Electric Field of a Charge Moving in a Medium

1963 ◽  
Vol 31 (8) ◽  
pp. 601-605 ◽  
Author(s):  
G. M. Volkoff
Keyword(s):  
Electric Field ◽  
A Charge

The vibration of electrified water drops

1971 ◽  
Vol 322 (1551) ◽  
pp. 523-534 ◽  
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Axial Ratio ◽  
Uniform Electric Field ◽  
Interferometric Technique ◽  
Photographic Analysis ◽  
Wide Range ◽  
Water Drops ◽  
Strength And Deformation ◽  
A Charge

Pressure has been used as the principal parameter in calculations of the fundamental vibrational frequencies of spherical drops of radius R , density ρ, and surface tension T carrying a charge Q or uncharged spheroidal drops of axial ratio a / b situated in a uniform electric field of strength E . Freely vibrating charged drops have a frequency f = f 0 ( 1 - Q 2 /16π R 3 T ) ½ , as shown previously by Rayleigh (1882) using energy considerations; f 0 is the vibrational frequency of non-electrified drops (Rayleigh 1879). The fundamental frequency of an uncharged drop in an electric field will decrease with increasing field strength and deformation a / b and will equal zero when E ( R )/ T ) ½ = 1.625 and a / b = 1.86; these critical values correspond to the disintegration conditions derived by Taylor (1964). An interferometric technique involving a laser confirmed the accuracy of the calculations concerned with charged drops. The vibration of water drops of radius around 2 mm was studied over a wide range of temperatures as they fell through electric fields either by suspending them in a vertical wind tunnel or allowing them to fall between a pair of vertical electrodes. Photographic analysis of the vibrations revealed good agreement between theory and experiment over the entire range of conditions studied even though the larger drops were not accurately spheroidal and the amplitude of the vibrations was large.

scholarly journals Electrostriction Effects During Defibrillation

2007 ◽  
Vol 6 (2) ◽  
Author(s):  
Michelle Fritz ◽  
Phil Prior ◽  
Bradley Roth
Keyword(s):  
Electric Field ◽  
Cardiac Tissue ◽  
Imaging Techniques ◽  
Stress And Strain ◽  
Mechanical Forces ◽  
Physical Origin ◽  
Anisotropic Cylinder ◽  
Simple Geometry ◽  
Complicated Manner ◽  
A Charge

Background—The electric field applied to the heart during defibrillation causes mechanical forces (electrostriction), and as a result the heart deforms. This paper analyses the physical origin of the deformation, and how significant it is. Methods—We represent the heart as an anisotropic cylinder. This simple geometry allows us to obtain analytical solutions for the potential, current density, charge, stress, and strain. Results—Charge induced on the heart surface in the presence of the electric field results in forces that deform the heart. In addition, the anisotropy of cardiac tissue creates a charge density throughout the tissue volume, leading to body forces. These two forces cause the tissue to deform in a complicated manner, with the anisotropy suppressing radial displacements in favor of tangential ones. Quantitatively, the deformation of the tissue is small, although it may be significant when using some imaging techniques that require the measurement of small displacements. Conclusions—The anisotropy of cardiac tissue produces qualitatively new mechanical behavior during a strong, defibrillation-strength electric shock.

scholarly journals Radio emission from polar caps in pulsars

1996 ◽  
Vol 160 ◽  
pp. 181-182
Author(s):  
Jan Kuijpers ◽  
Martin Volwerk
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Resonance Condition ◽  
Linear Acceleration ◽  
Stellar Atmospheres ◽  
Double Layers ◽  
Radio Pulsars ◽  
Polar Caps ◽  
Particle Speed ◽  
A Charge

Radiation from a charge accelerated along its path or Linear Acceleration Emission (LAE) involves a number of subtleties (Pauli 1921; Ginzburg 1970, 1989). Potential interest of the mechanism for astrophysics has been pointed out by Wagoner (1969). Melrose (1978) and Rowe (1995) have studied amplified LAE from time-varying electric fields for radio pulsars. In contrast with the latter work our calculations are for static electric field structures or double layers (DLs) as are thought to occur in magnetospheres of neutron stars. In ordinary stellar atmospheres a LAE maser can operate in non-relativistic DLs (Kuijpers 1990) at a frequencyω≈kDLυ≈ 2π/ttr, and a wave vectorwithkDL= 2π/L(Lis the DL length,υis the particle speed, andttris the transit time of the DL by the particle). The emission process can be considered as scattering of the electrostatic electric field on fast electrons into electromagnetic radiation satisfying the resonance condition:, when the frequency of the radiated mode in the frame of the emitting electron equals the Doppler shifted frequency of the electric field of the DL (DL wave frequencyωDL≈ 0). For relativistic DLs, as are applicable to pulsar magnetospheres, the emission is expected to be beamed under an angleθ≈γ−1and the frequency of emission boosted (ω≈kDLυ(1 −υcosθ/c)−1≈γ2kDLυ).

scholarly journals Nematic topological defects positionally controlled by geometry and external fields

2018 ◽  
Vol 9 ◽  
pp. 109-118 ◽  
Author(s):  
Pavlo Kurioz ◽  
Marko Kralj ◽  
Bryce S Murray ◽  
Charles Rosenblatt ◽  
Samo Kralj
Keyword(s):  
Electric Field ◽  
Topological Charge ◽  
Order Parameter ◽  
Topological Defects ◽  
Two Dimensional ◽  
External Fields ◽  
Nematic Ordering ◽  
Spatial Positioning ◽  
A Charge ◽  
The Impact

Using a Landau–de Gennes approach, we study the impact of confinement topology, geometry and external fields on the spatial positioning of nematic topological defects (TDs). In quasi two-dimensional systems we demonstrate that a confinement-enforced total topological charge of m > 1/2 decays into elementary TDs bearing a charge of m = 1/2. These assemble close to the bounding substrate to enable essentially bulk-like uniform nematic ordering in the central part of a system. This effect is reminiscent of the Faraday cavity phenomenon in electrostatics. We observe that in certain confinement geometries, varying the correlation length size of the order parameter could trigger a global rotation of an assembly of TDs. Finally, we show that an external electric field could be used to drag the boojum fingertip towards the interior of the confinement cell. Assemblies of TDs could be exploited as traps for appropriate nanoparticles, opening several opportunities for the development of functional nanodevices.

A Method to Calculate the Electric Field and Ion Current Density at Ground Level for HVDC Transmission Lines during Rain Weather

2013 ◽  
Vol 341-342 ◽  
pp. 1254-1260
Author(s):  
Zhao Zhi Long ◽  
Fei Lu
Keyword(s):  
Flow Field ◽  
Electric Field ◽  
Current Density ◽  
Transmission Lines ◽  
Ground Level ◽  
Ion Current ◽  
Hvdc Transmission ◽  
Hvdc Transmission Lines ◽  
A Charge ◽  
Ion Current Density

HVDC transmission lines can generate an effect on the environment nearby due to the electric field and the ion current density after the corona occurs, so the calculation of ionic flow field is significant to transmission lines design and electromagnetic analysis. However, there is no effective method to calculate the characteristic parameters of ionic flow field under rainy condition. Based on Deutschs assumption, a calculational method is proposed with considering the effects of raindrops on ionic flow field. In the method, the space-charge-free electric field distortion caused by raindrops is especially considered, and the charged raindrops are seen as a charge background of transmission lines. The field strengths and ion current densities calculated using this method are compared with the experimental results in the published literature, it shows that the method is effective and accurate enough under fair and rainy conditions.

scholarly journals The origin of the electrical charge on small particles in water

1926 ◽  
Vol 112 (760) ◽  
pp. 235-251 ◽  
Keyword(s):  
Electric Field ◽  
Bubble Surface ◽  
Electrical Charge ◽  
Potential Difference ◽  
New Method ◽  
Small Particles ◽  
Air Bubble ◽  
A Charge ◽  
As If

The surface of an air bubble is a particularly simple one at which to examine the electrical conditions which attend all small particles when immersed in a liquid. An air bubble may be considered as a type of coarse suspensoid, which, on being immersed in water, acquires a charge and moves in an electric field as if negatively electrified. The present work is a continuation of that already published ('Roy. Soc. Proc.,' A, vol. 106, p. 315 (1924)) and deals chiefly with the charge on the bubble immediately after it enters the liquid; this is examined experimentally and also theoretically. In addition, a new method of calculating the potential difference between the bubble surface and the interior of the liquid is suggested.

scholarly journals Photo- and electroluminescence of oxide-nitride-oxide-silicon structures for silicon-based optoelectronics

2018 ◽  
Vol 62 (5) ◽  
pp. 546-554
Author(s):  
I. A. Romanov ◽  
L. A. Vlasukova ◽  
F. F. Komarov ◽  
I. N. Parkhomenko ◽  
N. S. Kovalchuk ◽  
...  
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Silicon Oxide ◽  
Light Emission ◽  
Chemical Vapor ◽  
Nitride Layer ◽  
Silicon Oxynitride ◽  
Radiative Relaxation ◽  
A Charge ◽  
Nitride Oxide

Oxide-nitride-oxide-silicon (SiO2/SiN0.9/SiO2/Si) structures have been fabricated by chemical vapor deposition. The elemental composition and light emission properties of “SiO2/SiN0.9/SiO2/Si” structures have been studied using Rutherford backscattering spectroscopy (RBS), photo- and electroluminescence (Pl, El). The RBS measurements has shown the presence of an intermediate silicon oxynitride layers at the SiO2–SiN0.9 interfaces.It has been shown that the photoluminescence of the SiO2/SiN0.9/SiO2/Si structure is due to the emission of a SiN0.9 layer, and the electroluminescence is attributed to the emission of silicon oxide and oxynitride layers. A broad intense band with a maximum at 1.9 eV dominates the Pl spectrum. This band attributed to the radiative recombination of excited carriers between the band tail states of the SiN0.9 layer. The origin of the less intense Pl band at 2.8 eV is associated with the presence  of nitrogen defects in the silicon nitride.El was excited in the electrolyte-dielectric-semiconductor system. The electric field strength in the SiO2 layers reached 7–8 MV/cm and exceeded this parameter in nitride layer nearly four times. The electrons accelerating in electric field of 7–8 MV/cm could heat up to energies more than 5 eV. It is sufficient for the excitation of luminescence centres in the silicon oxide and oxynitride layers. The SiO2/SiN0.9/SiO2/Si composition El bands with quantum energies of 1.9 and 2.3 eV are related to the presence of silanol groups (Si–OH) and three-coordinated silicon atoms (≡Si•) in the silicon oxide layers. The El band with an energy of 2.7 eV is attributed to the radiative relaxation of silylene (O2=Si:) centers in the silicon oxynitride regions. It is observed the least reduction of this band intensity under the influence of strong electric fields after a charge flow  of 1–3 C/cm2.

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