J. Helfrich,
J. Vorberger,
S. Frydrych,
G. Schaumann,
A. Ravasio,
M. Gauthier,
L. Fletcher,
B. Nagler,
B. Barbrel,
B. Bachmann,
E. Gamboa,
S. Göde,
E. Granados,
H. Lee,
P. Neumayer,
W. Schumaker,
T. Döppner,
R. Falcone,
S. Glenzer,
M. Roth,
and D. Kraus
Investigation of the temperature in dense carbon near the solid-liquid phase transition between 100 GPa and 200 GPa with spectrally resolved X-ray scattering
HEDP, 32 :56 (July 2019)
Investigation of the temperature in dense carbon near the solid-liquid phase transition between 100 GPa and 200 GPa with spectrally resolved X-ray scattering
HEDP, 32 :56 (July 2019)
Abstract:
We present experiments investigating dense carbon at pressures between 100 GPa and 200 GPa and temperatures between 5,000 K and 15,000 K. High-pressure samples with different temperatures were created by laser-driven shock compression of graphite and varying the initial density from 1.53 g/cm³ to 2.21 g/cm³ and the drive laser intensity from 7.1 TW/cm² to 14.2 TW/cm². In order to deduce temperatures, spectrally resolved X-ray scattering was applied to determine ion-ion structure factors at a scattering vector of k = 4.12x10¹⁰ m⁻¹ which shows high sensitivity to temperature for the investigated sample conditions. After comparison to corresponding DFT-MD simulations, we were able to assign each structure factor a temperature. This information is indicative of the expected temperature range for the melting line of carbon at high pressures and can be compared to theoretical predictions.