italy); Zapata, Luis A., E-mail: palau@ieec.uab.es [Centro de Radioastronomia y Astrofisica, Universidad Nacional Autonoma de Mexico, P.O. Box 3-72, 58090 Morelia, Michoacan (Mexico)

2013-01-10T23:59:59.000Z

349

Tropical cyclone genesis efficiency: mid-level versus bottom vortex Xuyang Ge and Tim Li  

E-Print Network [OSTI]

;4 1. Introduction Tropical cyclone (TC) genesis is the least understood phase in a TC life cycle is cyclogenesis in an environment with a mid-level vortex (EMV). An analysis of the WNP TC genesis in 2000 the QuikSCAT-derived surface wind observations, there was no sign

Li, Tim

350

DETECTION OF VORTEX TUBES IN SOLAR GRANULATION FROM OBSERVATIONS WITH SUNRISE  

SciTech Connect (OSTI)

We have investigated a time series of continuum intensity maps and corresponding Dopplergrams of granulation in a very quiet solar region at the disk center, recorded with the Imaging Magnetograph eXperiment (IMaX) on board the balloon-borne solar observatory SUNRISE. We find that granules frequently show substructure in the form of lanes composed of a leading bright rim and a trailing dark edge, which move together from the boundary of a granule into the granule itself. We find strikingly similar events in synthesized intensity maps from an ab initio numerical simulation of solar surface convection. From cross sections through the computational domain of the simulation, we conclude that these granular lanes are the visible signature of (horizontally oriented) vortex tubes. The characteristic optical appearance of vortex tubes at the solar surface is explained. We propose that the observed vortex tubes may represent only the large-scale end of a hierarchy of vortex tubes existing near the solar surface.

Steiner, O.; Franz, M.; Bello Gonzalez, N.; Nutto, Ch.; Rezaei, R.; Schmidt, W. [Kiepenheuer-Institut fuer Sonnenphysik, Schoeneckstrasse 6, 79104 Freiburg (Germany); Martinez Pillet, V.; Bonet Navarro, J. A. [Instituto de Astrofisica de Canarias, 38200, La Laguna, Tenerife (Spain); Del Toro Iniesta, J. C. [Instituto de Astrofisica de Andalucia (CSIC), Apdo. de Correos 3004, 18080 Granada (Spain); Domingo, V. [Grupo de Astronomia y Ciencias del Espacio, Universidad de Valencia, 46980 Paterna, Valencia (Spain); Solanki, S. K.; Barthol, P.; Gandorfer, A. [Max-Planck-Institut fuer Sonnensystemforschung, 37191 Katlenburg-Lindau (Germany); Knoelker, M., E-mail: steiner@kis.uni-freiburg.d [High Altitude Observatory, National Center for Atmospheric Research (NCAR), Boulder, CO 80307-3000 (United States)

2010-11-10T23:59:59.000Z

351

ADVANCES IN ATMOSPHERIC SCIENCES, VOL. 27, NO. 2, 2010, 243252 Mesoscale Barotropic Instability of Vortex Rossby  

E-Print Network [OSTI]

ADVANCES IN ATMOSPHERIC SCIENCES, VOL. 27, NO. 2, 2010, 243­252 Mesoscale Barotropic Instability of Vortex Rossby Waves in Tropical Cyclones ZHONG Wei1 ( Í), LU Han-Cheng1 (ö ), and Da-Lin ZHANG2 1 Institute of Meteorology, PLA University of Science and Technology, Nanjing 211101 2 Department

Zhang, Da-Lin

352

Sediment resuspension and erosion by vortex rings R. J. Munro,1,a  

E-Print Network [OSTI]

Sediment resuspension and erosion by vortex rings R. J. Munro,1,a N. Bethke,2 and S. B. Dalziel2 1; accepted 26 January 2009; published online 8 April 2009 Particle resuspension and erosion induced-ring propagation speed. The critical conditions for resuspension whereby particles are only just resuspended were

Dalziel, Stuart

353

Particle resuspension by an impacting vortex ring RICK J. MUNRO & STUART B. DALZIEL  

E-Print Network [OSTI]

Particle resuspension by an impacting vortex ring RICK J. MUNRO & STUART B. DALZIEL Department results from a set of visualization experiments conducted to analyse the hydrodynamic resuspension of particles from a thick horizontal sediment layer. The mechanism employed to produce the resuspension

Dalziel, Stuart

354

Vortex Ring Interaction with a Particle Layer: Implications for Sediment Transport  

E-Print Network [OSTI]

resuspension has been studied much less. This is an important mechanism, however, as it represents an integral conducted to study particle resuspension by vortex rings colliding with a particle bed. The dynamics at the resuspension onset are investigated, showing that the deformable particle bed resembles a free slip boundary

Dalziel, Stuart

355

Resuspension onset and crater erosion by a vortex ring interacting with a particle layer  

Science Journals Connector (OSTI)

This paper presents results from an experimental investigation of the interaction of a vortex ring with a particle layer. The flowdynamics during the onset of particle resuspension are analysed using particle image velocimetry while a light attenuation method provides accurate measurements of the final eroded crater shape. This work is a continuation of the research described in R. J. Munro N. Bethke and S. B. Dalziel “Sediment resuspension and erosion by vortex rings ” Phys. Fluids21 046601 (2009)10.1063/1.3083318 which focussed on the general resuspension onset dynamics and initial crater formation. Here we analyse the velocity induced by the vortex ring on the particle layer surface during the resuspension of particles for different particle sizes and the shape and size of the final craters that are formed by the impact of the vortex ring. We find that the boundary condition is characterised by a quasi-slip velocity at the particle layer surface independent of the particle size. The particle diameter and thus bed permeability is found to have a significant effect on the final crater characteristics.

N. Bethke; S. B. Dalziel

2012-01-01T23:59:59.000Z

356

Resuspension onset and crater erosion by a vortex ring interacting with a particle layer  

E-Print Network [OSTI]

Resuspension onset and crater erosion by a vortex ring interacting with a particle layer N. Bethke://pof.aip.org/features/most_downloaded Information for Authors: http://pof.aip.org/authors #12;PHYSICS OF FLUIDS 24, 063301 (2012) Resuspension onset layer. The flow dynamics during the onset of particle resuspension are analysed using particle image

Dalziel, Stuart

357

Tip Vortex Field Resolution Using an Adaptive Dual-Mesh Computational Nathan Hariharan  

E-Print Network [OSTI]

for the aforementioned unsteady, vortical fields. 1. Introduction 1.1 Background Vortical wakes introduce important AMR in an unstructured Euler solver. Potsdam[3] also applied unstructured AMR to wind turbine wake1 Tip Vortex Field Resolution Using an Adaptive Dual-Mesh Computational Paradigm Nathan Hariharan

Steffen, Michael

358

First-order disorder-driven transition and inverse melting of the vortex lattice  

E-Print Network [OSTI]

`inverse' melting behavior. � 2001 Published by Elsevier Science B.V. Keywords: Type-II superconductivity-order transition (FOT) [1±5] whereas at low temperatures the ordered vortex lattice transforms into a disordered open questions in the phase diagram of HTS is the thermodynamic nature of the disorder-dri- ven

Zeldov, Eli

359

Computational Analysis of a Tip Vortex Structure Shed from a Bioinspired Blade  

E-Print Network [OSTI]

design for this purpose. Different rotor blade designs and relevant insect wings are under study Computational Analysis of a Tip Vortex Structure Shed from a Bioinspired Blade Sebastian was generated with SolidWorks CAD software from measurements performed on a wing sample obtained from

Maccabe, Barney

360

VIVDR -Vortex-induced vibration data repository An overview of available riser datasets  

E-Print Network [OSTI]

VIVDR - Vortex-induced vibration data repository An overview of available riser datasets http://oe.mit.edu/VIV H. Mukundan and M. Triantafyllou 20 April 2008 #12;NDP 38m long riser model datasets #12;33 q Rig q Tension applied through spring-supported clump weights NDP 38m long riser model datasets

Note: This page contains sample records for the topic "magnetic vortex core" 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

2094 OPTICS LETTERS / Vol. 28, No. 21 / November 1, 2003 Fundamental and vortex solitons in a  

E-Print Network [OSTI]

2094 OPTICS LETTERS / Vol. 28, No. 21 / November 1, 2003 Fundamental and vortex solitons in a two-dimensional optical lattice Jianke Yang Department of Mathematics and Statistics, University of Vermont, Burlington-dimensional optically induced waveguide array are reported. In the strong localization regime the fundamental soliton

Yang, Jianke

362

Effect of asymmetric axial strain on the behavior of the juncture vortex system  

E-Print Network [OSTI]

The objective of this research was to investigate the behavior of the vortex formed in a wing-body juncture in a water tunnel flow. The wing-body juncture was created by mounting a symmetrical airfoil with an elliptical leading edge normal to a flat...

Trosper, Jeffrey Randall

2012-06-07T23:59:59.000Z

363

Nanogenerator as an active sensor for vortex capture and ambient wind-velocity detection  

E-Print Network [OSTI]

and mechanical (wind, water flow, vibration, friction and body movement) energies are common in the ambientNanogenerator as an active sensor for vortex capture and ambient wind-velocity detection Rui Zhang principle, ambient wind-speed measurements with the NG are demonstrated. Due to the simple structure, high

Wang, Zhong L.

364

Acoustic emission from magnetic flux tubes in the solar network  

E-Print Network [OSTI]

We present the results of three-dimensional numerical simulations to investigate the excitation of waves in the magnetic network of the Sun due to footpoint motions of a magnetic flux tube. We consider motions that typically mimic granular buffeting and vortex flows and implement them as driving motions at the base of the flux tube. The driving motions generates various MHD modes within the flux tube and acoustic waves in the ambient medium. The response of the upper atmosphere to the underlying photospheric motion and the role of the flux tube in channeling the waves is investigated. We compute the acoustic energy flux in the various wave modes across different boundary layers defined by the plasma and magnetic field parameters and examine the observational implications for chromospheric and coronal heating.

Vigeesh, G

2013-01-01T23:59:59.000Z

365

Core Values | Department of Energy  

Broader source: Energy.gov (indexed) [DOE]

Core Values Core Values Core Values People - People are our most important resource. We respect and use our experience and skills and appreciate our diversity. Business Excellence - We are fiscally responsible and actively pursue best business practices. Safety - We protect our human and material resources and promote safe work practices within the office and at our sites. Communication - We take full advantage of our virtual organization's strengths and share information freely across all levels of the organization. Leadership and Teamwork - We encourage leadership and teamwork at all levels of the organization. We value active participation and demonstrate respect for each other. Customer Service - We openly communicate with all our customers in a timely manner and actively seek opportunities to improve our services.

366

Synthesis and magnetic reversal of bi-conical Ni nanostructures  

SciTech Connect (OSTI)

Template synthesis in polyethylene terephthalate (PET) membranes has been used to grow hour glass shaped nickel nanowires with a constriction in the range of tens of nanometers at the center. Anisotropic magnetoresistance measurements have been performed on a single nanowire to follow magnetization reversal of the structure. The results are explained via 3D micromagnetic simulations showing the appearance of a complex vortex state close to the constriction whose propagation depends on the angle between the cone axis and the applied field. The interest of this original growth process for spintronics is discussed.

Biziere, N. [Laboratoire des Solides Irradies, CEA/CNRS/Ecole Polytechnique, Ecole Polytechnique, 91128 Palaiseau Cedex (France); CEMES-CNRS, 29 Rue Jeanne Marvig, 31055 Toulouse (France); Lassalle Ballier, R.; Viret, M. [Service de Physique de l'Etat Condense, DSM/IRAMIS/SPEC, CEA Saclay URA CNRS 2464, 91191 Gif-Sur-Yvette Cedex (France); Clochard, M. C.; Wade, T. L.; Wegrowe, J. E. [Laboratoire des Solides Irradies, CEA/CNRS/Ecole Polytechnique, Ecole Polytechnique, 91128 Palaiseau Cedex (France); Balanzat, E. [CIMAP, Unite Mixte CEA-CNRS-ENSICAEN, F-14070 Caen Cedex 5 (France)

2011-09-15T23:59:59.000Z

367

Magnetic shielding  

DOE Patents [OSTI]

A magnetically-conductive filler material bridges the gap between a multi-part magnetic shield structure which substantially encloses a predetermined volume so as to minimize the ingress or egress of magnetic fields with respect to that volume. The filler material includes a heavy concentration of single-magnetic-domain-sized particles of a magnetically conductive material (e.g. soft iron, carbon steel or the like) dispersed throughout a carrier material which is generally a non-magnetic material that is at least sometimes in a plastic or liquid state. The maximum cross-sectional particle dimension is substantially less than the nominal dimension of the gap to be filled. An epoxy base material (i.e. without any hardening additive) low volatility vacuum greases or the like may be used for the carrier material. The structure is preferably exposed to the expected ambient magnetic field while the carrier is in a plastic or liquid state so as to facilitate alignment of the single-magnetic-domain-sized particles with the expected magnetic field lines. 3 figs.

Kerns, J.A.; Stone, R.R.; Fabyan, J.

1987-10-06T23:59:59.000Z

368

Magnetic shielding  

DOE Patents [OSTI]

A magnetically-conductive filler material bridges the gap between a multi-part magnetic shield structure which substantially encloses a predetermined volume so as to minimize the ingress or egress of magnetic fields with respect to that volume. The filler material includes a heavy concentration of single-magnetic-domain-sized particles of a magnetically conductive material (e.g. soft iron, carbon steel or the like) dispersed throughout a carrier material which is generally a non-magnetic material that is at least sometimes in a plastic or liquid state. The maximum cross-sectional particle dimension is substantially less than the nominal dimension of the gap to be filled. An epoxy base material (i.e. without any hardening additive) low volatility vacuum greases or the like may be used for the carrier material. The structure is preferably exposed to the expected ambient magnetic field while the carrier is in a plastic or liquid state so as to facilitate alignment of the single-magnetic-domain-sized particles with the expected magnetic field lines.

Kerns, John A. (Livermore, CA); Stone, Roger R. (Walnut Creek, CA); Fabyan, Joseph (Livermore, CA)

1987-01-01T23:59:59.000Z

369

Strange Magnetism  

E-Print Network [OSTI]

We present an analytic and parameter-free expression for the momentum dependence of the strange magnetic form factor of the nucleon and its corresponding radius which has been derived in Heavy Baryon Chiral Perturbation Theory. We also discuss a model-independent relation between the isoscalar magnetic and the strange magnetic form factors of the nucleon based on chiral symmetry and SU(3) only. These limites are used to derive bounds on the strange magnetic moment of the proton from the recent measurement by the SAMPLE collaboration.

Thomas R. Hemmert; Ulf-G. Meissner; Sven Steininger

1998-11-09T23:59:59.000Z

370

Optical Magnetism  

Science Journals Connector (OSTI)

Magnetic dipole radiation one fourth as intense as electric dipole radiation, as well as a novel nonlinear magneto-optical effect are reported in dielectric media.

Oliveira, Samuel L; Rand, Stephen C

371

Controlled self-assembly of multiferroic core-shell nanoparticles exhibiting strong magneto-electric effects  

SciTech Connect (OSTI)

Ferromagnetic-ferroelectric composites show strain mediated coupling between the magnetic and electric sub-systems due to magnetostriction and piezoelectric effects associated with the ferroic phases. We have synthesized core-shell multiferroic nano-composites by functionalizing 10–100?nm barium titanate and nickel ferrite nanoparticles with complementary coupling groups and allowing them to self-assemble in the presence of a catalyst. The core-shell structure was confirmed by electron microscopy and magnetic force microscopy. Evidence for strong strain mediated magneto-electric coupling was obtained by static magnetic field induced variations in the permittivity over 16–18?GHz and polarization and by electric field induced by low-frequency ac magnetic fields.

Sreenivasulu, Gollapudi; Hamilton, Sean L.; Lehto, Piper R.; Srinivasan, Gopalan, E-mail: srinivas@oakland.edu [Physics Department, Oakland University, Rochester, Michigan 48309-4401 (United States); Popov, Maksym [Physics Department, Oakland University, Rochester, Michigan 48309-4401 (United States); Radiophysics Department, Taras Shevchenko National University of Kyiv, Kyiv 01601 (Ukraine); Chavez, Ferman A. [Chemistry Department, Oakland University, Rochester, Michigan 48309-4401 (United States)

2014-02-03T23:59:59.000Z

372

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

373

Definition: Core Analysis | Open Energy Information  

Open Energy Info (EERE)

Core Analysis Core Analysis Jump to: navigation, search Dictionary.png Core Analysis Core samples are obtained from drilling a well, typically using a synthetic diamond coated bit that has a hollow center so cylindrical rock samples ("core") can be extracted. Core samples successfully recovered are visually inspected to determine rock type, mineralization, and fracture networks, then certain laboratory analyses may ensue to acquire detailed rock properties. View on Wikipedia Wikipedia Definition A core sample is a cylindrical section of (usually) a naturally occurring substance. Most core samples are obtained by drilling with special drills into the substance, for example sediment or rock, with a hollow steel tube called a core drill. The hole made for the core sample is

374

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...

375

Multi-core Performance Analysis  

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

core Performance Analysis core Performance Analysis HPC Computation 1 Performance Analysis * Compiler Feedback * HWPC Data * Load Balance 2 Compiler Feedback * Before optimizing code, it's critical to know what the compiler does to your code - Loop optimizations - Vectorization - Prefetching - ... * Equally important to what the compiler does is what it doesn't do, and why - Data dependencies - Misplaced branches - Unknown loop counts - ... 3 Enabling Compiler Feedback * Portland Group - Minfo=all - Mneginfo - Minfo=ccff (Common Compiler Feedback Format) * Cray - rm (Fortran) - hlist=m (C/C++) * Intel - vec-report1 * Pathscale - LNO:simd_verbose=ON:vintr_verbose=ON:prefetch_v erbose=ON * GNU - ftree-vectorizer-verbose=1

376

Rare?Earth?Free Permanent Magnets for Electrical Vehicle Motors and Wind Turbine Generators: Hexagonal Symmetry Based Materials Systems Mn?Bi and M?type Hexaferrite  

SciTech Connect (OSTI)

The research we conducted focuses on the rare-earth (RE)-free permanent magnet by modeling, simulating, and synthesizing exchange coupled two-phase (hard/soft) RE-free core-shell nano-structured magnet. The RE-free magnets are made of magnetically hard core materials (high anisotropy materials including Mn-Bi-X and M-type hexaferrite) coated by soft shell materials (high magnetization materials including Fe-Co or Co). Therefore, our research helps understand the exchange coupling conditions of the core/shell magnets, interface exchange behavior between core and shell materials, formation mechanism of core/shell structures, stability conditions of core and shell materials, etc.

Hong, Yang-Ki [University of Alabama] [University of Alabama; Haskew, Timothy [University of Alabama] [University of Alabama; Myryasov, Oleg [University of Alabama] [University of Alabama; Jin, Sungho [University of California San Diego] [University of California San Diego; Berkowitz, Ami [University of California San Diego] [University of California San Diego

2014-06-05T23:59:59.000Z

377

Magnetic insulation  

Science Journals Connector (OSTI)

... by Winterberg1, led me to look into the background of the idea of 'magnetic insulation'. The purpose of this letter is to point out that the scheme described in ... were presented earlier in a longer article2. In that article he suggested that 'magnetic insulation' might make possible a transformer for 109 V. A year later the same objections ...

JOHN P. BLEWETT

1974-06-28T23:59:59.000Z

378

Magnetism1  

Science Journals Connector (OSTI)

... is reached, the rate of diminution becomes very rapid indeed, until, finally, the magnetism of the iron disappears at the same time as for small forces. Instead of ... a lower maximum, and its rise is less rapid. The critical temperature at which magnetism disappears changes rapidly with the composition of the steel. For very soft charcoal iron ...

1890-01-23T23:59:59.000Z

379

Magnetism Group  

Science Journals Connector (OSTI)

... of the Institute of Physics and the Physical Society has announced the establishment of a Magnetism Group. The aim of the new Group is to further interest in ... Group. The aim of the new Group is to further interest in magnetism by holding regular discussion meetings and in other ways. It is intended that these ...

1965-09-04T23:59:59.000Z

380

Terrestrial Magnetism*  

Science Journals Connector (OSTI)

... A similar investigation of the effect of the moon's action on terrestrial magnetism requires a series of observations made at much less distant intervals than the monthly ones ... heat, from the central body of our system, or merely having its own inherent magnetism modified by solar action, then we must choose as our unit the lunation, or ...

1873-01-09T23:59:59.000Z

Note: This page contains sample records for the topic "magnetic vortex core" 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

Terrestrial Magnetism*  

Science Journals Connector (OSTI)

... IN bringing before you this evening, gentlemen, the subject of terrestrial magnetism, it is not my intention to attempt to present you with an exhaustive paper ... clearly as I am able, what is the actual condition of our knowledge respecting the magnetism of the globe, and what the nature of its complex variations, without, however, ...

1873-01-02T23:59:59.000Z

382

Terrestrial Magnetism  

Science Journals Connector (OSTI)

... THE present activity of the department of terrestrial magnetism of the Carnegie Institution of Washington and the largeness of its future aims are alike ... a “progress report” which he contributes to the latest (March) number of Terrestrial Magnetism. The department, which has lately entered on its eleventh year, has under construetion ...

C. CHREE

1914-07-23T23:59:59.000Z

383

Remanent Magnetism  

Science Journals Connector (OSTI)

... STUDY of the natural remanent magnetism of rocks is becoming a familiar method for determining the direction of the Earth's ... the geomagnetic poles or of the continents themselves. An alternative use for measurements of remanent magnetism, namely, the determination of the temperature of formation of pyroclastic deposits, is described ...

1958-03-22T23:59:59.000Z

384

Magnetic shielding  

DOE Patents [OSTI]

A magnetically-conductive filler material bridges the gap between a multi-part magnetic shield structure which substantially encloses a predetermined volume so as to minimize the ingress or egress of magnetic fields with respect to that volume. The filler material includes a heavy concentration of single-magnetic-domain-sized particles of a magnetically conductive material (e.g. soft iron, carbon steel or the like) dispersed throughout a carrier material which is generally a non-magnetic material that is at least sometimes in a plastic or liquid state. The maximum cross-sectional particle dimension is substantially less than the nominal dimension of the gap to be filled. An epoxy base material (i.e. without any hardening additive) low volatility vacuum greases or the like may be used for the carrier material. The structure is preferably exposed to the expected ambient field while the carrier is in a plastic or liquid state so as to facilitate alignment of the single-magnetic-domain-sized particles with the expected magnetic field lines.

Kerns, J.A.; Stone, R.R.; Fabyan, J.

1985-02-12T23:59:59.000Z

385

Watermelon-like iron nanoparticles: Cr doping effect on magnetism and magnetization interaction reversal  

SciTech Connect (OSTI)

Chromium (Cr) forms a solid solution with iron (Fe) lattice when doped in core-shell iron -iron oxide nanocluster (NC) and shows a mixed phase of sigma (?) FeCr and bcc Fe. The Cr dopant affects heavily the magnetization and magnetic reversal process, and causes the hysteresis loop to shrink near the zero field axis. Dramatic transformation happens from dipolar interaction (0 at. % Cr) to strong exchange interaction (8 at. % of Cr) is confirmed from the Henkel plot and delta M plot, and is explained by a water-melon model of core-shell NC system.

Kaur, Maninder; Dai, Qilin; Bowden, Mark E.; Engelhard, Mark H.; Wu, Yaqiao; Tang, Jinke; Qiang, You

2013-06-26T23:59:59.000Z

386

Large core fiber optic cleaver  

DOE Patents [OSTI]

The present invention relates to a device and method for cleaving optical fibers which yields cleaved optical fiber ends possessing high damage threshold surfaces. The device can be used to cleave optical fibers with core diameters greater than 400 {micro}m. 30 figs.

Halpin, J.M.

1996-03-26T23:59:59.000Z

387

Stellar core collapse and supernova  

SciTech Connect (OSTI)

Massive stars that end their stable evolution as their iron cores collapse to a neutron star or black hole long been considered good candidates for producing Type II supernovae. For many years the outward propagation of the shock wave produced by the bounce of these iron cores has been studied as a possible mechanism for the explosion. For the most part, the results of these studies have not been particularly encouraging, except, perhaps, in the case of very low mass iron cores or very soft nuclear equations of state. The shock stalls, overwhelmed by photodisintegration and neutrino losses, and the star does not explode. More recently, slow late time heating of the envelope of the incipient neutron star has been found to be capable of rejuvenating the stalled shock and producing an explosion after all. The present paper discusses this late time heating and presents results from numerical calculations of the evolution, core collapse, and subsequent explosion of a number of recent stellar models. For the first time they all, except perhaps the most massive, explode with reasonable choices of input physics. 39 refs., 17 figs., 1 tab.

Wilson, J.R.; Mayle, R.; Woosley, S.E.; Weaver, T.

1985-04-01T23:59:59.000Z

388

Stability of Molten Core Materials  

SciTech Connect (OSTI)

The purpose of this report is to document a literature and data search for data and information pertaining to the stability of nuclear reactor molten core materials. This includes data and analysis from TMI-2 fuel and INL’s LOFT (Loss of Fluid Test) reactor project and other sources.

Layne Pincock; Wendell Hintze

2013-01-01T23:59:59.000Z

389

Wright State University CORE Scholar  

E-Print Network [OSTI]

Wright State University CORE Scholar Psychology Faculty Publications Psychology 10-1-2010 The Statistical Properties of the Survivor Interaction Contrast Joseph W. Houpt Wright State University - Main Campus, joseph.houpt@wright.edu James T. Townsend Follow this and additional works at: http://corescholar.libraries.wright

Townsend, James T.

390

Superconducting Magnets  

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

Mit Hilfe der Technologie supraleitender Magnete lassen sich in Mit Hilfe der Technologie supraleitender Magnete lassen sich in Ringbeschleunigern höhere Energien erreichen. Weil supraleitende Spulen keinen elektrischen Widerstand aufweisen, können damit stärkere Magnetfelder erzeugt werden. In normal leitenden Elektromagneten wird - wegen des elektrischen Widerstands der Drähte - die Spule aufgeheizt. Auf diese Weise geht sehr viel Energie in Form von Wärme verloren, was die Energiekosten dieser Magnete in die Höhe treibt. Supraleitende Spulen erlauben es, Magnete grosser Feldstärke unter günstigen Bedingungen zu betreiben und damit die Energiekosten zu senken. Durch den Einbau supraleitender Spulen in den Ringbeschleuniger von Fermilab konnte dessen Energie verdoppelt werden.Auch der im Bau befindliche "Large Hadron Collider" am CERN wird supraleitende Magnete

391

Magnetic nanotubes  

DOE Patents [OSTI]

A magnetic nanotube includes bacterial magnetic nanocrystals contacted onto a nanotube which absorbs the nanocrystals. The nanocrystals are contacted on at least one surface of the nanotube. A method of fabricating a magnetic nanotube includes synthesizing the bacterial magnetic nanocrystals, which have an outer layer of proteins. A nanotube provided is capable of absorbing the nanocrystals and contacting the nanotube with the nanocrystals. The nanotube is preferably a peptide bolaamphiphile. A nanotube solution and a nanocrystal solution including a buffer and a concentration of nanocrystals are mixed. The concentration of nanocrystals is optimized, resulting in a nanocrystal to nanotube ratio for which bacterial magnetic nanocrystals are immobilized on at least one surface of the nanotubes. The ratio controls whether the nanocrystals bind only to the interior or to the exterior surfaces of the nanotubes. Uses include cell manipulation and separation, biological assay, enzyme recovery, and biosensors.

Matsui, Hiroshi (Glen Rock, NJ); Matsunaga, Tadashi (Tokyo, JP)

2010-11-16T23:59:59.000Z

392

Unusual Structure and Magnetism in MnO Nanoclusters  

E-Print Network [OSTI]

We report an unusual evolution of structure and magnetism in stoichiometric MnO clusters based on an extensive and unbiased search through the potential energy surface within density functional theory. The smaller clusters, containing up to five MnO units, adopt two-dimensional structures; and regardless of the size of the cluster, magnetic coupling is found to be antiferromagnetic in contrast to previous theoretical findings. Predicted structure and magnetism are strikingly different from the magnetic core of Mn-based molecular magnets, whereas they were previously argued to be similar. Both of these features are explained through the inherent electronic structures of the clusters.

Ganguly, Shreemoyee; Sanyal, Biplab; Mookerjee, Abhijit; 10.1103/PhysRevB.83.020411

2011-01-01T23:59:59.000Z

393

Tropical Cyclone Initialization with a Spherical High-Order Filter and an Idealized Three-Dimensional Bogus Vortex  

Science Journals Connector (OSTI)

A tropical cyclone initialization method with an idealized three-dimensional bogus vortex of an analytic empirical formula is presented for the track and intensity prediction. The procedure in the new method consists of four steps: the separation ...

In-Hyuk Kwon; Hyeong-Bin Cheong

2010-04-01T23:59:59.000Z

394

Study of permanent-magnet couplings with progressive magnetization using an analytical formulation  

SciTech Connect (OSTI)

Permanent-magnet (PM) magnetic couplings are used in many industrial applications. They allow the transmission of a torque from a rotating part to another rotating part without any mechanical contact. They are used in sealed equipment to transmit a movement through a separation wall. They are also very useful in high security applications to avoid failures due to torque overload. Nonclassical structures of permanent-magnet cylindrical air-gap couplings with progressive magnetization are studied. In these couplings, parallelepiped magnets with nonclassical magnetization direction are used and stuck in ironless cores. The magnetization direction of each magnet is chosen to provide an optimal repartition of the induction in the air gap. This progressive magnetization allows very high values of pullout torque. The use of this type of structure with ironless cores and very high pull-out torque seems to be an advantageous way to minimize the inertia and maximize the pullout torque of a magnetic coupling. An efficient method to calculate the torque of such a coupling is presented, based on analytical formulas for forces between magnets. It allows the exact evaluation of the performance of the studied couplings when the main dimensions of the coupling are varying with small calculation time. In this paper the influence of the number of pole pairs, the influence of the number of magnets per pole, the influence of the magnets' thickness, the influence of the air-gap radius, and the influence of the length of the structure are studied and discussed. Then some general rules are presented for efficient design of such a coupling.

Charpentier, J.F.; Lemarquand, G.

1999-09-01T23:59:59.000Z

395

Logging-while-coring method and apparatus  

DOE Patents [OSTI]

A method and apparatus for downhole coring while receiving logging-while-drilling tool data. The apparatus includes core collar and a retrievable core barrel. The retrievable core barrel receives core from a borehole which is sent to the surface for analysis via wireline and latching tool The core collar includes logging-while-drilling tools for the simultaneous measurement of formation properties during the core excavation process. Examples of logging-while-drilling tools include nuclear sensors, resistivity sensors, gamma ray sensors, and bit resistivity sensors. The disclosed method allows for precise core-log depth calibration and core orientation within a single borehole, and without at pipe trip, providing both time saving and unique scientific advantages.

Goldberg, David S. (New York, NY); Myers, Gregory J. (Cornwall, NY)

2007-11-13T23:59:59.000Z

396

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

397

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

398

3184 IEEE TRANSACTIONS ON MAGNETICS, VOL. 39, NO. 5, SEPTEMBER 2003 Ultralow-Profile Micromachined Power Inductors  

E-Print Network [OSTI]

efficiency power conversion solutions in these applications. The key challenge in implementing miniaturized-scale lamination of Ni/Fe cores, combined with three-dimensional micromachined copper windings. The magnetic core, allowing for the storage of larger amounts of magnetic energy per unit volume. The typical disadvantage

399

Linear chain magnetism  

Science Journals Connector (OSTI)

Linear chain magnetism ... A brief introduction to this concept, which is also called lower dimensional magnetism. ...

Richard L. Carlin

1991-01-01T23:59:59.000Z

400

ur solid Earth undergoes constant change from motions within its core  

E-Print Network [OSTI]

O ur solid Earth undergoes constant change from motions within its core to the surface. Solid Earth is the physical planet we live on, not the oceans or atmosphere. Motions near Earth's cen- ter affect the geodynamo, which generates the Earth's magnetic field. Convection within Earth's mantle drives plate

McLeod, Dennis

Note: This page contains sample records for the topic "magnetic vortex core" 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

Trapping of ultracold atoms in a hollow-core photonic crystal fiber Caleb A. Christensen,1  

E-Print Network [OSTI]

light in multiple modes in the cladding or core. Such fibers are susceptible to speckle or inhomogeneous have succeeded in trapping ultracold atoms 13 or guiding thermal 14 or laser-cooled atoms 15 through laser cooling and rf evaporation in a dc Ioffe-Pritchard magnetic trap, then load the BEC into a red

402

Magnetic collimation of fast electrons in specially engineered targets irradiated by ultraintense laser pulses  

SciTech Connect (OSTI)

The efficient magnetic collimation of fast electron flow transporting in overdense plasmas is investigated with two-dimensional collisional particle-in-cell numerical simulations. It is found that the specially engineered targets exhibiting either high-resistivity-core-low-resistivity-cladding structure or low-density-core-high-density-cladding structure can collimate fast electrons. Two main mechanisms to generate collimating magnetic fields are found. In high-resistivity-core-low-resistivity-cladding structure targets, the magnetic field at the interfaces is generated by the gradients of the resistivity and fast electron current, while in low-density-core-high-density-cladding structure targets, the magnetic field is generated by the rapid changing of the flow velocity of the background electrons in transverse direction (perpendicular to the flow velocity) caused by the density jump. The dependences of the maximal magnetic field on the incident laser intensity and plasma density, which are studied by numerical simulations, are supported by our analytical calculations.

Cai Hongbo [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China); Center for Applied Physics and Technology, Peking University, Beijing 100871 (China); Zhu Shaoping; Wu Sizhong; Chen Mo; Zhou Cangtao [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China); He, X. T. [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China); Center for Applied Physics and Technology, Peking University, Beijing 100871 (China); Institute for Fusion Theory and Simulation, Zhejiang University, Hangzhou 310027 (China); Yu Wei [Shanghai Institute of Optics and Fine Mechanics, Shanghai 201800 (China); Nagatomo, Hideo [Institute of Laser Engineering, Osaka University, 2-6 Yamadaoka, Suita, Osaka 565-0871 (Japan)

2011-02-15T23:59:59.000Z

403

Low dimensional magnetism  

E-Print Network [OSTI]

Magnetism in Ultracold Gases 4 Magnetic phase diagram of aMagnetism . . . . . . . . . . . .1.3 Magnetism in condensedIntroduction 1 Brief introduction to magnetism 1.1 Classic

Kjall, Jonas Alexander

2012-01-01T23:59:59.000Z

404

Methods of classical mechanics applied to turbulence stresses in a tip leakage vortex  

SciTech Connect (OSTI)

Moore et al. measured the six Reynolds stresses in a tip leakage vortex in a linear turbine cascade. Stress tensor analysis, as used in classical mechanics, has been applied to the measured turbulence stress tensors. Principal directions and principal normal stresses are found. A solid surface model, or three-dimensional glyph, for the Reynolds stress tensor is proposed and used to view the stresses throughout the tip leakage vortex. Modeled Reynolds stresses using the Boussinesq approximation are obtained from the measured mean velocity strain rate tensor. The comparison of the principal directions and the three-dimensional graphic representations of the strain and Reynolds stress tensors aids in the understanding of the turbulence and what is required to model it.

Moore, J.G.; Schorn, S.A.; Moore, J. [Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States)

1996-10-01T23:59:59.000Z

405

A model for vortex-induced vibration analysis of long-span bridges  

Science Journals Connector (OSTI)

Abstract Long-span structures are susceptible to wind-induced vibrations due to their low oscillation frequency and low mechanical damping. Although many efforts have been made in the past to model vortex-induced vibration of circular cylinders, limited studies can be found for non-circular cross sections representative of long-span bridge decks. A model for vortex-induced vibration analysis of long-span bridge is presented in this paper. The aeroelastic equation of motion of the model, a procedure to extract aeroelastic coefficients from wind tunnel experiments, analysis of full-scale structures incorporating loss of spanwise correlation of aeroelastic forces, and comparison between simulated and full-scale measured responses on a twin deck bridge (Fred Hartman bridge, Baytown, Texas) are discussed. Six bluff sections – Deer Isle bridge, Tsurumi bridge, Fred Hartman bridge, generic rectangular, H shaped, and circular models – were considered in this research program.

Mehedy Mashnad; Nicholas P. Jones

2014-01-01T23:59:59.000Z

406

Processing of Activated Core Components  

SciTech Connect (OSTI)

Used activated components from the core of a NPP like control elements, water channels from a BWR, and others like in-core measurement devices need to be processed into waste forms suitable for interim storage, and for the final waste repository. Processing of the activated materials can be undertaken by underwater cutting and packaging or by cutting and high-pressure compaction in a hot cell. A hot cell is available in Germany as a joint investment between GNS and the Karlsruhe Research Center at the latter's site. Special transport equipment is available to transport the components ''as-is'' to the hot cell. Newly designed underwater processing equipment has been designed, constructed, and operated for the special application of NPP decommissioning. This equipment integrates an underwater cutting device with an 80 ton force underwater in-drum compactor.

Friske, A.; Gestermann, G.; Finkbeiner, R.

2003-02-26T23:59:59.000Z

407

Magnetic Viscosity  

Science Journals Connector (OSTI)

1 January 1893 research-article Magnetic Viscosity J. Hopkinson E. Wilson F. Lydall The Royal Society is collaborating with JSTOR to digitize, preserve, and extend access to Proceedings of the Royal Society of London. www.jstor.org

1893-01-01T23:59:59.000Z

408

Rock magnetism  

Science Journals Connector (OSTI)

The past three decades have witnessed a new paradigm, the plate tectonics paradigm, in Earth sciences. The record of the Earth's magnetic field stored in rocks played a major role in the establishment of this par...

Ronald T. Merrill

1989-01-01T23:59:59.000Z

409

TMI-2 core shipping preparations  

SciTech Connect (OSTI)

Shipping the damaged core from the Unit 2 reactor of Three Mile Island Nuclear Power Station near Harrisburg, PA, to the Idaho National Engineering Laboratory near Idaho Falls, ID, required development and implementation of a completely new spent fuel transportation system. This paper describes the equipment developed, the planning and activities used to implement the hardware systems into the facilities, and the planning involved in making the rail shipments. It also includes a summary of recommendations resulting from this experience.

Ball, L.J.; (EG and G Idaho, Inc., Idaho Falls, ID (United States)); Barkanic, R.J. (Bechtel North American Power Corporation (United States)); Conaway, W.T. II (GPU Nuclear Corporation, Three Mile Island, Middletown, PA (United States)); Schmoker, D.S. (Nuclear Packaging, Inc., Federal Way, WA (United States))

1988-01-01T23:59:59.000Z

410

Laminated electromagnetic pump stator core  

DOE Patents [OSTI]

A stator core for an electromagnetic pump includes a plurality of circumferentially abutting tapered laminations extending radially outwardly from a centerline axis to collectively define a radially inner bore and a radially outer circumference. Each of the laminations includes radially inner and outer edges and has a thickness increasing from the inner edge toward the outer edge to provide a substantially continuous path adjacent the circumference. This pump is used in nuclear fission reactors. 19 figs.

Fanning, A.W.

1995-08-08T23:59:59.000Z

411

Getting to the Core of Luminescent Nanowires | Advanced Photon Source  

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

Giant Magnetocaloric Materials Could Have Large Impact on the Environment Giant Magnetocaloric Materials Could Have Large Impact on the Environment Tracking the Origins of Fossil Fuels Tailoring the Properties of Magnetic Nanostructures X-ray Holograms Expose Secret Magnetism How Dissolved Metal Ions Interact in Solution Science Highlights Archives: 2013 | 2012 | 2011 | 2010 2009 | 2008 | 2007 | 2006 2005 | 2004 | 2003 | 2002 2001 | 2000 | 1998 | Subscribe to APS Science Highlights rss feed Getting to the Core of Luminescent Nanowires JUNE 18, 2007 Bookmark and Share Schematic representations of the two types of nanowire structures are shown on the right and typical luminescence spectra are shown on the left. By monitoring the energy dependence of the different emission channels, particularly at the Zn L3 edge (shown), the local origin of those levels is

412

Learning About Magnets!  

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

the the National High Magnetic Field Laboratory Learning About Name A magnet is a material or object that creates a magnetic fi eld. This fi eld is invisible, but it creates a force that can "attract" or "repel" other magnets and magnetic materials, like iron or nickel. What is a Magnet? This bar magnet is a permanent magnet. Permanent magnets can be found in the Earth as rocks and metals. Magnets have

413

Quasi-geostrophic modes in the Earth's fluid core with an outer stably stratified layer  

E-Print Network [OSTI]

Seismic waves sensitive to the outermost part of the Earth's liquid core seem to be affected by a stably stratified layer at the core-mantle boundary. Such a layer could have an observable signature in both long-term and short-term variations of the magnetic field of the Earth, which are used to probe the flow at the top of the core. Indeed, with the recent SWARM mission, it seems reasonable to be able to identify waves propagating in the core with period of several months, which may play an important role in the large-scale dynamics. In this paper, we characterize the influence of a stratified layer at the top of the core on deep quasi-geostrophic (Rossby) waves. We compute numerically the quasi-geostrophic eigenmodes of a rapidly rotating spherical shell, with a stably stratified layer near the outer boundary. Two simple models of stratification are taken into account, which are scaled with commonly accepted values of the Brunt-V{\\"a}is{\\"a}l{\\"a} frequency in the Earth's core. In the absence of magnetic fi...

Vidal, Jérémie

2015-01-01T23:59:59.000Z

414

Reduced gravity Rankine cycle system design and optimization study with passive vortex phase separation  

E-Print Network [OSTI]

REDUCED GRAVITY RANKINE CYCLE SYSTEM DESIGN AND OPTIMIZATION STUDY WITH PASSIVE VORTEX PHASE SEPARATION A Thesis by KEVIN ROBERT SUPAK Submitted to the Office of Graduate Studies of Texas A&M University... SEPARATION A Thesis by KEVIN ROBERT SUPAK Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Approved by: Chair of Committee, Frederick...

Supak, Kevin Robert

2008-10-10T23:59:59.000Z

415

Effects of syngas composition on combustion induced vortex breakdown (CIVB) flashback in a swirl stabilized combustor  

Science Journals Connector (OSTI)

Flame flashback attributed to combustion induced vortex breakdown (CIVB) is a major design challenge for swirl stabilized burner combustors. This paper presents an experimental investigation of combustion induced vortex breakdown (CIVB) flashback propensity for flames yielded from Hydrogen (H2)–Carbon Monoxide (CO) fuel blends and actual synthesized gas (syngas) mixtures. A two-fold experimental approach, consisting of a high definition digital imaging system and a high speed PIV system, was employed. The main emphasis was on the effect of concentration of different constituents in fuel mixtures on flashback limit. In addition, the effect of Swirl Number on flashback propensity was discussed. The percentage of H2 in fuel mixtures played the dominant role when CIVB flashback occurred. For a given air mass flow rate, the mixture containing a higher percentage of H2 underwent flashback at much leaner conditions. Flashback maps for actual syngas fuel compositions showed a distinct behavior when various concentrations of diluents were introduced in the mixture. For the two major diluents tested, carbon dioxide (CO2) and nitrogen dioxide (NO2), CO2 was more dominant. The effect of Swirl Number on the flashback propensity was also tested and showed a decrease with an increase in Swirl Number. The final portion of this paper also provides an analysis of flow field of reacting flames which revealed complex vortex–chemistry interactions leading to vortex breakdown and flashback. Based on the experimental results a parametric model similar to Peclet Number approach was developed employing a flame quenching concept. A value of the quench parameter, Cquench was obtained from the correlation of flow Peclet Number and flame Peclet Number, which was observed to be dominated by the fuel composition rather than Swirl Number.

Bidhan Dam; Gilberto Corona; Mir Hayder; Ahsan Choudhuri

2011-01-01T23:59:59.000Z

416

Aircraft Emissions Deposited in the Stratosphere and Within the Arctic Polar Vortex. Final report  

SciTech Connect (OSTI)

This report describes an analysis of the quantity of emissions (water vapor, NO(x)) projected to be deposited directly within the Arctic polar vortex by projected fleets of Mach 2.4 high speed civil transports (HSCT`s). It also evaluates the amount of emissions from subsonic aircraft which are emitted into the lower stratosphere using aircraft emission inventories developed earlier for May 1990 as representative of the annual average.

Baughcum, S.L.

1996-04-01T23:59:59.000Z

417

Three-Dimensional Nonlinear Lattices: From Oblique Vortices and Octupoles to Discrete Diamonds and Vortex Cubes  

Science Journals Connector (OSTI)

We construct a variety of novel localized topological structures in the 3D discrete nonlinear Schrödinger equation. The states can be created in Bose-Einstein condensates trapped in strong optical lattices and crystals built of microresonators. These new structures, most of which have no counterparts in lower dimensions, range from multipole patterns and diagonal vortices to vortex “cubes” (stack of two quasiplanar vortices) and “diamonds” (formed by two orthogonal vortices).

R. Carretero-González; P. G. Kevrekidis; B. A. Malomed; D. J. Frantzeskakis

2005-05-23T23:59:59.000Z

418

HyCore | Open Energy Information  

Open Energy Info (EERE)

HyCore Jump to: navigation, search Name: HyCore Place: Norway Sector: Hydro, Solar Product: JV between Umicore and Norsk Hydro to manufacture solar-grade silicon. References:...

419

Matrix Acidizing Parallel Core Flooding Apparatus  

E-Print Network [OSTI]

and provide this information to the field. To conduct various experiments, core flooding setups are created. The setup consists of a core holder, accumulator, overburden pump, injection pump, accumulator, pressure sensors, and a back pressure regulator...

Ghosh, Vivek

2013-07-23T23:59:59.000Z

420

Controlling Magnetism at the Nanoscale  

E-Print Network [OSTI]

Manipulation of Magnetism - External148 Conclusion A The Magnetism Cheat Sheet A.1 Magnetic157 A.2 Magnetism Unit Conversion

Wong, Jared

2012-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "magnetic vortex core" 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

The SimCore/Alpha Functional Simulator  

Science Journals Connector (OSTI)

We have developed a function-level processor simulator, SimCore/Alpha Functional Simulator Version 2.0 (SimCore Version 2.0), for processor architecture research and processor education. This paper describes the design and implementation of SimCore Version ...

Kenji Kise; Takahiro Katagiri; Hiroki Honda; Toshitsugu Yuba

2004-06-01T23:59:59.000Z

422

Core Competency Worksheets for Significant Cybersecurity Roles  

Broader source: Energy.gov [DOE]

OCIO has developed core competency worksheets for significant cyber roles to assist training personnel, curricula developers, supervisors, etc. with identifying core skills needed to perform their functional roles. Core competencies can be used to develop training objectives for site or organization-specific role-based training.

423

GCFR core thermal-hydralic design  

SciTech Connect (OSTI)

The approach for developing the thermal-hydraulic core assembly designs for the gas-cooled fast reactor (GCFR) is reviewed, and key considerations for improving the core performance at all power and flow conditions are discussed. It is shown how the thermal-hydraulic core assembly designs evolve from evaluations of plant size, material limitations, safety criteria, and structural performance considerations.

Schleuter, G.; Baxi, C.B.; Bennett, F.O.

1980-05-01T23:59:59.000Z

424

Russian techniques for more productive core drilling  

SciTech Connect (OSTI)

This is a short discussion of the trends and technology being used in Russia to increase the production of core drilling. The currently used rigs are given with the plans for improvement in drive methods and to reduce trip time in the recovery of cores. The recommendations by the Russians to improve the core recovery quality and quantity are also given.

Not Available

1984-09-01T23:59:59.000Z

425

Energy cost associated with vortex crossing in superconductors  

Science Journals Connector (OSTI)

Starting from the Ginzburg-Landau free energy of a type-II superconductor in a magnetic field we estimate the energy associated with two vortices crossing. The calculations are performed by assuming that we are in a part of the phase diagram where the lowest-Landau-level approximation is valid. We consider only two vortices but with two markedly different sets of boundary conditions: on a sphere and on a plane with quasiperiodic boundary conditions. We find that the answers are very similar suggesting that the energy is localized to the crossing point. The crossing energy is found to be field and temperature dependent with a value at the experimentally measured melting line of U×?7.5kTm?1.16/cL2, where cL is the Lindemann-melting-criterion parameter. The crossing energy is then used with an extension of the Marchetti, Nelson, and Cates hydrodynamic theory to suggest an explanation of the recent transport experiments of Safar et al.

M. A. Moore and N. K. Wilkin

1994-10-01T23:59:59.000Z

426

Phonon spectrum of QCD vacuum in magnetic-field-induced superconducting phase  

E-Print Network [OSTI]

In the background of a sufficiently strong magnetic field the vacuum was suggested to become an ideal electric conductor (highly anisotropic superconductor) due to an interplay between the strong and electromagnetic forces. The superconducting ground state resembles an Abrikosov lattice state in an ordinary type-II superconductor: it is an inhomogeneous structure made of a (charged vector) quark-antiquark condensate pierced by vortices. In this paper the acoustic (phonon) vibrational modes of the vortex lattice are studied in the mean-field approach at zero temperature. Using an effective model based on a vector meson dominance, we show that in the infrared limit the longitudinal (transverse) acoustic vibrations of the vortex lattice possess a linear (quadratic) dispersion relation corresponding to type I (type II) Nambu-Goldstone modes.

Chernodub, M N; Verschelde, Henri

2014-01-01T23:59:59.000Z

427

Phonon spectrum of QCD vacuum in magnetic-field-induced superconducting phase  

E-Print Network [OSTI]

In the background of a sufficiently strong magnetic field the vacuum was suggested to become an ideal electric conductor (highly anisotropic superconductor) due to an interplay between the strong and electromagnetic forces. The superconducting ground state resembles an Abrikosov lattice state in an ordinary type--II superconductor: it is an inhomogeneous structure made of a (charged vector) quark-antiquark condensate pierced by vortices. In this paper the acoustic (phonon) vibrational modes of the vortex lattice are studied at zero temperature. Using an effective model based on a vector meson dominance, we show that in the infrared limit the longitudinal (transverse) acoustic vibrations of the vortex lattice possess a linear (quadratic) dispersion relation corresponding to type I (type II) Nambu--Goldstone modes.

M. N. Chernodub; Jos Van Doorsselaere; Henri Verschelde

2014-01-01T23:59:59.000Z

428

Neutrino magnetic moment in a magnetized plasma  

E-Print Network [OSTI]

The contribution of a magnetized plasma to the neutrino magnetic moment is calculated. It is shown that only part of the additional neutrino energy in magnetized plasma connecting with its spin and magnetic field strength defines the neutrino magnetic moment. It is found that the presence of magnetized plasma does not lead to the considerable increase of the neutrino magnetic moment in contrast to the results presented in literature previously.

N. V. Mikheev; E. N. Narynskaya

2010-11-08T23:59:59.000Z

429

Magnetic field amplification and magnetically supported explosions of collapsing, non-rotating stellar cores  

Science Journals Connector (OSTI)

......2004), multidimensional, energy-dependent flux-limited diffusion...employ a new multidimensional and energy-dependent scheme for the neutrino...two-moment solver for the neutrino energy (lepton number) and momentum...Pons, Ibanez Miralles 2000; Audit et-al. 2002). Two-moment......

M. Obergaulinger; H.-Th. Janka; M. A. Aloy

2014-01-01T23:59:59.000Z

430

DOE CYBER SECURITY EBK: MINIMUM CORE COMPETENCY TRAINING REQUIREMENTS...  

Office of Environmental Management (EM)

DOE CYBER SECURITY EBK: MINIMUM CORE COMPETENCY TRAINING REQUIREMENTS DOE CYBER SECURITY EBK: MINIMUM CORE COMPETENCY TRAINING REQUIREMENTS DOE CYBER SECURITY EBK: CORE COMPETENCY...

431

DOE CYBER SECURITY EBK: CORE COMPETENCY TRAINING REQUIREMENTS...  

Broader source: Energy.gov (indexed) [DOE]

CORE COMPETENCY TRAINING REQUIREMENTS: CA DOE CYBER SECURITY EBK: CORE COMPETENCY TRAINING REQUIREMENTS: CA DOE CYBER SECURITY EBK: CORE COMPETENCY TRAINING REQUIREMENTS. Key Cyber...

432

Effect of Side Permanent Magnets for Reluctance Interior Permanent Magnet Reluctance Machines  

SciTech Connect (OSTI)

A traditional electric machine uses two dimensional magnetic flux paths in its rotor. This paper presents the development work on the utilization of the third dimension of a rotor. As an example, the air gap flux of a radial gap interior permanent magnet motor can be significantly enhanced by additional permanent magnets (PM) mounted at the sides of the rotor. A prototype motor built with this concept provided higher efficiency and required a shorter stator core length for the same power output as the Toyota/Prius traction drive motor.

Hsu, John S [ORNL; Lee, Seong T [ORNL; Wiles, Randy H [ORNL; Coomer, Chester [ORNL; Lowe, Kirk T [ORNL

2007-01-01T23:59:59.000Z

433

Core Coupling in Nb-99  

E-Print Network [OSTI]

to be good. NUCLEAR REACTIONS, NUCLEAR STRUCTURE '"Mop, 'He), E =40.7 Mev, measured o(8) 99Nb levels deduced S. Calculated levels, 4, n', 8 NNb, particle- core-coupling model. The proton configurations of nuclei in the Zr-Mo region have been the subject... of much experimental interest. ' ' The only information available on ~Nb, however, was obtained by measurement of y decay following 99Zr P decay, ~ and is rather lim- ited. We have studied the levels of "Nb with the Mo(d, 'He) reaction at 40.7-Me...

Bindal, P. K.; Youngblood, David H.

1974-01-01T23:59:59.000Z

434

SoCore Energy | Open Energy Information  

Open Energy Info (EERE)

SoCore Energy SoCore Energy Jump to: navigation, search Name SoCore Energy Place Chicago, Illinois Zip 60601 Sector Solar Product Chicago-based solar installer and mounting solution company that also arranges for solar loans and PPAs. References SoCore Energy[1] LinkedIn Connections CrunchBase Profile No CrunchBase profile. Create one now! This article is a stub. You can help OpenEI by expanding it. SoCore Energy is a company located in Chicago, Illinois . References ↑ "SoCore Energy" Retrieved from "http://en.openei.org/w/index.php?title=SoCore_Energy&oldid=351218" Categories: Clean Energy Organizations Companies Organizations Stubs What links here Related changes Special pages Printable version Permanent link Browse properties About us Disclaimers Energy blogs

435

Petroglyphs, Lighting, and Magnetism  

E-Print Network [OSTI]

1950 Electricity and Magnetism: Theory and Applications.I Petroglyphs, Lightning, and Magnetism | Walker Figure 8.I Petroglyphs, Lightning, and Magnetism | Walker Figure IL

Walker, Merle F

2007-01-01T23:59:59.000Z

436

Magnetic properties of Pleistocene-Pliocene sediments from hole 810C, Shatsky Rise, and implications for the origin and correlatibility of their magnetic susceptibility variations  

E-Print Network [OSTI]

the summit of the rise, using the advanced hydraulic piston corer to achieve virtually complete recovery in the upper 127 meters below the sea floor. The down-core stratigraphy of whole-core magnetic susceptibility displayed peaks with amplitudes of 30-40 x...

Polgreen, Evelyn Louise

2012-06-07T23:59:59.000Z

437

Effects of Magnetic Field on the Turbulent Wake of a Cylinder in MHD Channel Flow  

SciTech Connect (OSTI)

Results from a free-surface MHD flow experiment are presented detailing the modi cation of vortices in the wake of a circular cylinder with its axis parallel to the applied magnetic fi eld. Experiments were performed with a Reynolds number near Re ~ 104 as the interaction parameter, N = |j x#2; B| / |? (? ? ?), was increased through unity. By concurrently sampling the downstream fluid velocity at sixteen cross-stream locations in the wake, it was possible to extract an ensemble of azimuthal velocity profi les as a function of radius for vortices shed by the cylinder at varying strengths of magnetic field. Results indicate a signi cant change in vortex radius and rotation as N is increased. The lack of deviations from the vortex velocity pro file at high magnetic fi elds suggests the absence of small-scale turbulent features. By sampling the wake at three locations downstream in subsequent experiments, the decay of the vortices was examined and the effective viscosity was found to decrease as N-049±0.4. This reduction in effective viscosity is due to the modi cation of the small-scale eddies by the magnetic fi eld. The slope of the energy spectrum was observed to change from a k-1.8 power-law at low N to a k-3.5 power-law for N > 1. Together, these results suggest the flow smoothly transitioned to a quasi-two-dimensional state in the range 0 < N < 1.

John Rhoads, Eric Edlund and Hantao Ji

2013-04-17T23:59:59.000Z

438

Magnetic Monopoles and Cosmic Inflation  

E-Print Network [OSTI]

It is possible that the expansion of the universe began with an inflationary phase, in which the inflaton driving the process also was a Higgs field capable of stabilizing magnetic monopoles in a grand-unified gauge theory. If so, then the smallness of intensity fluctuations observed in the cosmic microwave background radiation implies that the self-coupling of the inflaton-Higgs field was exceedingly weak. It is argued here that the resulting broad, flat maximum in the Higgs potential makes the presence or absence of a topological zero in the field insignificant for inflation. There may be monopoles present in the universe, but the universe itself is not in the inflating core of a giant magnetic monopole.

Alfred Scharff Goldhaber

2005-12-09T23:59:59.000Z

439

Magnetic Catalysis vs Magnetic Inhibition  

E-Print Network [OSTI]

We discuss the fate of chiral symmetry in an extremely strong magnetic field B. We investigate not only quark fluctuations but also neutral meson effects. The former would enhance the chiral-symmetry breaking at finite B according to the Magnetic Catalysis, while the latter would suppress the chiral condensate once B exceeds the scale of the hadron structure. Using a chiral model we demonstrate how neutral mesons are subject to the dimensional reduction and the low dimensionality favors the chiral-symmetric phase. We point out that this effect, the Magnetic Inhibition, can be a feasible explanation for recent lattice-QCD data indicating the decreasing behavior of the chiral-restoration temperature with increasing B.

Kenji Fukushima; Yoshimasa Hidaka

2012-09-06T23:59:59.000Z

440

Magnetic Stereoscopy  

E-Print Network [OSTI]

The space mission STEREO will provide images from two viewpoints. An important aim of the STEREO mission is to get a 3D view of the solar corona. We develop a program for the stereoscopic reconstruction of 3D coronal loops from images taken with the two STEREO spacecraft. A pure geometric triangulation of coronal features leads to ambiguities because the dilute plasma emissions complicates the association of features in image 1 with features in image 2. As a consequence of these problems the stereoscopic reconstruction is not unique and multiple solutions occur. We demonstrate how these ambiguities can be resolved with the help of different coronal magnetic field models (potential, linear and non-linear force-free fields). The idea is that, due to the high conductivity in the coronal plasma, the emitting plasma outlines the magnetic field lines. Consequently the 3D coronal magnetic field provides a proxy for the stereoscopy which allows to eliminate inconsistent configurations. The combination of stereoscopy and magnetic modelling is more powerful than one of these tools alone. We test our method with the help of a model active region and plan to apply it to the solar case as soon as STEREO data become available.

Thomas Wiegelmann; Bernd Inhester

2006-12-21T23:59:59.000Z

Note: This page contains sample records for the topic "magnetic vortex core" 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

Earth Planets Space, 52, 329336, 2000 Rock magnetism of sediments in the Angola-Namibia upwelling system  

E-Print Network [OSTI]

Earth Planets Space, 52, 329�336, 2000 Rock magnetism of sediments in the Angola-Namibia upwelling system with special reference to loss of magnetization after core recovery Toshitsugu Yamazaki1 , Peter A Magnetism, University of Minnesota, Minneapolis, MN 55455-0128, U.S.A. 3Hawaii Institute of Geophysics

Yamazaki, Toshitsugu

442

Turbine blade platform film cooling with simulated stator-rotor purge flow with varied seal width and upstream wake with vortex  

E-Print Network [OSTI]

phase locations to model the unsteady wake formed at the trailing edge of the upstream vane. Delta wings were also placed in four positions to create a vortex similar to the passage vortex at the exit of the vane. The film cooling effectiveness...

Blake, Sarah Anne

2009-05-15T23:59:59.000Z

443

Core Capabilities | Argonne National Laboratory  

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

The Advanced Photon Source is one of the brightest sources of X-rays in the The Advanced Photon Source is one of the brightest sources of X-rays in the Western Hemisphere. Photons are accelerated to over 99% of the speed of light around its ring, which is the size of a baseball stadium. To view a larger version of the image, click on it. The Center for Nanoscale Materials at Argonne is a premier user facility, providing expertise, instruments, and infrastructure for interdisciplinary nanoscience and nanotechnology research. To view a larger version of the image, click on it. Core Capabilities Argonne's vision is to lead the world in discovery science and engineering that provides technical solutions to the grand challenges of our time. Argonne's vision is to lead the world in discovery science and engineering that provides technical solutions to the grand challenges of our time:

444

Test report -- Prototype core sampler  

SciTech Connect (OSTI)

The purpose of this test is to determine the adequacy of the prototype sampler, provided to Westinghouse Hanford Company (WHC) by DOE-RL. The sampler was fabricated for DOE-RL by the Concord Company by request of DOE-RL. This prototype sampler was introduced as a technology that can be easily deployed (similar to the current auger system) and will reliably collect representative samples. The sampler is similar to the Universal Sampler i.e., smooth core barrel and piston with an O-ring seal, but lacks a rotary valve near the throat of the sampler. This makes the sampler inappropriate for liquid sampling, but reduces the outside diameter of the sampler considerably, which should improve sample recovery. Recovery testing was performed with the supplied sampler in three different consistencies of Kaolin sludge simulants.

Linschooten, C.G.

1995-01-17T23:59:59.000Z

445

Nuclear core and fuel assemblies  

DOE Patents [OSTI]

A fast flux nuclear core of a plurality of rodded, open-lattice assemblies having a rod pattern rotated relative to a rod support structure pattern. Elongated fuel rods are oriented on a triangular array and laterally supported by grid structures positioned along the length of the assembly. Initial inter-assembly contact is through strongbacks at the corners of the support pattern and peripheral fuel rods between adjacent assemblies are nested so as to maintain a triangular pitch across a clearance gap between the other portions of adjacent assemblies. The rod pattern is rotated relative to the strongback support pattern by an angle .alpha. equal to sin .sup.-1 (p/2c), where p is the intra-assembly rod pitch and c is the center-to-center spacing among adjacent assemblies.

Downs, Robert E. (Monroeville, PA)

1981-01-01T23:59:59.000Z

446

WAVE-VORTEX MODE COUPLING IN ASTROPHYSICAL ACCRETION DISKS UNDER COMBINED RADIAL AND VERTICAL STRATIFICATION  

SciTech Connect (OSTI)

We examine accretion disk flow under combined radial and vertical stratification utilizing a local Cartesian (or ''shearing box'') approximation. We investigate both axisymmetric and nonaxisymmetric disturbances with the Boussinesq approximation. Under axisymmetric disturbances, a new dispersion relation is derived. It reduces to the Solberg-Hoieland criterion in the case without vertical stratification. It shows that, asymptotically, stable radial and vertical stratification cannot induce any linear instability; Keplerian flow is accordingly stable. Previous investigations strongly suggest that the so-called bypass concept of turbulence (i.e., that fine-tuned disturbances of any inviscid smooth shear flow can reach arbitrarily large transient growth) can also be applied to Keplerian disks. We present an analysis of this process for three-dimensional plane-wave disturbances comoving with the shear flow of a general rotating shear flow under combined stable radial and vertical rotation. We demonstrate that large transient growth occurs for K{sub 2}/k{sub 1} >> 1 and k{sub 3} = 0 or k{sub 1} {approx} k{sub 3}, where k{sub 1}, K{sub 2}, and k{sub 3} are the azimuthal, radial, and vertical components of the initial wave vector, respectively. By using a generalized ''wave-vortex'' decomposition of the disturbance, we show that the large transient energy growth in a Keplerian disk is mainly generated by the transient dynamics of the vortex mode. The analysis of the power spectrum of total (kinetic+potential) energy in the azimuthal or vertical directions shows that the contribution coming from the vortex mode is dominant at large scales, while the contribution coming from the wave mode is important at small scales. These findings may be confirmed by appropriate numerical simulations in the high Reynolds number regime.

Salhi, A. [Departement de Physique, Faculte des Sciences de Tunis, 1060 Tunis (Tunisia); Lehner, T. [LUTH, UMR 8102 CNRS, Observatoire de Paris-Meudon, 5 place de Janssen, F-92195 Meudon (France); Godeferd, F.; Cambon, C. [Laboratoire de Mecanique des Fluides et d'Acoustique, Ecole Centrale de Lyon, Universite de Lyon, UMR 5509, CNRS, INSA, UCB, F-69134 Ecully Cedex (France)

2013-07-10T23:59:59.000Z

447

Over Core Stress | Open Energy Information  

Open Energy Info (EERE)

Over Core Stress Over Core Stress Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Over Core Stress Details Activities (1) Areas (1) Regions (0) NEPA(0) Exploration Technique Information Exploration Group: Lab Analysis Techniques Exploration Sub Group: Rock Lab Analysis Parent Exploration Technique: Rock Lab Analysis Information Provided by Technique Lithology: Stratigraphic/Structural: Hydrological: Thermal: Dictionary.png Over Core Stress: No definition has been provided for this term. Add a Definition Related Techniques Rock Lab Analysis Core Analysis Cuttings Analysis Isotopic Analysis- Rock Over Core Stress Paleomagnetic Measurements Petrography Analysis Rock Density X-Ray Diffraction (XRD) X-Ray Fluorescence (XRF) References Page Area Activity Start Date Activity End Date Reference Material

448

Intermediate wavelength magnetic anomalies over ocean basins  

SciTech Connect (OSTI)

We have examined three very long magnetic field profiles taken over ocean basins for the presence of intermediate wavelength magnetic anomalies. One profile was from the Atlantic Ocean in the Transatlantic Geotraverse area, one ran along latitude 35/sup 0/S in the SE Pacific, and one ran along 150/sup 0/W in the Pacific. All three profiles show the presence of intermediate wavelength (65--1500 km) magnetic anomalies generated in the crust or upper mantle. The analysis of magnetic field power spectra shows that the core field becomes unimportant at about a wavelength of 1500 km. Sea floor spreading anomalies should produce a maximum in power at about a wavelength of 65 km. Between these two wavelengths there should be a minimum in power which is not seen on observed records. Inverting the anomalous field to obtain some idea of the magnetization necessary to explain these intermediate wavelength magnetic anomalies shows that values of magnetization in excess of 1 A m/sup -1/ are needed if the magnetized layer is as thick as the ocean crust. Alternatively, rather large thicknesses of upper mantle material with lower intensities of magnetization need to be used. The reason why such magnetization variations exist is not known. It can be shown that upward continuation of the magnetic anomaly signature to an altitude of 350 km (about the perihelion altitude of MAGSAT) will produce anomalies up to 10 nT in amplitude. These should be capable of being seen by MAGSAT, and thus allow us to determine the spatial arrangement of the intermediate wavelength anomalies and hence, hopefully, a clue as to their origin.

Harrison, C.G.A.; Carle, H.M.

1981-12-10T23:59:59.000Z

449

Interconversion of dark soliton and Josephson vortex in a quasi-1D long Bose Josephson junction  

E-Print Network [OSTI]

Dark soliton (DS) and Josephson vortex (JV) in quasi-1D long Bose Josephson junction (BJJ) can be interconverted by tuning Josephson coupling. Rates of the interconversion as well as of the thermally activated phase-slip effect, resulting in the JV switching its vorticity, have been evaluated. The role of quantum phase-slip in creating superposition of JVs with opposite vorticities as a qubit is discussed as well. Utilization of the JV for controlled and coherent transfer of atomic Bose-Einstein condensate (BEC) is suggested.

V. M. Kaurov; A. B. Kuklov

2004-06-15T23:59:59.000Z

450

Vortex states in a binary mixture of Bose-Einstein condensates  

Science Journals Connector (OSTI)

The vortex configurations in the Bose-Einstein condensate of a mixture of two different spin states |F=1,mf=-1? and |2,1? of 87Rb atoms corresponding to the recent experiments by Matthews et al. [Phys. Rev. Lett. 83, 2498 (1999)] are considered in the framework of the Thomas-Fermi approximation as functions of N2/N1, where N1 is the number of atoms in the state |1,-1? and N2 in the state |2,1?. Ranges of this ratio are determined within which the various configurations of the binary condensate are stable.

S. T. Chui; V. N. Ryzhov; E. E. Tareyeva

2001-01-11T23:59:59.000Z

451

Large Pitch Hollow Core Honeycomb Fiber  

Science Journals Connector (OSTI)

A new kind of hollow core photonic crystal fiber (HC-PCF) for broadband guidance is introduced. Structural and optical properties of a fabricated example are detailed.

Beaudou, Benoît; Couny, François; Benabid, Fetah; Roberts, Peter John

452

magnets2  

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

II II Painless Physics Articles BEAM COOLING August 2, 1996 By Leila Belkora, Office of Public Affairs ACCELERATION August 16, 1996 By Dave Finley, Accelerator Division Head RF August 30, 1996 By Pat Colestock, Accelerator Division FIXED TARGET PHYSICS September 20, 1996 By Peter H. Garbincius, Physics Section FIXED TARGET PHYSICS PART DEUX October 16, 1996 By Peter H. Garbincius, Physics Section and Leila Belkora, Office of Public Affaris CROSS SECTION November 1, 1996 By Doreen Wackeroth, Theoretical Physics Edited by Leila Belkora, Office of Public Affaris MAGNETS PART I November 15, 1996 By Hank Glass, Technical Support Section Edited by Donald Sena, Office of Public Affairs MAGNETS PART II January 10, 1997 By Hank Glass, Technical Support Section Edited by Donald Sena, Office of Public Affairs

453

Femtosecond laser fabrication of micro and nano-disks in single layer graphene using vortex Bessel beams  

SciTech Connect (OSTI)

We report the fabrication of micro and nano-disks in single layer chemical vapor deposition graphene on glass substrate using femtosecond laser ablation with vortex Bessel beams. The fabricated graphene disks with diameters ranging from 650?nm to 4??m were characterized by spatially resolved micro-Raman spectroscopy. The variation of ablation threshold was investigated as a function of the number of pulses showing an incubation effect. A very high degree of size control of the fabricated graphene disks is enabled using a sequence of femtosecond pulses with different vortex orders.

Wetzel, Benjamin, E-mail: benjamin.wetzel@femto-st.fr; Xie, Chen; Lacourt, Pierre-Ambroise; Dudley, John M.; Courvoisier, Francois [Département d'Optique P.M. Duffieux, Institut FEMTO-ST, UMR–6174 CNRS, Université de Franche-Comté, 25030 Besançon (France)] [Département d'Optique P.M. Duffieux, Institut FEMTO-ST, UMR–6174 CNRS, Université de Franche-Comté, 25030 Besançon (France)

2013-12-09T23:59:59.000Z

454

Magnetic Reconnection  

SciTech Connect (OSTI)

We review the fundamental physics of magnetic reconnection in laboratory and space plasmas, by discussing results from theory, numerical simulations, observations from space satellites, and the recent results from laboratory plasma experiments. After a brief review of the well-known early work, we discuss representative recent experimental and theoretical work and attempt to interpret the essence of significant modern findings. In the area of local reconnection physics, many significant findings have been made with regard to two- uid physics and are related to the cause of fast reconnection. Profiles of the neutral sheet, Hall currents, and the effects of guide field, collisions, and micro-turbulence are discussed to understand the fundamental processes in a local reconnection layer both in space and laboratory plasmas. While the understanding of the global reconnection dynamics is less developed, notable findings have been made on this issue through detailed documentation of magnetic self-organization phenomena in fusion plasmas. Application of magnetic reconnection physics to astrophysical plasmas is also brie y discussed.

Masaaki Yamada, Russell Kulsrud and Hantao Ji

2009-09-17T23:59:59.000Z

455

PROTOSTELLAR ACCRETION FLOWS DESTABILIZED BY MAGNETIC FLUX REDISTRIBUTION  

SciTech Connect (OSTI)

Magnetic flux redistribution lies at the heart of the problem of star formation in dense cores of molecular clouds that are magnetized to a realistic level. If all of the magnetic flux of a typical core were to be dragged into the central star, the stellar field strength would be orders of magnitude higher than the observed values. This well-known magnetic flux problem can in principle be resolved through non-ideal MHD effects. Two-dimensional (axisymmetric) calculations have shown that ambipolar diffusion, in particular, can transport magnetic flux outward relative to matter, allowing material to enter the central object without dragging the field lines along. We show through simulations that such axisymmetric protostellar accretion flows are unstable in three dimensions to magnetic interchange instability in the azimuthal direction. The instability is driven by the magnetic flux redistributed from the matter that enters the central object. It typically starts to develop during the transition from the prestellar phase of star formation to the protostellar mass accretion phase. In the latter phase, the magnetic flux is transported outward mainly through advection by strongly magnetized low-density regions that expand against the collapsing inflow. The tussle between the gravity-driven infall and magnetically driven expansion leads to a highly filamentary inner accretion flow that is more disordered than previously envisioned. The efficient outward transport of magnetic flux by advection lowers the field strength at small radii, making the magnetic braking less efficient and the formation of rotationally supported disks easier in principle. However, we find no evidence for such disks in any of our rotating collapse simulations. We conclude that the inner protostellar accretion flow is shaped to a large extent by the flux redistribution-driven magnetic interchange instability. How disks form in such an environment is unclear.

Krasnopolsky, Ruben; Shang, Hsien [Academia Sinica, Institute of Astronomy and Astrophysics, Taipei, Taiwan (China); Li Zhiyun; Zhao Bo [University of Virginia, Astronomy Department, Charlottesville (United States)

2012-09-20T23:59:59.000Z

456

Origin of the Core Francis Nimmo  

E-Print Network [OSTI]

Origin of the Core Francis Nimmo Dept. Earth Sciences, University of California, Santa Cruz F. Nimmo, Dept. Earth Sciences, University of California, Santa Cruz, CA 95064, USA (fnimmo@es.ucsc.edu), tel. 831-459-1783, fax. 831-459-3074 1 #12;Origin of the Core All major bodies of the inner solar

Nimmo, Francis

457

Idealized Test Cases for Dynamical Core Experiments  

E-Print Network [OSTI]

Idealized Test Cases for Dynamical Core Experiments Christiane Jablonowski (University of Michigan-13/2006 #12;Motivation · Test cases for 3D dynamical cores on the sphere ­ are hard to find in the literature groups ­ lack standardized & easy-to-use analysis techniques · Idea: Establish a collection of test cases

Jablonowski, Christiane

458

Experto Universitario Java Sesin 1: Spring core  

E-Print Network [OSTI]

Enterprise Spring © 2012-2013 Depto. Ciencia de la Computación e IA Spring core Puntos a tratar 2 #12;Experto Universitario Java Enterprise Spring © 2012-2013 Depto. Ciencia de la Computación e IA;Experto Universitario Java Enterprise Spring © 2012-2013 Depto. Ciencia de la Computación e IA Spring core

Escolano, Francisco

459

Module Handbook Core Univ. of Oldenburg  

E-Print Network [OSTI]

· Mechanical and Electrical Systems of the WEC Content: Energy conversion process in Wind Turbines · Wind/EUREC Course 2008/2009 #12;EUREC Core Courses at University of Oldenburg, 1st Semester Wind Energy Module Module Description: Wind Energy Field: Core Oldenburg Courses: Wind Energy Wind Energy

Habel, Annegret

460

UNL Core for Applied Genomics and Ecology  

E-Print Network [OSTI]

UNL Core for Applied Genomics and Ecology Bioinformatics training Roche 454 GS-FLX Registration, Microbiomes, Variant Analysis, Whole Genomes, Transcriptomes Data Analysis and Statistics CAGE database and employer. University of Nebraska-Lincoln*Core for Applied Genomics and Ecology* 323 Filley Hall *Lincoln

Farritor, Shane

Note: This page contains sample records for the topic "magnetic vortex core" from the National Library of EnergyBeta (NLEBeta).
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461

Achieving high flux amplification in a gun-driven, flux-core spheromak  

Science Journals Connector (OSTI)

A new means of operating flux-core spheromaks with possibly increased stability, confinement and pulse length is analysed by a resistive magnetohydrodynamic (MHD) model. High amplification of the bias poloidal flux, required to minimize ohmic losses, is achieved by reducing the bias rapidly in a plasma formed at a lower amplification. The plasma separatrix is predicted to expand and incorporate the removed bias flux maintaining the total poloidal flux within the spheromak's flux-conserving wall. MHD energy on open magnetic field lines is reduced, reducing magnetic fluctuation levels. A means of experimental verification is suggested that may point the way to fusion-relevant spheromaks.

E.B. Hooper; D.N. Hill; H.S. McLean; C.A. Romero-Talamás; R.D. Wood

2007-01-01T23:59:59.000Z

462

Copper laser modulator driving assembly including a magnetic compression laser  

DOE Patents [OSTI]

A laser modulator (10) having a low voltage assembly (12) with a plurality of low voltage modules (14) with first stage magnetic compression circuits (20) and magnetic assist inductors (28) with a common core (91), such that timing of the first stage magnetic switches (30b) is thereby synchronized. A bipolar second stage of magnetic compression (42) is coupled to the low voltage modules (14) through a bipolar pulse transformer (36) and a third stage of magnetic compression (44) is directly coupled to the second stage of magnetic compression (42). The low voltage assembly (12) includes pressurized boxes (117) for improving voltage standoff between the primary winding assemblies (34) and secondary winding (40) contained therein.

Cook, Edward G. (Livermore, CA); Birx, Daniel L. (Oakley, CA); Ball, Don G. (Livermore, CA)

1994-01-01T23:59:59.000Z

463

MAGNETIC FIELD STRUCTURE AROUND LOW-MASS CLASS 0 PROTOSTARS: B335, L1527, AND IC348-SMM2  

SciTech Connect (OSTI)

We report new 350 {mu}m polarization observations of the thermal dust emission from the cores surrounding the low-mass, Class 0 young stellar objects L1527, IC348-SMM2, and B335. We have inferred magnetic field directions from these observations and have used them together with results in the literature to determine whether magnetically regulated core-collapse and star formation models are consistent with the observations. These models predict a pseudo-disk with its symmetry axis aligned with the core magnetic field. The models also predict a magnetic field pinch structure on a scale less than or comparable to the infall radii for these sources. In addition, if the core magnetic field aligns (or nearly aligns) the core rotation axis with the magnetic field before core collapse, then the models predict the alignment (or near alignment) of the overall pinch field structure with the bipolar outflows in these sources. We show that if one includes the distorting effects of bipolar outflows on magnetic fields, then in general the observational results for L1527 and IC348-SMM2 are consistent with these magnetically regulated models. We can say the same for B335 only if we assume that the distorting effects of the bipolar outflow on the magnetic fields within the B335 core are much greater than for L1527 and IC348-SMM2. We show that the energy densities of the outflows in all three sources are large enough to distort the magnetic fields predicted by magnetically regulated models.

Davidson, J. A. [School of Physics, University of Western Australia, 35 Stirling Hwy, Crawley, WA 6009 (Australia); Novak, G.; Matthews, T. G. [Department of Physics and Astronomy, Northwestern University, 2131 Tech Dr., Evanston, IL 60208 (United States); Matthews, B. [Herzberg Institute of Astrophysics, National Research Council of Canada, 5071 West Saanich Road, Victoria, BC, V9E 2E7 (Canada); Goldsmith, P. F.; Chapman, N. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr., Ms 264-782, Pasadena, CA 91109 (United States); Volgenau, N. H. [California Institute of Technology, Owens Valley Radio Observatory, Big Pine, CA 93513 (United States); Vaillancourt, J. E. [Universities Space Research Association, SOFIA, NASA Ames Research Center, MS 211-3, Moffett Field, CA 94035-0001 (United States); Attard, M. [Laboratoire AIM, CEA/DSM-CNRS-Universite Paris Diderot, IRFU/Service d'Astrophysique, CEA Saclay, Orme des Merisiers, 91191 Gif-sur-Yvette (France)

2011-05-10T23:59:59.000Z

464

Magnetic Reconnection in Astrophysical and  

E-Print Network [OSTI]

Magnetic Reconnection in Astrophysical and Laboratory Plasmas Ellen G. Zweibel1 and Masaaki Yamada2 astrophysics, magnetic fields, magnetic reconnection Abstract Magnetic reconnection is a topological rearrangement of magnetic field that converts magnetic energy to plasma energy. Astrophysical flares, from

465

Core File Settings | Argonne Leadership Computing Facility  

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

Core File Settings Core File Settings The following environment variables control core file creation and contents. Specify regular (non-script) jobs using the qsub argument --env (Note: two dashes). Specify script jobs (--mode script) using the --envs (Note: two dashes) or --exp_env (Note: two dashes) options of runjob. For additional information about setting environment variables in your job, visit http://www.alcf.anl.gov/user-guides/running-jobs#environment-variables. Generation The following environment variables control conditions of core file generation and naming: BG_COREDUMPONEXIT=1 Creates a core file when the application exits. This is useful when the application performed an exit() operation and the cause and location of the exit() is not known. BG_COREDUMPONERROR=1

466

Electronic Structure and Magnetism in Diluted Magnetic Semiconductors  

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

Electronic Structure and Magnetism in Diluted Magnetic Semiconductors Electronic Structure and Magnetism in Diluted Magnetic Semiconductors Print Wednesday, 29 November 2006 00:00...

467

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...

468

THREE-DIMENSIONAL SIMULATIONS OF MAGNETOHYDRODYNAMIC WAVES IN MAGNETIZED SOLAR ATMOSPHERE  

SciTech Connect (OSTI)

We present results of three-dimensional numerical simulations of magnetohydrodynamic (MHD) wave propagation in a solar magnetic flux tube. Our study aims at understanding the properties of a range of MHD wave modes generated by different photospheric motions. We consider two scenarios observed in the lower solar photosphere, namely, granular buffeting and vortex-like motion, among the simplest mechanism for the generation of waves within a strong, localized magnetic flux concentration. We show that granular buffeting is likely to generate stronger slow and fast magnetoacoustic waves as compared to swirly motions. Correspondingly, the energy flux transported differs as a result of the driving motions. We also demonstrate that the waves generated by granular buffeting are likely to manifest in stronger emission in the chromospheric network. We argue that different mechanisms of wave generation are active during the evolution of a magnetic element in the intergranular lane, resulting in temporally varying emission at chromospheric heights.

Vigeesh, G. [Department of Astronomy, New Mexico State University, Las Cruces, NM (United States); Fedun, V.; Erdelyi, R. [SP2RC, Department of Applied Mathematics, University of Sheffield (United Kingdom); Hasan, S. S. [Indian Institute of Astrophysics, Bangalore (India)

2012-08-10T23:59:59.000Z

469

EARLIEST STAGES OF PROTOCLUSTER FORMATION: SUBSTRUCTURE AND KINEMATICS OF STARLESS CORES IN ORION  

SciTech Connect (OSTI)

We study the structure and kinematics of nine 0.1 pc scale cores in Orion with the IRAM 30 m telescope and at higher resolution eight of the cores with CARMA, using CS(2-1) as the main tracer. The single-dish moment zero maps of the starless cores show single structures with central column densities ranging from 7 to 42 Multiplication-Sign 10{sup 23} cm{sup -2} and LTE masses from 20 M{sub Sun} to 154 M{sub Sun }. However, at the higher CARMA resolution (5''), all of the cores except one fragment into 3-5 components. The number of fragments is small compared to that found in some turbulent fragmentation models, although inclusion of magnetic fields may reduce the predicted fragment number and improve the model agreement. This result demonstrates that fragmentation from parsec-scale molecular clouds to sub-parsec cores continues to take place inside the starless cores. The starless cores and their fragments are embedded in larger filamentary structures, which likely played a role in the core formation and fragmentation. Most cores show clear velocity gradients, with magnitudes ranging from 1.7 to 14.3 km s{sup -1} pc{sup -1}. We modeled one of them in detail, and found that its spectra are best explained by a converging flow along a filament toward the core center; the gradients in other cores may be modeled similarly. We infer a mass inflow rate of {approx}2 Multiplication-Sign 10{sup -3} M{sub Sun} yr{sup -1}, which is in principle high enough to overcome radiation pressure and allow for massive star formation. However, the core contains multiple fragments, and it is unclear whether the rapid inflow would feed the growth of primarily a single massive star or a cluster of lower mass objects. We conclude that fast, supersonic converging flow along filaments play an important role in massive star and cluster formation.

Lee, Katherine; Looney, Leslie W. [Department of Astronomy, University of Illinois, Urbana, IL 61801 (United States); Schnee, Scott [National Radio Astronomy Observatory, Charlottesville, VA 22903 (United States); Li Zhiyun [Astronomy Department, University of Virginia, Charlottesville, VA 22904 (United States)

2013-08-01T23:59:59.000Z

470

Effect of magnetic field on the photon detection in thin superconducting meander structures  

Science Journals Connector (OSTI)

We have studied the influence of an externally applied magnetic field on the photon and dark count rates of meander-type niobium nitride superconducting nanowire single-photon detectors. Measurements have been performed at a temperature of 4.2 K, and magnetic fields up to 250 mT have been applied perpendicularly to the meander plane. While photon count rates are field independent at weak applied fields, they show a strong dependence at fields starting from approximately ±25 mT. This behavior, as well as the magnetic field dependence of the dark count rates, is in good agreement with the recent theoretical model of vortex-assisted photon detection and spontaneous vortex crossing in narrow superconducting lines. However, the local reduction of the superconducting free energy due to photon absorption, which is the fitting parameter in the model, increases much slower with the photon energy than the model predicts. Furthermore, changes in the free-energy during photon counts and dark counts depend differently on the current that flows through the meander. This indicates that photon counts and dark counts occur in different parts of the meander.

R. Lusche; A. Semenov; Y. Korneeva; A. Trifonov; A. Korneev; G. Gol'tsman; H.-W. Hübers

2014-03-19T23:59:59.000Z

471

Platinum-Maghemite Core-Shell Nanoparticles Using a Sequential Synthesis  

SciTech Connect (OSTI)

OAK-B135 Pt{at}Fe2O3 core-shell nanoparticles have been made using a sequential synthetic method. Platinum nanoparticles were synthesized via reduction of platinum acetylacetonate in octyl ether, and layers of iron oxide were subsequently deposited on the surface of Pt nanoparticles through thermal decomposition of iron pentacarbonyl. The core-shell nanoparticles were characterized by powder X-ray diffraction, high-resolution transmission electron microscopy, and X-ray photoemission spectroscopy. Thickness of the shell can be controlled by changing concentrations of the reactants and the reaction conditions. These Pt{at}Fe2O3 core-shell nanoparticles could have potential applications in catalysis and as precursors for making property-tunable magnetic nanoparticles, thin films, and nanocomposites.

Teng, X.; Black, D.; Watkins, N.J.; Gao, Y.; Yang, H.

2003-01-11T23:59:59.000Z

472

Knot energy in unstretching ergodic magnetic flux tubes  

E-Print Network [OSTI]

Recently Titov et al [ApJ \\textbf{693},(2009) and ApJ (2007)] have made use of a covariant model to investigate magnetic reconnection of astrophysical plasmas. Earlier R Ricca [Phys Rev A (1991)] has used another covariant formalism, to investigated vortex filaments and solitons. This formalism, called Ricci rotation coefficients (RRC), is applied here, to the Chui and Moffatt [PRSA (1995)] knotted magnetic flux tube (MFT) Riemann metric in the case of vanishing stretch. It is shown that, the vanishing of some components of the (RRC) leads to unstretching knotted tubes. Computing of magnetic knot energy in terms of the RCC, shows that, uniform, unstretching and constant cross-section tubes leads to a marginal dynamo action over magnetic surfaces. Recent investigation on the role of stretching in plasma dynamo action showed that in diffusive media [Phys Plasma \\textbf{14} (2008)], unstretching unknotted tubes would not support fast dynamo action. This result was generalized here to much more general knotted MF...

de Andrade, Garcia

2009-01-01T23:59:59.000Z

473

Grain Alignment by Radiation in Dark Clouds and Cores  

E-Print Network [OSTI]

We study alignment of grains by radiative torques. We found steep rise of radiative torque efficiency as grain size increases. This allows larger grains that are known to exist within molecular clouds to be aligned by the attenuated and reddened interstellar radiation field. In particular, we found that, even deep inside giant molecular clouds, e.g. at optical depths corresponding to less than Av of 10 large grains can still be aligned by radiative torque. This means that, contrary to earlier claims, far-infrared/submillimeter polarimetry provides a reliable tool to study magnetic fields of pre-stellar cores. Our results show that the grain size distribution is important for determining the relation between the degree of polarization and intensity.

J. Cho; A. Lazarian

2005-05-28T23:59:59.000Z

474

Quantum Dissociation of a Vortex-Antivortex Pair in a Long Josephson Junction M.V. Fistul,1  

E-Print Network [OSTI]

Quantum Dissociation of a Vortex-Antivortex Pair in a Long Josephson Junction M.V. Fistul,1 A VAV pair manifests itself in a switching of the Josephson junction from the superconducting biased single Josephson junctions (JJs), various SQUIDs, and small Josephson junction arrays, contain

Wallraff, Andreas

475

Tracking Waves and Vortex Nucleation in Excitable Systems with Anomalous Dispersion N. Manz, C.T. Hamik, and O. Steinbock  

E-Print Network [OSTI]

Tracking Waves and Vortex Nucleation in Excitable Systems with Anomalous Dispersion N. Manz, C obtained from a chemical reaction-diffusion system in which wave propagation is limited to a finite band of wavelengths and in which no solitary pulses exist. Wave patterns increase their size through repeated

Steinbock, Oliver

476

Quantum Hasimoto transformation and nonlinear waves on a superfluid vortex filament under the quantum local induction approximation  

E-Print Network [OSTI]

The Hasimoto transformation between the classical LIA (local induction approximation, a model approximating the motion of a thin vortex filament) and the nonlinear Schr\\"odinger equation (NLS) has proven very useful in the past, since it allows one to construct new solutions to the LIA once a solution to the NLS is known. In the present paper, the quantum form of the LIA (which includes mutual friction effects) is put into correspondence with a type of complex nonlinear dispersive partial differential equation (PDE) with cubic nonlinearity (similar in form to a Ginsburg-Landau equation, with additional nonlinear terms). Transforming the quantum LIA in such a way enables one to obtain quantum vortex filament solutions once solutions to this dispersive PDE are known. From our quantum Hasimoto transformation, we determine the form and behavior of Stokes waves and a standing 1-soliton solution under normal and binormal friction effects. The soliton solution on a quantum vortex filament is a natural generalization of the classical 1-soliton solution constructed mathematically by Hasimoto (which motivated subsequent real-world experiments). The quantum Hasimoto transformation is useful when normal fluid velocity is relatively weak, so for the case where the normal fluid velocity is dominant we resort to other approaches. We consider the dynamics of the tangent vector to the vortex filament directly from the quantum LIA, and this approach, while less elegant than the quantum Hasimoto transformation, enables us to study waves primarily driven by the normal fluid velocity.

Robert A. Van Gorder

2014-11-19T23:59:59.000Z

477

Energy Losses Due to Vortex Shedding from the Lower Edge of a Vertical Plate Attacked by Surface Waves  

Science Journals Connector (OSTI)

...Vertical Plate Attacked by Surface Waves M. Stiassnie E. Naheer Irina Boguslavsky...The ratio between the flux of the energy taken out by the vortex generation process , and the incoming wave energy flux , is shown to be given by where...

1984-01-01T23:59:59.000Z

478

Superconducting magnet  

DOE Patents [OSTI]

A superconducting magnet designed to produce magnetic flux densities of the order of 4 to 5 Webers per square meter is constructed by first forming a cable of a plurality of matrixed superconductor wires with each wire of the plurality insulated from each other one. The cable is shaped into a rectangular cross-section and is wound with tape in an open spiral to create cooling channels. Coils are wound in a calculated pattern in saddle shapes to produce desired fields, such as dipoles, quadrupoles, and the like. Wedges are inserted between adjacent cables as needed to maintain substantially radial placement of the long dimensions of cross sections of the cables. After winding, individual strands in each of the cables are brought out to terminals and are interconnected to place all of the strands in series and to maximize the propagation of a quench by alternating conduction from an inner layer to an outer layer and from top half to bottom half as often as possible. Individual layers are separated from others by spiraled aluminum spacers to facilitate cooling. The wound coil is wrapped with an epoxy tape that is cured by heat and then machined to an interference fit with an outer aluminum pipe which is then affixed securely to the assembled coil by heating it to make a shrink fit. In an alternate embodiment, one wire of the cable is made of copper or the like to be heated externally to propagate a quench.

Satti, John A. (Naperville, IL)

1980-01-01T23:59:59.000Z

479

Improved superconducting magnet wire  

DOE Patents [OSTI]

This invention is directed to a superconducting tape or wire composed of alternating layers of copper and a niobium-containing superconductor such as niobium of NbTi, Nb/sub 3/Sn or Nb/sub 3/Ge. In general, each layer of the niobium-containing superconductor has a thickness in the range of about 0.05 to 1.5 times its coherence length (which for Nb/sub 3/Si is 41 A) with each copper layer having a thickness in the range of about 170 to 600 A. With the use of very thin layers of the niobium composition having a thickness within the desired range, the critical field (H/sub c/) may be increased by factors of 2 to 4. Also, the thin layers of the superconductor permit the resulting tape or wire to exhibit suitable ductility for winding on a magnet core. These compositions are also characterized by relatively high values of critical temperature and therefore will exhibit a combination of useful properties as superconductors.

Schuller, I.K.; Ketterson, J.B.

1983-08-16T23:59:59.000Z

480

Heat transfer in sunspot penumbrae. Origin of dark-cored penumbral filaments  

E-Print Network [OSTI]

Context: Observations at 0.1" have revealed the existence of dark cores in the bright filaments of sunspot penumbrae. Expectations are high that such dark-cored filaments are the basic building blocks of the penumbra, but their nature remains unknown. Aims: We investigate the origin of dark cores in penumbral filaments and the surplus brightness of the penumbra. To that end we use an uncombed penumbral model. Methods: The 2D stationary heat transfer equation is solved in a stratified atmosphere consisting of nearly horizontal magnetic flux tubes embedded in a stronger and more vertical field. The tubes carry an Evershed flow of hot plasma. Results: This model produces bright filaments with dark cores as a consequence of the higher density of the plasma inside the tubes, which shifts the surface of optical depth unity toward higher (cooler) layers. Our calculations suggest that the surplus brightness of the penumbra is a natural consequence of the Evershed flow, and that magnetic flux tubes about 250 km in diameter can explain the morphology of sunspot penumbrae.

B. Ruiz Cobo; L. R. Bellot Rubio

2008-10-07T23:59:59.000Z

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