Coupling nonlinear CBET effects to radiation-hydrodynamic modeling of ICF/HED experiments via laser ray tracing

CBET is an important energy redistribution mechanism in direct drive and indirect drive ICF/HED experiments performed on large-scale laser facilities. In order to model these experiments accurately, it is essential to include feedback from the laser-plasma instabilities on hydrodynamics. Nonlinear effects can cause CBET gain to deviate from linear theory predictions typically used in laser ray tracing codes. In this work, we developed a new CBET formulation in Mazinisin [1], a laser ray-tracing code developed by LLE, that includes effects of saturation in a physics-based nonlinear model and evolving plasma conditions from simulations using the LANL Eulerian radiation hydrodynamics code xRAGE. We performed simulations to test the implementation of the nonlinear CBET model using settings and results from experiments [2] at the LLE OMEGA laser facility. These experiments observe CBET saturation due to ion heating, which is not represented in a time-dependent manner by the linear model alone. We will compare results from linear and nonlinear CBET models and discuss the conditions necessary for improving the agreement between simulations and experiments. LA-UR-22-25814

[1] Marozas et al., Phys. Plasmas 25, 056314 (2018).

[2] A. M. Hansen, et al., Phys. Rev. Lett. 126, 075002 (2021).