Electron dynamics in one-dimensional double layers

1985 ◽  
Vol 34 (2) ◽  
pp. 271-288 ◽  
Author(s):  
Takashi Yamamoto
Keyword(s):  
Double Layer ◽  
Temporal Evolution ◽  
Dynamical Behaviour ◽  
Double Layers ◽  
Electron Dynamics ◽  
Nonlinear Scattering ◽  
Plasma Oscillations ◽  
One Dimensional ◽  
Simulation Results ◽  
Double Layer Thickness

By numerical simulations, the dynamical behaviour of the electrons in one-dimensional double layers is studied. The simulation results show that at least one third of the electrons emitted at the low-potential boundary of the simulation system are reflected back before passing through the double layers. Such reflexion is due to (i) quasi-linear or nonlinear scattering by plasma oscillations and (ii) ambipolar potentials observed around the potential front of the localized double layer. The whole temporal evolution of the localized double layers are also presented. In particular, we attempt to explain the steepening and collapsing of the localized double layers in terms of the formula for the double-layer thickness.

The primary electroviscous effect in a suspension of spheres with thin double layers

1983 ◽  
Vol 132 ◽  
pp. 337-347 ◽  
Author(s):  
E. J. Hinch ◽  
J. D. Sherwood
Keyword(s):  
Layer Thickness ◽  
Double Layer ◽  
High Surface ◽  
Particle Radius ◽  
Double Layers ◽  
Asymptotic Results ◽  
Electroviscous Effect ◽  
Surface Potentials ◽  
Double Layer Thickness

We study the primary electroviscous effect in a suspension of spheres when the double layer thickness κ−1 is small compared with the particle radius a. The case of a 1–1 symmetric electrolyte is examined using the methods of Dukhin & coworkers (1974), whilst the asymmetric electrolyte is studied along lines similar to those of O'Brien (1983). Sherwood's (1980) asymptotic results for high surface potentials and high Hartmann numbers are extended and complemented.

Synthesis and crystal structures of some bis(3-methyl-1H-indol-2-yl)(salicyl)methanes

2019 ◽  
Vol 75 (1) ◽  
pp. 65-69
Author(s):  
Wyatt Cole ◽  
Stephanie L. Hemmingson ◽  
Audrey C. Eisenberg ◽  
Catherine A. Ulman ◽  
Joseph M. Tanski ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Dimethyl Sulfoxide ◽  
Crystal Structures ◽  
Double Layer ◽  
Acid Catalysis ◽  
Double Layers ◽  
One Dimensional ◽  
Salicylaldehyde Derivatives ◽  
Central Carbon ◽  
Solvent Molecules

Four 2,2′-bisindolylmethanes (BIMs), a useful class of polyindolyl species joined to a central carbon, were synthesized using salicylaldehyde derivatives and simple acid catalysis; these are 2-[bis(3-methyl-1H-indol-2-yl)methyl]-6-methylphenol, (IIa), 2-[bis(3-methyl-1H-indol-2-yl)methyl]-4,6-dichlorophenol, (IIb), 2-[bis(3-methyl-1H-indol-2-yl)methyl]-4-nitrophenol, (IIc), and 2-[bis(3-methyl-1H-indol-2-yl)methyl]-4,6-di-tert-butylphenol, (IId). BIMs (IIa) and (IIb) were characterized crystallographically as the dimethyl sulfoxide (DMSO) disolvates, i.e. C26H24N2O·2C2H6OS and C25H20Cl2N2O·2C2H6OS, respectively. Both form strikingly similar one-dimensional hydrogen-bonding chain motifs with the DMSO solvent molecules. BIM (IIa) packs into double layers of chains whose orientations alternate every double layer, while (IIb) forms more simply packed chains along the a axis. BIM (IIa) has a remarkably long c axis.

Numerical model of plasma double layers using the Vlasov equation

1980 ◽  
Vol 23 (3) ◽  
pp. 433-452 ◽  
Author(s):  
Lloyd E. Johnson
Keyword(s):  
Magnetic Field ◽  
Double Layer ◽  
Axial Magnetic Field ◽  
Double Layers ◽  
Plasma Region ◽  
Langmuir Waves ◽  
One Dimensional ◽  
Poisson Equations ◽  
The One ◽  
Do So

The one-dimensional plasma double layer is modelled by numerically integrating the time-dependent Vlasov and Poisson equations. A constant magnetic field at an arbitrary angle with respect to the layer is included. The model shows that such a plasma region can generate as well as reflect Langmuir waves and shows how RF emission may arise. An axial magnetic field does not inhibit the formation of a double layer, although a non-axial field may do so.

Numerical simulation of plasma double layers

1978 ◽  
Vol 20 (3) ◽  
pp. 391-404 ◽  
Author(s):  
Glenn Joyce ◽  
Richard F. Hubbard
Keyword(s):  
Numerical Simulation ◽  
Double Layer ◽  
Constant Velocity ◽  
Single Pulse ◽  
Potential Drop ◽  
Ion Beams ◽  
Spatial Extent ◽  
Double Layers ◽  
Limited Region ◽  
One Dimensional

The results of a numerical simulation of a plasma double layer are presented. The model is of a finite, one-dimensional plasma with a specified potential difference across the system. Initially a single pulse is formed which traverses the system with constant velocity. This stage is followed by the formation of a potential drop across a limited region of the plasma. The relation between the spatial extent of the double layer and the potential drop is given approximately by L = 6(edgr;φ/kTe)½. The double layer causes electron and ion beams which tend to lead to instabilities in the upstream and downstream regions.

In situ investigation of the stress evolution during deposition of Ti/Al-multi layer films as a function of layer thickness and substrate temperature.

2002 ◽  
Vol 749 ◽  
Author(s):  
St. Lackner ◽  
R. Abermann
Keyword(s):  
Tensile Stress ◽  
Substrate Temperature ◽  
Layer Thickness ◽  
Double Layer ◽  
Multilayer Film ◽  
Multilayer Films ◽  
Double Layers ◽  
Al Alloy ◽  
Double Layer Thickness

ABSTRACTIn order to further investigate the origin of growth instabilities in aluminium rich Ti/Al-alloy films, formed by simultaneous deposition of the two alloy components, from separate evaporation sources, we have investigated the growth stress of multilayer-films under UHV-conditions, formed by a variable number of double layers of Ti and Al, by in situ internal stress measurements. The thickness of the respective Ti/Al-double layer was varied between 6.25 nm and 25 nm and the thickness of the respective titanium and aluminium layer was chosen to achieve an overall composition of Ti25Al75in a 150 nm thick film. The multilayer films were deposited on 10 nm thick alumina substrate films at substrate temperatures of 350°C and 450°C. Microstructure and phase formation was investigated by TEM/TED-experiments.In summary, these experiments show diffusion of aluminium (compressive stress) into the underlying film during deposition of the first monolayers and then formation (stress free or small tensile stress) of aluminium precipitates on the surface of the multilayer film during each aluminium deposition. During the subsequent titanium deposition the aluminium surface precipitates spread in a circular region under alloy formation (tensile stress) (see also accompanying paper). The respective stress contributions are strongly dependent on the double-layer thickness and substrate temperature. The increasing magnitude of the different stress contributions in the early growth stage are interpreted to indicate that the various processes are limited to specific surface regions, which get larger as the number of double-layers increases. The average film stress built up in the respective multilayer film by superposition of the stress contributions mentioned above, is also strongly dependent on double layer thickness and substrate temperature.

scholarly journals Phase-space holes due to electron and ion beams accelerated by a current-driven potential ramp

2003 ◽  
Vol 10 (1/2) ◽  
pp. 37-44 ◽  
Author(s):  
M. V. Goldman ◽  
D. L. Newman ◽  
R. E. Ergun
Keyword(s):  
Phase Space ◽  
Electric Field ◽  
Double Layer ◽  
Ion Beams ◽  
Double Layers ◽  
Open Boundary ◽  
Neutral Density ◽  
One Dimensional ◽  
Slow Moving ◽  
A Current

Abstract. One-dimensional open-boundary simulations have been carried out in a current-carrying plasma seeded with a neutral density depression and with no initial electric field. These simulations show the development of a variety of nonlinear localized electric field structures: double layers (unipolar localized fields), fast electron phase-space holes (bipolar fields) moving in the direction of electrons accelerated by the double layer and trains of slow alternating electron and ion phase-space holes (wave-like fields) moving in the direction of ions accelerated by the double layer. The principal new result in this paper is to show by means of a linear stability analysis that the slow-moving trains of electron and ion holes are likely to be the result of saturation via trapping of a kinetic-Buneman instability driven by the interaction of accelerated ions with unaccelerated electrons.

scholarly journals A fluid description of plasma double-layers

1980 ◽  
Vol 23 (2) ◽  
pp. 223-247 ◽  
Author(s):  
J. S. Levine ◽  
F. W. Crawford
Keyword(s):  
Space Charge ◽  
Double Layer ◽  
Space Plasma ◽  
Double Layers ◽  
Layer Potentials ◽  
One Dimensional ◽  
Electrons And Ions ◽  
Theoretical Predictions ◽  
Fluid Theory ◽  
Valuable Product

This paper describes the space-charge double-layer that forms between two plasmas with different densities and thermal energies. Three progressively more realistic models are treated by fluid theory, taking into account four species of particles: electrons and ions reflected by the double-layer, and electrons and ions transmitted through it. First, the two plasmas are assumed to be cold, and the self-consistent potential, electric field and space-charge distributions within the double-layer are determined. Second, the effects of thermal velocities are taken into account for the reflected particles, and the modifications to the cold plasma solutions are established. Third, the further modifications due to thermal velocities of the transmitted particles are examined. The applicability of a one-dimensional fluid description, rather than plasma kinetic theory, is discussed. One valuable product of this description is the potential difference across the double- layer in terms of the parameters of the two plasmas which it separates. A useful length parameter is defined characterizing the distance over which most of this potential is dropped. Comparisons are then made between theoretical predictions, and double-layer potentials and lengths deduced from laboratory and space plasma experiments.

The simulation of plasma double-layer structures in two dimensions

1983 ◽  
Vol 29 (1) ◽  
pp. 45-84 ◽  
Author(s):  
Joseph E. Borovsky ◽  
Glenn Joyce
Keyword(s):  
Magnetic Field ◽  
Electron Beam ◽  
Double Layer ◽  
Ion Beam ◽  
Two Dimensions ◽  
Distribution Functions ◽  
Double Layers ◽  
Two Dimensional ◽  
One Dimensional ◽  
Electron Cyclotron Waves

Electrostatic plasma double layers are numerically simulated by means of a magnetized 2½-dimensional particle-in-cell method, periodic in one direction and bounded by reservoirs of Maxwellian plasma in the other. The investigation of planar double layers indicates that these one-dimensional potential structures are susceptible to periodic disruption by plasma instabilities. A slight increase in the double-layer thickness with an increase in its obliqueness to the magnetic field is observed. It is noted that weak magnetization results in the double-layer electric-field alignment of particles accelerated by these potential structures and that strong magnetization results in their magnetic-field alignment. Electron-beam-excited electrostatic electron cyclotron waves and ion-beam-driven electrostatic turbulence are present in the plasmas adjacent to the double layers. The numerical simulations of spatially periodic two-dimensional double layers also exhibit cyclical instability. A morphological invariance in two-dimensional double layers with respect to the degree of magnetization implies that the potential structures scale with Debye lengths rather than with gyroradii. Ion-beam-driven electrostatic turbulence and electron-beam-driven plasma waves are again detected. A simplified one-dimensional model of oblique plasma double layers, using water-bag velocity distribution functions, is presented in an appendix.

scholarly journals Linear Vlasov stability in one-dimensional double layers

1987 ◽  
Vol 5 (2) ◽  
pp. 287-293 ◽  
Author(s):  
J. Teichmann
Keyword(s):  
Double Layer ◽  
Analytical Study ◽  
Double Layers ◽  
Poisson System ◽  
One Dimensional ◽  
Poisson Equations ◽  
Self Consistent ◽  
Piecewise Continuous ◽  
The Stability ◽  
High Level

Analytical study of the linear stability of one-dimensional double layers in nonmagnetized plasmas based on the solution of the Vlasov–Poisson system is presented. Electromagnetic effects are not included. A self-consistent equilibrium electrostatic potential Φ0(z) that monotonically increases from a low level at z = − ∞ to a high level at z = + ∞ is assumed. We model this potential as a piecewise continuous function of z and we assume that Φ0(z) has constant values for − ∞ z ≤ 0 and L ≤ z < ∞, L being the thickness of the double layer. The BGK states for the Vlasov–Poisson system provide an explicit expression for the velocity distribution of the reflected electrons required for the particular double layer configuration. The stability of the double layers is studied via the linearized Vlasov and Poisson equations using the WKB approximation.

Cracking at the fold in double layer coated paper: the influence of latex and starch composition

TAPPI Journal ◽  
2019 ◽  
Vol 18 (2) ◽  
pp. 93-99
Author(s):  
SEYYED MOHAMMAD HASHEMI NAJAFI ◽  
DOUGLAS BOUSFIELD, ◽  
MEHDI TAJVIDI
Keyword(s):  
Mechanical Properties ◽  
Double Layer ◽  
Starch Content ◽  
Single Layer ◽  
Double Layers ◽  
Coated Paper ◽  
Coated Papers ◽  
Coating Layers ◽  
Scanned Images ◽  
Packaging Paper

Cracking at the fold of publication and packaging paper grades is a serious problem that can lead to rejection of product. Recent work has revealed some basic mechanisms and the influence of various parameters on the extent of crack area, but no studies are reported using coating layers with known mechanical properties, especially for double-coated systems. In this study, coating layers with different and known mechanical properties were used to characterize crack formation during folding. The coating formulations were applied on two different basis weight papers, and the coated papers were folded. The binder systems in these formulations were different combinations of a styrene-butadiene latex and mixtures of latex and starch for two different pigment volume concentrations (PVC). Both types of papers were coated with single and double layers. The folded area was scanned with a high-resolution scanner while the samples were kept at their folded angle. The scanned images were analyzed within a constant area. The crack areas were reported for different types of papers, binder system and PVC values. As PVC, starch content, and paper basis weight increased, the crack area increased. Double layer coated papers with high PVC and high starch content at the top layer had more cracks in comparison with a single layer coated paper, but when the PVC of the top layer was low, cracking area decreased. No measurable cracking was observed when the top layer was formulated with a 100% latex layer.

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