等离子体界面附近激光场中的电子的运动

分析在等离子的两个不同密度区的交界面附近激光场中电子的运动,导出了电子横向动量与纵向动量的相互关系的一般方程,分析发现,介质的非均匀性导致电子运动特性的重要改变,在一定下,这种非均匀怀有利于注入电子获得加速。     

Compton散射下激光等离子体界面附近电子的运动

研究了多光子非线性Compton散射下等离子体中两个不同密度区的界面附近耦合激光场中电子的运动, 导出了电子的横向动量与纵向动量相互关系的一般方程.研究发现：介质的非均匀性导致电子运动特性的重要变化,在一定的条件下,这种非均匀性有利于注入电子获得加速;散射可有效地降低弹推阈值.当耦合脉冲强度低于弹推阈值时,电子最终被脉冲超过,但无论对初始时刻静止的电子还是运动的电子,能量增益均不为0,且随注入能量的提高而迅速地增加.当耦合脉冲强度高于弹推阈值时,电子最终超过脉冲而获得很高的能量增益,其值远远高于均匀等离子体的情况.在入射相同能量的情况下,耦合光会使电子获得更高的能量增益.     

磁控溅射镀膜过程中非均匀磁场中电子的运动

讨论了磁控溅射过程中电子在非均匀电磁场中的运动规律,分析了靶材非均匀溅射及磁控溅射基片温升低、溅射速率高的原因.     

考虑随机过程影响的径迹重建

对L3宇宙线实验中μ子事例的动量重建方法进行了研究.在事例的重建中,考虑了某些影响径迹重建精度的因素,如磁谱仪内部磁场的非均匀性和仪器自身物质对粒子的多次散射等过程引起的误差.经过修正后的μ子事例的动量分辨有了显著的改善.     

二氟甲烷分子3a1和2b2轨道的电子动量谱

借助电子动量谱学结合量子化学理论和其他方法可以给出轨道电子在整个空间的分布信息,由此给出电子运动的完备描述[1,2 ] .清华大学电子动量谱学实验室近几年已成功地对甲烷[3] 、异丁烷[4 ] 、环戊烷[5] 、二乙酰等[6 ] 分子的轨道电子动量分布进行了测量.我们利用第二代电子动量谱仪首次对CH2 F2 分子3a1和2b2 轨道的电子动量谱进行测量,并与理论计算结果作了比较.同时还计算了坐标空间和动量空间中电子在x - y平面的密度分布.电子动量谱学最基本的过程是(e ,2e)反应,即电子与靶粒子碰撞而发生的电离过程.而对于(e ,2e)反应,含有大量信…     

探测二茂铁外价轨道(e,2e)反应中的扭曲波效应

利用第三代高效率电子动量谱仪,分别在600和1500 eV两种不同入射电子能量下获得了二茂铁(ferrocene)分子外价轨道的电离能谱和电子动量谱的相关实验结果.并利用非相对论与标量相对论密度泛函方法计算出了二茂铁的重叠型和交错型两种不同构象的理论动量谱.两种构象的外价轨道一一对应,理论电子动量谱基本一样.对二茂铁的外价轨道,在低动量区观测到了强烈的扭曲波效应,这与这些轨道主要由铁原子的3d轨道构成有关.通过相对论和非相对论计算结果的比较,表明相对论效应对于二茂铁的外轨道动量分布几乎没有影响. 关键词： 二茂铁分子 电子动量谱 相对论效应 扭曲波效应     

Electron Momentum Spectroscopy of Ethanethiol Complete Valence Shell

利用(e,2e)电子动量谱学手段首次测量了乙硫醇分子全部价轨道的束缚能谱和电子动量分布. 谱仪采用非共面对称的运动学条件,入射电子能量为1.2 keV加束缚能. 实验结果与密度泛函和Hartree-Fock方法的理论计算结果基本相符. 在束缚能谱中,观察到了17.8 eV的可能的伴线,并用电子动量谱进行了研究和标识.     

正交双色场中氢分子非次序双电离的研究

利用经典系综模型,研究了正交双色场作用下氢分子非次序双电离中双电离电子的相关特性.结果表明,双电离电子相关动量谱强烈地依赖于正交双色场的相对相位.通过改变正交双色场的相对相位,相关动量可以从反相关模式转变为相关模式.向后分析表明,相关电子动量谱对双色场相对相位的依赖关系起源于碰撞过程中碰撞电子碰撞角和碰撞动量对相对相位...     

异二氯乙烯价壳层轨道电子结构的电子动量谱研究

本文报道了异二氯乙烯分子价壳层轨道电子结构的电子动量谱研究.实验由一台(e,2e)电子动量谱仪在非共面对称的几何条件下开展,入射电子能量为1200 eV.实验获得了异二氯乙烯价壳层各个轨道的电离能谱和电子动量分布.采用Hartree-Fock方法和密度泛函方法结果与实验数据基本一致.研究发现,干涉效应会对2a_2和5b_2这两个Cl孤对电子轨道的电子动量分布产生显著影响.     

异二氯乙烯价壳层轨道电子结构的电子动量谱研究（英文）

本文报道了异二氯乙烯分子价壳层轨道电子结构的电子动量谱研究.实验由一台(e,2e)电子动量谱仪在非共面对称的几何条件下开展,入射电子能量为1200 eV.实验获得了异二氯乙烯价壳层各个轨道的电离能谱和电子动量分布.采用Hartree-Fock方法和密度泛函方法结果与实验数据基本一致.研究发现,干涉效应会对2a_2和5b_2这两个Cl孤对电子轨道的电子动量分布产生显著影响.     

Ponderomotive nongradient force acting on a relativistic particle crossing an inhomogeneous electromagnetic wave

The ponderomotive force acting on a relativistic charged particle crossing an inhomogeneous electromagnetic wave is investigated numerically and analytically. The initial velocity of the particle is perpendicular to the electric field vector of the wave and to the direction of its propagation. The wave has zero gradient in the direction of propagation and is inhomogeneous in both transverse directions. It is shown that the ponderomotive force acting on the particle is parallel to the wave vector. The magnitude of the force is determined not only by the extent of wave inhomogeneity in the direction of the translational motion of particle, but also by its inhomogeneity in the transverse direction. It is found that the trajectory of a particle is determined by the action of ponderomotive forces as well as by its drift in a nonuniform field.     

Screening of collective cyclotron resonance in inversion layers on InSb

Cyclotron Resonance (CR) of inversion electrons on InSb is studied in parallel magnetic fields with normally incident light. Whereas in this Voigt configuration collective CR is observed in thin bulk samples, we observe single particle CR in the case of inversion layers. The apparent screening of the collective mode is explained by the inhomogeneity of the inversion electron gas in crossed electric and magnetic fields.     

Generation of energetic electrons and ions by interaction of relativistic laser pulses with a supercritical plasma

Generation of hot electrons and fast ions under the action of a relativistic femtosecond laser pulse propagating through a supercritical-density plasma is studied in terms of the kinetic theory by constructing propagators for plasma particle distribution functions. Calculations are carried out for different laser pulse intensities, different sorts of multicharged ions, and different degrees of plasma inhomogeneity. Mechanisms of electron and ion acceleration in the plasma are explored.     

无网格等离子体静电模粒子模拟方法

介绍了一种无网格粒子模拟方法:三维快速多极展开方法(3DFMM),对其进行改进以提高精度.在低维粒子模拟中,采用具有低维运动的球粒子模型.模拟了尘埃粒子在背景等离子体中产生的势场,以及等离子体中电子相对于离子运动所引起的不稳定性,并得到合理的物理图象.     

On the theory of nonlinear Thomson scattering of a highly focused laser pulse

The problem of nonlinear Thomson scattering of an ultrashort laser pulse on free electrons from a sharp focus is solved within the test particle approach. To describe the laser beam fields, an exact solution to the Helmholtz equation is used, which allows simulation of the electron dynamics and emission when the paraxial approximation is certainly inapplicable. Characteristics of attosecond electromagnetic pulses of secondary emission from test electrons during their motion near the laser focus are studied.     

PIC Simulation of the Motion of Plasma around Ion Sensitive Probes

The current‐voltage characteristics, the structure of electric potential around an ion sensitive probe and the particle flux on the ion collector have been simulated by the two dimensional particle‐in‐cell code (Berkeley Code). Concerning the separate mechanism of ions and electrons on the probe, the importance of electric potential profile around the electrode was pointed out. It was found that the E × B drift motion of electrons moving along the equipotential surface plays an essential role in the ISP measurement.     

Pauli’s Exclusion Principle in Spinor Coordinate Space

The Pauli exclusion principle is interpreted using a geometrical theory of electrons. Spin and spatial motion are described together in an eight dimensional spinor coordinate space. The field equation derives from the assumption of conformal waves. The Dirac wave function is a gradient of the scalar wave in spinor space. Electromagnetic and gravitational interactions are mediated by conformal transformations. An electron may be followed through a sequence of creation and annihilation processes. Two electrons are branches of a single particle. Each satisfies a Dirac equation, but together they are a solution of the curvature condition. As two so identified electrons approach each other, the exclusion principle develops from the boundary conditions in spinor space. The gradient motion does not allow the particles to overlap. Since the spinor-gradient of the scalar wave function is odd in the coordinates, the sign of the wave function must change at the electron-electron boundary. The exclusion principle becomes geometry intrinsic and all electrons are combined into one field. Further applications are proposed including the possibility of improved numerical calculations in atomic and molecular systems. There also may be extensions to nuclear or particle physics. Implications are expected for the properties of rotating objects in a gravitational field.     

Inhomogeneity tensors of ion microfield in Debye plasma at neutral emitter

A method of calculation of inhomogeneity microfield tensors in Debye plasma, using the Mayer-Mayer cluster expansion, is presented. The octupole inhomogeneity tensor of the ion microfield at a neutral emitter has been calculated for the first time. The quadrupole inhomogeneity tensor of the ion microfield at a neutral emitter has been recalculated. We have performed numerical calculations for plasma consisting of atoms, electrons and singly or doubly charged ions.     

Low-diffraction direct particle acceleration by a radially polarized laser beam

Two constants of the motion, which simplify the relativistic particle dynamics in a laser beam of radial polarization, are identified. Many-particle simulations based on the reduced set of equations of motion in a beam of relativistic intensity, demonstrate acceleration in vacuum to GeV energies of electrons, alpha particles and oxygen bare nuclei. The axially-injected particles are shown to be accelerated with negligible diffraction.     

Neutrino in matter and external fields

A technique for describing various processes proceeding in matter and involving neutrinos and electrons is discussed. This technique is based on “the method of exact solutions,” which implies the use of solutions to proper Dirac equations for particle wave functions in matter. Exact solutions for the neutrino and the electron in the cases of uniform nonmoving and rotating matter are discussed. On studying relativistic neutrino motion and associated neutrino-energy quantization in rotating matter, a semiclassical interpretation of particle finite motion is developed. In the general case of neutrino and electron motion in matter with varying parameters, the corresponding effective force acting on the particles is determined. The possibility of electromagnetic-wave radiation by an electron that moves in a dense neutrino flux of varying density and which is accelerated by this kind of force is predicted.