Measurement of thermal conductivity in laser-heated diamond anvil cell using radial temperature distribution

ABSTRACT

Thermal conductivities of planetary materials under extreme conditions are important input parameters for modeling planetary dynamics such as accretion, geodynamo and magnetic field evolution, plate tectonics, volcanism-related processes etc. However, direct experimental measurements of thermal conductivity at extreme conditions remain challenging and controversial. Here we propose a new technique of thermal conductivity measurement in laser-heated diamond anvil cell (LH-DAC) based on radial temperature distribution around laser focal spot, mapped by imaging tandem acousto-optical tunable filter (TAOTF). The new technique provides much more information about heat fluxes in the laser-heated sample than existing static heating setups, and does not require dynamic numerical modeling using heat capacities in contrast to dynamic pulsed heating setups. In the test experiment, thermal conductivity of γ-Fe at conditions relevant to cores of terrestrial planets was measured.

KEYWORDS:

• Thermal conductivity
• iron
• high pressure
• LH-DAC
• TAOTF

Acknowledgements

The authors gratefully thank Ivan A. Trojan for kind assistance in the preparation of DAC. The reported study was funded by RFBR according to the research project #18-35-20047 and performed using the Unique Scientific Instrument ‘Laser heating in diamond anvil cell' (http://ckp-rf.ru/usu/507563/). Numerical modeling was performed using infrastructure supported by the state assignment of IGM SB RAS.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The reported study was funded by RFBR according to the research project #18-35-20047.