Impact of mass concentration variations on plasma dynamics in a laser-ablated CH target

Abstract Laser-produced plasmas in the field of inertial confinement fusion usually consist of multiple ion species with different atomic numbers and charge-to-mass ratios. With the presence of various plasma gradients, ion diffusion is driven, causing ion concentration to evolve and deviate from its initial value. In order to investigate the effect of ion diffusion on laser-produced plasmas, we implement an ion diffusion module within the radiation-hydro code MULTI-1D [ Comput. Phys. Commun. 203 226 (2016)]. Under the planar target geometry and simulation parameters considered in this study, ion species separation primarily occurs near ablation front and underdense region. Although ion diffusion just has a slight impact on plasma hydrodynamics such as density, temperature and pressure profiles, it could have significant influence on the processes in relevant to ion-acoustic wave, whose damping rate depends sensitively on ion concentration. It is found that the coupling factor of cross-beam energy transfer (CBET) could change a lot when ion diffusion is taken into account, indicating that ion diffusion could play important role in laser fusion.