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Sample records for strong magnetic field

  1. Strong Magnetic Field Characterisation

    DTIC Science & Technology

    2012-04-01

    coils were driven by a pulsed-power system to generate the fields. All the sources were characterised through a series of measurements and modelling... generated for the coils. Options for further investigation were provided. UNCLASSIFIED UNCLASSIFIED This...investigation. The desired field strength was based on assessments [1] from preliminary magnetohydrodynamic ( MHD ) modelling and while not achievable by

  2. Thermodynamical instabilities under strong magnetic fields

    NASA Astrophysics Data System (ADS)

    Chen, Y. J.

    2017-03-01

    The thermodynamical instabilities of low densities in the n p matter and n p e matter are studied within several relativistic nuclear models under some values of magnetic fields. The results are compared between each other and the effects of the symmetry energy slope at saturation density on the instability are investigated. The instability regions can exhibit bands due to the presence of Landau levels for very strong magnetic fields of the order of 1017 G, while for weaker magnetic fields, the bands are replaced by many diffused or scattered pieces. It also shows that the proton fraction in the inner crust of neutron stars may be complex under strong magnetic fields.

  3. Strong intrinsic mixing in vortex magnetic fields.

    PubMed

    Martin, James E; Shea-Rohwer, Lauren; Solis, Kyle J

    2009-07-01

    We report a method of magnetic mixing wherein a "vortex" magnetic field applied to a suspension of magnetic particles creates strong homogeneous mixing throughout the fluid volume. Experiments designed to elucidate the microscopic mechanism of mixing show that the torque is quadratic in the field, decreases with field frequency, and is optimized at a vortex field angle of approximately 55 degrees . Theory and simulations indicate that the field-induced formation of volatile particle chains is responsible for these phenomena. This technique has applications in microfluidic devices and is ideally suited to applications such as accelerating the binding of target biomolecules to biofunctionalized magnetic microbeads.

  4. Decay of Resonaces in Strong Magnetic Field

    NASA Astrophysics Data System (ADS)

    Filip, Peter

    2015-08-01

    We suggest that decay properties (branching ratios) of hadronic resonances may become modified in strong external magnetic field. The behavior of K±*, K0* vector mesons as well as Λ* (1520) and Ξ0* baryonic states is considered in static fields 1013-1015 T. In particular, n = 0 Landau level energy increase of charged particles in the external magnetic field, and the interaction of hadron magnetic moments with the field is taken into account. We suggest that enhanced yield of dileptons and photons from ρ0(770) mesons may occur if strong decay channel ρ0 → π+π- is significantly suppressed. CP - violating π+π- decays of pseudoscalar ηc and η(547) mesons in the magnetic field are discussed, and superpositions of quarkonium states ηc,b and χc,b(nP) with Ψ(nS), ϒ(nS) mesons in the external field are considered.

  5. MRS photodiode in strong magnetic field

    SciTech Connect

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

    2004-12-01

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

  6. Quantum processes in strong magnetic fields

    NASA Technical Reports Server (NTRS)

    Canuto, V.

    1975-01-01

    Quantum-mechanical processes that occur in a piece of matter embedded in a magnetic field with a strength of the order of 10 to the 13th power G are described which either are entirely due to the presence of the field or become modified because of it. The conversion of rotational energy into electromagnetic energy in pulsars is analyzed as a mechanism for producing such a field, and it is shown that a strong magnetic field is not sufficient for quantum effects to play a significant role; in addition, the density must be adjusted to be as low as possible. The pressure and energy density of a free electron gas in a uniform magnetic field are evaluated, neutron beta-decay in the presence of a strong field is examined, and the effect of such a field on neutrino reactions is discussed. The thermal history of a neutron star is studied, and it is concluded that a strong magnetic field helps to increase the cooling rate of the star by producing new channels through which neutrinos can carry away energy.

  7. Quantum processes in strong magnetic fields

    NASA Technical Reports Server (NTRS)

    Canuto, V.

    1975-01-01

    Quantum-mechanical processes that occur in a piece of matter embedded in a magnetic field with a strength of the order of 10 to the 13th power G are described which either are entirely due to the presence of the field or become modified because of it. The conversion of rotational energy into electromagnetic energy in pulsars is analyzed as a mechanism for producing such a field, and it is shown that a strong magnetic field is not sufficient for quantum effects to play a significant role; in addition, the density must be adjusted to be as low as possible. The pressure and energy density of a free electron gas in a uniform magnetic field are evaluated, neutron beta-decay in the presence of a strong field is examined, and the effect of such a field on neutrino reactions is discussed. The thermal history of a neutron star is studied, and it is concluded that a strong magnetic field helps to increase the cooling rate of the star by producing new channels through which neutrinos can carry away energy.

  8. Firefly flashing under strong static magnetic field.

    PubMed

    Barua, Anurup Gohain; Iwasaka, Masakazu; Miyashita, Yuito; Kurita, Satoru; Owada, Norio

    2012-02-01

    Firefly flashing has been the subject of numerous scientific investigations. Here we present in vivo flashes from male specimens of three species of fireflies-two Japanese species Luciola cruciata, Luciola lateralis and one Indian species Luciola praeusta-positioned under a superconducting magnet. When the OFF state of the firefly becomes long after flashing in an immobile state under the strong static magnetic field of strength 10 Tesla for a long time, which varies widely from species to species as well as from specimen to specimen, the effect of the field becomes noticeable. The flashes in general are more rapid, and occasionally overlap to produce broad compound flashes. We present the broadest flashes recorded to date, and propose that the strong static magnetic field affects the neural activities of fireflies, especially those in the spent up or 'exhausted' condition.

  9. Molecular systems in a strong magnetic field

    NASA Astrophysics Data System (ADS)

    Turbiner, Alexander V.

    2007-04-01

    Brief overview of one-two electron molecular systems made out of protons and/or α-particles in a strong magnetic field B≤4.414×1013 G is presented. A particular emphasis is given to the one-electron exotic ions H 3 ++ (pppe), He 2 3+ (α α e) and to two-electron ionsH 3 + (pppee), He 2 ++ (α α ee). Quantitative studies in a strong magnetic field are very complicated technically. Novel approach to the few-electron Coulomb systems in magnetic field, which provides accurate results, based on variational calculus with physically relevant trial functions is briefly described.

  10. Charm production in a strong magnetic field

    SciTech Connect

    Machado, C. S.; Navarra, F. S.; Noronha, J.; Oliveira, E. G. de; Strickland, M.

    2014-11-11

    We discuss the effects of a strong magnetic field on B and D mesons, focusing on the changes of the energy levels and the masses of the bound states. Using the Color Evaporation Model we discuss the possible changes in the production of J/ψ and Υ. We briefly comment the recent experimental data.

  11. Bound states in a strong magnetic field

    SciTech Connect

    Machado, C. S.; Navarra, F. S.; Noronha, J.; Oliveira, E. G.; Ferreira Filho, L. G.

    2013-03-25

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

  12. Atoms and Molecules in Strong Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Schmelcher, P.; Cederbaum, L. S.

    Selected topics on atoms and molecules in strong magnetic fields are reviewed. The enormous progress made for the hydrogen atom in a magnetic field and its impact on different areas like, for example, modern semi-classics and dynamics of non-integrable systems as well as laser spectroscopy are outlined. Due to the non-separability of the centre of mass and electronic motion of atoms/molecules in magnetic fields a variety of two-body phenomena can be observed in highly excited systems. Examples are the classical diffusion of the centre of mass and the giant dipole states for crossed fields. For ions energy transfer processes lead to the so-called self-ionisation process. Magnetically induced crossovers for the ground states of atoms are investigated. The increasing complexity of the ground state behaviour of magnetically dressed multi-electron atoms due to changes of the spin polarisation as well as spatial orbitals is demonstrated. For molecules, both fundamental aspects as well as the electronic structure of few-electron diatomics are reviewed.

  13. Photoneutrino energy losses in strong magnetic fields.

    NASA Technical Reports Server (NTRS)

    Canuto, V.; Fassio-Canuto, L.

    1973-01-01

    Previously computed rates of energy losses (Petrosian et al., 1967) ignored the presence of strong magnetic fields, hence the change brought in when such a field (about 10 to the 12th to 10 to the 13th power G) is included is studied. The results indicate that for T about 10 to the 8th power K and densities rho of about 10,000 g/cu cm, the presence of a strong H field decreases the energy losses by at the most a factor between 10 and 100 in the region up to rho = 1,000,000 g/cu cm. At higher densities the neutrino emissivities are almost identical.

  14. Photoneutrino energy losses in strong magnetic fields.

    NASA Technical Reports Server (NTRS)

    Canuto, V.; Fassio-Canuto, L.

    1973-01-01

    Previously computed rates of energy losses (Petrosian et al., 1967) ignored the presence of strong magnetic fields, hence the change brought in when such a field (about 10 to the 12th to 10 to the 13th power G) is included is studied. The results indicate that for T about 10 to the 8th power K and densities rho of about 10,000 g/cu cm, the presence of a strong H field decreases the energy losses by at the most a factor between 10 and 100 in the region up to rho = 1,000,000 g/cu cm. At higher densities the neutrino emissivities are almost identical.

  15. Free oscillations of magnetic fluid in strong magnetic field

    NASA Astrophysics Data System (ADS)

    Polunin, V. M.; Ryapolov, P. A.; Platonov, V. B.; Kuz'ko, A. E.

    2016-05-01

    The paper presents the esults of measuring the elastic parameters of an oscillatory system (coefficient of pondermotive elasticity, damping factor, and oscillation frequency) whose viscous inertial element is represented by a magnetic fluid confined in a tube by magnetic levitation in a strong magnetic field. The role of elasticity is played by the pondermotive force acting on thin layers at the upper and lower ends of the fluid column. It is shown that, by measuring the elastic oscillation frequencies of the magnetic fluid column, it is possible to develop a fundamentally new absolute method for determining the saturation magnetization of a magnetic colloid.

  16. Compton scattering in strong magnetic fields

    NASA Technical Reports Server (NTRS)

    Daugherty, Joseph K.; Harding, Alice K.

    1986-01-01

    The relativistic cross section for Compton scattering by electrons in strong magnetic fields is derived. The results confirm and extend earlier work which has treated only transitions to the lowest or first excited Landau levels. For the teragauss field strengths expected in neutron star magnetospheres, the relative rates for excited state transitions are found to be significant, especially for incident photon energies several times the cyclotron frequency. Since these transitions must result in the rapid emission of one or more cyclotron photons as well as the Compton-scattered photon, the scattering process actually becomes a photon 'splitting' mechanism which acts to soften hard photon spectra, and also provides a specific mechanism for populating higher Landau levels in the electron distribution function. The results should be significant for models of gamma-ray bursters and pulsating X-ray sources.

  17. Assembly of magnetic spheres in strong homogeneous magnetic field

    NASA Astrophysics Data System (ADS)

    Messina, René; Stanković, Igor

    2017-01-01

    The assembly in two dimensions of spherical magnets in strong magnetic field is addressed theoretically. It is shown that the attraction and assembly of parallel magnetic chains is the result of a delicate interplay of dipole-dipole interactions and short ranged excluded volume correlations. Minimal energy structures are obtained by numerical optimization procedure as well as analytical considerations. For a small number of constitutive magnets Ntot ≤ 26, a straight chain is found to be the ground state. In the regime of larger Ntot ≥ 27, the magnets form two touching chains with equally long tails at both ends. We succeed to identify the transition from two to three touching chains at Ntot = 129. Overall, this study sheds light on the mechanisms of the recently experimentally observed ribbon formation of superparamagnetic colloids via lateral aggregation of magnetic chains in magnetic field (Darras et al., 2016).

  18. Mechanics of magnetic fluid column in strong magnetic fields

    NASA Astrophysics Data System (ADS)

    Polunin, V. M.; Ryapolov, P. A.; Platonov, V. B.

    2017-06-01

    Elastic-and magnetic properties of magnetic fluid confined by ponderomotive force in a tube fixed in horizontal position are considered. The system is placed in a strong magnetic field under the influence of external static and dynamic perturbations. An experimental setup has been developed. A theoretical basis of the processes of magnetic colloid elastic deformation has been proposed. The values of the static ponderomotive elasticity coefficient and the elasticity coefficient under dynamic action are experimentally determined. The calculations of the saturation magnetization for two magnetic fluid samples, carried out according to the equation containing the dynamic elasticity coefficient, are in good agreement with the experimental magnetization curve. The described method is of interest when studying magnetophoresis and aggregation of nanoparticles in magnetic colloids.

  19. Ultracold atoms in strong synthetic magnetic fields

    NASA Astrophysics Data System (ADS)

    Ketterle, Wolfgang

    2015-03-01

    The Harper Hofstadter Hamiltonian describes charged particles in the lowest band of a lattice at high magnetic fields. This Hamiltonian can be realized with ultracold atoms using laser assisted tunneling which imprints the same phase into the wavefunction of neutral atoms as a magnetic field dose for electrons. I will describe our observation of a bosonic superfluid in a magnetic field with half a flux quantum per lattice unit cell, and discuss new possibilities for implementing spin-orbit coupling. Work done in collaboration with C.J. Kennedy, G.A. Siviloglou, H. Miyake, W.C. Burton, and Woo Chang Chung.

  20. Oscillations of Magnetic Fluid Column in Strong Magnetic Field

    NASA Astrophysics Data System (ADS)

    Polunin, V. M.; Storozhenko, A. M.; Platonov, V. B.; Lobova, O. V.; Ryapolov, P. A.

    2017-01-01

    The paper considers the results of measuring the elastic parameters (ponderomotive elasticity coefficient, oscillation frequency, attenuation coefficient) of the oscillatory system with an inertial element that is a magnetic fluid column retained in a tube due to magnetic levitation in a strong magnetic field. Elasticity is provided by the ponderomotive force which affects the upper and lower thin layers of the fluid column. Measurement results of vibration parameters of the oscillatory system can be useful for the investigations of magnetophoresis and aggregation of nanoparticles in magnetic fluids.

  1. Strongly interacting phases of metallic wires in strong magnetic field

    NASA Astrophysics Data System (ADS)

    Bulmash, Daniel; Jian, Chao-Ming; Qi, Xiao-Liang

    2017-07-01

    We investigate theoretically an interacting metallic wire with a strong magnetic field directed along its length and show that it is a highly tunable one-dimensional system. By considering a suitable change in spatial geometry, we build an analogy between the problem in the zeroth Landau level with Landau level degeneracy N to one-dimensional fermions with an N -component pseudospin degree of freedom and S U (2 ) -symmetric interactions. This analogy allows us to establish the phase diagram as a function of the interactions for small N (and make conjectures for large N ) using renormalization group and bosonization techniques. We find pseudospin-charge separation with a gapless U (1 ) charge sector and several possible strong-coupling phases in the pseudospin sector. For odd N , we find a fluctuating pseudospin-singlet charge density wave phase and a fluctuating pseudospin-singlet superconducting phase which are topologically distinct. For even N >2 , similar phases exist, although they are not topologically distinct, and an additional novel pseudospin-gapless phase appears. We discuss experimental conditions for observing our proposals.

  2. Heavy meson spectroscopy under strong magnetic field

    NASA Astrophysics Data System (ADS)

    Yoshida, Tetsuya; Suzuki, Kei

    2016-10-01

    Spectra of the neutral heavy mesons, ηc(1 S ,2 S ), J /ψ , ψ (2 S ), ηb(1 S ,2 S ,3 S ), ϒ (1 S ,2 S ,3 S ) , D , D*, B , B*, Bs and Bs*, in a homogeneous magnetic field are analyzed by using a potential model with constituent quarks. To obtain anisotropic wave functions and the corresponding eigenvalues, the cylindrical Gaussian expansion method is applied, where the wave functions for transverse and longitudinal directions in the cylindrical coordinate are expanded by the Gaussian bases separately. Energy level structures in the wide range of magnetic fields are obtained and the deformation of the wave functions is shown, which reflects effects of the spin mixing, the Zeeman splitting and quark Landau levels. The contribution from the magnetic catalysis in heavy-light mesons is discussed as a change of the light constituent quark mass.

  3. Physics in Strong Magnetic Fields Near Neutron Stars.

    ERIC Educational Resources Information Center

    Harding, Alice K.

    1991-01-01

    Discussed are the behaviors of particles and energies in the magnetic fields of neutron stars. Different types of possible research using neutron stars as a laboratory for the study of strong magnetic fields are proposed. (CW)

  4. Physics in Strong Magnetic Fields Near Neutron Stars.

    ERIC Educational Resources Information Center

    Harding, Alice K.

    1991-01-01

    Discussed are the behaviors of particles and energies in the magnetic fields of neutron stars. Different types of possible research using neutron stars as a laboratory for the study of strong magnetic fields are proposed. (CW)

  5. Topology, Magnetic Field, and Strongly Interacting Matter

    DOE PAGES

    Kharzeev, Dmitri E.

    2015-06-05

    Gauge theories with compact symmetry groups possess topologically nontrivial configurations of gauge field. This characteristic has dramatic implications for the vacuum structure of quantum chromodynamics (QCD) and for the behavior of QCD plasma, as well as for condensed matter systems with chiral quasi-particles. Here, I review the current status of this problem with an emphasis both on the interplay between chirality and a background magnetic field and on the observable manifestations of topology in heavy-ion collisions, Dirac semimetals, neutron stars, and the early Universe.

  6. Meson spectrum in strong magnetic fields

    NASA Astrophysics Data System (ADS)

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

    2013-05-01

    We study the relativistic quark-antiquark system embedded in a magnetic field (MF). The Hamiltonian containing confinement, one gluon exchange, and spin-spin interaction is derived. We analytically follow the evolution of the lowest meson states as a function of MF strength. Calculating the one gluon exchange interaction energy ⟨VOGE⟩ and spin-spin contribution ⟨aSS⟩ we have observed that these corrections remain finite at large MF, preventing the vanishing of the total ρ meson mass at some Bcrit, as previously thought. We display the ρ masses as functions of the MF in comparison with recent lattice data.

  7. Quark matter under strong magnetic fields in chiral models

    SciTech Connect

    Rabhi, Aziz; Providencia, Constanca

    2011-05-15

    The chiral model is used to describe quark matter under strong magnetic fields and is compared to other models, the MIT bag model and the two-flavor Nambu-Jona-Lasinio model. The effect of vacuum corrections due to the magnetic field is discussed. It is shown that if the magnetic-field vacuum corrections are not taken into account explicitly, the parameters of the models should be fitted to low-density meson properties in the presence of the magnetic field.

  8. Quark stars with strong magnetic fields: considering different magnetic field geometries

    NASA Astrophysics Data System (ADS)

    Wei, Wei; Liu, Xi-Wei; Zheng, Xiao-Ping

    2017-09-01

    We calculate the mass-radius relationship of quark stars with the magnetized density-dependent quark mass model in this work, considering two magnetic field geometries: a statistically isotropic, tangled field and a force-free configuration. In both cases, magnetic field production decreases in the case of maximum quark star mass. Furthermore, a tangled, isotropic magnetic field has a relatively smaller impact on the mass and radius, compared to the force-free configuration, which implies that the geometry of the interior magnetic field is at least as important as the field strength itself when the influence of the strong magnetic field on the mass and radius is assessed.

  9. Warm and dense stellar matter under strong magnetic fields

    SciTech Connect

    Rabhi, A.; Panda, P. K.; Providencia, C.

    2011-09-15

    We investigate the effects of strong magnetic fields on the equation of state of warm stellar matter as it may occur in a protoneutron star. Both neutrino-free and neutrino-trapped matter at a fixed entropy per baryon are analyzed. A relativistic mean-field nuclear model, including the possibility of hyperon formation, is considered. A density-dependent magnetic field with a magnitude of 10{sup 15} G at the surface and not more than 3x10{sup 18} G at the center is considered. The magnetic field gives rise to a neutrino suppression, mainly at low densities, in matter with trapped neutrinos. It is shown that a hybrid protoneutron star will not evolve into a low-mass black hole if the magnetic field is strong enough and the magnetic field does not decay. However, the decay of the magnetic field after cooling may give rise to the formation of a low-mass black hole.

  10. Operating a magnetic nozzle helicon thruster with strong magnetic field

    SciTech Connect

    Takahashi, Kazunori Komuro, Atsushi; Ando, Akira

    2016-03-15

    A pulsed axial magnetic field up to ∼2.8 kG is applied to a 26-mm-inner-diameter helicon plasma thruster immersed in a vacuum chamber, and the thrust is measured using a pendulum target. The pendulum is located 30-cm-downstream of the thruster, and the thruster rf power and argon flow rate are fixed at 1 kW and 70 sccm (which gives a chamber pressure of 0.7 mTorr). The imparted thrust increases as the applied magnetic field is increased and saturates at a maximum value of ∼9.5 mN for magnetic field above ∼2 kG. At the maximum magnetic field, it is demonstrated that the normalized plasma density, and the ion flow energy in the magnetic nozzle, agree within ∼50% and of 10%, respectively, with a one-dimensional model that ignores radial losses from the nozzle. This magnetic nozzle model is combined with a simple global model of the thruster source that incorporates an artificially controlled factor α, to account for radial plasma losses to the walls, where α = 0 and 1 correspond to zero losses and no magnetic field, respectively. Comparison between the experiments and the model implies that the radial losses in the thruster source are experimentally reduced by the applied magnetic field to about 10% of that obtained from the no magnetic field model.

  11. Pion Production from Proton Synchrotron Radiation in Strong Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Maruyama, Tomoyuki; Cheoun, Myung-Ki; Kajino, Toshitaka; Mathews, Grant J.

    We study pion production by proton synchrotron radiation in the presence of a strong magnetic field. In this study we find that the decay width satisfies a robust scaling relation. This scaling implies that one can infer the decay width in more realistic magnetic fields of 1015 G, where ni,f ˜ 1012-1013, from the results for ni,f ˜ 104-105. Then, we present the resultant pion intensity and angular distributions for realistic magnetic field strengths.

  12. Thermoelectric effects in organic conductors in a strong magnetic field

    SciTech Connect

    Kirichenko, O. V.; Peschanskii, V. G. Hasan, R. A.

    2007-07-15

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

  13. Physics in strong magnetic fields near neutron stars

    NASA Technical Reports Server (NTRS)

    Harding, Alice K.

    1991-01-01

    Electromagnetic phenomena occurring in the strong magnetic fields of neutron stars are currently of great interest in high-energy astrophysics. Observations of rotation rate changes and cyclotron lines in pulsars and gamma-ray bursts indicate that surface magnetic fields of neutron stars often exceed a trillion gauss. In fields this strong, where electrons behave much as if they were in bound atomic states, familiar processes undergo profound changes, and exotic processes become important. Strong magnetic fields affect the physics in several fundamental ways: energies perpendicular to the field are quantized, transverse momentum is not conserved, and electron-positron spin is important. Neutron stars therefore provide a unique laboratory for the study of physics in extremely high fields that cannot be generated on earth.

  14. Observability of atomic line features in strong magnetic fields

    NASA Technical Reports Server (NTRS)

    Wunner, G.; Ruder, H.; Herold, H.; Truemper, J.

    1981-01-01

    The physical properties of atoms in superstrong magnetic fields, characteristic of neutron stars, and the possibility of detecting magnetically strongly shifted atomic lines in the spectra of magnetized X-ray pulsars are discussed. It is suggested that it is recommendable to look for magnetically strongly shifted Fe 26 Lyman lines in rotating neutron stars of not too high luminosity using spectrometers working in the energy range 10 - 20 keV, with sensitivities to minus 4 power photons per sq cm and second, and resolution E/delta E approx. 10-100.

  15. Nerve excitation and recovery processes under strong static magnetic fields

    NASA Astrophysics Data System (ADS)

    Eguchi, Yawara; Ueno, Shoogo; Tatsuoka, Hozumi

    2003-05-01

    The membrane excitation and refractory processes of nerve fibers exposed to strong static magnetic fields of 8 T were studied. Sciatic nerve bundles of frogs were electrically excited by a pair of pulses with varying interpulse intervals, and the compound action potentials were measured under magnetic field exposures. Our experimental results show that the conduction velocity was not affected by 8 T magnetic fields; however, the membrane excitation during the recovery process in the relative refractory period was enhanced by 10% of maximal peak of nerve excitation by magnetic field exposure for 3 h. In this study, the optimal time interval for increased membrane excitation during the recovery process was between 1.0 and 1.1 ms. In other words, membrane excitation during the recovery process in the relative refractory period was affected by the magnetic fields just after Na+ channels were inactivated.

  16. Hydrogen molecule in a strong parallel magnetic field

    NASA Astrophysics Data System (ADS)

    Kravchenko, Yu. P.; Liberman, M. A.

    1998-05-01

    We investigate the hydrogen molecule in a strong parallel magnetic field using a fully numerical Hartree-Fock approach. We find that for magnetic fields below 4.2×104 T the ground state of H2 is the strongly bound singlet state 1Σg, for magnetic fields stronger than 3×106 T the ground state of the molecule is the strongly bound triplet 3Πu, and for magnetic fields between 4.2×104 T and 3×106 T the symmetry of the ground state is the triplet state 3Σu, which is characterized by repulsion at intermediate internuclear distances and by a weak quadrupole-quadrupole interaction between atoms at large internuclear separation. In this region of magnetic field strength the hydrogen molecule is bound weakly, if at all; the hydrogen atoms behave like a weakly nonideal gas of Bose particles and can form a superfluid phase predicted in earlier works [Korolev and Liberman, Phys. Rev. Lett. 72, 270 (1994)]. For magnetic fields between ~3×105 T and 3×106 T the triplet state 3Πu is found to be metastable. This state may be responsible for an unknown excitonic line observed experimentally [Timofeev and Chernenko, JETP Lett. 61, 617 (1995)].

  17. Momentum transport in strongly coupled anisotropic plasmas in the presence of strong magnetic fields

    NASA Astrophysics Data System (ADS)

    Finazzo, Stefano Ivo; Critelli, Renato; Rougemont, Romulo; Noronha, Jorge

    2016-09-01

    We present a holographic perspective on momentum transport in strongly coupled, anisotropic non-Abelian plasmas in the presence of strong magnetic fields. We compute the anisotropic heavy quark drag forces and Langevin diffusion coefficients and also the anisotropic shear viscosities for two different holographic models, namely, a top-down deformation of strongly coupled N =4 super-Yang-Mills theory triggered by an external Abelian magnetic field, and a bottom-up Einstein-Maxwell-dilaton (EMD) model which is able to provide a quantitative description of lattice QCD thermodynamics with (2 +1 ) flavors at both zero and nonzero magnetic fields. We find that, in general, energy loss and momentum diffusion through strongly coupled anisotropic plasmas are enhanced by a magnetic field being larger in transverse directions than in the direction parallel to the magnetic field. Moreover, the anisotropic shear viscosity coefficient is smaller in the direction of the magnetic field than in the plane perpendicular to the field, which indicates that strongly coupled anisotropic plasmas become closer to the perfect fluid limit along the magnetic field. We also present, in the context of the EMD model, holographic predictions for the entropy density and the crossover critical temperature in a wider region of the (T , B ) phase diagram that has not yet been covered by lattice simulations. Our results for the transport coefficients in the phenomenologically realistic magnetic EMD model could be readily used as inputs in numerical codes for magnetohydrodynamics.

  18. Vacuum in a strong magnetic field as a hyperbolic metamaterial.

    PubMed

    Smolyaninov, Igor I

    2011-12-16

    As demonstrated by Chernodub, vacuum in a strong magnetic field behaves as Abrikosov vortex lattice in a type-II superconductor. We investigate electromagnetic behavior of vacuum in this state and demonstrate that vacuum behaves as a hyperbolic metamaterial. If the magnetic field is constant, low frequency extraordinary photons experience this medium as a (3+1) Minkowski spacetime in which the role of time is played by the spatial z coordinate. Variations of the magnetic field curve this spacetime, and may lead to formation of "electromagnetic black holes." Since hyperbolic metamaterials behave as diffractionless "perfect lenses," and large enough magnetic fields probably existed in the early Universe, the demonstrated hyperbolic behavior of early vacuum may have imprints in the large scale structure of the present-day Universe. © 2011 American Physical Society

  19. Vacuum in a Strong Magnetic Field as a Hyperbolic Metamaterial

    SciTech Connect

    Smolyaninov, Igor I.

    2011-12-16

    As demonstrated by Chernodub, vacuum in a strong magnetic field behaves as Abrikosov vortex lattice in a type-II superconductor. We investigate electromagnetic behavior of vacuum in this state and demonstrate that vacuum behaves as a hyperbolic metamaterial. If the magnetic field is constant, low frequency extraordinary photons experience this medium as a (3+1) Minkowski spacetime in which the role of time is played by the spatial z coordinate. Variations of the magnetic field curve this spacetime, and may lead to formation of ''electromagnetic black holes''. Since hyperbolic metamaterials behave as diffractionless ''perfect lenses'', and large enough magnetic fields probably existed in the early Universe, the demonstrated hyperbolic behavior of early vacuum may have imprints in the large scale structure of the present-day Universe.

  20. Molecules and chains in a strong magnetic field - Statistical treatment

    NASA Technical Reports Server (NTRS)

    Abrahams, Andrew M.; Shapiro, Stuart L.

    1991-01-01

    A Thomas-Fermi-Dirac-Weizsaecker statistical model is developed and employed to investigate diatomic molecules and infinite molecular chains in strong magnetic fields. The standard magnetic Thomas-Fermi-Dirac kinetic, potential, and exchange energy functionals are supplemented by a gradient correction to the kinetic energy. The numerical method used for solving this system in two spatial dimensions is detailed. Numerical solutions for a wide range of magnetic strengths and elements are presented to demonstrate the robustness, as well as the limitations, of the statistical approach. These calculations qualitatively reproduce many of the results of detailed quantum mechanical treatments. For example, the fractional binding energy is greatest for low atomic numbers and for strong magnetic fields.

  1. Anisotropic magnetohydrodynamic turbulence in a strong external magnetic field

    NASA Technical Reports Server (NTRS)

    Montgomery, D.; Turner, L.

    1981-01-01

    A strong external dc magnetic field introduces a basic anisotropy in incompressible MHD turbulence. The modifications that this is likely to produce in the properties of the turbulence are investigated for high Reynolds numbers. It is found that the turbulent spectrum splits into two parts: (1) an essentially two-dimensional spectrum with both the velocity field and the magnetic fluctuations perpendicular to the dc magnetic field, and (2) a generally weaker and more nearly isotropic spectrum of Alfven waves. These results are discussed in relation to measurements from the Culham-Harwell Zeta pinch device and the UCLA Macrorotor tokamak, as well as in relation to measurements of MHD turbulence in the solar wind.

  2. Anisotropic magnetohydrodynamic turbulence in a strong external magnetic field

    NASA Technical Reports Server (NTRS)

    Montgomery, D.; Turner, L.

    1981-01-01

    A strong external dc magnetic field introduces a basic anisotropy into incompressible magnetohydrodynamic turbulence. The modifications that this is likely to produce in the properties of the turbulence are explored for the high Reynolds number case. The conclusion is reached that the turbulent spectrum splits into two parts: an essentially two dimensional spectrum with both the velocity field and magnetic fluctuations perpendicular to the dc magnetic field, and a generally weaker and more nearly isotropic spectrum of Alfven waves. A minimal characterization of the spectral density tensors is given. Similarities to measurements from the Culham-Harwell Zeta pinch device and the UCLA Macrotor Tokamak are remarked upon, as are certain implications for the Belcher and Davis measurements of magnetohydrodynamic turbulence in the solar wind.

  3. Plasma Rotation Control Experiment in a Strongly Diverging Magnetic Field

    NASA Astrophysics Data System (ADS)

    Terasaka, Kenichiro; Furuta, Kanshi; Yoshimura, Shinji; Aramaki, Mitsutoshi; Tanaka, Masayoshi Y.

    2016-10-01

    It has been recognized that the plasma rotation affects the plasma flow structure along the magnetic field line. However, the effect of plasma rotation on structure formation in a strongly diverging magnetic field with magnetized electrons and unmagnetized ions has not been fully understood, so far. Understanding the flow structure formation in an ion-unmagnetized plasma is essential to control ion streamline detachment from the magnetic field line and also necessary to study the astrophysical phenomena in laboratory. In order to clarify the effect of plasma rotation in a diverging magnetic field, we have performed the plasma rotation control experiment in the HYPER-II device at Kyushu Univ., Japan. A set of cylindrical electrode was utilized to control the radial electric field, and the profile of azimuthal E × B rotation has been changed. We present the experimental results on the electron density pileup and the flow reversal appeared in the rotating plasma. This study was supported by JSPS KAKENHI Grant Number 16K05633.

  4. Strong parallel magnetic field effects on the hydrogen molecular ion

    NASA Astrophysics Data System (ADS)

    Guan, Xiaoxu; Li, Baiwen; Taylor, K. T.

    2003-09-01

    Equilibrium distances, binding energies and dissociation energies for the ground and low-lying states of the hydrogen molecular ion in a strong magnetic field parallel to the internuclear axis are calculated and refined, by using the two-dimensional pseudospectral method. High-precision results are presented for the binding energies over a wider field regime than already given in the literature (Kravchenko and Liberman 1997 Phys. Rev. A 55 2701). The present work removes a long-standing discrepancy for the Req value in the 1sigmau state at a field strength of 1.0 × 106 T. The dissociation energies of the antibonding 1pig state induced by magnetic fields are determined accurately. We have also observed that the antibonding 1pig potential energy curve develops a minimum if the field is sufficiently strong. Some unreliable results in the literature are pointed out and discussed. A way to efficiently treat vibrational processes and coupling between the nuclear and the electronic motions in magnetic fields is also suggested within a three-dimensional pseudospectral scheme.

  5. RF breakdown of 805 MHz cavities in strong magnetic fields

    SciTech Connect

    Bowring, D.; Stratakis, D.; Kochemirovskiy, A.; Leonova, M.; Moretti, A.; Palmer, M.; Peterson, D.; Yonehara, K.; Freemire, B.; Lane, P.; Torun, Y.; Haase, A.

    2015-05-03

    Ionization cooling of intense muon beams requires the operation of high-gradient, normal-conducting RF structures in the presence of strong magnetic fields. We have measured the breakdown rate in several RF cavities operating at several frequencies. Cavities operating within solenoidal magnetic fields B > 0.25 T show an increased RF breakdown rate at lower gradients compared with similar operation when B = 0 T. Ultimately, this breakdown behavior limits the maximum safe operating gradient of the cavity. Beyond ionization cooling, this issue affects the design of photoinjectors and klystrons, among other applications. We have built an 805 MHz pillbox-type RF cavity to serve as an experimental testbed for this phenomenon. This cavity is designed to study the problem of RF breakdown in strong magnetic fields using various cavity materials and surface treatments, and with precise control over sources of systematic error. We present results from tests in which the cavity was run with all copper surfaces in a variety of magnetic fields.

  6. Saturated symmetric nuclear matter in strong magnetic fields

    NASA Astrophysics Data System (ADS)

    Diener, J. P. W.; Scholtz, F. G.

    2013-06-01

    Strongly magnetized symmetric nuclear matter is investigated within the context of effective baryon-meson exchange models. The magnetic field is coupled to the charge as well as the dipole moment of the baryons by including the appropriate terms in the Lagrangian density. The saturation density of magnetized, symmetric nuclear matter ρ0(B) was calculated for magnetic fields of the order of 1017 gauss. For the calculated range of ρ0(B) the binding energy, symmetry energy coefficient a4, and compressibility K of nuclear matter were also calculated. It is found that with an increasing magnetic field ρ0(B) increases, while the system becomes less bound. Furthermore, the depopulation of proton Landau levels leaves a distinct fluctuating imprint on K and a4. The calculations were also performed for increased values of the baryon magnetic dipole moment. By increasing the dipole moment strength ρ0(B) is found to decrease, but the system becomes more tightly bound while the fluctuations in K and a4 persist.

  7. Localized electron heating by strong guide-field magnetic reconnection

    NASA Astrophysics Data System (ADS)

    Guo, Xuehan; Inomoto, Michiaki; Sugawara, Takumichi; Yamasaki, Kotaro; Ushiki, Tomohiko; Ono, Yasushi

    2015-10-01

    Localized electron heating of magnetic reconnection was studied under strong guide-field using two merging spherical tokamak plasmas in the University of Tokyo Spherical Tokamak experiment. Our new slide-type two-dimensional Thomson scattering system is documented for the first time the electron heating localized around the X-point. Shape of the high electron temperature area does not agree with that of energy dissipation term Et.jt . If we include a guide-field effect term Bt/(Bp+αBt) for Et.jt , the energy dissipation area becomes localized around the X-point, suggesting that the electrons are accelerated by the reconnection electric field parallel to the magnetic field and thermalized around the X-point.

  8. Strongly interacting photons in a synthetic magnetic field

    NASA Astrophysics Data System (ADS)

    Roushan, Pedram; Neill, C.; Megrant, A.; Chen, Y.; Barends, R.; Cambell, B.; Chen, Z.; Chiaro, B.; Dunsworth, A.; Fowler, A.; Jeffrey, E.; Kelly, J.; Lucero, E.; Mutus, J.; O'Malley, P.; Neeley, M.; Quintana, C.; Sank, D.; Vainsencher, A.; Wenner, J.; White, T.; Kapit, E.; Martinis, J.

    Interacting electrons in the presence of magnetic fields exhibit some of the most fascinating phases in condensed matter systems. Realizing these phases in an engineered platform could provide deeper insight into their. Using three superconducting qubits, we synthesize artificial magnetic fields by modulating the inter-qubit coupling. In the closed loop formed by the qubits, we observe the directional circulation of a microwave photon as well as chiral groundstate currents, the signatures of broken time-reversal symmetry. The existence of strong interactions in our system is seen via the creation of photon vacancies, or ''holes'', which circulate in the opposite direction from the photons. Our work demonstrates an experimental approach for engineering quantum phases of strongly interacting bosons.

  9. Continuous spectra of atomic hydrogen in a strong magnetic field

    NASA Astrophysics Data System (ADS)

    Zhao, L. B.; Zatsarinny, O.; Bartschat, K.

    2016-09-01

    We describe a theoretical method, developed in the coupled-channel formalism, to study photoionization of H atoms in a strong magnetic field of a size that is typical for magnetic white dwarfs. The coupled Schrödinger equations are solved numerically using the renormalized Numerov method proposed by Johnson [B. R. Johnson, J. Chem. Phys. 67, 4086 (1977), 10.1063/1.435384; B. R. Johnson, J. Chem. Phys. 69, 4678 (1978), 10.1063/1.436421]. The distinct advantage of this method is the fact that no overflow problems are encountered in the classically forbidden region, and hence the method exhibits excellent numerical stability. Photoionization cross sections are presented for magnetized H atoms in the ground and 2 p excited states. The calculated results are compared with those obtained by other theories. The present method is particularly useful for explaining the complex features of continuous spectra in a strong magnetic field and hence provides an efficient tool for modeling photoionization spectra observed in the atmosphere of magnetic white dwarfs.

  10. Hig Resolution Seismometer Insensitive to Extremely Strong Magnetic Fields

    SciTech Connect

    Abramovich, Igor A

    2009-07-14

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

  11. Colliding-wind Binaries with Strong Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Kissmann, R.; Reitberger, K.; Reimer, O.; Reimer, A.; Grimaldo, E.

    2016-12-01

    The dynamics of colliding-wind binary (CWB) systems and conditions for efficient particle acceleration therein have attracted multiple numerical studies in recent years. These numerical models seek an explanation of the thermal and nonthermal emission of these systems as seen by observations. In the nonthermal regime, radio and X-ray emission is observed for several of these CWBs, while gamma-ray emission has so far only been found in η Carinae and possibly in WR 11. Energetic electrons are deemed responsible for a large fraction of the observed high-energy photons in these systems. Only in the gamma-ray regime might there be, depending on the properties of the stars, a significant contribution of emission from neutral pion decay. Thus, studying the emission from CWBs requires detailed models of the acceleration and propagation of energetic electrons. This in turn requires a detailed understanding of the magnetic field, which will affect not only the energy losses of the electrons but also, in the case of synchrotron emission, the directional dependence of the emissivity. In this study we investigate magnetohydrodynamic simulations of different CWB systems with magnetic fields that are strong enough to have a significant effect on the winds. Such strong fields require a detailed treatment of the near-star wind acceleration zone. We show the implementation of such simulations and discuss results that demonstrate the effect of the magnetic field on the structure of the wind collision region.

  12. Pair annihilation into neutrinos in strong magnetic fields.

    NASA Technical Reports Server (NTRS)

    Canuto, V.; Fassio-Canuto, L.

    1973-01-01

    Among the processes that are of primary importance for the thermal history of a neutron star is electron-positron annihilation into neutrinos and photoneutrinos. These processes are computed in the presence of a strong magnetic field typical of neutron stars, and the results are compared with the zero-field case. It is shown that the neutrino luminosity Q(H) is greater than Q(O) for temperatures up to T about equal to 3 x 10 to the 8th power K and densities up to 1,000,000 g/cu cm.

  13. Pair annihilation into neutrinos in strong magnetic fields.

    NASA Technical Reports Server (NTRS)

    Canuto, V.; Fassio-Canuto, L.

    1973-01-01

    Among the processes that are of primary importance for the thermal history of a neutron star is electron-positron annihilation into neutrinos and photoneutrinos. These processes are computed in the presence of a strong magnetic field typical of neutron stars, and the results are compared with the zero-field case. It is shown that the neutrino luminosity Q(H) is greater than Q(O) for temperatures up to T about equal to 3 x 10 to the 8th power K and densities up to 1,000,000 g/cu cm.

  14. Using Strong Magnetic Fields to Control Solutal Convection

    NASA Technical Reports Server (NTRS)

    Ramachandran, N.; Leslie, F. W.

    2003-01-01

    An important component in biotechnology, particularly in the area of protein engineering and rational drug design is the knowledge of the precise three-dimensional molecular structure of proteins. The quality of structural information obtained from X-ray diffraction methods is directly dependent on the degree of perfection of the protein crystals. As a consequence, the growth of high quality macromolecular crystals for diffraction analyses has been the central focus for biochemists, biologists, and bioengineers. Macromolecular crystals are obtained from solutions that contain the crystallizing species in equilibrium with higher aggregates, ions, precipitants, other possible phases of the protein, foreign particles, the walls of the container, and a likely host of other impurities. By changing transport modes in general, i.e., reduction of convection and sedimentation, as is achieved in microgravity , we have been able to dramatically affect the movement and distribution of macromolecules in the fluid, and thus their transport, formation of crystal nuclei, and adsorption to the crystal surface. While a limited number of high quality crystals from space flights have been obtained, as the recent National Research Council (NRC) review of the NASA microgravity crystallization program pointed out, the scientific approach and research in crystallization of proteins has been mainly empirical yielding inconclusive results. We postulate that we can reduce convection in ground-based experiments and we can understand the different aspects of convection control through the use of strong magnetic fields and field gradients. We postulate that limited convection in a magnetic field will provide the environment for the growth of high quality crystals. The approach exploits the variation of fluid magnetic susceptibility with concentration for this purpose and the convective damping is realized by appropriately positioning the crystal growth cell so that the magnetic susceptibility

  15. Using Strong Magnetic Fields to Control Solutal Convection

    NASA Technical Reports Server (NTRS)

    Ramachandran, N.; Leslie, F. W.

    2003-01-01

    An important component in biotechnology, particularly in the area of protein engineering and rational drug design is the knowledge of the precise three-dimensional molecular structure of proteins. The quality of structural information obtained from X-ray diffraction methods is directly dependent on the degree of perfection of the protein crystals. As a consequence, the growth of high quality macromolecular crystals for diffraction analyses has been the central focus for biochemists, biologists, and bioengineers. Macromolecular crystals are obtained from solutions that contain the crystallizing species in equilibrium with higher aggregates, ions, precipitants, other possible phases of the protein, foreign particles, the walls of the container, and a likely host of other impurities. By changing transport modes in general, i.e., reduction of convection and sedimentation, as is achieved in microgravity , we have been able to dramatically affect the movement and distribution of macromolecules in the fluid, and thus their transport, formation of crystal nuclei, and adsorption to the crystal surface. While a limited number of high quality crystals from space flights have been obtained, as the recent National Research Council (NRC) review of the NASA microgravity crystallization program pointed out, the scientific approach and research in crystallization of proteins has been mainly empirical yielding inconclusive results. We postulate that we can reduce convection in ground-based experiments and we can understand the different aspects of convection control through the use of strong magnetic fields and field gradients. We postulate that limited convection in a magnetic field will provide the environment for the growth of high quality crystals. The approach exploits the variation of fluid magnetic susceptibility with concentration for this purpose and the convective damping is realized by appropriately positioning the crystal growth cell so that the magnetic susceptibility

  16. Strong magnetic fields in normal galaxies at high redshift.

    PubMed

    Bernet, Martin L; Miniati, Francesco; Lilly, Simon J; Kronberg, Philipp P; Dessauges-Zavadsky, Miroslava

    2008-07-17

    The origin and growth of magnetic fields in galaxies is still something of an enigma. It is generally assumed that seed fields are amplified over time through the dynamo effect, but there are few constraints on the timescale. It was recently demonstrated that field strengths as traced by rotation measures of distant (and hence ancient) quasars are comparable to those seen today, but it was unclear whether the high fields were in the unusual environments of the quasars themselves or distributed along the lines of sight. Here we report high-resolution spectra that demonstrate that the quasars with strong Mg II absorption lines are unambiguously associated with larger rotation measures. Because Mg ii absorption occurs in the haloes of normal galaxies along the sightlines to the quasars, this association requires that organized fields of surprisingly high strengths are associated with normal galaxies when the Universe was only about one-third of its present age.

  17. Diffusion of fast rising strong magnetic fields into conductors

    NASA Astrophysics Data System (ADS)

    Labetskaya, N. A.; Oreshkin, V. I.; Chaikovsky, S. A.; Datsko, I. M.; Kuskova, N. I.; Rud, A. D.

    2014-11-01

    The basic processes occurring in a conductor exploding in a current skinning mode are the propagation of a nonlinear magnetic diffusion wave in the conductor and the formation of low-temperature plasma at its surface. An experimental study of the phenomenon of nonlinear magnetic diffusion into conductors in magnetic fields of induction rising at a rate up to 3·109 T/s was carried out on the MIG generator capable of producing a peak current up to 2.5 MA within a rise time of 100 ns. It has been found experimentally that the average velocity of a nonlinear magnetic diffusion wave in an aluminum conductor placed in a strong magnetic field (up to 300 T) rising at a high rate (on average, 3·109 T/s) is (2.7÷3.3)·105 cm/s. This is comparable to the velocity of sound in aluminum under normal conditions and reasonably agrees with predictions of numerical simulations.

  18. Localized Electron Heating by Strong Guide-Field Magnetic Reconnection

    NASA Astrophysics Data System (ADS)

    Guo, Xuehan; Sugawara, Takumichi; Inomoto, Michiaki; Yamasaki, Kotaro; Ono, Yasushi; UTST Team

    2015-11-01

    Localized electron heating of magnetic reconnection was studied under strong guide-field (typically Bt 15Bp) using two merging spherical tokamak plasmas in Univ. Tokyo Spherical Tokamak (UTST) experiment. Our new slide-type two-dimensional Thomson scattering system documented for the first time the electron heating localized around the X-point. The region of high electron temperature, which is perpendicular to the magnetic field, was found to have a round shape with radius of 2 [cm]. Also, it was localized around the X-point and does not agree with that of energy dissipation term Et .jt . When we include a guide-field effect term Bt / (Bp + αBt) for Et .jt where α =√{ (vin2 +vout2) /v∥2 } , the energy dissipation area becomes localized around the X-point, suggesting that the electrons are accelerated by the reconnection electric field parallel to the magnetic field and thermalized around the X-point. This work was supported by JSPS A3 Foresight Program ``Innovative Tokamak Plasma Startup and Current Drive in Spherical Torus,'' a Grant-in-Aid from the Japan Society for the Promotion of Science (JSPS) Fellows 15J03758.

  19. Mesons in strong magnetic fields: (I) General analyses

    DOE PAGES

    Hattori, Koichi; Kojo, Toru; Su, Nan

    2016-03-21

    Here, we study properties of neutral and charged mesons in strong magnetic fields |eB| >> Λ2QCD with ΛQCD being the QCD renormalization scale. Assuming long-range interactions, we examine magnetic-field dependences of various quantities such as the constituent quark mass, chiral condensate, meson spectra, and meson wavefunctions by analyzing the Schwinger–Dyson and Bethe–Salpeter equations. Based on the density of states obtained from these analyses, we extend the hadron resonance gas (HRG) model to investigate thermodynamics at large B. As B increases the meson energy behaves as a slowly growing function of the meson's transverse momenta, and thus a large number ofmore » meson states is accommodated in the low energy domain; the density of states at low temperature is proportional to B2. This extended transverse phase space in the infrared regime significantly enhances the HRG pressure at finite temperature, so that the system reaches the percolation or chiral restoration regime at lower temperature compared to the case without a magnetic field; this simple picture would offer a gauge invariant and intuitive explanation of the inverse magnetic catalysis.« less

  20. Mesons in strong magnetic fields: (I) General analyses

    NASA Astrophysics Data System (ADS)

    Hattori, Koichi; Kojo, Toru; Su, Nan

    2016-07-01

    We study properties of neutral and charged mesons in strong magnetic fields | eB | ≫ΛQCD2 with ΛQCD being the QCD renormalization scale. Assuming long-range interactions, we examine magnetic-field dependences of various quantities such as the constituent quark mass, chiral condensate, meson spectra, and meson wavefunctions by analyzing the Schwinger-Dyson and Bethe-Salpeter equations. Based on the density of states obtained from these analyses, we extend the hadron resonance gas (HRG) model to investigate thermodynamics at large B. As B increases the meson energy behaves as a slowly growing function of the meson's transverse momenta, and thus a large number of meson states is accommodated in the low energy domain; the density of states at low temperature is proportional to B2. This extended transverse phase space in the infrared regime significantly enhances the HRG pressure at finite temperature, so that the system reaches the percolation or chiral restoration regime at lower temperature compared to the case without a magnetic field; this simple picture would offer a gauge invariant and intuitive explanation of the inverse magnetic catalysis.

  1. Mesons in strong magnetic fields: (I) General analyses

    SciTech Connect

    Hattori, Koichi; Kojo, Toru; Su, Nan

    2016-03-21

    Here, we study properties of neutral and charged mesons in strong magnetic fields |eB| >> Λ2QCD with ΛQCD being the QCD renormalization scale. Assuming long-range interactions, we examine magnetic-field dependences of various quantities such as the constituent quark mass, chiral condensate, meson spectra, and meson wavefunctions by analyzing the Schwinger–Dyson and Bethe–Salpeter equations. Based on the density of states obtained from these analyses, we extend the hadron resonance gas (HRG) model to investigate thermodynamics at large B. As B increases the meson energy behaves as a slowly growing function of the meson's transverse momenta, and thus a large number of meson states is accommodated in the low energy domain; the density of states at low temperature is proportional to B2. This extended transverse phase space in the infrared regime significantly enhances the HRG pressure at finite temperature, so that the system reaches the percolation or chiral restoration regime at lower temperature compared to the case without a magnetic field; this simple picture would offer a gauge invariant and intuitive explanation of the inverse magnetic catalysis.

  2. Helium atoms and molecules in strong magnetic fields

    NASA Astrophysics Data System (ADS)

    Mori, K.

    Recent theoretical studies have shown that the neutron star surface may be composed of helium or heavier elements as hydrogen may be quickly depleted by diffuse nuclear burning Chang Bildsten However while Hydrogen atmospheres have been studied in great details atomic data for helium is available only for He ion Pavlov Bezchastnov 2005 We performed Hartree-Fock type calculation for Helium atom and molecules and computed their binding ionization and dissociation energies in strong magnetic fields B sim10 12 -- 10 15 G We will present ionization balance of Helium atmospheres at typical magnetic field strengths and temperatures to radio-quiet neutron stars and AXPs We will also discuss several implications of helium atmosphere to X-ray data of isolated neutron stars focusing on the detected spectral features

  3. Dynamic Elasticity of a Magnetic Fluid Column in a Strong Magnetic Field

    NASA Astrophysics Data System (ADS)

    Polunin, V. M.; Ryapolov, P. A.; Shel'deshova, E. V.; Kuz'ko, A. E.; Aref'ev, I. M.

    2017-07-01

    The elastomagnetic parameters of a magnetic fluid kept by magnetic levitation in a tube placed horizontally in a strong magnetic field are measured, including the oscillation frequency, the ponderomotive and dynamic elasticity coefficients, the magnetization curve, and the magnetic field strength and its gradient. Results of calculations for the model of ponderomotive elasticity for the examined sample of the magnetic fluid corrected for the resistance of the moving viscous fluid are in good agreement with the experimental magnetization curve. The described method is of interest for a study of magnetophoresis, nanoparticle aggregations, viscosity, and their time dependences in magnetic colloids.

  4. Strong magnetic fields, galaxy formation, and the Galactic engine

    NASA Technical Reports Server (NTRS)

    Greyber, Howard D.

    1989-01-01

    The strong-magnetic-field model proposed as an energy source for AGN and quasars by Greyber (1961, 1962, 1964, 1967, 1984, 1988, and 1989) is discussed. The basic principles of the model are reviewed; its advantages (in explaining the observed features of AGN and quasars) over models based on a rotating accretion disk are indicated in a table; and its implications for galaxy and quasar formation are explored. The gravitationally bound current loops detected in nearby spiral galaxies are interpreted as weak remnants of the current loops present during their formation. An observational search for a similar loop near the Galactic center is proposed.

  5. Observations of Strong Magnetic Fields in Nondegenerate Stars

    NASA Astrophysics Data System (ADS)

    Linsky, Jeffrey L.; Schöller, Markus

    2015-10-01

    We review magnetic-field measurements of nondegenerate stars across the Hertzprung-Russell diagram for main sequence, premain sequence, and postmain sequence stars. For stars with complex magnetic-field morphologies, which includes all G-M main sequence stars, the analysis of spectra obtained in polarized vs unpolarized light provides very different magnetic measurements because of the presence or absence of cancellation by oppositely directed magnetic fields within the instrument's spatial resolution. This cancellation can be severe, as indicated by the spatially averaged magnetic field of the Sun viewed as a star. These averaged fields are smaller by a factor of 1000 or more compared to spatially resolved magnetic-field strengths. We explain magnetic-field terms that characterize the fields obtained with different measurement techniques. Magnetic fields typically control the structure of stellar atmospheres in and above the photosphere, the heating rates of stellar chromospheres and coronae, mass and angular momentum loss through stellar winds, chemical peculiarity, and the emission of high energy photons, which is critically important for the evolution of protoplanetary disks and the habitability of exoplanets. Since these effects are governed by the star's magnetic energy, which is proportional to the magnetic-field strength squared and its fractional surface coverage, it is important to measure or reliably infer the true magnetic-field strength and filling factor across a stellar disk. We summarize magnetic-field measurements obtained with the different observing techniques for different types of stars and estimate the highest magnetic-field strengths. We also comment on the different field morphologies observed for stars across the H-R diagram, typically inferred from Zeeman-Doppler imaging and rotational modulation observations,

  6. Anomalous electrodynamics of neutral pion matter in strong magnetic fields

    NASA Astrophysics Data System (ADS)

    Brauner, Tomáš; Kadam, Saurabh V.

    2017-03-01

    The ground state of quantum chromodynamics in sufficiently strong external magnetic fields and at moderate baryon chemical potential is a chiral soliton lattice (CSL) of neutral pions [1]. We investigate the interplay between the CSL structure and dynamical electromagnetic fields. Our main result is that in presence of the CSL background, the two physical photon polarizations and the neutral pion mix, giving rise to two gapped excitations and one gapless mode with a nonrelativistic dispersion relation. The nature of this mode depends on the direction of its propagation, interpolating between a circularly polarized electromagnetic wave [2] and a neutral pion surface wave, which in turn arises from the spontaneously broken translation invariance. Quite remarkably, there is a neutral-pion-like mode that remains gapped even in the chiral limit, in seeming contradiction to the Goldstone theorem. Finally, we have a first look at the effect of thermal fluctuations of the CSL, showing that even the soft nonrelativistic excitation does not lead to the Landau-Peierls instability. However, it leads to an anomalous contribution to pressure that scales with temperature and magnetic field as T 5/2( B/f π )3/2.

  7. Fluid vs. kinetic magnetic reconnection with strong guide fields

    SciTech Connect

    Stanier, A. Simakov, Andrei N.; Chacón, L.; Daughton, W.

    2015-10-15

    The fast rates of magnetic reconnection found in both nature and experiments are important to understand theoretically. Recently, it was demonstrated that two-fluid magnetic reconnection remains fast in the strong guide field regime, regardless of the presence of fast-dispersive waves. This conclusion is in agreement with recent results from kinetic simulations, and is in contradiction to the findings in an earlier two-fluid study, where it was suggested that fast-dispersive waves are necessary for fast reconnection. In this paper, we give a more detailed derivation of the analytic model presented in a recent letter and present additional simulation results to support the conclusions that the magnetic reconnection rate in this regime is independent of both collisional dissipation and system-size. In particular, we present a detailed comparison between fluid and kinetic simulations, finding good agreement in both the reconnection rate and overall length of the current layer. Finally, we revisit the earlier two-fluid study, which arrived at different conclusions, and suggest an alternative interpretation for the numerical results presented therein.

  8. Photoionization of the hydrogen atom in strong magnetic fields

    NASA Technical Reports Server (NTRS)

    Potekhin, Aleksandr IU.; Pavlov, George G.

    1993-01-01

    The photoionization of the hydrogen atom in magnetic fields B about 10 exp 11 - 10 exp 13 G typical of the surface layers of neutron stars is investigated analytically and numerically. We consider the photoionization from various tightly bound and hydrogen-like states of the atom for photons with arbitrary polarizations and wave-vector directions. It is shown that the length form of the interaction matrix elements is more appropriate in the adiabatic approximation than the velocity form, at least in the most important frequency range omega much less than omega(B), where omega(B) is the electron cyclotron frequency. Use of the length form yields nonzero cross sections for photon polarizations perpendicular to the magnetic field at omega less than omega(B); these cross sections are the ones that most strongly affect the properties of the radiation escaping from an optically thick medium, e.g., from the atmosphere of a neutron star. The results of the numerical calculations are fitted by simple analytical formulas.

  9. Laser cooling at low intensity in a strong magnetic field

    NASA Astrophysics Data System (ADS)

    van der Straten, P.; Shang, S.-Q.; Sheehy, B.; Metcalf, H.; Nienhuis, G.

    1993-05-01

    We have studied theoretically and experimentally the effect of a relatively strong magnetic field on sub-Doppler laser cooling in a one-dimensional optical molasses. We used the operator description of laser cooling with the Larmor precession frequency ωZ being much higher than the optical pumping rate. We found velocity-selective resonances (VSR) in the force at velocities vr=nωZ, with n=0,+/-1,+/-2 for both the scattering and redistribution force operators. These depend on the relative direction of the magnetic field and the polarization vectors of the light beams. Analytical results for the force on the atom are obtained in two cases that illustrate the effect of the VSR on the force. These formulas are compared with numerical calculations of the force. We also discovered a redistribution mechanism that relies on the gradient of the eigenstates of the light-shift operator, with eigenvalues that are independent of position so that a ``Sisyphus cooling'' picture does not apply. The theory is compared with many experimental results and excellent agreement is found. We believe that all essential features of laser cooling at low intensity are well described by this operator theory.

  10. Chiral spiral induced by a strong magnetic field

    NASA Astrophysics Data System (ADS)

    Abuki, Hiroaki

    2016-11-01

    We study the modification of the chiral phase structure of QCD due to an external magnetic field. We first demonstrate how the effect of magnetic field can systematically be incorporated into a generalized Ginzburg-Landau framework. We then analyze the phase structure in the vicinity of the chiral critical point. In the chiral limit, the effect is found to be so drastic that it brings a "continent" of chiral spiral in the phase diagram, by which the chiral tricritical point is totally washed out. This is the case no matter how small the intensity of magnetic field is. On the other hand, the current quark mass protects the chiral critical point from a weak magnetic field. However, the critical point will eventually be covered by the chiral spiral phase as the magnetic field grows.

  11. Photon splitting in strong magnetic fields: S-matrix calculations

    NASA Astrophysics Data System (ADS)

    Weise, Jeanette I.; Baring, Matthew G.; Melrose, Donald B.

    1998-05-01

    The S-matrix approach to the treatment of photon splitting in a magnetized vacuum, with the electron propagators expressed in the Landau representation, is discussed critically. Although the analytic results of Mentzel, Berg and Wunner are confirmed, we propose that their available numerical results may be subject to two previously unidentified sources of error associated with the sum over principal quantum number n, leading to spurious contributions to the amplitude, and the extremely slow convergence of the sum for weak fields. It is shown how the sums may be rearranged to avoid the spurious contributions. If the Euler-Maclaurin summation formula is used to evaluate the infinite sums over n, the S-matrix approach then reproduces results derived by the effective Lagrangian and proper-time techniques in the weak-field, low-frequency limit. This method gives reliable results, for B>~0.01 and ω<~0.1, that reproduce those obtained by proper-time techniques. The S-matrix approach simplifies in the strong-field limit, B>>1, where the sum over n converges rapidly. Our results show that the branching ratio for the splittings ⊥-->⊥⊥ and ⊥-->∥∥ decreases from its known value ~3.4 for B<<1 towards zero for B>>1. For weak fields the S-matrix approach is unnecessarily cumbersome, and future numerical work should be based on the alternative approaches.

  12. Elevator mode convection in flows with strong magnetic fields

    NASA Astrophysics Data System (ADS)

    Liu, Li; Zikanov, Oleg

    2015-04-01

    Instability modes in the form of axially uniform vertical jets, also called "elevator modes," are known to be the solutions of thermal convection problems for vertically unbounded systems. Typically, their relevance to the actual flow state is limited by three-dimensional breakdown caused by rapid growth of secondary instabilities. We consider a flow of a liquid metal in a vertical duct with a heated wall and strong transverse magnetic field and find elevator modes that are stable and, thus, not just relevant, but a dominant feature of the flow. We then explore the hypothesis suggested by recent experimental data that an analogous instability to modes of slow axial variation develops in finite-length ducts, where it causes large-amplitude fluctuations of temperature. The implications for liquid metal blankets for tokamak fusion reactors that potentially invalidate some of the currently pursued design concepts are discussed.

  13. Elevator mode convection in flows with strong magnetic fields

    SciTech Connect

    Liu, Li; Zikanov, Oleg

    2015-04-15

    Instability modes in the form of axially uniform vertical jets, also called “elevator modes,” are known to be the solutions of thermal convection problems for vertically unbounded systems. Typically, their relevance to the actual flow state is limited by three-dimensional breakdown caused by rapid growth of secondary instabilities. We consider a flow of a liquid metal in a vertical duct with a heated wall and strong transverse magnetic field and find elevator modes that are stable and, thus, not just relevant, but a dominant feature of the flow. We then explore the hypothesis suggested by recent experimental data that an analogous instability to modes of slow axial variation develops in finite-length ducts, where it causes large-amplitude fluctuations of temperature. The implications for liquid metal blankets for tokamak fusion reactors that potentially invalidate some of the currently pursued design concepts are discussed.

  14. Deformed neutron stars due to strong magnetic field in terms of relativistic mean field theories

    NASA Astrophysics Data System (ADS)

    Yanase, Kota; Yoshinaga, Naotaka

    2014-09-01

    Some observations suggest that magnetic field intensity of neutron stars that have particularly strong magnetic field, magnetars, reaches values up to 1014-15G. It is expected that there exists more strong magnetic field of several orders of magnitude in the interior of such stars. Neutron star matter is so affected by magnetic fields caused by intrinsic magnetic moments and electric charges of baryons that masses of neutron stars calculated by using Tolman-Oppenheimer-Volkoff equation is therefore modified. We calculate equation of state (EOS) in density-dependent magnetic field by using sigma-omega-rho model that can reproduce properties of stable nuclear matter in laboratory Furthermore we calculate modified masses of deformed neutron stars.

  15. Neutrino emissivity from electron-positron annihilation in hot matter in a strong magnetic field

    SciTech Connect

    Amsterdamski, P.; Haensel, P. )

    1990-10-15

    The neutrino emissivity due to electron-positron annihilation in a strong magnetic field is computed. A strong magnetic field can significantly increase the neutrino emissivity at {ital T}{similar to}10{sup 9} K.

  16. Motion of particles of magnetically hard powder in a constant magnetic and strongly nonuniform electromagnetic fields

    SciTech Connect

    Bitkina, N.S.; Vernigorov, Yu.M.; Ignatov, B.P.; Lemeshko, G.F.

    1988-04-01

    The breakup process of floccules in the fluid state under the action of a constant magnetic and of strongly nonuniform electromagnetic fields was described and recorded by comparing the magnetic properties of samples pressed from powders, texturized, and prefluidized. Commercial barium ferrite powder was fluidized in a dielectric mold. A vibration magnetometer measured the magnetic properties. To evaluate the role of the resonance response to magnetic properties, a system of magnetic strings was formed and held in an oscillation regime induced by an alternating field with different frequency. It was found from the results of these formations that the magnetic structure of the sample consists of magnetic strings formed predominantly by separate particles and whose magnetic moments are oriented along the direction of the texturizing field. Results are also given for the fluidization of samarium-cobalt and samarium-cobalt-copper alloy powders.

  17. Magnetic field distribution of strong hybrid magnet in high torque motor

    NASA Astrophysics Data System (ADS)

    Oguri, Kazuya; Mizutani, Akihiro; Ogino, Sanshiroh; Ochiai, Yasuzumi; Kawahata, Masahiro; Nishi, Yoshitake

    2002-11-01

    A variable reluctance hybrid magnet has been developed to apply new type of high torque motors. A permanent magnet, electromagnet and yoke construct the variable reluctance hybrid magnet. From an engineering point of view, it is important to know the magnetic field around a variable reluctance hybrid magnet. Based on the results of magnetic flux density measurement around the hybrid variable reluctance magnet, the high magnetic flux density was found at edges and joints. The high magnetic flux density was also obtained with electrical current of 10 A at optimum setting form. Therefore, we concluded that the strong force of rotor of the hybrid motor was generated by high surface flux density of the hybrid magnet.

  18. Strong dipole magnetic fields in fast rotating fully convective stars

    NASA Astrophysics Data System (ADS)

    Shulyak, D.; Reiners, A.; Engeln, A.; Malo, L.; Yadav, R.; Morin, J.; Kochukhov, O.

    2017-08-01

    M dwarfs are the most numerous stars in our Galaxy, with masses between approximately 0.5 and 0.1 solar masses. Many of them show surface activity qualitatively similar to our Sun and generate flares, high X-ray fluxes and large-scale magnetic fields1,2,3,4. Such activity is driven by a dynamo powered by the convective motions in their interiors2,5,6,7,8. Understanding properties of stellar magnetic fields in these stars finds a broad application in astrophysics, including theory of stellar dynamos and environment conditions around planets that may be orbiting these stars. Most stars with convective envelopes follow a rotation-activity relationship where various activity indicators saturate in stars with rotation periods shorter than a few days2,6,8. The activity gradually declines with rotation rate in stars rotating more slowly. It is thought that, due to a tight empirical correlation between X-ray radiance and magnetic flux9, the stellar magnetic fields will also saturate, to values around 4 kG (ref. 10). Here we report the detection of magnetic fields above the presumed saturation limit in four fully convective M dwarfs. By combining results from spectroscopic and polarimetric studies, we explain our findings in terms of bistable dynamo models11,12: stars with the strongest magnetic fields are those in a dipole dynamo state, whereas stars in a multipole state cannot generate fields stronger than about 4 kG. Our study provides observational evidence that the dynamo in fully convective M dwarfs generates magnetic fields that can differ not only in the geometry of their large-scale component, but also in the total magnetic energy.

  19. Properties of mesons in a strong magnetic field.

    PubMed

    Zhang, Rui; Fu, Wei-Jie; Liu, Yu-Xin

    By extending the [Formula: see text]-derivable approach in the Nambu-Jona-Lasinio model to a finite magnetic field we calculate the properties of pion, [Formula: see text], and [Formula: see text] mesons in a magnetic field at finite temperature not only in the quark-antiquark bound state scheme but also in the pion-pion scattering resonant state scenario. Our calculation as a result makes manifest that the masses of [Formula: see text] and [Formula: see text] meson can be nearly degenerate at the pseudo-critical temperature which increases with increasing magnetic field strength, and the [Formula: see text] mass ascends suddenly at almost the same critical temperature. Meanwhile the [Formula: see text] mesons' masses decrease with the temperature but increase with the magnetic field strength. We also check the Gell-Mann-Oakes-Renner relation and find that the relation can be violated clearly with increasing temperature, and the effect of the magnetic field becomes pronounced around the critical temperature. With different criteria, we analyze the effect of the magnetic field on the chiral phase transition and find that the pseudo-critical temperature of the chiral phase cross, [Formula: see text], is always enhanced by the magnetic field. Moreover, our calculations indicate that the [Formula: see text] mesons will get melted as the chiral symmetry has not yet been restored, but the [Formula: see text] meson does not disassociate even at very high temperature. Particularly, it is the first to show that there does not exist a vector meson condensate in the QCD vacuum in the pion-pion scattering scheme.

  20. Dosimetry in the presence of strong magnetic fields

    NASA Astrophysics Data System (ADS)

    O'Brien, D. J.; Schupp, N.; Pencea, S.; Dolan, J.; Sawakuchi, G. O.

    2017-05-01

    Magnetic resonance imaging-guided radiotherapy (MRIgRT) is an emerging technology that requires the use of radiation fields in the presence of magnetic (B) fields. In the presence of B-fields the Lorentz force influences the trajectories of the secondary electrons, which in turn affects both the dose distribution in water and the dose-response of ionization chambers and several other detectors. Thus, dosimetry in the presence of a B-field requires understanding both the B-field effects on the dose distribution and the response of detectors. In this paper we present measured data to show effects of the B-field on the dose distributions, response of ionization chambers, and presence of air-gaps surrounding the sensitive volume of the detector.

  1. The embryonic development of frogs under strong DC magnetic fields

    SciTech Connect

    Ueno, S.; Harada, K.; Shiodawa, K.

    1984-09-01

    Possible influence of d.c. magnetic fields in the early embryonic development of frogs was studied. Embryos of African clawed toads, Xenopus laevis, were exposed to 1.0 T magnetic fields with different gradients of a range from 10 T/m to 10/sup 3/ T/m either during cleavage to neurula stage, blastula to neurula stage, or neurula to tail bud stage. The developmental processes of embryos during and after magnetic field exposures were followed to examine a possibility of teratogenic effects. The results suggest that the magnetic field exerts no harmful or modifying effects on the important morphogenetic movements such as gastrulation and neurulation. However, it was observed that embryos which were exposed to the gradient magnetic fields during cleavage to neurula stage occasionally developed into tadpoles with reduced pigmentation or some axial anomalies such as the formation of curled tail. Tadpoles with edema or microcephaly were also observed. Compared with the control, the rate of malformation was higher by about 35 %. The influence of oxygen concentration in Ringer's solution on the embryonic development was also studied, and toxicity of oxygen with high concentration is discussed.

  2. Plasma waves in a relativistic, strongly anisotropic plasma propagated along a strong magnetic field

    NASA Technical Reports Server (NTRS)

    Onishchenko, O. G.

    1980-01-01

    The dispersion properties of plasma waves in a relativistic homogeneous plasma propagated along a strong magnetic field are studied. It is shown that the non-damping plasma waves exist in the frequency range omega sub p or = omega or = omega sub L. The values of omega sub p and omega sub L are calculated for an arbitrary homogeneous relativistic function of the particle distribution. In the case of a power ultrarelativistic distribution, it is shown that, if the ultrarelativistic tail of the distribution drops very rapidly, slightly damping plasma waves are possible with the phase velocity (omega/K)c.

  3. Hydrogen in strong magnetic fields in neutron star surfaces

    NASA Astrophysics Data System (ADS)

    Salpeter, Edwin E.

    1998-12-01

    In magnetic fields of very much more than 0953-8984/10/49/017/img1 G, polyatomic hydrogen molecules, in the form of long chains, are stable. In neutron star surfaces, fields of 0953-8984/10/49/017/img2 G are commonplace and 0953-8984/10/49/017/img3 G has been reported. Liquid hydrogen can form at the higher field with a zero-pressure density of about 0953-8984/10/49/017/img4. At these densities, hydrogen can burn to helium by pycnonuclear reactions even at low temperatures - the `real cold fusion'.

  4. Strong Magnetic Field Induced Changes of Gene Expression in Arabidopsis

    NASA Astrophysics Data System (ADS)

    Paul, A.-L.; Ferl, R. J.; Klingenberg, B.; Brooks, J. S.; Morgan, A. N.; Yowtak, J.; Meisel, M. W.

    2005-07-01

    We review our studies of the biological impact of magnetic field strengths of up to 30 T on transgenic arabidopsis plants engineered with a stress response gene consisting of the alcohol dehydrogenase (Adh) gene promoter driving the β-glucuronidase (GUS) gene reporter. Field strengths in excess of 15 T induce expression of the Adh/GUS transgene in the roots and leaves. Microarray analyses indicate that such field strengths have a far reaching effect on the genome. Wide spread induction of stress-related genes and transcription factors, and a depression of genes associated with cell wall metabolism are prominent examples.

  5. Skin temperature changes induced by strong static magnetic field exposure.

    PubMed

    Ichioka, Shigeru; Minegishi, Masayuki; Iwasaka, Masakazu; Shibata, Masahiro; Nakatsuka, Takashi; Ando, Joji; Ueno, Shoogo

    2003-09-01

    High intensity static magnetic fields, when applied to the whole body of the anesthetized rat, have previously been reported to decrease skin temperature. The hypothesis of the present study was that in diamagnetic water, molecules in the air play significant roles in the mechanism of skin temperature decrease. We used a horizontal cylindrical superconducting magnet. The magnet produced 8 T at its center. A thermistor probe was inserted in a subcutaneous pocket of the anesthetized rats to measure skin temperature. Animals (n=10) were placed in an open plastic holder in which the ambient air was free to move in any direction (group I). Animals (n=10) were placed in a closed holder in which the air circulation toward the direction of weak magnetic field was restricted (group II). Each holder was connected to a hydrometer to measure humidity around the animal in the holder. The data acquisition phase consisted of a 5 min baseline interval, followed by inserting the animal together with the holder into the center of the magnet bore for a 5 min exposure and a 5 min postexposure period outside the bore. In group I, skin temperature and humidity around the animal significantly decreased during exposure, followed by recovery after exposure. In group II, skin temperature and humidity did not decrease during the measurement. The skin temperature decrease was closely related to the decrease in humidity around the body of the animal in the holder, and the changes were completely blocked by restricting the air circulation in the direction of the bore entrance. Possible mechanisms responsible for the decrease in skin temperature may be associated with magnetically induced movement of water vapor at the skin surface, leading to skin temperature decrease. Copyright 2003 Wiley-Liss, Inc.

  6. Back Compton Scattering in Strong Uniform Magnetic Field

    SciTech Connect

    Xu, W.; Huang Wei; Yan Mulin

    2006-11-02

    In this paper, we show that there is a Non-Commutative Plane (NCP) in the perpendicular magnetic fields in the accelerator, and the QED with NCP (QED-NCP) has been formulated. Being similar to the theory of quantum Hall effects, an effective filling factor f(B) is introduced, which characters the possibility occupied the LLL state by the electrons living on NCP. The back Compton scattering amplitudes of QED-NCP are derived, and the differential cross sections for the process with fixed initial polarizing electrons and photons are calculated. We propose to precisely measure the polarization dependent differential cross sections of the back Compton scattering in the perpendicular magnetic fields experimentally, which may lead to reveal the effects of QED with NCP. This should be interesting and remarkable. The existing Spring-8's data have been analyzed primitively, and some hints for QED-NCP effects are seen.

  7. A very strong magnetic field region in NOAA 11035

    NASA Astrophysics Data System (ADS)

    Jaeggli, Sarah Amelia

    2015-04-01

    NOAA 11035 was a fairly typical active region that emerged near the central meridian 13-14 December 2009, early in solar cycle 24. During the active region’s rapid emergence and evolution, a deeply-rooted magnetic bipole emerged into the pre-existing leading polarity with spectacular consequences. Multi-wavelength imaging and spectropolarimetry from FIRS, IBIS, Hinode, TRACE, and SOHO allow for a comprehensive investigation of the physical processes present in this region. Intrusion of the opposite polarity into the leading sunspot’s penumbra resulted in a region of highly concentrated horizontal magnetic field, with a peak field strength larger than 3600 G based on Milne-Eddington inversion of Fe I spectropolarimetry at 6302 and 15650 Å. Photospheric velocity measurements show blueshifts of 4 km/sec along the neutral line, which are coincident with a dark chromospheric structure in He I 10830 and H I 6563 Å. We conclude that these signatures are the result of continuous magnetic reconnection near photospheric heights.

  8. Strong Nonuniform Magnetic Field for Self-Diffusion Measurement by NMR in the Earth's Magnetic-Field

    NASA Astrophysics Data System (ADS)

    Stepisnik, J.; Kos, M.; Planinsic, G.; Erzen, V.

    Self-diffusion measurement by NMR requires a magnetic-field gradient that is strong enough to cause sufficient dephasing of the signal of migrating spins in the time of its application. The spin-relaxation mechanism limits the duration of the gradient field, and whenever particle migration is slow, the strength of the required inhomogeneous magnetic field may exceed that of the main magnetic field. In this case, the definition of the magnetic-field gradient fails and the usual formula for self-diffusion attenuation of spin echoes is no longer valid. This always happens with NMR in the earth's weak magnetic field. In the paper an expression for the self-diffusion attenuation of the spin echo is derived that is valid for a strong nonuniform magnetic field, and it is shown that the nonuniform magnetic field must have the appropriate spatial symmetry and that only isotropic self-diffusion can be measured with the new method. NMR measurement in the earth's magnetic field of the self-diffusion constants in some liquids confirms these results.

  9. Collisional excitation of electron Landau levels in strong magnetic fields

    NASA Technical Reports Server (NTRS)

    Langer, S. H.

    1981-01-01

    The cross sections for the excitation and deexcitation of the quantized transverse energy levels of an electron in a magnetic field are calculated for electron-proton and electron-electron collisions in light of the importance of the cross sections for studies of X-ray pulsar emission. First-order matrix elements are calculated using the Dirac theory of the electron, thus taking into account relativistic effects, which are believed to be important in accreting neutron stars. Results for the collisional excitation of ground state electrons by protons are presented which demonstrate the importance of proton recoil and relativistic effects, and it is shown that electron-electron excitations may contribute 10 to 20% of the excitation rate from electron-proton scattering in a Maxwellian plasma. Finally, calculations of the cross section for electron-proton small-angle scattering are presented which lead to relaxation rates for the electron velocity distribution which are modified by the magnetic field, and to a possible increase in the value of the Coulomb logarithm.

  10. Women are more strongly affected by dizziness in static magnetic fields of magnetic resonance imaging scanners.

    PubMed

    Heinrich, Angela; Szostek, Anne; Meyer, Patric; Reinhard, Iris; Gilles, Maria; Paslakis, Georgios; Rauschenberg, Jaane; Gröbner, Jens; Semmler, Wolfhard; Deuschle, Michael; Meyer-Lindenberg, Andreas; Flor, Herta; Nees, Frauke

    2014-10-01

    Increasing field strengths in MRI necessitate the examination of potential side effects. Previously reported results have been contradictory, possibly caused by imbalanced samples. We aimed to examine whether special groups of people are more prone to develop side effects that might have led to contradictory results in previous studies. We examined the occurrence of sensory side effects in static magnetic fields of MRI scanners of 1.5, 3, and 7 T and a mock scanner in 41 healthy participants. The contribution of field strength, sex, age, and attention to bodily processes, and stress hormone levels to the sensation of dizziness was examined in separate univariate analyses and in a joint analysis that included all variables. Field strength and sex were significant factors in the joint analysis (P=0.001), with women being more strongly affected than men by dizziness in higher static magnetic fields. This effect was not mediated by the other variables such as attention to bodily symptoms or stress hormones. Further research needs to elucidate the underlying factors of increased dizziness in women in static magnetic fields in MRI. We hypothesize that imbalanced samples of earlier studies might be one reason for previous contradictory results on the side effects of static magnetic fields.

  11. Sharp-front wave of strong magnetic field diffusion in solid metal

    SciTech Connect

    Xiao, Bo; Gu, Zhuo-wei; Kan, Ming-xian; Wang, Gang-hua; Zhao, Jian-heng

    2016-08-15

    When a strong magnetic field diffuses into a solid metal, if the metal's resistance possesses an abrupt rise at some critical temperature and the magnetic field strength is above some critical value, the magnetic field will diffuse into the metal in the form of a sharp-front wave. Formulas for the critical conditions under which a sharp-front magnetic diffusion wave emerges and a formula for the wave-front velocity are derived in this work.

  12. Strong-field atomic ionization in an elliptically polarized laser field and a constant magnetic field

    NASA Astrophysics Data System (ADS)

    Rylyuk, V. M.

    2016-05-01

    Within the framework of the quasistationary quasienergy state (QQES) formalism, the tunneling and multiphoton ionization of atoms and ions subjected to a perturbation by a high intense laser radiation field of an arbitrary polarization and a constant magnetic field are considered. On the basis of the exact solution of the Schrödinger equation and the Green's function for the electron moving in an arbitrary laser field and crossed constant electric and magnetic fields, the integral equation for the complex quasienergy and the energy spectrum of the ejected electron are derived. Using the "imaginary-time" method, the extremal subbarrier trajectory of the photoelectron moving in a nonstationary laser field and a constant magnetic field are considered. Within the framework of the QQES formalism and the quasiclassical perturbation theory, ionization rates when the Coulomb interaction of the photoelectron with the parent ion is taken into account at arbitrary values of the Keldysh parameter are derived. The high accuracy of rates is confirmed by comparison with the results of numerical calculations. Simple analytical expressions for the ionization rate with the Coulomb correction in the tunneling and multiphoton regimes in the case of an elliptically polarized laser beam propagating at an arbitrary angle to the constant magnetic field are derived and discussed. The limits of small and large magnetic fields and low and high frequency of a laser field are considered in details. It is shown that in the presence of a nonstationary laser field perturbation, the constant magnetic field may either decrease or increase the ionization rate. The analytical consideration and numerical calculations also showed that the difference between the ionization rates for an s electron in the case of right- and left-elliptically polarized laser fields is especially significant in the multiphoton regime for not-too-high magnetic fields and decreases as the magnetic field increases. The paper

  13. Suppression of cooling by strong magnetic fields in white dwarf stars.

    PubMed

    Valyavin, G; Shulyak, D; Wade, G A; Antonyuk, K; Zharikov, S V; Galazutdinov, G A; Plachinda, S; Bagnulo, S; Machado, L Fox; Alvarez, M; Clark, D M; Lopez, J M; Hiriart, D; Han, Inwoo; Jeon, Young-Beom; Zurita, C; Mujica, R; Burlakova, T; Szeifert, T; Burenkov, A

    2014-11-06

    Isolated cool white dwarf stars more often have strong magnetic fields than young, hotter white dwarfs, which has been a puzzle because magnetic fields are expected to decay with time but a cool surface suggests that the star is old. In addition, some white dwarfs with strong fields vary in brightness as they rotate, which has been variously attributed to surface brightness inhomogeneities similar to sunspots, chemical inhomogeneities and other magneto-optical effects. Here we describe optical observations of the brightness and magnetic field of the cool white dwarf WD 1953-011 taken over about eight years, and the results of an analysis of its surface temperature and magnetic field distribution. We find that the magnetic field suppresses atmospheric convection, leading to dark spots in the most magnetized areas. We also find that strong fields are sufficient to suppress convection over the entire surface in cool magnetic white dwarfs, which inhibits their cooling evolution relative to weakly magnetic and non-magnetic white dwarfs, making them appear younger than they truly are. This explains the long-standing mystery of why magnetic fields are more common amongst cool white dwarfs, and implies that the currently accepted ages of strongly magnetic white dwarfs are systematically too young.

  14. Suppression of cooling by strong magnetic fields in white dwarf stars

    NASA Astrophysics Data System (ADS)

    Valyavin, G.; Shulyak, D.; Wade, G. A.; Antonyuk, K.; Zharikov, S. V.; Galazutdinov, G. A.; Plachinda, S.; Bagnulo, S.; Fox Machado, L.; Alvarez, M.; Clark, D. M.; Lopez, J. M.; Hiriart, D.; Han, Inwoo; Jeon, Young-Beom; Zurita, C.; Mujica, R.; Burlakova, T.; Szeifert, T.; Burenkov, A.

    2014-11-01

    Isolated cool white dwarf stars more often have strong magnetic fields than young, hotter white dwarfs, which has been a puzzle because magnetic fields are expected to decay with time but a cool surface suggests that the star is old. In addition, some white dwarfs with strong fields vary in brightness as they rotate, which has been variously attributed to surface brightness inhomogeneities similar to sunspots, chemical inhomogeneities and other magneto-optical effects. Here we describe optical observations of the brightness and magnetic field of the cool white dwarf WD 1953-011 taken over about eight years, and the results of an analysis of its surface temperature and magnetic field distribution. We find that the magnetic field suppresses atmospheric convection, leading to dark spots in the most magnetized areas. We also find that strong fields are sufficient to suppress convection over the entire surface in cool magnetic white dwarfs, which inhibits their cooling evolution relative to weakly magnetic and non-magnetic white dwarfs, making them appear younger than they truly are. This explains the long-standing mystery of why magnetic fields are more common amongst cool white dwarfs, and implies that the currently accepted ages of strongly magnetic white dwarfs are systematically too young.

  15. Generation of strong magnetic fields in dense quark matter driven by the electroweak interaction of quarks

    NASA Astrophysics Data System (ADS)

    Dvornikov, Maxim

    2016-12-01

    We study the generation of strong large scale magnetic fields in dense quark matter. The magnetic field growth is owing to the magnetic field instability driven by the electroweak interaction of quarks. We discuss the situation when the chiral symmetry is unbroken in the degenerate quark matter. In this case we predict the amplification of the seed magnetic field 1012G to the strengths (1014 -1015)G. In our analysis we use the typical parameters of the quark matter in the core of a hybrid star or in a quark star. We also discuss the application of the obtained results to describe the magnetic fields generation in magnetars.

  16. Turbulent Magnetic Field Amplification behind Strong Shock Waves in GRB and SNR

    NASA Astrophysics Data System (ADS)

    Inoue, Tsuyoshi

    2012-09-01

    Using three-dimensional (special relativistic) magnetohydrodynamics simulations, the amplification of magnetic field behind strong shock wave is studied. In supernova remnants and gamma-ray bursts, strong shock waves propagate through an inhomogeneous density field. When the shock wave hit a density bump or density dent, the Richtmyer-Meshkov instability is induced that cause a deformation of the shock front. The deformed shock leaves vorticity behind the shock wave that amplifies the magnetic field due to the stretching of field lines.

  17. Decreased chemotaxis of human peripheral phagocytes exposed to a strong static magnetic field.

    PubMed

    Sipka, S; Szöllosi, I; Batta, Gy; Szegedi, Gy; Illés, A; Bakó, Gy; Novák, D

    2004-01-01

    The chemotaxis of human peripheral phagocytes, neutrophils and monocytes was examined in a strong static magnetic field (0.317+/-0.012 Tesla). The chemotaxis of the suspension of purified neutrophils and monocytes was tested in the Boyden chamber using C5a as a chemotactic signal. The chambers were placed into a temperature regulated (36.6 degrees C) equipment producing a strong static magnetic field (0.317 Tesla) for 60 minutes. The movement of cells proceeded into a nitrocellulose membrane toward the north-pole of the magnet, i.e. in the direction of the Earth's gravitational pull. The C5a induced chemotaxis of human neutrophils decreased significantly in the strong static magnetic field. Monocytes were not significantly effected. The strong static magnetic field decreased the chemotactic movement of neutrophils and this phenomenon may have implications when humans are exposed to magnetic resonance imaging for extended periods of time.

  18. Poisson-Vlasov in a strong magnetic field: A stochastic solution approach

    SciTech Connect

    Vilela Mendes, R.

    2010-04-15

    Stochastic solutions are obtained for the Maxwell-Vlasov equation in the approximation where magnetic field fluctuations are neglected and the electrostatic potential is used to compute the electric field. This is a reasonable approximation for plasmas in a strong external magnetic field. Both Fourier and configuration space solutions are constructed.

  19. Impact of Strong Magnetic Fields on Collision Mechanism for Transport of Charged Particles

    NASA Astrophysics Data System (ADS)

    Bostan, Mihai; Gamba, Irene M.

    2012-09-01

    One of the main applications in plasma physics concerns the energy production through thermo-nuclear fusion. The controlled fusion is achieved by magnetic confinement i.e., the plasma is confined into a toroidal domain (tokamak) under the action of huge magnetic fields. Several models exist for describing the evolution of strongly magnetized plasmas, most of them by neglecting the collisions between particles. The subject matter of this paper is to investigate the effect of large magnetic fields with respect to a collision mechanism. We consider here linear collision Boltzmann operators and derive, by averaging with respect to the fast cyclotronic motion due to strong magnetic forces, their effective collision kernels.

  20. SU-E-T-368: Effect of a Strong Magnetic Field On Select Radiation Dosimeters

    SciTech Connect

    Mathis, M; Wen, Z; Tailor, R; Sawakuchi, G; Flint, D; Beddar, S; Ibbott, G

    2014-06-01

    Purpose: To determine the effect of a strong magnetic field on TLD-100, OSLD (Al{sub 2}O{sub 2}:C), and PRESAGE dosimetry devices. This study will help to determine which types of dosimeters can be used for quality assurance and in-vivo dosimetry measurements in a magnetic resonance imaginglinear accelerator (MRI-linac) system. Methods: The dosimeters were separated into two categories which were either exposed or not exposed to a strong magnetic field. In each category a set of dosimeters was irradiated with 0, 2, or 6 Gy. To expose the dosimeters to a magnetic field the samples in that category were place in a Bruker small animal magnetic resonance scanner at a field strength slightly greater than 2.5 T for at least 1 hour preirradiation and at least 1 hour post-irradiation. Irradiations were performed with a 6 MV x-ray beam from a Varian TrueBeam linac with 10×10 cm{sup 2} field at a 600 MU/min dose rate. The samples that received no radiation dose were used as control detectors. Results: The readouts of the dosimeters which were not exposed to a strong magnetic field were compared with the measurements of the dosimetry devices which were exposed to a magnetic field. No significant differences (less than 2% difference) in the performance of TLD, OSLD, or PRESAGE dosimeters due to exposure to a strong magnetic field were observed. Conclusion: Exposure to a strong magnetic field before and after irradiation does not appear to change the dosimetric properties of TLD, OSLD, or PRESAGE which indicates that these dosimeters have potential for use in quality assurance and in-vivo dosimetry in a MRI-linac. We plan to further test the effect of magnetic fields on these devices by irradiating them in the presence of a magnetic fields similar to those produced by a MRI-linac system. Elekta-MD Anderson Cancer Center Research Agreement.

  1. Magnetohydrodynamics of laser-produced high-energy-density plasma in a strong external magnetic field.

    PubMed

    Matsuo, Kazuki; Nagatomo, Hideo; Zhang, Zhe; Nicolai, Philippe; Sano, Takayoshi; Sakata, Shohei; Kojima, Sadaoki; Lee, Seung Ho; Law, King Fai Farley; Arikawa, Yasunobu; Sakawa, Youichi; Morita, Taichi; Kuramitsu, Yasuhiro; Fujioka, Shinsuke; Azechi, Hiroshi

    2017-05-01

    Recent progress in the generation in the laboratory of a strong (>100-T) magnetic field enables us to investigate experimentally unexplored magnetohydrodynamics phenomena of a high-energy-density plasma, which an external magnetic field of 200-300 T notably affects due to anisotropic thermal conduction, even when the magnetic field pressure is much lower than the plasma pressure. The external magnetic field reduces electron thermal conduction across the external magnetic field lines because the Larmor radius of the thermal electrons in the external magnetic field is much shorter than the mean free path of the thermal electrons. The velocity of a thin polystyrene foil driven by intense laser beams in the strong external magnetic field is faster than that in the absence of the external magnetic field. Growth of sinusoidal corrugation imposed initially on the laser-driven polystyrene surface is enhanced by the external magnetic field because the plasma pressure distribution becomes nonuniform due to the external magnetic-field structure modulated by the perturbed plasma flow ablated from the corrugated surface.

  2. Magnetohydrodynamics of laser-produced high-energy-density plasma in a strong external magnetic field

    NASA Astrophysics Data System (ADS)

    Matsuo, Kazuki; Nagatomo, Hideo; Zhang, Zhe; Nicolai, Philippe; Sano, Takayoshi; Sakata, Shohei; Kojima, Sadaoki; Lee, Seung Ho; Law, King Fai Farley; Arikawa, Yasunobu; Sakawa, Youichi; Morita, Taichi; Kuramitsu, Yasuhiro; Fujioka, Shinsuke; Azechi, Hiroshi

    2017-05-01

    Recent progress in the generation in the laboratory of a strong (>100 -T) magnetic field enables us to investigate experimentally unexplored magnetohydrodynamics phenomena of a high-energy-density plasma, which an external magnetic field of 200-300 T notably affects due to anisotropic thermal conduction, even when the magnetic field pressure is much lower than the plasma pressure. The external magnetic field reduces electron thermal conduction across the external magnetic field lines because the Larmor radius of the thermal electrons in the external magnetic field is much shorter than the mean free path of the thermal electrons. The velocity of a thin polystyrene foil driven by intense laser beams in the strong external magnetic field is faster than that in the absence of the external magnetic field. Growth of sinusoidal corrugation imposed initially on the laser-driven polystyrene surface is enhanced by the external magnetic field because the plasma pressure distribution becomes nonuniform due to the external magnetic-field structure modulated by the perturbed plasma flow ablated from the corrugated surface.

  3. Wigner function and kinetic phenomena for chiral plasma in a strong magnetic field

    NASA Astrophysics Data System (ADS)

    Gorbar, E. V.; Miransky, V. A.; Shovkovy, I. A.; Sukhachov, P. O.

    2017-08-01

    By using the exact solutions of the Weyl equation in a constant magnetic field, the equal-time Wigner function for magnetized chiral plasma is derived. It is found that the dependence of the Wigner function on the component of momentum along the magnetic field is asymmetric and is correlated with the fermion chirality. Such a dependence is principal for reproducing the correct chiral magnetic and chiral separation effects. In the lowest Landau level approximation, the equation for the equal-time Wigner function in a strong magnetic field is derived. By making use of this equation, it is found that the longitudinal collective modes in a strong magnetic field are gapped plasmons whose gap is determined by the magnetic field. Unlike the ordinary magnetic field, an axial one allows for the dispersion law of the collective excitations asymmetric in the wave vector. The thermoelectric phenomena for chiral fermions in strong magnetic and axial magnetic fields are studied and the corresponding transport coefficients are calculated.

  4. Thin accretion discs are stabilized by a strong magnetic field

    NASA Astrophysics Data System (ADS)

    Sądowski, Aleksander

    2016-07-01

    By studying three-dimensional, radiative, global simulations of sub-Eddington, geometrically thin (H/R ≈ 0.15) black hole accretion flows we show that thin discs which are dominated by magnetic pressure are stable against thermal instability. Such discs are thicker than predicted by the standard model and show significant amount of dissipation inside the marginally stable orbit. Radiation released in this region, however, does not escape to infinity but is advected into the black hole. We find that the resulting accretion efficiency (5.5 ± 0.5 per cent for the simulated 0.8dot{M}_Edd disc) is very close to the predicted by the standard model (5.7 per cent).

  5. On the decay of strong magnetization in global disc simulations with toroidal fields

    NASA Astrophysics Data System (ADS)

    Fragile, P. Chris; Sądowski, Aleksander

    2017-05-01

    Strong magnetization in accretion discs could resolve a number of outstanding issues related to stability and state transitions in low-mass X-ray binaries. However, it is unclear how real discs become strongly magnetized and, even if they do, whether they can remain in such a state. In this paper, we address the latter issue through a pair of global disc simulations. Here, we only consider cases of initially purely toroidal magnetic fields contained entirely within a compact torus. We find that over only a few tens of orbital periods, the magnetization of an initially strongly magnetized disc, Pmag/Pgas ≥ 10, drops to ≲ 0.1, similar to the steady-state value reached in initially weakly magnetized discs. This is consistent with recent shearing box simulations with initially strong toroidal fields, the robust conclusion being that strongly magnetized toroidal fields cannot be locally self-sustaining. These results appear to leave net poloidal flux or extended radial fields as the only avenues for establishing strongly magnetized discs, ruling out the thermal collapse scenario.

  6. Biological effects of electromagnetic fields and recently updated safety guidelines for strong static magnetic fields.

    PubMed

    Yamaguchi-Sekino, Sachiko; Sekino, Masaki; Ueno, Shoogo

    2011-01-01

    Humans are exposed daily to artificial and naturally occurring magnetic fields that originate from many different sources. We review recent studies that examine the biological effects of and medical applications involving electromagnetic fields, review the properties of static and pulsed electromagnetic fields that affect biological systems, describe the use of a pulsed electromagnetic field in combination with an anticancer agent as an example of a medical application that incorporates an electromagnetic field, and discuss the recently updated safety guidelines for static electromagnetic fields. The most notable modifications to the 2009 International Commission on Non-Ionizing Radiation Protection guidelines are the increased exposure limits, especially for those who work with or near electromagnetic fields (occupational exposure limits). The recommended increases in exposure were determined using recent scientific evidence obtained from animal and human studies. Several studies since the 1994 publication of the guidelines have examined the effects on humans after exposure to high static electromagnetic fields (up to 9.4 tesla), but additional research is needed to ascertain further the safety of strong electromagnetic fields.

  7. Evaluation of diamagnetic nanofluid ability to heat transfer in the strong magnetic field

    NASA Astrophysics Data System (ADS)

    Roszko, A.; Fornalik-Wajs, E.

    2016-09-01

    The main goal of this paper was to analyze the strong magnetic field influence on the diamagnetic fluids. The experimental analysis of thermo-magnetic convection of silver nanofluid and distilled water were presented. The effect of various magnetic induction values and various temperature differences on the transport processes were checked. Estimation of the heat transfer was able due to the thermoelement signal analysis. The results revealed changes in the convection due to the nanoparticles addition in some ranges stronger, in other weaker, under applied conditions. It was proven, that heat transfer of diamagnetic fluid (single and two- phase) could be influenced by the strong magnetic field application.

  8. Parametric distortion of the optical absorption edge of a magnetic semiconductor by a strong laser field

    SciTech Connect

    Nunes, O.A.C.

    1985-09-15

    The influence of a strong laser field on the optical absorption edge of a direct-gap magnetic semiconductor is considered. It is shown that as the strong laser intensity increases the absorption coefficient is modified so as to give rise to an absorption tail below the free-field forbidden gap. An application is made for the case of the EuO.

  9. Polyakov loop and heavy quark entropy in strong magnetic fields from holographic black hole engineering

    NASA Astrophysics Data System (ADS)

    Critelli, Renato; Rougemont, Romulo; Finazzo, Stefano I.; Noronha, Jorge

    2016-12-01

    We investigate the temperature and magnetic field dependence of the Polyakov loop and heavy quark entropy in a bottom-up Einstein-Maxwell-dilaton (EMD) holographic model for the strongly coupled quark-gluon plasma that quantitatively matches lattice data for the (2 +1 )-flavor QCD equation of state at finite magnetic field and physical quark masses. We compare the holographic EMD model results for the Polyakov loop at zero and nonzero magnetic fields and the heavy quark entropy at vanishing magnetic field with the latest lattice data available for these observables and find good agreement for temperatures T ≳150 MeV and magnetic fields e B ≲1 GeV2 . Predictions for the behavior of the heavy quark entropy at nonzero magnetic fields are made that could be readily tested on the lattice.

  10. Formation of Antihydrogen Rydberg atoms in strong magnetic field traps

    SciTech Connect

    Pohl, T.; Sadeghpour, H. R.

    2008-08-08

    It is shown that several features of antihydrogen production in nested Penning traps can be described with accurate and efficient Monte Carlo simulations. It is found that cold deeply-bound Rydberg states of antihydrogen (H-bar) are produced in three-body capture in the ATRAP experiments and an additional formation mechanism -Rydberg charge transfer-, particular to the nested Penning trap geometry, is responsible for the observed fast (hot) H-bar atoms. Detailed description of the numerical propagation technique for following extreme close encounters is given. An analytic derivation of the power law behavior of the field ionization spectrum is provided.

  11. The effect of strong static magnetic field on lymphocytes.

    PubMed

    Aldinucci, Carlo; Garcia, Julian Blanco; Palmi, Mitri; Sgaragli, Gianpietro; Benocci, Alberto; Meini, Antonella; Pessina, Federica; Rossi, Claudio; Bonechi, Claudia; Pessina, Gian Paolo

    2003-02-01

    We investigated whether static electromagnetic fields (EMFs) at a flux density of 4.75 T, generated by an NMR apparatus (NMRF), could promote movements of Ca2+, cell proliferation, and the eventual production of proinflammatory cytokines in human peripheral blood mononuclear cells (PBMC) as well as in Jurkat cells, after exposure to the field for 1 h. The same study was also performed after activation of cells with 5 mg/ml phytohaemagglutinin (PHA). Our results clearly demonstrate that static NMRF exposure has neither proliferative, nor activating, nor proinflammatory effects on both normal and PHA activated PBMC. Moreover, the concentration of interleukin-1beta, interleukin-2, interleukin-6, interferon, and tumour necrosis factor alpha (TNFalpha) remained unvaried in exposed cells. Exposure of Jurkat cells statistically decreased the proliferation and the proliferation indexes, which 24 and 48 h after exposure were 0.7 +/- 0.29 and 0.87 +/- 0.12, respectively. Moreover, in Jurkat cells the [Ca2+]i was higher than in PBMC and was reduced significantly to about one half after exposure. This is consistent with the decrease of proliferation and with the low levels of IL-2 measured. On the whole, our data suggest that NMRF exposure failed to affect the physiologic behaviour of normal lymphomonocytes. Instead in Jurkat cells, by changing the properties of cell membranes, NMRF can influence Ca2+ transport processes, and hence Ca2+ homeostasis with improvement of proliferation.

  12. From inverse to delayed magnetic catalysis in a strong magnetic field

    NASA Astrophysics Data System (ADS)

    Mao, Shijun

    2016-08-01

    We study the magnetic field effect on chiral phase transition in a Nambu-Jona-Lasinio model. In comparison with a mean-field approximation containing only quarks, including mesons as quantum fluctuations in the model leads to a transition from inverse to delayed magnetic catalysis at finite temperature and delays the transition at finite baryon chemical potential. The location of the critical end point depends nonmonotonically on the magnetic field.

  13. Low Reynolds number flow's heat transfer influenced by strong magnetic field

    NASA Astrophysics Data System (ADS)

    Pleskacz, L.; Fornalik-Wajs, E.

    2016-09-01

    For the last 20 years research concerning the strong magnetic field influence on the weakly magnetic substances has been dynamically developing. The published papers refer mainly to natural convection problems connected with the impact of strong magnetic field. This paper follows previous Authors’ approach to forced convection modification by the additional magnetic force. Presently, attention was paid to the heat transfer processes and their quality assessment done in the basis of Nusselt number for low Reynolds number flow. The analysis was done for the geometry from Graetz-Brinkman problem with the magnetic coil located at the position of adiabatic-thermal boundary condition change. The numerical analysis was performed with Ansys software and application of the user-defined functions. Presented results revealed the influence of magnetic field on the flow structure and heat transfer.

  14. Light bending by nonlinear electrodynamics under strong electric and magnetic field

    SciTech Connect

    Kim, Jin Young; Lee, Taekoon E-mail: tlee@kunsan.ac.kr

    2011-11-01

    We calculate the bending angles of light under the strong electric and magnetic fields by a charged black hole and a magnetized neutron star according to the nonlinear electrodynamics of Euler-Heisenberg interaction. The bending angle of light by the electric field of charged black hole is computed from geometric optics and a general formula is derived for light bending valid for any orientation of the magnetic dipole. The astronomical significance of the light bending by magnetic field of a neutron star is discussed.

  15. Magnetic field induced by strong transverse plasmons in ultra-relativistic electron-positron plasmas

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Li, X. Q.; Liu, S. Q.

    2012-08-01

    Context. We investigated the generation of localized magnetic fields in an ultra-relativistic non-isothermal electron-positron plasma by strong electromagnetic plasmons. Aims: The results obtained can be used to explain the origin of small-scale magnetic fields in the internal shock region of gamma-ray bursts with ultra-relativistic electron positron plasmas. Methods: The generation of magnetic fields was investigated with kinetic Vlasov Maxwell equations. Results: The self-generated magnetic field will collapse for modulation instability, leading to spatially highly intermittent magnetic fluxes, whose characteristic scale is much larger than relativistic plasma skin depth, which in turn is conducive to the generation of the long-life small-scale magnetic fields in the internal shock region of gamma-ray bursts.

  16. Strong magnetic field-assisted growth of carbon nanofibers and its microstructural transformation mechanism

    PubMed Central

    Luo, Chengzhi; Fu, Qiang; Pan, Chunxu

    2015-01-01

    It is well-known that electric and magnetic fields can control the growth direction, morphology and microstructure of one-dimensional carbon nanomaterials (1-DCNMs), which plays a key role for its potential applications in micro-nano-electrics and devices. In this paper, we introduce a novel process for controlling growth of carbon nanofibers (CNFs) with assistance of a strong magnetic field (up to 0.5 T in the center) in a chemical vapor deposition (CVD) system. The results reveal that: 1) The CNFs get bundled when grown in the presence of a strong magnetic field and slightly get aligned parallel to the direction of the magnetic field; 2) The CNFs diameter become narrowed and homogenized with increase of the magnetic field; 3) With the increase of the magnetic field, the microstructure of CNFs is gradually changed, i.e., the strong magnetic field makes the disordered “solid-cored” CNFs transform into a kind of bamboo-liked carbon nanotubes; 4) We propose a mechanism that the reason for these variations and transformation is due to diamagnetic property of carbon atoms, so that it has direction selectivity in the precipitation process. PMID:25761381

  17. Strong magnetic field-assisted growth of carbon nanofibers and its microstructural transformation mechanism

    NASA Astrophysics Data System (ADS)

    Luo, Chengzhi; Fu, Qiang; Pan, Chunxu

    2015-03-01

    It is well-known that electric and magnetic fields can control the growth direction, morphology and microstructure of one-dimensional carbon nanomaterials (1-DCNMs), which plays a key role for its potential applications in micro-nano-electrics and devices. In this paper, we introduce a novel process for controlling growth of carbon nanofibers (CNFs) with assistance of a strong magnetic field (up to 0.5 T in the center) in a chemical vapor deposition (CVD) system. The results reveal that: 1) The CNFs get bundled when grown in the presence of a strong magnetic field and slightly get aligned parallel to the direction of the magnetic field; 2) The CNFs diameter become narrowed and homogenized with increase of the magnetic field; 3) With the increase of the magnetic field, the microstructure of CNFs is gradually changed, i.e., the strong magnetic field makes the disordered ``solid-cored'' CNFs transform into a kind of bamboo-liked carbon nanotubes; 4) We propose a mechanism that the reason for these variations and transformation is due to diamagnetic property of carbon atoms, so that it has direction selectivity in the precipitation process.

  18. Asteroseismology can reveal strong internal magnetic fields in red giant stars.

    PubMed

    Fuller, Jim; Cantiello, Matteo; Stello, Dennis; Garcia, Rafael A; Bildsten, Lars

    2015-10-23

    Internal stellar magnetic fields are inaccessible to direct observations, and little is known about their amplitude, geometry, and evolution. We demonstrate that strong magnetic fields in the cores of red giant stars can be identified with asteroseismology. The fields can manifest themselves via depressed dipole stellar oscillation modes, arising from a magnetic greenhouse effect that scatters and traps oscillation-mode energy within the core of the star. The Kepler satellite has observed a few dozen red giants with depressed dipole modes, which we interpret as stars with strongly magnetized cores. We find that field strengths larger than ~10(5) gauss may produce the observed depression, and in one case we infer a minimum core field strength of ≈10(7) gauss. Copyright © 2015, American Association for the Advancement of Science.

  19. Asteroseismology can reveal strong internal magnetic fields in red giant stars

    NASA Astrophysics Data System (ADS)

    Fuller, Jim; Cantiello, Matteo; Stello, Dennis; Garcia, Rafael A.; Bildsten, Lars

    2015-10-01

    Internal stellar magnetic fields are inaccessible to direct observations, and little is known about their amplitude, geometry, and evolution. We demonstrate that strong magnetic fields in the cores of red giant stars can be identified with asteroseismology. The fields can manifest themselves via depressed dipole stellar oscillation modes, arising from a magnetic greenhouse effect that scatters and traps oscillation-mode energy within the core of the star. The Kepler satellite has observed a few dozen red giants with depressed dipole modes, which we interpret as stars with strongly magnetized cores. We find that field strengths larger than ~105 gauss may produce the observed depression, and in one case we infer a minimum core field strength of ≈107 gauss.

  20. Color-flavor locked strange quark matter in a strong magnetic field

    NASA Astrophysics Data System (ADS)

    Wen, Xin-Jian

    2013-08-01

    The quark quasiparticle model is extended to study the properties of color-flavor locked strange quark matter at finite chemical potential and in a strong magnetic field. We present a self-consistent thermodynamic treatment by employing a chemical potential dependent bag function. It is found that the magnetized color-flavor locked (MCFL) matter is more stable than other phases within a proper magnitude of magnetic field. The stability window is graphically shown for the MCFL matter compared with ordinate magnetized matter. The anisotropic structure of MCFL matter is dominated by the magnetic field and almost independent of the energy gaps. A critical maximum magnetic field of about 1.56×1018G is found, under which MCFL matter is absolutely stable with respect to nuclear matter.

  1. Effect of Strong Orbital Magnetic Field on the Exciton Condensation in an Extended Falicov Kimball Model

    NASA Astrophysics Data System (ADS)

    Pradhan, S.; Taraphder, A.

    2016-10-01

    A spinless, extended Falicov-Kimball model in the presence of a perpendicular magnetic field is investigated employing a self-consistent mean-field theory in two dimensions. In the presence of the field the excitonic average Δ =< di † fi > is modified: the exciton responds in subtle different ways for different values of the magnetic flux. We examine the effects of Coulomb interaction and hybridization between the localized and itinerant electrons on the excitonic average, for rational values of the applied magnetic field. The excitonic average is found to get enhanced exponentially with the Coulomb interaction while it saturates at large hybridization. The orbital magnetic field suppresses the excitonic average in general, though a strong commensurability effect of the magnetic flux on the behaviour of the excitonic order parameter is observed.

  2. Gravitational mass and energy gradient in the ultra-strong magnetic fields

    NASA Astrophysics Data System (ADS)

    Weng, Zi-Hua

    2017-07-01

    The paper aims to apply the complex octonion to explore the influence of the energy gradient on the Eötvös experiment, impacting the gravitational mass in the ultra-strong magnetic fields. Until now the Eötvös experiment has never been validated under the ultra-strong magnetic field. It is aggravating the existing serious qualms about the Eötvös experiment. According to the electromagnetic and gravitational theory described with the complex octonions, the ultra-strong magnetic field must result in a tiny variation of the gravitational mass. The magnetic field with the gradient distribution will generate the energy gradient. These influencing factors will exert an influence on the state of equilibrium in the Eötvös experiment. That is, the gravitational mass will depart from the inertial mass to a certain extent, in the ultra-strong magnetic fields. Only under exceptional circumstances, especially in the case of the weak field strength, the gravitational mass may be equal to the inertial mass approximately. The paper appeals intensely to validate the Eötvös experiment in the ultra-strong electromagnetic strengths. It is predicted that the physical property of gravitational mass will be distinct from that of inertial mass.

  3. Effect of horizontal strong static magnetic field on swimming behaviour of Paramecium caudatum

    NASA Astrophysics Data System (ADS)

    Fujiwara, Yoshihisa; Tomishige, Masahiko; Itoh, Yasuhiro; Fujiwara, Masao; Shibata, Naho; Kosaka, Toshikazu; Hosoya, Hiroshi; Tanimoto, Yoshifumi

    2006-05-01

    Effect of horizontal strong static magnetic field on swimming behaviour of Paramecium caudatum was studied by using a superconducting magnet. Around a centre of a round vessel, random swimming at 0 T and aligned swimming parallel to the magnetic field (MF) of 8 T were observed. Near a wall of the vessel, however, swimming round and round along the wall at 0 T and aligned swimming of turning at right angles upon collision with the wall, which was remarkable around 1-4 T, were detected. It was experimentally revealed that the former MF-induced parallel swimming at the vessel centre was caused physicochemically by the parallel magnetic orientation of the cell itself. From magnetic field dependence of the extent of the orientation, the magnetic susceptibility anisotropy (χ ∥-χ ⊥) was first obtained to be 3.4× 10-23 emu cell-1 at 298 K for Paramecium caudatum. The orientation of the cell was considered to result from the magnetic orientation of the cell membrane. On the other hand, although mechanisms of the latter swimming near the vessel wall regardless of the absence and presence of the magnetic field are unclear at present, these experimental results indicate that whether the cell exists near the wall alters the magnetic field effect on the swimming in the horizontal magnetic field.

  4. Magnetized Fast ignition (MFI) and Laser Plasma Interactions in Strong Magnetic Field

    NASA Astrophysics Data System (ADS)

    Mima, Kunioki; Johzaki, T.; Honrubia, J.; Nagatomo, H.; Taguchi, T.; Sunahara, A.; Sakagami, H.; Fujioka, S.; Logan, G.

    2016-03-01

    In this paper, magnetized fast ignition (MFI) is proposed for improving the coupling efficiency of a heating laser to a core plasma. In the MFI, the external magnetic field is applied to reduce the hot electron energy and focus the dense hot electron flux to the core. The external magnetic field higher than 100T is generated by the laser driven coil and it is amplified by the implosion. The magnetic field at the tip of the cone is expected to reach higher than 10kT and the laser plasma interaction and the hot electron transport are modified. As the results of applying the external magnetic field, hot electron energy is reduced to less than 5MeV for the laser intensity of 1020W/ cm2 and the Weibel instability is suppressed to collimate the hot electron beam to the core.

  5. Spinodal instabilities and the distillation effect in nuclear matter under strong magnetic fields

    SciTech Connect

    Rabhi, A.; Providencia, C.; Providencia, J. Da

    2009-01-15

    We study the effect of strong magnetic fields, of the order of 10{sup 18}-10{sup 19} G, on the instability region of nuclear matter at subsaturation densities. Relativistic nuclear models both with constant couplings and with density-dependent parameters are considered. It is shown that a strong magnetic field can have large effects on the instability regions giving rise to bands of instability and wider unstable regions. As a consequence, we predict larger transition densities at the inner edge of the crust of compact stars with strong magnetic fields. The direction of instability gives rise to a very strong distillation effect if the last Landau level is only partially filled. However, for almost completed Landau levels, an antidistillation effect may occur.

  6. Neutron stars in a perturbative f(R) gravity model with strong magnetic fields

    SciTech Connect

    Cheoun, Myung-Ki; Deliduman, Cemsinan; Güngör, Can; Keleş, Vildan; Ryu, C.Y.; Kajino, Toshitaka; Mathews, Grant J. E-mail: cemsinan@msgsu.edu.tr E-mail: kelesvi@itu.edu.tr E-mail: kajino@nao.ac.jp

    2013-10-01

    In Kaluza-Klein electromagnetism it is natural to associate modified gravity with strong electromagnetic fields. Hence, in this paper we investigate the combined effects of a strong magnetic field and perturbative f(R) gravity on the structure of neutron stars. The effect of an interior strong magnetic field of about 10{sup 17−18} G on the equation of state is derived in the context of a quantum hadrodynamics (QHD) equation of state (EoS) including effects of the magnetic pressure and energy along with occupied Landau levels. Adopting a random orientation of interior field domains, we solve the modified spherically symmetric hydrostatic equilibrium equations derived for a gravity model with f(R) = R+αR{sup 2}. Effects of both the finite magnetic field and the modified gravity are detailed for various values of the magnetic field and the perturbation parameter α along with a discussion of their physical implications. We show that there exists a parameter space of the modified gravity and the magnetic field strength, in which even a soft equation of state can accommodate a large ( > 2 M{sub s}un) maximum neutron star mass.

  7. Strongly Interacting Matter in Magnetic Fields: A Guide to This Volume

    NASA Astrophysics Data System (ADS)

    Kharzeev, Dmitri E.; Landsteiner, Karl; Schmitt, Andreas; Yee, Ho-Ung

    This is an introduction to the volume of Lecture Notes in Physics on "Strongly interacting matter in magnetic fields". The volume combines contributions written by a number of experts on different aspects of the problem. The response of QCD matter to intense magnetic fields has attracted a lot of interest recently. On the theoretical side, this interest stems from the possibility to explore the plethora of novel phenomena arising from the interplay of magnetic field with QCD dynamics. On the experimental side, the interest is motivated by the recent results on the behavior of quark-gluon plasma in a strong magnetic field created in relativistic heavy ion collisions at RHIC and LHC. The purpose of this introduction is to provide a brief overview and a guide to the individual contributions where these topics are covered in detail.

  8. Equation of State of the Strong Interaction Matter in an External Magnetic Field

    NASA Astrophysics Data System (ADS)

    Zhang, Rui; Liu, Yu-Xin

    2015-10-01

    We investigate the equation of state of the strong interaction matter in a background magnetic field via the two flavor Nambu-Jona-Lasinio model. Starting from the mean-field thermodynamical potential density Ω, we calculate the pressure density p, the entropy density s, the energy density ɛ, and the interaction measure (ɛ - 3p)/T4 of the strong interaction matter at finite temperature and finite magnetic field. The results manifest that the chiral phase transition is just a crossover but not a low order phase transition. Moreover there may exist magnetic catalysis effect, and its mechanism is just the effective dimension reduction induced by the magnetic field. Supported by the National Natural Science Foundation of China under Grant Nos. 10935001, 11175004 and 11435001, and the National Key Basic Research Program of China under Grant Nos. G2013CB834400 and 2015CB856900

  9. Temperature Distribution in Two-Dimensional Electron Gases under a Strong Magnetic Field

    NASA Astrophysics Data System (ADS)

    Hirayama, Naomi; Endo, Akira; Fujita, Kazuhiro; Hasegawa, Yasuhiro; Hatano, Naomichi; Nakamura, Hiroaki; Shirasaki, Ryōen; Yonemitsu, Kenji

    2011-05-01

    Two-dimensional electron gases having an electrochemical potential gradient under a magnetic field are numerically examined using the finite-difference method. The temperature, voltage, electric current, and heat flux are calculated from transport equations describing thermoelectric and thermomagnetic effects, namely the Hall, Nernst, Ettingshausen, and Righi-Leduc effects. The results show that a magnetic field distorts equipotential lines and generates an uneven temperature distribution. In particular, a part of the system is found to become colder than the temperature of the heat baths. The cooling effect under a strong magnetic field is due primarily to the Ettingshausen and Hall effects.

  10. Tunnel effect in molecules in strong magnetic fields of neutron stars

    NASA Astrophysics Data System (ADS)

    Khersonskii, V. K.

    1982-10-01

    The penetration coefficient and probability of tunnel transition in molecular ions H(2+) and HD(+), as functions of the magnetic field in the region B = 10 to the 11th-10 to the 13th G, is calculated. It is found that in this strong, neutron star magnetic field, the probability of tunnel effect increases significantly. It is probable that such an effect can catalyze nuclear reactions at the neutron star surface.

  11. ON MULTIPLE RECONNECTION X-LINES AND TRIPOLAR PERTURBATIONS OF STRONG GUIDE MAGNETIC FIELDS

    SciTech Connect

    Eriksson, S.; Gosling, J. T.; Lapenta, G.; Newman, D. L.; Goldman, M. V.; Phan, T. D.; Lavraud, B.; Khotyaintsev, Yu. V.; Carr, C. M.; Markidis, S.

    2015-05-20

    We report new multi-spacecraft Cluster observations of tripolar guide magnetic field perturbations at a solar wind reconnection exhaust in the presence of a guide field B{sub M} {sub  }which is almost four times as strong as the reversing field B{sub L}. The novel tripolar field consists of two narrow regions of depressed B{sub M}, with an observed 7%–14% ΔB{sub M} magnitude relative to the external field, which are found adjacent to a wide region of enhanced B{sub M} within the exhaust. A stronger reversing field is associated with each B{sub M} depression. A kinetic reconnection simulation for realistic solar wind conditions and the observed strong guide field reveals that tripolar magnetic fields preferentially form across current sheets in the presence of multiple X-lines as magnetic islands approach one another and merge into fewer and larger islands. The simulated ΔB{sub M}/ΔX{sub N} over the normal width ΔX{sub N} between a B{sub M} minimum and the edge of the external region agree with the normalized values observed by Cluster. We propose that a tripolar guide field perturbation may be used to identify candidate regions containing multiple X-lines and interacting magnetic islands at individual solar wind current sheets with a strong guide field.

  12. Exposure to strong static magnetic field slows the growth of human cancer cells in vitro.

    PubMed

    Raylman, R R; Clavo, A C; Wahl, R L

    1996-01-01

    Proposals to enhance the amount of radiation dose delivered to small tumors with radioimmunotherapy by constraining emitted electrons with very strong homogeneous static magnetic fields has renewed interest in the cellular effects of prolonged exposures to such fields. Past investigations have not studied the effects on tumor cell growth of lengthy exposures to very high magnetic fields. Three malignant human cell lines, HTB 63 (melanoma), HTB 77 IP3 (ovarian carcinoma), and CCL 86 (lymphoma: Raji cells), were exposed to a 7 Tesla uniform static magnetic field for 64 hours. Following exposure, the number of viable cells in each group was determined. In addition, multicycle flow cytometry was performed on all cell lines, and pulsed-field electrophoresis was performed solely on Raji cells to investigate changes in cell cycle patterns and the possibility of DNA fragmentation induced by the magnetic field. A 64 h exposure to the magnetic field produced a reduction in viable cell number in each of the three cell lines. Reductions of 19.04 +/- 7.32%, 22.06 +/- 6.19%, and 40.68 +/- 8.31% were measured for the melanoma, ovarian carcinoma, and lymphoma cell lines, respectively, vs. control groups not exposed to the magnetic field. Multicycle flow cytometry revealed that the cell cycle was largely unaltered. Pulsed-field electrophoresis analysis revealed no increase in DNA breaks related to magnetic field exposure. In conclusion, prolonged exposure to a very strong magnetic field appeared to inhibit the growth of three human tumor cell lines in vitro. The mechanism underlying this effect has not, as yet, been identified, although alteration of cell growth cycle and gross fragmentation of DNA have been excluded as possible contributory factors. Future investigations of this phenomenon may have a significant impact on the future understanding and treatment of cancer.

  13. Geomagnetic and strong static magnetic field effects on growth and chlorophyll a fluorescence in Lemna minor.

    PubMed

    Jan, Luka; Fefer, Dušan; Košmelj, Katarina; Gaberščik, Alenka; Jerman, Igor

    2015-04-01

    The geomagnetic field (GMF) varies over Earth's surface and changes over time, but it is generally not considered as a factor that could influence plant growth. The effects of reduced and enhanced GMFs and a strong static magnetic field on growth and chlorophyll a (Chl a) fluorescence of Lemna minor plants were investigated under controlled conditions. A standard 7 day test was conducted in extreme geomagnetic environments of 4 µT and 100 µT as well as in a strong static magnetic field environment of 150 mT. Specific growth rates as well as slow and fast Chl a fluorescence kinetics were measured after 7 days incubation. The results, compared to those of controls, showed that the reduced GMF significantly stimulated growth rate of the total frond area in the magnetically treated plants. However, the enhanced GMF pointed towards inhibition of growth rate in exposed plants in comparison to control, but the difference was not statistically significant. This trend was not observed in the case of treatments with strong static magnetic fields. Our measurements suggest that the efficiency of photosystem II is not affected by variations in GMF. In contrast, the strong static magnetic field seems to have the potential to increase initial Chl a fluorescence and energy dissipation in Lemna minor plants.

  14. Magnetohydrodynamics of high-energy-density-plasma in strong magnetic field

    NASA Astrophysics Data System (ADS)

    Matsuo, Kazuki; Nagatomo, Hideo; Sano, Takayoshi; Zhang, Zhe; Sakawa, Youichi; Hara, Yukiko; Shimogawara, Hiroshi; Airikawa, Yasunobu; Sakata, Shouhei; Law, Kingfaifarley; Lee, Seungho; Kojima, Sadaoki; Katou, Hiroki; Shigemori, Keisuke; Fujioka, Shinsuke; Azechi, Hiroshi

    2016-10-01

    The magneto-hydrodynamics (MHD) of a high-energy-density-plasma (HEDP) in a strong external magnetic field contains a lot of fundamental and essential physics related to astro- and solar- physics and B-assisted inertial confinement fusion energy development. Especially, hydrodynamic instability in a strong magnetic field is a key physics for success of B-assisted inertial confinement fusion. Hydrodynamic instability growth is affected by strong magnetic field as a result of non-uniform heat flow. Experiments were conducted with a corrugated plastic target that is set between a pair of capacitor-coil. A pair of capacitor-coil targets was used to generate spatially uniform magnetic field. The plastic targets were irradiated by an intense laser pulse having 1013 W/cm2 of intensity. Temporal evolution of perturbation growth was observed with x-ray backlight technique. Enhancement of the perturbation growth in strong magnetic field was observed experimentally, and the result was consistent with hydrodynamic simulation.

  15. Osmolality dependence of erythrocyte sedimentation and aggregation in a strong magnetic field.

    PubMed

    Iino, M; Okuda, Y

    2001-01-01

    In order to specify the major determinant of the magnetic enhancement of erythrocyte sedimentation observed previously, the dependence of erythrocyte sedimentation rate (ESR) on osmolality was measured under a strong magnetic field. Even at hypotonic osmolality, an increase in ESR due to aggregation was observed in plasma solution as compared with that without aggregation in saline solution. However, the magnetic field did not enhance ESR at hypotonic osmolality, when the cell shape was an isotropic sphere (spherocyte). Thus, we narrowed our search to a mechanism that would explain the enhanced ESR found specifically in anisotropic erythrocytes. It was concluded that the major determinant can only work for anisotropic erythrocytes and is a magnetic field-induced increase in an intermembrane adhesive area due to magnetic orientation of anisotropic erythrocytes. Copyright 2001 Wiley-Liss, Inc.

  16. π0 pole mass calculation in a strong magnetic field and lattice constraints

    NASA Astrophysics Data System (ADS)

    Avancini, Sidney S.; Farias, Ricardo L. S.; Benghi Pinto, Marcus; Tavares, William R.; Timóteo, Varese S.

    2017-04-01

    The π0 neutral meson pole mass is calculated in a strongly magnetized medium using the SU(2) Nambu-Jona-Lasinio model within the random phase approximation (RPA) at zero temperature and zero baryonic density. We employ a magnetic field dependent coupling, G (eB), fitted to reproduce lattice QCD results for the quark condensates. Divergent quantities are handled with a magnetic field independent regularization scheme in order to avoid unphysical oscillations. A comparison between the running and the fixed couplings reveals that the former produces results much closer to the predictions from recent lattice calculations. In particular, we find that the π0 meson mass systematically decreases when the magnetic field increases while the scalar mass remains almost constant. We also investigate how the magnetic background influences other mesonic properties such as fπ0 and gπ0qq.

  17. The asteroseismic signature of strong magnetic fields in the cores of red giant stars

    NASA Astrophysics Data System (ADS)

    Fuller, Jim; Cantiello, Matteo; Stello, Dennis; Garcia, Rafael; Bildsten, Lars

    2016-01-01

    Internal stellar magnetic fields are inaccessible to direct observations and little is known about their amplitude, geometry and evolution. I will discuss how strong magnetic fields in the cores of red giant stars can be identified with asteroseismology. The fields manifest themselves via depressed dipole stellar oscillation modes, which arises from a magnetic greenhouse effect that scatters and traps oscillation mode energy within the core of the star. Physically, the effect stems from magnetic tension forces created by sufficiently strong fields, which break the spherical symmetry of the wave propagation cavity. The loss of wave energy within the core reduces the mode visibility at the stellar surface, and we find that our predicted visibilities are in excellent agreement with a class of red giants exhibiting depressed dipole oscillation modes. The Kepler satellite has already observed hundreds of these red giants, which we identify as stars with strongly magnetized cores. Field strengths larger than roughly 10^5 G can produce the observed depression, and in one case we measure a core field strength of 10^7 G.

  18. Polarized x-ray emission from magnetized neutron stars: signature of strong-field vacuum polarization.

    PubMed

    Lai, Dong; Ho, Wynn C G

    2003-08-15

    In the atmospheric plasma of a strongly magnetized neutron star, vacuum polarization can induce a Mikheyev-Smirnov-Wolfenstein type resonance across which an x-ray photon may (depending on its energy) convert from one mode into the other, with significant changes in opacities and polarizations. We show that this vacuum resonance effect gives rise to a unique energy-dependent polarization signature in the surface emission from neutron stars. The detection of polarized x rays from neutron stars can provide a direct probe of strong-field quantum electrodynamics and constrain the neutron star magnetic field and geometry.

  19. Chiral soliton lattice and charged pion condensation in strong magnetic fields

    NASA Astrophysics Data System (ADS)

    Brauner, Tomáš; Yamamoto, Naoki

    2017-04-01

    The Chiral Soliton Lattice (CSL) is a state with a periodic array of topological solitons that spontaneously breaks parity and translational symmetries. Such a state is known to appear in chiral magnets. We show that CSL also appears as a ground state of quantum chromodynamics at nonzero chemical potential in a magnetic field. By analyzing the fluctuations of the CSL, we furthermore demonstrate that in strong but achievable magnetic fields, charged pions undergo Bose-Einstein condensation. Our results, based on a systematic low-energy effective theory, are model-independent and fully analytic.

  20. Transport properties of bilayer graphene in a strong in-plane magnetic field

    NASA Astrophysics Data System (ADS)

    Van der Donck, M.; Peeters, F. M.; Van Duppen, B.

    2016-03-01

    A strong in-plane magnetic field drastically alters the low-energy spectrum of bilayer graphene by separating the parabolic energy dispersion into two linear Dirac cones. The effect of this dramatic change on the transport properties strongly depends on the orientation of the in-plane magnetic field with respect to the propagation direction of the charge carriers and the angle at which they impinge on the electrostatic potentials. For magnetic fields oriented parallel to the potential boundaries an additional propagating mode that results from the splitting into Dirac cones enhances the transmission probability for charge carriers tunneling through the potentials and increases the corresponding conductance. Our results show that the chiral suppression of transmission at normal incidence, reminiscent of bilayer graphene's 2 π Berry phase, is turned into a chiral enhancement when the magnetic field increases, thus indicating a transition from a bilayer to a monolayer-like system at normal incidence. Further, we find that the typical transmission resonances stemming from confinement in a potential barrier are shifted to higher energy and are eventually transformed into antiresonances with increasing magnetic field. For magnetic fields oriented perpendicular to the potential boundaries we find a very pronounced transition from a bilayer system to two separated monolayer-like systems with Klein tunneling emerging at certain incident angles symmetric around 0, which also leaves a signature in the conductance. For both orientations of the magnetic field, the transmission probability is still correctly described by pseudospin conservation. Finally, to motivate the large in-plane magnetic field, we show that its energy spectrum can be mimicked by specific lattice deformations such as a relative shift of one of the layers. With this equivalence we introduce the notion of an in-plane pseudomagnetic field.

  1. B field in OB stars (BOB): The outstandingly strong magnetic field in the evolved He-strong star CPD -62° 2124

    NASA Astrophysics Data System (ADS)

    Castro, N.; Fossati, L.; Hubrig, S.; Järvinen, S. P.; Przybilla, N.; Nieva, M.-F.; Ilyin, I.; Carroll, T. A.; Schöller, M.; Langer, N.; Schneider, F. R. N.; Simón-Díaz, S.; Morel, T.; Butler, K.; BOB Collaboration

    2017-01-01

    The origin and evolution of magnetism in OB stars is far from being well understood. With approximately 70 magnetic OB stars known, any new object with unusual characteristics may turn out to be a key piece of the puzzle. We report the detection of an exceptionally strong magnetic field in the He-strong B2IV star CPD -62° 2124. Spectropolarimetric FORS2 and HARPSpol observations were analysed by two independent teams and procedures, concluding on a strong longitudinal magnetic field of approximately 5.2 kG. The quantitative characterisation of the stellar atmosphere yields an effective temperature of 23 650 ± 250 K, a surface gravity of 3.95 ± 0.10 dex and a surface helium fraction of 0.35 ± 0.02 by number. The metal composition is in agreement with the cosmic abundance standard, except for Mg, Si and S, which are slightly non-solar. The strong and broad ( 300 km s-1) disc-like emission displayed by the Hα line suggests a centrifugal magnetosphere supported by the strong magnetic field. Our results imply that CPD -62° 2124 is an early B-type star hosting one of the strongest magnetic fields discovered to date, and one of the most evolved He-strong stars known, with a fractional main-sequence lifetime of approximately 0.6. Based on observations made with ESO telescopes at the La Silla and Paranal observatories under programme ID 191.D-0255(G,I).

  2. Strong Decay of ϕ (1 s), ϒ(4s) and Σ±*in Magnetic Field

    NASA Astrophysics Data System (ADS)

    Filip, Peter

    2016-01-01

    The influence of static magnetic field on decays ϕ (1020) KK̅, ϒ (4s)→ BB̅, and Σ±* → Ʌπ± is discussed. In particular, we estimate how much the ratio of decay widths Γ(K+K-)/Γ(K0K0) and Γ(B+B-)/Γ(B0B0) can be modified by magnetic fields of strength B ≈ 1014 T created in relativistic collisions of heavy nuclei at LHC and RHIC colliders. Due to interaction of charged K and B mesons with the magnetic field, branching ratios for K+K- and B+B- decays of ϕ (1020) and ϒ (4s) completely closed. We study also the influence of magnetic field on strong decay Σ±* (1385) →Ʌ + π±.

  3. On the theory of magnetic field generation by relativistically strong laser radiation

    SciTech Connect

    Berezhiani, V.I.; Shatashvili, N.L.; Mahajan, S.M. |

    1996-07-01

    The authors consider the interaction of subpicosecond relativistically strong short laser pulses with an underdense cold unmagnetized electron plasma. It is shown that the strong plasma inhomogeneity caused by laser pulses results in the generation of a low frequency (quasistatic) magnetic field. Since the electron density distribution is determined completely by the pump wave intensity, the generated magnetic field is negligibly small for nonrelativistic laser pulses but increases rapidly in the ultrarelativistic case. Due to the possibility of electron cavitation (complete expulsion of electrons from the central region) for narrow and intense beams, the increase in the generated magnetic field slows down as the beam intensity is increased. The structure of the magnetic field closely resembles that of the field produced by a solenoid; the field is maximum and uniform in the cavitation region, then it falls, changes polarity and vanishes. In extremely dense plasmas, highly intense laser pulses in the self-channeling regime can generate magnetic fields {approximately} 100 Mg and greater.

  4. A possible influence on standard model of quasars and active galactic nuclei in strong magnetic field

    NASA Astrophysics Data System (ADS)

    Peng, Qiu-He; Liu, Jing-Jing; Chou, Chi-Kang

    2016-12-01

    Recent observational evidence indicates that the center of our Milky Way galaxy harbors a super-massive object with ultra-strong radial magnetic field (Eatough et al. in Nature 591:391, 2013). Here we demonstrate that the radiations observed in the vicinity of the Galactic Center (GC) (Falcke and Marko in arXiv:1311.1841v1, 2013) cannot be emitted by the gas of the accretion disk since the accreting plasma is prevented from approaching to the GC by the abnormally strong radial magnetic field. These fields obstruct the infalling accretion flow from the inner region of the disk and the central massive black hole in the standard model. It is expected that the observed radiations near the GC can not be generated by the central black hole. We also demonstrate that the observed ultra-strong radial magnetic field near the GC (Eatough et al. in Nature 591:391, 2013) can not be generated by the generalized α-turbulence type dynamo mechanism since preliminary qualitative estimate in terms of this mechanism gives a magnetic field strength six orders of magnitude smaller than the observed field strength at r=0.12 pc. However, both these difficulties or the dilemma of the standard model can be overcome if the central black hole in the standard model is replaced by a model of a super-massive star with magnetic monopoles (SMSMM) (Peng and Chou in Astrophys. J. Lett. 551:23, 2001). Five predictions about the GC have been proposed in the SMSMM model. Especially, three of them are quantitatively consistent with the observations. They are: (1) Plenty of positrons are produced, the production rate is 6×10^{42} e+ s^{-1} or so, this prediction is confirmed by the observation (Kn ödlseder et al. 2003); (2) The lower limit of the observed ultra-strong radial magnetic field near the GC (Eatough et al. in Nature 591:391, 2013), is just good agreement with the predicted estimated radial magnetic field from the SMSMM model, which really is an exclusive and a key prediction; (3) The

  5. Quark matter under strong magnetic fields in the Nambu-Jona-Lasinio model

    SciTech Connect

    Menezes, D. P.; Pinto, M. Benghi; Avancini, S. S.; Martinez, A. Perez; Providencia, C.

    2009-03-15

    In the present work we use the large-N{sub c} approximation to investigate quark matter described by the SU(2) Nambu-Jona-Lasinio model subject to a strong magnetic field. The Landau levels are filled in such a way that usual kinks appear in the effective mass and other related quantities. {beta} equilibrium is also considered and the macroscopic properties of a magnetar described by this quark matter is obtained. Our study shows that the magnetar masses and radii are larger if the magnetic field increases but only very large fields ({>=}10{sup 18} G) affect the equation of state in a non-negligible way.

  6. Anisotropic heavy quark potential in strongly-coupled N =4 SYM theory in a magnetic field

    NASA Astrophysics Data System (ADS)

    Rougemont, R.; Critelli, R.; Noronha, J.

    2015-03-01

    In this work we use the gauge/gravity duality to study the anisotropy in the heavy quark potential in strongly coupled N =4 super-Yang Mills (SYM) theory (both at zero and nonzero temperature) induced by a constant and uniform magnetic field B . At zero temperature, the inclusion of the magnetic field decreases the attractive force between heavy quarks with respect to its B =0 value and the force associated with the parallel potential is the least attractive force. We find that the same occurs at nonzero temperature and, thus, at least in the case of strongly coupled N =4 SYM, the presence of a magnetic field generally weakens the interaction between heavy quarks in the plasma.

  7. First Detection of a Strong Magnetic Field on a Bursty Brown Dwarf: Puzzle Solved

    NASA Astrophysics Data System (ADS)

    Berdyugina, S. V.; Harrington, D. M.; Kuzmychov, O.; Kuhn, J. R.; Hallinan, G.; Kowalski, A. F.; Hawley, S. L.

    2017-09-01

    We report the first direct detection of a strong, 5 kG magnetic field on the surface of an active brown dwarf. LSR J1835+3259 is an M8.5 dwarf exhibiting transient radio and optical emission bursts modulated by fast rotation. We have detected the surface magnetic field as circularly polarized signatures in the 819 nm sodium lines when an active emission region faced the Earth. Modeling Stokes profiles of these lines reveals the effective temperature of 2800 K and log gravity acceleration of 4.5. These parameters place LSR J1835+3259 on evolutionary tracks as a young brown dwarf with the mass of 55+/- 4{M}{{J}} and age of 22 ± 4 Myr. Its magnetic field is at least 5.1 kG and covers at least 11% of the visible hemisphere. The active region topology recovered using line profile inversions comprises hot plasma loops with a vertical stratification of optical and radio emission sources. These loops rotate with the dwarf in and out of view causing periodic emission bursts. The magnetic field is detected at the base of the loops. This is the first time that we can quantitatively associate brown dwarf non-thermal bursts with a strong, 5 kG surface magnetic field and solve the puzzle of their driving mechanism. This is also the coolest known dwarf with such a strong surface magnetic field. The young age of LSR J1835+3259 implies that it may still maintain a disk, which may facilitate bursts via magnetospheric accretion, like in higher-mass T Tau-type stars. Our results pave a path toward magnetic studies of brown dwarfs and hot Jupiters.

  8. Electron cyclotron maser instability (ECMI) in strong magnetic guide field reconnection

    NASA Astrophysics Data System (ADS)

    Treumann, Rudolf A.; Baumjohann, Wolfgang

    2017-08-01

    The ECMI model of electromagnetic radiation from electron holes is shown to be applicable to spontaneous magnetic reconnection. We apply it to reconnection in strong current-aligned magnetic guide fields. Such guide fields participate only passively in reconnection, which occurs in the antiparallel components to both sides of the guide-field-aligned current sheets with current carried by kinetic Alfvén waves. Reconnection generates long (the order of hundreds of electron inertial scales) electron exhaust regions at the reconnection site X point, which are extended perpendicular to the current and the guide fields. Exhausts contain a strongly density-depleted hot electron component and have properties similar to electron holes. Exhaust electron momentum space distributions are highly deformed, exhibiting steep gradients transverse to both the reconnecting and guide fields. Such properties suggest application of the ECMI mechanism with the fundamental ECMI X-mode emission beneath the nonrelativistic guide field cyclotron frequency in localized source regions. An outline of the mechanism and its prospects is given. Potential applications are the kilometric radiation (AKR) in auroral physics, solar radio emissions during flares, planetary emissions and astrophysical scenarios (radiation from stars and compact objects) involving the presence of strong magnetic fields and field-aligned currents. Drift of the exhausts along the guide field maps the local field and plasma properties. Escape of radiation from the exhaust and radiation source region still poses a problem. The mechanism can be studied in 2-D particle simulations of strong guide field reconnection which favours 2-D, mapping the deformation of the electron distribution perpendicular to the guide field, and using it in the numerical calculation of the ECMI growth rate. The mechanism suggests also that reconnection in general may become a source of the ECMI with or without guide fields. This is of particular

  9. In-medium covariant propagator of baryons under a strong magnetic field: Effect of the intrinsic magnetic moments

    NASA Astrophysics Data System (ADS)

    Aguirre, R. M.; De Paoli, A. L.

    2016-11-01

    We obtain the covariant propagator at finite temperature for interacting baryons immersed in a strong magnetic field. The effect of the intrinsic magnetic moments on the Green function are fully taken into account. We make an expansion in terms of eigenfunctions of a Dirac field, which leads us to a compact form of its propagator. We present some simple applications of these propagators, where the statistical averages of nuclear currents and energy density are evaluated.

  10. The distant magnetotail's response to a strong interplanetary magnetic field By - Twisting, flattening, and field line bending

    NASA Technical Reports Server (NTRS)

    Sibeck, D. G.; Siscoe, G. L.; Slavin, J. A.; Smith, E. J.; Tsurutani, B. T.; Lepping, R. P.

    1985-01-01

    During an interval of strong interplanetary magnetic field (IMF) By, while ISEE 3 was in the distant magnetotail, the north lobe was observed south of the ecliptic plane. Lobe field lines were strongly bent in the direction of the IMF, and a dense boundary layer plasma was observed. During the interval, magnetopause normals pointed in the z direction, although ISEE 3 was near the dawnside ecliptic plane. The observations are interpreted in terms of field line bending within a twisted and flattened magnetotail.

  11. No evidence of a strong magnetic field in the Blazhko star RR Lyrae

    NASA Astrophysics Data System (ADS)

    Chadid, M.; Wade, G. A.; Shorlin, S. L. S.; Landstreet, J. D.

    2004-01-01

    In this paper we report a new series of high-precision (median σB˜ 80 G) longitudinal magnetic field measurements of RR Lyrae, the brightest Blazhko star, obtained with the MuSiCoS spectropolarimeter over a period of almost 4 years from 1999-2002. These data provide no evidence whatsoever for a strong magnetic field in the photosphere of RR Lyrae, a result consistent with Preston's (\\cite{Preston67}) results, but inconsistent with apparent magnetic field detections by Babcock (\\cite{Babcock58}) and Romanov et al. (\\cite{Romanov87}, \\cite{Romanov94}). Following discussion of these disparate results, we conclude that RR Lyrae is a {bona fide} non-magnetic star, a conclusion which leads to the general falsification of models of the Blazkho effect requiring strong photospheric magnetic fields. Furthermore, due to the 4 year baseline of our observations, we can also dismiss the hypothesis that RR Lyrae undergoes a 4-year ``magnetic cycle''. Therefore the origin of the observed 4-year modulation of RR Lyrae remains unexplained, and we stress the need for additional theoretical efforts to come to a better understanding of this phenomenon. Based on observations obtained with the MuSiCoS spectropolarimeter attached to the 2 m Bernard-Lyot Telescope of the Pic du Midi Observatory, France.

  12. The onset of ion heating during magnetic reconnection with a strong guide field

    SciTech Connect

    Drake, J. F.; Swisdak, M.

    2014-07-15

    The onset of the acceleration of ions during magnetic reconnection is explored via particle-in-cell simulations in the limit of a strong ambient guide field that self-consistently and simultaneously follow the motions of protons and α particles. Heating parallel to the local magnetic field during reconnection with a guide field is strongly reduced compared with the reconnection of anti-parallel magnetic fields. The dominant heating of thermal ions during guide field reconnection results from pickup behavior of ions during their entry into reconnection exhausts and dominantly produces heating perpendicular rather than parallel to the local magnetic field. Pickup behavior requires that the ion transit time across the exhaust boundary (with a transverse scale of the order of the ion sound Larmor radius) be short compared with the ion cyclotron period. This translates into a threshold in the strength of reconnecting magnetic field that favors the heating of ions with high mass-to-charge. A simulation with a broad initial current layer produces a reconnecting system in which the amplitude of the reconnecting magnetic field just upstream of the dissipation region increases with time as reconnection proceeds. The sharp onset of perpendicular heating when the pickup threshold is crossed is documented. A comparison of the time variation of the parallel and perpendicular ion heating with that predicted based on the strength of the reconnecting field establishes the scaling of ion heating with ambient parameters both below and above the pickup threshold. The relevance to observations of ion heating in the solar corona is discussed.

  13. Vacuum birefringence in strong magnetic fields: (II) Complex refractive index from the lowest Landau level

    SciTech Connect

    Hattori, Koichi; Itakura, Kazunori

    2013-07-15

    We compute the refractive indices of a photon propagating in strong magnetic fields on the basis of the analytic representation of the vacuum polarization tensor obtained in our previous paper. When the external magnetic field is strong enough for the fermion one-loop diagram of the polarization tensor to be approximated by the lowest Landau level, the propagating mode in parallel to the magnetic field is subject to modification: The refractive index deviates from unity and can be very large, and when the photon energy is large enough, the refractive index acquires an imaginary part indicating decay of a photon into a fermion–antifermion pair. We study dependences of the refractive index on the propagating angle and the magnetic-field strength. It is also emphasized that a self-consistent treatment of the equation which defines the refractive index is indispensable for accurate description of the refractive index. This self-consistent treatment physically corresponds to consistently including the effects of back reactions of the distorted Dirac sea in response to the incident photon. -- Highlights: •Vacuum birefringence and photon decay are described by the complex refractive index. •Resummed photon vacuum polarization tensor in the lowest Landau level is used. •Back reactions from the distorted Dirac sea are self-consistently taken into account. •Self-consistent treatment drastically changes structure in photon energy dependence. •Dependences on photon propagation angle and magnetic-field strength are presented.

  14. Dynamics of liquid metal droplets and jets influenced by a strong axial magnetic field

    NASA Astrophysics Data System (ADS)

    Hernández, D.; Karcher, Ch

    2017-07-01

    Non-contact electromagnetic control and shaping of liquid metal free surfaces is crucial in a number of high-temperature metallurgical processes like levitation melting and electromagnetic sealing, among others. Other examples are the electromagnetic bending or stabilization of liquid metal jets that frequently occur in casting or fusion applications. Within this context, we experimentally study the influence of strong axial magnetic fields on the dynamics of falling metal droplets and liquid metal jets. GaInSn in eutectic composition is used as test melt being liquid at room temperature. In the experiments, we use a cryogen-free superconducting magnet (CFM) providing steady homogeneous fields of up to 5 T and allowing a tilt angle between the falling melt and the magnet axis. We vary the magnetic flux density, the tilt angle, the liquid metal flow rate, and the diameter and material of the nozzle (electrically conducting/insulating). Hence, the experiments cover a parameter range of Hartmann numbers Ha, Reynolds numbers Re, and Weber numbers We within 0 < Ha < 440, 340 < Re < 4500, and 0.09 < We < 12.1. As major results we find that under the influence of the strong magnetic field, droplet rotation ceases and the droplets are stretched in the field direction. Moreover, we observe that the jet breakup into droplets (spheroidization) is suppressed, and in the case of electrically conducting nozzles and tilt, the jets are bent towards the field axis.

  15. Electron dynamics of a He atom in strong, oscillating magnetic fields

    NASA Astrophysics Data System (ADS)

    Sadhukhan, M.; Deb, B. M.

    2014-04-01

    The present numerical, time-dependent density-functional study of a He atom interacting with strong, oscillating magnetic fields shows that this scenario is quite different from the case of a laser electric field-He atom interaction. Signatures of sluggish electron dynamics are found in this study, while through a mechanical analogy the flow of electron density under such conditions has been explained. These calculations take into account both exchange and correlation. Through several calculated dynamical quantities, we have shown that, in contrast to the case of the (one-electron) H atom studied earlier, the nonlinear dependence of interelectronic repulsions (a combination of Coulomb, exchange and correlation terms) on the magnetic field plays a significant role in this strong-field electron dynamics in the He atom, which cannot be explained by a perturbative approach.

  16. STRONG SOLAR WIND DYNAMIC PRESSURE PULSES: INTERPLANETARY SOURCES AND THEIR IMPACTS ON GEOSYNCHRONOUS MAGNETIC FIELDS

    SciTech Connect

    Zuo, Pingbing; Feng, Xueshang; Wang, Yi; Xie, Yanqiong; Xu, Xiaojun E-mail: fengx@spaceweather.ac.cn

    2015-10-20

    In this investigation, we first present a statistical result of the interplanetary sources of very strong solar wind dynamic pressure pulses (DPPs) detected by WIND during solar cycle 23. It is found that the vast majority of strong DPPs reside within solar wind disturbances. Although the variabilities of geosynchronous magnetic fields (GMFs) due to the impact of positive DPPs have been well established, there appears to be no systematic investigations on the response of GMFs to negative DPPs. Here, we study both the decompression effects of very strong negative DPPs and the compression from strong positive DPPs on GMFs at different magnetic local time sectors. In response to the decompression of strong negative DPPs, GMFs on the dayside near dawn and near dusk on the nightside, are generally depressed. But near the midnight region, the responses of GMF are very diverse, being either positive or negative. For part of the events when GOES is located at the midnight sector, the GMF is found to abnormally increase as the result of magnetospheric decompression caused by negative DPPs. It is known that under certain conditions magnetic depression of nightside GMFs can be caused by the impact of positive DPPs. Here, we find that a stronger pressure enhancement may have a higher probability of producing the exceptional depression of GMF at the midnight region. Statistically, both the decompression effect of strong negative DPPs and the compression effect of strong positive DPPs depend on the magnetic local time, which are stronger at the noon sector.

  17. Unitary limit of two-nucleon interactions in strong magnetic fields

    DOE PAGES

    Detmold, William; Orginos, Kostas; Parreño, Assumpta; ...

    2016-03-14

    In this study, two-nucleon systems are shown to exhibit large scattering lengths in strong magnetic fields at unphysical quark masses, and the trends toward the physical values indicate that such features may exist in nature. Lattice QCD calculations of the energies of one and two nucleons systems are performed at pion masses of mπ ~ 450 and 806 MeV in uniform, time-independent magnetic fields of strength |B| ~ 1019 – 1020 Gauss to determine the response of these hadronic systems to large magnetic fields. Fields of this strength may exist inside magnetars and in peripheral relativistic heavy ion collisions, andmore » the unitary behavior at large scattering lengths may have important consequences for these systems.« less

  18. Unitary limit of two-nucleon interactions in strong magnetic fields

    SciTech Connect

    Detmold, William; Orginos, Kostas; Parreño, Assumpta; Savage, Martin J.; Tiburzi, Brian C.; Beane, Silas R.; Chang, Emmanuel

    2016-03-14

    In this study, two-nucleon systems are shown to exhibit large scattering lengths in strong magnetic fields at unphysical quark masses, and the trends toward the physical values indicate that such features may exist in nature. Lattice QCD calculations of the energies of one and two nucleons systems are performed at pion masses of mπ ~ 450 and 806 MeV in uniform, time-independent magnetic fields of strength |B| ~ 1019 – 1020 Gauss to determine the response of these hadronic systems to large magnetic fields. Fields of this strength may exist inside magnetars and in peripheral relativistic heavy ion collisions, and the unitary behavior at large scattering lengths may have important consequences for these systems.

  19. Catalysis of nuclear reactions in hydrogen in a strong magnetic field

    NASA Astrophysics Data System (ADS)

    Khersonskii, V. K.

    1986-10-01

    Calculations are made of the probabilities of nuclear reactions in HD(+), D2(+), and DT(+) molecular ions in a strong magnetic field. It is shown, that as the field intensity increases from 10 to the 12th to 10 to the 13 G, the probabilities of the nuclear reactions increase by ten orders of magnitude. The calculations allow for the effect of the vibrational-rotational state of the molecules on the reaction probabilities.

  20. Spin polarization in high density quark matter under a strong external magnetic field

    NASA Astrophysics Data System (ADS)

    Tsue, Yasuhiko; da Providência, João; Providência, Constança; Yamamura, Masatoshi; Bohr, Henrik

    In high density quark matter under a strong external magnetic field, possible phases are investigated by using the two-flavor Nambu-Jona-Lasinio (NJL) model with tensor-type four-point interaction between quarks, as well as the axial-vector-type four-point interaction. In the tensor-type interaction under the strong external magnetic field, it is shown that a quark spin polarized phase is realized in all regions of the quark chemical potential under consideration within the lowest Landau level approximation. In the axial-vector-type interaction, it is also shown that the quark spin polarized phase appears in the wide range of the quark chemical potential. In both the interactions, the quark mass in zero and small chemical potential regions increases which indicates that the chiral symmetry breaking is enhanced, namely the magnetic catalysis occurs.

  1. Oscillator strength spectrum of hydrogen in strong magnetic and electric fields with arbitrary mutual orientation

    SciTech Connect

    Guan Xiaoxu

    2006-08-15

    We present oscillator strength spectra of the hydrogen Balmer {alpha} series in crossed strong magnetic and electric fields. Field strength regimes of interest ({gamma}{<=}0.02 a.u. and F{<=}1x10{sup 8} V/m) are the characteristic strengths observed on the surface of white dwarf stars. Based on the pseudospectral discretization technique, two independent methods have been developed to achieve reliable oscillator strengths in crossed fields. The effect of relative orientation between the magnetic and electric fields is clarified. Compared to the parallel configuration, we have observed that for the field strength regimes of interest, the perpendicular component of electric fields only results in a weaker coupling between the states belonging to the different subspaces of magnetic quantum numbers. This observation explains why the spectrum of oscillator strengths in crossed electric and magnetic fields with arbitrary mutual orientation shows similar behavior compared to that in parallel fields. However, a careful analysis shows that the two stronger transition lines at 5546 and 5620 A ring previously attributed to the Balmer {alpha} series are now identified to belong to the Balmer {beta} series. An effective scheme has also been suggested to calculate the bound-free opacities of hydrogen atoms in crossed fields.

  2. Generation of strong magnetic field using 60 mm∅ superconducting bulk magnet and its application to magnetron sputtering device

    NASA Astrophysics Data System (ADS)

    Yanagi, Y.; Matsuda, T.; Hazama, H.; Yokouchi, K.; Yoshikawa, M.; Itoh, Y.; Oka, T.; Ikuta, H.; Mizutani, U.

    2005-10-01

    To make a practical application of a superconducting bulk magnet (SBM), it is necessary that the SBM generates a strong and stable magnetic field in a working space and the magnet can be handled without any special care that would be needed because of the use of a superconductor. To satisfy these requirements, we have designed a portable and user-friendly magnet system consisting of a small air-cooled type refrigerator and a bulk superconductor. By using the stress-controlling magnetization technique, we could achieve a magnetic flux density of 8.0 T on the bulk surface and 6.5 T over the vacuum chamber surface of the refrigerator, when a 60 mm∅ Gd-Ba-Cu-O bulk superconductor reinforced with a 5 mm thick stainless steel ring was magnetized by field cooling in 8.5 T to 27 K. We have confirmed that the bulk magnet system coupled with a battery is quite portable and can be delivered to any location by using a car with an electric power outlet in the cabin. We have constructed a magnetron sputtering device that employs a bulk magnet system delivered from the place of magnetization by this method. This sputtering device exhibits several unique features such as deposition at a very low Ar gas pressure because the magnetic field is 20 times stronger than that obtained by a conventional device in the working space.

  3. Bending of electromagnetic wave in an ultra-strong magnetic field

    NASA Astrophysics Data System (ADS)

    Kim, Jin Young

    2012-10-01

    We consider the bending of light by nonlinear electrodynamics when the magnetic field B exceeds the critical value Bc = m2c2/ehbar = 4.4 × 109T. Using the index of refraction derived from the analytic series representation in one-loop effective action of QED, we found the trajectory and the bending angle of light in geometric optics. The angle bent by ultra-strong magnetic field of magnetar was estimated and compared with the gravitational bending. The result may be useful in studying the lensing, birefringence, and other nonlinear quantum electrodynamic effects above Bc.

  4. Electron emission from self-assembled quantum dots in strong magnetic fields

    NASA Astrophysics Data System (ADS)

    Schramm, A.; Schulz, S.; Schaefer, J.; Zander, T.; Heyn, Ch.; Hansen, W.

    2006-05-01

    We probe with deep level transient spectroscopy electron states in self-assembled InAs quantum dots. Two pronounced maxima are observed that we associate with emission from different quantum-dot orbital states. Fine structure clearly establishes distinct emission rates for quantum dots with one or two electrons in the s state and up to four electrons in the p-like states. In order to confirm these assignments spectra have been recorded in strong magnetic fields. The observed magnetic field dispersion of the emission energies is described with a harmonic oscillator model using an effective electron mass of m*=0.03me.

  5. Experimental study of transport of relativistic electron beams in strong magnetic mirror field

    NASA Astrophysics Data System (ADS)

    Sakata, Shohei; Kondo, Kotaro; Bailly-Grandvaux, Mathiu; Bellei, Claudio; Santos, Joao; Firex Project Team

    2015-11-01

    Relativistic electron beams REB produced by ultra high intense laser pulses have generally a large divergence angle that results in degradation of energy coupling between the REB and a fuel core in the fast ignition scheme. Guiding and focusing of the REB by a strong external magnetic field was proposed to achieve high efficiency. We investigated REB transport through 50 μm or 250 μm thick plastic foils CuI doped under external magnetic fields, in magnetic mirror configurations of 1.2 or 4 mirror ratio. The experiment was carried out at the GEKKO XII and LFEX laser facility. Spatial pattern of the REB was measured by coherent transition radiation and/or Cu Ka x ray emission from the rear surface of the foil targets. Strong collimation of the REB by the external magnetic field was observed with 50 μm thick plastic targets, while the REB scattered in 250 μm thick targets. The experimental results are compared with computer simulations to understand the physical mechanisms of the REB transport in the external magnetic field. This work is supported by NIFS (Japan), MEXT/JSPS KAKENHI (Japan), JSPS Fellowship (Japan), ANR (France) and COST (Europe).

  6. Transport through a strongly coupled graphene quantum dot in perpendicular magnetic field

    PubMed Central

    2011-01-01

    We present transport measurements on a strongly coupled graphene quantum dot in a perpendicular magnetic field. The device consists of an etched single-layer graphene flake with two narrow constrictions separating a 140 nm diameter island from source and drain graphene contacts. Lateral graphene gates are used to electrostatically tune the device. Measurements of Coulomb resonances, including constriction resonances and Coulomb diamonds prove the functionality of the graphene quantum dot with a charging energy of approximately 4.5 meV. We show the evolution of Coulomb resonances as a function of perpendicular magnetic field, which provides indications of the formation of the graphene specific 0th Landau level. Finally, we demonstrate that the complex pattern superimposing the quantum dot energy spectra is due to the formation of additional localized states with increasing magnetic field. PMID:21711781

  7. Transient particle acceleration in strongly magnetized neutron stars. II - Effects due to a dipole field geometry

    NASA Technical Reports Server (NTRS)

    Fatuzzo, Marco; Melia, Fulvio

    1991-01-01

    Sheared Alfven waves generated by nonradial crustal disturbances above the polar cap of a strongly magnetized neutron star induce an electric field component parallel to B. An attempt is made to determine the manner in which the strong radial dependence of B affects the propagation of these sheared Alfven waves, and whether this MHD process is still an effective particle accelerator. It is found that although the general field equation is quite complicated, a simple wavelike solution can still be obtained under the conditions of interest for which the Alfven phase velocity decouples from the wave equation. The results may be applicable to gamma-ray burst sources.

  8. Effects of Strong Static Magnetic Fields on Amphibian Development and Gene Expression

    NASA Astrophysics Data System (ADS)

    Kawakami, Satomi; Kashiwagi, Keiko; Furuno, Nobuaki; Yamashita, Masamichi; Kashiwagi, Akihiko; Tanimoto, Yoshifumi

    2006-07-01

    This investigation attempts to clarify the effects of strong vertical and static magnetic fields (SMFs) of 11-15 T on Xenopus laevis development and on Xotx2 (an important regulator of fore- and midbrain morphogenesis) and Xag1 (essential for cement gland formation) gene expression. Results showed that (1) a strong SMF significantly retarded normal development and induced microcephaly, two heads, abnormal cement glands and multiple malformations, indicating that SMF inhibits normal embryonic development, (2) a strong SMF suppressed Xotx2 and Xag1 expression.

  9. Measurements of Heme Relaxation and Ligand Recombination in Strong Magnetic Fields

    PubMed Central

    Zhang, Zhenyu; Benabbas, Abdelkrim; Ye, Xiong; Yu, Anchi; Champion, Paul M.

    2009-01-01

    Heme cooling signals and diatomic ligand recombination kinetics are measured in strong magnetic fields (up to 10 Tesla). We examined diatomic ligand recombination to heme model compounds (NO and CO), myoglobin (NO and O2), and horseradish peroxidase (NO). No magnetic field induced rate changes in any of the samples were observed within the experimental detection limit. However, in the case of CO binding to heme in glycerol and O2 binding to myoglobin, we observe a small magnetic field dependent change in the early time amplitude of the optical response that is assigned to heme cooling. One possibility, consistent with this observation, is that there is a weak magnetic field dependence of the non-radiative branching ratio into the vibrationally hot electronic ground state during CO photolysis. Ancillary studies of the “spin-forbidden” CO binding reaction in a variety of heme compounds in the absence of magnetic field demonstrate a surprisingly wide range for the Arrhenius prefactor. We conclude that CO binding to heme is not always retarded by unfavorable spin selection rules involving a double spin-flip superexchange mechanism. In fact, it appears that the small prefactor (~109s−1) found for CO rebinding to Mb may be anomalous, rather than the general rule for heme-CO rebinding. These results point to unresolved fundamental issues that underlie the theory of heme-ligand photolysis and rebinding. PMID:19588986

  10. Measurements of heme relaxation and ligand recombination in strong magnetic fields.

    PubMed

    Zhang, Zhenyu; Benabbas, Abdelkrim; Ye, Xiong; Yu, Anchi; Champion, Paul M

    2009-08-06

    Heme cooling signals and diatomic ligand recombination kinetics are measured in strong magnetic fields (up to 10 T). We examined diatomic ligand recombination to heme model compounds (NO and CO), myoglobin (NO and O(2)), and horseradish peroxidase (NO). No magnetic field induced rate changes in any of the samples were observed within the experimental detection limit. However, in the case of CO binding to heme in glycerol and O(2) binding to myoglobin, we observe a small magnetic field dependent change in the early time amplitude of the optical response that is assigned to heme cooling. One possibility, consistent with this observation, is that there is a weak magnetic field dependence of the nonradiative branching ratio into the vibrationally hot electronic ground state during CO photolysis. Ancillary studies of the "spin-forbidden" CO binding reaction in a variety of heme compounds in the absence of magnetic field demonstrate a surprisingly wide range for the Arrhenius prefactor. We conclude that CO binding to heme is not always retarded by unfavorable spin selection rules involving a double spin-flip superexchange mechanism. In fact, it appears that the small prefactor ( approximately 10(9) s(-1)) found for CO rebinding to Mb may be anomalous, rather than the general rule for heme-CO rebinding. These results point to unresolved fundamental issues that underlie the theory of heme-ligand photolysis and rebinding.

  11. Optical visualisation of the flow around a cylinder in electrolyte under strong axial magnetic field.

    NASA Astrophysics Data System (ADS)

    Andreev, O.; Kobzev, A.; Kolesnikov, Yu.; Thess, A.

    Flows around obstacles are among the most common problems encountered in the fluid mechanics literature, and cylindrical obstacles definitely received the most extensive attention. The reason for this is that this relatively simple geometry already encompasses most of the important physical effects likely to play a role in flow around more complicated obstacles. This means that understanding the cylinder problem provides relevant insight on a wide variety of problem ranging from aerodynamics, with the flow around a wing or a vehicle, to pollutant dispersion around building, flows in turbines … When the working fluid conducts electricity additional effects are involved. In particular, the presence of a magnetic field tends to homogenise the flow in the direction of the magnetic field lines which leads to strong alterations of the flow patterns known from the classical nonconducting case. This configuration is also a very generic one as Magnetohydrodynamic flows around obstacle also occur in a wide variety of applications: for instance, the space vehicle re-entry problem features the flow of a conducting plasma around an obstacle: [1] and [2] have shown that it could be influenced by a strong magnetic field in order to reduce heat transfer. The cooling blanket of the future nuclear fusion reactor ITER soon to be built in France, features a complex flow of liquid metal in a very high magnetic field (typically 10 T), in which the occurrence of obstacles cannot be avoided.

  12. Relativistic electron motion in cylindrical waveguide with strong guiding magnetic field and high power microwave

    SciTech Connect

    Wu, Ping; Sun, Jun; Cao, Yibing

    2015-06-15

    In O-type high power microwave (HPM) devices, the annular relativistic electron beam is constrained by a strong guiding magnetic field and propagates through an interaction region to generate HPM. Some papers believe that the E × B drift of electrons may lead to beam breakup. This paper simplifies the interaction region with a smooth cylindrical waveguide to research the radial motion of electrons under conditions of strong guiding magnetic field and TM{sub 01} mode HPM. The single-particle trajectory shows that the radial electron motion presents the characteristic of radial guiding-center drift carrying cyclotron motion. The radial guiding-center drift is spatially periodic and is dominated by the polarization drift, not the E × B drift. Furthermore, the self fields of the beam space charge can provide a radial force which may pull electrons outward to some extent but will not affect the radial polarization drift. Despite the radial drift, the strong guiding magnetic field limits the drift amplitude to a small value and prevents beam breakup from happening due to this cause.

  13. Magnetic Fields in the Massive Dense Cores of the DR21 Filament: Weakly Magnetized Cores in a Strongly Magnetized Filament

    NASA Astrophysics Data System (ADS)

    Ching, Tao-Chung; Lai, Shih-Ping; Zhang, Qizhou; Girart, Josep M.; Qiu, Keping; Liu, Hauyu B.

    2017-04-01

    We present Submillimeter Array 880 μm dust polarization observations of six massive dense cores in the DR21 filament. The dust polarization shows complex magnetic field structures in the massive dense cores with sizes of 0.1 pc, in contrast to the ordered magnetic fields of the parsec-scale filament. The major axes of the massive dense cores appear to be aligned either parallel or perpendicular to the magnetic fields of the filament, indicating that the parsec-scale magnetic fields play an important role in the formation of the massive dense cores. However, the correlation between the major axes of the cores and the magnetic fields of the cores is less significant, suggesting that during the core formation, the magnetic fields below 0.1 pc scales become less important than the magnetic fields above 0.1 pc scales in supporting a core against gravity. Our analysis of the angular dispersion functions of the observed polarization segments yields a plane-of-sky magnetic field strength of 0.4–1.7 mG for the massive dense cores. We estimate the kinematic, magnetic, and gravitational virial parameters of the filament and the cores. The virial parameters show that the gravitational energy in the filament dominates magnetic and kinematic energies, while the kinematic energy dominates in the cores. Our work suggests that although magnetic fields may play an important role in a collapsing filament, the kinematics arising from gravitational collapse must become more important than magnetic fields during the evolution from filaments to massive dense cores.

  14. A strong magnetic field around the supermassive black hole at the centre of the Galaxy.

    PubMed

    Eatough, R P; Falcke, H; Karuppusamy, R; Lee, K J; Champion, D J; Keane, E F; Desvignes, G; Schnitzeler, D H F M; Spitler, L G; Kramer, M; Klein, B; Bassa, C; Bower, G C; Brunthaler, A; Cognard, I; Deller, A T; Demorest, P B; Freire, P C C; Kraus, A; Lyne, A G; Noutsos, A; Stappers, B; Wex, N

    2013-09-19

    Earth's nearest candidate supermassive black hole lies at the centre of the Milky Way. Its electromagnetic emission is thought to be powered by radiatively inefficient accretion of gas from its environment, which is a standard mode of energy supply for most galactic nuclei. X-ray measurements have already resolved a tenuous hot gas component from which the black hole can be fed. The magnetization of the gas, however, which is a crucial parameter determining the structure of the accretion flow, remains unknown. Strong magnetic fields can influence the dynamics of accretion, remove angular momentum from the infalling gas, expel matter through relativistic jets and lead to synchrotron emission such as that previously observed. Here we report multi-frequency radio measurements of a newly discovered pulsar close to the Galactic Centre and show that the pulsar's unusually large Faraday rotation (the rotation of the plane of polarization of the emission in the presence of an external magnetic field) indicates that there is a dynamically important magnetic field near the black hole. If this field is accreted down to the event horizon it provides enough magnetic flux to explain the observed emission--from radio to X-ray wavelengths--from the black hole.

  15. Effect of the {delta} meson on the instabilities of nuclear matter under strong magnetic fields

    SciTech Connect

    Rabhi, A.; Providencia, C.; Da Providencia, J.

    2009-08-15

    We study the influence of the isovector-scalar meson on the spinodal instabilities and the distillation effect in asymmetric nonhomogenous nuclear matter under strong magnetic fields of the order of 10{sup 18}-10{sup 19} G. Relativistic nuclear models both with constant couplings (NLW) and with density-dependent parameters (DDRH) are considered. A strong magnetic field can have large effects on the instability regions giving rise to bands of instability and wider unstable regions. It is shown that for neutron-rich matter the inclusion of the {delta} meson increases the size of the instability region for NLW models and decreases it for the DDRH models. The effect of the {delta} meson on the transition density to homogeneous {beta}-equilibrium matter is discussed. The DDRH{delta} model predicts the smallest transition pressures, about half the values obtained for NL{delta}.

  16. Observation of Bose-Einstein condensation in a strong synthetic magnetic field

    NASA Astrophysics Data System (ADS)

    Kennedy, Colin J.; Burton, William Cody; Chung, Woo Chang; Ketterle, Wolfgang

    2015-10-01

    Extensions of Berry’s phase and the quantum Hall effect have led to the discovery of new states of matter with topological properties. Traditionally, this has been achieved using magnetic fields or spin-orbit interactions, which couple only to charged particles. For neutral ultracold atoms, synthetic magnetic fields have been created that are strong enough to realize the Harper-Hofstadter model. We report the first observation of Bose-Einstein condensation in this system and study the Harper-Hofstadter Hamiltonian with one-half flux quantum per lattice unit cell. The diffraction pattern of the superfluid state directly shows the momentum distribution of the wavefunction, which is gauge-dependent. It reveals both the reduced symmetry of the vector potential and the twofold degeneracy of the ground state. We explore an adiabatic many-body state preparation protocol via the Mott insulating phase and observe the superfluid ground state in a three-dimensional lattice with strong interactions.

  17. The study of relatively low density stellar matter in presence of strong quantizing magnetic field

    SciTech Connect

    Nag, Nandini; Ghosh, Sutapa; Chakrabarty, Somenath

    2009-03-15

    The effect of strong quantizing magnetic field on the equation of state of matter at the outer crust region of magnetars is studied. The density of such matter is low enough compared to the matter density at the inner crust or outer core region. Based on the relativistic version of semi-classical Thomas-Fermi-Dirac model in presence of strong quantizing magnetic field a formalism is developed to investigate this specific problem. The equation of state of such low density crustal matter is obtained by replacing the compressed atoms/ions by Wigner-Seitz cells with nonuniform electron density. The results are compared with other possible scenarios. The appearance of Thomas-Fermi induced electric charge within each Wigner-Seitz cell is also discussed.

  18. Quark matter with strong magnetic field and possibility of the third family of compact stars

    NASA Astrophysics Data System (ADS)

    Sotani, Hajime; Tatsumi, Toshitaka

    2017-05-01

    We consider the possibility for the existence of the third family of compact objects, considering the effect of strong magnetic fields inside the hybrid stars. As a result, we demonstrate such new sequences of stable equilibrium configurations for some hadronic equations of state. Through the analysis of the adiabatic index inside stars, we find the conditions for appearing the third family of compact objects, i.e. for hadronic stars without quarks, that the maximum mass should be small, the central density for the maximum mass should be also small, and the radius for the maximum mass should be large. Even for soft hadronic equations of state, the two solar-mass stars might survive as the third family of compact objects, once quark matter with strong magnetic field, such as {˜ } O(10^{19} G), is taken into account. It might give a hint to solve the so-called hyperon puzzle in nuclear physics.

  19. He2+ molecular ion and the He- atomic ion in strong magnetic fields

    NASA Astrophysics Data System (ADS)

    Vieyra, J. C. Lopez; Turbiner, A. V.

    2017-08-01

    We study the question of existence, i.e., stability with respect to dissociation of the spin-quartet permutation- and reflection-symmetric 4(-3) +g (Sz=-3 /2 ,M =-3 ) state of the (α α e e e ) Coulomb system: the He2 + molecular ion, placed in a magnetic field 0 ≤B ≤10 000 a.u. We assume that the α particles are infinitely massive (Born-Oppenheimer approximation of zero order) and adopt the parallel configuration, when the molecular axis and the magnetic field direction coincide, as the optimal configuration. The study of the stability is performed variationally with a physically adequate trial function. To achieve this goal, we explore several helium-containing compounds in strong magnetic fields, in particular; we study the spin-quartet ground state of the He- ion and the ground (spin-triplet) state of the helium atom, both for a magnetic field in 100 ≤B ≤10 000 a.u. The main result is that the He2 + molecular ion in the state 4(-3) +g is stable towards all possible decay modes for magnetic fields B ≳120 a .u . and with the magnetic field increase the ion becomes more tightly bound and compact with a cigar-type form of electronic cloud. At B =1000 a .u . , the dissociation energy of He2 + into He-+α is ˜702 eV and the dissociation energy for the decay channel to He +α +e is ˜729 eV , and both energies are in the energy window for one of the observed absorption features of the isolated neutron star 1E1207.4-5209.

  20. Comptonization in Ultra-Strong Magnetic Fields: Numerical Solution to the Radiative Transfer Problem

    NASA Technical Reports Server (NTRS)

    Ceccobello, C.; Farinelli, R.; Titarchuk, L.

    2014-01-01

    We consider the radiative transfer problem in a plane-parallel slab of thermal electrons in the presence of an ultra-strong magnetic field (B approximately greater than B(sub c) approx. = 4.4 x 10(exp 13) G). Under these conditions, the magnetic field behaves like a birefringent medium for the propagating photons, and the electromagnetic radiation is split into two polarization modes, ordinary and extraordinary, that have different cross-sections. When the optical depth of the slab is large, the ordinary-mode photons are strongly Comptonized and the photon field is dominated by an isotropic component. Aims. The radiative transfer problem in strong magnetic fields presents many mathematical issues and analytical or numerical solutions can be obtained only under some given approximations. We investigate this problem both from the analytical and numerical point of view, provide a test of the previous analytical estimates, and extend these results with numerical techniques. Methods. We consider here the case of low temperature black-body photons propagating in a sub-relativistic temperature plasma, which allows us to deal with a semi-Fokker-Planck approximation of the radiative transfer equation. The problem can then be treated with the variable separation method, and we use a numerical technique to find solutions to the eigenvalue problem in the case of a singular kernel of the space operator. The singularity of the space kernel is the result of the strong angular dependence of the electron cross-section in the presence of a strong magnetic field. Results. We provide the numerical solution obtained for eigenvalues and eigenfunctions of the space operator, and the emerging Comptonization spectrum of the ordinary-mode photons for any eigenvalue of the space equation and for energies significantly lesser than the cyclotron energy, which is on the order of MeV for the intensity of the magnetic field here considered. Conclusions. We derived the specific intensity of the

  1. Implications of strong intergalactic magnetic fields for ultrahigh-energy cosmic-ray astronomy

    NASA Astrophysics Data System (ADS)

    Alves Batista, Rafael; Shin, Min-Su; Devriendt, Julien; Semikoz, Dmitri; Sigl, Guenter

    2017-07-01

    We study the propagation of ultrahigh-energy cosmic rays in the magnetized cosmic web. We focus on the particular case of highly magnetized voids (B ˜nG ), using the upper bounds from the Planck satellite. The cosmic web was obtained from purely magnetohydrodynamical cosmological simulations of structure formation considering different power spectra for the seed magnetic field in order to account for theoretical uncertainties. We investigate the impact of these uncertainties on the propagation of cosmic rays, showing that they can affect the measured spectrum and composition by up to ≃80 % and ≃5 %, respectively. In our scenarios, even if magnetic fields in voids are strong, deflections of 50 EeV protons from sources closer than ˜50 Mpc are less than 15° in approximately 10-50% of the sky, depending on the distribution of sources and magnetic power spectrum. Therefore, UHECR astronomy might be possible in a significant portion of the sky depending on the primordial magnetic power spectrum, provided that protons constitute a sizeable fraction of the observed UHECR flux.

  2. High-spatial-resolution monitoring of strong magnetic field using Rb vapor nanometric-thin cell

    NASA Astrophysics Data System (ADS)

    Hakhumyan, G.; Leroy, C.; Pashayan-Leroy, Y.; Sarkisyan, D.; Auzinsh, M.

    2011-08-01

    We have implemented the so-called λ-Zeeman technique (LZT) to investigate individual hyperfine transitions between Zeeman sublevels of the Rb atoms in a strong external magnetic field B in the range of 2500 - 5000 G (recently it was established that LZT is very convenient for the range of 10 - 2500 G). Atoms are confined in a nanometric thin cell (NTC) with the thickness L = λ, where λ is the resonant wavelength 794 nm for Rb D 1 line. Narrow velocity selective optical pumping (VSOP) resonances in the transmission spectrum of the NTC are split into several components in a magnetic field with the frequency positions and transition probabilities depending on the B-field. Possible applications are described, such as magnetometers with nanometric local spatial resolution and tunable atomic frequency references.

  3. Study of Fluid Flow Control in Protein Crystallization using Strong Magnetic Fields

    NASA Technical Reports Server (NTRS)

    Ramachandran, Narayanan; Leslie, Fred; Ciszak, Ewa

    2002-01-01

    An important component in biotechnology, particularly in the area of protein engineering and rational drug design is the knowledge of the precise three-dimensional molecular structure of proteins. The quality of structural information obtained from X-ray diffraction methods is directly dependent on the degree of perfection of the protein crystals. As a consequence, the growth of high quality macromolecular crystals for diffraction analyses has been the central focus for biochemists, biologists, and bioengineers. Macromolecular crystals are obtained from solutions that contain the crystallizing species in equilibrium with higher aggregates, ions, precipitants, other possible phases of the protein, foreign particles, the walls of the container, and a likely host of other impurities. By changing transport modes in general, i.e., reduction of convection and sedimentation, as is achieved in "microgravity", researchers have been able to dramatically affect the movement and distribution of macromolecules in the fluid, and thus their transport, formation of crystal nuclei, and adsorption to the crystal surface. While a limited number of high quality crystals from space flights have been obtained, as the recent National Research Council (NRC) review of the NASA microgravity crystallization program pointed out, the scientific approach and research in crystallization of proteins has been mainly empirical yielding inconclusive results. We postulate that we can reduce convection in ground-based experiments and we can understand the different aspects of convection control through the use of strong magnetic fields and field gradients. Whether this limited convection in a magnetic field will provide the environment for the growth of high quality crystals is still a matter of conjecture that our research will address. The approach exploits the variation of fluid magnetic susceptibility with concentration for this purpose and the convective damping is realized by appropriately

  4. Cold equation of state in a strong magnetic field - Effects of inverse beta-decay

    NASA Technical Reports Server (NTRS)

    Lai, Dong; Shapiro, Stuart L.

    1991-01-01

    The influence of a high magnetic field (B is greater than 10 exp 12 G) on the degenerate matter equation of state appropriate to a neutron star is studied. The regime dominated by relativistic electrons up to the neutron drip density is highlighted. The equilibrium matter composition and equation of state, allowing for inverse beta-decay. Two different equilibrium models are determined: an ideal neutron-proton-electron (npe) gas and the more realistic model of Baym, Pethick, and Sutherland (1971) consisting of a Coulomb lattice of heavy nuclei embedded in an electron gas. For a sufficiently high field strength, the magnetic field has an appreciable effect, changing the adiabatic index of the matter and the nuclear transition densities. The influence of a strong field on some simple nonequilibrium processes, including beta-decay and inverse beta-decay (electron capture) is also considered. The effects produced by the magnetic field are mainly due to the changes in the transverse electron quantum orbits and the allowed electron phase space induced by the field.

  5. Generation of strong pulsed magnetic fields using a compact, short pulse generator

    SciTech Connect

    Yanuka, D.; Efimov, S.; Nitishinskiy, M.; Rososhek, A.; Krasik, Ya. E.

    2016-04-14

    The generation of strong magnetic fields (∼50 T) using single- or multi-turn coils immersed in water was studied. A pulse generator with stored energy of ∼3.6 kJ, discharge current amplitude of ∼220 kA, and rise time of ∼1.5 μs was used in these experiments. Using the advantage of water that it has a large Verdet constant, the magnetic field was measured using the non-disturbing method of Faraday rotation of a polarized collimated laser beam. This approach does not require the use of magnetic probes, which are sensitive to electromagnetic noise and damaged in each shot. It also avoids the possible formation of plasma by either a flashover along the conductor or gas breakdown inside the coil caused by an induced electric field. In addition, it was shown that this approach can be used successfully to investigate the interesting phenomenon of magnetic field enhanced diffusion into a conductor.

  6. Generation of strong pulsed magnetic fields using a compact, short pulse generator

    NASA Astrophysics Data System (ADS)

    Yanuka, D.; Efimov, S.; Nitishinskiy, M.; Rososhek, A.; Krasik, Ya. E.

    2016-04-01

    The generation of strong magnetic fields (˜50 T) using single- or multi-turn coils immersed in water was studied. A pulse generator with stored energy of ˜3.6 kJ, discharge current amplitude of ˜220 kA, and rise time of ˜1.5 μs was used in these experiments. Using the advantage of water that it has a large Verdet constant, the magnetic field was measured using the non-disturbing method of Faraday rotation of a polarized collimated laser beam. This approach does not require the use of magnetic probes, which are sensitive to electromagnetic noise and damaged in each shot. It also avoids the possible formation of plasma by either a flashover along the conductor or gas breakdown inside the coil caused by an induced electric field. In addition, it was shown that this approach can be used successfully to investigate the interesting phenomenon of magnetic field enhanced diffusion into a conductor.

  7. Active galaxies. A strong magnetic field in the jet base of a supermassive black hole.

    PubMed

    Martí-Vidal, Ivan; Muller, Sébastien; Vlemmings, Wouter; Horellou, Cathy; Aalto, Susanne

    2015-04-17

    Active galactic nuclei (AGN) host some of the most energetic phenomena in the universe. AGN are thought to be powered by accretion of matter onto a rotating disk that surrounds a supermassive black hole. Jet streams can be boosted in energy near the event horizon of the black hole and then flow outward along the rotation axis of the disk. The mechanism that forms such a jet and guides it over scales from a few light-days up to millions of light-years remains uncertain, but magnetic fields are thought to play a critical role. Using the Atacama Large Millimeter/submillimeter Array (ALMA), we have detected a polarization signal (Faraday rotation) related to the strong magnetic field at the jet base of a distant AGN, PKS 1830-211. The amount of Faraday rotation (rotation measure) is proportional to the integral of the magnetic field strength along the line of sight times the density of electrons. The high rotation measures derived suggest magnetic fields of at least tens of Gauss (and possibly considerably higher) on scales of the order of light-days (0.01 parsec) from the black hole.

  8. Production of large volume, strongly magnetized laser-produced plasmas by use of pulsed external magnetic fields

    SciTech Connect

    Albertazzi, B.; Beard, J.; Billette, J.; Portugall, O.; Ciardi, A.; Vinci, T.; Albrecht, J.; Chen, S. N.; Da Silva, D.; Hirardin, B.; Nakatsutsumi, M.; Romagnagni, L.; Simond, S.; Veuillot, E.; Fuchs, J.; Burris-Mog, T.; Dittrich, S.; Herrmannsdoerfer, T.; Kroll, F.; Nitsche, S.; and others

    2013-04-15

    The production of strongly magnetized laser plasmas, of interest for laboratory astrophysics and inertial confinement fusion studies, is presented. This is achieved by coupling a 16 kV pulse-power system. This is achieved by coupling a 16 kV pulse-power system, which generates a magnetic field by means of a split coil, with the ELFIE laser facility at Ecole Polytechnique. In order to influence the plasma dynamics in a significant manner, the system can generate, repetitively and without debris, high amplitude magnetic fields (40 T) in a manner compatible with a high-energy laser environment. A description of the system and preliminary results demonstrating the possibility to magnetically collimate plasma jets are given.

  9. Mean field analysis of the high temperature magnetic properties of terbium iron garnet in strong DC fields

    NASA Astrophysics Data System (ADS)

    Lahoubi, Mahieddine; Wang, Wei

    2015-11-01

    This paper is devoted to the description of the magnetic phase diagrams (MPD) together with a special interest to the determination of more precise values of some reliable parameters at the compensation point, Tcomp=243.5±0.5 K of the terbium iron garnet, Tb3Fe5O12 or TbIG. Using isothermal magnetizations performed on single crystal in strong DC magnetic fields up to 200 kOe applied along the <111>, <110> and <100> directions within the temperature range 128-295 K, field-induced phase transitions between collinear and canted phases are observed in the vicinity of Tcomp at critical fields, Hc2. In comparison with the measurement at zero external magnetic field, the specific heat, Cp(T) at 80 kOe along <111> shows an excess around Tcomp characterized by an anomaly which has a width in the boundaries of the canted phase and a maximum at 252 K, the more accurate value of the critical temperature, TC* of the MPD in the (Hc2-T) plane. Better determinations of the molecular field coefficients which represent the magnetic interactions on the Tb sublattice are obtained by an improved molecular field model based on the saturation effects of the Tb sublattice and the differential susceptibility contribution due to the Fe sublattices to the total magnetic susceptibility of TbIG. The results are discussed in terms of the previous theoretical studies of the MPD predicted for weakly anisotropic ferrimagnets.

  10. Spin superconductivity and ac-Josephson effect in Graphene system under strong magnetic field

    NASA Astrophysics Data System (ADS)

    Liu, Haiwen; Jiang, Hua; Sun, Qing-Feng; Xie, X. C.; Collaborative Innovation Center of Quantum Matter, Beijing, China Collaboration

    We study the spin superconductivity in Graphene system under strong magnetic field. From the microscopically Gor'kov method combined with the Aharonov-Casher effect, we derive the effective Landau-Ginzburg free energy and analyze the time evolution of order parameter, which is confirmed to be the off-diagonal long range order. Meanwhile, we compare the ground state of spin superconductivity to the canted-antiferromagnetic state, and demonstrate the equivalence between these two states. Moreover, we give out the pseudo-field flux quantization condition of spin supercurrent, and propose an experimental measurable ac-Josephson effect of spin superconductivity in this system.

  11. Integrated electronic transport and thermometry at milliKelvin temperatures and in strong magnetic fields.

    PubMed

    Samkharadze, N; Kumar, A; Manfra, M J; Pfeiffer, L N; West, K W; Csáthy, G A

    2011-05-01

    We fabricated a He-3 immersion cell for transport measurements of semiconductor nanostructures at ultra low temperatures and in strong magnetic fields. We have a new scheme of field-independent thermometry based on quartz tuning fork Helium-3 viscometry which monitors the local temperature of the sample's environment in real time. The operation and measurement circuitry of the quartz viscometer is described in detail. We provide evidence that the temperature of two-dimensional electron gas confined to a GaAs quantum well follows the temperature of the quartz viscometer down to 4 mK.

  12. Integrated electronic transport and thermometry at milliKelvin temperatures and in strong magnetic fields

    SciTech Connect

    Samkharadze, N.; Kumar, A.; Csathy, G. A.; Manfra, M. J.; Pfeiffer, L. N.; West, K. W.

    2011-05-15

    We fabricated a He-3 immersion cell for transport measurements of semiconductor nanostructures at ultra low temperatures and in strong magnetic fields. We have a new scheme of field-independent thermometry based on quartz tuning fork Helium-3 viscometry which monitors the local temperature of the sample's environment in real time. The operation and measurement circuitry of the quartz viscometer is described in detail. We provide evidence that the temperature of two-dimensional electron gas confined to a GaAs quantum well follows the temperature of the quartz viscometer down to 4 mK.

  13. Influence of a strong magnetic field on paramagnetic fluid's flow in cubical enclosure

    NASA Astrophysics Data System (ADS)

    Kraszewska, A.; Pyrda, L.; Donizak, J.

    2016-10-01

    The fluid behaviour in thermo-magnetic convection of paramagnetic fluid in a strong magnetic field was studied. The fluid was 50% volume aqueous solution of glycerol with an addition of gadolinium nitrate hexahydrate (Gd(NO3)3-6H2O). Experimental enclosure - a vessel with aspect ratio (AR=height/width) equal to 1.0 - was heated from the bottom, and cooled from the top. Temperature difference between top and bottom walls was kept constant at ΔT = 5 and 11 [°C]. The magnetic induction was increased stepwise from 1 to 10 [T] and thermocouples placed inside the enclosures measured temperature changes of the fluid. On the basis of temperature measurements, analysis of the fluid flow was performed.

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

    SciTech Connect

    Kelner, S. R.; Prosekin, A. Yu.; Aharonian, F. A. E-mail: Anton.Prosekin@mpi-hd.mpg.de

    2015-01-01

    It is generally believed that the radiation of relativistic particles in a curved magnetic field proceeds in either the synchrotron or the curvature radiation modes. In this paper we show that in strong curved magnetic fields a significant fraction of the energy of relativistic electrons can be radiated away in the intermediate, the so-called synchro-curvature regime. Because of the persistent change of the trajectory curvature, the radiation varies with the frequency of particle gyration. While this effect can be ignored in the synchrotron and curvature regimes, the variability plays a key role in the formation of the synchro-curvature radiation. Using the Hamiltonian formalism, we find that the particle trajectory has the form of a helix wound around the drift trajectory. This allows us to calculate analytically the intensity and energy distribution of prompt radiation in the general case of magnetic bremsstrahlung in the curved magnetic field. We show that the transition to the limit of the synchrotron and curvature radiation regimes is determined by the relation between the drift velocity and the component of the particle velocity perpendicular to the drift trajectory. The detailed numerical calculations, which take into account the energy losses of particles, confirm the principal conclusions based on the simplified analytical treatment of the problem, and allow us to analyze quantitatively the transition between different radiation regimes for a broad range of initial pitch angles. These calculations demonstrate that even very small pitch angles may lead to significant deviations from the spectrum of the standard curvature radiation when it is formally assumed that a charged particle moves strictly along the magnetic line. We argue that in the case of realization of specific configurations of the electric and magnetic fields, the gamma-ray emission of the pulsar magnetospheres can be dominated by the component radiated in the synchro-curvature regime.

  15. Plasma kinetic processes in a strong d.c. magnetic field

    NASA Technical Reports Server (NTRS)

    Montgomery, D.

    1976-01-01

    Recent results in the kinetic theory of a strongly magnetized plasma are surveyed. Emphasis is on the electrostatic guiding-center plasma in two dimensions, in both the fluid and 'charged rod' descriptions. The basic kinetic description of the plasma is in terms of the statistically-distributed Fourier coefficients associated with the velocity and 'enstrophy' (charge density) fields. It is a universal tendency in such media for enstrophy to flow to shorter wavelengths but for energy to flow to longer wavelengths. A consequence of the energy flow to longer wavelengths is the generation of long-range order in the form of macroscopic vortices. These kinds of structure have been called 'convection cells' and can be extraordinarily efficient in transporting particles transverse to a magnetic field. The tendency to vortex formation can be disrupted by collisions between particles. Modifications of the Fokker-Planck equation for a plasma produced by a strong dc magnetic field are considered in both two and three dimensions.

  16. Bending of electromagnetic wave in an ultra-strong magnetic field

    SciTech Connect

    Kim, Jin Young

    2012-10-01

    We consider the bending of light by nonlinear electrodynamics when the magnetic field B exceeds the critical value B{sub c} = m{sup 2}c{sup 2}/e h-bar = 4.4 × 10{sup 9}T. Using the index of refraction derived from the analytic series representation in one-loop effective action of QED, we found the trajectory and the bending angle of light in geometric optics. The angle bent by ultra-strong magnetic field of magnetar was estimated and compared with the gravitational bending. The result may be useful in studying the lensing, birefringence, and other nonlinear quantum electrodynamic effects above B{sub c}.

  17. Instanton paths and coherent quantum tunneling in antiferromagnetic spin clusters subject to a strong magnetic field

    SciTech Connect

    Ivanov, B. A. Kireev, V. E.

    2008-09-15

    The coherent quantum tunneling effects in antiferromagnets in the presence of a strong external magnetic field parallel to the easy axis have been investigated using the instanton formalism. In a wide field range including the region of the phase spin-flop transition, the tunneling is described by 180{sup o} instantons for which the Euclidean action is real and destructive interference is absent. At the transition point, 90{sup o} instantons describing the tunneling between the collinear and spin-flop states appear. The Euclidean action decreases, whereas the tunneling probability and tunneling level splitting in both phases increase significantly in the immediate vicinity of the spin-flop transition point. The possibility of observing the coherent tunneling effects for artificial small particles (magnetic dots) made of antiferromagnets is discussed.

  18. Turbulent convection in a horizontal duct with strong axial magnetic field

    NASA Astrophysics Data System (ADS)

    Zhang, Xuan; Zikanov, Oleg

    2014-11-01

    Convection in a horizontal duct with one heated wall is studied computationally. The work is motivated by the concept of a blanket for fusion reactors, according to which liquid metal slowly flows in toroidal ducts aligned with the main component of the magnetic field. We first assume that the magnetic field is sufficiently strong for the flow to be purely two-dimensional and analyze chaotic flow regimes at very high Grashof numbers. Furthermore, three-dimensional perturbations are considered and the relation between the length of the duct and the critical Hartmann number, below which the flow becomes three-dimensional, is determined. Financial support was provided by the US NSF (Grant CBET 1232851).

  19. Quasiparticles of strongly correlated Fermi liquids at high temperatures and in high magnetic fields

    NASA Astrophysics Data System (ADS)

    Shaginyan, V. R.

    2011-08-01

    Strongly correlated Fermi systems are among the most intriguing, best experimentally studied and fundamental systems in physics. There is, however, lack of theoretical understanding in this field of physics. The ideas based on the concepts like Kondo lattice and involving quantum and thermal fluctuations at a quantum critical point have been used to explain the unusual physics. Alas, being suggested to describe one property, these approaches fail to explain the others. This means a real crisis in theory suggesting that there is a hidden fundamental law of nature. It turns out that the hidden fundamental law is well forgotten old one directly related to the Landau-Migdal quasiparticles, while the basic properties and the scaling behavior of the strongly correlated systems can be described within the framework of the fermion condensation quantum phase transition (FCQPT). The phase transition comprises the extended quasiparticle paradigm that allows us to explain the non-Fermi liquid (NFL) behavior observed in these systems. In contrast to the Landau paradigm stating that the quasiparticle effective mass is a constant, the effective mass of new quasiparticles strongly depends on temperature, magnetic field, pressure, and other parameters. Our observations are in good agreement with experimental facts and show that FCQPT is responsible for the observed NFL behavior and quasiparticles survive both high temperatures and high magnetic fields.

  20. Quasiparticles of strongly correlated Fermi liquids at high temperatures and in high magnetic fields

    SciTech Connect

    Shaginyan, V. R.

    2011-08-15

    Strongly correlated Fermi systems are among the most intriguing, best experimentally studied and fundamental systems in physics. There is, however, lack of theoretical understanding in this field of physics. The ideas based on the concepts like Kondo lattice and involving quantum and thermal fluctuations at a quantum critical point have been used to explain the unusual physics. Alas, being suggested to describe one property, these approaches fail to explain the others. This means a real crisis in theory suggesting that there is a hidden fundamental law of nature. It turns out that the hidden fundamental law is well forgotten old one directly related to the Landau-Migdal quasiparticles, while the basic properties and the scaling behavior of the strongly correlated systems can be described within the framework of the fermion condensation quantum phase transition (FCQPT). The phase transition comprises the extended quasiparticle paradigm that allows us to explain the non-Fermi liquid (NFL) behavior observed in these systems. In contrast to the Landau paradigm stating that the quasiparticle effective mass is a constant, the effective mass of new quasiparticles strongly depends on temperature, magnetic field, pressure, and other parameters. Our observations are in good agreement with experimental facts and show that FCQPT is responsible for the observed NFL behavior and quasiparticles survive both high temperatures and high magnetic fields.

  1. High Power Laser-Plasma Interaction under a Strong Magnetic Field

    NASA Astrophysics Data System (ADS)

    Sano, Takayoshi; Tanaka, Yuki; Yamaguchi, Tomohito; Murakami, Masakatsu; Iwata, Natsumi; Hata, Masayasu; Mima, Kunioki

    2016-10-01

    We investigate laser-plasma interactions under a strong magnetic field by one-dimensional Particle-in-Cell (PIC) simulations. A simple setup is considered in our analysis, in which a thin foil is irradiated by a right-handed circularly polarized laser. A uniform magnetic field is assumed in the direction of the laser propagation. Then the whistler wave can penetrate the overdense plasma when the external field is larger than the critical field strength Bc =meω0 / e . In this situation, key parameters of the system are the plasma density and the size of the external field. We performed various models in the density-field strength diagram, which is actually the so-called CMA diagram, to evaluate the efficiency of the energy conversion from the laser to plasma and the reflectivity and transmittance of the laser. It is found that there are two important processes in the interaction between the whistler wave and overdense plasma, which are the cyclotron resonance of relativistic electrons and the parametric (Brillouin) instability. Because of the high temperature of electrons, ions can be accelerated dramatically by a large sheath field at the target surface.

  2. Electrostatic focal spot correction for x-ray tubes operating in strong magnetic fields.

    PubMed

    Lillaney, Prasheel; Shin, Mihye; Hinshaw, Waldo; Fahrig, Rebecca

    2014-11-01

    orthogonal field does not affect the electrostatic correction technique. However, rotation of the x-ray tube by 30° toward the MR bore increases the parallel magnetic field magnitude (∼72 mT). The presence of this larger parallel field along with the orthogonal field leads to incomplete correction. Monte Carlo simulations demonstrate that the mean energy of the x-ray spectrum is not noticeably affected by the electrostatic correction, but the output flux is reduced by 7.5%. The maximum orthogonal magnetic field magnitude that can be compensated for using the proposed design is 65 mT. Larger orthogonal field magnitudes cannot be completely compensated for because a pure electrostatic approach is limited by the dielectric strength of the vacuum inside the x-ray tube insert. The electrostatic approach also suffers from limitations when there are strong magnetic fields in both the orthogonal and parallel directions because the electrons prefer to stay aligned with the parallel magnetic field. These challenging field conditions can be addressed by using a hybrid correction approach that utilizes both active shielding coils and biasing electrodes.

  3. Electrostatic focal spot correction for x-ray tubes operating in strong magnetic fields

    PubMed Central

    Lillaney, Prasheel; Shin, Mihye; Hinshaw, Waldo; Fahrig, Rebecca

    2014-01-01

    field in addition to the orthogonal field does not affect the electrostatic correction technique. However, rotation of the x-ray tube by 30° toward the MR bore increases the parallel magnetic field magnitude (∼72 mT). The presence of this larger parallel field along with the orthogonal field leads to incomplete correction. Monte Carlo simulations demonstrate that the mean energy of the x-ray spectrum is not noticeably affected by the electrostatic correction, but the output flux is reduced by 7.5%. Conclusions: The maximum orthogonal magnetic field magnitude that can be compensated for using the proposed design is 65 mT. Larger orthogonal field magnitudes cannot be completely compensated for because a pure electrostatic approach is limited by the dielectric strength of the vacuum inside the x-ray tube insert. The electrostatic approach also suffers from limitations when there are strong magnetic fields in both the orthogonal and parallel directions because the electrons prefer to stay aligned with the parallel magnetic field. These challenging field conditions can be addressed by using a hybrid correction approach that utilizes both active shielding coils and biasing electrodes. PMID:25370658

  4. Generation of strong magnetic fields in hybrid and quark stars driven by the electroweak interaction of quarks

    NASA Astrophysics Data System (ADS)

    Dvornikov, Maxim

    2017-01-01

    We study the generation of strong large scale magnetic fields in compact stars containing degenerate quark matter with unbroken chiral symmetry. The magnetic field growth is owing to the magnetic field instability driven by the electroweak interaction of quarks. In this system we predict the enhancement of the seed magnetic field 1012 G to the strengths (1014 - 1015) G. In our analysis we use the typical parameters of the quark matter in the core of a hybrid star or in a quark star. We also apply of the obtained results to model the generation of magnetic fields in magnetars.

  5. Nonperturbative ab initio calculations in strong magnetic fields using London orbitals

    NASA Astrophysics Data System (ADS)

    Tellgren, Erik I.; Soncini, Alessandro; Helgaker, Trygve

    2008-10-01

    A self-consistent field (SCF) London-orbital computational scheme to perform gauge-origin independent nonperturbative calculations for molecules in strong magnetic fields is presented. The crucial difference in the proposed approach with respect to common-origin finite-field SCF implementations consists in the evaluation of molecular integrals over the field-dependent molecular basis functions, which is tantamount to computing molecular integrals in a hybrid Gaussian and plane-wave basis set. The implementation of a McMurchie-Davidson scheme for the calculation of the molecular integrals over London orbitals is discussed, and preliminary applications of the newly developed code to the calculation of fourth-rank hypermagnetizabilities for a set of small molecules, benzene, and cyclobutadiene are presented. The nonperturbative approach is particularly useful for studying the highly nonlinear response of paramagnetic closed-shell systems such as boron monohydride, or the π-electron response of cyclobutadiene.

  6. Transport features in laser-plasma-deposited InMnAs layers in strong magnetic fields

    SciTech Connect

    Rylkov, V. V. Aronzon, B. A.; Lagutin, A. S.; Podol'skii, V. V.; Lesnikov, V. P.; Goiran, M.; Galibert, J.; Raquet, B.; Leotin, J.

    2009-01-15

    We have studied the magnetotransport properties of p-InMnAs layers in strong (up to 30 T) pulsed magnetic fields. The p-InMnAs layers were obtained by laser plasma deposition with subsequent annealing by radiation of a pulsed ruby laser. Under anomalous Hall effect conditions in a strong magnetic field (above 20 T), the Hall resistance in the paramagnetic region of temperatures is greater than that in the ferromagnetic region (below 40 K). It has also been established that, at helium temperatures, the negative magnetoresistance exhibits saturation in a field of about 10 T, whereas the anomalous Hall effect is saturated at about 2 T. At T {approx} 4 K, the resistance in a field of 10 T exhibits a more than tenfold decrease. The results are explained by a mesoscopically inhomogeneous distribution of the acceptor (Mn) impurity, a local ferromagnetic transition, and a percolation character of the conductivity of p-InMnAs films in a state close to the insulator-metal phase transition. The characteristic scale of magnetoelectric inhomogeneity in the system is evaluated based on an analysis of mesoscopic fluctuations of the nondiagonal component of the magnetoresistance tensor.

  7. The Ground State of Monolayer Graphene in a Strong Magnetic Field

    PubMed Central

    Wu, Lian-Ao; Guidry, Mike

    2016-01-01

    Experiments indicate that the ground state of graphene in a strong magnetic field exhibits spontaneous breaking of SU(4) symmetry. However, the nature of the corresponding emergent state is unclear because existing theoretical methods approximate the broken-symmetry solutions, yielding nearly-degenerate candidate ground states having different emergent orders. Resolving this ambiguity in the nature of the strong-field ground state is highly desirable, given the importance of graphene for both fundamental physics and technical applications. We have discovered a new SO(8) symmetry that recovers standard graphene SU(4) quantum Hall physics, but predicts two new broken-SU(4) phases and new properties for potential ground states. Our solutions are analytical; thus we capture the essential physics of spontaneously-broken SU(4) states in a powerful yet solvable model useful both in correlating existing data and in suggesting new experiments. PMID:26927477

  8. Study of Fluid Flow Control In Protein Crystallization Using Strong Magnetic Fields

    NASA Technical Reports Server (NTRS)

    Ramachandran, N.; Leslie, F.; Ciszak, E.; Curreri, Peter A. (Technical Monitor)

    2002-01-01

    An important component in biotechnology, particularly in the area of protein engineering and rational drug design is the knowledge of the precise three-dimensional molecular structure of proteins. The quality of structural information obtained from X-ray diffraction methods is directly dependent on the degree of perfection of the protein crystals. As a consequence, the growth of high quality macromolecular crystals for diffraction analyses has been the central focus for biochemists, biologists, and bioengineers. Macromolecular crystals are obtained from solutions that contain the crystallizing species in equilibrium with higher aggregates, ions, precipitants, other possible phases of the protein, foreign particles, the walls of the container, and a likely host of other impurities. By changing transport modes in general, i.e., reduction of convection and sedimentation, as is achieved in 'microgravity', researchers have been able to dramatically affect the movement and distribution of macromolecules in the fluid, and thus their transport, formation of crystal nuclei, and adsorption to the crystal surface. While a limited number of high quality crystals from space flights have been obtained, as the recent National Research Council (NRC) review of the NASA microgravity crystallization program pointed out, the scientific approach and research in crystallization of proteins has been mainly empirical yielding inconclusive results. We postulate that we can reduce convection in ground-based experiments and we can understand the different aspects of convection control through the use of strong magnetic fields and field gradients. Whether this limited convection in a magnetic field will provide the environment for the growth of high quality crystals is still a matter of conjecture that our research will address. The approach exploits the variation of fluid magnetic susceptibility with concentration for this purpose and the convective damping is realized by appropriately

  9. Study of Fluid Flow Control In Protein Crystallization Using Strong Magnetic Fields

    NASA Technical Reports Server (NTRS)

    Ramachandran, N.; Leslie, F.; Ciszak, E.; Curreri, Peter A. (Technical Monitor)

    2002-01-01

    An important component in biotechnology, particularly in the area of protein engineering and rational drug design is the knowledge of the precise three-dimensional molecular structure of proteins. The quality of structural information obtained from X-ray diffraction methods is directly dependent on the degree of perfection of the protein crystals. As a consequence, the growth of high quality macromolecular crystals for diffraction analyses has been the central focus for biochemists, biologists, and bioengineers. Macromolecular crystals are obtained from solutions that contain the crystallizing species in equilibrium with higher aggregates, ions, precipitants, other possible phases of the protein, foreign particles, the walls of the container, and a likely host of other impurities. By changing transport modes in general, i.e., reduction of convection and sedimentation, as is achieved in 'microgravity', researchers have been able to dramatically affect the movement and distribution of macromolecules in the fluid, and thus their transport, formation of crystal nuclei, and adsorption to the crystal surface. While a limited number of high quality crystals from space flights have been obtained, as the recent National Research Council (NRC) review of the NASA microgravity crystallization program pointed out, the scientific approach and research in crystallization of proteins has been mainly empirical yielding inconclusive results. We postulate that we can reduce convection in ground-based experiments and we can understand the different aspects of convection control through the use of strong magnetic fields and field gradients. Whether this limited convection in a magnetic field will provide the environment for the growth of high quality crystals is still a matter of conjecture that our research will address. The approach exploits the variation of fluid magnetic susceptibility with concentration for this purpose and the convective damping is realized by appropriately

  10. Induced migration of non-magnetic particles and fabrication of metallic-based graded materials by applying a strong magnetic field

    NASA Astrophysics Data System (ADS)

    Sun, Z.; Guo, M.; Vleugels, J.; Blanpain, B.; Van der Biest, O.

    2011-04-01

    Strong magnetic fields e.g., 10 T are now frequently used during materials preparation. In the present paper, a method of metal-ceramics graded materials preparation is proposed by applying a strong magnetic field with a high gradient. Experimental and theoretical analyses are performed to investigate the effect of the strong magnetic field on the migration and interaction behavior of diamagnetic oxide particles in a liquid metal. The migration of micrometer or sub-micrometer sized particles is clearly enhanced by the magnetic field gradient. After being treated by the strong magnetic field, a self-assembly structure of the particles is achieved. Various factors such as the magnetic dipole-dipole interaction and chain-chain interaction, are governing the particles assembly. The present results provide direct evidence that nonmetallic particles of micrometer size or less can be manipulated in a conductive melt by applying a strong magnetic field and as a consequence graded materials can be prepared.

  11. Study of Fluid Flow Control in Protein Crystallization using Strong Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Ramachandran, Narayanan; Leslie, Fred; Ciszak, Ewa

    2002-11-01

    An important component in biotechnology, particularly in the area of protein engineering and rational drug design is the knowledge of the precise three-dimensional molecular structure of proteins. The quality of structural information obtained from X-ray diffraction methods is directly dependent on the degree of perfection of the protein crystals. As a consequence, the growth of high quality macromolecular crystals for diffraction analyses has been the central focus for biochemists, biologists, and bioengineers. Macromolecular crystals are obtained from solutions that contain the crystallizing species in equilibrium with higher aggregates, ions, precipitants, other possible phases of the protein, foreign particles, the walls of the container, and a likely host of other impurities. By changing transport modes in general, i.e., reduction of convection and sedimentation, as is achieved in "microgravity", researchers have been able to dramatically affect the movement and distribution of macromolecules in the fluid, and thus their transport, formation of crystal nuclei, and adsorption to the crystal surface. While a limited number of high quality crystals from space flights have been obtained, as the recent National Research Council (NRC) review of the NASA microgravity crystallization program pointed out, the scientific approach and research in crystallization of proteins has been mainly empirical yielding inconclusive results. We postulate that we can reduce convection in ground-based experiments and we can understand the different aspects of convection control through the use of strong magnetic fields and field gradients. Whether this limited convection in a magnetic field will provide the environment for the growth of high quality crystals is still a matter of conjecture that our research will address. The approach exploits the variation of fluid magnetic susceptibility with concentration for this purpose and the convective damping is realized by appropriately

  12. Study of Fluid Flow Control in Protein Crystallization using Strong Magnetic Fields

    NASA Technical Reports Server (NTRS)

    Ramachandran, Narayanan; Leslie, Fred; Ciszak, Ewa

    2002-01-01

    An important component in biotechnology, particularly in the area of protein engineering and rational drug design is the knowledge of the precise three-dimensional molecular structure of proteins. The quality of structural information obtained from X-ray diffraction methods is directly dependent on the degree of perfection of the protein crystals. As a consequence, the growth of high quality macromolecular crystals for diffraction analyses has been the central focus for biochemists, biologists, and bioengineers. Macromolecular crystals are obtained from solutions that contain the crystallizing species in equilibrium with higher aggregates, ions, precipitants, other possible phases of the protein, foreign particles, the walls of the container, and a likely host of other impurities. By changing transport modes in general, i.e., reduction of convection and sedimentation, as is achieved in "microgravity", researchers have been able to dramatically affect the movement and distribution of macromolecules in the fluid, and thus their transport, formation of crystal nuclei, and adsorption to the crystal surface. While a limited number of high quality crystals from space flights have been obtained, as the recent National Research Council (NRC) review of the NASA microgravity crystallization program pointed out, the scientific approach and research in crystallization of proteins has been mainly empirical yielding inconclusive results. We postulate that we can reduce convection in ground-based experiments and we can understand the different aspects of convection control through the use of strong magnetic fields and field gradients. Whether this limited convection in a magnetic field will provide the environment for the growth of high quality crystals is still a matter of conjecture that our research will address. The approach exploits the variation of fluid magnetic susceptibility with concentration for this purpose and the convective damping is realized by appropriately

  13. Mixed convection in liquid metal flow in a horizontal duct with strong axial magnetic field

    NASA Astrophysics Data System (ADS)

    Zhang, Xuan; Zikanov, Oleg

    2016-11-01

    The work is motivated by design of self-cooled liquid-metal breeder blankets for Tokamak fusion reactors. Thermal convection caused by non-uniform internal heating in a liquid metal flow in a horizontal duct with strong axial magnetic field is analyzed numerically. Axial magnetic field is considered strong enough (the Hartmann number up to 104 corresponding to typical reactor condition) to suppress the streamwise variation of the flow, so a two-dimensional fully developed flow is studied. Duct walls are assumed to be thermally and electrically insulated. The non-uniform internal heat deposited by captured neutrons is fully diverted by the mean flow. Realistically high Grashof (up to 1011) and Reynolds (up to 106) numbers are considered. It is found that the state of the flow is strongly affected by the vertical stable stratification developing in response to the streamwise growth of mean temperature. Two flow regimes are identified: the regime with developed transverse convection at moderate Grashof numbers, and the regime, in which convection is suppressed at high Grashof numbers. Financial support was provided by the U.S. National Science Foundation (Grant CBET 1435269) and by the University of Michigan - Dearborn.

  14. Disassociation of electrons from partially stripped ion beams due to strong magnetic fields

    SciTech Connect

    Tepikian, S.; Lee, S.Y.

    1989-01-01

    We study the probability of dissociating an electron from partially stripped ions in the AGS. Our calculation indicates that the probability for electron disassociation due to the strong external magnetic field in the AGS is very small for tightly bounded electrons. Two methods are used to estimate this effect: a one-dimensional JWKB method; an energy density approximation. Both methods yield a consistent picture to support the idea of accelerating the partially stripped ions in the AGS, which requires some upgrade in the vacuum pressure due to other processes such as electron capture and ionization. 5 refs., 4 figs.

  15. Rotation, pulsations and magnetic field in V 2052 Ophiuchi: A new He-strong star

    NASA Astrophysics Data System (ADS)

    Neiner, C.; Henrichs, H. F.; Floquet, M.; Frémat, Y.; Preuss, O.; Hubert, A.-M.; Geers, V. C.; Tijani, A. H.; Nichols, J. S.; Jankov, S.

    2003-12-01

    V 2052 Oph is a beta Cep star with v sin i ~ 60 km s-1. The behavior of its stellar wind was studied in the ultraviolet wavelength region with the IUE satellite. It revealed periodic variations in the equivalent widths (EW) of the resonance lines of wind-sensitive ions with a period of 3.638833 d, which is identified as the rotational period. These variations are typical of magnetic stars. Therefore time-resolved circular spectropolarimetric observations were obtained with the Musicos échelle spectropolarimeter at the 2-m Télescope Bernard Lyot (TBL) to search for a magnetic field in the star. Stokes V patterns were observed, the inclination and magnetic angles were derived and a value was determined for the polar magnetic field (250 +/- 190 G) using an oblique rotator dipole model. The spectroscopic information was used to search for periodicity in line-profile variations (lpv), radial velocity and minimum intensity curves. Multiperiodicity was found, corresponding to radial (f_1=7.15 c d-1) and non-radial (f_2=6.82 c d-1, l=3 or 4) pulsation modes. The rotation period is also detected in rotationally modulated observables because of the magnetic poles passing through the observer's line of sight. We determined the stellar parameters of the star, which was found to be chemically peculiar, in particular He-enriched. This makes V 2052 Oph the first magnetic He-strong early B star with known pulsational properties. Based on observations obtained with the MuSiCoS spectropolarimeter at the Observatoire du Pic du Midi, France, and by the International Ultraviolet Explorer, collected at NASA Goddard Space Flight Center and Villafranca Satellite Tracking Station of the European Space Agency, retrieved from the INES database.}\\fnmsep\\thanks{Table \\ref{tabmagV} is only available in electronic form at http://www.edpsciences.org

  16. The onset of layer undulations in smectic A liquid crystals due to a strong magnetic field

    NASA Astrophysics Data System (ADS)

    Contreras, A.; Garcia-Azpeitia, C.; García-Cervera, C. J.; Joo, S.

    2016-08-01

    We investigate the effect of a strong magnetic field on a three dimensional smectic A liquid crystal. We identify a critical field above which the uniform layered state loses stability; this is associated to the onset of layer undulations. In a previous work García-Cervera and Joo (2012 Arch. Ration. Mech. Anal. 203 1-43), García-Cervera and Joo considered the two dimensional case and analyzed the transition to the undulated state via a simple bifurcation. In dimension n  =  3 the situation is more delicate because the first eigenvalue of the corresponding linearized problem is not simple. We overcome the difficulties inherent to this higher dimensional setting by identifying the irreducible representations for natural actions on the functional that take into account the invariances of the problem thus allowing for reducing the bifurcation analysis to a subspace with symmetries. We are able to describe at least two bifurcation branches, highlighting the richer landscape of energy critical states in the three dimensional setting. Finally, we analyze a reduced two dimensional problem, assuming the magnetic field is very strong, and are able to relate this to a model in micromagnetics studied in Alouges et al (2002 ESAIM Control Optim. Calc. Var. 8 31-68), from where we deduce the periodicity property of minimizers.

  17. Spectral manifestations of extremely strong magnetic fields in the sunspot umbra

    NASA Astrophysics Data System (ADS)

    Lozitsky, V. G.

    2017-03-01

    Fine peculiarities of the Zeeman effect in two big sunspots of October 29, 2003, and October 25, 2014, are analyzed. In order to search spectral evidences of very strong spatially unresolved magnetic fields, the Stokes I ± V and V profiles of the Fe I 6301.5 and 6302.5 Å lines are studied in detail. Confirmed are two effects discovered earlier by Lozitsky (2016): (a) non-parallelism of bisectors in the Fe I 6301.5 line at a distance of about ±250 mÅ from the line center and (b) the existence of weak secondary peaks in Stokes V of the Fe I 6302.5 line placed at a distance of, on the average, ±375 mÅ from the line center. Close correlation (r = 0.77 ± 0.06) was found between (a) and (b) effects indicating the reality of very strong (≈8 kG) unresolved magnetic fields. For the first sunspot, the presence of the abovementioned 8-kG fields is traced along 12 Mm of the sunspot umbra. The filling factor is 0.2-0.3 here, and the relative Doppler velocities (without Evershed's effect) are from -1.7 to -3.1 km/s (plasma lifting). Similar parameters were also obtained for the second sunspot.

  18. Cancellation properties in Hall magnetohydrodynamics with a strong guide magnetic field

    NASA Astrophysics Data System (ADS)

    Martin, L. N.; De Vita, G.; Sorriso-Valvo, L.; Dmitruk, P.; Nigro, G.; Primavera, L.; Carbone, V.

    2013-12-01

    We present a signed measure analysis of compressible Hall magnetohydrodynamic turbulence with an external guide field. Signed measure analysis allows us to characterize the scaling behavior of the sign-oscillating flow structures and their geometrical properties (fractal dimensions of structures). A reduced numerical model, valid when a strong guide magnetic field is present, is used here. In order to discuss the effect of the Hall term, different values for the ion skin depth are considered in the simulations. Results show that as the Hall term is increased, the fractal dimension of the current and vorticity sheets decreases. This observation, together with previous analysis of the same fields, provides a comprehensive description of the effect of the Hall force on the formation of structures. Two main processes are identified, namely, the widening and unraveling of the sheets.

  19. Vacuum birefringence in strong magnetic fields: (I) Photon polarization tensor with all the Landau levels

    SciTech Connect

    Hattori, Koichi; Itakura, Kazunori

    2013-03-15

    Photons propagating in strong magnetic fields are subject to a phenomenon called the 'vacuum birefringence' where refractive indices of two physical modes both deviate from unity and are different from each other. We compute the vacuum polarization tensor of a photon in a static and homogeneous magnetic field by utilizing Schwinger's proper-time method, and obtain a series representation as a result of double integrals analytically performed with respect to proper-time variables. The outcome is expressed in terms of an infinite sum of known functions which is plausibly interpreted as summation over all the Landau levels of fermions. Each contribution from infinitely many Landau levels yields a kinematical condition above which the contribution has an imaginary part. This indicates decay of a sufficiently energetic photon into a fermion-antifermion pair with corresponding Landau level indices. Since we do not resort to any approximation, our result is applicable to the calculation of refractive indices in the whole kinematical region of a photon momentum and in any magnitude of the external magnetic field. - Highlights: Black-Right-Pointing-Pointer Vacuum birefringence is studied in the presence of externally applied magnetic field. Black-Right-Pointing-Pointer A general framework is given on the basis of a vacuum polarization tensor of photon. Black-Right-Pointing-Pointer A resummed vacuum polarization tensor is calculated analytically and exactly. Black-Right-Pointing-Pointer Contributions of all the Landau levels are obtained in the form of an infinite sum. Black-Right-Pointing-Pointer Threshold behavior of real-photon decay is obtained at the each Landau level.

  20. Strong Static Magnetic Fields Increase the Gel Signal in Partially Hydrated DPPC/DMPC Membranes.

    PubMed

    Tang, Jennifer; Alsop, Richard J; Schmalzl, Karin; Epand, Richard M; Rheinstädter, Maikel C

    2015-09-29

    NIt was recently reported that static magnetic fields increase lipid order in the hydrophobic membrane core of dehydrated native plant plasma membranes [Poinapen, Soft Matter 9:6804-6813, 2013]. As plasma membranes are multicomponent, highly complex structures, in order to elucidate the origin of this effect, we prepared model membranes consisting of a lipid species with low and high melting temperature. By controlling the temperature, bilayers coexisting of small gel and fluid domains were prepared as a basic model for the plasma membrane core. We studied molecular order in mixed lipid membranes made of dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) using neutron diffraction in the presence of strong static magnetic fields up to 3.5 T. The contribution of the hydrophobic membrane core was highlighted through deuterium labeling the lipid acyl chains. There was no observable effect on lipid organization in fluid or gel domains at high hydration of the membranes. However, lipid order was found to be enhanced at a reduced relative humidity of 43%: a magnetic field of 3.5 T led to an increase of the gel signal in the diffraction patterns of 5%. While all biological materials have weak diamagnetic properties, the corresponding energy is too small to compete against thermal disorder or viscous effects in the case of lipid molecules. We tentatively propose that the interaction between the fatty acid chains' electric moment and the external magnetic field is driving the lipid tails in the hydrophobic membrane core into a better ordered state.

  1. Pair production and annihilation in strong magnetic fields. [of neutron stars and pulsars

    NASA Technical Reports Server (NTRS)

    Daugherty, J. K.; Harding, A. K.

    1983-01-01

    Electromagnetic phenomena occurring in the presence of strong magnetic fields are currently of great interest in high-energy astrophysics. In particular, the process of pair production by single photons in the presence of fields of order 10 to the 12th power Gauss is of importance in cascade models of pulsar gamma ray emission, and may also become significant in theories of other radiation phenomena whose sources may be neutron stars (e.g., gamma ray bursts). In addition to pair production, the inverse process of pair annihilation is greatly affected by the presence of superstrong magnetic fields. The most significant departures from annihilation processes in free space are a reduction in the total rate for annihilation into two photons, a broadening of the familiar 511-keV line for annihilation at rest, and the possibility for annihilation into a single photon which dominates the two-photon annihilation for B (10 to 13th power Gauss) The physics of these pair conversion processes, which is reviewed briefly, can become quite complex in the teragauss regime, and can involve calculations which are technically difficult to incorporate into models of emission mechanisms in neutron star magnetospheres. However, theoretical work, especially the case of pair annihilation, also suggests potential techniques for more direct measurements of field strengths near the stellar surface.

  2. Andreev transport in two-dimensional normal-superconducting systems in strong magnetic fields.

    SciTech Connect

    Khaymovich, I. M.; Chtchelkatchev, N. M.; Shereshevskii, I. A.; Mel'nikov, A. S.; Materials Science Division; Russian Academy of Sciences; L. D. Landau Inst. Theoretical Physics

    2010-01-01

    The conductance in two-dimensional (2D) normal-superconducting (NS) systems is analyzed in the limit of strong magnetic fields when the transport is mediated by the electron-hole states bound to the sample edges and NS interface, i.e., in the Integer Quantum Hall Effect regime. The Andreev-type process of the conversion of the quasiparticle current into the superflow is shown to be strongly affected by the mixing of the edge states localized at the NS and insulating boundaries. The magnetoconductance in 2D NS structures is calculated for both quadratic and Dirac-like normal state spectra. Assuming a random scattering of the edge modes we analyze both the average value and fluctuations of conductance for an arbitrary number of conducting channels.

  3. Charge transfer of He2 + with H in a strong magnetic field

    NASA Astrophysics Data System (ADS)

    Liu, Chun-Lei; Zou, Shi-Yang; He, Bin; Wang, Jian-Guo

    2015-09-01

    By solving a time-dependent Schrödinger equation (TDSE), we studied the electron capture process in the He2 + +H collision system under a strong magnetic field in a wide projectile energy range. The strong enhancement of the total charge transfer cross section is observed for the projectile energy below 2.0 keV/u. With the projectile energy increasing, the cross sections will reduce a little and then increase again, compared with those in the field-free case. The cross sections to the states with different magnetic quantum numbers are presented and analyzed where the influence due to Zeeman splitting is obviously found, especially in the low projectile energy region. The comparison with other models is made and the tendency of the cross section varying with the projectile energy is found closer to that from other close coupling models. Project supported by the National Natural Science Foundation of China (Grants Nos. 11104017, 11025417, 11275029, and 11474032), the National Basic Research Programm of China (Grant No. 2013CB922200), and the Foundation for the Development of Science and Technology of the Chinese Academy of Engineering Physics (Grant Nos. 2014B09036 and 2013A0102005).

  4. MAGNETIC FIELD-DECAY-INDUCED ELECTRON CAPTURES: A STRONG HEAT SOURCE IN MAGNETAR CRUSTS

    SciTech Connect

    Cooper, Randall L.; Kaplan, David L. E-mail: dkaplan@kitp.ucsb.edu

    2010-01-10

    We propose a new heating mechanism in magnetar crusts. Magnetars' crustal magnetic fields are much stronger than their surface fields; therefore, magnetic pressure partially supports the crust against gravity. The crust loses magnetic pressure support as the field decays and must compensate by increasing the electron degeneracy pressure; the accompanying increase in the electron Fermi energy induces nonequilibrium, exothermic electron captures. The total heat released via field-decay electron captures is comparable to the total magnetic energy in the crust. Thus, field-decay electron captures are an important, if not the primary, mechanism powering magnetars' soft X-ray emission.

  5. Electrical conductivity of quark-gluon plasma in strong magnetic fields

    NASA Astrophysics Data System (ADS)

    Hattori, Koichi; Satow, Daisuke

    2016-12-01

    We compute the electrical conductivity of quark-gluon plasma in a strong magnetic field B with quantum field theory at finite temperature using the lowest Landau level approximation. We provide the one-loop result arising from 1-to-2 scattering processes of which the kinematics are satisfied by the (1 +1 )-dimensional fermion dispersion relation. Because of the chirality conservation, the conductivity diverges in the massless limit and is sensitive to the value of the current quark mass. As a result, we find that the conductivity along the direction of the magnetic field is quite large compared with the value at B =0 , mainly because of the small value of the current quark mass. We show that the resummation of the ladder diagrams for the current-current correlator gives rise to only subleading contributions beyond the leading-log order and thus verify our one-loop result at the leading-log accuracy. We also discuss possible implications for the relativistic heavy-ion collisions.

  6. Tiny Stars, Strong Fields: Exploring the Origin of Intense Magnetism in M Stars

    NASA Astrophysics Data System (ADS)

    Toomre, Juri

    . We bring to this our prior experience with studying dynamo processes in the outer convective envelopes of G- (the Sun) and Ftype stars, briefly of M dwarfs, and in full convective cores within more massive A- and B-type stars. Our previous work suggests that M dwarfs could display a broad range of dynamo behavior, from cyclic reversals to more chaotic variations, and further to both weak and strong dynamo states. We will focus on the latter, exploring how superequipartition magnetic fields could be achieved by dynamo action in M dwarfs, as are likely needed to energize super-flares and huge active regions, and what limits the peak field strengths. M-type stars are distinctive in becoming fully convective with decreasing mass at about M3.5 in spectral type (or about 0.35 solar masses). At this transition, a steep rise in the fraction of magnetically active stars is observed that is accompanied by an increasing rotational velocity. Clearly how mass-loss and spin-down can lead to this is of interest in itself. However, here we propose to study the manner in which dynamos operating in fully convective M dwarf interiors beyond the transition may be able to achieve very strong magnetic fields, and how field strengths and apparent magnetic activity increases with rotation rate as suggested by observations. We believe that global connectivity of flows and fields across the core center will admit new classes of strong behavior, as revealed by our B star core dynamos, not realized when a convective envelope is bounded below by a tachocline. These ideas need to be tested in a self-consistent manner with global ASH simulations to gain theoretical insights into what is the origin of the fierce magnetic activity in some of M dwarfs that may be potential hosts to Earth-like planets. Such 3-D MHD simulations, though challenging, are now feasible and would complement the intensive observational searches under way.

  7. Sensitivity Analysis and Simulation of Theoretical Response of Ceramics to Strong Magnetic Fields

    DTIC Science & Technology

    2016-09-01

    magnetic torque energy equation (Eq. 1). Higher values indicate higher model sensitivity, which highlights variables that are more effective for...anisotropic magnetic energy (ΔE), or torque , acting on the particle due to its magnetic anisotropy as a function of the system properties and applied...magnetic torque applied to the particle and the time necessary for rotation can be estimated and used to predict the response of materials to strong

  8. Skyrme model study of proton and neutron properties in a strong magnetic field

    NASA Astrophysics Data System (ADS)

    He, Bing-Ran

    2017-02-01

    The proton and neutron properties in a uniform magnetic field are investigated. The Gell-Mann-Nishijima formula is shown to be satisfied for baryon states. It is found that with increasing magnetic field strength, the proton mass first decreases and then increases, while the neutron mass always increases. The ratio between magnetic moment of proton and neutron increases with the increase of the magnetic field strength. With increasing magnetic field strength, the size of proton first increases and then decreases, while the size of neutron always decreases. The present analysis implies that in the core part of the magnetar, the equation of state depend on the magnetic field, which modifies the mass limit of the magnetar.

  9. Catalytic activity of catalase under strong magnetic fields of up to 8 T

    NASA Astrophysics Data System (ADS)

    Ueno, S.; Iwasaka, M.

    1996-04-01

    The question of whether or not magnetic fields affect enzymatic activity is of considerable interest in biomagnetics and biochemistry. This study focuses on whether magnetically related enzymatic activities can be affected by magnetic fields. We examined the effect of magnetic fields of up to 8 T on catalytic decomposition of hydrogen peroxide (H2O2). We observed changes in absorbance of reaction mixture of hydrogen peroxide and catalase at 240 nm, during and after magnetic field exposures. When the reaction mixture was not treated with nitrogen-gas bubbling, it was observed that the initial reaction rate of the reaction which was exposed to magnetic fields of up to 8 T was 50%-85% lower than the control data. This magnetic field effect was not observed, however, when the reaction mixture was bubbled with nitrogen gas to remove the dissolved oxygen molecules which were produced in the solution. We also measured concentration of dissolved oxygen which was produced by the decomposition of hydrogen peroxide. Dissolved oxygen concentration in the reaction mixture which was exposed to magnetic fields increased 20%-25% compared to the control solution. The results of the present study indicate that magnetic fields affect dynamic movement of oxygen bubbles which are produced in the reaction mixture by the decomposition of hydrogen peroxide, but not the catalytic activity of catalase itself.

  10. Pion production via proton synchrotron radiation in strong magnetic fields in relativistic field theory: Scaling relations and angular distributions

    DOE PAGES

    Maruyama, Tomoyuki; Cheoun, Myung-Ki; Kajino, Toshitaka; ...

    2016-03-26

    We study pion production by proton synchrotron radiation in the presence of a strong magnetic field when the Landau numbers of the initial and final protons are n(i, f) similar to 10(4)-10(5). We find in our relativistic field theory calculations that the pion decay width depends only on the field strength parameter which previously was only conjectured based upon semi-classical arguments. Moreover, we also find new results that the decay width satisfies a robust scaling relation, and that the polar angular distribution of emitted pion momenta is very narrow and can be easily obtained. This scaling implies that one canmore » infer the decay width in more realistic magnetic fields of 10(15) G, where n(i, f) similar to 10(12)-10(13), from the results for n(i, f) similar to 10(4)-10(5). The resultant pion intensity and angular distributions for realistic magnetic field strengths are presented and their physical implications discussed. (C) 2016 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Funded by SCOAP(3).« less

  11. Pion production via proton synchrotron radiation in strong magnetic fields in relativistic field theory: Scaling relations and angular distributions

    SciTech Connect

    Maruyama, Tomoyuki; Cheoun, Myung-Ki; Kajino, Toshitaka; Mathews, Grant J.

    2016-03-26

    We study pion production by proton synchrotron radiation in the presence of a strong magnetic field when the Landau numbers of the initial and final protons are n(i, f) similar to 10(4)-10(5). We find in our relativistic field theory calculations that the pion decay width depends only on the field strength parameter which previously was only conjectured based upon semi-classical arguments. Moreover, we also find new results that the decay width satisfies a robust scaling relation, and that the polar angular distribution of emitted pion momenta is very narrow and can be easily obtained. This scaling implies that one can infer the decay width in more realistic magnetic fields of 10(15) G, where n(i, f) similar to 10(12)-10(13), from the results for n(i, f) similar to 10(4)-10(5). The resultant pion intensity and angular distributions for realistic magnetic field strengths are presented and their physical implications discussed. (C) 2016 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Funded by SCOAP(3).

  12. Integrated nanoplasmonic waveguides for magnetic, nonlinear, and strong-field devices

    NASA Astrophysics Data System (ADS)

    Sederberg, Shawn; Firby, Curtis J.; Greig, Shawn R.; Elezzabi, Abdulhakem Y.

    2017-01-01

    As modern complementary-metal-oxide-semiconductor (CMOS) circuitry rapidly approaches fundamental speed and bandwidth limitations, optical platforms have become promising candidates to circumvent these limits and facilitate massive increases in computational power. To compete with high density CMOS circuitry, optical technology within the plasmonic regime is desirable, because of the sub-diffraction limited confinement of electromagnetic energy, large optical bandwidth, and ultrafast processing capabilities. As such, nanoplasmonic waveguides act as nanoscale conduits for optical signals, thereby forming the backbone of such a platform. In recent years, significant research interest has developed to uncover the fundamental physics governing phenomena occurring within nanoplasmonic waveguides, and to implement unique optical devices. In doing so, a wide variety of material properties have been exploited. CMOS-compatible materials facilitate passive plasmonic routing devices for directing the confined radiation. Magnetic materials facilitate time-reversal symmetry breaking, aiding in the development of nonreciprocal isolators or modulators. Additionally, strong confinement and enhancement of electric fields within such waveguides require the use of materials with high nonlinear coefficients to achieve increased nonlinear optical phenomenon in a nanoscale footprint. Furthermore, this enhancement and confinement of the fields facilitate the study of strong-field effects within the solid-state environment of the waveguide. Here, we review current state-of-the-art physics and applications of nanoplasmonic waveguides pertaining to passive, magnetoplasmonic, nonlinear, and strong-field devices. Such components are essential elements in integrated optical circuitry, and each fulfill specific roles in truly developing a chip-scale plasmonic computing architecture.

  13. Integrated nanoplasmonic waveguides for magnetic, nonlinear, and strong-field devices

    NASA Astrophysics Data System (ADS)

    Sederberg, Shawn; Firby, Curtis J.; Greig, Shawn R.; Elezzabi, Abdulhakem Y.

    2016-11-01

    As modern complementary-metal-oxide-semiconductor (CMOS) circuitry rapidly approaches fundamental speed and bandwidth limitations, optical platforms have become promising candidates to circumvent these limits and facilitate massive increases in computational power. To compete with high density CMOS circuitry, optical technology within the plasmonic regime is desirable, because of the sub-diffraction limited confinement of electromagnetic energy, large optical bandwidth, and ultrafast processing capabilities. As such, nanoplasmonic waveguides act as nanoscale conduits for optical signals, thereby forming the backbone of such a platform. In recent years, significant research interest has developed to uncover the fundamental physics governing phenomena occurring within nanoplasmonic waveguides, and to implement unique optical devices. In doing so, a wide variety of material properties have been exploited. CMOS-compatible materials facilitate passive plasmonic routing devices for directing the confined radiation. Magnetic materials facilitate time-reversal symmetry breaking, aiding in the development of nonreciprocal isolators or modulators. Additionally, strong confinement and enhancement of electric fields within such waveguides require the use of materials with high nonlinear coefficients to achieve increased nonlinear optical phenomenon in a nanoscale footprint. Furthermore, this enhancement and confinement of the fields facilitate the study of strong-field effects within the solid-state environment of the waveguide. Here, we review current state-of-the-art physics and applications of nanoplasmonic waveguides pertaining to passive, magnetoplasmonic, nonlinear, and strong-field devices. Such components are essential elements in integrated optical circuitry, and each fulfill specific roles in truly developing a chip-scale plasmonic computing architecture.

  14. Analysis of the giant magnetostrictive actuator with strong bias magnetic field

    NASA Astrophysics Data System (ADS)

    Xue, Guangming; He, Zhongbo; Li, Dongwei; Yang, Zhaoshu; Zhao, Zhenglong

    2015-11-01

    Giant magnetostrictive actuator with strong bias magnetic field is designed to control the injector bullet valve opening and closing. The relationship between actuator displacement amplitude and input signal direction is analyzed. And based on the approximate linearity of strain-magnetic field, second-order system model of the actuator displacement is established. Experimental system suitable for the actuator is designed. The experimental results show that, the square voltage amplitude being 12 V, the actuator displacement amplitude is about 17 μm with backward direction signal input while being 1.5 μm under forward direction signal. From the results, the suitable input direction is confirmed to be backward. With exciting frequncy lower than 200 Hz, the error between the model and experimental result is less than 1.7 μm. So the model is validated under the low-frequency signal input. The testing displacement-voltage curves are approximately straight lines. But due to the biased position, the line slope and the displacement-voltage linearity change as the input voltage changes.

  15. Properties of strong-coupling magneto-bipolaron qubit in quantum dot under magnetic field

    NASA Astrophysics Data System (ADS)

    Xu-Fang, Bai; Ying, Zhang; Wuyunqimuge; Eerdunchaolu

    2016-07-01

    Based on the variational method of Pekar type, we study the energies and the wave-functions of the ground and the first-excited states of magneto-bipolaron, which is strongly coupled to the LO phonon in a parabolic potential quantum dot under an applied magnetic field, thus built up a quantum dot magneto-bipolaron qubit. The results show that the oscillation period of the probability density of the two electrons in the qubit decreases with increasing electron-phonon coupling strength α, resonant frequency of the magnetic field ω c, confinement strength of the quantum dot ω 0, and dielectric constant ratio of the medium η the probability density of the two electrons in the qubit oscillates periodically with increasing time t, angular coordinate φ 2, and dielectric constant ratio of the medium η the probability of electron appearing near the center of the quantum dot is larger, and the probability of electron appearing away from the center of the quantum dot is much smaller. Project supported by the Natural Science Foundation of Hebei Province, China (Grant No. E2013407119) and the Items of Institution of Higher Education Scientific Research of Hebei Province and Inner Mongolia, China (Grant Nos. ZD20131008, Z2015149, Z2015219, and NJZY14189).

  16. Separability of center of mass and relative motion of hydrogen in very strong magnetic fields

    SciTech Connect

    Palmer, W.F.; Taylor, R.J.

    1980-01-01

    While hydrogen does not strictly separate into center of mass (CMS) and relative motion in a magnetic field, a judicious gauge choice does lead to a simple Hamiltonian whose form in a state of zero translational motion of the center of mass is that of a charged particle in a magnetic field plus a coulomb potential.

  17. Influence of strong magnetic fields on laser pulse propagation in underdense plasma

    NASA Astrophysics Data System (ADS)

    Wilson, T. C.; Li, F. Y.; Weikum, M.; Sheng, Z. M.

    2017-06-01

    We examine the interaction between intense laser pulses and strongly magnetised plasmas in the weakly relativistic regime. An expression for the electron Lorentz factor coupling both relativistic and cyclotron motion nonlinearities is derived for static magnetic fields along the laser propagation axis. This is applied to predict modifications to the refractive index, critical density, group velocity dispersion and power threshold for relativistic self-focusing. It is found that electron quiver response is enhanced under right circularly-polarised light, decreasing the power threshold for various instabilities, while a dampening effect occurs under left circularly-polarised light, increasing the power thresholds. Derived theoretical predictions are tested by one- and three-dimensional particle-in-cell simulations.

  18. Behavior of Particle Depots in Molten Silicon During Float-Zone Growth in Strong Magnetic Fields

    NASA Technical Reports Server (NTRS)

    Jauss, T.; Croell, A.; SorgenFrei, T.; Azizi, M.; Reimann, C.; Friedrich, J.; Volz, M. P.

    2014-01-01

    Solar cells made from directionally solidified silicon cover 57% of the photovoltaic industry's market [1]. One major issue during directional solidification of silicon is the precipitation of foreign phase particles. These particles, mainly SiC and Si3N4, are precipitated from the dissolved crucible coating, which is made of silicon nitride, and the dissolution of carbon monoxide from the furnace atmosphere. Due to their hardness and size of several hundred micrometers, those particles can lead to severe problems during the wire sawing process for wafering the ingots. Additionally, SiC particles can act as a shunt, short circuiting the solar cell. Even if the particles are too small to disturb the wafering process, they can lead to a grit structure of silicon micro grains and serve as sources for dislocations. All of this lowers the yield of solar cells and reduces the performance of cells and modules. We studied the behaviour of SiC particle depots during float-zone growth under an oxide skin, and strong static magnetic fields. For high field strengths of 3T and above and an oxide layer on the sample surface, convection is sufficiently suppressed to create a diffusive like regime, with strongly dampened convection [2, 3]. To investigate the difference between atomically rough phase boundaries and facetted growth, samples with [100] and [111] orientation were processed.

  19. Meson Synchrotron Emission from Central Engines of Gamma-Ray Bursts with Strong Magnetic Fields.

    PubMed

    Tokuhisa; Kajino

    1999-11-10

    Gamma-ray bursts (GRBs) are presumed to be powered by the still unknown central engines with timescales in the range from 1 ms to approximately a few seconds. We propose that the GRB central engines would be a viable site for strong meson synchrotron emission if they were compact astrophysical objects, such as neutron stars or rotating black holes with extremely strong magnetic fields (H approximately 1012-1017 G), and if protons or heavy nuclei were accelerated to ultrarelativistic energies on the order of approximately 1012-1022 eV. We show that the charged scalar mesons like pi+/- and heavy vector mesons like rho, which have several decay modes onto pi+/-, could be emitted, with a high intensity that is a thousand times larger than photons, through strong couplings to ultrarelativistic nucleons. These meson synchrotron emission processes eventually produce a burst of very high energy cosmic neutrinos with 1012 eV

  20. Strong compression of a magnetic field with a laser-accelerated foil.

    PubMed

    Yoneda, Hitoki; Namiki, Tomonori; Nishida, Akinori; Kodama, Ryosuke; Sakawa, Youichi; Kuramitsu, Yasuhiro; Morita, Taichi; Nishio, Kento; Ide, Takao

    2012-09-21

    We demonstrate the generation of high magnetic fields for condensed matter research using a high-power laser system. A cavity in which a seed magnetic field is applied is compressed by a kJ ns laser pulse. The time history of the compressed magnetic field is monitored by observing the Faraday effect rotation of polarization of a probe pulse in a glass fiber. To maintain a low-temperature condition in the final high-field region, we put a high-resistance foil around the final compression area. If we assume the length of the compression region is equal to the laser spot size, a magnetic field of more than 800 T is observed by Faraday rotation. Because of the large mass of the compression foil, this high magnetic field is sustained during almost 2 ns. During compression, a rarefaction wave from the backside of the accelerated foil and expanding material from the inner protection foil affect the magnetic field compression history, but the final compressed magnetic field strength agrees with the ratio between the initial sample area and the compressed cavity area.

  1. The challenge of measuring magnetic fields in strongly pulsating stars: the case of HD 96446

    NASA Astrophysics Data System (ADS)

    Järvinen, S. P.; Hubrig, S.; Ilyin, I.; Schöller, M.; Briquet, M.

    2017-01-01

    Among the early B-type stars, He-rich Bp stars exhibit the strongest large-scale organized magnetic fields with a predominant dipole contribution. The presence of β Cep-like pulsations in the typical magnetic early Bp-type star HD 96446 was announced a few years ago, but the analysis of the magnetic field geometry was hampered by the absence of a reliable rotation period and a sophisticated procedure for accounting for the impact of pulsations on the magnetic field measurements. Using new spectropolarimetric observations and a recently determined rotation period based on an extensive spectroscopic time series, we investigate the magnetic field model parameters of this star under more detailed considerations of the pulsation behaviour of line profiles.

  2. Strong Little Magnets

    ERIC Educational Resources Information Center

    Moloney, Michael J.

    2007-01-01

    Did you know that some strong little cylindrical magnets available in local hardware stores can have an effective circumferential current of 2500 A? This intriguing information can be obtained by hanging a pair of magnets at the center of a coil, as shown in Fig. 1, and measuring the oscillation frequency as a function of coil current.

  3. Strong Little Magnets

    ERIC Educational Resources Information Center

    Moloney, Michael J.

    2007-01-01

    Did you know that some strong little cylindrical magnets available in local hardware stores can have an effective circumferential current of 2500 A? This intriguing information can be obtained by hanging a pair of magnets at the center of a coil, as shown in Fig. 1, and measuring the oscillation frequency as a function of coil current.

  4. Absence of localization in disordered two-dimensional electron gas at weak magnetic field and strong spin-orbit coupling

    PubMed Central

    Su, Ying; Wang, C.; Avishai, Y.; Meir, Yigal; Wang, X. R.

    2016-01-01

    The one-parameter scaling theory of localization predicts that all states in a disordered two-dimensional system with broken time reversal symmetry are localized even in the presence of strong spin-orbit coupling. While at constant strong magnetic fields this paradigm fails (recall the quantum Hall effect), it is believed to hold at weak magnetic fields. Here we explore the nature of quantum states at weak magnetic field and strongly fluctuating spin-orbit coupling, employing highly accurate numerical procedure based on level spacing distribution and transfer matrix technique combined with one parameter finite-size scaling hypothesis. Remarkably, the metallic phase, (known to exist at zero magnetic field), persists also at finite (albeit weak) magnetic fields, and eventually crosses over into a critical phase, which has already been confirmed at high magnetic fields. A schematic phase diagram drawn in the energy-magnetic field plane elucidates the occurrence of localized, metallic and critical phases. In addition, it is shown that nearest-level statistics is determined solely by the symmetry parameter β and follows the Wigner surmise irrespective of whether states are metallic or critical. PMID:27628694

  5. Interaction-driven capacitance in graphene electron-hole double layer in strong magnetic fields

    NASA Astrophysics Data System (ADS)

    Roostaei, Bahman

    2015-12-01

    Fabrication of devices made by isolated graphene layers has opened up possibility of examining highly correlated states of electron systems in parts of their phase diagram that is impossible to access in their counterpart devices such as semiconductor heterostructures. An example of such states are graphene double monolayer electron-hole systems under strong magnetic fields where the separation between layers can be adjusted to be as small as one magnetic length with interlayer tunneling still suppressed. In those separations, it is known that correlations between electrons and holes are of crucial importance and must be included in determination of observable quantities. Here we report the results of our full numerical Hartree-Fock study of coherent and crystalline ground states of the interacting balanced electron-hole graphene systems in small and intermediate separations with each layer occupying up to four lowest lying Landau levels. We show that in the Hartree-Fock approximation the electrons and holes pair to form a homogeneous Bose-condensed (excitonic) state, while crystalline states of such exciton systems remain incoherent at intermediate layer separations. Our results of calculation of capacitance of such states as a function of interlayer separation and filling factor provides quantitative and qualitative signatures that can be examined in real experiments. We show that the capacitance of some crystallized states as well as uniform coherent states are significantly enhanced compared to geometrical values solely due to Coulomb interactions and quantum corrections.

  6. Strong-coupling perturbation theory for the two-dimensional Bose-Hubbard model in a magnetic field

    NASA Astrophysics Data System (ADS)

    Niemeyer, M.; Freericks, J. K.; Monien, H.

    1999-07-01

    The Bose-Hubbard model in an external magnetic field is investigated with strong-coupling perturbation theory. The lowest-order secular equation leads to the problem of a charged particle moving on a lattice in the presence of a magnetic field, which was first treated by Hofstadter. We present phase diagrams for the two-dimensional square and triangular lattices, showing a change in shape of the phase lobes away from the well-known power-law behavior in zero magnetic field. Some qualitative agreement with experimental work on Josephson-junction arrays is found for the insulating phase behavior at small fields.

  7. Effect of a magnetic field on intersubband polaritons in a quantum well: strong to weak coupling conversion.

    PubMed

    Pervishko, A A; Kibis, O V; Shelykh, I A

    2016-08-01

    We investigate theoretically the effect of a magnetic field on intersubband polaritons in an asymmetric quantum well placed inside an optical resonator. It is demonstrated that the field-induced diamagnetic shift of electron subbands in the well increases the broadening of optical lines corresponding to intersubband electron transitions. As a consequence, the magnetic field can switch the polariton system from the regime of strong light-matter coupling to the regime of a weak one. This effect paves a way for the effective control of polaritonic devices with a magnetic field.

  8. Effects of strong magnetic fields on cell growth and radiation response of human T-lymphocytes in culture.

    PubMed

    Norimura, T; Imada, H; Kunugita, N; Yoshida, N; Nikaido, M

    1993-06-01

    Experiments were undertaken in order to verify whether or not a strong magnetic field would have any biological effects on the cell growth, viability and radiation response of mammalian cells. Magnetic field exposures were conducted using a superconducting magnet with freshly-isolated human peripheral blood T-lymphocytes maintained at their normal growing temperature of 37 degrees C. The static magnetic fields with intensities up to 6.3-tesla (T) exerted little influence on the cell growth and viability of actively-growing T-lymphocytes under normal cell-culture conditions. On the other hand, the T cells exposed to the magnetic fields (4 T-6.3 T) during PHA stimulation were inhibited in their cell growth when compared to controls. The effects of the magnetic fields with intensities up to 2 T on cell growth properties, however, were minimal in this system. Also, the radiosensitivity of T-lymphocytes previously exposed to the strong magnetic fields was more sensitive than that of control cells. These results suggest that exposure to a static magnetic field of 4 T or stronger might lead to physiological and growth abnormalities at the cellular level.

  9. Disaggregation of stacked red blood cells under strong pulse magnetic field

    NASA Astrophysics Data System (ADS)

    Hwang, Do-Guwn; Park, Hyeji; Kim, Woori; Lee, Jinyoung; Lee, Hyun Sook

    2015-05-01

    We have investigated the dependence of magnetic field intensity and stimulation time on stacking formation of red blood cells (RBCs) to study blood circulation in human body. The pulse magnetic field with the maximum intensity of 0.27-0.07 T, pulse transition time of 0.102 ms, and pulse intervals of 1 s was applied to the distal end of palm for 5-20 min. The aggregation of RBCs was measured using microscopy. After the magnetic stimulation for 10 min, the fully stacked RBCs were almost separated from each other and moved much faster than those in unstimulated state. The disaggregation was maintained at a decreasing intensity of 0.19 T, and a few cells were stacked at the weak intensity of 0.07 T. In this work, we investigated the degree of RBCs aggregation and activity time by varying the intensity and time of magnetic stimulation to get the optimum condition of pulse magnetic field stimulus.

  10. Influence of a strong longitudinal magnetic field on laser wakefield acceleration

    SciTech Connect

    Rassou, S.; Bourdier, A.; Drouin, M.

    2015-07-15

    Optimization of the beam quality and electronic trapped charge in the cavity are key issues of laser wake field acceleration. The effect of an initially applied uniform magnetic field, parallel to the direction of propagation of the pump pulse, on the laser wakefield is explored. First, an analytic model for the laser wakefield is built up in the case when such an external magnetic field is applied. Then, simulations are performed with a 3D quasi-cylindrical particle in cell code in the blowout (or bubble) regime. Transverse currents are generated at the rear of the bubble which amplify the longitudinal magnetic field. For several plasma and laser parameters, the wake shape is altered and trapping can be reduced or cancelled by the magnetic field. When considering optical injection, and when two counterpropagating waves interact with a rather high plasma density, trapping is not affected by the magnetic field. In this range of plasma and laser parameters, it is shown that the longitudinal magnetic field can reduce or even prevent self-injection and enhance beam quality.

  11. Non-linear development of streaming instabilities in magnetic reconnection with a strong guide field

    NASA Astrophysics Data System (ADS)

    Che, Haihong

    2009-06-01

    Magnetic reconnection has been recognized as a dominant mechanism for converting magnetic energy into the convective and thermal energy of particles, and has been thought as the driver of explosive events in nature and laboratory, such as solar and stellar flares, magnetic substorms and disruptions in fusion experiments. Magnetic reconnection (Sweet-Parker and Petscheck model) is often modeled using resistive magnetohydrodynamics, in which collisions play the key role in facilitating the release of energy in the explosive events. However, in space plasma the collisional resistivity is far below the required resistivity to explain the observed energy release rate. Turbulence is common in plasmas and the anomalous resistivity induced by the turbulence has been proposed as a mechanism for breaking the frozen-in condition in magnetic reconnection. Turbulence-driven resistivity has remained a poorly understood, but widely invoked mechanism for nearly 50 years. The goal of this project is to understand what role anomalous resistivity plays in fast magnetic reconnection. Turbulence has been observed in the intense current layers that develop during magnetic reconnection in the Earth's magnetosphere. Electron streaming is believed to be the source of this turbulence. Using kinetic theory and 3D particlein- cell simulations, we study the nonlinear development of streaming instabilities in 3D magnetic reconnection with a strong guide field. Early in time an intense current sheet develops around the x-line and drives the Buneman instability. Electron holes, which are bipolar spatial localized electric field structures, form and then self-destruct creating a region of strong turbulence around the x-line. At late time turbulence with a characteristic frequency in the lower hybrid range also develops, leading to a very complex mix of interactions. A major challenge is to investigate what occurs after the saturation of Buneman instability and how the momentum and energy are

  12. Regional Mapping of the Lunar Crustal Magnetic Field: Correlation of Strong Anomalies with Curvilinear Albedo Markings

    NASA Technical Reports Server (NTRS)

    Hood, L. L.; Yingst, A.; Zakharian, A.; Lin, R. P.; Mitchell, D. L.; Halekas, J.; Acuna, M. H.; Binder, A. B.

    2000-01-01

    Using high-resolution regional Lunar Prospector magnetometer magnetic field maps, we report here a close correlation of the strongest individual crustal anomalies with unusual curvilinear albedo markings of the Reiner Gamma class.

  13. Neutrons in strong magnetic fields and equation of state of neutron matter

    NASA Astrophysics Data System (ADS)

    Bigdeli, Mohsen

    2017-02-01

    In the present work, I investigate the influence of neutron mass reduction due to magnetic field on the equation of state of neutron matter using the lowest-order constraint variational (LOCV) method with the A V18 potential.

  14. Experimental Realization of Strong Effective Magnetic Fields in an Optical Lattice

    SciTech Connect

    Aidelsburger, M.; Atala, M.; Trotzky, S.; Chen, Y.-A.; Bloch, I.; Nascimbene, S.

    2011-12-16

    We use Raman-assisted tunneling in an optical superlattice to generate large tunable effective magnetic fields for ultracold atoms. When hopping in the lattice, the accumulated phase shift by an atom is equivalent to the Aharonov-Bohm phase of a charged particle exposed to a staggered magnetic field of large magnitude, on the order of 1 flux quantum per plaquette. We study the ground state of this system and observe that the frustration induced by the magnetic field can lead to a degenerate ground state for noninteracting particles. We provide a measurement of the local phase acquired from Raman-induced tunneling, demonstrating time-reversal symmetry breaking of the underlying Hamiltonian. Furthermore, the quantum cyclotron orbit of single atoms in the lattice exposed to the magnetic field is directly revealed.

  15. Scaling and anisotropy in magnetohydrodynamic turbulence in a strong mean magnetic field

    SciTech Connect

    Grappin, Roland; Mueller, Wolf-Christian

    2010-08-15

    We present an analysis of the anisotropic spectral energy distribution in incompressible magnetohydrodynamic turbulence permeated by a strong mean magnetic field. The turbulent flow is generated by high-resolution pseudospectral direct numerical simulations with large-scale isotropic forcing. Examining the radial energy distribution for various angles {theta} with respect to B{sub 0} reveals a specific structure which remains hidden when not taking axial symmetry with respect to B{sub 0} into account. For each direction, starting at the forced large scales, the spectrum first exhibits an amplitude drop around a wave number k{sub 0} which marks the start of a scaling range and goes on up to a dissipative wave number k{sub d}({theta}). The three-dimensional spectrum for k{>=}k{sub 0} is described by a single {theta}-independent functional form F(k/k{sub d}), with the scaling law being the same in every direction. The previous properties still hold when increasing the mean field from B{sub 0}=5 up to B{sub 0}=10b{sub rms}, as well as when passing from resistive to ideal flows. We conjecture that at fixed B{sub 0} the direction-independent scaling regime is reached when increasing the Reynolds number above a threshold which raises with increasing B{sub 0}. Below that threshold critically balanced turbulence is expected.

  16. Origin of strong magnetic fields in Milky Way-like galaxies

    NASA Astrophysics Data System (ADS)

    Beck, Alexander M.

    2016-08-01

    Magnetic fields are observed on all scales in the Universe (see e.g. Kronberg 1994), but little is known about the origin and evolution of those fields with cosmic time. Seed fields of arbitrary source must be amplified to present-day values and distributed among cosmic structures. Therefore, the emergence of cosmic magnetic fields and corresponding dynamo processes (see e.g. Zel'dovich et al. 1983; Kulsrud et al. 1997) can only be jointly understood with the very basic processes of structure and galaxy formation (see e.g. Mo et al. 2010).

  17. Spin Paramagnetism of Cr+++, Fe+++, and Gd+++ at liquid helium temperatures and in strong magnetic fields

    NASA Astrophysics Data System (ADS)

    Henry, Warren E.

    A quantitative experimental study of space quantization of magnetic dipoles and quenching of orbital angular momentum has been made by measuring the fractional variation of the magnetic moment of para magnetic ions with magnetic field strength at fixed temperatures. The study of trivalent chromium ion (4 F 3/2 state for free ion) in potassium chromium alum up to 99.5 percent saturation at 1.29°K and in a field of 50,000 gauss gave a close confirmation of space quantization of magnetic dipoles through compatibility of experimental results with the Brillouin function and very marked incompatibility with the Langevin function. The quenching of orbital angular momentum by the crystalline electric field was demonstrated by the agreement of experimental measurements with a Brillouin function for g=2 (L=0) as against g=2/5 (L=3). The paramagnetic saturation of iron (6 S 5/2 for free ion) ammonium alum and gadolinium (8 S 7/2 for free ion) sulfate octahydrate was achieved, thus permitting of speculation as to a small contribution of the crystalline field to the magnetic moment. Some preliminary calculations were made of this effect for iron ammonium alum and compared with experiment. Experimental study of moments consisted in moving a spherical sample with respect to a double coil system and measuring the flux change ballistically. Magnetic moments were reproducible to ~0.2 percent in mid-range and the magnitude of H/T is known to ~1.5 percent.

  18. SU-E-T-227: Could the Alpha/Beta Ratio Change in a Strong Magnetic Field?

    SciTech Connect

    Pang, G

    2015-06-15

    Purpose: Magnetic resonance imaging (MRI) is being integrated into radiotherapy delivery for MRI-guided radiotherapy. The presence of a strong magnetic field from a MRI machine during radiotherapy delivery presents a new challenge since the trajectories of electrons liberated by ionizing radiation in patients are strongly dependent on the applied magnetic field. The purpose of this work is to explore the potential effect of a strong magnetic field on the α/β ratio, an important radiobiological parameter in radiotherapy. Methods: Based on the theory of dual radiation action, the α/β ratio can be expressed by an integral of the product of two microdosimetry quantities γ(x) and t(x), where γ(x) is the probability that two energy transfers, a distance x apart, results in a lesion, and t(x) is the proximity function, which is the energy-weighted point-pair distribution of distances between energy transfer points in a track. The quantity t(x) depends on the applied magnetic field. An analytical approach has been used to derive a formula that can be used to calculate the α/β ratio in an extremely strong magnetic field. Results: The α/β ratio has been evaluated in the special case when the applied magnetic field approaches infinity, which gives the upper limit of the potential change of the α/β ratio due to the presence of a strong magnetic field. For V79 Chinese hamster cells it has been shown that the α/β ratio could be increased by 2.90 times for Pd-103, 2.97 times for I-125 and about 2.3 times for Co-60 sources when the applied magnetic field approaches infinity. Conclusion: It has been shown theoretically that the α/β ratio can change in a strong magnetic field, and there could be up to a nearly three-fold increase in the α/β ratio, depending on the strength of the applied magnetic field, the cell type and the radiation used.

  19. Estimation of the effects of strong static magnetic fields on plants.

    NASA Astrophysics Data System (ADS)

    Kuznetsov, O.

    In our recent studies we extensively used ponderomotive magnetic forces in high gradient magnetic fields (HGMF) for displacing organelles inside plant gravity receptor cells. Such displacement is a convenient tool both for investigating plant gravity perception mechanism and for physical characterization of the cell interior, and can have future practical applications in providing a directional stimulus for plants in microgravity. This method takes advantage of the magnetic heterogeneity of the receptor cells, namely stronger diamagnetism of starch-filled amyloplasts compared to cytoplasm (? æ < 0). Such particles are repelled from the zones of stronger field in a non-uniform field. To exert a force on amyloplasts, which is comparable to the gravity force, the dynamic factor of the field grad(H2 /2) needs to be 109 - 1 01 0 Oe 2 /cm, and the field intensity in the experimental magnetic systems typically varies from 0 to 2.5-104 Oe, while the size of the area of non-uniformity is 10-2 to 1 cm. Possible effects of such static magnetic fields on plants other than magnetophoresis of amyloplasts were estimated theoretically and tested experimentally. No statistically significant differences in growth rates or rates of gravicurvature were observed in experiments with Linum, Arabidopsis, Hordeum, Avena, Ceratodon and Chara between the plants grown in uniform magnetic fields of various intensities (102 to 2.5-104 Oe) and those grown in the Earth's magnetic field. Microscopic studies also did not detect any structural differences between test and control plants. The magnitudes of possible effects of static magnetic fields on plant cells and organs (including effects on ion currents, magneto-hydrodynamic effects in moving cytoplasm, ponderomotive forces on other cellular structures, effects on some biochemical reactions and biomolecules) were estimated theoretically. The estimations have shown, that these effects are small compared to the thermodynamic noise and thus are

  20. Influence of calculation error of total field anomaly in strongly magnetic environments

    NASA Astrophysics Data System (ADS)

    Yuan, Xiaoyu; Yao, Changli; Zheng, Yuanman; Li, Zelin

    2016-04-01

    An assumption made in many magnetic interpretation techniques is that ΔTact (total field anomaly - the measurement given by total field magnetometers, after we remove the main geomagnetic field, T0) can be approximated mathematically by ΔTpro (the projection of anomalous field vector in the direction of the earth's normal field). In order to meet the demand for high-precision processing of magnetic prospecting, the approximate error E between ΔTact and ΔTpro is studied in this research. Generally speaking, the error E is extremely small when anomalies not greater than about 0.2T0. However, the errorE may be large in highly magnetic environments. This leads to significant effects on subsequent quantitative inference. Therefore, we investigate the error E through numerical experiments of high-susceptibility bodies. A systematic error analysis was made by using a 2-D elliptic cylinder model. Error analysis show that the magnitude of ΔTact is usually larger than that of ΔTpro. This imply that a theoretical anomaly computed without accounting for the error E overestimate the anomaly associated with the body. It is demonstrated through numerical experiments that the error E is obvious and should not be ignored. It is also shown that the curves of ΔTpro and the error E had a certain symmetry when the directions of magnetization and geomagnetic field changed. To be more specific, the Emax (the maximum of the error E) appeared above the center of the magnetic body when the magnetic parameters are determined. Some other characteristics about the error Eare discovered. For instance, the curve of Emax with respect to the latitude was symmetrical on both sides of magnetic equator, and the extremum of the Emax can always be found in the mid-latitudes, and so on. It is also demonstrated that the error Ehas great influence on magnetic processing transformation and inversion results. It is conclude that when the bodies have highly magnetic susceptibilities, the error E can

  1. Internal composition of proto-neutron stars under strong magnetic fields

    NASA Astrophysics Data System (ADS)

    Franzon, B.; Dexheimer, V.; Schramm, S.

    2016-08-01

    In this work, we study the effects of magnetic fields and rotation on the structure and composition of proto-neutron stars. A hadronic chiral SU(3) model is applied to cold neutron stars and proto-neutron stars with trapped neutrinos and at fixed entropy per baryon. We obtain general relativistic solutions for neutron and proto-neutron stars endowed with a poloidal magnetic field by solving Einstein-Maxwell field equations in a self-consistent way. As the neutrino chemical potential decreases in value over time, this alters the chemical equilibrium and the composition inside the star, leading to a change in the structure and in the particle population of these objects. We find that the magnetic field deforms the star and significantly alters the number of trapped neutrinos in the stellar interior, together with strangeness content and temperature in each evolution stage.

  2. Strongly Under-wound and Near-Radial Magnetic Fields in the Solar Wind

    NASA Astrophysics Data System (ADS)

    Murphy, N.; Smith, E.; Schwadron, N.

    2002-12-01

    Observations of the magnetic field orientation in co-rotating rarefaction regions (CRRs) reveal that they are often significantly under-wound compared to the expected Parker spiral, sometimes being almost radial. In particular, CRRs sampled by the Ulysses and Pioneer spacecraft beyond 4 AU from the sun often show average field orientations deviating by more than 30° from the expected Archimedian spiral. These steady state structures last many days, with very little variance in the magnetic field magnitude or direction. The observations are explained by a model combining footpoint motion between fast to slow solar wind streams at the source surface, with the effects of velocity shear across coronal hole boundaries. Using reasonable values for the thickness of and the rate of footpoint transport across the coronal hole boundary, the model reproduces our observations. It also predicts that the magnetic field will evolve asymptotically to a fixed angle and not continue to become more tightly wound with distance.

  3. Electron States and light absorption in strongly oblate and strongly prolate ellipsoidal quantum dots in presence of electrical and magnetic fields.

    PubMed

    Dvoyan, Karen G; Hayrapetyan, David B; Kazaryan, Eduard M; Tshantshapanyan, Ani A

    2007-11-13

    In framework of the adiabatic approximation the energy states of electron as well as direct light absorption are investigated in strongly oblate and strongly prolate ellipsoidal quantum dots (QDs) at presence of electric and magnetic fields. Analytical expressions for particle energy spectrum are obtained. The dependence of energy levels' configuration on QD geometrical parameters and field intensities is analytically obtained. The energy levels of electrons are shown to be equidistant both for strongly oblate and prolate QDs. The effect of the external fields on direct light absorption of a QD was investigated. The dependence of the absorption edge on geometrical parameters of QDs and intensities of the electric and magnetic fields is obtained. Selection rules are obtained at presence as well as absence of external electric and magnetic fields. In particular, it is shown that the presence of the electric field cancels the quantum numbers selection rules at the field direction, whereas in radial direction the selection rules are preserved. Perspectives of practical applications for device manufacturing based on ellipsoidal quantum dots are outlined.

  4. Developmental abnormality induced by strong static magnetic field in Caenorhabditis elegans.

    PubMed

    Wang, Lei; Du, Hua; Guo, Xiaoying; Wang, Xinan; Wang, Meimei; Wang, Yichen; Wang, Min; Chen, Shaopeng; Wu, Lijun; Xu, An

    2015-04-01

    Understanding the effects of strong static magnetic fields (SMFs) on living organisms is significant in health risk assessment, but underlying mechanisms are largely unknown. In the present study, we determined developmental abnormalities induced by 8.5Tesla (T) SMFs in a well-established in vivo model organism, Caenorhabditis elegans (C. elegans). Exposure of C. elegans eggs to 8.5 T SMF resulted in a time-dependent lifespan decrease, whereas only slight changes were observed upon exposure to 5 T SMF. Although SMF exposure did not alter brood size, development rate and stages were significantly modified by 8.5 T SMF. Germ cell apoptosis dramatically increased upon exposure to 8.5 T SMF in adult worms, as confirmed by ced-3 and ced-4 mutants, and could be prevented by concurrent treatment with a free radical scavenger, dimethyl sulfoxide. Compared to wild-type worms, shorter lifespan and greater numbers of apoptotic cells were observed in abnormal methyl viologen sensitivity-1 (mev-1(kn1)) nematodes with increased sensitivity to oxidative damage. Furthermore, exposure to 8.5 T SMF increased expression of superoxide dismutase-3 (sod-3), which is thought to protect against oxidative stress. However, 8.5 T SMF had minimal effects on lifespans of daf-2 and daf-16 mutants, which have compromised insulin/IGF-1 (insulin-like growth factors-1) mediated signaling pathways; this finding was consistent with the expression of these genes in wild-type worms. Our results indicate that developmental toxicity induced by strong SMF in C. elegans is mediated by oxidative stress and may be regulated by the insulin-like receptor pathway.

  5. MULTI-WAVELENGTH STUDY OF A DELTA-SPOT. I. A REGION OF VERY STRONG, HORIZONTAL MAGNETIC FIELD

    SciTech Connect

    Jaeggli, S. A.

    2016-02-10

    Active region NOAA 11035 appeared in 2009 December, early in the new solar activity cycle. This region achieved a delta sunspot (δ spot) configuration when parasitic flux emerged near the rotationally leading magnetic polarity and traveled through the penumbra of the largest sunspot in the group. Both visible and infrared imaging spectropolarimetry of the magnetically sensitive Fe i line pairs at 6302 and 15650 Å show large Zeeman splitting in the penumbra between the parasitic umbra and the main sunspot umbra. The polarized Stokes spectra in the strongest field region display anomalous profiles, and strong blueshifts are seen in an adjacent region. Analysis of the profiles is carried out using a Milne–Eddington inversion code capable of fitting either a single magnetic component with stray light or two independent magnetic components to verify the field strength. The inversion results show that the anomalous profiles cannot be produced by the combination of two profiles with moderate magnetic fields. The largest field strengths are 3500–3800 G in close proximity to blueshifts as strong as 3.8 km s{sup −1}. The strong, nearly horizontal magnetic field seen near the polarity inversion line in this region is difficult to understand in the context of a standard model of sunspot magnetohydrostatic equilibrium.

  6. Multi-wavelength Study of a Delta-spot. I. A Region of Very Strong, Horizontal Magnetic Field

    NASA Astrophysics Data System (ADS)

    Jaeggli, S. A.

    2016-02-01

    Active region NOAA 11035 appeared in 2009 December, early in the new solar activity cycle. This region achieved a delta sunspot (δ spot) configuration when parasitic flux emerged near the rotationally leading magnetic polarity and traveled through the penumbra of the largest sunspot in the group. Both visible and infrared imaging spectropolarimetry of the magnetically sensitive Fe i line pairs at 6302 and 15650 Å show large Zeeman splitting in the penumbra between the parasitic umbra and the main sunspot umbra. The polarized Stokes spectra in the strongest field region display anomalous profiles, and strong blueshifts are seen in an adjacent region. Analysis of the profiles is carried out using a Milne-Eddington inversion code capable of fitting either a single magnetic component with stray light or two independent magnetic components to verify the field strength. The inversion results show that the anomalous profiles cannot be produced by the combination of two profiles with moderate magnetic fields. The largest field strengths are 3500-3800 G in close proximity to blueshifts as strong as 3.8 km s-1. The strong, nearly horizontal magnetic field seen near the polarity inversion line in this region is difficult to understand in the context of a standard model of sunspot magnetohydrostatic equilibrium.

  7. Effects of neutrino emissivity on the cooling of neutron stars in the presence of a strong magnetic field

    SciTech Connect

    Coelho, Eduardo Lenho; Chiapparini, Marcelo; Negreiros, Rodrigo Picanço

    2015-12-17

    One of the most interesting kind of neutron stars are the pulsars, which are highly magnetized neutron stars with fields up to 10{sup 14} G at the surface. The strength of magnetic field in the center of a neutron star remains unknown. According to the scalar virial theorem, magnetic field in the core could be as large as 10{sup 18} G. In this work we study the influence of strong magnetic fields on the cooling of neutron stars coming from direct Urca process. Direct Urca process is an extremely efficient mechanism for cooling a neutron star after its formation. The matter is described using a relativistic mean-field model at zero temperature with eight baryons (baryon octet), electrons and muons. We obtain the relative population of each species of particles as function of baryon density for different magnetic fields. We calculate numerically the cooling of neutron stars for a parametrized magnetic field and compare the results for the case without a magnetic field.

  8. Synthesis of crystallographically oriented olivine aggregates using colloidal processing in a strong magnetic field

    NASA Astrophysics Data System (ADS)

    Koizumi, Sanae; Suzuki, Tohru S.; Sakka, Yoshio; Yabe, Kosuke; Hiraga, Takehiko

    2016-11-01

    This study develops a fabrication technique to obtain Fe-free and Fe-bearing (Fe:Mg = 1:9) olivine aggregates not only with high density and fine grain size but with crystallographic preferred orientation (CPO). A magnetic field (≤12 T) is applied to synthetic, fine-grained ( 120 nm), olivine particles dispersed in solvent. The alignment of certain crystallographic axes of the particles with respect to a magnetic direction is anticipated due to magnetic anisotropy of olivine. The dispersed particles are gradually consolidated on a porous alumina mold covered with a solid-liquid separation filter during drainage of the solvent. The resultant aligned consolidated aggregate is then isostatically pressed and vacuum sintered. We find that (1) preparation of fully reacted olivine particles, with less propensity to coalesce; (2) preparation of a suspension with highly dispersed particles; and (3) application of a certain strength of the magnetic field are essential to obtain well-sintered and well-aligned aggregates. High density (i.e., <1 vol% porosity) and fine grain size ( 1 μm) Fe-free and Fe-bearing olivine aggregates were successfully synthesized with uniaxially aligned a- and c-axes, respectively. Attempts to uniaxially align the magnetization hard axis and to triaxially align Fe-bearing olivine by rotating the suspension in the magnetic field succeeded in obtaining weakly developed CPO aggregates.

  9. Coupled-cluster theory for atoms and molecules in strong magnetic fields

    SciTech Connect

    Stopkowicz, Stella Lange, Kai K.; Tellgren, Erik I.; Helgaker, Trygve; Gauss, Jürgen

    2015-08-21

    An implementation of coupled-cluster (CC) theory to treat atoms and molecules in finite magnetic fields is presented. The main challenges for the implementation stem from the magnetic-field dependence in the Hamiltonian, or, more precisely, the appearance of the angular momentum operator, due to which the wave function becomes complex and which introduces a gauge-origin dependence. For this reason, an implementation of a complex CC code is required together with the use of gauge-including atomic orbitals to ensure gauge-origin independence. Results of coupled-cluster singles–doubles–perturbative-triples (CCSD(T)) calculations are presented for atoms and molecules with a focus on the dependence of correlation and binding energies on the magnetic field.

  10. Pion and σ-meson Properties in a Strong Magnetic Field

    NASA Astrophysics Data System (ADS)

    Zhang, Rui; Fu, Wei-Jie; Liu, Yu-Xin

    2015-09-01

    With the Nambu-Jona-Lasinio (NJL) model we calculate the properties of pion and σ-meson at finite temperature and finite magnetic field. The obtained temperature and magnetic field strength dependence of the constituent quark mass M, the pion and σ-meson masses and the neutral pion decay constant indicates that, in the simple four fermion interaction model, there exists the magnetic catalysis effect. It also shows that the Gell-Mann-Oakes-Renner relation is violated obviously with the increasing of the temperature, and the effect of the magnetic field becomes pronounced only around the critical temperature. The deviation of the critical temperatures obtained with different criteria indicates that the chiral phase transition driven by the temperature in the magnetic field strength region we have considered is in fact a crossover. Supported by the National Natural Science Foundation of China under Grant Nos. 10935001, 11175004, and 11435001, and the National Key Basic Research Program of China under Grant Nos. G2013CB834400 and G2015CB856900

  11. Effect of a strong magnetic field on the energy yield of nuclear reactions in dense nuclear matter

    SciTech Connect

    Sekerzhitskii, V.S.

    1995-01-01

    According to modern concepts, the electron-neutron-nuclear (Aen) phase of dense highly degenerate matter can be realized in the shells of neutron stars. This phase has relatively stable and absolutely stable states of thermodynamic equilibrium. Strong magnetic fields can exist in neutron stars. For this reason, analysis of their effect on the characteristics of the Aen phase is of great interest. It is specially important to study the influence of strong magnetic fields on the energy yield of nuclear reactions in dense nuclear matter because the transition to the absolute equilibrium state proceeds through these reactions.

  12. Direct laser acceleration of electrons in a strong azimuthal magnetic field

    NASA Astrophysics Data System (ADS)

    Wang, Tao; Toncian, Toma; Stark, David; Arefiev, Alexey

    2016-10-01

    Recently published particle-in-cell simulations indicate that a high-intensity laser irradiating an over-critical plasma can induce relativistic transparency and drive a Megatesla magnetic field while propagating into the plasma. At the same time, the quasi-static electric field in this regime is an order of magnitude weaker than the quasi-static magnetic field as a result of ion mobility and the fact that electrons are irradiated by a high intensity laser pulse. We have examined analytically and numerically direct laser acceleration of electrons in such an azimuthal magnetic field. We have considered a general case of a laser beam propagating with a superluminal phase velocity and compared the results to those for a luminal case. Our key finding is that the maximum gamma-factor that can be attained by electrons has a pronounced threshold, with a significant enhancement of the electron energy taking place above the threshold. The threshold is a function of the azimuthal magnetic field and of the initial transverse electron momentum. This work was supported by the National Science Foundation under Grant No. 1632777.

  13. Hunting For Strong Magnetic Fields In Rapidly Rotating Sun-Like Stars With Stokes-I Observations

    NASA Astrophysics Data System (ADS)

    Shulyak, Denis; Malo, Lison; Reiners, Ansgar; Kochukhov, Oleg; Jeffers, Sandra; Piskunov, Nikolai

    2016-06-01

    Stars with convective envelopes can generate strong magnetic fields through rotationally driven dynamos. Theory suggests that the maximum magnetic field strength depends on the energy budget stored in the stellar convective shell and can reach values of several kilogauss in fastest rotating stars. We test this predictions by measuring total magnetic flux and polarization in a sample of sun-like stars that rotate close to the activity saturation limit. We detect average magnetic flux densities of several hundred G in several of our targets,with the strongest field of about 1 kG in a K type star V383 Lac showing that young sun-like starscan produce average fields on the kG level.

  14. Hall viscosity and momentum transport in lattice and continuum models of the integer quantum Hall effect in strong magnetic fields

    NASA Astrophysics Data System (ADS)

    Tuegel, Thomas I.; Hughes, Taylor L.

    2015-10-01

    The Hall viscosity describes a nondissipative response to strain in systems with broken time-reversal symmetry. We develop a method for computing the Hall viscosity of lattice systems in strong magnetic fields based on momentum transport, which we compare to the method of momentum polarization used by Tu et al. [Phys. Rev. B 88, 195412 (2013), 10.1103/PhysRevB.88.195412] and Zaletel et al. [Phys. Rev. Lett. 110, 236801 (2013), 10.1103/PhysRevLett.110.236801] for noninteracting systems. We compare the Hall viscosity of square-lattice tight-binding models in magnetic field to the continuum integer quantum Hall effect (IQHE) showing agreement when the magnetic length is much larger than the lattice constant, but deviation as the magnetic field strength increases. We also relate the Hall viscosity of relativistic electrons in magnetic field (the Dirac IQHE) to the conventional IQHE. The Hall viscosity of the lattice Dirac model in magnetic field agrees with the continuum Dirac Hall viscosity when the magnetic length is much larger than the lattice constant. We also show that the Hall viscosity of the lattice model deviates further from the continuum model if the C4 symmetry of the square lattice is broken to C2, but the deviation is again minimized as the magnetic length increases.

  15. Energy loss of a nonaccelerating quark moving through a strongly coupled N =4 super Yang-Mills vacuum or plasma in strong magnetic field

    NASA Astrophysics Data System (ADS)

    Mamo, Kiminad A.

    2016-08-01

    Using AdS /CFT correspondence, we find that a massless quark moving at the speed of light v =1 , in arbitrary direction, through a strongly coupled N =4 super Yang-Mills (SYM) vacuum at T =0 , in the presence of strong magnetic field B , loses its energy at a rate linearly dependent on B , i.e., d/E d t =-√{λ/} 6 π B . We also show that a heavy quark of mass M ≠0 moving at near the speed of light v2=v*2=1 -4/π2T2 B ≃1 , in arbitrary direction, through a strongly coupled N =4 SYM plasma at finite temperature T ≠0 , in the presence of strong magnetic field B ≫T2, loses its energy at a rate linearly dependent on B , i.e., d/E d t =-√{λ/}6 π B v*2≃-√{λ/}6 π B . Moreover, we argue that, in the strong magnetic field B ≫T2 (IR) regime, N =4 SYM and adjoint QCD theories (when the adjoint QCD theory has four flavors of Weyl fermions and is at its conformal IR fixed point λ =λ*) have the same microscopic degrees of freedom (i.e., gluons and lowest Landau levels of Weyl fermions) even though they have quite different microscopic degrees of freedom in the UV when we consider higher Landau levels. Therefore, in the strong magnetic field B ≫T2 (IR) regime, the thermodynamic and hydrodynamic properties of N =4 SYM and adjoint QCD plasmas, as well as the rates of energy loss of a quark moving through the plasmas, should be the same.

  16. Generation of strong quasistatic magnetic fields in interactions of ultraintense and short laser pulses with overdense plasma targets

    SciTech Connect

    Cai Hongbo; Zhu Shaoping; Zhou Cangtao; Yu Wei

    2007-09-15

    An analytical fluid model is proposed for the generation of strong quasistatic magnetic fields during normal incidence of a short ultraintense Gaussian laser pulse with a finite spot size on an overdense plasma. The steepening of the electron density profile in the originally homogeneous overdense plasma and the formation of electron cavitation as the electrons are pushed inward by the laser are included self-consistently. It is shown that the appearance of the cavitation plays an important role in the generation of quasistatic magnetic fields: the strong plasma inhomogeneities caused by the formation of the electron cavitation lead to the generation of a strong axial quasistatic magnetic field B{sub z}. In the overdense regime, the generated quasistatic magnetic field increases with increasing laser intensity, while it decreases with increasing plasma density. It is also found that, in a moderately overdense plasma, highly intense laser pulses can generate magnetic fields {approx}100 MG and greater due to the transverse linear mode conversion process.

  17. Landau levels of cold dense quark matter in a strong magnetic field

    NASA Astrophysics Data System (ADS)

    Wen, Xin-Jian; Liang, Jun-Jun

    2016-07-01

    The occupied Landau levels of strange quark matter are investigated in the framework of the SU(3) NJL model with a conventional coupling and a magnetic-field dependent coupling respectively. At lower density, the Landau levels are mainly dominated by u and d quarks. Threshold values of the chemical potential for the s quark onset are shown in the μ -B plane. The magnetic-field-dependent running coupling can broaden the region of three-flavor matter by decreasing the dynamical masses of s quarks. Before the onset of s quarks, the Landau level number of light quarks is directly dependent on the magnetic field strength B by a simple inverse proportional relation ki ,max≈Bi0/B with Bd0=5 ×1 019 G , which is approximately 2 times Bu0 of u quarks at a common chemical potential. When the magnetic field increases up to Bd0, almost all three flavors are lying in the lowest Landau level.

  18. Magnetic field geometry and chemical abundance distribution of the He-strong star CPD -57°3509

    NASA Astrophysics Data System (ADS)

    Hubrig, S.; Przybilla, N.; Korhonen, H.; Ilyin, I.; Schöller, M.; Järvinen, S. P.; Nieva, M.-F.; Scholz, R.-D.; Kimeswenger, S.; Ramolla, M.; Kholtygin, A. F.; Briquet, M.

    2017-10-01

    The magnetic field of CPD -57°3509 was recently detected in the framework of the BOB (B fields in OB stars) collaboration. We acquired low-resolution spectropolarimetric observations of CPD -57°3509 with the FOcal Reducer low-dispersion Spectrograph 2 and high-resolution UV-Visual Echelle Spectrograph observations randomly distributed over a few months to search for periodicity, to study the magnetic field geometry and to determine the surface distribution of silicon and helium. We also obtained supplementary photometric observations at a timeline similar to the spectroscopic and spectropolarimetric observations. A period of 6.36 d was detected in the measurements of the mean longitudinal magnetic field. A sinusoidal fit to our measurements allowed us to constrain the magnetic field geometry and estimate the dipole strength in the range of 3.9-4.5 kG. Our application of the Doppler imaging technique revealed the presence of He I spots located around the magnetic poles, with a strong concentration at the positive pole and a weaker one around the negative pole. In contrast, high-concentration Si III spots are located close to the magnetic equator. Furthermore, our analysis of the spectral variability of CPD -57°3509 on short time-scales indicates distinct changes in shape and position of line profiles possibly caused by the presence of β Cep like pulsations. A small periodic variability in line with the changes of the magnetic field strength is clearly seen in the photometric data.

  19. Heavy quark diffusion in strong magnetic fields at weak coupling and implications for elliptic flow

    DOE PAGES

    Fukushima, Kenji; Hattori, Koichi; Yee, Ho -Ung; ...

    2016-04-20

    In this paper, we compute the momentum diffusion coefficients of heavy quarks, κ∥ and κ⊥, in a strong magnetic field B along the directions parallel and perpendicular to B, respectively, at the leading order in QCD coupling constant αs. We consider a regime relevant for the relativistic heavy ion collisions, αseB << T2 << eB, so that thermal excitations of light quarks are restricted to the lowest Landau level (LLL) states. In the vanishing light-quark mass limit, we find κLO⊥ ∝ α2sTeB in the leading order that arises from screened Coulomb scatterings with (1+1)-dimensional LLL quarks, while κ∥ gets nomore » contribution from the scatterings with LLL quarks due to kinematic restrictions. We show that the first nonzero leading order contributions to κLO∥ come from the two separate effects: 1) the screened Coulomb scatterings with thermal gluons, and 2) a finite light-quark mass mq. The former leads to κLO,gluon∥ ∝ α2sT3 and the latter to κLO,massive∥ ∝ αs(αseB)1/2m2q. Based on our results, we propose a new scenario for the large value of heavy-quark elliptic flow observed in RHIC and LHC. Namely, when κ⊥ >> κ∥, an anisotropy in drag forces gives rise to a sizable amount of the heavy-quark elliptic flow even if heavy quarks do not fully belong to an ellipsoidally expanding background fluid.« less

  20. THE DISCOVERY OF A STRONG MAGNETIC FIELD AND COROTATING MAGNETOSPHERE IN THE HELIUM-WEAK STAR HD 176582

    SciTech Connect

    Bohlender, David A.; Monin, Dmitry

    2011-05-15

    We report the detection of a strong, reversing magnetic field and variable H{alpha} emission in the bright helium-weak star HD 176582 (HR 7185). Spectrum, magnetic, and photometric variability of the star are all consistent with a precisely determined period of 1.5819840 {+-} 0.0000030 days which we assume to be the rotation period of the star. From the magnetic field curve, and assuming a simple dipolar field geometry, we derive a polar field strength of approximately 7 kG and a lower limit of 52 deg. for the inclination of the rotation axis. However, based on the behavior of the H{alpha} emission, we adopt a large inclination angle of 85 deg. and this leads to a large magnetic obliquity of 77{sup 0}. The H{alpha} emission arises from two distinct regions located at the intersections of the magnetic and rotation equators and which corotate with the star at a distance of about 3.5 R{sub *} above its surface. We estimate that the emitting regions have radial and meridional sizes on the order of 2 R{sub *} and azimuthal extents (perpendicular to the magnetic equator) of less than approximately 0.6 R{sub *}. HD 176582 therefore appears to show many of the cool magnetospheric phenomena as that displayed by other magnetic helium-weak and helium-strong stars such as the prototypical helium-strong star {sigma} Ori E. The observations are consistent with current models of magnetically confined winds and rigidly rotating magnetospheres for magnetic Bp stars.

  1. Statistical Plasma Physics in a Strong Magnetic Field: Paradigms and Problems

    SciTech Connect

    J.A. Krommes

    2004-03-19

    An overview is given of certain aspects of fundamental statistical theories as applied to strongly magnetized plasmas. Emphasis is given to the gyrokinetic formalism, the historical development of realizable Markovian closures, and recent results in the statistical theory of turbulent generation of long-wavelength flows that generalize and provide further physical insight to classic calculations of eddy viscosity. A Hamiltonian formulation of turbulent flow generation is described and argued to be very useful.

  2. Ground state of the hydrogen molecule in a strong magnetic field

    NASA Astrophysics Data System (ADS)

    Kravchenko, Yu. P.; Liberman, M. A.

    1997-10-01

    The ground state of a hydrogen molecule in magnetic fields is investigated using a fully numerical Hartree-Fock approach. We found that between 4.2×104 T and 3×106 T the ground state is 3Σ+u with very weak interaction between atoms. In this field region the hydrogen can form a superfluid phase, predicted earlier [Korolev and Liberman, Phys. Rev. Lett. 72, 270 (1994)]; the state 3Πu is metastable and may be responsible for the unknown excitonic line observed by Timofeev and Chernenko [JETP Lett. 61, 617 (1995)]. For magnetic fields stronger than 3×106 T the ground state is the tightly bound 3Πu.

  3. Laboratory Experiment of Magnetic Reconnection between Merging Flux Tubes with Strong Guide FIeld

    NASA Astrophysics Data System (ADS)

    Inomoto, M.; Kamio, S.; Kuwahata, A.; Ono, Y.

    2013-12-01

    Magnetic reconnection governs variety of energy release events in the universe, such as solar flares, geomagnetic substorms, and sawtooth crash in laboratory nuclear fusion experiments. Differently from the classical steady reconnection models, non-steady behavior of magnetic reconnection is often observed. In solar flares, intermittent enhancement of HXR emission is observed synchronously with multiple ejection of plammoids [1]. In laboratory reconnection experiments, the existence of the guide field, that is perpendicular to the reconnection field, makes significant changes on reconnection process. Generally the guide field will slow down the reconnection rate due to the increased magnetic pressure inside the current sheet. It also brings about asymmetric structure of the separatrices or effective particle acceleration in collisionless conditions. We have conducted laboratory experiments to study the behavior of the guide-field magnetic reconnection using plasma merging technique (push reconnection). Under substantial guide field even larger than the reconnection field, the reconnection generally exhibits non-steady feature which involves intermittent detachment of X-point and reconnection current center[2]. Transient enhancement of reconnection rate is observed simultaneously with the X-point motion[3]. We found two distinct phenomena associated with the guide-field non-steady reconnection. The one is the temporal and localized He II emission from X-point region, suggesting the production of energetic electrons which could excite the He ions in the vicinity of the X-point. The other is the excitation of large-amplitude electromagnetic waves which have similar properties with kinetic Alfven waves, whose amplitude show positive correlation with the enhancement of the reconnection electric field[4]. Electron beam instability caused by the energetic electrons accelerated to more than twice of the electron thermal velocity could be a potential driver of the

  4. Nonlinear dispersion of resonance extraordinary wave in a plasma with strong magnetic field

    SciTech Connect

    Krasovitskiy, V. B.; Turikov, V. A.; Sotnikov, V. I.

    2007-09-15

    In this paper, the efficiency of electron acceleration by a short, powerful laser pulse propagating across an external magnetic field is investigated. Conditions for the decay of a laser pulse with frequency close to the upper hybrid resonance frequency are analyzed. It is also shown that a laser pulse propagating as an extraordinary wave in cold, magnetized, low-density plasma takes the form of a nonlinear wave with the modulated amplitude (envelope soliton). Finally, simulation results on the interaction of an electromagnetic pulse with a semi-infinite plasma, obtained with the help of an electromagnetic relativistic PIC code, are discussed and a comparison with the obtained theoretical results is presented.

  5. Experimental study of the response of CZT and CdTe detectors of various thicknesses in strong magnetic field

    NASA Astrophysics Data System (ADS)

    Tan, J. W.; Cai, L.; Meng, L. J.

    2011-10-01

    In this paper, we used a combined experimental and Monte Carlo simulation approach to investigate the detailed charge collection process within thick CdTe/CZT detectors operated inside a strong magnetic field. As one of the key objectives, we quantitatively assessed the effect of the Lorenz force on the migration of charge carriers inside the detector bulk. This information would allow an accurate modeling of the detector's response to gamma ray interactions and therefore help to compensate for the event-positioning error induced by the strong magnetic field. In this study, a pixilated ERPC detector with 350 μm square pixels was set on a non-magnetic gantry and operated inside a 3 T Siemens MRI scanner. Multiple studies, with similar geometries, were performed using the same detector setup with and without the presence of the magnetic field to investigate the effect on the charge collection behavior from the strong magnetic field. The experimental results were used to validate the Monte Carlo simulation package that models both photon transportation and charge collection process inside the detector.

  6. Kinetic equilibrium of beta-processes in high-temperature, superdense matter with a strong frozen-in magnetic field

    SciTech Connect

    Ivanov, M.A.; Shul'man, G.A.

    1980-05-01

    An analysis is given of the kinetic equilibrium of ..beta..-processes in high-temperature, superdense, strongly magnetized matter. The ratio theta/sup H/ of the neutron and proton number densities in a quantizing magnetic field is evaluated. Numerical calculations show that if the electrons (or positrons) have a large chemical potential, the value of theta/sup H/ in an ultrastrong magnetic field will be much lower than the corresponding ratio theta/sub 0/ when H=0, while if there are small departures from equilibrium the relaxation time of the ..beta..-processes will be about half as long as in the field-free case. The processes discussed may be useful for describing the evolution of massive, highly magnetized stars at the stage just prior to a supernova explosion.

  7. The crystallization of apo-form UMP kinase from Xanthomonas campestris is significantly improved in a strong magnetic field

    SciTech Connect

    Tu, Jhe-Le; Chin, Ko-Hsin; Wang, Andrew H.-J.; Chou, Shan-Ho

    2007-05-01

    A bacterial UMP kinase from the plant pathogen X. campestris pathovar campestris has been overexpressed in E. coli, purified and crystallized in a strong magnetic field. The crystals diffracted to 2.35 Å. Bacterial UMP kinases (UMPKs) are crucial enzymes that are responsible for microbial UTP biosynthesis. Interestingly, eukaryotic and prokaryotic cells use different enzymes for UMP-phosphorylation reactions. Prokaryotic UMPKs are thus believed to be potential targets for antimicrobial drug development. Here, the cloning, expression and crystallization of SeMet-substituted XC1936, a bacterial UMPK from Xanthomonas campestris pathovar campestris, are reported. The crystallization of the apo-form UMPK was found to be significantly improved in a strong magnetic field; the crystals diffracted to a resolution of 2.35 Å, a dramatic improvement over the original value of 3.6 Å. Preliminary structural analyses of apo-form XC1936 using crystals grown in a strong magnetic field clearly reveal well defined loop regions involved in substrate-analogue binding that were previously not visible. Crystallization in a strong magnetic field thus was found to be indispensable in determining the flexible region of the XC1936 UMPK structure.

  8. Strong Field Ionization Rate Depends on the Sign of the Magnetic Quantum Number

    DTIC Science & Technology

    2013-04-01

    xenon and krypton . It was found that spin-orbital coupling does not suppress the dependency of strong field ionization on atomic orientation. These...both   xenon  and   krypton .  It  was  found  that  spin-­‐orbital  coupling  does  not  suppress  the   dependency  of...spin-­‐orbital   coupling   in   krypton   and   xenon  does   not   suppress   the   dependency  of  strong  field

  9. Exact spectra of strong coulomb correlations of 3-D 2-e harmonic dots in magnetic field

    NASA Astrophysics Data System (ADS)

    Aggarwal, Priyanka; Sharma, Shivalika; Kaur, Harsimran; Singh, Sunny; Hazra, Ram Kuntal

    2017-01-01

    Applications of 3-D 2-e systems have proliferated very fast due to technological advancements in wide range of phenomena from atomic landscape to mesoscopic scale. The unusual properties of atomic/mesoscopic systems are the results of interplaying charge interactions among different bound states. The non-trivial e-e correlations in electrically and/or magnetically confined systems improvise wealth of intriguing challenges at fundamental level due to lack of exact solution of Schrödinger equations. For the first time, a novel methodology of exactly finite summed coulomb correlations invented by us is so handy that even usual programmable calculator can be used to examine the electronic structures of 3-D 2-e harmonic dots in perpendicular magnetic field (symmetric gauge). Statistics of electronic levels, heat capacity measurements and magnetization (T∼1 K) are also investigated in brief to probe the degree of disorderedness.

  10. Current-density functional theory study of the H2 molecule evolving under a strong ultrashort magnetic field

    NASA Astrophysics Data System (ADS)

    Vikas, Hash(0xb7f6e60)

    2012-01-01

    Hydrogen molecule in a strong ultrashort magnetic field is investigated through a current-density functional theory (CDFT) and quantum fluid dynamics (QFD) based approach employing current-density dependent vector exchange-correlation potential and energy density functional derived with a vorticity variable. The numerical computations through the CDFT based approach are performed for the H2 molecule, starting initially from its field-free ground state, in a parallel internuclear axis and magnetic field-axis configuration with the internuclear separation R ranging from 0.1 a.u. to 14.0 a.u., and the strength of the time-dependent (TD) magnetic field varying between 0-1011 G over a few femtoseconds. The numerical results are compared with that obtained using an approach based on the current-density independent approximation under similar computational constraints but employing only scalar exchange-correlation potential dependent on the electronic charge-density alone. The current-density based approach yields exchange- and correlation energy as well as electronic charge-density of the H2 molecule drastically different from that obtained using current-independent approach, in particular, at TD magnetic field-strengths >109 G during a typical time-period of the field when the magnetic-field had attained maximum applied field-strength and is switched to a decreasing ramp function. This nonadiabatic behavior of the TD electronic charge-density is traced to the TD vorticity-dependent vector exchange-correlation potential of the CDFT based approach. The interesting electron dynamics of the H2 molecule in strong TD magnetic field is further elucidated by treating electronic charge-density as an `electron-fluid'. The present work also reveals interesting real-time dynamics on the attosecond time-scale in the electronic charge-density distribution of the hydrogen molecule.

  11. The sharp-front magnetic diffusion wave of a strong magnetic field diffusing into a solid metal

    NASA Astrophysics Data System (ADS)

    Xiao, Bo; Gu, Zhuo-Wei; Kan, Ming-Xian; Wang, Gang-Hua; Zhao, Jian-Heng; Computational Physics Team

    2016-10-01

    When a mega-gauss magnetic field diffuses into a solid metal, the Joule heat would rise rapidly the temperature of the metal, and the rise of temperature leads to an increase of the metal's resistance, which in turn accelerates the magnetic field diffusion. Those positive feedbacks acting iteratively would lead to an interesting sharp-front magnetic diffusion wave. By assuming that the metal's resistance has an abrupt change from a small value ηS to larger value ηL at some critical temperature Tc, the sharp-front magnetic diffusion wave can be solved analytically. The conditions for the emerging of the sharp-front magnetic diffusion wave are B0 >Bc , ηL /ηS >> 1 , and ηL/ηSB0/-Bc Bc >> 1 , where Bc =√{ 2μ0Jc } , B0 is the vacuum magnetic field strength, and Jc is the critical Joule heat density. The wave-front velocity of the diffusion wave is Vc =ηL/μ0B0/-Bc Bc1/xc , where xc is the depth the wave have propagated in the metal. In this presentation we would like to discuss the derivation of the formulas and its impact to magnetically driven experiments. The work is supported by the Foundation of China Academy of Engineering Physics (No. 2015B0201023).

  12. Distribution of plasma and magnetic field in the Venus induced magnetosphere is strongly asymmetrical

    NASA Astrophysics Data System (ADS)

    Dubinin, E.; Fraenz, M.; Zhang, T.-L.; Woch, J.; Wei, Y.; Fedorov, A.; Barabash, S.; Lundin, R.

    2013-09-01

    Venus Express spacecraft have provided us a wealth of in-situ observations of characteristics of induced magnetosphere of Venus. One of its important features is a distinct asymmetry in plasma and field characteristics between the hemisphere pointed in the direction of the motional electric field and the opposite hemisphere. Asymmetry starts from formation of the magnetic barrier, then continues to low altitudes where effects of finite conductivity become important and further to the near Venus tail where the magnetic tail and plasma sheet are formed. As a result, the structure and dynamics of the induced magnetosphere in both hemispheres occur different. We present different aspects of such an asymmetry and discuss possible mechanisms of its appearance.

  13. Distribution of plasma and magnetic field in the Venus induced magnetosphere is strongly asymmetrical

    NASA Astrophysics Data System (ADS)

    Dubinin, E.; Fraenz, M.; Zhang, T.; Woch, J. G.; Wei, Y.; Fedorov, A.; Barabash, S. V.; Lundin, R. N.

    2013-12-01

    Venus Express spacecraft have provided us a wealth of in-situ observations of characteristics of induced magnetosphere of Venus. One of its important features is a distinct asymmetry in plasma and field characteristics between the hemisphere pointed in the direction of the motional electric field and the opposite hemisphere. Asymmetry starts from formation of the magnetic barrier, then continues to low altitudes where effects of finite conductivity become important and further to the near Venus tail where the magnetic tail and plasma sheet are formed. As a result, the structure and dynamics of the induced magnetosphere in both hemispheres occur different. We present different aspects of such an asymmetry and discuss possible mechanisms of its appearance.

  14. The Distribution Function and Transport Properties of Charged Particles in Strong, Crossed Electric and Magnetic fields

    DTIC Science & Technology

    2007-10-11

    kernels of the obtained system of the integro - differential equations . Our work on the project was proceeded during 11 Quarters, the Quarter 12 being...was created to solve a system of the integro - differential equations involv- ing the ion interaction with the electric field as well as the magnetic one...corresponds to the differential (left) side of the Boltzmann equation . When there is not any external force, this operator was studied in [16]. In the presence

  15. Strong geomagnetic activity forecast by neural networks under dominant southern orientation of the interplanetary magnetic field

    NASA Astrophysics Data System (ADS)

    Valach, Fridrich; Bochníček, Josef; Hejda, Pavel; Revallo, Miloš

    2014-02-01

    The paper deals with the relation of the southern orientation of the north-south component Bz of the interplanetary magnetic field to geomagnetic activity (GA) and subsequently a method is suggested of using the found facts to forecast potentially dangerous high GA. We have found that on a day with very high GA hourly averages of Bz with a negative sign occur at least 16 times in typical cases. Since it is very difficult to estimate the orientation of Bz in the immediate vicinity of the Earth one day or even a few days in advance, we have suggested using a neural-network model, which assumes the worse of the possibilities to forecast the danger of high GA - the dominant southern orientation of the interplanetary magnetic field. The input quantities of the proposed model were information about X-ray flares, type II and IV radio bursts as well as information about coronal mass ejections (CME). In comparing the GA forecasts with observations, we obtain values of the Hanssen-Kuiper skill score ranging from 0.463 to 0.727, which are usual values for similar forecasts of space weather. The proposed model provides forecasts of potentially dangerous high geomagnetic activity should the interplanetary CME (ICME), the originator of geomagnetic storms, hit the Earth under the most unfavorable configuration of cosmic magnetic fields. We cannot know in advance whether the unfavorable configuration is going to occur or not; we just know that it will occur with the probability of 31%.

  16. Magnetic-field dependence of strongly anisotropic spin reorientation transition in NdFeO3: a terahertz study.

    PubMed

    Jiang, Junjie; Song, Gaibei; Wang, Dongyang; Jin, Zuanming; Tian, Zhen; Lin, Xian; Han, Jiaguang; Ma, Guohong; Cao, Shixun; Cheng, Zhenxiang

    2016-03-23

    One of the biggest challenges in spintronics is finding how to switch the magnetization of a material. One way of the spin switching is the spin reorientation transition (SRT), a switching of macroscopic magnetization rotated by 90°. The macroscopic magnetization in a NdFeO3 single crystal rotates from Γ4 to Γ2 via Γ24 as the temperature is decreased from 170 to 100 K, while it can be switched back to Γ4 again by increasing the temperature. However, the precise roles of the magnetic-field induced SRT are still unclear. By using terahertz time-domain spectroscopy (THz-TDS), here, we show that the magnetic-field induced SRT between Γ4 and Γ2 is strongly anisotropic, depending on the direction of the applied magnetic field. Our experimental results are well interpreted by the anisotropy of rare-earth Nd(3+) ion. Furthermore, we find that the critical magnetic-field required for SRT can be modified by changing the temperature. Our study suggests that the anisotropic SRT in NdFeO3 single crystal provides a platform to facilitate the potential applications in robust spin memory devices.

  17. Improved ring potential of QED at finite temperature and in the presence of weak and strong magnetic fields

    SciTech Connect

    Sadooghi, N.; Anaraki, K. Sohrabi

    2008-12-15

    Using the general structure of the vacuum polarization tensor {pi}{sub {mu}}{sub {nu}}(k{sub 0},k) in the infrared (IR) limit, k{sub 0}{yields}0, the ring contribution to the QED effective potential at finite temperature and the nonzero magnetic field is determined beyond the static limit, (k{sub 0}{yields}0, k{yields}0). The resulting ring potential is then studied in weak and strong magnetic field limits. In the weak magnetic field limit, at high temperature and for {alpha}{yields}0, the improved ring potential consists of a term proportional to T{sup 4}{alpha}{sup 5/2}, in addition to the expected T{sup 4}{alpha}{sup 3/2} term arising from the static limit. Here, {alpha} is the fine structure constant. In the limit of the strong magnetic field, where QED dynamics is dominated by the lowest Landau level, the ring potential includes a novel term consisting of dilogarithmic function (eB)Li{sub 2}(-(2{alpha}/{pi})(eB/m{sup 2})). Using the ring improved (one-loop) effective potential including the one-loop effective potential and ring potential in the IR limit, the dynamical chiral symmetry breaking of QED is studied at finite temperature and in the presence of the strong magnetic field. The gap equation, the dynamical mass and the critical temperature of QED in the regime of the lowest Landau level dominance are determined in the improved IR as well as in the static limit. For a given value of the magnetic field, the improved ring potential is shown to be more efficient in decreasing the critical temperature arising from the one-loop effective potential.

  18. Magnetic properties of diruthenium(II,III) carboxylate compounds with large zero-field splitting and strong antiferromagnetic coupling.

    PubMed

    Jiménez-Aparicio, R; Urbanos, F A; Arrieta, J M

    2001-02-12

    The magnetic properties of mixed-valent compounds of general formula Ru2Cl(mu-O2CR)4 [R = CH2-CH3 (1), C(Me)=CHEt) (2)] have been studied in the 2-300 K temperature range. This magnetic study also includes a revision of the magnetic properties of the complex Ru2Cl(mu-O2CCMePh2)4 (3). Compounds 1-3 show a linear structure and a strong antiferromagnetic coupling between the diruthenium units through the chlorine atoms according to previous studies. Two fitting models to explain the magnetic properties of these complexes that incorporate a large zero-field splitting together with a strong antiferromagnetic coupling are described. These models consider that each diruthenium unit (S = 3/2) is magnetically coupled to the nearest diruthenium unit and ignores the longer distance magnetic coupling. The fitting models were found to be successful in fitting the magnetic data of the linear diruthenium(II,III) complexes. The zero-field splitting, D, and the antiferromagnetic coupling, zJ, vary from 37.8 to 48.0 cm-1 and from -7.43 to -13.30 cm-1, respectively, for complexes. The D values are similar to those calculated for the nonlinear diruthenium(II,III) compounds and confirm the validity of the proposed fitting models.

  19. Heavy quark diffusion in strong magnetic fields at weak coupling and implications for elliptic flow

    SciTech Connect

    Fukushima, Kenji; Hattori, Koichi; Yee, Ho -Ung; Yin, Yi

    2016-04-20

    In this paper, we compute the momentum diffusion coefficients of heavy quarks, κ and κ, in a strong magnetic field B along the directions parallel and perpendicular to B, respectively, at the leading order in QCD coupling constant αs. We consider a regime relevant for the relativistic heavy ion collisions, αseB << T2 << eB, so that thermal excitations of light quarks are restricted to the lowest Landau level (LLL) states. In the vanishing light-quark mass limit, we find κLO ∝ α2sTeB in the leading order that arises from screened Coulomb scatterings with (1+1)-dimensional LLL quarks, while κ gets no contribution from the scatterings with LLL quarks due to kinematic restrictions. We show that the first nonzero leading order contributions to κLO come from the two separate effects: 1) the screened Coulomb scatterings with thermal gluons, and 2) a finite light-quark mass mq. The former leads to κLO,gluon ∝ α2sT3 and the latter to κLO,massive ∝ αsseB)1/2m2q. Based on our results, we propose a new scenario for the large value of heavy-quark elliptic flow observed in RHIC and LHC. Namely, when κ >> κ, an anisotropy in drag forces gives rise to a sizable amount of the heavy-quark elliptic flow even if heavy quarks do not fully belong to an ellipsoidally expanding background fluid.

  20. Heavy quark diffusion in strong magnetic fields at weak coupling and implications for elliptic flow

    SciTech Connect

    Fukushima, Kenji; Hattori, Koichi; Yee, Ho -Ung; Yin, Yi

    2016-04-20

    In this paper, we compute the momentum diffusion coefficients of heavy quarks, κ and κ, in a strong magnetic field B along the directions parallel and perpendicular to B, respectively, at the leading order in QCD coupling constant αs. We consider a regime relevant for the relativistic heavy ion collisions, αseB << T2 << eB, so that thermal excitations of light quarks are restricted to the lowest Landau level (LLL) states. In the vanishing light-quark mass limit, we find κLO ∝ α2sTeB in the leading order that arises from screened Coulomb scatterings with (1+1)-dimensional LLL quarks, while κ gets no contribution from the scatterings with LLL quarks due to kinematic restrictions. We show that the first nonzero leading order contributions to κLO come from the two separate effects: 1) the screened Coulomb scatterings with thermal gluons, and 2) a finite light-quark mass mq. The former leads to κLO,gluon ∝ α2sT3 and the latter to κLO,massive ∝ αsseB)1/2m2q. Based on our results, we propose a new scenario for the large value of heavy-quark elliptic flow observed in RHIC and LHC. Namely, when κ >> κ, an anisotropy in drag forces gives rise to a sizable amount of the heavy-quark elliptic flow even if heavy quarks do not fully belong to an ellipsoidally expanding background fluid.

  1. Characterizing the response of Juno's JADE-E energy analyzers in the presence of Jupiter's strong magnetic field

    NASA Astrophysics Data System (ADS)

    Clark, G. B.; Allegrini, F.; Crary, F. J.; Louarn, P.; McComas, D. J.; Pollock, C. J.; Valek, P. W.; Weidner, S.

    2011-12-01

    NASA's Juno mission, which is scheduled to launch this August, will be the first spacecraft to achieve polar orbit around Jupiter. The Jovian Auroral Distributions Experiment (JADE), onboard Juno, measures the full pitch angle distribution of electrons (JADE-E) and the 3D velocity-space distribution of ions and ion composition (JADE-I). JADE-E consists of three identical energy analyzers covering the range from ~0.1-100 keV. Below ~5keV and in the relatively strong Jovian magnetic field (up to ~8 G along the orbit) the gyro-radius of electrons is comparable to the radius of curvature of the analyzers. Therefore, the response at low energies will be strongly affected by the magnetic field. To better understand, predict, and correct for the response of JADE-E in the presence of Jupiter's strong magnetic field we are characterizing its response in the laboratory. A set of Helmholtz coils capable of producing a magnetic field up to about 9 G with three axis control was built around the vacuum test chamber. We also compare the laboratory measurements with electro-optics simulations. We will present both simulations and measurement results taken with the engineering model of JADE-E and discuss expected performance of the flight instruments when they arrive at Jupiter.

  2. Strongly magnetized classical plasma models

    NASA Technical Reports Server (NTRS)

    Montgomery, D.; Peyraud, J.; Dewitt, C.

    1974-01-01

    Discrete particle processes in the presence of a strong external magnetic field were investigated. These processes include equations of state and other equilibrium thermodynamic relations, thermal relaxation phenomena, transport properties, and microscopic statistical fluctuations in such quantities as the electric field and the charge density. Results from the equilibrium statistical mechanics of two-dimensional plasmas are discussed, along with nonequilibrium statistical mechanics of the electrostatic guiding-center plasma (a two-dimensional plasma model).

  3. Photon splitting in strong magnetic fields: Asymptotic approximation formulas versus accurate numerical results

    NASA Astrophysics Data System (ADS)

    Wilke, C.; Wunner, G.

    1997-01-01

    We present the results of a numerical calculation of the photon splitting rate below the electron-pair creation threshold (ω<=2m) in magnetic fields B>~Bcr=m2/e=4.414×109 T. Our results confirm asymptotic approximations derived in the low-field (Bfield (B>>Bcr) limit, and allow interpolating between the two asymptotic regions. Our expression for the photon splitting rate is a simplified version of a formula given by Mentzel, Berg, and Wunner. We also point out that, although the analytical formula is correct, the splitting rates calculated there are wrong due to an error in the numerical calculations.

  4. Synchrotron radiation with radiation reaction. [relativistic electron motion in strong astrophysical magnetic fields

    NASA Technical Reports Server (NTRS)

    Nelson, Robert W.; Wasserman, Ira

    1991-01-01

    A rigorous discussion is presented of the classical motion of a relativistic electron in a magnetic field and the resulting electromagnetic radiation when radiation reaction is important. In particular, for an electron injected with initial energy gamma(0), a systematic perturbative solution to the Lorentz-Dirac equation of motion is developed for field strengths satisfying gamma(0) B much less than 6 x 10 to the 15th G. A particularly accurate solution to the electron orbital motion in this regime is found and it is demonstrated how lowest-order corrections can be calculated. It is shown that the total energy-loss rate corresponds to what would be found using the exact Larmor power formula without including radiation reaction. Provided that the particle energy and field strength satisfy the same contraint, it is explicitly demonstrated that the intuitive prescription for calculating the time-integrated radiation spectrum described above is correct.

  5. Analysis of the susceptibility of condensed oxygen under high pressures and in strong magnetic fields

    NASA Astrophysics Data System (ADS)

    Kilit Doğan, E.; Yurtseven, H.

    2017-03-01

    The temperature dependence of the magnetic susceptibility is analyzed at some constant pressures by a power-law formula using the experimental data from the literature for the α - β and β - γ transitions in oxygen. A weak discontinuous (nearly continuous) transition occurring from the α to the β phase, becomes more discontinuous (weakly first order) for the β - γ transition as observed experimentally, which can be explained in terms of the critical exponents deduced from our analysis. The magnetic field dependence of the differential susceptibility is also analyzed in this study for the α -O2 at 4.2 K by a power-law formula using the experimental data. λ-type of observed behaviour of the differential susceptibility is discussed in terms of our analysis for the α -O2 .

  6. Fast torsional waves and strong magnetic field within the Earth's core.

    PubMed

    Gillet, Nicolas; Jault, Dominique; Canet, Elisabeth; Fournier, Alexandre

    2010-05-06

    The magnetic field inside the Earth's fluid and electrically conducting outer core cannot be directly probed. The root-mean-squared (r.m.s.) intensity for the resolved part of the radial magnetic field at the core-mantle boundary is 0.3 mT, but further assumptions are needed to infer the strength of the field inside the core. Recent diagnostics obtained from numerical geodynamo models indicate that the magnitude of the dipole field at the surface of a fluid dynamo is about ten times weaker than the r.m.s. field strength in its interior, which would yield an intensity of the order of several millitesla within the Earth's core. However, a 60-year signal found in the variation in the length of day has long been associated with magneto-hydrodynamic torsional waves carried by a much weaker internal field. According to these studies, the r.m.s. strength of the field in the cylindrical radial direction (calculated for all length scales) is only 0.2 mT, a figure even smaller than the r.m.s. strength of the large-scale (spherical harmonic degree n field visible at the core-mantle boundary. Here we reconcile numerical geodynamo models with studies of geostrophic motions in the Earth's core that rely on geomagnetic data. From an ensemble inversion of core flow models, we find a torsional wave recurring every six years, the angular momentum of which accounts well for both the phase and the amplitude of the six-year signal for change in length of day detected over the second half of the twentieth century. It takes about four years for the wave to propagate throughout the fluid outer core, and this travel time translates into a slowness for Alfvén waves that corresponds to a r.m.s. field strength in the cylindrical radial direction of approximately 2 mT. Assuming isotropy, this yields a r.m.s. field strength of 4 mT inside the Earth's core.

  7. Comprehensive kinetic analysis of the plasma-wall transition layer in a strongly tilted magnetic field

    SciTech Connect

    Tskhakaya, D. D.; Kos, L.

    2014-10-15

    The magnetized plasma-wall transition (MPWT) layer at the presence of the obliquity of the magnetic field to the wall consists of three sub-layers: the Debye sheath (DS), the magnetic pre-sheath (MPS), and the collisional pre-sheath (CPS) with characteristic lengths λ{sub D} (electron Debye length), ρ{sub i} (ion gyro-radius), and ℓ (the smallest relevant collision length), respectively. Tokamak plasmas are usually assumed to have the ordering λ{sub D}≪ρ{sub i}≪ℓ, when the above-mentioned sub-layers can be distinctly distinguished. In the limits of ε{sub Dm}(λ{sub D}/ρ{sub i})→0 and ε{sub mc}(ρ{sub i}/ℓ)→0 (“asymptotic three-scale (A3S) limits”), these sub-layers are precisely defined. Using the smallness of the tilting angle of the magnetic field to the wall, the ion distribution functions are found for three sub-regions in the analytic form. The equations and characteristic length-scales governing the transition (intermediate) regions between the neighboring sub-layers (CPS – MPS and MPS – DS) are derived, allowing to avoid the singularities arising from the ε{sub Dm}→0 and ε{sub mc}→0 approximations. The MPS entrance and the related kinetic form of the Bohm–Chodura condition are successfully defined for the first time. At the DS entrance, the Bohm condition maintains its usual form. The results encourage further study and understanding of physics of the MPWT layers in the modern plasma facilities.

  8. Investigation of a nonequilibrium polariton condensate in cylindrical micropillars in a strong magnetic field

    NASA Astrophysics Data System (ADS)

    Brichkin, A. S.; Novikov, S. I.; Chernenko, A. V.; Schneider, C.; Hoefling, S.

    2017-05-01

    We analyze the photoluminescence of a nonequilibrium polariton condensate in cylindrical micropillars etched on the surface of a high-Q GaAs microcavity in a wide range of detunings in a magnetic field up to 12 T for various levels of nonresonant laser pumping by nanosecond pulses. With such a method of excitation, a considerable effect of the interaction of the reservoir of photoexcited excitons with the condensate on the Zeeman splitting of the polariton condensate levels can be expected, which can lead to a decrease in its value and even to sign reversal. However, the measurements of photoluminescence in a wide range of optical excitation densities show that Zeeman splitting weakly depends on the optical pumping (its variation does not exceed 15% of the splitting in a field of 12 T). The estimation of the exciton density in the reservoir based on these data gives a value lower than 108 cm-2. In addition, a noticeable decrease (by a factor of about 1.8) in the polariton condensation threshold in a magnetic field is detected.

  9. Turbulence in the Outer Regions of Protoplanetary Disks. II. Strong Accretion Driven by a Vertical Magnetic Field

    NASA Astrophysics Data System (ADS)

    Simon, Jacob B.; Bai, Xue-Ning; Armitage, Philip J.; Stone, James M.; Beckwith, Kris

    2013-09-01

    We carry out a series of local, vertically stratified shearing box simulations of protoplanetary disks that include ambipolar diffusion and a net vertical magnetic field. The ambipolar diffusion profiles we employ correspond to 30 AU and 100 AU in a minimum mass solar nebula (MMSN) disk model, which consists of a far-ultraviolet-ionized surface layer and low-ionization disk interior. These simulations serve as a follow-up to Simon et al., in which we found that without a net vertical field, the turbulent stresses that result from the magnetorotational instability (MRI) are too weak to account for observed accretion rates. The simulations in this work show a very strong dependence of the accretion stresses on the strength of the background vertical field; as the field strength increases, the stress amplitude increases. For a net vertical field strength (quantified by β0, the ratio of gas to magnetic pressure at the disk mid-plane) of β0 = 104 and β0 = 105, we find accretion rates \\dot{M} \\sim 10^{-8}-10-7 M ⊙ yr-1. These accretion rates agree with observational constraints, suggesting a vertical magnetic field strength of ~60-200 μG and 10-30 μG at 30 AU and 100 AU, respectively, in a MMSN disk. Furthermore, the stress has a non-negligible component due to a magnetic wind. For sufficiently strong vertical field strengths, MRI turbulence is quenched, and the flow becomes largely laminar, with accretion proceeding through large-scale correlations in the radial and toroidal field components as well as through the magnetic wind. In all simulations, the presence of a low-ionization region near the disk mid-plane, which we call the ambipolar damping zone, results in reduced stresses there.

  10. Flow of a Two-Dimensional Liquid Metal Jet in a Strong Magnetic Field

    NASA Astrophysics Data System (ADS)

    Molokov, S.; Reed, C. B.

    2002-01-01

    A combined effect of surface tension, gravity, inertia and a transverse nonuniform magnetic field on the steady, two-dimensional jet (or curtain) flow is studied with reference to liquid metal divertors of tokamaks and coating flows. Here main fundamental aspects of the flow are presented. More details on the assumptions, analysis and results are given in. Consider a steady flow of a viscous, electrically conducting, incompressible fluid in a jet pouring downward in the x-asterisk-direction (the direction of gravity) from a nozzle.

  11. Numerical and exact density functional studies of light atoms in strong magnetic fields

    NASA Astrophysics Data System (ADS)

    Zhu, Wuming

    2005-11-01

    Although current density functional theory (CDFT) was proposed almost two decades ago, rather little progress has been made in development and application of this theory, in contrast to many successful applications that ordinary density functional theory (DFT) has enjoyed. In parallel with early DFT exploration, we have made extensive studies on atom-like systems in an external magnetic field. The objectives are to advance our comparative understanding of the DFT and CDFT descriptions of such systems. A subsidiary objective is to provide extensive data on light atoms in high fields, notably those of astrophysical interest. To address the cylindrical symmetry induced by the external field, an efficient, systematic way to construct high quality basis sets within anisotropic Gaussians is provided. Using such basis sets, we did extensive Hartree-Fock and DFT calculations on helium through carbon atoms in a wide range of B fields. The applicability and limitations of modern DFT and CDFT functionals for atomic systems in such fields is analyzed. An exact soluble two-electron model system, Hooke's atom (HA), is studied in detail. Analogously with known results for zero field, we developed exact analytical solutions for some specific confinement and field strengths. Exact DFT and CDFT quantities for the HA in B fields, specifically exchange and correlation functionals were obtained and compared with results from approximate functionals. Major qualitative differences were identified. A major overall conclusion of the work is that the vorticity variable, introduced in CDFT to ensure gauge invariance, is rather difficult to handle computationally. The difficulty is severe enough to suggest that it might be profitable to seek an alternative gauge-invariance formulation of the current-dependence in DFT.

  12. Generation of disc-like plasma from laser-matter interaction in the presence of a strong external magnetic field

    DOE PAGES

    Ivanov, V. V.; Maximov, A. V.; Betti, R.; ...

    2017-05-16

    Dynamics of laser produced plasma in a strong magnetic field was studied here using a 1 MA pulsed power generator coupled to an intense, high-energy laser. A 2–2.5 MG magnetic field was generated on the surface of a rod load 0.8–1.2 mm in diameter. A sub-nanosecond laser pulse with intensity of 3 × 1015 W cm-2 was focused on the rod load surface. Side-on laser diagnostics showed the generation of two collimated jets 1–3 mm long on the front and rear sides of the load. End-on laser diagnostics reveal that the laser produced plasma in the MG magnetic field takesmore » the form of a thin disc as the plasma propagates along the magnetic field lines. The disc-like plasma expands radially across the magnetic field with a velocity of 250 km s-1. An electron temperature of 400 eV was measured in the laser-produced plasma on the rod load.« less

  13. Generation of disc-like plasma from laser-matter interaction in the presence of a strong external magnetic field

    NASA Astrophysics Data System (ADS)

    Ivanov, V. V.; Maximov, A. V.; Betti, R.; Wiewior, P. P.; Hakel, P.; Sherrill, M. E.

    2017-08-01

    Dynamics of laser produced plasma in a strong magnetic field was studied using a 1 MA pulsed power generator coupled to an intense, high-energy laser. A 2-2.5 MG magnetic field was generated on the surface of a rod load 0.8-1.2 mm in diameter. A sub-nanosecond laser pulse with intensity of 3 × 1015 W cm-2 was focused on the rod load surface. Side-on laser diagnostics showed the generation of two collimated jets 1-3 mm long on the front and rear sides of the load. End-on laser diagnostics reveal that the laser produced plasma in the MG magnetic field takes the form of a thin disc as the plasma propagates along the magnetic field lines. The disc-like plasma expands radially across the magnetic field with a velocity of 250 km s-1. An electron temperature of 400 eV was measured in the laser-produced plasma on the rod load.

  14. Monodomain dynamics for rigid rod and platelet suspensions in strongly coupled coplanar linear flow and magnetic fields. II. Kinetic theory

    NASA Astrophysics Data System (ADS)

    Forest, M. Gregory; Sircar, Sarthok; Wang, Qi; Zhou, Ruhai

    2006-10-01

    We establish reciprocity relations of the Doi-Hess kinetic theory for rigid rod macromolecular suspensions governed by the strong coupling among an excluded volume potential, linear flow, and a magnetic field. The relation provides a reduction of the flow and field driven Smoluchowski equation: from five parameters for coplanar linear flows and magnetic field, to two field parameters. The reduced model distinguishes flows with a rotational component, which map to simple shear (with rate parameter) subject to a transverse magnetic field (with strength parameter), and irrotational flows, for which the reduced model consists of a triaxial extensional flow (with two extensional rate parameters). We solve the Smoluchowski equation of the reduced model to explore: (i) the effect of introducing a coplanar magnetic field on each sheared monodomain attractor of the Doi-Hess kinetic theory and (ii) the coupling of coplanar extensional flow and magnetic fields. For (i), we show each sheared attractor (steady and unsteady, with peak axis in and out of the shearing plane, periodic and chaotic orbits) undergoes its own transition sequence versus magnetic field strength. Nonetheless, robust predictions emerge: out-of-plane degrees of freedom are arrested with increasing field strength, and a unique flow-aligning or tumbling/wagging limit cycle emerges above a threshold magnetic field strength or modified geometry parameter value. For (ii), irrotational flows coupled with a coplanar magnetic field yield only steady states. We characterize all (generically biaxial) equilibria in terms of an explicit Boltzmann distribution, providing a natural generalization of analytical results on pure nematic equilibria [P. Constantin, I. Kevrekidis, and E. S. Titi, Arch. Rat. Mech. Anal. 174, 365 (2004); P. Constantin, I. Kevrekidis, and E. S. Titi, Discrete and Continuous Dynamical Systems 11, 101 (2004); P. Constantin and J. Vukadinovic, Nonlinearity 18, 441 (2005); H. Liu, H. Zhang, and P

  15. Hot electromagnetic outflows. III. Displaced fireball in a strong magnetic field

    SciTech Connect

    Thompson, Christopher; Gill, Ramandeep

    2014-08-10

    The evolution of a dilute electron-positron fireball is calculated in the regime of strong magnetization and high compactness (ℓ ∼ 10{sup 3}-10{sup 8}). Heating is applied at a low effective temperature (<25 keV), appropriate to breakout from a confining medium, so that relaxation to a blackbody is inhibited by pair annihilation. The diffusion equation for Compton scattering by thermal pairs is coupled to a trans-relativistic cyclo-synchrotron source. We find that the photon spectrum develops a quasi-thermal peak at energy ∼0.1 m{sub e}c {sup 2} in the comoving frame, with a power-law slope below it that is characteristic of gamma-ray bursts (GRBs; F{sub ω} ∼ const). The formation of a thermal high-energy spectrum is checked using the full kinetic equations. Calculations for a baryon-dominated photosphere reveal a lower spectral peak energy, and a harder low-energy spectrum, unless ion rest mass carries ≲ 10{sup –5} of the energy flux. We infer that (1) the GRB spectrum is inconsistent with the neutron-rich wind emitted by a young magnetar or neutron torus, and points to an event horizon in the engine; (2) neutrons play a negligible role in prompt gamma-ray emission; (3) the relation between observed peak frequency and burst energy is bounded below by the observed Amati relation if the Lorentz factor ∼(opening angle){sup –1} at breakout, and the jet is surrounded by a broader sheath that interacts with a collapsing stellar core; (4) X-ray flashes are consistent with magnetized jets with ion-dominated photospheres; (5) high-frequency Alfvén waves may become charge starved in the dilute pair gas; (6) limitations on magnetic reconnection from plasma collisionality have been overestimated.

  16. Thomas-Fermi and Thomas-Fermi-Dirac models in two-dimension - Effect of strong quantizing magnetic field

    NASA Astrophysics Data System (ADS)

    De, Sanchari; Chakrabarty, Somenath

    2017-01-01

    Using Thomas-Fermi (TF) and Thomas-Fermi-Dirac (TFD) models, we have investigated the properties of electron gas inside two-dimensional (2D) Wigner-Seitz (WS) cells in presence of a strong orthogonal quantizing magnetic field. The electron-electron Coulomb exchange interaction in quasi-2D case is obtained. The exact form of exchange term in 2D is derived making the width of the system tending to zero. Further, using the exchange term, the Thomas-Fermi-Dirac equation in 2D is established. It has been observed that only the ionized WS cell can have finite radius in the Thomas-Fermi model, even in presence of a strong quantizing magnetic field. On the other hand, in the Thomas-Fermi-Dirac model a neutral WS cell can have finite radius.

  17. Effects of a Strong Static Magnetic Field on Bacterium Shewanellaoneidensis: An Assessment by Using Whole Genome Microarray.

    SciTech Connect

    Gao, W.; Liu, Y.; Zhou, J.-Z.; Hongjun, P.

    2007-04-02

    The effect of a strong static 14.1 T magnetic field on logphase cells of bacterial strain Shewanella oneidensis MR-1 was evaluatedby using whole genome microarray of this bacterium. Although differenceswere not observed between the treatment and control by measuring theoptical density (OD), colony forming unit (CFU), as well as post-exposuregrowth of cells, transcriptional expression levels of 65 genes werealtered according to our microarray data. Among these genes, 21 wereupregulated while other 44were downregulated, compared withcontrol.

  18. FTIR investigation of the effects of ultra-strong static magnetic field on the secondary structures of protein in bacteria

    NASA Astrophysics Data System (ADS)

    She, Zichao; Hu, Xing; Zhao, Xusheng; Ren, Zhongming; Ding, Guoji

    2009-07-01

    Secondary structures of protein in Escherichia coli ( E. coli) and Staphylococcus aureus ( S. aureus) exposed to the ultra-strong static magnetic field (SMF) were investigated by Fourier transformation infrared spectroscopy (FTIR). Difference index D value of amide I (1600-1700 cm -1) showed that the ultra-strong magnetic field had little impact on S. aureus, but had strong impact on E. coli. The results indicated that 3.46-9.92% of the disorder coils in the secondary structures of protein in E. coli were turned into α-helices under SMF while applying deconvolution and curve fitting to amide I. At the same time, intermolecular β-sheets transforming into intramolecular ones suggested that cohesion among protein molecules had been destroyed and intramolecular hydrogen bonds strengthened. All the differences among the compositions of protein's secondary structures in E. coli were mostly due to the varying degrees of various proteins affected by the magnetic field. The results may provide new insights into the structural changes of proteins induced by the SMF.

  19. Strong Magnetic Field Fluctuations within Filamentary Auroral Density Cavities Interpreted as VLF Saucer Sources

    NASA Technical Reports Server (NTRS)

    Knudsen, D. L.; Kabirzadeh, R.; Burchill, J. K.; Pfaff, Robert F.; Wallis, D. D.; Bounds, S. R.; Clemmons, J. H.; Pincon, J.-L.

    2012-01-01

    The Geoelectrodynamics and Electro-Optical Detection of Electron and SuprathermalIon Currents (GEODESIC) sounding rocket encountered more than 100 filamentary densitycavities associated with enhanced plasma waves at ELF (3 kHz) and VLF (310 kHz)frequencies and at altitudes of 800990 km during an auroral substorm. These cavities weresimilar in size (20 m diameter in most cases) to so-called lower-hybrid cavities (LHCs)observed by previous sounding rockets and satellites; however, in contrast, many of theGEODESIC cavities exhibited up to tenfold enhancements in magnetic wave powerthroughout the VLF band. GEODESIC also observed enhancements of ELF and VLFelectric fields both parallel and perpendicular to the geomagnetic field B0 within cavities,though the VLF E field increases were often not as large proportionally as seen in themagnetic fields. This behavior is opposite to that predicted by previously published theoriesof LHCs based on passive scattering of externally incident auroral hiss. We argue thatthe GEODESIC cavities are active wave generation sites capable of radiating VLF wavesinto the surrounding plasma and producing VLF saucers, with energy supplied by cold,upward flowing electron beams composing the auroral return current. This interpretation issupported by the observation that the most intense waves, both inside and outside cavities,occurred in regions where energetic electron precipitation was largely inhibited orabsent altogether. We suggest that the wave-enhanced cavities encountered by GEODESICwere qualitatively different from those observed by earlier spacecraft because of thefortuitous timing of the GEODESIC launch, which placed the payload at apogee within asubstorm-related return current during its most intense phase, lasting only a few minutes.

  20. Microgravity simulation by diamagnetic levitation: effects of a strong gradient magnetic field on the transcriptional profile of Drosophila melanogaster.

    PubMed

    Herranz, Raul; Larkin, Oliver J; Dijkstra, Camelia E; Hill, Richard J A; Anthony, Paul; Davey, Michael R; Eaves, Laurence; van Loon, Jack J W A; Medina, F Javier; Marco, Roberto

    2012-02-01

    Many biological systems respond to the presence or absence of gravity. Since experiments performed in space are expensive and can only be undertaken infrequently, Earth-based simulation techniques are used to investigate the biological response to weightlessness. A high gradient magnetic field can be used to levitate a biological organism so that its net weight is zero. We have used a superconducting magnet to assess the effect of diamagnetic levitation on the fruit fly D. melanogaster in levitation experiments that proceeded for up to 22 consecutive days. We have compared the results with those of similar experiments performed in another paradigm for microgravity simulation, the Random Positioning Machine (RPM). We observed a delay in the development of the fruit flies from embryo to adult. Microarray analysis indicated changes in overall gene expression of imagoes that developed from larvae under diamagnetic levitation, and also under simulated hypergravity conditions. Significant changes were observed in the expression of immune-, stress-, and temperature-response genes. For example, several heat shock proteins were affected. We also found that a strong magnetic field, of 16.5 Tesla, had a significant effect on the expression of these genes, independent of the effects associated with magnetically-induced levitation and hypergravity. Diamagnetic levitation can be used to simulate an altered effective gravity environment in which gene expression is tuned differentially in diverse Drosophila melanogaster populations including those of different age and gender. Exposure to the magnetic field per se induced similar, but weaker, changes in gene expression.

  1. Strongly Magnetized Accretion Disks Around Black Holes

    NASA Astrophysics Data System (ADS)

    Salvesen, Greg; Armitage, Philip J.; Simon, Jacob B.; Begelman, Mitchell C.

    2017-01-01

    Recent observations are suggestive of strongly magnetized accretion disks around black holes. Performing local (shearing box) simulations of accretion disks, we investigate how a strong magnetization state can develop and persist. We demonstrate that poloidal flux is a necessary prerequisite for the sustainability of strongly magnetized accretion disks. We also show that black hole spin measurements can become unconstrained if magnetic fields provide a significant contribution to the vertical pressure support of the accretion disk atmosphere.

  2. Longitudinal and transverse spin diffusion in3He-4He solutions in a strong magnetic field

    NASA Astrophysics Data System (ADS)

    Ager, J. H.; Child, A.; König, R.; Owers-Bradley, J. R.; Bowley, R. M.

    1995-06-01

    Using pulsed NMR techniques, we have measured spin diffusion in3He-3He solutions with3He concentrations of 0.05%, 0.1%, 0.46%, 1.0%, 3.8% and 6.4% in a magnetic field of 8.8 Tesla for a temperature range 11 mK⩽ T ⩽ 200 mK. We observe that the temperature dependence of the transverse spin diffusion coefficient D1 deviates from that expected for an unpolarized Fermi liquid in the degenerate region in the 1.0%, 3.8% and 6.4% solutions. Moreover, by measuring both longitudinal and transverse spin diffusion coefficients in the 6.4%-mixture, we have verified experimentally the difference between them, and provided direct evidence for a field-induced anisotropy in spin diffusion. The results from the 0.05% and 0.1% solutions show agreement with the theory of Jeon and Mullin; however, no deviation of D1 from that expected in an unpolarized mixture was observed because the3He is not in the degenerate regime for these very dilute systems for the temperatures we could achieve. The analysis of our measurements in terms of the Leggett-Rice equations also yields values for the spin rotation parameter μM0. Using our results along with previous measurements at various3He concentrations, we deduce a value for the s-wave quasiparticle scattering length of a=-0.88 ± 0.05 Å.

  3. Hydrogen atom in a strong magnetic field. II. Relativistic corrections for low-lying excited states

    NASA Astrophysics Data System (ADS)

    Poszwa, A.; Rutkowski, A.

    2004-02-01

    The highly accurate solution of the Schrödinger equation in the form of common Landau exponential factor multiplied by a power series in two variables, the sine of the cone angle and radial variable is completed by the first-order relativistic correction calculated within the framework of the relativistic direct perturbation theory (DPT). It is found that in contrast to behavior of relativistic corrections for the ground state and 2p-1(ms=-1/2) excited state, which change sign from negative to positive near B≈1011 G and B≈1010 G, respectively [Z. Chen and S. P. Goldman, Phys. Rev A 45, 1722 (1992)], the relativistic corrections for 2s0(ms=-1/2) and 2p0(ms=-1/2) excited states are negative for the magnetic field varying in range 0field-free states with principal quantum numbers n=2,3,4 are presented.

  4. Energetics and dynamics of resonant and nonresonant scattering in strong magnetic fields

    NASA Technical Reports Server (NTRS)

    Lamb, Don Q.; Wang, John C. L.; Wasserman, Ira M.

    1990-01-01

    The energetics and the dynamics resulting from electron-photon resonant and nonresonant scattering in a plasma with magnetic field about 10 to the 12th G are studied in detail. Precise analytic results are obtained in the optically thin limit, and numerical results are presented for the optically thick case. For the latter, it is found that when the equilibrium temperature T(C) is determined by the cooling/heating balance due solely to cyclotron resonant scattering, the ratio of T(C) to the superstrong field B remains fairly constant for N(e) up to about 6 x 10 to the 21st electrons/sq cm. This line-dominated region comes to an end when the extra heating from the hard continuum photons becomes competitive with the line processes and drives T(C) well above the pure line value. For parameters characteristic of GB 880205, the thickness of the line-dominated region is determined to be between 10 to the 21st and 10 to the 22nd electrons/sq cm.

  5. MAGNETIC RECONNECTION TURBULENCE IN STRONG GUIDE FIELDS: BASIC PROPERTIES AND APPLICATION TO CORONAL HEATING

    SciTech Connect

    Pueschel, M. J.; Terry, P. W.; Zweibel, E. G.; Zhdankin, V.; Told, D.; Jenko, F.; Lesch, H.

    2014-08-01

    A current sheet susceptible to the tearing instability is used to drive reconnection turbulence in the presence of a strong guide field. Through nonlinear gyrokinetic simulations, the dependencies of central quantities such as the heating rate on parameters like collisionality or plasma β are studied, revealing that linear physics tends to predict only some aspects of the quasi-saturated state, with the nonlinear cascade responsible for additional features. For the solar corona, it is demonstrated that the kinetic heating associated with this type of turbulence agrees quantitatively with observational volumetric heating rates. In the context of short particle acceleration events, the self-consistent emergence of plasmoids or flux ropes in the turbulent bath is found to be important: ubiquitously occurring merger events of these objects cause strong bursts in the heating rate, the timescale of which is consistent with nanoflare observations. Furthermore, anisotropy of the temperature fluctuations is seen to emerge, hinting at a new means of generating coronal ion temperature anisotropy in the absence of cyclotron resonances.

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

    SciTech Connect

    Coelho, Eduardo L.; Chiapparini, Marcelo; Bracco, Mirian E.

    2013-03-25

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

  7. The magnetoresonance operation of microwiggler on the piezoelectrics with a strong magnetic guide field

    SciTech Connect

    Choi, J.S.; So, C.H.; Moon, J.D.

    1995-12-31

    We proposed that a new type of the electrostatic microwiggler with a wiggler period (0.1 mm {le}1{sub w}{le}1 mm) and the wiggler field strength (E{sub w}{le} 100 kV/m) can be produced on the surface of a PZT when a high power and high frequency ultrasonic wave travels through a PZT bar. Numerical simulations in the linear and nonlinear gain regime show that a weak microwiggler (E{sub w}100 kV/m,{lambda}{sub w}{approx}100 periods), operating in magnetoresonance with a strong guide field (B{sub o}{approx} 3.6T), can generate a millimeter and submillimeter radiations with medium electronic efficiency of few percents. It is shown that the maximum output power of the compact FEL using the wiggler system generated on the surface of the piezoelectric material may be upto a few Watts with a relatively low energy and low current electron beam (Ew {approx}100 keV and I{sub b}1 mA).

  8. A Drift-Asymptotic scheme for a fluid description of plasmas in strong magnetic fields

    NASA Astrophysics Data System (ADS)

    Deluzet, Fabrice; Ottaviani, Maurizio; Possanner, Stefan

    2017-10-01

    We present a numerical scheme for the ion Euler equations with Braginskii closure, in the quasi-neutral regime with an adiabatic electron response. The scheme is constructed with the aid of asymptotic-preserving (AP) techniques in order to avoid the singularity in the drift-limit. When the normalized gyro-radius tends to zero, the scheme performs the drift-limit numerically. Depending on the choice of the time step, it can resolve different physical phenomena, ranging from cyclotron motion to plasma transport or ion drifts. Since the development of AP-schemes for the Braginskii equations is in its exploratory phase, the plasma is assumed a three-dimensional slab in a uniform external magnetic field. We use the ion-temperature-gradient dispersion relation for the scheme's verification. The promising results show that the method offers the possibility to adapt the numerical parameters to the desired resolution in the full fluid model, instead of switching to reduced models in the drift-limit.

  9. Creation of electron-positron pairs at excited Landau levels by neutrino in a strong magnetic field

    NASA Astrophysics Data System (ADS)

    Kuznetsov, A. V.; Rumyantsev, D. A.; Savin, V. N.

    2014-10-01

    The process of neutrino production of electron-positron pairs in a magnetic field of arbitrary strength, where electrons and positrons can be created in the states corresponding to excited Landau levels, is analyzed. The mean value of the neutrino energy loss due to the process ν → νe-e+ is calculated. The result can be applied for calculating the efficiency of the electron-positron plasma production by neutrinos in the conditions of the Kerr black hole accretion disk considered by experts as the most possible source of a short cosmological gamma burst. The presented research can also be useful for further development of the calculation technique for an analysis of quantum processes in external active medium, and in part in the conditions of moderately strong magnetic field, when taking account of the ground Landau level appears to be insufficient.

  10. Analytical GIAO and hybrid-basis integral derivatives: application to geometry optimization of molecules in strong magnetic fields.

    PubMed

    Tellgren, Erik I; Reine, Simen S; Helgaker, Trygve

    2012-07-14

    Analytical integral evaluation is a central task of modern quantum chemistry. Here we present a general method for evaluating differentiated integrals over standard Gaussian and mixed Gaussian/plane-wave hybrid orbitals. The main idea is to have a representation of basis sets that is flexible enough to enable differentiated integrals to be reinterpreted as standard integrals over modified basis functions. As an illustration of the method, we report a very simple implementation of Hartree-Fock level geometrical derivatives in finite magnetic fields for gauge-origin independent atomic orbitals, within the London program. As a quantum-chemical application, we optimize the structure of helium clusters and some well-known covalently bound molecules (water, ammonia and benzene) subject to strong magnetic fields.

  11. Spontaneous Electromagnetic Superconductivity of Vacuum in a Strong Magnetic Field: Evidence from the Nambu-Jona-Lasinio Model

    NASA Astrophysics Data System (ADS)

    Chernodub, M. N.

    2011-04-01

    Using an extended Nambu-Jona-Lasinio model as a low-energy effective model of QCD, we show that the vacuum in a strong external magnetic field (stronger than 1016T) experiences a spontaneous phase transition to an electromagnetically superconducting state. The unexpected superconductivity of, basically, empty space is induced by emergence of quark-antiquark vector condensates with quantum numbers of electrically charged rho mesons. The superconducting phase possesses an anisotropic inhomogeneous structure similar to a periodic Abrikosov lattice in a type-II superconductor. The superconducting vacuum is made of a new type of vortices which are topological defects in the charged vector condensates. The superconductivity is realized along the axis of the magnetic field only. We argue that this effect is absent in pure QED.

  12. Spontaneous electromagnetic superconductivity of vacuum in a strong magnetic field: evidence from the Nambu-Jona-Lasinio model.

    PubMed

    Chernodub, M N

    2011-04-08

    Using an extended Nambu-Jona-Lasinio model as a low-energy effective model of QCD, we show that the vacuum in a strong external magnetic field (stronger than 10(16)   T) experiences a spontaneous phase transition to an electromagnetically superconducting state. The unexpected superconductivity of, basically, empty space is induced by emergence of quark-antiquark vector condensates with quantum numbers of electrically charged rho mesons. The superconducting phase possesses an anisotropic inhomogeneous structure similar to a periodic Abrikosov lattice in a type-II superconductor. The superconducting vacuum is made of a new type of vortices which are topological defects in the charged vector condensates. The superconductivity is realized along the axis of the magnetic field only. We argue that this effect is absent in pure QED.

  13. Stable perfectly matched layers for a cold plasma in a strong background magnetic field

    NASA Astrophysics Data System (ADS)

    Bécache, Eliane; Joly, Patrick; Kachanovska, Maryna

    2017-07-01

    This work addresses the question of the construction of stable perfectly matched layers (PMLs) for a cold plasma in the infinitely large background magnetic field. We demonstrate that the traditional, Bérenger's perfectly matched layers are unstable when applied to this model, due to the presence of the backward propagating waves. To overcome this instability, we use a combination of two techniques presented in the article. First of all, we consider a simplified 2D model, which shares with the 3D case one of the difficulties for the PML treatment, namely, the presence of the backward propagating waves. Based on the fact that for a fixed frequency either forward or backward propagating waves are present, we stabilize the PMLs with the help of a frequency-dependent correction. An extra difficulty of the 3D model compared to the 2D case is the presence of both forward and backward waves for a fixed frequency. To overcome this problem we construct a system of equations that consists of two independent systems, which are equivalent to the original model. The first of the systems behaves like the 2D plasma model, and hence the PMLs are stabilized again with the help of the frequency-dependent correction. The second system resembles the Maxwell equations in vacuum, and hence the standard Bérenger's PMLs are stable for it. The systems are solved inside the perfectly matched layer, and coupled to the original Maxwell equations, which are solved in a physical domain, on a discrete level through an artificial layer. The numerical experiments confirm the stability of the new technique.

  14. Scalar and spinor particles with low binding energy in a strong stationary magnetic field in two and three dimensions

    SciTech Connect

    Rodionov, V. N.

    2007-06-15

    We discuss the equations for the bound one-active electron states based on analytic solutions of the Schroedinger and Pauli equations for a uniform magnetic field and a single attractive {delta}(r) potential. It is very important that the electron ground states in a magnetic field differ essentially from the analogous state of spin-0 particles, whose binding energy was intensively studied more than forty years ago. We show that the binding-energy equations for spin-1/2 particles can be obtained without using the language of boundary conditions in the {delta}-potential model developed in the pioneering works. We use the obtained equations to calculate the energy level displacements analytically and to demonstrate nonlinear dependences on the field intensity. We show that the magnetic field indeed plays a stabilizing role in the considered systems in the case of weak intensity, but the opposite occurs in the case of strong intensity. These properties may be important for real quantum mechanical fermionic systems in two and three dimensions.

  15. Strong Solar Wind Dynamic Pressure Pulses during Solar Cycle 23 and Their Impacts on Geosynchronous Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Zuo, P.

    2015-12-01

    Solar wind dynamic pressure pulse (DPP) structures, across which the dynamic pressure abruptly changes over timescales from a few seconds to several minutes, are often observed in the near-Earth space environment. In this investigation, we first present a statistical study on the properties of strong dynamic pressure pulses in the solar wind during solar cycle 23. It is found that overwhelming majority of DPPs are associated with the solar wind disturbances including the CME-related flows, the corotating interaction regions, as well as the complex ejecta. The annual variations of the averaged occurrence rate of DPPs are roughly in phase with the solar activities. Although the variabilities of geosynchronous magnetic fields (GMFs) due to the impact of positive DPPs have been well established, there appears no systematic investigations on the response of GMFs to negative DPPs. Here we also study the decompression/compression effects of very strong negative/positive DPPs on GMFs under northward IMFs. In response to the decompression of strong negative DPPs, GMFs on dayside, near the dawn and dusk on nightside are generally depressed. But near the midnight region, the responses of GMF are very diverse, being either positive or negative. For part of events when GOES is located at the midnight sector, GMF is found to abnormally increase as the result of magnetospheric decompression caused by negative DPPs. It is known that on certain conditions magnetic depression of nightside GMFs can be caused by the impact of positive DPPs. Here we found that, a stronger pressure enhancement may have a higher probability of producing the exceptional depression of GMF at midnight region. Statistically, both the decompression effect of strong negative DPPs and the compression effect of strong positive DPPs depend on the magnetic local time, being stronger at the noon sector.

  16. Formulation of the twisted-light-matter interaction at the phase singularity: Beams with strong magnetic fields

    NASA Astrophysics Data System (ADS)

    Quinteiro, G. F.; Reiter, D. E.; Kuhn, T.

    2017-01-01

    The formulation of the interaction of matter with singular light fields needs special care. In a recent article [G. F. Quinteiro et al., Phys. Rev. A 91, 033808 (2015), 10.1103/PhysRevA.91.033808] we have shown that the Hamiltonian describing the interaction of a twisted-light beam having parallel orbital and spin angular momenta with a small object located close to the phase singularity can be expressed only in terms of the electric field of the beam. Here we complement our study by providing an interaction Hamiltonian for beams having antiparallel orbital and spin angular momenta. Such beams may exhibit unusually strong magnetic effects. We further extend our formulation to radially and azimuthally polarized beams. The advantages of our formulation are that for all beams the Hamiltonian is written solely in terms of the electric and magnetic fields of the beam and as such it is manifestly gauge invariant. Furthermore, it is intuitive by resembling the well-known expressions in the dipole-electric and dipole-magnetic moment approximations.

  17. Microgravity simulation by diamagnetic levitation: effects of a strong gradient magnetic field on the transcriptional profile of Drosophila melanogaster

    PubMed Central

    2012-01-01

    Background Many biological systems respond to the presence or absence of gravity. Since experiments performed in space are expensive and can only be undertaken infrequently, Earth-based simulation techniques are used to investigate the biological response to weightlessness. A high gradient magnetic field can be used to levitate a biological organism so that its net weight is zero. Results We have used a superconducting magnet to assess the effect of diamagnetic levitation on the fruit fly D. melanogaster in levitation experiments that proceeded for up to 22 consecutive days. We have compared the results with those of similar experiments performed in another paradigm for microgravity simulation, the Random Positioning Machine (RPM). We observed a delay in the development of the fruit flies from embryo to adult. Microarray analysis indicated changes in overall gene expression of imagoes that developed from larvae under diamagnetic levitation, and also under simulated hypergravity conditions. Significant changes were observed in the expression of immune-, stress-, and temperature-response genes. For example, several heat shock proteins were affected. We also found that a strong magnetic field, of 16.5 Tesla, had a significant effect on the expression of these genes, independent of the effects associated with magnetically-induced levitation and hypergravity. Conclusions Diamagnetic levitation can be used to simulate an altered effective gravity environment in which gene expression is tuned differentially in diverse Drosophila melanogaster populations including those of different age and gender. Exposure to the magnetic field per se induced similar, but weaker, changes in gene expression. PMID:22296880

  18. He 2++ molecular ion in a strong time-dependent magnetic field: a current-density functional study.

    PubMed

    Vikas

    2011-08-01

    The He 2++ molecular ion exposed to a strong ultrashort time-dependent (TD) magnetic field of the order of 10(9) G is investigated through a quantum fluid dynamics (QFD) and current-density functional theory (CDFT) based approach using vector exchange-correlation (XC) potential and energy density functional that depend not only on the electronic charge-density but also on the current density. The TD-QFD-CDFT computations are performed in a parallel internuclear-axis and magnetic field-axis configuration at the field-free equilibrium internuclear separation R = 1.3 au with the field-strength varying between 0 and 10(11) G. The TD behavior of the exchange- and correlation energy of the He 2++ is analyzed and compared with that obtained using a [B-TD-QFD-density functional theory (DFT)] approach based on the conventional TD-DFT under similar computational constraints but using only scalar XC potential and energy density functional dependent on the electronic charge-density alone. The CDFT based approach yields TD exchange- and correlation energy and TD electronic charge-density significantly different from that obtained using the conventional TD-DFT based approach, particularly, at typical magnetic field strengths and during a typical time period of the TD field. This peculiar behavior of the CDFT-based approach is traced to the TD current-density dependent vector XC potential, which can induce nonadiabatic effects causing retardation of the oscillating electronic charge density. Such dissipative electron dynamics of the He 2++ molecular ion is elucidated by treating electronic charge density as an electron-"fluid" in the terminology of QFD. Copyright © 2011 Wiley Periodicals, Inc.

  19. Second-order magnetic field gradient-induced strong coupling between nitrogen-vacancy centers and a mechanical oscillator

    NASA Astrophysics Data System (ADS)

    Cai, Kang; Wang, RuiXia; Yin, ZhangQi; Long, GuiLu

    2017-07-01

    We consider a cantilever mechanical oscillator (MO) made of diamond. A nitrogen-vacancy (NV) center lies at the end of the cantilever. Two magnetic tips near the NV center induce a strong second-order magnetic field gradient. Under coherent driving of the MO, we find that the coupling between the MO and the NV center is greatly enhanced. We studied how to generate entanglement between the MO and the NV center and realize quantum state transfer between them. We also propose a scheme to generate two-mode squeezing between different MO modes by coupling them to the same NV center. The decoherence and dissipation effects for both the MO and the NV center are numerically calculated using the present parameter values of the experimental configuration. We have achieved high fidelity for entanglement generation, quantum state transfer, and large two-mode squeezing.

  20. High-latitude dayside electric fields and currents during strong northward interplanetary magnetic field - Observations and model simulation

    NASA Technical Reports Server (NTRS)

    Clauer, C. Robert; Friis-Christensen, Eigil

    1988-01-01

    On July 23, 1983 the IMF turned strongly northward, becoming about 22 nT for several hours. Using a combined data set of ionospheric convection measurements made by the Sondre Stromfjord incoherent scatter radar and convection inferred from Greenland magnetometer measurements, the onset of the reconfiguration of the high-latitude ionospheric currents is found to occur about 3 min after the northward IMF encounters the magnetopause. The large-scale reconfiguration of currents, however, appears to evolve over a period of about 22 min. These observations and the results of numerical simulations indicate that the dayside polar-cap electric field observed during strong northward IMF is produced by a direct electrical current coupling with the solar wind.

  1. High-latitude dayside electric fields and currents during strong northward interplanetary magnetic field - Observations and model simulation

    NASA Technical Reports Server (NTRS)

    Clauer, C. Robert; Friis-Christensen, Eigil

    1988-01-01

    On July 23, 1983 the IMF turned strongly northward, becoming about 22 nT for several hours. Using a combined data set of ionospheric convection measurements made by the Sondre Stromfjord incoherent scatter radar and convection inferred from Greenland magnetometer measurements, the onset of the reconfiguration of the high-latitude ionospheric currents is found to occur about 3 min after the northward IMF encounters the magnetopause. The large-scale reconfiguration of currents, however, appears to evolve over a period of about 22 min. These observations and the results of numerical simulations indicate that the dayside polar-cap electric field observed during strong northward IMF is produced by a direct electrical current coupling with the solar wind.

  2. Phase transitions of dense neutron matter with generalized Skyrme interaction to superfluid states with triplet pairing in strong magnetic field

    NASA Astrophysics Data System (ADS)

    Tarasov, A. N.

    2012-12-01

    A generalized non-relativistic Fermi-liquid approach was used to find analytical formulas for temperatures Tc1(n, H) and Tc2(n, H) (which are functions nonlinear of density n and linear of magnetic field H) of phase transitions in spatially uniform dense pure neutron matter from normal to superfluid states with spin-triplet p-wave pairing (similar to anisotropic superfluid phases 3He-A1 and 3He-A2) in steady and homogeneous strong magnetic field (but |μn| H ll Ec < ɛF(n), where μn is the magnetic dipole moment of a neutron, Ec is the cutoff energy and ɛF(n) is the Fermi energy in neutron matter). General formulas for Tc1, 2 (n, H) (valid for arbitrary parameterization of the effective Skyrme interaction in neutron matter) are specified here for generalized BSk18 parameterization of the Skyrme forces (with additional terms dependent on density n) on the interval 0.3 n0 < n < nc (BSk18) ≍ 2.7952 · n0, where n0 = 0.17 fm-3 is nuclear density and at critical density nc(BSk18) triplet superfluidity disappears, Tc0(n, cH = 0) = 0. Expressions for phase transition temperatures Tc0(n)<0.09MeV (at Ec = 10MeV) and Tc1, 2(n, H) are realistic non-monotone functions of density n for BSk18 parameterization of the Skyrme forces (contrary to their monotone increase for all previous BSk parameterizations). Phase transitions to superfluid states of such type might occur in liquid outer core of magnetars (strongly magnetized neutron stars).

  3. Enhanced betatron radiation in strongly magnetized plasma

    SciTech Connect

    Pan, K. Q.; Zheng, C. Y. He, X. T.; Cao, L. H.; Liu, Z. J.

    2016-04-15

    Betatron radiation in strongly magnetized plasma is investigated by two dimensional (2D) particle-in-cell (PIC) simulations. The results show that the betatron radiation in magnetized plasmas is strongly enhanced and is more collimated compared to that in unmagnetized plasma. Single particle model analysis shows that the frequency and the amplitude of the electrons's betatron oscillation are strongly influenced by the axial external magnetic field and the axial self-generated magnetic field. And the 2D PIC simulation shows that the axial magnetic field is actually induced by the external magnetic field and tends to increase the betatron frequency. By disturbing the perturbation of the plasma density in the laser-produced channel, the hosing instability is also suppressed, which results in a better angular distribution and a better symmetry of the betatron radiation.

  4. Dynamics of large-scale instabilities in conductors electrically exploded in strong magnetic fields

    NASA Astrophysics Data System (ADS)

    Datsko, I. M.; Chaikovsky, S. A.; Labetskaya, N. A.; Oreshkin, V. I.; Ratakhin, N. A.

    2014-11-01

    The growth of large-scale instabilities during the propagation of a nonlinear magnetic diffusion wave through a conductor was studied experimentally. The experiment was carried out using the MIG terawatt pulsed power generator at a peak current up to 2.5 MA with 100 ns rise time. It was observed that instabilities with a wavelength of 150 μm developed on the surface of the conductor hollow part within 160 ns after the onset of current flow, whereas the surface of the solid rod remained almost unperturbed. A system of equations describing the propagation of a nonlinear diffusion wave through a conductor and the growth of thermal instabilities has been solved numerically. It has been revealed that the development of large- scale instabilities is obviously related to the propagation of a nonlinear magnetic diffusion wave.

  5. Weak Broadband Electromagnetic Fields are More Disruptive to Magnetic Compass Orientation in a Night-Migratory Songbird (Erithacus rubecula) than Strong Narrow-Band Fields.

    PubMed

    Schwarze, Susanne; Schneider, Nils-Lasse; Reichl, Thomas; Dreyer, David; Lefeldt, Nele; Engels, Svenja; Baker, Neville; Hore, P J; Mouritsen, Henrik

    2016-01-01

    Magnetic compass orientation in night-migratory songbirds is embedded in the visual system and seems to be based on a light-dependent radical pair mechanism. Recent findings suggest that both broadband electromagnetic fields ranging from ~2 kHz to ~9 MHz and narrow-band fields at the so-called Larmor frequency for a free electron in the Earth's magnetic field can disrupt this mechanism. However, due to local magnetic fields generated by nuclear spins, effects specific to the Larmor frequency are difficult to understand considering that the primary sensory molecule should be organic and probably a protein. We therefore constructed a purpose-built laboratory and tested the orientation capabilities of European robins in an electromagnetically silent environment, under the specific influence of four different oscillating narrow-band electromagnetic fields, at the Larmor frequency, double the Larmor frequency, 1.315 MHz or 50 Hz, and in the presence of broadband electromagnetic noise covering the range from ~2 kHz to ~9 MHz. Our results indicated that the magnetic compass orientation of European robins could not be disrupted by any of the relatively strong narrow-band electromagnetic fields employed here, but that the weak broadband field very efficiently disrupted their orientation.

  6. Weak Broadband Electromagnetic Fields are More Disruptive to Magnetic Compass Orientation in a Night-Migratory Songbird (Erithacus rubecula) than Strong Narrow-Band Fields

    PubMed Central

    Schwarze, Susanne; Schneider, Nils-Lasse; Reichl, Thomas; Dreyer, David; Lefeldt, Nele; Engels, Svenja; Baker, Neville; Hore, P. J.; Mouritsen, Henrik

    2016-01-01

    Magnetic compass orientation in night-migratory songbirds is embedded in the visual system and seems to be based on a light-dependent radical pair mechanism. Recent findings suggest that both broadband electromagnetic fields ranging from ~2 kHz to ~9 MHz and narrow-band fields at the so-called Larmor frequency for a free electron in the Earth’s magnetic field can disrupt this mechanism. However, due to local magnetic fields generated by nuclear spins, effects specific to the Larmor frequency are difficult to understand considering that the primary sensory molecule should be organic and probably a protein. We therefore constructed a purpose-built laboratory and tested the orientation capabilities of European robins in an electromagnetically silent environment, under the specific influence of four different oscillating narrow-band electromagnetic fields, at the Larmor frequency, double the Larmor frequency, 1.315 MHz or 50 Hz, and in the presence of broadband electromagnetic noise covering the range from ~2 kHz to ~9 MHz. Our results indicated that the magnetic compass orientation of European robins could not be disrupted by any of the relatively strong narrow-band electromagnetic fields employed here, but that the weak broadband field very efficiently disrupted their orientation. PMID:27047356

  7. Strong coupling operation of a free-electron-laser amplifier with an axial magnetic field

    NASA Astrophysics Data System (ADS)

    Rullier, J. L.; Devin, A.; Gardelle, J.; Labrouche, J.; Le Taillandier, P.; Donohue, J. T.

    1996-03-01

    We present the results of a free-electron-laser (FEL) experiment at 35 GHz, using a strongly relativistic electron beam (T=1.75 MeV). The electron pulse length is 30 ns full width at half maximum with a peak current of 400 A. The FEL is designed to operate in the high-gain Compton regime, with a negative coupling parameter (Φ<0) leading to a strong growth rate. More than 50 MW of rf power in the TE11 mode (43 dB gain) has been obtained with good reproducibility. The experimental results are in good agreement with predictions made using the three-dimensional stationary simulation code solitude.

  8. Strongly magnetized accretion discs require poloidal flux

    NASA Astrophysics Data System (ADS)

    Salvesen, Greg; Armitage, Philip J.; Simon, Jacob B.; Begelman, Mitchell C.

    2016-08-01

    Motivated by indirect observational evidence for strongly magnetized accretion discs around black holes, and the novel theoretical properties of such solutions, we investigate how a strong magnetization state can develop and persist. To this end, we perform local simulations of accretion discs with an initially purely toroidal magnetic field of equipartition strength. We demonstrate that discs with zero net vertical magnetic flux and realistic boundary conditions cannot sustain a strong toroidal field. However, a magnetic pressure-dominated disc can form from an initial configuration with a sufficient amount of net vertical flux and realistic boundary conditions. Our results suggest that poloidal flux is a necessary prerequisite for the sustainability of strongly magnetized accretion discs.

  9. Quark magnetar in three-flavor Nambu-Jona-Lasinio model under strong magnetic fields with two types of vector interactions

    NASA Astrophysics Data System (ADS)

    Chu, Peng-Cheng; Wang, Bin; Jia, Yu-Yue; Dong, Yu-Min; Wang, Shu-Mei; Li, Xiao-Hua; Zhang, Lei; Zhang, Xiao-Min; Ma, Hong-Yang

    2016-12-01

    We investigate the properties of strange quark matter (SQM) and quark stars (QSs) in the framework of SU(3) Nambu-Jona-Lasinio (NJL) model with two types of vector interactions under strong magnetic fields: (1) the flavor-dependent repulsion among u , d , and s quarks with the coupling constant GV, and (2) the universal repulsion and the vector-isovector interaction with the coupling constants gV and GI V. The effects of the two types of vector interactions on the constituent quark mass, vacuum quark mass, quark chemical potential, and quark fraction in SQM under strong magnetic fields are studied, and the results indicate that these physical quantities for SQM are all sensitive to the two types of vector interactions in NJL model under magnetic fields. Using a density-dependent magnetic field profile which is introduced to describe the magnetic field strength distribution inside the magnetars, we calculate the properties of spherical QSs by using two extreme cases for the orientation of the magnetic field inside the stars, i.e., the radial orientation in which the magnetic fields are along the radial direction in stars, and the transverse orientation in which the magnetic fields are randomly oriented in the plane which is perpendicular to the radial direction. Our results indicate that the maximum mass of QSs may dependent on both the strength distribution and the orientation of the magnetic fields inside QSs by using SU(3) NJL model.

  10. Tunable High-Field Magnetization in Strongly Exchange-Coupled Freestanding Co/CoO Core/Shell Coaxial Nanowires.

    PubMed

    Salazar-Alvarez, German; Geshev, Julian; Agramunt-Puig, Sebastià; Navau, Carles; Sanchez, Alvaro; Sort, Jordi; Nogués, Josep

    2016-08-31

    The exchange bias properties of Co/CoO coaxial core/shell nanowires were investigated with cooling and applied fields perpendicular to the wire axis. This configuration leads to unexpected exchange-bias effects. First, the magnetization value at high fields is found to depend on the field-cooling conditions. This effect arises from the competition between the magnetic anisotropy and the Zeeman energies for cooling fields perpendicular to the wire axis. This allows imprinting predefined magnetization states to the antiferromagnetic (AFM) shell, as corroborated by micromagnetic simulations. Second, the system exhibits a high-field magnetic irreversibility, leading to open hysteresis loops attributed to the AFM easy axis reorientation during the reversal (effect similar to athermal training). A distinct way to manipulate the high-field magnetization in exchange-biased systems, beyond the archetypical effects, was thus experimentally and theoretically demonstrated.

  11. Quasilongitudinal soliton in a two-dimensional strongly coupled complex dusty plasma in the presence of an external magnetic field.

    PubMed

    Ghosh, Samiran

    2014-09-01

    The propagation of a nonlinear low-frequency mode in two-dimensional (2D) monolayer hexagonal dusty plasma crystal in presence of external magnetic field and dust-neutral collision is investigated. The standard perturbative approach leads to a 2D Korteweg-de Vries (KdV) soliton for the well-known dust-lattice mode. However, the Coriolis force due to crystal rotation and Lorentz force due to magnetic field on dust particles introduce a linear forcing term, whereas dust-neutral drag introduce the usual damping term in the 2D KdV equation. This new nonlinear equation is solved both analytically and numerically to show the competition between the linear forcing and damping in the formation of quasilongitudinal soliton in a 2D strongly coupled complex (dusty) plasma. Numerical simulation on the basis of the typical experimental plasma parameters and the analytical solution reveal that the neutral drag force is responsible for the usual exponential decay of the soliton, whereas Coriolis and/or Lorentz force is responsible for the algebraic decay as well as the oscillating tail formation of the soliton. The results are discussed in the context of the plasma crystal experiment.

  12. Quasilongitudinal soliton in a two-dimensional strongly coupled complex dusty plasma in the presence of an external magnetic field

    NASA Astrophysics Data System (ADS)

    Ghosh, Samiran

    2014-09-01

    The propagation of a nonlinear low-frequency mode in two-dimensional (2D) monolayer hexagonal dusty plasma crystal in presence of external magnetic field and dust-neutral collision is investigated. The standard perturbative approach leads to a 2D Korteweg-de Vries (KdV) soliton for the well-known dust-lattice mode. However, the Coriolis force due to crystal rotation and Lorentz force due to magnetic field on dust particles introduce a linear forcing term, whereas dust-neutral drag introduce the usual damping term in the 2D KdV equation. This new nonlinear equation is solved both analytically and numerically to show the competition between the linear forcing and damping in the formation of quasilongitudinal soliton in a 2D strongly coupled complex (dusty) plasma. Numerical simulation on the basis of the typical experimental plasma parameters and the analytical solution reveal that the neutral drag force is responsible for the usual exponential decay of the soliton, whereas Coriolis and/or Lorentz force is responsible for the algebraic decay as well as the oscillating tail formation of the soliton. The results are discussed in the context of the plasma crystal experiment.

  13. Two-dimensional cavity polaritons under the influence of the perpendicular strong magnetic and electric fields. The gyrotropy effects

    NASA Astrophysics Data System (ADS)

    Moskalenko, S. A.; Podlesny, I. V.; Dumanov, E. V.; Liberman, M. A.

    2015-11-01

    The properties of the two-dimensional cavity polaritons subjected to the action of a strong perpendicular magnetic and electric fields, giving rise to the Landau quantization (LQ) of the 2D electrons and holes accompanied by the Rashba spin-orbit coupling, by the Zeeman splitting and by the nonparabolicity of the heavy-hole dispersion law are investigated. We use the method proposed by Rashba (1960) [1] and the obtained results are based on the exact solutions for the eigenfunctions and for the eigenvalues of the Pauli-type Hamilonians with third order chirality terms and nonparabolic dispersion law for heavy-holes and with the first order chirality terms for electrons. The selection rules of the band-to-band optical quantum transitions as well as of the quantum transitions from the ground state of the crystal to the magnetoexciton states depend essentially on the numbers ne and nh of the LQ levels of the (e-h) pair forming the magnetoexciton. It is shown that the Rabi frequency ΩR of the polariton branches and the magnetoexciton oscillator strength fosc increase with the magnetic field strength B as ΩR √{ B }, and fosc B. The optical gyrotropy effects may be revealed changing the sign of the photon circular polarization at a given sign of the wave vector longitudinal projection kz or equivalently changing the sign of kz at the same selected circular polarization.

  14. Description of transport mechanisms in a very long wave infrared quantum cascade detector under strong magnetic field

    NASA Astrophysics Data System (ADS)

    Jasnot, François-Régis; Maëro, Simon; Péré-Laperne, Nicolas; de Vaulchier, Louis-Anne; Guldner, Yves; Carosella, Francesca; Ferreira, Robson; Delga, Alexandre; Doyennette, Laetitia; Berger, Vincent; Trinité, Virginie; Carras, Mathieu

    2012-12-01

    Measurements of current have been performed on a very long wave infrared quantum cascade detector under strong magnetic field applied parallel to the growth axis, both under dark and light conditions. The analysis of dark current as a function of temperature highlights three regimes of transport involving the different energy levels of the structure. For photocurrent analysis, we developed a model based on a rate equation approach taking into account all the electronic levels of the structure. This model is in agreement with the oscillatory component of the experimental magnetophotocurrent. It allows to identify the key points controlling the electronic transport such as extraction from the upper level of the optically active quantum well, location of ionized impurities, and scattering mechanisms involved in the structure. This work is valuable for the future conception of high-performance quantum cascade detectors in infrared and far infrared range.

  15. a Dedicated Beam Tests of the Full-Scale Prototype of GEMS for Cms in a Strong Magnetic Field

    NASA Astrophysics Data System (ADS)

    Abbaneo, D.; Bally, S.; Postema, H.; Garcia, A. Conde; Chatalain, J. P.; Faber, G.; Ropelewski, L.; Pinto, S. Duarte; Croci, G.; Alfonsi, M.; van Stenis, M.; Sharma, A.; Villa, M.; Zientek, M.; Benussi, L.; Bianco, S.; Colafranceschi, S.; Fabbri, F.; Passamonti, L.; Piccolo, D.; Pierluigi, D.; Raffone, G.; Russo, A.; Saviano, G.; Marinov, A.; Tytgat, M.; Zaganidis, N.; Hohlmann, M.; Gnanvo, K.; Bagliesi, M. G.; Cecchi, R.; Turini, N.; Oliveri, E.; Magazzu, G.

    2012-08-01

    In the high-eta (1.6 - 2.4) region of the CMS endcap, Gas Electron Multipliers (GEM) present an interesting option for a future upgrade of the forward region of the CMS muon system. Large GEM detectors are challenging due to technological issues; in the view of the CMS upgrade we have designed and built the largest full-size triple GEM-based muon detector to-date. This prototype meets the stringent requirements of the hostile forward environment of CMS at high-luminosity LHC. Dedicated test beam measurements have been performed at the SPS in June 2011 to study efficiency, space resolution, and timing performance with different inter-electrode gap configurations and gas mixtures and in a strong magnetic field of 3T (as at CMS). Preliminary results of these experimental tests will be presented.

  16. B fields in OB stars (BOB): Detection of a magnetic field in the He-strong star CPD -57° 3509

    NASA Astrophysics Data System (ADS)

    Przybilla, N.; Fossati, L.; Hubrig, S.; Nieva, M.-F.; Järvinen, S. P.; Castro, N.; Schöller, M.; Ilyin, I.; Butler, K.; Schneider, F. R. N.; Oskinova, L. M.; Morel, T.; Langer, N.; de Koter, A.; BOB Collaboration

    2016-03-01

    Aims: We report the detection of a magnetic field in the helium-strong star CPD -57° 3509 (B2 IV), a member of the Galactic open cluster NGC 3293, and characterise the star's atmospheric and fundamental parameters. Methods: Spectropolarimetric observations with FORS2 and HARPSpol are analysed using two independent approaches to quantify the magnetic field strength. A high-S/N FLAMES/GIRAFFE spectrum is analysed using a hybrid non-LTE model atmosphere technique. Comparison with stellar evolution models constrains the fundamental parameters of the star. Results: We obtain a firm detection of a surface averaged longitudinal magnetic field with a maximum amplitude of about 1 kG. Assuming a dipolar configuration of the magnetic field, this implies a dipolar field strength larger than 3.3 kG. Moreover, the large amplitude and fast variation (within about 1 day) of the longitudinal magnetic field implies that CPD -57° 3509 is spinning very fast despite its apparently slow projected rotational velocity. The star should be able to support a centrifugal magnetosphere, yet the spectrum shows no sign of magnetically confined material; in particular, emission in Hα is not observed. Apparently, the wind is either not strong enough for enough material to accumulate in the magnetosphere to become observable or, alternatively, some leakage process leads to loss of material from the magnetosphere. The quantitative spectroscopic analysis of the star yields an effective temperature and a logarithmic surface gravity of 23 750 ± 250 K and 4.05 ± 0.10, respectively, and a surface helium fraction of 0.28 ± 0.02 by number. The surface abundances of C, N, O, Ne, S, and Ar are compatible with the cosmic abundance standard, whereas Mg, Al, Si, and Fe are depleted by about a factor of 2. This abundance pattern can be understood as the consequence of a fractionated stellar wind. CPD -57° 3509 is one of the most evolved He-strong stars known with an independent age constraint due to its

  17. Behavior of Particle Depots in Molten Silicon During Float-Zone Growth in Strong Static Magnetic Fields

    NASA Technical Reports Server (NTRS)

    Jauss, T.; SorgenFrei, T.; Croell, A.; Azizi, M.; Reimann, C.; Friedrich, J.; Volz, M. P.

    2014-01-01

    In the photovoltaics industry, the largest market share is represented by solar cells made from multicrystalline silicon, which is grown by directional solidification. During the growth process, the silicon melt is in contact with the silicon nitride coated crucible walls and the furnace atmosphere which contains carbon monoxide. The dissolution of the crucible coating, the carbon bearing gas, and the carbon already present in the feedstock, lead to the precipitation of silicon carbide, and silicon nitride, at later stages of the growth process. The precipitation of Si3N4 and SiC particles of up to several hundred micrometers in diameter leads to severe problems during the wire sawing process for wafering the ingots. Furthermore the growth of the silicon grains can be negatively influenced by the presence of particles, which act as nucleation sources and lead to a grit structure of small grains and are sources for dislocations. If doped with Nitrogen from the dissolved crucible coating, SiC is a semi conductive material, and can act as a shunt, short circuiting parts of the solar cell. For these reasons, the incorporation of such particles needs to be avoided. In this contribution we performed model experiments in which the transport of intentionally added SiC particles and their interaction with the solid-liquid interface during float zone growth of silicon in strong steady magnetic fields was investigated. SiC particles of 7µm and 60µm size are placed in single crystal silicon [100] and [111] rods of 8mm diameter. This is achieved by drilling a hole of 2mm diameter, filling in the particles and closing the hole by melting the surface of the rod until a film of silicon covers the hole. The samples are processed under a vacuum of 1x10(exp -5) mbar or better, to prevent gas inclusions. An oxide layer to suppress Marangoni convection is applied by wet oxidation. Experiments without and with static magnetic field are carried out to investigate the influence of melt

  18. Moderate and strong static magnetic fields directly affect EGFR kinase domain orientation to inhibit cancer cell proliferation

    PubMed Central

    Wang, Wenchao; Li, Zhiyuan; Liu, Juanjuan; Yang, Xingxing; Ji, Xinmiao; Luo, Yan; Hu, Chen; Hou, Yubin; He, Qianqian; Fang, Jun; Wang, Junfeng; Liu, Qingsong; Li, Guohui; Lu, Qingyou; Zhang, Xin

    2016-01-01

    Static magnetic fields (SMFs) can affect cell proliferation in a cell-type and intensity-dependent way but the mechanism remains unclear. At the same time, although the diamagnetic anisotropy of proteins has been proposed decades ago, the behavior of isolated proteins in magnetic fields has not been directly observed. Here we show that SMFs can affect isolated proteins at the single molecular level in an intensity-dependent manner. We found that Epidermal Growth Factor Receptor (EGFR), a protein that is overexpressed and highly activated in multiple cancers, can be directly inhibited by SMFs. Using Liquid-phase Scanning Tunneling Microscopy (STM) to examine pure EGFR kinase domain proteins at the single molecule level in solution, we observed orientation changes of these proteins in response to SMFs. This may interrupt inter-molecular interactions between EGFR monomers, which are critical for their activation. In molecular dynamics (MD) simulations, 1-9T SMFs caused increased probability of EGFR in parallel with the magnetic field direction in an intensity-dependent manner. A superconducting ultrastrong 9T magnet reduced proliferation of CHO-EGFR cells (Chinese Hamster Ovary cells with EGFR overexpression) and EGFR-expressing cancer cell lines by ~35%, but minimally affected CHO cells. We predict that similar effects of magnetic fields can also be applied to some other proteins such as ion channels. Our paper will help clarify some dilemmas in this field and encourage further investigations in order to achieve a better understanding of the biological effects of SMFs. PMID:27223425

  19. HELIOSPHERIC ASYMMETRIES AND 2-3 kHz RADIO EMISSION UNDER STRONG INTERSTELLAR MAGNETIC FIELD CONDITIONS

    SciTech Connect

    Pogorelov, Nikolai V.; Heerikhuisen, Jacob; Zank, Gary P.; Mitchell, Jeremy J.; Cairns, Iver H.

    2009-04-10

    We discuss the asymmetry of the major heliospheric discontinuities obtained from the analysis of three-dimensional modeling of the solar wind interaction with the local interstellar medium (LISM). The flow of charged particles is governed by the ideal MHD equations and the transport of neutral particles is described by the Boltzmann equation. The emphasis is on the asymmetries of the termination shock (TS) and the heliopause under the combined action of the interstellar and interplanetary magnetic fields (ISMF and IMF) in the presence of neutral hydrogen atoms. It is shown that an ISMF of a strength greater than 4 {mu}G can account for the 10 AU difference in the TS heliocentric distances observed by the Voyager 1 and Voyager 2 spacecraft. We analyze the deflection of neutral hydrogen flow from its original direction in the unperturbed LISM and conclude that it remains within the range measured in the SOHO SWAN experiment. The impact is analyzed of a strong ISMF on the 2-3 kHz radio emission observed by the Voyager spacecraft, using new estimates of the radio emission conditions.

  20. SUPER STRONG MAGNETIC FIELDS OF NEUTRON STARS IN BE X-RAY BINARIES ESTIMATED WITH NEW TORQUE AND MAGNETOSPHERE MODELS

    SciTech Connect

    Shi, Chang-Sheng; Zhang, Shuang-Nan; Li, Xiang-Dong

    2015-11-10

    We re-estimate the surface magnetic fields of neutron stars (NSs) in Be X-ray binaries (BeXBs) with different models of torque, improved beyond Klus et al. In particular, a new torque model is applied to three models of magnetosphere radius. Unlike the previous models, the new torque model does not lead to divergent results for any fastness parameter. The inferred surface magnetic fields of these NSs for the two compressed magnetosphere models are much higher than that for the uncompressed magnetosphere model. The new torque model using the compressed magnetosphere radius leads to unique solutions near spin equilibrium in all cases, unlike other models that usually give two branches of solutions. Although our conclusions are still affected by the simplistic assumptions about the magnetosphere radius calculations, we show several groups of possible surface magnetic field values with our new models when the interaction between the magnetosphere and the infalling accretion plasma is considered. The estimated surface magnetic fields for NSs BeXBs in the Large Magellanic Cloud, the Small Magellanic Cloud and the Milk Way are between the quantum critical field and the maximum “virial” value by the spin equilibrium condition.

  1. Investigation of magnetospheric processes with the use of a source of strong magnetic field in the ionosphere

    NASA Astrophysics Data System (ADS)

    Biriukov, A. S.; Veselovskii, I. S.; Grigorian, O. R.; Koval', A. D.; Kuznetsov, S. N.; Kropotkin, A. P.; Panasiuk, M. I.; Riabukha, S. B.; Us, A. A.; Shuvalov, V. A.

    1992-12-01

    Attention is given to a spacecraft-based experiment examining the structure of a local formation such as an artificial 'magnetosphere' and the processes occurring in it, and the effects arising in the interaction of the moving magnetosphere with the ionospheric plasma. The corresponding space scales of this 'magnetosphere' are about 10 m in the experiment with relatively small magnets in the ionosphere and about 100 m in the solar wind. The corresponding similarity criteria are estimated. The possible scheme of the experiment with a superconducting magnet installed aboard the satellite is considered. The experimental complex includes a number of systems for measuring the fluxes of charged particles in a wide energy range, dc electric and magnetic fields, and the electromagnetic fields in different frequency bands.

  2. The Zeeman effect in astrophysical water masers and the observation of strong magnetic fields in regions of star formation

    NASA Technical Reports Server (NTRS)

    Nedoluha, Gerald E.; Watson, William D.

    1992-01-01

    The present study solves the transfer equations for the polarized radiation of astrophysical 22-GHz water masers in the presence of a magnetic field which causes a Zeeman splitting that is much smaller than the spectral line breadth. The emphasis is placed on the relationship between the recently detected circular polarization in this maser radiation and the strength of the magnetic field. When the observed spectral line breadth is smaller than about 0.8 km/s (FWHM), it is calculated that the uncertainty is less than a factor of about 2. The accuracy is improved significantly when the angle between the line of sight and the direction of the magnetic field does not exceed about 45 deg. Uncertainty in the strength of the magnetic field due to lack of knowledge about which hyperfine transition is the source of the 22-GHz masers is removed. The 22-GHz maser feature is found to be the result of a merger of the three strongest hyperfine components.

  3. Magnetic field generator

    DOEpatents

    Krienin, Frank

    1990-01-01

    A magnetic field generating device provides a useful magnetic field within a specific retgion, while keeping nearby surrounding regions virtually field free. By placing an appropriate current density along a flux line of the source, the stray field effects of the generator may be contained. One current carrying structure may support a truncated cosine distribution, and it may be surrounded by a current structure which follows a flux line that would occur in a full coaxial double cosine distribution. Strong magnetic fields may be generated and contained using superconducting cables to approximate required current surfaces.

  4. Strong transverse fields in delta-spots

    NASA Technical Reports Server (NTRS)

    Zirin, Harold; Wang, Haimin

    1993-01-01

    Spectroscopic measurements of the strength and direction of transverse magnetic fields in six delta-spots are presented. The field direction is determined by the relative strength of the pi- and sigma-components at different polarizer orientations, and is, with one exception, parallel to the neutral line and as strong as the umbral field. Field strengths determined by line splitting are as high as 3980 G.

  5. Strong transverse fields in delta-spots

    NASA Technical Reports Server (NTRS)

    Zirin, Harold; Wang, Haimin

    1993-01-01

    Spectroscopic measurements of the strength and direction of transverse magnetic fields in six delta-spots are presented. The field direction is determined by the relative strength of the pi- and sigma-components at different polarizer orientations, and is, with one exception, parallel to the neutral line and as strong as the umbral field. Field strengths determined by line splitting are as high as 3980 G.

  6. Explicitly-correlated non-born-oppenheimer calculations of the HD molecule in a strong magnetic field

    NASA Astrophysics Data System (ADS)

    Adamowicz, Ludwik; Stanke, Monika; Tellgren, Erik; Helgaker, Trygve

    2017-08-01

    Explicitly correlated all-particle Gaussian functions with shifted centers (ECGs) are implemented within the earlier proposed effective variational non-Born-Oppenheimer method for calculating bound states of molecular systems in magnetic field (Adamowicz et al., 2015). The Hamiltonian used in the calculations is obtained by subtracting the operator representing the kinetic energy of the center-of-mass motion from the total laboratory-frame Hamiltonian. Test ECG calculations are performed for the HD molecule.

  7. Induced quadrupole effects near a crossover in a tetragonal TbLiF{sub 4} sheelite in a strong magnetic field up to 50 T

    SciTech Connect

    Kazei, Z. A. Snegirev, V. V.; Broto, J.-M.; Abdulsabirov, R. Yu.; Korableva, S. L.

    2012-12-15

    The anomalies of magnetic properties of TbLiF{sub 4} caused by the interaction of the energy levels of a rare-earth ion in a strong magnetic field up to 50 T directed along the [100] and [110] axes are studied experimentally and theoretically. The jumps in magnetization M(H) and the maxima of the differential magnetic susceptibility dM(H)/dH are found in critical fields H{sub c} = 28 and 31 T, where the lower component of the excited doublet approaches the ground-state singlet of a Tb{sup 3+} ion. Based on the crystal-field model with known interaction parameters, we calculated the Zeeman effect and the magnetization and magnetic susceptibility curves for the TbLiF{sub 4} crystal, which adequately describe magnetic anomalies and critical parameters of a crossover. It is shown that the jumpwise change in the {alpha}- and {gamma}-symmetry quadrupole interactions in TbLiF{sub 4} caused by changes in the corresponding quadrupole moments during the crossing of energy levels leads, in accordance with experiments, to a decrease in the critical field H{sub c} by approximately 4 T and an increase in the maximum of the differential susceptibility dM(H)/dH near the crossover more than twofold. This behavior can be considered as an analog of the induced quadrupole transition caused by a change of the ground state of the rare-earth ion during crossover.

  8. Effect of a strong, DC-induced magnetic field on circadian singing activity of the house cricket (orthoptera:gryllidae)

    SciTech Connect

    Shaw, K.C.; Bitzer, R.J.; Galliart, L.

    1995-05-01

    We investigated the effect of a strong, DC-induced electromagnetic field (EMF) on the circadian singing activity of the house cricket, Acheta domesticus (L.). Groups of 10 crickets were exposed to strong, DC-induced EMFs under two light regimes, 12:12 (L:D) h and 0:24 (L:D) h. Exposure to the strong EMF resulted in an increase in mean time per hour during which one or more crickets were singing and in number of crickets singing per hour. Correcting for phase shift during O:24 (L:D) h, the daily pattern of singing was apparently unaffected by any treatment. The greatest percentage of singing and number of crickets singing per hour occurred during actual or expected scotophase. This is the first report of an increase in insect activity during exposure to a strong DC-induced EMF.

  9. Quantum fluid dynamics based current-density functional study of a helium atom in a strong time-dependent magnetic field

    NASA Astrophysics Data System (ADS)

    Vikas, Hash(0x125f4490)

    2011-02-01

    Evolution of the helium atom in a strong time-dependent (TD) magnetic field ( B) of strength up to 1011 G is investigated through a quantum fluid dynamics (QFD) based current-density functional theory (CDFT). The TD-QFD-CDFT computations are performed through numerical solution of a single generalized nonlinear Schrödinger equation employing vector exchange-correlation potentials and scalar exchange-correlation density functionals that depend both on the electronic charge-density and the current-density. The results are compared with that obtained from a B-TD-QFD-DFT approach (based on conventional TD-DFT) under similar numerical constraints but employing only scalar exchange-correlation potential dependent on electronic charge-density only. The B-TD-QFD-DFT approach, at a particular TD magnetic field-strength, yields electronic charge- and current-densities as well as exchange-correlation potential resembling with that obtained from the time-independent studies involving static (time-independent) magnetic fields. However, TD-QFD-CDFT electronic charge- and current-densities along with the exchange-correlation potential and energy differ significantly from that obtained using B-TD-QFD-DFT approach, particularly at field-strengths >109 G, representing dynamical effects of a TD field. The work concludes that when a helium atom is subjected to a strong TD magnetic field of order >109 G, the conventional TD-DFT based approach differs "dynamically" from the CDFT based approach under similar computational constraints.

  10. Self-consistent Bogoliubov-de Gennes theory of the vortex lattice state in a two-dimensional strongly type-II superconductor at high magnetic fields

    NASA Astrophysics Data System (ADS)

    Zhuravlev, Vladimir; Duan, Wenye; Maniv, Tsofar

    2017-01-01

    A self-consistent Bogoliubov-de Gennes theory of the vortex lattice state in a 2D strong type-II superconductor at high magnetic fields reveals a novel quantum mixed state around the semiclassical Hc 2, characterized by a well-defined Landau-Bloch band structure in the quasiparticle spectrum and suppressed order-parameter amplitude, which sharply crossover into the well-known semiclassical (Helfand-Werthamer) results upon decreasing magnetic field. Application to the 2D superconducting state observed recently on the surface of the topological insulator Sb2Te3 accounts well for the experimental data, revealing a strong type-II superconductor, with unusually low carrier density and very small cyclotron mass, which can be realized only in the strong coupling superconductor limit.

  11. Effect of the Polarization of Photon Splitting on the Cyclotron Lines in Large-Scale Atmospheres with Super-Strong Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Nishimura, Osamu

    2002-04-01

    The cyclotron lines are affected by photon splitting in super-strong magnetized atmospheres (~ 4.4 × 1013 G into which a power-law-type flux is injected. We studied the polarization effect of photon splitting on the cyclotron line formation by treating different modes of splitting. We calculated the emergent spectra for two conditions: only one splitting mode and three splitting modes that could operate in a neutron-star atmosphere with a subcritical magnetic field. Photon splitting can also operate over a larger scale than cyclotron resonant scattering in a neutron-star atmosphere, since photon splitting occurs in a super-strong magnetic field even in the absence of a plasma. We therefore considered atmospheres consisting of lower and higher density regions. Cyclotron resonant scattering is dominant in a higher density region, and photon splitting is dominant in a lower density region. In three splitting modes, we found that the cyclotron absorption l ines are strongly reprocessed by photon splitting, and thus may not be detected even for a magnetic field of about 1.0 × 1013 G in the power-law-type spectra. However, we confirmed that the cyclotron absorption lines are not mostly reprocessed by photon splitting in only one splitting mode.

  12. Strongly magnetized classical plasma models

    NASA Technical Reports Server (NTRS)

    Montgomery, D. C.

    1972-01-01

    The class of plasma processes for which the so-called Vlasov approximation is inadequate is investigated. Results from the equilibrium statistical mechanics of two-dimensional plasmas are derived. These results are independent of the presence of an external dc magnetic field. The nonequilibrium statistical mechanics of the electrostatic guiding-center plasma, a two-dimensional plasma model, is discussed. This model is then generalized to three dimensions. The guiding-center model is relaxed to include finite Larmor radius effects for a two-dimensional plasma.

  13. On the characteristics -extensions, orientation, density, magnetic field- of magnetic clouds/ejecta immediately following its driving part of the -SEP causing- strong-shock surface region

    NASA Astrophysics Data System (ADS)

    Berdichevsky, D. B.

    2012-12-01

    With multi-spacecraft identification of large solar energetic particles (SEP) -events starting 24 September 1977, 1 January and 23 September 1978, 26 March and 24 April, 1979- driven shocks we make a distinction between the shock driving part of the ejecta and its trailing region. We base our study on the analysis of plasma ions -H+, and He++-, and magnetic field observations. Here, we focus on the unique features of the trailing part, i.e., the region of the ejecta immediately behind a leading front moving very close to its driven shock. (I.e., the portion of the shock-surface labeled shock nose.) A shock nose that in an earlier presentation we have shown that generates in the upstream solar wind the unusual disturbance characteristics commonly observed at/near the stagnation point of the so much studied strong Earth's bow-shock, approximately centered in-front of the Earth, along the Sun-Earth line. These events, considered for illustrative purposes here, belong to the era of the HELIO-A, and HELIO-B spacecraft, and the dataset is further complemented with data from the ICE 3, VOYAGER 1, and 2, IMP-8 missions.

  14. Investigations of ultrafast ligand rebinding to heme and heme proteins using temperature and strong magnetic field perturbations

    NASA Astrophysics Data System (ADS)

    Zhang, Zhenyu

    This thesis is written to summarize investigations of the mechanisms that underlie the kinetics of diatomic ligand rebinding to the iron atom of the heme group, which is chelated inside heme proteins. The family of heme proteins is a major object of studies for several branches of scientific research activity. Understanding the ligand binding mechanisms and pathways is one of the major goals for biophysics. My interests mainly focus on the physics of this ligand binding process. Therefore, to investigate the problem, isolated from the influence of the protein matrix, Fe-protophorphyrin IX is chosen as the prototype system in my studies. Myoglobin, the most extensively and intensively studied protein, is another ideal system that allows coupling the protein polypeptide matrix into the investigation. A technique to synchro-lock two laser pulse trains electronically is applied to our pump-probe spectroscopic studies. Based on this technique, a two color, fs/ps pump-probe system is developed which extends the temporal window for our investigation to 13ns and fills a gap existing in previous pump-probe investigations. In order to apply this newly-developed pump-probe laser system to implement systematic studies on the kinetics of diatomic ligand (NO, CO, O2) rebinding to heme and heme proteins, several experimental setups are utilized. In Chapter 1, the essential background knowledge, which helps to understand the iron-ligand interaction, is briefly described. In Chapter 2, in addition to a description of the preparation protocols of protein samples and details of the method for data analysis, three home-made setups are described, which include: a picosecond laser regenerative amplifier, a pump-probe application along the bore (2-inch in diameter) of a superconducting magnet and a temperature-controllable cryostat for spinning sample cell. Chapter 3 presents high magnetic field studies of several heme-ligand or protein-ligand systems. Pump-probe spectroscopy is used to

  15. Dual field theory of strong interactions

    SciTech Connect

    Akers, D.

    1987-07-01

    A dual field theory of strong interactions is derived from a Lagrangian of the Yang-Mills and Higgs fields. The existence of a magnetic monopole of mass 2397 MeV and Dirac charge g = (137/2)e is incorporated into the theory. Unification of the strong, weak, and electromagnetic forces is shown to converge at the mass of the intermediate vector boson W/sup +/-/. The coupling constants of the strong and weak interactions are derived in terms of the fine-structure constant ..cap alpha.. = 1/137.

  16. Alkali metal atoms in strong magnetic fields: "Guiding" atomic transitions foretell the characteristics of all transitions of the D1 line

    NASA Astrophysics Data System (ADS)

    Sargsyan, A.; Hakhumyan, G.; Papoyan, A.; Sarkisyan, D.

    2015-03-01

    It has been shown that the D1 line of atomic vapors of alkali metals excited by π-polarized radiation in a strong transverse magnetic field includes specific "guiding" (indicating) atomic transitions between the magnetic sublevels of the hyperfine structure. The dependence of the frequency shift of the guiding transitions on the magnetic field, as well as on their dipole moments, is asymptotic for all other transitions. An experiment with a nanocell with Rb vapor with a thickness of half the wavelength (λ/2 method) for ensuring a sub-Doppler spectral resolution has completely confirmed the presence of guiding transitions. Two groups of six transitions for 85Rb and two groups of four transitions for 87Rb have been detected in the absorption spectra in magnetic fields above 4 kG. A guiding transition has been identified in each of four groups. Four transitions forbidden at B = 0 have been also detected; with an increase in the magnetic field, their probabilities also approach the probabilities of the guiding transitions.

  17. Strong Magnetic Anomalies on the Lunar Near Side

    NASA Technical Reports Server (NTRS)

    Halekas, J. S.; Mitchell, D. L.; Lin, R. P.; Frey, S.; Acuna, M. H.; Hood, L. L.; Binder, A.

    2000-01-01

    The near side magnetic field is dominated by the demagnetized Imbrium basin and Oceanus Procellarum regions. However, surrounding this area are a number of strong magnetic anomalies, including Rima Sirsalis and Reiner Gamma.

  18. Influence of Landau level mixing on the properties of elementary excitations in graphene in strong magnetic field

    PubMed Central

    2012-01-01

    Massless Dirac electrons in graphene fill Landau levels with energies scaled as square roots of their numbers. Coulomb interaction between electrons leads to mixing of different Landau levels. The relative strength of this interaction depends only on dielectric susceptibility of surrounding medium and can be large in suspended graphene. We consider influence of Landau level mixing on the properties of magnetoexcitons and magnetoplasmons—elementary electron-hole excitations in graphene in quantizing magnetic field. We show that, at small enough background dielectric screening, the mixing leads to very essential change of magnetoexciton and magnetoplasmon dispersion laws in comparison with the lowest Landau level approximation. PACS: 73.22.Pr; 71.35.Ji; 73.43.Mp; 71.70.Gm. PMID:22340359

  19. Influence of the active region design on output characteristics of GaAs/AlGaAs quantum cascade lasers in a strong magnetic field

    NASA Astrophysics Data System (ADS)

    Radovanovic, J.; Mircetic, A.; Milanovic, V.; Ikonic, Z.; Indjin, D.; Harrison, P.; Kelsall, R. W.

    2006-03-01

    We describe the application of our computational model, developed for finding the optical gain in a mid-infrared quantum cascade laser subjected to a strong magnetic field, to two distinct λ ~ 9 µm GaAs-based structures. The additional carrier confinement induced by the field alters the transition rates for the optical- and acoustic-phonon scattering processes from the upper laser level, thus affecting the laser output properties, in particular the optical gain. Within this model, the gain is found by solving the system of rate equations, from which the carrier densities in each level are calculated. Numerical results are presented for magnetic fields between 10 and 60 T, and the band nonparabolicity is taken into account.

  20. Symmetry-breaking magnetic fields create a vortex fluid that exhibits a negative viscosity, active wetting, and strong mixing.

    PubMed

    Martin, James E; Solis, Kyle J

    2014-06-14

    There are many areas of science and technology where being able to generate vigorous, noncontact flow would be desirable. We have discovered that three dimensional, time-dependent electric or magnetic fields having key symmetries can be used to generate controlled fluid motion by the continuous injection of energy. Unlike natural convection, this approach does not require a thermal gradient as an energy source, nor does it require gravity, so space applications are feasible. The result is a highly active material we call a vortex fluid. The homogeneous torque density of this fluid enables it to climb walls, induce ballistic droplet motion, and mix vigorously, even in such complex geometries as porous media. This vortex fluid can also exhibit a negative viscosity, which can immeasurably extend the control range of the "smart fluids" used in electro- and magnetorheological devices and can thus significantly increase their performance. Because the applied fields are uniform and modest in strength, vortex fluids of any scale can be created, making applications of any size, from directing microdroplet motion to controlling damping in magnetorheological dampers that protect bridges and buildings from earthquakes, feasible.

  1. Progress on The GEMS (Gravity Electro-Magnetism-Strong) Theory of Field Unification and Its Application to Space Problems

    SciTech Connect

    Brandenburg, J. E.

    2008-01-21

    Progress on the GEMS (Gravity Electro-Magnetism-Strong), theory is presented as well as its application to space problems. The GEMS theory is now validated through the Standard Model of physics. Derivation of the value of the Gravitation constant based on the observed variation of {alpha} with energy: results in the formula G congruent with ({Dirac_h}/2{pi})c/M{sub {eta}}{sub c}{sup 2} exp(-1/(1.61{alpha})), where {alpha} is the fine structure constant,({Dirac_h}/2{pi}), is Planck's constant, c, is the speed of light, and M{sub {eta}}{sub c} is the mass of the {eta}{sub cc} Charmonium meson that is shown to be identical to that derived from the GEM postulates. Covariant formulation of the GEM theory is now possible through definition of the spacetime metric tensor as a portion of the EM stress tensor normalized by its own trace: g{sub ab} = 4(F{sup c}{sub a}F{sub cb})/(F{sup ab}F{sub ab}), it is found that this results in a massless ground state vacuum and a Newtonian gravitation potential {phi} = 1/2 E{sup 2}/B{sup 2}. It is also found that a Lorentz or flat-space metric is recovered in the limit of a full spectrum ZPF.

  2. Jet quenching parameter of the quark-gluon plasma in a strong magnetic field: Perturbative QCD and AdS /CFT correspondence

    NASA Astrophysics Data System (ADS)

    Li, Shiyong; Mamo, Kiminad A.; Yee, Ho-Ung

    2016-10-01

    We compute the jet quenching parameter q ^ of a quark-gluon plasma in the presence of a strong magnetic field using perturbative QCD (pQCD) in the weakly coupled regime, and AdS /CFT correspondence in the strongly coupled regime of N =4 super Yang-Mills. In the weakly coupled regime, we compute q ^ in pQCD at complete leading order (that is, leading log as well as the constant under the log) in the QCD coupling constant αs, assuming the hierarchy of scales αse B ≪T2≪e B . We consider two cases of jet orientations with respect to the magnetic field: 1) the case of a jet moving parallel to the magnetic field; 2) the case of a jet moving perpendicular to the magnetic field. In the former case, we find q ^ ˜αs2(e B )T log (1 /αs) , while in the latter we have q ^ ˜αs2(e B )T log (T2/αse B ) . In both cases, this leading-order result arises from the scatterings with thermally populated lowest-Landau-level quarks. In the strongly coupled regime described by the AdS /CFT correspondence, we find q ^ ˜√{λ }(e B )T or q ^ ˜√{λ }√{e B }T2 in the same hierarchy of T2≪e B depending on whether the jet is moving parallel or perpendicular to the magnetic field, respectively, which indicates a universal dependence of q ^ on (e B )T in both regimes for the parallel case, the origin of which should be the transverse density of lowest-Landau-level states proportional to e B . Finally, the asymmetric transverse momentum diffusion in the case of a jet moving perpendicular to the magnetic field may give an interesting azimuthal asymmetry of the gluon bremsstrahlung spectrum in the Baier-Dokshitzer-Mueller-Peigne-Schiff and Zakharov (BDMPS-Z) formalism.

  3. The effects of ultra-strong magnetic fields on electron capture rates for iron group nuclei in the outer crust of magnetars

    NASA Astrophysics Data System (ADS)

    Du, Jun; Luo, Zhi-Quan; Zhang, Jie

    2014-06-01

    Based on the work of Wang et al. (Chin. Phys. Lett. 29:049701, 2012), we re-investigated electron capture on iron group nuclei in the outer crust of magnetars and studied magnetar evolution. Effects of ultra-strong magnetic field on electron capture rates for 57Co have been analyzed in the nuclear shell model and under the Landau-level-quantization approximation, and the electron capture rates and the neutrino energy loss rates on iron group nuclei in the outer crust of magnetar have been calculated. The results show that electron capture rates on 57Co are increase greatly in the ultra-strong magnetic field, and above 3 orders of magnitude generally; and the neutrino energy loss rates by electron capture on iron group nuclei increase above 3 orders of magnitude in the range from B=4.414×1013 G to B=4.414×1015 G. These conclusions play an important role in future studying the evolution of magnetar. Furthermore, we modify the expressions of the electron chemical potential (Fermi energy) and phase space factor by introducing Dirac δ-function, and select appropriate parameters of temperature T, magnetic field B and matter density ρ in the our crust, thus our results will be reliable than those of Wang et al.

  4. Estimation of changes in fitness components and antioxidant defense of Drosophila subobscura (Insecta, Diptera) after exposure to 2.4 T strong static magnetic field.

    PubMed

    Todorović, Dajana; Perić-Mataruga, Vesna; Mirčić, Dejan; Ristić-Djurović, Jasna; Prolić, Zlatko; Petković, Branka; Savić, Tatjana

    2015-04-01

    As an ecological factor, a magnetic field can affect insects causing a wide range of responses. The main purpose of this study was to analyze the fitness components (postembryonic development and viability of individuals) and the antioxidant defense (superoxide dismutase, catalase, and total glutathione) in laboratory strains of Drosophila subobscura, originating from oak and beech forests after exposure to the strong static magnet (2.4 T, VINCY Cyclotron magnet). The first instar larvae were placed near the north pole (N group) or the south pole (S group) of the magnet for 2 h. Oak and beech populations of D. subobscura had longer development time and lower viability in N and S groups compared to controls. These differences were significant only in S group of oak population and in N group of beech population. Total glutathione content was significantly decreased in both exposed groups of oak population, while catalase activity was significantly increased in both exposed groups of beech population. Being significantly decreased in both exposed groups of oak population and significantly increased in S group of beech population in comparison to controls, superoxide dismutase activity was observed in different values. According to the results, it can be stated that applied static magnetic field could be considered a potential stressor influencing the fitness components and antioxidant defense in Drosophila flies.

  5. Magnetic field tuning of an excitonic insulator between the weak and strong coupling regimes in quantum limit graphite [Tunable excitonic insulator in quantum limit graphite

    DOE PAGES

    Zhu, Zengwei; McDonald, R. D.; Shekhter, A.; ...

    2017-05-04

    Here, the excitonic insulator phase has long been predicted to form in proximity to a band gap opening in the underlying band structure. The character of the pairing is conjectured to crossover from weak (BCS-like) to strong coupling (BEC-like) as the underlying band structure is tuned from the metallic to the insulating side of the gap opening. Here we report the high-magnetic field phase diagram of graphite to exhibit just such a crossover. By way of comprehensive angle-resolved magnetoresistance measurements, we demonstrate that the underlying band gap opening occurs inside the magnetic field-induced phase, paving the way for a systematicmore » study of the BCS-BEC-like crossover by means of conventional condensed matter probes.« less

  6. Electrophoresis in strong electric fields.

    PubMed

    Barany, Sandor

    2009-01-01

    Two kinds of non-linear electrophoresis (ef) that can be detected in strong electric fields (several hundred V/cm) are considered. The first ("classical" non-linear ef) is due to the interaction of the outer field with field-induced ionic charges in the electric double layer (EDL) under conditions, when field-induced variations of electrolyte concentration remain to be small comparatively to its equilibrium value. According to the Shilov theory, the non-linear component of the electrophoretic velocity for dielectric particles is proportional to the cubic power of the applied field strength (cubic electrophoresis) and to the second power of the particles radius; it is independent of the zeta-potential but is determined by the surface conductivity of particles. The second one, the so-called "superfast electrophoresis" is connected with the interaction of a strong outer field with a secondary diffuse layer of counterions (space charge) that is induced outside the primary (classical) diffuse EDL by the external field itself because of concentration polarization. The Dukhin-Mishchuk theory of "superfast electrophoresis" predicts quadratic dependence of the electrophoretic velocity of unipolar (ionically or electronically) conducting particles on the external field gradient and linear dependence on the particle's size in strong electric fields. These are in sharp contrast to the laws of classical electrophoresis (no dependence of V(ef) on the particle's size and linear dependence on the electric field gradient). A new method to measure the ef velocity of particles in strong electric fields is developed that is based on separation of the effects of sedimentation and electrophoresis using videoimaging and a new flowcell and use of short electric pulses. To test the "classical" non-linear electrophoresis, we have measured the ef velocity of non-conducting polystyrene, aluminium-oxide and (semiconductor) graphite particles as well as Saccharomice cerevisiae yeast cells as a

  7. Directed flow of charm quarks as a witness of the initial strong magnetic field in ultra-relativistic heavy ion collisions

    NASA Astrophysics Data System (ADS)

    Das, Santosh K.; Plumari, S.; Chatterjee, S.; Alam, J.; Scardina, F.; Greco, V.

    2017-05-01

    Ultra-relativistic Heavy-Ion Collision (HIC) generates very strong initial magnetic field (B →) inducing a vorticity in the reaction plane. The high B → influences the evolution dynamics that is opposed by the large Faraday current due to electric field generated by the time varying B → . We show that the resultant effects entail a significantly large directed flow (v1) of charm quarks (CQs) compared to light quarks due to a combination of several favorable conditions for CQs, mainly: (i) unlike light quarks formation time scale of CQs, τf ≃ 0.1 fm /c is comparable to the time scale when B → attains its maximum value and (ii) the kinetic relaxation time of CQs is similar to the QGP lifetime, this helps the CQ to retain the initial kick picked up from the electromagnetic field in the transverse direction. The effect is also odd under charge exchange allowing to distinguish it from the vorticity of the bulk matter due to the initial angular momentum conservation; conjointly thanks to its mass, Mc > >ΛQCD, there should be no mixing with the chiral magnetic dynamics. Hence CQs provide very crucial and independent information on the strength of the magnetic field produced in HIC.

  8. Vestibular stimulation by magnetic fields

    PubMed Central

    Ward, Bryan K.; Roberts, Dale C.; Della Santina, Charles C.; Carey, John P.; Zee, David S.

    2015-01-01

    Individuals working next to strong static magnetic fields occasionally report disorientation and vertigo. With the increasing strength of magnetic fields used for magnetic resonance imaging (MRI) studies, these reports have become more common. It was recently learned that humans, mice and zebrafish all demonstrate behaviors consistent with constant peripheral vestibular stimulation while inside a strong, static magnetic field. The proposed mechanism for this effect involves a Lorentz force resulting from the interaction of a strong static magnetic field with naturally occurring ionic currents flowing through the inner ear endolymph into vestibular hair cells. The resulting force within the endolymph is strong enough to displace the lateral semicircular canal cupula, inducing vertigo and the horizontal nystagmus seen in normal mice and in humans. This review explores the evidence for interactions of magnetic fields with the vestibular system. PMID:25735662

  9. A metafluid exhibiting strong optical magnetism.

    PubMed

    Sheikholeslami, Sassan N; Alaeian, Hadiseh; Koh, Ai Leen; Dionne, Jennifer A

    2013-09-11

    Advances in the field of metamaterials have enabled unprecedented control of light-matter interactions. Metamaterial constituents support high-frequency electric and magnetic dipoles, which can be used as building blocks for new materials capable of negative refraction, electromagnetic cloaking, strong visible-frequency circular dichroism, and enhancing magnetic or chiral transitions in ions and molecules. While all metamaterials to date have existed in the solid-state, considerable interest has emerged in designing a colloidal metamaterial or "metafluid". Such metafluids would combine the advantages of solution-based processing with facile integration into conventional optical components. Here we demonstrate the colloidal synthesis of an isotropic metafluid that exhibits a strong magnetic response at visible frequencies. Protein-antibody interactions are used to direct the solution-phase self-assembly of discrete metamolecules comprised of silver nanoparticles tightly packed around a single dielectric core. The electric and magnetic response of individual metamolecules and the bulk metamaterial solution are directly probed with optical scattering and spectroscopy. Effective medium calculations indicate that the bulk metamaterial exhibits a negative effective permeability and a negative refractive index at modest fill factors. This metafluid can be synthesized in large-quantity and high-quality and may accelerate development of advanced nanophotonic and metamaterial devices.

  10. Uniformly accurate Particle-in-Cell method for the long time solution of the two-dimensional Vlasov-Poisson equation with uniform strong magnetic field

    NASA Astrophysics Data System (ADS)

    Crouseilles, Nicolas; Lemou, Mohammed; Méhats, Florian; Zhao, Xiaofei

    2017-10-01

    In this work, we focus on the numerical resolution of the four dimensional phase space Vlasov-Poisson system subject to a uniform strong external magnetic field. To do so, we consider a Particle-in-Cell based method, for which the characteristics are reformulated by means of the two-scale formalism, which is well-adapted to handle highly-oscillatory equations. Then, a numerical scheme is derived for the two-scale equations. The so-obtained scheme enjoys a uniform accuracy property, meaning that its accuracy does not depend on the small parameter. Several numerical results illustrate the capabilities of the method.

  11. Variational calculation of ground-state energy of iron atoms and condensed matter in strong magnetic fields. [at neutron star surfaces

    NASA Technical Reports Server (NTRS)

    Flowers, E. G.; Ruderman, M. A.; Lee, J.-F.; Sutherland, P. G.; Hillebrandt, W.; Mueller, E.

    1977-01-01

    Variational calculations of the binding energies of iron atoms and condensed matter in strong magnetic fields (greater than 10 to the 12th gauss). These calculations include the electron exchange energy. The cohesive energy of the condensed matter, which is the difference between these two binding energies, is of interest in pulsar theories and in the description of the surfaces of neutron stars. It is found that the cohesive energy ranges from 2.6 keV to 8.0 keV.

  12. Variational calculation of ground-state energy of iron atoms and condensed matter in strong magnetic fields. [at neutron star surfaces

    NASA Technical Reports Server (NTRS)

    Flowers, E. G.; Ruderman, M. A.; Lee, J.-F.; Sutherland, P. G.; Hillebrandt, W.; Mueller, E.

    1977-01-01

    Variational calculations of the binding energies of iron atoms and condensed matter in strong magnetic fields (greater than 10 to the 12th gauss). These calculations include the electron exchange energy. The cohesive energy of the condensed matter, which is the difference between these two binding energies, is of interest in pulsar theories and in the description of the surfaces of neutron stars. It is found that the cohesive energy ranges from 2.6 keV to 8.0 keV.

  13. Strong hydromagnetic fluctuations in the Comet P/Halley magnetosphere observed by the Giotto magnetic field experiment

    NASA Technical Reports Server (NTRS)

    Glassmeier, K. H.; Neubauer, F. M.; Acuna, M. H.; Marian, F.

    1986-01-01

    Strong hydromagnetic fluctuations were observed in the induced magnetosphere of comet Halley. Several regions were identified showing either strong turbulence, characterized by the absence of strong fluctuations, or showing isolated, quasi-coherent wave trains above a turbulent background. Visual inspection of the wave trains shows no preferred sense of polarization, i.e., they may be of transverse, compressional, or mixed polarization. Spectral analysis shows peak power at various frequencies, corresponding, for example, to water group or hydrogen ion cyclotron resonances. Analysis of a peculiar type of oscillation with 25 sec period suggests strong contributions from off-angle propagating waves.

  14. MAVEN Observations of Magnetic Flux Ropes with a Strong Field Amplitude in the Martian Magnetosheath During the ICME Passage on 8 March 2015

    NASA Technical Reports Server (NTRS)

    Hara, Takuya; Luhmann, Janet G.; Halekas, Jasper S.; Espley, Jared R.; Seki, Kanako; Brain, David A.; Hasegawa, Hiroshi; McFadden, James P.; Mitchell, David L.; Mazelle, Christian; Harada, Yuki; Livi, Roberto; DiBraccio, Gina A.; Connerney, John E. P.; Andersson, Lailla; Jakosky, Bruce M.

    2016-01-01

    We present initial results of strong field amplitude flux ropes observed by Mars Atmosphere and Volatile EvolutioN (MAVEN) mission around Mars during the interplanetary coronal mass ejection (ICME) passage on 8 March 2015. The observed durations were shorter than 5 s and the magnetic field magnitudes peaked above 80 nT, which is a few times stronger than those usually seen in the magnetosheath barrier. These are the first unique observations that MAVEN detected such flux ropes with a strong field at high altitudes (greater than 5000 km). Across these structures, MAVEN coincidentally measured planetary heavy ions with energies higher than a few keV. The spatial properties inferred from the Grad-Shafranov equation suggest that the speed of the structure can be estimated at least an order of magnitude faster than those previously reported quiet-time counterparts. Hence, the space weather event like the ICME passage can be responsible for generating the observed strong field, fast-traveling flux ropes.

  15. MAVEN observations of magnetic flux ropes with a strong field amplitude in the Martian magnetosheath during the ICME passage on 8 March 2015

    NASA Astrophysics Data System (ADS)

    Hara, Takuya; Luhmann, Janet G.; Halekas, Jasper S.; Espley, Jared R.; Seki, Kanako; Brain, David A.; Hasegawa, Hiroshi; McFadden, James P.; Mitchell, David L.; Mazelle, Christian; Harada, Yuki; Livi, Roberto; DiBraccio, Gina A.; Connerney, John E. P.; Andersson, Lailla; Jakosky, Bruce M.

    2016-05-01

    We present initial results of strong field amplitude flux ropes observed by Mars Atmosphere and Volatile EvolutioN (MAVEN) mission around Mars during the interplanetary coronal mass ejection (ICME) passage on 8 March 2015. The observed durations were shorter than 5 s and the magnetic field magnitudes peaked above 80 nT, which is a few times stronger than those usually seen in the magnetosheath barrier. These are the first unique observations that MAVEN detected such flux ropes with a strong field at high altitudes (>5000 km). Across these structures, MAVEN coincidentally measured planetary heavy ions with energies higher than a few keV. The spatial properties inferred from the Grad-Shafranov equation suggest that the speed of the structure can be estimated at least an order of magnitude faster than those previously reported quiet-time counterparts. Hence, the space weather event like the ICME passage can be responsible for generating the observed strong field, fast-traveling flux ropes.

  16. MAVEN Observations of Magnetic Flux Ropes with a Strong Field Amplitude in the Martian Magnetosheath During the ICME Passage on 8 March 2015

    NASA Technical Reports Server (NTRS)

    Hara, Takuya; Luhmann, Janet G.; Halekas, Jasper S.; Espley, Jared R.; Seki, Kanako; Brain, David A.; Hasegawa, Hiroshi; McFadden, James P.; Mitchell, David L.; Mazelle, Christian; hide

    2016-01-01

    We present initial results of strong field amplitude flux ropes observed by Mars Atmosphere and Volatile EvolutioN (MAVEN) mission around Mars during the interplanetary coronal mass ejection (ICME) passage on 8 March 2015. The observed durations were shorter than 5 s and the magnetic field magnitudes peaked above 80 nT, which is a few times stronger than those usually seen in the magnetosheath barrier. These are the first unique observations that MAVEN detected such flux ropes with a strong field at high altitudes (greater than 5000 km). Across these structures, MAVEN coincidentally measured planetary heavy ions with energies higher than a few keV. The spatial properties inferred from the Grad-Shafranov equation suggest that the speed of the structure can be estimated at least an order of magnitude faster than those previously reported quiet-time counterparts. Hence, the space weather event like the ICME passage can be responsible for generating the observed strong field, fast-traveling flux ropes.

  17. Magnetic Field Arches

    NASA Image and Video Library

    2016-09-28

    When an active region rotated into a profile view, SDO was able to capture the magnificent loops arching above an active region (Sept. 28-29, 2016). Active region are areas of strong magnetic fields. The magnetic field lines above these regions are illuminated by charged particles spiraling along them. The images were taken in a wavelength of extreme ultraviolet light. The video covers 12 hours of activity. The Earth was inset to give a sense of the scale of these towering arches. Movies are available at http://photojournal.jpl.nasa.gov/catalog/PIA21101

  18. Magnetic fields from inflation?

    SciTech Connect

    Demozzi, Vittoria; Mukhanov, Viatcheslav; Rubinstein, Hector E-mail: viatcheslav.mukhanov@physik.uni-muenchen.de

    2009-08-01

    We consider the possibility of generation of the primordial magnetic field on inflation and show that the effect of the back reaction of this field can be very important. Assuming that the back reaction does not spoil inflation we find a rather strong restriction on the amplitude of the primordial field which could be generated on inflation. Namely, this amplitude recalculated to the present epoch cannot exceed 10{sup −32}G in Mpc scales. This field seems to be too small to be amplified to the observable values by a possible dynamo mechanism.

  19. Influence of Strongly Magnetized Plasma on Photon Splitting

    SciTech Connect

    Rumyantsev, D.A.; Chistyakov, M.V.

    2005-10-01

    The photon splitting {gamma} {yields} {gamma}{gamma} in a strongly magnetized medium of arbitrary temperature and chemical potential is considered. In comparison with the case of a pure magnetic field, a new photon splitting channel is shown to be possible below the electron-positron pair production threshold. The partial splitting amplitudes and probabilities are calculated by taking into account the photon dispersion in a strong magnetic field and a charge-symmetric plasma. An enhancement of the photon splitting probability compared to the case of a magnetic field without plasma has been found to be possible under certain conditions.

  20. Magnetic field sensor

    NASA Astrophysics Data System (ADS)

    Silva, Nicolas

    2012-09-01

    Earlier papers1-3 in this journal have described experiments on measuring the magnetic fields of current-carrying wires and permanent magnets using magnetic field probes of various kinds. This paper explains how to use an iPad and the free app MagnetMeter-3D Vector Magnetometer and Accelerometer4 (compass HD) to measure the magnetic fields.

  1. The First in situ Observation of Kelvin-Helmholtz Waves at High-Latitude Magnetopause during Strongly Dawnward Interplanetary Magnetic Field Conditions

    NASA Technical Reports Server (NTRS)

    Hwang, K.-J.; Goldstein, M. L.; Kuznetsova, M. M.; Wang, Y.; Vinas, A. F.; Sibeck, D. G.

    2012-01-01

    We report the first in situ observation of high-latitude magnetopause (near the northern duskward cusp) Kelvin-Helmholtz waves (KHW) by Cluster on January 12, 2003, under strongly dawnward interplanetary magnetic field (IMF) conditions. The fluctuations unstable to Kelvin-Helmholtz instability (KHI) are found to propagate mostly tailward, i.e., along the direction almost 90 deg. to both the magnetosheath and geomagnetic fields, which lowers the threshold of the KHI. The magnetic configuration across the boundary layer near the northern duskward cusp region during dawnward IMF is similar to that in the low-latitude boundary layer under northward IMF, in that (1) both magnetosheath and magnetospheric fields across the local boundary layer constitute the lowest magnetic shear and (2) the tailward propagation of the KHW is perpendicular to both fields. Approximately 3-hour-long periods of the KHW during dawnward IMF are followed by the rapid expansion of the dayside magnetosphere associated with the passage of an IMF discontinuity that characterizes an abrupt change in IMF cone angle, Phi = acos (B(sub x) / absolute value of Beta), from approx. 90 to approx. 10. Cluster, which was on its outbound trajectory, continued observing the boundary waves at the northern evening-side magnetopause during sunward IMF conditions following the passage of the IMF discontinuity. By comparing the signatures of boundary fluctuations before and after the IMF discontinuity, we report that the frequencies of the most unstable KH modes increased after the discontinuity passed. This result demonstrates that differences in IMF orientations (especially in f) are associated with the properties of KHW at the high-latitude magnetopause due to variations in thickness of the boundary layer, and/or width of the KH-unstable band on the surface of the dayside magnetopause.

  2. Magnetic fields at uranus.

    PubMed

    Ness, N F; Acuña, M H; Behannon, K W; Burlaga, L F; Connerney, J E; Lepping, R P; Neubauer, F M

    1986-07-04

    The magnetic field experiment on the Voyager 2 spacecraft revealed a strong planetary magnetic field of Uranus and an associated magnetosphere and fully developed bipolar masnetic tail. The detached bow shock wave in the solar wind supersonic flow was observed upstream at 23.7 Uranus radii (1 R(U) = 25,600 km) and the magnetopause boundary at 18.0 R(U), near the planet-sun line. A miaximum magnetic field of 413 nanotesla was observed at 4.19 R(U ), just before closest approach. Initial analyses reveal that the planetary magnetic field is well represented by that of a dipole offset from the center of the planet by 0.3 R(U). The angle between Uranus' angular momentum vector and the dipole moment vector has the surprisingly large value of 60 degrees. Thus, in an astrophysical context, the field of Uranus may be described as that of an oblique rotator. The dipole moment of 0.23 gauss R(3)(U), combined with the large spatial offset, leads to minimum and maximum magnetic fields on the surface of the planet of approximately 0.1 and 1.1 gauss, respectively. The rotation period of the magnetic field and hence that of the interior of the planet is estimated to be 17.29+/- 0.10 hours; the magnetotail rotates about the planet-sun line with the same period. Thelarge offset and tilt lead to auroral zones far from the planetary rotation axis poles. The rings and the moons are embedded deep within the magnetosphere, and, because of the large dipole tilt, they will have a profound and diurnally varying influence as absorbers of the trapped radiation belt particles.

  3. Dynamical chiral symmetry breaking in NJL Model with a strong background magnetic field and Lorentz-violating extension of the Standard Model

    NASA Astrophysics Data System (ADS)

    Luo, Cui-Bai; Shi, Song; Xia, Yong-Hui; Zong, Hong-Shi

    2017-06-01

    The Eigenstate Method has been developed to deduce the fermion propagator with a constant external magnetic field. In general, we find its result is equivalent to other methods and this new method is more convenient, especially when one evaluates the contribution from the infinitesimal imaginary term of the fermion propagator. Using the Eigenstate Method we try to discuss whether the infinitesimal imaginary frequency of the fermion propagator in a strong magnetic field and Lorentz-violating extension of the minimal SU(3)×SU(2)×SU(1) Standard Model could have a significant influence on the dynamical mass. When the imaginary term of the fermion propagator in this model is not trivial , this model gives a correction to the dynamical mass. When one does not consider the influence from the imaginary term , there is another correction from the conventional term. Under both circumstances, chiral symmetry is broken. Supported in part by National Natural Science Foundation of China (11275097, 11475085, 11535005, 11690030), China Postdoctoral Science Foundation (2014M561621), and Jiangsu Planned Projects for Postdoctoral Research Funds (1401116C)

  4. Strongly magnetized rotating dipole in general relativity

    NASA Astrophysics Data System (ADS)

    Pétri, J.

    2016-10-01

    Context. Electromagnetic waves arise in many areas of physics. Solutions are difficult to find in the general case. Aims: We numerically integrate Maxwell equations in a 3D spherical polar coordinate system. Methods: Straightforward finite difference methods would lead to a coordinate singularity along the polar axis. Spectral methods are better suited for such artificial singularities that are related to the choice of a coordinate system. When the radiating object rotates like a star, for example, special classes of solutions to Maxwell equations are worthwhile to study, such as quasi-stationary regimes. Moreover, in high-energy astrophysics, strong gravitational and magnetic fields are present especially around rotating neutron stars. Results: To study such systems, we designed an algorithm to solve the time-dependent Maxwell equations in spherical polar coordinates including general relativity and quantum electrodynamical corrections to leading order. As a diagnostic, we computed the spin-down luminosity expected for these stars and compared it to the classical or non-relativistic and non-quantum mechanical results. Conclusions: Quantum electrodynamics leads to an irrelevant change in the spin-down luminosity even for a magnetic field of about the critical value of 4.4 × 109 T. Therefore the braking index remains close to its value for a point dipole in vacuum, namely n = 3. The same conclusion holds for a general-relativistic quantum electrodynamically corrected force-free magnetosphere.

  5. Two strongly contrasting Λ-systems in the D{sub 1} line of {sup 87}Rb in a transverse magnetic field

    SciTech Connect

    Sargsyan, A.; Sarkisyan, D.; Margalit, L.; Wilson-Gordon, A. D.

    2016-06-15

    Four different types of spectroscopic cells that cover all possible existing versions of sealed-off cells (containing alkali atomic vapor) characterized by drastically different relaxation rates γ{sub rel} are used to study the electromagnetically induced transparency spectra of two Λ-systems in the D{sub 1} line of {sup 87}Rb in the presence of transverse magnetic field. Two cw narrowband diode-lasers are used to form the coupling laser radiation (with a fixed frequency) and the probe radiation with a tunable frequency. Two strongly contrasting Λ-systems are found: the first shows resonances that are transformed from dark resonances to bright resonances in all cases apart from nanocells, whereas the second shows four dark resonances in all four different types of cell. The theoretical simulations are in good agreement with the experimental results.

  6. Cosmological magnetic fields

    NASA Astrophysics Data System (ADS)

    Kunze, Kerstin E.

    2013-12-01

    Magnetic fields are observed on nearly all scales in the Universe, from stars and galaxies up to galaxy clusters and even beyond. The origin of cosmic magnetic fields is still an open question, however a large class of models puts its origin in the very early Universe. A magnetic dynamo amplifying an initial seed magnetic field could explain the present day strength of the galactic magnetic field. However, it is still an open problem how and when this initial magnetic field was created. Observations of the cosmic microwave background (CMB) provide a window to the early Universe and might therefore be able to tell us whether cosmic magnetic fields are of a primordial cosmological origin and at the same time constrain its parameters. We will give an overview of the observational evidence of large-scale magnetic fields, describe generation mechanisms of primordial magnetic fields and possible imprints in the CMB.

  7. Facility Measures Magnetic Fields

    NASA Technical Reports Server (NTRS)

    Honess, Shawn B.; Narvaez, Pablo; Mcauley, James M.

    1991-01-01

    Partly automated facility measures and computes steady near magnetic field produced by object. Designed to determine magnetic fields of equipment to be installed on spacecraft including sensitive magnetometers, with view toward application of compensating fields to reduce interfernece with spacecraft-magnetometer readings. Because of its convenient operating features and sensitivity of its measurements, facility serves as prototype for similar facilities devoted to magnetic characterization of medical equipment, magnets for high-energy particle accelerators, and magnetic materials.

  8. Martian external magnetic field proxies

    NASA Astrophysics Data System (ADS)

    Langlais, Benoit; Civet, Francois

    2015-04-01

    Mars possesses no dynamic magnetic field of internal origin as it is the case for the Earth or for Mercury. Instead Mars is characterized by an intense and localized magnetic field of crustal origin. This field is the result of past magnetization and demagnetization processes, and reflects its evolution. The Interplanetary Magnetic Field (IMF) interacts with Mars' ionized environment to create an external magnetic field. This external field is weak compared to lithospheric one but very dynamic, and may hamper the detailed analysis of the internal magnetic field at some places or times. Because there are currently no magnetic field measurements made at Mars' surface, it is not possible to directly monitor the external field temporal variability as it is done in Earth's ground magnetic observatories. In this study we examine to indirect ways of quantifying this external field. First we use the Advanced Composition Explorer (ACE) mission which measures the solar wind about one hour upstream of the bow-shock resulting from the interaction between the solar wind and the Earth's internal magnetic field. These measurements are extrapolated to Mars' position taking into account the orbital configurations of the Mars-Earth system and the velocity of particles carrying the IMF. Second we directly use Mars Global Surveyor magnetic field measurements to quantify the level of variability of the external field. We subtract from the measurements the internal field which is otherwise modeled, and bin the residuals first on a spatial and then on a temporal mesh. This allows to compute daily or semi daily index. We present a comparison of these two proxies and demonstrate their complementarity. We also illustrate our analysis by comparing our Martian external field proxies to terrestrial index at epochs of known strong activity. These proxies will especially be useful for upcoming magnetic field measurements made around or at the surface of Mars.

  9. Caution: Strong Gravitational Field Present

    ERIC Educational Resources Information Center

    Reif, Marc

    2014-01-01

    I came up with a new way to introduce the concept of a constant gravitational field near the surface of the Earth. I made "g-field detectors" (see Fig. 1 ) and suspended them by strings from the ceiling in a regular spacing. The detectors are cardstock arrows with a hole punched out of them and the letter "g" in the center.

  10. Caution: Strong Gravitational Field Present

    ERIC Educational Resources Information Center

    Reif, Marc

    2014-01-01

    I came up with a new way to introduce the concept of a constant gravitational field near the surface of the Earth. I made "g-field detectors" (see Fig. 1 ) and suspended them by strings from the ceiling in a regular spacing. The detectors are cardstock arrows with a hole punched out of them and the letter "g" in the center.

  11. Quantum Interference in the Spin-Polarized Heavy Fermion Compound CeB{sub 6} : Evidence for Topological Deformation of the Fermi Surface in Strong Magnetic Fields

    SciTech Connect

    Harrison, N.; Hall, D.W.; Goodrich, R.G.; Hall, D.W.; Fisk, Z.; Vuillemin, J.J.

    1998-07-01

    We report susceptibility experiments in magnetic fields up to 60thinspthinspT and show conclusively that the de Haas{endash}van Alphen oscillations originate from a single spin Fermi surface. New observed frequencies present in magnetic breakdown and quantum interference oscillations indicate that the Fermi-surface topology changes as a function of the applied field while maintaining a constant volume. These results are not expected from the Anderson lattice model. {copyright} {ital 1998} {ital The American Physical Society}

  12. Minireview: Biological effects of magnetic fields

    SciTech Connect

    Villa, M.; Mustarelli, P. ); Caprotti, M. )

    1991-01-01

    The literature about the biological effects of magnetic fields is reviewed. The authors begin by discussing the weak and/or time variable fields, responsible for subtle changes in the circadian rhythms of superior animals, which are believed to be induced by same sort of resonant mechanism. The safety issues related with the strong magnetic fields and gradients generated by clinical NMR magnets are then considered. The last portion summarizes the debate about the biological effects of strong and uniform magnetic fields.

  13. Experimental exploration of novel semimetal state in strong anisotropic Pyrochlore iridate Nd2lr2O7 under high magnetic field

    NASA Astrophysics Data System (ADS)

    Tian, Z. M.; Kohama, Y.; Tomita, T.; Ishikawa, J.; Mairo, H.; Kindo, K.; Nakatsuji, S.

    2016-02-01

    We report the anisotropic magnetotransport of Nd2Ir2O7 single crystal under high magnetic field (B) up to 50 T with B along various directions. Only for B // [001] direction, a novel semimetal state is realized under high magnetic field evidenced by a field-induced insulating-semimetalic phase transition with critical field BMI∼12 T related to the destruction of all-in-all-out (AIAO) state. In contrast, abnormal magnetotransport hysteresis behavior is observed for B // [111] direction below the metal-insulator transition temperature (TMI), and magnetotransport reveals the Ir spin structure keep in the AIAO state under high magnetic field with temperature just below TMI, in prospect to realize Weyl semimetal state.

  14. Magnetic fields around evolved stars

    NASA Astrophysics Data System (ADS)

    Leal-Ferreira, M.; Vlemmings, W.; Kemball, A.; Amiri, N.; Maercker, M.; Ramstedt, S.; Olofsson, G.

    2014-04-01

    A number of mechanisms, such as magnetic fields, (binary) companions and circumstellar disks have been suggested to be the cause of non-spherical PNe and in particular collimated outflows. This work investigates one of these mechanisms: the magnetic fields. While MHD simulations show that the fields can indeed be important, few observations of magnetic fields have been done so far. We used the VLBA to observe five evolved stars, with the goal of detecting the magnetic field by means of water maser polarization. The sample consists in four AGB stars (IK Tau, RT Vir, IRC+60370 and AP Lyn) and one pPN (OH231.8+4.2). In four of the five sources, several strong maser features were detected allowing us to measure the linear and/or circular polarization. Based on the circular polarization detections, we infer the strength of the component of the field along the line of sight to be between ~30 mG and ~330 mG in the water maser regions of these four sources. When extrapolated to the surface of the stars, the magnetic field strength would be between a few hundred mG and a few Gauss when assuming a toroidal field geometry and higher when assuming more complex magnetic fields. We conclude that the magnetic energy we derived in the water maser regions is higher than the thermal and kinetic energy, leading to the conclusion that, indeed, magnetic fields probably play an important role in shaping Planetary Nebulae.

  15. Transport Theory for Plasmas that are Strongly Magnetized and Strongly Coupled

    NASA Astrophysics Data System (ADS)

    Baalrud, Scott; Daligault, Jerome

    2016-10-01

    Plasmas with components that are magnetized, strongly coupled, or both arise in a variety of frontier plasma physics experiments including magnetized dusty plasmas, nonneutral plasmas, magnetized ICF concepts, as well as from self-generated fields in ICF. Here, a species is considered strongly magnetized if the gyroradius is smaller than the spatial scale over which Coulomb interactions occur. A theory for transport properties is described that treats a wide range of both coupling and magnetization strengths. The approach is based on an extension of the recent effective potential transport theory to include a strong magnetic field. The underlying kinetic theory is based on an extension of the Boltzmann equation to include a strong magnetic field in the dynamics of binary scattering events. Corresponding magnetohydrodynamic equations are derived by solving the kinetic equation using a Chapman-Enskog like spectral method. Results are compared with classical molecular dynamics simulations of self-diffusion of the one component plasmas, and with simulations of parallel to perpendicular temperature equilibration of an initially anisotropic distribution. This material is based upon work supported by AFOSR Award FA9550-16-1-0221 and DOE OFES Award DE-SC0016159.

  16. Fast ignition realization experiment with high-contrast kilo-joule peta-watt LFEX laser and strong external magnetic field

    NASA Astrophysics Data System (ADS)

    Fujioka, Shinsuke; Arikawa, Yasunobu; Kojima, Sadaoki; Johzaki, Tomoyuki; Nagatomo, Hideo; Sawada, Hiroshi; Lee, Seung Ho; Shiroto, Takashi; Ohnishi, Naofumi; Morace, Alessio; Vaisseau, Xavier; Sakata, Shohei; Abe, Yuki; Matsuo, Kazuki; Farley Law, King Fai; Tosaki, Shota; Yogo, Akifumi; Shigemori, Keisuke; Hironaka, Yoichiro; Zhang, Zhe; Sunahara, Atsushi; Ozaki, Tetsuo; Sakagami, Hitoshi; Mima, Kunioki; Fujimoto, Yasushi; Yamanoi, Kohei; Norimatsu, Takayoshi; Tokita, Shigeki; Nakata, Yoshiki; Kawanaka, Junji; Jitsuno, Takahisa; Miyanaga, Noriaki; Nakai, Mitsuo; Nishimura, Hiroaki; Shiraga, Hiroyuki; Kondo, Kotaro; Bailly-Grandvaux, Mathieu; Bellei, Claudio; Santos, João Jorge; Azechi, Hiroshi

    2016-05-01

    plasma. Following the above improvements, conversion of 13% of the LFEX laser energy to a low energy portion of the REB, whose slope temperature is 0.7 MeV, which is close to the ponderomotive scaling value, was achieved. To meet the second requirement, the compression of a solid spherical ball with a diameter of 200-μm to form a dense core with an areal density of ˜0.07 g/cm2 was induced by a laser-driven spherically converging shock wave. Converging shock compression is more hydrodynamically stable compared to shell implosion, while a hot spot cannot be generated with a solid ball target. Solid ball compression is preferable also for compressing an external magnetic field to collimate the REB to the fuel core, due to the relatively small magnetic Reynolds number of the shock compressed region. To meet the third requirement, we have generated a strong kilo-tesla magnetic field using a laser-driven capacitor-coil target. The strength and time history of the magnetic field were characterized with proton deflectometry and a B-dot probe. Guidance of the REB using a 0.6-kT field in a planar geometry has been demonstrated at the LULI 2000 laser facility. In a realistic FI scenario, a magnetic mirror is formed between the REB generation point and the fuel core. The effects of the strong magnetic field on not only REB transport but also plasma compression were studied using numerical simulations. According to the transport calculations, the heating efficiency can be improved from 0.4% to 4% by the GEKKO and LFEX laser system by meeting the three requirements described above. This efficiency is scalable to 10% of the heating efficiency by increasing the areal density of the fuel core.

  17. Fast ignition realization experiment with high-contrast kilo-joule peta-watt LFEX laser and strong external magnetic field

    SciTech Connect

    Fujioka, Shinsuke Arikawa, Yasunobu; Kojima, Sadaoki; Nagatomo, Hideo; Lee, Seung Ho; Morace, Alessio; Vaisseau, Xavier; Sakata, Shohei; Abe, Yuki; Matsuo, Kazuki; Farley Law, King Fai; Tosaki, Shota; Yogo, Akifumi; Shigemori, Keisuke; Hironaka, Yoichiro; Fujimoto, Yasushi; Yamanoi, Kohei; Norimatsu, Takayoshi; Tokita, Shigeki; Nakata, Yoshiki; and others

    2016-05-15

    by imploding plasma. Following the above improvements, conversion of 13% of the LFEX laser energy to a low energy portion of the REB, whose slope temperature is 0.7 MeV, which is close to the ponderomotive scaling value, was achieved. To meet the second requirement, the compression of a solid spherical ball with a diameter of 200-μm to form a dense core with an areal density of ∼0.07 g/cm{sup 2} was induced by a laser-driven spherically converging shock wave. Converging shock compression is more hydrodynamically stable compared to shell implosion, while a hot spot cannot be generated with a solid ball target. Solid ball compression is preferable also for compressing an external magnetic field to collimate the REB to the fuel core, due to the relatively small magnetic Reynolds number of the shock compressed region. To meet the third requirement, we have generated a strong kilo-tesla magnetic field using a laser-driven capacitor-coil target. The strength and time history of the magnetic field were characterized with proton deflectometry and a B-dot probe. Guidance of the REB using a 0.6-kT field in a planar geometry has been demonstrated at the LULI 2000 laser facility. In a realistic FI scenario, a magnetic mirror is formed between the REB generation point and the fuel core. The effects of the strong magnetic field on not only REB transport but also plasma compression were studied using numerical simulations. According to the transport calculations, the heating efficiency can be improved from 0.4% to 4% by the GEKKO and LFEX laser system by meeting the three requirements described above. This efficiency is scalable to 10% of the heating efficiency by increasing the areal density of the fuel core.

  18. Photospheric magnetic fields

    NASA Technical Reports Server (NTRS)

    Howard, R.

    1972-01-01

    Knowledge on the nature of magnetic fields on the solar surface is reviewed. At least a large part of the magnetic flux in the solar surface is confined to small bundles of lines of force within which the field strength is of the order of 500 gauss. Magnetic fields are closely associated with all types of solar activity. Magnetic flux appears at the surface at the clearly defined birth or regeneration of activity of an active region. As the region ages, the magnetic flux migrates to form large-scale patterns and the polar fields. Some manifestations of the large-scale distribution are discussed.

  19. A Stable, Accurate Methodology for High Mach Number, Strong Magnetic Field MHD Turbulence with Adaptive Mesh Refinement: Resolution and Refinement Studies

    NASA Astrophysics Data System (ADS)

    Li, Pak Shing; Martin, Daniel F.; Klein, Richard I.; McKee, Christopher F.

    2012-02-01

    Performing a stable, long-duration simulation of driven MHD turbulence with a high thermal Mach number and a strong initial magnetic field is a challenge to high-order Godunov ideal MHD schemes because of the difficulty in guaranteeing positivity of the density and pressure. We have implemented a robust combination of reconstruction schemes, Riemann solvers, limiters, and constrained transport electromotive force averaging schemes that can meet this challenge, and using this strategy, we have developed a new adaptive mesh refinement (AMR) MHD module of the ORION2 code. We investigate the effects of AMR on several statistical properties of a turbulent ideal MHD system with a thermal Mach number of 10 and a plasma β0 of 0.1 as initial conditions; our code is shown to be stable for simulations with higher Mach numbers ({{\\cal M}_rms}= 17.3) and smaller plasma beta (β0 = 0.0067) as well. Our results show that the quality of the turbulence simulation is generally related to the volume-averaged refinement. Our AMR simulations show that the turbulent dissipation coefficient for supersonic MHD turbulence is about 0.5, in agreement with unigrid simulations.

  20. A STABLE, ACCURATE METHODOLOGY FOR HIGH MACH NUMBER, STRONG MAGNETIC FIELD MHD TURBULENCE WITH ADAPTIVE MESH REFINEMENT: RESOLUTION AND REFINEMENT STUDIES

    SciTech Connect

    Li, Pak Shing; Klein, Richard I.; Martin, Daniel F.; McKee, Christopher F. E-mail: klein@astron.berkeley.edu E-mail: cmckee@astro.berkeley.edu

    2012-02-01

    Performing a stable, long-duration simulation of driven MHD turbulence with a high thermal Mach number and a strong initial magnetic field is a challenge to high-order Godunov ideal MHD schemes because of the difficulty in guaranteeing positivity of the density and pressure. We have implemented a robust combination of reconstruction schemes, Riemann solvers, limiters, and constrained transport electromotive force averaging schemes that can meet this challenge, and using this strategy, we have developed a new adaptive mesh refinement (AMR) MHD module of the ORION2 code. We investigate the effects of AMR on several statistical properties of a turbulent ideal MHD system with a thermal Mach number of 10 and a plasma {beta}{sub 0} of 0.1 as initial conditions; our code is shown to be stable for simulations with higher Mach numbers (M{sub rms}= 17.3) and smaller plasma beta ({beta}{sub 0} = 0.0067) as well. Our results show that the quality of the turbulence simulation is generally related to the volume-averaged refinement. Our AMR simulations show that the turbulent dissipation coefficient for supersonic MHD turbulence is about 0.5, in agreement with unigrid simulations.

  1. Cyclotron resonance cooling by strong laser field

    SciTech Connect

    Tagcuhi, Toshihiro; Mima, Kunioka

    1995-12-31

    Reduction of energy spread of electron beam is very important to increase a total output radiation power in free electron lasers. Although several cooling systems of particle beams such as a stochastic cooling are successfully operated in the accelerator physics, these cooling mechanisms are very slow and they are only applicable to high energy charged particle beams of ring accelerators. We propose here a new concept of laser cooling system by means of cyclotron resonance. Electrons being in cyclotron motion under a strong magnetic field can resonate with circular polarized electromagnetic field, and the resonance take place selectively depending on the velocity of the electrons. If cyclotron frequency of electrons is equal to the frequency of the electromagnetic field, they absorb the electromagnetic field energy strongly, but the other electrons remain unchanged. The absorbed energy will be converted to transverse kinetic energy, and the energy will be dumped into the radiation energy through bremastrahlung. To build a cooling system, we must use two laser beams, where one of them is counter-propagating and the other is co-propagating with electron beam. When the frequency of the counter-propagating laser is tuned with the cyclotron frequency of fast electrons and the co-propagating laser is tuned with the cyclotron frequency of slow electrons, the energy of two groups will approach and the cooling will be achieved. We solve relativistic motions of electrons with relativistic radiation dumping force, and estimate the cooling rate of this mechanism. We will report optimum parameters for the electron beam cooling system for free electron lasers.

  2. Fast Ignition Realization Experiment with High-Contrast Kilo-Joule Peta-Watt Laser ``LFEX'' and Strong External Magnetic Field

    NASA Astrophysics Data System (ADS)

    Fujioka, Shinsuke

    2015-11-01

    We report on progresses of the Fast Ignition Realization Experiment (FIREX) project that has been curried out at the Institute of Laser Engineering to assess the feasibility of high density core heating with a high-power, short-pulse laser including the construction of the Kilo-Joule, Petawatt class LFEX laser system. Our recent studies identify three scientific challenges to achieve high heating efficiency in the fast ignition (FI) scheme with the current GEKKO and LFEX laser systems: (i) control of energy distribution of relativistic electron beam (REB), (ii) guiding and focusing of REB to a fuel core, and (iii) formation of a high areal-density core. The control of the electron energy distribution has been experimentally confirmed by improving the intensity contrast of the LFEX laser up to >109 and an ultra-high contrast of 1011 with a plasma mirror. After the contrast improvement, 50% of the total REB energy is carried by a low energy component of the REB, which slope temperature is close to the ponderomotive scaling value (~ 1 MeV). To guide the electron beam, we apply strong external magnetic field to the REB transport region. Guiding of the REB by 0.6 kT field in a planar geometry has already been demonstrated at LULI 2000 laser facility in a collaborative experiment lead by CELIA-Univ. Bordeaux. Considering more realistic FI scenario, we have performed a similar experiment using the Kilo-Joule LFEX laser to study the effect of guiding and magnetic mirror on the electron beam. A high density core of a laser-imploded 200 μm-diameter solid CD ball was radiographed with picosecond LFEX-produced K-alpha backlighter. Comparisons of the experimental results and integrated simulations using hydrodynamic and electron transport codes suggest that 10% of the efficiency can be achievable with the current GEKKO and LFEX laser system with the success of the above challenges. This work is supported by NIFS (Japan), MEXT/JSPS KAKENHI (Japan), JSPS Fellowship (Japan), ANR

  3. Laser propagation and soliton generation in strongly magnetized plasmas

    SciTech Connect

    Feng, W.; Li, J. Q.; Kishimoto, Y.

    2016-03-15

    The propagation characteristics of various laser modes with different polarization, as well as the soliton generation in strongly magnetized plasmas are studied numerically through one-dimensional (1D) particle-in-cell (PIC) simulations and analytically by solving the laser wave equation. PIC simulations show that the laser heating efficiency substantially depends on the magnetic field strength, the propagation modes of the laser pulse and their intensities. Generally, large amplitude laser can efficiently heat the plasma with strong magnetic field. Theoretical analyses on the linear propagation of the laser pulse in both under-dense and over-dense magnetized plasmas are well confirmed by the numerical observations. Most interestingly, it is found that a standing or moving soliton with frequency lower than the laser frequency is generated in certain magnetic field strength and laser intensity range, which can greatly enhance the laser heating efficiency. The range of magnetic field strength for the right-hand circularly polarized (RCP) soliton formation with high and low frequencies is identified by solving the soliton equations including the contribution of ion's motion and the finite temperature effects under the quasi-neutral approximation. In the limit of immobile ions, the RCP soliton tends to be peaked and stronger as the magnetic field increases, while the enhanced soliton becomes broader as the temperature increases. These findings in 1D model are well validated by 2D simulations.

  4. Magnetic Fields in Stars

    NASA Astrophysics Data System (ADS)

    Landstreet, J.; Murdin, P.

    2000-11-01

    Magnetism—the force that deflects the needle of a compass—and magnetic fields have been found in some hundreds of stars during the past 50 yr. Magnetic fields have been detected in T Tauri stars and other pre-main-sequence stars, several types of main sequence stars, white dwarfs and neutron stars. We now know a number of methods by which such magnetic fields may be detected, we are in the proces...

  5. Organic magnetic field sensor

    DOEpatents

    McCamey, Dane; Boehme, Christoph

    2017-01-24

    An organic, spin-dependent magnetic field sensor (10) includes an active stack (12) having an organic material with a spin-dependence. The sensor (10) also includes a back electrical contact (14) electrically coupled to a back of the active stack (12) and a front electrical contact (16) electrically coupled to a front of the active stack (12). A magnetic field generator (18) is oriented so as to provide an oscillating magnetic field which penetrates the active stack (12).

  6. Superhorizon magnetic fields

    NASA Astrophysics Data System (ADS)

    Campanelli, Leonardo

    2016-03-01

    We analyze the evolution of superhorizon-scale magnetic fields from the end of inflation till today. Whatever is the mechanism responsible for their generation during inflation, we find that a given magnetic mode with wave number k evolves, after inflation, according to the values of k ηe , nk , and Ωk , where ηe is the conformal time at the end of inflation, nk is the number density spectrum of inflation-produced photons, and Ωk is the phase difference between the two Bogoliubov coefficients which characterize the state of that mode at the end of inflation. For any realistic inflationary magnetogenesis scenario, we find that nk-1≪|k ηe|≪1 , and three evolutionary scenarios are possible: (i) |Ωk∓π |=O (1 ) , in which case the evolution of the magnetic spectrum Bk(η ) is adiabatic, a2Bk(η )=const , with a being the expansion parameter; (ii) |Ωk∓π |≪|k ηe| , in which case the evolution is superadiabatic, a2Bk(η )∝η ; (iii) |k ηe|≪|Ωk∓π |≪1 or |k ηe|˜|Ωk∓π |≪1 , in which case an early phase of adiabatic evolution is followed, after a time η⋆˜|Ωk∓π |/k , by a superadiabatic evolution. Once a given mode reenters the horizon, it remains frozen into the plasma and then evolves adiabatically till today. As a corollary of our results, we find that inflation-generated magnetic fields evolve adiabatically on all scales and for all times in conformal-invariant free Maxwell theory, while they evolve superadiabatically after inflation on superhorizon scales in the nonconformal-invariant Ratra model, where the inflaton is kinematically coupled to the electromagnetic field. The latter result supports and, somehow, clarifies our recent claim that the Ratra model can account for the presence of cosmic magnetic fields without suffering from both backreaction and strong-coupling problems.

  7. Understanding strongly coupling magnetism from holographic duality

    NASA Astrophysics Data System (ADS)

    Cai, Rong-Gen; Yang, Run-Qiu

    2016-07-01

    The unusual magnetic materials are significant in both science and technology. However, because of the strongly correlated effects, it is difficult to understand their novel properties from theoretical aspects. Holographic duality offers a new approach to understanding such systems from gravity side. This paper will give a brief review of our recent works on the applications of holographic duality in understanding unusual magnetic materials. Some quantitative comparision between holographic results and experimental data will be shown and some predictions from holographic duality models will be discussed.

  8. Mass-radius relation of strongly magnetized white dwarfs

    NASA Astrophysics Data System (ADS)

    Bera, Prasanta; Bhattacharya, Dipankar

    2016-07-01

    We study the strongly magnetized white dwarf configurations in a self-consistent manner as a progenitor of the over-luminous type-Ia supernovae. We compute static equilibria of white dwarf stars containing a strong magnetic field and present the modification of white dwarf mass-radius relation caused by the magnetic field. From a static equilibrium study, we find that a maximum white dwarf mass of about 1.9 M_{⊙} may be supported if the interior poloidal field is as strong as approximately 10^{10} T. On the other hand, if the field is purely toroidal the maximum mass can be more than 5 M_⊙. All these modifications are mainly from the presence of Lorenz force. The effects of i) modification of equation of state due to Landau quantization ii) electrostatic interaction due to ions, ii) general relativistic calculation on the stellar structure and, iii) field geometry are also considered. These strongly magnetised configurations are sensitive to magnetic instabilities where the perturbations grow at the corresponding Alfven time scales.

  9. Mass-Radius Relation of Strongly Magnetized White Dwarfs

    NASA Astrophysics Data System (ADS)

    Bera, P.; Bhattacharya, D.

    2017-03-01

    We study the strongly magnetized white dwarf configurations in a self-consistent manner as a progenitor of the over-luminous type-Ia supernovae. We compute static equilibria of white dwarf stars containing a strong magnetic field and present the modification of the white dwarf mass-radius relation caused by the magnetic field. From a static equilibrium study, we find that a maximum white dwarf mass of about 1.9 M⊙ may be supported if the interior poloidal field is as strong as approximately 1010 T. On the other hand if the field is purely toroidal the maximum mass can be more than 5 M⊙. All these modifications are mainly from the presence of the Lorenz force. The effects of i) modification of the equation of state due to Landau quantization, ii) electrostatic interaction due to ions, iii) general relativistic calculation on the stellar structure and, iv) field geometry are also considered. These strongly magnetised configurations are sensitive to magnetic instabilities where the perturbations grow at the corresponding Alfven time scales.

  10. Anomalous aspects of magnetosheath flow and of the shape and oscillations of the magnetopause during an interval of strongly northward interplanetary magnetic field

    NASA Technical Reports Server (NTRS)

    Chen, Sheng-Hsien; Kivelson, Margaret G.; Gosling, Jack T.; Walker, Raymond T.; Lazarus, Allan J.

    1992-01-01

    On 15 Feb. 1978, the orientation of the interplanetary magnetic field (IMF) remained steadily northward for more than 12 hours. The ISEE 1 and 2 spacecraft were located near apogee on the dawn side flank of the magnetotail. IMP 8 was almost symmetrically located in the magnetosheath on the dusk flank and IMP 7 was upstream in the solar wind. Using plasma and magnetic field data, we show the following: (1) the magnetosheath flow speed on the flanks of the magnetotail steadily exceeded the solar wind speed by 20 percent; (2) surface waves with approximately a 5-min period and very non-sinusoidal waveform were persistently present on the dawn magnetopause and waves of similar period were present in the dusk magnetosheath; and (3) the magnetotail ceased to flare at an antisunward distance of 15 R(sub E). We propose that the acceleration of the magnetosheath flow is achieved by magnetic tension in the draped field configuration for northward IMF and that the reduction of tail flaring is consistent with a decreased amount of open magnetic flux and a larger standoff distance of the subsolar magnetopause. Results of a three-dimensional magnetohydrodynamic simulation support this phenomenological model.

  11. Electron-positron pair equilibrium in strongly magnetized plasmas

    SciTech Connect

    Harding, A.K.

    1984-11-01

    Steady states of thermal electron-positron pair plasmas at mildly relativistic temperatures and in strong magnetic fields are investigated. The pair density in steady-state equilibrium, where pair production balances annihilation, is found as a function of temperature, magnetic field strength and source size, by a numerical calculation which includes pair production attenuation and Compton scattering of the photons. It is found that there is a maximum pair density for each value of temperature and field strength, and also a source size above which optically thin equilibrium states do not exist. (ESA)

  12. Spin equilibrium in strongly magnetized accreting stars

    NASA Astrophysics Data System (ADS)

    D'Angelo, C. R.

    2017-09-01

    Strongly magnetized accreting stars are often hypothesized to be in 'spin equilibrium' with their surrounding accretion flows, which requires that the accretion rate changes more slowly than it takes the star to reach spin equilibrium. This is not true for most magnetically accreting stars, which have strongly variable accretion outbursts on time-scales much shorter than the time it would take to reach spin equilibrium. This paper examines how accretion outbursts affect the time a star takes to reach spin equilibrium and its final equilibrium spin period. I consider several different models for angular momentum loss - either carried away in an outflow, lost to a stellar wind, or transferred back to the accretion disc (the 'trapped disc'). For transient sources, the outflow scenario leads to significantly longer times to reach spin equilibrium (∼10 ×), and shorter equilibrium spin periods than would be expected from spin equilibrium arguments, while the 'trapped disc' does not. The results suggest that disc trapping plays a significant role in the spin evolution of strongly magnetic stars, with some caveats for young stellar objects.

  13. Strong Landau-quantization effects in high-magnetic-field superconductivity of a two-dimensional multiple-band metal near the Lifshitz transition

    DOE PAGES

    Song, Kok Wee; Koshelev, Alexei E.

    2017-05-04

    We investigate the onset of superconductivity in a magnetic field for a clean two-dimensional multiple-band superconductor in the vicinity of the Lifshitz transition when one of the bands is very shallow. Due to the small number of carriers in this band, the quasiclassical Werthamer-Helfand approximation breaks down and Landau quantization has to be taken into account. We found that the transition temperature TC2(H) has giant oscillations and is resonantly enhanced at the magnetic fields corresponding to the matching of the chemical potential with the Landau levels in the shallow band. This enhancement is especially pronounced for the lowest Landau level.more » As a consequence, the reentrant superconducting regions in the temperature-field phase diagram emerge at low temperatures near the magnetic fields at which the shallow-band Landau levels cross the chemical potential. The specific behavior depends on the relative strength of the intraband and interband pairing interactions and the reentrance is most pronounced in the purely interband coupling scenario. The reentrant behavior is suppressed by the Zeeman spin splitting in the shallow band; the separated regions disappear already for very small spin-splitting factors. On the other hand, the reentrance is restored in the resonance cases when the spin-splitting energy exactly matches the separation between the Landau levels. As a result, the predicted behavior may be realized in the gate-tuned FeSe monolayer.« less

  14. Strong Landau-quantization effects in high-magnetic-field superconductivity of a two-dimensional multiple-band metal near the Lifshitz transition

    NASA Astrophysics Data System (ADS)

    Song, Kok Wee; Koshelev, Alexei E.

    2017-05-01

    We investigate the onset of superconductivity in a magnetic field for a clean two-dimensional multiple-band superconductor in the vicinity of the Lifshitz transition when one of the bands is very shallow. Due to the small number of carriers in this band, the quasiclassical Werthamer-Helfand approximation breaks down and Landau quantization has to be taken into account. We found that the transition temperature TC 2(H ) has giant oscillations and is resonantly enhanced at the magnetic fields corresponding to the matching of the chemical potential with the Landau levels in the shallow band. This enhancement is especially pronounced for the lowest Landau level. As a consequence, the reentrant superconducting regions in the temperature-field phase diagram emerge at low temperatures near the magnetic fields at which the shallow-band Landau levels cross the chemical potential. The specific behavior depends on the relative strength of the intraband and interband pairing interactions and the reentrance is most pronounced in the purely interband coupling scenario. The reentrant behavior is suppressed by the Zeeman spin splitting in the shallow band; the separated regions disappear already for very small spin-splitting factors. On the other hand, the reentrance is restored in the resonance cases when the spin-splitting energy exactly matches the separation between the Landau levels. The predicted behavior may be realized in the gate-tuned FeSe monolayer.

  15. Strongly anomalous diffusion in sheared magnetic configurations

    SciTech Connect

    Vanden Eijnden, E.; Balescu, R.

    1996-03-01

    The statistical behavior of magnetic lines in a sheared magnetic configuration with reference surface {ital x}=0 is investigated within the framework of the kinetic theory. A Liouville equation is associated with the equations of motion of the stochastic magnetic lines. After averaging over an ensemble of realizations, it yields a convection-diffusion equation within the quasilinear approximation. The diffusion coefficients are space dependent and peaked around the reference surface {ital x}=0. Due to the shear, the diffusion of lines away from the reference surface is slowed down. The behavior of the lines is asymptotically strongly non-Gaussian. The reference surface acts like an attractor around which the magnetic lines spread with an effective subdiffusive behavior. Comparison is also made with more usual treatments based on the study of the first two moments equations. For sheared systems, it is explicitly shown that the Corrsin approximation assumed in the latter approach is no longer valid. It is also concluded that the diffusion coefficients cannot be derived from the mean square displacement of the magnetic lines in an inhomogeneous medium. {copyright} {ital 1996 American Institute of Physics.}

  16. Magnetic fields during galaxy mergers

    NASA Astrophysics Data System (ADS)

    Rodenbeck, Kai; Schleicher, Dominik R. G.

    2016-09-01

    Galaxy mergers are expected to play a central role for the evolution of galaxies and may have a strong effect on their magnetic fields. We present the first grid-based 3D magnetohydrodynamical simulations investigating the evolution of magnetic fields during merger events. For this purpose, we employed a simplified model considering the merger event of magnetized gaseous disks in the absence of stellar feedback and without a stellar or dark matter component. We show that our model naturally leads to the production of two peaks in the evolution of the average magnetic field strength within 5 kpc, within 25 kpc, and on scales in between 5 and 25 kpc. The latter is consistent with the peak in the magnetic field strength previously reported in a merger sequence of observed galaxies. We show that the peak on the galactic scale and in the outer regions is most likely due to geometrical effects, as the core of one galaxy enters the outskirts of the other one. In addition, the magnetic field within the central ~5 kpc is physically enhanced, which reflects the enhancement in density that is due to efficient angular momentum transport. We conclude that high-resolution observations of the central regions will be particularly relevant for probing the evolution of magnetic field structures during merger events.

  17. Neutrino emissivity from e sup minus synchrotron and e sup minus e+ annihilation processes in a strong magnetic field: General formalism and nonrelativistic limit

    SciTech Connect

    Kaminker, A.D.; Levenfish, K.P.; Yakovlev, D.G. ); Amsterdamski, P.; Haensel, P. )

    1992-10-15

    A general formalism is developed for calculating the neutrino emissivities of synchrotron and {ital e}{sup {minus}}{ital e+} annihilation radiations in a plasma in the presence of a large magnetic field {ital B}{similar to}10{sup 12}--10{sup 14} G. As a first step, the formalism is used to calculate the synchrotron and annihilation radiations from a nonrelativistic electron plasma (density {rho}{approx lt}10{sup 6} g cm{sup {minus}3}, temperature {ital T}{approx lt}6{times}10{sup 9} K) including the cases of nondegenerate and degenerate electrons, and of quantizing and nonquantizing magnetic fields. We conclude that these processes can be important for neutrino production in a hot plasma of neutron star envelopes.

  18. Saturated-absorption spectroscopy revisited: atomic transitions in strong magnetic fields (>20  mT) with a micrometer-thin cell.

    PubMed

    Sargsyan, A; Tonoyan, A; Mirzoyan, R; Sarkisyan, D; Wojciechowski, A M; Stabrawa, A; Gawlik, W

    2014-04-15

    The existence of crossover resonances makes saturated-absorption (SA) spectra very complicated when external magnetic field B is applied. It is demonstrated for the first time, to the best of our knowledge, that the use of micrometric-thin cells (MTCs, L≈40  μm) allows application of SA for quantitative studies of frequency splitting and shifts of the Rb atomic transitions in a wide range of external magnetic fields, from 0.2 up to 6 kG (20-600 mT). We compare the SA spectra obtained with the MTC with those obtained with other techniques and present applications for optical magnetometry with micrometer spatial resolution and a broadly tunable optical frequency lock.

  19. Intersubband terahertz transitions in Landau level system of cascade GaAs/AlGaAs quantum well structures in strong tilted magnetic field

    PubMed Central

    2012-01-01

    The tunable terahertz intersubband Landau level transitions in resonant tunneling cascade quantum well structures are considered. The way of lifting the selection rule forbidding the inter-Landau level terahertz transitions of interest by applying a magnetic field tilted with respect to the structure layers is proposed. The importance of asymmetric structure design to achieve considerable values of transition dipole matrix elements is demonstrated. PMID:22937922

  20. Magnetic field generation by rotating black holes

    NASA Technical Reports Server (NTRS)

    Leahy, D. A.; Vilenkin, A.

    1981-01-01

    A new mechanism of cosmic magnetic field generation is discussed. Neutrinos asymmetrically emitted by rotating black holes scatter on protons and produce a proton current which generates the magnetic field. It is shown that this mechanism can in principle produce a seed field sufficiently strong to account for present galactic fields.

  1. CLASSSTRONG: Classical simulations of strong field processes

    NASA Astrophysics Data System (ADS)

    Ciappina, M. F.; Pérez-Hernández, J. A.; Lewenstein, M.

    2014-01-01

    A set of Mathematica functions is presented to model classically two of the most important processes in strong field physics, namely high-order harmonic generation (HHG) and above-threshold ionization (ATI). Our approach is based on the numerical solution of the Newton-Lorentz equation of an electron moving on an electric field and takes advantage of the symbolic languages features and graphical power of Mathematica. Like in the Strong Field Approximation (SFA), the effects of atomic potential on the motion of electron in the laser field are neglected. The SFA was proven to be an essential tool in strong field physics in the sense that it is able to predict with great precision the harmonic (in the HHG) and energy (in the ATI) limits. We have extended substantially the conventional classical simulations, where the electric field is only dependent on time, including spatial nonhomogeneous fields and spatial and temporal synthesized fields. Spatial nonhomogeneous fields appear when metal nanosystems interact with strong and short laser pulses and temporal synthesized fields are routinely generated in attosecond laboratories around the world. Temporal and spatial synthesized fields have received special attention nowadays because they would allow to exceed considerably the conventional harmonic and electron energy frontiers. Classical simulations are an invaluable tool to explore exhaustively the parameters domain at a cheap computational cost, before massive quantum mechanical calculations, absolutely indispensable for the detailed analysis, are performed.

  2. Deformation of Water by a Magnetic Field

    ERIC Educational Resources Information Center

    Chen, Zijun; Dahlberg, E. Dan

    2011-01-01

    After the discovery that superconducting magnets could levitate diamagnetic objects, researchers became interested in measuring the repulsion of diamagnetic fluids in strong magnetic fields, which was given the name "The Moses Effect." Both for the levitation experiments and the quantitative studies on liquids, the large magnetic fields necessary…

  3. Deformation of Water by a Magnetic Field

    ERIC Educational Resources Information Center

    Chen, Zijun; Dahlberg, E. Dan

    2011-01-01

    After the discovery that superconducting magnets could levitate diamagnetic objects, researchers became interested in measuring the repulsion of diamagnetic fluids in strong magnetic fields, which was given the name "The Moses Effect." Both for the levitation experiments and the quantitative studies on liquids, the large magnetic fields necessary…

  4. Magnetic fields in spiral galaxies

    NASA Astrophysics Data System (ADS)

    Chiba, Masashi

    The magnetic-field characteristics in spiral galaxies are investigated, with emphasis on the Milky Way. The dynamo theory is considered, and axisymmetric spiral (ASS) and bisymmetric spiral (BSS) magnetic fields are analyzed. Toroidal and poloidal magnetic fields are discussed.

  5. Magnetic field effects on microwave absorbing materials

    NASA Technical Reports Server (NTRS)

    Goldberg, Ira; Hollingsworth, Charles S.; Mckinney, Ted M.

    1991-01-01

    The objective of this program was to gather information to formulate a microwave absorber that can work in the presence of strong constant direct current (DC) magnetic fields. The program was conducted in four steps. The first step was to investigate the electrical and magnetic properties of magnetic and ferrite microwave absorbers in the presence of strong magnetic fields. This included both experimental measurements and a literature survey of properties that may be applicable to finding an appropriate absorbing material. The second step was to identify those material properties that will produce desirable absorptive properties in the presence of intense magnetic fields and determine the range of magnetic field in which the absorbers remain effective. The third step was to establish ferrite absorber designs that will produce low reflection and adequate absorption in the presence of intense inhomogeneous static magnetic fields. The fourth and final step was to prepare and test samples of such magnetic microwave absorbers if such designs seem practical.

  6. Magnetic field dosimeter development

    SciTech Connect

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

    1980-09-01

    In recent years there has been increased concern over potential health hazards related to exposure of personnel to magnetic fields. If exposure standards are to be established, then a means for measuring magnetic field dose must be available. To meet this need, the Department of Energy has funded development of prototype dosimeters at the Battelle Pacific Northwest Laboratory. This manual reviews the principle of operation of the dosimeter and also contains step-by-step instructions for its operation.

  7. Magnetosheath magnetic field variability

    NASA Technical Reports Server (NTRS)

    Sibeck, D. G.

    1994-01-01

    A case study using simulations IRM and CCE observations demonstrates that transient magnetospheric events correspond to pressure pulses in the magnetosheath, inward bow shock motion, and magnetopause compression. Statistical surveys indicate that the magnetosheath magnetic field orientation rarely remains constant during periods of magnetopause and bow shock motion (both characterized by periods of 1 to 10 min). There is no tendency for bow shock motion to occur for southward interplanetary magnetic field (IMF) orientations.

  8. Magnetic flux noise in strongly anisotropic superconductors

    NASA Astrophysics Data System (ADS)

    Ashkenazy, V. D.; Jung, G.; Shapiro, B. Ya.

    1995-04-01

    Magnetic noise due to thermally activated movements of flux vortices has been calculated taking into account fluctuations modes of nonrigid vortices. It has been shown that at low frequencies, below the crossover frequency, the noise spectrum of a layered superconductor is identical to that of a continuous material. Three regimes of spectral behavior, lnω, ω-1/2, and ω-3/2, have been predicted to be present in this frequency range. Characteristic frequencies separating different regimes depend on the geometry of the flux pickup loop. At high frequencies, above the crossover frequency, bending of vortices leads to a Lorentzian shape of noise spectra. The value of the crossover frquency is not influenced by the particularities of the flux-measuring arrangement and depends only on the material properties and applied magnetic field.

  9. Solar Wind Magnetic Fields

    NASA Technical Reports Server (NTRS)

    Smith, E. J.

    1995-01-01

    The magnetic fields originate as coronal fields that are converted into space by the supersonic, infinitely conducting, solar wind. On average, the sun's rotation causes the field to wind up and form an Archimedes Spiral. However, the field direction changes almost continuously on a variety of scales and the irregular nature of these changes is often interpreted as evidence that the solar wind flow is turbulent.

  10. Solar Wind Magnetic Fields

    NASA Technical Reports Server (NTRS)

    Smith, E. J.

    1995-01-01

    The magnetic fields originate as coronal fields that are converted into space by the supersonic, infinitely conducting, solar wind. On average, the sun's rotation causes the field to wind up and form an Archimedes Spiral. However, the field direction changes almost continuously on a variety of scales and the irregular nature of these changes is often interpreted as evidence that the solar wind flow is turbulent.

  11. Magnetic Field Illuminated

    NASA Image and Video Library

    2016-06-16

    Each day NASA solar scientists produce overlays (in white lines) that show their estimation of how the magnetic field lines above the sun are configured (June16, 2016). In the video clip we show the sun in a wavelength of extreme ultraviolet light, then reveal the magnetic field line configuration in the same wavelength. Notice how the lines are tightly bundled near the lighter-toned active regions, which are magnetically intense regions. The magnetic lines from the darker areas, called coronal holes, open out into space and the extended lines show that. Our magnetically active sun is a dynamic body that changes all the time. Movie are also available at the Photojournal. http://photojournal.jpl.nasa.gov/catalog/PIA20881

  12. Strong permanent magnet-assisted electromagnetic undulator

    DOEpatents

    Halbach, Klaus

    1988-01-01

    This invention discloses an improved undulator comprising a plurality of electromagnet poles located along opposite sides of a particle beam axis with alternate north and south poles on each side of the beam to cause the beam to wiggle or undulate as it travels generally along the beam axis and permanent magnets spaced adjacent the electromagnetic poles on each side of the axis of said particle beam in an orientation sufficient to reduce the saturation of the electromagnet poles whereby the field strength of the electromagnet poles can be increased beyond the normal saturation levels of the electromagnetic poles.

  13. Semimetallization of dielectrics in strong optical fields

    NASA Astrophysics Data System (ADS)

    Kwon, Ojoon; Paasch-Colberg, Tim; Apalkov, Vadym; Kim, Bum-Kyu; Kim, Ju-Jin; Stockman, Mark I.; Kim, D.

    2016-02-01

    At the heart of ever growing demands for faster signal processing is ultrafast charge transport and control by electromagnetic fields in semiconductors. Intense optical fields have opened fascinating avenues for new phenomena and applications in solids. Because the period of optical fields is on the order of a femtosecond, the current switching and its control by an optical field may pave a way to petahertz optoelectronic devices. Lately, a reversible semimetallization in fused silica on a femtosecond time scale by using a few-cycle strong field (~1 V/Å) is manifested. The strong Wannier-Stark localization and Zener-type tunneling were expected to drive this ultrafast semimetallization. Wider spread of this technology demands better understanding of whether the strong field behavior is universally similar for different dielectrics. Here we employ a carrier-envelope-phase stabilized, few-cycle strong optical field to drive the semimetallization in sapphire, calcium fluoride and quartz and to compare this phenomenon and show its remarkable similarity between them. The similarity in response of these materials, despite the distinguishable differences in their physical properties, suggests the universality of the physical picture explained by the localization of Wannier-Stark states. Our results may blaze a trail to PHz-rate optoelectronics.

  14. Semimetallization of dielectrics in strong optical fields

    DOE PAGES

    Kwon, Ojoon; Paasch-Colberg, Tim; Apalkov, Vadym; ...

    2016-02-18

    At the heart of ever growing demands for faster signal processing is ultrafast charge transport and control by electromagnetic fields in semiconductors. Intense optical fields have opened fascinating avenues for new phenomena and applications in solids. Because the period of optical fields is on the order of a femtosecond, the current switching and its control by an optical field may pave a way to petahertz optoelectronic devices. Lately, a reversible semimetallization in fused silica on a femtosecond time scale by using a few-cycle strong field (~1 V/Å) is manifested. The strong Wannier-Stark localization and Zener-type tunneling were expected to drivemore » this ultrafast semimetallization. Wider spread of this technology demands better understanding of whether the strong field behavior is universally similar for different dielectrics. Here we employ a carrier-envelope-phase stabilized, few-cycle strong optical field to drive the semimetallization in sapphire, calcium fluoride and quartz and to compare this phenomenon and show its remarkable similarity between them. The similarity in response of these materials, despite the distinguishable differences in their physical properties, suggests the universality of the physical picture explained by the localization of Wannier-Stark states. Lastly, our results may blaze a trail to PHz-rate optoelectronics.« less

  15. Semimetallization of dielectrics in strong optical fields

    SciTech Connect

    Kwon, Ojoon; Apalkov, Vadym; Kim, Bum -Kyu; Kim, Ju -Jin; Stockman, Mark I.; Kim, D.

    2016-02-18

    At the heart of ever growing demands for faster signal processing is ultrafast charge transport and control by electromagnetic fields in semiconductors. Intense optical fields have opened fascinating avenues for new phenomena and applications in solids. Because the period of optical fields is on the order of a femtosecond, the current switching and its control by an optical field may pave a way to petahertz optoelectronic devices. Lately, a reversible semimetallization in fused silica on a femtosecond time scale by using a few-cycle strong field (~1 V/Å) is manifested. The strong Wannier-Stark localization and Zener-type tunneling were expected to drive this ultrafast semimetallization. Wider spread of this technology demands better understanding of whether the strong field behavior is universally similar for different dielectrics. Here we employ a carrier-envelope-phase stabilized, few-cycle strong optical field to drive the semimetallization in sapphire, calcium fluoride and quartz and to compare this phenomenon and show its remarkable similarity between them. The similarity in response of these materials, despite the distinguishable differences in their physical properties, suggests the universality of the physical picture explained by the localization of Wannier-Stark states. Lastly, our results may blaze a trail to PHz-rate optoelectronics.

  16. Semimetallization of dielectrics in strong optical fields

    PubMed Central

    Kwon, Ojoon; Paasch-Colberg, Tim; Apalkov, Vadym; Kim, Bum-Kyu; Kim, Ju-Jin; Stockman, Mark I.; Kim, D.

    2016-01-01

    At the heart of ever growing demands for faster signal processing is ultrafast charge transport and control by electromagnetic fields in semiconductors. Intense optical fields have opened fascinating avenues for new phenomena and applications in solids. Because the period of optical fields is on the order of a femtosecond, the current switching and its control by an optical field may pave a way to petahertz optoelectronic devices. Lately, a reversible semimetallization in fused silica on a femtosecond time scale by using a few-cycle strong field (~1 V/Å) is manifested. The strong Wannier-Stark localization and Zener-type tunneling were expected to drive this ultrafast semimetallization. Wider spread of this technology demands better understanding of whether the strong field behavior is universally similar for different dielectrics. Here we employ a carrier-envelope-phase stabilized, few-cycle strong optical field to drive the semimetallization in sapphire, calcium fluoride and quartz and to compare this phenomenon and show its remarkable similarity between them. The similarity in response of these materials, despite the distinguishable differences in their physical properties, suggests the universality of the physical picture explained by the localization of Wannier-Stark states. Our results may blaze a trail to PHz-rate optoelectronics. PMID:26888147

  17. Molecules in Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Berdyugina, Svetlana

    2015-08-01

    Molecules probe cool matter in the Universe and various astrophysical objects. Their ability to sense magnetic fields provides new insights into magnetic properties of these objects. During the past fifteen years we have carried out a theoretical study of molecular magnetic effects such as the Zeeman, Paschen-Back and Hanle effects and their applications for inferring magnetic structures and spatial inhomogeneities on the Sun, cool stars, brown dwarfs, and exoplanets from molecular spectro-polarimetry (e.g., Berdyugina 2011). Here, we present an overview of this study and compare our theoretical predictions with recent laboratory measurements of magnetic properties of some molecules. We present also a new web-based tool to compute molecular magnetic effects and polarized spectra which is supported by the ERC Advanced Grant HotMol.

  18. Magnetic fields in spiral galaxies

    NASA Astrophysics Data System (ADS)

    Beck, Rainer

    2015-12-01

    Radio synchrotron emission, its polarization and Faraday rotation of the polarization angle are powerful tools to study the strength and structure of magnetic fields in galaxies. Unpolarized synchrotron emission traces isotropic turbulent fields which are strongest in spiral arms and bars (20-30 \\upmu G) and in central starburst regions (50-100 \\upmu G). Such fields are dynamically important; they affect gas flows and drive gas inflows in central regions. Polarized emission traces ordered fields, which can be regular or anisotropic turbulent, where the latter originates from isotropic turbulent fields by the action of compression or shear. The strongest ordered fields (10-15 \\upmu G) are generally found in interarm regions. In galaxies with strong density waves, ordered fields are also observed at the inner edges of spiral arms. Ordered fields with spiral patterns exist in grand-design, barred and flocculent galaxies and in central regions. Ordered fields in interacting galaxies have asymmetric distributions and are a tracer of past interactions between galaxies or with the intergalactic medium.—Faraday rotation measures of the diffuse polarized radio emission from galaxy disks reveal large-scale spiral patterns that can be described by the superposition of azimuthal modes; these are signatures of regular fields generated by mean-field dynamos. "Magnetic arms" between gaseous spiral arms may also be products of dynamo action, but need a stable spiral pattern to develop. Helically twisted field loops winding around spiral arms were found in two galaxies so far. Large-scale field reversals, like the one found in the Milky Way, could not yet be detected in external galaxies. In radio halos around edge-on galaxies, ordered magnetic fields with X-shaped patterns are observed. The origin and evolution of cosmic magnetic fields, in particular their first occurrence in young galaxies and their dynamical importance during galaxy evolution, will be studied with

  19. Transducer measures temperature differentials in presence of strong electromagnetic fields

    NASA Technical Reports Server (NTRS)

    1965-01-01

    Measurement of temperature rise of cooling water under pressure and in strong electromagnetic fields is accomplished by a transducer using a magnetically shielded thermocouple arrangement. The thermocouple junctions are immersed in oil to isolate them from electric currents in the water.

  20. Cluster Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Carilli, C. L.; Taylor, G. B.

    Magnetic fields in the intercluster medium have been measured using a variety of techniques, including studies of synchrotron relic and halo radio sources within clusters, studies of inverse Compton X-ray emission from clusters, surveys of Faraday rotation measures of polarized radio sources both within and behind clusters, and studies of cluster cold fronts in X-ray images. These measurements imply that most cluster atmospheres are substantially magnetized, with typical field strengths of order 1 μGauss with high areal filling factors out to Mpc radii. There is likely to be considerable variation in field strengths and topologies both within and between clusters, especially when comparing dynamically relaxed clusters to those that have recently undergone a merger. In some locations, such as the cores of cooling flow clusters, the magnetic fields reach levels of 10-40 μG and may be dynamically important. In all clusters the magnetic fields have a significant effect on energy transport in the intracluster medium. We also review current theories on the origin of cluster magnetic fields.

  1. Interaction of gravitational waves with strongly magnetized plasmas

    SciTech Connect

    Isliker, Heinz; Vlahos, Loukas; Sandberg, Ingmar

    2006-11-15

    We study the interaction of a gravitational wave (GW) with a plasma that is strongly magnetized. The GW is considered a small disturbance, and the plasma is modeled by the general relativistic analogue of the induction equation of ideal MHD and the single fluid equations. The equations are specified to two different cases, first to Cartesian coordinates and a constant background magnetic fields, and second to spherical coordinates together with a background magnetic field that decays with the inverse radial distance. The equations are derived without neglecting any of the nonlinear interaction terms, and the nonlinear equations are integrated numerically. We find that for strong magnetic fields of the order of 10{sup 15} G the GW excites electromagnetic plasma waves very close to the magnetosonic mode. The magnetic and electric field oscillations have very high amplitude, and a large amount of energy is absorbed from the GW by the electromagnetic oscillations, of the order of 10{sup 23} erg/cm{sup 3} in the case presented here, which, when assuming a relatively small volume in a star's magnetosphere as an interaction region, can yield a total energy of at least 10{sup 41} erg and may be up to 10{sup 43} erg. The absorbed energy is proportional to B{sub 0}{sup 2}, with B{sub 0} the background magnetic field. The energizing of the plasma takes place on fast time scales of the order of milliseconds. Our results imply that the GW-plasma interaction is an efficient and important mechanism in magnetar atmospheres, most prominently close to the star, and, under very favorable conditions though, it might even be the primary energizing mechanism behind giant flares.

  2. Magnetic Field Solver

    NASA Technical Reports Server (NTRS)

    Ilin, Andrew V.

    2006-01-01

    The Magnetic Field Solver computer program calculates the magnetic field generated by a group of collinear, cylindrical axisymmetric electromagnet coils. Given the current flowing in, and the number of turns, axial position, and axial and radial dimensions of each coil, the program calculates matrix coefficients for a finite-difference system of equations that approximates a two-dimensional partial differential equation for the magnetic potential contributed by the coil. The program iteratively solves these finite-difference equations by use of the modified incomplete Cholesky preconditioned-conjugate-gradient method. The total magnetic potential as a function of axial (z) and radial (r) position is then calculated as a sum of the magnetic potentials of the individual coils, using a high-accuracy interpolation scheme. Then the r and z components of the magnetic field as functions of r and z are calculated from the total magnetic potential by use of a high-accuracy finite-difference scheme. Notably, for the finite-difference calculations, the program generates nonuniform two-dimensional computational meshes from nonuniform one-dimensional meshes. Each mesh is generated in such a way as to minimize the numerical error for a benchmark one-dimensional magnetostatic problem.

  3. Strong localization effect in magnetic two-dimensional hole systems

    SciTech Connect

    Wurstbauer, U.; Knott, S.; Zolotaryov, A.; Hansen, W.; Schuh, D.; Wegscheider, W.

    2010-01-11

    We report an extensive study of the magnetotransport properties of magnetically doped two-dimensional hole systems. Inverted manganese modulation doped InAs quantum wells with localized manganese ions providing a magnetic moment of S=5/2 were grown by molecular beam epitaxy. Strong localization effect found in low-field magnetotransport measurements on these structures can either be modified by the manganese doping density or by tuning the two-dimensional hole density p via field effect. The data reveal that the ratio between p and manganese ions inside or in close vicinity to the channel enlarges the strong localization effect. Moreover, asymmetric broadening of the doping layer due to manganese segregation is significantly influenced by strain in the heterostructure.

  4. Strong localization effect in magnetic two-dimensional hole systems

    NASA Astrophysics Data System (ADS)

    Wurstbauer, U.; Knott, S.; Zolotaryov, A.; Schuh, D.; Hansen, W.; Wegscheider, W.

    2010-01-01

    We report an extensive study of the magnetotransport properties of magnetically doped two-dimensional hole systems. Inverted manganese modulation doped InAs quantum wells with localized manganese ions providing a magnetic moment of S=5/2 were grown by molecular beam epitaxy. Strong localization effect found in low-field magnetotransport measurements on these structures can either be modified by the manganese doping density or by tuning the two-dimensional hole density p via field effect. The data reveal that the ratio between p and manganese ions inside or in close vicinity to the channel enlarges the strong localization effect. Moreover, asymmetric broadening of the doping layer due to manganese segregation is significantly influenced by strain in the heterostructure.

  5. Stochastic dynamics of strongly-bound magnetic vortex pairs

    NASA Astrophysics Data System (ADS)

    Bondarenko, A. V.; Holmgren, E.; Koop, B. C.; Descamps, T.; Ivanov, B. A.; Korenivski, V.

    2017-05-01

    We demonstrate that strongly-bound spin-vortex pairs exhibit pronounced stochastic behaviour. Such dynamics is due to collective magnetization states originating from purely dipolar interactions between the vortices. The resulting thermal noise exhibits telegraph-like behaviour, with random switching between different oscillation regimes observable at room temperature. The noise in the system is further studied by varying the external field and observing the related changes in the frequency of switching and the probability for different magnetic states and regimes. Monte Carlo simulations are used to replicate and explain the experimental observations.

  6. Strong magnetization measured in the cool cores of galaxy clusters.

    PubMed

    Reiss, Ido; Keshet, Uri

    2014-08-15

    Tangential discontinuities, seen as x-ray edges known as cold fronts (CFs), are ubiquitous in cool-core galaxy clusters. We analyze all 17 deprojected CF thermal profiles found in the literature, including three new CFs we tentatively identify (in clusters A2204 and 2A0335). We discover small but significant thermal pressure drops below all nonmerger CFs, and argue that they arise from strong magnetic fields below and parallel to the discontinuity, carrying 10%-20% of the pressure. Such magnetization can stabilize the CFs, and explain the CF-radio minihalo connection.

  7. Propagation of intense laser pulses in strongly magnetized plasmas

    SciTech Connect

    Yang, X. H. Ge, Z. Y.; Xu, B. B.; Zhuo, H. B.; Ma, Y. Y.; Shao, F. Q.; Yu, W.; Xu, H.; Yu, M. Y.; Borghesi, M.

    2015-06-01

    Propagation of intense circularly polarized laser pulses in strongly magnetized inhomogeneous plasmas is investigated. It is shown that a left-hand circularly polarized laser pulse propagating up the density gradient of the plasma along the magnetic field is reflected at the left-cutoff density. However, a right-hand circularly polarized laser can penetrate up the density gradient deep into the plasma without cutoff or resonance and turbulently heat the electrons trapped in its wake. Results from particle-in-cell simulations are in good agreement with that from the theory.

  8. Development of a strong field helicon plasma source

    SciTech Connect

    Shinohara, Shunjiro; Mizokoshi, Hiroshi

    2006-03-15

    We developed a high-density helicon plasma source with a very strong field of up to 10 kG. Using a double-loop antenna wound around a quartz tube, 9.5 cm in inner diameter and 90 cm in axial length, initial plasmas with a high density more than 10{sup 13} cm{sup -3} were successfully produced with a radio frequency power less than a few kilowatts, and with changing magnetic fields, fill pressures, and gas species.

  9. Particle diffusion in strong field-guided magnetohydrodynamic turbulence

    NASA Astrophysics Data System (ADS)

    Tsang, Yue-Kin; Joanne Mason Collaboration

    2015-11-01

    We consider three-dimensional incompressible magnetohydrodynamic turbulence in the presence of a strong mean background magnetic field. We examine the Lagrangian statistics and characterize the transport properties of the system by numerically tracking a large number of passive massless particles. Previous studies demonstrated that in two dimensions, the presence of a weak background guiding field can suppress turbulent transport in the field-perpendicular direction. The situation in three dimensions is less clear. Here, we measure the single-particle diffusion along different directions with respect to the background magnetic field. By varying the background field strength, we quantify the effect of such guiding field on turbulent diffusion and interpret the results in terms of the Lagrangian velocity function. This work is supported by the UK EPSRC Grant EP/M004546/1.

  10. Mercury's Magnetic Field

    NASA Astrophysics Data System (ADS)

    Johnson, C. L.

    2014-12-01

    Mercury is the only inner solar system body other than Earth to possess an active core dynamo-driven magnetic field and the only planet with a small, highly dynamic magnetosphere. Measurements made by the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft have provided a wealth of data on Mercury's magnetic field environment. Mercury's weak magnetic field was discovered 40 years ago by the Mariner 10 spacecraft, but its large-scale geometry, strength and origin could not be definitively established. MESSENGER data have shown that the field is dynamo-generated and can be described as an offset axisymmetric dipole field (hereafter OAD): the magnetic equator lies ~0.2 RM (RM = 2440 km) north of the geographic equator and the dipole moment is 2.8 x1019 Am2 (~0.03% that of Earth's). The weak internal field and the high, but variable, solar wind ram pressure drive vigorous magnetospheric dynamics and result in an average distance from the planet center to the sub-solar magnetopause of only 1.42 RM. Magnetospheric models developed with MESSENGER data have allowed re-analysis of the Mariner 10 observations, establishing that there has been no measureable secular variation in the internal field over 40 years. Together with spatial power spectra for the OAD, this provides critical constraints for viable dynamo models. Time-varying magnetopause fields induce secondary core fields, the magnitudes of which confirm the core radius estimated from MESSENGER gravity and Earth-based radar data. After accounting for large-scale magnetospheric fields, residual signatures are dominated by additional external fields that are organized in the local time frame and that vary with magnetospheric activity. Birkeland currents have been identified, which likely close in the planetary interior at depths below the base of the crust. Near-periapsis magnetic field measurements at altitudes greater than 200 km have tantalizing hints of crustal fields, but crustal

  11. Observations of Mercury's magnetic field

    NASA Technical Reports Server (NTRS)

    Ness, N. F.; Behannon, K. W.; Lepping, R. P.; Whang, Y. C.

    1975-01-01

    Magnetic field data obtained by Mariner 10 during the third and final encounter with the planet Mercury on 16 March 1975 were studied. A well developed bow shock and modest magnetosphere, previously observed at first encounter on 29 March 1974, were again observed. In addition, a much stronger magnetic field near closest approach, 400 gamma versus 98 gamma, was observed at an altitude of 327 km and approximately 70 deg north Mercurian latitude. Spherical harmonic analysis of the data provide an estimate of the centered planetary magnetic dipole of 4.7 x 10 to the 22nd power Gauss/cu cm with the axis tilted 12 deg to the rotation axis and in the same sense as Earth's. The interplanetary field was sufficiently different between first and third encounters that in addition to the very large field magnitude observed, it argues strongly against a complex induction process generating the observed planetary field. While a possibility exists that Mercury possesses a remanent field due to magnetization early in its formation, a present day active dynamo seems to be a more likely candidate for its origin.

  12. Non-equilibrium magnetic interactions in strongly correlated systems

    SciTech Connect

    Secchi, A.; Brener, S.; Lichtenstein, A.I.; Katsnelson, M.I.

    2013-06-15

    We formulate a low-energy theory for the magnetic interactions between electrons in the multi-band Hubbard model under non-equilibrium conditions determined by an external time-dependent electric field which simulates laser-induced spin dynamics. We derive expressions for dynamical exchange parameters in terms of non-equilibrium electronic Green functions and self-energies, which can be computed, e.g., with the methods of time-dependent dynamical mean-field theory. Moreover, we find that a correct description of the system requires, in addition to exchange, a new kind of magnetic interaction, that we name twist exchange, which formally resembles Dzyaloshinskii–Moriya coupling, but is not due to spin–orbit, and is actually due to an effective three-spin interaction. Our theory allows the evaluation of the related time-dependent parameters as well. -- Highlights: •We develop a theory for magnetism of strongly correlated systems out of equilibrium. •Our theory is suitable for laser-induced ultrafast magnetization dynamics. •We write time-dependent exchange parameters in terms of electronic Green functions. •We find a new magnetic interaction, a “twist exchange”. •We give general expressions for magnetic noise in itinerant-electron systems.

  13. Simulations of Magnetohydrodynamic Turbulence in a Strongly Magnetized Medium

    NASA Astrophysics Data System (ADS)

    Cho, Jungyeon; Lazarian, Alex; Vishniac, Ethan T.

    2002-01-01

    We analyze three-dimensional numerical simulations of driven incompressible magnetohydrodynamic (MHD) turbulence in a periodic box threaded by a moderately strong external magnetic field. We sum over nonlinear interactions within Fourier wave bands and find that the timescale for the energy cascade is consistent with the Goldreich-Sridhar model of strong MHD turbulence. Using higher order longitudinal structure functions, we show that the turbulent motions in the plane perpendicular to the local mean magnetic field are similar to ordinary hydrodynamic turbulence, while motions parallel to the field are consistent with a scaling correction that arises from the eddy anisotropy. We present the structure tensor describing velocity statistics of Alfvénic and pseudo-Alfvénic turbulence. Finally, we confirm that an imbalance of energy moving up and down magnetic field lines leads to a slow decay of turbulent motions, and speculate that this imbalance is common in the interstellar medium, where injection of energy is intermittent both in time and space.

  14. Magnetic dipole in a nonuniform magnetic field

    NASA Astrophysics Data System (ADS)

    Kraftmakher, Yaakov

    2017-05-01

    The magnetic moment of a permanent magnet is determined from forces acting on the magnet in nonuniform magnetic fields produced by two coaxial current-carrying coils. Therefore, the measurements are performed under well controllable and reproducible conditions. With a data-acquisition system, the experiments can be done in a reasonably short time. The magnetic moment of the magnet is in good agreement with values obtained by other experimental techniques. The experiment is well suited for undergraduate laboratories.

  15. High field superconducting magnets

    NASA Technical Reports Server (NTRS)

    Hait, Thomas P. (Inventor); Shirron, Peter J. (Inventor)

    2011-01-01

    A superconducting magnet includes an insulating layer disposed about the surface of a mandrel; a superconducting wire wound in adjacent turns about the mandrel to form the superconducting magnet, wherein the superconducting wire is in thermal communication with the mandrel, and the superconducting magnet has a field-to-current ratio equal to or greater than 1.1 Tesla per Ampere; a thermally conductive potting material configured to fill interstices between the adjacent turns, wherein the thermally conductive potting material and the superconducting wire provide a path for dissipation of heat; and a voltage limiting device disposed across each end of the superconducting wire, wherein the voltage limiting device is configured to prevent a voltage excursion across the superconducting wire during quench of the superconducting magnet.

  16. The interplanetary magnetic field

    NASA Technical Reports Server (NTRS)

    Davis, L., Jr.

    1972-01-01

    Large-scale properties of the interplanetary magnetic field as determined by the solar wind velocity structure are examined. The various ways in which magnetic fields affect phenomena in the solar wind are summarized. The dominant role of high and low velocity solar wind streams that persist, with fluctuations and evolution, for weeks or months is emphasized. It is suggested that for most purposes the sector structure is better identified with the stream structure than with the magnetic polarity and that the polarity does not necessarily change from one velocity sector to the next. Several mechanisms that might produce the stream structure are considered. The interaction of the high and low velocity streams is analyzed in a model that is steady state when viewed in a frame that corotates with the sun.

  17. Thermonuclear fusion in a strong laser field

    NASA Astrophysics Data System (ADS)

    Krainov, V. P.

    2014-08-01

    Thermonuclear fusion induced by the irradiation of solid deuterated cluster targets and foils with fields of strong femtosecond and picosecond laser pulses is discussed. The thermonuclear-fusion process D( d, n)3He in a collision of two deuterons at an energy of 50 to 100 keV in a deuterium cluster target irradiated with a strong laser pulse is discussed. A theory of thermonuclear fusion proceeding upon the irradiation of clusters formed by deuterium iodide (DI) molecules with the field of a superintense femtosecond laser pulse is developed. This theory is based on an above-barrier process in which the sequential multiple inner ionization of atomic ions within a cluster is accompanied by field-induced outer ionization. The yield of neutrons from thermonuclear fusion in a deuteron-deuteron collision after the completion of a laser pulse is calculated. The yield of neutrons is determined for the thermonuclear-fusion reaction proceeding in the interaction of an intense picosecond laser pulse with thin TiD2 foils. A multiple ionization of titanium atoms at the front edge of the laser pulse is considered. The heating of free electron occurs in induced inverse bremsstrahlung in the process of electron scattering on multiply charged titanium ions. The yield of alpha particles in the thermonuclear-fusion reaction involving protons and 11B nuclei that is induced in microdrops by a strong laser field is determined. Experimental data on laser-induced thermonuclear fusion are discussed.

  18. The Sun Magnetic Field

    NASA Image and Video Library

    2011-12-16

    This frame from an animation shows how the magnetic field lines emanating from our sun spiral out into the solar system as the sun rotates. NASA Voyager 1 is in an area scientists are calling the stagnation region, at the outer layer of the heliosphere.

  19. Trapped magnetic field measurements on HTS bulk by peak controlled pulsed field magnetization

    NASA Astrophysics Data System (ADS)

    Ida, Tetsuya; Watasaki, Masahiro; Kimura, Yosuke; Miki, Motohiro; Izumi, Mitsuru

    2010-06-01

    For the past several years, we have studied the high-temperature superconducting (HTS) synchronous motor assembled with melt-textured Gd-Ba-Cu-O bulk magnets. If the single pulse field magnetizes a bulk effectively, size of electrical motor will become small for the strong magnetic field of the HTS magnets without reducing output power of motor. In the previous study, we showed that the HTS bulk was magnetized to excellent cone-shape magnetic field distribution by using the waveform control pulse magnetization (WCPM) method. The WCPM technique made possible the active control of the waveform on which magnetic flux motion depended. We generated the pulse waveform with controlled risetime for HTS bulk magnetization to suppress the magnetic flux motion which decreases magnetization efficiency. The pulsed maximum magnetic flux density with slow risetime is not beyond the maximum magnetic flux density which is trapped by the static field magnetization. But, as for applying the pulse which has fast risetime, the magnetic flux which exceed greatly the threshold penetrates the bulk and causes the disorder of the trapped magnetic distribution. This fact suggests the possibility that the threshold at pulsed magnetization influences the dynamic magnetic flux motion. In this study, Gd-Ba-Cu-O bulk is magnetized by the controlled arbitrary trapezoidal shape pulse, of which the maximum magnetic flux density is controlled not to exceed the threshold. We will present the trapped magnetic characteristics and the technique to generate the controlled pulsed field.

  20. Resonant Strong Field Nonlinear Optical Interactions

    NASA Astrophysics Data System (ADS)

    Coppeta, David Anthony

    This work considers the steady state nonlinear response of a medium subjected to electromagnetic fields which are resonant and/or strong. In this regime, pertubation expansions in the field amplitude(s) diverge and non-pertubative techniques are required. Two general cases are considered. In the first case, radiative renormalization is applied to Four Wave Mixing (FWM) in a four level system with three resonant driving fields. The absorption and generation of a weak FWM signal are considered. Several variants including coherent anti-Stokes Raman scattering are considered. The second case is a two level atom subject to excitation by an arbitrarily amplitude modulated field. The domain of solution is extended to non-equal damping rates with zero detuning from resonance. As an example, the steady state response to step function amplitude modulation is treated.

  1. Deterministic strong-field quantum control

    NASA Astrophysics Data System (ADS)

    Cavaletto, Stefano M.; Harman, Zoltán; Pfeifer, Thomas; Keitel, Christoph H.

    2017-04-01

    Strong-field quantum-state control is investigated, taking advantage of the full—amplitude and phase—characterization of the interaction between matter and intense ultrashort pulses via transient-absorption spectroscopy. As an example, we apply the method to a nondegenerate V -type three-level system modeling atomic Rb, and use a sequence of intense delayed pulses, whose parameters are tailored to steer the system into a desired quantum state. We show how to experimentally enable this optimization by retrieving all quantum features of the light-matter interaction from observable spectra. This provides a full characterization of the action of strong fields on the atomic system, including the dependence upon possibly unknown pulse properties and atomic structures. Precision and robustness of the scheme are tested, in the presence of surrounding atomic levels influencing the system's dynamics.

  2. Magnetic Doppler Imaging of He-strong star HD 184927

    NASA Astrophysics Data System (ADS)

    Yakunin, I.; Wade, G.; Bohlender, D.; Kochukhov, O.; Tsymbal, V.; Tsymbal

    2014-08-01

    We have employed an extensive new timeseries of Stokes I and V spectra obtained with the ESPaDOnS spectropolarimeter at the 3.6-m Canada-France-Hawaii Telescope to investigate the physical parameters, chemical abundance distributions and magnetic field topology of the slowly-rotating He-strong star HD 184927. We infer a rotation period of 9 d .53071 +/- 0.00120 from Hα, Hβ, LSD magnetic measurements and EWs of helium lines. We used an extensive NLTE TLUSTY grid along with the SYNSPEC code to model the observed spectra and find a new value of luminosity. In this poster we present the derived physical parameters of the star and the results of Magnetic Doppler Imaging analysis of the Stokes I and V profiles. Wide wings of helium lines can be described only under the assumption of the presence of a large, very helium-rich spot.

  3. Strongly coupled plasma with electric and magnetic charges

    SciTech Connect

    Liao Jinfeng; Shuryak, Edward

    2007-05-15

    A number of theoretical and lattice results lead us to believe that quark-gluon plasma not too far from T{sub c} contains not only electrically charged quasiparticles - quarks and gluons - but magnetically charged ones--monopoles and dyons--as well. Although binary systems such as charge-monopole and charge-dyon were considered in detail before in both classical and quantum settings, this is the first study of coexisting electric and magnetic particles in a many-body context. We perform a molecular dynamics study of strongly coupled plasmas with {approx}1000 particles and differing fractions of magnetic charge. Correlation functions and Kubo formulas lead to transport properties such as the diffusion constant, the shear viscosity, and electric conductivity: We compare the first two with empirical data from RHIC experiments as well as with results from anti-de-Sitter space/conformal field theory correspondence. We also study a number of collective excitations in these systems.

  4. Field-dressed orbitals in strong-field molecular ionization

    NASA Astrophysics Data System (ADS)

    Siemering, Robert; Njoya, Oumarou; Weinacht, Thomas; de Vivie-Riedle, Regina

    2015-10-01

    We demonstrate the importance of considering the shape of field-dressed molecular orbitals in interpreting angle-dependent measures of strong-field ionization from excited states. Our calculations of angle-dependent ionization for three homologous polyatomic molecules with very similar valence orbitals show that one has to take into account the shape of the field-dressed orbitals rather than the field-free orbitals in order to rationalize the experimental measurements.

  5. Magnetic fields in spiral galaxies

    NASA Astrophysics Data System (ADS)

    Krause, Marita

    2015-03-01

    The magnetic field structure in edge-on galaxies observed so far shows a plane-parallel magnetic field component in the disk of the galaxy and an X-shaped field in its halo. The plane-parallel field is thought to be the projected axisymmetric (ASS) disk field as observed in face-on galaxies. Some galaxies addionionally exhibit strong vertical magnetic fields in the halo right above and below the central region of the disk. The mean-field dynamo theory in the disk cannot explain these observed fields without the action of a wind, which also probably plays an important role to keep the vertical scale heights constant in galaxies of different Hubble types and star formation activities, as has been observed in the radio continuum: At λ6 cm the vertical scale heights of the thin disk and the thick disk/halo in a sample of five edge-on galaxies are similar with a mean value of 300 +/- 50 pc for the thin disk and 1.8 +/- 0.2 kpc for the thick disk (a table and references are given in Krause 2011) with our sample including the brightest halo observed so far, NGC 253, with strong star formation, as well as one of the weakest halos, NGC 4565, with weak star formation. If synchrotron emission is the dominant loss process of the relativistic electrons the outer shape of the radio emission should be dumbbell-like as has been observed in several edge-on galaxies like e.g. NGC 253 (Heesen et al. 2009) and NGC 4565. As the synchrotron lifetime t syn at a single frequency is proportional to the total magnetic field strength B t -1.5, a cosmic ray bulk speed (velocity of a galactic wind) can be defined as v CR = h CR /t syn = 2 h z /t syn , where h CR and h z are the scale heights of the cosmic rays and the observed radio emission at this freqnency. Similar observed radio scale heights imply a self regulation mechanism between the galactic wind velocity, the total magnetic field strength and the star formation rate SFR in the disk: v CR ~ B t 1.5 ~ SFR ~ 0.5 (Niklas & Beck 1997).

  6. Anomaly-Induced Dynamical Refringence in Strong-Field QED

    NASA Astrophysics Data System (ADS)

    Mueller, N.; Hebenstreit, F.; Berges, J.

    2016-08-01

    We investigate the impact of the Adler-Bell-Jackiw anomaly on the nonequilibrium evolution of strong-field quantum electrodynamics (QED) using real-time lattice gauge theory techniques. For field strengths exceeding the Schwinger limit for pair production, we encounter a highly absorptive medium with anomaly induced dynamical refractive properties. In contrast to earlier expectations based on equilibrium properties, where net anomalous effects vanish because of the trivial vacuum structure, we find that out-of-equilibrium conditions can have dramatic consequences for the presence of quantum currents with distinctive macroscopic signatures. We observe an intriguing tracking behavior, where the system spends longest times near collinear field configurations with maximum anomalous current. Apart from the potential relevance of our findings for future laser experiments, similar phenomena related to the chiral magnetic effect are expected to play an important role for strong QED fields during initial stages of heavy-ion collision experiments.

  7. Anomaly-Induced Dynamical Refringence in Strong-Field QED.

    PubMed

    Mueller, N; Hebenstreit, F; Berges, J

    2016-08-05

    We investigate the impact of the Adler-Bell-Jackiw anomaly on the nonequilibrium evolution of strong-field quantum electrodynamics (QED) using real-time lattice gauge theory techniques. For field strengths exceeding the Schwinger limit for pair production, we encounter a highly absorptive medium with anomaly induced dynamical refractive properties. In contrast to earlier expectations based on equilibrium properties, where net anomalous effects vanish because of the trivial vacuum structure, we find that out-of-equilibrium conditions can have dramatic consequences for the presence of quantum currents with distinctive macroscopic signatures. We observe an intriguing tracking behavior, where the system spends longest times near collinear field configurations with maximum anomalous current. Apart from the potential relevance of our findings for future laser experiments, similar phenomena related to the chiral magnetic effect are expected to play an important role for strong QED fields during initial stages of heavy-ion collision experiments.

  8. Magnetic fields and cancer

    SciTech Connect

    Jones, T.L.

    1993-10-01

    This letter is a response to an article by Savitz and Kaune, EHP 101:76-80. W-L wire code was applied to data from a 1988 Denver study, and an association was reported between high W-L wire code and childhood cancer. This author discusses several studies and provides explanations which weakens the argument that classification error resulted in an appreciable reduction in the association between W-L high wire code and childhood cancer. In conclusion, the fact that new wire code is only weakly correlated with magnetic field measurements (in the same manner as the original W-L wire code) suggests that the newly reported stronger association with childhood cancer is likely due to factors other than magnetic fields. Differential residential mobility and differential residential age are two possible explanations and are suggestive that the reported association may be false.

  9. Photonic Magnetic Field Sensor

    DTIC Science & Technology

    2007-11-02

    reduce feedback in fiber optic links can be the basis for excellent magnetic field sensors. Based on the giant magneto-optical ( GMO ) or Faraday...Squids are those based upon the giant magneto-optical ( GMO ) effect in ferrimagnetic materials or YIG garnets and the giant magneto-resistance (GMR...effect in manganese based compounds. The development of the GMO material was mostly motivated by the need for compact, in-line fiber optical

  10. Magnetic field reconnection

    NASA Astrophysics Data System (ADS)

    Axford, W. I.

    The fundamental principles of particle acceleration by magnetic reconnection in cosmic plasmas are reviewed. The history of reconnection models is traced, and consideration is given to the Kelvin-Helmholtz theorem, the frozen-field theorem, the application of the Kelvin-Helmholtz theorem to a collisionless plasma, solutions to specific reconnection problems, and configurational instability. Diagrams and graphs are provided, and the objections raised by critics of the reconnection theory and/or its astrophysical applications are discussed.

  11. Magnetic field evolution in tidal disruption events

    NASA Astrophysics Data System (ADS)

    Bonnerot, Clément; Price, Daniel J.; Lodato, Giuseppe; Rossi, Elena M.

    2017-08-01

    When a star gets tidally disrupted by a supermassive black hole, its magnetic field is expected to pervade its debris. In this paper, we study this process via smoothed particle magnetohydrodynamical simulations of the disruption and early debris evolution including the stellar magnetic field. As the gas stretches into a stream, we show that the magnetic field evolution is strongly dependent on its orientation with respect to the stretching direction. In particular, an alignment of the field lines with the direction of stretching induces an increase of the magnetic energy. For disruptions happening well within the tidal radius, the star compression causes the magnetic field strength to sharply increase by an order of magnitude at the time of pericentre passage. If the disruption is partial, we find evidence for a dynamo process occurring inside the surviving core due to the formation of vortices. This causes an amplification of the magnetic field strength by a factor of ˜10. However, this value represents a lower limit since it increases with numerical resolution. For an initial field strength of 1 G, the magnetic field never becomes dynamically important. Instead, the disruption of a star with a strong 1 MG magnetic field produces a debris stream within which magnetic pressure becomes similar to gas pressure a few tens of hours after disruption. If the remnant of one or multiple partial disruptions is eventually fully disrupted, its magnetic field could be large enough to magnetically power the relativistic jet detected from Swift J1644+57. Magnetized streams could also be significantly thickened by magnetic pressure when it overcomes the confining effect of self-gravity.

  12. Coronal Magnetic Field Models

    NASA Astrophysics Data System (ADS)

    Wiegelmann, Thomas; Petrie, Gordon J. D.; Riley, Pete

    2017-09-01

    Coronal magnetic field models use photospheric field measurements as boundary condition to model the solar corona. We review in this paper the most common model assumptions, starting from MHD-models, magnetohydrostatics, force-free and finally potential field models. Each model in this list is somewhat less complex than the previous one and makes more restrictive assumptions by neglecting physical effects. The magnetohydrostatic approach neglects time-dependent phenomena and plasma flows, the force-free approach neglects additionally the gradient of the plasma pressure and the gravity force. This leads to the assumption of a vanishing Lorentz force and electric currents are parallel (or anti-parallel) to the magnetic field lines. Finally, the potential field approach neglects also these currents. We outline the main assumptions, benefits and limitations of these models both from a theoretical (how realistic are the models?) and a practical viewpoint (which computer resources to we need?). Finally we address the important problem of noisy and inconsistent photospheric boundary conditions and the possibility of using chromospheric and coronal observations to improve the models.

  13. Nanomagnets with high shape anisotropy and strong crystalline anisotropy: perspectives on magnetic force microscopy.

    PubMed

    Campanella, H; Jaafar, M; Llobet, J; Esteve, J; Vázquez, M; Asenjo, A; del Real, R P; Plaza, J A

    2011-12-16

    We report on a new approach for magnetic imaging, highly sensitive even in the presence of external, strong magnetic fields. Based on FIB-assisted fabricated high-aspect-ratio rare-earth nanomagnets, we produce groundbreaking magnetic force tips with hard magnetic character where we combine a high aspect ratio (shape anisotropy) together with strong crystalline anisotropy (rare-earth-based alloys). Rare-earth hard nanomagnets are then FIB-integrated to silicon microcantilevers as highly sharpened tips for high-field magnetic imaging applications. Force resolution and domain reversing and recovery capabilities are at least one order of magnitude better than for conventional magnetic tips. This work opens new, pioneering research fields on the surface magnetization process of nanostructures based either on relatively hard magnetic materials-used in magnetic storage media-or on materials like superparamagnetic particles, ferro/antiferromagnetic structures or paramagnetic materials.

  14. Multi-electron systems in strong magnetic fields II: A fixed-phase diffusion quantum Monte Carlo application based on trial functions from a Hartree-Fock-Roothaan method

    NASA Astrophysics Data System (ADS)

    Boblest, S.; Meyer, D.; Wunner, G.

    2014-11-01

    We present a quantum Monte Carlo application for the computation of energy eigenvalues for atoms and ions in strong magnetic fields. The required guiding wave functions are obtained with the Hartree-Fock-Roothaan code described in the accompanying publication (Schimeczek and Wunner, 2014). Our method yields highly accurate results for the binding energies of symmetry subspace ground states and at the same time provides a means for quantifying the quality of the results obtained with the above-mentioned Hartree-Fock-Roothaan method.

  15. Oxide superconductors under magnetic field

    NASA Technical Reports Server (NTRS)

    Kitazawa, K.

    1990-01-01

    One of the current most serious problems for the oxide superconductors from the standpoint of practical application is the various novel features derived mainly from their extremely short coherence. In particular, the coherence length so far observed in the cuprate superconductors is in the range of 0.1 nm perpendicular to the CuO2 plane. This seems to be creating most of the difficulties in the device fabrication and in the performance under the magnetic field. Some of the superconducting properties under the magnetic field will be discussed in terms of the short coherence length. A model will be presented based on the gradual strengthening of the pinning force with decrease in temperature and the weak coupling at the grain boundaries. Secondly, the broadening of the superconducting transition under the magnetic field is discussed. This is observed significantly only when the field is applied perpendicular to the basal plane and the relative orientation of the current to the field is insignificant in determining the extent of the broadening. Besides, the change in the strength of the pinning force does not affect the width of the broadening. From these observations discussions will be made on a model based on the giant fluctuation. Based on this model, it is predicted that the coherence length along the c-axis will be the single most important material parameter to determine the performance of the superconductor under a strong magnetic field. It seems that BYCO is superior in this regard to Bi- or Tl-systems as far as the performance at 77 K is considered, although another material with the coherence length slightly longer along the c-axis is still highly desired.

  16. Oxide superconductors under magnetic field

    NASA Technical Reports Server (NTRS)

    Kitazawa, K.

    1991-01-01

    One of the current most serious problems for the oxide superconductors from the standpoint of practical application is the various novel features derived mainly from their extremely short coherence. In particular, the coherence length so far observed in the cuprate superconductors is in the range of 0.1 nm perpendicular to the CuO2 plane. This seems to be creating most of the difficulties in the device fabrication and in the performance under the magnetic field. Some of the superconducting properties under the magnetic field will be discussed in terms of the short coherence length. A model will be presented based on the gradual strengthening of the pinning force with decrease in temperature and the weak coupling at the grain boundaries. Secondly, the broadening of the superconducting transition under the magnetic field is discussed. This is observed significantly only when the field is applied perpendicular to the basal plane and the relative orientation of the current to the field is insignificant in determining the extent of broadening. Besides, the change in the strength of the pinning force does not affect the width of the broadening. From these observations discussions will be made on a model based on the giant fluctuation. Based on this model, it is predicted that the coherence length along the c-axis will be the single most important material parameter to determine the performance of the superconductor under a strong magnetic field. It seems that BYCO is superior in this regard to Bi- or Tl-systems as far as the performance at 77 K is considered, although another material with the coherence length slightly longer along the c-axis is still highly desired.

  17. Central Magnetic Field of a Magnetic White Dwarf Star

    NASA Astrophysics Data System (ADS)

    Shah, Hridaya; Sebastian, Kunnat

    2017-07-01

    Observations of over-luminous Type 1a supernovae have prompted researchers to come up with various hypotheses in order to explain them. One hypothesis is based on the explosion of a progenitor super-massive magnetic white dwarf star. These stars are assumed to have very strong magnetic fields inside of them. However, there is a lack of analytic proof of the existence of such magnetic fields in the magnetic white dwarf stars. In this work, we plan to address an analytic proof of the existence of very strong magnetic fields in the center of these magnetic white dwarfs. We will see that for a one Landau-level white dwarf star, with central density {10}9{--}{10}11 {{g}} {{cm}}-3, it is possible to have central magnetic fields of the order of {10}13{--}{10}15G at least. In the presence of strong magnetic fields, the threshold densities chosen for this work that correspond to instabilities due to general relativity and pycnonuclear reactions have been found to increase so that the matter does not acquire instability at such central densities.

  18. Quantum dynamics in strong fluctuating fields

    NASA Astrophysics Data System (ADS)

    Goychuk, Igor; Hänggi, Peter

    A large number of multifaceted quantum transport processes in molecular systems and physical nanosystems, such as e.g. nonadiabatic electron transfer in proteins, can be treated in terms of quantum relaxation processes which couple to one or several fluctuating environments. A thermal equilibrium environment can conveniently be modelled by a thermal bath of harmonic oscillators. An archetype situation provides a two-state dissipative quantum dynamics, commonly known under the label of a spin-boson dynamics. An interesting and nontrivial physical situation emerges, however, when the quantum dynamics evolves far away from thermal equilibrium. This occurs, for example, when a charge transferring medium possesses nonequilibrium degrees of freedom, or when a strong time-dependent control field is applied externally. Accordingly, certain parameters of underlying quantum subsystem acquire stochastic character. This may occur, for example, for the tunnelling coupling between the donor and acceptor states of the transferring electron, or for the corresponding energy difference between electronic states which assume via the coupling to the fluctuating environment an explicit stochastic or deterministic time-dependence. Here, we review the general theoretical framework which is based on the method of projector operators, yielding the quantum master equations for systems that are exposed to strong external fields. This allows one to investigate on a common basis, the influence of nonequilibrium fluctuations and periodic electrical fields on those already mentioned dynamics and related quantum transport processes. Most importantly, such strong fluctuating fields induce a whole variety of nonlinear and nonequilibrium phenomena. A characteristic feature of such dynamics is the absence of thermal (quantum) detailed balance.ContentsPAGE1. Introduction5262. Quantum dynamics in stochastic fields531 2.1. Stochastic Liouville equation531 2.2. Non-Markovian vs. Markovian discrete

  19. Magnetic Field Topology in Jets

    NASA Technical Reports Server (NTRS)

    Gardiner, T. A.; Frank, A.

    2000-01-01

    We present results on the magnetic field topology in a pulsed radiative. jet. For initially helical magnetic fields and periodic velocity variations, we find that the magnetic field alternates along the, length of the jet from toroidally dominated in the knots to possibly poloidally dominated in the intervening regions.

  20. Low field magnetic resonance imaging

    DOEpatents

    Pines, Alexander; Sakellariou, Dimitrios; Meriles, Carlos A.; Trabesinger, Andreas H.

    2010-07-13

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