Prevailing-frequency approximation of the coupling ray theory for electromagnetic waves or elastic S waves

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F16%3A10331043" target="_blank" >RIV/00216208:11320/16:10331043 - isvavai.cz</a>

Výsledek na webu

<a href="http://dx.doi.org/10.1007/s11200-014-1070-4" target="_blank" >http://dx.doi.org/10.1007/s11200-014-1070-4</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1007/s11200-014-1070-4" target="_blank" >10.1007/s11200-014-1070-4</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Prevailing-frequency approximation of the coupling ray theory for electromagnetic waves or elastic S waves

Popis výsledku v původním jazyce

The coupling-ray-theory tensor Green function for electromagnetic waves or elastic S waves is frequency dependent, and is usually calculated for many frequencies. This frequency dependence represents no problem in calculating the Green function, but may represent a great problem in storing the Green function at the nodes of dense grids, typical for applications such as the Born approximation. This paper is devoted to the approximation of the coupling-ray-theory tensor Green function, which practically eliminates this frequency dependence within a reasonably broad frequency band. In the vicinity of a given prevailing frequency, we approximate the frequency-dependent frequency-domain coupling-ray-theory tensor Green function by two dyadic Green functions corresponding to two waves described by their travel times and amplitudes calculated for the prevailing frequency. We refer to these travel times and amplitudes as the coupling-ray-theory travel times and the coupling-ray-theory amplitudes. This "prevailing-frequency approximation" of the coupling ray theory for electromagnetic waves or elastic S waves allows us to process the coupling-ray-theory wave field in the same way as the anisotropic-ray-theory wave field. This simplification may be decisive when storing the tensor Green function at the nodes of dense grids, which is typical for applications such as the Born approximation. We test the accuracy of the proposed prevailing-frequency approximation of the coupling ray theory numerically using elastic S waves in eight anisotropic velocity models. The additional inaccuracy introduced by the prevailing-frequency approximation is smaller than the inaccuracy of the standard frequency-domain coupling ray theory, and smaller than the additional inaccuracy introduced by many other approximations of the coupling ray theory.

Název v anglickém jazyce

Prevailing-frequency approximation of the coupling ray theory for electromagnetic waves or elastic S waves

Popis výsledku anglicky

The coupling-ray-theory tensor Green function for electromagnetic waves or elastic S waves is frequency dependent, and is usually calculated for many frequencies. This frequency dependence represents no problem in calculating the Green function, but may represent a great problem in storing the Green function at the nodes of dense grids, typical for applications such as the Born approximation. This paper is devoted to the approximation of the coupling-ray-theory tensor Green function, which practically eliminates this frequency dependence within a reasonably broad frequency band. In the vicinity of a given prevailing frequency, we approximate the frequency-dependent frequency-domain coupling-ray-theory tensor Green function by two dyadic Green functions corresponding to two waves described by their travel times and amplitudes calculated for the prevailing frequency. We refer to these travel times and amplitudes as the coupling-ray-theory travel times and the coupling-ray-theory amplitudes. This "prevailing-frequency approximation" of the coupling ray theory for electromagnetic waves or elastic S waves allows us to process the coupling-ray-theory wave field in the same way as the anisotropic-ray-theory wave field. This simplification may be decisive when storing the tensor Green function at the nodes of dense grids, which is typical for applications such as the Born approximation. We test the accuracy of the proposed prevailing-frequency approximation of the coupling ray theory numerically using elastic S waves in eight anisotropic velocity models. The additional inaccuracy introduced by the prevailing-frequency approximation is smaller than the inaccuracy of the standard frequency-domain coupling ray theory, and smaller than the additional inaccuracy introduced by many other approximations of the coupling ray theory.

Druh

J_x - Nezařazeno - Článek v odborném periodiku (Jimp, Jsc a Jost)

CEP obor

DC - Seismologie, vulkanologie a struktura Země

OECD FORD obor

—

Projekt

Výsledek vznikl pri realizaci vícero projektů. Více informací v záložce Projekty.

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2016

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Studia Geophysica et Geodaetica

ISSN

0039-3169

e-ISSN

—

Svazek periodika

60

Číslo periodika v rámci svazku

3

Stát vydavatele periodika

CZ - Česká republika

Počet stran výsledku

32

Strana od-do

419-450

Kód UT WoS článku

000382365100005

EID výsledku v databázi Scopus

2-s2.0-84978880010