The Gated X-ray Detector for the National Ignition Facility

Oertel, J A; Barnes, C; Archuleta, T; Casper, L; Fatherley, V; Heinrichs, T; King, R; Landers, D; Lopez, F; Sanchez, P; Sandoval, G; Schrank, L; Walsh, P; Bell, P; Brown, M; Costa, R; Holder, J; Montalongo, S; Pederson, N

doi:10.2172/896014

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(1 citation statement)

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“…3 (b). The change in l = 2 moment (P2) between the inflight and hot spot symmetry [45] (non-conformal P2) for N170706 is thought to be due to cooling of the outer regions of the hot spot. This experiment used the same target configuration and pointing, same hohlraum gas fill density (0.6 mg/cc), similar laser energy (N150826∼1.42MJ vs N170706∼1.46 MJ), similar pulse length (N150826∼13.6ns vs N170706∼13.2ns), and similar laser cone fraction during the peak of the pulse (N150826∼34% vs N170706∼35%).…”

Section: 2mentioning

confidence: 99%

Energy transfer between lasers in low-gas-fill-density hohlraums

et al. 2018

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We investigate cross beam energy transfer (CBET), where power is transferred from one laser beam to another via a shared ion acoustic wave, for the first time in hohlraums with low gas fill density as a tool for late-time symmetry control for long pulse (>10ns) Inertial Confinement Fusion (ICF) and laboratory astrophysics experiments. We show that the radiation drive symmetry can be controlled and accurately predicted during the foot of the pulse (until the rise to peak power), which is important for mitigating areal density variations in the compressed fuel in ICF implosions. We also show that the effective inner beam drive after CBET is much greater than observed in previous high gas-filled hohlraum experiments, which is thought to be a result of less inverse bremsstrahlung absorption of the incident laser light and reduced (>10x) Stimulated Raman Scattering (SRS) (and Langmuir wave heating). With the inferred level of inner beam drive after transfer we estimate that >1.25x larger plastic capsules could be fielded in this platform with sufficient laser beam propagation to the waist of the hohlraum. We also estimate that a full scale plastic capsule, 1100 µm in capsule radius, would require ∼1-2 Angstroms of 1ω wavelength separation between the outer and inner beams to achieve a symmetric implosion in this platform.

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Section: 2mentioning

confidence: 99%