对含有非热力学平衡离子的尘埃等离子体中孤波特性的理论研究

得到了描述由尘埃颗粒电荷变化、非热力学平衡分布的离子和Boltzmann分布的电子组成的未磁化的热尘埃等离子体中的尘埃声波的修正的KdV (mKdV) 方程. 并对诸多的尘埃等离子体参数对尘埃声孤波结构的影响进行了理论研究，结果表明，尘埃等离子体参数决定着尘埃声孤波结构，且只在这些参数特别选定的一些区域，才会出现稳定的孤波. 关键词： 非热力学平衡离子 尘埃颗粒电荷变化 尘埃声孤波     

Fine structure of the spectra of magnetic particles in the vortex state and their ordered arrays

A low-frequency (the frequency ω_VPM is in the sub-GHz range) mode exist for submicron magnetic particles in the vortex state. This mode corresponds to oscillations of the vortex center. The other modes form doublets with higher (several gigahertz) frequency and small (about ω_VPM) splitting. Collective oscillations exist for lattices of such particles. The dependence of the frequency of these modes on the quasi-momentum can be nonanalytic.     

Accurate determination of the spin Hamiltonian parameters for Mn2+ ions in cubic ZnS nanocrystals by multifrequency EPR spectra analysis

Accurate determination of the spin Hamiltonian (SH) parameters, describing the electron paramagnetic resonance (EPR) spectra of paramagnetic impurity ions in wide band gap semiconductor nanocrystals, is essential for determining their localization and quantum properties. Here we present a procedure, based on publicly available software, for determining with higher accuracy the SH parameters of isolated Mn(2+) impurity ions in small cubic ZnS nanocrystals. The procedure, which can be applied to other cubic II-VI semiconductor nanocrystals as well, is based on the analysis of both low and high frequency EPR spectra with line shape simulation and fitting computing programs, which include the hyperfine forbidden transitions and line broadening effects. The difficulties, limitations and errors which can affect the accuracy in determining some of the SH parameters are also discussed.     

Shifts of one-electron ions lines from n = 0 interactions with electrons in hot and dense plasma

This paper is concerned with lineshifts of hydrogen-like ions due to electron collisions in dense and hot plasmas. These collisions are treated by including all effects due to monopole, dipole, and quadrupole interactions between radiator and electron perturbers. The latter follow exact hyperbolic trajectories with a possible penetrating part inside atomic orbits. A simple closed form for the line shift has been derived. Comparison between our semi-classical results and the quantum mechanical ones shows good agreement for a large range of high electron densities and temperatures. Received: 30 June 1997 / Revised: 28 April 1998 / Accepted: 29 April 1998     

Amplification of mean magnetic field and magnetic helicity production in hot lepton plasma of early universe

We argue that the magnetic helicity conservation is violated at the lepton stage in the evolution of early Universe owing to the parity violation in the Standard Model of electroweak interactions. As a result, a cosmological magnetic field which can be a seed for the galactic dynamo obtains from the beginning a substantial magnetic helicity which has to be taken into account in the magnetic helicity balance at the later stage of galactic dynamo. The particle physics mechanism suggested in our works depends neither on helicity of matter turbulence with plasma vortices resulting in the standard α effect in dynamo theory nor on general rotation. The mechanism can result in a self-exitation of an (almost) uniform cosmological magnetic field. The text was submitted by the authors in English.     

Pair production from hot plasma in the presence of a strong magnetic field

Acta physica Academiae Scientiarum Hungaricae - Radiation loss due to pair production by an intense electromagnetic wave is calculated. The calculations were made in the coulomb field of the ions...     

X-ray spectra of multiply-charged hollow ions in the emission from a femtosecond laser plasma

A new type of quasicontinuous emission spectrum from a femtosecond laser plasma near the Ly_α line of H-like ions is obtained and interpreted. It is shown that these spectra are emitted by multiply charged hollow ions, which are present in the plasma on account of its ultrahigh density, which, in turn, is due to the use of high-contrast laser pulses for producing the plasma. A new spectroscopic approach based on analysis of the composition of spectral complexes of hollow ions is discussed. Pis’ma Zh. éksp. Teor. Fiz. 67, No. 7, 467–472 (10 April 1998)     

间接驱动的内爆不对称性随腔长和时间变化的研究

在激光间接驱动惯性约束聚变中, 为达到高密度压缩以实现点火, 对靶丸内爆对称性和黑腔辐射场均匀性有严格的要求. 为了研究内爆不对称性随腔长和时间的变化, 实验中采用了三种不同尺寸的黑腔, 利用X光分幅相机观测了靶丸燃料区自发光, 获得了压缩变形过程和椭圆度变化规律, 初步判断了在三种腔型中腔长1700 μm 的黑腔较接近神光Ⅲ原型装置内爆对称性要求. 根据视角因子程序计算得到辐射流不对称性随时间变化情况, 通过一个简化的解析模型推导出内爆形变不对称性随时间变化过程, 与实验结果大致符合. 由此进一步分析了黑腔辐射场不均匀性的演化导致内爆不对称性随腔长和时间变化的物理机制. 关键词： 内爆不对称性 黑腔辐射场不均匀性 腔长 视角因子程序     

X-ray spectra of He-like ions of Ga and Ge,excited in the low-inductance spark plasma

The spectra of Ga XXX and Ge XXXI ions in the interval 1.2–1.4 Å excited in the low-inductance vacuum spark plasma have been obtained for the first time. The resonance line 1s²?1s2p of Ga XXX and Ge XXXI and a group of satellites, corresponding to transitions in Ga XXIX and Ge XXX can be seen distinctly in the spectra. The spectra were obtained by an electronic-optical image-intensifier tube for one discharge.     

Spin-spin and spin-other-orbit effects of optical spectra and the spin-Hamiltonian parameters for Cr ions in MgO crystals

An extended complete diagonalization method/microscopic spin-Hamiltonian (CDM/MSH) program has been developed, which is applicable for d³ ions at sites of tetragonal symmetry type I (C_4v, D_2d, D₄, D_4h) and trigonal symmetry type I (C_3v, D₃, D_3d). The Hamiltonian includes the spin-spin (SS) and spin-other-orbit (SOO) magnetic interactions besides the spin-orbit (SO) magnetic interaction usually taken into account. Utilizing the extended CDM/MSH program, the optical spectra, the spin-Hamiltonian (SH) parameters of the ground state ⁴B₁, and the splitting δ(²E) of the first excited ²E state for Cr³⁺ (3d³) ions at C_4v symmetry sites in MgO crystals have been successfully investigated. It is found that although the SO magnetic interaction is the most important one, the contributions to the SH parameters and the optical spectra from the SS and SOO magnetic interactions for Cr³⁺:MgO crystals are appreciable and should not be omitted, especially reaching 27.8% for the zero field splitting parameter D.     

Method for measuring the electron distribution function in the low temperature plasma with a high time resolution

A hybrid method for measuring the electron distribution function in the low temperature plasma is described. The time resolution of the measurement is of the order of several sec.     

Studies of the optical spectra and spin-Hamiltonian parameters for the trivalent ytterbium ions in lithium yttrium fluoride crystals

In this paper, the crystal field (CF) levels and spin-Hamiltonian (SH) parameters (g factors g _∥ and g _⊥ and hyperfine structure constants A _∥ and A _⊥) of the rare-earth ion Yb³⁺ in lithium yttrium fluoride crystals are calculated under D _2d point symmetry assumption. Two main methods are used in the calculation to study the SH parameters: one is the perturbation theory method and the other is the complete diagonalization (energy matrix) method (CDM). Comparing the calculated results with the experimental data, we can see that the CDM is more effective to calculate the SH parameters. In addition, the CF J-mixing of all excited-state multiplets into the ground-state multiplet ²F_7/2 is considered. The validity of the calculated results is discussed.     

Kinetic equations for ions in plasma with ion-acoustic turbulence in the case of two ion types

Explicit expressions for ion kinetic equations were derived considering ion-acoustic turbulence of plasma, when the presence of two ion types enhances stimulated scattering of ionacoustic waves on ions.     

利用力学-光学技术实现地磁水平分量实时监控

利用力学和光学技术设计了一种测量地磁场水平分量的装置.在扭力矩和磁力矩作用下,线圈做简谐振动.测量简谐振动的周期和两次平衡位置的相对距离即可计算出地磁场水平分量.该装置结构简单,测量结果准确,可以实现动态实时测量.     

Formation of the spectra of multiply charged ions from the plasma of Nd-doped glass irradiated with a neodymium laser

The effect of neodymium ions on laser-induced glass destruction and the formation of the spectra of laser plasma ions is studied by the mass-spectrometric and optical-microscopy methods. As the Nd ion concentration increases, the degree of laser-induced damage in silicate glass increases, the threshold intensity for the glass destruction decreases, the maximum ion charge number Z_max and the maximum ion energy E_max decrease, and the energy spectra of target ions change. All this is related to both the coincidence between the lasing lines and the absorption bands of Nd ions and the intensifi cation of recombination processes in the multicomponent laser plasma.     

Effect of resonant magnetic perturbations on edge plasma parameters in the STOR-M tokamak

Edge plasma properties have been modified in the Saskatchewan Torus-Modified tokamak by means of resonant magnetic perturbations (RMP). It has been found that the radial profiles of ion saturation current and floating potential in the edge region can be modified by an externally applied static (m?=?2, n?=?1) RMP field. An increase in the pedestal plasma density (n) and more negative electric field (E_r) have been observed in the plasma edge region. It is believed that the RMP field altered the plasma transport in the edge and scrape-off layer regions, leading to a higher density pedestal and a potential drop in some cases. During the enhanced confinement phase, it is possible to identify a region where intermittent transport events, the so-called blobs, are created and the holes of lower density left behind.