Absorption of ultrasound by a magnetic fluid in a rotating magnetic field

Experimental results on the absorption of ultrasound by a magnetic fluid in a rotating magnetic field have been obtained for the first time. It is shown that the lag of the angular dependence of the ultrasonic absorption coefficient by a magnetic fluid in the range of magnetic field rotation frequencies fH = 0.056 - 280 mHz at T = 295 K is not observed within the limits of observational errors. Similar results were observed for both low-viscosity and high-viscosity magnetic fluids. Tables 1, Figs 6, Refs 39.

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Magnetic field rotation at high solar latitudes

Solar Physics ◽

10.1007/bf00951832 ◽

1978 ◽

Vol 59 (2) ◽

pp. 243-248 ◽

Cited By ~ 7

Author(s):

Robert Howard

Keyword(s):

Magnetic Field ◽

Magnetic Field Rotation ◽

Field Rotation

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Characterization of magnetic field rotation of steel sheet under uniaxial stress

Measurement ◽

10.1016/j.measurement.2012.01.013 ◽

2012 ◽

Vol 45 (5) ◽

pp. 1239-1245 ◽

Cited By ~ 4

Author(s):

Shih-Kang Kuo ◽

Sheng-Yang Lin ◽

Chen-Yuan Lu

Keyword(s):

Magnetic Field ◽

Steel Sheet ◽

Uniaxial Stress ◽

Magnetic Field Rotation ◽

Field Rotation

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Swirling Flow of Magnetic Fluid in Multi-Pole Rotating Magnetic Field

Volume 2: Symposia, Parts A, B, and C ◽

10.1115/fedsm2003-45040 ◽

2003 ◽

Author(s):

Kenichi Kamioka ◽

Ryuichiro Yamane

Keyword(s):

Magnetic Field ◽

Fluid Flow ◽

Circular Cylinder ◽

Phase Velocity ◽

Magnetic Fluid ◽

Swirling Flow ◽

Peak Velocity ◽

Rotating Magnetic Field ◽

Outer Periphery ◽

The Magnetic Field

The experiments are conducted on the magnetic fluid flow induced by the multi-pole rotating magnetic field in a circular cylinder. The numbers of poles are two, four, six, eight and twelve. The applied electric current and frequency are 2∼6 A and 20∼60 Hz, respectively. The peak velocity of the flow increases with the increase in the strength and the phase velocity of the magnetic field. As the increase in the number of poles, the flow shifts to the outer periphery.

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Theory of Protostellar Disk Formation

Proceedings of the International Astronomical Union ◽

10.1017/s1743921316007377 ◽

2015 ◽

Vol 11 (S315) ◽

pp. 118-125

Author(s):

Zhi-Yun Li ◽

Ruben Krasnopolsky ◽

Hsien Shang

Keyword(s):

Magnetic Field ◽

Rotation Axis ◽

Misalignment Angle ◽

Disk Formation ◽

Magnetic Field Rotation ◽

Ideal Mhd ◽

Magnetic Braking ◽

Field Rotation ◽

Field Lines ◽

Protostellar Collapse

AbstractHow large, 100-AU scale, rotationally supported disks form around protostars remains unsettled, both observationally and theoretically. In this contribution, we discuss the theoretical difficulties with disk formation in the presence of a dynamically significant magnetic field and their possible resolutions. These difficulties are caused by the concentration of magnetic field lines close to the forming star by protostellar collapse, and the strong magnetic braking associated with the concentrated field. Possible resolutions include magnetic field-rotation axis misalignment, non-ideal MHD effects, and turbulence. The field-rotation misalignment has been shown to promote disk formation, especially when the field is relatively weak and the misalignment angle is relatively large. Non-ideal MHD effects can enable the formation of small disks at early times. How such disks grow at later times remains to be fully quantified. Turbulence has been found to enable disk formation in a number of simulations, but the exact reason for its beneficial effect is debated.

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