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Goddard Space Flight Center, Greenbelt, Maryland 20771

ENGINEERING COLLOQUIUM

Monday, September 15, 2008 / 3:30 PM, Building 3 Auditorium

photo of large stainless steel sphere in lab

Daniel P. Lathrop

"Engineering Challenges in Building Laboratory Models of Planetary Cores "

ABSTRACT -- This talk will address engineering challenges in rotating liquid sodium experiments. The University of Maryland Geophysics laboratory is using these to model Earth's and other planetary cores. A sequence of experiments has been built in the last decade of increasing size and input power. The largest apparatus uses a three meter (10’) diameter stainless steel outer sphere and a one meter diameter inner sphere. They are spun by two 250 kW (350 Hp) electric motors. Tests are underway with the apparatus filled with water, but the system will be run later this year with liquid sodium. All told, the full sphere will weigh 26 tons (not including frame and motors). At its operational spin rate, 240 RPM, the speed of the sphere's equator will be 80 miles per hour. The system includes a thermal control system with heaters (operating temperature is 110 C) and cooling.

The experiment is designed to provide insights into the complex processes that create Earth's magnetic field. The field is presumed to be the result of interacting fluid and magnetic currents in the Earth’s liquid iron outer core. Because of the nonlinear, turbulent nature of these flows, they cannot be easily modeled mathematically or computationally. Experimental measurements can yield insight into the processes in planetary interiors.

SPEAKER -- Daniel Lathrop is Director of the Institute for Research in Electronics and Applied Physics at the University of Maryland, and part of the Nonlinear Dynamics and Chaos group. Topics studied in Dr. Lathrop’s lab include superfluid turbulence, nonlinear surface waves, and the interaction of magnetic fields with rotating turbulence in the Earth's core. His studies of the magnetic dynamo effect in Earth's core involve the construction of rotating spheres filled with molten sodium.

He is co-inventor of a tidal power generator, developed while serving as a technical consultant to Tidal Electric, Inc. Dr. Lathrop received the B.A. in physics from the University of California at Berkeley in 1987, and the Ph.D. in physics from the University of Texas at Austin in 1991. He then served at Yale University as a postdoctoral fellow, research affiliate, and lecturer. While at Emory University, he was recognized by Phi Beta Kappa for excellence in teaching in both 1995 and 1997. He joined the University of Maryland in 1997, the year he received a Presidential Early Career Award from the NSF. He is currently Professor in two departments, Physics and Geology, and in two Institutes, the Institute for Research in Electronics and Applied Physics and the Institute for Physical Sciences and Technology. In 2005, he was elected a fellow of the American Physical Society.




Engineering Colloquium home page: https://ecolloq.gsfc.nasa.gov