Electric currents in the ionosphere - The conductivity

1953 ◽  
Vol 246 (913) ◽  
pp. 281-294 ◽  
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
Uniform Magnetic Field ◽  
Hall Current ◽  
Effective Conductivity ◽  
Polarization Field ◽  
Dynamo Theory ◽  
Electric Currents ◽  
Narrow Strip ◽  
The Earth

An earlier suggestion by Martyn that the effective conductivity of the ionosphere in the dynamo theory is enhanced by polarization of the Hall current is examined in quantitative detail. General expressions are given for the conductivities of a thin ionized sheet oriented at an angle to a uniform magnetic field. The effective conductivity of such a (spherical) sheet surrounding the earth is shown to be greater than either the Pedersen or the Hall conductivities. The variation of conductivity with latitude is calculated for the ionospheric level of maximum effective conductivity. Consideration is given to the height-integrated conductivity of the actual ionosphere, and effective values deduced. It is shown that the F 2 region will move bodily under the influence of the electric field from lower regions, thereby reducing its ability to shunt the Hall polarization field. The effective conductivity over most of the earth is found to be sufficient to satisfy Stewart’s dynamo theory. In a narrow strip at the equator the conductivity is enhanced, thereby accounting for the anomalously large magnetic variations found to occur in these regions.

The westward drift of the Earth's magnetic field

1950 ◽  
Vol 243 (859) ◽  
pp. 67-92 ◽  
Keyword(s):  
Magnetic Field ◽  
Secular Variation ◽  
Outer Part ◽  
Earth’S Magnetic Field ◽  
Dynamo Theory ◽  
The Core ◽  
The Earth ◽  
Earth's Magnetic Field ◽  
Harmonic Analyses ◽  
Westward Drift

The westward drift of the non-dipole part of the earth’s magnetic field and of its secular variation is investigated for the period 1907-45 and the uncertainty of the results discussed. It is found that a real drift exists having an angular velocity which is independent of latitude. For the non-dipole field the rate of drift is 0.18 ± 0-015°/year, that for the secular variation is 0.32 ±0-067°/year. The results are confirmed by a study of harmonic analyses made between 1829 and 1945. The drift is explained as a consequence of the dynamo theory of the origin of the earth’s field. This theory required the outer part of the core to rotate less rapidly than the inner part. As a result of electromagnetic forces the solid mantle of the earth is coupled to the core as a whole, and the outer part of the core therefore travels westward relative to the mantle, carrying the minor features of the field with it.

Variations of electrical characteristics of near-surface atmosphere of the Earth during magnetic storm

2020 ◽  
Author(s):  
Svetlana Riabova ◽  
Alexander Spivak
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
Magnetic Storms ◽  
Electrical Characteristics ◽  
Near Surface ◽  
Russian Academy Of Sciences ◽  
The Earth ◽  
Geosphere Dynamics ◽  
Academy Of Sciences ◽  
The Magnetic Field

<p>Temporal variations of the electric field in near-surface layer of the Earth are determined by many factors, among which strong disturbances of the magnetic field should be especially noted. Magnetic storms cause an increase in the ionospheric electric field, which leads to variations in the gradient of the electric field potential near the Earth's surface. We consider the effect of magnetic storms in variations in the electrical characteristics of the atmosphere at Geophysical observatory «Mikhnevo» of Sadovsky Institute of Geosphere Dynamics of Russian Academy of Sciences and at Center for geophysical monitoring of Moscow of Sadovsky Institute of Geosphere Dynamics of Russian Academy of Sciences. We used data from the continuous monitoring of three components of the magnetic field, vertical components of the atmospheric electric field and atmospheric current carried out in fair weather. Experimental data processing and analysis show that accompanying magnetic storms with geomagnetic K index more or equal 5 increased variations in the electric field and vertical atmospheric current are characterized by different morphological structures. It is currently difficult to interpret the data. Nevertheless, the research results can be of great help in the development and verification of theoretical and computational models for generating variations in the electric field as a result of strong geomagnetic disturbances.</p>

THE APPLICATION OF A FLUXGATE MAGNETOMETER TO AN AUTOMATIC ELECTRONIC DEGAUSSING SYSTEM

1961 ◽  
Vol 39 (9) ◽  
pp. 1357-1368 ◽  
Author(s):  
R. L. Graham ◽  
J. S. Geiger
Keyword(s):  
Magnetic Field ◽  
Magnetic Storm ◽  
Uniform Magnetic Field ◽  
Regulation System ◽  
Fluxgate Magnetometer ◽  
Current Regulation ◽  
Correction Signal ◽  
Electronic Circuitry ◽  
The Earth

The three-component fluxgate magnetometer developed by Serson has been adapted to provide continuous correction signals to the degaussing system of the Chalk River iron-free β-ray spectrometer. Improved electronic circuitry has been developed for the magnetometer which minimizes the zero error and reduces to < 10−4 gauss long-term drift caused by component aging. The degaussing coil arrangement used to generate uniform magnetic field components opposite to those of the earth is indicated and the current regulation system is described briefly. The method in which the magnetometer correction signal is introduced into the current regulators is shown and an example is given of the performance of this degaussing system during a magnetic storm.

scholarly journals Effect of a stochastic electric field on plasma confinement in FTU

2016 ◽  
Vol 31 (02) ◽  
pp. 1650005 ◽  
Author(s):  
Roberto Martorelli ◽  
Giovanni Montani ◽  
Nakia Carlevaro
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
Electric Field ◽  
Uniform Magnetic Field ◽  
Planck Equation ◽  
Plasma Confinement ◽  
Stochastic Field ◽  
Magnetically Confined ◽  
The Magnetic Field ◽  
Plasma Profile

We discuss a stochastic model for the behavior of electrons in a magnetically confined plasma having axial symmetry. The aim of the work is to provide an explanation for the density limit observed in the Frascati Tokamak Upgrade (FTU) machine. The dynamical framework deals with an electron embedded in a stationary and uniform magnetic field and affected by an orthogonal random electric field. The behavior of the average plasma profile is determined by the appropriate Fokker–Planck equation associated to the considered model and the disruptive effects of the stochastic electric field are shown. The comparison between the addressed model and the experimental data allows to fix the relevant spatial scale of such a stochastic field. It is found to be of the order of the Tokamak micro-physics scale, i.e. few millimeters. Moreover, it is clarified how the diffusion process outlines a dependence on the magnetic field as [Formula: see text].

scholarly journals Computational Programming as a Tool in the Teaching of Electromagnetism in Engineering Courses: Improving the Notion of Field

2019 ◽  
Vol 9 (1) ◽  
pp. 64 ◽  
Author(s):  
J. Nogueira ◽  
Ricardo Alves ◽  
P. Marques
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
Electrical Engineering ◽  
Electric Currents ◽  
Positive Effects ◽  
Computational Methodology ◽  
The University ◽  
Students Satisfaction ◽  
Computational Programming ◽  
Energy Engineering

In this study we have attempted, firstly, to describe programming protocols developed for the teaching of an Electromagnetism course in the university degrees of Electrical Engineering and Energy Engineering, and secondly, to evaluate students’ satisfaction with the simulation practices through MATLAB® programming. The main objective of the protocols is to allow students to model and visualize the electric field and magnetic field (both static) and understand the approximation that is made when considering certain distributions of electric charges and electric currents. To evaluate the usefulness of this computational methodology, eighteen students from the two engineering degrees answered a questionnaire with seven questions related to the Electromagnetism course and to the benefits of using computer programming. Their answers are measured by a Likert scale. From the analysis of the results, we can conclude, in a general way, that the use of this methodology has positive effects in the learning of Electromagnetism in these two degrees.

Regular Motions in the Ionosphere: Electric and Magnetic Relationships

1961 ◽  
Vol 42 (2) ◽  
pp. 85-100 ◽  
Author(s):  
Sydney Chapman
Keyword(s):  
Magnetic Field ◽  
Electric Current ◽  
Electron Density ◽  
Geomagnetic Field ◽  
Sunspot Cycle ◽  
Ionospheric Currents ◽  
Electric Currents ◽  
Dynamo Action ◽  
Ionospheric Electron Density ◽  
The Earth

Regular worldwide motions in the ionosphere produce daily varying currents there by dynamo action in association with the geomagnetic field. The changing field of these currents induces electric currents within the earth. At the earth's surface, the combined magnetic field of these currents is measured. The parts of primary and secondary origin can be determined separately. The form and intensity of the ionospheric currents can be found. Their height is inferred from the study of the ionospheric electron density and conductivity; it can also be measured by rockets. The daily varying airflow in the layer bearing the electric current, at heights from about 90 to 125 km, can to some extent be inferred. The motion is due partly to the sun's thermal and tidal action and partly to the moon's tidal action. Many aspects of the magnetic variations and the inferred ionospheric motions are considered in some detail, especially their seasonal and sunspot-cycle changes and their variations from day to day.

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