159 / 2025-03-15 22:44:34

Study on Kinetic Effects in Cross-Beam Energy Transfer

CBET,IAW,Landau damping

In laser-driven inertial confinement fusion (ICF), the cross-beam energy transfer (CBET) leads to significant energy redistribution between laser beams, which severely affects the compression symmetry of the capsule, causes laser energy loss, and reduces compression efficiency. Complex nonlinear kinetic processes, such as ion trapping and ion heating, often accompany  CBET process, making it challenging to accurately describe CBET intensity. Using particle-in-cell (PIC) simulations combined with theoretical analysis, we systematically investigate the variation of CBET intensity under different degrees of nonlinear effects across a range of laser and plasma conditions relevant to ICF parameters. First, a fast calculation method for linear CBET intensity has been developed and its accuracy verified against numerical simulation results. Subsequently, by comparing the PIC simulation results, which naturally include nonlinear effects, with the linear calculation results, we find that nonlinear effects consistently reduce CBET intensity in single-component He plasmas. However, in two-component CH plasmas, nonlinear effects can anomalously enhance CBET intensity within certain parameter ranges.We identified that this anomalous behavior results from defferent levels of trapping effects of hydrogen and carbon ions. Based on this understanding, we developed a model to approximate the Landau damping rate that qualitatively captures the characteristics of this anomalous CBET intensity variations.