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Xe、Gd、Dy和Au激光等离子体的双电子复合过程研究

Dielectronic Recombination Process in Laser Produced Plasmas of (Xe,Gd,Dy,Au)

【作者】 焦荣珍

【导师】 杨向东;

【作者基本信息】 四川大学 , 原子与分子物理, 2002, 博士

【摘要】 双电子复合(dielectronic recombination,DR)是一个重要的电子—离子碰撞过程,在中高温(0.1keV~10kev)和低密度(ne<1018cm-3)的天体和实验室等离子体中,它对建立和维持电离平衡及离子的激发态分布起着主要作用,因此对其光谱和双电子复合的研究是当前原子分子物理学科的前沿,在惯性约束聚变、X光激光和等离子体的诊断等领域有广阔的应用背景,尤其是用伴线强度比进行等离子体电子温度的诊断具有很好的实用性。本文在SOSA模型下,用自编的双电子复合速率系数程序(涉及到的Slater积分由Cowan程序包得出),系统地计算了Ni-like、Cu-like、Zn-like的Xe、Gd、Dy、Au激光等离子体的总双电子复合速率系数及态—态的双电子复合速率系数随电子温度的变化,并给出了相关的自电离系数Aa、辐射衰减系数Ar、电离势E和双电子伴线强度比;分析了影响双电子复合的主要因素,Aa、Ar随主量子数、旁观电子的变化规律及双电子伴线强度比随电子温度的变化。以上工作在目前尚未见相关文献报导,因此,本文的研究内容不仅填补了高Z元素的原子数据,而且对等离子体温度的诊断有一定的理论意义。 同时,在SOSA模型下,计算了双电子复合过程中的相关跃迁子阵的光谱特征参数(波长、半宽度、阵的相对强度),结合实验,以Au为例,具体分析了金的M带谱的特性、3d-5f跃迁的光谱特性、考虑双电子复合后的3d-4f跃迁的光谱特性、子阵的相对强度比与电子温度的关系,这为光谱的诊断提供了 四川大学博士学位论文更多的理论数据;为适应识谱的需要,在非局域热动平衡则On-LTE)下,先用类氢近似,计算得出电子密度分另为11-*1.oxl020cm-3、60xl02’cm-3、14义10ilo *-310X1022Cm”3和 17X102、m”3的条件下的三体复合、辐射复合、双电子复合系数随电子温度的变化,得出总的复合系数随电子温度的变化;结合相关的电离系数得出相应的离子占有数的比,最后,计算出一定电子密度和温度条件下,金等离子体的Co一like、Ni-like、Cu一like、Zn自like、GUlike的离子丰度,从而得至金等离子体在不同电子密度和温度条件下的平均荷态分配数,这填写了国内在非局域热动平衡仰on-LTE)下,计算金等离子体不同电子密度和温度条件下离子丰度和平均荷态分配数的空白。

【Abstract】 The dielectronic recombination (DR) is a main process in the course of electron-ion collision. At moderate (high) electron temperature and low (moderate) -electron density, it is dominant in keeping the balance of ionization and population of upper configuration ions. The paper gives the results of the total DR coefficients of Ni-like, Cu-like, Zn-like in the laser produced plasmas for (Xe,Gd,Dy,Au) and the DR rate coefficients of state-to-state with the change of electron temperature , as well as the relative auto-ionization rate coefficients Aa, radiative decay rate coefficients Ar, potential of ionization , intensity ratio of dielctronic satellite in the model (spin-orbit -split Array, SOSA). We analyze the main factor which effect DR coefficients with the. change of electron temperature and the rule which Ar and Aa change with the principal quantum numbers and spectator electrons. They are useful paramaters in the research of high-Z materials of laser- produced plasmas.At the same time, we calculate the charactical paramaters (Wave-length, FWHM, intensity of array) of the transition sub-array which is included in the process of dielectronic recombination. For example Au plasmas, M-band spectum, intensity of sub-ayyay, 3d-4f and 3d-5f transitions array of Au are analyzed comparing with experiment. These may provide a great number of atomic structure paramaters. For the necessary of obersving spectrum, the three-body recombination,radiative recombination and dielectronic recombination coefficients are calculated in some range of electron density(ne=1.0x1020cm-3,6.0xl020cm-3,1.4xl021cm-3, 1.0xl022cm-3andl.7xl022cm-3) with the change of electron temperature in the ( non-local-thermodynamic-equilibrium,Non-LTE) model at the condition of H-like approximation. The total recombination coefficients are calculated with the change of electron temperature. Making use of the ratio of the relavant population of ionization stage, the fractional population of ionization stage is calculated with the change of electron temperature. At last, the charge -state distribution for gold (Au) plasmas at some electron temperature and some electron density is calculated. It is very important for diagnosing the plasmas of Au in the laboratory.

  • 【网络出版投稿人】 四川大学
  • 【网络出版年期】2002年 02期
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