Study on a fuel layering sequence of the foam target for the FIREX project

To develop the fuel layering sequence for the FIREX cryogenic target, redistribution of surrogate fuel, solid H2 in a shell with cooling duration has been studied. Two kinds of dummy targets with a foam and a polystyrene shells (~800 μm and 2 mm in diameter, respectively) were tested. The solid H2 layer in the polystyrene shell was accumulated on the shell bottom as time elapsed. On the other hand, the foam shell had less elapsed time dependence than the polystyrene shell. Furthermore, elapsed time appeared to make the solid H2 layer uniform.