Three-Dimensional Numerical Simulations of the LAPLAS Target Including Elastic-Plastic Effects

The LAPLAS experimental scheme (beam-target geometry) is shown in Fig. 1. It is a multi-layered target that consists of s solid cylinder of frozen hydrogen that is enclosed in a cylindrical shell of a high-Z material like Pb or Au. One face of this target is irradiated with an intense ion beam that has an annular focal spot whose dimensions are chosen in such a way that the hydrogen is not directly heated by the ion beam. Moreover a small ring shaped part of the surrounding shell is left around the hydrogen which is called ”payload”. The high pressure in the beam heated region leads to a low-entropy compression of the hydrogen. Previously [1, 2, 3] we carried out two-dimensional hydrodynamic simulations of implosion of the LAPLAS target that showed that in most of the cases, the payload shell will remain in solid state and hence will retain its elastic properties. Analytic work [4] has shown that elasticity will have stabilizing effect on the Rayleigh-Taylor instability of the payload shell. In the previous simulations, elastic-plastic effects were not included. We have now carried out threedimensional numerical simulations of the LAPLAS target implosion that also include elastic-plastic effects. These calculations show that the implosion dynamics is rather insensitive to inclusion of these additional physical effects.