Ultradense hydrogen in astrophysics, high-pressure metal physics and fusion studies

Phase diagrams of hydrogen are constructed through first-principles calculations of the equations of state for metallic and insulator phases. On the bases of these theories of the equations of state and the electric resistivity, it is shown that the results of recent shock-metallization experiments can be consistently interpreted in terms of first-order metal-insulator transitions, involving discontinuous changes in density, entropy and enthalpy. The first-order transitions then predict a discontinuous distribution of density and resistivity near the Jovian surface, with a large magnetic Reynolds number enough to sustain prominent magnetic activities. A phase diagram for freezing and ferromagnetic transitions provides a basic account of strong magnetization observed in magnetic white dwarfs. Feasibility of a novel scheme of fusion studies in ultradense metallic hydrogen is examined in light of these experimental and theoretical developments