Interaction of laser radiation with a porous medium and formation of a nonequilibrium plasma

A theory of the interaction of a powerful laser radiation pulse with a low-density porous material is proposed. This theory describes satisfactorily the experimental results. It is shown that internal evaporation of the solid components of such a material into the surrounding cavities of the medium leads to interesting features of the interaction of a laser pulse with the medium: formation of a region of radiation absorption under conditions of increasing geometric opacity of the material, volume absorption of laser radiation in the material of density higher than the critical plasma density, and formation of a nonequilibrium plasma with a preferentially heated ionic component. A hypothesis is put forward and justified that it should be possible to construct a powerful neutron source operating on the basis of laser excitation of hydrothermal dissipation in a spatially structured medium.