Japan Geoscience Union Meeting 2019

Presentation information

[E] Oral

S (Solid Earth Sciences ) » S-IT Science of the Earth's Interior & Techtonophysics

[S-IT25] Planetary cores: Structure, formation, and evolution

Thu. May 30, 2019 9:00 AM - 10:30 AM A09 (TOKYO BAY MAKUHARI HALL)

convener:Hidenori Terasaki(Graduate School of Science, Osaka University), Eiji Ohtani(Department of Earth and Planetary Materials Science, Graduate School of Science, Tohoku University), William F McDonough(University of Maryland College Park), George Helffrich(Earth-Life Science Institute, Tokyo Institute of Technology), Chairperson:George Helffrich(ELSI, Tokyo Institute of Technology), Hidenori Terasaki

10:00 AM - 10:15 AM

[SIT25-05] In situ observation of Rayleigh–Taylor instability growth of liquid Fe-Si using laser shock

*Hidenori Terasaki1, Tatsuhiro Sakaiya1, Keisuke Shigemori2, Hiroki Kato2, Yoichiro Hironaka2, Tadashi Kondo1 (1.Graduate School of Science, Osaka University, 2.Institute of Laser Engineering, Osaka University)

Keywords:Core formation, Rayleigh–Taylor instability, liquid Fe-alloy

Rayleigh–Taylor instability occurs at the interface between two fluids with different densities when a heavy fluid overlies a light one in a gravitational field. The RT instability is considered as one of the important core formation mechanism beneath the magma ocean. This mechanism has been discussed from simulations (e.g., Honda et al. 1993, Ricard et al. 2009) and analog experiment (e.g., Olson and Weeraratne, 2008). However, experimental approach using liquid Fe-alloys for this mechanism has never been performed under high pressure. In this study, we applied the laser-shock technique to observe in situ the Rayleigh–Taylor instability of liquid Fe-Si alloy under high pressure. The growth of the Rayleigh–Taylor instability was successfully observed using in situ x-ray radiography under shock compression. The growth rate of the Rayleigh–Taylor instability was estimated to 0.3 ns−1. The present results provide useful information to constrain the time scale of the Earth’s and planetary core formation.