[S-IT03_29PM1] Structure and dynamics of Earth and Planetary deep interiors

[SIT03-20] 高圧下における合金融体の音速と密度の関係

*寺崎 英紀¹、西田 圭佑²、浦川 啓³、桑原 荘馬¹、田窪 勇作¹、下山 裕太¹、上杉 健太朗⁴、竹内 晃久⁴、鈴木 芳生⁴、河野 義生⁵、肥後 祐司⁴、近藤 忠¹ (1.Osaka Univ.、2.Univ. Tokyo、3.Okayama Univ.、4.JASRI、5.HPCAT)

キーワード：音速, 密度, 液体, 高圧

It is important to understand the relationship between sound velocity and density of liquid Fe-alloys under high pressure for obtaining a constraint of the composition of the molten outer core from observed seismic data. We have studied a relationship between sound velocity and density of liquid alloy based on simultaneous measurement of these properties under high pressure and high temperature. Sound velocity was measured using ultrasonic pulse-echo overlapping method and density was measured employing X-ray absorption method combined with X-ray tomography technique. The measured P-wave velocity and density of liquid Ni?S both increase with pressure. From these data, adiabatic bulk modulus (K_S0) of the liquid sample can be well constrained to 29 GPa. It is note that the measured P-wave velocity is found to increase linearly with increasing density. This result provides an important issue in terms of Birch's law for liquid material.