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91.
S. Laha Y. C. Chen P. Gupta C. E. Simien Y. N. Martinez P. G. Mickelson S. B. Nagel T. C. Killian 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2006,40(1):51-56
A study of ion equilibration in annular regions of ultracold strontium plasmas is reported. Plasmas are formed by photoionizing
laser-cooled atoms with a pulsed dye laser. The experimental probe is spatially-resolved absorption spectroscopy using the
2S1/2-2P1/2 transition of the Sr+ ion. The kinetic energy of the ions is calculated from the Doppler broadening of the spectrum, and it displays clear oscillations
during the first microsecond after plasma formation. The oscillations, which are a characteristic of strong coulomb coupling,
are fit with a simple phenomenological model incorporating damping and density variation in the plasma. 相似文献
92.
During thermal plasma processing of materials, vapor generated from injected particulate matter will enter the plasma. Even traces of metallic vapors may have a strong effect on the properties and the behavior of the plasma and on the associated heat flux to the injected particles. In this paper a model system is considered in which an argon plasma at atmospheric pressure is contaminated by small amounts of copper vapor. By using the Chapman-Enskog approximation for a multicomponent gas mixture the transport properties are calculated for such a contaminated argon plasma. The results show that there is a drastic effect on the electrical properties. For temperatures below 104 K, the electrical conductivity, for example, increases by more than an order of magnitude if metallic vapor is present. The presence of metallic contaminants is also somewhat felt by the reactional thermal conductivity. In contrast, there is no effect on the heavy-particle properties as long as the percentage of the contaminants remains small. 相似文献
93.
利用一维辐射流体动力学程序MULTI数值模拟研究了功率为1014W/cm2、脉冲宽度为1ns、波长为0.35μm的短脉冲强激光辐照不同厚度的平面Au靶时,靶厚度对靶背面x射线能谱结构和辐射强度的影响.
关键词:
激光等离子体
辐射流体力学
x射线转换 相似文献
94.
Plasmas in modern tokamak experiments contain a significant fraction of impurity ion species in addition to main deuterium background. A new unlike-particle collision operator for δf particle simulation has been developed to self-consistently study the non-local effects of impurities on neoclassical transport in toroidal plasmas. A new algorithm for simulation of cross-collisions between different ion species includes test-particle and conserving field-particle operators. The field-particle operator is designed to enforce conservation of number, momentum and energy. It was shown that the new operator correctly simulates the thermal equilibration of different plasma components. It was verified that the ambipolar radial electric field reaches steady state when the total radial guiding center particle current vanishes. 相似文献
95.
Pierre Degond Fabrice Deluzet Laurent Navoret An-Bang Sun Marie-Hélène Vignal 《Journal of computational physics》2010,229(16):5630-5652
This paper deals with the numerical resolution of the Vlasov–Poisson system in a nearly quasineutral regime by Particle-In-Cell (PIC) methods. In this regime, Classical PIC methods are subject to stability constraints on the time and space steps related to the small Debye length and large plasma frequency. Here, we propose an “Asymptotic-Preserving” PIC scheme which is not subjected to these limitations. Additionally, when the plasma period and Debye length are small compared to the time and space steps, this method provides a consistent PIC discretization of the quasineutral Vlasov equation. We perform several one-dimensional numerical experiments which provide a solid validation of the method and its underlying concepts, and compare the method with Classical PIC and Direct-Implicit methods. 相似文献
96.
Satyabrata Sahoo Y.K. Ho 《Journal of Quantitative Spectroscopy & Radiative Transfer》2010,111(1):52-62
We present theoretical photoionization cross sections for He 1s2s 1S and He 1s2p 1P states in a Debye plasma environment by the complex coordinate rotation method, using a finite L2 basis set constructed from one electron Laguerre orbitals. The plasma environment is found to appreciably influence the photoionization cross sections near the ionization threshold. In this regard, the photoionization cross sections of isolated He are compared with other theoretical and experimental results. Our results are in good agreement with the previous results. A new minimum appears in the photoionization cross section curve for the metastable 1s2s 1S state. Results are given for the S- and D-wave partial photoionization for the excited 1s2p 1P state. 相似文献
97.
Jianqi Shen Huarui Wang Bingshan Wang Haitao Yu Bin Yu 《Journal of Quantitative Spectroscopy & Radiative Transfer》2010,111(5):772-2428
The Debye-series decomposition is of importance for understanding of light scattering features and for the validity of the geometrical optics approximation to light scattering. The numerical stability and accuracy for calculating light scattering with Debye series is studied and an improved algorithm is proposed in this work. The ratios of the Riccati-Bessel functions and the logarithmic derivatives of the Riccati-Bessel functions are employed and calculated with proper recurrences. Exemplifying results are provided to show the improvement of the algorithm. 相似文献
98.
99.
A. H.?KhaterEmail author D. K.?Callebaut M. A.?Helal A. R.?Seadawy 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2006,39(2):237-245
The nonlinear evolution
of the kink instability of a plasma
with an elliptic magnetic stagnation line is studied by means
of an amplitude expansion of the ideal magnetohydrodynamic equations.
Wahlberg et al. [12] have shown that, near marginal stability,
the nonlinear evolution of the stability can be described in terms
of a two-dimensional potential U(X,Y), where X and Y represent
the amplitudes of the perturbations with positive and negative
helical polarization. The potential U(X,Y) is found to be nonlinearly
stabilizing for all values of the polarization. In our paper a Lagrangian
and an invariant variational principle for two coupled nonlinear ordinal
differential equations describing the nonlinear evolution of the stagnation
line instability with arbitrary polarization are given. Using a trial function
in a rectangular box we find the functional integral. The general case for
the two box potential can be obtained on the basis of a different ansatz
where we approximate the Jost function by polynomials of order n instead
of a piecewise linear function. An example for the second order is
given to illustrate the general case. Some considerations concerning
solar filaments and filament bands (circular or straight) are
indicated as possible applications besides laboratory experiments
with cusp geometry corresponding to quadripolar cusp geometries for
some clouds and thunderstorms. 相似文献
100.
常压介质阻挡放电由于其具有均匀、散漫、稳定,而且不需要真空系统等优点,正日益受到人们的重视和研究。文章给出了常压介质阻挡放电的研究进展,包括实验装置、实验条件、放电机理以及最新的诊断方法,还介绍它在材料表面改性、环境工程、食品加工等方面的应用前景。 相似文献