Measurements of Rayleigh–Taylor instability growth of laser-shocked iron–silicon alloy

ABSTRACT

The Rayleigh–Taylor (RT) instability of liquid iron alloys is important for understanding the core formation mechanism in the Earth. Here we first report the measurement of RT instability growth for a liquid iron–silicon (Fe–Si) alloy, which is one of the major candidate for the material of the Earth’s core, using a high power laser. We optimized the measurement setup and analytical technique to observe the growth of perturbation on an Fe–Si sample surface. The growth of perturbation amplitude on the Fe–Si alloy under high pressure and temperature was successfully observed using in situ X-ray radiography. The growth rate of the RT instability for the Fe–Si alloy on about 1000 GPa was estimated to be 0.3 ns⁻¹.

KEYWORDS:

• Iron alloy
• Rayleigh–Taylor instability
• Earth’s core
• laser
• X-ray radiography

Acknowledgments

This study was performed under the joint research project of the Institute of Laser Engineering, Osaka University. The authors would like to acknowledge the dedicated technical support by the staff at the GEKKO-XII facility for the laser operation, target fabrication, and plasma diagnostics.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This study was partly supported by a Grant-in-Aid for scientific research from the Ministry of Education, Culture, Science, Sport and Technology of the Japanese Government to H. T. [grant numbers 26610141, 26247089].