A Solenoid

Melting Earth's core in the laboratory by using laser-heating technique in the diamond-anvil cell.

Yingwei Fei Science 2013;340:442-443Published by AAAS

Low-Pressure Iron Phase Diagram

Body-centered cubic (α-iron and δ-iron) Face-centered cubic (γ-iron) Hexagonal close-packed (ε-iron)

Fig. 2 Pressure (PKCl)–temperature conditions at which XRD patterns have been collected.Different symbols correspond to different Fe phases and

textures.

S. Anzellini et al. Science 2013;340:464-466Published by AAAS

Fig. 3 Phase stability domains for Fe obtained in the literature and in this study.The stability field for ε-Fe is based on the current study data and data from (19).

S. Anzellini et al. Science 2013;340:464-466Published by AAAS

Fig. 4 Temperature profile (geotherm) in the lower mantle and the outer core.Dark blue curve, solidus of pyrolite (this study); light green curves,

liquidus and solidus of pyrolite (7).

Ryuichi Nomura et al. Science 2014;343:522-525Published by AAAS

HJ Huang et al. Nature 479, 513-516 (2011) doi:10.1038/nature10621

The density–pressure relationships for Fe92.5O2.2S5.3 and Fe90O8S2.

HJ Huang et al. Nature 479, 513-516 (2011) doi:10.1038/nature10621

The bulk sound velocity as a function of density for Fe92.5O2.2S5.3 and Fe90O8S2.

HJ Huang et al. Nature 479, 513-516 (2011) doi:10.1038/nature10621

Density versus pressure and bulk sound velocity for Fe92.5O2.2S5.3, Fe90O8S2, Fe90O0.5S9.5 and pure iron along the adiabatic geotherm, compared with the PREM model.

Inner Core Anisotropy: different in the Eastern and Western Hemispheres

J Wookey & G Helffrich Nature 454, 873-876 (2008) doi:10.1038/nature07131

Source, ray path and receiver geometry.

J Wookey & G Helffrich Nature 454, 873-876 (2008) doi:10.1038/nature07131

PKJKP Data

a, Outer-core convection in Taylor columns leads to larger equatorial heat-flux, promoting freezing at the ICB in these regions. This is dynamically unstable, leading to deformation symmetrically about the rotation axis.

b, Crystal alignment due to dendritic solidification. As liquid iron freezes onto the ICB, dendrite structures might be formed and could persist deep into the inner core.

c, Alignment due to Maxwell stresses: stresses exerted by the Earth's magnetic field (B) re-orient crystals of inner-core iron, leading to large-scale texturing.[Wookey and Helffrich, 2008]

Possible models for Inner Core Anisotropy

Streamlines for the l = 1 pattern of convection in the inner core

Bruce A. Buffett Geophys. J. Int. 2009;179:711-719

[M. Bergman]

T Alboussière et al. Nature 466, 744-747 (2010) doi:10.1038/nature09257

A schematic representation of the translational convective mode.

Paths of the PKIKP wave (solid line) refracted inside the inner core and the PKiKP wave (dashed line) reflected at the inner-core boundary at distance 140°.

Marc Monnereau et al. Science 2010;328:1014-1017

Schematic cross-section illustrating the inner-core growth model.

Marc Monnereau et al. Science 2010;328:1014-1017

T Alboussière et al. Nature 466, 744-747 (2010) doi:10.1038/nature09257

Growth rate of the radius of the inner core and uniform convective velocity as functions of the inner-core radius.

Ray paths of PKP waves and example of waveform doublet used to detect temporal change of travel times through the inner core.

Jian Zhang et al. Science 2005;309:1357-1360Published by AAAS

Paths within the inner core for doublet events separated by more than 4 years, all of which show a positive time shift.

Jian Zhang et al. Science 2005;309:1357-1360

Difference of BC – DF times, d(BC – DF), at station COL as a function of the time separation between the two events of the doublet.

Jian Zhang et al. Science 2005;309:1357-1360Published by AAAS

Inner Core Rotation: Either east or west, with respect to mantle!

Tkalcic et al. [2013] find that it might do both (wobble).

Fig. 1 PKP ray paths and travel-time curves for a 1D reference model. Differential travel times between PKP(DF) and other three branches (AB, BC and CD) of PKP waves from 130° to 180° are used in this study.

Xinlei Sun , Xiaodong Song, Tomographic inversion for three-dimensional anisotropy of Earth’s inner core, Physics of the Earth and Planetary Interiors, Volume 167, Issues 1–2, 2008, 53 – 70, 2008.

Fig. 2 All differential PKP travel-time data used in this study. Plotted are residuals of differential CD–DF, BC–DF, and AB–DF relative to model AK135 with ellipticity correction. The data are divided according to distance range

Xinlei Sun , Xiaodong Song, Tomographic inversion for three-dimensional anisotropy of Earth’s inner core, Physics of the Earth and Planetary Interiors, Volume 167, Issues 1–2, 2008, 53 – 70, 2008.

Xinlei Sun , Xiaodong Song, Tomographic inversion for three-dimensional anisotropy of Earth’s inner core, Physics of the Earth and Planetary Interiors, Volume 167, Issues 1–2, 2008, 53 – 70, 2008.

Xinlei Sun , Xiaodong Song, Tomographic inversion for three-dimensional anisotropy of Earth’s inner core, Physics of the Earth and Planetary Interiors, Volume 167, Issues 1–2, 2008, 53 – 70, 2008.