Area density

National Ignition Facility

Quantum mechanics

Composite number

Engineering

Implosion

Aerospace engineering

Materials science

Nuclear physics

Operating system

Atomic physics

Plasma

Kinetic energy

Computer science

Carbon fibers

Classical mechanics

Nova (rocket)

Thermodynamics

Physics

Nuclear engineering

Hot spot (computer programming)

Inertial confinement fusion

Optics

Shell (structure)

Composite material

Mechanics

Ignition system

Physical Review Letters

Inertial confinement fusion implosions must achieve high in-flight shell velocity, sufficient energy coupling between the hot spot and imploding shell, and high areal density (ρR=∫ρdr) at stagnation. Asymmetries in ρR degrade the coupling of shell kinetic energy to the hot spot and reduce the confinement of that energy. We present the first evidence that nonuniformity in the ablator shell thickness (∼0.5% of the total thickness) in high-density carbon experiments is a significant cause for observed 3D ρR asymmetries at the National Ignition Facility. These shell-thickness nonuniformities have significantly impacted some recent experiments leading to ρR asymmetries on the order of ∼25% of the average ρR and hot spot velocities of ∼100 km/s. This work reveals the origin of a significant implosion performance degradation in ignition experiments and places stringent new requirements on capsule thickness metrology and symmetry.Received 4 August 2020Revised 22 October 2020Accepted 30 November 2020DOI:https://doi.org/10.1103/PhysRevLett.126.025002© 2021 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasInertial confinement fusionTechniquesParticle plasma measurementsX-ray imagingPlasma Physics

Evidence of Three-Dimensional Asymmetries Seeded by High-Density Carbon-Ablator Nonuniformity in Experiments at the National Ignition Facility