Band structure for relativistic charge carriers submitted to a helical magnetic field

2021 ◽  
pp. 2150141
Author(s):  
D. Martínez ◽  
J. A. Reyes ◽  
G. Reyes ◽  
C. G. Avendaño
Keyword(s):  
Magnetic Field ◽  
Band Structure ◽  
Charge Carriers ◽  
Momentum Operator ◽  
Rotating Magnetic Field ◽  
Band Gaps ◽  
Spatial Period ◽  
System Parameters ◽  
Helical Magnetic Field ◽  
The Magnetic Field

In this paper, we consider a clockwise rotating magnetic field around the [Formula: see text]-axis and charge carriers which impinge normally to the [Formula: see text] plane. We obtained analytically the spectrum of the momentum operator [Formula: see text] and found the existence of a band structure from which the movement of these charge carries is filtered according to the spatial period of the magnetic field or its intensity. Also we exhibit the existence of three band gaps (one total or primary and two partials) whose width depends on the system parameters.

Swirling Flow of Magnetic Fluid in Multi-Pole Rotating Magnetic Field

2003 ◽  
Author(s):  
Kenichi Kamioka ◽  
Ryuichiro Yamane
Keyword(s):  
Magnetic Field ◽  
Fluid Flow ◽  
Circular Cylinder ◽  
Phase Velocity ◽  
Magnetic Fluid ◽  
Swirling Flow ◽  
Peak Velocity ◽  
Rotating Magnetic Field ◽  
Outer Periphery ◽  
The Magnetic Field

The experiments are conducted on the magnetic fluid flow induced by the multi-pole rotating magnetic field in a circular cylinder. The numbers of poles are two, four, six, eight and twelve. The applied electric current and frequency are 2∼6 A and 20∼60 Hz, respectively. The peak velocity of the flow increases with the increase in the strength and the phase velocity of the magnetic field. As the increase in the number of poles, the flow shifts to the outer periphery.

scholarly journals Investigation of mixing time in liquid under influence of rotating magnetic field

2017 ◽  
Vol 38 (4) ◽  
pp. 555-565
Author(s):  
Alicja Przybył ◽  
Rafał Rakoczy ◽  
Maciej Konopacki ◽  
Marian Kordas ◽  
Radosław Drozd ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Experimental Investigation ◽  
Reynolds Number ◽  
Mixing Time ◽  
Rotating Magnetic Field ◽  
Homogenization Time ◽  
Set Up ◽  
The Relationship ◽  
The Magnetic Field

Abstract The aim of the study was to present an experimental investigation of the influence of the RMF on mixing time. The obtained results suggest that the homogenization time for the tested experimental set-up depending on the frequency of the RMF can be worked out by means of the relationship between the dimensionless mixing time number and the Reynolds number. It was shown that the magnetic field can be applied successfully to mixing liquids.

Spin reorientation transition: phase diagrams and entropy change

2011 ◽  
Vol 1310 ◽  
Author(s):  
Vittorio Basso ◽  
Carlo P. Sasso ◽  
Michaela Kuepferling
Keyword(s):  
Magnetic Field ◽  
Easy Axis ◽  
Entropy Change ◽  
Rotating Magnetic Field ◽  
Spin Reorientation ◽  
Temperature Dependent ◽  
First Order ◽  
Crystalline Anisotropy ◽  
The Magnetic Field ◽  
Magneto Crystalline Anisotropy

ABSTRACTIn this paper we review the phase diagram and derive the entropy change for spin reorientation transitions by considering first order magnetization process theory with temperature dependent magneto-crystalline anisotropy constants. We derive the magnetic field-induced entropy change Δs for a transition between easy axis and easy plane, showing that for alternating magnetic field, Δs has a change of sign at the reorientation temperature, while for rotating magnetic field its sign is definite. We apply the model to CoZn W-type barium ferrite.

Waves in a cold plasma with spatially periodic sheared fields

1989 ◽  
Vol 42 (1) ◽  
pp. 153-164 ◽  
Author(s):  
D. A. Diver ◽  
E. W. Laing ◽  
C. C. Sellar
Keyword(s):  
Magnetic Field ◽  
Wave Propagation ◽  
Cold Plasma ◽  
Density Fluctuations ◽  
Rotating Magnetic Field ◽  
Physical Parameters ◽  
Order Ordinary Differential Equation ◽  
Spatially Periodic ◽  
Constant Magnitude ◽  
The Magnetic Field

We have studied wave propagation in a cold plasma, in the presence of a spatially rotating magnetic field of constant magnitude. New features introduced by this variation include streaming velocities and a plasma current in equilibrium and density fluctuations. We present only the case of wave propagation along the axis of rotation of the magnetic field. A set of ordinary differential equations for the electric field components is obtained, which may be combined into a single fourth-order ordinary differential equation with periodic coefficients. Solutions are obtained in closed form and their nature is determined in terms of the physical parameters of the System, magnetic field strength, number density and wave frequency.

scholarly journals Reading M87's DNA: A Double Helix Revealing a Large-scale Helical Magnetic Field

2021 ◽  
Vol 923 (1) ◽  
pp. L5
Author(s):  
Alice Pasetto ◽  
Carlos Carrasco-González ◽  
José L. Gómez ◽  
José-Maria Martí ◽  
Manel Perucho ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Large Scale ◽  
Double Helix ◽  
High Sensitivity ◽  
Polarization Degree ◽  
Very Large Array ◽  
Wide Range ◽  
Helical Magnetic Field ◽  
Helical Configuration ◽  
The Magnetic Field

Abstract We present unprecedented high-fidelity radio images of the M87 jet. We analyzed Jansky Very Large Array broadband full-polarization radio data from 4 to 18 GHz. The observations were taken with the most extended configuration (A configuration), which allows the study of the emission of the jet up to kiloparsec scales with a linear resolution of ∼10 pc. The high sensitivity and resolution of our data allow us to resolve the jet width. We confirm a double-helix morphology of the jet material between ∼300 pc and ∼1 kpc. We found a gradient of the polarization degree with a minimum at the projected axis and maxima at the jet edges and a gradient in the Faraday depth with opposite signs at the jet edges. We also found that the behavior of the polarization properties along the wide range of frequencies is consistent with internal Faraday depolarization. All of these characteristics strongly support the presence of a helical magnetic field in the M87 jet up to 1 kpc from the central black hole, although the jet is most likely particle-dominated at these large scales. Therefore, we propose a plausible scenario in which the helical configuration of the magnetic field has been maintained to large scales thanks to the presence of Kelvin–Helmholtz instabilities.

SHOT NOISE OF ELECTRON PAIRS IN NONCYCLIC AND NON-ADIABATIC MAGNETIC FIELD

2007 ◽  
Vol 21 (17) ◽  
pp. 3065-3074
Author(s):  
XIAN-JUN YE
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Shot Noise ◽  
Beam Splitter ◽  
Rotating Magnetic Field ◽  
Triplet States ◽  
Electron Pairs ◽  
Singlet And Triplet States ◽  
The Magnetic Field ◽  
Symmetric Properties

By adding a rotating magnetic field in one incoming lead, we calculate the shot noise with different incident states in a 4-lead beam-splitter. The result shows that the shot noise of singlet and triplet states oscillates with the external magnetic field and depends on the symmetric properties of the incident states. Thus, the singlet, entangled triplet, and polarized states can be distinguished by adjusting the magnetic field.

Study of an aluminium mixing system based on permanent magnets

2020 ◽  
Vol 39 (1) ◽  
pp. 192-197
Author(s):  
Andrey Morev ◽  
Alexander Aliferov
Keyword(s):  
Magnetic Field ◽  
Permanent Magnets ◽  
Rotation Velocity ◽  
Rotating Magnetic Field ◽  
The Finite Element Method ◽  
Ansys Software ◽  
Angular Rotation ◽  
Content Type ◽  
Maximum Value ◽  
The Magnetic Field

Purpose The purpose of this paper is to investigate the effect of the rotating magnetic field of permanent magnets on the aluminium melt bath. Design/methodology/approach This model was developed in the ANSYS software package and is based on the application of the finite element method and finite volume. Findings The distribution of the velocity of the melt in a cylindrical vertical bath and the dependence of the maximum value of the melt displacement on the angular rotation velocity of the system of permanent magnets is obtained. Originality/value This work focusses on the interaction of the magnetic field of the moving magnets with the molten metal.

MAGNETORESISTANCE AND FIELD DEPENDENCE OF THE HALL EFFECT IN INDIUM ANTIMONIDE

1958 ◽  
Vol 36 (5) ◽  
pp. 527-538 ◽  
Author(s):  
Gaston Fischer ◽  
D. K. C. MacDonald
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Hall Effect ◽  
Field Dependence ◽  
Indium Antimonide ◽  
Charge Carriers ◽  
Band Theory ◽  
Hall Effect Measurements ◽  
A Charge ◽  
The Magnetic Field

Magnetoresistance and Hall-effect measurements in InSb are described. This semiconductor has charge carriers with sufficiently long mean free paths, l, that it is possible, even at room temperature and with available magnetic fields, to obtain l/r values considerably greater than unity, r being the orbital radius of a charge carrier moving in the applied magnetic field. The classical two-band theory has been found to account rather well for the results up to the highest magnetic fields employed. A review of the underlying assumptions of this theory is presented, and simple formulae are derived which allow the concentrations and mobilities of both types of carriers to be calculated from the magnetic field dependence of the resistivity, ρH, and of the Hall-constant, AH. The parameter Λ ≡ [(AH−A0)/A0]/[(ρH−ρ0)/ρ0] provides a useful means to check the consistency of the theory and can give some indication of the variation of the mobilities with the magnetic field.

scholarly journals A comparative analysis of the parameters of a rotating magnetic field inductor when using concentric and loop windings

2021 ◽  
pp. 12-18
Author(s):  
V. I. Milykh ◽  
M. G. Tymin
Keyword(s):  
Magnetic Field ◽  
Single Layer ◽  
Rotating Magnetic Field ◽  
Geometrical Parameters ◽  
Stator Winding ◽  
Electromagnetic Parameters ◽  
Working Chamber ◽  
Three Phase ◽  
Technological Processing ◽  
The Magnetic Field

Introduction. Three-phase inductors of a rotating magnetic field are used in grinders, separators and stirrers for the technological processing of bulk and liquid substances. This occurs in a cylindrical working chamber under the influence of ferromagnetic elements in the form of pieces of iron wire, which move together with the field. Problem. By analogy with three-phase induction motors, for the stator of inductors a concentric winding is adopted, which is a diametric single-layer winding. When moving from such motors to an inductor, its operating conditions have changed due to the significantly increased non-magnetic space inside the inductor compared to the motor clearances. The difference in the frontal parts of the phase windings has become essential for the electromagnetic parameters and the structure of the magnetic field in the inductor working chamber. Therefore, a loop shortened stator winding, which is symmetrical, can be considered as an alternative to a concentric diametric winding. Goal. The aim of the work is to compare the dimensional and electromagnetic parameters of a rotating magnetic field inductor in two versions of its three-phase winding: concentric single-layer diametrical and loop shortened two-layer. Methodology. Comparison of the windings is carried out through a detailed analysis of the geometrical parameters of their frontal parts, as well as through numerical-field calculations of the electromagnetic parameters of the inductor as a whole and the distribution of the magnetic field in its working chamber. Results. A significant difference in the geometrical parameters of the frontal parts of the two windings under inductor conditions was revealed. The loop version of the winding makes it possible to reduce the length of the winding conductor, its active resistance, as well as the reactance of its frontal dissipation. At the same time the asymmetry of the phase windings is excluded and an increase in the homogeneity of the magnetic field in the inductor working chamber is provided. Originality. The scientific novelty of the work lies in the development of a method of comparative analysis of the windings under the conditions of the rotating magnetic field inductor and in revealing the advantages of a loop shortened winding compared to the used concentric diametric winding. Practical value. The loop shortened stator winding recommended for the inductor will eliminate the asymmetry of its electromagnetic system. Thereby, the quality of its work in the technological processing of different substances is significantly increased due to ensuring the homogeneity of the magnetic field in the working chamber. At the same time, the copper conductor of the winding is still saved, and the efficiency of the inductor is also increased by reducing the power of electrical losses.

scholarly journals Hilltop Inflation and Generation of Helical Magnetic Field

Universe ◽  
2022 ◽  
Vol 8 (1) ◽  
pp. 26
Author(s):  
Sumanta Chakraborty ◽  
Supratik Pal ◽  
Soumitra SenGupta
Keyword(s):  
Magnetic Field ◽  
Power Spectrum ◽  
Quantum Electrodynamics ◽  
Anomaly Cancellation ◽  
Significant Strength ◽  
Intergalactic Magnetic Field ◽  
Helical Magnetic Field ◽  
Sufficient Strength ◽  
Large Parameter Space ◽  
The Magnetic Field

Primordial magnetic field generated in the inflationary era can act as a viable source for the present day intergalactic magnetic field of sufficient strength. We present a fundamental origin for such a primordial generation of the magnetic field, namely through anomaly cancellation of U(1) gauge field in quantum electrodynamics in the context of hilltop inflation. We have analysed at length the power spectrum of the magnetic field, thus generated, which turns out to be helical in nature. We have also found that magnetic power spectrum has significant scale-dependence giving rise to a non-trivial magnetic spectral index, a key feature of this model. Interestingly, there exists a large parameter space, where magnetic field of significant strength can be produced.

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