Parametric instabilities such as stimulated Raman scattering (SRS), stimulated Brillouin scattering (SBS) and two plasmon decay (TPD) are one of the most fascinating subjects in laser plasma physics. In particular, they may cause significant laser energy loss and produce harmful hot electrons to preheat fusion targets in laser-driven inertial confinement fusion (ICF). Therefore, the understanding and control of parametric instabilities are essential to the realization of laser fusion.
In this report, I will first briefly review the research background and basic physical process of the parametric instabilities. Then, our theoretical and numerical simulation results about the development of parametric instabilities in the interaction of broadband lasers with plasmas will be displayed and discussed with the latest experimental results [1,2]. Next, I will present an accurate mathematical model for describing broadband laser, and further generalize the model to describe sunlight-like laser with a certain bandwidth and random polarization. The mitigation of parametric instabilities using sunlight-like lasers will be discussed [3]. Finally, I will briefly discuss how to reduce the coherence of lasers by using plasma optical methods, such as the laser depolarization for the crossed laser beams in ICF [4].

[1] Z. Liu, H. H. Ma, W. Wang et al., Nuclear Fusion 63, 126010 (2023).
[2] X. F. Li, S. M. Weng, P. Gibbon et al., Matter and Radiation at Extremes 8, 065601 (2023).
[3] H. H. Ma, X. F. Li, S. M. Weng et al., Matter and Radiation at Extremes 6, 055902 (2021).
[4] Y. X. Wang, S. M. Weng, P. Li et al., High Power Laser Science and Engineering 11, e37 (2023).
 

inertial confinement fusion,parametric instabilities,broadband laser,plasma optics,stimulated Raman scattering