Superconductors With Structured Surfaces: Fields and Currents

1987 ◽  
Vol 101 ◽  
Author(s):  
Z.C. Wu ◽  
Daniel A. Jelski ◽  
Thomas F. George
Keyword(s):  
Magnetic Field ◽  
The Other ◽  
Ginzburg Landau ◽  
Landau Model ◽  
Structured Surfaces ◽  
Field Parallel ◽  
First Case ◽  
The Magnetic Field ◽  
Effect Of Structure ◽  
Effect Of Surface

ABSTRACTThis paper discusses the behavior of currents and fields along a structured superconductor. First the effect of surface structure on supercurrents is investigated. Then the effect of structure on the critical nucleation field is discussed in two cases, one with the magnetic field parallel to the ripples and the other with the field parallel to the grating wavenumber. In the first case, it is found that the critical field is reduced as a function of grating height, whereas in the latter case it is increased. Finally, the relevance of this work for laser-induced chemistry above a superconducting surface is discussed. The Ginzburg-Landau model is used throughout.

ON THE CONTINUITY OF THE RESPONSE MAP AND AN ALTERNATIVE SHOOTING METHOD FOR THE HALF-SPACE GINZBURG–LANDAU MODEL

2006 ◽  
Vol 16 (09) ◽  
pp. 1527-1558
Author(s):  
CATHERINE BOLLEY ◽  
BERNARD HELFFER
Keyword(s):  
Magnetic Field ◽  
Half Space ◽  
Shooting Method ◽  
The Other ◽  
Complete Analysis ◽  
Qualitative Properties ◽  
Ginzburg Landau ◽  
Landau Model ◽  
Ginzburg Landau Equations ◽  
Physical Literature

As a consequence of a rather complete analysis of the qualitative properties of the solutions of the Ginzburg–Landau equations, we prove, in this paper, both the continuity of a fundamental map σ, called response map in the physical literature on superconductors, and the convergence of an efficient algorithm for the computation of the graph of σ. The response map σ gives the intensity h of the external magnetic field for which the Ginzburg–Landau equations (in a half-space) have a solution such that the parameter order has a prescribed value at the boundary of the sample. Our study involves a shooting method on either one or the other unknown of the system; our algorithm has been introduced in Bolley–Helffer for small values of the Ginzburg–Landau parameter κ and extended in Bolley to any value of κ. Our preceding mathematical studies were not sufficient to prove the convergence, but a recent result (in Ref. 3) on the monotonicity of the solutions with respect to h, combined with a more extensive use of the properties of the solutions of the Ginzburg–Landau system, allow us to complete the proof and to get, as a by-product, the continuity of σ.

scholarly journals The effect of simplifications of a numerical mesh on the results of electromagnetic analysis of the Nuclotron-type cable

2018 ◽  
Vol 177 ◽  
pp. 08004
Author(s):  
Łukasz Tomków
Keyword(s):  
Magnetic Field ◽  
Electric Current ◽  
Current Density ◽  
Electric Current Density ◽  
Electromagnetic Analysis ◽  
First Case ◽  
Single Region ◽  
The Magnetic Field

The model of a single Nuclotron-type cable is presented. The goal of this model is to assess the behaviour of the cable under different loads. Two meshes with different simplifications are applied. In the first case, the superconductor in the cable is modelled as single region. Second mesh considers individual strands of the cable. The significant differences between the distributions of the electric current density obtained with both models are observed. The magnetic field remains roughly similar.

scholarly journals THE ENERGY EIGENVALUES OF THE TWO DIMENSIONAL HYDROGEN ATOM IN A MAGNETIC FIELD

2006 ◽  
Vol 15 (06) ◽  
pp. 1263-1271 ◽  
Author(s):  
A. SOYLU ◽  
O. BAYRAK ◽  
I. BOZTOSUN
Keyword(s):  
Magnetic Field ◽  
Hydrogen Atom ◽  
Iteration Method ◽  
Weak Magnetic Field ◽  
The Other ◽  
Asymptotic Iteration Method ◽  
Iterative Approach ◽  
Two Dimensional ◽  
Energy Eigenvalues ◽  
The Magnetic Field

In this paper, the energy eigenvalues of the two dimensional hydrogen atom are presented for the arbitrary Larmor frequencies by using the asymptotic iteration method. We first show the energy eigenvalues for the case with no magnetic field analytically, and then we obtain the energy eigenvalues for the strong and weak magnetic field cases within an iterative approach for n=2-10 and m=0-1 states for several different arbitrary Larmor frequencies. The effect of the magnetic field on the energy eigenvalues is determined precisely. The results are in excellent agreement with the findings of the other methods and our method works for the cases where the others fail.

scholarly journals The influence of resistivity gradients on shock conditions for a Petschek reconnection geometry

2016 ◽  
Vol 34 (4) ◽  
pp. 421-425
Author(s):  
Christian Nabert ◽  
Karl-Heinz Glassmeier
Keyword(s):  
Magnetic Field ◽  
Necessary Conditions ◽  
The Other ◽  
Diffusion Region ◽  
Two Dimensional ◽  
Characteristic Velocity ◽  
Magnetohydrodynamic Equations ◽  
One Dimensional ◽  
The Magnetic Field ◽  
Alfven Velocity

Abstract. Shock waves can strongly influence magnetic reconnection as seen by the slow shocks attached to the diffusion region in Petschek reconnection. We derive necessary conditions for such shocks in a nonuniform resistive magnetohydrodynamic plasma and discuss them with respect to the slow shocks in Petschek reconnection. Expressions for the spatial variation of the velocity and the magnetic field are derived by rearranging terms of the resistive magnetohydrodynamic equations without solving them. These expressions contain removable singularities if the flow velocity of the plasma equals a certain characteristic velocity depending on the other flow quantities. Such a singularity can be related to the strong spatial variations across a shock. In contrast to the analysis of Rankine–Hugoniot relations, the investigation of these singularities allows us to take the finite resistivity into account. Starting from considering perpendicular shocks in a simplified one-dimensional geometry to introduce the approach, shock conditions for a more general two-dimensional situation are derived. Then the latter relations are limited to an incompressible plasma to consider the subcritical slow shocks of Petschek reconnection. A gradient of the resistivity significantly modifies the characteristic velocity of wave propagation. The corresponding relations show that a gradient of the resistivity can lower the characteristic Alfvén velocity to an effective Alfvén velocity. This can strongly impact the conditions for shocks in a Petschek reconnection geometry.

scholarly journals Влияние параллельного слоям магнитного поля на фототок в GaAs/AlAs p-i-n-структурах

2022 ◽  
Vol 56 (1) ◽  
pp. 107
Author(s):  
И.А. Ларкин ◽  
Ю.Н. Ханин ◽  
Е.Е. Вдовин
Keyword(s):  
Magnetic Field ◽  
Wavelength Range ◽  
Strong Dependence ◽  
Diffusion Current ◽  
Radiation Wavelength ◽  
Quantization Level ◽  
Dimensional Quantization ◽  
Field Parallel ◽  
The Magnetic Field

The behavior of the photocurrent in GaAs / AlAs p-i-n heterostructures is studied in a magnetic field parallel to the heterolayers in the wavelength range from 395 to 650 nm. A strong dependence of the non-oscillating component of the photocurrent on the radiation wavelength associated with the suppression of the diffusion current by the magnetic field was found. It is shown that the behavior of the oscillating component of the photocurrent in a magnetic field does not depend on the wavelength of light and is determined by the transfer of electrons through the dimensional quantization level in a triangular near-barrier well. It is shown that the suppression of the oscillating component by the magnetic field is due to the smearing of the level in the triangular well due to the motion of electrons parallel to the walls of the well and perpendicular to the magnetic field.

scholarly journals Dynamical Galactic Halos

1993 ◽  
Vol 157 ◽  
pp. 415-419
Author(s):  
D. Breitschwerdt ◽  
H.J. Völk ◽  
V. Ptuskin ◽  
V. Zirakashvili
Keyword(s):  
Magnetic Field ◽  
Cosmic Rays ◽  
The Other ◽  
Galactic Rotation ◽  
Galactic Halos ◽  
Magnetic Forces ◽  
Dynamical Coupling ◽  
Field Lines ◽  
The Magnetic Field ◽  
Open Magnetic Field

It is argued that the description of the magnetic field in halos of galaxies should take into account its dynamical coupling to the other major components of the interstellar medium, namely thermal plasma and cosmic rays (CR's). It is then inevitable to have some loss of gas and CR's (galactic wind) provided that there exist some “open” magnetic field lines, facilitating their escape, and a sufficient level of self-generated waves which couple the particles to the gas. We discuss qualitatively the topology of the magnetic field in the halo and show how galactic rotation and magnetic forces can be included in such an outflow picture.

On the minimizers of the Ginzburg–Landau energy for high kappa: the one-dimensional case

1997 ◽  
Vol 8 (4) ◽  
pp. 331-345 ◽  
Author(s):  
AMANDINE AFTALION
Keyword(s):  
Magnetic Field ◽  
Asymptotic Behaviour ◽  
Dimensional Case ◽  
Numerical Computations ◽  
Ginzburg Landau ◽  
Landau Model ◽  
One Dimensional ◽  
Landau Parameter ◽  
Convergence Results ◽  
The One

The Ginzburg–Landau model for superconductivity is examined in the one-dimensional case. First, putting the Ginzburg–Landau parameter κ formally equal to infinity, the existence of a minimizer of this reduced Ginzburg–Landau energy is proved. Then asymptotic behaviour for large κ of minimizers of the full Ginzburg–Landau energy is analysed and different convergence results are obtained, according to the exterior magnetic field. Numerical computations illustrate the various behaviours.

The Effect of Surface Layers in Epitaxial N-Type Hg1−xCdxTe

1989 ◽  
Vol 161 ◽  
Author(s):  
K.K. Parat ◽  
N.R. Taskar ◽  
I.B. Bhat ◽  
S.K. Ghandhi
Keyword(s):  
Magnetic Field ◽  
Field Dependence ◽  
Vapor Phase ◽  
Hall Coefficient ◽  
Diagnostic Technique ◽  
Organometallic Vapor Phase Epitaxy ◽  
Surface Layers ◽  
Surface Electrons ◽  
The Magnetic Field ◽  
Effect Of Surface

ABSTRACTThe presence of low mobility surface electrons on n-Hg1−1CdxTe is generally not apparent in the temperature dependence of the Hall Coefficient (RH) or the Hall mobility (µH) of the layer. However, its influence is clearly seen in the magnetic field (B-field) dependence of RH. The B-field dependence of RH can be analyzed to extract the bulk and surface carrier concentrations and their respective mobilities.This diagnostic technique has been used for evaluating epitaxial Hg1−xCdxTe layers grown by organometallic vapor phase epitaxy (OMVPE), which have been converted to n-type by annealing in Hg overpressure. In addition, the effect of anodic sulfide passivation on the B-field dependence of Hall coefficient is also outlined.

scholarly journals Effect of Background Magnetic Field on Type-II Superconductor under Oscillating Magnetic Field Simulated Using Ginzburg-Landau Model

2018 ◽  
Vol 2018 ◽  
pp. 1-7
Author(s):  
Hasnain Mehdi Jafri ◽  
Congpeng Zhao ◽  
Houbing Huang ◽  
Xingqiao Ma
Keyword(s):  
Magnetic Field ◽  
Carrier Concentration ◽  
Static Magnetic Field ◽  
Thermal Quenching ◽  
Phase Changes ◽  
Ginzburg Landau ◽  
Landau Model ◽  
Background Magnetic Field ◽  
Oscillating Magnetic Field ◽  
Energy Components

Cubic superconducting sample was simulated using time-dependent Ginzburg-Landau model under oscillating magnetic field with and without additional background static magnetic field. Vortex dynamics including entrance and exit from the sample was simulated. Magnetization and carrier concentration densities of the sample were studied as a function of external magnetic field variations. Anomalies in carrier concentration density were observed at certain values of the magnetic field which were correlated with the entrance and exit processes of vortices. Area swept by superconductor magnetization with magnetic field was observed to have a hysteresis-like behavior where area representing energy dissipated per cycle. This energy accumulation was suggested to cause instability in superconductor over the number of cycles and may result in thermal quenching. Temporal distribution of energy components showed consistency with the pattern observed for carrier concentration and magnetization under oscillating magnetic field. Rapid phase changes with magnetic oscillations resulted in oscillations in energy components, and irregular peaks and ripples in superconducting energy represent the situation of exit and entry of vortices. While the rise in interaction energy with cycles is referred to vortex relaxation time in a cycle, this energy is expected to accumulate and take other forms (e.g., heat) and is predicted to cause thermal quenching. In the presence of background static magnetic field, this energy dissipation was calculated to increase significantly while superconductor is subjected to oscillating magnetic field.

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