Abstract
Our understanding of the dynamics of the Earth’s core can be advanced by a combination of observation, experiments, and simulations. A crucial aspect of the core is the interplay between the flow of the conducting liquid and the magnetic field this flow sustains via dynamo action. This non-linear interaction, and the presence of turbulence in the flow, precludes direct numerical simulation of the system with realistic turbulence. Thus, in addition to simulations and observations (both seismological and geomagnetic), experiments can contribute insight into the core dynamics. Liquid sodium laboratory experiments can serve as models of the Earth’s core with the key ingredients of conducting fluid, turbulent flow, and overall rotation, and can also approximate the geometry of the core. By accessing regions of parameter space inaccessible to numerical studies, experiments can benchmark simulations and reveal phenomena relevant to the Earth’s core and other planetary cores. This review focuses on the particular contribution of liquid sodium spherical Couette devices to this subject matter.
Highlights
Large-scale magnetic fields are common in the universe and are found in planets, stars, accretion disks, and galaxies
Many of these fields are thought to be the result of self-sustaining dynamo action, whereby motions of a conductive fluid in the presence of a magnetic field give rise to induced currents that in turn generate magnetic fields that reinforce the original field (Larmor 1919; see e.g., Rüdiger and Hollerbach 2004)
Starting from an arbitrarily small field, the flow of a conductive fluid, driven by some energy source, can result in a persistent large-scale magnetic field that can show a variety of dynamical changes including polarity reversals
Summary
Large-scale magnetic fields are common in the universe and are found in planets, stars, accretion disks, and galaxies Many of these fields are thought to be the result of self-sustaining dynamo action, whereby motions of a conductive fluid in the presence of a magnetic field give rise to induced currents that in turn generate magnetic fields that reinforce the original field (Larmor 1919; see e.g., Rüdiger and Hollerbach 2004). Most stars generally have magnetic fields that are thought to arise via dynamo The prevalence of such large-scale fields implies that this mechanism of dynamo action is robust, generally having three ingredients: a large volume of conductive fluid, an energy source to drive the dynamo, and overall rotation to help organize the flow (see, e.g., Olson 2013). Given that the conservation of angular momentum results in most stars and planetary bodies having a significant amount of overall rotation, rotational effects will often be present even in dynamos
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
