高温稠密等离子体电子离子直接碰撞电离截面的理论研究

在高温稠密等离子体内，由于电子的热运动，产生了各种电子一离子碰撞过程，其中电子-离子直接碰撞电离就是一种很重要的物理过程。电子离子碰撞调节了等离子体内电子的布局数，使之从非平衡走向平衡。电子-离子的碰撞激发、离化导致电子在能级之间发生跃迁，影响能级的寿命，导致能级增宽，因而使谱线变宽，这种效应对研究等离子体辐射不透明度DTA(Detailed Term Accounting)模型具有重要的意义。

Ion-Pair Dissociations of Br CN by Electron Impacts

Ion-pair dissociation is an important molecular process and frequently happens when the target molecule is pumped to its electronically superexcited states. In contrast to the experimental studies of photoexcitation ion-pair dissociation, there are some experimental challenges in the electron-impact ion-pair dissociation study, in particular, on determination of the energetic threshold. Here we report an experimental development for the ion-pair dissociation study by using the monochromized electron impacts. As an example, the threshold of BrCN→Br^-+CN^+ is determined as 13.78 eV according to the appearance energy of CN^+ signals, meanwhile, the time-sliced ion velocity image of CN^+ is recorded at 16.09 eV and indicates an anisotropic distribution of the CN^+ momentum.

（2＋1）-Dimensional Electron Acoustic Solitary Waves in an Unmagnetized Collisionless Plasma with Vortex-Like Hot Electrons

In this paper, （2＋1）-dimensional electron acoustic waves （EAW） in an unmagnetized collisionless plasma have been studied by the linearized method and the reductive perturbation technique, respectively. The dispersion relation and a modified Kadomtsev-Petviashvili （KP） equation have been obtained for the EAW in the plasma considering a cold electron fluid and a vortex-like hot electrons. It is found from some numerical results that the parameter β（the ratio of the free hot electron temperature to the hot trapped electron temperature） effects on the amplitude and the Width of the electron acoustic solitary waves （EASW）. It can be indicated that the free hot electron temperature and the hot trapped electron temperature have very important effect on the characters of the propagation for the EASW.

Effects of Adiabatic Dust Charge Fluctuation and Particles Collisions on Dust-Acoustic Solitary Waves in Three-Dimensional Magnetized Dusty Plasmas

Taking into account the combined effects of the external magnetic field, adiabatic dust charge fluctuation and collisions occurring between the charged dust grains and neutral gas particles （dust-neutral collisions）, the dust-acoustic solitary waves in three-dimensional uniform dusty plasmas are investigated analytically. By using the reductive perturbation method, the Korteweg-de Vries （KdV） equation governing the dnst-aconstic solitary waves is obtained. The present analytical results show that only rarefactive solitary waves exist in this system. It is also found that the effects of the wave vector along the z-direction, dust charge variation, collisional frequency, the plasma density, and temperature ratio can significantly influence the characteristics of low-frequency wave modes. Moreover, for the collisional dusty plasmas, there is a certain critical value μc of the plasma density ratio μ, if μ 〈 μc, the width of the waves increases with μ, otherwise the width of waves decreases with μ.

ELECTRON TRANSFER COLLISION OF NEON IONS WITH Ne IN A RF ION TRAP

The pulsed electron beam rf ion storage system is used to study neon ions electron transfer, The rate coefficients for electron transfer of the neon ions with the neon gas are measured, the results are better than those in other ion storage system.

CORRECTION OF INFLUENCE OF SUBSTRATE ON MEASUREMENT OF INNER SHELL IONIZATION CROSS SECTIONS

The energy spectra of reflected electrons from the substrates of targets have been calculated by the bipartition model of electron transport, the contributions of the inner shen ionization events produced by the reflected electrons from the substrates in the targets to the x-ray counting in a St(Li) detector have been estimated. It has been confirmed that, by such correction to the measured data, the experimental results of inner shell ionization cross sections by electron impact with fine precision may be obtained under the condition of thick substrate.

Quantum Transport Theory for Fusion Plasmas

Fundamental quantum transport equation for impact-ionization processes in fusion plasmas is formulated in the actor-spectator description. The density-matrix formulism is adopted to treat both coherent and incoherent effects in a unified fashion. Quantum electrodynamic effects are also considered for high-temperature scenarios. Electron-impact ionization of uranium ion U91＋ and proton-impact ionization of hydrogen are given as examples.

Effect of Higher Order Axial Electron Temperature on Self-Focusing of Electromagnetic Pulsed Beam in Collisional Plasma

Effect of higher order axial electron temperature on self-focusing of electromagnetic pulsed beam in collisional plasma is investigated.It is shown that higher order axial electron temperature T p4 is not trivial than T p0 and T p2,which can modify slightly radial redistribution of electron density and increases effective dielectric constant.As a result,on one hand,slightly reduce electromagnetic beam self-focusing in the course of oscillatory convergence,on the other hand,quicken beam divergence in the course of steady divergence,i.e.,higher order axial electron temperature T p4 can decrease the influence of collisional nonlinearity in collisional plasma.