Energetic characteristics of radiation of oscillating dipoles travelling in some dispersive and moving media

Author(s):  
E. G. Doil'nitsyna ◽  
A. V. Tyukhtin
Keyword(s):  
Geophysics ◽  
2010 ◽  
Vol 75 (5) ◽  
pp. 75A211-75A227 ◽  
Author(s):  
Kees Wapenaar ◽  
Evert Slob ◽  
Roel Snieder ◽  
Andrew Curtis

In the 1990s, the method of time-reversed acoustics was developed. This method exploits the fact that the acoustic wave equation for a lossless medium is invariant for time reversal. When ultrasonic responses recorded by piezoelectric transducers are reversed in time and fed simultaneously as source signals to the transducers, they focus at the position of the original source, even when the medium is very complex. In seismic interferometry the time-reversed responses are not physically sent into the earth, but they are convolved with other measured responses. The effect is essentially the same: The time-reversed signals focus and create a virtual source which radiates waves into the medium that are subsequently recorded by receivers. A mathematical derivation, based on reciprocity theory, formalizes this principle: The crosscorrelation of responses at two receivers, integrated over differ-ent sources, gives the Green’s function emitted by a virtual source at the position of one of the receivers and observed by the other receiver. This Green’s function representation for seismic interferometry is based on the assumption that the medium is lossless and nonmoving. Recent developments, circumventing these assumptions, include interferometric representations for attenuating and/or moving media, as well as unified representations for waves and diffusion phenomena, bending waves, quantum mechanical scattering, potential fields, elastodynamic, electromagnetic, poroelastic, and electroseismic waves. Significant improvements in the quality of the retrieved Green’s functions have been obtained with interferometry by deconvolution. A trace-by-trace deconvolution process compensates for complex source functions and the attenuation of the medium. Interferometry by multidimensional deconvolution also compensates for the effects of one-sided and/or irregular illumination.


1979 ◽  
Vol 36 (2) ◽  
pp. 230-262 ◽  
Author(s):  
H. L. Wilson ◽  
W. H. Scott, Jr. ◽  
G C. Pomraning

2000 ◽  
Vol 84 (5) ◽  
pp. 822-825 ◽  
Author(s):  
U. Leonhardt ◽  
P. Piwnicki

1979 ◽  
Vol 34 (10) ◽  
pp. 1147-1157 ◽  
Author(s):  
Helmut Hebenstreit ◽  
Kurt Suchy

Abstract For media anisotropic (but not bi-anisotropic) in the comoving frame polarization relations and dispersion equations are derived using bilinear forms and quadratic forms, respectively. Specializations for media electrically anisotropic but magnetically isotropic (or vice versa) are given using (left and right) eigenvectors and eigenvalues of the material tensors.


2006 ◽  
Vol 101 (5) ◽  
pp. 777-790 ◽  
Author(s):  
Yu. I. Heller

1964 ◽  
Vol 12 (3) ◽  
pp. 375-376 ◽  
Author(s):  
J. Collier ◽  
C. Tai
Keyword(s):  

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