CC BY
9LP-I-18
Laser interactions with low density porous matter - experiment and modelling
J. Limpouch1
1Czech Technical University in Prague, Faculty of Nuclear Sciences and Physical Engineering, Praha 8, Czech Republic
Porous solid media enable decreasing and tuning the average density of solid materials. Laser interactions with porous matter have a broad range of applications. Laser interaction with porous layers may be used both in direct-drive and in indirect-drive inertial confinement fusion (ICF). Enhancement of shock wave pressure by low density layers is used in studies of equation of state. Long homogeneous plasmas created from porous materials may be used as an efficient X-ray source and also for investigation of physics relevant to shock ignition of ICF; nearly critical plasmas are used for laser-driven ion acceleration and radiation sources.
We will briefly describe various available types of porous matter. Then, several interaction experiments will be reviewed and I shall present preliminary results of our recent experiment in the PALS laboratory where foam homogenization was studied.
Numerical modelling of laser interactions with porous materials is a very difficult task due to large differences in the scales involved - solid elements thickness typically of order tens of nanometres, pore dimension of order of a few microns and macroscopic interaction scale typically of order hundreds of microns. Moreover, typical porous materials have three-dimensional structure. Thus, including detailed structure of a porous material into numerical simulations of macroscopic experiments is beyond present capabilities. On the other hand, simple substitution of porous matter by a homogeneous material of the same average density leads to large discrepancies between experiment and simulations due to omission of the homogenization process. Our and other models for including the homogenization process into fluid simulations of laser-target interactions are described and simulation results are compared with experiments.
