Pseudo-three-dimensional convective cell motion in a magnetized plasma

1984 ◽  
Vol 31 (2) ◽  
pp. 231-238 ◽  
Author(s):  
P. K. Shukla ◽  
M. Y. Yu
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Mode Coupling ◽  
Three Dimensional ◽  
Convective Cell ◽  
Magnetized Plasma ◽  
Space Plasmas ◽  
Linear And Nonlinear ◽  
Convective Cells ◽  
Cell Motion

Linear and nonlinear mechanisms for generating convective cells with finite but small parallel (to the external magnetic field B0) wavelength are presented. The problems of mode-coupling as well as quasi-steady nonlinear mode structures are analytically studied. Possible applications in space plasmas are discussed.

scholarly journals Room temperature giant magnetostriction in single-crystal nickel nanowires

2019 ◽  
Vol 11 (1) ◽  
Author(s):  
Anastasios Pateras ◽  
Ross Harder ◽  
Sohini Manna ◽  
Boris Kiefer ◽  
Richard L. Sandberg ◽  
...  
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Single Crystal ◽  
Room Temperature ◽  
Magnetic Energy ◽  
Mechanical Energy ◽  
Three Dimensional ◽  
Local Strain ◽  
Nickel Nanowires ◽  
Giant Magnetostriction

Abstract Magnetostriction is the emergence of a mechanical deformation induced by an external magnetic field. The conversion of magnetic energy into mechanical energy via magnetostriction at the nanoscale is the basis of many electromechanical systems such as sensors, transducers, actuators, and energy harvesters. However, cryogenic temperatures and large magnetic fields are often required to drive the magnetostriction in such systems, rendering this approach energetically inefficient and impractical for room-temperature device applications. Here, we report the experimental observation of giant magnetostriction in single-crystal nickel nanowires at room temperature. We determined the average values of the magnetostrictive constants of a Ni nanowire from the shifts of the measured diffraction patterns using the 002 and 111 Bragg reflections. At an applied magnetic field of 600 Oe, the magnetostrictive constants have values of λ100 = −0.161% and λ111 = −0.067%, two orders of magnitude larger than those in bulk nickel. Using Bragg coherent diffraction imaging (BCDI), we obtained the three-dimensional strain distribution inside the Ni nanowire, revealing nucleation of local strain fields at two different values of the external magnetic field. Our analysis indicates that the enhancement of the magnetostriction coefficients is mainly due to the increases in the shape, surface-induced, and stress-induced anisotropies, which facilitate magnetization along the nanowire axis and increase the total magnetoelastic energy of the system.

An improved scheme for the calculation of NMR chemical shifts in periodic systems based on gauge including atomic orbitals and density functional theory

2011 ◽  
Vol 89 (9) ◽  
pp. 1150-1161 ◽  
Author(s):  
Dmitry Skachkov ◽  
Mykhaylo Krykunov ◽  
Tom Ziegler
Keyword(s):  
Magnetic Field ◽  
Density Functional Theory ◽  
External Magnetic Field ◽  
Density Functional ◽  
Three Dimensional ◽  
Nuclear Magnetic Moment ◽  
Zero Order ◽  
Periodic Systems ◽  
Functional Theory ◽  
Atomic Orbitals

We report here on an improved first principles method that can determine NMR shielding tensors for periodic systems. Our scheme evaluates the shielding tensor as the second derivative of the total electronic energy with respect to a nuclear magnetic moment and an external magnetic field. Both the induced current density J(α) due to the first perturbation from the nuclear magnetic moment as well as the interaction of J(α) with the second perturbation in the form of an external magnetic field are evaluated analytically. Our approach is based on Kohn–Sham density functional theory and gauge-including atomic orbitals. It employs a Bloch basis set made up of Slater-type or numeric atomic orbitals and represents the Kohn–Sham potential fully without the use of effective core potentials. The method is implemented into the periodic program BAND. The new scheme represents an improvement over a previously proposed method in that use can be made of the zero-order Kohn–Sham orbitals from a calculation based on a primitive cell instead of a supercell. Further, J(α) is evaluated analytically rather than by a finite difference approach. The improvements reduce the required computational time by up to two orders of magnitude for three-dimensional systems. Such a reduction is made possible by the fact that we are using atomic centered basis functions. The new implementation is further able to take into account scalar relativistic effects within the zero-order regular approximation. Results from calculations of NMR shielding constants based on the present approach are presented for systems with one-, two-, and three-dimensional periodicity. The reported values are compared to experiment and results from the previously proposed scheme.

Convective cell and Alfvén vortices in an inhomogeneous rotating cold magnetoplasma

1987 ◽  
Vol 37 (2) ◽  
pp. 199-208 ◽  
Author(s):  
P. K. Shukla ◽  
R. Bharuthram
Keyword(s):  
Nonlinear Equations ◽  
Particle Transport ◽  
Special Class ◽  
Convective Cell ◽  
Stationary Solutions ◽  
Magnetized Plasma ◽  
Alfvén Waves ◽  
Convective Cells ◽  
Shear Alfven Waves ◽  
Analytical Expressions

It is shown that double vortices are a special class of stationary solutions of the set of nonlinear equations that governs the dynamics of modified convective cells and shear Alfvén waves in a cold rotating magnetized plasma. Criteria for the existence of dipole vortices as well as several analytical expressions for the vortex profiles are presented. It is suggested that modified convective cell and Alfvén dipole vortices may cause anomalous cross-field particle transport in a low-β plasma, such as the ionosphere.

Tunable properties of one-dimensional photonic crystals that incorporate a defect layer of a magnetized plasma

2017 ◽  
Vol 31 (31) ◽  
pp. 1750239 ◽  
Author(s):  
Arafa H. Aly ◽  
Hussein A. Elsayed ◽  
Ayman A. Ameen ◽  
S. H. Mohamed
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Plasma Layer ◽  
Photonic Band Gap ◽  
Defect Layer ◽  
Magnetized Plasma ◽  
Characteristic Matrix ◽  
Angle Of Incidence ◽  
One Dimensional ◽  
Photonic Band

In this paper, we theoretically investigate the transmittance characteristics of one-dimensional defective photonic crystal in microwave radiations based on the fundamentals of the characteristic matrix method. Here, the defect layer is magnetized plasma. The numerical results show the appearance of defect peaks inside the Photonic Band Gap. The external magnetic field has a significant effect on the permittivity of the defect layer. Therefore, the position and intensity of the defect peak are strongly affected by the external magnetic field. Moreover, we have investigated the different parameters on the defect peaks as the plasma density, the thickness of the plasma layer and the angle of incidence. Wherefore, the proposed structure could be the cornerstone for many applications in microwave regions such as narrowband filters.

scholarly journals Energy and momentum losses in the process of neutrino scattering on plasma electrons in the presence of a magnetic field

Open Physics ◽  
2003 ◽  
Vol 1 (1) ◽  
Author(s):  
Nickolay Mikheev ◽  
Elena Narynskaya
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Electron Scattering ◽  
Volume Density ◽  
Neutrino Energy ◽  
Magnetized Plasma ◽  
Neutrino Scattering ◽  
Energy And Momentum

AbstractThe neutrino-electron scattering in a dense degenerate magnetized plasma under the conditions μ 2 > 2eB ≫ μE is investigated. The volume density of the neutrino energy and momentum losses due to this process are calculated. The results we have obtained demonstrate that plasma in the presence of an external magnetic field is more transparent for neutrino than for non-magnetized plasma. It is shown that neutrino scattering under conditions considered does not lead to the neutrino force acting on plasma.

scholarly journals Влияние магнитного поля на термодинамические и магнитные свойства антиферромагнитной модели Изинга на объемно-центрированной кубической решетке

2020 ◽  
Vol 62 (2) ◽  
pp. 229
Author(s):  
А.К. Муртазаев ◽  
М.К. Рамазанов ◽  
К.Ш. Муртазаев ◽  
М.А. Магомедов ◽  
М.К. Бадиев
Keyword(s):  
Magnetic Field ◽  
Phase Transition ◽  
External Magnetic Field ◽  
Three Dimensional ◽  
Nearest Neighbors ◽  
Body Centered Cubic ◽  
Cubic Lattice ◽  
The Monte Carlo Method ◽  
Body Centered Cubic Lattice ◽  
Second Order Phase Transition

The influence of the external magnetic field on the phase transitions, thermodynamic and magnetic properties of the three-dimensional Ising model of antiferromagnetic on a body-centered cubic lattice taking into account the interactions of the second nearest neighbors is studied by the replica algorithm of the Monte Carlo method. A phase diagram of the dependence of the critical temperature on the external magnetic field has been constructed. It is shown that a second-order phase transition is observed in the considered range of magnetic field values

scholarly journals A Method of the Riemann–Hilbert Problem for Zhang’s Conjecture 2 in a Ferromagnetic 3D Ising Model: Topological Phases

Mathematics ◽  
2021 ◽  
Vol 9 (22) ◽  
pp. 2936
Author(s):  
Zhidong Zhang ◽  
Osamu Suzuki
Keyword(s):  
Magnetic Field ◽  
Ising Model ◽  
External Magnetic Field ◽  
Hilbert Problem ◽  
Three Dimensional ◽  
Preceding Paper ◽  
Mathematical Structure ◽  
Topological Phases ◽  
Riemann Hilbert Problem ◽  
3D Ising Model

A method of the Riemann–Hilbert problem is employed for Zhang’s conjecture 2 proposed in Philo. Mag. 87 (2007) 5309 for a ferromagnetic three-dimensional (3D) Ising model in a zero external magnetic field. In this work, we first prove that the 3D Ising model in the zero external magnetic field can be mapped to either a (3 + 1)-dimensional ((3 + 1)D) Ising spin lattice or a trivialized topological structure in the (3 + 1)D or four-dimensional (4D) space (Theorem 1). Following the procedures of realizing the representation of knots on the Riemann surface and formulating the Riemann–Hilbert problem in our preceding paper [O. Suzuki and Z.D. Zhang, Mathematics 9 (2021) 776], we introduce vertex operators of knot types and a flat vector bundle for the ferromagnetic 3D Ising model (Theorems 2 and 3). By applying the monoidal transforms to trivialize the knots/links in a 4D Riemann manifold and obtain new trivial knots, we proceed to renormalize the ferromagnetic 3D Ising model in the zero external magnetic field by use of the derivation of Gauss–Bonnet–Chern formula (Theorem 4). The ferromagnetic 3D Ising model with nontrivial topological structures can be realized as a trivial model on a nontrivial topological manifold. The topological phases generalized on wavevectors are determined by the Gauss–Bonnet–Chern formula, in consideration of the mathematical structure of the 3D Ising model. Hence we prove the Zhang’s conjecture 2 (main theorem). Finally, we utilize the ferromagnetic 3D Ising model as a platform for describing a sensible interplay between the physical properties of many-body interacting systems, algebra, topology, and geometry.

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