[S-IT39_2AM2] 地球深部ダイナミクス：プレート・マントル・核の相互作用

[SIT39-09] 核条件下でのhcp-Feの音速・密度測定

*坂巻 竜也¹、大谷 栄治¹、福井 宏之²、鎌田 誠司¹、高橋 豪¹、坂入 崇紀¹、高畑 明拓¹、境 毅³、筒井 智嗣⁴、BARON Alfred⁵ (1.東北大、2.兵庫県立大、3.愛媛大、4.SPring-8/JASRI、5.理研)

キーワード：地球核, 音速, 密度, 高温高圧, X線非弾性散乱, レーザー加熱式ダイヤモンドアンビルセル

Sound velocity measurements of Fe and Fe-alloy at high temperature and high pressure are necessary to understand the Earth's inner core. Despite seismological observations providing density-sound velocity data of Earth's core, there are few experimental reports about sound velocity of hcp-Fe at ultrahigh pressure and temperature conditions. In order to push forward with research, we have developed a portable laser-heating system for diamond anvil cell, which is called COMPAT (Fukui et al., 2013). We have succeeded in measuring the sound velocity of hcp-iron up to 160 GPa and 3000 K by inelastic X-ray scattering measurements combining with a laser-heated diamond anvil cell. The obtained pressure and temperature dependence of the sound velocity suggest that compressional sound velocity of hcp-Fe at inner core boundary (330 GPa and 5500 K) is higher than that of Earth's inner core. Thus, we can conclude that the light elements or combination of the light elements and nickel in the inner core decreases both density and compressional sound velocity of hcp-Fe simultaneously under the inner core conditions.ReferenceFukui et al., 2013. A compact system for generating extreme pressures and temperatures: An application of laser-heated diamond anvil cell to inelastic X-ray scattering. Review of Scientific Instruments 84, 113902; doi: 10.1063/1.4826497.