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.

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.

On Chip Micropumping for Biofluids by Temperature Biased AC Electrothermal Effect

2010 ◽  
Author(s):  
Jie Wu ◽  
Kai Yang ◽  
Quan Yuan
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Low Cost ◽  
Research Area ◽  
Pump Design ◽  
Temperature Bias ◽  
Mobile Charges ◽  
Current Flows ◽  
On Chip ◽  
Small Form Factor

For biofluids, very limited voltage can be applied without causing reactions, even with AC voltages, so conventional electrokinetic pumps cannot function effectively. Here two innovative ACEK micropump designs are proposed, which are expected to solve the long-standing problem of on-chip pumping for biofluids. This work focuses on exploiting external heat flux or temperature bias to enhance micropumping by AC electrothermal effect. AC electrothermal effect is ubiquitous as long as electric current flows through fluid. Investigating the interplay between electric field and temperature field will be useful for the research area of electrokinetics as a whole. New methods to enhance on chip micorpumping have been presented in this paper. Inhomogenous electric fields can cause uneven Joule heating of the fluid, which generates thermal gradients and leads to mobile charges in fluid bulk. The two pumping schemes circumvent the voltage problem by introducing extra thermal gradient to generate mobile charges. The free charges then move under the electric field and induce microflows due to viscosity. Numerical simulation and preliminary experiments have successfully demonstrated the improvement in flow velocity. It enriches the repertoire for the design of ACEK micropump, and affords us more flexibility when dealing with micropumping tasks. The micropumping mechanisms proposed here are simple, robust, of small form factor, can be readily integrated into microsystems at low cost. The proposed fabrication and micropump integration process is highly manufacturable with various materials and can be easily incorporated into a fully integrated biochip. The added design flexibility from this project will lend the pump design well towards many lab-on-a-chip applications.

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.

scholarly journals The influence of homodromous and heterodromous electric currents on transmission of excitation in plant and animal

1915 ◽  
Vol 88 (607) ◽  
pp. 483-507 ◽  
Keyword(s):  
Electric Current ◽  
The Other ◽  
Muscle Preparation ◽  
Mimosa Pudica ◽  
Electric Currents ◽  
Joint Effects ◽  
Conducting Tissue ◽  
The One ◽  
Conduction Of Excitation ◽  
Stimulation Of

I have in a previous paper described investigation on the conduction of excitation in Mimosa pudica . It was there shown that the various characteristics of the propagation of excitation in the conducting tissue of the plant are in every way similar to those in the animal nerve. Hence it appeared probable that any newly found phenomenon in the one case was likely to lead to the discovery of a similar phenomenon in the other. A problem of great interest which has attracted my attention my attention for several years is the question whether, in a conducting tissue, excitation travels better with or against the direction of an electric current. The experimental difficulties presented in the prosecution of this enquiry are very numerous, the results being complicated by the joint effects of the direction of current on conductivity and of the poles on excitability. As regards the latter, the changes of excitability in the animal nerve under electrotonus have been demonstrated by the well-known experiments of pflüger. In a nerve-and-muscle preparation, the presence of a pole P is shown to induce a variation of excitability of a neighbouring point S. When P is kathode, the excitability of the point S, near it, is enhanced; stimulation of S, previously ineffective, now becomes effective, and the resulting excitation is transmitted to M, causing response of the muscle. Conversely, the application of anode at P causes a depression of excitability of S. Stimulus previously effective now becomes ineffective. In this manner the transmission of excitation may be indirectly modified by the polar variation of excitability of the stimulated point (fig. 1 a ).

scholarly journals On line-integrals of the diurnal magnetic variations

1928 ◽  
Vol 119 (782) ◽  
pp. 182-196 ◽  
Keyword(s):  
Electric Current ◽  
Potential Gradient ◽  
Electromagnetic Theory ◽  
Magnetic Data ◽  
Magnetic Survey ◽  
Electric Currents ◽  
Direct Measurements ◽  
On Line ◽  
Current Densities ◽  
Current Flows

1. According to electromagnetic theory, the line-integral ∫ H . ds of the magnetic force H taken round any closed curve is equal to 4πI, where I is the electric current threading the curve, H and I being measured in c.g.s. units. Such line-integrals have been calculated by Gauss and many later investigators for various curves on the earth’s surface, in order to determine whether any electric current flows upwards or downwards across the surface. Modern computations for large areas lead in general to values of ∫ H . ds differing from zero by amounts that correspond to current-densities of the order 3·10 -2 ampere/km. 2 . The magnetic field of such currents would account for 2 or 3 per cent, of the earth’s surface field. These results are inconsistent with the direct measurements of the atmospheric electric potential gradient and the ionisation of the air, which indicate a verticalcurrent-density of the order 3·10 -6 amp./km. 2 . If the magnetic estimates are reliable, the discrepancy indicates either that atmospheric electric currents exist which escape measurement, though they are 10,000 times as great as those which are measured, or that the relation ∫ H . ds = 4πI, which is one of the foundations of electromagnetic theory, is not strictly correct. These alternatives are so remarkable that the magnetic evidence must be above suspicion if it is to gain credence. Dr. L. A. Bauer holds that the results got from independent sets of data, for different epochs, and the mutual accordance of the results from neighbouring areas, justify the acceptance of the non-zero line-integrals, and that to explain them away it is necessary to assume quite unlikely systematic errors in the magnetic data. Other investigators show less conviction: for example, Sir Frank Dyson and H. Furner conclude that “though there is some evidence for Prof. Bauer’s results, the existence of vertical electric currents is not indicated with any great certainty.” But though the magnetic evidence may not be conclusive, it cannot be lightly dismissed, and in view of the importance of the question Sir Arthur Schuster has recently urged the desirability of a detailed magnetic survey of a small area as the best means of obtaining a definite conclusion.

scholarly journals Equatorial night-time F-region zonal electric fields

1995 ◽  
Vol 13 (8) ◽  
pp. 871-878 ◽  
Author(s):  
S. S. Hari ◽  
B. V. Krishna Murthy
Keyword(s):  
Seasonal Variation ◽  
Electric Field ◽  
Electric Fields ◽  
Night Time ◽  
Equatorial Station ◽  
F Region ◽  
Vertical Drift ◽  
Longitudinal Gradients ◽  
Cycle Maximum ◽  
E Region

Abstract. Night-time F-region vertical electrodynamic drifts at the magnetic equatorial station, Trivandrum are obtained for a period of 2 years, 1989 and 1990 (corresponding to solar cycle maximum epoch), using ionosonde h'F data. The seasonal variation of the vertical drift is found to be associated with the longitudinal gradients of the thermospheric zonal wind. Further, the seasonal variation of the prereversal enhancement of the vertical drift is associated with the time difference between the sunset times of the conjugate E-regions (magnetic field line linked to F-region) which is indicative of the longitudinal gradients of the conductivity (of the E-region). The vertical drifts and the causative zonal electric fields at Trivandrum are compared with those at Jicamarca and F-region zonal electric field models. It is seen that the night-time downward drift (as also the causative westward electric field) at Jicamarca is greater than that at Trivandrum. The prereversal enhancement of the drift is greater at Jicamarca than at Trivandrum during the summer and the equinoxes, whereas during the winter the opposite is the case.

scholarly journals A Study of Possible Reasons of the Damage by Electric Current of Traction Induction Motors Bearings of Electric Trains Lastochka and the Ways to Prevent This

2021 ◽  
Vol 2096 (1) ◽  
pp. 012001
Author(s):  
M Pustovetov
Keyword(s):  
Electric Current ◽  
High Frequency ◽  
Induction Motors ◽  
Electrical Breakdown ◽  
The Other ◽  
Technical Solution ◽  
Insulation Coating ◽  
Rolling Elements ◽  
Current Flows ◽  
Frequency Current

Abstract There is a problem of damage of bearings of traction induction motors of electric trains Lastochka by electric current. Based on the fact that the bearings have a ceramic insulation coating, and the cases of its electrical breakdown is not fixed, the authors put forward a version that a high-frequency current flows through the bearing as through an electric capacitance. The analysis show that the cause of the current can be a radio standard GSM-R. The proposed technical solution against the damage of bearings: the use of grounding shaft rings, replace the bearings on the other with ceramic rolling elements, arrangement of separate high-frequency grounding for the GSM-R antenna.

Spatiotemporally resolved measurements of electric field around a piezoelectric transformer using electric-field induced second harmonic (E-FISH) generation

2021 ◽  
Author(s):  
Jinyu Yang ◽  
Ed V Barnat ◽  
Seong-kyun Im ◽  
David B. Go
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Second Harmonic ◽  
Surrounding Medium ◽  
Input Voltage ◽  
Piezoelectric Transformer ◽  
Power Sources ◽  
Plasma Generation ◽  
Distal Surface ◽  
The Face

Abstract When a piezoelectric transformer (PT) is actuated at its second harmonic frequency by a low input voltage, the generated electric field at the distal end can be sufficient to breakdown the surrounding gas, making them attractive power sources for non-equilibrium plasma generation. Understanding the potential and electric fields produced in the surrounding medium by the PT is important for effectively designing and using PT plasma devices. In this work, the spatiotemporally resolved characteristics of the electric field generated by a PT operating in open air have been investigated using the femtosecond electric field-induced second harmonic generation (E-FISH) method. Electric field components were determined by simultaneously conducting E-FISH measurements with the incident laser polarized in two orthogonal directions relative to the PT crystal. Results of this work demonstrate the spatial distribution of electric field around the PT’s output distal end and how it evolves as a function of time. Notably, the strongest electric field appears on the face of the PT’s distal surface, near the top and bottom edges and decreases by approximately 70% over 3 mm. The time delay between the PT’s input voltage and measured electric field indicates that there is an about 0.45 phase difference between the PT’s input voltage and output signal.

Ionospheric Irregularities During Disturbed Geomagnetic Conditions Over Argentinian EIA Region

2021 ◽  
Author(s):  
Gilda de Lourdes González
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Geomagnetic Storms ◽  
Ionospheric Irregularities ◽  
The Other ◽  
Scintillation Index ◽  
Navigation Systems ◽  
Radio Communication ◽  
Spread F ◽  
Bottom Side

Abstract Ionospheric irregularities can severely degrade radio communication and navigation systems. Geomagnetic storms may affect the generation of these irregularities in a way that is not yet fully understood. To improve the forecasting of this phenomenon, we need to study the ionosphere in different regions of the world, and in particular in the equatorial ionization anomaly (EIA) where irregularities are usually more intense. This study analyses the effect of geomagnetic storms on ionospheric irregularities. We examined the occurrence of irregularities at the southern crest of the EIA in Argentina (Tucumán, 26.9°S, 294.6°E, dip latitude 15.5° S) during three intense and one moderate geomagnetic storm of different solar sources, between 2015 and 2018. We used data from an ionosonde, a Global Positioning System (GPS) receiver and magnetometers. Ionogram spread-F, the F-layer bottom side (h'F), the critical frequency of the F2-layer (foF2), the rate of TEC index (ROTI) and the S4 scintillation index were analysed. The data show irregularities were present as range spread-F and moderate TEC fluctuations in one storm: 27 May 2017 (a coronal mass ejection CME-driven storm occurred on local winter), and were absent in the other events. We suggest that eastward disturbance dynamo electric field and over-shielding prompt penetration electric fields may create favourable conditions for developing these irregularities. Whereas, westward storm time electric fields might inhibit the growth of irregularities during the other storms considered. During co-rotating interaction region CIR-driven storms, the westward disturbance dynamo electric field may be associated with the non-occurrence of irregularities.

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