斜入射激光等离子体堵口时空特性研究

在“星光II”上首次利用X光12分幅相机(XFC)成功地观测到了1.053 μm激光以45°方向斜入射孔靶和半腔靶等离子体堵口的时间和二维空间图象,获得了等离子体堵口速度,同时通过一维模型给出了斜入射条件下的等离子体堵口速度。实验结果表明：相同参数条件下半腔靶与孔靶相比,等离子体喷射速度高约15%。一维模型给出的等离子体喷射速度与XFC测出的等离子体喷射速度在实验误差范围内是一致的。     

核物理与等离子体物理学科研究进展

1脉冲功率技术及加速器物理 利用雪耙模型，对一个典型的微秒级导通时间等离子体断路开关物理过程进行了模拟计算，分析研究了导通物理机制和雪耙阵面的运动过程，获得了具有指导意义的数据和结果。在国内首次研制成功导通电流可达100kA的微秒导通时间等离子体断路开关，开展了等离子体枪与主回路之间的触发延时、等离子体枪数目及其工作电压对开关性能的影响规律实验研究，获得的典型数据和结果对开关的应用及等离子体源参数优化具有重要意义。     

X射线高空间分辨多色显微成像系统研制及应用

在激光间接驱动惯性约束聚变(ICF)领域中,获得具有极高空间分辨率(优于5μm)的X射线辐射图像,是研究烧蚀不稳定性、内爆流线等关键物理过程的数据基础。基于掠入射反射式成像原理的Kirkpatrick-Baez(KB)显微成像系统作为一种具有高空间分辨率和集光效率的X射线显微诊断设备,目前已成为国际ICF装置的X射线关键诊断设备。在神光Ⅱ和神光Ⅲ原型装置条件上开展了KB诊断技术及设备的研究,在KB系统的光学设计、光学元件和物镜与系统装调技术等方面取得了许多重要进展,研制了大视场KB、多色KB等高分辨率X射线显微成像系统。这些系统已应用于我国的ICF内爆芯部发光和流线测量、流体不稳定增长测量等实验中,为关键物理量的测量提供了高空间分辨率的清晰图像。     

斜入射激光等离子体堵口时空特性研究

 在“星光II”上首次利用X光12分幅相机(XFC)成功地观测到了1.053 μm激光以45°方向斜入射孔靶和半腔靶等离子体堵口的时间和二维空间图象，获得了等离子体堵口速度，同时通过一维模型给出了斜入射条件下的等离子体堵口速度。实验结果表明：相同参数条件下半腔靶与孔靶相比，等离子体喷射速度高约15%。一维模型给出的等离子体喷射速度与XFC测出的等离子体喷射速度在实验误差范围内是一致的。     

同步辐射在ICF研究中的应用

介绍同步辐射在ICF研究中的应用,对多种ICF实验诊断用软X光探测元器件及设备利用北京同步辐射装置(BSRF)-3W1B作能量响应绝对标定.首先采取透射光栅分光和软X光面陈CCD观测记录,对光源进行性能研究.在50—1500eV能区分7个能段,通过不同材料的前置滤片抑制高次谐波,获得单色性好于95%的单色光.采用美国IRD公司生产的AXUV-100硅光二极管作次级标准探测器.利用BSRL的反射率计靶室及其相关联动调束系统,获得连续可调的单色光标定束.在该束线上进行了多轮实验.获得大量探测器标定数据用于ICF实验研究,提高了实验精度.     

THEORETICAL CALCULATION OF THE RELATIVISTIC SUBCONFIGURATION-AVERAGED TRANSITION ENERGIES

A method for calculating the average energies of relativistic subconfigurations in highly ionized heavy atoms has been developed in the framework of the multiconfigurational Dirac－Fock theory. The method is then used to calculate the average transition energies of the spin-orbit-split 3d－4p transition of Co-like tungsten, the 3d－5f transition of Cu-like tantalum, and the 3d－5f transitions of Cu-like and Zn-like gold samples. The calculated results are in good agreement with those calculated with the relativistic parametric potential method and also with the experimental results.     

高Z元素类镍离子谱研究

用ＰＥＴ平晶谱仪测量了Ｈｆ,Ｔａ，Ｗ和Ｒｅ激光等离子体发射波长范围为５－８?的软Ｘ射线谱，重点研究了其类镍离子谱线，精确测量和准确辨认出四种高Ｚ元素的３７条ｎ＝３－４的类镍离子共振跃迁线和内壳层跃迁线。整个测量范围内谱线精确波长值的绝对误差小于０．００５?．与ＭＣＤＦ方法和ＨＦＲ方法得到的理论计算结果比较，两者符合相当好。 关键词：     

Analytical solution of crystal diffraction intensity

Plasma density and temperature can be diagnosed by x-ray line emission measurement with crystal, and bent crystals such as von Hamos and Hall structures are proposed to improve the diffraction brightness. In this study, a straightforward solution for the focusing schemes of flat and bent crystals is provided. Simulations with XOP code are performed to validate the analytical model, and good agreements are achieved. The von Hamos or multi-cone crystal can lead to several hundred times intensity enhancements for a 200μm plasma source. This model benefits the applications of the focusing bent crystals.     

An improved deconvolution method for X-ray coded imaging in inertial confinement fusion

In inertial confinement fusion （ICF）, X-ray coded imaging is considered as the most potential means to diagnose the compressed core. The traditional Richardson-Lucy （RL） method has a strong ability to deblur the image where the noise follows the Poisson distribution. However, it always suffers from over-fitting and noise amplification, especially when the signal-to-noise ratio of image is relatively low. In this paper, we propose an improved deconvolution method for X-ray coded imaging. We model the image data as a set of independent Gaussian distributions and derive the iterative solution with a maximum-likelihood scheme. The experimental results on X-ray coded imaging data demonstrate that this method is superior to the RL method in terms of anti-overfitting and noise suppression.     

Growth of deuterium clusters in a gas jet and ion energy spectrum of clusters in ultra-short laser field

Large deuterium clusters are generated using a cryogenic pulse valve with a cone nozzle (21 mm long, 4° open angle). Rayleigh scattering experiment is carried out to obtain the scaling relation between scattering signal SR and backing pressure P0. A method using the Coulomb explosion model is proposed to verify that the clusters continue to grow after their leaving the nozzle. Our experiments suggest a tentatively optimized position for laser cluster interaction.