Au激光等离子体M带5f-3d跃迁的光谱参数

用超组态碰撞辐射模型模拟非局域热动力学平衡中Au的M带谱5f-3d跃迁的离子电离态特性，激光等离子体的光谱跃迂参数是必不可少的。利用多组态Dirac-Fock广义扩展平均能级方法，用GRASP^2系统地计算了激光Au等离子体中类铁金离子-类锗金离子的M带谱5f-3d的光谱跃迁波长．跃迁几率和振子强度，计算中考虑了重要的核的有限体积效应、Breit修正和QED修正，所得结果和最近的实验数据及理论计算值进行了比较。此结果可应用于对激光等离子体的模拟和诊断。     

Nanomorphological characteristics of the single-crystal Si(100) surface subjected to microwave plasma processing at weak adsorption

The influence of the conditions and composition of the highly ionized plasma of an electron cyclotron resonance low-pressure microwave gas discharge on the nanomorphology of the single-crystal Si(100) surface is studied. Model mechanisms of the processes controlling the main nanomorphological parameters of silicon crystals subjected to low-energy microwave plasma processing in chemically active and inactive gaseous media under the conditions of weak adsorption are considered.     

Saturation current densities at the critical point of a spherical probe in a moving collisional plasma with negative ions or dust grains

The problem is considered of the probe diagnostics of a moving, weakly ionized, collision-dominated plasma containing singly charged negative ions or dust grains (heavy multicharged ions). Based on an asymptotic analysis, expressions are obtained that describe the saturation current densities of the electrons and of the charged particles of other species at the point where the plasma flowing around a spherical probe in the laminar boundary layer regime stagnates.     

On the Effect of Electron's Runaway in Partially Ionized Hydrogen Semiclassical Nonideal Plasma

The effect of runaway electron for semiclassical partially ionized hydrogen dense plasma is studied in this work. Dependencies of friction force acting to electrons on coupling parameters were obtained. The relative number of runaway electrons as the function of their temperature was considered for semiclassical model of dense plasma. It has been shown that the differences between the relative number of runaway electrons values can be significant for various plasma models (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Thermally Conducting Partially Ionized Plasma in a Variable Magnetic Field

An infinitely extending homogenous partially ionized plasma endowed with several physical mechanisms and permeated by a variable magnetic field is considered. The combined effect of these parameters, namely, Hall currents, finite conductivity, ion viscosity, collision with neutrals and thermal conductivity on the gravitational instability of the plasma is studied. It is found that the several mechanisms play different physical roles in the perturbed problem. Jeans' Criterion is analyzed in the framework of Tsallis' statistics for possible modifications due to the presence of nonextensive effects. A simple generalization of the Jeans' criterion is obtained and the standard values are obtained in the limiting case q = 1, q being the nonextensive parameter. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Measurement of the quasi-isentropic compressibility of a helium plasma at a pressure of about 5000 GPa

The quasi-isentropic compressibility of a helium plasma has been measured using a spherical experimental chamber, as well as an X-ray diffraction complex consisting of three betatrons and a multichannel optoelectronic system for the detection of X-ray images. The density of the compressed helium plasma of about 8 g/cm³ has been obtained in the experiment at a pressure of 5000 GPa. Analysis of the data indicates that helium at the measured parameters is in a single ionized state.     

Self-sustained oscillations in a plasma-wall system with strongly inhomogeneous diffusion of charged particles

A simple system with a hydrogen plasma confined by a magnetic field parallel to the bounding material wall is considered. The charged particles diffuse out of the plasma, recombine on the wall and return into the plasma volume as neutrals, which are ionized by electrons. It is demonstrated that macroscopic self-sustained oscillations are an intrinsic feature of such a system if the diffusion coefficient of charged particles is strongly inhomogeneous in the plasma.     

p型半导体金刚石膜的磁阻效应

在p型硅(100)衬底上,采用衬底负偏压微波等离子体CVD方法进行了p型异质外延金刚石膜的生长.用O₂等离子体刻蚀技术将金刚石膜刻蚀成长条形,利用四探针法在0—5T的磁场范围内测量了样品的磁阻.实验结果表明,p型异质外延金刚石膜可以产生较大的磁阻.在Fuchs-Sondheimer(F-S)薄膜理论的基础上考虑晶格散射、杂质散射和表面散射,通过求解Boltzmann方程,利用并联电阻模型研究了p型异质外延金刚石膜的磁阻效应,给出了磁阻和金刚石膜厚度、迁移率、空穴密度及磁场的关系.讨论了表面散射和价带形变对p型异质外延金刚石膜磁阻的影响,初步解释了p型异质外延金刚石膜产生较大磁阻的原因 关键词： 金刚石膜 异质外延 磁阻效应 电导率     

Formation of atomically clean silicon surfaces in a low-energy low-pressure microwave plasma

The influence of the regimes and chemical composition of the low-energy highly ionized ECR plasma of a low-pressure microwave gas discharge on the etch rate and nanomorphology of differently oriented single-crystal silicon surfaces is studied. Model mechanisms of the processes controlling the etch rate and etch quality of atomically clean silicon surfaces with a desired orientation are considered.     

Existence of He- ions in a duoplasmatron discharge

We point out the presence of He^- ions in a duoplasmatron discharge and detect currents of 10^-15 A. The influence of different parameters on this current is indicated and possible processes for the formation of He^- ions are investigated.     

On the Cd III spectrum in a pulsed helium discharge

On the basis of the spectral line intensity relaxation during the plasma decay, fifty six spectral lines between 219 nm and 330 nm in the cadmium (Cd) spectrum were identified as Cd III (doubly ionized) or Cd IV (triply ionized) lines. The measured Stark widths of twelve, the most intense spectral lines around 315±15 nm with well defined profiles, are presented. Investigated spectral lines originate from the high lying energy levels, not classified up to now. A linear low-pressure pulsed arc was used as an optically thin plasma source. A pulsed discharge was produced in a pyrex discharge tube. Helium was chosen as the carrier gas. The cadmium atoms were sputtered from the thin cadmium cylindrical plates located in the homogeneous axial part of the discharge tube. The helium plasma was operated at electron temperatures up to 19 000 K and 1.1 × 10²³ m^-3 electron density. The stepwise ionization processes via the high lying singly ionized (Cd II) energy levels, populated well due to the Penning and charge exchange effects, provide high density of the Cd III (and Cd IV) ions in our helium plasma. The temporal evolutions of the spectral line intensities were monitored using a spectrograph and an ICCD camera as a highly sensitive detection system.     

Investigation of the fundamental properties of a Coulombian plasma by the method of many-particle dynamics

It is shown that a completely ionized, classical, Coulombian plasma, placed in an adiabatic enclosure, possesses a stationary state. At the same time, a plasma placed in a thermostat recombines through triple collisions, with a velocity satisfactorily accounted for by well-known theoretical results. The results obtained by numerical modeling have shown that, for a plasma placed in an adiabatic enclosure, the ergodic assumption is not valid. Various possible kinetic mechanisms, ensuring the existence of a stationary state of the adiabatically enclosed plasma, are considered.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 11, pp. 3–34, November, 1991.     

Surface processing with partially ionized plasmas

Partially ionized plasmas are used extensively to process surfaces in many areas of technology. Surface processing in this discussion includes deposition of thin films, etching of the surface itself, and modification of the existing surface by oxidation, nitriding, or texturing. Unique materials can be synthesized in reactive gas glow discharges. The development and optimization of plasma processes is impeded by both a lack of understanding of the mechanistic details and by the formidable parameter space associated with plasma equipment. The complexity of the reactive gas plasma environment coupled with the large parameter space causes difficulty in process development and optimization, but offers opportunities for discovery and invention. The ability of partially ionized plasmas to generate uniform fluxes over wide areas of energetic ions and/or reactive neutral atoms or radicals can be expected to ensure continued widespread applications for the plasma processing of surfaces     

Modeling of a bimetallic eccentric cylindrical plasma waveguide based on a transmission line for TEM-mode

In this paper, a plasma waveguide made of two eccentric cylindrical metallic walls have been studied according to the theory of transmission lines. The inductance per unit length L, the capacitance per unit length C, the resistance per unit length R and the shunt conductance per unit length G are obtained. The graphs of variations of the mentioned parameters vs. geometrical dimensions of waveguide are investigated. This investigations have been done for two different types of plasma waveguide. At first stage, plasma region will be considered in cold and collisional approximation and in second stage, a drift plasma in cold collisionless approximation will be considered. Also, graphs of phase velocity variation vs. the main parameters of the waveguide are presented.     

Some properties of ion and cluster plasma

The aggregate of problems connected with the physics of ion and cluster plasma is qualitatively considered. Such a plasma can exist when a dense gas is ionized by a hard ionizer. The conditions for the formation of an ion plasma and the difference between its characteristics and those of an ordinary electron plasma are discussed; a solvated-ion model and the distribution of the clusters with respect to the number of solvated molecules are considered. The recombination rate of the positively and negatively charged clusters is roughly estimated. The parameters of a ball-lightning plasma are estimated on the basis of the cluster model.Translated from Trudy Fizicheskogo Instituta im. P. M. Lebedeva, Vol. 120, pp. 50–64, 1980.     

Ionization processes and charge-state distribution in a highly ionized high- Z laser-produced plasma

The charge-state distribution in a well-characterized highly ionized Au plasma was accurately determined using time-resolved x-ray spectroscopy. Simultaneous measurements of the electron temperature and density allow the first direct comparisons with nonlocal thermodynamic equilibrium model predictions for the charge-state distribution of a highly ionized high- Z plasma in a nonradiative environment. The importance of two-electron atomic processes is clearly demonstrated.     

Nanostructuring of the submonolayer carbon coatings deposited onto the surface of silicon single crystals in a low-pressure microwave discharge plasma

The surface nanostructuring of the submonolayer carbon coatings deposited onto (111) and (100) silicon wafers in a highly ionized ultrahigh-frequency low-pressure plasma is studied. The effect of the coating thickness and the main processing parameters on the mechanisms of morphological changes is studied with allowance for the reconstruction of a single-crystal silicon surface and the mechanical stresses that appear during the preparation of an atomically clean surface during plasma-chemical etching, heterogeneous condensation, and high-temperature annealing. Integral columnar nanosystems with a density of (4?C5) × 10⁹ cm^?2 and a height of 400 nm are formed on (100) silicon single crystals using nanostructured carbon aggregates as mask coatings and highly anisotropic plasma-chemical etching.     

Plasma Emission Mechanism from Duoplasmatron Hydrogen Arc?theoretical Model of the Arc

The mechanism of plasma emission from the duoplasmatron (DPT) is studied in terms of a model involving a "potential hump" and following the course of an ion (along the magnetic-field lines which are obtained by computational simulation) in moving towards and through the anode nozzle. The analysis of this model indicated the necessity for the "potential hump" in the arc and this corroborated the plasma potential measurements by single probe [14]. The plasma output is determined by the rate of production of ions, which is confined into the region defined by magnetic-field line on the anode side of the "potential hump." In view of this, estimated and measured values of the total output seem to be in good agreement. Therefore post-ionization in the anode cup as proposed by some researchers [8], [16] seems not to be necessary to account for the plasma output.     

瞬变等离子体微波诊断初步研究

采用微波诊断技术对气压300 Pa,S波段HPM条件下形成的低温、弱电离、非均匀和强碰撞大气等离子体特性参数开展了初步诊断研究。获取了9~15 GHz连续波穿过HPM等离子体区域的透射波形,并对波形进行了归一化处理;通过不同频率微波的透射特性,假设等离子体电子数密度分布呈Epstein分布,分析了可能的电子数密度最大值。该研究成果的获取为HPM大气等离子体在隐身、阻断信息链等方面的应用提供了重要的技术支撑。