Electric Radius Research Articles

Precise determination of the proton magnetic radius from electron scattering data

We extract the proton magnetic radius from the high-precision electron-proton elastic scattering cross section data. Our theoretical framework combines dispersion analysis and chiral effective field theory and implements the dynamics governing the shape of the low-$Q^2$ form factors. It allows us to use data up to $Q^2\sim$ 0.5 GeV$^2$ for constraining the radii and overcomes the difficulties of empirical fits and $Q^2 \rightarrow 0$ extrapolation. We obtain a magnetic radius $r_M^p$ = 0.850 $\pm$0.001 (fit 68%) $\pm$0.010 (theory full range) fm, significantly different from earlier results obtained from the same data, and close to the extracted electric radius $r_E^p$ = 0.842 $\pm$0.002 (fit) $\pm$0.010 (theory) fm.

Reanalysis of low-energy electron-proton scattering data and proton radius

We reanalyze electron-proton scattering data in the momentum transfer region Q2<1GeV2, which were used to determine proton electric radius, with main focus on the Mainz experiment (Bernauer et al. 2010). We examine dependence of fit results and χ2 on the cut-off in Q2 and degree of fitting polynomial, using pseudo-data and compare it with the case of real experimental data. We find that under some assumptions, the data could be consistent with the radius, obtained from muonic hydrogen.

A Six-Component Vector Sensor Comprising ElectricallyLongDipoles andLargeLoops— To Simultaneously Estimate Incident Sources’ Directions-of-Arrival and Polarizations

An “electromagnetic vector sensor” (EMVS) comprises three orthogonal dipoles and three orthogonal loops, all in spatial collocation. The former triplet aims to directly measure the 3 × 1 electric-field vector e, whereas the latter triplet aims to directly measure the 3 × 1 magnetic-field vector h. Their vector cross product e × h would yield the incident source's Poynting vector, which specifies the incident wavefield's propagation direction. In reality, all these are only an idealization. Instead, a real-world dipole triad's measurement could equal the incident e, only if the dipoles were electrically short (i.e., with an electrical length of (L/λ) <; 0.1). Likewise, a practical loop triad's measurement could equal the incident h, only if the loops were electrically small (i.e., with an electrical circumference of 2π(R/λ) <; 0.1). However, such short dipoles and small loops would be electromagnetically inefficient receivers. For a practical dipole that is electrically long, its measurement equals not the incident wavefield's e but a vector dot product between: 1) the incident wave's e and 2) that dipole antenna's “effective length” vector (which depends on that dipole's (L/λ) and orientation). An analogous complexity exists for a practical loop that is electrically large. For such practical dipoles and loops, the aforementioned vector-cross-product would fail to yield the Poynting vector, hence it would inaccurately estimate the direction-of-arrival. Instead, this article will advance a new closed-form algorithm to simultaneously estimate an incident source's direction-ofarrival and polarization, despite the practical dipoles'/ loops' mathematically complicated gain/phase responses as described earlier, but without any prior knowledge of the dipoles' electric length (L/λ) nor the loops' electric radius (R/λ).

Dynamic calculation and thermal enhancement mechanism analysis of nanofluid under electric field

Abstract The dynamic model of nanoparticle in the basefluid under the electric field is proposed to simulate the motion and track zone characteristics of nanoparticle in the basefluid under the electric field. The effects of electric field, temperature, zeta potential and radius of nanoparticle are discussed in the present study. Besides, the heat transfer enhancement mechanism of nanofluid under the electric field is analyzed. The results show that: the magnitude velocity of nanoparticle in the basefluid is enhanced little by the electric field. While, the track zone range of nanoparticle is enhanced greatly. Specifically, the track zone of nanoparticle under the electric field is increased by increasing the electric field intensity, temperature and zeta potential. However, that is decreased by increasing the radius of nanoparticle. By changing the direction of the electric field in a certain time, the track zone of nanoparticle can be controlled to limit in a certain range. The energy transport and thermal conductivity enhancement mechanism of nanofluid under the electric field is also analyzed in the present study.

Calculation of thin wire conductivity in a longitudinal magnetic field taking into account Fuchs boundary conditions

The task about thin wire conductivity in a longitudinal stationary magnetic field and alternative electrical field is solved by the kinetic method in the view of Fuchs model. The ratio between the wire radius and the charge carrier mean free path is arbitrary. Electric and magnetic fields are homogeneous. The wire radius is much less than the skin layer depth, i.e. the skin effect is neglected. The limiting cases of a degenerate and nondegenerate electron gas are considered. The conductivity dependences on the magnetic field induction, electric field frequency, wire radius and surface specularity coefficient are investigated. Results obtained for limiting cases of degenerate and nondegenerate electron gas are compared. Also, these results are compared with experimental data. An effective method for determining the surface specularity coefficient and charge carrier mean free path is illustrated. The dependence of the charge carrier mean free path in a sample volume on the wire radius is analyzed.

Зависимость процессов в дугогасительной решетке от радиуса движущейся электрической дуги

In electrical apparatuses containing an arc chute, arc occurs initially on the contacts arranged between the insulating walls spaced at a relatively wide distance from each other, after which the electromagnetic forces drive the arc into the area occupied by the chute plates. Electric arc is a complex phenomenon, in which a large number of physical interactions occur within a very short period of time. An analysis and calculation of arc processes in the arc quenching devices of electrical apparatuses imply simultaneous consideration of thermal gas dynamic, kinetic, electrical (network), arc, and mechanical processes. This adds much difficulty to a search of acceptable models that would satisfy all these requirements. The difficulties of solving the equations that are based on the general principles of thermodynamics and the laws of continuum mechanics are connected, in particular, with the validity of boundary and initial conditions, which are usually selected with due regard for experimental data (it should be noted that the experimental techniques in studying an arc are quite sophisticated and costly). In the course of many years, many electric arc modeling methods have been developed. The following three basic types of electric arc models should be pointed out: a physical model, a black box model, and a parametric model. These models cannot show all physical processes in an electric arc, but they can describe the variations of the main parameters. The physical processes accompanying the arc motion can slow down or even stop its displacement, which may lead to an emergency. Therefore, it is very important to select the arch chute parameters in such a way that it would offer the lowest resistance to the arc motion. In this regard, it is of primary importance to estimate the electric arc channel radius. The article is devoted to calculating the electric arc channel radius. The calculations presented in the article can be useful in selecting the parameters of arc chute plates.

PSO-based Siting and Sizing of Electric Vehicle Charging Stations

With the rapid growth of the number of electric vehicles, the optimization of charging network is imminent. In this paper, a screening method for the siting and sizing of electric vehicle charging station is developed to minimize the total cost including capital investment on stations, EV charging stations’ operation cost and maintenance cost. Driving distance of electric vehicles and service radius of stations are taken into account to pick out the optimal sites of EV charging stations. A mathematical model with electric physical constraints is designed to distribute appropriate capacities for each EV charging station to prevent the negative effects on the power grid and the PSO optimization algorithm is applied to obtain the optimal sizing parameters. Finally, the IEEE 123-bus test feeder case study is used to confirm the validity of the proposed method and increase the economic benefits.

Plasma-Dielectric Traveling Wave Antenna

The paper investigates the efficiency of transformation of traveling wave into radiation in longitudinally inhomogeneous plasma cylinder. The plasma is limited by a dielectric shell of finite thickness. The investigation involves the use of the method of spectral field expansion in terms of a set of functions including the surface and spatial waves of plasma cylinder with dielectric shell. A system of integro-differential equations for expansion coefficients has been obtained. These coefficients determine the amplitudes of transmitted, reflected, and scattered waves and also radiation patterns (RP). The system of equations is solved for the case of strong longitudinal variation of plasma density. The relationships of the transformation coefficients of surface wave energy as a function of the plasma density gradient, electrical length of section of plasma inhomogeneity, the electric radius of plasma cylinder, dielectric permittivity, and the thickness of dielectric were calculated. The fraction of surface wave energy that is transformed into radiation at acute angles can amount to 35%. The resultant narrow-beam RPs have only one lobe. The radiation maximum fits into an angle of several degrees with respect to the direction of surface wave propagation. With an increase of plasma density gradient, the lobe width is reduced, while its position shifts to 0°. The impact of dielectric properties on radiation characteristics has been also investigated.

Analytical description of the size effect on pyroelectric and electrocaloric properties of ferroelectric nanoparticles

Using Landau-Ginzburg-Devonshire theory and effective medium approximation, we analytically calculate typical dependences of the pyroelectric and electrocaloric coefficients on external electric field, temperature and radius for spherical single-domain ferroelectric nanoparticles. The considered physical model corresponds to the nanocomposite with small fraction of ferroelectric nanoparticles. Within the framework of the analytical model we establish how the size changes determine the temperature and field behavior pyroelectric and electrocaloric coefficients on example of BaTiO3 nanoparticles covered by a semiconducting shell and placed in a dielectric polymer. We show that by changing the particle size one can induce maxima of the pyroelectric coefficient and electrocaloric temperature variation, control their width, height and sign. Obtained analytical expressions allow selecting the interval of particle sizes, voltage, and/or temperature for which pyroelectric energy conversion and electrocaloric coefficient are optimal for applications. The observed size effect opens the possibility to control pyroelectric and electrocaloric properties of ferroelectric nanocomposites that can be important for their advanced applications in energy convertors and cooling systems.

AC dielectrophoretic deformable particle-particle interactions and their relative motions.

This paper develops a numerical simulation model to research the deformable particle-particle interactions caused by dielectrophoresis (DEP) under AC electric fields. The DEP force is calculated by using Maxwell stress tensor method, and the hydrodynamic force is obtained by calculating the hydrodynamic stress tensor. Simulation results show that the DEP interactive motion will facilitate the particles forming particle chains that are parallel to the electric field, and the particles with low shear modulus present a lower x-component velocity. Also, the electric field intensity and particles radius have some effects on the DEP motions, and for different particles, smaller particles with larger electric field intensity easily reach a larger velocity. The numerical research may provide universal guidance for biological cells manipulation and assembly.

Proton and neutron electromagnetic form factors from lattice QCD

The electromagnetic form factors of the proton and the neutron are computed within lattice QCD using simulations with quarks masses fixed to their physical values. Both connected and disconnected contributions are computed. We analyze two new ensembles of $N_f = 2$ and $N_f = 2 + 1 + 1$ twisted mass clover-improved fermions and determine the proton and neutron form factors, the electric and magnetic radii, and the magnetic moments. We use several values of the sink-source time separation in the range of 1.0 fm to 1.6 fm to ensure ground state identification. Disconnected contributions are calculated to an unprecedented accuracy at the physical point. Although they constitute a small correction, they are non-negligible and contribute up to 15% for the case of the neutron electric charge radius.

WITHOUT A CONFLICT MODEL OF ELECTRON

The model of electron is offered with quark distribution of charge density and ”white hole” (on similarity of ”black hole” in gravitation) in a center. Such structure abolishes the crisis of electromagnetic mass, calculated on universal formula and on the impulse of the electromagnetic field. A model in order to please a classic electrodynamics keeps monolithic nature of elementary particle, and in order to please a quantum allows the separate charged zones to interpret as separate quarks. Coming from harmony of spheres of the separate charged zones, a white hole can be interpreted as white (neutral) quark conditionally in addition to three coloured. As after the electric radius re = 1.185246·10−15 m of white hole the laws of electricity do not operate, then the crisis of point charge is removed at the same time too, because of must be: r ≥ re.

Effects of buried grain boundaries in multilayer MoS2

Two-dimensional transition metal dichalcogenides have been the focus of intense research for their potential application in novel electronic and optoelectronic devices. However, growth of large area two-dimensional transition metal dichalcogenides invariably leads to the formation of grain boundaries that can significantly degrade electrical transport by forming large electrostatic barriers. It is therefore critical to understand their effect on the electronic properties of two-dimensional semiconductors. Using MoS2 as an example material, we are able to probe grain boundaries in top and buried layers using conductive atomic force microscopy. We find that the electrical radius of the grain boundary extends approximately 2 nm from the core into the pristine material. The presence of grain boundaries affects electrical conductivity not just within its own layer, but also in the surrounding layers. Therefore, electrical grain size is always smaller than the physical size, and decreases with increasing thickness of the MoS2. These results signify that the number of layers in synthetically grown 2D materials must ideally be limited for device applications.

Halo structure of 17C

$^{17}$C has three states below the $^{16}$C + $n$ threshold with quantum numbers $J^P=3/2^+,1/2^+,5/2^+$. These states have relatively small neutron separation energies compared to the neutron separation and excitation energies of $^{16}$C. This separation of scales motivates our investigation of $^{17}$C in a Halo effective field theory (Halo EFT) with a $^{16}$C core and a valence neutron as degrees of freedom. We discuss various properties of the three states such as electric radii, magnetic moments, electromagnetic transition rates and capture cross sections. In particular, we give predictions for the charge radius and the magnetic moment of the $1/2^+$ state and for neutron capture on $^{16}$C into this state. Furthermore, we discuss the predictive power of the Halo EFT approach for the $3/2^+$ and $5/2^+$ states which are described by a neutron in a $D$-wave relative to the core.

Nucleon form factors on a large volume lattice near the physical point in 2+1 flavor QCD

We present results for the isovector nucleon form factors measured on a $96^4$ lattice at almost the physical pion mass with a lattice spacing of 0.085 fm in 2+1 flavor QCD. The configurations are generated with the stout-smeared $O(a)$-improved Wilson quark action and the Iwasaki gauge action at $\beta$=1.82. The pion mass at the simulation point is about 146 MeV. A large spatial volume of $(8.1~{\rm fm})^3$ allows us to investigate the form factors in the small momentum transfer region. We determine the isovector electric radius and magnetic moment from nucleon electric ($G_E$) and magnetic ($G_M$) form factors as well as the axial-vector coupling $g_A$. We also report on the results of the axial-vector ($F_A$), induced pseudoscalar ($F_P$) and pseudoscalar ($G_P$) form factors in order to verify the axial Ward-Takahashi identity in terms of the nucleon matrix elements, which may be called the generalized Goldberger-Treiman relation.

Measurement of the matched spot size in a capillary discharge waveguide with a collimated laser

Measurement of the matched spot size in the hydrogen-filled capillary discharge waveguide based on the spot size oscillation of a collimated laser is presented in this paper. The spot size oscillation trace is retrieved from the laser modes measured at the exits of discharged capillaries of different lengths under the same discharge conditions. With the gas pressure, peak discharge electric current and capillary radius fixed, the radial density profiles are identical in all the discharged capillaries. The measured laser modes are equivalent to the evolution at discrete positions in a long plasma channel. Compared to former researches based on the spot size at the capillary exit, this method is not affected by the multiple solution problem. The use of a collimated laser eliminates the influences of the divergence angle on the fitting accuracy. By this means, the matched spot sizes of hydrogen-filled capillary discharge waveguides under different gas pressures (5-20mbar) are measured. The results can provide a spot size reference for the laser wakefield accelerator guided in a plasma channel.

Energy loss rate of hot electrons due to polar-optical phonon modes in a semiconductor nanowire under transverse electric field

Within the frame of electron-temperature model we calculate the average energy loss rate due to interface and confined longitudinal optical (LO) phonon emission from a hot-electron gas to a cold lattice in polar semiconductor nanowire surrounded by non-polar material. The system both with and without hot-phonon effect is investigated. The impact of a perpendicular electric field on average energy loss rate is explored. The energy loss rate dependences on electric field strength, wire radius and electron temperature are obtained. It has been shown that the energy loss rate is more sensitive to the electric field when the wire radius is larger. The presented results indicate that the electric field applied perpendicularly to the wire axis can serve as a means to control the energy loss rate. There is an experimental evidence concerning to the increase of energy loss rate with increasing electron temperature as we have obtained.

Contact dynamics of nanodroplets in carbon nanotubes: effects of electric field, tube radius, and salt ions

We report contact dynamics of nanodroplets in carbon nanotubes using molecular dynamics simulations. The effects of electric field, nanotube radius, and salt ions included in the nanodroplets are explored in more detail. For the cases without applied electric field, the droplet fills the cross section of carbon nanotubes with small radius completely. When the tube radius becomes larger, the droplet retracts towards the surface of the nanotube to minimize the surface tension of the droplet and shows wider extension along the axial direction. When an electric field perpendicular to the axial direction of the carbon nanotubes is applied, the position and shape of the droplets are changed which is also related to the tube radius and whether the droplet contains salt ions. Unlike a planar surface, the nanotube limits spreading of the droplets along the radial direction. The variation of the center of mass of the droplets indicates a significant confinement to the position of the droplets in the electric field. For the salty water droplets, a strong electric field induces ejection of small water clusters from the droplet in a nanotube with large radius. As a consequence, the droplet and water clusters are separated and moved to two opposite sides of the nanotube by the electric field.

Comparative Features of Electromagnetic Scattering by an Invisible Spherically Symmetric Lens with a Negative Refractive Index

A spherically symmetric lens with a negative refractive index, which can be invisible from the point of view of geometrical optics, is considered. Expressions describing the profile of the refractive index and ray trajectories in the lens, as well as some results of numerical modeling of plane wave scattering by the lens in the rigorous statement of the problem, are presented. It is detected that, unlike in the case of an invisible lens with a positive refractive index, the minima of the radar cross section in the forward direction corresponding to invisibility for the lens with a negative index occur at integer, rather than semi-integer, values of the electric radius, and that their depth is smaller because of the astigmatism associated with focusing of rays on the axis. Some results characterizing influence of losses in the lens on the level of the radar cross-section minima are also presented.

Nucleon form factors in generalized parton distributions at high momentum transfers

This paper aims at calculating the elastic form factors for a nucleon by considering the extended Regge and modified Gaussian ansatzes based on the generalized parton distributions. To reach this goal, we have considered three different parton distribution functions (PDFs) and have compared the obtained results among them for high momentum transfer ranges. Minimum free parameters have been applied in our parametrization. After achieving the form factors, we calculate the electric radius and the transversely unpolarized and polarized densities for the nucleon. Furthermore, we obtain the impact-parameter-dependent PDFs. Finally, we compare our obtained data with the results of previous studies.