Isolating the role of ion trapping in the saturation of cross-beam energy transfer*

Cross-beam energy transfer (CBET) induces an energy exchange between two crossing laser beams through the mediation of an ion acoustic wave, and this instability has been shown to significantly alter the implosion symmetry in inertial fusion experiments. Our limited understanding of the saturation and evolution of this instability, however, constrains our ability to accurately account for its effects in our implosion simulations. Here we take advantage of the kinetic physics captured in VPIC simulations to examine the role of ion trapping in the saturation of CBET in multi-speckled laser beams. In particular, we vary the overlapping beam intensity to characterize how the trapping effects change as we transition to the higher intensities where we observe the generation of hot electrons from forward stimulated Raman scattering (FSRS).