[S-IT03] Structure and dynamics of Earth and Planetary deep interiors

[SIT03-23] 高圧下における液体Fe-C合金の音速測定

*中島 陽一¹、今田 沙織²、廣瀬 敬²、駒林 鉄也³、小澤 春香⁴、舘野 繁彦²、桑山 靖弘⁵、筒井 智嗣⁶、Alfred Baron¹ (1.理化学研究所放射光科学総合研究センター、2.東京工業大学地球生命研究所、3.エジンバラ大学地球科学科、4.独立行政法人海洋研究開発機構、5.愛媛大学球深部ダイナミクス研究センター、6.独立行政法人高輝度光科学研究センター)

The liquid Earth’s outer core consists predominantly of iron with c.a. 10 wt.% lighter elements, such as hydrogen, carbon, oxygen, silicon, and sulfur. Other terrestrial planets such as Mars, Mercury and Venus are also similar to the Earth in that they have a central metallic core, which are considered to be at least partially molten. Popular models for those planetary cores also favor the existence of lighter elements. The nature of the light elements is important for understanding the acient core formation processes and the present core structure and dynamics in terrestrial planets, which are still not well understood. The seismic wave speed is the primary information on the Earth’s core. The sound velocity of liquid Fe alloying with light-elements is therefore key to constrain the lighter component in the Earth’s core and will be referenced for the future survey of other planets. Recently we have developed the techniques for inelastic X-ray scattering (IXS) measurements combined with diamond-anvil cell (DAC) experiments at the SPring-8 synchrotron facility, in order to investigate sound velocities of liquid Fe alloying with light-elements under high pressure and high temperature conditions relevant to planetary cores. We determined sound velocities of liquid Fe-C alloy up to 70 GPa. We will discuss the effect of carbon on sound velocity of liquid iron and on planetary cores.