scholarly journals Ionization Waves Enhance the Production of X-rays during Streamer Collisions

Atmosphere ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1101
Author(s):  
Vernon Cooray ◽  
Gerald Cooray ◽  
Marcos Rubinstein ◽  
Farhad Rachidi
Keyword(s):  
Experimental Data ◽  
Electric Field ◽  
Electric Fields ◽  
Time Synchronization ◽  
Field Enhancement ◽  
Opposite Polarity ◽  
X Rays ◽  
Weakly Conducting ◽  
Ionization Waves ◽  
Discharge Gap

Experimental data show that in laboratory sparks, X-rays are produced in time synchronization with the meeting of streamers of opposite polarity just before the final breakdown of the discharge gap. It has been suggested that the electric field enhancement created during the collision of streamers could provide the necessary conditions for electron acceleration, even though some of the theoretical studies show that the duration of the electric field is not long enough to do so. The experimental data on laboratory discharges show that. when streamers of opposite polarity meet each other, a potential or ionization wave that renders the streamer channels conducting is initiated. This paper shows that these ionization waves that convert the discharge channels from weakly conducting to highly conducting are associated with electric fields large enough to accelerate electrons to relativistic energies.

scholarly journals Using Wavelet Transform To Extract Frequency Content In Electric Field Radiated By Unusual Lightning Activity

2021 ◽  
Vol 14 (14) ◽  
pp. 62-67
Author(s):  
Suraj Neupane ◽  
Shriram Sharma ◽  
Puja Sharma
Keyword(s):  
Wavelet Transform ◽  
Electric Field ◽  
Electric Fields ◽  
Time Domain ◽  
Opposite Polarity ◽  
Frequency Content ◽  
Field Change ◽  
Polarity Field ◽  
Main Activity ◽  
Domain Information

In this frequency spectrum electric fields radiated by the unusual lightning activities have been computed using the wavelet transform technique. The unusual lightning activities have very recently been identified activities and are very poorly understood among the lightning community. As the electric fields are very recently identified and are measured in time domain, to the best of our knowledge, their frequency content has not been studied as of today. To understand the physics of the discharge mechanism of such events, the frequency domain information plays a significant role. In order to extract frequency domain information from the time domain electric field signatures the wavelet transform technique has been employed. For the purpose, the electric field pertinent to the unusual activity, has been divided into two parts namely main activity and the preceding opposite polarity field change.  From the computation, it is found that the opposite-polarity field change radiates energy in the spectral range of 2 kHz to 173 kHz whereas, the main activity predominantly radiates in the frequency range 2 kHz to 162 kHz. Such a wider spectral range that the unusual activities radiate have not been reported for the other known activities such as positive and negative return strokes. Evidently, the unusual events have some unique origin of discharge unlike the known activities. Further, as the unusual events were noticed in the temperate region (Uppsala, Sweden) and Sub-tropical climatic zone (Kathmandu, Nepal), it should have some common source of origin between two regions.

Ion-Beam-Synthesised Ag-SiO2 Nanocomposite Layers for Electron Field Emission Devices

2005 ◽  
Vol 908 ◽  
Author(s):  
Wei-Mong Tsang ◽  
V. Stolojan ◽  
A. A. D. T. Adikaari ◽  
S. P. Wong ◽  
S. R. P. Silva
Keyword(s):  
Electric Field ◽  
Field Emission ◽  
Electric Fields ◽  
Integrated Circuit ◽  
Ion Beam ◽  
Field Enhancement ◽  
Pure Metal ◽  
Local Electric Field ◽  
Electric Field Enhancement ◽  
Local Electric Field Enhancement

AbstractAg-SiO2 nanocomposite layers were synthesised by Ag+ implantation into thermally oxidised SiO2 layers and demonstrated to have excellent field emission (FE) properties. These nanocomposite layers can give an emission current of 1 nA at electric fields less than 20 V/μm, compared to several thousand volts per micrometre of pure metal surfaces. Their fabrication processes are fully compatible with existing integrated circuit technology. By correlating the FE results with other characterisation techniques including atomic force microscopy, Rutherford backscattering spectroscopy and transmission electron microscopy, it is clearly demonstrated that there are two types of field enhancement mechanisms responsible for the excellent FE properties of these cathodes. Firstly, the electrically conductive Ag nano-clusters embedded in the insulating SiO2 matrix give rise to a local electric field enhancement due to an electrical inhomogeneity effect and secondly, the dense surface protrusions provide a geometric local electric field enhancement. The FE properties of these layers are critically dependent on the size and distribution of the Ag clusters, which can be controlled by the Ag dose and modified by the post-implantation pulse annealing with a high power KrF Excimer laser operating at 248 nm.

Modeling of Nanoparticle-Mediated Electric Field Enhancement Inside Biological Cells Exposed to AC Electric Fields

2009 ◽  
Vol 48 (8) ◽  
pp. 087001 ◽  
Author(s):  
Pawan K. Tiwari ◽  
Sung Kil Kang ◽  
Gon Jun Kim ◽  
Jun Choi ◽  
A.-A. H. Mohamed ◽  
...  
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Field Enhancement ◽  
Biological Cells ◽  
Electric Field Enhancement ◽  
Ac Electric Fields

Synergistic electric field enhancement of the effectiveness of chlorine species formed during electrochemical disinfection of drinking water

2012 ◽  
Vol 12 (6) ◽  
pp. 862-868
Author(s):  
Hilary Nath ◽  
Alan Langdon
Keyword(s):  
Drinking Water ◽  
Electric Field ◽  
Electric Fields ◽  
Field Enhancement ◽  
Electrode Gap ◽  
Electrochemical Disinfection ◽  
Reversible Electroporation ◽  
Flow Through ◽  
Escherichia Coli Bacteria

In line in situ electrochemical disinfection of drinking water with chloride concentrations as low as 10 mg/L has been demonstrated at practical flow rates of at least 3 m3/day using a novel perforated electrode flow through (PEFT) cell with a 50 μm inter-electrode gap. Sufficient chlorine to achieve 6 log inactivation of Escherichia coli bacteria was produced at applied voltages as low as 5 V and with energy consumptions as low as 0.5 kWh/m3. At slightly higher applied voltages, the specific lethality of electrochemically produced chlorine was enhanced by at least two orders of magnitude to greater than 50 L/mg min. This dramatically enhanced lethality is consistent with a synergistic effect resulting from reversible electroporation when electric fields greater than 1.3 kV/cm are produced. There was no evidence for involvement of other species such as reactive oxygen species (ROSs). Disinfection of drinking water using the PEFT cell is cost competitive with other disinfection technologies and when enhanced by the electric field is much less likely to produce disinfection by products.

Electrohydrodynamics of Drops and Vesicles

2019 ◽  
Vol 51 (1) ◽  
pp. 305-330 ◽  
Author(s):  
Petia M. Vlahovska
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Lipid Membranes ◽  
Uniform Electric Field ◽  
Dielectric Fluids ◽  
Weakly Conducting ◽  
Strong Electric Fields ◽  
Leaky Dielectric ◽  
Quincke Rotation ◽  
Experimental And Theoretical Studies

The 1969 review by J.R. Melcher and G.I. Taylor defined the field of electrohydrodynamics. Fifty years on, the interaction of weakly conducting (leaky dielectric) fluids with electric fields continues to yield intriguing phenomena. The prototypical system of a drop in a uniform electric field has revealed remarkable dynamics in strong electric fields such as symmetry-breaking instabilities (e.g., Quincke rotation) and streaming from the drop equator. This review summarizes recent experimental and theoretical studies in the area of fluid particles (drop and vesicles) in electric fields, with a focus on the transient dynamics and extreme deformations. A theoretical framework to treat the time evolution of nearly spherical shapes is provided. The model has been successful in describing the dynamics of vesicles (closed lipid membranes) in an electric field, highlighting the broader range of applicability of the leaky dielectric approach.

TERAHERTZ RADIATION IN SUPERLATTICES IN MODERATE ELECTRIC FIELD

2006 ◽  
Vol 20 (08) ◽  
pp. 937-945 ◽  
Author(s):  
PENG HAN ◽  
KUI-JUAN JIN ◽  
YUE-LIANG ZHOU ◽  
QING-LI ZHOU ◽  
K. HIRAKAWA
Keyword(s):  
Experimental Data ◽  
Electric Field ◽  
Electric Fields ◽  
Radiation Intensity ◽  
Wave Functions ◽  
Thz Radiation ◽  
Field Region ◽  
Three Samples ◽  
Moderate Electric Field ◽  
Theoretical Results

We have studied the terahertz (THz) radiation in superlattices (SLs) in moderate electric field region (between 12 kV/cm and 25 kV/cm) from both theoretical and experimental aspects in this work. The THz emission intensity has been calculated for three samples of GaAs/Al 0.3 Ga 0.7 As SLs by using Kane model. The theoretical results show that the radiation intensity increases until the electric field F achieves a certain value between 14 kV/cm and 16 kV/cm for various samples, and then starts to roll off. The agreement of the calculated results with the experimental data demonstrates that the rolling of THz radiation intensity is due to the competition of field induced localization of wave functions and the increasing of the photon energy in THz radiation with increased electric fields. Furthermore, it is also shown that THz radiation intensity can be affected by the scattering of the randomly distributed Al atoms in the barriers.

scholarly journals Optical Anapole Modes in Gallium Phosphide Nanodisk with Forked Slits for Electric Field Enhancement

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1490
Author(s):  
Jingwei Lv ◽  
He Zhang ◽  
Chao Liu ◽  
Zao Yi ◽  
Famei Wang ◽  
...  
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Hot Spots ◽  
Gallium Phosphide ◽  
Physical Phenomenon ◽  
Near Field ◽  
Field Enhancement ◽  
High Refractive Index ◽  
Novel Approach ◽  
New Frontier

High refractive index dielectric nanostructures represent a new frontier in nanophotonics, and the unique semiconductor characteristics of dielectric systems make it possible to enhance electric fields by exploiting this fundamental physical phenomenon. In this work, the scattered radiation spectral features and field-enhanced interactions of gallium phosphide disks with forked slits at anapole modes are investigated systematically by numerical and multipole decomposition analyses. Additional enhancement of the electric field is achieved by opening the forked slits to create high-intensity hot spots inside the disk, and nearby molecules can access these hot spots directly. The results reveal a novel approach for near-field engineering such as electric field localization, nonlinear optics, and optical detection.

scholarly journals Model Based Design and Validation of a Batch Ohmic Heating System

Modelling ◽  
2021 ◽  
Vol 2 (4) ◽  
pp. 641-658
Author(s):  
Oluwaloba Oluwole-ojo ◽  
Hongwei Zhang ◽  
Martin Howarth ◽  
Xu Xu
Keyword(s):  
Experimental Data ◽  
System Identification ◽  
Electric Field ◽  
Electric Fields ◽  
Model Comparison ◽  
Initial Conditions ◽  
Numerical Models ◽  
Ohmic Heating ◽  
Model Development ◽  
Food Products

Using moderate electric field (MEF) techniques, Ohmic heating (OH) provides the rapid and uniform heating of food products by applying electric fields to them. A range of theoretical Ohmic heating models have been studied by researchers, but model validation and comparisons using experimental data and model development using system identification techniques from experimental data have not been evaluated. In this work, numerical models, mathematical models, and system identification models for an MEF process were developed. The MEF models were developed and simulated using COMSOL and MATLAB/Simulink software. When simulated, the developed models showed a volumetric rise in the overall food temperature. It was found that upon the application of an electric field, the resultant temperature depends on the electrical conductivity, product temperature, and magnitude of the electric field. For this reason, a systematic approach was used to validate the developed models. Experimental data derived from a commercially available batch Ohmic heater from C-Tech Innovation were used to validate the simulated models. Validation, analysis, and model comparison were conducted to compare developed models with experimental data. The validated simulated model helped improve the understanding of the effect of different critical process parameters of foods with a range of initial conditions. The validated model could accurately predict the temperature of heating under varying electric fields and food products with different thermo–physical properties.

Electric Field Enhancement of Dark Current Generation in Detectors

2004 ◽  
Vol 829 ◽  
Author(s):  
James P. Lavine
Keyword(s):  
Activation Energy ◽  
Electric Field ◽  
Electric Fields ◽  
Dark Current ◽  
Field Enhancement ◽  
Electric Field Enhancement ◽  
Current Generation ◽  
Field Relation ◽  
Defects And Impurities ◽  
A Charge

ABSTRACTThe performance of detectors and sensors is degraded by dark current generation, which is due to defects and impurities in the materials. Electric fields enhance the generation from the resulting deep levels. When the electric field is in the mid-105 V/cm range, the present work finds enhancements of the order of 100 or more for iron and gold in silicon. The activation energy of the generation rate as a function of temperature is seen to decrease when the electric field increases. Many detectors have pixels that form a charge packet before the detectors are read out. Since the presence of charge decreases the electric field, the electric field enhancement varies with time. This is modeled for iron in silicon with an illustrative charge versus electric field relation. The resulting activation energy is found to be barely affected.

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