SS-traveltime parameters from PP and PS reflections

Geophysics ◽  
2009 ◽  
Vol 74 (4) ◽  
pp. R35-R47 ◽  
Author(s):  
Bjørn Ursin ◽  
Martin Tygel ◽  
Einar Iversen
Keyword(s):  
Velocity Model ◽  
Ocean Bottom ◽  
Reflection And Transmission ◽  
Transmission Coefficients ◽  
Partial Reconstruction ◽  
Propagator Matrix ◽  
Geometric Spreading ◽  
Derivatives Of ◽  
Full Simulation ◽  
Original Formula

The SS-wave traveltimes can be derived from PP- and PS-wave data with the previously derived [Formula: see text] method. We have extended this method as follows. (1) The previous requirement that sources and receivers be located on a common acquisition surface is removed, which makes the method directly applicable to PS-waves recorded on the ocean bottom and PP-waves recorded at the ocean surface. (2) By using the concept and properties of surface-to-surface propagator matrices, the second-order traveltime derivatives of the SS-waves are obtained. In the same way as for the original [Formula: see text] method, the proposed extension is valid for arbitrary anisotropic media. The propagator matrix and geometric spreading of an SS-wave reflected at a given point on a target reflector are obtained explicitly from the propagators of the PP- and PS-waves reflected at the same point. These additional parameters provided by the extended [Formula: see text] method can be used for a partial reconstruction of the SS-wave amplitude as well as for tomographic estimation of the elastic velocity model. A full simulation of the SS-wave, which includes reflection and transmission coefficients, cannot be obtained directly from recorded PP- and PS-wave amplitudes.

scholarly journals Light Scattering by a Subwavelength Plasmonic Array: Anisotropic Model

Sensors ◽  
2022 ◽  
Vol 22 (2) ◽  
pp. 449
Author(s):  
Anton Nemykin ◽  
Leonid Frumin ◽  
David Shapiro
Keyword(s):  
Cross Sections ◽  
Total Internal Reflection ◽  
Light Transmission ◽  
Quantitative Agreement ◽  
Approximate Analytical Expression ◽  
Axis Ratio ◽  
Reflection And Transmission ◽  
Transmission Coefficients ◽  
The Media ◽  
Derivatives Of

We calculate the light transmission by a subwavelength plasmonic array using the boundary element method for parallel cylinders with different cross-sections: circular or elliptic with axis ratio 4:1. We demonstrate that plasmonic resonance is sharper for the case of horizontal ellipses. This structure is susceptible to refractive index variations in the media since the high derivatives of reflection and transmission coefficients are near the angle of total internal reflection. To obtain an approximate analytical expression, we used the model of a metallic layer. We explore the “sandwich” structure with an anisotropic film between two dielectrics and demonstrate its quantitative agreement with numerical results.

Propagation of Stress Gradient Through an Inclusion—Part 1

1973 ◽  
Vol 40 (3) ◽  
pp. 711-717 ◽  
Author(s):  
T. C. T. Ting ◽  
Shun-Chin Chou
Keyword(s):  
Composite Materials ◽  
Wave Front ◽  
Incident Wave ◽  
Stress Gradient ◽  
Higher Order ◽  
Elastic Media ◽  
Interface Boundary ◽  
Reflection And Transmission ◽  
Transmission Coefficients ◽  
Derivatives Of

This is the first of a two-part study on the propagation of stress gradient in composite materials. Both the plane-strain and axisymmetric motions are considered. In this paper, the reflection and transmission coefficients are derived for the stress, the stress gradient, and the higher-order derivatives of stress at an interface between two elastic media. It is shown that while the reflection and transmission of the stress do not depend on the geometries of the incident wave front and the interface boundary, the reflection and transmission of the stress gradient, and the higher-order derivatives of stress do depend on these geometries. Explicit expressions are derived for the reflection and transmission of the stress gradient in terms of the radii of curvatures of the incident wave front and the interface boundary.

Extension of forward modeling phase-screen code in isotropic and anisotropic media up to critical angle

Geophysics ◽  
2007 ◽  
Vol 72 (5) ◽  
pp. SM107-SM114 ◽  
Author(s):  
James C. White ◽  
Richard W. Hobbs
Keyword(s):  
Critical Angle ◽  
Model Space ◽  
Anisotropic Media ◽  
Forward Modeling ◽  
Phase Screen ◽  
Computationally Efficient ◽  
Reflection And Transmission ◽  
Transmission Coefficients ◽  
Phase Corrections ◽  
Converted Phases

The computationally efficient phase-screen forward modeling technique is extended to allow investigation of nonnormal raypaths. The code is developed to accommodate all diffracted and converted phases up to critical angle, building on a geometric construction method. The new approach relies upon prescanning the model space to assess the complexity of each screen. The propagating wavefields are then divided as a function of horizontal wavenumber, and each subset is transformed to the spatial domain separately, carrying with it angular information. This allows both locally accurate 3D phase corrections and Zoeppritz reflection and transmission coefficients to be applied. The phase-screen code is further developed to handle simple anisotropic media. During phase-screen modeling, propagation is undertaken in the wavenumber domain where exact expressions for anisotropic phase velocities are available. Traveltimes and amplitude effects from a range of anisotropic shales are computed and compared with previous published results.

Reflection and Transmission Coefficients of Plane Waves in Magnetoelectroelastic Layered Structures

2008 ◽  
Vol 130 (3) ◽  
Author(s):  
J. Y. Chen ◽  
H. L. Chen ◽  
E. Pan
Keyword(s):  
Piezoelectric Materials ◽  
Plane Waves ◽  
Layered Structures ◽  
Organic Glass ◽  
Reflection And Transmission Coefficients ◽  
Material Structure ◽  
Layered System ◽  
Reflection And Transmission ◽  
Transmission Coefficients ◽  
Novel Material

Reflection and transmission coefficients of plane waves with oblique incidence to a multilayered system of piezomagnetic and/or piezoelectric materials are investigated in this paper. The general Christoffel equation is derived from the coupled constitutive and balance equations, which is further employed to solve the elastic displacements and electric and magnetic potentials. Based on these solutions, the reflection and transmission coefficients in the corresponding layered structures are subsequently obtained by virtue of the propagator matrix method. Two layered examples are selected to verify and illustrate our solutions. One is the purely elastic layered system composed of aluminum and organic glass materials. The other layered system is composed of the novel magnetoelectroelastic material and the organic glass. Numerical results are presented to demonstrate the variation of the reflection and transmission coefficients with different incident angles, frequencies, and boundary conditions, which could be useful to nondestructive evaluation of this novel material structure based on wave propagations.

scholarly journals Propagation Characteristics of Oblique Incident Terahertz Wave in Nonuniform Dusty Plasma

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Yunhua Cao ◽  
Haiying Li ◽  
Zhe Wang ◽  
Zhensen Wu
Keyword(s):  
Dusty Plasma ◽  
Terahertz Wave ◽  
Dust Particles ◽  
Number Density ◽  
Propagation Characteristics ◽  
Absorption Coefficients ◽  
Reflection And Transmission ◽  
Transmission Coefficients ◽  
Propagation Matrix ◽  
Transmission And Absorption

Propagation characteristics of oblique incident terahertz wave from the nonuniform dusty plasma are studied using the propagation matrix method. Assuming that the electron density distribution of dusty plasma is parabolic model, variations of power reflection, transmission, and absorption coefficients with frequencies of the incident wave are calculated as the wave illuminates the nonuniform dusty plasma from different angles. The effects of incident angles, number density, and radius of the dust particles on propagation characteristics are discussed in detail. Numerical results show that the number density and radius of the dust particles have very little influences on reflection and transmission coefficients and have obvious effects on absorption coefficients. The terahertz wave has good penetrability in dusty plasma.

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