Markers of Ignition: Nuclear Imaging of Inertial Confinement Fusion Experiments

In inertial confinement fusion (ICF) capsules filled with Deuterium and Tritium fuel are compressed using lasers to reach temperatures and pressures necessary for fusion reactions to occur. Los Alamos National Laboratory's (LANL) Physics Division provides the primary nuclear diagnostics to study ICF implosions at the National Ignition Facility (NIF) – the most powerful ICF facility in the world. In recent breakthrough ignition experiments LANL diagnostics have shown markers of the burning plasma under extreme conditions. This transition into the ignition era is setting new challenges for diagnostics but allowing researchers a glimpse into never before accessed physics regimes. The neutron imaging system visualizes the burning hot spot shape in 3D. Two neutron energy-gated lines-of-sight determine the cold fuel density surrounding the burning fuel. The first gamma imaging system in ICF creates the opportunity to measure the remaining ablator position and density. Together, these complex diagnostics make up a complete nuclear imaging suite which opens a window into the shape characteristics of fusion implosions. The nuclear imaging diagnostic has significantly advanced our understanding of performance limitations in ICF and is now providing images of ignition shots.