Simulation of Magnesium Oxide Behavior under High-Energy Impact

Magnesium oxide is one of many important materials that comprise the mantles of terrestrial planets. In this regard, its properties at high temperatures and pressures reflect the nature of the planetary interior. Shock wave loading of magnesium oxide with account for polymorphic phase transition in a pressure range of 325–400 GPa is numerically simulated using a thermodynamic equilibrium model. The parameters of the consistent equation of state for high- and low-pressure magnesium oxide phases (MgO I and MgO II) are determined. The thermodynamic parameters of these phases are simulated. The Hugoniots of single and double compression are constructed in a range of 1–1000 GPa, and the following parameters are calculated: heat capacity along the normal isobar, entropy as a function of temperature, and temperature along the Hugoniot. The simulation results are verified using data from experiments and calculations of other authors.