Perfect Plane Wave Source for Total-Field/Scattered-Field Formulation in FDTD using Time Domain Multipoint 1D Auxiliary Grid

2006 ◽  
Author(s):  
Tengmeng Tan ◽  
M. Potter
Keyword(s):  
Plane Wave ◽  
Time Domain ◽  
Scattered Field ◽  
Total Field ◽  
Wave Source

A 3-D Total-Field/Scattered-Field Plane-Wave Source for the FDTD Analysis of Reentry Plasma Sheath

2020 ◽  
Vol 68 (8) ◽  
pp. 6214-6225 ◽  
Author(s):  
Hailiang Wei ◽  
Yanming Liu ◽  
Lei Shi ◽  
Bo Yao ◽  
Xiaoping Li
Keyword(s):  
Plane Wave ◽  
Scattered Field ◽  
Plasma Sheath ◽  
Total Field ◽  
Wave Source ◽  
Field Plane

Fast plane-wave reverse time migration

Geophysics ◽  
2018 ◽  
Vol 83 (6) ◽  
pp. S549-S556 ◽  
Author(s):  
Xiongwen Wang ◽  
Xu Ji ◽  
Hongwei Liu ◽  
Yi Luo
Keyword(s):  
Time Delay ◽  
Plane Wave ◽  
Green’S Function ◽  
Green's Function ◽  
Time Domain ◽  
Reverse Time ◽  
Reverse Time Migration ◽  
Wave Source ◽  
Computation Cost ◽  
Time Migration

Plane-wave reverse time migration (RTM) could potentially provide quick subsurface images by migrating fewer plane-wave gathers than shot gathers. However, the time delay between the first and the last excitation sources in the plane-wave source largely increases the computation cost and decreases the practical value of this method. Although the time delay problem is easily overcome by periodical phase shifting in the frequency domain for one-way wave-equation migration, it remains a challenge for time-domain RTM. We have developed a novel method, referred as to fast plane-wave RTM (FP-RTM), to eliminate unnecessary computation burden and significantly reduce the computational cost. In the proposed FP-RTM, we assume that the Green’s function has finite-length support; thus, the plane-wave source function and its responding data can be wrapped periodically in the time domain. The wrapping length is the assumed total duration length of Green’s function. We also determine that only two period plane-wave source and data after the wrapping process are required for generating the outcome with adequate accuracy. Although the computation time for one plane-wave gather is twice as long as a normal shot gather migration, a large amount of computation cost is saved because the total number of plane-wave gathers to be migrated is usually much less than the total number of shot gathers. Our FP-RTM can be used to rapidly generate RTM images and plane-wave domain common-image gathers for velocity model building. The synthetic and field data examples are evaluated to validate the efficiency and accuracy of our method.

Perfect plane-wave source for a high-order symplectic finite-difference time-domain scheme

2011 ◽  
Vol 20 (11) ◽  
pp. 114701 ◽  
Author(s):  
Hui Wang ◽  
Zhi-Xiang Huang ◽  
Xian-Liang Wu ◽  
Xin-Gang Ren
Keyword(s):  
Finite Difference ◽  
Plane Wave ◽  
Time Domain ◽  
Finite Difference Time Domain ◽  
High Order ◽  
Wave Source ◽  
Difference Time

An inverse scattering technique for electromagnetic bistatic scattering

1969 ◽  
Vol 47 (11) ◽  
pp. 1177-1184 ◽  
Author(s):  
V. H. Weston ◽  
W. M. Boerner
Keyword(s):  
Plane Wave ◽  
Scattered Field ◽  
Convex Surface ◽  
The Body ◽  
Total Field ◽  
Convex Shape ◽  
Plane Wave Incident ◽  
Smooth Body ◽  
Equivalent Sources ◽  
The Fourier Transform

It is shown that the total field produced by a plane wave incident upon a scattering body can be expressed at all points in space as the sum of the incident field and the Fourier transform of a quantity which is related to the scattering matrix. For points exterior to the minimum convex surface enclosing the body, the scattered field is reducible to a plane-wave representation which requires knowledge of the bistatic scattered field, for a fixed frequency and direction of incidence. It is shown that for certain cases, the resulting expression for the bistatic scattered field may be employed in interior portions of the minimum convex shape (including the body) in which case it represents the field arising from a set of equivalent sources. Alternative representations are also given. A technique is presented which yields the surface of a perfectly-conducting piecewise-smooth body from knowledge of the local total field. To achieve uniqueness, the technique must be applied for at least two different frequencies. Numerical results are presented which illustrate the technique.

On the Rayleigh assumption in scattering by a periodic surface

1969 ◽  
Vol 65 (3) ◽  
pp. 773-791 ◽  
Author(s):  
R. F. Millar
Keyword(s):  
Conformal Mapping ◽  
Plane Wave ◽  
Analytic Continuation ◽  
Critical Points ◽  
Scattered Field ◽  
Wave Scattering ◽  
Elliptic Partial Differential Equations ◽  
Total Field ◽  
Periodic Surface ◽  
Plane Wave Scattering

AbstractIn treating plane wave scattering by a periodic surface, Lord Rayleigh (10) assumed that the discrete, outgoing and evanescent plane wave representation for the scattered field was valid on the surface itself. Recently, this Rayleigh assumption has been questioned and criticized. For the surface y = b cos kx on which the total field vanishes, Petit and Cadilhac(8) have demonstrated its invalidity when Kb > 0·448. The present paper discusses scattering of a wave, incident from y > 0, by an analytic periodic surface y = f(x) ( – ∞ < x < ∞), and shows that the Rayleigh assumption is valid if and only if the solution can be continued analytically across the boundary at least to the line y = minf(x). Conformal mapping and results relating to the analytic continuation of solutions to elliptic partial differential equations reduce the problem to one involving the location of singularities and critical points of a potential Green's function. Provided that the perturbation of the surface from a plane is sufficiently gentle, the validity of the Rayleigh assumption is established. For the surface y = b cos kx it is shown that the assumption is valid if Kb < γ, where γ is a positive number no greater than 0·448, the precise value of which is unknown. Possible extensions of the analysis to different or more general situations are suggested.

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