平面调制靶瑞利-泰勒不稳定性初步研究

Preliminary experimental study of Rayleigh-Taylor instability of surface perturbation target

瑞利-泰勒不稳定性增长的准确估计是激光聚变的重要研究课题。在神光Ⅱ装置上,利用面向背光照相技术对正弦调制平面靶的瑞利-泰勒不稳定性增长进行了实验研究,得到了清晰的时空分辨图像;采用傅里叶变换取基模法和求波峰波谷差值法分析了实验结果;两种方法得到的靶扰动增长因子相同。实验中平面靶扰动增长较小可能是密度梯度致稳和烧蚀致稳抑制了扰动增长,也可能是扰动进入了非线性阶段而使增长不大。

An accurate evaluation of the growth rate of the Rayleigh-Taylor（RT）instability is a critical issue for inertial confinement fusion. This paper uses the face-on radiography technology to investigate the Rayleigh-Taylor instability of sine modulated surface target at the Shengguang Ⅱ facility and gains vivid space and time resolution images. The experimental results are analyzed by two methods, i. e. , figuring out fundamental mode Fourier coefficient and figuring ,out the D-value of wave crest and wave hollow. The two methods obtain the same perturbation growth factor. Moreover, this paper presents possible reasons for the little growth with a qualitative interpretation, i. e. , the density gradient stabilization and ablative stabilization suppress the perturbation growth, or the perturbation turns into the non linear stage, which causes the little growth.