Date of Award

6-2010

Document Type

Union College Only

Degree Name

Bachelor of Science

Department

Physics and Astronomy

First Advisor

Scott LaBrake

Language

English

Keywords

field, magnetic, surface, flow, free

Abstract

Characterizing turbulent free-surface magnetohydrodynamic (MHD) flow in a region with a strong magnetic field is critical to understanding some astrophysical phenomena as well as designing a liquid-metal first wall diverter in a fusion reactor. To isolate the effect of a magnetic field on free-surface MHD, an experiment was performed in which liquid gallium flowed down a wide aspect ratio channel perpendicular to a uniform, static, magnetic field of up to 2 kG. We measured disturbances in the flow at two locations by tracking the position of laser beam reflections from the liquid’s surface with position sensitive photodiodes as a function of time. Given the two time-series and the distance between the measured locations on the surface, we estimated the local wavenumber and frequency spectra using two-point correlation analysis. Evidence from these spectra indicates that turbulence and wave features parallel to the magnetic field are largely damped as the magnetic field increases, thereby reducing the turbulence from three dimensions to two.

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