2019 年 29 巻 2 号 p. 129-137
The permanent densification of SiO2 glass has long attracted considerable attention in various fields such as condensed-matter physics, materials science, and geophysics. We have conducted isotropic- and uniaxial-compression experiments and ab-initio molecular-dynamics simulations to understand the permanent densification. It has been clarified that the permanent densification can be interpreted as a phase transition in the intermediate-range order (the network structure of SiO4 tetrahedra) and it changes not only density but also plasticity. This article attempts to review the permanent densification of SiO2 glass and introduce an application to estimate the behavior of magma in the Earth's deep upper mantle, based on our recent researches.