Showing papers on "Electric field published in 1995"
TL;DR: Field emission of electrons from individually mounted carbon nanotubes has been found to be dramatically enhanced when the nanotube tips are opened by laser evaporation or oxidative etching, in a process that resembles unraveling the sleeve of a sweater.
Abstract: Field emission of electrons from individually mounted carbon nanotubes has been found to be dramatically enhanced when the nanotube tips are opened by laser evaporation or oxidative etching. Emission currents of 0.1 to 1 microampere were readily obtained at room temperature with bias voltages of less than 80 volts. The emitting structures are concluded to be linear chains of carbon atoms, Cn, (n = 10 to 100), pulled out from the open edges of the graphene wall layers of the nanotube by the force of the electric field, in a process that resembles unraveling the sleeve of a sweater.
1,538 citations
TL;DR: In this article, lead lanthanum zirconate titanate (PLZT) was loaded with compressive stress parallel to the polarization and the stress vs strain curve was recorded.
Abstract: Ferroelectric and ferroelastic switching cause ferroelectric ceramics to depolarize and deform when subjected to excessive electric field or stress. Switching is the source of the classic butterfly shaped strain vs electric field curves and the corresponding electric displacement vs electric field loops [1]. It is also the source of a stress—strain curve with linear elastic behavior at low stress, non-linear switching strain at intermediate stress, and linear elastic behavior at high stress [2, 3]. In this work, ceramic lead lanthanum zirconate titanate (PLZT) is polarized by loading with a strong electric field. The resulting strain and polarization hysteresis loops are recorded. The polarized sample is then loaded with compressive stress parallel to the polarization and the stress vs strain curve is recorded. The experimental results are modeled with a computer simulation of the ceramic microstructure. The polarization and strain for an individual grain are predicted from the imposed electric field and stress through a Preisach hysteresis model. The response of the bulk ceramic to applied loads is predicted by averaging the response of individual grains that are considered to be statistically random in orientation. The observed strain and electric displacement hysteresis loops and the nonlinear stress—strain curve for the polycrystalline ceramic are reproduced by the simulation.
651 citations
TL;DR: These are directional superpositions of field-free states corresponding to oblate spheroidal wave functions, with eigenenergies that decrease with increasing field strength, demonstrating the utility of these states for both laser alignment and spatial trapping of molecules.
Abstract: The anisotropic interaction of the electric field vector of intense laser radiation with the dipole moment induced in a polarizable molecule by the laser field creates aligned pendular states. These are directional superpositions of field-free states, corresponding to oblate spheroidal wave functions, with eigenenergies that decrease with increasing field strength. We present calculations demonstrating the utility of these states for both laser alignment and spatial trapping of molecules.
643 citations
TL;DR: In this article, an equation for the threshold transition of liquid crystals was derived using the continuum elastic theory and an inversely proportional relationship between the threshold voltage and the gap between the substrates was found to hold.
Abstract: Electro‐optical characteristics related to the threshold behavior of liquid crystals when using the in‐plane switching (IPS) mode were investigated with interdigital electrodes. In order to analyze the switching behavior of liquid crystals, an equation, which expresses the threshold transition, was derived using the continuum elastic theory. It was made clear that it was the electric field and not the voltage that drives the liquid crystals in the IPS mode. Significantly, an inversely proportional relationship between the threshold voltage and the gap between the substrates was found to hold. Furthermore, the electro‐optical characteristics were recognized to change with the variation of the gap between the substrates. This behavior is due to the independence of electric field on liquid crystal layer normal.
603 citations
TL;DR: In this paper, the authors show that magnetic reconnection may also occur in three dimensions in the absence of neutral points at so-called quasi-separatrix layers, where there is a steep gradient in field line linkage.
Abstract: In two or three dimensions, magnetic reconnection may occur at neutral points and is accompanied by the transport of magnetic field lines across separatrices, the field lines (or flux surfaces in three dimensions) at which the mapping of field lines is discontinuous. Here we show that reconnection may also occur in three dimensions in the absence of neutral points at so-called “quasi-separatrix layers,” where there is a steep gradient in field line linkage. Reconnection is a global property, and so, in order to determine where it can occur, the first step is to enclose the volume being considered by a boundary (such as a spherical surface). Then the mapping of field lines from one part of the boundary to another is determined, and quasi-separatrix layers may be identified as regions where the gradient of the mapping or its inverse is very much larger than normal. The most effective measure of the presence of such layers is the norm of the displacement gradient tensor; their qualitative location is robust and insensitive to the particular surface that is chosen. Reconnection itself occurs when there is a breakdown of ideal MHD and a change of connectivity of plasma elements, where the field line velocity becomes larger than the plasma velocity, so that the field lines slip through the plasma. This breakdown can occur in the quasi-separatrix layers with an electric field component parallel to the magnetic field. In three dimensions the electric field E (and therefore the field line velocity v⊥) depends partly on the imposed values of E (or v⊥) at the boundary and partly on the gradients of the inverse mapping function. We show that the inverse mapping determines the location of the narrow layers where the breakdown of ideal MHD can occur, while the imposed boundary values of v⊥ determine mainly the detailed flow pattern inside the layers. Thus, in general, E (and therefore v⊥) becomes much larger than its boundary values at locations where the gradients of the inverse mapping function are large. An example is given of a sheared X field, where a slow smooth continuous shear flow imposed on the boundary across one quasi-separatrix produces a flipping of magnetic field lines as they slip rapidly through the plasma in the other quasi-separatrix layer. It results in a strong plasma jetting localized in, and parallel to, the separatrix layers.
481 citations
TL;DR: In this paper, a model of the high-latitude electric potentials was developed from measurements of the electric field on the DE 2 satellite, using all polar cap passes during which high-resolution IMF data were available from the ISEE 3 or IMP 8 satellites.
Abstract: New models of the high-latitude electric potentials have been developed. These models show how the polar ionospheric electric field, or plasma convection, responds to changes in the interplanetary magnetic field (IMF) and other parameters, such as dipole tilt angle. These patterns were derived from measurements of the electric field on the DE 2 satellite, using all polar cap passes during which high-resolution IMF data were available from the ISEE 3 or IMP 8 satellites. The data are sorted according to the angle of the IMF in the GSM Y-Z plane. The measurements are further divided into different groups according to the magnitude of the IMF or the dipole tilt angle. All measurements in each group are then used to derive a model of the electric potential for the given conditions, using a new technique where the coefficients of a spherical harmonic expansion are found by least square error fits. The resulting convection patterns are very realistic and show consistent variations as the IMF BY/BZ angle rotates. For northward IMF (positive BZ) evidently there are four convection “cells,” rather than a distortion of the two-cell pattern. Many other useful facts regarding the solar wind-ionosphere coupling can be extracted from the derived patterns, such as the relationship between the polar cap potential drop and the IMF clock angle.
472 citations
TL;DR: The static electric polarizability tensor of single-wall carbon nanotubes is calculated within the random-phase approximation using a simple tight-binding model and a classical correction to include local fields to suggest that under the application of a randomly oriented electric field, nanot tubes acquire dipole moments pointing mainly along their axes.
Abstract: The static electric polarizability tensor of single-wall carbon nanotubes is calculated within the random-phase approximation using a simple tight-binding model and a classical correction to include local fields. We find that the polarizability for constant fields parallel to the cylindrical axis is highly dependent on the details of the tube`s electronic structure. In contrast, the polarizability for fields perpendicular to the axis only depends on the tube radius. The relative magnitudes of these two quantities suggests that under the application of a randomly oriented electric field, nanotubes acquire dipole moments pointing mainly along their axes, with the size of the dipole inversely proportional to the square of the minimum direct band gap.
425 citations
TL;DR: In this article, the drift mobility of electrons and holes in thin, vapordeposited films of tris(8−hydroxyquinolinolato•N1,O8) aluminum using a time of flight photoconductivity technique was measured.
Abstract: We have measured the drift mobility of electrons and holes in thin, vapor‐deposited films of tris(8‐hydroxyquinolinolato‐N1,O8) aluminum using a time of flight photoconductivity technique. The drift of mobility of both carriers is dispersive and strongly electric field and temperature dependent. At ambient temperature and an electric field of 4×105 V cm−1, the effective mobility of electrons and holes is 1.4×10−6 and 2×10−8 cm2 V−1 s−1, respectively, in a 400 nm thick sample.
402 citations
01 May 1995
TL;DR: A non-contact sensor based on the interaction of a person with electric fields for human-computer interface is investigated and empirical and analytical approaches to transform sensor measurements into position information are discussed.
Abstract: A non-contact sensor based on the interaction of a person with electric fields for human-computer interface is investigated. Two sensing modes are explored: an external electric field shunted to ground through a human body, and an external electric field transmitted through a human body to stationary receivers. The sensors are low power (milliwatts), high resolution (millimeter) low cost (a few dollars per channel), have low latency (millisecond), high update rate (1 kHz), high immunity to noise (>72 dB), are not affected by clothing, surface texture or reflectivity, and can operate on length scales from microns to meters. Systems incorporating the sensors include a finger mouse, a room that knows the location of its occupant, and people-sensing furniture. Haptic feedback using passive materials is described. Also discussed are empirical and analytical approaches to transform sensor measurements into position information.
346 citations
01 Jan 1995
TL;DR: In this paper, it was shown that the strong field science and short pulse science are two fields which will become increasingly intertwined and that efficient rapid excitation requires increasingly higher intensities as can be seen from the simple example of a resonantly driven two-level system.
Abstract: Current laser technology is capable of generating laser fields from the IR to visible wavelength regions in the form of well-tailored sequences of pulses with controllable phase and envelopes (pulse shape) [1–2]. Such pulses can be used for the efficient preparation of ensembles of atoms or molecules in specific states. This is of considerable interest not only in spectroscopy but also in studies of chemical dynamics [2–4]. Furthermore short pulses allow one to attain electric field strengths e (V cm-1) or equivalently laser intensities I (W/cm2) = ce 2 /8π (c = velocity of light) which are comparable or greater than atomic fields. An important consequence of the progress in this area is that one can greatly enhance radiative transition rates and even ionize molecules. Clearly strong field science and short pulse science are two fields which will become increasingly intertwined. Efficient rapid excitation requires increasingly higher intensities as can be seen from the simple example of a resonantly driven two-level system [6–7].
307 citations
TL;DR: In this article, the authors used extensive radar measurements of F region vertical plasma drifts and auroral electrojet indices to determine the storm time dependence of equatorial zonal electric fields.
Abstract: The authors use extensive radar measurements of F region vertical plasma drifts and auroral electrojet indices to determine the storm time dependence of equatorial zonal electric fields. These disturbance drifts result from the prompt penetration of high latitude electric fields and from the dynamo action of storm time winds which produce the largest perturbations a few hours after the onset of magnetic activity. The signatures of the equatorial disturbance electric fields change significantly depending on the relative contributions of these two components. The prompt electric field responses, with lifetimes of about one hour, are in excellent agreement with results from global convection models. The electric fields generated by storm time winds have longer lifetimes, amplitudes proportional to the energy input into the high latitude ionosphere, and a daily variation which follows closely the disturbance dynamo pattern of Blanc and Richmond. The storm wind driven electric fields are responsible for the larger amplitudes and longer lifetimes of the drift perturbations following sudden decreases in convection compared to those associated with sudden convection enhancements. 14 refs., 6 figs., 1 tab.
TL;DR: In this paper, the authors present a review of the work on measuring electric fields in semiconductors with a particular emphasis on microstructures using the specialized layer sequence, and discuss the general theory of modulation techniques and their relevance.
Abstract: In the presence of an electric field, the dielectric constant of a semiconductor exhibits Franz–Keldysh oscillations (FKO), which can be detected by modulated reflectance. Although it could be a powerful and simple method to study the electric fields/charge distributions in various semiconductor structures, in the past it has proven to be more complex. This is due to nonuniform fields and impurity induced broadening, which reduce the number of detectible Franz–Keldysh oscillations, and introduce uncertainties into the measurement. In 1989, a new structure, surface–undoped–doped (s‐i‐n+/s‐i‐p+) was developed, which allows the observation of a large number of FKOs and, hence, permitting accurate determination of electric fields. We present a review of the work on measuring electric fields in semiconductors with a particular emphasis on microstructures using the specialized layer sequence. We first discuss the general theory of modulation techniques dwelling on the approximations and their relevance. The cas...
Abstract: Diamond samples with varying defect densities have been synthesized by chemical vapor deposition, and their field emission characteristics have been investigated. Vacuum electron field emission measurements indicate that the threshold electric field required to generate sufficient emission current densities for flat panel display applications (≳10 mA/cm2) can be significantly reduced when the diamond is grown so as to contain a substantial number of structural defects. The defective diamond has a Raman spectrum with a broadened peak at 1332 cm−1 with a full width at half maximum (FWHM) of 7–11 cm−1. We establish a strong correlation between the field required for emission and the FWHM of the diamond peak. The threshold fields are typically less than 50 V/μm and can reach as low as 30 V/μm for diamond with a FWHM greater than 8.5 cm−1. It is believed that the defects create additional energy bands within the band gap of diamond and thus contribute electrons for emission at low electric fields.
TL;DR: In this paper, the formation of steady convective rolls and their morphology as a function of the slab thickness were characterized, showing that these rolls can be used to generate net currents and forces, even for zero average surface charge density.
Abstract: The electro-osmotic flow generated by an electric field ${\stackrel{\ensuremath{\rightarrow}}{E}}_{\mathrm{ext}}$ in a fluid bounded by surfaces bearing a charge varying in space is considered. Focusing on a slab geometry, I characterize the formation of steady convective rolls and describe their morphology as a function of the slab thickness. These rolls can be used to generate net currents and forces, even for zero average surface charge density. Moreover, the current (or the force) can be perpendicular to the applied field, opening the way to a variety of microscopic electromechanical devices.
TL;DR: In this paper, the microwave surface resistance (30-60 GHz) for different crystallographic orientations in the vortex state was measured and a sharp magnetoabsorption resonance was observed.
Abstract: We have measured the microwave surface resistance (30-60 GHz) for different crystallographic orientations in the vortex state of ${\mathrm{Bi}}_{2}{\mathrm{Sr}}_{2}\mathrm{Ca}{\mathrm{Cu}}_{2}{\mathrm{O}}_{8+\ensuremath{\delta}}$. A sharp magnetoabsorption resonance is observed below ${T}_{c}$ when ac electric fields and magnetic fields are applied parallel to the $c$ axis (${E}_{\mathrm{ac}}\ensuremath{\parallel}B\ensuremath{\parallel}c$). We argue that the observed resonance arises from collective Josephson plasma oscillations generated by interlayer Josephson currents. From the frequency and temperature dependence of the resonance, we discuss the interlayer phase coherence in the vortex liquid and solid states quantitatively.
TL;DR: In this paper, the authors show that the electric field inside storms tends to be limited to magnitudes less than or equal to the breakeven field, which may explain why electric field magnitudes greater than 150 kV m−1 are rarely found inside thunderstorms.
Abstract: Lightning may be initiated via an electron avalanche that may occur when energetic electrons (∼1 MeV) are accelerated by thunderstorm electric fields to velocities sufficient to produce new energetic electrons during ionizing collisions with nitrogen or oxygen molecules. For the avalanche to occur, the thunderstorm electric field must exceed a critical value called the breakeven field. At any altitude the breakeven field is substantially less than the field usually thought necessary either for dielectric breakdown or for streamer propagation. We show that 23 electric field soundings through thunderstorms seem to confirm that lightning occurs when the electric field exceeds the breakeven field. The soundings also show that the electric field inside storms tends to be limited to magnitudes less than or equal to the breakeven field. This breakeven mechanism may explain why electric field magnitudes greater than 150 kV m−1 are rarely found inside thunderstorms. It may also help explain the initiation of lightning and other types of discharges that either propagate upward from the tops of thunderstorms or occur above them.
TL;DR: In this article, the authors demonstrate that correlation of the energies of sites close together can lead to field dependences similar to the Poole-Frenkel one over a wide range of fields where it is usually seen experimentally.
Patent•
08 Dec 1995
TL;DR: In this article, a method for treating materials, especially organic materials, with pulsed electrical fields, wherein the method includes the step of applying an agile pulse sequence having at least three pulses to a material, was described.
Abstract: A method is provided for treating materials, especially organic materials, with pulsed electrical fields, wherein the method includes the step of applying an agile pulse sequence having at least three pulses to a material, wherein the agile pulse sequence has one, two, or three of the following characteristics: (1) at least two of the at least three pulses differ from each other in pulse amplitude; (2) at least two of the at least three pulses differ from each other in pulse width; and (3) a first pulse interval for a first set of two of the at least three pulses is different from a second pulse interval for a second set of two of the at least three pulses. When biological cells are treated to form pores in an electroporation procedure, the induced pores are sustained for a relatively long period of time, and viability of the biological cells is maintained.
Patent•
07 Sep 1995
TL;DR: In this article, an electric field is applied across the periodic structure, a Bragg grating is formed by the electro-optic effect, reflecting optical radiation with a certain bandwidth around a center wavelength.
Abstract: Method for optical energy transfer and energy guidance uses an electric field (34) to control energy propagation (44) using a class of poled structures (39) in solid material (25). The poled structures, which may form gratings in thin film or bulk configurations, may be combined with waveguide structures. Electric fields are applied to the poled structures to control routing of optical energy. Techniques include frequency-selective switchable- and adjustable-tunable reflection, splitting, directional coupling, frequency-tunable switching and efficient beam combining, as well as polarized beam combining. Adjustable tunability is obtained by a poled structure which produces a spatial gradient in a variable index of refraction along an axis in the presence of a variable electric field. In one embodiment, the present invention is a method of switching a grating (48) which consists of a poled material with an alternating domain structure of specific period. When an electric field is applied across the periodic structure, a Bragg grating is formed by the electro-optic effect, reflecting optical radiation with a certain bandwidth around a center wavelength.
TL;DR: Continuous separation and extraction of two cell types can be achieved by repeated reversing of the fluid flow direction in phase with the switching on and off of the applied voltage, and the efficacy of the technique is demonstrated for viable and nonviable (heat‐treated) yeast cells.
Abstract: Dielectrophoresis is the movement of particles in non-uniform alternating and direct current (AC, DC) electric fields. When nonuniform electric fields are created between microelectrodes, cells will redistribute themselves around the electrodes, the force holding the cells in place dependig on the local electric field and on the electrical properties of the cells themselves and the suspending medium. Steric drag forces produced by a gentle fluid flow in the chamber can be used to separate cells by selectively lifting cells from potential energy wells produced by the electric field. The technique is demonstrated in the batch separation of bacteria, yeast cells, and plant cells. Continuous separation and extraction of two cell types can be achieved by repeated reversing of the fluid flow direction in phase with the switching on and off of the applied voltage, and the efficacy of the technique is demonstrated for viable and nonviable (heat-treated) yeast cells. (c) 1995 John Wiley & Sons, Inc.
TL;DR: In this paper, the potential difference between an electric field probe and its spacecraft (with conductive surfaces) can be used to determine the ambient electron density and/or electron flux with limited accuracy but with high time resolution, of the order of 10-100 ms.
Abstract: . Several satellites (GEOS-1, GEOS-2, ISEE-1, Viking and CRRES) carried electric field experiments on which probes were driven by a current from the satellite to be close to the plasma potential. The potential difference between an electric field probe and its spacecraft (with conductive surfaces) can be used to determine the ambient electron density and/or electron flux with limited accuracy but with high time resolution, of the order of 10-100 ms. It is necessary for the development of this diagnostic method to understand the photoemission characteristics of probes and satellites. According to the electric field experiments on the above-mentioned satellites, all materials develop very similar photoemission properties when they are beyond the influence of atmospheric oxygen. The photoelectron yield steadily increases over the first few months in space and reaches values well above those measured on clean surfaces in the laboratory. The method can be used for solar radiation levels corresponding to distances from 0.4 to 5 AU from the Sun.
TL;DR: In this paper, the expansion phase of substorms results from a reduction in the large-scale electric field imparted to the magnetosphere from the solar wind, following a ≳ 30-min growth phase due to an enhancement in this electric field.
Abstract: It is proposed here that the expansion phase of substorms results from a reduction in the large-scale electric field imparted to the magnetosphere from the solar wind, following a ≳ 30-min growth phase due to an enhancement in this electric field. The reduction in the electric field is assumed to propagate antisunward within the magnetosphere. Triggering by a reduction in the electric field is suggested by the observation that substorms are often triggered by northward turnings of the interplanetary magnetic field (IMF). However, under the theory presented here, substorms may be triggered by anything that causes an electric field reduction such as a reduction in the magnitude of the y component of the IMF. A reduction in the large-scale electric field disrupts both the inward motion and energization of plasma sheet particles that occurs during the growth phase. It is suggested here that this can lead to formation of the expansion phase current wedge and active aurora. The current wedge results from the magnetic drift of ions, which has a speed proportional to particle energy, and a large azimuthal gradient in mean particle energy that is expected to develop in the vicinity of magnetic midnight during the growth phase. Current wedge formation will most likely be initiated near the radial distance (∼6-10 RE) of the peak in the growth phase plasma pressure distribution, and then propagate tailward from that region. Order-of-magnitude calculations show that the above proposal can account for the rapid development of the expansion phase relative to the growth phase, the magnitude of the reduction in the cross-tail current within the current wedge, the speeds of tailward and westward expansion of the current reduction region, the speeds of poleward and westward motion of active aurora in the ionosphere, and the magnitude of wedge field-aligned currents that connect the ionospheric region of active auroral to the divergent cross-tail current within the magnetosphere.
TL;DR: The response of an infinite, periodic, insulating, solid to an infinitesimally small electric field is investigated in the framework of Density Functional Theory and it is found that the applied perturbing potential is not a unique functional of the periodic density change but depends also on the change in the macroscopic polarization.
Abstract: The response of an infinite, periodic, insulating, solid to an infinitesimally small electric field is investigated in the framework of Density Functional Theory. We find that the applied perturbing potential is not a unique functional of the periodic density change~: it depends also on the change in the macroscopic {\em polarization}. Moreover, the dependence of the exchange-correlation energy on polarization induces an exchange-correlation electric field. These effects are exhibited for a model semiconductor. We also show that the scissor-operator technique is an approximate way of bypassing this polarization dependence.
TL;DR: The Polar satellite carries a system of four wire booms in the spacecraft spin plane and two rigid booms along the spin axis, each of the booms has a spherical sensor at its tip along with nearby guard and stub surfaces whose potentials relative to that of their sphere are controlled by associated electronics.
Abstract: The Polar satellite carries a system of four wire booms in the spacecraft spin plane and two rigid booms along the spin axis. Each of the booms has a spherical sensor at its tip along with nearby guard and stub surfaces whose potentials relative to that of their sphere are controlled by associated electronics. The potential differences between opposite sphere pairs are measured to yield the three components of the DC to >1 MHz electric field. Spheres can also be operated in a mode in which their collected current is measured to give information on the plasma density and its fluctuations. The scientific studies to be performed by this experiment as well as the mechanical and electrical properties of the detector system are described.
TL;DR: In this article, the anisotropic interaction of the electric field vector of intense laser radiation with the dipole moment induced in apolarizuble molecules by the laser field creates aligned pendular states.
Abstract: The anisotropic interaction of the electric field vector of intense laser radiation with the dipole moment induced in apolarizuble molecule by the laser field creates aligned pendular states These are directional superpositions of field-free states, governed by a cos2 8 potential (with 8 the angle between the molecular axis and the field vector) We show that the spatial alignment and other eigenproperties can be derived from spheroidal wave functions, give explicit expressions for low- and high-field limits, contrast the induced pendular states with those for permanent dipoles subject to static fields, and present calculations demonstrating the utility of the induced states for rotational spectroscopy, laser alignment, and spatial trapping of molecules
TL;DR: In this paper, the authors observed significant field emission from the surface of nanofilament carbon structure films on various substrates (Si, quartz, glass) while the electric field was about 100 V/μm.
TL;DR: In this article, stable growth of cracks with either conducting or insulating interiors is observed in 8/65/35 lanthanum lead zirconate titanate samples.
Abstract: Ferroelectric ceramics are susceptible to fracture under high magnitude cyclic electric field. Flaws concentrate the electric field, inducing a large incompatible strain, and thereby a large stress. Stable growth of cracks with either conducting or insulating interiors is observed in 8/65/35 lanthanum lead zirconate titanate samples. Indentations on the electroded surface are filled with distilled water or a water-salt solution. Under cyclic electric field, tree like damage grows from the indented electrode. Indentations on the surfaces 90° to the electrodes are filled with silicone oil. This results in stable crack growth perpendicular to the cyclic electric field. Nonlinear fracture models are presented for both conducting and insulating cracks. Tensile stress intensity factors are predicted for both cases.
TL;DR: A series of peaks seen in the calculated proton energy spectra can be interpreted as occurring preferentially at (i) turning points of laser-induced vibrationally trapped states, and (ii) at the ionization maxima that occur at large internuclear distances of H{sub 2}{sup +}.
Abstract: The time-dependent Schr\"odinger equation for ${\mathrm{H}}_{2}^{+}$ in a strong laser field is solved numerically for a model that uses the exact three-body Hamiltonian with one-dimensional nuclear motion restricted to the direction of the laser electric field. The influence of ionization on possible stabilization against dissociation is investigated. Unexpectedly high ionization rates from high vibrational states, exceeding those of neutral atomic hydrogen, are found. The ionization rates as functions of the internuclear distance R were also calculated for fixed nuclei, and these exhibit two strong maxima at large R, which explain the full dynamical results. A series of peaks seen in the calculated proton energy spectra can therefore be interpreted as occurring preferentially at (i) turning points of laser-induced vibrationally trapped states, and (ii) at the ionization maxima that occur at large internuclear distances of ${\mathrm{H}}_{2}^{+}$.
TL;DR: The electric field E induced in type-II superconductors during the penetration of magnetic flux exhibits a strange profile when the sample has the usual square or rectangular cross section perpendicular to the applied field.
Abstract: The electric field E induced in type-II superconductors during the penetration of magnetic flux exhibits a strange profile when the sample has the usual square or rectangular cross section perpendicular to the applied field ${\mathit{B}}_{\mathit{a}}$(t). For example, in the Bean critical state with full penetration of the current density j, though j=${\mathit{j}}_{\mathit{c}}$ is constant, E is not constant but is a linear function of space directed along concentric rectangles (like j) with magnitude E exhibiting a zig-zag-folded profile with (a) sharp minima with E=0 along the discontinuity lines where the current flow bends, (b) sharp maxima along the median of the short sides, and (c) sharp folds along two lines which are at a distance of half the short side from the short side. This fold defines new discontinuity lines occurring in regions where the current flow is quasihomogeneous. The resulting electric charge density q=${\mathrm{\ensuremath{\epsilon}}}_{0}$divE is piecewise constant in twelve sections of the rectangle where it is either zero or q=\ifmmode\pm\else\textpm\fi{}${\mathrm{\ensuremath{\epsilon}}}_{0}$\ensuremath{\partial}${\mathit{B}}_{\mathit{a}}$/\ensuremath{\partial}t. These exotic features of E apply to arbitrary specimen thickness, unlike the current density and the magnetic field, which during flux penetration or exit are qualitatively different in longitudinal and transverse geometries. From a nonlinear diffusion equation, which is local for longitudinal and nonlocal for transverse geometry, the current density, magnetic, and electric fields, vortex velocity, charge density, and local energy dissipation are calculated for penetration and creep of longitudinal or transverse flux in slabs, strips, rectangular bars, and rectangular films or plates of a superconductor which is characterized by a highly nonlinear resistivity.