H. Amit and P. Olson, Helical core flow from geomagnetic secular variation, Physics of the Earth and Planetary Interiors, vol.147, issue.1, pp.1-25, 2004.
DOI : 10.1016/j.pepi.2004.02.006

H. Amit and P. Olson, Time-average and time-dependent parts of core flow, Physics of the Earth and Planetary Interiors, vol.155, issue.1-2, pp.120-139, 2006.
DOI : 10.1016/j.pepi.2005.10.006

H. Amit, P. Olson, and U. Christensen, Tests of core flow imaging methods with numerical dynamos, Geophysical Journal International, vol.168, issue.1, pp.27-39, 2007.
DOI : 10.1111/j.1365-246X.2006.03175.x

J. Aubert, Steady zonal flows in spherical shell dynamos, Journal of Fluid Mechanics, vol.542, issue.-1, pp.53-67, 2005.
DOI : 10.1017/S0022112005006129

J. Aubert, H. Amit, and G. Hulot, Detecting thermal boundary control in surface flows from numerical dynamos, Physics of the Earth and Planetary Interiors, vol.160, issue.2, pp.143-156, 2007.
DOI : 10.1016/j.pepi.2006.11.003

URL : https://hal.archives-ouvertes.fr/hal-00144095

J. Bloxham, Simple models of fluid flow at the core surface derived from geomagnetic field models, Geophysical Journal International, vol.99, issue.1, pp.173-182, 1989.
DOI : 10.1111/j.1365-246X.1989.tb02022.x

J. Bloxham and D. Gubbins, Thermal core??? mantle interactions, Nature, vol.16, issue.6104, pp.511-513, 1987.
DOI : 10.1038/311709a0

J. Bloxham and A. Jackson, Fluid flow near the surface of Earth's outer core, Reviews of Geophysics, vol.94, issue.2, pp.97-120, 1991.
DOI : 10.1029/90RG02470

C. Bouligand, G. Hulot, A. Khokhlov, and G. Glatzmaier, Statistical paleomagnetic field modeling and dynamo numerical simulation, Geophys, J. Int, vol.161, pp.603-626, 2005.

J. Carlut and V. Courtillot, How complex is the time-averaged geomagnetic field over the past 5 Myr?, Geophys, J. Int, vol.134, pp.527-544, 1998.

U. Christensen and P. Olson, Secular variation in numerical geodynamo models with lateral variations of boundary heat flow, Physics of the Earth and Planetary Interiors, vol.138, issue.1, pp.39-54, 2003.
DOI : 10.1016/S0031-9201(03)00064-5

A. Chulliat and G. Hulot, Local computation of the geostrophic pressure at the top of the core, Physics of the Earth and Planetary Interiors, vol.117, issue.1-4, pp.309-328, 2000.
DOI : 10.1016/S0031-9201(99)00104-1

C. Constable, C. Johnson, and S. Lund, Global geomagnetic field models for the past 3000 years: transient or permanent flux lobes?, Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, vol.358, issue.1768, pp.991-1008, 2000.
DOI : 10.1098/rsta.2000.0570

A. M. Dziewonsky and D. L. Anderson, Preliminary reference Earth model, Physics of the Earth and Planetary Interiors, vol.25, issue.4, pp.297-356, 1981.
DOI : 10.1016/0031-9201(81)90046-7

C. Eymin and G. Hulot, On core surface flows inferred from satellite magnetic data, Physics of the Earth and Planetary Interiors, vol.152, issue.3, pp.200-220, 2005.
DOI : 10.1016/j.pepi.2005.06.009

URL : https://hal.archives-ouvertes.fr/insu-00372754

A. M. Forte and J. X. Mitrovica, Deep-mantle high-viscosity flow and thermochemical structure inferred from seismic and geodynamic data

S. J. Gibbons and D. Gubbins, Convection in the earths core driven by lateral variations in the core-mantle boundary heat flux, Geophys, J. Int, vol.142, pp.631-642, 2000.

G. Glatzmaier, R. Coe, L. Hongre, and P. Roberts, The role of the earth's mantle in controlling the frequency of geomagnetic reversals, Nature, vol.401, issue.6756, pp.885-890, 1999.
DOI : 10.1038/44776

D. Gubbins, Thermal core-mantle interactions: theory and observations, in Earth's Core: dynamics, structure and rotation, 2003.

D. Gubbins and P. Kelly, Persistent patterns in the geomagnetic field over the past 2.5 Myr, Nature, vol.365, issue.6449, pp.829-832, 1993.
DOI : 10.1038/365829a0

R. Holme, Electromagnetic core-mantle coupling-I. Explaining decadal changes in the length of day, Geophysical Journal International, vol.132, issue.1, pp.167-180, 1998.
DOI : 10.1046/j.1365-246x.1998.00424.x

R. Holme, Large-scale Flow in the Core, Treatise on Geophysics, 2007.

L. Hongre, G. Hulot, and A. Khokhlov, An analysis of the geomagnetic field over the past 2000 years, Physics of the Earth and Planetary Interiors, vol.106, issue.3-4, pp.311-335, 1998.
DOI : 10.1016/S0031-9201(97)00115-5

G. Hulot and J. Lemouël, A statistical approach to the Earth's main magnetic field, Physics of the Earth and Planetary Interiors, vol.82, issue.3-4, pp.167-183, 1994.
DOI : 10.1016/0031-9201(94)90070-1

G. Hulot and C. Bouligand, Statistical palaeomagnetic field modelling and symmetry considerations, Geophysical Journal International, vol.161, issue.3, pp.591-602, 2005.
DOI : 10.1111/j.1365-246X.2005.02612.x

URL : https://hal.archives-ouvertes.fr/insu-01404634

G. Hulot, C. Eymin, B. Langlais, M. Mandea, and N. Olsen, Small-scale structure of the geodynamo inferred from Oersted and Magsat satellite data, Nature, vol.416, issue.6881, pp.620-623, 2002.
DOI : 10.1038/416620a

A. Jackson, J. Bloxham, and D. Gubbins, in Dynamics of Earth's deep interior and Earth rotation, 1993.

A. Jackson, A. R. Jonkers, and M. R. Walker, Four centuries of geomagnetic secular variation from historical records, Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, vol.358, issue.1768, pp.957-990, 2000.
DOI : 10.1098/rsta.2000.0569

C. Johnson and C. Constable, The time-averaged geomagnetic field as recorded by lava flows over the past 5 Myr, Geophysical Journal International, vol.122, issue.2, pp.489-519, 1995.
DOI : 10.1111/j.1365-246X.1995.tb07010.x

A. Khokhlov, G. Hulot, and C. Bouligand, Testing statistical paleomagnetic field models against directional data affected by measurement errors , Geophys, J. Int, vol.167, pp.635-648, 2006.

M. Korte, A. Genevey, C. Constable, U. Frank, and E. Schnepp, Continuous geomagnetic field models for the past 7 millenia: 1. A new global data compilation, Geochem. Geophys. Geosyst, vol.6, pp.10-1029, 2005.

C. Kutzner and U. Christensen, From stable dipolar towards reversing numerical dynamos, Physics of the Earth and Planetary Interiors, vol.131, issue.1, pp.29-45, 2002.
DOI : 10.1016/S0031-9201(02)00016-X

L. Huy, M. , J. Lemouël, and A. Pais, Time evolution of the fluid flow at the top of the core. Geomagnetic jerks, Earth Planets Space, pp.163-173, 2000.

M. Mcelhinny, P. Mcfadden, and R. Merrill, The time-averaged paleomagnetic field 0-5 Ma, Journal of Geophysical Research: Solid Earth, vol.39, issue.B11, pp.7-25027, 1996.
DOI : 10.1029/96JB01911

M. Murakami, K. Hirose, K. Kawamura, N. Sata, and Y. Ohishi, Post-Perovskite Phase Transition in MgSiO3, Science, vol.304, issue.5672, pp.855-858, 2004.
DOI : 10.1126/science.1095932

P. Olson and U. Christensen, The time-averaged magnetic field in numerical dynamos with non-uniform boundary heat flow, Geophysical Journal International, vol.151, issue.3, pp.809-823, 2002.
DOI : 10.1046/j.1365-246X.2002.01818.x

P. Olson, U. R. Christensen, and G. A. Glatzmaier, Numerical modeling of the geodynamo: Mechanisms of field generation and equilibration, Journal of Geophysical Research: Solid Earth, vol.24, issue.B5, pp.10383-10404, 1999.
DOI : 10.1029/1999JB900013

P. Olson and G. A. Glatzmaier, Magnetoconvection and Thermal Coupling of the Earth's Core and Mantle, Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, vol.354, issue.1711, pp.1413-1424, 1996.
DOI : 10.1098/rsta.1996.0055

P. Olson, I. Sumita, and J. Aurnou, Diffusive magnetic images of upwelling patterns in the core, Journal of Geophysical Research: Solid Earth, vol.86, issue.B12, p.2348, 2002.
DOI : 10.1029/2001JB000384

A. Pais and G. Hulot, Length of day decade variations, torsional oscillations and inner core superrotation: evidence from recovered core surface zonal flows, Physics of the Earth and Planetary Interiors, vol.118, issue.3-4, pp.291-316, 2000.
DOI : 10.1016/S0031-9201(99)00161-2

J. Pedlosky, Geophysical Fluid Dynamics, 1987.
DOI : 10.1007/978-1-4612-4650-3

J. Poirier, Introduction to the Physics of the Earth's Interior, 312 pp, 2000.

S. Rau, U. Christensen, A. Jackson, and J. Wicht, Core flow inversion tested with numerical dynamo models, Geophys, J. Int, vol.141, pp.485-497, 2000.
DOI : 10.1046/j.1365-246x.2000.00097.x

URL : http://gji.oxfordjournals.org/cgi/content/short/141/2/485

J. Trampert, F. Deschamps, J. Resovsky, and D. Yuen, Probabilistic Tomography Maps Chemical Heterogeneities Throughout the Lower Mantle, Science, vol.306, issue.5697, pp.853-856, 2004.
DOI : 10.1126/science.1101996

D. A. Yuen, O. Cadek, A. Chopelas, and C. Mtyska, Geophysical inferences of thermal-chemical structures in the lower mantle, Geophysical Research Letters, vol.355, issue.3, pp.899-902, 1993.
DOI : 10.1029/93GL00867

H. Amit, e-mail: hagay@ipgp.jussieu.fr