Comparison of the low-frequency variations of the vertical and horizontal components of the electric background field at the sea bottom

Geophysics ◽  
2012 ◽  
Vol 77 (6) ◽  
pp. E391-E396 ◽  
Author(s):  
Eirik G. Flekkøy ◽  
Endre Håland ◽  
Knut Jørgen Måløy
Keyword(s):  
Electric Field ◽  
Power Spectra ◽  
Low Frequency ◽  
Background Field ◽  
Sea Bottom ◽  
Vertical Electric Field ◽  
The Difference ◽  
Natural Electric Field ◽  
Frequency Variations ◽  
Averaging Techniques

Natural electric field variations are measured at the sea bottom over long periods of time by means of stationary, vertical, and horizontal galvanic antennas. We compare the power spectra of the vertical and horizontal field components and the extent to which they may be reduced by standard averaging techniques. Although the raw spectra of the vertical and horizontal components do not differ greatly, the difference in the spectra after averaging is significantly greater. Most significantly, in the frequency range between 0.0005 and 0.03 Hz, this averaging scheme suppresses the vertical electric field component more strongly than the horizontal component.

On modeling airborne very low‐frequency measurements

Geophysics ◽  
1989 ◽  
Vol 54 (12) ◽  
pp. 1596-1606 ◽  
Author(s):  
Ari Poikonen ◽  
Ilkka Suppala
Keyword(s):  
Plane Wave ◽  
Electric Field ◽  
Numerical Models ◽  
Vertical Component ◽  
Low Frequency ◽  
Primary Field ◽  
Vertical Electric Field ◽  
Inhomogeneous Plane ◽  
Inhomogeneous Plane Wave ◽  
Attenuation Characteristics

Numerical models employed in ground VLF modeling use a normally incident (homogeneous) plane wave as a primary field. We show that these models are not directly applicable to modeling the impedance and wavetilt in the air, quantities needed in the interpretation of airborne VLF resistivity measurements. Instead, the primary field must be replaced by an inhomogeneous plane wave incident on the ground at an angle close to 90 degrees in order to provide the correct behavior of the apparent resistivities in the air. VLF magnetic polarization parameters, however, can be modeled in the air using the normally incident plane wave as a primary field. We also show that the plane‐wave analysis provides the same attenuation characteristics for the wavetilt in the air that is predicted by the Norton’s surface wave obtained by using the vertical electric dipole as a source. Use of the inhomogeneous plane wave introduces the vertical component of the electric field in the model. A 2‐D modeling technique based on the network solution is used to demonstrate the effects of the vertical electric field in the H‐polarization case. The vertical electric field generates charge distributions on the horizontal boundaries of conductors. In the case of a vertical sheet‐like conductor, these charges cause a slight asymmetry in apparent‐resistivity anomalies. Attenuation characteristics of various VLF anomalies with altitude are also presented. The H‐polarization anomalies attenuate much more rapidly in the air than those for E‐polarization due to the difference in the dominating source of EM fields in each polarization.

On: “Ionospheric induced very low frequency electric field wavetilt changes” by D. V. Thiel and I. J. Chant (GEOPHYSICS, Jan., 1982, p. 60–62)

Geophysics ◽  
1984 ◽  
Vol 49 (8) ◽  
pp. 1388-1388
Author(s):  
James R. Wait
Keyword(s):  
Electric Field ◽  
Surface Impedance ◽  
Low Frequency ◽  
Impedance Measurement ◽  
Minor Role ◽  
Elliptical Polarization ◽  
Vertical Electric Field ◽  
A Minor ◽  
Ground Wave ◽  
Measuring Scheme

With all due respect to Singh and Rankin (1983), I believe that their criticism of the paper by Thiel and Chant (cited above) needs clarification. Contrary to the assertion by Singh and Rankin, the quoted formula for the function [Formula: see text] (incorrectly called a wavetilt) can indeed depend upon the mode of propagation. The factor sin θ, appearing in the quoted expressions, is the sine of the complex angle of the incident wave whether it be a ground wave or a downgoing ionospherically reflected wave. This point is central to the long‐standing dispute between the “Cagniard school” of magnetotelluric sounding and those who believe that source field characteristics can play a role. Thiel and Chant correctly pointed out that the elliptical polarization of the downgoing wave can mess up the results. But possibly they overlooked that this effect, in a surface impedance measurement, is minimized compared with a true wavetilt measurement. The latter senses the vertical electric field with a vertical (i.e., whip) antenna, whereas in a true surface impedance measuring scheme both horizontal E and horizontal H fields are sensed. Actually Thiel and Chant measured surface impedance, so the elliptical polarization of the downgoing wave probably plays a minor role.

scholarly journals Relationship between low-frequency electric-field fluctuations and ion conics around the cusp/cleft region

2006 ◽  
Vol 24 (2) ◽  
pp. 667-677
Author(s):  
W. Miyake ◽  
A. Matsuoka ◽  
T. Mukai
Keyword(s):  
Electric Field ◽  
Low Frequency ◽  
Low Energy ◽  
Integration Time ◽  
Field Fluctuations ◽  
The Difference ◽  
Field Lines ◽  
Local Intensity ◽  
The Relationship ◽  
Ion Conics

Abstract. We investigated the relationship between low-frequency (0.2-4.0 Hz) electric-field fluctuations (LEFs) and ion conics around the dayside cusp/cleft region in the altitude range from 5000 to 10000km from observations made by the Akebono satellite. Ion conics were generally associated with intense LEFs. We found a significant correlation between the power spectral density of LEFs at any frequency and the energy of simultaneously observed ion conics. Ion conics with a conic angle near 90 deg and those more aligned with magnetic field lines both had an equivalent correlation with the local intensity of the LEFs. The LEFs associated with near-perpendicular ion conics were, however, generally more intense than those associated with folded conics. The difference was clearer for low-energy conics. These results are in agreement with a scenario of height-integrated heating of ions and energization of ions by electromagnetic energy supplied by local LEFs. Ions generally stay in the energization region during their upward motion along the field line, so that more folded ion conics with weak energization reach the same energy level as near-perpendicular conics with strong energization, due to the difference in integration time. The limit on residence time in the intense heating region causes the clearer difference for low-energy conics. We set up a simple model to examine the relationship between the energization rate and the evolution of ion conics along the field lines, and obtained good agreement with the observation results.

Baroreflex stabilization of the double (pressure-rate) product at 0.05 Hz in conscious rabbits

2002 ◽  
Vol 282 (6) ◽  
pp. R1746-R1753 ◽  
Author(s):  
Bruce N. Van Vliet ◽  
Francesca Belforti ◽  
Jean-Pierre Montani
Keyword(s):  
Power Spectra ◽  
Low Frequency ◽  
Phase Relationship ◽  
Frequency Region ◽  
Spectral Coherence ◽  
Double Product ◽  
Frequency Peak ◽  
Conscious Rabbits ◽  
Frequency Variations ◽  
Prominent Peak

The product of heart rate (HR) and systolic blood pressure (SBP), the double product (DP), is an indirect index of cardiac oxygen consumption. We used spectral analysis to test the hypothesis that baroreflex adjustments of HR stabilize the DP during spontaneous variations in SBP. SBP and HR were recorded by telemetry in five male conscious rabbits. HR and SBP power spectra each exhibited a low frequency peak at ∼0.05 Hz that was associated with high (>0.5) spectral coherence and a positive phase relationship between SBP and HR (SBP leading). A prominent peak was absent in the spectra of their product, suggesting that SBP and HR interacted to reduce DP variability in this frequency region. In contrast, a prominent 0.05-Hz peak was present in the power spectrum of calculated surrogates of the DP in which reflex interactions between HR and SBP had been removed. Our results suggest that baroreflex adjustments of HR stabilize the DP during spontaneous low-frequency variations in SBP in conscious rabbits.

Development of a Low Frequency Electric Field Probe Integrating Data Acquisition and Storage

2020 ◽  
Vol E103.C (8) ◽  
pp. 345-352
Author(s):  
Zhongyuan ZHOU ◽  
Mingjie SHENG ◽  
Peng LI ◽  
Peng HU ◽  
Qi ZHOU
Keyword(s):  
Electric Field ◽  
Data Acquisition ◽  
Low Frequency ◽  
Frequency Electric Field ◽  
Electric Field Probe ◽  
And Storage

PEMANFAATAN RADIASI ENERGI TEGANGAN 150 KV UNTUK LAMPU LED PENERANGAN JALAN

Jurnal Teknik ◽  
2018 ◽  
Vol 7 (1) ◽  
Author(s):  
Mauludi Manfaluthy
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
High Voltage ◽  
Low Frequency ◽  
Energy Utilization ◽  
World Health ◽  
Electromagnetic Signals ◽  
Health Organization ◽  
The Magnetic Field ◽  
Low Frequency Waves

WHO (World Health Organization) concludes that not much effect is caused by electric field up to 20 kV / m in humans. WHO standard also mentions that humans will not be affected by the magnetic field under  100 micro tesla and that the electric field will affect the human body with a maximum standard of 5,000 volts per meter. In this study did not discuss about the effect of high voltage radiation SUTT (High Voltage Air Channel) with human health. The research will focus on energy utilization of SUTT radiation. The combination of electric field and magnetic field on SUTT (70-150KV) can generate electromagnetic (EM) and radiation waves, which are expected to be converted to turn on street lights around the location of high voltage areas or into other forms. The design of this prototype works like an antenna in general that captures electromagnetic signals and converts them into AC waves. With a capacitor that can store the potential energy of AC and Schottky diode waves created specifically for low frequency waves, make the current into one direction (DC). From the research results obtained the current generated from the radiation is very small even though the voltage is big enough.Keywords : Radiance Energy, Joule Thief, and  LED Module.

scholarly journals Focused Patterning of Electrospun Nanofibers Using a Dielectric Guide Structure

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1505
Author(s):  
Byeongjun Lee ◽  
Younghyeon Song ◽  
Chan Park ◽  
Jungmin Kim ◽  
Jeongbeom Kang ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Finite Elements ◽  
Electric Field ◽  
Electrospun Nanofibers ◽  
Electrospun Fibers ◽  
Continuous Line ◽  
Key Factors ◽  
Key Technology ◽  
Vertical Electric Field ◽  
Dielectric Guide

The patterning of electrospun fibers is a key technology applicable to various fields. This study reports a novel focused patterning method for electrospun nanofibers that uses a cylindrical dielectric guide. The finite elements method (FEM) was used to analyze the electric field focusing phenomenon and ground its explanation in established theory. The horizontal and vertical electric field strengths in the simulation are shown to be key factors in determining the spatial distribution of nanofibers. The experimental results demonstrate a relationship between the size of the cylindrical dielectric guide and that of the electrospun area accumulated in the collector. By concentrating the electric field, we were able to fabricate a pattern of less than 6 mm. The demonstration of continuous line and square patterning shows that the electrospun area can be well controlled. This novel patterning method can be used in a variety of applications, such as sensors, biomedical devices, batteries, and composites.

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