Microscopic evolution of solid-hydrogen shells under the ultrafast dynamic compression

Starting from the same initial structure, solid-hydrogen shells were dynamically compressed at different implosion velocities by performing large-scale molecular dynamic simulations to explore their microscopic evolution under the ultrafast dynamic compression. The ultrafast dynamic compression is revealed to prohibit the solid shell from the structural phase transition, while the phase transition is first initiated at the inner surface of the shell. A faster compression generates a higher pressure in the shell at a given convergence ratio by preventing the hydrogen atoms from ejecting out of the solid-hydrogen shell to release pressure. These results provide a glimpse of the microscopic scenario of the solid-hydrogen shell at early times during the ultrafast dynamic compression, suggesting that the implosion velocity must be carefully determined to mitigate the growth of hydrodynamic instabilities on the inner surface of the solid-hydrogen shell.