First observations of nonhydrodynamic mix at the fuel-shell interface in shock-driven inertial confinement implosions

Area of Science:

• Nuclear Fusion Science
• Plasma Physics
• Materials Science

Background:

• Inertial confinement fusion (ICF) relies on precise implosions to achieve ignition.
• Fuel-shell mixing is a critical factor affecting ICF performance.
• Existing hydrodynamic models struggle to explain observed mixing phenomena in certain ICF scenarios.

Purpose of the Study:

• To investigate the mechanism behind significant fuel-shell mix in ICF implosions.
• To reconcile experimental observations with theoretical predictions of fusion yields.
• To identify non-standard mixing processes in shocked ICF targets.

Main Methods:

• Experiments involving strongly shocked inertial confinement fusion implosions of thin deuterated-plastic shells.
• Filling shells with 3He gas and comparing yields with hydroequivalent D3He gas mixtures.
• Utilizing hydrodynamic modeling to simulate mix and predict fusion yields.

Main Results:

• Observed D3He-proton shock yields comparable between 3He-filled and D3He-filled shells.
• Standard hydrodynamic mix models predicted yields an order of magnitude lower than experimental results.
• A strong nonhydrodynamic mechanism was identified as the cause of fuel-shell mix.

Conclusions:

• Ion diffusive mix at the fuel-shell interface is the dominant mechanism responsible for the observed fuel-shell mix.
• This nonhydrodynamic process significantly impacts fusion yields in ICF implosions.
• Understanding ion diffusive mix is essential for advancing ICF research and development.