Simulation of Large-Scale Disturbances of the Near-Earth Plasma Affected by High-Power High-Frequency Radio Waves from the Sura Heating Facility

Radiophysics and Quantum Electronics - We present the results of simulation of large-scale disturbances of the near-Earth plasma modified by high-power HF radio waves from the Sura heating...     

Ambiguity of the Reconstruction of Plasma Frequency Profiles from a Given Height-Frequency Characteristic and Their Discernibility for Oblique Propagation of HF Radio Waves in an Isotropic Ionosphere

We specify the formulation of the problem of reconstructing the plasma frequency height distribution from a given height-frequency characteristic (HFC) for a spherically symmetric isotropic ionosphere. We propose a numerical algorithm for solving the problem of correctly processing the region of near-critical frequencies of ionospheric layers. On this basis, we study the discernibility of plasma frequency profiles (PFPs) satisfying a given HFC when the properties of an obliquely propagating HF signal are analyzed.     

Dependence of Doubly Charged Ion Formation by the Two-Electron Mechanism on the intensity of Laser Radiation

Experimental dependences of the doubly charged ion yield N ²⁺ on the laser radiation intensity F are analyzed for the case of ion formation by the two-electron mechanism. It is shown that the region where the dependence N ²⁺(F) is characterized by the degree of nonlinearity K≈2.5 corresponds to the saturation of the process of doubly charged ion formation. This region is described well by theoretical calculations performed for Gaussian laser beams.     

样品温度对激光诱导土壤等离子体辐射特性的影响

为了研究样品温度对激光诱导等离子体辐射特性的影响,以国家标准土壤样品为靶,在空气中利用波长为1 064nm的Nd∶YAG纳秒脉冲激光烧蚀不同温度(≤350℃)下的片状样品,测量了激光诱导等离子体的发射光谱强度和信噪比,计算了光谱分析检出限和信号的测量准确度.实验结果表明,当能量为200mJ时,随着样品温度的升高,等离子体辐射逐渐增强,并且在样品温度为300℃时达到最大值.计算表明,元素Al、Mg、Ba和Fe在300℃样品温度时的光谱线强度比室温条件下分别提高了67%、58%、61%和52%,信噪比分别增大了41%、51%、28%和38%,且元素分析检出限和光谱信号稳定性均有改善.升高样品温度有利于改善激光光谱的质量.     

Dependence of the Intensity of the Spectral Lines and the Composition of the Sample and the Plasma Parameters of the Unipolar Arc

The investigation was made of the dependence of the intensity of Tl, Ga, Mo, Mg, Mn, Sn, Bi, Ni, Zn, Pt and Au spectral lines and the plasma parameters (temperature T, electron concentration n_e, degree of 6 ionnization α) from concentration of lithium additive.     

Analysis of the Dependence of the Break-Down Point on Temperature of Microwave Heating of Loaded Heterogeneous Materials (Rocks) Based on the Formation of Growth of Microcracks

Technical Physics - Analysis of the dependence of the break-down point of granite on the temperature of microwave heating allows identification of the following characteristic areas: hardening is...     

样品温度对纳秒激光诱导Cu等离子体特征参数的影响

为了研究样品温度对激光诱导击穿Cu等离子体特征参数的影响,以黄铜为研究对象,在优化的实验条件下采用波长为532 nm的Nd∶YAG纳秒脉冲激光诱导激发不同温度下的块状黄铜,测量了Cu等离子体的特征谱线强度和信噪比;同时在局部热平衡条件下利用Boltzmann斜线法和Stark展宽法分析计算了不同的样品温度条件下等离子体电子温度和电子密度。实验结果表明,在激光功率为60 mW时,随着样品温度的升高,Cu的特征谱线强度和信噪比逐渐增加,样品温度为130 ℃时达到最大值,然后趋于饱和。计算表明,黄铜样品中Cu元素Cu Ⅰ 329.05 nm,Cu Ⅰ 427.51 nm,Cu Ⅰ 458.71 nm,Cu Ⅰ 510.55 nm,Cu Ⅰ 515.32 nm,Cu Ⅰ 521.82 nm, Cu Ⅰ 529.25 nm,Cu Ⅰ 578.21 nm八条谱线在130℃的相对强度相较于室温（18 ℃）下分别提高了11.55倍、4.53倍、4.72倍,3.31倍、4.47倍、4.60倍、4.25倍、4.55倍,光谱信噪比分别增大了1.35倍,2.29倍、1.76倍、2.50倍、2.45倍、2.28倍、2.50倍,2.53倍。分析认为,升高样品温度会增大样品的烧蚀质量,相对于温度较低状态增加了等离子体中样品粒子浓度,进而提高等离子体发射光谱强度。所以,适当升高样品温度能够提高谱线强度和信噪比,从而增强LIBS技术检测分析光谱微弱信号的测量精度,改善痕量元素的检测灵敏度。同时研究了改变样品温度时等离子体电子温度和电子密度的变化趋势。计算表明,当样品温度从室温上升到130 ℃的过程中,等离子体的电子温度由4 723 K上升到7 121 K时基本不再变化。这种变化规律与发射谱线强度和信噪比变化趋势一致。分析认为,这主要是由于在升高样品温度的初始阶段,激光烧蚀量增大,等离子体内能增大,从而导致等离子体电子温度升高。当激光烧蚀样品的量达到一定值后不再变化,激光能量被激发溅射出来的样品蒸发物以及尘粒的吸收、散射和反射,导致激光能量密度降低,电子温度趋于饱和,达到某种动态平衡。选用一条Cu原子谱线（324.75 nm）的Stark展宽系数计算激光等离子体的电子密度,同时研究改变样品温度时等离子电子密度的变化趋势,计算表明在样品温度为130 ℃时,Cu Ⅰ 324.75 nm对应的等离子电子密度相较于室温（18 ℃）条件下增大了1.74×1017 cm-3。该变化趋势与电子温度的变化趋势一致。适当升高样品温度使得电子密度增大,从而提高电子和原子的碰撞几率,激发更多的原子,这是增强光谱谱线强度的原因之一。由此可见,升高样品温度是一种便捷的提高LIBS检测灵敏度的有效手段。     

Evolution of the Plasma Universe: II. The Formation of Systems of Galaxies

The model of the plasma universe, inspired by totally unexpected phenomena observed with the advent and application of fully three-dimensional electromagnetic particle-in-cell simulations to filamentary plasmas, consists of studying the interaction between field-aligned current-conducting, galactic-dimensioned plasma sheets or filaments (Birkeland currents). In a preceding paper, the evolution of the interaction spanned some 108-109 years, where simulational analogs of synchrotron-emitting double radio galaxies and quasars were discovered. This paper reports the evolution through the next 109-5 × 109 years. In particular, reconfiguration and compression of tenuous cosmic plasma due to the self-consistent magnetic fields from currents conducted through the filaments leads to the formation of elliptical, peculiar, and barred and normal spiral galaxies. The importance of the electromagnetic pinch in producing condense states and initiating gravitational collapse of dusty galactic plasma to stellisimals, then stars, is discussed. Simulation data are directly compared to galaxy morphology types, synchrotron flux, Hi distributions, and fine detail structure in rotational velocity curves. These comparisons suggest that knowledge obtained from laboratory, simulation, and magnetospheric plasmas offers not only to enhance our understanding of the universe, but also to provide feedback information to laboratory plasma experiments from the unprecedented source of plasma data provided by the plasma universe.     

The Results of Measurements of Features of Artificial Electromagnetic and Plasma Perturbations in the Outer Ionosphere of the Earth Using the DEMETER Satellite

The results of the DEMETER satellite mission for 2005–2010 are summarized. The characteristics of electromagnetic and plasma perturbations induced in the F₂ layer of the Earth’s ionosphere by the highpower HF radio waves from the SURA heating facility are analyzed.     

雷电的形成威力及预防

雷电灾害严重危及生命和财产的安全。因此，了解雷电成因，既有助于认识雷电的危害性，又可加强人类对雷电的防护。     

Spatial and Temporal Characterization of Distilled Water Plasma Using Laser-Induced Breakdown Spectroscopy: Effect of Self-Absorption on Plasma Parameters

The spatiotemporal evolution of the plasma induced by interaction of an Nd-YAG laser pulse with the surface of distilled water is described. The temporal evolution from 200 ns after the plasma creation to 2200 ns of the H _α and H _β lines is reported. Supposing the local thermodynamic equilibrium, the two plasma parameters, electron density and temperature, are determined, including the influence of the self-absorption on its measurements. The spatial evolution of the H _β intensity and of the electron density is given.     

Dependence of the Characteristics of Spectrally Narrow Luminescence Lines in Nanodiamonds on the Excitation and Temperature Parameters

Physics of the Solid State - The influence of the parameters of exciting radiation and temperature on the spectral characteristics of the narrow photoluminescence lines of nanodiamonds obtained by...     

壁面催化对再入飞行器等离子体鞘套及电磁参数的影响

针对超高声速流动中的高温真实气体效应,采用数值模拟求解考虑化学非平衡的三维Navier-Stokes(N-S)方程,研究了壁面催化对典型再入飞行器等离子体鞘套及电磁参数的影响规律.研究发现:(1)完全催化壁条件下等离子体密度计算结果与飞行试验符合较好;(2)完全催化壁条件下,离解原子在壁面的复合导致波后气体可压缩性增强...     

A technique for manufacturing passive HF and UHF elements based on high-temperature superconducting YBCO films: Parameters of test samples

The results from measurements of superconducting resonators and filters in both the HF and UHF range are described. These resonators and filters were made using YBCO thin films. Performance of the fabricated samples is no worse than the performance reported in the literature, demonstrating the high level of laboratory techniques developed at the IPM.     

Estimates of the Dependence of the Fusion Neutron Yield on the Initial Plasma Density and Temperature in Fast Pinches

JETP Letters - The neutron generation by hot, dense, and fast Z- and Θ-pinch plasma with the parameters achievable at the present development stage of high-power pulsed technology has been...     

The Effect of Thermionic Electron Emission on the Formation of Amorphous Metallic Nanoparticles in a Laser-Jet Plasma

Technical Physics - In recent years, the interest in using the structures consisting of amorphous nanoparticles has increased significantly due to their peculiar electric, magnetic, and catalytic...