Magnetoelastic Buckling of Thin Magnetically Soft Plates in Cylindrical Mode

1974 ◽  
Vol 41 (1) ◽  
pp. 145-150 ◽  
Author(s):  
J. M. Dalrymple ◽  
M. O. Peach ◽  
G. L. Viegelahn
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
Rectangular Plate ◽  
Empirical Formula ◽  
Uniform Magnetic Field ◽  
Critical Value ◽  
Elliptical Plate ◽  
Wide Face ◽  
Magnetically Soft Material ◽  
Plate Width

When a plate of magnetically soft material is supported with its wide face normal to a uniform magnetic field, it will buckle when the field reaches a critical value. It is shown theoretically that the critical buckling field for a “half-restrained” rectangular plate should be 0.833 of that for a half-restrained elliptical plate of identical dimensions and material. Limited experimental data support this conclusion. The effect of plate width upon critical buckling field is investigated experimentally and an empirical formula is presented which fits the data reasonably well.

Experimental and Theoretical Study on Magnetoelastic Buckling of a Ferromagnetic Cantilevered Beam-Plate

1978 ◽  
Vol 45 (2) ◽  
pp. 355-360 ◽  
Author(s):  
K. Miya ◽  
K. Hara ◽  
K. Someya
Keyword(s):  
Magnetic Field ◽  
Theoretical Study ◽  
Critical Value ◽  
The Finite Element Method ◽  
Wide Face ◽  
Field Distortion ◽  
Cantilevered Beam ◽  
Magnetically Soft Material ◽  
Experimental Values ◽  
The Magnetic Field

When a cantilever of magnetically soft material is inserted with its wide face normal to a uniform magnetic field and the magnetic field is increased to a critical value the cantilever will buckle. The experimental magnetoelastic buckling fields and the theoretical ones differ by a factor of two. A magnetic field distortion near an edge of the specimen is here evaluated based on the finite-element method and the results are applied to the experimental results so as to explain the discrepancy between the experiment and the theory. The corrected experimental values are within 15 percent of the theoretical values. The effect of demagnetization on the buckling field is here demonstrated as well as the effect of specimen dimensions.

Magnetoelastic Buckling of Beams and Thin Plates of Magnetically Soft Material

1972 ◽  
Vol 39 (2) ◽  
pp. 451-455 ◽  
Author(s):  
D. V. Wallerstein ◽  
M. O. Peach
Keyword(s):  
Magnetic Field ◽  
Theoretical Result ◽  
Cantilever Beam ◽  
Uniform Magnetic Field ◽  
Critical Value ◽  
Soft Material ◽  
Thin Plates ◽  
Magnetically Soft Material ◽  
Plate Geometry ◽  
Special Case

When a plate of magnetically soft material is supported with its wide surface normal to a uniform magnetic field, it will buckle when the field reaches a critical value. This paper formulates the problem quite generally for thin plates (including beams) and carries the solution as far as can be done without making specific assumptions as to plate geometry and constraints. The special case of wide cantilever beam, considered earlier by Moon and Pao, is carried through in detail. It is shown that if their theoretical result is modified to take account of the increased field intensity caused by the plate, agreement with experiment is within 20 percent.

scholarly journals Effect of a stochastic electric field on plasma confinement in FTU

2016 ◽  
Vol 31 (02) ◽  
pp. 1650005 ◽  
Author(s):  
Roberto Martorelli ◽  
Giovanni Montani ◽  
Nakia Carlevaro
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
Electric Field ◽  
Uniform Magnetic Field ◽  
Planck Equation ◽  
Plasma Confinement ◽  
Stochastic Field ◽  
Magnetically Confined ◽  
The Magnetic Field ◽  
Plasma Profile

We discuss a stochastic model for the behavior of electrons in a magnetically confined plasma having axial symmetry. The aim of the work is to provide an explanation for the density limit observed in the Frascati Tokamak Upgrade (FTU) machine. The dynamical framework deals with an electron embedded in a stationary and uniform magnetic field and affected by an orthogonal random electric field. The behavior of the average plasma profile is determined by the appropriate Fokker–Planck equation associated to the considered model and the disruptive effects of the stochastic electric field are shown. The comparison between the addressed model and the experimental data allows to fix the relevant spatial scale of such a stochastic field. It is found to be of the order of the Tokamak micro-physics scale, i.e. few millimeters. Moreover, it is clarified how the diffusion process outlines a dependence on the magnetic field as [Formula: see text].

scholarly journals INFLUENCE OF A UNIFORM MAGNETIC FIELD ON DYNAMICAL CHIRAL SYMMETRY BREAKING IN QED3

2012 ◽  
Vol 27 (09) ◽  
pp. 1250026 ◽  
Author(s):  
JIAN-FENG LI ◽  
HONG-TAO FENG ◽  
YU JIANG ◽  
WEI-MIN SUN ◽  
HONG-SHI ZONG
Keyword(s):  
Magnetic Field ◽  
High Temperature ◽  
Symmetry Breaking ◽  
Chiral Symmetry ◽  
Uniform Magnetic Field ◽  
Cuprate Superconductors ◽  
Chiral Symmetry Breaking ◽  
Critical Value ◽  
Dynamical Chiral Symmetry Breaking ◽  
The Magnetic Field

We study dynamical chiral symmetry breaking (DCSB) in an effective QED3 theory of d-wave high temperature cuprate superconductors under a uniform magnetic field. At zero temperature, the external magnetic field induces a mixed state by generating vortices in the condensate of charged holons. The growing magnetic field suppresses the superfluid density and thus reduces the gauge field mass which is opened via the Anderson–Higgs mechanism. By numerically solving the Dyson–Schwinger gap equation, we show that the massless fermions acquires a dynamical gap through DCSB mechanism when the magnetic field strength H is above a critical value H c and the fermion flavors N is below a critical value N c . Further, it is found that both N c and the dynamical fermion gap increase as the magnetic field H grows. It is expected that our result can be tested in phenomena in high temperature cuprate superconductors.

Vibration and Dynamic Instability of a Beam-Plate in a Transverse Magnetic Field

1969 ◽  
Vol 36 (1) ◽  
pp. 92-100 ◽  
Author(s):  
F. C. Moon ◽  
Yih-Hsing Pao
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
Mathematical Model ◽  
Natural Frequency ◽  
Dynamic Instability ◽  
Critical Value ◽  
Transverse Magnetic ◽  
Axial Forces ◽  
Oscillating Magnetic Field ◽  
Theoretical Results

Experiments show that the natural frequency of a beam-plate in a transverse static magnetic field decreases to near zero as the field attains a critical value which causes the same plate to buckle statically. Under an oscillating magnetic field the beam-plate is observed to become unstable and perform parametrically excited oscillations. A mathematical model based on a quasistatic solution for the magnetization in the deformed plate is proposed. The theoretical results agree very well with the experimental data. It is shown that the phenomena are analogous to those for a beam-column under static and dynamic axial forces.

Effect of finite ion Larmor radius on the Kelvin–Helmholtz instability

1978 ◽  
Vol 20 (2) ◽  
pp. 149-160 ◽  
Author(s):  
Hirosh Nagano
Keyword(s):  
Magnetic Field ◽  
Flow Velocity ◽  
Wave Vector ◽  
Uniform Magnetic Field ◽  
Critical Value ◽  
Larmor Radius ◽  
Helmholtz Instability ◽  
Finite Larmor Radius ◽  
Compressible Plasma ◽  
The Difference

The effect of finite ion Larmor radius on the Kelvin–Helmholtz instability is investigated in the cases of an incompressible and a compressible plasma. When a wave vector is perpendicular to a uniform magnetic field, the effect of finite Larmor radius (FLR) stabilizes perturbations with a wavenumber exceeding a critical value, while there exists another case that the FLR effect destabilizes still more than the usual MHD approximation. The difference between these cases is decided from the configuration of flow velocity and magnetic field. When a wave vector is parallel to a magnetic field, the FLR effect tends to stabilize perturbations with a larger wavenumber.

scholarly journals Laser-produced plasma expansion in a uniform magnetic field

1992 ◽  
Vol 10 (4) ◽  
pp. 723-735 ◽  
Author(s):  
U. S. Begimkulov ◽  
B. A. Bryunetkin ◽  
V. M. Dyakin ◽  
G. A. Koldashov ◽  
S. N. Priyatkin ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
Numerical Analysis ◽  
Uniform Magnetic Field ◽  
Plasma Jet ◽  
Plasma Cloud ◽  
Plasma Expansion ◽  
Laser Produced Plasma ◽  
Cloud Evolution ◽  
The Magnetic Field

Laser-produced plasma cloud evolution in a magnetic field is investigated up to 3 kg using photographs and spectroheliograms. Generation of a plasma jet, oriented across the magnetic field, was detected, whose emission increases with the field strength and is more distinct for multicharged ions. The effects of the field on the interaction of closely located laser-produced plasma clouds were studied as well. The results of numerical analysis comply with experimental data on plasma behavior in the magnetic field.

Magnetoelastic Buckling of a Thin Plate

1968 ◽  
Vol 35 (1) ◽  
pp. 53-58 ◽  
Author(s):  
F. C. Moon ◽  
Yih-Hsing Pao
Keyword(s):  
Magnetic Field ◽  
Axial Load ◽  
Uniform Magnetic Field ◽  
Field Experiments ◽  
Equilibrium Configuration ◽  
Critical Value ◽  
Transverse Magnetic ◽  
Field Equations ◽  
Magnetostatic Field ◽  
Characteristic Values

The instability of a column under axial load is well known. A similar phenomenon is discussed in this paper for a beam-plate in a transverse magnetic field. Experiments show that the beam may buckle (in the sense of an Euler column) when the uniform magnetic field strength reaches a critical value. A mathematical model is proposed with distributed magnetic torques along the plate. A nontrivial adjacent equilibrium configuration satisfying the magnetostatic field equations is shown to exist for characteristic values of the external magnetic field. Results as predicted from this model compare favorably with experiments.

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