POTENTIAL AND APPARENT RESISTIVITY OVER DIPPING BEDS

Geophysics ◽  
1956 ◽  
Vol 21 (3) ◽  
pp. 780-793 ◽  
Author(s):  
Jerome Chastenet De Gery ◽  
Geza Kunetz
Keyword(s):  
Point Source ◽  
Current Density ◽  
Potential Field ◽  
Apparent Resistivity ◽  
Exact Expression ◽  
Electrode Configuration ◽  
Vertical Profiles ◽  
The Earth ◽  
Electrode Separation

The potential field due to a point source of current, located on the surface of the earth near a dipping bed, is given in an exact expression and modified expressions are developed for computations. These expressions lead to graphs of the potential field and to apparent resistivity vertical profiles which are presented. The Schlumberger electrode configuration is used. This configuration consists of two current electrodes and two potential electrodes, the latter placed close enough together that the current density between them can be considered to be uniform. With this configuration oriented perpendicular to the strike of the dipping bed, the apparent resistivity is paradoxical in that it approaches either zero or infinity as the electrode separation increases without limit.

APPARENT RESISTIVITY FOR DIPPING BEDS

Geophysics ◽  
1955 ◽  
Vol 20 (1) ◽  
pp. 123-139 ◽  
Author(s):  
Katsuro Maeda
Keyword(s):  
Differential Equation ◽  
Reflection Coefficient ◽  
Point Source ◽  
Electric Current ◽  
Potential Field ◽  
Apparent Resistivity ◽  
Computing Methods ◽  
Image Theory ◽  
The Earth ◽  
Dip Angle

The potential field of a point source of electric current, located on the surface of the earth above a dipping bed, is determined exactly by solving the appropriate differential equation. It is concluded that image theory is useful only in the two cases in which the reflection coefficient is plus one and the angle of dip is [Formula: see text] and in which the reflection coefficient is minus one and the dip angle is [Formula: see text] m being an integer. Computing methods are also developed for the cases in which the image theory is not applicable. Some numerical tables necessary for computation and several apparent resistivity curves are presented.

THREE‐LAYER RESISTIVITY CURVES FOR THE ELTRAN ELECTRODE CONFIGURATION

Geophysics ◽  
1940 ◽  
Vol 5 (1) ◽  
pp. 43-46 ◽  
Author(s):  
S. S. West
Keyword(s):  
Apparent Resistivity ◽  
Electrode Configuration ◽  
Published Data ◽  
Electrode Separation ◽  
Configuration Data

A method is described by which standard curves of apparent resistivity vs. electrode separation can be calculated for certain electrode configurations from the published data for the Wenner configuration. Data are given for plotting curves representing 15 sets of values of the three layer parameters in the case of the Eltran configuration.

scholarly journals Analysis of Electric Field and Current Density for Different Electrode Configuration of XLPE Insulation

2018 ◽  
Vol 7 (3.36) ◽  
pp. 127 ◽  
Author(s):  
Nishanthi Sunthrasakaran ◽  
Nor Akmal Mohd Jamail ◽  
Qamarul Ezani Kamarudin ◽  
Sujeetha Gunabalan
Keyword(s):  
Electric Field ◽  
Power System ◽  
Field Distribution ◽  
High Voltage ◽  
Current Density ◽  
Electric Field Distribution ◽  
Electrical Power ◽  
High Electric Field ◽  
Electrode Configuration ◽  
Maximum Electric Field

The most important aspect influencing the circumstance and characteristics of electrical discharges is the distribution of electric field in the gap of electrodes. The study of discharge performance requires details on the variation of maximum electric field around the electrode. In electrical power system, the insulation of high voltage power system usually subjected with high electric field. The high electric field causes the degradation performance of insulation and electrical breakdown start to occur. Generally, the standard sphere gaps widely used for protective device in electrical power equipment. This project is study about the electric field distribution and current density for different electrode configuration with XLPE barrier. Hence, the different electrode configuration influences the electric field distribution. This project mainly involves the simulation in order to evaluate the maximum electric field for different electrode configuration. Finite Element Method (FEM) software has been used in this project to perform the simulation. This project also discusses the breakdown characteristics of the XLPE. The accurate evaluation of electric field distribution and maximum electric field is an essential for the determination of discharge behavior of high voltage apparatus and components. The degree of uniformity is very low for pointed rod-plane when compared to other two electrode configurations. The non- uniform electric distribution creates electrical stress within the surface of dielectric barrier. As a conclusion, when the gap distance between the electrodes increase the electric field decrease.  

A TRI‐POTENTIAL METHOD OF RESISTIVITY PROSPECTING

Geophysics ◽  
1956 ◽  
Vol 21 (2) ◽  
pp. 455-469 ◽  
Author(s):  
E. W. Carpenter ◽  
G. M. Habberjam
Keyword(s):  
Apparent Resistivity ◽  
Potential Method ◽  
Electrode Configuration ◽  
Practical Application ◽  
Resistivity Method

This paper describes a method whereby three resistances are measured for a four electrode configuration, and relations between these three resistances and their corresponding apparent resistivities are derived. The practical application of the resistance relation as a means of detecting observational and instrumental errors is indicated. The concept of apparent resistivity is examined and by means of examples it is shown that the apparent resistivity can take negative values. Finally, the possibility of using the triple resistivity method as a means of distinguishing between the effects of lateral and vertical resistivity changes on depth probes is discussed.

A DISCUSSION OF THE “FAULT” AND “DIKE” PROBLEMS IN MAGNETOTELLURIC THEORY

Geophysics ◽  
1963 ◽  
Vol 28 (3) ◽  
pp. 487-490 ◽  
Author(s):  
J. T. Weaver
Keyword(s):  
Boundary Condition ◽  
Electromagnetic Wave ◽  
Current Density ◽  
Normal Component ◽  
The Earth ◽  
Source Field ◽  
Vertical Fault ◽  
Explicit Mention

In two recent papers appearing in Geophysics, d’Erceville and Kunetz (1962) and Rankin (1962) have dealt with the magnetotelluric theory for a plane earth which contains a certain type of vertical fault. In both cases the results depend on a boundary condition which requires the assumption that the normal component of current density vanishes at the surface of the earth. While d’Erceville and Kunetz confine their attention to the region below the surface and thereby avoid explicit mention of the source field, Rankin follows Cagniard (1953) by considering a plane‐polarized electromagnetic wave normally incident on the surface of the earth. In this case, the assumed boundary condition is not correct, as we shall see later; indeed, it actually leads to a contradiction.

PICASSO: The Golden CubeSat

2021 ◽  
Author(s):  
Noel Baker ◽  
Michel Anciaux ◽  
Philippe Demoulin ◽  
Didier Fussen ◽  
Didier Pieroux ◽  
...  
Keyword(s):  
Electron Temperature ◽  
Plasma Density ◽  
Space Science ◽  
Lessons Learned ◽  
Vertical Profiles ◽  
Proof Of Concept ◽  
Scientific Instruments ◽  
The Earth ◽  
Spacecraft Potential

<p>Led by the Belgian Institute for Space Aeronomy, the ESA-backed mission PICASSO (PICo-Satellite for Atmospheric and Space Science Observations) successfully launched its gold-plated satellite on an Arianespace Vega rocket in September 2020. PICASSO is a 3U CubeSat mission in collaboration with VTT Technical Research Center of Finland Ltd, AAC Clyde Space Ltd. (UK), and the CSL (Centre Spatial de Liège), Belgium. The commissioning of the two onboard scientific instruments is currently ongoing; once they are operational, PICASSO will be capable of providing scientific measurements of the Earth’s atmosphere. VISION, proposed by BISA and developed by VTT, will retrieve vertical profiles of ozone and temperature by observing the Earth's atmospheric limb during orbital Sun occultation; and SLP, developed by BISA, will measure in situ plasma density and electron temperature together with the spacecraft potential.</p><p>Serving as a groundbreaking proof-of-concept, the PICASSO mission has taught valuable lessons about the advantages of CubeSat technology as well as its many complexities and challenges. These lessons learned, along with preliminary measurements from the two instruments, will be presented and discussed.</p>

Offset‐dependent geometrical spreading in a layered medium

Geophysics ◽  
1990 ◽  
Vol 55 (4) ◽  
pp. 492-496 ◽  
Author(s):  
Bjørn Ursin
Keyword(s):  
Point Source ◽  
Taylor Series ◽  
Layered Medium ◽  
Exact Expression ◽  
Second Order ◽  
Geometrical Spreading ◽  
Approximate Expressions

The geometrical spreading for a point source in a horizontally layered medium has been computed by Ursin (1978) and Hubral (1978) as a Taylor series in the offset coordinate. The coefficients in the Taylor series depend on the thicknesses and the velocities of the layers. Here, I start with the exact expression for geometrical spreading and show that it can be expressed as a function of the velocity in the first layer, the offset, and the first‐ and second‐order traveltime derivatives. A shifted hyperbolic traveltime approximation (Castle, 1988) and the usual hyperbolic traveltime approximation are used to derive approximate expressions for geometrical spreading. These expressions can also be derived from a truncated Taylor series by making additional approximations, but this procedure is not so obvious.

On: “Correction of topographic distortions in potential‐field data: A fast and accurate approach” by Jianghai Xia, Donald R. Sprowl, and Dana Adkins‐Heljeson (April 1993 GEOPHYSICS, p. 515–523).

Geophysics ◽  
1993 ◽  
Vol 58 (12) ◽  
pp. 1874-1874
Author(s):  
David A. Chapin
Keyword(s):  
Point Source ◽  
Frequency Domain ◽  
Potential Field ◽  
Field Data ◽  
New Method ◽  
Potential Fields ◽  
Potential Field Data ◽  
Source Method ◽  
Equivalent Point ◽  
Breakthrough Technology

Xia et al. do an excellent job developing a new method for using the equivalent point source method in the frequency domain. The transformation from a varying datum to flat datum has always been a major problem in potential fields data. This is because the existing methods to perform this transformation have tended to be cumbersome, time‐consuming, and expensive. I congratulate the authors for this breakthrough technology.

Study on the Influence of Electrode Collocation to Electric Field Characteristic of ESP

2014 ◽  
Vol 875-877 ◽  
pp. 1683-1686
Author(s):  
Cheng Liang Jia ◽  
You Shan Sun ◽  
Chao Huang ◽  
Wan Peng Zhang ◽  
Fang Chen
Keyword(s):  
Electric Field ◽  
Current Density ◽  
Surface Current ◽  
Electrode Configuration ◽  
Electrode Gap ◽  
Average Current Density ◽  
Surface Current Density ◽  
Discharge Electrode ◽  
Field Characteristic ◽  
Average Current

A laboratory-scale ESP with new electrode configuration was established to investigate the electric field characteristic. Eight teeth prick line and prick plate with the length of 20mm were employed as discharge electrodes, respectively. The effects of discharge electrode type and electrode gap on V-I characteristic and surface current density were studied. The results showed that the optimum electrode gaps were 350-400mm for eight teeth line and 300-350mm for prick plate, which could obtained higher average current density and lower variance.

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