惑星物質の衝撃圧縮その場状態計測

抄録

Shock-compressed high-pressure states of planetary materials have been analyzed using high-power lasers and ultrafast diagnosctic schemes in combination. Here we review our recent results. Uranus and Neptune in the outer solar system are made of planetary ice materials made of hydrogen, oxygen, carbon and nitrogen. At high pressure and temperature conditions relevant to the interiors of these planets, the planetary ices were proved to become a good electronic conductor, which is the best-possible rationale of strong magnetic fields originating from insides of these planets. On the other hand, microscopic structure evolution of planetary minerals, as represented by α-Mg₂SiO₄, are being analyzed as a function of time during their shock compression. For this purpose, X-ray free electron laser has been successfully combined with a high-power laser to enable ultrafast diffraction analysis of relevant crystal structures.