Development of Spectral and Atomic Models for Diagnosing Energetic Particle Characteristics in Fast Ignition Experiments

797870 In the fast ignition concept for inertial fusion energy, high-intensity short-pulse lasers are used to create energetic particles (protons and relativistic electrons) that propagate to the fuel within a compressed capsule. The efficient transport of these energetic particles to the fuel is a key issue in fast ignition research. A combination of well-diagnosed experiments and well-tested simulation tools are needed in order to achieve a good understanding of energetic particle transport through dense plasmas, which is a prerequisite for fast ignition to become a viable option for inertial fusion. This project will develop and apply spectral and atomic physics models, to be used in concert with a state-of-the-art particle-in-cell code, to simulate diagnostic signatures associated with energetic particle transport in short-pulse laser experiments. The developed models will be applied to fast ignition-related short-pulse laser experiments to characterize the properties of energetic protons and electrons. A multi-dimensional collisional-radiative code will be used to compute images and spectra that can be directly compared with experimental measurements. In Phase I proton-impact ionization/excitation models will be added to a spectral radiation package; atomic modeling module will be designed for use within particle-in-cell codes; and proof-of-principal simulations, relevant to fast ignitor experiments, will be performed. Commercial Applications and Other Benefits as described by the awardee: The computational tools should be capable of simulating in detail the radiative and atomic processes in laser-produced plasmas. Their user-friendly features, along with their capability to provide for direct comparison between simulation and experimental measurements, should make these plasma simulation tools well-suited for use in university research projects, industrial research and development, and government laboratory applications. The software also should be applicable to radiation sources for extreme ultraviolet and x-ray lithography, plasma radiation sources used in defense research, magnetic fusion energy plasma diagnostics, and radiation sources developed for medical physics research and instrumentation.