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Field B (field + b)

Distribution by Scientific Domains

Physics and Astronomy	80%

Selected Abstracts

The hydrogen atom, revisited: Parallel-field magnetic resonance,

CONCEPTS IN MAGNETIC RESONANCE, Issue 5 2006
John A. Weil
Abstract Consideration of the magnetic resonance spectroscopy of the free hydrogen atom (1H0) reveals that, in addition to the well-known transitions (EPR and NMR) occurring between the four spin states when the excitation magnetic field B1 is perpendicular to the static external field B, there exists a combination line (simultaneous electronic and nuclear spin flips) when B1 , B, which becomes strong under some circumstances. The latter phenomenon is focused on and discussed herein, in some detail. © 2006 Wiley Periodicals, Inc. Concepts Magn Reson Part A 28A: 331,336, 2006 [source]

Presheath in Fully Ionized Collisional Plasma in a Magnetic Field

CONTRIBUTIONS TO PLASMA PHYSICS, Issue 7 2005
B. Alterkop
Abstract The quasineutral presheath layer at the boundary of fully ionized, collisional, and magnetized plasma with an ambipolar flow to an adjacent absorbing wall was analyzed using a two fluid magneto-hydrodynamic model. The plasma is magnetized by a uniform magnetic field B, imposed parallel to the wall. The analysis did not assume that the dependence of the particle density on the electric potential in the presheath is according to the Boltzmann equilibrium, and the dependence of the mean collision time , on the varying plasma density within the presheath was not neglected. Based on the model equations, algebraic expressions were derived for the dependence of the plasma density, electron and ion velocities, and the electrostatic potential on the position within the presheath. The solutions of the model equations depended on two parameters: Hall parameter (, ), and the ratio (, ), where , = ZTe /(ZTe + Ti ), and Te , Ti and Z are the electron and ion temperatures and ionicity, respectively. The characteristic scale of the presheath extension is several times ri /, , where ri is the ion radius at the ion sound velocity. The electric potential could have a non monotonic distribution in the presheath. The ions are accelerated to the Bohm velocity (sound velocity) in the presheath mainly near the presheath-sheath boundary, in a layer of thickness ,ri /, . The electric field accelerates the ions in the whole presheath if their velocity in the wall direction exceeds their thermal velocity. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

The influence of Pb-ion irradiation on melt-textured YBa2Cu3Ox crystals

CRYSTAL RESEARCH AND TECHNOLOGY, Issue 2 2009
I. M. Obaidat
Abstract Melt-textured YBa2Cu3Ox crystals have been irradiated along the c -axis with 208Pb56+ ions corresponding to dose matching fields, B, = 0.5 T and B, = 2.0 T. Magnetization measurements were conducted along the ab plane of the samples. The strength of pinning sites was investigated by measuring magnetization hysterisis and the saturation remanent magnetization MR at several temperatures. We have found that the pinning strength was considerably enhanced after irradiation at both doses. Interestingly, the pinning strength at a Pb-ion irradiation which corresponds to the dose matching field B, = 0.5 T, was found to be significantly larger than that at the dose matching field B, = 2.0 T at all temperatures. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

The , -ray burst phenomenon treated as the collapse of a QED magnetized vacuum bubble: analogy with sonoluminescence

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 4 2000
YU. N. Gnedin
We treat the phenomenon of a , -ray burst as the non-linear collapse of a magnetic cavity surrounding a neutron star with extremely large magnetic field B,1015,1016 G due to the process of bubble shape instability in the resonant MHD field of an accreting plasma or on a neutron star surface. The QED effect of vacuum polarizability by a strong magnetic field is taken into a consideration. We develop an analogy with the phenomenon of sonoluminescence in which the gas bubble is located in a surrounding liquid with a driven sound intensity. [source]

The absence of an ideal two dimensionality in QHE

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 5 2003
M. Saglam
Abstract The solution of the Schrödinger equation for the Quantum Hall Effect (QHE) system is given for a harmonic impurity potential. It is shown that at a magnetic field B = Bi if there are ,i Landau levels below or just equal to the Fermi level then there will be at least 2,i sublayers of electrons. At the extreme limit, when all the electrons are in the ground state Landau level, there will be at least two sublayers playing a role in the system. [source]