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Turbulent Liquid Metal Dynamo Experiments

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Date and time Nov 30, 2006
from 04:10 PM to 05:00 PM
Location McLennan Physics (MP) 102
Host Ue-Li Pen

Cary Forest

The self-generation of magnetic fields in planets and stars -- the dynamo effect -- is a long-standing problem of magnetohydrodynamics and plasma physics. Until recently, research on the self-excitation process has been primarily theoretical. In this talk, I will begin with a tutorial on how magnetic fields are generated in planets and stars, describing the "Standard Model" of self-excitation known as the alpha-omega dynamo. In this model, axisymmetric differential rotation can produce the majority of the magnetic field, but some non-axisymmetric, turbulence driven currents are also necessary. Understanding the conversion of turbulent kinetic energy in the fluid motion into electrical currents and thus magnetic fields, is a major challenge for both experiments and theory at this time. I will then report on recent results from a 1 meter diameter, spherical, liquid sodium dynamo experiment at the University of Wisconsin, in which the first clear evidence for these turbulence driven currents has been observed.

Forest-fig.jpg

Multimedia

MP3 recording of talk
PDF presentation file
PPT presentation file (with voice synchronization)

Contact Name Ue-Li Pen
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