[Dynamos expérimentales : des modèles aux applications à la géodynamo]
Larmor a proposé en 1919 une explication pour l’origine du champ magnétique du soleil. Cette instabilité dite effet dynamo est considérée comme responsable de la plupart des champs magnétiques des objets astrophysiques dont celui de la Terre. Il a fallu plus de 80 ans après l’explication par Larmor pour que les premières expériences de laboratoire mettent en évidence l’instabilité dynamo. Après une brève présentation des trois expériences qui ont réussi à observer cet effet, je décris ce qu’elles nous ont appris sur les régimes possibles des dynamos des planètes et des étoiles et notamment sur la géodynamo.
Larmor proposed in 1919 an explanation for the origin of the Sun’s magnetic field. This phenomenon, known as the dynamo effect, is considered to be responsible for most of the magnetic fields of astrophysical objects, including that of the Earth. It took over 80 years after Larmor’s explanation for the first laboratory experiments to demonstrate the dynamo instability. After a brief introduction to the three experiments that have managed to observe this effect, I will describe what they have taught us about the possible regimes of dynamos of planets and stars, especially regarding the geodynamo.
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Mots-clés : Magnétohydrodynamique, instabilité dynamo, inversions du champ magnétique terrestre
François Pétrélis 1
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@article{CRPHYS_2024__25_S3_A10_0,
author = {Fran\c{c}ois P\'etr\'elis},
title = {Experimental dynamos: from models to applications to the geodynamo},
journal = {Comptes Rendus. Physique},
publisher = {Acad\'emie des sciences, Paris},
year = {2024},
doi = {10.5802/crphys.205},
language = {en},
note = {Online first},
}
François Pétrélis. Experimental dynamos: from models to applications to the geodynamo. Comptes Rendus. Physique, Online first (2024), pp. 1-17. doi : 10.5802/crphys.205.
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