Three-Dimensional Reconstruction of Inertial Confinement Fusion Hot-Spot Plasma from X-Ray and Nuclear Diagnostics on OMEGA

Multidimensional effects limit the neutron yield and the compressed areal density of laser-direct drive-inertial confinement fusion implosions on the OMEGA Laser System with layered deuterium–tritium cryogenic targets. Low-mode asymmetry studies have concentrated on the reduced performance caused by an increasing mode-1 amplitude perturbation, [1,2] but the effect from the mode-2 perturbations requires a closer examination. A comprehensive 3D reconstruction technique to infer hot-spot and shell conditions at stagnation from four x-ray and nine neutron detectors distributed around the target chamber will be presented. Neutron diagnostics, providing measurements of the neutron yield, hot-spot flow velocity, and ion-temperature distribution, are used to infer the mode-1 perturbation at stagnation. The x-ray imagers record the shape of the hot-spot plasma to diagnose mode-1 and mode-2 perturbations. [3] A deep-learning convolutional neural network [4] trained on an extensive set of 3D radiation-hydrodynamic simulations [5] is used to interpret the x-ray and nuclear measurements to infer the 3D plasma profiles of the hot spot. Three-dimensional reconstructions of implosions are used to infer the amount of laser energy coupled to the hot-spot plasma and the perturbations to the plasma profiles caused by low-mode asymmetries. The dependence of the hot-spot flow velocity, ion temperature asymmetry, and neutron yield on low-mode asymmetries is derived from a parametric study of the 3D simulation database. This material is based upon work supported by the Department of Energy [National Nuclear Security Administration] University of Rochester “National Inertial Confinement Fusion Program” under Award Number(s) DE-NA0004144.

 

Collaborators: K.M. Woo, W. Theobald, R. Betti, L. Ceurvorst, C.J. Forrest, V. Gopalaswamy, P.V. Heuer, S.T. Ivancic, J.P. Knauer, A. Lees, M. Michalko, M.J. Rosenberg, R.C. Shah, C. Stoeckl, C.A. Thomas, and S.P. Regan

 

[1] O. M. Mannion et al., Phys. Plasmas 28, 042701 (2021).

[2] A. Lees et al., Phys. Rev. Lett. 127, 105001 (2021).

[3] K. Churnetski et al., High Energy Density Phys. 52, 101108 (2024).

[4] K. M. Woo et al., Bull. Am. Phys. Soc., UP11.00116 (2023).

[5] K. M. Woo et al., Phys. Plasmas 29, 082705 (2022).