EARTH In the literature: contested

Thermal conductivity of liquid iron alloy at core-mantle boundary conditions

In plain words

How well molten iron conducts heat under core pressures controls how much heat is left to stir the core. Calculations and lab experiments disagree by a large factor.

Precise statement

Determine the thermal conductivity $k$ of the outer-core Fe-Ni-light-element liquid at $P \sim 1.36e12\,\mathrm{dyn}/\mathrm{cm}^2$ and $T \sim 4000\,\mathrm{K}$. Ab initio calculations give $k$ of order $1e7\ \text{to}\ 2.5e7\,\mathrm{erg}/(\mathrm{s}\,\mathrm{cm}\,\mathrm{K})$ while some laser-heated diamond-anvil measurements give values near $3e6\,\mathrm{erg}/(\mathrm{s}\,\mathrm{cm}\,\mathrm{K})$. An answer is $k$ with about 20 percent uncertainty including light-element and electron-electron scattering contributions.

What would settle it

Concordant dynamic or static high-pressure transport measurements at core conditions and ab initio calculations including electron-electron scattering.

Status in the literature

Unverified note

Experiment-theory disagreement persists as of 2024 to 2025, with new calculations for Fe-H and Fe-Si alloys (e.g. arXiv:2408.04521).

See also