Sample records for plasma microinstabilities

  1. Kinetic studies of microinstabilities in toroidal plasmas: Simulation and theory

    SciTech Connect

    Lee, W.W.; Haham, T.S.; Parker, S.E.; Perkins, F.W.; Rath, S.; Rewoldt, G.; Reynders, J.V.W.; Santoro, R.A.; Tang, W.M.

    1992-12-01

    A comprehensive program for the development and use of particle simulation techniques for solving the gyrokinetic Vlasov-Maxwell equations on massively parallel computers has been carried out at Princeton Plasma Physics Laboratory. This is a key element of our ongoing theoretical efforts to systematically investigate physics issues vital to understanding tokamak plasmas. In this paper, our focus is on spatial-gradient-driven microinstabilities. Their importance is supported by the recent progress in achieving a physics-based understanding of anomalous transport in toroidal systems which has been based on the proposition that these drift-type electrostatic modes dependent on ion temperature gradient (ITG) and trapped particle effects are dominant in the bulk (``confinement``) region. Although their presence is consistent with a number of significant confinement trends, results from high temperature tokamaks such as TFTR have highlighted the need for better insight into the nonlinear properties of such instabilities in long-mean-free-path plasmas. In addressing this general issue, we report important new results including (i) the first fully toroidal 3D gyrokinetic simulation of ITG modes and (ii) realistic toroidal eigenmode calculations demonstrating the unique capability to deal with large scale kinetic behavior extending over many rational surfaces. The effects of ITG modes (iii) on the inward pinch of impurities in 3D slab geometry and (iv) on the existence of microtearing modes in 2D slab are also discussed. Finally, (v) sheared toroidal flow effects on trapped-particle modes are presented.

  2. Kinetic studies of microinstabilities in toroidal plasmas: Simulation and theory

    SciTech Connect

    Lee, W.W.; Haham, T.S.; Parker, S.E.; Perkins, F.W.; Rath, S.; Rewoldt, G.; Reynders, J.V.W.; Santoro, R.A.; Tang, W.M.

    1992-12-01

    A comprehensive program for the development and use of particle simulation techniques for solving the gyrokinetic Vlasov-Maxwell equations on massively parallel computers has been carried out at Princeton Plasma Physics Laboratory. This is a key element of our ongoing theoretical efforts to systematically investigate physics issues vital to understanding tokamak plasmas. In this paper, our focus is on spatial-gradient-driven microinstabilities. Their importance is supported by the recent progress in achieving a physics-based understanding of anomalous transport in toroidal systems which has been based on the proposition that these drift-type electrostatic modes dependent on ion temperature gradient (ITG) and trapped particle effects are dominant in the bulk ( confinement'') region. Although their presence is consistent with a number of significant confinement trends, results from high temperature tokamaks such as TFTR have highlighted the need for better insight into the nonlinear properties of such instabilities in long-mean-free-path plasmas. In addressing this general issue, we report important new results including (i) the first fully toroidal 3D gyrokinetic simulation of ITG modes and (ii) realistic toroidal eigenmode calculations demonstrating the unique capability to deal with large scale kinetic behavior extending over many rational surfaces. The effects of ITG modes (iii) on the inward pinch of impurities in 3D slab geometry and (iv) on the existence of microtearing modes in 2D slab are also discussed. Finally, (v) sheared toroidal flow effects on trapped-particle modes are presented.

  3. Towards a realistic prediction of the solar wind plasma microinstabilities

    NASA Astrophysics Data System (ADS)

    Lazar, Marian; Poedts, Stefaan; Schlickeiser, Reinhard

    2015-04-01

    Two scenarios are known for the origin of the field and density fluctuations observed in the solar wind. Thus, the fluctuations can be induced at different scales, either locally and self-consistently by the kinetic anisotropy of plasma particles, or can be injected at larger scales closer to the Sun and then decayed and transported by the super-Alfvénic wind. In both scenarios, details of the plasma microstates - the particle velocity distributions (VDFs), are needed for an accurate description of the fluctuations. In-situ measurements reveal nonequilibrium plasmas with VDFs comprising two major components, a Maxwellian (thermal) core and a less dense but hotter suprathermal halo with a power-law distribution best described by the Kappa models, and the field-aligned strahl as a third component, usually assimilated with the suprathermal populations. Despite this observational evidence, the existing attempts to parameterize the observed (anisotropic) distributions and the supporting fluctuations and instabilities are limited to simplified models, which either ignore the suprathermal halo or just minimize the role of the core assuming it cold, or artificially incorporates both the core and halo in a single, global Kappa that is nearly Maxwellian at low speeds and decreases smoothly as a power law at high speeds. Simplified models imply a reduced number of plasma parameters and are convenient computationally, but they omit important kinetic effects of the plasma particles. Realistic models imply a large number of parameters, especially in the presence of kinetic anisotropies, and make it difficult to identify the instability conditions. However, in a recent endeavor to investigate nonindealized situations when both the core and halo temperatures are finite and anisotropic, we found computationally tractable such a complex model that combines an anisotropic bi-Maxwellian core and an anisotropic bi-Kappa halo. This model is relevant for the slow wind conditions and, in general in the solar wind at large heliocentric distances, e.g., > 1 AU, when the field-aligned strahl is significantly diminished. Here we present our first results for the particular case of the EM cyclotron instabilities driven by the electron temperature anisotropy, and provide a contrasting picture with the idealized models. Perspectives are also discussed to apply the same model and stability/dispersion analysis for a realistic characterization of the complementary instabilities, e.g., firehose, mirror, etc., of interest in space plasma physics.

  4. Microinstabilities in weak density gradient tokamak systems

    SciTech Connect

    Tang, W.M.; Rewoldt, G.; Chen, L.

    1986-04-01

    A prominent characteristic of auxiliary-heated tokamak discharges which exhibit improved (''H-mode type'') confinement properties is that their density profiles tend to be much flatter over most of the plasma radius. Depsite this favorable trend, it is emphasized here that, even in the limit of zero density gradient, low-frequency microinstabilities can persist due to the nonzero temperature gradient.

  5. Toroidal microinstability studies of high temperature tokamaks

    SciTech Connect

    Rewoldt, G.; Tang, W.M.

    1989-07-01

    Results from comprehensive kinetic microinstability calculations are presented showing the effects of toroidicity on the ion temperature gradient mode and its relationship to the trapped-electron mode in high-temperature tokamak plasmas. The corresponding particle and energy fluxes have also been computed. It is found that, although drift-type microinstabilities persist over a wide range of values of the ion temperature gradient parameter /eta//sub i/ /equivalent to/ (dlnT/sub i//dr)/(dlnn/sub i//dr), the characteristic features of the dominant mode are those of the /eta//sub i/-type instability when /eta//sub i/ > /eta//sub ic/ /approximately/1.2 to 1.4 and of the trapped-electron mode when /eta//sub i/ < /eta//sub ic/. 16 refs., 7 figs.

  6. Microinstability Studies for the Large Helical Device

    SciTech Connect

    G. Rewoldt; L.-P. Ku; W.M. Tang; H. Sugama; N. Nakajima; K.Y. Watanabe; S. Murakami; H. Yamada; W.A. Cooper

    2002-01-28

    Fully kinetic assessments of the stability properties of toroidal drift modes have been obtained for cases for the Large Helical Device (LHD). This calculation employs the comprehensive linear microinstability code FULL, as recently extended for nonaxisymmetric systems. The code retains the important effects in the linearized gyrokinetic equation, using the lowest-order ''ballooning representation'' for high toroidal mode number instabilities in the electrostatic limit. These effects include trapped particles, FLR, transit and bounce and magnetic drift frequency resonances, etc., for any number of plasma species. Results for toroidal drift waves destabilized by trapped electrons and ion temperature gradients are presented, using numerically-calculated three-dimensional MHD equilibria. These are reconstructed from experimental measurements. Quasilinear fluxes of particles and energy for each species are also calculated. Pairs of LHD discharges with different magnetic axis positions and with and without pellet injection are compared.

  7. Finite-? simulation of microinstabilities

    SciTech Connect

    Startsev, Edward A.; Lee, W. W. [Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States)] [Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States)

    2014-02-15

    A new split-weight perturbative particle simulation scheme for finite-? plasmas in the presence of background inhomogeneities is presented. The scheme is an improvement over the original split-weight scheme, which splits the perturbed particle response into adiabatic and non-adiabatic parts to improve numerical properties. In the new scheme, by further separating out the adiabatic response of the particles associated with the quasi-static bending of the magnetic field lines in the presence of background inhomogeneities of the plasma, we are able to demonstrate the finite-? stabilization of drift waves and ion temperature gradient modes using a simple gyrokinetic particle code based on realistic fusion plasma parameters. However, for ?m{sub i}/m{sub e} ? 1, it becomes necessary to use the electron skin-depth as the grid size of the simulation to achieve accuracy in solving the resulting equations, unless special numerical arrangement is made for the cancelling of the two large terms on the either side of the governing equation. The proposed scheme is most suitable for studying shear-Alfvén physics in general geometry using straight field line coordinates for microturbulence and magnetic reconnection problems.

  8. Microinstability-based model for anomalous thermal confinement in tokamaks

    SciTech Connect

    Tang, W.M.

    1986-03-01

    This paper deals with the formulation of microinstability-based thermal transport coefficients (chi/sub j/) for the purpose of modelling anomalous energy confinement properties in tokamak plasmas. Attention is primarily focused on ohmically heated discharges and the associated anomalous electron thermal transport. An appropriate expression for chi/sub e/ is developed which is consistent with reasonable global constraints on the current and electron temperature profiles as well as with the key properties of the kinetic instabilities most likely to be present. Comparisons of confinement scaling trends predicted by this model with the empirical ohmic data base indicate quite favorable agreement. The subject of anomalous ion thermal transport and its implications for high density ohmic discharges and for auxiliary-heated plasmas is also addressed.

  9. Microinstability and internal impingement of the shoulder.

    PubMed

    Mistry, Alpesh; Campbell, Rob S D

    2015-07-01

    Internal impingement refers to entrapment of the rotator cuff and capsulolabral structures between the glenoid and humeral head in certain positions of the shoulder. This may be a normal physiologic phenomenon. However, it may occur as a pathologic process, especially in sports with repetitive overhead activity. The two types of internal impingement are posterosuperior and anterosuperior, with established radiologic manifestations. These conditions were initially thought to be due to repetitive mechanical entrapment. Subsequent observational studies have led to the concepts of microinstability and glenohumeral internal rotatory deficit. Controversy remains regarding the exact pathophysiology, reflected in the variable outcomes in the treatment of these syndromes. The reporting radiologist must be aware of the constellation of image findings to alert the referring physician to the possibility of microinstability and internal impingement. PMID:26021588

  10. Core micro-instability analysis of JET hybrid and baseline discharges with carbon wall

    E-print Network

    Moradi, S; Voitsekhovitch, I; Garzotti, L; Bourdelle, C; Pueschel, M J; Lupelli, I; Romanelli, M; contributors, the JET-EFDA

    2014-01-01

    The core micro-instability characteristics of hybrid and baseline plasmas in a selected set of JET plasmas with carbon wall are investigated through local linear and non-linear and global linear gyro-kinetic simulations with the GYRO code [J. Candy and E. Belli, General Atomics Report GA-A26818 (2011)]. In particular, we study the role of plasma pressure on the micro-instabilities, and scan the parameter space for the important plasma parameters responsible for the onset and stabilization of the modes under experimental conditions. We find that a good core confinement due to strong stabilization of the micro-turbulence driven transport can be expected in the hybrid plasmas due to the stabilizing effect of the fast ion pressure that is more effective at the low magnetic shear of the hybrid discharges. While parallel velocity gradient destabilization is important for the inner core, at outer radii the hybrid plasmas may benefit from a strong quench of the turbulence transport by $\\mathbf{E}\\times\\mathbf{B}$ rot...

  11. Comparison of Linear Microinstability Calculations of Varying Input Realism

    SciTech Connect

    G. Rewoldt

    2003-09-08

    The effect of varying ''input realism'' or varying completeness of the input data for linear microinstability calculations, in particular on the critical value of the ion temperature gradient for the ion temperature gradient mode, is investigated using gyrokinetic and gyrofluid approaches. The calculations show that varying input realism can have a substantial quantitative effect on the results.

  12. Current-driven microinstabilities in a neutral sheet

    Microsoft Academic Search

    D. Winske

    1981-01-01

    Computer simulation is used to investigate current-driven microinstabilities in a simple reversed field (neutral sheet) configuration. A long wavelength, predominantly electromagnetic, instability develops at the reversal point as a consequence of the lower hybrid drift instability, which is excited away from the reversal point where the density gradients are steep. The resulting anomalous resistivity is much smaller at the null

  13. Current-driven microinstabilities in a neutral sheet

    NASA Astrophysics Data System (ADS)

    Winske, D.

    1981-06-01

    Computer simulation is used to investigate current-driven microinstabilities in a simple reversed field (neutral sheet) configuration. A long wavelength, predominantly electromagnetic, instability develops at the reversal point as a consequence of the lower hybrid drift instability, which is excited away from the reversal point where the density gradients are steep. The resulting anomalous resistivity is much smaller at the null point.

  14. Dynamics and microinstabilities at perpendicular collisionless shock: A comparison of large-scale two-dimensional full particle simulations with different ion to electron mass ratio

    SciTech Connect

    Umeda, Takayuki, E-mail: umeda@stelab.nagoya-u.ac.jp; Kidani, Yoshitaka [Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya 464-8601 (Japan)] [Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya 464-8601 (Japan); Matsukiyo, Shuichi, E-mail: matsukiy@esst.kyushu-u.ac.jp [Earth System Science and Technology, Kyushu University, Kasuga 816-8580 (Japan)] [Earth System Science and Technology, Kyushu University, Kasuga 816-8580 (Japan); Yamazaki, Ryo, E-mail: ryo@phys.aoyama.ac.jp [Department of Physics and Mathematics, Aoyama Gakuin University, Sagamihara 252-5258 (Japan)] [Department of Physics and Mathematics, Aoyama Gakuin University, Sagamihara 252-5258 (Japan)

    2014-02-15

    Large-scale two-dimensional (2D) full particle-in-cell (PIC) simulations are carried out for studying the relationship between the dynamics of a perpendicular shock and microinstabilities generated at the shock foot. The structure and dynamics of collisionless shocks are generally determined by Alfven Mach number and plasma beta, while microinstabilities at the shock foot are controlled by the ratio of the upstream bulk velocity to the electron thermal velocity and the ratio of the plasma-to-cyclotron frequency. With a fixed Alfven Mach number and plasma beta, the ratio of the upstream bulk velocity to the electron thermal velocity is given as a function of the ion-to-electron mass ratio. The present 2D full PIC simulations with a relatively low Alfven Mach number (M{sub A} ? 6) show that the modified two-stream instability is dominant with higher ion-to-electron mass ratios. It is also confirmed that waves propagating downstream are more enhanced at the shock foot near the shock ramp as the mass ratio becomes higher. The result suggests that these waves play a role in the modification of the dynamics of collisionless shocks through the interaction with shock front ripples.

  15. Experimental investigation of collisionless electron-electron microinstabilities. Final technical report for the period August 1, 1997-October 31, 2000

    SciTech Connect

    Scime, Earl E.

    2000-12-11

    This is the final report for the Office of Fusion Energy sponsored project entitled, "Experimental Investigation of Collisionless Electron-Electron Microinstabilities." The report summarizes the scientific and human resource development accomplishments supported through this project.

  16. Collisionless microinstabilities in stellarators. I. Analytical theory of trapped-particle modes

    SciTech Connect

    Helander, P.; Proll, J. H. E.; Plunk, G. G. [Max-Planck-Institut für Plasmaphysik, EURATOM Association, 17491 Greifswald (Germany) [Max-Planck-Institut für Plasmaphysik, EURATOM Association, 17491 Greifswald (Germany); Max-Planck/Princeton Research Center for Plasma Physics, 17491 Greifswald (Germany)

    2013-12-15

    This is the first in a series of papers about collisionless, electrostatic micro-instabilities in stellarators, with an emphasis on trapped-particle modes. It is found that, in so-called maximum-J configurations, trapped-particle instabilities are absent in large regions of parameter space. Quasi-isodynamic stellarators have this property (approximately), and the theory predicts that trapped electrons are stabilizing to all eigenmodes with frequencies below the electron bounce frequency. The physical reason is that the bounce-averaged curvature is favorable for all orbits, and that trapped electrons precess in the direction opposite to that in which drift waves propagate, thus precluding wave-particle resonance. These considerations only depend on the electrostatic energy balance and are independent of all geometric properties of the magnetic field other than the maximum-J condition. However, if the aspect ratio is large and the instability phase velocity differs greatly from the electron and ion thermal speeds, it is possible to derive a variational form for the frequency showing that stability prevails in a yet larger part of parameter space than what follows from the energy argument. Collisionless trapped-electron modes should therefore be more stable in quasi-isodynamic stellarators than in tokamaks.

  17. plasmas

    NASA Astrophysics Data System (ADS)

    Zhang, H. Y.; Jin, C. G.; Yang, Y.; Ye, C.; Zhuge, L. J.; Wu, X. M.

    2014-12-01

    As-deposited HfO2 films were modified by CHF3, C4F8, and mixed C4F8/O2 plasmas in a dual-frequency capacitively coupled plasma chamber driven by radio frequency generators of 60 MHz as the high frequency (HF) source and 2 MHz as the low frequency source (60/2 MHz). The influences of various surface plasma treatments under CHF3, C4F8, and C4F8/O2 were investigated in order to understand the chemical and structural changes in thin-film systems, as well as their influence on the electrical properties. Fluorine atoms were incorporated into the HfO2 films by either CHF3 or C4F8 plasma treatment; meanwhile, the C/F films were formed on the surface of the HfO2 films. The formation of C/F layers decreased the k value of the gate stacks because of its low dielectric constant. However, the addition of O2 gas in the discharge gases suppressed the formation of C/F layers. After thermal annealing, tetragonal HfO2 phase was investigated in both samples treated with CHF3 and C4F8 plasmas. However, the samples treated with O-rich plasmas showed monoclinic phase, which indicated that the addition of O plasmas could influence the Hf/O ratio of the HfO2 films. The mechanism of the t-HfO2 formation was attributed to oxygen insufficiency generated by the incorporation of F atoms. The capacitors treated with C4F8/O2 plasmas displayed the highest k value, which ascribed that the C/F layers were suppressed and the tetragonal phase of HfO2 was formed. Good electrical properties, especially on the hysteresis voltage and frequency dispersion, were obtained because the bulk traps were passivated by the incorporation of F atoms. However, the H-related traps were generated during the CHF3 plasma treatments, which caused the performance degradation. All the treated samples showed lower leakage current density than the as-deposited HfO2 films at negative bias due to the reduced trap-assisted tunneling by the incorporation of F to block the electrons transferring from metal electrode to the trap level.

  18. Studies of instability and transport in sheared-slab plasmas with very weak magnetic shear

    NASA Astrophysics Data System (ADS)

    Dong, J. Q.; Zhang, Y. Z.; Mahajan, S. M.

    1997-09-01

    Ion temperature gradient (ITG or ?i) driven microinstabilities are studied, using kinetic theory, for tokamak plasmas with very weak (positive or negative) magnetic shear (VWS). The gradient of magnetic shear as well as the effects of parallel and perpendicular velocity shear (v?' and vE') are included in the defining equations. Two eigenmodes: the double (D) and the global (G) are found to coexist. Parametric dependence of these instabilities, and of the corresponding quasilinear transport is systematically analyzed. It is shown that, in VWS plasmas, a parallel velocity shear (PVS) may stabilize or destabilize the modes, depending on the individual as well as the relative signs of PVS and of the gradient of magnetic shear. The quasilinear transport induced by the instabilities may be significantly reduced with PVS in VWS plasmas. The vE' values required to completely suppress the instabilities are much lower in VWS plasmas than they are in normal plasmas. Possible correlations with tokamak experiments are discussed.

  19. Ion microinstability at the outer sloshing-ion turning point of the tandem mirror experiment upgrade (TMX-U)

    SciTech Connect

    Berzins, L.V.; Casper, T.A.

    1987-09-28

    Since the start of TMX-U operations we have observed weak oscillations with a frequency approximately twice the ion-cyclotron frequency at the end-cell midplane. Recent results show that this instability is driven at the sloshing-ion outer turning point. We find that the sloshing-ion lifetime scales inversely with the instability amplitude. The sensitivity of this instability to the cold-ion density shows that this is a loss-cone instability. These results have important implications for mirror fusion experiments as well as solar and space plasmas.

  20. Numerical simulations of energy transfer in counter-streaming plasmas

    NASA Astrophysics Data System (ADS)

    Davis, S. P.; Capdessus, R.; d'Humières, E.; Jequier, S.; Andriyash, I.; Tikhonchuk, V.

    2013-03-01

    Collisionless shock formation is investigated with large scale fully electromagnetic two-dimensional Particle-in-Cell numerical simulations. Two plasmas are colliding in the center of mass reference frame at sub-relativistic velocities. Their interaction leads to collisionless stochastic electron heating, ion slowing down and formation of a shock front. We focus here on the initial stage of evolution where electron heating is due to the Weibel-like micro-instability driven by the high-speed ion flow. A two stage process is described in the detailed analysis of our simulation results. Filament generation, followed by turbulent mixing, constitute the dominant mechanism for energy repartition. The global properties are illustrated by examination of single filament evolution in terms of energy/particle density and fields.

  1. Adiabatic electron response and solitary wave generation by trapped particle nonlinearity in a hydrogen plasma

    SciTech Connect

    Mandal, Debraj; Sharma, Devendra [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India)

    2014-10-15

    The finite amplitude ion acoustic waves that trap electrons modify the structure of the evolving nonlinear soliton solutions. In the numerical simulations, self-consistently generated solitary waves are studied that emerge as a result of a current driven microinstability growing the ion acoustic mode in a collisionless Vlasov plasma. The growth saturates as a result of nonlinear effects governed by a combination of nonlinearities originating from the hydrodynamic model and kinetic particle trapping effects. The resulting solitary waves also coexist with a finite current and an electron plasma wave capable of perturbing the trapping potential. The results of multiscale simulation are analyzed and characterized following the kinetic prescription of undamped trapped particle mode in the form of phase space vortex solutions that are generalized form of Sagdeev's solitons and obey the solutions of a modified Korteweg-de Vries equation, accounting for a stronger nonlinearity originating from the electron trapping.

  2. Instability of a current-carrying finite-beta collisional plasma

    NASA Astrophysics Data System (ADS)

    Choueiri, E. Y.

    2001-12-01

    The microinstability of a cross-field current-carrying plasma in which the electron collisions are important on the time scale of the oscillations and can be modeled with a Bhatnagar-Gross-Krook operator is studied using linearized kinetic theory under conditions of finite electron beta. The finiteness of beta allows for coupling between electrostatic and electromagnetic modes and necessitates dealing with the entire dispersion tensor. Fundamental features of the resulting instability are identified and contrasted with those found in previous studies of the lower hybrid current-driven instability in which either collisions or finite-beta effects were neglected. As beta increases, collisions play a more important role in destabilization, alter the character and extent of electromagnetic coupling, shift the instability to more perpendicular modes, and lead to a recapturing of some of the fluidlike properties the modes have in the electrostatic limit in contrast with their highly kinetic character in the collisionless limit.

  3. Trapped ion mode in toroidally rotating plasmas

    SciTech Connect

    Artun, M.; Tang, W.M.; Rewoldt, G.

    1995-04-01

    The influence of radially sheared toroidal flows on the Trapped Ion Mode (TIM) is investigated using a two-dimensional eigenmode code. These radially extended toroidal microinstabilities could significantly influence the interpretation of confinement scaling trends and associated fluctuation properties observed in recent tokamak experiments. In the present analysis, the electrostatic drift kinetic equation is obtained from the general nonlinear gyrokinetic equation in rotating plasmas. In the long perpendicular wavelength limit k{sub {tau}}{rho}{sub bi} {much_lt} 1, where {rho}{sub bi} is the average trapped-ion banana width, the resulting eigenmode equation becomes a coupled system of second order differential equations nmo for the poloidal harmonics. These equations are solved using finite element methods. Numerical results from the analysis of low and medium toroidal mode number instabilities are presented using representative TFTR L-mode input parameters. To illustrate the effects of mode coupling, a case is presented where the poloidal mode coupling is suppressed. The influence of toroidal rotation on a TFTR L-mode shot is also analyzed by including a beam species with considerable larger temperature. A discussion of the numerical results is presented.

  4. Pulsed currents carried by whistlers. IX. {bold {ital In situ}} measurements of currents disrupted by plasma erosion

    SciTech Connect

    Urrutia, J.M.; Stenzel, R.L. [Department of Physics and Astronomy, University of California, Los Angeles, California 90095-1547 (United States)] [Department of Physics and Astronomy, University of California, Los Angeles, California 90095-1547 (United States)

    1997-01-01

    In a magnetized laboratory plasma described in the companion paper [Stenzel and Urrutia, Phys. Plasmas {bold 4}, 26 (1997)], a large positive voltage step (V{gt}kT{sub e}/e) is applied to electrodes. The current front propagates in the whistler mode in the parameter regime of electron magnetohydrodynamics. The topology of the current density is that of nested helices. Large transient currents in excess of the electron saturation current can be drawn. A transient radial electric field associated with the current rise, excites a compressional, large amplitude, radially outgoing sound wave, which leaves the current channel depleted of plasma. The current collapses due to the density erosion. Electric field reversal excites a rarefaction wave which leads to a partial density and current recovery. Periodic plasma inflow and outflow cause the current to undergo strong relaxation oscillations at a frequency determined by the electrode diameter and the sound speed. In addition, a broad spectrum of microinstabilities is observed in regions of high current density. For drift velocities approaching the thermal speed, the spectrum extends beyond the ion plasma frequency ({omega}{sub pi}) up to the electron plasma frequency ({omega}{sub pe}). Correlation measurements above {omega}{sub pi} reveal modes propagating along the electron drift at speeds above the sound speed but well below the electron drift speed. {copyright} {ital 1997 American Institute of Physics.}

  5. Currents between tethered electrodes in a magnetized laboratory plasma

    SciTech Connect

    Stenzel, R.L.; Urrutia, J.M. (Univ. of California, Los Angeles (United States))

    1990-05-01

    Laboratory experiments on important plasma physics issues of electrodynamic tethers are performed. These include current propagation, formation of wave wings, limits of current collection, nonlinear effects and instabilities, charging phenomena, and characteristics of transmission lines in plasmas. The current system is established with a small electron-emitting hot cathode tethered to an electron-collecting anode, both movable across the magnetic field and energized by potential differences up to V {approx} 100 kT{sub e}/e. The total current density in space and time is obtained from complete measurements of the perturbed magnetic field. J = {gradient} {times} B(r,t)/{mu}{sub 0}. The fast spacecraft motion is reproduced in the laboratory by moving the tethered electrodes in small increments, applying delayed current pulses, and reconstructing the net field by a linear superposition of locally emitted wavelets. With this technique, the small-amplitude dc current pattern is shown to form whistler wings at each electrode instead of the generall accepted Alfven wings. For the beam electrode, the whistler wing separates from the field-aligned beam which carries no net current. Large-amplitude return currents to a stationary anode generate current-driven microinstabilities, parallel electric fields, ion depletions, current disruptions, and time-varying electrode charging. At appropriately high potentials and neutral densities, excess neutrals are ionized near the anode. The anode sheath emits high-frequency electron transit-time oscillations at the sheath-plasma resonance. The beam generates Langmuir turbulence, ion sound turbulence, electron heating, space charge fields, and Hall currents. An insulated, perfectly conducting transmission line embedded in the plasma becomes lossy due to excitation of whistler waves and magnetic field diffusion effects.

  6. Electron-Ion Streaming Instabilities of AN Electromagnetically Accelerated Plasma.

    NASA Astrophysics Data System (ADS)

    Choueiri, Edgar Yazid

    This dissertation addresses the linear and nonlinear plasma physics associated with electron-ion streaming instabilities of an electromagnetically accelerated plasma. Specifically, the microinstabilities and related wave-particle transport in the working plasma of the Lorentz force accelerator (LFA) or magnetoplasmadynamic (MPD) thruster are investigated. The stability analysis required the derivation of a general dispersion tensor from kinetic theory for a magnetoactive plasma including the effects of a cross-field current, collisions, flowing plasma and arbitrary polarization. The inclusion of the last effect was necessitated by the finite beta (ratio of thermal to magnetic pressures) of such plasmas. While analytical solutions were only possible for some simplified situations the full electromagnetic problem including collisions required detailed numerical studies to reveal the nature, dependences and trends of the thresholds, frequencies, temporal and spatial growth rates, phase velocities and polarization of the unstable modes. The dominant instability was found to be the lower hybrid current-driven instability (LHCDI), which is the finite-beta generalization of the modified two-stream instability (MTSI). The effects of collisions, spatial evolution and plasma beta on the instability were studied parametrically. While the resulting dispersion relations describing the unstable waves in their linear growth stage were helpful to the design and interpretation of active wave injection experiments, the ultimate goal was an assessment of the importance of microturbulent transport namely the anomalous resistivity and heating rates engendered by the saturated unstable waves. For this purpose, finite -beta expressions for the anomalous resistivity and the anomalous heating rates of both ions and electrons were derived within the framework of a quasilinear weak turbulence formalism. Using the potential representation of the dielectric tensor it was possible to express the anomalous rates as an electrostatic contribution and a finite-beta (electromagnetic) correction. It was demonstrated through calculations in the region of parameter-space typical of the LFA plasma that the finite-beta correction can be significant and that the dominance of anomalous transport over classical dissipation is conditioned by large values of the electron Hall parameter. If the instabilities saturate by trapping the ions, the calculations show that significant enhancement to the local resistivity of the plasma can result in regions of low collisionality leading to the substantial thermalization, which would adversely impact the efficiency of plasma acceleration.

  7. Study of Fast Reconnection in Laboratory Plasmas

    NASA Astrophysics Data System (ADS)

    Yamada, M.; Ji, H.; Terry, S.; Kulsrud, R.

    2002-12-01

    With abundant data from space satellites and the recently developed laboratory experiments, there exist many opportunities for collaborative study between space and laboratory experimental research. In this talk, we highlight the recent laboratory experimental data from the MRX device [1] in comparison with the space observations [2] as well as with the recent numerical simulations[3] addressing a major question why the observed reconnection rates are much faster than predictions by the classical theories, such as the Sweet-Parker model. There exist two leading theories for the underlying physics: one based on laminar 2D structures due to the Hall terms in the generalized Ohm's law and another based on resistivity enhancement (or the so-called anomalous resistivity) due to the inherently 3D micro-instabilities. Experimental efforts are under way to study both mechanisms in MRX, where the fast reconnection rates have been regularly observed in the low collisionality regime. A fine structure probe with spatial resolution of 1 mm (2-3 electron skin depth) is being installed. Also a special focus will be put on the electrostatic and magnetic turbulence which have recently been identified in the neutral sheet. The details of the characteristics of the turbulence measured by Hodogram probe and internal pick-up probes will be presented along with theoretical interpretations and discussions on its relation with the observed fast reconnection in space. Work supported by DOE, NASA And NSF. 1. M. Yamada et al., Phys. Plasmas 4, 1936, (1997) 2. F. Mozer et al, Phys. Rev. Letts. 15002, 1, (2002) 3. M.A. Shay et al J. Geophys. Res. 103, 9165 (1998)

  8. Electrostatic Microinstabilities within the Electron Diffusion Layer

    NASA Astrophysics Data System (ADS)

    Jara-Almonte, J.; Daughton, W.; Ji, H.; Yamada, M.

    2013-10-01

    Both numerical simulations and laboratory experiments have extensively studied the electron skin-depth scale structure of the electron diffusion layer, but neither have fully resolved both the scale-seperation and physics on scales between the Debye length and the skin-depth. Here, the first fully kinetic 2D simulations of anti-parallel magnetic reconnection at realistic electron temperatures (c /vthe = 64 and ?pe /?e = 32) are presented. Macroscopic features such as the reconnection rate or layer width are found to be insensitive to the electron temperature. When the electron temperature becomes sufficiently low, the electron diffusion layer becomes unstable to electrostatic instabilities involving multiple streaming populations near the X-line. This leads to multiple electron holes within the electron diffusion layer which interact non-linearly to generate turbulence which may be important in understanding the electron heating within the diffusion layer observed in experiments. Both numerical simulations and laboratory experiments have extensively studied the electron skin-depth scale structure of the electron diffusion layer, but neither have fully resolved both the scale-seperation and physics on scales between the Debye length and the skin-depth. Here, the first fully kinetic 2D simulations of anti-parallel magnetic reconnection at realistic electron temperatures (c /vthe = 64 and ?pe /?e = 32) are presented. Macroscopic features such as the reconnection rate or layer width are found to be insensitive to the electron temperature. When the electron temperature becomes sufficiently low, the electron diffusion layer becomes unstable to electrostatic instabilities involving multiple streaming populations near the X-line. This leads to multiple electron holes within the electron diffusion layer which interact non-linearly to generate turbulence which may be important in understanding the electron heating within the diffusion layer observed in experiments. This research is supported by DoE Contract Number DE-AC02-09CH11466 and by the Center for Magnetic Self-Organization (CMSO).

  9. Plasma Instability Growth Rates in the F-Region Cusp Ionosphere

    NASA Astrophysics Data System (ADS)

    Moen, J. I.; Daabakk, Y.; Oksavik, K.; Clausen, L.; Bekkeng, T. A.; Abe, T.; Saito, Y.; Baddeley, L. J.; Lorentzen, D. A.; Sigernes, F.; Yeoman, T. K.

    2014-12-01

    There are at least two different micro-instability processes that applies to the F-region cusp/polar cap ionosphere. These are the Gradient Drift Instability (GDI) and the Kelvin Helmholtz Instability (KHI). Due to space weather effects on radio communication and satellite signals it is of practical interest to assess the relative importance of these two instability modes and to quantify their growth rates. The Investigation of Cusp Irregularities (ICI) rocket program has been developed to investigate these plasma instabilities and formation scintillation irregularities. High resolution measurements are critical to get realistic quantities on the growth rates. The results achieved so far demonstrates that cusp ionosphere precipitation can give rise to km scale plasma structures on which grow rates are down to a few tens of seconds compared to earlier measures of ten minutes based on ground observations. This has to do with the spatial resolution required for these measurements. Growth rates for the KHI instability is found to be of the same order, which is consistent with growth rates calculated from the EISCAT Svalbard Radar. I.e. both instability modes can be highly efficient in the cusp ionosphere.

  10. Numerical simulations of anisotropic plasmas using a modified ZEUS-MP

    NASA Astrophysics Data System (ADS)

    Chandran, Benjamin; Tangri, Varun; Sarkar, Aveek; Perez, Jean; Sharma, Prateek

    2012-10-01

    Three dimensional linear and nonlinear simulations of collisionless one-fluid plasmas with pressure anisotropy are presented using the Chew- Goldberger-Low (CGL-MHD) and double-isothermal models. For this purpose, the code ZEUS-MP [J. C. Hayes et. al. The APJ Supplement Series 165 (2006) 188.] has been modified. Major modifications include a changed method of characteristics, new compressive and non-compressive forces, and a ``hard wall'' limit on pressure anisotropy that is intended to mimic the effects of plasma micro-instabilities that limit the temperature anisotropy. For purposes of validation, more than 100 test simulations of linear waves (Alfven, slow and fast), instabilities (firehose and mirror) and nonlinear vortices (Orszag-Tang) are presented for a number of initial conditions and parameters. Finally, this model is used to investigate the way that Alfven-wave turbulence leads to a spreading of the temperature-anisotropy probability distribution in the solar wind. Analysis is completed with a detailed analysis of the fluctuation data.

  11. Improved Confinement in Impurity-Seeded Plasmas in JT-60U and TFTR

    NASA Astrophysics Data System (ADS)

    Hill, K. W.; Ernst, D. R.; Park, H. K.; Rewoldt, G.; Synakowski, E. J.; Taylor, G.; Bush, C. E.; Asakura, N.; Kubo, H.; Sakurai, S.; Itami, K.; Tamai, H.; Konoshima, S.; Higashijima, S.; Shimizu, K.; Shirai, H.; JT-60u Team

    2000-10-01

    Improved energy confinement in impurity-seeded plasmas has been observed on several tokamaks, offering the possibility of high confinement at high density and reduced power to the wall. We analyze and compare impurity-seeded plasmas in TFTR and JT-60U, with a goal of understanding the improved confinement. In JT-60U ELMy H-modes with Ar puffing at n_e^GW = 0.7, H = 1.4 has been achieved, about 40% higher than with D2 puffing alone. In TFTR supershots at NBI power Pb ~ 16 MW, \\chii and \\chi_? decreased with Kr and Xe puffing; the ITG mode was stabilized by Kr puffing. At high power (Pb > 28 MW) with Kr injection, confinement and fusion power were improved, and carbon blooms were eliminated. Analysis includes thermal transport by the TRANSP and TOPICS codes, microinstability predictions by FULL and GS2, E× B shearing rate by TRV, and impurity transport and radiated power distributions by MIST and IMPACT.

  12. Dusty plasmas

    Microsoft Academic Search

    Vladimir E Fortov; Aleksei G Khrapak; Sergei A Khrapak; Vladimir I Molotkov; Oleg F Petrov

    2004-01-01

    The properties of dusty plasmas — low-temperature plasmas containing charged macroparticles — are considered. The most important elementary processes in dusty plasmas and the forces acting on dust particles are investigated. The results of experimental and theoretical investigations of different states of strongly nonideal dusty plasmas — crystal-like, liquid-like, gas-like — are summarized. Waves and oscillations in dusty plasmas, as

  13. Numerical simulation of non-equilibrium plasma flow in a cylindrical MPD thruster using a high-order flux-difference splitting method

    NASA Astrophysics Data System (ADS)

    Ahangar, Mahdy; Ebrahimi, Reza; Shams, Mehrzad

    2014-10-01

    A two-dimensional axisymmetric computational algorithm is developed to simulate the plasma flow field in a self-field MPD thruster, in order to determine the flow behavior and the electromagnetic characteristics distribution. The convective flux vector is computed by using Roe's scheme in combination with Powell's eigensystem technique, and a new modified MUSCL technique called OMUSCL2 is employed to obtain the stable high-accuracy solution. Madrane-Tadmor entropy correction is used to prevent unrealistic expansion shocks near the electrodes tips. To accurately capture the physics of plasma in the system, different physical-chemical sub-models including multi-level non-equilibrium ionization model, generalized Ohm's law for partially ionized plasma, micro-instabilities effects, two-temperature model, and a real equation of state are considered. Numerical results of plasma flow simulation in a cylindrical lab-scale thruster, with mass flow rate of 6 g/s and total discharge current of 8 kA, are presented and comparison with experimental data shows good agreement between the predicted and measured contours of enclosed current and electric potential. The estimated thrust is 16.34 N which exhibits less than 5% difference compared with measured value. Furthermore, this simulation properly predicts the experimentally observed argon jet structure.

  14. Plasma Medicine

    NASA Astrophysics Data System (ADS)

    Laroussi, M.; Kong, M. G.; Morfill, G.; Stolz, W.

    2012-05-01

    Foreword R. Satava and R. J. Barker; Part I. Introduction to Non-equilibrium Plasma, Cell Biology, and Contamination: 1. Introduction M. Laroussi; 2. Fundamentals of non-equilibrium plasmas M. Kushner and M. Kong; 3. Non-equilibrium plasma sources M. Laroussi and M. Kong; 4. Basic cell biology L. Greene and G. Shama; 5. Contamination G. Shama and B. Ahlfeld; Part II. Plasma Biology and Plasma Medicine: 6. Common healthcare challenges G. Isbary and W. Stolz; 7. Plasma decontamination of surfaces M. Kong and M. Laroussi; 8. Plasma decontamination of gases and liquids A. Fridman; 9. Plasma-cell interaction: prokaryotes M. Laroussi and M. Kong; 10. Plasma-cell interaction: eukaryotes G. Isbary, G. Morfill and W. Stolz; 11. Plasma based wound healing G. Isbary, G. Morfill and W. Stolz; 12. Plasma ablation, surgery, and dental applications K. Stalder, J. Woloszko, S. Kalghatgi, G. McCombs, M. Darby and M. Laroussi; Index.

  15. PIC Simulations of Hypersonic Plasma Instabilities

    NASA Astrophysics Data System (ADS)

    Niehoff, D.; Ashour-Abdalla, M.; Niemann, C.; Decyk, V.; Schriver, D.; Clark, E.

    2013-12-01

    The plasma sheaths formed around hypersonic aircraft (Mach number, M > 10) are relatively unexplored and of interest today to both further the development of new technologies and solve long-standing engineering problems. Both laboratory experiments and analytical/numerical modeling are required to advance the understanding of these systems; it is advantageous to perform these tasks in tandem. There has already been some work done to study these plasmas by experiments that create a rapidly expanding plasma through ablation of a target with a laser. In combination with a preformed magnetic field, this configuration leads to a magnetic "bubble" formed behind the front as particles travel at about Mach 30 away from the target. Furthermore, the experiment was able to show the generation of fast electrons which could be due to instabilities on electron scales. To explore this, future experiments will have more accurate diagnostics capable of observing time- and length-scales below typical ion scales, but simulations are a useful tool to explore these plasma conditions theoretically. Particle in Cell (PIC) simulations are necessary when phenomena are expected to be observed at these scales, and also have the advantage of being fully kinetic with no fluid approximations. However, if the scales of the problem are not significantly below the ion scales, then the initialization of the PIC simulation must be very carefully engineered to avoid unnecessary computation and to select the minimum window where structures of interest can be studied. One method of doing this is to seed the simulation with either experiment or ion-scale simulation results. Previous experiments suggest that a useful configuration for studying hypersonic plasma configurations is a ring of particles rapidly expanding transverse to an external magnetic field, which has been simulated on the ion scale with an ion-hybrid code. This suggests that the PIC simulation should have an equivalent configuration; however, modeling a plasma expanding radially in every direction is computationally expensive. In order to reduce the computational expense, we use a radial density profile from the hybrid simulation results to seed a self-consistent PIC simulation in one direction (x), while creating a current in the direction (y) transverse to both the drift velocity and the magnetic field (z) to create the magnetic bubble observed in experiment. The simulation will be run in two spatial dimensions but retain three velocity dimensions, and the results will be used to explore the growth of micro-instabilities present in hypersonic plasmas in the high-density region as it moves through the simulation box. This will still require a significantly large box in order to compare with experiment, as the experiments are being performed over distances of 104 ?De and durations of 105 ?pe-1.

  16. [Therapeutic plasmas].

    PubMed

    Schneider, T

    2012-11-01

    Three different therapeutic plasmas preparations are currently available in France and are issued by EFS to the hospitals: quarantine fresh frozen plasma, amotosalen-inactivated plasma and solvent/detergent-treated plasma. All these products insure a microbiological safety, an immunologic compatibility and a hemostatic potential for the patients. These plasmas are in accordance with the Guidelines established by the French Authorities (ANSM). PMID:22999855

  17. Plasma universe

    NSDL National Science Digital Library

    Space Science Institute

    2005-01-01

    This single-page reading underlines how abundant plasmas are in the universe. The reading, which is the final page in a tutorial about the plasma phase of matter, points out that understanding plasma is central to understanding what happens in the universe. Through space technologies, researchers have been able to study plasmas in areas like those shown in the images that illustrate this reading. One of the images shows plasma loops on the Sun. Copyright 2005 Eisenhower National Clearinghouse

  18. Cross-Scale Interactions between Electron and Ion Scale Turbulence in a Tokamak Plasma

    NASA Astrophysics Data System (ADS)

    Maeyama, S.; Idomura, Y.; Watanabe, T.-H.; Nakata, M.; Yagi, M.; Miyato, N.; Ishizawa, A.; Nunami, M.

    2015-06-01

    Multiscale gyrokinetic turbulence simulations with the real ion-to-electron mass ratio and ? value are realized for the first time, where the ? value is given by the ratio of plasma pressure to magnetic pressure and characterizes electromagnetic effects on microinstabilities. Numerical analysis at both the electron scale and the ion scale is used to reveal the mechanism of their cross-scale interactions. Even with the real-mass scale separation, ion-scale turbulence eliminates electron-scale streamers and dominates heat transport, not only of ions but also of electrons. Suppression of electron-scale turbulence by ion-scale eddies, rather than by long-wavelength zonal flows, is also demonstrated by means of direct measurement of nonlinear mode-to-mode coupling. When the ion-scale modes are stabilized by finite-? effects, the contribution of the electron-scale dynamics to the turbulent transport becomes non-negligible and turns out to enhance ion-scale turbulent transport. Damping of the ion-scale zonal flows by electron-scale turbulence is responsible for the enhancement of ion-scale transport.

  19. Cosmic plasma

    NASA Technical Reports Server (NTRS)

    Alfven, H.

    1981-01-01

    Attention is given to experimental and theoretical approaches to plasma physics, plasma phenomena in laboratory and space, field and particle aspects of plasmas, the present state of the classical theory, boundary conditions and circuit dependence, and cosmology. Electric currents in space plasmas are considered, taking into account dualism in physics, particle-related phenomena in plasma physics, magnetic field lines, filaments, local plasma properties and the circuit, electric double layers, field-aligned currents as 'cables', an expanding circuit, different types of plasma regions, the cellular structure of space, and the fine structure of active plasma regions. Other topics discussed are related to circuits, the theory of cosmic plasmas, the origin of the solar system, the coexistence of matter and antimatter, annihilation as a source of energy, the Hubble expansion in a Euclidean space, and a model for the evolution of the Metagalaxy.

  20. Dusty plasmas

    Microsoft Academic Search

    M. E. Jones; D. Winske; R. Keinigs; D. Lemons

    1996-01-01

    This is the final report of a three-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The objective of this project has been to develop a fundamental understanding of dusty plasmas at the Laboratory. While dusty plasmas are found in space in galactic clouds, planetary rings, and cometary tails, and as contaminants in plasma enhanced

  1. Amazing plasmas

    NSDL National Science Digital Library

    Space Science Institute

    2005-01-01

    A space weather site offers this tutorial about the state of matter called plasma. Animations, two games, and numerous enlargeable graphics are included in the tutorial. It presents information about what plasma is and where it is naturally found. The tutorial explains that understanding plasma and how it interacts with electric and magnetic fields is central to understanding much about our universe. In addition, one section of the tutorial discusses experimental fusion reactors in which man-made plasmas are used on earth. Plasma is the main type of matter in the universe, but it rarely occurs naturally on Earth because of the world's relatively cool temperatures. Copyright 2005 Eisenhower National Clearinghouse

  2. Dusty plasmas

    SciTech Connect

    Jones, M.E.; Winske, D.; Keinigs, R.; Lemons, D.

    1996-05-01

    This is the final report of a three-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The objective of this project has been to develop a fundamental understanding of dusty plasmas at the Laboratory. While dusty plasmas are found in space in galactic clouds, planetary rings, and cometary tails, and as contaminants in plasma enhanced fabrication of microelectronics, many of their properties are only partially understood. Our work has involved both theoretical analysis and self-consistent plasma simulations to understand basic properties of dusty plasmas related to equilibrium, stability, and transport. Such an understanding can improve the control and elimination of plasma dust in industrial applications and may be important in the study of planetary rings and comet dust tails. We have applied our techniques to the study of charging, dynamics, and coagulation of contaminants in plasma processing reactors for industrial etching and deposition processes and to instabilities in planetary rings and other space plasma environments. The work performed in this project has application to plasma kinetics, transport, and other classical elementary processes in plasmas as well as to plasma waves, oscillations, and instabilities.

  3. Earth plasmas

    NSDL National Science Digital Library

    Space Science Institute

    2005-01-01

    Fusion is the focus of this section of a tutorial about plasma, one of the four states of matter. This section deals with plasmas on Earth. There is little naturally-occurring plasma here because of the Earth's relatively cool (by universe standards) temperature, but human-made plasma is produced for industry and research purposes. The section explores the use of plasmas in experimental fusion reactors, pointing out three categories of significant unresolved issues that stand in the way of fusion becoming a viable energy source. The use of electromagnets to confine plasmas is discussed. Enlargeable images of fusion reactors are provided, and an explanation of the difference between fission and fusion is supplemented by animations of the two reaction types. Copyright 2005 Eisenhower National Clearinghouse

  4. Plasma valve

    DOEpatents

    Hershcovitch, Ady (Mount Sinai, NY); Sharma, Sushil (Hinsdale, IL); Noonan, John (Naperville, IL); Rotela, Elbio (Clarendon Hills, IL); Khounsary, Ali (Hinsdale, IL)

    2003-01-01

    A plasma valve includes a confinement channel and primary anode and cathode disposed therein. An ignition cathode is disposed adjacent the primary cathode. Power supplies are joined to the cathodes and anode for rapidly igniting and maintaining a plasma in the channel for preventing leakage of atmospheric pressure through the channel.

  5. Plasma accelerator

    DOEpatents

    Wang, Zhehui (Los Alamos, NM); Barnes, Cris W. (Santa Fe, NM)

    2002-01-01

    There has been invented an apparatus for acceleration of a plasma having coaxially positioned, constant diameter, cylindrical electrodes which are modified to converge (for a positive polarity inner electrode and a negatively charged outer electrode) at the plasma output end of the annulus between the electrodes to achieve improved particle flux per unit of power.

  6. Plasma universe

    NASA Technical Reports Server (NTRS)

    Alfven, H.

    1986-01-01

    Traditionally the views on the cosmic environent have been based on observations in the visual octave of the electromagnetic spectrum, during the last half-century supplemented by infrared and radio observations. Space research has opened the full spectrum. Of special importance are the X-ray-gamma-ray regions, in which a number of unexpected phenomena have been discovered. Radiations in these regions are likely to originate mainly from magnetised cosmic plasmas. Such a medium may also emit synchrotron radiation which is observable in the radio region. If a model of the universe is based on the plasma phenomena mentioned it is found that the plasma universe is drastically different from the traditional visual universe. Information about the plasma universe can also be obtained by extrapolation of laboratory experiments and magnetospheric in situ measurements of plasmas. This approach is possible because it is likely that the basic properties of plasmas are the same everywhere. In order to test the usefulness of the plasma universe model it is applied to cosmogony. Such an approach seems to be rather successful. For example, the complicated structure of the Saturnian C ring can be accounted for. It is possible to reconstruct certain phenomena 4 to 5 billions of years ago with an accuracy of better than 1%.

  7. Dusty plasmas

    NASA Technical Reports Server (NTRS)

    Northrop, T. G.

    1992-01-01

    Dust grains immersed in plasma become charged. The charge is determined by the plasma characteristics, by secondary and photoemission from the grain, by grain velocity, and at any given instant by the past time history of the charging currents. This charge affects the Coulomb drag on a grain moving through the plasma. It affects the motion of the grain in an electromagnetic field of a planetary magnetosphere, and it is involved in the formation of the spokes in Saturn's rings and in the erosion of the rings by micrometeorites. And finally, it affects the coagulation rate of dust into larger bodies.

  8. Plasma Physics

    NSDL National Science Digital Library

    Rack, Philip D.

    This is a PDF version of lecture slides by Dr. Philip D. Rack (Assistant Professor, Department of Materials Science and Engineering at the University of Tennessee in Knoxville) that discuss information from the silicon's crystal structure to how to make doped semiconductors and the mechanics. Although the slides were written by Dr. Rack when he taught at the Rochester Institute of Technology, they are currently hosted by him at the University of Tennessee. Slide topics include plasma properties, DC glow discharge, ionization, plasma species, magnetrons, collisions, and chemical reactions. Numerous mathematical formulas are also presented.

  9. Plasma Shield

    NASA Astrophysics Data System (ADS)

    Hershcovitch, Ady

    2005-10-01

    The Plasma Shield is a vortex-stabilized arc that is employed to shield beams and workpiece area of interaction from atmospheric or liquid environment. A vortex-stabilized arc is established between a beam generating device (laser, ion or electron gun) and the target object. The arc, which is composed of a pure noble gas (chemically inert), engulfs the interaction region and generates an outward flow, thus, shielding it from any surrounding liquids (water) or atmospheric gases. The vortex is composed of a sacrificial gas or liquid that swirls around and stabilizes the arc. In current art, many industrial processes that involve ion and electron beams like, dry etching, micro-fabrication, machining, welding and melting are performed exclusively in vacuum, since guns, and accelerators must be kept at a reasonably high vacuum, and since chemical interactions with atmospheric gases adversely affect various processes. Various processes involving electron ion and laser beams can, with the Plasma Shield be performed in practically any environment (under water). It should allow for in situ repair of ship and nuclear reactor components, as well as in-air ion implantation of semiconductors. The plasma shield results in both thermal (since the plasma is hotter than the environment) and chemical shielding. The latter feature brings about in-vacuum process purity out of vacuum, and the thermal shielding aspect results in higher production rates. Experimental results will be presented. *Plasma Shield/Work supported by Acceleron, Inc., Connecticut Light & Power Co., US DOE funding under a NICE3 grant DE-FG41-01R110925, and Connecticut DEP.

  10. LCDProjektorenPlasmaLCDProjektorenPlasmaLCDProjektoren NEC MultiSync

    E-print Network

    Ott, Albrecht

    LCD·Projektoren·Plasma·LCD·Projektoren·Plasma·LCD·Projektoren NEC MultiSync® EA221WMe für CO² Wert Messung und Kontrolle· #12;LCD·Projektoren·Plasma·LCD·Projektoren·Plasma·LCD·Projektoren·Plasma·LCD·Projektoren·Plasma·LCD

  11. LCDProjektorenPlasmaLCDProjektorenPlasmaLCDProjektoren NEC MultiSync

    E-print Network

    Ott, Albrecht

    LCD·Projektoren·Plasma·LCD·Projektoren·Plasma·LCD·Projektoren NEC MultiSync® EA231WMi Voll (110 mm) mit 90°-Drehfunktion· #12;LCD·Projektoren·Plasma·LCD·Projektoren·Plasma·LCD·Projektoren·Plasma·LCD·Projektoren·Plasma·LCD

  12. Principles of Plasma Spectroscopy

    Microsoft Academic Search

    A. L. Osterheld

    1998-01-01

    This book gives a comprehensive treatment of plasma spectroscopy, the quantitative study of line and continuous radiation from high temperature plasmas. This highly interdisciplinary field combines elements of atomic, plasma and statistical physics, and has wide application to simulations and diagnostics of laboratory and astrophysical plasmas. Plasma spectroscopy is naturally intertwined with magnetic and inertial fusion energy science. Radiative processes

  13. Plasma Waves

    Microsoft Academic Search

    Alexander Piel

    \\u000a The interest in wave propagation in plasmas has different roots. One of these was the reflection of electromagnetic waves\\u000a by the ionosphere [91]. Stimulated by Guglielmo Marconi’s (1874–1937) experiments on long-distance radio in 1901, Oliver Heaviside\\u000a (1850–1925) [92] and, independently, Arthur Edwin Kennelly (1861–1939) [93] postulated, in 1902, that the Earth’s atmosphere\\u000a at high altitude must contain an electrically conducting

  14. Improved plasma accelerator

    NASA Technical Reports Server (NTRS)

    Cheng, D. Y.

    1971-01-01

    Converging, coaxial accelerator electrode configuration operates in vacuum as plasma gun. Plasma forms by periodic injections of high pressure gas that is ionized by electrical discharges. Deflagration mode of discharge provides acceleration, and converging contours of plasma gun provide focusing.

  15. Plasma Free Metanephrines

    MedlinePLUS

    ... of this website will be limited. Search Help? Plasma Free Metanephrines Share this page: Was this page helpful? Also known as: Plasma Metanephrines Formal name: Fractionated Plasma Free Metanephrines (Normetanephrine ...

  16. The Pervasive Plasma State

    NSDL National Science Digital Library

    Berk, Herbert L.

    This site by the Division of Plasma Physics of the American Physical Society explores plasma, a state of matter that blankets the Earth as a result of solar winds. Pictures and text are used to convey the significance and commonplace use of plasmas in society. Information provided by the site includes understanding plasmas, commercial applications, plasma in space, the future of plasma use, and more.

  17. Communication through plasma sheaths

    SciTech Connect

    Korotkevich, A. O.; Newell, A. C.; Zakharov, V. E. [Landau Institute for Theoretical Physics RAS, 2, Kosygin Str., Moscow, 119334 (Russian Federation); Department of Mathematics, University of Arizona, 617 N. Santa Rita Ave., Tucson, Arizona 85721 (United States); Department of Mathematics, University of Arizona, 617 N. Santa Rita Ave., Tucson, Arizona 85721 (United States); Lebedev Physical Institute RAS, 53, Leninsky Prosp., GSP-1 Moscow, 119991 (Russian Federation); Landau Institute for Theoretical Physics RAS, 2, Kosygin Str., Moscow, 119334 (Russian Federation) and Waves and Solitons LLC, 918 W. Windsong Dr., Phoenix, Arizona 85045 (United States)

    2007-10-15

    We wish to transmit messages to and from a hypersonic vehicle around which a plasma sheath has formed. For long distance transmission, the signal carrying these messages must be necessarily low frequency, typically 2 GHz, to which the plasma sheath is opaque. The idea is to use the plasma properties to make the plasma sheath appear transparent.

  18. Progress on plasma accelerators

    SciTech Connect

    Chen, P.

    1986-05-01

    Several plasma accelerator concepts are reviewed, with emphasis on the Plasma Beat Wave Accelerator (PBWA) and the Plasma Wake Field Accelerator (PWFA). Various accelerator physics issues regarding these schemes are discussed, and numerical examples on laboratory scale experiments are given. The efficiency of plasma accelerators is then revealed with suggestions on improvements. Sources that cause emittance growth are discussed briefly.

  19. Laser plasma diagnostics

    Microsoft Academic Search

    L. N. Piatnitskii

    1976-01-01

    This book discusses theoretical and experimental principles of laser techniques for plasma diagnostics. Special attention is given to interferometry and to methods based on light scattering by plasma electrons. The basic electromagnetic properties of a plasma are reviewed along with characteristics of plasma electromagnetic fluctuations and wave scattering. Fundamental principles of laser interferometry are outlined, the use of laser interferometry

  20. Principles of Plasma Diagnostics

    Microsoft Academic Search

    I. H. Hutchinson

    2002-01-01

    This book provides a systematic introduction to the physics of plasma diagnostics measurements. It develops from first principles the concepts needed to plan, execute and interpret plasma measurements, making it a suitable book for graduate students and professionals with little plasma physics background. The book will also be a valuable reference for seasoned plasma physicists, both experimental and theoretical, as

  1. Principles of Plasma Diagnostics

    Microsoft Academic Search

    I. H. Hutchinson

    2005-01-01

    This book provides a systematic introduction to the physics of plasma diagnostics measurements. It develops from first principles the concepts needed to plan, execute and interpret plasma measurements, making it a suitable book for graduate students and professionals with little plasma physics background. The book will also be a valuable reference for seasoned plasma physicists, both experimental and theoretical, as

  2. Plasmas for space propulsion

    NASA Astrophysics Data System (ADS)

    Ahedo, Eduardo

    2011-12-01

    Plasma thrusters are challenging the monopoly of chemical thrusters in space propulsion. The specific energy that can be deposited into a plasma beam is orders of magnitude larger than the specific chemical energy of known fuels. Plasma thrusters constitute a vast family of devices ranging from already commercial thrusters to incipient laboratory prototypes. Figures of merit in plasma propulsion are discussed. Plasma processes and conditions differ widely from one thruster to another, with the pre-eminence of magnetized, weakly collisional plasmas. Energy is imparted to the plasma via either energetic electron injection, biased electrodes or electromagnetic irradiation. Plasma acceleration can be electrothermal, electrostatic or electromagnetic. Plasma-wall interaction affects energy deposition and erosion of thruster elements, and thus is central for thruster efficiency and lifetime. Magnetic confinement and magnetic nozzles are present in several devices. Oscillations and turbulent transport are intrinsic to the performances of some thrusters. Several thrusters are selected in order to discuss these relevant plasma phenomena.

  3. Plasma Physics PART Al: INTRODUCTION TO PLASMA SCIENCE

    E-print Network

    Chen, Francis F.

    Plasma Physics PART Al: INTRODUCTION TO PLASMA SCIENCE I. What is a plasma? 1 II. Plasma fundamentals 3 1. Quasineutrality and Debye length 2. Plasma frequency and acoustic velocity 3. Larmor radius; magnetic buckets Cross section data 21 PART A3: PLASMA SOURCES I IV. Introduction to plasma sources 25 1

  4. Plasma-maser effects in dusty plasma

    Microsoft Academic Search

    Xuyu Wang; Zhongyuan Li

    1996-01-01

    The plasma-maser instability of Langmuir wave in multicomponent plasma with stationary charged particles is considered. The up-conversion of the wave energy from low-frequency waves to the high-frequency wave is much enhanced owing to the deeper energy exchange between resonant waves and particles in dusty plasma. This results should be useful to interpret the anomalous high-frequency radiation phenomena in laboratory and

  5. Neutrino plasma coupling in dense astrophysical plasmas

    NASA Astrophysics Data System (ADS)

    Bingham, R.; Silva, L. O.; Mendonça, J. T.; Shukla, P. K.; Mori, W. B.; Serbeto, A.

    2004-12-01

    There is considerable interest in the propagation dynamics of intense neutrino beams in a background dispersive medium such as dense plasmas, particularly in the search for a mechanism to explain the dynamics of type II supernovae. Neutrino interactions with matter are usually considered as single particle interactions. All the single particle mechanisms describing the dynamical properties of neutrinos in matter are analogous with the processes involving single electron interactions with a medium such as Compton scattering, Cerenkov radiation, etc. However, it is well known that beams of electrons moving through a plasma give rise to a new class of processes known as collective interactions, such as two stream instabilities, which result in either the absorption or generation of plasma waves. Employing the relativistic kinetic equations for neutrinos interacting with dense plasmas via the weak force, we explore collective plasma streaming instabilities driven by neutrino beams. We examine the anomalous transfer between neutrinos and dense plasma via excitation of electron plasma waves. The nonlinear coupling between an intense neutrino beam and a plasma reveals the presence of two regimes, a hydrodynamic regime and a kinetic regime. The latter is responsible for Landau damping or growth of electron plasma waves. In dense fusion stellar plasmas neutrino Landau damping can play a significant role as an additional stellar plasma cooling process. Another interesting result is an asymmetry in the momentum balance imported by the neutrinos to the core of the exploding star due to symmetry breaking by the collapsed star's magnetic fields. This results in a directed velocity of the resulting neutron star or pulsar, explaining the so called 'birth' velocity.

  6. LCDProjektorenPlasmaLCDProjektorenPlasmaLCDProjektoren NEC MultiSync

    E-print Network

    Ott, Albrecht

    LCD·Projektoren·Plasma·LCD·Projektoren·Plasma·LCD·Projektoren NEC MultiSync® EA241WM Voll dem Eco-Modus und dem besonderen Maßstab für CO2- Ausstoß · #12;LCD·Projektoren·Plasma·LCD·Projektoren·Plasma·LCD·Projektoren·Plasma·LCD·Projektoren·Plasma·LCD

  7. LCDProjektorenPlasmaLCDProjektorenPlasmaLCDProjektoren NEC MultiSync

    E-print Network

    Ott, Albrecht

    LCD·Projektoren·Plasma·LCD·Projektoren·Plasma·LCD·Projektoren NEC MultiSync® E222W EntryViKey· Niedriger Energieverbrauch dank Eco Mode und einzigartiger, integrierter CO2 Einspar- Anzeige · #12;LCD·Projektoren·Plasma·LCD·Projektoren·Plasma·LCD·Projektoren·Plasma·LCD·Projektoren·Plasma·LCD NEC MultiSync® E

  8. LCDProjektorenPlasmaLCDProjektorenPlasmaLCDProjektoren NEC MultiSync

    E-print Network

    Ott, Albrecht

    LCD·Projektoren·Plasma·LCD·Projektoren·Plasma·LCD·Projektoren NEC MultiSync® LCD2690WUXi² Hochinnovativer LCD-Monitor im Wide Format mit herausragenden ergonomischen und wirtschaftlichen Eigenschaften Funktionen wie CableComp, ColorComp bzw. X-light® Pro· #12;LCD·Projektoren·Plasma·LCD·Projektoren·Plasma·LCD·Projektoren·Plasma·LCD·Projektoren·Plasma·LCD

  9. Plasma amino acids

    MedlinePLUS

    Plasma amino acids is a screening test done on infants that looks at the amounts of amino ... Laboratory error High or low amounts of individual plasma amino acids must be considered with other information. ...

  10. Steam plasma arc cutting

    SciTech Connect

    Pauser, H.; Laimer, J.; Stori, H.

    1999-07-01

    Plasma arc cutting is a widely used method for cutting metals. The availability of small portable units using compressed air as plasma gas makes these devices suitable for the use in job shops. However, the need for compressed air means less flexibility in field applications. Possible solution strategies to overcome this disadvantage are the integration of the air supply on board or the production of plasma gas in situ. A plasma cutting device using the later concept will be presented.

  11. Plasma photonic crystal

    Microsoft Academic Search

    Wei Li; Yong Zhao; Ruizhen Cui; Haitao Zhang

    2009-01-01

    Plasma photonic crystals are presented in this paper. A plasma photonic crystal can control the propagation of electromagnetic\\u000a waves. Similar to other photonic crystals, the permittivity of a plasma photonic crystal is distributed as periodic arrays.\\u000a The properties of periodic arrays of plasma can broaden the range of frequency and enhance the efficiency of beam-wave interaction.\\u000a In special uses, the

  12. Coalition for Plasma Science

    NSDL National Science Digital Library

    Created to increase public understanding of plasma science, this site presents brief papers introducing particular aspects of plasma science and its practical applications, plus an excellent Teachers Guide to Plasma Science Resources (see "Educational Materials"), designed by teachers for teachers and students. The Guide provides annotated links to the best of online plasma-education materials, including classroom-tested materials and K-12 teaching aids. Most of the listings are accompanied by a checklist of the National Science Standards the resource fulfills.

  13. Waves in Dusty Plasmas

    Microsoft Academic Search

    M. Rosenberg

    2005-01-01

    Summary form only given. Dusty plasmas are ionized gases containing massive charged dust grains. The presence of charged dust in a plasma can affect the behavior of waves and instabilities and also the interaction of electromagnetic (EM) waves with the plasma. We discuss some recent theoretical work in these areas. Instabilities may play important roles in various applications in both

  14. Electrodynamics of nonequilibrium plasma

    Microsoft Academic Search

    A. G. Sitenko; H. Wilhelmsson

    1973-01-01

    Plasma physics is experiencing a period of intensive development and is at present a most of vital part of modern physics. In the field of electrodynamics of plasmas the theory of fluctuations is of great interest. The fluctuations in a plasma are usually described by their spectral functions. The fluctuation spectrum is a quantity directly observable in a scattering experiment.

  15. Plasma Treatment of Polymers

    Microsoft Academic Search

    Jeremy M. Grace; Louis J. Gerenser

    2003-01-01

    Plasma treatment of polymers encompasses a variety of plasma technologies and polymeric materials for a wide range of applications and dates back to at least the 1960s. In this article we provide a brief review of the United States patent literature on plasma surface modification technologies and a brief review of the scientific literature on investigations of the effects of

  16. Perspectives on Plasma

    NSDL National Science Digital Library

    Eastman, Timothy E.

    Originally conceived and launched by consultant and Senior Research Associate Dr. Timothy E. Eastman at the Space Science Institute in Boulder, Colorado, the Perspectives on Plasma Web site represents all aspects of plasma science and technology. Visitors can explore the basics of plasma, its applications, view a photo gallery, and much more.

  17. Antimatter plasmas and antihydrogen

    Microsoft Academic Search

    R. G. Greaves; C. M. Surko

    1997-01-01

    Recent successes in confining antimatter in the form of positron and antiproton plasmas have created new scientific and technological opportunities. Plasma techniques have been the cornerstone of experimental work in this area, and this is likely to be true for the foreseeable future. Work by a number of groups on trapping antimatter plasmas is summarized, and an overview of the

  18. Plasma & RF Fundamentals

    NSDL National Science Digital Library

    This is a description for a learning module from Maricopa Advanced Technology Education Center. This PDF describes the module; access may be purchased by visiting the MATEC website. One third of modern semiconductor process steps and a variety of other applications employ plasma technology. RF energy is commonly used to generate and maintain a plasma which accelerates chemical processes or provides other desired outcomes such as light emission. This module is the first in a series that builds a knowledge foundation for understanding plasma technology and RF energy. Concepts and principles covered include particle behavior under plasma conditions, changes in electromagnetic wave forms, and related variables that affect RF/plasma applications.

  19. Industrial Plasma Antennas

    NASA Astrophysics Data System (ADS)

    Alexeff, Igor

    2007-11-01

    This presentation summarizes an extensive program on plasma antennas. Plasma antennas are just as effective as metal antennas. In addition, they can transmit, receive and reflect lower frequency signals while being transparent to higher frequency signals. When de-energized, they electrically disappear. Plasma noise does not appear to be a problem. New technology that has been developed include a method of operating at high plasma density at minimal power consumption, a novel technique of noise reduction, and a method of opening a plasma window in a plasma microwave barrier on a time scale of microseconds rather than the usual time scale of milliseconds due to plasma decay. We are at present testing an intelligent plasma antenna in which a plasma ``window'' in a circular plasma barrier surrounding an antenna rotates azimuthally, seeking a radio transmitter. When located, a computer locks onto the transmitter. When the transmitter is de-energized, the plasma window recommences scanning. Commercial interest is strong, with invited papers being presented for 4 years in succession at the SMi Stealth Conference in London, UK, an operating model on permanent exhibition at the Booze-Allen headquarters in Alexandria, VA, and strong interest from Lockheed-Martin. In collaboration with Ted Anderson, Haleakala R&D Corp.; Esmaeil Farshi, Fred Dyer, Jeffrey Peck, Eric Pradeep, Nanditha Pulasani, and Naresh Karnam, University of Tennessee.

  20. Laminar Plasma Dynamos

    E-print Network

    Zhehui Wang; Vladimir I. Pariev; Cris W. Barnes; Daniel C. Barnes

    2002-03-07

    A new kind of dynamo utilizing flowing laboratory plasmas has been identified. Conversion of plasma kinetic energy to magnetic energy is verified numerically by kinematic dynamo simulations for magnetic Reynolds numbers above 210. As opposed to intrinsically-turbulent liquid-sodium dynamos, the proposed plasma dynamos correspond to laminar flow topology. Modest plasma parameters, 1-20 eV temperatures, 10^{19}-10^{20} m^{-3} densities in 0.3-1.0 m scale-lengths driven by velocities on the order of the Alfven Critical Ionization Velocity (CIV), self-consistently satisfy the conditions needed for the magnetic field amplication. Growth rates for the plasma dynamos are obtained numerically with different geometry and magnetic Reynolds numbers. Magnetic-field-free coaxial plasma guns can be used to sustain the plasma flow and the dynamo.

  1. Laminar Plasma Dynamos

    E-print Network

    Wang, Z; Barnes, C W; Barnes, D C; Wang, Zhehui; Pariev, Vladimir I.; Barnes, Cris W.; Barnes, Daniel C.

    2002-01-01

    A new kind of dynamo utilizing flowing laboratory plasmas has been identified. Conversion of plasma kinetic energy to magnetic energy is verified numerically by kinematic dynamo simulations for magnetic Reynolds numbers above 210. As opposed to intrinsically-turbulent liquid-sodium dynamos, the proposed plasma dynamos correspond to laminar flow topology. Modest plasma parameters, 1-20 eV temperatures, 10^{19}-10^{20} m^{-3} densities in 0.3-1.0 m scale-lengths driven by velocities on the order of the Alfven Critical Ionization Velocity (CIV), self-consistently satisfy the conditions needed for the magnetic field amplication. Growth rates for the plasma dynamos are obtained numerically with different geometry and magnetic Reynolds numbers. Magnetic-field-free coaxial plasma guns can be used to sustain the plasma flow and the dynamo.

  2. Dispersion and thermal effects on electromagnetic instabilities in the precursor of relativistic shocks

    Microsoft Academic Search

    Martin Lemoine; Guy Pelletier

    2011-01-01

    Fermi acceleration can develop efficiently at relativistic collisionless shock waves provided the upstream (unshocked) plasma is weakly magnetized. This has been both indicated by analytical theory and observed in numerical particle-in-cell simulations. At low magnetization, the large size of the shock precursor indeed provides enough time for electromagnetic micro-instabilities to grow, and such micro-instabilities generate small-scale turbulence that in turn

  3. Plasma-maser instability in dusty plasmas

    Microsoft Academic Search

    Mitsuhiro Nambu; Padma K. Shukla; Sergey V. Vladimirov

    1993-01-01

    The growth rates of the Langmuir and electromagnetic radiation due to the plasma-maser instability in multicomponent unmagnetized plasmas with stationary charged particulates are obtained. The up-conversion of the wave energy from ion-acoustic oscillations to the test Langmuir and electromagnetic waves is much enhanced owing to the enhanced accelaration of electrons by the dust ion-acoustic mode. The results could be important

  4. Plasma Biomedicine in Orthopedics

    NASA Astrophysics Data System (ADS)

    Hamaguchi, Satsohi

    2012-10-01

    Various effects of plasmas irradiation on cells, tissues, and biomaterials relevant for orthopedic applications have been examined. For direct application of plasmas to living cells or tissues, dielectric barrier discharges (DBDs) with helium flows into ambient air were used. For biomaterial processing, on the other hand, either helium DBDs mentioned above or low-pressure discharges generated in a chamber were used. In this presentation, plasma effects on cell proliferation and plasma treatment for artificial bones will be discussed. First, the conditions for enhanced cell proliferation in vitro by plasma applications have been examined. The discharge conditions for cell proliferation depend sensitively on cell types. Since cell proliferation can be enhanced even when the cells are cultured in a plasma pre-treated medium, long-life reactive species generated in the medium by plasma application or large molecules (such as proteins) in the medium modified by the plasma are likely to be the cause of cell proliferation. It has been found that there is strong correlation between (organic) hydroperoxide generation and cell proliferation. Second, effects of plasma-treated artificial bones made of porous hydroxyapatite (HA) have been examined in vitro and vivo. It has been found that plasma treatment increases hydrophilicity of the surfaces of microscopic inner pores, which directly or indirectly promotes differentiation of mesenchymal stem cells introduced into the pores and therefore causes faster bone growth. The work has been performed in collaboration with Prof. H. Yoshikawa and his group members at the School of Medicine, Osaka University.

  5. Inductive plasma sources for plasma implantation and deposition

    Microsoft Academic Search

    Michel Tuszewski; Ivars Henins; Michael Nastasi; W. Kent Scarborough; Kevin C. Walter; Doug H. Lee

    1998-01-01

    External and reentrant radio frequency inductive plasma sources are developed for plasma ion implantation and deposition processes in a 1.8 m3 vacuum vessel. Plasma densities in the range 1016 -1017 m-3 desirable for the above processes. External plasma sources could not yield the required plasma densities because of high particle losses in the transition region between the source and the

  6. Plasma Sheath Modeling Using The Three Fluid Plasma Model

    Microsoft Academic Search

    Robert Lilly; Uri Shumlak

    2010-01-01

    There has been renewed interest in the use of plasma actuators for high speed flow control applications. In the plasma actuator, current is driven through the surrounding weakly ionized plasma to impart control moments on the hypersonic vehicle. Accurate modeling of plasma sheath physics is of particular importance for the plasmas found in high speed flight applications. This study employs

  7. Plasma atomic layer etching using conventional plasma equipment Ankur Agarwala

    E-print Network

    Kushner, Mark

    Plasma atomic layer etching using conventional plasma equipment Ankur Agarwala Department plasma etching processes having atomic layer resolution. The basis of plasma atomic layer etching PALE will be discussed with the goal of demonstrating the potential of using conventional plasma etching equipment having

  8. Plasma-Therm Workshop: Fundamentals of Plasma Processing (Etching & Deposition)

    E-print Network

    Martin, Jan M.L.

    Plasma-Therm Workshop: Fundamentals of Plasma Processing (Etching & Deposition) Nanofabrication The workshop will focus on the fundamentals of plasma etching and deposition. Lectures will include an introduction to vacuum technology, the basics of plasma and plasma reactors and an overview of mechanisms

  9. Plasma abatement of perfluorocompounds in inductively coupled plasma reactors

    E-print Network

    Kushner, Mark

    Plasma abatement of perfluorocompounds in inductively coupled plasma reactors Xudong ``Peter'' Xu PFCs , gases which have large global warming potentials, are widely used in plasma processing, the effluents from plasma tools using these gases typically have large mole fractions of PFCs. The use of plasma

  10. Modeling of plasma behavior in a plasma electrode Pockels cell

    Microsoft Academic Search

    Charles D. Boley; Mark A. Rhodes

    1999-01-01

    We present three interrelated models of plasma behavior in a plasma electrode Pockels cell (PEPC). In a PEPC, plasma discharges are formed on both sides of a thin, large-aperture electro-optic crystal (typically KDP). The plasmas act as optically transparent, highly conductive electrodes, allowing uniform application of a longitudinal field to induce birefringence in the crystal. First, we model the plasma

  11. Advanced plasma diagnostics for plasma processing

    NASA Astrophysics Data System (ADS)

    Malyshev, Mikhail Victorovich

    1999-10-01

    A new, non-intrusive, non-perturbing diagnostic method was developed that can be broadly applied to low pressure, weakly ionized plasmas and glow discharges-trace rare gases optical emission spectroscopy (TRG-OES). The method is based on a comparison of intensities of atomic emission from trace amounts of inert gases (He, Ne, Ar, Kr, and Xe) that are added to the discharge to intensities calculated from the theoretical model. The model assumes a Maxwellian electron energy distribution function (EEDF), computes the population of emitting levels both from the ground state and the metastable states of rare gases, and from the best fit between theory and experiment determines electron temperature (Te). Subject to conditions, TRG-OES can also yield electron density or its upper or lower limit. From the comparison of the emission from levels excited predominantly by high energy electrons to that excited by low energy electrons, information about the EEDF can be obtained. The use of TRG-OES also allows a traditionally qualitative actinometry technique (determination of concentration of radical species in plasma through optical emission) to become a precise quantitative method by including Te and rare gases metastables effects. A combination of TRG-OES, advanced actinometry, and Langmuir probe measurements was applied to several different plasma reactors and regimes of operation. Te measurements and experiments to correct excitation cross section were conducted in a laboratory helical resonator. Two chamber configuration of a commercial (Lam Research) metal etcher were studied to determine the effects of plasma parameters on plasma-induced damage. Two different methods (RF inductive coupling and ultra-high frequency coupling) for generating a plasma in a prototype reactor were also studied. Pulsed plasmas, a potential candidate to eliminate the plasma-induced damage to microelectronics devices that occurs in manufacturing due to differential charging of the wafer, have been studied in a laboratory inductively- coupled reactor. Time dependencies of Te,ne,n+ i,n- i and the transition of the plasma from its electron-ion to ion-ion state (the ion- ion state promises to eliminate the plasma-induced damage) were investigated with a combination of the Langmuir probe, microwave interferometry, and TRG-OES.

  12. Helicons in Unbounded Plasmas.

    PubMed

    Stenzel, R L; Urrutia, J M

    2015-05-22

    Helicons are whistler modes with helical phase fronts. They have been studied in solid state plasmas and in discharge tubes where boundaries and nonuniformities are ever present. The present work shows that helicons also exist in unbounded and uniform plasmas, thereby bridging the fields of laboratory and space plasma physics. First measurements of helicon field lines in three dimensional space are presented. Helicons with negative and positive mode numbers can propagate with equal amplitudes. PMID:26047237

  13. Cassini Plasma Spectrometer Investigation

    Microsoft Academic Search

    D. T. Young; J. J. Berthelier; M. Blanc; J. L. Burch; A. J. Coates; R. Goldstein; M. Grande; T. W. Hill; R. E. Johnson; V. Kelha; D. J. Mccomas; E. C. Sittler; K. R. Svenes; K. Szegö; P. Tanskanen; K. Ahola; D. Anderson; S. Bakshi; R. A. Baragiola; B. L. Barraclough; R. K. Black; S. Bolton; T. Booker; R. Bowman; P. Casey; F. J. Crary; D. Delapp; G. Dirks; N. Eaker; H. Funsten; J. D. Furman; J. T. Gosling; H. Hannula; C. Holmlund; H. Huomo; J. M. Illiano; P. Jensen; M. A. Johnson; D. R. Linder; T. Luntama; S. Maurice; K. P. Mccabe; K. Mursula; B. T. Narheim; J. E. Nordholt; A. Preece; J. Rudzki; A. Ruitberg; K. Smith; S. Szalai; M. F. Thomsen; K. Viherkanto; J. Vilppola; T. Vollmer; T. E. Wahl; M. Wüest; T. Ylikorpi; C. Zinsmeyer

    2004-01-01

    The Cassini Plasma Spectrometer (CAPS) will make comprehensive three-dimensional mass-resolved measurements of the full variety of plasma phenomena found in Saturn’s magnetosphere. Our fundamental scientific goals are to understand the nature of saturnian plasmas primarily their sources of ionization, and the means by which they are accelerated, transported, and lost. In so doing the CAPS investigation will contribute to understanding

  14. Plasma relativistic microwave electronics

    Microsoft Academic Search

    M. V. Kuzelev; O. T. Loza; A. A. Rukhadze; P. S. Strelkov; A. G. Shkvarunets

    2001-01-01

    The principles of plasma relativistic microwave electronics based on the stimulated Cherenkov emission of electromagnetic\\u000a waves during the interaction of a relativistic electron beam with a plasma are formulated. A theory of relativistic Cherenkov\\u000a plasma microwave oscillators and amplifiers is developed, and model experimental devices are elaborated and investigated.\\u000a The emission mechanisms are studied theoretically. The efficiencies and frequency spectra

  15. Plasma Membrane ATPases

    Microsoft Academic Search

    Michael G. Palmgren; Lone Bækgaard; Rosa López-Marqués; Anja Fuglsang

    \\u000a The plasma membrane separates the cellular contents from the surrounding environment. Nutrients must enter through the plasma\\u000a membrane in order to reach the cell interior, and toxic metabolites and several ions leave the cell by traveling across the\\u000a same barrier. Biological pumps in the plasma membrane include ABC transporters, vacuolar (V-type) H+ pumps, and P-type pumps. These pumps all utilize

  16. Plasma Membrane Protein Trafficking

    Microsoft Academic Search

    Wendy Ann Peer

    \\u000a The plasma membrane is the interface between the cytosol and the external environment. The proteins that reside and function\\u000a on the plasma membrane regulate the cellular entrance and exit of bioactive molecules, actuate signaling cascades in response\\u000a to external stimuli, and potentiate interactions between cells. The presence and abundance of proteins on the plasma membrane\\u000a is regulated by anterograde and

  17. Helicons in Unbounded Plasmas

    NASA Astrophysics Data System (ADS)

    Stenzel, R. L.; Urrutia, J. M.

    2015-05-01

    Helicons are whistler modes with helical phase fronts. They have been studied in solid state plasmas and in discharge tubes where boundaries and nonuniformities are ever present. The present work shows that helicons also exist in unbounded and uniform plasmas, thereby bridging the fields of laboratory and space plasma physics. First measurements of helicon field lines in three dimensional space are presented. Helicons with negative and positive mode numbers can propagate with equal amplitudes.

  18. Plasma physics in Latin America

    Microsoft Academic Search

    Adolfo B. Rodrigo

    1995-01-01

    The status of plasma physics in Latin America is reviewed. The review surveys the history and present situation of the regional activities in high-temperature plasma research, plasma astrophysics, and technological applications of plasma physics. In particular, it presents data on the trends of evolution of scientific staff, annual operating budget, and publication rate for the major Latin American plasma groups

  19. Plasma cleaning for waste minimization

    Microsoft Academic Search

    1993-01-01

    Although plasma cleaning is a recognized substitute for solvent cleaning in removing organic contaminants, some universal problems in plasma cleaning processes prevent wider use of plasma techniques. Lack of understanding of the fundamental mechanisms of the process, unreliable endpoint detection techniques, and slow process times make plasma cleaning processes less than desirable. Our approach to address these plasma cleaning problems

  20. Experimental plasma relativistic microwave electronics

    Microsoft Academic Search

    Oleg T. Loza; Anatoly G. Shkvarunets; Pavel S. Strelkov

    1998-01-01

    The presence of plasma affects drastically the operation of microwave devices driven by high-current relativistic electron beams. Loading vacuum microwave oscillators with plasma changes the power and frequency band of the radiation. The Cherenkov plasma maser, that operates only with plasma inside, has both promising advantages and inherent disadvantages comparatively to the vacuum devices. Besides, plasma appears in a relativistic

  1. PLASMA PHYSICS PPPL UC Davis

    E-print Network

    PRINCETON PLASMA PHYSICS LABORATORY PPPL UC Davis PRINCETON PLASMA PHYSICS LABORATORY PPPL UC Davis. Domier and N.C. Luhmann, Jr. UC at Davis at Workshop on Long Time Simulations of Kinetic Plasmas April 21, 2006 Hyatt Regency, Dallas, TX #12;PRINCETON PLASMA PHYSICS LABORATORY PPPL UC Davis PRINCETON PLASMA

  2. Plasma waves at Venus

    NASA Astrophysics Data System (ADS)

    Strangeway, R. J.

    1991-02-01

    Many significant wave phenomena have been discovered at Venus with the plasma wave instrument on the Pioneer Venus Orbiter. It has been shown that whistler-mode waves in the magnetosheath of the planet may be an important source of energy for the topside ionosphere. Plasma waves are also associated with thickening of the ionopause current layer. Current-generated waves in plasma clouds may also provide anomalous resistance resulting in electron acceleration, possibly producing aurora. Ion-acoustic waves are observed in the bow shock, and appear to be a feature of the magnetotail boundary. Lastly, plasma waves have been cited as evidence for lightning on Venus.

  3. [Therapeutic plasmas available worldwide].

    PubMed

    Martinaud, C; Cauet, A; Sailliol, A

    2013-05-01

    Therapeutic plasma is a current product; French guidelines were reviewed in 2012. Connections between more or less closed countries are frequent, during relief disasters as well as in war settings. This is associated with the increasing use of plasma in the management of casualties. Additionally, The real possibility of lack of plasma supply in some countries provides a fundamental interest of the knowledge of foreign blood supply organizations. We present here the main divergences and mutual point between plasmas available worldwide. We present the main characteristics of each product. PMID:23522688

  4. Leo space plasma interactions

    NASA Technical Reports Server (NTRS)

    Ferguson, Dale C.

    1991-01-01

    Photovoltaic arrays interact with the low earth orbit (LEO) space plasma in two fundamentally different ways. One way is the steady collection of current from the plasma onto exposed conductors and semiconductors. The relative currents collected by different parts of the array will then determine the floating potential of the spacecraft. In addition, these steady state collected currents may lead to sputtering or heating of the array by the ions or electrons collected, respectively. The second kind of interaction is the short time scale arc into the space plasma, which may deplete the array and/or spacecraft of stored charge, damage solar cells, and produce EMI. Such arcs only occur at high negative potentials relative to the space plasma potential, and depend on the steady state ion currents being collected. New high voltage solar arrays being incorporated into advanced spacecraft and space platforms may be endangered by these plasma interactions. Recent advances in laboratory testing and current collection modeling promise the capability of controlling, and perhaps even using, these space plasma interactions to enable design of reliable high voltage space power systems. Some of the new results may have an impact on solar cell spacing and/or coverslide design. Planned space flight experiments are necessary to confirm the models of high voltage solar array plasma interactions. Finally, computerized, integrated plasma interactions design tools are being constructed to place plasma interactions models into the hands of the spacecraft designer.

  5. Pilot Plasma Engine

    NASA Technical Reports Server (NTRS)

    1961-01-01

    The Pilot Plasma Engine. This traveling wave accelerator, being operated by Raymond W. Plamer of the Lewis Electromagnetic Propulsion Division, uses an alternating current power supply. The AC feature avoids the life limitations of direct current accelerators where electrode parts rapidly deteriorate from touching the plasma. The traveling wave accelerator works like its name. A neutral plasma of electrons and ions is produced in the source at the left. This plasma moves to the right and is accelerated by a moving magnetic field in the four black coils. Such acceleration produces thrust, perhaps enough to propel a future spacecraft beyond the Moon.

  6. EDITORIAL: Plasma jets and plasma bullets Plasma jets and plasma bullets

    NASA Astrophysics Data System (ADS)

    Kong, M. G.; Ganguly, B. N.; Hicks, R. F.

    2012-06-01

    Plasma plumes, or plasma jets, belong to a large family of gas discharges whereby the discharge plasma is extended beyond the plasma generation region into the surrounding ambience, either by a field (e.g. electromagnetic, convective gas flow, or shock wave) or a gradient of a directionless physical quantity (e.g. particle density, pressure, or temperature). This physical extension of a plasma plume gives rise to a strong interaction with its surrounding environment, and the interaction alters the properties of both the plasma and the environment, often in a nonlinear and dynamic fashion. The plasma is therefore not confined by defined physical walls, thus extending opportunities for material treatment applications as well as bringing in new challenges in science and technology associated with complex open-boundary problems. Some of the most common examples may be found in dense plasmas with very high dissipation of externally supplied energy (e.g. in electrical, optical or thermal forms) and often in or close to thermal equilibrium. For these dense plasmas, their characteristics are determined predominantly by strong physical forces of different fields, such as electrical, magnetic, thermal, shock wave, and their nonlinear interactions [1]. Common to these dense plasma plumes are significant macroscopic plasma movement and considerable decomposition of solid materials (e.g. vaporization). Their applications are numerous and include detection of elemental traces, synthesis of high-temperature materials and welding, laser--plasma interactions, and relativistic jets in particle accelerators and in space [2]-[4]. Scientific challenges in the understanding of plasma jets are exciting and multidisciplinary, involving interweaving transitions of all four states of matter, and their technological applications are wide-ranging and growing rapidly. Using the Web of Science database, a search for journal papers on non-fusion plasma jets reveals that a long initial phase up to 1990 with only 31 papers per year on average, and a total of some 1300 papers, precedes a considerable growth of some 35-50% in research activity every five years, over the last 20 years or so. As shown in the table, the annual dissemination of the field is more than 1600 papers and the total number of papers is in excess of 20000. This upwards trajectory is typical of a strong and growing subject area in physical science, with considerable capacity in both fundamental science and applications. PeriodNumber of papersPapers per annum 1948-1990130031 1991-19952279456 1996-20003447689 2001-20054571914 2006-201066401328 2011 1658 In many of the dense plasma jets discussed above, strong physical forces generated by the plasma are often desired and this favours plasma generation at elevated gas pressure, including atmospheric pressure, which favours a high level of gas ionization. Historically it has been challenging to reduce and control the strong physical forces in high-pressure plasmas for applications where these are unwanted, for example, surface modification of polymeric sheets [5]. Indeed, there is a real need for a vast range of material processing applications at temperatures below 100oC (or below 400 K) and this favours atmospheric-pressure plasma jets sustained far from thermal equilibrium with the dissipated electrical energy largely used not in heat generation but in unleashing non-equilibrium chemical reactions. The long-standing difficulty of effectively controlling the level of gas ionization at atmospheric pressure was overcome by the technological breakthrough of achieving atmospheric-pressure glow discharges in the late 1980s [6]. A related challenge stemming from high collisionality of atmospheric-pressure plasmas (v >> ?0) means that large-area plasmas sustained between parallel-plate electrodes are very susceptible to strong plasma instabilities when molecular gases are introduced for processing applications. This led to an effective technological solution in the early to late 1990s of confining atmospheric plasmas in a small volume

  7. LCDProjektorenPlasmaLCDProjektorenPlasmaLCDProjektoren NEC MultiSync

    E-print Network

    Ott, Albrecht

    LCD·Projektoren·Plasma·LCD·Projektoren·Plasma·LCD·Projektoren NEC MultiSync® EA190M Professionelle Office-LCD-Monitore mit herausragender Display-Qualität und ergonomischen, ökologischen Details. 19" (5TM· Vielseitige und leichte Montage (VESA-Normung) mit NaViSet und NaViKey· #12;LCD·Projektoren·Plasma·LCD·Projektoren·Plasma·LCD·Projektoren·Plasma·LCD·Projektoren·Plasma·LCD

  8. Measuring the plasma density of a ferroelectric plasma source in an expanding plasma

    E-print Network

    Measuring the plasma density of a ferroelectric plasma source in an expanding plasma A. Dunaevsky and N. J. Fisch Princeton Plasma Physics Laboratory, Princeton University, P.O. Box 451, Princeton, New temperature at the surface of a ferroelectric plasma source were deduced from floating probe measurements

  9. Partially ionized plasmas, including the Third Symposium on Uranium Plasmas

    NASA Technical Reports Server (NTRS)

    Krishnan, M.

    1976-01-01

    Fundamentals of both electrically and fission generated plasmas are discussed. Research in gaseous fuel reactors using uranium hexafluoride is described and other partially ionized plasma applications are discussed.

  10. Separative power of plasma centrifuges

    NASA Astrophysics Data System (ADS)

    Simpson, S. W.

    1981-10-01

    A three-fluid model of rotating plasmas is used to predict the efficiency of plasma centrifuges. It is found that partially ionized plasma centrifuges of the type investigated cannot match the separative power of gas centrifuges for uranium enrichment.

  11. Diagnostics for plasma processing (etching plasmas) (invited)

    SciTech Connect

    Hershkowitz, N.; Breun, R.A. [Engineering Research Center for Plasma Aided Manufacturing, University of Wisconsin--Madison, Madison, Wisconsin 53706 (United States)] [Engineering Research Center for Plasma Aided Manufacturing, University of Wisconsin--Madison, Madison, Wisconsin 53706 (United States)

    1997-01-01

    Plasma processing diagnostics play two different roles{emdash}characterization and control. The goal of plasma characterization is to establish connections of data with external parameters and to verify models. The goal of control diagnostics is to make noninvasive {ital in situ} measurements of relevant processing parameters. Diagnostics used in semiconductor etching are considered. These include Langmuir probes, laser induced fluorescence, optical emission spectroscopy, infrared and Fourier transform infrared absorption spectroscopy, mass spectrometry, microwave interferometry, and radio frequency diagnostics. An example is given of the use of many diagnostics in characterizing SiO{sub 2} and Si etching by fluorocarbons. {copyright} {ital 1997 American Institute of Physics.}

  12. Plasma Cell Disorders

    MedlinePLUS

    ... cell disorders are uncommon. They begin when a single plasma cell multiplies excessively. The resulting group of genetically identical ... a clone) produces a large quantity of a single type of antibody (immunoglobulin). Plasma cells develop from B cells (B lymphocytes), a type ...

  13. Plasma microwave electronics

    Microsoft Academic Search

    L. S. Bogdankevich; M. V. Kuzelev; Anri A. Rukhadze

    1981-01-01

    The theory of Cherenkov and cyclotron plasma sources of coherent microwave radiation excited by intense electron beams is reviewed systematically. The linear approximation of the theory yields the output frequency spectra, the wave growth rates, and the threshold electron beam currents required for exciting these sources. The general theory is illustrated for some particular devices: the forward-wave plasma Cherenkov source,

  14. Atoms in dense plasmas

    SciTech Connect

    More, R.M.

    1986-01-01

    Recent experiments with high-power pulsed lasers have strongly encouraged the development of improved theoretical understanding of highly charged ions in a dense plasma environment. This work examines the theory of dense plasmas with emphasis on general rules which govern matter at extreme high temperature and density. 106 refs., 23 figs.

  15. Triggered plasma opening switch

    DOEpatents

    Mendel, Clifford W. (Albuquerque, NM)

    1988-01-01

    A triggerable opening switch for a very high voltage and current pulse includes a transmission line extending from a source to a load and having an intermediate switch section including a plasma for conducting electrons between transmission line conductors and a magnetic field for breaking the plasma conduction path and magnetically insulating the electrons when it is desired to open the switch.

  16. Diagnostics of CVL plasma

    NASA Astrophysics Data System (ADS)

    Petrash, Gueorgii G.

    1995-08-01

    A review of the measurements of plasma parameters (gas temperature, density, and temperature of electrons) in active media of pulsed copper vapor lasers is given. Essential disagreement exists between many published results. The possible reasons of this disagreement and experimental difficulties associated with the measurements are discussed. Some suggestions for future CVL plasma diagnostics measurements are given.

  17. Plasma technology directory

    SciTech Connect

    Ward, P.P.; Dybwad, G.L.

    1995-03-01

    The Plasma Technology Directory has two main goals: (1) promote, coordinate, and share plasma technology experience and equipment within the Department of Energy; and (2) facilitate technology transfer to the commercial sector where appropriate. Personnel are averaged first by Laboratory and next by technology area. The technology areas are accelerators, cleaning and etching deposition, diagnostics, and modeling.

  18. Plasma treatment of polydimethylsiloxane

    Microsoft Academic Search

    Michael J. Owen; Patrick J. Smith

    1994-01-01

    Plasma treatment of silicone surfaces is a useful way of increasing wettability to improve adhesion and a first step in producing various organosilicon thin-film composites. Despite numerous earlier studies, there is no consensus on the effect of plasma treatment nor on the mechanism of the subsequent hydrophobic recovery. X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) were used to

  19. Plasma control at JET

    Microsoft Academic Search

    M. Lennholm; T. Budd; R. Felton; M. Gadeberg; A. Goodyear; F. Milani; F. Sartori

    2000-01-01

    Joint European Torus (JET) discharges have plasma currents up to 6 MA and toroidal fields up to 4 T. The plasma parameters during discharges are determined by the action of a number of distinct systems. These systems can be divided into three groups; the toroidal and poloidal field systems; the fuelling systems; and the additional heating systems. The systems can

  20. Heliospheric plasma sheets

    Microsoft Academic Search

    N. U. Crooker; C.-L. Huang; S. M. Lamassa; D. E. Larson; S. W. Kahler; H. E. Spence

    2004-01-01

    As a high-beta feature on scales of hours or less, the heliospheric plasma sheet (HPS) encasing the heliospheric current sheet shows a high degree of variability. A study of 52 sector boundaries identified in electron pitch angle spectrograms in Wind data from 1995 reveals that only half concur with both high-beta plasma and current sheets, as required for an HPS.

  1. 80 Years of Plasma

    Microsoft Academic Search

    2009-01-01

    Irving Langmuir proposed the term 'plasma' in a paper in 1928 (Proc. Natl Acad. Sci. USA14 627–637) to describe a 'region containing balanced charges of ions and electrons'. There does not appear to be any record of the thinking behind this proposal, so it is difficult to be definitive. One idea is that since the Greek word 'plasma' was used

  2. Principles of plasma diagnostics

    Microsoft Academic Search

    Ian H. Hutchinson

    1987-01-01

    Principles of Plasma Diagnostics provides a detailed derivation and discussion of the plasma physics principles on which diagnostics are base, including magnetic measurements, electric probes, refractive index, radiation emission and scattering, and ionic processes. The text is based on first-principles development of the required concepts and includes examples of diagnostics in action taken from fusion research.

  3. Optical plasma diagnostics

    Microsoft Academic Search

    Liliia Trofimovna Lar'kina; Vladimir Semenovich Engel'Sht

    1987-01-01

    The existing methods for the optical diagnostics of low-temperature plasmas are reviewed with particular reference to spectral, schlieren, and interferometric methods, resonance laser fluorescence, holographic interferometry, laser anemometry, and holography of two-phase flows. The methods discussed are used to determine the principal plasma parameters, such as temperature and velocity, atom and electron concentration, and microparticle velocity. The discussion covers the

  4. Principles of plasma diagnostics

    Microsoft Academic Search

    I. H. Hutchinson

    1990-01-01

    This book is a reprint of the 1987 edition (44.003.073). Contents: 1. Plasma diagnostics. 2. Magnetic diagnostics. 3. Plasma particle flux. 4. Refractive-index measurements. 5. Electromagnetic emission by free electrons. 6. Electromagnetic radiation from bound electrons. 7. Scattering of electromagnetic radiation. 8. Ion processes.

  5. Plasma diagnostic reflectometry

    Microsoft Academic Search

    B. I. Cohen; B. B. Afeyan; J. C. Garrison; T. B. Kaiser; N. C. Jr. Luhmann; C. W. Domier; A. E. Chou; S. Baang

    1996-01-01

    Theoretical and experimental studies of plasma diagnostic reflectometry have been undertaken as a collaborative research project between the Lawrence Livermore National Laboratory (LLNL) and the University of California Department of Applied Science Plasma Diagnostics Group under the auspices of the Laboratory Directed Research and Development Program at LLNL. Theoretical analyses have explored the basic principles of reflectometry to understand its

  6. Plasma opening switch

    DOEpatents

    Savage, Mark E. (Albuquerque, NM); Mendel, Jr., Clifford W. (Albuquerque, NM)

    2001-01-01

    A command triggered plasma opening switch assembly using an amplification stage. The assembly surrounds a coaxial transmission line and has a main plasma opening switch (POS) close to the load and a trigger POS upstream from the main POS. The trigger POS establishes two different current pathways through the assembly depended on whether it has received a trigger current pulse. The initial pathway has both POS's with plasma between their anodes and cathodes to form a short across the transmission line and isolating the load. The final current pathway is formed when the trigger POS receives a trigger current pulse which energizes its fast coil to push the conductive plasma out from between its anode and cathode, allowing the main transmission line current to pass to the fast coil of the main POS, thus pushing its plasma out the way so as to establish a direct current pathway to the load.

  7. Neutral Gas Plasma Interactions in Space Plasma

    Microsoft Academic Search

    Kan Liou

    1994-01-01

    A sounding rocket experiment, CRIT-II, involving the injection of shaped-charge barium in ionospheric plasma was conducted on May 7, 1989, to investigate Alfven's critical ionization velocity (CIV) hypothesis in space. The CRIT -II main payload was instrumented to make in situ measurements within the neutral barium beam. Among the detectors, UNH provided three energetic particle detectors and two photometers. The

  8. Boundary Plasma Issues in Burning Plasma Science

    E-print Network

    Pitcher, C. S.

    impurity production 4. screening of impurities 5. burning plasma experiment? #12;(1) Wide Dispersal if strike points are swept (BPX), but Tt will be high impurity production, high Zeff (not desirable mode pressure for H- modes (tight baffling??) · allows efficient pumping to: - remove helium ash - induce SOL

  9. Boundary Plasma Issues in Burning Plasma Science

    E-print Network

    Pitcher, C. S.

    impurity production 4. screening of impurities · why a burning plasma experiment? · BP contribution impurity production, high Zeff (not desirable mode of operation ) #12;···· we know a lot more now than helium ash - induce SOL flow towards divertor - control density · helium exhaust time, i.e. He , limited

  10. Boundary Plasma Issues in Burning Plasma Science

    E-print Network

    impurity production 4. screening of impurities 5. burning plasma experiment? #12;(1) Wide Dispersal points are swept (BPX), but Tt will be high impurity production, high Zeff (not desirable mode- modes (tight baffling??) · allows efficient pumping to: - remove helium ash - induce SOL flow towards

  11. Origins of magnetospheric plasma

    SciTech Connect

    Moore, T.E. (USAF, Geophysics Laboratory, Hanscom AFB, MA (United States))

    1991-01-01

    A review is given of recent (1987-1990) progress in understanding of the origins of plasmas in the earth's magnetosphere. In counterpoint to the early supposition that geomagnetic phenomena are produced by energetic plasmas of solar origin, 1987 saw the publication of a provocative argument that accelerated ionospheric plasma could supply all magnetospheric auroral and ring current particles. Significant new developments of existing data sets, as well as the establishment of entirely new data sets, have improved the ability to identify plasma source regions and to track plasma through the magnetospheric system of boundary layers and reservoirs. These developments suggest that the boundary between ionospheric and solar plasmas, once taken to lie at the plasmapause, actually lies much nearer to the magnetopause. Defining this boundary as the surface where solar wind and ionosphere contribute equally to the plasma, it is referred to herein as the 'geopause'. It is now well established that the infusion of ionospheric O(+) plays a major role in the storm-time distention of the magnetotail and inflation of the inner magnetosphere. After more than two decades of observation and debate, the question remains whether magnetosheric are protons of solar or terrestrial origin. 161 refs.

  12. CHAPTER 1. COLLECTIVE PLASMA PHENOMENA 1 Collective Plasma

    E-print Network

    Callen, James D.

    CHAPTER 1. COLLECTIVE PLASMA PHENOMENA 1 Chapter 1 Collective Plasma Phenomena The properties of a medium are determined by the microscopic processes in it. In a plasma the microscopic processes is actually limited to a distance of order the Debye length in a plasma. On length scales longer than

  13. Space electric propulsion plasmas

    SciTech Connect

    Wilbur, P.J. (Colorado State Univ., Fort Collins, CO (United States). Engineering Research Center); Jahn, R.G. (Princeton Univ., NJ (United States). School of Engineering and Applied Science); Curran, F.C. (National Aeronautics and Space Administration, Cleveland, OH (United States). Lewis Research Center)

    1991-12-01

    This paper reports on electric thrusters which offer the promise of a substantial improvement in performance over that of conventional chemical rockets currently used in space propulsion applications. Thrust is produced in three separate classes of thrusters by: expanding an electrically heated plasma in a nozzle, accelerating a plasma through the application of an electromagnetic body force, or accelerating ions in an electric field. Each of these means of producing thrust involves plasmas that are at once different, phenomenologically rich, and worthy of separate consideration.

  14. Plasma for cancer treatment

    NASA Astrophysics Data System (ADS)

    Keidar, Michael

    2015-06-01

    Plasma medicine is a relatively new field that grew from research in application of low-temperature (or cold) atmospheric plasmas in bioengineering. One of the most promising applications of cold atmospheric plasma (CAP) is cancer therapy. Convincing evidence of CAP selectivity towards the cancer cells has been accumulated. This review summarizes the state of the art of this emerging field, presenting various aspects of CAP application in cancer such as the role of reactive species (reactive oxygen and nitrogen), cell cycle modification, in vivo application, CAP interaction with cancer cells in conjunction with nanoparticles, and computational oncology applied to CAP.

  15. Ultracold neutral plasmas

    SciTech Connect

    Killian, Thomas C.; Rolston, Steven L. [Rice University, Houston, Texas (United States); University of Maryland, College Park (United States)

    2010-03-15

    Plasmas are collections of charged particles that can exhibit an impressively diverse set of collective phenomena. They exist in an extraordinary variety of environments and span a great range of densities and temperatures, from 15 million kelvin in the core of the Sun to 200 K in the ionosphere and from 10{sup 30} particles per cubic centimeter in a white dwarf to 1 particle per cm{sup 3} in interstellar space. They can find application in lighting sources, manufacturing of computer chips, and fusion energy research. Plasmas created in the laboratory are used to replicate and study those that occur naturally and to probe the fundamental and complex behavior of plasmas.

  16. A tunable microwave plasma source for space plasma simulation experiments

    Microsoft Academic Search

    David N. Walker; Dwight Duncan; John A. Stracka; Jeffrey H. Bowles; Carl L. Siefring; Mark M. Baumback; Paul Rodriguez

    1994-01-01

    In laboratory experiments related to space plasma physics it is often desirable to produce plasmas with characteristics as close as possible to various naturally occurring plasma regimes. In the near-earth region space plasma densities typically vary from 103–107 cm?3 and temperatures range from a few tenths of an eV to the order of 1 eV. The plasma parameters of electron

  17. Plasma surface modification of polymers

    NASA Technical Reports Server (NTRS)

    Hirotsu, T.

    1980-01-01

    Thin plasma polymerization films are discussed from the viewpoint of simplicity in production stages. The application of selective, absorbent films and films used in selective permeability was tested. The types of surface modification of polymers discussed are: (1) plasma etching, (2) surface coating by plasma polymerized thin films, and (3) plasma activation surface graft polymerization.

  18. Plasma-based accelerator structures

    SciTech Connect

    Schroeder, Carl B.

    1999-12-01

    Plasma-based accelerators have the ability to sustain extremely large accelerating gradients, with possible high-energy physics applications. This dissertation further develops the theory of plasma-based accelerators by addressing three topics: the performance of a hollow plasma channel as an accelerating structure, the generation of ultrashort electron bunches, and the propagation of laser pulses is underdense plasmas.

  19. Atmospheric pressure plasmas: A review

    Microsoft Academic Search

    Claire Tendero; Christelle Tixier; Pascal Tristant; Jean Desmaison; Philippe Leprince

    2006-01-01

    This article attempts to give an overview of atmospheric plasma sources and their applications. The aim is to introduce, in a first part, the main scientific background concerning plasmas as well as the different atmospheric plasma sources (description, working principle). The second part focuses on the various applications of the atmospheric plasma technologies, mainly in the field of surface treatments.Thus

  20. Michigan Institute for Plasma Sci-

    E-print Network

    Shyy, Wei

    polarization in the skin layer and second harmonic current circu- lating around the main discharge current kinetics and plasma elec- trodynamics, plasma diagnostics, light source science and technology, plasma devices for material processing and plasma system design. Dr. Godyak is a Fellow of the APS

  1. Plasma Waves (2nd edition)

    Microsoft Academic Search

    D G Swanson

    2003-01-01

    To a beginner in plasma physics the subject of waves can be bewildering, with a seeming myriad of different wave modes and ways of approaching them though cold plasma equations, warm plasma equations or kinetic equations. Add to this the intricacies of Landau and cyclotron damping and the fact that real plasmas are rarely uniform and infinite in extent, even

  2. Plasma pyrolysis of toxic waste

    Microsoft Academic Search

    Ph G Rutberg

    2003-01-01

    The comparison of technical economic indexes of different waste treatment methods and plasma pyrolysis is presented in the paper. It testifies that plasma technologies are economically expedient for these purposes. Physical prerequisites allowing realizing plasma technologies are presented. Reliable and economical (70–120 Euro per ton of treated product) plasma generation is the basic condition of the technology realization. In this

  3. Magnetospheric Plasma Physics

    NASA Astrophysics Data System (ADS)

    Mauk, Barry H.

    Magnetospheric Plasma Physics is volume 4 of an ongoing series of review books entitled Developments in Earth and Planetary Sciences organized by the Center for Academic Publications Japan. The series is intended to stress Japanese work; however, the present volume was written by seven internationally selected authors who have reviewed works from a broad range of sources. This volume is composed of articles drawn from five lecture series presented at the Autumn College o f Plasma Physics, International Center for Theoretical Physics, Trieste, Italy, October-November 1979. The audiences for these lecture series were plasma and/or space plasma physicists, or students of the same, and the level and tone of this volume clearly reflect that condition.

  4. Simulation of Fusion Plasmas

    ScienceCinema

    Chris Holland

    2010-01-08

    The upcoming ITER experiment (www.iter.org) represents the next major milestone in realizing the promise of using nuclear fusion as a commercial energy source, by moving into the ?burning plasma? regime where the dominant heat source is the internal fusion reactions. As part of its support for the ITER mission, the US fusion community is actively developing validated predictive models of the behavior of magnetically confined plasmas. In this talk, I will describe how the plasma community is using the latest high performance computing facilities to develop and refine our models of the nonlinear, multiscale plasma dynamics, and how recent advances in experimental diagnostics are allowing us to directly test and validate these models at an unprecedented level.

  5. The plasma state

    NSDL National Science Digital Library

    Space Science Institute

    2005-01-01

    This segment of a tutorial about plasma--the main state of matter in space--deals with what plasma is and how it is formed. Background information on electric and magnetic fields is also included because plasmas interact with these fields. Enlargeable graphics and an interactive game about the four states of matter complement the segment's four pages of text. In the game, students direct falling objects, such as rocks, lightning, and gasoline, into the appropriate state-of-matter slot. The segment also explains why plasma is so rare on Earth and so abundant in space. A concluding vignette explores Hannes Alfven's ongoing influence on space physics. Alfven was a twentieth-century Nobel laureate. Copyright 2005 Eisenhower National Clearinghouse

  6. Princeton Plasma Physics Laboratory

    NSDL National Science Digital Library

    The Princeton Plasma Physics Laboratory: the Fusion Laboratories facilities and mission, including the recent tokamak experiments which resulted in the production of more than 9 million watts of thermonuclear energy.

  7. Accelerating Particles with Plasma

    SciTech Connect

    Litos, Michael; Hogan, Mark

    2014-11-05

    Researchers at SLAC explain how they use plasma wakefields to accelerate bunches of electrons to very high energies over only a short distance. Their experiments offer a possible path for the future of particle accelerators.

  8. Fizeau plasma interferometer

    SciTech Connect

    Frank, A.M.

    1980-01-01

    This paper describes a technique by which the sensitivity of plasma interferometers can be increased. Stabilization and fractional fringe measurement techniques have improved to the point where additional optical sensitivity could be useful. (MOW)

  9. PlasmaLyte.

    PubMed

    Rizoli, Sandro

    2011-05-01

    PlasmaLyte is a family of balanced crystalloid solutions with multiple different formulations available worldwide according to regional clinical practices and preferences. It closely mimics human plasma in its content of electrolytes, osmolality, and pH. These solutions also have additional buffer capacity and contain anions such as acetate, gluconate, and even lactate that are converted to bicarbonate, CO2, and water. The advantages of PlasmaLyte include volume and electrolyte deficit correction while addressing acidosis. It shares the same problems as most other crystalloid fluids (fluid overload, edema with weight gain, lung edema, and worsening of the intracranial pressure). A unique concern is that most formulations contain magnesium, which may affect peripheral vascular resistance, heart rate, and worsen organ ischemia. There are few studies on its use in trauma or hypovolemic shock. There is no evidence that PlasmaLyte is superior to other crystalloids for the prehospital management of traumatic hypovolemia. PMID:21841561

  10. Plasma-Sheath Model

    NASA Astrophysics Data System (ADS)

    Riemann, Karl-Ulrich

    2012-10-01

    In typical gas discharges a quasineutral plasma is shielded from a negativ absorbing wall by a thin positive sheath that is nearly planar and collision-free. The subdivision of ``plasma'' and ``sheath'' was introduced by Langmuir and is based on a small ratio of the electron Debye lenghth ?D to the dominant competing characteristic plasma length l. Depending on the special conditions, l may represent, e.g., the plasma extension, the ionization length, the ion mean free path, the ion gyro radius, or a geometric length. Strictly speaking, this subdivion is possible only in the asymptotic limit ?D/l->0. The asymptotic analysis results in singularities at the ``sheath edge'' closely related to the ``Bohm criterion.'' Due to these singularities a direct smooth matching of the separate plasma and sheath soltions is not possible. To obtain a consistent smooth transition, the singular sheath edge must be bridged by an additinal narrow ``intermediate'' model zone accounting both for plasma processes (e.g., collisions) and for the first build up of space charge. Due to this complexity and to different interpretations of the ``classical'' papers by Langmuir and Bohm, the asymptotic plasma-sheath concept and the definition of the sheath edge were questioned and resulted in controversies during the last two decades. We discuss attempts to re-define the sheath edge, to account for finite values of ?D/l in the Bohm criterion, and demonstrate the consistent matching of plasma and sheath. The investigations of the plasma-sheath transition discussed so far are based on a simplified fluid analysis that cannot account for the essential inhomogeneity of the boundary layer and for the dominant role of slow ions in space charge formation. Therefore we give special emphasis to the kinetic theory of the plasma-sheath transition. Unfortunately this approach results in an additional mathematical difficulty caused by ions with zero velocity. We discuss attempts to avoid this singularity by a modification of the kinetic Bohm criterion and investigate the influence of slow ions on the structure of the plasma-sheath transition. The most important conclusions are illustrated with selected examples.

  11. Plasma jet effects on the ionospheric plasma

    NASA Technical Reports Server (NTRS)

    Moore, T. E.; Arnoldy, R. L.; Cahill, L. J.; Kintner, P. M.

    1983-01-01

    Heavy ion beams were injected into the ionospheric plasma (experiments ARCS 1 and ARCS 2). In ARCS 1, operation of a 25eV argon ion source, mounted on a plasma diagnostic payload, produced an accelerated electron population; broadband electric field turbulence; large, spin synchronized electric field perturbations; and depletions of thermal ions. In ARCS 2, the ion source was deployed upward along the local magnetic field direction away from the diagnostic payload, and observed effects are contained within several meters of the ion source. However, enhanced wave levels near the LHR frequency are observed at distances up to 1 km, as are the injected ions themselves. A measurement of the dominant wavelength of the enhanced waves is consistent with an inference based upon the accelerated electron population seen in ARCS 1. This electron population is not evident during ARCS 2.

  12. Electrostatics of moving plasma

    SciTech Connect

    Ignatov, A. M. [Russian Academy of Sciences, Prokhorov General Physics Institute (Russian Federation)] [Russian Academy of Sciences, Prokhorov General Physics Institute (Russian Federation)

    2013-07-15

    The stability of charge distribution over the surface of a conducting body in moving plasma is analyzed. Using a finite-width plate streamlined by a cold neutralized electron flow as an example, it is shown that an electrically neutral body can be unstable against the development of spontaneous polarization. The plasma parameters at which such instability takes place, as well as the frequency and growth rate of the fundamental mode of instability, are determined.

  13. Plasma Screen Floating Mount

    DOEpatents

    Eakle, Robert F. (New Ellenton, SC); Pak, Donald J. (Martine, GA)

    2004-10-26

    A mounting system for a flat display screen, particularly a plasma display screen, suspends the screen separately in each of the x-, y- and z-directions. A series of frames located by linear bearings and isolated by springs and dampers allows separate controlled movement in each axis. The system enables the use of relatively larger display screens in vehicles in which plasma screen are subject to damage from vibration.

  14. Plasma exudation and asthma

    Microsoft Academic Search

    Carl G. A. Persson

    1988-01-01

    Several pieces of evidence support the view that exudation of plasma into the airway wall and into the airway lumen occurs\\u000a in asthma. Vascular leakage of plasma results from inflammatory mediator-induced separation of endothelial cells in postcapillary\\u000a venules belonging to the tracheobronchial circulation. Whereas proposed mediators of asthma induce reversible leakage, several\\u000a antiasthma drugs exhibit antileakage effects in animals and

  15. Plasmas in Saturn's magnetosphere

    Microsoft Academic Search

    L. A. Frank; B. G. Burek; K. L. Ackerson; J. H. Wolfe; J. D. Mihalov

    1980-01-01

    The solar wind plasma analyzer on board Pioneer 11 proves first observations of low-energy positive ions in the magnetosphere of Saturn. Measurable intensities of ions within the energy per unit charge (E\\/Q) range 100 eV to 8 eV are present over the planetocentric radial distance range approx.4--16 R\\/sub s\\/ in the day-side magnetosphere. The plasmas are found to be rigidly

  16. Plasmas in Saturn's magnetosphere

    NASA Technical Reports Server (NTRS)

    Frank, L. A.; Burek, B. G.; Ackerson, K. L.; Wolfe, J. H.; Mihalov, J. D.

    1980-01-01

    The solar wind plasma analyzer on board Pioneer 2 provides first observations of low-energy positive ions in the magnetosphere of Saturn. Measurable intensities of ions within the energy-per-unit charge (E/Q) range 100 eV to 8 keV are present over the planetocentric radial distance range about 4 to 16 R sub S in the dayside magnetosphere. The plasmas are found to be rigidly corotating with the planet out to distances of at least 10 R sub S. At radial distances beyond 10 R sub S, the bulk flows appear to be in the corotation direction but with lesser speeds than those expected from rigid corotation. At radial distances beyond the orbit of Rhea at 8.8 R sub S, the dominant ions are most likely protons and the corresponding typical densities and temperatures are 0.5/cu cm and 1,000,000 K, respectively, with substantial fluctuations. It is concluded that the most likely source of these plasmas in the photodissociation of water frost on the surface of the ring material with subsequent ionization of the products and radially outward diffusion. The presence of this plasma torus is expected to have a large influence on the dynamics of Saturn's magnetosphere since the pressure ratio beta of these plasmas approaches unity at radial distances as close to the planet as 6.5 R sub S. On the basis of these observational evidences it is anticipated that quasi-periodic outward flows of plasma, accompanied with a reconfiguration of the magnetosphere beyond about 6.5 R sub S, will occur in the local night sector in order to relieve the plasma pressure from accretion of plasma from the rings.

  17. Callisto Plasma Interactions

    NASA Astrophysics Data System (ADS)

    Holmstrom, M.; Lindkvist, J.; Barabash, S. V.

    2013-12-01

    Modeling the interaction between Callisto and Jupiter's magnetosphere is important to understand the origin of the magnetic field perturbations observed by Galileo, potentially related to subsurface oceans. Understanding the plasma environment at Callisto is also important in view of the future JUICE mission. We study the plasma interactions of Callisto using a hybrid model (ions as particles and electrons as a fluid). Included in the model is an ionosphere and conductive sub surface layers. The results are compared to Galileo observations.

  18. Plasma contactor research - 1991

    NASA Astrophysics Data System (ADS)

    Buchholtz, Brett; Williams, John D.; Wilbur, Paul J.

    1992-04-01

    A report describing the operating principles of hollow-cathode-based plasma contactors emitting or collecting electrons from an ambient plasma is summarized. Preliminary experiments conducted to determine the noise generated by these plasma contactors in the emission-current return line and in the plasma near it are described. These noise data are measured as current fluctuations in the return line and to the Langmuir probe and then analyzed using a fast Fourier transform technique. The spectral compositions of the data are characterized using power spectral density plots which are examined to identify possible noise source(s) and production mechanism(s). The precautions taken in the construction and calibration of the instrumentation to assure adequate frequency response are described. Experimental results show that line-current noise levels are typically 2 percent of the electron current being emitted or collected. However, noise levels increase to as much as 20 percent of the electron current at a few electron-collection operating conditions. The frequencies associated with most of the noise were harmonics of the 60 Hz input to system power supplies. Plasma noise had characteristics similar in magnitude and frequency to those for the return-line noise, but they contained additional features at frequencies considered to be related to ion-acoustic instabilities. Also discussed is a new probe positioning system built to facilitate future plasma-contractor research.

  19. Plasma tomography systems for industrial plasma tools

    SciTech Connect

    Shannon, S.C.; Pollack, S.; Holloway, J.P.; Brake, M. [Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Nuclear Engineering and Radiological Sciences

    1996-12-31

    Addressing the geometry constraints that have inhibited the use of optical emission based tomography systems on industrial plasma tools, the University of Michigan has developed a plasma tomography system which uses optical emission spectroscopy (OES) technology and can be operated from a relatively small window compared to the standard Abel geometry previously used by many authors; this change in geometry may make the technique more applicable to industrial plasma tools, which have relatively small windows. The light collection system is based on a rotating point sensor at the surface of the window and reconstructs emissivity from thin wedges of vertically collimated light. This design not only allows for use in small window geometries, but also collects more light than the traditional parallel rays arrangement, thereby providing a better signal to noise ratio for the measurement. This current sensor`s design, results, and a comparison with findings based on Langmuir probe and other OES methods will be presented. Plans for future sensor improvements to allow for multipeak analysis and compatibility with more confining geometries will also be presented.

  20. Plasma electron analysis: Voyager plasma science experiment

    NASA Technical Reports Server (NTRS)

    Sittler, E. C., Jr.

    1983-01-01

    The Plasma Science Experiment (PLS) on the Voyager spacecraft provide data on the plasma ions and electrons in the interplanetary medium and the magnetospheres of the giant planets Jupiter and Saturn. A description of the analysis used to obtain electron parameters (density, temperature, etc.) from the plasma science experiment PLS electron measurements which cover the energy range from 10 eV to 5950 eV is presented. The electron sensor (D cup) and its transmission characteristics are described. A derivation of the fundamental analytical expression of the reduced distribution function F(e) is given. The electron distribution function F(e), used in the moment integrations, can be derived from F(e). Positive ions produce a correction current (ion feedthrough) to the measured electron current, which can be important to the measurements of the suprathermal electron component. In the case of Saturn, this correction current, which can either add to or subtract from the measured electron current, is less than 20% of the measured signal at all times. Comments about the corrections introduced by spacecraft charging to the Saturn encounter data, which can be important in regions of high density and shadow when the spacecraft can become negatively charged are introduced.

  1. Fresh-frozen plasma, pathogen-reduced single-donor plasma or bio-pharmaceutical plasma?

    Microsoft Academic Search

    Peter Hellstern

    2008-01-01

    Three types of therapeutic plasma are available that differ in their manufacturing processes, composition, clinical efficacy, and side effects. Quarantine-stored, not pathogen-reduced fresh-frozen plasma (QFFP) is prepared from single whole blood or plasma donations. The manufacture of pathogen-reduced single-donor plasmas such as methylene blue-light treated (MLP) or amotosalen-ultraviolet light treated plasma (ALP) involves the addition of a chemical followed by

  2. Plasma wakefield acceleration in self-ionized gas or plasmas.

    PubMed

    Deng, S; Barnes, C D; Clayton, C E; O'Connell, C; Decker, F J; Erdem, O; Fonseca, R A; Huang, C; Hogan, M J; Iverson, R; Johnson, D K; Joshi, C; Katsouleas, T; Krejcik, P; Lu, W; Marsh, K A; Mori, W B; Muggli, P; Tsung, F

    2003-10-01

    Tunnel ionizing neutral gas with the self-field of a charged particle beam is explored as a possible way of creating plasma sources for a plasma wakefield accelerator [Bruhwiler et al., Phys. Plasmas (to be published)]. The optimal gas density for maximizing the plasma wakefield without preionized plasma is studied using the PIC simulation code OSIRIS [R. Hemker et al., in Proceeding of the Fifth IEEE Particle Accelerator Conference (IEEE, 1999), pp. 3672-3674]. To obtain wakefields comparable to the optimal preionized case, the gas density needs to be seven times higher than the plasma density in a typical preionized case. A physical explanation is given. PMID:14683089

  3. Plasma plume propagation characteristics of pulsed radio frequency plasma jet

    SciTech Connect

    Liu, J. H.; Liu, X. Y.; Hu, K.; Liu, D. W.; Lu, X. P. [Advanced Electromagnetic Engineering and Technology Laboratory, Huazhong University of Science and Technology, WuHan, HuBei 430074 (China); Iza, F.; Kong, M. G. [Department of Electronic and Electrical Engineering, Loughborough University, Leicestershire LE11 3TU (United Kingdom)

    2011-04-11

    A 4 cm long helium cold atmospheric pressure plasma jet with pulsed radio frequency (rf) excitation was obtained by a copper electrode inside a quartz tube. The plasma bullet propagation characteristics common to the microseconds direct current pulse and kilohertz plasma jet is not observed in this case. The space-, time-, and wavelength-resolved optical emission profiles suggest the pulsed rf plasma channel out of the tube was strengthened by ions and metastables with longer life time than the rf period, and the plasma propagation was actually an illumination of the plasma channel caused by energetic electrons accelerated along the channel.

  4. Plasma plume propagation characteristics of pulsed radio frequency plasma jet

    NASA Astrophysics Data System (ADS)

    Liu, J. H.; Liu, X. Y.; Hu, K.; Liu, D. W.; Lu, X. P.; Iza, F.; Kong, M. G.

    2011-04-01

    A 4 cm long helium cold atmospheric pressure plasma jet with pulsed radio frequency (rf) excitation was obtained by a copper electrode inside a quartz tube. The plasma bullet propagation characteristics common to the microseconds direct current pulse and kilohertz plasma jet is not observed in this case. The space-, time-, and wavelength-resolved optical emission profiles suggest the pulsed rf plasma channel out of the tube was strengthened by ions and metastables with longer life time than the rf period, and the plasma propagation was actually an illumination of the plasma channel caused by energetic electrons accelerated along the channel.

  5. Plasmas in High-Density Medium - Supercritical fluid plasma and Cryogenic plasma

    NASA Astrophysics Data System (ADS)

    Terashima, Kazuo

    2011-10-01

    Recently, there has been a lot of attention to plasmas in high-density medium as novel plasmas from the views points of not only pure sciences but also various technologies. In this talk, two topics, supercritical fluid plasma and cryogenic plasma, will be discussed. First, plasmas generated in supercritical fluids (supercritical fluid plasma) provide a new reaction field that combines the high reactivity of plasmas with the unique characteristics of supercritical fluids, i.e. molecular clustering and density fluctuations near the critical point. An overview of the earliest studies on plasmas generated in supercritical fluids to recent advances in the field, including synthesis of novel nanomaterials such as highly-order diamondoid (diamond molecules), will be given. Second, continuing to thermal plasma (gas temperature Tg higher than a few thousands to millions of K) and low temperature plasma (Tg ranging from a few hundreds to thousands of K), plasma in a third range of gas temperatures (Tg lower than 300 K) is called cryogenic plasma (or cryoplasma) to distinguish it from thermal and low-temperature plasmas. In our group, the gas temperature of the plasma can be continuously controlled below room temperature (RT) down to a cryogenic temperature such as the boiling point of helium (4 K). In addition to the diagnostics, the application of cryogenic plasma to nanoporous material processing (low damage ashing of low-k materials) will be discussed. This work was supported financially in part by Grants-in-Aid.

  6. Plasma Colloquium Travel Grant Program

    SciTech Connect

    Hazeltine, R.D.

    1998-09-14

    OAK B188 Plasma Colloquium Travel Grant Program. The purpose of the Travel Grant Program is to increase the awareness of plasma research. The new results and techniques of plasma research in fusion plasmas, plasma processing space plasmas, basic plasma science, etc, have broad applicability throughout science. The benefits of these results are limited by the relatively low awareness and appreciation of plasma research in the larger scientific community. Whereas spontaneous interactions between plasma scientists and other scientists are useful, a focused effort in education and outreach to other scientists is efficient and is needed. The academic scientific community is the initial focus of this effort, since that permits access to a broad cross-section of scientists and future scientists including undergraduates, graduate students, faculty, and research staff.

  7. Low Temperature Plasma Medicine

    NASA Astrophysics Data System (ADS)

    Graves, David

    2013-10-01

    Ionized gas plasmas near room temperature are used in a remarkable number of technological applications mainly because they are extraordinarily efficient at exploiting electrical power for useful chemical and material transformations near room temperature. In this tutorial address, I will focus on the newest area of low temperature ionized gas plasmas (LTP), in this case operating under atmospheric pressure conditions, in which the temperature-sensitive material is living tissue. LTP research directed towards biomedical applications such as sterilization, surgery, wound healing and anti-cancer therapy has seen remarkable growth in the last 3-5 years, but the mechanisms responsible for the biomedical effects have remained mysterious. It is known that LTP readily create reactive oxygen species (ROS) and reactive nitrogen species (RNS). ROS and RNS (or RONS), in addition to a suite of other radical and non-radical reactive species, are essential actors in an important sub-field of aerobic biology termed ``redox'' (or oxidation-reduction) biology. I will review the evidence suggesting that RONS generated by plasmas are responsible for their observed therapeutic effects. Other possible bio-active mechanisms include electric fields, charges and photons. It is common in LTP applications that synergies between different mechanisms can play a role and I will review the evidence for synergies in plasma biomedicine. Finally, I will address the challenges and opportunities for plasma physicists to enter this novel, multidisciplinary field.

  8. Inductive Plasma Accelerator (IPA)

    NASA Astrophysics Data System (ADS)

    Ziemba, Timothy; Slough, John

    2005-10-01

    The Inductive Plasma Accelerator (IPA) is a plasma accelerator/interaction experiment currently under constuction at MSNW. The accelerator will be capable of launching a Field Reversed Configuration (FRC) plasmoid having a mass of up to 0.2 mg with a diameter no larger than about 10 cm. In addition, the accelerator will be designed to attain plasma/plasmoid velocities up to 300 km/s while maintaining high uniformity and purity. Two IPAs will be arranged on a test bed to perform FRC merging experiments. In addition, an interaction chamber will be constucted to produce and implode a plasma liner for enhanced compression experiments on the merged FRCs thus providing the first experimental test of the plasma liner fusion concept. 2D MHD simulations show expected densities of > 10^22 m-3 with ion temperatures in excess of 800 eV for the merging FRCs. The status of design and construction of the experiment and additional simulation results will be presented

  9. The Wonders of Plasma

    NASA Astrophysics Data System (ADS)

    Reardon, Jim; Sprott, Clint

    2004-11-01

    The ongoing Wonders of Physics outreach program at the University of Wisconsin has teamed up with the new Center for Magnetic Self-Organization of Laboratory and Astrophysical Plasmas (CMSO), an NSF Physics Frontier Center, in a variety of outreach efforts intended to attract students to plasma physics. Chief among these efforts are a live-action calculus competition--the ``Integration Bee''--in which students compete for prizes by doing integrals at the blackboard, and a video, tentatively entitled the ``Wonders of Plasma,'' which introduces CMSO-related plasma physics to a high-school level audience. Meanwhile, the Wonders of Physics continues to ``win fans for physics'' by putting on entertaining and informative shows before live audiences at the University of Wisconsin and elsewhere. Approximately 10,000 people have seen a Wonders of Physics show since the last APS DPP conference. Several new fusion-related demonstrations have been added to the Wonders of Physics Traveling Show in the past year. Some of them can be seen at the conference at the Plasma Expo on Thursday and Friday. This work supported by US DOE and NSF.

  10. Plasma coal reprocessing

    NASA Astrophysics Data System (ADS)

    Messerle, V. E.; Ustimenko, A. B.

    2013-12-01

    Results of many years of investigations of plasma-chemical technologies for pyrolysis, hydrogenation, thermochemical preparation for combustion, gasification, and complex reprocessing of solid fuels and hydrocarbon gas cracking are represented. Application of these technologies for obtaining the desired products (hydrogen, industrial carbon, synthesis gas, valuable components of the mineral mass of coal) corresponds to modern ecological and economical requirements to the power engineering, metallurgy, and chemical industry. Plasma fuel utilization technologies are characterized by the short-term residence of reagents within a reactor and the high degree of the conversion of source substances into the desired products without catalyst application. The thermochemical preparation of the fuel to combustion is realized in a plasma-fuel system presenting a reaction chamber with a plasmatron; and the remaining plasma fuel utilization technologies, in a combined plasma-chemical reactor with a nominal power of 100 kW, whose zone of the heat release from an electric arc is joined with the chemical reaction zone.

  11. Partial pressure analysis of plasmas

    SciTech Connect

    Dylla, H.F.

    1984-11-01

    The application of partial pressure analysis for plasma diagnostic measurements is reviewed. A comparison is made between the techniques of plasma flux analysis and partial pressure analysis for mass spectrometry of plasmas. Emphasis is given to the application of quadrupole mass spectrometers (QMS). The interface problems associated with the coupling of a QMS to a plasma device are discussed including: differential-pumping requirements, electromagnetic interferences from the plasma environment, the detection of surface-active species, ion source interactions, and calibration procedures. Example measurements are presented from process monitoring of glow discharge plasmas which are useful for cleaning and conditioning vacuum vessels.

  12. Plasma physics in Latin America.

    NASA Astrophysics Data System (ADS)

    Rodrigo, A. B.

    1995-02-01

    The status of plasma physics in Latin America is reviewed. The review surveys the history and present situation of the regional activities in high-temperature plasma research, plasma astrophysics, and technological applications of plasma physics. In particular, it presents data on the trends of evolution of scientific staff, annual operating budget, and publication rate for the major Latin American plasma groups during the decade 1983 - 1992. On this basis, the prospects for further growth and the potential for regional contribution to the mainstream of international plasma research and development are discussed.

  13. Plasma effects on subcellular structures

    SciTech Connect

    Gweon, Bomi; Kim, Dan Bee; Jung, Heesoo; Choe, Wonho [Department of Physics, Korea Advanced Institute of Science and Technology, 335 Gwahangno, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Kim, Daeyeon [Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, 335 Gwahangno, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Shin, Jennifer H. [Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, 335 Gwahangno, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology, 335 Gwahangno, Yuseong-gu, Daejeon 305-701 (Korea, Republic of)

    2010-03-08

    Atmospheric pressure helium plasma treated human hepatocytes exhibit distinctive zones of necrotic and live cells separated by a void. We propose that plasma induced necrosis is attributed to plasma species such as oxygen radicals, charged particles, metastables and/or severe disruption of charged cytoskeletal proteins. Interestingly, uncharged cytoskeletal intermediate filaments are only minimally disturbed by plasma, elucidating the possibility of plasma induced electrostatic effects selectively destroying charged proteins. These bona fide plasma effects, which inflict alterations in specific subcellular structures leading to necrosis and cellular detachment, were not observed by application of helium flow or electric field alone.

  14. Plasma effects on subcellular structures

    NASA Astrophysics Data System (ADS)

    Gweon, Bomi; Kim, Daeyeon; Kim, Dan Bee; Jung, Heesoo; Choe, Wonho; Shin, Jennifer H.

    2010-03-01

    Atmospheric pressure helium plasma treated human hepatocytes exhibit distinctive zones of necrotic and live cells separated by a void. We propose that plasma induced necrosis is attributed to plasma species such as oxygen radicals, charged particles, metastables and/or severe disruption of charged cytoskeletal proteins. Interestingly, uncharged cytoskeletal intermediate filaments are only minimally disturbed by plasma, elucidating the possibility of plasma induced electrostatic effects selectively destroying charged proteins. These bona fide plasma effects, which inflict alterations in specific subcellular structures leading to necrosis and cellular detachment, were not observed by application of helium flow or electric field alone.

  15. Design of a Plasma Injector for a Pulsed Plasma Accelerator

    NASA Technical Reports Server (NTRS)

    Cassibry, J. T.; Thio, Y. C. F.; Markusic, T. E.; Sommers, J.; Rodgers, Stephen L. (Technical Monitor)

    2002-01-01

    In recent years, a pulsed plasma accelerator has been proposed as a candidate stand-off driver for the formation of an imploding liner in magnetized target fusion. For a near-term physics exploratory experiment to study the feasibility of this standoff approach, a plasma accelerator has been proposed that requires the controlled introduction and preparation of the initial plasma for acceleration. This includes uniform injection of the propellant downstream of the breech with a high degree of ionization. The design of a plasma feed is presented, which injects a high conductivity, highly collisional propellant transverse to the conductor. The plasma injector is designed to establish an initial plasma with a moderate Hall parameter at the trailing edge of the plasma slug, high Hall parameter behind the slug for magnetic insulation, and a short diffusion length in comparison with characteristic dimensions of the plasma slug to avoid propellant loss at the trailing edge.

  16. Nonequilibrium lighting plasmas

    SciTech Connect

    Dakin, J.T. (GE Lighting, Nela Park, Cleveland, OH (US))

    1991-12-01

    In this paper the science of a variety of devices employing nonequilibrium lighting plasmas is reviewed. The devices include the fluorescent lamp, the low-pressure sodium lamp, the neon sign, ultraviolet lamps, glow indicators, and a variety of devices used by spectroscopists, such as the hollow cathode light source. The plasma conditions in representative commercial devices are described. Recent research on the electron gas, the role of heavy particles, spatial and temporal inhomogeneities, and new electrodeless excitation schemes is reviewed. Areas of future activity are expected to be in new applications of high-frequency electronics to commercial devices, new laser-based diagnostics of plasma conditions, and more sophisticated models requiring more reliable and extensive rate coefficient data.

  17. Deflagration plasma thruster

    NASA Technical Reports Server (NTRS)

    Cheng, D. Y.; Chang, C. N.

    1984-01-01

    This paper introduces the application of the magnetized plasma deflagration process to space propulsion. The deflagration process has the unique capability of efficiently converting input energy into kinetic energy in the accelerating direction. To illustrate the totally divergent characters of 'snowplow' detonation and deflagration discharges, examples of the differences between deflagration and detonation 'snowplow' discharges are expressed in terms of current densities, temperature, and particle velocities. Magnetic field profiles of the deflagration mode of discharges are measured. Typical attainable plasma characteristics are described in terms of velocity, electron temperature, and density, as well as measurement techniques. Specific impulses measured by piezo-electric probe and pendulum methods are presented. The influence of the transmission line in the discharge circuits on plasma velocity is measured by means of a microwave time-of-flight method. The results for the deflagration thruster are compared with other space thrusters. Further research areas are identified.

  18. Glossary of Plasma Physics

    NSDL National Science Digital Library

    From the Princeton Plasma Physics Laboratory's FusEdWeb: Fusion Energy Educational Web Site, this glossary of plasma physics "seeks to provide plain-language definitions of over 3600 frequently used technical terms in Plasma Physics (all areas) and Fusion Energy Research." The glossary is intended to help facilitate discussion "between experts and non-experts, and even between experts in different subfields." Users may search, submit new terms for review by editors, or browse alphabetically for terms in fields including scientific vocabulary, names of research facilities, experimental machines and devices used, names of researchers, key mathematical symbols, and acronyms. Over a thousand of these terms are fully defined on-site, and references are provided for looking up most of the remaining terms.

  19. Perturbations in a plasma

    E-print Network

    Evangelos Chaliasos

    2005-10-20

    The perturbations of a homogeneous non-relativistic two-component plasma are studied in the Coulomb gauge. Starting from the solution found [2] of the equations of electromagnetic self consistency in a plasma [1], we add small perturbations to all quantities involved, and we enter the perturbed quantities in the equations, keeping only the first order terms in the perturbations. Because the unperturbed quantities are solutions of the equations, they cancel each other, and we are left with a set of 12 linear equations for the 12 perturbations (unknown quantities). Then we solve this set of linearized equations, in the approximation of small ratio of the masses of electrons over those of ions, and under the assumption that the plasma remains homogeneous.

  20. Callisto plasma interaction

    NASA Astrophysics Data System (ADS)

    Lindkvist, Jesper; Holmström, Mats; Fatemi, Shahab; Barabash, Stas

    2014-05-01

    Modeling the interaction between Callisto and Jupiter's magnetosphere is important to understand the origin of the magnetic field perturbations observed by Galileo, potentially related to subsurface oceans. By using a hybrid plasma solver (ions as particles and electrons as a fluid), we have varied the internal conductivity of Callisto, and compared with magnetometer data from a flyby (C9) by the Galileo spacecraft. We focus solely on the case when Callisto has been observed to have no ionosphere. In Callisto's orbit around Jupiter, the plasma environment will vary, and a comparative study has been conducted for the different regions it encounters. Understanding the plasma environment at Callisto is also important in view of the future JUICE mission.

  1. Large area plasma source

    NASA Technical Reports Server (NTRS)

    Foster, John (Inventor); Patterson, Michael (Inventor)

    2008-01-01

    An all permanent magnet Electron Cyclotron Resonance, large diameter (e.g., 40 cm) plasma source suitable for ion/plasma processing or electric propulsion, is capable of producing uniform ion current densities at its exit plane at very low power (e.g., below 200 W), and is electrodeless to avoid sputtering or contamination issues. Microwave input power is efficiently coupled with an ionizing gas without using a dielectric microwave window and without developing a throat plasma by providing a ferromagnetic cylindrical chamber wall with a conical end narrowing to an axial entrance hole for microwaves supplied on-axis from an open-ended waveguide. Permanent magnet rings are attached inside the wall with alternating polarities against the wall. An entrance magnet ring surrounding the entrance hole has a ferromagnetic pole piece that extends into the chamber from the entrance hole to a continuing second face that extends radially across an inner pole of the entrance magnet ring.

  2. Plasma Simulation Program

    SciTech Connect

    Greenwald, Martin

    2011-10-04

    Many others in the fusion energy and advanced scientific computing communities participated in the development of this plan. The core planning team is grateful for their important contributions. This summary is meant as a quick overview the Fusion Simulation Program's (FSP's) purpose and intentions. There are several additional documents referenced within this one and all are supplemental or flow down from this Program Plan. The overall science goal of the DOE Office of Fusion Energy Sciences (FES) Fusion Simulation Program (FSP) is to develop predictive simulation capability for magnetically confined fusion plasmas at an unprecedented level of integration and fidelity. This will directly support and enable effective U.S. participation in International Thermonuclear Experimental Reactor (ITER) research and the overall mission of delivering practical fusion energy. The FSP will address a rich set of scientific issues together with experimental programs, producing validated integrated physics results. This is very well aligned with the mission of the ITER Organization to coordinate with its members the integrated modeling and control of fusion plasmas, including benchmarking and validation activities. [1]. Initial FSP research will focus on two critical Integrated Science Application (ISA) areas: ISA1, the plasma edge; and ISA2, whole device modeling (WDM) including disruption avoidance. The first of these problems involves the narrow plasma boundary layer and its complex interactions with the plasma core and the surrounding material wall. The second requires development of a computationally tractable, but comprehensive model that describes all equilibrium and dynamic processes at a sufficient level of detail to provide useful prediction of the temporal evolution of fusion plasma experiments. The initial driver for the whole device model will be prediction and avoidance of discharge-terminating disruptions, especially at high performance, which are a critical impediment to successful operation of machines like ITER. If disruptions prove unable to be avoided, their associated dynamics and effects will be addressed in the next phase of the FSP.

  3. Complex plasmas: I. complex plasmas as unusual state of matter

    Microsoft Academic Search

    V. N. Tsytovich; G. E. Morfill; H. Thomas

    2002-01-01

    This paper opens a series of review papers devoted to the physics of the so-called complex plasmas. The review contains a\\u000a description of new physical phenomena met in dusty plasmas and complex plasmas. The term complex plasma is used for a state\\u000a where some components (dust) are in crystal or liquid state, while the others (electron, ions, and neutral atoms)

  4. Plasma surface cleaning in a microwave plasma source

    Microsoft Academic Search

    C. C. Tsai; W. D. Nelson; H. H. Haselton; D. E. Schechter; L. M. Thompson; V. B. Campbell; A. L. Glover; J. M. Googin

    1994-01-01

    A microwave electron cyclotron resonance (ECR) plasma source has been operated to produce reactive plasmas of oxygen and its mixture with argon. Aluminum samples (0.95 cm by 1.9 cm) were coated with thin films (<20 μm in thickness) of Shell Vitrea oil and cleaned by using such reactive plasmas. The plasma cleaning was done in discharge conditions of microwave power

  5. Plasma diagnostic reflectometry

    SciTech Connect

    Cohen, B.I.; Afeyan, B.B.; Garrison, J.C.; Kaiser, T.B. [Lawrence Livermore National Lab., CA (United States); Luhmann, N.C. Jr.; Domier, C.W.; Chou, A.E.; Baang, S. [California Univ., Davis, CA (United States). Dept. of Applied Science

    1996-02-26

    Theoretical and experimental studies of plasma diagnostic reflectometry have been undertaken as a collaborative research project between the Lawrence Livermore National Laboratory (LLNL) and the University of California Department of Applied Science Plasma Diagnostics Group under the auspices of the Laboratory Directed Research and Development Program at LLNL. Theoretical analyses have explored the basic principles of reflectometry to understand its limitations, to address specific gaps in the understanding of reflectometry measurements in laboratory experiments, and to explore extensions of reflectometry such as ultra-short-pulse reflectometry. The theory has supported basic laboratory reflectometry experiments where reflectometry measurements can be corroborated by independent diagnostic measurements.

  6. Plasma Facing Components

    NASA Astrophysics Data System (ADS)

    Ulrickson, Michael

    2005-10-01

    Energy escapes from a magnetically confined plasma by convection and diffusion from closed flux regions to open field lines where it is transported to solid surfaces on the device walls. Particle and energy transport along the field lines is much more rapid than transport perpendicular to the field. This means the flux of power and particles on surfaces is quite narrow. Extremely high heat flux can be mitigated by tilting the plasma facing surface, spreading the magnetic field, and adding radiating impurities. Even so the peak heat flux can be in the range of 10-30 MW/m^2. While this heat flux can be removed by structures having adequate thermal conductivity and aggressive cooling, the existence of severe intermittent heat flux 10 to 100 times higher limits the choice of materials and heat sink design. Future fusion devices will have to operate successfully with particle fluence hundreds of times greater than existing devices, and fusion reactor grade plasmas will add energetic neutron damage to the picture. Advances in either materials or design of plasma facing components (PFCs) have had a profound effect on core plasma performance. Early advances relied on selection of carbon based materials that had good thermal conductivity and no melting rather than refractory metals. Carbon fiber reinforced carbon composites provided further performance improvement. Divertor plasmas allowed exploration of plasma sweeping and more effective particle control, but concentrated the heat flux onto a smaller region. Hydrogen retention in carbon is one of the challenges facing the next generation of fusion devices. Impurity shielding in divertor plasmas allows all metal PFCs to be considered. Engineering of high Z refractory metal PFCs with active cooling has matured for use on long pulse devices. Exploratory studies have shown that liquid PFCs may be able to remove high heat flux with no erosion or nuclear damage issues. The major issue for liquid surfaces is control of the magneto-hydrodynamic interaction between the liquid and the spatially and temporally varying fields in a fusion device. This paper will review the advances that have enabled fusion devices and examine the paths that are likely to meet the needs of future devices.

  7. Compression of spinning plasma

    NASA Astrophysics Data System (ADS)

    Geyko, Vasily; Fisch, Nathaniel

    2014-10-01

    Adiabatic compression of a spinning plasma in cylindrical geometry is studied in thermodynamical limit. Compared to spinning neutral gas, additional electrostatic energy of charge separation yields to increased heat capacity for both axial and longitudinal compressions. Radial compression of plasma with external axial magnetic field is also considered. The obtained results can be used as thermodynamical estimations for z-pinch compression. This work was supported by DOE Contract No. DE-AC02-09CH11466, and by NNSA SSAA Grant No. DE-FG52-08NA28553.

  8. QED Plasma and Magnetars

    E-print Network

    Marat Freytsis; Samuel E. Gralla

    2015-04-06

    Magnetars are surrounded by diffuse plasma in magnetic field strengths well above the quantum electrodynamic critical value. We derive equations of "quantum force-free electrodynamics" for this plasma using effective field theory arguments. We argue that quantum effects do not modify the large scale structure of the magnetosphere, and in particular that the spin-down rate does not deviate significantly from the classical result. We provide definite evolution equations that can be used to explore potentially important small-scale corrections, such as shock formation, which has been proposed as a mechanism for both burst and quiescent emission from magnetars.

  9. QED Plasma and Magnetars

    E-print Network

    Freytsis, Marat

    2015-01-01

    Magnetars are surrounded by diffuse plasma in magnetic field strengths well above the quantum electrodynamic critical value. We derive equations of "quantum force-free electrodynamics" for this plasma using an effective field theory arguments. We argue that quantum effects do not modify the large scale structure of the magnetosphere, and in particular that the spin-down rate does not deviate significantly from the classical result. We provide definite evolution equations that can be used to explore potentially important small-scale corrections, such as shock formation, which has been proposed as a mechanism for both burst and quiescent emission from magnetars.

  10. Burning Plasma Science Workshop Astrophysics and Laboratory Plasmas

    E-print Network

    : NASA/Trace #12;Burning Plasma Science Workshop Austin, TX - Tuesday, Dec. 12, 2000 The dynamical Sun ... Credit: NASA/Trace #12;Burning Plasma Science Workshop Austin, TX - Tuesday, Dec. 12, 2000 More distant astrophysical plasmas ... The Crab nebula: soft X-ray & optical images Cen_A: 1-3keV & 13cm images PKS_0637

  11. A plasma receiving dipole antenna

    SciTech Connect

    Minaev, I. M.; Gusein-zade, N. G. [Russian Academy of Sciences, Prokhorov Institute of General Physics (Russian Federation); Rukhadze, K. Z. [Moscow State Institute of Radio Engineering, Electronics, and Automation (Russian Federation)

    2010-10-15

    Results from experimental studies of a short-wave plasma dipole transceiver antenna are presented. The efficiency of the plasma receiving antenna is estimated, and the optimal frequency range for excitation and reception under the given experimental conditions is determined.

  12. The plasma sheet boundary layer

    NASA Technical Reports Server (NTRS)

    Eastman, T. E.; Frank, L. A.; Peterson, W. K.; Lennartsson, W.

    1984-01-01

    A spatially distinct, temporally variable, transition region between the magnetotail lobes and the central plasma sheet designated the plasma sheet boundary layer has been identified from a survey of particle spectra and three-dimensional distributions as sampled by the ISEE 1 LEPEDEA. The instrumentation and data presentation are described, and the signatures of the magnetotail plasma regimes are presented and discussed for the central plasma sheet and lobe and the plasma sheet boundary layer. Comparisons of plasma parameters and distribution fucntions are made and the evolution of ion velocity distributions within the plasma sheet boundary layer is discussed. The spatial distribution of the plasma sheet boundary layer is considered and ion composition measurements are presented.

  13. A microwave plasma cleaning apparatus

    NASA Technical Reports Server (NTRS)

    Tsai, C. C.; Nelson, W. D.; Schechter, D. E.; Thompson, L. M.; Glover, A. L.

    1995-01-01

    In a microwave electron cyclotron resonance plasma source, reactive plasmas of oxygen and its mixtures of argon have been used for evaluating plasma cleaning technologies. Small aluminum samples (0.95 x 1.9 cm) were coated with thin films (less than or equal to 20 micrometers in thickness) of Shell Vitrea oil and cleaned with reactive plasmas. The discharge parameters, such as gas pressure, magnetic field, substrate biasing, and microwave power, were varied to change cleaning conditions. A mass spectroscopy (or residual gas analyzer) was used to monitor the status of plasma cleaning. Mass loss of the samples after plasma cleaning was measured to estimate cleaning rates. Measured cleaning rates of low-pressure (0.5-m torr) argon/oxygen plasmas were as high as 2.7 micrometers/min. X-ray photoelectron spectroscopy was used to determine cleanliness of the sample surfaces. In this paper, significant results of the plasma cleaning are reported and discussed.

  14. Theory of the unmagnetized plasma.

    NASA Technical Reports Server (NTRS)

    Montgomery, D. C.

    1971-01-01

    The Vlasov mathematical model of a plasma, which has come to be thought more useful than any other in describing the dynamical behavior of the majority of plasmas of interest, is first examined. Macroscopic variables and moment equations; linear electrostatics solutions; plasma oscillations, ion acoustic waves, and linear instabilities are treated, as well as external fields, 'test' charges, and nonlinear Vlasov phenomena. Plasmas are statistically described, and attention is given to the kinetic theory of the stable, uniform plasma and the Balescu-Lenard equation; two-time ensemble averages and fluctuation spectra in stable plasmas; the kinetic theory of the unstable plasma; and ensembles of Vlasov plasmas. Some illustrative experiments are described. Four appendixes deal with the electrostatic approximation and transverse waves; solution of the linearized Vlasov equation in a magnetic field; estimates of correlation functions from thermal equilibrium; and equivalence of spatially uniform BBGKY and Klimontovich correlations.

  15. Plasma model for charging damage

    SciTech Connect

    Vella, M.C. [Electro-Graph, Inc., Carlsbad, CA (United States); Lukaszek, W. [Wafer Charging Monitors, Woodside, CA (United States); Current, M.I. [Applied Materials, Santa Clara, CA (United States). Implant Division; Tripsas, N.H. [Advanced Micro Devices, Sunnyvale, CA (United States)

    1994-07-01

    The mechanism responsible for charging damage is treated as beam/plasma driven differences in local floating potentials on the process surface. A cold plasma flood is shown to limit these potential differences. Beam/plasma J-V characteristics obtained with CHARM2 in a high current implanter are fit with the theory. With flood OFF, the fit corresponds to plasma buildup over the target surface.

  16. Experiments on Cryogenic Complex Plasma

    SciTech Connect

    Ishihara, O.; Sekine, W.; Kubota, J.; Uotani, N.; Chikasue, M.; Shindo, M. [Faculty of Engineering, Yokohama National University Yokohama, 240-8501 (Japan)

    2009-11-10

    Experiments on a cryogenic complex plasma have been performed. Preliminary experiments include production of a plasma in a liquid helium or in a cryogenic helium gas by a pulsed discharge. The extended production of a plasma has been realized in a vapor of liquid helium or in a cryogenic helium gas by rf discharge. The charge of dust particles injected in such a plasma has been studied in detail.

  17. Controlled zone microwave plasma system

    DOEpatents

    Ripley, Edward B. (Knoxville, TN); Seals, Roland D. (Oak Ridge, TN); Morrell, Jonathan S. (Knoxville, TN)

    2009-10-20

    An apparatus and method for initiating a process gas plasma. A conductive plate having a plurality of conductive fingers is positioned in a microwave applicator. An arc forms between the conductive fingers to initiate the formation of a plasma. A transport mechanism may convey process materials through the plasma. A spray port may be provided to expel processed materials.

  18. Laser-produced annular plasmas

    Microsoft Academic Search

    F. Veloso; H. Chuaqui; R. Aliaga-Rossel; M. Favre; I. H. Mitchell; E. Wyndham

    2006-01-01

    A new technique is presented for the formation of annular plasmas on a metal surface with a high-power laser using a combination of axicon and converging lenses. The annular plasma formed on a titanium target in a chamber of hydrogen gas was investigated using schlieren imaging and Mach Zehnder interferometry. Expansion of the plasma was shown to be anisotropic with

  19. The plasmas of rocket flight

    Microsoft Academic Search

    W. Balwanz

    1961-01-01

    The plasmas attending a rocket in flight vary widely in charge density and size depending upon the source of the plasma and the altitude of operation. Such a plasma, i.e., a medium containing equal numbers of positive and negative charge so that it is electrically neutral in its totality, interacts with electromagnetic signals causing reflection, refraction and absorption. The solution

  20. Fusion plasma diagnostics with microwaves

    Microsoft Academic Search

    Hans J Hartfuss

    2010-01-01

    An introductory overview is given on the established methods of probing magnetically confined hot fusion plasmas with microwaves in the mm and sub-mm wavelength regions. Since the plasma dielectric properties are mainly determined by the electron component of the plasma, primarily information on this component is being achieved. The methods can be divided into active and passive diagnostics. Applying the

  1. Solar array arcing in plasmas

    Microsoft Academic Search

    Dale C. Ferguson

    1990-01-01

    Solar cells in space plasma conditions are known to arc into the plasma when the interconnects are at a negative potential of a few hundred volts, relative to plasma potential. For cells with silver-coated interconnects, a threshold voltage for arcing exists at about -230 V, as found in both ground and LEO experiments. The arc rate beyond the threshold voltage

  2. Microwave Interferometry for Plasma Studies

    Microsoft Academic Search

    L. C. Robinson; L. E. Sharp

    1963-01-01

    A microwave interferometer is described. The advantage of using ; muicrowave probes is the minimal perturbation of the plasma. To a wave of ; frequency greater than the electron plasma frequency the plasma behaves like a ; dielectric, causing a change in the path which yields the average electron ; density. The attenuation of the probing wave can give the

  3. Dynamical processes in complex plasmas

    Microsoft Academic Search

    A Piel; A Melzer

    2002-01-01

    In this review, a systematic overview of dynamical processes in complex (dusty) plasmas is given. Complex plasmas consist of electrons, ions, neutrals, and microparticles of nanometre to micrometre size, which are responsible for the unusual properties of this kind of plasmas, such as the formation of liquid or solid phases at strong electrostatic coupling. The examples represent the progress in

  4. Magnetic Lens For Plasma Engine

    NASA Technical Reports Server (NTRS)

    Sercel, Joel C.

    1992-01-01

    Low-field electromagnet coils placed downstream of plasma engine, polarized oppositely to higher-field but smaller radius coil in nozzle of engine, reduces divergence of plasma jet, thereby increasing efficiency of engine. Concept tested by computer simulation based on simplified mathematical model of plasma, engine, and coils.

  5. High-power radiating plasma

    NASA Technical Reports Server (NTRS)

    Rozanov, V. B.; Rukhadze, A. A.

    1984-01-01

    The physical principles underlying the use of radiating plasmas for the optical pumping of lasers are described. Particular consideration is given to the properties of radiating plasmas; radiation selectivity; the dynamics, equilibrium, and stability of radiating plasmas; the radiative Reynolds number; and experimental results on radiating discharges.

  6. Plasma Detachment Study in VASIMR

    Microsoft Academic Search

    A. V. Ilin; F. R. Chang Díaz; J. P. Squire; B. N. Breizman; S. V. Novakovski; R. Z. Sagdeev

    2000-01-01

    We present kinetic and MHD simulations of plasma detachment in the exhaust of the Variable Specific Impulse Magnetoplasma Rocket (VASIMR). The detachment is associated with a transition from subalfvenic to superalfvenic plasma flow in the magnetic nozzle. As a result, the kinetic energy of the outgoing plasma flow is greater than the magnetic field energy in the exhaust area, so

  7. Plasma chemistry and its applications

    NASA Technical Reports Server (NTRS)

    Hozumi, K.

    1980-01-01

    The relationship between discharge phenomena and plasma chemistry, as well as the equipment and mechanisms of plasma chemical reactions are described. Various areas in which plasma chemistry is applied are surveyed, such as: manufacturing of semiconductor integrated circuits; synthetic fibers; high polymer materials for medical uses; optical lenses; and membrane filters (reverse penetration films).

  8. Plasma Physics John F. Kennedy

    E-print Network

    Princeton Plasma Physics Laboratory

    v v v v v Princeton Plasma Physics Laboratory N 278 95 1 95 18 NEW YORK John F. Kennedy Int Campus/ Sayre Drive Sign PPPLSayre Dr. Location: Princeton Plasma Physics Laboratory James Forrestal Campus U.S. Route #1 North at Sayre Drive Plainsboro, NJ 08536 Mailing Address: Princeton Plasma Physics

  9. Laser Assisted Plasma Arc Welding

    Microsoft Academic Search

    PHILLIP W

    1999-01-01

    Experiments have been performed using a coaxial end-effecter to combine a focused laser beam and a plasma arc. The device employs a hollow tungsten electrode, a focusing lens, and conventional plasma arc torch nozzles to co-locate the focused beam and arc on the workpiece. Plasma arc nozzles were selected to protect the electrode from laser generated metal vapor. The project

  10. Plasma antioxidants from chocolate

    Microsoft Academic Search

    Mauro Serafini; Rossana Bugianesi; Giuseppe Maiani; Silvia Valtuena; Simone De Santis; Alan Crozier

    2003-01-01

    There is some speculation that dietary flavonoids from chocolate, in particular (-)epicatechin, may promote cardiovascular health as a result of direct antioxidant effects or through antithrombotic mechanisms. Here we show that consumption of plain, dark chocolate (Fig. 1) results in an increase in both the total antioxidant capacity and the (-)epicatechin content of blood plasma, but that these effects are

  11. Vacuum plasma spray coating

    NASA Technical Reports Server (NTRS)

    Holmes, Richard R.; Mckechnie, Timothy N.

    1989-01-01

    Currently, protective plasma spray coatings are applied to space shuttle main engine turbine blades of high-performance nickel alloys by an air plasma spray process. Originally, a ceramic coating of yttria-stabilized zirconia (ZrO2.12Y2O3) was applied for thermal protection, but was removed because of severe spalling. In vacuum plasma spray coating, plasma coatings of nickel-chromium-aluminum-yttrium (NiCrAlY) are applied in a reduced atmosphere of argon/helium. These enhanced coatings showed no spalling after 40 MSFC burner rig thermal shock cycles between 927 C (1700 F) and -253 C (-423 F), while current coatings spalled during 5 to 25 test cycles. Subsequently, a process was developed for applying a durable thermal barrier coating of ZrO2.8Y2O3 to the turbine blades of first-stage high-pressure fuel turbopumps utilizing the enhanced NiCrAlY bond-coating process. NiCrAlY bond coating is applied first, with ZrO2.8Y2O3 added sequentially in increasing amounts until a thermal barrier coating is obtained. The enchanced thermal barrier coating has successfully passed 40 burner rig thermal shock cycles.

  12. Plasma cell gingivitis.

    PubMed

    Joshi, Chandershekhar; Shukla, Pradeep

    2015-01-01

    The aim of the article is to present a report on the clinical presentation of plasma cell gingivitis with the use of herbal toothpowder. Plasma cell gingivitis [PCG] is a rare benign condition of the gingiva characterized by sharply demarcated erythematous and edematous gingivitis often extending to the mucogingival junction. As the name suggests it is diffuse and massive infiltration of plasma cells into the sub-epithelial gingival tissue. It is a hypersensitivity reaction to some antigen, often flavouring agents or spices found in chewing gums, toothpastes and lorenzes. A 27-yr old male with a chief complaint of painful, bleeding swollen mass in his lower front teeth region with prolong use of herbal toothpowder. The gingiva bled readily on probing. Patient was advised to refrain from the use of herbal toothpowder and along with periodontal treatment, no further reoccurrence was found. as more and more herbal products are gaining popularity, clinicians should be aware of effects of these products. Early diagnosis is essential as plasma cell gingivitis has similar pathologic changes seen clinically as in leukemia, HIV infection, discoid lupus erythematosis, atrophic lichen planus, desquamative gingivitis, or cicatrical pemphigoid which must be differentiated through hematologic and serologic testing. PMID:26015677

  13. Magnetospheric space plasma investigations

    NASA Technical Reports Server (NTRS)

    Comfort, Richard H.; Horwitz, James L.

    1993-01-01

    The topics addressed are: (1) generalized semikinetic models; (2) collision-collisionless transition model; (3) observation of O+ outflows; (4) equatorial transitions; (5) inner plasmasphere-ionosphere coupling; (6) plasma wave physical processes; (7) ULF wave ray-tracing; and (8) nighttime anomalous electron heating events.

  14. Implicit plasma simulation

    SciTech Connect

    Langdon, A.B.

    1985-03-03

    Implicit time integration methods have been used extensively in numerical modelling of slowly varying phenomena in systems that also support rapid variation. Examples include diffusion, hydrodynamics and reaction kinetics. This article discussed implementation of implicit time integration in plasma codes of the ''particle-in-cell'' family, and the benefits to be gained.

  15. Pulverized coal plasma gasification

    Microsoft Academic Search

    R. A. Kalinenko; A. P. Kuznetsov; A. A. Levitsky; V. E. Messerle; Yu. A. Mirokhin; L. S. Polak; Z. B. Sakipov; A. B. Ustimenko

    1993-01-01

    A number of experiments on the plasma-vapor gasification of brown coals of three types have been carried out using an experimental plant with an electric-arc reactor of the combined type. On the basis of the material and heat balances, process parameters have been obtained: the degree of carbon gasification (?c), the level of sulfur conversion into the gas phase (?s),

  16. Plasma based accelerators

    SciTech Connect

    Evans, R.G.

    1987-05-05

    A plasma medium can support a variety of wave motions which may be useful for accelerating charged particles. For highly relativistic beams the longitudinal electrostatic wave is most suitable and may be driven by laser or by particle beams. The basic principles, limitations and prospects for these devices are discussed.

  17. Solar thermal plasma chamber

    Microsoft Academic Search

    Joseph Bonometti; Donald R. Buchele; Charles H. Castle; Don A. Gregory

    2001-01-01

    A unique solar thermal chamber has been designed and fabricated to produce the maximum concentration of solar energy and highest temperature possible. Its primary purpose was for solar plasma propulsion experiments and related material specimen testing above 3000 Kelvin. The design not only maximized solar concentration, but also, minimized infrared heat loss. This paper provides the underlining theory and operation

  18. Plasma PhysicsPlasma Physics Atoms Beams and PlasmasAtoms Beams and Plasmas

    E-print Network

    Strathclyde, University of

    by EPSRC around and interact with each other but they still have a collective behaviour While rare on earth:- ross.bryson@strath.ac.uk Overview The aim of my research is to study the dynamics of an electron beam in National Geographic NASA The Earth Plasmas that occur naturally on earth include lightning, the auroras

  19. Plasma membrane microdomains

    Microsoft Academic Search

    Frederick R Maxfield

    2002-01-01

    Several lines of evidence indicate that the lipids in the plasma membrane of animal cells are inhomogeneously distributed, and that various types of specialized lipid domains play an important role in many biological processes. The characteristics of these domains, such as size, composition and dynamics, are currently under active investigation. It appears that there are many different types of membrane

  20. Dissipation in intercluster plasma

    E-print Network

    Maxim Lyutikov

    2007-09-11

    We discuss dissipative processes in strongly gyrotropic, nearly collisionless plasma in clusters of galaxies (ICM). First, we point out that Braginsky theory, which assumes that collisions are more frequent that the system's dynamical time scale, is inapplicable to fast, sub-viscous ICM motion. Most importantly, the electron contribution to collisional magneto-viscosity dominates over that of ions for short-scale Alfvenic motions. Thus, if a turbulent cascade develops in the ICM and propagates down to scales $\\leq 1$ kpc, it is damped collisionally not on ions, but on electrons. Second, in high beta plasma of ICM, small variations of the magnetic field strength, of relative value $\\sim 1/\\beta$, lead to development of anisotropic pressure instabilities (firehose, mirror and cyclotron). Unstable wave modes may provide additional resonant scattering of particles, effectively keeping the plasma in a state of marginal stability. We show that in this case the dissipation rate of a laminar, subsonic, incompressible flows scales as inverse of plasma beta parameter. We discuss application to the problem of ICM heating.

  1. Fundamentals of Plasma Physics

    Microsoft Academic Search

    P J Cargill

    2007-01-01

    The widespread importance of plasmas in many areas of contemporary physics makes good textbooks in the field that are both introductory and comprehensive invaluable. This new book by Paul Bellen from CalTech by and large meets these goals. It covers the traditional textbook topics such as particle orbits, the derivation of the MHD equations from Vlasov theory, cold and warm

  2. Plasma cell gingivitis

    PubMed Central

    Joshi, Chandershekhar; Shukla, Pradeep

    2015-01-01

    The aim of the article is to present a report on the clinical presentation of plasma cell gingivitis with the use of herbal toothpowder. Plasma cell gingivitis [PCG] is a rare benign condition of the gingiva characterized by sharply demarcated erythematous and edematous gingivitis often extending to the mucogingival junction. As the name suggests it is diffuse and massive infiltration of plasma cells into the sub-epithelial gingival tissue. It is a hypersensitivity reaction to some antigen, often flavouring agents or spices found in chewing gums, toothpastes and lorenzes. A 27-yr old male with a chief complaint of painful, bleeding swollen mass in his lower front teeth region with prolong use of herbal toothpowder. The gingiva bled readily on probing. Patient was advised to refrain from the use of herbal toothpowder and along with periodontal treatment, no further reoccurrence was found. as more and more herbal products are gaining popularity, clinicians should be aware of effects of these products. Early diagnosis is essential as plasma cell gingivitis has similar pathologic changes seen clinically as in leukemia, HIV infection, discoid lupus erythematosis, atrophic lichen planus, desquamative gingivitis, or cicatrical pemphigoid which must be differentiated through hematologic and serologic testing. PMID:26015677

  3. Flare Plasma Iron Abundance

    NASA Technical Reports Server (NTRS)

    Dennis, Brian R.; Dan, Chau; Jain, Rajmal; Schwartz, Richard A.; Tolbert, Anne K.

    2008-01-01

    The equivalent width of the iron-line complex at 6.7 keV seen in flare X-ray spectra suggests that the iron abundance of the hottest plasma at temperatures >approx.10 MK may sometimes be significantly lower than the nominal coronal abundance of four times the photospheric value that is commonly assumed. This conclusion is based on X-ray spectral observations of several flares seen in common with the Ramaty High Energy Solar Spectroscopic Imager (RHESSI) and the Solar X-ray Spectrometer (SOXS) on the second Indian geostationary satellite, GSAT-2. The implications of this will be discussed as it relates to the origin of the hot flare plasma - either plasma already in the corona that is directly heated during the flare energy release process or chromospheric plasma that is heated by flare-accelerated particles and driven up into the corona. Other possible explanations of lower-than-expected equivalent widths of the iron-line complex will also be discussed.

  4. Reacting plasma project at IPP Japan

    NASA Astrophysics Data System (ADS)

    Miyahara, A.; Momota, H.; Hamada, Y.; Kawamura, K.; Akimune, H.

    1981-01-01

    Contributed papers of a seminar on burning plasma are collected. An overview of the reacting plasma project in Japan is given and more specific topics concerning plasma and fusion physics are addressed including burning plasma and requirements for design, plasma heating and diagnostics, tritium problems in plasma experiments, and a D(-) ion source using Si-semiconductors.

  5. Merging and Splitting of Plasma Spheroids in a Dusty Plasma

    NASA Astrophysics Data System (ADS)

    Mikikian, Maxime; Tawidian, Hagop; Lecas, Thomas

    2012-12-01

    Dust particle growth in a plasma is a strongly disturbing phenomenon for the plasma equilibrium. It can induce many different types of low-frequency instabilities that can be experimentally observed, especially using high-speed imaging. A spectacular case has been observed in a krypton plasma where a huge density of dust particles is grown by material sputtering. The instability consists of well-defined regions of enhanced optical emission that emerge from the electrode vicinity and propagate towards the discharge center. These plasma spheroids have complex motions resulting from their mutual interaction that can also lead to the merging of two plasma spheroids into a single one. The reverse situation is also observed with the splitting of a plasma spheroid into two parts. These results are presented for the first time and reveal new behaviors in dusty plasmas.

  6. Merging and splitting of plasma spheroids in a dusty plasma.

    PubMed

    Mikikian, Maxime; Tawidian, Hagop; Lecas, Thomas

    2012-12-14

    Dust particle growth in a plasma is a strongly disturbing phenomenon for the plasma equilibrium. It can induce many different types of low-frequency instabilities that can be experimentally observed, especially using high-speed imaging. A spectacular case has been observed in a krypton plasma where a huge density of dust particles is grown by material sputtering. The instability consists of well-defined regions of enhanced optical emission that emerge from the electrode vicinity and propagate towards the discharge center. These plasma spheroids have complex motions resulting from their mutual interaction that can also lead to the merging of two plasma spheroids into a single one. The reverse situation is also observed with the splitting of a plasma spheroid into two parts. These results are presented for the first time and reveal new behaviors in dusty plasmas. PMID:23368337

  7. Pulsed Electromagnetic Acceleration of Plasmas

    NASA Technical Reports Server (NTRS)

    Thio, Y. C. Francis; Cassibry, Jason T.; Markusic, Tom E.; Rodgers, Stephen L. (Technical Monitor)

    2002-01-01

    A major shift in paradigm in driving pulsed plasma thruster is necessary if the original goal of accelerating a plasma sheet efficiently to high velocities as a plasma "slug" is to be realized. Firstly, the plasma interior needs to be highly collisional so that it can be dammed by the plasma edge layer not (upstream) adjacent to the driving 'vacuum' magnetic field. Secondly, the plasma edge layer needs to be strongly magnetized so that its Hall parameter is of the order of unity in this region to ensure excellent coupling of the Lorentz force to the plasma. Thirdly, to prevent and/or suppress the occurrence of secondary arcs or restrike behind the plasma, the region behind the plasma needs to be collisionless and extremely magnetized with sufficiently large Hall parameter. This places a vacuum requirement on the bore conditions prior to the shot. These requirements are quantified in the paper and lead to the introduction of three new design parameters corresponding to these three plasma requirements. The first parameter, labeled in the paper as gamma (sub 1), pertains to the permissible ratio of the diffusive excursion of the plasma during the course of the acceleration to the plasma longitudinal dimension. The second parameter is the required Hall parameter of the edge plasma region, and the third parameter the required Hall parameter of the region behind the plasma. Experimental research is required to quantify the values of these design parameters. Based upon fundamental theory of the transport processes in plasma, some theoretical guidance on the choice of these parameters are provided to help designing the necessary experiments to acquire these data.

  8. Plasma chemistry for inorganic materials

    NASA Technical Reports Server (NTRS)

    Matsumoto, O.

    1980-01-01

    Practical application of plasma chemistry to the development of inorganic materials using both low temperature and warm plasmas are summarized. Topics cover: the surface nitrification and oxidation of metals; chemical vapor deposition; formation of minute oxide particles; the composition of oxides from chloride vapor; the composition of carbides and nitrides; freezing high temperature phases by plasma arc welding and plasma jet; use of plasma in the development of a substitute for petroleum; the production of silicon for use in solar cell batteries; and insulating the inner surface of nuclear fusion reactor walls.

  9. Modulational interactions in quantum plasmas

    SciTech Connect

    Sayed, F.; Tyshetskiy, Yu. [School of Physics, University of Sydney, New South Wales 2006 (Australia)] [School of Physics, University of Sydney, New South Wales 2006 (Australia); Vladimirov, S. V. [School of Physics, University of Sydney, New South Wales 2006 (Australia) [School of Physics, University of Sydney, New South Wales 2006 (Australia); Faculty of Engineering, Yokohama National University, Yokohama 240-8501 (Japan); Metamaterials Laboratory, National Research University of Information Technology, Mechanics, and Optics, St. Petersburg 199034 (Russian Federation); Ishihara, O. [Faculty of Engineering, Yokohama National University, Yokohama 240-8501 (Japan)] [Faculty of Engineering, Yokohama National University, Yokohama 240-8501 (Japan)

    2013-07-15

    A formalism for treating modulational interactions of electrostatic fields in collisionless quantum plasmas is developed, based on the kinetic Wigner-Poisson model of quantum plasma. This formalism can be used in a range of problems of nonlinear interaction between electrostatic fields in a quantum plasma, such as development of turbulence, self-organization, as well as transition from the weak turbulent state to strong turbulence. In particular, using this formalism, we obtain the kinetic quantum Zakharov equations that describe nonlinear coupling of high frequency Langmuir waves to low frequency plasma density variations, for cases of non-degenerate and degenerate plasma electrons.

  10. On description of quantum plasma

    E-print Network

    S. V. Vladimirov; Yu. O. Tyshetskiy

    2011-01-21

    A plasma becomes quantum when the quantum nature of its particles significantly affects its macroscopic properties. To answer the question of when the collective quantum plasma effects are important, a proper description of such effects is necessary. We consider here the most common methods of description of quantum plasma, along with the related assumptions and applicability limits. In particular, we analyze in detail the hydrodynamic description of quantum plasma, as well as discuss some kinetic features of analytic properties of linear dielectric response function in quantum plasma. We point out the most important, in our view, fundamental problems occurring already in the linear approximation and requiring further investigation. (submitted to Physics-Uspekhi)

  11. Closed inductively coupled plasma cell

    DOEpatents

    Manning, T.J.; Palmer, B.A.; Hof, D.E.

    1990-11-06

    A closed inductively coupled plasma cell generates a relatively high power, low noise plasma for use in spectroscopic studies is disclosed. A variety of gases can be selected to form the plasma to minimize spectroscopic interference and to provide a electron density and temperature range for the sample to be analyzed. Grounded conductors are placed at the tube ends and axially displaced from the inductive coil, whereby the resulting electromagnetic field acts to elongate the plasma in the tube. Sample materials can be injected in the plasma to be excited for spectroscopy. 1 fig.

  12. Space plasma contractor research, 1988

    NASA Technical Reports Server (NTRS)

    Williams, John D.; Wilbur, Paul J.

    1989-01-01

    Results of experiments conducted on hollow cathode-based plasma contractors are reported. Specific tests in which attempts were made to vary plasma conditions in the simulated ionospheric plasma are described. Experimental results showing the effects of contractor flowrate and ion collecting surface size on contactor performance and contactor plasma plume geometry are presented. In addition to this work, one-dimensional solutions to spherical and cylindircal space-charge limited double-sheath problems are developed. A technique is proposed that can be used to apply these solutions to the problem of current flow through elongated double-sheaths that separate two cold plasmas. Two conference papers which describe the essential features of the plasma contacting process and present data that should facilitate calibration of comprehensive numerical models of the plasma contacting process are also included.

  13. Gravitational lensing in plasma: Relativistic images at homogeneous plasma

    E-print Network

    Oleg Yu. Tsupko; Gennady S. Bisnovatyi-Kogan

    2013-05-30

    We investigate the influence of plasma presence on relativistic images formed by Schwarzschild black hole lensing. When a gravitating body is surrounded by a plasma, the lensing angle depends on a frequency of the electromagnetic wave due to refraction properties, and the dispersion properties of the light propagation in gravitational field in plasma. The last effect leads to difference, even in uniform plasma, of gravitational deflection angle in plasma from vacuum case. This angle depends on the photon frequency, what resembles the properties of the refractive prism spectrometer. Here we consider the case of a strong deflection angle for the light, traveling near the Schwarzschild black hole, surrounded by a uniform plasma. Asymptotic formulae are obtained for the case of a very large deflection angle, exceeding $2\\pi$. We apply these formulae for calculation of position and magnification of relativistic images in a homogeneous plasma, which are formed by the photons performing one or several revolutions around the central object. We conclude that the presence of the uniform plasma increases the angular size of relativistic rings or the angular separation of point images from the gravitating center. The presence of the uniform plasma increases also a magnification of relativistic images. The angular separation and the magnification become significantly larger than in the vacuum case, when the photon frequency goes to a plasma frequency.

  14. Fresh-frozen plasma, pathogen-reduced single-donor plasma or bio-pharmaceutical plasma?

    PubMed

    Hellstern, Peter

    2008-08-01

    Three types of therapeutic plasma are available that differ in their manufacturing processes, composition, clinical efficacy, and side effects. Quarantine-stored, not pathogen-reduced fresh-frozen plasma (QFFP) is prepared from single whole blood or plasma donations. The manufacture of pathogen-reduced single-donor plasmas such as methylene blue-light treated (MLP) or amotosalen-ultraviolet light treated plasma (ALP) involves the addition of a chemical followed by irradiation and subsequent removal of the chemical. Both plasma types show substantial fluctuation of clotting factor and inhibitor levels according to interindividual variations, and both carry the risk of inducing transfusion-associated lung injury (TRALI). Photo-oxidation in pathogen-reduced single-donor plasmas reduces clottable fibrinogen and other clotting factors markedly, and there is a lack of clear evidence showing whether this is harmful or not. MLP also appears to be less effective clinically than QFFP. Like clotting factor or inhibitor concentrates, solvent/detergent-treated plasmas (SDP) are bio-pharmaceutical preparations derived from large plasma pools, and variations in plasma protein levels from batch-to-batch are for that reason low. The SD manufacturing process inevitably involves a considerable reduction of plasmin inhibitor (PI), and moderate reduction of all other clotting factors and inhibitors in the final plasma bags. Clinical studies and broad clinical use have however shown that this does not significantly reduce clinical efficacy or increase adverse events. SDPs obviously do not induce TRALI and the risk of allergic reactions is significantly lower than for QFFP. Common to all three plasma types is that the time between donation and freezing the plasma, and whether plasma from whole blood or apheresis plasma is used as starting material, are decisive determinants for the clotting factor and inhibitor potencies in the final bags. Plasma frozen 3-6h after donation, and apheresis plasma, contain markedly greater amounts of clotting factors and inhibitors than plasma frozen 15-24h after collection or plasma from whole blood. Lyophilisation and the pooling of single-donor plasma units with ABO blood group in suitable proportions (Uniplas) facilitate SDP handling and logistics without loss of clinical efficacy. SDP is obviously at least as cost-effective as QFFP if non-infectious adverse events including TRALI are taken into account, at least in younger patients and patients with good prognosis. PMID:18583192

  15. Plasma waves and instabilities

    NASA Astrophysics Data System (ADS)

    Gurnett, Donald A.

    An account is given of the waves and instabilities occurring at collisionless shocks, with attention to the mechanisms responsible for the generation of these waves. The transition region of the shock usually involves an abrupt broadband burst of electrostatic noise that extends from below the lower hybrid resonance to near the electron plasma frequency, and by a broadband burst of whistler mode EM noise below the electron cyclotron frequency. Electrostatic lower hybrid waves are also noted. Upstream of the shock, electron plasma oscillations, ion acoustic waves, and intense ULF MHD waves are often observed. The region downstream of the shock is usually very chaotic; electrostatic waves often extend long distances into the downstream region, together with whistler mode emissions.

  16. Potentials of fissioning plasmas

    NASA Technical Reports Server (NTRS)

    Thom, K.

    1979-01-01

    Successful experiments with the nuclear pumping of lasers have demonstrated that in a gaseous medium the kinetic energy of fission fragments can be converted directly into nonequilibrium optical radiation. This confirms the concept that the fissioning medium in a gas-phase nuclear reactor shows an internal structure such as a plasma in near thermal equilibrium varying up to a state of extreme nonequilibrium. During 20 years of research under NASA support major elements of the fissioning plasma reactor were demonstrated in theory and experiment, culminating in a proof-of-principle reactor test conducted at the Los Alamos Scientific Laboratory. It is concluded that the construction of a gaseous fuel reactor power plant is within the reach of present technology.

  17. Hybrid plasma modeling.

    SciTech Connect

    Hopkins, Matthew Morgan; DeChant, Lawrence Justin.; Piekos, Edward Stanley; Pointon, Timothy David

    2009-02-01

    This report summarizes the work completed during FY2007 and FY2008 for the LDRD project ''Hybrid Plasma Modeling''. The goal of this project was to develop hybrid methods to model plasmas across the non-continuum-to-continuum collisionality spectrum. The primary methodology to span these regimes was to couple a kinetic method (e.g., Particle-In-Cell) in the non-continuum regions to a continuum PDE-based method (e.g., finite differences) in continuum regions. The interface between the two would be adjusted dynamically ased on statistical sampling of the kinetic results. Although originally a three-year project, it became clear during the second year (FY2008) that there were not sufficient resources to complete the project and it was terminated mid-year.

  18. Plasma polymerization (review)

    SciTech Connect

    Vinogradov, G.K.

    1986-11-01

    The term ''plasma (gaseous discharge) polymerization'' is widely used to denote the process of forming high molecular weight products in electrical discharges. The purpose of the present review is primarily to analyze the state and methodology of research on gaseous discharge polymerization and to clarify the main approaches and trends in the literature. Experimental apparatus, internal plasma parameters, and research on the structure of polymer films and surface processes are discussed. IR spectroscopy and ESCA (electron spectroscopy for chemical analysis) as methods of studying the structure and composition of a polymer film are examined. The proposed models presented here are based primarily on the kinetic behavior of polymer film formation and on general considerations about the relation between the external parameters of discharges and the fluxes of various particle species onto the surface of a growing film which provide for the formation of the film.

  19. Plasma dust crystallization

    NASA Technical Reports Server (NTRS)

    Goree, John; Thomas, H.; Morfill, G.

    1994-01-01

    In a ground-based definition study, a concept for a new type of microgravity experiment is developed. We formed a new state of matter: a crystalline lattice structure of charged micron-size spheres, suspended in a charge-neutral plasma. The plasma is formed by a low-pressure radio-frequency argon discharge. Solid microspheres are introduced, and they gain a negative electric charge. They are cooled by molecular drag on the ambient neutral gas. They are detected by laser light scattering and video photography. Laboratory experiments have demonstrated that a two-dimensional nonquantum lattice forms through the Coulomb interaction of these spheres. Microgravity is thought to be required to observe a three-dimensional structure.

  20. Permanent magnet plasma lens

    NASA Astrophysics Data System (ADS)

    Goncharov, A.; Gorshkov, V.; Gubarev, S.; Dobrovolsky, A.; Protsenko, I.; Brown, I.

    2002-02-01

    We have designed and fabricated, for the first time, a simple, compact, and low-cost electrostatic plasma lens based on the use of permanent magnets rather than an electrically driven solenoid to establish the magnetic field. Characteristics of the focused ion beam passed through the lens have been measured. Some of the beam characteristics depend strongly on the applied magnetic field strength and the precise form of the external potential distribution applied along the lens electrodes. The experimental results obtained at the Institute of Physics (Kiev) and at the Lawrence Berkeley National Laboratory (Berkeley) show that this plasma optical device can be used beneficially for focusing and manipulating moderate energy, large area, heavy metal ion beams.

  1. Plasma wave accelerator. II

    SciTech Connect

    Mori, W.; Joshi, C.; Dawson, J.M.

    1982-01-01

    It was shown that the insertion of a cross magnetic field prevents the particles from getting out of phase with the electric field of the plasma wave in the beat wave accelerator scheme. Thus, using a CO/sub 2/ laser, n/sub c//n/sub e/ = (..omega../sub 0//..omega../sub p/)/sup 2/ approx. 35, and a 300 kG magnetic field, electrons can be (in principle) accelerated to 100 GeV in 2 meters. For comparison without the magnetic field, the same energies may be obtained in a n/sub c//n/sub e/ approx. 10/sup 5/ plasma over a distance of 100 meters.

  2. Plasma and magnetospheric research

    NASA Technical Reports Server (NTRS)

    Comfort, R. H.; Horwitz, J. L.

    1985-01-01

    Several programs and variations have been developed to determine statistical means of different plasma parameters when binned in different variables. These parameters include temperature, densities and spacecraft potentials for any of the ion species, as well as ratios of these variables for any other ion species to the corresponding variable for H(+). The variables for binning include L, radial distance, and geomagnetic latitude; and separate statistics are automatically run for local morning and local evening data. These programs all run from output files from the plasma parameter thin sheath analysis program. A variant program also bins for magnetic activity, using either Kp or Dst, which requires an additional magnetic activity input file. These programs can be run either interactively or in batch mode, using file listings generated by a DIRECTORY command. In addition to printed output, these programs generate output files which can be used to plot the results. Programs to plot these averaged data are under development.

  3. Nature of the Solar Wind Electron Distribution Functions in the Slow and Fast Solar Wind at 1 AU

    Microsoft Academic Search

    C. Salem; D. Hubert; S. Bale; D. Larson; B. Lin

    2004-01-01

    The non equilibrium characteristics of the solar wind electron distribution functions (EDF) at 1 AU are of great importance in many aspects, for instance in understanding heat conduction, plasma microinstabilities and transport in weakly collisional plasma, as well as in the scenario at the origin of the solar wind. It has been known for a long time that, in the

  4. Spectroscopy of divertor plasmas

    SciTech Connect

    Isler, R.C.

    1995-12-31

    The requirements for divertor spectroscopy are treated with respect to instrumentation and observations on present machines. Emphasis is placed on quantitative measurements.of impurity concentrations from the interpretation of spectral line intensities. The possible influence of non-Maxwellian electron distributions on spectral line excitation in the divertor is discussed. Finally the use of spectroscopy for determining plasma temperature, density, and flows is examined.

  5. Plasma Membrane Phospholipid Asymmetry

    Microsoft Academic Search

    Peter J. Quinn

    The maintenance of an asymmetric distribution of phospholipids across the plasma membrane with choline phospholipids predominating\\u000a on the external surface and amino phospholipids confined to the cytoplasmic leaflet of the membrane has now been well established.\\u000a The participation of aminophospholipid translocases in this process has been clearly demonstrated and the translocases themselves\\u000a have been characterized.\\u000a \\u000a One of the more significant

  6. Future of plasma simulation

    SciTech Connect

    Forslund, D.W.

    1986-01-01

    The author briefly comments on factors essential to improving the capabilities of plasma modeling. These factors include high input/output performance, large solid state disk capacity, symbolic debugging tools, high speed graphics, high speed image generation and workstations for pre- and post-processing. Also important is the development of additional software to provide an enhanced interface between the work-stations and supercomputers. (DWL)

  7. Platelet-rich plasma

    Microsoft Academic Search

    Robert E Marx; Eric R Carlson; Ralph M Eichstaedt; Steven R Schimmele; James E Strauss; Karen R Georgeff

    1998-01-01

    Platelet-rich plasma is an autologous source of platelet-derived growth factor and transforming growth factor beta that is obtained by sequestering and concentrating platelets by gradient density centrifugation. This technique produced a concentration of human platelets of 338% and identified platelet-derived growth factor and transforming growth factor beta within them. Monoclonal antibody assessment of cancellous cellular marrow grafts demonstrated cells that

  8. Electrons, Ions and Plasmas

    NSDL National Science Digital Library

    Mendez, J.

    This series of web pages provides information on a range of topics regarding charged particles. Starting with the properties of atomic electrons, this material describes the Edison and photoelectric effects, the interaction between charged particles and magnetic fields, and the creation of plasmas and positive ions. Other topics, including the history of research on charges, are covered in linked pages. This is part of a series of non-mathematical, linked explorations of the Earth's Magnetosphere.

  9. Wave and Plasma Simulations

    NASA Astrophysics Data System (ADS)

    Lazos, J.; Vasquez, B. J.

    2004-12-01

    Rapidly moving streams of plasma emanate from the Sun and team with long magnetized waves which are called Alfven waves. The waves have sharp edges showing evidence of nonlinear wave steepening. They are also arc-polarized wherein the total magnetic intensity is a constant but the magnetic field direction sweeps back and forth along a circular arc like a wiper-blade. The solar-wind plasma is nearly collisionless and shows evidence of preferred ion heating. There are also distinct beams of various atoms which stream relative to the main component of solar-wind protons. The detailed individual motions of the ions are important to follow in order to understand the behavior of the plasma and waves. We employ hybrid numerical simulations using particle ions and fluid electrons. We present results from 3 simulation projects which will demonstrate how small but resonant forces can cumulatively lead to large changes: (1) Small amplitude and linearly polarized Alfven waves propagating parallel to the background magnetic field nonlinearly steepen. We have measured the time of steepening as a function of the ratio of plasma to magnetic pressure, especially for ratios of order unity where analytical calculations cannot determine the steepening time. (2) Arc-polarized Alfven waves can propagate without changing form, but we show that small disturbances can lead to their decay into new waves. (3) Beams of ions streaming relative to one another can drive up waves from the smallest starting disturbances. We show that this slows the relative streaming speed below a threshold where the speed becomes steady. This work was completed at the University of New Hampshire through the Science and Mathematics Achievement through Research Training (SMART) program.

  10. Plasma Sensor Suite

    NASA Astrophysics Data System (ADS)

    Matlis, Eric; Bowles, Patrick; Corke, Thomas

    2008-11-01

    Progress has been made towards the development of a new class of sensors which have the potential to overcome the temperature limitations found in conventional sensors, thus addressing an important measurement challenge faced in the measurement of high speed flows. The new approach is based on the a.c.-driven mass-flow laboratory plasma anemometer developed by Matlis et al. and uses a weakly ionized glow discharge encapsulated between two electrodes as the sensing element. These sensors will feature proven elements of the technology used in the plasma anemometer, but will be extended for high-temperature, multiparameter operation. The sensitivity to different parameters can be provided by the design and orientation of the electrodes. The objective is to replace conventional sensors which provide diagnostics in the laboratory but are known to fail in real-world applications with a suite of rugged sensors optimized to measure wall shear-stress, pressure, temperature, heat flux, mass-flow, strain, and gas species. The advantages of the plasma sensor are that it has no mechanical parts (like a pressure transducer diaphragm) to fatigue or break, its operation is insensitive to temperature, it has a very high frequency response (2MHz +), and its output can be received wirelessly. These advantages over other sensors makes it ideal for use in high speed flows.

  11. PLASMA CELL LEUKEMIA

    PubMed Central

    de Larrea, Carlos Fernandez; Kyle, Robert A.; Durie, Brian GM; Ludwig, Heinz; Usmani, Saad; Vesole, David H.; Hajek, Roman; Miguel, Jésus San; Sezer, Orhan; Sonneveld, Pieter; Kumar, Shaji K.; Mahindra, Anuj; Comenzo, Ray; Palumbo, Antonio; Mazumber, Amitabha; Anderson, Kenneth C.; Richardson, Paul G.; Badros, Ashraf Z.; Caers, Jo; Cavo, Michele; LeLeu, Xavier; Dimopoulos, Meletios A.; Chim, CS; Schots, Rik; Noeul, Amara; Fantl, Dorotea; Mellqvist, Ulf-Henrik; Landgren, Ola; Chanan-Khan, Asher; Moreau, Philippe; Fonseca, Rafael; Merlini, Giampaolo; Lahuerta, JJ; Bladé, Joan; Orlowski, Robert Z.; Shah, Jatin J.

    2014-01-01

    Plasma cell leukemia (PCL) is a rare and aggressive variant of myeloma characterized by the presence of circulating plasma cells. It is classified as either primary PCL occurring at diagnosis or as secondary PCL in patients with relapsed/refractory myeloma. Primary PCL is a distinct clinic-pathologic entity with different cytogenetic and molecular findings. The clinical course is aggressive with short remissions and survival duration. The diagnosis is based upon the percentage (? 20%) and absolute number (? 2 × 10 9/L) of plasma cells in the peripheral blood. It is proposed that the thresholds for diagnosis be reexamined and consensus recommendations are made for diagnosis, as well as, response and progression criteria. Induction therapy needs to begin promptly and have high clinical activity leading to rapid disease control in an effort to minimize the risk of early death. Intensive chemotherapy regimens and bortezomib-based regimens are recommended followed by high-dose therapy with autologous stem-cell transplantation (HDT/ASCT) if feasible. Allogeneic transplantation can be considered in younger patients. Prospective multicenter studies are required to provide revised definitions and better understanding of the pathogenesis of PCL. PMID:23288300

  12. Nanomaterials induced plasma spectroscopy

    NASA Astrophysics Data System (ADS)

    El Sherbini, A. M.; Abdel Galil, A.; Allam, S. H.; El Sherbini, Th M.

    2014-11-01

    LIBS of nanosecond pulsed Nd: YAG laser (1064 nm) produced plasma from a set of nanomaterial and bulk targets (ZnO, Fe3O4, Ag2O, TiO2, SiO2 and Al2O3) is investigated at laser fluencies in the range 86 J/cm2 to 2.5 J/cm2. The optical emission spectra is recorded at the gate and time delay of 1 ps after the onset of the plasma in air having a constant spot size of 0.9 mm. Nanoparticle targets revealed salient enhanced spectral emission compared to their bulky counterparts. Atomic spectral lines average and integral radiance tend to decrease exponentially with laser fluence. Yet, plasma parameters measurements indicated unnoticeable variation of relative electron density and temperature. Therefore, self-absorption corrected enhanced spectral emission was plausibly attributed solely to variation in the inherent nanoparticle relative concentrations. Viable explanations were elaborated based on changes in the intrinsic physical properties of the nanomaterial under high power laser irradiation.

  13. Plasma immersion surface modification with metal ion plasma

    SciTech Connect

    Brown, I.G.; Yu, K.M. (Lawrence Berkeley Lab., CA (USA)); Godechot, X. (Lawrence Berkeley Lab., CA (USA) Societe Anonyme d'Etudes et Realisations Nucleaires (SODERN), 94 - Limeil-Brevannes (France))

    1991-04-01

    We describe here a novel technique for surface modification in which metal plasma is employed and by which various blends of plasma deposition and ion implantation can be obtained. The new technique is a variation of the plasma immersion technique described by Conrad and co-workers. When a substrate is immersed in a metal plasma, the plasma that condenses on the substrate remains there as a film, and when the substrate is then implanted, qualitatively different processes can follow, including' conventional' high energy ion implantation, recoil implantation, ion beam mixing, ion beam assisted deposition, and metallic thin film and multilayer fabrication with or without species mixing. Multiple metal plasma guns can be used with different metal ion species, films can be bonded to the substrate through ion beam mixing at the interface, and multilayer structures can be tailored with graded or abrupt interfaces. We have fabricated several different kinds of modified surface layers in this way. 22 refs., 4 figs.

  14. Plasma generating apparatus for large area plasma processing

    DOEpatents

    Tsai, C.C.; Gorbatkin, S.M.; Berry, L.A.

    1991-07-16

    A plasma generating apparatus for plasma processing applications is based on a permanent magnet line-cusp plasma confinement chamber coupled to a compact single-coil microwave waveguide launcher. The device creates an electron cyclotron resonance (ECR) plasma in the launcher and a second ECR plasma is created in the line cusps due to a 0.0875 tesla magnetic field in that region. Additional special magnetic field configuring reduces the magnetic field at the substrate to below 0.001 tesla. The resulting plasma source is capable of producing large-area (20-cm diam), highly uniform (.+-.5%) ion beams with current densities above 5 mA/cm[sup 2]. The source has been used to etch photoresist on 5-inch diam silicon wafers with good uniformity. 3 figures.

  15. Plasma generating apparatus for large area plasma processing

    DOEpatents

    Tsai, Chin-Chi (Oak Ridge, TN); Gorbatkin, Steven M. (Oak Ridge, TN); Berry, Lee A. (Oak Ridge, TN)

    1991-01-01

    A plasma generating apparatus for plasma processing applications is based on a permanent magnet line-cusp plasma confinement chamber coupled to a compact single-coil microwave waveguide launcher. The device creates an electron cyclotron resonance (ECR) plasma in the launcher and a second ECR plasma is created in the line cusps due to a 0.0875 tesla magnetic field in that region. Additional special magnetic field configuring reduces the magnetic field at the substrate to below 0.001 tesla. The resulting plasma source is capable of producing large-area (20-cm diam), highly uniform (.+-.5%) ion beams with current densities above 5 mA/cm.sup.2. The source has been used to etch photoresist on 5-inch diam silicon wafers with good uniformity.

  16. Rydberg atoms in ultracold plasmas

    NASA Astrophysics Data System (ADS)

    Rolston, Steven

    2009-05-01

    Ultracold plasmas are formed through the photoionization of laser-cooled atoms, or spontaneous ionization of a dense cloud of Rydberg atoms or now molecules[1]. Ultracold plasmas are inherently metastable, as the ions and electrons would be in a lower energy state bound together as atoms. The dominant process of atom formation in these plasmas is three-body recombination, a collision between two electrons and an ion that leads to the formation of a Rydberg atom. This collisional process is not only important in determining the lifetime and density of the plasma, but is also critical in determining the time evolution of the temperature. The formation of the Rydberg atoms is accompanied by an increase in electron energy for the extra electron in the collision, and is a source of heating in these plasmas. Classical three-body recombination theory scales as T-9/2, and thus as a plasma cools due to a process such as adiabatic expansion, recombination-induced heating turns on, limiting the temperature [2]. The Rydberg atoms formed live in the plasma and contribute to the temperature dynamics, as collisions with plasma electrons can change the principal quantum number of the Rydberg atom, driving it to more tightly bound states (a source of plasma heating) or to higher states (a source of plasma cooling). If the plasma is cold and dense enough to be strongly coupled, classical three-body recombination theory breaks down. Recent theoretical work [3] suggests that the rate limits as the plasma gets strongly coupled. I will review the role of Rydberg atoms in ultracold plasmas and prospects for probing Rydberg collisions in the strongly coupled environment. [4pt] [1] J. P. Morrison, et al., Phys. Rev. Lett. 101, 205005 (2008 [0pt] [2] R. S. Fletcher, X. Zhang, and S. L. Rolston, Phys. Rev. Lett. 99, 145001 (2007 [0pt] [3] T. Pohl, private communication.

  17. Plasma-maser Instability in Magnetized Dusty Plasma

    Microsoft Academic Search

    Bipul J. Saikia; Mitsuhiro Nambu

    1999-01-01

    The plasma-maser theory of Langmuir waves in presence of low frequency dust-ion acoustic oscillations in a magnetized dusty plasma is presented. The up-conversion of wave energy in a dusty plasma is much enhanced owing to the increased acceleration of electrons by the dust-ion acoustic mode. The results have potential importance in interpretation of high frequency radiation in space and astrophysical

  18. The relation between plasma cysteine, plasma homocysteine and coronary atherosclerosis

    Microsoft Academic Search

    Winette E. van den Brandhof; Karin Haks; Evert G. Schouten; Petra Verhoef

    2001-01-01

    Several studies have reported that elevated plasma levels of total homocysteine (tHcy) are related to an increased risk of cardiovascular disease. Only a few studies have looked at the effect of cysteine, another amino thiol, on cardiovascular disease risk. Therefore, in the present case–control study we compared plasma total cysteine (tCys) levels and plasma tHcy levels among subjects with severe

  19. A contoured gap coaxial plasma gun with injected plasma armature

    NASA Astrophysics Data System (ADS)

    Witherspoon, F. Douglas; Case, Andrew; Messer, Sarah J.; Bomgardner, Richard; Phillips, Michael W.; Brockington, Samuel; Elton, Raymond

    2009-08-01

    A new coaxial plasma gun is described. The long term objective is to accelerate 100-200 ?g of plasma with density above 1017 cm-3 to greater than 200 km/s with a Mach number above 10. Such high velocity dense plasma jets have a number of potential fusion applications, including plasma refueling, magnetized target fusion, injection of angular momentum into centrifugally confined mirrors, high energy density plasmas, and others. The approach uses symmetric injection of high density plasma into a coaxial electromagnetic accelerator having an annular gap geometry tailored to prevent formation of the blow-by instability. The injected plasma is generated by numerous (currently 32) radially oriented capillary discharges arranged uniformly around the circumference of the angled annular injection region of the accelerator. Magnetohydrodynamic modeling identified electrode profiles that can achieve the desired plasma jet parameters. The experimental hardware is described along with initial experimental results in which approximately 200 ?g has been accelerated to 100 km/s in a half-scale prototype gun. Initial observations of 64 merging injector jets in a planar cylindrical testing array are presented. Density and velocity are presently limited by available peak current and injection sources. Steps to increase both the drive current and the injected plasma mass are described for next generation experiments.

  20. A contoured gap coaxial plasma gun with injected plasma armature.

    PubMed

    Witherspoon, F Douglas; Case, Andrew; Messer, Sarah J; Bomgardner, Richard; Phillips, Michael W; Brockington, Samuel; Elton, Raymond

    2009-08-01

    A new coaxial plasma gun is described. The long term objective is to accelerate 100-200 microg of plasma with density above 10(17) cm(-3) to greater than 200 km/s with a Mach number above 10. Such high velocity dense plasma jets have a number of potential fusion applications, including plasma refueling, magnetized target fusion, injection of angular momentum into centrifugally confined mirrors, high energy density plasmas, and others. The approach uses symmetric injection of high density plasma into a coaxial electromagnetic accelerator having an annular gap geometry tailored to prevent formation of the blow-by instability. The injected plasma is generated by numerous (currently 32) radially oriented capillary discharges arranged uniformly around the circumference of the angled annular injection region of the accelerator. Magnetohydrodynamic modeling identified electrode profiles that can achieve the desired plasma jet parameters. The experimental hardware is described along with initial experimental results in which approximately 200 microg has been accelerated to 100 km/s in a half-scale prototype gun. Initial observations of 64 merging injector jets in a planar cylindrical testing array are presented. Density and velocity are presently limited by available peak current and injection sources. Steps to increase both the drive current and the injected plasma mass are described for next generation experiments. PMID:19725654

  1. A contoured gap coaxial plasma gun with injected plasma armature

    SciTech Connect

    Witherspoon, F. Douglas; Case, Andrew; Messer, Sarah J.; Bomgardner, Richard II; Phillips, Michael W.; Brockington, Samuel; Elton, Raymond [HyperV Technologies Corp., Chantilly, Virginia 20151 (United States)

    2009-08-15

    A new coaxial plasma gun is described. The long term objective is to accelerate 100-200 {mu}g of plasma with density above 10{sup 17} cm{sup -3} to greater than 200 km/s with a Mach number above 10. Such high velocity dense plasma jets have a number of potential fusion applications, including plasma refueling, magnetized target fusion, injection of angular momentum into centrifugally confined mirrors, high energy density plasmas, and others. The approach uses symmetric injection of high density plasma into a coaxial electromagnetic accelerator having an annular gap geometry tailored to prevent formation of the blow-by instability. The injected plasma is generated by numerous (currently 32) radially oriented capillary discharges arranged uniformly around the circumference of the angled annular injection region of the accelerator. Magnetohydrodynamic modeling identified electrode profiles that can achieve the desired plasma jet parameters. The experimental hardware is described along with initial experimental results in which approximately 200 {mu}g has been accelerated to 100 km/s in a half-scale prototype gun. Initial observations of 64 merging injector jets in a planar cylindrical testing array are presented. Density and velocity are presently limited by available peak current and injection sources. Steps to increase both the drive current and the injected plasma mass are described for next generation experiments.

  2. Plasma Chemistry and Plasma Processing, Vol. 12, No.4, 1992 Infrared Radiation from an Arc Plasma and Its

    E-print Network

    Eagar, Thomas W.

    B ) Plasma Chemistry and Plasma Processing, Vol. 12, No.4, 1992 Infrared Radiation from an Arc Plasma and Its Application to Plasma Diagnostics Takayoshi Ohji1 and Thomas W. Eagar Received May 16 ifinfraredradiation from an arc plasma can fie used for diagnostic purposes. Tire properties of IR radiation

  3. Plasma Chemistry and Plasma Processing, Vol. 23, No. 1, March 2003 ( 2003) Model of the Negative DC Corona Plasma

    E-print Network

    Chen, Junhong

    Plasma Chemistry and Plasma Processing, Vol. 23, No. 1, March 2003 ( 2003) Model of the Negative DC Corona Plasma: Comparison to the Positive DC Corona Plasma Junhong Chen1 and Jane H. Davidson1,2 Receiûed March 26, 2002, reûised June 14, 2002 A numerical model of the negatiûe DC corona plasma along a thin

  4. Stages of Plasma Cell Neoplasms (Including Multiple Myeloma)

    MedlinePLUS

    ... Treatment Health Professional Plasma Cell Neoplasms Treatment Research Plasma Cell Neoplasms (Including Multiple Myeloma) Treatment (PDQ®) General Information About Plasma Cell Neoplasms Key Points Plasma cell neoplasms are ...

  5. Couette Flow of Unmagnetized Plasma

    E-print Network

    Collins, C; Cooper, C M; Flanagan, K; Khalzov, I V; Nornberg, M D; Seidlitz, B; Wallace, J; Forest, C B

    2014-01-01

    Differentially rotating flows of unmagnetized, highly conducting plasmas have been created in the Plasma Couette Experiment. Previously, hot-cathodes have been used to control plasma rotation by a stirring technique [C. Collins et al., Phys. Rev. Lett. 108, 115001(2012)] on the outer cylindrical boundary---these plasmas were nearly rigid rotors, modified only by the presence of a neutral particle drag. Experiments have now been extended to include stirring from an inner boundary, allowing for generalized Couette flow and opening a path for both hydrodynamic and magnetohydrodynamic experiments, as well as fundamental studies of plasma viscosity. Plasma is confined in a cylindrical, axisymmetric, multicusp magnetic field, with $T_eplasmas. We present measurements of a self-consistent, rotation-induced, species-dependent rad...

  6. Plasma ignition for laser propulsion

    NASA Technical Reports Server (NTRS)

    Askew, R. F.

    1982-01-01

    For a specific optical system a pulsed carbon dioxide laser having an energy output of up to 15 joules was used to initiate a plasma in air at one atmosphere pressure. The spatial and temporal development of the plasma were measured using a multiframe image converter camera. In addition the time dependent velocity of the laser supported plasma front which moves opposite to the direction of the laser pulse was measured in order to characterize the type of wavefront developed. Reliable and reproducible spark initiation was achieved. The lifetime of the highly dense plasma at the initial focal spot was determined to be less than 100 nanoseconds. The plasma front propagates toward the laser at a variable speed ranging from zero to 1.6 x 1,000,000 m/sec. The plasma front propagates for a total distance of approximately five centimeters for the energy and laser pulse shape employed.

  7. Adverse Effects of Plasma Transfusion

    PubMed Central

    Pandey, Suchitra; Vyas, Girish N.

    2012-01-01

    Plasma utilization has increased over the last two decades, and there is a growing concern that many plasma transfusions are inappropriate. Plasma transfusion is not without risk, and certain complications are more likely with plasma than other blood components. Clinical and laboratory investigations of the patients suffering reactions following infusion of fresh frozen plasma (FFP) define the etiology and pathogenesis of the panoply of adverse effects. We review here the pathogenesis, diagnosis, and management of the risks associated with plasma transfusion. Risks commonly associated with FFP include: (1) transfusion related acute lung injury; (2) transfusion associated circulatory overload, and (3) allergic/anaphylactic reactions. Other less common risks include (1) transmission of infections, (2) febrile non-hemolytic transfusion reactions, (3) RBC allo-immunization, and (4) hemolytic transfusion reactions. The affect of pathogen inactivation/reduction methods on these risks are also discussed. Fortunately, a majority of the adverse effects are not lethal and are adequately treated in clinical practice. PMID:22578374

  8. Space plasma branch at NRL

    NASA Astrophysics Data System (ADS)

    The Naval Research Laboratory (Washington, D.C.) formed the Space Plasma Branch within its Plasma Physics Division on July 1. Vithal Patel, former Program Director of Magnetospheric Physics, National Science Foundation, also joined NRL on the same date as Associate Superintendent of the Plasma Physics Division. Barret Ripin is head of the newly organized branch. The Space Plasma branch will do basic and applied space plasma research using a multidisciplinary approach. It consolidates traditional rocket and satellite space experiments, space plasma theory and computation, with laboratory space-related experiments. About 40 research scientists, postdoctoral fellows, engineers, and technicians are divided among its five sections. The Theory and Computation sections are led by Joseph Huba and Joel Fedder, the Space Experiments section is led by Paul Rodriguez, and the Pharos Laser Facility and Laser Experiments sections are headed by Charles Manka and Jacob Grun.

  9. The Plasma Liner Compression Experiment

    NASA Astrophysics Data System (ADS)

    Votroubek, George; Slough, John

    2010-12-01

    Magnetic fusion at high energy density requires compression of a magnetized target in a manner that can be repetitively performed. One approach being investigated in these experiments is the radial compression of a FRC target by a cylindrical plasma liner. A circular array consisting of 16 small coaxial plasma sources were placed at each end of a quartz chamber radially near the wall to form the plasma liner. Liner masses of 3 mg have been formed in Xenon and have been accelerated to a velocity of 50 km/s. An FRC was produced in an adjacent chamber and translated inside the plasma liner where theta-pinch coils were employed to drive the plasma liner radially inward compressing the FRC. Close agreement is found between experimental results and 2D MHD numerical calculations. Efficient coupling (~50%) between the compression bank and the plasma liner has been observed.

  10. Whistler wave driven plasma thruster

    SciTech Connect

    Bickford Hooper, E.; Stallard, B.W.; Makowski, M.A. (Lawrence Livermore National Laboratory L-637, P.O. Box 808 Livermore, CA 94550-9900 (United States))

    1993-01-20

    High density plasma can be generated by electron cyclotron resonance heating (ECRH) using whistler waves at densities for which the plasma frequency is much higher than the cyclotron frequency. This will result in a thruster operating at specific impulses of 10[sup 3]--10[sup 4] s and much higher power and thrust densities than usual for ECRH devices. As the plasma generation is by electromagnetic waves, there are no electrodes, and wall material problems are greatly eased, permitting reliable, long lifetime operation. We report on the modeling of such a thruster, including plasma flow as well as losses to an end wall and ionization. A helical antenna to couple the waves into the plasma column is analyzed, including effects of the anisotropic plasma dielectric constant. An initial experiment to test the concept is planned.

  11. Characterizing plasma mirrors near breakdown.

    PubMed

    Geissel, Matthias; Schollmeier, Marius S; Kimmel, Mark W; Rambo, Patrick K; Schwarz, Jens; Atherton, Briggs W; Brambrink, Erik

    2011-05-01

    Experiments dedicated to the characterization of plasma mirrors with a high energy, single shot short-pulse laser were performed at the 100 TW target area of the Z-Backlighter Facility at Sandia National Laboratories. A suite of beam diagnostics was used to characterize a high energy laser pulse with a large aperture through focus imaging setup. By varying the fluence on the plasma mirror around the plasma ignition threshold, critical performance parameters were determined and a more detailed understanding of the way in which a plasma mirror works could be deduced. It was found, that very subtle variations in the laser near field profile will have strong effects on the reflected pulse if the maximum fluence on the plasma mirror approaches the plasma ignition threshold. PMID:21639486

  12. Slotted antenna waveguide plasma source

    NASA Technical Reports Server (NTRS)

    Foster, John (Inventor)

    2007-01-01

    A high density plasma generated by microwave injection using a windowless electrodeless rectangular slotted antenna waveguide plasma source has been demonstrated. Plasma probe measurements indicate that the source could be applicable for low power ion thruster applications, ion implantation, and related applications. This slotted antenna plasma source invention operates on the principle of electron cyclotron resonance (ECR). It employs no window and it is completely electrodeless and therefore its operation lifetime is long, being limited only by either the microwave generator itself or charged particle extraction grids if used. The high density plasma source can also be used to extract an electron beam that can be used as a plasma cathode neutralizer for ion source beam neutralization applications.

  13. SSX MHD plasma wind tunnel

    NASA Astrophysics Data System (ADS)

    Brown, Michael R.; Schaffner, David A.

    2015-06-01

    A new turbulent plasma source at the Swarthmore Spheromak Experiment (SSX) facility is described. The MHD wind tunnel configuration employs a magnetized plasma gun to inject high-beta plasma into a large, well-instrumented, vacuum drift region. This provides unique laboratory conditions approaching that in the solar wind: there is no applied background magnetic field in the drift region and has no net axial magnetic flux; the plasma flow speed is on the order of the local sound speed (M ~ 1), so flow energy density is comparable to thermal energy density; and the ratio of thermal to magnetic pressure is of order unity (plasma ? ~ 1) so thermal energy density is also comparable to magnetic energy density. Results presented here and referenced within demonstrate the new capabilities and show how the new platform is proving useful for fundamental plasma turbulence studies.

  14. Resonance microwave volume plasma source

    SciTech Connect

    Berezhetskaya, N. K.; Kop'ev, V. A.; Kossyi, I. A.; Malykh, N. I.; Misakyan, M. A.; Taktakishvili, M. I.; Temchin, S. M. [Russian Academy of Sciences, Prokhorov Institute of General Physics (Russian Federation); Lee, Young Dong [Samsung Advanced Institute of Technology (Korea, Republic of)

    2007-07-15

    A conceptual design of a microwave gas-discharge plasma source is described. The possibility is considered of creating conditions under which microwave energy in the plasma resonance region would be efficiently converted into the energy of thermal and accelerated (fast) electrons. Results are presented from interferometric and probe measurements of the plasma density in a coaxial microwave plasmatron, as well as the data from probe measurements of the plasma potential and electron temperature. The dynamics of plasma radiation was recorded using a streak camera and a collimated photomultiplier. The experimental results indicate that, at relatively low pressures of the working gas, the nonlinear interaction between the microwave field and the inhomogeneous plasma in the resonance region of the plasmatron substantially affects the parameters of the ionized gas in the reactor volume.

  15. The plasma environment of comets

    SciTech Connect

    Gombosi, T.I. (USAF, Geophysics Laboratory, Hanscom AFB, MA (United States))

    1991-01-01

    U.S. research activities in the area of cometary plasma physics during 1987-1990 are reviewed. Consideration is given to mass loading and its consequences in the upstream region, the cometary shock, the cometosheath, the diamagnetic cavity boundary and the inner shock, and the plasma tail. Special attention is given to models and observations that have modified the pre-encounter understanding of cometary plasma environments. 211 refs.

  16. Purification of tantalum by plasma arc melting

    DOEpatents

    Dunn, Paul S. (Santa Fe, NM); Korzekwa, Deniece R. (Los Alamos, NM)

    1999-01-01

    Purification of tantalum by plasma arc melting. The level of oxygen and carbon impurities in tantalum was reduced by plasma arc melting the tantalum using a flowing plasma gas generated from a gas mixture of helium and hydrogen. The flowing plasma gases of the present invention were found to be superior to other known flowing plasma gases used for this purpose.

  17. REVIEWS OF TOPICAL PROBLEMS: Dusty plasmas

    Microsoft Academic Search

    Vladimir E. Fortov; Aleksei G. Khrapak; Sergei A. Khrapak; Vladimir I. Molotkov; Oleg F. Petrov

    2004-01-01

    The properties of dusty plasmas --- low-temperature plasmas containing charged macroparticles --- are considered. The most important elementary processes in dusty plasmas and the forces acting on dust particles are investigated. The results of experimental and theoretical investigations of different states of strongly nonideal dusty plasmas --- crystal-like, liquid-like, gas-like --- are summarized. Waves and oscillations in dusty plasmas, as

  18. Physics of Dusty Plasmas: Seventh Workshop. Proceedings

    Microsoft Academic Search

    M. Horanyi; S. Robertson; B. Walch

    1998-01-01

    These proceedings represent papers presented at the Seventh Workshop on the Physics of Dusty Plasmas, held in Boulder, Colorado in April, 1998. Dusty Plasmas are multicomponent plasmas where, in addition to electrons and ions, microscopic charge carriers are present. Dusty plasmas is perhaps the fastest growing area of plasma physics. The papers presented at the Workshop included, among others, the

  19. Plasma, The Fourth State of Matter

    ERIC Educational Resources Information Center

    Zandy, Hassan F.

    1970-01-01

    Discusses plasma as a source of energy through nuclear fission processes, as well as the difficulties encountered in such a process. States that 99 percent of the matter in the universe is plasma, and only 1 percent is the common three states of matter. Describes the fundamental properties of plasma, plasma "pinch, and plasma oscillations. (RR)

  20. Analysis of Microwave Propagation In Plasma

    E-print Network

    Anlage, Steven

    Analysis of Microwave Propagation In Plasma Elaine Chung Advisor: Dr. John Rodgers #12;Plasma OverviewPlasma Overview · Plasma ­ ionized gas htt[p://www.noaa.gov http://www.photoeverywhere.co.uk http://sohowww.nascom.nasa.gov/ #12;Experimental Plasma · Formed by collisional excitation of gas in an electric field Electrode Non

  1. Tool kit for space plasma physics

    E-print Network

    Demoulin, Pascal

    2 Tool kit for space plasma physics Most of the Universe is made of plasma. And yet, plasmas kit for space plasma physics Figure 2.1 Solids, liquids and gases abound on the Earth, but most plasma physics: non-Maxwellian distributions, which are ubiquitous in the heliosphere ­ fooling our

  2. Review of Atomic Physics of Dense Plasmas

    Microsoft Academic Search

    Richard M. More

    2003-01-01

    Atomic physics of dense plasmas is a fascinating, complex and often difficult topic in plasma physics that draws from many scientific disciplines and is an integral part of the description of high energy-density plasmas, magnetic fusion plasmas, laser-plasma interactions and the science of warm condensed matter. In this talk, characteristic \\

  3. BOOK REVIEW: Principles of Plasma Spectroscopy

    Microsoft Academic Search

    H. R. Griem

    1998-01-01

    This book gives a comprehensive treatment of plasma spectroscopy, the quantitative study of line and continuous radiation from high temperature plasmas. This highly interdisciplinary field combines elements of atomic, plasma and statistical physics, and has wide application to simulations and diagnostics of laboratory and astrophysical plasmas. Plasma spectroscopy is naturally intertwined with magnetic and inertial fusion energy science. Radiative processes

  4. Plasma Processing Modeling and Databases

    NASA Astrophysics Data System (ADS)

    Morgan, W. L.

    1998-10-01

    I will review the availability of atomic and molecular data for use in plasma processing chemistry modeling. The emphasis will be on plasma chemistries for low pressure semiconductor processing using gases such as C_2F_6, c-C_4F_8, CHF_3, and BCl_3. I will discuss the sources of cross sections and other data and how one evaluates data, assembles plasma chemistry models, and validates such models. Finally I will discuss the possibilities available now and in the near future for on-line plasma chemistry that may be directly accessible by modeling codes. databases

  5. The ``sources`` of plasma physics

    SciTech Connect

    Chen, F.F. [Univ. of California, Los Angeles, CA (United States)

    1994-12-31

    A case is made for the following assertion: every significant advance in the understanding of plasma behavior has been the result of the invention of a new type of plasma source. The duoplasmatron source led to the observation of collisionless electron plasma waves. The hot house slow pinch allowed Alfven waves to be seen. The Q-machine led to the observation of ion acoustic waves and ion Landau damping and to the discovery of electrostatic ion cyclotron waves and drift waves. The double-plasma device permitted ion shocks, solitons, and double-layers to be studied. The large-area cathode discharge led to new discoveries in whistler propagation, current flow across magnetic fields, and filamentation of ionospheric currents. The laser-heated arc has been used to isolate the parametric instabilities of laser fusion and to demonstrate plasma-based particle acceleration. Even the tokamak H-mode can be considered a new plasma source, leading to their (future) understanding of instabilities in sheared electric fields. As plasma physics moves on to new horizons, the venerable gas discharge is coming back into vogue. In particular, low pressure rf discharges are being considered as replacements for the parallel capacitor discharge, which has so far served well the large semiconductor and flat-panel display industries. This talk will include their latest results on helicon wave plasma generators, as well as previously unpublished experiments using other plasma sources.

  6. Plasma contacting - An enabling technology

    NASA Technical Reports Server (NTRS)

    Williams, John D.; Wilbur, Paul J.

    1989-01-01

    An experimental study of plasma contacting with an emphasis on the electron collection mode of this process is described. Results illustrating variations in plasma property profiles and potential differences that develop at hollow cathode plasma contactors are presented. A model of the electron collection plasma contacting process that is consistent with experimentally measured results is reviewed. The shortcomings of laboratory results as direct predictors of contactor performance in space and their usefulness in validating numerical models of the contacting process, that can be used to predict such performance, are discussed.

  7. Autoresonant excitation of antiproton plasmas.

    PubMed

    Andresen, G B; Ashkezari, M D; Baquero-Ruiz, M; Bertsche, W; Bowe, P D; Butler, E; Carpenter, P T; Cesar, C L; Chapman, S; Charlton, M; Fajans, J; Friesen, T; Fujiwara, M C; Gill, D R; Hangst, J S; Hardy, W N; Hayden, M E; Humphries, A J; Hurt, J L; Hydomako, R; Jonsell, S; Madsen, N; Menary, S; Nolan, P; Olchanski, K; Olin, A; Povilus, A; Pusa, P; Robicheaux, F; Sarid, E; Silveira, D M; So, C; Storey, J W; Thompson, R I; van der Werf, D P; Wurtele, J S; Yamazaki, Y

    2011-01-14

    We demonstrate controllable excitation of the center-of-mass longitudinal motion of a thermal antiproton plasma using a swept-frequency autoresonant drive. When the plasma is cold, dense, and highly collective in nature, we observe that the entire system behaves as a single-particle nonlinear oscillator, as predicted by a recent theory. In contrast, only a fraction of the antiprotons in a warm plasma can be similarly excited. Antihydrogen was produced and trapped by using this technique to drive antiprotons into a positron plasma, thereby initiating atomic recombination. PMID:21405235

  8. Vacuum Plasma Spraying Replaces Electrodeposition

    NASA Technical Reports Server (NTRS)

    Holmes, Richard R.; Power, Chris; Burns, David H.; Daniel, Ron; Mckechnie, Timothy N.

    1992-01-01

    Vacuum plasma spraying used to fabricate large parts with complicated contours and inner structures, without uninspectable welds. Reduces time, and expense of fabrication. Wall of combustion chamber built up inside of outer nickel-alloy jacket by plasma spraying. Particles of metal sprayed partially melted in plasma gun and thrown at supersonic speed toward deposition surface. Vacuum plasma-spray produces stronger bond between the grooves and covering layer completing channels and wall of combustion chamber. In tests, bond withstood pressure of 20 kpsi, three times allowable limit by old method.

  9. Ultrarelativistic Electron-Positron Plasma

    E-print Network

    Markus H. Thoma

    2008-10-06

    Ultrarelativistic electron-positron plasmas can be produced in high-intensity laser fields and play a role in various astrophysical situations. Their properties can be calculated using QED at finite temperature. Here we will use perturbative QED at finite temperature for calculating various important properties, such as the equation of state, dispersion relations of collective plasma modes of photons and electrons, Debye screening, damping rates, mean free paths, collision times, transport coefficients, and particle production rates, of ultrarelativistic electron-positron plasmas. In particular, we will focus on electron-positron plasmas produced with ultra-strong lasers.

  10. Method for generating surface plasma

    DOEpatents

    Miller, Paul A. (Albuquerque, NM); Aragon, Ben P. (Albuquerque, NM)

    2003-05-27

    A method for generating a discharge plasma which covers a surface of a body in a gas at pressures from 0.01 Torr to atmospheric pressure, by applying a radio frequency power with frequencies between approximately 1 MHz and 10 GHz across a plurality of paired insulated conductors on the surface. At these frequencies, an arc-less, non-filamentary plasma can be generated to affect the drag characteristics of vehicles moving through the gas. The plasma can also be used as a source in plasma reactors for chemical reaction operations.

  11. Theory of Space Dusty Plasma

    NASA Astrophysics Data System (ADS)

    Mendis, A.

    2012-12-01

    Ionized gases, contaminated with fine (nanometer to micrometer-sized) charged dust, loosely referred to a dusty plasmas, occur in a wide variety of cosmic and laboratory environments. In this topical review I will discuss the underlying theory of such plasmas, with emphasis on the space environment. Central to the discussion is the electrostatic charging of the dust grains by the various currents that they experience in the plasma and radiative environment in which they are immersed. This charging could lead to both physical and dynamical consequences for the dust as well as for the plasma. Among the physical effects for the dust are electrostatic disruption and electrostatic levitation from charged surfaces. The dynamics of the charged dust is affected by the Lorentz force they experience, since space plasmas are generally magnetized. The physical effects for plasma result from the fact that the dust can act both as a sink and as a source of electrons in different space environments. The dynamical effects on the plasma arise from the fact that the charged dust can alter the phase velocity of normal wave modes (e.g., the Ion acoustic mode) by changing the charge equilibrium in the plasma. Additionally the charged dust can also participate in the wave dynamics, leading, for example, to the very low frequency, novel, "dust-acoustic" wave that has been observed in the laboratory. Finally the possibility that charged dust in a space plasma, may indirectly influence the propagation of electromagnetic radiation through it, will also be, briefly, discussed.

  12. Important plasma problems in astrophysics

    SciTech Connect

    Kulsrud, R.M.

    1995-01-01

    In astrophysics, plasmas occur under very extreme conditions. For example there are ultra strong magnetic fields in neutron stars) relativistic plasmas around black holes and in jets, extremely energetic particles such as cosmic rays in the interstellar medium, extremely dense plasmas in accretion disks, and extremely large magnetic Reynold`s numbers in the interstellar medium. These extreme limits for astrophysical plasmas make plasma phenomena much simpler to analyze in astrophysics than in the laboratory. An understanding of such phenomena often results in an interesting way, by simply taking the extreme limiting case of a known plasma theory. I will describe one of the more exciting examples. I will attempt to convey the excitement I felt when I was first exposed to it. However, not all plasma astrophysical phenomena are so simple. There are certain important plasma phenomena in astrophysics, which have not been so easily resolved. In fact a resolution of them is blocking significant progress in astrophysical research. They have not yet yielded to attacks by theoretical astrophysicists nor to extensive numerical simulation. I will attempt to describe one of the more important of these plasma-astrophysical problems, and discuss why its resolution is so important to astrophysics. This significant example is fast, magnetic reconnection. Another significant example is the large-magnetic-Reynold`s-number MHD dynamos.

  13. Laser plasma accelerators

    SciTech Connect

    Malka, V. [Laboratoire d'Optique Appliquee, ENSTA-ParisTech, CNRS, Ecole Polytechnique, UMR 7639, 91761 Palaiseau (France)

    2012-05-15

    This review article highlights the tremendous evolution of the research on laser plasma accelerators which has, in record time, led to the production of high quality electron beams at the GeV level, using compact laser systems. I will describe the path we followed to explore different injection schemes and I will present the most significant breakthrough which allowed us to generate stable, high peak current and high quality electron beams, with control of the charge, of the relative energy spread and of the electron energy.

  14. Compact Plasma Accelerator

    NASA Technical Reports Server (NTRS)

    Foster, John E.

    2004-01-01

    A plasma accelerator has been conceived for both material-processing and spacecraft-propulsion applications. This accelerator generates and accelerates ions within a very small volume. Because of its compactness, this accelerator could be nearly ideal for primary or station-keeping propulsion for spacecraft having masses between 1 and 20 kg. Because this accelerator is designed to generate beams of ions having energies between 50 and 200 eV, it could also be used for surface modification or activation of thin films.

  15. CTR plasma engineering studies

    SciTech Connect

    Miley, G.H.

    1990-01-01

    The main focus of the work by the Fusion Plasma Engineering Group at the University during the prior contract year involved a study of fusion ash (helium) effects on burn efficiency and on potential ways to control ash buildup. This work has wide application to a variety of fusion reactor concepts, but the immediate application for the present work is in the ARIES tokamak reactor design study now being undertaken by a national design team headed by the UCLA. The examples presented here largely deal with the ARIES-I design which is a D-T device operating in the first instability regime.

  16. Auroral plasma waves

    NASA Technical Reports Server (NTRS)

    Gurnett, Donald A.

    1989-01-01

    A review is given of auroral plasma wave phenomena, starting with the earliest ground-based observations and ending with the most recent satellite observations. Two types of waves are considered, electromagnetic and electrostatic. Electromagnetic waves include auroral kilometric radiation, auroral hiss, ELF noise bands, and low-frequency electric and magnetic noise. Electrostatic waves include upper hybrid resonance emissions, electron cyclotron waves, lower hybrid waves, ion cyclotron waves and broadband electrostatic noise. In each case, a brief overview is given describing the observations, the origin of the instability, and the role of the waves in the physics of the auroral acceleration region.

  17. Modeling of Photoionized Plasmas

    NASA Technical Reports Server (NTRS)

    Kallman, Timothy R.

    2010-01-01

    In this paper I review the motivation and current status of modeling of plasmas exposed to strong radiation fields, as it applies to the study of cosmic X-ray sources. This includes some of the astrophysical issues which can be addressed, the ingredients for the models, the current computational tools, the limitations imposed by currently available atomic data, and the validity of some of the standard assumptions. I will also discuss ideas for the future: challenges associated with future missions, opportunities presented by improved computers, and goals for atomic data collection.

  18. Human Plasma Membrane Receptome

    NSDL National Science Digital Library

    Cell receptor researchers have an excellent online resource in the Human Plasma Membrane Receptome (HPMR) database from the Aaron Hsueh lab, part of the Division of Reproductive Biology at Stanford University Medical Center. The database contains information for over 1000 individual cell receptors and offers a number of search options. For instance, users can navigate a concept map diagram organized by receptor function or browse a phylogenetic tree with receptor families organized by evolutionary relationship. The database provides detailed information for each receptor, including PubMed citations.

  19. Analysis of plasma waves observed within local plasma injections seen in Saturn's magnetosphere

    E-print Network

    Gurnett, Donald A.

    Analysis of plasma waves observed within local plasma injections seen in Saturn's magnetosphere J; published 17 May 2008. [1] Plasma injections or density depletion regions have been reported plasma in a cooler, locally produced plasma background. The injected plasma undergoes dispersion

  20. A dusty plasma device for producing extended, steady state, magnetized, dusty plasma columns

    E-print Network

    Merlino, Robert L.

    A dusty plasma device for producing extended, steady state, magnetized, dusty plasma columns Wenjun with an existing Q machine, to produce extended, steady state, magnetized plasma columns. The dusty plasma device (DPD) is to be used for the investigation of waves in dusty plasmas and of other plasma/dust aspects

  1. LCDProjektorenPlasmaLCDProjektorenPlasmaLCDProjektoren NEC MultiSync EA221WM

    E-print Network

    Ott, Albrecht

    LCD·Projektoren·Plasma·LCD·Projektoren·Plasma·LCD·Projektoren NEC MultiSync® EA221WM Professionelle Office-LCD-Monitore mit herausragender Display-Qualität und ergonomischen, ökologischen Details dem Eco-Modus und dem besonderen Maßstab für CO2- Ausstoß · #12;LCD·Projektoren·Plasma·LCD·Projektoren·Plasma·LCD·Projektoren·Plasma·LCD·Projektoren·Plasma·LCD

  2. Inductively coupled plasma heating in a weakly magnetized plasma

    Microsoft Academic Search

    S. S. Kim; C. S. Chang; N. S. Yoon; Ki-Woong Whang

    1999-01-01

    A one-dimensional analysis of electron heating process in a weakly magnetized, inductively coupled plasma (MICP) is presented. It is found that the main difference in the heating process of a MICP from that of a usual unmagnetized ICP is in that circularly polarized wave modes can exist in the plasma. The right handed circularly polarized wave (R-wave) can propagate into

  3. Maxwell Prize Session: Hot Plasma Effects in Gas Discharge Plasma

    Microsoft Academic Search

    Valery Godyak

    2004-01-01

    Radio frequency (rf) gas discharges have been known for over a century. Recently, interest in low-pressure rf discharges has been revitalized due to great achievements and expectations in using such devices in plasma processing for manufacturing of semiconductor chips and lighting technology. In rf discharges the dominant interaction of the electromagnetic field with the plasma, and thus rf power absorption,

  4. Cold plasma: overview of plasma technologies and applications

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cold plasma is a novel nonthermal food processing technology. It is based on energetic, reactive gases which inactivate contaminating microbes on meats, poultry and fruits and vegetables. The primary modes of action are due to UV light and reactive chemical products of the cold plasma ionization pro...

  5. CHAPTER 6. PLASMA DESCRIPTIONS II: MHD 1 Plasma Descriptions II

    E-print Network

    Callen, James D.

    for the electromagnetic fields. The main equations, properties and applications of the MHD model are developed conditions (Section 6.4), dynamical responses (Section 6.5), and the Alfv`en waves (Section 6.6) that result:31 January 28, 2003 c J.D Callen, Fundamentals of Plasma Physics #12;CHAPTER 6. PLASMA DESCRIPTIONS II: MHD 2

  6. LCDProjektorenPlasmaLCDProjektorenPlasmaLCDProjektoren NEC MultiSync

    E-print Network

    Ott, Albrecht

    LCD·Projektoren·Plasma·LCD·Projektoren·Plasma·LCD·Projektoren NEC MultiSync® LCD2490WUXi² Hochinnovativer LCD-Monitor im Wide Format mit herausragenden ergonomischen und wirtschaftlichen Eigenschaften Funktionen wie CableComp, Digital Uniformity Control (ColorComp) bzw. X-light® Pro · #12;LCD·Projektoren

  7. Plasma Characterization of Electronegatively diluted VHF CCP Plasmas

    Microsoft Academic Search

    Alex Paterson; Ned Hammond; Shahid Rauf; Ed Barnat; Paul Miller; Greg Hebner

    2007-01-01

    In this study, the plasma characteristics of a VHF capacitively-coupled, 300 mm processing system were investigated. Spatially dependent ion and electron density, as well as electron energy distribution functions, were measured for frequencies between 27 and 170 MHz and for gas mixtures containing argon, SF6 and CF4. In argon plasmas, increasing the frequency above 120 MHz changed the ion and

  8. EDITORIAL: 80 Years of Plasma 80 Years of Plasma

    Microsoft Academic Search

    R. N. Franklin; N. St J. Braithwaite

    2009-01-01

    Irving Langmuir proposed the term 'plasma' in a paper in 1928 (Proc. Natl Acad. Sci. USA 14 627-637) to describe a 'region containing balanced charges of ions and electrons'. There does not appear to be any record of the thinking behind this proposal, so it is difficult to be definitive. One idea is that since the Greek word 'plasma' was

  9. A new plasma potential measurement instrument for plasma ion sources

    Microsoft Academic Search

    O. Tarvainen; P. Suominen; H. Koivisto

    2004-01-01

    A very efficient and fast instrument to measure the plasma potential of ion sources has been developed at the Department of Physics, University of Jyväskylä (JYFL). The operating principle of this novel instrument is to apply a decelerating voltage into a mesh located in the beamline of the ion source. The plasma potential is determined by measuring the current at

  10. Undamped electrostatic plasma waves

    SciTech Connect

    Valentini, F.; Perrone, D.; Veltri, P. [Dipartimento di Fisica and CNISM, Universita della Calabria, 87036 Rende (CS) (Italy); Califano, F.; Pegoraro, F. [Dipartimento di Fisica and CNISM, Universita di Pisa, 56127 Pisa (Italy); Morrison, P. J. [Institute for Fusion Studies and Department of Physics, University of Texas at Austin, Austin, Texas 78712-1060 (United States); O'Neil, T. M. [Department of Physics, University of California at San Diego, La Jolla, California 92093 (United States)

    2012-09-15

    Electrostatic waves in a collision-free unmagnetized plasma of electrons with fixed ions are investigated for electron equilibrium velocity distribution functions that deviate slightly from Maxwellian. Of interest are undamped waves that are the small amplitude limit of nonlinear excitations, such as electron acoustic waves (EAWs). A deviation consisting of a small plateau, a region with zero velocity derivative over a width that is a very small fraction of the electron thermal speed, is shown to give rise to new undamped modes, which here are named corner modes. The presence of the plateau turns off Landau damping and allows oscillations with phase speeds within the plateau. These undamped waves are obtained in a wide region of the (k,{omega}{sub R}) plane ({omega}{sub R} being the real part of the wave frequency and k the wavenumber), away from the well-known 'thumb curve' for Langmuir waves and EAWs based on the Maxwellian. Results of nonlinear Vlasov-Poisson simulations that corroborate the existence of these modes are described. It is also shown that deviations caused by fattening the tail of the distribution shift roots off of the thumb curve toward lower k-values and chopping the tail shifts them toward higher k-values. In addition, a rule of thumb is obtained for assessing how the existence of a plateau shifts roots off of the thumb curve. Suggestions are made for interpreting experimental observations of electrostatic waves, such as recent ones in nonneutral plasmas.

  11. Periodically oscillating plasma sphere

    SciTech Connect

    Park, J.; Nebel, R.A.; Stange, S.; Murali, S. Krupakar [Los Alamos National Laboratory, Los Alamos, New Mexico 87544 (United States); University of Wisconsin, Madison, Wisconsin 53706 (United States)

    2005-05-15

    The periodically oscillating plasma sphere, or POPS, is a novel fusion concept first proposed by D. C. Barnes and R. A. Nebel [Fusion Technol. 38, 28 (1998)]. POPS utilizes the self-similar collapse of an oscillating ion cloud in a spherical harmonic oscillator potential well formed by electron injection. Once the ions have been phase-locked, their coherent motion simultaneously produces very high densities and temperatures during the collapse phase of the oscillation. A requirement for POPS is that the electron injection produces a stable harmonic oscillator potential. This has been demonstrated in a gridded inertial electrostatic confinement device and verified by particle simulation. Also, the POPS oscillation has been confirmed experimentally through observation that the ions in the potential well exhibit resonance behavior when driven at the POPS frequency. Excellent agreement between the observed POPS frequencies and the theoretical predictions has been observed for a wide range of potential well depths and three different ion species. Practical applications of POPS require large plasma compressions. These large compressions have been observed in particle simulations, although space charge neutralization remains a major issue.

  12. Undamped electrostatic plasma waves

    NASA Astrophysics Data System (ADS)

    Valentini, F.; Perrone, D.; Califano, F.; Pegoraro, F.; Veltri, P.; Morrison, P. J.; O'Neil, T. M.

    2012-09-01

    Electrostatic waves in a collision-free unmagnetized plasma of electrons with fixed ions are investigated for electron equilibrium velocity distribution functions that deviate slightly from Maxwellian. Of interest are undamped waves that are the small amplitude limit of nonlinear excitations, such as electron acoustic waves (EAWs). A deviation consisting of a small plateau, a region with zero velocity derivative over a width that is a very small fraction of the electron thermal speed, is shown to give rise to new undamped modes, which here are named corner modes. The presence of the plateau turns off Landau damping and allows oscillations with phase speeds within the plateau. These undamped waves are obtained in a wide region of the (k,?R) plane (?R being the real part of the wave frequency and k the wavenumber), away from the well-known "thumb curve" for Langmuir waves and EAWs based on the Maxwellian. Results of nonlinear Vlasov-Poisson simulations that corroborate the existence of these modes are described. It is also shown that deviations caused by fattening the tail of the distribution shift roots off of the thumb curve toward lower k-values and chopping the tail shifts them toward higher k-values. In addition, a rule of thumb is obtained for assessing how the existence of a plateau shifts roots off of the thumb curve. Suggestions are made for interpreting experimental observations of electrostatic waves, such as recent ones in nonneutral plasmas.

  13. Pulsed Plasma Thruster Contamination

    NASA Technical Reports Server (NTRS)

    Myers, Roger M.; Arrington, Lynn A.; Pencil, Eric J.; Carter, Justin; Heminger, Jason; Gatsonis, Nicolas

    1996-01-01

    Pulsed Plasma Thrusters (PPT's) are currently baselined for the Air Force Mightysat II.1 flight in 1999 and are under consideration for a number of other missions for primary propulsion, precision positioning, and attitude control functions. In this work, PPT plumes were characterized to assess their contamination characteristics. Diagnostics included planar and cylindrical Langmuir probes and a large number of collimated quartz contamination sensors. Measurements were made using a LES 8/9 flight PPT at 0.24, 0.39, 0.55, and 1.2 m from the thruster, as well as in the backflow region behind the thruster. Plasma measurements revealed a peak centerline ion density and velocity of approx. 6 x 10(exp 12) cm(exp -3) and 42,000 m/s, respectively. Optical transmittance measurements of the quartz sensors after 2 x 10(exp 5) pulses showed a rapid decrease in plume contamination with increasing angle from the plume axis, with a barely measurable transmittance decrease in the ultraviolet at 90 deg. No change in optical properties was detected for sensors in the backflow region.

  14. Fission-induced plasmas

    NASA Technical Reports Server (NTRS)

    Harries, W. L.; Shiu, Y. J.

    1979-01-01

    The possibility of creating a plasma from fission fragments, and to utilize the energy of the particles to create population inversion that would lead to laser action is investigated. An investigation was made of various laser materials which could be used for nuclear-pumped lasing. The most likely candidate for a fissioning material in the gaseous form is uranium hexafluoride - UF6, and experiments were performed to investigate materials that would be compatible with it. One of the central problems in understanding a fission-induced plasma is to obtain a model of the electron behavior, and some preliminary calculations are presented. In particular, the rates of various processes are discussed. A simple intuitive model of the electron energy distribution function is also shown. The results were useful for considering a mathematical model of a nuclear-pumped laser. Next a theoretical model of a (3)He-Ar nuclear-pumped laser is presented. The theory showed good qualitative agreement with the experimental results.

  15. Modeling plasma behavior in a plasma electrode Pockels cell

    SciTech Connect

    Boley, C.D.; Rhodes, M.A. (Lawrence Livermore National Lab., CA (United States))

    1999-06-01

    The authors present three interrelated models of plasma behavior in a plasma electrode Pockels cell (PEPC). In a PEPC, plasma discharges are formed on both sides of a thin, large-aperture electro-optic crystal (typically KDP). The plasmas act as optically transparent, highly conductive electrodes, allowing uniform application of a longitudinal field to induce birefringence in the crystal. First, they model the plasma in the thin direction, perpendicular to the crystal, via a one-dimensional fluid model. This yields the electron temperature and the density and velocity profiles in this direction as functions of the neutral pressure, the plasma channel width, and the discharge current density. Next, they model the temporal response of the crystal to the charging process, combining a circuit model with a model of the sheath which forms near the crystal boundary. This model gives the time-dependent voltage drop across the sheath as a function of electron density at the sheath entrance. Finally, they develop a two-dimensional MHD model of the planar plasma, in order to calculate the response of the plasma to magnetic fields. They show how the plasma uniformity is affected by the design of the current return, by the longitudinal field from the cathode magnetron, and by fields from other sources. This model also gives the plasma sensitivity to the boundary potential at which the top and bottom of the discharge are held. They validate these models by showing how they explain observations in three large Pockels cells built at Lawrence Livermore National Laboratory.

  16. Arc Plasma Gun With Coaxial Powder Feed

    NASA Technical Reports Server (NTRS)

    Zaplatynsky, Isidor

    1988-01-01

    Redesigned plasma gun provides improved metallic and ceramic coatings. Particles injected directly through coaxial bore in cathode into central region of plasma jet. Introduced into hotter and faster region of plasma jet.

  17. 21 CFR 866.2160 - Coagulase plasma.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 2010-04-01 false Coagulase plasma. 866.2160 Section 866.2160 Food...Microbiology Devices § 866.2160 Coagulase plasma. (a) Identification. Coagulase plasma is a device that consists of...

  18. 21 CFR 866.2160 - Coagulase plasma.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 2011-04-01 false Coagulase plasma. 866.2160 Section 866.2160 Food...Microbiology Devices § 866.2160 Coagulase plasma. (a) Identification. Coagulase plasma is a device that consists of...

  19. 21 CFR 866.2160 - Coagulase plasma.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...2012-04-01 2012-04-01 false Coagulase plasma. 866.2160 Section 866.2160 Food...Microbiology Devices § 866.2160 Coagulase plasma. (a) Identification. Coagulase plasma is a device that consists of...

  20. 21 CFR 866.2160 - Coagulase plasma.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...2013-04-01 2013-04-01 false Coagulase plasma. 866.2160 Section 866.2160 Food...Microbiology Devices § 866.2160 Coagulase plasma. (a) Identification. Coagulase plasma is a device that consists of...

  1. 21 CFR 866.2160 - Coagulase plasma.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...2014-04-01 2014-04-01 false Coagulase plasma. 866.2160 Section 866.2160 Food...Microbiology Devices § 866.2160 Coagulase plasma. (a) Identification. Coagulase plasma is a device that consists of...

  2. How non-adiabatic passing electron layers of linear microinstabilities affect turbulent transport

    NASA Astrophysics Data System (ADS)

    Dominski, J.; Brunner, S.; Görler, T.; Jenko, F.; Told, D.; Villard, L.

    2015-06-01

    The response of passing electrons in ion temperature gradient and trapped electron mode microturbulence regimes is investigated in tokamak geometry making use of the flux-tube version of the gyrokinetic code GENE. Results are obtained using two different electron models, fully kinetic and hybrid in which passing particles are forced to respond adiabatically, while trapped are handled kinetically. Comparing linear eigenmodes obtained with these two models enables to systematically isolate fine radial structures located at corresponding mode rational surfaces, clearly resulting from the non-adiabatic passing-electron response. Non-linear simulations show that these fine structures on the non-axisymmetric modes survive in the turbulent phase. Furthermore, through non-linear coupling to axisymmetric modes, they induce radial modulations in the effective profiles of density, ion/electron temperature, and E × B shearing rate. Finally, the passing-electron channel is shown to significantly contribute to the transport levels, at least in our ion temperature gradient case. Also shown is that the passing electrons significantly influence the E × B saturation mechanism of turbulence fluxes.

  3. Collisionless microinstabilities in stellarators. III. The ion-temperature-gradient mode

    SciTech Connect

    Plunk, G. G., E-mail: gplunk@ipp.mpg.de; Helander, P.; Xanthopoulos, P. [Max Planck Institute for Plasma Physics, EURATOM Association, Wendelsteinstr. 1, 17491 Greifswald (Germany) [Max Planck Institute for Plasma Physics, EURATOM Association, Wendelsteinstr. 1, 17491 Greifswald (Germany); Max-Planck/Princeton Research Center for Plasma Physics, 17491 Greifswald (Germany); Connor, J. W. [Euratom/CCFE Fusion Association, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom)] [Euratom/CCFE Fusion Association, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom)

    2014-03-15

    We investigate the linear theory of the ion-temperature-gradient (ITG) mode, with the goal of developing a general understanding that may be applied to stellarators. We highlight the Wendelstein 7X (W7-X) device. Simple fluid and kinetic models that follow closely from existing literature are reviewed and two new first-principle models are presented and compared with results from direct numerical simulation. One model investigates the effect of regions of strong localized shear, which are generic to stellarator equilibria. These “shear spikes” are found to have a potentially significant stabilizing affect on the mode; however, the effect is strongest at short wavelengths perpendicular to the magnetic field, and it is found to be significant only for the fastest growing modes in W7-X. A second model investigates the long-wavelength limit for the case of negligible global magnetic shear. The analytic calculation reveals that the effect of the curvature drive enters at second order in the drift frequency, confirming conventional wisdom that the ITG mode is slab-like at long wavelengths. Using flux tube simulations of a zero-shear W7-X configuration, we observe a close relationship to an axisymmetric configuration at a similar parameter point. It is concluded that scale lengths of the equilibrium gradients constitute a good parameter space to characterize the ITG mode. Thus, to optimize the magnetic geometry for ITG mode stability, it may be fruitful to focus on local parameters, such as the magnitude of bad curvature, connection length, and local shear at locations of bad curvature (where the ITG mode amplitude peaks)

  4. Hanbit microwave plasma diagnostic system

    Microsoft Academic Search

    B. C. Kim; K. D. Lee; S. M. Hwang; G. S. Lee; K. H. Chung

    1999-01-01

    As a part of the plasma diagnostic system for the Hanbit device, various microwave plasma diagnostic systems have been designed and developed from the initial stage of the Hanbit project. These include the interferometer, reflectometer, and electron cyclotron emission radiometer. In this work, we present the current activities related to the development of the microwave diagnostic systems. The brief descriptions

  5. The plasma system of RFX

    Microsoft Academic Search

    F Gnesotto; P Sonato; W. R Baker; A Doria; F Elio; M Fauri; P Fiorentin; G Marchiori; G Zollino

    1995-01-01

    The “plasma system” of RFX includes the first wall, the vacuum vessel, the stabilizing shell, the vacuum and gas injection system, the remote handling system and the relevant auxiliary plants (cooling, baking, glow discharge cleaning, etc.).Since no limiters are provided, the full energy and particle flux from the plasma must be absorbed by the first wall. Taking into account the

  6. Model for resonant plasma probe.

    SciTech Connect

    Warne, Larry Kevin; Johnson, William Arthur; Hebner, Gregory Albert; Jorgenson, Roy E.; Coats, Rebecca Sue

    2007-04-01

    This report constructs simple circuit models for a hairpin shaped resonant plasma probe. Effects of the plasma sheath region surrounding the wires making up the probe are determined. Electromagnetic simulations of the probe are compared to the circuit model results. The perturbing effects of the disc cavity in which the probe operates are also found.

  7. Hollow Plasma in a Solenoid

    SciTech Connect

    Anders, Andre; Kauffeldt, Marina; Oks, Efim M.; Roy, Prabir K.

    2010-11-30

    A ring cathode for a pulsed, high-current, multi-spot cathodic arc discharge was placed inside a pulsed magnetic solenoid. Photography is used to evaluate the plasma distribution. The plasma appears hollow for cathode positions close the center of the solenoid, and it is guided closer to the axis when the cathode is away from the center.

  8. Polarization spectroscopy of tokamak plasmas

    SciTech Connect

    Wroblewski, D.

    1991-09-01

    Measurements of polarization of spectral lines emitted by tokamak plasmas provide information about the plasma internal magnetic field and the current density profile. The methods of polarization spectroscopy, as applied to the tokamak diagnostic, are reviewed with emphasis on the polarimetry of motional Stark effect in hydrogenic neutral beam emissions. 25 refs., 7 figs.

  9. Collective processes in complex plasmas

    Microsoft Academic Search

    P. K. Shukla

    2000-01-01

    During the last decade, we have seen a very rapid growth of the dusty plasma physics with many discoveries. The latter include the dust acoustic wave, the wakefield and the ion focusing (which are responsible for the attraction of charged dust grains), the dusty plasma crystals as well as coherent nonlinear structures comprising the dust ion-acoustic shocks, the dust acoustic

  10. Michigan Institute for Plasma Sci-

    E-print Network

    Shyy, Wei

    of different types of living organisms, cells and tissues and of sterilizing temperature sensitive medical activity in living tissues and organisms. This activity can be adjusted by tuning plasma properties of Direct Non-Thermal Plasma Interaction with Living Tissue Prof. Alexander Fridman Drexel University

  11. Modelling of LIBS plasma expansion

    Microsoft Academic Search

    G. Colonna; A. Casavola; M. Capitelli

    2001-01-01

    A one-dimensional time-dependent fluid dynamic model has been developed to describe the expansion of the plume produced by laser ablation. The model includes chemical reactions considered in local thermodynamic equilibrium to describe the expansion of a TiO plasma. The results are discussed in connection with LIBS plasmas.

  12. Gas lens laser produced plasma.

    PubMed

    Notcutt, M; Waltham, J A; Michaelis, M M; Cunningham, P F; Cazalet, R S

    1989-07-01

    A gas lens is used to focus a megawatt ruby laser beam on to a target to create a plasma. By using focal plane photographs and Faraday cup plasma diagnostics, the focusing ability of a gas lens is compared with an equivalent glass lens. In this experiment the gas lens compares favorably when the laser beam has a divergence of ~1 mrad. PMID:20555544

  13. NRL Plasma Formulary: Revised 1998

    NSDL National Science Digital Library

    The latest edition of the US Naval Research Laboratory's NRL Plasma Formulary, (discussed in the November 27, 1997 Scout Report) is available. This "mini-bible" for plasma physicists compiles a variety of pertinent mathematical and scientific formulas. Available in three formats, the formulary can be downloaded in its entirety or by thematic section.

  14. Biocompatibility of plasma nanostructured biopolymers

    NASA Astrophysics Data System (ADS)

    Slepi?ková Kasálková, N.; Slepi?ka, P.; Ba?áková, L.; Sajdl, P.; Švor?ík, V.

    2013-07-01

    Many areas of medicine such as tissue engineering requires not only mastery of modification techniques but also thorough knowledge of the interaction of cells with solid state substrates. Plasma treatment can be used to effective modification, nanostructuring and therefore can significantly change properties of materials. In this work the biocompatibility of the plasma nanostructured biopolymers substrates was studied. Changes in surface chemical structure were studied by X-ray photoelectron spectroscopy (XPS). The morphology pristine and modified samples were determined using atomic force microscopy (AFM). The surface wettability was determined by goniometry from contact angle. Biocompatibility was determined by in vitro tests, the rat vascular smooth muscle cells (VSMCs) were cultivated on the pristine and plasma modified biopolymer substrates. Their adhesion, proliferation, spreading and homogeneous distribution on polymers was monitored. It was found that the plasma treatment leads to rapid decrease of contact angle for all samples. Contact angle decreased with increasing time of modification. XPS measurements showed that plasma treatment leads to changes in ratio of polar and non-polar groups. Plasma modification was accompanied by a change of surface morphology. Biological tests found that plasma treatment have positive effect on cells adhesion and proliferation cells and affects the size of cell's adhesion area. Changes in plasma power or in exposure time influences the number of adhered and proliferated cells and their distribution on biopolymer surface.

  15. A large volume plasma device

    NASA Astrophysics Data System (ADS)

    Mattoo, S. K.; Anitha, V. P.; Awasthi, L. M.; Ravi, G.

    2001-10-01

    Investigation of highly complex electromagnetic phenomena responsible for fundamental processes in geospace plasma calls for a laboratory device, large enough to provide minimum boundary effects on the electromagnetic waves under concern. The production of large volume, uniform, and quiescent plasma of density ˜1012cm-3 requires a suitable large area plasma source. The influence of energetic electrons on the phenomena under study can be eliminated using pulsed, highly reproducible discharges so that the afterglow, devoid of energetic electrons, becomes the experimental plasma. Measurement over a large volume with high spatial and temporal resolution, acquisition, and storage of voluminous data form other difficult tasks. The requirement to have tasks of plasma generation, wave excitation, and data acquisition automatically sequenced, also demands a sophisticated control system. A large volume plasma device (LVPD), possessing the following unique features, has been developed in our laboratory: (i) a large area multifilamentary source, (ii) a pulsed power system (width ?15 ms and turn off time ?10 ?s), (iii) a three-axes probe drive, (iv) data acquisition and control system with 1 GS/s sampling rate and ?20 GB memory, and (v) an extended magnet coil system giving desired field profile. The achieved plasma parameters include, ne˜1012cm-3, Te?8 eV in the main glow, and ne?3×1011cm-3 and Te?2 eV in the after glow, and plasma uniformity within 5% over 1 m in axial and radial extents. The present article describes the LVPD device.

  16. Current Drive in Recombining Plasma

    SciTech Connect

    P.F. Schmit and N.J. Fisch

    2012-05-15

    The Langevin equations describing the average collisional dynamics of suprathermal particles in nonstationary plasma remarkably admit an exact analytical solution in the case of recombining plasma. The current density produced by arbitrary particle fluxes is derived including the effect of charge recombination. Since recombination has the effect of lowering the charge density of the plasma, thus reducing the charged particle collisional frequencies, the evolution of the current density can be modified substantially compared to plasma with fixed charge density. The current drive efficiency is derived and optimized for discrete and continuous pulses of current, leading to the discovery of a nonzero "residual" current density that persists indefinitely under certain conditions, a feature not present in stationary plasmas.

  17. Current drive in recombining plasma

    SciTech Connect

    Schmit, P. F.; Fisch, N. J. [Department of Astrophysical Sciences, Princeton University, Princeton, New Jersey 08544 (United States)

    2011-10-15

    The Langevin equations describing the average collisional dynamics of suprathermal particles in nonstationary plasma remarkably admit an exact analytical solution in the case of recombining plasma. The current density produced by arbitrary particle fluxes is derived including the influence of charge recombination. Since recombination has the effect of lowering the charge density of the plasma, thus reducing the charged particle collisional frequencies, the evolution of the current density can be modified substantially compared to plasma with fixed charge density. The current drive efficiency is derived and optimized for discrete and continuous pulses of current, leading to the discovery of a nonzero ''residual'' current density that persists indefinitely under certain conditions, a feature not present in stationary plasmas.

  18. Current drive in recombining plasma

    NASA Astrophysics Data System (ADS)

    Schmit, P. F.; Fisch, N. J.

    2011-10-01

    The Langevin equations describing the average collisional dynamics of suprathermal particles in nonstationary plasma remarkably admit an exact analytical solution in the case of recombining plasma. The current density produced by arbitrary particle fluxes is derived including the influence of charge recombination. Since recombination has the effect of lowering the charge density of the plasma, thus reducing the charged particle collisional frequencies, the evolution of the current density can be modified substantially compared to plasma with fixed charge density. The current drive efficiency is derived and optimized for discrete and continuous pulses of current, leading to the discovery of a nonzero "residual" current density that persists indefinitely under certain conditions, a feature not present in stationary plasmas.

  19. Pair plasma relaxation time scales.

    PubMed

    Aksenov, A G; Ruffini, R; Vereshchagin, G V

    2010-04-01

    By numerically solving the relativistic Boltzmann equations, we compute the time scale for relaxation to thermal equilibrium for an optically thick electron-positron plasma with baryon loading. We focus on the time scales of electromagnetic interactions. The collisional integrals are obtained directly from the corresponding QED matrix elements. Thermalization time scales are computed for a wide range of values of both the total-energy density (over 10 orders of magnitude) and of the baryonic loading parameter (over 6 orders of magnitude). This also allows us to study such interesting limiting cases as the almost purely electron-positron plasma or electron-proton plasma as well as intermediate cases. These results appear to be important both for laboratory experiments aimed at generating optically thick pair plasmas as well as for astrophysical models in which electron-positron pair plasmas play a relevant role. PMID:20481841

  20. Photovoltaic Plasma Interaction Test 2

    NASA Technical Reports Server (NTRS)

    Kaufman, Bradford A.; Chrulski, Daniel; Myers, Roger M.

    1996-01-01

    The International Space Station (ISS) program is developing a plasma contactor to mitigate the harmful effects of charge collection on the station's large photovoltaic arrays. The purpose of the present test was to examine the effects of charge collection on the solar array electrical circuit and to verify the effectiveness of the plasma contactor. The results showed that the plasma contactor was able to eliminate structure arcing for any array output voltage. However, the current requirements of the plasma contactor were higher than those for prior testing and predicted by analysis. Three possible causes for this excess current demand are discussed. The most likely appeared to be a high local pressure on or very near the surface of the array as a result of vacuum tank conditions. Therefore, in actual space conditions, the plasma contactor should work as predicted.

  1. Filters for cathodic arc plasmas

    DOEpatents

    Anders, Andre (Albany, CA); MacGill, Robert A. (Richmond, CA); Bilek, Marcela M. M. (Engadine, AU); Brown, Ian G. (Berkeley, CA)

    2002-01-01

    Cathodic arc plasmas are contaminated with macroparticles. A variety of magnetic plasma filters has been used with various success in removing the macroparticles from the plasma. An open-architecture, bent solenoid filter, with additional field coils at the filter entrance and exit, improves macroparticle filtering. In particular, a double-bent filter that is twisted out of plane forms a very compact and efficient filter. The coil turns further have a flat cross-section to promote macroparticle reflection out of the filter volume. An output conditioning system formed of an expander coil, a straightener coil, and a homogenizer, may be used with the magnetic filter for expanding the filtered plasma beam to cover a larger area of the target. A cathodic arc plasma deposition system using this filter can be used for the deposition of ultrathin amorphous hard carbon (a-C) films for the magnetic storage industry.

  2. Twisted waves in a plasma

    NASA Astrophysics Data System (ADS)

    Mendonça, J. T.

    2012-12-01

    We discuss the properties of twisted waves in a plasma, carrying orbital angular momentum. New wave phenomena associated with these waves can be explored in plasma physics. Angular momentum states of electrostatic and electromagnetic fields are introduced. These states can be excited by various methods, including plasma rotation and nonlinear wave mixing. The exchange of angular momentum between electromagnetic and electrostatic waves in a plasma can be achieved by stimulated Raman and Brillouin scattering processes. The description of such processes is based on nonlinearly coupled paraxial equations. Other new effects due to wave vorticity can be observed in plasmas. In particular, intense magnetic fields associated with the inverse Faraday effect can be generated by linearly polarized laser beams, thus changing our traditional view of this effect.

  3. Plasma treatment advantages for textiles

    E-print Network

    Sparavigna, Amelia

    2008-01-01

    The textile industry is searching for innovative production techniques to improve the product quality, as well as society requires new finishing techniques working in environmental respect. Plasma surface treatments show distinct advantages, because they are able to modify the surface properties of inert materials, sometimes with environment friendly devices. For fabrics, cold plasma treatments require the development of reliable and large systems. Such systems are now existing and the use of plasma physics in industrial problems is rapidly increasing. On textile surfaces, three main effects can be obtained depending on the treatment conditions: the cleaning effect, the increase of microroughness (anti-pilling finishing of wool) and the production of radicals to obtain hydrophilic surfaces. Plasma polymerisation, that is the deposition of solid polymeric materials with desired properties on textile substrates, is under development. The advantage of such plasma treatments is that the modification turns out to ...

  4. Method & apparatus for monitoring plasma processing operations

    DOEpatents

    Smith, Jr., Michael Lane; Ward, Pamela Denise; Stevenson, Joel O'Don

    2004-10-19

    The invention generally relates to various aspects of a plasma process and, more specifically, to the monitoring of such plasma processes. One aspect relates to a plasma monitoring module that may be adjusted in at least some manner so as to re-evaluate a previously monitored plasma process. For instance, optical emissions data on a plasma process that was previously monitored by the plasma monitoring module may be replayed through the plasma monitoring module after making at least one adjustment in relation to the plasma monitoring module.

  5. Aerospace applications of pulsed plasmas

    NASA Astrophysics Data System (ADS)

    Starikovskiy, Andrey

    2012-10-01

    The use of a thermal equilibrium plasma for combustion control dates back more than a hundred years to the advent of internal combustion (IC) engines and spark ignition systems. The same principles are still applied today to achieve high efficiency in various applications. Recently, the potential use of nonequilibrium plasma for ignition and combustion control has garnered increasing interest due to the possibility of plasma-assisted approaches for ignition and flame stabilization. During the past decade, significant progress has been made toward understanding the mechanisms of plasma chemistry interactions, energy redistribution and the nonequilibrium initiation of combustion. In addition, a wide variety of fuels have been examined using various types of discharge plasmas. Plasma application has been shown to provide additional combustion control, which is necessary for ultra-lean flames, high-speed flows, cold low-pressure conditions of high-altitude gas turbine engine (GTE) relight, detonation initiation in pulsed detonation engines (PDE) and distributed ignition control in homogeneous charge-compression ignition (HCCI) engines, among others. The present paper describes the current understanding of the nonequilibrium excitation of combustible mixtures by electrical discharges and plasma-assisted ignition and combustion. Nonequilibrium plasma demonstrates an ability to control ultra-lean, ultra-fast, low-temperature flames and appears to be an extremely promising technology for a wide range of applications, including aviation GTEs, piston engines, ramjets, scramjets and detonation initiation for pulsed detonation engines. To use nonequilibrium plasma for ignition and combustion in real energetic systems, one must understand the mechanisms of plasma-assisted ignition and combustion and be able to numerically simulate the discharge and combustion processes under various conditions.

  6. Plasma vertical stabilisation in ITER

    NASA Astrophysics Data System (ADS)

    Gribov, Y.; Kavin, A.; Lukash, V.; Khayrutdinov, R.; Huijsmans, G. T. A.; Loarte, A.; Snipes, J. A.; Zabeo, L.

    2015-07-01

    This paper describes the progress in analysis of the ITER plasma vertical stabilisation (VS) system since its design review in 2007–2008. Two indices characterising plasma VS were studied. These are (1) the maximum value of plasma vertical displacement due to free drift that can be stopped by the VS system and (2) the maximum root mean square value of low frequency noise in the dZ/dt measurement signal used in the VS feedback loop. The first VS index was calculated using the PET code for 15 MA plasmas with the nominal position and shape. The second VS index was studied with the DINA code in the most demanding simulations for plasma magnetic control of 15 MA scenarios with the fastest plasma current ramp-up and early X-point formation, the fastest plasma current ramp-down in a divertor configuration, and an H to L mode transition at the current flattop. The studies performed demonstrate that the VS in-vessel coils, adopted recently in the baseline design, significantly increase the range of plasma controllability in comparison with the stabilising systems VS1 and VS2, providing operating margins sufficient to achieve ITER's goals specified in the project requirements. Additionally two sets of the DINA code simulations were performed with the goal of assessment of the capability of the PF system with the VS in-vessel coils: (i) to control the position of runaway electrons generated during disruptions in 15 MA scenarios and (ii) to trigger ELMs in H-mode plasmas of 7.5 MA/2.65 T scenarios planned for the early phase of ITER operation. It was also shown that ferromagnetic structures of the vacuum vessel (ferromagnetic inserts) and test blanket modules insignificantly affect the plasma VS.

  7. Use of plasma volume substitutes and plasma in developing countries*

    PubMed Central

    Lundsgaard-Hansen, P.; Collins, J. A.; David-West, A. S.; Lopez, C. G.; Hantchef, Z. S.; Lothe, F.; von Steffens, E.

    1983-01-01

    Plasma and plasma substitutes are used in the treatment of various conditions such as haemorrhage and shock. This article examines the role of crystalloids, artificial colloids, human plasma, human albumin, and plasma protein fraction, in the treatment of such patients, with particular reference to peripheral health facilities in developing countries. It is concluded that 0.9% saline, together with 5-6% dextrose, is of particular importance in this situation since it is easy to produce locally, is stable at high temperatures, and has a low cost/benefit ratio. The second priority is to ensure the availability of a limited quantity of one or more colloid plasma substitutes. In the field of plasma, fresh frozen or fresh liquid plasma is most useful for the treatment of various haemostatic derangements and follow-up treatment of severe burns, since it contains the widest spectrum of therapeutically useful components and can be produced locally with an acceptable degree of difficulty. The treatment of severe diarrhoea with special alkaline electrolyte solutions and oral rehydration solutions is also outlined. PMID:6188548

  8. Surface plasma source with anode layer plasma accelerator

    SciTech Connect

    Dudnikov, Vadim [Muons, Inc., Batavia, Illinois 60510 (United States)

    2012-02-15

    Proposed plasma generation system can be used for high current negative ion beam production and for directed deposition by flux of sputtered neutrals and negative ions. The main mechanism of negative ion formation in surface plasma sources is the secondary emission from low work function surface bombarded by a flux of positive ion or neutrals. The emission of negative ions is enhanced significantly by introducing a small amount of cesium or other substance with low ionization potential. In the proposed source are used positive ions generated by Hall drift plasma accelerator (anode layer plasma accelerator or plasma accelerator with insulated channel, with cylindrical or race track configuration of emission slit). The target-emitter is bombarded by the ion beam accelerated in crossed ExB fields. Negative ions are extracted from the target surface with geometrical focusing and are accelerated by negative voltage applied between emitter and plasma, contacting with the plasma accelerator. Hall drift ion source has a special design with a space for passing of the emitted negative ions and sputtered particles through the positive ion source.

  9. Experimental investigation of plasma relaxation using a compact coaxial magnetized plasma gun in a background plasma

    NASA Astrophysics Data System (ADS)

    Zhang, Yue; Lynn, Alan; Gilmore, Mark; Hsu, Scott; University of New Mexico Collaboration; Los Alamos National Laboratory Collaboration

    2013-10-01

    A compact coaxial plasma gun is employed for experimental studies of plasma relaxation in a low density background plasma. Experiments are being conducted in the linear HelCat device at UNM. These studies will advance the knowledge of basic plasma physics in the areas of magnetic relaxation and space and astrophysical plasmas, including the evolution of active galactic jets/radio lobes within the intergalactic medium. The gun is powered by a 120pF ignitron-switched capacitor bank which is operated in a range of 5-10 kV and ~100 kA. Multiple diagnostics are employed to investigate plasma relaxation process. Magnetized Argon plasma bubbles with velocities ~1.2Cs and densities ~1020 m-3 have been achieved. Different distinct regimes of operation with qualitatively different dynamics are identified by fast CCD camera images, with the parameter determining the operation regime. Additionally, a B-dot probe array is employed to measure the spatial toroidal and poloidal magnetic flux evolution to identify detached plasma bubble configurations. Experimental data and analysis will be presented.

  10. Plasma cell leukemia

    PubMed Central

    Albarracin, Flavio; Fonseca, Rafael

    2014-01-01

    Plasma cell leukemia (PCL) is a rare, yet aggressive plasma cell (PC) neoplasm, variant of multiple myeloma (MM), characterized by high levels of PCs circulating in the peripheral blood. PCL can either originate de novo (primary PCL) or as a secondary leukemic transformation of MM (secondary PCL). Presenting signs and symptoms are similar to those seen in MM such as renal insufficiency, hypercalcemia, lytic bone lesions, anemia, and thrombocytopenia, but can also include hepatomegaly and splenomegaly. The diagnostic evaluation of a patient with suspected PCL should include a review of the peripheral blood smear, bone marrow aspiration and biopsy, serum protein electrophoresis (SPEP) with immunofixation, and protein electrophoresis of an aliquot from a 24h urine collection (UPEP). The diagnosis is made when a monoclonal population of PCs is present in the peripheral blood with an absolute PC count exceeding 2000/?L and PC comprising 20% or more of the peripheral blood white cells. The prognosis of PCL is poor with a median survival of 7 to 11 months. Survival is even shorter (2 to 7 months) when PCL occurs in the context of refractory or relapsing MM. There have been no prospective randomized trials investigating the treatment of PCL. Recommendations are primarily based upon data from small retrospective series, case reports, and extrapolation of data from patients with MM. In general, patients are treated with induction therapy followed by hematopoietic cell transplantation (HCT) in those who are appropriate candidates for this approach. The best induction regimen for PCL is not known and there is great variability in clinical practice. Newer agents that are being incorporated into frontline and salvage therapy for MM have also demonstrated activity in PCL such as Immunomodulatory agents and the use of bortezomib with different combinations. PMID:21295388

  11. NCSX Plasma Heating Methods

    SciTech Connect

    H.W. Kugel; D. Spong; R. Majeski; M. Zarnstorff

    2003-02-28

    The NCSX (National Compact Stellarator Experiment) has been designed to accommodate a variety of heating systems, including ohmic heating, neutral-beam injection, and radio-frequency. Neutral beams will provide one of the primary heating methods for NCSX. In addition to plasma heating, beams are also expected to provide a means for external control over the level of toroidal plasma rotation velocity and its profile. The plan is to provide 3 MW of 50 keV balanced neutral-beam tangential injection with pulse lengths of 500 msec for initial experiments, and to be upgradeable to pulse lengths of 1.5 sec. Subsequent upgrades will add 3 MW of neutral-beam injection. This Chapter discusses the NCSX neutral-beam injection requirements and design issues, and shows how these are provided by the candidate PBX-M (Princeton Beta Experiment-Modification) neutral-beam injection system. In addition, estimations are given for beam-heating efficiencies, scaling of heating efficiency with machine size an d magnetic field level, parameter studies of the optimum beam-injection tangency radius and toroidal injection location, and loss patterns of beam ions on the vacuum chamber wall to assist placement of wall armor and for minimizing the generation of impurities by the energetic beam ions. Finally, subsequent upgrades could add an additional 6 MW of radio-frequency heating by mode-conversion ion-Bernstein wave (MCIBW) heating, and if desired as possible future upgrades, the design also will accommodate high-harmonic fast-wave and electron-cyclotron heating. The initial MCIBW heating technique and the design of the radio-frequency system lend themselves to current drive, so that if current drive became desirable for any reason only minor modifications to the heating system described here would be needed. The radio-frequency system will also be capable of localized ion heating (bulk or tail), and possibly ion-Bernstein-wave-generated sheared flows.

  12. NCSX Plasma Heating Methods

    SciTech Connect

    Kugel, H. W.; Spong, D.; Majeski, R.; Zarnstorff, M.

    2008-01-18

    The National Compact Stellarator Experiment (NCSX) has been designed to accommodate a variety of heating systems, including ohmic heating, neutral beam injection, and radio-frequency (rf). Neutral beams will provide one of the primary heating methods for NCSX. In addition to plasma heating, neutral beams are also expected to provide a means for external control over the level of toroidal plasma rotation velocity and its profile. The experimental plan requires 3 MW of 50-keV balanced neutral beam tangential injection with pulse lengths of 500 ms for initial experiments, to be upgradeable to pulse lengths of 1.5 s. Subsequent upgrades will add 3MW of neutral beam injection (NBI). This paper discusses the NCSX NBI requirements and design issues and shows how these are provided by the candidate PBX-M NBI system. In addition, estimations are given for beam heating efficiencies, scaling of heating efficiency with machine size and magnetic field level, parameter studies of the optimum beam injection tangency radius and toroidal injection location, and loss patterns of beam ions on the vacuum chamber wall to assist placement of wall armor and for minimizing the generation of impurities by the energetic beam ions. Finally, subsequent upgrades could add an additional 6 MW of rf heating by mode conversion ion Bernstein wave (MCIBW) heating, and if desired as possible future upgrades, the design also will accommodate high-harmonic fast-wave and electron cyclotron heating. The initial MCIBW heating technique and the design of the rf system lend themselves to current drive, so if current drive became desirable for any reason, only minor modifications to the heating system described here would be needed. The rf system will also be capable of localized ion heating (bulk or tail), and possiblyIBW-generated sheared flows.

  13. Liquid injection plasma deposition method and apparatus

    DOEpatents

    Kong, Peter C. (Idaho Falls, ID); Watkins, Arthur D. (Idaho Falls, ID)

    1999-01-01

    A liquid injection plasma torch deposition apparatus for depositing material onto a surface of a substrate may comprise a plasma torch for producing a jet of plasma from an outlet nozzle. A plasma confinement tube having an inlet end and an outlet end and a central bore therethrough is aligned with the outlet nozzle of the plasma torch so that the plasma jet is directed into the inlet end of the plasma confinement tube and emerges from the outlet end of the plasma confinement tube. The plasma confinement tube also includes an injection port transverse to the central bore. A liquid injection device connected to the injection port of the plasma confinement tube injects a liquid reactant mixture containing the material to be deposited onto the surface of the substrate through the injection port and into the central bore of the plasma confinement tube.

  14. Observation of an ultracold plasma instability

    E-print Network

    Zhang, X L; Rolston, S L

    2008-01-01

    Ultracold plasmas (UCPs), produced by photoionizing of a sample of laser-cooled and trapped atoms, have extended neutral plasma parameters by over two orders of magnitude, to electron temperatures below 1 K \\cite{killian1999}. Studies of UCPs have primarily concentrated on temperature measurements \\cite{roberts2004, gupta2007, fletcher2007}, and expansion dynamics \\cite{kulin2000, bergeson2003, robicheaux2003}, and recent work has identified a stable collective mode \\cite{fletcher2006}. A signature of the collective and nonlinear nature of plasmas is the existence of plasma instabilities, perturbations that grow exponentially to large amplitudes and dominate plasma dynamics. Much of the quest for fusion energy involves control and suppression of plasma instabilities \\cite{conway2000}. This universal dynamics occurs in all kinds of plasmas, including space plasmas \\cite{oppenheim2003, farley1963, buneman1963}, dusty plasmas \\cite{Merlino1998}, magnetically confined plasmas \\cite{krall1971}, and plasmas used fo...

  15. Liquid injection plasma deposition method and apparatus

    DOEpatents

    Kong, P.C.; Watkins, A.D.

    1999-05-25

    A liquid injection plasma torch deposition apparatus for depositing material onto a surface of a substrate may comprise a plasma torch for producing a jet of plasma from an outlet nozzle. A plasma confinement tube having an inlet end and an outlet end and a central bore therethrough is aligned with the outlet nozzle of the plasma torch so that the plasma jet is directed into the inlet end of the plasma confinement tube and emerges from the outlet end of the plasma confinement tube. The plasma confinement tube also includes an injection port transverse to the central bore. A liquid injection device connected to the injection port of the plasma confinement tube injects a liquid reactant mixture containing the material to be deposited onto the surface of the substrate through the injection port and into the central bore of the plasma confinement tube. 8 figs.

  16. Plasma gasification of biomedical waste

    SciTech Connect

    Carter, G.W.; Tsangaris, A.V.

    1995-12-31

    Resorption Canada Limited (RCL) has operated a plasma gasification installation near Ottawa, Ontario, Canada for over ten years; therefore, the salient capabilities and advantages of plasma gasification over other state-of-the-art technologies for environmentally cleaner disposal of a number of waste materials became increasingly clearer as more and more experience was gained. Plasma gasification is a non-incineration thermal process which uses extremely high temperatures to completely decompose input waste material into very simple molecules. The capability to generate such high heat without using oxygen, unlike a combustion flame, and the temperature profile of the hot plasma gases being between 3,000 C and 8,000 C was ideal for the disposal of waste materials through gasification. RCL conducted two major plasma gasification projects with Municipal Solid Waste (MSW) which were highly successful, indicating very clearly that the basic technology for plasma gasification was a very viable alternative to conventional incineration techniques with resultant environmental benefits related to gaseous emission levels and slag properties. The experimentation ended with two tests which included full environmental analyses for each. These results provided the initiative for similar testing with biomedical waste. The work on the plasma gasification of biomedical waste is summarized. The work on MSW is presented in a separate paper.

  17. Plasma Treatments and Biomass Gasification

    NASA Astrophysics Data System (ADS)

    Luche, J.; Falcoz, Q.; Bastien, T.; Leninger, J. P.; Arabi, K.; Aubry, O.; Khacef, A.; Cormier, J. M.; Lédé, J.

    2012-02-01

    Exploitation of forest resources for energy production includes various methods of biomass processing. Gasification is one of the ways to recover energy from biomass. Syngas produced from biomass can be used to power internal combustion engines or, after purification, to supply fuel cells. Recent studies have shown the potential to improve conventional biomass processing by coupling a plasma reactor to a pyrolysis cyclone reactor. The role of the plasma is twofold: it acts as a purification stage by reducing production of tars and aerosols, and simultaneously produces a rich hydrogen syngas. In a first part of the paper we present results obtained from plasma treatment of pyrolysis oils. The outlet gas composition is given for various types of oils obtained at different experimental conditions with a pyrolysis reactor. Given the complexity of the mixtures from processing of biomass, we present a study with methanol considered as a model molecule. This experimental method allows a first modeling approach based on a combustion kinetic model suitable to validate the coupling of plasma with conventional biomass process. The second part of the paper is summarizing results obtained through a plasma-pyrolysis reactor arrangement. The goal is to show the feasibility of this plasma-pyrolysis coupling and emphasize more fundamental studies to understand the role of the plasma in the biomass treatment processes.

  18. Cold plasma decontamination of foods.

    PubMed

    Niemira, Brendan A

    2012-01-01

    Cold plasma is a novel nonthermal food processing technology that uses energetic, reactive gases to inactivate contaminating microbes on meats, poultry, fruits, and vegetables. This flexible sanitizing method uses electricity and a carrier gas, such as air, oxygen, nitrogen, or helium; antimicrobial chemical agents are not required. The primary modes of action are due to UV light and reactive chemical products of the cold plasma ionization process. A wide array of cold plasma systems that operate at atmospheric pressures or in low pressure treatment chambers are under development. Reductions of greater than 5 logs can be obtained for pathogens such as Salmonella, Escherichia coli O157:H7, Listeria monocytogenes, and Staphylococcus aureus. Effective treatment times can range from 120 s to as little as 3 s, depending on the food treated and the processing conditions. Key limitations for cold plasma are the relatively early state of technology development, the variety and complexity of the necessary equipment, and the largely unexplored impacts of cold plasma treatment on the sensory and nutritional qualities of treated foods. Also, the antimicrobial modes of action for various cold plasma systems vary depending on the type of cold plasma generated. Optimization and scale up to commercial treatment levels require a more complete understanding of these chemical processes. Nevertheless, this area of technology shows promise and is the subject of active research to enhance efficacy. PMID:22149075

  19. Plasma diagnostics of non-equilibrium atmospheric plasma jets

    NASA Astrophysics Data System (ADS)

    Shashurin, Alexey; Scott, David; Keidar, Michael; Shneider, Mikhail

    2014-10-01

    Intensive development and biomedical application of non-equilibrium atmospheric plasma jet (NEAPJ) facilitates rapid growth of the plasma medicine field. The NEAPJ facility utilized at the George Washington University (GWU) demonstrated efficacy for treatment of various cancer types (lung, bladder, breast, head, neck, brain and skin). In this work we review recent advances of the research conducted at GWU concerned with the development of NEAPJ diagnostics including Rayleigh Microwave Scattering setup, method of streamer scattering on DC potential, Rogowski coils, ICCD camera and optical emission spectroscopy. These tools allow conducting temporally-resolved measurements of plasma density, electrical potential, charge and size of the streamer head, electrical currents flowing though the jet, ionization front propagation speed etc. Transient dynamics of plasma and discharge parameters will be considered and physical processes involved in the discharge will be analyzed including streamer breakdown, electrical coupling of the streamer tip with discharge electrodes, factors determining NEAPJ length, cross-sectional shape and propagation path etc.

  20. The Absence of Plasma in"Spark Plasma Sintering"

    SciTech Connect

    Hulbert, Dustin M.; Anders, Andre; Dudina, Dina V.; Andersson, Joakim; Jiang, Dongtao; Unuvar, Cosan; Anselmi-Tamburini, Umberto; Lavernia, Enrique J.; Mukherjee, Amiya K.

    2008-04-10

    Spark plasma sintering (SPS) is a remarkable method for synthesizing and consolidating a large variety of both novel and traditional materials. The process typically uses moderate uni-axial pressures (<100 MPa) in conjunction with a pulsing on-off DC current during operation. There are a number of mechanisms proposed to account for the enhanced sintering abilities of the SPS process. Of these mechanisms, the one most commonly put forth and the one that draws the most controversy involves the presence of momentary plasma generated between particles. This study employees three separate experimental methods in an attempt to determine the presence or absence of plasma during SPS. The methods employed include: in-situ atomic emission spectroscopy, direct visual observation and ultra-fast in-situ voltage measurements. It was found using these experimental techniques that no plasma is present during the SPS process. This result was confirmed using several different powders across a wide spectrum of SPS conditions.

  1. Surface plasma source with saddle antenna radio frequency plasma generator.

    PubMed

    Dudnikov, V; Johnson, R P; Murray, S; Pennisi, T; Piller, C; Santana, M; Stockli, M; Welton, R

    2012-02-01

    A prototype RF H(-) surface plasma source (SPS) with saddle (SA) RF antenna is developed which will provide better power efficiency for high pulsed and average current, higher brightness with longer lifetime and higher reliability. Several versions of new plasma generators with small AlN discharge chambers and different antennas and magnetic field configurations were tested in the plasma source test stand. A prototype SA SPS was installed in the Spallation Neutron Source (SNS) ion source test stand with a larger, normal-sized SNS AlN chamber that achieved unanalyzed peak currents of up to 67 mA with an apparent efficiency up to 1.6 mA?kW. Control experiments with H(-) beam produced by SNS SPS with internal and external antennas were conducted. A new version of the RF triggering plasma gun has been designed. A saddle antenna SPS with water cooling is fabricated for high duty factor testing. PMID:22380221

  2. Surface plasma source with saddle antenna radio frequency plasma generatora)

    NASA Astrophysics Data System (ADS)

    Dudnikov, V.; Johnson, R. P.; Murray, S.; Pennisi, T.; Piller, C.; Santana, M.; Stockli, M.; Welton, R.

    2012-02-01

    A prototype RF H- surface plasma source (SPS) with saddle (SA) RF antenna is developed which will provide better power efficiency for high pulsed and average current, higher brightness with longer lifetime and higher reliability. Several versions of new plasma generators with small AlN discharge chambers and different antennas and magnetic field configurations were tested in the plasma source test stand. A prototype SA SPS was installed in the Spallation Neutron Source (SNS) ion source test stand with a larger, normal-sized SNS AlN chamber that achieved unanalyzed peak currents of up to 67 mA with an apparent efficiency up to 1.6 mA/kW. Control experiments with H- beam produced by SNS SPS with internal and external antennas were conducted. A new version of the RF triggering plasma gun has been designed. A saddle antenna SPS with water cooling is fabricated for high duty factor testing.

  3. Multidimensional Plasma Sheath Modeling Using The Three Fluid Plasma Model

    NASA Astrophysics Data System (ADS)

    Lilly, Robert; Shumlak, Uri

    2011-10-01

    There has been renewed interest in the use of plasma actuators for high speed flow control applications. In the plasma actuator, current is driven through the surrounding weakly ionized plasma to impart control moments on the hypersonic vehicle. This expanded study employs the three-fluid (electrons, ions, neutrals) plasma model as it allows the capture of electron inertial effects, as well as energy and momentum transfer between the charged and neutral species. Previous investigations have typically assumed an electrostatic electric field. This work includes the full electrodynamics. Past work was conducted in 1- and 2-D. In this work, the problem is expanded to 3-D with the fluid equations extended from euler to Braginskii.

  4. Effect of plasma surface interactions on PLT plasma parameters

    SciTech Connect

    Meservey, E.B.; Arunasalam, V.; Barnes, C.

    1980-07-01

    This paper gives a brief description of the geometry and parameters of the PLT tokamak, reviews some of the last four years' results that are particularly relevant to plasma-boundary interactions, and then concentrates on two specific problems.

  5. LCDProjektorenPlasmaLCDProjektorenPlasmaLCDProjektoren NEC MultiSync

    E-print Network

    Ott, Albrecht

    Wide (16:10 Format) Office Monitore, die große Flexibilität und herausragende ergonomische NTAA (Non-Touch-Auto-Adjustment)· #12;LCD·Projektoren·Plasma·LCD Einstellungen Advanced NTAA (Advanced Non-Touch-Auto-Adjustment); Auto Adjust; Ecomode; Farbtemperaturkontrolle

  6. A study of solitary plasma rings in axisymmetric plasma configurations

    E-print Network

    Rabga, Tenzin

    2013-01-01

    In this thesis, we search for the plasma and field configurations that can exist under stationary conditions around a collapsed object such as a black hole. Regimes where the iso rotational condition corresponding to ...

  7. Fast pulse nonthermal plasma reactor

    DOEpatents

    Rosocha, Louis A.

    2005-06-14

    A fast pulsed nonthermal plasma reactor includes a discharge cell and a charging assembly electrically connected thereto. The charging assembly provides plural high voltage pulses to the discharge cell. Each pulse has a rise time between one and ten nanoseconds and a duration of three to twenty nanoseconds. The pulses create nonthermal plasma discharge within the discharge cell. Accordingly, the nonthermal plasma discharge can be used to remove pollutants from gases or break the gases into smaller molecules so that they can be more efficiently combusted.

  8. Laboratory experiments on plasma contactors

    NASA Technical Reports Server (NTRS)

    Wilbur, Paul J.; Williams, John D.

    1990-01-01

    Experimental results describing the operation of hollow cathode plasma contactors collecting and emitting electrons from and to an ambient plasma at current levels of the order of one ampere are presented. The voltage drops induced between a contactor and an ambient plasma are shown to be a few tens of volts at such current levels. The development of a double sheath and the production of substantial numbers of ions by electrons streaming across it are associated with the electron collection process. The development of a complex potential structure including a high potential hill just downstream of the cathode orifice is shown to characterize typical contactor emitting electrons.

  9. Radioimmunoassay of ACTH in plasma

    PubMed Central

    Berson, Solomon A.; Yalow, Rosalyn S.

    1968-01-01

    Techniques are described in detail for a radioimmunoassay of plasma adrenocorticotropin (ACTH) that is capable of detecting hormone in unextracted normal human plasma at 1:5 dilution under the conditions described. The sensitivity of the assay is at the level of 1 ??g/ml (equivalent to 0.014 mU/100 ml). In normal subjects ACTH concentrations averaged 22 ??g/ml (equivalent to 0.308 mU/100 ml) plasma at 8-10 a.m. In a smaller group the concentrations averaged 9.6 ??g/ml (equivalent to 0.134 mU/100 ml) at 10-11 p.m. Although a circadian rhythm in normal subjects was not always well marked throughout the daytime hours, plasma ACTH usually fell to its lowest value in the late evening. In hospital patients who were not acutely ill, concentrations were infrequently above 100 ??g/ml in the morning and usually fell to significantly lower levels in the late evening. Severely ill hospital patients occasionally exhibited a.m. concentrations above 200 ??g/ml. In a group of subjects showing frequent spiking of plasma 17-OHCS concentrations throughout the day parallel spiking of plasma ACTH as well was generally observed. Metyrapone produced marked increases in plasma ACTH within 24 hr in all cases and generally within 3-6 hr except when started late in the day. Dexamethasone brought about a persistent reduction in plasma ACTH in a patient under continued treatment with metyrapone. Hypoglycemia, electroshock, surgery under general anesthesia, histalog and vasopressin administration were usually followed by significant increases in plasma ACTH concentration. Prior administration of dexamethasone blocked the response to hypoglycemia. Marked elevations in plasma ACTH were observed in patients with adrenal insufficiency off steroid therapy, in Cushing's disease after adrenalectomy even in the presence of persistent hypercortisolemia, and in some untreated patients with Cushing's disease. Umbilical cord blood contained higher plasma ACTH concentrations than maternal blood at delivery in seven of eight cases. After suppression of ACTH secretion by dexamethasone or cortisol. ACTH disappeared from plasma with half-times ranging from 22 min to 30 min in three cases studied. Images PMID:4302180

  10. Evaporative cooling of flare plasma

    NASA Technical Reports Server (NTRS)

    Antiochos, S. K.; Sturrock, P. A.

    1978-01-01

    We investigate a one-dimensional loop model for the evaporative cooling of the coronal flare plasma. The important assumptions are that conductive losses dominate radiative cooling and that the evaporative velocities are small compared with the sound speed. We calculate the profile and evolution of the temperature and verify the accuracy of our assumptions for plasma parameters typical of flare regions. The model is in agreement with soft X-ray observations on the evolution of flare temperatures and emission measures. The effect of evaporation is to greatly reduce the conductive heat flux into the chromosphere and to enhance the EUV emission from the coronal flare plasma.

  11. Cleaning nanoelectrodes with air plasma.

    PubMed

    Sun, Tong; Blanchard, Pierre-Yves; Mirkin, Michael V

    2015-04-21

    Unlike macroscopic and micrometer-sized solid electrodes whose surface can be reproducibly cleaned by mechanical polishing, cleaning the nanoelectrode surface is challenging because of its small size and extreme fragility. Even very gentle polishing typically changes the nanoelectrode size and geometry, thus, complicating the replication of nanoelectrochemical experiments. In this letter, we show the possibility of cleaning nanoelectrode surfaces nondestructively by using an air plasma cleaner. The effects of plasma cleaning have been investigated by atomic force microscopy (AFM) imaging, voltammetry, and scanning electrochemical microscopy (SECM). A related issue, the removal of an insoluble organic film from the nanoelectrode by plasma cleaning, is also discussed. PMID:25839963

  12. Plasma calorimeter for absorption measurement of laser produced plasma

    SciTech Connect

    Uchida, S.; Tanaka, M.; Sakawa, Y.; Nishimura, H.; Yamanaka, T.; Yamanaka, C.

    1985-10-01

    A new type of plasma calorimeter has been developed for laser light absorption and measurement of laser irradiated targets. The principle of this detector is the same as a bolometer; plasmas and x rays are absorbed by a thin glass plate which is transparent enough for laser light, and temperature rise of the absorber plate is detected by a faint increase of the resistance of a nickel resistance bulb. The structure and application example are described.

  13. The Diagnostics of the External Plasma for the Plasma Rocket

    NASA Technical Reports Server (NTRS)

    Karr, Gerald R.

    1997-01-01

    The plasma rocket is located at NASA Johnson Space Center. To produce a thrust in space. an inert gas is ionized into a plasma and heated in the linear section of a tokamak fusion device to 1 x 10(exp 4) - 1.16 x 10(exp 6)K(p= 10(exp 10) - 10(exp 14)/cu cm ). The magnetic field used to contain the plasma has a magnitude of 2 - 10k Gauss. The plasma plume has a variable thrust and specific impulse. A high temperature retarding potential analyzer (RPA) is being developed to characterize the plasma in the plume and at the edge of the magnetically contained plasma. The RPA measures the energy and density of ions or electrons entering into its solid angle of collection. An oscilloscope displays the ion flux versus the collected current. All measurements are made relative to the facility ground. A RPA is being developed in a process which involves the investigation of several prototypes. The first prototype has been tested on a thermal plasma. The knowledge gained from its development and testing were applied to the development of a RPA for collimated plasma. The prototypes consist of four equally spaced grids and an ion collector. The outermost grid is a ground. The second grid acts as a bias to repel electrons. The third is a variable v voltage ion suppressor. Grid four (inner grid) acts to repel secondary electrons, being biased equal to the first. Knowledge gained during these two stages are being applied to the development of a high temperature RPA Testing of this device involves the determination of its output parameters. sensitivity, and responses to a wide range of energies and densities. Each grid will be tested individually by changing only its voltage and observing the output from the RPA. To verify that the RPA is providing proper output. it is compared to the output from a Langmuir or Faraday probe.

  14. Plasma Gate: Free Software for Atomic and Plasma Physics

    NSDL National Science Digital Library

    Maintained by the Plasma Laboratory of Weizmann Institute of Science, the Free Software for Atomic and Plasma Physics Web site contains over thirty links to various programs. Examples of available software include Weizmann Institutes: 369j-symbol calculator and Russia's Institute of Spectroscopy's spectral bibliography database. Although several of the links currently seem to be dead, the site does give those working in this field access to several sites with useful software programs.

  15. Observation of Plasma Satellite Lines in Laser Produced Plasmas

    Microsoft Academic Search

    D. Riley; O. Willi

    1995-01-01

    The observation of satellite features to He-like emission lines from an aluminum plasma, generated with a short-pulse KrF laser system, is reported. There are interpreted as plasmon-induced satellites of the type described by Lee [J. Phys. B 12, 1165 (1979)]. The plasma density inferred from line broadening is shown to be consistent with the electron density inferred from the frequency

  16. The Diagnostics of the External Plasma for the Plasma Rocket

    NASA Technical Reports Server (NTRS)

    Karr, Gerald R.

    1997-01-01

    Three regions of plasma temperature/energy are being investigated to understand fully the behavior of the plasma created by the propulsion device and the operation of the RPA. Each type of plasma has a RPA associated with it; i.e. a thermal RPA, a collimated RPA, and a high temperature RPA. Through the process of developing the thermal and collimated RPAs, the proper knowledge and experience has been gained to not only design a high temperature RPA for the plasma rocket, but to understand its operation, results, and uncertainty. After completing a literature search for, reading published papers on, and discussing the operation of the RPA with electric propulsion researchers, I applied the knowledge gained to the development of a RPA for thermal plasma. A design of a thermal RPA was made which compensates for a large Debye length and low ionized plasma. From this design a thermal RPA was constructed. It consists of an outer stainless steel casing, a phenolic insulator (outgases slightly), and stainless steel mesh for the voltage screens. From the experience and knowledge gained in the development of the thermal RPA, a RPA for collimated plasma was developed. A collimated RPA has been designed and constructed. It compensate for a smaller Debye length and much higher ionization than that existing in the thermal plasma. It is 17% of the size of the thermal RPA. A stainless steel casing shields the detector from impinging electrons and ions. An insulating material, epoxy resin, was utilized which has a negligible outgassing. This material can be molded in styrofoam and machined quite nicely. It is capable of withstanding moderately high temperatures. Attached to this resin insulator are inconel screens attached by silver plated copper wire to a voltage supply. All the work on the RPAs and thermal ion source, I performed in the University of Alabama in Huntsville's (UAH) engineering machine shop.

  17. Pulse-discharge plasmas for plasma-accelerator applications

    NASA Astrophysics Data System (ADS)

    Clayton, C. E.; Joshi, C.; Lopes, N. C.

    2012-12-01

    For particle-beam-driven plasma wakefield accelerators, a long and fully-ionized plasma is desirable. We describe an experiment at UCLA to develop a prototype of such plasma using a pulsed-current discharge. Scaling of the plasma density with glass-tube diameter and with discharge-circuit parameters is currently underway. We have found that 4 Torr of Argon can be fully ionized to a density of about 1.3 × 1017 cm-3 when the current density in the 1 inch diameter, 1.2 meter-long tube is around 2 kA/cm2, at least at one point along the discharge. The homogeneity of the plasma density in the longitudinal direction is crucial to prevent slippage of the driven plasma structures with the particles. Equally important are the transverse gradients since any dipole asymmetry in the transverse direction can lead to "steering" of the particle beam.[1] The longitudinal and transverse gradients may be a function of time into the discharge, the shape of the electrodes, the tube size, and the fractional ionization for a given fill pressure. These issues are currently under investigation.

  18. Diagnostics of plasma-surface interactions in plasma processes

    NASA Astrophysics Data System (ADS)

    Ishikawa, Kenji

    2014-10-01

    Low temperature plasma including electrons, ions, radicals and photons can be applied because only high temperature of electron but for background gases. Recently plasma applications in biology and medicine have grown significantly. For complexity of mechanisms, it is needed to understand comprehensively the plasma-surface interactions. To diagnose the interactions comprises of three areas; (1) incident species generated in plasmas toward the surface, (2) surface reactions such as scission and bond of chemical bonds, and (3) products after the reactions. Considered with non-linearity of the chemical reactions as changed by an initial state, we have focused and developed to observe dangling bonds in situ at real time by electron spin resonance (ESR). Moreover, individual contribution and simultaneous irradiation of each species such as radicals and photons have been studied in utilization of light shades and windows in similar manner of the pellets for plasma process evaluation (PAPE). As exampled, the interaction of polymeric materials, fungal spores and edible meats with plasmas were studied on the basis of the real time in situ observations of dangling bonds or surface radicals formation.

  19. Nonlinear plasma waves and wavebreaking in quantum plasmas

    NASA Astrophysics Data System (ADS)

    Kull, Hans-Joerg

    2011-10-01

    Large amplitude plasma waves are commonly excited in laser-plasma interactions. One of the basic features of nonlinear plasma waves is wavebreaking when a critical wave amplitude is exceeded. The wavebreaking amplitude was first derived by Dawson for cold plasmas. Later this criterion was generalized to thermal and relativistic plasmas by various authors. In the present work, we consider the wavebreaking limit in warm dense matter. The basic quantum kinetic equation is the quantum Vlasov equation. We propose a numerical method that solves the set of quantum Vlasov-Maxwell equations with the same efficiency as classical particle-in-cell (PIC) simulations. The basic concept of this method consists in a representation of the ensemble by a set of carrier-envelope waves and a propagation of these waves in their rest frames by the time dependent Schrödinger equation. Linear dispersion relations and Landau damping rates can be accurately reproduced by this method. Wavebreaking amplitudes in quantum plasmas are obtained and compared to theoretical results.

  20. Plasma Sheath Modeling Using The Three Fluid Plasma Model

    NASA Astrophysics Data System (ADS)

    Lilly, Robert; Shumlak, Uri

    2010-11-01

    There has been renewed interest in the use of plasma actuators for high speed flow control applications. In the plasma actuator, current is driven through the surrounding weakly ionized plasma to impart control moments on the hypersonic vehicle. Accurate modeling of plasma sheath physics is of particular importance for the plasmas found in high speed flight applications. This study employs the three-fluid (electrons, ions, neutrals) plasma model as it allows the capture of electron inertial effects without the unbounded whistler wave that accompanies Hall MHD, as well as energy and momentum transfer between the charged and neutral species. Previous investigations have typically assumed an electrostatic electric field. This work includes the full electrodynamics. Floating potential sheath formation is investigated initially. We then present a method of voltage control that allows for control of the sheath. The resulting boundary scheme, in conjunction with the use of the purely hyperbolic Maxwells equation set, will be reviewed and the results in 1D and 2D discussed. Finally the outlook for incorporating transport will be presented.

  1. Pulse-discharge plasmas for plasma-accelerator applications

    SciTech Connect

    Clayton, C. E.; Joshi, C.; Lopes, N. C. [Department of Electrical Engineering, University of California at Los Angeles, 405 Hilgard Avenue, Los Angeles, California 90095 (United States); Grupo de Lasers e Plasmas, Instituto de Plasmas e Fusao Nuclear, Instituto Superior Tecnico Av. Rovisco Pais, Lisboa 1049-001 (Portugal)

    2012-12-21

    For particle-beam-driven plasma wakefield accelerators, a long and fully-ionized plasma is desirable. We describe an experiment at UCLA to develop a prototype of such plasma using a pulsed-current discharge. Scaling of the plasma density with glass-tube diameter and with discharge-circuit parameters is currently underway. We have found that 4 Torr of Argon can be fully ionized to a density of about 1.3 Multiplication-Sign 10{sup 17} cm{sup -3} when the current density in the 1 inch diameter, 1.2 meter-long tube is around 2 kA/cm{sup 2}, at least at one point along the discharge. The homogeneity of the plasma density in the longitudinal direction is crucial to prevent slippage of the driven plasma structures with the particles. Equally important are the transverse gradients since any dipole asymmetry in the transverse direction can lead to 'steering' of the particle beam. The longitudinal and transverse gradients may be a function of time into the discharge, the shape of the electrodes, the tube size, and the fractional ionization for a given fill pressure. These issues are currently under investigation.

  2. Thermal plasma chemical synthesis of powders

    SciTech Connect

    Vogt, G.J.; Newkirk, L.R.

    1985-01-01

    Thermal plasma processing has been increasingly used to synthesize submicron powders of high-purity ceramics and metals. The high temperatures generated with the plasma provide a vapor phase reaction zone for elements with high boiling points and refractory materials. An overview is presented on the general plasma technology used in synthesis and on the properties of plasma powders.

  3. Kinetic Studies of Thermal Relaxation in Plasma

    Microsoft Academic Search

    In Soo Ko

    1987-01-01

    Thermal relaxation of plasma is investigated in two cases: two dimensional magnetized plasma and three dimensional unmagnetized plasma. The generalized Lenard -Balescu equation and the Fokker-Planck equation are solved respectively. During the numerical calculation, forward time integration is used in both cases. The Lenard-Balescu equation is generalized for a magnetized plasma from the BBGKY hierarchy equation. The random phase approximation

  4. Relativistic Corrections to Microwave Interferometry in Plasmas

    Microsoft Academic Search

    H. W. Graben

    1963-01-01

    The index of refraction for a plasma with a high electron temperature ; was calculated for plane, transverse waves having frequencies large compared to ; the plasma frequency and to the electron cyclotron frequency. Results indicate ; that microwave phase-shift measurements of the plasma density based on the cold ; plasma relation for the index of refraction tend to be

  5. Transitions Within a Vertically Confined Plasma Crystal

    Microsoft Academic Search

    Ke Qiao; Truell Hyde

    2004-01-01

    Dusty plasmas consist of an ionized gas containing small (usually negatively charged) particles. Dusty plasmas are of interest in both astrophysics and space physics as well as in research in plasma processing and nanofabrication. In this work, the formation of plasma crystals confined in an external one-dimensional parabolic potential well is simulated for a normal experimental environment employing a computer

  6. BOOK REVIEW: Introduction to Dusty Plasma Physics

    Microsoft Academic Search

    P. K. Shukla; A. A. Mamun

    2002-01-01

    The book Introduction to Plasma Physics by Shukla and Mamun deals with various aspects of collective processes in dusty plasmas. The first introductory chapters review dust charging and the forces on dust grains in the plasma. The next two chapters give an elaborate description of the various waves and instabilities present in plasmas. In our opinion this makes the book

  7. Space plasma physics research at NASA

    Microsoft Academic Search

    Stanley D. Shawhan

    1987-01-01

    Space plasma physics research at the National Aeronautics and Space Administration (NASA) is administered by the Space Plasma Physics Branch of the Earth Science and Applications Division of the Office of Space Science and Applications at NASA Headquarters in Washington, D.C. The general goal of the space plasma research program is to understand the fundamental properties of space plasmas and

  8. Plasma Dynamics Group Aerospace & Energetics Research Program

    E-print Network

    Shumlak, Uri

    renewed interest in the use of plasma actuators for high speed flow control applications. In the plasma actuator, current is driven through the surrounding weakly ionized plasma to impart control moments on the hypersonic vehicle. This expanded study employs the three-fluid (electrons, ions, neutrals) plasma model

  9. The physics of laser plasma interactions

    Microsoft Academic Search

    William L. Kruer

    1988-01-01

    Contents, abridged: Computer simulation of plasmas using particle codes. Propagation of obliquely incident light waves. Collisional absorption of electromagnetic waves in plasmas. Parametric excitation of electron and ion waves. Stimulated Raman scattering. Stimulated Brillouin scattering. Heating by plasma waves. Laser plasma experiments.

  10. Recent developments in DBD plasma flow control

    NASA Astrophysics Data System (ADS)

    Wang, Jin-Jun; Choi, Kwing-So; Feng, Li-Hao; Jukes, Timothy N.; Whalley, Richard D.

    2013-10-01

    Flow control using DBD (dielectric-barrier-discharge) plasma actuators is a relatively new, but rapidly expanding area of research. There are a number of review papers available on this subject, but few discuss on their latest developments. The purpose of the present article is to “fill the gap” by reviewing the recent trend of plasma actuator design and to summarise aerodynamic control techniques. Here, we review new plasma actuators, such as plasma synthetic jet actuators, plasma spark jet actuators, three-dimensional plasma actuators and plasma vortex generators, which can induce three-dimensional flows away from the wall. We also review the starting vortex that leads to formation of a plasma wall jet. This is an important subject not only for a better understanding of the flow induced by DBD plasma actuators, but also as a database that can be used to calibrate the numerical models for plasma flow control. Design of DBD plasma actuators to obtain turbulent skin-friction reduction is shown and the modifications to near-wall turbulence structures are summarised. Novel applications of DBD plasma actuators for aerodynamic control are then discussed, including pitch and roll control, plasma jet vectoring, circulation control and plasma flap, showing a potential of DBD plasma actuators for replacing movable, aircraft control surfaces. Finally, vortex shedding control techniques by a number of different plasma actuators are surveyed.

  11. SYLLABUS: PHYSICS 8120 PLASMA PHYSICS FALL 2007

    E-print Network

    Wiita, Paul J.

    SYLLABUS: PHYSICS 8120 PLASMA PHYSICS FALL 2007 Instructor: Prof. Paul J. Wiita Class Timings time. Required Text: Russell M. Kulsrud, Plasma Physics for Astrophysics (Princeton University Press A. Sturrock, Plasma Physics 3) Nicholas A. Krall & Alvin W. Trivelpiece, Principles of Plasma

  12. TOPICAL REVIEW: Thermal plasma waste treatment

    Microsoft Academic Search

    Joachim Heberlein; Anthony B. Murphy

    2008-01-01

    Plasma waste treatment has over the past decade become a more prominent technology because of the increasing problems with waste disposal and because of the realization of opportunities to generate valuable co-products. Plasma vitrification of hazardous slags has been a commercial technology for several years, and volume reduction of hazardous wastes using plasma processes is increasingly being used. Plasma gasification

  13. Plasma convection and line-tying

    Microsoft Academic Search

    S. Fornaca

    1983-01-01

    The directed motion of a low-? plasma across a toroidal magnetic field is examined as the degree of electrical contact between the plasma and a conducting end wall (line-tying) is varied in a controlled manner. Experimentally, little difference is found between the motion of a completely isolated plasma and that of a plasma in contact with a wall that does

  14. Plasma Processing of Metallic and Semiconductor Thin Films in the Fisk Plasma Source

    NASA Technical Reports Server (NTRS)

    Lampkin, Gregory; Thomas, Edward, Jr.; Watson, Michael; Wallace, Kent; Chen, Henry; Burger, Arnold

    1998-01-01

    The use of plasmas to process materials has become widespread throughout the semiconductor industry. Plasmas are used to modify the morphology and chemistry of surfaces. We report on initial plasma processing experiments using the Fisk Plasma Source. Metallic and semiconductor thin films deposited on a silicon substrate have been exposed to argon plasmas. Results of microscopy and chemical analyses of processed materials are presented.

  15. Plasma Glucose Lab Problems --Solutions 1 Bio390 Plasma Glucose Regulation Problems --Solutions

    E-print Network

    Prestwich, Ken

    Plasma Glucose Lab Problems -- Solutions 1 Bio390 Plasma Glucose Regulation Problems -- Solutions 1. Assume that a person ingests 50g of glucose and that all of it enters the blood and none is metabolized or excreted. Calculate the concentration (in mg glucose/dl plasma) in that person's plasma if: plasma

  16. Metal plasma immersion ion implantation and deposition using vacuum arc plasma sources

    Microsoft Academic Search

    André Anders; Simone Anders; Ian G. Brown; Michael R. Dickinson; Robert A. MacGill

    1994-01-01

    Plasma source ion implantation (PSII) with metal plasma results in a qualitatively different kind of surface modification than with gaseous plasma due to the condensable nature of the metal plasma, and a new, PSII-related technique can be defined: metal plasma immersion ion implantation and deposition (MPI). Tailored, high-quality films of any solid metal, metal alloy, or carbon (amorphous diamond) can

  17. CHAPTER 5. PLASMA DESCRIPTIONS I: KINETIC, TWO-FLUID 1 Plasma Descriptions I

    E-print Network

    Callen, James D.

    CHAPTER 5. PLASMA DESCRIPTIONS I: KINETIC, TWO-FLUID 1 Chapter 5 Plasma Descriptions I: Kinetic, Two-Fluid Descriptions of plasmas are obtained from extensions of the kinetic theory of gases of charged particles in the plasma, and because the electric and magnetic fields in the plasma must

  18. Phys780: Basic Plasma Physics 1 PHYS 780. Basic Plasma Physics

    E-print Network

    Phys780: Basic Plasma Physics 1 PHYS 780. Basic Plasma Physics Course objective The course objective is to introduce students to basic concepts of plasma physics and magneto theory of plasma. Vlasov equation. #12;Phys780: Basic Plasma Physics 2 9. October 1, Wednesday, Two

  19. Characterisation of plasma in a rail gun

    NASA Technical Reports Server (NTRS)

    Ray, P. K.

    1986-01-01

    The mechanism of plasma and projectile acceleration in a DC rail gun is described from a microscopic point of view through the establishment of the Hall field. The plasma conductivity is shown to be a tensor, indicating that there is a small component of current parallel to the direction of acceleration. The plasma characteristics are evaluated in the experiment of Bauer et. al., as a function of plasma mass through a simple fluid mechanical analysis of the plasma. By equating the energy dissipatated in the plasma with the radiation heat loss, the properties of the plasma are determined.

  20. Coherent control of plasma dynamics.

    PubMed

    He, Z-H; Hou, B; Lebailly, V; Nees, J A; Krushelnick, K; Thomas, A G R

    2015-01-01

    Coherent control of a system involves steering an interaction to a final coherent state by controlling the phase of an applied field. Plasmas support coherent wave structures that can be generated by intense laser fields. Here, we demonstrate the coherent control of plasma dynamics in a laser wakefield electron acceleration experiment. A genetic algorithm is implemented using a deformable mirror with the electron beam signal as feedback, which allows a heuristic search for the optimal wavefront under laser-plasma conditions that is not known a priori. We are able to improve both the electron beam charge and angular distribution by an order of magnitude. These improvements do not simply correlate with having the 'best' focal spot, as the highest quality vacuum focal spot produces a greatly inferior electron beam, but instead correspond to the particular laser phase front that steers the plasma wave to a final state with optimal accelerating fields. PMID:25975737

  1. Conductivity of a relativistic plasma

    SciTech Connect

    Braams, B.J.; Karney, C.F.F.

    1989-03-01

    The collision operator for a relativistic plasma is reformulated in terms of an expansion in spherical harmonics. This formulation is used to calculate the electrical conductivity. 13 refs., 1 fig., 1 tab.

  2. Mobile inductively coupled plasma system

    DOEpatents

    D'Silva, Arthur P. (Ames, IA); Jaselskis, Edward J. (Ames, IA)

    1999-03-30

    A system for sampling and analyzing a material located at a hazardous site. A laser located remote from the hazardous site is connected to an optical fiber, which directs laser radiation proximate the material at the hazardous site. The laser radiation abates a sample of the material. An inductively coupled plasma is located remotely from the material. An aerosol transport system carries the ablated particles to a plasma, where they are dissociated, atomized and excited to provide characteristic optical reduction of the elemental constituents of the sample. An optical spectrometer is located remotely from the site. A second optical fiber is connected to the optical spectrometer at one end and the plasma source at the other end to carry the optical radiation from the plasma source to the spectrometer.

  3. Laser Assisted Plasma Arc Welding

    SciTech Connect

    FUERSCHBACH,PHILLIP W.

    1999-10-05

    Experiments have been performed using a coaxial end-effecter to combine a focused laser beam and a plasma arc. The device employs a hollow tungsten electrode, a focusing lens, and conventional plasma arc torch nozzles to co-locate the focused beam and arc on the workpiece. Plasma arc nozzles were selected to protect the electrode from laser generated metal vapor. The project goal is to develop an improved fusion welding process that exhibits both absorption robustness and deep penetration for small scale (< 1.5 mm thickness) applications. On aluminum alloys 6061 and 6111, the hybrid process has been shown to eliminate hot cracking in the fusion zone. Fusion zone dimensions for both stainless steel and aluminum were found to be wider than characteristic laser welds, and deeper than characteristic plasma arc welds.

  4. Space Flight Plasma Data Analysis

    NASA Technical Reports Server (NTRS)

    Wright, Kenneth H.; Minow, Joseph I.

    2009-01-01

    This slide presentation reviews a method to analyze the plasma data that is reported on board the International Space station (ISS). The Floating Potential Measurement Unit (FPMU), the role of which is to obtain floating potential and ionosphere plasma measurements for validation of the ISS charging model, assess photo voltaic array variability and interpreting IRI predictions, is composed of four probes: Floating Potential Probe (FPP), Wide-sweep Langmuir Probe (WLP), Narrow-sweep Langmuir Probe (NLP) and the Plasma Impedance Probe (PIP). This gives redundant measurements of each parameter. There are also many 'boxes' that the data must pass through before being captured by the ground station, which leads to telemetry noise. Methods of analysis for the various signals from the different sets are reviewed. There is also a brief discussion of LP analysis of Low Earth Orbit plasma simulation source.

  5. Plasma in the Jovian magnetosphere

    NASA Technical Reports Server (NTRS)

    Goertz, C. K.

    1975-01-01

    It is shown that the plasma in Jupiter's ionosphere is collisionless above a certain level. In the outer magnetosphere, where the rotational force dominates the gravitational force, the collisionless plasma has a beam-like distribution and gives rise to a two-stream instability. This leads to trapping of plasma in the centrifugally dominated region of the magnetosphere. Plasma is lost by recombination. Equilibrium-trapped particle densities are calculated by requiring a balance between trapping by wave-particle interaction and loss by recombination. The results are compared with recent observations from Pioneer 10. It is suggested that the observations require an unexplained ion-heating mechanism. Some consequences of the model are discussed.

  6. Radioimmunoassay of corticotropin from plasma

    SciTech Connect

    Gutkowska, J.; Julesz, J.; St-Louis, J.; Genest, J.

    1982-11-01

    We describe a specific and highly sensitive radioimmunoassay for corticotropin (ACTH) in human plasma. As little as 1.9 pg of circulating ACTH can be detected per milliliter (0.44 pmol/L). ACTH is first extracted from plasma samples by adsorption onto pretreated Vycor glass powder, eluted from the adsorbent by acetone, and then lyophilized. For purification of /sup 125/I-labeled ACTH, a small octadecasilyl silica column is used. The mean (and SD) concentration of ACTH in plasma from 18 ostensibly normal subjects was 10.3 (4.3) pmol/L. After overnight suppression with dexamethasone in seven of these normal subjects, their ACTH values fell to 2.62 (1.3) pmol/L (p less than 0.0005). This assay will permit clinical evaluation of ACTH plasma concentrations in clinical investigation and of the effects of drug administration on circulating ACTH.

  7. Radioimmunoassay of corticotropin from plasma

    SciTech Connect

    Gutkowska, J.; Julesz, J.; St. Louis, J.; Genest, J.

    1982-01-01

    We describe a specific and highly sensitive radioimmunoassay for corticotropin (ACTH) in human plasma. As little as 1.9 pg of circulating ACTH can be detected per milliliter (0.44 pmol/L). ACTH is first extracted from plasma samples by adsorption onto pretreated Vycor glass powder, eluted from the adsorbant by acetone, and then lyophilized. For purification of /sup 125/I-labeled ACTH, a small octadecasilyl silica column is used. The mean (and SD) concentration of ACTH in plasma from 18 ostensibly normal subjects was 10.3 (4.3) pmol/L. After overnight suppression with dexamethasone in seven of these normal subjects, their ACTH values fell to 2.62 (1.3) pmol/L (p<0.0005). This assay will permit clinical evaluation of ACTH plasma concentrations in clinical investigation and of the effects of drug administration on circulating ACTH.

  8. Plasma Rain - Duration: 33 seconds.

    NASA Video Gallery

    On April 19, 2010 AIA observed one of the largest prominence eruptions in years. The huge structure erupts, but a great deal of the plasma (hundreds of millions of tons) is unable to escape the gra...

  9. The Wisconsin Plasma Astrophysics Laboratory

    E-print Network

    Forest, C B; Brookhart, M; Cooper, C M; Clark, M; Desangles, V; Egedal, J; Endrizzi, D; Miesch, M; Khalzov, I V; Li, H; Milhone, J; Nornberg, M; Olson, J; Peterson, E; Roesler, F; Schekochihin, A; Schmitz, O; Siller, R; Spitkovsky, A; Stemo, A; Wallace, J; Weisberg, D; Zweibel, E

    2015-01-01

    The Wisconsin Plasma Astrophysics Laboratory (WiPAL) is a flexible user facility designed to study a range of astrophysically relevant plasma processes as well as novel geometries which mimic astrophysical systems. A multi-cusp magnetic bucket constructed from strong samarium cobalt permanent magnets now confines a 10 m$^3$, fully ionized, magnetic-field free plasma in a spherical geometry. Plasma parameters of $ T_{e}\\approx5-20$ eV and $n_{e}\\approx10^{11}-5\\times10^{12}$ cm$^{-3}$ provide an ideal testbed for a range of astrophysical experiments including self-exciting dynamos, collisionless magnetic reconnection, jet stability, stellar winds, and more. This article describes the capabilities of WiPAL along with several experiments, in both operating and planning stages, that illustrate the range of possibilities for future users.

  10. Coherent control of plasma dynamics

    E-print Network

    He, Z -H; Lebailly, V; Nees, J A; Krushelnick, K; Thomas, A G R

    2015-01-01

    Coherent control of a system involves steering an interaction to a final coherent state by controlling the phase of an applied field. Plasmas support coherent wave structures that can be generated by intense laser fields. Here, we demonstrate the coherent control of plasma dynamics in a laser wakefield electron acceleration experiment. A genetic algorithm is implemented using a deformable mirror with the electron beam signal as feedback, which allows a heuristic search for the optimal wavefront under laser-plasma conditions that is not known a priori. We are able to improve both the electron beam charge and angular distribution by an order of magnitude. These improvements do not simply correlate with having the `best' focal spot, since the highest quality vacuum focal spot produces a greatly inferior electron beam, but instead correspond to the particular laser phase that steers the plasma wave to a final state with optimal accelerating fields.

  11. Plasma Heating: An Advanced Technology

    NASA Technical Reports Server (NTRS)

    1994-01-01

    The Mercury and Apollo spacecraft shields were designed to protect astronauts from high friction temperatures (well over 2,000 degrees Fahrenheit) when re-entering the Earth's atmosphere. It was necessary to test and verify the heat shield materials on Earth before space flight. After exhaustive research and testing, NASA decided to use plasma heating as a heat source. This technique involves passing a strong electric current through a rarefied gas to create a plasma (ionized gas) that produces an intensely hot flame. Although NASA did not invent the concept, its work expanded the market for commercial plasma heating systems. One company, Plasma Technology Corporation (PTC), was founded by a member of the team that developed the Re-entry Heating Simulator at Ames Research Center (ARC). Dr. Camacho, President of PTC, believes the technology has significant environmental applications. These include toxic waste disposal, hydrocarbon, decomposition, medical waste disposal, asbestos waste destruction, and chemical and radioactive waste disposal.

  12. Layered plasma polymer composite membranes

    DOEpatents

    Babcock, W.C.

    1994-10-11

    Layered plasma polymer composite fluid separation membranes are disclosed, which comprise alternating selective and permeable layers for a total of at least 2n layers, where n is [>=]2 and is the number of selective layers. 2 figs.

  13. MHD stability of tokamak plasmas

    SciTech Connect

    Chance, M.S. Sun, Y.C.; Jardin, S.C.; Kessel, C.E.; Okabayashi, M.

    1992-01-01

    This paper will give an overview of the some of the methods which are used to simulate the ideal MHD properties of tokamak plasmas. A great deal of the research in this field is necessarily numerical and the substantial progress made during the past several years has roughly paralleled the continuing availability of more advanced supercomputers. These have become essential to accurately model the complex configurations necessary for achieving MHD stable reactor grade conditions. Appropriate tokamak MHD equilibria will be described. Then the stability properties is discussed in some detail, emphasizing the difficulties of obtaining stable high {beta} discharges in plasmas in which the current is mainly ohmically driven and thus demonstrating the need for tailoring the current and pressure profiles of the plasma away from the ohmic state. The outline of this paper will roughly follow the physics development to attain the second region of stability in the PBX-M device at The Princeton Plasmas Physics Laboratory.

  14. Plasma transport near material boundaries

    SciTech Connect

    Singer, C.E.

    1985-06-01

    The fluid theory of two-dimensional (2-d) plasma transport in axisymmetric devices is reviewed. The forces which produce flow across the magnetic field in a collisional plasma are described. These flows may lead to up-down asymmetries in the poloidal rotation and radial fluxes. Emphasis is placed on understanding the conditions under which the known 2-d plasma fluid equations provide a valid description of these processes. Attempts to extend the fluid treatment to less collisional, turbulent plasmas are discussed. A reduction to the 1-d fluid equations used in many computer simulations is possible when sources or boundary conditions provide a large enough radial scale length. The complete 1-d fluid equations are given in the text, and 2-d fluid equations are given in the Appendix.

  15. Experiment of THz transmission through plasma

    NASA Astrophysics Data System (ADS)

    Sun, Jinhai; Gallacher, Jordan; Issac, Riju; Huang, Zhixun; Jaroszynski, Dino

    2014-12-01

    Research on terahertz wave transmission through plasma is significant for researches on plasma itself and transmission discipline of terahertz wave through plasma. It is possible for plasma with suitable density to be an available stealth outerwear for plane or missile in THz waveband. In this paper, plasma is gotten by ionizing inert gases such as argon and helium gases with pulsed high alternating voltage. With electro-optic pump-probe measurement, THz transmission phenomena through plasma have been studied. The experiments show that some parts of THz frequency components have been cut off by plasma, and with the density of plasma rising, the starting frequency of THz prohibited by plasma is going higher. Experiments also provide an assistant scheme for plasma diagnose with terahertz technique.

  16. Dusty-Plasma Particle Accelerator

    NASA Technical Reports Server (NTRS)

    Foster, John E.

    2005-01-01

    A dusty-plasma apparatus is being investigated as means of accelerating nanometer- and micrometer-sized particles. Applications for the dusty-plasma particle accelerators fall into two classes: Simulation of a variety of rapidly moving dust particles and micrometeoroids in outer-space environments that include micrometeoroid streams, comet tails, planetary rings, and nebulae and Deposition or implantation of nanoparticles on substrates for diverse industrial purposes that could include hardening, increasing thermal insulation, altering optical properties, and/or increasing permittivities of substrate materials. Relative to prior apparatuses used for similar applications, dusty-plasma particle accelerators offer such potential advantages as smaller size, lower cost, less complexity, and increased particle flux densities. A dusty-plasma particle accelerator exploits the fact that an isolated particle immersed in plasma acquires a net electric charge that depends on the relative mobilities of electrons and ions. Typically, a particle that is immersed in a low-temperature, partially ionized gas, wherein the average kinetic energy of electrons exceeds that of ions, causes the particle to become negatively charged. The particle can then be accelerated by applying an appropriate electric field. A dusty-plasma particle accelerator (see figure) includes a plasma source such as a radio-frequency induction discharge apparatus containing (1) a shallow cup with a biasable electrode to hold the particles to be accelerated and (2) a holder for the substrate on which the particles are to impinge. Depending on the specific design, a pair of electrostatic-acceleration grids between the substrate and discharge plasma can be used to both collimate and further accelerate particles exiting the particle holder. Once exposed to the discharge plasma, the particles in the cup quickly acquire a negative charge. Application of a negative voltage pulse to the biasable electrode results in the initiation of a low-current, high-voltage cathode spot. Plasma pressure associated with the cathode spot as well as the large voltage drop at the cathode spot accelerates the charged particles toward the substrate. The ultimate kinetic energy attained by particles exiting the particle holder depends in part on the magnitude of the cathode spot sheath potential difference, which is proportional to the magnitude of the voltage pulse, and the on the electric charge on the dust. The magnitude of the voltage pulse can be controlled directly, whereas the particle s electric charge can be controlled indirectly by controlling the operating parameters of the plasma apparatus.

  17. Chaos in a complex plasma

    SciTech Connect

    Sheridan, T.E. [Department of Physics and Astronomy, Ohio Northern University, Ada, Ohio 45810 (United States)

    2005-08-15

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

  18. Plasma vitrification of fly ash

    SciTech Connect

    Beudin, V.; Guihard, B.; Pineau, D.; Labrot, M.; Soler, G.; Favier, J.M.; Boudeau, A.

    1995-12-31

    This paper presents the plasma vitrification of fly-ash produced by a Municipal Waste Incinerator, as programmed by Europlasma Company in France. It describes the main assumptions, technical and economical data and regulations taken into account to build and operate the first industrial pilot plant from 1995, near Bordeaux (France), using a non transferred plasma torch of 500 kW operated with air.

  19. Inertial currents in isotropic plasma

    NASA Technical Reports Server (NTRS)

    Heinemann, M.; Erickson, G. M.; Pontius, D. H., Jr.

    1994-01-01

    The magnetospheric convection electric field contributes to Birkeland currents. The effects of the field are to polarize the plasma by displacing the bounce paths of the ions from those of electrons, to redistribute the pressure so that it is not constant along magnetic field lines, and to enhance the pressure gradient by the gradient of the bulk speed. Changes in the polarization charge during the convection of the plasma are neutralized by electrons in the form of field-aligned currents that close through the ionosphere. The pressure drives field-aligned currents through its gradient in the same manner as in quasi-static plasmas, but with modifications that are important if the bulk speed is of the order of the ion thermal speed; the variations in the pressure along field lines are maintained by a weak parallel potential drop. These effects are described in terms of the field-aligned currents in steady state, isotropic, MHD plasma. Solutions are developed by taking the MHD limit ot two-fluid solutions and illustrated in the special case of Maxwellian plasma for which the temperature is constant along magnetic field lines. The expression for the Birkeland current density is a generalization of Vasyliunas' expression for the field-aligned current density in quasi-static plasma and provides a unifying expression when both pressure gradients and ion inertia operate simultaneously as sources of field-aligned currents. It contains a full account of different aspects of the ion flow (parallel and perpendicular velocity and vorticity) that contribute to the currents. Contributions of ion inertia to field-aligned currents will occur in regions of strong velocity shear, electric field reversal, or large gradients in the parallel velocity or number density, and may be important in the low-latitude boundary layer, plasma sheet boundary layer, and the inner edge region of the plasma sheet.

  20. How a Plasma Etcher Works

    NSDL National Science Digital Library

    This website includes an animation which illustrates how a Plasma Etcher works. Objective: Describe all the steps used to load, etch, and unload a wafer from a plasma etcher. This simulation is from Module 048 of the Process & Equipment II Cluster of the MATEC Module Library (MML). You can find this animation under the section "Process & Equipment II." To view other clusters or for more information about the MML visit http://matec.org/ps/library3/process_I.shtmlKey

  1. Plasma disruption modeling and simulation

    SciTech Connect

    Hassanein, A.

    1994-07-01

    Disruptions in tokamak reactors are considered a limiting factor to successful operation and a reliable design. The behavior of plasma-facing components during a disruption is critical to the overall integrity of the reactor. Erosion of plasma facing-material (PFM) surfaces due to thermal energy dump during the disruption can severely limit the lifetime of these components and thus diminish the economic feasibility of the reactor.Initially, the incident plasma particles will deposit their energy directly on the PFM surface, heating it to a very high temperature where ablation occurs. Models for plasma-material interactions have been developed and used to predict material thermal evolution during the disruption. Within a few microseconds after the start of the disruption, enough material is vaporized to intercept most of the incoming plasma particles. Models for plasma-vapor interactions are necessary to predict vapor cloud expansion and hydrodynamics. Continuous heating of the vapor cloud above the material surface by the incident plasma particles will excite, ionize, and cause vapor atoms to emit thermal radiation. Accurate models for radiation transport in the vapor are essential for calculating the net radiated flux to the material surface which determines the final erosion thickness and consequently component lifetime. A comprehensive model that takes into account various stages of plasma-material interaction has been developed and used to predict erosion rates during reactor disruption, as well during induced disruption in laboratory experiments. Differences between various simulation experiments and reactor conditions are discussed. A two-dimensional radiation transport model has been developed to particularly simulate the effect of small test samples used in laboratory disruption experiments.

  2. Plasma disruption modeling and simulation

    SciTech Connect

    Hassanein, A. [Argonne National Lab., IL (United States)

    1994-11-01

    Disruptions in tokamak reactors are considered a limiting factor to successful operation and reliable design. The behavior of plasma-facing components during a disruption is critical to the overall integrity of the reactor. Erosion of plasma facing-material (PFM) surfaces due to thermal energy dump during the disruption can severely limit the lifetime of these components and thus diminish the economic feasibility of the reactor. A comprehensive understanding of the interplay of various physical processes during a disruption is essential for determining component lifetime and potentially improving the performance of such components. There are three principal stages in modeling the behavior of PFM during a disruption. Initially, the incident plasma particles will deposit their energy directly on the PFM surface, heating it to a very high temperature where ablation occurs. Models for plasma-material interactions have been developed and used to predict material thermal evolution during the disruption. Within a few microseconds after the start of the disruption, enough material is vaporized to intercept most of the incoming plasma particles. Models for plasma-vapor interactions are necessary to predict vapor cloud expansion and hydrodynamics. Continuous heating of the vapor cloud above the material surface by the incident plasma particles will excite, ionize, and cause vapor atoms to emit thermal radiation. Accurate models for radiation transport in the vapor are essential for calculating the net radiated flux to the material surface which determines the final erosion thickness and consequently component lifetime. A comprehensive model that takes into account various stages of plasma-material interaction has been developed and used to predict erosion rates during reactor disruption, as well during induced disruption in laboratory experiments.

  3. Laboratory experiments in dusty plasmas

    Microsoft Academic Search

    R. L. Merlino; A. Barkan; N. D’Angelo; W. Xu; B. Song

    1995-01-01

    We describe a rotating-drum dust-dispersal device, which we have used in conjunction with an existing Q machine, to produce extended, steady-state, magnetized dusty plasma columns. This device is capable of generating dusty plasmas in which as much as ?90% of the negative charge is attached to dust grains of 1–10 ?m size with dust densities up to ?104 cm?3. Langmuir

  4. Plasma propulsion for interplanetary flight

    Microsoft Academic Search

    Franklin R. Chang-Díaz

    2006-01-01

    The Variable Specific Impulse Magnetoplasma Rocket (VASIMR) is a high-power propulsion concept using radio waves to create and accelerate plasma in a magnetic nozzle. Important features are its high and variable exhaust velocity, which greatly enhances performance. A NASA-led, research team is developing this technology in the U.S. Recent advances include demonstration of efficient propellant utilization in its helicon plasma

  5. NADH oxidase of plasma membranes

    Microsoft Academic Search

    D. James Morré; Andrew O. Brightman

    1991-01-01

    NADH oxidase is a cyanide-resistant and hormone-responsive oxidase intrinsic to the plasma membrane of both plant and animal cells. The activity has many unique characteristics that distinguish it from other oxidases and oxidoreductases of both organelles and internal membranes and from other oxidoreductases of the plasma membrane. Among these are resistance to inhibition by cyanide, catalase, superoxide dismutase, and phenylchloromer-curibenzoate.

  6. Flavors in an expanding plasma

    E-print Network

    Johannes Große; Romuald A. Janik; Piotr Surówka

    2008-02-05

    We consider the effect of an expanding plasma on probe matter by determining time-dependent D7 embeddings in the holographic dual of an expanding viscous plasma. We calculate the chiral condensate and meson spectra including contributions of viscosity. The chiral condensate essentially confirms the expectation from the static black hole. For the meson spectra we propose a scheme that is in agreement with the adiabatic approximation. New contributions arise for the vector mesons at the order of the viscosity terms.

  7. Neutrino dispersion in magnetized plasma

    E-print Network

    N. V. Mikheev; E. N. Narynskaya

    2008-12-02

    The neutrino dispersion in the charge symmetric magnetized plasma is investigated. We have studied the plasma contribution into the additional energy of neutrino and obtained the simple expression for it. We consider in detail the neutrino self-energy under physical conditions of weak field, moderate field and strong field limits. It is shown that our result for neutrino dispersion in moderate magnetic field differ substantially from the previous one in the literature.

  8. Plasma-Broadened Cesium Lines

    Microsoft Academic Search

    Philip M. Stone; Lewis Agnew

    1962-01-01

    Profiles of isolated plasma-broadened lines have been calculated and measured for the fundamental series (5D-nF) of cesium. The calculations used the static theory for the ion interactions and the classical path, nonadiabatic impact approximation for the electron interactions. The necessary matrix elements have been obtained from wave functions specially determined for this purpose. The calculations were made for plasma ion

  9. Introduction to laser plasma diagnostics

    Microsoft Academic Search

    A. A. Hauer; H. A. Baldis

    1988-01-01

    This report reviews optical and X-ray techniques for the diagnosis of laser-produced plasmas. Emphasis is placed on the parameter regimes (e.g., laser irradiance greater than 10 to the 12th power watts\\/sq cm) appropriate to the laser fusion field. We also include, however, material related to other laser-plasma work such as chemical analysis. This work is intended to be an introduction

  10. Fusion plasma theory project summaries

    NASA Astrophysics Data System (ADS)

    1993-10-01

    This Project Summary book is a published compilation consisting of short descriptions of each project supported by the Fusion Plasma Theory and Computing Group of the Advanced Physics and Technology Division of the Department of Energy, Office of Fusion Energy. The summaries contained in this volume were written by the individual contractors with minimal editing by the Office of Fusion Energy. Previous summaries were published in February of 1982 and December of 1987. The Plasma Theory program is responsible for the development of concepts and models that describe and predict the behavior of a magnetically confined plasma. Emphasis is given to the modelling and understanding of the processes controlling transport of energy and particles in a toroidal plasma and supporting the design of the International Thermonuclear Experimental Reactor (ITER). A tokamak transport initiative was begun in 1989 to improve understanding of how energy and particles are lost from the plasma by mechanisms that transport them across field lines. The Plasma Theory program has actively participated in this initiative. Recently, increased attention has been given to issues of importance to the proposed Tokamak Physics Experiment (TPX). Particular attention has been paid to containment and thermalization of fast alpha particles produced in a burning fusion plasma as well as control of sawteeth, current drive, impurity control, and design of improved auxiliary heating. In addition, general models of plasma behavior are developed from physics features common to different confinement geometries. This work uses both analytical and numerical techniques. The Fusion Theory program supports research projects at U.S. government laboratories, universities and industrial contractors. Its support of theoretical work at universities contributes to the office of Fusion Energy mission of training scientific manpower for the U.S. Fusion Energy Program.

  11. Plasma core reactor applications

    NASA Technical Reports Server (NTRS)

    Latham, T. S.; Rodgers, R. J.

    1976-01-01

    Analytical and experimental investigations were conducted to demonstrate the feasibility of fissioning uranium plasma core reactors and to characterize space and terrestrial applications for such reactors. Uranium hexafluoride fuel is injected into core cavities and confined away from the surface by argon buffer gas injected tangentially from the peripheral walls. Radiant heat transfer calculations were performed for a six-cavity reactor configuration. Axial working fluid channels are located along a fraction of each cavity peripheral wall. Results of calculations for outward-directed radiant energy fluxes corresponding to radiating temperatures of 2000 to 5000 K indicate total operating pressures from 80 to 650 atm, centerline temperatures from 6900 to 30,000 K, and total radiated powers from 25 to 2500 MW, respectively. Applications are described for this type of reactor such as (1) high-thrust, high specific impulse space propulsion, (2) highly efficient systems for generation of electricity, and (3) hydrogen or synthetic fuel production systems using the intense radiant energy fluxes.

  12. Undamped electrostatic plasma waves

    E-print Network

    Valentini, F; Califano, F; Pegoraro, F; Veltri, P; Morrison, P J; O'Neil, T M

    2015-01-01

    Electrostatic waves in a collision-free unmagnetized plasma of electrons with fixed ions are investigated for electron equilibrium velocity distribution functions that deviate slightly from Maxwellian. Of interest are undamped waves that are the small amplitude limit of nonlinear excitations, such as electron acoustic waves (EAWs). A deviation consisting of a small plateau, a region with zero velocity derivative over a width that is a very small fraction of the electron thermal speed, is shown to give rise to new undamped modes, which here are named {\\it corner modes}. The presence of the plateau turns off Landau damping and allows oscillations with phase speeds within the plateau. These undamped waves are obtained in a wide region of the $(k,\\omega_{_R})$ plane ($\\omega_{_R}$ being the real part of the wave frequency and $k$ the wavenumber), away from the well-known `thumb curve' for Langmuir waves and EAWs based on the Maxwellian. Results of nonlinear Vlasov-Poisson simulations that corroborate the existenc...

  13. Compact plasma accelerator

    NASA Technical Reports Server (NTRS)

    Foster, John E. (Inventor)

    2004-01-01

    A compact plasma accelerator having components including a cathode electron source, an anodic ionizing gas source, and a magnetic field that is cusped. The components are held by an electrically insulating body having a central axis, a top axial end, and a bottom axial end. The cusped magnetic field is formed by a cylindrical magnet having an axis of rotation that is the same as the axis of rotation of the insulating body, and magnetized with opposite poles at its two axial ends; and an annular magnet coaxially surrounding the cylindrical magnet, magnetized with opposite poles at its two axial ends such that a top axial end has a magnetic polarity that is opposite to the magnetic polarity of a top axial end of the cylindrical magnet. The ionizing gas source is a tubular plenum that has been curved into a substantially annular shape, positioned above the top axial end of the annular magnet such that the plenum is centered in a ring-shaped cusp of the magnetic field generated by the magnets. The plenum has one or more capillary-like orifices spaced around its top such that an ionizing gas supplied through the plenum is sprayed through the one or more orifices. The plenum is electrically conductive and is positively charged relative to the cathode electron source such that the plenum functions as the anode; and the cathode is positioned above and radially outward relative to the plenum.

  14. Plasma interactions monitoring system

    NASA Technical Reports Server (NTRS)

    Roberts, William T.

    1988-01-01

    The plasma environment around the space station is expected to be different from that environment which occurs naturally at these altitudes because of the unprecedented size of the space station, its orbital motion, and its high power distribution system. Although there are models which predict the environment around the station, they do not take into account changes in configuration, changes in the natural and induced environments, nor interactions between the different environments. There will be unique perturbations associated with the space station, which will vary as the space station is being developed. Even after the developed space station has been completed environmental conditions will change as the payloads are changed and as the station systems and materials undergo degradation and modification. Because the space station will be a point of many varied activities the environment will continually undergo perturbations from effluents resulting from operations of the reboost module, EVA, airlock operations, and vacuum venting. The use of the Mobile Service Center will cause disturbances which cannot, at this time, be predicted. Also, the natural environment will be affected by solar flares. In addition, the operations of attached payloads, (e.g., ASTROMAG) themselves will undoubtedly cause perturbations to the ambient environment. Finally, the natural environment will change as a result of natural perturbations such as solar flares and geomagnetic storms.

  15. Plasma pinchlamp surface preparation

    NASA Astrophysics Data System (ADS)

    Asmus, John F.

    1997-09-01

    A high-pressure laser-guided gas-embedded plasma pinchlamp is described for the generation of intense UV radiation. It has been configured to optimize energy transfer from the storage PFN. The output energy peaks within the spectral range 150 - 250 nm with a pulsed power of 20 MW at 10 Hz. The device employs a working gas of argon at 3 AMAGAT and has a pulsewidth of 20 microseconds. The results of exploratory surface modification experiments with the pinchlamp are reported. These include the destruction of chemical warfare agent simulants, asbestos, petroleum, and insecticides on surfaces as well as semiconductor annealing. In addition it was determined that various aircraft coatings are able to be removed from aluminum and composite substrates. These coatings included primers, top coats, and anti-erosion materials. This pinchlamp technology potentially fills a performance gap in the hard ultraviolet between flashlamps and lasers. On the one hand it offers a peak power and brightness comparable to parameters customarily associated with laser technology. On the other hand it possesses the efficiency, simplicity, and scalability often encountered with conventional flashlamp systems.

  16. Modeling thermal plasma material processing experiments

    NASA Astrophysics Data System (ADS)

    Varacalle, D. J., Jr.; Richardson, L. S.; McIlwain, M. E.

    Spatial distributions of plasma variables (concentration, temperature, and velocity) were calculated for alumina and carbon species injected in an argon thermal plasma. The plasma behavior was modeled from arc initiation through free plume expansion by combining a plasma code with a plume code. The model assumed a direct current, constrictor type, arc heater. The feasibility of using thermal plasmas for ore reduction was analyzed. The process investigated the carbothermic reduction of alumina.

  17. Experimental investigation of plasma stream injection

    Microsoft Academic Search

    Huang Chaosong; Ren Zhaoxing

    1989-01-01

    Experimental investigation of plasma stream injection into a simple mirror device has been performed. The parameters of the plasma stream are determined. The electron temperature is 4 eV, the velocity of the stream is about 5\\/times\\/10⁶ cm\\/s. The plasma density and plasma current reach 10¹⁴ cm\\/sup \\/minus\\/3\\/ and 450 A, respectively. The plasma trapped in the mirror device drives an

  18. Plasma Ramparts Using Metastable Molecules

    NASA Astrophysics Data System (ADS)

    Rich, Joseph W.; Miles, Richard B.

    2002-10-01

    The main goals of this experimental and theoretical project were to demonstrate the ability to create a uniform and diffuse nonequilibrium air plasma at atmospheric pressure, with an electron density of 10(13) cm(-3), a temperature below 2000 K, scalable to cubic meter size, with a low power budget. The Ohio State Consortium was focusing on use of efficient ionization sources, specifically e-beams and short pulse ionization wave generators, and on mitigation of electron removal by using laser energy addition to excite the vibrational modes of the air species. By this means, the power budget to sustain a stable plasma in low temperature, atmospheric pressure air is significantly reduced.The plasma decay time has been increased by more than two orders of magnitude. In addition, there have been major efforts to investigate the relevant ionization, electron removal, and energy transfer processes in such air plasmas, to model and analyze both e-beam and short pulse ionization sources in large volume air plasmas, to develop short pulse ionization wave generators, and to develop and employ advanced diagnostic methods to characterize the air plasmas produced. There have been major positive and novel results achieved in each of these areas.

  19. Spectroscopic diagnostics of dusty plasmas

    NASA Astrophysics Data System (ADS)

    Ouaras, Karim

    2014-10-01

    The formation of carbon nanoparticles particles in low pressure magnetized hydrocarbon plasmas is investigated using infrared quantum cascade laser absorption spectroscopy (QCLAS), mass spectrometry (MS) and laser extinction spectroscopy (LES). Results showed that dust formation is correlated to the presence of a large amount of large positively charged hydrocarbon ions. Large negative ions or neutral species were not observed. These results, along with a qualitative comparison of diffusion and reaction characteristic, suggest that a positive ion may contribute to the growth of nanoparticles in hydrocarbon magnetized plasmas. Growth of carbon nanoparticles has been widely studied in RF plasma. Our aim is to complete these studies in different discharge system, in which the growth mechanisms may be different. In particular, we focus our work on dipolar ECR microwave discharge. The magnetic field of the plasma source is likely to trap carbon-containing charged particles and then modify the dust growth kinetics. In the present study the combination of these diagnostics gives us the tools to study the kinetics of plasma processes. In this way both qualitative and quantitative characteristics could be obtained. An outstanding role may be attributed to the positive ions in the monitored magnetized plasmas, whereas usually formation of dust is supposed driven by negative ions. In addition, we focus our work in tungsten nanoparticle in particular with LES, this noninvasive technique provide us the tool to follow the dynamics and concentration dust. K. Ouaras, L. Colina Delacqua, G. Lombardi, K. Hassouni, and X. Bonnin.

  20. Antimicrobial outcomes in plasma medicine

    NASA Astrophysics Data System (ADS)

    Ryan, Thomas P.; Stalder, Kenneth R.; Woloszko, Jean

    2015-03-01

    Plasma is referred to as the fourth state of matter and is frequently generated in the environment of a strong electric field. The result consists of highly reactive species--ions, electrons, reactive atoms and molecules, and UV radiation. Plasma Medicine unites a number of fields, including Physics, Plasma Chemistry, Cell Biology, Biochemistry, and Medicine. The treatment modality utilizes Cold Atmospheric Plasma (CAP), which is able to sterilize and treat microbes in a nonthermal manner. These gas-based plasma systems operate at close to room temperature and atmospheric pressure, making them very practical for a range of potential treatments and are highly portable for clinical use throughout the health care system. The hypothesis is that gas based plasma kills bacteria, fungus, and viruses but spares mammalian cells. This paper will review systematic work which shows examples of systems and performance in regards to antimicrobial effects and the sparing of mammalian cells. The mechanism of action will be discussed, as well as dosing for the treatment of microbial targets, including sterilization processes, another important healthcare need. In addition, commercial systems will be overviewed and compared, along with evidence-based, patient results. The range of treatments cover wound treatment and biofilms, as well as antimicrobial treatment, with little chance for resistance and tolerance, as in drug regimens. Current clinical studies include applications in dentistry, food treatment, cancer treatment, wound treatment for bacteria and biofilms, and systems to combat health care related infections.

  1. Electric field divertor plasma pump

    DOEpatents

    Schaffer, Michael J. (San Diego, CA)

    1994-01-01

    An electric field plasma pump includes a toroidal ring bias electrode (56) positioned near the divertor strike point of a poloidal divertor of a tokamak (20), or similar plasma-confining apparatus. For optimum plasma pumping, the separatrix (40) of the poloidal divertor contacts the ring electrode (56), which then also acts as a divertor plate. A plenum (54) or other duct near the electrode (56) includes an entrance aperture open to receive electrically-driven plasma. The electrode (56) is insulated laterally with insulators (63,64), one of which (64) is positioned opposite the electrode at the entrance aperture. An electric field E is established between the ring electrode (56) and a vacuum vessel wall (22), with the polarity of the bias applied to the electrode being relative to the vessel wall selected such that the resultant electric field E interacts with the magnetic field B already existing in the tokamak to create an E.times.B/B.sup.2 drift velocity that drives plasma into the entrance aperture. The pumped plasma flow into the entrance aperture is insensitive to variations, intentional or otherwise, of the pump and divertor geometry. Pressure buildups in the plenum or duct connected to the entrance aperture in excess of 10 mtorr are achievable.

  2. BOOK REVIEW: Kinetic theory of plasma waves, homogeneous plasmas

    NASA Astrophysics Data System (ADS)

    Porkolab, Miklos

    1998-11-01

    The linear theory of plasma waves in homogeneous plasma is arguably the most mature and best understood branch of plasma physics. Given the recently revised version of Stix's excellent Waves in Plasmas (1992), one might ask whether another book on this subject is necessary only a few years later. The answer lies in the scope of this volume; it is somewhat more detailed in certain topics than, and complementary in many fusion research relevant areas to, Stix's book. (I am restricting these comments to the homogeneous plasma theory only, since the author promises a second volume on wave propagation in inhomogeneous plasmas.) This book is also much more of a theorist's approach to waves in plasmas, with the aim of developing the subject within the logical framework of kinetic theory. This may indeed be pleasing to the expert and to the specialist, but may be too difficult to the graduate student as an `introduction' to the subject (which the author explicitly states in the Preface). On the other hand, it may be entirely appropriate for a second course on plasma waves, after the student has mastered fluid theory and an introductory kinetic treatment of waves in a hot magnetized `Vlasov' plasma. For teaching purposes, my personal preference is to review the cold plasma wave treatment using the unified Stix formalism and notation (which the author wisely adopts in the present book, but only in Chapter 5). Such an approach allows one to deal with CMA diagrams early on, as well as to provide a framework to discuss electromagnetic wave propagation and accessibility in inhomogeneous plasmas (for which the cold plasma wave treatment is perfectly adequate). Such an approach does lack some of the rigour, however, that the author achieves with the present approach. As the author correctly shows, the fluid theory treatment of waves follows logically from kinetic theory in the cold plasma limit. I only question the pedagogical value of this approach. Otherwise, I welcome this addition to the literature, for it gives the teacher of the subject a valuable reference where the inquisitive student will be able to read up on and satisfy himself about the practicality and reliability of the Vlasov theory in a hot magnetized and collisionless plasma. The book has excellent treatments of several new topics not included in previous textbooks, for example, the relativistic theory of plasma wave propagation, so important in electron cyclotron heating of magnetically confined fusion plasmas, a discussion of current drive theory and there is a welcome introduction to parametric instabilities in the final chapter. There are some things that make the readability of the book somewhat difficult. In the early parts, certain advanced concepts are introduced without much motivation or explanation, although the author is trying to be helpful by providing a list of relevant references at the end of each chapter. Here the teacher's role will be critical. Again, a certain amount of previous knowledge of the subject would prove to be invaluable to the student. The main content of the book is included in 11 chapters. Use is made of CGS Gaussian units, a favourite of plasma theorists. As the author states, these are still widely used in advanced plasma theory, and the student is well advised to become familiar with this system of units (as well as the SI system for applications). To help the reader in the Introduction, the author defines various expressions often used in plasma physics in practical units (frequencies in hertz, lengths in centimetres, temperatures in kiloelectronvolts and magnetic fields in teslas). Chapter 2 is entitled `Plasma Electrodynamics' and it introduces the Maxwell-Vlasov set of equations, as well as the important fundamentals of wave propagation, such as polarization, dispersion and the dielectric tensor, and energy relations. In Chapter 3, `Elementary Plasma Kinetic Theory', the author derives the Vlasov equation and the Fokker-Planck equation from the BBGKY hierarchy. This is a somewhat unusual chapter in a book on plasma waves, but I

  3. Influence of anomalous thermal losses of ignition conditions

    SciTech Connect

    Coppi, B.; Tang, W.M.

    1986-05-01

    In the process of achieving ignition conditions, it is likely that microinstabilities, which lead to anomalous thermal transport of the fusing nuclei, will be present. When such phenomena are taken into account, an appropriate formulation of ignition criteria becomes necessary. In particular, a new type of plasma density limit is identified.

  4. Simulation studies of anomalous slowing down of fusion products

    Microsoft Academic Search

    W. R. Sutton; C. K. Choi; G. H. Miley

    1982-01-01

    Future fusion reactors will rely on fusion product heating of the plasma for ignited (or near-ignited) operation. One factor that could drastically change such operation would be if the fusion product alpha initiates microinstabilities during slowing down. In addition to changing heating rates, this can result in a preferential transfer of energy to fuel ions as the alphas slow down

  5. Transport Studies in Highly Radiative Plasmas in TFTR

    NASA Astrophysics Data System (ADS)

    Hill, K. W.; Bell, M. G.; Bell, R. E.; Budny, R.; Ernst, D. R.; Mikkelsen, D. R.; Park, H. K.; Ramsey, A. T.; Rewoldt, G.; Synakowski, E. J.; Taylor, G.; Zarnstorff, M. C.; Bush, C. E.; Scott, S. D.

    1999-11-01

    Krypton and xenon puffing were used to reduce the limiter power loading and to study local transport in TFTR supershots. At NBI power Pb = 16 MW the core \\chie did not change, but \\chii and \\chi_? decreased significantly. At Pb > 28 MW carbon blooms were eliminated, and confinement and fusion power improved significantly. With Xe puffing the carbon poloidal velocity near the edge tripled, resulting in a factor of two increase in local Er and increased shearing rate. A comparison of microinstability growth rate calculations, using the FULL code, with the E×B shearing rate suggested that the ITG mode was unstable prior to Kr puffing, but was stabilized by the Kr puff. The MIST impurity transport code underestimated the radiated power from Kr and Xe by a factor of ~3, consistent with other tokamak measurements at lower temperature, and with EBIT measurements, which show a factor of 2 enhancement of radiated power from Kr at Te = 4.7 keV over MIST predictions.

  6. Plasma waves in parametric interactions

    NASA Astrophysics Data System (ADS)

    Yampolsky, Nikolai Andreevich

    The nonlinear laser-plasma interaction is widely discussed in the modern plasma literature with applications to inertial confinement fusion, generation of fast electrons, and amplification of high power radiation. Among nonlinear wave phenomena in plasma, the parametric wave coupling often plays the dominant role in laser-plasma interaction at moderate laser intensities since it is the lowest order nonlinear effect. The plasma wave can mediate the parametric laser coupling with high efficiency. We study the interplay of the parametric laser-plasma interaction and other physical effects which may affect this interaction. We study this interplay with an emphasis on the plasma-based backward Raman amplifier (BRA) based on the three-wave coupling. Three major types of physical effects in the parametric wave coupling are studied. In the first part of the thesis, we find the longitudinal profiles of the interacting waves in cases of interest for pulse compression. We find the solution for the output pulse in backward Raman amplification seeded by a laser pulse of finite duration. We also propose a new scheme for high-power amplification for pulses in the terahertz frequency range. For this scheme, based on the four-wave mixing in a capillary filled with plasma, we find the profile of the output pulse. The second part of this thesis is devoted to transverse effects, which may reduce the focusability of the output pulse in backward Raman amplification. We find that the transverse modulations of the pump can be averaged and do not reduce the amplified pulse focusability if the longitudinal length of these modulations is much smaller than the amplification length. In the third part, we study the kinetic effects. We propose a simplified fluid model for the nonlinear Landau damping of a parametrically driven plasma wave and study the effect of nonlinear Landau damping in backward Raman amplification. This simplified model can be useful not only for understanding complex phenomena, but also for making more complex problems tractable numerically. Finally, we analyze current experimental data and indicate limiting mechanisms in plasma-based backward Raman amplifier.

  7. Wireless communication capability of a reconfigurable plasma antenna

    Microsoft Academic Search

    Rajneesh Kumar; Dhiraj Bora

    2011-01-01

    A 30 cm long plasma column is excited by a surface wave, which acts as a plasma antenna. Using plasma properties (pattern formation\\/striations in plasmas) single plasma antenna can be transformed into array, helical, and spiral plasma antenna. Experiments are carried out to study the power patterns, directivity, and half power beam width of such different plasma antennas. Moreover, field

  8. Maxwell Prize Session: Hot Plasma Effects in Gas Discharge Plasma

    NASA Astrophysics Data System (ADS)

    Godyak, Valery

    2004-11-01

    Radio frequency (rf) gas discharges have been known for over a century. Recently, interest in low-pressure rf discharges has been revitalized due to great achievements and expectations in using such devices in plasma processing for manufacturing of semiconductor chips and lighting technology. In rf discharges the dominant interaction of the electromagnetic field with the plasma, and thus rf power absorption, takes place in the plasma boundary layer (near the electrode sheath in a capacitive and in the skin layer in an inductive rf discharge). The interaction of the electromagnetic field with plasma can be of local or nonlocal character. In the first case, there is local coupling between the rf current and the electric field described by a local complex conductivity tensor of a cold plasma. That corresponds to traditional (collisional) gas discharge physics. In the second case, electron thermal motion brings spatial dispersion into the relation between the rf current and the electric field, so that the conductivity tensor becomes a nonlocal operator. Stochastic (collisionless) electron heating, anomalous skin effect and a variety of plasma kinetic and nonlinear effects are typical for low-pressure rf discharges operating in the regime of nonlocal electrodynamics. Such phenomena are characteristic of hot fusion and space plasmas, where they are usually observed experimentally as some global effects. The ability to reproduce these phenomena in a table-top rf discharge experiment (equipped with spatially resolved electron kinetic and electromagnetic field diagnostics) makes the rf discharge a unique playground for basic plasma studies highly amenable to theoretical analysis. The subject of this talk is a review of nonlocal and nonlinear effects found in rf discharge experiments and theoretical analysis, where the interaction of electromagnetic field with plasma is controlled by the electron thermal motion rather than the electron-atom collisions. New features in the electron energy distribution, wave phase bifurcation and phase velocity reversal, collisionless and negative power absorption, harmonic generation and ponderomotive effect are found in these experiments and interpreted in terms of non-local, hot electron electrodynamics.

  9. Characteristics of plasma properties in an ablative pulsed plasma thruster

    SciTech Connect

    Schoenherr, Tony; Nees, Frank; Arakawa, Yoshihiro [Department of Aeronautics and Astronautics, University of Tokyo, Bunkyo, Tokyo 113-8656 (Japan); Komurasaki, Kimiya [Department of Advanced Energy, University of Tokyo, Kashiwa, Chiba 277-8561 (Japan); Herdrich, Georg [Institute of Space Systems (IRS), University of Stuttgart, 70569 Stuttgart, Baden-Wuerttemberg (Germany)

    2013-03-15

    Pulsed plasma thrusters are electric space propulsion devices which create a highly transient plasma bulk in a short-time arc discharge that is expelled to create thrust. The transitional character and the dependency on the discharge properties are yet to be elucidated. In this study, optical emission spectroscopy and Mach-Zehnder interferometry are applied to investigate the plasma properties in variation of time, space, and discharge energy. Electron temperature, electron density, and Knudsen numbers are derived for the plasma bulk and discussed. Temperatures were found to be in the order of 1.7 to 3.1 eV, whereas electron densities showed maximum values of more than 10{sup 17} cm{sup -3}. Both values showed strong dependency on the discharge voltage and were typically higher closer to the electrodes. Capacitance and time showed less influence. Knudsen numbers were derived to be in the order of 10{sup -3}-10{sup -2}, thus, indicating a continuum flow behavior in the main plasma bulk.

  10. ECR Plasma Sterilisation, Argon and Nitrogen Treated Plasma

    NASA Astrophysics Data System (ADS)

    Helhel, Selcuk; Oksuz, Lutfi; Cerezci, Osman; Rad, Abbas Y.

    2004-09-01

    ECR type plasma system was built to produce plasma in axial direction. Plasma was initiated in a specially designed Nickel - Chrome cylindrical vacuum tube which is being driven through dielectric window by 2.45GHz commercial magnetron source. Tube is also surrounded by a coil driving 150ADC to generate approximately 875Gauss magnetic field at the center. Langmuir probe and ICCD for optical spectrometry were used to characterize internal parameters like electron density, electron temperature and different characteristics of the plasma. Bacillus Subtilis var nigar, bacillus Stearothermophilus, bacillus pumilus E601, Escherichia coli and staphylococcus aureus type bacteria were selected as a reference. Each is resistant for different actions while the Bacilus cereus is the most resistant bacteria for microwave interaction. This study presents the effect of system on used bacteria. Those are gram positive and gram negative bacteria that refers to structure of cell wall. The sterilization efficacy of Argon type ECR plasma was found to be over 99, 5% in Staphylococcus aureus, Staphylococcus epidermidis, Bacillus subtilis (vegetative cell), Bacillus cereus (vegetative cell), Bacillus pumilus and Escherichia coli. System response type is less than 2 minutes.

  11. Wakes in Inertial Fusion Plasmas

    NASA Astrophysics Data System (ADS)

    Ellis, Ian Norman

    Plasma wave wakes, which are the collective oscillatory response near the plasma frequency to the propagation of particles or electromagnetic waves through a plasma, play a critical role in many plasma processes. New results from backwards stimulated Raman scattering (BSRS), in which wakes with phase velocities much less than the speed of light are induced by the beating of counter-propagating light waves, and from electron beam stopping, in which the wakes are produced by the motion of relativistically propagating electrons through the dense plasma, are discussed. Both processes play important roles in Inertial Confinement Fusion (ICF). In BSRS, laser light is scattered backwards out of the plasma, decreasing the energy available to compress the ICF capsule and affecting the symmetry of where the laser energy hits the hohlraum wall in indirect drive ICF. The plasma wave wake can also generate superthermal electrons that can preheat the core and/or the ablator. Electron beam stopping plays a critical role in the Fast Ignition (FI) ICF concept, in which a beam of relativistic electrons is used to heat the target core to ignition temperatures after the compression stage. The beam stopping power determines the effectiveness of the heating process. This dissertation covers new discoveries on the importance of plasma wave wakes in both BSRS and electron beam stopping. In the SRS studies, 1D particle-in-cell (PIC) simulations using OSIRIS are performed, which model a short-duration (˜500/?0 --1FWHM) counter-propagating scattered light seed pulse in the presence of a constant pump laser with an intensity far below the absolute instability threshold for plasma waves undergoing Landau damping. The seed undergoes linear convective Raman amplification and dominates over the amplification of fluctuations due to particle discreteness. The simulation results are in good agreement with results from a coupled-mode solver when special relativity and the effects of finite size PIC simulation particles are accounted for. Linear gain spectra including both effects are discussed. Extending the PIC simulations past when the seed exits the simulation domain reveals bursts of large-amplitude scattering in many cases, which do not occur in simulations without the seed pulse. These bursts can have amplitudes several times greater than the amplified seed pulse, and an examination of the orbits of particles trapped in the wake illustrates that the bursts are caused by a reduction of Landau damping due to particle trapping. This large-amplitude scattering is caused by the seed inducing a wake earlier in the simulation, thus modifying the distribution function. Performing simulations with longer duration seeds leads to parts of the seeds reaching amplitudes several times more than the steady-state linear theory results, similarly caused by a reduction of Landau damping. Simulations with continuous seeds demonstrate that the onset of inflation depends on the seed wavelength and incident intensity, and oscillations in the reflectivity are observed at a frequency equal to the difference between the seed frequency and the frequency at which the inflationary SRS grows. In the electron beam stopping studies, 3D PIC simulations are performed of relativistic electrons with a momentum of 10mec propagating in a cold FI core plasma. Some of the simulations use one simulation particle per real particle, and particle sizes much smaller than the interparitcle spacing. The wake made by a single electron is compared against that calculated using cold fluid theory assuming the phase velocity of the wake is near the speed of light. The results agree for the first wavelength of the wake. However, the shape of the wake changes for succeeding wavelengths and depends on the background plasma temperature, with the concavity pointing in the direction the electron is moving in cold plasmas and in the opposite direction as the plasma temperature increases. In the warm plasma the curvature is described by electrostatic Vlasov theory (for vparticle >> vth) and is due

  12. Basic concepts in plasma accelerators.

    PubMed

    Bingham, Robert

    2006-03-15

    In this article, we present the underlying physics and the present status of high gradient and high-energy plasma accelerators. With the development of compact short pulse high-brightness lasers and electron and positron beams, new areas of studies for laser/particle beam-matter interactions is opening up. A number of methods are being pursued vigorously to achieve ultra-high-acceleration gradients. These include the plasma beat wave accelerator (PBWA) mechanism which uses conventional long pulse ( approximately 100 ps) modest intensity lasers (I approximately 10(14)-10(16) W cm(-2)), the laser wakefield accelerator (LWFA) which uses the new breed of compact high-brightness lasers (<1 ps) and intensities >10(18) W cm(-2), self-modulated laser wakefield accelerator (SMLWFA) concept which combines elements of stimulated Raman forward scattering (SRFS) and electron acceleration by nonlinear plasma waves excited by relativistic electron and positron bunches the plasma wakefield accelerator. In the ultra-high intensity regime, laser/particle beam-plasma interactions are highly nonlinear and relativistic, leading to new phenomenon such as the plasma wakefield excitation for particle acceleration, relativistic self-focusing and guiding of laser beams, high-harmonic generation, acceleration of electrons, positrons, protons and photons. Fields greater than 1 GV cm(-1) have been generated with monoenergetic particle beams accelerated to about 100 MeV in millimetre distances recorded. Plasma wakefields driven by both electron and positron beams at the Stanford linear accelerator centre (SLAC) facility have accelerated the tail of the beams. PMID:16483948

  13. Autonomous Method and System for Minimizing the Magnitude of Plasma Discharge Current Oscillations in a Hall Effect Plasma Device

    NASA Technical Reports Server (NTRS)

    Hruby, Vladimir (Inventor); Demmons, Nathaniel (Inventor); Ehrbar, Eric (Inventor); Pote, Bruce (Inventor); Rosenblad, Nathan (Inventor)

    2014-01-01

    An autonomous method for minimizing the magnitude of plasma discharge current oscillations in a Hall effect plasma device includes iteratively measuring plasma discharge current oscillations of the plasma device and iteratively adjusting the magnet current delivered to the plasma device in response to measured plasma discharge current oscillations to reduce the magnitude of the plasma discharge current oscillations.

  14. Modeling of plasma and plasma-surface interactions for medical, environmental and nano applications

    NASA Astrophysics Data System (ADS)

    Bogaerts, A.; Aerts, R.; Snoeckx, R.; Somers, W.; Van Gaens, W.; Yusupov, M.; Neyts, E.

    2012-11-01

    In this paper, an overview is given of modeling investigations carried out in our research group for a better understanding of plasmas used for medical, environmental and nano applications. The focus is both on modeling the plasma chemistry and the plasma-surface interactions. The plasma chemistry provides the densities and fluxes of the important plasma species. This information can be used as input when modeling the plasma-surface interactions. The combination of plasma simulations and plasma - surface interaction simulations provides a more comprehensive understanding of the underlying processes for these applications.

  15. The Madison plasma dynamo experiment: A facility for studying laboratory plasma astrophysics

    E-print Network

    Cooper, C. M.

    The Madison plasma dynamo experiment (MPDX) is a novel, versatile, basic plasma research device designed to investigate flow driven magnetohydrodynamic instabilities and other high-? phenomena with astrophysically relevant ...

  16. Inductively coupled plasma heating in a weakly magnetized plasma

    NASA Astrophysics Data System (ADS)

    Kim, S. S.; Chang, C. S.; Yoon, N. S.; Whang, Ki-Woong

    1999-07-01

    A one-dimensional analysis of electron heating process in a weakly magnetized, inductively coupled plasma (MICP) is presented. It is found that the main difference in the heating process of a MICP from that of a usual unmagnetized ICP is in that circularly polarized wave modes can exist in the plasma. The right handed circularly polarized wave (R-wave) can propagate into the plasma and its amplitude can be enhanced by cavity resonance effect at an appropriate chamber length and external magnetic field strength. The enhanced R-wave amplitude can raise the heating efficiency significantly. It is also found that a bounce cyclotron-resonance effect can exist, which, however, is not as significant as the cavity resonance effect.

  17. Coherent control of plasma dynamics

    NASA Astrophysics Data System (ADS)

    He, Zhaohan

    2014-10-01

    The concept of coherent control - precise measurement or determination of a process through control of the phase of an applied oscillating field - has been applied to numerous systems with great success. Here, we demonstrate the use of coherent control on plasma dynamics in a laser wakefield electron acceleration experiment. A tightly focused femtosecond laser pulse (10 mJ, 35 fs) was used to generate electron beams by plasma wakefield acceleration in the density down ramp. The technique is based on optimization of the electron beam using a deformable mirror adaptive optical system with an iterative evolutionary genetic algorithm. The image of the electrons on a scintillator screen was processed and used in a fitness function as direct feedback for the optimization algorithm. This coherent manipulation of the laser wavefront leads to orders of magnitude improvement to the electron beam properties such as the peak charge and beam divergence. The laser beam optimized to generate the best electron beam was not the one with the ``best'' focal spot. When a particular wavefront of laser light interacts with plasma, it can affect the plasma wave structures and trapping conditions of the electrons in a complex way. For example, Raman forward scattering, envelope self-modulation, relativistic self-focusing, and relativistic self-phase modulation and many other nonlinear interactions modify both the pulse envelope and phase as the pulse propagates, in a way that cannot be easily predicted and that subsequently dictates the formation of plasma waves. The optimal wavefront could be successfully determined via the heuristic search under laser-plasma conditions that were not known a priori. Control and shaping of the electron energy distribution was found to be less effective, but was still possible. Particle-in-cell simulations were performed to show that the mode structure of the laser beam can affect the plasma wave structure and trapping conditions of electrons, which subsequently produces electron beams with a different divergence. The proof-of-principle demonstration of coherent control for plasmas opens new possibilities for future laser-based accelerators and their applications. This study should also enable a significantly improved understanding of the complex dynamics of laser plasma interactions. This work was supported by DARPA under Contract No. N66001-11-1-4208, the NSF under Contract No. 0935197 and MCubed at the University of Michigan.

  18. Plasma vitrification of asbestos fibers

    SciTech Connect

    Camacho, S.L. [Plasma Technology Corp., Raleigh, NC (United States)

    1995-12-31

    Asbestos is a mineral in the form of long, thread-like fibers. Asbestos fibers have been among the best insulators of pipes, boilers, ducts, tanks, etc., in buildings, ships, and industrial furnaces. Over 150,000 metric tons of asbestos were consumed in the United States in 1984. The Environmental Protection Agency has declared asbestos fibers a known human carcinogen. And today, asbestos insulators are being replaced by manmade non-hazardous fibers. Millions of tons of replaced asbestos fiber insulators are in storage, awaiting the demonstration of effective alternative disposal technologies. Plasma vitrification has been demonstrated during May, June and July 1995 as a viable, cost-effective, safe technology for asbestos fiber disposal. A low-mass plasma arc heater is submerged under the waste asbestos insulating materials, and the intense heat of the plasma flame heats and melts the fibers. The by-product is dark, non-hazardous glass pellets. The vitrification process renders the asbestos waste safe for use as road construction aggregates or other fill materials. This paper will describe the results of start-up of a 1 ton-per-hour Plasma Mobile Asbestos Vitrification (MAV) Plant at a DOD Site in Port Clinton, Ohio. The Plasma MAV Plant is being demonstrated for the on-site disposal of 1.5 million pounds of Amosite asbestos fibers.

  19. The plasma environment of Uranus

    NASA Technical Reports Server (NTRS)

    Belcher, J. W.; Mcnutt, R. L., Jr.; Richardson, J. D.; Selesnick, R. S.; Sittler, E. C., Jr.; Bagenal, F.

    1991-01-01

    An overview of the observational results on the plasma environment at Uranus is given, and the implications of these observations for magnetospheric physics at Uranus are discussed. During the Voyager 2 encounter with Uranus, an extended magnetosphere filled with a tenuous plasma was detected. This low-energy plasma was found to consist of protons and electrons, with no significant heavy ion contribution, and with a density in the regions sampled by the spacecraft of at most three electrons per cubic centimeter. The plasma electrons and ions exhibit both a thermal component (with temperatures of tens of eV) and a hot component (with temperatures of a few keV). The thermal ion component is observed both inside and outside an L-shell value near 5, whereas the hot ion and electron component is excluded from the region inside of that L-shell. The source of the thermal component of the plasma is either the planetary ionosphere or the neutral hydrogen corona surrounding Uranus, whereas the hot component is convected in from the magnetotail, with probably an ionospheric source.

  20. Theoretical investigations of plasma processes

    NASA Technical Reports Server (NTRS)

    Wilhelm, H. E.; Hong, S. H.

    1976-01-01

    System analyses are presented for electrically sustained, collision dominated plasma centrifuges, in which the plasma rotates under the influence of the Lorentz forces resulting from the interaction of the current density fields with an external magnetic field. It is shown that gas discharge centrifuges are technically feasible in which the plasma rotates at speeds up to 1 million cm/sec. The associated centrifugal forces produce a significant spatial isotope separation, which is somewhat perturbed in the viscous boundary layers at the centrifuge walls. The isotope separation effect is the more pronounced. The induced magnetic fields have negligible influence on the plasma rotation if the Hall coefficient is small. In the technical realization of collision dominated plasma centrifuges, a trade-off has to be made between power density and speeds of rotation. The diffusion of sputtered atoms to system surfaces of ion propulsion systems and the deposition of the atoms are treated theoretically by means of a simple model which permits an analytical solution. The problem leads to an inhomogeneous integral equation.

  1. Laboratory and Space Plasma Studies

    NASA Astrophysics Data System (ADS)

    Hyman, Ellis

    1996-08-01

    The work performed by Science Applications International Corporation (SAIC) on this contract, 'Laboratory and Space Plasma Studies,' Contract Number N00014-93-C-2178, SAIC Project Number 01-0157-03-6984, encompasses a wide range of topics in experimental, computational, and analytical laboratory and space plasma physics. The accomplishments described in this report have been in support of the programs of the Laser Plasma Branch (Code 6730) and other segments of the Plasma Physics Division at the Naval Research Laboratory (NRL) and cover the period 27 September 1993 to August 1, 1996. SAIC's efforts have been supported by subcontracts or consulting agreements with Pulse Sciences, Inc., Clark Richardson, and Biskup Consulting Engineers, Pharos Technical Enterprises, Plex Corporation, Cornell University, Stevens Institute of Technology, the University of Connecticut, Plasma Materials and Technologies, Inc., and GaSonics International, Inc. In the following discussions section we will describe each of the topics investigated and the results obtained. Much of the research work has resulted in journal publications and NRL Memorandum Reports in which the investigation is described in detail. These reports are included as Appendices to this Final Report.

  2. Relativistic Laser-Plasma Interactions

    SciTech Connect

    Skoric, Milos M. [National Institute for Fusion Science, Graduate University of Advanced Studies, Toki-shi (Japan)

    2009-11-10

    Ever since the much acclaimed paper of Akhiezer and Polovin plasma theorists have been attempting to comprehend complex dynamics related to the propagation of high and ultra-high intensity electromagnetic (EM) radiation through a plasma. This topic was successfully revisited a number of years later by Kaw and Dawson whose analysis threw more light on the propagation of coupled longitudinal-transverse waves of arbitrary intensity. The high phase velocity case was soon solved exactly by Max and Perkins, (early review). The problem of relativistic laser-plasma interactions is of particular interest concerning the fast ignition concept, relevant to contemporary laser inertial confinement fusion research. Moreover, the understanding of relativistic laser pulse evolution in a plasma is basic to many new applications, including optical-field-ionized x-ray lasers, plasma-based electron accelerator schemes, as well as, interpretation of some astrophysical phenomena, and references, therein). From a text given in two tutorial lectures, in a limited space, we mainly focus on an important paradigm of stimulated Raman scattering.

  3. Microwave diagnostics of atmospheric plasmas

    NASA Astrophysics Data System (ADS)

    Scott, David

    Plasma treatment of biological tissues has tremendous potential due to the wide range of applications. Most plasmas have gas temperatures which greatly exceed room temperature. These are often utilized in electro-surgery for cutting and coagulating tissue. Another type of plasma, referred to as cold atmospheric plasma, or CAP, is characterized by heavy particle temperatures which are at or near room temperature. Due to this lack of thermal effect, CAP may provide less invasive medical procedures. Additionally, CAP have been demonstrated to be effective at targeting cancer cells while minimizing damage to the surrounding tissue. A recently fabricated Microwave Electron Density Device (MEDD) utilizes microwave scattering on small atmospheric plasmas to determine the electron plasma density. The MEDD can be utilized on plasmas which range from a fraction of a millimeter to several centimeters at atmospheric pressure when traditional methods cannot be applied. Microwave interferometry fails due to the small size of the plasma relative to the microwave wavelength which leads to diffraction and negligible phase change; electrostatic probes introduce very strong perturbation and are associated with difficulties of application in strongly-collisional atmospheric conditions; and laser Thomson scattering is not sensitive enough to measure plasma densities less than 1012 cm-3. The first part of this dissertation provides an overview of two types of small atmospheric plasma objects namely CAPs and plasmas utilized in the electro-surgery. It then goes on to describe the fabrication, testing and calibration of the MEDD facility. The second part of this dissertation is focused on the application of the MEDD and other diagnostic techniques to both plasma objects. A series of plasma images that illustrate the temporal evolution of a discharge created by an argon electrosurgical device operating in the coagulation mode and its behavior was analyzed. The discharge of the argon electrosurgical system was studied using an Intensified Charge-Coupled Device (ICCD) and the MEDD. The plasma density was measured and found to be in the range of (7.5-9.5) x 1015 cm-3 for applied powers of 15-60 Watts. The discharge can be classified as a glow discharge of alternating current with a contracted positive column. The discharge ignites every half-wave of the driving voltage when voltage increases above the breakdown threshold of about 300 Volts and is interrupted at the end of each half-wave when the voltage approaches zero. Additionally, it was shown that the plasma discharges on the target object during the positive half-wave of the voltage. The power distribution was also analyzed. It was found that 60-70% of the input power is delivered into the tissue and the remaining 30-40% is consumed by the plasma column between the electrosurgical probe and tissue. The application of the MEDD to a helium CAP revealed the temporal dynamics of the discharge. It was observed that streamer development associated with the measured plasma density peak is developing on the decaying part of the main inter-electrode discharge. The third part of the dissertation focuses on the simulation of a helium CAP. A one-dimensional model of a helium CAP was used to simulate twenty-one oxygen, helium, and nitrogen species. One hundred and forty reactions were successfully used. The predicted maximum and average densities of the species were tabulated. Graphs of the species densities were presented showing the change in densities with respect to the radius of the CAP. The plasma bullets can be seen via these graphs, with most species displaying maximum densities at a radius which is not the center of the CAP. This shows that the plasma bullets are a disk-like structure at the moment of time presented. Values of E/p were varied from 20 -- 30 volts/cm Torr. Based on experimental results of moments in time with which the maximum plasma density occurs, this data can be used to predict the actual E/p values for future experiments.

  4. The High Fidelity Plasma Speaker

    NASA Astrophysics Data System (ADS)

    McGall, James

    2014-10-01

    A plasma speaker is a device that uses ionized gas as the driving source of sound production, rather than the traditional magnetic coil and membrane setup found on a standard speaker. Similar to how lightning produces sound, or even a small static shock, a plasma speaker uses a modulating electric arc between two electrodes to produce sound. An electric circuit is built that allows the variance of the high voltage electric potential to be controlled by a 3.5 mm standard audio headphone jack, allowing sound energy to be transferred from the plasma to the air by means of pulse width modulation. For my summer project I have built two different models of plasma speakers and am working on a third. The speaker benefits from having a nearly massless driver, and I hypothesize that it should show a response rate faster than that of a traditional speaker and a decreased impulse response while having the drawbacks of inefficiency and a low maximum decibel output. The speakers are currently being optimized with magnetic stabilization of the plasma and will be tested soon for impulse response, frequency generation, efficiency, and audio coloration. Bridges for SUCCESS Grant at Salisbury University under Ph.D. Matthew Bailey.

  5. Plasma Formation Around Single Wires

    NASA Astrophysics Data System (ADS)

    Duselis, Peter U.; Kusse, Bruce R.

    2002-12-01

    At Cornell's Laboratory of Plasma Studies, single wires of various metals were exploded using a ˜250 ns pulser with a rise time of ˜20 A/ns. It was found that the wires first experience a resistive heating phase that lasts 50-80 ns before a rapid collapse of voltage. From that point on, the voltage across the wire was negligible while the current through the wire continued to increase. We attribute this voltage collapse to the formation of plasma about the wire. Further confirmation of this explanation will be presented along with new experimental data describing preliminary spectroscopy results, the expansion rate of the plasma, and current flow along the wire as a function of radius. The resistance of the wire-electrode connection will be shown to significantly affect the energy deposition. Various diagnostics were used to obtain these experiments. Ultraviolet sensitive vacuum photodiodes and a framing camera with an 8 ns shutter were used to detect and measure the width of the visible light emitted by the plasma. A special wire holder was constructed that allowed the transfer of current from the wire to the surrounding plasma to be observed.

  6. Stationary Plasma Thruster Plume Emissions

    NASA Technical Reports Server (NTRS)

    Manzella, David H.

    1994-01-01

    The emission spectrum from a xenon plasma produced by a Stationary Plasma Thruster provided by the Ballistic Missile Defense Organization (BMDO) was measured. Approximately 270 individual Xe I, Xe II, and XE III transitions were identified. A total of 250 mW of radiated optical emission was estimated from measurements taken at the thruster exit plane. There was no evidence of erosion products in the emission signature. Ingestion and ionization of background gas at elevated background pressure was detected. The distribution of excited states could be described by temperatures ranging from fractions of 1 eV to 4 eV with a high degree of uncertainty due to the nonequilibrium nature of this plasma. The plasma was over 95 percent ionized at the thruster exit plane. Between 10 and 20 percent of the ions were doubly charged. Two modes of operation were identified. The intensity of plasma emission increased by a factor of two during operation in an oscillatory mode. The transfer between the two modes of operation was likely related to unidentified phenomena occurring on a time scale of minutes.

  7. Electromagnetic plasma models for microwave plasma cavity reactors

    NASA Technical Reports Server (NTRS)

    Frasch, L.; Asmussen, J.

    1984-01-01

    A procedure used to design cavity applicators that efficiently produce cylindrical and disk microwave discharges is reviewed. In contrast to most microwave applicators these cavities utilize single mode excitation of the plasma. This method of excitation has the advantage of providing efficient coupling (zero reflected power) to the plasma over a wide range of discharge loading conditions while also allowing, if desired, electric feedback control of the heating process. The design procedure is generalized to any lossy dielectric. Experimental and theoretical research required to further understand microwave discharges is also discussed.

  8. Two stream instabilities in degenerate quantum plasmas

    E-print Network

    S. Son

    2013-10-18

    The quantum mechanical effect on the plasma two-stream instability is studied based on the dielectric function approach. The analysis suggests that the degenerate plasma relevant to the inertial confinement fusion behaves differently from classical plasmas when the electron drift velocity is comparable to the Fermi velocity. For high wave vector comparable to the Fermi wave vector, the degenerate quantum plasma has larger regime of the two-stream instabilities than the classical plasma. A regime, where the plasma waves with the frequency larger than 1.5 times of the Langmuir wave frequency become unstable to the two-stream instabilities, is identified.

  9. Ion composition measurement techniques for space plasmas

    NASA Technical Reports Server (NTRS)

    Gloeckler, George

    1990-01-01

    Plasmas found in space range from the solar wind with a typical temperature of 100,000-1,000,000 K, about 400 km/s bulk flow speed, and high ionization (charge states) of ions, to the hot, slowly moving plasmas in the outer magnetospheres of the giant planets, to the cold, corotating plasmas in inner magnetospheres. Space plasma instruments and techniques are reviewed, with an emphasis on hot plasma composition measurements. Starting with Faraday Cup detectors some 30 years ago, plasma instruments have evolved to the present time-of-flight systems with excellent mass resolution and three-dimensional viewing capabilities.

  10. Coupled microwave ECR and radio-frequency plasma source for plasma processing

    DOEpatents

    Tsai, Chin-Chi (Oak Ridge, TN); Haselton, Halsey H. (Knoxville, TN)

    1994-01-01

    In a dual plasma device, the first plasma is a microwave discharge having its own means of plasma initiation and control. The microwave discharge operates at electron cyclotron resonance (ECR), and generates a uniform plasma over a large area of about 1000 cm.sup.2 at low pressures below 0.1 mtorr. The ECR microwave plasma initiates the second plasma, a radio frequency (RF) plasma maintained between parallel plates. The ECR microwave plasma acts as a source of charged particles, supplying copious amounts of a desired charged excited species in uniform manner to the RF plasma. The parallel plate portion of the apparatus includes a magnetic filter with static magnetic field structure that aids the formation of ECR zones in the two plasma regions, and also assists in the RF plasma also operating at electron cyclotron resonance.

  11. Coupled microwave ECR and radio-frequency plasma source for plasma processing

    DOEpatents

    Tsai, C.C.; Haselton, H.H.

    1994-03-08

    In a dual plasma device, the first plasma is a microwave discharge having its own means of plasma initiation and control. The microwave discharge operates at electron cyclotron resonance (ECR), and generates a uniform plasma over a large area of about 1000 cm[sup 2] at low pressures below 0.1 mtorr. The ECR microwave plasma initiates the second plasma, a radio frequency (RF) plasma maintained between parallel plates. The ECR microwave plasma acts as a source of charged particles, supplying copious amounts of a desired charged excited species in uniform manner to the RF plasma. The parallel plate portion of the apparatus includes a magnetic filter with static magnetic field structure that aids the formation of ECR zones in the two plasma regions, and also assists in the RF plasma also operating at electron cyclotron resonance. 4 figures.

  12. Tapered plasma channels to phase-lock accelerating and focusing forces in laser-plasma accelerators

    SciTech Connect

    Rittershofer, W.; Schroeder, C.B.; Esarey, E.; Gruner, F.J.; Leemans, W.P.

    2010-05-17

    Tapered plasma channels are considered for controlling dephasing of a beam with respect to a plasma wave driven by a weakly-relativistic, short-pulse laser. Tapering allows for enhanced energy gain in a single laser plasma accelerator stage. Expressions are derived for the taper, or longitudinal plasma density variation, required to maintain a beam at a constant phase in the longitudinal and/or transverse fields of the plasma wave. In a plasma channel, the phase velocities of the longitudinal and transverse fields differ, and, hence, the required tapering differs. The length over which the tapered plasma density becomes singular is calculated. Linear plasma tapering as well as discontinuous plasma tapering, which moves beams to adjacent plasma wave buckets, are also considered. The energy gain of an accelerated electron in a tapered laser-plasma accelerator is calculated and the laser pulse length to optimize the energy gain is determined.

  13. Plasma Panel Based Radiation Detectors

    SciTech Connect

    Friedman, Dr. Peter S. [Integrated Sensors, LLC; Varner Jr, Robert L [ORNL; Ball, Robert [University of Michigan; Beene, James R [ORNL; Ben Moshe, M. [Tel Aviv University; Benhammou, Yan [Tel Aviv University; Chapman, J. Wehrley [University of Michigan; Etzion, E [Tel Aviv University; Ferretti, Claudio [University of Michigan; Bentefour, E [Ion Beam Applications; Levin, Daniel S. [University of Michigan; Moshe, M. [Tel Aviv University; Silver, Yiftah [Tel Aviv University; Weaverdyck, Curtis [University of Michigan; Zhou, Bing [University of Michigan

    2013-01-01

    The plasma panel sensor (PPS) is a gaseous micropattern radiation detector under current development. It has many operational and fabrication principles common to plasma display panels (PDPs). It comprises a dense matrix of small, gas plasma discharge cells within a hermetically sealed panel. As in PDPs, it uses non-reactive, intrinsically radiation-hard materials such as glass substrates, refractory metal electrodes, and mostly inert gas mixtures. We are developing these devices primarily as thin, low-mass detectors with gas gaps from a few hundred microns to a few millimeters. The PPS is a high gain, inherently digital device with the potential for fast response times, fine position resolution (< 50 m RMS) and low cost. In this paper we report here on prototype PPS experimental results in detecting betas, protons and cosmic muons, and we extrapolate on the PPS potential for applications including detection of alphas, heavy-ions at low to medium energy, thermal neutrons and X-rays.

  14. Plasma-catalyzed fuel reformer

    DOEpatents

    Hartvigsen, Joseph J.; Elangovan, S.; Czernichowski, Piotr; Hollist, Michele

    2013-06-11

    A reformer is disclosed that includes a plasma zone to receive a pre-heated mixture of reactants and ionize the reactants by applying an electrical potential thereto. A first thermally conductive surface surrounds the plasma zone and is configured to transfer heat from an external heat source into the plasma zone. The reformer further includes a reaction zone to chemically transform the ionized reactants into synthesis gas comprising hydrogen and carbon monoxide. A second thermally conductive surface surrounds the reaction zone and is configured to transfer heat from the external heat source into the reaction zone. The first thermally conductive surface and second thermally conductive surface are both directly exposed to the external heat source. A corresponding method and system are also disclosed and claimed herein.

  15. Lagrangian description of warm plasmas

    NASA Technical Reports Server (NTRS)

    Kim, H.

    1970-01-01

    Efforts are described to extend the averaged Lagrangian method of describing small signal wave propagation and nonlinear wave interaction, developed by earlier workers for cold plasmas, to the more general conditions of warm collisionless plasmas, and to demonstrate particularly the effectiveness of the method in analyzing wave-wave interactions. The theory is developed for both the microscopic description and the hydrodynamic approximation to plasma behavior. First, a microscopic Lagrangian is formulated rigorously, and expanded in terms of perturbations about equilibrium. Two methods are then described for deriving a hydrodynamic Lagrangian. In the first of these, the Lagrangian is obtained by velocity integration of the exact microscopic Lagrangian. In the second, the expanded hydrodynamic Lagrangian is obtained directly from the expanded microscopic Lagrangian. As applications of the microscopic Lagrangian, the small-signal dispersion relations and the coupled mode equations are derived for all possible waves in a warm infinite, weakly inhomogeneous magnetoplasma, and their interactions are examined.

  16. Wave particle interactions in plasmas

    NASA Astrophysics Data System (ADS)

    Koch, R.

    2006-12-01

    An overview of the interactions between waves and particles in plasmas is given. Interest is focused on cases where special particle populations, like energetic particle tails, interact with waves. The two basic, but inter-related, mechanisms through which waves and particles can exchange energy, resonance and stochastization are briefly illustrated. The basic non-collisional interaction mechanisms and their description through quasilinear theory are reviewed. The present state of modelling and comparison with experiments in fusion plasmas is addressed. With respect to astrophysical plasmas, three topics are examined: (i) the generation of cosmic rays, (ii) the heating and fast particle generation in the solar corona and (iii) the whistler wave generation in the magnetosphere.

  17. Plasma Injection Experiment at MCX

    NASA Astrophysics Data System (ADS)

    Uzun-Kaymak, Ilker; Messer, S.

    2008-11-01

    MCX uses an axial magnetic field and a radial voltage to drive supersonic azimuthal flows. It has been observed that the high flow velocity and large radial velocity shear suppresses the higher order interchange modes. However, the MCX discharges are currently limited by the charge and current available from the capacitor bank supplying the radial voltage. The High Density Plasma Injection Experiment combines the MCX experiment with a modified coaxial plasma gun to drive rotation in the target vessel. A 32-injector prototype coaxial gun has been designed, constructed and installed at MCX midplane, top tangential port, as alternate means of momentum input. Unlike traditional coaxial plasma jets, the transport of the jet has been optimized via a combination of electrode shaping and tailored armature at HyperV Technologies Corp. in order to prevent the blow-by instability. Data will be presented for a wide range of MCX parameters and the prospects for future injection experiments will be evaluated.

  18. Charged Dust Structures in Plasmas

    NASA Astrophysics Data System (ADS)

    Cramer, N. F.; Vladimirov, S. V.

    Recent advances in the study of collective effects and particle motions in plasma-dust crystals, ordered structures that form in the cathode sheath region of low temperature gaseous discharges, are presented. Plasma collective processes influence the arrangements and vibrations of dust particles in these Coulomb-lattice structures. One important effect is the wake potential formation due to ion flow, leading to the vertical alignment of dust grains in experiments. The oscillations of dust particles in the lattices are strongly affected by collective processes in the ambient plasma, in particular by the wake. Modes associated with vertical vibrations of dust grains are identified, and their dispersion characteristics are discussed. The modes can provide a useful tool for diagnostics in the sheath region of the discharge.

  19. Nonlinear dynamics and plasma transport

    SciTech Connect

    Antonsen, T.M. Jr.; Drake, J.F.; Finn, J.M.; Guzdar, P.N.; Hassam, A.B.; Sageev, R.Z.

    1993-01-01

    This progress report details work done on a program in nonlinear dynamical aspects of plasma turbulence and transport funded by DOE since 1989. This program has been in cooperation with laboratories in theUSSR [now Russia and the Confederation of Independent States (CIS)]. The purpose of this program has been: To promote the utilization of recent pathbreaking developments in nonlinear science in plasma turbulence and transport. To promote cooperative scientific investigations between the US and CIS in the related areas of nonlinear science and plasma turbulence and transport. In the work reported in our progress report, we have studied simple models which are motivated by observation on actual fusion devices. The models focus on the important physical processes without incorporating the complexity of the geometry of real devices. This allows for a deeper analysis and understanding of the system both analytically and numerically.

  20. Attosecond emission from chromium plasma.

    PubMed

    Elouga Bom, L B; Haessler, S; Gobert, O; Perdrix, M; Lepetit, F; Hergott, J-F; Carré, B; Ozaki, T; Salières, P

    2011-02-14

    We present the first measurement of the attosecond emission generated from underdense plasma produced on a solid target. We generate high-order harmonics of a femtosecond Ti:sapphire laser focused in a weakly ionized underdense chromium plasma. Using the "Reconstruction of Attosecond Beating by Interference of Two-photon Transitions" (RABITT) technique, we show that the 11th to the 19th harmonic orders form in the time domain an attosecond pulse train with each pulse having 300 as duration, which is only 1.05 times the theoretical Fourier transform limit. Measurements reveal a very low positive group delay dispersion of 4200 as2. Beside its fundamental interest, high-order harmonic generation in plasma plumes could thus provide an intense source of attosecond pulses for applications. PMID:21369193

  1. Nonlinear dynamics experiments in plasmas

    E-print Network

    Nurujjaman, Md

    2009-01-01

    The study of nonlinear dynamics or chaos theory has emerged in the last three decades or so as an important interdisciplinary area of research encompassing a wide range of fields like: fluids, plasmas, biomedical sciences, finance, turbulence, astronomy, material sciences, etc. In plasma chaos was first experimentally observed by Boswell. Different other nonlinear dynamics related phenomena like, the intermittency route to a chaos, Homoclinic chaos, Period adding route to chaos and period subtracting, mode locking, period pulling, etc., had been observed by several researchers. In this thesis, we have presented (a) anode glow related observation of chaos to order transition and homoclinic bifurcation; (b) coherence resonance and stochastic resonance; and self organized criticality behavior in glow discharge plasma.

  2. Collective excitations of supersymmetric plasma

    NASA Astrophysics Data System (ADS)

    Czajka, Alina; Mrówczy?ski, Stanis?aw

    2011-02-01

    Collective excitations of N=1 supersymmetric electromagnetic plasma are studied. Since the Keldysh-Schwinger approach is used, not only equilibrium but also nonequilibrium plasma, which is assumed to be ultrarelativistic, is under consideration. The dispersion equations of photon, photino, electron, and selectron modes are written down and the self-energies, which enter the equations, are computed in the hard loop approximation. The self-energies are discussed in the context of effective action which is also given. The photon modes and electron ones appear to be the same as in the usual ultrarelativistic plasma of electrons, positrons, and photons. The photino modes coincide with the electron ones and the selectron modes are as of a free relativistic massive particle.

  3. Alternative approaches to plasma confinement

    NASA Technical Reports Server (NTRS)

    Roth, J. R.

    1978-01-01

    The paper discusses 20 plasma confinement schemes each representing an alternative to the tokamak fusion reactor. Attention is given to: (1) tokamak-like devices (TORMAC, Topolotron, and the Extrap concept), (2) stellarator-like devices (Torsatron and twisted-coil stellarators), (3) mirror machines (Astron and reversed-field devices, the 2XII B experiment, laser-heated solenoids, the LITE experiment, the Kaktus-Surmac concept), (4) bumpy tori (hot electron bumpy torus, toroidal minimum-B configurations), (5) electrostatically assisted confinement (electrostatically stuffed cusps and mirrors, electrostatically assisted toroidal confinement), (6) the Migma concept, and (7) wall-confined plasmas. The plasma parameters of the devices are presented and the advantages and disadvantages of each are listed.

  4. Theory of beam plasma discharge

    NASA Technical Reports Server (NTRS)

    Papadopoulos, K.

    1982-01-01

    The general theory of beam plasma discharge (BPD) is discussed in relation to space and laboratory beam injection situations. An important concept introduced is that even when beam plasma instabilities are excited, there are two regime of BPD with radically different observational properties. They are described here as BPD with either classical or anomalous energy depositions. For high pressures or low altitudes, the classical is expected to dominate. For high altitudes and laboratory experiments, where the axial system size is less than lambda sub en, no BPD will be triggered unless the unstable waves are near the ambient plasma frequency and their amplitudes at saturation are large enough to create suprathermal tails by collapsing.

  5. Plasma Wakefield Experiments at FACET

    SciTech Connect

    Hogan, M.J.; England, R.J.; Frederico, J.; Hast, C.; Li, S.Z.; Litos, M.; Walz, D.; /SLAC; An, W.; Clayton, C.E.; Joshi, C.; Lu, W.; Marsh, K.A.; Mori, W.; Tochitsky, S.; /UCLA; Muggli, P.; Pinkerton, S.; Shi, Y.; /Southern California U.

    2011-08-19

    FACET, the Facility for Advanced Accelerator and Experimental Tests, is a new facility being constructed in sector 20 of the SLAC linac primarily to study beam driven plasma wakefield acceleration beginning in summer 2011. The nominal FACET parameters are 23GeV, 3nC electron bunches compressed to {approx}20{micro}m long and focused to {approx}10{micro}m wide. The intense fields of the FACET bunches will be used to field ionize neutral lithium or cesium vapor produced in a heat pipe oven. Previous experiments at the SLAC FFTB facility demonstrated 50GeV/m gradients in an 85cm field ionized lithium plasma where the interaction distance was limited by head erosion. Simulations indicate the lower ionization potential of cesium will decrease the rate of head erosion and increase single stage performance. The initial experimental program will compare the performance of lithium and cesium plasma sources with single and double bunches. Later experiments will investigate improved performance with a pre-ionized cesium plasma. The status of the experiments and expected performance are reviewed. The FACET Facility is being constructed in sector 20 of the SLAC linac primarily to study beam driven plasma wakefield acceleration. The facility will begin commissioning in summer 2011 and conduct an experimental program over the coming five years to study electron and positron beam driven plasma acceleration with strong wake loading in the non-linear regime. The FACET experiments aim to demonstrate high-gradient acceleration of electron and positron beams with high efficiency and negligible emittance growth.

  6. Analysis of the plasma sweeper

    SciTech Connect

    Glanz, J.; Motley, R.W.

    1982-09-01

    The coupling of lower hybrid waves to a plasma can be modified by placing potentials on electrodes near the mouth of a phased array. Positive potentials on the electrodes create an electric field that sweeps the plasma away at a velocity c anti E x anti B/B/sup 2/. In this paper we derive the electric field created by the applied potential from the nondivergent character of the current flow and the ion momentum equation, in which ion-neutral charge-exchange collisions are retained, and we compare the predictions with experimental data.

  7. Dust Growth in Astrophysical Plasmas

    NASA Astrophysics Data System (ADS)

    Bingham, R.; Tsytovich, V. N.

    2002-12-01

    Dust formation in space is important in diverse environments such as dust molecular clouds, proto-planetary nebulae, stellar outbursts, and supernova explosions. The formation of dust proceeds the formation of stellar objects and planets. In all these environments the dust particles interact with both neutral and plasma particles as well as with (ultraviolet) radiation and cosmic rays. The conventional view of grain growth is one based on accretion by the Van der Waals and chemical forces [Watson and Salpeter [14] considered in detail both theoretically and numerically (Kempf at all [6],Meaking [7]( and confirmed recently by micro-gravity experiments Blum et all [2]). The usual point of view is that the dust grow is occurring in dust molecular clouds at very low temperatures ~ (10 - 30)° K and is a slow process - dust grows to a size of about 0.1 ?m in 106 - 109 years. This contradicts recent observations of dust growing in winds of C-stars in about 10 years and behind the supernova SN1987A shock in about 500 days. Also recent observation of star formation at the edge of irradiated dust clouds suggests that new plasma mechanism operates in star formation. Dusty plasma mechanisms of agglomeration are analyzed as an explanation of the new astrophysical observation. New micro-gravity experiments are proposed for observing the plasma mechanisms of dust agglomeration at gas pressures substantially higher than used in ([2]. Calculations for the growth rates of dust agglomeration due to plasma mechanisms are presented. It is shown that at large neutral gas densities the dust plasma attraction provides an explanation of dust grow in about 10 days observed in H-star winds. Ionization by cosmic rays and by radioactive dust can provide the dust attraction necessary for forming dust clumping observed in molecular clouds and the fractal plasma clumping can enhance the time to reach the gravitational contraction phase operating at the final stage of star formation. A new gravitation-like dust clumping instability should operate in the dust molecular clouds at the time scale of md/nnTna4nd (standard notations used) and for molecular cloud conditions nd ~ 10-3 cm-3, nn ~ 103 cm-3, Tn ~ 10 K, a ~ 3 ?m the dust agglomeration time is 3 orders of magnitude smaller than the gravitation instability time. The characteristic lengths is of the order ~ (1011 - 1012) cm which is 3 orders of magnitude less than the Jeans length. This new plasma mechanism can be important in star and planetesimal formation.

  8. Ballistic piston fissioning plasma experiment.

    NASA Technical Reports Server (NTRS)

    Miller, B. E.; Schneider, R. T.; Thom, K.; Lalos, G. T.

    1971-01-01

    The production of fissioning uranium plasma samples such that the fission fragment stopping distance is less than the dimensions of the plasma is approached by using a ballistic piston device for the compression of uranium hexafluoride. The experimental apparatus is described. At room temperature the gun can be loaded up to 100 torr UF6 partial pressure, but at compression a thousand fold increase of pressure can be obtained at a particle density on the order of 10 to the 19th power per cu cm. Limited spectral studies of UF6 were performed while obtaining the pressure-volume data. The results obtained and their implications are discussed.

  9. Magnetoplasmons in Rotating Dusty Plasmas

    NASA Astrophysics Data System (ADS)

    Hartmann, Peter; Donkó, Zoltán; Ott, Torben; Kählert, Hanno; Bonitz, Michael

    2013-10-01

    A rotating dusty plasma apparatus was constructed to provide the possibility of experimental emulation of extremely high magnetic fields by means of the Coriolis force, observable in a corotating measurement frame. We present collective excitation spectra for different rotation rates with a magnetic induction equivalent of up to 3200 T. We identify the onset of magnetoplasmon-equivalent mode dispersion in the rotating macroscopic two-dimensional single-layer dusty plasma. The experimental results are supported by molecular dynamics simulations of 2D magnetized Yukawa systems.

  10. Adiabatic evolution of plasma equilibrium

    PubMed Central

    Grad, H.; Hu, P. N.; Stevens, D. C.

    1975-01-01

    A new theory of plasma equilibrium is introduced in which adiabatic constraints are specified. This leads to a mathematically nonstandard structure, as compared to the usual equilibrium theory, in which prescription of pressure and current profiles leads to an elliptic partial differential equation. Topologically complex configurations require further generalization of the concept of adiabaticity to allow irreversible mixing of plasma and magnetic flux among islands. Matching conditions across a boundary layer at the separatrix are obtained from appropriate conservation laws. Applications are made to configurations with planned islands (as in Doublet) and accidental islands (as in Tokamaks). Two-dimensional, axially symmetric, helically symmetric, and closed line equilibria are included. PMID:16578729

  11. Evaporative cooling of flare plasma

    NASA Technical Reports Server (NTRS)

    Antiochos, S. K.; Sturrock, P. A.

    1976-01-01

    A one-dimensional loop model for the evaporative cooling of the coronal flare plasma was investigated. Conductive losses dominated radiative cooling, and the evaporative velocities were small compared to the sound speed. The profile and evolution of the temperature were calculated. The model was in agreement with soft X-ray observations on the evolution of flare temperatures and emission measures. The effect of evaporation was to greatly reduce the conductive heat flux into the chromosphere and to enhance the EUV emission from the coronal flare plasma.

  12. Hopf bifurcation and plasma instabilities

    SciTech Connect

    Crawford, J.D.

    1983-11-01

    Center manifold theory and the theory of normal forms are applied to examples of Hopf bifurcation in two models of plasma dynamics. A finite dimensional model of a 3-wave system with quadratic nonlinearities provides a simple example of both supercritical and subcritical Hopf bifurcation. In the second model, the electrostatic instabilities of a collisional plasma correspond to Hopf bifurcations. In this problem, the Vlasov-Poisson equations with a Krook collision term describe the electron dynamics in a weakly ionized gas. The one mode in instability is analyzed in detail; near criticality it always saturates in a small amplitude nonlinear oscillation.

  13. Relativistic effects on plasma expansion

    SciTech Connect

    Benkhelifa, El-Amine; Djebli, Mourad, E-mail: mdjebli@usthb.dz [USTHB, Faculty of Physics, Theoretical Physics Laboratory, B.P. 32 Bab-Ezzouar, 16079 Algiers (Algeria)

    2014-07-15

    The expansion of electron-ion plasma is studied through a fully relativistic multi-fluids plasma model which includes thermal pressure, ambipolar electrostatic potential, and internal energy conversion. Numerical investigation, based on quasi-neutral assumption, is performed for three different regimes: nonrelativistic, weakly relativistic, and relativistic. Ions' front in weakly relativistic regime exhibits spiky structure associated with a break-down of quasi-neutrality at the expanding front. In the relativistic regime, ion velocity is found to reach a saturation limit which occurs at earlier stages of the expansion. This limit is enhanced by higher electron velocity.

  14. Laser plasma coupling with moderate Z, long scalelength underdense plasma

    NASA Astrophysics Data System (ADS)

    Kruer, William; Berger, Richard; Meezan, Nathaniel; Suter, Larry; Moody, John; Glenzer, Siegfried; Stevenson, R. M.; Oades, K.

    2004-11-01

    Recent experiments1,2 have focussed new attention on the coupling of laser light with moderate Z, long scalelength underdense plasmas. We discuss some intriguing features of these experiments, including a significant reduction of stimulated Raman and Brillouin scattering in higher Z plasmas, such as Krypton and Xenon. Threshold conditions for various instabilities are discussed, and potential consequences of thermal filamentation and self-focussing are explored. The presence of significant temperature modulations in the plasma can lead to a number of interesting effects not usually taken into account, such as ion wave refraction out of hot spots and instability reduction by the long wavelength modulations. We also consider the extrapolation of these results to the higher temperature regimes more relevant to ignition-scale hohlraums. 1. R. M. Stevenson, et. al, Phys. Plasmas 11, 2709 (2004) 2. J. Moody (to be published) Work performed under the auspices of the U.S. DOE by the Lawrence Livermore National Laboratory under Contract W-7405-ENG-48.

  15. Effects of Plasma Instabilities on Tungsten Divertor Plate

    E-print Network

    (HEIGHTS Package) · Plasma-Target Interaction · Plasma particles energy deposition (ions + electrons · Plasma energy deposition in debris · Debris hydrodynamic evolution · Debris/vapor magneto radiation · Plasma-Melt Layer Interaction · Splashing due to bubble formation and evaporation · Splashing

  16. Non-thermal plasmas in flames and other inhomogeneous environments

    E-print Network

    Guerra García, Carmen

    2015-01-01

    Non-thermal plasmas in non-uniform gases appear in several technological applications (plasma assisted combustion and aerodynamics, and plasma jets), as well as in natural phenomena (sprites). Whereas in the case of plasma ...

  17. Biomedical Applica ons of Low Temperature Plasmas

    E-print Network

    discussion of the interac on of low tempera ture plasma with biological cells, both prokaryotes on of surfaces Plasmacell interac on: prokaryotes Plasmacell interac on: eukaryotes Plasma Based biomedical

  18. The plasma focus as a thruster 

    E-print Network

    Hardy, Richard Lee

    2005-02-17

    The need for low propellant weight, high efficiency propulsion systems is a glaring need for various space missions. This thesis presents the thrust modeling of the Dense Plasma Focus plasma motion phases. It also contrasts some of the engineering...

  19. Laser frequency modulation with electron plasma

    NASA Technical Reports Server (NTRS)

    Burgess, T. J.; Latorre, V. R.

    1972-01-01

    When laser beam passes through electron plasma its frequency shifts by amount proportional to plasma density. This density varies with modulating signal resulting in corresponding modulation of laser beam frequency. Necessary apparatus is relatively inexpensive since crystals are not required.

  20. Theory of edge plasma in a spheromak

    SciTech Connect

    Hooper, E.B., LLNL

    1998-05-01

    Properties of the edge plasma in the SSPX spheromak during the plasma formation and sustainment phases are discussed. For the breakdown and formation phase, the main emphasis is on the analysis of possible plasma contamination by impurities from the electrodes of the plasma gun (helicity injector). The issue of an azimuthally uniform breakdown initiation is also discussed. After the plasma settles down in the main vacuum chamber, one has to sustain the current between the electrodes, in order to continuously inject helicity. We discuss properties of the plasma on the field lines intersecting the electrodes. We conclude that the thermal balance of this plasma is maintained by Joule heating competing with parallel heat losses to the electrodes. The resulting plasma temperature is in the range of 15 - 30 eV. Under the expected operational conditions, the ``current`` velocity of the electrons is only slightly below their thermal velocity. Implications of this observation are briefly discussed.