Dynamic X-ray diffraction observation of shocked solid iron up to 170 GPa

Adrien Denoeud (1) , Ozaki Norimasa , Benuzzi-Mounaix Alessandra , Uranishi H. , Kondo Y , Kodama R , Brambrink E , Ravasio A , Bocoum M , Boudenne Jm , Harmand Marion , Guyot F , Mazevet S , Riley D , Makita M , Sano T , Sakawa Y , Y. Inubushi , Gregori G , Koenig M , Guillaume Morard

1 LULI - Laboratoire pour l'utilisation des lasers intenses

Investigation of the iron phase diagram under high pressure and temperature is crucial for the determination of the composition of the cores of rocky planets and for better understanding the generation of planetary magnetic fields. Here we present X-ray diffraction results from laser-driven shock-compressed single-crystal and polycrystalline iron, indicating the presence of solid hexagonal close-packed iron up to pressure of at least 170 GPa along the principal Hugoniot, corresponding to a temperature of 4,150 K. This is confirmed by the agreement between the pressure obtained from the measurement of the iron volume in the sample and the inferred shock strength from velocimetry deductions. Results presented in this study are of the first importance regarding pure Fe phase diagram probed under dynamic compression and can be applied to study conditions that are relevant to Earth and super-Earth cores.

Mots clés: laser compression; Iron Phase Diagram; Earth Core

Domaines: Géophysique [physics.geo-ph]; Science des matériaux [cond-mat.mtrl-sci]; Physique des plasmas [physics.plasm-ph]

Adrien Denoeud, Ozaki Norimasa, Benuzzi-Mounaix Alessandra, Uranishi H., Kondo Y, et al.. Dynamic X-ray diffraction observation of shocked solid iron up to 170 GPa. Proceedings of the National Academy of Sciences of the United States of America, 2016, ⟨10.1073/pnas.1512127113⟩. ⟨hal-01393338⟩