MHD Modeling of Density Limit Disruptions in Tokamaks

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Motivated by synthesis of new antiferromagnetic compounds with weak exchange coupling, a study of high magnetic field properties of the Heisenberg model on a square-lattice is undertaken here. Ordered spins at zero temperature cant toward the field direction inducing coupling of transverse and longitudinal magnon modes. Resulting interactions renormalize the ground-state energy and the dispersion relation below a threshold field H∗ = 0.76Hsat, where one-magnon excitations starts to become unstable and acqui

In small area capacitive reactors, the rf and dc components of the plasma potential can be assumed to be uniform over all the plasma bulk because of the low plasma resistivity. In large area reactors, however, the rf plasma potential can vary over a long range across the reactor due to rf current flow and the nonzero plasma impedance. A perturbation in rf plasma potential, due to electrode edge asymmetry or the boundary of a dielectric substrate, propagates along the resistive plasma between capacitive shea

We study the dynamic motion of magnetic structures composed of micron-size ferromagnetic particles. The supraparticle structures are retained in a microfluidic channel by a local oscillating magnetic field while subjected to a viscous liquid flow. We analyze the position of the magnetic structures as a function of the flow velocity and of the frequency and amplitude of the magnetic field. We also study the conditions for release of the magnetic structures from the localized magnetic field region.

We have investigated the effect of different ion cyclotron resonance frequency (ICRF) heating schemes, of error field modes, of the plasma shape and edge magnetic shear, and of the ion delB drift direction on the stability of Alfven eigenmodes (AEs). The use of multi-frequency or 2nd harmonic minority ICRF heating at high plasma density gives rise to a lower fast ion pressure gradient in the plasma core and to a reduced mode activity in the Alfven frequency range. Externally excited low-amplitude error fiel

In this paper the effects of the magnetic self-field on the transport properties of a multi-layer high-Tc superconducting (HTS) cable are investigated by means of 2D finite element method (FEM) simulations. Analyzed is a 3-layer HTS cable, but the developed methods can be used for a different number of layers. The superconductor is described by the non-linear power-law relation E=Ec(J/Jc)^n, where the parameters Jc and n depend on the magnetic field experienced by the material. This dependence decreases the

Conventional Hall devices are widely employed to measure magnetic fields produced by millimetre sized (or larger) current-caring conductors or permanent magnets with a standard active area of about (100 um)^2. Micro-Hall sensors have recently emerged as a powerful and sensitive tool for the investigation of local magnetic field properties of the micro and nano-structures. The conventional Hall effect devices are based on non-magnetic materials (typically semiconductors e.g: AlGaAs/GaAs and InSb or semimetal

We study the effect of a magnetic field (applied along the c axis) on the low-energy, incommensurate magnetic fluctuations in superconducting La1.82Sr0.18CuO4. The incommensurate peaks at 9 meV, which in zero field were previously shown to sharpen in q on cooling below T-c [T. E. Mason , Phys. Rev. Lett. 77, 1604 (1996)], are found to broaden in q when a field of 10 T is applied. The applied field also causes scattered intensity to shift into the spin gap. We point out that the response at 9 meV, though occ

We present an exact model for determining the cogging torque in a brushless DC (BLDC) motor. It is based on the conformal mapping (CM) method, by which the motor configuration is transformed to a configuration where the magnetic field can be determined. Then, by integrating the field over the stator surface, the cogging torque is determined. By varying some motor parameters, which is easy to do, an optimal configuration with the minimal cogging torque is obtained. We have confirmed the results by the finite

Using the SULTAN test facility the d.c. behaviour of three subsize NbTi cable-in-conduit (CIC) conductors has been studied. The d.c. performance of the cables is compared with the critical currents and the current sharing temperatures expected from the strand data. As a basis for this comparison the critical current of the NbTi strands has been measured in the temperature range of 4.2-6.5 K in magnetic fields of up to 7.5 T. The d.c. performance of the NbTi subsize conductors has been found to be not signif

Planar magnetic sensor, made in particular via CMOS techniques on a semiconductor substrate (1) of for example parallelepiped shape. It includes an amorphous ferromagnetic core (10) in the shape of a Greek cross which occupies the two diagonals of the square defined by the outer contour (90) of the excitation coil (9), the latter being made in the form of a planar winding of square shape. One thus measures, via flat detection coils (70, 80 and 71, 81) which are mounted in series and in a differential arrang

In certain power applications, Bi-2223 conductors carrying AC current will be subjected to external magnetic fields, whose orientation and conductor’s geometry are of major significance for the AC loss magnitude. This paper investigates the influence of the geometry and aspect ratio of non-twisted Bi-2223 conductors in reducing the AC loss for such applications. A numerical model of high-Tc materials has been used in FEM simulations. The model incorporates power-law E-J characteristics with Jc defined by bo

Experimental data characterizing indoor electric and magnetic fields radiated by power line communication (PLC) systems and used for the calculation of a local transfer function (coupling factor) are presented. It is shown that the indirect determination of electric field using magnetic field measurements and assuming a plane wave approximation may result in an underestimation of the electric field. Additionally, it is shown that the radiated field magnitudes vary significantly as a function of the position

MHD Modeling of Density Limit Disruptions in Tokamaks

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Effect of Magnetic Field on Dynamics of Antiferromagnets

Nonuniform radio-frequency plasma potential due to edge asymmetry in large-area radio-frequency reactors

Dynamics of magnetically retained supraparticle structures in a liquid flow

Alfven mode stability and wave-particle interaction in the JET tokamak: prospects for scenario development and control schemes in burning plasma experiments

Numerical Analysis of the Effects of the Magnetic Self-Field on the Transport Properties of a Multilayer HTS Cable

Bismuth Micro and Nano Hall Sensors on Photo-plastic Cantilevers for Scanning Hall Probe Microscopy

Evidence for an incommensurate magnetic resonance in La2-xSrxCuO4

Reducing the cogging torque in brushless DC motors by using conformal mappings

DC behaviour of NbTi cable-in-conduit conductors for ITER-FEAT

Integrated planar fluxgate sensor

Geometry considerations for transport current applications of Bi-2223 conductors with anisotropic Jc(B) in external magnetic field

Indoor radiated emission associated with power line communication systems