抄録
In this article, my doctoral thesis, Behavior of hydrogen in the interior of the planets and satellites, was reviewed. I especially focus on the results of sound velocity measurements for iron hydride with the high resolution inelastic X-ray scattering here. The density evolution of the sound velocity of dhcp-FeH has been determined up to 70 GPa at room temperature from inelastic X-ray scattering and X-ray diffraction measurements. I found that the relationship between compressional wave velocity and density changes due to a magnetic transition from ferromagnetic to nonmagnetic FeH and that the nonmagnetic phase only follows the Birch's law. Assuming an ideal two-component mixing model, the hydrogen content of the Earth's inner core is obtained to be 0.30～0.37 wt% H, which corresponds to FeH0.17～FeH0.20.
