Inertial Confinement Fusion

Abstract

It is well known that at typical inertial confinement fusion (ICF) laser intensities, cross-beam energy transfer (CBET)1 can cause significant laser energy losses to directly driven inertial confinement implosions. When CBET occurs, incoming laser light from one beam interacts with refracted, outgoing light from other beams, stealing some energy from the incoming light and scattering that energy away from the target along the path of the outgoing light rays. The result is a decrease in the ablation pressure, implosion velocity, and compression of the capsule, leading to lower fusion yield. One-dimensional simulations of direct-drive implosions at LLE have for years included CBET physics to better model implosions. However, because of the computational expense of including CBET physics in multidimensional simulations, these have often used a simpler, flux-limited Spitzer–Härm thermal transport method, where the flux limiter is variable in time and chosen to match the observables of more-detailed 1-D simulations, which include the nonlocal thermal transport (NLTT) and CBET physics. Because of this, few studies have been performed that include the effects of CBET on the symmetry of direct-drive ICF implosions.