PGS: Lathrop on the core

The January, 2014, meeting of the Potomac Geophysical Society will be held January 16th at the Fort Myer Officers’ Club in Arlington, VA ( in the Glassed-in room in the Fife and Drum (main dining room).

 Daniel Lathrop

Title: Laboratory models of the Earth’s Core

 Abstract: Deep within the Earth, a turbulent rotating ocean of liquid iron generates the planetary magnetic field. That field changes over time in complicated ways. It has declined 10% in the last 160 years, fueling speculation that it may reverse. Unfortunately, we lack predictive scientific theories for the future evolution of the geodynamo. Experiments may play a role in the development of predictions, by enabling benchmarks of computer models not possible on direct Earth data. We have built a sequence of rapidly rotating turbulent liquid metal experiments that attempt to match parameters with the Earth’s core. Our observations highlight the importance of Coriolis effects and waves as well as magnetic forces in planets.



Daniel Lathrop received a B.A. in physics from the University of California at Berkeley in 1987, and a 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, and as Assistant Professor at Emory University. He joined the University of Maryland in 1997, the year he received a Presidential Early Career Award from the National Science Foundation. Daniel Lathrop is now Professor of Physics and Professor of Geology and a Fellow of the American Physical Society. His research in the Nonlinear Dynamics group at Maryland focuses on turbulent fluid flows, geomagnetism, and experiments on superfluid helium. Dr. Lathrop is also currently Associate Dean for Research for the College of Computer, Mathematical and Natural Sciences, and served as the Director of the Institute for Research in Electronics and Applied Physics from 2006 to 2012. He received the Stanley Corrsin Award in 2012 from the American Physical Society for this work in quantum fluids.

Meeting Room and Dining Arrangements: We now meet in the glassed-in room at the back of the main dining room—The Fife and Drum. We order individually from the Club menu, which has a nice variety of dinner offerings. We pay a single bill (I pay it with my Officers Club credit card), so we collect at least $25 from each diner with the agreement, that if one orders more than $20 in food and drink, he adds the amount over $20 to his contribution. The $5 overcharge goes to the Room Fee, Tax, Gratuity, and the Speaker’s Dinner. We collect on the Honor System. We did this throughout the last year, and it worked well. This room change and use of the menu have greatly reduced the loss that we have incurred in the past for having fewer than 20 people dining, and the change has preserved the viability of using the Officers Club for our meetings.

Reception at 6:00. Order Dinner at 7:00. Talk at 8:30 PM. Please note that the meal orders will be taken at 7:00. Allow 15 minutes for security entering Ft. Myer as all civilian vehicles are searched. To ensure access to and from Fort Myer use the Hatfield Gate, open 24 hours a day ( Reservations are not necessary, however, we need a head count, so, if you wish to attend dinner ($25), please inform Bob Fraser at 540-888-3001 or via E-mail at If you wish, please feel free to attend the talk without dinner. Non-members and guests are welcome. Visit the PGS web site at for new meeting announcements, etc. Please send changes of address or email to


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