Mixing with applications to inertial-confinement-fusion implosions

Area of Science:

• Plasma Physics
• Computational Physics
• Fusion Energy

Background:

• One-dimensional (1D), 2D, and 3D simulations are crucial for designing and analyzing experiments at the National Ignition Facility (NIF).
• 1D simulations are particularly important for design optimization in inertial confinement fusion (ICF).

Purpose of the Study:

• To investigate the potential for mix in National Ignition Campaign (NIC) designs using coupled 1D simulation codes.
• To assess the impact of modeling errors, design features, and unmodeled instabilities on fusion performance.

Main Methods:

• Coupling a 1D buoyancy-drag mix model with a 1D ICF simulation code.
• Developing a package of plasma transport parameters relevant to NIC experiments.
• Analyzing multimode plastic (CH) mix into deuterium-tritium (DT) hot-spots.

Main Results:

• NIC designs are predicted to be close to a performance cliff, sensitive to mix effects.
• Single instabilities are unlikely to cause hot-spot mix, but combined effects can impact hot-spot thermodynamics.
• Potential mix effects include interactions with the DT ice-gas boundary, Eulerian diffusion, and ablation-driven instabilities.

Conclusions:

• Combined mode mixing effects, coupled with stagnation Rayleigh-Taylor instability, pose a risk to hot-spot performance.
• The developed plasma transport parameters help approximate quantities and rule out certain mix possibilities.
• Accurate modeling of mix is essential for optimizing ICF designs and achieving ignition.