激光等离子体参量不稳定（LPI）是阻碍惯性约束聚变（ICF）点火的关键因素之一，对其物理机制及抑制方案的研究有助于推进ICF及相关领域的发展。在ICF条件下，LPI呈现出多时空尺度和极端非线性等特征，很难被描述和控制。现阶段有非均匀脉冲链（STUD）等抑制方案提出，但仍只停留在理论阶段。申请人提出的宽带解耦激光有效抑制LPI的方案受到了国际同行的广泛关注。同时，我们提出了利用强激光在等离子体中通过自调制效应展宽频谱的方法，为产生大能量宽带光提供了备选方案。本项目将深入理解非均匀等离子体中LPI的饱和机制，以及在不同参数区间内的物理特征。以此为基础，建立宽带光激发LPI的广义模型，为非均匀等离子体中LPI的抑制及其非线性机制的认识提供参考。结合数值模拟我们将分析由等离子体调制产生的宽带光抑制LPI的参数条件及抑制效果。本项目将为ICF中激光等离子体相互作用的物理及控制方案研究提供有力的依据。

Parametric instabilities excited in the laser plasma interactions represent a critical obstacle to be solved in inertial confinement fusion (ICF). Studies about the physical mechanisms and inhibition schemes of parametric instabilities are helpful to promote the development of ICF and related fields. Parametric instability is extremely nonlinear and difficult to be controlled under ICF conditions. Several suppression schemes have been proposed, such as spike trains of uneven duration and delay (STUD). However, these schemes are still far from practical application. The decoupled broadband lasers proposed by the applicant have garnered much more attention from the international counterparts. Meanwhile, we have proposed a mechanism that a high power laser pulse can be self-modulated to a broad bandwidth over 100% after it passes through a tenuous plasma, which paves a way to experimentally demonstrate the suppression of laser plasma instabilities via multi-frequency broad bandwidth laser. This project will study the nonlinear saturation of parametric instabilities in inhomogeneous plasma, and analyze the characteristics of instabilities in different parameter ranges. Based on the thorough comprehension of parametric instabilities, we will study the general bandwidth suppression model via theoretical analysis, which is an important reference to parametric instability suppression and also the understanding of its nonlinear physical mechanism. The suppression effect of self-modulated broadband lasers on parametric instabilities will be identified via numerical simulation. Our research will offer reliable reference to the physical mechanism and controlling scheme of parametric instabilities in ICF.