"The Three Meter Experiment: Achieving an Earth-like Dynamo in the Lab"

by Elaine Jaross

Friday, February 3, 2023 -- 12:00 p.m.
Large Conference Room, 1207 Energy Research Facility

Advisor:  Professor Daniel Lathrop

The origins of the Earth’s magnetic field is an ongoing field of study, but is believed to arise from rotating, convecting, and electrically conducting fluid interactions in Earth’s outer core. A brief overview of dynamo theory will be presented, as well as complications that arise in understanding its underlying mechanics. Using a series of experiments of increasing size and increasing power input (now a three-meter diameter system), our group has examined liquid sodium spherical Couette flows to better understand the conditions that bring about Earth’s dynamo. Previous magnetic studies have uncovered magnetic field gain by the Omega effect while being sub-dynamo. After adding baffles to the inner sphere based on the advice of Finke and Tilgner (2014), we see greatly enhanced torques and induced magnetic fields that suggest a possible dynamo. To minimize the external magnetic field for a better constraint on the source of the induced magnetic fields, a canceling electromagnet with 1200 A-turns at the base of the experiment has been designed and implemented. Initial experimental data and analysis with the canceling coil setup show reduction in the dipolar magnetic field component. The current experimental studies work to determine whether the strong induced magnetic fields are caused by interactions with the building/earth’s magnetic field or a possible dynamo, and to verify previous results of exponential growth in the magnetic field. Future plans include analysis of the velocity field using time-domain electromagnetic methods (TDEM) and extracting the governing ODEs of our data using the algorithm SINDy.

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