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Article: Electromagnetic field of a dipole on a two-layer earth.

TitleElectromagnetic field of a dipole on a two-layer earth.
Authors
Issue Date1981
PublisherSociety of Exploration Geophysicists. The Journal's web site is located at http://scitation.aip.org/geophysics
Citation
Geophysics, 1981, v. 46 n. 3, p. 309-315 How to Cite?
AbstractThe electromagnetic field due to a horizontal electric dipole placed on top of a two-layer earth is represented in terms of fields due to a dipole over a half-space earth and its image source fields. Integral representations of image source fields are evaluated with uniform asymptotic approximations. Leading order ordinary saddle-point approximation, giving rise to the geometrical optics approximation (GOA), is shown to be inaccurate especially when the angle of observation is close to the critical angle, which corresponds to the presence of a branch-point singularity near the saddle point. In the uniform asymptotic approximation, the integrand of the image source integral is split into a branch-point free part and another part containing the branch-point singularity. The branch-point free part can be approximated with a spherical wave function, while the part containing the branch point can be approximated with parabolic cylinder functions. Vertical magnetic field components and the horizontal electric field component near the surface are illustrated and compared with the geometrical optics approximation, giving the direct numerical result as well as experimental measurement. It is shown that the uniform asymptotic approximation yields excellent agreement with numerical and experimental results compared to the geometrical optics approximation. -Authors
Persistent Identifierhttp://hdl.handle.net/10722/182459
ISSN
2015 Impact Factor: 2.017
2015 SCImago Journal Rankings: 1.646

 

DC FieldValueLanguage
dc.contributor.authorChew, WCen_US
dc.contributor.authorKong, JAen_US
dc.date.accessioned2013-05-02T05:15:27Z-
dc.date.available2013-05-02T05:15:27Z-
dc.date.issued1981en_US
dc.identifier.citationGeophysics, 1981, v. 46 n. 3, p. 309-315en_US
dc.identifier.issn0016-8033en_US
dc.identifier.urihttp://hdl.handle.net/10722/182459-
dc.description.abstractThe electromagnetic field due to a horizontal electric dipole placed on top of a two-layer earth is represented in terms of fields due to a dipole over a half-space earth and its image source fields. Integral representations of image source fields are evaluated with uniform asymptotic approximations. Leading order ordinary saddle-point approximation, giving rise to the geometrical optics approximation (GOA), is shown to be inaccurate especially when the angle of observation is close to the critical angle, which corresponds to the presence of a branch-point singularity near the saddle point. In the uniform asymptotic approximation, the integrand of the image source integral is split into a branch-point free part and another part containing the branch-point singularity. The branch-point free part can be approximated with a spherical wave function, while the part containing the branch point can be approximated with parabolic cylinder functions. Vertical magnetic field components and the horizontal electric field component near the surface are illustrated and compared with the geometrical optics approximation, giving the direct numerical result as well as experimental measurement. It is shown that the uniform asymptotic approximation yields excellent agreement with numerical and experimental results compared to the geometrical optics approximation. -Authorsen_US
dc.languageengen_US
dc.publisherSociety of Exploration Geophysicists. The Journal's web site is located at http://scitation.aip.org/geophysicsen_US
dc.relation.ispartofGeophysicsen_US
dc.titleElectromagnetic field of a dipole on a two-layer earth.en_US
dc.typeArticleen_US
dc.identifier.emailChew, WC: wcchew@hku.hken_US
dc.identifier.authorityChew, WC=rp00656en_US
dc.description.naturelink_to_subscribed_fulltexten_US
dc.identifier.scopuseid_2-s2.0-0019728597en_US
dc.identifier.volume46en_US
dc.identifier.issue3en_US
dc.identifier.spage309en_US
dc.identifier.epage315en_US
dc.publisher.placeUnited Statesen_US
dc.identifier.scopusauthoridChew, WC=36014436300en_US
dc.identifier.scopusauthoridKong, JA=7202290923en_US

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