Award Abstract # 1909055
Development of a roughened inner sphere for the three-meter model of the Earth's core

NSF Org: EAR
Division Of Earth Sciences
Recipient: UNIVERSITY OF MARYLAND, COLLEGE PARK
Initial Amendment Date: June 21, 2019
Latest Amendment Date: July 7, 2022
Award Number: 1909055
Award Instrument: Standard Grant
Program Manager: David Lambert
EAR
 Division Of Earth Sciences
GEO
 Directorate for Geosciences
Start Date: August 1, 2019
End Date: January 31, 2023 (Estimated)
Total Intended Award Amount: $493,431.00
Total Awarded Amount to Date: $591,439.00
Funds Obligated to Date: FY 2019 = $493,431.00
FY 2022 = $98,008.00
History of Investigator:
  • Daniel Lathrop (Principal Investigator)
    lathrop@umd.edu
Recipient Sponsored Research Office: University of Maryland, College Park
3112 LEE BUILDING
COLLEGE PARK
MD  US  20742-5100
(301)405-6269
Sponsor Congressional District: 04
Primary Place of Performance: University of Maryland College Park
MD  US  20742-5103
Primary Place of Performance
Congressional District:
04
Unique Entity Identifier (UEI): NPU8ULVAAS23
Parent UEI: NPU8ULVAAS23
NSF Program(s): Instrumentation & Facilities
Primary Program Source: 01002223DB NSF RESEARCH & RELATED ACTIVIT
01001920DB NSF RESEARCH & RELATED ACTIVIT
Program Reference Code(s):
Program Element Code(s): 158000
Award Agency Code: 4900
Fund Agency Code: 4900
Assistance Listing Number(s): 47.050

ABSTRACT

Our planet's magnetic field directly affects near-Earth radiation during solar storms. This makes it important to understand the process that generates the magnetic field, and also to develop our capacity to predict its changes. This Division of Earth Science Instrumentation and Facilities Program award supports a project which aims to better understand the origin and changes of the Earth's magnetic field. Since these ongoing changes are a result of processes deep in the planet's outer core, it is difficult to do direct studies. The investigators have developed an NSF funded laboratory model of the Earth's outer core: the three-meter liquid sodium experiment. This project will involve a major design modification to the sodium experiment that is needed in order to better mimic the Earth's core, produce model magnetic fields, and enhance our ability to predict magnetic field changes. The project also serves to encourage public appreciation and understanding of geomagnetism through TV and web based documentaries, as well as videos posted on the research group's YouTube channel (www.youtube.com/user/n3umh); to open efforts and activities to non-scientists through frequent tours of the laboratory to a broad range of audiences; and to educate a new generation of scholars in geophysics experiments, including undergraduate mentoring and graduate student training.

The Earth's main magnetic field is central to making our planet a habitable home. During solar maximum, solar storms produce deadly charged particle radiation. The geodynamo magnetic field, along with the Earth's atmosphere, serves to shield us from the worst of these. Nonetheless, solar storms can affect radio communications, the power grid, and spacecraft operations. Thus, we are motivated to understand the origins of the Earth's magnetic field, explore its dynamics, and potentially forecast its behavior. While we know the field changes dramatically over time, including through erratic reversals, there is no reliable predictive science for the weather occurring in the core and no full understanding of the Earth's dynamo generation. An NSF-funded three-meter (3-m) laboratory model of the Earth's core produces induced magnetic fields from rotating turbulence, modeling the dynamics of the Earth's core, and can be used for testing dynamo magnetic field forecasting. One second of experiments mimic approximately 5,000 years of core turbulence (based on the relative magnetic dipole diffusion time scales), allowing observations of detailed magnetic field evolution not possible for the Earth. While previous experiments have yielded important results in hydrodynamics and magnetohydrodynamics since operations began in 2008, the 3-m experiment now requires significant design modifications to increase magnetic field gain. This will be critical for continued studies, including those that directly address questions related to dynamo generation and sustenance. This project will undertake a major modification of the 3-m liquid sodium system that will allow attempting dynamo magnetic field action, and open the parameter space of the system to expand the potential of magnetohydrodynamics experiments. The project also makes direct contributions to the public appreciation and understanding of geomagnetism through TV and web based documentaries and frequent facility tours.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH

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Le Bars, Michael and Barik, Ankit and Burmann, Fabian and Lathrop, Daniel P. and Noir, Jerome and Schaeffer, Nathanael and Triana, Santiago A. "Fluid Dynamics Experiments for Planetary Interiors" Surveys in Geophysics , v.43 , 2021 https://doi.org/10.1007/s10712-021-09681-1 Citation Details
Rojas, Rubén E. and Perevalov, Artur and Zürner, Till and Lathrop, Daniel P. "Experimental study of rough spherical Couette flows: Increasing helicity toward a dynamo state" Physical Review Fluids , v.6 , 2021 https://doi.org/10.1103/PhysRevFluids.6.033801 Citation Details

PROJECT OUTCOMES REPORT

Disclaimer

This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.

Intellectual merit: In this project we successfully accomplished a major modification to our three-meter model of the Earth's outer core. That was done as a multistep hazardous process. After detailed practical and safety planning, including training of first responders on site safety, we draining 12.5 tons of molten sodium into a storage tank. The system was then disassembled and carefully cleaned of residual sodium. The inner core model was modified by welding carefully chosen baffles to roughen the surface to produce more flow helicity. Those changes were suggested by theory to allow greater magnetic field induction. The system was then reassembled, and the 12.5 tons of molten sodium transferred back into the outer sphere. After final assembly and testing, we undertook the first experimental campaigns in the final year of the project. Initial data suggests that the induced magnetic field is greatly enhanced, and that the initial transcients show exponential growth, as suggested by kinematic dynamo theory. The project has set the stage for the next set of experimental campaigns gathering magnetic field data as a model to better understand the geodynamo.

Broader impacts: This project resulted in awarding Ph.D. degrees to Ruben Rojas and Artur Perevalov. As well, we continued to participate in public outreach through documentary filmakers, lab tours, and our laboratory's youtube channel: Lathrop lab.


Last Modified: 06/02/2023
Modified by: Daniel P Lathrop

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