Mitigation of cross-beam energy transfer in inertial-confinement-fusion plasmas with enhanced laser bandwidth

Abstract

Cross-beam energy transfer (CBET) is a significant energy-loss mechanism in directly driven inertial-confinement-fusion (ICF) targets. One strategy for mitigating CBET is to increase the bandwidth of the laser light, thereby disrupting the resonant three-wave interactions that underlie this nonlinear scattering process. Here, we report on numerical simulations performed with the wave-based code lpse that show a significant reduction in CBET for bandwidths of $2\phantom{\rule{0.16em}{0ex}}--\phantom{\rule{0.16em}{0ex}}5$ THz (corresponding to a normalized bandwidth of $0.2%\phantom{\rule{0.16em}{0ex}}--\phantom{\rule{0.16em}{0ex}}0.6%$ at a laser wavelength of $351\phantom{\rule{0.28em}{0ex}}\mathrm{nm}$) under realistic plasma conditions. Such bandwidths are beyond those available with current high-energy lasers used for ICF, but could be achieved using stimulated rotation Raman scattering in diatomic gases like nitrogen.