非全裸氟离子与氖原子碰撞中的转移电离研究

采用位置灵敏探测和散射离子 反冲离子飞行时间技术测量了强相互作用区F2 + 和F3 + 离子与Ne原子碰撞中的转移电离截面与单电子俘获截面之比 .与Fq+ He实验结果进行了比较 ,并进行了定性讨论. The ratios of the cross-section of the transfer ionization to the single electron capture of Neon induced by F 2+ and F 3+ ions are measured by means of the time-of-flight technologie. In the present energy range, the transfer ionization C1I1 of neon can be considered as a two-step process, in which one electron is captured by projectile and another one is directly ionized, and the transfer ionization C1I2 process should be considered as a subsequent rearrangement of neon following...     

中低能非全裸C离子与He原子的碰撞研究

采用反冲离子飞行时间-散射离子位置灵敏符合测量技术，测量了能量范围在0.7v₀—4.4v₀(v₀为玻尔速度)的碳离子C^q+(q=1—4)与He原子碰撞过程不同出射道靶原子的双电离与单电离截面比R，包括入射离子不损失电子(直接电离)的出射道(R_q,q),入射离子俘获一个电子的出射道(R_q,q-1)和入射离子损失一个电子的出射道(R_q,q+1)，并研究了R随入射C离子的能量及电荷态的变化关系.实验表明，对给定电荷态的入射离子，靶原子的双电离与单电离截面比R与出射道有很强的依赖关系，即R_q,q<R_q,q+1<R_q,q-1.直接电离出射道截面比R_q,q与入射离子电荷态几乎无关，而入射离子俘获一个电子的出射道和损失一个电子的出射道靶原子双电离与单电离截面比R_q,q-1和R_q,q+1却与入射离子电荷态有很强的关系.采用原子极化理论和电子屏蔽与反屏蔽作用对实验结果进行了解释. 关键词： 离子-原子碰撞 电离 截面比     

非全裸氟离子与氦原子碰撞中的转移电离过程

采用位置灵敏探测和散射离子 反冲离子飞行时间测量技术 ,测量了强相互作用区氟离子与氦原子碰撞中的转移电离截面与单电子俘获截面之比 .实验发现 ,该比值随作用强度的增加而减小 .在本工作能区 ,转移电离现象可视作一个电子被俘获、另一个电子被电离的两步过程 ;He原子二重电离的主要机制为两步机制. The cross-section ratios of the transfer ionization to the single electron capture of helium induced by fluorine ions in the strong-interaction region were measured by means of the position-sensitive-detecting and the time-of -flight (TOF) technologies. Is is found that the cross section ratios decrease with the increasing of the interaction-strength κ in this work. In the energy range of this work, the transfer ionization can be considered as a two-step process that one electron is captured by projectile...     

非全裸碳离子与氦原子碰撞过程中的多重电离研究

采用飞行时间符合技术测得１．５—７．５ＭｅＶ非全裸碳离子轰击氦原子，引起氦原子双重电离与单重电离的相对截面比。对碰撞过程进行多体经典轨道蒙特卡罗模拟，得到相应的Ｏｌｓｏｎ—Ｓｃｈｌａｃｈｔｅｒ曲线，结合本实验结果，给出非全裸碳离子引起氦原子双重电离和单重电离的绝对截面，并进行了讨论。     

Na离子和Cl离子引起He原子直接多重电离过程的研究

利用2～8 MeV的Naq+、Clq+(q=2,3,4,5)轰击氦原子,对碰撞的直接多重电离过程进行研究.实验采用反冲离子-散射离子飞行时间符合技术,通过反冲离子飞行时间谱区分不同价态反冲离子;利用静电偏转和位置灵敏探测技术区分不同电荷态散射离子;结合CAMAC-PC多参数获取系统得到一定价态散射离子所对应的反冲离子电荷态分布谱;经分析该谱得到直接多重电离截面与直接单电离截面之比R21.讨论了R21随入射离子速度和电荷态的变化关系.     

氦原子与非全裸氟离子碰撞过程中多重电离的研究

用飞行时间符合技术测量了１．５－７．５ＭｅＶ非全裸氟离子与氦原子碰撞引起的氦的双、单重电离相对截面比，对非全裸离子核外电子对碰撞过程的影响进行了讨论。对碰撞系统还进行了多体经典轨道蒙特－卡罗模拟，得到氦的双、单重电离绝对截面，并对结果进行了讨论     

等电荷态离子与He原子碰撞中的转移电离过程研究

采用位置灵敏探测和飞行时间技术测量了等电荷态离子C^q 、N^q 、O^q 、Ne^q (q=4，5，6，7)与He原子碰撞中，转移电离截面与单电子俘获截面的比值Ro研究了相同q入射的情况下，R与入射离子核电荷数Z的依赖关系。在统计蒸发模型的基础上对实验结果进行了解释。     

等电荷态离子与He原子碰撞中的转移电离过程研究

采用位置灵敏探测和飞行时间技术测量了等电荷态离子Cq+、Nq+、Oq+、Neq+(q=4,5,6,7)与He原子碰撞中,转移电离截面与单电子俘获截面的比值R.研究了相同q入射的情况下,R与入射离子核电荷数Z的依赖关系,在统计蒸发模型的基础上对实验结果进行了解释.     

类硼离子的电子碰撞电离截面

运用扭曲波玻恩交换近似对处于Hartree-Fock基态的类硼离子的电子碰撞直接电离截面进行了计算。电离过程中直接电离与交换电离振幅的干涉有重要的贡献。研究结果表明“自然相因子”近似比“最大干涉”近似要好。后者用于其它离子种类的计算与实验符合很好。同Moores等人的Coulomb-Born近似计算相比较,我们的计算结果与现有的实验数据符合有改进。 关键词：     

Electrons in a Nonideal Partially Degenerated Plasma with Multiple Ionization

We consider peculiarities in the behavior of free electrons in an extremely-dense hot plasma with multiple ionization and partial degeneration. In different ways, we exhibit the strong Coulomb coupling of electrons and ions in the behavior of low- and high-kinetic-energy electrons. As a result, a necessity arises to consider, along with classical fast Debye electrons, their complementary cellular group of electrons constantly interacting with central ions of cells. We discuss the distribution of free electrons between the two groups, along with the role of two-group effects, of a not point character of ions in electron-transfer processes, and the consequences of the X-ray emitting X-pinch hot spot for the plasma. The existence of the physical limits for X-pinch plasma compression is among those consequences.     

Double Electron Processes in Collisions of Partially Stripped Ions C^q＋ （q = 1-4） with Helium

The multi-electron processes are investigated for 17.9-120 keV/u C^1＋, 30-323 keV/u C^2＋, 120-438 keV/u ^C3＋, 287-480 keV/u C^4＋ incident on a helium target. The cross-section ratios of double electron （DE） process to the total of the single electron （SE） and the double electron process （i.e. SE＋DE）, the direct double electron （DDI） to the direct single ionization （DSI） as well as the contributions of DDI to DE and of TI to DE are measured using coincidence techniques. The energy and charge state dependences of the measured cross-section ratios are studied and discussed.     

Statistical Ionization Equilibrium in Partially Degenerate Plasmas

The thermal ionization equilibrium in plasmas is considered at pressures for which the electron gas is partially to considerably degenerate. An ionization equation is derived which takes into account that i) the electron energies are distributed according to Fermi statistics and ii) the (heavy) ions and atoms obey Boltzmann statistics which is valid up to pressures at which the wave functions of the atoms begin to overlap. A comparison of the quantum statistical and Saha ionization equations indicates that the degeneracy effects in the electron gas suppress somewhat the ionization. It is remarkable that the Saha equation describes, approximately, the thermal ionization equilibrium up to the critical pressure at which the wave functions of the atoms begin to overlap (e.g., up to P ~ 103 Bar and P ~ 106 Bar in the cases of Cs and H plasmas, respectively), although the electrons are noticeably degenerate.     

Nonlinear Characteristics of an Intense Laser Pulse Propagating in Partially Stripped Plasmas

The nonlinear optic characteristics of an intense laser pulse propagating in partially stripped plasmas are investigated analytically. The phase and group velocity of the laser pulse propagation as well as the three general expressions governing the nonlinear optic behavior, based on the photon number conservation, are obtained by considering the partially stripped plasma as a nonlinear optic medium. The numerical result shows that the presence of the bound electrons in partially stripped plasma can significantly change the propagating property of the intense laser pulse.     

Nonlinear Characteristics of an Intense Laser Pulse Propagating in Partially Stripped Plasmas

The nonlinear optic characteristics of an intense laser pulse propagating in partially stripped plasmas are investigated analytically. The phase and group velocity of the laser pulse propagation as well as the three general expressions governing the nonlinear optic behavior, based on the photon number conservation, are obtained by considering the partially stripped plasma as a nonlinear optic medium. The numerical result shows that the presence of the bound electrons in partially stripped plasma can significantly change the propagating property of the intense laser pulse.     

Ionization of Hydrogen and Helium Atoms in Collisions with Relativistic Structural Heavy Ions

Based on the eikonal approximation, cross sections for single and double ionization of hydrogen and helium atoms in collisions with structural multiply charged heavy ions moving with relativistic velocities are calculated. In the present paper, the structural ions are taken to mean the ions with partially filled electronic shells. It is demonstrated that a consideration of the ion charge extension may noticeably change the corresponding cross sections compared to the cross sections for ionization by point ions having the same charges and energies.