scholarly journals Terahertz Electric Field Driven Electric Currents and Ratchet Effects in Graphene

2017 ◽  
Vol 529 (11) ◽  
pp. 1600406 ◽  
Author(s):  
Sergey D. Ganichev ◽  
Dieter Weiss ◽  
Jonathan Eroms
Keyword(s):  
Electric Field ◽  
Electric Currents ◽  
Ratchet Effects

scholarly journals Electric Currents Connected With the Proton Flares of 7 July and 2 September, 1966

1971 ◽  
Vol 43 ◽  
pp. 417-421
Author(s):  
A. B. Severny
Keyword(s):  
Active Region ◽  
Field Strength ◽  
Magnetic Flux ◽  
Electric Field ◽  
Electric Field Strength ◽  
Electric Conductivity ◽  
Electric Current ◽  
Current Density ◽  
High Energy ◽  
Electric Currents

It is observed that the change of the net magnetic flux associated with flares can exceed 1017 Mx/s, which corresponds according to Maxwell's equation to the e.m.f. ∼ 109 V which is specific for the high energy protons generated in flares. It is shown that this value of e.m.f. can hardly be compensated by e.m.f. of inductance which should appear due to the actually measured motions in a flare generating active region. The values of electric field strength thus found, together with measured values of electric current density (from rotH), leads to an electric conductivity which is 103 times smaller than usually adopted.

Electric currents in the ionosphere - The atmospheric dynamo

1953 ◽  
Vol 246 (913) ◽  
pp. 295-305 ◽  
Keyword(s):  
Electric Field ◽  
Current System ◽  
Air Flow ◽  
Hall Conductivity ◽  
Equatorial Zone ◽  
Electric Currents ◽  
Field System ◽  
Polar Caps ◽  
Magnetic Variation ◽  
East West

Assuming semi-diurnal tidal air flow a solution is made of the atmospheric dynamo problem, taking account both of the direct and transverse conductivities of the ionosphere. The spherical sheet ionosphere is divided into three regions, a narrow equatorial zone, and two wide polar caps, taking appropriate constant conductivities in each region. The current system is similar in shape and phase to that derived on the assumption of uniform (direct) isotropic conductivity, but is considerably more intense than that which would be obtained without the existence of transverse (Hall) conductivity. The electric field system is very different, however, from that derived on this (isotropic) assumption. An abnormally large east-west current is found at the equator, which appears to provide the explanation of the anomalous magnetic variation in this region. Curves are given showing the distribution of the field and current components.

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.

THE MIGRATION OF FUNGAL NUCLEI IN AN ELECTRIC FIELD

1942 ◽  
Vol 20c (2) ◽  
pp. 92-100 ◽  
Author(s):  
E. S. Dowding ◽  
E. H. Gowan
Keyword(s):  
Electric Field ◽  
Electric Current ◽  
Mycelial Growth ◽  
Nuclear Migration ◽  
Normal Direction ◽  
The Other ◽  
Electric Currents ◽  
Pass Through ◽  
Neurospora Tetrasperma

The mycelium of Neurospora tetrasperma readily conducts an electric current. During the time an electric current of about 5 μa. is allowed to pass through cultures of N. tetrasperma or Gelasinospora tetrasperma, mycelial growth ceases almost entirely, but afterwards the fungi grow normally again and show no ill effects. Electric currents of the order of 1 or 10 μa. running in either direction through two fused strains of N. tetrasperma do not alter the normal direction of nuclear migration from one strain to the other.

Effect of small electric currents on intravascular thrombosis in the visualized rat mesentery

1960 ◽  
Vol 198 (5) ◽  
pp. 1006-1010 ◽  
Author(s):  
P. N. Sawyer ◽  
E. E. Suckling ◽  
S. A. Wesolowski
Keyword(s):  
Electric Field ◽  
Blood Vessels ◽  
Potential Drop ◽  
Potential Difference ◽  
Electric Currents ◽  
Ringer’S Solution ◽  
Intravascular Thrombosis ◽  
Rat Mesentery ◽  
Intravascular Occlusion

An experiment was designed to determine the effect of small electric currents on the blood vessels of the rat mesoappendix and mesentery, bathed with 1% gelatin Ringer's solution at temperature of 37° and pH 7.4. Current electrodes were applied to either edge of the rat mesoappendix. A potentiometric circuit was used to determine equipotential lines and transvascular potential differences. A dissecting microscope at 160x magnification was used to observe the rat mesoappendix. An electric field was created by the current passed. Total currents as small as 20 µa with a pole-to-pole potential difference of 20–30 mv maximum and a transvascular potential drop of 1–3 mv often resulted in intravascular occlusion of the vessels in the rat mesoappendix. The effective electric currents and their density were within the range of intensity attained by biologic injury currents. The possibility that injury currents in injured biologic tissues may be related to intravascular occlusion is discussed.

Electric currents in the ionosphere - Ionization drift due to winds and electric fields

1953 ◽  
Vol 246 (913) ◽  
pp. 306-320 ◽  
Keyword(s):  
Electric Field ◽  
Electric Current ◽  
Electric Fields ◽  
Body Force ◽  
Surrounding Medium ◽  
The Other ◽  
Electric Currents ◽  
Vertical Drift ◽  
Meteor Trails ◽  
Current Flows

An analysis is made of the drift velocity of the (neutral) ionization in a uniform ionosphere under the influences of an electric field and/or atmospheric wind. It is shown that this drift of ionization produces the Ampere body force on the medium; the electric current flows perpendicular to the drift. The motion of a cylinder of ionization, of density differing from the surrounding medium, is then studied. It is found that the motion is electrodynamically stable, but unstable hydrodynamically, if Hall conductivity is appreciable. In the latter event there is rapid accretion of (neutral) ionization on one side of the cylinder, depletion on the other. It is suggested that this is the origin of sporadic E ( E 5 )ionization, and is likely to be an important factor in the production of the long-enduring meteor trails detected by radio methods. Formulae are derived for the horizontal and vertical drift of ionization at all latitudes in a thin ionosphere in which vertical electric currents are prohibited by polarization. Graphs are given which permit derivation of the true wind or field in a given region of the ionosphere from experimental observations of the drift velocities.

Electric-field and temperature effects on electric currents in polycrystalline ZnGa2Se4

2010 ◽  
Vol 46 (2) ◽  
pp. 116-119
Author(s):  
A. N. Georgobiani ◽  
B. G. Tagiev ◽  
O. B. Tagiev ◽  
T. G. Kerimova ◽  
S. A. Abushov ◽  
...  
Keyword(s):  
Electric Field ◽  
Temperature Effects ◽  
Electric Currents

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.

A System for Measuring the Electric Field at the Ocean Floor

1972 ◽  
Vol 9 (7) ◽  
pp. 921-924 ◽  
Author(s):  
S. P. Srivastava
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
Recording System ◽  
Ocean Floor ◽  
Electric Currents ◽  
Scotian Shelf ◽  
The Magnetic Field

A self-contained recording system to measure the electric currents at the bottom of the ocean is described. The system was used to measure these currents on the Scotian Shelf south of Halifax, Canada. Comparison of the electric field recorded on the shelf with the magnetic field recorded at a shore based station show good correlation.

scholarly journals Generation of electric field in an earthquake preparation zone

1997 ◽  
Vol 40 (2) ◽  
Author(s):  
R. Teisseyre
Keyword(s):  
Electric Field ◽  
High Velocity ◽  
Earthquake Source ◽  
Source Zone ◽  
Displacement Current ◽  
Electric Currents ◽  
Current Generation ◽  
Anisotropic Properties ◽  
Earthquake Preparation ◽  
Velocity Motion

Different attempts have been made to explain the generation of the electric currents before an earthquake that take place in an earthquake preparation zone; in some of them the coseismic effects are also included. In this paper we discuss the possibility to construct a model of displacement current generation in an earthquake source zone which combines polarization processes and motion of charged dislocations. Such a process is associated with the transition from isotropic to stress-induced anisotropic properties in an earthquake source zone. Concurrently, we consider the conduction currents related to a high velocity motion of charged dislocations. Another approach related to an electrokinetic model of current generation is also briefly discussed.

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