Using time-resolved nuclear diagnostics to probe kinetic/multi-ion physics and shock dynamics on OMEGA and the NIF

Abstract

This thesis focuses on the development and application of time-resolved nuclear diagnostics to probe plasma evolution in Inertial Confinement Fusion (ICF) implosions. On the OMEGA laser facility at the Laboratory for Laser Energetics (LLE) in Rochester, New York, the impact of kinetic and multi-ion effects on ICF implosion performance is studied using the Particle X-ray Temporal Diagnostic (PXTD). PXTD is a versatile streaked instrument for measurements of multiple X-ray-emission and nuclear-reaction histories with high relative timing precision, and developed to probe the time evolution of plasma conditions during the shock phase of ICF implosions. Assessing the roles kinetic and multi-ion effects play in ICF implosions is especially important because ICF implosion simulations heavily rely on radiation-hydrodynamic codes that do not model these effects. However, most experimental results thus far made use of only time-integrated observables. Using PXTD, time-resolved observations of fuel-ion species dynamics in ICF implosions have been made using multiple nuclear reaction histories. These time-resolved measurements have also been extended to infer ion and electron temperature histories in ICF implosions. On the National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory (LLNL), implosion dynamics from shock to compression are probed using the magnetic particle time-of-flight (magPTOF) diagnostic. magPTOF is designed to simultaneously measure the shock and compression timings in D 3 He-gas-filled implosions on the NIF. In combination with other nuclear and X-ray diagnostics, magPTOF is used to assess areal density, areal density asymmetry, implosion velocity, and mix.