The 6th International Conference on Matter and Radiation at Extremes (ICMRE2023)

Even though tremendous progress has been made towards the realization of inertial confined fusion (ICF) ignition, for example, the recent achievement of 3.0MJ fusion energy yield at the National Ignition Facility in LLNL, the control of parametric instabilities in laser-plasma interactions remains a great challenge in this area. One of the proposed methods is to use a low-coherence light source as the drive laser, such as ultra-broadband lasers. Here, the stimulated Raman scattering (SRS) as one of the key parametric instabilities driven by a broadband laser propagating in homogeneous plasma is investigated theoretically and numerically in a multi-dimensional geometry. With increasing laser bandwidth, it is found that the sideward SRS gradually dominates over the backward SRS, indicating that a larger bandwidth is demanded for the suppression of sideward SRS [1]. Based on the current laser technology, we propose to generate a sunlight-like laser by combining two or more broadband beams with independent phase spectra. Using this kind of lasers, the bandwidth requirement for the inhibition of sideward SRS could be mitigated [2]. The findings not only provide new understanding of the  parametric instabilities driven by broadband lasers, but also could be useful for the design of ultra-broadband lasers as the next-generation ICF drivers.