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Lookup NU author(s): Dr Celine GuervillyORCiD
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
Convection is the main heat transport mechanism in the Earth's liquid core and is thought to power the dynamo that generates the geomagnetic field. Core convection is strongly constrained by rotation while being turbulent. Given the difficulty in modelling these conditions, some key properties of core convection are still debated, including the dominant energy-carrying lengthscale. Different regimes of rapidly-rotating, unmagnetised, turbulent convection exist depending on the importance of viscous and inertial forces in the dynamics, and hence different theoretical predictions for the dominant flow lengthscale have been proposed. Here we study the transition from viscously-dominated to inertia-dominated regimes using numerical simulations in spherical and planar geometries. We find that the cross-over occurs when the inertial lengthscale approximately equals the viscous lengthscale. This suggests that core convection in the absence of magnetic fields is dominated by the inertial scale, which is hundred times larger than the viscous scale.
Author(s): Guervilly C, Dormy E
Publication type: Article
Publication status: Published
Journal: Geophysical Research Letters
Year: 2025
Volume: 52
Issue: 7
Online publication date: 09/04/2025
Acceptance date: 21/02/2025
Date deposited: 27/02/2025
ISSN (print): 0094-8276
ISSN (electronic): 1944-8007
Publisher: Wiley-Blackwell Publishing, Inc.
URL: https://doi.org/10.1029/2024GL111593
DOI: 10.1029/2024GL111593
Data Access Statement: Data sets for this research are available on the Figshare powered Newcastle University research data repository (https://data.ncl.ac.uk) (Guervilly & Dormy, 2025).
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