Experiments and multiscale simulations of laser propagation through ignition-scale plasmas

With the next generation of high-power laser facilities for inertial fusion coming online(1,2), ensuring laser beam propagation through centimetre-scale plasmas is a key physics issue for reaching ignition. Existing experimental results(3-5) including the most recent one(6) are limited to small laser spots, low-interaction laser beam energies and small plasma volumes of 1-2 mm. Here, we demonstrate the propagation of an intense, high-energy, ignition-size laser beam through fusion-size plasmas on the National Ignition Facility (NIF) and find the experimental measurements to agree with full-scale modelling. Previous attempts to apply computer modelling as a predictive capability have been limited by the inherently multiscale description of the full laser-plasma interaction processes(7-11). The findings of this study validate supercomputer modelling as an essential tool for the design of future ignition experiments.