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Volume 59 Supplement 7

Special Issue: Perspectives of Geomagnetism: Geodynamo, Paleomagnetism, and Rock magnetism—Tribute to Prof. Masaru Kono

A numerical study on magnetic polarity transition in an MHD dynamo model

Earth, Planets and Space volume 59, pages 665–673 (2007)Cite this article

Abstract

Magnetic polarity transitions in a Takahashi-Matsushima-Honkura dynamo model are analyzed. Distinctive differences in behavior of the axisymmetric poloidal magnetic field are found among a polarity reversal and excursions, including short polarity events. At the beginning of magnetic polarity transitions, the magnetic field with the reversed polarity is generated by anti-cyclonic convection columns deep within the outer core. In the case of excursion, it is soon advected by the radial flow toward a shallow interior of the core, and the transition can be detected at the core surface. However, the same process retrieves the original polarity from the deep interior, and the reversed field eventually vanishes. In the case of polarity reversal, on the other hand, the reversed polarity field is persistently generated deep within the core. It is then advected toward a shallow interior of the core, while the generation process of the reversed field occurs successively. The reversed polarity field near the core surface is collected by the downwelling flow associated with convection columns, as is the case for the original polarity field. The polarity reversal is completed by the advection process, the duration of which is consistent with the flow speed in the core.

References

  • Bouligand, C., G. Hulot, A. Khokhlov, and G. A. Glatzmaier, Statistical palaeomagnetic field modelling and dynamo numerical simulation, Geophys. J. Int., 161, 603–626, 2005.

    Article  Google Scholar 

  • Brown, L. L., B. S. Singer, J. C. Pickens, and B. R. Jicha, Paleomagnetic directions and 40Ar/39Ar ages from the Tatara-San Pedro volcanic complex, Chilean Andes: Lava record of a Matuyama-Brunhes precursor?, J. Geophys. Res., 109, B12101, doi:10.1029/2004JB003007, 2004.

    Article  Google Scholar 

  • Christensen, U. R. and J. Aubert, Scaling properties of convection-driven dynamos in rotating spherical shells and application to planetary magnetic fields, Geophys. J. Int., 166, 97–114, 2006.

    Article  Google Scholar 

  • Christensen, U. R., P. Olson, and G. A. Glatzmaier, Numerical modelling of the geodynamo: A systematic parameter study, Geophys. J. Int., 138, 393–409, 1999.

    Article  Google Scholar 

  • Clement, B. M., Dependence of the duration of geomagnetic polarity reversals on site latitude, Nature, 428, 637–640, 2004.

    Article  Google Scholar 

  • Coe, R., L. Hongre, and G. A. Glatzmaier, An examination of simulated geomagnetic reversals from a palaeomagnetic perspective, Philos. Trans. R. Soc. Lond. A, 358, 1141–1170, 2000.

    Article  Google Scholar 

  • Glatzmaier, G. A. and P. H. Roberts, A three-dimensional self-consistent computer simulation of a geomagnetic field reversal, Nature, 377, 203–209, 1995.

    Article  Google Scholar 

  • Gubbins, D., The distinction between geomagnetic excursions and reversals, Geophys. J. Int., 137, F1–F4, 1999.

    Article  Google Scholar 

  • Gubbins, D. and K. Zhang, Symmetry properties of the dynamo equations for palaeomagnetism and geomagnetism, Phys. Earth Planet. Inter., 75, 225–241, 1993.

    Article  Google Scholar 

  • Guillou, H., B. S. Singer, C. Laj, C. Kissel, S. Scaillet, and B. R. Jicha, On the age of the Laschamp geomagnetic excursion, Earth Planet. Sci. Lett, 227, 331–343, 2004.

    Article  Google Scholar 

  • Kageyama, A., T. Sato, and the Complexity Simulation Group, Computer simulation of a magnetohydrodynamic dynamo II, Phys. Plasmas, 2, 1421–1431, 1995.

    Article  Google Scholar 

  • Kono, M. and P. H. Roberts, Recent geodynamo simulations and observations of the geomagnetic field, Rev. Geophys., 40, 1013, doi:10. 1029/2000RG000102, 2002.

    Article  Google Scholar 

  • Kutzner, C. and U. R. Christensen, From stable dipolar towards reversing numerical dynamos, Phys. Earth Planet. Inter., 131, 29–45, 2002.

    Article  Google Scholar 

  • Kutzner, C. and U. R. Christensen, Simulated geomagnetic reversals and preferred virtual geomagnetic pole paths, Geophys. J. Int., 157, 1105–1118, 2004.

    Article  Google Scholar 

  • Li, J., T. Sato, and A. Kageyama, Repeated and sudden reversals of the dipole field generated by a spherical dynamo action, Science, 295, 1887–1890, 2002.

    Article  Google Scholar 

  • McMillan, D. G., C. G. Constable, R. L. Parker, and G. A. Glatzmaier, A statistical analysis of magnetic fields from some geodynamo simulations, Geochem. Geophys. Geosyst., 2, doi:10.1029/2000GC000130, 2001.

  • Merrill, R., M. McElhinny, and P. McFadden, The Magnetic Field of the Earth, Academic Press, San Diego, 1

    Google Scholar 

  • Mochizuki, N., H. Tsunakawa, H. Shibuya, T. Tagami, A. Ozawa, J. Cassidy, and I. E. M. Smith, K-Ar ages of the Auckland geomagnetic excursions, Earth Planets Space, 56, 283–288, 2004.

    Article  Google Scholar 

  • Mochizuki, N., H. Tsunakawa, H. Shibuya, J. Cassidy, and I. E. M. Smith, Palaeointensities of the Auckland geomagnetic excursions by the LTD-DHT Shaw method, Phys. Earth Planet. Inter., 154, 168–179, 2006.

    Article  Google Scholar 

  • Mochizuki, N., H. Tsunakawa, H. Shibuya, T. Tagami, A. Ozawa, and I. E. M. Smith, Further K-Ar dating and paleomagnetic study of the Auckland geomagnetic excursions, Earth Planets Space, 59, this issue, 755–761, 2007.

    Article  Google Scholar 

  • Oda, H., M. J. Dekkers, C. G. Langereis, L. Lourens, and D. Heslop, A paleomagnetic record of the last 640 kyr from an eastern Mediterranean piston core and a review of geomagnetic excursions in the Brunhes, EOS Trans. AGU, 95, GP41B-08 (Abstract), 2004.

  • Olson, P. and U. R. Christensen, Dipole moment scaling for convection-driven planetary dynamos, Earth Planet. Sci. Lett, 250, 561–571, 2006.

    Article  Google Scholar 

  • Olson, P., U. R. Christensen, and G. A. Glatzmaier, Numerical modeling of the geodynamo: Mechanisms of field generation and equilibration, J. Geophys. Res., 104, 10383–10404, 1999.

    Article  Google Scholar 

  • Sarson, G. R. and C. A. Jones, A convection driven geodynamo reversal model, Phys. Earth Planet. Inter., 111, 3–20, 1999.

    Article  Google Scholar 

  • Singer, B. S., M. K. Relle, K. A. Hoffman, A. Battle, C. Laj, H. Guillou, and J. C. Carracedo, Ar/Ar ages from transitionally magnetized lavas on La Palma, Canary Islands, and the geomagnetic instability timescale, J. Geophys. Res., 107, 2307, doi:10.1029/2001JB001613, 2002.

    Article  Google Scholar 

  • Takahashi, F. and M. Matsushima, Dynamo action in a rotating spherical shell at high Rayleigh numbers, Phys. Fluids, 17, 076601, 2005.

    Article  Google Scholar 

  • Takahashi, F., J. S. Katayama, M. Matsushima, and Y. Honkura, Effects of boundary layers on magnetic field behavior in an MHD dynamo model, Phys. Earth Planet. Inter., 128, 149–161, 2001.

    Article  Google Scholar 

  • Takahashi, F., M. Matsushima, and Y. Honkura, Dynamo action and its temporal variation inside the tangent cylinder in MHD dynamo simulations, Phys. Earth Planet. Inter., 140, 53–71, 2003.

    Article  Google Scholar 

  • Takahashi, F., M. Matsushima, and Y. Honkura, Simulations of a quasiTaylor state geomagnetic field including polarity reversals on the Earth Simulator, Science, 309, 459–461, 2005.

    Article  Google Scholar 

  • Takahashi, F., M. Matsushima, and Y. Honkura, Scale variability in convection-driven MHD dynamos at low Ekman number, Geophys. J. Int., 2007 (submitted).

    Google Scholar 

  • Wicht, J., Inner-core conductivity in numerical dynamo simulations, Phys. Earth Planet. Inter., 132, 281–302, 2002.

    Article  Google Scholar 

  • Wicht, J., Palaeomagnetic interpretation of dynamo simulations, Geophys. J. Int., 162, 371–380, 2005.

    Article  Google Scholar 

  • Wicht, J. and P. Olson, A detailed study of the polarity reversal mechanism in a numerical dynamo model, Geochem. Geophys. Geosyst., 5, Q03H10, doi:10.1029/2003GC000602, 2004.

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Authors and Affiliations

  1. Department of Earth and Planetary Sciences, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo, 152-8551, Japan

    Futoshi Takahashi, Masaki Matsushima & Yoshimori Honkura

Authors
  1. Futoshi Takahashi
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  2. Masaki Matsushima
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  3. Yoshimori Honkura
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Correspondence to Futoshi Takahashi.

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Takahashi, F., Matsushima, M. & Honkura, Y. A numerical study on magnetic polarity transition in an MHD dynamo model. Earth Planet Sp 59, 665–673 (2007). https://doi.org/10.1186/BF03352729

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