Effect of Spatial Distribution of Electronic and Ionic Currents on the Magnetic Field Induced by Galvanic Corrosion

2002 ◽  
Vol 149 (3) ◽  
pp. B65 ◽  
Author(s):  
Hitoshi Yashiro ◽  
Masahito Yoshizawa ◽  
Naoaki Kumagai ◽  
Johann H. Hinken
Keyword(s):  
Magnetic Field ◽  
Spatial Distribution ◽  
Galvanic Corrosion ◽  
Ionic Currents ◽  
The Magnetic Field

Kinematic dynamo problem in a linear velocity field

1984 ◽  
Vol 144 ◽  
pp. 1-11 ◽  
Author(s):  
Ya. B. Zel'Dovich ◽  
A. A. Ruzmaikin ◽  
S. A. Molchanov ◽  
D. D. Sokoloff
Keyword(s):  
Magnetic Field ◽  
Spatial Distribution ◽  
Velocity Field ◽  
Random Matrix ◽  
Magnetic Energy ◽  
Linear Velocity ◽  
Finite Conductivity ◽  
Kinematic Dynamo ◽  
Linear Velocity Field ◽  
The Magnetic Field

A magnetic field is shown to be asymptotically (t → ∞) decaying in a flow of finite conductivity with v = Cr, where C = Cζ(t) is a random matrix. The decay is exponential, and its rate does not depend on the conductivity. However, the magnetic energy increases exponentially owing to growth of the domain occupied by the field. The spatial distribution of the magnetic field is a set of thin ropes and (or) layers.

scholarly journals Magnetic Field Instability of a Plasma in a Beam of Electromagnetic Radiation

1980 ◽  
Vol 35 (4) ◽  
pp. 461-463 ◽  
Author(s):  
O. M. Gradov ◽  
L. Stenflo
Keyword(s):  
Magnetic Field ◽  
Spatial Distribution ◽  
Magnetic Fields ◽  
Field Strength ◽  
Electromagnetic Radiation ◽  
Characteristic Time ◽  
Incident Radiation ◽  
Maximum Value ◽  
Quasi Stationary State ◽  
The Magnetic Field

Abstract A beam of electromagnetic radiation can generate magnetic fields in plasmas. It is shown that those fields grow significantly when the incident radiation is sufficiently strong. We obtain expressions for the characteristic time of the growth of the fields as well as for their spatial distribution and point out a possible mechanism, which can lead to the formation of a quasi-stationary state. The maximum value of the magnetic field strength is estimated

scholarly journals Optical and Radio Surface Photometry of NGC 891

1990 ◽  
Vol 140 ◽  
pp. 223-224
Author(s):  
R.J. Allen ◽  
S. Sukumar ◽  
F.X. Hu ◽  
P. C. Van Der Kruit
Keyword(s):  
Magnetic Field ◽  
Spatial Distribution ◽  
Surface Brightness ◽  
Relativistic Electrons ◽  
Synchrotron Emission ◽  
Surface Photometry ◽  
Star Forming ◽  
Evolved Stars ◽  
Optical Continuum ◽  
The Magnetic Field

A general correlation between the radio and optical continuum surface brightness has been found in the edge-on galaxy NGC 891. This suggests that the relativistic electrons are produced/accelerated in the vicinity of evolved stars or stellar remnants which have a spatial distribution similar to old disk stars. In this picture, the magnetic field required for the synchrotron emission is carried up from the disk to high Z through instabilities and star-forming activity in the plane.

scholarly journals Asymptotic Methods in the Nonlinear Mean-field Dynamo

1991 ◽  
Vol 130 ◽  
pp. 135-139
Author(s):  
D.D. Sokoloff ◽  
A. Shukurov ◽  
A.A. Ruzmaikin
Keyword(s):  
Magnetic Field ◽  
Spatial Distribution ◽  
Steady State ◽  
Main Part ◽  
Asymptotic Methods ◽  
Mean Field ◽  
Coriolis Forces ◽  
The Mean ◽  
The Magnetic Field ◽  
Mean Field Dynamo

AbstractWe discuss the methods and results of analysis of nonlinear mean-field dynamo models based on α-quenching in two asymptotic regimes, namely for weakly and highly supercritical excitation. In the former case the spatial distribution of the steady-state magnetic field is close to that given by the neutrally stable eigenfunction of the corresponding kinematic dynamo. In the latter case the magnetic field distribution within the main part of the dynamo volume is presumably determined by the balance between the Lorentz and Coriolis forces while near the boundaries boundary layers arise in which the field adjusts itself to the boundary conditions. The asymptotic behaviour of the highly supercritical αω-dynamos is sensitive to the particular form of dependence of the mean helicity on magnetic field while α2-dynamos are less sensitive to this dependence.

scholarly journals Calculation of field of spectrometric magnet with 0.13 m gap

2019 ◽  
Vol 204 ◽  
pp. 11001
Author(s):  
Ivan Yudin
Keyword(s):  
Magnetic Field ◽  
Spatial Distribution ◽  
Field Distribution ◽  
Integral Method ◽  
Modes Of Operation ◽  
Physical Data ◽  
Spectrometer Magnet ◽  
The Magnetic Field ◽  
Three Components

The spectrometric magnet is widely used in experiments on highenergy physics and a number of other fields. In this report, we present the results of calculating the magnetic field for a variant of a magnet with an interpolar gap of 0.13 m. Our spectrometer magnet has external dimensions of 2.95 x 2.12 x 1.62 m and an aperture (occupied by the beam) of 0.30 x 0.13 m. The simulation was carried out using an integral method of magnetostatics. The results of the calculated field distribution of the analyzing magnet with interpolar 0.13 m gap are given. The calculation was performed for the volume 0.33 x 0.0645 x 1.5 m, the volume of overlapping dimensions. The calculation of the spatial distribution of the three components of the magnetic field of the magnet described in the work is performed to obtain the information about the magnitude and uniformity of the magnetic field for different modes of operation of the spectrometer. The obtained results are planned for using in the processing of physical data.

scholarly journals Fluctuation Effects of Magnetohydrodynamic Micro-Vortices on Odd Chirality in Magnetoelectrolysis

2020 ◽  
Vol 6 (3) ◽  
pp. 43
Author(s):  
Iwao Mogi ◽  
Ryoichi Aogaki ◽  
Kohki Takahashi
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Field Dependence ◽  
Magnetic Field Dependence ◽  
Ionic Currents ◽  
Copper Films ◽  
Field Polarity ◽  
Vortex Model ◽  
Self Organized ◽  
The Magnetic Field

The magnetic field dependence of chiral surface formation was investigated in magnetoelectrodeposition (MED) and magnetoelectrochemical etching (MEE) of copper films. The MED and MEE was conducted in magnetic fields of up to 5 T, which were parallel or antiparallel to the ionic currents. The MED films prepared in high magnetic fields of 5 and 3 T exhibited odd chirality for magnetic field polarity, as expected on the basis of the magnetohydrodynamic (MHD) vortex model. However, the films prepared in the lower fields of 2.5 and 2 T exhibited breaking of odd chirality. Similar magnetic field dependence was observed in the surface chirality of MEE films. These results imply that the fluctuation in the self-organized state of micro-MHD vortices is responsible for the breaking of odd chirality.

scholarly journals Измерение пространственных распределений температуры электронов в облаках полистироловых пеллетов, испаряющихся в плазме гелиотрона LHD

2018 ◽  
Vol 44 (9) ◽  
pp. 41
Author(s):  
И.А. Шаров ◽  
В.Ю. Сергеев ◽  
И.В. Мирошников ◽  
Б.В. Кутеев ◽  
N. Tamura ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Spatial Distribution ◽  
Local Thermodynamic Equilibrium ◽  
Longitudinal Distribution ◽  
Emission Coefficient ◽  
Pellet Surface ◽  
Local Emission ◽  
Temperature Of Electrons ◽  
First Time ◽  
The Magnetic Field

AbstractTwo methods for measuring the spatial distribution of the temperature of electrons in a cloud near a polystyrene pellet that ablates in LHD heliotron plasma are described. The first method is based on measuring the ratio of the local emission-coefficient values at wavelengths of 486 ± 5 nm (the H _β line) and 630 ± 5 nm (continuum). The second (new) method is based on the measurement of radiation distributions of the H _β line in the direction along the magnetic field. Both the methods use an assumption about the partial local thermodynamic equilibrium in the cloud and show close results. It is shown for the first time that the temperature of cloud electrons increases from 0.8 eV in the immediate vicinity of the pellet surface to 6.0–7.0 eV at a distance of 6–8 mm from the pellet in the direction along the magnetic field, which agrees with the experimentally observed longitudinal distribution of the H _β radiation in the cloud.

scholarly journals Magnetic-field measurement and simulation of a field-free line magnetic-particle scanner

2017 ◽  
Vol 3 (2) ◽  
Author(s):  
Jan Stelzner ◽  
Thorsten M. Buzug
Keyword(s):  
Magnetic Field ◽  
Spatial Distribution ◽  
Magnetic Particle ◽  
Imaging Modality ◽  
Magnetic Field Measurement ◽  
Magnetic Particle Imaging ◽  
Particle Imaging ◽  
Harmful Radiation ◽  
The Magnetic Field ◽  
Magnetization Behavior

AbstractIn 2005, B. Gleich and J. Weizenecker initially presented the tracer based medical imaging modality Magnetic Particle Imaging (MPI). It uses the nonlinear magnetization behavior of super paramagnetic iron oxide nanoparticles (SPIONs). MPI has the potential to perform real-time imaging in the sub millimeter-range without the use of harmful radiation. To acquire a particle signal from the tracer, an alternating homogenous magnetic field (drive field) is applied. Due to the nonlinearity of the particle magnetization, the magnetic field is distorted and higher harmonics are generated that indicate a particle concentration within the field of view (FOV). For the spatial distribution, another magnetic field that exhibits a high gradient (selection field) is applied simultaneously. Basically, there are two different types of selection fields containing either a field- free point (FFP) or a field-free line (FFL). Because of magnetic saturation, only SPIONs within the close vicinity of the FFP or FFL contribute to the particle signal. As the FFP is moved by the drive field through the FOV a spatial distribution of the SPIONs can be obtained. In the other encoding concept, the FFL rotates and is additionally translated by the drive field to obtain one dimensional projections for various angles. In this work, the currently world’s largest FFL MPI Scanner is investigated. Single components of the generated magnetic field are measured precisely to accomplish an accurate simulation of a translating and rotating FFL.

scholarly journals Breaking of Odd Chirality in Magnetoelectrodeposition of Copper Films on Micro-Electrodes

2021 ◽  
Vol 7 (11) ◽  
pp. 142
Author(s):  
Iwao Mogi ◽  
Ryoichi Aogaki ◽  
Kohki Takahashi
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Chiral Symmetry ◽  
Ionic Currents ◽  
Copper Films ◽  
Electrode Diameter ◽  
Field Polarity ◽  
Vortex Model ◽  
Disc Electrodes ◽  
The Magnetic Field

The surface chirality was investigated in magnetoelectrodeposition (MED) of copper films on micro-disc electrodes with the diameters of 100 and 25 µm. The MED was conducted in the magnetic fields of 1–5 T, which were parallel or antiparallel to the ionic currents. In the case of 100 µm-electrodes, the MED films prepared in 2 and 3 T exhibited odd chirality for the magnetic field polarity, as expected in the magnetohydrodynamic (MHD) vortex model. However, the films prepared in the higher fields of 4 and 5 T exhibited breaking of odd chirality. In the case of the 25 µm-electrode, the broken odd chirality was observed in 2 and 3 T. These results indicate that the strong vertical MHD flows induce the breaking of odd chirality. The mapping of chiral symmetry on the axes of the magnetic field and electrode diameter demonstrate that the odd chirality could be easily broken by the fluctuation of micro-MHD vortices.

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