Results 31 to 40 of about 3,588 (211)

Asymmetric Dipole Trends in Geodynamo Models and the Paleomagnetic Field

Geochemistry, Geophysics, Geosystems, 2023
Temporal trends in the paleomagnetic dipole moment exhibit the property of positive skewness. On average, positive trends are larger and occur less frequently than negative trends over timescales of several tens of kyr.
B. A. Buffett
doaj   +1 more source

The Cretaceous Normal Superchron: A Mini-Review of Its Discovery, Short Reversal Events, Paleointensity, Paleosecular Variations, Paleoenvironment, Volcanism, and Mechanism

Frontiers in Earth Science, 2022
The Cretaceous Normal Superchron (CNS) was first defined in the 1960s to explain the Cretaceous Quiet Zone in marine magnetic anomaly profiles, which includes no or fewer geomagnetic reversals.
Yutaka Yoshimura
doaj   +1 more source

Paleomagnetic Biases Inferred From Numerical Dynamos and the Search for Geodynamo Evolution

Frontiers in Earth Science, 2018
The paleomagnetic record is central to our understanding of the history of the Earth. The orientation and intensity of magnetic minerals preserved in ancient rocks indicate the geodynamo has been alive since at least the Archean and possibly the Hadean ...
Peter E. Driscoll, Cian Wilson
doaj   +1 more source

Geodynamo and mantle convection simulations on the Earth Simulator using the Yin-Yang grid

, 2005
We have developed finite difference codes based on the Yin-Yang grid for the geodynamo simulation and the mantle convection simulation. The Yin-Yang grid is a kind of spherical overset grid that is composed of two identical component grids. The intrinsic
Akira Kageyama, Bercovici B, Hernlund J W, Kageyama A, Komine K, Masaki Yoshida, McKenzie D P, Phillips N A, Phillips N A, Steger J L, Steger J L, Takahashi K, Takahashi K, Turcotte D L, Wesseling P   +14 more
core   +1 more source

Variational data assimilation for the initial-value dynamo problem [PDF]

, 2011
The secular variation of the geomagnetic field as observed at the Earth's surface results from the complex magnetohydrodynamics taking place in the fluid core of the Earth.
Andrew Jackson, B. P. Jones, D. Gubbins, G. Backus, G. Evensen, G. W. Hanson, H. K. Moffatt, J. Larmor, J. Nocedal, J. P. Aubin, J. P. Boyd, K. Ito, Kuan Li, M. Kono, O. Talagrand, Philip W. Livermore, R. D. Gibson, R. L. Parker, R. Reed, T. H. Cormen, T. Namikawa, W. Kuang, W. Kuang   +22 more
core   +1 more source

Nonlinearity in a dynamo [PDF]

, 2009
Using a rotating flat layer heated from below as an example, we consider effects which lead to stabilizing an exponentially growing magnetic field in magnetostrophic convection in transition from the kinematic dynamo to the full non-linear dynamo.
Cattaneo F, Chandrasekhar S, Hughes D, Kazantsev AP, Kleeorin N, M. Reshetnyak, Moffatt HK, P. Hejda, Rose HA, Zeldovich YaB   +9 more
core   +1 more source

Mode analysis of numerical geodynamo models

, 2011
It has been suggested in Hoyng (2009) that dynamo action can be analysed by expansion of the magnetic field into dynamo modes and statistical evaluation of the mode coefficients.
Aubert, Brandenburg, Busse, Christensen, Christensen, Christensen, Christensen, Christensen, Courvoisier, D. Schmitt, Dormy, Driscoll, Gissinger, Glatzmaier, Glatzmaier, Holme, Hoyng, Hubbard, Hughes, Hulot, Kageyama, Kaiser, Kuang, Kutzner, Le Mouël, Lhuillier, M. Schrinner, Olson, P. Hoyng, Pétrélis, Rheinhardt, Roberts, Sarson, Schrinner, Schrinner, Schrinner, Schrinner, Schrinner   +37 more
core   +2 more sources

On the Precession Driven Geodynamo [PDF]

Izvestiya, Physics of the Solid Earth, 2006
Formation of flow structures in the Earth’s liquid core enclosed in a precessing and rotating shell (mantle) is examined within the hydrodynamic approach. The kinematics and energetics of the motions in the Earth’s core initiated by precession allow one to regard these motions as a possible geodynamo mechanism at an early evolutionary stage of the ...
openaire   +1 more source

Geodynamo alpha-effect derived from box simulations of rotating magnetoconvection

, 2004
The equations for fully compressible rotating magnetoconvection are numerically solved in a Cartesian box assuming conditions roughly suitable for the geodynamo.
A. Giesecke, Buffet, Busse, Chandrasekhar, Christensen, G. Rüdiger, Hollerbach, Hollerbach, Kitchatinov, Krause, Olson, Ossendrijver, Ossendrijver, Roberts, Rüdiger, Schmitt, Soward, Stefani, Stefani, U. Ziegler, Ziegler, Ziegler, Ziegler, Ziegler   +23 more
core   +1 more source

Solar Magnetic Field Reversals and the Role of Dynamo Families [PDF]

, 2012
The variable magnetic field of the solar photosphere exhibits periodic reversals as a result of dynamo activity occurring within the solar interior. We decompose the surface field as observed by both the Wilcox Solar Observatory and the Michelson Doppler
A. S. Brun, Abramowitz, Alexakis, Basu, Browning, Brun, Böhm-Vitense, Cattaneo, Charbonneau, Choudhuri, Dikpati, Dikpati, Dikpati, Guckenheimer, Hoeksema, J. T. Hoeksema, Karak, Knobloch, M. L. DeRosa, Melbourne, Moffatt, Pétrélis, Racine, Reiners, Reiners, Ribes, Roberts, Ruzmaikin, Saar, Schrijver, Stenflo, Strugarek, Tobias, Valet, Yeates   +34 more
core   +3 more sources