Estimation of field in plane impedance waveguide with local geometrical inhomogeneity. I

The effect of an inhomogeneity in the form of a circular cylinder the properties of whose base are described by a certain impedance and whose lateral surface is ideally conducting on the field of a point source in a plane impedance waveguide is studied. In a scalar approximation, the problem is reduced to a two-dimensional integral equation over the surface of the inhomogeneity. A solution is constructed by the method of successive approximations; the solution of the problem for a regular impedance waveguide is used as an initial approximation. The effect of a local ionospheric inhomogeneity on the field of an electrical dipole in the earth-ionosphere waveguide is estimated.Leningrad State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 34, No. 8, pp. 908–918, August, 1991.     

局部不均匀性对时空系统振荡频率的影响

以复金兹堡一朗道方程为模型,利用数值实验方法观察了时空系统中螺旋波斑图的演化行为,发现在局域非均匀参数条件下,系统的螺旋波可以受到该杂质区域的影响而演化成为稳定的靶波.研究表明,内传的螺旋波转换为稳定靶波的必要条件是非杂质系统和杂质系统的振荡频率相等且小于系统的固有频率,并在参数一频率空间形成一个特殊的V形区域,进一步分析表明,该V形区域具有左右对称、两侧靶波传播方向相反以及随杂质区域参数α_2的增大而向参数β_2减小方向平移等性质.     

Allowance for near fields in the problem of local height inhomogeneity of the earth-ionosphere cavity

Radio-Astronomical Institute, Academy of Sciences of the Ukrainian SSR. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 33, No. 1, pp. 12–16, January, 1990.     

Study on 3-D arc plasma fields with holographic interferometry

In this paper,serveral temperature(refractive index)fields which are de-scribed by different kinds of functions are reconstructed by computer simulations based onholographic tomography theory.The obtained results are compared and analyzed.We de-signed a special multibeam holographic system in which the disturbance from the intense arclight can be filtered.With the system multidirectional holographic interferograms of arc fieldscan be taken simultaneously.We also calculate the quantitative distributions of temperature,the number density of particles and ionicity at a typical section of the argon arc field from theexperimeantal data.     

Scattering characteristics of 3-D discontinuity consisting of semiconductor sample filled in waveguide with gaps

The scattering characteristics of 3-D discontinuity consisting of II-VI-epitaxial layer grown on lossy dielectric substrate inserted in the waveguide with gaps are investigated in detail by the method which combines the multimode network theory with the rigorous mode matching procedure. The experimental data verify the accuracy and the effectiveness of the present method.     

Classical chaotic dynamics of sound rays in 3-D inhomogeneous waveguide media

The chaotic dynamics of sound rays in a near-bottom waveguide channel is studied on the basis of the Hamiltonian dynamics of nonparaxial rays in inhomogeneous moving media. The bottom is assumed to have a two-dimensional roughness. The mapping of the coordinates of the rays upon reflection from the rough bottom is derived through a solution of the corresponding ray equations in an unperturbed waveguide with a horizontal bottom. A numerical analysis of the mapping reveals that a chaotic instability of rays which start out at small angles from the horizontal develops at short distances from the source. Because of this instability, the path segments of a ray along the horizontal coordinates and the signal passage time along a ray are random functions of the angle at which the ray emerges from the source. Upon a further reflection of rays from the rough bottom, there is a diffusion of rays in a stochastic ring which forms in the plane of horizontal ray directions as a result of the overlap and intersection of resonance curves. A qualitative analysis of this effect is carried out. This effect leads to a nearly isotropic distribution of ray directions.     

Propagation of electromagnetic waves in the earth-ionosphere waveguide with a gradual periodic inhomogeneity of the ionospheric upper-boundary impedance

We study the influence of a gradually inhomogeneous periodic disturbance of the upper-wall impedance of a plane Earth-Ionosphere waveguide on the radiation of a vertical electric dipole immersed in the waveguide channel. We consider the case where the disturbance amplitude is commensurable with the undisturbed value of the impedance. An expression is obtained for the Hertz potential when the source and the observation point are located at the lower wall of the waveguide. Radiophysical Research Institute, Nizhny Novgorod, Russia. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 41, No. 3, pp. 374–383, March, 1998.     

On solution of the vector 3-D locally irregular waveguide problem

The vector 3-D problem of a point-source field in a plane waveguide with a large-scale local inhomogeneity on one of its walls is considered. The field components on the boundary surfaces comply with the Leontovich conditions, which are used as a basis for obtaining expressions for the derivatives of the field vectors normal to the boundaries; these expressions reflect the 3-D nature of the inhomogeneity. The problem is reduced to a system of 2-D integral equations allowing for overexcitation and depolarization of the field scattered by the irregularity. The system of 2-D integral equations is asymptotically transformed over the inhomogeneity region on the surface of the walls bounding the waveguide space into a system of linear integral equations, for which the integration contour is represented by the line between the source and observation point, as well as by the linear geometric contour of the irregularity.State University, St. Petersburg. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 38, No. 8, pp. 785–803, August, 1995.     

Mode matching analysis of the dielectric waveguide 3-D discontinuity problem

In this paper, the dielectric waveguide 3-D discontinuity problem is investigated by the method which combines the multimode network theory with the rigorous mode matching procedure both in the transverse cross section and in the longitudinal direction. Good agreement has been found between the numerical results and the experimental data in the literature, and the effectiveness and accuracy of the present method are justified. Some numerical results are given to establish useful guidelines for the design of dielectric waveguide components in the millimeter and optical wave integrated circuits.     

电磁场统一性质的三维描述

论述了电场与磁场本质上的统一性质,构造了三维空间中电磁场的统一场量,给出它的方程、场量的模方与能量和动量的关系,发现三维空间中的统一场量自身的标积竟然是相对论变换下的不变量．     

自适应发射光谱体层析技术重建三维等离子体场

提出一种基于多目标优化原理的自适应权重因子调节发射光谱体层析图像重建新算法SVRT(Self_adap tiveVolumeReconstructionTechnique)。通过计算机数值模拟,考察了该算法对非对称单峰发射系数场分布的重建效果。结果表明,SVRT算法具有收敛快,重建精度高的特点,仅用两个方向的投影数据就能高精度地重建单峰三维发射系数场分布。作为一个应用实例,结合谱线相对强度测量方法重建了自由电弧等离子体的三维温度场及电离度场分布。     

Study of the vertical electric dipole in an earth-ionosphere waveguide with a smooth stochastic inhomogeneity of the upper boundary impedance

We study the effect of a smoothly inhomogeneous stochastic disturbance in the impedance of the upper wall of a plane Earth-ionosphere waveguide on the field of the vertical electric dipole placed in the waveguide channel. The case where the disturbance variance is comparable to the mean impedance is considered. An expression for the Hertz potential is found, and the conditions for use of the Bourre approximation are specified. Radiophysical Research Institute, Nizhny Novgorod, Russia. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 40, No. 4, pp. 457–471, April, 1997.