Model calculations of the temperature distribution in the laser-heated diamond cell

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Abstract
Numerical calculations are used to simulate the steady-state temperature distribution achieved during cw laser heating of a dielectric sample inside the high-pressure diamond cell. According to the results, the temperature field is controlled in the radial direction by the dimension (profile) of the laser beam; in the axial direction it is controlled by heat loss to the diamond anvils. Thus, the peak temperature is approximately proportional to sample thickness. The temperature distribution is nearly Gaussian in both the radial and axial directions, especially near the center of the hot zone in the sample. For typical experimental conditions, peak temperatures exceeding 5000 K and temperature gradients of ∼108–109 K/m are expected, with radial and axial dimensions of the hot zone being ∼20 and ∼10 μm, respectively. These values are in accord with experimental measurements, and they imply that despite the high temperatures achieved inside the sample volume the surrounding diamond anvils remain essentially at ambient temperatures.