Design of highly uniform three-dimensional square magnetic field coils for external magnetic shielding of magnetometers

The induced magnetic field for three-dimensional bio-convective flow of Casson nanofluid containing gyrotactic microorganisms along a vertical stretching sheet is investigated. The movement of these microorganisms cause bioconvection and they act as bio-active mixers that help in stabilising the nanoparticles in the suspension. The two forces, Thermophoresis and Brownian motion are incorporated in the Mathematical model along with Stefan blowing. The resulting model is transformed to ordinary differential equations using similarity transformations and are solved using [Formula: see text] method. The Velocity, Induced Magnetic field, Temperature, Concentration of Nanoparticles, and Motile density profiles are interpreted graphically. It is observed that the Casson parameter decreases the flow velocity and enhances the temperature, concentration, and motile density profiles and also it is noticed that the blowing enhances the nanofluid profiles whereas, suction diminishes the nanofluid profiles. On the other hand, it is perceived that the rate of heat conduction is enhanced with Thermophoresis and Brownian motion.

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The on-axis magnetic well and Mercier's criterion for arbitrary stellarator geometries

Journal of Plasma Physics ◽

10.1017/s0022377821000465 ◽

2021 ◽

Vol 87 (2) ◽

Author(s):

P. Kim ◽

R. Jorge ◽

W. Dorland

Keyword(s):

Magnetic Field ◽

Original Work ◽

Three Dimensional ◽

Radial Distance ◽

Analytical Form ◽

One Dimensional ◽

Modern Notation ◽

Magnetic Well ◽

First Time ◽

Dimensional Integral

A simplified analytical form of the on-axis magnetic well and Mercier's criterion for interchange instabilities for arbitrary three-dimensional magnetic field geometries is derived. For this purpose, a near-axis expansion based on a direct coordinate approach is used by expressing the toroidal magnetic flux in terms of powers of the radial distance to the magnetic axis. For the first time, the magnetic well and Mercier's criterion are then written as a one-dimensional integral with respect to the axis arclength. When compared with the original work of Mercier, the derivation here is presented using modern notation and in a more streamlined manner that highlights essential steps. Finally, these expressions are verified numerically using several quasisymmetric and non-quasisymmetric stellarator configurations including Wendelstein 7-X.

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Three-dimensional magnetic field reconstruction in the VKS experiment through Galerkin transforms

New Journal of Physics ◽

10.1088/1367-2630/13/2/023037 ◽

2011 ◽

Vol 13 (2) ◽

pp. 023037 ◽

Cited By ~ 6

Author(s):

J Boisson ◽

B Dubrulle

Keyword(s):

Magnetic Field ◽

Three Dimensional ◽

Field Reconstruction

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On the Fluctuation Induced Excess Conductivity in Stainless Steel Sheathed MgB2 Tapes

Journal of Materials ◽

10.1155/2013/898607 ◽

2013 ◽

Vol 2013 ◽

pp. 1-6 ◽

Cited By ~ 5

Author(s):

Suchitra Rajput ◽

Sujeet Chaudhary

Keyword(s):

Magnetic Field ◽

Experimental Data ◽

Stainless Steel ◽

Coherence Length ◽

Three Dimensional ◽

Excess Conductivity ◽

Scaling Functions ◽

Critical Fluctuations ◽

Scaling Models

We report on the analyses of fluctuation induced excess conductivity in the - behavior in the in situ prepared MgB2 tapes. The scaling functions for critical fluctuations are employed to investigate the excess conductivity of these tapes around transition. Two scaling models for excess conductivity in the absence of magnetic field, namely, first, Aslamazov and Larkin model, second, Lawrence and Doniach model, have been employed for the study. Fitting the experimental - data with these models indicates the three-dimensional nature of conduction of the carriers as opposed to the 2D character exhibited by the HTSCs. The estimated amplitude of coherence length from the fitted model is ~21 Å.

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Thermalization of synchrotron radiation from field-aligned currents

Laser and Particle Beams ◽

10.1017/s0263034600005413 ◽

1988 ◽

Vol 6 (3) ◽

pp. 493-501 ◽

Cited By ~ 8

Author(s):

William Peter ◽

Anthony L. Peratt

Keyword(s):

Magnetic Field ◽

Synchrotron Radiation ◽

Energy Density ◽

Radiation Spectrum ◽

Axial Magnetic Field ◽

Three Dimensional ◽

Synchrotron Emission ◽

Microwave Background ◽

Strong Function ◽

Current Filaments

Three-dimensional plasma simulations of interacting galactic-dimensioned current filaments show bursts of synchroton radiation of energy density 1·2 ×10−13 erg/cm3 which can be compared with the measured cosmic microwave background energy density of 1·5 × 10−13 erg/cm3. However, the synchrotron emission observed in the simulations is not blackbody. In this paper, we analyze the absorption of the synchrotron emission by the current filaments themselves (i.e., self-absorption) in order to investigate the thermalization of the emitted radiation. It is found that a large number of current filaments (>1031) are needed to make the radiation spectrum blackbody up to the observed measured frequency of 100 GHz. The radiation spectrum and the required number of current filaments is a strong function of the axial magnetic field in the filaments.

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