scholarly journals A battery-powered floating current source of 100 A for precise and fast control of magnetic field

AIP Advances ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 125207
Author(s):  
Yu-Meng Yang ◽  
Bo Xiao ◽  
Wen-Chao Ji ◽  
Xuan-Kai Wang ◽  
Han-Ning Dai ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Current Source ◽  
Floating Current Source ◽  
Fast Control

Fluid flow in a hemispherical container induced by a distributed source of current and a superimposed uniform magnetic field

1980 ◽  
Vol 99 (1) ◽  
pp. 1-11 ◽  
Author(s):  
R. E. Craine ◽  
N. P. Weatherill
Keyword(s):  
Magnetic Field ◽  
Fluid Flow ◽  
Uniform Magnetic Field ◽  
Current Source ◽  
Welding Process ◽  
Nonlinear Flow ◽  
Axial Section ◽  
Axis Of Symmetry ◽  
Source Sink ◽  
Applied Fields

In arc welding electromagnetic forces are thought to be the major cause of motion in the weldpool, and it has recently been found by experimentalists that the application to the workpiece of a uniform magnetic field normal to the weldpool surface appears to stabilize the welding process. In this paper we investigate motion in a hemisphere due to a stationary distributed current source with a superimposed uniform magnetic field applied parallel to the axis of symmetry. When inertial effects are ignored and a simple source-sink model of the current source is introduced, we obtain an analytic solution for the fluid flow valid for low currents and low applied fields. A numerical scheme is then developed to solve the full nonlinear-flow problem and results are obtained for the source-sink model of the current source and for a more realistic numerically constructed distributed current source. For values of the externally applied magnetic field and the current flowing through the hemisphere typical of those occurring in practical welding situations we discover that the flow in an axial section through the pool is radially outwards on the free surface. This is in the opposite direction to that generally predicted by the theory when there is no superimposed magnetic field.

scholarly journals Magnetometric resistivity tomography using chaos polynomial expansion

2020 ◽  
Vol 221 (3) ◽  
pp. 1469-1483
Author(s):  
M T Vu ◽  
A Jardani ◽  
A Revil ◽  
M Jessop
Keyword(s):  
Magnetic Field ◽  
Electrical Conductivity ◽  
Current Source ◽  
Electrical Potential ◽  
Ground Surface ◽  
Theoretical Background ◽  
Polynomial Expansion ◽  
Model Parameters ◽  
Inversion Algorithm ◽  
Heterogeneous Distribution

SUMMARY We present an inversion algorithm to reconstruct the spatial distribution of the electrical conductivity from the analysis of magnetometric resistivity (MMR) data acquired at the ground surface. We first review the theoretical background of MMR connecting the generation of a magnetic field in response to the injection of a low-frequency current source and sink in the ground given a known distribution of electrical conductivity in the subsurface of the Earth. The forward modelling is based on sequentially solving the Poisson equation for the electrical potential distribution and the magnetostatic (Biot and Savart) equation for the magnetic field. Then, we introduce a Gauss–Newton inversion algorithm in which the logarithm of the electrical conductivity field is parametrized by using the chaos polynomial expansion in order to reduce the number of model parameters. To illustrate how the method works, the algorithm is successfully applied on four synthetic models with 3-D heterogeneous distribution of the electrical conductivity. Finally, we apply our algorithm to a field case study in which seepage was known to be occurring along an embankment of a headrace channel to a power station.

On the emission of radiation from a localized current source in a magnetoplasma

1978 ◽  
Vol 19 (2) ◽  
pp. 201-225 ◽  
Author(s):  
M. J. Giles
Keyword(s):  
Magnetic Field ◽  
Refractive Index ◽  
External Magnetic Field ◽  
Current Source ◽  
Dielectric Tensor ◽  
External Current ◽  
New Approach ◽  
Dispersion Surface ◽  
Radiation Zone ◽  
Angle Of Rotation

A new approach to the problem of the radiation emitted from a localized external current source embedded in a magnetoplasma is described. It is argued that the calculation of the fields in the radiation zone can be substantially simplified by adopting at the outset a suitable parametrization of the dispersion surface. We illustrate the approach by calculating the far fields using the full expression for the dielectric tensor of a warm magnetized electron gas. In this case one can take the angle of rotation about the external magnetic field and the square of the refractive index as the curvilinear co-ordinates of the dispersion surface. The form of the surfaces of constant phase and the amplitudes of the emitted waves are described for each topologically different region of parameter space and their structures are related to the shapes of the refractive index surfaces. Attention is also drawn to the existence of locally cylindrical waves that can produce beams which are highly collimated in the direction of the external magnetic field.

Prediction of magnetic field emissions by current source reconstruction using radial basis function network

2015 ◽  
Vol 51 (16) ◽  
pp. 1243-1245 ◽  
Author(s):  
Yinliang Diao ◽  
Weinong Sun ◽  
Sai Wing Leung ◽  
Kwok Hung Chan ◽  
Yun Ming Siu
Keyword(s):  
Magnetic Field ◽  
Radial Basis Function ◽  
Basis Function ◽  
Radial Basis Function Network ◽  
Current Source ◽  
Source Reconstruction ◽  
Field Emissions ◽  
Radial Basis ◽  
Function Network

Current Source Design for 3D Magnetic Field Simulation

2013 ◽  
Vol 760-762 ◽  
pp. 1354-1359
Author(s):  
Zhi Li ◽  
Shu Bao Pan
Keyword(s):  
Magnetic Field ◽  
Design Principle ◽  
Current Source ◽  
Three Dimensional ◽  
Calibration Method ◽  
Constant Current ◽  
Constant Current Source ◽  
Precision Error ◽  
Magnetic Field Simulation ◽  
A Current

This paper designs a current source which is used for simulating the three dimensional magnetic field. Gives the circuit schematic, Analyzes the design principle of the circuit and puts forward the calibration method of software which is suitable for the operation in microprocessor and improves the output accuracy of the constant current source. Actual test shows that the output of the constant current source is 0.1mA-500mA and the precision error is less than 0.03% of full scale. It has been used in the degaussing device testing and maintenance. The performance is stable and reliable achieves good results.

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