Study of Magnetohydrodynamic Surface Waves on Liquid Gallium

Technical Report · Thu May 13 04:00:00 EDT 2004

DOI:https://doi.org/10.2172/827940· OSTI ID:827940

Ji, Hantao ^[1]; Fox, William; Pace, David; Rappaport, H L

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1. Princeton Plasma Physics Laboratory

Magnetohydrodynamic (MHD) surface waves on liquid gallium are studied theoretically and experimentally in the small magnetic Reynolds number limit. A linear dispersion relation is derived when a horizontal magnetic field and a horizontal electric current is imposed. No wave damping is found in the shallow liquid limit while waves always damp in the deep liquid limit with a magnetic field parallel to the propagation direction. When the magnetic field is weak, waves are weakly damped and the real part of the dispersion is unaffected, while in the opposite limit waves are strongly damped with shortened wavelengths. In a table-top experiment, planar MHD surface waves on liquid gallium are studied in detail in the regime of weak magnetic field and deep liquid. A non-invasive diagnostic accurately measures surface waves at multiple locations by reflecting an array of lasers off the surface onto a screen, which is recorded by an Intensified-CCD camera. The measured dispersion relation is consistent with the linear theory with a reduced surface tension likely due to surface oxidation. In excellent agreement with linear theory, it is observed that surface waves are damped only when a horizontal magnetic field is imposed parallel to the propagation direction. No damping is observed under a perpendicular magnetic field. The existence of strong wave damping even without magnetic field suggests the importance of the surface oxide layer. Implications to the liquid metal wall concept in fusion reactors, especially on the wave damping and a Rayleigh-Taylor instability when the Lorentz force is used to support liquid metal layer against gravity, are discussed.

• Research Organization: Princeton Plasma Physics Lab., Princeton, NJ (US)
• Sponsoring Organization: USDOE Office of Science (SC) (US)
• DOE Contract Number: AC02-76CH03073
• OSTI ID: 827940
• Report Number(s): PPPL-3953
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
DAMPING
DISPERSION RELATIONS
ELECTRIC CURRENTS
FUSION REACTORS
DESIGN
GALLIUM
LASERS
LIQUID METAL
LIQUID METALS
LORENTZ FORCE
MAGNETIC FIELDS
MAGNETIC REYNOLDS NUMBER
MAGNETOHYDRODYNAMICS
MAGNETOHYDRODYNAMICS (MHD)
OXIDATION
OXIDES
RAYLEIGH-TAYLOR INSTABILITY
SURFACE TENSION
THERMONUCLEAR REACTORS
WAVELENGTHS