论文标题
研究兰登对SR从早期通货膨胀到二级不稳定性晚期发展的非线性演变的研究
Investigation of Langdon effect on the nonlinear evolution of SRS from the early-stage inflation to the late-stage development of secondary instabilities
论文作者
论文摘要
在激光辐射的等离子体中，兰登效应可以导致超高斯电子能量分布函数（EEDF），对刺激的向后拉曼散射（SRS）施加了重大影响。在这项工作中，通过三波模型模拟和Vlasov-Maxwell模拟对SRS非线性演变的影响，对高强度和低强度激光驱动器的等离子参数覆盖了0.19至0.48的等离子参数。在SRS进化的早期阶段，发现除了电子诱捕引起的动力学效应[phys。等离子体25，100702（2018）]，兰登效应还可以显着扩大SRS绝对生长的参数范围，并且绝对SR达到饱和的时间在某些参数区域内的Langdon效应大大缩短了饱和的时间。在SRS的后期，当次要不稳定性（例如电子等离子体波衰减到光束声模式，撤销和兰穆尔衰减不稳定性变得重要）时，Langdon效应会通过影响二次过程来影响SRS的反射率。兰登对非线性进化和SR饱和效果的理解将有助于更好地理解和预测惯性限制融合中的SRS。
In a laser-irradiated plasma, the Langdon effect can result in a super-Gaussian electron energy distribution function (EEDF), imposing significant influences on the stimulated backward Raman scattering (SRS). In this work, the influence of a super-Gaussian EEDF on the nonlinear evolution of SRS is investigated by three wave model simulation and Vlasov-Maxwell simulation for plasma parameters covering a wide range of kλDe from 0.19 to 0.48 at both high and low intensity laser drives. In the early-stage of SRS evolution, it is found that besides the kinetic effects due to electron trapping [Phys. Plasmas 25, 100702 (2018)], the Langdon effect can also significantly widen the parameter range for the absolute growth of SRS, and the time for the absolute SRS to reach saturation is greatly shorten by Langdon effect within certain parameter region. In the late-stage of SRS, when secondary instabilities such as decay of the electron plasma wave to beam acoustic modes, rescattering, and Langmuir decay instability become important, the Langdon effect can influence the reflectivity of SRS by affecting the secondary processes. The comprehension of Langdon effect on nonlinear evolution and saturation of SRS would contribute to a better understanding and prediction of SRS in inertial confinement fusion.
