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.

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.

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.

Asymptotics toward a nonlinear wave for an outflow problem of a model of viscous ions motion

2017 ◽  
Vol 27 (11) ◽  
pp. 2111-2145 ◽  
Author(s):  
Yeping Li ◽  
Peicheng Zhu
Keyword(s):  
Nonlinear Wave ◽  
The Self ◽  
Navier Stokes ◽  
Asymptotically Stable ◽  
Spatial Decay ◽  
Main Ingredient ◽  
One Dimensional ◽  
Poisson Equations ◽  
Self Consistent ◽  
The One

We shall investigate the asymptotic stability, toward a nonlinear wave, of the solution to an outflow problem for the one-dimensional compressible Navier–Stokes–Poisson equations. First, we construct this nonlinear wave which, under suitable assumptions, is the superposition of a stationary solution and a rarefaction wave. Then it is shown that the nonlinear wave is asymptotically stable in the case that the initial data are a suitably small perturbation of the nonlinear wave. The main ingredient of the proof is the [Formula: see text]-energy method that takes into account both the effect of the self-consistent electrostatic potential and the spatial decay of the stationary part of the nonlinear wave.

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.

Marginal stability and critical thickness of strong double layers

1981 ◽  
Vol 26 (2) ◽  
pp. 317-331 ◽  
Author(s):  
Christer Wahlberg
Keyword(s):  
Double Layer ◽  
Critical Thickness ◽  
Double Layers ◽  
Marginal Stability ◽  
Electron Configuration ◽  
The Stability

Previous investigations of the stability, in particular the critical thickness for marginal stability, of an electron configuration of double-layer type are extended in order to include effects of (i) unequal plasma densities in the field-free regions, and (ii) finite values of the parameter eΔø/kTe. The results obtained are compared with the corresponding quantities in various experiments, and a striking coincidence is found.

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.

scholarly journals A neural network closure for the Euler-Poisson system based on kinetic simulations

2021 ◽  
Vol 0 (0) ◽  
pp. 0
Author(s):  
Léo Bois ◽  
Emmanuel Franck ◽  
Laurent Navoret ◽  
Vincent Vigon
Keyword(s):  
Neural Network ◽  
Spatial Density ◽  
Data Generation ◽  
Poisson System ◽  
Mean Velocity ◽  
One Dimensional ◽  
Poisson Equations ◽  
Wide Range ◽  
The One ◽  
Uniform Accuracy

<p style='text-indent:20px;'>This work deals with the modeling of plasmas, which are ionized gases. Thanks to machine learning, we construct a closure for the one-dimensional Euler-Poisson system valid for a wide range of collisional regimes. This closure, based on a fully convolutional neural network called V-net, takes as input the whole spatial density, mean velocity and temperature and predicts as output the whole heat flux. It is learned from data coming from kinetic simulations of the Vlasov-Poisson equations. Data generation and preprocessings are designed to ensure an almost uniform accuracy over the chosen range of Knudsen numbers (which parametrize collisional regimes). Finally, several numerical tests are carried out to assess validity and flexibility of the whole pipeline.</p>

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.

Analytical Study of Supercritical Water Flow in Two Heated Parallel Channels With Wall Heat Effects

2018 ◽  
Author(s):  
Dhanashree S. Ghadge ◽  
Vijay Chatoorgoon
Keyword(s):  
Supercritical Water ◽  
Power Distribution ◽  
Analytical Study ◽  
Heat Storage ◽  
Stability Boundary ◽  
Numerical Results ◽  
One Dimensional ◽  
Heat Effects ◽  
The Stability ◽  
Frequency Domain Approach

One dimensional (1D) numerical simulations have been carried out of heated parallel channel experiments using the linear frequency domain approach to investigate the effect of wall heat on the system’s stability for supercritical water in vertical heated channels. Oscillatory instability boundaries of the experimental cases with two different wall thicknesses and uniform power distribution are produced, assessed and discussed. These new numerical results with wall heat are compared with experimental data and previous numerical results without wall heat. There is improved agreement on the stability boundary predictions when the wall heat storage effect is included. However, the effect of wall heat storage was small for these experiments.

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