Warm dense water in 100 GPa regime*

We have experimentally measured the pressure-volume-temperature equation-of-state and the optical reflectivity of water, which matches with the interior condition of the water-rich super Earth. Transition between the warm dense fluid water and the electronically conducting fluid, where its physical and chemical properties are changing dramatically ($\sim$100 GPa range) has been explored with experiments that can directly measure the temperature of the system. It is done by focusing strong laser onto a preloaded water. Understanding of the inner structure of such unique super-Earths would be a key constraint on the origin and evolution of exoplanetary systems.