Study of linear and non-linear waves propagation. Application to fluid mechanics and plasmas physics
Forestier, A.
2002-01-01
This contribution's topic is the resolution of the hyperbolic system which describes a compressible flow in perfect or real situation. It is always in a compressible case and a turbulent model or a multicomponent isentropic turbulent model can be associated. Different schemes are tested as S α β scheme or TVD scheme. An extension to generalized geometry is purposed in 2D or 3D. For chemical aspects, the ZND theory is under control with connexion of second order method. In the same way, MHD or Turbulent problem are developed with computations for compressible situation. Implicit aspects are investigated that show the lost of knowledge in large CFL even if computation can be driven for all time step. At the end, for Plasma situations in which pressure effects can be neglected, there is a lost of hyperbolicity that requires investigation in generated problems. We don't present numerical simulations that are exhibited in an other paper. (author)
Vlasov Fluid stability of a 2-D plasma with a linear magnetic field null
Kim, J.S.
1984-01-01
Vlasov Fluid stability of a 2-dimensional plasma near an O type magnetic null is investigated. Specifically, an elongated Z-pinch is considered, and applied to Field Reversed Configurations at Los Alamos National Laboratory by making a cylindrical approximation of the compact torus. The orbits near an elliptical O type null are found to be very complicated; the orbits are large and some are stochastic. The kinetic corrections to magnetohydrodynamics (MHD) are investigated by evaluating the expectation values of the growth rates of a Vlasov Fluid dispersion functional by using a set of trial functions based on ideal MHD. The dispersion functional involves fluid parts and orbit dependent parts. The latter involves phase integral of two time correlations. The phase integral is replaced by the time integral both for the regular and for the stochastic orbits. Two trial functions are used; one has a large displacement near the null and the other away from the null
A symbiotic approach to fluid equations and non-linear flux-driven simulations of plasma dynamics
Halpern, Federico
2017-10-01
The fluid framework is ubiquitous in studies of plasma transport and stability. Typical forms of the fluid equations are motivated by analytical work dating several decades ago, before computer simulations were indispensable, and can be, therefore, not optimal for numerical computation. We demonstrate a new first-principles approach to obtaining manifestly consistent, skew-symmetric fluid models, ensuring internal consistency and conservation properties even in discrete form. Mass, kinetic, and internal energy become quadratic (and always positive) invariants of the system. The model lends itself to a robust, straightforward discretization scheme with inherent non-linear stability. A simpler, drift-ordered form of the equations is obtained, and first results of their numerical implementation as a binary framework for bulk-fluid global plasma simulations are demonstrated. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Fusion Energy Sciences, Theory Program, under Award No. DE-FG02-95ER54309.
Anon.
1986-01-01
Plasma and fluid physics includes the fields of fusion research and space investigation. This book discusses the most important advances in these areas over the past decade and recommends a stronger commitment to basic research in plasma and fluid physics. The book recommends that plasma and fluid physics be included in physics curriculums because of their increasing importance in energy and defense. The book also lists recent accomplishments in the fields of general plasma physics, fusion plasma confinement and heating, space and astrophysical plasmas, and fluid physics and lists research opportunities in these areas. A funding summary explains how research monies are allocated and suggests ways to improve their effectiveness
Equilibrium and linear analysis of rotating plasmas: fluid and guiding center results
Iacono, R.
1990-06-01
This work is devoted to the equilibrium and stability of rotating plasmas. Apart from its theoretical interest, this subject has become of practical importance in fusion research, due to the use in recent tokamak experiments of auxiliary heating methods such as neutral-beam injection, which can produce large plasma flows. Flow velocities up to the ion sound speed have been measured on different machines and new phenomena associated with the flow, such as distorsions of the plasma equilibrium profiles, have been observed. As a consequence, flows must be included in the macroscopic description of plasma equilibrium, which is the basis for the analysis and the design of magnetic confinement machines, and the stability properties of equilibria with flows need to be investigated. Here, attention is centered on toroidal confinement machines and in particular on tokamaks. However, some of the results to be presented may be of interest also for other domains (strong mass flows also occur in astrophysical and geophysical contexts such as in the Jovian magnetosphere or in the Earth's magnetopause and plasmapause. It should be noted that equilibrium and, in particular, stability with flows are poorly understood at present. Therefore, many of the questions we will consider are of quite a general nature. We are not yet at the point where quantitative comparisons with specific experiments can be made. Even the choice of a convenient model to study plasma flow is far from being evident. So far most of the theoretical investigations have used the magnetohydrodynamic (MHD) model, which is one of the simplest descriptions of a plasma. In this work, however, it will be shown that, for rotating plasmas, the 'simple' MHD model can give very complicated and physically meaningless results, while more 'complicated' models can provide a simpler and more realistic description of the plasma behaviour. 65 refs., 8 figs., 3 tabs
Local linear viscoelasticity of confined fluids.
Hansen, J S; Daivis, P J; Todd, B D
2007-04-14
In this paper the authors propose a novel method to study the local linear viscoelasticity of fluids confined between two walls. The method is based on the linear constitutive equation and provides details about the real and imaginary parts of the local complex viscosity. They apply the method to a simple atomic fluid undergoing zero mean oscillatory flow using nonequilibrium molecular dynamics simulations. The method shows that the viscoelastic properties of the fluid exhibit dramatic spatial changes near the wall-fluid boundary due to the high density in this region. It is also shown that the real part of the viscosity converges to the frequency dependent local shear viscosity sufficiently far away from the wall. This also provides valuable information about the transport properties in the fluid, in general. The viscosity is compared with predictions from the local average density model. The two methods disagree in that the local average density model predicts larger viscosity variations near the wall-fluid boundary than what is observed through the method presented here.
Parallel plasma fluid turbulence calculations
Leboeuf, J.N.; Carreras, B.A.; Charlton, L.A.; Drake, J.B.; Lynch, V.E.; Newman, D.E.; Sidikman, K.L.; Spong, D.A.
1994-01-01
The study of plasma turbulence and transport is a complex problem of critical importance for fusion-relevant plasmas. To this day, the fluid treatment of plasma dynamics is the best approach to realistic physics at the high resolution required for certain experimentally relevant calculations. Core and edge turbulence in a magnetic fusion device have been modeled using state-of-the-art, nonlinear, three-dimensional, initial-value fluid and gyrofluid codes. Parallel implementation of these models on diverse platforms--vector parallel (National Energy Research Supercomputer Center's CRAY Y-MP C90), massively parallel (Intel Paragon XP/S 35), and serial parallel (clusters of high-performance workstations using the Parallel Virtual Machine protocol)--offers a variety of paths to high resolution and significant improvements in real-time efficiency, each with its own advantages. The largest and most efficient calculations have been performed at the 200 Mword memory limit on the C90 in dedicated mode, where an overlap of 12 to 13 out of a maximum of 16 processors has been achieved with a gyrofluid model of core fluctuations. The richness of the physics captured by these calculations is commensurate with the increased resolution and efficiency and is limited only by the ingenuity brought to the analysis of the massive amounts of data generated
Possible limits of plasma linear colliders
Zimmermann, F.
2017-07-01
Plasma linear colliders have been proposed as next or next-next generation energy-frontier machines for high-energy physics. I investigate possible fundamental limits on energy and luminosity of such type of colliders, considering acceleration, multiple scattering off plasma ions, intrabeam scattering, bremsstrahlung, and betatron radiation. The question of energy efficiency is also addressed.
Global numerical modeling of magnetized plasma in a linear device
Magnussen, Michael Løiten
Understanding the turbulent transport in the plasma-edge in fusion devices is of utmost importance in order to make precise predictions for future fusion devices. The plasma turbulence observed in linear devices shares many important features with the turbulence observed in the edge of fusion dev...... with simulations performed at different ionization levels, using a simple model for plasma interaction with neutrals. It is found that the steady state and the saturated state of the system bifurcates when the neutral interaction dominates the electron-ion collisions.......Understanding the turbulent transport in the plasma-edge in fusion devices is of utmost importance in order to make precise predictions for future fusion devices. The plasma turbulence observed in linear devices shares many important features with the turbulence observed in the edge of fusion...... devices, and are easier to diagnose due to lower temperatures and a better access to the plasma. In order to gain greater insight into this complex turbulent behavior, numerical simulations of plasma in a linear device are performed in this thesis. Here, a three-dimensional drift-fluid model is derived...
Towards a collisionless fluid closure in plasma turbulence
Dif Pradalier, G
2005-07-01
In this work 2 generic possible descriptions of a plasma have been compared namely the kinetic and the fluid approaches. The latter focuses on the successive moments (n, u, p, q,...) of the distribution function, whereas the former describes the time-evolution in phase space of this distribution function, both being based on the Vlasov equation. The fluid description is attractive for the Vlasov equation is tractable with great difficulties. Nevertheless it rests on a major difficulty: as the set of fluid equations constitute an infinite hierarchy, a closure equation must be chosen. The first chapter details physical characteristics of a fundamental kinetic interaction mechanism between waves and particles. In chapter 2 we propose a fluid closure that allows analytic comparison with a linear fully kinetic result, near an homogeneous, electrostatic, Maxwellian equilibrium. This approach consists in adjusting chosen parameters in order to minimize the discrepancies between fluid and kinetic linear response functions. In chapter 3 we present a general frame for a fluid closure in a magnetized plasma. This is attempted in a linear, simplified model with low dimensionality.
Linear wave propagation in a hot axisymmetric toroidal plasma
Jaun, A.
1995-03-01
Kinetic effects on the propagation of the Alfven wave are studied for the first time in a toroidal plasma relevant for experiments. This requires the resolution of a set of coupled partial differential equations whose coefficients depend locally on the plasma parameters. For this purpose, a numerical wave propagation code called PENN has been developed using either a bilinear or a bicubic Hermite finite element discretization. It solves Maxwell's equations in toroidal geometry, with a dielectric tensor operator that takes into account the linear response of the plasma. Two different models have been implemented and can be used comparatively to describe the same physical case: the first treats the plasma as resistive fluids and gives results which are in good agreement with toroidal fluid codes. The second is a kinetic model and takes into account the finite size of the Larmor radii; it has successfully been tested against a kinetic plasma model in cylindrical geometry. New results have been obtained when studying kinetic effects in toroidal geometry. Two different conversion mechanisms to the kinetic Alfven wave have been described: one occurs at toroidally coupled resonant surfaces and is the kinetic counterpart of the fluid models' resonance absorption. The other has no such correspondence and results directly from the toroidal coupling between the kinetic Alfven wave and the global wavefield. An analysis of a heating scenario suggests that it might be difficult to heat a plasma with Alfven waves up to temperatures that are relevant for a tokamak reactor. Kinetic effects are studied for three types of global Alfven modes (GAE, TAE, BAE) and a new class of kinetic eigenmodes is described which appear inside the fluid gap: it could be related to recent observations in the JET (Joint European Torus) tokamak. (author) 56 figs., 6 tabs., 58 refs
Linear wave propagation in a hot axisymmetric toroidal plasma
Jaun, A [Ecole Polytechnique Federale, Lausanne (Switzerland). Centre de Recherche en Physique des Plasma (CRPP)
1995-03-01
Kinetic effects on the propagation of the Alfven wave are studied for the first time in a toroidal plasma relevant for experiments. This requires the resolution of a set of coupled partial differential equations whose coefficients depend locally on the plasma parameters. For this purpose, a numerical wave propagation code called PENN has been developed using either a bilinear or a bicubic Hermite finite element discretization. It solves Maxwell`s equations in toroidal geometry, with a dielectric tensor operator that takes into account the linear response of the plasma. Two different models have been implemented and can be used comparatively to describe the same physical case: the first treats the plasma as resistive fluids and gives results which are in good agreement with toroidal fluid codes. The second is a kinetic model and takes into account the finite size of the Larmor radii; it has successfully been tested against a kinetic plasma model in cylindrical geometry. New results have been obtained when studying kinetic effects in toroidal geometry. Two different conversion mechanisms to the kinetic Alfven wave have been described: one occurs at toroidally coupled resonant surfaces and is the kinetic counterpart of the fluid models` resonance absorption. The other has no such correspondence and results directly from the toroidal coupling between the kinetic Alfven wave and the global wavefield. An analysis of a heating scenario suggests that it might be difficult to heat a plasma with Alfven waves up to temperatures that are relevant for a tokamak reactor. Kinetic effects are studied for three types of global Alfven modes (GAE, TAE, BAE) and a new class of kinetic eigenmodes is described which appear inside the fluid gap: it could be related to recent observations in the JET (Joint European Torus) tokamak. (author) 56 figs., 6 tabs., 58 refs.
Laboratory beam-plasma interactions linear and nonlinear
Christiansen, P.J.; Bond, J.W.; Jain, V.K.
1982-01-01
This chapter attempts to demonstrate that despite unavoidable scaling limitations, laboratory experiments can uncover details of beam plasma interaction processes which could never be revealed through space plasma physics. Topics covered include linear theory, low frequency couplings, indirect effects, nonlinear effects, quasi-linear effects, trapping effects, nonlinear wave-wave interactions, and self modulation and cavitation. Unstable electrostatic waves arising from an exchange of energy with the ''free energy'' beam features are considered as kinetic and as hydrodynamic, or fluid, instabilities. The consequences of such instabilities (e.g. when the waves have grown to a finite level) are examined and some studies are reviewed which have attempted to understand how the free energy originally available in the beam is redistributed to produce a final state of equilibrium turbulence
Fluid model of the magnetic presheath in a turbulent plasma
Stanojevic, M; Duhovnik, J; Jelic, N; Kendl, A; Kuhn, S
2005-01-01
A fluid model of the magnetic presheath in a turbulent boundary plasma is presented. Turbulent transport corrections of the classical three-dimensional fluid transport equations, which can be used to study magnetic presheaths in various geometries, are derived by means of the ensemble averaging procedure from the statistical theory of plasma turbulence. Then, the magnetic presheath in front of an infinite plane surface is analysed in detail. The linearized planar magnetic presheath equations are applied to the plasma-presheath-magnetic-presheath boundary (i.e. the magnetic presheath edge), whereas the original non-linear planar magnetic presheath equations are used for the entire magnetic presheath, allowing for various sets of experimentally relevant free model parameters to be applied. Important new results of this study are, among others, new expressions for the fluid Bohm criterion at the Debye sheath edge and for the ion flux density perpendicular to the wall. These new results, which exhibit corrections due to the turbulent charged particle transport, can qualitatively explain the fact that whenever the angle between the magnetic field and the wall is very small (i.e. several degrees) or zero, electric currents, measured by Langmuir probes in the boundary regions of nuclear fusion devices and in various low-temperature plasmas, are anomalously enhanced in comparison with those expected or predicted by other theoretical models
Vortex dynamics in plasmas and fluids
Juul Rasmussen, J.; Lynov, Jens-Peter; Hesthaven, J.S.
1994-01-01
The existence and dynamics of vortical structures in both homogeneous and inhomogeneous systems will be discussed. In particular the dynamics of monopolar and dipolar vortices in a plasma with nonuniform density and in a rotating fluid with varying Coriolis force is described. The role of vortica...
Poisson brackets for fluids and plasmas
Morrison, P.J.
1982-01-01
Noncanonical yet Hamiltonian descriptions are presented of many of the non-dissipative field equations that govern fluids and plasmas. The dynamical variables are the usually encountered physical variables. These descriptions have the advantage that gauge conditions are absent, but at the expense of introducing peculiar Poisson brackets. Clebsch-like potential descriptions that reverse this situations are also introduced
Linear instability and nonlinear motion of rotating plasma
Liu, J.
1985-01-01
Two coupled nonlinear equations describing the flute dynamics of the magnetically confined low-β collisionless rotating plasma are derived. The linear instability and nonlinear dynamics of the rotating column are analyzed theoretically. In the linear stability analysis, a new sufficient condition of stability is obtained. From the exact solution of eigenvalue equation for Gaussian density profile and uniform rotation of the plasma, the stability of the system strongly depends on the direction of plasma rotation, FLR effect and the location of the conducting wall. An analytic expression showing the finite wall effect on different normal modes is obtained and it explains the different behavior of (1,0) normal mode from other modes. The sheared rotation driven instability is investigated by using three model equilibrium profiles, and the analytic expressions of eigenvalues which includes the wall effect are obtained. The analogy between shear rotation driven instability and the instability driven by sheared plane parallel flow in the inviscid fluid is analyzed. Applying the linear analysis to the central cell of tandem mirror system, the trapped particle instability with only passing electronics is analyzed. For uniform rotation and Gaussian density profile, an analytic expression that determines the stability boundary is found. The nonlinear analysis shows that the nonlinear equations have a solitary vortex solution which is very similar to the vortex solution of nonlinear Rossby wave equation
Linear mode conversion in a toroidal plasma
Hellsten, T.
1980-05-01
Linear mode conversion at the perpendicular ion cyclotron resonance has been treated for an axially symmetric toroidal plasma. The mode conversion appears between a fast electromagnetic wave and a slow-quasi electrostatic wave, due to finite electron inertia. The problem reduces to the Orr-Sommerfeld equation where the coefficients determining the reflectron, transmission and conversion are functions of the arc length along a poloidal intersection of the resonance surface. These coefficients can be determined from eigenfunctions of an ordinary differential equation. (author)
Stability of non-linear constitutive formulations for viscoelastic fluids
Siginer, Dennis A
2014-01-01
Stability of Non-linear Constitutive Formulations for Viscoelastic Fluids provides a complete and up-to-date view of the field of constitutive equations for flowing viscoelastic fluids, in particular on their non-linear behavior, the stability of these constitutive equations that is their predictive power, and the impact of these constitutive equations on the dynamics of viscoelastic fluid flow in tubes. This book gives an overall view of the theories and attendant methodologies developed independently of thermodynamic considerations as well as those set within a thermodynamic framework to derive non-linear rheological constitutive equations for viscoelastic fluids. Developments in formulating Maxwell-like constitutive differential equations as well as single integral constitutive formulations are discussed in the light of Hadamard and dissipative type of instabilities.
Hamiltonian closures in fluid models for plasmas
Tassi, Emanuele
2017-11-01
This article reviews recent activity on the Hamiltonian formulation of fluid models for plasmas in the non-dissipative limit, with emphasis on the relations between the fluid closures adopted for the different models and the Hamiltonian structures. The review focuses on results obtained during the last decade, but a few classical results are also described, in order to illustrate connections with the most recent developments. With the hope of making the review accessible not only to specialists in the field, an introduction to the mathematical tools applied in the Hamiltonian formalism for continuum models is provided. Subsequently, we review the Hamiltonian formulation of models based on the magnetohydrodynamics description, including those based on the adiabatic and double adiabatic closure. It is shown how Dirac's theory of constrained Hamiltonian systems can be applied to impose the incompressibility closure on a magnetohydrodynamic model and how an extended version of barotropic magnetohydrodynamics, accounting for two-fluid effects, is amenable to a Hamiltonian formulation. Hamiltonian reduced fluid models, valid in the presence of a strong magnetic field, are also reviewed. In particular, reduced magnetohydrodynamics and models assuming cold ions and different closures for the electron fluid are discussed. Hamiltonian models relaxing the cold-ion assumption are then introduced. These include models where finite Larmor radius effects are added by means of the gyromap technique, and gyrofluid models. Numerical simulations of Hamiltonian reduced fluid models investigating the phenomenon of magnetic reconnection are illustrated. The last part of the review concerns recent results based on the derivation of closures preserving a Hamiltonian structure, based on the Hamiltonian structure of parent kinetic models. Identification of such closures for fluid models derived from kinetic systems based on the Vlasov and drift-kinetic equations are presented, and
Turbulence theories and modelling of fluids and plasmas
Yoshizawa, Akira; Yokoi, Nobumitsu [Institute of Industrial Science, Univ. of Tokyo, Tokyo (Japan); Itoh, Sanae-I. [Research Institute for Applied Mechanics, Kyushu Univ., Kasuga, Fukuoka (Japan); Itoh, Kimitaka [National Inst. for Fusion Science, Toki, Gifu (Japan)
2001-04-01
Theoretical and heuristic modelling methods are reviewed for studying turbulence phenomena of fluids and plasmas. Emphasis is put on understanding of effects on turbulent characteristics due to inhomogeneities of field and plasma parameters. The similarity and dissimilarity between the methods for fluids and plasmas are sought in order to shed light on the properties that are shared or not by fluid and plasma turbulence. (author)
Non-linear seismic analysis of structures coupled with fluid
Descleve, P.; Derom, P.; Dubois, J.
1983-01-01
This paper presents a method to calculate non-linear structure behaviour under horizontal and vertical seismic excitation, making possible the full non-linear seismic analysis of a reactor vessel. A pseudo forces method is used to introduce non linear effects and the problem is solved by superposition. Two steps are used in the method: - Linear calculation of the complete model. - Non linear analysis of thin shell elements and calculation of seismic induced pressure originating from linear and non linear effects, including permanent loads and thermal stresses. Basic aspects of the mathematical formulation are developed. It has been applied to axi-symmetric shell element using a Fourier series solution. For the fluid interaction effect, a comparison is made with a dynamic test. In an example of application, the displacement and pressure time history are given. (orig./GL)
A quasi-linear gyrokinetic transport model for tokamak plasmas
Casati, A.
2009-10-01
After a presentation of some basics around nuclear fusion, this research thesis introduces the framework of the tokamak strategy to deal with confinement, hence the main plasma instabilities which are responsible for turbulent transport of energy and matter in such a system. The author also briefly introduces the two principal plasma representations, the fluid and the kinetic ones. He explains why the gyro-kinetic approach has been preferred. A tokamak relevant case is presented in order to highlight the relevance of a correct accounting of the kinetic wave-particle resonance. He discusses the issue of the quasi-linear response. Firstly, the derivation of the model, called QuaLiKiz, and its underlying hypotheses to get the energy and the particle turbulent flux are presented. Secondly, the validity of the quasi-linear response is verified against the nonlinear gyro-kinetic simulations. The saturation model that is assumed in QuaLiKiz, is presented and discussed. Then, the author qualifies the global outcomes of QuaLiKiz. Both the quasi-linear energy and the particle flux are compared to the expectations from the nonlinear simulations, across a wide scan of tokamak relevant parameters. Therefore, the coupling of QuaLiKiz within the integrated transport solver CRONOS is presented: this procedure allows the time-dependent transport problem to be solved, hence the direct application of the model to the experiment. The first preliminary results regarding the experimental analysis are finally discussed
BOOK REVIEW: Plasma and Fluid Turbulence: Theory and Modelling
Yoshizawa, A.; Itoh, S. I.; Itoh, K.
2003-03-01
in turn suppress the instabilities leading to an intermittent type of dynamics. In chapter 21 the authors finally come to one of their special interests, subcritical, or nonlinear, excitation of turbulence. This is mainly of interest in plasma regimes where there are no strong instabilities or in order to explain magnetic perturbations in situations where only electrostatic modes are linearly unstable. The final part of the book deals mainly with statistical aspects of plasma turbulence, starting with bifurcation and including discussions of the transition from an L-mode (low confinement) to an H-mode (high confinement state) of magnetic confinement of plasmas. This is another area of special expertise of the authors and it is very well written, giving detailed information of the subject area. In conclusion I find the book to be both very pedagogical and very up to date. It can be strongly recommended to researchers who quickly want to reach the research front in plasma turbulence for magnetic confinement starting with only a basic knowledge of plasma or fluid dynamics. It has its main strengths in the fluid and MHD parts, as well as in the statistical descriptions. Jan Weiland
Stauss, Sven; Muneoka, Hitoshi; Terashima, Kazuo
2018-02-01
Plasma science and technology has enabled advances in very diverse fields: micro- and nanotechnology, chemical synthesis, materials fabrication and, more recently, biotechnology and medicine. While many of the currently employed plasma tools and technologies are very advanced, the types of plasmas used in micro- and nanofabrication pose certain limits, for example, in treating heat-sensitive materials in plasma biotechnology and plasma medicine. Moreover, many physical properties of plasmas encountered in nature, and especially outer space, i.e. very-low-temperature plasmas or plasmas that occur in high-density media, are not very well understood. The present review gives a short account of laboratory plasmas generated under ’extreme’ conditions: at cryogenic temperatures and in supercritical fluids. The fundamental characteristics of these cryogenic plasmas and cryoplasmas, and plasmas in supercritical fluids, especially supercritical fluid plasmas, are presented with their main applications. The research on such exotic plasmas is expected to lead to further understanding of plasma physics and, at the same time, enable new applications in various technological fields.
Expressions for linearized perturbations in ideal-fluid cosmological models
Ratra, B.
1988-01-01
We present closed-form solutions of the relativistic linear perturbation equations (in synchronous gauge) that govern the evolution of inhomogeneities in homogeneous, spatially flat, ideal-fluid, cosmological models. These expressions, which are valid for irregularities on any scale, allow one to analytically interpolate between the known approximate solutions which are valid at early times and at late times
Non-linear oscillations of fluid in a container
Verhagen, J.H.G.; van Wijngaarden, L.
1965-01-01
This paper is concerned with forced oscillations of fluid in a rectangular container. From the linearized approximation of the equations governing these oscillations, resonance frequencies are obtained for which the amplitude of the oscillations becomes infinite. Observation shows that under these
Geometry optimization of linear and annular plasma synthetic jet actuators
Neretti, G; Seri, P; Taglioli, M; Borghi, C A; Shaw, A; Iza, F
2017-01-01
The electrohydrodynamic (EHD) interaction induced in atmospheric air pressure by a surface dielectric barrier discharge (DBD) actuator has been experimentally investigated. Plasma synthetic jet actuators (PSJAs) are DBD actuators able to induce an air stream perpendicular to the actuator surface. These devices can be used in the field of aerodynamics to prevent or induce flow separation, modify the laminar to turbulent transition inside the boundary layer, and stabilize or mix air flows. They can also be used to enhance indirect plasma treatment effects, increasing the reactive species delivery rate onto surfaces and liquids. This can play a major role in plasma processing and chemical kinetics modelling, where often only diffusive mechanisms are considered. This paper reports on the importance that different electrode geometries can have on the performance of different PSJAs. A series of DBD aerodynamic actuators designed to produce perpendicular jets has been fabricated on two-layer printed circuit boards (PCBs). Both linear and annular geometries were considered, testing different upper electrode distances in the linear case and different diameters in the annular one. An AC voltage supplied at a peak of 11.5 kV and a frequency of 5 kHz was used. Lower electrodes were connected to the ground and buried in epoxy resin to avoid undesired plasma generation on the lower actuator surface. Voltage and current measurements were carried out to evaluate the active power delivered to the discharges. Schlieren imaging allowed the induced jets to be visualized and gave an estimate of their evolution and geometry. Pitot tube measurements were performed to obtain the velocity profiles of the PSJAs and to estimate the mechanical power delivered to the fluid. The optimal values of the inter-electrode distance and diameter were found in order to maximize jet velocity, mechanical power or efficiency. Annular geometries were found to achieve the best performance. (paper)
Exact solutions for a system of nonlinear plasma fluid equations
Prahovic, M.G.; Hazeltine, R.D.; Morrison, P.J.
1991-04-01
A method is presented for constructing exact solutions to a system of nonlinear plasma fluid equations that combines the physics of reduced magnetohydrodynamics and the electrostatic drift-wave description of the Charney-Hasegawa-Mima equation. The system has nonlinearities that take the form of Poisson brackets involving the fluid field variables. The method relies on modifying a class of simple equilibrium solutions, but no approximations are made. A distinguishing feature is that the original nonlinear problem is reduced to the solution of two linear partial differential equations, one fourth-order and the other first-order. The first-order equation has Hamiltonian characteristics and is easily integrated, supplying information about the general structure of solutions. 6 refs
The theory of hyrogenic plasmas and fluids
Dharma-Wardana, M.W.C.
1978-01-01
A comprehensive theory of the transverse dielectric function, light absorption and other aspects of photon propagation as well as level shifts, the chemical potential and statistical mechanics of hydrogenic fluids ranging from the fully ionized plasma to the atomic fluid, is presented. A coulomb basis is used instead of the usual plane waves for second quantization. The commutation rules for these operators are discussed and a simplification valid for electron-ion systems is considered. The Coulomb basis simplifies the theory by replacing the six interaction potentials involving atoms, ions and electrons by a single term. The free bound and photo processes also reduce to a single term. As in the best available theory of the uniform electron gas we have calculated the mass operator contained in the polarization operator of the photon Green function to second order and included a partial summation of higher order effects via a screening function. The shifted and broadened energy levels, the chemical potential and the modified Saha equation are obtained from the one-particle Green function. The complex refractive index, the absorption profile, etc. contain terms in first order thus easily recovering effects not recovered in the existing theories. In the fully ionized plasma limit the results lead to the usual Geldart and Taylor type Fermi gas response theory. In the atomic fluid limit the polarizable atom models of, for example, Bullough et al., are compared with our microscopic theory. Explicit algebraic expressions together with details of the evaluation of the matrix elements are given for the final results. (Auth.)
Approximate Riemann solver for the two-fluid plasma model
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
Nonlinear wave coupling in a warm plasma in the fluid
Malara, F.; Veltri, P.
1984-01-01
The general expression for nonlinear coupling between plasma modes is obtained. The nonlinear conductivity tensor is then calculated by means of the two-fluid plasma description taking into account the thermal pressure effects
Revisited global drift fluid model for linear devices
Reiser, Dirk
2012-01-01
The problem of energy conserving global drift fluid simulations is revisited. It is found that for the case of cylindrical plasmas in a homogenous magnetic field, a straightforward reformulation is possible avoiding simplifications leading to energetic inconsistencies. The particular new feature is the rigorous treatment of the polarisation drift by a generalization of the vorticity equation. The resulting set of model equations contains previous formulations as limiting cases and is suitable for efficient numerical techniques. Examples of applications on studies of plasma blobs and its impact on plasma target interaction are presented. The numerical studies focus on the appearance of plasma blobs and intermittent transport and its consequences on the release of sputtered target materials in the plasma. Intermittent expulsion of particles in radial direction can be observed and it is found that although the neutrals released from the target show strong fluctuations in their propagation into the plasma column, the overall effect on time averaged profiles is negligible for the conditions considered. In addition, the numerical simulations are utilised to perform an a-posteriori assessment of the magnitude of energetic inconsistencies in previously used simplified models. It is found that certain popular approximations, in particular by the use of simplified vorticity equations, do not significantly affect energetics. However, popular model simplifications with respect to parallel advection are found to provide significant deterioration of the model consistency.
Coherent vortex structures in fluids and plasmas
Tur, Anatoli
2017-01-01
This monograph introduces readers to the hydrodynamics of vortex formation, and reviews the last decade of active research in the field, offering a unique focus on research topics at the crossroads of traditional fluids and plasmas. Vortices are responsible for the process of macroscopic transport of momentum, energy and mass, and are formed as the result of spontaneous self-organization. Playing an important role in nature and technology, localized, coherent vortices are regularly observed in shear flows, submerged jets, afterbody flows and in atmospheric boundary layers, sometimes taking on the form of vortex streets. In addition, the book addresses a number of open issues, including but not limited to: which singularities are permitted in a 2D Euler equation besides point vortices? Which other, even more complex, localized vortices could be contained in the Euler equation? How do point vortices interact with potential waves?
Linear and nonlinear analysis of fluid slosh dampers
Sayar, B. A.; Baumgarten, J. R.
1982-11-01
A vibrating structure and a container partially filled with fluid are considered coupled in a free vibration mode. To simplify the mathematical analysis, a pendulum model to duplicate the fluid motion and a mass-spring dashpot representing the vibrating structure are used. The equations of motion are derived by Lagrange's energy approach and expressed in parametric form. For a wide range of parametric values the logarithmic decrements of the main system are calculated from theoretical and experimental response curves in the linear analysis. However, for the nonlinear analysis the theoretical and experimental response curves of the main system are compared. Theoretical predictions are justified by experimental observations with excellent agreement. It is concluded finally that for a proper selection of design parameters, containers partially filled with viscous fluids serve as good vibration dampers.
Linear and Nonlinear Electrostatic Waves in Unmagnetized Dusty Plasmas
Mamun, A. A.; Shukla, P. K.
2010-01-01
A rigorous and systematic theoretical study has been made of linear and nonlinear electrostatic waves propagating in unmagnetized dusty plasmas. The basic features of linear and nonlinear electrostatic waves (particularly, dust-ion-acoustic and dust-acoustic waves) for different space and laboratory dusty plasma conditions are described. The experimental observations of such linear and nonlinear features of dust-ion-acoustic and dust-acoustic waves are briefly discussed.
Exact collisional moments for plasma fluid theories
Pfefferle, David; Hirvijoki, Eero; Lingam, Manasvi
2017-10-01
The velocity-space moments of the often troublesome nonlinear Landau collision operator are expressed exactly in terms of multi-index Hermite-polynomial moments of the distribution functions. The collisional moments are shown to be generated by derivatives of two well-known functions, namely the Rosenbluth-MacDonald-Judd-Trubnikov potentials for a Gaussian distribution. The resulting formula has a nonlinear dependency on the relative mean flow of the colliding species normalised to the root-mean-square of the corresponding thermal velocities, and a bilinear dependency on densities and higher-order velocity moments of the distribution functions, with no restriction on temperature, flow or mass ratio of the species. The result can be applied to both the classic transport theory of plasmas, that relies on the Chapman-Enskog method, as well as to deriving collisional fluid equations that follow Grad's moment approach. As an illustrative example, we provide the collisional ten-moment equations with exact conservation laws for momentum- and energy-transfer rate.
Linear and nonlinear viscous flow in two-dimensional fluids
Gravina, D.; Ciccotti, G.; Holian, B.L.
1995-01-01
We report on molecular dynamics simulations of shear viscosity η of a dense two-dimensional fluid as a function of the shear rate γ. We find an analytic dependence of η on γ, and do not find any evidence whatsoever of divergence in the Green-Kubo (GK) value that would be caused by the well-known long-time tail for the shear-stress autocorrelation function, as predicted by the mode-coupling theory. In accordance with the linear response theory, the GK value of η agrees remarkably well with nonequilibrium values at small shear rates. (c) 1995 The American Physical Society
Linear birefringence and optical ativity in a magnetized plasma
Vuolo, J.H.; Galvao, R.M.O.
1982-02-01
Linear birefringence and optical activity are considered separately to electromagnetic wave propagation in magnetized cold plasma, using frequency approximation much bigger than plasma frequency. It's showen that in some interesting cases, those phenomena could be independents. Explicit expressions are obtained for refraction indices to linear birefringency and optical activity. The correspondents indices attenuation aRe obtained in first orden of attenuation. It's showen that the characteristic states for linear dichroism coincide with the characteristic states for linear birefringence. The characteristic states for elliptic dichroism are obtained. (M.A.F.) [pt
Indinavir Population Pharmacokinetics in Plasma and Cerebrospinal Fluid
Letendre, Scott L.; Capparelli, Edmund V.; Ellis, Ronald J.; McCutchan, J. Allen
2000-01-01
Plasma and cerebrospinal fluid (CSF) indinavir concentrations were measured by high-performance liquid chromatography. The median concentration in plasma exceeded that in CSF 10-fold. The modeled CSF curve was flat at 155 nM, and the estimated ratio of the areas under the CSF and plasma concentration-time curves was 6%. We conclude that CSF indinavir concentrations are lower than levels in plasma but exceed the clinical 95% inhibitory concentration range.
Nonlinear quantum fluid equations for a finite temperature Fermi plasma
Eliasson, Bengt; Shukla, Padma K
2008-01-01
Nonlinear quantum electron fluid equations are derived, taking into account the moments of the Wigner equation and by using the Fermi-Dirac equilibrium distribution for electrons with an arbitrary temperature. A simplified formalism with the assumptions of incompressibility of the distribution function is used to close the moments in velocity space. The nonlinear quantum diffraction effects into the fluid equations are incorporated. In the high-temperature limit, we retain the nonlinear fluid equations for a dense hot plasma and in the low-temperature limit, we retain the correct fluid equations for a fully degenerate plasma
The linear plasma generator Magnum-PSI
Eck, van H.J.N.
2013-01-01
The Dutch Institute for Fundamental Energy Research (DIFFER) has built the new experimental research facility Magnum-PSI. In Magnum-PSI, Plasma Surface Interaction (PSI) research for the nuclear fusion reactor ITER and reactors beyond ITER will be carried out. As such, it is essential that the
Kinematics of a Fluid Ellipse in a Linear Flow
Jonathan M. Lilly
2018-02-01
Full Text Available A four-parameter kinematic model for the position of a fluid parcel in a time-varying ellipse is introduced. For any ellipse advected by an arbitrary linear two-dimensional flow, the rates of change of the ellipse parameters are uniquely determined by the four parameters of the velocity gradient matrix, and vice versa. This result, termed ellipse/flow equivalence, provides a stronger version of the well-known result that a linear velocity field maps an ellipse into another ellipse. Moreover, ellipse/flow equivalence is shown to be a manifestation of Stokes’ theorem. This is done by deriving a matrix-valued extension of the classical Stokes’ theorem that involves a spatial integral over the velocity gradient tensor, thus accounting for the two strain terms in addition to the divergence and vorticity. General expressions for various physical properties of an elliptical ring of fluid are also derived. The ellipse kinetic energy is found to be composed of three portions, associated respectively with the circulation, the rate of change of the moment of inertia, and the variance of parcel angular velocity around the ellipse. A particular innovation is the use of four matrices, termed the I J K L basis, that greatly facilitate the required calculations.
Linear Vlasov plasma oscillations in the Fourier transformed velocity space
Sedláček, Zdeněk; Nocera, L.
2002-01-01
Roč. 296, - (2002), s. 117-124 ISSN 0375-9601 Institutional research plan: CEZ:AV0Z2043910 Keywords : linear Vlasov plasma Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.483, year: 2002
Physics through the 1990s: Plasmas and fluids
1986-01-01
This survey of plasma physics and fluid physics briefly describes present activities and recent major accomplishments. It also identifies research areas that are likely to lead to advances during the next decade. Plasma physics is divided into three major areas: general plasma physics, fusion plasma confinement and heating, and space and astrophysical plasmas. Fluid physics is treated as one topic, although it is an extremely diverse research field ranging from biological fluid dynamics to ship and aircraft performance to geological fluid dynamics. Subpanels, chosen for their technical expertise and scientific breadth, reviewed each of the four areas. The entire survey was coordinated and supervised by an Executive Committee, which is also responsible for the Executive Summary of this volume. Wherever possible, input from recent Advisory Committees was used, e.g., from the Magnetic Fusion Advisory Committee, the Space Science Board, and the Astronomy Survey Committee. This volume is organized as follows: An Introduction and Executive Summary that outlines (1) major findings and recommendations; (2) significant research accomplishments during the past decade and likely areas of future research emphasis; and (3) a brief summary of present funding levels, manpower resources, and institutional involvement; and the subpanel reports constitute Fluid Physics, General Plasma Physics, Fusion Plasma Confinement and Heating, and Space and Astrophysical Plasmas. An important conclusion of this survey is that both plasma physics and fluid physics are scientifically and intellectually well developed, and both ares are broad subdisciplines of physics. We therefore recommend that future physics surveys have separate volumes on the physics of plasmas and the physics of fluids
Extended fluid transport theory in the tokamak plasma edge
Stacey, W. M.
2017-06-01
Fluid theory expressions for the radial particle and energy fluxes and the radial distributions of pressure and temperature in the edge plasma are derived from fundamental conservation (particle, energy, momentum) relations, taking into account kinetic corrections arising from ion orbit loss, and integrated to illustrate the dependence of the observed edge pedestal profile structure on fueling, heating, and electromagnetic and thermodynamic forces. Solution procedures for the fluid plasma and associated neutral transport equations are discussed.
Ionization effects and linear stability in a coaxial plasma device
Kurt, Erol; Kurt, Hilal; Bayhan, Ulku
2009-03-01
A 2-D computer simulation of a coaxial plasma device depending on the conservation equations of electrons, ions and excited atoms together with the Poisson equation for a plasma gun is carried out. Some characteristics of the plasma focus device (PF) such as critical wave numbers a c and voltages U c in the cases of various pressures Pare estimated in order to satisfy the necessary conditions of traveling particle densities ( i.e. plasma patterns) via a linear analysis. Oscillatory solutions are characterized by a nonzero imaginary part of the growth rate Im ( σ) for all cases. The model also predicts the minimal voltage ranges of the system for certain pressure intervals.
Extreme hydrogen plasma densities achieved in a linear plasma generator
Rooij, van G.J.; Veremiyenko, V.P.; Goedheer, W.J.; Groot, de B.; Kleyn, A.W.; Smeets, P.H.M.; Versloot, T.W.; Whyte, D.G.; Engeln, R.A.H.; Schram, D.C.; Lopes Cardozo, N.J.
2007-01-01
A magnetized hydrogen plasma beam was generated with a cascaded arc, expanding in a vacuum vessel at an axial magnetic field of up to 1.6 T. Its characteristics were measured at a distance of 4 cm from the nozzle: up to a 2 cm beam diameter, 7.5×1020 m-3 electron density, ~2 eV electron and ion
Plasma heating by non-linear wave-Plasma interaction | Echi ...
We simulate the non-linear interaction of waves with magnetized tritium plasma with the aim of determining the parameter values that characterize the response of the plasma. The wave-plasma interaction has a non-conservative Hamiltonian description. The resulting system of Hamilton's equations is integrated numerically ...
Multi-fluid Approach to High-frequency Waves in Plasmas. III. Nonlinear Regime and Plasma Heating
Martínez-Gómez, David; Soler, Roberto; Terradas, Jaume
2018-03-01
The multi-fluid modeling of high-frequency waves in partially ionized plasmas has shown that the behavior of magnetohydrodynamic waves in the linear regime is heavily influenced by the collisional interaction between the different species that form the plasma. Here, we go beyond linear theory and study large-amplitude waves in partially ionized plasmas using a nonlinear multi-fluid code. It is known that in fully ionized plasmas, nonlinear Alfvén waves generate density and pressure perturbations. Those nonlinear effects are more pronounced for standing oscillations than for propagating waves. By means of numerical simulations and analytical approximations, we examine how the collisional interaction between ions and neutrals affects the nonlinear evolution. The friction due to collisions dissipates a fraction of the wave energy, which is transformed into heat and consequently raises the temperature of the plasma. As an application, we investigate frictional heating in a plasma with physical conditions akin to those in a quiescent solar prominence.
Linear and Nonlinear MHD Wave Processes in Plasmas. Final Report
Tataronis, J. A.
2004-01-01
This program treats theoretically low frequency linear and nonlinear wave processes in magnetized plasmas. A primary objective has been to evaluate the effectiveness of MHD waves to heat plasma and drive current in toroidal configurations. The research covers the following topics: (1) the existence and properties of the MHD continua in plasma equilibria without spatial symmetry; (2) low frequency nonresonant current drive and nonlinear Alfven wave effects; and (3) nonlinear electron acceleration by rf and random plasma waves. Results have contributed to the fundamental knowledge base of MHD activity in symmetric and asymmetric toroidal plasmas. Among the accomplishments of this research effort, the following are highlighted: Identification of the MHD continuum mode singularities in toroidal geometry. Derivation of a third order ordinary differential equation that governs nonlinear current drive in the singular layers of the Alfven continuum modes in axisymmetric toroidal geometry. Bounded solutions of this ODE implies a net average current parallel to the toroidal equilibrium magnetic field. Discovery of a new unstable continuum of the linearized MHD equation in axially periodic circular plasma cylinders with shear and incompressibility. This continuum, which we named ''accumulation continuum'' and which is related to ballooning modes, arises as discrete unstable eigenfrequency accumulate on the imaginary frequency axis in the limit of large mode numbers. Development of techniques to control nonlinear electron acceleration through the action of multiple coherent and random plasmas waves. Two important elements of this program aye student participation and student training in plasma theory
Laboratory beam-plasma interactions: linear and nonlinear
Christiansen, P.J.; Jain, V.K.; Bond, J.W.
1982-01-01
The present investigation is concerned with the configuration of a cool plasma (often magnetized axially) penetrated by an injected electron beam. The attempt is made to demonstrate that despite unavoidable scaling limitations, laboratory experiments can illuminate, in a controlled fashion, details of beam plasma interaction processes in a way which will never be possible in the space plasma physics. In view of the increasing interest in high frequency instabilities in the auroral zone, the possibilities for interesting cross fertilizations of the two fields appear to be extensive. The linear theory is considered along with low frequency couplings and indirect effects. Attention is given to the evidence for the existence of exponentially growing instabilities in beam plasma interactions. The consequences of such instabilities are also explored and some processes of nonlinear processes are discussed, taking into account quasi-linear effects, trapping effects, nonlinear effects, trapping effects, nonlinear wave-wave interactions, and self-modulation and cavitation. 80 references
Intrinsic suppression of turbulence in linear plasma devices
Leddy, J.; Dudson, B.
2017-12-01
Plasma turbulence is the dominant transport mechanism for heat and particles in magnetised plasmas in linear devices and tokamaks, so the study of turbulence is important in limiting and controlling this transport. Linear devices provide an axial magnetic field that serves to confine a plasma in cylindrical geometry as it travels along the magnetic field from the source to the strike point. Due to perpendicular transport, the plasma density and temperature have a roughly Gaussian radial profile with gradients that drive instabilities, such as resistive drift-waves and Kelvin-Helmholtz. If unstable, these instabilities cause perturbations to grow resulting in saturated turbulence, increasing the cross-field transport of heat and particles. When the plasma emerges from the source, there is a time, {τ }\\parallel , that describes the lifetime of the plasma based on parallel velocity and length of the device. As the plasma moves down the device, it also moves azimuthally according to E × B and diamagnetic velocities. There is a balance point in these parallel and perpendicular times that sets the stabilisation threshold. We simulate plasmas with a variety of parallel lengths and magnetic fields to vary the parallel and perpendicular lifetimes, respectively, and find that there is a clear correlation between the saturated RMS density perturbation level and the balance between these lifetimes. The threshold of marginal stability is seen to exist where {τ }\\parallel ≈ 11{τ }\\perp . This is also associated with the product {τ }\\parallel {γ }* , where {γ }* is the drift-wave linear growth rate, indicating that the instability must exist for roughly 100 times the growth time for the instability to enter the nonlinear growth phase. We explore the root of this correlation and the implications for linear device design.
Three-fluid magnetohydrodynamical simulation of plasma focus discharges
Behler, K.; Bruhns, H.
1987-01-01
A two-dimensional, three-fluid code based on the two-fluid Potter code [Methods in Computational Physics (Academic, New York, 1970), Vol. 9, p. 340] was developed for simulating the plasma focus discharge. With this code it is possible to treat the neutral gas in addition to the plasma components and to model the ionization and recombination phenomena. Thus the sheet dynamics in a plasma focus can be studied and effects investigated such as the occurrence of residual gas (or plasma) density behind the current sheet in the run-down phase. This is a prerequisite to the occurrence of leak currents, which are one of the causes limiting the performance of large plasma focus devices. It is shown that fast operating foci with small dimensions behave favorably compared with the ''classical'' Mather focus [Methods of Experimental Physics (Academic, New York, 1971), Vol. 9B, p. 187] with long coaxial electrodes
ALFVEN WAVES IN A PARTIALLY IONIZED TWO-FLUID PLASMA
Soler, R.; Ballester, J. L.; Terradas, J. [Departament de Fisica, Universitat de les Illes Balears, E-07122 Palma de Mallorca (Spain); Carbonell, M., E-mail: roberto.soler@uib.es, E-mail: joseluis.ballester@uib.es, E-mail: jaume.terradas@uib.es, E-mail: marc.carbonell@uib.es [Departament de Matematiques i Informatica, Universitat de les Illes Balears, E-07122 Palma de Mallorca (Spain)
2013-04-20
Alfven waves are a particular class of magnetohydrodynamic waves relevant in many astrophysical and laboratory plasmas. In partially ionized plasmas the dynamics of Alfven waves is affected by the interaction between ionized and neutral species. Here we study Alfven waves in a partially ionized plasma from the theoretical point of view using the two-fluid description. We consider that the plasma is composed of an ion-electron fluid and a neutral fluid, which interact by means of particle collisions. To keep our investigation as general as possible, we take the neutral-ion collision frequency and the ionization degree as free parameters. First, we perform a normal mode analysis. We find the modification due to neutral-ion collisions of the wave frequencies and study the temporal and spatial attenuation of the waves. In addition, we discuss the presence of cutoff values of the wavelength that constrain the existence of oscillatory standing waves in weakly ionized plasmas. Later, we go beyond the normal mode approach and solve the initial-value problem in order to study the time-dependent evolution of the wave perturbations in the two fluids. An application to Alfven waves in the low solar atmospheric plasma is performed and the implication of partial ionization for the energy flux is discussed.
Two-fluid and parallel compressibility effects in tokamak plasmas
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
Non-linear collective phenomena in dusty plasmas
Tsytovich, V N; Morfill, G E
2004-01-01
Dusty plasmas are unusual states of matter where the interactions between the dust grains can be collective and are not a sum of all pair particle interactions. This state of matter is appropriate to form non-linear dissipative collective self-organized structures. It is found that the potential around the grains can be over-screened leading to a new phenomenon-collective attraction of pairs of large charge grains of equal sign. The grain clouds can self-contract and their collapse is terminated at distances where the interaction becomes repulsive. The homogeneous dusty plasma distribution is universally unstable to form structures. The potential of the collective attraction is proportional to the square of the dimensionless parameter P = n d Z d /n i , where n d and n i are the average dust and ion densities, respectively, and Z d is the dust charge in units of electron charge. The collective attraction is determined by finite grain size and by the presence of absorption of plasma flux on grains. The physics of attraction is related to the space charge accumulation caused by collective flux disturbances. The collective attraction operates for systems with size larger than the mean free path for ion-dust absorption, the condition met in many existing low temperature dusty plasma experiments, in edge plasmas of fusion devices and in space dusty plasmas. The collective attraction exceeds the previously known non-collective attraction such as shadow attraction or wake attraction. The collective attraction can be responsible for pairing of dust grains (this process is completely classical in contrast to the known pairing in superconductivity) and can serve as the main process for the formation of more complicated dust complexes up to dust-plasma crystals. The equilibrium structures formed by collective attraction have universal properties and can exist in a limited domain of parameters (similar to the equilibrium balance known for stars). The balance conditions for
Fluid-structure interactions in one-dimensional linear cases
Schumann, U.
1979-01-01
The interaction of pressure waves in a pipe with an elastic endwall (piston) is analyzed using a linear ('acoustic') model. Two transient and two periodic cases are investigated. In the transient cases the motions are initiated by either a sudden pressure drop at the opeen end (breaking membrane) or by a sudden release of the piston from a non-equilibrium position ('snapback'); in the latter case the other end of the pipe is closed. In the periodic cases harmonic oscillations of the piston and the fluid are investigated with the other end of the pipe being either closed or open (kept at constant pressure). The problem is characterized by three non-dimensional numbers (e.g.: Mach-, Strouhal-, and an interaction-number). The solution of the wave equation for the pressure accounting for the coupling to the structure can be reduced analytically to the problem of integrating one ordinary differential equation of second order in time. This differential equation in turn can be integrated analytically at least for a certain time period. At later times this ordinary differential equation is integrated numerically. For the periodic cases eigenvalue-problems arise with an infinite number of solutions. The first few eigensolutions are given. (orig./RW) [de
Linear theory of plasma filled backward wave oscillator
An analytical and numerical study of backward wave oscillator (BWO) in linear regime is presented to get an insight into the excitation of electromagnetic waves as a result of the interaction of the relativistic electron beam with a slow wave structure. The effect of background plasma on the BWO instability is also presented.
Linear Plasma Oscillation Described by Superposition of Normal Modes
Pécseli, Hans
1974-01-01
The existence of steady‐state solutions to the linearized ion and electron Vlasov equation is demonstrated for longitudinal waves in an initially stable plasma. The evolution of an arbitrary initial perturbation can be described by superposition of these solutions. Some common approximations...
Linear theory of plasma Čerenkov masers
Birau, M.
1996-11-01
A different theoretical model of Čerenkov instability in the linear amplification regime of plasma Čerenkov masers is developed. The model assumes a cold relativistic annular electron beam propagating through a column of cold dense plasma, the two bodies being immersed in an infinite magnetic guiding field inside a perfect cylindrical waveguide. In order to simplify the calculations, a radial rectangular distribution of plasma and beam density is assumed and only azimuthal symmetric modes are under investigation. The model's difference consists of taking into account the whole plasma and beam electromagnetic structures in the interpretation of the Čerenkov instability. This model leads to alternative results such as the possibility of emission at several frequencies. In addition, the electric field is calculated taking into account its radial phase dependence, so that a map of the field in the interaction region can be presented.
Transport of high fluxes of hydrogen plasma in a linear plasma generator
Vijvers, W.A.J.; Al, R.S.; Lopes Cardozo, N.J.; Goedheer, W.J.; Groot, de B.; Kleyn, A.W.; Meiden, van der H.J.; Peppel, van de R.J.E.; Schram, D.C.; Shumack, A.E.; Westerhout, J.; Rooij, van G.J.; Schmidt, J.; Simek, M.; Pekarek, S.; Prukner, V.
2007-01-01
A study was made to quantify the losses during the convective hydrogen plasma transport in the linear plasma generator Pilot-PSI due to volume recombination. A transport efficiency of 35% was achieved at neutral background pressures below ~7 Pa in a magnetic field of 1.2 T. This efficiency decreased
A steady-state fluid model of the coaxial plasma gun
Herziger, G.; Krompholz, H.; Schneider, W.; Schoenbach, K.
1979-01-01
The plasma layer in a coaxial plasma gun is considered as a shock front driven by expanding magnetic fields. Analytical steady-state solutions of the fluid equations yield the plasma properties, allowing the scaling of plasma focus devices. (Auth.)
Fluid aspects of electron streaming instability in electron-ion plasmas
Jao, C.-S.; Hau, L.-N.
2014-01-01
Electrons streaming in a background electron and ion plasma may lead to the formation of electrostatic solitary wave (ESW) and hole structure which have been observed in various space plasma environments. Past studies on the formation of ESW are mostly based on the particle simulations due to the necessity of incorporating particle's trapping effects. In this study, the fluid aspects and thermodynamics of streaming instabilities in electron-ion plasmas including bi-streaming and bump-on-tail instabilities are addressed based on the comparison between fluid theory and the results from particle-in-cell simulations. The energy closure adopted in the fluid model is the polytropic law of d(pρ −γ )/dt=0 with γ being a free parameter. Two unstable modes are identified for the bump-on-tail instability and the growth rates as well as the dispersion relation of the streaming instabilities derived from the linear theory are found to be in good agreement with the particle simulations for both bi-streaming and bump-on-tail instabilities. At the nonlinear saturation, 70% of the electrons are trapped inside the potential well for the drift velocity being 20 times of the thermal velocity and the pρ −γ value is significantly increased. Effects of ion to electron mass ratio on the linear fluid theory and nonlinear simulations are also examined
The development of plasma lenses for linear colliders
Norem, J.; Cole, B.; Gai, W.
1989-01-01
The plasma lens, first proposed by Chen, can in principle raise the luminosity of a linear collider with minimal interaction with the accelerator systems, nevertheless the short focal length lens design does interact strongly with the design of the particle detector at the interaction point. We have thus considered a of number options for using the lens and have begun to test plasma focusing experimentally. This paper briefly reviews constraints on use of the lens and its proposed operating modes, and then describes tests of a prototype valve/nozzle system and experimental tests of focusing. 10 refs., 3 figs
Implicit multi-fluid simulation of interpenetrating plasmas
Rambo, P.W.; Denavit, J.
1992-01-01
A one dimensional simulation code for interpenetrating multi-component plasmas is presented. Separate fluid equations for multiple species and the Poisson equation for the electric field are solved implicitly to allow stable accurate solutions over a wide range of the time scale parameters ω p Δt and ν c Δt (ω p is the plasma frequency, ν c a typical collision frequency and Δt the time step). In regions where ω p Δt c Δt p Δt >>1 and/or ν c Δt>>1, the ambipolar and/or diffusion models are recovered. In regions of low collisionality, particles may be created and deleted which are followed using particle and cell techniques combined with scatter and drag due to collisions with the fluids. Applications of this code to interpenetrating laser generated plasmas are presented
Linear relativistic gyrokinetic equation in general magnetically confined plasmas
Tsai, S.T.; Van Dam, J.W.; Chen, L.
1983-08-01
The gyrokinetic formalism for linear electromagnetic waves of arbitrary frequency in general magnetic-field configurations is extended to include full relativistic effects. The derivation employs the small adiabaticity parameter rho/L 0 where rho is the Larmor radius and L 0 the equilibrium scale length. The effects of the plasma and magnetic field inhomogeneities and finite Larmor-radii effects are also contained
Two-dimensional convection and interchange motions in fluids and magnetized plasmas
Garcia, O.E.; Bian, N.H.; Naulin, V.
2006-01-01
fluids, emphasizing its relation to interchange motions of non- uniformly magnetized plasmas. This is followed by a review of the theories for the onset of convection and quasi-linear saturation in driven-dissipative systems. Non-linear numerical simulations which result in stationary convective states...... behaviour of the fluctuation level which is associated with relaxation oscillations in the kinetic energy of the azimuthally mean flows. This leads to a state of large-scale intermittency manifested by exponential tails in the single-point probability distribution function of the dependent variables...
Sotnikov, V.I.; Paraschiv, I.; Makhin, V.; Bauer, B.S.; Leboeuf, J.N.; Dawson, J.M.
2002-01-01
A systematic study of the linear stage of sheared flow stabilization of Z-pinch plasmas based on the Hall fluid model with equilibrium that contains sheared flow and an axial magnetic field is presented. In the study we begin with the derivation of a general set of equations that permits the evaluation of the combined effect of sheared flow and axial magnetic field on the development of the azimuthal mode number m=0 sausage and m=1 kink magnetohydrodynamic (MHD) instabilities, with the Hall term included in the model. The incorporation of sheared flow, axial magnetic field, and the Hall term allows the Z-pinch system to be taken away from the region in parameter space where ideal MHD is applicable to a regime where nonideal effects tend to govern stability. The problem is then treated numerically by following the linear development in time of an initial perturbation. The numerical results for linear growth rates as a function of axial sheared flow, an axial magnetic field, and the Hall term are reported
Lim, Jong Hyeuk; Kim, Kyong Nam; Park, Jung Kyun; Yeom, Geun Young
2008-01-01
This study examined the effect of the antenna capacitance of an inductively coupled plasma (ICP) source, which was varied using an internal linear antenna, on the electrical and plasma characteristics of the ICP source. The inductive coupling at a given rf current increased with decreasing antenna capacitance. This was caused by a decrease in the inner copper diameter of the antenna made from coaxial copper/quartz tubing, which resulted in a higher plasma density and lower plasma potential. By decreasing the diameter of the copper tube from 25 to 10 mm, the plasma density of a plasma source size of 2750x2350 mm 2 was increased from approximately 8x10 10 /cm 3 to 1.5x10 11 /cm 3 at 15 mTorr Ar and 9 kW of rf power
Fluid description of multi-component solar partially ionized plasma
Khomenko, E.; Collados, M.; Vitas, N.; Díaz, A.
2014-01-01
We derive self-consistent formalism for the description of multi-component partially ionized solar plasma, by means of the coupled equations for the charged and neutral components for an arbitrary number of chemical species, and the radiation field. All approximations and assumptions are carefully considered. Generalized Ohm's law is derived for the single-fluid and two-fluid formalism. Our approach is analytical with some order-of-magnitude support calculations. After general equations are developed, we particularize to some frequently considered cases as for the interaction of matter and radiation
Lagrangians for plasmas in drift-fluid approximation
Pfirsch, D.; Correa-Restrepo, D.
1996-10-01
For drift waves and related instabilities conservation laws can play a crucial role. In an ideal theory these conservation laws are guaranteed when a Lagrangian can be found from which the equations for the various quantities result by Hamilton's principle. Such a Lagrangian for plasmas in drift-fluid approximation was obtained by a heuristic method in a recent paper by Pfirsch and Correa-Restrepo. In the present paper the same Lagrangian is derived from the exact multi-fluid Lagrangian via an iterative approximation procedure which resembles the standard method usually applied to the equations of motion. That method, however, does not guarantee all the conservation laws to hold. (orig.)
Potocký, Štěpán; Babchenko, Oleg; Davydova, Marina; Ižák, Tibor; Čada, Martin; Kromka, Alexander
2014-01-01
Roč. 53, č. 5 (2014), "05FP04-1"-"05FP04-3" ISSN 0021-4922 R&D Projects: GA TA ČR TA01011740; GA ČR GAP205/12/0908 Grant - others:AVČR(CZ) M100100902 Institutional support: RVO:68378271 Keywords : antenna linear * CVD system * plasma Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.127, year: 2014
A plasma polymerization technique to overcome cerebrospinal fluid shunt infections
Coekeliler, D [Plasma Aided Bioengineering and Biotechnology Research Laboratory, Engineering Faculty, Hacettepe University, 06532, Ankara (Turkey); Caner, H [Department of Neurosurgery, School of Medicine, Baskent University, 06610, Ankara (Turkey); Zemek, J [Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnicka 10, 162 53, Prague, Czech Republic (Czech Republic); Choukourov, A [Department of Macromolecular Physics, Charles University, V Holesovickach 2, 18000 Prague (Czech Republic); Biederman, H [Department of Macromolecular Physics, Charles University, V Holesovickach 2, 18000 Prague (Czech Republic); Mutlu, M [Plasma Aided Bioengineering and Biotechnology Research Laboratory, Engineering Faculty, Hacettepe University, 06532, Ankara (Turkey)
2007-03-01
Prosthetic devices, mainly shunts, are frequently used for temporary or permanent drainage of cerebrospinal fluid. The pathogenesis of shunt infection is a very important problem in modern medicine and generally this is characterized by staphylococcal adhesion to the cerebrospinal fluid shunt surfaces. In this paper, the prevention of the attachment of test microorganism Staphylococcus epidermidis on the cerebrospinal fluid shunt surfaces by 2-hydroxyethylmethacrylate (HEMA) precursor modification in the plasma polymerization system, is reported. Different plasma polymerization conditions (RF discharge power 10-20-30 W, exposure time 5-10-15 min) were employed during the surface modification. The surface chemistry and topology of unmodified and modified shunts was characterized by x-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and atomic force microscopy (AFM). Also, static contact angle measurements were performed to state the change of surface hydrophilicity. All samples were tested in vitro with Staphylococcus epidermidis. A plasma-polymerized HEMA film (PP HEMA) was found to be an alternative simple method to decrease the microorganism attachment and create bacterial anti-fouling surfaces. The attachment of the model microorganism Staphylococcus epidermidis on the shunt surface modified by PP HEMA at 20 W and 15 min was reduced 62.3% if compared to the unmodified control surface of the shunt.
Four-fluid description of turbulent plasma focus dynamics
Hayd, A.; Maurer, M.; Meinke, P.; Kaeppeler, H.J.
1984-06-01
The dynamic phenomena in the compression, pinch and late phases of the plasma focus experiment POSEIDON in its operational mode at 60 kV, 280 kJ, were previously calculated from a two-fluid theory using the new hybrid code REDUCE/FORTRAN. Two important results were found: the neutron production already in the pinch phase for currents larger than 500 kA and filamentary structures on and around the pinch axis. In a continuation of this work, a four-fluid system of dynamical equations was formulated and programmed with the REDUCE/FORTRAN code. Besides macro-turbulence, the new four-fluid theory includes micro-instabilities and anomalous transport properties, as well as the runaway effect for electrons and ions. First results from calculations with this new theory are presented and are compared with previous calculations and with recent experimental observations. (orig.)
Spectrum of a linear antenna in a cold magnetized plasma
Eldridge, O.; Kritz, A.H.
1975-04-01
The fields radiated by a linear antenna in a cold magnetized plasma are calculated. The principal results are expressed in the input impedance and power spectrum of the near field, expressed as a function of the wavenumber or index of refraction parallel to the field. For frequencies below the electron plasma frequency and above the lower hybrid frequency the spectrum shows a broad maximum for short parallel wavelengths. The parallel index of refraction at this maximum is approximately the ratio of free space wavelength to antenna length. A spectrum of this sort is required by the accessibility conditions for heating at the lower hybrid resonance from a wave launched in a region of lower density. The impedance of a short antenna in this region is capacitive and a few hundred ohms in magnitude. (U.S.)
Bhakta, S.; Prajapati, R. P.; Dolai, B.
2017-08-01
The small amplitude quantum magnetohydrodynamic (QMHD) waves and linear firehose and mirror instabilities in uniformly rotating dense quantum plasma have been investigated using generalized polytropic pressure laws. The QMHD model and Chew-Goldberger-Low (CGL) set of equations are used to formulate the basic equations of the problem. The general dispersion relation is derived using normal mode analysis which is discussed in parallel, transverse, and oblique wave propagations. The fast, slow, and intermediate QMHD wave modes and linear firehose and mirror instabilities are analyzed for isotropic MHD and CGL quantum fluid plasmas. The firehose instability remains unaffected while the mirror instability is modified by polytropic exponents and quantum diffraction parameter. The graphical illustrations show that quantum corrections have a stabilizing influence on the mirror instability. The presence of uniform rotation stabilizes while quantum corrections destabilize the growth rate of the system. It is also observed that the growth rate stabilizes much faster in parallel wave propagation in comparison to the transverse mode of propagation. The quantum corrections and polytropic exponents also modify the pseudo-MHD and reverse-MHD modes in dense quantum plasma. The phase speed (Friedrichs) diagrams of slow, fast, and intermediate wave modes are illustrated for isotropic MHD and double adiabatic MHD or CGL quantum plasmas, where the significant role of magnetic field and quantum diffraction parameters on the phase speed is observed.
Rayleigh Taylor instability of two superposed compressible fluids in un-magnetized plasma
Sharma, P K; Tiwari, A; Argal, S; Chhajlani, R K
2014-01-01
The linear Rayleigh Taylor instability of two superposed compressible Newtonian fluids is discussed with the effect of surface tension which can play important roles in space plasma. As in both the superposed Newtonian fluids, the system is stable for potentially stable case and unstable for potentially unstable case in the present problem also. The equations of the problem are solved by normal mode method and a dispersion relation is obtained for such a system. The behaviour of growth rate is examined in the presence of surface tension and it is found that the surface tension has stabilizing influence on the Rayleigh Taylor instability of two superposed compressible fluids. Numerical analysis is performed to show the effect of sound velocity and surface tension on the growth rate of Rayleigh Taylor instability. It is found that both parameters have stabilizing influence on the growth rate of Rayleigh Taylor instability.
Computer simulation of plasma behavior in open-ended linear theta machines. Scientific report 81-5
Stover, E. K.
1981-04-01
Zero-dimensional and one-dimensional fluid plasma computer models have been developed to study the behavior of linear theta pinch plasmas. Computer simulation results generated from these codes are compared with data obtained from two theta pinch experiments so that significant machine plasma behavior can be identified. The experiments examined are a collisional experiment, T/sub i/ approx. 50 eV, n/sub e/ approx. 10/sup 17/ cm/sup -3/, where the plasma mean-free-path was significantly less than the plasma column length, and a hot ion species experiment, T/sub i/ approx. 3 keV, n/sub e/ approx. 10/sup 16/ cm/sup -3/, where the ion mean-free-path was on the order of the plasma column length.
Computer simulation of plasma behavior in open-ended linear theta machines. Scientific report 81-5
Stover, E.K.
1981-04-01
Zero-dimensional and one-dimensional fluid plasma computer models have been developed to study the behavior of linear theta pinch plasmas. Computer simulation results generated from these codes are compared with data obtained from two theta pinch experiments so that significant machine plasma behavior can be identified. The experiments examined are a collisional experiment, T/sub i/ approx. 50 eV, n/sub e/ approx. 10 17 cm -3 , where the plasma mean-free-path was significantly less than the plasma column length, and a hot ion species experiment, T/sub i/ approx. 3 keV, n/sub e/ approx. 10 16 cm -3 , where the ion mean-free-path was on the order of the plasma column length
Linear kinetic enlightenment of a slab of nonuniform plasma
Revenchuk, S.M.
1996-01-01
A phenomenon of linear kinetic regeneration of a harmonic electric-field perturbation beyond the nonuniform opacity barrier due to electrons trapped by a potential well is investigated. Such electrons are reflected by the well walls without loss of phase memory about the external perturbation, which is rehabilitated on the other side of the barrier. The incidence of the electromagnetic wave polarized in the plane of incidence on a plasma slab. Analytic expressions for the regenerated electric field and regeneration coefficient are obtained in the ballistic approximation. The dependence of the regeneration coefficient on shape of the electrostatic potential confining the wave barrier is discussed
Fluid model of inductively coupled plasma etcher based on COMSOL
Cheng Jia; Ji Linhong; Zhu Yu; Shi Yixiang
2010-01-01
Fluid dynamic models are generally appropriate for the investigation of inductively coupled plasmas. A commercial ICP etcher filled with argon plasma is simulated in this study. The simulation is based on a multiphysical software, COMSOL(TM), which is a partial differential equation solver. Just as with other plasma fluid models, there are drift-diffusion approximations for ions, the quasi-neutrality assumption for electrons movements, reduced Maxwell equations for electromagnetic fields, electron energy equations for electron temperatures and the Navier-Stokes equation for neutral background gas. The two-dimensional distribution of plasma parameters are shown at 200 W of power and 1.33 Pa (10 mTorr) of pressure. Then the profile comparison of the electron number density and temperature with respect to power is illustrated. Finally we believe that there might be some disagreement between the predicted values and the real ones, and the reasons for this difference would be the Maxwellian eedf assumption and the lack of the cross sections of collisions and the reaction rates. (semiconductor physics)
Three-wave scattering in magnetized plasmas: From cold fluid to quantized Lagrangian.
Shi, Yuan; Qin, Hong; Fisch, Nathaniel J
2017-08-01
Large amplitude waves in magnetized plasmas, generated either by external pumps or internal instabilities, can scatter via three-wave interactions. While three-wave scattering is well known in collimated geometry, what happens when waves propagate at angles with one another in magnetized plasmas remains largely unknown, mainly due to the analytical difficulty of this problem. In this paper, we overcome this analytical difficulty and find a convenient formula for three-wave coupling coefficient in cold, uniform, magnetized, and collisionless plasmas in the most general geometry. This is achieved by systematically solving the fluid-Maxwell model to second order using a multiscale perturbative expansion. The general formula for the coupling coefficient becomes transparent when we reformulate it as the scattering matrix element of a quantized Lagrangian. Using the quantized Lagrangian, it is possible to bypass the perturbative solution and directly obtain the nonlinear coupling coefficient from the linear response of the plasma. To illustrate how to evaluate the cold coupling coefficient, we give a set of examples where the participating waves are either quasitransverse or quasilongitudinal. In these examples, we determine the angular dependence of three-wave scattering, and demonstrate that backscattering is not necessarily the strongest scattering channel in magnetized plasmas, in contrast to what happens in unmagnetized plasmas. Our approach gives a more complete picture, beyond the simple collimated geometry, of how injected waves can decay in magnetic confinement devices, as well as how lasers can be scattered in magnetized plasma targets.
Non-linear magnetohydrodynamic modeling of plasma response to resonant magnetic perturbations
Orain, F.; Bécoulet, M.; Dif-Pradalier, G.; Nardon, E.; Passeron, C.; Latu, G.; Grandgirard, V.; Fil, A.; Ratnani, A. [CEA, IRFM, F-13108 Saint-Paul-Lez-Durance (France); Huijsmans, G. [ITER Organization, Route de Vinon, F-13115 Saint-Paul-Lez-Durance (France); Pamela, S. [IIFS-PIIM. Aix Marseille Université - CNRS, 13397 Marseille Cedex20 (France); Chapman, I.; Kirk, A.; Thornton, A. [EURATOM/CCFE Fusion Association, Culham Science Centre, Oxon OX14 3DB (United Kingdom); Hoelzl, M. [Max-Planck-Institut für Plasmaphysik, EURATOM Association, Garching (Germany); Cahyna, P. [Association EURATOM/IPP.CR, Prague (Czech Republic)
2013-10-15
The interaction of static Resonant Magnetic Perturbations (RMPs) with the plasma flows is modeled in toroidal geometry, using the non-linear resistive MHD code JOREK, which includes the X-point and the scrape-off-layer. Two-fluid diamagnetic effects, the neoclassical poloidal friction and a source of toroidal rotation are introduced in the model to describe realistic plasma flows. RMP penetration is studied taking self-consistently into account the effects of these flows and the radial electric field evolution. JET-like, MAST, and ITER parameters are used in modeling. For JET-like parameters, three regimes of plasma response are found depending on the plasma resistivity and the diamagnetic rotation: at high resistivity and slow rotation, the islands generated by the RMPs at the edge resonant surfaces rotate in the ion diamagnetic direction and their size oscillates. At faster rotation, the generated islands are static and are more screened by the plasma. An intermediate regime with static islands which slightly oscillate is found at lower resistivity. In ITER simulations, the RMPs generate static islands, which forms an ergodic layer at the very edge (ψ≥0.96) characterized by lobe structures near the X-point and results in a small strike point splitting on the divertor targets. In MAST Double Null Divertor geometry, lobes are also found near the X-point and the 3D-deformation of the density and temperature profiles is observed.
Two-fluid static spherical configurations with linear mass function in the Einstein-Cartan theory
Gallakhmetov, A.M.
2002-01-01
In the framework of the Einstein-Cartan theory, two-fluid static spherical configurations with linear mass function are considered. One of these modelling anisotropic matter distributions within star and the other fluid is a perfect fluid representing a source of torsion. It is shown that the solutions of the Einstein equations for anisotropic relativistic spheres in General Relativity may generate the solutions in the Einstein-Cartan theory. Some exact solutions are obtained
Linear waves in two-fluid relativistic gasdynamics
Gavrikov, M.B.; Solov'ev, L.S.
1988-01-01
This paper is devoted to the development of a theory of waves propagating in a two-component gaseous medium. In all cases considered the authors use only the method of two-fluid relativistic electromagnetic gasdynamics in the framework of the special relativity theory. They pay special attention to the problem of the interaction in a mixture of both neutral and charged gases when they move relative to one another. This interaction is for charged gases responsible for the appearance of ohmic resistance to an electrical current
Dispersion of linearly polarized electromagnetic wave in magnetized quantum plasma
Singh, Abhisek Kumar; Kumar, Punit
2015-01-01
The generation of harmonic radiation is significant in terms of laser-plasma interaction and has brought interesting notice due to the diversity of its applications. The odd harmonics of laser frequency are generated in the majority of laser interactions with homogenous plasma. It has been remarked that second harmonic generation takes place in the presence of density gradient which gives rise to perturbation in the electron density at the laser frequency. The density perturbation coupled with the quiver motion of the electrons produces a source current at the second harmonic frequency. Second harmonic generation has also been related with filamentation. In the present paper, a study of second harmonic generation by propagation of a linearly polarized electromagnetic wave through homogeneous high density quantum plasma in the presence of transverse magnetic field. The nonlinear current density and dispersion relations for the fundamental and second harmonic frequencies have been obtained using the recently developed quantum hydrodynamic (QHD) model. The effect of quantum Bohm potential, Fermi pressure and the electron spin have been taken into account. The second harmonic is found to be less dispersed than the first. (author)
APS presents prizes in fluid dynamics and plasma physics
Anon.
1992-01-01
This article reviews the presentation of the American Physical Society awards in fluid dynamics and plasma physics. The recipient of the plasma physics James Clerk Maxwell Prize was John M. Green for contributions to the theory of magnetohydrodynamics equilibria and ideal and resistive instabilities, for discovering the inverse scattering transform leading to soliton solutions of many nonlinear partial differential equations and for inventing the residue method of determining the transition to global chaos. The excellence in Plasma Physics Research Award was presented to Nathaniel A. Fisch for theoretical investigations of noninductive current generation in toroidally confined plasma. Wim Pieter Leemans received the Simon Ramo Award for experimental and simulational contributions to laser-plasma physics. William R. Sears was given the 1992 Fuid Dynamics Prize for contributions to the study of steady and unsteady aerodynamics, aeroacoustics, magnetoaerodynamics,and wind tunnel design. William C. Reynolds received the Otto Laporte Award for experimental, theoretical, and computational work in turbulence modeling and control and leadership in direct numerical simulation and large eddy simulation
MAGNETOACOUSTIC WAVES IN A PARTIALLY IONIZED TWO-FLUID PLASMA
Soler, Roberto; Ballester, Jose Luis [Departament de Física, Universitat de les Illes Balears, E-07122 Palma de Mallorca (Spain); Carbonell, Marc, E-mail: roberto.soler@uib.es, E-mail: joseluis.ballester@uib.es, E-mail: marc.carbonell@uib.es [Departament de Matemàtiques i Informàtica, Universitat de les Illes Balears, E-07122 Palma de Mallorca (Spain)
2013-11-01
Compressible disturbances propagate in a plasma in the form of magnetoacoustic waves driven by both gas pressure and magnetic forces. In partially ionized plasmas the dynamics of ionized and neutral species are coupled due to ion-neutral collisions. As a consequence, magnetoacoustic waves propagating through a partially ionized medium are affected by ion-neutral coupling. The degree to which the behavior of the classic waves is modified depends on the physical properties of the various species and on the relative value of the wave frequency compared to the ion-neutral collision frequency. Here, we perform a comprehensive theoretical investigation of magnetoacoustic wave propagation in a partially ionized plasma using the two-fluid formalism. We consider an extensive range of values for the collision frequency, ionization ratio, and plasma β, so that the results are applicable to a wide variety of astrophysical plasmas. We determine the modification of the wave frequencies and study the frictional damping due to ion-neutral collisions. Approximate analytic expressions for the frequencies are given in the limit case of strongly coupled ions and neutrals, while numerically obtained dispersion diagrams are provided for arbitrary collision frequencies. In addition, we discuss the presence of cutoffs in the dispersion diagrams that constrain wave propagation for certain combinations of parameters. A specific application to propagation of compressible waves in the solar chromosphere is given.
MAGNETOACOUSTIC WAVES IN A PARTIALLY IONIZED TWO-FLUID PLASMA
Soler, Roberto; Ballester, Jose Luis; Carbonell, Marc
2013-01-01
Compressible disturbances propagate in a plasma in the form of magnetoacoustic waves driven by both gas pressure and magnetic forces. In partially ionized plasmas the dynamics of ionized and neutral species are coupled due to ion-neutral collisions. As a consequence, magnetoacoustic waves propagating through a partially ionized medium are affected by ion-neutral coupling. The degree to which the behavior of the classic waves is modified depends on the physical properties of the various species and on the relative value of the wave frequency compared to the ion-neutral collision frequency. Here, we perform a comprehensive theoretical investigation of magnetoacoustic wave propagation in a partially ionized plasma using the two-fluid formalism. We consider an extensive range of values for the collision frequency, ionization ratio, and plasma β, so that the results are applicable to a wide variety of astrophysical plasmas. We determine the modification of the wave frequencies and study the frictional damping due to ion-neutral collisions. Approximate analytic expressions for the frequencies are given in the limit case of strongly coupled ions and neutrals, while numerically obtained dispersion diagrams are provided for arbitrary collision frequencies. In addition, we discuss the presence of cutoffs in the dispersion diagrams that constrain wave propagation for certain combinations of parameters. A specific application to propagation of compressible waves in the solar chromosphere is given
Non linear dynamics of magnetic islands in fusion plasmas
Meshcheriakov, D.
2012-10-01
In this thesis we investigate the issues of linear stability of the tearing modes in a presence of both curvature and diamagnetic rotation using the non linear full-MHD toroidal code XTOR-2F, which includes anisotropic heat transport, diamagnetic and geometrical effects. This analysis is applied to one of the fully non-inductive discharges on Tore-Supra. Such experiments are crucially important to demonstrate reactor scale steady state operation for the tokamak. The possibility of a full linear stabilization of the tearing modes by diamagnetic rotation in the presence of toroidal curvature is shown. The stabilization threshold does not follow the classical scaling law connecting the growth rate of islands to plasma conductivity, measured here by the Lundquist number (S). However, for numerical reasons, the conductivity used in the simulations is lower than that of the experiment, which raises the question of extrapolation of the obtained results to the experimental situation. The extrapolation of the obtained results requires simulations with several different conductivities. It predicts that the mode at q = 2 surface to be stable at value of diamagnetic frequency consistent with the experimental one at S = S(exp). In the linearly stable domain, the mode is metastable: saturation level depends on the seed island size. In the non linear regime, the saturation of n=1, m=2 mode is found to be strongly reduced by diamagnetic rotation and by Lundquist number. However, the extrapolation to the experimental situation shows that if the island is destabilized, it will saturate at a detectable level for the Tore Supra diagnostic. For a large plasma aspect ratio (i.e. weak curvature effects), the reduction of the saturated width by diamagnetic frequency takes the form of a jump reminiscent of multiple states evidenced in slab geometry case. The question of extrapolation of the obtained results towards future generation of fusion devices is also addressed. In particular, for
Energetically resolved multiple-fluid equilibria of tokamak plasmas
Hole, M J; Dennis, G
2009-01-01
In many magnetically confined fusion experiments, a significant fraction of the stored energy of the plasma resides in energetic, or non-thermal, particle populations. Despite this, most equilibrium treatments are based on MHD: a single fluid treatment which assumes a Maxwell-Boltzmann distribution function. Detailed magnetic reconstruction based on this treatment ignore the energetic complexity of the plasma and can result in model-data inconsistencies, such as thermal pressure profiles which are inconsistent with the total stored kinetic energy of the plasma. Alternatively, ad hoc corrections to the pressure profile, such as summing the energetic and thermal pressures, have poor theoretical justification. Motivated by this omission, we generalize ideal MHD one step further: we consider multiple quasi-neutral fluids, each in thermal equilibrium and each thermally insulated from each other-no population mixing occurs. Kinetically, such a model may be able to describe the ion or electron distribution function in regions of velocity phase space with a large number of particles, at the expense of more weakly populated phase space, which may have uncharacteristically high temperature and hence pressure. As magnetic equilibrium effects increase with the increase in pressure, our work constitutes an upper limit to the effect of energetic particles. When implemented into an existing solver, FLOW (Guazzotto et al 2004 Phys. Plasmas 11, 604-14), it becomes possible to qualitatively explore the impact of resolving the energetic populations on plasma equilibrium configurations in realistic geometry. Deploying the modified code, FLOW-M, on a high performance spherical torus configuration, we find that the effect of variations of the pressure, poloidal flow and toroidal flow of the energetic populations is qualitatively similar to variations in the background plasma. We also study the robustness of the equilibrium to uncertainties in the current profile and the energetic
Nonlinear plasma wave models in 3D fluid simulations of laser-plasma interaction
Chapman, Thomas; Berger, Richard; Arrighi, Bill; Langer, Steve; Banks, Jeffrey; Brunner, Stephan
2017-10-01
Simulations of laser-plasma interaction (LPI) in inertial confinement fusion (ICF) conditions require multi-mm spatial scales due to the typical laser beam size and durations of order 100 ps in order for numerical laser reflectivities to converge. To be computationally achievable, these scales necessitate a fluid-like treatment of light and plasma waves with a spatial grid size on the order of the light wave length. Plasma waves experience many nonlinear phenomena not naturally described by a fluid treatment, such as frequency shifts induced by trapping, a nonlinear (typically suppressed) Landau damping, and mode couplings leading to instabilities that can cause the plasma wave to decay rapidly. These processes affect the onset and saturation of stimulated Raman and Brillouin scattering, and are of direct interest to the modeling and prediction of deleterious LPI in ICF. It is not currently computationally feasible to simulate these Debye length-scale phenomena in 3D across experimental scales. Analytically-derived and/or numerically benchmarked models of processes occurring at scales finer than the fluid simulation grid offer a path forward. We demonstrate the impact of a range of kinetic processes on plasma reflectivity via models included in the LPI simulation code pF3D. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.
Sheared-flow induced confinement transition in a linear magnetized plasma
Zhou, S.; Heidbrink, W. W.; Boehmer, H.; McWilliams, R.; Carter, T. A.; Vincena, S.; Friedman, B.; Schaffner, D.
2012-01-01
A magnetized plasma cylinder (12 cm in diameter) is induced by an annular shape obstacle at the Large Plasma Device [W. Gekelman, H. Pfister, Z. Lucky, J. Bamber, D. Leneman, and J. Maggs, Rev. Sci. Instrum. 62, 2875 (1991)]. Sheared azimuthal flow is driven at the edge of the plasma cylinder through edge biasing. Strong fluctuations of density and potential (δn /n~eδφ/kTe~0.5) are observed at the plasma edge, accompanied by a large density gradient (Ln=|∇lnn |-1~2cm) and shearing rate (γ ~300kHz). Edge turbulence and cross-field transport are modified by changing the bias voltage (Vbias) on the obstacle and the axial magnetic field (Bz) strength. In cases with low Vbias and large Bz, improved plasma confinement is observed, along with steeper edge density gradients. The radially sheared flow induced by E ×B drift dramatically changes the cross-phase between density and potential fluctuations, which causes the wave-induced particle flux to reverse its direction across the shear layer. In cases with higher bias voltage or smaller Bz, large radial transport and rapid depletion of the central plasma density are observed. Two-dimensional cross-correlation measurement shows that a mode with azimuthal mode number m =1 and large radial correlation length dominates the outward transport in these cases. Linear analysis based on a two-fluid Braginskii model suggests that the fluctuations are driven by both density gradient (drift wave like) and flow shear (Kelvin-Helmholtz like) at the plasma edge.
Sheared-flow induced confinement transition in a linear magnetized plasma
Zhou, S.; Heidbrink, W. W.; Boehmer, H.; McWilliams, R.; Carter, T. A.; Vincena, S.; Friedman, B.; Schaffner, D.
2012-01-01
A magnetized plasma cylinder (12 cm in diameter) is induced by an annular shape obstacle at the Large Plasma Device [W. Gekelman, H. Pfister, Z. Lucky, J. Bamber, D. Leneman, and J. Maggs, Rev. Sci. Instrum. 62, 2875 (1991)]. Sheared azimuthal flow is driven at the edge of the plasma cylinder through edge biasing. Strong fluctuations of density and potential (δn/n∼eδφ/kT e ∼0.5) are observed at the plasma edge, accompanied by a large density gradient (L n =∇lnn -1 ∼2cm) and shearing rate (γ∼300kHz). Edge turbulence and cross-field transport are modified by changing the bias voltage (V bias ) on the obstacle and the axial magnetic field (B z ) strength. In cases with low V bias and large B z , improved plasma confinement is observed, along with steeper edge density gradients. The radially sheared flow induced by ExB drift dramatically changes the cross-phase between density and potential fluctuations, which causes the wave-induced particle flux to reverse its direction across the shear layer. In cases with higher bias voltage or smaller B z , large radial transport and rapid depletion of the central plasma density are observed. Two-dimensional cross-correlation measurement shows that a mode with azimuthal mode number m=1 and large radial correlation length dominates the outward transport in these cases. Linear analysis based on a two-fluid Braginskii model suggests that the fluctuations are driven by both density gradient (drift wave like) and flow shear (Kelvin-Helmholtz like) at the plasma edge.
Numerical solution of plasma fluid equations using locally refined grids
Colella, P.
1997-01-01
This paper describes a numerical method for the solution of plasma fluid equations on block-structured, locally refined grids. The plasma under consideration is typical of those used for the processing of semiconductors. The governing equations consist of a drift-diffusion model of the electrons and an isothermal model of the ions coupled by Poisson's equation. A discretization of the equations is given for a uniform spatial grid, and a time-split integration scheme is developed. The algorithm is then extended to accommodate locally refined grids. This extension involves the advancement of the discrete system on a hierarchy of levels, each of which represents a degree of refinement, together with synchronization steps to ensure consistency across levels. A brief discussion of a software implementation is followed by a presentation of numerical results
Vitamin B6 in plasma and cerebrospinal fluid of children.
Monique Albersen
Full Text Available Over the past years, the essential role of vitamin B6 in brain development and functioning has been recognized and genetic metabolic disorders resulting in functional vitamin B6 deficiency have been identified. However, data on B6 vitamers in children are scarce.B6 vitamer concentrations in simultaneously sampled plasma and cerebrospinal fluid (CSF of 70 children with intellectual disability were determined by ultra performance liquid chromatography-tandem mass spectrometry. For ethical reasons, CSF samples could not be obtained from healthy children. The influence of sex, age, epilepsy and treatment with anti-epileptic drugs, were investigated.The B6 vitamer composition of plasma (pyridoxal phosphate (PLP > pyridoxic acid > pyridoxal (PL differed from that of CSF (PL > PLP > pyridoxic acid > pyridoxamine. Strong correlations were found for B6 vitamers in and between plasma and CSF. Treatment with anti-epileptic drugs resulted in decreased concentrations of PL and PLP in CSF.We provide concentrations of all B6 vitamers in plasma and CSF of children with intellectual disability (±epilepsy, which can be used in the investigation of known and novel disorders associated with vitamin B6 metabolism as well as in monitoring of the biochemical effects of treatment with vitamin B6.
Plasma simulation of electron avalanche in a linear thyratron
Kushner, M.J.
1985-01-01
Thyratrons typically operate at sufficiently small PD (pressure x electrode separation) that holdoff is obtained by operating on the near side of the Paschen curve, and by shielding the slot in the control grid so there is no straight line path for electrons to reach the anode from the cathode. Electron avalanche is initiated by pulsing the control grid to a high voltage. Upon collapse of voltage in the cathode-control grid space, the discharge is sustained by penetration of potential through the control grid slot into the cathode-control grid region. To better understand the electron avalanche process in multi-grid and slotted structures such as thyratrons, a plasma simulation code has been constructed. This effort is in support of a companion program in which a linear thyratron is being electrically and spectroscopically characterized
A new linear plasma device for various edge plasma studies at SWIP
Xu, Min; Zheng, Pengfei; Tynan, George; Che, Tong; Wang, Zhanhui; Guo, Dong; Wei, Ran
2017-10-01
To facilitate the plasma-material interactions (PMI) studies, Southwestern Institute of Physics (SWIP) has constructed a linear plasma device. It is comprised of a source chamber (Φ 0.4 m), a target chamber (Φ 0.9 m), 15 magnets with different sizes, and power supplies with the total power of a few hundred kilowatts, etc. A maximum magnetic field of 0.3 Tesla along the axial direction can be produced. The current of each of the 15 magnets can be independently controlled. More than 60 ports are available for diagnostics, with the sizes vary from Φ 50 mm to Φ 150 mm. Rectangular ports of 190 mm × 270 mm are also available. 12 ports looking at the sample holder are specially designed for ion beam injection, of which the axes are 25 to the chamber axis. The device is equipped with a LaB6 hot cathode plasma source, which is able to generate steady-state H/D/He plasmas with a diameter of Φ 100 mm, density of 1x1019 /m3 , and a particle flux of 1022 1023 n/m2 .s. The electron temperature is usually a few eV. Further, a Helicon RF plasma source is also planned for plasma transport studies. Int'l Sci & Tech Cooperation Program of China (No. 2015DFA61760).
Optimized parallel convolutions for non-linear fluid models of tokamak ηi turbulence
Milovich, J.L.; Tomaschke, G.; Kerbel, G.D.
1993-01-01
Non-linear computational fluid models of plasma turbulence based on spectral methods typically spend a large fraction of the total computing time evaluating convolutions. Usually these convolutions arise from an explicit or semi implicit treatment of the convective non-linearities in the problem. Often the principal convective velocity is perpendicular to magnetic field lines allowing a reduction of the convolution to two dimensions in an appropriate geometry, but beyond this, different models vary widely in the particulars of which mode amplitudes are selectively evolved to get the most efficient representation of the turbulence. As the number of modes in the problem, N, increases, the amount of computation required for this part of the evolution algorithm then scales as N 2 /timestep for a direct or analytic method and N ln N/timestep for a pseudospectral method. The constants of proportionality depend on the particulars of mode selection and determine the size problem for which the method will perform equally. For large enough N, the pseudospectral method performance is always superior, though some problems do not require correspondingly high resolution. Further, the Courant condition for numerical stability requires that the timestep size must decrease proportionately as N increases, thus accentuating the need to have fast methods for larger N problems. The authors have developed a package for the Cray system which performs these convolutions for a rather arbitrary mode selection scheme using either method. The package is highly optimized using a combination of macro and microtasking techniques, as well as vectorization and in some cases assembly coded routines. Parts of the package have also been developed and optimized for the CM200 and CM5 system. Performance comparisons with respect to problem size, parallelization, selection schemes and architecture are presented
Multi-CPU plasma fluid turbulence calculations on a CRAY Y-MP C90
Lynch, V.E.; Carreras, B.A.; Leboeuf, J.N.; Curtis, B.C.; Troutman, R.L.
1993-01-01
Significant improvements in real-time efficiency have been obtained for plasma fluid turbulence calculations by microtasking the nonlinear fluid code KITE in which they are implemented on the CRAY Y-MP C90 at the National Energy Research Supercomputer Center (NERSC). The number of processors accessed concurrently scales linearly with problem size. Close to six concurrent processors have so far been obtained with a three-dimensional nonlinear production calculation at the currently allowed memory size of 80 Mword. With a calculation size corresponding to the maximum allowed memory of 200 Mword in the next system configuration, they expect to be able to access close to ten processors of the C90 concurrently with a commensurate improvement in real-time efficiency. These improvements in performance are comparable to those expected from a massively parallel implementation of the same calculations on the Intel Paragon
Multi-CPU plasma fluid turbulence calculations on a CRAY Y-MP C90
Lynch, V.E.; Carreras, B.A.; Leboeuf, J.N.; Curtis, B.C.; Troutman, R.L.
1993-01-01
Significant improvements in real-time efficiency have been obtained for plasma fluid turbulence calculations by microtasking the nonlinear fluid code KITE in which they are implemented on the CRAY Y-MP C90 at the National Energy Research Supercomputer Center (NERSC). The number of processors accessed concurrently scales linearly with problem size. Close to six concurrent processors have so far been obtained with a three-dimensional nonlinear production calculation at the currently allowed memory size of 80 Mword. With a calculation size corresponding to the maximum allowed memory of 200 Mword in the next system configuration, we expect to be able to access close to nine processors of the C90 concurrently with a commensurate improvement in real-time efficiency. These improvements in performance are comparable to those expected from a massively parallel implementation of the same calculations on the Intel Paragon
Lemoine, Lieselotte; Thijssen, Elsy; Noben, Jean-Paul; Adriaensens, Peter; Carleer, Robert; Speeten, Kurt Van der
2018-04-15
Oxaliplatin is a platinum (Pt) 1 containing antineoplastic agent that is applied in current clinical practice for the treatment of colon and appendiceal neoplasms. A fully validated, highly sensitive, high throughput inductively coupled plasma mass spectrometry (ICP-MS) method is provided to quantify the total Pt content in plasma, plasma ultrafiltrate, urine and peritoneal fluid. In this ICP-MS approach, the only step of sample preparation is a 1000-fold dilution in 0.5% nitric acid, allowing the analysis of 17 samples per hour. Detection of Pt was achieved over a linear range of 0.01-100 ng/mL. The limit of quantification was 18.0 ng/mL Pt in plasma, 8.0 ng/mL in ultrafiltrate and 6.1 ng/mL in urine and peritoneal fluid. The ICP-MS method was further validated for inter-and intraday precision and accuracy (≤15%), recovery, robustness and stability. Short-term storage of the biofluids, for 14 days, can be performed at -4 °C, -24 °C and -80 °C. As to long-term stability, up to 5 months, storage at -80 °C is encouraged. Furthermore, a timeline assessing the total and unbound Pt fraction in plasma and ultrafiltrate over a period of 45 h is provided. Following an incubation period of 5 h at 37 °C, 19-21% of Pt was recovered in the ultrafiltrate, emphasizing the extensive and rapid binding of oxaliplatin-derived Pt to plasma proteins. The described method can easily be implemented in a routine setting for pharmacokinetic studies in patients treated with oxaliplatin-based hyperthermic intraperitoneal perioperative chemotherapy. Copyright © 2018 Elsevier B.V. All rights reserved.
Plasma and cerebrospinal fluid pharmacokinetics of flurbiprofen in children
Kumpulainen, Elina; Välitalo, Pyry; Kokki, Merja; Lehtonen, Marko; Hooker, Andrew; Ranta, Veli-Pekka; Kokki, Hannu
2010-01-01
AIMS This study was designed to characterize paediatric pharmacokinetics and central nervous system exposure of flurbiprofen. METHODS The pharmacokinetics of flurbiprofen were studied in 64 healthy children aged 3 months to 13 years, undergoing surgery with spinal anaesthesia. Children were administered preoperatively a single dose of flurbiprofen intravenously as prodrug (n = 27) or by mouth as syrup (n = 37). A single cerebrospinal fluid (CSF) sample (n = 60) was collected at the induction of anaesthesia, and plasma samples (n = 304) before, during and after the operation (up to 20 h after administration). A population pharmacokinetic model was built using the NONMEM software package. RESULTS Flurbiprofen concentrations in plasma were well described by a three compartment model. The apparent bioavailability of oral flurbiprofen syrup was 81%. The estimated clearance (CL) was 0.96 l h−1 70 kg−1. Age did not affect the clearance after weight had been included as a covariate. The estimated volume of distribution at steady state (Vss) was 8.1 l 70 kg−1. Flurbiprofen permeated into the CSF, reaching concentrations that were seven-fold higher compared with unbound plasma concentrations. CONCLUSIONS Flurbiprofen pharmacokinetics can be described using only weight as a covariate in children above 6 months, while more research is needed in neonates and in younger infants. PMID:20840447
A new linear plasma device for the study of plasma waves in the electron magnetohydrodynamics regime
Joshi, Garima; Ravi, G.; Mukherjee, S.
2018-06-01
A new, user-friendly, linear plasma device has been developed in our laboratory where a quiescent (Δ n/n ≈ 1%), low temperature (1-10 eV), pulsed (3-10 ms) plasma can be produced over a large uniform region of 30-40 cm diameter and 40 cm length. Salient features of the device include the flexibility of tuning the plasma density in the range of 10^{10} to 10^{12} cm^{-3} and capability of scanning the plasma and field parameters in two dimensions with a precision of electromagnetic field parameters by miniature magnetic probes and Rogowski coils. The plasma produced is uniform and essentially unbounded for performing experiments on waves and turbulence. The whole device can be operated single-handedly by undergraduate or graduate students. The device can be opened, serviced, new antennas/probes installed and ready for operation in a matter of hours. Some results on the excitation of electromagnetic structures in the context of electron magnetohydrodynamics (EMHD) are also presented to demonstrate the suitability of the device for carrying out such experiments.
Two-dimensional single fluid MHD simulations of plasma opening switches
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
Characterization of the porcine synovial fluid proteome and a comparison to the plasma proteome
Tue Bjerg Bennike
2015-12-01
In addition, we analyzed the proteome of human plasma, and compared the proteomes to the obtained porcine synovial fluid proteome. The proteome of the two body fluids were found highly similar, underlining the detected plasma derived nature of many synovial fluid components. The healthy porcine synovial fluid proteomics data, human rheumatoid arthritis synovial fluid proteomics data used in the method optimization, human plasma proteomics data, and search results, have been deposited to the ProteomeXchange Consortium via the PRIDE partner repository with the dataset identifier PXD000935.
Low frequency fluid drift turbulence in magnetised plasmas
Scott, B.
2001-03-01
We start with the first principles of fluid dynamics and classical electrodynamics and then find the regime in which we can reduce to quasineutral dynamics, which also implicitly underlies MHD. Then, we find the limits under which we can specialise to the MHD model as a subset, first of two fluid dynamics, then of the fluid drift dynamics that results when the motions are not vigorous enough to compress the magnetic field. In Chapters 4 and 5 we find the basic character of small disturbances in this system. Chapters 6 through 9 treat various aspects of fluid drift turbulence, also called drift wave turbulence, moving from a simple consideration of the underlying nonlinear dynamics, to some methods by which one can diagnose computations to find out what is going on, and then to the nonlinear instability which is the hallmark of this physics, and then to the interactions with large scale sheared flows. Chapter 10 introduces interchange turbulence, which is the plasma analog of the buoyant convection well known from fluid dynamics. Chapters 11 through 13 treat electromagnetic drift wave turbulence in closed magnetic field geometry, starting with a simplified model treating only the electron pressure and then introducing the electron and ion temperatures. Chapter 14 treats the basic characteristics of the transport that results from fluid drift turbulence, as this is quite different from the kinetic diffusion, such as heat conduction, that is more familiar. Appendices A and B treat the details of the numerical methods and models of magnetic field geometry necessary to treat all but the simplest cases. For this subject is dominated by nonlinear physics and therefore numerical computation. Computations therefore form an integral part of its study right from the beginning. Citations to the literature are not intended to be comprehensive but to serve as starting points for further reading, a section for which is included in every chapter. Much of this work is very new, and
Linear and nonlinear ion-acoustic waves in nonrelativistic quantum plasmas with arbitrary degeneracy
Haas, Fernando; Mahmood, Shahzad
2015-11-01
Linear and nonlinear ion-acoustic waves are studied in a fluid model for nonrelativistic, unmagnetized quantum plasma with electrons with an arbitrary degeneracy degree. The equation of state for electrons follows from a local Fermi-Dirac distribution function and applies equally well both to fully degenerate and classical, nondegenerate limits. Ions are assumed to be cold. Quantum diffraction effects through the Bohm potential are also taken into account. A general coupling parameter valid for dilute and dense plasmas is proposed. The linear dispersion relation of the ion-acoustic waves is obtained and the ion-acoustic speed is discussed for the limiting cases of extremely dense or dilute systems. In the long-wavelength limit, the results agree with quantum kinetic theory. Using the reductive perturbation method, the appropriate Korteweg-de Vries equation for weakly nonlinear solutions is obtained and the corresponding soliton propagation is analyzed. It is found that soliton hump and dip structures are formed depending on the value of the quantum parameter for the degenerate electrons, which affect the phase velocities in the dispersive medium.
Local invariants in non-ideal flows of neutral fluids and two-fluid plasmas
Zhu, Jian-Zhou
2018-03-01
The main objective is the locally invariant geometric object of any (magneto-)fluid dynamics with forcing and damping (nonideal), while more attention is paid to the untouched dynamical properties of two-fluid fashion. Specifically, local structures, beyond the well-known "frozen-in" to the barotropic flows of the generalized vorticities, of the two-fluid model of plasma flows are presented. More general non-barotropic situations are also considered. A modified Euler equation [T. Tao, "Finite time blowup for Lagrangian modifications of the three-dimensional Euler equation," Ann. PDE 2, 9 (2016)] is also accordingly analyzed and remarked from the angle of view of the two-fluid model, with emphasis on the local structures. The local constraints of high-order differential forms such as helicity, among others, find simple formulation for possible practices in modeling the dynamics. Thus, the Cauchy invariants equation [N. Besse and U. Frisch, "Geometric formulation of the Cauchy invariants for incompressible Euler flow in flat and curved spaces," J. Fluid Mech. 825, 412 (2017)] may be enabled to find applications in non-ideal flows. Some formal examples are offered to demonstrate the calculations, and particularly interestingly the two-dimensional-three-component (2D3C) or the 2D passive scalar problem presents that a locally invariant Θ = 2θζ, with θ and ζ being, respectively, the scalar value of the "vertical velocity" (or the passive scalar) and the "vertical vorticity," may be used as if it were the spatial density of the globally invariant helicity, providing a Lagrangian prescription to control the latter in some situations of studying its physical effects in rapidly rotating flows (ubiquitous in atmosphere of astrophysical objects) with marked 2D3C vortical modes or in purely 2D passive scalars.
Knotted solutions for linear and nonlinear theories: Electromagnetism and fluid dynamics
Daniel W.F. Alves
2017-10-01
Full Text Available We examine knotted solutions, the most simple of which is the “Hopfion”, from the point of view of relations between electromagnetism and ideal fluid dynamics. A map between fluid dynamics and electromagnetism works for initial conditions or for linear perturbations, allowing us to find new knotted fluid solutions. Knotted solutions are also found to be solutions of nonlinear generalizations of electromagnetism, and of quantum-corrected actions for electromagnetism coupled to other modes. For null configurations, electromagnetism can be described as a null pressureless fluid, for which we can find solutions from the knotted solutions of electromagnetism. We also map them to solutions of Euler's equations, obtained from a type of nonrelativistic reduction of the relativistic fluid equations.
Anti-Müllerian Hormone in Peritoneal Fluid and Plasma From Women With and Without Endometriosis.
Hipp, Heather; Loucks, Tammy L; Nezhat, Ceana; Sidell, Neil; Session, Donna R
2015-09-01
Anti-Müllerian hormone (AMH) has potential local effects on ovarian function and endometrial tissue, including endometriosis, but its presence in peritoneal fluid is not fully understood. This is a cross-sectional study evaluating AMH in peritoneal fluid and plasma from women with endometriosis (N = 61) and from control women without endometriosis (N = 36). There was a significant correlation between AMH in plasma and peritoneal fluid from both patients with endometriosis (r(2) = .767 [P peritoneal fluid in women with and without endometriosis. There were no differences in the plasma or peritoneal fluid AMH in women with endometriosis versus control women. The strong relationship between plasma and peritoneal fluid may allow plasma AMH to be a marker for peritoneal AMH in studies evaluating the local effects of AMH. © The Author(s) 2015.
Revisiting linear plasma waves for finite value of the plasma parameter
Grismayer, Thomas; Fahlen, Jay; Decyk, Viktor; Mori, Warren
2010-11-01
We investigate through theory and PIC simulations the Landau-damping of plasma waves with finite plasma parameter. We concentrate on the linear regime, γφB, where the waves are typically small and below the thermal noise. We simulate these condition using 1,2,3D electrostatic PIC codes (BEPS), noting that modern computers now allow us to simulate cases where (nλD^3 = [1e2;1e6]). We study these waves by using a subtraction technique in which two simulations are carried out. In the first, a small wave is initialized or driven, in the second no wave is excited. The results are subtracted to provide a clean signal that can be studied. As nλD^3 is decreased, the number of resonant electrons can be small for linear waves. We show how the damping changes as a result of having few resonant particles. We also find that for small nλD^3 fluctuations can cause the electrons to undergo collisions that eventually destroy the initial wave. A quantity of interest is the the life time of a particular mode which depends on the plasma parameter and the wave number. The life time is estimated and then compared with the numerical results. A surprising result is that even for large values of nλD^3 some non-Vlasov discreteness effects appear to be important.
Automated finder for the critical condition on the linear stability of fluid motions
Fujimura, Kaoru
1990-03-01
An automated finder routine for the critical condition on the linear stability of fluid motions is proposed. The Newton-Raphson method was utilized for an iteration to solve nonlinear eigenvalue problems appeared in the analysis. The routine was applied to linear stability problem of a free convection between vertical parallel plates with different non-uniform temperatures as well as a plane Poiseuille flow. An efficiency of the finder routine is demonstrated for several parameter sets, numerically. (author)
On coupling fluid plasma and kinetic neutral physics models
I. Joseph
2017-08-01
Full Text Available The coupled fluid plasma and kinetic neutral physics equations are analyzed through theory and simulation of benchmark cases. It is shown that coupling methods that do not treat the coupling rates implicitly are restricted to short time steps for stability. Fast charge exchange, ionization and recombination coupling rates exist, even after constraining the solution by requiring that the neutrals are at equilibrium. For explicit coupling, the present implementation of Monte Carlo correlated sampling techniques does not allow for complete convergence in slab geometry. For the benchmark case, residuals decay with particle number and increase with grid size, indicating that they scale in a manner that is similar to the theoretical prediction for nonlinear bias error. Progress is reported on implementation of a fully implicit Jacobian-free Newton–Krylov coupling scheme. The present block Jacobi preconditioning method is still sensitive to time step and methods that better precondition the coupled system are under investigation.
Finite element procedures for coupled linear analysis of heat transfer, fluid and solid mechanics
Sutjahjo, Edhi; Chamis, Christos C.
1993-01-01
Coupled finite element formulations for fluid mechanics, heat transfer, and solid mechanics are derived from the conservation laws for energy, mass, and momentum. To model the physics of interactions among the participating disciplines, the linearized equations are coupled by combining domain and boundary coupling procedures. Iterative numerical solution strategy is presented to solve the equations, with the partitioning of temporal discretization implemented.
Non-linear free streaming in Vlasov plasma
Sedláček, Zdeněk
2004-01-01
Roč. 54, suppl.C (2004), C82-C88 ISSN 0011-4626. [Symposium on Plasma Physics and Technology/21th./. Prague, 14.06.2004-17.06.2004] Institutional research plan: CEZ:AV0Z2043910 Keywords : plasma oscillations * Vlasov equation Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 0.292, year: 2004
Relaxation and self-organization in two-dimensional plasma and neutral fluid flow systems
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
Conn, R.W.; Mau, T.K.; Prinja, A.K.
1983-01-01
A physical model for the space and time evolution of the primary parameters of ordinary and burning tokamak plasmas is described by employing a fluid plasma treatment coupled to a magnetohydrodynamic equilibrium description, the solution to the appropriate Maxwell equations, and the solution of the linear transport equation describing neutral atom transport in plasmas. The specific problems of plasma heating by ion cyclotron radiofrequency (ICRF) waves and neutral atom transport in the plasma edge and in complicated geometrical components such as divertor channels or pumped limiter structures are analyzed. A theoretical, onedimensional slab model of ICRF heating at ω = 2ω/SUB cD/ is developed and applied to determine the space-time response of tokamak plasmas. Generally, strong single-pass absorption is found for high-density, high (β) plasmas using a low k 11 spectrum (0.05 to 0.1 cm -1 ) although for (β > 1%, electron Landau damping becomes important. Deterministic and Monte Carlo methods to solve the neutral atom transport problem are described. Specific application to determine the spectrum of neutral atoms emerging from the duct of a pump limiter shows it to be hard (mean energy > 20 eV), indicating very incomplete energy thermalization. Uncertainties are identified in the overall problem of dynamic burning plasma analysis caused by the complexity of the problem itself and by uncertainties in fundamental areas such as plasma transport coefficients, stability, and plasma edge physics
Lee, S. H.; Shulika, Olga.; Kim, K. N.; Yeom, G. Y.; Lee, J. K.
2004-09-01
As the technology of plasma processing progresses, there is a continuing demand for higher plasma density, uniformity over large areas and greater control over plasma parameters to optimize the processes of etching, deposition and surface treatment. Traditionally, the external planar ICP sources with low pressure high density plasma have limited scale-up capabilities due to its high impedance accompanied by the large antenna size. Also due to the cost and thickness of their dielectric material in order to generate uniform plasma. In this study the novel internal-type linear inductive antenna system (1,020mm¡¿830mm¡¿437mm) with permanent magnet arrays are investigated to improve both the plasma density and the uniformity of LAPS (Large Area Plasma Source) for FPD processing. Generally plasma discharges are enhanced because the inductance of the novel antenna (termed as the double comb antenna) is lower than that of the serpentine-type antenna and also the magnetic confinement of electron increases the power absorption efficiency. The uniformity is improved by reducing the standing wave effect. The total length of antenna is comparable to the driving rf wavelength to cause the plasma nonuniformity. To describe the discharge phenomenon we have developed a magnetized two-dimensional fluid simulation. This work was supported by National Research Laboratory (NRL) Program of the Korea Ministry of Science and Technology. [References] 1. J.K.Lee, Lin Meng, Y.K.Shin, H,J,Lee and T.H.Chung, ¡°Modeling and Simulation of a Large-Area Plasma Source¡±, Jpn. J. Appl. Phys. Vol.36(1997) pp. 5714-5723 2. S.E.Park, B.U.Cho, Y.J.Lee*, and G.Y.Yeom*, and J.K.Lee, ¡°The Characteristics of Large Area Processing Plasmas¡±, IEEE Trans. Plasma Sci., Vol.31 ,No.4(2003) pp. 628-637
Belyakov, V.; Kavin, A.; Rumyantsev, E.; Kharitonov, V.; Misenov, B.; Ovsyannikov, A.; Ovsyannikov, D.; Veremei, E.; Zhabko, A.; Mitrishkin, Y.
1999-01-01
This paper is focused on the linear quadratic Gaussian (LQG) controller synthesis methodology for the ITER plasma current, position and shape control system as well as power derivative management system. It has been shown that some poloidal field (PF) coils have less influence on reference plasma-wall gaps control during plasma disturbances and hence they have been used to reduce total control power derivative by means of the additional non-linear feedback. The design has been done on the basis of linear models. Simulation was provided for non-linear model and results are presented and discussed. (orig.)
Plasma-treated carbonyl iron particles as a dispersed phase in magnetorheological fluids
Sedlačík, M.; Pavlínek, V.; Lehocký, M.; Mráček, A.; Grulich, O.; Švrčinová, P. (Petra); Filip, P. (Petr); Vesel, A.
2011-01-01
The aim of this paper is to document suitability of plasma-treated carbonyl iron particles as a dispersed phase in magnetorheological fluids. Surface-modified carbonyl iron particles were prepared via their exposure to 50% argon and 50% octafluorocyclobutane plasma. The X-ray photoelectron spectroscopy was used for analysis of chemical bonding states in the surface layer. Plasma-treated particles were adopted for a dispersed phase in magnetorheological (MR) fluids, and the MR behaviour was in...
Plasma heating by radio frequency in the LISA linear machine
Cunha Raposo, C. da.
1985-05-01
The characteristics of an experimental apparatus to produce helium plasma by radio frequency and to study its behavior when confined by a magnetic field with mirrors is shown. The plasma was produced by a microwave source of 2.45 GHz and 800 Watts, operating in steady and pulsed state. The plasma parameters were studied as a function of an external magnetic field, for large and small resonance regions. The axial and radial magnetic fields were mapped for each region in order to verify the spatial distribution, particle orbits, and energy confinement time according to the energy balance equation. As a consequence of the influence of the radio frequency (RF) voltage in the plasma the Bohm theory of plasma prob was modified. The diagnostic was done with plane movable electrostatic probe, Hall probe, magnetic probe, diamagnetic coil and spectrography. (Author) [pt
Study of the linear and non-linear coupling of the LH wave to the tokamak plasmas
Preynas, M.
2012-10-01
In order to achieve long pulse operation with a tokamak, additional heating and current drive systems are necessary. High frequency antennas, which deliver several megawatts of power to the plasma, are currently used in several tokamaks. Moreover, a good control of the coupling of the wave launched by the antenna to the edge plasma is required to optimize the efficiency of heating and current drive LH systems. However, non-linear effects which depend on the level of injected power in the plasma strongly damage the coupling of the LH wave at particular edge parameters (density and temperature profiles). Results presented in the manuscript deal with the study of the linear and non-linear coupling of the LH wave to the plasma. In the framework of the commissioning of the Passive Active Multijunction antenna in 2009 on the Tore Supra tokamak aiming at validating the LH system suggested for ITER, the characterisation of its coupling properties was realized from low power experiments. The experimental results, which are compared with the linear coupling code ALOHA, have validated the theoretical predictions of good coupling at edge plasma density around the cut-off density. Besides, the ponderomotive effect is clearly identified as responsible for the deterioration in the coupling of the wave, which is measured under particular edge plasma conditions. A theoretical model combining the coupling of the LH wave with the ponderomotive force is suggested to explain the experimental observations. Thus, a new full wave code (named PICCOLO-2D) was developed and results from simulations validate the working hypothesis of the contribution of the ponderomotive effect in the non-linear observations of LHCD coupling on Tore Supra. (author)
A hybrid gyrokinetic ion and isothermal electron fluid code for astrophysical plasma
Kawazura, Y.; Barnes, M.
2018-05-01
This paper describes a new code for simulating astrophysical plasmas that solves a hybrid model composed of gyrokinetic ions (GKI) and an isothermal electron fluid (ITEF) Schekochihin et al. (2009) [9]. This model captures ion kinetic effects that are important near the ion gyro-radius scale while electron kinetic effects are ordered out by an electron-ion mass ratio expansion. The code is developed by incorporating the ITEF approximation into AstroGK, an Eulerian δf gyrokinetics code specialized to a slab geometry Numata et al. (2010) [41]. The new code treats the linear terms in the ITEF equations implicitly while the nonlinear terms are treated explicitly. We show linear and nonlinear benchmark tests to prove the validity and applicability of the simulation code. Since the fast electron timescale is eliminated by the mass ratio expansion, the Courant-Friedrichs-Lewy condition is much less restrictive than in full gyrokinetic codes; the present hybrid code runs ∼ 2√{mi /me } ∼ 100 times faster than AstroGK with a single ion species and kinetic electrons where mi /me is the ion-electron mass ratio. The improvement of the computational time makes it feasible to execute ion scale gyrokinetic simulations with a high velocity space resolution and to run multiple simulations to determine the dependence of turbulent dynamics on parameters such as electron-ion temperature ratio and plasma beta.
B. Koren (Barry); M.R. Lewis; E.H. van Brummelen (Harald); B. van Leer
2001-01-01
textabstractA finite-volume method is presented for the computation of compressible flows of two immiscible fluids at very different densities. The novel ingredient in the method is a two-fluid linearized Godunov scheme, allowing for flux computations in case of different fluids (e.g., water and
Linear study of Kelvin-Helmholtz instability for a viscous compressible fluid
Hallo, L.; Gauthier, S.
1992-01-01
The linear phase of the process leading to a developed turbulence is particularly important for the study of flow stability. A Galerkin spectral method adapted to the study of the mixture layer of one fluid is proposed from a sheared initial velocity profile. An algebraic mapping is developed to improve accuracy near high gradient zone. Validation is obtained by analytic methods for non-viscous flow and multi-domain spectral methods for viscous and compressible flow. Rates of growth are presented for subsonic and slightly supersonic flow. An extension of the method is presented for the study of the linear stability of a mixture with variable concentration and transport properties
Source formulation for electron-impact ionization for fluid plasma simulations
Müller, S.H.; Holland, C.; Tynan, G.R.
2009-01-01
The derivation of the correct functional form of source terms in plasma fluid theory is revisited. The relation between the fluid source terms and atomic physics differential cross sections is established for particle-impact ionization. It is shown that the interface between atomic and plasma phy...... electron temperature regimes in a wide variety of basic plasma physics experiments, including the trends across different gases.......The derivation of the correct functional form of source terms in plasma fluid theory is revisited. The relation between the fluid source terms and atomic physics differential cross sections is established for particle-impact ionization. It is shown that the interface between atomic and plasma...... physics is completely described by three scalar functions of the incident particle energy. These are the total cross section and the newly introduced forward momentum and energy functions, which are properties of the differential cross sections only. For electron-impact ionization, the binary...
Linear waves in a resistive plasma with Hall current
Almaguer, J.A.
1992-01-01
Dispersion relations for the case of a magnetized plasma are determined taking into account the Hall current and a constant resistivity, η, in Ohm's law. It is found that the Hall effect is relevant only for parallel (to the equilibrium magnetic field) wave numbers in the case of uniform plasmas, giving place to a dispersive behavior. In particular, the cases of η→0 and small (nonzero) resistivity are discussed
Fluid simulations of ∇Te-driven turbulence and transport in boundary plasmas
Xu, X.Q.
1992-01-01
It is clear that the edge plasma plays a crucial role in global tokamak confinement. This paper is a report on simulations of a new drift wave type instability driven by the electron temperature gradient in tokamak scrapeoff-layers (SOL). A 2d fluid code has been developed in order to explore the anomalous transport in the boundary plasmas. The simulation consists of a set of fluid equations for the vorticity ∇ perpendicular 2 φ, the electron density n c and the temperature T c in a shearless plasma slab confined by a uniform, straight magnetic field B z with two divertor (or limiter) plates intercepting the magnetic field. The model has two regions separated by a magnetic separatrix: in the edge region inside the separatrix, the model is periodic along the magnetic field while in the SOL region outside the separatrix, the magnetic field is taken to be of finite length with model boundary conditions at diverter plates. The simulation results show that the observed linear instability agrees well with theory, and that a saturated state of turbulence is reached. In saturated turbulence, clear evidence of the expected long-wavelength mode penetration into the edge is seen, an inverse cascade of wave energy is observed. The simulation results also show that amplitudes of potential and the electron temperature fluctuations are somewhat above and the heat flux are somewhat below those of the simplest mixing-length estimates, and furthermore the large-scale radial structures of fluctuation quantities indicate that the cross-field transport is not diffusive. After saturation, the electron density and temperature profiles are flattened. A self-consistent simulation to determine the microturbulent SOL electron temperature profile has been done, the results of which reasonably agree with the experimental measurements
Asymptotic form of the classical one-component plasma fluid equation of state
DeWitt, H.E.
1976-01-01
The Monte Carlo data of Hansen for the internal energy of the classical one-component plasma in the fluid state is found to satisfy accurately a simple functional form, U/NkT = aGAMMA + bGAMMA/sup 1;4/ + c, for GAMMA > 1. The fluid static energy is very close to the bcc lattice energy of the solid, and the fluid thermal energy varies as T/sup 3;4/. Simple and accurate expressions for other thermodynamic functions for the plasma fluid are given
Characteristics of Plasma Probes in an MHD Working Fluid
Whitman, A. M.; Hsuan, Yeh [Towne School of Civil and Mechanical Engineering, University of Pennsylvania (United States)
1966-10-15
In this paper an attempt is made to formulate a theory of electrostatic probes in a high-pressure plasma in which an external electrical field may be imposed. Such a situation exists in high-pressure arc discharges and in MHD channels. First, it is shown that an adequate theory must include the ionization and recombination phenomena which were ignored in almost all previous theories. Secondly, due to the preferred direction induced by the presence of the electric field, the probe problem is no longer a symmetrical one. The analysis is based on the assumption that the three-body recombination and ionization is the dominant process. In a typical MHD working fluid, say an argon gas seeded with caesium at 2000 Degree-Sign K and one atmosphere of pressure, the penetration length I of ions and electrons, i.e. the distance that an ion or electron diffuses before recombination, is of the order of 10{sup -3} cm. (It is to be noted that ambipolar diffusion prevents the electrons from travelling much faster than the ions. ) We thus have a situation where Script-Small-L /L << 1, d/ Script-Small-L << 1, {lambda}/L <<1, and {lambda}/d >> 1, where L is the characteristic dimension of the probe {lambda} is the mean free path and d the Debye length. Because of the last condition, i. e, d << {lambda}, the space charge region is contained wholly in a ''free-falling'' zone in the immediate neighbourhood of the probe. Since, also, (d/ Script-Small-L ) << 1, the region outside of the ''free-falling'' zone is in a state of ''quasi-neutrality'', i.e. the number densities of electrons and ions are approximately equal. In this latter region, the mechanisms of diffusion and recombination are both important. The two regions must of course be matched at their connecting boundaries. Furthermore, the external boundary of the ''quasi-neutrality'' region must be matched to the discharge field. Using the approximations of the classical boundary layer theory, analytic solutions are obtained in
Non-Linear Langmuir Wave Modulation in Collisionless Plasmas
Dysthe, K. B.; Pécseli, Hans
1977-01-01
in the expressions concerning the modulation instability of a plane Langmuir wave. When the Vlasov equation for the ions is applied, a Langmuir wave is modulationally unstable for arbitrary perturbations independent of the unperturbed wave amplitude, in contrast to what is found for fluid ions. A simple analogy...
A General Nonlinear Fluid Model for Reacting Plasma-Neutral Mixtures
Meier, E T; Shumlak, U
2012-04-06
A generalized, computationally tractable fluid model for capturing the effects of neutral particles in plasmas is derived. The model derivation begins with Boltzmann equations for singly charged ions, electrons, and a single neutral species. Electron-impact ionization, radiative recombination, and resonant charge exchange reactions are included. Moments of the reaction collision terms are detailed. Moments of the Boltzmann equations for electron, ion, and neutral species are combined to yield a two-component plasma-neutral fluid model. Separate density, momentum, and energy equations, each including reaction transfer terms, are produced for the plasma and neutral equations. The required closures for the plasma-neutral model are discussed.
Longitudinal and radial MHD linear induction accelerator with hot conducting plasma core
Denno, K.
1985-01-01
Conceptual design of linear induction accelerator is presented using for the core continuum a highly conductive plasma with sustained pumping velocity. Karlovitz criterion of boundary theory is employed in the process of design
Diamond films deposited by oxygen-enhanced linear plasma chemistry
Kromka, Alexander; Babchenko, Oleg; Ižák, Tibor; Varga, Marián; Davydova, Marina; Krátká, Marie; Rezek, Bohuslav
2013-01-01
Roč. 5, č. 6 (2013), s. 509-514 ISSN 2164-6627 R&D Projects: GA ČR(CZ) GBP108/12/G108; GA ČR GAP108/12/0996 Institutional support: RVO:68378271 Keywords : diamond films * process gas chemistry * pulsed microwave plasma * surface conductivity of diamond Subject RIV: BM - Solid Matter Physics ; Magnetism
Dynamics of albumin in plasma and ascitic fluid in patients with cirrhosis
Henriksen, Jens Henrik; Siemssen, O; Krintel, J J
2001-01-01
BACKGROUND/AIMS: To determine dynamics of albumin in plasma and ascitic fluid of patients with cirrhosis. METHODS: Forty-seven patients were classified in four groups: I--patients without fluid retention; II--patients with ascites not resistant to subsequent diuretic treatment; III......--recompensated patients during diuretic treatment; and IV--patients with diuretic-resistant ascites. Transvascular and transperitoneal albumin transports were quantified by 131I-/125I-labelled human albumin. RESULTS: TER(P) (i.e. the fraction of intravascular albumin (IVM) passing from plasma into the interstitial space...... per hour) was increased in all groups. In group IV patients the transport rate of albumin from plasma into the ascitic fluid (TER(PA)) was significantly higher than the transport rate from the ascitic fluid back into the plasma: TER(AP) (0.45 vs. 0.26% IVM/h, P
Misguich, J.H.
2004-04-01
As a first step toward a nonlinear renormalized description of turbulence phenomena in magnetized plasmas, the lowest order quasi-linear description is presented here from a unified point of view for collisionless as well as for collisional plasmas in a constant magnetic field. The quasi-linear approximation is applied to a general kinetic equation obtained previously from the Klimontovich exact equation, by means of a generalised Dupree-Weinstock method. The so-obtained quasi-linear description of electromagnetic turbulence in a magnetoplasma is applied to three separate physical cases: -) weak electrostatic turbulence, -) purely magnetic field fluctuations (the classical quasi-linear results are obtained for cosmic ray diffusion in the 'slab model' of magnetostatic turbulence in the solar wind), and -) collisional kinetic equations of magnetized plasmas. This mathematical technique has allowed us to derive basic kinetic equations for turbulent plasmas and collisional plasmas, respectively in the quasi-linear and Landau approximation. In presence of a magnetic field we have shown that the systematic use of rotation matrices describing the helical particle motion allows for a much more compact derivation than usually performed. Moreover, from the formal analogy between turbulent and collisional plasmas, the results derived here in detail for the turbulent plasmas, can be immediately translated to obtain explicit results for the Landau kinetic equation
Misguich, J.H
2004-04-01
As a first step toward a nonlinear renormalized description of turbulence phenomena in magnetized plasmas, the lowest order quasi-linear description is presented here from a unified point of view for collisionless as well as for collisional plasmas in a constant magnetic field. The quasi-linear approximation is applied to a general kinetic equation obtained previously from the Klimontovich exact equation, by means of a generalised Dupree-Weinstock method. The so-obtained quasi-linear description of electromagnetic turbulence in a magnetoplasma is applied to three separate physical cases: -) weak electrostatic turbulence, -) purely magnetic field fluctuations (the classical quasi-linear results are obtained for cosmic ray diffusion in the 'slab model' of magnetostatic turbulence in the solar wind), and -) collisional kinetic equations of magnetized plasmas. This mathematical technique has allowed us to derive basic kinetic equations for turbulent plasmas and collisional plasmas, respectively in the quasi-linear and Landau approximation. In presence of a magnetic field we have shown that the systematic use of rotation matrices describing the helical particle motion allows for a much more compact derivation than usually performed. Moreover, from the formal analogy between turbulent and collisional plasmas, the results derived here in detail for the turbulent plasmas, can be immediately translated to obtain explicit results for the Landau kinetic equation.
Eck, van H.J.N.; Koppers, W.R.; Rooij, van G.J.; Goedheer, W.J.; Engeln, R.A.H.; Schram, D.C.; Lopes Cardozo, N.J.; Kleyn, A.W.
2009-01-01
The direct simulation Monte Carlo (DSMC) method was used to investigate the efficiency of differential pumping in linear plasma generators operating at high gas flows. Skimmers are used to separate the neutrals from the plasma beam, which is guided from the source to the target by a strong axial
Advanced Thomson scattering system for high-flux linear plasma generator
Meiden, van der H.J.; Lof, A.R.; Berg, van den M.A.; Brons, S.; Donné, A.J.H.; Eck, van H.J.N.; Koelman, Peter; Koppers, W.R.; Kruijt, O.G.; Naumenko, N.N.; Oyevaar, T.; Prins, P.R.; Rapp, J.; Scholten, J.; Schram, D.C.; Smeets, P.H.M.; Star, van der G.; Tugarinov, S.N.; Zeijlmans van Emmichoven, P.A.
2012-01-01
An advanced Thomson scattering system has been built for a linear plasma generator for plasma surface interaction studies. The Thomson scattering system is based on a Nd:YAG laser operating at the second harmonic and a detection branch featuring a high etendue (f /3) transmission grating
Software architecture for control and data acquisition of linear plasma generator Magnum-PSI
Groen, P. W. C.; van Beveren, V.; Broekema, A.; Busch, P. J.; Genuit, J. W.; Kaas, G.; Poelman, A. J.; Scholten, J.; van Emmichoven, P. A. Zeijlma
2013-01-01
The FOM Institute DIFFER – Dutch Institute for Fundamental Energy Research has completed the construction phase of Magnum-PSI, a magnetized, steady-state, large area, high-flux linear plasma beam generator to study plasma surface interactions under ITER divertor conditions. Magnum-PSI consists of
Magnetohydrodynamic motion of a two-fluid plasma
Burby, J. W.
2017-08-01
The two-fluid Maxwell system couples frictionless electrons and ion fluids via Maxwell's equations. When the frequencies of light waves, Langmuir waves, and single-particle cyclotron motion are scaled to be asymptotically large, the two-fluid Maxwell system becomes a fast-slow dynamical system. This fast-slow system admits a formally exact single-fluid closure that may be computed systematically with any desired order of accuracy through the use of a functional partial differential equation. In the leading order approximation, the closure reproduces magnetohydrodynamics (MHD). Higher order truncations of the closure give an infinite hierarchy of extended MHD models that allow for arbitrary mass ratio, as well as perturbative deviations from charge neutrality. The closure is interpreted geometrically as an invariant slow manifold in the infinite-dimensional two-fluid phase space, on which two-fluid motions are free of high-frequency oscillations. This perspective shows that the full closure inherits a Hamiltonian structure from the two-fluid theory. By employing infinite-dimensional Lie transforms, the Poisson bracket for the all-order closure may be obtained in the closed form. Thus, conservative truncations of the single-fluid closure may be obtained by simply truncating the single-fluid Hamiltonian. Moreover, the closed-form expression for the all-order bracket gives explicit expressions for a number of the full closure's conservation laws. Notably, the full closure, as well as any of its Hamiltonian truncations, admits a pair of independent circulation invariants.
Non-Linear Instabilities in an Inhomogeneous Plasma
Coppi, B.; Laval, G.; Pellat, R.; Khiet, Tu
1969-01-01
The low-frequency drift modes of a low-pressure isothermal inhomogeneous plasma can be stabilized if the shear of the magnetic field lines exceeds a critical value given by the expression r/L s = (1/2 √2) (a/r), where L s is the shear length, r the characteristic length of density variation, and a the ion Larmor radius. The authors first show that, even if r/L s [fr
Numerical treatment of linearized equations describing inhomogeneous collisionless plasmas
Lewis, H.R.
1979-01-01
The equations governing the small-signal response of spatially inhomogeneous collisionless plasmas have practical significance in physics, for example in controlled thermonuclear fusion research. Although the solutions are very complicated and the equations are different to solve numerically, effective methods for them are being developed which are applicable when the equilibrium involves only one nonignorable coordinate. The general theoretical framework probably will provide a basis for progress when there are two or three nonignorable coordinates
Electron cyclotron resonance breakdown studies in a linear plasma ...
linear cylindrical system with four different gases – hydrogen, helium, argon and ... The axial magnetic field required for ECR in the system is such that the fundamental .... p being the operating pressure in mbar. λe for various gases at different ...
K. M. Ferrière
2004-01-01
Full Text Available We review the basic approximations underlying magnetohydrodynamic (MHD theory, with special emphasis on the closure approximations, i.e. the approximations used in any fluid approach to close the hierarchy of moment equations. We then present the main closure models that have been constructed for collisionless plasmas in the large-scale regime, and we describe our own mixed MHD-kinetic model, which is designed to study low-frequency linear waves and instabilities in collisionless plasmas. We write down the full dispersion relation in a new, general form, which gathers all the specific features of our MHD-kinetic model into four polytropic indices, and which can be applied to standard adiabatic MHD and to double-adiabatic MHD through a simple change in the expressions of the polytropic indices. We study the mode solutions and the stability properties of the full dispersion relation in each of these three theories, first in the case of a uniform plasma, and then in the case of a stratified plasma. In both cases, we show how the results are affected by the collisionless nature of the plasma.
Simulations of fluid flow through porous media based on cellular automata and non-linear dynamics
Paulson, K V
1992-05-15
A study is being carried out to apply cellular automata and non-linear dynamics in the construction of efficient and accurate computer simulations of multiphase fluid flow through porous media, with the objective of application to reservoir modelling for hydrocarbon recovery. An algorithm based on Boolean operations has been developed which transforms a PC clone into a highly efficient vector processor capable of cellular automata simulation of single fluid flow through two-dimensional rock matrix models of varying porosities. Macroscopic flow patterns have been established through spatial and temporal averaging with no floating point operations. Permeabilities of the different models have been calculated. Hardware allows the algorithm to function on dual processors on a PC platform using a video recording and editing facility. Very encouraging results have been obtained. 4 figs.
Linear Rayleigh-Taylor instability in an accelerated Newtonian fluid with finite width
Piriz, S. A.; Piriz, A. R.; Tahir, N. A.
2018-04-01
The linear theory of Rayleigh-Taylor instability is developed for the case of a viscous fluid layer accelerated by a semi-infinite viscous fluid, considering that the top interface is a free surface. Effects of the surface tensions at both interfaces are taken into account. When viscous effects dominate on surface tensions, an interplay of two mechanisms determines opposite behaviors of the instability growth rate with the thickness of the heavy layer for an Atwood number AT=1 and for sufficiently small values of AT. In the former case, viscosity is a less effective stabilizing mechanism for the thinnest layers. However, the finite thickness of the heavy layer enhances its viscous effects that, in general, prevail on the viscous effects of the semi-infinite medium.
Linear conversion theory on the second harmonic emission from a plasma filament
Tan Weihan; Gu Min
1989-01-01
The linear conversion theory of laser produced plasma filaments is studied. By calculations for the energy flux of the second harmonic emission on the basis of the planar wave-plasma interaction model, it has been found that there exists no 2ω 0 harmonic emission in the direction perpendicular to the incident laser, in contradiction with the experiments. A linear conversion theory is proposed on the second harmonic emission from a plasma filament and discovered the intense 2ω 0 harmonic emission in the direction perpendicular to the incident laser, which is in agreement with the experiments. (author)
Fluid simulations of ∇Te-driven turbulence and transport in boundary plasmas
Xu, X.Q.; Cohen, R.H.
1993-01-01
This paper is a report on simulations of a new drift wave type instability driven by the electron temperature gradient in tokamak scrapeoff-layers (SOL). A 2D(x,y) fluid code has been developed in order to explore the anomalous transport in the boundary plasmas. The simulation consists of a set of fluid equations (in the electrostatic limit) for the vorticity ∇ perpendicular 2 φ, the electron density n e and the temperature T e in a shearless plasma slab confined by a uniform, straight magnetic field B z with two diverter (or limiter) plates intercepting the magnetic field. The model has two regions separated by a magnetic separatrix: in the edge region inside the separatrix, the model is periodic along the magnetic field while in the SOL region outside the separatrix, the magnetic field is taken to be of finite length with model (logical sheath) boundary conditions at diverter (or limiter) plates. The simulation results show that the observed linear instability agrees well with theory, and that a saturated state of turbulence is reached. In saturated turbulence, clear evidence of the expected long-wavelength mode penetration into the edge is seen, an inverse cascade of wave energy (toward both long wavelengths and low frequencies) is observed. The simulation results also show that amplitudes of potential and the electron temperature fluctuations are somewhat above and the heat flux are somewhat below those of the simplest mixing-length estimates. The results from the self-consistent simulations to determine the microturbulent SOL electron temperature profile agree reasonably with the experimental measurements. The effects on the mode of neutral gas collisions at the divertor sheath and comparisons with the ionization driven turbulence are discussed
Non-linear effects and plasma heating by lower-hybrid waves in the Petula tokamak
Briand, P.; Dupas, L.; Golovato, S.N.; Singh, C.M.; Melin, G.; Grelot, P.; Legardeur, R.; Zymanski, S.
1979-01-01
Lower hybrid waves were excited by a two-waveguide 'grill' (nsub(parallel) approximately 1-10, Esub(grill) approximately 3kVcm -1 , Psub(grill) approximately 5kWcm -2 ) at 1.25GHz, 3ms, 600kW. Plasma heating was observed separately as due to non-linear effects alone as well as to a combination of linear and non-linear mechanisms. (author)
Fast non-linear extraction of plasma equilibrium parameters using a neural network mapping
Lister, J.B.; Schnurrenberger, H.
1990-07-01
The shaping of non-circular plasmas requires a non-linear mapping between the measured diagnostic signals and selected equilibrium parameters. The particular configuration of Neural Network known as the multi-layer perceptron provides a powerful and general technique for formulating an arbitrary continuous non-linear multi-dimensional mapping. This technique has been successfully applied to the extraction of equilibrium parameters from measurements of single-null diverted plasmas in the DIII-D tokamak; the results are compared with a purely linear mapping. The method is promising, and hardware implementation is straightforward. (author) 15 refs., 7 figs
Fast non-linear extraction of plasma equilibrium parameters using a neural network mapping
Lister, J.B.; Schnurrenberger, H.
1991-01-01
The shaping of non-circular plasmas requires a non-linear mapping between the measured diagnostic signals and selected equilibrium parameters. The particular configuration of neural network known as the multilayer perceptron provides a powerful and general technique for formulating an arbitrary continuous non-linear multi-dimensional mapping. This technique has been successfully applied to the extraction of equilibrium parameters from measurements of single-null diverted plasmas in the DIII-D tokamak; the results are compared with a purely linear mapping. The method is promising, and hardware implementation is straightforward. (author). 17 refs, 8 figs, 2 tab
Nafari, F.; Yazdani, E.; Malekynia, B.; Ghoranneviss, M.
2010-01-01
Complete text of publication follows. Anomalous interaction of picosecond laser pulses of terawatt to petawatt power is due to suppression of relativistic self-focusing if prepulses are cut-off by a contrast ratio higher than 10 8 . Resulting non-linear ponderomotive forces induced at the skin-layer interaction of a short laser-pulse with a proper preplasma layer produced by the laser prepulse in front of a solid target accelerate two thin (a few μm) quasi-neutral plasma blocks, propagating in forward and backward directions, backward moving against the laser light (ablation) and forward moving into the target. This compressed block produces an ion current density of above 10 11 A/cm 2 . This may support the requirement to produce a fast ignition deuterium tritium fusion at densities not much higher than the solid state by a single shot pw-ps laser pulse. With studying skin-layer subrelativistic interaction of a short (≤ 1 ps) laser pulse with an initial Rayleigh density profile in genuine two-fluid hydrodynamic model, time and spatial distributions of ion block temperature are presented.
Theory of electrostatic fluid modes in a cold spheroidal non-neutral plasma
Dubin, D.H.E.
1991-01-01
The normal modes of a magnetized spheroidally shaped pure ion plasma have recently been measured. Here the theory of these modes is presented. Although one might expect that a numerical solution is required (because the plasma dielectric is anisotropic and the plasma is inhomogeneous), the problem is actually separable in an unusual coordinate system. The result is a simple electrostatic fluid dispersion relation for modes in a cloud of any spheroidal shape
The radioimmunoassay of biologically active compounds in parotid fluid and plasma
Walker, R.F.; Read, G.F.; Riad-Fahmy, D.
1978-01-01
Parotid fluid collection is a simple stress-free procedure. The potential value of parotid fluid estimations of clomipramine, a tricyclic antidepressant, d-norgestrel, a synthetic contraceptive steroid and cortisol have been evaluated for assessment of clinical status and patient compliance. These compounds circulate bound largely to plasma proteins. Their concentration in parotid fluid, which reflects the non-protein bound fraction, is low but assay sensitivity (10, 1 and 30 pg/tube respectively) is adequate. Excellent agreement (r>0.9) was observed when parotid fluid samples were assayed with and without chromatographic purification. Clomipramine levels following oral dosage (150 mg) rose steadily to a maximum in plasma but showed wide fluctuations in parotid fluid. Clomipramine therapy can only be assessed by plasma assays, but patient compliance may be checked by parotid fluid concentrations. Following an oral dose of d-norgestrel (0.3 mg), parotid fluid levels rose steadily to a maximum but plasma response was biphasic making correlation impossible. The sensitivity and high throughput of the d-norgestrel methodology suggests its use in evaluating patient compliance in large-scale fertility control programmes. Changes in circulating cortisol concentrations were rapidly and accurately reflected in parotid fluid in normal volunteers. Parotid fluid cortisol showed a marked diurnal rhythm, suppression to low levels after dexamethasone, and elevation following Synacthen. Low levels after Synacthen stimulation in a patient with secondary adrenal atrophy and constant high levels in Cushingoid patients indicate that parotid fluid cortisol levels could be used for accurate adrenocortical evaluation. The value in rapid screening procedures is stressed since the assay can be performed directly on only 10 μl of parotid fluid. (author)
Welander, A.S.; Deranian, R.D.; Humphreys, D.A.; Leuer, J.A.; Walker, M.L.
2005-01-01
Tokamak control design relies on an accurate linear model of the plasma response, which can often dominate the local field variations in regions under active feedback control. For example, when fluxes at selected points on the plasma boundary are regulated in DIII-D, the plasma response to a change in a coil current gives rise to a flux change which can be larger than and opposite to the flux change caused by the coil alone.In the past, rigid plasma models have been used for linear stability and shape control design. In a rigid model, the plasma current profile is considered fixed and moves rigidly in response to control coils to maintain radial and vertical force balance. In a nonrigid model, however, changes in the plasma shape and current profile are taken into account. Such models are expected to be important for future advanced tokamak control design. The present work describes development of a nonrigid plasma response model for high-accuracy multivariable control design and provides comparisons of model predictions against DIII-D experimental data. The linear perturbed plasma response model is calculated rapidly from an existing equilibrium solution
V. Génot
2009-02-01
Full Text Available Using 5 years of Cluster data, we present a detailed statistical analysis of magnetic fluctuations associated with mirror structures in the magnetosheath. We especially focus on the shape of these fluctuations which, in addition to quasi-sinusoidal forms, also display deep holes and high peaks. The occurrence frequency and the most probable location of the various types of structures is discussed, together with their relation to local plasma parameters. While these properties have previously been correlated to the β of the plasma, we emphasize here the influence of the distance to the linear mirror instability threshold. This enables us to interpret the observations of mirror structures in a stable plasma in terms of bistability and subcritical bifurcation. The data analysis is supplemented by the prediction of a quasi-static anisotropic MHD model and hybrid numerical simulations in an expanding box aimed at mimicking the magnetosheath plasma. This leads us to suggest a scenario for the formation and evolution of mirror structures.
Experimental study of the initial plasma formation stage in a linear theta pinch of inverted field
Casin, G.C.; Alvarez, Ricardo; Rojkind, R.H.; Rodrigo, A.B.
1986-01-01
The initial stage of the plasma formation was studied in a linear theta pinch. Experiments were made to determine the machine operating conditions for good shot-to-shot reproducibility. Spectroscopic measurements of electron density and of electron and ion temperature were made afterwards to characterize the plasma at different stages of its heating process. The results obtained indicate that shot-to-shot reproducibility is strongly influenced by the presence of impurities and by the plasma preionization technique used. Under proper operating conditions, excellent reproducibility was observed. The measured values of the plasma parameters are compatible with those determined for similar machines. (Author) [es
Non-linear unidimensional Debye screening in plasmas
Clemente, R.A.; Martin, P.
1992-01-01
An exact analytical solution for T e = T i and an approximate solution for T e ≠ T i have been obtained for the unidimensional non-linear Debye potential. The approximate expression is a solution of the Poisson equation obtained by expanding up to third order the Boltzmann's factors. The analysis shows that the effective Debye screening length can be quite different from the usual Debye length, when the potential to thermal energy ratio of the particles is not much smaller than unity. (author)
Thermal-Induced Non-linearity of Ag Nano-fluid Prepared using γ-Radiation Method
Esmaeil Shahriari; Wan Mahmood Mat Yunus; Zainal Abidin Talib; Elias Saion
2011-01-01
The non-linear refractive index of Ag nano-fluids prepared by γ-radiation method was investigated using a single beam z-scan technique. Under CW 532 nm laser excitation with power output of 40 mW, the Ag nano-fluids showed a large thermal-induced non-linear refractive index. In the present work it was determined that the non-linear refractive index for Ag nano-fluids is -4.80x10 -8 cm 2 / W. The value of Δn 0 was calculated to be -2.05x10 -4 . Our measurements also confirmed that the non-linear phenomenon was caused by the self-defocusing process making them good candidates for non linear optical devices. (author)
Statistical properties of three-dimensional two-fluid plasma model
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.
Kinetic approach to plasma end loss from linear devices
Dreicer, H.
1976-01-01
A first step in the direction of a kinetic approach to end loss has been presented. This approach brings to light some fundamental processes not uncovered by the magnetohydrodynamic or guiding center approach. Attention was focused on the basically transient phenomenon in a way that describes the quite different behavior of collision dominated and collisionless ions, but ignores the magnetic nozzle effects near the ends of the system. The treatment illuminates some of the roles played by the parameter l/sub ii//L, and suggests the direction for more detailed investigations. End loss from linear systems is a very many faceted problem. Kinetic effects, magnetic effects, heat flow, etc. are all intermixed, and it will require a strong long term experimental and theoretical program to unravel all of its mysteries
Pranger, Arianna D; Alffenaar, Jan-Willem C; Wessels, A Mireille A; Greijdanus, Ben; Uges, Donald R A
2010-04-01
Moxifloxacin (MFX) is a useful agent in the treatment of multi-drug-resistant tuberculosis (MDR-TB). At Tuberculosis Centre Beatrixoord, a referral center for tuberculosis in the Netherlands, approximately 36% of the patients have received MFX as treatment. Based on the variability of MFX AUC, the variability of in vitro susceptibility to MFX of M. tuberculosis, and the variability of penetration into sanctuary sites, measuring the concentration of MFX in plasma and cerebrospinal fluid (CSF) could be recommended. Therefore, a rapid and validated liquid chromatography-tandem mass spectrometry (LC-MS-MS) analyzing method with a simple pretreatment procedure was developed for therapeutic drug monitoring of MFX in human plasma and CSF. Because of the potential influence of protein binding on efficacy, we decided to determine both bound and unbound (ultrafiltrate) fraction of MFX. The calibration curves were linear in the therapeutic range of 0.05 to 5.0 mg/L plasma and CSF with CV in the range of -5.4% to 9.3%. MFX ultrafiltrate samples could be determined with the same method setup for analysis of MFX in CSF. The LC-MS-MS method developed in this study is suitable for monitoring MFX in human plasma, plasma ultrafiltrate, and CSF.
Sankararaman, Sumithra; Menon, Gautam I; Sunil Kumar, P B
2002-09-01
We study the linearized hydrodynamics of a two-component fluid membrane near a repulsive wall, using a model that incorporates curvature-concentration coupling as well as hydrodynamic interactions. This model is a simplified version of a recently proposed one [J.-B. Manneville et al., Phys. Rev. E 64, 021908 (2001)] for nonequilibrium force centers embedded in fluid membranes, such as light-activated bacteriorhodopsin pumps incorporated in phospholipid egg phosphatidyl choline (EPC) bilayers. The pump-membrane system is modeled as an impermeable, two-component bilayer fluid membrane in the presence of an ambient solvent, in which one component, representing active pumps, is described in terms of force dipoles displaced with respect to the bilayer midpoint. We first discuss the case in which such pumps are rendered inactive, computing the mode structure in the bulk as well as the modification of hydrodynamic properties by the presence of a nearby wall. These results should apply, more generally, to equilibrium fluid membranes comprised of two components, in which the effects of curvature-concentration coupling are significant, above the threshold for phase separation. We then discuss the fluctuations and mode structure in the steady state of active two-component membranes near a repulsive wall. We find that proximity to the wall smoothens membrane height fluctuations in the stable regime, resulting in a logarithmic scaling of the roughness even for initially tensionless membranes. This explicitly nonequilibrium result is a consequence of the incorporation of curvature-concentration coupling in our hydrodynamic treatment. This result also indicates that earlier scaling arguments which obtained an increase in the roughness of active membranes near repulsive walls upon neglecting the role played by such couplings may need to be reevaluated.
Generation of zonal flows in rotating fluids and magnetized plasmas
Juul Rasmussen, J.; Garcia, O.E.; Naulin, V.
2006-01-01
The spontaneous generation of large-scale flows by the rectification of small-scale turbulent fluctuations is of great importance both in geophysical flows and in magnetically confined plasmas. These flows regulate the turbulence and may set up effective transport barriers. In the present....... The analogy to large-scale flow generation in drift-wave turbulence dynamics in magnetized plasma is briefly discussed....
Linear and nonlinear electrostatic modes in a nonuniform magnetized electron plasma
Vranjes, J.; Shukla, P.K.; Kono, M.; Poedts, S.
2001-01-01
Linear and nonlinear low-frequency modes in a magnetized electron plasma are studied, taking into account a proper description of the equilibrium plasma state that is inhomogeneous. Assuming a homogeneous magnetic field and sheared plasma flows, flute-like perturbations are studied in the presence of density and potential gradients. Linear analysis reveals the presence of a streaming instability and depicts conditions for global linear spiral mode. In the nonlinear domain, a tripolar vortex, which is driven and carried by the flow, is found. Also investigated are the consequences of a magnetic shear as well as nonuniformities along the magnetic field lines, which are shown to be responsible for the possible annulment of the magnetic shear effects. Streaming along the lines of the sheared magnetic field is also studied. A variety of nonlinear structures (viz. global multipolar vortices, local vortex chains, and tripolar vortices) is shown to be the consequence of the simultaneous action of the parallel and perpendicular flows
ALFVÉN WAVES IN A PARTIALLY IONIZED TWO-FLUID PLASMA
Soler, R.; Ballester, J. L.; Terradas, J.; Carbonell, M.
2013-01-01
Alfvén waves are a particular class of magnetohydrodynamic waves relevant in many astrophysical and laboratory plasmas. In partially ionized plasmas the dynamics of Alfvén waves is affected by the interaction between ionized and neutral species. Here we study Alfvén waves in a partially ionized plasma from the theoretical point of view using the two-fluid description. We consider that the plasma is composed of an ion-electron fluid and a neutral fluid, which interact by means of particle collisions. To keep our investigation as general as possible, we take the neutral-ion collision frequency and the ionization degree as free parameters. First, we perform a normal mode analysis. We find the modification due to neutral-ion collisions of the wave frequencies and study the temporal and spatial attenuation of the waves. In addition, we discuss the presence of cutoff values of the wavelength that constrain the existence of oscillatory standing waves in weakly ionized plasmas. Later, we go beyond the normal mode approach and solve the initial-value problem in order to study the time-dependent evolution of the wave perturbations in the two fluids. An application to Alfvén waves in the low solar atmospheric plasma is performed and the implication of partial ionization for the energy flux is discussed.
Liu, Haiping; Wang, Jianye; Wang, Haiyu; Tang, Ning; Li, Yunfei; Zhang, Yan; Hao, Tianyu
2016-09-01
Enzyme matrix metalloproteinase-9 is a member of the matrix metalloproteinase family, which is critical to normal tissue remodelling during embryogenesis and wound healing. In patients with endometriosis, increased expression and activity of matrix metalloproteinase-9 have been observed in ectopic endometrium, but the plasma and peritoneal fluid concentrations of matrix metalloproteinase-9 in patients with endometriosis and their relation to disease severity have not been clear. The aim of the study was to investigate the concentrations of matrix metalloproteinase-9 in plasma and peritoneal fluid of patients with endometriosis. A prospective case-control study was conducted in Jinan Military General Hospital between January 2010 and December 2013. Fifty patients with proven endometriosis and 26 endometriosis-free controls were enrolled in this study. Patients with endometriosis were evaluated and divided into moderate/severe endometriosis group (stage I-II, n = 26) and minimal/mild endometriosis group (stage III-IV, n = 24) according to the revised criteria of the American Society for Reproductive Medicine. Blood samples and peritoneal fluid were obtained from both patients and controls. Matrix metalloproteinase-9 was measured using enzyme-linked immunosorbent assay in plasma and peritoneal fluid. The concentration of matrix metalloproteinase-9 between different groups was compared and its correlation to disease severity was analysed. Plasma and peritoneal fluid concentrations of matrix metalloproteinase-9 in patients with endometriosis were higher than that in controls. In addition, those patients with moderate/severe endometriosis had significantly higher plasma and peritoneal fluid concentrations of matrix metalloproteinase-9 compared to those with minimal/mild endometriosis. Matrix metalloproteinase-9 concentrations in plasma and peritoneal fluid were both positively correlated with severity of endometriosis and plasma matrix metalloproteinase-9
Linear electrostatic waves in a three-component electron-positron-ion plasma
Mugemana, A., E-mail: mugemanaa@gmail.com; Moolla, S. [School of Chemistry and Physics, University of KwaZulu-Natal, Durban 4000 (South Africa); Lazarus, I. J. [Department of Mathematics, Statistics and Physics, Durban University of Technology, Durban 4000 (South Africa)
2014-12-15
Analytical linear electrostatic waves in a magnetized three-component electron-positron-ion plasma are studied in the low-frequency limit. By using the continuity and momentum equations with Poisson's equation, the dispersion relation for the electron-positron-ion plasma consisting of cool ions, and hot Boltzmann electrons and positrons is derived. In the linear regime, the propagation of two possible modes and their evolution are studied. In the cases of parallel and perpendicular propagation, it is shown that these two possible modes are always stable. The present investigation contributes to nonlinear propagation of electrostatic waves in space and the laboratory.
Numerical linear algebra on emerging architectures: The PLASMA and MAGMA projects
Agullo, Emmanuel; Demmel, Jim; Dongarra, Jack; Hadri, Bilel; Kurzak, Jakub; Langou, Julien; Ltaief, Hatem; Luszczek, Piotr; Tomov, Stanimire
2009-01-01
The emergence and continuing use of multi-core architectures and graphics processing units require changes in the existing software and sometimes even a redesign of the established algorithms in order to take advantage of now prevailing parallelism. Parallel Linear Algebra for Scalable Multi-core Architectures (PLASMA) and Matrix Algebra on GPU and Multics Architectures (MAGMA) are two projects that aims to achieve high performance and portability across a wide range of multi-core architectures and hybrid systems respectively. We present in this document a comparative study of PLASMA's performance against established linear algebra packages and some preliminary results of MAGMA on hybrid multi-core and GPU systems.
Plasma resistance behavior during the linear decay phase of RFPs in ETA BETA II
Nalesso, G.F.
1982-01-01
In the aided-reversal mode RFP discharges produced in ETA BETA II, the plasma current is characterized by a linear decay phase, which follows an approximately exponential phase. During the same period the measured toroidal voltage is negative and initially increasing in absolute value (exponential phase) and then decreasing to almost zero during the linear phase before the current termination. The same behavior of the current has been observed in the quiescent phase in Zeta where a negative toroidal electric field was also observed. In this note we present a model that can explain the linear decay phase and fits with the experimental parameters and allows us to estimate the plasma resistance behavior during the linear phase of slow reversed field pinch discharges
The radioimmunoassay of biologically active compounds in parotid fluid and plasma
Walker, R.F.; Read, G.F.; Riad-Fahmy, D.
1977-01-01
The potential value of parotid fluid estimations of clomipramine, d-norgestrel, and cortisol have been evaluated for assessment of clinical status and patient compliance. Excellent agreement (r > 0.9) was observed when parotid fluid samples were assayed with and without chromatographic purification. Clomipramine levels following oral dosage (150mg) rose steadily to a maximum in plasma but showed wide fluctuations in parotid fluid. Following an oral dose of d-norgestrel(0.3mg), parotid fluid levels rose steadily to a maximum but plasma response was biphasic making correlation impossible. The sensitivity and high throughput of the d-norgestrel methodology suggests its use in evaluating patient compliance in large scale fertility control programmes. Changes in circulating cortisol concentrations were rapidly and accurately reflected in parotid fluid in normal volunteers. Parotid fluid cortisol showed a market diurnal rythm, suppression to low levels after dexamethasone, and elevation following Synacthen. Low levels after Synacthen stimulation in a patient with secondary adrenal atrophy and constant high levels in Cushingoid patients indicate that parotid fluid cortisol levels could be used for accurate adrenocortical evaluation. The value in rapid screening procedures is stressed since the assay can be performed directly on only 10μl of parotid fluid. (orig./AJ) [de
Analytical approach to linear fractional partial differential equations arising in fluid mechanics
Momani, Shaher; Odibat, Zaid
2006-01-01
In this Letter, we implement relatively new analytical techniques, the variational iteration method and the Adomian decomposition method, for solving linear fractional partial differential equations arising in fluid mechanics. The fractional derivatives are described in the Caputo sense. The two methods in applied mathematics can be used as alternative methods for obtaining analytic and approximate solutions for different types of fractional differential equations. In these methods, the solution takes the form of a convergent series with easily computable components. The corresponding solutions of the integer order equations are found to follow as special cases of those of fractional order equations. Some numerical examples are presented to illustrate the efficiency and reliability of the two methods
Linear theory of a cold relativistic beam in a strongly magnetized finite-geometry plasma
Gagne, R.R.J.; Shoucri, M.M.
1976-01-01
The linear theory of a finite-geometry cold relativistic beam propagating in a cold homogeneous finite-geometry plasma, is investigated in the case of a strongly magnetized plasma. The beam is assumed to propagate parallel to the external magnetic field. It is shown that the instability which takes place at the Cherenkov resonance ωapprox. =k/subz/v/subb/ is of the convective type. The effect of the finite geometry on the instability growth rate is studied and is shown to decrease the growth rate, with respect to the infinite geometry, by a factor depending on the ratio of the beam-to-plasma radius
Multidimensional Plasma Wake Excitation in the Non-linear Blowout Regime
Vieira, J.; Silva, L.O.
2016-01-01
Plasma accelerators can sustain very high acceleration gradients. They are promising candidates for future generations of particle accelerators for sev- eral scientific, medical and technological applications. Current plasma based acceleration experiments operate in the relativistic regime, where the plasma response is strongly non-linear. We outline some of the key properties of wake- field excitation in these regimes. We outline a multidimensional theory for the excitation of plasma wakefields in connection with current experiments. We then use these results and provide design guidelines for the choice of laser and plasma parameters ensuring a stable laser wakefield accelerator that maximizes the quality of the accelerated electrons. We also mention some of the future challenges associated with this technology.
Characterization of high flux magnetized helium plasma in SCU-PSI linear device
Xiaochun, MA; Xiaogang, CAO; Lei, HAN; Zhiyan, ZHANG; Jianjun, WEI; Fujun, GOU
2018-02-01
A high-flux linear plasma device in Sichuan University plasma-surface interaction (SCU-PSI) based on a cascaded arc source has been established to simulate the interactions between helium and hydrogen plasma with the plasma-facing components in fusion reactors. In this paper, the helium plasma has been characterized by a double-pin Langmuir probe. The results show that the stable helium plasma beam with a diameter of 26 mm was constrained very well at a magnetic field strength of 0.3 T. The core density and ion flux of helium plasma have a strong dependence on the applied current, magnetic field strength and gas flow rate. It could reach an electron density of 1.2 × 1019 m-3 and helium ion flux of 3.2 × 1022 m-2 s-1, with a gas flow rate of 4 standard liter per minute, magnetic field strength of 0.2 T and input power of 11 kW. With the addition of -80 V applied to the target to increase the helium ion energy and the exposure time of 2 h, the flat top temperature reached about 530 °C. The different sizes of nanostructured fuzz on irradiated tungsten and molybdenum samples surfaces under the bombardment of helium ions were observed by scanning electron microscopy. These results measured in the SCU-PSI linear device provide a reference for International Thermonuclear Experimental Reactor related PSI research.
Lazar, M.; Schlickeiser, R.
2006-01-01
The properties of transverse waves parallel propagating in magnetized plasmas with arbitrary composition and thermally anisotropic, are investigated on the basis of relativistic Vlasov-Maxwell equations. The transverse dispersion relations for plasmas with arbitrary distribution functions are derived. These dispersion relations describe the linear response of the system to the initial perturbations and thus define all existing linear (transverse) plasma modes in the system. By analytic continuation the dispersion relations in the whole complex frequency plane are constructed. Further analysis is restricted to the important case of anisotropic bi-Maxwellian equilibrium plasma distribution functions. Explicit forms of the relativistically correct transverse dispersion relations are derived that hold for any values of the plasma temperatures and the temperature anisotropy. In the limit of nonrelativistic plasma temperatures the dispersion relations are expressed in terms of plasma dispersion function, however, the dependence on frequency and wave numbers is markedly different from the standard noncovariant nonrelativistic analysis. Only in the strictly unphysical formal limit of an infinitely large speed of light, c→∞, does the nonrelativistic dispersion relations reduce to the standard noncovariant dispersion relations
Characterization of the porcine synovial fluid proteome and a comparison to the plasma proteome
Bennike, Tue Bjerg; Barnaby, Omar; Steen, Hanno
2015-01-01
Synovial fluid is present in all joint cavities, and protects the articular cartilage surfaces in large by lubricating the joint, thus reducing friction. Several studies have described changes in the protein composition of synovial fluid in patients with joint disease. However, the protein concen...... data used in the method optimization, human plasma proteomics data, and search results, have been deposited to the ProteomeXchange Consortium via the PRIDE partner repository with the dataset identifier PXD000935....
Plasma-treated carbonyl iron particles as a dispersed phase in magnetorheological fluids
Sedlačík, M.; Pavlínek, V.; Lehocký, M.; Mráček, A.; Grulich, O.; Švrčinová, Petra; Filip, Petr; Vesel, A.
2011-01-01
Roč. 387, 1-3 (2011), s. 99-103 ISSN 0927-7757 Grant - others:GA ČR(CZ) GD104/09/H080; OP VaVpI(XE) CZ.1.05/2.1.00/03.0111 Program:GD Institutional research plan: CEZ:AV0Z20600510 Keywords : carbonyl iron * magnetorheological fluid * plasma * viscoelasticity Subject RIV: BK - Fluid Dynamics Impact factor: 2.236, year: 2011
Validation of Numerical Two-Fluid and Kinetic Plasma Models
Daniel Barnes
2011-03-25
This was a four year grant commencing October 1, 2003 and finishing September 30, 2007. The funding was primarily used to support the work of the Principal Investigator, who collaborated with Profs. Scott Parker and John Cary at U. Colorado, and with two students, N. Xiang and J. Cheng also of U. Colorado. The technical accomplishments of this grant can be found in the publications listed in the final Section here. The main accomplishments of the grant work were: (1) Development and implementation of time-implicit two-fluid simulation methods in collaboration with the NIMROD team; and (2) Development and testing of a new time-implicit delta-f, energy-conserving method The basic two-fluid method, with many improvements is used in present NIMROD calculations. The energy-conserving delta-f method is under continuing development under contract between Coronado Consulting, a New Mexico sole proprietorship and the Oak Ridge National Laboratory.
Schekochihin, A. A.; Cowley, S. C.; Dorland, W.; Hammett, G. W.; Howes, G. G.; Quataert, E.; Tatsuno, T.
2009-04-23
This paper presents a theoretical framework for understanding plasma turbulence in astrophysical plasmas. It is motivated by observations of electromagnetic and density fluctuations in the solar wind, interstellar medium and galaxy clusters, as well as by models of particle heating in accretion disks. All of these plasmas and many others have turbulentmotions at weakly collisional and collisionless scales. The paper focuses on turbulence in a strong mean magnetic field. The key assumptions are that the turbulent fluctuations are small compared to the mean field, spatially anisotropic with respect to it and that their frequency is low compared to the ion cyclotron frequency. The turbulence is assumed to be forced at some system-specific outer scale. The energy injected at this scale has to be dissipated into heat, which ultimately cannot be accomplished without collisions. A kinetic cascade develops that brings the energy to collisional scales both in space and velocity. The nature of the kinetic cascade in various scale ranges depends on the physics of plasma fluctuations that exist there. There are four special scales that separate physically distinct regimes: the electron and ion gyroscales, the mean free path and the electron diffusion scale. In each of the scale ranges separated by these scales, the fully kinetic problem is systematically reduced to a more physically transparent and computationally tractable system of equations, which are derived in a rigorous way. In the "inertial range" above the ion gyroscale, the kinetic cascade separates into two parts: a cascade of Alfvenic fluctuations and a passive cascade of density and magnetic-fieldstrength fluctuations. The former are governed by the Reduced Magnetohydrodynamic (RMHD) equations at both the collisional and collisionless scales; the latter obey a linear kinetic equation along the (moving) field lines associated with the Alfvenic component (in the collisional limit, these compressive fluctuations
Schekochihin, A.A.; Cowley, S.C.; Dorland, W.; Hammett, G.W.; Howes, G.G.; Quataert, E.; Tatsuno, T.
2009-01-01
This paper presents a theoretical framework for understanding plasma turbulence in astrophysical plasmas. It is motivated by observations of electromagnetic and density fluctuations in the solar wind, interstellar medium and galaxy clusters, as well as by models of particle heating in accretion disks. All of these plasmas and many others have turbulent motions at weakly collisional and collisionless scales. The paper focuses on turbulence in a strong mean magnetic field. The key assumptions are that the turbulent fluctuations are small compared to the mean field, spatially anisotropic with respect to it and that their frequency is low compared to the ion cyclotron frequency. The turbulence is assumed to be forced at some system-specific outer scale. The energy injected at this scale has to be dissipated into heat, which ultimately cannot be accomplished without collisions. A kinetic cascade develops that brings the energy to collisional scales both in space and velocity. The nature of the kinetic cascade in various scale ranges depends on the physics of plasma fluctuations that exist there. There are four special scales that separate physically distinct regimes: the electron and ion gyroscales, the mean free path and the electron diffusion scale. In each of the scale ranges separated by these scales, the fully kinetic problem is systematically reduced to a more physically transparent and computationally tractable system of equations, which are derived in a rigorous way. In the 'inertial range' above the ion gyroscale, the kinetic cascade separates into two parts: a cascade of Alfvenic fluctuations and a passive cascade of density and magnetic-field strength fluctuations. The former are governed by the Reduced Magnetohydrodynamic (RMHD) equations at both the collisional and collisionless scales; the latter obey a linear kinetic equation along the (moving) field lines associated with the Alfvenic component (in the collisional limit, these compressive fluctuations
How to assess the plasma delivery of RONS into tissue fluid and tissue
Oh, Jun-Seok; Szili, Endre J.; Gaur, Nishtha; Hong, Sung-Ha; Furuta, Hiroshi; Kurita, Hirofumi; Mizuno, Akira; Hatta, Akimitsu; Short, Robert D.
2016-08-01
The efficacy of helium (He) and argon (Ar) plasma jets are being investigated for different healthcare applications including wound and cancer therapy, sterilisation and surface disinfections. Current research points to a potential link between the generation of reactive oxygen and nitrogen species (RONS) and outcomes in a range of biological and medical applications. As new data accrue, further strengthening this link, it becomes important to understand the controlled delivery of RONS into solutions, tissue fluids and tissues. This paper investigates the use of He and Ar plasma jets to deliver three RONS (hydrogen peroxide—H2O2, nitrite—\\text{NO}2- and nitrate—\\text{NO}3- ) and molecular oxygen (O2) directly into deionised (DI) water, or indirectly into DI water through an agarose target. The DI water is used in place of tissue fluid and the agarose target serves as a surrogate of tissue. Direct plasma jet treatments deliver more RONS and O2 than the through-agarose treatments for equivalent treatments times. The former only deliver RONS whilst the plasma jets are ignited; the latter continues to deliver RONS into the DI water long after the plasmas are extinguished. The He plasma jet is more effective at delivering H2O2 and \\text{NO}2- directly into DI water, but the Ar plasma jet is more effective at nitrating the DI water in both direct and through-agarose treatments. DI water directly treated with the plasma jets is deoxygenated, with the He plasma jet purging more O2 than the Ar plasma jet. This effect is known as ‘sparging’. In contrast, for through-agarose treatments both jets oxygenated the DI water. These results indicate that in the context of direct and indirect plasma jet treatments of real tissue fluids and tissue, the choice of process gas (He or Ar) could have a profound effect on the concentrations of RONS and O2. Irrespective of operating gas, sparging of tissue fluid (in an open wound) for long prolonged periods during direct plasma
Generalized Hamiltonians, functional integration and statistics of continuous fluids and plasmas
Tasso, H.
1985-05-01
Generalized Hamiltonian formalism including generalized Poisson brackets and Lie-Poisson brackets is presented in Section II. Gyroviscous magnetohydrodynamics is treated as a relevant example in Euler and Clebsch variables. Section III is devoted to a short review of functional integration containing the definition and a discussion of ambiguities and methods of evaluation. The main part of the contribution is given in Section IV, where some of the content of the previous sections is applied to Gibbs statistics of continuous fluids and plasmas. In particular, exact fluctuation spectra are calculated for relevant equations in fluids and plasmas. (orig.)
Interstellar turbulence model : A self-consistent coupling of plasma and neutral fluids
Shaikh, Dastgeer; Zank, Gary P.; Pogorelov, Nikolai
2006-01-01
We present results of a preliminary investigation of interstellar turbulence based on a self-consistent two-dimensional fluid simulation model. Our model describes a partially ionized magnetofluid interstellar medium (ISM) that couples a neutral hydrogen fluid to a plasma through charge exchange interactions and assumes that the ISM turbulent correlation scales are much bigger than the shock characteristic length-scales, but smaller than the charge exchange mean free path length-scales. The shocks have no influence on the ISM turbulent fluctuations. We find that nonlinear interactions in coupled plasma-neutral ISM turbulence are influenced substantially by charge exchange processes
Viriato: a Fourier-Hermite spectral code for strongly magnetised fluid-kinetic plasma dynamics
Loureiro, Nuno; Dorland, William; Fazendeiro, Luis; Kanekar, Anjor; Mallet, Alfred; Zocco, Alessandro
2015-11-01
We report on the algorithms and numerical methods used in Viriato, a novel fluid-kinetic code that solves two distinct sets of equations: (i) the Kinetic Reduced Electron Heating Model equations [Zocco & Schekochihin, 2011] and (ii) the kinetic reduced MHD (KRMHD) equations [Schekochihin et al., 2009]. Two main applications of these equations are magnetised (Alfvnénic) plasma turbulence and magnetic reconnection. Viriato uses operator splitting to separate the dynamics parallel and perpendicular to the ambient magnetic field (assumed strong). Along the magnetic field, Viriato allows for either a second-order accurate MacCormack method or, for higher accuracy, a spectral-like scheme. Perpendicular to the field Viriato is pseudo-spectral, and the time integration is performed by means of an iterative predictor-corrector scheme. In addition, a distinctive feature of Viriato is its spectral representation of the parallel velocity-space dependence, achieved by means of a Hermite representation of the perturbed distribution function. A series of linear and nonlinear benchmarks and tests are presented, with focus on 3D decaying kinetic turbulence. Work partially supported by Fundação para a Ciência e Tecnologia via Grants UID/FIS/50010/2013 and IF/00530/2013.
Cros, Brigitte
1989-01-01
This research thesis reports the study of the non linear evolution of plasma waves excited by mode conversion in a non homogeneous, non collisional, and free-of-external-magnetic-field plasma. Experiments performed in the microwave domain in a plasma created by means of a multi-polar device show that the evolution of plasma waves displays a transition between a non linear quasi-steady regime and a stochastic regime when the power of incident electromagnetic waves or plasma gradient length is increased. These regimes are characterized through a numerical resolution of Zakharov equations which describe the coupled evolution of plasma wave envelope and low frequency density perturbations [fr
Adams, Allan; Carr, Lincoln D.; Schafer, Thomas; Steinberg, Peter; Thomas, John E.
2012-01-01
Strongly correlated quantum fluids are phases of matter that are intrinsically quantum mechanical, and that do not have a simple description in terms of weakly interacting quasi-particles. Two systems that have recently attracted a great deal of interest are the quark-gluon plasma, a plasma of strongly interacting quarks and gluons produced in relativistic heavy ion collisions, and ultracold atomic Fermi gases, very dilute clouds of atomic gases confined in optical or magnetic traps. These sy...
Fluid description of particle transport in hf heated magnetized plasma
Klima, R.
1980-01-01
Particle fluxes averaged over high-frequency oscillations are analyzed. The collisional effects and the kinetic mechanisms of energy absorption are included. Spatial dependences of both the high-frequency and the (quasi-)steady electromagnetic fields are arbitrary. The equations governing the fluxes are deduced from the moments of the averaged kinetic equation. Explicit expressions for steady state fluxes are given in terms of electromagnetic field quantities. The results can also be applied to anomalous transport phenomena in weakly turbulent plasmas. (author)
Ion-acoustic cnoidal wave and associated non-linear ion flux in dusty plasma
Jain, S. L. [Poornima Group of Institution, Sitapura, Jaipur 302022 (India); Tiwari, R. S. [Regional College for Education, Research and Technology, Jaipur 302022 (India); Mishra, M. K. [Department of Physics, University of Rajasthan, Jaipur 302004 (India)
2012-10-15
Using reductive perturbation method with appropriate boundary conditions, coupled evolution equations for first and second order potentials are derived for ion-acoustic waves in a collisionless, un-magnetized plasma consisting of hot isothermal electrons, cold ions, and massive mobile charged dust grains. The boundary conditions give rise to renormalization term, which enable us to eliminate secular contribution in higher order terms. Determining the non secular solution of these coupled equations, expressions for wave phase velocity and averaged non-linear ion flux associated with ion-acoustic cnoidal wave are obtained. Variation of the wave phase velocity and averaged non-linear ion flux as a function of modulus (k{sup 2}) dependent wave amplitude are numerically examined for different values of dust concentration, charge on dust grains, and mass ratio of dust grains with plasma ions. It is found that for a given amplitude, the presence of positively (negatively) charged dust grains in plasma decreases (increases) the wave phase velocity. This behavior is more pronounced with increase in dust concentrations or increase in charge on dust grains or decrease in mass ratio of dust grains. The averaged non-linear ion flux associated with wave is positive (negative) for negatively (positively) charged dust grains in the plasma and increases (decreases) with modulus (k{sup 2}) dependent wave amplitude. For given amplitude, it increases (decreases) as dust concentration or charge of negatively (positively) charged dust grains increases in the plasma.
Fusco, D [Messina Univ. (Italy). Instituto de Matematica
1979-01-01
The paper is concerned with a three-dimensional theory of non-linear magnetosonic waves in a turbulent plasma. A perturbation method is used that allows a transport equation, like Burgers equation but with a variable coefficient to be obtained.
A Revised Piecewise Linear Recursive Convolution FDTD Method for Magnetized Plasmas
Liu Song; Zhong Shuangying; Liu Shaobin
2005-01-01
The piecewise linear recursive convolution (PLRC) finite-different time-domain (FDTD) method improves accuracy over the original recursive convolution (RC) FDTD approach and current density convolution (JEC) but retains their advantages in speed and efficiency. This paper describes a revised piecewise linear recursive convolution PLRC-FDTD formulation for magnetized plasma which incorporates both anisotropy and frequency dispersion at the same time, enabling the transient analysis of magnetized plasma media. The technique is illustrated by numerical simulations of the reflection and transmission coefficients through a magnetized plasma layer. The results show that the revised PLRC-FDTD method has improved the accuracy over the original RC FDTD method and JEC FDTD method
Non linear excitation of waves at the vicinity of plasma resonance
Chiron, Arnaud
1992-01-01
This research thesis reports the study of the non linear evolution of ionic acoustic and plasma waves excited by resonant absorption of an electromagnetic wave, in a non collisional plasma, without external magnetic field, and with a parabolic density profile. The plasma resonance occurs about the density profile peak. The numerical resolution of the Zakharov equation system is performed to describe the coupled evolution of the plasma wave electric field envelope, and low frequency density disturbances. Experiments performed in the microwave domain show the existence of a new effect related to the modification of the electromagnetic wave propagation under the influence of plasma density disturbances created by the ponderomotive force. This effect which results in a collisional relaxation of plasma waves trapped in the cavity formed at resonance, cannot be taken into account by a numerical simulation using a capacitive pump field. Measurements showed that plasma waves were trapped and relaxing in a cavity with characteristic dimensions of some thousands of Debye lengths, and that the plasma wave in the cavity was stationary. A new turbulence regime is thus highlighted [fr
Ion acoustic waves in pair-ion plasma: Linear and nonlinear analyses
Saeed, R.; Mushtaq, A.
2009-01-01
Linear and nonlinear properties of low frequency ion acoustic wave (IAW) in pair-ion plasma in the presence of electrons are investigated. The dispersion relation and Kadomtsev-Petviashvili equation for linear/nonlinear IAW are derived from sets of hydrodynamic equations where the ion pairs are inertial while electrons are Boltzmannian. The dispersion curves for various concentrations of electrons are discussed and compared with experimental results. The predicted linear IAW propagates at the same frequencies as those of the experimentally observed IAW if n e0 ∼10 4 cm -3 . It is found that nonlinear profile of the ion acoustic solitary waves is significantly affected by the percentage ratio of electron number density and temperature. It is also determined that rarefactive solitary waves can propagate in this system. It is hoped that the results presented in this study would be helpful in understanding the salient features of the finite amplitude localized ion acoustic solitary pulses in a laboratory fullerene plasma.
Shaing, K. C.
2007-01-01
In Part I [Phys. Fluids B 2, 1190 (1990)] and Part II [Phys. Plasmas 12, 082508 (2005)], it was emphasized that the equilibrium plasma viscous forces when applied for the magnetohydrodynamic (MHD) modes are only rigorously valid at the mode rational surface where m-nq=0. Here, m is the poloidal mode number, n is the toroidal mode number, and q is the safety factor. This important fact has been demonstrated explicitly by calculating the viscous forces in the plateau regime in Parts I and II. Here, the effective viscous forces in the banana regime are calculated for MHD modes by solving the linear drift kinetic equation that is driven by the plasma flows first derived in Part I. At the mode rational surface, the equilibrium plasma viscous forces are reproduced. However, it is found that away from the mode rational surface, the viscous forces for MHD modes decrease, a behavior similar to that observed in the viscous forces for the plateau regime. The proper form of the momentum equation that is appropriate for the modeling of the MHD modes is also discussed
Yeh, Hsin-Hua; Yang, Yuan-Han; Ko, Ju-Yun; Chen, Su-Hwei
2006-07-07
A simple micellar electrokinetic chromatography (MEKC) method with UV detection at 200 nm for analysis of piracetam in plasma and in cerebrospinal fluid (CSF) by direct injection without any sample pretreatment is described. The separation of piracetam from biological matrix was performed at 25 degrees C using a background electrolyte consisting of Tris buffer with sodium dodecyl sulfate (SDS) as the electrolyte solution. Several parameters affecting the separation of the drug from biological matrix were studied, including the pH and concentrations of the Tris buffer and SDS. Under optimal MEKC condition, good separation with high efficiency and short analyses time is achieved. Using imidazole as an internal standard (IS), the linear ranges of the method for the determination of piracetam in plasma and in CSF were all between 5 and 500 microg/mL; the detection limit of the drug in plasma and in CSF (signal-to-noise ratio=3; injection 0.5 psi, 5s) was 1.0 microg/mL. The applicability of the proposed method for determination of piracetam in plasma and CSF collected after intravenous administration of 3g piracetam every 6h and oral administration 1.2g every 6h in encephalopathy patients with aphasia was demonstrated.
A new linear plasma device for the study of plasma waves in the ...
Garima Joshi
2018-05-16
May 16, 2018 ... magnetic field by Helmholtz coils, both designed and constructed in-house. The plasma .... Vacuum-compatible permanent mag- nets (NdFeB) are ..... ing of the stepper is decided by the motor driver which is controlled by a ...
Richtmyer–Meshkov instability of a thermal interface in a two-fluid plasma
Bond, D.; Wheatley, V.; Samtaney, Ravi; Pullin, D. I.
2017-01-01
We computationally investigate the Richtmyer–Meshkov instability of a density interface with a single-mode perturbation in a two-fluid, ion–electron plasma with no initial magnetic field. Self-generated magnetic fields arise subsequently. We study
Ertel's vorticity theorem and new flux surfaces in multi-fluid plasmas
Hameiri, Eliezer
2013-01-01
Dedicated to Professor Harold Weitzner on the occasion of his retirement“Say to wisdom ‘you are my sister,’ and to insight ‘you are my relative.’”—Proverbs 7:4Based on an extension to plasmas of Ertel's classical vorticity theorem in fluid dynamics, it is shown that for each species in a multi-fluid plasma there can be constructed a set of nested surfaces that have this species' fluid particles confined within them. Variational formulations for the plasma evolution and its equilibrium states are developed, based on the new surfaces and all of the dynamical conservation laws associated with them. It is shown that in the general equilibrium case, the energy principle lacks a minimum and cannot be used as a stability criterion. A limit of the variational integral yields the two-fluid Hall-magnetohydrodynamic (MHD) model. A further special limit yields MHD equilibria and can be used to approximate the equilibrium state of a Hall-MHD plasma in a perturbative way
Low-impedance internal linear inductive antenna for large-area flat panel display plasma processing
Kim, K.N.; Jung, S.J.; Lee, Y.J.; Yeom, G.Y.; Lee, S.H.; Lee, J.K.
2005-01-01
An internal-type linear inductive antenna, that is, a double-comb-type antenna, was developed for a large-area plasma source having the size of 1020 mmx830 mm, and high density plasmas on the order of 2.3x10 11 cm -3 were obtained with 15 mTorr Ar at 5000 W of inductive power with good plasma stability. This is higher than that for the conventional serpentine-type antenna, possibly due to the low impedance, resulting in high efficiency of power transfer for the double-comb antenna type. In addition, due to the remarkable reduction of the antenna length, a plasma uniformity of less than 8% was obtained within the substrate area of 880 mmx660 mm at 5000 W without having a standing-wave effect
Radioimmunoasay of calcitonin in plasma and cerebro-spinal fluid
Cecchettin, M.; Comberti, E.; Quinzanini, M.; Albertini, A.; Tarquini, B.
1985-01-01
An acceptable radioimmunoassay of calcitonin (CT) in man requires a highly purified antigen that can be labelled without loss of immunoreactivity. Radiolabelled synthetic CT showed an additional large peak of radiopeptides with high molecular weight. Therefore, a standard electrofocussing experiment was performed. Standards exhibiting an atypical behaviour after radioiodination showed a pI different from synthetic human monomer. CT electrophoretogram shows a larger component at pI 7.9 and two smaller contaminations at pI 8.6. Besides, the antisera available for CT assay are considered in healthy subjects. 0H 2 and COOH assays give non-homogeneous results. A CT assay in cerebrospinal fluid is performed. The direct assay was unable to detect significant correlation between serum and cerebrospinal levels both in physiological and pathological conditions. Finally, the quality control of the CT assay is discussed. (Auth./G.J.P.)
Dubin, D. H. E.
This chapter explores several aspects of the linear electrostatic normal modes of oscillation for a single-species non-neutral plasma in a Penning trap. Linearized fluid equations of motion are developed, assuming the plasma is cold but collisionless, which allow derivation of the cold plasma dielectric tensor and the electrostatic wave equation. Upper hybrid and magnetized plasma waves in an infinite uniform plasma are described. The effect of the plasma surface in a bounded plasma system is considered, and the properties of surface plasma waves are characterized. The normal modes of a cylindrical plasma column are discussed, and finally, modes of spheroidal plasmas, and finite temperature effects on the modes, are briefly described.
Review and limitations of 3D plasma blob modeling with reduced collisional fluid equations
Angus, Justin R., E-mail: jangus@ucsd.edu [University of California, San Diego, La Jolla, CA (United States); Umansky, Maxim V. [Lawrence Livermore National Laboratory, Livermore, CA (United States); Krashenninikov, Sergei I. [University of California, San Diego, La Jolla, CA (United States)
2013-07-15
Recent 3D studies on plasma blobs (coherent structures found in the edge region of magnetic confinement devices) have demonstrated that the drift wave instability can strongly limit the blob’s coherency and cross field convective nature that is predicted by 2D theory. However, the dominant unstable drift wave modes that effect plasma blobs were found to exist in parameter regimes that only marginally satisfied several of the major assumptions considered for the validity of the reduced collisional fluid equations used in the study. Namely, the neglect of electron heat flow, finite electron mean free path effects, and thermal ions. A follow up study demonstrated how the drift wave instability might change if a set of equations that does not suffer from the limitations mentioned above were considered. In the present paper, the results of this later work are used to discuss the limitations on using the collisional fluid equations for 3D studies of plasma blobs.
Richtmyer–Meshkov instability of a thermal interface in a two-fluid plasma
Bond, D.
2017-11-03
We computationally investigate the Richtmyer–Meshkov instability of a density interface with a single-mode perturbation in a two-fluid, ion–electron plasma with no initial magnetic field. Self-generated magnetic fields arise subsequently. We study the case where the density jump across the initial interface is due to a thermal discontinuity, and select plasma parameters for which two-fluid plasma effects are expected to be significant in order to elucidate how they alter the instability. The instability is driven via a Riemann problem generated precursor electron shock that impacts the density interface ahead of the ion shock. The resultant charge separation and motion generates electromagnetic fields that cause the electron shock to degenerate and periodically accelerate the electron and ion interfaces, driving Rayleigh–Taylor instability. This generates small-scale structures and substantially increases interfacial growth over the hydrodynamic case.
van Eck, H.J.N.; Hansen, T.A.R.; Kleyn, A.W.; van der Meiden, H.J.; Schram, D.C.; Zeijlmans van Emmichoven, P.A.
2011-01-01
Magnum-PSI is a linear plasma generator designed to reach the plasma-surface interaction (PSI) regime of ITER and nuclear fusion reactors beyond ITER. To reach this regime, the influx of cold neutrals from the source must be significantly lower than the plasma flux reaching the target. This is
Kaplan, S.A.; Lomadze, R.D.
1978-01-01
A second approximation to the theory of turbulent plasma reactors in connection with the problem of interpretation of the non-linear spectra of cosmic radio sources has been investigated by the authors (Kaplan and Lomadze, 1977; Lomadze, 1977). The present paper discusses the basic results received for a Compton reactor with plasma waves of phase velocities smaller than the velocity of light, as well as for the synchrotron reactor. The distortion of the distribution function of relativistic electrons caused by their diffusion from the reactor is also presented as an example. (Auth.)
Silva, Filipe da; Pinto, Martin Campos; Després, Bruno; Heuraux, Stéphane
2015-01-01
This work analyzes the stability of the Yee scheme for non-stationary Maxwell's equations coupled with a linear current model with density fluctuations. We show that the usual procedure may yield unstable scheme for physical situations that correspond to strongly magnetized plasmas in X-mode (TE) polarization. We propose to use first order clustered discretization of the vectorial product that gives back a stable coupling. We validate the schemes on some test cases representative of direct numerical simulations of X-mode in a magnetic fusion plasma including turbulence
Kalidas Das
2018-03-01
Full Text Available The temperament of stream characteristic, heat and mass transfer of MHD forced convective flow over a linearly expanding porous medium has been scrutinized in the progress exploration. The germane possessions of the liquid like viscosity along with thermal conductivity are believed to be variable in nature, directly influenced by the temperature of flow. As soon as gaining the system of leading equations of the stream, Lie symmetric group transformations have been employed to come across the fitting parallel conversions to alter the central PDEs into a suit of ODEs. The renovated system of ODE with appropriate boundary conditions is numerically solved with the assistance of illustrative software MAPLE 17. The consequences of the relevant factors of the system have been exemplified through charts and graphs. An analogous qualified survey has been prepared among present inquiry and subsisting reads and achieved an admirable accord between them. The variable viscosity parameter has more significant effect on nanofluid velocity than regular fluid and temporal profile as well as nanoparticle concentration is also influenced with variable viscosity. Keywords: Nanofluid, Stretching sheet, Variable viscosity, Variable thermal conductivity, Lie symmetry group
Role of size on the relative importance of fluid dynamic losses in linear cryocoolers
Kirkconnell, Carl; Ghavami, Ali; Ghiaasiaan, S. Mostafa; Perrella, Matthew
2017-12-01
Thermodynamic modeling results for a novel small satellite (SmallSat) Stirling Cryocooler, capable of delivering over 200 mW net cooling power at 80 K for less than 6 W DC input power, are used in this paper as the basis for related pulse tube computational fluid dynamics (CFD) analysis. Industry and government requirements for SmallSat infrared sensors are driving the development of ever-more miniaturized cryocooler systems. Such cryocoolers must be extremely compact and lightweight, a challenge met by this research team through operating a Stirling cryocooler at a frequency of approximately 300 Hz. The primary advantage of operating at such a high frequency is that the required compression and expansion swept volumes are reduced relative to linear coolers operating at lower frequencies, which evidently reduces the size of the motor mechanisms and the thermodynamic components. In the case of a pulse tube cryocooler, this includes a reduction in diameter of the pulse tube itself. This unfortunately leads to high boundary layer losses, as the presented results demonstrate. Using a Stirling approach with a mechanical moving expander piston eliminates this small pulse tube loss mechanism, but other challenges are introduced, such as maintaining very tight clearance gaps between moving and stationary elements. This paper focuses on CFD modelling results for a highly miniaturized pulse tube cooler.
Inviscid linear stability analysis of two fluid columns of different densities subject to gravity
Prathama, Aditya; Pantano, Carlos
2017-11-01
We investigate the inviscid linear stability of vertical interface between two fluid columns of different densities under the influence of gravity. In this flow arrangement, the two free streams are continuously accelerating, in contrast to the canonical Kelvin-Helmholtz or Rayleigh-Taylor instabilities whose base flows are stationary (or weakly time dependent). In these classical cases, the temporal evolution of the interface can be expressed as Fourier or Laplace solutions in time. This is not possible in our case; instead, we employ the initial value problem method to solve the equations analytically. The results, expressed in terms of the well-known parabolic cylinder function, indicate that the instability grows as the exponential of a quadratic function of time. The analysis shows that in this accelerating Kelvin-Helmholtz configuration, the interface is unconditionally unstable at all wave modes, despite the presence of surface tension. Department of Energy, National Nuclear Security Administration (Award No. DE-NA0002382) and the California Institute of Technology.
Seismic energy dissipation study of linear fluid viscous dampers in steel structure design
A. Ras
2016-09-01
Full Text Available Energy dissipation systems in civil engineering structures are sought when it comes to removing unwanted energy such as earthquake and wind. Among these systems, there is combination of structural steel frames with passive energy dissipation provided by Fluid Viscous Dampers (FVD. This device is increasingly used to provide better seismic protection for existing as well as new buildings and bridges. A 3D numerical investigation is done considering the seismic response of a twelve-storey steel building moment frame with diagonal FVD that have linear force versus velocity behaviour. Nonlinear time history, which is being calculated by Fast nonlinear analysis (FNA, of Boumerdes earthquake (Algeria, May 2003 is considered for the analysis and carried out using the SAP2000 software and comparisons between unbraced, braced and damped structure are shown in a tabulated and graphical format. The results of the various systems are studied to compare the structural response with and without this device of the energy dissipation thus obtained. The conclusions showed the formidable potential of the FVD to improve the dissipative capacities of the structure without increasing its rigidity. It is contributing significantly to reduce the quantity of steel necessary for its general stability.
The relative importance of fluid and kinetic frequency shifts of an electron plasma wave
Winjum, B. J.; Fahlen, J.; Mori, W. B.
2007-10-01
The total nonlinear frequency shift of a plasma wave including both fluid and kinetic effects is estimated when the phase velocity of the wave is much less than the speed of light. Using a waterbag or fluid model, the nonlinear frequency shift due to harmonic generation is calculated for an arbitrary shift in the wavenumber. In the limit where the wavenumber does not shift, the result is in agreement with previously published work [R. L. Dewar and J. Lindl, Phys. Fluids 15, 820 (1972); T. P. Coffey, Phys. Fluids 14, 1402 (1971)]. This shift is compared to the kinetic shift of Morales and O'Neil [G. J. Morales and T. M. O'Neil, Phys. Rev. Lett. 28, 417 (1972)] for wave amplitudes and values of kλD of interest to Raman backscatter of a laser driver in inertial confinement fusion.
Fuglsang, Stefan; Henriksen, Ulrik L; Hansen, Hanne Boskov
2017-01-01
In patients with fluid retention, the plasma clearance of (51) Cr-EDTA (Clexp obtained by multiexponential fit) may overestimate the glomerular filtration rate (GFR). The present study was undertaken to compare a gamma-variate plasma clearance (Clgv) with the urinary plasma clearance of (51) Cr......-EDTA (Clu ) in patients with cirrhosis with and without fluid retention. A total of 81 patients with cirrhosis (22 without fluid retention, 59 with ascites) received a quantitative intravenous injection of (51) Cr-EDTA followed by plasma and quantitative urinary samples for 5 h. Clgv was determined from...... the injected dose relative to the plasma concentration-time area, obtained by a gamma-variate iterative fit. Clexp and Clu were determined by standard technique. In patients without fluid retention, Clgv , Clexp and Clu were closely similar. The difference between Clgv and Clu (Clgv - Clu = ΔCl) was mean -0...
Larsen, Jon Steffen; Santos, Ilmar
2015-01-01
An efficient finite element scheme for solving the non-linear Reynolds equation for compressible fluid coupled to compliant structures is presented. The method is general and fast and can be used in the analysis of airfoil bearings with simplified or complex foil structure models. To illustrate...
A blended continuous–discontinuous finite element method for solving the multi-fluid plasma model
Sousa, E.M., E-mail: sousae@uw.edu; Shumlak, U., E-mail: shumlak@uw.edu
2016-12-01
The multi-fluid plasma model represents electrons, multiple ion species, and multiple neutral species as separate fluids that interact through short-range collisions and long-range electromagnetic fields. The model spans a large range of temporal and spatial scales, which renders the model stiff and presents numerical challenges. To address the large range of timescales, a blended continuous and discontinuous Galerkin method is proposed, where the massive ion and neutral species are modeled using an explicit discontinuous Galerkin method while the electrons and electromagnetic fields are modeled using an implicit continuous Galerkin method. This approach is able to capture large-gradient ion and neutral physics like shock formation, while resolving high-frequency electron dynamics in a computationally efficient manner. The details of the Blended Finite Element Method (BFEM) are presented. The numerical method is benchmarked for accuracy and tested using two-fluid one-dimensional soliton problem and electromagnetic shock problem. The results are compared to conventional finite volume and finite element methods, and demonstrate that the BFEM is particularly effective in resolving physics in stiff problems involving realistic physical parameters, including realistic electron mass and speed of light. The benefit is illustrated by computing a three-fluid plasma application that demonstrates species separation in multi-component plasmas.
Fluid and gyrokinetic modelling of particle transport in plasmas with hollow density profiles
Tegnered, D; Oberparleiter, M; Nordman, H; Strand, P
2016-01-01
Hollow density profiles occur in connection with pellet fuelling and L to H transitions. A positive density gradient could potentially stabilize the turbulence or change the relation between convective and diffusive fluxes, thereby reducing the turbulent transport of particles towards the center, making the fuelling scheme inefficient. In the present work, the particle transport driven by ITG/TE mode turbulence in regions of hollow density profiles is studied by fluid as well as gyrokinetic simulations. The fluid model used, an extended version of the Weiland transport model, Extended Drift Wave Model (EDWM), incorporates an arbitrary number of ion species in a multi-fluid description, and an extended wavelength spectrum. The fluid model, which is fast and hence suitable for use in predictive simulations, is compared to gyrokinetic simulations using the code GENE. Typical tokamak parameters are used based on the Cyclone Base Case. Parameter scans in key plasma parameters like plasma β, R/L T , and magnetic shear are investigated. It is found that β in particular has a stabilizing effect in the negative R/L n region, both nonlinear GENE and EDWM show a decrease in inward flux for negative R/L n and a change of direction from inward to outward for positive R/L n . This might have serious consequences for pellet fuelling of high β plasmas. (paper)
Hamiltonian structure of reduced fluid models for plasmas obtained from a kinetic description
Guillebon, L. de; Chandre, C.
2012-01-01
We consider the Hamiltonian structure of reduced fluid models obtained from a kinetic description of collisionless plasmas by Vlasov–Maxwell equations. We investigate the possibility of finding Poisson subalgebras associated with fluid models starting from the Vlasov–Maxwell Poisson algebra. In this way, we show that the only possible Poisson subalgebra involves the moments of zeroth and first order of the Vlasov distribution, meaning the fluid density and the fluid velocity. We find that the bracket derived in [B.A. Shadwick, G.M. Tarkenton, E.H. Esarey, Phys. Rev. Lett. 93 (2004) 175002] which involves moments of order 2 is not a Poisson bracket since it does not satisfy the Jacobi identity. -- Highlights: ► We investigate fluid reductions from the Vlasov–Maxwell Poisson bracket. ► The only Poisson subalgebra involves fluid density and fluid velocity. ► The bracket derived in [B.A. Shadwick, G.M. Tarkenton, E.H. Esarey, Phys. Rev. Lett. 93 (2004) 175002] is not Hamiltonian.
Linear coupling of electromagnetic and Jeans modes in self-gravitating plasma streams
Yaroshenko, Victoria V.; Voitenko, Yuriy; Goossens, Marcel
2002-01-01
A new mechanism of linear coupling between electromagnetic (nonpotential) and gravitational disturbances is found for oblique propagation relatively to particle streams. The general dispersion law is derived and applied to the case of two countersteaming dust beams of equal strength and quiasiperpendicular propagation. It reveals a strong linear coupling between the low-frequency aperiodically unstable electromagnetic (AEM) and the Jeans (JM) modes. The coupling is of a mode conversion type, resulting in a frequency gap in the dispersion, and thus significantly modifies the instability criteria. It is shown that, in contrast to the electrostatic case, AEM and JM coupling in streaming self-gravitating plasmas can actually appear even if the plasma frequencies of the dust species greatly exceed the corresponding Jeans frequencies
A Concept of Plasma Wake Field Acceleration Linear Collider (PWFA-LC)
Seryi, Andrei; Hogan, Mark; Pei, Shilun; Raubenheimer, Tor; Tenenbaum, Peter; Katsouleas, Tom; Huang, Chengkun; Joshi, Chan; Mori, Warren; Muggli, Patric
2009-01-01
Plasma Wake-Field Acceleration (PWFA) has demonstrated acceleration gradients above 50 GeV/m. Simulations have shown drive/witness bunch configurations that yield small energy spreads in the accelerated witness bunch and high energy transfer efficiency from the drive bunch to the witness bunch, ranging from 30% for a Gaussian drive bunch to 95% for a shaped longitudinal profile. These results open the opportunity for a linear collider that could be compact, efficient and more cost effective that the present microwave technologies. A concept of a PWFA-based Linear Collider (PWFA-LC) has been developed and is described in this paper. The drive beam generation and distribution, requirements on the plasma cells, and optimization of the interaction region parameters are described in detail. The R and D steps needed for further development of the concept are also outlined.
Kinetics and hybrid kinetic-fluid models for nonequilibrium gas and plasmas
Crouseilles, N.
2004-12-01
For a few decades, the application of the physics of plasmas has appeared in different fields like laser-matter interaction, astrophysics or thermonuclear fusion. In this thesis, we are interested in the modeling and the numerical study of nonequilibrium gas and plasmas. To describe such systems, two ways are usually used: the fluid description and the kinetic description. When we study a nonequilibrium system, fluid models are not sufficient and a kinetic description have to be used. However, solving a kinetic model requires the discretization of a large number of variables, which is quite expensive from a numerical point of view. The aim of this work is to propose a hybrid kinetic-fluid model thanks to a domain decomposition method in the velocity space. The derivation of the hybrid model is done in two different contexts: the rarefied gas context and the more complicated plasmas context. The derivation partly relies on Levermore's entropy minimization approach. The so-obtained model is then discretized and validated on various numerical test cases. In a second stage, a numerical study of a fully kinetic model is presented. A collisional plasma constituted of electrons and ions is considered through the Vlasov-Poisson-Fokker-Planck-Landau equation. Then, a numerical scheme which preserves total mass and total energy is presented. This discretization permits in particular a numerical study of the Landau damping. (author)
Novel features of non-linear Raman instability in a laser plasma
Mašek, Martin; Rohlena, Karel
2010-01-01
Roč. 56, č. 1 (2010), s. 79-90 ISSN 1434-6060 R&D Projects: GA MŠk(CZ) 7E08099; GA MŠk(CZ) LC528; GA ČR GA202/05/2475 Institutional research plan: CEZ:AV0Z10100523 Keywords : laser plasma * non-linear Raman instability Subject RIV: BH - Optics, Masers, Lasers Impact factor: 1.513, year: 2010
Plasma Cell Cerebrospinal Fluid Pleocytosis Does Not Predict West Nile Virus Infection
Michael Jordan
2012-01-01
Full Text Available Purpose. Diagnosis of WNV (WNV relies upon serologic testing which may take several days after the onset of clinical symptoms to turn positive. Anecdotal reports suggest the presence of plasma cells or plasmacytoid lymphocytes in the cerebrospinal fluid (CSF may be an early indicator of WNV infection. Methods. The CSFs of 89 patients (12 with WNV, 12 with other viral illness {OVI}, and 65 with nonviral illness{NVI} were compared for the presence of either plasma cells or plasmacytoid lymphocytes. Results. Plasma cells were rarely seen in any of the patients. Plasmacytoid lymphocytes were more commonly seen in WNV (58% and OVI (50% than NVI (11%. The differences were significant for WNV versus NVI, but not WNV versus OVI (P<0.001 and P=0.58, resp.. Conclusions. A CSF pleocytosis with plasma cells or plasmacytoid lymphocytes was neither sensitive nor specific for the diagnosis of WNV infection.
Adaptive grids and numerical fluid simulations for scrape-off layer plasmas
Klingshirn, Hans-Joachim
2010-01-01
Magnetic confinement nuclear fusion experiments create plasmas with local temperatures in excess of 100 million Kelvin. In these experiments the scrape-off layer, which is the plasma region in direct contact with the device wall, is of central importance both for the quality of the energy confinement and the wall material lifetime. To study the behaviour of the scrape-off layer, in addition to experiments, numerical simulations are used. This work investigates the use of adaptive discretizations of space and compatible numerical methods for scrape-off layer simulations. The resulting algorithms allow dynamic adaptation of computational grids aligned to the magnetic fields to precisely capture the strongly anisotropic energy and particle transport in the plasma. The methods are applied to the multi-fluid plasma code B2, with the goal of reducing the runtime of simulations and extending the applicability of the code.
Kinetics of HIV-1 in cerebrospinal fluid and plasma in cryptococcal meningitis
Jorge A. Benetucci
2012-04-01
Full Text Available In order to determine HIV-1 kinetics in cerebrospinal fluid (CSF and plasma in patients with cryptococcal meningitis (CM, we undertook a prospective collection of paired CSF/plasma samples from antiretroviral therapy- free HIV-infected patients with CM. Samples were obtained at baseline (S1 and at the second (S2 and third (S3 weeks of antifungal therapy. HIV-1 CSF concentrations were significantly lower in both S2 and S3 with respect to S1. Plasma concentrations remained stable. HIV-1 concentrations were higher in plasma than CSF in all cases. Patients who survived the episode of CM (but not those who died showed a decrease in CSF viral load, what suggests different viral kinetics of HIV-1 in the CSF according to the clinical course of this opportunistic disease.
Zonal flows and turbulence in fluids and plasmas
Parker, Jeffrey Bok-Cheung
In geophysical and plasma contexts, zonal flows are well known to arise out of turbulence. We elucidate the transition from statistically homogeneous turbulence without zonal flows to statistically inhomogeneous turbulence with steady zonal flows. Starting from the Hasegawa--Mima equation, we employ both the quasilinear approximation and a statistical average, which retains a great deal of the qualitative behavior of the full system. Within the resulting framework known as CE2, we extend recent understanding of the symmetry-breaking 'zonostrophic instability'. Zonostrophic instability can be understood in a very general way as the instability of some turbulent background spectrum to a zonally symmetric coherent mode. As a special case, the background spectrum can consist of only a single mode. We find that in this case the dispersion relation of zonostrophic instability from the CE2 formalism reduces exactly to that of the 4-mode truncation of generalized modulational instability. We then show that zonal flows constitute pattern formation amid a turbulent bath. Zonostrophic instability is an example of a Type I s instability of pattern-forming systems. The broken symmetry is statistical homogeneity. Near the bifurcation point, the slow dynamics of CE2 are governed by a well-known amplitude equation, the real Ginzburg-Landau equation. The important features of this amplitude equation, and therefore of the CE2 system, are multiple. First, the zonal flow wavelength is not unique. In an idealized, infinite system, there is a continuous band of zonal flow wavelengths that allow a nonlinear equilibrium. Second, of these wavelengths, only those within a smaller subband are stable. Unstable wavelengths must evolve to reach a stable wavelength; this process manifests as merging jets. These behaviors are shown numerically to hold in the CE2 system, and we calculate a stability diagram. The stability diagram is in agreement with direct numerical simulations of the quasilinear
Opioid Concentrations in Oral Fluid and Plasma in Cancer Patients With Pain.
Heiskanen, Tarja; Langel, Kaarina; Gunnar, Teemu; Lillsunde, Pirjo; Kalso, Eija A
2015-10-01
Measuring opioid concentrations in pain treatment is warranted in situations where optimal opioid analgesia is difficult to reach. To assess the usefulness of oral fluid (OFL) as an alternative to plasma in opioid concentration monitoring in cancer patients on chronic opioid therapy. We collected OFL and plasma samples from 64 cancer patients on controlled-release (CR) oral morphine, CR oral oxycodone, or transdermal (TD) fentanyl for pain. Samples were obtained on up to five separate days. A total of 213 OFL and plasma samples were evaluable. All patients had detectable amounts of the CR or TD opioid in both plasma and OFL samples. The plasma concentrations of oxycodone and fentanyl (determination coefficient R(2) = 0.628 and 0.700, respectively), but not morphine (R(2) = 0.292), were moderately well correlated to the daily opioid doses. In contrast to morphine and fentanyl (mean OFL/plasma ratio 2.0 and 3.0, respectively), the OFL oxycodone concentrations were significantly higher than the respective plasma concentrations (mean OFL/plasma ratio 14.9). An active transporter could explain the much higher OFL vs. plasma concentrations of oxycodone compared with morphine and fentanyl. OFL analysis is well suited for detecting the studied opioids. For morphine and fentanyl, an approximation of the plasma opioid concentrations is obtainable, whereas for oxycodone, the OFL/plasma concentration relationship is too variable for reliable approximation results. Copyright © 2015 American Academy of Hospice and Palliative Medicine. Published by Elsevier Inc. All rights reserved.
Effect of Rehydration Fluid Osmolality on Plasma Volume and Vasopressin in Resting Dehydrated Men
Geelen, Ghislaine; Greenleaf, J. E.; Keil, L. C.; Wade, Charles E. (Technical Monitor)
1994-01-01
Elevated plasma vasopressin concentration [PVP], which may act as a dipsogen, decreases promptly following the ingestion of fluids in many mammals including humans. The purpose for this study was to determine whether fluids of varied electrolyte and carbohydrate composition and osmolality (Osm] would modify post-drinking decreases in [PVP] which could be attributed to interaction with plasma volume (PV)- or fluid-electrolyte interactive hormones. Five men (23-41 yr, 78.0 +/- SD 8.2 kg), water deprived for 24 h, drank six fluids (12 ml/kg, at 16.5C in 4.0-6.2 min): water (30 m0sm/kg), NaCl (70 mOsm/kg), NaCl + NaCitrate (270 mOsm/kg), NaCl + 9.7% glucose (650 mOsm/kg), and two commercial drinks containing various ionic and carbohydrate contents (380 and 390 mOsm/kg). Blood (20 ml/sample) was drawn at -5 min before and at +3, +9, +15, +30, and +70 min after drinking. Heart rate, blood pressures, and plasma renin activity, {Na+], [K+], [Osm], aldosterone, atrial natriuretic peptide, and epinephrine concentrations were unchanged after drinking. Post-drinking [PVP] decreased from 1.7 - 3.7 pg/ml within 3 min with all fluids independently of their composition, [Osm], or delta PV; with maximal depression to 0.1-0.7 pg/ml (p<0.05) by 15 min. The continued [PVP] depression with all fluids from 15 to 70 min was accompanied by unchanged plasma (Osm] but 1.8-7.6% increases (p<0.05) in PV with 3) fluids (2 commercial and NaCitrate) and no change with the others. Percent changes in mean [PVP] and plasma norepinephrine concentrations [PNE] at 15 min correlated -0.70 (P<0.10) suggesting that about half the variability in [PVP I I depression was associated with [PNE]. Thus, part of the mechanism for post-drinking [PVP] depression may involve a drinking stimulated norepinephrine (neural) factor.
Linear and nonlinear dynamics of current-driven waves in dusty plasmas
Ahmad, Ali; Ali Shan, S.; Haque, Q.; Saleem, H.
2012-09-01
The linear and nonlinear dynamics of a recently proposed plasma mode of dusty plasma is studied using kappa distribution for electrons. This electrostatic wave can propagate in the plasma due to the sheared flow of electrons and ions parallel to the external magnetic field in the presence of stationary dust. The coupling of this wave with the usual drift wave and ion acoustic wave is investigated. D'Angelo's mode is also modified in the presence of superthermal electrons. In the nonlinear regime, the wave can give rise to dipolar vortex structures if the shear in flow is weaker and tripolar vortices if the flow has steeper gradient. The results have been applied to Saturn's magnetosphere corresponding to negatively charged dust grains. But the theoretical model is applicable for positively charged dust as well. This work will be useful for future observations and studies of dusty environments of planets and comets.
Linear and nonlinear dynamics of current-driven waves in dusty plasmas
Ahmad, Ali [National Centre for Physics (NCP), Shahdara Valley Road, 44000 Islamabad (Pakistan); Department of Physics, COMSATS Institute of Information Technology (CIIT), Islamabad (Pakistan); Theoretical Plasma Physics Division, PINSTECH, P. O. Nilore, Islamabad (Pakistan); Ali Shan, S.; Haque, Q. [National Centre for Physics (NCP), Shahdara Valley Road, 44000 Islamabad (Pakistan); Theoretical Plasma Physics Division, PINSTECH, P. O. Nilore, Islamabad (Pakistan); Saleem, H. [National Centre for Physics (NCP), Shahdara Valley Road, 44000 Islamabad (Pakistan); Department of Physics, COMSATS Institute of Information Technology (CIIT), Islamabad (Pakistan)
2012-09-15
The linear and nonlinear dynamics of a recently proposed plasma mode of dusty plasma is studied using kappa distribution for electrons. This electrostatic wave can propagate in the plasma due to the sheared flow of electrons and ions parallel to the external magnetic field in the presence of stationary dust. The coupling of this wave with the usual drift wave and ion acoustic wave is investigated. D'Angelo's mode is also modified in the presence of superthermal electrons. In the nonlinear regime, the wave can give rise to dipolar vortex structures if the shear in flow is weaker and tripolar vortices if the flow has steeper gradient. The results have been applied to Saturn's magnetosphere corresponding to negatively charged dust grains. But the theoretical model is applicable for positively charged dust as well. This work will be useful for future observations and studies of dusty environments of planets and comets.
The Use of Multi-Reactor Cascade Plasma Electrolysis for Linear Alkylbenzene Sulfonate Degradation
Saksono, Nelson; Ibrahim; Zainah; Budikania, Trisutanti
2018-03-01
Plasma electrolysis is a method that can produce large amounts of hydroxyl radicals to degrade organic waste. The purpose of this study is to improve the effectiveness of Linear alkylbenzene sulfonate (LAS) degradation by using multi-reactor cascade plasma electrolysis. The reactor which operated in circulation system, using 3 reactors series flow and 6 L of LAS with initial concentration of 100 ppm. The results show that the LAS degradation can be improved multi-reactor cascade plasma electrolysis. The greatest LAS degradation is achieved up to 81.91% with energy consumption of 2227.34 kJ/mmol that is obtained during 120 minutes by using 600 Volt, 0.03 M of KOH, and 0.5 cm of the anode depth.
Swanson, DG
1989-01-01
Plasma Waves discusses the basic development and equations for the many aspects of plasma waves. The book is organized into two major parts, examining both linear and nonlinear plasma waves in the eight chapters it encompasses. After briefly discussing the properties and applications of plasma wave, the book goes on examining the wave types in a cold, magnetized plasma and the general forms of the dispersion relation that characterize the waves and label the various types of solutions. Chapters 3 and 4 analyze the acoustic phenomena through the fluid model of plasma and the kinetic effects. Th
Cottier, Pierre
2013-01-01
The magnetic confinement in tokamaks is for now the most advanced way towards energy production by nuclear fusion. Both theoretical and experimental studies showed that rotation generation can increase its performance by reducing the turbulent transport in tokamak plasmas. The rotation influence on the heat and particle fluxes is studied along with the angular momentum transport with the quasi-linear gyro-kinetic eigenvalue code QuaLiKiz. For this purpose, the QuaLiKiz code is modified in order to take the plasma rotation into account and compute the angular momentum flux. It is shown that QuaLiKiz framework is able to correctly predict the angular momentum flux including the E*B shear induced residual stress as well as the influence of rotation on the heat and particle fluxes. The major approximations of QuaLiKiz formalisms are reviewed, in particular the ballooning representation at its lowest order and the eigenfunctions calculated in the hydrodynamic limit. The construction of the quasi-linear fluxes is also reviewed in details and the quasi-linear angular momentum flux is derived. The different contributions to the turbulent momentum flux are studied and successfully compared both against non-linear gyro-kinetic simulations and experimental data. (author) [fr
Zhang Yuru; Xu Xiang; Wang Younian; Bogaerts, Annemie
2012-01-01
A two-dimensional fluid model, including the full set of Maxwell equations, has been developed and applied to investigate the effect of a phase shift between two power sources on the radial uniformity of several plasma characteristics in a hydrogen capacitively coupled plasma. This study was carried out at various frequencies in the range 13.56-200 MHz. When the frequency is low, at 13.56 MHz, the plasma density is characterized by an off-axis peak when both power sources are in-phase (φ = 0), and the best radial uniformity is obtained at φ = π. This trend can be explained because the radial nonuniformity caused by the electrostatic edge effect can be effectively suppressed by the phase-shift effect at a phase difference equal to π. When the frequency rises to 60 MHz, the plasma density profiles shift smoothly from edge-peaked over uniform to centre-peaked as the phase difference increases, due to the pronounced standing-wave effect, and the best radial uniformity is reached at φ = 0.3π. At a frequency of 100 MHz, a similar behaviour is observed, except that the maximum of the plasma density moves again towards the radial edge at the reverse-phase case (φ = π), because of the dominant skin effect. When the frequency is 200 MHz, the bulk plasma density increases significantly with increasing phase-shift values, and a better uniformity is obtained at φ = 0.4π. This is because the density in the centre increases faster than at the radial edge as the phase difference rises, due to the increasing power deposition P z in the centre and the decreasing power density P r at the radial edge. As the phase difference increases to π, the maximum near the radial edge becomes obvious again. This is because the skin effect has a predominant influence on the plasma density under this condition, resulting in a high density at the radial edge. Moreover, the axial ion flux increases monotonically with phase difference, and exhibits similar profiles to the plasma density
Experimental observation of fluid echoes in a non-neutral plasma
Yu, Jonathan H.; Driscoll, C. Fred
2002-01-01
Experimental observation of a nonlinear fluid echo is presented which demonstrates the reversible nature of spatial Landau damping, and that non-neutral plasmas behave as nearly ideal 2D fluids. These experiments are performed on UCSD's CamV Penning-Malmberg trap with magnetized electron plasmas. An initial m i =2 diocotron wave is excited, and the received wall signal damps away in about 5 wave periods. The density perturbation filaments are observed to wrap up as the wave is spatially Landau damped. An m t =4 'tickler' wave is then excited, and this wave also Landau damps. The echo consists of a spontaneous appearance of a third m e =2 wave after the responses to the first two waves have inviscidly damped away. The appearance time of the echo agrees with theory, and data suggests the echo is destroyed at least partly due to saturation
ERO modeling of Cr sputtering in the linear plasma device PSI-2
Eksaeva, A.; Borodin, D.; Kreter, A.; Nishijima, D.; Pospieszczyk, A.; Schlummer, T.; Ertmer, S.; Terra, A.; Unterberg, B.; Kirschner, A.; Romazanov, J.; Brezinsek, S.; Rasinski, M.; Henderson, S.; O'Mullane, M.; Summers, H.; Bluteau, M.; Marenkov, E.
2017-12-01
The prediction of the first wall deterioration and possible plasma contamination by impurities is a high priority task for ITER. 3D Monte-Carlo code ERO is a tool for modeling of eroded impurity transport and spectroscopy in plasma devices useful for experiment interpretation. Chromium (Cr) is a fusion-relevant reactor wall element (e.g. component of RAFM steels expected for use in DEMO). Linear plasma devices including PSI-2 are effective tools for investigations of plasma-surface interaction effects, allowing continuous plasma operation and good control over irradiation parameters. Experiments on Cr sputtering were conducted at PSI-2. In these experiments the Cr erosion was measured by three techniques: mass loss of the sample, quartz micro-balance of deposited impurities at a distance from it and optical emission spectroscopy. Experiments were modeled with the 3D Monte-Carlo code ERO, previously validated by application to similar experiments with tungsten (W). The simulations are demonstrated to reproduce the main experimental outcomes proving the quality of the sputtering data used. A significant focuses of the paper is the usage and validation of atomic data (resent metastable-resolved dataset from ADAS) for interpretation of Cr spectroscopy. Initial population of quasi-metastable state was fitted by matching the modeling with the experimental line intensity profiles.
Strandby, Rune Broni; Ambrus, Rikard; Secher, Niels H
2017-01-01
BACKGROUND: It remains debated how much fluid should be administered during surgery. The atrial natriuretic peptide precursor proANP is released by atrial distension and deviations in plasma proANP are reported associated with perioperative fluid balance. We hypothesized that plasma proANP would...... decrease when the central blood volume is compromised during the abdominal part of robot-assisted hybrid (RE) esophagectomy and that a positive fluid balance would be required to maintain plasma proANP. METHODS: Patients undergoing RE (n = 25) or open (OE; n = 25) esophagectomy for gastroesophageal cancer...
FINAL REPORT "Extreme non-linear optics of plasmas" Pierre Michel (16-LW-022)
Michel, Pierre [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
2017-11-03
Large laser facilities such as the National Ignition Facility (NIF) are typically limited in performance and physical scale (and thus cost) by optics damage. In this LDRD, we investigated a radically new way to manipulate light at extreme powers and energies, where “traditional” (crystal-based) optical elements are replaced by a medium that is already “broken” and thus does not suffer from optics damage: a plasma. Our method consisted in applying multiple lasers into plasmas to imprint refractive micro-structures with optical properties designed to be similar to those of crystals or dielectric structures used in optics. In particular, we focused our efforts on two elements used to manipulate the polarization of lasers (i.e. the orientation of the light’s electric field vector): i) a polarizer, which only lets a given polarization direction pass and blocks the others, and ii) a “Pockels cell”, which can “rotate” the polarization direction or convert it from linear to elliptical or circular. These two elements are essential building blocks in almost all laser systems – for example, they can be combined to design optical gates. Here, we introduced the new concepts of a “plasma polarizer” and a “plasma Pockels cell”. Both concepts were demonstrated in proof-of-principle laboratory experiments in this LDRD. We also demonstrated that such laser-plasma systems could be used to provide full control of the refractive index of plasmas as well as their dispersion (variation of the index vs. the light wavelength), which constituted the basis for a final experiment aimed at demonstrating the feasibility of “slow light” in plasmas, i.e. the capability to slow down a light pulse almost to a full stop.
Morrison, P.J., E-mail: morrison@physics.utexas.edu [Department of Physics and Institute for Fusion Studies, University of Texas, Austin (United States); Vanneste, J. [School of Mathematics and Maxwell Institute for Mathematical Sciences, University of Edinburgh (United Kingdom)
2016-05-15
A method, called beatification, is presented for rapidly extracting weakly nonlinear Hamiltonian systems that describe the dynamics near equilibria of systems possessing Hamiltonian form in terms of noncanonical Poisson brackets. The procedure applies to systems like fluids and plasmas in terms of Eulerian variables that have such noncanonical Poisson brackets, i.e., brackets with nonstandard and possibly degenerate form. A collection of examples of both finite and infinite dimensions is presented.
Amelia eGreig
2015-01-01
Full Text Available Computational fluid dynamics (CFD simulations of a radio-frequency (13.56 MHz electro-thermal capacitively coupled plasma (CCP micro-thruster have been performed using the commercial CFD-ACE+ package. Standard operating conditions of a 10 W, 1.5 Torr argon discharge were used to compare with previously obtained experimental results for validation. Results show that the driving force behind plasma production within the thruster is ion-induced secondary electrons ejected from the surface of the discharge tube, accelerated through the sheath to electron temperatures up to 33.5 eV. The secondary electron coefficient was varied to determine the effect on the discharge, with results showing that full breakdown of the discharge did not occur for coefficients coefficients less than or equal to 0.01.
Maternal Plasma and Amniotic Fluid Chemokines Screening in Fetal Down Syndrome
Piotr Laudanski
2014-01-01
Full Text Available Objective. Chemokines exert different inflammatory responses which can potentially be related to certain fetal chromosomal abnormalities. The aim of the study was to determine the concentration of selected chemokines in plasma and amniotic fluid of women with fetal Down syndrome. Method. Out of 171 amniocentesis, we had 7 patients with confirmed fetal Down syndrome (15th–18th weeks of gestation. For the purpose of our control, we chose 14 women without confirmed chromosomal aberration. To assess the concentration of chemokines in the blood plasma and amniotic fluid, we used a protein macroarray, which allows the simultaneous determination of 40 chemokines per sample. Results. We showed significant decrease in the concentration of 4 chemokines, HCC-4, IL-28A, IL-31, and MCP-2, and increase in the concentration of CXCL7 (NAP-2 in plasma of women with fetal Down syndrome. Furthermore, we showed decrease in concentration of 3 chemokines, ITAC, MCP-3, MIF, and increase in concentration of 4 chemokines, IP-10, MPIF-1, CXCL7, and 6Ckine, in amniotic fluid of women with fetal Down syndrome. Conclusion. On the basis of our findings, our hypothesis is that the chemokines may play role in the pathogenesis of Down syndrome. Defining their potential as biochemical markers of Down syndrome requires further investigation on larger group of patients.
Lu, LingFeng
2016-01-01
Ion Cyclotron Resonant Heating (ICRH) by waves in 30-80 MHz range is currently used in magnetic fusion plasmas. Excited by phased arrays of current straps at the plasma periphery, these waves exist under two polarizations. The Fast Wave tunnels through the tenuous plasma edge and propagates to its center where it is absorbed. The parasitically emitted Slow Wave only exists close to the launchers. How much power can be coupled to the center with 1 A current on the straps? How do the emitted radiofrequency (RF) near and far fields interact parasitically with the edge plasma via RF sheath rectification at plasma-wall interfaces? To address these two issues simultaneously, in realistic geometry over the size of ICRH antennas, this thesis upgraded and tested the Self-consistent Sheaths and Waves for ICH (SSWICH) code. SSWICH couples self-consistently RF wave propagation and Direct Current (DC) plasma biasing via non-linear RF and DC sheath boundary conditions (SBCs) at plasma/wall interfaces. Its upgrade is full wave and was implemented in two dimensions (toroidal/radial). New SBCs coupling the two polarizations were derived and implemented along shaped walls tilted with respect to the confinement magnetic field. Using this new tool in the absence of SBCs, we studied the impact of a density decaying continuously inside the antenna box and across the Lower Hybrid (LH) resonance. Up to the memory limits of our workstation, the RF fields below the LH resonance changed with the grid size. However the coupled power spectrum hardly evolved and was only weakly affected by the density inside the box. In presence of SBCs, SSWICH-FW simulations have identified the role of the fast wave on RF sheath excitation and reproduced some key experimental observations. SSWICH-FW was finally adapted to conduct the first electromagnetic and RF-sheath 2D simulations of the cylindrical magnetized plasma device ALINE. (author) [fr
The relative importance of fluid and kinetic frequency shifts of an electron plasma wave
Winjum, B. J.; Fahlen, J.; Mori, W. B.
2007-01-01
The total nonlinear frequency shift of a plasma wave including both fluid and kinetic effects is estimated when the phase velocity of the wave is much less than the speed of light. Using a waterbag or fluid model, the nonlinear frequency shift due to harmonic generation is calculated for an arbitrary shift in the wavenumber. In the limit where the wavenumber does not shift, the result is in agreement with previously published work [R. L. Dewar and J. Lindl, Phys. Fluids 15, 820 (1972); T. P. Coffey, ibid. 14, 1402 (1971)]. This shift is compared to the kinetic shift of Morales and O'Neil [G. J. Morales and T. M. O'Neil, Phys. Rev. Lett. 28, 417 (1972)] for wave amplitudes and values of kλ D of interest to Raman backscatter of a laser driver in inertial confinement fusion
Andersen, Michael; Abel, Sarah Maria Niebe; Erleben, Kenny
2017-01-01
We address the task of computing solutions for a separating fluid-solid wall boundary condition model. We present an embarrassingly parallel, easy to implement, fluid LCP solver.We are able to use greater domain sizes than previous works have shown, due to our new solver. The solver exploits matr...
Irradiation of intense characteristic x-rays from weakly ionized linear molybdenum plasma
Sato, Eiichi; Hayasi, Yasuomi
2003-01-01
In the plasma flash x-ray generator, a high-voltage main condenser of approximately 200 nF is charged up to 55 kV by a power supply, and electric charges in the condenser are discharged to an x-ray tube after triggering the cathode electrode. The flash x-rays are then produced. The x-ray tube is a demountable triode that is connected to a turbo molecular pump with a pressure of approximately 1 mPa. As electron flows from the cathode electrode are roughly converged to a rod molybdenum target of 2.0 mm in diameter by the electric field in the x-ray tube, weakly ionized linear plasma, which consists of molybdenum ions and electrons, forms by target evaporation. At a charging voltage of 55 kV, the maximum tube voltage was almost equal to the charging voltage of the main condenser, and the peak current was about 20 kA. When the charging voltage was increased, the linear plasma formed, and the K-series characteristic x-ray intensities increased. The K lines were quite sharp and intense, and hardly any bremsstrahlung rays were detected. The x-ray pulse widths were approximately 700 ns, and the time-integrated x-ray intensity had a value of approximately 35 μC/kg at 1.0 m from the x-ray source with a charging voltage of 50 kV. (author)
Progranulin Levels in Plasma and Cerebrospinal Fluid in Granulin Mutation Carriers
Lieke H.H. Meeter
2016-07-01
Full Text Available Background: Pathogenic mutations in the granulin gene (GRN are causative in 5-10% of patients with frontotemporal dementia (FTD, mostly leading to reduced progranulin protein (PGRN levels. Upcoming therapeutic trials focus on enhancing PGRN levels. Methods: Fluctuations in plasma PGRN (n = 41 and its relationship with cerebrospinal fluid (CSF, n = 32 and specific single nucleotide polymorphisms were investigated in pre- and symptomatic GRN mutation carriers and controls. Results: Plasma PGRN levels were lower in carriers than in controls and showed a mean coefficient of variation of 5.3% in carriers over 1 week. Although plasma PGRN correlated with CSF PGRN in carriers (r = 0.54, p = 0.02, plasma only explained 29% of the variability in CSF PGRN. rs5848, rs646776 and rs1990622 genotypes only partly explained the variability of PGRN levels between subjects. Conclusions: Plasma PGRN is relatively stable over 1 week and therefore seems suitable for treatment monitoring of PGRN-enhancing agents. Since plasma PGRN only moderately correlated with CSF PGRN, CSF sampling will additionally be needed in therapeutic trials.
Scale-lengths and instabilities in magnetized classical and relativistic plasma fluid models
Diver, D A; Laing, E W
2015-01-01
The validity of the traditional plasma continuum is predicated on a hierarchy of scale-lengths, with the Debye length being considered to be effectively unresolvable in the continuum limit. In this article, we revisit the strong magnetic field case in which the Larmor radius is comparable or smaller than the Debye length in the classical plasma, and also for a relativistic plasma. Fresh insight into the validity of the continuum assumption in each case is offered, including a fluid limit on the Alfvén speed that may impose restrictions on the validity of magnetohydrodynamics (MHD) in some solar and fusion contexts. Additional implications concerning the role of the firehose instability are also explored. (paper)
Gyro-viscosity and linear dispersion relations in pair-ion magnetized plasmas
Kono, M. [Faculty of Policy Studies, Chuo University, Tokyo 192-0393 (Japan); Vranjes, J. [Instituto de Astrofisica de Canarias, Tenerife E38205 (Spain); Departamento de Astrofisica, Universidad de La Laguna, Tenerife E38205 (Spain)
2015-11-15
A fluid theory has been developed by taking account of gyro-viscosity to study wave propagation characteristics in a homogeneous pair-ion magnetized plasma with a cylindrical symmetry. The exact dispersion relations derived by the Hankel-Fourier transformation are shown comparable with those observed in the experiment by Oohara and co-workers. The gyro-viscosity is responsible for the change in propagation characteristics of the ion cyclotron wave from forward to backward by suppressing the effect of the thermal pressure which normally causes the forward nature of dispersion. Although the experiment has been already explained by a kinetic theory by the present authors, the kinetic derivations are so involved because of exact particle orbits in phase space, finite Lamor radius effects, and higher order ion cyclotron resonances. The present fluid theory provides a simple and transparent structure to the dispersion relations since the gyro-viscosity is renormalized into the ion cyclotron frequency which itself indicates the backward nature of dispersion. The usual disadvantage of a fluid theory, which treats only fundamental modes of eigen-waves excited in a system and is not able to describe higher harmonics that a kinetic theory does, is compensated by simple derivations and clear picture based on the renormalization of the gyro-viscosity.
Qin, Hong; Davidson, Ronald C.
2011-01-01
In a linear trap confining a one-component nonneutral plasma, the external focusing force is a linear function of the configuration coordinates and/or the velocity coordinates. Linear traps include the classical Paul trap and the Penning trap, as well as the newly proposed rotating-radio- frequency traps and the Mobius accelerator. This paper describes a class of self-similar nonlinear solutions of nonneutral plasma in general time-dependent linear focusing devices, with self-consistent electrostatic field. This class of nonlinear solutions includes many known solutions as special cases.
Incompressible LFR MHD. A fluid model for stability analysis of a fusion plasma
Scheffel, J.; Faghihi, M.
1986-10-01
A fluid model including FLR effects, named Incompressible Finite Larmor Radius MagnetoHydroDynamics, is presented and derived in this paper. It is an extension of ordinary, incompressible MHD to include the Larmor radius effects due to ion gyroviscosity, Hall current and electron diamagnetism. It is intended to use the model for stability analysis, on the Alfven wave time scale, of a fusion plasma and it is consequently based on transport coefficients in the collisionless limit. It will be demonstrated that for a fairly dense and cool plasma, such as for the EXTRAP z-pinch, all three Larmor radius effects may become important, that for a JET-type plasma no FLR effect is pronounced, and that in a reactor plasma the Hall and electron diamagnetism term may play a role. For scaling lengths signigicantly smaller than the plasma radius the effect of the FLR terms becomes enhanced. To study the importance of the choice of equations of state for the model the m=1 and k 2 r 2 towards infinity instability in cylindrical geometry is given special attention for zero Larmor radius. The full stability criterion of the double adiabatic model, including pressure anisotropy, is presented for what we believe to be the first time. It is found that when perpendicular p > parallel p stability can be reached for very high plasma perpendicular β-values. We demonstrate that no less complicated energy conserving fluid model, which takes into account pressure anisotropy, other than the double adiabativ model can be obtained. Since pressure anisotropy generally only weakly affects stability, we can assume isotropy in the Incompressible FLR MHD model. Also, the energy equation is replaced by the incompressibility condition, making FLR terms appearing in the energy equation irrelevant. (authors)
Zubarev, N.M.; Zubareva, O.V.
2017-01-01
The magnetic shaping problem is studied for the situation where a cylindrical column of a perfectly conducting fluid is deformed by the magnetic field of a system of linear current-carrying conductors. Equilibrium is achieved due to the balance of capillary and magnetic pressures. Two two-parametric families of exact solutions of the problem are obtained with the help of conformal mapping technique. In accordance with them, the column essentially deforms in the cross section up to its disintegration.
Zubarev, N. M.; Zubareva, O. V.
2017-06-01
The magnetic shaping problem is studied for the situation where a cylindrical column of a perfectly conducting fluid is deformed by the magnetic field of a system of linear current-carrying conductors. Equilibrium is achieved due to the balance of capillary and magnetic pressures. Two two-parametric families of exact solutions of the problem are obtained with the help of conformal mapping technique. In accordance with them, the column essentially deforms in the cross section up to its disintegration.
Melissa A McAlexander
2013-05-01
Full Text Available Interest in extracellular RNA has intensified as evidence accumulates that these molecules may be useful as indicators of a wide variety of biological conditions. To establish specific extracellular RNA molecules as clinically relevant biomarkers, reproducible recovery from biological samples and reliable measurements of the isolated RNA are paramount. Towards these ends, careful and rigorous comparisons of technical procedures are needed at all steps from sample handling to RNA isolation to RNA measurement protocols. In the investigations described in this methods paper, RT-qPCR was used to examine the apparent recovery of specific endogenous miRNAs and a spiked-in synthetic RNA from blood plasma samples. RNA was isolated using several widely used RNA isolation kits, with or without the addition of glycogen as a carrier. Kits examined included total RNA isolation systems that have been commercially available for several years and commonly adapted for extraction of biofluid RNA, as well as more recently introduced biofluids-specific RNA methods. Our conclusions include the following: some RNA isolation methods appear to be superior to others for the recovery of RNA from biological fluids; addition of a carrier molecule seems to be beneficial for some but not all isolation methods; and partially or fully quantitative recovery of RNA is observed from increasing volumes of plasma and cerebrospinal fluid.
Henriksen, Ulrik Lütken; Hansen, Hanne B; Ring-Larsen, Helmer
2015-01-01
the injected dose relative to the plasma concentration-time area, extrapolated to infinity. ClU was determined as urinary excretion relative to the plasma concentration-time area up to voiding. Results. In patients without fluid retention, the difference between ClP and ClU (ClP - ClU = ClΔ) was mean 4.5 m...
Experimental investigation of linear mode conversion in laser-produced plasmas
Maaswinkel, A.G.M.
1980-12-01
In this work absorption mechanisms are investigated in hot dense plasmas produced by intense laser irradiation of planar targets. Central in this investigation stands the absorption by linear mode conversion; this process occurs in inhomogeneous plasmas if the electric field vector of the incident EM-wave has a component parallel to the density gradient; this causes electrostatic oscillations at the critical density (where ωsub(p)sub(e) = ω). In addition, absorption of the laser light by inverse bremsstrahlung is investigated. The absorption is determined by the reflection of the laser light from the plasma. To this aim optical diagnostics are used. The reflection into 4π sr is measured with an Ulbricht sphere, also the reflection in specular (geometric) direction is recorded. The absorption mechanisms have been isolated by variation of the polarization of the beam and the angle of incidence to the target. An essential part of the work has been the frequency up-conversion of the laser beam by nonlinear crystals; in this way the wavelength-dependence of the absorption in the plasma has been investigated at wavelengths 1.06 μm, 0.53 μm and 0.26 μm; the pulse duration in the experiments was 30 ps, the maximum irradiation on target was 10 14 W/cm 2 . (orig./HT)
Linear and Nonlinear Response of a Rotating Tokamak Plasma to a Resonant Error-Field
Fitzpatrick, Richard
2014-10-01
An in-depth investigation of the effect of a resonant error-field on a rotating, quasi-cylindrical, tokamak plasma is preformed within the context of resistive-MHD theory. General expressions for the response of the plasma at the rational surface to the error-field are derived in both the linear and nonlinear regimes, and the extents of these regimes mapped out in parameter space. Torque-balance equations are also obtained in both regimes. These equations are used to determine the steady-state plasma rotation at the rational surface in the presence of the error-field. It is found that, provided the intrinsic plasma rotation is sufficiently large, the torque-balance equations possess dynamically stable low-rotation and high-rotation solution branches, separated by a forbidden band of dynamically unstable solutions. Moreover, bifurcations between the two stable solution branches are triggered as the amplitude of the error-field is varied. A low- to high-rotation bifurcation is invariably associated with a significant reduction in the width of the magnetic island chain driven at the rational surface, and vice versa. General expressions for the bifurcation thresholds are derived, and their domains of validity mapped out in parameter space. This research was funded by the U.S. Department of Energy under Contract DE-FG02-04ER-54742.
Power accounting of plasma discharges in the linear device Proto-MPEX
Showers, M.; Piotrowicz, P. A.; Beers, C. J.; Biewer, T. M.; Caneses, J.; Canik, J.; Caughman, J. B. O.; Donovan, D. C.; Goulding, R. H.; Lumsdaine, A.; Kafle, N.; Owen, L. W.; Rapp, J.; Ray, H.
2018-06-01
Plasma material interaction (PMI) studies are crucial to the successful development of future fusion reactors. Prototype Material Plasma Exposure eXperiment (Proto-MPEX) is a prototype design for the MPEX, a steady-state linear device being developed to study PMI. The primary purpose of Proto-MPEX is developing the plasma heating source concepts for MPEX. A power accounting study of Proto-MPEX works to identify machine operating parameters that could improve its performance, thereby increasing its PMI research capabilities, potentially impacting the MPEX design concept. To build a comprehensive power balance, an analysis of the helicon region has been performed implementing a diagnostic suite and software modeling to identify mechanisms and locations of heat loss from the main plasma. Of the 106.3 kW of input power, up to 90.5% of the power has been accounted for in the helicon region. When the analysis was extended to encompass the device to its end plates, 49.2% of the input power was accounted for and verified diagnostically. Areas requiring further diagnostic analysis are identified. The required improvements will be implemented in future work. The data acquisition and analysis processes will be streamlined to form a working model for future power balance studies of Proto-MPEX. ).
Eck, van H.J.N.; Hansen, T.A.R.; Kleyn, A.W.; Meiden, van der H.J.; Schram, D.C.; Zeijlmans van Emmichoven, P.A.
2011-01-01
Magnum-PSI is a linear plasma generator designed to reach the plasma–surface interaction (PSI) regime of ITER and nuclear fusion reactors beyond ITER. To reach this regime, the influx of cold neutrals from the source must be significantly lower than the plasma flux reaching the target. This is
Khan, Masood [Department of Mathematics, Quaid-i-Azam University, Islamabad 44000 (Pakistan); Hashim, E-mail: hashim_alik@yahoo.com [Department of Mathematics, Quaid-i-Azam University, Islamabad 44000 (Pakistan); Hussain, M. [Department of Sciences and Humanities, National University of Computer and Emerging Sciences, Islamabad 44000 (Pakistan); Azam, M. [Department of Mathematics, Quaid-i-Azam University, Islamabad 44000 (Pakistan)
2016-08-15
This paper presents a study of the magnetohydrodynamic (MHD) boundary layer flow of a non-Newtonian Carreau fluid over a convectively heated surface. The analysis of heat transfer is further performed in the presence of non-linear thermal radiation. The appropriate transformations are employed to bring the governing equations into dimensionless form. The numerical solutions of the partially coupled non-linear ordinary differential equations are obtained by using the Runge-Kutta Fehlberg integration scheme. The influence of non-dimensional governing parameters on the velocity, temperature, local skin friction coefficient and local Nusselt number is studied and discussed with the help of graphs and tables. Results proved that there is significant decrease in the velocity and the corresponding momentum boundary layer thickness with the growth in the magnetic parameter. However, a quite the opposite is true for the temperature and the corresponding thermal boundary layer thickness. - Highlights: • We investigated the Magnetohydrodynamic flow of Carreau constitutive fluid model. • Impact of non-linear thermal radiation is further taken into account. • Runge-Kutta Fehlberg method is employed to obtain the numerical solutions. • Fluid velocity is higher in case of hydromagnetic flow in comparison with hydrodynamic flow. • The local Nusselt number is a decreasing function of the thermal radiation parameter.
Equilibrium, stability and heating of plasmas in linear and toroidal Extrap pinches
Bonnevier, B.; Drake, J.R.; Dalhed, H.E.
1983-01-01
The Extrap scheme consists of a Z-pinch immersed in an octupole field. The total magnetic field has no component along the pinch axis. Globally stable Z-pinch equilibria with a distributed plasma current density and a duration of about 100 Alfven transit times have been observed in linear and toroidal sector experiments. Theoretical studies indicate that this stability can be the result of constraints introduced by the octupole field and the resulting separatrix of the total field, in combination with finite-Larmor-radius effects. A scheme for ICRF heating of the plasma in configurations with a magnetic neutral line, being applicable to Extrap and FRC, is analysed. Wave propagation arises owing to the Hall effect. Particle resonances are responsible for the absorption, owing to a high parallel wavenumber and a weak magnetic field. (author)
Fields of an ultrashort tightly focused radially polarized laser pulse in a linear response plasma
Salamin, Yousef I.
2017-10-01
Analytical expressions for the fields of a radially polarized, ultrashort, and tightly focused laser pulse propagating in a linear-response plasma are derived and discussed. The fields are obtained from solving the inhomogeneous wave equations for the vector and scalar potentials, linked by the Lorenz gauge, in a plasma background. First, the scalar potential is eliminated using the gauge condition, then the vector potential is synthesized from Fourier components of an initial uniform distribution of wavenumbers, and the inverse Fourier transformation is carried out term-by-term in a truncated series (finite sum). The zeroth-order term in, for example, the axial electric field component is shown to model a pulse much better than its widely used paraxial approximation counterpart. Some of the propagation characteristics of the fields are discussed and all fields are shown to have manifested the expected limits for propagation in a vacuum.
On the non-linear dynamics of potential relaxation oscillations in bounded plasmas
Krssak, M.; Skalny, J.D.; Gyergyek, T.; Cercek, M.
2007-01-01
Plasma in a 1-dimensional diode is studied theoretically and the computer simulations are used for verification of the theoretical model. When collector in the diode is biased positively, a double-layer is created in the system and consequently, we are able to observe oscillations of the potential, density and other plasma parameters. When external periodic forcing is applied, spectra of these oscillations are changed and effects of synchronisation and periodic pulling can be observed. Both of these effects are of non-linear nature and a good explanation is found using the analogy with Van der Pol oscillators. Following [1] and [2] approximate analytical solutions are found and then compared with computer simulations obtained using a 1-dimensional particle-in-cell code XPDP1. (author)
Srivastava, Abhishek; Waterhouse, David; Ardrey, Alison; Ward, Stephen A
2012-11-01
A highly sensitive and rapid liquid chromatography tandem mass spectrometry (LC-MS/MS) method has been developed to measure the levels of the antitubercular drug rifampicin (RIF) in human plasma and cerebrospinal fluid (CSF). The analyte and internal standard (IS) were isolated from plasma and CSF by a simple organic solvent based precipitation of proteins followed by centrifugation. Detection was carried out by electrospray positive ionization mass spectrometry in the multiple-reaction monitoring (MRM) mode. The assay was linear in the concentration range 25-6400 ng/mL with intra- and inter-day precision of <7% and <8%, respectively. The validated method was applied to the study of RIF pharmacokinetics in human CSF and plasma over 25 h period after a 10 mg/kg oral dose. Copyright © 2012 Elsevier B.V. All rights reserved.
Guede, Jose Ricardo Abalde
1995-11-01
The aim of this work is to study the nonlinear dynamics of Langmuir and electromagnetic waves in space plasmas. Firstly, the generalized Zakharov equations are derived which are used to study the hybrid parametric instability involving the generation of daughter Langmuir, electromagnetic and ion-acoustic waves induced by two counter-propagating Langmuir pump waves with different amplitudes based on a coupled dispersion relation. Secondly, starting from the generalized Zakharov equations the linear and nonlinear coupled mode theories of three-wave and four-wave parametric interactions are developed, respectively. In three-waves processes, a Langmuir wave decays into another Langmuir wave and an ion-acoustic wave (electrostatic parametric decay) or into an electromagnetic wave and an ion-acoustic wave (electromagnetic parametric decay). In four-wave (modulational) processes, the interaction involves two wave triplets: in the decay triplet a pump wave couples with a low-frequency wave to generate a Stokes wave, and in the fusion triplets: in the decay triplet a pump wave couples with a low-frequency wave to generate a Stokes wave, and in the fusion triplet the coupling of a pump wave with a low-frequency wave generate an anti-Stokes wave. These modulational processes are convective and resonant processes wherein the low-frequency modes are Eigenmodes of plasma and are known as the stimulated modulational processes. Four such processes are investigated in this thesis: two with Langmuir pump waves (electrostatic and hybrid stimulated modulation processes) and the other two with electromagnetic pump waves (stimulated modulation Brillouin scattering and electromagnetic stimulated modulation process). Applications of the theoretical results in space plasmas are discussed. In particular, it is shown that the electrostatic and electromagnetic parametric decay processes of Langmuir waves can model the generation and modulation of radio emissions and Langmuir waves in the
Henriksen, Jens Henrik Sahl
1980-01-01
The variability of hydrostatic hepatic vein and ascitic fluid pressures and of plasma and ascitic fluid colloid osmotic (oncotic) pressures was assessed during hepatic venous catheterization by repeated measurements on different days and at different locations in patients with cirrhosis...... of the liver. Furthermore, calculation of oncotic pressure from protein determinations was compared to the directly measured value of plasma and ascitic fluid samples. Repeated measurements of hydrostatic pressure in the same hepatic vein within 15 min showed a standard deviation (SD) below 1 mm......Hg. The variation in hydrostatic hepatic vein pressures, pressure differences and ascitic fluid pressures (when measured at different locations within the liver and peritoneal space during a single examination) was 1.5, 1.0 and 1.0 mmHg (SD), respectively. When measured on different days, the variation...
Adams, Allan; Carr, Lincoln D.; Schaefer, Thomas; Steinberg, Peter; Thomas, John E.
2013-04-01
The last few years have witnessed a dramatic convergence of three distinct lines of research concerned with different kinds of extreme quantum matter. Two of these involve new quantum fluids that can be studied in the laboratory, ultracold quantum gases and quantum chromodynamics (QCD) plasmas. Even though these systems involve vastly different energy scales, the physical properties of the two quantum fluids are remarkably similar. The third line of research is based on the discovery of a new theoretical tool for investigating the properties of extreme quantum matter, holographic dualties. The main goal of this focus issue is to foster communication and understanding between these three fields. We proceed to describe each in more detail. Ultracold quantum gases offer a new paradigm for the study of nonperturbative quantum many-body physics. With widely tunable interaction strength, spin composition, and temperature, using different hyperfine states one can model spin-1/2 fermions, spin-3/2 fermions, and many other spin structures of bosons, fermions, and mixtures thereof. Such systems have produced a revolution in the study of strongly interacting Fermi systems, for example in the Bardeen-Cooper-Schrieffer (BCS) to Bose-Einstein condensate (BEC) crossover region, where a close collaboration between experimentalists and theorists—typical in this field—enabled ground-breaking studies in an area spanning several decades. Half-way through this crossover, when the scattering length characterizing low-energy collisions diverges, one obtains a unitary quantum gas, which is universal and scale invariant. The unitary gas has close parallels in the hydrodynamics of QCD plasmas, where the ratio of viscosity to entropy density is extremely low and comparable to the minimum viscosity conjecture, an important prediction of AdS/CFT (see below). Exciting developments in the thermodynamic and transport properties of strongly interacting Fermi gases are of broad
Neuroactive steroid levels in plasma and cerebrospinal fluid of male multiple sclerosis patients.
Caruso, Donatella; Melis, Marta; Fenu, Giuseppe; Giatti, Silvia; Romano, Simone; Grimoldi, Maria; Crippa, Donatella; Marrosu, Maria Giovanna; Cavaletti, Guido; Melcangi, Roberto Cosimo
2014-08-01
Neuroactive steroid family includes molecules synthesized in peripheral glands (i.e., hormonal steroids) and directly in the nervous system (i.e., neurosteroids) which are key regulators of the nervous function. As already reported in clinical and experimental studies, neurodegenerative diseases affect the levels of neuroactive steroids. However, a careful analysis comparing the levels of these molecules in cerebrospinal fluid (CSF) and in plasma of multiple sclerosis (MS) patients is still missing. To this aim, the levels of neuroactive steroids were evaluated by liquid chromatography-tandem mass spectrometry in CSF and plasma of male adults affected by Relapsing-Remitting MS and compared with those collected in control patients. An increase in pregnenolone and isopregnanolone levels associated with a decrease in progesterone metabolites, dihydroprogesterone, and tetrahydroprogesterone was observed in CSF of MS patients. Moreover, an increase of 5α-androstane-3α,17β-diol and of 17β-estradiol levels associated with a decrease of dihydrotestosterone also occurred. In plasma, an increase in pregnenolone, progesterone, and dihydrotestosterone and a decrease in dihydroprogesterone and tetrahydroprogesterone levels were reported. This study shows for the first time that the levels of several neuroactive steroids, and particularly those of progesterone and testosterone metabolites, are deeply affected in CSF of relapsing-remitting MS male patients. We here demonstrated that, the cerebrospinal fluid and plasma levels of several neuroactive steroids are modified in relapsing remitting multiple sclerosis male patients. Interestingly, we reported for the first time that, the levels of progesterone and testosterone metabolites are deeply affected in cerebrospinal fluid. These findings may have an important relevance in therapeutic and/or diagnostic field of multiple sclerosis. © 2014 International Society for Neurochemistry.
Equations for the non linear evolution of the resistive tearing modes in toroidal plasmas
Edery, D.; Pellat, R.; Soule, J.L.
1979-09-01
Following the tokamak ordering, we simplify the resistive MHD equations in toroidal geometry. We obtain a closed system of non linear equations for two scalar potentials of the magnetic and velocity fields and for plasma density and temperature. If we expand these equations in the inverse of aspect ratio they are exact to the two first orders. Our formalism should correctly describe the mode coupling by curvature effects /1/ and the toroidal displacement of magnetic surfaces /2/. It provides a natural extension of the well known cylindrical model /3/ and is now being solved on computer
England, W.B.
1978-01-01
Uncorrelated and correlated potential energy curves and dipole moments are reported for linear KOH. The compound is found to be ionic, K + OH - . Minimum energy bond lengths are R/sub KO/=4.2913 au and R/sub OH/=1.7688 au, with an estimated accuracy of 2%. The corresponding dipole moment is 3.3 au (8.46 D) with a similar accuracy estimate. This is to our knowledge the first value ever reported for the KOH dipole moment, and the large value suggests that KOH will be an effective electron scatterer in MHD plasmas
Yu, Dae Jung; Lee, Dong-Hun [School of Space Research, Kyung Hee University, Yongin (Korea, Republic of); Kim, Kihong [Division of Energy Systems Research, Ajou University, Suwon (Korea, Republic of)
2013-06-15
We study theoretically the linear mode conversion between electromagnetic waves and Langmuir waves in warm, stratified, and unmagnetized plasmas, using a numerically precise calculation based on the invariant imbedding method. We verify that the principle of reciprocity for the forward and backward mode conversion coefficients holds precisely regardless of temperature. We also find that the temperature dependence of the mode conversion coefficient is substantially stronger than that previously reported. Depending on the wave frequency and the incident angle, the mode conversion coefficient is found to increase or decrease with the increase of temperature.
A linear ion optics model for extraction from a plasma ion source
Dietrich, J.
1987-01-01
A linear ion optics model for ion extraction from a plasma ion source is presented, based on the paraxial equations which account for lens effects, space charge and finite source ion temperature. This model is applied to three- and four-electrode extraction systems with circular apertures. The results are compared with experimental data and numerical calculations in the literature. It is shown that the improved calculations of space charge effects and lens effects allow better agreement to be obtained than in earlier linear optics models. A principal result is that the model presented here describes the dependence of the optimum perveance on the aspect ratio in a manner similar to the nonlinear optics theory. (orig.)
Linear and nonlinear dynamics of electron temperature gradient mode in non-Maxwellian plasmas
Zakir, U.; Qamar, A. [Institute of Physics and Electronics, University of Peshawar, Peshawar (Pakistan); Haque, Q. [Theoretical Plasma Physics Division, PINSTECH, Islamabad (Pakistan); National Centre for Physics, Islamabad (Pakistan)
2013-05-15
The effect of non-Maxwellian distributed ions on electron temperature gradient mode is investigated. The linear dispersion relation of η{sub e}−mode is obtained which shows that the behavior of this mode changes in the presence of superthermal ions. The growth rate of η{sub e}−mode driven linear instability is found and is observed to modify due to nonthermal ions. However, it is found that this leaves the electron energy transport coefficient unchanged. In the nonlinear regime, a dipolar vortex solution is derived which indicates that the dynamic behavior of the vortices changes with the inclusion of kappa distributed ions. The importance of present study with respect to space and laboratory plasmas is also pointed out.
Integrable, oblique travelling waves in quasi-charge-neutral two-fluid plasmas
G. M. Webb
2008-02-01
Full Text Available A Hamiltonian description of oblique travelling waves in a two-fluid, charge-neutral, electron-proton plasma reveals that the transverse momentum equations for the electron and proton fluids are exactly integrable in cases where the total transverse momentum flux integrals, P_{y}^{(d} and P_{z}^{(d}, are both zero in the de Hoffman Teller (dHT frame. In this frame, the transverse electric fields are zero, which simplifies the transverse momentum equations for the two fluids. The integrable travelling waves for the case P_{y}^{(d}=P_{z}^{(d}=0, are investigated based on the Hamiltonian trajectories in phase space, and also on the longitudinal structure equation for the common longitudinal fluid velocity component u_{x} of the electron and proton fluids. Numerical examples of a variety of travelling waves in a cold plasma, including oscillitons, are used to illustrate the physics. The transverse, electron and proton velocity components u_{jy} and u_{jz} (j=e, p of the waves exhibit complex, rosette type patterns over several periods for u_{x}. The role of separatrices in the phase space, the rotational integral and the longitudinal structure equation on the different wave forms are discussed.
K. Ganesh Kumar
Full Text Available A mathematical analysis of two-phase boundary layer flow and heat transfer of a Williamson fluid with fluid particle suspension over a stretching sheet has been carried out in this paper. The region of temperature jump and nonlinear thermal radiation is considered in the energy transfer process. The principal equations of boundary layer flow and temperature transmission are reformed to a set of non-linear ordinary differential equations under suitable similarity transformations. The transfigured equalities are solved numerically with the help of RKF-45 order method. The effect of influencing parameters on velocity and temperature transfer of fluid is examined and deliberated by plotted graphs and tabulated values. Significances of the mass concentration of dust particle parameter play a key role in controlling flow and thermal behavior of non-Newtonian fluids. Further, the temperature and concern boundary layer girth are declines for increasing values of Williamson parameter. Keywords: Two-phase flow, Williamson fluid, Nonlinear thermal radiation, Magnetic field, Temperature jump
Coste, Ph.; Aubert, J.; Lejeune, C.
1991-01-01
The extensive development of ion beam technologies in the last years, in particular for thin film deposition and etching, poses the problem of predicting the behaviour of the ion beam from convenient models. One of the existing models, the 'perfect linear model', is easy to use and provides information about the geometrical parameters of the ion beam envelope. In this model, however, the plasma potential must be close to the plasma electrode potential. Now, ion sources with electrostatic containment of the ionizing electrons -very attractive because of their improved ionization efficiency - have a plasma potential higher than the plasma electrode potential. Thus, a space-charge sheath with a non-negligible thickness exists, which modifies the equilibrium conditions of the plasma meniscus and, therefore, the initial divergence of the ion beam. In this paper an adaptation of the perfect linear model for ion beam formation to the case of plasma sources with electron electrostatic containment is presented. (author)
Generalized fluid equations for parallel transport in collisional to weakly collisional plasmas
Zawaideh, E.S.
1985-01-01
A new set of two-fluid equations which are valid from collisional to weakly collisional limits are derived. Starting from gyrokinetic equations in flux coordinates with no zeroth order drifts, a set of moment equations describing plasma transport along the field lines of a space and time dependent magnetic field are derived. No restriction on the anisotropy of the ion distribution function is imposed. In the highly collisional limit, these equations reduce to those of Braginskii while in the weakly collisional limit, they are similar to the double adiabatic or Chew, Goldberger, and Low (CGL) equations. The new transport equations are used to study the effects of collisionality, magnetic field structure, and plasma anisotropy on plasma parallel transport. Numerical examples comparing these equations with conventional transport equations show that the conventional equations may contain large errors near the sound speed (M approx. = 1). It is also found that plasma anisotropy, which is not included in the conventional equations, is a critical parameter in determining plasma transport in varying magnetic field. The new transport equations are also used to study axial confinement in multiple mirror devices from the strongly to weakly collisional regime. A new ion conduction model was worked out to extend the regime of validity of the transport equations to the low density multiple mirror regime
Lau, Y.T.; Novakovskii, S.V.; Drake, J.F.
1996-01-01
We will present 2D linear and 3D nonlinear studies of resistive-ballooning modes in tokamak edge plasmas which include a closed flux region, as well as a limiter scrape-off layer (SOL) region. These studies therefore go beyond most earlier work, where the stability of the edge in the closed flux region and in the SOL have been considered separately. A 2D linear code, 2D-BALLOON, examines the stability of these curvature driven modes and provides the complete 2D eigenfunction spanning the closed flux surface region as well the open field line region. The sheath boundary condition in the SOL introduces an important new parameter λ = (m e /m i ) 1/2 v ei qR/v Te . This parameter plays a significant role in determining the stability of these modes in both the closed flux and SOL regions because of the radial coupling across the last closed flux surface (LCFS). For small λ the spectrum of unstable modes is broad and extends into the low toroidal mode number exclamation point regime where the spatial structure is flute-like. The amplitude for these modes is larger in the SOL compared to the closed flux region. However when A is increased, the low mode numbers are strongly stabilized and the high mode numbers which are strongly ballooning are the dominant modes. In this regime the radial modes straddle the LCFS. In both these cases, the variation in the plasma density is necessary for the radial localization. In the three-dimensional nonlinear simulations, we have solved a set of fluid equations in a toroidal geometry with both the closed flux region and the SOL. The introduction of the SOL to the twisted tube for the closed flux region, has been a major addition to our 3D code. We find that the turbulent transport in the SOL drops significantly as A is increased, which is consistent with our expectations from the 2D linear code results
A conservative finite difference method for the numerical solution of plasma fluid equations
Colella, P.; Dorr, M.R.; Wake, D.D.
1999-01-01
This paper describes a numerical method for the solution of a system of plasma fluid equations. The fluid model is similar to those employed in the simulation of high-density, low-pressure plasmas used in semiconductor processing. The governing equations consist of a drift-diffusion model of the electrons, together with an internal energy equation, coupled via Poisson's equation to a system of Euler equations for each ion species augmented with electrostatic force, collisional, and source/sink terms. The time integration of the full system is performed using an operator splitting that conserves space charge and avoids dielectric relaxation timestep restrictions. The integration of the individual ion species and electrons within the time-split advancement is achieved using a second-order Godunov discretization of the hyperbolic terms, modified to account for the significant role of the electric field in the propagation of acoustic waves, combined with a backward Euler discretization of the parabolic terms. Discrete boundary conditions are employed to accommodate the plasma sheath boundary layer on underresolved grids. The algorithm is described for the case of a single Cartesian grid as the first step toward an implementation on a locally refined grid hierarchy in which the method presented here may be applied on each refinement level
Fluid simulation of the conduction phase of the plasma erosion opening switch
Grossmann, J.M.; Mosher, D.; Ottinger, P.F.
1987-01-01
The conduction phase of the plasma erosion openings switch (PEOS) is studied using a 1 1/2-D electromagnetic two-fluid code. The focus of this work is on understanding how two effects, a current-limiting model of electron emission, and the magnetic insulation of electrons at the cathode, determine current conduction in the plasma. Simulations are performed in the parameter regimes of the Gamble I, POP, and PBFA II pulsed power generators, and previous low-density, short-rise time simulations of the PEOS. Fluid code results are compared to a 1-D analytic theory and to the Gamble I and POP experiments. Good agreement between theory and simulation, but mixed agreement between simulation and experiment is found. Experimental Β-field measurements on POP show weaker j x Β compression than the simulation. Current penetration and plasma current channels qualitatively similar to experimental observation are found in the Gamble I regime. However, magnetic insulation of electrons emitted from the cathode bunches the electron flow into narrower current channels than observed experimentally. In several cases, the presence of an electron-scattering or energy-loss mechanism near the cathode must be invoked to overcome magnetic insulation and widen the current channels
Boundary conditions for plasma fluid models at the magnetic presheath entrance
Loizu, J.; Ricci, P.; Halpern, F. D.; Jolliet, S.
2012-01-01
The proper boundary conditions at the magnetic presheath entrance for plasma fluid turbulence models based on the drift approximation are derived, focusing on a weakly collisional plasma sheath with T i ≪T e and a magnetic field oblique to a totally absorbing wall. First, the location of the magnetic presheath entrance is rigorously derived. Then boundary conditions at the magnetic presheath entrance are analytically deduced for v ||i , v ||e , n, φ, T e , and for the vorticity ω=∇ ⊥ 2 φ. The effects of E × B and diamagnetic drifts on the boundary conditions are also investigated. Kinetic simulations are performed that confirm the analytical results. Finally, the new set of boundary conditions is implemented in a three-dimensional global fluid code for the simulation of plasma turbulence and, as an example, the results of a tokamak scrape-off layer simulation are discussed. The framework presented can be generalized to obtain boundary conditions at the magnetic presheath entrance in more complex scenarios.
Computational modeling of fully-ionized, magnetized plasmas using the fluid approximation
Schnack, Dalton
2005-10-01
Strongly magnetized plasmas are rich in spatial and temporal scales, making a computational approach useful for studying these systems. The most accurate model of a magnetized plasma is based on a kinetic equation that describes the evolution of the distribution function for each species in six-dimensional phase space. However, the high dimensionality renders this approach impractical for computations for long time scales in relevant geometry. Fluid models, derived by taking velocity moments of the kinetic equation [1] and truncating (closing) the hierarchy at some level, are an approximation to the kinetic model. The reduced dimensionality allows a wider range of spatial and/or temporal scales to be explored. Several approximations have been used [2-5]. Successful computational modeling requires understanding the ordering and closure approximations, the fundamental waves supported by the equations, and the numerical properties of the discretization scheme. We review and discuss several ordering schemes, their normal modes, and several algorithms that can be applied to obtain a numerical solution. The implementation of kinetic parallel closures is also discussed [6].[1] S. Chapman and T.G. Cowling, ``The Mathematical Theory of Non-Uniform Gases'', Cambridge University Press, Cambridge, UK (1939).[2] R.D. Hazeltine and J.D. Meiss, ``Plasma Confinement'', Addison-Wesley Publishing Company, Redwood City, CA (1992).[3] L.E. Sugiyama and W. Park, Physics of Plasmas 7, 4644 (2000).[4] J.J. Ramos, Physics of Plasmas, 10, 3601 (2003).[5] P.J. Catto and A.N. Simakov, Physics of Plasmas, 11, 90 (2004).[6] E.D. Held et al., Phys. Plasmas 11, 2419 (2004)
Fructose levels are markedly elevated in cerebrospinal fluid compared to plasma in pregnant women.
Janice J Hwang
Full Text Available Fructose, unlike glucose, promotes feeding behavior in rodents and its ingestion exerts differential effects in the human brain. However, plasma fructose is typically 1/1000 th of glucose levels and it is unclear to what extent fructose crosses the blood-brain barrier. We investigated whether local endogenous central nervous system (CNS fructose production from glucose via the polyol pathway (glucose → sorbitol → fructose contributes to brain exposure to fructose.In this observational study, fasting glucose, sorbitol and fructose concentrations were measured using gas-chromatography-liquid mass spectroscopy in cerebrospinal fluid (CSF, maternal plasma, and venous cord blood collected from 25 pregnant women (6 lean, 10 overweight/obese, and 9 T2DM/gestational DM undergoing spinal anesthesia and elective cesarean section.As expected, CSF glucose was ~ 60% of plasma glucose levels. In contrast, fructose was nearly 20-fold higher in CSF than in plasma (p < 0.001, and CSF sorbitol was ~ 9-times higher than plasma levels (p < 0.001. Moreover, CSF fructose correlated positively with CSF glucose (ρ 0.45, p = 0.02 and sorbitol levels (ρ 0.75, p < 0.001. Cord blood sorbitol was also ~ 7-fold higher than maternal plasma sorbitol levels (p = 0.001. There were no differences in plasma, CSF, and cord blood glucose, fructose, or sorbitol levels between groups.These data raise the possibility that fructose may be produced endogenously in the human brain and that the effects of fructose in the human brain and placenta may extend beyond its dietary consumption.
Fructose levels are markedly elevated in cerebrospinal fluid compared to plasma in pregnant women.
Hwang, Janice J; Johnson, Andrea; Cline, Gary; Belfort-DeAguiar, Renata; Snegovskikh, Denis; Khokhar, Babar; Han, Christina S; Sherwin, Robert S
2015-01-01
Fructose, unlike glucose, promotes feeding behavior in rodents and its ingestion exerts differential effects in the human brain. However, plasma fructose is typically 1/1000 th of glucose levels and it is unclear to what extent fructose crosses the blood-brain barrier. We investigated whether local endogenous central nervous system (CNS) fructose production from glucose via the polyol pathway (glucose → sorbitol → fructose) contributes to brain exposure to fructose. In this observational study, fasting glucose, sorbitol and fructose concentrations were measured using gas-chromatography-liquid mass spectroscopy in cerebrospinal fluid (CSF), maternal plasma, and venous cord blood collected from 25 pregnant women (6 lean, 10 overweight/obese, and 9 T2DM/gestational DM) undergoing spinal anesthesia and elective cesarean section. As expected, CSF glucose was ~ 60% of plasma glucose levels. In contrast, fructose was nearly 20-fold higher in CSF than in plasma (p < 0.001), and CSF sorbitol was ~ 9-times higher than plasma levels (p < 0.001). Moreover, CSF fructose correlated positively with CSF glucose (ρ 0.45, p = 0.02) and sorbitol levels (ρ 0.75, p < 0.001). Cord blood sorbitol was also ~ 7-fold higher than maternal plasma sorbitol levels (p = 0.001). There were no differences in plasma, CSF, and cord blood glucose, fructose, or sorbitol levels between groups. These data raise the possibility that fructose may be produced endogenously in the human brain and that the effects of fructose in the human brain and placenta may extend beyond its dietary consumption.
McKenzie, J. F.; Dubinin, E.; Sauer, K.; Doyle, T. B.
2004-08-01
Perturbation reductive procedures, as used to analyse various weakly nonlinear plasma waves (solitons and periodic waves), normally lead to the dynamical system being described by KdV, Burgers' or a nonlinear Schrödinger-type equation, with properties that can be deduced from an array of mathematical techniques. Here we develop a fully nonlinear theory of one-dimensional stationary plasma waves, which elucidates the common nature of various diverse wave phenomena. This is accomplished by adopting an essentially fluid dynamic viewpoint. In this unified treatment the constants of the motion (for mass, momentum and energy) lead naturally to the construction of the wave structure equations. It is shown, for example, that electrostatic, Hall magnetohydrodynamic and ion cyclotron acoustic nonlinear waves all obey first-order differential equations of the same generic type for the longitudinal flow field of the wave. The equilibrium points, which define the soliton amplitude, are given by the compressive and/or rarefactive roots of a total plasma ‘energy’ or ‘momentum’ function characterizing the wave type. This energy function, which is an algebraic combination of the Bernoulli momentum and energy functions for the longitudinal flow field, is the fluid dynamic counterpart of the pseudo-potentials, which are characteristic of system structure equations formulated in other than fluid variables. Another general feature of the structure equation is the phenomenon of choked flow, which occurs when the flow speed becomes sonic. It is this trans-sonic property that limits the soliton amplitudes and defines the critical collective Mach numbers of the waves. These features are also obtained in multi-component plasmas where, for example, in a bi-ion plasma, momentum exchanges between protons and heavier ions are mediated by the Maxwell magnetic stresses. With a suitable generalization of the concept of a sonic point in a bi-ion system and the corresponding choked flow
Density Transition Based Self-Focusing of cosh-Gaussian Laser Beam in Plasma with Linear Absorption
Kant, Niti; Wani, Manzoor Ahmad
2015-01-01
Density transition based self-focusing of cosh-Gaussian laser beam in plasma with linear absorption has been studied. The field distribution in the plasma is expressed in terms of beam width parameter, decentered parameter, and linear absorption coefficient. The differential equation for the beam width parameter is solved by following Wentzel–Kramers–Brillouin (WKB) and paraxial approximation through parabolic wave equation approach. The behaviour of beam width parameter with dimensionless distance of propagation is studied at optimum values of plasma density, decentered parameter and with different absorption levels in the medium. The results reveal that these parameters can affect the self-focusing significantly. (paper)
Validation study of a drift-wave turbulence model for CSDX linear plasma device
Vaezi, P.; Holland, C.; Thakur, S. C.; Tynan, G. R.
2017-09-01
A validation study of self-regulating drift-wave turbulence/zonal flow dynamics in the Controlled Shear Decorrelation Experiment linear plasma device using Langmuir probe synthetic diagnostics is presented in this paper. We use a set of nonlocal 3D equations, which evolve density, vorticity, and electron temperature fluctuations, and include proper sheath boundary conditions. Nonlinear simulations of these equations are carried out using BOUndary Turbulence (BOUT++) framework. To identify the dominant parametric dependencies of the model, a linear growth rate sensitivity analysis is performed using input parameter uncertainties, which are taken from the experimental measurements. For the direct comparison of nonlinear simulation results to experiment, we use synthetic Langmuir probe diagnostics to generate a set of synthetic ion saturation current and floating potential fluctuations. In addition, comparisons of azimuthal velocities determined via time-delay estimation, and nonlinear energy transfer are shown. We observe a significant improvement of model-experiment agreement relative to the previous 2D simulations. An essential component of this improved agreement is found to be the effect of electron temperature fluctuations on floating potential measurements, which introduces clear amplitude and phase shifts relative to the plasma potential fluctuations in synthetically measured quantities, where the simulations capture the experimental measurements in the core of plasma. However, the simulations overpredict the fluctuation levels at larger radii. Moreover, systematic simulation scans show that the self-generated E × B zonal flows profile is very sensitive to the steepening of density equilibrium profile. This suggests that evolving both fluctuations and equilibrium profiles, along with the inclusion of modest axial variation of radial profiles in the model are needed for further improvement of simulation results against the experimental measurements.
Hamiltonian field description of two-dimensional vortex fluids and guiding center plasmas
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
Improving total-building seismic performance using linear fluid viscous dampers
Del Gobbo, GM; Blakeborough, A; Williams, MS
2018-01-01
Previous research has revealed that Eurocode-compliant structures can experience structural and nonstructural damage during earthquakes. Retrofitting buildings with fluid viscous dampers (FVDs) can improve interstorey drifts and floor accelerations, two structural parameters that characterize seismic demand. Previous research focusing on FVD applications for improving seismic performance has focused on structural performance. Structural parameters such as interstorey drifts and floor accelera...
On the linear problem arising from motion of a fluid around a moving rigid body
Nečasová, Šárka; Wolf, J.
2015-01-01
Roč. 140, č. 2 (2015), s. 241-259 ISSN 0862-7959 R&D Projects: GA ČR(CZ) GAP201/11/1304 Institutional support: RVO:67985840 Keywords : incompressible fluid * rotating rigid body * strong solution Subject RIV: BA - General Mathematics http://hdl.handle.net/10338.dmlcz/144329
Archambeau, C.B.
1994-01-01
A fractured solid under stress loading (or unloading) can be viewed as behaving macroscopically as a medium with internal, hidden, degrees of freedom, wherein changes in fracture geometry (i.e. opening, closing and extension) and flow of fluid and gas within fractures will produce major changes in stresses and strains within the solid. Likewise, the flow process within fractures will be strongly coupled to deformation within the solid through boundary conditions on the fracture surfaces. The effects in the solid can, in part, be phenomenologically represented as inelastic or plastic processes in the macroscopic view. However, there are clearly phenomena associated with fracture growth and open fracture fluid flows that produce effects that can not be described using ordinary inelastic phenomenology. This is evident from the fact that a variety of energy release phenomena can occur, including seismic emissions of previously stored strain energy due to fracture growth, release of disolved gas from fluids in the fractures resulting in enhanced buoyancy and subsequent energetic flows of gas and fluids through the fracture system which can produce raid extension of old fractures and the creation of new ones. Additionally, the flows will be modulated by the opening and closing of fractures due to deformation in the solid, so that the flow process is strongly coupled to dynamical processes in the surrounding solid matrix, some of which are induced by the flow itself
Study of a few problems concerning plasma physics and fluid mechanics
Colin, M.
2011-01-01
The works presented in this thesis deal with solving partial differential equations concerning the laser-plasma interaction and some issues in fluid mechanics. All these works involve significant research in the modelization field: the approximation of oscillating hyperbolic systems, the simulation of Zakharov-type systems involving the Raman effect, Hele-Shaw models and gigantic micelles models. They also tackles theoretical issues like the existence and the uniqueness of solutions, the stability or instability of solitary waves, the optimal control, error estimation and model convergency
Lyapunov stability and thermal stability of partially relaxed fluids and plasmas
Elsaesser, K.; Spiess, P.
1996-01-01
The relation between the Lyapunov stability of a Hamiltonian system and the thermal stability of a fluid whose temperature is controlled from outside is explored: The free energy as a functional of the correct variables (specific volume, local entropy, and some Clebsch potentials of the velocity) may serve as a Lyapunov functional, depending on the open-quote open-quote Casimirs close-quote close-quote as exchanged quantities. For a multi-species plasma one obtains a sufficient condition for stability: γ(v 2 /c 2 s )-1 s the sound speed. Some features of partially relaxed (T=const) cylindrical plasmas are also discussed. copyright 1996 American Institute of Physics
Hybrid Fluid/Kinetic Modeling Of Magnetized High Energy Density Plasmas
Hansen, David; Held, Eric; King, Jacob; Stoltz, Peter; Masti, Robert; Srinivasan, Bhuvana
2017-10-01
MHD modeling with an equation of state (EOS) of the Rayleigh-Taylor (RT) instabily in Z indicates that it is seeded by the electro-thermal instability. Large thermodynamic drives associated with gradients at the interface between the liner and the coronal regions distort distribution functions and likely lead to non-local transport effects in a plasma which varies from weakly to strongly coupled. In this work, we discuss using effective potential theory along with a Chapman-Ensksog-like (CEL) formalism to develop hybrid fluid/kinetic modeling capabilities for these plasmas. Effective potential theory addresses the role of Coulomb collisions on transport across coupling regimes and the CEL approach bridges the gap between full-blow kinetic simulations and the EOS tables, which only depend locally on density and temperature. Quantitative results on the Spitzer problem across coupling coupling regimes will be presented as a first step. DOE Grant No. DE-SC0016525.
Relativistic effects on large amplitude nonlinear Langmuir waves in a two-fluid plasma
Nejoh, Yasunori
1994-07-01
Large amplitude relativistic nonlinear Langmuir waves are analyzed by the pseudo-potential method. The existence conditions for nonlinear Langmuir waves are confirmed by considering relativistic high-speed electrons in a two-fluid plasma. The significant feature of this investigation is that the propagation of nonlinear Langmuir waves depends on the ratio of the electron streaming velocity to the velocity of light, the normalized potential and the ion mass to electron mass ratio. The constant energy is determined by the specific range of the relativistic effect. In the non-relativistic limit, large amplitude relativistic Langmuir waves do not exist. The present investigation predicts new findings of large amplitude nonlinear Langmuir waves in space plasma phenomena in which relativistic electrons are important. (author)
Noise analysis of fluid-valve system in a linear compressor using CAE
Lee, Jun Ho; Jeong, Weui Bong; Kim, Dang Ju
2009-01-01
A linear compressor in a refrigerator uses piston motion to transfer refrigerant so its efficiency is higher than a previous reciprocal compressor. Because of interaction between refrigerant and valves system in the linear compressor, however, noise has been a main issue. In spite of doing many experimental researches, there is no way to rightly predict the noise. In order to solve this limitation, the CAE analysis is applied. For giving credit to these computational data, all of the data are experimentally validated.
Yang, Xuemei; Li, Guoliang; Chen, Lingyun; Zhang, Cong; Wan, Xinxiang; Xu, Jiangping
2011-07-01
A rapid, sensitive and selective method was developed for the quantitative determination of hederagenin in rat plasma and cerebrospinal fluid (CSF) by ultra fast liquid chromatography-tandem mass spectrometry (UFLC-MS/MS). It has been successfully applied in a pharmacokinetic study of hederagenin in the central nervous system (CNS). Sample pretreatment involved a simple protein precipitation with methanol and a one-step extraction with ethyl acetate. Separation was carried out in a Shim-pack XR-ODS II (75 mm × 2.0 mm, i.d., 2.1 μm) column with gradient elution at a flow rate of 0.35 mL/min. The mobile phase was 5mM ammonium acetate and acetonitrile. Detection was performed in a triple-quadruple tandem mass spectrometer by multiple-reaction-monitoring mode via electrospray ionization. A linear calibration curve for hederagenin was obtained over a concentration range of 0.406 (lower limit of quantification, LLOQ) to 203 ng/mL (r² > 0.99) for both plasma and CSF. The intra-day and inter-day precision (relative standard deviation, RSD) values were less than 15%. At all quality control (QC) levels, the accuracy (relative error, RE) was within -9.0% and 11.1% for plasma and CSF, respectively. The pharmacokinetics results indicated that hederagenin could pass through the blood-brain barrier. This UFLC-MS/MS method demonstrates higher sensitivity and sample throughput than previous methods. It was also successfully applied to the pharmacokinetic study of hederagenin following oral administration of Fructus akebiae extract in rats. Copyright © 2011 Elsevier B.V. All rights reserved.
Lagrangian fluid description with simple applications in compressible plasma and gas dynamics
Schamel, Hans
2004-01-01
The Lagrangian fluid description, in which the dynamics of fluids is formulated in terms of trajectories of fluid elements, not only presents an alternative to the more common Eulerian description but has its own merits and advantages. This aspect, which seems to be not fully explored yet, is getting increasing attention in fluid dynamics and related areas as Lagrangian codes and experimental techniques are developed utilizing the Lagrangian point of view with the ultimate goal of a deeper understanding of flow dynamics. In this tutorial review we report on recent progress made in the analysis of compressible, more or less perfect flows such as plasmas and dilute gases. The equations of motion are exploited to get further insight into the formation and evolution of coherent structures, which often exhibit a singular or collapse type behavior occurring in finite time. It is argued that this technique of solution has a broad applicability due to the simplicity and generality of equations used. The focus is on four different topics, the physics of which being governed by simple fluid equations subject to initial and/or boundary conditions. Whenever possible also experimental results are mentioned. In the expansion of a semi-infinite plasma into a vacuum the energetic ion peak propagating supersonically towards the vacuum--as seen in laboratory experiments--is interpreted by means of the Lagrangian fluid description as a relic of a wave breaking scenario of the corresponding inviscid ion dynamics. The inclusion of viscosity is shown numerically to stabilize the associated density collapse giving rise to a well defined fast ion peak reminiscent of adhesive matter. In purely convection driven flows the Lagrangian flow velocity is given by its initial value and hence the Lagrangian velocity gradient tensor can be evaluated accurately to find out the appearance of singularities in density and vorticity and the emergence of new structures such as wavelets in one
Lagrangian fluid description with simple applications in compressible plasma and gas dynamics
Schamel, Hans
2004-03-01
The Lagrangian fluid description, in which the dynamics of fluids is formulated in terms of trajectories of fluid elements, not only presents an alternative to the more common Eulerian description but has its own merits and advantages. This aspect, which seems to be not fully explored yet, is getting increasing attention in fluid dynamics and related areas as Lagrangian codes and experimental techniques are developed utilizing the Lagrangian point of view with the ultimate goal of a deeper understanding of flow dynamics. In this tutorial review we report on recent progress made in the analysis of compressible, more or less perfect flows such as plasmas and dilute gases. The equations of motion are exploited to get further insight into the formation and evolution of coherent structures, which often exhibit a singular or collapse type behavior occurring in finite time. It is argued that this technique of solution has a broad applicability due to the simplicity and generality of equations used. The focus is on four different topics, the physics of which being governed by simple fluid equations subject to initial and/or boundary conditions. Whenever possible also experimental results are mentioned. In the expansion of a semi-infinite plasma into a vacuum the energetic ion peak propagating supersonically towards the vacuum-as seen in laboratory experiments-is interpreted by means of the Lagrangian fluid description as a relic of a wave breaking scenario of the corresponding inviscid ion dynamics. The inclusion of viscosity is shown numerically to stabilize the associated density collapse giving rise to a well defined fast ion peak reminiscent of adhesive matter. In purely convection driven flows the Lagrangian flow velocity is given by its initial value and hence the Lagrangian velocity gradient tensor can be evaluated accurately to find out the appearance of singularities in density and vorticity and the emergence of new structures such as wavelets in one-dimension (1D
Sérgio Monteiro de Almeida
2014-07-01
Full Text Available Increased plasma lactate levels can indicate the presence of metabolic disorders in HIV infected individuals. Objective: To determine whether a portable analyzer is valid for measuring cerebrospinal fluid (CSF and plasma lactate levels in HIV infected individuals. Method: CSF and plasma were collected from 178 subjects. Samples tested by the Accutrend® portable analyzer were compared to those tested by a reference device (SYNCHRON LX® 20. Results: The portable analyzer had in plasma sensitivity of 0.95 and specificity 0.87. For CSF the specificity was 0.95; the sensitivity 0.33; the negative predictive value was 95% and the positive predictive value 33%. Conclusions: These findings support the validity of the portable analyzer in measuring lactate concentrations in CSF that fall within the normal range. The relatively poor positive predictive value indicates that a result above the reference range may represent a “false positive test”, and should be confirmed by the reference device before concluding abnormality.
Xu Hui-Jing; Shu-Xia Zhao; Gao Fei; Zhang Yu-Ru; Li Xue-Chun; Wang You-Nian
2015-01-01
A new type of two-dimensional self-consistent fluid model that couples an equivalent circuit module is used to investigate the mode transition characteristics and hysteresis in hydrogen inductively coupled plasmas at different pressures, by varying the series capacitance of the matching box. The variations of the electron density, temperature, and the circuit electrical properties are presented. As cycling the matching capacitance, at high pressure both the discontinuity and hysteresis appear for the plasma parameters and the transferred impedances of both the inductive and capacitive discharge components, while at low pressure only the discontinuity is seen. The simulations predict that the sheath plays a determinative role on the presence of discontinuity and hysteresis at high pressure, by influencing the inductive coupling efficiency of applied power. Moreover, the values of the plasma transferred impedances at different pressures are compared, and the larger plasma inductance at low pressure due to less collision frequency, as analyzed, is the reason why the hysteresis is not seen at low pressure, even with a wider sheath. Besides, the behaviors of the coil voltage and current parameters during the mode transitions are investigated. They both increase (decrease) at the E to H (H to E) mode transition, indicating an improved (worsened) inductive power coupling efficiency. (paper)
Deng, Jing; Li, Yaojian; Xu, Yongxiang; Sheng, Hongzhi
2010-01-01
In this work, Magnetic Fluid dynamics (MHD) model is used to stimulate the electromagnetic field, heat transfer and fluid flow in a DC non-transferred arc plasma torch. Through the coupled iterative computation about the electromagnetic equations described by magnetic vector potential format and the modified fluid dynamics equations, the electric potential, temperature and velocity distributions in the torch are obtained. The fluid-solid coupled computation method is applied to treat the electric current and heat transfer at the interface between the electrodes and fluid. The location of arc root attachment at the inside surface of anode and the arc voltage of the torch that we have predicted are very consistent with the corresponding experimental results. The calculated results of the torch are applied to the numerical simulation of the plasma jets under the laminar and turbulent condition. (author)
A linear-field plasma jet for generating a brush-shaped laminar plume at atmospheric pressure
Li, Xuechen; Jia, Pengying, E-mail: plasmalab@126.com [College of Physics Science and Technology, Hebei University, Baoding 071002 (China); Key Laboratory of Photo-Electronics Information Materials of Hebei Province, Baoding 071002 (China); Li, Jiyuan; Chu, Jingdi; Zhang, Panpan [College of Physics Science and Technology, Hebei University, Baoding 071002 (China)
2016-06-15
A linear-field plasma jet composed of line-to-plate electrodes is used to generate a large-scale brush-shaped plasma plume with flowing argon used as working gas. Through electrical measurement and fast photography, it is found that the plasma plume bridges the two electrodes for the discharge in the positive voltage half-cycle, which behaves like fast moving plasma bullets directed from the anode to the cathode. Compared with the positive discharge, the negative discharge only develops inside the nozzle and propagates much slower. Results also indicate that the gas temperature of the plume is close to room temperature, which is promising for biomedical application.
Navarro, J. A.; Madariaga, J. A.; Santamaria, C. M.; Saviron, J. M.
1980-01-01
10 refs. Flow pattern calculations in natural convection between two vertical coaxial cylinders are reported. It is assumed trough the paper. that fluid properties, viscosity, thermal conductivity and density, depend no-linearly on temperature and that the aspects (height/radius) ratio of the cylinders is high. Velocity profiles are calculated trough a perturbative scheme and analytic results for the three first perturbation orders are presented. We outline also an iterative method to estimate the perturbations on the flow patterns which arise when a radial composition gradient is established by external forces in a two-component fluid. This procedure, based on semiempirical basis, is applied to gaseous convection. The influence of the molecules gas properties on tho flow is also discussed. (Author) 10 refs
X. Jiang
2017-08-01
Full Text Available Laser induced breakdown spectroscopy (LIBS is a strong candidate for detecting and monitoring the H/D/T content on the surface of plasma facing components (PFCs due to its capability of fast direct in situ measurement in extreme environment (e.g., vacuum, magnetic field, long distance, complex geometry. To study the feasibilities and encounter the challenges of LIBS on plasma devices, a LIBS system has been set up on the linear plasma device PSI-2. A number of key parameters including laser energy, the influence of magnetic field and the persistence of laser induced plasma are studied. Real-time measurements of deuterium outgassing on tungsten samples exposed to deuterium plasma of 1025 D/m2 are performed in the first 40–130 min after plasma exposure. The experimental results are compared to the calculations in the literature.
Londono, J.M.; Wagg, D.; Neild, S.A.
2014-01-01
Viscous fluid dampers have proved to be effective in suppressing unwanted vibrations in a range of engineering structures. When dampers are fitted in a structure, a brace is typically used to attach them to the main structure. The stiffness of this brace can significantly alter the effectiveness of the damper, and in structures with multiple dampers, this can be a complex scenario to model. In this paper, we demonstrate that the effects of the brace compliance on the damper performance can be...
Yan Zhang
2011-01-01
Full Text Available The problem of steady, laminar, thermal Marangoni convection flow of non-Newtonian power law fluid along a horizontal surface with variable surface temperature is studied. The partial differential equations are transformed into ordinary differential equations by using a suitable similarity transformation and analytical approximate solutions are obtained by an efficient transformation, asymptotic expansion and Padé approximants technique. The effects of power law index and Marangoni number on velocity and temperature profiles are examined and discussed.
Mehrdad Shahmohammadi Beni
2017-06-01
Full Text Available Cold plasmas were proposed for treatment of leukemia. In the present work, conceptual designs of mixing chambers that increased the contact between the two fluids (plasma and blood through addition of obstacles within rectangular-block-shaped chambers were proposed and the dynamic mixing between the plasma and blood were studied using the level set method coupled with heat transfer. Enhancement of mixing between blood and plasma in the presence of obstacles was demonstrated. Continuous tracking of fluid mixing with determination of temperature distributions was enabled by the present model, which would be a useful tool for future development of cold plasma devices for treatment of blood-related diseases such as leukemia.
Li, Zhaorui; Livescu, Daniel
2017-11-01
The two-fluid plasma equations with full transport terms, including temperature and magnetic field dependent ion and electron viscous stresses and heat fluxes, frictional drag force, and ohmic heating term have been solved by using the sixth-order non-dissipative compact scheme for plasma flows in several different regimes. In order to be able to fully resolve all the dynamically relevant time and length scales while maintaining computational feasibility, the assumptions of infinite speed of light and negligible electron inertia have been made. The accuracy and robustness of this two-fluid plasma solver in handling plasma flows have been tested against a series of canonical problems, such as Alfven-Whistler dispersion relation, electromagnetic plasma shock, magnetic reconnection, etc. For all test cases, grid convergence tests have been conducted to achieve fully resolved results. The roles of heat flux, viscosity, resistivity, Hall and Biermann battery effects, are investigated for the canonical flows studied.
Szili, Endre J.; Gaur, Nishtha; Hong, Sung-Ha; Kurita, Hirofumi; Oh, Jun-Seok; Ito, Masafumi; Mizuno, Akira; Hatta, Akimitsu; Cowin, Allison J.; Graves, David B.; Short, Robert D.
2017-07-01
There is a growing literature database that demonstrates the therapeutic potential of cold atmospheric plasma (herein referred to as plasma). Given the breadth of proposed applications (e.g. from teeth whitening to cancer therapy) and vast gamut of plasma devices being researched, it is timely to consider plasma interactions with specific components of the cell in more detail. Plasma can produce highly reactive oxygen and nitrogen species (RONS) such as the hydroxyl radical (OH•), peroxynitrite (ONOO-) and superoxide (\\text{O}2- ) that would readily modify essential biomolecules such as DNA. These modifications could in principle drive a wide range of biological processes. Against this possibility, the reported therapeutic action of plasmas are not underpinned by a particularly deep knowledge of the potential plasma-tissue, -cell or -biomolecule interactions. In this study, we aim to partly address this issue by developing simple models to study plasma interactions with DNA, in the form of DNA-strand breaks. This is carried out using synthetic models of tissue fluid, tissue and cells. We argue that this approach makes experimentation simpler, more cost-effective and faster than compared to working with real biological materials and cells. Herein, a helium plasma jet source was utilised for these experiments. We show that the plasma jet readily induced DNA-strand breaks in the tissue fluid model and in the cell model, surprisingly without any significant poration or rupture of the phospholipid membrane. In the plasma jet treatment of the tissue model, DNA-strand breaks were detected in the tissue mass after pro-longed treatment (on the time-scale of minutes) with no DNA-strand breaks being detected in the tissue fluid model underneath the tissue model. These data are discussed in the context of the therapeutic potential of plasma.
Revisiting the Landau fluid closure.
Hunana, P.; Zank, G. P.; Webb, G. M.; Adhikari, L.
2017-12-01
Advanced fluid models that are much closer to the full kinetic description than the usual magnetohydrodynamic description are a very useful tool for studying astrophysical plasmas and for interpreting solar wind observational data. The development of advanced fluid models that contain certain kinetic effects is complicated and has attracted much attention over the past years. Here we focus on fluid models that incorporate the simplest possible forms of Landau damping, derived from linear kinetic theory expanded about a leading-order (gyrotropic) bi-Maxwellian distribution function f_0, under the approximation that the perturbed distribution function f_1 is gyrotropic as well. Specifically, we focus on various Pade approximants to the usual plasma response function (and to the plasma dispersion function) and examine possibilities that lead to a closure of the linear kinetic hierarchy of fluid moments. We present re-examination of the simplest Landau fluid closures.
Papaseit, Esther; Farré, Magí; Graziano, Silvia; Pacifici, Roberta; Pérez-Mañá, Clara; García-Algar, Oscar; Pichini, Simona
2017-03-01
Electronic cigarettes (e-cig) known as electronic nicotine devices recently gained popularity among smokers. Despite many studies investigating their safety and toxicity, few examined the delivery of e-cig-derived nicotine and its metabolites in alternative biological fluids. We performed a randomized, crossover, and controlled clinical trial in nine healthy smokers. Nicotine (NIC), cotinine (COT), and trans-3'-hydroxycotinine (3-HCOT) were measured in plasma and oral fluid by liquid chromatography-tandem mass spectrometry after consumption of two consecutive e-cig administrations or two consecutive tobacco cigarettes. NIC and its metabolites were detected both in oral fluid and plasma following both administration conditions. Concentrations in oral fluid resulted various orders of magnitude higher than those observed in plasma. Oral fluid concentration of tobacco cigarette and e-cig-derived NIC peaked at 15 min after each administration and ranged between 1.0 and 1396 μg/L and from 0.3 to 860 μg/L; those of COT between 52.8 and 110 μg/L and from 33.8 to 94.7 μg/L; and those of 3-HCOT between 12.4 and 23.5 μg/L and from 8.5 to 24.4 μg/L. The oral fluid to plasma concentration ratio of both e-cig- and tobacco cigarette-derived NIC peaked at 15 min after both administrations and correlated with oral fluid NIC concentration. The obtained results support the measurement of NIC and metabolites in oral fluid in the assessment of intake after e-cig use and appear to be a suitable alternative to plasma when monitoring nicotine delivery from e-cig for clinical and toxicological studies.
Comparisons of linear and nonlinear plasma response models for non-axisymmetric perturbations
Turnbull, A. D.; Ferraro, N. M.; Lao, L. L.; Lanctot, M. J. [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States); Izzo, V. A. [University of California-San Diego, 9500 Gilman Dr., La Jolla, California 92093-0417 (United States); Lazarus, E. A.; Hirshman, S. P. [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831 (United States); Park, J.-K.; Lazerson, S.; Reiman, A. [Princeton Plasma Physics Laboratory, P.O. Box 451, Princeton, New Jersey 08543-0451 (United States); Cooper, W. A. [Association Euratom-Confederation Suisse, Centre de Recherches en Physique des Plasmas, Ecole Polytechnique Federale de Lausanne, Lausanne (Switzerland); Liu, Y. Q. [Culham Centre for Fusion Energy, Culham Science Centre, Abingdon, Oxfordshire, OX14 3DB (United Kingdom); Turco, F. [Columbia University, 116th St and Broadway, New York, New York 10027 (United States)
2013-05-15
With the installation of non-axisymmetric coil systems on major tokamaks for the purpose of studying the prospects of ELM-free operation, understanding the plasma response to the applied fields is a crucial issue. Application of different response models, using standard tools, to DIII-D discharges with applied non-axisymmetric fields from internal coils, is shown to yield qualitatively different results. The plasma response can be treated as an initial value problem, following the system dynamically from an initial unperturbed state, or from a nearby perturbed equilibrium approach, and using both linear and nonlinear models [A. D. Turnbull, Nucl. Fusion 52, 054016 (2012)]. Criteria are discussed under which each of the approaches can yield a valid response. In the DIII-D cases studied, these criteria show a breakdown in the linear theory despite the small 10{sup −3} relative magnitude of the applied magnetic field perturbations in this case. For nonlinear dynamical evolution simulations to reach a saturated nonlinear steady state, appropriate damping mechanisms need to be provided for each normal mode comprising the response. Other issues arise in the technical construction of perturbed flux surfaces from a displacement and from the presence of near nullspace normal modes. For the nearby equilibrium approach, in the absence of a full 3D equilibrium reconstruction with a controlled comparison, constraints relating the 2D system profiles to the final profiles in the 3D system also need to be imposed to assure accessibility. The magnetic helicity profile has been proposed as an appropriate input to a 3D equilibrium calculation and tests of this show the anticipated qualitative behavior.
Levels of pentraxin-3 in gingival crevicular fluid and plasma in periodontal health and disease.
Pradeep, A R; Kathariya, Rahul; Raghavendra, N M; Sharma, Anuj
2011-05-01
Pentraxins are classic mediators of inflammation and markers of acute-phase reactions. Pentraxin-3 (PTX3) is the first-identified long pentraxin and is believed to be a true independent indicator of disease activity. Although a classic pentraxin, C-reactive protein, and its association with various systemic diseases is well documented in the periodontal literature, there is no data on PTX3 to our knowledge. Forty participants (20 males and 20 females; age range: 23 to 50 years) were involved in the study. Participants were divided into three groups based on gingival index, probing depth, and clinical attachment level: the healthy group (group 1; n = 10), gingivitis group (group 2; n = 15), and periodontitis group (group 3; n = 15). Gingival crevicular fluid (GCF) and plasma samples collected from each subject were quantified for PTX3 levels using an enzyme-linked immunosorbent assay. In tandem with the disease progression from healthy to gingivitis to periodontitis, the mean PTX3 concentrations increased in GCF and plasma. However, GCF values were higher than plasma values. It was found that PTX3 concentration was highest in group 3 and lowest in group 1. PTX3 concentrations also correlated positively with periodontal parameters. GCF and plasma PTX3 concentrations correlated positively in all groups. However, within the limits of the present study, the differences in plasma PTX3 levels were not found to be statistically significant. Hence, GCF PTX3 values were considered a marker of inflammatory activity in periodontal disease. However, PTX3 deserves further consideration as a therapeutic target. Additional large-scale studies should be carried out to confirm positive correlations.
Pooled population pharmacokinetic model of imipenem in plasma and the lung epithelial lining fluid.
van Hasselt, J G Coen; Rizk, Matthew L; Lala, Mallika; Chavez-Eng, Cynthia; Visser, Sandra A G; Kerbusch, Thomas; Danhof, Meindert; Rao, Gauri; van der Graaf, Piet H
2016-06-01
Several clinical trials have confirmed the therapeutic benefit of imipenem for treatment of lung infections. There is however no knowledge of the penetration of imipenem into the lung epithelial lining fluid (ELF), the site of action relevant for lung infections. Furthermore, although the plasma pharmacokinetics (PK) of imipenem has been widely studied, most studies have been based on selected patient groups. The aim of this analysis was to characterize imipenem plasma PK across populations and to quantify imipenem ELF penetration. A population model for imipenem plasma PK was developed using data obtained from healthy volunteers, elderly subjects and subjects with renal impairment, in order to identify predictors for inter-individual variability (IIV) of imipenem PK. Subsequently, a clinical study which measured plasma and ELF concentrations of imipenem was included in order to quantify lung penetration. A two compartmental model best described the plasma PK of imipenem. Creatinine clearance and body weight were included as subject characteristics predictive for IIV on clearance. Typical estimates for clearance, central and peripheral volume, and inter-compartmental clearance were 11.5 l h(-1) , 9.37 l, 6.41 l, 13.7 l h(-1) , respectively (relative standard error (RSE) imipenem into ELF was described using a time-independent penetration coefficient of 0.44 (RSE 14%). The identified lung penetration coefficient confirms the clinical relevance of imipenem for treatment of lung infections, while the population PK model provided insights into predictors of IIV for imipenem PK and may be of relevance to support dose optimization in various subject groups. © 2016 The British Pharmacological Society.
Software architecture for control and data acquisition of linear plasma generator Magnum-PSI
Groen, P.W.C.; Beveren, V. van; Broekema, A.; Busch, P.J.; Genuit, J.W.; Kaas, G.; Poelman, A.J.; Scholten, J.; Zeijlmans van Emmichoven, P.A.
2013-01-01
Highlights: ► An architecture based on a modular design. ► The design offers flexibility and extendability. ► The design covers the overall software architecture. ► It also covers its (sub)systems’ internal structure. -- Abstract: The FOM Institute DIFFER – Dutch Institute for Fundamental Energy Research has completed the construction phase of Magnum-PSI, a magnetized, steady-state, large area, high-flux linear plasma beam generator to study plasma surface interactions under ITER divertor conditions. Magnum-PSI consists of several hardware subsystems, and a variety of diagnostic systems. The COntrol, Data Acquisition and Communication (CODAC) system integrates these subsystems and provides a complete interface for the Magnum-PSI users. Integrating it all, from the lowest hardware level of sensors and actuators, via the level of networked PLCs and computer systems, up to functions and classes in programming languages, demands a sound and modular software architecture, which is extendable and scalable for future changes. This paper describes this architecture, and the modular design of the software subsystems. The design is implemented in the CODAC system at the level of services and subsystems (the overall software architecture), as well as internally in the software subsystems
Non linear dynamic of Langmuir and electromagnetic waves in space plasmas
Guede, Jose Ricardo Abalde
1995-11-01
The aim of this work is to study the nonlinear dynamics of Langmuir and electromagnetic waves in space plasmas. Firstly, the generalized Zakharov equations are derived which are used to study the hybrid parametric instability involving the generation of daughter Langmuir, electromagnetic and ion-acoustic waves induced by two counter-propagating Langmuir pump waves with different amplitudes based on a coupled dispersion relation. Secondly, starting from the generalized Zakharov equations the linear and nonlinear coupled mode theories of three-wave and four-wave parametric interactions are developed, respectively. In three-waves processes, a Langmuir wave decays into another Langmuir wave and an ion-acoustic wave (electrostatic parametric decay) or into an electromagnetic wave and an ion-acoustic wave (electromagnetic parametric decay). In four-wave (modulational) processes, the interaction involves two wave triplets: in the decay triplet a pump wave couples with a low-frequency wave to generate a Stokes wave, and in the fusion triplets: in the decay triplet a pump wave couples with a low-frequency wave to generate a Stokes wave, and in the fusion triplet the coupling of a pump wave with a low-frequency wave generate an anti-Stokes wave. These modulational processes are convective and resonant processes wherein the low-frequency modes are Eigenmodes of plasma and are known as the stimulated modulational processes. Four such processes are investigated in this thesis: two with Langmuir pump waves (electrostatic and hybrid stimulated modulation processes) and the other two with electromagnetic pump waves (stimulated modulation Brillouin scattering and electromagnetic stimulated modulation process). Applications of the theoretical results in space plasmas are discussed. In particular, it is shown that the electrostatic and electromagnetic parametric decay processes of Langmuir waves can model the generation and modulation of radio emissions and Langmuir waves in the
Mustafa, M.; Mushtaq, A.; Hayat, T.; Alsaedi, A.
2018-04-01
Mathematical model for Maxwell fluid flow in rotating frame induced by an isothermal stretching wall is explored numerically. Scale analysis based boundary layer approximations are applied to simplify the conservation relations which are later converted to similar forms via appropriate substitutions. A numerical approach is utilized to derive similarity solutions for broad range of Deborah number. The results predict that velocity distributions are inversely proportional to the stress relaxation time. This outcome is different from that observed for the elastic parameter of second grade fluid. Unlike non-rotating frame, the solution curves are oscillatory decaying functions of similarity variable. As angular velocity enlarges, temperature rises and significant drop in the heat transfer coefficient occurs. We note that the wall slope of temperature has an asymptotically decaying profile against the wall to ambient ratio parameter. From the qualitative view point, temperature ratio parameter and radiation parameter have similar effect on the thermal boundary layer. Furthermore, radiation parameter has a definite role in improving the cooling process of the stretching boundary. A comparative study of current numerical computations and those from the existing studies is also presented in a limiting case. To our knowledge, the phenomenon of non-linear radiation in rotating viscoelastic flow due to linearly stretched plate is just modeled here.
Becerik, Sema; Öztürk, Veli Özgen; Celec, Peter; Kamodyova, Natalia; Atilla, Gül; Emingil, Gülnur
2017-11-01
This study was aimed to evaluate the gingival crevicular fluid (GCF) and plasma transglutaminase-2 (TGM-2), total antioxidant capacity (TAC), total oxidant status (TOS), ferric reducing antioxidant power (FRAP) and thiobarbituric acid reactive substances (TBARS) in patients with chronic periodontal disease. Twenty patients with chronic periodontitis (CP), 20 patients with gingivitis and 20 healthy subjects were enrolled in the study. Clinical periodontal parameters including probing depth, clinical attachment level, plaque index and papillary bleeding index were recorded. GCF and plasma levels of TGM-2, TAC, TOS, TBARS and FRAP were analyzed. GCF TGM-2 was significantly lower in CP group than in gingivitis patients (P=0.006). GCF FRAP in CP and gingivitis groups was significantly lower than in healthy subjects (P0.05). GCF TGM-2 level was positively correlated with GCF TAC and negatively correlated with CAL. Decreased FRAP in GCF and plasma indicating lower antioxidant status of CP patients might suggest the role of oxidative stress in periodontitis. GCF TGM-2 data might suggest that TGM2 is associated with stabilization of the extracellular matrix and wound healing in periodontium rather than gingival inflammation. Copyright © 2017. Published by Elsevier Ltd.
Sarkar, Mahua; Grossman, Robert G; Toups, Elizabeth G; Chow, Diana S-L
2017-11-30
In the present study, a sensitive and robust LC-MS/MS method has been developed and validated for the quantification of riluzole in human plasma and cerebrospinal fluid (CSF) in clinical samples from patients with spinal cord injury (SCI). Riluzole and its labeled internal standard (IS) were isolated from plasma and CSF by liquid-liquid extraction using ethyl acetate. Riluzole (m/z 235→166) and IS (m/z 238→169) were detected by electrospray ionization (ESI) using multiple reaction monitoring (MRM) in a positive mode. The assay was linear in the concentration range of 0.5 (LLOQ, signal/noise ratio>10)-800ng/ml in plasma, and 1.0 (LLOQ)-800ng/ml in CSF samples. The intra- and inter-day accuracy in plasma were 94.2-110.0% and 97.8-102.0%, respectively, and those in CSF were 87.6-105.1% and 91.9-98.8%, respectively. The intra- and inter-day precision were 2.2-7.2% and 4.0-9.1%, respectively, in plasma, and 1.4-14.1% and 2.6-11.5%, respectively in CSF. Matrix effect was negligible from both matrices with signal percentages of 97.6-100.6% in plasma and 99.4-106.4% in CSF. The recoveries were >75% in plasma, >84% in CSF with low protein (53.9mg/dl), and >68% in CSF with high protein (348.2mg/dl). This method was successfully applied to quantify riluzole concentrations in plasma and CSF from patients with SCI. Copyright © 2017 Elsevier B.V. All rights reserved.
Aggarwal, Munish; Vij, Shivani; Kant, Niti
2015-01-01
The propagation of quadruple Gaussian laser beam in a plasma characterized by axial inhomogeneity and nonlinearity due to ponderomotive force in the paraxial ray approximation is investigated. An appropriate expression for the nonlinear dielectric constant has been developed in the presence of external magnetic field, with linear absorption and due to saturation effects for arbitrary large intensity. The effects of different types of plasma axial inhomogeneities on self-focusing of laser beam have been studied with the typical laser and plasma parameters. Self-focusing of quadruple Gaussian laser beam in the presence of externally applied magnetic field and saturating parameter is found significantly improved in the case of extraordinary mode. Our results reveal that initially converging beam shows oscillatory convergence whereas initially diverging beam shows oscillatory divergence. The beam is more focussed at lower intensity in both cases viz. extraordinary and ordinary mode. (paper)
Fast 2D Fluid-Analytical Simulation of IEDs and Plasma Uniformity in Multi-frequency CCPs
Kawamura, E.; Lieberman, M. A.; Graves, D. B.
2014-10-01
A fast 2D axisymmetric fluid-analytical model using the finite elements tool COMSOL is interfaced with a 1D particle-in-cell (PIC) code to study ion energy distributions (IEDs) in multi-frequency argon capacitively coupled plasmas (CCPs). A bulk fluid plasma model which solves the time-dependent plasma fluid equations is coupled with an analytical sheath model which solves for the sheath parameters. The fluid-analytical results are used as input to a PIC simulation of the sheath region of the discharge to obtain the IEDs at the wafer electrode. Each fluid-analytical-PIC simulation on a moderate 2.2 GHz CPU workstation with 8 GB of memory took about 15-20 minutes. The 2D multi-frequency fluid-analytical model was compared to 1D PIC simulations of a symmetric parallel plate discharge, showing good agreement. Fluid-analytical simulations of a 2/60/162 MHz argon CCP with a typical asymmetric reactor geometry were also conducted. The low 2 MHz frequency controlled the sheath width and voltage while the higher frequencies controlled the plasma production. A standing wave was observable at the highest frequency of 162 MHz. Adding 2 MHz power to a 60 MHz discharge or 162 MHz to a dual frequency 2 MHz/60 MHz discharge enhanced the plasma uniformity. This work was supported by the Department of Energy Office of Fusion Energy Science Contract DE-SC000193, and in part by gifts from Lam Research Corporation and Micron Corporation.
Nielsen, Tim; Brendel, Bernhard; Ziegler, Ronny; Beek, Michiel van; Uhlemann, Falk; Bontus, Claas; Koehler, Thomas
2009-01-01
Diffuse optical tomography (DOT) is a potential new imaging modality to detect or monitor breast lesions. Recently, Philips developed a new DOT system capable of transmission and fluorescence imaging, where the investigated breast is hanging freely into the measurement cup containing scattering fluid. We present a fast and robust image reconstruction algorithm that is used for the transmission measurements. The algorithm is based on the Rytov approximation. We show that this algorithm can be used over a wide range of tissue optical properties if the reconstruction is adapted to each patient. We use estimates of the breast shape and average tissue optical properties to initialize the reconstruction, which improves the image quality significantly. We demonstrate the capability of the measurement system and reconstruction to image breast lesions by clinical examples
Faried, Ahmad; Arief, Gusman; Arifin, Muhammad Z; Nataprawira, Heda M
2018-03-01
Tuberculous meningitis (TBM) is an endemic infectious disease in developing countries, and it can become a serious illness in children. Treatment of TBM is more difficult and prone to failure than treatment of pulmonary tuberculosis. TBM causes hydrocephalus, cerebral edema, increased intracranial pressure, global ischemia, and neurologic deficits, which disturb cellular metabolism and increase lactate levels. A reliable, widely available clinical indicator of TBM severity is needed. Successful treatment of TBM is assessed using the Glasgow Outcome Scale (GOS). This prospective cohort study included 34 patients with TBM and acute hydrocephalus who had undergone fluid diversions and were admitted to Dr. Hasan Sadikin Hospital in Bandung from 2014 to 2015. A portable machine for blood glucose measurement was used to measure lactate concentrations. Statistical significance was defined as P ≤ 0.05. Average levels of plasma and cerebrospinal fluid (CSF) lactate were 1.99 ± 0.70 mmol/L and 3.04 ± 1.05 mmol/L, respectively. A significantly higher level of lactate was observed in CSF compared with plasma. Preoperative plasma lactate was negatively correlated to GOS (r = -0.539; P = 0.013), and CSF lactate was negatively correlated to GOS (r = -0.412; P = 0.027). Average lactate levels in CSF (central) were higher than plasma (peripheral) levels. GOS scale of patients decreased with increased plasma and CSF lactate levels. Examination of plasma and CSF lactate levels should be included in routine examinations to determine extent of cellular damage and GOS score in patients with TBM and acute hydrocephalus who have undergone fluid diversions. Copyright © 2017 Elsevier Inc. All rights reserved.
Messenger, K M; Wofford, J A; Papich, M G
2016-02-01
Measurement of unbound drug concentrations at their sites of action is necessary for accurate PK/PD modeling. The objective of this study was to determine the unbound concentration of carprofen in canine interstitial fluid (ISF) using in vivo ultrafiltration and to compare pharmacokinetic parameters of free carprofen concentrations between inflamed and control tissue sites. We hypothesized that active concentrations of carprofen would exhibit different dispositions in ISF between inflamed vs. normal tissues. Bilateral ultrafiltration probes were placed subcutaneously in six healthy Beagle dogs 12 h prior to induction of inflammation. Two milliliters of either 2% carrageenan or saline control was injected subcutaneously at each probe site, 12 h prior to intravenous carprofen (4 mg/kg) administration. Plasma and ISF samples were collected at regular intervals for 72 h, and carprofen concentrations were determined using HPLC. Prostaglandin E2 (PGE2 ) concentrations were quantified in ISF using ELISA. Unbound carprofen concentrations were higher in ISF compared with predicted unbound plasma drug concentrations. Concentrations were not significantly higher in inflamed ISF compared with control ISF. Compartmental modeling was used to generate pharmacokinetic parameter estimates, which were not significantly different between sites. Terminal half-life (T½) was longer in the ISF compared with plasma. PGE2 in ISF decreased following administration of carprofen. In vivo ultrafiltration is a reliable method to determine unbound carprofen in ISF, and that disposition of unbound drug into tissue is much higher than predicted from unbound drug concentration in plasma. However, concentrations and pharmacokinetic parameter estimates are not significantly different in inflamed vs. un-inflamed tissues. © 2015 John Wiley & Sons Ltd.
Misguich, J.H.; Balescu, R.
1981-02-01
Three different time regimes are presented for relative spatial diffusion of charged particles in fluctuating electric fields, which behave like tau 3 , exp (tau) and tau 3 , respectively. The first regime, corresponding to a quasi-linear description of the trajectories, is analogous to the one observed in fluid turbulence and is valid in the limit of a small amplitude turbulent spectrum, or for not too small initial separation of the particles. The third regime, appearing for long times, describes the diffusion of independent particles at very large separations. Its existence is ensured by the nonlinear renormalization of the propagators. The second, intermediate, regime appears in a stochastic treatment of the renormalization effect for particles with a very small spatial and velocity difference, and describes Dupree's clumps diffusion. The appearance of the corresponding regime is similar to that of the Suzuki scaling regime of non-linear Langevin equations. It is also shown that the clumps have a behaviour similar to an intrinsic stochasticity, but which is of extrinsic nature. Similar failure of the quasi-linear approximation for spacific velocity domains has been previously studied and solved for classical Landau collisions, as well as for pitch angle diffusion where renormalization effects have been proved also to be important
Qamar, Wajhul; Al-Ghadeer, Abdul Rahman; Ali, Raisuddin; Abuelizz, Hatem A
2017-08-01
The main objective was to determine the elemental profile of the lung lining fluid of rats which are used as model animals in various experiments. Lung lining fluid elemental constitution obtained after bronchoalveolar lavage fluid (BALF) was analyzed by inductively coupled plasma mass spectrometry (ICP-MS) to determine the biological trace elements along with calcium and magnesium. BALF was collected from healthy rats using a tracheal cannula. However, cells in BALF were counted to monitor any underlying inflammatory lung condition. Cell free BALF samples were processed and analyzed for the elements including magnesium (Mg), calcium (Ca), chromium (Cr), manganese (Mn), iron (Fe), nickel (Ni), copper (Cu), zinc (Zn), selenium (Se), bromine (Br), and iodine (I). In view of this, calcium concentration was the highest (6318.08 ± 3094.3 μg/L) and copper concentration was the lowest (0.89 ± 0.21 μg/L). The detected elements, from high to low concentration, include Ca > Mg > Fe > Br > I > Cr > Ni > Zn > Mn > Se > Cu. Pearson's correlation analysis revealed no significant correlation between cell count and concentration of any of the element detected in BALF. Correlation analysis also revealed significant positive correlation among Fe, I, Cr, Ni, and Mn. Ca was found to be correlated negatively with Cu and positively with Se. Br and Mg found to be positively correlated with each other. Zn remained the only element that was not found to be correlated with any of the elements in the rat BALF.
Discretization of the Joule heating term for plasma discharge fluid models in unstructured meshes
Deconinck, T.; Mahadevan, S.; Raja, L.L.
2009-01-01
The fluid (continuum) approach is commonly used for simulation of plasma phenomena in electrical discharges at moderate to high pressures (>10's mTorr). The description comprises governing equations for charged and neutral species transport and energy equations for electrons and the heavy species, coupled to equations for the electromagnetic fields. The coupling of energy from the electrostatic field to the plasma species is modeled by the Joule heating term which appears in the electron and heavy species (ion) energy equations. Proper numerical discretization of this term is necessary for accurate description of discharge energetics; however, discretization of this term poses a special problem in the case of unstructured meshes owing to the arbitrary orientation of the faces enclosing each cell. We propose a method for the numerical discretization of the Joule heating term using a cell-centered finite volume approach on unstructured meshes with closed convex cells. The Joule heating term is computed by evaluating both the electric field and the species flux at the cell center. The dot product of these two vector quantities is computed to obtain the Joule heating source term. We compare two methods to evaluate the species flux at the cell center. One is based on reconstructing the fluxes at the cell centers from the fluxes at the face centers. The other recomputes the flux at the cell center using the common drift-diffusion approximation. The reconstructed flux scheme is the most stable method and yields reasonably accurate results on coarse meshes.
Henriksen, Jens Henrik Sahl; Ring-Larsen, H; Lassen, N A
1983-01-01
was on the average 0.22 of that of plasma and directly correlated to the plasma concentration (rlin = 0.68, P less than 0.01). The hydrostatic pressure difference across the splanchnic microvasculature (assessed as wedged hepatic vein minus inferior vena caval pressure) was directly correlated to the effective...... (plasma minus ascitic fluid) oncotic pressure (rlin = 0.74, P less than 0.001) but significantly higher than that (P less than 0.005), indicating a 'non-equilibrium' in the splanchnic Starling forces. The results point to a multivariate genesis and perpetuation of cirrhotic ascites as laid down...
Low temperature diamond growth by linear antenna plasma CVD over large area
Izak, Tibor; Babchenko, Oleg; Potocky, Stepan; Kromka, Alexander; Varga, Marian
2012-01-01
Recently, there is a great effort to increase the deposition area and decrease the process temperature for diamond growth which will enlarge its applications including use of temperature sensitive substrates. In this work, we report on the large area (20 x 30 cm 2 ) and low temperature (250 C) polycrystalline diamond growth by pulsed linear antenna microwave plasma system. The influence of substrate temperature varied from 250 to 680 C, as controlled by the table heater and/or by microwave power, is studied. It was found that the growth rate, film morphology and diamond to non-diamond phases (sp 3 /sp 2 carbon bonds) are influenced by the growth temperature, as confirmed by SEM and Raman measurements. The surface chemistry and growth processes were studied in terms of activation energies (E a ) calculated from Arrhenius plots. The activation energies of growth processes were very low (1.7 and 7.8 kcal mol -1 ) indicating an energetically favourable growth process from the CO 2 -CH 4 -H 2 gas mixture. In addition, from activation energies two different growth regimes were observed at low and high temperatures, indicating different growth mechanism. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Shukla, P. K.; Eliasson, B.; Akbari-Moghanjoughi, M.
2013-03-01
In a recent paper, Bonitz, Pehlke, and Schoof [Phys. Rev. E10.1103/PhysRevE.87.033105 87, 033105 (2013)], hereafter referred to as BPS, have raised some points against the Shukla-Eliasson attractive potential [P. K. Shukla and B. Eliasson, Phys. Rev. Lett.0031-900710.1103/PhysRevLett.108.165007 108, 165007 (2012); P. K. Shukla and B. Eliasson, Phys. Rev. Lett.0031-900710.1103/PhysRevLett.108.219902 108, 219902(E) (2012); P. K. Shukla and B. Eliasson, Phys. Rev. Lett.10.1103/PhysRevLett.109.019901 109, 019901(E) (2012)], hereafter referred to as SEAP, around a stationary test charge in a quantum plasma. Our objective here is to discuss the insufficiency of the BPS reasoning concerning the applicability of the linearized quantum hydrodynamic theory, as well as to point out the shortcomings in BPS’s arguments and to suggest how to salvage BPS’s density functional theory and simulations, which have failed to produce results that correctly match with that of Shukla and Eliasson.
Unified theory of damping of linear surface Alfven waves in inhomogeneous incompressible plasmas
Ruderman, M.S.; Goossens, M.
1996-01-01
The viscous damping of surface Alfven waves in a non-uniform plasma is studied in the context of linear and incompressible MHD. It is shown that damping due to resonant absorption and damping on a true discontinuity are two limiting cases of the continuous variation of the damping rate with respect to the dimensionless number Rg = Δλ 2 Re, where Δ is the relative variation of the local Alfven velocity, λ is the ratio of the thickness of the inhomogeneous layer to the wavelength, and Re is the viscous Reynolds number. The analysis is restricted to waves with wavelengths that are long in comparison with the extent of the non-uniform layer (λ '' >'' 1) values of Rg. For very small values of Rg, the damping rate agrees with that found for a true discontinuity, while for very large values of Rg, it agrees with the damping rate due to resonant absorption. The dispersion relation is subsequently studied numerically over a wide range of values of Rg, revealing a continuous but non-monotonic variation of the damping rate with respect to Rg. (Author)
Cesario, Roberto; Cardinali, Alessandro; Castaldo, Carmine; Amicucci, Luca; Ceccuzzi, Silvio; Galli, Alessandro; Napoli, Francesco; Panaccione, Luigi; Santini, Franco; Schettini, Giuseppe; Tuccillo, Angelo Antonio
2017-10-01
The main research on the energy from thermonuclear fusion uses deuterium plasmas magnetically trapped in toroidal devices. To suppress the turbulent eddies that impair thermal insulation and pressure tight of the plasma, current drive (CD) is necessary, but tools envisaged so far are unable accomplishing this task while efficiently and flexibly matching the natural current profiles self-generated at large radii of the plasma column [1-5]. The lower hybrid current drive (LHCD) [6] can satisfy this important need of a reactor [1], but the LHCD system has been unexpectedly mothballed on JET. The problematic extrapolation of the LHCD tool at reactor graded high values of, respectively, density and temperatures of plasma has been now solved. The high density problem is solved by the FTU (Frascati Tokamak Upgrade) method [7], and solution of the high temperature one is presented here. Model results based on quasi-linear (QL) theory evidence the capability, w.r.t linear theory, of suitable operating parameters of reducing the wave damping in hot reactor plasmas. Namely, using higher RF power densities [8], or a narrower antenna power spectrum in refractive index [9,10], the obstacle for LHCD represented by too high temperature of reactor plasmas should be overcome. The former method cannot be used for routinely, safe antenna operations, Thus, only the latter key is really exploitable in a reactor. The proposed solutions are ultimately necessary for viability of an economic reactor.
Tanaka, H.; Ohno, N.; Tsuji, Y.; Kajita, S.
2010-01-01
We have analyzed the 2D convective motion of coherent structures, which is associated with plasma blobs, under attached and detached plasma conditions of a linear divertor simulator, NAGDIS-II. Data analysis of probes and a fast-imaging camera by spatio-temporal correlation with three decomposition and proper orthogonal decomposition (POD) was carried out to determine the basic properties of coherent structures detached from a bulk plasma column. Under the attached plasma condition, the spatio-temporal correlation with three decomposition based on the probe measurement showed that two types of coherent structures with different sizes detached from the bulk plasma and the azimuthally localized structure radially propagated faster than the larger structure. Under the detached plasma condition, movies taken by the fast-imaging camera clearly showed the dynamics of a 2D spiral structure at peripheral regions of the bulk plasma; this dynamics caused the broadening of the plasma profile. The POD method was used for the data processing of the movies to obtain low-dimensional mode shapes. It was found that the m=1 and m=2 ring-shaped coherent structures were dominant. Comparison between the POD analysis of both the movie and the probe data suggested that the coherent structure could be detached from the bulk plasma mainly associated with the m=2 fluctuation. This phenomena could play an important role in the reduction of the particle and heat flux as well as the plasma recombination processes in plasma detachment (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)
Frederiksen, Hanne; Taxvig, Camilla; Hass, Ulla
2008-01-01
to obtain more knowledge about the distribution of ethyl paraben and butyl paraben in pregnant rats and pups after perinatal exposure, the presented study was designed. The data show response and distribution of ethyl paraben and butyl paraben in maternal rat plasma, pools of amniotic fluids, placenta......, whole-body fetuses, and in fetal liver after dosing of dams with 100, 200, and 400 mg/kg body weight (bw)/day from gestational day 7 to 21. After cesarean section of dams, the fluids and tissues were collected, deconjugated, and purified by solid-phase extraction, and ethyl paraben and butyl paraben...... were analyzed by liquid chromatography-tandem mass spectrometry. Markedly higher levels of ethyl paraben compared to butyl paraben were found in all fluids and tissues. Both ethyl paraben and butyl paraben in maternal plasma, livers, and whole-body tissues from fetus seemed to be saturated after dosing...
Hopkins Stephen J
2012-11-01
Full Text Available Abstract Background Cytokines and cytokine receptor concentrations increase in plasma and cerebrospinal fluid (CSF of patients following subarachnoid haemorrhage (SAH. The relationship between plasma and CSF cytokines, and factors affecting this, are not clear. Methods To help define the relationship, paired plasma and cerebrospinal fluid (CSF samples were collected from patients subject to ventriculostomy. Concentrations of key inflammatory cytokines, interleukin (IL-1ß, IL-1 receptor antagonist (IL-1Ra, IL-1 receptor 2, IL-6, IL-8, IL-10, tumour necrosis factor (TNF-α, and TNF receptors (TNF-R 1 and 2 were determined by immunoassay of CSF and plasma from 21 patients, where samples were available at three or more time points. Results Plasma concentrations of IL-1ß, IL-1Ra, IL-10, TNF-α and TNF-R1 were similar to those in CSF. Plasma TNF-R2 and IL-1R2 concentrations were higher than in CSF. Concentrations of IL-8 and IL-6 in CSF were approximately10 to 1,000-fold higher than in plasma. There was a weak correlation between CSF and plasma IL-8 concentrations (r = 0.26, but no correlation for IL-6. Differences between the central and peripheral pattern of IL-6 were associated with episodes of ventriculostomy-related infection (VRI. A VRI was associated with CSF IL-6 >10,000 pg/mL (P = 0.0002, although peripheral infection was not significantly associated with plasma IL-6. Conclusions These data suggest that plasma cytokine concentrations cannot be used to identify relative changes in the CSF, but that measurement of CSF IL-6 could provide a useful marker of VRI.
Knych, H K; Harrison, L M; Casbeer, H C; McKemie, D S
2014-04-01
Methylprednisolone acetate (MPA) is commonly administered to performance horses, and therefore, establishing appropriate withdrawal times prior to performance is critical. The objectives of this study were to describe the plasma pharmacokinetics of MPA and time-related urine and synovial fluid concentrations following intra-articular administration to sixteen racing fit adult Thoroughbred horses. Horses received a single intra-articular administration of MPA (100 mg). Blood, urine, and synovial fluid samples were collected prior to and at various times up to 77 days postdrug administration and analyzed using tandem liquid chromatography-mass spectrometry (LC-MS/MS). Maximum measured plasma MPA concentrations were 6.06 ± 1.57 at 0.271 days (6.5 h; range: 5.0-7.92 h) and 6.27 ± 1.29 ng/mL at 0.276 days (6.6 h; range: 4.03-12.0 h) for horses that had synovial fluid collected (group 1) and those that did not (group 2), respectively. The plasma terminal half-life was 1.33 ± 0.80 and 0.843 ± 0.414 days for groups 1 and 2, respectively. MPA was undetectable by day 6.25 ± 2.12 (group 1) and 4.81 ± 2.56 (group 2) in plasma and day 17 (group 1) and 14 (group 2) in urine. MPA concentrations in synovial fluid remained above the limit of detection (LOD) for up to 77 days following intra-articular administration, suggesting that plasma and urine concentrations are not a good indicator of synovial fluid concentrations. © 2013 John Wiley & Sons Ltd.
Wilk, R.; Syc, B.; Bajor, G.; Kluczewska, E.
2011-01-01
Currently, a few imaging methods are used in CNS diagnostics: computed tomography - CT, magnetic resonance imaging - MRI, and ultrasonography - USG. The ventricular system changes its dimensions with child's development. Linear indices commonly used in the diagnostics of hydrocephalus do not consider developmental changes of the intracranial fluid spaces. The aim of our work was to identify reference values for selected linear indices in specific age groups. Material/Methods: The material included 507 CT examinations of the head in children of different age and both sexes. There were 381 CT examinations considered as normal and they were used to establish the reference values. They were compared with 126 CTs from the observational zone (3-10 percentile and 90-97 percentile). The children were divided into 7 following age groups: 0-12 months, > 12-36 months, > 3-6 years, > 6-9 years, > 9-12 years, > 12-15 years, > 15-18 years. For every group, the 10 th , 25 th , 50 th , 75 th and 90 th percentile was calculated. The range between the 10 th and the 90 th percentile was described as a norm. Results: Reference values for particular indices: Huckman Number from 3.3 to 5.0 cm with correlation coefficient according to age equal to 0.34; Evans' Index from 0.218 to 0.312 with correlation coefficient of -0.12; Bifrontal Index from 0.265 to 0.380 with correlation coefficient of 0.18; Bicaudate / Frontal Index from 0.212 to 0.524 with correlation coefficient of -0,33; Bicaudate Index from 0.059 to 0.152 with correlation coefficient of -0.26; Bicaudate / Temporal Index from 0.051 to 0.138 with correlation coefficient of 0.32; Schiersmann's Index from 3.545 to 6.038 with correlation coefficient of 0.42. Conclusions: The intracerebral CSF spaces increased in a non-uniform manner with age. All indices established on the basis of linear parameters were relatively higher in younger children than in the older ones. In proportion to the cranial size, the intracranial fluid spaces
Quasi-linear heating and acceleration in bi-Maxwellian plasmas
Hellinger, Petr; Passot, T.; Sulem, P. L.; Trávníček, Pavel M.
2013-01-01
Roč. 20, č. 12 (2013), 122306/1-122306/6 ISSN 1070-664X Institutional support: RVO:68378289 Keywords : plasma electromagnetic waves * plasma nonlinear phenomena * diffusion Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 2.249, year: 2013 http://scitation.aip.org/content/aip/journal/pop/20/12/10.1063/1.4846955
Study of wave-particle interaction from the linear regime to dynamical chaos in a magnetized plasma
Fasoli, A.
1993-10-01
Deterministic chaos generated by the interaction between charged particles and electrostatic plasma waves has been observed in a linear magnetized plasma. The target plasma is created by a barium Q-source, guaranteeing low fluctuation levels and a high degree of uniformity over an extended plasma volume. Characteristics of the background plasma are investigated by a variety of diagnostic techniques, including laser induced fluorescence (LIF) and optical tagging (OT). Particular tagging schemes and specific theoretical approaches to data interpretation (both for LIF and OT) have been developed during this work. As part of these background plasma studies, special attention has been devoted to an investigation of test-ion cross-field transport under different conditions. Test-ions are created and followed in their motion across the magnetic field lines via spin state tagging. In the unperturbed plasma this motion is found to be a diffusive process, supported by classical mechanisms, even in the presence of relatively high pressures of non-reactive neutral gases injected into the plasma volume. Electrostatic waves are excited using a ring antenna structure encircling the plasma column and electrically isolated from it. This system has been chosen on the basis of a comparative analysis of different ion wave launching methods, including the use of grids, inductive coils coupled electromagnetically to the plasma and modulated high frequency electron waves. Two modes propagating parallel to the magnetic field, one of which has two perpendicular components (ion Bernstein and ion acoustic-like waves), characterize the spectrum excited by the electrostatic ring antenna for a single frequency, f, chosen in the range f ci ci . (author) figs., tabs., 134 refs
A non-linear theory for the bubble regime of plasma wake fields in tailored plasma channels
Thomas, Johannes
2016-01-01
We introduce a first full analytical bubble and blow-out model for a radially inhomogeneous plasma in a quasi-static approximation. For both cases we calculate the accelerating and the focusing fields. In our model we also assume a thin electron layer that surrounds the wake field and calculate the field configuration within. Our theory holds for arbitrary radial density profiles and reduces to known models in the limit of a homogeneous plasma. From a previous study of hollow plasma channels with smooth boundaries for laser-driven electron acceleration in the bubble regime we know that pancake-like laser pulses lead to highest electron energies [Pukhov et al, PRL 113, 245003 (2014)]. As it was shown, the bubble fields can be adjusted to balance the laser depletion and dephasing lengths by varying the plasma density profile inside a deep channel. Now we show why the radial fields in the vacuum part of a channel become defocussing.
Potential formation in the plasma confinement region of a radio-frequency plugged linear device
Fujita, Hideki; Kumazawa, Ryuhei; Howald, A.M.; Okamura, Shoichi; Sato, Teruyuki; Adati, Keizo; Garner, H.R.; Nishimura, Kiyohiko.
1987-08-01
Plasma potential formation in an open-ended plasma confinement system with RF plugging (the RFC-XX-M device) is investigated. The plasma potential in the central confinement region is measured with a heavy ion beam probe system and potentials at the RF plug section are measured with multi-grid energy analyzers. The measured plasma potential is compared with that deduced from the generalized Pastukhov formula. Results show that the plasma potential develops as an ambipolar potential to equate ion and electron end losses. During RF plugging, electrons are heated by Landau damping, while ions are not heated since adiabatic conditions apply during ion plugging in this experiment. (author)
Martin, Pablo; Castro, Enrique; Puerta, Julio
2009-01-01
Non-linear plasma diffusion effects due to hole currents in tokamaks is analyzed in this work. Since the recent discovery of hole currents in tokamaks, this matter has become very important in confinement and instabilities in tokamaks plasmas. The analysis here presented includes non-linear flows as well as hole currents. In the case of low vorticity plasmas our treatment is performed using MHD equations, an it is more suitable for plasmas with very low levels of turbulence, as in the H-mode. The present treatment follows the lines of previous works, and some of the equations and results look like those obtained on these papers. However, the form of the family of the magnetic surfaces is very different to previous treatment, since the hole current modifies those families in a very important way. Elliptic plasmas with triangularity are considered. Pfirsch-Schlueter type currents are obtained for these generalized cases. Diffusion with and without holes are calculated and compared for several values of ellipticity and triangularity. Negative and positive triangularities are considered. In most of the calculations triangularity improves confinement, but the results are different for the positive than for the negative case.
Generalized fluid equations for parallel transport in collisional to weakly collisional plasmas
Zawaideh, E.; Najmabadi, F.; Conn, R.W.
1986-01-01
A new set of two-fluid equations that are valid from collisional to weakly collisional limits is derived. Starting from gyrokinetic equations in flux coordinates with no zero-order drifts, a set of moment equations describing plasma transport along the field lines of a space- and time-dependent magnetic field is derived. No restriction on the anisotropy of the ion distribution function is imposed. In the highly collisional limit, these equations reduce to those of Braginskii, while in the weakly collisional limit they are similar to the double adiabatic or Chew, Goldberger, and Low (CGL) equations [Proc. R. Soc. London, Ser. A 236, 112 (1956)]. The new set of equations also exhibits a physical singularity at the sound speed. This singularity is used to derive and compute the sound speed. Numerical examples comparing these equations with conventional transport equations show that in the limit where the ratio of the mean free path lambda to the scale length of the magnetic field gradient L/sub B/ approaches zero, there is no significant difference between the solution of the new and conventional transport equations. However, conventional fluid equations, ordinarily expected to be correct to the order (lambda/L/sub B/) 2 , are found to have errors of order (lambda/L/sub u/) 2 = (lambda/L/sub B/) 2 /(1-M 2 ) 2 , where L/sub u/ is the scale length of the flow velocity gradient and M is the Mach number. As such, the conventional equations may contain large errors near the sound speed (Mroughly-equal1)
Resistance exercise-induced fluid shifts: change in active muscle size and plasma volume
Ploutz-Snyder, L. L.; Convertino, V. A.; Dudley, G. A.
1995-01-01
The purpose of this study was to test the hypothesis that the reduction in plasma volume (PV) induced by resistance exercise reflects fluid loss to the extravascular space and subsequently selective increase in cross-sectional area (CSA) of active but not inactive skeletal muscle. We compared changes in active and inactive muscle CSA and PV after barbell squat exercise. Magnetic resonance imaging (MRI) was used to quantify muscle involvement in exercise and to determine CSA of muscle groups or individual muscles [vasti (VS), adductor (Add), hamstring (Ham), and rectus femoris (RF)]. Muscle involvement in exercise was determined using exercise-induced contrast shift in spin-spin relaxation time (T2)-weighted MR images immediately postexercise. Alterations in muscle size were based on the mean CSA of individual slices. Hematocrit, hemoglobin, and Evans blue dye were used to estimate changes in PV. Muscle CSA and PV data were obtained preexercise and immediately postexercise and 15 and 45 min thereafter. A hierarchy of muscle involvement in exercise was found such that VS > Add > Ham > RF, with the Ham and RF showing essentially no involvement. CSA of the VS and Add muscle groups were increased 10 and 5%, respectively, immediately after exercise in each thigh with no changes in Ham and RF CSA. PV was decreased 22% immediately following exercise. The absolute loss of PV was correlated (r2 = 0.75) with absolute increase in muscle CSA immediately postexercise, supporting the notion that increased muscle size after resistance exercise reflects primarily fluid movement from the vascular space into active but not inactive muscle.
Emadi, E.; Zahed, H. [Physics Department, Faculty of Science, Sahand University of Technology, 51335–1996 Tabriz (Iran, Islamic Republic of)
2016-08-15
The behavior of linear and nonlinear dust ion acoustic (DIA) solitary waves in an unmagnetized quantum dusty plasma, including inertialess electrons and positrons, ions, and mobile negative dust grains, are studied. Reductive perturbation and Sagdeev pseudopotential methods are employed for small and large amplitude DIA solitary waves, respectively. A minimum value of the Mach number obtained for the existence of solitary waves using the analytical expression of the Sagdeev potential. It is observed that the variation on the values of the plasma parameters such as different values of Mach number M, ion to electron Fermi temperature ratio σ, and quantum diffraction parameter H can lead to the creation of compressive solitary waves.
Linear MHD stability analysis of post-disruption plasmas in ITER
Aleynikova, K., E-mail: ksenia.aleynikova@gmail.com [EURATOM Association, Max-Planck-Institut für Plasmaphysik (Germany); Huijsmans, G. T. A. [ITER Organization (France); Aleynikov, P. [EURATOM Association, Max-Planck-Institut für Plasmaphysik (Germany)
2016-05-15
Most of the plasma current can be replaced by a runaway electron (RE) current during plasma disruptions in ITER. In this case the post-disruption plasma current profile is likely to be more peaked than the pre-disruption profile. The MHD activity of such plasma will affect the runaway electron generation and confinement and the dynamics of the plasma position evolution (Vertical Displacement Event), limiting the timeframe for runaway electrons and disruption mitigation. In the present paper, we evaluate the influence of the possible RE seed current parameters on the onset of the MHD instabilities. By varying the RE seed current profile, we search for subsequent plasma evolutions with the highest and the lowest MHD activity. This information can be applied to a development of desirable ITER disruption scenario.
Dahl, Viktor; Gisslen, Magnus; Hagberg, Lars; Peterson, Julia; Shao, Wei; Spudich, Serena; Price, Richard W; Palmer, Sarah
2014-05-15
We sequenced the genome of human immunodeficiency virus type 1 (HIV-1) recovered from 70 cerebrospinal fluid (CSF) specimens and 29 plasma samples and corresponding samples obtained before treatment initiation from 17 subjects receiving suppressive therapy. More CSF sequences than plasma sequences were hypermutants. We determined CSF sequences and plasma sequences in specimens obtained from 2 subjects after treatment initiation. In one subject, we found genetically distinct CSF and plasma sequences, indicating that they came from HIV-1 from 2 different compartments, one potentially the central nervous system, during suppressive therapy. In addition, there was little evidence of viral evolution in the CSF during therapy, suggesting that continuous virus replication is not the major cause of viral persistence in the central nervous system.
Lee, Dayong; Vandrey, Ryan; Milman, Garry; Bergamaschi, Mateus; Mendu, Damodara R; Murray, Jeannie A; Barnes, Allan J; Huestis, Marilyn A
2013-09-01
Oral fluid (OF) is a valuable biological alternative for clinical and forensic drug testing. Evaluating OF to plasma (OF/P) cannabinoid ratios provides important pharmacokinetic data on the disposition of drug and factors influencing partition between matrices. Eleven chronic cannabis smokers resided on a closed research unit for 51 days. There were four 5-day sessions of 0, 30, 60, and 120 mg oral ∆(9)-tetrahydrocannabinol (THC)/day followed by a five-puff smoked cannabis challenge on Day 5. Each session was separated by 9 days ad libitum cannabis smoking. OF and plasma specimens were analyzed for THC and metabolites. During ad libitum smoking, OF/P THC ratios were high (median, 6.1; range, 0.2-348.5) within 1 h after last smoking, decreasing to 0.1-20.7 (median, 2.1) by 13.0-17.1 h. OF/P THC ratios also decreased during 5-days oral THC dosing, and after the smoked cannabis challenge, median OF/P THC ratios decreased from 1.4 to 5.5 (0.04-245.6) at 0.25 h to 0.12 to 0.17 (0.04-5.1) at 10.5 h post-smoking. In other studies, longer exposure to more potent cannabis smoke and oromucosal cannabis spray was associated with increased OF/P THC peak ratios. Median OF/P 11-nor-9-carboxy-THC (THCCOOH) ratios were 0.3-2.5 (range, 0.1-14.7) ng/μg, much more consistent in various dosing conditions over time. OF/P THC, but not THCCOOH, ratios were significantly influenced by oral cavity contamination after smoking or oromucosal spray of cannabinoid products, followed by time-dependent decreases. Establishing relationships between OF and plasma cannabinoid concentrations is essential for making inferences of impairment or other clinical outcomes from OF concentrations.
Desrosiers, Nathalie A; Barnes, Allan J; Hartman, Rebecca L; Scheidweiler, Karl B; Kolbrich-Spargo, Erin A; Gorelick, David A; Goodwin, Robert S; Huestis, Marilyn A
2013-05-01
Oral fluid (OF) offers a noninvasive sample collection for drug testing. However, 3,4-methylenedioxymethamphetamine (MDMA, ecstasy) in OF has not been adequately characterized in comparison to plasma. We administered oral low-dose (1.0 mg/kg) and high-dose (1.6 mg/kg) MDMA to 26 participants and collected simultaneous OF and plasma specimens for up to 143 h after dosing. We compared OF/plasma (OF/P) ratios, time of initial detection (t first), maximal concentrations (C max), time of peak concentrations (t max), time of last detection (t last), clearance, and 3,4-methylenedioxyamphetamine (MDA)-to-MDMA ratios over time. For OF MDMA and MDA, C max was higher, t last was later, and clearance was slower compared to plasma. For OF MDA only, t first was later compared to plasma. Median (range) OF/P ratios were 5.6 (0.1-52.3) for MDMA and 3.7 (0.7-24.3) for MDA. OF and plasma concentrations were weakly but significantly correlated (MDMA: R(2) = 0.438, MDA: R(2) = 0.197, p MDMA low = 5.2 (0.1-40.4), high = 6.0 (0.4-52.3, p MDMA ratios in plasma were higher than those in OF (p MDMA ratios significantly increased over time in OF and plasma. The MDMA and MDA concentrations were higher in OF than in plasma. OF and plasma concentrations were correlated, but large inter-subject variability precludes the estimation of plasma concentrations from OF.
Two-fluid electromagnetic simulations of plasma-jet acceleration with detailed equation-of-state
Thoma, C.; Welch, D. R.; Clark, R. E.; Bruner, N.; MacFarlane, J. J.; Golovkin, I. E.
2011-01-01
We describe a new particle-based two-fluid fully electromagnetic algorithm suitable for modeling high density (n i ∼ 10 17 cm -3 ) and high Mach number laboratory plasma jets. In this parameter regime, traditional particle-in-cell (PIC) techniques are challenging due to electron timescale and lengthscale constraints. In this new approach, an implicit field solve allows the use of large timesteps while an Eulerian particle remap procedure allows simulations to be run with very few particles per cell. Hall physics and charge separation effects are included self-consistently. A detailed equation of state (EOS) model is used to evolve the ion charge state and introduce non-ideal gas behavior. Electron cooling due to radiation emission is included in the model as well. We demonstrate the use of these new algorithms in 1D and 2D Cartesian simulations of railgun (parallel plate) jet accelerators using He and Ar gases. The inclusion of EOS and radiation physics reduces the electron temperature, resulting in higher calculated jet Mach numbers in the simulations. We also introduce a surface physics model for jet accelerators in which a frictional drag along the walls leads to axial spreading of the emerging jet. The simulations demonstrate that high Mach number jets can be produced by railgun accelerators for a variety of applications, including high energy density physics experiments.
Two-fluid electromagnetic simulations of plasma-jet acceleration with detailed equation-of-state
Thoma, C.; Welch, D. R.; Clark, R. E.; Bruner, N. [Voss Scientific, LLC, Albuquerque, New Mexico 87108 (United States); MacFarlane, J. J.; Golovkin, I. E. [Prism Computational Sciences, Inc., Madison, Wisconsin 53711 (United States)
2011-10-15
We describe a new particle-based two-fluid fully electromagnetic algorithm suitable for modeling high density (n{sub i} {approx} 10{sup 17} cm{sup -3}) and high Mach number laboratory plasma jets. In this parameter regime, traditional particle-in-cell (PIC) techniques are challenging due to electron timescale and lengthscale constraints. In this new approach, an implicit field solve allows the use of large timesteps while an Eulerian particle remap procedure allows simulations to be run with very few particles per cell. Hall physics and charge separation effects are included self-consistently. A detailed equation of state (EOS) model is used to evolve the ion charge state and introduce non-ideal gas behavior. Electron cooling due to radiation emission is included in the model as well. We demonstrate the use of these new algorithms in 1D and 2D Cartesian simulations of railgun (parallel plate) jet accelerators using He and Ar gases. The inclusion of EOS and radiation physics reduces the electron temperature, resulting in higher calculated jet Mach numbers in the simulations. We also introduce a surface physics model for jet accelerators in which a frictional drag along the walls leads to axial spreading of the emerging jet. The simulations demonstrate that high Mach number jets can be produced by railgun accelerators for a variety of applications, including high energy density physics experiments.
Kimiskidis, Vasilios; Spanakis, Marios; Niopas, Ioannis; Kazis, Dimitrios; Gabrieli, Chrysi; Kanaze, Feras Imad; Divanoglou, Daniil
2007-01-17
An isocratic reversed-phase HPLC-UV procedure for the determination of oxcarbazepine and its main metabolites 10-hydroxy-10,11-dihydrocarbamazepine and 10,11-dihydroxy-trans-10,11-dihydrocarbamazepine in human plasma and cerebrospinal fluid has been developed and validated. After addition of bromazepam as internal standard, the analytes were isolated from plasma and cerebrospinal fluid by liquid-liquid extraction. Separation was achieved on a X-TERRA C18 column using a mobile phase composed of 20 mM KH(2)PO(4), acetonitrile, and n-octylamine (76:24:0.05, v/v/v) at 40 degrees C and detected at 237 nm. The described assay was validated in terms of linearity, accuracy, precision, recovery and lower limit of quantification according to the FDA validation guidelines. Calibration curves were linear with a coefficient of variation (r) greater than 0.998. Accuracy ranged from 92.3% to 106.0% and precision was between 2.3% and 8.2%. The method has been applied to plasma and cerebrospinal fluid samples obtained from patients treated with oxcarbazepine, both in monotherapy and adjunctive therapy.
Knych, Heather K; Stanley, Scott D; Harrison, Linda M; Mckemie, Daniel S
2017-09-01
The use of corticosteroids, such as betamethasone, in performance horses is tightly regulated. The objective of the current study was to describe the plasma pharmacokinetics of betamethasone as well as time-related urine and synovial fluid concentrations following intra-articular administration to horses. Twelve racing-fit adult Thoroughbred horses received a single intra-articular administration (9 mg) of a betamethasone sodium phosphate and betamethasone acetate injectable suspension into the right antebrachiocarpal joint. Blood, urine, and synovial fluid samples were collected prior to and at various times up to 21 days post drug administration. All samples were analyzed using tandem liquid chromatography-mass spectrometry. Plasma data were analyzed using compartmental pharmacokinetic modeling. Maximum measured plasma betamethasone concentrations were 3.97 ± 0.23 ng/mL at 1.45 ± 0.20 h. The plasma elimination half-life was 7.48 ± 0.39 h. Betamethasone concentrations were below the limit of detection in all horses by 96 h and 7 days in plasma and urine, respectively. Betamethasone fell below the limit of detection in the right antebrachiocarpal joint between 14 and 21 days. Results of this study provide information that can be used to regulate the use of intra-articular betamethasone in the horse. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.
Camacho, María; Quintana, María Del Pino; Calabuig, Pascual; Luzardo, Octavio P; Boada, Luis D; Zumbado, Manuel; Orós, Jorge
2015-01-01
The aim of this study was to compare the efficacy and effects on acid-base and electrolyte status of several crystalloid fluids in 57 stranded juvenile loggerhead turtles. Within a rehabilitation program four different crystalloid fluids were administered (0.9% Na Cl solution; 5% dextrose + 0.9% Na Cl solutions 1:1; 0.9% Na Cl + lactated Ringer's solutions 1:1; lactated Ringer's solution). Crystalloid fluids were intracoelomically administered during three days (20 ml/kg/day). Animals were sampled at three different moments: Upon admission for evaluating the type of acid-base or biochemical disorder, post-fluid therapy treatment for controlling the evolution of the disorder, and post-recovery period for obtaining the baseline values for rehabilitated loggerhead turtles. Each sample was analyzed with a portable electronic blood analyzer for pH, pO2, pCO2, lactate, sodium, potassium, chloride, glucose, and BUN concentration. Admission and post-fluid therapy treatment values were compared with those obtained for each turtle immediately before release. The highest percentage of acid-base recovery and electrolyte balance was observed in turtles treated with mixed saline-lactated Ringer's solution (63.6%), followed by turtles treated with physiological saline solution (55%), lactated Ringer's solution (33.3%), and dextrose-saline solutions (10%). Most turtles treated with lactated Ringer's solution had lower lactate concentrations compared with their initial values; however, 66.6% of turtles treated with lactated Ringer's solution had metabolic alkalosis after therapy. Significant higher concentrations of glucose were detected after saline-dextrose administration compared with all the remaining fluids. This is the first study evaluating the effects of several crystalloid fluids on the acid-base status and plasma biochemical values in stranded loggerhead sea turtles. Reference convalescent venous blood gas, acid-base, and plasma biochemical values, useful for veterinary
Tsuchiya, Kiyoto; Ohuchi, Mayu; Yamane, Naoe; Aikawa, Hiroaki; Gatanaga, Hiroyuki; Oka, Shinichi; Hamada, Akinobu
2018-02-01
A simple sample treatment procedure and sensitive liquid chromatography-tandem mass spectrometry method were developed for the simultaneous quantification of the concentrations of human immunodeficiency virus-1 integrase strand transfer inhibitors - raltegravir, dolutegravir and elvitegravir - in human plasma and cerebrospinal fluid (CSF). Plasma and CSF samples (20 μL each) were deproteinized with acetonitrile. Raltegravir-d 3 was used as the internal standard. Chromatographic separation was achieved on an XBridge C 18 column (50 × 2.1 mm i.d., particle size 3.5 μm) using acetonitrile-water (7:3, v/v) containing 0.1% formic acid as the mobile phase at a flow rate of 0.2 mL/min. The run time was 5 min. Calibration curves for all three drugs were linear in the range 5-1500 ng/mL for plasma and 1-200 ng/mL for CSF. The intra- and inter-day precision and accuracy of all three drugs in plasma were coefficient of variation (CV) <12.9% and 100.0 ± 12.2%, respectively, while those in CSF were CV <12.3% and 100.0 ± 7.9%, respectively. Successful validation under the same LC-MS/MS conditions for both plasma and CSF indicates this analytical method is useful for monitoring the levels of these integrase strand transfer inhibitors in the management of treatment of HIV-1 carriers. Copyright © 2017 John Wiley & Sons, Ltd.
Mašek, Martin; Rohlena, Karel
2015-01-01
Roč. 69, č. 4 (2015), s. 109 ISSN 1434-6060 R&D Projects: GA ČR GAP205/11/0571; GA MŠk(CZ) LD14089 Institutional support: RVO:68378271 Keywords : plasma physics * Vlasov equation * numerical-simulation electromagnetic - waves * acceleration Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.208, year: 2015
Carrascal, Montserrat; Gay, Marina; Ovelleiro, David; Casas, Vanessa; Gelpí, Emilio; Abian, Joaquin
2010-02-05
Major plasma protein families play different roles in blood physiology and hemostasis and in immunodefense. Other proteins in plasma can be involved in signaling as chemical messengers or constitute biological markers of the status of distant tissues. In this respect, the plasma phosphoproteome holds potentially relevant information on the mechanisms modulating these processes through the regulation of protein activity. In this work we describe for the first time a collection of phosphopeptides identified in human plasma using immunoaffinity separation of the seven major serum protein families from other plasma proteins, SCX fractionation, and TiO(2) purification prior to LC-MS/MS analysis. One-hundred and twenty-seven phosphosites in 138 phosphopeptides mapping 70 phosphoproteins were identified with FDR search engines.
McLerran, L.
1985-01-01
The author discusses the applicability of a hydrodynamic description of high energy hadronic collisions. The author reviews the results of recent computations of the mean free paths of quarks and gluons in a quark-gluon plasma, and the corresponding results for viscous coefficients. These quantities are employed to evaluate the limits to the application of perfect fluid hydrodynamics as a description of the time evolution of matter produced in various hardronic collisions
Baranets, N.; Ruzhin, Yu.; Dokukin, V.; Ciobanu, M.; Rothkaehl, H.; Kiraga, A.; Vojta, Jaroslav; Šmilauer, Jan; Kudela, K.
2017-01-01
Roč. 59, č. 12 (2017), s. 2951-2968 ISSN 0273-1177 Institutional support: RVO:68378289 Keywords : energy waves * instability * system * beam- plasma interaction * space charge beam waves * pump wave * weak-coupling prediction Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 1.401, year: 2016 http://www.sciencedirect.com/science/article/pii/S0273117717302181
Krishan, S.
2007-01-01
The Stieltjes transform has been used in place of a more common Laplace transform to determine the time evolution of the self-consistent field (SCF) of an unmagnetized semi-infinite plasma, where the plasma electrons together with a primary and a low-density secondary electron beam move perpendicular to the boundary surface. The secondary beam is produced when the primary beam strikes the grid. Such a plasma system has been investigated by Griskey and Stanzel [M. C. Grisky and R. L. Stenzel, Phys. Rev. Lett. 82, 556 (1999)]. The physical phenomenon, observed in their experiment, has been named by them as ''secondary beam instability.'' The character of the instability observed in the experiment is not the same as predicted by the conventional treatments--the field amplitude does not grow with time. In the frequency spectrum, the theory predicts peak values in the amplitude of SCF at the plasma frequency of plasma and secondary beam electrons, decreasing above and below it. The Stieltjes transform for functions, growing exponentially in the long time limit, does not exist, while the Laplace transform technique gives only exponentially growing solutions. Therefore, it should be interesting to know the kind of solutions that an otherwise physically unstable plasma will yield. In the high-frequency limit, the plasma has been found to respond to any arbitrary frequency of the initial field differentiated only by the strength of the resulting SCF. The condition required for exponential growth in the conventional treatments, and the condition for maximum amplitude (with respect to frequency) in the present treatment, have been found to be the same. Nonlinear mode coupling between the modes excited by the plasma electrons and the low-density secondary beam gives rise to two frequency-dependent peaks in the field amplitude, symmetrically located about the much stronger peak due to the plasma electrons, as predicted by the experiment
Noguera Viñas, E C; Hames, W; Mothe, G; Barrionuevo, M P
1989-01-01
Extracellular fluid volume (E.C.F.) and plasma volume (P.V.), were measured with sodium sulfate labeled with 35I and 131I human serum albumin, respectively, by the dilution technique in control subjects and in cirrhotic patients without clinical ascites or edema, renal or hepatic failure, gastrointestinal bleeding or diuretics. Results are expressed as mean +/- DS in both ml/m2 and ml/kg. In normal subjects E.C.F. (n = 8) was 7,533 +/- 817 ml/m2 (201.3 +/- 182 ml/kg), P.V. (n = 11) 1,767 +/- 337 ml/m2 (47.2 +/- 9.3 ml/kg), and interstitial fluid (I.S.F.) (n = 7) 5,758 +/- 851 ml/m2 (Table 2). In cirrhotic patients E.C.F. (n = 11) was 10,318 +/- 2,980 ml/m2 (261.7 +/- 76.8 ml/kg), P.V. (n = 12) 2,649 +/- 558 ml/m2 (67.7 +/- 15.6 ml/kg) and I.S.F. (n = 11) 7,866 +/- 2,987 ml/m2 (Table 3). Cirrhotic patients compared with normal subjects have hypervolemia due to a significant E.C.F. and P.V. expansion (p less than 0.02 and less than 0.001 respectively) (Fig. 1). Reasons for E.C.F. and P.V. abnormalities in cirrhotic patients may reflect urinary sodium retention related to portal hipertension which stimulates aldosterone release or enhanced renal tubular sensitivity to the hormone. However, it is also possible that these patients, in the presence of hypoalbuminemia (Table 1), have no clinical edema or ascites due to increased glomerular filtration, suppressed release of vasopressin, increased natriuretic factor, and urinary prostaglandin excretion, in response to the intravascular expansion, all of which increased solute and water delivery to the distal nephron and improved renal water excretion. We conclude that in our clinical experience cirrhotic patients without ascites or edema have hypervolemia because of a disturbance in E.C.F.
Fokker-Planck code for the quasi-linear absorption of electron cyclotron waves in a tokamak plasma
Meyer, R.L.; Giruzzi, G.; Krivenski, V.
1986-01-01
We present the solution of the kinetic equation describing the quasi-linear evolution of the electron momentum distribution function under the influence of the electron cyclotron wave absorption. Coulomb collisions and the dc electric field in a tokamak plasma. The solution of the quasi-linear equation is obtained numerically using a two-dimensional initial value code following an ADI scheme. Most emphasis is given to the full non-linear and self-consistent problem, namely, the wave amplitude is evaluated at any instant and any point in space according to the actual damping. This is necessary since wave damping is a very sensitive function of the slope of the local momentum distribution function because the resonance condition relates the electron momentum to the location of wave energy deposition. (orig.)
Quasi-linear heating and acceleration in bi-Maxwellian plasmas
Hellinger, Petr; Passot, T.; Sulem, P. L.; Trávníček, Pavel M.
2013-01-01
Roč. 20, č. 12 (2013), 122306/1-122306/6 ISSN 1070-664X R&D Projects: GA ČR GAP209/12/2023; GA ČR GAP209/12/2041 Grant - others:EU(XE) SHOCK Project No. 284515 Institutional support: RVO:67985815 ; RVO:68378289 Keywords : plasma electromagnetic waves * plasma nonlinear phenomena * diffusion Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics; BL - Plasma and Gas Discharge Physics (UFA-U) Impact factor: 2.249, year: 2013
Guiding of laser pulses in plasma waveguides created by linearly-polarized femtosecond laser pulses
Lemos, N.; Cardoso, L.; Geada, J.; Figueira, G.; Albert, F.; Dias, J. M.
2018-01-01
We experimentally demonstrate that plasma waveguides produced with ultra-short laser pulses (sub-picosecond) in gas jets are capable of guiding high intensity laser pulses. This scheme has the unique ability of guiding a high-intensity laser pulse in a plasma waveguide created by the same laser system in the very simple and stable experimental setup. A hot plasma column was created by a femtosecond class laser that expands into an on-axis parabolic low density profile suitable to act as a wav...
Martínez-Gómez, David; Soler, Roberto; Terradas, Jaume, E-mail: david.martinez@uib.es [Departament de Física, Universitat de les Illes Balears, E-07122, Palma de Mallorca (Spain)
2017-03-01
The presence of neutral species in a plasma has been shown to greatly affect the properties of magnetohydrodynamic waves. For instance, the interaction between ions and neutrals through momentum transfer collisions causes the damping of Alfvén waves and alters their oscillation frequency and phase speed. When the collision frequencies are larger than the frequency of the waves, single-fluid magnetohydrodynamic approximations can accurately describe the effects of partial ionization, since there is a strong coupling between the various species. However, at higher frequencies, the single-fluid models are not applicable and more complex approaches are required. Here, we use a five-fluid model with three ionized and two neutral components, which takes into consideration Hall’s current and Ohm’s diffusion in addition to the friction due to collisions between different species. We apply our model to plasmas composed of hydrogen and helium, and allow the ionization degree to be arbitrary. By analyzing the corresponding dispersion relation and numerical simulations, we study the properties of small-amplitude perturbations. We discuss the effect of momentum transfer collisions on the ion-cyclotron resonances and compare the importance of magnetic resistivity, and ion–neutral and ion–ion collisions on the wave damping at various frequency ranges. Applications to partially ionized plasmas of the solar atmosphere are performed.
Wheatley, Vincent; Bond, Daryl; Li, Yuan; Samtaney, Ravi; Pullin, Dale
2017-11-01
The Richtmyer-Meshkov instability (RMI) of a shock accelerated perturbed density interface is important in both inertial confinement fusion and astrophysics, where the materials involved are typically in the plasma state. Initial density interfaces can be due to either temperature or ion-species discontinuities. If the Atwood number of the interfaces and specific heat ratios of the fluids are matched, these two cases behave similarly when modeled using the equations of either hydrodynamics or magnetohydrodynamics. In the two-fluid ion-electron plasma model, however, there is a significant difference between them: In the thermal interface case, there is a discontinuity in electron density that is also subject to the RMI, while for the ion-species interface case there is not. It will be shown via ideal two-fluid plasma simulations that this causes substantial differences in the dynamics of the flow between the two cases. This work was partially supported by the KAUST Office of Sponsored Research under Award URF/1/2162-01.
Knych, Heather K; Harrison, Linda M; White, Alexandria; McKemie, Daniel S
2016-01-01
The use of isoflupredone acetate in performance horses and the scarcity of published pharmacokinetic data necessitate further study. The objective of the current study was to describe the plasma pharmacokinetics of isoflupredone acetate as well as time-related urine and synovial fluid concentrations following intra-articular administration to horses. Twelve racing-fit adult Thoroughbred horses received a single intra-articular administration (8 mg) of isoflupredone acetate into the right antebrachiocarpal joint. Blood, urine and synovial fluid samples were collected prior to and at various times up to 28 days post drug administration. All samples were analyzed using liquid chromatography-Mass Spectrometry. Plasma data were analyzed using a population pharmacokinetic compartmental model. Maximum measured plasma isoflupredone concentrations were 1.76 ± 0.526 ng/mL at 4.0 ± 1.31 h and 1.63 ± 0.243 ng/mL at 4.75 ± 0.5 h, respectively, for horses that had synovial fluid collected and for those that did not. The plasma beta half-life was 24.2 h. Isoflupredone concentrations were below the limit of detection in all horses by 48 h and 7 days in plasma and urine, respectively. Isoflupredone was detected in the right antebrachiocarpal and middle carpal joints for 8.38 ± 5.21 and 2.38 ± 0.52 days, respectively. Results of this study provide information that can be used to regulate the use of intra-articular isoflupredone in the horse. Copyright © 2015 John Wiley & Sons, Ltd.
Coaxial plasma guns as injectors of high beta linear theta pinches
Marshall, J.
1975-01-01
A brief review of research on coaxial plasma guns and their use is given. Some problems and possibilities of using this gun for beam injection experiments are pointed out. Some scaling laws for gun energy are described
On the balance of a linear plasma column confined in a transverse magnetic field
Lehnert, B.
1978-08-01
The equilibrium features are investigated of a straight plasma column being confined in a purely transverse magnetic field, part of which is being generated by external conductors. Provided that stability can be secured at high beta values, the reduced transport of particles and heat in the axial direction should allow for large axial temperature gradients. It is then expected that temperatures even leading to ignition can be achieved in a pure plasma, at technically realistic column lengths. (author)
Linear and nonlinear ion beam instabilities in a double plasma device
Lee, S.G.; Diebold, D.; Hershkowitz, N.
1994-01-01
Ion beam instabilities in the double plasma device DOLI-1 were found to be quite sensitive to the difference between the source and target chamber plasma potentials when those potentials were within an electron temperature T e /e or so of each other. When the target chamber plasma potential of DOLI-1 was ≤ T e /e more positive than the source chamber plasma potential, a global ion beam-ion beam instability was observed. On the other hand, when the maximum target potential was between approximately 0.5 T e /e and 2.0 T e /e below the source potential, an ion-ion beam instability and a soliton associated with it were observed. This soliton is unique in that it is not launched but rather is self generated by the plasma and beam. When the target potential was less than source potential by more than two or so T e /e, the plasma was quite quiescent, which allowed small amplitude wave packet launched by Langmuir probe to be detected
Martínez-Gómez, David; Soler, Roberto; Terradas, Jaume, E-mail: david.martinez@uib.es [Departament de Física, Universitat de les Illes Balears, E-07122, Palma de Mallorca (Spain)
2016-12-01
Ideal magnetohydrodynamics (MHD) provides an accurate description of low-frequency Alfvén waves in fully ionized plasmas. However, higher-frequency waves in many plasmas of the solar atmosphere cannot be correctly described by ideal MHD and a more accurate model is required. Here, we study the properties of small-amplitude incompressible perturbations in both the low- and the high-frequency ranges in plasmas composed of several ionized species. We use a multi-fluid approach and take into account the effects of collisions between ions and the inclusion of Hall’s term in the induction equation. Through the analysis of the corresponding dispersion relations and numerical simulations, we check that at high frequencies ions of different species are not as strongly coupled as in the low-frequency limit. Hence, they cannot be treated as a single fluid. In addition, elastic collisions between the distinct ionized species are not negligible for high-frequency waves, since an appreciable damping is obtained. Furthermore, Coulomb collisions between ions remove the cyclotron resonances and the strict cutoff regions, which are present when collisions are not taken into account. The implications of these results for the modeling of high-frequency waves in solar plasmas are discussed.
Fu, X.; Li, H.; Guo, F.; Li, X.; Roytershteyn, V.
2017-12-01
The solar wind is a turbulent magnetized plasma extending from the upper atmosphere of the sun to the edge of the heliosphere. It carries charged particles and magnetic fields originated from the Sun, which have great impact on the geomagnetic environment and human activities in space. In such a magnetized plasma, Alfven waves play a crucial role in carrying energy from the surface of the Sun, injecting into the solar wind and establishing power-law spectra through turbulent energy cascades. On the other hand, in compressible plasmas large amplitude Alfven waves are subject to a parametric decay instability (PDI) which converts an Alfven wave to another counter-propagating Alfven wave and an ion acoustic wave (slow mode). The counter-propagating Alfven wave provides an important ingredient for turbulent cascade, and the slow-mode wave provides a channel for solar wind heating in a spatial scale much larger than ion kinetic scales. Growth and saturation of PDI in quiet plasma have been intensively studied using linear theory and nonlinear simulations in the past. Here using 3D hybrid simulations, we show that PDI is still effective in turbulent low-beta plasmas, generating slow modes and causing ion heating. Selected events in WIND data are analyzed to identify slow modes in the solar wind and the role of PDI, and compared with our simulation results. We also investigate the validity of linear Vlasov theory regarding PDI growth and slow mode damping in turbulent plasmas. Since PDI favors low plasma beta, we expect to see more evidence of PDI in the solar wind close to the Sun, especially from the upcoming NASA's Parker Solar Probe mission which will provide unprecedented wave and plasma data as close as 8.5 solar radii from the Sun.
Maddison, G.P.; Reiter, D.
1994-02-01
Predictive simulations of tokamak edge plasmas require the most authentic description of neutral particle recycling sources, not merely the most expedient numerically. Employing a prototypical ITER divertor arrangement under conditions of high recycling, trial calculations with the 'B2' steady-state edge plasma transport code, plus varying approximations or recycling, reveal marked sensitivity of both results and its convergence behaviour to details of sources incorporated. Comprehensive EIRENE Monte Carlo resolution of recycling is implemented by full and so-called 'shot' intermediate cycles between the plasma fluid and statistical neutral particle models. As generally for coupled differencing and stochastic procedures, though, overall convergence properties become more difficult to assess. A pragmatic criterion for the 'B2'/EIRENE code system is proposed to determine its success, proceeding from a stricter condition previously identified for one particular analytic approximation of recycling in 'B2'. Certain procedures are also inferred potentially to improve their convergence further. (orig.)
Gredal, Hanne; Thomsen, Barbara B; Boza-Serrano, Antonio
2017-01-01
itself contributes towards the cytokine response. Community-dwelling domestic dogs suffer from spontaneous ischaemic stroke, and therefore, offer the opportunity to study the cytokine response in a noninvasive set-up. The aims of this study were to investigate cytokine concentrations in plasma...... and cerebrospinal fluid (CSF) in dogs with acute ischaemic stroke and to search for correlations between infarct volume and cytokine concentrations. Blood and CSF were collected from dogs less than 72 h after a spontaneous ischaemic stroke. Infarct volumes were estimated on MRIs. Interleukin (IL)-2, IL-6, IL-8, IL......-10 and tumour necrosis factor in the plasma, CSF and brain homogenates were measured using a canine-specific multiplex immunoassay. IL-6 was significantly increased in plasma (P = 0.04) and CSF (P = 0.04) in stroke dogs compared with healthy controls. The concentrations of other cytokines...
Waves and Oscillations in Plasmas
Pecseli, Hans L
2012-01-01
The result of more than 15 years of lectures in plasma sciences presented at universities in Denmark, Norway, and the United States, Waves and Oscillations in Plasmas addresses central issues in modern plasma sciences. The book covers fluid models as well as kinetic plasma models, including a detailed discussion of, for instance, collisionless Landau damping. Offering a clear separation of linear and nonlinear models, the book can be tailored for readers of varying levels of expertise.Designed to provide basic training in linear as well as nonlinear plasma dynamics, and practical in areas as d
Cannamela, Michael J., III
The plasma spray process uses plasma flames to melt micron sized particles of e.g. ceramic and propel the droplets to impinge upon and freeze to the target workpiece, forming a functional coating. Variations in the process arise from many sources, and because sensing of the process is imperfect one is motivated to pursue a modeling approach. This dissertation models the major elements of the process; the torch that produces the plasma flame, the jet of hot plasma issuing from the torch, and the plume of particles conveyed and heated by the jet. The plasma in the torch is modeled by a one-fluid magnetohydrodynamic (MHD) approach and it is found that the MHD equations can accurately predict the power dissipated in the bulk of the plasma, while special treatment is required in regions near the electrodes. Treatment of the cathode region is eased since it can be de-coupled from the bulk flow. Treatment of the anode region aims to extract the correct amount of power from the plasma. With MHD in the bulk and these special conditions at the electrode boundaries, the net power into the plasma can be matched with experiment. For one simulation of an SG-100 torch operating at 500A, the measured net power was 7.0kW while the computed net power was 7.1kW. Using outlet information from the torch, the impact of plasma arc oscillations on the free jet and on the in-flight particle states is predicted. The model of the plasma jet is validated against the existing LAVA code, and is able to predict the fraction of entrained air in the jet to within 20% of the experimental value. The variations in particle states due to the arc fluctuations are found to be similar in size to variations due to changes in particle injection velocity, and so cannot be neglected when considering particle state distributions. The end result of this work is to make available a complete chain of models for the plasma spray process, from torch input conditions to in-flight particle state.
Optics and Fluid Dynamics Department annual progress report for 2003
Bindslev, H.; Hanson, Steen Grüner; Lynov, Jens-Peter; Petersen, Paul Michael; Skaarup, Bitten
2004-01-01
The Optics and Fluid Dynamics Department performs basic and applied research within three scientific programmes: (1) laser systems and optical materials, (2) optical diagnostics and information processing and (3) plasma and fluid dynamics. The departmenthas core competences in: optical sensors, optical materials, optical storage, biophotonics, numerical modelling and information processing, non-linear dynamics, fusion plasma physics and plasma technology. The research is supported by several ...
Optics and Fluid Dynamics Department annual progress report for 2003
Bindslev, H.; Hanson, Steen Grüner; Lynov, Jens-Peter
2004-01-01
The Optics and Fluid Dynamics Department performs basic and applied research within three scientific programmes: (1) laser systems and optical materials, (2) optical diagnostics and information processing and (3) plasma and fluid dynamics. The departmenthas core competences in: optical sensors......, optical materials, optical storage, biophotonics, numerical modelling and information processing, non-linear dynamics, fusion plasma physics and plasma technology. The research is supported by several EUprogrammes, including EURATOM, by Danish research councils and by industry. A summary of the activities...
Linear and nonlinear waves with orbital angular momentum in magnetized plasma
Ali, Shahid; Kant Shukla, Padma; Tito Mendonca, José.
2009-11-01
Here we discuss the concept of orbital angular momentum (OAM) for electromagnetic waves in a magnetized plasma. Nonlinear effects of photons with spin and OAM will be considered. In particular, we examine the case of parametric interactions between circularly polarized electromagnetic waves and Langmuir and ion acoustic waves, including the ponderomotive force of light with OAM in magnetized plasma (Shukla & Stenflo, PRA). This will be a generalization of recent results published in PRL by J.T. Mendonca and B. Thide. We also examine the influence of OAM on the magnetic field generation by the inverse Faraday effect.
Clauser, Johanna; Knieps, Marius S; Büsen, Martin; Ding, Andreas; Schmitz-Rode, Thomas; Steinseifer, Ulrich; Arens, Jutta; Cattaneo, Giorgio
2018-02-27
Particle image velocimetry (PIV) is a commonly used method for in vitro investigation of fluid dynamics in biomedical devices, such as flow diverters for intracranial aneurysm treatment. Since it is limited to transparent blood substituting fluids like water-glycerol mixture, the influence of coagulation and platelet aggregation is neglected. We aimed at the development and the application of a modified platelet rich plasma as a new PIV fluid with blood-like rheological and coagulation properties. In standardized intracranial aneurysm silicone models, the effect of this new PIV plasma on the fluid dynamics before and after flow diverter implantation was evaluated and compared with water-glycerol measurements. The flow diverting effect was strongly dependent on the used fluid, with considerably lower velocities achieved using PIV plasma, despite the same starting viscosity of both fluids. Moreover, triggering coagulation of PIV plasma allowed for intra-aneurysmal clot formation. We presented the first in vitro PIV investigation using a non-Newtonian, clottable PIV plasma, demonstrating a mismatch to a standard PIV fluid and allowing for thrombus formation.
Laguardia, L., E-mail: laguardia@ifp.cnr.it [CNR, Istituto di Fisica del Plasma“P. Caldirola”, Milan (Italy); Caniello, R.; Cremona, A. [CNR, Istituto di Fisica del Plasma“P. Caldirola”, Milan (Italy); Dellasega, D. [CNR, Istituto di Fisica del Plasma“P. Caldirola”, Milan (Italy); Politecnico di Milano, Dipartimento di Energia, Milan (Italy); Dell’Era, F.; Ghezzi, F.; Gittini, G.; Granucci, G.; Mellera, V.; Minelli, D.; Pallotta, F. [CNR, Istituto di Fisica del Plasma“P. Caldirola”, Milan (Italy); Passoni, M. [CNR, Istituto di Fisica del Plasma“P. Caldirola”, Milan (Italy); Politecnico di Milano, Dipartimento di Energia, Milan (Italy); Ricci, D.; Vassallo, E. [CNR, Istituto di Fisica del Plasma“P. Caldirola”, Milan (Italy)
2015-08-15
In this work results of the first D{sub 2}/N{sub 2} experiments in GyM, a linear device able to produce plasmas of interest for the ITER divertor (n{sub e} 5 ⋅ 10{sup 10} cm{sup −3}, Te 5 eV, ion flux 3–5 ⋅ 10{sup 20} m{sup −2}s{sup −1}) are presented. Plasmas simulating a N-seeding scenario have been performed to evaluate ammonia formation and its effect on exposed W coatings. The presence of ND emission lines in the plasma can be correlated with the formation of ammonia, further directly detected and quantified by chromatography analysis of the exhaust. Four different W specimens were exposed in GyM to a plasma fluence of 8.78 ⋅ 10{sup 23} m{sup −2}. XPS analysis evidenced the formation of W{sub x}N{sub y} layers with nitrogen concentration in the range of 1–10% depending on the initial morphology and structure of the W samples. In all analyzed cases, nitrogen was bound and retained within the first 6 nm below the surface and no further diffusion of N into the bulk was observed.
Fendrych, Frantisek; Taylor, Andrew; Peksa, Ladislav; Kratochvilova, Irena; Kluiber, Zdenek; Fekete, Ladislav [Institute of Physics, Academy of Sciences of the Czech Republic, v.v.i, Na Slovance 2, CZ-18221 Prague 8 (Czech Republic); Vlcek, Jan [Department of Physics and Measurement, Institute of Chemical Technology Prague, Technicka 5, CZ-16628 Prague 6 (Czech Republic); Rezacova, Vladimira; Petrak, Vaclav [Faculty of Biomedical Engineering, Czech Technical University, Sitna 3105, CZ-27201 Kladno 2 (Czech Republic); Liehr, Michael [Leybold Optics Dresden GmbH, Zur Wetterwarte 50, D-01109 Dresden (Germany); Nesladek, Milos, E-mail: fendrych@fzu.c [IMOMEC division, IMEC, Institute for Materials Research, University Hasselt, Wetenschapspark 1, B-3590 Diepenbeek (Belgium)
2010-09-22
Industrial applications of plasma-enhanced chemical vapour deposition (CVD) diamond grown on large area substrates, 3D shapes, at low substrate temperatures and on standard engineering substrate materials require novel plasma concepts. Based on the pioneering work of the group at AIST in Japan, the high-density coaxial delivery type of plasmas has been explored (Tsugawa et al 2006 New Diamond Front. Carbon Technol. 16 337-46). However, an important challenge is to obtain commercially interesting growth rates at very low substrate temperatures. In this work we introduce the concept of novel linear antenna sources, designed at Leybold Optics Dresden, using high-frequency pulsed MW discharge with a high plasma density. This type of pulse discharges leads to the preparation of nanocrystalline diamond (NCD) thin films, compared with ultra-NCD thin films prepared in (Tsugawa et al 2006 New Diamond Front. Carbon Technol. 16 337-46). We present optical emission spectroscopy data for the CH{sub 4}-CO{sub 2}-H{sub 2} gas chemistry and we discuss the basic properties of the NCD films grown.
Martínez Carapeto, Isabel; López Castilla, José Domingo; Fresneda Gutiérrez, Reyes
2017-11-11
To compare plasma glucose levels and incidence of hyperglycaemia in the post-operative period after general surgery using fluids with different glucose. A randomised, open-label, non-blind, clinical trial was conducted on patients admitted to Paediatric Intensive Care Unit after elective surgery. The inclusion criteria were from 6 months to 14 years of age, with a weight greater than 6kg, onset glucose level >60mg/dL, and a signed informed consent, with no oral intake and maintenance intravenous fluid therapy using fluids with 3.3% or 5% glucose. Plasma glucose levels were measured before surgery, on admission, and 8, 24, and 48h, with the mean glucose levels and incidence of hyperglycaemia (glucose level >150mg/dL) in both groups being compared. A total of 60 patients received glucose/saline 1/3 (51mEq/L sodium and 33g/L glucose), and 70 glucose/saline 5/0.9% (154mEq/L sodium and 50g/L glucose). Mean glucose levels were higher in the group receiving glucose 5%, with no statistical difference. There was no significant difference in the incidence of hyperglycaemia; 8h: 26% in the 3.3% group vs. 21.3% in the 5% group (P=.63); 24h: 20% vs. 22.7% (P=.8); and 48h: 19% vs. 23.1% (P=.78). The use of fluids with 3.3% glucose in the post-operative period of general surgery maintains mean glucose levels in a similar range to that of patients receiving fluids with 5% glucose, with no difference in the incidence of hyperglycaemia. Copyright © 2017. Publicado por Elsevier España, S.L.U.
Saitou, Y.; Yonesu, A.; Shinohara, S.; Ignatenko, M. V.; Kasuya, N.; Kawaguchi, M.; Terasaka, K.; Nishijima, T.; Nagashima, Y.; Kawai, Y.; Yagi, M.; Itoh, S.-I.; Azumi, M.; Itoh, K.
2007-01-01
The importance of reducing the neutral density to reach strong drift wave turbulence is clarified from the results of the extended magnetohydrodynamics and Monte Carlo simulations in a linear magnetized plasma. An upper bound of the neutral density relating to the ion-neutral collision frequency for the excitation of drift wave instability is shown, and the necessary flow velocity to excite this instability is also estimated from the neutral distributions. Measurements of the Mach number and the electron density distributions using Mach probe in the large mirror device (LMD) of Kyushu University [S. Shinohara et al., Plasma Phys. Control. Fusion 37, 1015 (1995)] are reported as well. The obtained results show a controllability of the neutral density and provide the basis for neutral density reduction and a possibility to excite strong drift wave turbulence in the LMD
Theory of neutron spectra from d-d-reactions in the linear z-pinch and the plasma focus
Deutsch, R.; Kaeppeler, H.J.
1982-05-01
Because of a finite gyroradius effect, the equilibrium probability density function of the ions in the azimuthal magnetic field of a linear z-pinch becomes anisotropic. This density function was derived by solving the Vlasov equation and used to determine the neutron spectra produced in the deuterium plasma of a z-pinch. The neutron spectra were calculated for two models, differing in the energy distribution of the fast ions. A background plasma with 'slow' ions was also considered. The interactions of the fast ions with the slow ions and 'beam-beam' interactions between fast ions were considered. Typical spectra for arbitrary directions to the cylindrical axis are given. The anisotropy factors were calculated. Considering the influence of the azimuthal magnetic field on the equilibrium density function of the deuterons, the well known particularities of the neutron spectra are obtained without any of the contradictions typical of the traditional models. (orig.)
Phase-space description of plasma waves. Linear and nonlinear theory
Biro, T.
1992-11-01
We develop an (r,k) phase space description of waves in plasmas by introducing Gaussian window functions to separate short scale oscillations from long scale modulations of the wave fields and variations in the plasma parameters. To obtain a wave equation that unambiguously separates conservative dynamics from dissipation also in an inhomogeneous and time varying background plasma, we first discuss the proper form of the current response function. On the analogy of the particle distribution function f(v,r,t), we introduce a wave density N(k,r,t) on phase space. This function is proven to satisfy a simple continuity equation. Dissipation is also included, and this allows us to describe the damping or growth of wave density' along rays. Problems involving geometric optics of continuous media often appear simpler when viewed in phase space, since the flow of N in phase space is incompressible. Within the phase space representation, we obtain a very general formula for the second order nonlinear current in terms of the vector potential. This formula is a convenient starting point for studies of coherent as well as turbulent nonlinear processes. We derive kinetic equations for weakly inhomogeneous and turbulent plasma, including the effects of inhomogeneous turbulence, wave convection and refraction. (author)
Quasi-linear theory for a tokamak plasma in the presence of cyclotron resonance
Belikov, V.S.; Kolesnichenko, Ya.I.
1993-01-01
Quasi-linear diffusion equations for the distribution function of trapped and circulating particles interacting with waves in a tokamak by means of cyclotron resonance are derived. The resulting equations reveal new features of quasi-linear diffusion and are of two kinds, one which involves bounce resonances overlapping in velocity space and one with well separated bounce resonances. These two cases correspond to situations where the phase of the wave-particle interaction between successive resonances can be considered as random or deterministic, respectively. An analysis of the conditions of applicability of the new equations is carried out and previous well-known forms of the quasi-linear diffusion equations are shown to be recovered in the proper limits. (10 refs., 3 figs.)
Carlson, Gary P
2010-01-01
Styrene is a widely used chemical, but it is known to produce lung and liver damage in mice. This may be related to oxidative stress associated with the decrease in the levels of reduced glutathione (GSH) in the target tissues. The purpose of this study was to investigate the effect of styrene and its primary metabolites R-styrene oxide (R-SO) and S-styrene oxide (S-SO) on GSH levels in the lung lumen, as determined by amounts of GSH in bronchioalveolar lavage fluid (BALF) and in plasma. When non-Swiss albino (NSA) mice were administered styrene (600 mg/kg, ip), there was a significant fall in GSH levels in both BALF and plasma within 3 h. These returned to control levels by 12 h. The active metabolite R-SO (300 mg/kg, ip) also produced significant decreases in GSH in both BALF and plasma, but S-SO was without marked effect. Since GSH is a principal antioxidant in the lung epithelial lining fluid, this fall due to styrene may exert a significant influence on the ability of the lung to buffer oxidative damage.
Numerical study of two-fluid flowing equilibria of helicity-driven spherical torus plasmas
Kanki, T.; Nagata, M.; Uyama, T.
2004-01-01
Two-fluid flowing equilibrium configurations of a helicity-driven spherical torus (HD-ST) are numerically determined by using the combination of the finite difference and the boundary element methods. It is found from the numerical results that electron fluids near the central conductor are tied to an external toroidal field and ion fluids are not. The magnetic configurations change from the high-q HD-ST (q>1) with paramagnetic toroidal field and low-β (volume average β value, ∼ 2%) through the helicity-driven spheromak and RFP (reverse field pinch) to the ultra low-q HD-ST (0 ∼ 18%) as the external toroidal field at the inner edge regions decreases and reverses the sign. The two-fluid effects are more significant in this equilibrium transition when the ion diamagnetic drift is dominant in the flowing two-fluid. (authors)
Mathematical and numerical study of non-linear models used in plasma physics
Ebrard, G.
2005-12-01
We study the interaction of several crossing beams with a plasma in the Laser-Megajoule context. We start from Euler-Maxwell. The formal asymptotic is the Zakharov system. For simplified systems of Klein-Gordon-wave type, we justify an approximation by a Zakharov equation for solutions of large amplitude. We construct a new system that simulates the interaction of 2 beams and present a whole hierarchy of models. We introduce a numerical scheme using the known results on Zakharov-wave equations which are valid for short pulses. We give a scheme which eliminate the backscattering wave. We give some numerical results. Finally, we do several numerical simulations of laser-plasma interaction for the initial value problem and the boundary value problem. (author)
Comment on “Beamstrahlung considerations in laser-plasma-accelerator-based linear colliders”
Valeri Lebedev
2013-10-01
Full Text Available Schroeder, Esarey, Geddes, Benedetti, and Leemans [Phys. Rev. ST Accel. Beams 13, 101301 (2010PRABFM1098-440210.1103/PhysRevSTAB.13.101301 and Phys. Rev. ST Accel. Beams 15, 051301 (2012PRABFM1098-440210.1103/PhysRevSTAB.15.051301] have proposed a set of parameters for a TeV-scale collider based on plasma wakefield accelerator principles. In particular, it is sugested that the luminosities greater than 10^{34} cm^{-2} s^{-1} are attainable for an electron-positron collider. In this Comment we dispute this set of parameters on the basis of first principles. The interactions of accelerating beam with plasma impose fundamental limitations on beam properties and, thus, on attainable luminosity values.
Non-linear magnetohydrodynamic modeling of plasma response to resonant magnetic perturbations
Orain, F.; Bécoulet, M.; Dif-Pradalier, G.; Huijsmans, G.; Pamela, S.; Nardon, E.; Passeron, C.; Latu, G.; Grandgirard, V.; Fil, A.; Ratnani, A.; Chapman, I.; Kirk, A.; Thornton, A.; Hoelzl, M.; Cahyna, Pavel
2013-01-01
Roč. 20, č. 10 (2013), s. 102510-102510 ISSN 1070-664X R&D Projects: GA ČR GAP205/11/2341 Institutional support: RVO:61389021 Keywords : tokamak * edge localized mode * magnetohydrodynamics Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 2.249, year: 2013 http://scitation.aip.org/content/aip/journal/pop/20/10/10.1063/1.4824820
Study of ICRF wave propagation and plasma coupling efficiency in a linear magnetic mirror device
Peng, S.Y.
1991-07-01
Ion Cyclotron Range of Frequency (ICRF) wave propagation in an inhomogeneous axial magnetic field in a cylindrical plasma-vacuum system has historically been inadequately modelled. Previous works either sacrifice the cylindrical geometry in favor of a simpler slab geometry, concentrate on the resonance region, use a single mode to represent the entire field structure, or examine only radial propagation. This thesis performs both analytical and computational studies to model the ICRF wave-plasma coupling and propagation problem. Experimental analysis is also conducted to compare experimental results with theoretical predictions. Both theoretical as well as experimental analysis are undertaken as part of the thesis. The theoretical studies simulate the propagation of ICRF waves in an axially inhomogeneous magnetic field and in cylindrical geometry. Two theoretical analysis are undertaken - an analytical study and a computational study. The analytical study treats the inhomogeneous magnetic field by transforming the (r,z) coordinate into another coordinate system (ρ,ξ) that allows the solution of the fields with much simpler boundaries. The plasma fields are then Fourier transformed into two coupled convolution-integral equations which are then differenced and solved for both the perpendicular mode number α as well as the complete EM fields. The computational study involves a multiple eigenmode computational analysis of the fields that exist within the plasma-vacuum system. The inhomogeneous axial field is treated by dividing the geometry into a series of transverse axial slices and using a constant dielectric tensor in each individual slice. The slices are then connected by longitudinal boundary conditions
Screening of ionic cores in partially ionized plasmas within linear response
Gericke, D. O.; Vorberger, J.; Wuensch, K.; Gregori, G.
2010-01-01
We employ a pseudopotential approach to investigate the screening of ionic cores in partially ionized plasmas. Here, the effect of the tightly bound electrons is condensed into an effective potential between the (free) valence electrons and the ionic cores. Even for weak electron-ion coupling, the corresponding screening clouds show strong modifications from the Debye result for elements heavier than helium. Modifications of the theoretically predicted x-ray scattering signal and implications on measurements are discussed.
Hansen, J S; Daivis, Peter J; Todd, B D
2009-10-01
In this paper we present equilibrium molecular-dynamics results for the shear, rotational, and spin viscosities for fluids composed of linear molecules. The density dependence of the shear viscosity follows a stretched exponential function, whereas the rotational viscosity and the spin viscosities show approximately power-law dependencies. The frequency-dependent shear and spin viscosities are also studied. It is found that viscoelastic behavior is first manifested in the shear viscosity and that the real part of the spin viscosities features a maximum for nonzero frequency. The calculated transport coefficients are used together with the extended Navier-Stokes equations to investigate the effect of the coupling between the intrinsic angular momentum and linear momentum for highly confined fluids. Both steady and oscillatory flows are studied. It is shown, for example, that the fluid flow rate for Poiseuille flow is reduced by up to 10% in a 2 nm channel for a buta-triene fluid at density 236 kg m(-3) and temperature 306 K. The coupling effect may, therefore, become very important for nanofluidic applications.
High resolution Thomson scattering system for steady-state linear plasma sources
Lee, K. Y.; Lee, K. I.; Kim, J. H.; Lho, T.
2018-01-01
The high resolution Thomson scattering system with 63 points along a 25 mm line measures the radial electron temperature (Te) and its density (ne) in an argon plasma. By using a DC arc source with lanthanum hexaboride (LaB6) electrode, plasmas with electron temperature of over 5 eV and densities of 1.5 × 1019 m-3 have been measured. The system uses a frequency doubled (532 nm) Nd:YAG laser with 0.25 J/pulse at 20 Hz. The scattered light is collected and sent to a triple-grating spectrometer via optical-fibers, where images are recorded by an intensified charge coupled device (ICCD) camera. Although excellent in stray-light reduction, a disadvantage comes with its relatively low optical transmission and in sampling a tiny scattering volume. Thus requires accumulating multitude of images. In order to improve photon statistics, pixel binning in the ICCD camera as well as enlarging the intermediate slit-width inside the triple-grating spectrometer has been exploited. In addition, the ICCD camera capture images at 40 Hz while the laser is at 20 Hz. This operation mode allows us to alternate between background and scattering shot images. By image subtraction, influences from the plasma background are effectively taken out. Maximum likelihood estimation that uses a parameter sweep finds best fitting parameters Te and ne with the incoherent scattering spectrum.
Nonlinear fluid equations for fully toroidal electromagnetic waves for the core tokamak plasma
Weiland, J.; Liu, C. S.; Liu
2013-12-01
The rather general set of fluid equations with full curvature effects (Shukla and Weiland, Phys. Rev. A 40, 341 (1989)) has been modified to apply to the core and generalized to include also microtearing modes.
Fendrych, František; Taylor, Andrew; Peksa, Ladislav; Kratochvílová, Irena; Vlček, J.; Řezáčová, V.; Petrák, V.; Kluiber, Z.; Fekete, Ladislav; Liehr, M.; Nesládek, M.
2010-01-01
Roč. 43, č. 37 (2010), 374018/1-374018/6 ISSN 0022-3727 R&D Projects: GA AV ČR KAN200100801; GA AV ČR KAN300100801; GA AV ČR KAN301370701 Institutional research plan: CEZ:AV0Z10100520 Keywords : nanodiamond, * thin films * PE MW CVD * linear antennas Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.105, year: 2010
Van Toi, Pham; Pouplin, Thomas; Tho, Nguyen Duc Khanh; Phuong, Pham Nguyen; Chau, Tran Thi Hong; Thuong Thuong, Nguyen Thuy; Heemskerk, Dorothee; Hien, Tran Tinh; Thwaites, Guy E
2017-09-01
An accurate and reliable high-performance liquid chromatography with time-programmed fluorescence detection was developed and validated to measure levofloxacin in human plasma and cerebrospinal fluid (CSF). After solid phase extraction process using Evolute ® ABN 96 fixed well plate; levofloxacin and internal standard-enoxacin were separated using a mobile phase consisting of phosphate buffer 10mM with 0.025% triethylamine pH 3.0 - acetonitrile (88:12, v/v) on a Purosphere RP-8e column (5μm, 125×4.0mm) at a flow rate of 1.2mL/min at 35°C. The excitation/emission wavelengths were set to 269/400nm and 294/500nm, for enoxacin and levofloxacin, respectively. The method was linear over the concentration range of 0.02 to 20.0μg/mL with a limit of detection of 0.01μg/mL. The relative standard deviation of intra-assay and inter-assay precision for levofloxacin at four quality controls concentrations (0.02, 0.06, 3.0 and 15.0μg/mL) were less than 7% and the accuracies ranged from 96.75% to 101.9% in plasma, and from 93.00% to 98.67% in CSF. The validated method was successfully applied to quantify levofloxacin in a considerable quantity of plasma (826) and CSF (477) samples collected from 232 tuberculous meningitis patients, and the preliminary intensive pharmacokinetics analysis from 14 tuberculous meningitis patients in Vietnam is described in this paper. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.
Paulo Pereira Christo
2011-08-01
Full Text Available The question of whether HIV-1 RNA in cerebrospinal fluid (CSF is derived from viral replication in the central nervous system or simply reflects the transit of infected lymphocytes from the blood compartment has long been a matter of debate. Some studies found no correlation between CSF and plasma viral load, whereas others did. The lack of a correlation between the two compartments suggests that the presence of HIV-1 RNA is not simply due to the passive passage of the virus from blood to CSF but rather due to intrathecal replication. To evaluate the correlation between plasma and CSF HIV-1 RNA levels and to identify situations in which there is no correlation between the two compartments, seventy patients were prospectively studied. The association between CSF and plasma viral load was evaluated in the total population and in subgroups of patients with similar characteristics. A correlation between the CSF and plasma compartments was observed for patients undergoing highly active antiretroviral therapy (HAART, those with a CD4 T lymphocyte count lower than 200 cells/mm³, and those with increased CSF protein content. On the other hand, no correlation was observed for patients without adequate virological control, who had a CD4 count higher than 200 cells/mm³ and who did not use HAART. The correlation between the two compartments observed in some patients suggests that CSF HIV-1 RNA levels may reflect plasma levels in these subjects. In contrast, the lack of a correlation between the two compartments in patients who were not on HAART and who had normal CSF proteins and a poor virological control possibly indicates compartmentalization of the virus in CSF and, consequently, plasma-independent intrathecal viral replication.
Lalousis, P.
1984-01-01
Nonthermal direct electrodynamic interaction between laser energy and a fully ionized plasma was studied. The particular emphasis is on the action of nonlinear forces, in which the optical electromagnetic fields act on the plasma electrons which then transfer their energy to the ions electrostatically. Instead of the usual single fluid model, the plasma is treated as two separate conducting fluids for electrons and ions, coupled by momentum and Coulomb interactions. The equations governing the two fluids are derived from first principles, and numerical algorithms for computing these equations are developed, enabling the plasma oscillatons to be resolved and studied. Fully ionized plasma expansion without laser irradiation is studied first numerically. Remarkable damping mechanisms by coupling to ion oscillations have been observed. Inhomogeneities in densities of the two fluids result in large electrostatic fields and double layers are generated. There is quite close agreement between numerically calculated electrostatic fields and analytical solutions. Laser interaction with fully ionized plasma is also studied numerically. The generation of cavitons is numerically observed, and it is inferred that laser plasma interactions produce very high electrostatic fields in the vicinity of cavitons. It is further shown that charge neutrality is not necessarily maintained in a caviton
Spectral survey of helium lines in a linear plasma device for use in HELIOS imaging
Ray, H. B., E-mail: rayhb@ornl.gov [University of Tennessee, Knoxville, Tennessee 37996 (United States); Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Biewer, T. M.; Fehling, D. T.; Isler, R. C.; Unterberg, E. A. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)
2016-11-15
Fast visible cameras and a filterscope are used to examine the visible light emission from Oak Ridge National Laboratory’s Proto-MPEX. The filterscope has been configured to perform helium line ratio measurements using emission lines at 667.9, 728.1, and 706.5 nm. The measured lines should be mathematically inverted and the ratios compared to a collisional radiative model (CRM) to determine T{sub e} and n{sub e}. Increasing the number of measurement chords through the plasma improves the inversion calculation and subsequent T{sub e} and n{sub e} localization. For the filterscope, one spatial chord measurement requires three photomultiplier tubes (PMTs) connected to pellicle beam splitters. Multiple, fast visible cameras with narrowband filters are an alternate technique for performing these measurements with superior spatial resolution. Each camera contains millions of pixels; each pixel is analogous to one filterscope PMT. The data can then be inverted and the ratios compared to the CRM to determine 2-dimensional “images” of T{sub e} and n{sub e} in the plasma. An assessment is made in this paper of the candidate He I emission lines for an imaging technique.
Spectral survey of helium lines in a linear plasma device for use in HELIOS imaging
Ray, H. B.; Biewer, T. M.; Fehling, D. T.; Isler, R. C.; Unterberg, E. A.
2016-11-01
Fast visible cameras and a filterscope are used to examine the visible light emission from Oak Ridge National Laboratory's Proto-MPEX. The filterscope has been configured to perform helium line ratio measurements using emission lines at 667.9, 728.1, and 706.5 nm. The measured lines should be mathematically inverted and the ratios compared to a collisional radiative model (CRM) to determine Te and ne. Increasing the number of measurement chords through the plasma improves the inversion calculation and subsequent Te and ne localization. For the filterscope, one spatial chord measurement requires three photomultiplier tubes (PMTs) connected to pellicle beam splitters. Multiple, fast visible cameras with narrowband filters are an alternate technique for performing these measurements with superior spatial resolution. Each camera contains millions of pixels; each pixel is analogous to one filterscope PMT. The data can then be inverted and the ratios compared to the CRM to determine 2-dimensional "images" of Te and ne in the plasma. An assessment is made in this paper of the candidate He I emission lines for an imaging technique.
Performance of a plasma fluid code on the Intel parallel computers
Lynch, V.E.; Carreras, B.A.; Drake, J.B.; Leboeuf, J.N.; Liewer, P.
1992-01-01
One approach to improving the real-time efficiency of plasma turbulence calculations is to use a parallel algorithm. A parallel algorithm for plasma turbulence calculations was tested on the Intel iPSC/860 hypercube and the Touchtone Delta machine. Using the 128 processors of the Intel iPSC/860 hypercube, a factor of 5 improvement over a single-processor CRAY-2 is obtained. For the Touchtone Delta machine, the corresponding improvement factor is 16. For plasma edge turbulence calculations, an extrapolation of the present results to the Intel σ machine gives an improvement factor close to 64 over the single-processor CRAY-2
Performance of a plasma fluid code on the Intel parallel computers
Lynch, V.E.; Carreras, B.A.; Drake, J.B.; Leboeuf, J.N.; Liewer, P.
1992-01-01
One approach to improving the real-time efficiency of plasma turbulence calculations is to use a parallel algorithm. A parallel algorithm for plasma turbulence calculations was tested on the Intel iPSC/860 hypercube and the Touchtone Delta machine. Using the 128 processors of the Intel iPSC/860 hypercube, a factor of 5 improvement over a single-processor CRAY-2 is obtained. For the Touchtone Delta machine, the corresponding improvement factor is 16. For plasma edge turbulence calculations, an extrapolation of the present results to the Intel (sigma) machine gives an improvement factor close to 64 over the single-processor CRAY-2. 12 refs
Performance of a plasma fluid code on the Intel parallel computers
Lynch, V. E.; Carreras, B. A.; Drake, J. B.; Leboeuf, J. N.; Liewer, P.
1992-01-01
One approach to improving the real-time efficiency of plasma turbulence calculations is to use a parallel algorithm. A parallel algorithm for plasma turbulence calculations was tested on the Intel iPSC/860 hypercube and the Touchtone Delta machine. Using the 128 processors of the Intel iPSC/860 hypercube, a factor of 5 improvement over a single-processor CRAY-2 is obtained. For the Touchtone Delta machine, the corresponding improvement factor is 16. For plasma edge turbulence calculations, an extrapolation of the present results to the Intel (sigma) machine gives an improvement factor close to 64 over the single-processor CRAY-2.
Green, David L.; Berry, Lee A.; Simpson, Adam B.; Younkin, Timothy R.
2018-04-01
We present the KINETIC-J code, a computational kernel for evaluating the linearized Vlasov equation with application to calculating the kinetic plasma response (current) to an applied time harmonic wave electric field. This code addresses the need for a configuration space evaluation of the plasma current to enable kinetic full-wave solvers for waves in hot plasmas to move beyond the limitations of the traditional Fourier spectral methods. We benchmark the kernel via comparison with the standard k →-space forms of the hot plasma conductivity tensor.
Bai, Feng; Johnson, Jennifer; Wang, Fan; Yang, Lei; Broniscer, Alberto; Stewart, Clinton F
2011-09-01
A sensitive and precise LC-ESI-MS/MS method for the determination of vandetanib (ZD6474) in human plasma and cerebrospinal fluid (CSF) using [(13)C,d(3)]-ZD6474 as an internal standard (ISTD) was developed and validated. Sample preparation consisted of a simple liquid-liquid extraction with tert-butyl methyl ether containing 0.1% or 0.5% ammonium hydroxide. ZD6474 and ISTD were separated on a Kinetex C18 column (2.6 μm, 50 mm × 2.1 mm) at ambient temperature with an isocratic mobile phase (acetonitrile/10mM ammonium formate=50/50, v/v, at pH 5.0) delivered at 0.11 mL/min. The retention time of both compounds was at 1.60 min in a runtime of three min. Detection was achieved by an API-3200 LC-MS/MS system, monitoring m/z 475.1/112.1 and m/z 479.1/116.2 for vandetanib and ISTD, respectively. The method was linear in the range of 0.25-50 ng/mL (R(2) ≥ 0.990) for the CSF curve and from 1.0 to 3000 ng/mL (R(2) ≥ 0.992) for the plasma curve. The mean recovery for vandetanib was 80%. Within-day and between-day precisions were ≤ 8.8% and ≤ 5.9% for CSF and plasma, respectively. Within-day and between-day accuracies ranged from 95.0 to 98.5% for CSF, and from 104.0 to 108.5% for plasma. Analysis of plasma from six different sources showed no matrix effect for vandetanib (MF=0.98, %CV ≤ 4.97, n=6). This method was successfully applied to the analysis of pharmacokinetic samples from children with brain tumors treated with oral vandetanib. Copyright © 2011 Elsevier B.V. All rights reserved.
Kerbel, G.D.
1981-01-20
A study is made of a scale model in three dimensions of a guiding center plasma within the purview of gyroelastic (also known as finite gyroradius-near theta pinch) magnetohydrodynamics. The (nonlinear) system sustains a particular symmetry called isorrhopy which permits the decoupling of fluid modes from drift modes. Isorrhopic equilibria are analyzed within the framework of geometrical optics resulting in (local) dispersion relations and ray constants. A general scheme is developed to evolve an arbitrary linear perturbation of a screwpinch equilibrium as an invertible integral transform (over the complete set of generalized eigenfunctions defined naturally by the equilibrium). Details of the structure of the function space and the associated spectra are elucidated. Features of the (global) dispersion relation owing to the presence of gyroelastic stabilization are revealed. An energy principle is developed to study the stability of the tubular screwpinch.
Kerbel, G.D.
1981-01-01
A study is made of a scale model in three dimensions of a guiding center plasma within the purview of gyroelastic (also known as finite gyroradius-near theta pinch) magnetohydrodynamics. The (nonlinear) system sustains a particular symmetry called isorrhopy which permits the decoupling of fluid modes from drift modes. Isorrhopic equilibria are analyzed within the framework of geometrical optics resulting in (local) dispersion relations and ray constants. A general scheme is developed to evolve an arbitrary linear perturbation of a screwpinch equilibrium as an invertible integral transform (over the complete set of generalized eigenfunctions defined naturally by the equilibrium). Details of the structure of the function space and the associated spectra are elucidated. Features of the (global) dispersion relation owing to the presence of gyroelastic stabilization are revealed. An energy principle is developed to study the stability of the tubular screwpinch
Analysis of plasma instabilities and verification of the BOUT code for the Large Plasma Device
Popovich, P.; Carter, T. A.; Friedman, B.; Umansky, M. V.
2010-01-01
The properties of linear instabilities in the Large Plasma Device [W. Gekelman et al., Rev. Sci. Instrum. 62, 2875 (1991)] are studied both through analytic calculations and solving numerically a system of linearized collisional plasma fluid equations using the three-dimensional fluid code BOUT[M. Umansky et al., Contrib. Plasma Phys. 180, 887 (2009)], which has been successfully modified to treat cylindrical geometry. Instability drive from plasma pressure gradients and flows is considered, focusing on resistive drift waves and the Kelvin-Helmholtz and rotational interchange instabilities. A general linear dispersion relation for partially ionized collisional plasmas including these modes is derived and analyzed. For Large Plasma Device relevant profiles including strongly driven flows, it is found that all three modes can have comparable growth rates and frequencies. Detailed comparison with solutions of the analytic dispersion relation demonstrates that BOUT accurately reproduces all characteristics of linear modes in this system.
Sutherland, D. A.; Hansen, C. J.; Jarboe, T. R.
2017-10-01
A self-consistent, two-fluid (plasma-neutral) dynamic neutral model has been implemented into the 3-D, Extended-MHD code PSI-Tet. A monatomic, hydrogenic neutral fluid reacts with a plasma fluid through elastic scattering collisions and three inelastic collision reactions: electron-impact ionization, radiative recombination, and resonant charge-exchange. Density, momentum, and energy are evolved for both the plasma and neutral species. The implemented plasma-neutral model in PSI-Tet is being used to simulate decaying spheromak configurations in the HIT-SI experimental geometry, which is being compare to two-photon absorption laser induced fluorescence measurements (TALIF) made on the HIT-SI3 experiment. TALIF is used to measure the absolute density and temperature of monatomic deuterium atoms. Neutral densities on the order of 1015 m-3 and neutral temperatures between 0.6-1.7 eV were measured towards the end of decay of spheromak configurations with initial toroidal currents between 10-12 kA. Validation results between TALIF measurements and PSI-Tet simulations with the implemented dynamic neutral model will be presented. Additionally, preliminary dynamic neutral simulations of the HIT-SI/HIT-SI3 spheromak plasmas sustained with inductive helicity injection will be presented. Lastly, potential benefits of an expansion of the two-fluid model into a multi-fluid model that includes multiple neutral species and tracking of charge states will be discussed.
Yousfi, M.; Eichwald, O.; Merbahi, N.; Jomaa, N.
2012-08-01
This work is devoted to fluid modeling based on experimental investigations of a classical setup of a low-temperature plasma jet. The latter is generated at atmospheric pressure using a quartz tube of small diameter crossed by helium gas flow and surrounded by an electrode system powered by a mono-polar high-voltage pulse. The streamer-like behavior of the fast plasma bullets or ionization waves launched in ambient air for every high-voltage pulse, already emphasized in the literature from experimental or analytical considerations or recent preliminary fluid models, is confirmed by a numerical one-moment fluid model for the simulation of the ionization wave dynamics. The dominant interactions between electron and the main ions present in He-air mixtures with their associated basic data are taken into account. The gradual dilution of helium in air outside the tube along the axis is also considered using a gas hydrodynamics model based on the Navier-Stokes equation assuming a laminar flow. Due to the low magnitude of the reduced electric field E/N (not exceeding 15 Td), it is first shown that consideration of the stepwise ionization of helium metastables is required to reach the critical size of the electron avalanches in order to initiate the formation of ionization waves. It is also shown that a gas pre-ionization ahead of the wave front of about 109 cm-3 (coming from Penning ionization without considering the gas photo-ionization) is required for the propagation. Furthermore, the second ionization wave experimentally observed during the falling time of the voltage pulse, between the powered electrode and the tube exit, is correlated with the electric field increase inside the ionized channel in the whole region between the electrode and the tube exit. The propagation velocity and the distance traveled by the front of the ionization wave outside the tube in the downstream side are consistent with the present experimental measurements. In comparison with the
Cluster explosion investigated by linearly chirped spectral scattering of an expanding plasma sphere
Liu Jiansheng; Wang Cheng; Liu Bingchen; Shuai Bin; Wang Wentao; Cai Yi; Li Hongyu; Ni Guoquan; Li Ruxin; Xu Zhizhan
2006-01-01
Femtosecond explosive processes of argon clusters irradiated by linearly chirped ultraintense laser pulses have been investigated by 90 deg. side spectral scattering. The spectral redshift and blueshift, which correlate with the cluster explosion processes have been measured for negatively and positively chirped driving laser pulses, respectively. The evolution of the heated-cluster polarizability indicates that the core of the cluster is shielded from the laser field in the beginning of the explosion and enhanced scattering occurs after the fast explosion initiates. Evidence of resonant heating is found from the coincidence of enhanced scattering with enhanced absorption measured using the transmitted spectra. Anomalously large-size clusters with very low gas density have been observed in this way and can be used as clean and important cluster targets
Steinbrecher, Gyoergy; Weyssow, B.
2004-01-01
The extreme heavy tail and the power-law decay of the turbulent flux correlation observed in hot magnetically confined plasmas are modeled by a system of coupled Langevin equations describing a continuous time linear randomly amplified stochastic process where the amplification factor is driven by a superposition of colored noises which, in a suitable limit, generate a fractional Brownian motion. An exact analytical formula for the power-law tail exponent β is derived. The extremely small value of the heavy tail exponent and the power-law distribution of laminar times also found experimentally are obtained, in a robust manner, for a wide range of input values, as a consequence of the (asymptotic) self-similarity property of the noise spectrum. As a by-product, a new representation of the persistent fractional Brownian motion is obtained
Measurement of monoterpenes and sesquiterpenes in serum, plasma, and rumen fluid from sheep
Studies involving the consumption, metabolism, and elimination of terpenes by small ruminants consuming terpene-laden shrubs as well as those exploring the potential for natural products as rumen modifiers could benefit from a procedure that measures terpenes in both blood and rumen fluid and that i...
Spiral waves in driven dusty plasma medium: Generalized hydrodynamic fluid description
Kumar, Sandeep; Patel, Bhavesh; Das, Amita
2018-04-01
Spiral waves are observed in many natural phenomena. They have been extensively represented by the mathematical FitzHugh-Nagumo model [Barkley et al., Phys. Rev. A 42, 2489 (1990)] of excitable media. Also, in incompressible fluid simulations, the excitation of thermal spiral waves has been reported by Li et al. [Phys. of Fluids 22, 011701 (2010)]. In the present paper, the spatiotemporal development of spiral waves in the context of weak and strong coupling limits has been shown. While the weakly coupled medium has been represented by a simple fluid description, for strong coupling, a generalized visco-elastic fluid description has been employed. The medium has been driven by an external force in the form of a rotating electric field. It is shown that when the amplitude of force is small, the density perturbations in the medium are also small. In this case, the excitations do not develop as a spiral wave. Only when the amplitude of force is high so as to drive the density perturbations to nonlinear amplitudes does the spiral density wave formation occurs. The role of the forcing frequency and the effect of strong coupling and the sound velocity of medium in the formation and evolution of spiral waves have been investigated in detail.
Zeitler, Benno Michael Georg
2017-01-01
Laser Wake field Acceleration (LWFA) has the potential to become the next-generation acceleration technique for electrons. In particular, the large field gradients provided by these plasma-based accelerators are an appealing property, promising a significant reduction of size for future machines and user facilities. Despite the unique advantages of these sources, however, as of today, the produced electron bunches cannot yet compete in all beam quality criteria compared to conventional acceleration methods. Especially the stability in terms of beam pointing and energy gain, as well as a comparatively large energy spread of LWFA electron bunches require further advancement for their applicability. The accelerated particles are typically trapped from within the plasma which is used to create the large field gradients in the wake of a high-power laser. From this results a lack of control and access to observing the actual electron injection - and, consequently, a lack of experimental verification. To tackle this problem, the injection of external electrons into a plasma wakefield seems promising. In this case, the initial beam parameters are known, so that a back-calculation and reconstruction of the wakefield structure are feasible. Such an experiment is planned at the Relativistic Electron Gun for Atomic Exploration (REGAE). REGAE, which is located at DESY in Hamburg, is a small linear accelerator offering unique beam parameters compatible with the requirements of the planned experiment. The observations and results gained from such an external injection are expected to improve the beam quality and stability of internal injection variants, due to the broadened understanding of the underlying plasma dynamics. Furthermore, an external injection will always be required for so-called staging of multiple LWFA-driven cavities. Also, the demonstration of a suchlike merging of conventional and plasma accelerators gives rise to novel hybrid accelerators, where the matured
Zeitler, Benno Michael Georg [Hamburg Univ. (Germany). Fakultaet fuer Mathematik, Informatik und Naturwissenschaften
2017-01-15
Laser Wake field Acceleration (LWFA) has the potential to become the next-generation acceleration technique for electrons. In particular, the large field gradients provided by these plasma-based accelerators are an appealing property, promising a significant reduction of size for future machines and user facilities. Despite the unique advantages of these sources, however, as of today, the produced electron bunches cannot yet compete in all beam quality criteria compared to conventional acceleration methods. Especially the stability in terms of beam pointing and energy gain, as well as a comparatively large energy spread of LWFA electron bunches require further advancement for their applicability. The accelerated particles are typically trapped from within the plasma which is used to create the large field gradients in the wake of a high-power laser. From this results a lack of control and access to observing the actual electron injection - and, consequently, a lack of experimental verification. To tackle this problem, the injection of external electrons into a plasma wakefield seems promising. In this case, the initial beam parameters are known, so that a back-calculation and reconstruction of the wakefield structure are feasible. Such an experiment is planned at the Relativistic Electron Gun for Atomic Exploration (REGAE). REGAE, which is located at DESY in Hamburg, is a small linear accelerator offering unique beam parameters compatible with the requirements of the planned experiment. The observations and results gained from such an external injection are expected to improve the beam quality and stability of internal injection variants, due to the broadened understanding of the underlying plasma dynamics. Furthermore, an external injection will always be required for so-called staging of multiple LWFA-driven cavities. Also, the demonstration of a suchlike merging of conventional and plasma accelerators gives rise to novel hybrid accelerators, where the matured
Subhash, P V; Madhavan, S; Chaturvedi, S
2008-01-01
Two-dimensional (2D) magneto-hydrodynamic (MHD) liner-on-plasma computations have been performed to study the growth of instabilities in a magnetized target fusion system involving the cylindrical compression of an inverse Z-pinch target plasma by a metallic liner. The growth of modes in the plasma can be divided into two phases. During the first phase, the plasma continues to be Kadomtsev stable. The dominant mode in the liner instability is imposed upon the plasma in the form of a growing perturbation. This mode further transfers part of its energy to its harmonics. During the second phase, however, non-uniform implosion of the liner leads to axial variations in plasma quantities near the liner-plasma interface, such that certain regions of the plasma locally violate the Kadomtsev criteria. Further growth ofthe plasma modes is then due to plasma instability. The above numerical study has been complemented with a linear stability analysis for the plasma, the boundary conditions for this analysis being obtained from the liner-on-plasma simulation. The stability of axisymmetric modes in the first phase is found to satisfy the Kadomtsev condition Q 0 1 modes, using equilibrium profiles from the 2D MHD study, shows that their growth rates can exceed those for m=0 by as much as an order of magnitude
Xin Zhang
2014-01-01
Full Text Available Vitamin D-binding protein (DBP is the main transport protein of vitamin D and plays an important role in the immune system and host defenses. The purpose of this study was to measure DBP levels in plasma and gingival crevicular fluid (GCF of patients with generalized aggressive periodontitis (GAgP, in comparison to healthy controls, with the goal of elucidating the relationship between DBP and GAgP. Fifty-nine GAgP patients and 58 healthy controls were recruited for the study; clinical parameters of probing depths (PD, bleeding index, and attachment loss (AL were recorded. DBP levels were measured by enzyme-linked immunosorbent assay. From the results, GAgP patients had higher plasma DBP concentrations (P<0.001 but lower GCF DBP concentrations (P<0.001 than healthy controls. In GAgP group, after controlling the potential confounders of age, gender, smoking status, and BMI index, GCF DBP concentrations correlated negatively with PD (P<0.001 and AL (P=0.009. Within the limits of the study, we concluded that decreased GCF DBP level and increased plasma DBP level are associated with periodontitis.
Non-LTE modeling of the radiative properties of high-Z plasma using linear response methodology
Foord, Mark; Harte, Judy; Scott, Howard
2017-10-01
Non-local thermodynamic equilibrium (NLTE) atomic processes play a key role in the radiation flow and energetics in highly ionized high temperature plasma encountered in inertial confinement fusion (ICF) and astrophysical applications. Modeling complex high-Z atomic systems, such as gold used in ICF hohlraums, is particularly challenging given the complexity and intractable number of atomic states involved. Practical considerations, i.e. speed and memory, in large radiation-hydrodynamic simulations further limit model complexity. We present here a methodology for utilizing tabulated NLTE radiative and EOS properties for use in our radiation-hydrodynamic codes. This approach uses tabulated data, previously calculated with complex atomic models, modified to include a general non-Planckian radiation field using a linear response methodology. This approach extends near-LTE response method to conditions far from LTE. Comparisons of this tabular method with in-line NLTE simulations of a laser heated 1-D hohlraum will be presented, which show good agreement in the time-evolution of the plasma conditions. This work was performed under the auspices of the U.S. Dept. of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.
M. Farooq
Full Text Available This article studies MHD double stratified stagnation point flow of Carreau fluid towards a non linear stretchable surface with radiation. Features of heat and mass transfer are evaluated by using convective boundary conditions. Resulting nonlinear problems are solved and studied for the velocity, temperature and concentration fields. Heat and mass transfer rates in addition to skin friction are discussed. Besides this for the verification of the present findings, the results of presented analysis have been compared with the available works in particular situations and reasonable agreement is noted. Keywords: Convective boundary condition, Thermal radiation, Double stratification, Stagnation point flow
Derivation of the one component plasma fluid equation of state in strong coupling
DeWitt, H.E.; Rosenfeld, Y.
1979-01-01
A variational calculation of the one component plasma energy using the hard sphere Percus-Yevick g(r) and the virial entropy gives U/NkT = a GAMMA + b GAMMAsup(1/4) + c + d/ GAMMAsup(1/4) + ... in agreement with the empirical fit to Monte Carlo data. (orig.)
Progranulin Levels in Plasma and Cerebrospinal Fluid in Granulin Mutation Carriers
L.H.H. Meeter (Lieke H.H.); Patzke, H. (Holger); Loewen, G. (Gordon); E.G.P. Dopper (Elise); Y. Pijnenburg (Yolande); A.S. Thornton (Andrew); J.C. van Swieten (John)
2016-01-01
textabstractBackground: Pathogenic mutations in the granulin gene (GRN) are causative in 5-10% of patients with frontotemporal dementia (FTD), mostly leading to reduced progranulin protein (PGRN) levels. Upcoming therapeutic trials focus on enhancing PGRN levels. Methods: Fluctuations in plasma PGRN
The development of fluid codes for the laser compression of plasma
Nicholas, D.J.
1982-08-01
Notes are given on the construction and use of simulation codes in plasma physics requiring only a limited background knowledge in numerical analysis and finite-difference techniques. The development of a 1-D Eulerian codes to source form is followed as an example. (U.K.)
Sonia Molina-Pinelo
2012-01-01
Full Text Available The identification of new less invasive biomarkers is necessary to improve the detection and prognostic outcome of respiratory pathological processes. The measurement of miRNA expression through less invasive techniques such as plasma and serum have been suggested to analysis of several lung malignancies including lung cancer. These studies are assuming a common deregulated miRNA expression both in blood and lung tissue. The present study aimed to obtain miRNA representative signatures both in plasma and bronchoalveolar cell fraction that could serve as biomarker in respiratory diseases. Ten patients were evaluated to assess the expression levels of 381 miRNAs. We found that around 50% miRNAs were no detected in both plasma and bronchoalveolar cell fraction and only 20% of miRNAs showed similar expression in both samples. These results show a lack of association of miRNA signatures between plasma and bronchoalveolar cytology in the same patient. The profiles are not comparable; however, there is a similarity in the relative expression in a very small subset of miRNAs (miR-17, miR-19b, miR-195 and miR-20b between both biological samples in all patients. This finding supports that the miRNAs profiles obtained from different biological samples have to be carefully validated to link with respiratory diseases.
Validation of Numerical Two-Fluid and Kinetic Plasma Models. Final Report
Barnes, Daniel
2011-01-01
This was a four year grant commencing October 1, 2003 and finishing September 30, 2007. The funding was primarily used to support the work of the Principal Investigator, who collaborated with Profs. Scott Parker and John Cary at U. Colorado, and with two students, N. Xiang and J. Cheng also of U. Colorado. The technical accomplishments of this grant can be found in the publications listed in the final Section here. The main accomplishments of the grant work were: (1) Development and implementation of time-implicit two-fluid simulation methods in collaboration with the NIMROD team; and (2) Development and testing of a new time-implicit delta-f, energy-conserving method The basic two-fluid method, with many improvements is used in present NIMROD calculations. The energy-conserving delta-f method is under continuing development under contract between Coronado Consulting, a New Mexico sole proprietorship and the Oak Ridge National Laboratory.
Tittarelli, Roberta; Pichini, Simona; Pedersen, Daniel S; Pacifici, Roberta; Moresco, Monica; Pizza, Fabio; Busardò, Francesco Paolo; Plazzi, Giuseppe
2017-05-01
Sodium oxybate (Xyrem ® ), the sodium salt of γ- hydroxybutyric acid (GHB), is a first-line treatment of the symptoms induced by type 1 narcolepsy (NT1) and it is highly effective in improving sleep architecture, decreasing excessive daytime sleepiness and the frequency of cataplexy attacks. Using an ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) validated method, GHB was determined together with its glucuronide (GHB-gluc), in plasma and cerebrospinal fluid (CSF) samples of NT1 patients under sodium oxybate treatment. To characterize the plasma pharmacokinetics of GHB, three subjects with NT1 were administered at time 0 and 4h with 1.25, 1.5 and 3.55g Xyrem ® , respectively and had their blood samples collected at 7 time points throughout an 8-h session. CSF specimens, collected for orexin A measurement from the same three subjects 6h after their second administration, were also tested. The results obtained suggested that GHB plasma values increased disproportionally with the rising doses, (C max0-4 : 12.53, 32.95 and 69.62μg/mL; C max4-8 : 44.93, 75.03 and 111.93μg/mL for total Xyrem ® dose of 2.5, 3 and 7g respectively) indicating non-linear dose-response. GHB-Gluc was present only in traces in all plasma samples from treated patients, not changing with increasing Xyrem ® doses. GHB values of 5.62, 6.10 and 17.74μg/mL for 2, 3 and 7g Xyrem ® were found in CSF with a significant difference from control values. GHB-Gluc was found in negligible concentrations with no differences to those of control individuals. In conclusion this simple and fast UHPLC-MS/MS method proved useful for pharmacokinetic studies and therapeutic drug monitoring of GHB in narcoleptic patients treated with sodium oxybate. Copyright © 2017 Elsevier B.V. All rights reserved.
Sílvia Regina Cavani Jorge Santos
2012-10-01
Full Text Available Objectives: To determine whether amphotericin B (AmB and fluconazole cross the blood-brain barrier in a similar manner in patients with HIV-associated cryptococcal meningitis based on the cerebrospinal fluid (CSF/plasma drug ratio through a comparative study. Methods: This prospective, open-label clinical protocol included 21 male and female patients, 28-55 years of age. The patients were infected with HIV (CD4 50-200 cells/mL and cryptococcal meningitis and were receiving AmB (1 mg/kg daily, infusion of four hours; 6-10 weeks and fluconazole (400 mg 12 qh; until CSF was negative for fungal growth. The patients were informed in detail about all procedures to be performed in the hospital, including blood and CSF sample collection, if required. The study protocol was approved by the hospital’s ethical committee. Plasma samples were obtained by centrifugation at 2800 g for 30 min, and CSF samples were collected by the physician to relieve symptoms caused by intracranial hypertension. The drug concentrations of both antifungal agents were determined in the biological samples using HPLC. Results: The mean drug plasma: CSF concentrations were 2.30:0.3 μg/mL and 31.7:19.4 μg/mL for AmB and fluconazole, respectively. The CSF:plasma ratios were 0.20 (AmB and 0.67 (fluconazole. Conclusions: Unlike fluconazole, the conventional AmB formulation did not reach the optimum CSF drug concentration. However, a high-dose regimen of fluconazole contributes to the outcome of HIV inpatients with severe cryptococcal meningitis.
Weitzner, H.
1990-06-01
This paper discusses the following topics: MHD plasma activity: equilibrium, stability and transport; statistical analysis; transport studies; edge physics studies; wave propagation analysis; basic plasma physics and fluid dynamics; space plasma; and numerical methods
Thode, L.E.
1978-09-01
A 36-month program to study the linear relativistic electron beam-plasma interaction is proposed. This program is part of a joint proposal between the Physics International Company (PI) and Los Alamos Scientific Laboratory (LASL) that combines the advanced electron beam generator technology at PI with the highly developed computer simulation technology at LASL. The proposed LASL program includes direct support for 1- and 3-m beam-plasma interaction experiments planned at PI and development of theory relevant for design of a 10-m proof-of-principle electron beam-driven linear solenoidal reactor
Optics and Fluid Dynamics Department annual progress report for 2000
Hanson, Steen Grüner; Johansen, Per Michael; Lynov, Jens-Peter
2001-01-01
The Optics and Fluid Dynamics Department performs basic and applied research within three scientific programmes: (1) optical materials, (2) optical diagnostics and information processing and (3) plasma and fluid dynamics. The department has corecompetences in: optical sensors, optical materials......, optical storage, biooptics, numerical modelling and information processing, non-linear dynamics and fusion plasma physics. The research is supported by several EU programmes, including EURATOM, by Danishresearch councils and by industry. A summary of the activities in 2000 is presented....
Optics and Fluid Dynamics Department annual progress report for 2002
Bindslev, H.; Hanson, Steen Grüner; Lynov, Jens-Peter
2003-01-01
The Optics and Fluid Dynamics Department performs basic and applied research within three scientific programmes: (1) laser systems and optical materials (2) optical diagnostics and information processing and (3) plasma and fluid dynamics. The departmenthas core competences in: optical sensors......, optical materials, optical storage, biophotonics, numerical modelling and information processing, non-linear dynamics and fusion plasma physics. The research is supported by several EU programmes, includingEURATOM, by Danish research councils and by industry. A summary of the activities in 2002...
Obradović Dragana
2012-01-01
Full Text Available Background/Aim. Multiple sclerosis (MS is an immunemediated central nervous system disease characterized by inflammation, demyelination and axonal degeneration. Cytokines are proven mediators of immunological process in MS. The aim of this study was to investigate whether there is a difference in the production of the tumor necrosis factor alpha (TNF-alpha and interleukin-4 (IL-4 in cerebrospinal fluid (CSF and plasma in the MS patients and the controls (other neurological non-inflammatory diseases and to determine a possible difference in these cytokines in plasma and CSF in different clinical forms of MS. Methods. This study involved 60 consecutive MS patients - 48 patients with relapsing-remitting MS (RRMS and 12 patients with secondary progressive MS (SPMS. The control group consisted of 20, age and sex matched, nonimmunological, neurological patients. According to the clinical presentation of MS at the time of this investigation, 34 (56.7% patients had relapse (RRMS, 14 (23.3% were in remission (RRMS, while the rest of the patients, 12 (20.0%, were SPMS. TNF-alpha and IL-4 concentrations were measured in the same time in CSF and plasma in the MS patients and the controls. Extended disability status score (EDSS, albumin ratio and IgG index were determined in all MS patients. Results. The MS patients had significantly higher CSF and plasma levels of TNF-alpha than the controls (p < 0.001 for both samples. IL-4 CSF levels were significantly lower in the MS patients than in the controls (p < 0.001, however plasma levels were similar. The patients in relapse (RRMS and with progressive disease (SPMS had higher concentrations of CSF TNF-alpha levels than the patients in remission (p < 0.001. IL-4 CSF levels in relapse (RRMS and SPMS groups were lower than in the patients in remission. The patients in remission had an unmeasurable plasma TNF-alpha level and the patients with SPMS had significantly lower IL-4 levels in plasma than the patients in
Srivastava, Abhishek; Waterhouse, David; Ardrey, Alison; Ward, Stephen A.
2012-01-01
A highly sensitive and rapid liquid chromatography tandem mass spectrometry (LC–MS/MS) method has been developed to measure the levels of the antitubercular drug rifampicin (RIF) in human plasma and cerebrospinal fluid (CSF). The analyte and internal standard (IS) were isolated from plasma and CSF by a simple organic solvent based precipitation of proteins followed by centrifugation. Detection was carried out by electrospray positive ionization mass spectrometry in the multiple-reaction monit...
Colombant, Denis; Manheimer, Wallace
2010-01-01
Flux limitation and preheat are important processes in electron transport occurring in laser produced plasmas. The proper calculation of both of these has been a subject receiving much attention over the entire lifetime of the laser fusion project. Where nonlocal transport (instead of simple single flux limit) has been modeled, it has always been with what we denote the equivalent diffusion solution, namely treating the transport as only a diffusion process. We introduce here a new approach called the nonlocal source solution and show it is numerically viable for laser produced plasmas. It turns out that the equivalent diffusion solution generally underestimates preheat. Furthermore, the advance of the temperature front, and especially the preheat, can be held up by artificial 'thermal barriers'. The nonlocal source method of solution, on the other hand more accurately describes preheat and can stably calculate the solution for the temperature even if the heat flux is up the gradient.
Vie, M.-T.
1973-01-01
By the labelling of a plasma substitute prepared from gelatine, MFG or modified fluid gelatine, it was possible to establish certain facts concerning the kinetics of MFG and its action on the cells of the reticulo-endothelial system. Iodine labelling proved sufficiently reliable to allow the pharmakokinetic exploration of the product by a method which, being relatively simple to use, offers good reproducibility of results. Various tests on the strength of the iodine protein bond showed the stability of the entire protein molecule. A study of the metabolism revealed that the MFG in question behaves towards the organism not as a pure substance but as a mixture of two molecular species of different mass. The experimental results concerning the influence of MFG on the reticulo-endothelial system showed that the phagocyte function is only modified if there is competition between the phagocyted molecule and the MFG [fr
Liu Chenglong; Xin Yunchang; Tian Xiubo; Chu, Paul K.
2007-01-01
Due to the good biocompatibility and tensile yield strength, magnesium alloys are promising in degradable prosthetic implants. The objective of this study is to investigate the corrosion behavior of surgical AZ91 magnesium alloy treated by aluminum, zirconium, and titanium plasma immersion ion implantation and deposition (PIII and D) at 10 kV in artificial physiological fluids. The surface layers show a characteristic intermixed layer and the outer surface are mainly composed of aluminum, zirconium or titanium oxide with a lesser amount of magnesium oxide. Comparing the three sets of samples, aluminum PIII and D significantly shifts the open circuit potential (OCP) to a more positive potential and improves the corrosion resistance at OCP
Joseph, Ilon [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
2014-05-27
Jacobian-free Newton-Krylov (JFNK) algorithms are a potentially powerful class of methods for solving the problem of coupling codes that address dfferent physics models. As communication capability between individual submodules varies, different choices of coupling algorithms are required. The more communication that is available, the more possible it becomes to exploit the simple sparsity pattern of the Jacobian, albeit of a large system. The less communication that is available, the more dense the Jacobian matrices become and new types of preconditioners must be sought to efficiently take large time steps. In general, methods that use constrained or reduced subsystems can offer a compromise in complexity. The specific problem of coupling a fluid plasma code to a kinetic neutrals code is discussed as an example.
Two fluid plasmas in the vicinity of a Schwarzschild black hole
Buzzi, V.; Hines, K.C.
1992-01-01
The 3+1 split of general relativity has been used to investigate the dispersion relation for certain plasma waves, together with the two stream instability, in the vicinity of a Schwarzschild black hole horizon. In contrast to the special relativistic results, the dispersion relations discussed here contain additional terms involving the gravitational acceleration, a, and the lapse function α. Some of these terms are imaginary and should correspond to gravitational damping effects. 5 refs
Matějčková, J.; Tůma, P.; Samcová, E.; Zemanová, Zdeňka
2007-01-01
Roč. 30, č. 12 (2007), s. 1947-1952 ISSN 1615-9306 R&D Projects: GA ČR(CZ) GA304/04/0972 Grant - others:GA ČR(CZ) GA203/07/0896 Program:GA Institutional research plan: CEZ:AV0Z50110509 Keywords : capillary electrophoresis * microsamples of plasma * uric acid Subject RIV: CE - Biochemistry Impact factor: 2.632, year: 2007
Three-dimensional two-fluid Braginskii simulations of the large plasma device
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.
Application of a two fluid theoretical plasma transport model on current tokamak reactor designs
Ibrahim, E.; Fowler, T.K.
1987-06-01
In this work, the new theoretical transport models to TIBER II design calculations are described and the results are compared with recent experimental data in large tokamaks (TFTR, JET). Tang's method is extended to a two-fluid model treating ions and electrons separately. This allows for different ion and electron temperatures, as in recent low-density experiments in TFTR, and in the TIBER II design itself. The discussion is divided into two parts: (1) Development of the theoretical transport model and (2) calibration against experiments and application to TIBER II
Jordan, T.
1996-01-01
Some aspects concerning the coupling of quasi-stationary electromagnetics and the dynamics of structure and fluid are investigated. The necessary equations are given in a dimensionless form. The dimensionless parameters in these equations are used to evaluate the importance of the different coupling effects. A finite element formulation of the eddy-current damping in solid structures is developed. With this formulation, an existing finite element method (FEM) structural dynamics code is extended and coupled to an FEM eddy-current code. With this program system, the influence of the eddy-current damping on the dynamic loading of the dual coolant blanket during a centered plasma disruption is determined. The analysis proves that only in loosely fixed or soft structures will eddy-current damping considerably reduce the resulting stresses. Additionally, the dynamic behavior of the liquid metal in the blankets' poloidal channels is described with a simple two-dimensional magnetohydrodynamic approach. The analysis of the dimensionless parameters shows that for small-scale experiments, which are designed to model the coupled electromagnetic and structural/fluid dynamic effects in such a blanket, the same magnetic fields must be applied as in the real fusion device. This will be the easiest way to design experiments that produce transferable results. 10 refs., 7 figs
Dagrau, Franck; Coulouvrat, François; Marchiano, Régis; Héron, Nicolas
2008-06-01
Dassault Aviation as a civil aircraft manufacturer is studying the feasibility of a supersonic business jet with the target of an "acceptable" sonic boom at the ground level, and in particular in case of focusing. A sonic boom computational process has been performed, that takes into account meteorological effects and aircraft manoeuvres. Turn manoeuvres and aircraft acceleration create zones of convergence of rays (caustics) which are the place of sound amplification. Therefore two elements have to be evaluated: firstly the geometrical position of the caustics, and secondly the noise level in the neighbourhood of the caustics. The modelling of the sonic boom propagation is based essentially on the assumptions of geometrical acoustics. Ray tracing is obtained according to Fermat's principle as paths that minimise the propagation time between the source (the aircraft) and the receiver. Wave amplitude and time waveform result from the solution of the inviscid Burgers' equation written along each individual ray. The "age variable" measuring the cumulative nonlinear effects is linked to the ray tube area. Caustics are located as the place where the ray tube area vanishes. Since geometrical acoustics does not take into account diffraction effects, it breaks down in the neighbourhood of caustics where it would predict unphysical infinite pressure amplitude. The aim of this study is to describe an original method for computing the focused noise level. The approach involves three main steps that can be summarised as follows. The propagation equation is solved by a forward marching procedure split into three successive steps: linear propagation in a homogeneous medium, linear perturbation due to the weak heterogeneity of the medium, and non-linear effects. The first step is solved using an "exact" angular spectrum algorithm. Parabolic approximation is applied only for the weak perturbation due to the heterogeneities. Finally, non linear effects are performed by solving the
Collisionless kinetic-fluid model of zonal flows in toroidal plasmas
Sugama, H.; Watanabe, T.-H.; Horton, W.
2006-12-01
A novel kinetic-fluid model is presented, which describes collisionless time evolution of zonal flows in tokamaks. In the new zonal-flow closure relations, the parallel heat fluxes are written by the sum of short- and long-time-evolution parts. The former part is given in the dissipative form of the parallel heat diffusion and relates to collisionless damping processes. The latter is derived from the long-time-averaged gyrocenter distribution and plays a major role in describing low-frequency or stationary zonal flows, for which the parallel heat fluxes are expressed in terms of the parallel flow as well as the nonlinear-source and initial-condition terms. It is shown analytically and numerically that, when applied to the zonal flow driven by either ion or electron temperature gradient turbulence, the kinetic-fluid equations including the new closure relations can reproduce the same long-time zonal-flow responses to the initial condition and to the turbulence source as those obtained from the gyrokinetic model. (author)
Kim, H.C.; Yang, S.S.; Lee, J.K.
2003-01-01
In plasma display panels (PDPs), the resonance radiation trapping is one of the important processes. In order to incorporate this effect in a PDP cell, a three-dimensional radiation transport model is self-consistently coupled with a fluid simulation. This model is compared with the conventional trapping factor method in gas mixtures of neon and xenon. It shows the differences in the time evolutions of spatial profile and the total number of resonant excited states, especially in the afterglow. The generation rates of UV light are also compared for the two methods. The visible photon flux reaching the output window from the phosphor layers as well as the total UV photon flux arriving at the phosphor layer from the plasma region are calculated for resonant and nonresonant excited species. From these calculations, the time-averaged spatial profiles of the UV flux on the phosphor layers and the visible photon flux through the output window are obtained. Finally, the diagram of the energy efficiency and the contribution of each UV light are shown
do Nascimento, Kenia Kelly Fiaux; Silva, Kelly P.; Malloy-Diniz, Leandro F.; Butters, Meryl A.; Diniz, Breno S.
2016-01-01
This study aimed to evaluate differences in plasma and cerebrospinal fluid (CSF) levels of Aβ peptides in older adults with late-life depression compared to non-depressed older controls. We conducted a systematic review and meta-analysis of the literature using PubMed, Web of science and Scopus databases with no search limits for publication dates or languages. Two independent reviewers extracted data and assessed quality. Six hundred references were retrieved, and we included 12 studies in the meta-analysis after eligibility screening. Older adults with late-life depression (LLD) had a higher plasma Aβ40:Aβ42 ratio compared to non-depressed participants (SMD= 1.10, CI95% [0.28; 1.96], p=0.01), and marginally significant reduction of CSF Aβ42 levels (SMD= −1.12, CI95% [−2.47; 0.22], p=0.1). The present results evidence that older adults with depression have significant differences in Aβ metabolism, in the same direction observed in individuals with AD. These differences in the Aβ metabolism may help identify a subgroup of subjects with LLD at higher risk of developing AD. PMID:26343592
Chaplin, Vernon H.; Bellan, Paul M.
2015-12-01
A time-dependent two-fluid model has been developed to understand axial variations in the plasma parameters in a very high density (peak ne≳ 5 ×1019 m-3 ) argon inductively coupled discharge in a long 1.1 cm radius tube. The model equations are written in 1D with radial losses to the tube walls accounted for by the inclusion of effective particle and energy sink terms. The ambipolar diffusion equation and electron energy equation are solved to find the electron density ne(z ,t ) and temperature Te(z ,t ) , and the populations of the neutral argon 4s metastable, 4s resonant, and 4p excited state manifolds are calculated to determine the stepwise ionization rate and calculate radiative energy losses. The model has been validated through comparisons with Langmuir probe ion saturation current measurements; close agreement between the simulated and measured axial plasma density profiles and the initial density rise rate at each location was obtained at pA r=30 -60 mTorr . We present detailed results from calculations at 60 mTorr, including the time-dependent electron temperature, excited state populations, and energy budget within and downstream of the radiofrequency antenna.
Ivchenko, Dmitrii; Zhang, Tao; Mariaux, Gilles; Vardelle, Armelle; Goutier, Simon; Itina, Tatiana E.
2018-01-01
Plasma spray physical vapor deposition aims to substantially evaporate powders in order to produce coatings with various microstructures. This is achieved by powder vapor condensation onto the substrate and/or by deposition of fine melted powder particles and nanoclusters. The deposition process typically operates at pressures ranging between 10 and 200 Pa. In addition to the experimental works, numerical simulations are performed to better understand the process and optimize the experimental conditions. However, the combination of high temperatures and low pressure with shock waves initiated by supersonic expansion of the hot gas in the low-pressure medium makes doubtful the applicability of the continuum approach for the simulation of such a process. This work investigates (1) effects of the pressure dependence of thermodynamic and transport properties on computational fluid dynamics (CFD) predictions and (2) the validity of the continuum approach for thermal plasma flow simulation under very low-pressure conditions. The study compares the flow fields predicted with a continuum approach using CFD software with those obtained by a kinetic-based approach using a direct simulation Monte Carlo method (DSMC). It also shows how the presence of high gradients can contribute to prediction errors for typical PS-PVD conditions.
Haines, M.G.; Bond, D.J.; Chuaqui, H.H.
1983-01-01
The paper reports experimental and theoretical contributions to the understanding of non-linear heat flow and the phenomenon of jet-like filamentary structures in inertial-confinement fusion. When lateral heat flow is minimized, through applying more carefully a radially symmetric irradiation at 1.05 and 0.53 μm on a spherical target, it is found that a heat flux in excess of 10% of the free-streaming limit is consistent with simulations and experimental measurements with particle and X-ray diagnostics. A similar result has been found in a scaled experiment in a plasma of electron density 4x10 16 cm - 3 when the condition Tsub(e) approx.=Tsub(i) is satisfied. These results are in marked contrast to earlier assertions, mainly from plane-target measurements, that the flux limiter is 3%, but in agreement with theoretical calculations of steady non-linear heat flow using a discrete-ordinate method. Thus, no anomalous inhibition of heat flow is found, consistent with theoretical predictions that ion-acoustic turbulence is of no importance in dense (n>=10 21 cm - 3 , T approx.= 1 keV) plasmas. However, in the low-density scaled experiment, under conditions where Tsub(e)>>Tsub(i) is found that ion-acoustic turbulence is present, and the flux limiter is 4%. By using shadowgraphic and schlieren techniques with an optical diagnostic probe, fine-scale jet-like structures have been observed on a scale-length of approx. 10 μm on spherical targets. They occur even outside the laser-irradiated region, and are not connected with irregularities in the laser beam; they are more pronounced with higher-Z materials and with shorter-wavelength lasers, and have megagauss magnetic fields associated with them. Electromagnetic instabilities driven by heat flow are the probable cause of the jets, and of the three known modes the thermal instability, enhanced by radiation loss, agrees more closely with the experiments than the Weibel and thermomagnetic modes, since the latter only occur
Gotfried, Mark H; Horn, Karolyn; Garrity-Ryan, Lynne; Villano, Stephen; Tzanis, Evan; Chitra, Surya; Manley, Amy; Tanaka, S Ken; Rodvold, Keith A
2017-09-01
The steady-state concentrations of omadacycline and tigecycline in the plasma, epithelial lining fluid (ELF), and alveolar cells (AC) of 58 healthy adult subjects were obtained. Subjects were administered either omadacycline at 100 mg intravenously (i.v.) every 12 h for two doses followed by 100 mg i.v. every 24 h for three doses or tigecycline at an initial dose of 100 mg i.v. followed by 50 mg i.v. every 12 h for six doses. A bronchoscopy and bronchoalveolar lavage were performed once in each subject following the start of the fifth dose of omadacycline at 0.5, 1, 2, 4, 8, 12, or 24 h and after the start of the seventh dose of tigecycline at 2, 4, 6, or 12 h. The value of the area under the concentration-time curve (AUC) from time zero to 24 h postdosing (AUC 0-24 ) (based on mean concentrations) in ELF and the ratio of the ELF to total plasma omadacycline concentration based on AUC 0-24 values were 17.23 mg · h/liter and 1.47, respectively. The AUC 0-24 value in AC was 302.46 mg · h/liter, and the ratio of the AC to total plasma omadacycline concentration was 25.8. In comparison, the values of the AUC from time zero to 12 h postdosing (AUC 0-12 ) based on the mean concentrations of tigecycline in ELF and AC were 3.16 and 38.50 mg · h/liter, respectively. The ratio of the ELF and AC to total plasma concentrations of tigecycline based on AUC 0-12 values were 1.71 and 20.8, respectively. The pharmacokinetic advantages of higher and sustained concentrations of omadacycline compared to those of tigecycline in plasma, ELF, and AC suggest that omadacycline is a promising antibacterial agent for the treatment of lower respiratory tract bacterial infections caused by susceptible pathogens. Copyright © 2017 Gotfried et al.
Fluid simulation for two laser beams co-propagating in underdense plasma
Mahdy, A.I.
2004-09-01
2D simulations code was constructed in order simulate the interactions of two co-propagating laser beams with underdense plasma. Simulations results at different laser intensities and separation-distances between the beams centroids were presented. In the results the effects of the laser intensities on the self-focusing and merging of the propagating beams were shown. In addition, the influence of increasing the separation-distance on the beams stability and trajectories were studied. A comparison with previous simulations at similar conditions was carried out in order to evaluate the numerical technique used to solve the basic equations. (author)
Vitte, P.A.; Harthe, C.; Lestage, P.; Claustrat, B.; Bobillier, P.
1988-01-01
The distribution of 14C-Melatonin (14C-MT) after systemic injection was studied in the plasma, cerebrospinal fluid (CSF), and brain of rats. Chromatographic analysis (thin-layer chromatography and high-performance liquid chromatography) indicated that the radioactivity from biological samples taken at various times following the injection of label was mainly associated with 14C-MT. Computer analysis of plasma 14C-MT kinetics showed a three-compartment system with half-lives of 0.21 +/- 0.05, 5.97 +/- 1.11, and 47.52 +/- 8.86 min. The volume of distribution and the clearance were 1,736 +/- 349 ml.kg-1 and 25.1 +/- 1.7 ml.min-1.kg-1 respectively. The entry of 14C-MT into the CSF was rapid and reached a maximum at 5 min. The decay followed a two-compartment system with half-lives of 16.5 +/- 2.9 and 47.3 +/- 8.6 min. The CSF/plasma concentration ratio was 0.38 at the steady state (30 min). At 2 min the level of 14C-MT in the brain was 3.8 higher than in the CSF. Representative autoradiograms revealed an heterogeneous localization of 14C-MT in the grey matter. The highest regional values, as evaluated by the permeability area product technique, were found in cortex, thalamic nuclei, medial geniculate nucleus, anterior pretectal area, paraventricular nucleus of the hypothalamus, choroid plexuses, and bulb-pons. Thirty minutes later 14C-MT was still detected in most of the brain regions analyzed. These results point to a low but rapid penetration of circulating MT into the brain and the CSF. The heterogeneous distribution and the partial retention of 14C-MT in the brain are compatible with the hypothesis of a central action of this hormone mediated via binding sites
Sazhin, S.S.
1995-01-01
Traditional applications of the commercial CFD package FLUENT include modelling of gas and liquid flows, combustion processes, thermal radiation exchange, particle dynamics and related processes of industrial interest. Recently, however, the area of applications of this package has been extended to modelling of new processes such as CO 2 laser discharges and the solution of the Boltzmann equation. Results of this modelling were reported at XXI International Conference on Phenomena in Ionized gases in Bochum and were later published in a number of research papers. The aim of this report is to summarize some further latest developments of the FLUENT package aimed to adjust it to the needs of modelling of plasma processes including those in ionized gases. The simplest way to modify this package is to include Amper force into Navier-Stokes equation and Ohm heating term into the enthalpy equation. In most cases, however, electric currents and electric and magnetic fields used in these equations cannot be assumed to be a priori known as they depend on plasma dynamics (distribution of velocities and pressures) and thermodynamics (distribution of temperatures) which implicitly enter into Maxwell or any equivalent electromagnetic equations. This makes it necessary to include these electromagnetic equations into the general iteration loop used in FLUENT
Cui, Dong; Han, GuangWei; Shang, YongGang; Mu, LiJun; Long, QingZhi; Du, YueFeng
2015-01-01
Prostatitis is a common disease in urology departments. Prostatic zinc accumulation is connected with the secretory function of the prostate, and zinc concentrations present in prostatic diseases differ greatly from the normal level. Studies have investigated the effect of chronic prostatitis on zinc concentration of prostatic fluid and seminal plasma, but have shown inconsistent results. Hence, we performed a systematic literature review and meta-analysis to assess the effect of chronic prostatitis on the zinc concentration of prostatic fluid and seminal plasma. Systematic literature searches were conducted with PubMed, Embase, Science Direct/Elsevier, CNKI and the Cochrane Library up to March 2015 for case-control studies that involved the relationship between chronic prostatitis and zinc concentration of prostatic fluid and seminal plasma. Meta-analysis was performed with Review Manager and Stata software. Standard mean differences (SMDs) of zinc concentration were identified with 95% confidence intervals (95% CIs) in a random- or fixed-effects model. Our results illustrated that the zinc concentrations in prostatic fluid and seminal plasma from chronic prostatitis patients were significantly lower than normal controls (SMD [95% CI] -246.71 [-347.97, -145.44], -20.74 [-35.11, -6.37], respectively). The sample size of each study was relatively small, and a total of 731 chronic prostatitis patients and 574 normal controls were investigated in all fourteen studies. Several studies related to the subject were excluded due to lack of control data or means and standard deviations. The present study illustrates that there was a significant negative effect of chronic prostatitis on zinc concentrations of prostatic fluid and seminal plasma. Further studies with larger sample sizes are needed to better illuminate the negative impact of chronic prostatitis on zinc concentrations.
Hua, Weizhuo; Fukagata, Koji
2018-04-01
Two-dimensional numerical simulation of a surface dielectric barrier discharge (SDBD) plasma actuator, driven by a nanosecond voltage pulse, is conducted. A special focus is laid upon the influence of grid resolution on the computational result. It is found that the computational result is not very sensitive to the streamwise grid spacing, whereas the wall-normal grid spacing has a critical influence. In particular, the computed propagation velocity changes discontinuously around the wall-normal grid spacing about 2 μm due to a qualitative change of discharge structure. The present result suggests that a computational grid finer than that was used in most of previous studies is required to correctly capture the structure and dynamics of streamer: when a positive nanosecond voltage pulse is applied to the upper electrode, a streamer forms in the vicinity of upper electrode and propagates along the dielectric surface with a maximum propagation velocity of 2 × 108 cm/s, and a gap with low electron and ion density (i.e., plasma sheath) exists between the streamer and dielectric surface. Difference between the results obtained using the finer and the coarser grid is discussed in detail in terms of the electron transport at a position near the surface. When the finer grid is used, the low electron density near the surface is caused by the absence of ionization avalanche: in that region, the electrons generated by ionization is compensated by drift-diffusion flux. In contrast, when the coarser grid is used, underestimated drift-diffusion flux cannot compensate the electrons generated by ionization, and it leads to an incorrect increase of electron density.
Azadeh Hashemian
2008-06-01
Full Text Available Enhanced surface heat exchangers are commonly used all worldwide. If applicable, due to their complicated geometry, simulating corrugated plate heat exchangers is a time-consuming process. In the present study, first we simulate the heat transfer in a sharp V-shape corrugation cell with constant temperature walls; then, we use a Locally Linear Neuro-Fuzzy method based on a radial basis function (RBFs to model the temperature field in the whole channel. New approach is developed to deal with fast computational and low memory resources that can be used with the largest available data sets. The purpose of the research is to reveal the advantages of proposed Neuro-Fuzzy model as a powerful modeling system designed for predicting and to make a fair comparison between it and the successful FLUENT simulated approaches in its best structures.
Canisso, Igor F; Ball, Barry A; Scoggin, Kirsten E; Squires, Edward L; Williams, Neil M; Troedsson, Mats H
2015-03-01
The objectives of this study were to: (i) determine alpha-fetoprotein (AFP) concentrations in fetal fluids (FF), and (ii) compare plasma concentrations of AFP in mares with placentitis (n=17) and gestationally age-matched control mares (n=17). Fetal fluid sampling (FFS, n=7/group) was performed at 0, 5 and 12 days post inoculation (DPI) or until abortion. Plasma was harvested daily for 12 days or until abortion. Placentitis was induced via intracervical inoculation of Streptococcus equi ssp. zooepidemicus. Proteins present in the FF were resolved by 1D-SDS-PAGE, and immunoblotting was used to detect the presence of AFP in fetal fluids. Concentrations of AFP in FF and plasma were determined with a chemiluminescence immunoassay. Mixed models for DPI, and for days from abortion (DFA) were used to analyze plasma concentrations of AFP. A protein band ∼68kDa consistent with the AFP size was present in all samples of fetal fluids examined. Immunoblotting for AFP revealed a single protein band (∼68kDa) in all samples. Concentrations of AFP in FF appeared higher than those in maternal plasma. There were effects of time (DPI p<0.0001; DFA p=0.0002) and time-by-group interactions (DPI*Group p<0.06; Group*DFA p<0.001). This study confirmed that AFP is present in the FF of mares during the third trimester of pregnancy. Experimentally induced placentitis was associated with an elevation in maternal plasma concentrations of AFP. Copyright © 2015 Elsevier B.V. All rights reserved.
Liang, Ying-Shuang; Liu, Gang-Hu; Xue, Chan; Liu, Yong-Xin; Wang, You-Nian
2017-05-01
A two-dimensional self-consistent fluid model and the experimental diagnostic are employed to investigate the dependencies of species concentrations on the gas proportion in the capacitive N2/Ar discharges operated at 60 MHz, 50 Pa, and 140 W. The results indicate that the N2/Ar proportion has a considerable impact on the species densities. As the N2 fraction increases, the electron density, as well as the Ar+ and Arm densities, decreases remarkably. On the contrary, the N2 + density is demonstrated to increase monotonically with the N2 fraction. Moreover, the N density is observed to increase significantly with the N2 fraction at the N2 fractions below 40%, beyond which it decreases slightly. The electrons are primarily generated via the electron impact ionization of the feed gases. The electron impact ionization of Ar essentially determines the Ar+ density. For the N2 + production, the charge transition process between the Ar+ ions and the feed gas N2 dominates at low N2 fraction, while the electron impact ionization of N2 plays the more important role at high N2 fraction. At any gas mixtures, more than 60% Arm atoms are generated through the radiative decay process from Ar(4p). The dissociation of the feed gas N2 by the excited Ar atoms and by the electrons is responsible for the N formation at low N2 fraction and high N2 fraction, respectively. To validate the simulation results, the floating double probe and the optical emission spectroscopy are employed to measure the total positive ion density and the emission intensity originating from Ar(4p) transitions, respectively. The results from the simulation show a qualitative agreement with that from the experiment, which indicates the reliable model.
Chang-Jian, C.-W.; Chen, C.-K.
2008-01-01
This study presents a dynamic analysis of a flexible rotor supported by two porous squeeze couple stress fluid film journal bearings with non-linear suspension. The dynamics of the rotor center and bearing center are studied. The analysis of the rotor-bearing system is investigated under the assumptions of non-Newtonian fluid and a short bearing approximation. The spatial displacements in the horizontal and vertical directions are considered for various non-dimensional speed ratios. The dynamic equations are solved using the Runge-Kutta method. The analysis methods employed in this study is inclusive of the dynamic trajectories of the rotor center and bearing center, power spectra, Poincare maps and bifurcation diagrams. The maximum Lyapunov exponent analysis is also used to identify the onset of chaotic motion. The numerical results show that the stability of the system varies with the non-dimensional speed ratios, the non-dimensional parameter l* and the permeability. The modeling results thus obtained by using the method proposed in this paper can be employed to predict the stability of the rotor-bearing system and the undesirable behavior of the rotor and bearing center can be avoided
Morrin, Shane; Lettieri, Paola; Chapman, Chris; Mazzei, Luca
2012-01-01
Highlights: ► We investigate sulphur during MSW gasification within a fluid bed-plasma process. ► We review the literature on the feed, sulphur and process principles therein. ► The need for research in this area was identified. ► We perform thermodynamic modelling of the fluid bed stage. ► Initial findings indicate the prominence of solid phase sulphur. - Abstract: Gasification of solid waste for energy has significant potential given an abundant feed supply and strong policy drivers. Nonetheless, significant ambiguities in the knowledge base are apparent. Consequently this study investigates sulphur mechanisms within a novel two stage fluid bed-plasma gasification process. This paper includes a detailed review of gasification and plasma fundamentals in relation to the specific process, along with insight on MSW based feedstock properties and sulphur pollutant therein. As a first step to understanding sulphur partitioning and speciation within the process, thermodynamic modelling of the fluid bed stage has been performed. Preliminary findings, supported by plant experience, indicate the prominence of solid phase sulphur species (as opposed to H 2 S) – Na and K based species in particular. Work is underway to further investigate and validate this.
Thomas, E.
2004-01-01
The rotation of a plasma is one of the most fundamental global modes of plasma behavior. It is the zeroth order plasma response to a transverse electric field. In its simplest kinetic form, the so-called E x B drift (here, E is the electric field vector and B is the magnetic field vector), both the ions and the electrons will undergo a drift in the same direction. This motion is considered a universal mode of a plasma since the mechanism of the E x B drift is, to zero-order, independent of both the mass and the charge of the particles
Geng, Yajie; Zhao, Longshan; Zhao, Juanhang; Guo, Bei; Ma, Panqin; Li, Yuanyuan; Zhang, Tianhong
2014-01-15
A simple, novel, rapid and sensitive supercritical fluid chromatography-tandem mass spectrometry (SFC-MS/MS) method was developed and validated for the determination of lacidipine in beagle dog plasma with nimodipine as internal standard. The method involved a simple liquid-liquid extraction method with tert-butyl methyl ether. The analytes were analyzed on an Acquity UPC(2) with a HSS C18 SB column (3mm×100mm, 1.8μm) set at 50°C. The mobile phase was carbon dioxide (≥99.99%) and methanol (92:8, v/v) at a flow rate of 2ml/min, the compensation solvent was methanol with 2% formic acid at a flow rate of 0.2ml/min and a total analysis time of 1.5min for each sample. The multiple reaction-monitoring mode was used for quantification of ion transitions at m/z 473.32→354.10 and 419.00→343.10 for lacidipine and internal standard, respectively. The linearity range of proposed method was 0.10-100ng/ml) (r(2)≥0.9990). The intra- and inter-day precision values were less than 15% and accuracy was from -0.83% to 3.27% at all quality control levels. The proposed method was successfully applied to a pharmacokinetic study of lacidipine in beagle dogs. Copyright © 2013 Elsevier B.V. All rights reserved.
Su, Chong; Yang, Hong; Meng, Xiangjun; Fawcett, J Paul; Cao, Jianming; Yang, Yan; Gu, Jingkai
2017-02-01
Rabeprazole is a novel benzimidazole proton pump inhibitor used for the treatment of gastrointestinal disorders. It is a chiral molecule that gives rise to the possibility of stereoselective pharmacokinetics. To investigate this phenomenon, a rapid and sensitive chiral assay based on supercritical fluid chromatography tandem mass spectrometry was developed and applied to the determination of (R)-rabeprazole and (S)-rabeprazole in dog plasma. Sample preparation involved protein precipitation with acetonitrile after the addition of (R)-lansoprazole as internal standard. Baseline separation of enantiomers in 4.5 min was achieved on an Acquity UPC 2 system using an ACQUITY UPC 2 Trefoil CEL2 column maintained at 60°C and a mobile phase consisting of methanol/CO 2 (30:70, v/v) delivered at 2.5 mL/min. Detection was achieved by multiple reaction monitoring of the transitions at m/z 360.0→242.2 (rabeprazole) and 370.3→252.0 (internal standard) in the positive ion mode. The assay was linear in the range of 1-1000 ng/mL and free of matrix effects. Intra- and interday precisions were less than 10.0% with accuracy in the range of -2.6 to 3.1%. The method was successfully applied to a pharmacokinetic study of rabeprazole enantiomers after administration of a single oral dose of 10 mg racemate to beagle dogs. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Mamun, A. A.
2014-01-01
The propagation of finite amplitude ultra-low-frequency shear dust Alfvén (SDA) waves, and their modulational instability in a magnetized plasma medium of positive and negatively charged dust fluids have been theoretically investigated by using the reductive perturbation method. The derivative nonlinear Schrödinger equation is derived to examine the stability analysis of such SDA waves. It is found that the SDA waves propagating in such an opposite polarity dust plasma medium are modulationally unstable, and that the instability criterion and the growth rate of these unstable SDA waves in such a novel opposite polarity dust plasma medium are found to be significantly different from those in electron–ion or electron–positron plasma media. The implications of the present investigation in different space environments and laboratory devices are briefly discussed.
Bee K Tan
Full Text Available OBJECTIVES: Circulating Fibroblast Growth Factor 21 (FGF21 levels are increased in insulin resistant states such as obesity, type 2 diabetes mellitus and gestational diabetes mellitus (GDM. In addition, GDM is associated with serious maternal and fetal complications. We sought to study human cerebrospinal fluid (CSF and corresponding circulating FGF21 levels in women with gestational diabetes mellitus (GDM and in age and BMI matched control subjects. We also assessed FGF21 secretion from GDM and control human placental explants. DESIGN: CSF and corresponding plasma FGF21 levels of 24 women were measured by ELISA [12 GDM (age: 26-47 years, BMI: 24.3-36.3 kg/m(2 and 12 controls (age: 22-40 years, BMI: 30.1-37.0 kg/m(2]. FGF21 levels in conditioned media were secretion from GDM and control human placental explants were also measured by ELISA. RESULTS: Glucose, HOMA-IR and circulating NEFA levels were significantly higher in women with GDM compared to control subjects. Plasma FGF21 levels were significantly higher in women with GDM compared to control subjects [234.3 (150.2-352.7 vs. 115.5 (60.5-188.7 pg/ml; P<0.05]. However, there was no significant difference in CSF FGF21 levels in women with GDM compared to control subjects. Interestingly, CSF/Plasma FGF21 ratio was significantly lower in women with GDM compared to control subjects [0.4 (0.3-0.6 vs. 0.8 (0.5-1.6; P<0.05]. FGF21 secretion into conditioned media was significantly lower in human placental explants from women with GDM compared to control subjects (P<0.05. CONCLUSIONS: The central actions of FGF21 in GDM subjects maybe pivotal in the pathogenesis of insulin resistance in GDM subjects. The significance of FGF21 produced by the placenta remains uncharted and maybe crucial in our understanding of the patho-physiology of GDM and its associated maternal and fetal complications. Future research should seek to elucidate these points.
Murphy, V A; Rapoport, S I
1988-06-28
Recent studies have shown regulation of central nervous system [Ca] after chronic hypo- and hypercalcemia. To investigate the mechanism of this regulation, 3-week-old rats were fed diets for 8 weeks that contained low or normal levels of Ca. Plasma [Ca] was 40% less in rats fed the low Ca diet than in animals fed normal diet. Unidirectional transfer coefficients for Ca (KCa) and Cl (KCl) into cerebrospinal fluid (CSF) and brain were determined from the 10 min uptake of intravenously injected 45Ca and 36Cl in awake animals. KCa for CSF was 68% greater in low-Ca rats than in normal rats. Likewise, the values of KCa for brain regions with areas adjacent to the ventricles like the hippocampus and pons-medulla were 50% higher than in normal animals. On the other hand, KCas for parietal cortex, a brain region distant from the choroid plexus and not expected to be influenced by Ca entry into CSF, were similar between the groups. Comparison of the regional ratios of KCa/KCl revealed that a selective increase of Ca transport occurred into CSF and all brain regions except the parietal cortex in Ca-deficient rats. The results suggest that Ca homeostasis of CSF and brain [Ca] during chronic hypocalcemia is due to increased transfer of Ca from blood to brain, and that the regulation occurs via the CSF, possibly at the choroid plexus, but not via the cerebral capillaries.
Masti, Robert; Srinivasan, Bhuvana; King, Jacob; Stoltz, Peter; Hansen, David; Held, Eric
2017-10-01
Recent results from experiments and simulations of magnetically driven pulsed power liners have explored the role of early-time electrothermal instability in the evolution of the MRT (magneto-Rayleigh-Taylor) instability. Understanding the development of these instabilities can lead to potential stabilization mechanisms; thereby providing a significant role in the success of fusion concepts such as MagLIF (Magnetized Liner Inertial Fusion). For MagLIF the MRT instability is the most detrimental instability toward achieving fusion energy production. Experiments of high-energy density plasmas from wire-array implosions have shown the requirement for more advanced physics modeling than that of ideal magnetohydrodynamics. The overall focus of this project is on using a multi-fluid extended-MHD model with kinetic closures for thermal conductivity, resistivity, and viscosity. The extended-MHD model has been updated to include the SESAME equation-of-state tables and numerical benchmarks with this implementation will be presented. Simulations of MRT growth and evolution for MagLIF-relevant parameters will be presented using this extended-MHD model with the SESAME equation-of-state tables. This work is supported by the Department of Energy Office of Science under Grant Number DE-SC0016515.
Vesna Selakovic
2009-01-01
Full Text Available The aim of this study was to define concentration changes of soluble adhesion molecules (sICAM-1, sVCAM-1 and sE-Selectin in cerebrospinal fluid and plasma, as well as, number of peripheral blood leukocytes and the albumin coefficient in the patients with the acute brain infarction. We also, analyzed the correlation between the measured levels, the infarct volume and the degree of neurological and the functional deficit. The study included 50 patients with the acute cerebral infarction and the control group consisted of 16 patients, age and sex matched. Obtained results showed significant increase in number of leukocytes, the albumin coefficient and the level of soluble adhesion molecules within the first seven days in patients. The highest values of measured parameters were noted within the third and the fourth day after the insult, which is the suggested period of maximal intensity of inflammatory reactions. Significant correlation was found between measured parameters and the infarct volume, the degree of neurological and the functional deficit. The results suggest that investigated parameters in CSF and blood represent a dynamic index of inflammatory events as one of the fundametal mechanisms responsible for neuron damage during acute phase of brain infarction.
Otsuka, Yuichi; Kawaguchi, Hayato; Mutoh, Yoshiharu
2016-10-01
This study aimed to clarify the effect of a simulated body fluid (SBF) on the cyclic delamination behavior of a plasma-sprayed hydroxapatite (HAp) coating. A HAp coating is deposited on the surfaces of surgical metallic materials in order to enhance the bond between human bone and such surfaces. However, the HAp coating is susceptible to delamination by cyclic loading from the patient's gait. Although hip joints are subjected to both positive and negative moments, only the effects of tensile bending stresses on vertical crack propagation behavior have been investigated. Thus, the cyclic delamination behavior of a HAp coating was observed at the stress ratio R=-1 in order to determine the effects of tensile/compressive loading on the delamination behavior. The delamination growth rate increased with SBF immersion, which decreased the delamination life. Raman spectroscopy analysis revealed that the selective phase dissolution in the HAp coating was promoted at interfaces. Finite element analysis revealed that the energy release rate Gmax showed a positive value even in cases with compressive loading, which is a driving force for the delamination of a HAp coating. A prediction model for the delamination growth life was developed that combines a fracture mechanics parameter with the assumed stress-dependent dissolution rate. The predicted delamination life matched the experimental data well in cases of lower stress amplitudes with SBF. Copyright © 2016 Elsevier B.V. All rights reserved.
Blue, Brent Edward
2005-01-01
In the plasma-wakefield experiment at SLAC, known as E157, an ultra-relativistic electron beam is used to both excite and witness a plasma wave for advanced accelerator applications. If the beam is tilted, then it will undergo transverse oscillations inside of the plasma. These oscillations can grow exponentially via an instability know as the electron hose instability. The linear theory of electron-hose instability in a uniform ion column predicts that for the parameters of the E157 experiment (beam charge, bunch length, and plasma density) a growth of the centroid offset should occur. Analysis of the E157 data has provided four critical results. The first was that the incoming beam did have a tilt. The tilt was much smaller than the radius and was measured to be 5.3 (micro)m/(delta) z at the entrance of the plasma (IP1.) The second was the beam centroid oscillates in the ion channel at half the frequency of the beam radius (betatron beam oscillations), and these oscillations can be predicted by the envelope equation. Third, up to the maximum operating plasma density of E157 (∼2 x 10 14 cm -3 ), no growth of the centroid offset was measured. Finally, time-resolved data of the beam shows that up to this density, no significant growth of the tail of the beam (up to 8ps from the centroid) occurred even though the beam had an initial tilt
Blue, Brent Edward; /SLAC /UCLA
2005-10-10
In the plasma-wakefield experiment at SLAC, known as E157, an ultra-relativistic electron beam is used to both excite and witness a plasma wave for advanced accelerator applications. If the beam is tilted, then it will undergo transverse oscillations inside of the plasma. These oscillations can grow exponentially via an instability know as the electron hose instability. The linear theory of electron-hose instability in a uniform ion column predicts that for the parameters of the E157 experiment (beam charge, bunch length, and plasma density) a growth of the centroid offset should occur. Analysis of the E157 data has provided four critical results. The first was that the incoming beam did have a tilt. The tilt was much smaller than the radius and was measured to be 5.3 {micro}m/{delta}{sub z} at the entrance of the plasma (IP1.) The second was the beam centroid oscillates in the ion channel at half the frequency of the beam radius (betatron beam oscillations), and these oscillations can be predicted by the envelope equation. Third, up to the maximum operating plasma density of E157 ({approx}2 x 10{sup 14} cm{sup -3}), no growth of the centroid offset was measured. Finally, time-resolved data of the beam shows that up to this density, no significant growth of the tail of the beam (up to 8ps from the centroid) occurred even though the beam had an initial tilt.
Meany, Holly J; Fox, Elizabeth; McCully, Cynthia; Tucker, Chris; Balis, Frank M
2008-08-01
Erlotinib hydrochloride is a small molecule inhibitor of epidermal growth factor receptor (EGFR). EGFR is over-expressed in primary brain tumors and solid tumors that metastasize to the central nervous system. We evaluated the plasma and cerebrospinal fluid (CSF) pharmacokinetics of erlotinib and its active metabolite OSI-420 after an intravenous (IV) dose in a non-human primate model. Erlotinib was administered as a 1 h IV infusion to four adult rhesus monkeys. Serial blood and CSF samples were drawn over 48 h and erlotinib and OSI-420 were quantified with an HPLC/tandem mass spectroscopic assay. Pharmacokinetic parameters were estimated using non-compartmental and compartmental methods. CSF penetration was calculated from the AUC(CSF):AUC(plasma). Erlotinib disappearance from plasma after a short IV infusion was biexponential with a mean terminal half-life of 5.2 h and a mean clearance of 128 ml/min per m(2). OSI-420 exposure (AUC) in plasma was 30% (range 12-59%) of erlotinib, and OSI-420 clearance was more than 5-fold higher than erlotinib. Erlotinib and OSI-420 were detectable in CSF. The CSF penetration (AUC(CSF):AUC(plasma)) of erlotinib and OSI-420 was OSI-420 are measurable in CSF after an IV dose. The drug exposure (AUC) in the CSF is limited relative to total plasma concentrations but is substantial relative the free drug exposure in plasma.
Optics and Fluid Dynamics Department. Annual progress report for 2003
Bindslev, H.; Hanson, S.G.; Lynov, J.P.; Petersen, P.M.; Skaarup, B.
2004-05-01
The Optics and Fluid Dynamics Department performs basic and applied research within three scientific programmes: (1 laser systems and optical materials, (2 optical diagnostics and information processing and (3 plasma and fluid dynamics. The department has core competences in: optical sensors, optical materials, optical storage, biophotonics, numerical modelling and information processing, non-linear dynamics, fusion plasma physics and plasma technology. The research is supported by several EU programmes, including EURATOM, by Danish research councils and by industry. A summary of the activities in 2003 is presented. (au)
Colunga S, S.
1990-07-01
In this report the simplified analysis of a method to detect the movement of the plasma column of a tokamak in the vertical direction and of the biggest radius is given. The peculiar case of the Tokamak Novillo of the Plasma Physics Laboratory of the ININ is studied. (Author)
Berggrund, Malin; Ekman, Daniel; Gustavsson, Inger; Sundfeldt, Karin; Olovsson, Matts; Enroth, Stefan; Gyllensten, Ulf
2016-01-01
The indicating FTA elute micro cardTM has been developed to collect and stabilize the nucleic acid in biological samples and is widely used in human and veterinary medicine and other disciplines. This card is not recommended for protein analyses, since surface treatment may denature proteins. We studied the ability to analyse proteins in human plasma and vaginal fluid as applied to the indicating FTA elute micro cardTM using the sensitive proximity extension assay (PEA). Among 92 proteins in ...
Lue Xing; Zhu Hongwu; Yao Zhenzhi; Meng Xianghua; Zhang Cheng; Zhang Chunyi; Tian Bo
2008-01-01
In this paper, the multisoliton solutions in terms of double Wronskian determinant are presented for a generalized variable-coefficient nonlinear Schroedinger equation, which appears in space and laboratory plasmas, arterial mechanics, fluid dynamics, optical communications and so on. By means of the particularly nice properties of Wronskian determinant, the solutions are testified through direct substitution into the bilinear equations. Furthermore, it can be proved that the bilinear Baecklund transformation transforms between (N - 1)- and N-soliton solutions
Naidoo, Kristina; Chuturgoon, Anil; Cliff, Geremy; Singh, Sanil; Ellis, Megan; Otway, Nicholas; Vosloo, Andre; Gregory, Michael
2017-07-01
We studied the possible metal offloading onto the progeny of three pregnant female ragged-tooth sharks (Carcharias taurus) (C. taurus). The presences of five metals, i.e. aluminium (Al), arsenic (As), cadmium (Cd), lead (Pb) and selenium (Se) were validated by mass spectrometry in the maternal plasma as well as the intracapsular and uterine fluids (UF) in which embryos develop. Metals were ranked in a decreasing concentration as follows: Plasma: As > Al > Se > Pb > Cd; ICF: As > Se > Al > Cd > Pb and UF: As > Se > Al > Cd > Pb. As was present in the highest concentration in all three sharks. Al, Pb and Cd were found to be the highest within the plasma, while concentrations of Se were similar in all three fluids. These results indicate that C. taurus embryos are exposed to metals during early development, but the impact of this exposure remains unknown. To the best of our knowledge, this is the first investigation to confirm the presence of metals in the fluids that surround the developing C. taurus embryos, a species that is already listed as vulnerable.
... Plasma Free Metanephrines Platelet Count Platelet Function Tests Pleural Fluid Analysis PML-RARA Porphyrin Tests Potassium Prealbumin ... is being tested? Synovial fluid is a thick liquid that acts as a lubricant for the body's ...
Mohamed, B.F.; El-Shorbagy, Kh.H.
2000-01-01
A general detailed analysis for the nonlinear generation of localized fields due to the existence of a strong pump field inside the non-uniform plasma has been considered. We have taken into account the effects of relativistic and non-local nonlinearities on the structure of plasma resonance region. The nonlinear Schrodinger equation described the localized fields are investigated. Besides, the generalized dispersion relation is obtained to study the modulational instabilities in different cases. Keywords: Wave-plasma interaction, Nonlinear effects, Modulation instabilities
Gruber, Jan
2011-01-01
Roč. 56, č. 2 (2011), s. 185-205 ISSN 0001-7043 Institutional research plan: CEZ:AV0Z20570509 Keywords : correlation dimension * time-embeddings * chaos Subject RIV: BL - Plasma and Gas Discharge Physics
Spatial and Time Dynamics of Non-Linear Vortices in Plasma Lens for High-Current Ion Beam Focusing
Goncharov, Alexei A.; Maslov, Vasyl I.; Onishchenko, Ivan N.; Tretyakov, Vitalij N.
2002-11-01
It is known from numerical simulation (see, for example, [1]) and from experiments (see, for example, [2]), that an electron density bunches as discrete vortices are long - living structures in vacuum. However, in laboratory experiments [2] it has been shown that the vortices are changed faster, when they are submersed in electrons, distributed around them. The charged plasma lens intended for a focussing of high-current ion beams, has the same crossed configuration of a radial electrical and longitudinal magnetic field [3], as only electron plasma. In this lens the vortical turbulence is excited [3]. The vortex - bunch and vortex - hole are rotated in the inverse directions in system of their rest. The instability development in initially homogeneous plasma causes that the vortices are excited by pairs. Namely, if the vortex - bunch of electrons is generated, near the vortex - hole of electrons is also generated. It is shown, that in nonuniform plasma the vortices behave is various in time. Namely, the vortex - bunch goes to area of larger electron density, and the vortex - hole goes to area of smaller electron density. The speed of the vortex - hole is less than speed of the vortex - bunch. It is shown, that the electron vortices, generated in the plasma lens, can result in to formation of spiral distribution of electron density. The physical mechanism of coalescence of electron vortices - bunches is proposed. 1.Driscoll C.F. et al. Plasma Phys. Contr. Fus. Res. 3 (1989) 507. 2.Kiwamoto Y. et al. Non-neutral plasma physics. Princeton. 1999. P. 99-105. 3.Goncharov A. et al. Plasma Phys. Rep. 20 (1994) 499.
Morgan, T. W.; Rindt, P.; van Eden, G. G.; Kvon, V.; Jaworksi, M. A.; Lopes Cardozo, N. J.
2018-01-01
For DEMO and beyond, liquid metal plasma-facing components are considered due to their resilience to erosion through flowed replacement, potential for cooling beyond conduction and inherent immunity to many of the issues of neutron loading compared to solid materials. The development curve of liquid metals is behind that of e.g. tungsten however, and tokamak-based research is currently somewhat limited in scope. Therefore, investigation into linear plasma devices can provide faster progress under controlled and well-diagnosed conditions in assessing many of the issues surrounding the use of liquid metals. The linear plasma devices Magnum-PSI and Pilot-PSI are capable of producing DEMO-relevant plasma fluxes, which well replicate expected divertor conditions, and the exploration of physics issues for tin (Sn) and lithium (Li) such as vapour shielding, erosion under high particle flux loading and overall power handling are reviewed here. A deeper understanding of erosion and deposition through this work indicates that stannane formation may play an important role in enhancing Sn erosion, while on the other hand the strong hydrogen isotope affinity reduces the evaporation rate and sputtering yields for Li. In combination with the strong redeposition rates, which have been observed under this type of high-density plasma, this implies that an increase in the operational temperature range, implying a power handling range of 20-25 MW m-2 for Sn and up to 12.5 MW m-2 for Li could be achieved. Vapour shielding may be expected to act as a self-protection mechanism in reducing the heat load to the substrate for off-normal events in the case of Sn, but may potentially be a continual mode of operation for Li.
Ogilvie, Gordon I.
2016-06-01
> These lecture notes and example problems are based on a course given at the University of Cambridge in Part III of the Mathematical Tripos. Fluid dynamics is involved in a very wide range of astrophysical phenomena, such as the formation and internal dynamics of stars and giant planets, the workings of jets and accretion discs around stars and black holes and the dynamics of the expanding Universe. Effects that can be important in astrophysical fluids include compressibility, self-gravitation and the dynamical influence of the magnetic field that is `frozen in' to a highly conducting plasma. The basic models introduced and applied in this course are Newtonian gas dynamics and magnetohydrodynamics (MHD) for an ideal compressible fluid. The mathematical structure of the governing equations and the associated conservation laws are explored in some detail because of their importance for both analytical and numerical methods of solution, as well as for physical interpretation. Linear and nonlinear waves, including shocks and other discontinuities, are discussed. The spherical blast wave resulting from a supernova, and involving a strong shock, is a classic problem that can be solved analytically. Steady solutions with spherical or axial symmetry reveal the physics of winds and jets from stars and discs. The linearized equations determine the oscillation modes of astrophysical bodies, as well as their stability and their response to tidal forcing.
Laeger, T; Wirthgen, E; Piechotta, M; Metzger, F; Metges, C C; Kuhla, B; Hoeflich, A
2014-05-01
Hormones and metabolites act as satiety signals in the brain and play an important role in the control of feed intake (FI). These signals can reach the hypothalamus and brainstem, 2 major centers of FI regulation, via the blood stream or the cerebrospinal fluid (CSF). During the early lactation period of high-yielding dairy cows, the increase of FI is often insufficient. Recently, it has been demonstrated that insulin-like growth factors (IGF) may control FI. Thus, we asked in the present study if IGF-binding proteins (IGFBP) are regulated during the periparturient period and in response to feed restriction and therefore might affect FI as well. In addition, we specifically addressed conditional distribution of IGFBP in plasma and CSF. In one experiment, 10 multiparous German Holstein dairy cows were fed ad libitum and samples of CSF and plasma were obtained before morning feeding on d -20, -10, +1, +10, +20, and +40 relative to calving. In a second experiment, 7 cows in second mid-lactation were sampled for CSF and plasma after ad libitum feeding and again after feeding 50% of the previous ad libitum intake for 4 d. Intact IGFBP-2, IGFBP-3, and IGFBP-4 were detected in plasma by quantitative Western ligand blot analysis. In CSF, we were able to predominantly identify intact IGFBP-2 and a specific IGFBP-2 fragment containing detectable binding affinities for biotinylated IGF-II. Whereas plasma concentrations of IGFBP-2 and IGFBP-4 increased during the periparturient period, IGFBP-3 was unaffected over time. In CSF, concentrations of IGFBP-2, both intact and fragmented, were not affected during the periparturient period. Plasma IGF-I continuously decreased until calving but remained at a lower concentration in early lactation than in late pregnancy. Food restriction did not affect concentrations of IGF components present in plasma or CSF. We could show that the IGFBP profiles in plasma and CSF are clearly distinct and that changes in IGFBP in plasma do not simply
Young-Hyo Ryu
Full Text Available Non-thermal plasma at atmospheric pressure has been actively applied to sterilization. However, its efficiency for inactivating microorganisms often varies depending on microbial species and environments surrounding the microorganisms. We investigated the influence of environmental factors (surrounding media on the efficiency of microbial inactivation by plasma using an eukaryotic model microbe, Saccharomyces cerevisiae, to elucidate the mechanisms for differential efficiency of sterilization by plasma. Yeast cells treated with plasma in water showed the most severe damage in viability and cell morphology as well as damage to membrane lipids, and genomic DNA. Cells in saline were less damaged compared to those in water, and those in YPD (Yeast extract, Peptone, Dextrose were least impaired. HOG1 mitogen activated protein kinase was activated in cells exposed to plasma in water and saline. Inactivation of yeast cells in water and saline was due to the acidification of the solutions by plasma, but higher survival of yeast cells treated in saline may have resulted from the additional effect related to salt strength. Levels of hydroxyl radical (OH· produced by plasma were the highest in water and the lowest in YPD. This may have resulted in differential inactivation of yeast cells in water, saline, and YPD by plasma. Taken together, our data suggest that the surrounding media (environment can crucially affect the outcomes of yeast cell plasma treatment because plasma modulates vital properties of media, and the toxic nature of plasma can also be altered by the surrounding media.
Ezato, Koichiro; Shimizu, Akihiko; Kunugi, Tomoaki.
1995-01-01
Numerical simulations are presented on the flow and heat transfer characteristics of an impinging round jet of argon plasma with atmospheric pressure. The target slab with finite thickness upon which plasma jet impinges is assumed to be as SiC which is a candidate material for plasma facing material of fusion reactor. The plasma jet is treated by use of a magnetohydrodynamics model that takes its two-temperature non-equilibrium state into account. The rear side of the target slab is assumed to be cooled by a gas-solid suspension impinging round jet. The result shows that the plasma is in non-equilibrium state in which the electron temperature is higher than the heavy particle in the outer region of plasma jet core and that the heat flux to the target slab is over 8 MW/m 2 in the region of the plasma jet core contacts. (author)
Wang, Yang; Fan, Rong; Luo, Jiekun; Tang, Tao; Xing, Zhihua; Xia, Zian; Peng, Weijun; Wang, Wenzhu; Lv, Huiying; Huang, Wei; Liang, Yizeng; Yi, Lunzhao; Lu, Hongmei; Huang, Xi
2015-04-01
Damage of blood-brain barrier is a common result of traumatic brain injury. This damage can open the blood-brain barrier and allow drug passage. An ultraperformance liquid chromatography with tandem mass spectrometry method was established to determine the concentration of rhein in the biofluids (plasma and cerebrospinal fluid) of patients with a compromised blood-brain barrier following traumatic brain injury after rhubarb administration. Furthermore, the pharmacokinetic profiles were analyzed. A triple-quadruple tandem mass spectrometer with electrospray ionization was used for rhein detection. The mass transition followed was m/z 283.06→239.0. The calibration curve was linear in the concentration range of 10-8000 ng/mL for the biofluids. The intra- and interday precisions were less than 10%. The relative standard deviation of recovery was less than 15% in biological matrices. The pharmacokinetic data showed that rhein was rapidly transported into biofluids, and exhibited a peak concentration 1 h after rhubarb administration. The elimination rate of rhein was slow. The AUCcerebrospinal fluid /AUCplasma (AUC is area under curve) of rhein was approximately 17%, indicating that portions of rhein could pass the impaired blood-brain barrier. The method was successfully applied to quantify rhein in the biofluids of all patients. The data presented can help to guide clinical applications of rhubarb for treating traumatic brain injury. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Guglieri-López, Beatriz; Pérez-Pitarch, Alejandro; Martinez-Gómez, Maria Amparo; Porta-Oltra, Begoña; Climente-Martí, Mónica; Merino-Sanjuán, Matilde
2016-12-01
A wide linearity range analytical method for the determination of lenalidomide in patients with multiple myeloma for pharmacokinetic studies is required. Plasma samples were ultrasonicated for protein precipitation. A solid-phase extraction was performed. The eluted samples were evaporated to dryness under vacuum, and the solid obtained was diluted and injected into the high-performance liquid chromatography (HPLC) system. Separation of lenalidomide was performed on an Xterra RP C18 (250 mm length × 4.6 mm i.d., 5 µm) using a mobile phase consisting of phosphate buffer/acetonitrile (85:15, v/v, pH 3.2) at a flow rate of 0.5 mL · min -1 The samples were monitored at a wavelength of 311 nm. A linear relationship with good correlation coefficient (r = 0.997, n = 9) was found between the peak area and lenalidomide concentrations in the range of 100 to 950 ng · mL -1 The limits of detection and quantitation were 28 and 100 ng · mL -1 , respectively. The intra- and interassay precisions were satisfactory, and the accuracy of the method was proved. In conclusion, the proposed method is suitable for the accurate quantification of lenalidomide in human plasma with a wide linear range, from 100 to 950 ng · mL -1 This is a valuable method for pharmacokinetic studies of lenalidomide in human subjects. © 2016 Society for Laboratory Automation and Screening.
Xiao, C. Z.; Zhuo, H. B.; Yin, Y.; Liu, Z. J.; Zheng, C. Y.; Zhao, Y.; He, X. T.
2018-02-01
Stimulated Raman sidescattering (SRSS) in inhomogeneous plasma is comprehensively revisited on both theoretical and numerical aspects due to the increasing concern of its detriments to inertial confinement fusion. Firstly, two linear mechanisms of finite beam width and collisional effects that could suppress SRSS are investigated theoretically. Thresholds for the eigenmode and wave packet in a finite-width beam are derived as a supplement to the theory proposed by Mostrom and Kaufman (1979 Phys. Rev. Lett. 42 644). Collisional absorption of SRSS is efficient at high-density plasma and high-Z material, otherwise, it allows emission of sidescattering. Secondly, we have performed the first three-dimensional particle-in-cell simulations in the context of SRSS to investigate its linear and nonlinear effects. Simulation results are qualitatively agreed with the linear theory. SRSS with the maximum growth gain is excited at various densities, grows to an amplitude that is comparable with the pump laser, and evolutes to lower densities with a large angle of emergence. Competitions between SRSS and other parametric instabilities such as stimulated Raman backscattering, two-plasmon decay, and stimulated Brillouin scattering are discussed. These interaction processes are determined by gains, occurrence sites, scattering geometries of each instability, and will affect subsequent evolutions. Nonlinear effects of self-focusing and azimuthal magnetic field generation are observed to be accompanied with SRSS. In addition, it is found that SRSS is insensitive to ion motion, collision (low-Z material), and electron temperature.
Plasma physics and instabilities
Lashmore-Davies, C.N.
1981-01-01
These lectures procide an introduction to the theory of plasmas and their instabilities. Starting from the Bogoliubov, Born, Green, Kirkwood, and Yvon (BBGKY) hierarchy of kinetic equations, the additional concept of self-consistent fields leads to the fundamental Vlasov equation and hence to the warm two-fluid model and the one-fluid MHD, or cold, model. The properties of small-amplitude waves in magnetized (and unmagnetized) plasmas, and the instabilities to which they give rise, are described in some detail, and a complete chapter is devoted to Landau damping. The linear theory of plasma instabilities is illustrated by the current-driven electrostatic kind, with descriptions of the Penrose criterion and the energy principle of ideal MHD. There is a brief account of the application of feedback control. The non-linear theory is represented by three examples: quasi-linear velocity-space instabilities, three-wave instabilities, and the stability of an arbitrarily largeamplitude wave in a plasma. (orig.)
Environmental enteropathy is subclinical inflammation of the upper gastrointestinal tract associated with reduced linear growth in developing countries. Usually investigators have used biopsy or a dual sugar absorption test to assess environmental enteropathy. Such tests are time and resource intens...
Popowicz, Natalia D; O'Halloran, Sean J; Fitzgerald, Deirdre; Lee, Y C Gary; Joyce, David A
2018-04-01
Piperacillin, in combination with tazobactam is a common first-line antibiotic used for the treatment of pleural infection, however its pleural pharmacokinetics and penetration has not previously been reported. The objective of this work was to develop and validate a rapid and sensitive liquid chromatography with tandem mass spectrometry (LC-MS/MS) assay for quantification of piperacillin (PIP) and tazobactam (TAZ). PIP and TAZ were extracted from both human plasma and pleural fluid samples by protein precipitation in methanol containing the internal standards (IS) piperacillin-d 5 (PIP-d 5 ) and sulbactam (SUL). Briefly, 5 μL of sample was mixed with 125 μL of methanol containing IS, vortexed and centrifuged. Supernatant (50 μL) was diluted into 500 μL of mobile phase containing 10 mM of ammonium bicarbonate in LCMS grade water and transferred to the autosampler tray. Electrospray ionization in positive mode and multiple reaction monitoring (MRM) were used for PIP and PIP-d 5 at the transitions m/z 518.2 → 143.2 and m/z 523.2 → 148.2 respectively, and electrospray ionization in negative mode and MRM were used for TAZ and SUL at the transitions m/z 299.1 → 138.1 and m/z 232.4 → 140.1. The chromatographic separation was achieved using an Acquity BEH C-18 column with gradient elution of mobile phase containing 10 mmol/L ammonium bicarbonate in water and methanol. A linear range was observed over the concentration range of 0.25-352 mg/L and 0.25-50.5 mg/L for PIP and TAZ respectively. Complete method validation was performed according to US FDA guidelines for selectivity, specificity, precision and accuracy, LLOQ, matrix effects, recovery and stability, with all results within acceptable limits. This method was successfully applied to two patients with pleural infection and is suitable for further pharmacokinetic studies and therapeutic drug monitoring. Crown Copyright © 2018. Published by Elsevier B.V. All rights reserved.
Aleksandrov, V. V.; Mitrofanov, K. N.; Gritsuk, A. N.; Frolov, I. N.; Grabovski, E. V.; Laukhin, Ya. N.
2013-01-01
Results are presented from experimental studies on the implosion of arrays made of wires and metalized fibers under the action of current pulses with an amplitude of up to 3.5 MA at the Angara-5-1 facility. The effect of the parameters of an additional linear mass of bismuth and gold deposited on the wires/fibers is investigated. It is examined how the material of the wires/fibers and the metal coating deposited on them affect the penetration of the plasma with the frozen-in magnetic field into a cylindrical array. Information on the plasma production rate for different metals is obtained by analyzing optical streak images of imploding arrays. The plasma production rate m-dot m for cylindrical arrays made of the kapron fibers coated with bismuth is determined. For the initial array radius of R 0 = 1 cm and discharge current of I = 1 MA, the plasma production rate is found to be m-dot m approx. 0.095 ± 0.015 μg/(cm 2 ns)
Berggrund, Malin; Ekman, Daniel; Gustavsson, Inger; Sundfeldt, Karin; Olovsson, Matts; Enroth, Stefan; Gyllensten, Ulf
2016-01-01
The indicating FTA elute micro card™ has been developed to collect and stabilize the nucleic acid in biological samples and is widely used in human and veterinary medicine and other disciplines. This card is not recommended for protein analyses, since surface treatment may denature proteins. We studied the ability to analyse proteins in human plasma and vaginal fluid as applied to the indicating FTA elute micro card™ using the sensitive proximity extension assay (PEA). Among 92 proteins in the Proseek Multiplex Oncology Iv2 panel, 87 were above the limit of detection (LOD) in liquid plasma and 56 among 92 above LOD in plasma applied to FTA cards. Washing and protein elution protocols were compared to identify an optimal method. Liquid-based cytology samples showed a lower number of proteins above LOD than FTA cards with vaginal fluid samples applied. Our results demonstrate that samples applied to the indicating FTA elute micro card™ are amendable to protein analyses, given that a sensitive protein detection assay is used. The results imply that biological samples applied to FTA cards can be used for DNA, RNA and protein detection. PMID:28936257
Malin Berggrund
2016-01-01
Full Text Available The indicating FTA elute micro card™ has been developed to collect and stabilize the nucleic acid in biological samples and is widely used in human and veterinary medicine and other disciplines. This card is not recommended for protein analyses, since surface treatment may denature proteins. We studied the ability to analyse proteins in human plasma and vaginal fluid as applied to the indicating FTA elute micro card™ using the sensitive proximity extension assay (PEA. Among 92 proteins in the Proseek Multiplex Oncology Iv2 panel, 87 were above the limit of detection (LOD in liquid plasma and 56 among 92 above LOD in plasma applied to FTA cards. Washing and protein elution protocols were compared to identify an optimal method. Liquid-based cytology samples showed a lower number of proteins above LOD than FTA cards with vaginal fluid samples applied. Our results demonstrate that samples applied to the indicating FTA elute micro card™ are amendable to protein analyses, given that a sensitive protein detection assay is used. The results imply that biological samples applied to FTA cards can be used for DNA, RNA and protein detection.
Berggrund, Malin; Ekman, Daniel; Gustavsson, Inger; Sundfeldt, Karin; Olovsson, Matts; Enroth, Stefan; Gyllensten, Ulf
2016-01-01
The indicating FTA elute micro card™ has been developed to collect and stabilize the nucleic acid in biological samples and is widely used in human and veterinary medicine and other disciplines. This card is not recommended for protein analyses, since surface treatment may denature proteins. We studied the ability to analyse proteins in human plasma and vaginal fluid as applied to the indicating FTA elute micro card™ using the sensitive proximity extension assay (PEA). Among 92 proteins in the Proseek Multiplex Oncology Iv2 panel, 87 were above the limit of detection (LOD) in liquid plasma and 56 among 92 above LOD in plasma applied to FTA cards. Washing and protein elution protocols were compared to identify an optimal method. Liquid-based cytology samples showed a lower number of proteins above LOD than FTA cards with vaginal fluid samples applied. Our results demonstrate that samples applied to the indicating FTA elute micro card™ are amendable to protein analyses, given that a sensitive protein detection assay is used. The results imply that biological samples applied to FTA cards can be used for DNA, RNA and protein detection.