TRANSIENT ELECTROMAGNETIC PROPAGATION IN A CONDUCTING MEDIUM

Geophysics ◽  
1951 ◽  
Vol 16 (2) ◽  
pp. 213-221 ◽  
Author(s):  
James R. Wait
Keyword(s):  
Magnetic Dipole ◽  
Electric Fields ◽  
Electric Dipole ◽  
Laplace Transformation ◽  
Step Function ◽  
Conducting Medium ◽  
Infinite Length ◽  
Electromagnetic Propagation ◽  
Transient Electromagnetic

The transient electric fields will be calculated for several types of step function current sources embedded in a conducting medium. These will be developed by the aid of the Laplace Transformation. The types of source elements considered are the electric dipole, the magnetic dipole and the linear grounded current element of finite and infinite length.

Discussions and Communications: Propagation of Transient Electromagnetic Waves in a Conducting Medium

Geophysics ◽  
1955 ◽  
Vol 20 (4) ◽  
pp. 959-961 ◽  
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Electromagnetic Waves ◽  
Step Function ◽  
Conducting Medium ◽  
Initial Value ◽  
Transient Electromagnetic ◽  
Ramp Function

Wait (1951) has calculated the transient electric fields for several types of step-function current sources placed inside a conducting medium. Now any generated pulse will require a finite build-up time to reach its final magnitude from its initial value of zero. In most cases, this type of pulse may be very well approximated by a ramp-function pulse (Figure 1). Expressions for the electric field of this type of pulse will be deduced in the following analysis.

Errata List for Papers in Geophysics by James R. Walt

Geophysics ◽  
1953 ◽  
Vol 18 (4) ◽  
pp. 973-973
Author(s):  
James R. Walt
Keyword(s):  
Conducting Medium ◽  
Electromagnetic Propagation ◽  
Transient Electromagnetic

I am herewith sending a list of typographical errors and omissions of several of my papers in Geophysics: “Transient Electromagnetic Propagation in a Conducting Medium” Vol. 16, pp. 213-222, 1951.

scholarly journals Electrostatic and magnetostatic fields of point dipoles revisited

2019 ◽  
Vol 65 (1) ◽  
pp. 71 ◽  
Author(s):  
Y. Muniz ◽  
Anderson José Fonseca ◽  
C. Farina
Keyword(s):  
Magnetic Dipole ◽  
Electric Dipole ◽  
Alternative Procedure ◽  
Dirac Delta ◽  
Delta Functions ◽  
Point Electric Dipole

After reviewing how the Dirac delta contributions to the electrostatic and magnetostatic fields of a point electric dipole and a point magnetic dipole are usually introduced, we present an alternative procedure for obtaining these terms based on a regularization prescription similar to that used in the computation of the transverse and longitudinal delta functions. We think this method may be useful for the students in other analogous calculations.

First application of the marine differential electric dipole for groundwater investigations: A case study from Bat Yam, Israel

Geophysics ◽  
2018 ◽  
Vol 83 (2) ◽  
pp. B59-B76 ◽  
Author(s):  
Amir Haroon ◽  
Klaus Lippert ◽  
Vladimir Mogilatov ◽  
Bülent Tezkan
Keyword(s):  
Electric Dipole ◽  
Coastal Region ◽  
Natural Phenomenon ◽  
The Novel ◽  
Aquifer System ◽  
Transient Electromagnetic ◽  
Long Offset ◽  
Lateral Extent ◽  
First Time

The marine differential electric dipole (DED) is applied for the first time to study a subseafloor groundwater body in the coastal region of Bat Yam, Israel. Previous marine long-offset transient electromagnetic applications detected this freshwater body underneath the Mediterranean seafloor. We have applied the novel DED method for the first time in the marine environment to further investigate this natural phenomenon. The main objectives are to locate the freshwater-seawater interface at the western aquifer edge and to identify the mechanism controlling this freshwater occurrence beneath the seafloor. The acquired step-on signals allow one to detect the freshwater body in the vicinity of the Israeli coastline at a depth of approximately 70 m beneath the seafloor. However, aquifer thickness is only poorly determined and may vary between 40 and 100 m. A lateral resistivity contrast is observable between adjacent 1D inversion models and also apparent in data profile curves that constrain the seaward extent of the detected resistive body to a distance of less than 4 km from the coastline. A subsequent 2.5D forward-modeling study aims to find a subseafloor resistivity distribution that adequately explains all measured DED data simultaneously. The results further constrain the lateral extent of the resistive aquifer to approximately 3.6–3.7 km from the Israeli coast. Furthermore, the data indicate that the aquifer system may be susceptible to seawater intrusion, as a superior data fit is achieved if a brackish water zone of approximately [Formula: see text] with a lateral extent of less than 300 m is located at the head of the freshwater body.

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