双电子复合过程在激光在Au靶耦合物理中的作用

 描述了考虑双电子复合过程的平均原子模型,通过与流体力学耦合计算,对双电子复合过程在激光－Au靶耦合物理中的作用进行了总体计算,结果表明,双电子复合对等离子体状态及X光转换等有明显影响,特别表现在晕区电子温度、电离度的降低,激光－X光的转换效率的提高以及X光的发光区域变宽等。     

双电子复合过程在激光在Au靶耦合物理中的作用

描述了考虑双电子复合过程的平均原子模型,通过与流体力学耦合计算,对双电子复合过程在激光－Au靶耦合物理中的作用进行了总体计算,结果表明,双电子复合对等离子体状态及X光转换等有明显影响,特别表现在晕区电子温度、电离度的降低,激光－X光的转换效率的提高以及X光的发光区域变宽等。     

金激光等离子体冕区电离态特性研究

提出一种测量金激光等离子体电荷态分布与平均电离度的X射线光谱学诊断方法。该方法基于稳态碰撞-辐射近似,考虑电子离子直接碰撞激发与双电子复合两种激发态布居方式,建立了金M带5f-3d跃迁组辐射总强度与离子态分布的耦合方程。根据实验测量的金平面靶激光等离子体冕区辐射的5f-3d跃迁线系的强度分布,诊断得到了金激光等离子体的电荷态分布与平均电离度。此外,还分析了电子温度、电子密度以及双电子复合过程对电荷态分布及平均电离度诊断的影响,并将实验诊断结果与辐射流体力学理论模拟结果及离化平衡动力学计算结果进行了对比分析。结果表明：实验诊断结果与基于CRE近似的离化平衡动力学计算结果近似;当电子温度高于1.5 keV时,双电子复合过程对电离度的诊断结果影响较小。     

金激光等离子体冕区电离态特性研究

 提出一种测量金激光等离子体电荷态分布与平均电离度的X射线光谱学诊断方法。该方法基于稳态碰撞-辐射近似,考虑电子离子直接碰撞激发与双电子复合两种激发态布居方式,建立了金M带5f-3d跃迁组辐射总强度与离子态分布的耦合方程。根据实验测量的金平面靶激光等离子体冕区辐射的5f-3d跃迁线系的强度分布,诊断得到了金激光等离子体的电荷态分布与平均电离度。此外,还分析了电子温度、电子密度以及双电子复合过程对电荷态分布及平均电离度诊断的影响,并将实验诊断结果与辐射流体力学理论模拟结果及离化平衡动力学计算结果进行了对比分析。结果表明：实验诊断结果与基于CRE近似的离化平衡动力学计算结果近似;当电子温度高于1.5 keV时,双电子复合过程对电离度的诊断结果影响较小。     

类氢类氦类锂镁离子双电子复合的旁观电子角动量研究

类氢类氦类锂镁离子经中间双激发态进行的双电子复合过程在研究惯性约束聚变电子温度中占有很重要的地位.用准相对论方法计算了双电子复合经不同Rydberg态跃迁通道的复合速率系数,并给出不同离化度离子的双电子复合速率系数随电子温度的变化规律.显示出离子的相关能对峰值的电子温度有很大影响,当类氢离子跃迁通道的旁观电子角动量为1时双电子复合系数最大,而类锂离子是旁观电子角动量为3时最大. 关键词： 双电子复合 镁离子 角动量     

Ca和Sr原子n′dnl自电离态在低电场中的线性Stark效应

用激光多步激发技术观察了Ca和Sr原子n′dnl双电子激发自电离态的电场效应。Stark光谱显示,在F<1/3n⁵的低电场中,Stark能级分裂与外电场强度线性相关。也观察了近简并l亚能级的Stark混合使自电离共振谱线在外电场中的增宽。这一效应在高温等离子体中对双电子复合速率的增加起重要作用。 关键词：     

电子碰撞激发机制中自电离与双电子俘获

 以Ge为例，研究了双电子复合代替自电离与双电子俘获对离子布居的影响；通过解包括双激发态和自电离与双电子俘获过程的速率方程组，研究了类F离子与类Ne离子基态对19.6nm与23.6nm激光线上、下能级的布居贡献因子及类Na离子与类Ne离子的电离速率，并讨论了这两条激光线的反转与增益。     

电子碰撞激发机制中自电离与双电子俘获

以Ge为例,研究了双电子复合代替自电离与双电子俘获对离子布居的影响;通过解包括双激发态和自电离与双电子俘获过程的速率方程组,研究了类F离子与类Ne离子基态对19.6nm与23.6nm激光线上、下能级的布居贡献因子及类Na离子与类Ne离子的电离速率,并讨论了这两条激光线的反转与增益。     

Evidence for strong Breit interaction in dielectronic recombination of highly charged heavy ions

Resonant strengths have been measured for dielectronic recombination of Li-like iodine, holmium, and bismuth using an electron beam ion trap. By observing the atomic number dependence of the state-resolved resonant strength, clear experimental evidence has been obtained that the importance of the generalized Breit interaction (GBI) effect on dielectronic recombination increases as the atomic number increases. In particular, it has been shown that the GBI effect is exceptionally strong for the recombination through the resonant state [1s2s(2)2p(1/2)](1).     

Observation of trielectronic recombination in Be-like Cl ions

Recombination involving the core excitation of two electrons, which may be termed trielectronic recombination, has been experimentally identified for the first time. Using Cl13+ ions circulating in the TSR heavy-ion storage ring, we have observed surprisingly strong low-energy trielectronic recombination resonances, comparable to the dielectronic process. At higher electron-ion collision energies, trielectronic recombination is suppressed due to the autoionization of the triply excited intermediate state into excited final states. The formation of the intermediate state depends sensitively on configuration mixing, making trielectronic recombination a challenge to atomic-structure calculations.     

类He的Y离子双电子复合计算

采用准相对论的多组态Hartree-Fock(HFR)方法计算了类Li的Y离子(Z=39)的能级和振子强度,并且通过采用扭曲波方法计算自由电子的波函数,我们得到了由类He的基态到类Li的双激发态的自电离几率和双电子复合系数。在计算中,相对论质量—速度和Darwin修正都包含在哈密顿中。为了便于等离子体细致能级占据数密度的动力学计算,我们用一个解析表达式来表示作为自由电子温度函数的双电子复合速率系数,这个表达式精确地描写了从类He的基态到类Li的单激发态的双电子复合。     

类铍钛离子态-态双电子复合速率研究

 研究了类铍Ti¹⁸⁺离子三类态-态双电子复合过程,基于多组态准相对率自洽场方法和扭曲波方法,计算了该离子在电子温度 0.01~1.0keV范围内的态-态双电子复合速率系数,并讨论了它们随电子温度、复合类型和上下能态的变化。     

类铍钛离子态-态双电子复合速率研究

研究了类铍Ti18+离子三类态-态双电子复合过程,基于多组态准相对率自洽场方法和扭曲波方法,计算了该离子在电子温度 0.01~1.0keV范围内的态-态双电子复合速率系数,并讨论了它们随电子温度、复合类型和上下能态的变化。     

X-ray spectra from highly ionized dense plasmas produced by ultrashort laser pulses

Hydrogen-like and helium-like X-ray spectra (between 7.1 and 8.2 , i.e., 1500 to 17.50 eV, respectively) from solid aluminium targets irradiated with high intensity (up to 10¹⁷ W/cm²) subpicosecond (0.7 ps) laser pulses have been measured. The spectra show that the resonance lines are very broad and very asymmetric. Evidence for a Doppler-shifted reabsorption of the resonance line emission has been found. The spectra have been simulated by a computer code for the calculation of spectral-line intensities and linewidths. Electron densities exceeding the critical density have been estimated for different laser intensities by comparing the observed and simulated intensity ratio of different dielectronic satellite lines. From the X-ray spectra generated byp- ands-polarized radiation fat different laser intensities, the thresholds for the formation of hydrogen-like and helium-like ions have been determined.     

Radiative cooling of tokamak plasmas due to multiply-charged Fe impurity ions

Calculations are presented for the rates of radiative energy loss from tokamak plasmas arising from radiation processes involving collisions between electrons and multiply-charged Fe impurity ions. The distribution of ionization states is determined from the steady-state corona model. The inclusion of dielectronic recombination raises the temperature at which each ion has its maximum equilibrium abundance. For certain nonhydrogenic ions, the dielectronic recombination rates obtained from previous calculations are found to be overestimated due to the neglect of autoionization into an excited state of the recombining ion. Electron impact excitation of resonance line radiation in the far ultraviolet and X-ray regions is the dominant radiative cooling mechanism at temperatures where ions with bound electrons are abundant. However, the radiation emitted during dielectronic recombination can be more important than direct recombination radiation and bremsstrahlung.     

Statistical dielectronic recombination rates for multielectron ions in plasma

We describe the general analytic derivation of the dielectronic recombination (DR) rate coefficient for multielectron ions in a plasma based on the statistical theory of an atom in terms of the spatial distribution of the atomic electron density. The dielectronic recombination rates for complex multielectron tungsten ions are calculated numerically in a wide range of variation of the plasma temperature, which is important for modern nuclear fusion studies. The results of statistical theory are compared with the data obtained using level-by-level codes ADPAK, FAC, HULLAC, and experimental results. We consider different statistical DR models based on the Thomas–Fermi distribution, viz., integral and differential with respect to the orbital angular momenta of the ion core and the trapped electron, as well as the Rost model, which is an analog of the Frank–Condon model as applied to atomic structures. In view of its universality and relative simplicity, the statistical approach can be used for obtaining express estimates of the dielectronic recombination rate coefficients in complex calculations of the parameters of the thermonuclear plasmas. The application of statistical methods also provides information for the dielectronic recombination rates with much smaller computer time expenditures as compared to available level-by-level codes.     

镁铝类氢类氦类锂离子双电子复合速率研究

 镁铝类氢类氦类锂离子经中间双激发态进行的双电子复合过程在用双示踪元素谱线强度比研究ICF电子温度中占有很重要的地位。计算了双电子复合经不同Rydberg态跃迁通道的复合速率系数，并给出不同离化度的总的双电子复合速率系数的变化规律，比较了它们在不同电子温度和不同跃迁通道的异同，对研究X射线激光、等离子体温度诊断等诸多应用领域提供了有价值的原子数据。     

类氖-锗电子碰撞激发X光激光的增益特性

 电子碰撞激发X光激光的增益特性依赖于电子密度Ne、电子温度Te、增益区宽度D R和介质速度梯度dv/dz等四个表征等离子体内部状态的参数。以类氖-锗离子为例研究了反转和增益特性对Te、Ne的依赖关系，并在典型的增益区宽度（D R=100 μm）和介质速度梯度（dv/dz=1.3×10⁹s^-1）下讨论了共振线俘获对增益特性影响，给出波长为19.6nm, 23.2nm和23.6nm三条激光线的增益目标区域。还讨论了双电子复合过程对离子布居的重要影响。     

类氖-锗电子碰撞激发X光激光的增益特性

电子碰撞激发X光激光的增益特性依赖于电子密度Ne、电子温度Te、增益区宽度D R和介质速度梯度dv/dz等四个表征等离子体内部状态的参数。以类氖-锗离子为例研究了反转和增益特性对Te、Ne的依赖关系,并在典型的增益区宽度（D R=100 μm）和介质速度梯度（dv/dz=1.3×109s-1）下讨论了共振线俘获对增益特性影响,给出波长为19.6nm, 23.2nm和23.6nm三条激光线的增益目标区域。还讨论了双电子复合过程对离子布居的重要影响。     

Influence of Debye Plasma on the KLL Dielectronic Recombination of H-Like Helium Ions

Using the Debye shielding model, the effects of plasma shielding on the dielectronic recombination processes of the H-like helium ions are investigated.It is found that plasma shielding causes a remarkable change in the Auger decay rate of the doubly excited 2p~2 ~3P_2 state.As a result,the dielectronic recombination cross sections from the doubly excited 2p~2 ~3p_2 state increases with the decreasing Debye shielding length.