Geomagnetic field and the growth of the Earth's inner core: Past, present and future

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985530%3A_____%2F25%3A00641702" target="_blank" >RIV/67985530:_____/25:00641702 - isvavai.cz</a>

Result on the web

<a href="https://www.sciencedirect.com/science/article/pii/S0031920125001542?via%3Dihub" target="_blank" >https://www.sciencedirect.com/science/article/pii/S0031920125001542?via%3Dihub</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.pepi.2025.107460" target="_blank" >10.1016/j.pepi.2025.107460</a>

Result language

angličtina

Original language name

Geomagnetic field and the growth of the Earth's inner core: Past, present and future

Original language description

Changes in the geomagnetic field corresponding to the Earth's inner core growth are numerically investigated. The Geodynamo is driven by thermochemical convection in the Earth's outer core, with the codensity gradient serving as the primary driving force. Simulations begin with a small inner core ('Past'), which progressively enlarges until reaching a stage where the inner core becomes dominant ('Future'). During the 'Past' stage, the Geodynamo model generates a multipolar geomagnetic field, which gradually transitions into a predominantly dipolar field as the inner core grows. These transitions are also accompanied by shifts between weak-field and strong-field dynamos and vice versa. The ratio of magnetic to kinetic energy emerges as a more reliable parameter for controlling the transition from multipolar to dipolar dynamos. The dipole component for a small inner core proves unstable, with frequent polarity reversals. As the inner core grows, the frequency of these reversals decreases until the 'Present' case, where polarity reversals cease entirely. It is important to note that during the 'Past', fluctuations in dipole polarity are observed even in a dipole-dominated magnetic field. In the 'Future' stage, representing a potential scenario for the Earth's geomagnetic field, the hydromagnetic dynamo produces a dipole-dominated magnetic field without polarity reversals. However, if the Earth's liquid outer core becomes exceedingly small, convection diminishes, causing the Geodynamo to fail. This leads to a slow decay of the magnetic field due to magnetic diffusion. During the 'Future' stage, the emergence of subcritical dynamos is observed. It is important to note that the results of the present analysis are more strongly influenced by the supercriticality of the flow than by the inner core size, as the latter is determined by the selected solution parameters.

Czech name

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Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

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OECD FORD branch

10508 - Physical geography

Project

—

Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2025

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Physics of the Earth and Planetary Interiors

ISSN

0031-9201

e-ISSN

1872-7395

Volume of the periodical

368

Issue of the periodical within the volume

Nov.

Country of publishing house

NL - THE KINGDOM OF THE NETHERLANDS

Number of pages

15

Pages from-to

107460

UT code for WoS article

001608567700001

EID of the result in the Scopus database

2-s2.0-105020016337