Abstract
A coarse observational/paleomagnetic confirmation is presented for the central hypothesis of paleomagnetism stating the predominance of axial dipole under averaging. The confirmation is based on the averaging time smaller than the full periods for axial dipole and larger than for equatorial one. The dipole-related average geodynamo scales are re-estimated as 18 km from the IGRF’s dipole 1905–2020 variations. That leads to too small convection and geodynamo power estimations based on the known geodynamo-like scaling laws, while obtained here smallest magnetic and average hydrodynamic 7 km scale gives realistic convection power 0.4 TW.
This is a preview of subscription content, log in via an institution to check access.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
References
Aubert J., Gastine T., Fournier A., Spherical convective dynamos in the rapidly rotating asymptotic regime // J. Fluid Mech. V. 813. P. 558-593. 2017.
Braginsky S.I., Roberts P.H. Equations governing convection in the Earth’s core and the geodynamo // Geoph. Astroph. Fluid Dyn. V. 79. P. 1–97. 1995.
Cheng J.S., Aurnou J.M., Tests of diffusion-free scaling behaviors in numerical dynamo datasets // Earth and Planetary Science Letters. V. 436. P. 121–129. 2016.
Christensen U.R. Dynamo Scaling Laws and Applications to the Planets // Space Sci Rev. V. 152, P. 565-590. 2010a.
Christensen U., Aubert J., Hulot G. Conditions for Earth-like geodynamo models // Earth Planet. Sci. Lett. V. 296. P. 487–496. 2010b.
Davidson P.A. An Introduction to Magnetohydrodynamics, Cambridge University Press, 2001.
Gomia H., Ohtaa K., Hirosea K. et al. The high conductivity of iron and thermal evolution of the Earth’s core // Phys. Earth Planet. Int. V. 224. P. 88-103. 2013.
Jackson A., Jonkers A. R. T., Walker M. R. Four centuries of geomagnetic secular variation from historical records // Phil. Trans. R. Soc. Lond. V. A358. P. 957–990. 2000.
Johnson C.L., McFadden P. The Time-Averaged Field and Paleosecular Variation. In: Gerald Schubert (editor-in-chief) Treatise on Geophysics, 2nd edition, V. 5. Oxford: Elsevier; 2015. P. 385-417.
King E.M., Buffett B.A. Flow speeds and length scales in geodynamo models: The role of viscosity // Earth Planet. Sci. Lett. V. 371. P. 156–162. 2013.
Khramov A.N., Goncharov G.I., Komisarova R.A., et al. Paleomagnetologia. L.: Nedra. 1982. 312 pp.
Korte M., Constable C. Improving geomagnetic field reconstructions for 0-3 ka // Phys. Earth Planet. Int. V. 188. P. 247–259. 2011.
Macouin M., Valet J.-P., Besse J. Long-term evolution of the geomagnetic dipole moment // Phys. Earth Planet. Int. V. 147. P. 239–246. 2004.
Ogg J.G., Ogg G., Gradstein F.M. The Concise Geologic Time scale // Cambridge University Press. 2008. 150 pp.
Olson P., Amit H. Changes in earth’s dipole // Naturwissenschaften. V. 93. P. 519-542, 2006.
Pozzo M., Davies C., Gubbins D., Alfe D. Thermal and electrical conductivity of iron at Earth’s core conditions // Nature. V. 485. P. 355–358. 2012.
Rhines P.B. Waves and turbulence on a beta plane // J. Fluid Mech. V. 69. P. 417–433. 1975.
Starchenko S.V. Energetic Scaling of the Geodynamo // Geomagnetism and Aeronomy. V. 53. No 2. P. 243-247. 2013a.
Starchenko S.V. Analytic base of geodynamo-like scaling laws in the planets, geomagnetic periodicities and inversions // Geomagnetism and Aeronomy. V. 54. No 6. P. 694-701. 2014.
Starchenko, S.V., Observational estimate of magnetic field and geodynamo parameters under the surface of the Earth’s core // Geomagnetism and Aeronomy. V. 55. No 5. P. 712-718. 2015.
Starchenko S.V. Hypothetical parameters of planetary dynamos deduced from direct observations, scaling laws, paleomagnetic and isotope reconstructions // Proceedings of the 11th International School and Conference “Problems of Geocosmos” (Oct. 03-07, 2016, St. Petersburg, Russia), edited by V.S. Semenov et al. P. 64-72. 2016.
Starchenko S.V., Jones C.A. Typical velocities and magnetic field strengths in planetary interiors // Icarus. V. 157. P. 426–435. 2002.
Starchenko S.V., Pushkarev Y.D. Magnetohydrodynamic scaling of geodynamo and a planetary protocore concept // Magnetohydrodynamics. V. 49. No. 1. P. 35-42. 2013b.
Ziegler L., Constable C., Johnson C., Tauxe L. PADM2 M: a penalized maximum likelihood model of the 0-2 Ma palaeomagnetic axial dipole moment. Geophys. J. Int. V. 184. P. 1069–1089. 2011.
Acknowledgements
The author is grateful to Valeriy Prohorovich Shcherbakov and Dmitry Dmitrievich Sokoloff for their reasonable criticism resulting in sufficient improving of this paper. The work on it was partly (estimations of magnetic geodynamo parameters) supported by the Russian Foundation for Basic Research with project No 16-05-00507a.
Author information
Authors and Affiliations
Corresponding author
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2019 Springer International Publishing AG, part of Springer Nature
About this paper
Cite this paper
Starchenko, S.V. (2019). Geomagnetic Variations for Axial Dipole Hypothesis and Dynamo Parameters. In: Nurgaliev, D., Shcherbakov, V., Kosterov, A., Spassov, S. (eds) Recent Advances in Rock Magnetism, Environmental Magnetism and Paleomagnetism. Springer Geophysics. Springer, Cham. https://doi.org/10.1007/978-3-319-90437-5_33
Download citation
DOI: https://doi.org/10.1007/978-3-319-90437-5_33
Published:
Publisher Name: Springer, Cham
Print ISBN: 978-3-319-90436-8
Online ISBN: 978-3-319-90437-5
eBook Packages: Earth and Environmental ScienceEarth and Environmental Science (R0)