Fundamental Study of Wave Propagation on Liquid Surface Related IFE Mirror

A laser fusion reactor needs an optical mirror in its final optical system. This optical mirror is exposed to the neutron produced with fusion reaction. It is pointed out that the exposure to neutron will produce hydrogen gas in the mirror and cause swelling deformation of mirror. To avoid this swelling of mirror, a liquid-metal mirror is promising. High energy laser shots on the liquid mirror will cause the surface wave. These waves must be damped to under 1/10 of the laser wavelength in 250 ms or less. In this study, the hydrodynamic behavior of the liquid surface was investigated by experiment with water as surrogate liquid, the computational evaluation for the wave propagation with the MARS (Multi-interface Advection and Reconstruction Solver, 2001) was carried out, and the design window for the optical mirror based on the water experiment was discussed.