Core-mantle relative motion and coupling

Vanyo, James P.

doi:10.1111/j.1365-246x.2004.02296.x

Cited by 13 publications

(11 citation statements)

References 25 publications

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“…The power required to drive the geodynamo also appears to be smaller than previously estimated (Christensen and Tilgner, 2004). Experiments contributed in showing that the flow geometry generated in a rotating and precessing spheroidal envelope filled with water, is similar to the flow in the outer core inferred from geomagnetic secular variation (Vanyo, 2004). Finally, numerical reconstructions of the dynamo effect of a precessiondriven flow in a spherical container (Tilgner, 2005) showed that i) laminar and unstable flows maintain the dynamo; ii) for low ratios of viscosity/geostrophic forces (i.e.…”

Section: Introductionmentioning

confidence: 76%

Paleoclimatic context of geomagnetic dipole lows and excursions in the Brunhes, clue for an orbital influence on the geodynamo?

Thouveny

Bourlès

Saracco

et al. 2008

Earth and Planetary Science Letters

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International audienceThe hypothesis of an influence of the astronomical precession on the geodynamo energy budget was recently reappraised by theoreticians. Paleomagnetic indications of such an influence remain controversial because reconstructions of paleointensity variations from sediments are suspected to be contaminated by lithological, paleoclimatically induced influences. Three sets of complementary indicators are however available: 1) records of the direction of magnetization in sediments, 2) records of magnetic anomalies of the deep sea floor basalts and 3) records of production variations of cosmogenic isotopes from sediment and ice cores. These records confirm the genuine geomagnetic origin of paleointensity lows and their narrow link with excursions or short reversals recorded in various materials and often dated by radiometric methods. The analysis of these time series and their comparison with δ18O records of the paleoclimate suggest that such globally recorded geomagnetic dipole lows have preferentially occurred in the context of interglacial or transitional paleoclimates at the time of low or decreasing obliquity. The dominant periods, extracted with the complex continuous wavelet transform technique, range from 40 to 125 ka, further suggesting a link with orbital parameters. These results encourage future efforts of research to improve the precision, the resolution and the dating of the time series of geomagnetic dipole low, in order to better decipher orbital signatures and understand their origin. An important implication of this topic is that the next geomagnetic dipole low should be related with the present interglacial

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Section: Introductionmentioning

confidence: 76%

Paleoclimatic context of geomagnetic dipole lows and excursions in the Brunhes, clue for an orbital influence on the geodynamo?

Thouveny

Bourlès

Saracco

et al. 2008

Earth and Planetary Science Letters

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“…The most ambitious project within the framework of DRESDYN is a large scale precession dynamo experiment. Precession has been discussed since long as an, at least complementary, energy source of the geodynamo [7,8,9,10,11,12]. This idea is supported by paleomagnetic measurements that have revealed a modulation of the geomagnetic field intensity by the 100 kyr Milanković cycle of the Earth's orbit eccentricity and by the corresponding 41 kyr cycle of the Earth's axis obliquity [13].…”

Section: Precession Driven Dynamomentioning

confidence: 99%

DRESDYN -- a new facility for MHD experiments with liquid sodium

Stefani¹,

Eckert²,

Gerbeth³

et al. 2012

MHD

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The DREsden Sodium facility for DYNamo and thermohydraulic studies (DRESDYN) is intended as a platform both for large scale experiments related to geo-and astrophysics as well as for experiments related to thermohydraulic and safety aspects of liquid metal batteries and liquid metal fast reactors. The most ambitious projects in the framework of DRESDYN are a homogeneous hydromagnetic dynamo driven solely by precession and a large Taylor-Couette type experiment for the combined investigation of the magnetorotational instability and the Tayler instability. In this paper we give a short summary about the ongoing preparations and delineate the next steps for the realization of DRESDYN.

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“…Dynamo action of precession-driven flows is, unfortunately, a largely unsolved problem, despite a number of attempts to apply it to the dynamo of the Earth and other cosmic bodies [55,56,57,58,59]. The DRESDYN precession dynamo experiment was partly motivated by the optimistic numerical estimations obtained by Nore [49,37] for the cylinder, and Krauze [51] for a cube; both pointed consistently to a critical Rm on the order of 700.…”

Section: Precession-driven Dynamos In Cylinders and Cubesmentioning

confidence: 99%

Magnetic field dynamos and magnetically triggered flow instabilities

Stefani

Albrecht

Arlt

et al. 2017

IOP Conf. Ser.: Mater. Sci. Eng.

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Magnetic fields of planets, stars and galaxies are generated by self-excitation in moving electrically conducting fluids. Once produced, magnetic fields can play an active role in cosmic structure formation by destabilizing rotational flows that would be otherwise hydrodynamically stable. For a long time, both hydromagnetic dynamo action as well as magnetically triggered flow instabilities had been the subject of purely theoretical research. Meanwhile, however, the dynamo effect has been observed in large-scale liquid sodium experiments in Riga, Karlsruhe and Cadarache. In this paper, we summarize the results of liquid metal experiments devoted to the dynamo effect and various magnetic instabilities such as the helical and the azimuthal magnetorotational instability and the Tayler instability. We discuss in detail our plans for a precession-driven dynamo experiment and a large-scale Tayler-Couette experiment using liquid sodium, and on the prospects to observe magnetically triggered instabilities of flows with positive shear.

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Core-mantle relative motion and coupling

Cited by 13 publications

References 25 publications

Paleoclimatic context of geomagnetic dipole lows and excursions in the Brunhes, clue for an orbital influence on the geodynamo?

Paleoclimatic context of geomagnetic dipole lows and excursions in the Brunhes, clue for an orbital influence on the geodynamo?

DRESDYN -- a new facility for MHD experiments with liquid sodium

Magnetic field dynamos and magnetically triggered flow instabilities

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