Ray-based modeling of cross-beam energy transfer between broadband lasers*

Broadband laser drivers (>1% relative bandwidth) have the potential to mitigate many of the laser plasma instabilities that limit the performance of current direct-drive inertial confinement fusion implosions.  To make a quantitative assessment of the impact of bandwidth, laser bandwidth models need to be included in the radiation hydrodynamic codes that are used to simulate implosions.  Two different approaches to broadband ray-based cross-beam energy transfer (CBET) modeling (discrete and fixed spectrum) are developed and shown to be in good agreement with wave-based calculations.