【作者】 赵阳；

【导师】 刘劲松； 杨家敏；

【作者基本信息】 华中科技大学 ， 物理电子学， 2009， 博士

【摘要】 在惯性约束核聚变的研究中，辐射不透明度是等离子体模拟中的一个重要物理参数，需要精确的理论计算与实验测量；对于极端等离子体条件下的温度密度测量，需要借助于X射线光谱诊断法这一有利工具。本论文在不透明度实验中发展了时间空间分辨的测量技术，获得可靠的高分辨透过率谱，并与细致谱线计算结果进行了比较。对等离子体状态诊断中的X射线谱诊断法进行了深入的理论与实验研究。本论文的主要内容归纳如下：(1)对平面晶体谱仪的谱线波长定标方法进行了研究，发展了传统的辅助光阑法，即利用谱线曲率法得到晶体与成像面的夹角；提出了一种利用谱线曲率直接测量谱线波长的新方法，并从实验与理论上进行了分析。在北京同步辐射3W1B装置上完成了1keV～1．5keV的X光胶片绝对响应曲线的标定工作，为不透明度实验测量提供了定量测量。(2)在神光Ⅱ装置上的不透明度实验中，采用点投影背光法测量了铝等离子体的透过率谱。通过采用三明治半样品靶实现了空间分辨测量，在一次打靶中获得了背光源谱，样品自发射谱，透射谱的信息，减小了由于实验发次之间的波动引起的不确定度，提高了数据获取的合理性。通过9路短脉冲打靶得到200ps的短X-ray背光实现了高时间分辨测量，在短脉冲持续时间内获得了均一的样品状态，便于与确定温度密度状态下的理论模型进行比较。设计了侧面背光法测量膨胀Al样品的厚度以及密度，将实验结果与流体力学模拟进行了比较。(3)建立了将能级布居计算(激发与自发辐射等快过程)和离化度分布计算(离化与复合等慢过程)分离的稳态碰撞辐射模型。研究了非局域热动平衡等离子体的发射谱，并对铝激光等离子体的发射光谱进行了模拟。(4)等离子体状态诊断是ICF研究中的重要课题。基于神光Ⅱ激光装置的不透明度实验，建立了利用Fe等离子体L吸收边的移动量来诊断等离子体密度的理论方法。在星光装置上通过晶体谱仪狭缝成像得到时间积分空间分辨的非平衡激光铝等离子体的K壳层自发射谱，通过之前建立的稳态碰撞辐射模型，给出了级间共振线强比He-α／Ly-α与电子温度的函数关系，并通过拟合共振线与伴线混合的实验测量谱，分离出了1s-2p共振线的真实强度，提高了电子温度诊断的精度。更多还原

【Abstract】 Radiative opacity is a significant physical parameter in plasma simulation for theresearch on the inertial confinement fusion(ICF),and it requires precise theoreticalcalculation and experimental measurement.X-ray spectrum diagnosis is a powerful tool tocarry out the measurement of plasma temperature and density in extreme plasma condition.In this paper,space-and time-resolving measurements are developed to achieve reliablehigh resolution transmission spectrum,and it has been compared with the calculationresults of a detailed level accounting opacity code.In filed of plasma diagnostics themethod of X-ray spectrum diagnosis is studied in details both experimentally andtheoretically.The following is the main contents of the present paper:(1)The wavelength determination method of X-ray spectral line with planar crystalspectrometer is studied,the curvature of spectral line was used to determine the anglebetween crystal and recording plane in order to develop the auxiliary diaphragm method.And a novel method of directly wavelength determination by using the curvature of spectralline is proposed and it is analyzed both experimentally and theoretically.Calibration ofabsolute response curves between 1.0keV and 1.5keV for X-ray film is accomplished onBeijing synchrotron radiation 3W1B facility,and it can provide quantitative measurementin opacity experiment.(2)The point-projection method is adopted to measure the transmission spectrum inopacity experiment on ShenguangⅡlaser facility.A half sample sandwich target has beendesigned to perform space-resolved measurement.Simultaneous measurements of theself-emission spectrum,the backlighting source spectrum and the transmission spectrum inone shot,can reduce the experimental uncertainties from shot-to-shot fluctuation andachieve reasonable data.Short backlighter generated by the ninth laser beam has been usedto provide temporal resolution and absorption measurement in a unitary plasma state and itis helpful to make comparison between experimental transmission spectrum and theoreticalmodel at a certain temperature and density.Side-on imaging technique is applied tomeasure the thickness of the expanded A1 plasma layer and the density,and the result arecompared with the hydrodynamic simulations(3)A steady collisional-radiative model(CRM),which separates the set of equations for a determination of excited level populations(considering fast processes of excitationand spontaneous radiative transitions)and for calculation of ion concentrations(slowprocesses of ionization and recombination),is established.Emission spectrum under nonlocal thermal equilibrium is studied,and the X-ray spectra emitted from laser-produced A1plasma are modeled.(4)Plasma state diagnostics is a significant subject in the research of ICF.Based onthe opacity experiment on ShenguangⅡfacility,theoretical method of plasma densitydiagnostics by using shift of the L edge is established.On Xingguang facility,the nonequilibrium K-shell emission spectra of laser-produced A1 plasma are measured by thespace-resolved spectrometer,which is constructed by a flat crystal spectrometer with slit.By using the established steady collisional-radiative model,the interstage line intensityratio of He-α/Ly-αis given as a function of electron temperature.The real intensity of1s-2p resonance line is decomposed by fitting experimental spectra with the satellites andparent resonance line,and the precision of temperature diagnostics is improved.更多还原