Temperature gradients in the laser‐heated diamond anvil cell

Panero, W. R.; Jeanloz, Raymond

doi:10.1029/2000jb900423

Cited by 37 publications

(30 citation statements)

References 14 publications

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“…Error assessment in the thermal conductivity determination. The laser-heated DAC in combination with numerical simulations has been shown to be a promising tool for studying heat transfer at high pressures and temperatures 11,12,26,30,[47][48][49][50] . This approach requires a detailed understanding of heat transfer in the DAC, including quantitative relationships between the temperature distribution, pressure chamber geometries and sample physical properties.…”

Section: Letter Researchmentioning

confidence: 99%

Direct measurement of thermal conductivity in solid iron at planetary core conditions

Konôpková

McWilliams

Pérez

et al. 2016

Nature

249

223

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The conduction of heat through minerals and melts at extreme pressures and temperatures is of central importance to the evolution and dynamics of planets. In the cooling Earth's core, the thermal conductivity of iron alloys defines the adiabatic heat flux and therefore the thermal and compositional energy available to support the production of Earth's magnetic field via dynamo action. Attempts to describe thermal transport in Earth's core have been problematic, with predictions of high thermal conductivity at odds with traditional geophysical models and direct evidence for a primordial magnetic field in the rock record. Measurements of core heat transport are needed to resolve this difference. Here we present direct measurements of the thermal conductivity of solid iron at pressure and temperature conditions relevant to the cores of Mercury-sized to Earth-sized planets, using a dynamically laser-heated diamond-anvil cell. Our measurements place the thermal conductivity of Earth's core near the low end of previous estimates, at 18-44 watts per metre per kelvin. The result is in agreement with palaeomagnetic measurements indicating that Earth's geodynamo has persisted since the beginning of Earth's history, and allows for a solid inner core as old as the dynamo.

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Section: Letter Researchmentioning

confidence: 99%

Direct measurement of thermal conductivity in solid iron at planetary core conditions

Konôpková

McWilliams

Pérez

et al. 2016

Nature

249

223

View full text Add to dashboard Cite

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“…Although large temperature gradients are always present at the edges of the circular heated region, this heating geometry promotes uniform heating both radially and axially within the heated region [22] and [23]. Temperature was measured on one side using conventional spectroradiometric techniques as described in detail elsewhere [24].…”

Section: Experimental Methodsmentioning

confidence: 99%

Subsolidus phase relations and perovskite compressibility in the system MgO–AlO1.5–SiO2 with implications for Earth's lower mantle

Walter¹,

Trønnes²,

Armstrong³

et al. 2006

Earth and Planetary Science Letters

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Experimentally determined phase relations in the system MgO-AlO1.5-SiO2 at pressures relevant to the upper part of the lower mantle indicate that Mgsilicate perovskite incorporates aluminum into its structure almost exclusively by a charge-coupled reaction. MgSiO3-rich bulk compositions along the joins showing unusually compressive aluminous perovskite. The maximum solubility of alumina in perovskite is ∼25 mol% along the MgSiO3-AlO1.5 join within the ternary MAS-system (i.e. pyrope composition), and the join is apparently binary.Although primitive mantle peridotite compositions are MgO-saturated and fall nearly on the oxygen vacancy join, alumina substitution into perovskite is expected to occur primarily by charge-coupled substitution throughout the lower mantle. The compressibility of aluminous perovskite in primitive mantle is expected to be only a few percent lower than for end member MgSiO3 perovskite.

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“…Although the analytical model domain is not exactly equivalent to the numerical model, which explicitly includes the effects of the diamond anvils and metal gasket, it was shown to closely replicate the temperature profiles from previous numerical simulations. 9 The assumption of ambient-temperature boundaries has also been demonstrated to be valid by previous numerical models, which have shown that the temperature within a laser-heated diamond cell drops to nearambient at the surfaces of the diamond anvils in the axial direction (z, parallel to laser beam) and within the sample chamber in the radial direction (r, perpendicular to laser beam) [e.g., Ref. 6].…”

Section: Validation Of Numerical Solutionmentioning

confidence: 84%

“…Although samples within the diamond cell do radiate some energy away (indeed, the typical method of temperature measurement in LHDAC experiments is spectroradiometry), the extreme temperature gradients mean that lattice conduction is expected to be the dominant mechanism of heat transport within the diamond cell in most experiments, and measured temperature gradients are consistent with heat transport by phonons. [8][9][10][11] The steady-state heat conduction equation has been shown to be appropriate to describe heat flow within the LHDAC for continuous heating experiments and has been used in previous models [e.g., Refs. 8 and 9].…”

Section: A Lhdac Thermal Environmentmentioning

confidence: 99%

Temperature distributions in the laser-heated diamond anvil cell from 3-D numerical modeling

Rainey¹,

Hernlund

Kavner³

2013

Journal of Applied Physics

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The effect of sample thickness and insulation layers on the temperature distribution in the laser-heated diamond cell Rev. Sci. Instrum. 72, 1306 10.1063/1.1343863 Temperature and pressure distribution in the laser-heated diamond-anvil cell Rev. Sci. Instrum. 69, 2421 (1998); 10.1063/1.1148970Numerical calculations of the temperature distribution and the cooling speed in the laser-heated diamond anvil cellWe present TempDAC, a 3-D numerical model for calculating the steady-state temperature distribution for continuous wave laser-heated experiments in the diamond anvil cell. TempDAC solves the steady heat conduction equation in three dimensions over the sample chamber, gasket, and diamond anvils and includes material-, temperature-, and direction-dependent thermal conductivity, while allowing for flexible sample geometries, laser beam intensity profile, and laser absorption properties. The model has been validated against an axisymmetric analytic solution for the temperature distribution within a laser-heated sample. Example calculations illustrate the importance of considering heat flow in three dimensions for the laser-heated diamond anvil cell. In particular, we show that a "flat top" input laser beam profile does not lead to a more uniform temperature distribution or flatter temperature gradients than a wide Gaussian laser beam. V C 2013 AIP Publishing LLC. [http://dx.

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Temperature gradients in the laser‐heated diamond anvil cell

Cited by 37 publications

References 14 publications

Direct measurement of thermal conductivity in solid iron at planetary core conditions

Direct measurement of thermal conductivity in solid iron at planetary core conditions

Subsolidus phase relations and perovskite compressibility in the system MgO–AlO1.5–SiO2 with implications for Earth's lower mantle

Temperature distributions in the laser-heated diamond anvil cell from 3-D numerical modeling

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