Analysis of the National Ignition Facility ignition hohlraum energetics experiments

Symmetry tuning with megajoule laser pulses at the National Ignition Facility

“…The plot shows the tuning curves generated using the procedure described by Town et al [12] for both 1.0 and 1.3 MJ. The offset between the two tuning curves is a result of the different plasma conditions generated with the different laser energies.…”

“…This changes the radiation pattern driving the capsule implosion. Previous experiments at the National Ignition Facility have demonstrated control of the incident cone fraction via crossbeam energy transfer [7,8] that is determined by the difference in laser wavelength between the inner and outer beam cones [9][10][11][12]. This method employs scattering of the laser light from the outer beam cones to the inner beam cones via plasma waves driven ponderomotively by the beating of laser light.…”

“…This method employs scattering of the laser light from the outer beam cones to the inner beam cones via plasma waves driven ponderomotively by the beating of laser light. The methodology for computing the resulting incident cone fraction from hydrodynamic simulations is described by Town et al [12] and was developed by Michel et al [10].…”

Towards an integrated model of the NIC layered implosions

“…Tabular opacities and equation of state are used for the ablator and DT fuel. The input laser sources are adjusted to account for the backscattered energy and the crossbeam energy transfer that occurs in the hohlraum plasma [7,8]. The Monte Carlo particle transport package was used to generate realistic neutron spectra for simulated neutron diagnostics.…”

Ignition tuning for the National Ignition Campaign

“…Implosion velocities and the rocket-model-associated ablator mass remaining are measured using backlit x-ray radiography of the capsule limb [7] and can be adjusted using the peak power level, ablator thickness and dopant choice. Implosion symmetry is inferred from the soft x-ray reemission limb uniformity of a surrogate high Z sphere at early time ("Reemit") [8] and from core x-ray self-emission at pole and equator views at bangtime [9,10], and optimized using a combination a e-mail: landen1@llnl.gov This is an Open Access article distributed under the terms of the Creative Commons Attribution License 2.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.…”