Conduction Current and Displacement Current

2015 ◽  
pp. 81-99
Author(s):  
Pierre Maurice Marie Duhem
Keyword(s):  
Displacement Current ◽  
Conduction Current

scholarly journals Effect of Displacement Current on the Finite-Difference Modeling of Natural Source Electromagnetic Diffusion

2020 ◽  
Vol 10 (8) ◽  
pp. 2744
Author(s):  
Yahui Xue ◽  
Jianxin Liu ◽  
Rong Liu ◽  
Zhuo Liu ◽  
Rongwen Guo ◽  
...  
Keyword(s):  
Finite Difference ◽  
Displacement Current ◽  
Low Frequencies ◽  
Static Approximation ◽  
Conduction Current ◽  
Quasi Static Approximation ◽  
Modeling Accuracy ◽  
Em Field ◽  
Displacement Currents ◽  
Earth Conductivity

For electromagnetic (EM) modeling based on the electric-field formulation at low frequencies, the quasi-static approximation (i.e., only the conduction current is considered and the displacement current is ignored) is commonly applied, and a small conductivity value for the air layer is chosen subjectively. Actually, in the air layer, due to the use of the small conductivity value, the quasi-static approximation is ubiquitously violated. However, the effect of the violation of the quasi-static approximation in the air on EM modeling is not well examined in the literature. In this paper, we investigate this issue by comparing the finite-difference modeling results from the calculation with the quasi-static approximation and those considering both the conduction and displacement currents. For the quasi-static approximation, the conductivity in the air is set to be different small values, and zero air conductivity is used for the modeling with both the conduction and displacement currents considered. Several simple models are designed to verify the numerical solution and study how the assigned conductivity for the air affects the modeling accuracy. One flat model and two models with topography are designed to examine the effect of the quasi-static approximation on the EM modeling results. For frequencies used in typical geophysical applications of EM diffusion, using the quasi-static approximation is able to produce accurate modeling results for models with typical earth conductivity. However, if the rough surface topography is considered, the use of the quasi-static approximation can reduce the EM modeling accuracy substantially at much lower frequencies (as low as several hundred Hz), which is probably due to the inaccurate description of EM waves in the air, and poses problems for applications based on direct EM field interpretation.

AN ELECTRICAL CREVASSE DETECTOR

Geophysics ◽  
1956 ◽  
Vol 21 (4) ◽  
pp. 1055-1070 ◽  
Author(s):  
John C. Cook
Keyword(s):  
Department Of Defense ◽  
Displacement Current ◽  
Geophysical Method ◽  
Current Field ◽  
Conduction Current ◽  
Capacitance Method ◽  
Mutual Capacitance ◽  
Potential Applications ◽  
Electrode Method ◽  
Mineral Prospecting

Numerous fatal encounters with large crevasses concealed by bridges of drifted snow have occurred on the Greenland icecap and elsewhere. In response to an urgent need for rapid and reliable means of crevasse detection, a promising geophysical method has now been developed for the Department of Defense. This method is analogous to the four‐electrode method of measuring earth resistivities. It is different in that an alternating dielectric displacement‐current field is employed rather than a field of conduction current since the ice medium is essentially a nonconductor. As a result, basic differences in technique are necessary. The systems tested in Greenland and Antarctica, to date, which employ this method, continuously indicate or record the capacitive transfer reactance between pairs of electrode sleds or vehicles. Systems have been operated successfully while in motion at surface speeds up to 20 miles per hour. Pronounced and distinctive electrical anomalies have been obtained at every crevasse tested to date. Typical crevasse‐detector recordings and details of the equipment and techniques used are presented. Some potential applications of the mutual‐capacitance method in mineral prospecting and other fields are suggested.

IMPROVEMENT OF THE RESPONSE TIME FOR ORGANIC PHOTODETECTORS BY USING DISPLACEMENT CURRENT

2012 ◽  
Vol 26 (16) ◽  
pp. 1250100 ◽  
Author(s):  
BO LI
Keyword(s):  
Response Time ◽  
Organic Semiconductors ◽  
High Speed ◽  
Carrier Mobility ◽  
Displacement Current ◽  
Conduction Current ◽  
Organic Photodetector ◽  
Nanosecond Pulse Laser ◽  
Organic Photodetectors ◽  
Organic Dielectric

A new method is proposed to improve the response time of organic photodetectors by using displacement current. By inserting a transparent organic dielectric layer between the organic semiconductor active layer and the electrode the displacement current will be produced and replace the conduction current for current propagation, which will overcome the disadvantage of low carrier mobility of organic semiconductors. Under the irradiation of nanosecond pulse laser the rise time and fall time of the organic photodetector based on displacement current decrease 10% and 86%, respectively comparing to the conventional organic photodetector based on conduction current, which indicates the displacement current could renew the operation principle for high-speed organic photodetectors.

Numerical Simulation of Leakage Current on Conductive Insulator Surface

2019 ◽  
Vol 8 (4) ◽  
pp. 9487-9492
Keyword(s):  
Numerical Simulation ◽  
Electric Field ◽  
Leakage Current ◽  
Method Of Lines ◽  
Electron Attachment ◽  
Negative Ions ◽  
Conduction Current ◽  
Insulator Surface ◽  
Finite Difference Approximations ◽  
Positive Ions

The outdoor insulator is commonly exposed to environmental pollution. The presence of water like raindrops and dew on the contaminant surface can lead to surface degradation due to leakage current. However, the physical process of this phenomenon is not well understood. Hence, in this study we develop a mathematical model of leakage current on the outdoor insulator surface using the Nernst Planck theory which accounts for the charge transport between the electrodes (negative and positive electrode) and charge generation mechanism. Meanwhile the electric field obeys Poisson’s equation. Method of Lines technique is used to solve the model numerically in which it converts the PDE into a system of ODEs by Finite Difference Approximations. The numerical simulation compares reasonably well with the experimental conduction current. The findings from the simulation shows that the conduction current is affected by the electric field distribution and charge concentration. The rise of the conduction current is due to the distribution of positive ion while the dominancy of electron attachment with neutral molecule and recombination with positive ions has caused a significant reduction of electron and increment of negative ions.

Generation of Maxwell displacement current from spread monolayers containing azobenzene

1992 ◽  
Vol 72 (4) ◽  
pp. 1631-1636 ◽  
Author(s):  
Mitsumasa Iwamoto ◽  
Yutaka Majima ◽  
Haruhiko Naruse ◽  
Keiji Iriyama
Keyword(s):  
Displacement Current ◽  
Maxwell Displacement Current
Sign in / Sign up

Export Citation Format

Share Document