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
- Related When did Earth's solid inner core begin to grow?
- Related Which light elements make Earth's core less dense than iron?
- Related Electron thermal and electrical conductivity of warm dense matter
- Related What powered the geodynamo before the inner core existed?
- Related Is the top of Earth's liquid core stably stratified?