An experimental investigation of current production by means of rotating magnetic fields

An investigation of current production by means of a rotating magnetic field is made in an experiment in which the technique is used to generate a theta-pinch- like distribution of field and plasma. Detailed measurements are made of both the generated unidirectional azimuthal electron current and the penetration of the rotating field into the plasma. The experimental results support the theoretical prediction that a threshold value of the amplitude of the applied rotating field exists for setting the electrons into rotation.

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Power and Momentum Relations in Rotating Magnetic Field Current Drive

Australian Journal of Physics ◽

10.1071/ph840509 ◽

1984 ◽

Vol 37 (5) ◽

pp. 509 ◽

Cited By ~ 13

Author(s):

WN Hugrass

Keyword(s):

Magnetic Field ◽

Angular Momentum ◽

Magnetic Fields ◽

Phase Velocity ◽

Current Drive ◽

Rotating Magnetic Field ◽

Plasma Current ◽

Rotating Magnetic Fields ◽

Frequency Source ◽

Rotating Field

The use of rotating magnetic fields (RMF) to drive steady currents in plasmas involves a transfer of energy and angular momentum from the radio frequency source feeding the rotating field coils to the plasma. The. power-torque relationships in RMF systems are discussed and the analogy between RMF current drive and the polyphase induction motor is explained. The general relationship between the energy and angular momentum transfer is utilized to calculate the efficiency of the RMF plasma current drive. It is found that relatively high efficiencies can be achieved in RMF current drive because of the low phase velocity and small slip between the rotating field and the electron fluid.

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Frequency-dependent conversion of the torque of a rotating magnetic field on a ferrofluid confined in a spherical cavity

Soft Matter ◽

10.1039/c9sm01311c ◽

2019 ◽

Vol 15 (44) ◽

pp. 9018-9030

Author(s):

Klaus D. Usadel ◽

Anastasiya Storozhenko ◽

Igor Arefyev ◽

Hajnalka Nádasi ◽

Torsten Trittel ◽

...

Keyword(s):

Magnetic Field ◽

Magnetic Nanoparticles ◽

Magnetic Fields ◽

Spherical Cavity ◽

Rotating Magnetic Field ◽

Rotating Magnetic Fields ◽

Frequency Dependent

The dynamics of magnetic nanoparticles in rotating magnetic fields is studied both experimentally and theoretically.

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3D motion of flexible ferromagnetic filaments under a rotating magnetic field

Soft Matter ◽

10.1039/d0sm00403k ◽

2020 ◽

Vol 16 (18) ◽

pp. 4477-4483 ◽

Cited By ~ 2

Author(s):

Abdelqader Zaben ◽

Guntars Kitenbergs ◽

Andrejs Cēbers

Keyword(s):

Magnetic Field ◽

Numerical Study ◽

Rotating Magnetic Field ◽

3D Motion ◽

Rotating Field

Experimental and numerical study of flexible ferromagnetic filaments reveal different regimes, when subjected to a 2D rotating field. The filaments were found to have a 3D motion at higher frequencies.

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Investigation of mixing time in liquid under influence of rotating magnetic field

Chemical and Process Engineering ◽

10.1515/cpe-2017-0044 ◽

2017 ◽

Vol 38 (4) ◽

pp. 555-565

Author(s):

Alicja Przybył ◽

Rafał Rakoczy ◽

Maciej Konopacki ◽

Marian Kordas ◽

Radosław Drozd ◽

...

Keyword(s):

Magnetic Field ◽

Experimental Investigation ◽

Reynolds Number ◽

Mixing Time ◽

Rotating Magnetic Field ◽

Homogenization Time ◽

Set Up ◽

The Relationship ◽

The Magnetic Field

Abstract The aim of the study was to present an experimental investigation of the influence of the RMF on mixing time. The obtained results suggest that the homogenization time for the tested experimental set-up depending on the frequency of the RMF can be worked out by means of the relationship between the dimensionless mixing time number and the Reynolds number. It was shown that the magnetic field can be applied successfully to mixing liquids.

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Steady-state solutions for the penetration of a rotating magnetic field into a plasma column

Journal of Plasma Physics ◽

10.1017/s0022377800010837 ◽

1981 ◽

Vol 26 (3) ◽

pp. 441-453 ◽

Cited By ~ 81

Author(s):

Ieuan R. Jones ◽

Waheed N. Hugrass

Keyword(s):

Magnetic Field ◽

Steady State ◽

Plasma Column ◽

Skin Effect ◽

Rotation Frequency ◽

Rotating Magnetic Field ◽

Electron Current ◽

Plasma Cylinder ◽

Resistive Plasma ◽

Steady State Solutions

The penetration of an externally applied rotating magnetic field into a plasma cylinder is examined. Steady-state solutions of an appropriate set of magneto-fluid equations show that, provided the amplitude and rotation frequency of the field are suitably chosen, the penetration is not limited by the usual classical skin effect. The enhanced penetration of the rotating field is accompanied by the generation of a unidirectional azimuthal electron current which is totally absent in a purely resistive plasma cylinder.

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FLEXIBLE FERROMAGNETIC FILAMENTS AS ARTIFICIAL CILIA

International Journal of Modern Physics B ◽

10.1142/s0217979211058420 ◽

2011 ◽

Vol 25 (07) ◽

pp. 935-941 ◽

Cited By ~ 4

Author(s):

A. CĒBERS ◽

R. LIVANOVIČS

Keyword(s):

Magnetic Field ◽

Numerical Algorithm ◽

Rotating Magnetic Field ◽

Artificial Cilia ◽

Fixed End ◽

Rotating Field

The model of an artificial cilia as a flexible ferromagnetic filament in a rotating magnetic field is proposed. Numerical algorithm for the simulation of its behavior is developed and the characteristic shapes of the filament with one fixed end under the action of a rotating field are found. It is concluded that ferromagnetic filaments may be used as mixers in microfluidics.

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Control of the Macrosegregations during Solidification of a Binary Alloy by Means of a AC Magnetic Field

Materials Science Forum ◽

10.4028/www.scientific.net/msf.508.163 ◽

2006 ◽

Vol 508 ◽

pp. 163-168 ◽

Cited By ~ 11

Author(s):

Xiao Dong Wang ◽

A. Ciobanas ◽

Florin Baltaretu ◽

Anne Marie Bianchi ◽

Yves Fautrelle

Keyword(s):

Magnetic Field ◽

Magnetic Fields ◽

Mushy Zone ◽

Binary Alloy ◽

Solidification Front ◽

Laminar Flows ◽

Rotating Magnetic Field ◽

Moderate Intensity ◽

Mushy Region ◽

Rotating Magnetic Fields

A numerical model aimed at simulating the segregations during the columnar solidification of a binary alloy is used to investigate the effects of a forced convection. Our objective is to study how the segregation characteristics in the mushy zone are influenced by laminar flows driven both by buoyancy and by AC fields of moderate intensity. Various types of magnetic fields have been tested, namely travelling, rotating magnetic field and slowly modulated electromagnetic forces. The calculations have been achieved on two types of alloys, namely tin-lead and aluminiumsilicon. It is shown that the flow configuration changes the segregation pattern. The change comes from the coupling between the liquid flow and the top of the mushy zone via the pressure distribution along the solidification front. The pressure difference along the front drives a mush flow, which transports the solute in the mushy region. Another interesting type of travelling magnetic field has been tested. It consists of a slowly modulated travelling magnetic field. It is shown that in a certain range of values of the modulation period, the channels are almost suppressed. The normal macrosegregation remains, but the averaged segregation in the mushy zone is weaker than in the natural convection case. The optimal period depends on the electromagnetic force strength as well as the cooling rate. The latter phenomenon cannot occur in the case of rotating magnetic fields, since in that configuration the sign of the pressure gradient along the solidification front remains unchanged. Recent solidification experiments with electromagnetic stirring confirm the predicted macrosegregation patterns.

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An experimental investigation into the behaviour of a spherical plasma resonance probe in a magnetic field

Journal of Plasma Physics ◽

10.1017/s0022377800003445 ◽

1967 ◽

Vol 1 (4) ◽

pp. 451-462

Author(s):

P. G. Davies

Keyword(s):

Magnetic Field ◽

Experimental Investigation ◽

Discharge Current ◽

Plasma Source ◽

Simplified Model ◽

Main Peak ◽

Electron Current ◽

Plasma Probe ◽

Spherical Plasma ◽

The Magnetic Field

The rectified electron current to a non-magnetic and to a magnetic spherical plasma probe has been investigated as a function of the frequency of the applied alternating potential, the discharge current in the plasma source and the magnitude of the magnetic field produced by a Helmholtz coil pair. The frequency at the main peak in the rectified current was found to be always greater than the gyro- frequency and to lie within a range of frequency predicted by Crawford from an analysis of a simplified model. The results of this laboratory work have been applied to a rocket-borne experiment on resonance rectification previously carried out by R.S.R.S.

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Semiconductor Crystal Growth by the Vertical Bridgman Process With Transverse Rotating Magnetic Fields

Journal of Heat Transfer ◽

10.1115/1.2352790 ◽

2006 ◽

Vol 129 (2) ◽

pp. 241-243 ◽

Cited By ~ 5

Author(s):

X. Wang ◽

N. Ma

Keyword(s):

Magnetic Field ◽

Crystal Growth ◽

Magnetic Fields ◽

Applied Magnetic Field ◽

Rotating Magnetic Field ◽

Semiconductor Crystal ◽

Rotating Magnetic Fields ◽

Electrically Conducting ◽

Vertical Bridgman ◽

Bridgman Process

During the vertical Bridgman process, a single semiconductor crystal is grown by the solidification of an initially molten semiconductor contained in an ampoule. The motion of the electrically conducting molten semiconductor can be controlled with an externally applied magnetic field. This paper treats the flow of a molten semiconductor and the dopant transport during the vertical Bridgman process with a periodic transverse or rotating magnetic field. The frequency of the externally applied magnetic field is sufficiently low that this field penetrates throughout the molten semiconductor. Dopant distributions in the crystal are presented.

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