Search

It is shown that Lorentz Invariance is a wave phenomenon. The relativistic mass, length contraction and time dilation all follow from the assumption that energy-momentum is constrained to propagate at the speed of light, c, in all contexts, matter as well as radiation. Lorentz Transformations, and both of the usual postulates, then follow upon adopting Einstein clock synchronisation. The wave interpretation proposed here is paradox free and it is compatible with quantum nonlocality., 1 Introduction 'But the division into matter and field is, after the recognition of the equivalence of mass and energy, something artificial and not clearly defined. Could we not reject [...]

Lorentz transmission electron microscopy has been used to study fine-scale exsolution microstructures in ilmenite-hematite, as part of a wider investigation of the lamellar magnetism hypothesis. Pronounced asymmetric contrast is visible in out-of-focus Lorentz images of ilmenite lamellae in hematite. The likelihood that lamellar magnetism may be responsible for this contrast is assessed using simulations that incorporate interfacial magnetic moments on the (001) basal planes of hematite and ilmenite. The simulations suggest qualitatively that the asymmetric contrast is magnetic in origin. However, the magnitude of the experimental contrast is higher than that in the simulations, suggesting that an alternative origin for the observed asymmetry cannot be ruled out. Electron tomography was used to show that the lamellae have lens-like shapes and that (001) planes make up a significant proportion of the interfacial surface that they share with their host. Keywords: Hematite, ilmenite, lamellar magnetism, Lorentz electron microscopy, electron tomography, transmission electron microscopy

How to deal with motion and forces, at the discrete level, is still an open problem, if we want the coupled discrete dynamical system that results from discretization to behave consistently (energy and momentum conservation, etc.). If discretization is conceived as putting together appropriate pieces of a toolkit, this raises the question of which pieces should correspond to items like Lorentz force, Laplace force, Poynting flux, etc. A few such objects (templates for software parts, to some extent) are described, and an approach to the discrete analogue of the Maxwell tensor is outlined. Index Terms--Discrete exterior calculus, forces, Laplace force, Lorentz force, Maxwell tensor.

In this paper, we discuss the development of a 3-D time-domain formulation and simulation code for modeling inductive output tubes (IOTs). This formulation relies on the integration of equivalent circuit equations in time coupled with the Lorentz force equations for particle trajectories. In the case of IOTs and klystrons, the equivalent circuit is a simple inductance-resistance-capacitance model. The same formulation using the equivalent circuit equations for Curnow cavities has been used to simulate coupled-cavity traveling-wave tubes. The connection between the equivalent circuit equations and the forces on the electrons used in the Lorentz force equations is through a scaling of a radio-frequency (RF) field model in which the amplitude is proportional to the cavity voltage. The RF field model can be obtained analytically [as derived in two dimensions by Kosmahl and Branch] or by means of a field map generated by electromagnetic structure simulators. The electron trajectories are integrated in these RF fields as well as using magnetostatic focusing fields and the space-charge fields. The space-charge fields are obtained by mapping the charge to a grid and then solving Poisson's equation. The new code is called NEMESIS, and we discuss the presently implemented IOT model and future development plans. Data on an IOT under development at Communications and Power Industries (CPI; K5H90W-2) have been provided for benchmarking the simulation. Comparison of NEMESIS with both anticipated performance predictions developed using scaling laws developed in-house at CPI and with actual tube performance has been good, and these comparisons are discussed in detail. Index Terms--Inductive output tubes (IOTs), large-signal analysis, nonlinear simulation, time-domain simulation.

I develop a theory of asymptotic inference for the Lorenz curve and the Gini coefficient for testing economic inequality when the data come from stratified and clustered household surveys with large number of clusters per stratum. Using the asymptotic framework of Bhattacharya [Asymptotic Inference from multi-stage surveys. Journal of Econometrics 126(1), 145-171], I derive a weak convergence result for the continuously-indexed Lorenz process even when the underlying density is not uniformly bounded away from zero. I provide analytical formulae for the asymptotic covariance functions that are corrected for both stratification and clustering and develop consistent tests for Lorenz dominance. Inference on the Gini coefficient follows as a corollary. The methods are applied to per capita household expenditure data from the complexly designed Indian national sample survey to test for changes in inequality before and after the reforms of the early 1990s. Ignoring the survey design is seen to produce qualitatively different results, especially in the urban sector where the population sorts more completely into rich and poor neighborhoods. JEL classification: C12; C13; C42 Keywords: Complex survey; Inequality; Lorenz process; Hadamard differentiable; Gini; Dominance

We describe the magnetohydrodynamic (MHD) flow of a viscous, electrically conducting, and incompressible fluid driven by the Lorentz body force inside the annulus between two stationary coaxial cylindrical electrodes under imposed electric and magnetic fields. The azimuthal velocity profile is found for axisymmetrical, fully developed laminar and steady flow at arbitrary annulus curvature and different values of the Hartmann number Ha. It is shown that for Ha[less than or equal to]1, the MHD annular flow behaves as a conventional hydrodynamic fluid driven by an azimuthal Lorentz body force. [DOI: 10.1119/1.2372472]

Abstract: We studied concircular structure spacetimes which are connected 4-dimensional Lorentzian concircular structure manifolds. 2000 Mathematics subject classification: 53C40, 53C50, 53C80 Key words: (CS)[.sub.4]-spacetime, perfect fluid spacetime, scalar curvature, conformally [...]

Since the eddy-current problem usually depends on the geometry of the moving conductive sheet and the pole shape, there is no general method for solving it analytically. This paper presents a method for analysis of the eddy current in the special case of a rotating disk in a time-invariant field. The analysis uses Coulomb's law and the method of images to consider the boundary conditions. First, the surface charge generated in the rotating disk is obtained and Coulomb's law is applied to calculate the electric field intensity, assuming an infinite disk radius. Second, the finite disk radius is taken into account by introducing an imaginary electric field intensity to satisfy the boundary condition that the radial component of the eddy current is zero at the edge of the rotating disk. Third, the braking torque is calculated by applying the Lorentz force law. The paper compares the computed braking torque with the experimental results to establish the validity of the model. Index Terms--Coulomb's law, eddy-current brake (ECB), eddy-current distribution, image method, mapping.

Abstract: In the mathematical model of the special relativity theory, a two-dimensional Minkowski subspace is treated as a one-dimensional direction in the physical space. The manifold of such planes is naturally endowed with the structure of a pseudo-Riemannian manifold on which the group of isochronous Lorentz transformations acts transitively by isometries. In this paper, the topology and the metric geometry of this manifold are studied. Bibliography: 4 titles. Article History: Registration Date: 10/07/2000 Received Date: 11/12/1996 Article note: Translated from Zapiski Nauchnykh Seminar POMI, Vol. 246, 1997, pp. 141--151. Translated by S. Yu. Pilyugin.

A calibration method for multicomponent microforce sensors using Lorentz forces is proposed. The method permits generation of six force and moment components in three orthogonal directions on two-dimensional (2-D) structures that can be fabricated through existing silicon micromachining technology. Two multicomponent microforce sensor and calibration devices were developed and tested to verify the method. Index Terms - Calibration, electromagnetic forces, microforce sensors.

Maxwell's equations are presented in retarded time coordinates, source-free solutions are found which are instantaneously localized. The modified Lorentz force law is discussed.

In order to correlate giant magnetoresistance with changes in magnetic domain structure, we have studied lithographically-defined spin-valve elements in-situ by Lorentz transmission electron microscopy, whilst simultaneously passing a controlled current through the clement and applying a magnetic field. For a given current, the changes in magnetic domain structure can thus be correlated with changes in the resistance of the film. Spin valve structures with MnFe and MnNi pinning layers were examined and the technique proved particularly useful in identifying regions of the spin valve corrupted by corrosion of the pinning layer.

Five problems on undulator radiation and their solutions are presented. These problems use relativistic mechanics to show how electrons can be induced to emit electromagnetic radiation in a narrow, bright beam with a well-defined wavelength. The electrons are deflected back and forth in a configuration of magnets known as an undulator. The problems collectively demonstrate the importance of the special relativity theory to contemporary accelerator technology.

A close comparison is presented between special relativity and optics of stratified planar media. This presentation, which may provide some useful tools in optics, can also suggest interesting thoughts and questions both in optics, in special relativity, and in quantum theory.

The existence of the Lorentz force in highly-textured and bulk samples of yttrium barium copper oxide samples was investigated. This involved the utilization of a conventional four terminal measurement configuration to determine the resistivity ratio, critical temperature and critical current density (Jc) of the samples. Results indicate that the angular variation of Jc is qualitatively consistent to the expected variation from the functioning of the Lorentz force upon the vortices.

The remanent stales and reversal behavior of 10-nm-thick polyeryslalline Co elements have been investigated using off-axis electron holography and Lorentz microscopy. Different shapes with dimensions in the range of 100-1200 nm were observed, including rectangles with different size and aspect ratio as well as rings and slotted rings. Virgin states of circular and rectangular elements showed a variety of patterns including centered and off-centered vortices. At remanence, rectangles with rounded edges revealed multiple domains separated by a domain wall running transverse to the longer axis. The magnetization reversal behavior of rectangles with regular edges involved S-shaped and bidomain states, whereas the reversal mechanism for rectangles with rounded edges involved 'Y' and 'V' shaped domain walls separating the magnetic domains. Reproducible switching was observed when these latter shapes were subjected to repeated field cycles. Index Terms--Magnetization reversal, off-axis electron holography, remanent state, switching.

Motivated by reports of the effect of ion irradiation on the magnetic properties of thin films, this paper outlines a new and possibly advantageous method of patterning magnetic antidot-type arrays by changing the magnetic properties of thin-film NiFe through [Ga.sup.+] implantation rather than by removal of material. Studies of conventional antidot arrays have reported regular remenant states of interest as possible stored bits trapped during hard axis magnetization reversal. In this paper, we report a study of [Ga.sup.+] implanted antidot-type arrays, which also support remanent states during hard and easy axis magnetization reversal. The energetics of the implanted antidot-type array system are considered, and the reason for the different magnetization reversal process in comparison with conventional antidot arrays is speculated to be due to the energy associated with the increased coercivity and domain wall pinning at implantation-induced damage sites. Index Terms--Antidot array, FIB Ga implantation, Lorentz microscopy, patterned media.

A study was conducted to analyze the magnetization distributions of an array of small NiFe elements. Lorentz transmission electron microscopy and magnetic force microscopy were utilized to carry out the analysis. The samples were made using electron beam lithography and lift-off patterning on electron transparent Si3Ni4 membrane substrates. Experimental results indicated different facets of the magnetization distributions on soft magnetic thin films.

A new and simple method is presented for integrating the equations of motion of a classical relativistic particle subject to a Lorentz force, given electromagnetic fields that are constant in space-time. This integration method leads naturally to a manifestly covariant form of solution.

Relativistic transformation equations for the 3-vector force are derived from the Lorentz force law by using the well-known transformation equations for electromagnetic fields and velocity. The derivation is a simple alternative to the conventional derivation based on relativistic expressions for energy and momentum.

The solution to a problem involving the calculation of the kinetic energy of a particle moving in a potential well with the use of Galilean transformation, Lorentz transformation and special relativity is discussed. The kinetic energy of a particle falling in a potential well is higher than the potential energy stipulated of the potential well's height. Energy of the particles in quantum wells are essential in particle accelerators, cosmic ray travels and generation of solar winds and aurora borealis.

The description of oscillations of electron liquid in large metallic nanospheres is put together within random-phase-approximation semiclassical scheme in jellium model with retardation included by Lorentz friction. The Lorentz friction due to irradiation of electromagnetic wave by plasmon oscillations is examined with respect to the sphere dimension, where the resulting shift in resonance frequency is very sensitive to the sphere radius.

The article studies generalized Lorentzian (kappa) distribution function (DF) to stimulate the electron DF using Vlasov equation. Findings reveal that to increase the population of energetic electrons, the expansion takes place faster.

The development of a new model based on generalization of the classical Lorentz procedure to two dimensions which is able to deal with electrically thin slabs made of small resonant closed current loops is presented. The results obtained from the model are validated by full-wave electromagnetic simulations and compared with the continuous model approximation of the slab.

The problem of the reflection of a plane wave at normal incidence to a perfectly conducting mirror with uniform proper acceleration is investigated. The reflected wave is found to be frequency chirped, as expected, but with the somewhat surprising feature that its amplitude decreases rapidly (as [z.sup.-2]) with distance. In order to fully elucidate the underlying physics involved, this result is obtained by two different methods, one employing the Rindler transform and one employing the Lorentz transform.

The calculations of the vibrational spectrum of HD2 in its first-excited electronic state are reported by using a coordinate-transformation technique. The implications of the geometric phase effect in the spectrum are investigated. The results show that the lowest 45 vibrational levels calculated using the traditional Longuet-Higgins phase are in good agreement with those obtained using a single-surface generalized Born-Oppenheimer equation.

A new derivation is presented for the analytical inversion of aerosol spectral extinction data to size distributions. It is based on the complex analytic extension of the anomalous diffraction approximation (ADA). We derive inverse formulas that are applicable to homogeneous nonabsorbing and absorbing spherical particles. Our method simplifies, generalizes, and unifies a number of results obtained previously in the literature. In particular, we clarify the connection between the ADA transform and the Fourier and Laplace transforms. Also, the effect of the particle refractive-index dispersion on the inversion is examined. It is shown that, when Lorentz's model is used for this dispersion, the continuous ADA inverse transform is mathematically well posed, whereas with a constant refractive index it is ill posed. Further, a condition is given, in terms of Lorentz parameters, for which the continuous inverse operator does not amplify the error. [C] 2000 Optical Society of America OCIS codes: 010.1110, 010.1310, 290.3200, 290.2200.