[Matsuo et al. "Petapascal pressure driven by fast isochoric heating with a multipicosecond intense laser pulse." Physical Review Letters (2020)]

This work shows a new way to reach extremely high pressures - on the order of petapascals - in a small volume of matter using a powerful, multi-picosecond laser pulse. By first compressing a dense plasma core, then rapidly heating it with a petawatt-class laser (several kilojoules total energy), and using strong magnetic fields (kilotesla level) to better guide the energetic electrons into the core, they heated the material to keV temperatures at near solid-density. The energy required (≈ 4.6 kJ) is much less than that required by conventional implosion (compression) methods to reach comparable pressures, making this “fast isochoric heating” scheme an efficient way to create ultra-high energy density (UHED) states. In addition, simulations show that thermal diffusion (i.e. heat moving from hot outer regions into the dense core) is a key mechanism in achieving the heating, not just direct deposition by energetic electrons.