Geophysical background

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Thermal conductivity of iron under Earths core
conditions
Zuzana Konôpková

• Geophysical background
• Experimental tools
• Theory and Modeling
• Summary
• Whats next?

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Geophysical background
Introduction

• Birch, 1952 outer core liquid iron alloy
• inner core crystalline iron

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Thermal evolution
Introduction
Thermal conductivity!
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Realization

• Experimental part create high-pressure,
  high-temperature conditions in the sample

• Theoretical part
• model propagation of the heat within the sample

Derive thermal conductivity of iron under
Earths core conditions
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Experimental tools

• High pressure
• up to 150 GPa
• diamond anvil cell
• High temperature
• 2000 3000 K
• laser heating

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Diamond anvil cell
Experimental tools

• diamond anvil cell for static compression Peter
  Lazors design

sample
4 mm
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Laser heating
Experimental tools

• Nd-doped Yttrium-Aluminum-Garnet (YAG) laser
• ?1.06 µm
• Gaussian profile (TEM00 mode)

YAG
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Thermal conductivity
T0
Q

• Thermal conductivity heat flow rate distance
  / (area temperature difference)
• Equation of heat

T1
T - temperature q - heat source A - area L -
thickness Q - heat
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Modeling with Comsol multiphysics
Theory
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Modeling with Comsol multiphysics
Theory
heated side of the sample
unheated side of the sample
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Summary

• Experiment
• Known variables
• total laser power
• thickness of the sample
• radial temperature gradients
• Unknown variable
• thermal conductivity

• Model
• Input
• heat source
• geometry
• thermal conductivity
• Output
• radial and axial temperature profiles

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Whats next?
Conclusion

• Preparing for experiment
• loading samples
• optical setup
• alignment
• Double-side heating
• Experimental setup at synchrotron facilities

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THANK YOU