WorldWideScience

Sample records for two-dimensional complex plasma

  1. Flame propagation in two-dimensional solids: Particle-resolved studies with complex plasmas

    Science.gov (United States)

    Yurchenko, S. O.; Yakovlev, E. V.; Couëdel, L.; Kryuchkov, N. P.; Lipaev, A. M.; Naumkin, V. N.; Kislov, A. Yu.; Ovcharov, P. V.; Zaytsev, K. I.; Vorob'ev, E. V.; Morfill, G. E.; Ivlev, A. V.

    2017-10-01

    Using two-dimensional (2D) complex plasmas as an experimental model system, particle-resolved studies of flame propagation in classical 2D solids are carried out. Combining experiments, theory, and molecular dynamics simulations, we demonstrate that the mode-coupling instability operating in 2D complex plasmas reveals all essential features of combustion, such as an activated heat release, two-zone structure of the self-similar temperature profile ("flame front"), as well as thermal expansion of the medium and temperature saturation behind the front. The presented results are of relevance for various fields ranging from combustion and thermochemistry, to chemical physics and synthesis of materials.

  2. Quasi-two-dimensional complex plasma containing spherical particles and their binary agglomerates.

    Science.gov (United States)

    Chaudhuri, M; Semenov, I; Nosenko, V; Thomas, H M

    2016-05-01

    A unique type of quasi-two-dimensional complex plasma system was observed which consisted of monodisperse microspheres and their binary agglomerations (dimers). The particles and their dimers levitated in a plasma sheath at slightly different heights and formed two distinct sublayers. The system did not crystallize and may be characterized as a disordered solid. The dimers were identified based on their characteristic appearance in defocused images, i.e., rotating interference fringe patterns. The in-plane and interplane particle separations exhibit nonmonotonic dependence on the discharge pressure.

  3. Generation of two-dimensional binary mixtures in complex plasmas

    Science.gov (United States)

    Wieben, Frank; Block, Dietmar

    2016-10-01

    Complex plasmas are an excellent model system for strong coupling phenomena. Under certain conditions the dust particles immersed into the plasma form crystals which can be analyzed in terms of structure and dynamics. Previous experiments focussed mostly on monodisperse particle systems whereas dusty plasmas in nature and technology are polydisperse. Thus, a first and important step towards experiments in polydisperse systems are binary mixtures. Recent experiments on binary mixtures under microgravity conditions observed a phase separation of particle species with different radii even for small size disparities. This contradicts several numerical studies of 2D binary mixtures. Therefore, dedicated experiments are required to gain more insight into the physics of polydisperse systems. In this contribution first ground based experiments on two-dimensional binary mixtures are presented. Particular attention is paid to the requirements for the generation of such systems which involve the consideration of the temporal evolution of the particle properties. Furthermore, the structure of these two-component crystals is analyzed and compared to simulations. This work was supported by the Deutsche Forschungsgemeinschaft DFG in the framework of the SFB TR24 Greifswald Kiel, Project A3b.

  4. Scale-free crystallization of two-dimensional complex plasmas: Domain analysis using Minkowski tensors

    Science.gov (United States)

    Böbel, A.; Knapek, C. A.; Räth, C.

    2018-05-01

    Experiments of the recrystallization processes in two-dimensional complex plasmas are analyzed to rigorously test a recently developed scale-free phase transition theory. The "fractal-domain-structure" (FDS) theory is based on the kinetic theory of Frenkel. It assumes the formation of homogeneous domains, separated by defect lines, during crystallization and a fractal relationship between domain area and boundary length. For the defect number fraction and system energy a scale-free power-law relation is predicted. The long-range scaling behavior of the bond-order correlation function shows clearly that the complex plasma phase transitions are not of the Kosterlitz, Thouless, Halperin, Nelson, and Young type. Previous preliminary results obtained by counting the number of dislocations and applying a bond-order metric for structural analysis are reproduced. These findings are supplemented by extending the use of the bond-order metric to measure the defect number fraction and furthermore applying state-of-the-art analysis methods, allowing a systematic testing of the FDS theory with unprecedented scrutiny: A morphological analysis of lattice structure is performed via Minkowski tensor methods. Minkowski tensors form a complete family of additive, motion covariant and continuous morphological measures that are sensitive to nonlinear properties. The FDS theory is rigorously confirmed and predictions of the theory are reproduced extremely well. The predicted scale-free power-law relation between defect fraction number and system energy is verified for one more order of magnitude at high energies compared to the inherently discontinuous bond-order metric. It is found that the fractal relation between crystalline domain area and circumference is independent of the experiment, the particular Minkowski tensor method, and the particular choice of parameters. Thus, the fractal relationship seems to be inherent to two-dimensional phase transitions in complex plasmas. Minkowski

  5. Full melting of a two-dimensional complex plasma crystal triggered by localized pulsed laser heating

    Science.gov (United States)

    Couëdel, L.; Nosenko, V.; Rubin-Zuzic, M.; Zhdanov, S.; Elskens, Y.; Hall, T.; Ivlev, A. V.

    2018-04-01

    The full melting of a two-dimensional plasma crystal was induced in a principally stable monolayer by localized laser stimulation. Two distinct behaviors of the crystal after laser stimulation were observed depending on the amount of injected energy: (i) below a well-defined threshold, the laser melted area recrystallized; (ii) above the threshold, it expanded outwards in a similar fashion to mode-coupling instability-induced melting, rapidly destroying the crystalline order of the whole complex plasma monolayer. The reported experimental observations are due to the fluid mode-coupling instability, which can pump energy into the particle monolayer at a rate surpassing the heat transport and damping rates in the energetic localized melted spot, resulting in its further growth. This behavior exhibits remarkable similarities with impulsive spot heating in ordinary reactive matter.

  6. Two-dimensional heat conducting simulation of plasma armatures

    International Nuclear Information System (INIS)

    Huerta, M.A.; Boynton, G.

    1991-01-01

    This paper reports on our development of a two-dimensional MHD code to simulate internal motions in a railgun plasma armature. The authors use the equations of resistive MHD, with Ohmic heating, and radiation heat transport. The authors use a Flux Corrected Transport code to advance all quantities in time. Our runs show the development of complex flows, subsequent shedding of secondary arcs, and a drop in the acceleration of the armature

  7. Two-dimensional Simulations of Correlation Reflectometry in Fusion Plasmas

    International Nuclear Information System (INIS)

    Valeo, E.J.; Kramer, G.J.; Nazikian, R.

    2001-01-01

    A two-dimensional wave propagation code, developed specifically to simulate correlation reflectometry in large-scale fusion plasmas is described. The code makes use of separate computational methods in the vacuum, underdense and reflection regions of the plasma in order to obtain the high computational efficiency necessary for correlation analysis. Simulations of Tokamak Fusion Test Reactor (TFTR) plasma with internal transport barriers are presented and compared with one-dimensional full-wave simulations. It is shown that the two-dimensional simulations are remarkably similar to the results of the one-dimensional full-wave analysis for a wide range of turbulent correlation lengths. Implications for the interpretation of correlation reflectometer measurements in fusion plasma are discussed

  8. Two-dimensional transport of tokamak plasmas

    International Nuclear Information System (INIS)

    Hirshman, S.P.; Jardin, S.C.

    1979-01-01

    A reduced set of two-fluid transport equations is obtained from the conservation equations describing the time evolution of the differential particle number, entropy, and magnetic fluxes in an axisymmetric toroidal plasma with nested magnetic surfaces. Expanding in the small ratio of perpendicular to parallel mobilities and thermal conductivities yields as solubility constraints one-dimensional equations for the surface-averaged thermodynamic variables and magnetic fluxes. Since Ohm's law E +u x B =R', where R' accounts for any nonideal effects, only determines the particle flow relative to the diffusing magnetic surfaces, it is necessary to solve a single two-dimensional generalized differential equation, (partial/partialt) delpsi. (delp - J x B) =0, to find the absolute velocity of a magnetic surface enclosing a fixed toroidal flux. This equation is linear but nonstandard in that it involves flux surface averages of the unknown velocity. Specification of R' and the cross-field ion and electron heat fluxes provides a closed system of equations. A time-dependent coordinate transformation is used to describe the diffusion of plasma quantities through magnetic surfaces of changing shape

  9. Complex dynamical invariants for two-dimensional complex potentials

    Indian Academy of Sciences (India)

    Abstract. Complex dynamical invariants are searched out for two-dimensional complex poten- tials using rationalization method within the framework of an extended complex phase space characterized by x = x1 + ip3, y = x2 + ip4, px = p1 + ix3, py = p2 + ix4. It is found that the cubic oscillator and shifted harmonic oscillator ...

  10. Two-dimensional model of a freely expanding plasma

    International Nuclear Information System (INIS)

    Khalid, Q.

    1975-01-01

    The free expansion of an initially confined plasma is studied by the computer experiment technique. The research is an extension to two dimensions of earlier work on the free expansion of a collisionless plasma in one dimension. In the two-dimensional rod model, developed in this research, the plasma particles, electrons and ions are modeled as infinitely long line charges or rods. The line charges move freely in two dimensions normal to their parallel axes, subject only to a self-consistent electric field. Two approximations, the grid approximation and the periodic boundary condition are made in order to reduce the computation time. In the grid approximation, the space occupied by the plasma at a given time is divided into boxes. The particles are subject to an average electric field calculated for that box assuming that the total charge within each box is located at the center of the box. However, the motion of each particle is exactly followed. The periodic boundary condition allows us to consider only one-fourth of the total number of particles of the plasma, representing the remaining three-fourths of the particles as symmetrically placed images of those whose positions are calculated. This approximation follows from the expected azimuthal symmetry of the plasma. The dynamics of the expansion are analyzed in terms of average ion and electron positions, average velocities, oscillation frequencies and relative distribution of energy between thermal, flow and electric field energies. Comparison is made with previous calculations of one-dimensional models which employed plane, spherical or cylindrical sheets as charged particles. In order to analyze the effect of the grid approximation, the model is solved for two different grid sizes and for each grid size the plasma dynamics is determined. For the initial phase of expansion, the agreement for the two grid sizes is found to be good

  11. Fractional calculus phenomenology in two-dimensional plasma models

    Science.gov (United States)

    Gustafson, Kyle; Del Castillo Negrete, Diego; Dorland, Bill

    2006-10-01

    Transport processes in confined plasmas for fusion experiments, such as ITER, are not well-understood at the basic level of fully nonlinear, three-dimensional kinetic physics. Turbulent transport is invoked to describe the observed levels in tokamaks, which are orders of magnitude greater than the theoretical predictions. Recent results show the ability of a non-diffusive transport model to describe numerical observations of turbulent transport. For example, resistive MHD modeling of tracer particle transport in pressure-gradient driven turbulence for a three-dimensional plasma reveals that the superdiffusive (2̂˜t^α where α> 1) radial transport in this system is described quantitatively by a fractional diffusion equation Fractional calculus is a generalization involving integro-differential operators, which naturally describe non-local behaviors. Our previous work showed the quantitative agreement of special fractional diffusion equation solutions with numerical tracer particle flows in time-dependent linearized dynamics of the Hasegawa-Mima equation (for poloidal transport in a two-dimensional cold-ion plasma). In pursuit of a fractional diffusion model for transport in a gyrokinetic plasma, we now present numerical results from tracer particle transport in the nonlinear Hasegawa-Mima equation and a planar gyrokinetic model. Finite Larmor radius effects will be discussed. D. del Castillo Negrete, et al, Phys. Rev. Lett. 94, 065003 (2005).

  12. Magnetic dipolar interaction in two-dimensional complex plasmas

    International Nuclear Information System (INIS)

    Feldmann, J D; Kalman, G J; Rosenberg, M

    2006-01-01

    Various interactions can play a role between the mesoscopic dust grains of a complex plasma. We study a system composed of dust grains that have both an electric charge and a permanent magnetic dipole moment. It is assumed that the grains occupy lattice sites, as dictated by their Coulomb interaction. In addition, they possess a spin degree of freedom (orientation of magnetic dipole moment) that is not constrained by the Coulomb interaction, thus allowing for the possibility of equilibrium orientational ordering and 'wobbling' about the equilibrium orientations. As a result, collective modes develop. We identify in-plane and out-of-plane wobbling modes and discuss their dispersion characteristics both in the ferromagnetic and in the anti-ferromagnetic ground state

  13. An energy principle for two-dimensional collisionless relativistic plasmas

    International Nuclear Information System (INIS)

    Otto, A.; Schindler, K.

    1984-01-01

    Using relativistic Vlasov theory an energy principle for two-dimensional plasmas is derived, which provides a sufficient and necessary criterion for the stability of relativistic plasma equilibria. This energy principle includes charge separating effects since the exact Poisson equation was taken into consideration. Applying the variational principle to the case of the relativistic plane plasma sheet, the same marginal wave length is found as in the non-relativistic case. (author)

  14. Two-Dimensional One-Component Plasma on Flamm's Paraboloid

    Science.gov (United States)

    Fantoni, Riccardo; Téllez, Gabriel

    2008-11-01

    We study the classical non-relativistic two-dimensional one-component plasma at Coulomb coupling Γ=2 on the Riemannian surface known as Flamm's paraboloid which is obtained from the spatial part of the Schwarzschild metric. At this special value of the coupling constant, the statistical mechanics of the system are exactly solvable analytically. The Helmholtz free energy asymptotic expansion for the large system has been found. The density of the plasma, in the thermodynamic limit, has been carefully studied in various situations.

  15. Level crossings in complex two-dimensional potentials

    Indian Academy of Sciences (India)

    Two-dimensional P T -symmetric quantum-mechanical systems with the complex cubic potential 12 = 2 + 2 + 2 and the complex Hénon–Heiles potential HH = 2 + 2 + (2 − 3/3) are investigated. Using numerical and perturbative methods, energy spectra are obtained to high levels. Although both ...

  16. Crystallization process of a three-dimensional complex plasma

    Science.gov (United States)

    Steinmüller, Benjamin; Dietz, Christopher; Kretschmer, Michael; Thoma, Markus H.

    2018-05-01

    Characteristic timescales and length scales for phase transitions of real materials are in ranges where a direct visualization is unfeasible. Therefore, model systems can be useful. Here, the crystallization process of a three-dimensional complex plasma under gravity conditions is considered where the system ranges up to a large extent into the bulk plasma. Time-resolved measurements exhibit the process down to a single-particle level. Primary clusters, consisting of particles in the solid state, grow vertically and, secondarily, horizontally. The box-counting method shows a fractal dimension of df≈2.72 for the clusters. This value gives a hint that the formation process is a combination of local epitaxial and diffusion-limited growth. The particle density and the interparticle distance to the nearest neighbor remain constant within the clusters during crystallization. All results are in good agreement with former observations of a single-particle layer.

  17. Two-dimensional plasma photonic crystals in dielectric barrier discharge

    International Nuclear Information System (INIS)

    Fan Weili; Dong Lifang; Zhang Xinchun

    2010-01-01

    A series of two-dimensional plasma photonic crystals have been obtained by filaments' self-organization in atmospheric dielectric barrier discharge with two water electrodes, which undergo the transition from square to square superlattice and finally to the hexagon. The spatio-temporal behaviors of the plasma photonic crystals in nanosecond scale have been studied by optical method, which show that the plasma photonic crystal is actually an integration of different transient sublattices. The photonic band diagrams of the transverse electric (TE) mode and transverse magnetic mode for each sublattice of these plasma photonic crystals have been investigated theoretically. A wide complete band gap is formed in the hexagonal plasma photonic crystal with the TE mode. The changes of the band edge frequencies and the band gap widths in the evolvement of different structures are studied. A kind of tunable plasma photonic crystal which can be controlled both in space and time is suggested.

  18. Two dimensional kinetic analysis of electrostatic harmonic plasma waves

    Energy Technology Data Exchange (ETDEWEB)

    Fonseca-Pongutá, E. C.; Ziebell, L. F.; Gaelzer, R. [Instituto de Física, UFRGS, 91501-970 Porto Alegre, RS (Brazil); Yoon, P. H. [IPST, University of Maryland, College Park, Maryland 20742 (United States); SSR, Kyung Hee University, Yongin, Gyeonggi 446-701 (Korea, Republic of)

    2016-06-15

    Electrostatic harmonic Langmuir waves are virtual modes excited in weakly turbulent plasmas, first observed in early laboratory beam-plasma experiments as well as in rocket-borne active experiments in space. However, their unequivocal presence was confirmed through computer simulated experiments and subsequently theoretically explained. The peculiarity of harmonic Langmuir waves is that while their existence requires nonlinear response, their excitation mechanism and subsequent early time evolution are governed by essentially linear process. One of the unresolved theoretical issues regards the role of nonlinear wave-particle interaction process over longer evolution time period. Another outstanding issue is that existing theories for these modes are limited to one-dimensional space. The present paper carries out two dimensional theoretical analysis of fundamental and (first) harmonic Langmuir waves for the first time. The result shows that harmonic Langmuir wave is essentially governed by (quasi)linear process and that nonlinear wave-particle interaction plays no significant role in the time evolution of the wave spectrum. The numerical solutions of the two-dimensional wave spectra for fundamental and harmonic Langmuir waves are also found to be consistent with those obtained by direct particle-in-cell simulation method reported in the literature.

  19. On melting criteria for complex plasma

    International Nuclear Information System (INIS)

    Klumov, Boris A

    2011-01-01

    The present paper considers melting criteria for a plasma crystal discovered in dust plasma in 1994. Separate discussions are devoted to three-dimensional (3D) and two-dimensional (2D) systems. In the 3D case, melting criteria are derived based on the properties of local order in a system of microparticles. The order parameters are constructed from the cumulative distributions of the microparticle probability distributions as functions of various rotational invariants. The melting criteria proposed are constructed using static information on microparticle positions: a few snapshots of the system that allow for the determination of particle coordinates are enough to determine the phase state of the system. It is shown that criteria obtained in this way describe well the melting and premelting of 3D complex plasmas. In 2D systems, a system of microparticles interacting via a screened Coulomb (i.e., Debye-Hueckel or Yukawa) potential is considered as an example, using molecular dynamics simulations. A number of new order parameters characterizing the melting of 2D complex plasmas are proposed. The order parameters and melting criteria proposed for 2D and 3D complex plasmas can be applied to other systems as well. (methodological notes)

  20. Particle simulation of a two-dimensional electrostatic plasma

    International Nuclear Information System (INIS)

    Patel, K.

    1989-01-01

    Computer simulation is a growing field of research and plasma physics is one of the important areas where it is being applied today. This report describes the particle method of simulating a two-dimensional electrostatic plasma. The methods used to discretise the plasma equations and integrate the equations of motion are outlined. The algorithm used in building a simulation program is described. The program is applied to simulating the Two-stream Instability occurring within an infinite plasma. The results of the simulation are presented. The growth rate of the instability as simulated is in excellent agreement with the growth rate as calculated using linear theory. Diagnostic techniques used in interpreting the data generated by the simulation program are discussed. A comparison of the computing environment of the ND and PC from a user's viewpoint is presented. It is observed that the PC is an acceptable computing tool for certain (non-trivial) physics problems, and that more extensive use of its computing power should be made. (author). 5 figs

  1. Consistent two-dimensional visualization of protein-ligand complex series

    Directory of Open Access Journals (Sweden)

    Stierand Katrin

    2011-06-01

    Full Text Available Abstract Background The comparative two-dimensional graphical representation of protein-ligand complex series featuring different ligands bound to the same active site offers a quick insight in their binding mode differences. In comparison to arbitrary orientations of the residue molecules in the individual complex depictions a consistent placement improves the legibility and comparability within the series. The automatic generation of such consistent layouts offers the possibility to apply it to large data sets originating from computer-aided drug design methods. Results We developed a new approach, which automatically generates a consistent layout of interacting residues for a given series of complexes. Based on the structural three-dimensional input information, a global two-dimensional layout for all residues of the complex ensemble is computed. The algorithm incorporates the three-dimensional adjacencies of the active site residues in order to find an universally valid circular arrangement of the residues around the ligand. Subsequent to a two-dimensional ligand superimposition step, a global placement for each residue is derived from the set of already placed ligands. The method generates high-quality layouts, showing mostly overlap-free solutions with molecules which are displayed as structure diagrams providing interaction information in atomic detail. Application examples document an improved legibility compared to series of diagrams whose layouts are calculated independently from each other. Conclusions The presented method extends the field of complex series visualizations. A series of molecules binding to the same protein active site is drawn in a graphically consistent way. Compared to existing approaches these drawings substantially simplify the visual analysis of large compound series.

  2. Kubo conductivity of a strongly magnetized two-dimensional plasma.

    Science.gov (United States)

    Montgomery, D.; Tappert, F.

    1971-01-01

    The Kubo formula is used to evaluate the bulk electrical conductivity of a two-dimensional guiding-center plasma in a strong dc magnetic field. The particles interact only electrostatically. An ?anomalous' electrical conductivity is derived for this system, which parallels a recent result of Taylor and McNamara for the coefficient of spatial diffusion.

  3. Development of a Two-Dimensional Tracker with Plasma Panel Detector

    CERN Document Server

    AUTHOR|(CDS)2233132

    Plasma panel sensors are micropattern gaseous radiation detectors which are based on the technology of plasma display panels. This thesis summarizes the research that had been done on commercially available plasma display panels that were converted to plasma panel sensor prototypes and describes the construction of a two-dimensional tracker consisting of four of those prototypes, with one-dimensional readout on each, used to detect tracks of cosmic muons. A large amount of 2-point as well as 3 and 4-point tracks were detected. Qualitative analyses as well as Pearson’s χ2 tests are performed on the track angular distribution and on a histogram of the linearity measure of 3-point tracks to reject the hypothesis that these tracks result from completely random panel hits. Some RF noise effects contributing to false positives are ruled out, while it is shown that other effects can be ruled out only with a high-intensity minimum ionizing particle source. A significant part of the tracker construction was the dev...

  4. Two dimensional neutral transport analysis in tokamak plasma

    International Nuclear Information System (INIS)

    Shimizu, Katsuhiro; Azumi, Masafumi

    1987-02-01

    Neutral particle influences the particle and energy balance, and play an important role on sputtering impurity and the charge exchange loss of neutral beam injection. In order to study neutral particle behaviour including the effects of asymmetric source and divertor configuration, the two dimensional neutral transport code has been developed using the Monte-Carlo techniques. This code includes the calculation of the H α radiation intensity based on the collisional-radiation model. The particle confinement time of the joule heated plasma in JT-60 tokamak is evaluated by comparing the calculated H α radiation intensity with the experimental data. The effect of the equilibrium on the neutral density profile in high-β plasma is also investigated. (author)

  5. Two and three dimensional imaging of compact toroid plasmas using fast photography

    International Nuclear Information System (INIS)

    Englert, S.E.; Bell, D.E.; Coffey, S.K.

    1992-01-01

    As is discussed in a companion paper, Degnan el al, fast photography is used as a visual diagnostic tool for high energy plasma research at the Phillips Laboratory. Both, two dimensional and three dimensional images, are gathered by using nanosecond and microsecond range fast photography techniques. A set of microchannel plate cameras and a fast framing camera are used to record images of a compact toroid plasma during formation and acceleration stages. These images are subsequently digitized and enhanced to bring out detailed information of interest. This spatial information is combined with other diagnostic results as well as theoretical models in order to build a more complete picture of the fundamental physics associated with high-energy plasmas

  6. Two-dimensional nanoparticle self-assembly using plasma-induced Ostwald ripening

    International Nuclear Information System (INIS)

    Tang, J; Photopoulos, P; Tsoukalas, D; Tserepi, A

    2011-01-01

    In this work, a novel Ag nanoparticle self-assembly process based on plasma-induced two-dimensional Ostwald ripening is demonstrated. Ag nanoparticles are deposited on p-doped Si substrates using a DC magnetron sputtering process. With the assistance of O 2 /Ar plasma treatment, different sizes and patterns of Ag nanoparticles are formed, due to the Ostwald ripening. The evolution of plasma-induced nanoparticle ripening is studied and a clear increase in particle size and a decrease in particle density are observed with increasing plasma treatment. From the experiments, it is concluded that the initial nanoparticle density and the plasma gas mixture (Ar/O 2 ratio) are important factors that affect the ripening process. The proposed plasma-directed Ag nanoparticle self-assembly provides a rapid method of tailoring the nanoparticle distribution on substrates, with potential applications in the fields of solar cells, biosensors, and catalysis.

  7. Two-dimensional electron flow in pulsed power transmission lines and plasma opening switches

    International Nuclear Information System (INIS)

    Church, B.W.; Longcope, D.W.; Ng, C.K.; Sudan, R.N.

    1991-01-01

    The operation of magnetically insulated transmission lines (MITL) and the interruption of current in a plasma opening switch (POS) are determined by the physics of the electrons emitted by the cathode surface. A mathematical model describes the self-consistent two-dimensional flow of an electron fluid. A finite element code, FERUS, has been developed to solve the two equations which describe Poisson's and Ampere's law in two dimensions. The solutions from this code are obtained for parameters where the electron orbits are considerably modified by the self-magnetic field of the current. Next, the self-insulated electron flow in a MITL with a step change in cross-section is studied using a conventional two-dimensional fully electromagnetic particle-in-cell code, MASK. The equations governing two-dimensional quasi-static electron flow are solved numerically by a third technique which is suitable for predicting current interruption in a POS. The object of the study is to determine the critical load impedance, Z CL , required for current interruption for a given applied voltage, cathode voltage and plasma length. (author). 9 refs, 5 figs

  8. Dispersion characteristics of two-dimensional unmagnetized dielectric plasma photonic crystal

    International Nuclear Information System (INIS)

    Li-Mei, Qi; Zi-Qiang, Yang; Feng, Lan; Xi, Gao; Da-Zhi, Li

    2010-01-01

    This paper studies dispersion characteristics of the transverse magnetic (TM) mode for two-dimensional unmagnetized dielectric plasma photonic crystal by a modified plane wave method. First, the cutoff behaviour is made clear by using the Maxwell–Garnett effective medium theory, and the influences of dielectric filling factor and dielectric constant on effective plasma frequency are analysed. Moreover, the occurence of large gaps in dielectric plasma photonic crystal is demonstrated by comparing the skin depth with the lattice constant, and the influence of plasma frequency on the first three gaps is also studied. Finally, by using the particle-in-cell simulation method, a transmission curve in the Γ – X direction is obtained in dielectric plasma photonic crystal, which is in accordance with the dispersion curves calculated by the modified plane wave method, and the large gap between the transmission points of 27 GHz and 47 GHz is explained by comparing the electric field patterns in particle-in-cell simulation

  9. Approximate solutions for the two-dimensional integral transport equation. Solution of complex two-dimensional transport problems

    International Nuclear Information System (INIS)

    Sanchez, Richard.

    1980-11-01

    This work is divided into two parts: the first part deals with the solution of complex two-dimensional transport problems, the second one (note CEA-N-2166) treats the critically mixed methods of resolution. A set of approximate solutions for the isotropic two-dimensional neutron transport problem has been developed using the interface current formalism. The method has been applied to regular lattices of rectangular cells containing a fuel pin, cladding, and water, or homogenized structural material. The cells are divided into zones that are homogeneous. A zone-wise flux expansion is used to formulate a direct collision probability problem within a cell. The coupling of the cells is effected by making extra assumptions on the currents entering and leaving the interfaces. Two codes have been written: CALLIOPE uses a cylindrical cell model and one or three terms for the flux expansion, and NAUSICAA uses a two-dimensional flux representation and does a truly two-dimensional calculation inside each cell. In both codes, one or three terms can be used to make a space-independent expansion of the angular fluxes entering and leaving each side of the cell. The accuracies and computing times achieved with the different approximations are illustrated by numerical studies on two benchmark problems and by calculations performed in the APOLLO multigroup code [fr

  10. Photon-exchange energy transfer of an electron–hole plasma between quasi-two-dimensional semiconductor layers

    International Nuclear Information System (INIS)

    Lyo, S.K.

    2012-01-01

    Photon-mediated energy transfer is shown to play an important role for transfer of an electron–hole plasma between two quasi-two-dimensional quantum wells separated by a wide barrier. The magnitude and the dependence of the transfer rate of an electron–hole plasma on the temperature, the well-to-well distance, and the plasma density are compared with those of the standard Förster (i.e., dipolar) rate and also with the exciton transfer rate. The plasma transfer rate through the photon-exchange mechanism decays very slowly as a function of the well-to-well distance and is larger than the dipolar rate except for short distances. The transfer rate of plasmas saturates at high densities and decays rapidly with the temperature. - Highlights: ► We study energy transfer (ET) between two two-dimensional semiconductor quantum wells. ► We compare the ET rates of an electron–hole plasma (at a high density) and Mott excitons. ► We show that the proposed photon-exchange rate is practically dominant over the Förster rate. ► We examine the dependences of the ET rate on the temperature, density, and well-to-well distance.

  11. Two-dimensional analysis of limiter/divertor transition in scrape-off layer plasmas

    International Nuclear Information System (INIS)

    Ueda, N.; Itoh, K.; Itoh, S.I.

    1989-01-01

    The structures of scrape-off layer and divertor plasmas have been studied numerically with a neutral code and a two-dimensional fluid code. Doublet-III is taken as an example for an open divertor configuration. A decisive parameter is the distance between the plasma surface (determined by the magnetic separatrix) and the limiter, which is varied in order to assess the interaction of the plasma with the limiter as well as the effect of neutrals on the main plasma. The minimum value of the limiter clearance needed to prevent plasma-limiter interaction is determined. The scaling of the edge temperature and the dependence of the e-folding length of the scrape-off layer plasma on the heating power are obtained. (author). 16 refs, 17 figs

  12. Equatorial spread F studies using SAMI3 with two-dimensional and three-dimensional electrostatics

    Directory of Open Access Journals (Sweden)

    H. C. Aveiro

    2013-12-01

    Full Text Available This letter presents a study of equatorial F region irregularities using the NRL SAMI3/ESF model, comparing results using a two-dimensional (2-D and a three-dimensional (3-D electrostatic potential solution. For the 3-D potential solution, two cases are considered for parallel plasma transport: (1 transport based on the parallel ambipolar field, and (2 transport based on the parallel electric field. The results show that the growth rate of the generalized Rayleigh–Taylor instability is not affected by the choice of the potential solution. However, differences are observed in the structures of the irregularities between the 2-D and 3-D solutions. Additionally, the plasma velocity along the geomagnetic field computed using the full 3-D solution shows complex structures that are not captured by the simplified model. This points out that only the full 3-D model is able to fully capture the complex physics of the equatorial F region.

  13. Two-dimensional hydrodynamics of uniform ion plasma in electrostatic field

    International Nuclear Information System (INIS)

    Mahdieh, M. H.; Gavili, A.

    2005-01-01

    Two-dimensional hydrodynamics of ion extraction from uniform quasi-neutral plasma, in electrostatic field has been simulated numerically. Experimentally, tunable pulsed lasers produce non-uniform plasma through stepwise photo-excitation and photo-ionization or multi-photo-ionization processes. Poisson's equation was solved simultaneously with the equations of mass, and momentum, assuming the Maxwell-Boltzmann distribution for electrons. In the calculation, the initial density profile at the boundaries has been assumed to be very steep for the ion plasma. In these calculations dynamics of electric potential and the ions density were assessed. The ion extraction time was also estimated from the calculation. The knowledge of spatial distribution of the ions across the cathode is very important for the practical purposes. In this simulation, the spatial distribution of the ion current density across the cathode as well as its temporal distribution was calculated

  14. Three dimensional complex plasma structures in a combined radio frequency and direct current discharge

    International Nuclear Information System (INIS)

    Mitic, S.; Morfill, G. E.; Klumov, B. A.; Khrapak, S. A.

    2013-01-01

    We report on the first detailed analysis of large three dimensional (3D) complex plasma structures in experiments performed in pure rf and combined rf+dc discharge modes. Inductively coupled plasma is generated by an rf coil wrapped around the vertically positioned cylindrical glass tube at a pressure of 0.3 mbar. In addition, dc plasma can be generated by applying voltage to the electrodes at the ends of the tube far from the rf coil. The injected monodisperse particles are levitated in the plasma below the coil. A scanning laser sheet and a high resolution camera are used to determine the 3D positions of about 10 5 particles. The observed bowl-shaped particle clouds reveal coexistence of various structures, including well-distinguished solid-like, less ordered liquid-like, and pronounced string-like phases. New criteria to identify string-like structures are proposed.

  15. Two-dimensional NMR studies of allyl palladium complexes of ...

    Indian Academy of Sciences (India)

    Administrator

    h3-Allyl complexes are intermediates in organic synthetic reactions such as allylic alkylation and amination. There is growing interest in understanding the structures of chiral h3-allyl intermediates as this would help to unravel the mechanism of enantioselective C–C bond forming reactions. Two-dimensional NMR study is a.

  16. Solution of Schroedinger Equation for Two-Dimensional Complex Quartic Potentials

    International Nuclear Information System (INIS)

    Singh, Ram Mehar; Chand, Fakir; Mishra, S. C.

    2009-01-01

    We investigate the quasi-exact solutions of the Schroedinger wave equation for two-dimensional non-hermitian complex Hamiltonian systems within the frame work of an extended complex phase space characterized by x = x 1 + ip 3 , y = x 2 + ip 4 , p x = p 1 + ix 3 , p y = p 2 + ix 4 . Explicit expressions of the energy eigenvalues and the eigenfunctions for ground and first excited states for a complex quartic potential are obtained. Eigenvalue spectra of some variants of the complex quartic potential, including PT-symmetric one, are also worked out. (general)

  17. Two-dimensional magnetohydrodynamic calculations for a 5 MJ plasma focus

    International Nuclear Information System (INIS)

    Maxon, S.

    1979-01-01

    The performance of a 5 MJ plasma focus is calculated using our two-dimensional magnetohydrodynamic (2-D MHD) code. Two configurations are discussed, a solid and a hollow anode. In the case of the hollow anode, we find an instability in the current sheath which has the characteristics of the short wave length sausage instability. As the current sheath reaches the axis, the numerical solution is seen to break down. Just before this time, plasma parameters take on the characteristic values rho/rho 0 = 143, kT/sup i/ = 7.4 keV, B/sub theta/ = 4.7 MG, and V/sub z/ = 60 cm/μs for a zone with r = 0.2 mm. When the numerical solution breaks down, the code shows a splitting of the current sheath (from the axis to the anode) and the loss of a large amount of magnetic energy. Current-sheath stagnation is observed in the hollow anode configuration, also

  18. Two-dimensional simulations of multi-hollow VHF SiH4/H2 plasma

    Directory of Open Access Journals (Sweden)

    Li-Wen Su

    2018-02-01

    Full Text Available A triode multi-hollow VHF SiH4/H2 plasma (60 MHz was examined at a pressure of 20 Pa by two-dimensional simulations using the fluid model. In this study, we considered the effect of the rate constant of reaction, SiH3 + SiH3→SiH2 + SiH4, on the plasma characteristics. A typical VHF plasma of a high-electron density with a low-electron temperature was obtained between two discharge electrodes. Spatial profiles of SiH3+, SiH2+, SiH3- and SiH3 densities were similar to that of the electron density while the electron temperature had a maximum value near the two discharge electrodes. It was found that the SiH3 radical density did not decrease rapidly near the substrate and the electron temperature was lower than 1 eV, suggesting that the triode multi-hollow plasma source can provide high quality amorphous silicon with a high deposition rate.

  19. Chaos in a complex plasma

    International Nuclear Information System (INIS)

    Sheridan, T.E.

    2005-01-01

    Chaotic dynamics is observed experimentally in a complex (dusty) plasma of three particles. A low-frequency sinusoidal modulation of the plasma density excites both the center-of-mass and breathing modes. Low-dimensional chaos is seen for a 1:2 resonance between these modes. A strange attractor with a dimension of 2.48±0.05 is observed. The largest Lyapunov exponent is positive

  20. Two-dimensional magnetohydrodynamic calculations for a 5 MJ plasma focus

    International Nuclear Information System (INIS)

    Maxon, S.

    1983-01-01

    This article describes the calculation of the performance of a 5 MJ plasma focus using a two-dimensional magnetohydrodynamic (2-D MHD) code. Discusses two configurations, a solid and a hollow anode. Finds an instability in the current sheath of the hollow anode which has the characteristics of the short wave length sausage instability. As the current sheath reaches the axis, the numerical solution is seen to break down. When the numerical solution breaks down, the code shows a splitting of the current sheath (from the axis to the anode) and the loss of a large amount of magnetic energy. Current-sheath stagnation is observed in the hollow anode configuration

  1. Ideal gas behavior of a strongly coupled complex (dusty) plasma.

    Science.gov (United States)

    Oxtoby, Neil P; Griffith, Elias J; Durniak, Céline; Ralph, Jason F; Samsonov, Dmitry

    2013-07-05

    In a laboratory, a two-dimensional complex (dusty) plasma consists of a low-density ionized gas containing a confined suspension of Yukawa-coupled plastic microspheres. For an initial crystal-like form, we report ideal gas behavior in this strongly coupled system during shock-wave experiments. This evidence supports the use of the ideal gas law as the equation of state for soft crystals such as those formed by dusty plasmas.

  2. Ideal gas behavior of a strongly-coupled complex (dusty) plasma

    OpenAIRE

    Oxtoby, Neil P.; Griffith, Elias J.; Durniak, Céline; Ralph, Jason F.; Samsonov, Dmitry

    2012-01-01

    In a laboratory, a two-dimensional complex (dusty) plasma consists of a low-density ionized gas containing a confined suspension of Yukawa-coupled plastic microspheres. For an initial crystal-like form, we report ideal gas behavior in this strongly-coupled system during shock-wave experiments. This evidence supports the use of the ideal gas law as the equation of state for soft crystals such as those formed by dusty plasmas.

  3. Two-body similarity and its violation in tokamak edge plasmas

    International Nuclear Information System (INIS)

    Catto, P.J.; Knoll, D.A.; Krasheninnikov, S.I.

    1996-01-01

    Scaling laws found under the assumption that two-body collisions dominate can be effectively used to benchmark complex multi-dimensional codes dedicated to investigating tokamak edge plasmas. The applicability of such scaling laws to the interpretation of experimental data, however, is found to be restricted to the relatively low plasma densities ( 19 m -3 ) at which multistep processes, which break the two-body collision approximation, are unimportant. copyright 1996 American Institute of Physics

  4. Oscillations of the positive column plasma due to ionization wave propagation and two-dimensional structure of striations

    International Nuclear Information System (INIS)

    Golubovskii, Yu B; Kozakov, R V; Wilke, C; Behnke, J; Nekutchaev, V O

    2004-01-01

    Time and space resolved measurements of the plasma potential in axial and radial directions in S- and P-striations in neon are performed. The measurements in different radial positions were carried out with high spatial resolution by means of simultaneous displacement of electrodes relative to the stationary probe. The plasma potential was found to be a superposition of the potentials of ionization wave and plasma oscillations relative to the electrodes. A method of decomposition of the measured spatio-temporal structure of the potential in components associated with the plasma oscillations and ionization wave propagation is proposed. A biorthogonal decomposition of the spatio-temporal structure of the potential is performed. A comparison of the decomposition results obtained by the two methods is made. The experiments revealed a two-dimensional structure of the potential field in an ionization wave. Qualitative discussions of the reasons for the occurrence of this two-dimensional structure are presented based on the analysis of the kinetic equation and the equation for the potential

  5. Two-dimensional simulation of the hydromagnetic Rayleigh-Taylor instability in an imploding foil plasma

    International Nuclear Information System (INIS)

    Roderick, N.F.; Hussey, T.W.; Faehl, R.J.; Boyd, R.W.

    1978-01-01

    Two-dimensional (r-z) magnetohydrodynamic simulations of the electromagnetic implosion of metallic foil plasmas show, for certain initial configurations, a tendency to develop large-amplitude perturbations characteristic of the hydromagnetic Rayleigh-Taylor instability. These perturbations develop at the plasma magnetic field interface for plasma configurations where the density gradient scale length, the characteristic dimension for the instability, is short. The effects on the plasma dynamics of the implosion will be discussed for several initial foil configurations. In general, the growth rates and linear mode structure are found to be influenced by the plasma shell thickness and density gradient scale length, in agreement with theory. The most destructive modes are found to be those with wavelengths of the order of the plasma shell thickness

  6. Two-dimensional single fluid MHD simulations of plasma opening switches

    International Nuclear Information System (INIS)

    Roderick, N.F.; Payne, S.S.; Peterkin, R.E. Jr.; Frese, M.H.; Hussey, T.W.

    1989-01-01

    Simulations of plasma opening switch have been made using two-dimensional, single fluid, magnetohydrodynamic codes HAM and MACH2. A variety of mechanisms for magnetic field penetration have been investigated. These include plasma convection, classical and microturbulent resistive diffusion, and Hall effect transport. We find that plasma microturbulent models are necessary to explain the broad current channels observed in experiments. Both heuristic and consistent microturbulent models are able to explain observed channel widths and penetration features. The best results are obtained for a consistent model that includes the Buneman, ion acoustic, and lower hybrid microturbulent collision frequencies and threshold conditions. Maximum microturbulent collision frequencies of 5 ω p , are typical. Field transport and current channel profiles are in excellent agreement with experimental observations for GAMBLE I, GAMBLE II, and SUPERMITE experiments. Dominant field penetration mechanisms and center of mass plasma motion are current and density dependent. Including the Hall effect enhanced field penetration. Center of mass motion is negligible for the GAMBLE I experiments but significant for the GAMBLE II conditions. Scaling of plasma opening time with switch length and density can be fit by linear representations for lengths from 0.03 m to 0.24 m and ion densities from 10 18 m -3 to 1.5 times 10 19 m -3 . 15 refs., 7 figs., 1 tab

  7. Three-dimensional analysis of nonlinear plasma oscillation

    International Nuclear Information System (INIS)

    Miano, G.

    1990-01-01

    In an underdense plasma a large-amplitude plasma oscillation may be produced by the beating of two external and colinear electromagnetic waves with a frequency difference approximately equal to the plasma frequency - plasma beat wave (PBW) resonant mechanism. The plasma oscillations are driven by the ponderomotive force arising from the beating of the two imposed electromagnetic waves. In this paper two pump electromagnetic waves with arbitrary transverse profiles have been considered. The plasma is described by using the three dimensinal weakly relativistic fluid equations. The nonlinear plasma oscillation dynamics is studied by using the eulerian description, the averaging and the multiple time scale methods. Unlike the linear theory a strong cross field coupling between longitudinal ans transverse electric field components of the plasma oscillation comes out, resulting in a nonlinear phase change and energy transfer between the two components. Unlike the one-dimensional nonlinear theory, the nonlinear frequency shift is caused by relativistic effects as well as by convective effects and electromagnetic field generated from the three dimensional plasma oscillation. The large amplitude plasma oscillation dynamics produced by a bunched relativistic electron beam with arbitrary transverse profile - plasma wave field (PWF) - or by a high power single frequency short electromagnetic pulse with arbitrary transverse profile - electromagnetic plasma wake field (EPWF) - may be described by means of the present theory. (orig.)

  8. Bispectral analysis of nonlinear compressional waves in a two-dimensional dusty plasma crystal

    International Nuclear Information System (INIS)

    Nosenko, V.; Goree, J.; Skiff, F.

    2006-01-01

    Bispectral analysis was used to study the nonlinear interaction of compressional waves in a two-dimensional strongly coupled dusty plasma. A monolayer of highly charged polymer microspheres was suspended in a plasma sheath. The microspheres interacted with a Yukawa potential and formed a triangular lattice. Two sinusoidal pump waves with different frequencies were excited in the lattice by pushing the particles with modulated Ar + laser beams. Coherent nonlinear interaction of the pump waves was shown to be the mechanism of generating waves at the sum, difference, and other combination frequencies. However, coherent nonlinear interaction was ruled out for certain combination frequencies, in particular, for the difference frequency below an excitation-power threshold, as predicted by theory

  9. Spontaneous disordering of a two-dimensional (2D) plasma crystal

    International Nuclear Information System (INIS)

    Zhdanov, Sergey K; Thoma, Markus H; Morfill, Gregor E

    2011-01-01

    Spontaneous disordering plays an important role in the physics of highly ordered complex plasmas. In this paper, an analytical theory is proposed for the process of 'cold amorphization', which has been observed. This consists of splitting a plasma crystal into sub-domains, followed by disordering. The results of recent simulations and experiments showing such spontaneous disordering have been reviewed and interpreted in this paper. Complex plasmas can serve as a powerful tool providing fundamental insight into this process generically.

  10. New approach in two-dimensional fluid modeling of edge plasma transport with high intermittency due to blobs and edge localized modes

    International Nuclear Information System (INIS)

    Pigarov, A. Yu.; Krasheninnikov, S. I.; Rognlien, T. D.

    2011-01-01

    A new approach is proposed to simulate intermittent, non-diffusive plasma transport (via blobs and filaments of edge localized modes (ELMs)) observed in the tokamak edge region within the framework of two-dimensional transport codes. This approach combines the inherently three-dimensional filamentary structures associated with an ensemble of blobs into a macro-blob in the two-dimensional poloidal cross-section and advects the macro-blob ballistically across the magnetic field, B. Intermittent transport is represented as a sequence of macro-blobs appropriately seeded in the edge plasma according to experimental statistics. In this case, the code is capable of reproducing both the long-scale temporal evolution of the background plasma and the fast spatiotemporal dynamics of blobs. We report the results from a two-dimensional edge plasma code modeling of a single macro-blob dynamics, and its interaction with initially stationary background plasma as well as with material surfaces. The mechanisms of edge plasma particle and energy losses from macro-blobs are analyzed. The effects of macro-blob sizes and advection velocity on edge plasma profiles are studied. The macro-blob impact on power loading and sputtering rates on the chamber wall and on inner and outer divertor plates is discussed. Temporal evolution of particle inventory of the edge plasma perturbed by macro-blobs is analyzed. Application of macro-blobs to ELM modeling is highlighted.

  11. Collisional plasma transport: two-dimensional scalar formulation of the initial boundary value problem and quasi one-dimensional models

    International Nuclear Information System (INIS)

    Mugge, J.W.

    1979-10-01

    The collisional plasma transport problem is formulated as an initial boundary value problem for general characteristic boundary conditions. Starting from the full set of hydrodynamic and electrodynamic equations an expansion in the electron-ion mass ratio together with a multiple timescale method yields simplified equations on each timescale. On timescales where many collisions have taken place for the simplified equations the initial boundary value problem is formulated. Through the introduction of potentials a two-dimensional scalar formulation in terms of quasi-linear integro-differential equations of second order for a domain consisting of plasma and vacuum sub-domains is obtained. (Auth.)

  12. Characterization of the supersonic flowing microwave discharge using two dimensional plasma tomography

    Energy Technology Data Exchange (ETDEWEB)

    Nikolic, M.; Samolov, A.; Popovic, S.; Vuskovic, L.; Godunov, A. [Department of Physics, Center for Accelerator Science, Old Dominion University, Norfolk, Virginia 23529 (United States); Cuckov, F. [Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, Virginia 23529 (United States)

    2013-03-14

    A tomographic numerical method based on the two-dimensional Radon formula for a cylindrical cavity has been employed for obtaining spatial distributions of the argon excited levels. The spectroscopy measurements were taken at different positions and directions to observe populations of excited species in the plasmoid region and the corresponding excitation temperatures. Excited argon states are concentrated near the tube walls, thus, confirming the assumption that the post discharge plasma is dominantly sustained by travelling surface wave. An automated optical measurement system has been developed for reconstruction of local plasma parameters of the plasmoid structure formed in an argon supersonic flowing microwave discharge. The system carries out angle and distance measurements using a rotating, flat mirror, as well as two high precision stepper motors operated by a microcontroller-based system and several sensors for precise feedback control.

  13. Complex Plasma Research Under Extreme Conditions

    International Nuclear Information System (INIS)

    Ishihara, Osamu

    2008-01-01

    Complex plasma research under extreme conditions is described. The extreme conditions include low-dimensionality for self-organized structures of dust particles, dust magnetization in high magnetic field, criticality in phase transition, and cryogenic environment for Coulomb crystals and dust dynamics.

  14. Two dimensional radial gas flows in atmospheric pressure plasma-enhanced chemical vapor deposition

    Science.gov (United States)

    Kim, Gwihyun; Park, Seran; Shin, Hyunsu; Song, Seungho; Oh, Hoon-Jung; Ko, Dae Hong; Choi, Jung-Il; Baik, Seung Jae

    2017-12-01

    Atmospheric pressure (AP) operation of plasma-enhanced chemical vapor deposition (PECVD) is one of promising concepts for high quality and low cost processing. Atmospheric plasma discharge requires narrow gap configuration, which causes an inherent feature of AP PECVD. Two dimensional radial gas flows in AP PECVD induces radial variation of mass-transport and that of substrate temperature. The opposite trend of these variations would be the key consideration in the development of uniform deposition process. Another inherent feature of AP PECVD is confined plasma discharge, from which volume power density concept is derived as a key parameter for the control of deposition rate. We investigated deposition rate as a function of volume power density, gas flux, source gas partial pressure, hydrogen partial pressure, plasma source frequency, and substrate temperature; and derived a design guideline of deposition tool and process development in terms of deposition rate and uniformity.

  15. 'Complexity' and anomalous transport in space plasmas

    International Nuclear Information System (INIS)

    Chang, Tom; Wu Chengchin

    2002-01-01

    'Complexity' has become a hot topic in nearly every field of modern physics. Space plasma is of no exception. In this paper, it is demonstrated that the sporadic and localized interactions of magnetic coherent structures are the origin of 'complexity' in space plasmas. The intermittent localized interactions, which generate the anomalous diffusion, transport, and evolution of the macroscopic state variables of the overall dynamical system, may be modeled by a triggered (fast) localized chaotic growth equation of a set of relevant order parameters. Such processes would generally pave the way for the global system to evolve into a 'complex' state of long-ranged interactions of fluctuations, displaying the phenomenon of forced and/or self-organized criticality. An example of such type of anomalous transport and evolution in a sheared magnetic field is provided via two-dimensional magnetohydrodynamic simulations. The coarse-grained dissipation due to the intermittent triggered interactions among the magnetic coherent structures induces a 'fluctuation-induced nonlinear instability' that reconfigures the sheared magnetic field into an X-point magnetic geometry (in the mean field sense), leading to the anomalous acceleration of the magnetic coherent structures. A phenomenon akin to such type of anomalous transport and acceleration, the so-called bursty bulk flows, has been commonly observed in the plasma sheet of the Earth's magnetotail

  16. Terahertz Plasma Waves in Two Dimensional Quantum Electron Gas with Electron Scattering

    International Nuclear Information System (INIS)

    Zhang Liping

    2015-01-01

    We investigate the Terahertz (THz) plasma waves in a two-dimensional (2D) electron gas in a nanometer field effect transistor (FET) with quantum effects, the electron scattering, the thermal motion of electrons and electron exchange-correlation. We find that, while the electron scattering, the wave number along y direction and the electron exchange-correlation suppress the radiation power, but the thermal motion of electrons and the quantum effects can amplify the radiation power. The radiation frequency decreases with electron exchange-correlation contributions, but increases with quantum effects, the wave number along y direction and thermal motion of electrons. It is worth mentioning that the electron scattering has scarce influence on the radiation frequency. These properties could be of great help to the realization of practical THz plasma oscillations in nanometer FET. (paper)

  17. ENERGY DISSIPATION AND LANDAU DAMPING IN TWO- AND THREE-DIMENSIONAL PLASMA TURBULENCE

    Energy Technology Data Exchange (ETDEWEB)

    Li, Tak Chu; Howes, Gregory G. [Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52242 (United States); Klein, Kristopher G. [Space Science Center, University of New Hampshire, Durham, NH 03824 (United States); TenBarge, Jason M. [IREAP, University of Maryland, College Park, MD 20742 (United States)

    2016-12-01

    Plasma turbulence is ubiquitous in space and astrophysical plasmas, playing an important role in plasma energization, but the physical mechanisms leading to dissipation of the turbulent energy remain to be definitively identified. Kinetic simulations in two dimensions (2D) have been extensively used to study the dissipation process. How the limitation to 2D affects energy dissipation remains unclear. This work provides a model of comparison between two- and three-dimensional (3D) plasma turbulence using gyrokinetic simulations; it also explores the dynamics of distribution functions during the dissipation process. It is found that both 2D and 3D nonlinear gyrokinetic simulations of a low-beta plasma generate electron velocity-space structures with the same characteristics as that of the linear Landau damping of Alfvén waves in a 3D linear simulation. The continual occurrence of the velocity-space structures throughout the turbulence simulations suggests that the action of Landau damping may be responsible for the turbulent energy transfer to electrons in both 2D and 3D, and makes possible the subsequent irreversible heating of the plasma through collisional smoothing of the velocity-space fluctuations. Although, in the 2D case where variation along the equilibrium magnetic field is absent, it may be expected that Landau damping is not possible, a common trigonometric factor appears in the 2D resonant denominator, leaving the resonance condition unchanged from the 3D case. The evolution of the 2D and 3D cases is qualitatively similar. However, quantitatively, the nonlinear energy cascade and subsequent dissipation is significantly slower in the 2D case.

  18. Discriminating image textures with the multiscale two-dimensional complexity-entropy causality plane

    International Nuclear Information System (INIS)

    Zunino, Luciano; Ribeiro, Haroldo V.

    2016-01-01

    The aim of this paper is to further explore the usefulness of the two-dimensional complexity-entropy causality plane as a texture image descriptor. A multiscale generalization is introduced in order to distinguish between different roughness features of images at small and large spatial scales. Numerically generated two-dimensional structures are initially considered for illustrating basic concepts in a controlled framework. Then, more realistic situations are studied. Obtained results allow us to confirm that intrinsic spatial correlations of images are successfully unveiled by implementing this multiscale symbolic information-theory approach. Consequently, we conclude that the proposed representation space is a versatile and practical tool for identifying, characterizing and discriminating image textures.

  19. Quantum theory of longitudinal dielectric response properties of a two-dimensional plasma in a magnetic field

    International Nuclear Information System (INIS)

    Horing, N.J.M.; Yildiz, M.M.

    1976-01-01

    An analysis of dynamic and nonlocal longitudinal dielectric response properties of a two-dimensional Landau-quantized plasma is carried out, using a thermodynamic Green's function formulation of the RPA with a two-dimensional thermal Green's function for electron propagation in a magnetic field developed in closed form. The longitudinal-electrostatic plasmon dispersion relation is discussed in the low wave-number regime with nonlocal corrections, and Bernstein mode structure is studied for arbitrary wavenumber. All regimes of magnetic field strength and statistics are investigated. The class of integrals treated here should have broad applicability in other two-dimensional and finite slab plasma studies.The two-dimensional static shielding law in a magnetic field is analyzed for low wavenumber, and for large distances we find V (r) approx. = Q/k 2 2 r 3 . The inverse screening length k 0 =2πe 2 partial rho/ partialxi (rho= density, xi= chemical potential) is evaluated in all regimes of magnetic field strength and all statistical regimes. k 0 exhibits violent DHVA oscillatory behavior in the degenerate zero-temperature case at higher field strengths, and the shielding is complete when xi =r'hω/subc/ but there is no shielding when xi does not = r'hω/subc/. A careful analysis confirms that there is no shielding at large distances in the degenerate quantum strong field limit h3π/subc/>xi. Since shielding does persist in the nondegenerate quantum strong field limit hω/subc/>KT, there should be a pronounced change in physical properties that depend on shielding if the system is driven through a high field statistical transition. Finally, we find that the zero field two-dimensional Friedel--Kohn ''wiggle'' static shielding phenomenon is destroyed by the dispersal of the zero field continuum of electron states into the discrete set of Landau-quantized orbitals due to the imposition of the magnetic field

  20. Note: Interpolation for evaluation of a two-dimensional spatial profile of plasma densities at low gas pressures

    International Nuclear Information System (INIS)

    Oh, Se-Jin; Kim, Young-Chul; Chung, Chin-Wook

    2011-01-01

    An interpolation algorithm for the evaluation of the spatial profile of plasma densities in a cylindrical reactor was developed for low gas pressures. The algorithm is based on a collisionless two-dimensional fluid model. Contrary to the collisional case, i.e., diffusion fluid model, the fitting algorithm depends on the aspect ratio of the cylindrical reactor. The spatial density profile of the collisionless fitting algorithm is presented in two-dimensional images and compared with the results of the diffusion fluid model.

  1. Wave dispersion relation of two-dimensional plasma crystals in a magnetic field

    International Nuclear Information System (INIS)

    Uchida, G.; Konopka, U.; Morfill, G.

    2004-01-01

    The wave dispersion relation in a two-dimensional strongly coupled plasma crystal is studied by theoretical analysis and molecular dynamics simulation taking into account a constant magnetic field parallel to the crystal normal. The expression for the wave dispersion relation clearly shows that high-frequency and low-frequency branches exist as a result of the coupling of longitudinal and transverse modes due to the Lorenz force acting on the dust particles. The high-frequency and the low-frequency branches are found to belong to right-hand and left-hand polarized waves, respectively

  2. TWO-DIMENSIONAL CELLULAR AUTOMATON MODEL FOR THE EVOLUTION OF ACTIVE REGION CORONAL PLASMAS

    Energy Technology Data Exchange (ETDEWEB)

    López Fuentes, Marcelo [Instituto de Astronomía y Física del Espacio, CONICET-UBA, CC. 67, Suc. 28, 1428 Buenos Aires (Argentina); Klimchuk, James A., E-mail: lopezf@iafe.uba.ar [NASA Goddard Space Flight Center, Code 671, Greenbelt, MD 20771 (United States)

    2015-02-01

    We study a two-dimensional cellular automaton (CA) model for the evolution of coronal loop plasmas. The model is based on the idea that coronal loops are made of elementary magnetic strands that are tangled and stressed by the displacement of their footpoints by photospheric motions. The magnetic stress accumulated between neighbor strands is released in sudden reconnection events or nanoflares that heat the plasma. We combine the CA model with the Enthalpy Based Thermal Evolution of Loops model to compute the response of the plasma to the heating events. Using the known response of the X-Ray Telescope on board Hinode, we also obtain synthetic data. The model obeys easy-to-understand scaling laws relating the output (nanoflare energy, temperature, density, intensity) to the input parameters (field strength, strand length, critical misalignment angle). The nanoflares have a power-law distribution with a universal slope of –2.5, independent of the input parameters. The repetition frequency of nanoflares, expressed in terms of the plasma cooling time, increases with strand length. We discuss the implications of our results for the problem of heating and evolution of active region coronal plasmas.

  3. New Developments In Particle Image Velocimetry (PIV) For The Study Of Complex Plasmas

    International Nuclear Information System (INIS)

    Thomas, Edward Jr.; Fisher, Ross; Shaw, Joseph; Jefferson, Robert; Cianciosa, Mark; Williams, Jeremiah

    2011-01-01

    Particle Image Velocimetry (PIV) is a fluid measurement technique in which the average displacement of small groups of particles is made by comparing a pair of images that are separated in time by an interval Δt. For over a decade, a several variations of the PIV technique, e.g., two-dimensional, stereoscopic, and tomographic PIV, have been used to characterize particle transport, instabilities, and the thermal properties of complex plasmas. This paper describes the basic principles involved in the PIV analysis technique and discusses potential future applications of PIV to the study of complex plasmas.

  4. Canonical Groups for Quantization on the Two-Dimensional Sphere and One-Dimensional Complex Projective Space

    International Nuclear Information System (INIS)

    Sumadi A H A; H, Zainuddin

    2014-01-01

    Using Isham's group-theoretic quantization scheme, we construct the canonical groups of the systems on the two-dimensional sphere and one-dimensional complex projective space, which are homeomorphic. In the first case, we take SO(3) as the natural canonical Lie group of rotations of the two-sphere and find all the possible Hamiltonian vector fields, and followed by verifying the commutator and Poisson bracket algebra correspondences with the Lie algebra of the group. In the second case, the same technique is resumed to define the Lie group, in this case SU (2), of CP'.We show that one can simply use a coordinate transformation from S 2 to CP 1 to obtain all the Hamiltonian vector fields of CP 1 . We explicitly show that the Lie algebra structures of both canonical groups are locally homomorphic. On the other hand, globally their corresponding canonical groups are acting on different geometries, the latter of which is almost complex. Thus the canonical group for CP 1 is the double-covering group of SO(3), namely SU(2). The relevance of the proposed formalism is to understand the idea of CP 1 as a space of where the qubit lives which is known as a Bloch sphere

  5. Modelling of oscillations in two-dimensional echo-spectra of the Fenna-Matthews-Olson complex

    International Nuclear Information System (INIS)

    Hein, Birgit; Kreisbeck, Christoph; Kramer, Tobias; Rodríguez, Mirta

    2012-01-01

    Recent experimental observations of time-dependent beatings in the two-dimensional echo-spectra of light-harvesting complexes at ambient temperatures have opened up the question of whether coherence and wave-like behaviour play a significant role in photosynthesis. We carry out a numerical study of the absorption and echo-spectra of the Fenna-Matthews-Olson (FMO) complex in Chlorobium tepidum and analyse the requirements in the theoretical model needed to reproduce beatings in the calculated spectra. The energy transfer in the FMO pigment-protein complex is theoretically described by an exciton Hamiltonian coupled to a phonon bath which accounts for the pigments' electronic and vibrational excitations, respectively. We use the hierarchical equations of motions method to treat the strong couplings in a non-perturbative way. We show that the oscillations in the two-dimensional echo-spectra persist in the presence of thermal noise and static disorder. (paper)

  6. Convergence of numerical schemes suitable for two dimensional nonlinear convection: application to the coupling of modes in a plasma

    International Nuclear Information System (INIS)

    Boukadida, T.

    1988-01-01

    The compatibility between accuracy and stability of the quasilinear equations is studied. Three stuations are analyzed: the discontinuous P-1 approximation of the first order quasilinear equation, the two dimensional version of the Lax-Friedrichs scheme and the coupling of modes in a plasma. For the one dimensional case, the proposed scheme matches the available data. In the two dimensional case, tests to show the explosion condition are performed. This investigation can be applied in laser-matter interactions, nonlinear optics and in many fields of physics [fr

  7. Complex Quasi-Two-Dimensional Crystalline Order Embedded in VO2 and Other Crystals

    Science.gov (United States)

    Lovorn, Timothy; Sarker, Sanjoy K.

    2017-07-01

    Metal oxides such as VO2 undergo structural transitions to low-symmetry phases characterized by intricate crystalline order, accompanied by rich electronic behavior. We derive a minimal ionic Hamiltonian based on symmetry and local energetics which describes structural transitions involving all four observed phases, in the correct order. An exact analysis shows that complexity results from the symmetry-induced constraints of the parent phase, which forces ionic displacements to form multiple interpenetrating groups using low-dimensional pathways and distant neighbors. Displacements within each group exhibit independent, quasi-two-dimensional order, which is frustrated and fragile. This selective ordering mechanism is not restricted to VO2 : it applies to other oxides that show similar complex order.

  8. A method of paralleling computer calculation for two-dimensional kinetic plasma model

    International Nuclear Information System (INIS)

    Brazhnik, V.A.; Demchenko, V.V.; Dem'yanov, V.G.; D'yakov, V.E.; Ol'shanskij, V.V.; Panchenko, V.I.

    1987-01-01

    A method for parallel computer calculation and OSIRIS program complex realizing it and designed for numerical plasma simulation by the macroparticle method are described. The calculation can be carried out either with one or simultaneously with two computers BESM-6, that is provided by some package of interacting programs functioning in every computer. Program interaction in every computer is based on event techniques realized in OS DISPAK. Parallel computer calculation with two BESM-6 computers allows to accelerate the computation 1.5 times

  9. Interaction of Electromagnetic Waves with Two-Dimensional Metal Covered with Radar Absorbing Material and Plasma

    International Nuclear Information System (INIS)

    Lan Chaohui; Hu Xiwei; Jiang Zhonghe

    2008-01-01

    A two-dimensional metal model is established to investigate the stealth mechanisms of radar absorbing material (RAM) and plasma when they cover the model together. Using the finite-difference time-domain (FDTD) method, the interaction of electromagnetic (EM) waves with the model can be studied. In this paper, three covering cases are considered: a. RAM or plasma covering the metal solely; b. RAM and plasma covering the metal, while plasma is placed outside; c. RAM and plasma covering the metal, while RAM is placed outside. The calculated results show that the covering order has a great influence on the absorption of EM waves. Compared to case a, case b has an advantage in the absorption of relatively high-frequency EM waves (HFWs), whereas case c has an advantage in the absorption of relatively low-frequency EM waves (LFWs). Through the optimization of the parameters of both plasma and RAM, it is hopeful to obtain a broad absorption band by RAM and plasma covering. Near-field attenuation rate and far-field radar cross section (RCS) are employed to compare the different cases. (low temperature plasma)

  10. Complexes of dipolar excitons in layered quasi-two-dimensional nanostructures

    Science.gov (United States)

    Bondarev, Igor V.; Vladimirova, Maria R.

    2018-04-01

    We discuss neutral and charged complexes (biexcitons and trions) formed by indirect excitons in layered quasi-two-dimensional semiconductor heterostructures. Indirect excitons—long-lived neutral Coulomb-bound pairs of electrons and holes of different layers—have been known for semiconductor coupled quantum wells and have recently been reported for van der Waals heterostructures such as double bilayer graphene and transition-metal dichalcogenides. Using the configuration space approach, we derive the analytical expressions for the trion and biexciton binding energies as a function of interlayer distance. The method captures essential kinematics of complex formation to reveal significant binding energies, up to a few tens of meV for typical interlayer distances ˜3 -5 Å , with the trion binding energy always being greater than that of the biexciton. Our results can contribute to the understanding of more complex many-body phenomena such as exciton Bose-Einstein condensation and Wigner-like electron-hole crystallization in layered semiconductor heterostructures.

  11. Viscosity of two-dimensional strongly coupled dusty plasma modified by a perpendicular magnetic field

    Science.gov (United States)

    Feng, Yan; Lin, Wei; Murillo, M. S.

    2017-11-01

    Transport properties of two-dimensional (2D) strongly coupled dusty plasmas have been investigated in detail, but never for viscosity with a strong perpendicular magnetic field; here, we examine this scenario using Langevin dynamics simulations of 2D liquids with a binary Yukawa interparticle interaction. The shear viscosity η of 2D liquid dusty plasma is estimated from the simulation data using the Green-Kubo relation, which is the integration of the shear stress autocorrelation function. It is found that, when a perpendicular magnetic field is applied, the shear viscosity of 2D liquid dusty plasma is modified substantially. When the magnetic field is increased, its viscosity increases at low temperatures, while at high temperatures its viscosity diminishes. It is determined that these different variational trends of η arise from the different behaviors of the kinetic and potential parts of the shear stress under external magnetic fields.

  12. Structures and Dynamics of Two-Dimensional Dust Lattices with and without Coulomb Molecules in Plasmas

    International Nuclear Information System (INIS)

    Huang Feng; Wang Xue-Jin; Liu Yan-Hong; Ye Mao-Fu; Wang Long

    2010-01-01

    Structures and dynamics of two-dimensional dust lattices with and without Coulomb molecules in plasmas are investigated. The experimental results show that the lattices have the crystal-like hexagonal structures, i.e. most particles have six nearest-neighboring particles. However, the lattice points can be occupied by the individual particles or by a pair of particles called Coulomb molecules. The pair correlation function is used to compare the structures between the lattices with or without the Coulomb molecules. In the experiments, the Coulomb molecules can also decompose and recombine with another individual particle to form a new molecule. (physics of gases, plasmas, and electric discharges)

  13. Relaxation and self-organization in two-dimensional plasma and neutral fluid flow systems

    International Nuclear Information System (INIS)

    Das, Amita

    2008-01-01

    Extensive numerical studies in the framework of a simplified two-dimensional model for neutral and plasma fluid for a variety of initial configurations and for both decaying and driven cases are carried out to illustrate relaxation toward a self-organized state. The dynamical model equation constitutes a simple choice for this purpose, e.g., the vorticity equation of the Navier-Stokes dynamics for the incompressible neutral fluids and the Hasegawa-Mima equation for plasma fluid flow system. Scatter plots are employed to observe a development of functional relationship, if any, amidst the generalized vorticity and its Laplacian. It is seen that they do not satisfy a linear relationship as the well known variational approach of enstrophy minimization subject to constancy of the energy integral for the two-dimensional (2D) system suggests. The observed nonlinear functional relationship is understood by separating the contribution to the scatter plot from spatial regions with intense vorticity patches and those of the background flow region where the background vorticity is weak or absent altogether. It is shown that such a separation has close connection with the known exact analytical solutions of the system. The analytical solutions are typically obtained by assuming a finite source of vorticity for the inner core of the localized structure, which is then matched with the solution in the outer region where vorticity is chosen to be zero. The work also demonstrates that the seemingly ad hoc choice of the linear vorticity source function for the inner region is in fact consistent with the self-organization paradigm of the 2D systems

  14. Lessons from non-Abelian plasma instabilities in two spatial dimensions

    International Nuclear Information System (INIS)

    Arnold, Peter; Leang, P.-S.

    2007-01-01

    Plasma instabilities can play a fundamental role in quark-gluon plasma equilibration in the high energy (weak coupling) limit. Early simulations of the evolution of plasma instabilities in non-Abelian gauge theory, performed in one spatial dimension, found behavior qualitatively similar to traditional QED plasmas. Later simulations of the fully three-dimensional theory found different behavior, unlike traditional QED plasmas. To shed light on the origin of this difference, we study the intermediate case of two spatial dimensions. Depending on how the 'two-dimensional' theory is formulated, we can obtain either behavior

  15. Two dimensional Hall MHD modeling of a plasma opening switch with density inhomogeneities

    Energy Technology Data Exchange (ETDEWEB)

    Zabaidullin, O [Kurchatov Institute, Moscow (Russian Federation); Chuvatin, A; Etlicher, B [Ecole Polytechnique, Palaiseau (France). Laboratoire de Physique des Milieux Ionises

    1997-12-31

    The results of two-dimensional numerical modeling of the Plasma Opening Switch in the MHD framework with Hall effect are presented. An enhanced Hall diffusion coefficient was used in the simulations. Recent experiments justify the application of this approach. The result of the modeling also correlates better with the experiment than in the case of the classical diffusion coefficient. Numerically generated pictures propose a switching scenario in which the translation between the conduction and opening phases can be explained by an abrupt `switching on` and further domination of the Hall effect at the end of the conduction phase. (author). 3 figs., 6 refs.

  16. Hamiltonian field description of two-dimensional vortex fluids and guiding center plasmas

    International Nuclear Information System (INIS)

    Morrison, P.J.

    1981-03-01

    The equations that describe the motion of two-dimensional vortex fluids and guiding center plasmas are shown to possess underlying field Hamiltonian structure. A Poisson bracket which is given in terms of the vorticity, the physical although noncanonical dynamical variable, casts these equations into Heisenberg form. The Hamiltonian density is the kinetic energy density of the fluid. The well-known conserved quantities are seen to be in involution with respect to this Poisson bracket. Expanding the vorticity in terms of a Fourier-Dirac series transforms the field description given here into the usual canonical equations for discrete vortex motion. A Clebsch potential representation of the vorticity transforms the noncanonical field description into a canonical description

  17. Effect of shape of scatterers and plasma frequency on the complete photonic band gap properties of two-dimensional dielectric-plasma photonic crystals

    Energy Technology Data Exchange (ETDEWEB)

    Fathollahi Khalkhali, T., E-mail: tfathollahi@aeoi.org.ir; Bananej, A.

    2016-12-16

    In this study, we analyze complete photonic band gap properties of two-dimensional dielectric-plasma photonic crystals with triangular and square lattices, composed of plasma rods with different geometrical shapes in the anisotropic tellurium background. Using the finite-difference time-domain method we discuss the maximization of the complete photonic band gap width as a function of plasma frequency and plasma rods parameters with different shapes and orientations. The numerical results demonstrate that our proposed structures represent significantly wide complete photonic band gaps in comparison to previously studied dielectric-plasma photonic crystals. - Highlights: • In this paper, we have investigated plasma photonic crystals. • Plasma is a kind of dispersive medium with its equivalent refractive index related to the frequency of an incident EM wave. • In this work, our simulations are performed using the Meep implementation of the finite-difference time-domain (FDTD) method. • For this study, the lattice structures investigated are triangular and square. • Extensive calculations reveal that almost all of these structures represent wide complete band gaps.

  18. Effect of shape of scatterers and plasma frequency on the complete photonic band gap properties of two-dimensional dielectric-plasma photonic crystals

    International Nuclear Information System (INIS)

    Fathollahi Khalkhali, T.; Bananej, A.

    2016-01-01

    In this study, we analyze complete photonic band gap properties of two-dimensional dielectric-plasma photonic crystals with triangular and square lattices, composed of plasma rods with different geometrical shapes in the anisotropic tellurium background. Using the finite-difference time-domain method we discuss the maximization of the complete photonic band gap width as a function of plasma frequency and plasma rods parameters with different shapes and orientations. The numerical results demonstrate that our proposed structures represent significantly wide complete photonic band gaps in comparison to previously studied dielectric-plasma photonic crystals. - Highlights: • In this paper, we have investigated plasma photonic crystals. • Plasma is a kind of dispersive medium with its equivalent refractive index related to the frequency of an incident EM wave. • In this work, our simulations are performed using the Meep implementation of the finite-difference time-domain (FDTD) method. • For this study, the lattice structures investigated are triangular and square. • Extensive calculations reveal that almost all of these structures represent wide complete band gaps.

  19. Parametric study of nonlinear electrostatic waves in two-dimensional quantum dusty plasmas

    International Nuclear Information System (INIS)

    Ali, S; Moslem, W M; Kourakis, I; Shukla, P K

    2008-01-01

    The nonlinear properties of two-dimensional cylindrical quantum dust-ion-acoustic (QDIA) and quantum dust-acoustic (QDA) waves are studied in a collisionless, unmagnetized and dense (quantum) dusty plasma. For this purpose, the reductive perturbation technique is employed to the quantum hydrodynamical equations and the Poisson equation, obtaining the cylindrical Kadomtsev-Petviashvili (CKP) equations. The effects of quantum diffraction, as well as quantum statistical and geometric effects on the profiles of QDIA and QDA solitary waves are examined. It is found that the amplitudes and widths of the nonplanar QDIA and QDA waves are significantly affected by the quantum electron tunneling effect. The addition of a dust component to a quantum plasma is seen to affect the propagation characteristics of localized QDIA excitations. In the case of low-frequency QDA waves, this effect is even stronger, since the actual form of the potential solitary waves, in fact, depends on the dust charge polarity (positive/negative) itself (allowing for positive/negative potential forms, respectively). The relevance of the present investigation to metallic nanostructures is highlighted

  20. Two-dimensional particle-in-cell simulation of the expansion of a plasma into a rarefied medium

    Energy Technology Data Exchange (ETDEWEB)

    Sarri, G; Quinn, K; Kourakis, I; Borghesi, M [Centre for Plasma Physics, The Queens University of Belfast, Belfast BT7 1NN (United Kingdom); Murphy, G C; Drury, L O C [Dublin Institute for Advanced Studies, 31 Fitzwilliam Place, Dublin 2 (Ireland); Dieckmann, M E; Ynnerman, A [Department of Science and Technology (ITN), Linkoeping University, 60174 Norrkoping (Sweden); Bret, A, E-mail: gsarri01@qub.ac.uk [ETSI Industriales, Universidad de Castilla-La Mancha, 13071 Ciudad Real (Spain)

    2011-07-15

    The expansion of a dense plasma through a more rarefied ionized medium has been studied by means of two-dimensional particle-in-cell simulations. The initial conditions involve a density jump by a factor of 100, located in the middle of an otherwise equally dense electron-proton plasma with uniform proton and electron temperatures of 10 eV and 1 keV, respectively. Simulations show the creation of a purely electrostatic collisionless shock together with an ion-acoustic soliton tied to its downstream region. The shock front is seen to evolve in filamentary structures consistently with the onset of the ion-ion instability. Meanwhile, an un-magnetized drift instability is triggered in the core part of the dense plasma. Such results explain recent experimental laser-plasma experiments, carried out in similar conditions, and are of intrinsic relevance to non-relativistic shock scenarios in the solar and astrophysical systems.

  1. Two-dimensional particle-in-cell simulation of the expansion of a plasma into a rarefied medium

    International Nuclear Information System (INIS)

    Sarri, G; Quinn, K; Kourakis, I; Borghesi, M; Murphy, G C; Drury, L O C; Dieckmann, M E; Ynnerman, A; Bret, A

    2011-01-01

    The expansion of a dense plasma through a more rarefied ionized medium has been studied by means of two-dimensional particle-in-cell simulations. The initial conditions involve a density jump by a factor of 100, located in the middle of an otherwise equally dense electron-proton plasma with uniform proton and electron temperatures of 10 eV and 1 keV, respectively. Simulations show the creation of a purely electrostatic collisionless shock together with an ion-acoustic soliton tied to its downstream region. The shock front is seen to evolve in filamentary structures consistently with the onset of the ion-ion instability. Meanwhile, an un-magnetized drift instability is triggered in the core part of the dense plasma. Such results explain recent experimental laser-plasma experiments, carried out in similar conditions, and are of intrinsic relevance to non-relativistic shock scenarios in the solar and astrophysical systems.

  2. Numerical study on the two-dimensional flows of plasma and ionizing gas using trial particles

    International Nuclear Information System (INIS)

    Brushlinskij, K.V.; Kozlov, A.N.; Morozov, A.I.

    1985-01-01

    Two-dimensional flows of plasma and ionized αs in a channel between two coaxial electrodes are considered in the MHD-model with account of Hall effect. Stationary solutions of the problem on the flow are obtained either analytically in approximation of a ''smooth'' channel - for ideal conducting plasma, or numerically using the methos of establishment - in the ge-neral case of finite conductivity. A method of further numerical analysis of some peculiarities of flow is suggested in the paper. It is based on studying dynamics of single ''test'' particles in fields of the main MHD plasma flow. Trajectory of the test ion is calculated with account for interaction forces with earlier determined electromagentic field and friction responsible for Coulomb collisions with particles of the background flow. The calculations display trajectories of test particles with different masses, initial positions and initial rates. They are shown to be dose to current lines of background medium in plasma of finite conductivity, that testified to the virtue of effectiveness of the MHD-model. In case of ideal conductivity trajectories of test and background particles can noticeably differ from one another. Stabilization effects of motion of particles accidentally knocked out from the flow and separation of pariticles of different mass by electromao.netic forces are considered

  3. Plasma properties of quasi-one-dimensional ring

    CERN Document Server

    Shmelev, G M

    2001-01-01

    The plasma properties of the quasi-one-dimensional ring in the threshold cases of low and high frequencies, corresponding to the plasma oscillations and dielectric relaxation are studied within the frames of the classical approach. The plasma oscillations spectrum and the electron dielectric relaxation frequency in the quasi-one-dimensional ring are calculated. The plasmons spectrum equidistance is identified. It is shown , that in contrast to the three-dimensional case there takes place the dielectric relaxation dispersion, wherefrom there follows the possibility of studying the carriers distribution in the quasi-one-dimensional rings through the method of the dielectric relaxation spectroscopy

  4. Global parameter optimization of a Mather-type plasma focus in the framework of the Gratton–Vargas two-dimensional snowplow model

    International Nuclear Information System (INIS)

    Auluck, S K H

    2014-01-01

    Dense plasma focus (DPF) is known to produce highly energetic ions, electrons and plasma environment which can be used for breeding short-lived isotopes, plasma nanotechnology and other material processing applications. Commercial utilization of DPF in such areas would need a design tool that can be deployed in an automatic search for the best possible device configuration for a given application. The recently revisited (Auluck 2013 Phys. Plasmas 20 112501) Gratton–Vargas (GV) two-dimensional analytical snowplow model of plasma focus provides a numerical formula for dynamic inductance of a Mather-type plasma focus fitted to thousands of automated computations, which enables the construction of such a design tool. This inductance formula is utilized in the present work to explore global optimization, based on first-principles optimality criteria, in a four-dimensional parameter-subspace of the zero-resistance GV model. The optimization process is shown to reproduce the empirically observed constancy of the drive parameter over eight decades in capacitor bank energy. The optimized geometry of plasma focus normalized to the anode radius is shown to be independent of voltage, while the optimized anode radius is shown to be related to capacitor bank inductance. (paper)

  5. FPGA Implementation of one-dimensional and two-dimensional cellular automata

    International Nuclear Information System (INIS)

    D'Antone, I.

    1999-01-01

    This report describes the hardware implementation of one-dimensional and two-dimensional cellular automata (CAs). After a general introduction to the cellular automata, we consider a one-dimensional CA used to implement pseudo-random techniques in built-in self test for VLSI. Due to the increase in digital ASIC complexity, testing is becoming one of the major costs in the VLSI production. The high electronics complexity, used in particle physics experiments, demands higher reliability than in the past time. General criterions are given to evaluate the feasibility of the circuit used for testing and some quantitative parameters are underlined to optimize the architecture of the cellular automaton. Furthermore, we propose a two-dimensional CA that performs a peak finding algorithm in a matrix of cells mapping a sub-region of a calorimeter. As in a two-dimensional filtering process, the peaks of the energy clusters are found in one evolution step. This CA belongs to Wolfram class II cellular automata. Some quantitative parameters are given to optimize the architecture of the cellular automaton implemented in a commercial field programmable gate array (FPGA)

  6. 3D Diagnostic Of Complex Plasma

    International Nuclear Information System (INIS)

    Hall, Edward; Samsonov, Dmitry

    2011-01-01

    This paper reports the development of a three-dimensional(3D) dust particle position diagnostic for complex plasmas. A beam produce by Light Emitting Diodes(LEDs) is formed into horizontal sheet, for the illumination of the particles. The light sheet has a vertical colour gradient across its width, from two opposing colours. The light scattered from the particles is imaged with the camera from above. The horizontal coordinates are measured from the positions on the image. The third coordinate is determined from the colour which represents a position on the gradient of the light sheet. The use of LEDs as a light source reduces a variation in Mie scattered intensity from the particles due to the particle size distribution. The variation would induce a large vertical positional error.

  7. Two-dimensional particle-in-cell plasma source ion implantation of a prolate spheroid target

    International Nuclear Information System (INIS)

    Cheng-Sen, Liu; Hong-Ying, Han; Xiao-Qing, Peng; Ye, Chang; De-Zhen, Wang

    2010-01-01

    A two-dimensional particle-in-cell simulation is used to study the time-dependent evolution of the sheath surrounding a prolate spheroid target during a high voltage pulse in plasma source ion implantation. Our study shows that the potential contour lines pack more closely in the plasma sheath near the vertex of the major axis, i.e. where a thinner sheath is formed, and a non-uniform total ion dose distribution is incident along the surface of the prolate spheroid target due to the focusing of ions by the potential structure. Ion focusing takes place not only at the vertex of the major axis, where dense potential contour lines exist, but also at the vertex of the minor axis, where sparse contour lines exist. This results in two peaks of the received ion dose, locating at the vertices of the major and minor axes of the prolate spheroid target, and an ion dose valley, staying always between the vertices, rather than at the vertex of the minor axis

  8. Two-dimensional particle-in-cell plasma source ion implantation of a prolate spheroid target

    Science.gov (United States)

    Liu, Cheng-Sen; Han, Hong-Ying; Peng, Xiao-Qing; Chang, Ye; Wang, De-Zhen

    2010-03-01

    A two-dimensional particle-in-cell simulation is used to study the time-dependent evolution of the sheath surrounding a prolate spheroid target during a high voltage pulse in plasma source ion implantation. Our study shows that the potential contour lines pack more closely in the plasma sheath near the vertex of the major axis, i.e. where a thinner sheath is formed, and a non-uniform total ion dose distribution is incident along the surface of the prolate spheroid target due to the focusing of ions by the potential structure. Ion focusing takes place not only at the vertex of the major axis, where dense potential contour lines exist, but also at the vertex of the minor axis, where sparse contour lines exist. This results in two peaks of the received ion dose, locating at the vertices of the major and minor axes of the prolate spheroid target, and an ion dose valley, staying always between the vertices, rather than at the vertex of the minor axis.

  9. Two-dimensional evaluation of an ion plasma produced by pulsed lasers extracted by non-parallel collectors

    International Nuclear Information System (INIS)

    Mahdieh, M H; Gavili, A

    2003-01-01

    Two-dimensional hydrodynamics of ion extraction from quasi-neutral plasmas has been calculated numerically for non-parallel ion extractors, and the results compared with those for the parallel case. The ions were assumed to be initially uniform with a very steep density profile at the boundaries, and held between two non-parallel metal plates as cathode and anode with fixed potentials. Experimentally, tunable pulsed lasers through stepwise photo-excitation and photo-ionization or multi-photo-ionization processes can produce such plasma. Poisson's equation was solved simultaneously with the equations of mass and momentum, assuming the Maxwell-Boltzmann distribution for electrons. Ordinary Cartesian co-ordinates are not suitable for the rotated extractor geometry; therefore using the 'algebraic method' a transformation from the physical domain into the computational rectangular plane is applied for analysing the irregular boundaries. Such a technique provides adequate resolution for the boundary layer. Using a first-order explicit upwind differencing in an appropriate transformed Cartesian co-ordinate system, the hydrodynamics of the plasma ions between the two non-parallel electrodes was evaluated. In these calculations electric potential, ion density between the two electrodes, and the extraction time were assessed, considering three separate regions for the plasma, i.e. the ion sheath where (n i >>n e ∼0), the transition region (pre-sheath) (n i = n e ), and the quasi-neutral plasma (n i -n e i ). The results were compared with those for parallel electrodes. A significant discrepancy was found between the two results. From the calculation, the non-uniform asymmetric potential contour, and the ion density contour across the plasma, were obtained for the non-parallel electrodes. For comparison with the parallel extractors, we have also obtained almost the same extraction time for the non-parallel extractors

  10. Dispersion and damping of two-dimensional dust acoustic waves: theory and simulation

    International Nuclear Information System (INIS)

    Upadhyaya, Nitin; Miskovic, Z L; Hou, L-J

    2010-01-01

    A two-dimensional generalized hydrodynamics (GH) model is developed to study the full spectrum of both longitudinal and transverse dust acoustic waves (DAW) in strongly coupled complex (dusty) plasmas, with memory-function-formalism being implemented to enforce high-frequency sum rules. Results are compared with earlier theories (such as quasi-localized charge approximation and its extended version) and with a self-consistent Brownian dynamics simulation. It is found that the GH approach provides a good account, not only of dispersion relations, but also of damping rates of the DAW modes in a wide range of coupling strengths, an issue hitherto not fully addressed for dusty plasmas.

  11. Non-equilibrium phase transitions in complex plasma

    International Nuclear Information System (INIS)

    Suetterlin, K R; Raeth, C; Ivlev, A V; Thomas, H M; Khrapak, S; Zhdanov, S; Rubin-Zuzic, M; Morfill, G E; Wysocki, A; Loewen, H; Goedheer, W J; Fortov, V E; Lipaev, A M; Molotkov, V I; Petrov, O F

    2010-01-01

    Complex plasma being the 'plasma state of soft matter' is especially suitable for investigations of non-equilibrium phase transitions. Non-equilibrium phase transitions can manifest in dissipative structures or self-organization. Two specific examples are lane formation and phase separation. Using the permanent microgravity laboratory PK-3 Plus, operating onboard the International Space Station, we performed unique experiments with binary mixtures of complex plasmas that showed both lane formation and phase separation. These observations have been augmented by comprehensive numerical and theoretical studies. In this paper we present an overview of our most important results. In addition we put our results in context with research of complex plasmas, binary systems and non-equilibrium phase transitions. Necessary and promising future complex plasma experiments on phase separation and lane formation are briefly discussed.

  12. Simulated two-dimensional electronic spectroscopy of the eight-bacteriochlorophyll FMO complex

    Energy Technology Data Exchange (ETDEWEB)

    Yeh, Shu-Hao [Department of Chemistry and Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907 (United States); Kais, Sabre, E-mail: kais@purdue.edu [Department of Chemistry and Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907 (United States); Qatar Environment and Energy Research Institute, Qatar Foundation, Doha (Qatar)

    2014-12-21

    The Fenna-Matthews-Olson (FMO) protein-pigment complex acts as a molecular wire conducting energy between the outer antenna system and the reaction center; it is an important photosynthetic system to study the transfer of excitonic energy. Recent crystallographic studies report the existence of an additional (eighth) bacteriochlorophyll a (BChl a) in some of the FMO monomers. To understand the functionality of this eighth BChl, we simulated the two-dimensional electronic spectra of both the 7-site (apo form) and the 8-site (holo form) variant of the FMO complex from green sulfur bacteria, Prosthecochloris aestuarii. By comparing the spectrum, it was found that the eighth BChl can affect two different excitonic energy transfer pathways: (1) it is directly involved in the first apo form pathway (6 → 3 → 1) by passing the excitonic energy to exciton 6; and (2) it facilitates an increase in the excitonic wave function overlap between excitons 4 and 5 in the second pathway (7 → 4,5 → 2 → 1) and thus increases the possible downward sampling routes across the BChls.

  13. Two-dimensional layer architecture assembled by Keggin polyoxotungstate, Cu(II)-EDTA complex and sodium linker: Synthesis, crystal structures, and magnetic properties

    International Nuclear Information System (INIS)

    Liu Hong; Xu Lin; Gao Guanggang; Li Fengyan; Yang Yanyan; Li Zhikui; Sun Yu

    2007-01-01

    Reaction of Keggin polyoxotungstate with copper(II)-EDTA (EDTA=ethylenediamine tetraacetate) complex under mild conditions led to the formation of hybrid inorganic-organic compounds Na 4 (OH)[(Cu 2 EDTA)PW 12 O 40 ].17H 2 O (1) and Na 4 [(Cu 2 EDTA)SiW 12 O 40 ].19H 2 O (2). The single-crystal X-ray diffraction analyses reveal their two structural features: (1) one-dimensional chain structure consisting of Keggin polyoxotungstate and copper(II)-EDTA complex; (2) Two-dimensional layer architecture assembled by the one-dimensional chain structure and sodium linker. The results of magnetic measurements in the temperature range 300-2 K indicated the existence of ferromagnetic exchange interactions between the Cu II ions for both compounds. In addition, TGA analysis, IR spectra, and electrochemical properties were also investigated to well characterize these two compounds. - Graphical abstract: Two new polyoxometalate-based hybrids, Na 4 (OH)[Cu 2 (EDTA)PW 12 O 40 ].17H 2 O (1) and Na 4 [Cu 2 (EDTA)SiW 12 O 40 ].19H 2 O (2), have been synthesized and structurally characterized, which consist of one-dimensional chain structure assembled by Keggin polyoxotungstate and copper(II)-EDTA complex. The chains are further connected to form two-dimensional layer architecture assembled by the one-dimensional chain structure and sodium linker

  14. One and two dimensional simulations on beat wave acceleration

    International Nuclear Information System (INIS)

    Mori, W.; Joshi, C.; Dawson, J.M.; Forslund, D.W.; Kindel, J.M.

    1984-01-01

    Recently there has been considerable interest in the use of fast-large-amplitude plasma waves as the basis for a high energy particle accelerator. In these schemes, lasers are used to create the plasma wave. To date the few simulation studies on this subject have been limited to one-dimensional, short rise time simulations. Here the authors present results from simulations in which more realistic parameters are used. In addition, they present the first two dimensional simulations on this subject. One dimensional simulations on a 2 1/2-D relativistic electromagnetic particle code, in which only a few cells were used in one direction, on colinear optical mixing are presented. In these simulations the laser rise time, laser intensity, plasma density, plasma temperature and system size were varied. The simulations indicate that the theory of Rosenbluth and Liu is applicable over a wide range of parameters. In addition, simulations with a DC magnetic field are presented in order to study the ''Surfatron'' concept

  15. Image quality assessment using two-dimensional complex mel-cepstrum

    Science.gov (United States)

    Cakir, Serdar; Cetin, A. Enis

    2016-11-01

    Assessment of visual quality plays a crucial role in modeling, implementation, and optimization of image- and video-processing applications. The image quality assessment (IQA) techniques basically extract features from the images to generate objective scores. Feature-based IQA methods generally consist of two complementary phases: (1) feature extraction and (2) feature pooling. For feature extraction in the IQA framework, various algorithms have been used and recently, the two-dimensional (2-D) mel-cepstrum (2-DMC) feature extraction scheme has provided promising results in a feature-based IQA framework. However, the 2-DMC feature extraction scheme completely loses image-phase information that may contain high-frequency characteristics and important structural components of the image. In this work, "2-D complex mel-cepstrum" is proposed for feature extraction in an IQA framework. The method tries to integrate Fourier transform phase information into the 2-DMC, which was shown to be an efficient feature extraction scheme for assessment of image quality. Support vector regression is used for feature pooling that provides mapping between the proposed features and the subjective scores. Experimental results show that the proposed technique obtains promising results for the IQA problem by making use of the image-phase information.

  16. Experimental investigation of two-dimensional critical surface structure, stimulated Raman scattering, and two-plasmon decay instability. Annual report, January 1, 1981-April 30, 1982

    International Nuclear Information System (INIS)

    Wong, A.Y.; Eggleston, D.L.; Tanikawa, T.; Qian, S.J.

    1982-11-01

    Experimental observations of the space and time evolution of resonantly enhanced electrostatic electric fields and plasma density in cylindrical geometry demonstrate the development of two-dimensional caviton structure when an initial density perturbation is imposed on the plasma in the direction perpendicular to the driver field. This two-dimensional structure is observed after the development of profile modification and grows on the ion time scale. The existence of a large azimuthal electric field component is an observational signature of two-dimensional structure. Enhanced electric field maxima are found to be azimuthally correlated with the density minima. Both the density cavities and electric field peaks exhibit increased azimuthal location with the growth of two-dimensional structure. The two-dimensional development exhibits a strong dependence on both perturbation wavenumber and driver power. The related theoretical literature is reviewed and numerical, analytical, and qualitative hybrid models for a driven, two-dimensional, inhomogeneous plasma are presented. Preliminary work is presented in the following additional areas: weak magnetic field effects on critical surface physics, optical measurements of fast electron production, two-dimensional effects in microwave-plasma interactions, Langmuir wave trapping, stimulated Raman scattering and two-plasmon decay instability

  17. Direct Observation of Energy Detrapping in LH1-RC Complex by Two-Dimensional Electronic Spectroscopy.

    Science.gov (United States)

    Ma, Fei; Yu, Long-Jiang; Hendrikx, Ruud; Wang-Otomo, Zheng-Yu; van Grondelle, Rienk

    2017-01-18

    The purple bacterial core light harvesting antenna-reaction center (LH1-RC) complex is the simplest system able to achieve the entire primary function of photosynthesis. During the past decade, a variety of photosynthetic proteins were studied by a powerful technique, two-dimensional electronic spectroscopy (2DES). However, little attention has been paid to LH1-RC, although its reversible uphill energy transfer, trapping, and backward detrapping processes, represent a crucial step in the early photosynthetic reaction dynamics. Thus, in this work, we employed 2DES to study two LH1-RC complexes of Thermochromatium (Tch.) tepidum. By direct observation of detrapping, the complex reversible process was clearly identified and an overall scheme of the excitation evolution in LH1-RC was obtained.

  18. Spectroscopy of charge transfer complexes of four amino acids as organic two-dimensional conductors

    International Nuclear Information System (INIS)

    Padhiyar, Ashvin; Patel, A J; Oza, A T

    2007-01-01

    It is found in this study that four amino acids, namely asparagine, arginine, histidine and glutamine form two-dimensional conducting systems which are charge transfer complexes (CTCs) with organic acceptors like TCNQ, TCNE, chloranil, DDQ, TNF and iodine. It is verified using optical absorption edges that these are 2d conductors like transition metal dichalcogenides obeying absorption functions different from 1d and 3d conductors. This 2d nature is related to the network of intermolecular H-bonding in these complexes, which leads to a global H-bonded network resulting in the absence of local deformation due to the relaxation of strain

  19. Kolmogorov flow in two dimensional strongly coupled dusty plasma

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Akanksha; Ganesh, R., E-mail: ganesh@ipr.res.in; Joy, Ashwin [Institute for Plasma Research, Bhat Gandhinagar, Gujarat 382 428 (India)

    2014-07-15

    Undriven, incompressible Kolmogorov flow in two dimensional doubly periodic strongly coupled dusty plasma is modelled using generalised hydrodynamics, both in linear and nonlinear regime. A complete stability diagram is obtained for low Reynolds numbers R and for a range of viscoelastic relaxation time τ{sub m} [0 < τ{sub m} < 10]. For the system size considered, using a linear stability analysis, similar to Navier Stokes fluid (τ{sub m} = 0), it is found that for Reynolds number beyond a critical R, say R{sub c}, the Kolmogorov flow becomes unstable. Importantly, it is found that R{sub c} is strongly reduced for increasing values of τ{sub m}. A critical τ{sub m}{sup c} is found above which Kolmogorov flow is unconditionally unstable and becomes independent of Reynolds number. For R < R{sub c}, the neutral stability regime found in Navier Stokes fluid (τ{sub m} = 0) is now found to be a damped regime in viscoelastic fluids, thus changing the fundamental nature of transition of Kolmogorov flow as function of Reynolds number R. A new parallelized nonlinear pseudo spectral code has been developed and is benchmarked against eigen values for Kolmogorov flow obtained from linear analysis. Nonlinear states obtained from the pseudo spectral code exhibit cyclicity and pattern formation in vorticity and viscoelastic oscillations in energy.

  20. Influence of the low-frequency source parameters on the plasma characteristics in a dual frequency capacitively coupled plasma reactor: Two dimensional simulations

    Institute of Scientific and Technical Information of China (English)

    Xiang Xu; Hao Ge; Shuai Wang; Zhongling Dai; Younian Wang; Aimin Zhu

    2009-01-01

    A two-dimensional (2D) fluid model is presented to study the discharge of argon in a dual frequency capacitively coupled plasma (CCP) reactor. We are interested in the influence of low-frequency (LF) source parameters such as applied voltage amplitudes and low frequencies on the plasma characteristics. In this paper, the high frequency is set to 60 MHz with voltage 50 V. The simulations were carried out for low frequencies of 1, 2 and 6 MHz with LF voltage 100 V, and for LF voltages of 60, 90 and 120 V with low frequency 2 MHz. The results of 2D distributions of electric field and ion density, the ion flux impinging on the substrate and the ion energy on the powered electrode are shown. As the low frequency increases, two sources become from uncoupling to coupling, When two sources are uncoupling, the increase in LF has little impact on the plasma characteristics, but when two sources are coupling, the increase in LF decreases the uniformities of ion density and ion flux noticeably. It is also found that with the increase in LF voltage, the uniformities in the radial direction of ion density distribution and ion flux at the powered electrode decreases significantly, and the energy of ions bombarding on the powered electrode increases significantly.

  1. Two-and-one-half-dimensional magnetohydrodynamic simulations of the plasma sheet in the presence of oxygen ions: The plasma sheet oscillation and compressional Pc 5 waves

    International Nuclear Information System (INIS)

    Lu Li; Liu Zhenxing; Cao Jinbin

    2002-01-01

    Two-and-one-half-dimensional magnetohydrodynamic simulations of the multicomponent plasma sheet with the velocity curl term in the magnetic equation are represented. The simulation results can be summarized as follows: (1) There is an oscillation of the plasma sheet with the period on the order of 400 s (Pc 5 range); (2) the magnetic equator is a node of the magnetic field disturbance; (3) the magnetic energy integral varies antiphase with the internal energy integral; (4) disturbed waves have a propagating speed on the order of 10 km/s earthward; (5) the abundance of oxygen ions influences amplitude, period, and dissipation of the plasma sheet oscillation. It is suggested that the compressional Pc 5 waves, which are observed in the plasma sheet close to the magnetic equator, may be caused by the plasma sheet oscillation, or may be generated from the resonance of the plasma sheet oscillation with some Pc 5 perturbation waves coming from the outer magnetosphere

  2. Introduction to complex plasmas

    International Nuclear Information System (INIS)

    Bonitz, Michael; Ludwig, Patrick; Horing, Norman

    2010-01-01

    Complex plasmas differ from traditional plasmas in many ways: these are low-temperature high pressure systems containing nanometer to micrometer size particles which may be highly charged and strongly interacting. The particles may be chemically reacting or be in contact with solid surfaces, and the electrons may show quantum behaviour. These interesting properties have led to many applications of complex plasmas in technology, medicine and science. Yet complex plasmas are extremely complicated, both experimentally and theoretically, and require a variety of new approaches which go beyond standard plasma physics courses. This book fills this gap presenting an introduction to theory, experiment and computer simulation in this field. Based on tutorial lectures at a very successful recent Summer Institute, the presentation is ideally suited for graduate students, plasma physicists and experienced undergraduates. (orig.)

  3. Introduction to Complex Plasmas

    CERN Document Server

    Bonitz, Michael; Ludwig, Patrick

    2010-01-01

    Complex plasmas differ from traditional plasmas in many ways: these are low-temperature high pressure systems containing nanometer to micrometer size particles which may be highly charged and strongly interacting. The particles may be chemically reacting or be in contact with solid surfaces, and the electrons may show quantum behaviour. These interesting properties have led to many applications of complex plasmas in technology, medicine and science. Yet complex plasmas are extremely complicated, both experimentally and theoretically, and require a variety of new approaches which go beyond standard plasma physics courses. This book fills this gap presenting an introduction to theory, experiment and computer simulation in this field. Based on tutorial lectures at a very successful recent Summer Institute, the presentation is ideally suited for graduate students, plasma physicists and experienced undergraduates.

  4. Coherent structures in two-dimensional plasma turbulence

    DEFF Research Database (Denmark)

    Huld, T.; Nielsen, A.H.; Pécseli, H.L.

    1991-01-01

    -band turbulent fluctuations is demonstrated by a conditional sampling technique. Depending on plasma parameters, the dominant structures can appear as monopole or multipole vortices, dipole vortices in particular. The importance of large structures for the turbulent plasma diffusion is discussed. A statistical...... analysis of the randomly varying plasma flux is presented....

  5. Two-dimensional simulation of the MHD stability, (1)

    International Nuclear Information System (INIS)

    Kurita, Gen-ichi; Amano, Tsuneo.

    1976-03-01

    The two-dimensional computer code has been prepared to study MHD stability of an axisymmetric toroidal plasma with and without the surrounding vacuum region. It also includes the effect of magnetic surfaces with non-circular cross sections. The linearized equations of motion are solved as an initial value problem. The results by computer simulation are compared with those by the theory for the cylindrical plasma; they are in good agreement. (auth.)

  6. Energy transport in a shear flow of particles in a two-dimensional dusty plasma.

    Science.gov (United States)

    Feng, Yan; Goree, J; Liu, Bin

    2012-11-01

    A shear flow of particles in a laser-driven two-dimensional (2D) dusty plasma is observed in a study of viscous heating and thermal conduction. Video imaging and particle tracking yields particle velocity data, which we convert into continuum data, presented as three spatial profiles: mean particle velocity (i.e., flow velocity), mean-square particle velocity, and mean-square fluctuations of particle velocity. These profiles and their derivatives allow a spatially resolved determination of each term in the energy and momentum continuity equations, which we use for two purposes. First, by balancing these terms so that their sum (i.e., residual) is minimized while varying viscosity η and thermal conductivity κ as free parameters, we simultaneously obtain values for η and κ in the same experiment. Second, by comparing the viscous heating and thermal conduction terms, we obtain a spatially resolved characterization of the viscous heating.

  7. Kinetics of two-dimensional electron plasma, interacting with fluctuating potential

    International Nuclear Information System (INIS)

    Boiko, I.I.; Sirenko, Y.M.

    1990-01-01

    In this paper, from the first principles, after the fashion of Klimontovich, the authors derive quantum kinetic equation for electron gas, inhomogeneous in z-direction and homogeneous in XY-plane. Special attention is given to the systems with quasi-two-dimensional electron gas (2 DEG), which are widely explored now. Both interaction between the particles of 2 DEG (in general, of several sorts), and interaction with an external system (phonons, impurities, after change carries etc.) are considered. General theory is used to obtain energy and momentum balance equations and relaxation frequencies for 2 DEG in the basis of plane waves. The case of crossed electric and magnetic fields is also treated. As an illustration the problems of 2 DEG scattering on semibounded three-dimensional electron gas and on two-dimensional hole gas are considered; transverse conductivity of nondegenerate 2 DEG, scattered by impurities in ultraquantum magnetic field, is calculated

  8. Coupled Langmuir oscillations in 2-dimensional quantum plasmas

    International Nuclear Information System (INIS)

    Akbari-Moghanjoughi, M.

    2014-01-01

    In this work, we present a hydrodynamic model to study the coupled quantum electron plasma oscillations (QEPO) for two dimensional (2D) degenerate plasmas, which incorporates all the essential quantum ingredients such as the statistical degeneracy pressure, electron-exchange, and electron quantum diffraction effect. Effects of diverse physical aspects like the electronic band-dispersion effect, the electron exchange-correlations and the quantum Bohm-potential as well as other important plasma parameters such as the coupling parameter (plasma separation) and the plasma electron number-densities on the linear response of the coupled system are investigated. By studying three different 2D plasma coupling types, namely, graphene-graphene, graphene-metalfilm, and metalfilm-metalfilm coupling configurations, it is remarked that the collective quantum effects can influence the coupled modes quite differently, depending on the type of the plasma configuration. It is also found that the slow and fast QEPO frequency modes respond very differently to the change in plasma parameters. Current findings can help in understanding of the coupled density oscillations in multilayer graphene, graphene-based heterojunctions, or nanofabricated integrated circuits

  9. Observation of Electronic Excitation Transfer Through Light Harvesting Complex II Using Two-Dimensional Electronic-Vibrational Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, NHC; Gruenke, NL; Oliver, TAA; Ballottari, M; Bassi, R; Fleming, GR

    2016-10-05

    Light-harvesting complex II (LHCII) serves a central role in light harvesting for oxygenic photosynthesis and is arguably the most important photosynthetic antenna complex. In this article, we present two-dimensional electronic–vibrational (2DEV) spectra of LHCII isolated from spinach, demonstrating the possibility of using this technique to track the transfer of electronic excitation energy between specific pigments within the complex. We assign the spectral bands via comparison with the 2DEV spectra of the isolated chromophores, chlorophyll a and b, and present evidence that excitation energy between the pigments of the complex are observed in these spectra. Lastly, we analyze the essential components of the 2DEV spectra using singular value decomposition, which makes it possible to reveal the relaxation pathways within this complex.

  10. Probing energy transfer events in the light harvesting complex 2 (LH2) of Rhodobacter sphaeroides with two-dimensional spectroscopy.

    Science.gov (United States)

    Fidler, Andrew F; Singh, Ved P; Long, Phillip D; Dahlberg, Peter D; Engel, Gregory S

    2013-10-21

    Excitation energy transfer events in the photosynthetic light harvesting complex 2 (LH2) of Rhodobacter sphaeroides are investigated with polarization controlled two-dimensional electronic spectroscopy. A spectrally broadened pulse allows simultaneous measurement of the energy transfer within and between the two absorption bands at 800 nm and 850 nm. The phased all-parallel polarization two-dimensional spectra resolve the initial events of energy transfer by separating the intra-band and inter-band relaxation processes across the two-dimensional map. The internal dynamics of the 800 nm region of the spectra are resolved as a cross peak that grows in on an ultrafast time scale, reflecting energy transfer between higher lying excitations of the B850 chromophores into the B800 states. We utilize a polarization sequence designed to highlight the initial excited state dynamics which uncovers an ultrafast transfer component between the two bands that was not observed in the all-parallel polarization data. We attribute the ultrafast transfer component to energy transfer from higher energy exciton states to lower energy states of the strongly coupled B850 chromophores. Connecting the spectroscopic signature to the molecular structure, we reveal multiple relaxation pathways including a cyclic transfer of energy between the two rings of the complex.

  11. Probing energy transfer events in the light harvesting complex 2 (LH2) of Rhodobacter sphaeroides with two-dimensional spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Fidler, Andrew F.; Singh, Ved P.; Engel, Gregory S. [Department of Chemistry, The Institute for Biophysical Dynamics, and The James Franck Institute, The University of Chicago, Chicago, Illinois 60637 (United States); Long, Phillip D.; Dahlberg, Peter D. [Graduate Program in the Biophysical Sciences, The University of Chicago, Chicago, Illinois 60637 (United States)

    2013-10-21

    Excitation energy transfer events in the photosynthetic light harvesting complex 2 (LH2) of Rhodobacter sphaeroides are investigated with polarization controlled two-dimensional electronic spectroscopy. A spectrally broadened pulse allows simultaneous measurement of the energy transfer within and between the two absorption bands at 800 nm and 850 nm. The phased all-parallel polarization two-dimensional spectra resolve the initial events of energy transfer by separating the intra-band and inter-band relaxation processes across the two-dimensional map. The internal dynamics of the 800 nm region of the spectra are resolved as a cross peak that grows in on an ultrafast time scale, reflecting energy transfer between higher lying excitations of the B850 chromophores into the B800 states. We utilize a polarization sequence designed to highlight the initial excited state dynamics which uncovers an ultrafast transfer component between the two bands that was not observed in the all-parallel polarization data. We attribute the ultrafast transfer component to energy transfer from higher energy exciton states to lower energy states of the strongly coupled B850 chromophores. Connecting the spectroscopic signature to the molecular structure, we reveal multiple relaxation pathways including a cyclic transfer of energy between the two rings of the complex.

  12. Probing energy transfer events in the light harvesting complex 2 (LH2) of Rhodobacter sphaeroides with two-dimensional spectroscopy

    International Nuclear Information System (INIS)

    Fidler, Andrew F.; Singh, Ved P.; Engel, Gregory S.; Long, Phillip D.; Dahlberg, Peter D.

    2013-01-01

    Excitation energy transfer events in the photosynthetic light harvesting complex 2 (LH2) of Rhodobacter sphaeroides are investigated with polarization controlled two-dimensional electronic spectroscopy. A spectrally broadened pulse allows simultaneous measurement of the energy transfer within and between the two absorption bands at 800 nm and 850 nm. The phased all-parallel polarization two-dimensional spectra resolve the initial events of energy transfer by separating the intra-band and inter-band relaxation processes across the two-dimensional map. The internal dynamics of the 800 nm region of the spectra are resolved as a cross peak that grows in on an ultrafast time scale, reflecting energy transfer between higher lying excitations of the B850 chromophores into the B800 states. We utilize a polarization sequence designed to highlight the initial excited state dynamics which uncovers an ultrafast transfer component between the two bands that was not observed in the all-parallel polarization data. We attribute the ultrafast transfer component to energy transfer from higher energy exciton states to lower energy states of the strongly coupled B850 chromophores. Connecting the spectroscopic signature to the molecular structure, we reveal multiple relaxation pathways including a cyclic transfer of energy between the two rings of the complex

  13. Development and validation of a comprehensive two-dimensional gas chromatography-mass spectrometry method for the analysis of phytosterol oxidation products in human plasma

    NARCIS (Netherlands)

    Menéndez-Carreño, M.; Steenbergen, H.; Janssen, H.-G.

    2012-01-01

    Phytosterol oxidation products (POPs) have been suggested to exert adverse biological effects similar to, although less severe than, their cholesterol counterparts. For that reason, their analysis in human plasma is highly relevant. Comprehensive two-dimensional gas chromatography (GC×GC) coupled

  14. Two-dimensional gel electrophoresis and FTIR spectroscopy reveal both forms of yeast plasma membrane H(+)-ATPase in activated and basal-level enzyme preparations

    Czech Academy of Sciences Publication Activity Database

    Lapathitis, Georgios; Tanfani, F.; Kotyk, Arnošt; Bertoli, E.

    2001-01-01

    Roč. 505, č. 1 (2001), s. 155-158 ISSN 0014-5793 R&D Projects: GA ČR GA204/98/0474 Keywords : H+-ATPase * plasma membrane * two-dimensional gel electrophoresis Subject RIV: CE - Biochemistry Impact factor: 3.644, year: 2001

  15. Time resolved two- and three-dimensional plasma diagnostics

    International Nuclear Information System (INIS)

    1991-03-01

    This collection of papers on diagnostics in fusion plasmas contains work on the data analysis of inverse problems and on the experimental arrangements presently used to obtain spatially and temporally resolved plasma radial profiles, including electron and ion temperature, plasma density and plasma current profiles. Refs, figs and tabs

  16. Chaotic dynamics in two-dimensional noninvertible maps

    CERN Document Server

    Mira, Christian; Cathala, Jean-Claude; Gardini, Laura

    1996-01-01

    This book is essentially devoted to complex properties (Phase plane structure and bifurcations) of two-dimensional noninvertible maps, i.e. maps having either a non-unique inverse, or no real inverse, according to the plane point. They constitute models of sets of discrete dynamical systems encountered in Engineering (Control, Signal Processing, Electronics), Physics, Economics, Life Sciences. Compared to the studies made in the one-dimensional case, the two-dimensional situation remained a long time in an underdeveloped state. It is only since these last years that the interest for this resea

  17. Three dimensional imaging technique for laser-plasma diagnostics

    International Nuclear Information System (INIS)

    Jiang Shaoen; Zheng Zhijian; Liu Zhongli

    2001-01-01

    A CT technique for laser-plasma diagnostic and a three-dimensional (3D) image reconstruction program (CT3D) have been developed. The 3D images of the laser-plasma are reconstructed by using a multiplication algebraic reconstruction technique (MART) from five pinhole camera images obtained along different sight directions. The technique has been used to measure the three-dimensional distribution of X-ray of laser-plasma experiments in Xingguang II device, and the good results are obtained. This shows that a CT technique can be applied to ICF experiments

  18. Three dimensional imaging technique for laser-plasma diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Shaoen, Jiang; Zhijian, Zheng; Zhongli, Liu [China Academy of Engineering Physics, Chengdu (China)

    2001-04-01

    A CT technique for laser-plasma diagnostic and a three-dimensional (3D) image reconstruction program (CT3D) have been developed. The 3D images of the laser-plasma are reconstructed by using a multiplication algebraic reconstruction technique (MART) from five pinhole camera images obtained along different sight directions. The technique has been used to measure the three-dimensional distribution of X-ray of laser-plasma experiments in Xingguang II device, and the good results are obtained. This shows that a CT technique can be applied to ICF experiments.

  19. Study of the nonlinear three-dimensional Debye screening in plasmas

    International Nuclear Information System (INIS)

    Lin Chang; Zhao Jinbao; Zhang Xiulian

    2000-01-01

    The nonlinear three-dimensional Debye screening in plasmas is investigated. New analytical solutions for the three-dimensional Poisson equation have been obtained for the nonlinear Debye potential for the first time. We derive exact analytical expression for the special case of the nonlinear three-dimensional Debye screening in plasmas. (orig.)

  20. Analogies between random matrix ensembles and the one-component plasma in two-dimensions

    Directory of Open Access Journals (Sweden)

    Peter J. Forrester

    2016-03-01

    Full Text Available The eigenvalue PDF for some well known classes of non-Hermitian random matrices — the complex Ginibre ensemble for example — can be interpreted as the Boltzmann factor for one-component plasma systems in two-dimensional domains. We address this theme in a systematic fashion, identifying the plasma system for the Ginibre ensemble of non-Hermitian Gaussian random matrices G, the spherical ensemble of the product of an inverse Ginibre matrix and a Ginibre matrix G1−1G2, and the ensemble formed by truncating unitary matrices, as well as for products of such matrices. We do this when each has either real, complex or real quaternion elements. One consequence of this analogy is that the leading form of the eigenvalue density follows as a corollary. Another is that the eigenvalue correlations must obey sum rules known to characterise the plasma system, and this leads us to an exhibit of an integral identity satisfied by the two-particle correlation for real quaternion matrices in the neighbourhood of the real axis. Further random matrix ensembles investigated from this viewpoint are self dual non-Hermitian matrices, in which a previous study has related to the one-component plasma system in a disk at inverse temperature β=4, and the ensemble formed by the single row and column of quaternion elements from a member of the circular symplectic ensemble.

  1. Two dimensional PMMA nanofluidic device fabricated by hot embossing and oxygen plasma assisted thermal bonding methods

    Science.gov (United States)

    Yin, Zhifu; Sun, Lei; Zou, Helin; Cheng, E.

    2015-05-01

    A method for obtaining a low-cost and high-replication precision two-dimensional (2D) nanofluidic device with a polymethyl methacrylate (PMMA) sheet is proposed. To improve the replication precision of the 2D PMMA nanochannels during the hot embossing process, the deformation of the PMMA sheet was analyzed by a numerical simulation method. The constants of the generalized Maxwell model used in the numerical simulation were calculated by experimental compressive creep curves based on previously established fitting formula. With optimized process parameters, 176 nm-wide and 180 nm-deep nanochannels were successfully replicated into the PMMA sheet with a replication precision of 98.2%. To thermal bond the 2D PMMA nanochannels with high bonding strength and low dimensional loss, the parameters of the oxygen plasma treatment and thermal bonding process were optimized. In order to measure the dimensional loss of 2D nanochannels after thermal bonding, a dimension loss evaluating method based on the nanoindentation experiments was proposed. According to the dimension loss evaluating method, the total dimensional loss of 2D nanochannels was 6 nm and 21 nm in width and depth, respectively. The tensile bonding strength of the 2D PMMA nanofluidic device was 0.57 MPa. The fluorescence images demonstrate that there was no blocking or leakage over the entire microchannels and nanochannels.

  2. Statistical properties of three-dimensional two-fluid plasma model

    Energy Technology Data Exchange (ETDEWEB)

    Qaisrani, M. Hasnain [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, WuHan, Hubei 430074 (China); Xia, ZhenWei [Department of Modern Physics, University of Science and Technology of China, Hefei 230026 (China); Zou, Dandan, E-mail: ddzou@hust.edu.cn [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, WuHan, Hubei 430074 (China); School of Physics and Optoelectronic Engineering, Yangtze University, Jingzhou 434023 (China)

    2015-09-15

    The nonlinear dynamics of incompressible non-dissipative two-fluid plasma model is investigated through classical Gibbs ensemble methods. Liouville's theorem of phase space for each wave number is proved, and the absolute equilibrium spectra for Galerkin truncated two-fluid model are calculated. In two-fluid theory, the equilibrium is built on the conservation of three quadratic invariants: the total energy and the self-helicities for ions and electrons fluid, respectively. The implications of statistic equilibrium spectra with arbitrary ratios of conserved invariants are discussed.

  3. Two-dimensional multifractal cross-correlation analysis

    International Nuclear Information System (INIS)

    Xi, Caiping; Zhang, Shuning; Xiong, Gang; Zhao, Huichang; Yang, Yonghong

    2017-01-01

    Highlights: • We study the mathematical models of 2D-MFXPF, 2D-MFXDFA and 2D-MFXDMA. • Present the definition of the two-dimensional N 2 -partitioned multiplicative cascading process. • Do the comparative analysis of 2D-MC by 2D-MFXPF, 2D-MFXDFA and 2D-MFXDMA. • Provide a reference on the choice and parameter settings of these methods in practice. - Abstract: There are a number of situations in which several signals are simultaneously recorded in complex systems, which exhibit long-term power-law cross-correlations. This paper presents two-dimensional multifractal cross-correlation analysis based on the partition function (2D-MFXPF), two-dimensional multifractal cross-correlation analysis based on the detrended fluctuation analysis (2D-MFXDFA) and two-dimensional multifractal cross-correlation analysis based on the detrended moving average analysis (2D-MFXDMA). We apply these methods to pairs of two-dimensional multiplicative cascades (2D-MC) to do a comparative study. Then, we apply the two-dimensional multifractal cross-correlation analysis based on the detrended fluctuation analysis (2D-MFXDFA) to real images and unveil intriguing multifractality in the cross correlations of the material structures. At last, we give the main conclusions and provide a valuable reference on how to choose the multifractal algorithms in the potential applications in the field of SAR image classification and detection.

  4. Tunable all-angle negative refraction and photonic band gaps in two-dimensional plasma photonic crystals with square-like Archimedean lattices

    International Nuclear Information System (INIS)

    Zhang, Hai-Feng; Liu, Shao-Bin; Jiang, Yu-Chi

    2014-01-01

    In this paper, the tunable all-angle negative refraction and photonic band gaps (PBGs) in two types of two-dimensional (2D) plasma photonic crystals (PPCs) composed of homogeneous plasma and dielectric (GaAs) with square-like Archimedean lattices (ladybug and bathroom lattices) for TM wave are theoretically investigated based on a modified plane wave expansion method. The type-1 structure is dielectric rods immersed in the plasma background, and the complementary structure is named as type-2 PPCs. Theoretical simulations demonstrate that the both types of PPCs with square-like Archimedean lattices have some advantages in obtaining the higher cut-off frequency, the larger PBGs, more number of PBGs, and the relative bandwidths compared to the conventional square lattices as the filling factor or radius of inserted rods is same. The influences of plasma frequency and radius of inserted rod on the properties of PBGs for both types of PPCs also are discussed in detail. The calculated results show that PBGs can be manipulated by the parameters as mentioned above. The possibilities of all-angle negative refraction in such two types of PPCs at low bands also are discussed. Our calculations reveal that the all-angle negative phenomena can be observed in the first two TM bands, and the frequency range of all-angle negative refraction can be tuned by changing plasma frequency. Those properties can be used to design the optical switching and sensor

  5. Two-dimensional boundary-value problem for ion-ion diffusion

    International Nuclear Information System (INIS)

    Tuszewski, M.; Lichtenberg, A.J.

    1977-01-01

    Like-particle diffusion is usually negligible compared with unlike-particle diffusion because it is two orders higher in spatial derivatives. When the ratio of the ion gyroradius to the plasma transverse dimension is of the order of the fourth root of the mass ratio, previous one-dimensional analysis indicated that like-particle diffusion is significant. A two-dimensional boundary-value problem for ion-ion diffusion is investigated. Numerical solutions are found with models for which the nonlinear partial differential equation reduces to an ordinary fourth-order differential equation. These solutions indicate that the ion-ion losses are higher by a factor of six for a slab geometry, and by a factor of four for circular geometry, than estimated from dimensional analysis. The solutions are applied to a multiple mirror experiment stabilized with a quadrupole magnetic field which generates highly elliptical flux surfaces. It is found that the ion-ion losses dominate the electron-ion losses and that these classical radial losses contribute to a significant decrease of plasma lifetime, in qualitiative agreement with the experimental results

  6. Isolation of a new two-dimensional honeycomb carbonato-bridged copper(II) complex exhibiting long-range ferromagnetic ordering.

    Science.gov (United States)

    Majumder, Arpi; Choudhury, Chirantan Roy; Mitra, Samiran; Rosair, Georgina M; El Fallah, M Salah; Ribas, Joan

    2005-04-28

    Atmospheric CO2 fixation by an aqueous solution containing Cu(ClO4)2.6H2O and 4-aminopyridine (4-apy) yields a novel example of a two-dimensional mu3-CO3 bridged copper(II) complex {[Cu(4-apy)2]3(mu3-CO3)2(ClO4)2.(1/2)CH3OH}n that has been characterized by IR, UV and X-ray crystallography; preliminary magnetic measurements show that complex exhibits long-range ordered ferromagnetic coupling.

  7. Equidistance of the complex two-dimensional anharmonic oscillator spectrum: the exact solution

    International Nuclear Information System (INIS)

    Cannata, F; Ioffe, M V; Nishnianidze, D N

    2012-01-01

    We study a class of quantum two-dimensional models with complex potentials of a specific form. They can be considered as the generalization of a recently studied model with quadratic interaction not amenable to the conventional separation of variables. In the present case, the property of shape invariance provides the equidistant form of the spectrum and the algorithm to construct eigenfunctions analytically. It is shown that the Hamiltonian is non-diagonalizable, and the resolution of identity must also include the corresponding associated functions. In the specific case of anharmonic second plus fourth-order interaction, expressions for the wavefunctions and associated functions are constructed explicitly for the lowest levels, and the recursive algorithm to produce higher level wavefunctions is given. (paper)

  8. Complex Modified Hybrid Projective Synchronization of Different Dimensional Fractional-Order Complex Chaos and Real Hyper-Chaos

    Directory of Open Access Journals (Sweden)

    Jian Liu

    2014-11-01

    Full Text Available This paper introduces a type of modified hybrid projective synchronization with complex transformationmatrix (CMHPS for different dimensional fractional-order complex chaos and fractional-order real hyper-chaos. The transformationmatrix in this type of chaotic synchronization is a non-square matrix, and its elements are complex numbers. Based on the stability theory of fractional-order systems, by employing the feedback control technique, necessary and sufficient criteria on CMHPS are derived. Furthermore, CMHPS between fractional-order real hyper-chaotic Rössler system and other two different dimensional fractional-order complex Lorenz-like chaotic systems is provided as two examples to discuss reduced order and increased order synchronization, respectively.

  9. One-dimensional plasma simulation studies

    International Nuclear Information System (INIS)

    Friberg, Ari; Virtamo, Jorma

    1976-01-01

    Some basic plasma phenomena are studied by a one-dimensional electrostatic simulation code. A brief description of the code and its application to a test problem is given. The experiments carried out include Landau damping of an excited wave, particle retardation by smoothed field and beam-plasma instability. In each case, the set-up of the experiment is described and the results are compared with theoretical predictions. In the theoretical discussions, the oscillatory behaviour found in the Landau damping experiment is explained, an explicit formula for the particle retardation rate is derived and a rudimentary picture of the beam-plasma instability in terms of quasilinear theory is given. (author)

  10. Two-dimensional imaging of edge plasma electron density and temperature by the passive helium emission ratio technique in TJ-II

    International Nuclear Information System (INIS)

    De la Cal, E; Guasp, J

    2011-01-01

    An intensified visible camera looks tangentially at a poloidal limiter where helium recycles, acting as a wide neutral source, and the atomic line emission due to plasma excitation becomes strongly localized there. It includes a bifurcated coherent bundle, each end with a different interference filter to select helium atomic lines, so that two simultaneous filtered images are captured in one single frame. The object of the proposed technique is to apply the well-known helium-beam line-ratio technique to obtain from selected filtered images the two-dimensional (2D) edge plasma n e and T e . The code EIRENE was used to demonstrate that the helium emission from recycling neutrals dominates the emission for the lines of view passing close above the limiter. Since these chords are nearly parallel to magnetic field lines in the emission region, the images can be approximated to poloidal cuts of the plasma emission within the tolerances discussed in the paper. The absolute radial profiles of T e and n e obtained with the method presented here were checked in the TJ-II stellarator to be in relatively good agreement with other diagnostics within a wide range of plasma parameters for both ECRH and NBI plasmas. The method is finally used to get 2D images of edge plasma T e and n e .

  11. Simulation of the formation of two-dimensional Coulomb liquids and solids in dusty plasmas

    International Nuclear Information System (INIS)

    Hwang, H.H.; Kushner, M.J.

    1997-01-01

    Dust particle transport in low-temperature plasmas has recently received considerable attention due to the desire to minimize contamination of wafers during plasma processing of microelectronics devices. Laser light scattering observations of dust particles near wafers in reactive-ion-etching (RIE) radio frequency (rf) discharges have revealed clouds which display collective behavior. These observations have motivated experimental studies of the Coulomb liquid and solid properties of these systems. In this paper, we present results from a two-dimensional model for dust particle transport in RIE rf discharges in which we include particle-particle Coulomb interactions. We predict the formation of Coulomb liquids and solids. These predictions are based both on values of Γ>2 (liquid) and Γ>170 (solid), where Γ is the ratio of electrostatic potential energy to thermal energy, and on crystal-like structure in the pair correlation function. We find that Coulomb liquids and solids composed of trapped dust particles in RIE discharges are preferentially formed with increasing gas pressure, decreasing particle size, and decreasing rf power. We also observe the ejection of particles from dust crystals which completely fill trapping sites, as well as lattice disordering followed by annealing and refreezing. copyright 1997 American Institute of Physics

  12. Characterization of lipids in complex samples using comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry

    NARCIS (Netherlands)

    Jover, E.; Adahchour, M.; Bayona, J.M.; Vreuls, R.J.J.; Brinkman, U.A.T.

    2005-01-01

    Most lipids are a complex mixture of classes of compounds such as fatty acids, fatty alcohols, diols, sterols and hydroxy acids. In this study, the suitability of comprehensive two-dimensional gas chromatography coupled to a time-of-light mass spectrometer is studied for lipid characterization in

  13. Two-dimensional ion effects in relativistic diodes

    International Nuclear Information System (INIS)

    Poukey, J.W.

    1975-01-01

    In relativistic diodes, ions are emitted from the anode plasma. The effects and properties of these ions are studied via a two-dimensional particle simulation code. The space charge of these ions enhances the electron emission, and this additional current (including that of the ions, themselves) aids in obtaining superpinched electron beams for use in pellet fusion studies. (U.S.)

  14. Activating basal-plane catalytic activity of two-dimensional MoS2 monolayer with remote hydrogen plasma

    KAUST Repository

    Cheng, Chia-Chin

    2016-09-10

    Two-dimensional layered transition metal dichalcogenide (TMD) materials such as Molybdenum disufide (MoS2) have been recognized as one of the low-cost and efficient electrocatalysts for hydrogen evolution reaction (HER). The crystal edges that account for a small percentage of the surface area, rather than the basal planes, of MoS2 monolayer have been confirmed as their active catalytic sites. As a result, extensive efforts have been developing in activating the basal planes of MoS2 for enhancing their HER activity. Here, we report a simple and efficient approach-using a remote hydrogen-plasma process-to creating S-vacancies on the basal plane of monolayer crystalline MoS2; this process can generate high density of S-vacancies while mainly maintaining the morphology and structure of MoS2 monolayer. The density of S-vacancies (defects) on MoS2 monolayers resulted from the remote hydrogen-plasma process can be tuned and play a critical role in HER, as evidenced in the results of our spectroscopic and electrical measurements. The H2-plasma treated MoS2 also provides an excellent platform for systematic and fundamental study of defect-property relationships in TMDs, which provides insights for future applications including electrical, optical and magnetic devices. © 2016 Elsevier Ltd.

  15. Solitary wave solutions of two-dimensional nonlinear Kadomtsev ...

    Indian Academy of Sciences (India)

    Aly R Seadawy

    2017-09-13

    Sep 13, 2017 ... We considered the two-dimensional DASWs in colli- sionless, unmagnetized cold plasma consisting of dust fluid, ions and electrons. The dynamics of DASWs is governed by the normalized fluid equations of nonlin- ear continuity (1), nonlinear motion of system (2) and. (3) and linear Poisson equation (4) as.

  16. Plasma kinetics of Ar/O2 magnetron discharge by two-dimensional multifluid modeling

    International Nuclear Information System (INIS)

    Costin, C.; Minea, T. M.; Popa, G.; Gousset, G.

    2010-01-01

    Multifluid two-dimensional model was developed to describe the plasma kinetics of the direct current Ar/O 2 magnetron, coupling two modules: charged particles and neutrals. The first module deals with three positive ions - Ar + , O 2 + , and O + - and two negative species - e - and O - - treated by the moments of Boltzmann's equation. The second one follows seven neutral species (Ar, O 2 , O, O 3 , and related metastables) by the multicomponent diffusion technique. The two modules are self-consistently coupled by the mass conservation and kinetic coefficients taking into account more than 100 volume reactions. The steady state is obtained when the overall convergence is achieved. Calculations for 10%O 2 in Ar/O 2 mixture at 2.67 and 4 Pa show that the oxygen excited species are mainly created by electron collisions in the negative glow of the discharge. Decreasing the pressure down to 0.67 Pa, the model reveals the nonlocal behavior of the reactive species. The density gradient of O 2 ground state is reversed with respect to all gradients of the other reactive species, since the latter ones originate from the molecular ground state of oxygen. It is also found that the wall reactions drastically modify the space gradient of neutral reactive species, at least as much as the pressure, even if the discharge operates in compound mode.

  17. Two-dimensional simulation of sintering process

    International Nuclear Information System (INIS)

    Vasconcelos, Vanderley de; Pinto, Lucio Carlos Martins; Vasconcelos, Wander L.

    1996-01-01

    The results of two-dimensional simulations are directly applied to systems in which one of the dimensions is much smaller than the others, and to sections of three dimensional models. Moreover, these simulations are the first step of the analysis of more complex three-dimensional systems. In this work, two basic features of the sintering process are studied: the types of particle size distributions related to the powder production processes and the evolution of geometric parameters of the resultant microstructures during the solid-state sintering. Random packing of equal spheres is considered in the sintering simulation. The packing algorithm does not take into account the interactive forces between the particles. The used sintering algorithm causes the densification of the particle set. (author)

  18. Two-dimensional spatial survey of the plasma potential and electric field in a pulsed bipolar magnetron discharge

    International Nuclear Information System (INIS)

    Vetushka, A.; Karkari, S.K.; Bradley, J.W.

    2004-01-01

    Emissive and Langmuir probe techniques have been used to obtain two-dimensional (2D) spatial maps of the plasma potential V p , electric field E, and ion trajectories in a pulsed bipolar magnetron discharge. The magnetron was pulsed at a frequency of 100 kHz, with a 50% duty cycle and operated at an argon pressure of 0.74 Pa. The pulse wave form was characterized by three distinct phases: the 'overshoot', 'reverse', and 'on' phases. In the 'on' phase of the pulse, when the cathode voltage is driven to -670 V, the 2D spatial distribution of V p has a similar form to that in dc magnetron, with significant axial and radial electric fields in the bulk plasma, accelerating ions to the sheath edge above the cathode racetrack region. During the 'overshoot' phase (duration 200 ns), V p is raised to values greater than +330 V, more than 100 V above the cathode potential, with E pointing away from the target. In the 'reverse' phase V p has a value of +45 V at all measured positions, 2 V more positive than the target potential. In this phase there is no electric field present in the plasma. In the bulk of the plasma, the results from Langmuir probe and the emissive probe are in good agreement, however, in one particular region of the plasma outside the radius of the cathode, the emissive probe measurements are consistently more positive (up to 45 V in the 'on' time). This discrepancy is discussed in terms of the different frequency response of the probes and their perturbation of the plasma. A simple circuit model of the plasma-probe system has been proposed to explain our results. A brief discussion of the effect of the changing plasma potential distribution on the operation of the magnetron is given

  19. A computationally exact method of Dawson's model for hole dynamics of one-dimensional plasma

    International Nuclear Information System (INIS)

    Kitahara, Kazuo; Tanno, Kohki; Takada, Toshio; Hatori, Tadatsugu; Urata, Kazuhiro; Irie, Haruyuki; Nambu, Mitsuhiro; Saeki, Kohichi.

    1990-01-01

    We show a simple but computationally exact solution of the one-dimensional plasma model, so-called 'Dawson's model'. Using this solution, we can describe the evolution of the plasma and find the relative stabilization of a big hole after the instability of two streams. (author)

  20. Two dimensional crystals of LH2 light-harvesting complexes from Ectothiorhodospira sp. and Rhodobacter capsulatus investigated by electron microscopy

    NARCIS (Netherlands)

    Oling, Frank; Boekema, EJ; deZarate, IO; Visschers, R; vanGrondelle, R; Keegstra, W; Brisson, A; Picorel, R

    1996-01-01

    Two-dimensional crystals of LH2 (B800-850) light-harvesting complexes from Ectothiorhodospira sp, and Rhodobacter capsulatus were obtained by reconstitution of purified protein into phospholipid vesicles and characterized by electron microscopy. The size of the crystals was up to several

  1. Two-dimensional crystals of LH2 light-harvesting complexes from Ectothiorhodospira sp. and Rhodobacter capsulatus investigated by electron microscopy.

    NARCIS (Netherlands)

    Oling, F.; Boekema, E.J.; Ortiz de Zarate, I.; Visschers, R.W.; van Grondelle, R.; Keegstra, W.; Brisson, A.; Picorel, R.

    1996-01-01

    Two-dimensional crystals of LH2 (B800-850) light-harvesting complexes from Ectothiorhodospira sp. and Rhodobacter capsulatus were obtained by reconstitution of purified protein into phospholipid vesicles and characterized by electron microscopy. The size of the crystals was up to several

  2. Polygon construction to investigate melting in two-dimensional strongly coupled dusty plasma

    International Nuclear Information System (INIS)

    Ruhunusiri, W. D. Suranga; Goree, J.; Feng Yan; Liu Bin

    2011-01-01

    The polygon construction method of Glaser and Clark is used to characterize melting and crystallization in a two-dimensional (2D) strongly coupled dusty plasma. Using particle positions measured by video microscopy, bonds are identified by triangulation, and unusually long bonds are deleted. The resulting polygons have three or more sides. Geometrical defects, which are polygons with more than three sides, are found to proliferate during melting. Pentagons are found in liquids, where they tend to cluster with other pentagons. Quadrilaterals are a less severe defect, so that disorder can be characterized by the ratio of quadrilaterals to pentagons. This ratio is found to be less in a liquid than in a solid or a superheated solid. Another measure of disorder is the abundance of different kinds of vertices, according to the type of polygons that adjoin there. Unexpectedly, spikes are observed in the abundance of certain vertex types during rapid temperature changes. Hysteresis, revealed by a plot of a disorder parameter vs temperature, is examined to study sudden heating. The hysteresis diagram also reveals features suggesting a possibility of latent heat in the melting and rapid cooling processes.

  3. A two-temperature chemical non-equilibrium modeling of DC arc plasma

    International Nuclear Information System (INIS)

    Qian Haiyang; Wu Bin

    2011-01-01

    To a better understanding of non-equilibrium characteristics of DC arc plasma,a two-dimensional axisymmetric two-temperature chemical non-equilibrium (2T-NCE) model is applied for direct current arc argon plasma generator with water-cooled constrictor at atmospheric pressure. The results show that the electron temperature and heavy particle temperature has a relationship under different working parameters, indicating that DC arc plasma has a strong non-equilibrium characteristic, and the variation is obvious. (authors)

  4. High-speed three-dimensional plasma temperature determination of axially symmetric free-burning arcs

    International Nuclear Information System (INIS)

    Bachmann, B; Ekkert, K; Bachmann, J-P; Marques, J-L; Schein, J; Kozakov, R; Gött, G; Schöpp, H; Uhrlandt, D

    2013-01-01

    In this paper we introduce an experimental technique that allows for high-speed, three-dimensional determination of electron density and temperature in axially symmetric free-burning arcs. Optical filters with narrow spectral bands of 487.5–488.5 nm and 689–699 nm are utilized to gain two-dimensional spectral information of a free-burning argon tungsten inert gas arc. A setup of mirrors allows one to image identical arc sections of the two spectral bands onto a single camera chip. Two-different Abel inversion algorithms have been developed to reconstruct the original radial distribution of emission coefficients detected with each spectral window and to confirm the results. With the assumption of local thermodynamic equilibrium we calculate emission coefficients as a function of temperature by application of the Saha equation, the ideal gas law, the quasineutral gas condition and the NIST compilation of spectral lines. Ratios of calculated emission coefficients are compared with measured ones yielding local plasma temperatures. In the case of axial symmetry the three-dimensional plasma temperature distributions have been determined at dc currents of 100, 125, 150 and 200 A yielding temperatures up to 20000 K in the hot cathode region. These measurements have been validated by four different techniques utilizing a high-resolution spectrometer at different positions in the plasma. Plasma temperatures show good agreement throughout the different methods. Additionally spatially resolved transient plasma temperatures have been measured of a dc pulsed process employing a high-speed frame rate of 33000 frames per second showing the modulation of the arc isothermals with time and providing information about the sensitivity of the experimental approach. (paper)

  5. Quantitative evaluation and modeling of two-dimensional neovascular network complexity: the surface fractal dimension

    International Nuclear Information System (INIS)

    Grizzi, Fabio; Russo, Carlo; Colombo, Piergiuseppe; Franceschini, Barbara; Frezza, Eldo E; Cobos, Everardo; Chiriva-Internati, Maurizio

    2005-01-01

    Modeling the complex development and growth of tumor angiogenesis using mathematics and biological data is a burgeoning area of cancer research. Architectural complexity is the main feature of every anatomical system, including organs, tissues, cells and sub-cellular entities. The vascular system is a complex network whose geometrical characteristics cannot be properly defined using the principles of Euclidean geometry, which is only capable of interpreting regular and smooth objects that are almost impossible to find in Nature. However, fractal geometry is a more powerful means of quantifying the spatial complexity of real objects. This paper introduces the surface fractal dimension (D s ) as a numerical index of the two-dimensional (2-D) geometrical complexity of tumor vascular networks, and their behavior during computer-simulated changes in vessel density and distribution. We show that D s significantly depends on the number of vessels and their pattern of distribution. This demonstrates that the quantitative evaluation of the 2-D geometrical complexity of tumor vascular systems can be useful not only to measure its complex architecture, but also to model its development and growth. Studying the fractal properties of neovascularity induces reflections upon the real significance of the complex form of branched anatomical structures, in an attempt to define more appropriate methods of describing them quantitatively. This knowledge can be used to predict the aggressiveness of malignant tumors and design compounds that can halt the process of angiogenesis and influence tumor growth

  6. Parallel and Multivalued Logic by the Two-Dimensional Photon-Echo Response of a Rhodamine–DNA Complex

    Science.gov (United States)

    2015-01-01

    Implementing parallel and multivalued logic operations at the molecular scale has the potential to improve the miniaturization and efficiency of a new generation of nanoscale computing devices. Two-dimensional photon-echo spectroscopy is capable of resolving dynamical pathways on electronic and vibrational molecular states. We experimentally demonstrate the implementation of molecular decision trees, logic operations where all possible values of inputs are processed in parallel and the outputs are read simultaneously, by probing the laser-induced dynamics of populations and coherences in a rhodamine dye mounted on a short DNA duplex. The inputs are provided by the bilinear interactions between the molecule and the laser pulses, and the output values are read from the two-dimensional molecular response at specific frequencies. Our results highlights how ultrafast dynamics between multiple molecular states induced by light–matter interactions can be used as an advantage for performing complex logic operations in parallel, operations that are faster than electrical switching. PMID:25984269

  7. Complex (dusty) plasmas: Current status, open issues, perspectives

    International Nuclear Information System (INIS)

    Fortov, V.E.; Ivlev, A.V.; Khrapak, S.A.; Khrapak, A.G.; Morfill, G.E.

    2005-01-01

    The field of complex (dusty) plasmas-low-temperature plasmas containing charged microparticles-is reviewed: The major types of experimental complex plasmas are briefly discussed. Various elementary processes, including grain charging in different regimes, interaction between charged particles, and momentum exchange between different species are investigated. The major forces on microparticles and features of the particle dynamics in complex plasmas are highlighted. An overview of the wave properties in different phase states, as well as recent results on the phase transitions between different crystalline and liquid states are presented. Fluid behaviour of complex plasmas and the onset of cooperative phenomena are discussed. Properties of the magnetized complex plasmas and plasmas with nonspherical particles are briefly mentioned. In conclusion, possible applications of complex plasmas, interdisciplinary aspects, and perspectives are discussed

  8. Application of stereoscopic particle image velocimetry to studies of transport in a dusty (complex) plasma

    International Nuclear Information System (INIS)

    Thomas, Edward Jr.; Williams, Jeremiah D.; Silver, Jennifer

    2004-01-01

    Over the past 5 years, two-dimensional particle image velocimetry (PIV) techniques [E. Thomas, Jr., Phys. Plasmas 6, 2672 (1999)] have been used to obtain detailed measurements of microparticle transport in dusty plasmas. This Letter reports on an extension of these techniques to a three-dimensional velocity vector measurement approach using stereoscopic PIV. Initial measurements using the stereoscopic PIV diagnostic are presented

  9. Transverse two-stream instability in a matched plasma channel

    International Nuclear Information System (INIS)

    Whlttum, D.H.

    1994-01-01

    A relativistic electron beam magnetically self-focused in a plasma is subject to a transverse two stream or 'hose' instability. Linear evolution is described in terms of a tune distribution characterizing the beam, and an effective transverse impedance determined by the beam and the plasma profiles. This model is compared to cloud-in-cell simulations of three-dimensional transport of a beam with a Bennett profile, through a matched plasma channel. In the limit of large skin-depth this instability appears to be the primary limitation on stable beam transport. (author)

  10. A two-dimensional transport-problem in magnetized plasmas

    International Nuclear Information System (INIS)

    Sigmar, D.J.; Adam, G.; Hittmair, O.

    1975-01-01

    It is shown that by a generalization of the classical theory for a cylindrical plasma the expression for the so-called banana-diffusion in a toroidal plasma may be deduced. The ratio of the coefficient of the banana-diffusion to the one of classical diffusion is discussed. (Auth.)

  11. Optimizing separations in online comprehensive two-dimensional liquid chromatography.

    Science.gov (United States)

    Pirok, Bob W J; Gargano, Andrea F G; Schoenmakers, Peter J

    2018-01-01

    Online comprehensive two-dimensional liquid chromatography has become an attractive option for the analysis of complex nonvolatile samples found in various fields (e.g. environmental studies, food, life, and polymer sciences). Two-dimensional liquid chromatography complements the highly popular hyphenated systems that combine liquid chromatography with mass spectrometry. Two-dimensional liquid chromatography is also applied to the analysis of samples that are not compatible with mass spectrometry (e.g. high-molecular-weight polymers), providing important information on the distribution of the sample components along chemical dimensions (molecular weight, charge, lipophilicity, stereochemistry, etc.). Also, in comparison with conventional one-dimensional liquid chromatography, two-dimensional liquid chromatography provides a greater separation power (peak capacity). Because of the additional selectivity and higher peak capacity, the combination of two-dimensional liquid chromatography with mass spectrometry allows for simpler mixtures of compounds to be introduced in the ion source at any given time, improving quantitative analysis by reducing matrix effects. In this review, we summarize the rationale and principles of two-dimensional liquid chromatography experiments, describe advantages and disadvantages of combining different selectivities and discuss strategies to improve the quality of two-dimensional liquid chromatography separations. © 2017 The Authors. Journal of Separation Science published by WILEY-VCH Verlag GmbH & Co. KGaA.

  12. The design of two color interferometer system for the 3-dimensional analysis of plasma density evolution on KSTAR

    Energy Technology Data Exchange (ETDEWEB)

    Lee, K.C., E-mail: kclee@nfri.re.kr [National Fusion Research Institute, Daejeon 34133 (Korea, Republic of); Juhn, J.-W.; Nam, Y.U.; Kim, Y.S.; Wi, H.M. [National Fusion Research Institute, Daejeon 34133 (Korea, Republic of); Kim, S.W.; Ghim, Y.-C. [Korea Advanced Institute of Science and Technology, Daejeon 34141 (Korea, Republic of)

    2016-12-15

    Highlights: • A Two Color Interferometer (TCI) system is designed for 3-D measurement of KSTAR. • TCI is consists of 10.6 μm CO2 laser and 0.63 μm HeNe laser with tangential 5 channels. • 2 channels are installed in 2016 and 5 channel operation is planned in 2017. - Abstract: A 5-channel two color interferometer (TCI) system has been designed on KSTAR. TCI system is designed for tangential beam paths, which will combine with two existing interferometer systems of vertical and radial beam paths, so that it will provide 3-dimensional measurement of electron density evolution. TCI system uses wavelengths of 10.6 μm by a CO{sub 2} laser and 0.633 μm by a HeNe laser. The system compensates the vibrational noise by using two colors and avoids refraction by short wavelengths. The main purpose of the TCI is to generate routine measurement of the line integrated plasma density for the real time density control on KSTAR. The 5-channels will provide profile data for the density. Time resolution of the system is expected to be 500 kHz or higher in order to measure 3-dimensional density fluctuations for ELMs and other MHD activities including TAE modes. The system is planned to be working on KSTAR 2016 campaign with 1–2 channels.

  13. The design of two color interferometer system for the 3-dimensional analysis of plasma density evolution on KSTAR

    International Nuclear Information System (INIS)

    Lee, K.C.; Juhn, J.-W.; Nam, Y.U.; Kim, Y.S.; Wi, H.M.; Kim, S.W.; Ghim, Y.-C.

    2016-01-01

    Highlights: • A Two Color Interferometer (TCI) system is designed for 3-D measurement of KSTAR. • TCI is consists of 10.6 μm CO2 laser and 0.63 μm HeNe laser with tangential 5 channels. • 2 channels are installed in 2016 and 5 channel operation is planned in 2017. - Abstract: A 5-channel two color interferometer (TCI) system has been designed on KSTAR. TCI system is designed for tangential beam paths, which will combine with two existing interferometer systems of vertical and radial beam paths, so that it will provide 3-dimensional measurement of electron density evolution. TCI system uses wavelengths of 10.6 μm by a CO 2 laser and 0.633 μm by a HeNe laser. The system compensates the vibrational noise by using two colors and avoids refraction by short wavelengths. The main purpose of the TCI is to generate routine measurement of the line integrated plasma density for the real time density control on KSTAR. The 5-channels will provide profile data for the density. Time resolution of the system is expected to be 500 kHz or higher in order to measure 3-dimensional density fluctuations for ELMs and other MHD activities including TAE modes. The system is planned to be working on KSTAR 2016 campaign with 1–2 channels.

  14. Three dimensional transport model for toroidal plasmas

    International Nuclear Information System (INIS)

    Copenhauer, C.

    1980-12-01

    A nonlinear MHD model, developed for three-dimensional toroidal geometries (asymmetric) and for high β (β approximately epsilon), is used as a basis for a three-dimensional transport model. Since inertia terms are needed in describing evolving magnetic islands, the model can calculate transport, both in the transient phase before nonlinear saturation of magnetic islands and afterwards on the resistive time scale. In the β approximately epsilon ordering, the plasma does not have sufficient energy to compress the parallel magnetic field, which allows the Alfven wave to be eliminated in the reduced nonlinear equations, and the model then follows the slower time scales. The resulting perpendicular and parallel plasma drift velocities can be identified with those of guiding center theory

  15. Investigations on the two-dimensional aperiodic plasma photonic crystals with fractal Fibonacci sequence

    Directory of Open Access Journals (Sweden)

    Hai-Feng Zhang

    2017-07-01

    Full Text Available In this paper, the properties of photonic band gaps (PBGs and defect modes of two-dimensional (2D fractal plasma photonic crystals (PPCs under a transverse-magnetic (TM wave are theoretically investigated by a modified plane wave expansion (PWE method. The configuration of 2D PPCs is the square lattices with the iteration rule of the Fibonacci sequence whose constituents are homogeneous and isotropic. The proposed 2D PPCs is filled with the dielectric cylinders in the plasma background. The accuracy and convergence of the present modified PWE method also are validated by a numerical example. The calculated results illustrate that the enough accuracy and good convergence can be achieved compared to the conventional PWE method, if the number of meshed grids is large enough. The dispersion curves of the proposed PPCs and 2D PPCs with a conventional square lattice are theoretically computed to study the properties of PBGs and defect modes. The simulated results demonstrate that the advantaged properties can be obtained in the proposed PPCs compared to the 2D conventional PPCs with similar lattices. If the Fibonacci sequence is introduced into the 2D PPCs, the larger PBGs and higher cutoff frequency can be achieved. The lower edges of PBGs are flat, which are originated from the Mie resonances. The defect modes can be considered as the quasi-localized states since the Fibonacci sequence has the self-similarity and non-periodicity at the same time. The effects of configurational parameters on the characters of the present PPCs are investigated. The results show that the PBGs and defect modes can be easily manipulated by tuning those parameters.

  16. Proteomic screen for multiprotein complexes in synaptic plasma membrane from rat hippocampus by blue native gel electrophoresis and tandem mass spectrometry.

    Science.gov (United States)

    Li, Xuanwen; Xie, Chunliang; Jin, Qihui; Liu, Mingjun; He, Quanyuan; Cao, Rui; Lin, Yong; Li, Jianglin; Li, Yan; Chen, Ping; Liang, Songping

    2009-07-01

    Neuronal synapses are specialized sites for information exchange between neurons. Many diseases, such as addiction and mood disorders, likely result from altered expression of synaptic proteins, or altered formation of synaptic complexes involved in neurotransmission or neuroplasticity. A detailed description of native multiprotein complexes in synaptic plasma membranes (PM) is therefore essential for understanding biological mechanisms and disease processes. For the first time in this study, two-dimensional Blue Native/SDS-PAGE electrophoresis, combined with tandem mass spectrometry, was used to screen multiprotein complexes in synaptic plasma membranes from rat hippocampus. As a result, 514 unique proteins were identified, of which 36% were integral membrane proteins. In addition, 19 potentially novel and known heterooligomeric multiprotein complexes were found, such as the SNARE and ATPase complexes. A potentially novel protein complex, involving syntaxin, synapsin I and Na+/K+ ATPase alpha-1, was further confirmed by co-immunoprecipitation and immunofluorescence staining. As demonstrated here, Blue Native-PAGE is a powerful tool for the separation of hydrophobic membrane proteins. The combination of Blue Native-PAGE and mass spectrometry could systematically identify multiprotein complexes.

  17. Two-dimensional errors

    International Nuclear Information System (INIS)

    Anon.

    1991-01-01

    This chapter addresses the extension of previous work in one-dimensional (linear) error theory to two-dimensional error analysis. The topics of the chapter include the definition of two-dimensional error, the probability ellipse, the probability circle, elliptical (circular) error evaluation, the application to position accuracy, and the use of control systems (points) in measurements

  18. Plasma kinetics of Ar/O{sub 2} magnetron discharge by two-dimensional multifluid modeling

    Energy Technology Data Exchange (ETDEWEB)

    Costin, C.; Minea, T. M.; Popa, G.; Gousset, G. [LPGP, UMR 8578, CNRS-Paris-Sud XI University, Bat. 210, Orsay Cedex 91405, France and Faculty of Physics, Al. I. Cuza University, 11 Carol I Blvd., Iasi 700506 (Romania); LPGP, UMR 8578, CNRS-Paris-Sud XI University, Bat. 210, Orsay Cedex 91405 (France); Faculty of Physics, Al. I. Cuza University, 11 Carol I Blvd., Iasi 700506 (Romania); LPGP, UMR 8578, CNRS-Paris-Sud XI University, Bat. 210, Orsay Cedex 91405 (France)

    2010-03-15

    Multifluid two-dimensional model was developed to describe the plasma kinetics of the direct current Ar/O{sub 2} magnetron, coupling two modules: charged particles and neutrals. The first module deals with three positive ions - Ar{sup +}, O{sub 2}{sup +}, and O{sup +} - and two negative species - e{sup -} and O{sup -} - treated by the moments of Boltzmann's equation. The second one follows seven neutral species (Ar, O{sub 2}, O, O{sub 3}, and related metastables) by the multicomponent diffusion technique. The two modules are self-consistently coupled by the mass conservation and kinetic coefficients taking into account more than 100 volume reactions. The steady state is obtained when the overall convergence is achieved. Calculations for 10%O{sub 2} in Ar/O{sub 2} mixture at 2.67 and 4 Pa show that the oxygen excited species are mainly created by electron collisions in the negative glow of the discharge. Decreasing the pressure down to 0.67 Pa, the model reveals the nonlocal behavior of the reactive species. The density gradient of O{sub 2} ground state is reversed with respect to all gradients of the other reactive species, since the latter ones originate from the molecular ground state of oxygen. It is also found that the wall reactions drastically modify the space gradient of neutral reactive species, at least as much as the pressure, even if the discharge operates in compound mode.

  19. A one-dimensional plasma and impurity transport model for reversed field pinches

    International Nuclear Information System (INIS)

    Veerasingam, R.

    1991-11-01

    In this thesis a one-dimensional (1-D) plasma and impurity transport model is developed to address issues related to impurity behavior in Reversed Field Pinch (RFP) fusion plasmas. A coronal non-equilibrium model is used for impurities. The impurity model is incorporated into an existing one dimensional plasma transport model creating a multi-species plasma transport model which treats the plasma and impurity evolution self-consistently. Neutral deuterium particles are treated using a one-dimensional (slab) model of neutral transport. The resulting mode, RFPBI, is then applied to existing RFP devices such as ZT-40M and MST, and also to examine steady state behavior of ZTH based on the design parameters. A parallel algorithm for the impurity transport equations is implemented and tested to determine speedup and efficiency

  20. Comprehensive lipidomic analysis of human plasma using multidimensional liquid- and gas-phase separations: Two-dimensional liquid chromatography-mass spectrometry vs. liquid chromatography-trapped-ion-mobility-mass spectrometry.

    Science.gov (United States)

    Baglai, Anna; Gargano, Andrea F G; Jordens, Jan; Mengerink, Ynze; Honing, Maarten; van der Wal, Sjoerd; Schoenmakers, Peter J

    2017-12-29

    Recent advancements in separation science have resulted in the commercialization of multidimensional separation systems that provide higher peak capacities and, hence, enable a more-detailed characterization of complex mixtures. In particular, two powerful analytical tools are increasingly used by analytical scientists, namely online comprehensive two-dimensional liquid chromatography (LC×LC, having a second-dimension separation in the liquid phase) and liquid chromatography-ion mobility-spectrometry (LC-IMS, second dimension separation in the gas phase). The goal of the current study was a general assessment of the liquid-chromatography-trapped-ion-mobility-mass spectrometry (LC-TIMS-MS) and comprehensive two-dimensional liquid chromatography-mass spectrometry (LC×LC-MS) platforms for untargeted lipid mapping in human plasma. For the first time trapped-ion-mobility spectrometry (TIMS) was employed for the separation of the major lipid classes and ion-mobility-derived collision-cross-section values were determined for a number of lipid standards. The general effects of a number of influencing parameters have been inspected and possible directions for improvements are discussed. We aimed to provide a general indication and practical guidelines for the analyst to choose an efficient multidimensional separation platform according to the particular requirements of the application. Analysis time, orthogonality, peak capacity, and an indicative measure for the resolving power are discussed as main characteristics for multidimensional separation systems. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Coherent vortical structures in two-dimensional plasma turbulence

    DEFF Research Database (Denmark)

    Pécseli, H.L.; Coutsias, E.A.; Huld, T.

    1992-01-01

    A laboratory experiment was carried out in order to study the nonlinear saturated stage of the cross-field electrostatic Kelvin-Helmholtz instability in a strongly magnetized plasma. The presence of large vortex-like structures in a background of wide-band turbulent fluctuations was demonstrated...... simulations. The importance of the large scale structures for the turbulent plasma transport across magnetic field lines was analyzed in detail....

  2. Two-dimensional simulations of magnetically-driven instabilities

    International Nuclear Information System (INIS)

    Peterson, D.; Bowers, R.; Greene, A.E.; Brownell, J.

    1986-01-01

    A two-dimensional Eulerian MHD code is used to study the evolution of magnetically-driven instabilities in cylindrical geometry. The code incorporates an equation of state, resistivity, and radiative cooling model appropriate for an aluminum plasma. The simulations explore the effects of initial perturbations, electrical resistivity, and radiative cooling on the growth and saturation of the instabilities. Comparisons are made between the 2-D simulations, previous 1-D simulations, and results from the Pioneer experiments of the Los Alamos foil implosion program

  3. 3-Dimensional Modeling of Capacitively and Inductively Coupled Plasma Etching Systems

    Science.gov (United States)

    Rauf, Shahid

    2008-10-01

    Low temperature plasmas are widely used for thin film etching during micro and nano-electronic device fabrication. Fluid and hybrid plasma models were developed 15-20 years ago to understand the fundamentals of these plasmas and plasma etching. These models have significantly evolved since then, and are now a major tool used for new plasma hardware design and problem resolution. Plasma etching is a complex physical phenomenon, where inter-coupled plasma, electromagnetic, fluid dynamics, and thermal effects all have a major influence. The next frontier in the evolution of fluid-based plasma models is where these models are able to self-consistently treat the inter-coupling of plasma physics with fluid dynamics, electromagnetics, heat transfer and magnetostatics. We describe one such model in this paper and illustrate its use in solving engineering problems of interest for next generation plasma etcher design. Our 3-dimensional plasma model includes the full set of Maxwell equations, transport equations for all charged and neutral species in the plasma, the Navier-Stokes equation for fluid flow, and Kirchhoff's equations for the lumped external circuit. This model also includes Monte Carlo based kinetic models for secondary electrons and stochastic heating, and can take account of plasma chemistry. This modeling formalism allows us to self-consistently treat the dynamics in commercial inductively and capacitively coupled plasma etching reactors with realistic plasma chemistries, magnetic fields, and reactor geometries. We are also able to investigate the influence of the distributed electromagnetic circuit at very high frequencies (VHF) on the plasma dynamics. The model is used to assess the impact of azimuthal asymmetries in plasma reactor design (e.g., off-center pump, 3D magnetic field, slit valve, flow restrictor) on plasma characteristics at frequencies from 2 -- 180 MHz. With Jason Kenney, Ankur Agarwal, Ajit Balakrishna, Kallol Bera, and Ken Collins.

  4. Complex plasmas scientific challenges and technological opportunities

    CERN Document Server

    Lopez, Jose; Becker, Kurt; Thomsen, Hauke

    2014-01-01

    This book provides the reader with an introduction to the physics of complex plasmas, a discussion of the specific scientific and technical challenges they present, and an overview of their potential technological applications. Complex plasmas differ from conventional high-temperature plasmas in several ways: they may contain additional species, including nanometer- to micrometer-sized particles, negative ions, molecules and radicals, and they may exhibit strong correlations or quantum effects. This book introduces the classical and quantum mechanical approaches used to describe and simulate complex plasmas. It also covers some key experimental techniques used in the analysis of these plasmas, including calorimetric probe methods, IR absorption techniques and X-ray absorption spectroscopy. The final part of the book reviews the emerging applications of microcavity and microchannel plasmas, the synthesis and assembly of nanomaterials through plasma electrochemistry, the large-scale generation of ozone using mi...

  5. Signatures of correlated excitonic dynamics in two-dimensional spectroscopy of the Fenna-Matthew-Olson photosynthetic complex

    International Nuclear Information System (INIS)

    Caram, Justin R.; Lewis, Nicholas H. C.; Fidler, Andrew F.; Engel, Gregory S.

    2012-01-01

    Long-lived excitonic coherence in photosynthetic proteins has become an exciting area of research because it may provide design principles for enhancing the efficiency of energy transfer in a broad range of materials. In this publication, we provide new evidence that long-lived excitonic coherence in the Fenna-Mathew-Olson pigment-protein (FMO) complex is consistent with the assumption of cross correlation in the site basis, indicating that each site shares bath fluctuations. We analyze the structure and character of the beating crosspeak between the two lowest energy excitons in two-dimensional (2D) electronic spectra of the FMO Complex. To isolate this dynamic signature, we use the two-dimensional linear prediction Z-transform as a platform for filtering coherent beating signatures within 2D spectra. By separating signals into components in frequency and decay rate representations, we are able to improve resolution and isolate specific coherences. This strategy permits analysis of the shape, position, character, and phase of these features. Simulations of the crosspeak between excitons 1 and 2 in FMO under different regimes of cross correlation verify that statistically independent site fluctuations do not account for the elongation and persistence of the dynamic crosspeak. To reproduce the experimental results, we invoke near complete correlation in the fluctuations experienced by the sites associated with excitons 1 and 2. This model contradicts ab initio quantum mechanic/molecular mechanics simulations that observe no correlation between the energies of individual sites. This contradiction suggests that a new physical model for long-lived coherence may be necessary. The data presented here details experimental results that must be reproduced for a physical model of quantum coherence in photosynthetic energy transfer.

  6. Three Dimensional Double Layers in Magnetized Plasmas

    DEFF Research Database (Denmark)

    Jovanovic, D.; Lynov, Jens-Peter; Michelsen, Poul

    1982-01-01

    Experimental results are presented which demonstrate the formation of fully three dimensional double layers in a magnetized plasma. The measurements are performed in a magnetized stationary plasma column with radius 1.5 cm. Double layers are produced by introducing an electron beam with radius 0.......4 cm along the magnetic field from one end of the column. The voltage drop across the double layer is found to be determined by the energy of the incoming electron beam. In general we find that the width of the double layer along the external magnetic field is determined by plasma density and beam...

  7. Single-shot ultrabroadband two-dimensional electronic spectroscopy of the light-harvesting complex LH2.

    Science.gov (United States)

    Harel, Elad; Long, Phillip D; Engel, Gregory S

    2011-05-01

    Here we present two-dimensional (2D) electronic spectra of the light-harvesting complex LH2 from purple bacteria using coherent pulses with bandwidth of over 100 nm FWHM. This broadband excitation and detection has allowed the simultaneous capture of both the B800 and B850 bands using a single light source. We demonstrate that one laser pulse is sufficient to capture the entire 2D electronic spectrum with a high signal-to-noise ratio. At a waiting time of 800 fs, we observe population transfer from the B800 to B850 band as manifested by a prominent cross peak. These results will enable observation of the dynamics of biological systems across both ultrafast (1 ms) timescales simultaneously.

  8. Grammatical complexity for two-dimensional maps

    International Nuclear Information System (INIS)

    Hagiwara, Ryouichi; Shudo, Akira

    2004-01-01

    We calculate the grammatical complexity of the symbol sequences generated from the Henon map and the Lozi map using the recently developed methods to construct the pruning front. When the map is hyperbolic, the language of symbol sequences is regular in the sense of the Chomsky hierarchy and the corresponding grammatical complexity takes finite values. It is found that the complexity exhibits a self-similar structure as a function of the system parameter, and the similarity of the pruning fronts is discussed as an origin of such self-similarity. For non-hyperbolic cases, it is observed that the complexity monotonically increases as we increase the resolution of the pruning front

  9. Grammatical complexity for two-dimensional maps

    Energy Technology Data Exchange (ETDEWEB)

    Hagiwara, Ryouichi; Shudo, Akira [Department of Physics, Tokyo Metropolitan University, Minami-Ohsawa, Hachioji, Tokyo 192-0397 (Japan)

    2004-11-05

    We calculate the grammatical complexity of the symbol sequences generated from the Henon map and the Lozi map using the recently developed methods to construct the pruning front. When the map is hyperbolic, the language of symbol sequences is regular in the sense of the Chomsky hierarchy and the corresponding grammatical complexity takes finite values. It is found that the complexity exhibits a self-similar structure as a function of the system parameter, and the similarity of the pruning fronts is discussed as an origin of such self-similarity. For non-hyperbolic cases, it is observed that the complexity monotonically increases as we increase the resolution of the pruning front.

  10. Grammatical complexity for two-dimensional maps

    Science.gov (United States)

    Hagiwara, Ryouichi; Shudo, Akira

    2004-11-01

    We calculate the grammatical complexity of the symbol sequences generated from the Hénon map and the Lozi map using the recently developed methods to construct the pruning front. When the map is hyperbolic, the language of symbol sequences is regular in the sense of the Chomsky hierarchy and the corresponding grammatical complexity takes finite values. It is found that the complexity exhibits a self-similar structure as a function of the system parameter, and the similarity of the pruning fronts is discussed as an origin of such self-similarity. For non-hyperbolic cases, it is observed that the complexity monotonically increases as we increase the resolution of the pruning front.

  11. Computer experiments on dynamical cloud and space time fluctuations in one-dimensional meta-equilibrium plasmas

    International Nuclear Information System (INIS)

    Rouet, J.L.; Feix, M.R.

    1996-01-01

    The test particle picture is a central theory of weakly correlated plasma. While experiments and computer experiments have confirmed the validity of this theory at thermal equilibrium, the extension to meta-equilibrium distributions presents interesting and intriguing points connected to the under or over-population of the tail of these distributions (high velocity) which have not yet been tested. Moreover, the general dynamical Debye cloud (which is a generalization of the static Debye cloud supposing a plasma at thermal equilibrium and a test particle of zero velocity) for any test particle velocity and three typical velocity distributions (equilibrium plus two meta-equilibriums) are presented. The simulations deal with a one-dimensional two-component plasma and, moreover, the relevance of the check for real three-dimensional plasma is outlined. Two kinds of results are presented: the dynamical cloud itself and the more usual density (or energy) fluctuation spectrums. Special attention is paid to the behavior of long wavelengths which needs long systems with very small graininess effects and, consequently, sizable computation efforts. Finally, the divergence or absence of energy in the small wave numbers connected to the excess or lack of fast particles of the two above mentioned meta-equilibrium is exhibited. copyright 1996 American Institute of Physics

  12. Dynamics of two-dimensional solitary vortices in a low-β plasma with convective motion

    International Nuclear Information System (INIS)

    Makino, Mitsuhiro; Kamimura, Tetsuo; Taniuti, Tosiya.

    1980-12-01

    Numerical studies of the Hasegawa-Mima equation, derived in the context of drift waves but equivalent to the quasigeostrophic vortex potential equation for Rossby waves, show the stable properties of solitary vortices which are two dimensional, localized, steady and translating solutions of this same equation. A solitary vortex can propagate only in the direction (x-direction) perpendicular to the density gradient. When this solitary vortex solution is inclined at some angle with respect to the x-axis, its propagation direction oscillates in the x and y plane. In two dimensional collisions, i.e. head-on collision and overtaking, solitary vortices interact two-dimensionally and recover their initial shapes at the end of both types of collisions. (author)

  13. One-dimensional plasma photonic crystals with sinusoidal densities

    International Nuclear Information System (INIS)

    Qi, L.; Shang, L.; Zhang, S.

    2014-01-01

    Properties of electromagnetic waves with normal and oblique incidence have been studied for one-dimensional plasma layers with sinusoidal densities. Wave transmittance as a function of wave frequency exhibits photonic band gaps characteristic of photonic crystals. For periodic structures, increasing collision frequency is demonstrated to lead to greater absorption, increasing the modulation factor enlarges the gap width, and increasing incidence angle can change the gap locations of the two polarizations. If a defect layer is introduced by inserting a new plasma layer in the center, a defect mode may appear within the gap. Periodic number, collision frequency, and modulation factor can affect magnitude of the defect mode. The incidence angle enables the frequency to be tuned. Defect layer thickness affects both frequency and number of defect modes. These results may provide theoretical guidance in designing tunable narrow-band filters

  14. Three-dimensional structure of the γ-secretase complex

    International Nuclear Information System (INIS)

    Ogura, Toshihiko; Mio, Kazuhiro; Hayashi, Ikuo; Miyashita, Hiroyuki; Fukuda, Rie; Kopan, Raphael; Kodama, Tatsuhiko; Hamakubo, Takao; Iwastubo, Takeshi; Tomita, Taisuke; Sato, Chikara

    2006-01-01

    γ-Secretase belongs to an atypical class of aspartic proteases that hydrolyzes peptide bonds within the transmembrane domain of substrates, including amyloid-β precursor protein and Notch. γ-Secretase is comprised of presenilin, nicastrin, APH-1, and PEN-2 which form a large multimeric membrane protein complex, the three-dimensional structure of which is unknown. To gain insight into the structure of this complex enzyme, we purified functional γ-secretase complex reconstituted in Sf9 cells and analyzed it using negative stain electron microscopy and 3D reconstruction techniques. Analysis of 2341 negatively stained particle images resulted in the three-dimensional representation of γ-secretase at a resolution of 48 A. The structure occupies a volume of 560 x 320 x 240 A and resembles a flat heart comprised of two oppositely faced, dimpled domains. A low density space containing multiple pores resides between the domains. Some of the dimples in the putative transmembrane region may house the catalytic site. The large dimensions are consistent with the observation that γ-secretase activity resides within a high molecular weight complex

  15. Plasma cloud expansion in the ionosphere: Three-dimensional simulation

    International Nuclear Information System (INIS)

    Ma, T.Z.; Schunk, R.W.

    1991-01-01

    A three-dimensional time-dependent model was developed to study the characteristics of a plasma cloud expansion in the ionosphere. The electrostatic potential is solved in three dimensions taking into account the large parallel-to-perpendicular conductivity ratio. Three sample simulations are presented: a plasma expansion of a nearly spherical 1 km Ba + cloud, both with and without a background neutral wind, and a long thin Ba + cloudlet. With or without the neutral wind the effective potential, which is different from the electrostatic potential if the electron temperature is included, is constant along the magnetic field for typical cloud sizes. The expanding plasma clouds become elongated in the magnetic field direction. The released Ba + ions push the background O + ions away along the magnetic field as they expand. Consequently, a hole develops in the background O + distribution at the cloud location and on the two sides of the cloud O + bumps form. The entire three-dimensional structure, composed of the plasma cloud and the background plasma embedded in the cloud, slowly rotates about the magnetic field, with the ions and electrons rotating in opposite directions. The cloud configuration takes the shape of a rotating ellipsoid with a major axis that expands with time. Perpendicular to the magnetic field, in the absence of the neutral wind the motion is insignificant compared to the parallel motion. With a neutral wind the motion along the magnetic field and the rotational motion are qualitatively unchanged, but the cloud and the perturbed background structure move in the direction of the wind, with a speed less than the wind speed. Perpendicular to the magnetic field the deformation of the cloud indiced by the wind is characterized by steepening of the backside

  16. ONE-DIMENSIONAL AND TWO-DIMENSIONAL LEADERSHIP STYLES

    Directory of Open Access Journals (Sweden)

    Nikola Stefanović

    2007-06-01

    Full Text Available In order to motivate their group members to perform certain tasks, leaders use different leadership styles. These styles are based on leaders' backgrounds, knowledge, values, experiences, and expectations. The one-dimensional styles, used by many world leaders, are autocratic and democratic styles. These styles lie on the two opposite sides of the leadership spectrum. In order to precisely define the leadership styles on the spectrum between the autocratic leadership style and the democratic leadership style, leadership theory researchers use two dimensional matrices. The two-dimensional matrices define leadership styles on the basis of different parameters. By using these parameters, one can identify two-dimensional styles.

  17. Dynamic complexity: plant receptor complexes at the plasma membrane.

    Science.gov (United States)

    Burkart, Rebecca C; Stahl, Yvonne

    2017-12-01

    Plant receptor complexes at the cell surface perceive many different external and internal signalling molecules and relay these signals into the cell to regulate development, growth and immunity. Recent progress in the analyses of receptor complexes using different live cell imaging approaches have shown that receptor complex formation and composition are dynamic and take place at specific microdomains at the plasma membrane. In this review we focus on three prominent examples of Arabidopsis thaliana receptor complexes and how their dynamic spatio-temporal distribution at the PM has been studied recently. We will elaborate on the newly emerging concept of plasma membrane microdomains as potential hubs for specific receptor complex assembly and signalling outputs. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Analysis of human plasma lipids by using comprehensive two-dimensional gas chromatography with dual detection and with the support of high-resolution time-of-flight mass spectrometry for structural elucidation.

    Science.gov (United States)

    Salivo, Simona; Beccaria, Marco; Sullini, Giuseppe; Tranchida, Peter Q; Dugo, Paola; Mondello, Luigi

    2015-01-01

    The main focus of the present research is the analysis of the unsaponifiable lipid fraction of human plasma by using data derived from comprehensive two-dimensional gas chromatography with dual quadrupole mass spectrometry and flame ionization detection. This approach enabled us to attain both mass spectral information and analyte percentage data. Furthermore, gas chromatography coupled with high-resolution time-of-flight mass spectrometry was used to increase the reliability of identification of several unsaponifiable lipid constituents. The synergism between both the high-resolution gas chromatography and mass spectrometry processes enabled us to attain a more in-depth knowledge of the unsaponifiable fraction of human plasma. Additionally, information was attained on the fatty acid and triacylglycerol composition of the plasma samples, subjected to investigation by using comprehensive two-dimensional gas chromatography with dual quadrupole mass spectrometry and flame ionization detection and high-performance liquid chromatography with atmospheric pressure chemical ionization quadrupole mass spectrometry, respectively. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. On the wake structure in streaming complex plasmas

    International Nuclear Information System (INIS)

    Ludwig, Patrick; Kählert, Hanno; Bonitz, Michael; Miloch, Wojciech J

    2012-01-01

    The theoretical description of complex (dusty) plasmas requires multiscale concepts that adequately incorporate the correlated interplay of streaming electrons and ions, neutrals and dust grains. Knowing the effective dust-dust interaction, the multiscale problem can be effectively reduced to a one-component plasma model of the dust subsystem. The goal of this paper is a systematic evaluation of the electrostatic potential distribution around a dust grain in the presence of a streaming plasma environment by means of two complementary approaches: (i) a high-precision computation of the dynamically screened Coulomb potential from the dynamic dielectric function and (ii) full 3D particle-in-cell simulations, which self-consistently include dynamical grain charging and nonlinear effects. The range of applicability of these two approaches is addressed. (paper)

  20. Acid-base properties of complexes with three-dimensional polyligands. Complexes with three-dimensional polyphosphoric acids

    International Nuclear Information System (INIS)

    Kopylova, V.D.; Bojko, Eh.T.; Saldadze, K.M.

    1985-01-01

    By the method of potentiometric titration acid-base properties of uranyl (2) complexes with three-dimensional polyphosphoric acids, KRF-8p, KF-1, KF-7 prepared by phosphorylation of copolymer of styrene and divinylbenzene or saponification of the copolymers of di-2,2'-chloroethyl ester of vinylphosphonic acid with divinyl benzene are studied. It is shown that in case of formation in the phase of three-dimensional polyphosphoric acids of UO 2 2+ complexes with the growth of bond covalence of metal ion-phosphonic group the acidjty of the second hydroxyl of the phosphonic group increases

  1. Are low-dimensional dynamics typical in magnetically confined plasmas?

    International Nuclear Information System (INIS)

    Ball, R.; Dewar, R.L.

    2000-01-01

    work we review the low-dimensional models of plasma behaviour that have been published to date, and re-examine them within the conceptual framework of singularity theory in order to derive a consensus model that is mathematically consistent and comparable to experimental observations. It is intuitively reasonable to expect that manifestly different models should be equivalent at some deeper level if they describe the same phenomena, and a recent work (Ball and Dewar, Phys. Rev. Lett. 84. 3077, 2000) has pointed the way towards unifying models that show profound qualitative differences. We use the generic consensus model as a prototype for a model of L-H transitions and oscillations in the H1 Heliac stellarator. Guided by the observation that arbitrarily close to a Hopf bifurcation the dynamics are approximately 2-dimensional we extract the two most important coupled state variables, that describe energy (or momentum) exchange between the turbulence and the sheared E x B flow. This fits in with the currently accepted paradigm whereby shear flow both causes and suppresses turbulence

  2. Numerical Computation of Wave-Plasma Interactions in Multi-Dimensional Systems

    International Nuclear Information System (INIS)

    D. A. D'Ippolito; J. R. Myra

    2005-01-01

    This project studied two kinds of nonlinear interactions between ion cyclotron range of frequency waves and fusion plasmas. A wavelet technique was also developed for analyzing the complex wave fields produced by wave propagation codes

  3. Bifurcations of solitary wave solutions for (two and three)-dimensional nonlinear partial differential equation in quantum and magnetized plasma by using two different methods

    Science.gov (United States)

    Khater, Mostafa M. A.; Seadawy, Aly R.; Lu, Dianchen

    2018-06-01

    In this research, we study new two techniques that called the extended simple equation method and the novel (G‧/G) -expansion method. The extended simple equation method depend on the auxiliary equation (dϕ/dξ = α + λϕ + μϕ2) which has three ways for solving depends on the specific condition on the parameters as follow: When (λ = 0) this auxiliary equation reduces to Riccati equation, when (α = 0) this auxiliary equation reduces to Bernoulli equation and when (α ≠ 0, λ ≠ 0, μ ≠ 0) we the general solutions of this auxiliary equation while the novel (G‧/G) -expansion method depends also on similar auxiliary equation (G‧/G)‧ = μ + λ(G‧/G) + (v - 1)(G‧/G) 2 which depend also on the value of (λ2 - 4 (v - 1) μ) and the specific condition on the parameters as follow: When (λ = 0) this auxiliary equation reduces to Riccati equation, when (μ = 0) this auxiliary equation reduces to Bernoulli equation and when (λ2 ≠ 4 (v - 1) μ) we the general solutions of this auxiliary equation. This show how both of these auxiliary equation are special cases of Riccati equation. We apply these methods on two dimensional nonlinear Kadomtsev-Petviashvili Burgers equation in quantum plasma and three-dimensional nonlinear modified Zakharov-Kuznetsov equation of ion-acoustic waves in a magnetized plasma. We obtain the exact traveling wave solutions of these important models and under special condition on the parameters, we get solitary traveling wave solutions. All calculations in this study have been established and verified back with the aid of the Maple package program. The executed method is powerful, effective and straightforward for solving nonlinear partial differential equations to obtain more and new solutions.

  4. Three-dimensional effects of curved plasma actuators in quiescent air

    International Nuclear Information System (INIS)

    Wang Chincheng; Durscher, Ryan; Roy, Subrata

    2011-01-01

    This paper presents results on a new class of curved plasma actuators for the inducement of three-dimensional vortical structures. The nature of the fluid flow inducement on a flat plate, in quiescent conditions, due to four different shapes of dielectric barrier discharge (DBD) plasma actuators is numerically investigated. The three-dimensional plasma kinetic equations are solved using our in-house, finite element based, multiscale ionized gas (MIG) flow code. Numerical results show electron temperature and three dimensional plasma force vectors for four shapes, which include linear, triangular, serpentine, and square actuators. Three-dimensional effects such as pinching and spreading the neighboring fluid are observed for serpentine and square actuators. The mechanisms of vorticity generation for DBD actuators are discussed. Also the influence of geometric wavelength (λ) and amplitude (Λ) of the serpentine and square actuators on vectored thrust inducement is predicted. This results in these actuators producing significantly better flow mixing downstream as compared to the standard linear actuator. Increasing the wavelengths of serpentine and square actuators in the spanwise direction is shown to enhance the pinching effect giving a much higher vertical velocity. On the contrary, changing the amplitude of the curved actuator varies the streamwise velocity significantly influencing the near wall jet. Experimental data for a serpentine actuator are also reported for validation purpose.

  5. Heteromeric Complexes of Native Collectin Kidney 1 and Collectin Liver 1 Are Found in the Circulation with MASPs and Activate the Complement System

    DEFF Research Database (Denmark)

    Henriksen, Maiken L; Brandt, Jette; Andrieu, Jean-Piere

    2013-01-01

    of carbohydrates or acetylated molecules. During purification and characterization of native CL-K1 from plasma, we observed that collectin liver 1 (CL-L1) was copurified. Based on deglycosylation and nonreduced/reduced two-dimensional SDS-PAGE, we detected CL-K1 and CL-L1 in disulfide bridge-stabilized complexes....... Heteromeric complex formation in plasma was further shown by ELISA and transient coexpression. Judging from the migration pattern on two-dimensional SDS-PAGE, the majority of plasma CL-K1 was found in complex with CL-L1. The ratio of this complex was in favor of CL-K1, suggesting that a heteromeric subunit...

  6. Two-dimensional NMR spectrometry

    International Nuclear Information System (INIS)

    Farrar, T.C.

    1987-01-01

    This article is the second in a two-part series. In part one (ANALYTICAL CHEMISTRY, May 15) the authors discussed one-dimensional nuclear magnetic resonance (NMR) spectra and some relatively advanced nuclear spin gymnastics experiments that provide a capability for selective sensitivity enhancements. In this article and overview and some applications of two-dimensional NMR experiments are presented. These powerful experiments are important complements to the one-dimensional experiments. As in the more sophisticated one-dimensional experiments, the two-dimensional experiments involve three distinct time periods: a preparation period, t 0 ; an evolution period, t 1 ; and a detection period, t 2

  7. Two- and three-dimensional evaluation of the acetabulum in the pediatric patient

    International Nuclear Information System (INIS)

    Magid, D.; Fishman, E.K.; Sponseller, P.D.

    1987-01-01

    Complex anatomic structures such as the hip and acetabulum are best evaluated with the use of two- and three-dimensional reconstruction techniques and standard transaxial CT data. CT scans of children with various hip pathologies, including congenital hip dislocation, slipped capital femoral epiphyses, hip dysplasias, dwarfism, and acetabular fractures, were reviewed to determine the value of two- and three-dimensional imaging. The advantages of two-dimensional imaging techniques (sequential coronal/sagittal reconstruction) and three-dimensional valumetric imaging techniques (using real-time video display) are illustrated with specific examples

  8. Normal Modes of Magnetized Finite Two-Dimensional Yukawa Crystals

    Science.gov (United States)

    Marleau, Gabriel-Dominique; Kaehlert, Hanno; Bonitz, Michael

    2009-11-01

    The normal modes of a finite two-dimensional dusty plasma in an isotropic parabolic confinement, including the simultaneous effects of friction and an external magnetic field, are studied. The ground states are found from molecular dynamics simulations with simulated annealing, and the influence of screening, friction, and magnetic field on the mode frequencies is investigated in detail. The two-particle problem is solved analytically and the limiting cases of weak and strong magnetic fields are discussed.[4pt] [1] C. Henning, H. K"ahlert, P. Ludwig, A. Melzer, and M.Bonitz. J. Phys. A 42, 214023 (2009)[2] B. Farokhi, M. Shahmansouri, and P. K. Shukla. Phys.Plasmas 16, 063703 (2009)[3] L. Cândido, J.-P. Rino, N. Studart, and F. M. Peeters. J. Phys.: Condens. Matter 10, 11627--11644 (1998)

  9. Dynamical properties of magnetized two-dimensional one-component plasma

    Science.gov (United States)

    Dubey, Girija S.; Gumbs, Godfrey; Fessatidis, Vassilios

    2018-05-01

    Molecular dynamics simulation are used to examine the effect of a uniform perpendicular magnetic field on a two-dimensional interacting electron system. In this simulation we include the effect of the magnetic field classically through the Lorentz force. Both the Coulomb and the magnetic forces are included directly in the electron dynamics to study their combined effect on the dynamical properties of the 2D system. Results are presented for the velocity autocorrelation function and the diffusion constants in the presence and absence of an external magnetic field. Our simulation results clearly show that the external magnetic field has an effect on the dynamical properties of the system.

  10. Code improvements and applications of a two-dimensional edge plasma model for toroidal devices

    International Nuclear Information System (INIS)

    Baelmans, M.

    1994-03-01

    This thesis focuses mainly on plasma behaviour in boundary layers of magnetically confined plasmas. Increasing emphasis has been put on edge studies during the last decade, as it became evident that some aspects of Tokamak operations are largely controlled, or even dominated, by edge processes. Therefore, the motivation for this research is to improve understanding of plasma behaviour in general, and edge plasma behaviour in particular, firstly in present experiments, and also to predict edge plasma conditions in future nuclear fusion devices. In a first section some fundamental concepts and principles of controlled fusion are described. Two different types of plasma confinement concepts which have promising features with regard to the above mentioned goal are outlined in a next section, 1.2. In section 1.3 an introduction to plasma edge phenomena is given. In a last section, 1.4, the outline of the thesis is described. (orig.)

  11. Study of Complex Plasmas with Magnetic Dipoles

    Science.gov (United States)

    2017-10-10

    Electro-Energetic Physics Annual Program Review , Basic Research Innovation and Collaboration Center, Arlington VA USA, November 29-30, 2016 (6) The...and O. Ishihara, Electromagnetic band structure due to surface plasmon resonances in a complex plasma, Physical Review E, 94, 013202- 1~8 (2016). 7...Novel Features in Complex Plasmas, 2016 Plasma & Electro-Energetic Physics Annual Program Review , Basic Research Innovation and Collaboration Center

  12. Simulation of two-dimensional interior ballistics model of solid propellant electrothermal-chemical launch with discharge rod plasma generator

    Directory of Open Access Journals (Sweden)

    Yan-jie Ni

    2017-08-01

    Full Text Available Instead of the capillary plasma generator (CPG, a discharge rod plasma generator (DRPG is used in the 30 mm electrothermal-chemical (ETC gun to improve the ignition uniformity of the solid propellant. An axisymmetric two-dimensional interior ballistics model of the solid propellant ETC gun (2D-IB-SPETCG is presented to describe the process of the ETC launch. Both calculated pressure and projectile muzzle velocity accord well with the experimental results. The feasibility of the 2D-IB-SPETCG model is proved. Depending on the experimental data and initial parameters, detailed distribution of the ballistics parameters can be simulated. With the distribution of pressure and temperature of the gas phase and the propellant, the influence of plasma during the ignition process can be analyzed. Because of the radial flowing plasma, the propellant in the area of the DRPG is ignited within 0.01 ms, while all propellant in the chamber is ignited within 0.09 ms. The radial ignition delay time is much less than the axial delay time. During the ignition process, the radial pressure difference is less than 5  MPa at the place 0.025 m away from the breech. The radial ignition uniformity is proved. The temperature of the gas increases from several thousand K (conventional ignition to several ten thousand K (plasma ignition. Compare the distribution of the density and temperature of the gas, we know that low density and high temperature gas appears near the exits of the DRPG, while high density and low temperature gas appears at the wall near the breech. The simulation of the 2D-IB-SPETCG model is an effective way to investigate the interior ballistics process of the ETC launch. The 2D-IB-SPETC model can be used for prediction and improvement of experiments.

  13. Two-dimensional magnetic field evolution measurements and plasma flow speed estimates from the coaxial thruster experiment

    International Nuclear Information System (INIS)

    Black, D.C.; Mayo, R.M.; Gerwin, R.A.; Schoenberg, K.F.; Scheuer, J.T.; Hoyt, R.P.; Henins, I.

    1994-01-01

    Local, time-dependent magnetic field measurements have been made in the Los Alamos coaxial thruster experiment (CTX) [C. W. Barnes et al., Phys. Fluids B 2, 1871 (1990); J. C. Fernandez et al., Nucl. Fusion 28, 1555 (1988)] using a 24 coil magnetic probe array (eight spatial positions, three axis probes). The CTX is a magnetized, coaxial plasma gun presently being used to investigate the viability of high pulsed power plasma thrusters for advanced electric propulsion. Previous efforts on this device have indicated that high pulsed power plasma guns are attractive candidates for advanced propulsion that employ ideal magnetohydrodynamic (MHD) plasma stream flow through self-formed magnetic nozzles. Indirect evidence of magnetic nozzle formation was obtained from plasma gun performance and measurements of directed axial velocities up to v z ∼10 7 cm/s. The purpose of this work is to make direct measurement of the time evolving magnetic field topology. The intent is to both identify that applied magnetic field distortion by the highly conductive plasma is occurring, and to provide insight into the details of discharge evolution. Data from a magnetic fluctuation probe array have been used to investigate the details of applied magnetic field deformation through the reconstruction of time-dependent flux profiles. Experimentally observed magnetic field line distortion has been compared to that predicted by a simple one-dimensional (1-D) model of the discharge channel. Such a comparison is utilized to estimate the axial plasma velocity in the thruster. Velocities determined in this manner are in approximate agreement with the predicted self-field magnetosonic speed and those measured by a time-of-flight spectrometer

  14. Two dimensional infinite conformal symmetry

    International Nuclear Information System (INIS)

    Mohanta, N.N.; Tripathy, K.C.

    1993-01-01

    The invariant discontinuous (discrete) conformal transformation groups, namely the Kleinian and Fuchsian groups Gamma (with an arbitrary signature) of H (the Poincare upper half-plane l) and the unit disc Delta are explicitly constructed from the fundamental domain D. The Riemann surface with signatures of Gamma and conformally invariant automorphic forms (functions) with Peterson scalar product are discussed. The functor, where the category of complex Hilbert spaces spanned by the space of cusp forms constitutes the two dimensional conformal field theory. (Author) 7 refs

  15. Binding Direction-Based Two-Dimensional Flattened Contact Area Computing Algorithm for Protein-Protein Interactions.

    Science.gov (United States)

    Kang, Beom Sik; Pugalendhi, GaneshKumar; Kim, Ku-Jin

    2017-10-13

    Interactions between protein molecules are essential for the assembly, function, and regulation of proteins. The contact region between two protein molecules in a protein complex is usually complementary in shape for both molecules and the area of the contact region can be used to estimate the binding strength between two molecules. Although the area is a value calculated from the three-dimensional surface, it cannot represent the three-dimensional shape of the surface. Therefore, we propose an original concept of two-dimensional contact area which provides further information such as the ruggedness of the contact region. We present a novel algorithm for calculating the binding direction between two molecules in a protein complex, and then suggest a method to compute the two-dimensional flattened area of the contact region between two molecules based on the binding direction.

  16. Binding Direction-Based Two-Dimensional Flattened Contact Area Computing Algorithm for Protein–Protein Interactions

    Directory of Open Access Journals (Sweden)

    Beom Sik Kang

    2017-10-01

    Full Text Available Interactions between protein molecules are essential for the assembly, function, and regulation of proteins. The contact region between two protein molecules in a protein complex is usually complementary in shape for both molecules and the area of the contact region can be used to estimate the binding strength between two molecules. Although the area is a value calculated from the three-dimensional surface, it cannot represent the three-dimensional shape of the surface. Therefore, we propose an original concept of two-dimensional contact area which provides further information such as the ruggedness of the contact region. We present a novel algorithm for calculating the binding direction between two molecules in a protein complex, and then suggest a method to compute the two-dimensional flattened area of the contact region between two molecules based on the binding direction.

  17. Partition function zeros for the one-dimensional ordered plasma in Dirichlet boundary conditions

    International Nuclear Information System (INIS)

    Roumeliotis, J.; Smith, E.R.

    1992-01-01

    The authors consider the grand canonical partition function for the ordered one-dimensional, two-component plasma at fugacity ζ in an applied electric field E with Dirichlet boundary conditions. The system has a phase transition from a low-coupling phase with equally spaced particles to a high-coupling phase with particles clustered into dipolar pairs. An exact expression for the partition function is developed. In zero applied field the zeros in the ζ plane occupy the imaginary axis from -i∞ to -iζ c and iζ c to i∞ for some ζ c . They also occupy the diamond shape of four straight lines from ±iζ c to ζ c and from ±iζ c to -ζ c . The fugacity ζ acts like a temperature or coupling variable. The symmetry-breaking field is the applied electric field E. A finite-size scaling representation for the partition in scaled coupling and scaled electric field is developed. It has standard mean field form. When the scaled coupling is real, the zeros in the scaled field lie on the imaginary axis and pinch the real scaled field axis as the scaled coupling increases. The scaled partition function considered as a function of two complex variables, scaled coupling and scaled field, has zeros on a two-dimensional surface in a domain of four real variables. A numerical discussion of some of the properties of this surface is presented

  18. Two- and three-dimensional CT evaluation of sacral and pelvic anomalies

    International Nuclear Information System (INIS)

    Kuhlman, J.E.; Fishman, E.K.; Magid, D.

    1988-01-01

    Pelvic anomalies are difficult to evaluate with standard techniques. Detailed knowledge of the existing pelvic structures and musculature is essential for successful repair. The authors evaluated 12 patients with complex malformations of the pelvis using two- and three-dimensional imaging. The anomalies included bladder exstrophy (n = 4), cloacal exstrophy (n = 1), duplicated and absent sacrum (n = 3), myelomeningoceles (n = 2), and diastrophic dwarfism (n = 2). The two-dimensional images consisted of sequential coronal and sagittal reconstructions that could be reviewed dynamically on screen. Three-dimensional images were generated on the Pixar imaging computer with use of volumetric rendering. Two- and three-dimensional CT proved complementary in the evaluation of pelvic anomalies, providing optimal information from transaxial CT data

  19. One-dimensional nonlinear self-organized structures in dusty plasmas

    International Nuclear Information System (INIS)

    Tsytovich, V.N.

    2000-01-01

    Dusty plasmas, which are open systems, can form stable one-dimensional self-organized structures. Absorption of plasma by dust particles results in the plasma flux from the plasma regions where the dust is absent. It is found that, in a one-dimensional dust layer, this flux is completely determined by the number of dust particles per unit area of the layer surface. This number determines all of the other parameters of the steady-state dust structure; in particular, it determines the spatial distributions of the dust density, dust charge, electron and ion densities, and ion drift velocity. In these structures, a force and electrostatic balance is established that ensures the necessary conditions for confining the dust and plasma particles in the structure. The equilibrium structures exist only for subthermal ion flow velocities. This criterion determines the maximum possible number of dust particles per unit area in the steady-state structure. The structures have a universal thickness, and the dust density changes sharply at the edge of the structure. The structures with a size either less than or larger than the ion mean free path with respect to ion-neutral collisions, quasi-neutral and charged structures, and soliton- and anti-soliton-like structures are investigated. Laboratory experiments and observations in extraterrestrial plasma formation are discussed in relation to dust structures

  20. Tracking shocked dust: State estimation for a complex plasma during a shock wave

    International Nuclear Information System (INIS)

    Oxtoby, Neil P.; Ralph, Jason F.; Durniak, Celine; Samsonov, Dmitry

    2012-01-01

    We consider a two-dimensional complex (dusty) plasma crystal excited by an electrostatically-induced shock wave. Dust particle kinematics in such a system are usually determined using particle tracking velocimetry. In this work we present a particle tracking algorithm which determines the dust particle kinematics with significantly higher accuracy than particle tracking velocimetry. The algorithm uses multiple extended Kalman filters to estimate the particle states and an interacting multiple model to assign probabilities to the different filters. This enables the determination of relevant physical properties of the dust, such as kinetic energy and kinetic temperature, with high precision. We use a Hugoniot shock-jump relation to calculate a pressure-volume diagram from the shocked dust kinematics. Calculation of the full pressure-volume diagram was possible with our tracking algorithm, but not with particle tracking velocimetry.

  1. Exact complex integrals in two dimensions for shifted harmonic ...

    Indian Academy of Sciences (India)

    We use rationalization method to study two-dimensional complex dynamical systems (shifted harmonic oscillator in complex plane) on the extended comples phase space (ECPS). The role and scope of the derived invatiants in the context of various physical problems are high-lighted.

  2. Analysis of photonic band gap in dispersive properties of tunable three-dimensional photonic crystals doped by magnetized plasma

    International Nuclear Information System (INIS)

    Zhang HaiFeng; Liu Shaobin; Yang Huan; Kong Xiangkun

    2013-01-01

    In this paper, the magnetooptical effects in dispersive properties for two types of three-dimensional magnetized plasma photonic crystals (MPPCs) containing homogeneous dielectric and magnetized plasma with diamond lattices are theoretically investigated for electromagnetic (EM) wave based on plane wave expansion (PWE) method, as incidence EM wave vector is parallel to the external magnetic field. The equations for two types of MPPCs with diamond lattices (dielectric spheres immersed in magnetized plasma background or vice versa) are theoretically deduced. The influences of dielectric constant, plasma collision frequency, filling factor, the external magnetic field, and plasma frequency on the dispersive properties for both types of structures are studied in detail, respectively, and some corresponding physical explanations are also given. From the numerical results, it has been shown that the photonic band gaps (PBGs) for both types of MPPCs can be manipulated by plasma frequency, filling factor, the external magnetic field, and the relative dielectric constant of dielectric, respectively. Especially, the external magnetic field can enlarge the PBG for type-2 structure (plasma spheres immersed in dielectric background). However, the plasma collision frequency has no effect on the dispersive properties of two types of three-dimensional MPPCs. The locations of flatbands regions for both types of structures cannot be tuned by any parameters except for plasma frequency and the external magnetic field. The analytical results may be informative and of technical use to design the MPPCs devices.

  3. Two-dimensional fingerprinting approach for comparison of complex substances analysed by HPLC-UV and fluorescence detection.

    Science.gov (United States)

    Ni, Yongnian; Liu, Ying; Kokot, Serge

    2011-02-07

    This work is concerned with the research and development of methodology for analysis of complex mixtures such as pharmaceutical or food samples, which contain many analytes. Variously treated samples (swill washed, fried and scorched) of the Rhizoma atractylodis macrocephalae (RAM) traditional Chinese medicine (TCM) as well as the common substitute, Rhizoma atractylodis (RA) TCM were chosen as examples for analysis. A combined data matrix of chromatographic 2-D HPLC-DAD-FLD (two-dimensional high performance liquid chromatography with diode array and fluorescence detectors) fingerprint profiles was constructed with the use of the HPLC-DAD and HPLC-FLD individual data matrices; the purpose was to collect maximum information and to interpret this complex data with the use of various chemometrics methods e.g. the rank-ordering multi-criteria decision making (MCDM) PROMETHEE and GAIA, K-nearest neighbours (KNN), partial least squares (PLS), back propagation-artificial neural networks (BP-ANN) methods. The chemometrics analysis demonstrated that the combined 2-D HPLC-DAD-FLD data matrix does indeed provide more information and facilitates better performing classification/prediction models for the analysis of such complex samples as the RAM and RA ones noted above. It is suggested that this fingerprint approach is suitable for analysis of other complex, multi-analyte substances.

  4. Dark and bright solitons for the two-dimensional complex modified Korteweg-de Vries and Maxwell-Bloch system with time-dependent coefficient

    Science.gov (United States)

    Shaikhova, G.; Ozat, N.; Yesmakhanova, K.; Bekova, G.

    2018-02-01

    In this work, we present Lax pair for two-dimensional complex modified Korteweg-de Vries and Maxwell-Bloch (cmKdV-MB) system with the time-dependent coefficient. Dark and bright soliton solutions for the cmKdV-MB system with variable coefficient are received by Darboux transformation. Moreover, the determinant representation of the one-fold and two-fold Darboux transformation for the cmKdV-MB system with time-dependent coefficient is presented.

  5. Two-dimensional Schrödinger symmetry and three-dimensional breathers and Kelvin-ripple complexes as quasi-massive-Nambu-Goldstone modes

    Science.gov (United States)

    Takahashi, Daisuke A.; Ohashi, Keisuke; Fujimori, Toshiaki; Nitta, Muneto

    2017-08-01

    Bose-Einstein condensates (BECs) confined in a two-dimensional (2D) harmonic trap are known to possess a hidden 2D Schrödinger symmetry, that is, the Schrödinger symmetry modified by a trapping potential. Spontaneous breaking of this symmetry gives rise to a breathing motion of the BEC, whose oscillation frequency is robustly determined by the strength of the harmonic trap. In this paper, we demonstrate that the concept of the 2D Schrödinger symmetry can be applied to predict the nature of three-dimensional (3D) collective modes propagating along a condensate confined in an elongated trap. We find three kinds of collective modes whose existence is robustly ensured by the Schrödinger symmetry, which are physically interpreted as one breather mode and two Kelvin-ripple complex modes, i.e., composite modes in which the vortex core and the condensate surface oscillate interactively. We provide analytical expressions for the dispersion relations (energy-momentum relation) of these modes using the Bogoliubov theory [D. A. Takahashi and M. Nitta, Ann. Phys. 354, 101 (2015), 10.1016/j.aop.2014.12.009]. Furthermore, we point out that these modes can be interpreted as "quasi-massive-Nambu-Goldstone (NG) modes", that is, they have the properties of both quasi-NG and massive NG modes: quasi-NG modes appear when a symmetry of a part of a Lagrangian, which is not a symmetry of a full Lagrangian, is spontaneously broken, while massive NG modes appear when a modified symmetry is spontaneously broken.

  6. Pressure of two-dimensional Yukawa liquids

    International Nuclear Information System (INIS)

    Feng, Yan; Wang, Lei; Tian, Wen-de; Goree, J; Liu, Bin

    2016-01-01

    A simple analytic expression for the pressure of a two-dimensional Yukawa liquid is found by fitting results from a molecular dynamics simulation. The results verify that the pressure can be written as the sum of a potential term which is a simple multiple of the Coulomb potential energy at a distance of the Wigner–Seitz radius, and a kinetic term which is a multiple of the one for an ideal gas. Dimensionless coefficients for each of these terms are found empirically, by fitting. The resulting analytic expression, with its empirically determined coefficients, is plotted as isochores, or curves of constant area. These results should be applicable to monolayer dusty plasmas. (paper)

  7. Particle tracking from image sequences of complex plasma crystals

    International Nuclear Information System (INIS)

    Hadziavdic, Vedad; Melandsoe, Frank; Hanssen, Alfred

    2006-01-01

    In order to gather information about the physics of the complex plasma crystals from the experimental data, particles have to be tracked through a sequence of images. An application of the Kalman filter for that purpose is presented, using a one-dimensional approximation of the particle dynamics as a model for the filter. It is shown that Kalman filter is capable of tracking dust particles even with high levels of measurement noise. An inherent part of the Kalman filter, the innovation process, can be used to estimate values of the physical system parameters from the experimental data. The method is shown to be able to estimate the characteristic oscillation frequency from noisy data

  8. One-dimensional crystal with a complex periodic potential

    International Nuclear Information System (INIS)

    Boyd, John K.

    2001-01-01

    A one-dimensional crystal model is constructed with a complex periodic potential. A wave function solution for the crystal model is derived without relying on Bloch functions. The new wave function solution of this model is shown to correspond to the solution for the probability amplitude of a two-level system. The energy discriminant is evaluated using an analytic formula derived from the probability amplitude solution, and based on an expansion parameter related to the energy and potential amplitude. From the wave function energy discriminant the crystal band structure is derived and related to standard energy bands and gaps. It is also shown that several of the properties of the two-level system apply to the one-dimensional crystal model. The two-level system solution which evolves in time is shown to manifest as a spatial configuration of the one-dimensional crystal model. The sensitivity of the wave function probability density is interpreted in the context of the new solution. The spatial configuration of the wave function, and the appearance of a long wavelength in the wave function probability density is explained in terms of the properties of Bessel functions

  9. Study of two-dimensional interchange turbulence

    International Nuclear Information System (INIS)

    Sugama, Hideo; Wakatani, Masahiro.

    1990-04-01

    An eddy viscosity model describing enstrophy transfer in two-dimensional turbulence is presented. This model is similar to that of Canuto et al. and provides an equation for the energy spectral function F(k) as a function of the energy input rate to the system per unit wavenumber, γ s (k). In the enstrophy-transfer inertial range, F(k)∝ k -3 is predicted by the model. The eddy viscosity model is applied to the interchange turbulence of a plasma in shearless magnetic field. Numerical simulation of the two-dimensional interchange turbulence demonstrates that the energy spectrum in the high wavenumber region is well described by this model. The turbulent transport driven by the interchange turbulence is expressed in terms of the Nusselt number Nu, the Rayleigh number Ra and Prantl number Pr in the same manner as that of thermal convection problem. When we use the linear growth rate for γ s (k), our theoretical model predicts that Nu ∝ (Ra·Pr) 1/2 for a constant background pressure gradient and Nu ∝ (Ra·Pr) 1/3 for a self-consistent background pressure profile with the stress-free slip boundary conditions. The latter agrees with our numerical result showing Nu ∝ Ra 1/3 . (author)

  10. Three-dimensional two-fluid Braginskii simulations of the large plasma device

    Energy Technology Data Exchange (ETDEWEB)

    Fisher, Dustin M., E-mail: dustin.m.fisher.gr@dartmouth.edu; Rogers, Barrett N., E-mail: barrett.rogers@dartmouth.edu [Department of Physics and Astronomy, Dartmouth College, Hanover, New Hampshire 03755 (United States); Rossi, Giovanni D.; Guice, Daniel S.; Carter, Troy A. [Department of Physics and Astronomy, University of California, Los Angeles, California 90095-1547 (United States)

    2015-09-15

    The Large Plasma Device (LAPD) is modeled using the 3D Global Braginskii Solver code. Comparisons to experimental measurements are made in the low-bias regime in which there is an intrinsic E × B rotation of the plasma. In the simulations, this rotation is caused primarily by sheath effects and may be a likely mechanism for the intrinsic rotation seen in LAPD. Simulations show strong qualitative agreement with the data, particularly the radial dependence of the density fluctuations, cross-correlation lengths, radial flux dependence outside of the cathode edge, and camera imagery. Kelvin Helmholtz (KH) turbulence at relatively large scales is the dominant driver of cross-field transport in these simulations with smaller-scale drift waves and sheath modes playing a secondary role. Plasma holes and blobs arising from KH vortices in the simulations are consistent with the scale sizes and overall appearance of those in LAPD camera images. The addition of ion-neutral collisions in the simulations at previously theorized values reduces the radial particle flux by about a factor of two, from values that are somewhat larger than the experimentally measured flux to values that are somewhat lower than the measurements. This reduction is due to a modest stabilizing contribution of the collisions on the KH-modes driving the turbulent transport.

  11. The applications of Complexity Theory and Tsallis Non-extensive Statistics at Solar Plasma Dynamics

    Science.gov (United States)

    Pavlos, George

    2015-04-01

    theories, based on the classical central limit theorem (CLT), to explain the complexity of the solar wind dynamics, since these theories include smooth and differentiable spatial-temporal functions (MHD theory) or Gaussian statistics (Boltzmann-Maxwell statistical mechanics). On the contrary, the results of this study indicate the presence of non-Gaussian non-extensive statistics with heavy tails probability distribution functions, which are related to the q-extension of CLT. Finally, the results of this study can be understood in the framework of modern theoretical concepts such as non-extensive statistical mechanics (Tsallis, 2009), fractal topology (Zelenyi and Milovanov, 2004), turbulence theory (Frisch, 1996), strange dynamics (Zaslavsky, 2002), percolation theory (Milovanov, 1997), anomalous diffusion theory and anomalous transport theory (Milovanov, 2001), fractional dynamics (Tarasov, 2013) and non-equilibrium phase transition theory (Chang, 1992). References 1. T. Arimitsu, N. Arimitsu, Tsallis statistics and fully developed turbulence, J. Phys. A: Math. Gen. 33 (2000) L235. 2. T. Arimitsu, N. Arimitsu, Analysis of turbulence by statistics based on generalized entropies, Physica A 295 (2001) 177-194. 3. T. Chang, Low-dimensional behavior and symmetry braking of stochastic systems near criticality can these effects be observed in space and in the laboratory, IEEE 20 (6) (1992) 691-694. 4. U. Frisch, Turbulence, Cambridge University Press, Cambridge, UK, 1996, p. 310. 5. L.P. Karakatsanis, G.P. Pavlos, M.N. Xenakis, Tsallis non-extensive statistics, intermittent turbulence, SOC and chaos in the solar plasma. Part two: Solar flares dynamics, Physica A 392 (2013) 3920-3944. 6. A.V. Milovanov, Topological proof for the Alexander-Orbach conjecture, Phys. Rev. E 56 (3) (1997) 2437-2446. 7. A.V. Milovanov, L.M. Zelenyi, Fracton excitations as a driving mechanism for the self-organized dynamical structuring in the solar wind, Astrophys. Space Sci. 264 (1-4) (1999) 317

  12. Solute-solvent complex switching dynamics of chloroform between acetone and dimethylsulfoxide-two-dimensional IR chemical exchange spectroscopy.

    Science.gov (United States)

    Kwak, Kyungwon; Rosenfeld, Daniel E; Chung, Jean K; Fayer, Michael D

    2008-11-06

    Hydrogen bonds formed between C-H and various hydrogen bond acceptors play important roles in the structure of proteins and organic crystals, and the mechanisms of C-H bond cleavage reactions. Chloroform, a C-H hydrogen bond donor, can form weak hydrogen-bonded complexes with acetone and with dimethylsulfoxide (DMSO). When chloroform is dissolved in a mixed solvent consisting of acetone and DMSO, both types of hydrogen-bonded complexes exist. The two complexes, chloroform-acetone and chloroform-DMSO, are in equilibrium, and they rapidly interconvert by chloroform exchanging hydrogen bond acceptors. This fast hydrogen bond acceptor substitution reaction is probed using ultrafast two-dimensional infrared (2D-IR) vibrational echo chemical exchange spectroscopy. Deuterated chloroform is used in the experiments, and the 2D-IR spectrum of the C-D stretching mode is measured. The chemical exchange of the chloroform hydrogen bonding partners is tracked by observing the time-dependent growth of off-diagonal peaks in the 2D-IR spectra. The measured substitution rate is 1/30 ps for an acetone molecule to replace a DMSO molecule in a chloroform-DMSO complex and 1/45 ps for a DMSO molecule to replace an acetone molecule in a chloroform-acetone complex. Free chloroform exists in the mixed solvent, and it acts as a reactive intermediate in the substitution reaction, analogous to a SN1 type reaction. From the measured rates and the equilibrium concentrations of acetone and DMSO, the dissociation rates for the chloroform-DMSO and chloroform-acetone complexes are found to be 1/24 ps and 1/5.5 ps, respectively. The difference between the measured rate for the complete substitution reaction and the rate for complex dissociation corresponds to the diffusion limited rate. The estimated diffusion limited rate agrees well with the result from a Smoluchowski treatment of diffusive reactions.

  13. Three species one-dimensional kinetic model for weakly ionized plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, J., E-mail: jorge.gonzalez@upm.es; Donoso, J. M.; Tierno, S. P. [Department of Applied Physics, Escuela Técnica Superior de Ingeniería Aeronáutica y del Espacio, Universidad Politécnica de Madrid, 28040 Madrid (Spain)

    2016-06-15

    A three species one-dimensional kinetic model is presented for a spatially homogeneous weakly ionized plasma subjected to the action of a time varying electric field. Planar geometry is assumed, which means that the plasma evolves in the privileged direction of the field. The energy transmitted to the electric charges is channelized to the neutrals thanks to collisions, a mechanism that influences the plasma dynamics. Charge-charge interactions have been designed as a one-dimensional collision term equivalent to the Landau operator used for fully ionized plasmas. Charge-neutral collisions are modelled by a conservative drift-diffusion operator in the Dougherty's form. The resulting set of coupled integro-differential equations is solved with the stable and robust propagator integral method. This semi–analytical method feasibility accounts for non–linear effects without appealing to linearisation or simplifications, providing conservative physically meaningful solutions even for initial or emerging sharp velocity distribution function profiles. It is found that charge-neutral collisions exert a significant effect since a quite different plasma evolution arises if compared to the collisionless limit. In addition, substantial differences in the system motion are found for constant and temperature dependent collision frequencies cases.

  14. A one-dimensional collisional model for plasma-immersion ion implantation

    International Nuclear Information System (INIS)

    Vahedi, V.; Lieberman, M.A.; Alves, M.V.; Verboncoeur, J.P.; Birdsall, C.K.

    1991-01-01

    Plasma-immersion ion implantation (also known as plasma-source ion implantation) is a process in which a target is immersed in a plasma and a series of large negative-voltage pulses are applied to it to extract ions from the plasma and implant them into the target. A general one-dimensional model is developed to study this process in different coordinate systems for the case in which the pressure of the neutral gas is large enough that the ion motion in the sheath can be assumed to be highly collisional

  15. Efficient two-dimensional compressive sensing in MIMO radar

    Science.gov (United States)

    Shahbazi, Nafiseh; Abbasfar, Aliazam; Jabbarian-Jahromi, Mohammad

    2017-12-01

    Compressive sensing (CS) has been a way to lower sampling rate leading to data reduction for processing in multiple-input multiple-output (MIMO) radar systems. In this paper, we further reduce the computational complexity of a pulse-Doppler collocated MIMO radar by introducing a two-dimensional (2D) compressive sensing. To do so, we first introduce a new 2D formulation for the compressed received signals and then we propose a new measurement matrix design for our 2D compressive sensing model that is based on minimizing the coherence of sensing matrix using gradient descent algorithm. The simulation results show that our proposed 2D measurement matrix design using gradient decent algorithm (2D-MMDGD) has much lower computational complexity compared to one-dimensional (1D) methods while having better performance in comparison with conventional methods such as Gaussian random measurement matrix.

  16. Coherence and population dynamics of chlorophyll excitations in FCP complex: Two-dimensional spectroscopy study

    Energy Technology Data Exchange (ETDEWEB)

    Butkus, Vytautas; Gelzinis, Andrius; Valkunas, Leonas [Department of Theoretical Physics, Faculty of Physics, Vilnius University, Sauletekio Ave. 9-III, 10222 Vilnius (Lithuania); Center for Physical Sciences and Technology, Savanoriu Ave. 231, 02300 Vilnius (Lithuania); Augulis, Ramūnas [Center for Physical Sciences and Technology, Savanoriu Ave. 231, 02300 Vilnius (Lithuania); Gall, Andrew; Robert, Bruno [Institut de Biologie et Technologies de Saclay, Bât 532, Commissariat à l’Energie Atomique Saclay, 91191 Gif sur Yvette (France); Büchel, Claudia [Institut für Molekulare Biowissenschaften, Universität Frankfurt, Max-von-Laue-Straße 9, Frankfurt (Germany); Zigmantas, Donatas [Department of Chemical Physics, Lund University, P.O. Box 124, 22100 Lund (Sweden); Abramavicius, Darius, E-mail: darius.abramavicius@ff.vu.lt [Department of Theoretical Physics, Faculty of Physics, Vilnius University, Sauletekio Ave. 9-III, 10222 Vilnius (Lithuania)

    2015-06-07

    Energy transfer processes and coherent phenomena in the fucoxanthin–chlorophyll protein complex, which is responsible for the light harvesting function in marine algae diatoms, were investigated at 77 K by using two-dimensional electronic spectroscopy. Experiments performed on femtosecond and picosecond timescales led to separation of spectral dynamics, witnessing evolutions of coherence and population states of the system in the spectral region of Q{sub y} transitions of chlorophylls a and c. Analysis of the coherence dynamics allowed us to identify chlorophyll (Chl) a and fucoxanthin intramolecular vibrations dominating over the first few picoseconds. Closer inspection of the spectral region of the Q{sub y} transition of Chl c revealed previously not identified, mutually non-interacting chlorophyll c states participating in femtosecond or picosecond energy transfer to the Chl a molecules. Consideration of separated coherent and incoherent dynamics allowed us to hypothesize the vibrations-assisted coherent energy transfer between Chl c and Chl a and the overall spatial arrangement of chlorophyll molecules.

  17. Liquid structure and freezing of the two-dimensional classical electron fluid

    International Nuclear Information System (INIS)

    Ballone, P.; Pastore, G.; Rovere, M.; Tosi, M.P.

    1984-11-01

    Accurate theoretical results are reported for the pair correlation function of the classical two-dimensional electron liquid with r -1 interactions at strong coupling. The approach involves an evaluation of the bridge diagram corrections to the hypernetted-chain approximation, the role of low dimensionality being evident, relative to the case of the three-dimensional classical plasma, in an enhanced sensitivity to long range correlations. The liquid structure results are utilized in a density-wave theory of first-order freezing into the triangular lattice, the calculated coupling strength at freezing being in reasonable agreement with computer simulation results and with data on electron films on a liquid-He surface. The stability of the triangular electron lattice against deformation into a body-centered rectangular lattice is also discussed. (author)

  18. On the structure of the two-stream instability–complex G-Hamiltonian structure and Krein collisions between positive- and negative-action modes

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Ruili; Liu, Jian; Xiao, Jianyuan [Department of Modern Physics and School of Nuclear Science and Technology, University of Science and Technology of China, Hefei, Anhui 230026 (China); Key Laboratory of Geospace Environment, CAS, Hefei, Anhui 230026 (China); Qin, Hong, E-mail: hongqin@princeton.edu [Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States); Department of Modern Physics and School of Nuclear Science and Technology, University of Science and Technology of China, Hefei, Anhui 230026 (China); Davidson, Ronald C. [Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States)

    2016-07-15

    The two-stream instability is probably the most important elementary example of collective instabilities in plasma physics and beam-plasma systems. For a warm plasma with two charged particle species, the instability diagram of the two-stream instability based on a 1D warm-fluid model exhibits an interesting band structure that has not been explained. We show that the band structure for this instability is the consequence of the Hamiltonian nature of the warm two-fluid system. Interestingly, the Hamiltonian nature manifests as a complex G-Hamiltonian structure in wave-number space, which directly determines the instability diagram. Specifically, it is shown that the boundaries between the stable and unstable regions are locations for Krein collisions between eigenmodes with different Krein signatures. In terms of physics, this rigorously implies that the system is destabilized when a positive-action mode resonates with a negative-action mode, and that this is the only mechanism by which the system can be destabilized. It is anticipated that this physical mechanism of destabilization is valid for other collective instabilities in conservative systems in plasma physics, accelerator physics, and fluid dynamics systems, which admit infinite-dimensional Hamiltonian structures.

  19. Dynamic behavior of polydisperse dust system in cryogenic gas discharge complex plasmas

    NARCIS (Netherlands)

    Antipov, S.N.; Schepers, L.P.T.; Vasiliev, M.M.; Petrov, O.F.

    2016-01-01

    Complex (dusty) plasmas of micron-sized CeO2 polydisperse particles in dc glow discharges at 77 and ∼ 10 K were experimentally investigated. It was obtained that dust structure in cryogenic gas discharge plasma can be a mixture of two fractions (components) with completely different dust ordering

  20. Microstructure in two- and three-dimensional hybrid simulations of perpendicular collisionless shocks

    Czech Academy of Sciences Publication Activity Database

    Burgess, D.; Hellinger, Petr; Gingell, I.; Trávníček, Pavel M.

    2016-01-01

    Roč. 82, č. 4 (2016), 905820401/1-905820401/23 ISSN 0022-3778 Institutional support: RVO:68378289 Keywords : ion-acceleration * numerical simulations * bow shock * electron acceleration * cluster observations * self-reformation * magnetic-field * whistler waves * injection * nonstationarity Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.160, year: 2016 https://www.cambridge.org/core/ journals /journal-of-plasma-physics/article/microstructure-in-two-and-three-dimensional-hybrid-simulations-of-perpendicular-collisionless-shocks/F964EF89FB14A6504A49CFAD54970E2B

  1. Two novel mixed-ligand complexes containing organosulfonate ligands.

    Science.gov (United States)

    Li, Mingtian; Huang, Jun; Zhou, Xuan; Fang, Hua; Ding, Liyun

    2008-07-01

    The structures reported herein, viz. bis(4-aminonaphthalene-1-sulfonato-kappaO)bis(4,5-diazafluoren-9-one-kappa(2)N,N')copper(II), [Cu(C(10)H(8)NO(3)S)(2)(C(11)H(6)N(2)O)(2)], (I), and poly[[[diaquacadmium(II)]-bis(mu-4-aminonaphthalene-1-sulfonato)-kappa(2)O:N;kappa(2)N:O] dihydrate], {[Cd(C(10)H(8)NO(3)S)(2)(H(2)O)(2)].2H(2)O}(n), (II), are rare examples of sulfonate-containing complexes where the anion does not fulfill a passive charge-balancing role, but takes an active part in coordination as a monodentate and/or bridging ligand. Monomeric complex (I) possesses a crystallographic inversion center at the Cu(II) atom, and the asymmetric unit contains one-half of a Cu atom, one complete 4-aminonaphthalene-1-sulfonate (ans) ligand and one 4,5-diazafluoren-9-one (DAFO) ligand. The Cu(II) atom has an elongated distorted octahedral coordination geometry formed by two O atoms from two monodentate ans ligands and by four N atoms from two DAFO molecules. Complex (II) is polymeric and its crystal structure is built up by one-dimensional chains and solvent water molecules. Here also the cation (a Cd(II) atom) lies on a crystallographic inversion center and adopts a slightly distorted octahedral geometry. Each ans anion serves as a bridging ligand linking two Cd(II) atoms into one-dimensional infinite chains along the [010] direction, with each Cd(II) center coordinated by four ans ligands via O and N atoms and by two aqua ligands. In both structures, there are significant pi-pi stacking interactions between adjacent ligands and hydrogen bonds contribute to the formation of two- and three-dimensional networks.

  2. Two-dimensional LIF measurements of humidity and OH density resulting from evaporated water from a wet surface in plasma for medical use

    International Nuclear Information System (INIS)

    Yagi, Ippei; Ono, Ryo; Oda, Tetsuji; Takaki, Koichi

    2015-01-01

    In plasma medicine, plasma is applied to a wet surface and is often accompanied by dry-gas flow. The dry-gas flow affects water evaporation from the wet surface and influences production of reactive species derived from water vapor, such as OH radicals. In this study, the effect of the dry-gas flow on two-dimensional distributions of humidity and OH radical density are examined by measuring them using laser-induced fluorescence (LIF). First, humidity is measured when nitrogen flows from a quartz tube of 4 mm inner diameter onto distilled water and agar media from 5 mm distance. NO gas is added to the nitrogen as a tracer and humidity is obtained from the quenching rate of NO molecules measured using LIF. This measurement has a spatial resolution of 0.2 mm 3 and a temporal resolution of less than 220 ns. The two-dimensional humidity distribution shows that the dry-gas flow pushes away water vapor evaporating from the wet surface. As a result, a low-humidity region is formed near the quartz tube nozzle and a high-humidity region is formed near the wet surface. The thickness of the low-humidity region reduces with increasing gas flow rate. It is 0.1–0.5 mm for the flow rate of higher than 0.3 l min −1 . Next, the OH density is measured when a nanosecond pulsed streamer discharge is applied to a distilled water surface with dry-air flow. The OH density decreases with increasing gas flow rate due to decreased humidity. When the flow rate is lower than 0.1 l min −1 , the OH distribution is approximately uniform in the plasma region, while the humidity distribution shows a large gradient. The importance of the thin high-humidity region on the flux of reactive species onto the wet surface is discussed. (paper)

  3. Verification of frequency scaling laws for capacitive radio-frequency discharges using two-dimensional simulations

    International Nuclear Information System (INIS)

    Vahedi, V.; Birdsall, C.K.; Lieberman, M.A.; DiPeso, G.; Rognlien, T.D.

    1993-01-01

    Weakly ionized processing plasmas are studied in two dimensions using a bounded particle-in-cell (PIC) simulation code with a Monte Carlo collision (MCC) package. The MCC package models the collisions between charged and neutral particles, which are needed to obtain a self-sustained plasma and the proper electron and ion energy loss mechanisms. A two-dimensional capacitive radio-frequency (rf) discharge is investigated in detail. Simple frequency scaling laws for predicting the behavior of some plasma parameters are derived and then compared with simulation results, finding good agreements. It is found that as the drive frequency increases, the sheath width decreases, and the bulk plasma becomes more uniform, leading to a reduction of the ion angular spread at the target and an improvement of ion dose uniformity at the driven electrode

  4. Quantum trajectories in complex space: One-dimensional stationary scattering problems

    International Nuclear Information System (INIS)

    Chou, C.-C.; Wyatt, Robert E.

    2008-01-01

    One-dimensional time-independent scattering problems are investigated in the framework of the quantum Hamilton-Jacobi formalism. The equation for the local approximate quantum trajectories near the stagnation point of the quantum momentum function is derived, and the first derivative of the quantum momentum function is related to the local structure of quantum trajectories. Exact complex quantum trajectories are determined for two examples by numerically integrating the equations of motion. For the soft potential step, some particles penetrate into the nonclassical region, and then turn back to the reflection region. For the barrier scattering problem, quantum trajectories may spiral into the attractors or from the repellers in the barrier region. Although the classical potentials extended to complex space show different pole structures for each problem, the quantum potentials present the same second-order pole structure in the reflection region. This paper not only analyzes complex quantum trajectories and the total potentials for these examples but also demonstrates general properties and similar structures of the complex quantum trajectories and the quantum potentials for one-dimensional time-independent scattering problems

  5. Dispersion relation of electromagnetic waves in one-dimensional plasma photonic crystals

    International Nuclear Information System (INIS)

    Hojo, Hitoshi; Mase, Atsushi

    2004-01-01

    The dispersion relation of electromagnetic waves in one-dimensional plasma photonic crystals is studied. The plasma photonic crystal is a periodic array composed of alternating thin plasma and dielectric material. The dispersion relation is obtained by solving a Maxwell wave equation using a method analogous to Kronig-Penny's problem in quantum mechanics, and it is found that the frequency gap and cut-off appear in the dispersion relation. The frequency gap is shown to become larger with the increase of the plasma density as well as plasma width. (author)

  6. High-throughput determination of vancomycin in human plasma by a cost-effective system of two-dimensional liquid chromatography.

    Science.gov (United States)

    Sheng, Yanghao; Zhou, Boting

    2017-05-26

    Therapeutic drug monitoring (TDM) is one of the most important services of clinical laboratories. Two main techniques are commonly used: the immunoassay and chromatography method. We have developed a cost-effective system of two-dimensional liquid chromatography with ultraviolet detection (2D-LC-UV) for high-throughput determination of vancomycin in human plasma that combines the automation and low start-up costs of the immunoassay with the high selectivity and sensitivity of the liquid chromatography coupled with mass spectrometric detection without incurring their disadvantages, achieving high cost-effectiveness. This 2D-LC system offers a large volume injection to provide sufficient sensitivity and uses simulated gradient peak compression technology to control peak broadening and to improve peak shape. A middle column was added to reduce the analysis cycle time and make it suitable for high-throughput routine clinical assays. The analysis cycle time was 4min and the peak width was 0.8min. Compared with other chromatographic methods that have been developed, the analysis cycle time and peak width for vancomycin was reduced significantly. The lower limit of quantification was 0.20μg/mL for vancomycin, which is the same as certain LC-MS/MS methods that have been recently developed and validated. The method is rapid, automated, and low-cost and has high selectivity and sensitivity for the quantification of vancomycin in human plasma, thus making it well-suited for use in hospital clinical laboratories. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Image Encryption Scheme Based on Balanced Two-Dimensional Cellular Automata

    Directory of Open Access Journals (Sweden)

    Xiaoyan Zhang

    2013-01-01

    Full Text Available Cellular automata (CA are simple models of computation which exhibit fascinatingly complex behavior. Due to the universality of CA model, it has been widely applied in traditional cryptography and image processing. The aim of this paper is to present a new image encryption scheme based on balanced two-dimensional cellular automata. In this scheme, a random image with the same size of the plain image to be encrypted is first generated by a pseudo-random number generator with a seed. Then, the random image is evoluted alternately with two balanced two-dimensional CA rules. At last, the cipher image is obtained by operating bitwise XOR on the final evolution image and the plain image. This proposed scheme possesses some advantages such as very large key space, high randomness, complex cryptographic structure, and pretty fast encryption/decryption speed. Simulation results obtained from some classical images at the USC-SIPI database demonstrate the strong performance of the proposed image encryption scheme.

  8. Pattern formation in two-dimensional square-shoulder systems

    International Nuclear Information System (INIS)

    Fornleitner, Julia; Kahl, Gerhard

    2010-01-01

    Using a highly efficient and reliable optimization tool that is based on ideas of genetic algorithms, we have systematically studied the pattern formation of the two-dimensional square-shoulder system. An overwhelming wealth of complex ordered equilibrium structures emerge from this investigation as we vary the shoulder width. With increasing pressure three structural archetypes could be identified: cluster lattices, where clusters of particles occupy the sites of distorted hexagonal lattices, lane formation, and compact particle arrangements with high coordination numbers. The internal complexity of these structures increases with increasing shoulder width.

  9. Pattern formation in two-dimensional square-shoulder systems

    Energy Technology Data Exchange (ETDEWEB)

    Fornleitner, Julia [Institut fuer Festkoerperforschung, Forschungsszentrum Juelich, D-52425 Juelich (Germany); Kahl, Gerhard, E-mail: fornleitner@cmt.tuwien.ac.a [Institut fuer Theoretische Physik and Centre for Computational Materials Science (CMS), Technische Universitaet Wien, Wiedner Hauptstrasse 8-10, A-1040 Wien (Austria)

    2010-03-17

    Using a highly efficient and reliable optimization tool that is based on ideas of genetic algorithms, we have systematically studied the pattern formation of the two-dimensional square-shoulder system. An overwhelming wealth of complex ordered equilibrium structures emerge from this investigation as we vary the shoulder width. With increasing pressure three structural archetypes could be identified: cluster lattices, where clusters of particles occupy the sites of distorted hexagonal lattices, lane formation, and compact particle arrangements with high coordination numbers. The internal complexity of these structures increases with increasing shoulder width.

  10. On improved understanding of plasma-chemical processes in complex low-temperature plasmas

    Science.gov (United States)

    Röpcke, Jürgen; Loffhagen, Detlef; von Wahl, Eric; Nave, Andy S. C.; Hamann, Stephan; van Helden, Jean-Piere H.; Lang, Norbert; Kersten, Holger

    2018-05-01

    Over the last years, chemical sensing using optical emission spectroscopy (OES) in the visible spectral range has been combined with methods of mid infrared laser absorption spectroscopy (MIR-LAS) in the molecular fingerprint region from 3 to 20 μm, which contains strong rotational-vibrational absorption bands of a large variety of gaseous species. This optical approach established powerful in situ diagnostic tools to study plasma-chemical processes of complex low-temperature plasmas. The methods of MIR-LAS enable to detect stable and transient molecular species in ground and excited states and to measure the concentrations and temperatures of reactive species in plasmas. Since kinetic processes are inherent to discharges ignited in molecular gases, high time resolution on sub-second timescales is frequently desired for fundamental studies as well as for process monitoring in applied research and industry. In addition to high sensitivity and good temporal resolution, the capacity for broad spectral coverage enabling multicomponent detection is further expanding the use of OES and MIR-LAS techniques. Based on selected examples, this paper reports on recent achievements in the understanding of complex low-temperature plasmas. Recently, a link with chemical modeling of the plasma has been provided, which is the ultimate objective for a better understanding of the chemical and reaction kinetic processes occurring in the plasma. Contribution to the Topical Issue "Fundamentals of Complex Plasmas", edited by Jürgen Meichsner, Michael Bonitz, Holger Fehske, Alexander Piel.

  11. Terahertz response of two-dimensional charge carrier systems in GaAs-based heterostructures; Terahertz-Antwort von zweidimensionalen Ladungstraegersystemen in GaAs-basierten Heterostrukturen

    Energy Technology Data Exchange (ETDEWEB)

    Grunwald, Torben

    2009-12-17

    This thesis deals with the THz response of two-dimensional charge carrier systems in different semiconductor heterostructures under varying conditions. The utilized spectrometer is suitable for time-resolved optical pump - THz probe experiments, as well as for optical pump-probe experiments in the near infrared for identical conditions. It allows the investigation of the transverse dielectric function of both, a (GaIn)As/GaAs quantum well and a two-dimensional electron gas in a GaAs-based heterostructure. First, the THz response of an electron-hole plasma is examined for different carrier densities. The plasma is generated by interband transitions in a (GaIn)As/GaAs quantum well. The measured transverse dielectric function reveals that the plasma behaves in accordance with the classical Drude oscillator model. It also conforms to the microscopic theory of the THz response of corresponding many-body systems. Evidence of a plasma resonance in the negative imaginary part of the inverse dielectric function is found. The squared peak frequency of the resonance is proportional to the carrier density of the plasma. This behavior corresponds to the plasma frequency of a three-dimensional plasma. Overall, it can be shown that the transverse THz response of a two-dimensional electron-hole plasma behaves like the response of a three-dimensional plasma. Therefore, the transversal THz response of an electron-hole plasma seems to be independent of the dimension of the charge carrier system. Secondly, the behavior of the quantum well for a 1s-exciton dominated carrier system is investigated. A good agreement between experiment and microscopic theory is obtained for the dielectric function. The negative imaginary part of the inverse dielectric function shows a resonance at the intraexcitonic 1s-2p transition frequency, even in weakly excited excitonic systems. Increasing the carrier density leads to a plasma-like behavior of the system. However, in these densities a significant

  12. Two-dimensional divertor modeling and scaling laws

    International Nuclear Information System (INIS)

    Catto, P.J.; Connor, J.W.; Knoll, D.A.

    1996-01-01

    Two-dimensional numerical models of divertors contain large numbers of dimensionless parameters that must be varied to investigate all operating regimes of interest. To simplify the task and gain insight into divertor operation, we employ similarity techniques to investigate whether model systems of equations plus boundary conditions in the steady state admit scaling transformations that lead to useful divertor similarity scaling laws. A short mean free path neutral-plasma model of the divertor region below the x-point is adopted in which all perpendicular transport is due to the neutrals. We illustrate how the results can be used to benchmark large computer simulations by employing a modified version of UEDGE which contains a neutral fluid model. (orig.)

  13. A primer on complex systems with applications to astrophysical and laboratory plasmas

    CERN Document Server

    Sánchez, Raúl

    2018-01-01

    The purpose of this book is to illustrate the fundamental concepts of complexity and complex behavior and the best methods to characterize this behavior by means of their applications to some current research topics from within the fields of fusion, earth and solar plasmas. In this sense, it is a departure from the many books already available that discuss general features of complexity. The book is divided in two parts. In the first part the most important properties and features of complex systems are introduced, discussed and illustrated. The second part discusses several instances of possible complex phenomena in magnetized plasmas and some of the analysis tools that were introduced in the first part are used to characterize the dynamics in these systems. A list of problems is proposed at the end of each chapter. This book is intended for graduate and post-graduate students with a solid college background in mathematics and classical physics, who intend to work in the field of plasma physics and, in parti...

  14. Biderivations of finite dimensional complex simple Lie algebras

    OpenAIRE

    Tang, Xiaomin

    2016-01-01

    In this paper, we prove that a biderivation of a finite dimensional complex simple Lie algebra without the restriction of skewsymmetric is inner. As an application, the biderivation of a general linear Lie algebra is presented. In particular, we find a class of a non-inner and non-skewsymmetric biderivations. Furthermore, we also get the forms of linear commuting maps on the finite dimensional complex simple Lie algebra or general linear Lie algebra.

  15. Stabilisation of a three-dimensional boundary layer by base-flow manipulation using plasma actuators

    International Nuclear Information System (INIS)

    Dörr, P C; Kloker, M J

    2015-01-01

    The applicability of dielectric barrier discharge plasma actuators for controlling the crossflow-vortex-induced laminar breakdown in a three-dimensional swept-wing-type boundary-layer flow is investigated using direct numerical simulation. Similar to the classical application of suction at the wall the aim is to modify the quasi two-dimensional base flow and to weaken primary crossflow (CF) instability, mainly due to a reduction of the basic CF. Not only localised volumetric forcing by plasma actuators but also CF counter-blowing and spots with a moving wall are investigated to identify effective fundamental mechanisms. It is found that counter blowing always results in partial blockage of the flow and eventually increased CF velocity, whereas moving-wall spots can slightly reduce the CF and the amplitude of crossflow vortices. Using discrete volumetric forcing a significant attenuation even of finite-amplitude crossflow vortices and thus a distinct transition delay is achieved. (paper)

  16. A two-dimensional nodal model with turbulent effects for the synthesis of Si nano-particles by inductively coupled thermal plasmas

    International Nuclear Information System (INIS)

    Colombo, V; Ghedini, E; Gherardi, M; Sanibondi, P; Shigeta, M

    2012-01-01

    Nano-particle synthesis by means of inductively coupled plasma torches is a material process of large technological interest. Numerous parameters are involved in the optimization of this process; hence the development of numerical models for the prediction of thermal and magneto-fluid dynamics fields, precursor powder trajectories and thermal history, as well as nano-particle formation and growth, is necessary for the up-scaling of these devices from laboratory batch production to an industrial continuous process. In this work, a two-dimensional (2D) discrete-type model (nodal model) for the analysis of nano-powder nucleation and growth is presented, taking into account convection, diffusion and turbulent effects on particle formation. Discrete-type models feature high precision and reveal a great deal of information useful for clarifying the nano-particle formation process. Using Si as the precursor material, 2D simulations of a nano-particle synthesis RF plasma apparatus with a reaction chamber are carried out. Good agreement is found when comparing results obtained with this model with those coming from a well-established nucleation-coupled moment method. Moreover, the extended amount of obtainable information that characterizes the nodal model is underlined. (paper)

  17. Low-dimensional model of resistive interchange convection in magnetized plasma

    International Nuclear Information System (INIS)

    Bazdenkov, S.; Sato, Tetsuya

    1997-09-01

    Self-organization and generation of large shear flow component in turbulent resistive interchange convection in magnetized plasma is considered. The effect of plasma density-electrostatic potential coupling via the inertialess electron dynamics along the magnetic field is shown to play significant role in the onset of shear component. The results of large-scale numerical simulation and low-dimensional (reduced) model are presented and compared. (author)

  18. Complete photonic band gaps and tunable self-collimation in the two-dimensional plasma photonic crystals with a new structure

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Hai-Feng, E-mail: hanlor@163.com [Key Laboratory of Radar Imaging and Microwave Photonics (Nanjing University of Aeronautics and Astronautics), Ministry of Education, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Nanjing Artillery Academy, Nanjing 211132 (China); Ding, Guo-Wen; Li, Hai-Ming; Liu, Shao-Bin [Key Laboratory of Radar Imaging and Microwave Photonics (Nanjing University of Aeronautics and Astronautics), Ministry of Education, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China)

    2015-02-15

    In this paper, the properties of complete photonic band gaps (CPBGs) and tunable self-collimation in two-dimensional plasma photonic crystals (2D PPCs) with a new structure in square lattices, whose dielectric fillers (GaAs) are inserted into homogeneous and nomagnetized plasma background are theoretically investigated by a modified plane wave expansion (PWE) method with a novel technique. The novel PWE method can be utilized to compute the dispersion curves of 2D PPCs with arbitrary-shaped cross section in any lattices. As a comparison, CPBGs of PPCs for four different configurations are numerically calculated. The computed results show that the proposed design has the advantages of achieving the larger CPBGs compared to the other three configurations. The influences of geometric parameters of filled unit cell and plasma frequency on the properties of CPBGs are studied in detail. The calculated results demonstrate that CPBGs of the proposed 2D PPCs can be easily engineered by changing those parameters, and the larger CPBGs also can be obtained by optimization. The self-collimation in such 2D PPCs also is discussed in theory under TM wave. The theoretical simulations reveal that the self-collimation phenomena can be found in the TM bands, and both the frequency range of self-collimation and the equifrequency surface contours can be tuned by the parameters as mentioned above. It means that the frequency range and direction of electromagnetic wave can be manipulated by designing, as it propagates in the proposed PPCs without diffraction. Those results can hold promise for designing the tunable applications based on the proposed PPCs.

  19. Complete photonic band gaps and tunable self-collimation in the two-dimensional plasma photonic crystals with a new structure

    International Nuclear Information System (INIS)

    Zhang, Hai-Feng; Ding, Guo-Wen; Li, Hai-Ming; Liu, Shao-Bin

    2015-01-01

    In this paper, the properties of complete photonic band gaps (CPBGs) and tunable self-collimation in two-dimensional plasma photonic crystals (2D PPCs) with a new structure in square lattices, whose dielectric fillers (GaAs) are inserted into homogeneous and nomagnetized plasma background are theoretically investigated by a modified plane wave expansion (PWE) method with a novel technique. The novel PWE method can be utilized to compute the dispersion curves of 2D PPCs with arbitrary-shaped cross section in any lattices. As a comparison, CPBGs of PPCs for four different configurations are numerically calculated. The computed results show that the proposed design has the advantages of achieving the larger CPBGs compared to the other three configurations. The influences of geometric parameters of filled unit cell and plasma frequency on the properties of CPBGs are studied in detail. The calculated results demonstrate that CPBGs of the proposed 2D PPCs can be easily engineered by changing those parameters, and the larger CPBGs also can be obtained by optimization. The self-collimation in such 2D PPCs also is discussed in theory under TM wave. The theoretical simulations reveal that the self-collimation phenomena can be found in the TM bands, and both the frequency range of self-collimation and the equifrequency surface contours can be tuned by the parameters as mentioned above. It means that the frequency range and direction of electromagnetic wave can be manipulated by designing, as it propagates in the proposed PPCs without diffraction. Those results can hold promise for designing the tunable applications based on the proposed PPCs

  20. Equivalence of two-dimensional gravities

    International Nuclear Information System (INIS)

    Mohammedi, N.

    1990-01-01

    The authors find the relationship between the Jackiw-Teitelboim model of two-dimensional gravity and the SL(2,R) induced gravity. These are shown to be related to a two-dimensional gauge theory obtained by dimensionally reducing the Chern-Simons action of the 2 + 1 dimensional gravity. The authors present an explicit solution to the equations of motion of the auxiliary field of the Jackiw-Teitelboim model in the light-cone gauge. A renormalization of the cosmological constant is also given

  1. Potential formation in a one-dimensional bounded plasma system containing a two-electron temperature plasma: Kinetic model and PIC simulation

    International Nuclear Information System (INIS)

    Gyergyek, T.; Jurcic-Zlobec, B.; Cercek, M.

    2008-01-01

    Potential formation in a bounded plasma system that contains electrons with a two-temperature velocity distribution and is terminated by a floating, electron emitting electrode (collector) is studied by a one-dimensional kinetic model. A method on how to determine the boundary conditions at the collector for the numerical solution of the Poisson equation is presented. The difference between the regular and the irregular numerical solutions of the Poisson equation is explained. The regular numerical solution of the Poisson equation fulfills the boundary conditions at the source and can be computed for any distance from the collector. The irregular solution does not fulfill the source boundary conditions and the computation breaks down at some distance from the collector. An excellent agreement of the values of the potential at the inflection point found from the numerical solution of the Poisson equation with the values predicted by the analytical model is obtained. Potential, electric field, and particle density profiles found by the numerical solution of the Poisson equation are compared to the profiles obtained with the particle in cell computer simulation. A very good quantitative agreement of the potential and electric field profiles is obtained. For certain values of the parameters the analytical model predicts three possible values of the potential at the inflection point. In such cases always only one of the corresponding numerical solutions of the Poisson equation is regular, while the other two are irregular. The regular numerical solution of the Poisson equation always corresponds to the solution of the model that predicts the largest ion flux to the collector

  2. Deterministic transfer of two-dimensional materials by all-dry viscoelastic stamping

    International Nuclear Information System (INIS)

    Castellanos-Gomez, Andres; Buscema, Michele; Molenaar, Rianda; Singh, Vibhor; Janssen, Laurens; Van der Zant, Herre S J; Steele, Gary A

    2014-01-01

    The deterministic transfer of two-dimensional crystals constitutes a crucial step towards the fabrication of heterostructures based on the artificial stacking of two-dimensional materials. Moreover, controlling the positioning of two-dimensional crystals facilitates their integration in complex devices, which enables the exploration of novel applications and the discovery of new phenomena in these materials. To date, deterministic transfer methods rely on the use of sacrificial polymer layers and wet chemistry to some extent. Here, we develop an all-dry transfer method that relies on viscoelastic stamps and does not employ any wet chemistry step. This is found to be very advantageous to freely suspend these materials as there are no capillary forces involved in the process. Moreover, the whole fabrication process is quick, efficient, clean and it can be performed with high yield. (letter)

  3. Two-dimensional metamaterial optics

    International Nuclear Information System (INIS)

    Smolyaninov, I I

    2010-01-01

    While three-dimensional photonic metamaterials are difficult to fabricate, many new concepts and ideas in the metamaterial optics can be realized in two spatial dimensions using planar optics of surface plasmon polaritons. In this paper we review recent progress in this direction. Two-dimensional photonic crystals, hyperbolic metamaterials, and plasmonic focusing devices are demonstrated and used in novel microscopy and waveguiding schemes

  4. Multi-dimensional instability of electrostatic solitary structures in magnetized nonthermal dusty plasmas

    International Nuclear Information System (INIS)

    Mamun, A.A.; Russel, S.M.; Mendoza-Briceno, C.A.; Alam, M.N.; Datta, T.K.; Das, A.K.

    1999-05-01

    A rigorous theoretical investigation has been made of multi-dimensional instability of obliquely propagating electrostatic solitary structures in a hot magnetized nonthermal dusty plasma which consists of a negatively charged hot dust fluid, Boltzmann distributed electrons, and nonthermally distributed ions. The Zakharov-Kuznetsov equation for the electrostatic solitary structures that exist in such a dusty plasma system is derived by the reductive perturbation method. The multi-dimensional instability of these solitary waves is also studied by the small-k (long wavelength plane wave) perturbation expansion method. The nature of these solitary structures, the instability criterion, and their growth rate depending on dust-temperature, external magnetic field, and obliqueness are discussed. The implications of these results to some space and astrophysical dusty plasma situations are briefly mentioned. (author)

  5. Inorganic anion-dependent assembly of zero-, one-, two- and three-dimensional Cu(II)/Ag(I) complexes under the guidance of the HSAB theory: Synthesis, structure, and magnetic property

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yaru; Xing, Zhiyan [School of Science, North University of China, Taiyuan, Shanxi 030051 (China); Zhang, Xiao [MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150080 (China); Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education, School of Chemistry and Materials Science, Heilongjiang University, Harbin 150080 PR China (China); Liang, Guorui [School of Science, North University of China, Taiyuan, Shanxi 030051 (China)

    2017-02-15

    To systematically explore the influence of inorganic anions on building coordination complexes, five novel complexes based on 1-(benzotriazole-1-methyl)−2-propylimidazole (bpmi), [Cu(bpmi){sub 2}(Ac){sub 2}]·H{sub 2}O (1), [Cu(bpmi){sub 2}(H{sub 2}O){sub 2}]·2NO{sub 3}·2H{sub 2}O (2), [Cu(bpmi)(N{sub 3}){sub 2}] (3), [Ag(bpmi)(NO{sub 3})] (4) and [Cu{sub 3}(bpmi){sub 2}(SCN){sub 4}(DMF)] (5) (Ac{sup −}=CH{sub 3}COO{sup −}, DMF=N,N-Dimethylformamide) are synthesized through rationally introducing Cu(II) salts and Ag(I) salt with different inorganic anions. X-ray single-crystal analyses reveal that these complexes show interesting structural features from mononuclear (1), one-dimensional (2 and 3), two-dimensional (4) to three-dimensional (5) under the influence of inorganic anions with different basicities. The structural variation can be explained by the hard-soft-acid-base (HSAB) theory. Magnetic susceptibility measurement indicates that complex 3 exhibits an antiferromagnetic coupling between adjacent Cu(II) ions. - Graphical abstract: Five new Cu(II)/Ag(I) complexes show interesting structural features from mononuclear, one-dimension, two-dimension to three-dimension under the influence of inorganic anions. The structural variation can be explained by the HSAB theory. - Highlights: • Five inorganic anion-dependent complexes are synthesized. • Structural variation can be explained by the hard-soft-acid-base (HSAB) theory. • The magnetic property of complex has been studied.

  6. Two dimensional gel electrophoresis using narrow pH 3-5.6 immobilised pH gradient strips identifies potential novel disease biomarkers in plasma or serum

    OpenAIRE

    sprotocols

    2015-01-01

    Authors: Bevin Gangadharan & Nicole Zitzmann ### Abstract Two-dimensional gel electrophoresis (2-DE) is a protein separation technique often used to separate plasma or serum proteins in an attempt to identify novel biomarkers. This protocol describes how to run 2-DE gels using narrow pH 3-5.6 immobilised pH gradient strips to separate 2 mg of serum proteins. pH 3-6 ampholytes are used to enhance the solubility of proteins in this pH range before the serum proteins are separated in the...

  7. Particle-in-cell plasma simulations of the modified two-stream instability

    Directory of Open Access Journals (Sweden)

    K. Schlegel

    1994-08-01

    Full Text Available We model the modified two-stream plasma instability occurring in the ionospheric E-region using a 2.5-dimensional particle-in-cell code. Compared to previous similar work we concentrate on simulated quantities that can easily be measured in the real ionosphere by coherent radars or rockets, such as the Doppler velocity, the backscattered power, backscattered spectra, aspect angle behaviour and electron temperature enhancement. Despite using a relatively small simulation model, we obtain remarkably good agreement between actual observed and simulated plasma parameters. The advantage of such a small system is that we were able to perform (other than in previous related work many simulation runs with different sets of input parameters, thus studying the unstable plasma under various conditions.

  8. A One-Dimensional Particle-in-Cell Model of Plasma Build-Up in Vacuum Arcs

    CERN Document Server

    Timko, H; Kovermann, J; Taborelli, M; Nordlund, K; Descoeudres, A; Schneider, R; Calatroni, S; Matyash, K; Wuensch, W; Hansen, A; Grudiev, A

    2011-01-01

    Understanding the mechanism of plasma build-up in vacuum arcs is essential in many fields of physics. A one-dimensional particle-in-cell computer simulation model is presented, which models the plasma developing from a field emitter tip under electrical breakdown conditions, taking into account the relevant physical phenomena. As a starting point, only an external electric field and an initial enhancement factor of the tip are assumed. General requirements for plasma formation have been identified and formulated in terms of the initial local field and a critical neutral density. The dependence of plasma build-up on tip melting current, the evaporation rate of neutrals and external circuit time constant has been investigated for copper and simulations imply that arcing involves melting currents around 0.5-1 A/mu m(2),evaporation of neutrals to electron field emission ratios in the regime 0.01 - 0.05, plasma build-up timescales in the order of similar to 1 - 10 ns and two different regimes depending on initial ...

  9. Kinetic theory of nonlinear transport phenomena in complex plasmas

    International Nuclear Information System (INIS)

    Mishra, S. K.; Sodha, M. S.

    2013-01-01

    In contrast to the prevalent use of the phenomenological theory of transport phenomena, a number of transport properties of complex plasmas have been evaluated by using appropriate expressions, available from the kinetic theory, which are based on Boltzmann's transfer equation; in particular, the energy dependence of the electron collision frequency has been taken into account. Following the recent trend, the number and energy balance of all the constituents of the complex plasma and the charge balance on the particles is accounted for; the Ohmic loss has also been included in the energy balance of the electrons. The charging kinetics for the complex plasma comprising of uniformly dispersed dust particles, characterized by (i) uniform size and (ii) the Mathis, Rumpl, and Nordsieck power law of size distribution has been developed. Using appropriate expressions for the transport parameters based on the kinetic theory, the system of equations has been solved to investigate the parametric dependence of the complex plasma transport properties on the applied electric field and other plasma parameters; the results are graphically illustrated.

  10. Dynamic three-dimensional display of common congenital cardiac defects from reconstruction of two-dimensional echocardiographic images.

    Science.gov (United States)

    Hsieh, K S; Lin, C C; Liu, W S; Chen, F L

    1996-01-01

    Two-dimensional echocardiography had long been a standard diagnostic modality for congenital heart disease. Further attempts of three-dimensional reconstruction using two-dimensional echocardiographic images to visualize stereotypic structure of cardiac lesions have been successful only recently. So far only very few studies have been done to display three-dimensional anatomy of the heart through two-dimensional image acquisition because such complex procedures were involved. This study introduced a recently developed image acquisition and processing system for dynamic three-dimensional visualization of various congenital cardiac lesions. From December 1994 to April 1995, 35 cases were selected in the Echo Laboratory here from about 3000 Echo examinations completed. Each image was acquired on-line with specially designed high resolution image grazmber with EKG and respiratory gating technique. Off-line image processing using a window-architectured interactive software package includes construction of 2-D ehcocardiographic pixel to 3-D "voxel" with conversion of orthogonal to rotatory axial system, interpolation, extraction of region of interest, segmentation, shading and, finally, 3D rendering. Three-dimensional anatomy of various congenital cardiac defects was shown, including four cases with ventricular septal defects, two cases with atrial septal defects, and two cases with aortic stenosis. Dynamic reconstruction of a "beating heart" is recorded as vedio tape with video interface. The potential application of 3D display of the reconstruction from 2D echocardiographic images for the diagnosis of various congenital heart defects has been shown. The 3D display was able to improve the diagnostic ability of echocardiography, and clear-cut display of the various congenital cardiac defects and vavular stenosis could be demonstrated. Reinforcement of current techniques will expand future application of 3D display of conventional 2D images.

  11. Visualization of Excitonic Structure in the Fenna-Matthews-Olson Photosynthetic Complex by Polarization-Dependent Two-Dimensional Electronic Spectroscopy

    International Nuclear Information System (INIS)

    Fleming, Graham; Read, Elizabeth L.; Schlau-Cohen, Gabriela S.; Engel, Gregory S.; Wen, Jianzhong; Blankenship, Robert E.; Fleming, Graham R.

    2008-01-01

    Photosynthetic light-harvesting proceeds by the collection and highly efficient transfer of energy through a network of pigment-protein complexes. Inter-chromophore electronic couplings and interactions between pigments and the surrounding protein determine energy levels of excitonic states and dictate the mechanism of energy flow. The excitonic structure (orientation of excitonic transition dipoles) of pigment-protein complexes is generally deduced indirectly from x-ray crystallography in combination with predictions of transition energies and couplings in the chromophore site basis. Here, we demonstrate that coarse-grained excitonic structural information in the form of projection angles between transition dipole moments can be obtained from polarization-dependent two-dimensional electronic spectroscopy of an isotropic sample, particularly when the nonrephasing or free polarization decay signal rather than the photon echo signal is considered. The method provides an experimental link between atomic and electronic structure and accesses dynamical information with femtosecond time resolution. In an investigation of the Fenna-Matthews-Olson complex from green sulfur bacteria, energy transfer connecting two particular exciton states in the protein is isolated as being the primary contributor to a cross peak in the nonrephasing 2D spectrum at 400 fs under a specific sequence of polarized excitation pulses. The results suggest the possibility of designing experiments using combinations of tailored polarization sequences to separate and monitor individual relaxation pathways

  12. Strain-engineered growth of two-dimensional materials.

    Science.gov (United States)

    Ahn, Geun Ho; Amani, Matin; Rasool, Haider; Lien, Der-Hsien; Mastandrea, James P; Ager Iii, Joel W; Dubey, Madan; Chrzan, Daryl C; Minor, Andrew M; Javey, Ali

    2017-09-20

    The application of strain to semiconductors allows for controlled modification of their band structure. This principle is employed for the manufacturing of devices ranging from high-performance transistors to solid-state lasers. Traditionally, strain is typically achieved via growth on lattice-mismatched substrates. For two-dimensional (2D) semiconductors, this is not feasible as they typically do not interact epitaxially with the substrate. Here, we demonstrate controlled strain engineering of 2D semiconductors during synthesis by utilizing the thermal coefficient of expansion mismatch between the substrate and semiconductor. Using WSe 2 as a model system, we demonstrate stable built-in strains ranging from 1% tensile to 0.2% compressive on substrates with different thermal coefficient of expansion. Consequently, we observe a dramatic modulation of the band structure, manifested by a strain-driven indirect-to-direct bandgap transition and brightening of the dark exciton in bilayer and monolayer WSe 2 , respectively. The growth method developed here should enable flexibility in design of more sophisticated devices based on 2D materials.Strain engineering is an essential tool for modifying local electronic properties in silicon-based electronics. Here, Ahn et al. demonstrate control of biaxial strain in two-dimensional materials based on the growth substrate, enabling more complex low-dimensional electronics.

  13. Proteomic analysis of plasma proteins in diabetic retinopathy patients by two dimensional electrophoresis and MALDI-Tof-MS.

    Science.gov (United States)

    Gopalakrishnan, Vidhya; Purushothaman, Parthiban; Bhaskar, Anusha

    2015-01-01

    Diabetic retinopathy is a highly specific vascular complication of diabetes mellitus and progresses from mild non-proliferative abnormalities characterized by increased vascular permeability to moderate and severe proliferative diabetic retinopathy characterized by the growth of blood vessels on the retina. The aim of the study was to identify the differentially expressed proteins in diabetic retinopathy using two-dimensional electrophoresis. Blood sample was drawn from subjects with diabetes mellitus (without retinopathy) who served as controls and patients with diabetic retinopathy in tubes containing EDTA as anticoagulant. Albumin and immunoglobulin IgG collectively removed to enrich proteins of lower abundance. 2de was carried out to see if there are any differentially expressed proteins. Approximately 48 and 61 spots were identified in control and diabetic retinopathy respectively, of which three protein spots RBP1 (retinol-binding protein 1), NUD10 (Diphosphoinositol polyphosphohydrolase 3 alpha), NGB (neuroglobin) were down regulated and HBG2 (hemoglobin) and BY55 (CD 160 antigen) were upregulated in diabetic retinopathy. These five protein spots were excised and were subjected to in-gel tryptic digestion, and their identities were determined by ultraflex MALDI-TOF-MS. We report a comprehensive patient-based plasma proteomic approach to the identification of potential biomarkers for diabetic retinopathy screening and detection. We identified 5 different proteins that were differentially expressed in the plasma of control diabetic patients (without retinopathy). Among these five proteins the expression of neuroglobin (NGB) protein varied significantly and may be a potential biomarker in diabetic retinopathy. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. Exploration of one-dimensional plasma current density profile for K-DEMO steady-state operation

    Energy Technology Data Exchange (ETDEWEB)

    Kang, J.S. [Seoul National University, Seoul 151-742 (Korea, Republic of); Jung, L. [National Fusion Research Institute, Daejeon (Korea, Republic of); Byun, C.-S.; Na, D.H.; Na, Y.-S. [Seoul National University, Seoul 151-742 (Korea, Republic of); Hwang, Y.S., E-mail: yhwang@snu.ac.kr [Seoul National University, Seoul 151-742 (Korea, Republic of)

    2016-11-01

    Highlights: • One-dimensional current density and its optimization for the K-DEMO are explored. • Plasma current density profile is calculated with an integrated simulation code. • The impact of self and external heating profiles is considered self-consistently. • Current density is identified as a reference profile by minimizing heating power. - Abstract: Concept study for Korean demonstration fusion reactor (K-DEMO) is in progress, and basic design parameters are proposed by targeting high magnetic field operation with ITER-sized machine. High magnetic field operation is a favorable approach to enlarge relative plasma performance without increasing normalized beta or plasma current. Exploration of one-dimensional current density profile and its optimization process for the K-DEMO steady-state operation are reported in this paper. Numerical analysis is conducted with an integrated plasma simulation code package incorporating a transport code with equilibrium and current drive modules. Operation regimes are addressed with zero-dimensional system analysis. One-dimensional plasma current density profile is calculated based on equilibrium, bootstrap current analysis, and thermal transport analysis. The impact of self and external heating profiles on those parameters is considered self-consistently, where thermal power balance and 100% non-inductive current drive are the main constraints during the whole exploration procedure. Current and pressure profiles are identified as a reference steady-state profile by minimizing the external heating power with desired fusion power.

  15. Analyzing the photonic band gaps in two-dimensional plasma photonic crystals with fractal Sierpinski gasket structure based on the Monte Carlo method

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Hai-Feng, E-mail: hanlor@163.com [College of Optoelectronic Engineering, Nanjing University of Posts and Telecommunications, Nanjing, 210023 ,China (China); Key Laboratory of Radar Imaging and Microwave Photonics (Nanjing Univ. Aeronaut. Astronaut.), Ministry of Education, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016 (China); Liu, Shao-Bin [Key Laboratory of Radar Imaging and Microwave Photonics (Nanjing Univ. Aeronaut. Astronaut.), Ministry of Education, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016 (China)

    2016-08-15

    In this paper, the properties of photonic band gaps (PBGs) in two types of two-dimensional plasma-dielectric photonic crystals (2D PPCs) under a transverse-magnetic (TM) wave are theoretically investigated by a modified plane wave expansion (PWE) method where Monte Carlo method is introduced. The proposed PWE method can be used to calculate the band structures of 2D PPCs which possess arbitrary-shaped filler and any lattice. The efficiency and convergence of the present method are discussed by a numerical example. The configuration of 2D PPCs is the square lattices with fractal Sierpinski gasket structure whose constituents are homogeneous and isotropic. The type-1 PPCs is filled with the dielectric cylinders in the plasma background, while its complementary structure is called type-2 PPCs, in which plasma cylinders behave as the fillers in the dielectric background. The calculated results reveal that the enough accuracy and good convergence can be obtained, if the number of random sampling points of Monte Carlo method is large enough. The band structures of two types of PPCs with different fractal orders of Sierpinski gasket structure also are theoretically computed for a comparison. It is demonstrate that the PBGs in higher frequency region are more easily produced in the type-1 PPCs rather than in the type-2 PPCs. Sierpinski gasket structure introduced in the 2D PPCs leads to a larger cutoff frequency, enhances and induces more PBGs in high frequency region. The effects of configurational parameters of two types of PPCs on the PBGs are also investigated in detail. The results show that the PBGs of the PPCs can be easily manipulated by tuning those parameters. The present type-1 PPCs are more suitable to design the tunable compacted devices.

  16. Two-dimensional particle simulation of negative ion extraction from a volume source

    International Nuclear Information System (INIS)

    Naitou, H.; Fukumasa, O.; Sakachou, K.; Mutou, K.

    1995-01-01

    Two-dimensional electrostatic particle simulation was done to study the extraction of negative ions from a volume plasma source. The simulation model is a rectangular system which consists of an extraction grid, a plasma grid, and a grounded wall. Full dynamics of electrons, ions, and negative ions are followed. Negative ions are extracted from the plasma region to the extraction grid through a slit in the plasma grid. For the lower value of extraction grid potential, the simulation results agree with the Child-Langumuir law, where the extracted negative ion current is proportional to the three-halves power of the potential of the extraction grid. For the higher value of extraction grid potential, the space charge effect of negative ions, which enter into the beamline at the top of the concavity of the positive ion boundary, reduces the negative ion current from the prediction of the Child-Langumuir law. ((orig.))

  17. Analysis of Maneuvering Targets with Complex Motions by Two-Dimensional Product Modified Lv's Distribution for Quadratic Frequency Modulation Signals.

    Science.gov (United States)

    Jing, Fulong; Jiao, Shuhong; Hou, Changbo; Si, Weijian; Wang, Yu

    2017-06-21

    For targets with complex motion, such as ships fluctuating with oceanic waves and high maneuvering airplanes, azimuth echo signals can be modeled as multicomponent quadratic frequency modulation (QFM) signals after migration compensation and phase adjustment. For the QFM signal model, the chirp rate (CR) and the quadratic chirp rate (QCR) are two important physical quantities, which need to be estimated. For multicomponent QFM signals, the cross terms create a challenge for detection, which needs to be addressed. In this paper, by employing a novel multi-scale parametric symmetric self-correlation function (PSSF) and modified scaled Fourier transform (mSFT), an effective parameter estimation algorithm is proposed-referred to as the Two-Dimensional product modified Lv's distribution (2D-PMLVD)-for QFM signals. The 2D-PMLVD is simple and can be easily implemented by using fast Fourier transform (FFT) and complex multiplication. These measures are analyzed in the paper, including the principle, the cross term, anti-noise performance, and computational complexity. Compared to the other three representative methods, the 2D-PMLVD can achieve better anti-noise performance. The 2D-PMLVD, which is free of searching and has no identifiability problems, is more suitable for multicomponent situations. Through several simulations and analyses, the effectiveness of the proposed estimation algorithm is verified.

  18. Experiment and simulation on one-dimensional plasma photonic crystals

    International Nuclear Information System (INIS)

    Zhang, Lin; Ouyang, Ji-Ting

    2014-01-01

    The transmission characteristics of microwaves passing through one-dimensional plasma photonic crystals (PPCs) have been investigated by experiment and simulation. The PPCs were formed by a series of discharge tubes filled with argon at 5 Torr that the plasma density in tubes can be varied by adjusting the discharge current. The transmittance of X-band microwaves through the crystal structure was measured under different discharge currents and geometrical parameters. The finite-different time-domain method was employed to analyze the detailed properties of the microwaves propagation. The results show that there exist bandgaps when the plasma is turned on. The properties of bandgaps depend on the plasma density and the geometrical parameters of the PPCs structure. The PPCs can perform as dynamical band-stop filter to control the transmission of microwaves within a wide frequency range

  19. Three-dimensional modelling of a dc non-transferred arc plasma torch

    International Nuclear Information System (INIS)

    Li Heping; Chen Xi

    2001-01-01

    Three-dimensional (3D) modelling results are presented concerning a direct current (dc) non-transferred arc plasma torch with axisymmetrical geometrical configuration and axisymmetrical boundary conditions. It is shown that the arc is locally attached at the anode surface of the plasma torch, and the heat transfer and plasma flow within the torch are of 3D features. The predicted arc root location at the anode surface and arc voltage of the torch are very consistent with corresponding experimental results. (author)

  20. Plasma Arc Cutting Dimensional Accuracy Optimization employing the Parameter Design approach

    Directory of Open Access Journals (Sweden)

    Kechagias John

    2017-01-01

    Full Text Available Plasma Arc Cutting (PAC is a thermal manufacturing process used for metal plates cutting. This work experimentally investigates the influence of process parameters onto the dimensional accuracy performance of the plasma arc cutting process. The cutting parameters studied were cutting speed (mm/min, torch standoff distance (mm, and arc voltage (volts. Linear dimensions of a rectangular workpiece were measured after PAC cutting following the full factorial design experimental approach. For each one of the three process parameters, three parameter levels were used. Analysis of means (ANOM and analysis of variances (ANOVA were performed in order for the effect of each parameter on the leaner dimensional accuracy to be assessed.

  1. Complex ray analysis for plasmas

    International Nuclear Information System (INIS)

    Connor, K.A.

    1980-01-01

    An extension of ray tracing techniques is considered for a variety of cases in which the dispersion relation of the plasma medium is complex. The ray trajectories are permitted to begin and/or at least travel through complex space-time; the wave propagation process so characterized becomes significant only where the rays intersect real space-time. It is found that rules and guidelines can be established for limited application of this idea

  2. Numerical investigation of three-dimensional single-species plasma equilibria on magnetic surfaces

    International Nuclear Information System (INIS)

    Lefrancois, Remi G.; Pedersen, Thomas Sunn; Boozer, Allen H.; Kremer, Jason P.

    2005-01-01

    Presented for the first time are numerical solutions to the three-dimensional nonlinear equilibrium equation for single-species plasmas confined on magnetic surfaces and surrounded by an equipotential boundary. The major-radial shift of such plasmas is found to be outward, qualitatively similar to the Shafranov shift of quasineutral plasmas confined on magnetic surfaces. However, this is the opposite of what occurs in the pure toroidal field equilibria of non-neutral plasmas (i.e., in the absence of magnetic surfaces). The effect of varying the number of Debye lengths in the plasma for the three-dimensional (3D) model is in agreement with previous 2D calculations: the potential varies significantly on magnetic surfaces for plasmas with few Debye lengths (a d ), and tends to be constant on surfaces when many Debye lengths are present (a > or approx. 10λ d ). For the case of a conducting boundary that does not conform to the outer magnetic surface, the plasma is shifted towards the conductor and the potential varies significantly on magnetic surfaces near the plasma edge. Debye shielding effects are clearly demonstrated when a nonuniform bias is applied to the boundary. Computed equilibrium profiles are presented for the Columbia Non-Neutral Torus [T. S. Pedersen, A. H. Boozer, J. P. Kermer, R. Lefrancois, F. Dahlgren, N. Pomphrey, W. Reiersen, and W. Dorland, Fusion Sci. Technol. 46, 200 (2004)], a stellarator designed to confine non-neutral plasmas

  3. Two dimensional radiated power diagnostics on Alcator C-Mod

    International Nuclear Information System (INIS)

    Reinke, M. L.; Hutchinson, I. H.

    2008-01-01

    The radiated power diagnostics for the Alcator C-Mod tokamak have been upgraded to measure two dimensional structure of the photon emissivity profile in order to investigate poloidal asymmetries in the core radiation. Commonly utilized unbiased absolute extreme ultraviolet (AXUV) diode arrays view the plasma along five different horizontal planes. The layout of the diagnostic set is shown and the results from calibrations and recent experiments are discussed. Data showing a significant, 30%-40%, inboard/outboard emissivity asymmetry during ELM-free H-mode are presented. The ability to use AXUV diode arrays to measure absolute radiated power is explored by comparing diode and resistive bolometer-based emissivity profiles for highly radiative L-mode plasmas seeded with argon. Emissivity profiles match in the core but disagree radially outward resulting in an underprediction of P rad of nearly 50% by the diodes compared to P rad determined using resistive bolometers.

  4. Two dimensional radiated power diagnostics on Alcator C-Moda)

    Science.gov (United States)

    Reinke, M. L.; Hutchinson, I. H.

    2008-10-01

    The radiated power diagnostics for the Alcator C-Mod tokamak have been upgraded to measure two dimensional structure of the photon emissivity profile in order to investigate poloidal asymmetries in the core radiation. Commonly utilized unbiased absolute extreme ultraviolet (AXUV) diode arrays view the plasma along five different horizontal planes. The layout of the diagnostic set is shown and the results from calibrations and recent experiments are discussed. Data showing a significant, 30%-40%, inboard/outboard emissivity asymmetry during ELM-free H-mode are presented. The ability to use AXUV diode arrays to measure absolute radiated power is explored by comparing diode and resistive bolometer-based emissivity profiles for highly radiative L-mode plasmas seeded with argon. Emissivity profiles match in the core but disagree radially outward resulting in an underprediction of Prad of nearly 50% by the diodes compared to Prad determined using resistive bolometers.

  5. Two-dimensional magnetohydrodynamic equilibria with flow and studies of equilibria fluctuations

    International Nuclear Information System (INIS)

    Agim, Y.Z.

    1989-08-01

    A set of reduced ideal MHD equations is derived to investigate equilibria of plasmas with mass flow in general two-dimensional geometry. These equations provide a means of investigating the effects of flow on self-consistent equilibria in a number of new two-dimensional configurations such as helically symmetric configurations with helical axis, which are relevant to stellarators, as well as axisymmetric configurations. It is found that as in the axisymmetric case, general two-dimensional flow equilibria are governed by a second-order quasi-linear partial differential equation for a magnetic flux function, which is coupled to a Bernoulli-type equation for the density. The equation for the magnetic flux function becomes hyperbolic at certain critical flow speeds which follow from its characteristic equation. When the equation is hyperbolic, shock phenomena may exist. As a particular example, unidirectional flow along the lines of symmetry is considered. In this case, the equation mentioned above is always elliptic. An exact solution for the case of helically symmetric unidirectional flow is found and studied to determine flow effects on the magnetic topology. In second part of this thesis, magnetic fluctuations due to the thermally excited MHD waves are investigated using fluid and kinetic models to describe stable, uniform, compressible plasma in the range above the drift wave frequency and below the ion cyclotron frequency. It is shown that the fluid model with resistivity yields spectral densities which are roughly Lorentzian, exhibit equipartition with no apparent cutoff in wavenumber space and a Bohm-type diffusion coefficient. Under certain conditions, the ensuing transport may be comparable to classical values. For a phenomenological cutoff imposed on the spectrum, the typical fluctuating-to-equilibrium magnetic field ratio is found to be of the order of 10 -10

  6. Two-dimensional full-wave code for reflectometry simulations in TJ-II

    International Nuclear Information System (INIS)

    Blanco, E.; Heuraux, S.; Estrada, T.; Sanchez, J.; Cupido, L.

    2004-01-01

    A two-dimensional full-wave code in the extraordinary mode has been developed to simulate reflectometry in TJ-II. The code allows us to study the measurement capabilities of the future correlation reflectometer that is being installed in TJ-II. The code uses the finite-difference-time-domain technique to solve Maxwell's equations in the presence of density fluctuations. Boundary conditions are implemented by a perfectly matched layer to simulate free propagation. To assure the stability of the code, the current equations are solved by a fourth-order Runge-Kutta method. Density fluctuation parameters such as fluctuation level, wave numbers, and correlation lengths are extrapolated from those measured at the plasma edge using Langmuir probes. In addition, realistic plasma shape, density profile, magnetic configuration, and experimental setup of TJ-II are included to determine the plasma regimes in which accurate information may be obtained

  7. Turbulent equipartitions in two dimensional drift convection

    International Nuclear Information System (INIS)

    Isichenko, M.B.; Yankov, V.V.

    1995-01-01

    Unlike the thermodynamic equipartition of energy in conservative systems, turbulent equipartitions (TEP) describe strongly non-equilibrium systems such as turbulent plasmas. In turbulent systems, energy is no longer a good invariant, but one can utilize the conservation of other quantities, such as adiabatic invariants, frozen-in magnetic flux, entropy, or combination thereof, in order to derive new, turbulent quasi-equilibria. These TEP equilibria assume various forms, but in general they sustain spatially inhomogeneous distributions of the usual thermodynamic quantities such as density or temperature. This mechanism explains the effects of particle and energy pinch in tokamaks. The analysis of the relaxed states caused by turbulent mixing is based on the existence of Lagrangian invariants (quantities constant along fluid-particle or other orbits). A turbulent equipartition corresponds to the spatially uniform distribution of relevant Lagrangian invariants. The existence of such turbulent equilibria is demonstrated in the simple model of two dimensional electrostatically turbulent plasma in an inhomogeneous magnetic field. The turbulence is prescribed, and the turbulent transport is assumed to be much stronger than the classical collisional transport. The simplicity of the model makes it possible to derive the equations describing the relaxation to the TEP state in several limits

  8. Three-dimensional flow in electromagnetically driven shallow two-layer fluids

    NARCIS (Netherlands)

    Akkermans, R.A.D.; Kamp, L.P.J.; Clercx, H.J.H.; van Heijst, G.J.F.

    2010-01-01

    Recent experiments on a freely evolving dipolar vortex in a homogeneous shallow fluid layer have clearly shown the existence and evolution of complex three-dimensional 3D flow structures. The present contribution focuses on the 3D structures of a dipolar vortex evolving in a stable shallow two-layer

  9. Impact of the plasma response in three-dimensional edge plasma transport modelling for RMP ELM control scenarios at ITER

    Science.gov (United States)

    Schmitz, Oliver

    2014-10-01

    The constrains used in magneto-hydrodynamic (MHD) modeling of the plasma response to external resonant magnetic perturbation (RMP) fields have a profound impact on the three-dimensional (3-D) shape of the plasma boundary induced by RMP fields. In this contribution, the consequences of the plasma response on the actual 3D boundary structure and transport during RMP application at ITER are investigated. The 3D fluid plasma and kinetic neutral transport code EMC3-Eirene is used for edge transport modeling. Plasma response modeling is conducted with the M3D-C1 code using a single fluid, non-linear and a two fluid, linear MHD constrain. These approaches are compared to results with an ideal MHD like plasma response. A 3D plasma boundary is formed for all cases consisting of magnetic finger structures at the X-point intersecting the divertor surface in a helical footprint pattern. The width of the helical footprint pattern is largely reduced compared to vacuum magnetic fields when using the ideal MHD like screening model. This yields increasing peak heat fluxes in contrast to a beneficial heat flux spreading seen with vacuum fields. The particle pump out as well as loss of thermal energy is reduced by a factor of two compared to vacuum fields. In contrast, the impact of the plasma response obtained from both MHD constrains in M3D-C1 is nearly negligible at the plasma boundary and only a small modification of the magnetic footprint topology is detected. Accordingly, heat and particle fluxes on the target plates as well as the edge transport characteristics are comparable to the vacuum solution. This span of modeling results with different plasma response models highlights the importance of thoroughly validating both, plasma response and 3D edge transport models for a robust extrapolation towards ITER. Supported by ITER Grant IO/CT/11/4300000497 and F4E Grant GRT-055 (PMS-PE) and by Start-Up Funds of the University of Wisconsin - Madison.

  10. One-dimensional Co(II)/Ni(II) complexes of 2-hydroxyisophthalate: Structures and magnetic properties

    International Nuclear Information System (INIS)

    Wang, Kai; Zou, Hua-Hong; Chen, Zi-Lu; Zhang, Zhong; Sun, Wei-Yin; Liang, Fu-Pei

    2015-01-01

    The solvothermal reactions of 2-hydroxyisophthalic acid (H 3 ipO) with M(NO 3 ) 2 ∙6H 2 O (M=Co, Ni) afforded two complexes [Co 2 (HipO) 2 (Py) 2 (H 2 O) 2 ] (1) and [Ni(HipO)(Py)H 2 O] (2) (Py=pyridine). They exhibit similar zig-zag chain structures with the adjacent two metal centers connected by a anti-syn bridging carboxylate group from the HipO 2− ligand. The magnetic measurements reveal the dominant antiferromagnetic interactions and spin-canting in 1 while ferromagnetic interactions in 2. Both of them exhibit magnetocaloric effect (MCE) with the resulting entropy changes (−ΔS m ) of 12.51 J kg −1 K −1 when ΔH=50 kOe at 3 K for 1 and 11.01 J kg −1 K −1 when ΔH=50 kOe at 3 K for 2, representing the rare examples of one-dimensional complexes with MCE. - Graphical abstract: Synopsis: Two Co(II)/Ni(II) complexes with zig-zag chain structures have been reported. 1-Co shows cant-antiferromagnetism while 2-Ni shows ferromagnetism. Magnetocaloric effect is also found in both of them. - Highlights: • Two one-dimensional Co(II)/Ni(II) complexes were solvothermally synthesized. • The Co-complex exhibits canted antiferromagnetism. • The Ni-complex exhibits ferromagnetism. • Both of the complexes display magnetocaloric effect

  11. Acoustic rotation modes in complex plasmas

    International Nuclear Information System (INIS)

    Bai Dongxue; Wang Zhengxiong; Wang Xiaogang

    2004-01-01

    Acoustic rotation modes in complex plasmas are investigated in a cylindrical system with an axial symmetry. The linear mode solution is derived. The mode in an infinite area is reduced to a classical dust acoustic wave in the region away from the centre. When the dusty plasma is confined in a finite region, the breathing and rotating-void behaviour are observed. Vivid structures of different mode number solutions are illustrated

  12. Complexity of hierarchically and 1-dimensional periodically specified problems

    Energy Technology Data Exchange (ETDEWEB)

    Marathe, M.V.; Hunt, H.B. III; Stearns, R.E.; Radhakrishnan, V.

    1995-08-23

    We study the complexity of various combinatorial and satisfiability problems when instances are specified using one of the following specifications: (1) the 1-dimensional finite periodic narrow specifications of Wanke and Ford et al. (2) the 1-dimensional finite periodic narrow specifications with explicit boundary conditions of Gale (3) the 2-way infinite1-dimensional narrow periodic specifications of Orlin et al. and (4) the hierarchical specifications of Lengauer et al. we obtain three general types of results. First, we prove that there is a polynomial time algorithm that given a 1-FPN- or 1-FPN(BC)specification of a graph (or a C N F formula) constructs a level-restricted L-specification of an isomorphic graph (or formula). This theorem along with the hardness results proved here provides alternative and unified proofs of many hardness results proved in the past either by Lengauer and Wagner or by Orlin. Second, we study the complexity of generalized CNF satisfiability problems of Schaefer. Assuming P {ne} PSPACE, we characterize completely the polynomial time solvability of these problems, when instances are specified as in (1), (2),(3) or (4). As applications of our first two types of results, we obtain a number of new PSPACE-hardness and polynomial time algorithms for problems specified as in (1), (2), (3) or(4). Many of our results also hold for O(log N) bandwidth bounded planar instances.

  13. Separation of complex fringe patterns using two-dimensional continuous wavelet transform.

    Science.gov (United States)

    Pokorski, Krzysztof; Patorski, Krzysztof

    2012-12-10

    A method for processing fringe patterns containing additively superimposed multiple fringe sets is presented. It enables to analyze different fringe families present in a single image separately. The proposed method is based on a two-dimensional continuous wavelet transform. A robust ridge extraction algorithm for a single fringe set extraction is presented. The method is fully automatic and requires no user interference. Spectral separation of fringe families is not required. Simulations are presented to verify performance and advantage of the proposed method over the Fourier transform based technique. Method validity has been confirmed using experimental images.

  14. The role of plasma proteins in formation of obstructive protamine complexes

    International Nuclear Information System (INIS)

    De Paulis, R.; Mohammad, S.F.; Chiariello, L.; Morea, M.; Olsen, D.B.

    1991-01-01

    Formation of complexes between heparin and protamine (in saline), or heparin, plasma proteins, and protamine (in plasma) was assessed by measurements of light transmission through different test solutions. To examine the formation of these complexes, 125I-labeled protamine was used. Addition of 125I-protamine to plasma or blood resulted in the sedimentation of 125I-protamine in the form of insoluble complexes. This complex formation was not affected by the presence of heparin, suggesting that protamine-plasma protein interaction may be primarily responsible for precipitation of 125I-protamine. To assess the capability of these complexes to obstruct the pulmonary circulation, an in vitro experimental model was developed. Citrated serum, plasma, blood, or saline were allowed to flow through a glass bead column with the help of a peristaltic pump. A pressure transducer positioned before the column allowed pressure measurements at a constant flow rate during the experiment. Mixing of protamine with plasma or blood prior to their passage through the glass bead column resulted in a significant increase in pressure suggesting that the column was being clogged with insoluble complexes. The increase in pressure occurred both in the presence and absence of heparin in plasma or blood. Under identical experimental conditions, the increase in pressure was insignificant when protamine was added to saline or serum regardless of whether heparin was present or absent. This was further confirmed by the use of 125I-protamine. These observations suggest that protamine forms insoluble complexes with certain plasma proteins. Based on these observations, it is hypothesized that following intravenous administration, protamine immediately forms complexes in circulating blood

  15. Two-Dimensional Spectroscopy Is Being Used to Address Core Scientific Questions in Biology and Materials Science.

    Science.gov (United States)

    Petti, Megan K; Lomont, Justin P; Maj, Michał; Zanni, Martin T

    2018-02-15

    Two-dimensional spectroscopy is a powerful tool for extracting structural and dynamic information from a wide range of chemical systems. We provide a brief overview of the ways in which two-dimensional visible and infrared spectroscopies are being applied to elucidate fundamental details of important processes in biological and materials science. The topics covered include amyloid proteins, photosynthetic complexes, ion channels, photovoltaics, batteries, as well as a variety of promising new methods in two-dimensional spectroscopy.

  16. A one-dimensional Q-machine model taking into account charge-exchange collisions

    International Nuclear Information System (INIS)

    Maier, H.; Kuhn, S.

    1992-01-01

    The Q-machine is a nontrivial bounded plasma system which is excellently suited not only for fundamental plasma physics investigations but also for the development and testing of new theoretical methods for modeling such systems. However, although Q-machines have now been around for over thirty years, it appears that there exist no comprehensive theoretical models taking into account their considerable geometrical and physical complexity with a reasonable degree of self-consistency. In the present context we are concerned with the low-density, single-emitter Q-machine, for which the most widely used model is probably the (one-dimensional) ''collisionless plane-diode model'', which has originally been developed for thermionic diodes. Although the validity of this model is restricted to certain ''axial'' phenomena, we consider it a suitable starting point for extensions of various kinds. While a generalization to two-dimensional geometry (with still collisionless plasma) is being reported elsewhere, the present work represents a first extension to collisional plasma (with still one-dimensional geometry). (author) 12 refs., 2 figs

  17. Investigation of organometallic reaction mechanisms with one and two dimensional vibrational spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Cahoon, James Francis [Univ. of California, Berkeley, CA (United States)

    2008-12-01

    One and two dimensional time-resolved vibrational spectroscopy has been used to investigate the elementary reactions of several prototypical organometallic complexes in room temperature solution. The electron transfer and ligand substitution reactions of photogenerated 17-electron organometallic radicals CpW(CO)3 and CpFe(CO)2 have been examined with one dimensional spectroscopy on the picosecond through microsecond time-scales, revealing the importance of caging effects and odd-electron intermediates in these reactions. Similarly, an investigation of the photophysics of the simple Fischer carbene complex Cr(CO)5[CMe(OMe)] showed that this class of molecule undergoes an unusual molecular rearrangement on the picosecond time-scale, briefly forming a metal-ketene complex. Although time-resolved spectroscopy has long been used for these types of photoinitiated reactions, the advent of two dimensional vibrational spectroscopy (2D-IR) opens the possibility to examine the ultrafast dynamics of molecules under thermal equilibrium conditions. Using this method, the picosecond fluxional rearrangements of the model metal carbonyl Fe(CO)5 have been examined, revealing the mechanism, time-scale, and transition state of the fluxional reaction. The success of this experiment demonstrates that 2D-IR is a powerful technique to examine the thermally-driven, ultrafast rearrangements of organometallic molecules in solution.

  18. Comparative analysis of peak-detection techniques for comprehensive two-dimensional chromatography.

    Science.gov (United States)

    Latha, Indu; Reichenbach, Stephen E; Tao, Qingping

    2011-09-23

    Comprehensive two-dimensional gas chromatography (GC×GC) is a powerful technology for separating complex samples. The typical goal of GC×GC peak detection is to aggregate data points of analyte peaks based on their retention times and intensities. Two techniques commonly used for two-dimensional peak detection are the two-step algorithm and the watershed algorithm. A recent study [4] compared the performance of the two-step and watershed algorithms for GC×GC data with retention-time shifts in the second-column separations. In that analysis, the peak retention-time shifts were corrected while applying the two-step algorithm but the watershed algorithm was applied without shift correction. The results indicated that the watershed algorithm has a higher probability of erroneously splitting a single two-dimensional peak than the two-step approach. This paper reconsiders the analysis by comparing peak-detection performance for resolved peaks after correcting retention-time shifts for both the two-step and watershed algorithms. Simulations with wide-ranging conditions indicate that when shift correction is employed with both algorithms, the watershed algorithm detects resolved peaks with greater accuracy than the two-step method. Copyright © 2011 Elsevier B.V. All rights reserved.

  19. On the two-dimensional Saigo-Maeda fractional calculus asociated with two-dimensional Aleph TRANSFORM

    Directory of Open Access Journals (Sweden)

    Dinesh Kumar

    2013-11-01

    Full Text Available This paper deals with the study of two-dimensional Saigo-Maeda operators of Weyl type associated with Aleph function defined in this paper. Two theorems on these defined operators are established. Some interesting results associated with the H-functions and generalized Mittag-Leffler functions are deduced from the derived results. One dimensional analog of the derived results is also obtained.

  20. A microprocessor based on a two-dimensional semiconductor

    Science.gov (United States)

    Wachter, Stefan; Polyushkin, Dmitry K.; Bethge, Ole; Mueller, Thomas

    2017-04-01

    The advent of microcomputers in the 1970s has dramatically changed our society. Since then, microprocessors have been made almost exclusively from silicon, but the ever-increasing demand for higher integration density and speed, lower power consumption and better integrability with everyday goods has prompted the search for alternatives. Germanium and III-V compound semiconductors are being considered promising candidates for future high-performance processor generations and chips based on thin-film plastic technology or carbon nanotubes could allow for embedding electronic intelligence into arbitrary objects for the Internet-of-Things. Here, we present a 1-bit implementation of a microprocessor using a two-dimensional semiconductor--molybdenum disulfide. The device can execute user-defined programs stored in an external memory, perform logical operations and communicate with its periphery. Our 1-bit design is readily scalable to multi-bit data. The device consists of 115 transistors and constitutes the most complex circuitry so far made from a two-dimensional material.

  1. Two-fluid and parallel compressibility effects in tokamak plasmas

    International Nuclear Information System (INIS)

    Sugiyama, L.E.; Park, W.

    1998-01-01

    The MHD, or single fluid, model for a plasma has long been known to provide a surprisingly good description of much of the observed nonlinear dynamics of confined plasmas, considering its simple nature compared to the complexity of the real system. On the other hand, some of the supposed agreement arises from the lack of the detailed measurements that are needed to distinguish MHD from more sophisticated models that incorporate slower time scale processes. At present, a number of factors combine to make models beyond MHD of practical interest. Computational considerations still favor fluid rather than particle models for description of the full plasma, and suggest an approach that starts from a set of fluid-like equations that extends MHD to slower time scales and more accurate parallel dynamics. This paper summarizes a set of two-fluid equations for toroidal (tokamak) geometry that has been developed and tested as the MH3D-T code [1] and some results from the model. The electrons and ions are described as separate fluids. The code and its original MHD version, MH3D [2], are the first numerical, initial value models in toroidal geometry that include the full 3D (fluid) compressibility and electromagnetic effects. Previous nonlinear MHD codes for toroidal geometry have, in practice, neglected the plasma density evolution, on the grounds that MHD plasmas are only weakly compressible and that the background density variation is weaker than the temperature variation. Analytically, the common use of toroidal plasma models based on aspect ratio expansion, such as reduced MHD, has reinforced this impression, since this ordering reduces plasma compressibility effects. For two-fluid plasmas, the density evolution cannot be neglected in principle, since it provides the basic driving energy for the diamagnetic drifts of the electrons and ions perpendicular to the magnetic field. It also strongly influences the parallel dynamics, in combination with the parallel thermal

  2. Self-organization and oscillation of negatively charged dust particles in a 2-dimensional dusty plasma

    Energy Technology Data Exchange (ETDEWEB)

    Song, Y.L. [College of Science, China Agricultural University, Beijing 100083 (China); Huang, F., E-mail: huangfeng@cau.edu.cn [College of Science, China Agricultural University, Beijing 100083 (China); Chen, Z.Y., E-mail: chenzy@mail.buct.edu.cn [Department of Physics, Beijing University of Chemical Technology, Beijing 100029 (China); State Key Laboratory of Laser Propulsion & Application, Beijing 101416 (China); Liu, Y.H. [School of Physics and Optoelectronic Engineering, Ludong University, Yantai 264025 (China); Yu, M.Y. [Institute for Fusion Theory and Simulation, Zhejiang University, Hangzhou 310027 (China); Institute for Theoretical Physics I, Ruhr University, D-44801 Bochum (Germany)

    2016-02-22

    Negatively charged dust particles immersed in 2-dimensional dusty plasma system are investigated by molecular dynamics simulations. The effects of the confinement potential and attraction interaction potential on dust particle self-organization are studied in detail and two typical dust particle distributions are obtained when the system reaches equilibrium. The average radial velocity (ARV), average radial force (ARF) and radial mean square displacement are employed to analyze the dust particles' dynamics. Both ARVs and ARFs exhibit oscillation behaviors when the simulation system reaches equilibrium state. The relationships between the oscillation and confinement potential and attraction potential are studied in this paper. The simulation results are qualitatively similar to experimental results. - Highlights: • Self-organization and oscillation of a 2-dimensional dusty plasma is investigated. • Effect of the confinement potential on dust self-organization and oscillation is given. • Effect of the attraction potential on dust self-organization and oscillation is studied.

  3. Self-organization and oscillation of negatively charged dust particles in a 2-dimensional dusty plasma

    International Nuclear Information System (INIS)

    Song, Y.L.; Huang, F.; Chen, Z.Y.; Liu, Y.H.; Yu, M.Y.

    2016-01-01

    Negatively charged dust particles immersed in 2-dimensional dusty plasma system are investigated by molecular dynamics simulations. The effects of the confinement potential and attraction interaction potential on dust particle self-organization are studied in detail and two typical dust particle distributions are obtained when the system reaches equilibrium. The average radial velocity (ARV), average radial force (ARF) and radial mean square displacement are employed to analyze the dust particles' dynamics. Both ARVs and ARFs exhibit oscillation behaviors when the simulation system reaches equilibrium state. The relationships between the oscillation and confinement potential and attraction potential are studied in this paper. The simulation results are qualitatively similar to experimental results. - Highlights: • Self-organization and oscillation of a 2-dimensional dusty plasma is investigated. • Effect of the confinement potential on dust self-organization and oscillation is given. • Effect of the attraction potential on dust self-organization and oscillation is studied.

  4. Entropic Barriers for Two-Dimensional Quantum Memories

    Science.gov (United States)

    Brown, Benjamin J.; Al-Shimary, Abbas; Pachos, Jiannis K.

    2014-03-01

    Comprehensive no-go theorems show that information encoded over local two-dimensional topologically ordered systems cannot support macroscopic energy barriers, and hence will not maintain stable quantum information at finite temperatures for macroscopic time scales. However, it is still well motivated to study low-dimensional quantum memories due to their experimental amenability. Here we introduce a grid of defect lines to Kitaev's quantum double model where different anyonic excitations carry different masses. This setting produces a complex energy landscape which entropically suppresses the diffusion of excitations that cause logical errors. We show numerically that entropically suppressed errors give rise to superexponential inverse temperature scaling and polynomial system size scaling for small system sizes over a low-temperature regime. Curiously, these entropic effects are not present below a certain low temperature. We show that we can vary the system to modify this bound and potentially extend the described effects to zero temperature.

  5. The three-dimensional positioning system at the VINETA.II experiment—a multipurpose tool for in situ plasma diagnostics

    Science.gov (United States)

    Shesterikov, I.; Milojevic, D.; von Stechow, A.; Rahbarnia, K.; Grulke, O.; Klinger, T.

    2017-08-01

    The manipulator systems installed at the VINETA.II magnetic reconnection experiment are essential elements for experimental investigation of local plasma parameters. A novel three-dimensional (3D) probe manipulator has been designed, implemented and successfully operated at VINETA.II. This work presents its design and performance for three-dimensional measurements of VINETA.II plasmas. Its design consists of three vertically stacked independent and mutually perpendicular linear motion stages which allow flexible positioning of diagnostic tools such as electrical and magnetic probes or optical diagnostics within the vacuum vessel. Its design features include a wide spatial coverage, sub-millimeter positioning accuracy and the capability to operate in a harsh environment under the influence of microwaves, radio-frequency waves and direct contact with plasma. Manipulator performance is assessed by measuring a volumetric distribution of plasma parameters by a B-dot probe. A typical discharge of the magnetic reconnection setup in VINETA.II with a pulse time of τ=600 μs is chosen for this purpose. The azimuthal magnetic field distribution measured with the 3D manipulator agrees favorably with measurements obtained by the two-dimensional (2D) manipulator, used at VINETA.II as a standard reference diagnostic tool, thereby demonstrating its reliability and performance. A programmable stepper motor controller (TMCM-1110) that is operated remotely by a PC drives all possible features of the manipulator system.

  6. Plasma Arc Cutting Dimensional Accuracy Optimization employing the Parameter Design approach

    OpenAIRE

    Kechagias John; Petousis Markos; Vidakis Nectarios; Mastorakis Nikos

    2017-01-01

    Plasma Arc Cutting (PAC) is a thermal manufacturing process used for metal plates cutting. This work experimentally investigates the influence of process parameters onto the dimensional accuracy performance of the plasma arc cutting process. The cutting parameters studied were cutting speed (mm/min), torch standoff distance (mm), and arc voltage (volts). Linear dimensions of a rectangular workpiece were measured after PAC cutting following the full factorial design experimental approach. For ...

  7. Numerical studies of unsteady coherent structures and transport in two-dimensional flows

    Energy Technology Data Exchange (ETDEWEB)

    Hesthaven, J.S.

    1995-08-01

    The dynamics of unsteady two-dimensional coherent structures in various physical systems is studied through direct numerical solution of the dynamical equations using spectral methods. The relation between the Eulerian and the Lagrangian auto-correlation functions in two-dimensional homogeneous, isotropic turbulence is studied. A simple analytic expression for the Eulerian and Lagrangian auto-correlation function for the fluctuating velocity field is derived solely on the basis of the one-dimensional power spectrum. The long-time evolution of monopolar and dipolar vortices in anisotropic systems relevant for geophysics and plasma physics is studied by direct numerical solution. Transport properties and spatial reorganization of vortical structures are found to depend strongly on the initial conditions. Special attention is given to the dynamics of strong monopoles and the development of unsteady tripolar structures. The development of coherent structures in fluid flows, incompressible as well as compressible, is studied by novel numerical schemes. The emphasis is on the development of spectral methods sufficiently advanced as to allow for detailed and accurate studies of the self-organizing processes. (au) 1 ill., 94 refs.

  8. Two-dimensional nuclear magnetic resonance spectroscopy

    International Nuclear Information System (INIS)

    Bax, A.; Lerner, L.

    1986-01-01

    Great spectral simplification can be obtained by spreading the conventional one-dimensional nuclear magnetic resonance (NMR) spectrum in two independent frequency dimensions. This so-called two-dimensional NMR spectroscopy removes spectral overlap, facilitates spectral assignment, and provides a wealth of additional information. For example, conformational information related to interproton distances is available from resonance intensities in certain types of two-dimensional experiments. Another method generates 1 H NMR spectra of a preselected fragment of the molecule, suppressing resonances from other regions and greatly simplifying spectral appearance. Two-dimensional NMR spectroscopy can also be applied to the study of 13 C and 15 N, not only providing valuable connectivity information but also improving sensitivity of 13 C and 15 N detection by up to two orders of magnitude. 45 references, 10 figures

  9. Two-dimensional analysis for a scrapeoff and divertor regions with an MHD model

    International Nuclear Information System (INIS)

    Ueda, Noriaki; Kasai, Masao; Hitoki, Shigehisa

    1987-08-01

    With a two-dimensional time dependent fluid code for transport processes in the edge plasma in a tokamak, coupled with Monte-Carlo method for neutral gas behavior, preliminary numerical study has been carried out for the FER divertor. Design base data such as energy flux, particle flux and so on which are essentially important to make an divertor design reliable have been obtained. (author)

  10. Simulating signatures of two-dimensional electronic spectra of the Fenna-Matthews-Olson complex: By using a numerical path integral

    International Nuclear Information System (INIS)

    Liang, Xian-Ting

    2014-01-01

    A framework for simulating electronic spectra from photon-echo experiments is constructed by using a numerical path integral technique. This method is non-Markovian and nonperturbative and, more importantly, is not limited by a fixed form of the spectral density functions of the environment. Next, a two-dimensional (2D) third-order electronic spectrum of a dimer system is simulated. The spectrum is in agreement with the experimental and theoretical results previously reported [for example, M. Khalil, N. Demirdöven, and A. Tokmakoff, Phys. Rev. Lett. 90, 047401 (2003)]. Finally, a 2D third-order electronic spectrum of the Fenna-Matthews-Olson (FMO) complex is simulated by using the Debye, Ohmic, and Adolphs and Renger spectral density functions. It is shown that this method can clearly produce the spectral signatures of the FMO complex by using only the Adolphs and Renger spectral density function. Plots of the evolution of the diagonal and cross-peaks show that they are oscillating with the population time

  11. Plasma Dispersion Functions for Complex Frequencies

    International Nuclear Information System (INIS)

    Pavlov, S. S.; Castejon, F.

    2005-01-01

    Plasma dispersion functions for complex wave propagation frequency in the weak relativistic regime for arbitrary longitudinal refractive index are estimated and presented in this work. These functions, that are know as Shkarofsky functions in the case of real frequency, are estimated using a new method that avoids the singularities that appear in previous calculations shown in the preceding literature. These results can be used to obtain the properties of plasma instabilities in the weakly relativistic regime. (Author) 14 refs

  12. Numerical simulation of complex multi-dimensional two-phase flows in nuclear power plant coolant circuits by means of the best-estimate thermal-hydraulic code BAGIRA

    International Nuclear Information System (INIS)

    Kalinichenko, S.D.; Kroshilin, A.E.; Kroshilin, V.E.; Smirnov, A.V.

    2009-01-01

    Recent results are exposed, obtained by applying the best-estimate thermal hydraulic code BAGIRA for three-dimensional modeling complex two-phase flow dynamics inside the vessel of the horizontal steam generator PGV-1000 used in reactor units with VVER-1000. Spatial volumetric void fraction and velocity distributions are calculated and compared with available experimental data. (author)

  13. On some classes of two-dimensional local models in discrete two-dimensional monatomic FPU lattice with cubic and quartic potential

    International Nuclear Information System (INIS)

    Quan, Xu; Qiang, Tian

    2009-01-01

    This paper discusses the two-dimensional discrete monatomic Fermi–Pasta–Ulam lattice, by using the method of multiple-scale and the quasi-discreteness approach. By taking into account the interaction between the atoms in the lattice and their nearest neighbours, it obtains some classes of two-dimensional local models as follows: two-dimensional bright and dark discrete soliton trains, two-dimensional bright and dark line discrete breathers, and two-dimensional bright and dark discrete breather. (condensed matter: structure, thermal and mechanical properties)

  14. Two-dimensional electronic spectroscopy with birefringent wedges

    Energy Technology Data Exchange (ETDEWEB)

    Réhault, Julien; Maiuri, Margherita; Oriana, Aurelio; Cerullo, Giulio [IFN-CNR, Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano (Italy)

    2014-12-15

    We present a simple experimental setup for performing two-dimensional (2D) electronic spectroscopy in the partially collinear pump-probe geometry. The setup uses a sequence of birefringent wedges to create and delay a pair of phase-locked, collinear pump pulses, with extremely high phase stability and reproducibility. Continuous delay scanning is possible without any active stabilization or position tracking, and allows to record rapidly and easily 2D spectra. The setup works over a broad spectral range from the ultraviolet to the near-IR, it is compatible with few-optical-cycle pulses and can be easily reconfigured to two-colour operation. A simple method for scattering suppression is also introduced. As a proof of principle, we present degenerate and two-color 2D spectra of the light-harvesting complex 1 of purple bacteria.

  15. Small amplitude two dimensional electrostatic excitations in a magnetized dusty plasma with q-distributed electrons

    Science.gov (United States)

    Khan, Shahab Ullah; Adnan, Muhammad; Qamar, Anisa; Mahmood, Shahzad

    2016-07-01

    The propagation of linear and nonlinear electrostatic waves is investigated in magnetized dusty plasma with stationary negatively or positively charged dust, cold mobile ions and non-extensive electrons. Two normal modes are predicted in the linear regime, whose characteristics are investigated parametrically, focusing on the effect of electrons non-extensivity, dust charge polarity, concentration of dust and magnetic field strength. Using the reductive perturbation technique, a Zakharov-Kuznetsov (ZK) type equation is derived which governs the dynamics of small-amplitude solitary waves in magnetized dusty plasma. The properties of the solitary wave structures are analyzed numerically with the system parameters i.e. electrons non-extensivity, concentration of dust, polarity of dust and magnetic field strength. Following Allen and Rowlands (J. Plasma Phys. 53:63, 1995), we have shown that the pulse soliton solution of the ZK equation is unstable, and have analytically traced the dependence of the instability growth rate on the nonextensive parameter q for electrons, dust charge polarity and magnetic field strength. The results should be useful for understanding the nonlinear propagation of DIA solitary waves in laboratory and space plasmas.

  16. Two-dimensional models

    International Nuclear Information System (INIS)

    Schroer, Bert; Freie Universitaet, Berlin

    2005-02-01

    It is not possible to compactly review the overwhelming literature on two-dimensional models in a meaningful way without a specific viewpoint; I have therefore tacitly added to the above title the words 'as theoretical laboratories for general quantum field theory'. I dedicate this contribution to the memory of J. A. Swieca with whom I have shared the passion of exploring 2-dimensional models for almost one decade. A shortened version of this article is intended as a contribution to the project 'Encyclopedia of mathematical physics' and comments, suggestions and critical remarks are welcome. (author)

  17. Measurement of net electric charge and dipole moment of dust aggregates in a complex plasma.

    Science.gov (United States)

    Yousefi, Razieh; Davis, Allen B; Carmona-Reyes, Jorge; Matthews, Lorin S; Hyde, Truell W

    2014-09-01

    Understanding the agglomeration of dust particles in complex plasmas requires knowledge of basic properties such as the net electrostatic charge and dipole moment of the dust. In this study, dust aggregates are formed from gold-coated mono-disperse spherical melamine-formaldehyde monomers in a radiofrequency (rf) argon discharge plasma. The behavior of observed dust aggregates is analyzed both by studying the particle trajectories and by employing computer models examining three-dimensional structures of aggregates and their interactions and rotations as induced by torques arising from their dipole moments. These allow the basic characteristics of the dust aggregates, such as the electrostatic charge and dipole moment, as well as the external electric field, to be determined. It is shown that the experimental results support the predicted values from computer models for aggregates in these environments.

  18. Coupled two-dimensional edge-plasma and neutral gas modelling of the DIII-D scrape-off-layer

    International Nuclear Information System (INIS)

    Maingi, R.; Gilligan, J.; Hankins, O.; Rensink, M.; Owen, L.; Klepper, C.; Mioduszewski, P.

    1992-01-01

    This paper reports that in order to do consistent scrape-off-layer plasma and neutral transport calculations, the 2-D fluid code, B2 has been externally coupled to the neutral transport code, DEGAS, for Dlll-D. The coupling procedure is similar to recent simulations done for TFTR, Tore Supra, and ClT. An averaged source approach is utilized to allow convergence between the two codes. Initial comparison of plasma quantities between the coupled code set and the B2 code alone shows that a colder, denser plasma may exist at the divertor targets than predicted by the B2 code with its internal recycling model

  19. 3+1 dimensional envelop waves and its stability in magnetized dusty plasma

    International Nuclear Information System (INIS)

    Duan Wenshan

    2006-01-01

    It is well known that there are envelope solitary waves in unmagnetized dusty plasmas which are described by a nonlinear Schrodinger equation (NLSE). A three dimension nonlinear Schrodinger equation for small but finite amplitude dust acoustic waves is first obtained for magnetized dusty plasma in this paper. It suggest that in magnetized dusty plasmas the envelope solitary waves exist. The modulational instability for three dimensional NLSE is studied as well. The regions of stability and instability are well determined in this paper

  20. Cooperative particle motion in complex (dusty) plasmas

    Science.gov (United States)

    Zhdanov, Sergey; Morfill, Gregor

    2014-05-01

    Strongly coupled complex (dusty) plasmas give us a unique opportunity to go beyond the limits of continuous media and study various generic processes occurring in liquids or solids at the kinetic level. A particularly interesting and challenging topic is to study dynamic cooperativity at local and intermediate scales. As an important element of self-organization, cooperative particle motion is present in many physical, astrophysical and biological systems. As a rule, cooperative dynamics, bringing to life 'abnormal' effects like enhanced diffusion, self-dragging, or self-propelling of particles, hold aspects of 'strange' kinetics. The synergy effects are also important. Such kind of cooperative behavior was evidenced for string-like formations of colloidal rods, dynamics of mono- and di-vacancies in 2d colloidal crystals. Externally manipulated 'dust molecules' and self-assembled strings in driven 3d particle clusters were other noticeable examples. There is a certain advantage to experiment with complex plasmas merely because these systems are easy to manipulate in a controllable way. We report on the first direct observation of microparticle cooperative movements occurring under natural conditions in a 2d complex plasma.

  1. Hofstadter's butterfly in a two-dimensional lattice consisting of two sublattices

    International Nuclear Information System (INIS)

    Vugalter, G A; Pastukhov, A S

    2004-01-01

    Harper's equations for simple and complex two-dimensional lattices subject to a magnetic field have been derived in the tight-binding approximation. In our derivation we do not neglect the influence of the magnetic field on the electron eigenfunctions and eigenvalues in isolated atoms. Using a variational procedure for finding eigenfunctions and eigenvalues, we have self-consistently obtained Hofstadter's butterflies. Even for a simple square lattice Hofstadter's butterfly differs from the butterfly obtained in the case in which the influence of the magnetic field on the electron eigenvalues and eigenfunctions in isolated atoms is not taken into account

  2. A simple highly accurate field-line mapping technique for three-dimensional Monte Carlo modeling of plasma edge transport

    International Nuclear Information System (INIS)

    Feng, Y.; Sardei, F.; Kisslinger, J.

    2005-01-01

    The paper presents a new simple and accurate numerical field-line mapping technique providing a high-quality representation of field lines as required by a Monte Carlo modeling of plasma edge transport in the complex magnetic boundaries of three-dimensional (3D) toroidal fusion devices. Using a toroidal sequence of precomputed 3D finite flux-tube meshes, the method advances field lines through a simple bilinear, forward/backward symmetric interpolation at the interfaces between two adjacent flux tubes. It is a reversible field-line mapping (RFLM) algorithm ensuring a continuous and unique reconstruction of field lines at any point of the 3D boundary. The reversibility property has a strong impact on the efficiency of modeling the highly anisotropic plasma edge transport in general closed or open configurations of arbitrary ergodicity as it avoids artificial cross-field diffusion of the fast parallel transport. For stellarator-symmetric magnetic configurations, which are the standard case for stellarators, the reversibility additionally provides an average cancellation of the radial interpolation errors of field lines circulating around closed magnetic flux surfaces. The RFLM technique has been implemented in the 3D edge transport code EMC3-EIRENE and is used routinely for plasma transport modeling in the boundaries of several low-shear and high-shear stellarators as well as in the boundary of a tokamak with 3D magnetic edge perturbations

  3. Data compression and genomes: a two-dimensional life domain map.

    Science.gov (United States)

    Menconi, Giulia; Benci, Vieri; Buiatti, Marcello

    2008-07-21

    We define the complexity of DNA sequences as the information content per nucleotide, calculated by means of some Lempel-Ziv data compression algorithm. It is possible to use the statistics of the complexity values of the functional regions of different complete genomes to distinguish among genomes of different domains of life (Archaea, Bacteria and Eukarya). We shall focus on the distribution function of the complexity of non-coding regions. We show that the three domains may be plotted in separate regions within the two-dimensional space where the axes are the skewness coefficient and the curtosis coefficient of the aforementioned distribution. Preliminary results on 15 genomes are introduced.

  4. Omnidirectional photonic band gap enlarged by one-dimensional ternary unmagnetized plasma photonic crystals based on a new Fibonacci quasiperiodic structure

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Haifeng [College of Electronic and Information Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Nanjing Artillery Academy, Nanjing 211132 (China); Liu Shaobin [College of Electronic and Information Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); State Key Laboratory of Millimeter Waves of Southeast University, Nanjing Jiangsu 210096 (China); Kong Xiangkun; Bian Borui; Dai Yi [College of Electronic and Information Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China)

    2012-11-15

    In this paper, an omnidirectional photonic band gap realized by one-dimensional ternary unmagnetized plasma photonic crystals based on a new Fibonacci quasiperiodic structure, which is composed of homogeneous unmagnetized plasma and two kinds of isotropic dielectric, is theoretically studied by the transfer matrix method. It has been shown that such an omnidirectional photonic band gap originates from Bragg gap in contrast to zero-n gap or single negative (negative permittivity or negative permeability) gap, and it is insensitive to the incidence angle and the polarization of electromagnetic wave. From the numerical results, the frequency range and central frequency of omnidirectional photonic band gap can be tuned by the thickness and density of the plasma but cease to change with increasing Fibonacci order. The bandwidth of omnidirectional photonic band gap can be notably enlarged. Moreover, the plasma collision frequency has no effect on the bandwidth of omnidirectional photonic band gap. It is shown that such new structure Fibonacci quasiperiodic one-dimensional ternary plasma photonic crystals have a superior feature in the enhancement of frequency range of omnidirectional photonic band gap compared with the conventional ternary and conventional Fibonacci quasiperiodic ternary plasma photonic crystals.

  5. Two-dimensional disruption thermal analysis code DREAM

    International Nuclear Information System (INIS)

    Yamazaki, Seiichiro; Kobayashi, Takeshi; Seki, Masahiro.

    1988-08-01

    When a plasma disruption takes place in a tokamak type fusion reactor, plasma facing components such as first wall and divertor/limiter are subjected to an intense heat load with very high heat flux and short duration. At the surface of the wall, temperature rapidly rises, and melting and evaporation occurs, it causes reduction of wall thickness and crack initiation/propagation. As lifetime of the components is significantly affected by them, the transient analysis in consideration of phase changes (melting/evaporation) and radiation heat loss is required in the design of these components. This paper describes the computer code DREAM developed to perform the two-dimensional transient thermal analysis that takes phase changes and radiation into account. The input and output of the code and a sample analysis on a disruption simulation experiment are also reported. The user's input manual is added as an appendix. The profiles and time variations of temperature, and melting and evaporated thicknesses of the material subjected to intense heat load can be obtained, using this computer code. This code also gives the temperature data for elastoplastic analysis with FEM structural analysis codes (ADINA, MARC, etc.) to evaluate the thermal stress and crack propagation behavior within the wall materials. (author)

  6. Two-dimensional beam profiles and one-dimensional projections

    Science.gov (United States)

    Findlay, D. J. S.; Jones, B.; Adams, D. J.

    2018-05-01

    One-dimensional projections of improved two-dimensional representations of transverse profiles of particle beams are proposed for fitting to data from harp-type monitors measuring beam profiles on particle accelerators. Composite distributions, with tails smoothly matched on to a central (inverted) parabola, are shown to give noticeably better fits than single gaussian and single parabolic distributions to data from harp-type beam profile monitors all along the proton beam transport lines to the two target stations on the ISIS Spallation Neutron Source. Some implications for inferring beam current densities on the beam axis are noted.

  7. Topotactic transformations of superstructures: from thin films to two-dimensional networks to nested two-dimensional networks.

    Science.gov (United States)

    Guo, Chuan Fei; Cao, Sihai; Zhang, Jianming; Tang, Haoying; Guo, Shengming; Tian, Ye; Liu, Qian

    2011-06-01

    Design and synthesis of super-nanostructures is one of the key and prominent topics in nanotechnology. Here we propose a novel methodology for synthesizing complex hierarchical superstructures using sacrificial templates composed of ordered two-dimensional (2D) nanostructures through lattice-directed topotactic transformations. The fabricated superstructures are nested 2D orthogonal Bi(2)S(3) networks composed of nanorods. Further investigation indicates that the lattice matching between the product and sacrificial template is the dominant mechanism for the formation of the superstructures, which agrees well with the simulation results based on an anisotropic nucleation and growth analysis. Our approach may provide a promising way toward a lattice-directed nonlithographic nanofabrication technique for making functional porous nanoarchitectures and electronic devices. © 2011 American Chemical Society

  8. Four-dimensional imaging of the initial stage of fast evolving plasmas

    International Nuclear Information System (INIS)

    Zhu Pengfei; Wang Weimin; Zhang Zhongchao; Chen Long; Zheng Jun; Li Runze; Qian Dong; Li Junjie; Wang Xuan; Cao Jianming; Sheng Zhengming; Zhang Jie

    2010-01-01

    Using an ultrafast electron probe capable of four-dimensional diagnosis, the initial stage of fast evolving plasmas produced by a 10 14 W/cm 2 laser irradiation of a metal target was investigated in real time with picosecond time resolution. The associated strong transient electric field was identified to have two components, which either focus or defocus the probe electron beam. The effects of this field on the probe electron beam can be reproduced by a self-expanding charge cloud containing about 5x10 7 suprathermal electrons with the outermost layer expanding at an average speed of 1.2x10 7 m/s.

  9. Lie algebra contractions on two-dimensional hyperboloid

    International Nuclear Information System (INIS)

    Pogosyan, G. S.; Yakhno, A.

    2010-01-01

    The Inoenue-Wigner contraction from the SO(2, 1) group to the Euclidean E(2) and E(1, 1) group is used to relate the separation of variables in Laplace-Beltrami (Helmholtz) equations for the four corresponding two-dimensional homogeneous spaces: two-dimensional hyperboloids and two-dimensional Euclidean and pseudo-Euclidean spaces. We show how the nine systems of coordinates on the two-dimensional hyperboloids contracted to the four systems of coordinates on E 2 and eight on E 1,1 . The text was submitted by the authors in English.

  10. Quasi-two-dimensional holography

    International Nuclear Information System (INIS)

    Kutzner, J.; Erhard, A.; Wuestenberg, H.; Zimpfer, J.

    1980-01-01

    The acoustical holography with numerical reconstruction by area scanning is memory- and time-intensive. With the experiences by the linear holography we tried to derive a scanning for the evaluating of the two-dimensional flaw-sizes. In most practical cases it is sufficient to determine the exact depth extension of a flaw, whereas the accuracy of the length extension is less critical. For this reason the applicability of the so-called quasi-two-dimensional holography is appropriate. The used sound field given by special probes is divergent in the inclined plane and light focussed in the perpendicular plane using cylindrical lenses. (orig.) [de

  11. Three-dimensional simulation study of compact toroid injection into magnetized plasmas

    International Nuclear Information System (INIS)

    Yoshio Suzuki; Tomohiko Watanabe; Tetsuya Sato; Takaya Hayashi

    1999-01-01

    Three-dimensional dynamics of a compact toroid (CT), which is injected into a magnetized target plasma modeling a part of a fusion device is investigated by using magnetohydrodynamic numerical simulations. It is found that the injected CT penetrates into the device region, suffering from a tilting instability. In this process, magnetic reconnection between the CT magnetic field and the device magnetic field takes place, which disrupts the magnetic configuration of the CT. As a result, the high density plasma confined in the CT magnetic field is locally supplied in the device region. Furthermore, the authors examine the penetration depth of the CT high density plasma. And it is revealed that the CT high density plasma is decelerated by the device magnetic field through the compressional heating

  12. Simulation of a two-dimensional sheath over a flat insulator-conductor interface on a radio-frequency biased electrode in a high-density plasma

    International Nuclear Information System (INIS)

    Kim, Doosik; Economou, Demetre J.

    2004-01-01

    A combined fluid/Monte Carlo (MC) simulation was developed to study the two-dimensional (2D) sheath over a flat insulator/conductor interface on a radio-frequency (rf) biased electrode in a high-density plasma. The insulator capacitance increased the local impedance between the plasma and the bias voltage source. Thus, for uniform ion density and electron temperature far away from the wall, the sheath potential over the insulator was only a fraction of that over the conductor, resulting in a thinner sheath over the insulator. The fluid model provided the spatiotemporal profiles of the 2D sheath electric field. These were used as input to the MC simulation to compute the ion energy distribution (IED) and ion angular distribution (IAD) at different locations on the surface. The ion flux, IED, and IAD changed drastically across the insulator/conductor interface due to the diverging rf electric field in the distorted sheath. The ion flux was larger on the conductor at the expense of that on the insulator. Both the ion impact angle and angular spread increased progressively as the material interface was approached. The ion impact energy and energy spread were smaller on the insulator as compared to the conductor. For given plasma parameters, as the insulator thickness was increased, the sheath potential and thickness over the insulator decreased, and sheath distortion became more pronounced

  13. Topology optimization of two-dimensional waveguides

    DEFF Research Database (Denmark)

    Jensen, Jakob Søndergaard; Sigmund, Ole

    2003-01-01

    In this work we use the method of topology optimization to design two-dimensional waveguides with low transmission loss.......In this work we use the method of topology optimization to design two-dimensional waveguides with low transmission loss....

  14. Traditional Semiconductors in the Two-Dimensional Limit.

    Science.gov (United States)

    Lucking, Michael C; Xie, Weiyu; Choe, Duk-Hyun; West, Damien; Lu, Toh-Ming; Zhang, S B

    2018-02-23

    Interest in two-dimensional materials has exploded in recent years. Not only are they studied due to their novel electronic properties, such as the emergent Dirac fermion in graphene, but also as a new paradigm in which stacking layers of distinct two-dimensional materials may enable different functionality or devices. Here, through first-principles theory, we reveal a large new class of two-dimensional materials which are derived from traditional III-V, II-VI, and I-VII semiconductors. It is found that in the ultrathin limit the great majority of traditional binary semiconductors studied (a series of 28 semiconductors) are not only kinetically stable in a two-dimensional double layer honeycomb structure, but more energetically stable than the truncated wurtzite or zinc-blende structures associated with three dimensional bulk. These findings both greatly increase the landscape of two-dimensional materials and also demonstrate that in the double layer honeycomb form, even ordinary semiconductors, such as GaAs, can exhibit exotic topological properties.

  15. Two-dimensional Nonlinear Simulations of Temperature-anisotropy Instabilities with a Proton-alpha Drift

    Science.gov (United States)

    Markovskii, S. A.; Chandran, Benjamin D. G.; Vasquez, Bernard J.

    2018-04-01

    We present two-dimensional hybrid simulations of proton-cyclotron and mirror instabilities in a proton-alpha plasma with particle-in-cell ions and a neutralizing electron fluid. The instabilities are driven by the protons with temperature perpendicular to the background magnetic field larger than the parallel temperature. The alpha particles with initially isotropic temperature have a nonzero drift speed with respect to the protons. The minor ions are known to influence the relative effect of the proton-cyclotron and mirror instabilities. In this paper, we show that the mirror mode can dominate the power spectrum at the nonlinear stage even if its linear growth rate is significantly lower than that of the proton-cyclotron mode. The proton-cyclotron instability combined with the alpha-proton drift is a possible cause of the nonzero magnetic helicity observed in the solar wind for fluctuations propagating nearly parallel to the magnetic field. Our simulations generally confirm this concept but reveal a complex helicity spectrum that is not anticipated from the linear theory of the instability.

  16. Structural comparison of complexes of methotrexate analogues with Lactobacillus casei dihydrofolate reductase by two-dimensional 1H NMR at 500 MHz

    International Nuclear Information System (INIS)

    Hammond, S.J.; Birdsall, B.; Feeney, J.; Searle, M.S.; Roberts, G.C.K.; Cheung, H.T.A.

    1987-01-01

    The authors have used two-dimensional (2D) NMR methods to examine complexes of Lactobacillus casei dihydrofolate reductase and methotrexate (MTX) analogues having structural modifications of the benzoyl ring and also the glutamic acid moiety. Assignments of the 1 H signals in the spectra of the various complexes were made by comparison of their 2D spectra with those complexes containing methotrexate where we have previously assigned resonances from 32 of the 162 amino acid residues. In the complexes formed with the dihalomethotrexate analogues, the glutamic acid and pteridine ring moieties were shown to bind to the enzyme in a manner similar to that found in the methotrexate-enzyme complex. Perturbations in 1 H chemical shifts of protons in Phe-49, Leu-54, and Leu-27 and the methotrexate H7 and NMe protons were observed in the different complexes and were accounted for by changes in orientation of the benzoyl ring in the various complexes. Binding of oxidized or reduced coenzyme to the binary complexes did not result in different shifts for Leu-27, Leu-54, or Leu-19 protons, and thus, the orientation of the benzoyl ring of the methotrexate analogues is not perturbed greatly by the presence of either oxidized or reduced coenzyme. In the complex with the γ-monoamide analog, the 1 H signals of assigned residues in the protein had almost identical shifts with the corresponding protons in the methotrexate-enzyme complex for all residues except His-28 and, to a lesser extent, Leu-27. This indicates that while the His-28 interaction with the MTX γ-CO 2 - is no longer present in this complex with the γ-amide, there has not been a major change in the overall structure of the two complexes. This behavior contrasts to that of the α-amide complex where 1 H signals from protons in several amino acid residues are different compared with their values in the complex formed with methotrexate

  17. Sufficient Controllability Condition for Affine Systems with Two-Dimensional Control and Two-Dimensional Zero Dynamics

    Directory of Open Access Journals (Sweden)

    D. A. Fetisov

    2015-01-01

    Full Text Available The controllability conditions are well known if we speak about linear stationary systems: a linear stationary system is controllable if and only if the dimension of the state vector is equal to the rank of the controllability matrix. The concept of the controllability matrix is extended to affine systems, but relations between affine systems controllability and properties of this matrix are more complicated. Various controllability conditions are set for affine systems, but they deal as usual either with systems of some special form or with controllability in some small neighborhood of the concerned point. An affine system is known to be controllable if the system is equivalent to a system of a canonical form, which is defined and regular in the whole space of states. In this case, the system is said to be feedback linearizable in the space of states. However there are examples, which illustrate that a system can be controllable even if it is not feedback linearizable in any open subset in the space of states. In this article we deal with such systems.Affine systems with two-dimensional control are considered. The system in question is assumed to be equivalent to a system of a quasicanonical form with two-dimensional zero dynamics which is defined and regular in the whole space of states. Therefore the controllability of the original system is equivalent to the controllability of the received system of a quasicanonical form. In this article the sufficient condition for an available solution of the terminal problem is proven for systems of a quasicanonical form with two-dimensional control and two-dimensional zero dynamics. The condition is valid in the case of an arbitrary time interval and arbitrary initial and finite states of the system. Therefore the controllability condition is set for systems of a quasicanonical form with two-dimensional control and two-dimensional zero dynamics. An example is given which illustrates how the proved

  18. Enthalpy probe measurements and three-dimensional modelling on air plasma jets generated by a non-transferred plasma torch with hollow electrodes

    International Nuclear Information System (INIS)

    Kim, Keun Su; Park, Jin Myung; Choi, Sooseok; Kim, Jongin; Hong, Sang Hee

    2008-01-01

    the numerical studies based on magnetohydrodynamics (MHD) theory, a precise three-dimensional transient numerical model for the internal arc discharge plasma of the torch has been developed along with a practical two-dimensional stationary one for the external thermal plasma jet by considering highly localized distributions of arc roots with circumferential non-uniformity on the electrode wall surfaces, so that more reliable and realistic descriptions on the arc thermal plasma properties become feasible both inside and outside the torch. The numerical calculation results are compared with the experimental data obtained from the probe measurements and found to be in good agreement with them

  19. Many-particle correlations in quasi-two-dimensional electron-hole systems

    International Nuclear Information System (INIS)

    Nikolaev, Valentin

    2002-01-01

    This thesis reports a theoretical investigation of many-particle correlation effects in semiconductor heterostructures containing quantum wells. Particular attention is paid towards quasi-particle pair correlations. Using the Green's function technique and the ladder approximation as a basis, the generalized mass action law, which describes the redistribution of particles between correlated and uncorrelated states in quasi-two-dimensional systems for different temperatures and total densities, is derived. The expression is valid beyond the low-density limit, which allows us to investigate the transition of the system from a dilute exciton gas to a dense electron-hole plasma. A generalized Levinson theorem, which takes k-space filling into account, is formulated. Screening in quasi-two-dimensional systems is analyzed rigorously. Firstly, the qualitatively new mechanism of static local screening by indirect excitons is studied using the simple Thomas-Fermi approximation. Then, a detailed many-body description suitable for a proper account of dynamic screening by a quasi-2D electron-hole plasma, and consistent with the previously derived mass action law, is provided. The generalized Lindhard approximation and excitonic plasmon-pole approximations are also derived. The theory is applied to single and double quantum wells. A self-consistent procedure is developed for numerical investigation of the ionization degree of an electron-hole plasma at different values of temperature/exciton Rydberg ratios. This procedure accounts for screening, k-space filling (exciton bleaching), and the formation of excitons. An abrupt jump in the value of the ionization degree that happens with an increase of the carrier density or temperature (Mott transition) is found in a certain density-temperature region. It has been found that the critical density of the Mott transition for indirect excitons may be much smaller than that for direct excitons. A suggestion has been made that some of the

  20. Numerical simulations of thermal conductivity in dissipative two-dimensional Yukawa systems.

    Science.gov (United States)

    Khrustalyov, Yu V; Vaulina, O S

    2012-04-01

    Numerical data on the heat transfer constants in two-dimensional Yukawa systems were obtained. Numerical study of the thermal conductivity and diffusivity was carried out for the equilibrium systems with parameters close to conditions of laboratory experiments with dusty plasma. For calculations of heat transfer constants the Green-Kubo formulas were used. The influence of dissipation (friction) on the heat transfer processes in nonideal systems was investigated. The approximation of the coefficient of thermal conductivity is proposed. Comparison of the obtained results to the existing experimental and numerical data is discussed.

  1. New Approach for Segmentation and Quantification of Two-Dimensional Gel Electrophoresis Images

    DEFF Research Database (Denmark)

    Anjo, Antonio dos; Laurell Blom Møller, Anders; Ersbøll, Bjarne Kjær

    2011-01-01

    Motivation: Detection of protein spots in two-dimensional gel electrophoresis images (2-DE) is a very complex task and current approaches addressing this problem still suffer from significant shortcomings. When quantifying a spot, most of the current software applications include a lot of backgro...

  2. A novel hybrid color image encryption algorithm using two complex chaotic systems

    Science.gov (United States)

    Wang, Leyuan; Song, Hongjun; Liu, Ping

    2016-02-01

    Based on complex Chen and complex Lorenz systems, a novel color image encryption algorithm is proposed. The larger chaotic ranges and more complex behaviors of complex chaotic systems, which compared with real chaotic systems could additionally enhance the security and enlarge key space of color image encryption. The encryption algorithm is comprised of three step processes. In the permutation process, the pixels of plain image are scrambled via two-dimensional and one-dimensional permutation processes among RGB channels individually. In the diffusion process, the exclusive-or (XOR for short) operation is employed to conceal pixels information. Finally, the mixing RGB channels are used to achieve a multilevel encryption. The security analysis and experimental simulations demonstrate that the proposed algorithm is large enough to resist the brute-force attack and has excellent encryption performance.

  3. Two-dimensional wavelet transform feature extraction for porous silicon chemical sensors.

    Science.gov (United States)

    Murguía, José S; Vergara, Alexander; Vargas-Olmos, Cecilia; Wong, Travis J; Fonollosa, Jordi; Huerta, Ramón

    2013-06-27

    Designing reliable, fast responding, highly sensitive, and low-power consuming chemo-sensory systems has long been a major goal in chemo-sensing. This goal, however, presents a difficult challenge because having a set of chemo-sensory detectors exhibiting all these aforementioned ideal conditions are still largely un-realizable to-date. This paper presents a unique perspective on capturing more in-depth insights into the physicochemical interactions of two distinct, selectively chemically modified porous silicon (pSi) film-based optical gas sensors by implementing an innovative, based on signal processing methodology, namely the two-dimensional discrete wavelet transform. Specifically, the method consists of using the two-dimensional discrete wavelet transform as a feature extraction method to capture the non-stationary behavior from the bi-dimensional pSi rugate sensor response. Utilizing a comprehensive set of measurements collected from each of the aforementioned optically based chemical sensors, we evaluate the significance of our approach on a complex, six-dimensional chemical analyte discrimination/quantification task problem. Due to the bi-dimensional aspects naturally governing the optical sensor response to chemical analytes, our findings provide evidence that the proposed feature extractor strategy may be a valuable tool to deepen our understanding of the performance of optically based chemical sensors as well as an important step toward attaining their implementation in more realistic chemo-sensing applications. Copyright © 2013 Elsevier B.V. All rights reserved.

  4. Analysis of Maneuvering Targets with Complex Motions by Two-Dimensional Product Modified Lv’s Distribution for Quadratic Frequency Modulation Signals

    Directory of Open Access Journals (Sweden)

    Fulong Jing

    2017-06-01

    Full Text Available For targets with complex motion, such as ships fluctuating with oceanic waves and high maneuvering airplanes, azimuth echo signals can be modeled as multicomponent quadratic frequency modulation (QFM signals after migration compensation and phase adjustment. For the QFM signal model, the chirp rate (CR and the quadratic chirp rate (QCR are two important physical quantities, which need to be estimated. For multicomponent QFM signals, the cross terms create a challenge for detection, which needs to be addressed. In this paper, by employing a novel multi-scale parametric symmetric self-correlation function (PSSF and modified scaled Fourier transform (mSFT, an effective parameter estimation algorithm is proposed—referred to as the Two-Dimensional product modified Lv’s distribution (2D-PMLVD—for QFM signals. The 2D-PMLVD is simple and can be easily implemented by using fast Fourier transform (FFT and complex multiplication. These measures are analyzed in the paper, including the principle, the cross term, anti-noise performance, and computational complexity. Compared to the other three representative methods, the 2D-PMLVD can achieve better anti-noise performance. The 2D-PMLVD, which is free of searching and has no identifiability problems, is more suitable for multicomponent situations. Through several simulations and analyses, the effectiveness of the proposed estimation algorithm is verified.

  5. A novel four-dimensional analytical approach for analysis of complex samples.

    Science.gov (United States)

    Stephan, Susanne; Jakob, Cornelia; Hippler, Jörg; Schmitz, Oliver J

    2016-05-01

    A two-dimensional LC (2D-LC) method, based on the work of Erni and Frei in 1978, was developed and coupled to an ion mobility-high-resolution mass spectrometer (IM-MS), which enabled the separation of complex samples in four dimensions (2D-LC, ion mobility spectrometry (IMS), and mass spectrometry (MS)). This approach works as a continuous multiheart-cutting LC system, using a long modulation time of 4 min, which allows the complete transfer of most of the first - dimension peaks to the second - dimension column without fractionation, in comparison to comprehensive two-dimensional liquid chromatography. Hence, each compound delivers only one peak in the second dimension, which simplifies the data handling even when ion mobility spectrometry as a third and mass spectrometry as a fourth dimension are introduced. The analysis of a plant extract from Ginkgo biloba shows the separation power of this four-dimensional separation method with a calculated total peak capacity of more than 8700. Furthermore, the advantage of ion mobility for characterizing unknown compounds by their collision cross section (CCS) and accurate mass in a non-target approach is shown for different matrices like plant extracts and coffee. Graphical abstract Principle of the four-dimensional separation.

  6. Two-dimensional flexible nanoelectronics

    Science.gov (United States)

    Akinwande, Deji; Petrone, Nicholas; Hone, James

    2014-12-01

    2014/2015 represents the tenth anniversary of modern graphene research. Over this decade, graphene has proven to be attractive for thin-film transistors owing to its remarkable electronic, optical, mechanical and thermal properties. Even its major drawback--zero bandgap--has resulted in something positive: a resurgence of interest in two-dimensional semiconductors, such as dichalcogenides and buckled nanomaterials with sizeable bandgaps. With the discovery of hexagonal boron nitride as an ideal dielectric, the materials are now in place to advance integrated flexible nanoelectronics, which uniquely take advantage of the unmatched portfolio of properties of two-dimensional crystals, beyond the capability of conventional thin films for ubiquitous flexible systems.

  7. Two dimensional analytical considerations of large magnetic and electric fields in laser produced plasmas

    International Nuclear Information System (INIS)

    Eliezer, S.; Loeb, A.

    1985-08-01

    A simple model in two dimensions is developed and solved analytically taking into account the electric and magnetic fields in laser procuded plasmas. The electric potential in this model is described by a nonlinear differential equation. The stationary solution of this model is consistent for -0.1 less than or equal to psi 6 v/cm]/[B/MGauss] approx. 1

  8. Spontaneous creation of nonzero-angular-momentum modes in tunnel-coupled two-dimensional degenerate Bose gases

    International Nuclear Information System (INIS)

    Montgomery, T. W. A.; Scott, R. G.; Lesanovsky, I.; Fromhold, T. M.

    2010-01-01

    We investigate the dynamics of two tunnel-coupled two-dimensional degenerate Bose gases. The reduced dimensionality of the clouds enables us to excite specific angular momentum modes by tuning the coupling strength, thereby creating striking patterns in the atom density profile. The extreme sensitivity of the system to the coupling and initial phase difference results in a rich variety of subsequent dynamics, including vortex production, complex oscillations in relative atom number, and chiral symmetry breaking due to counter-rotation of the two clouds.

  9. Row—column visibility graph approach to two-dimensional landscapes

    International Nuclear Information System (INIS)

    Xiao Qin; Pan Xue; Li Xin-Li; Stephen Mutua; Yang Hui-Jie; Jiang Yan; Wang Jian-Yong; Zhang Qing-Jun

    2014-01-01

    A new concept, called the row—column visibility graph, is proposed to map two-dimensional landscapes to complex networks. A cluster coverage is introduced to describe the extensive property of node clusters on a Euclidean lattice. Graphs mapped from fractals generated with the probability redistribution model behave scale-free. They have pattern-induced hierarchical organizations and comparatively much more extensive structures. The scale-free exponent has a negative correlation with the Hurst exponent, however, there is no deterministic relation between them. Graphs for fractals generated with the midpoint displacement model are exponential networks. When the Hurst exponent is large enough (e.g., H > 0.5), the degree distribution decays much more slowly, the average coverage becomes significant large, and the initially hierarchical structure at H < 0.5 is destroyed completely. Hence, the row—column visibility graph can be used to detect the pattern-related new characteristics of two-dimensional landscapes. (interdisciplinary physics and related areas of science and technology)

  10. NMRKIN: Simulating line shapes from two-dimensional spectra of proteins upon ligand binding

    International Nuclear Information System (INIS)

    Guenther, Ulrich L.; Schaffhausen, Brian

    2002-01-01

    The analysis of the shape of signals in NMR spectra is a powerful tool to study exchange and reaction kinetics. Line shapes in two-dimensional spectra of proteins recorded for titrations with ligands provide information about binding rates observed at individual residues. Here we describe a fast method to simulate a series of line shapes derived from two-dimensional spectra of a protein during a ligand titration. This procedure, which takes the mutual effects of two dimensions into account, has been implemented in MATLAB as an add-on to NMRLab (Guenther et al., 2000). In addition, more complex kinetic models, including sequential and parallel reactions, were simulated to demonstrate common features of more complex line shapes which could be encountered in protein-ligand interactions. As an example of this method, we describe its application to line shapes obtained for a titration of the p85 N-SH2 domain of PI3-kinase with a peptide derived from polyomavirus middle T antigen (MT)

  11. Dilepton production from the quark-gluon plasma using (3 +1 )-dimensional anisotropic dissipative hydrodynamics

    Science.gov (United States)

    Ryblewski, Radoslaw; Strickland, Michael

    2015-07-01

    We compute dilepton production from the deconfined phase of the quark-gluon plasma using leading-order (3 +1 )-dimensional anisotropic hydrodynamics. The anisotropic hydrodynamics equations employed describe the full spatiotemporal evolution of the transverse temperature, spheroidal momentum-space anisotropy parameter, and the associated three-dimensional collective flow of the matter. The momentum-space anisotropy is also taken into account in the computation of the dilepton production rate, allowing for a self-consistent description of dilepton production from the quark-gluon plasma. For our final results, we present predictions for high-energy dilepton yields as a function of invariant mass, transverse momentum, and pair rapidity. We demonstrate that high-energy dilepton production is extremely sensitive to the assumed level of initial momentum-space anisotropy of the quark-gluon plasma. As a result, it may be possible to experimentally constrain the early-time momentum-space anisotropy of the quark-gluon plasma generated in relativistic heavy-ion collisions using high-energy dilepton yields.

  12. One- and two-dimensional density and temperature measurements of an argon-neon Z-pinch plasma at stagnation

    International Nuclear Information System (INIS)

    Wong, K.L.; Springer, P.T.; Hammer, J.H.; Iglesias, C.A.; Osterheld, A.L.; Foord, M.E.; Bruns, H.C.; Emig, J.A.; Deeney, C.

    1996-10-01

    In order to benchmark and improve current 2D radiation magnetohydrodynamic (MHD) models of Z-pinch plasmas, we have performed experiments which characterize the plasma -conditions at stagnation. In the experiments the SATURN pulsed power facility at Sandia National Laboratory was used to create an imploding -Ar-Ne plasma. An absolutely calibrated, high resolution space- and time- resolving Johann crystal spectrometer was used to infer the electron temperature Te from the slope of the hydrogenlike Ne free-bound continuum, and the ion density ni from the Stark broadening of the Ar heliunlike Rydberg series. 2D electron temperature profiles of the plasma are obtained from a set of imaging crystals also focused on the Ne free-bound continuum. We shot two types of gas nozzles in the experiment, annular and uniform fill which varies the amount of mass in the plasma. 2D local thermodynamic equilibrium (LTE) and non-LTE MM models predict a radiating region denser and cooler than measured

  13. Predicting transition in two- and three-dimensional separated flows

    International Nuclear Information System (INIS)

    Cutrone, L.; De Palma, P.; Pascazio, G.; Napolitano, M.

    2008-01-01

    This paper is concerned with the numerical prediction of two- and three-dimensional transitional separated flows of turbomachinery interest. The recently proposed single-point transition model based on the use of a laminar kinetic energy transport equation is considered, insofar as it does not require to evaluate any integral parameter, such as boundary-layer thickness, and is thus directly applicable to three-dimensional flows. A well established model, combining a transition-onset correlation with an intermittency transport equation, is also used for comparison. Both models are implemented within a Reynolds-averaged Navier-Stokes solver employing a low-Reynolds-number k-ω turbulence model. The performance of the transition models have been evaluated and tested versus well-documented incompressible flows past a flat plate with semi-circular leading edge, namely: tests T3L2, T3L3, T3L5, and T3LA1 of ERCOFTAC, with different Reynolds numbers and free-stream conditions, the last one being characterized by a non-zero pressure gradient. In all computations, the first model has proven as adequate as or superior to the second one and has been then applied with success to two more complex test cases, for which detailed experimental data are available in the literature, namely: the two- and three-dimensional flows through the T106 linear turbine cascade

  14. Terahertz magneto-optical spectroscopy of a two-dimensional hole gas

    Energy Technology Data Exchange (ETDEWEB)

    Kamaraju, N., E-mail: nkamaraju@lanl.gov; Taylor, A. J.; Prasankumar, R. P., E-mail: rpprasan@lanl.gov [Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Pan, W.; Reno, J. [Sandia National Laboratories, Albuquerque, New Mexico 87123 (United States); Ekenberg, U. [Semiconsultants, Brunnsgrnd 12, SE-18773 Täby (Sweden); Gvozdić, D. M. [School of Electrical Engineering, University of Belgrade, Belgrade 11120 (Serbia); Boubanga-Tombet, S. [Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-Ku, Sendai (Japan); Upadhya, P. C. [Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Laboratory for Electro-Optics Systems, Indian Space Research Organization, Bangalore 560058 (India)

    2015-01-19

    Two-dimensional hole gases (2DHGs) have attracted recent attention for their unique quantum physics and potential applications in areas including spintronics and quantum computing. However, their properties remain relatively unexplored, motivating the use of different techniques to study them. We used terahertz magneto-optical spectroscopy to investigate the cyclotron resonance frequency in a high mobility 2DHG, revealing a nonlinear dependence on the applied magnetic field. This is shown to be due to the complex non-parabolic valence band structure of the 2DHG, as verified by multiband Landau level calculations. We also find that impurity scattering dominates cyclotron resonance decay in the 2DHG, in contrast with the dominance of superradiant damping in two-dimensional electron gases. Our results shed light on the properties of 2DHGs, motivating further studies of these unique 2D nanosystems.

  15. Two-dimensional topological field theories coupled to four-dimensional BF theory

    International Nuclear Information System (INIS)

    Montesinos, Merced; Perez, Alejandro

    2008-01-01

    Four-dimensional BF theory admits a natural coupling to extended sources supported on two-dimensional surfaces or string world sheets. Solutions of the theory are in one to one correspondence with solutions of Einstein equations with distributional matter (cosmic strings). We study new (topological field) theories that can be constructed by adding extra degrees of freedom to the two-dimensional world sheet. We show how two-dimensional Yang-Mills degrees of freedom can be added on the world sheet, producing in this way, an interactive (topological) theory of Yang-Mills fields with BF fields in four dimensions. We also show how a world sheet tetrad can be naturally added. As in the previous case the set of solutions of these theories are contained in the set of solutions of Einstein's equations if one allows distributional matter supported on two-dimensional surfaces. These theories are argued to be exactly quantizable. In the context of quantum gravity, one important motivation to study these models is to explore the possibility of constructing a background-independent quantum field theory where local degrees of freedom at low energies arise from global topological (world sheet) degrees of freedom at the fundamental level

  16. Phonons in a one-dimensional Yukawa chain: Dusty plasma experiment and model

    International Nuclear Information System (INIS)

    Liu Bin; Goree, J.

    2005-01-01

    Phonons in a one-dimensional chain of charged microspheres suspended in a plasma were studied in an experiment. The phonons correspond to random particle motion in the chain; no external manipulation was applied to excite the phonons. Two modes were observed, longitudinal and transverse. The velocity fluctuations in the experiment are analyzed using current autocorrelation functions and a phonon spectrum. The phonon energy was found to be unequally partitioned among phonon modes in the dusty plasma experiment. The experimental phonon spectrum was characterized by a dispersion relation that was found to differ from the dispersion relation for externally excited phonons. This difference is attributed to the presence of frictional damping due to gas, which affects the propagation of externally excited phonons differently from phonons that correspond to random particle motion. A model is developed and fit to the experiment to explain the features of the autocorrelation function, phonon spectrum, and the dispersion relation

  17. Statistical mechanics of two-dimensional and geophysical flows

    International Nuclear Information System (INIS)

    Bouchet, Freddy; Venaille, Antoine

    2012-01-01

    The theoretical study of the self-organization of two-dimensional and geophysical turbulent flows is addressed based on statistical mechanics methods. This review is a self-contained presentation of classical and recent works on this subject; from the statistical mechanics basis of the theory up to applications to Jupiter’s troposphere and ocean vortices and jets. Emphasize has been placed on examples with available analytical treatment in order to favor better understanding of the physics and dynamics. After a brief presentation of the 2D Euler and quasi-geostrophic equations, the specificity of two-dimensional and geophysical turbulence is emphasized. The equilibrium microcanonical measure is built from the Liouville theorem. Important statistical mechanics concepts (large deviations and mean field approach) and thermodynamic concepts (ensemble inequivalence and negative heat capacity) are briefly explained and described. On this theoretical basis, we predict the output of the long time evolution of complex turbulent flows as statistical equilibria. This is applied to make quantitative models of two-dimensional turbulence, the Great Red Spot and other Jovian vortices, ocean jets like the Gulf-Stream, and ocean vortices. A detailed comparison between these statistical equilibria and real flow observations is provided. We also present recent results for non-equilibrium situations, for the studies of either the relaxation towards equilibrium or non-equilibrium steady states. In this last case, forces and dissipation are in a statistical balance; fluxes of conserved quantity characterize the system and microcanonical or other equilibrium measures no longer describe the system.

  18. Post-cardiac arrest level of free-plasma DNA and DNA-histone complexes

    DEFF Research Database (Denmark)

    Jeppesen, A N; Hvas, A-M; Grejs, A M

    2017-01-01

    Background Plasma DNA-histone complexes and total free-plasma DNA have the potential to quantify the ischaemia-reperfusion damages occurring after cardiac arrest. Furthermore, DNA-histone complexes may have the potential of being a target for future treatment. The aim was to examine if plasma DNA-histone...... after 22, 46 and 70 h. Samples for DNA-histone complexes were quantified by Cell Death Detection ELISAplus. The total free-plasma DNA analyses were quantified with qPCR by analysing the Beta-2 microglobulin gene. The control group comprised 40 healthy individuals. Results We found no difference...... in the level of DNA-histone complexes between the 22-h sample and healthy individuals (P = 0.10). In the 46-h sample, there was an increased level of DNA-histone complexes in non-survivors compared with survivors 30 days after the cardiac arrest (P

  19. Complex of two-dimensional multigroup programs for neutron-physical computations of nuclear reactor

    International Nuclear Information System (INIS)

    Karpov, V.A.; Protsenko, A.N.

    1975-01-01

    Briefly stated mathematical aspects of the two-dimensional multigroup method of neutron-physical computation of nuclear reactor. Problems of algorithmization and BESM-6 computer realisation of multigroup diffuse approximations in hexagonal and rectangular calculated lattices are analysed. The results of computation of fast critical assembly having complicated composition of the core are given. The estimation of computation accuracy of criticality, neutron fields distribution and efficiency of absorbing rods by means of computer programs developed is done. (author)

  20. Two-dimensional modeling of x-ray output from switched foil implosions on Procyon

    Science.gov (United States)

    Bowers, R. L.; Nakafuji, G.; Greene, A. E.; McLenithan, K. D.; Peterson, D. L.; Roderick, N. F.

    1996-09-01

    A series of two-dimensional radiation magnetohydrodynamic calculations are presented of a Z-pinch implosion using a plasma flow switch. Results from a recent experiment using the high explosive driven generator Procyon, which delivered 16.5 MA to a plasma flow switch and switched about 15 MA into a static load, are used to study the implosion of a 29 mg load foil [J. H. Goforth et al., ``Review of the Procyon Explosive Pulsed Power System,'' in Ninth IEEE Pulsed Power Conference, June 1993, Albuquerque, edited by K. R. Prestwich and W. L. Baker (Institute of Electrical and Electronics Engineers, Piscataway, NJ, 1993), p. 36]. The interaction of the switch with the load plasma and the effects of background plasma on the total radiation output is examined. Models which assume ideal switching are also included. Also included are the effects of perturbations in the load plasma which may be associated with initial vaporization of the load foil. If the background plasma density in the switch region and in the load region does not affect the dynamics, the pinch is predicted to produce a total radiation output of about 4 MJ. Including perturbations of the load plasma associated with switching and assuming a background plasma density after switching in excess of 10-7 g/cm3 results in a total output from the pinch of about 0.6 MJ.

  1. Effect of two-temperature electrons distribution on an electrostatic plasma sheath

    International Nuclear Information System (INIS)

    Ou, Jing; Xiang, Nong; Gan, Chunyun; Yang, Jinhong

    2013-01-01

    A magnetized collisionless plasma sheath containing two-temperature electrons is studied using a one-dimensional model in which the low-temperature electrons are described by Maxwellian distribution (MD) and high-temperature electrons are described by truncated Maxwellian distribution (TMD). Based on the ion wave approach, a modified sheath criterion including effect of TMD caused by high-temperature electrons energy above the sheath potential energy is established theoretically. The model is also used to investigate numerically the sheath structure and energy flux to the wall for plasmas parameters of an open divertor tokamak-like. Our results show that the profiles of the sheath potential, two-temperature electrons and ions densities, high-temperature electrons and ions velocities as well as the energy flux to the wall depend on the high-temperature electrons concentration, temperature, and velocity distribution function associated with sheath potential. In addition, the results obtained in the high-temperature electrons with TMD as well as with MD sheaths are compared for the different sheath potential

  2. A two-dimensional regularization algorithm for density profile evaluation from broadband reflectometry

    International Nuclear Information System (INIS)

    Nunes, F.; Varela, P.; Silva, A.; Manso, M.; Santos, J.; Nunes, I.; Serra, F.; Kurzan, B.; Suttrop, W.

    1997-01-01

    Broadband reflectometry is a current technique that uses the round-trip group delays of reflected frequency-swept waves to measure density profiles of fusion plasmas. The main factor that may limit the accuracy of the reconstructed profiles is the interference of the probing waves with the plasma density fluctuations: plasma turbulence leads to random phase variations and magneto hydrodynamic activity produces mainly strong amplitude and phase modulations. Both effects cause the decrease, and eventually loss, of signal at some frequencies. Several data processing techniques can be applied to filter and/or interpolate noisy group delay data obtained from turbulent plasmas with a single frequency sweep. Here, we propose a more powerful algorithm performing two-dimensional regularization (in space and time) of data provided by multiple consecutive frequency sweeps, which leads to density profiles with improved accuracy. The new method is described and its application to simulated data corrupted by noise and missing data is considered. It is shown that the algorithm improves the identification of slowly varying plasma density perturbations by attenuating the effect of fast fluctuations and noise contained in experimental data. First results obtained with this method in ASDEX Upgrade tokamak are presented. copyright 1997 American Institute of Physics

  3. Beginning Introductory Physics with Two-Dimensional Motion

    Science.gov (United States)

    Huggins, Elisha

    2009-01-01

    During the session on "Introductory College Physics Textbooks" at the 2007 Summer Meeting of the AAPT, there was a brief discussion about whether introductory physics should begin with one-dimensional motion or two-dimensional motion. Here we present the case that by starting with two-dimensional motion, we are able to introduce a considerable…

  4. Two-dimensional thermofield bosonization

    International Nuclear Information System (INIS)

    Amaral, R.L.P.G.; Belvedere, L.V.; Rothe, K.D.

    2005-01-01

    The main objective of this paper was to obtain an operator realization for the bosonization of fermions in 1 + 1 dimensions, at finite, non-zero temperature T. This is achieved in the framework of the real-time formalism of Thermofield Dynamics. Formally, the results parallel those of the T = 0 case. The well-known two-dimensional Fermion-Boson correspondences at zero temperature are shown to hold also at finite temperature. To emphasize the usefulness of the operator realization for handling a large class of two-dimensional quantum field-theoretic problems, we contrast this global approach with the cumbersome calculation of the fermion-current two-point function in the imaginary-time formalism and real-time formalisms. The calculations also illustrate the very different ways in which the transmutation from Fermi-Dirac to Bose-Einstein statistics is realized

  5. Two-dimensional x-ray diffraction

    CERN Document Server

    He, Bob B

    2009-01-01

    Written by one of the pioneers of 2D X-Ray Diffraction, this useful guide covers the fundamentals, experimental methods and applications of two-dimensional x-ray diffraction, including geometry convention, x-ray source and optics, two-dimensional detectors, diffraction data interpretation, and configurations for various applications, such as phase identification, texture, stress, microstructure analysis, crystallinity, thin film analysis and combinatorial screening. Experimental examples in materials research, pharmaceuticals, and forensics are also given. This presents a key resource to resea

  6. Extensions of the 3-dimensional plasma transport code E3D

    International Nuclear Information System (INIS)

    Runov, A.; Schneider, R.; Kasilov, S.; Reiter, D.

    2004-01-01

    One important aspect of modern fusion research is plasma edge physics. Fluid transport codes extending beyond the standard 2-D code packages like B2-Eirene or UEDGE are under development. A 3-dimensional plasma fluid code, E3D, based upon the Multiple Coordinate System Approach and a Monte Carlo integration procedure has been developed for general magnetic configurations including ergodic regions. These local magnetic coordinates lead to a full metric tensor which accurately accounts for all transport terms in the equations. Here, we discuss new computational aspects of the realization of the algorithm. The main limitation to the Monte Carlo code efficiency comes from the restriction on the parallel jump of advancing test particles which must be small compared to the gradient length of the diffusion coefficient. In our problems, the parallel diffusion coefficient depends on both plasma and magnetic field parameters. Usually, the second dependence is much more critical. In order to allow long parallel jumps, this dependence can be eliminated in two steps: first, the longitudinal coordinate x 3 of local magnetic coordinates is modified in such a way that in the new coordinate system the metric determinant and contra-variant components of the magnetic field scale along the magnetic field with powers of the magnetic field module (like in Boozer flux coordinates). Second, specific weights of the test particles are introduced. As a result of increased parallel jump length, the efficiency of the code is about two orders of magnitude better. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  7. Two dimensional, two fluid model for sodium boiling in LMFBR fuel assemblies

    International Nuclear Information System (INIS)

    Granziera, M.R.; Kazimi, M.S.

    1980-05-01

    A two dimensional numerical model for the simulation of sodium boiling transient was developed using the two fluid set of conservation equations. A semiimplicit numerical differencing scheme capable of handling the problems associated with the ill-posedness implied by the complex characteristic roots of the two fluid problems was used, which took advantage of the dumping effect of the exchange terms. Of particular interest in the development of the model was the identification of the numerical problems caused by the strong disparity between the axial and radial dimensions of fuel assemblies. A solution to this problem was found which uses the particular geometry of fuel assemblies to accelerate the convergence of the iterative technique used in the model. Three sodium boiling experiments were simulated with the model, with good agreement between the experimental results and the model predictions

  8. Modelling of three dimensional equilibrium and stability of MAST plasmas with magnetic perturbations using VMEC and COBRA

    Energy Technology Data Exchange (ETDEWEB)

    Ham, C. J., E-mail: christopher.ham@ccfe.ac.uk; Chapman, I. T.; Kirk, A.; Saarelma, S. [CCFE, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom)

    2014-10-15

    It is known that magnetic perturbations can mitigate edge localized modes (ELMs) in experiments, for example, MAST [Kirk et al., Nucl. Fusion 53, 043007 (2013)]. One hypothesis is that the magnetic perturbations cause a three dimensional corrugation of the plasma and this corrugated plasma has different stability properties to peeling-ballooning modes compared to an axisymmetric plasma. It has been shown in an up-down symmetric plasma that magnetic perturbations in tokamaks will break the usual axisymmetry of the plasma causing three dimensional displacements [Chapman et al., Plasma Phys. Controlled Fusion 54, 105013 (2012)]. We produce a free boundary three-dimensional equilibrium of a lower single null MAST relevant plasma using VMEC [S. P. Hirshman and J. C. Whitson, Phys. Fluids 26, 3553 (1983)]. The safety factor and pressure profiles used for the modelling are similar to those deduced from axisymmetric analysis of experimental data with ELMs. We focus on the effect of applying n = 3 and n = 6 magnetic perturbations using the resonant magnetic perturbation (RMP) coils. A midplane displacement of over ±1 cm is seen when the full current is applied. The current in the coils is scanned and a linear relationship between coil current and midplane displacement is found. The pressure gradient in real space in different toroidal locations is shown to change when RMPs are applied. This effect should be taken into account when diagnosing plasmas with RMPs applied. The helical Pfirsch-Schlüter currents which arise as a result of the assumption of nested flux surfaces are estimated for this equilibrium. The effect of this non-axisymmetric equilibrium on infinite n ballooning stability is investigated using COBRA [Sanchez et al., J. Comput. Phys. 161, 576–588 (2000)]. The infinite n ballooning stability is analysed for two reasons; it may give an indication of the effect of non-axisymmetry on finite n peeling-ballooning modes, responsible for ELMs; and

  9. Comparative study of two- and three-dimensional modeling on arc discharge phenomena inside a thermal plasma torch with hollow electrodes

    International Nuclear Information System (INIS)

    Kim, Keun Su; Park, Jin Myung; Choi, Sooseok; Kim, Jongin; Hong, Sang Hee

    2008-01-01

    A comparative study between two- and three-dimensional (2D and 3D) modeling is carried out on arc discharge phenomena inside a thermal plasma torch with hollow electrodes, in order to evaluate the effects of arc root configuration characterized by either 2D annular or 3D highly localized attachment on the electrode surface. For this purpose, a more precise 3D transient model has been developed by taking account of 3D arc current distribution and arc root rotation. The 3D simulation results apparently reveal that the 3D arc root attachment brings about the inherent 3D and turbulence nature of plasma fields inside the torch. It is also found that the constricted arc column near the vortex chamber plays an important role in heating and acceleration of injected arc gases by concentrating arc currents on the axis of the hollow electrodes. The inherent 3D nature of arc discharge is well preserved inside the cathode region, while these 3D features slowly diminish behind the vortex chamber where the turbulent flow begins to be developed in the anode region. Based on the present simulation results, it is noted that the mixing effects of the strong turbulent flow on the heat and mass transfer are mainly responsible for the gradual relaxation of the 3D structures of plasma fields into the 2D axisymmetric ones that eventually appear in the anode region near the torch exit. From a detailed comparison of the 3D results with the 2D ones, the arc root configuration seems to have a significant effect on the heat transfer to the electrode surfaces interacting with the turbulent plasma flow. That is, in the 2D simulation based on an axisymmetric stationary model, the turbulence phenomena are fairly underestimated and the amount of heat transferred to the cold anode wall is calculated to be smaller than that obtained in the 3D simulation. For the validation of the numerical simulations, calculated plasma temperatures and axial velocities are compared with experimentally measured ones

  10. Piezoelectricity in Two-Dimensional Materials

    KAUST Repository

    Wu, Tao

    2015-02-25

    Powering up 2D materials: Recent experimental studies confirmed the existence of piezoelectricity - the conversion of mechanical stress into electricity - in two-dimensional single-layer MoS2 nanosheets. The results represent a milestone towards embedding low-dimensional materials into future disruptive technologies. © 2015 Wiley-VCH Verlag GmbH & Co. KGaA.

  11. Integration of the three-dimensional Vlasov equation for a magnetized plasma

    International Nuclear Information System (INIS)

    Cheng, C.Z.

    1976-04-01

    A second order splitting scheme is developed to integrate the three dimensional Vlasov equation for a plasma in a magnetic field. The integration of the Vlasov equation is divided into a series of intermediate steps and Fourier interpolation and the ASD method with a third order Taylor expansion are used to integrate the fractional equations. Numerical experiments related to cyclotron waves in 2 and 2 1 / 2 D are demonstrated with high accuracy and efficiency. The computer storage requirements are modest; for example, a typical 2D nonlinear electron plasma simulation requires only 4000 ''particles.''

  12. CD163: a signal receptor scavenging haptoglobin-hemoglobin complexes from plasma

    DEFF Research Database (Denmark)

    Graversen, Jonas Heilskov; Madsen, Mette; Moestrup, Søren K

    2002-01-01

    as the endocytic receptor binding hemoglobin (Hb) in complex with the plasma protein haptoglobin (Hp). This specific receptor-ligand interaction leading to removal from plasma of the Hp-Hb complex-but not free Hp or Hb-now explains the depletion of circulating Hp in individuals with increased intravascular...

  13. Three-dimensional structure of a pre-catalytic human spliceosomal complex B.

    Science.gov (United States)

    Boehringer, Daniel; Makarov, Evgeny M; Sander, Bjoern; Makarova, Olga V; Kastner, Berthold; Lührmann, Reinhard; Stark, Holger

    2004-05-01

    Major structural changes occur in the spliceosome during its transition from the fully assembled complex B to the catalytically activated spliceosome. To understand the rearrangement, it is necessary to know the detailed three-dimensional structures of these complexes. Here, we have immunoaffinity-purified human spliceosomes (designated B Delta U1) at a stage after U4/U6.U5 tri-snRNP integration but before activation, and have determined the three-dimensional structure of B Delta U1 by single-particle electron cryomicroscopy at a resolution of approximately 40 A. The overall size of the complex is about 370 x 270 x 170 A. The three-dimensional structure features a roughly triangular body linked to a head domain in variable orientations. The body is very similar in size and shape to the isolated U4/U6.U5 tri-snRNP. This provides initial insight into the structural organization of complex B.

  14. One- and two-dimensional density and temperature measurements of an argon-neon Z-pinch plasma at stagnation

    International Nuclear Information System (INIS)

    Wong, K.L.; Springer, P.T.; Hammer, J.H.; Iglesias, C.A.; Osterheld, A.L.; Foord, M.E.; Bruns, H.C.; Emig, J.A.; Deeney, C.

    1997-01-01

    In order to benchmark and improve current 2D radiation magnetohydrodynamic (MHD) models of Z-pinch plasmas, we have performed experiments which characterize the plasma conditions at stagnation. In the experiments the SATURN pulsed power facility at Sandia National Laboratory was used to create an imploding Ar-Ne plasma. An absolutely calibrated, high resolution space- and time-resolving Johann crystal spectrometer was used to infer the electron temperature T e from the slope of the hydrogenlike Ne free-bound continuum, and the ion density n i from the Stark broadening of the Ar heliumlike Rydberg series. 2D electron temperature profiles of the plasma are obtained from a set of imaging crystals also focused on the Ne free-bound continuum. We shot two types of gas nozzles in the experiment, annular and uniform fill, which varies the amount of mass in the plasma. 2D local thermodynamic equilibrium (LTE) and non-LTE MHD models predict a radiating region denser and cooler than measured. copyright 1997 American Institute of Physics

  15. Bispectral experimental estimation of the nonlinear energy transfer in two-dimensional plasma turbulence

    DEFF Research Database (Denmark)

    Manz, P.; Ramisch, M.; Stroth, U.

    2008-01-01

    Experimental density and potential fluctuation data from a 2D probe array have been analysed to study the turbulent cascade in a toroidally confined magnetized plasma. The bispectral analysis technique used is from Ritz et al ( 1989 Phys. Fluids B 1 153) and Kim et al ( 1996 Phys. Plasmas 3 3998...... scales. This is the first experimental evidence for the dual turbulent cascade in a magnetized plasma....

  16. Two-dimensional confinement of heavy fermions

    International Nuclear Information System (INIS)

    Shishido, Hiroaki; Shibauchi, Takasada; Matsuda, Yuji; Terashima, Takahito

    2010-01-01

    Metallic systems with the strongest electron correlations are realized in certain rare-earth and actinide compounds whose physics are dominated by f-electrons. These materials are known as heavy fermions, so called because the effective mass of the conduction electrons is enhanced via correlation effects up to as much as several hundreds times the free electron mass. To date the electronic structure of all heavy-fermion compounds is essentially three-dimensional. Here we report on the first realization of a two-dimensional heavy-fermion system, where the dimensionality is adjusted in a controllable fashion by fabricating heterostructures using molecular beam epitaxy. The two-dimensional heavy fermion system displays striking deviations from the standard Fermi liquid low-temperature electronic properties. (author)

  17. A heuristic two-dimensional presentation of microsatellite-based data applied to dogs and wolves

    Directory of Open Access Journals (Sweden)

    Foerster Martin

    2007-07-01

    Full Text Available Abstract Methods based on genetic distance matrices usually lose information during the process of tree-building by converting a multi-dimensional matrix into a phylogenetic tree. We applied a heuristic method of two-dimensional presentation to achieve a better resolution of the relationship between breeds and individuals investigated. Four hundred and nine individuals from nine German dog breed populations and one free-living wolf population were analysed with a marker set of 23 microsatellites. The result of the two-dimensional presentation was partly comparable with and complemented a model-based analysis that uses genotype patterns. The assignment test and the neighbour-joining tree based on allele sharing estimate allocated 99% and 97% of the individuals according to their breed, respectively. The application of the two-dimensional presentation to distances on the basis of the proportion of shared alleles resulted in comparable and further complementary insight into inferred population structure by multilocus genotype data. We expect that the inference of population structure in domesticated species with complex breeding histories can be strongly supported by the two-dimensional presentation based on the described heuristic method.

  18. Two-dimensional topological photonics

    Science.gov (United States)

    Khanikaev, Alexander B.; Shvets, Gennady

    2017-12-01

    Originating from the studies of two-dimensional condensed-matter states, the concept of topological order has recently been expanded to other fields of physics and engineering, particularly optics and photonics. Topological photonic structures have already overturned some of the traditional views on wave propagation and manipulation. The application of topological concepts to guided wave propagation has enabled novel photonic devices, such as reflection-free sharply bent waveguides, robust delay lines, spin-polarized switches and non-reciprocal devices. Discrete degrees of freedom, widely used in condensed-matter physics, such as spin and valley, are now entering the realm of photonics. In this Review, we summarize the latest advances in this highly dynamic field, with special emphasis on the experimental work on two-dimensional photonic topological structures.

  19. Structures of two-dimensional three-body systems

    International Nuclear Information System (INIS)

    Ruan, W.Y.; Liu, Y.Y.; Bao, C.G.

    1996-01-01

    Features of the structure of L = 0 states of a two-dimensional three-body model system have been investigated. Three types of permutation symmetry of the spatial part, namely symmetric, antisymmetric, and mixed, have been considered. A comparison has been made between the two-dimensional system and the corresponding three-dimensional one. The effect of symmetry on microscopic structures is emphasized. (author)

  20. Fine structure of modal focusing effect in a three dimensional plasma-sheath-lens formed by disk electrodes

    DEFF Research Database (Denmark)

    Stamate, Eugen; Yamaguchi, Masahito

    2015-01-01

    Modal and discrete focusing effects associated with three-dimensional plasma-sheath-lenses show promising potential for applications in ion beam extraction, mass spectrometry, plasma diagnostics and for basic studies of plasma sheath. The ion focusing properties can be adjusted by controlling the...

  1. Unruly topologies in two-dimensional quantum gravity

    International Nuclear Information System (INIS)

    Hartle, J.B.

    1985-01-01

    A sum over histories formulation of quantum geometry could involve sums over different topologies as well as sums over different metrics. In classical gravity a geometry is a manifold with a metric, but it is difficult to implement a sum over manifolds in quantum gravity. In this difficulty, motivation is found for including in the sum over histories, geometries defined on more general objects than manifolds-unruly topologies. In simplicial two-dimensional quantum gravity a class of simplicial complexes is found to which the gravitational action can be extended, for which sums over the class are straightforwardly defined, and for which a manifold dominates the sum in the classical limit. The situation in higher dimensions is discussed. (author)

  2. X-ray imaging device for one-dimensional and two-dimensional radioscopy

    International Nuclear Information System (INIS)

    1978-01-01

    The X-ray imaging device for the selectable one-dimensional or two-dimensional pictures of objects illuminated by X-rays, comprising an X-ray source, an X-ray screen, and an opto-electrical picture development device placed behind the screen, is characterized by an anamorphotic optical system, which is positioned with a one-dimensional illumination between the X-ray screen and the opto-electrical device and that a two-dimensional illumination will be developed, and that in view of the lens system which forms part of the opto-electrical device, there is placed an X-ray screen in a specified beam direction so that a magnified image may be formed by equalisation of the distance between the X-ray screen and the lens system. (G.C.)

  3. Hamiltonian formalism of two-dimensional Vlasov kinetic equation.

    Science.gov (United States)

    Pavlov, Maxim V

    2014-12-08

    In this paper, the two-dimensional Benney system describing long wave propagation of a finite depth fluid motion and the multi-dimensional Russo-Smereka kinetic equation describing a bubbly flow are considered. The Hamiltonian approach established by J. Gibbons for the one-dimensional Vlasov kinetic equation is extended to a multi-dimensional case. A local Hamiltonian structure associated with the hydrodynamic lattice of moments derived by D. J. Benney is constructed. A relationship between this hydrodynamic lattice of moments and the two-dimensional Vlasov kinetic equation is found. In the two-dimensional case, a Hamiltonian hydrodynamic lattice for the Russo-Smereka kinetic model is constructed. Simple hydrodynamic reductions are presented.

  4. Novel target design algorithm for two-dimensional optical storage (TwoDOS)

    NARCIS (Netherlands)

    Huang, Li; Chong, T.C.; Vijaya Kumar, B.V.K.; Kobori, H.

    2004-01-01

    In this paper we introduce the Hankel transform based channel model of Two-Dimensional Optical Storage (TwoDOS) system. Based on this model, the two-dimensional (2D) minimum mean-square error (MMSE) equalizer has been derived and applied to some simple but common cases. The performance of the 2D

  5. Visualization tool for three-dimensional plasma velocity distributions (ISEE_3D) as a plug-in for SPEDAS

    Science.gov (United States)

    Keika, Kunihiro; Miyoshi, Yoshizumi; Machida, Shinobu; Ieda, Akimasa; Seki, Kanako; Hori, Tomoaki; Miyashita, Yukinaga; Shoji, Masafumi; Shinohara, Iku; Angelopoulos, Vassilis; Lewis, Jim W.; Flores, Aaron

    2017-12-01

    This paper introduces ISEE_3D, an interactive visualization tool for three-dimensional plasma velocity distribution functions, developed by the Institute for Space-Earth Environmental Research, Nagoya University, Japan. The tool provides a variety of methods to visualize the distribution function of space plasma: scatter, volume, and isosurface modes. The tool also has a wide range of functions, such as displaying magnetic field vectors and two-dimensional slices of distributions to facilitate extensive analysis. The coordinate transformation to the magnetic field coordinates is also implemented in the tool. The source codes of the tool are written as scripts of a widely used data analysis software language, Interactive Data Language, which has been widespread in the field of space physics and solar physics. The current version of the tool can be used for data files of the plasma distribution function from the Geotail satellite mission, which are publicly accessible through the Data Archives and Transmission System of the Institute of Space and Astronautical Science (ISAS)/Japan Aerospace Exploration Agency (JAXA). The tool is also available in the Space Physics Environment Data Analysis Software to visualize plasma data from the Magnetospheric Multiscale and the Time History of Events and Macroscale Interactions during Substorms missions. The tool is planned to be applied to data from other missions, such as Arase (ERG) and Van Allen Probes after replacing or adding data loading plug-ins. This visualization tool helps scientists understand the dynamics of space plasma better, particularly in the regions where the magnetohydrodynamic approximation is not valid, for example, the Earth's inner magnetosphere, magnetopause, bow shock, and plasma sheet.

  6. Novel two-dimensional uranyl-organic assemblages in the citrate and D(-)-citramalate families

    International Nuclear Information System (INIS)

    Thuery, P.

    2008-01-01

    Uranyl nitrate reacts with D(-)-citramalic acid (H(3)citml) under mild hydrothermal conditions to give the two-dimensional polymer [UO 2 (Hcitml)] 1, in which each ligand chelates one metal atom through its hydroxyl and alpha- carboxylate groups and binds to three others in monodentate fashion. The resulting neutral layers display isolated uranyl pentagonal bipyramidal polyhedra. Whereas citric acid (H(4)cit) has been shown previously to give various three- and mono-dimensional uranyl organic assemblages, complexation under hydrothermal conditions in the presence of either NaOH/NEt 4 Cl or pyridine yields the complexes [NEt 4 ] 2 [(UO 2 ) 3 (cit) 2 (H 2 O) 2 ]· 2H 2 O 2 and [Hpy] 2 )[(UO 2 ) 3 (cit)(Hcit)(OH)] 3, respectively, which both crystallize as two- dimensional frameworks. The layers are either planar and separated by the counter ions in 2 or corrugated and hydrogen bonded to one another in 3. In both 2 and 3, [UO 2 (cit)] 2 4- dimeric subunits with edge-sharing pentagonal bipyramidal uranium coordination polyhedra are present but, in both cases and in contrast with previous structures containing [UO 2 (Hcit)] 2 2- dimers, the carboxylate group not involved in the dimer formation is coordinated to another uranyl unit, which is part of either a centrosymmetric hexagonal bipyramidal bis-aquated group or a different, [(UO 2 ) 2 (Hcit)(OH)] dimer. These examples of two- dimensional assemblages further illustrate the variety of architectures which can be obtained with citric and related acids and the important structure-directing effects of the counter ions. (author)

  7. Two-dimensional ferroelectrics

    Energy Technology Data Exchange (ETDEWEB)

    Blinov, L M; Fridkin, Vladimir M; Palto, Sergei P [A.V. Shubnikov Institute of Crystallography, Russian Academy of Sciences, Moscow, Russian Federaion (Russian Federation); Bune, A V; Dowben, P A; Ducharme, Stephen [Department of Physics and Astronomy, Behlen Laboratory of Physics, Center for Materials Research and Analysis, University of Nebraska-Linkoln, Linkoln, NE (United States)

    2000-03-31

    The investigation of the finite-size effect in ferroelectric crystals and films has been limited by the experimental conditions. The smallest demonstrated ferroelectric crystals had a diameter of {approx}200 A and the thinnest ferroelectric films were {approx}200 A thick, macroscopic sizes on an atomic scale. Langmuir-Blodgett deposition of films one monolayer at a time has produced high quality ferroelectric films as thin as 10 A, made from polyvinylidene fluoride and its copolymers. These ultrathin films permitted the ultimate investigation of finite-size effects on the atomic thickness scale. Langmuir-Blodgett films also revealed the fundamental two-dimensional character of ferroelectricity in these materials by demonstrating that there is no so-called critical thickness; films as thin as two monolayers (1 nm) are ferroelectric, with a transition temperature near that of the bulk material. The films exhibit all the main properties of ferroelectricity with a first-order ferroelectric-paraelectric phase transition: polarization hysteresis (switching); the jump in spontaneous polarization at the phase transition temperature; thermal hysteresis in the polarization; the increase in the transition temperature with applied field; double hysteresis above the phase transition temperature; and the existence of the ferroelectric critical point. The films also exhibit a new phase transition associated with the two-dimensional layers. (reviews of topical problems)

  8. Exploring the limits of cooperative phenomena using complex plasmas

    International Nuclear Information System (INIS)

    Schwabe, M.; Zhdanov, S.; Ivlev, A. V.; Thomas, H. M.; Morfill, G. E.

    2011-01-01

    With the advancing miniaturization of technological applications, processes on the mesoscale become increasingly important. This is the scale where the individual movement of particles transforms into cooperative behavior-behavior that cannot be explained by investigating the motion of individual particles alone.Complex plasmas are ideally suited to study the limits of cooperative behavior. The time scales of the dynamics of the microparticles embedded in the plasma are such that their movement can be fully resolved, and an investigation on the atomistic (kinetic) level is possible. In addition, complex plasmas can be considered a model system for ordinary fluids: The internal microparticle dynamics is basically undamped and is characterized by the similarity parameters matching those of other fluids. This similarity does not break down even at small scales: For instance, in [2], microparticle droplets comprised of only a few 1000-10000 particles were examined. In these experiments, the Weber number (the ratio of inertia to surface tension forces) matches that of falling water drops. As another example, the onset of a Rayleigh-Taylor instability in a complex plasma can be described by the ordinary dispersion relation, even at scales of only few particle layers. This allows investigating the 'nanoscale' of fluid flows, and, hence, the limits of cooperative behavior.

  9. Non-parametric comparison of histogrammed two-dimensional data distributions using the Energy Test

    International Nuclear Information System (INIS)

    Reid, Ivan D; Lopes, Raul H C; Hobson, Peter R

    2012-01-01

    When monitoring complex experiments, comparison is often made between regularly acquired histograms of data and reference histograms which represent the ideal state of the equipment. With the larger HEP experiments now ramping up, there is a need for automation of this task since the volume of comparisons could overwhelm human operators. However, the two-dimensional histogram comparison tools available in ROOT have been noted in the past to exhibit shortcomings. We discuss a newer comparison test for two-dimensional histograms, based on the Energy Test of Aslan and Zech, which provides more conclusive discrimination between histograms of data coming from different distributions than methods provided in a recent ROOT release.

  10. A Toroidally Symmetric Plasma Simulation code for design of position and shape control on tokamak plasmas

    International Nuclear Information System (INIS)

    Takase, Haruhiko; Senda, Ikuo

    1999-01-01

    A Toroidally Symmetric Plasma Simulation (TSPS) code has been developed for investigating the position and shape control on tokamak plasmas. The analyses of three-dimensional eddy currents on the conducting components around the plasma and the two-dimensional magneto-hydrodynamic (MHD) equilibrium are taken into account in this code. The code can analyze the plasma position and shape control during the minor disruption in which the deformation of plasma is not negligible. Using the ITER (International Thermonuclear Experimental Reactor) parameters, some examples of calculations are shown in this paper. (author)

  11. Two-dimensional plasma expansion in a magnetic nozzle: Separation due to electron inertia

    International Nuclear Information System (INIS)

    Ahedo, Eduardo; Merino, Mario

    2012-01-01

    A previous axisymmetric model of the supersonic expansion of a collisionless, hot plasma in a divergent magnetic nozzle is extended here in order to include electron-inertia effects. Up to dominant order on all components of the electron velocity, electron momentum equations still reduce to three conservation laws. Electron inertia leads to outward electron separation from the magnetic streamtubes. The progressive plasma filling of the adjacent vacuum region is consistent with electron-inertia being part of finite electron Larmor radius effects, which increase downstream and eventually demagnetize the plasma. Current ambipolarity is not fulfilled and ion separation can be either outwards or inwards of magnetic streamtubes, depending on their magnetization. Electron separation penalizes slightly the plume efficiency and is larger for plasma beams injected with large pressure gradients. An alternative nonzero electron-inertia model [E. Hooper, J. Propul. Power 9, 757 (1993)] based on cold plasmas and current ambipolarity, which predicts inwards electron separation, is discussed critically. A possible competition of the gyroviscous force with electron-inertia effects is commented briefly.

  12. Two-Dimensional Materials for Sensing: Graphene and Beyond

    Directory of Open Access Journals (Sweden)

    Seba Sara Varghese

    2015-09-01

    Full Text Available Two-dimensional materials have attracted great scientific attention due to their unusual and fascinating properties for use in electronics, spintronics, photovoltaics, medicine, composites, etc. Graphene, transition metal dichalcogenides such as MoS2, phosphorene, etc., which belong to the family of two-dimensional materials, have shown great promise for gas sensing applications due to their high surface-to-volume ratio, low noise and sensitivity of electronic properties to the changes in the surroundings. Two-dimensional nanostructured semiconducting metal oxide based gas sensors have also been recognized as successful gas detection devices. This review aims to provide the latest advancements in the field of gas sensors based on various two-dimensional materials with the main focus on sensor performance metrics such as sensitivity, specificity, detection limit, response time, and reversibility. Both experimental and theoretical studies on the gas sensing properties of graphene and other two-dimensional materials beyond graphene are also discussed. The article concludes with the current challenges and future prospects for two-dimensional materials in gas sensor applications.

  13. Development of innovative thermal plasma and particle diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Bachmann, Benjamin-Leon

    2013-09-24

    Three original plasma diagnostic systems have been developed to investigate transient three-dimensional plasma processes with high spatial and temporal resolution. The developed diagnostics have been analyzed and tested by increasing the complexity from a stationary free burning Argon arc to a dc pulsed process and finally to a transient gas metal arc including droplet transfer through the plasma. The transient plasma parameters that have been determined include three-dimensional axially symmetric plasma densities (n{sub e}, n{sub A}, n{sub A+}, n{sub A++}), electron temperatures (T{sub e}), electrical conductivities (σ{sub el}), magnetic flux densities (B) and current densities (j{sub el}). In the case of a droplet transfer through an arc consisting of an Iron/Argon plasma, the droplet density, surface tension, viscosity, and temperature have been determined.

  14. Forming three-dimensional closed shapes from two-dimensional soft ribbons by controlled buckling

    Science.gov (United States)

    Aoki, Michio; Juang, Jia-Yang

    2018-02-01

    Conventional manufacturing techniques-moulding, machining and casting-exist to produce three-dimensional (3D) shapes. However, these industrial processes are typically geared for mass production and are not directly applicable to residential settings, where inexpensive and versatile tools are desirable. Moreover, those techniques are, in general, not adequate to process soft elastic materials. Here, we introduce a new concept of forming 3D closed hollow shapes from two-dimensional (2D) elastic ribbons by controlled buckling. We numerically and experimentally characterize how the profile and thickness of the ribbon determine its buckled shape. We find a 2D master profile with which various elliptical 3D shapes can be formed. More complex natural and artificial hollow shapes, such as strawberry, hourglass and wheel, can also be achieved via strategic design and pattern engraving on the ribbons. The nonlinear response of the post-buckling regime is rationalized through finite-element analysis, which shows good quantitative agreement with experiments. This robust fabrication should complement conventional techniques and provide a rich arena for future studies on the mechanics and new applications of elastic hollow structures.

  15. Quasilinear diffusion in inhomogeneous plasmas

    International Nuclear Information System (INIS)

    Hooley, D.L.

    1975-05-01

    The problem of inhomogeneous diffusion in a plasma is considered with emphasis on its possible application to relativistic electron beams. A one-dimensional model with a background electrostatic field is used to illustrate the basic approach, which is then extended to a two-dimensional plasma with a background magnetic field. Only preliminary results are available. (U.S.)

  16. Two-dimensional calculus

    CERN Document Server

    Osserman, Robert

    2011-01-01

    The basic component of several-variable calculus, two-dimensional calculus is vital to mastery of the broader field. This extensive treatment of the subject offers the advantage of a thorough integration of linear algebra and materials, which aids readers in the development of geometric intuition. An introductory chapter presents background information on vectors in the plane, plane curves, and functions of two variables. Subsequent chapters address differentiation, transformations, and integration. Each chapter concludes with problem sets, and answers to selected exercises appear at the end o

  17. Phase transitions in two-dimensional systems

    International Nuclear Information System (INIS)

    Salinas, S.R.A.

    1983-01-01

    Some experiences are related using synchrotron radiation beams, to characterize solid-liquid (fusion) and commensurate solid-uncommensurate solid transitions in two-dimensional systems. Some ideas involved in the modern theories of two-dimensional fusion are shortly exposed. The systems treated consist of noble gases (Kr,Ar,Xe) adsorbed in the basal plane of graphite and thin films formed by some liquid crystal shells. (L.C.) [pt

  18. A new method of solution for one-dimensional quasi-neutral bounded plasmas

    Science.gov (United States)

    Kamran, M.; Kuhn, S.

    2010-08-01

    A new method is proposed for calculating the potential distribution Φ(z) in a one-dimensional quasi-neutral bounded plasma; Φ(z) is assumed to satisfy a quasi-neutrality condition (plasma equation) of the form ni{Φ(z)} = ne(Φ), where the electron density ne is a given function of Φ and the ion density ni is expressed in terms of trajectory integrals of the ion kinetic equation. While previous methods relied on formally solving a global integral equation (Riemann, Phys. Plasmas, vol. 13, 2006, paper no. 013503; Kos et al., Phys. Plasmas, vol. 16, 2009, paper no. 093503), the present method is characterized by piecewise analytic solution of the plasma equation in reasonably small intervals of z. As a first concrete application, Φ(z) is found analytically through order z4 near the center of a collisionless Tonks-Langmuir discharge with a cold-ion source.

  19. Fast-wave heating of a two-component plasma

    International Nuclear Information System (INIS)

    Stix, T.H.

    1975-02-01

    The use of the compressional hydromagnetic mode (also called the magnetosonic or, simply, the fast wave) is examined in some detail with respect to the heating of a tritium plasma containing a few percent deuterium. Efficient absorption of wave energy by the deuteron component is found when ω = ω/sub c/ (deuterons), with Q/sub wave/ greater than or equal to 100. The dominant behavior of the high-energy deuteron distribution function is found to be f(v) approximately exp[3/2) ∫/sup v/ dv less than Δv greater than/less than(Δv/sub perpendicular to/) 2 greater than], where [Δv] is the Chandrasekhar-Spitzer drag coefficient, and [(Δv/sub perpendicular to/) 2 sigma] is the Kennel-Englemann quasilinear diffusion coefficient for wave--particle interaction at the deuteron cyclotron frequency. An analytic solution to the one-dimensional Fokker--Planck equation, with rf-induced diffusion, is developed, and using this solution together with Duane's fit to the D-T fusion cross-section, it is found that the nuclear fusion power output from an rf-produced two-component plasma can significantly exceed the incremental (radiofrequency) power input. (auth)

  20. The theory of critical phenomena in two-dimensional systems

    International Nuclear Information System (INIS)

    Olvera de la C, M.

    1981-01-01

    An exposition of the theory of critical phenomena in two-dimensional physical systems is presented. The first six chapters deal with the mean field theory of critical phenomena, scale invariance of the thermodynamic functions, Kadanoff's spin block construction, Wilson's renormalization group treatment of critical phenomena in configuration space, and the two-dimensional Ising model on a triangular lattice. The second part of this work is made of four chapters devoted to the application of the ideas expounded in the first part to the discussion of critical phenomena in superfluid films, two-dimensional crystals and the two-dimensional XY model of magnetic systems. Chapters seven to ten are devoted to the following subjects: analysis of long range order in one, two, and three-dimensional physical systems. Topological defects in the XY model, in superfluid films and in two-dimensional crystals. The Thouless-Kosterlitz iterated mean field theory of the dipole gas. The renormalization group treatment of the XY model, superfluid films and two-dimensional crystal. (author)

  1. Numerical calculation on a two-step subdiffusion behavior of lateral protein movement in plasma membranes

    Science.gov (United States)

    Sumi, Tomonari; Okumoto, Atsushi; Goto, Hitoshi; Sekino, Hideo

    2017-10-01

    A two-step subdiffusion behavior of lateral movement of transmembrane proteins in plasma membranes has been observed by using single-molecule experiments. A nested double-compartment model where large compartments are divided into several smaller ones has been proposed in order to explain this observation. These compartments are considered to be delimited by membrane-skeleton "fences" and membrane-protein "pickets" bound to the fences. We perform numerical simulations of a master equation using a simple two-dimensional lattice model to investigate the heterogeneous diffusion dynamics behavior of transmembrane proteins within plasma membranes. We show that the experimentally observed two-step subdiffusion process can be described using fence and picket models combined with decreased local diffusivity of transmembrane proteins in the vicinity of the pickets. This allows us to explain the two-step subdiffusion behavior without explicitly introducing nested double compartments.

  2. On-stack two-dimensional conversion of MoS2 into MoO3

    Science.gov (United States)

    Yeoung Ko, Taeg; Jeong, Areum; Kim, Wontaek; Lee, Jinhwan; Kim, Youngchan; Lee, Jung Eun; Ryu, Gyeong Hee; Park, Kwanghee; Kim, Dogyeong; Lee, Zonghoon; Lee, Min Hyung; Lee, Changgu; Ryu, Sunmin

    2017-03-01

    Chemical transformation of existing two-dimensional (2D) materials can be crucial in further expanding the 2D crystal palette required to realize various functional heterostructures. In this work, we demonstrate a 2D ‘on-stack’ chemical conversion of single-layer crystalline MoS2 into MoO3 with a precise layer control that enables truly 2D MoO3 and MoO3/MoS2 heterostructures. To minimize perturbation of the 2D morphology, a nonthermal oxidation using O2 plasma was employed. The early stage of the reaction was characterized by a defect-induced Raman peak, drastic quenching of photoluminescence (PL) signals and sub-nm protrusions in atomic force microscopy images. As the reaction proceeded from the uppermost layer to the buried layers, PL and optical second harmonic generation signals showed characteristic modulations revealing a layer-by-layer conversion. The plasma-generated 2D oxides, confirmed as MoO3 by x-ray photoelectron spectroscopy, were found to be amorphous but extremely flat with a surface roughness of 0.18 nm, comparable to that of 1L MoS2. The rate of oxidation quantified by Raman spectroscopy decreased very rapidly for buried sulfide layers due to protection by the surface 2D oxides, exhibiting a pseudo-self-limiting behavior. As exemplified in this work, various on-stack chemical transformations can be applied to other 2D materials in forming otherwise unobtainable materials and complex heterostructures, thus expanding the palette of 2D material building blocks.

  3. Computer tomography of large dust clouds in complex plasmas

    International Nuclear Information System (INIS)

    Killer, Carsten; Himpel, Michael; Melzer, André

    2014-01-01

    The dust density is a central parameter of a dusty plasma. Here, a tomography setup for the determination of the three-dimensionally resolved density distribution of spatially extended dust clouds is presented. The dust clouds consist of micron-sized particles confined in a radio frequency argon plasma, where they fill almost the entire discharge volume. First, a line-of-sight integrated dust density is obtained from extinction measurements, where the incident light from an LED panel is scattered and absorbed by the dust. Performing these extinction measurements from many different angles allows the reconstruction of the 3D dust density distribution, analogous to a computer tomography in medical applications

  4. Three-dimensional plasma equilibrium model based on the poloidal representation of the magnetic field

    International Nuclear Information System (INIS)

    Gruber, R.; Degtyarev, L.M.; Kuper, A.; Martynov, A.A.; Medvedev, S.Yu.; Shafranov, V.D.

    1996-01-01

    Equations for the three-dimensional equilibrium of a plasma are formulated in the poloidal representation. The magnetic field is expressed in terms of the poloidal magnetic flux Ψ and the poloidal electric current F. As a result, three-dimensional equilibrium configurations are analyzed with the help of a set of equations including the elliptical equation for the poloidal flux, the magnetic differential equation for the parallel current, and the equations for the basis vector field b. To overcome the difficulties associated with peculiarities that can arise in solving the magnetic differential equation at rational toroidal magnetic surfaces, small regulating corrections are introduced into the proposed set of equations. In this case, second-order differential terms with a small parameter appear in the magnetic differential equations. As a result, these equations take the form of elliptical equations. Three versions of regulating corrections are proposed. The equations obtained can be used to develop numerical codes for calculating three-dimensional equilibrium plasma configurations with an island structure

  5. Formation of a three-dimensional plasma boundary after decay of the plasma response to resonant magnetic perturbation fields

    Science.gov (United States)

    Schmitz, O.; Evans, T. E.; Fenstermacher, M. E.; Lanctot, M. J.; Lasnier, C. L.; Mordijck, S.; Moyer, R. A.; Reimerdes, H.; the DIII-D Team

    2014-01-01

    First time experimental evidence is presented for a direct link between the decay of a n = 3 plasma response and the formation of a three-dimensional (3D) plasma boundary. We inspect a lower single-null L-mode plasma which first reacts at sufficiently high rotation with an ideal resonant screening response to an external toroidal mode number n = 3 resonant magnetic perturbation field. Decay of this response due to reduced bulk plasma rotation changes the plasma state considerably. Signatures such as density pump out and a spin up of the edge rotation—which are usually connected to formation of a stochastic boundary—are detected. Coincident, striation of the divertor single ionized carbon emission and a 3D emission structure in double ionized carbon at the separatrix is seen. The striated C II pattern follows in this stage the perturbed magnetic footprint modelled without a plasma response (vacuum approach). This provides for the first time substantial experimental evidence, that a 3D plasma boundary with direct impact on the divertor particle flux pattern is formed as soon as the internal plasma response decays. The resulting divertor structure follows the vacuum modelled magnetic field topology. However, the inward extension of the perturbed boundary layer can still not directly be determined from these measurements.

  6. Anisotropic confinement effects in a two-dimensional plasma crystal.

    Science.gov (United States)

    Laut, I; Zhdanov, S K; Räth, C; Thomas, H M; Morfill, G E

    2016-01-01

    The spectral asymmetry of the wave-energy distribution of dust particles during mode-coupling-induced melting, observed for the first time in plasma crystals by Couëdel et al. [Phys. Rev. E 89, 053108 (2014)PLEEE81539-375510.1103/PhysRevE.89.053108], is studied theoretically and by molecular-dynamics simulations. It is shown that an anisotropy of the well confining the microparticles selects the directions of preferred particle motion. The observed differences in intensity of waves of opposed directions are explained by a nonvanishing phonon flux. Anisotropic phonon scattering by defects and Umklapp scattering are proposed as possible reasons for the mean phonon flux.

  7. Approximate solutions for the two-dimensional integral transport equation. The critically mixed methods of resolution

    International Nuclear Information System (INIS)

    Sanchez, Richard.

    1980-11-01

    This work is divided into two part the first part (note CEA-N-2165) deals with the solution of complex two-dimensional transport problems, the second one treats the critically mixed methods of resolution. These methods are applied for one-dimensional geometries with highly anisotropic scattering. In order to simplify the set of integral equation provided by the integral transport equation, the integro-differential equation is used to obtain relations that allow to lower the number of integral equation to solve; a general mathematical and numerical study is presented [fr

  8. Particle modeling of plasmas computational plasma physics

    International Nuclear Information System (INIS)

    Dawson, J.M.

    1991-01-01

    Recently, through the development of supercomputers, a powerful new method for exploring plasmas has emerged; it is computer modeling of plasmas. Such modeling can duplicate many of the complex processes that go on in a plasma and allow scientists to understand what the important processes are. It helps scientists gain an intuition about this complex state of matter. It allows scientists and engineers to explore new ideas on how to use plasma before building costly experiments; it allows them to determine if they are on the right track. It can duplicate the operation of devices and thus reduce the need to build complex and expensive devices for research and development. This is an exciting new endeavor that is in its infancy, but which can play an important role in the scientific and technological competitiveness of the US. There are a wide range of plasma models that are in use. There are particle models, fluid models, hybrid particle fluid models. These can come in many forms, such as explicit models, implicit models, reduced dimensional models, electrostatic models, magnetostatic models, electromagnetic models, and almost an endless variety of other models. Here the author will only discuss particle models. He will give a few examples of the use of such models; these will be taken from work done by the Plasma Modeling Group at UCLA because he is most familiar with work. However, it only gives a small view of the wide range of work being done around the US, or for that matter around the world

  9. Study on the properties of tunable prohibited band gaps for one-dimensional ternary magnetized plasma photonic crystals

    International Nuclear Information System (INIS)

    Zhang Haifeng; Zheng Jianping; Zhu Rongjun

    2012-01-01

    The transfer matrix method was applied to study on the properties of tunable prohibited band gaps for one-dimensional ternary magnetized plasma photonic crystals with TE wave arbitrary incident under ideal conditions. TE wave would be divided into left-handed circularly polarized wave and right-handed circularly polarized wave after propagation through one-dimensional ternary magnetized plasma photonic crystals. The calculated transmission coefficients were used to analyze the effects of parameter of plasma, plasma filling factor, incident angle and relative dielectric constant for dielectric layer on the properties of tunable prohibited band gap. The results illustrate that the width of band gaps can not be broadened by increasing plasma collision frequency, the numbers and width of band gaps can be tuned by changing plasma frequency, plasma filling factor and relative dielectric constant for dielectric layer. The band gaps for right-handed circularly polarized wave can be tuned by the plasma gyro frequency, but band gaps for the left-handed circularly polarized wave can't influenced. Low-frequency region of band gaps will be broadened, while high-frequency region of band gaps will be firstly narrow and then broaden with increasing incident angle. (authors)

  10. Theory and application of a three-dimensional code SHAPS to complex piping systems

    International Nuclear Information System (INIS)

    Wang, C.Y.

    1983-01-01

    This paper describes the theory and application of a three-dimensional computer code SHAPS to the complex piping systems. The code utilizes a two-dimensional implicit Eulerian method for the hydrodynamic analysis together with a three-dimensional elastic-plastic finite-element program for the structural calculation. A three-dimensional pipe element with eight degrees of freedom is employed to account for the hoop, flexural, axial, and the torsional mode of the piping system. In the SHAPS analysis the hydrodynamic equations are modified to include the global piping motion. Coupling between fluid and structure is achieved by enforcing the free-slip boundary conditions. Also, the response of the piping network generated by the seismic excitation can be included. A thermal transient capability is also provided in SHAPS. To illustrate the methodology, many sample problems dealing with the hydrodynamic, structural, and thermal analyses of reactor-piping systems are given. Validation of the SHAPS code with experimental data is also presented

  11. Initial measurements of two- and three-dimensional ordering, waves, and plasma filamentation in the Magnetized Dusty Plasma Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Edward, E-mail: etjr@auburn.edu; Konopka, Uwe [Physics Department, Auburn University, Auburn, Alabama 36849 (United States); Merlino, Robert L. [Department of Physics and Astronomy, The University of Iowa, Iowa City, Iowa 52242 (United States); Rosenberg, Marlene [Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, California 92093 (United States)

    2016-05-15

    The Magnetized Dusty Plasma Experiment at Auburn University has been operational for over one year. In that time, a number of experiments have been performed at magnetic fields up to B = 2.5 T to explore the interaction between magnetized plasmas and charged, micron-sized dust particles. This paper reports on the initial results from studies of: (a) the formation of imposed, ordered structures, (b) the properties of dust wave waves in a rotating frame, and (c) the generation of plasma filaments.

  12. Two- and three-dimensional CT analysis of ankle fractures

    International Nuclear Information System (INIS)

    Magid, D.; Fishman, E.K.; Ney, D.R.; Kuhlman, J.E.

    1988-01-01

    CT with coronal and sagittal reformatting (two-dimensional CT) and animated volumetric image rendering (three-dimensional CT) was used to assess ankle fractures. Partial volume limits transaxial CT in assessments of horizontally oriented structures. Two-dimensional CT, being orthogonal to the plafond, superior mortise, talar dome, and tibial epiphysis, often provides the most clinically useful images. Two-dimensional CT is most useful in characterizing potentially confusing fractures, such as Tillaux (anterior tubercle), triplane, osteochondral talar dome, or nondisplaced talar neck fractures, and it is the best study to confirm intraarticular fragments. Two-and three-dimensional CT best indicate the percentage of articular surface involvement and best demonstrate postoperative results or complications (hardware migration, residual step-off, delayed union, DJD, AVN, etc). Animated three-dimensional images are the preferred means of integrating the two-dimensional findings for surgical planning, as these images more closely simulate the clinical problem

  13. On two-dimensionalization of three-dimensional turbulence in shell models

    DEFF Research Database (Denmark)

    Chakraborty, Sagar; Jensen, Mogens Høgh; Sarkar, A.

    2010-01-01

    Applying a modified version of the Gledzer-Ohkitani-Yamada (GOY) shell model, the signatures of so-called two-dimensionalization effect of three-dimensional incompressible, homogeneous, isotropic fully developed unforced turbulence have been studied and reproduced. Within the framework of shell m......-similar PDFs for longitudinal velocity differences are also presented for the rotating 3D turbulence case....

  14. Two-dimensional turbulent convection

    Science.gov (United States)

    Mazzino, Andrea

    2017-11-01

    We present an overview of the most relevant, and sometimes contrasting, theoretical approaches to Rayleigh-Taylor and mean-gradient-forced Rayleigh-Bénard two-dimensional turbulence together with numerical and experimental evidences for their support. The main aim of this overview is to emphasize that, despite the different character of these two systems, especially in relation to their steadiness/unsteadiness, turbulent fluctuations are well described by the same scaling relationships originated from the Bolgiano balance. The latter states that inertial terms and buoyancy terms balance at small scales giving rise to an inverse kinetic energy cascade. The main difference with respect to the inverse energy cascade in hydrodynamic turbulence [R. H. Kraichnan, "Inertial ranges in two-dimensional turbulence," Phys. Fluids 10, 1417 (1967)] is that the rate of cascade of kinetic energy here is not constant along the inertial range of scales. Thanks to the absence of physical boundaries, the two systems here investigated turned out to be a natural physical realization of the Kraichnan scaling regime hitherto associated with the elusive "ultimate state of thermal convection" [R. H. Kraichnan, "Turbulent thermal convection at arbitrary Prandtl number," Phys. Fluids 5, 1374-1389 (1962)].

  15. Advanced 3-dimensional electron kinetic calculations for the current drive problem in magnetically confined thermonuclear plasmas

    International Nuclear Information System (INIS)

    Peysson, Y.; Decker, J.; Bers, A.; Ram, A.; Harvey, R.

    2004-01-01

    Accurate and fast electron kinetic calculations is a challenging issue for realistic simulations of thermonuclear tokamak plasmas. Relativistic corrections and electron trajectory effects must be fully taken into account for high temperature burning plasmas, while codes should also consistently describe wave-particle resonant interactions in presence of locally large gradients close to internal transport barrier. In that case, neoclassical effects may come into play and self-consistent evaluation of both the radio-frequency and bootstrap currents must be performed. In addition, a complex interplay between momentum and radial electron dynamics may take place, in presence of a possible energy dependent radial transport. Besides the physics needs, there are considerable numerical issues to solve, in order to reduce computer time consumption and memory requirements at an acceptable level, so that kinetic calculations may be valuably incorporated in a chain of codes which determines plasma equilibrium and wave propagation. So far, fully implicit 3-dimensional calculations based on a finite difference scheme and an incomplete L and U matrices factorization have been found to be so most effective method to reach this goal. A review of the present status in this active field of physics is presented, with an emphasis on possible future improvements. (authors)

  16. Graphic system for the analysis of representation of a complex three-dimensional configuration for radiation shield calculation

    International Nuclear Information System (INIS)

    Berezhkov, A.B.; Gordeeva, E.K.; Mazanov, V.L.; Solov'ev, V.Yu.; Ryabov, A.V.; Khokhlov, V.F.; Shejno, I.N.

    1987-01-01

    Programs for obtaining phantom images when calculating the radiation shield structure for nuclear-engineering plants, using computer graphics, are developed. Programs are designed to accompany calculational investigations using the SUPER2/RRI3-PICSCH program and ZAMOK-TOMOGRAF program comutering complexes. Design geometry techniques, allowing to present three-dimensional object in the form of two-dimensional perspective projection to the screen plane, are realized in the programs

  17. Nonlinear behavior of a monochromatic wave in a one-dimensional Vlasov plasma

    International Nuclear Information System (INIS)

    Shoucri, M.M.; Gagne, R.R.J.

    1978-01-01

    The nonlinear evolution of a monochromatic wave in a one-dimensional Vlasov plasma is studied numerically. The numerical results are carried out far enough in time for phase mixing to dominate the asymptotic state of the system. A qualitative comparison with previously reported simulations is given

  18. Criteria governing electron plasma waves in a two-temperature plasma

    International Nuclear Information System (INIS)

    Dell, M.P.; Gledhill, I.M.A.; Hellberg, M.A.

    1987-01-01

    Using a technique based on the saddle-points of the dielectric function, criteria are found which govern the behaviour of electron plasma waves in plasmas with two electron populations having different temperatures. (orig.)

  19. Multi-perspective views of students’ difficulties with one-dimensional vector and two-dimensional vector

    Science.gov (United States)

    Fauzi, Ahmad; Ratna Kawuri, Kunthi; Pratiwi, Retno

    2017-01-01

    Researchers of students’ conceptual change usually collects data from written tests and interviews. Moreover, reports of conceptual change often simply refer to changes in concepts, such as on a test, without any identification of the learning processes that have taken place. Research has shown that students have difficulties with vectors in university introductory physics courses and high school physics courses. In this study, we intended to explore students’ understanding of one-dimensional and two-dimensional vector in multi perspective views. In this research, we explore students’ understanding through test perspective and interviews perspective. Our research study adopted the mixed-methodology design. The participants of this research were sixty students of third semester of physics education department. The data of this research were collected by testand interviews. In this study, we divided the students’ understanding of one-dimensional vector and two-dimensional vector in two categories, namely vector skills of the addition of one-dimensionaland two-dimensional vector and the relation between vector skills and conceptual understanding. From the investigation, only 44% of students provided correct answer for vector skills of the addition of one-dimensional and two-dimensional vector and only 27% students provided correct answer for the relation between vector skills and conceptual understanding.

  20. Viscosity of confined two-dimensional Yukawa liquids: A nonequilibrium method

    International Nuclear Information System (INIS)

    Landmann, S.; Kählert, H.; Thomsen, H.; Bonitz, M.

    2015-01-01

    We present a nonequilibrium method that allows one to determine the viscosity of two-dimensional dust clusters in an isotropic confinement. By applying a tangential external force to the outer parts of the cluster (e.g., with lasers), a sheared velocity profile is created. The decay of the angular velocity towards the center of the confinement potential is determined by a balance between internal (viscosity) and external friction (neutral gas damping). The viscosity can then be calculated from a fit of the measured velocity profile to a solution of the Navier-Stokes equation. Langevin dynamics simulations are used to demonstrate the feasibility of the method. We find good agreement of the measured viscosity with previous results for macroscopic Yukawa plasmas

  1. A two-dimensional kinetic model of the scrape-off layer

    International Nuclear Information System (INIS)

    Catto, P.J.; Hazeltine, R.D.

    1993-09-01

    A two-dimensional (radius and poloidal angle), analytically tractable kinetic model of the ion (or energetic electron) behavior in the scrape-off layer of a limiter or divertor plasma in a tokamak is presented. The model determines the boundary conditions on the core ion density and ion temperature gradients, the power load on the limiter or divertor plates, the energy carried per particle to the walls, and the effective flux limit. The self-consistent electrostatic potential in the quasi-neutral scrape-off layer is determined by using the ion kinetic model of the layer along with a Maxwell-Boltzmann electron response that occurs because most electrons are reflected by the Debye sheaths (assumed to be infinitely thin) at the limiter or divertor plates

  2. Magnetic field line random walk in two-dimensional dynamical turbulence

    Science.gov (United States)

    Wang, J. F.; Qin, G.; Ma, Q. M.; Song, T.; Yuan, S. B.

    2017-08-01

    The field line random walk (FLRW) of magnetic turbulence is one of the important topics in plasma physics and astrophysics. In this article, by using the field line tracing method, the mean square displacement (MSD) of FLRW is calculated on all possible length scales for pure two-dimensional turbulence with the damping dynamical model. We demonstrate that in order to describe FLRW with the damping dynamical model, a new dimensionless quantity R is needed to be introduced. On different length scales, dimensionless MSD shows different relationships with the dimensionless quantity R. Although the temporal effect affects the MSD of FLRW and even changes regimes of FLRW, it does not affect the relationship between the dimensionless MSD and dimensionless quantity R on all possible length scales.

  3. Discrete formulation for two-dimensional multigroup neutron diffusion equations

    Energy Technology Data Exchange (ETDEWEB)

    Vosoughi, Naser E-mail: vosoughi@mehr.sharif.edu; Salehi, Ali A.; Shahriari, Majid

    2003-02-01

    The objective of this paper is to introduce a new numerical method for neutronic calculation in a reactor core. This method can produce the final finite form of the neutron diffusion equation by classifying the neutronic variables and using two kinds of cell complexes without starting from the conventional differential form of the neutron diffusion equation. The method with linear interpolation produces the same convergence as the linear continuous finite element method. The quadratic interpolation is proven; the convergence order depends on the shape of the dual cell. The maximum convergence order is achieved by choosing the dual cell based on two Gauss' points. The accuracy of the method was examined with a well-known IAEA two-dimensional benchmark problem. The numerical results demonstrate the effectiveness of the new method.

  4. Discrete formulation for two-dimensional multigroup neutron diffusion equations

    International Nuclear Information System (INIS)

    Vosoughi, Naser; Salehi, Ali A.; Shahriari, Majid

    2003-01-01

    The objective of this paper is to introduce a new numerical method for neutronic calculation in a reactor core. This method can produce the final finite form of the neutron diffusion equation by classifying the neutronic variables and using two kinds of cell complexes without starting from the conventional differential form of the neutron diffusion equation. The method with linear interpolation produces the same convergence as the linear continuous finite element method. The quadratic interpolation is proven; the convergence order depends on the shape of the dual cell. The maximum convergence order is achieved by choosing the dual cell based on two Gauss' points. The accuracy of the method was examined with a well-known IAEA two-dimensional benchmark problem. The numerical results demonstrate the effectiveness of the new method

  5. A proposal of Fourier-Bessel expansion with optimized ensembles of bases to analyse two dimensional image

    Science.gov (United States)

    Yamasaki, K.; Fujisawa, A.; Nagashima, Y.

    2017-09-01

    It is a critical issue to find the best set of fitting function bases in mode structural analysis of two dimensional images like plasma emission profiles. The paper proposes a method to optimize a set of the bases in the case of Fourier-Bessel function series, using their orthonormal property, for more efficient and precise analysis. The method is applied on a tomography image of plasma emission obtained with the Maximum-likelihood expectation maximization method in a linear cylindrical device. The result demonstrates the excellency of the method that realizes the smaller residual error and minimum Akaike information criterion using smaller number of fitting function bases.

  6. Study on the Reflection Spectra of One Dimensional Plasma Photonic Crystals Having Exponentially Graded Materials

    International Nuclear Information System (INIS)

    Prasad, S.; Singh, Vivek; Singh, A. K.

    2013-01-01

    The transfer matrix method is used to study the effect of the permittivity profile on the reflectivity of a one dimensional plasma photonic crystal having exponentially graded material. The analysis shows that the proposed structure works as a perfect mirror within a certain frequency range. These frequency ranges can be completely controlled by the permittivity profile of a graded dielectric layer. As expected we observed that these frequency ranges are also controlled by plasma parameters. (plasma technology)

  7. Two-dimensional liquid chromatography

    DEFF Research Database (Denmark)

    Græsbøll, Rune

    -dimensional separation space. Optimization of gradients in online RP×RP is more difficult than in normal HPLC as a result of the increased number of parameters and their influence on each other. Modeling the coverage of the compounds across the two-dimensional chromatogram as a result of a change in gradients could...... be used for optimization purposes, and reduce the time spend on optimization. In this thesis (chapter 6), and manuscript B, a measure of the coverage of the compounds in the twodimensional separation space is defined. It is then shown that this measure can be modeled for changes in the gradient in both...

  8. Hofstadter's butterfly in a two-dimensional lattice consisting of two sublattices

    Energy Technology Data Exchange (ETDEWEB)

    Vugalter, G A; Pastukhov, A S [Department of Physics, Nizhny Novgorod State University, 23 Gagarin Avenue, Nizhny Novgorod 603950 (Russian Federation)

    2004-06-04

    Harper's equations for simple and complex two-dimensional lattices subject to a magnetic field have been derived in the tight-binding approximation. In our derivation we do not neglect the influence of the magnetic field on the electron eigenfunctions and eigenvalues in isolated atoms. Using a variational procedure for finding eigenfunctions and eigenvalues, we have self-consistently obtained Hofstadter's butterflies. Even for a simple square lattice Hofstadter's butterfly differs from the butterfly obtained in the case in which the influence of the magnetic field on the electron eigenvalues and eigenfunctions in isolated atoms is not taken into account.

  9. Two-dimensional PIC simulations of ion beam instabilities in Supernova-driven plasma flows

    Energy Technology Data Exchange (ETDEWEB)

    Dieckmann, M E; Shukla, P K [Institut fuer Theoretische Physik IV, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany); Meli, A; Mastichiadis, A [Department of Physics, National University of Athens, Panepistimiopolis, Zografos 15783 (Greece); Drury, L O C [Dublin Institute for Advanced Studies, Dublin 2 (Ireland)], E-mail: markd@tp4.rub.de

    2008-06-15

    Supernova remnant blast shells can reach the flow speed v{sub s} = 0.1c and shocks form at its front. Instabilities driven by shock-reflected ion beams heat the plasma in the foreshock, which may inject particles into diffusive acceleration. The ion beams can have the speed v{sub b} {approx} v{sub s}. For v{sub b} << v{sub s} the Buneman or upper-hybrid instabilities dominate, while for v{sub b} >> v{sub s} the filamentation and mixed modes grow faster. Here the relevant waves for v{sub b} {approx} v{sub s} are examined and how they interact nonlinearly with the particles. The collision of two plasma clouds at the speed v{sub s} is modelled with particle-in-cell simulations, which convect with them magnetic fields oriented perpendicular to their flow velocity vector. One simulation models equally dense clouds and the other one uses a density ratio of 2. Both simulations show upper-hybrid waves that are planar over large spatial intervals and that accelerate electrons to {approx}10 keV. The symmetric collision yields only short oscillatory wave pulses, while the asymmetric collision also produces large-scale electric fields, probably through a magnetic pressure gradient. The large-scale fields destroy the electron phase space holes and they accelerate the ions, which facilitates the formation of a precursor shock.

  10. Focusing and non-focusing modulation strategies for the improvement of on-line two-dimensional hydrophilic interaction chromatography × reversed phase profiling of complex food samples.

    Science.gov (United States)

    Montero, Lidia; Ibáñez, Elena; Russo, Mariateresa; Rastrelli, Luca; Cifuentes, Alejandro; Herrero, Miguel

    2017-09-08

    Comprehensive two-dimensional liquid chromatography (LC × LC) is ever gaining interest in food analysis, as often, food-related samples are too complex to be analyzed through one-dimensional approaches. The use of hydrophilic interaction chromatography (HILIC) combined with reversed phase (RP) separations has already been demonstrated as a very orthogonal combination, which allows attaining increased resolving power. However, this coupling encompasses different analytical challenges, mainly related to the important solvent strength mismatch between the two dimensions, besides those common to every LC × LC method. In the present contribution, different strategies are proposed and compared to further increase HILIC × RP method performance for the analysis of complex food samples, using licorice as a model sample. The influence of different parameters in non-focusing modulation methods based on sampling loops, as well as under focusing modulation, through the use of trapping columns in the interface and through active modulation procedures are studied in order to produce resolving power and sensitivity gains. Although the use of a dilution strategy using sampling loops as well as the highest possible first dimension sampling rate allowed significant improvements on resolution, focusing modulation produced significant gains also in peak capacity and sensitivity. Overall, the obtained results demonstrate the great applicability and potential that active modulation may have for the analysis of complex food samples, such as licorice, by HILIC × RP. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Plasma non-uniformity in a symmetric radiofrequency capacitively-coupled reactor with dielectric side-wall: a two dimensional particle-in-cell/Monte Carlo collision simulation

    Science.gov (United States)

    Liu, Yue; Booth, Jean-Paul; Chabert, Pascal

    2018-02-01

    A Cartesian-coordinate two-dimensional electrostatic particle-in-cell/Monte Carlo collision (PIC/MCC) plasma simulation code is presented, including a new treatment of charge balance at dielectric boundaries. It is used to simulate an Ar plasma in a symmetric radiofrequency capacitively-coupled parallel-plate reactor with a thick (3.5 cm) dielectric side-wall. The reactor size (12 cm electrode width, 2.5 cm electrode spacing) and frequency (15 MHz) are such that electromagnetic effects can be ignored. The dielectric side-wall effectively shields the plasma from the enhanced electric field at the powered-grounded electrode junction, which has previously been shown to produce locally enhanced plasma density (Dalvie et al 1993 Appl. Phys. Lett. 62 3207-9 Overzet and Hopkins 1993 Appl. Phys. Lett. 63 2484-6 Boeuf and Pitchford 1995 Phys. Rev. E 51 1376-90). Nevertheless, enhanced electron heating is observed in a region adjacent to the dielectric boundary, leading to maxima in ionization rate, plasma density and ion flux to the electrodes in this region, and not at the reactor centre as would otherwise be expected. The axially-integrated electron power deposition peaks closer to the dielectric edge than the electron density. The electron heating components are derived from the PIC/MCC simulations and show that this enhanced electron heating results from increased Ohmic heating in the axial direction as the electron density decreases towards the side-wall. We investigated the validity of different analytical formulas to estimate the Ohmic heating by comparing them to the PIC results. The widespread assumption that a time-averaged momentum transfer frequency, v m , can be used to estimate the momentum change can cause large errors, since it neglects both phase and amplitude information. Furthermore, the classical relationship between the total electron current and the electric field must be used with caution, particularly close to the dielectric edge where the (neglected

  12. Characterization of energy flow and instability development in two-dimensional simulations of hollow z pinches

    International Nuclear Information System (INIS)

    Peterson, D.L.; Bowers, R.L.; McLenithan, K.D.; Deeney, C.; Chandler, G.A.; Spielman, R.B.; Matzen, M.K.; Roderick, N.F.

    1998-01-01

    A two-dimensional (2-D) Eulerian Radiation-Magnetohydrodynamic (RMHD) code has been used to simulate imploding z pinches for three experiments fielded on the Los Alamos Pegasus II capacitor bank [J. C. Cochrane et al., Dense Z-Pinches, Third International Conference, London, United Kingdom 1993 (American Institute of Physics, New York, 1994), p. 381] and the Sandia Saturn accelerator [R. B. Spielman et al., Dense Z-Pinches, Second International Conference, Laguna Beach, 1989 (American Institute of Physics, New York, 1989), p. 3] and Z accelerator [R. B. Spielman et al., Phys. Plasmas 5, 2105 (1998)]. These simulations match the experimental results closely and illustrate how the code results may be used to track the flow of energy in the simulation and account for the amount of total radiated energy. The differences between the calculated radiated energy and power in 2-D simulations and those from zero-dimensional (0-D) and one-dimensional (1-D) Lagrangian simulations (which typically underpredict the total radiated energy and overpredict power) are due to the radially extended nature of the plasma shell, an effect which arises from the presence of magnetically driven Rayleigh endash Taylor instabilities. The magnetic Rayleigh endash Taylor instabilities differ substantially from hydrodynamically driven instabilities and typical measures of instability development such as e-folding times and mixing layer thickness are inapplicable or of limited value. A new measure of global instability development is introduced, tied to the imploding plasma mass, termed open-quotes fractional involved mass.close quotes Examples of this quantity are shown for the three experiments along with a discussion of the applicability of this measure. copyright 1998 American Institute of Physics

  13. Application of a method for comparing one-dimensional and two-dimensional models of a ground-water flow system

    International Nuclear Information System (INIS)

    Naymik, T.G.

    1978-01-01

    To evaluate the inability of a one-dimensional ground-water model to interact continuously with surrounding hydraulic head gradients, simulations using one-dimensional and two-dimensional ground-water flow models were compared. This approach used two types of models: flow-conserving one-and-two dimensional models, and one-dimensional and two-dimensional models designed to yield two-dimensional solutions. The hydraulic conductivities of controlling features were varied and model comparison was based on the travel times of marker particles. The solutions within each of the two model types compare reasonably well, but a three-dimensional solution is required to quantify the comparison

  14. Two-dimensional analytic weighting functions for limb scattering

    Science.gov (United States)

    Zawada, D. J.; Bourassa, A. E.; Degenstein, D. A.

    2017-10-01

    Through the inversion of limb scatter measurements it is possible to obtain vertical profiles of trace species in the atmosphere. Many of these inversion methods require what is often referred to as weighting functions, or derivatives of the radiance with respect to concentrations of trace species in the atmosphere. Several radiative transfer models have implemented analytic methods to calculate weighting functions, alleviating the computational burden of traditional numerical perturbation methods. Here we describe the implementation of analytic two-dimensional weighting functions, where derivatives are calculated relative to atmospheric constituents in a two-dimensional grid of altitude and angle along the line of sight direction, in the SASKTRAN-HR radiative transfer model. Two-dimensional weighting functions are required for two-dimensional inversions of limb scatter measurements. Examples are presented where the analytic two-dimensional weighting functions are calculated with an underlying one-dimensional atmosphere. It is shown that the analytic weighting functions are more accurate than ones calculated with a single scatter approximation, and are orders of magnitude faster than a typical perturbation method. Evidence is presented that weighting functions for stratospheric aerosols calculated under a single scatter approximation may not be suitable for use in retrieval algorithms under solar backscatter conditions.

  15. Soft plasma electrolysis with complex ions for optimizing electrochemical performance

    Science.gov (United States)

    Kamil, Muhammad Prisla; Kaseem, Mosab; Ko, Young Gun

    2017-03-01

    Plasma electrolytic oxidation (PEO) was a promising surface treatment for light metals to tailor an oxide layer with excellent properties. However, porous coating structure was generally exhibited due to excessive plasma discharges, restraining its performance. The present work utilized ethylenediaminetetraacetic acid (EDTA) and Cu-EDTA complexing agents as electrolyte additives that alter the plasma discharges to improve the electrochemical properties of Al-1.1Mg alloy coated by PEO. To achieve this purpose, PEO coatings were fabricated under an alternating current in silicate electrolytes containing EDTA and Cu-EDTA. EDTA complexes were found to modify the plasma discharging behaviour during PEO that led to a lower porosity than that without additives. This was attributed to a more homogeneous electrical field throughout the PEO process while the coating growth would be maintained by an excess of dissolved Al due to the EDTA complexes. When Cu-EDTA was used, the number of discharge channels in the coating layer was lower than that with EDTA due to the incorporation of Cu2O and CuO altering the dielectric behaviour. Accordingly, the sample in the electrolyte containing Cu-EDTA constituted superior corrosion resistance to that with EDTA. The electrochemical mechanism for excellent corrosion protection was elucidated in the context of equivalent circuit model.

  16. Vapour-liquid equilibrium properties for two- and three-dimensional Lennard-Jones fluids from equations of state

    International Nuclear Information System (INIS)

    Mulero, A.; Cuadros, F; Faundez, C.A.

    1999-01-01

    Vapour-liquid equilibrium properties for both three- and two-dimensional Lennard-Jones fluids were obtained using simple cubic-in-density equations of state proposed by the authors. Results were compared with those obtained by other workers from computer simulations and also with results given by other more complex semi-theoretical or semi-empirical equations of state. In the three-dimensional case good agreement is found for all properties and all temperatures. In the two-dimensional case only the coexistence densities were compared, producing good agreement for low temperatures only. The present work is the first to give numerical data for the vapour-liquid equilibrium properties of Lennard-Jones fluids calculated from equations of state. Copyright (1999) CSIRO Australia

  17. Structure of Langmuir and electromagnetic collapsing wave packets in two-dimensional strong plasma turbulence

    International Nuclear Information System (INIS)

    Alinejad, H.; Robinson, P. A.; Cairns, I. H.; Skjaeraasen, O.; Sobhanian, S.

    2007-01-01

    Nucleating and collapsing wave packets relevant to electromagnetic strong plasma turbulence are studied theoretically in two dimensions. Model collapsing Langmuir and transverse potentials are constructed as superpositions of approximate eigenstates of a spherically symmetric density well. Electrostatic and electromagnetic potentials containing only components with azimuthal quantum numbers m=0, 1, 2 are found to give a good representation of the electric fields of nucleating collapsing wave packets in turbulence simulations. The length scales of these trapped states are related to the electron thermal speed v e and the length scale of the density well. It is shown analytically that the electromagnetic trapped states change with v e and that for v e e > or approx. 0.17c, the Langmuir and transverse modes remain coupled during collapse, with autocorrelation lengths in a constant ratio. An investigation of energy transfer to packets localized in density wells shows that the strongest power transfer to the nucleating state occurs for Langmuir waves. Energy transitions between different trapped and free states for collapsing wave packets are studied, and the transition rate from trapped Langmuir to free plane electromagnetic waves is calculated and related to the emission of electromagnetic waves at the plasma frequency

  18. DEVELOPMENT OF COMPLEX EQUIPMENT FOR PLASMA SPRAY CERAMIC COATINGS

    Directory of Open Access Journals (Sweden)

    V. V. Okovity

    2017-01-01

    Full Text Available Develop a set equipment for plasma forming ceramic coatings. The article presents characteristics and parameters of the developed complex equipment for formation of plasma ceramic coatings as well as results of its testing. Methods of research is based on studies of structural elements composite plasma coatings system ZrO2 – Y2O3  obtained  using  developed complex equipment. One of the most effective ways to protect the components from high temperature corrosion and oxidation is formation on the surface of plasma thermal barrier coatings. For thermal barrier coating has very strict requirements: сharacterized by a smooth change of physico-mechanical properties (porosity, microhardness, elastic modulus in the cross section of the metal substrate to the outer ceramic layer; to withstand multiple cycles of thermal cycling from room temperature to the operating temperature; to maintain gastightness under operating conditions and thus ensure a sufficiently high level of adhesive strength. For realization of new technological schemes applying thermal barrier coatings with high operational characteristics was developed, patented and manufactured a range of new equipment. The experiments show that authors developed PBG-1 plasmatron and powder feeder PPBG-04 have at least 2–3 times the service life during the deposition of ceramic materials compared to the standard equipment of the company "Plasma-Technik", by changing the structure of the cathode-anode plasma torch assembly and construction of the delivery unit of the feeder to facilitate the uniform supply of the powder into the plasma jet and the best of his penetration. The result is better plasma coatings with improved operational characteristics: adhesion strength is increased to 1.3–2 times, material utilization in 1.5–1.6 times microhardness 1.2–1.4 times the porosity is reduced by 2–2.5 times.

  19. Depth-enhanced three-dimensional-two-dimensional convertible display based on modified integral imaging.

    Science.gov (United States)

    Park, Jae-Hyeung; Kim, Hak-Rin; Kim, Yunhee; Kim, Joohwan; Hong, Jisoo; Lee, Sin-Doo; Lee, Byoungho

    2004-12-01

    A depth-enhanced three-dimensional-two-dimensional convertible display that uses a polymer-dispersed liquid crystal based on the principle of integral imaging is proposed. In the proposed method, a lens array is located behind a transmission-type display panel to form an array of point-light sources, and a polymer-dispersed liquid crystal is electrically controlled to pass or to scatter light coming from these point-light sources. Therefore, three-dimensional-two-dimensional conversion is accomplished electrically without any mechanical movement. Moreover, the nonimaging structure of the proposed method increases the expressible depth range considerably. We explain the method of operation and present experimental results.

  20. CFD three dimensional wake analysis in complex terrain

    Science.gov (United States)

    Castellani, F.; Astolfi, D.; Terzi, L.

    2017-11-01

    Even if wind energy technology is nowadays fully developed, the use of wind energy in very complex terrain is still challenging. In particular, it is challenging to characterize the combination effects of wind ow over complex terrain and wake interactions between nearby turbines and this has a practical relevance too, for the perspective of mitigating anomalous vibrations and loads as well improving the farm efficiency. In this work, a very complex terrain site has been analyzed through a Reynolds-averaged CFD (Computational Fluid Dynamics) numerical wind field model; in the simulation the inuence of wakes has been included through the Actuator Disk (AD) approach. In particular, the upstream turbine of a cluster of 4 wind turbines having 2.3 MW of rated power is studied. The objective of this study is investigating the full three-dimensional wind field and the impact of three-dimensionality on the evolution of the waked area between nearby turbines. A post-processing method of the output of the CFD simulation is developed and this allows to estimate the wake lateral deviation and the wake width. The reliability of the numerical approach is inspired by and crosschecked through the analysis of the operational SCADA (Supervisory Control and Data Acquisition) data of the cluster of interest.

  1. Observation of electron plasma waves in plasma of two-temperature electrons

    International Nuclear Information System (INIS)

    Ikezawa, Shunjiro; Nakamura, Yoshiharu.

    1981-01-01

    Propagation of electron plasma waves in a large and unmagnetized plasma containing two Maxwellian distributions of electrons is studied experimentally. Two kinds of plasma sources which supply electrons of different temperature are used. The temperature ratio is about 3 and the density ratio of hot to cool electrons is varied from 0 to 0.5. A small contamination of hot electrons enhances the Landau damping of the principal mode known as the Bohm-Gross mode. When the density of hot electrons is larger than about 0.2, two modes are observed. The results agree with theoretical dispersion relations when excitation efficiencies of the modes are considered. (author)

  2. Thermal structure of the ionosphere of Mars - simulations with one- and two-dimensional models

    International Nuclear Information System (INIS)

    Singhal, R.P.; Whitten, R.C.

    1988-01-01

    Heat flux saturation effects are included in the present one- and two-dimensional models of the Martian upper ionosphere's thermal structure. The inclusion of small upper boundary and volume heat sources is found to yield satisfactory simulations of the dayside ion temperature observation results obtained by Viking 1's retarding potential analyzers. It is noted that the plasma flow-transport of heat from the dayside to the nightside makes no contribution to the ion and electron temperatures that have been calculated for the nightside. 22 references

  3. Simulation of plasma double-layer structures

    International Nuclear Information System (INIS)

    Borovsky, J.E.; Joyce, G.

    1982-01-01

    Electrostatic plasma double layers are numerically simulated by means of a magnetized 2 1/2-dimensional particle-in-cell method. The investigation of planar double layers indicates that these one-dimensional potential structures are susceptible to periodic disruption by instabilities in the low-potential plasmas. Only a slight increase in the double-layer thickness with an increase in its obliqueness to the magnetic field is observed. Weak magnetization results in the double-layer electric-field alignment of accelerated particles and strong magnetization results in their magnetic-field alignment. The numerial 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. Electron-beam excited electrostatic electron-cyclotron waves and (ion-beam driven) solitary waves are present in the plasmas adjacent to the double layers

  4. Functional inks and printing of two-dimensional materials.

    Science.gov (United States)

    Hu, Guohua; Kang, Joohoon; Ng, Leonard W T; Zhu, Xiaoxi; Howe, Richard C T; Jones, Christopher G; Hersam, Mark C; Hasan, Tawfique

    2018-05-08

    Graphene and related two-dimensional materials provide an ideal platform for next generation disruptive technologies and applications. Exploiting these solution-processed two-dimensional materials in printing can accelerate this development by allowing additive patterning on both rigid and conformable substrates for flexible device design and large-scale, high-speed, cost-effective manufacturing. In this review, we summarise the current progress on ink formulation of two-dimensional materials and the printable applications enabled by them. We also present our perspectives on their research and technological future prospects.

  5. A two-dimensional hydrogen-bonded water layer in the structure of a cobalt(III) cubane complex.

    Science.gov (United States)

    Qi, Ji; Zhai, Xiang-Sheng; Zhu, Hong-Lin; Lin, Jian-Li

    2014-02-01

    A tetranuclear Co(III) oxide complex with cubane topology, tetrakis(2,2'-bipyridine-κ(2)N,N')di-μ2-carbonato-κ(4)O:O'-tetra-μ3-oxido-tetracobalt(III) pentadecahydrate, [Co4(CO3)2O4(C10H8N2)4]·15H2O, with an unbounded hydrogen-bonded water layer, has been synthesized by reaction of CoCO3 and 2,2'-bipyridine. The solvent water molecules form a hydrogen-bonded net with tetrameric and pentameric water clusters as subunits. The Co4O4 cubane-like cores are sandwiched between the water layers, which are further stacked into a three-dimensional metallo-supramolecular network.

  6. K-FIX: a computer program for transient, two-dimensional, two-fluid flow. THREED: an extension of the K-FIX code for three-dimensional calculations

    International Nuclear Information System (INIS)

    Rivard, W.C.; Torrey, M.D.

    1978-10-01

    The transient, two-dimensional, two-fluid code K-FIX has been extended to perform three-dimensional calculations. This capability is achieved by adding five modification sets of FORTRAN statements to the basic two-dimensional code. The modifications are listed and described, and a complete listing of the three-dimensional code is provided. Results of an example problem are provided for verification

  7. Benchmark numerical solutions for radiative heat transfer in two-dimensional medium with graded index distribution

    Energy Technology Data Exchange (ETDEWEB)

    Liu, L.H. [School of Energy Science and Engineering, Harbin Institute of Technology, 92 West Dazhi Street, Harbin 150001 (China)]. E-mail: lhliu@hit.edu.cn

    2006-11-15

    In graded index media, the ray goes along a curved path determined by Fermat principle. Generally, the curved ray trajectory in graded index media is a complex implicit function, and the curved ray tracing is very difficult and complex. Only for some special refractive index distributions, the curved ray trajectory can be expressed as a simple explicit function. Two important examples are the layered and the radial graded index distributions. In this paper, the radiative heat transfer problems in two-dimensional square semitransparent with layered and radial graded index distributions are analyzed. After deduction of the ray trajectory, the radiative heat transfer problems are solved by using the Monte Carlo curved ray-tracing method. Some numerical solutions of dimensionless net radiative heat flux and medium temperature are tabulated as the benchmark solutions for the future development of approximation techniques for multi-dimensional radiative heat transfer in graded index media.

  8. Two-dimensional charge transport in self-organized, high-mobility conjugated polymers

    DEFF Research Database (Denmark)

    Sirringhaus, H.; Brown, P.J.; Friend, R.H.

    1999-01-01

    Self-organization in many solution-processed, semiconducting conjugated polymers results in complex microstructures, in which ordered microcrystalline domains are embedded in an amorphous matrix(I). This has important consequences for electrical properties of these materials: charge transport...... of the ordered microcrystalline domains in the conjugated polymer poly(3-hexylthiophene), P3HT, Self-organization in P3HT results in a lamella structure with two-dimensional conjugated sheets formed by interchain stacking. We find that, depending on processing conditions, the lamellae can adopt two different...... of polymer transistors in logic circuits(5) and active-matrix displays(4,6)....

  9. Three dimensional simulation study of spheromak injection into magnetized plasmas

    International Nuclear Information System (INIS)

    Suzuki, Y.; Watanabe, T.H.; Sato, T.; Hayashi, T.

    2000-01-01

    The three dimensional dynamics of a spheromak-like compact toroid (SCT) plasmoid, which is injected into a magnetized target plasma region, is investigated by using MHD numerical simulations. It is found that the process of SCT penetration into this region is much more complicated than that which has been analysed so far by using a conducting sphere (CS) model. The injected SCT suffers from a tilting instability, which grows with a similar timescale to that of the SCT penetration. The instability is accompanied by magnetic reconnection between the SCT magnetic field and the target magnetic field, which disrupts the magnetic configuration of the SCT. Magnetic reconnection plays a role in supplying the high density plasma, initially confined in the SCT magnetic field, to the target region. The penetration depth of the SCT high density plasma is also examined. It is shown to be shorter than that estimated from the CS model. The SCT high density plasma is decelerated mainly by the Lorentz force of the target magnetic field, which includes not only the magnetic pressure force but also the magnetic tension force. Furthermore, by comparing the SCT plasmoid injection with the bare plasmoid injection, magnetic reconnection is considered to relax the magnetic tension force, i.e. the deceleration of the SCT plasmoid. (author)

  10. Two-dimensional critical phenomena

    International Nuclear Information System (INIS)

    Saleur, H.

    1987-09-01

    Two dimensional critical systems are studied using transformation to free fields and conformal invariance methods. The relations between the two approaches are also studied. The analytical results obtained generally depend on universality hypotheses or on renormalization group trajectories which are not established rigorously, so numerical verifications, mainly using the transfer matrix approach, are presented. The exact determination of critical exponents; the partition functions of critical models on toruses; and results as the critical point is approached are discussed [fr

  11. Light propagation in one-dimensional porous silicon complex systems

    NARCIS (Netherlands)

    Oton, C.J.; Dal Negro, L.; Gaburro, Z.; Pavesi, L.; Johnson, P.J.; Lagendijk, Aart; Wiersma, D.S.

    2003-01-01

    We discuss the optical properties of one-dimensional complex dielectric systems, in particular the time-resolved transmission through thick porous silicon quasiperiodic multi-layers. Both in numerical calculations and experiments we find dramatic distortion effects, i.e. pulse stretching and

  12. Almost two-dimensional treatment of drift wave turbulence

    International Nuclear Information System (INIS)

    Albert, J.M.; Similon, P.L.; Sudan, R.N.

    1990-01-01

    The approximation of two-dimensionality is studied and extended for electrostatic drift wave turbulence in a three-dimensional, magnetized plasma. It is argued on the basis of the direct interaction approximation that in the absence of parallel viscosity, purely 2-D solutions exist for which only modes with k parallel =0 are excited, but that the 2-D spectrum is unstable to perturbations at nonzero k parallel . A 1-D equation for the parallel profile g k perpendicular (k parallel ) of the saturated spectrum at steady state is derived and solved, allowing for parallel viscosity; the spectrum has finite width in k parallel , and hence finite parallel correlation length, as a result of nonlinear coupling. The enhanced energy dissipation rate, a 3-D effect, may be incorporated in the 2-D approximation by a suitable renormalization of the linear dissipation term. An algorithm is presented that reduces the 3-D problem to coupled 1- and 2-D problems. Numerical results from a 2-D spectral direct simulation, thus modified, are compared with the results from the corresponding 3-D (unmodified) simulation for a specific model of drift wave excitation. Damping at high k parallel is included. It is verified that the 1-D solution for g k perpendicular (k parallel ) accurately describes the shape and width of the 3-D spectrum, and that the modified 2-D simulation gives a good estimate of the 3-D energy saturation level and distribution E(k perpendicular )

  13. Theoretical models of non-Maxwellian equilibria for one-dimensional collisionless plasmas

    Science.gov (United States)

    Allanson, O.; Neukirch, T.; Wilson, F.; Troscheit, S.

    2016-12-01

    It is ideal to use exact equilibrium solutions of the steady state Vlasov-Maxwell system to intialise collsionless simulations. However, exact equilibrium distribution functions (DFs) for a given macroscopic configuration are typically unknown, and it is common to resort to using `flow-shifted' Maxwellian DFs in their stead. These DFs may be consistent with a macrosopic system with the target number density and current density, but could well have inaccurate higher order moments. We present recent theoretical work on the `inverse problem in Vlasov-Maxwell equilibria', namely calculating an exact solution of the Vlasov equation for a specific given magnetic field. In particular, we focus on one-dimensional geometries in Cartesian (current sheets) coordinates.1. From 1D fields to Vlasov equilibria: Theory and application of Hermite Polynomials: (O. Allanson, T. Neukirch, S. Troscheit and F. Wilson, Journal of Plasma Physics, 82, 905820306 (2016) [28 pages, Open Access] )2. An exact collisionless equilibrium for the Force-Free Harris Sheet with low plasma beta: (O. Allanson, T. Neukirch, F. Wilson and S. Troscheit, Physics of Plasmas, 22, 102116 (2015) [11 pages, Open Access])3. Neutral and non-neutral collisionless plasma equilibria for twisted flux tubes: The Gold-Hoyle model in a background field (O. Allanson, F. Wilson and T. Neukirch, (2016)) (accepted, Physics of Plasmas)

  14. Application of Steenbeck's minimum principle for three-dimensional modelling of DC arc plasma torches

    International Nuclear Information System (INIS)

    Li Heping; Pfender, E; Chen, Xi

    2003-01-01

    In this paper, physical/mathematical models for the three-dimensional, quasi-steady modelling of the plasma flow and heat transfer inside a non-transferred DC arc plasma torch are described in detail. The Steenbeck's minimum principle (Finkelnburg W and Maecker H 1956 Electric arcs and thermal plasmas Encyclopedia of Physics vol XXII (Berlin: Springer)) is employed to determine the axial position of the anode arc-root at the anode surface. This principle postulates a minimum arc voltage for a given arc current, working gas flow rate, and torch configuration. The modelling results show that the temperature and flow fields inside the DC non-transferred arc plasma torch show significant three-dimensional features. The predicted anode arc-root attachment position and the arc shape by employing Steenbeck's minimum principle are reasonably consistent with experimental observations. The thermal efficiency and the torch power distribution are also calculated in this paper. The results show that the thermal efficiency of the torch always ranges from 30% to 45%, i.e. more than half of the total power input is taken away by the cathode and anode cooling water. The special heat transfer mechanisms at the plasma-anode interface, such as electron condensation, electron enthalpy and radiative heat transfer from the bulk plasma to the anode inner surface, are taken into account in this paper. The calculated results show that besides convective heat transfer, the contributions of electron condensation, electron enthalpy and radiation to the anode heat transfer are also important (∼30% for parameter range of interest in this paper). Additional effects, such as the non-local thermodynamic equilibrium plasma state near the electrodes, the transient phenomena, etc, need to be considered in future physical/mathematical models, including corresponding measurements

  15. Two-dimensional capillary origami

    Energy Technology Data Exchange (ETDEWEB)

    Brubaker, N.D., E-mail: nbrubaker@math.arizona.edu; Lega, J., E-mail: lega@math.arizona.edu

    2016-01-08

    We describe a global approach to the problem of capillary origami that captures all unfolded equilibrium configurations in the two-dimensional setting where the drop is not required to fully wet the flexible plate. We provide bifurcation diagrams showing the level of encapsulation of each equilibrium configuration as a function of the volume of liquid that it contains, as well as plots representing the energy of each equilibrium branch. These diagrams indicate at what volume level the liquid drop ceases to be attached to the endpoints of the plate, which depends on the value of the contact angle. As in the case of pinned contact points, three different parameter regimes are identified, one of which predicts instantaneous encapsulation for small initial volumes of liquid. - Highlights: • Full solution set of the two-dimensional capillary origami problem. • Fluid does not necessarily wet the entire plate. • Global energy approach provides exact differential equations satisfied by minimizers. • Bifurcation diagrams highlight three different regimes. • Conditions for spontaneous encapsulation are identified.

  16. Two-dimensional capillary origami

    International Nuclear Information System (INIS)

    Brubaker, N.D.; Lega, J.

    2016-01-01

    We describe a global approach to the problem of capillary origami that captures all unfolded equilibrium configurations in the two-dimensional setting where the drop is not required to fully wet the flexible plate. We provide bifurcation diagrams showing the level of encapsulation of each equilibrium configuration as a function of the volume of liquid that it contains, as well as plots representing the energy of each equilibrium branch. These diagrams indicate at what volume level the liquid drop ceases to be attached to the endpoints of the plate, which depends on the value of the contact angle. As in the case of pinned contact points, three different parameter regimes are identified, one of which predicts instantaneous encapsulation for small initial volumes of liquid. - Highlights: • Full solution set of the two-dimensional capillary origami problem. • Fluid does not necessarily wet the entire plate. • Global energy approach provides exact differential equations satisfied by minimizers. • Bifurcation diagrams highlight three different regimes. • Conditions for spontaneous encapsulation are identified.

  17. Matrix method for two-dimensional waveguide mode solution

    Science.gov (United States)

    Sun, Baoguang; Cai, Congzhong; Venkatesh, Balajee Seshasayee

    2018-05-01

    In this paper, we show that the transfer matrix theory of multilayer optics can be used to solve the modes of any two-dimensional (2D) waveguide for their effective indices and field distributions. A 2D waveguide, even composed of numerous layers, is essentially a multilayer stack and the transmission through the stack can be analysed using the transfer matrix theory. The result is a transfer matrix with four complex value elements, namely A, B, C and D. The effective index of a guided mode satisfies two conditions: (1) evanescent waves exist simultaneously in the first (cladding) layer and last (substrate) layer, and (2) the complex element D vanishes. For a given mode, the field distribution in the waveguide is the result of a 'folded' plane wave. In each layer, there is only propagation and absorption; at each boundary, only reflection and refraction occur, which can be calculated according to the Fresnel equations. As examples, we show that this method can be used to solve modes supported by the multilayer step-index dielectric waveguide, slot waveguide, gradient-index waveguide and various plasmonic waveguides. The results indicate the transfer matrix method is effective for 2D waveguide mode solution in general.

  18. Two-dimensional behavior of solitons in a low-β plasma with convective motion

    International Nuclear Information System (INIS)

    Makino, Mitsuhiro; Kamimura, Tetsuo; Sato, Tetsuya.

    1981-01-01

    The initial value problem of the Hasegawa-Mima (HM) equation, which describes the propagation of drift waves in a low beta magnetized plasma, is numerically studied. Solitons are formed from an initial sinusoidal wave. For a wide range of initial conditions, the number of solitons and the recurrence time agree well with those obtained from the KdV eq. reduced from the HM eq. by Nozaki et al. As a result of nonlinear interactions among different solitons, their peak positions shift in the direction normal to the zeroth order convective motion in a regular but different fashion. When we start from a sinusoidal wave, the peaks of the generated soliton train line up on a line at an angle with respect to the convective direction. Two-deimensional collisions of different solitons are examined. (author)

  19. Two-dimensional black holes and non-commutative spaces

    International Nuclear Information System (INIS)

    Sadeghi, J.

    2008-01-01

    We study the effects of non-commutative spaces on two-dimensional black hole. The event horizon of two-dimensional black hole is obtained in non-commutative space up to second order of perturbative calculations. A lower limit for the non-commutativity parameter is also obtained. The observer in that limit in contrast to commutative case see two horizon

  20. Entanglement entropy and complexity for one-dimensional holographic superconductors

    Science.gov (United States)

    Kord Zangeneh, Mahdi; Ong, Yen Chin; Wang, Bin

    2017-08-01

    Holographic superconductor is an important arena for holography, as it allows concrete calculations to further understand the dictionary between bulk physics and boundary physics. An important quantity of recent interest is the holographic complexity. Conflicting claims had been made in the literature concerning the behavior of holographic complexity during phase transition. We clarify this issue by performing a numerical study on one-dimensional holographic superconductor. Our investigation shows that holographic complexity does not behave in the same way as holographic entanglement entropy. Nevertheless, the universal terms of both quantities are finite and reflect the phase transition at the same critical temperature.

  1. Self-consistent one-dimensional modelling of x-ray laser plasmas

    International Nuclear Information System (INIS)

    Wan, A.S.; Walling, R.S.; Scott, H.A.; Mayle, R.W.; Osterheld, A.L.

    1992-01-01

    This paper presents the simulation of a planar, one-dimensional expanding Ge x-ray laser plasma using a new code which combines hydrodynamics, laser absorption, and detailed level population calculations within the same simulation. Previously, these simulations were performed in separate steps. We will present the effect of line transfer on gains and excited level populations and compare the line transfer result with simulations using escape probabilities. We will also discuss the impact of different atomic models on the accuracy of our simulation

  2. Two-dimensional Navier-Stokes turbulence in bounded domains

    NARCIS (Netherlands)

    Clercx, H.J.H.; van Heijst, G.J.F.

    In this review we will discuss recent experimental and numerical results of quasi-two-dimensional decaying and forced Navier–Stokes turbulence in bounded domains. We will give a concise overview of developments in two-dimensional turbulence research, with emphasis on the progress made during the

  3. Two-dimensional Navier-Stokes turbulence in bounded domains

    NARCIS (Netherlands)

    Clercx, H.J.H.; Heijst, van G.J.F.

    2009-01-01

    In this review we will discuss recent experimental and numerical results of quasi-two-dimensional decaying and forced Navier–Stokes turbulence in bounded domains. We will give a concise overview of developments in two-dimensional turbulence research, with emphasis on the progress made during the

  4. Agglomeration of microparticles in complex plasmas

    International Nuclear Information System (INIS)

    Du, Cheng-Ran; Thomas, Hubertus M.; Ivlev, Alexei V.; Konopka, Uwe; Morfill, Gregor E.

    2010-01-01

    Agglomeration of highly charged microparticles was observed and studied in complex plasma experiments carried out in a capacitively coupled rf discharge. The agglomeration was caused by strong waves triggered in a particle cloud by decreasing neutral gas pressure. Using a high-speed camera during this unstable regime, it was possible to resolve the motion of individual microparticles and to show that the relative velocities of some particles were sufficiently high to overcome the mutual Coulomb repulsion and hence to result in agglomeration. After stabilizing the cloud again through the increase of the pressure, we were able to observe the aggregates directly with a long-distance microscope. We show that the agglomeration rate deduced from our experiments is in good agreement with theoretical estimates. In addition, we briefly discuss the mechanisms that can provide binding of highly charged microparticles in a plasma.

  5. Piezoelectricity in Two-Dimensional Materials

    KAUST Repository

    Wu, Tao; Zhang, Hua

    2015-01-01

    Powering up 2D materials: Recent experimental studies confirmed the existence of piezoelectricity - the conversion of mechanical stress into electricity - in two-dimensional single-layer MoS2 nanosheets. The results represent a milestone towards

  6. Ion-streaming induced order transition in three-dimensional dust clusters

    International Nuclear Information System (INIS)

    Ludwig, Patrick; Kählert, Hanno; Bonitz, Michael

    2012-01-01

    Dust dynamics simulations utilizing a dynamical screening approach are performed to study the effect of ion-streaming on the self-organized structures in a three-dimensional spherically confined complex (dusty) plasma. Varying the Mach number M, the ratio of ion drift velocity to the sound velocity, the simulations reproduce the experimentally observed cluster configurations in the two limiting cases: at M = 0 strongly correlated crystalline structures consisting of nested spherical shells (Yukawa balls) and, for M ⩾ 1, flow-aligned dust chains, respectively. In addition, our simulations reveal a discontinuous transition between these two limits. It is found that already a moderate ion drift velocity (M ≈ 0.1 for the plasma conditions considered here) destabilizes the highly ordered Yukawa balls and initiates an abrupt melting transition. The critical value of M is found to be independent of the cluster size. (paper)

  7. Hall MHD Modeling of Two-dimensional Reconnection: Application to MRX Experiment

    International Nuclear Information System (INIS)

    Lukin, V.S.; Jardin, S.C.

    2003-01-01

    Two-dimensional resistive Hall magnetohydrodynamics (MHD) code is used to investigate the dynamical evolution of driven reconnection in the Magnetic Reconnection Experiment (MRX). The initial conditions and dimensionless parameters of the simulation are set to be similar to the experimental values. We successfully reproduce many features of the time evolution of magnetic configurations for both co- and counter-helicity reconnection in MRX. The Hall effect is shown to be important during the early dynamic X-phase of MRX reconnection, while effectively negligible during the late ''steady-state'' Y-phase, when plasma heating takes place. Based on simple symmetry considerations, an experiment to directly measure the Hall effect in MRX configuration is proposed and numerical evidence for the expected outcome is given

  8. Solution of the two-dimensional spectral factorization problem

    Science.gov (United States)

    Lawton, W. M.

    1985-01-01

    An approximation theorem is proven which solves a classic problem in two-dimensional (2-D) filter theory. The theorem shows that any continuous two-dimensional spectrum can be uniformly approximated by the squared modulus of a recursively stable finite trigonometric polynomial supported on a nonsymmetric half-plane.

  9. Feasibility study of the plasma electron density measurement by electromagnetic radiation from the laser-driven plasma wave

    International Nuclear Information System (INIS)

    Jang, D G; Kim, J J; Suk, H; Hur, M S

    2012-01-01

    When an intense laser beam is focused in a plasma, a plasma wake wave is generated and the oscillatary motion of the plasma electrons produces a strong electromagnetic wave by a Cherenkov-like process. Spectrum of the genetated electromagnetic wave has dependence on the plasma density. In this paper, we propose to use the emitted electromagnetic radiation for plasma diagnostic, which may provide an accurate information for local electron densities of the plasma and will be very useful for three-dimensional plasma density profiles by changing the focal point location of the laser beam. Two-dimensional (2-D) particle-in-cell (PIC) simulation is used to study the correlation between the spectrum of the emitted radiation and plasma density, and the results demonstrate that this method is promising for the electron density measurement in the plasma.

  10. GIS-based two-dimensional numerical simulation of rainfall-induced debris flow

    Directory of Open Access Journals (Sweden)

    C. Wang

    2008-02-01

    Full Text Available This paper aims to present a useful numerical method to simulate the propagation and deposition of debris flow across the three dimensional complex terrain. A depth-averaged two-dimensional numerical model is developed, in which the debris and water mixture is assumed to be continuous, incompressible, unsteady flow. The model is based on the continuity equations and Navier-Stokes equations. Raster grid networks of digital elevation model in GIS provide a uniform grid system to describe complex topography. As the raster grid can be used as the finite difference mesh, the continuity and momentum equations are solved numerically using the finite difference method. The numerical model is applied to simulate the rainfall-induced debris flow occurred in 20 July 2003, in Minamata City of southern Kyushu, Japan. The simulation reproduces the propagation and deposition and the results are in good agreement with the field investigation. The synthesis of numerical method and GIS makes possible the solution of debris flow over a realistic terrain, and can be used to estimate the flow range, and to define potentially hazardous areas for homes and road section.

  11. Design of efficient circularly symmetric two-dimensional variable digital FIR filters.

    Science.gov (United States)

    Bindima, Thayyil; Elias, Elizabeth

    2016-05-01

    Circularly symmetric two-dimensional (2D) finite impulse response (FIR) filters find extensive use in image and medical applications, especially for isotropic filtering. Moreover, the design and implementation of 2D digital filters with variable fractional delay and variable magnitude responses without redesigning the filter has become a crucial topic of interest due to its significance in low-cost applications. Recently the design using fixed word length coefficients has gained importance due to the replacement of multipliers by shifters and adders, which reduces the hardware complexity. Among the various approaches to 2D design, transforming a one-dimensional (1D) filter to 2D by transformation, is reported to be an efficient technique. In this paper, 1D variable digital filters (VDFs) with tunable cut-off frequencies are designed using Farrow structure based interpolation approach, and the sub-filter coefficients in the Farrow structure are made multiplier-less using canonic signed digit (CSD) representation. The resulting performance degradation in the filters is overcome by using artificial bee colony (ABC) optimization. Finally, the optimized 1D VDFs are mapped to 2D using generalized McClellan transformation resulting in low complexity, circularly symmetric 2D VDFs with real-time tunability.

  12. Development of Two-Dimensional NMR

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 20; Issue 11. Development of Two-Dimensional NMR: Strucure Determination of Biomolecules in Solution. Anil Kumar. General Article Volume 20 Issue 11 November 2015 pp 995-1002 ...

  13. ONE-DIMENSIONAL AND TWO-DIMENSIONAL LEADERSHIP STYLES

    OpenAIRE

    Nikola Stefanović

    2007-01-01

    In order to motivate their group members to perform certain tasks, leaders use different leadership styles. These styles are based on leaders' backgrounds, knowledge, values, experiences, and expectations. The one-dimensional styles, used by many world leaders, are autocratic and democratic styles. These styles lie on the two opposite sides of the leadership spectrum. In order to precisely define the leadership styles on the spectrum between the autocratic leadership style and the democratic ...

  14. Infrared magneto-spectroscopy of two-dimensional and three-dimensional massless fermions: A comparison

    Energy Technology Data Exchange (ETDEWEB)

    Orlita, M., E-mail: milan.orlita@lncmi.cnrs.fr [Laboratoire National des Champs Magnétiques Intenses, CNRS-UJF-UPS-INSA, 38042 Grenoble (France); Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 121 16 Prague 2 (Czech Republic); Faugeras, C.; Barra, A.-L.; Martinez, G.; Potemski, M. [Laboratoire National des Champs Magnétiques Intenses, CNRS-UJF-UPS-INSA, 38042 Grenoble (France); Basko, D. M. [LPMMC UMR 5493, Université Grenoble 1/CNRS, B.P. 166, 38042 Grenoble (France); Zholudev, M. S. [Laboratoire Charles Coulomb (L2C), UMR CNRS 5221, GIS-TERALAB, Université Montpellier II, 34095 Montpellier (France); Institute for Physics of Microstructures, RAS, Nizhny Novgorod GSP-105 603950 (Russian Federation); Teppe, F.; Knap, W. [Laboratoire Charles Coulomb (L2C), UMR CNRS 5221, GIS-TERALAB, Université Montpellier II, 34095 Montpellier (France); Gavrilenko, V. I. [Institute for Physics of Microstructures, RAS, Nizhny Novgorod GSP-105 603950 (Russian Federation); Mikhailov, N. N.; Dvoretskii, S. A. [A.V. Rzhanov Institute of Semiconductor Physics, Siberian Branch, Russian Academy of Sciences, Novosibirsk 630090 (Russian Federation); Neugebauer, P. [Institut für Physikalische Chemie, Universität Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart (Germany); Berger, C. [School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States); Institut Néel/CNRS-UJF BP 166, F-38042 Grenoble Cedex 9 (France); Heer, W. A. de [School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States)

    2015-03-21

    Here, we report on a magneto-optical study of two distinct systems hosting massless fermions—two-dimensional graphene and three-dimensional HgCdTe tuned to the zero band gap condition at the point of the semiconductor-to-semimetal topological transition. Both materials exhibit, in the quantum regime, a fairly rich magneto-optical response, which is composed from a series of intra- and interband inter-Landau level resonances with for massless fermions typical √(B) dependence. The impact of the system's dimensionality and of the strength of the spin-orbit interaction on the optical response is also discussed.

  15. One-dimensional versus two-dimensional electronic states in vicinal surfaces

    International Nuclear Information System (INIS)

    Ortega, J E; Ruiz-Oses, M; Cordon, J; Mugarza, A; Kuntze, J; Schiller, F

    2005-01-01

    Vicinal surfaces with periodic arrays of steps are among the simplest lateral nanostructures. In particular, noble metal surfaces vicinal to the (1 1 1) plane are excellent test systems to explore the basic electronic properties in one-dimensional superlattices by means of angular photoemission. These surfaces are characterized by strong emissions from free-electron-like surface states that scatter at step edges. Thereby, the two-dimensional surface state displays superlattice band folding and, depending on the step lattice constant d, it splits into one-dimensional quantum well levels. Here we use high-resolution, angle-resolved photoemission to analyse surface states in a variety of samples, in trying to illustrate the changes in surface state bands as a function of d

  16. Densis. Densimetric representation of two-dimensional matrices

    International Nuclear Information System (INIS)

    Los Arcos Merino, J.M.

    1978-01-01

    Densis is a Fortran V program which allows off-line control of a Calcomp digital plotter, to represent a two-dimensional matrix of numerical elements in the form of a variable shading intensity map in two colours. Each matrix element is associated to a square of a grid which is traced over by lines whose number is a function of the element value according to a selected scale. Program features, subroutine structure and running instructions, are described. Some typical results, for gamma-gamma coincidence experimental data and a sampled two-dimensional function, are indicated. (author)

  17. Nonlinear two-stream interaction between a cold, relativistic electron beam and a collisional plasma-Astron experiment

    International Nuclear Information System (INIS)

    Newberger, B.S.; Thode, L.E.

    1979-05-01

    Experiments on the two-stream instability of a relativistic electron beam propagating through a neutral gas, carried out with the Lawrence Livermore Laboratory Astron beam, have been analyzed using a nonlinear saturation model for a cold beam. The behavior of the observed microwave emission due to the instability is in good agreement with that of the beam energy loss. Collisions on the plasma electrons weaken the nonlinear state of the instability but do not stabilize the mode. The beam essentially acts as if it were cold, a result substantiated by linear theory for waves propagating along the beam. In order to predict the effect of both beam momentum scatter and plasma electron collisions on the stability of the mode in future experiments a full two-dimensional linear theory must be developed

  18. A Fokker-Planck-Landau collision equation solver on two-dimensional velocity grid and its application to particle-in-cell simulation

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, E. S.; Chang, C. S., E-mail: cschang@pppl.gov [Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States); Korea Advanced Institute of Science and Technology, Yuseong-gu, DaeJeon 305-701 (Korea, Republic of)

    2014-03-15

    An approximate two-dimensional solver of the nonlinear Fokker-Planck-Landau collision operator has been developed using the assumption that the particle probability distribution function is independent of gyroangle in the limit of strong magnetic field. The isotropic one-dimensional scheme developed for nonlinear Fokker-Planck-Landau equation by Buet and Cordier [J. Comput. Phys. 179, 43 (2002)] and for linear Fokker-Planck-Landau equation by Chang and Cooper [J. Comput. Phys. 6, 1 (1970)] have been modified and extended to two-dimensional nonlinear equation. In addition, a method is suggested to apply the new velocity-grid based collision solver to Lagrangian particle-in-cell simulation by adjusting the weights of marker particles and is applied to a five dimensional particle-in-cell code to calculate the neoclassical ion thermal conductivity in a tokamak plasma. Error verifications show practical aspects of the present scheme for both grid-based and particle-based kinetic codes.

  19. Embedding Approach to Modeling Electromagnetic Fields in a Complex Two-Dimensional Environment

    Directory of Open Access Journals (Sweden)

    Anton Tijhuis

    2018-01-01

    Full Text Available An approach is presented to combine the response of a two-dimensionally inhomogeneous dielectric object in a homogeneous environment with that of an empty inhomogeneous environment. This allows an efficient computation of the scattering behavior of the dielectric cylinder with the aid of the CGFFT method and a dedicated extrapolation procedure. Since a circular observation contour is adopted, an angular spectral representation can be employed for the embedding. Implementation details are discussed for the case of a closed 434 MHz microwave scanner, and the accuracy and efficiency of all steps in the numerical procedure are investigated. Guidelines are proposed for choosing computational parameters such as truncation limits and tolerances. We show that the embedding approach does not increase the CPU time with respect to the forward problem solution in a homogeneous environment, if only the fields on the observation contour are computed, and that it leads to a relatively small increase when the fields on the mesh are computed as well.

  20. Nonlinear evolution of a three dimensional longitudinal plasma wavepacket in a hot plasma including the effect of its interaction with an ion-acoustic wave

    International Nuclear Information System (INIS)

    Das, K.P.; Sihi, S.

    1979-01-01

    Assuming amplitudes as slowly varying functions of space and time and using perturbation method three coupled nonlinear partial differential equations are obtained for the nonlinear evolution of a three dimensional longitudinal plasma wave packet in a hot plasma including the effect of its interaction with a long wavelength ion-acoustic wave. These three equations are used to derive the instability conditions of a uniform longitudinal plasma wave train including the effect of its interaction both at resonance and nonresonance, with a long wavelength ion-acoustic wave. (author)

  1. Self-organization of dissipative and coherent vortex structures in non-equilibrium magnetized two-dimensional plasmas

    International Nuclear Information System (INIS)

    Bystrenko, O; Bystrenko, T

    2010-01-01

    The properties of non-equilibrium magnetized plasmas confined in planar geometry are studied on the basis of first-principle microscopic Langevin dynamics computer simulations. The non-equilibrium state of plasmas is maintained due to the recombination and generation of charges. The intrinsic microscopic structure of non-equilibrium steady-state magnetized plasmas, in particular the inter-particle correlations and self-organization of vortex structures, are examined. The simulations have been performed for a wide range of parameters including strong plasma coupling, high charge recombination and generation rates and intense magnetic field. As is shown in simulations, the non-equilibrium recombination and generation processes trigger the formation of ordered dissipative or coherent drift vortex states in 2D plasmas with distinctly spatially separated components, which are far from thermal equilibrium. This is evident from the unusual properties of binary distributions and behavior of the Coulomb energy of the system, which turn out to be quite different from the ones typical for the equilibrium state of plasmas under the same conditions.

  2. Three-dimensional simulation of diamagnetic cavity formation by a finite-sized plasma beam

    International Nuclear Information System (INIS)

    Thomas, V.A.

    1989-01-01

    The problem of collisionless coupling between a plasma beam and a background plasma is examined using a three-dimensional hybrid code. The beam is assumed to be moving parallel to an ambient magnetic field at a speed greater than the local Alfven speed. In addition, the beam has a finite spatial extent in the directions perpendicular to the magnetic field and is uniform and infinite in the direction parallel to the ambient magnetic field. Such a system is susceptible to coupling of the beam ions with the background ions via an electromagnetic ion beam instability. This instability isotropizes the beam and energizes the background plasma. A large-amplitude Alfven wave traveling radially away from the interaction region is associated with the energized background plasma. The process described here is one which may be responsible for the formation of diamagnetic cavities observed in the solar wind. copyright American Geophysical Union 1989

  3. Observations and calculations of two-dimensional angular optical scattering (TAOS) patterns of a single levitated cluster of two and four microspheres

    International Nuclear Information System (INIS)

    Krieger, U.K.; Meier, P.

    2011-01-01

    We use single bi-sphere particles levitated in an electrodynamic balance to record two-dimensional angular scattering patterns at different angles of the coordinate system of the aggregate relative to the incident laser beam. Due to Brownian motion the particle covers the whole set of possible angles with time and allows to select patterns with high symmetry for analysis. These are qualitatively compared to numerical calculations. A small cluster of four spheres shows complex scattering patterns, comparison with computations suggest a low compactness for these clusters. An experimental procedure is proposed for studying restructuring effects occurring in mixed particles upon evaporation. - Research highlights: → Single levitated bi-sphere particle. → Two-dimensional angular scattering pattern. → Comparison experiment with computations.

  4. Visualization techniques in plasma numerical simulations

    International Nuclear Information System (INIS)

    Kulhanek, P.; Smetana, M.

    2004-01-01

    Numerical simulations of plasma processes usually yield a huge amount of raw numerical data. Information about electric and magnetic fields and particle positions and velocities can be typically obtained. There are two major ways of elaborating these data. First of them is called plasma diagnostics. We can calculate average values, variances, correlations of variables, etc. These results may be directly comparable with experiments and serve as the typical quantitative output of plasma simulations. The second possibility is the plasma visualization. The results are qualitative only, but serve as vivid display of phenomena in the plasma followed-up. An experience with visualizing electric and magnetic fields via Line Integral Convolution method is described in the first part of the paper. The LIC method serves for visualization of vector fields in two dimensional section of the three dimensional plasma. The field values can be known only in grid points of three-dimensional grid. The second part of the paper is devoted to the visualization techniques of the charged particle motion. The colour tint can be used for particle temperature representation. The motion can be visualized by a trace fading away with the distance from the particle. In this manner the impressive animations of the particle motion can be achieved. (author)

  5. A Novel Machine Learning Strategy Based on Two-Dimensional Numerical Models in Financial Engineering

    Directory of Open Access Journals (Sweden)

    Qingzhen Xu

    2013-01-01

    Full Text Available Machine learning is the most commonly used technique to address larger and more complex tasks by analyzing the most relevant information already present in databases. In order to better predict the future trend of the index, this paper proposes a two-dimensional numerical model for machine learning to simulate major U.S. stock market index and uses a nonlinear implicit finite-difference method to find numerical solutions of the two-dimensional simulation model. The proposed machine learning method uses partial differential equations to predict the stock market and can be extensively used to accelerate large-scale data processing on the history database. The experimental results show that the proposed algorithm reduces the prediction error and improves forecasting precision.

  6. Resonance fluorescence based two- and three-dimensional atom localization

    Science.gov (United States)

    Wahab, Abdul; Rahmatullah; Qamar, Sajid

    2016-06-01

    Two- and three-dimensional atom localization in a two-level atom-field system via resonance fluorescence is suggested. For the two-dimensional localization, the atom interacts with two orthogonal standing-wave fields, whereas for the three-dimensional atom localization, the atom interacts with three orthogonal standing-wave fields. The effect of the detuning and phase shifts associated with the corresponding standing-wave fields is investigated. A precision enhancement in position measurement of the single atom can be noticed via the control of the detuning and phase shifts.

  7. Toward two-dimensional search engines

    International Nuclear Information System (INIS)

    Ermann, L; Shepelyansky, D L; Chepelianskii, A D

    2012-01-01

    We study the statistical properties of various directed networks using ranking of their nodes based on the dominant vectors of the Google matrix known as PageRank and CheiRank. On average PageRank orders nodes proportionally to a number of ingoing links, while CheiRank orders nodes proportionally to a number of outgoing links. In this way, the ranking of nodes becomes two dimensional which paves the way for the development of two-dimensional search engines of a new type. Statistical properties of information flow on the PageRank–CheiRank plane are analyzed for networks of British, French and Italian universities, Wikipedia, Linux Kernel, gene regulation and other networks. A special emphasis is done for British universities networks using the large database publicly available in the UK. Methods of spam links control are also analyzed. (paper)

  8. Subjective figure reversal in two- and three-dimensional perceptual space.

    Science.gov (United States)

    Radilová, J; Radil-Weiss, T

    1984-08-01

    A permanently illuminated pattern of Mach's truncated pyramid can be perceived according to the experimental instruction given, either as a three-dimensional reversible figure with spontaneously changing convex and concave interpretation (in one experiment), or as a two-dimensional reversible figure-ground pattern (in another experiment). The reversal rate was about twice as slow, without the subjects being aware of it, if it was perceived as a three-dimensional figure compared to the situation when it was perceived as two-dimensional. It may be hypothetized that in the three-dimensional case, the process of perception requires more sequential steps than in the two-dimensional one.

  9. Full evaporation dynamic headspace in combination with selectable one-dimensional/two-dimensional gas chromatography-mass spectrometry for the determination of suspected fragrance allergens in cosmetic products.

    Science.gov (United States)

    Devos, Christophe; Ochiai, Nobuo; Sasamoto, Kikuo; Sandra, Pat; David, Frank

    2012-09-14

    Suspected fragrance allergens were determined in cosmetic products using a combination of full evaporation-dynamic headspace (FEDHS) with selectable one-dimensional/two-dimensional GC-MS. The full evaporation dynamic headspace approach allows the non-discriminating extraction and injection of both apolar and polar fragrance compounds, without contamination of the analytical system by high molecular weight non-volatile matrix compounds. The method can be applied to all classes of cosmetic samples, including water containing matrices such as shower gels or body creams. In combination with selectable (1)D/(2)D GC-MS, consisting of a dedicated heart-cutting GC-MS configuration using capillary flow technology (CFT) and low thermal mass GC (LTM-GC), a highly flexible and easy-to-use analytical solution is offered. Depending on the complexity of the perfume fraction, analyses can be performed in one-dimensional GC-MS mode or in heart-cutting two-dimensional GC-MS mode, without the need of hardware reconfiguration. The two-dimensional mode with independent temperature control of the first and second dimension column is especially useful to confirm the presence of detected allergen compounds when mass spectral deconvolution is not possible. Copyright © 2012 Elsevier B.V. All rights reserved.

  10. Investigation of Plasmas Having Complex, Dynamic Evolving Morphology

    Energy Technology Data Exchange (ETDEWEB)

    Bellan, Paul M. [California Inst. of Technology (CalTech), Pasadena, CA (United States)

    2017-01-03

    Three different types of plasmas have been investigated using both experimental and theoretical methods. The first type of plasma is dense, highly ionized, governed by magnetohydrodynamics, and highly dynamic. This plasma is relevant to solar coronal loops, astrophysical jets, and other situations where strong magnetic forces act on the plasma. A well-diagnosed laboratory experiment creates a magnetohydrodynamically driven highly collimated plasma jet. This jet undergoes a kink instability such that it rapidly develops a corkscrew shape. The kink causes lateral acceleration of the jet, and this lateral acceleration drives a Rayleigh-Taylor instability that in turn chokes the current flowing in the jet and causes a magnetic reconnection. The magnetic reconnection causes electron and ion heating as well as emission of whistler waves. This entire sequence of events has been observed, measured in detail, and related to theoretical models. The second type of plasma is a transient rf-produced plasma used as a seed plasma for the magnetohydrodynamic experiments described above. Detailed atomic physics ionization processes have been investigated and modeled. The third type of plasma that has been studied is a dusty plasma where the dust particles are spontaneously growing ice grains. The rapid growth of the ice grains to large size and their highly ordered alignment has been investigated as well as collective motion of the ice grains, including well-defined flows on the surface of nested toroids. In addition to the experimental work described above, several related theoretical models have been developed, most notably a model showing how a complex interaction between gravity and magnetic fields on extremely weakly ionized plasma in an accretion disk provides an electric power source that can drive astrophysical jets associated with the accretion disk. Eighteen papers reporting this work have been published in a wide variety of journals.

  11. Investigation of Plasmas Having Complex, Dynamic Evolving Morphology

    International Nuclear Information System (INIS)

    Bellan, Paul M.

    2017-01-01

    Three different types of plasmas have been investigated using both experimental and theoretical methods. The first type of plasma is dense, highly ionized, governed by magnetohydrodynamics, and highly dynamic. This plasma is relevant to solar coronal loops, astrophysical jets, and other situations where strong magnetic forces act on the plasma. A well-diagnosed laboratory experiment creates a magnetohydrodynamically driven highly collimated plasma jet. This jet undergoes a kink instability such that it rapidly develops a corkscrew shape. The kink causes lateral acceleration of the jet, and this lateral acceleration drives a Rayleigh-Taylor instability that in turn chokes the current flowing in the jet and causes a magnetic reconnection. The magnetic reconnection causes electron and ion heating as well as emission of whistler waves. This entire sequence of events has been observed, measured in detail, and related to theoretical models. The second type of plasma is a transient rf-produced plasma used as a seed plasma for the magnetohydrodynamic experiments described above. Detailed atomic physics ionization processes have been investigated and modeled. The third type of plasma that has been studied is a dusty plasma where the dust particles are spontaneously growing ice grains. The rapid growth of the ice grains to large size and their highly ordered alignment has been investigated as well as collective motion of the ice grains, including well-defined flows on the surface of nested toroids. In addition to the experimental work described above, several related theoretical models have been developed, most notably a model showing how a complex interaction between gravity and magnetic fields on extremely weakly ionized plasma in an accretion disk provides an electric power source that can drive astrophysical jets associated with the accretion disk. Eighteen papers reporting this work have been published in a wide variety of journals.

  12. Ctr9, a Protein in the Transcription Complex Paf1, Regulates Dopamine Transporter Activity at the Plasma Membrane.

    Science.gov (United States)

    De Gois, Stéphanie; Slama, Patrick; Pietrancosta, Nicolas; Erdozain, Amaia M; Louis, Franck; Bouvrais-Veret, Caroline; Daviet, Laurent; Giros, Bruno

    2015-07-17

    Dopamine (DA) is a major regulator of sensorimotor and cognitive functions. The DA transporter (DAT) is the key protein that regulates the spatial and temporal activity of DA release into the synaptic cleft via the rapid reuptake of DA into presynaptic termini. Several lines of evidence have suggested that transporter-interacting proteins may play a role in DAT function and regulation. Here, we identified the tetratricopeptide repeat domain-containing protein Ctr9 as a novel DAT binding partner using a yeast two-hybrid system. We showed that Ctr9 is expressed in dopaminergic neurons and forms a stable complex with DAT in vivo via GST pulldown and co-immunoprecipitation assays. In mammalian cells co-expressing both proteins, Ctr9 partially colocalizes with DAT at the plasma membrane. This interaction between DAT and Ctr9 results in a dramatic enhancement of DAT-mediated DA uptake due to an increased number of DAT transporters at the plasma membrane. We determined that the binding of Ctr9 to DAT requires residues YKF in the first half of the DAT C terminus. In addition, we characterized Ctr9, providing new insight into this protein. Using three-dimensional modeling, we identified three novel tetratricopeptide repeat domains in the Ctr9 sequence, and based on deletion mutation experiments, we demonstrated the role of the SH2 domain of Ctr9 in nuclear localization. Our results demonstrate that Ctr9 localization is not restricted to the nucleus, as previously described for the transcription complex Paf1. Taken together, our data provide evidence that Ctr9 modulates DAT function by regulating its trafficking. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  13. Turbulence Statistics in a Two-Dimensional Vortex Condensate

    Science.gov (United States)

    Frishman, Anna; Herbert, Corentin

    2018-05-01

    Disentangling the evolution of a coherent mean-flow and turbulent fluctuations, interacting through the nonlinearity of the Navier-Stokes equations, is a central issue in fluid mechanics. It affects a wide range of flows, such as planetary atmospheres, plasmas, or wall-bounded flows, and hampers turbulence models. We consider the special case of a two-dimensional flow in a periodic box, for which the mean flow, a pair of box-size vortices called "condensate," emerges from turbulence. As was recently shown, a perturbative closure describes correctly the condensate when turbulence is excited at small scales. In this context, we obtain explicit results for the statistics of turbulence, encoded in the Reynolds stress tensor. We demonstrate that the two components of the Reynolds stress, the momentum flux and the turbulent energy, are determined by different mechanisms. It was suggested previously that the momentum flux is fixed by a balance between forcing and mean-flow advection: using unprecedently long numerical simulations, we provide the first direct evidence supporting this prediction. By contrast, combining analytical computations with numerical simulations, we show that the turbulent energy is determined only by mean-flow advection and obtain for the first time a formula describing its profile in the vortex.

  14. Two multi-dimensional uncertainty relations

    International Nuclear Information System (INIS)

    Skala, L; Kapsa, V

    2008-01-01

    Two multi-dimensional uncertainty relations, one related to the probability density and the other one related to the probability density current, are derived and discussed. Both relations are stronger than the usual uncertainty relations for the coordinates and momentum

  15. Mechanical exfoliation of two-dimensional materials

    Science.gov (United States)

    Gao, Enlai; Lin, Shao-Zhen; Qin, Zhao; Buehler, Markus J.; Feng, Xi-Qiao; Xu, Zhiping

    2018-06-01

    Two-dimensional materials such as graphene and transition metal dichalcogenides have been identified and drawn much attention over the last few years for their unique structural and electronic properties. However, their rise begins only after these materials are successfully isolated from their layered assemblies or adhesive substrates into individual monolayers. Mechanical exfoliation and transfer are the most successful techniques to obtain high-quality single- or few-layer nanocrystals from their native multi-layer structures or their substrate for growth, which involves interfacial peeling and intralayer tearing processes that are controlled by material properties, geometry and the kinetics of exfoliation. This procedure is rationalized in this work through theoretical analysis and atomistic simulations. We propose a criterion to assess the feasibility for the exfoliation of two-dimensional sheets from an adhesive substrate without fracturing itself, and explore the effects of material and interface properties, as well as the geometrical, kinetic factors on the peeling behaviors and the torn morphology. This multi-scale approach elucidates the microscopic mechanism of the mechanical processes, offering predictive models and tools for the design of experimental procedures to obtain single- or few-layer two-dimensional materials and structures.

  16. On the heterogeneous character of the heartbeat instability in complex (dusty) plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Pustylnik, M. Y.; Ivlev, A. V.; Heidemann, R.; Mitic, S.; Thomas, H. M.; Morfill, G. E. [Max-Planck-Institut fuer Extraterrestrische Physik, Giessenbachstrasse, 85741 Garching (Germany); Sadeghi, N. [LIPhy, Universite de Grenoble 1/CNRS, UMR 5588, Grenoble 38401 (France)

    2012-10-15

    A hypothesis on the physical mechanism generating the heartbeat instability in complex (dusty) plasmas is presented. It is suggested that the instability occurs due to the periodically repeated critical transformation on the boundary between the microparticle-free area (void) and the complex plasma. The critical transformation is supposed to be analogous to the formation of the sheath in the vicinity of an electrode. The origin of the transformation is the loss of the electrons and ions on microparticles surrounding the void. We have shown that this hypothesis is consistent with the experimentally measured stability parameter range, with the evolution of the plasma glow intensity and microparticle dynamics during the instability, as well as with the observed excitation of the heartbeat instability by an intensity-modulated laser beam (inducing the modulation of plasma density).

  17. Mechanical design of the two dimensional beam emission spectroscopy diagnostics on mast

    Energy Technology Data Exchange (ETDEWEB)

    Kiss, Istvan Gabor, E-mail: kiss.istvan.gabor@rmki.kfki.hu [Association EURATOM, KFKI-RMKI, P.O. Box 49, H-1525 Budapest (Hungary); Meszaros, Botond; Dunai, Daniel; Zoletnik, Sandor; Krizsanoczi, Tibor [Association EURATOM, KFKI-RMKI, P.O. Box 49, H-1525 Budapest (Hungary); Field, Anthony R.; Gaffka, Rob [EURATOM/CCFE Fusion Association, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom)

    2011-10-15

    A two dimensional beam emission spectroscopy (BES) system optimized for density turbulence measurements has recently been installed on the MAST tokamak. This system observes the emission of a Deuterium heating beam using a rotatable mirror to view from the plasma centre to the outboard edge (0.7-1.5 m), although the optics is optimized for core region (1.2 m). The beam is imaged onto a 4x8 pixel Avalanche Photodiode (APD) array detector, enabling measurements with 1 MHz bandwidth at photon-flux level of few times 10{sup 11} photons/s. This article will present the mechanical design of MAST BES equipment with special emphasis on its in-vessel components.

  18. Images of Complex Interactions of an Intense Ion Beam with Plasma Electrons

    International Nuclear Information System (INIS)

    Kaganovich, Igor D.; Startsev, Edward; Davidson, Ronald C.

    2004-01-01

    Ion beam propagation in a background plasma is an important scientific issue for many practical applications. The process of ion beam charge and current neutralization is complex because plasma electrons move in strong electric and magnetic fields of the beam. Computer simulation images of plasma interaction with an intense ion beam pulse are presented

  19. The fabrication and cell culture of three-dimensional rolled scaffolds with complex micro-architectures

    International Nuclear Information System (INIS)

    Liu Yaxiong; Li Xiao; Qu Xiaoli; Zhu Lin; He Jiankang; Zhao Qian; Wu Wanquan; Li Dichen

    2012-01-01

    Cell cultures for tissue engineering are traditionally prepared on two-dimensional or three-dimensional scaffolds with simple pores; however, this limits mass transportation, which is necessary for cell viability and function. In this paper, an innovative method is proposed for fabricating porous scaffolds with designed complex micro-architectures. Channels devised by computer-aided design were used to simulate features of blood vessels in native rat liver. Rapid prototyping and microreplication were used to produce a negative polydimethylsiloxane mold, and then a planar porous scaffold with predefined microchannel parameters was obtained by freeze-drying a silk fibroin/gelatin solution of an optimized concentration. After seeding with rat primary hepatocytes, the planar scaffold was rolled up to build spatial channels. By reconstructing the three-dimensional channel model in the scaffold in the form of micro-computed topography data and observing the cross-sections of the scroll, we confirmed that the bent channels were still interconnected, with restricted deviations. A comparison of the primary hepatocyte culture in the scaffolds with and without the devised channels proved that our design influenced cell organization and improved cell survival and proliferation. This method can be used for the construction of complex tissues for implantation and for culturing cells in vitro for biological tests and observations.

  20. A Two Element Plasma Antenna Array

    Directory of Open Access Journals (Sweden)

    F. Sadeghikia

    2013-10-01

    Full Text Available This theoretical study presents the characteristics of plasma monopole antennas in the VHF/UHF range using finite difference time domain (FDTD simulation. Results show that more broadband characteristics can be obtained by increasing the diameter of the plasma tube and that the minor lobes diminish in intensity as diameter increases. Furthermore, the nulls are replaced by low level radiation. Since the collision frequency, which is a function of gas pressure, represents the loss mechanism of plasma, decreasing its value increases the gain and radar cross section (RCS of the antenna. Theoretical modeling shows that at higher plasma frequencies with respect to the signal frequency, the gain and radar cross section of the plasma antenna are high enough and that the impedance curves are altered as the plasma frequency varies. Using these preliminary studies, mutual impedance and gain of a broadside array of two parallel side-by-side plasma elements is presented.

  1. Comparison of surface extraction techniques performance in computed tomography for 3D complex micro-geometry dimensional measurements

    DEFF Research Database (Denmark)

    Torralba, Marta; Jiménez, Roberto; Yagüe-Fabra, José A.

    2018-01-01

    micro-geometries as well (i.e., in the sub-mm dimensional range). However, there are different factors that may influence the CT process performance, being one of them the surface extraction technique used. In this paper, two different extraction techniques are applied to measure a complex miniaturized......The number of industrial applications of computed tomography (CT) for dimensional metrology in 100–103 mm range has been continuously increasing, especially in the last years. Due to its specific characteristics, CT has the potential to be employed as a viable solution for measuring 3D complex...... dental file by CT in order to analyze its contribution to the final measurement uncertainty in complex geometries at the mm to sub-mm scales. The first method is based on a similarity analysis: the threshold determination; while the second one is based on a gradient or discontinuity analysis: the 3D...

  2. Mode suppression of a two-dimensional potential relaxation instability in a weakly magnetized discharge plasma

    Science.gov (United States)

    Gyergyek, T.; Čerček, M.; Jelić, N.; Stanojević, M.

    1993-05-01

    A potential relaxation instability (PRI) is modulated by an external signal using an additional grid to modulate the radial plasma potential profile in a magnetized plasma column in a linear magnetized discharge plasma device. It is observed that the electrode current oscillations follow the van der Pol equation with an external forcing term, and the linear growth rate of the instability is measured.

  3. Calculation of the spatial resolution in two-photon absorption spectroscopy applied to plasma diagnosis

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Lechuga, M. [Departamento de Física Teórica, Atómica y Óptica, Universidad de Valladolid, 47011-Valladolid (Spain); Laser Processing Group, Instituto de Óptica “Daza de Valdés,” CSIC, 28006-Madrid (Spain); Fuentes, L. M. [Departamento de Física Aplicada, Universidad de Valladolid, 47011-Valladolid (Spain); Grützmacher, K.; Pérez, C., E-mail: concha@opt.uva.es; Rosa, M. I. de la [Departamento de Física Teórica, Atómica y Óptica, Universidad de Valladolid, 47011-Valladolid (Spain)

    2014-10-07

    We report a detailed characterization of the spatial resolution provided by two-photon absorption spectroscopy suited for plasma diagnosis via the 1S-2S transition of atomic hydrogen for optogalvanic detection and laser induced fluorescence (LIF). A precise knowledge of the spatial resolution is crucial for a correct interpretation of measurements, if the plasma parameters to be analysed undergo strong spatial variations. The present study is based on a novel approach which provides a reliable and realistic determination of the spatial resolution. Measured irradiance distribution of laser beam waists in the overlap volume, provided by a high resolution UV camera, are employed to resolve coupled rate equations accounting for two-photon excitation, fluorescence decay and ionization. The resulting three-dimensional yield distributions reveal in detail the spatial resolution for optogalvanic and LIF detection and related saturation due to depletion. Two-photon absorption profiles broader than the Fourier transform-limited laser bandwidth are also incorporated in the calculations. The approach allows an accurate analysis of the spatial resolution present in recent and future measurements.

  4. Calculation of the spatial resolution in two-photon absorption spectroscopy applied to plasma diagnosis

    International Nuclear Information System (INIS)

    Garcia-Lechuga, M.; Fuentes, L. M.; Grützmacher, K.; Pérez, C.; Rosa, M. I. de la

    2014-01-01

    We report a detailed characterization of the spatial resolution provided by two-photon absorption spectroscopy suited for plasma diagnosis via the 1S-2S transition of atomic hydrogen for optogalvanic detection and laser induced fluorescence (LIF). A precise knowledge of the spatial resolution is crucial for a correct interpretation of measurements, if the plasma parameters to be analysed undergo strong spatial variations. The present study is based on a novel approach which provides a reliable and realistic determination of the spatial resolution. Measured irradiance distribution of laser beam waists in the overlap volume, provided by a high resolution UV camera, are employed to resolve coupled rate equations accounting for two-photon excitation, fluorescence decay and ionization. The resulting three-dimensional yield distributions reveal in detail the spatial resolution for optogalvanic and LIF detection and related saturation due to depletion. Two-photon absorption profiles broader than the Fourier transform-limited laser bandwidth are also incorporated in the calculations. The approach allows an accurate analysis of the spatial resolution present in recent and future measurements.

  5. LONGITUDINAL AND TRANSVERSAL PLASMA WAVE INSTABILITIES IN TWO COUNTERSTREAMING PLASMAS WITHOUT EXTERNAL FIELDS

    Energy Technology Data Exchange (ETDEWEB)

    Buenemann, D

    1963-03-15

    Some aspects of the theory of longitudinal and transversal waves in a collisionless nonrelativistic plasma are treated. A dispersion relation for multicomponent plasmas is derived from the linearized Boltzmann-Vlasov equation using the full set of Maxwell's equations without an external field. The velocity distributions of the plasma streams are assumed to be Maxwellian. For the particular case of two counterstreaming plasmas it is shown that there exists transversal instabilities for all counterstreaming velocities whereas the well known two stream instabilities only exist for velocities greater than a critical velocity. Exact solutions for the onset of the instabilities can be given. This kind of instability may occur for any nonisotropic velocity distribution in a collisionless plasma. (auth)

  6. Two-dimensional random arrays for real time volumetric imaging

    DEFF Research Database (Denmark)

    Davidsen, Richard E.; Jensen, Jørgen Arendt; Smith, Stephen W.

    1994-01-01

    real time volumetric imaging system, which employs a wide transmit beam and receive mode parallel processing to increase image frame rate. Depth-of-field comparisons were made from simulated on-axis and off-axis beamplots at ranges from 30 to 160 mm for both coaxial and offset transmit and receive......Two-dimensional arrays are necessary for a variety of ultrasonic imaging techniques, including elevation focusing, 2-D phase aberration correction, and real time volumetric imaging. In order to reduce system cost and complexity, sparse 2-D arrays have been considered with element geometries...... selected ad hoc, by algorithm, or by random process. Two random sparse array geometries and a sparse array with a Mills cross receive pattern were simulated and compared to a fully sampled aperture with the same overall dimensions. The sparse arrays were designed to the constraints of the Duke University...

  7. Computer simulation of phenomena in plasma via particles

    International Nuclear Information System (INIS)

    Alves, M.V.; Bittencourt, J.A.

    1988-06-01

    The method of plasma computer simulation via particles has become an efficient tool to investigate the time and spatial evolution of various physical phenomena in plasmas. This method is based on the study of the individual plasma particle motions interacting with one another and with the externally applied fields. Although fairly simple, it allows a non-linear analysis of complex plasma physical phenomena and to obtain diagnostics even for regions of the system where experimental measurements would be difficult to make. In this report, a general view of the electrostatic one-dimensional computer code ES1, originally developed by A. Bruce Langdon, is presented. The main mathematical artifice in this code is the use of a spatial grid in which various plasma particles are represented by ''superparticles'', using a given shape function. The principal characteristics of the model, the approximations made and the mathematical methods used to solve the equations involved, are described. The specification of the input parameters which characterize the system, the initial conditions and the graphic diagnostics which can be utilized, are also described. Results are presented illustrating graphically the behavior of the plasma oscillations, the two-stream instability and the beam-plasma instability. (author) [pt

  8. Three-dimensional propagation and absorption of high frequency Gaussian beams in magnetoactive plasmas

    International Nuclear Information System (INIS)

    Nowak, S.; Orefice, A.

    1994-01-01

    In today's high frequency systems employed for plasma diagnostics, power heating, and current drive the behavior of the wave beams is appreciably affected by the self-diffraction phenomena due to their narrow collimation. In the present article the three-dimensional propagation of Gaussian beams in inhomogeneous and anisotropic media is analyzed, starting from a properly formulated dispersion relation. Particular attention is paid, in the case of electromagnetic electron cyclotron (EC) waves, to the toroidal geometry characterizing tokamak plasmas, to the power density evolution on the advancing wave fronts, and to the absorption features occurring when a beam crosses an EC resonant layer

  9. One-pot growth of two-dimensional lateral heterostructures via sequential edge-epitaxy

    Science.gov (United States)

    Sahoo, Prasana K.; Memaran, Shahriar; Xin, Yan; Balicas, Luis; Gutiérrez, Humberto R.

    2018-01-01

    Two-dimensional heterojunctions of transition-metal dichalcogenides have great potential for application in low-power, high-performance and flexible electro-optical devices, such as tunnelling transistors, light-emitting diodes, photodetectors and photovoltaic cells. Although complex heterostructures have been fabricated via the van der Waals stacking of different two-dimensional materials, the in situ fabrication of high-quality lateral heterostructures with multiple junctions remains a challenge. Transition-metal-dichalcogenide lateral heterostructures have been synthesized via single-step, two-step or multi-step growth processes. However, these methods lack the flexibility to control, in situ, the growth of individual domains. In situ synthesis of multi-junction lateral heterostructures does not require multiple exchanges of sources or reactors, a limitation in previous approaches as it exposes the edges to ambient contamination, compromises the homogeneity of domain size in periodic structures, and results in long processing times. Here we report a one-pot synthetic approach, using a single heterogeneous solid source, for the continuous fabrication of lateral multi-junction heterostructures consisting of monolayers of transition-metal dichalcogenides. The sequential formation of heterojunctions is achieved solely by changing the composition of the reactive gas environment in the presence of water vapour. This enables selective control of the water-induced oxidation and volatilization of each transition-metal precursor, as well as its nucleation on the substrate, leading to sequential edge-epitaxy of distinct transition-metal dichalcogenides. Photoluminescence maps confirm the sequential spatial modulation of the bandgap, and atomic-resolution images reveal defect-free lateral connectivity between the different transition-metal-dichalcogenide domains within a single crystal structure. Electrical transport measurements revealed diode-like responses across the

  10. Asymptotics for Two-dimensional Atoms

    DEFF Research Database (Denmark)

    Nam, Phan Thanh; Portmann, Fabian; Solovej, Jan Philip

    2012-01-01

    We prove that the ground state energy of an atom confined to two dimensions with an infinitely heavy nucleus of charge $Z>0$ and $N$ quantum electrons of charge -1 is $E(N,Z)=-{1/2}Z^2\\ln Z+(E^{\\TF}(\\lambda)+{1/2}c^{\\rm H})Z^2+o(Z^2)$ when $Z\\to \\infty$ and $N/Z\\to \\lambda$, where $E^{\\TF}(\\lambd......We prove that the ground state energy of an atom confined to two dimensions with an infinitely heavy nucleus of charge $Z>0$ and $N$ quantum electrons of charge -1 is $E(N,Z)=-{1/2}Z^2\\ln Z+(E^{\\TF}(\\lambda)+{1/2}c^{\\rm H})Z^2+o(Z^2)$ when $Z\\to \\infty$ and $N/Z\\to \\lambda$, where $E......^{\\TF}(\\lambda)$ is given by a Thomas-Fermi type variational problem and $c^{\\rm H}\\approx -2.2339$ is an explicit constant. We also show that the radius of a two-dimensional neutral atom is unbounded when $Z\\to \\infty$, which is contrary to the expected behavior of three-dimensional atoms....

  11. Two-dimensional vibrational-electronic spectroscopy

    Science.gov (United States)

    Courtney, Trevor L.; Fox, Zachary W.; Slenkamp, Karla M.; Khalil, Munira

    2015-10-01

    Two-dimensional vibrational-electronic (2D VE) spectroscopy is a femtosecond Fourier transform (FT) third-order nonlinear technique that creates a link between existing 2D FT spectroscopies in the vibrational and electronic regions of the spectrum. 2D VE spectroscopy enables a direct measurement of infrared (IR) and electronic dipole moment cross terms by utilizing mid-IR pump and optical probe fields that are resonant with vibrational and electronic transitions, respectively, in a sample of interest. We detail this newly developed 2D VE spectroscopy experiment and outline the information contained in a 2D VE spectrum. We then use this technique and its single-pump counterpart (1D VE) to probe the vibrational-electronic couplings between high frequency cyanide stretching vibrations (νCN) and either a ligand-to-metal charge transfer transition ([FeIII(CN)6]3- dissolved in formamide) or a metal-to-metal charge transfer (MMCT) transition ([(CN)5FeIICNRuIII(NH3)5]- dissolved in formamide). The 2D VE spectra of both molecules reveal peaks resulting from coupled high- and low-frequency vibrational modes to the charge transfer transition. The time-evolving amplitudes and positions of the peaks in the 2D VE spectra report on coherent and incoherent vibrational energy transfer dynamics among the coupled vibrational modes and the charge transfer transition. The selectivity of 2D VE spectroscopy to vibronic processes is evidenced from the selective coupling of specific νCN modes to the MMCT transition in the mixed valence complex. The lineshapes in 2D VE spectra report on the correlation of the frequency fluctuations between the coupled vibrational and electronic frequencies in the mixed valence complex which has a time scale of 1 ps. The details and results of this study confirm the versatility of 2D VE spectroscopy and its applicability to probe how vibrations modulate charge and energy transfer in a wide range of complex molecular, material, and biological systems.

  12. Two-dimensional vibrational-electronic spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Courtney, Trevor L.; Fox, Zachary W.; Slenkamp, Karla M.; Khalil, Munira, E-mail: mkhalil@uw.edu [Department of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195 (United States)

    2015-10-21

    Two-dimensional vibrational-electronic (2D VE) spectroscopy is a femtosecond Fourier transform (FT) third-order nonlinear technique that creates a link between existing 2D FT spectroscopies in the vibrational and electronic regions of the spectrum. 2D VE spectroscopy enables a direct measurement of infrared (IR) and electronic dipole moment cross terms by utilizing mid-IR pump and optical probe fields that are resonant with vibrational and electronic transitions, respectively, in a sample of interest. We detail this newly developed 2D VE spectroscopy experiment and outline the information contained in a 2D VE spectrum. We then use this technique and its single-pump counterpart (1D VE) to probe the vibrational-electronic couplings between high frequency cyanide stretching vibrations (ν{sub CN}) and either a ligand-to-metal charge transfer transition ([Fe{sup III}(CN){sub 6}]{sup 3−} dissolved in formamide) or a metal-to-metal charge transfer (MMCT) transition ([(CN){sub 5}Fe{sup II}CNRu{sup III}(NH{sub 3}){sub 5}]{sup −} dissolved in formamide). The 2D VE spectra of both molecules reveal peaks resulting from coupled high- and low-frequency vibrational modes to the charge transfer transition. The time-evolving amplitudes and positions of the peaks in the 2D VE spectra report on coherent and incoherent vibrational energy transfer dynamics among the coupled vibrational modes and the charge transfer transition. The selectivity of 2D VE spectroscopy to vibronic processes is evidenced from the selective coupling of specific ν{sub CN} modes to the MMCT transition in the mixed valence complex. The lineshapes in 2D VE spectra report on the correlation of the frequency fluctuations between the coupled vibrational and electronic frequencies in the mixed valence complex which has a time scale of 1 ps. The details and results of this study confirm the versatility of 2D VE spectroscopy and its applicability to probe how vibrations modulate charge and energy transfer in a

  13. Analysis of 16 plasma vortex events in the geomagnetic tail

    International Nuclear Information System (INIS)

    Birn, J.; Hones, E.W. Jr.; Bame, S.J.; Russel, C.T.

    1985-01-01

    The analysis of 16 plasma vortex occurrences in the magnetotail plasma sheet of Hones et al. (1983) is extended. We used two- and three-dimensional plasma measurements and three-dimensional magnetic field measurements to study phase relations, energy propagation, and polarization properties. The results point toward an interpretation as a slow strongly damped MHD eigenmode which is generated by tailward traveling perturbations at the low-latitude interface between plasma sheet and magnetosheath

  14. Mixing times in quantum walks on two-dimensional grids

    International Nuclear Information System (INIS)

    Marquezino, F. L.; Portugal, R.; Abal, G.

    2010-01-01

    Mixing properties of discrete-time quantum walks on two-dimensional grids with toruslike boundary conditions are analyzed, focusing on their connection to the complexity of the corresponding abstract search algorithm. In particular, an exact expression for the stationary distribution of the coherent walk over odd-sided lattices is obtained after solving the eigenproblem for the evolution operator for this particular graph. The limiting distribution and mixing time of a quantum walk with a coin operator modified as in the abstract search algorithm are obtained numerically. On the basis of these results, the relation between the mixing time of the modified walk and the running time of the corresponding abstract search algorithm is discussed.

  15. Computation of drag and lift coefficients for simple two-dimensional objects with Reynolds number Re = 420 000

    Directory of Open Access Journals (Sweden)

    Matas Richard

    2012-04-01

    Full Text Available The article deals with comparison of drag and lift coefficients for simple two-dimensional objects, which are often discussed in fluid mechanics fundamentals books. The commercial CFD software ANSYS/FLUENT 13 was used for computation of flow fields around the objects and determination of the drag and lift coefficients. The flow fields of the two-dimensional objects were computed for velocity up to 160 km per hour and Reynolds number Re = 420 000. Main purpose was to verify the suggested computational domain and model settings for further more complex objects geometries. The more complex profiles are used to stabilize asymmetrical ('z'-shaped pantographs of high-speed trains. The trains are used in two-way traffic where the pantographs have to operate with the same characteristics in both directions. Results of the CFD computations show oscillation of the drag and lift coefficients over time. The results are compared with theoretical and experimental data and discussed. Some examples are presented in the paper.

  16. Approximate Riemann solver for the two-fluid plasma model

    International Nuclear Information System (INIS)

    Shumlak, U.; Loverich, J.

    2003-01-01

    An algorithm is presented for the simulation of plasma dynamics using the two-fluid plasma model. The two-fluid plasma model is more general than the magnetohydrodynamic (MHD) model often used for plasma dynamic simulations. The two-fluid equations are derived in divergence form and an approximate Riemann solver is developed to compute the fluxes of the electron and ion fluids at the computational cell interfaces and an upwind characteristic-based solver to compute the electromagnetic fields. The source terms that couple the fluids and fields are treated implicitly to relax the stiffness. The algorithm is validated with the coplanar Riemann problem, Langmuir plasma oscillations, and the electromagnetic shock problem that has been simulated with the MHD plasma model. A numerical dispersion relation is also presented that demonstrates agreement with analytical plasma waves

  17. Spin dynamics in a two-dimensional quantum gas

    DEFF Research Database (Denmark)

    Pedersen, Poul Lindholm; Gajdacz, Miroslav; Deuretzbacher, Frank

    2014-01-01

    We have investigated spin dynamics in a two-dimensional quantum gas. Through spin-changing collisions, two clouds with opposite spin orientations are spontaneously created in a Bose-Einstein condensate. After ballistic expansion, both clouds acquire ring-shaped density distributions with superimp......We have investigated spin dynamics in a two-dimensional quantum gas. Through spin-changing collisions, two clouds with opposite spin orientations are spontaneously created in a Bose-Einstein condensate. After ballistic expansion, both clouds acquire ring-shaped density distributions...

  18. Reduced, three-dimensional, nonlinear equations for high-β plasmas including toroidal effects

    International Nuclear Information System (INIS)

    Schmalz, R.

    1980-11-01

    The resistive MHD equations for toroidal plasma configurations are reduced by expanding to the second order in epsilon, the inverse aspect ratio, allowing for high β = μsub(o)p/B 2 of order epsilon. The result is a closed system of nonlinear, three-dimensional equations where the fast magnetohydrodynamic time scale is eliminated. In particular, the equation for the toroidal velocity remains decoupled. (orig.)

  19. Two-Dimensional, Time-Dependent Plasma Structures of a Hall Effect Thruster

    Science.gov (United States)

    2011-09-01

    atmospheric pressure to 80 mtorr, is accomplished by a Leybold-Trivac rotary van vacuum pump and the second stage is completed by four 20 in CVI...Thruster”. Physics of Plasmas, 13, 2006. 3. Albarede, Luc, Vanessa Vial, Alexey Lazurenko, Andre Bouchoule, and Michel Dudeck. “Low Frequency Dynamical...Force Research Laboratory Space and Missile Division (AFRL/RZS) 5 Pollux Drive Edwards AFB, CA 93524 DSN 525-5230 AFRL/RZS Approval for public release

  20. Procedures for two-dimensional electrophoresis of proteins

    Energy Technology Data Exchange (ETDEWEB)

    Tollaksen, S.L.; Giometti, C.S.

    1996-10-01

    High-resolution two-dimensional gel electrophoresis (2DE) of proteins, using isoelectric focusing in the first dimension and sodium dodecyl sulfate/polyacrylamide gel electrophoresis (SDS-PAGE) in the second, was first described in 1975. In the 20 years since those publications, numerous modifications of the original method have evolved. The ISO-DALT system of 2DE is a high-throughput approach that has stood the test of time. The problem of casting many isoelectric focusing gels and SDS-PAGE slab gels (up to 20) in a reproducible manner has been solved by the use of the techniques and equipment described in this manual. The ISO-DALT system of two-dimensional gel electrophoresis originated in the late 1970s and has been modified many times to improve its high-resolution, high-throughput capabilities. This report provides the detailed procedures used with the current ISO-DALT system to prepare, run, stain, and photograph two-dimensional gels for protein analysis.