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Simple Planetary Convection and Magnetism Estimations via Scaling and Observations

  • S. V. StarchenkoEmail author
Conference paper
Part of the Springer Proceedings in Earth and Environmental Sciences book series (SPEES)

Abstract

Scaling laws describing planetary convection are considered with the purpose to obtain a simple formulation of equations governing turbulent convection in the critical regime close to the convection onset. This justifies, in a certain way, the available numerical models of the planetary convection and MHD dynamos that are too simple and nevertheless successful. Such dynamos are considered here for known terrestrial planets and moons. The arithmetic mean magnetic field (AMF) in the dynamo region is ~1 mT, and AMF vector follows closely the rotation axis for the Earth, Jupiter and Saturn. The Uranus and Neptune have large inclinations and AMF ~0.1 mT. Similar value is believed to hold for Ganymede. The smallest AMF ~0.01 mT is in Mercury. The geodynamo root-mean-squared field (RMF) to AMF ratio is estimated from 10 to 100 from scaling laws. The same order values may hold for Jupiter and Saturn while other planets might have smaller ratios. RMF/AMF ratio can also be viewed as a simple measure of the internal planetary magnetic field intermittency.

Keywords

Planetary magnetism and convection Turbulent transport Scaling laws Observed planetary magnetism Geodynamo 

Notes

Acknowledgements

I am very grateful to the anonymous referee who not only gave me very valuable remarks to improve this work, but also shared with me valuable references and a few pieces of text I enjoyed to use. This work was basically supported by IZMIRAN budget. Partial supports in planetary magnetism were by 28th program of the Presidium of Russian Academy of Sciences. My special thanks to the editor of this volume Dr. Andrei Kosterov for his efforts to improve my text.

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© Springer Nature Switzerland AG 2020

Authors and Affiliations

  1. 1.Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation, Russian Academy of Sciences (IZMIRAN)MoscowRussia

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