Electric field in media with power-law spatial dispersion

In this paper, we consider electric fields in media with power-law spatial dispersion (PLSD). Spatial dispersion means that the absolute permittivity of the media depends on the wave vector. Power-law type of this dispersion is described by derivatives and integrals of non-integer orders. We consider electric fields of point charge and dipole in media with PLSD, infinite charged wire, uniformly charged disk, capacitance of spherical capacitor and multipole expansion for PLSD-media.

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Dirac Spatial Search with Electric Fields

Entropy ◽

10.3390/e23111441 ◽

2021 ◽

Vol 23 (11) ◽

pp. 1441

Author(s):

Julien Zylberman ◽

Fabrice Debbasch

Keyword(s):

Dirac Equation ◽

Electric Field ◽

Time Scales ◽

Electric Fields ◽

Point Charge ◽

Quantum Walks ◽

Spatial Search ◽

Speed Up ◽

Finite Period ◽

Non Local

Electric Dirac quantum walks, which are a discretisation of the Dirac equation for a spinor coupled to an electric field, are revisited in order to perform spatial searches. The Coulomb electric field of a point charge is used as a non local oracle to perform a spatial search on a 2D grid of N points. As other quantum walks proposed for spatial search, these walks localise partially on the charge after a finite period of time. However, contrary to other walks, this localisation time scales as N for small values of N and tends asymptotically to a constant for larger Ns, thus offering a speed-up over conventional methods.

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CONTROLLED ELECTRIC FIELD-ASSISTED JETTING FROM VISCOUS AND NANOSUSPENSION MEDIA DROPLETS

NANO ◽

10.1142/s1793292006000252 ◽

2006 ◽

Vol 01 (03) ◽

pp. 243-250 ◽

Cited By ~ 1

Author(s):

S. N. JAYASINGHE

Keyword(s):

Electric Field ◽

Electric Fields ◽

Materials Science ◽

High Viscosity ◽

Copper Plate ◽

Direct Result ◽

Droplet Volume ◽

Droplet Deformation ◽

On Demand ◽

The Media

This paper reports a study into forming a jet-on-demand to continuous microthreads by subjecting electric fields on high viscosity and low conducting media (concentrated nanosuspensions and dielectric mediums) droplets, placed on a conducting copper plate, which has a similar plate above at a distance of ~ 10 mm. The media used in this investigation has a viscosity ≫ 1000 mPa s and an electrical conductivity ≪ 10-6 Sm-1 and in the case of nanomaterial loading in suspension is 003E; 15 wt.%. The investigation illustrates both the ability to form jets in this configuration and the importance of the volume of media placed as a droplet which has a direct result on the formation of a jet subsequently fragmentating to droplets. At a droplet volume of < Q0, the resting droplet when under the influence of an applied electric field deforms forming a cone, much like those referred to as the "Taylor Cones". On increasing the volume of the droplet to Q0 and applying a voltage of ~ 4.6 kV across the plates, the apex of the cone was observed to pulsate. On further increasing the applied voltage, giving rise to an electric field strength of ~ 0.55 kV/mm, the pulsating apex stabilizes to evolve a stable jet which undergoes instabilities promoting the generation of droplets. Consequently, a fine jet-on-demand is obtained. On increasing the droplet volume to > Q0, forms jets on both plates. The study elucidates the importance of this jetting approach for forming droplet relics containing self-assembled nanoparticles to continuous microthreads from concentrated nanosuspensions and dielectric media for forming structures by deposition that are most useful and have widespread applications in materials science and engineering. Hence, the physical behavior of this droplet deformation — jetting — forming droplets under an imposed field, outlines the discussion presented in this paper.

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Excitation and dissociation of hydrogen by an electron swarm

Proceedings of the Royal Society of London Series A - Mathematical and Physical Sciences ◽

10.1098/rspa.1958.0087 ◽

1958 ◽

Vol 245 (1242) ◽

pp. 335-351 ◽

Cited By ~ 50

Keyword(s):

Electric Field ◽

Electric Fields ◽

Ultra Violet ◽

Absolute Magnitude ◽

Uniform Electric Field ◽

Electrodeless Discharge ◽

Ultra Violet Radiation ◽

Excitation Coefficient ◽

The Absolute ◽

State 1

Electrons moving in a uniform electric field ionize and excite gas molecules and, for feeble swarm currents, are known to multiply exponentially with distance. The rate of quantum production can therefore be expressed by an excitation coefficient analogous to Town send’s ionization coefficient. Excitation rates must be known to calculate secondary effects by photo-electric emission from a cathode. A novel method of intensity measurements by counting quanta vacuum ultra-violet radiation has been developed, using a fluorescent converter, photo -multiplier and scaler, to obtain the absolute magnitude of the excitation coefficient as a function of the electric field. The absolute in tensity of the radiation was found by means of a photo-chemical reaction of known quantum efficiency. With electron currents up to 10 -8 A it was shown that the emitted flux of ultra-violet quanta was proportional to the current and varied exponentially with distance from the cathode, in agreement with theory. The rate of dissociation of molecular hydrogen in an electrodeless discharge was measured by absorbing the atomic hydrogen formed and observing the rate of decrease of gas pressure. From this and electric data a dissociation coefficient was calculated showing that dissociation losses account for a large part of the energy balance. It seems that dissociation proceeds principally by electronic excitation from the ground state 1 1 ∑ g to the lowest repulsive state 1 3 ∑ u . An average cross-section of 0.2 ╥a 2 0 has been obtained for this transition in moderate electric fields.

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Space Charge Effects Due to Near Contact Non-Uniform Electric Fields in Semi-Insulating GaAs

MRS Proceedings ◽

10.1557/proc-261-101 ◽

1992 ◽

Vol 261 ◽

Author(s):

Narbeh Derhacobian ◽

Nancy M. Haegel

Keyword(s):

Theoretical Model ◽

Electric Field ◽

Electric Fields ◽

Power Law ◽

Current Density ◽

Charge Effects ◽

Constant Bias ◽

Contact Field ◽

Minority Carriers ◽

Good Agreement

ABSTRACTVariable length semi-insulating GaAs p+-υ-n+ diodes are used to investigate the influence of near contact electric field non-uniformities on the injection of minority carriers. The results show that despite the presence of highly linear IV characteristics, significant nonuniformities in the electric field dominate the device response. The current density through the device is shown to depend on the device length with a power law J ∞ (L)1.0 at a constant bias. The experimental results are compared, with good agreement, to a theoretical model which treats semi-insulating GaAs as a trap-dominated relaxation semiconductor. Electroabsorption measurements are used to observe the slow transients associated with the appearance of near contact field nonuniformities.

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Tuning the Electric Field Response of MOFs by Rotatable Dipolar Linkers

10.26434/chemrxiv.8153198.v1 ◽

2019 ◽

Author(s):

Johannes P. Dürholt ◽

Babak Farhadi Jahromi ◽

Rochus Schmid

Keyword(s):

Electric Field ◽

Electric Fields ◽

Structural Changes ◽

Dielectric Behavior ◽

Two Dimensions ◽

Dielectric Constants ◽

Electric Response ◽

Dipole Strength ◽

Metal Organic ◽

Dynamics Simulations

Recently the possibility of using electric fields as a further stimulus to trigger structural changes in metal-organic frameworks (MOFs) has been investigated. In general, rotatable groups or other types of mechanical motion can be driven by electric fields. In this study we demonstrate how the electric response of MOFs can be tuned by adding rotatable dipolar linkers, generating a material that exhibits paralectric behavior in two dimensions and dielectric behavior in one dimension. The suitability of four different methods to compute the relative permittivity κ by means of molecular dynamics simulations was validated. The dependency of the permittivity on temperature T and dipole strength μ was determined. It was found that the herein investigated systems exhibit a high degree of tunability and substantially larger dielectric constants as expected for MOFs in general. The temperature dependency of κ obeys the Curie-Weiss law. In addition, the influence of dipolar linkers on the electric field induced breathing behavior was investigated. With increasing dipole moment, lower field strength are required to trigger the contraction. These investigations set the stage for an application of such systems as dielectric sensors, order-disorder ferroelectrics or any scenario where movable dipolar fragments respond to external electric fields.

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Meta-Deflectors Made of Dielectric Nanohole Arrays with Anti-Damage Potential

Photonics ◽

10.3390/photonics8040107 ◽

2021 ◽

Vol 8 (4) ◽

pp. 107

Author(s):

Haichao Yu ◽

Feng Tang ◽

Jingjun Wu ◽

Zao Yi ◽

Xin Ye ◽

...

Keyword(s):

Electric Field ◽

Electric Fields ◽

Laser Cutting ◽

High Complexity ◽

Damage Potential ◽

Optical Components ◽

Nanohole Arrays ◽

Intense Light ◽

Polarization Of Light ◽

Air Hole

In intense-light systems, the traditional discrete optical components lead to high complexity and high cost. Metasurfaces, which have received increasing attention due to the ability to locally manipulate the amplitude, phase, and polarization of light, are promising for addressing this issue. In the study, a metasurface-based reflective deflector is investigated which is composed of silicon nanohole arrays that confine the strongest electric field in the air zone. Subsequently, the in-air electric field does not interact with the silicon material directly, attenuating the optothermal effect that causes laser damage. The highest reflectance of nanoholes can be above 99% while the strongest electric fields are tuned into the air zone. One presentative deflector is designed based on these nanoholes with in-air-hole field confinement and anti-damage potential. The 1st order of the meta-deflector has the highest reflectance of 55.74%, and the reflectance sum of all the orders of the meta-deflector is 92.38%. The optothermal simulations show that the meta-deflector can theoretically handle a maximum laser density of 0.24 W/µm2. The study provides an approach to improving the anti-damage property of the reflective phase-control metasurfaces for intense-light systems, which can be exploited in many applications, such as laser scalpels, laser cutting devices, etc.

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Integrating flexible electronics for pulsed electric field delivery in a vascularized 3D glioblastoma model

npj Flexible Electronics ◽

10.1038/s41528-021-00115-x ◽

2021 ◽

Vol 5 (1) ◽

Author(s):

Marie C. Lefevre ◽

Gerwin Dijk ◽

Attila Kaszas ◽

Martin Baca ◽

David Moreau ◽

...

Keyword(s):

Electric Field ◽

Electric Fields ◽

Flexible Electronics ◽

Soft Tissues ◽

Multiphoton Microscopy ◽

Membrane Integrity ◽

Tumor Model ◽

Pulsed Electric Fields ◽

In Ovo ◽

Cell Membrane Integrity

AbstractGlioblastoma is a highly aggressive brain tumor, very invasive and thus difficult to eradicate with standard oncology therapies. Bioelectric treatments based on pulsed electric fields have proven to be a successful method to treat cancerous tissues. However, they rely on stiff electrodes, which cause acute and chronic injuries, especially in soft tissues like the brain. Here we demonstrate the feasibility of delivering pulsed electric fields with flexible electronics using an in ovo vascularized tumor model. We show with fluorescence widefield and multiphoton microscopy that pulsed electric fields induce vasoconstriction of blood vessels and evoke calcium signals in vascularized glioblastoma spheroids stably expressing a genetically encoded fluorescence reporter. Simulations of the electric field delivery are compared with the measured influence of electric field effects on cell membrane integrity in exposed tumor cells. Our results confirm the feasibility of flexible electronics as a means of delivering intense pulsed electric fields to tumors in an intravital 3D vascularized model of human glioblastoma.

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Electro-Optic Control of Lithium Niobate Bulk Whispering Gallery Resonators: Analysis of the Distribution of Externally Applied Electric Fields

Crystals ◽

10.3390/cryst11030298 ◽

2021 ◽

Vol 11 (3) ◽

pp. 298

Author(s):

Yannick Minet ◽

Hans Zappe ◽

Ingo Breunig ◽

Karsten Buse

Keyword(s):

Lithium Niobate ◽

Electric Field ◽

Electric Fields ◽

Frequency Comb ◽

Parametric Oscillation ◽

Pockels Effect ◽

Optical Mode ◽

Cylindrical Resonator ◽

Whispering Gallery ◽

Electro Optic

Whispering gallery resonators made out of lithium niobate allow for optical parametric oscillation and frequency comb generation employing the outstanding second-order nonlinear-optical properties of this material. An important knob to tune and control these processes is, e.g., the linear electro-optic effect, the Pockels effect via externally applied electric fields. Due to the shape of the resonators a precise prediction of the electric field strength that affects the optical mode is non-trivial. Here, we study the average strength of the electric field in z-direction in the region of the optical mode for different configurations and geometries of lithium niobate whispering gallery resonators with the help of the finite element method. We find that in some configurations almost 100% is present in the cavity compared to the ideal case of a cylindrical resonator. Even in the case of a few-mode resonator with a very thin rim we find a strength of 90%. Our results give useful design considerations for future arrangements that may benefit from the strong electro-optic effect in bulk whispering gallery resonators made out of lithium niobate.

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Double layers in the downward current region of the aurora

Nonlinear Processes in Geophysics ◽

10.5194/npg-10-45-2003 ◽

2003 ◽

Vol 10 (1/2) ◽

pp. 45-52 ◽

Cited By ~ 32

Author(s):

R. E. Ergun ◽

L. Andersson ◽

C. W. Carlson ◽

D. L. Newman ◽

M. V. Goldman

Keyword(s):

Magnetic Field ◽

Electron Beam ◽

Phase Space ◽

Electric Field ◽

Electric Fields ◽

Double Layers ◽

Parallel Electric Field ◽

Electrostatic Waves ◽

Current Region ◽

Decisive Evidence

Abstract. Direct observations of magnetic-field-aligned (parallel) electric fields in the downward current region of the aurora provide decisive evidence of naturally occurring double layers. We report measurements of parallel electric fields, electron fluxes and ion fluxes related to double layers that are responsible for particle acceleration. The observations suggest that parallel electric fields organize into a structure of three distinct, narrowly-confined regions along the magnetic field (B). In the "ramp" region, the measured parallel electric field forms a nearly-monotonic potential ramp that is localized to ~ 10 Debye lengths along B. The ramp is moving parallel to B at the ion acoustic speed (vs) and in the same direction as the accelerated electrons. On the high-potential side of the ramp, in the "beam" region, an unstable electron beam is seen for roughly another 10 Debye lengths along B. The electron beam is rapidly stabilized by intense electrostatic waves and nonlinear structures interpreted as electron phase-space holes. The "wave" region is physically separated from the ramp by the beam region. Numerical simulations reproduce a similar ramp structure, beam region, electrostatic turbulence region and plasma characteristics as seen in the observations. These results suggest that large double layers can account for the parallel electric field in the downward current region and that intense electrostatic turbulence rapidly stabilizes the accelerated electron distributions. These results also demonstrate that parallel electric fields are directly associated with the generation of large-amplitude electron phase-space holes and plasma waves.

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Clarifications on the Behavior of Alternative Gases to SF6 in Divergent Electric Field Distributions under AC Voltage

Energies ◽

10.3390/en14041065 ◽

2021 ◽

Vol 14 (4) ◽

pp. 1065

Author(s):

Houssem Eddine Nechmi ◽

Michail Michelarakis ◽

Abderrahmane (Manu) Haddad ◽

Gordon Wilson

Keyword(s):

Electric Field ◽

Electric Fields ◽

Partial Discharge ◽

Mean Value ◽

Electrode System ◽

Polarity Reversal ◽

Buffer Gas ◽

Co2 Gas ◽

Breakdown Mechanism ◽

Positive Cycle

Negative and positive partial discharge inception voltages and breakdown measurements are reported in a needle-plane electrode system as a function of pressure under AC voltage for natural gases (N2, CO2, and O2/CO2), pure NovecTM gases (C4F7N and C5F10O) and NovecTM in different natural gas admixtures. For compressed 4% C4F7N–96% CO2 and 6% C5F10O–12% O2–82% CO2 gas mixtures, the positive-streamer mode is identified as the breakdown mechanism. Breakdown and negative partial discharge inception voltages of 6% C5F10O–12% O2–82% CO2 are higher than those of 4% C4F7N–96% CO2. At 8.8 bar abs, the breakdown voltage of 6% C5F10O–12% O2–82% CO2 is equal to that of 12.77% O2–87.23% CO2 (buffer gas). Synergism in negative partial discharge inception voltage/electric field fits with the mean value and the sum of each partial pressure individually component for a 20% C4F7N–80% CO2 and 6% C5F10O–12% O2–82% CO2, respectively. In 9% C4F7N–91% CO2, the comparison of partial discharge inception electric fields is Emax (CO2) = Emax(C4F7N), and Emax (12.77% O2–87.23% CO2) = Emax(C5F10O) in 19% C5F10O–81%(12.77% O2–87.23% CO2). Polarity reversal occurs under AC voltage when the breakdown polarity changes from negative to positive cycle. Polarity reversal electric field EPR was quantified. Fitting results show that EPR (CO2) = EPR(9% C4F7N–91% CO2) and EPR(SF6) = EPR (22% C4F7N–78% CO2). EPR (4% C4F7N–96% CO2) = EPR (12.77% O2–87.23% CO2) and EPR (6% C5F10O–12% O2–82% CO2) < EPR (4% C4F7N–96% CO2) < EPR (CO2).

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