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1

Plasma heating from alpha particle micro-instabilities  

SciTech Connect

Potential use of thermonuclear (i.e., fusion product) driven kinetic instabilities to heat the background plasma has long been recognized. Considerable research on velocity space micro-instabilities exists. Most work to date has focused upon the basic physics criteria for and characteristics of particular micro-instabilities. Kinetic instabilities resulting in spatial transport of fusion products have also received some attention, but the effects on reactor concepts and performance remain uncertain. We have developed an engineering model which scopes the effect of a velocity space relaxation of fast alphas on a quasi-linear time scale. This model includes the additional heating to background plasma ions under the assumptions of: ion damping of the plasma wave; heating to background plasma results predominantly from fusion products; and periodic hiccups of the instability.

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

1981-01-01

2

Kinetic studies of microinstabilities in toroidal plasmas: Simulation and theory  

SciTech Connect

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.

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

3

Kinetic studies of microinstabilities in toroidal plasmas: Simulation and theory  

SciTech Connect

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.

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

4

Structure of micro-instabilities in tokamak plasmas: Stiff transport or plasma eruptions?  

SciTech Connect

Solutions to a model 2D eigenmode equation describing micro-instabilities in tokamak plasmas are presented that demonstrate a sensitivity of the mode structure and stability to plasma profiles. In narrow regions of parameter space, with special plasma profiles, a maximally unstable mode is found that balloons on the outboard side of the tokamak. This corresponds to the conventional picture of a ballooning mode. However, for most profiles, this mode cannot exist, and instead, a more stable mode is found that balloons closer to the top or bottom of the plasma. Good quantitative agreement with a 1D ballooning analysis is found, provided the constraints associated with higher order profile effects, often neglected, are taken into account. A sudden transition from this general mode to the more unstable ballooning mode can occur for a critical flow shear, providing a candidate model for why some experiments observe small plasma eruptions (Edge Localised Modes, or ELMs) in place of large Type I ELMs.

Dickinson, D., E-mail: dd502@york.ac.uk [York Plasma Institute, Department of Physics, University of York, Heslington, York YO10 5DD (United Kingdom); EURATOM/CCFE Fusion Association, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Roach, C. M. [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); Skipp, J. M.; Wilson, H. R. [York Plasma Institute, Department of Physics, University of York, Heslington, York YO10 5DD (United Kingdom)] [York Plasma Institute, Department of Physics, University of York, Heslington, York YO10 5DD (United Kingdom)

2014-01-15

5

High-frequency microinstabilities in hot-electron plasmas  

SciTech Connect

Instabilities with frequencies in the neighborhood of the electron cyclotron frequency are of interest in determining stable operating regimes of hot-electron plasmas in EBT devices and in tandem mirrors. Previous work used model distributions significantly different than those suggested by recent Fokker-Planck studies. We use much more realistic model distributions in a computer code that solves the full electromagnetic dispersion relation governing longitudinal and transverse waves in a uniform plasma. We allow for an arbitrary direction of wave propagation. Results for the whistler and upper-hybrid loss-cone instabilities are presented.

Chen, Y.J.; Nevins, W.M.; Smith, G.R.

1981-11-24

6

Kinetic Self-Organization of Microinstabilities in Astrophysical and in Laboratory Plasmas  

NASA Astrophysics Data System (ADS)

Microinstabilities can be considered as effective collisions. The small scale electromagnetic fluctuations due to microinstabilties can be considered as collisions on the particles, leading to a similar point-like and instantaneous-like change in the particle momentum. This paradigm, the anomalous transport paradigm, requires us to derive theories that can predict the correct transport parameters (particularly the anomalous viscosity and anomalous resistivity) from the properties of the microinstabilties. Our recent work [1-3] has shown that another possible effect of microinstabilties is to lead to a direct macroscopic change in the equilibrium by affecting the plasma flow, temperature anisotropy and current profile on a macroscopic level. Our previous work has focused on space and astrophysical systems. But similar effects can be considered for experimental plasmas. A particularly intriguing possible analogy is with zonal flows and ``angular momentum generation'' believed to be happening in accretion disks in astrophysical systems [4] and with the ``spontaneous toroidal rotation'' of axisymmetric plasmas in fusion devices such as Jet and Alcator C-Mod [5]. [1] G. Lapenta, J.U. Brackbill, W.S. Daughton, Phys. Plasmas, 10, 1577 (2003). [2] W. Daughton, G. Lapenta, P. Ricci, Phys. Rev. Lett., 93, 105004, 2004 [3] P. Ricci, J.U. Brackbill, W.S. Daughton, G. Lapenta, Phys. Plasmas, 11, 4102, 2004. [4] B. Coppi 2002 Nucl. Fusion 42 1-4 [5] E. S. Marmar, et al., Fusion Energy 2002 (IAEA, Vienna) Paper OV/4-1

Lapenta, Giovanni

2006-04-01

7

PUBLISHED VERSION Structure of micro-instabilities in tokamak plasmas: Stiff transport or plasma eruptions?  

E-print Network

eruptions? D. Dickinson, C. M. Roach, J. M. Skipp, and H. R. Wilson © 2013 UNITED KINGDOM ATOMIC ENERGY plasmas: Stiff transport or plasma eruptions? D. Dickinson, C. M. Roach, J. M. Skipp, and H. R. Wilson transport or plasma eruptions? D. Dickinson,1,2,a) C. M. Roach,2 J. M. Skipp,1 and H. R. Wilson1 1 York

8

Macroscopic description for a quantum plasma micro-instability: the quantum Weibel solution  

E-print Network

The Weibel instability in the quantum plasma case is treated by means of a fluid-like (moments) approach. Quantum modifications to the macroscopic equations are then identified as effects of first or second kind. Quantum effects of the first kind correspond to a dispersive term, similar to the Bohm potential in the quantum hydrodynamic equations for plasmas. Effects of the second kind are due to the Fermi statistics of the charge carriers and can become the dominant influence for strong degeneracy. The macroscopic dispersion relations are of higher order than those for the classical Weibel instability. This corresponds to the presence of a cutoff wave-number even for the strong temperature anisotropy case.

Fernando Haas; Marian Lazar

2008-01-25

9

Microinstabilities in weak density gradient tokamak systems  

SciTech Connect

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.

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

1986-04-01

10

Microinstabilities in the Gasdynamic Mirror Propulsion System  

NASA Technical Reports Server (NTRS)

The gasdynamic mirror has been proposed as a concept which could form the basis of a highly efficient fusion rocket engine. Gasdynamic mirrors differ from most other mirror type plasma confinement schemes in that they have much larger aspect ratios and operate at somewhat higher plasma densities. There are several types of instabilities which are known to plague mirror type confinement schemes. These instabilities fall into two general classes. One class of instability is the Magnetohdrodynamic or MHD instability which induces gross distortions in the plasma geometry. The other class of instability is the "loss cone" microinstability which leads to general plasma turbulence. The "loss cone" microinstability is caused by velocity space asymmetries resulting from the loss of plasma having constituent particle velocities within the angle of the magnetic mirror "loss cone." These instabilities generally manifest themselves in high temperature, moderately dense plasmas. The present study indicates that a GDM configured as a rocket engine might operate in a plasma regine where microinstabilities could potentially be significant.

Emrich, William

2005-01-01

11

Microinstabilities in the Gasdynamic Mirror Propulsion System  

NASA Technical Reports Server (NTRS)

The gasdynamic mirror has been proposed as a concept which could form the basis of a highly efficient fusion rocket engine. Gasdynamic mirrors differ from most other mirror type plasma confinement schemes in that they have much larger aspect ratios and operate at somewhat higher plasma densities. There are several types of instabilities which are known to plague mirror type confinement schemes. These instabilities fall into two general classes. One class of instability is the Magnetohydrodynamic or MHD instability which induces gross distortions in the plasma geometry. The other class of instability is the "loss cone" microinstability which leads to general plasma turbulence. The "loss cone" microinstability is caused by velocity space asymmetries resulting from the loss of plasma having constituent particle velocities within the angle of the magnetic mirror "loss cone." These instabilities generally manifest themselves in high temperature, moderately dense plasmas. The present study indicates that a GDM configured as a rocket engine might operate in a plasma regime where microinstabilities could potentially be significant.

Emrich, William

2005-01-01

12

Finite-? simulation of microinstabilities  

SciTech Connect

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.

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

13

Microinstability-based model for anomalous thermal confinement in tokamaks  

SciTech Connect

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.

Tang, W.M.

1986-03-01

14

Microinstability and internal impingement in overhead athletes.  

PubMed

A complex interplay exists between the static and dynamic stabilizers in the glenohumeral joint, especially in overheard athletes who need a shoulder hypermobile enough to perform overhead activity yet stable enough to prevent joint subluxation. Concomitant shoulder pathologies commonly occur in the setting of microinstability and internal impingement. Before any surgical intervention, a 3- to 6-month course of conservative measures should first be attempted, with exercises focused on rotator cuff and scapular stabilizer strengthening combined with posterior capsule stretching. If surgery is needed, arthroscopic suture plication with treatment of concomitant lesions has been shown to provide the best clinical outcomes. PMID:24079429

Chambers, Lauchlan; Altchek, David W

2013-10-01

15

Collisionless microinstabilities in stellarators. II. Numerical simulations  

SciTech Connect

Microinstabilities exhibit a rich variety of behavior in stellarators due to the many degrees of freedom in the magnetic geometry. It has recently been found that certain stellarators (quasi-isodynamic ones with maximum-J geometry) are partly resilient to trapped-particle instabilities, because fast-bouncing particles tend to extract energy from these modes near marginal stability. In reality, stellarators are never perfectly quasi-isodynamic, and the question thus arises whether they still benefit from enhanced stability. Here, the stability properties of Wendelstein 7-X and a more quasi-isodynamic configuration, QIPC, are investigated numerically and compared with the National Compact Stellarator Experiment and the DIII-D tokamak. In gyrokinetic simulations, performed with the gyrokinetic code GENE in the electrostatic and collisionless approximation, ion-temperature-gradient modes, trapped-electron modes, and mixed-type instabilities are studied. Wendelstein 7-X and QIPC exhibit significantly reduced growth rates for all simulations that include kinetic electrons, and the latter are indeed found to be stabilizing in the energy budget. These results suggest that imperfectly optimized stellarators can retain most of the stabilizing properties predicted for perfect maximum-J configurations.

Proll, J. H. E.; Xanthopoulos, P.; Helander, P. [Max-Planck-Institut für Plasmaphysik, EURATOM Association, Teilinstitut Greifswald, Wendelsteinstraße 1, 17491 Greifswald, Germany and Max-Planck/Princeton Research Center for Plasma Physics, 17491 Greifswald (Germany)] [Max-Planck-Institut für Plasmaphysik, EURATOM Association, Teilinstitut Greifswald, Wendelsteinstraße 1, 17491 Greifswald, Germany and Max-Planck/Princeton Research Center for Plasma Physics, 17491 Greifswald (Germany)

2013-12-15

16

Comparison of Linear Microinstability Calculations of Varying Input Realism  

SciTech Connect

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.

G. Rewoldt

2003-09-08

17

MICROINSTABILITY OF THE SHOULDER IN THE OVERHEAD ATHLETE  

PubMed Central

The overhead throwing athlete is an extremely challenging patient in sports medicine. The repetitive microtraumatic stresses and extreme ranges of motion observed within the athlete’s shoulder joint complex during the throwing motion constantly place the athlete at risk for injury. While gross instability of the shoulder is possible, microinstability is seen far more frequently and is associated with a variety of different pathologies, including rotator cuff tendonitis, internal impingement, and labral lesions. Treatment of the overhead athlete requires the understanding of several principles based on the unique physical characteristics of this type of athlete and the demands placed upon the static stabilizing structures during the act of throwing. The purpose of this paper is to describe these principles and incorporate them into in a multi?phase progressive rehabilitation program designed to prevent injuries and rehabilitate the injured athlete, both non?operatively and postoperatively. PMID:24175140

Curtis, Alan S.

2013-01-01

18

Particle Simulation of Magnetically Confined Plasmas Princeton Plasma Physics Laboratory  

E-print Network

Particle Simulation of Magnetically Confined Plasmas W. W. Lee Princeton Plasma Physics Laboratory. Lewandowski Beams: H. Qin, R. C. Davidson 1 #12;OUTLINE PPPL ¯ Progress in Particle Simulation ¯ Gyrokinetic Particle Simulation of Microinstabilities ¯ Future of Gyrokinetic Particle Simulation ¯ Particle Simulation

19

A comprehensive gyrokinetic description of global electrostatic microinstabilities in a tokamak  

SciTech Connect

It is believed that low frequency microinstabilities such as ion temperature gradient (ITG) driven modes and trapped electron modes (TEMs) are largely responsible for the experimentally observed anomalous transport via the ion and electron channels in a tokamak. In the present work, a comprehensive global linear gyrokinetic model incorporating fully kinetic (trapped and passing) electrons and ions, actual ion to electron mass ratio, radial coupling, and profile variation is used to investigate the ITG driven modes and pure TEMs. These modes are found to exhibit multiscale structures in the presence of nonadiabatic passing electrons. The multiscale structure is related to the large nonadiabaticity of electrons in the vicinity of mode rational magnetic surfaces and leads to reduced mixing length estimates of transport compared to those obtained from adiabatic electron models.

Chowdhury, J.; Ganesh, R. [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India); Brunner, S.; Vaclavik, J.; Villard, L. [CRPP, Association EURATOM-Confederation Suisse, EPFL, 1015 Lausanne (Switzerland); Angelino, P. [Association Euratom-CEA, CEA/DSM/DRFC, Cadarache, 13108 St. Paul-lez-Durance (France)

2009-05-15

20

Microinstability-based models for confinement properties and ignition criteria in tokamaks  

SciTech Connect

This paper reports on results of theoretical studies dealing with: (1) the use of microinstability-based thermal transport models to interpret the anomalous confinement properties observed in key tokamak experiments such as TFTR and (2) the likely consequences of the presence of such instabilities for future ignition devices. Transport code simulations using profile-consistent forms of anomalous thermal diffusivities due to drift-type instabilities have yielded good agreement with the confinement times and temperatures observed in TFTR under a large variety of operating conditions including pellet-fuelling in both ohmic- and neutral-beam-heated discharges. With regard to achieving an optimal ignition margin, the adverse temperature scaling of anomalous losses caused by drift modes leads to the conclusion that it is best to operate at the maximum allowable density while holding the temperature close to the minimum value required for ignition.

Tang, W.M.; Bishop, C.M.; Coppi, B.; Kaye, S.M.; Perkins, F.W.; Redi, M.H.; Rewoldt, G.

1987-02-01

21

Non-Linear Dynamics and Emergence in Laboratory Fusion Plasmas  

SciTech Connect

Turbulent behaviour of laboratory fusion plasma system is modelled using extended Hasegawa-Wakatani equations. The model is solved numerically using finite difference techniques. We discuss non-linear effects in such a system in the presence of the micro-instabilities, specifically a drift wave instability. We explore particle dynamics in different range of parameters and show that the transport changes from diffusive to non-diffusive when large directional flows are developed.

Hnat, B. [CFSA, Physics Dept., University of Warwick, Coventry (United Kingdom)

2011-09-22

22

Comparing Linear Microinstability of the National Compact Stellarator Expriment and a Shaped Tokamak  

SciTech Connect

One metric for comparing con nement properties of di erent magnetic fusion energy con gurations is the linear critical gradient of drift wave modes. The critical gradient scale length determines the ratio of the core to pedestal temperature when a plasma is limited to marginal stability in the plasma core. The gyrokinetic turbulence code GS2 was used to calculate critical temperature gradients for the linear, collisionless ion tem- perature gradient (ITG) mode in the National Compact Stellarator Experiment (NCSX) and a prototypical shaped tokamak, based on the pro les of a JET H-mode shot and the stronger shaping of ARIES-AT. While a concern was that the narrow cross section of NCSX at some toroidal locations would result in steep gradients that drive instabilities more easily, it is found that other stabilizing e ects of the stellarator con guration o set this so that the normalized critical gradients for NCSX are competitive with or even better than for the tokamak. For the adiabatic ITG mode, NCSX and the tokamak had similar critical gradients, though beyond marginal stability, NCSX had larger growth rates. However, for the kinetic ITG mode, NCSX had a higher critical gradient and lower growth rates until a/LT ?#25; 1:5 a/LT;crit, when it surpassed the tokamak's. A discussion of the results presented with respect to a/LT vs R/LT is included.

J.A. Baumgaertel, G.W. Hammett and D.R. Mikkelsen

2012-11-20

23

Development of gyrotrons for plasma diagnostics (invited)  

NASA Astrophysics Data System (ADS)

Recent advances in high-frequency (>100 GHz) gyrotron technology are reviewed and application to millimeter/submillimeter wave plasma diagnostics is discussed. Gyrotrons have useful capabilities of high-power (>1 kW), long pulse/cw operation, narrow linewidth (<100 kHz), and good spatial mode quality with efficient (˜90%) mode converters. These capabilities could be used to significantly improve collective Thomson scattering diagnostics for the study of instabilities, plasma waves, turbulence, and thermal ion fluctuations. Imaging applications with many detector arrays of plasma density, field direction, and microinstabilities may be possible with gyrotons. In a high-field compact ignition tokamak experiment a possible millimeter wave diagnostics window could be exploited by a gyrotron to measure a number of parameters, including alpha particle density and velocity distribution.

Woskoboinikow, P.

1986-08-01

24

Effect of alpha drift and instabilities on tokamak plasma edge conditions  

SciTech Connect

As suprathermal fusion products slow down in a Tokamak, their average drift is inward. The effect of this drift on the alpha heating and thermalization profiles is examined. In smaller TFTR-type devices, heating in the outer region can be cut in half. Also, the fusion-product energy-distribution near the plasma edge has a positive slope with increasing energy, representing a possible driving mechanism for micro-instabilities. Another instability that can seriously affect outer plasma conditions and shear Alfven transport of alphas is also considered.

Miley, G H; Choi, C K

1983-01-01

25

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

SciTech Connect

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.

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

2014-10-15

26

CONFERENCE DESCRIPTION Theory of Fusion Plasmas: Varenna-Lausanne International Workshop  

NASA Astrophysics Data System (ADS)

The Joint Varenna-Lausanne international workshop on Theory of Fusion Plasmas takes place every other year in a place particularly favourable for informal and in-depth discussions. Invited and contributed papers present state-of-the-art research in theoretical plasma physics, covering all domains relevant to fusion plasmas. This workshop always welcomes a fruitful mix of experienced researchers and students, to allow a better understanding of the key theoretical physics models and applications. Theoretical issues related to burning plasmas Anomalous Transport (Turbulence, Coherent Structures, Microinstabilities) RF Heating and Current Drive Macroinstabilities Plasma-Edge Physics and Divertors Fast particles instabilities Further details: http://Varenna-Lausanne.epfl.ch The conference is organized by: Centre de Recherches en Physique des Plasmas, Ecole Polytechnique Fédérale de Lausanne, Association EURATOM - Confédération Suisse 'Piero Caldirola' International Centre for the Promotion of Science and International School of Plasma Physics Istituto di Fisica del Plasma del CNR, Milano Editors: X Garbet (CEA, Cadarache, France) and O Sauter (CRPP-EPFL, Lausanne, Switzerland)

Garbet, X.; Sauter, O.

2010-12-01

27

Quasilinear Carbon Transport In An Impurity Hole Plasma In LHD  

SciTech Connect

Comprehensive electrostatic gyrokinetic linear stability calculations for ion-scale microinstabilities in an LHD plasma with an ion-ITB and carbon "impurity hole" are used to make quasilinear estimates of particle flux to explore whether microturbulence can explain the observed outward carbon fluxes that flow "up" the impurity density gradient. The ion temperature is not stationary in the ion-ITB phase of the simulated discharge, during which the core carbon density decreases continuously. To fully sample these varying conditions the calculations are carried out at three radial locations and four times. The plasma parameter inputs are based on experimentally measured profiles of electron and ion temperature, as well as electron and carbon density. The spectroscopic line-average ratio of hydrogen and helium densities is used to set the density of these species. Three ion species (H,He,C) and the electrons are treated kinetically, including collisions. Electron instability drive does enhance the growth rate significantly, but the most unstable modes have characteristics of ion temperature gradient (ITG) modes in all cases. As the carbon density gradient is scanned between the measured value and zero, the quasilinear carbon flux is invariably inward when the carbon density profile is hollow, so turbulent transport due to the instabilities considered here does not explain the observed outward flux of impurities in impurity hole plasmas. The stiffness of the quasilinear ion heat flux is found to be 1.7-2.3, which is lower than several estimates in tokamaks.

Mikkelsen, David R. [PPPL; Tanaka, K. [NIFS; Nunami, M. [NIFS; Watanabe, T-H. [Nagoya University; Sugama, H. [NIFS; Yoshinuma, M. [NIFS; Suzuki, Y. [NIFS; Goto, M. [NIFS; Morita, S. [NIFS; Wieland, B. [NIFS; Yamada, I. [NIFS; Yashura, R. [NIFS; Akiyama, T. [NIFS; Pablant, Novimir A. [PPPL

2014-04-01

28

Anomalous transport in toroidal plasmas. Final progress report  

SciTech Connect

Anomalous transport in toroidal plasmas arises from the presence of more complicated magnetic and electric fields than are required by the macroscopic equilibrium of the plasma. If one knew these fields, then the transport coefficients, calculated by classical methods, would be correct except for the direct transport of energy by fields (which is usually considered negligible). The limitation of this procedure is the lack of knowledge of the field perturbations, but there are a number of features that are generally accepted whether the perturbations are due to microinstabilities or due to macroscopic effects such as tearing modes. In particular, the frequencies and the wave numbers of perturbations satisfy {omega}* {approx_lt} {omega}, k{sub {perpendicular}} {rho}{sub i} {approx_lt} 1, and k{sub {parallel}} {rho}{sub i} {much_lt} 1 which imply that the magnetic moments of both the ions and the electrons are conserved and that the particle trajectories obey drift equations. The drift equations imply that if magnetic surfaces exist, particles can cross a surface only if there is a spatial variation in the field strength or the electric potential in the surface. If surfaces fail to exist, then particles can also cross the toroidal flux surfaces by moving along the field lines. Here the authors develop Monte Carlo codes to study anomalous transport in ZT-40 and TOKAPOLE 2.

Punjabi, A.

1992-12-31

29

Currents between tethered electrodes in a magnetized laboratory plasma  

NASA Technical Reports Server (NTRS)

Laboratory experiments on important plasma physics issues of electrodynamic tethers were performed. These included current propagation, formation of wave wings, limits of current collection, nonlinear effects and instabilities, charging phenomena, and characteristics of transmission lines in plasmas. The experiments were conducted in a large afterglow plasma. The current system was established with a small electron-emitting hot cathode tethered to an electron-collecting anode, both movable across the magnetic field and energized by potential difference up to V approx.=100 T(sub e). The total current density in space and time was obtained from complete measurements of the perturbed magnetic field. The fast spacecraft motion was 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 generally 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. The implications of the laboratory observations on electrodynamic tethers in space are discussed.

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

1989-01-01

30

CTR plasma engineering studies  

NASA Astrophysics Data System (ADS)

Research in several areas is reported including: (1) transport in compact tori; (2) bremsstrahlung energy deposition in first wall materials, (3) Coulombic energy transfer collisions; (4) magnetic helicity injection study; (5) blankets for tritium catalyzed deuterium fusion reactors; (6) exploratory studies of applications of optimal control theory; (7) design of a burn dynamic experiment; (8) alpha driven low frequency fast magnetosonic wave microinstability in tandem mirror; (9) fusion product heating and confinement in a tandem mirror; and (10) velocity-space particle loss in field reversed configurations.

Miley, G. H.

31

Sheared Rotation Effects on Kinetic Stability in Enhanced Confinement Tokamak Plasmas, and Nonlinear Dynamics of Fluctuations and Flows in Axisymmetric Plasmas  

SciTech Connect

Sheared rotation dynamics are widely believed to have significant influence on experimentally observed confinement transitions in advanced operating modes in major tokamak experiments, such as the Tokamak Fusion Test Reactor (TFTR) with reversed magnetic shear regions in the plasma interior. The high-n toroidal drift modes destabilized by the combined effects of ion temperature gradients and trapped particles in toroidal geometry can be strongly affected by radially sheared toroidal and poloidal plasma rotation. In previous work with the FULL linear microinstability code, a simplified rotation model including only toroidal rotation was employed, and results were obtained. Here, a more complete rotation model, that includes contributions from toroidal and poloidal rotation and the ion pressure gradient to the total radial electric field, is used for a proper self-consistent treatment of this key problem. Relevant advanced operating mode cases for TFTR are presented. In addition, the complementary problem of the dynamics of fluctuation-driven E x B flow is investigated by an integrated program of gyrokinetic simulation in annulus geometry and gyrofluid simulation in flux tube geometry.

Rewoldt, G.; Beer, M.A.; Chance, M.S.; Hahm, T.S.; Lin, Z.; Tang, W.M. [Princeton Plasma Physics Laboratory, Princeton, NJ 08543 (United States)

1997-12-01

32

Sheared Rotation Effects on Kinetic Stability in Enhanced Confinement Tokamak Plasmas, and Nonlinear Dynamics of Fluctuations and Flows in Axisymmetric Plasmas  

SciTech Connect

Sheared rotation dynamics are widely believed to have signficant influence on experimentally observed confinement transitions in advanced operating modes in major tokamak experiments, such as the Tokamak Fusion Test Reactor (TFTR) [D.J. Grove and D.M. Meade, Nuclear Fusion 25, 1167 (1985)], with reversed magnetic shear regions in the plasma interior. The high-n toroidal drift modes destabilized by the combined effects of ion temperature gradients and trapped particles in toroidal geometry can be strongly affected by radially sheared toroidal and poloidal plasma rotation. In previous work with the FULL linear microinstability code, a simplified rotation model including only toroidal rotation was employed, and results were obtained. Here, a more complete rotation model, that includes contributions from toroidal and poloidal rotation and the ion pressure gradient to the total radial electric field, is used for a proper self-consistent treatment of this key problem. Relevant advanced operating mode cases for TFTR are presented. In addition, the complementary problem of the dynamics of fluctuation-driven E x B flow is investigated by an integrated program of gyrokinetic simulation in annulus geometry and gyrofluid simulation in flux tube geometry.

Beer, M.A.; Chance, M.S.; Hahm, T.S.; Lin, Z.; Rewoldt, G.; Tang, W.M.

1997-11-01

33

Runaway electrons in plasma current sheets  

SciTech Connect

It is shown that a runaway electron population accelerates along the main magnetic field in a Sweet-Parker current sheet. After a characteristic distance the entire current is carried by runaways. The thickness of this runaway sheet is much smaller than the original Ohmic sheet. The influence of microinstabilities is discussed.

Gurevich, A.V.; Sudan, R.N. (Laboratory of Plasma Studies, Cornell University, Ithaca, New York 14853 (United States))

1994-01-31

34

Models of magnetic field evolution and effective viscosity in weakly collisional extragalactic plasmas  

NASA Astrophysics Data System (ADS)

In weakly collisional plasmas such as the intracluster medium (ICM), the viscous stress and the rate of change of the magnetic energy are proportional to the local pressure anisotropy, so subject to constraints imposed by the pressure-anisotropy-driven microinstabilities (mirror and firehose) and controlled by the local instantaneous plasma ?. The dynamics of such plasmas can be dramatically different from a conventional magnetohydrodynamic fluid. The plasma is expected to stay locally marginal with respect to the instabilities, but how it does this remains an open question. Two models of magnetic field evolution are investigated. In the first, marginality is achieved via suppression of the rate of change of the field. In the second, the instabilities give rise to anomalous collisionality, reducing pressure anisotropy to marginal - at the same time decreasing viscosity and so increasing the turbulent rate of strain. Implications of these two models are studied in a simplified zero-dimensional setting. In the first model, the field grows explosively but on a time-scale that scales with the initial ?, while in the second, dynamical field strength can be reached in one large-scale turbulence turnover time regardless of the initial seed. Both models produce very intermittent fields. Both also suffer from fairly strong constraints on their applicability: for typical cluster-core conditions, scale separation between the fluid motions (with account of suppressed viscous stress) and the miscoscale fluctuations break down at ? ˜ 104-105. At larger ? (weaker fields), a fully collisionless plasma dynamo theory is needed to justify field growth from a tiny primordial seed. However, the models discussed here are appropriate for studying the structure of the currently observed field as well as large-scale dynamics and thermodynamics of the magnetized ICM or similarly dilute astrophysical plasmas.

Mogavero, Federico; Schekochihin, Alexander A.

2014-06-01

35

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)

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.

Ahangar, Mahdy; Ebrahimi, Reza; Shams, Mehrzad

2014-10-01

36

Plasma jets and plasma bullets  

Microsoft Academic Search

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

M G Kong; B N Ganguly; R F Hicks

2012-01-01

37

Plasma Medicine  

NASA Astrophysics Data System (ADS)

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.

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

2012-05-01

38

Plasma medicine  

Microsoft Academic Search

Different aspects of plasma medicine, the new branch interdisciplinary between plasma chemistry and medicine, are considered.\\u000a It was shown that complex biological processes in living tissues and bodies can be controlled, stimulated, catalyzed, and\\u000a diagnosed with the use of low-temperature, atmospheric-pressure air plasma. It was found that discharge plasma can produce\\u000a the desired therapeutic effect in wound sterilization and healing,

V. N. Vasilets; A. Gutsol; A. B. Shekhter; A. Fridman

2009-01-01

39

Plasma Physics  

Microsoft Academic Search

Beginning at an introductory level, this text presents a thorough treatment of plasma physics, including an extensive discussion of its applications in thermonuclear fusion research. A novel feature of this book is its comprehensive description of the various concepts and formulas widely used in fusion theory based on the fundamental equations of the plasma fluid. The physics of fusion plasmas

Kyoji Nishikawa; Masashiro Wakatani

1990-01-01

40

Dusty plasmas  

SciTech Connect

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.

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

1996-05-01

41

Plasma valve  

DOEpatents

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.

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

42

Plasma accelerator  

DOEpatents

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.

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

2002-01-01

43

Plasma universe  

NASA Technical Reports Server (NTRS)

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%.

Alfven, H.

1986-01-01

44

Plasma Physics  

NSDL National Science Digital Library

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.

Rack, Philip D.

2012-12-12

45

Plasma Astrophysics  

Microsoft Academic Search

It is well known that most of the matter in the universe is in the plasma state, i.e., it is a fully or partially ionized gas in which electromagnetic interactions between the charged particles play an essential role. Only a very insignificant part of the matter in the universe is in the solid or liquid state. Although not every gas

V. Canuto; C. K. Chou; L. Fassio-Canuto

1978-01-01

46

Plasma Chemistry and Plasma Processing  

Microsoft Academic Search

In nonequilibrium low pressure discharges used in plasma-assisted materials processing, electron impact reactions play an essential role in the gas phase chemistry. The formation, through such collisions, of radical species that react with the substrate surface enables the development of chemical processes where no other technology is available. Integrated circuit fabrication is only one of a wide variety of applications

Amy Wendt

1997-01-01

47

Properties of large scale plasma flow during the early stage of the plasmaspheric refilling  

NASA Technical Reports Server (NTRS)

The objective is to better characterize the macroscopic properties of the interhemisphere plasma flow by solving a more complete set of hydrodynamic equations than that solved previously. Specifically, the ion continuity, momentum and energy equations were solved for the plasma flow along the closed magnetic field lines. During the initial stage of the supersonic outflow in the equatorial region, the ions cool substantially. Using the hydrodynamic model for the large-scale plasma flow, the dynamics of shocks was examined which form in the geomagnetic flux tubes during the early stages of refilling. These shocks are more like those forming in neutral gases than the electrostatic shocks driven by microinstabilities involving ion-ion interaction. Therefore, the shocks seen in the hydrodynamic model are termed as hydrodynamic shocks. Such shocks are generally unsteady and therefore the usual shock jump conditions given by Rankine-Hugoniot relations are not strictly applicable to them. The density, flow velocity and temperature structures associated with the shocks are examined for both asymmetrical and symmetrical flows. In the asymmetrical flow the outflow from one of two conjugate ionospheres is dominant. On the other hand, in the symmetrical case outflows from the two ionospheric sources are identical. Both cases are treated by a two-stream model. In the late type of flow, the early-time refilling shows a relaxation type of oscillation, which is driven by the large-scale interactions between the two identical streams. After this early stage, the resulting temperature structure shows some interesting features. In the equatorial region the streams are isothermal, but in the off-equatorial regions the streams have quite different temperatures, and also densities and flow velocities. The dense and slow stream is found to be warmer than the low-density fast stream. In the late stage of refilling, the temperature is found to steadily increase from the conjugate ionospheres towards the equator; the equatorial temperature is found to be as high as about 8000 K compared to the ionospheric temperature of 3600 K.

Singh, Nagendra; Craven, P.; Torr, D. G.; Richards, P. G.

1990-01-01

48

Study of plasma chemistry and plasma processing  

Microsoft Academic Search

The final technical report describes studies related to plasma chemistry and plasma processing funded by the Office of Naval Research during the period December 15, 1979-June 15, 1983 (Contract: N00014-80-C-0244, NR SRO-016). Two experimental systems needed for a detailed study of plasma etching and plasma deposition of thin films were constructed. A detailed study was made of the plasma processing

H. J. Oskam

1983-01-01

49

Plasma medicine - therapeutic application of physical plasmas  

Microsoft Academic Search

Plasma medicine is an innovative and emerging field combining plasma physics, life science and clinical medicine to use physical\\u000a plasma for therapeutic applications. Initial experiments confirm that plasma can be effective in in vivo antiseptics without affecting surrounding tissue and, moreover, stimulating tissue regeneration. Based on sophisticated basic\\u000a research on plasma-tissue interaction, first therapeutic applications in wound healing, dermatology and

Thomas von Woedtke; Michael Jünger; Thomas Kocher; Axel Kramer; Jürgen Lademann; Ulrike Lindequist; Klaus-Dieter Weltmann

50

Improved plasma accelerator  

NASA Technical Reports Server (NTRS)

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.

Cheng, D. Y.

1971-01-01

51

VOLUME 83, NUMBER 18 P H Y S I C A L R E V I E W L E T T E R S 1 NOVEMBER 1999 Effects of Collisional Zonal Flow Damping on Turbulent Transport  

E-print Network

plasma is believed to arise from electrostatic- pressure-gradient driven microinstabilities [1]. In most simulation [7] results which show that the ion thermal transport from electrostatic ITG turbulence depends

Lin, Zhihong

52

Perspectives on Plasmas  

NSDL National Science Digital Library

Dr. Timothy Eastman developed this website to address aspects of plasma science and technology for the general public and for research and education communities. In the Basics link, users can learn about plasmas and their functions in space, energy, the environment, businesses, governments, and in the home. The Applications link offers many resources about fields of plasma application and institutions involved with plasma technology. Educators can find many images illustrating fusion plasmas, space plasmas, and technology. The site provides a lengthy list of references as well as many helpful links to outside plasma-related educational and research sites.

53

Plasma sweeper. [Patents  

DOEpatents

A device is described for coupling RF power (a plasma sweeper) from RF power introducing means to a plasma having a magnetic field associated therewith comprises at least one electrode positioned near the plasma and near the RF power introducing means. Means are described for generating a static electric field at the electrode directed into the plasma and having a component substantially perpendicular to the plasma magnetic field such that a non-zero vector cross-product of the electric and magnetic fields exerts a force on the plasma causing the plasma to drift.

Motley, R.W.; Glanz, J.

1982-10-25

54

Plasmas for space propulsion  

NASA Astrophysics Data System (ADS)

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.

Ahedo, Eduardo

2011-12-01

55

Industrial plasmas in academia  

NASA Astrophysics Data System (ADS)

The present review, written at the occasion of the 2014 EPS Innovation award, will give a short overview of the research and development of industrial plasmas within the last 30?years and will also provide a first glimpse into future developments of this important topic of plasma physics and plasma chemistry. In the present contribution, some of the industrial plasmas studied at the CRPP/EPFL at Lausanne are highlighted and their influence on modern plasma physics and also discharge physics is discussed. One of the most important problems is the treatment of large surfaces, such as that used in solar cells, but also in more daily applications, such as the packaging industry. In this contribution, the advantages and disadvantages of some of the most prominent plasmas such as capacitively- and inductively-coupled plasmas are discussed. Electromagnetic problems due to the related radio frequency and its consequences on the plasma reactor performance, and also dust formation due to chemical reactions in plasma, are highlighted. Arcing and parasitic discharges occurring in plasma reactors can lead to plasma reactor damages. Some specific problems, such as the gas supply of a large area reactor, are discussed in more detail. Other topics of interest have been dc discharges such as those used in plasma spraying where thermal plasmas are applied for advanced material processing. Modern plasma diagnostics make it possible to investigate sparks in electrical discharge machining, which surprisingly show properties of weakly-coupled plasmas. Nanosecond dielectric barrier discharge plasmas have been applied to more speculative topics such as applications in aerodynamics and will surely be important in the future for ignition and combustion. Most of the commonly-used plasma sources have been shown to be limited in their performance. Therefore new, more effective plasma sources are urgently required. With the recent development of novel resonant network antennas for new advanced large area or large volume plasma sources, an important step towards high performance plasmas and new fast processes is made.

Hollenstein, Ch; Howling, AA; Guittienne, Ph; Furno, I.

2015-01-01

56

International movement of plasma and plasma contracting.  

PubMed

Plasma fractionation is a global business characterised by technological stability, increasing consolidation and a high level of regulatory oversight. All these factors affect the ease with which plasma derivatives can be accessed in the world market. As domestic regulatory measures in the first world blood economies become increasingly resonant to the precautionary approach, the availability of plasma as a raw material, as well as its cost, become an increasingly significant component in the cost of the final product. This decreases the amount of plasma which fractionators are able to allocate for export activities. Also, regulatory standards in the country of manufacture will reflect priorities in that country which may not be similar to those in export markets, but which will affect entry to those markets. While many countries possess a fractionation capacity, the limiting factor in supply worldwide is the amount of plasma available, and nationalistic drivers for each country to have its own plant are inimical to product safety and supply. Rather, the provision of sufficient supplies of domestic plasma should be the focus of resource allocation, with a choice of an appropriate contract fractionator. However, contract fractionation too may be affected by domestic considerations unrelated to the needs of the country of plasma origin. This chapter will review the global plasma market and the influences on plasma and plasma product movement across national borders. Problems in ensuring adequate safety and supply will be identified, and some tentative approaches to the amelioration of current barriers to the provision of plasma derivatives will be outlined. PMID:16050160

Farrugia, A

2005-01-01

57

Plasma Chem Plasma Process 28 (2008):123146  

E-print Network

in "Plasma Chemistry and Plasma Processing 28, 1 (2008) 123--146" DOI : 10.1007/s11090-007-9111 #12; grow Plasma Chem Plasma Process 28 (2008):123­146 DOI 10.1007/s11090-007-9111-1 An Investigation of the Plasma Composition in Plasma- enhanced Hot Filament Catalytic Chemical Vapor Deposition of Carbon

Paris-Sud XI, Université de

58

Basic plasma physics II  

Microsoft Academic Search

The basic physics of classical ideal plasmas is presented in reviews of recent theoretical and experimental investigations, with an emphasis on nonlinear interactions violating the assumptions of weak turbulence. Topics examined include Kolmogorov spectra, parametric instabilities in magnetoactive plasmas, collapse and self-focusing of Langmuir waves, collective dissipation and transport, spontaneous reconnection of magnetic-field lines in a collisionless plasma, collective-beam\\/plasma interaction,

A. A. Galeev; R. N. Sudan

1984-01-01

59

A reconfigurable plasma antenna  

NASA Astrophysics Data System (ADS)

An experiment aimed at investigating the antenna properties of different plasma structures of a plasma column as a reconfigurable plasma antenna, is reported. A 30 cm long plasma column is excited by surface wave, which acts as a plasma antenna. By changing the operating parameters, e.g., working pressure, drive frequency, input power, radius of glass tube, length of plasma column, and argon gas, single plasma antenna (plasma column) can be transformed to multiple small antenna elements (plasma blobs). It is also reported that number, length, and separation between two antenna elements can be controlled by operating parameters. Moreover, experiments are also carried out to study current profile, potential profile, conductivity profile, phase relations, radiation power patterns, etc. of the antenna elements. The effect on directivity with the number of antenna elements is also studied. Findings of the study indicate that entire structure of antenna elements can be treated as a phased array broadside vertical plasma antenna, which produces more directive radiation pattern than the single plasma antenna as well as physical properties and directivity of such antenna can be controlled by operating parameters. The study reveals the advantages of a plasma antenna over the conventional antenna in the sense that different antennas can be formed by tuning the operating parameters.

Kumar, Rajneesh; Bora, Dhiraj

2010-03-01

60

A reconfigurable plasma antenna  

SciTech Connect

An experiment aimed at investigating the antenna properties of different plasma structures of a plasma column as a reconfigurable plasma antenna, is reported. A 30 cm long plasma column is excited by surface wave, which acts as a plasma antenna. By changing the operating parameters, e.g., working pressure, drive frequency, input power, radius of glass tube, length of plasma column, and argon gas, single plasma antenna (plasma column) can be transformed to multiple small antenna elements (plasma blobs). It is also reported that number, length, and separation between two antenna elements can be controlled by operating parameters. Moreover, experiments are also carried out to study current profile, potential profile, conductivity profile, phase relations, radiation power patterns, etc. of the antenna elements. The effect on directivity with the number of antenna elements is also studied. Findings of the study indicate that entire structure of antenna elements can be treated as a phased array broadside vertical plasma antenna, which produces more directive radiation pattern than the single plasma antenna as well as physical properties and directivity of such antenna can be controlled by operating parameters. The study reveals the advantages of a plasma antenna over the conventional antenna in the sense that different antennas can be formed by tuning the operating parameters.

Kumar, Rajneesh [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India); Bora, Dhiraj [ITER Organisation, Cadarache 13108 (France)

2010-03-15

61

Waves in Dusty Plasmas  

Microsoft Academic Search

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

M. Rosenberg

2005-01-01

62

The Plasma Universe  

NASA Astrophysics Data System (ADS)

Preface; 1. The fourth state of matter; 2. The music and dance of plasmas; 3. The Sun-Earth connection; 4. Bringing the Sun to Earth: the story of controlled thermonuclear fusion; 5. The cosmic plasma theater: galaxies, stars, and accretion disks; 6. Putting plasmas to work; Index.

Suplee, Curt

2009-09-01

63

Plasma processing and chemistry  

Microsoft Academic Search

The growing field of applications of plasma as deposition, etching, surface modification and chemical conversion has stimulated a renewed interest in plasma science in the atomic physical chemistry regime. The necessity to optimize the various plasma processing techniques in terms of rates, and material properties has made it mandatory to take a new look at the various processes, as fragmentation,

D C Schram; J A M van der Mullen; M C M van de Sanden

1994-01-01

64

Plasma Treatment of Polymers  

Microsoft Academic Search

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

Jeremy M. Grace; Louis J. Gerenser

2003-01-01

65

Power Exhaust in Fusion Plasmas  

NASA Astrophysics Data System (ADS)

Preface; 1. Introduction; 2. Magnetized plasma physics; 3. Magnetized plasma equilibrium; 4. Magnetized plasma stability; 5. Collisional transport in magnetized plasmas; 6. Turbulent transport in magnetized plasmas; 7. Tokamak plasma boundary and power exhaust; 8. Outlook: power exhaust in fusion reactors; Appendix A. Maxwellian distribution; Appendix B. Curvilinear co-ordinates; References; Index.

Fundamenski, Wojciech

2014-07-01

66

Afterglow Complex Plasma  

SciTech Connect

The review of the first detailed experimental and theoretical studies of complex plasma in RF discharge afterglow is presented. The studies have been done in a frame of FAST collaborative research project between Complex Plasma Laboratory of the University of Sydney and the GREMI laboratory of Universite d'Orleans. We examined the existing models of plasma decay, presents experimental observations of dust dynamics under different afterglow complex plasma conditions, presents the experimental data obtained (in particular the presence of positively charged particles in discharge afterglow), discusses the use of dust particles as a probe to study the diffusion losses in afterglow plasmas.

Samarian, A. A. [School of Physics, University of Sydney, NSW 2006 (Australia); Boufendi, L.; Mikikian, M. [GREMI, CNRS/Universite d'Orleans, 14 rue d'Issoudun, BP6744, 45067 Orleans Cedex 2 (France); Coueedel, L. [School of Physics, University of Sydney, NSW 2006 (Australia); GREMI, CNRS/Universite d'Orleans, 14 rue d'Issoudun, BP6744, 45067 Orleans Cedex 2 (France)

2008-09-07

67

Industrial Plasma Antennas  

NASA Astrophysics Data System (ADS)

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.

Alexeff, Igor

2007-11-01

68

Microwave and RF surface wave sustained discharges as plasma sources for plasma chemistry and plasma processing  

Microsoft Academic Search

The surface wave produced plasma belongs to a class of RF and microwave induced plasmas. It results from the propagation of an electromagnetic wave which uses the plasma column it sustains and the plasma tube as its sole propagating media. This type of plasma offers several advantages compared to the positive column plasma of dc discharges or to other RF

M. Chaker; M. Moisan; Z. Zakrzewski

1986-01-01

69

Plasmas for medicine  

NASA Astrophysics Data System (ADS)

Plasma medicine is an innovative and emerging field combining plasma physics, life science and clinical medicine. In a more general perspective, medical application of physical plasma can be subdivided into two principal approaches. (i) “Indirect” use of plasma-based or plasma-supplemented techniques to treat surfaces, materials or devices to realize specific qualities for subsequent special medical applications, and (ii) application of physical plasma on or in the human (or animal) body to realize therapeutic effects based on direct interaction of plasma with living tissue. The field of plasma applications for the treatment of medical materials or devices is intensively researched and partially well established for several years. However, plasma medicine in the sense of its actual definition as a new field of research focuses on the use of plasma technology in the treatment of living cells, tissues, and organs. Therefore, the aim of the new research field of plasma medicine is the exploitation of a much more differentiated interaction of specific plasma components with specific structural as well as functional elements or functionalities of living cells. This interaction can possibly lead either to stimulation or inhibition of cellular function and be finally used for therapeutic purposes. During recent years a broad spectrum of different plasma sources with various names dedicated for biomedical applications has been reported. So far, research activities were mainly focused on barrier discharges and plasma jets working at atmospheric pressure. Most efforts to realize plasma application directly on or in the human (or animal) body for medical purposes is concentrated on the broad field of dermatology including wound healing, but also includes cancer treatment, endoscopy, or dentistry. Despite the fact that the field of plasma medicine is very young and until now mostly in an empirical stage of development yet, there are first indicators of its enormous economic potential. This ambivalent situation fundamentally requires a responsible use of plasma sources, which are specifically designated for biomedical applications. To enable physicians as well as life scientists to decide whether a given plasma source is really suitable for medical applications or biological experiments, a meaningful and mandatory spectrum of indicators has to be compiled to allow for a basic estimation of the potential of this plasma source.

von Woedtke, Th.; Reuter, S.; Masur, K.; Weltmann, K.-D.

2013-09-01

70

Plasma-maser instability in dusty plasmas  

Microsoft Academic Search

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

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

1993-01-01

71

What is a plasma?  

SciTech Connect

This introduction will define the plasma fourth state of matter, where we find plasmas on earth and beyond, and why they are useful. There are applications to many consumer items, fusion energy, scientific devices, satellite communications, semiconductor processing, spacecraft propulsion, and more. Since 99% of our observable universe is ionized gas, plasma physics determines many important features of astrophysics, space physics, and magnetosphere physics in our solar system. We describe some plasma characteristics, examples in nature, some useful applications, how to create plasmas. A brief introduction to the theoretical framework includes the connection between kinetic and fluid descriptions, quasi neutrality, Debye shielding, ambipolar electric fields, some plasma waves. Hands-on demonstrations follow. More complete explanations will follow next week.

Intrator, Thomas P. [Los Alamos National Laboratory

2012-08-30

72

Space plasma physics research  

NASA Technical Reports Server (NTRS)

During the course of this grant, work was performed on a variety of topics and there were a number of significant accomplishments. A summary of these accomplishments is included. The topics studied include empirical model data base, data reduction for archiving, semikinetic modeling of low energy plasma in the inner terrestrial magnetosphere and ionosphere, O(+) outflows, equatorial plasma trough, and plasma wave ray-tracing studies. A list of publications and presentations which have resulted from this research is also included.

Comfort, Richard H.; Horwitz, James L.

1993-01-01

73

Classical and quantum plasmas  

Microsoft Academic Search

A brief survey is given of the different theoretical approaches to the study of the low-density, high-temperature `classical' plasma and of the high-density, low-temperature `quantum' plasma. The random phase approximation, collective-variables method is shown to yield the same result as the collisionless Boltzmann equation combined with the self-consistent field method. Dynamic behaviour is studied in the classical plasma, with particular

D. Pines

1961-01-01

74

Pilot Plasma Engine  

NASA Technical Reports Server (NTRS)

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.

1961-01-01

75

Solid expellant plasma generator  

NASA Technical Reports Server (NTRS)

An improved solid expellant plasma generator has been developed. The plasma generator includes a support housing, an electrode rod located in the central portion of the housing, and a mass of solid expellant material that surrounds the electrode rod within the support housing. The electrode rod and the solid expellant material are made of separate materials that are selected so that the electrode and the solid expellant material decompose at the same rate when the plasma generator is ignited. This maintains a point of discharge of the plasma at the interface between the electrode and the solid expellant material.

Stone, Nobie H. (Inventor); Poe, Garrett D. (Inventor); Rood, Robert (Inventor)

2010-01-01

76

Planetary plasma waves  

NASA Technical Reports Server (NTRS)

The primary types of plasma waves observed in the vicinity of the planets Venus, Mars, Earth, Jupiter, Saturn, Uranus, and Neptune are described. The observations are organized according to the various types of plasma waves observed, ordered according to decreasing distance from the planet, starting from the sunward side of the planet, and ending in the region near the closest approach. The plasma waves observed include: electron plasma oscillations and ion acoustic waves; trapped continuum radiation; electron cyclotron and upper hybrid waves; whistler-mode emissions; electrostatic ion cyclotron waves; and electromagnetic ion cyclotron waves.

Gurnett, Donald A.

1993-01-01

77

Princeton Plasma Physics Laboratory  

SciTech Connect

This report discusses the following topics: principal parameters achieved in experimental devices fiscal year 1990; tokamak fusion test reactor; compact ignition tokamak; Princeton beta experiment- modification; current drive experiment-upgrade; international collaboration; x-ray laser studies; spacecraft glow experiment; plasma processing: deposition and etching of thin films; theoretical studies; tokamak modeling; international thermonuclear experimental reactor; engineering department; project planning and safety office; quality assurance and reliability; technology transfer; administrative operations; PPPL patent invention disclosures for fiscal year 1990; graduate education; plasma physics; graduate education: plasma science and technology; science education program; and Princeton Plasma Physics Laboratory reports fiscal year 1990.

Not Available

1990-01-01

78

Wakes in inhomogeneous plasmas  

NASA Astrophysics Data System (ADS)

The Debye shielding of a charge immersed in a flowing plasma is an old classic problem. It has been given renewed attention in the last two decades in view of experiments with complex plasmas, where charged dust particles are often levitated in a region with strong ion flow. Efforts to describe the shielding of the dust particles in such conditions have been focused on the homogeneous plasma approximation, which ignores the substantial inhomogeneity of the levitation region. We address the role of the plasma inhomogeneity by rigorously calculating the point charge potential in the collisionless Bohm sheath. We demonstrate that the inhomogeneity can dramatically modify the wake, making it nonoscillatory and weaker.

Kompaneets, Roman; Ivlev, Alexei V.; Nosenko, Vladimir; Morfill, Gregor E.

2014-04-01

79

Plasma waves at Venus  

NASA Astrophysics Data System (ADS)

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.

Strangeway, R. J.

1991-02-01

80

EDITORIAL: Plasma jets and plasma bullets Plasma jets and plasma bullets  

NASA Astrophysics Data System (ADS)

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

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

2012-06-01

81

Interplanetary medium dust - dusty plasma ?  

Microsoft Academic Search

Measurements from spacecraft provide the only opportunity for in-situ studies of cosmic dusty plasmas and the most extended target for measurements is the interplanetary medium filled with cosmic dust and solar wind plasma Though the interplanetary medium does not provide a dusty plasma according to its proper definition dusty plasma conditions may locally apply Moreover dust plasma interactions in the

I. Mann

2006-01-01

82

Partially ionized plasmas, including the Third Symposium on Uranium Plasmas  

NASA Technical Reports Server (NTRS)

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.

Krishnan, M.

1976-01-01

83

Hybrid plume plasma rocket  

NASA Technical Reports Server (NTRS)

A technique for producing thrust by generating a hybrid plume plasma exhaust is disclosed. A plasma flow is generated and introduced into a nozzle which features one or more inlets positioned to direct a flow of neutral gas about the interior of the nozzle. When such a neutral gas flow is combined with the plasma flow within the nozzle, a hybrid plume is constructed including a flow of hot plasma along the center of the nozzle surrounded by a generally annular flow of neutral gas, with an annular transition region between the pure plasma and the neutral gas. The temperature of the outer gas layer is below that of the pure plasma and generally separates the pure plasma from the interior surfaces of the nozzle. The neutral gas flow both insulates the nozzle wall from the high temperatures of the plasma flow and adds to the mass flow rate of the hybrid exhaust. The rate of flow of neutral gas into the interior of the nozzle may be selectively adjusted to control the thrust and specific impulse of the device.

Chang, Franklin R. (inventor)

1989-01-01

84

Pulsed Plasma Thruster  

NASA Technical Reports Server (NTRS)

Dr. Tom Markusic, a propulsion research engineer at the Marshall Space Flight Center (MSFC), adjusts a diagnostic laser while a pulsed plasma thruster (PPT) fires in a vacuum chamber in the background. NASA/MSFC's Propulsion Research Center (PRC) is presently investigating plasma propulsion for potential use on future nuclear-powered spacecraft missions, such as human exploration of Mars.

2002-01-01

85

Fundamentals of Plasma Physics  

E-print Network

Fundamentals of Plasma Physics James D. Callen University of Wisconsin, Madison June 28, 2006 #12;PREFACE Plasma physics is a relatively new branch of physics that became a mature science over the last half of the 20th century. It builds on the fundamental areas of classical physics: mechanics

Callen, James D.

86

Plasma technology directory  

SciTech Connect

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.

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

1995-03-01

87

Plasma processing and chemistry  

Microsoft Academic Search

Plasma deposition and plasma conversion can be characterized by five steps: pro- duction by ionization, transfer of chemistry to precursors, transport of radicals to the surface, surface interactions with deposition, recirculation and generation of new monomers. For very fast deposition, large flows of radicals are needed and a regime is reached, in which mono- layer coverage is reached in a

Daniel C. Schram

2002-01-01

88

Plasmas via computer simulations  

Microsoft Academic Search

One of the behaviors of plasma is that they sometimes act like a collection of individual particles. Our purpose was to study how one charged particle in plasma behaves in a self-consistent electric field and external uniform magnetic field. We did this by setting up a self-consistent algorithm that given initial position and velocity coordinates of an ion, calculates the

Victor Bautista; Andrew Wallace

2007-01-01

89

Focus on Plasma Medicine  

Microsoft Academic Search

Plasma Healthcare’ is an emerging interdisciplinary research topic of rapidly growing importance, exploring considerable opportunities at the interface of plasma physics, chemistry and engineering with life sciences. Some of the scientific discoveries reported so far have already demonstrated clear benefits for healthcare in areas of medicine, food safety, environmental hygiene, and cosmetics. Examples include ongoing studies of prion inactivation, chronic

G E Morfill; M G Kong; J L Zimmermann

2009-01-01

90

Ablation plasma ion implantation  

Microsoft Academic Search

The novel hybrid technique, Ablation Plasma Ion Implantation (APII), has been characterized and optimized for ion implantation and\\/or thin film deposition. In APII, a solid target is ablated by a laser; the resulting plasma plume is the source of ions, which are accelerated to high energy by a negative bias voltage imposed on the substrate. The ions are implanted into

Bo Qi

2002-01-01

91

Diamagnetism of rotating plasma  

SciTech Connect

Diamagnetism and magnetic measurements of a supersonically rotating plasma in a shaped magnetic field demonstrate confinement of plasma pressure along the magnetic field resulting from centrifugal force. The Grad-Shafranov equation of ideal magnetohydrodynamic force balance, including supersonic rotation, is solved to confirm that the predicted angular velocity is in agreement with spectroscopic measurements of the Doppler shifts.

Young, W. C.; Hassam, A. B.; Romero-Talamas, C. A.; Ellis, R. F.; Teodorescu, C. [IREAP, University of Maryland, College Park, Maryland 20742 (United States)

2011-11-15

92

Planet -Star Plasma Interactions  

E-print Network

Planet - Star Plasma Interactions Philippe Zarka LESIA, Observatoire de Paris/CNRS, Meudon philippe.zarka@obspm.fr References : · Zarka, P., Plasma interactions of exoplanets with their parent star and associated radio emissions, Planet. Space Sci., 55, 598-617, 2007. · Griessmeier, J.-M., P. Zarka and H. Spreeuw, Predicting

Demoulin, Pascal

93

Plasma motor generator system  

Microsoft Academic Search

The significant potential advantages of a plasma motor generator system over conventional systems for the generation of electrical power and propulsion for spacecraft in low Earth orbits warrants its further investigation. The two main components of such a system are a long insulated wire and the plasma generating hollow cathodes needed to maintain electrical contact with the ionosphere. Results of

Gerald E. Hite

1987-01-01

94

Plasma engineering for MARS  

SciTech Connect

The two-year Mirror Advanced Reactor Study (MARS) has resulted in the conceptual design of a commercial, electricity-producing fusion reactor based on tandem mirror confinement. The physics basis for the MARS reactor was developed through work in two highly coupled areas of plasma engineering: magnetics and plasma performance.

Carlson, G.A.; Baldwin, D.E.; Barr, W.L.

1983-03-24

95

Triggered plasma opening switch  

DOEpatents

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.

Mendel, Clifford W. (Albuquerque, NM)

1988-01-01

96

Plasma opening switch  

DOEpatents

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.

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

2001-01-01

97

Wakes in inhomogeneous plasmas  

E-print Network

The Debye shielding of a charge immersed in a flowing plasma is an old classic problem in plasma physics. It has been given renewed attention in the last two decades in view of experiments with complex plasmas, where charged dust particles are often levitated in a region with strong ion flow. Efforts to describe the shielding of the dust particles in such conditions have been focused on the homogeneous plasma approximation, which ignores the substantial inhomogeneity of the levitation region. We address the role of the plasma inhomogeneity by rigorously calculating the point charge potential in the collisionless Bohm sheath. We demonstrate that the inhomogeneity can dramatically modify the wake, making it non-oscillatory and weaker.

Kompaneets, Roman; Nosenko, Vladimir; Morfill, Gregor E

2014-01-01

98

Solar system plasma waves  

NASA Technical Reports Server (NTRS)

An overview is given of spacecraft observations of plasma waves in the solar system. In situ measurements of plasma phenomena have now been obtained at all of the planets except Mercury and Pluto, and in the interplanetary medium at heliocentric radial distances ranging from 0.29 to 58 AU. To illustrate the range of phenomena involved, we discuss plasma waves in three regions of physical interest: (1) planetary radiation belts, (2) planetary auroral acceleration regions and (3) the solar wind. In each region we describe examples of plasma waves that are of some importance, either due to the role they play in determining the physical properties of the plasma, or to the unique mechanism involved in their generation.

Gurnett, Donald A.

1995-01-01

99

Plasma electrolysis for surface engineering  

Microsoft Academic Search

This paper overviews the relatively new surface engineering discipline of plasma electrolysis, the main derivative of this being plasma electrolytic deposition (PED), which includes techniques such as plasma electrolytic oxidation (PEO) and plasma electrolytic saturation (PES) processes such as plasma electrolytic nitriding\\/carburizing (PEN\\/PEC). In PED technology, spark or arc plasma micro-discharges in an aqueous solution are utilised to ionise gaseous

A. L. Yerokhin; X. Nie; A. Leyland; A. Matthews; S. J. Dowey

1999-01-01

100

Plasma sheath criterion in thermal electronegative plasmas  

SciTech Connect

The sheath formation criterion in electronegative plasma is examined. By using a multifluid model, it is shown that in a collisional sheath there will be upper as well as lower limits for the sheath velocity criterion. However, the parameters of the negative ions only affect the lower limit.

Ghomi, Hamid [Laser and Plasma Research Institute, Shahid Beheshti University, Evin 1983963113, Tehran (Iran, Islamic Republic of); Khoramabadi, Mansour; Ghorannevis, Mahmod [Plasma Physics Research Center, Science and Research Campus of Islamic Azad University, P.O. Box 14665-678, Tehran (Iran, Islamic Republic of); Shukla, Padma Kant [Institut fuer Theoretische Physik IV, Fakultaet fuer Physik und Astronomie, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany)

2010-09-15

101

Dense Hypervelocity Plasma Jets  

NASA Astrophysics Data System (ADS)

We are developing high velocity dense plasma jets for fusion and HEDP applications. Traditional coaxial plasma accelerators suffer from the blow-by instability which limits the mass accelerated to high velocity. In the current design blow-by is delayed by a combination of electrode shaping and use of a tailored plasma armature created by injection of a high density plasma at a few eV generated by arrays of capillary discharges or sparkgaps. Experimental data will be presented for a complete 32 injector gun system built for driving rotation in the Maryland MCX experiment, including data on penetration of the plasma jet through a magnetic field. We present spectroscopic measurements of plasma velocity, temperature, and density, as well as total momentum measured using a ballistic pendulum. Measurements are in agreement with each other and with time of flight data from photodiodes and a multichannel PMT. Plasma density is above 10^15 cm-3, velocities range up to about 100 km/s. Preliminary results from a quadrature heterodyne HeNe interferometer are consistent with these results.

Case, Andrew; Witherspoon, F. Douglas; Messer, Sarah; Bomgardner, Richard; Phillips, Michael; van Doren, David; Elton, Raymond; Uzun-Kaymak, Ilker

2007-11-01

102

Origins of magnetospheric plasma  

SciTech Connect

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.

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

1991-01-01

103

Plasma diagnostics in plasma processing for nanotechnology and nanolevel chemistry  

Microsoft Academic Search

The author reviews the role of various plasma diagnostics in plasma processing for nanotechnology, and points out some essential methods of spectroscopic methods to diagnose plasmas for nanoprocessing. Two experimental examples are discussed between the characteristics of nanomaterials and plasma parameters. One is measurement of rotation temperature in processing of carbon nanotube. The other is that of vibrational temperature in

Hiroshi Akatsuka

2004-01-01

104

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

E-print Network

Plasma-Therm Workshop: Fundamentals of Plasma Processing (Etching & Deposition) Nanofabrication of lithography, photochemistry, x-ray mask fabrication, PVD, and plasma processing. During his 15+ years of plasma processing for R&D, MEMS, photonics, data storage, power, and compound semiconductor applications

Martin, Jan M.L.

105

Plasma Chemical Aspects Of Dust Formation In Hydrocarbon Plasmas  

SciTech Connect

This contribution deals with some plasma chemical aspects of dust formation in hydrocarbon plasmas. The interplay between dust formation and plasma chemistry will be discussed by means of different experimental results. One specific example concerns the formation of benzene and the role of atomic hydrogen for plasma chemical processes and dust formation in hydrocarbon discharges.

Berndt, J.; Kovacevic, E. [GREMI, Universite d'Orleans, Polytech' Orleans, 14 rue d'Issoudun, B. P. 6744, 45067 ORLEANS Cedex 2 (France); Stepanovic, O.; Stefanovic, I.; Winter, J. [Ruhr-University Bochum, Institute for Experimental Physics II, D-44780 Bochum (Germany)

2008-09-07

106

Azimuthal plasma pressure gradient in quiet time plasma sheet  

Microsoft Academic Search

We have investigated the quiet-time azimuthal plasma pressure gradient in the plasma sheet at a radial distance of 10 RE to 12 RE using two THEMIS spacecraft that were in overlapping orbits during the 2008 THEMIS tail season. The equatorial plasma pressure is estimated by using the in-situ measurement of the plasma pressure and magnetic pressure based on pressure balance

X. Xing; L. R. Lyons; V. Angelopoulos; D. Larson; J. McFadden; C. Carlson; A. Runov; U. Auster

2009-01-01

107

Plasma spraying of alumina: Plasma and particle flow fields  

Microsoft Academic Search

A comprehensive experimental examination of the interaction between a subsonic thermal plasma jet and injected alumine, particles is presented. Measurements of plasma velocity, temperature, and entrained air were obtained from an enthalpy probe and mass spectrometer combination. A diffusive separation, or demixing, of the Ar and He plasma gas was observed. Centerline plasma velocities and temperatures ranged from 1501500 m\\/s

J. R. Fincke; W. D. Swank; D. C. Haggard

1993-01-01

108

Measuring the Plasma Density of a Ferroelectric Plasma Source in an Expanding Plasma  

SciTech Connect

The initial density and electron temperature at the surface of a ferroelectric plasma source were deduced from floating probe measurements in an expanding plasma. The method exploits negative charging of the floating probe capacitance by fast flows before the expanding plasma reaches the probe. The temporal profiles of the plasma density can be obtained from the voltage traces of the discharge of the charged probe capacitance by the ion current from the expanding plasma. The temporal profiles of the plasma density, at two different distances from the surface of the ferroelectric plasma source, could be further fitted by using the density profiles for the expanding plasma. This gives the initial values of the plasma density and electron temperature at the surface. The method could be useful for any pulsed discharge, which is accompanied by considerable electromagnetic noise, if the initial plasma parameters might be deduced from measurements in expanding plasma.

A. Dunaevsky; N.J. Fisch

2003-10-02

109

Atmospheric pressure plasmas: A review  

Microsoft Academic Search

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

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

2006-01-01

110

PLASMA PHYSICS PPPL UC Davis  

E-print Network

PRINCETON PLASMA PHYSICS LABORATORY PPPL UC Davis PRINCETON PLASMA PHYSICS LABORATORY PPPL UC Davis Scattering System for ETG physics on NSTX H. Park, E. Mazzucato, and D. Smith PPPL, Princeton University C, 2006 Hyatt Regency, Dallas, TX #12;PRINCETON PLASMA PHYSICS LABORATORY PPPL UC Davis PRINCETON PLASMA

111

Inductively coupled helium plasma torch  

DOEpatents

An inductively coupled plasma torch including a base member, a plasma tube and a threaded insert member within the plasma tube for directing the plasma gas in a tangential flow pattern. The design of the torch eliminates the need for a separate coolant gas tube. The torch can be readily assembled and disassembled with a high degree of alignment accuracy.

Montaser, Akbar (Potomac, MD); Chan, Shi-Kit (Washington, DC); Van Hoven, Raymond L. (Alexandria, VA)

1989-01-01

112

Spatially extended atmospheric plasma arrays  

Microsoft Academic Search

This paper reports a systematic study of spatially extended atmospheric plasma (SEAP) arrays employing many parallel plasma jets packed densely and arranged in an honeycomb configuration. The work is motivated by the challenge of using inherently small atmospheric plasmas to address many large-scale processing applications including plasma medicine. The first part of the study considers a capillary-ring electrode configuration as

Z. Cao; Q. Nie; D. L. Bayliss; J. L. Walsh; C. S. Ren; D. Z. Wang; M. G. Kong

2010-01-01

113

Plasma-based accelerator structures  

SciTech Connect

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.

Schroeder, Carl B.

1999-12-01

114

Simulation of Fusion Plasmas  

ScienceCinema

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.

Chris Holland

2010-01-08

115

Wakes in inhomogeneous plasmas.  

PubMed

The Debye shielding of a charge immersed in a flowing plasma is an old classic problem. It has been given renewed attention in the last two decades in view of experiments with complex plasmas, where charged dust particles are often levitated in a region with strong ion flow. Efforts to describe the shielding of the dust particles in such conditions have been focused on the homogeneous plasma approximation, which ignores the substantial inhomogeneity of the levitation region. We address the role of the plasma inhomogeneity by rigorously calculating the point charge potential in the collisionless Bohm sheath. We demonstrate that the inhomogeneity can dramatically modify the wake, making it nonoscillatory and weaker. PMID:24827356

Kompaneets, Roman; Ivlev, Alexei V; Nosenko, Vladimir; Morfill, Gregor E

2014-04-01

116

Understanding Micro Plasmas  

E-print Network

Micro plasmas are operated around atmospheric pressure exhibiting pronounced non-equilibrium characteristics, i.e. they possess energetic electrons while ions and neutrals remain cold. They have gained significant interest due to their enormous application potential e.g. in the biomedical, surface modification and light source areas, just to name a few. Many different configurations are in use. Their understanding and quantification is mandatory for further progress in applications. We report on recent progress in the diagnostics and simulation of the entire micro plasma system from gas introduction, via the plasma discharge up to the samples at the example of a plasma jet operated in He/O2 in an ambient air environment.

Winter, J; Böke, M; Ellerweg, D; Hemke, T; Knake, N; Mussenbrock, T; Niermann, B; Schröder, D; der Gathen, V Schulz-von; von Keudell, A

2011-01-01

117

Fizeau plasma interferometer  

SciTech Connect

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)

Frank, A.M.

1980-01-01

118

Implantation-plasma nitriding  

NASA Astrophysics Data System (ADS)

Martensite steel 0.5Cr12Ni2MoMgMn and titanium alloy TiMo1Zr4.5Sn3 were nitrided by high intensity nitrogen plasma bombardment (current densities were 3·1016 cm-2s-1 and 1.2·1017cm-2s-1 for martensite steel and titanium alloy correspondingly). Preliminary 30-keV N+2 ion implantation and subsequent plasma treatment essentially increases N penetration depth two orders of magnitude and surface hardness by a factor ˜3. Approximately the same effect was received also at low energy (300eV) and high intensity Ar+ ion prebombardment and subsequent nitrogen plasma treatment. Near the surface a X-ray amorphous layer is created as a result of implantation-plasma treatment. High dose implanted atoms penetration is explained by their repulsive interaction and diffusion along dislocations.

Guseva, M. I.; Gordeeva, G. V.; Martynenko, Yu. V.; Atamanov, M. V.; Neumoin, V. E.; Smyslov, A. M.

119

CRRES plasma wave experiment  

NASA Astrophysics Data System (ADS)

The CRRES plasma wave experiment is designed to provide information on the plasma wave environment and the total plasma density in the Earth's radiation belts and throughout the CRRES orbit. This information is valuable both for studying the naturally occurring wave-particle interactions affecting the plasma and particle environment in the plasmasphere and magnetosphere as well as for studying the chemical releases. The electric field sensors for this instrument consist of two long electric dipole antennas (about 100 m tip-to-tip), and the magnetic field sensor is a search coil magnetometer mounted at the end of a 6-m boom. The instrument has a 14-channel spectrum analyzer covering the frequency range from 5.6 Hz to 10 kHz, and a 128-step sweep frequency receiver covering the frequency range from 100 Hz to 400 kHz.

Anderson, Roger R.; Gurnett, Donald A.; Odem, Daniel L.

1992-08-01

120

Induction plasma tube  

DOEpatents

An induction plasma tube having a segmented, fluid-cooled internal radiation shield is disclosed. The individual segments are thick in cross-section such that the shield occupies a substantial fraction of the internal volume of the plasma enclosure, resulting in improved performance and higher sustainable plasma temperatures. The individual segments of the shield are preferably cooled by means of a counterflow fluid cooling system wherein each segment includes a central bore and a fluid supply tube extending into the bore. The counterflow cooling system results in improved cooling of the individual segments and also permits use of relatively larger shield segments which permit improved electromagnetic coupling between the induction coil and a plasma located inside the shield. Four embodiments of the invention, each having particular advantages, are disclosed.

Hull, Donald E. (Los Alamos, NM)

1984-01-01

121

Induction plasma tube  

DOEpatents

An induction plasma tube having a segmented, fluid-cooled internal radiation shield is disclosed. The individual segments are thick in cross-section such that the shield occupies a substantial fraction of the internal volume of the plasma enclosure, resulting in improved performance and higher sustainable plasma temperatures. The individual segments of the shield are preferably cooled by means of a counterflow fluid cooling system wherein each segment includes a central bore and a fluid supply tube extending into the bore. The counterflow cooling system results in improved cooling of the individual segments and also permits use of relatively larger shield segments which permit improved electromagnetic coupling between the induction coil and a plasma located inside the shield. Four embodiments of the invention, each having particular advantages, are disclosed.

Hull, D.E.

1982-07-02

122

Plasma jet effects on the ionospheric plasma  

NASA Technical Reports Server (NTRS)

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.

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

1983-01-01

123

Plasma Screen Floating Mount  

DOEpatents

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.

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

2004-10-26

124

Plasmas in Saturn's magnetosphere  

NASA Technical Reports Server (NTRS)

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.

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

1980-01-01

125

Condensed Plasmas under Microgravity  

Microsoft Academic Search

Experiments under microgravity conditions were carried out to study ``condensed'' (liquid and crystalline) states of a colloidal plasma (ions, electrons, and charged microspheres). Systems with ~106 microspheres were produced. The observed systems represent new forms of matter-quasineutral, self-organized plasmas-the properties of which are largely unexplored. In contrast to laboratory measurements, the systems under microgravity are clearly three dimensional (as expected);

G. E. Morfill; H. M. Thomas; U. Konopka; H. Rothermel; M. Zuzic; A. Ivlev; J. Goree

1999-01-01

126

Plasmas in Saturn's magnetosphere  

Microsoft Academic Search

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

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

1980-01-01

127

[Plasma hypertonicity in children].  

PubMed

The plasma hypertonicity is a severe and quite frequent disorder in children. The most frequent causes are hypernatremia related conditions, even though other causes of hyperosmolarity, such as hyperglycaemia and exogenous solutes accumulation also occur. The management and treatment of this condition is delicate and requires a thorough understanding of the underlying hydro electrolytic disorder. The authors perform a theoretical review of plasma hypertonicity in children, focusing on the three most frequent associated conditions: hypernatremic dehydration, salt poisoning and hyperosmolar coma. PMID:20654264

Teixeira, Ana; Ribeiro, Augusto

2010-01-01

128

Plasma tomography systems for industrial plasma tools  

SciTech Connect

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.

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

129

Plasma scattering of electromagnetic radiation  

Microsoft Academic Search

The scattered power spectrum is considered along with aspects of incoherent scattering, constraints on scattering experiments, optical systems, the theory concerning the scattered spectrum for a low-temperature plasma, and questions of scattering from a low-temperature stable plasma. Attention is also given to scattering from a magnetized plasma, scattering from a high-temperature plasma, scattering from unstable plasmas, the kinetic theory of

J. Sheffield

1975-01-01

130

Plasma plume propagation characteristics of pulsed radio frequency plasma jet  

SciTech Connect

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.

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

131

Plasma coal reprocessing  

NASA Astrophysics Data System (ADS)

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.

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

2013-12-01

132

DC Dusty Plasma Simulation  

NASA Astrophysics Data System (ADS)

We describe the development of simulations of a complex plasma-composed of a low-temperature plasma and dust grains-to be used in comparing the electron, dust and ion interactions in the simulations to the Dusty Plasma eXperiments (DPX) being conducted at the Princeton Plasma Physics Laboratory (PPPL). There are two DPX experiments: a ground-based experiment used to investigate the spontaneous formation of dust acoustic waves and the flight-based experiment that has gone on three flights on NASA's ``Weightless Wonder.'' The latter experiment has recently been outfitted with a thermal heater used to generate a thermal gradient in the device. This thermal gradient produces a thermophoretic force on the charged dust grains that counteracts gravity, thereby simulating the flights on the ``Weightless Wonder.'' We have modified the XOOPIC code (J.P. Verboncoeur et al., Comp. Phys. Comm., 87, May 11, 1995, pp. 199-211) to simulate the DPX apparatuses by adding a new dielectric particle species and creating additional modules to handle dust by allowing variable charge and deposition currents during the collision phase of the code. Using these simulations, plasma dynamics and dust cloud characteristics are compared with experimental results (C. Udemgba, these proceedings).

Blumenkopf, Joshua; Wissel, Stephanie; Zwicker, Andrew

2011-11-01

133

Nanoparticle-Plasma Interactions in Dusty Argon-Hydrogen Plasmas  

NASA Astrophysics Data System (ADS)

We studied the role of hydrogen in altering the plasma-nanoparticle interactions in low pressure dusty Ar-H2 plasma. Most dusty plasmas in which particles form through chemical nucleation, are multi-component plasmas containing hydrogen. As hydrogen's ionization potential is close to that of argon, both gases may be ionized. The presence of the light mass hydrogen ions has the potential to modify the plasma and plasma-nanoparticle interactions. We developed a global model for dusty argon-hydrogen plasma. For given absorbed power, nanoparticle density, pressure, and chamber size, we solved the power balance, plasma species balance, and particle current balance equations. We included a system of rate equations for important argon-hydrogen plasma chemical reactions and obtained electron energy distribution function (EEDF) using ZDPlasKin. A trace amount of H2 gas in Ar discharge causes Ar^+, ArH^+, and H3^+ to be the dominant ions. Their relative densities are dependent on chamber pressure, gas composition, and the nanoparticle density. Increase in H2 gas fraction reduces the plasma density. The presence of light ions reduces the average particle charge. Electron collisions with hydrogen and with the nanoparticles affect the EEDF shape. Overall, we find that the presence of H2 in the discharge significantly alters the plasma properties and the fundamental plasma-nanoparticle interactions. This work was supported by the US Dept. of Energy Plasma Science Center and DOE grant DE/SC-0002391.

Kortshagen, Uwe; Mamunuru, Meenakshi

2012-10-01

134

Plasma effects on subcellular structures  

SciTech Connect

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.

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

135

Pulsed Plasma Accelerator Modeling  

NASA Technical Reports Server (NTRS)

This report presents the main results of the modeling task of the PPA project. The objective of this task is to make major progress towards developing a new computational tool with new capabilities for simulating cylindrically symmetric 2.5 dimensional (2.5 D) PPA's. This tool may be used for designing, optimizing, and understanding the operation of PPA s and other pulsed power devices. The foundation for this task is the 2-D, cylindrically symmetric, magnetohydrodynamic (MHD) code PCAPPS (Princeton Code for Advanced Plasma Propulsion Simulation). PCAPPS was originally developed by Sankaran (2001, 2005) to model Lithium Lorentz Force Accelerators (LLFA's), which are electrode based devices, and are typically operated in continuous magnetic field to the model, and implementing a first principles, self-consistent algorithm to couple the plasma and power circuit that drives the plasma dynamics.

Goodman, M.; Kazeminezhad, F.; Owens, T.

2009-01-01

136

Active plasma experiments  

NASA Astrophysics Data System (ADS)

Plasma injection experiments involve generation of luminous plasma clouds by injection, in the near-earth space, of visible tracers of plasma transport, such as Ba, Eu, or Li metal vapors, which are subsequently ionized by solar UV radiation. This paper discusses the technique involved in the Ba-release experiments and the results of some of its applications, with particular attention given to the AMPTE artificial comet experiment in which about 2 kg of Ba vapor were released outside the earth's magnetic field. The AMPTE's two satellites carried instruments for measuring and analyzing the magnetic field, electric and magnetic wave fields over many decades of frequency, the velocity distributions of ions and electrons, as well as the charge, mass, and energy distributions of energetic ions. These measurements were complemented by optical observations from aircraft and on the ground.

Haerendel, Gerhard

137

Large area plasma source  

NASA Technical Reports Server (NTRS)

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.

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

2008-01-01

138

Plasma Simulation Program  

SciTech Connect

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.

Greenwald, Martin

2011-10-04

139

Plasma contactor research, 1990  

NASA Technical Reports Server (NTRS)

Emissive and Langmuir probes were used to measure plasma potential profiles, plasma densities, electron energy distributions, and plasma noise levels near a hollow cathode-based plasma contactor emitting electrons. The effects of electron emission current (100 to 1500 mA) and contactor flowrate (2 to 10 sccm (Xenon)) on these data are examined. Retarding potential analyzer (RPA) measurements showing that high energy ions generally stream from a contactor along with the electrons being emitted are also presented, and a mechanism by which this occurs is postulated. This mechanism, which involves a high rate of ionization induced between electrons and atoms flowing together from the hollow cathode orifice, results in a region of high positive space charge and high positive potential. Langmuir and RPA probe data suggests that both electrons and ions expand spherically from this potential hill region. In addition to experimental observations, a simple one-dimensional model which describes the electron emission process and predicts the phenomena just mentioned is presented and is shown to agree qualitatively with these observations. Experimental results of the first stage of bilateral cooperation with the Italian Institute of Interplanetary Space Physics (IFSI CNR) are presented. Sharp, well-defined double layers were observed downstream of a contactor collecting electrons from an ambient plasma created in the IFSI Facility. The voltage drop across these double layers was observed to increase with the current drawn from the ambient plasma. This observation, which was not as clear in previous IFSI tests conducted at higher neutral pressures, is in agreement with previous experimental observations made at both Colorado State University and NASA Lewis Research Center. Greater double layer voltage drops, multiple double layers, and higher noise levels in the region near the double layers were also observed when a magnetic field was imposed and oriented perpendicular to the line joining the contactor and simulator.

Williams, John D.; Wilbur, Paul J.

1991-01-01

140

Plasma Spray System  

NASA Technical Reports Server (NTRS)

Computer aided, fully-automatic TRW system sprays very hot plasma onto a turbine blade. Composed of gas into which metallic and ceramic powders have been injected, the plasma forms a two-layer coating which insulates the blade. Critical part of operation is controlling the thickness of the deposit which is measured in thousandths of an inch. This is accomplished by an optical detector which illuminates spots at various locations on the blade and determines thickness by measuring the light reflections. Optical sensor monitors spraying process until precise thickness is attained, then computer halts the spraying.

1980-01-01

141

Solar flares. [plasma physics  

NASA Technical Reports Server (NTRS)

The present paper deals with explosions in a magnetized solar plasma, known as flares, whose effects are seen throughout the electromagnetic spectrum, from gamma-rays through the visible and to the radio band. The diverse phenomena associated with flares are discussed, along with the physical mechanisms that have been advanced to explain them. The impact of solar flare research on the development of plasma physics and magnetohydrodynamics is noted. The rapid development of solar flare research during the past 20 years, owing to the availability of high-resolution images, detailed magnetic field measurements, and improved spectral data, is illustrated.

Rust, D. M.

1979-01-01

142

Study of plasma chemistry in plasma doping processes  

Microsoft Academic Search

Summary form only given. An empirical-analytic approach has been used for the plasma chemistry analysis of plasma ion implantation (PII) doping experiments. Least square (LS) fittings of SIMS profiles have been performed to find the relationship between gas, plasma, and dose compositions in multi-species plasmas and to optimize gas recipes and process conditions. A dynamic sheath model of the multi-species

Shu Qin; Yuanzhong Zhou; Chung Chan; Jiqun Shao; S. Denholm

1997-01-01

143

Electrical characterization of the plasma jet generated by plasma pencil  

Microsoft Academic Search

Recent studies have shown that low temperature atmospheric pressure plasma jets are formed by the propagation of small plasma bullets traveling at very high velocities in ambient air. In this paper we report on the spatial evolution of the plasma jet properties investigated from the jet current density, where the jet current was measured by placing a lab-made probe along

A. Begum; M. Laroussi

2010-01-01

144

Recent results for plasma antennas  

SciTech Connect

Plasma antennas are just as effective as metal antennas. They can transmit, receive, and reflect radio waves just as well as metal antennas. In addition, plasma generated noise does not appear to be a problem.

Alexeff, Igor; Anderson, Ted; Farshi, Esmaeil; Karnam, Naresh; Pulasani, Nanditha Reddy [Department of Electrical Engineering, University of Tennessee, Knoxville, Tennessee 37996 (United States)

2008-05-15

145

Process Sprays Uniforms Plasma Coatings  

NASA Technical Reports Server (NTRS)

Composite-powder processing procedure developed along with plasma-spray parameters to achieve homogeneous, well-bonded, low-porosity, self-lubricating coatings. Multicomponent plasma coatings are applied without segretation of components.

Sliney, H. E.; Jacobson, T. P.; Walther, G. C.; Nakamura, H. H.

1983-01-01

146

A plasma receiving dipole antenna  

SciTech Connect

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.

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

147

A microwave plasma cleaning apparatus  

NASA Technical Reports Server (NTRS)

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.

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

1995-01-01

148

Time Dependence in Plasma Codes  

E-print Network

Time-dependent plasma codes are a natural extension of static nonequilibrium plasma codes. Comparing relevant timescales will determine whether or not time-dependent treatment is necessary. In this article I outline the ingredients for a time-dependent plasma code in a homogeneous medium and discuss the computational method. In the second half of the article I describe recombination in the early Universe as a detailed example of a problem whose solution requires a time-dependent plasma code.

S. Seager

2001-06-12

149

Magnetoacoustic solitons in quantum plasma  

SciTech Connect

Nonlinear magnetoacoustic waves in collisionless homogenous, magnetized quantum plasma is studied. Two fluid quantum magneto-hydrodynamic model (QMHD) is employed and reductive perturbation method is used to derive Korteweg de Vries (KdV) equation for magnetoacoustic waves. The effects of plasma density and magnetic field intensity are investigated on magnetoacoustic solitary structures in quantum plasma. The numerical results are also presented, which are applicable to explain some aspects of the propagation of nonlinear magnetoacosutic wave in dense astrophysical plasma situations.

Hussain, S.; Mahmood, S. [Theoretical Plasma Physics Division (TPPD), PINSTECH, P.O. Nilore, Islamabad (Pakistan); Department of Physics and Applied Mathematics (DPAM), PIEAS, P.O. Nilore, Islamabad (Pakistan)

2011-08-15

150

PLASMA ANTIOXIDANT MEASUREMENTS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Measures of in vivo antioxidant status are important in understanding the role of oxidative events in the initiation and progression of numerous diseases, including cancer, atherosclerosis, and diabetes. In vivo antioxidant status can be assessed by measuring individual plasma or tissue levels of an...

151

Flare Plasma Iron Abundance  

NASA Technical Reports Server (NTRS)

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.

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

2008-01-01

152

Vacuum plasma spray coating  

NASA Technical Reports Server (NTRS)

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.

Holmes, Richard R.; Mckechnie, Timothy N.

1989-01-01

153

Quark gluon plasma  

Microsoft Academic Search

Recent trends in the research of quark gluon plasma (QGP) are surveyed and the current experimental and theoretical status\\u000a regarding the properties and signals of QGP is reported. We hope that the experiments commencing at relativistic heavy-ion\\u000a collider (RHIC) in 2000 will provide a glimpse of the QGP formation.

C P Singh

2000-01-01

154

Computations in Plasma Physics.  

ERIC Educational Resources Information Center

Discusses contributions of computers to research in magnetic and inertial-confinement fusion, charged-particle-beam propogation, and space sciences. Considers use in design/control of laboratory and spacecraft experiments and in data acquisition; and reviews major plasma computational methods and some of the important physics problems they…

Cohen, Bruce I.; Killeen, John

1983-01-01

155

High-temperature plasma physics  

SciTech Connect

Both magnetic and inertial confinement research are entering the plasma parameter range of fusion reactor interest. This paper reviews the individual and common technical problems of these two approaches to the generation of thermonuclear plasmas, and describes some related applications of high-temperature plasma physics.

Furth, H.P.

1988-03-01

156

Plasma chemistry and its applications  

NASA Technical Reports Server (NTRS)

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).

Hozumi, K.

1980-01-01

157

Controlled zone microwave plasma system  

DOEpatents

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.

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

2009-10-20

158

Numerical simulation of dusty plasmas  

SciTech Connect

The numerical simulation of physical processes in dusty plasmas is reviewed, with emphasis on recent results and unresolved issues. Three areas of research are discussed: grain charging, weak dust-plasma interactions, and strong dust-plasma interactions. For each area, we review the basic concepts that are tested by simulations, present some appropriate examples, and examine numerical issues associated with extending present work.

Winske, D.

1995-09-01

159

Plasma Physics John F. Kennedy  

E-print Network

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

Princeton Plasma Physics Laboratory

160

Radar scattering from dusty plasmas  

Microsoft Academic Search

A calculation of the scattering cross section of charged dust particles in a plasma is carried out for an incident electromagnetic wave with frequency much larger than the electron plasma frequency. The present derivation employs the dressed test particle theorem of Hubbard and Rostoker. A critical discussion on the applicability of conventional plasma theory - as employed here - is

César la Hoz

1992-01-01

161

Plasma medicine: an introductory review  

Microsoft Academic Search

This introductory review on plasma health care is intended to provide the interested reader with a summary of the current status of this emerging field, its scope, and its broad interdisciplinary approach, ranging from plasma physics, chemistry and technology, to microbiology, biochemistry, biophysics, medicine and hygiene. Apart from the basic plasma processes and the restrictions and requirements set by international

M. G. Kong; GMW Kroesen; GE Morfill; T. Nosenko; T. Shimizu; J. van Dijk; J. L. Zimmermann

2009-01-01

162

Plasma Physics for Nuclear Fusion  

Microsoft Academic Search

The book focuses on the properties of gaseous plasmas needed in the attainment of controlled fusion reactions. The first five chapters develop the fundamentals of plasma physics and present the conditions of nuclear fusion reactions. The next four provide a magnetohydrodynamic description of plasmas, followed by four chapters that explain wave phenomena and instabilities by means of a kinetic model.

K. Miyamoto; Robert L. Dewar

1980-01-01

163

High-power radiating plasma  

NASA Technical Reports Server (NTRS)

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.

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

1984-01-01

164

Plasma wave propagation with a plasma density gradient  

NASA Astrophysics Data System (ADS)

Plasma waves with the plasma diffusion velocity un due to a plasma density gradient are described in a positive column plasma. The ion wave is generated by the perturbation of the operating frequency 106 s-1 and it propagates with the group velocity ug˜cs2/un˜(105-106) m/s, where cs is the acoustic velocity in a fine tube fluorescent lamp, while the electron wave cannot be generated with a turbulence of low frequency less than the electron oscillation frequency ?pe. The propagation of the lighting signal observed in long tube fluorescent lamps is well understood with the propagation of ion waves occurring along the plasma density gradient.

Cho, Guangsup; Choi, Eun-Ha; Uhm, Han Sup

2011-03-01

165

Human Plasma Protein C  

PubMed Central

Protein C is a vitamin K-dependent protein, which exists in bovine plasma as a precursor of a serine protease. In this study, protein C was isolated to homogeneity from human plasma by barium citrate adsorption and elution, ammonium sulfate fractionation, DEAE-Sephadex chromatography, dextran sulfate agarose chromatography, and preparative polyacrylamide gel electrophoresis. Human protein C (Mr = 62,000) contains 23% carbohydrate and is composed of a light chain (Mr = 21,000) and a heavy chain (Mr = 41,000) held together by a disulfide bond(s). The light chain has an amino-terminal sequence of Ala-Asn-Ser-Phe-Leu- and the heavy chain has an aminoterminal sequence of Asp-Pro-Glu-Asp-Gln. The residues that are identical to bovine protein C are underlined. Incubation of human protein C with human ?-thrombin at an enzyme to substrate weight ratio of 1:50 resulted in the formation of activated protein C, an enzyme with serine amidase activity. In the activation reaction, the apparent molecular weight of the heavy chain decreased from 41,000 to 40,000 as determined by gel electrophoresis in the presence of sodium dodecyl sulfate. No apparent change in the molecular weight of the light chain was observed in the activation process. The heavy chain of human activated protein C also contains the active-site serine residue as evidenced by its ability to react with radiolabeled diisopropyl fluorophosphate. Human activated protein C markedly prolongs the kaolin-cephalin clotting time of human plasma, but not that of bovine plasma. The amidolytic and anticoagulant activities of human activated protein C were completely obviated by prior incubation of the enzyme with diisopropyl fluorophosphate. These results indicate that human protein C, like its bovine counterpart, exists in plasma as a zymogen and is converted to a serine protease by limited proteolysis with attendant anticoagulant activity. Images PMID:468991

Kisiel, Walter

1979-01-01

166

The Plasma Pencil: A Novel Pulsed Plasma Source*  

NASA Astrophysics Data System (ADS)

One of the attractive characteristics of nonequilibrium plasmas is their enhanced plasma chemistry without the need for elevated gas temperatures. Using nanoseconds high voltage pulses the electron energy distribution function can be controlled in a way to shift it towards the high-energy tail. Higher electrons energies lead to enhanced gas phase chemistry. This is advantageous in material processing applications where advanced chemical processes under low temperature conditions are desirable. In this paper, we report on a novel pulsed cold plasma source, the ``plasma pencil'' [1], and its unique characteristics. The plasma pencil is capable of generating a cold plasma plume several centimeters in length. It exhibits low power requirements and by using helium as a carrier gas the gas temperature remains low for extended periods of operation. The plasma plume emitted by the plasma pencil can be applied to bare skin without causing any heating or painful sensation. In this paper, the characteristics of the plasma pencil will be discussed. These include the current-voltage characteristics, plume temperature, emission spectra, and the time and spatial evolution of the plasma plume. *Work supported by the Air Force Office of Scientific Research (AFOSR). [1] M. Laroussi and X. Lu, ``Room Temperature Atmospheric Pressure Plasma Plume for Biomedical Applications'', Applied Physics Letters, Vol. 87, 2005.

Akan, Tamer; Lu, Xinpei; Laroussi, Mounir

2006-10-01

167

Dense Plasma Injectors for the HyperV Plasma Jets  

NASA Astrophysics Data System (ADS)

HyperV is developing high velocity dense plasma jets for application to fusion and HEDP. The approach uses symmetric pulsed injection of high density plasma into a coaxial EM accelerator having a cross-section tailored to prevent formation of the blow-by instability. Work to date has focused on injection using ablative plasma sources, such as capillaries and sparkgaps, but injection of pure plasma, such as D and T, or high-Z gases such as Argon, require a different approach. We describe experiments and diagnostic measurements to develop small parallel plate railguns (MiniRailguns) to generate high density plasma pulses for injection into the coax gun. We also present a brief update of latest results from the 112 electrode sparkgap gun and the 64 capillary TwoPi plasma jet merging experiment, both of which have been upgraded with higher energy pulse forming networks to double the mass of ablatively injected plasma.

Witherspoon, F. Douglas; Bomgardner, Richard; Case, Andrew; Messer, Sarah; Brockington, Samuel

2008-04-01

168

Plasma dynamics in microsecond megaampere plasma opening switches  

SciTech Connect

The paper considers the transport of a magnetic field in highly ionized plasma of microsecond megaampere plasma opening switches. Self-similar solutions for plasma aggregation by a linearly increasing magnetic field are derived. For these solutions, the magnetic field energy in the current channel is much lower than the energy of the accelerated plasma flow. The effect of Joule heating of the plasma becomes profound only with a uniform current density. It is shown that the evolution of the magnetic field in the accelerated flow is reduced to diffusion with an effective electrical conductivity proportional to the harmonic average of the Spitzer conductivity and conductivity dependent on the magnetic field in the current channel. Thus, during about the first 100 ns of the current pulse the conductivity of the current channel increases due to the plasma heating and, as the plasma is accelerated, its conductivity decreases.

Loginov, S. V. [Institute of High Current Electronics SB RAS, Tomsk 634055 (Russian Federation)

2011-10-15

169

Gravitational lensing in plasma: Relativistic images at homogeneous plasma  

E-print Network

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 ar...

Tsupko, Oleg Yu

2013-01-01

170

Pulsed Electromagnetic Acceleration of Plasmas  

NASA Technical Reports Server (NTRS)

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.

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

2002-01-01

171

Experimental Plasma Research project summaries  

SciTech Connect

This report contains descriptions of the activities supported by the Experimental Plasma Research Branch of APP. The individual project summaries were prepared by the principal investigators and include objectives and milestones for each project. The projects are arranged in six research categories: Plasma Properties; Plasma Heating; Plasma Diagnostics; Atomic, Molecular and Nuclear Physics; Advanced Superconducting Materials; and the Fusion Plasma Research Facility (FPRF). Each category is introduced with a statement of objectives and recent progress and followed by descriptions of individual projects. An overall budget summary is provided at the beginning of the report.

None

1980-09-01

172

Closed inductively coupled plasma cell  

DOEpatents

A closed inductively coupled plasma cell generates a relatively high power, low noise plasma for use in spectroscopic studies. 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.

Manning, Thomas J. (Gainesville, FL); Palmer, Byron A. (Los Alamos, NM); Hof, Douglas E. (Santa Fe, NM)

1990-01-01

173

Plasma Opening Switch Synchronization Facility  

NASA Astrophysics Data System (ADS)

The Baikal program provides a superpower generator creation which uses a plasma opening switch for output pulse production. The MOL facility is being developed within the frames of this program to test main units and systems of the planned generator at 4-6 MV, 3 MA and 100 ns. The MOL facility is planned to use 7 parallel plasma opening switch modules placed in the relatively compact vacuum chamber of 140 cm diameter. This aims at solving two main technical issued: plasma opening switch module development with external applied magnetic field and plasma switch modules synchronization. The paper describes plasma switch module design and low inductance load synchronization experimental tests results.

Altuhov, Aleksey A.; Blinov, Petr I.; Dolgachev, Georgi I.; Maslennikov, Dmitry D.; Khodeev, Ivan A.

2002-12-01

174

Modulational interactions in quantum plasmas  

SciTech Connect

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.

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

175

Transport processes in space plasmas  

SciTech Connect

This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The project represents a comprehensive research effort to study plasma and field transport processes relevant for solar-terrestrial interaction, involving the solar wind and imbedded magnetic field and plasma structures, the bow shock of the Earth`s magnetosphere and associated waves, the Earth`s magnetopause with imbedded flux rope structures and their connection with the Earth, plasma flow in the Earth`s magnetotail, and ionospheric beam/wave interactions. The focus of the work was on the interaction between plasma and magnetic and electric fields in the regions where different plasma populations exist adjacent to or superposed on each other. These are the regions of particularly dynamic plasma behavior, important for plasma and energy transport and rapid energy releases. The research addressed questions about how this interaction takes place, what waves, instabilities, and particle/field interactions are involved, how the penetration of plasma and energy through characteristic boundaries takes place, and how the characteristic properties of the plasmas and fields of the different populations influence each other on different spatial and temporal scales. These topics were investigated through combining efforts in the analysis of plasma and field data obtained through space missions with theory and computer simulations of the plasma behavior.

Birn, J.; Elphic, R.C.; Feldman, W.C. [and others

1997-08-01

176

Plasma opening switch conduction scaling  

NASA Astrophysics Data System (ADS)

Plasma opening switch (POS) experiments performed on the Hawk generator [Commisso et al., Phys. Fluids B 4, 2368 (1992)] (750 kA, 1.2 ?s) determine the dependence of the conduction current and conduction time on plasma density, electrode dimensions, and current rise rate. The experiments indicate that for a range of parameters, conduction is controlled by magnetohydrodynamic (MHD) distortion of the plasma, resulting in a low density region where opening can occur, possibly by erosion. The MHD distortion corresponds to an axial translation of the plasma center-of-mass by half the initial plasma length, leading to a simple scaling relation between the conduction current and time, and the injected plasma density and POS electrode dimensions that is applicable to a large number of POS experiments. For smaller currents and conduction times, the Hawk data suggest a non-MHD conduction limit that may correspond to electromagnetohydrodynamic (EMH) field penetration through the POS plasma.

Weber, B. V.; Commisso, R. J.; Goodrich, P. J.; Grossmann, J. M.; Hinshelwood, D. D.; Ottinger, P. F.; Swanekamp, S. B.

1995-10-01

177

Gravitational lensing in plasma: Relativistic images at homogeneous plasma  

E-print Network

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.

Oleg Yu. Tsupko; Gennady S. Bisnovatyi-Kogan

2013-05-30

178

Gravitational lensing in plasma: Relativistic images at homogeneous plasma  

NASA Astrophysics Data System (ADS)

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 a difference, even in uniform plasma, of the gravitational deflection angle in plasma from the vacuum case. This angle depends on the photon frequency, which 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 formulas are obtained for the case of a very large deflection angle, exceeding 2?. We apply these formulas 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.

Tsupko, Oleg Yu.; Bisnovatyi-Kogan, Gennady S.

2013-06-01

179

[Plasma cell leukemia].  

PubMed

Plasma cell leukemia (PCL) is a rare disorder which develops spontaneously (primary PCL) or evolves in patients with multiple myeloma (secondary PCL). It is defined by the presence of 2 × 10(9)/L peripheral blood plasma cells or plasmacytosis accounting for more than 20 % of the differential white cell count. PCL presents more often extramedullary involvement, anemia, thrombocytopenia, hypercalcemia, as well as impaired renal function. Cytogenetic abnormalities and mutations observed in PCL lead to escape from immune surveillance and independence from the bone marrow microenvironment with changes in expression of adhesion molecules or chemokines receptors. The outcome of PCL has improved with combination approaches with novel agents (including bortezomib and immunomodulatory drugs, such as lenalidomide) and with autologous stem cell transplantation. Allogeneic hematopoietic stem cell transplantation is currently available for young patients. This article is an overview of this rare and severe disease and the different therapeutics options that are recommended. PMID:25418598

Ravinet, Aurélie; Bay, Jacques Olivier; Tournilhac, Olivier

2014-11-01

180

Plasma dust crystallization  

NASA Technical Reports Server (NTRS)

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.

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

1994-01-01

181

Plasma and magnetospheric research  

NASA Technical Reports Server (NTRS)

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.

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

1985-01-01

182

Spectroscopy of divertor plasmas  

SciTech Connect

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.

Isler, R.C.

1995-12-31

183

Electrons, Ions and Plasma  

NSDL National Science Digital Library

This explanation of the factors that produce the polar aurora, (northern lights) discusses the role of electrons in the ionosphere, positive ions in the solar wind, and the mixing of the two to create plasma. The work of Kristian Birkeland of Norway in exploring the cause of the aurora is cited and a link leads to in-depth information on auroras, including some dramatic photographs.

David Stern

184

Dusty spin plasmas  

SciTech Connect

A fluid model is derived, taking into account the effect of spin magnetization of electrons as well as of magnetized dust grains. The model is analyzed, and it is found that both the acoustic velocity and the Alfven velocity is decreased due to the magnetization effects. Furthermore, for low-temperature high density plasmas, it is found that the linear wave modes can be unstable, due to the magnetic attraction of individual fluid elements. The significance of our results are discussed.

Brodin, G.; Marklund, M.; Zamanian, J. [Department of Physics, Umeaa University, SE-901 87 Umeaa (Sweden)

2008-09-07

185

Princeton Plasma Physics Laboratory:  

SciTech Connect

This paper discusses progress on experiments at the Princeton Plasma Physics Laboratory. The projects and areas discussed are: Principal Parameters Achieved in Experimental Devices, Tokamak Fusion Test Reactor, Princeton Large Torus, Princeton Beta Experiment, S-1 Spheromak, Current-Drive Experiment, X-ray Laser Studies, Theoretical Division, Tokamak Modeling, Spacecraft Glow Experiment, Compact Ignition Tokamak, Engineering Department, Project Planning and Safety Office, Quality Assurance and Reliability, and Administrative Operations.

Phillips, C.A. (ed.)

1986-01-01

186

Screening Resonances In Plasmas  

SciTech Connect

When it was suggested that a new recombination mechanism (Resonant Radiative Recombination (RRR)) which, based on very general physical arguments, should happen in dense plasmas and promises to provide useful information for the local temperature and density diagnostics of plasmas, they assumed the existence of screening resonances. For model potentials the existence of screening resonances has been demonstrated beyond reasonable doubt in a number of calculations. The key question, how well those potentials describe the dominant effects of a real plasma remains open. The relation of theoretical predictions to experimentally measurable effects is an important issue at the present stage of their research. In particular, RRR is expected to account for enhanced recombination rates of low energetic electrons with their ions, since the first stage is the resonant capture of a slow electron by an atom or ion. The mechanism that traps an electron is a combination of complicated many-body interactions of the ions and electrons. For clarity they start here, however, with a discussion in terms of local potential traps the shapes of which are determined predominantly and in an average way by two factors: the degree of screening present at the ionic site and the degree of short-range order in the immediate neighborhood of this ion.

Winkler, P.

1998-12-01

187

PLASMA CELL LEUKEMIA  

PubMed Central

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

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

188

Plasma Sensor Suite  

NASA Astrophysics Data System (ADS)

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.

Matlis, Eric; Bowles, Patrick; Corke, Thomas

2008-11-01

189

Influence of Plasma Instabilities in Ceramic Suspension Plasma Spraying  

NASA Astrophysics Data System (ADS)

Direct current Suspension Plasma Spraying (SPS) allows depositing finely structured coatings. This article presents an analysis of the influence of plasma instabilities on the yttria-stabilized suspension drops fragmentation. A particular attention is paid to the treatment of suspension jet or drops according to the importance of voltage fluctuations (linked to those of the arc root) and depending on the different spray parameters such as the plasma forming gas mixture composition and mass flow rate and the suspension momentum. By observing the suspension drops injection with a fast shutter camera and a laser flash sheet triggered by a defined transient voltage level of the plasma torch, the influence of plasma fluctuations on jet or drops fragmentation is studied through the deviation and dispersion trajectories of droplets within the plasma jet.

Etchart-Salas, R.; Rat, V.; Coudert, J. F.; Fauchais, P.; Caron, N.; Wittman, K.; Alexandre, S.

2007-12-01

190

Lithium plasma emitter for collisionless magnetized plasma experiment  

SciTech Connect

This paper presents a newly developed lithium plasma emitter, which can provide quiescent and low-temperature collisionless conditions for magnetized plasma experiments. This plasma emitter generates thermal emissions of lithium ions and electrons to produce a lithium plasma. Lithium type beta-eucryptite and lanthanum-hexaboride (LaB{sub 6}) powders were mixed and directly heated with a tungsten heater to synthesize ion and electron emissions. As a result, a plasma with a diameter of {approx}15 cm was obtained in a magnetic mirror configuration. The typical range of electron density was 10{sup 12}-10{sup 13} m{sup -3} and that of electron temperature was 0.1-0.8 eV with the emitter operation temperature of about 1500 K. The amplitude fluctuations for the plasma density were lower than 1%.

Kawamori, Eiichirou; Huang, Yi-Jue; Song, Sung-Xuang; Hsieh, Tung-Yuan [Institute of Space, Astrophysical and Plasma Sciences, National Cheng Kung University, Tainan, Taiwan (China); Lee, Jyun-Yi; Syugu, Wun-Jheng [Department of Physics, National Cheng Kung University, Tainan, Taiwan (China); Cheng, C. Z. [Plasma and Space Science Center, National Cheng Kung University, Tainan, Taiwan (China)

2011-09-15

191

Plasma generating apparatus for large area plasma processing  

DOEpatents

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.

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

1991-01-01

192

Systematic study of plasma flow during plasma sheet thinnings  

NASA Technical Reports Server (NTRS)

On the basis of a study of Imp 6 measurements of plasma flow, it is concluded that there is no clear indication of a predominance of tailward plasma flow beyond about X = -15 R sub E in the midnight sector of the plasma sheet during the expansive phase of a substorm. In fact, it is shown statistically that sunward plasma flow is more frequently observed in the midnight sector within about 30 R sub E from the earth than in any other direction during plasma sheet thinning at the substorm expansion. This result supports the conclusion that there is no definite evidence for the formation of a reconnection neutral line in the near-earth plasma sheet during most substorms.

Lui, A. T. Y.; Frank, L. A.; Ackerson, K. L.; Meng, C.-I.; Akasofu, S.-I.

1977-01-01

193

Plasma viscosity: a forgotten variable.  

PubMed

Evaluation of plasma viscosity has been underutilized in the clinical practice. Plasma viscosity is determined by water-content and macromolecular components. Plasma is a highly concentrated protein solution, therefore weak protein-protein interactions can play a role that is not characterized by electrophoresis. The effect of a protein on plasma viscosity depends on its molecular weight and structure. The less spheroid shape, the higher molecular weight, the higher aggregating capacity, and the higher temperature or pH sensitivity a protein has, the higher plasma viscosity results. Plasma is a Newtonian fluid, its viscosity does not depend on flow characteristics, therefore it is simple to measure, especially in capillary viscosimeters. Its normal value is 1.10-1.30 mPa s at 37 degrees C and independent of age and gender. The measurement has high stability and accuracy, thus little alterations may be pathologically important. Inflammations, tissue injuries resulting in plasma protein changes can increase its value with high sensitivity, though low specificity. It can increase in parallel with erythrocyte sedimentation rate (ESR), but it is not influenced by hematocrit (anemia, polycytemia), or time to analysis. Based on these favorable features, in 1942 plasma viscosity was recommended to substitute ESR. In hyperviscosity syndromes plasma viscosity is better in follow-up than ESR. In rheumatoid arthritis, its sensitivity and specificity are better than that of ESR or C-reactive protein. Plasma fibrinogen concentration and plasma viscosity are elevated in unstable angina pectoris and stroke and their higher values are associated with higher rate of major adverse clinical events. Elevation of plasma viscosity correlates to the progression of coronary and peripheral artery diseases. In conclusion, plasma viscosity should be measured routinely in medical practice. PMID:18503132

Késmárky, Gábor; Kenyeres, Péter; Rábai, Miklós; Tóth, Kálmán

2008-01-01

194

Plasma Sterilization Technology for Spacecraft Applications  

NASA Technical Reports Server (NTRS)

The application of plasma gas technology to sterilization and decontamination of spacecraft components is considered. Areas investigated include: effective sterilizing ranges of four separate gases; lethal constituents of a plasma environment; effectiveness of plasma against a diverse group of microorganisms; penetrating efficiency of plasmas for sterilization; and compatibility of spacecraft materials with plasma environments. Results demonstrated that plasma gas, specifically helium plasma, is a highly effective sterilant and is compatible with spacecraft materials.

Fraser, S. J.; Olson, R. L.; Leavens, W. M.

1975-01-01

195

A contoured gap coaxial plasma gun with injected plasma armature  

NASA Astrophysics Data System (ADS)

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.

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

2009-08-01

196

A contoured gap coaxial plasma gun with injected plasma armature.  

PubMed

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

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

2009-08-01

197

Average plasma properties in the central plasma sheet  

SciTech Connect

Using four months of tail data obtained by the three-dimensional plasma instrument on board the AMPTE/IRM satellite in 1986, the authors have done a statistical survey on the behavior of ion and electron moments in the central plasma sheet. Almost 80,000 spin averages of plasma density, ion bulk velocity, ion and electron temperature, and plasma {beta} were analyzed with respect to differences between their values in the inner and outer central plasma sheet as well as their dependence on magnetic activity. The ion temperature increases with increasing magnetic activity while the ion density decreases during disturbed intervals, except in the neutral sheet neighborhood at smaller radial distances. The ion and electron temperatures in the central plasma sheet are highly correlated, with T{sub i}/T{sub e} being constant over a wide range of temperatures and about twice as large as in the distant tail. The average ion flow speeds in the central plasma sheet are below 100 km/s and nearly identical to those found in the plasma sheet boundary layer, although the distribution functions usually are quite different. High-speed flows do occur, but in bursts of most often less than 1 min duration with intermittent intervals of nearly stagnant plasma. The distribution of flow directions strongly favors sunward flow for velocities above 300 km/s, indicating that a near-earth neutral line is rarely, if ever, located inside of X{sub GSM} = {minus} 19 R{sub E}.

Baumjohann, W.; Paschmann, G. (Max-Planck-Institut fuer Physik und Astrophysik, Garching (West Germany)); Cattell, C.A. (Univ. of California, Berkeley (USA))

1989-06-01

198

Plasma cavitation in ultraintense laser interactions with underdense helium plasmas  

NASA Astrophysics Data System (ADS)

Plasma cavitation in an underdense helium plasma driven by an ultraintense laser pulse (I>1020 W cm-2) is studied. Shadowgraphy and interferometry diagnose plasma channel formation as the laser pulse propagates through the underdense plasma. Measurements of the spatially resolved Thomson side-scattered light generated by the intense-driver pulse indicate the transverse and longitudinal extremities of the cavitated regions that form. Multiple laser-driven channels are observed and each is shown to be a source of electrons with energies greater than 100 MeV. Electron cavitation within an ion channel is consistent with the direct laser acceleration (DLA) mechanism that is present.

Nilson, P. M.; Mangles, S. P. D.; Willingale, L.; Kaluza, M. C.; Thomas, A. G. R.; Tatarakis, M.; Clarke, R. J.; Lancaster, K. L.; Karsch, S.; Schreiber, J.; Najmudin, Z.; Dangor, A. E.; Krushelnick, K.

2010-04-01

199

A contoured gap coaxial plasma gun with injected plasma armature  

SciTech Connect

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.

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

200

Plasma surface cleaning in a microwave plasma source  

SciTech Connect

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 {mu}m in thickness) of Shell Vitrea oil and cleaned by using such reactive plasmas. The plasma cleaning was done in discharge conditions of microwave power up to 1300 W, radio frequency power up to 200 W, biased potential up to 400 V, gas pressures up to 5 mtorr, and operating time up to 35 min. The surface texture of the postcleaned samples has been examined visually. Mass loss of the samples after plasma cleaning was measured to estimate cleaning rates. Measured clean rates of low-pressure (0.5-mtorr) argon/oxygen plasmas were as high as 2.7 {mu}m/min. X-ray photoelectron spectroscopy (XPS) was used to determine cleanliness of the sample surfaces after plasma cleaning. The XPS study on polished samples confirmed the effectiveness of plasma cleaning in achieving atomic level of surface cleanliness. In this technical memorandum plasma properties, cleaning phenomena, and significant results are reported and discussed.

Tsai, C.C.; Nelson, W.D.; Haselton, H.H.; Schechter, D.E. [Oak Ridge National Lab., TN (United States); Thompson, L.M.; Campbell, V.B.; Glover, A.L.; Googin, J.M. [Oak Ridge Y-12 Plant, TN (United States)

1994-03-01

201

Plasma flows in MPD thrusters  

NASA Astrophysics Data System (ADS)

A fundamental description of the plasma acceleration process in magnetoplasmadynamic (MPD) thrusters is presented. The properties of plasma flows in self-field MPD thrusters are investigated by adopting a stationary, axisymmetric, resistive magnetohydrodynamic plasma model. First, the acceleration process in a cylindrical MPD channel is analyzed by neglecting the gasdynamic pressure term. A class of solutions is presented, which allows for a simple analytical treatment of the flow. The physical and mathematical nature of the flow is thus described in terms of two characteristic parameters: a dimensionless channel length, scaled with the plasma resistive length, and a dimensionless parameter which depends on the applied voltage. Then, the effect of gasdynamic pressure is investigated. The presented approach gives an effective description of the plasma acceleration process and defines a framework for the parametric analysis of plasma flows in MPD thrusters.

Giannelli, Sebastiano; Andreussi, Tommaso; Pegoraro, Francesco; Andrenucci, Mariano

2011-11-01

202

Electron cyclotron resonance plasma photos  

SciTech Connect

In order to observe and study systematically the plasma of electron cyclotron resonance (ECR) ion sources (ECRIS) we made a high number of high-resolution visible light plasma photos and movies in the ATOMKI ECRIS Laboratory. This required building the ECR ion source into an open ECR plasma device, temporarily. An 8MP digital camera was used to record photos of plasmas made from Ne, Ar, and Kr gases and from their mixtures. We studied and recorded the effect of ion source setting parameters (gas pressure, gas composition, magnetic field, and microwave power) to the shape, color, and structure of the plasma. The analysis of the photo series gave us many qualitative and numerous valuable physical information on the nature of ECR plasmas.

Racz, R.; Palinkas, J. [Institute of Nuclear Research (ATOMKI), H-4026 Debrecen, Bem ter 18/c (Hungary); University of Debrecen, H-4010 Debrecen, Egyetem ter 1 (Hungary); Biri, S. [Institute of Nuclear Research (ATOMKI), H-4026 Debrecen, Bem ter 18/c (Hungary)

2010-02-15

203

Plasma ignition for laser propulsion  

NASA Technical Reports Server (NTRS)

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.

Askew, R. F.

1982-01-01

204

Slotted antenna waveguide plasma source  

NASA Technical Reports Server (NTRS)

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.

Foster, John (Inventor)

2007-01-01

205

Resonance microwave volume plasma source  

SciTech Connect

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.

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

206

Plasma postheparin diamine oxidase activity  

Microsoft Academic Search

Plasma diamine oxidase (DAO) activity may reflect intestinal involvement in Crohn's disease. The purpose of this study was\\u000a to develop a simple heparin stimulation test for assessing postheparin plasma diamine oxidase activity in Crohn's disease.\\u000a Ten volunteers and five patients with Crohn's disease received 1000 units and 3000 units of heparin intravenously and plasma\\u000a samples were obtained at timed intervals.

Jon S. Thompson; David A. Burnett; Robert A. Cormier; William P. Vaughan

1988-01-01

207

Plasma Processes for Semiconductor Fabrication  

Microsoft Academic Search

Plasma processing is a central technique in the fabrication of semiconductor devices. This self-contained book provides an up-to-date description of plasma etching and deposition in semiconductor fabrication. It presents the basic physics and chemistry of these processes, and shows how they can be accurately modeled. The author begins with an overview of plasma reactors and discusses the various models for

W. N. G. Hitchon

1999-01-01

208

Plasma Processing Modeling and Databases  

Microsoft Academic Search

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

W. L. Morgan

1998-01-01

209

Strongly magnetized classical plasma models  

NASA Technical Reports Server (NTRS)

Discrete particle processes in the presence of a strong external magnetic field were investigated. These processes include equations of state and other equilibrium thermodynamic relations, thermal relaxation phenomena, transport properties, and microscopic statistical fluctuations in such quantities as the electric field and the charge density. Results from the equilibrium statistical mechanics of two-dimensional plasmas are discussed, along with nonequilibrium statistical mechanics of the electrostatic guiding-center plasma (a two-dimensional plasma model).

Montgomery, D.; Peyraud, J.; Dewitt, C.

1974-01-01

210

Plasma characterization of dry ?-EDM  

Microsoft Academic Search

An attempt was made to characterize the dry microelectric discharge machining (?-EDM) plasma systematically by using optical\\u000a emission spectroscopy. In order to characterize the plasma and its parameters such as plasma temperature, electron density,\\u000a Debye length, and gamma parameter, the optical spectra were recorded for different energies and with different diameters of\\u000a tool electrode. From the recorded spectra, using line

S. Kanmani Subbu; G. Karthikeyan; J. Ramkumar; S. Dhamodaran

2011-01-01

211

The plasma environment of comets  

SciTech Connect

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.

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

1991-01-01

212

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

SciTech Connect

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)

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

213

Vacuum Plasma Spraying Replaces Electrodeposition  

NASA Technical Reports Server (NTRS)

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.

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

1992-01-01

214

Electrical characterization of rf plasmas  

SciTech Connect

Radio-frequency (rf) electrical sources are commonly used to generate plasmas for processing of industrial materials and for related experimental work. Published descriptions of such plasmas usually include generator-power measurements, and occasionally include plasma dc-bias measurements. One or both of these quantitites are also used in industrial feedback ccontrol systems for setpoint regulation. Recent work at Sandia an elsewhere with an experimental rf discharge device (the GEC RF Reference Cell'') has shown that power and dc-bias levels are often insufficient information for specifying the state of the plasma. The plasma can have nonlinear electrical characteristics that cause harmonic generation, and the harmonic levels can depend sensitively on the impedance of the external circuitry at harmonic frequencies. Even though the harmonics may be low in amplitude, they can be directly related to large changes in plasma power and to changes in optical emission from the plasma. Consequently, in order for a worker to truly master the plasma-generation process, it is necessary to understand, measure, and control electrical characteristics of the plamsa. In this paper we describe technique that have been developed from work with the Reference Cell for making electrical measurements on rf plasmas, and we describe surprising observations of harmonic behavior. 10 refs., 4 figs.

Miller, P.A.

1991-08-01

215

Radioimmunoassay of atropine in plasma.  

PubMed

Antibodies, against atropine, were produced in rabbits immunized with atropine conjugated to bovine serum albumin. The antisera possessed a high binding affinity and were quite specific. The sensitivity of the method allowed detection of 6.25 ng of atropine per ml of plasma in a 10-microliter specimen. The method does not require an extraction procedure and can be performed using very small volumes of plasma. Plasma concentration-time profiles were determined by this method in dogs after rapid i.v. administration of atropine. Atropine declined from plasma in a biexponential fashion, exhibiting a terminal half-life of approximately 2.1 hours. PMID:909073

Wurzburger, R J; Miller, R L; Boxenbaum, H G; Spector, S

1977-11-01

216

First Observation of Electrorheological Plasmas  

SciTech Connect

We report the experimental discovery of ''electrorheological (ER) complex plasmas,'' where the control of the interparticle interaction by an externally applied electric field is due to distortion of the Debye spheres that surround microparticles (dust) in a plasma. We show that interactions in ER plasmas under weak ac fields are mathematically equivalent to those in conventional ER fluids. Microgravity experiments, as well as molecular dynamics simulations, show a phase transition from an isotropic to an anisotropic (string) plasma state as the electric field is increased.

Ivlev, A. V.; Morfill, G. E.; Thomas, H. M.; Raeth, C.; Huber, P.; Kompaneets, R. [Max-Planck-Institut fuer extraterrestrische Physik, 85741 Garching (Germany); Joyce, G. [University of Maryland, College Park, Maryland 20742 (United States); Fortov, V. E.; Lipaev, A. M.; Molotkov, V. I. [Institute for High Energy Densities, Russian Academy of Sciences, 125412 Moscow (Russian Federation); Reiter, T. [European Astronaut Centre, 51147 Cologne (Germany); Turin, M.; Vinogradov, P. [RSC Energia, 141070 Korolev (Russian Federation)

2008-03-07

217

Spatially extended atmospheric plasma arrays  

Microsoft Academic Search

This paper reports a systematic study of spatially extended atmospheric\\u000a plasma (SEAP) arrays employing many parallel plasma jets packed densely\\u000a and arranged in an honeycomb configuration. The work is motivated by the\\u000a challenge of using inherently small atmospheric plasmas to address many\\u000a large-scale processing applications including plasma medicine. The first\\u000a part of the study considers a capillary-ring electrode configuration as

Z. Cao; Q. Nie; D. L. Bayliss; J. L. Walsh; C. S. Ren; D. Z. Wang; M. G. Kong

2010-01-01

218

Particle simulations in magnetospheric plasmas  

NASA Technical Reports Server (NTRS)

In view of the recent remarkable advancement of computer technology and simulation software, simulation studies are one of the most powerful academic tools for establishment of quantitative space physics and modelling of our space environment. The complex nature encountered in space plasma physics has motivated considerable development in computer simulations, which have played an essential role in the development of space plasma theory. This report describes research undertaken to understand physical processes involved in plasma waves observed in the magnetospheric plasmas, and associated nonlinear phenomena such as heating, diffusion, and acceleration of particles due to excited waves. The research explains and clarifies the observational data both qualitatively and quantitatively.

Nishikawa, Ken-Ichi

1990-01-01

219

How spherical plasma crystals form.  

PubMed

The correlation buildup and the formation dynamics of the shell structure in a spherically confined one-component plasma are studied. Using Langevin dynamics simulations the relaxation processes and characteristic time scales and their dependence on the pair interaction and dissipation in the plasma are investigated. While in systems with Coulomb interaction (e.g., trapped ions) in a harmonic confinement shell formation starts at the plasma edge and proceeds inward, this trend is significantly weakened for dusty plasmas with Yukawa interaction. With a suitable change of the confinement conditions the crystallization scenario can be externally controlled. PMID:20366366

Kählert, H; Bonitz, M

2010-01-01

220

Method for generating surface plasma  

DOEpatents

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.

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

2003-05-27

221

Plasma erosion opening switch  

NASA Astrophysics Data System (ADS)

The plasma erosion opening switch (PEOS) can conduct high current (approx. MA), open quickly ( 10 ns), and withstand high voltage (approx. MV). This switching technique has been used in inductive energy storage experiments and can be used with existing generators for pulse compression, voltage multiplication and power multiplication. The PEOS is used routinely for other types of power conditioning including prepulse suppression, pulse sharpening and multimodule jitter reduction. The PEOS work to data is reviewed. It reviews basic physics principles of the PEOS and outlines the operational limits of a system that employs a PEOS. Examples of present applications of the PEOS are also discussed.

Commisso, R. J.; Cooperstein, G.; Meger, R. A.; Neri, J. M.; Ottinger, P. F.; Weber, B. V.

1985-05-01

222

Plasma wake field accelerator  

SciTech Connect

A new scheme of electron acceleration, employing relativistic electron bunches in a cold plasma, is analyzed. The wake field of a leading bunch is derived in a single-particle model. We then extend the model to include finite bunch length effect. In particular, we discuss the relation between the charge distributions of the driving bunch and the energies transformable to the trailing electrons. It is shown that for symmetric charge distribution of the driving bunches, the maximum energy gain for a driven electron is 2..gamma../sub 0/mc/sup 2/. This limitation can be overcome by introducing asymmetric charge distributions. 13 refs., 5 figs.

Chen, P.; Dawson, J.M.

1985-03-01

223

Renormalization and plasma physics  

SciTech Connect

A review is given of modern theories of statistical dynamics as applied to problems in plasma physics. The derivation of consistent renormalized kinetic equations is discussed, first heuristically, later in terms of powerful functional techniques. The equations are illustrated with models of various degrees of idealization, including the exactly soluble stochastic oscillator, a prototype for several important applications. The direct-interaction approximation is described in detail. Applications discussed include test particle diffusion and the justification of quasilinear theory, convective cells, E vector x B vector turbulence, the renormalized dielectric function, phase space granulation, and stochastic magnetic fields.

Krommes, J.A.

1980-02-01

224

Laser plasma accelerators  

SciTech Connect

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.

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

2012-05-15

225

Fluorescence in Astrophysical Plasmas  

NASA Astrophysics Data System (ADS)

Following the initial detection by Bowen in 1934 of the strong O III lines being due to accidental resonance with strong He II radiation, many strong spectral emission lines are explained as produced by fluorescence. Many of these are Fe II lines pumped by H Ly?, as a consequence of strong radiation from hydrogen and a favorable energy level structure for Fe II. The lines are observed in many types of objects with low density plasma components. The Weigelt condensations in the vicinity of the massive star Eta Carinae is one location where these lines are observed and can be studied in detail, as well as been used for diagnostics.

Hartman, Henrik

226

Plasma Structure and Dynamics  

NASA Astrophysics Data System (ADS)

Despite over a century of observations, the physical processes by which prominence plasma forms and evolves remain controversial. In this chapter we review the observational constraints on all mass formation models, review the four leading models—injection, levitation, evaporation-condensation, and magneto-thermal convection, describe the strengths and weaknesses of each model, and point out opportunities for future work. As needed, short tutorials are provided on fundamental physical mechanisms and concepts not covered in other chapters, including magnetic reconnection and energy balance in coronal loops.

Karpen, Judith T.

227

Cassini Plasma Spectrometer Investigation  

NASA Astrophysics Data System (ADS)

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 Saturn’s magnetosphere and its complex interactions with Titan, the icy satellites and rings, Saturn’s ionosphere and aurora, and the solar wind. Our design approach meets these goals by emphasizing two complementary types of measurements: high-time resolution velocity distributions of electrons and all major ion species; and lower-time resolution, high-mass resolution spectra of all ion species. The CAPS instrument is made up of three sensors: the Electron Spectrometer (ELS), the Ion Beam Spectrometer (IBS), and the Ion Mass Spectrometer (IMS). The ELS measures the velocity distribution of electrons from 0.6 eV to 28,250 keV, a range that permits coverage of thermal electrons found at Titan and near the ring plane as well as more energetic trapped electrons and auroral particles. The IBS measures ion velocity distributions with very high angular and energy resolution from 1 eV to 49,800 keV. It is specially designed to measure sharply defined ion beams expected in the solar wind at 9.5 AU, highly directional rammed ion fluxes encountered in Titan’s ionosphere, and anticipated field-aligned auroral fluxes. The IMS is designed to measure the composition of hot, diffuse magnetospheric plasmas and low-concentration ion species 1 eV to 50,280 eV with an atomic resolution M/?M ˜70 and, for certain molecules, (such asN 2 + and CO+), effective resolution as high as ˜2500. The three sensors are mounted on a motor-driven actuator that rotates the entire instrument over approximately one-half of the sky every 3 min.

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

2004-09-01

228

Pulsed Plasma Thruster Technology  

NASA Technical Reports Server (NTRS)

The continuing emphasis on reducing costs and downsizing spacecraft is forcing increased emphasis on reducing the subsystem mass and integration costs. For many commercial, scientific, and Department of Defense space missions, onboard propulsion is either the predominant spacecraft mass or it limits the spacecraft lifetime. Electromagnetic-pulsed-plasma thrusters (PPT's) offer the combined benefits of extremely low average electric power requirements (1 to 150 W), high specific impulse (approx. 1000 sec), and system simplicity derived from the use of an inert solid propellant. Potential applications range from orbit insertion and maintenance of small satellites to attitude control for large geostationary communications satellites.

1996-01-01

229

Auroral plasma waves  

NASA Technical Reports Server (NTRS)

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.

Gurnett, Donald A.

1989-01-01

230

Modeling of Photoionized Plasmas  

NASA Technical Reports Server (NTRS)

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.

Kallman, Timothy R.

2010-01-01

231

Purification of tantalum by plasma arc melting  

DOEpatents

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.

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

1999-01-01

232

Tool kit for space plasma physics  

E-print Network

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

Demoulin, Pascal

233

An acceleration mechanism for cometary plasma tails  

Microsoft Academic Search

Cometary plasma tail formation by the interaction between the solar wind plasma flow and the plasma at the head of the coma is discussed using the unipolar electric generation theory. The plasma in the 'plasma tail' is almost directly accelerated from the cometary ionopause along the sun-nucleus line where the tail current flows. For steady state solar wind conditions, the

Shigeyuki Minami; R. S. White

1986-01-01

234

Thermal plasma processing in the nineties  

Microsoft Academic Search

In the context of materials which are expected to be one of the major technical issues in the nineties, an attempt is made to describe the role which thermal plasma processing may play in these years. Newer developments in plasma melting\\/remelting, extractive metallurgy, plasma deposition, plasma synthesis, and plasma densification are briefly described since it is anticipated that these developments

E. Pfender

1988-01-01

235

Cold plasma processing technology makes advances  

Technology Transfer Automated Retrieval System (TEKTRAN)

Cold plasma (AKA nonthermal plasma, cool plasma, gas plasma, etc.) is a rapidly maturing antimicrobial process being developed for applications in the food industry. A wide array of devices can be used to create cold plasma, but the defining characteristic is that they operate at or near room temper...

236

23rd National Symposium on Plasma Science & Technology (PLASMA2008)  

Microsoft Academic Search

The Twentieth Century has been a defining period for Plasma Science and Technology. The state of ionized matter, so named by Irving Langmuir in the early part of twentieth century, has now evolved in to a multidisciplinary area with scientists and engineers from various specializations working together to exploit the unique properties of the plasma medium. There have been great

A K Das

2010-01-01

237

Dusty Plasmas: Physics, Chemistry and Technological Impacts in Plasma Processing  

Microsoft Academic Search

A book on the physics and chemistry of dusty plasmas is very welcome. This book, which is much more than collected works in workshop or conference proceedings, proposes a synthesis of current knowledge published in the different fields of dusty plasmas. It is divided into four chapters of nearly equal length, each of them dealing with an important aspect of

J Pelletier

2000-01-01

238

Fission-induced plasmas  

NASA Technical Reports Server (NTRS)

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.

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

1979-01-01

239

Periodically oscillating plasma sphere  

SciTech Connect

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.

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

240

Pulsed Plasma Thruster Contamination  

NASA Technical Reports Server (NTRS)

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.

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

1996-01-01

241

Plasma motor generator system  

NASA Technical Reports Server (NTRS)

The significant potential advantages of a plasma motor generator system over conventional systems for the generation of electrical power and propulsion for spacecraft in low Earth orbits warrants its further investigation. The two main components of such a system are a long insulated wire and the plasma generating hollow cathodes needed to maintain electrical contact with the ionosphere. Results of preliminary theoretical and experimental investigations of this system are presented. The theoretical work involved the equilibrium configurations of the wire and the nature of small oscillation about these equilibrium positions. A particularly interesting result was that two different configurations are allowed when the current is above a critical value. Experimental investigations were made of the optimal starting and running conditions for the proposed, low current hollow cathodes. Although optimal ranges of temperature, argon pressure and discharge voltage were identified, start up became progressively more difficult. This supposed depletion or contamination of the emissive surface could be countered by the addition of new emissive material.

Hite, Gerald E.

1987-01-01

242

Proton radiography in plasma  

NASA Astrophysics Data System (ADS)

Generation of high intensity and well collimated multi-energetic proton beams from laser-matter interaction extends the possibility to use protons as a diagnostic tool to image imploding target in Inertial Confinement Fusion (ICF) experiments. Due to the very large mass densities reached during implosion, protons traveling through the target undergo a very large number of collisions. Therefore the analysis of experimentally obtained proton images requires care and accurate numerical simulations using both hydrodynamic and Monte Carlo codes. The impact of multiple scattering needs to be carefully considered by taking into account the exact stopping power for dense matter and for the underdense plasma corona. In our paper, density, temperature and ionization degree profiles of the imploding target are obtained by 2D hydrodynamic simulations performed using CHIC code. Proton radiography images are simulated using the Monte Carlo code (MCNPX; adapted to correctly describe multiple scattering and plasma stopping power) in order to reconstruct the complete hydrodynamic history of the imploding target. Finally we develop a simple analytical model to study the performance of proton radiography as a function of initial experimental parameters, and identify two different regimes for proton radiography in ICF.

Volpe, L.; Batani, D.; Morace, A.; Nicolai, Ph.; Regan, C.; Ravasio, A.

2011-10-01

243

Analysis of First Plasma in Madison Plasma Dynamo Experiment  

NASA Astrophysics Data System (ADS)

The Madison Plasma Dynamo Experiment (MPDX) is designed to investigate the self-generation of magnetic fields in large astrophysical dynamos. Simulations show that an adequately large Magnetic Reynolds number is needed to produce a dynamo; therefore a large, hot, flowing and unmagnetized plasma is necessary. This poster presents an analysis of the first plasma in MPDX using electrodes that both heat and stir the plasma. A lanthanum hexaboride (LaB6) electron source is used within the 3000 Gauss multipole cusp magnetic field and ExB stirring electrodes govern the plasma flow. This poster analyzes the performance of the efficient and fast power supply used in conjunction with the stirring electrodes to create a controllable flow using a feedback loop. In addition, the effectiveness of the LaB6 electron source will be reported. Supported by the DOE and NSF.

Marchbanks, Christopher; Weisberg, David; Wallace, John; Cooper, Christopher; Forest, Cary

2012-10-01

244

Ion plasma wave and its instability in interpenetrating plasmas  

SciTech Connect

Some essential features of the ion plasma wave in both kinetic and fluid descriptions are presented. The wave develops at wavelengths shorter than the electron Debye radius. Thermal motion of electrons at this scale is such that they overshoot the electrostatic potential perturbation caused by ion bunching, which consequently propagates as an unshielded wave, completely unaffected by electron dynamics. So in the simplest fluid description, the electrons can be taken as a fixed background. However, in the presence of magnetic field and for the electron gyro-radius shorter than the Debye radius, electrons can participate in the wave and can increase its damping rate. This is determined by the ratio of the electron gyro-radius and the Debye radius. In interpenetrating plasmas (when one plasma drifts through another), the ion plasma wave can easily become growing and this growth rate is quantitatively presented for the case of an argon plasma.

Vranjes, J., E-mail: jvranjes@yahoo.com [Institute of Physics Belgrade, Pregrevica 118, 11080 Zemun (Serbia); Kono, M., E-mail: kono@fps.chuo-u.ac.jp [Faculty of Policy Studies, Chuo University, Tokyo (Japan)

2014-04-15

245

Ablation plasma ion implantation  

NASA Astrophysics Data System (ADS)

The novel hybrid technique, Ablation Plasma Ion Implantation (APII), has been characterized and optimized for ion implantation and/or thin film deposition. In APII, a solid target is ablated by a laser; the resulting plasma plume is the source of ions, which are accelerated to high energy by a negative bias voltage imposed on the substrate. The ions are implanted into the substrate, and the neutral atoms in the ablation plume deposit on the substrate in the form of a thin film. Two configurations of APII are characterized and compared. The parallel target-substrate configuration yields ion-beam-assisted deposition and/or ion implantation, and the perpendicular target-substrate configuration yields pure ion implantation mode. A novel theory of the ion matrix sheath has been developed for APII. The ion current predicted by the Child-Langmuir sheath theory matches well with the experimental ion current. Two different target-substrate orientations have been compared for APII. Parallel target-substrate orientation yields ion-beam-assisted-deposition and ion implantation; to prevent arcing, a laser-voltage delay of several microseconds is required for this mode. For the optimized perpendicular target-substrate orientation, the laser can be fired during the voltage pulse, thereby accelerating ions to full energy. Furthermore, the ion dose is higher than that of the parallel target-substrate orientation by a factor of two. The parameters of plasma plumes have been thoroughly characterized by numerous diagnostics, which include electrical characteristics, optical emission spectroscopy, dye laser resonance absorption photography, resonant/non-resonant interferometry, and Langmuir probe. The total number of ions measured by Langmuir probe, and resonant interferometry, is in the range of 1014 ions per laser pulse. Ion dose measured by plasma diagnostics, has been correlated to the ion dose obtained from material analysis, including sputtering yield calculation, X-ray Energy Dispersive Spectroscopy and X-ray Photoelectron Spectroscopy. The retained and delivered ion doses are in the range of 10 12/cm2 per pulse, which is favorable compared to the ion dose obtained from conventional Plasma Immersion Ion Implantation (PHI). The APII ion implantation efficiency is estimated to be about 2%. Ion acceleration and implantation was demonstrated for both of the APB configurations. The feasibility of APII was verified by Cross-Sectional Transmission Electron Microscopy and X-ray Photoelectron Spectroscopy. For parallel target-substrate configuration, the average deposition rate is 0.0075 nm/shot for the Ti -10 kV APII film. Atomic Force Microscopy implemented at Timken Research Lab indicates that the -4 kV APII film has the smoothest surface. Scratch tests performed at Timken Research lab also prove that APR produces excellent film adhesion.

Qi, Bo

246

Arc Plasma Gun With Coaxial Powder Feed  

NASA Technical Reports Server (NTRS)

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.

Zaplatynsky, Isidor

1988-01-01

247

21 CFR 866.2160 - Coagulase plasma.  

Code of Federal Regulations, 2010 CFR

...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...

2010-04-01

248

Control of impurities in toroidal plasma devices  

DOEpatents

A method and apparatus for plasma impurity control in closed flux plasma systems such as Tokamak reactors is disclosed. Local axisymmetrical injection of hydrogen gas is employed to reverse the normally inward flow of impurities into the plasma.

Ohkawa, Tihiro (La Jolla, CA)

1980-01-01

249

Drift waves in rotating plasmas  

SciTech Connect

The stability of the electron drift wave is investigated in the presence of E x B plasma rotation typical of the central cell plasma in tandem mirrors. It is shown that a rotationally-driven drift wave may occur at low azimuthal mode numbers. Conditions for rotational instabilities are derived. Quasilinear formulas are given for the anomalous transport associated with the unstable fluctuations.

Horton, W.; Liu, J.

1983-09-01

250

Biocompatibility of plasma nanostructured biopolymers  

NASA Astrophysics Data System (ADS)

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.

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

2013-07-01

251

On Imaging of Plasma Turbulence  

Microsoft Academic Search

We discuss aspects of imaging of plasma turbulence, taking the standpoint that the imaging is a path for induction of law from complex signals. An example of induction of symbol from signals is illustrated. Then the image of plasma turbulence is extended, putting an emphasis on the identification of the nonlinear interaction in turbulence. By employing the bipspectral method, magnitudes

K. Itoh; A. Fujisawa; Y. Nagashima; S.-I. Itoh; M. Yagi; P. H. Diamond; A. Fukuyama; K. Hallatschek

2008-01-01

252

Plasma chemistry and organic synthesis  

NASA Technical Reports Server (NTRS)

The characteristic features of chemical reactions using low temperature plasmas are described and differentiated from those seen in other reaction systems. A number of examples of applications of plasma chemistry to synthetic reactions are mentioned. The production of amino acids by discharge reactions in hydrocarbon-ammonia-water systems is discussed, and its implications for the origins of life are mentioned.

Tezuka, M.

1980-01-01

253

Programable Plasma-Spray System  

NASA Technical Reports Server (NTRS)

NASA-funded research led to development of automated plasma-spray system programable and reproducible. System utilizes standard plasma-spray equipment with noncoherent light-measuring system and microprocessor. System monitors and controls surface contours and coating thickness. Other advantages of system are consistant coating reproducibility, exact blending and feathering operations, ability to handle complex shapes and ease of changing spray parameters.

Fetheroff, C. W.; Derkacs, T.; Matay, I. M.; Toth, I.

1982-01-01

254

Plasma thrusters development in France  

Microsoft Academic Search

This paper presents an overview of the FRENCH plasma propulsion activities. The main existing and future projects are described. The field of application of plasma propulsion is the station keeping and the orbit raising of geostationary telecommunication satellites (STENTOR) and the transfer of interplanetary vehicles such as Mars Sample Return.The works done in the frame of the preparation of the

André Rolfo; Anne Cadiou; O. Secheresse; P. Dumazert; V. Gounot; X. Ragot; N. Mattei; T. Grassin; P. Garnero

2002-01-01

255

Model for resonant plasma probe.  

SciTech Connect

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.

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

2007-04-01

256

The quark-gluon plasma  

Microsoft Academic Search

I present various aspects of the physics of the quark-gluon plasma. Known properties of the transition from hadronic matter to the quark-gluon plasma are recalled. Progress in the phenomenology of ultra-relativistic heavy ion collisions is discussed on two examples. Some recent theoretical developments are mentioned.

Jean-Paul Blaizot

1993-01-01

257

EDITORIAL: Focus on Plasma Medicine  

Microsoft Academic Search

'Plasma Healthcare' is an emerging interdisciplinary research topic of rapidly growing importance, exploring considerable opportunities at the interface of plasma physics, chemistry and engineering with life sciences. Some of the scientific discoveries reported so far have already demonstrated clear benefits for healthcare in areas of medicine, food safety, environmental hygiene, and cosmetics. Examples include ongoing studies of prion inactivation, chronic

G. E. Morfill; M. G. Kong; J. L. Zimmermann

2009-01-01

258

Inductively Coupled Discharge Plasma Accelerator  

Microsoft Academic Search

Summary form only given. Electromagnetic acceleration for generating an electrically neutral, high flux plasma beam and a system for carrying out this method are studied for the semiconductor etching process having no charging damage and space missions. In the capacitively coupled discharge plasma accelerator, a certain amount of electrode sputtering is inevitable from the ion bombardment flux. This causes serious

V. N. Volynets; Yu. N. Tolmachev; V. G. Pashkovsky; Jinwoo Yoo

2005-01-01

259

Hollow Plasma in a Solenoid  

SciTech Connect

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.

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

2010-11-30

260

Collective quantum scattering in plasma  

Microsoft Academic Search

Collective quantum plasma effects in scattering of photons on electrons are derived. The generalization of Klein-Nishina scattering is obtained. The dependence of scattering on the collective plasma parameter and the ratio of the photon energy to the electron thermal energy is investigated.

V. N. Tsytovich

1996-01-01

261

Fluid Turbulence in Quantum Plasmas  

Microsoft Academic Search

Nonlinear fluid simulations are developed by us to investigate the properties of fully developed two-dimensional (2D) electron fluid turbulence in a very dense Fermi (quantum) plasma. We find that a 2D quantum electron plasma exhibits dual cascades, in which the electron number density cascades towards smaller turbulent scales, while the electrostatic potential forms larger scale eddies. The characteristic turbulent spectrum

Dastgeer Shaikh; P. K. Shukla

2007-01-01

262

Bremsstrahlung of hot quantum plasma  

Microsoft Academic Search

The classical Debye field is replaced by the respective quantum modification for a hot quantum plasma. The bremsstrahlung spectrum and the total bremsstrahlung intensity are investigated in detail. The results of numerical calculations are tabulatedvs. the characteristic parameterß=??0 \\/kT, where?0 is the plasma frequency and other symbols have their standard meaning. It is found that the deviations from the bremsstrahlung

J. Kvasnica; J. Horácek

1975-01-01

263

How to model quantum plasmas  

Microsoft Academic Search

Traditional plasma physics has mainly focused on regimes characterized by high temperatures and low densities, for which quantum-mechanical effects have virtually no impact. However, recent technological advances (particularly on miniaturized semiconductor devices and nanoscale objects) have made it possible to envisage practical applications of plasma physics where the quantum nature of the particles plays a crucial role. Here, I shall

Giovanni Manfredi

2005-01-01

264

Plasma-heating by induction  

NASA Technical Reports Server (NTRS)

Induction-heated plasma torch operates with an input of 1 Mw of direct current of which 71 percent is transferred to the plasma and the remainder is consumed by electrical losses in the system. Continuous operation of the torch should be possible for as long as 5,000 hours.

Harrington, K.; Thorpe, M. L.

1969-01-01

265

Plasma Porphyrins in the Porphyrias  

Microsoft Academic Search

Background: As an aid in the diagnosis and manage- ment of porphyria we have developed a method to fractionate and quantify plasma porphyrins and have evaluated its use in various porphyrias. Methods: We used HPLC with fluorometric detection to measure plasma concentrations of uroporphyrin I and III, heptacarboxyl III, hexacarboxyl III, pentacarboxyl III, and coproporphyrin I and III. We studied

J. Thomas Hindmarsh; Linda Oliveras; Donald C. Greenway

266

Gas lens laser produced plasma.  

PubMed

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

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

1989-07-01

267

Michigan Institute for Plasma Sci-  

E-print Network

in medicine has precedents. Thermal plasmas are used for cauteriza- tion, tissue ablation and tissue cutting of Direct Non-Thermal Plasma Interaction with Living Tissue Prof. Alexander Fridman Drexel University in medicine and on understanding the physical, chemical and biological mechanisms of the direct non-thermal

Shyy, Wei

268

Current drive in recombining plasma  

SciTech Connect

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.

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

2011-10-15

269

Filters for cathodic arc plasmas  

DOEpatents

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.

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

2002-01-01

270

Plasma evolution in the heliosheath  

NASA Astrophysics Data System (ADS)

Voyager 2 is now at 97 AU probably about 20 AU deep into the heliosheath. The Plasma Science experiment provides the only direct observations of plasma in the heliosheath. The plasma parameters depend on many factors; the solar wind source, the motions of the termination shock, and the influence of the interstellar medium among them. I will present the most recent plasma observations. Plasma speeds observed at Voyager 2 have decreased slowly across the heliosheath and remain well above those inferred at Voyager 1. The Voyager 2 flow angles continue to increase with large flows in the T than N directions (RTN coordinates). The density and temperature have decreased across the heliosheath until the beginning of 2011; since then the density has increased by a factor of 2 and the speed and temperature have also increased.

Richardson, J. D.

2011-12-01

271

Current Drive in Recombining Plasma  

SciTech Connect

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.

P.F. Schmit and N.J. Fisch

2012-05-15

272

Helicon plasma thruster discharge model  

SciTech Connect

By considering particle, momentum, and energy balance equations, we develop a semi-empirical quasi one-dimensional analytical discharge model of radio-frequency and helicon plasma thrusters. The model, which includes both the upstream plasma source region as well as the downstream diverging magnetic nozzle region, is compared with experimental measurements and confirms current performance levels. Analysis of the discharge model identifies plasma power losses on the radial and back wall of the thruster as the major performance reduction factors. These losses serve as sinks for the input power which do not contribute to the thrust, and which reduce the maximum plasma density and hence propellant utilization. With significant radial plasma losses eliminated, the discharge model (with argon) predicts specific impulses in excess of 3000?s, propellant utilizations above 90%, and thruster efficiencies of about 30%.

Lafleur, T., E-mail: trevor.lafleur@lpp.polytechnique.fr [Laboratoire de Physique des Plasmas, CNRS, Sorbonne Universités, UPMC Univ Paris 06, Univ Paris-Sud, Ecole Polytechnique, 91128 Palaiseau, France and ONERA - The French Aerospace Lab, 91120 Palaiseau (France)

2014-04-15

273

Resonant-cavity antenna for plasma heating  

DOEpatents

This invention relates generally to a method and apparatus for transferring energy to a plasma immersed in a magnetic field, and relates particularly to an apparatus for heating a plasma of low atomic number ions to high temperatures by transfer of energy to plasma resonances, particularly the fundamental and harmonics of the ion cyclotron frequency of the plasma ions. This invention transfers energy from an oscillating radio-frequency field to a plasma resonance of a plasma immersed in a magnetic field.

Perkins, F.W. Jr.; Chiu, S.C.; Parks, P.; Rawls, J.M.

1984-01-10

274

Aerospace applications of pulsed plasmas  

NASA Astrophysics Data System (ADS)

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.

Starikovskiy, Andrey

2012-10-01

275

Experimental plasma research project summaries  

NASA Astrophysics Data System (ADS)

This is the latest in a series of Project Summary books that date back to 1976. It is the first after a hiatus of several years. They are published to provide a short description of each project supported by the Experimental Plasma Research Branch of the Division of Applied Plasma Physics in the Office of Fusion Energy. The Experimental Plasma Research Branch seeks to provide a broad range of experimental data, physics understanding, and new experimental techniques that contribute to operation, interpretation, and improvement of high temperature plasma as a source of fusion energy. In pursuit of these objectives, the branch supports research at universities, DOE laboratories, other federal laboratories, and industry. About 70 percent of the funds expended are spent at universities and a significant function of this program is the training of students in fusion physics. The branch supports small- and medium-scale experimental studies directly related to specific critical plasma issues of the magnetic fusion program. Plasma physics experiments are conducted on transport of particles and energy within plasma. Additionally, innovative approaches for operating, controlling, and heating plasma are evaluated for application to the larger confinement devices of the magnetic fusion program. New diagnostic approaches to measuring the properties of high temperature plasmas are developed to the point where they can be applied with confidence on the large-scale confinement experiments. Atomic data necessary for impurity control, interpretation of diagnostic data, development of heating devices, and analysis of cooling by impurity ion radiation are obtained. The project summaries are grouped into the three categories of plasma physics, diagnostic development, and atomic physics.

1992-06-01

276

Meter scale plasma source for plasma wakefield experiments  

SciTech Connect

High accelerating gradients generated by a high density electron beam moving through plasma has been used to double the energy of the SLAC electron beam [1]. During that experiment, the electron current density was high enough to generate its own plasma without significant head erosion. In the newly commissioned FACET facility at SLAC, the peak current will be lower and without pre-ionization, head erosion will be a significant challenge for the planned experiments. In this work we report on our design of a meter scale plasma source for these experiments to effectively avoid the problem of head erosion. The plasma source is based on a homogeneous metal vapor gas column that is generated in a heat pipe oven [2]. A lithium oven over 30 cm long at densities over 10{sup 17} cm{sup -3} has been constructed and tested at UCLA. The plasma is then generated by coupling a 10 TW short pulse Ti:Sapphire laser into the gas column using an axicon lens setup. The Bessel profile of the axicon setup creates a region of high intensity that can stretch over the full length of the gas column with approximately constant diameter. In this region of high intensity, the alkali metal vapor is ionized through multi-photon ionization process. In this manner, a fully ionized meter scale plasma of uniform density can be formed. Methods for controlling the plasma diameter and length will also be discussed.

Vafaei-Najafabadi, N.; Shaw, J. L.; Marsh, K. A.; Joshi, C.; Hogan, M. J. [Department of Electrical Engineering, University of California Los Angeles, Los Angeles, CA 90095 (United States); SLAC National Accelerator Laboratory, Menlo Park, CA 94025 (United States)

2012-12-21

277

Surface plasma source with anode layer plasma accelerator  

SciTech Connect

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.

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

2012-02-15

278

Meter scale plasma source for plasma wakefield experiments  

NASA Astrophysics Data System (ADS)

High accelerating gradients generated by a high density electron beam moving through plasma has been used to double the energy of the SLAC electron beam [1]. During that experiment, the electron current density was high enough to generate its own plasma without significant head erosion. In the newly commissioned FACET facility at SLAC, the peak current will be lower and without pre-ionization, head erosion will be a significant challenge for the planned experiments. In this work we report on our design of a meter scale plasma source for these experiments to effectively avoid the problem of head erosion. The plasma source is based on a homogeneous metal vapor gas column that is generated in a heat pipe oven [2]. A lithium oven over 30 cm long at densities over 1017 cm-3 has been constructed and tested at UCLA. The plasma is then generated by coupling a 10 TW short pulse Ti:Sapphire laser into the gas column using an axicon lens setup. The Bessel profile of the axicon setup creates a region of high intensity that can stretch over the full length of the gas column with approximately constant diameter. In this region of high intensity, the alkali metal vapor is ionized through multi-photon ionization process. In this manner, a fully ionized meter scale plasma of uniform density can be formed. Methods for controlling the plasma diameter and length will also be discussed.

Vafaei-Najafabadi, N.; Shaw, J. L.; Marsh, K. A.; Joshi, C.; Hogan, M. J.

2012-12-01

279

Solid state plasmas  

E-print Network

Magnetic fusion devices operate at regimes characterized by extremely high temperatures and low densities, for which the charged particles motion is well described by classical mechanics. This is not true, however, for solid-state metallic objects: their density approaches $10^{28} \\rm m^{-3}$, so that the average interparticle distance is shorter than the de Broglie wavelength, which characterizes the spread of the electron wave function. Under these conditions, the conduction electrons behave as a true quantum plasma even at room temperature. Here, we shall illustrate the impact of quantum phenomena on the electron dynamics in metallic objects of nanometric size, particularly thin metallic films excited by short laser pulses. Further, we will discuss more recent results on regimes that involve spin and relativistic effects.

Manfredi, Giovanni

2014-01-01

280

Magnetospheric space plasma investigations  

NASA Technical Reports Server (NTRS)

A time dependent semi-kinetic model that includes self collisions and ion-neutral collisions and chemistry was developed. Light ion outflow in the polar cap transition region was modeled and compared with data results. A model study of wave heating of O+ ions in the topside transition region was carried out using a code which does local calculations that include ion-neutral and Coulomb self collisions as well as production and loss of O+. Another project is a statistical study of hydrogen spin curve characteristics in the polar cap. A statistical study of the latitudinal distribution of core plasmas along the L=4.6 field line using DE-1/RIMS data was completed. A short paper on dual spacecraft estimates of ion temperature profiles and heat flows in the plasmasphere ionosphere system was prepared. An automated processing code was used to process RIMS data from 1981 to 1984.

Comfort, Richard H.; Horwitz, James L.

1994-01-01

281

Research in plasma physics  

NASA Technical Reports Server (NTRS)

Three aspects of barium ion cloud dynamics are discussed. First, the effect of the ratio of ion cloud conductivity to background ionospheric conductivity on the motion of barium ion clouds is investigated and compared with observations of barium ion clouds. This study led to the suggestion that the conjugate ionosphere participates in the dynamics of barium ion clouds. Second, analytic work on the deformation of ion clouds is presented. Third, a linearized stability theory was extended to include the effect of the finite extent of an ion cloud, as well as the effect of the ratio of ion cloud to ionospheric conductivities. The stability properties of a plasma with contra-streaming ion beams parallel to a magnetic field are investigated. The results are interpreted in terms of parameters appropriate for collisionless shock waves. It is found that this particular instability can be operative only if the up-stream Alfven Mach number exceeds 5.5.

1973-01-01

282

Dusty plasma ring model  

NASA Astrophysics Data System (ADS)

A model of a dusty plasma (Yukawa) ring is presented. We consider n identical particles confined in a two-dimensional (2D) annular potential well and interacting through a Debye (i.e. Yukawa or screened Coulomb) potential. Equilibrium configurations are computed versus n, the Debye shielding parameter and the trap radius. When the particle separation exceeds a critical value the particles form a 1D chain with a ring topology. Below the critical separation the zigzag instability gives a 2D configuration. Computed critical separations are shown to agree well with a theoretical prediction for the zigzag threshold. Normal mode spectra for 1D rings are computed and found to be in excellent agreement with the longitudinal and transverse dispersion relations for unbounded straight chains. When the longitudinal and transverse dispersion relations intersect we observe a resonance due to the finite curvature of the ring.

Sheridan, T. E.

2009-12-01

283

NCSX Plasma Heating Methods  

SciTech Connect

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.

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

2008-01-18

284

Global simulations of plasma turbulence in laboratory plasmas  

NASA Astrophysics Data System (ADS)

The Global Braginskii Solver (GBS) code has been developed in the last few years to simulate plasma turbulence in laboratory plasmas [1]. By solving the drift-reduced Braginkii equation in magnetic configurations of increasing complexity, from linear devices to the Simple Magnetized Toroidal (SMT) configuration, GBS performs non-linear self-consistent global three-dimensional simulations of the plasma dynamics, as the result of the interplay among the plasma source, the turbulent transport, and the plasma losses at the vessel. This gradual approach has allowed gaining a deep understanding of the turbulence dynamics, by identifying the instabilities responsible for driving plasma turbulence and to estimate the turbulence saturation amplitude. In particular, simulation results have pointed out the need of global simulations to correctly represent the dynamics of laboratory plasmas, as well as the importance of not separating fluctuations and equilibrium quantities. A code validation development project has been conducted side by side with the GBS development [2]. Such validation project has lead to the establishment of a rigorous methodology to carry out experiment-simulation comparison, and has allowed quantifying precisely the level of agreement between the GBS results and the experimental data from the TORPEX experiment at CRPP. [1] P. Ricci, B.N. Rogers, S. Brunner, Phys. Rev. Lett. 100, 225002 (2008); P. Ricci and B. N. Rogers, Phys. Rev. Lett. 104, 145001 (2010); B. N. Rogers and P. Ricci, Phys. Rev. Lett. 104, 225002 (2010); B. Li et al., Phys. Rev. E 83, 056406 (2011). [2] P. Ricci et al, Phys. Plasmas 16, 055703 (2009); P. Ricci et al., Phys. Plasmas 18, 032109 (2011).

Ricci, P.; Fasoli, A.; Furno, I.; Jolliet, S.; Loizu, J.; Mosetto, A.; Rogers, B. N.; Theiler, C.

2012-04-01

285

Plasma Dark Current in Self-Ionized Plasma Wakefield Accelerators  

SciTech Connect

Evidence of particle trapping has been observed in a beam driven Plasma Wake Field Accelerator (PWFA) experiment, E164X, conducted at the Stanford Linear Accelerator Center by a collaboration which includes USC, UCLA and SLAC. Such trapping produces plasma dark current when the wakefield amplitude is above a threshold value and may place a limit on the maximum acceleration gradient in a PWFA. Trapping and dark current are enhanced when in an ionizing plasma, that is self-ionized by the beam. Here we present experimental results.

Oz, E.; Deng, S.; Katsouleas, T.; Muggli, P.; /Southern California U.; Iverson, R.; Johnson, D.K.; Krejcik, P.; O'Connell, C.; Siemann, R.H.; Walz, D.; /SLAC; Clayton,; Huang, C.; Joshi, C.; Lu, W.; Marsh, K.A.; Mori, W.B.; Zhou, M.; /UCLA

2006-01-30

286

Negative Plasma Densities Raise Questions  

SciTech Connect

Nearly all the matter encountered on Earth is either a solid, liquid, or gas. Yet plasma-the fourth state of matter-comprises more than 99 percent of the visible universe. Understanding the physical characteristics of plasmas is important to many areas of scientific research, such as the development of fusion as a clean, renewable energy source. Lawrence Livermore scientists study the physics of plasmas in their pursuit to create fusion energy, because plasmas are an integral part of that process. When deuterium and tritium are heated to the extreme temperatures needed to achieve and sustain a fusion reaction (about 100 million degrees), the electrons in these light atoms become separated from the nuclei. This process of separation is called ionization, and the resulting collection of negatively charged free electrons and positively charged nuclei is known as a plasma. Although plasmas and gases have many similar properties, plasmas differ from gases in that they are good conductors of electricity and can generate magnetic fields. For the past decade, x-ray laser interferometry has been used in the laboratory for measuring a plasma's index of refraction to determine plasma density. (The index of refraction for a given material is defined as the wavelength of light in a vacuum divided by the wavelength of light traveling through the material.) Until now, plasma physicists expected to find an index of refraction less than one. Researchers from Livermore and Colorado State University recently conducted experiments on aluminum plasmas at the Laboratory's COMET laser facility and observed results in which the index of refraction was greater than one. This surprising result implied a negative electron density. Livermore physicist Joseph Nilsen and his colleagues from Livermore and the University of Notre Dame have performed sophisticated calculations to explain this phenomenon. Previously, researchers believed that only free electrons contributed to the index of refraction. Nilsen and his colleagues posit that bound electrons attached to the ions in plasmas can greatly affect the index of refraction and make it greater than one. Furthermore, if the effect of bound electrons is ignored when analyzing experimental results from x-ray interferometry, the electron density of plasmas may be indeterminate or significantly under- or overestimated.

Hazi, A

2006-01-26

287

Liquid injection plasma deposition method and apparatus  

DOEpatents

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.

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

1999-05-25

288

Liquid injection plasma deposition method and apparatus  

DOEpatents

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.

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

1999-01-01

289

Atmospheric-pressure plasma jet  

DOEpatents

Atmospheric-pressure plasma jet. A .gamma.-mode, resonant-cavity plasma discharge that can be operated at atmospheric pressure and near room temperature using 13.56 MHz rf power is described. Unlike plasma torches, the discharge produces a gas-phase effluent no hotter than 250.degree. C. at an applied power of about 300 W, and shows distinct non-thermal characteristics. In the simplest design, two concentric cylindrical electrodes are employed to generate a plasma in the annular region therebetween. A "jet" of long-lived metastable and reactive species that are capable of rapidly cleaning or etching metals and other materials is generated which extends up to 8 in. beyond the open end of the electrodes. Films and coatings may also be removed by these species. Arcing is prevented in the apparatus by using gas mixtures containing He, which limits ionization, by using high flow velocities, and by properly shaping the rf-powered electrode. Because of the atmospheric pressure operation, no ions survive for a sufficiently long distance beyond the active plasma discharge to bombard a workpiece, unlike low-pressure plasma sources and conventional plasma processing methods.

Selwyn, Gary S. (Los Alamos, NM)

1999-01-01

290

Plasma Treatments and Biomass Gasification  

NASA Astrophysics Data System (ADS)

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.

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

2012-02-01

291

Plasma medicine: an introductory review  

NASA Astrophysics Data System (ADS)

This introductory review on plasma health care is intended to provide the interested reader with a summary of the current status of this emerging field, its scope, and its broad interdisciplinary approach, ranging from plasma physics, chemistry and technology, to microbiology, biochemistry, biophysics, medicine and hygiene. Apart from the basic plasma processes and the restrictions and requirements set by international health standards, the review focuses on plasma interaction with prokaryotic cells (bacteria), eukaryotic cells (mammalian cells), cell membranes, DNA etc. In so doing, some of the unfamiliar terminology—an unavoidable by-product of interdisciplinary research—is covered and explained. Plasma health care may provide a fast and efficient new path for effective hospital (and other public buildings) hygiene—helping to prevent and contain diseases that are continuously gaining ground as resistance of pathogens to antibiotics grows. The delivery of medically active 'substances' at the molecular or ionic level is another exciting topic of research through effects on cell walls (permeabilization), cell excitation (paracrine action) and the introduction of reactive species into cell cytoplasm. Electric fields, charging of surfaces, current flows etc can also affect tissue in a controlled way. The field is young and hopes are high. It is fitting to cover the beginnings in New Journal of Physics, since it is the physics (and non-equilibrium chemistry) of room temperature atmospheric pressure plasmas that have made this development of plasma health care possible.

Kong, M. G.; Kroesen, G.; Morfill, G.; Nosenko, T.; Shimizu, T.; van Dijk, J.; Zimmermann, J. L.

2009-11-01

292

Laser-induced plasma temperature  

NASA Astrophysics Data System (ADS)

It is of great importance to explore the evolution of laser-induced plasma (LIP) properties, especially plasma temperature, with regard to variations of experiment conditions in both theoretical study and routine applications. By investigating the influence of various factors on plasma temperature, one can gain knowledge about the processes in plasma and adjust experimental conditions to obtain optimum analytical performance. Herein the fundamental theories and calculation methods of LIP temperature via spectroscopic approaches are briefly reviewed. Its temporal and spatial evolutions together with several influencing factors are discussed, such as laser parameters, ambient surrounding, and physical & chemical properties of the sample. The results summarized exhibit the general trend that LIP temperature increases with increasing laser wavelength, pulse width, laser energy, background gas pressure, and sample hardness. On the other hand, it decreases with time elapsing and distance from sample surface. Moreover, plasma temperature generated in argon surrounding is higher than that in other gas species, and the rank of temperature values generated from different samples exhibits a general tendency of Cu > Fe > Ni ? Al ? glass ? rock. Additionally, LIP temperature tends to increase as lens focal point approaches sample surface, and the plasma confinement effect in sample cavity is significant in altering plasma temperature. Various explanations are given to interpret these temperature behaviors.

Zhang, Shudi; Wang, Xiaohua; He, Miaohong; Jiang, Yunbin; Zhang, Bochao; Hang, Wei; Huang, Benli

2014-07-01

293

HUMAN PLASMA ALPHA 2-MACROGLOBULIN  

PubMed Central

Activation of plasma kallikrein arginine esterase activity by kaolin resulted in peak activity at 1 min of incubation and a 50% reduction in activity at 5 min in normal plasma, and 30% reduction in the plasma of patients with hereditary angioneurotic edema who lacked the C1 inactivator. The peak esterolytic activity was inhibited by soybean trypsin inhibitor whereas the 5 min activity was resistant to this inhibitor. Acid treatment of normal and hereditary angioneurotic edema plasma destroyed the factor responsible for the fall in esterase activity at 5 min and the factor which rendered the esterase resistant to soybean trypsin inhibitor. Purified ?2-macroglobulin inhibited approximately 50% of the TAMe esterase activity of purified plasma kallikrein without changing its activity toward basic amino acid esters. The interaction between the ?2-macroglobulin and kallikrein resulted in alterations in the gel filtration chromatographic pattern of the TAMe esterase and biologic activity of kallikrein, indicating that kallikrein was bound to the ?2-macroglobulin. The TAMe esterase activity of this complex, isolated by column chromatography, was resistant to C1 inactivator and SBTI. Studies of incubation mixtures of kallikrein, ?2-macroglobulin and C1 inactivator suggested that these inhibitors compete for the enzyme, and that the ?2-macroglobulin partially protects the esterase activity of kallikrein from C1 inactivator. The ?2-macroglobulin isolated from kaolin-activated plasma possessed 240 times the esterolytic activity of the ?2-macroglobulin purified from plasma treated with inhibitors of kallikrein and of its activation. The ?2-macroglobulin blocked the uterine-containing activity and vascular permeability-inducing effects of plasma kallikrein. These studies suggest that the ?2-macroglobulin is a major plasma inhibitor of kallikrein and provide a new example of an interrelationship between the coagulation, fibrinolytic, and kallikrein enzyme systems. PMID:4101346

Harpel, Peter C.

1970-01-01

294

Surface plasma source with saddle antenna radio frequency plasma generator  

SciTech Connect

A prototype RF H{sup -} 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{sup -} 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.

Dudnikov, V.; Johnson, R. P. [Muons, Inc., Batavia, Illinios 60510 (United States); Murray, S.; Pennisi, T.; Piller, C.; Santana, M.; Stockli, M.; Welton, R. [ORNL, Oak Ridge, Tennessee 37831 (United States)

2012-02-15

295

Plasma acceleration processes in an ablative pulsed plasma thruster  

SciTech Connect

Plasma acceleration processes in an ablative pulsed plasma thruster (APPT) were investigated. APPTs are space propulsion options suitable for microspacecraft, and have recently attracted much attention because of their low electric power requirements and simple, compact propellant system. The plasma acceleration mechanism, however, has not been well understood. In the present work, emission spectroscopy, high speed photography, and magnetic field measurements are conducted inside the electrode channel of an APPT with rectangular geometry. The successive images of neutral particles and ions give us a comprehensive understanding of their behavior under electromagnetic acceleration. The magnetic field profile clarifies the location where the electromagnetic force takes effect. As a result, it is shown that high density, ablated neutral gas stays near the propellant surface, and only a fraction of the neutrals is converted into plasma and electromagnetically accelerated, leaving the residual neutrals behind.

Koizumi, Hiroyuki; Noji, Ryosuke; Komurasaki, Kimiya; Arakawa, Yoshihiro [Department of Aeronautics and Astronautics, University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Department of Advanced Energy, University of Tokyo, 5-1-5, Kashiwanoha, Kashiwa, Chiba 277-8561 (Japan); Department of Aeronautics and Astronautics, University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan)

2007-03-15

296

Surface plasma source with saddle antenna radio frequency plasma generator.  

PubMed

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

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

2012-02-01

297

Surface plasma source with saddle antenna radio frequency plasma generatora)  

NASA Astrophysics Data System (ADS)

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.

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

2012-02-01

298

The Absence of Plasma in"Spark Plasma Sintering"  

SciTech Connect

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.

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

299

Interactions between satellites and plasma  

NASA Technical Reports Server (NTRS)

The interactions of a spacecraft with the surrounding, streaming plasma were determined by the following effects: the fade out of the plasma in the wake of the probe, the emission of photoelectrons and secondary electrons, the differential charging of the surface of the probe, and a spatial potential distribution in the vicinity of the space probe. These effects and their importance are discussed and following plasma conditions are considered: (1) geostationary satellite orbits; (2) in the solar wind (HELIOS mission); and (3) in the ionosphere at an altitude of 250 km (the projected OSV on Spacelab). The fundamental models are reviewed.

Isensee, U.; Lehr, W.; Maassberg, H.

1984-01-01

300

Laser plasma interactions in hohlraums  

SciTech Connect

Lasers plasma instabilities are an important constraint in x-ray driven inertial confinement fusion. In hohlraums irradiated with 1.06 {mu}m light on the Shiva laser, plasma instabilities were extremely deleterious, driving the program to the use of shorter wavelength light. Excellent coupling has been achieved in hohlraums driven with 0.35 {mu}m light on the Nova laser. Considerable attention is being given to the scaling of this excellent coupling to the larger hohlraums for an ignition target. Various instability control mechanisms such as large plasma wave damping and laser beam incoherence are discussed, as well as scaling experiments to check the instability levels.

Kruer, W.L.

1994-10-05

301

Dust confinement in anodic plasmas  

SciTech Connect

Experiments on dust confinement in a magnetized plasma region in front of a small positively biased electrode are analyzed. The axial confinement of d = 1{mu}m particles can be quantitatively described by a balance of ion drag and electric field force. Radial confinement is due to strong electric fields. It is demonstrated that this anodic plasma has a distinctly different discharge mechanism from fireballs with ionizing double layers. The plasma is stable against potential relaxations but shows a strong ion cyclotron mode in the shear layer at the anode edge.

Piel, A.; Trottenberg, T.; Block, D. [IEAP, Christian-Albrechts-University, D-24098 Kiel (Germany)

2005-10-31

302

Critical Point in Complex Plasmas  

SciTech Connect

The occurrence of liquid-vapor phase transition and the possible existence of a critical point in complex plasmas--systems that consist of charged micrograins in a neutralizing plasma background--is investigated theoretically. An analysis based on the consideration of the intergrain interaction potential suggests that under certain conditions systems near and at the critical point should be observable. Measurements under microgravity conditions would appear to be required. The analysis aims at determining the plasma parameter regime most suitable for planned experimental investigations.

Khrapak, S.A.; Morfill, G.E.; Ivlev, A.V.; Thomas, H.M. [Max-Planck-Institut fuer Extraterrestrische Physik, D-85741 Garching (Germany); Beysens, D.A. [CEA ESPCI, 10 rue Vauquelin, 75231 Paris CEDEX 5 (France); Zappoli, B. [CNES, 18 Avenue Edouard Belin, 31401 Toulouse CEDEX (France); Fortov, V.E.; Lipaev, A.M.; Molotkov, V.I. [Institute for High Energy Densities, Russian Academy of Sciences, 125412 Moscow (Russian Federation)

2006-01-13

303

Radioimmunoassay of ACTH in plasma  

PubMed Central

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

Berson, Solomon A.; Yalow, Rosalyn S.

1968-01-01

304

Plasma Deposition of Amorphous Silicon  

NASA Technical Reports Server (NTRS)

Strongly adhering films of silicon are deposited directly on such materials as Pyrex and Vycor (or equivalent materials) and aluminum by a non-equilibrium plasma jet. Amorphous silicon films are formed by decomposition of silicon tetrachloride or trichlorosilane in the plasma. Plasma-jet technique can also be used to deposit an adherent silicon film on aluminum from silane and to dope such films with phosphorus. Ability to deposit silicon films on such readily available, inexpensive substrates could eventually lead to lower cost photovoltaic cells.

Calcote, H. F.

1982-01-01

305

The Diagnostics of the External Plasma for the Plasma Rocket  

NASA Technical Reports Server (NTRS)

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.

Karr, Gerald R.

1997-01-01

306

Pulse-discharge plasmas for plasma-accelerator applications  

NASA Astrophysics Data System (ADS)

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.

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

2012-12-01

307

Plasma Jet Diagnostic for Runaway Electron Beam-Plasma Interaction  

NASA Astrophysics Data System (ADS)

FAR-TECH's recently developed C60/C plasma jet has the potential to rapidly and significantly increase electron density, deep into tokamak plasma, hence to change the `critical electric field' as well as the runaway electrons (REs) collisional drag, during different phases of REs dynamics. Suitably chosen visible/UV lines emitted by the injected C ions can then be used for line intensity quantitative spectroscopy, allowing the diagnostic of the RE beam-plasma interaction. The C60 delivered in ˜1 ms by the prototype plasma jet system, estimated to be ˜75 mg, carries ˜4x10^21 C atoms and ˜2.4x10^22 electrons, and would lead to an electron density ne˜2.4x10^21 m-3, i.e. ˜60 times larger than typical DIII-D pre-disruption value (ne0 4x10^19 m-3). While the prototype's C60/C plasma jet mass is not sufficient to achieve the Rosenbluth electron density in DIII-D, it delivers a total number of electrons ˜5 times larger than that of the Ar pellet, with the advantage of a much faster response and precisely chosen delivery time. We will present several proposed diagnostic schemes using rapid C60/C plasma jet injection capability in different phases of the discharge in DIII-D.

Bogatu, I. N.; Thompson, J. R.; Galkin, S. A.; Kim, J. S.; Brockington, S.; Case, A.; Messer, S. J.; Witherspoon, F. D.

2012-10-01

308

SYLLABUS: PHYSICS 8120 PLASMA PHYSICS FALL 2007  

E-print Network

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

Wiita, Paul J.

309

Recent developments in DBD plasma flow control  

NASA Astrophysics Data System (ADS)

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.

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

2013-10-01

310

ISRAELI PLASMA SCIENCE AND TECHNOLOGY ASSOCIATION  

E-print Network

, plasma processing, fusion research, sources of radiation and particle beams, pulsed power, or other basic and applied aspects of plasmas. Many processes in technologies that involve plasmas occur naturally in space for conversion of laser energy to nuclear energy, bridging chemistry and plasma physics. The two other invited

311

Nano-Fabrication by Cathodic Plasma Electrolysis  

Microsoft Academic Search

Cathodic plasma electrolytic (CPE) techniques are new groups of coating processes, which can be used for fabrication of nanostructured layers on surface of a wide range of metallic substrates. The most exciting visible feature of these atmospheric-based plasma techniques is continuous sparking on processed surface inside an electrolyte. Unlike the anodic part of plasma electrolysis (usually known as plasma electrolytic

M. Aliofkhazraei; A. Sabour Rouhaghdam; P. Gupta

2011-01-01

312

Basic requirements for plasma sources in medicine  

Microsoft Academic Search

Plasma medicine is a new medical field with first very promising practical studies. However, basic research needs to be done to minimize risk and provide a scientific fundament for medical therapies. Therapeutic application of plasmas at or in the human body is a challenge both for medicine and plasma physics. Today, concepts of tailor-made plasma sources which meet the technical

K.-D. Weltmann; Th. von Woedtke

2011-01-01

313

DENSITY LIMITS IN TOROIDAL PLASMAS MARTIN GREENWALD  

E-print Network

DENSITY LIMITS IN TOROIDAL PLASMAS MARTIN GREENWALD MIT - PLASMA SCIENCE & FUSION CENTER Presented on plasma pressure, current, and density · Understanding these limits and their implications has always been an active area of research #12;DENSITY LIMITS - AN IMPORTANT ISSUE FOR MAGNETIC FUSION · 2 DTR n v · Plasma

Greenwald, Martin

314

Princeton Plasma Physics Laboratory NSTX Experimental Proposal  

E-print Network

with CHI is the major goal of this XP. 3: Thermal Quench Loading: The complete thermal energy of the plasmaPrinceton Plasma Physics Laboratory NSTX Experimental Proposal Title: Exploration of Fast Discharge the existing CHI hardware to initiate fast plasma- shutdowns in NSTX. A standard inductive plasma with NBI

Princeton Plasma Physics Laboratory

315

Laser Assisted Plasma Arc Welding  

SciTech Connect

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.

FUERSCHBACH,PHILLIP W.

1999-10-05

316

Plasma in the Heliosheath (Invited)  

NASA Astrophysics Data System (ADS)

The Voyager 2 plasma experiment has directly measured the heliosheath plasma since the termination shock crossing in 2007. This paper presents the data obtained up to December 2013. The flow direction has turned about 55 degrees in the RT plane, so some data are lost because of the angular response of the instrument. However, the plasma properties in the heliosheath fluctuate rapidly which allows much data to be recovered despite the high flow angles. The recent data show a continued slowing in the plasma speed and a turning tailward, with flow angles much larger in the RT than RN planes. The density increased in 2011 and has remained high; the flux has recovered to near the level observed at 1 AU. The temperature has remained near 50,000 K. These observations will be compared to V1 and model results.

Richardson, J. D.

2013-12-01

317

Conductivity of a relativistic plasma  

SciTech Connect

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.

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

1989-03-01

318

Plasma cell balinitis of Zoon.  

PubMed

Superficial lesions of the glans penis can pose diagnostic difficulties. Plasma cell balanitis is such a condition and it may be confused clinically with erythroplasia of Queyrat. It is unresponsive to topical medication and curable only by circumcision. PMID:3801829

Murray, W J; Fletcher, M S; Yates-Bell, A J; Pryor, J P; Darby, A J; Packham, D A

1986-12-01

319

MHD stability of tokamak plasmas  

SciTech Connect

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.

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

1992-08-01

320

MHD stability of tokamak plasmas  

SciTech Connect

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.

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

1992-01-01

321

Plasma centrifuge development at INPE  

NASA Astrophysics Data System (ADS)

The plasma centrifuge is a device in which a fully ionized plasma column rotates at high angular velocities by means of crossed electric and magnetic fields. Ion angular rotation frequencies of 6.9 x 10,000 to 1.2 x 100,000 rad/s were measured for a carbon plasma, with an externally applied magnetic field of 0.09T. Isotopic enrichments of up to 390 percent for C-13 were measured at 6 cm radius. The steady state behavior of the fully ionized magnetized plasma in the vacuum arc centrifuge was theoretically investigated using a multiple species fluid model, which includes electromagnetic, pressure gradient, centrifugal and collisional forces in cylindrical geometry.

Bittencourt, J. A.; Delbosco, E.; Dallaqua, R. S.; Ludwig, G. O.

1987-07-01

322

Plasma fluoride and enamel fluorosis.  

PubMed

It is postulated that tissue fluid F concentrations are the primary determinants of flouride effects on bones and developing teeth and that these concentrations are dependent on, or mirrored by, blood plasma F. It has earlier been shown that the plasma F levels are dependent on the dietary F supply as well as on skeletal F concentration. Fasting and post-ingestion or postinjection plasma F levels have been determined in rats on F doses that cause different degrees of enamel fluorosis. The results indicate that temporary peak values rather than elevated fasting values are responsible for the occurrence of enamel fluorosis and that the peak values must approach about 10 muM in order to block enamel formation by the ameloblasts. The diagnostic and prognostic importance of plasma F determinations is discussed. PMID:1000344

Angmar-Månsson, B; Ericsson, Y; Ekberg, O

1976-11-24

323

Plasma Heating: An Advanced Technology  

NASA Technical Reports Server (NTRS)

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.

1994-01-01

324

Layered plasma polymer composite membranes  

DOEpatents

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 .gtoreq.2 and is the number of selective layers.

Babcock, Walter C. (Bend, OR)

1994-01-01

325

Plasma transport near material boundaries  

SciTech Connect

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.

Singer, C.E.

1985-06-01

326

TFTR plasma regimes  

SciTech Connect

Significant extensions in the TFTR plasma operating regimes have been achieved with additional heating-system capability, installation of a multishot pellet injector, and the development of an enhanced confinement regime. In ohmically heated pellet-fueled discharges characterized by highly peaked density profiles, enhancements in tau/sub E/ have resulted in n/sub e/(0)tau/sub E/(a)-values of 1.5 x 10/sup 20/ m/sup -3/s. In neutral-beam-heated discharges, an operating regime has been developed in which substantial improvements in energy confinement time and neutron source strength are observed. Ion temperatures of approx.20 keV and n/sub e/(0)tau/sub E/(a)T/sub i/(0)-values of 2 x 10/sup 20/ m/sup -3/s keV have been achieved. This enhanced confinement regime is characterized by high values of ..beta../sub p/ and low values of collisionality. The observed surface voltage, which is negative during beam injection, is compared with models including beam-driven and bootstrap currents.

Hawryluk, R.J.; Arunasalam, V.; Bell, M.G.; Bitter, M. Blanchard, W.R.; Bretz, N.L.; Budny, R.; Bush, C.E.; Callen, J.D. Cohen, S.A.

1987-02-01

327

Laser plasma thruster  

NASA Astrophysics Data System (ADS)

The laser plasma thruster (LPT) is a new microthruster for small satellites. We report on development and testing of a prototype LPT. Some advantages of the LPT are: thruster voltage 4 V, mass less than 1 kg, power-to-thrust ratio 10 kW/N, and Isp up to 1000 s. Typical thrust level is 250 ?N with PVC fuel. Thrust of 1 mN is expected with energetic fuel. The pre-prototype continuous-thrust experiment includes the laser mount and heat sink, lens mounts, and focusing mechanism, which are coupled to the target-material transport mechanism. The target material is applied to a transparent plastic tape, and the laser is focused on a series of tracks on the tape. The tape-drive hardware and laser-drive electronics are described. Design, construction, and calibration of the thrust stand are described. During continuous operation, the exhaust plume is deflected in the direction of the moving tape. When the laser is operated in pulsed mode, the exhaust plume is perpendicular to the tape (parallel to the optical axis). This provides some thrust-vector control. Measured thrust is 70 ?N with PVC fuel, and 550 ?N with energetic fuel, with a specific impulse of 350 s.

Luke, J. R.; Phipps, C. R.; McDuff, G. G.

328

Positron driven plasma wakefields  

NASA Astrophysics Data System (ADS)

The LHC is producing high-energy, high-charge proton bunches (1e11 protons at 1-7 TeV each) that could be used to accelerate ``witness'' electron bunches to TeV range eneregies via a plasma wakefield accelerator (PWFA). Simulations [1] suggest that a proton ``drive'' bunch is able to excite large wakefields if the bunch size is on the order of 100 ?m; however, the LHC paramters are currently on the 1 cm scale. SLAC'S FACET is able to supply positorn bunchs with the ideal parameters for driving a PWFA. Although at lower energy (2e10 positrons at 23 GeV each), initial simiulations in QuickPIC show that the physics of a positron drive bunch is very similar to that of a proton drive bunch. Differences in the physics arise from the mass difference: slower dephasing but faster transverse bunch evolution. Other considerations include driver head erosion and purity of the wakefield ion column. The physics of positive drivers for PWFA and the viability of this scheme for future high-energy colliders will be investigated at SLAC's FACET.[4pt] [1] Caldwell, et al. Nature Physics 5, 363 (2009).[0pt] [2] C.H. Huang, et al., J. Comp. Phys., 217(2), 658, (2006).

Pinkerton, S.; Shi, Y.; Huang, C.; An, W.; Mori, W. B.; Muggli, P.

2010-11-01

329

Welding arc plasma physics  

NASA Technical Reports Server (NTRS)

The problems of weld quality control and weld process dependability continue to be relevant issues in modern metal welding technology. These become especially important for NASA missions which may require the assembly or repair of larger orbiting platforms using automatic welding techniques. To extend present welding technologies for such applications, NASA/MSFC's Materials and Processes Lab is developing physical models of the arc welding process with the goal of providing both a basis for improved design of weld control systems, and a better understanding of how arc welding variables influence final weld properties. The physics of the plasma arc discharge is reasonably well established in terms of transport processes occurring in the arc column itself, although recourse to sophisticated numerical treatments is normally required to obtain quantitative results. Unfortunately the rigor of these numerical computations often obscures the physics of the underlying model due to its inherent complexity. In contrast, this work has focused on a relatively simple physical model of the arc discharge to describe the gross features observed in welding arcs. Emphasis was placed of deriving analytic expressions for the voltage along the arc axis as a function of known or measurable arc parameters. The model retains the essential physics for a straight polarity, diffusion dominated free burning arc in argon, with major simplifications of collisionless sheaths and simple energy balances at the electrodes.

Cain, Bruce L.

1990-01-01

330

Space Plasma Physics  

NASA Technical Reports Server (NTRS)

Dr. James L. Horwitz and R. Hugh Comfort's studies with the high altitude TIDE data have been progressing well. We concluded a study on the relationship of polar cap ion properties observed by TIDE near apogee with solar wind and IMF conditions. We found that in general H+ did not correlate as well as O+ with solar wind and IMF parameters. O+ density correlated(sub IMF), and Kp. At lower solar wind speeds, O+ density decreased with increasing latitude, but this trend was not observed at higher solar wind speeds. By comparing these results with results from other studies of O+ in different parts of the magnetosphere, we concluded that O+ ions often leave the ionosphere near the foot point of the cusp/cleft region, pass through the high-altitude polar cap lobes, and eventually arrive in the plasma sheet. We found that H+ outflows are a persistent feature of the polar cap and are not as dependent on the geophysical conditions; even classical polar wind models show H+ ions readily escaping owing to their low mass. Minor correlations with solar wind drivers were found; specifically, H+ density correlated best with IMF By, V(sub sw)B(sub IMF), and ESW(sub sw).

Wu, S. T.

2000-01-01

331

Dusty-Plasma Particle Accelerator  

NASA Technical Reports Server (NTRS)

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.

Foster, John E.

2005-01-01

332

Semiconductor Industry Plasma Processing Needs  

NASA Astrophysics Data System (ADS)

The plasma requirements of dry etch equipment used for advanced semiconductor process development and low cost semiconductor manufacturing are reviewed. Introduction of ArF (193nm) photolithography has resulted in increased demands on resist selectivity, increased sensitivity to plasma induced or exacerbated line edge roughness, and the introduction of novel hard and soft mask schemes. State of the art plasma processing chambers must be able to deliver low DC bias due to line edge roughness requirements with adequate ion/radical density to prevent loss of critical dimension control in deep features. These same systems may be required to operate in a high DC bias, low plasma density regime to achieve adequate etch rate on different films, and in many cases the system must be able to switch between low and high DC bias modes. The acceptable plasma density is limited by that necessary to provide adequate production of passivation agents necessary to achieve selectivity to ArF photoresists. Further limits on plasma density may be needed due to device and etch profile sensitivity to differential charging. The allowable DC bias may be limited to avoid damage to shallow implanted regions and thin gate. Decreases in gate length have increased sensitivity to non-anisotropic profiles, which in turn requires a minimum of DC bias to provide anisotropy. Particle sensitivity has resulted in a migration toward integrated plasma processing, putting additional demands on the stability and flexibility of the plasma equipment. State of the art plasma tooling must be capable of operating over a wide range of plasma densities, delivering both high and low DC bias, and provide RF stability over a wide range of wafer/chamber impedances. The increased uniformity requirements of 300 mm tools requires the anode and cathode potential be uniformly distributed over the entire surface, and that the plasma generation be as uniform as possible. Extended wet clean cycles have driven the need for integrated cleans, which also must be capable of removing deposited films uniformly over the chamber surface.

Wise, Richard; Panda, Siddhartha; Yan, Wendy

2003-10-01

333

Theory for Plasma Rocket Propulsion  

NASA Astrophysics Data System (ADS)

Electrical propulsion of rockets is developing potentially into the use of 3 different thrusters for future long-distance space missions that primarily involve plasma dynamics. These are the Magnetoplasmadynamic (MPD) Thruster, the Plasma Induction Thruster (PID), and the VASIMIR Thruster. The history of the development of electrical propulsion into these prospects and the current research of particularly the VASIMIR Thruster are reviewed. Theoretical questions that need to be addressed in that development are explored.

Grabbe, Crockett

2009-11-01

334

Optical diagnostics of dusty plasmas  

Microsoft Academic Search

The central topic of this thesis is dusty plasmas, in which particles are generated or injected. Such plasmas, when ignited in silane-based gas mixtures, are widely used in the semiconductor industry for depositing silicon layers (amorphous, micro-crystalline or polymorphous). These layers have applications in flat panel displays, sensors, and solar cells for instance. The inclusion of nano-crystallites in the amorphous

Jerome Alphonse Robert Remy

2005-01-01

335

Fusion Plasma Theory project summaries  

SciTech Connect

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 US 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 US Fusion Energy Program.

Not Available

1993-10-01

336

Inertial currents in isotropic plasma  

NASA Technical Reports Server (NTRS)

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.

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

1994-01-01

337

Inertial Currents in Isotropic Plasma  

NASA Technical Reports Server (NTRS)

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 plasma, 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, MED plasma. Solutions are developed by taking the MHD limit of 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.

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

1993-01-01

338

Inertial currents in isotropic plasma  

NASA Technical Reports Server (NTRS)

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 plasma, 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, magnetohyrodynamic (MHD) plasma. Solutions are developed by taking the MHD limit of 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.

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

1994-01-01

339

Plastic Deformations in Complex Plasmas  

SciTech Connect

Complex plasmas are macroscopic model systems of real solids and liquids, used to study underdamped dynamics and wave phenomena. Plastic deformations of complex plasma crystals under slow uniaxial compression have been studied experimentally and numerically. It is shown that the lattice becomes locally sheared and that this strain is relaxed by shear slips resulting in global uniform compression and heat generation. Shear slips generate pairs of dislocations which move in opposite directions at subsonic speeds.

Durniak, C.; Samsonov, D. [Department of Electrical Engineering and Electronics, University of Liverpool, Liverpool, L69 3GJ (United Kingdom)

2011-04-29

340

Plasma biomarkers of mouse aging  

Microsoft Academic Search

Normal aging is accompanied by a series of physiological changes such as gray hair, cataracts, reduced immunity, and increased\\u000a susceptibility to disease. To identify novel biomarkers of normal aging, we analyzed plasma proteins of male mice longitudinally\\u000a from 2 to 19 months of age. Plasma proteins were analyzed by two-dimensional gel electrophoresis and identified using mass\\u000a spectrometry (MS), MS\\/MS and liquid

Juan Ding; John J. Kopchick

341

Plasma treatment for fluxless soldering  

Microsoft Academic Search

Plasma treatment of printed circuit boards (PCB) with solid solder deposits (SSD) makes it possible to eliminate the application of conventional flux in reflow soldering process. This work deals with the dependence of surface modification of eutectic SnPb solder materials on gas pressure and gas flowrate of the CF4\\/air (10:1) gas mixture in the reactor. After plasma treatment, both metal

R. Deltschew; D. Hirsch; H. Neumann; T. Herzog; K. J. Wolter; M. Nowottnick; K. Wittke

2001-01-01

342

Cholecystokinin Elevates Mouse Plasma Lipids  

PubMed Central

Cholecystokinin (CCK) is a peptide hormone that induces bile release into the intestinal lumen which in turn aids in fat digestion and absorption in the intestine. While excretion of bile acids and cholesterol into the feces eliminates cholesterol from the body, this report examined the effect of CCK on increasing plasma cholesterol and triglycerides in mice. Our data demonstrated that intravenous injection of [Thr28, Nle31]-CCK at a dose of 50 ng/kg significantly increased plasma triglyceride and cholesterol levels by 22 and 31%, respectively, in fasting low-density lipoprotein receptor knockout (LDLR?/?) mice. The same dose of [Thr28, Nle31]-CCK induced 6 and 13% increases in plasma triglyceride and cholesterol, respectively, in wild-type mice. However, these particular before and after CCK treatment values did not achieve statistical significance. Oral feeding of olive oil further elevated plasma triglycerides, but did not alter plasma cholesterol levels in CCK-treated mice. The increased plasma cholesterol in CCK-treated mice was distributed in very-low, low and high density lipoproteins (VLDL, LDL and HDL) with less of an increase in HDL. Correspondingly, the plasma apolipoprotein (apo) B48, B100, apoE and apoAI levels were significantly higher in the CCK-treated mice than in untreated control mice. Ligation of the bile duct, blocking CCK receptors with proglumide or inhibition of Niemann-Pick C1 Like 1 transporter with ezetimibe reduced the hypercholesterolemic effect of [Thr28, Nle31]-CCK in LDLR?/? mice. These findings suggest that CCK-increased plasma cholesterol and triglycerides as a result of the reabsorption of biliary lipids from the intestine. PMID:23300532

Zhou, Lichun; Yang, Hong; Lin, Xinghua; Okoro, Emmanuel U.; Guo, Zhongmao

2012-01-01

343

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

2012-11-19

344

Anomalous Wakefields in Ultra-Narrow Plasmas  

NASA Astrophysics Data System (ADS)

The properties of relativistic non-linear plasma wakes excited by lasers or particle beams in an ultra-narrow plasma (radius less than the plasma skin depth and the displacement amplitude of plasma electrons in the wake) are described. The restoring force on the oscillating electrons is reduced compared to oscillations in a homogeneous plasma resulting in a wave frequency that can be several times smaller than that of the usual wake at the plasma frequency. The circumstance described here arises commonly in current laser wakefield experiments with tightly focused lasers that self-ionize a gas in the low plasma density or resonant laser wakefield regime.

Tarik, K.; Katsouleas, T.; Muggli, P.; Mori, W. B.; Gordon, D.

2001-10-01

345

Characterisation of plasma in a rail gun  

NASA Technical Reports Server (NTRS)

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.

Ray, P. K.

1986-01-01

346

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

347

Experimental investigations of ring-shaped plasma bullets emitted by a pulsed plasma jet  

Microsoft Academic Search

Non-thermal atmospheric pressure plasma jets have recently been playing an increasingly important role in plasma processing. These devices are able to provide plasma plumes\\/jets in ambient air and not confined by electrodes. In this paper we report experimental investigations on the characteristics of the plasma jet emitted by a pulsed plasma source, the \\

E. Karakas; A. Begum; M. Koklu; J. Jarrige; M. Laroussi

2009-01-01

348

Laser-Plasma Acceleration of Electrons and Plasma Diagnostics at High Laser Fields  

E-print Network

Laser-Plasma Acceleration of Electrons and Plasma Diagnostics at High Laser Fields Mike Downer: Laser-plasma acceleration is now entering an era of petawatt lasers, tenuous plasmas and multi.5395) Plasma diagnostics 1. Introduction 30 years ago, Tajima and Dawson proposed the idea of accelerating

Shvets, Gennady

349

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

NASA Technical Reports Server (NTRS)

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.

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

1998-01-01

350

High density large area hydrogen plasma by hollow cathode plasma array  

Microsoft Academic Search

Hydrogen plasma becomes an alternative to the conventional oxygen plasma in stripping photoresist in the next generation semiconductor processing because the conventional oxygen plasma is known to degrade ultralow dielectric constant films by depleting carbons from the films. An array of hollow cathode plasma is designed to have uniform and high density hydrogen plasma. From many combinations of cavity size

Jeonghee Cho; Jack Yang; Se-Geun Park

2010-01-01

351

Experiment of THz transmission through plasma  

NASA Astrophysics Data System (ADS)

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.

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

2014-12-01

352

Electric field divertor plasma pump  

DOEpatents

An electric field plasma pump includes a toroidal ring bias electrode positioned near the divertor strike point of a poloidal divertor of a tokamak, or similar plasma-confining apparatus. For optimum plasma pumping, the separatrix of the poloidal divertor contacts the ring electrode, which then also acts as a divertor plate. A plenum or other duct near the electrode includes an entrance aperture open to receive electrically-driven plasma. The electrode is insulated laterally with insulators, one of which is positioned opposite the electrode at the entrance aperture. An electric field E is established between the ring electrode and a vacuum vessel wall, 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. 11 figs.

Schaffer, M.J.

1994-10-04

353

Electric field divertor plasma pump  

DOEpatents

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.

Schaffer, Michael J. (San Diego, CA)

1994-01-01

354

A Short Introduction to Plasma Physics  

E-print Network

This chapter contains a short discussion of some fundamental plasma phenomena. In section 2 we introduce key plasma properties like quasi-neutrality, shielding, particle transport processes and sheath formation. In section 3 we describe the simplest plasma models: collective phenomena (drifts) deduced from single-particle trajectories and fundamentals of plasma fluid dynamics. The last section discusses wave phenomena in homogeneous, unbounded, cold plasma.

Wiesemann, K

2013-01-01

355

Megawatt Electromagnetic Plasma Propulsion  

NASA Technical Reports Server (NTRS)

The NASA Glenn Research Center program in megawatt level electric propulsion is centered on electromagnetic acceleration of quasi-neutral plasmas. Specific concepts currently being examined are the Magnetoplasmadynamic (MPD) thruster and the Pulsed Inductive Thruster (PIT). In the case of the MPD thruster, a multifaceted approach of experiments, computational modeling, and systems-level models of self field MPD thrusters is underway. The MPD thruster experimental research consists of a 1-10 MWe, 2 ms pulse-forming-network, a vacuum chamber with two 32 diffusion pumps, and voltage, current, mass flow rate, and thrust stand diagnostics. Current focus is on obtaining repeatable thrust measurements of a Princeton Benchmark type self field thruster operating at 0.5-1 gls of argon. Operation with hydrogen is the ultimate goal to realize the increased efficiency anticipated using the lighter gas. Computational modeling is done using the MACH2 MHD code, which can include real gas effects for propellants of interest to MPD operation. The MACH2 code has been benchmarked against other MPD thruster data, and has been used to create a point design for a 3000 second specific impulse (Isp) MPD thruster. This design is awaiting testing in the experimental facility. For the PIT, a computational investigation using MACH2 has been initiated, with experiments awaiting further funding. Although the calculated results have been found to be sensitive to the initial ionization assumptions, recent results have agreed well with experimental data. Finally, a systems level self-field MPD thruster model has been developed that allows for a mission planner or system designer to input Isp and power level into the model equations and obtain values for efficiency, mass flow rate, and input current and voltage. This model emphasizes algebraic simplicity to allow its incorporation into larger trajectory or system optimization codes. The systems level approach will be extended to the pulsed inductive thruster and other electrodeless thrusters at a future date.

Gilland, James; Lapointe, Michael; Mikellides, Pavlos

2003-01-01

356

Amplitude modulation of electron plasma waves in a quantum plasma  

SciTech Connect

Using the one dimensional quantum hydrodynamic model for a two-component electron-ion dense quantum plasma the linear and nonlinear properties of electron plasma waves are studied including ion motion. By using the standard method of multiple scales perturbation technique a nonlinear Schroedinger equation containing quantum effects is derived. From this equation it is shown that with immobile ions an electron plasma wave becomes modulationally unstable in two distinct regions of the wavenumber. Numerical calculation shows that the stability domain of the wavevector shrinks with the increase in quantum diffraction effect. It is also found that the growth rate of instability in the high wavenumber region increases with the increase in quantum effect. Ion motion is found to have significant effect in changing the stability/instability domains of the wavenumber in the low k-region.

Ghosh, Basudev; Chandra, Swarniv [Department of Physics, Jadavpur University, Kolkata 700032 (India); Paul, S. N. [Swami Vivekananda Institute of Science and Technology, Dakshin Gobindapur, P.S.-Sonarpur, Kolkata 700145 (India)

2011-01-15

357

Portable nanosecond pulsed air plasma jet  

SciTech Connect

Low-temperature atmospheric pressure plasmas are of great importance in many emerging biomedical and materials processing applications. The redundancy of a vacuum system opens the gateway for highly portable plasma systems, for which air ideally becomes the plasma-forming gas and remote plasma processing is preferred to ensure electrical safety. Typically, the gas temperature observed in air plasma greatly exceeds that suitable for the processing of thermally liable materials; a large plasma-sample distance offers a potential solution but suffers from a diluted downstream plasma chemistry. This Letter reports a highly portable air plasma jet system which delivers enhanced downstream chemistry without compromising the low temperature nature of the discharge, thus forming the basis of a powerful tool for emerging mobile plasma applications.

Walsh, J. L. [Department of Electrical Engineering and Electronics, University of Liverpool, Liverpool, Merseyside L69 3GJ (United Kingdom); Kong, M. G. [Department of Electronic and Electrical Engineering, Loughborough University, Loughborough, Leicestershire LE11 3TU (United Kingdom)

2011-08-22

358

Resonant laser plasma interactions and electron acceleration  

NASA Astrophysics Data System (ADS)

The interaction between intense laser radiation and a plasma is often dominated by the generation of large amplitude plasma waves. These plasma waves can drastically affect both the plasma particles of which they are composed and the laser radiation by which they are driven. This dissertation addresses two facets of these processes. In part I, the acceleration of electrons by highly nonlinear plasma waves is addressed. It is shown experimentally that energy gains exceeding the dephasing limit of linear theory are possible. In part II, the recent theory of electromagnetically induced transparency in a plasma is examined. It is found that the requirements of causality do not allow for the transmission of electromagnetic radiation through an overdense plasma as conceived in the original theory. However, it is possible for radiation below the cutoff frequency to be generated by a plasma. Also, a Raman-type instability is found to afflict electromagnetic waves in a plasma even when the density exceeds quarter-critical.

Gordon, Daniel Francis

1999-10-01

359

Micro-column plasma emission liquid chromatograph  

DOEpatents

In a direct current plasma emission spectrometer for use in combination with a micro-column liquid chromatograph, an improved plasma source unit. The plasma source unit includes a quartz capillary tube having an inlet means, outlet off gas means and a pair of spaced electrodes defining a plasma region in the tube. The inlet means is connected to and adapted to receive eluant of the liquid chromatograph along with a stream of plasma-forming gas. There is an opening through the wall of the capillary tube penetrating into the plasma region. A soft glass capillary light pipe is disposed at the opening, is connected to the spectrometer, and is adapted to transmit light passing from the plasma region to the spectrometer. There is also a source of electromotive force connected to the electrodes sufficient to initiate and sustain a plasma in the plasma region of the tube.

Gay, Don D. (Aiken, SC)

1984-01-01

360

Magnetized Plasma Expansion and its Interaction with a Plasma Stream  

NASA Technical Reports Server (NTRS)

Expansion of magnetized plasma in the magnetic field of a solenoid is studied by means of simulations using a 3-dimensional hybrid code. The plasma expands against a high- density and slow plasma stream (PS). The expansion causes inflation of the magnetic field; near the solenoid the magnetic field variation with increasing distance (r) remains as B(alpha)r(sup -3), but at farther distances B(alpha)r(sup -p), where the exponent p is found in the range 0.5 approx. less than p approx. less than 1.2 forming a plateau in the magnetic field distribution B(r). At the start of injection of plasma from the ends of the solenoid, the PS interacts with the solenoid magnetic field and creates a bow shock at a distance where the Larmor radius (r(sub il)) of the PS ions in the solenoid magnetic field nearly equals the scale length (L) of B(r), that is, r(sub il) approx. L = (B(sup -1)dB L /dr)(sup -1). As the injected plasma accumulates in the solenoid magnetic field, it expands inflating the magnetic field and the bow shock moves outward. The speed of the expansion front and the shock progressively decreases and eventually a stand-off occurs when the PS dynamic pressure is eventually balanced by the magnetic and kinetic pressures of the expanding plasma and the inflating magnetic field. The inflating field shows wave-like behavior, with considerable structures in the field and current distributions.

Singh, Nagendra; Saha, S.; Craven, P. D.; Gallagher, D.; Jones, J.

2003-01-01

361

Immunoradiometric assay of plasma lactoferrin.  

PubMed

The concentration of lactoferrin, a non-heme iron binding glycoprotein, was determined in more than 1500 EDTA plasma samples by a 2-site solid phase immunoradiometric assay to assess the significance of lactoferrin in plasma and to investigate applications for this assay. The use of commercially available antibody and antigen and a relatively short assay time make this assay more suitable for use in routine clinical laboratories than previous methods. A normal range of 250-750 micrograms/l was established. There was a correlation between plasma lactoferrin concentration and the circulating blood neutrophil count in most patients except those with splenomegaly, post-splenectomy and undergoing intensive chemotherapy. Patients with gross splenomegaly usually had an increased and post-splenectomy patients a decreased lactoferrin/neutrophil ratio indicating a respective increase and decrease in the marginated pool. In patients with acute leukemia after chemotherapy or transplantation plasma lactoferrin levels increased 1 to 5 d before blood neutrophil counts rose. As plasma lactoferrin seems to be derived from neutrophils, its concentration is probably related to the size of the total blood granulocyte pool. Calculation of the lactoferrin/neutrophil ratio demonstrated variations in the size of the bone marrow reserve and the marginated neutrophil pool. PMID:6856340

Brown, R D; Rickard, K A; Kronenberg, H

1983-01-01

362

The plasma environment of Uranus  

NASA Technical Reports Server (NTRS)

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.

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

1991-01-01

363

[Plasma properties research: Task 3  

SciTech Connect

The principal research activities of the Magneto-Fluid Dynamics Division relate to magnetic fusion plasma physics. In addition, there is a modest amount of work in closely related areas, including space plasma physics, fluid dynamics, and dynamical systems. Members of the Magneto-Fluid Dynamics Division maintain close contacts with fusion researchers in the US and abroad. Some of the work of the Division is clearly directed towards ITER and TPX, while other problems relate to the broader development of fusion plasma physics and to the support of other issues arising in the many experimental programs. Topics of some note in the last year that are discussed in this report are: Application of sophisticated statistical techniques to tokamak data reduction, including time series analysis of TFTR fluctuation data and spline analysis of profile data. Continuing development of edge plasma and divertor modelling, including initial ergodic divertor studies. Analysis of energetic fusion products losses from TFTR plasmas. Examination of anomalous transport in dynamical systems induced by chaotic-like Hamiltonian motion. Numerical simulation of the development of singular MHD equilibria. Exploration of the validity of moment expansions of kinetic equations for weakly collisional systems. Studies of RF- and ripple-induced helium ash removal. Ballooning mode studies in fluids and rotating stars. Studies in dynamical systems, including explosive instabilities, development of chaos, and motion of collisionless particles in a domain with overlapping islands.

Not Available

1992-01-01

364

[Plasma properties research: Task 3  

SciTech Connect

The principal research activities of the Magneto-Fluid Dynamics Division relate to magnetic fusion plasma physics. In addition, there is a modest amount of work in closely related areas, including space plasma physics, fluid dynamics, and dynamical systems. Members of the Magneto-Fluid Dynamics Division maintain close contacts with fusion researchers in the US and abroad. Some of the work of the Division is clearly directed towards ITER and TPX, while other problems relate to the broader development of fusion plasma physics and to the support of other issues arising in the many experimental programs. Topics of some note in the last year that are discussed in this report are: Application of sophisticated statistical techniques to tokamak data reduction, including time series analysis of TFTR fluctuation data and spline analysis of profile data. Continuing development of edge plasma and divertor modelling, including initial ergodic divertor studies. Analysis of energetic fusion products losses from TFTR plasmas. Examination of anomalous transport in dynamical systems induced by chaotic-like Hamiltonian motion. Numerical simulation of the development of singular MHD equilibria. Exploration of the validity of moment expansions of kinetic equations for weakly collisional systems. Studies of RF- and ripple-induced helium ash removal. Ballooning mode studies in fluids and rotating stars. Studies in dynamical systems, including explosive instabilities, development of chaos, and motion of collisionless particles in a domain with overlapping islands.

Not Available

1992-12-31

365

EDITORIAL: Focus on Plasma Medicine  

NASA Astrophysics Data System (ADS)

'Plasma Healthcare' is an emerging interdisciplinary research topic of rapidly growing importance, exploring considerable opportunities at the interface of plasma physics, chemistry and engineering with life sciences. Some of the scientific discoveries reported so far have already demonstrated clear benefits for healthcare in areas of medicine, food safety, environmental hygiene, and cosmetics. Examples include ongoing studies of prion inactivation, chronic wound treatment and plasma-mediated cancer therapy. Current research ranges from basic physical processes, plasma chemical design, to the interaction of plasmas with (i) eukaryotic (mammalian) cells; (ii) prokaryotic (bacteria) cells, viruses, spores and fungi; (iii) DNA, lipids, proteins and cell membranes; and (iv) living human, animal and plant tissues in the presence of biofluids. Of diverse interests in this new field is the need for hospital disinfection, in particular with respect to the alarming increase in bacterial resistance to antibiotics, the concomitant needs in private practices, nursing homes etc, the applications in personal hygiene—and the enticing possibility to 'design' plasmas as possible pharmaceutical products, employing ionic as well as molecular agents for medical treatment. The 'delivery' of the reactive plasma agents occurs at the gaseous level, which means that there is no need for a carrier medium and access to the treatment surface is optimal. This focus issue provides a close look at the current state of the art in Plasma Medicine with a number of forefront research articles as well as an introductory review. Focus on Plasma Medicine Contents Application of epifluorescence scanning for monitoring the efficacy of protein removal by RF gas-plasma decontamination Helen C Baxter, Patricia R Richardson, Gaynor A Campbell, Valeri I Kovalev, Robert Maier, James S Barton, Anita C Jones, Greg DeLarge, Mark Casey and Robert L Baxter Inactivation factors of spore-forming bacteria using low-pressure microwave plasmas in an N2 and O2 gas mixture M K Singh, A Ogino and M Nagatsu Degradation of adhesion molecules of G361 melanoma cells by a non-thermal atmospheric pressure microplasma H J Lee, C H Shon, Y S Kim, S Kim, G C Kim and M G Kong The acidification of lipid film surfaces by non-thermal DBD at atmospheric pressure in air A Helmke, D Hoffmeister, N Mertens, S Emmert, J Schuette and W Vioel Reduction and degradation of amyloid aggregates by a pulsed radio-frequency cold atmospheric plasma jet D L Bayliss, J L Walsh, G Shama, F Iza and M G Kong The effect of low-temperature plasma on bacteria as observed by repeated AFM imaging René Pompl, Ferdinand Jamitzky, Tetsuji Shimizu, Bernd Steffes, Wolfram Bunk, Hans-Ulrich Schmidt, Matthias Georgi, Katrin Ramrath, Wilhelm Stolz, Robert W Stark, Takuya Urayama, Shuitsu Fujii and Gregor Eugen Morfill Removal and sterilization of biofilms and planktonic bacteria by microwave-induced argon plasma at atmospheric pressure Mi Hee Lee, Bong Joo Park, Soo Chang Jin, Dohyun Kim, Inho Han, Jungsung Kim, Soon O Hyun, Kie-Hyung Chung and Jong-Chul Park Cell permeabilization using a non-thermal plasma M Leduc, D Guay, R L Leask and S Coulombe Physical and biological mechanisms of direct plasma interaction with living tissue Danil Dobrynin, Gregory Fridman, Gary Friedman and Alexander Fridman Nosocomial infections-a new approach towards preventive medicine using plasmas G E Morfill, T Shimizu, B Steffes and H-U Schmidt Generation and transport mechanisms of chemical species by a post-discharge flow for inactivation of bacteria Takehiko Sato, Shiroh Ochiai and Takuya Urayama Low pressure plasma discharges for the sterilization and decontamination of surfaces F Rossi, O Kylián, H Rauscher, M Hasiwa and D Gilliland Contribution of a portable air plasma torch to rapid blood coagulation as a method of preventing bleeding S P Kuo, O Tarasenko, J Chang, S Popovic, C Y Chen, H W Fan, A Scott, M Lahiani, P Alusta, J D Drake and M Nikolic A two-dimensional cold atmospheric plasma jet array for uniform treatment of large-area

Morfill, G. E.; Kong, M. G.; Zimmermann, J. L.

2009-11-01

366

Whistleron gas in magnetized plasmas  

SciTech Connect

The nonlinear dynamics of whistler waves in magnetized plasmas is studied. Since the plasmas and beam-plasma systems considered here are assumed to be weakly collisional, the point of reference for the analysis performed in the present paper is the system of hydrodynamic and field equations. The renormalization group method is applied to obtain dynamical equations for the slowly varying amplitudes of whistler waves. Further, it has been shown that the amplitudes of eigenmodes satisfy an infinite system of coupled nonlinear Schroedinger equations. In this sense, the whistler eigenmodes form a sort of a gas of interacting quasiparticles, while the slowly varying amplitudes can be considered as dynamical variables heralding the relevant information about the system. An important feature of the approach is that whistler waves do not perturb the initial uniform density of plasma electrons. The plasma response to the induced whistler waves consists in velocity redistribution which follows exactly the behavior of the whistlers. In addition, selection rules governing the nonlinear mode coupling have been derived, which represent another interesting peculiarity of the description presented here.

De Martino, Salvatore; Falanga, Mariarosaria; Tzenov, Stephan I. [Dipartimento di Fisica E.R. Caianiello, Universita degli Studi di Salerno, Via S. Allende, I-84081 Baronissi (Saudi Arabia) (Italy) and INFN Sezione di Napoli, Gruppo Collegato di Salerno, Via S. Allende, I-84081 Baronissi (SA) (Italy)

2005-07-15

367

Where is Coronal Plasma Heated?  

NASA Astrophysics Data System (ADS)

The coupling between the chromosphere and corona is a question of great current interest. It has long been understood that coronal mass originates in the chromosphere and that the energy which powers the corona flows up through the chromosphere. However, the details of how this happens are now being questioned. In the traditional view, “mechanical” energy flows into the corona in the form of waves or gradually increasing magnetic stresses. The waves and stresses dissipate and heat the plasma. The resulting downward thermal conduction flux causes material to evaporate from the chromosphere and fill the corona. If the heating is steady, an equilibrium is established whereby radiation and thermal conduction balance the energy input. If the heating is impulsive (a nanoflare), the evaporated plasma cools and drains, only to reappear during the next event. In either case, the heating occurs in the corona. A new idea is that the heating occurs instead in the chromosphere. Cold plasma is directly heated to coronal temperatures and then flows upward due to expansion and perhaps also an ejection process. The hot tips of type II spicules are one example, though spicules need not be involved. I will discuss these two fundamentally different scenarios and the observational predictions that they make. A comparison with actual observations leads to the conclusion that only a small fraction of the hot plasma in the corona comes from chromospheric heating. Most coronal plasma is a consequence of heating that occurs in the corona itself.

Klimchuk, James A.; Bradshaw, S.; Patsourakos, S.; Tripathi, D.

2013-07-01

368

Plasma Processing of Advanced Materials  

SciTech Connect

Plasma Processing of Advanced Materials The project had the overall objective of improving our understanding of the influences of process parameters on the properties of advanced superhard materials. The focus was on high rate deposition processes using thermal plasmas and atmospheric pressure glow discharges, and the emphasis on superhard materials was chosen because of the potential impact of such materials on industrial energy use and on the environment. In addition, the development of suitable diagnostic techniques was pursued. The project was divided into four tasks: (1) Deposition of superhard boron containing films using a supersonic plasma jet reactor (SPJR), and the characterization of the deposition process. (2) Deposition of superhard nanocomposite films in the silicon-nitrogen-carbon system using the triple torch plasma reactor (TTPR), and the characterization of the deposition process. (3) Deposition of films consisting of carbon nanotubes using an atmospheric pressure glow discharge reactor. (4) Adapting the Thomson scattering method for characterization of atmospheric pressure non-uniform plasmas with steep spatial gradients and temporal fluctuations. This report summarizes the results.

Heberlein, Joachim, V.R.; Pfender, Emil; Kortshagen, Uwe

2005-02-28

369

Recent Advances in Plasma Acceleration  

SciTech Connect

The costs and the time scales of colliders intended to reach the energy frontier are such that it is important to explore new methods of accelerating particles to high energies. Plasma-based accelerators are particularly attractive because they are capable of producing accelerating fields that are orders of magnitude larger than those used in conventional colliders. In these accelerators a drive beam, either laser or particle, produces a plasma wave (wakefield) that accelerates charged particles. The ultimate utility of plasma accelerators will depend on sustaining ultra-high accelerating fields over a substantial length to achieve a significant energy gain. More than 42 GeV energy gain was achieved in an 85 cm long plasma wakefield accelerator driven by a 42 GeV electron drive beam in the Final Focus Test Beam (FFTB) Facility at SLAC. Most of the beam electrons lose energy to the plasma wave, but some electrons in the back of the same beam pulse are accelerated with a field of {approx}52 GV/m. This effectively doubles their energy, producing the energy gain of the 3 km long SLAC accelerator in less than a meter for a small fraction of the electrons in the injected bunch. Prospects for a drive-witness bunch configuration and high-gradient positron acceleration experiments planned for the SABER facility will be discussed.

Hogan, Mark

2007-03-19

370

Photoaffinity labeling of plasma proteins.  

PubMed

Photoaffinity labeling is a powerful technique for identifying a target protein. A high degree of labeling specificity can be achieved with this method in comparison to chemical labeling. Human serum albumin (HSA) and ?1-acid glycoprotein (AGP) are two plasma proteins that bind a variety of endogenous and exogenous substances. The ligand binding mechanism of these two proteins is complex. Fatty acids, which are known to be transported in plasma by HSA, cause conformational changes and participate in allosteric ligand binding to HSA. HSA undergoes an N-B transition, a conformational change at alkaline pH, that has been reported to result in increased ligand binding. Attempts have been made to investigate the impact of fatty acids and the N-B transition on ligand binding in HSA using ketoprofen and flunitrazepam as photolabeling agents. Meanwhile, plasma AGP is a mixture of genetic variants of the protein. The photolabeling of AGP with flunitrazepam has been utilized to shed light on the topology of the protein ligand binding site. Furthermore, a review of photoaffinity labeling performed on other major plasma proteins will also be discussed. Using a photoreactive natural ligand as a photolabeling agent to identify target protein in the plasma would reduce non-specific labeling. PMID:24217326

Chuang, Victor Tuan Giam; Otagiri, Masaki

2013-01-01

371

Theoretical investigations of plasma processes  

NASA Technical Reports Server (NTRS)

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.

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

1976-01-01

372

Stationary Plasma Thruster Plume Emissions  

NASA Technical Reports Server (NTRS)

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.

Manzella, David H.

1994-01-01

373

MHD plasma acceleration in plasma thrusters: a variational approach  

NASA Astrophysics Data System (ADS)

A Hamiltonian formulation of the MHD plasma flow equations in terms of noncanonical variables is briefly discussed for the case of stationary axisymmetric configurations. This formulation makes it possible to cast these flow equations in a variational form with mixed (closed and/or open) boundary conditions. Within this framework the modelling of the acceleration channel of an applied-field Magneto-Plasma-Dynamic (MPD) thruster for space propulsion is discussed and shown to provide general relationships between the flow features and the thruster performance.

Andreussi, T.; Pegoraro, F.

2010-12-01

374

MHD plasma acceleration in plasma thrusters: a variational approach  

SciTech Connect

A Hamiltonian formulation of the MHD plasma flow equations in terms of noncanonical variables is briefly discussed for the case of stationary axisymmetric configurations. This formulation makes it possible to cast these flow equations in a variational form with mixed (closed and/or open) boundary conditions. Within this framework the modelling of the acceleration channel of an applied-field Magneto-Plasma-Dynamic (MPD) thruster for space propulsion is discussed and shown to provide general relationships between the flow features and the thruster performance.

Andreussi, T. [Alta SpA, Pisa (Italy); Pegoraro, F. [Physics Department, University of Pisa, Pisa (Italy)

2010-12-14

375

Electromagnetic plasma models for microwave plasma cavity reactors  

NASA Technical Reports Server (NTRS)

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.

Frasch, L.; Asmussen, J.

1984-01-01

376

Plasma vortices in the ionosphere and atmosphere  

NASA Astrophysics Data System (ADS)

Vortices observed in ionized clouds of thunderstorm fronts have the nature of plasma vortices. In this work, the need to account for the electrostatic instability of plasma in the origination, intensification, and decay of plasma vortices in the atmosphere is shown. Moisture condensation results in mass-energy transfer under the inhomogeneous spatial distribution of aerosols. If a phase volume of natural oscillations is transformed in the frequency-wave vector space in inhomogeneous plasma, the damping of plasma oscillations promotes an increase in the pressure gradients normal to the geomagnetic field. Excitation of the gradient instabilities is probable in atmospheric plasma formations.

Izhovkina, N. I.

2014-11-01

377

Ferroelectric plasma thruster for microspacecraft propulsion  

NASA Astrophysics Data System (ADS)

This paper presents a technology in microthruster design: the ferroelectric plasma thruster (FEPT). The FEPT utilizes an applied rf electric field to create plasma on the surface of a ferroelectric dielectric. Acceleration of ions from this plasma provides thrust. Advantages of the FEPT include emission of both electrons and ions leading to self-neutralization, creation of plasma, and acceleration of ions with a single power supply, and application of thrust in a short amount of time. We present the concept of the thruster, operational physics, as well as experimental results demonstrating plasma creation and ion acceleration. These results along with plasma spectroscopy allow us to calculate thruster parameters.

Kemp, Mark A.; Kovaleski, Scott D.

2006-12-01

378

Two stream instabilities in degenerate quantum plasmas  

E-print Network

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.

S. Son

2013-10-18

379

Double layer formation. [in plasma  

NASA Technical Reports Server (NTRS)

An investigation is conducted of the plasma processes which occur during the formation of a double layer in response to an applied initial electric field, when triggered by a current in the plasma. The important feature of the formation process was the creation of an ion-rich plasma-density cavity. The positive space charge of the cavity was shielded by induction of a negative space charge on the low potential side of the cavity, giving rise to the formation of a fully developed double layer. The shielding was complete only when the electron current from the low potential side exceeded the electron thermal current. It was found that during the formation of double layers counterstreaming electrons are generated. Moreover, transient double layers with reverse polarity also occur during this phase. Thus, the recurring formation of double layers can give rise to flickering double layers.

Singh, N.

1982-01-01

380

Nonlinear dynamics and plasma transport  

SciTech Connect

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.

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

1993-01-01

381

Constricted glow discharge plasma source  

DOEpatents

A constricted glow discharge chamber and method are disclosed. The polarity and geometry of the constricted glow discharge plasma source is set so that the contamination and energy of the ions discharged from the source are minimized. The several sources can be mounted in parallel and in series to provide a sustained ultra low source of ions in a plasma with contamination below practical detection limits. The source is suitable for applying films of nitrides such as gallium nitride and oxides such as tungsten oxide and for enriching other substances in material surfaces such as oxygen and water vapor, which are difficult process as plasma in any known devices and methods. The source can also be used to assist the deposition of films such as metal films by providing low-energy ions such as argon ions.

Anders, Andre (Albany, CA); Anders, Simone (Albany, CA); Dickinson, Michael (San Leandro, CA); Rubin, Michael (Berkeley, CA); Newman, Nathan (Winnetka, IL)

2000-01-01

382

Plasma Injection Experiment at MCX  

NASA Astrophysics Data System (ADS)

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.

Uzun-Kaymak, Ilker; Messer, S.

2008-11-01

383

Wakefield generation in magnetized plasmas  

SciTech Connect

We consider wakefield generation in plasmas by electromagnetic pulses propagating perpendicular to a strong magnetic field, in the regime where the electron cyclotron frequency is equal to or larger than the plasma frequency. Particle-in-cell simulations reveal that for moderate magnetic field strengths previous results are reproduced, and the wakefield wave number spectrum has a clear peak at the inverse skin depth. However, when the cyclotron frequency is significantly larger than the plasma frequency, the wakefield spectrum becomes broadband, and simultaneously the loss rate of the driving pulse is much enhanced. A set of equations for the scalar and vector potentials reproducing these results are derived, using only the assumption of a weakly nonlinear interaction.

Holkundkar, Amol; Brodin, Gert; Marklund, Mattias [Department of Physics, Umeaa University, SE-901 87 Umeaa (Sweden)

2011-09-15

384

Ferrite Loaded DBD Plasma Device  

NASA Astrophysics Data System (ADS)

An atmospheric pressure plasma jet device with dielectric barrier discharge was built using low cost 5C22 thyratron valve and ferrite transformer. The ferrite transformer increases the intensity about four times the primary pulse and lengthens the high voltage pulse, keeping the rise time of the thyratron pulse. Spectrometer measurement shows excited nitrogen molecular emissions of second positive system. The most intense nitrogen molecular line, 357.69 nm, was chosen to monitor the time dependence of the discharge. Synthetic temperature, using 380.49 nm line of N2 emission and SpecAir simulation, shows plasma gas temperature of 300 K. To corroborate this low temperature, the plasma jet is applied to human tongue with no harm or bad physical feeling.

Machida, M.

2015-02-01

385

Plasma Panel Based Radiation Detectors  

SciTech Connect

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.

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

386

Particle Acceleration in relativistic plasmas  

NASA Astrophysics Data System (ADS)

We review our recent results on particle acceleration in shocks [1], in reconnection [2] and via wave-particle interactions in microinstabilites [3]. After reviewing the fundamental issues in particle acceleration in the three classes of problems mentioned above, we focus specifically on the interactions of waves and particles during the evolution of plasma microinstabilites. We consider a new mechanism responsible for exceedingly strong acceleration events in relativistic plasmas. We conduct simulations of streaming plasmas (generated for example in astrophysical processes such as jets or in shocks) and consider the evolution of instabilities, comparing the classical and the relativistic evolution. The cause of the new processes is discussed in ration with the properties of the Minkowski space-time itself [3]. [1] G. Lapenta, J. King, JGR, to appear. [2] W. Wan, G. Lapenta, GRL, submitted [3] G. Lapenta et al, ApJ, to appear.

Lapenta, G.

2007-12-01

387

Particle transport in plasma reactors  

SciTech Connect

SEMATECH and the Department of Energy have established a Contamination Free Manufacturing Research Center (CFMRC) located at Sandia National Laboratories. One of the programs underway at the CFMRC is directed towards defect reduction in semiconductor process reactors by the application of computational modeling. The goal is to use fluid, thermal, plasma, and particle transport models to identify process conditions and tool designs that reduce the deposition rate of particles on wafers. The program is directed toward defect reduction in specific manufacturing tools, although some model development is undertaken when needed. The need to produce quantifiable improvements in tool defect performance requires the close cooperation among Sandia, universities, SEMATECH, SEMATECH member companies, and equipment manufacturers. Currently, both plasma (e.g., etch, PECVD) and nonplasma tools (e.g., LPCVD, rinse tanks) are being worked on under this program. In this paper the authors summarize their recent efforts to reduce particle deposition on wafers during plasma-based semiconductor manufacturing.

Rader, D.J.; Geller, A.S.; Choi, Seung J. [Sandia National Labs., Albuquerque, NM (United States); Kushner, M.J. [Illinois Univ., Urbana, IL (United States)

1995-01-01

388

Exotic affinities under Debye plasma  

SciTech Connect

Muonic affinities of the exotic system {pi}{sup +}{mu}{sup -} have been calculated variationally using a general three-body formalism. The system is found to be stable in the ground state under Coulomb coupling. The stability of this system under an external plasma environment has been analyzed using multiterm correlated basis sets of Hylleraas type. The effect of external plasma has been incorporated using the standard Debye screening model. The system tends toward gradual instability under the increased strength of the plasma, and the affinities have been found to decrease gradually and systematically. The effect of correlation on the exotic affinities has been analyzed in detail. The effect of angular correlation on exotic affinities is found to be around 40-80%.

Bhattacharyya, S.; Sil, A. N.; Mukherjee, T. K.; Mukherjee, P. K. [Kandi Raj College, Kandi, Murshidabad, West Bengal 742 137 (India); Department of Spectroscopy, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032 (India); Narula Institute of Technology, Agarpara, Kolkata 700 109 (India); Department of Spectroscopy, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032 (India)

2007-02-15

389

Plasma Wakefield Experiments at FACET  

SciTech Connect

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.

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

390

Plasma deposition of oxide cathodes  

NASA Astrophysics Data System (ADS)

Vacuum arc deposition is employed to create a barium and/or strontium plasma which is subsequently deposited/implanted onto a nickel cathode substrate. The primary motivation for this work is the critical need for a reliable, repeatable, long-lived thermionic cathode for the production of high power, microsecond duration microwave pulses; such cathodes may also have applicability for lower current density continuous wave devices. This novel approach to manufacturing an oxide cathode eliminates the binders that may subsequently (and unpredictably) poison cathode emission. Removal of the poisoning mechanisms has yielded oxide cathodes capable of emission densities in the 20 A/cm2 regime. Cathode lifetime and emission may be varied via the control over the deposition parameters such as coating thickness, implantation energy, and plasma stoichiometry. The deposition is performed by generating a cathodic arc discharge at the surface of a barium or barium-strontium alloy rod. The metal plasma thus created is then deposited on the substrate which can be negatively biased to encourage implantation during the deposition process. The deposition is performed with sufficient background oxygen present to oxidize the highly reactive metal coating. The plasma deposition is monitored via a rate thickness monitor, an optical emission spectrometer for plasma composition information, and an electrostatic Langmuir probe for the determination of the plasma density and temperature profile. Cathodes thus produced are analyzed by drawing pulsed current at a constant voltage for various values of decreasing cathode temperature in order to generate practical work function distributions which provide an indication of the quality and expected life time of the cathode. In support of analyzing these cathodes (as well as a variety of cathodes from other sources), a complete UHV cathode test and analysis system has been assembled which includes 3-D beam profiling, advanced temperature measurement, residual gas analysis, bulk cold work function measurement, and surface analysis with depth profiling.

Umstattd, R.; Pi, T.; Luhmann, N.; Scheitrum, G.; Caryotakis, G.; Miram, G.

1999-05-01

391

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

DOEpatents

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.

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

1994-01-01

392

Analysis of the plasma sweeper  

SciTech Connect

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.

Glanz, J.; Motley, R.W.

1982-09-01

393

Ballistic piston fissioning plasma experiment.  

NASA Technical Reports Server (NTRS)

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.

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

1971-01-01

394

Anodic plasma in Hall thrusters  

SciTech Connect

In this paper plasma dynamics and ionization of propellant gas are modeled within the anode holes used for gas injection of a Hall thruster. Under conditions of anode coating with dielectric material, the discharge current should close within these holes, which results in ionization and formation of plasma jets emanating from the openings. The model shows that gas ionization inside the anode holes is very significant. For instance, the electron density increases by two orders of magnitude under certain conditions. The potential drop in the anode region which includes the electrostatic sheath inside the hole and potential drop along the hole might be positive or negative, depending on the anode hole radius.

Keidar, Michael [Department of Mechanical and Aerospace Engineering, The George Washington University, Washington, DC 20052 (United States)

2008-03-01

395

Diagnostic enhancements for plasma processing  

SciTech Connect

This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). Funds obtained under this project were used to enhance the diagnostic capabilities of the plasma-processing program in the Physics Division at LANL and include successful development and implementation of in-situ Raman spectroscopy and infrared emission spectroscopy. These methods were used to detect the presence and nature of ground-state and electronically excited molecular oxygen formed in an atmospheric-pressure, nonthermal plasma source used for environmental, industrial and decontamination applications.

Selwyn, G.S.; Henins, I.

1998-12-31

396

Relativistic effects on plasma expansion  

NASA Astrophysics Data System (ADS)

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.

Benkhelifa, El-Amine; Djebli, Mourad

2014-07-01

397

Relativistic effects on plasma expansion  

SciTech Connect

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.

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

398

An introduction to quantum plasmas  

E-print Network

Shielding effects in non-degenerate and degenerate plasmas are compared. A detailed derivation of the Wigner-Poisson system is provided for electrostatic quantum plasmas where relativistic, spin and collisional effects are not essential. Later a detailed derivation of a quantum hydrodynamic model starting from the Wigner-Poisson system is shown. The route for this derivation considers the eikonal decomposition of the one-body wavefunctions of the quantum statistical mixture. The merits and limitations of the resulting quantum hydrodynamic model are discussed.

Fernando Haas

2012-06-05

399

Interactive Plasma Physics Education Experience  

NSDL National Science Digital Library

IPPEX (Internet Plasma Physics Education Experience) is a project developed to allow students and teachers to participate remotely in scientific research at the nation's largest fusion energy laboratory. It offers an introduction to the study of controlled fusion using the tokamak reactor, a fusion confinement device located at Princeton University. The web site includes simulations of plasma reactions and an interactive tutorial on the process of fusion, its potential as a sustainable energy source, and the challenges of harnessing its power. The data analysis exercises are appropriate for introductory physics learners.

Laboratory, Princeton P.

2003-10-10

400

Effect of background plasma nonlinearities on dissipation processes in plasmas  

NASA Astrophysics Data System (ADS)

The Coulomb collision effect on the bounce-resonance dissipation is considered for toroidal magnetized plasmas. The solution of the Vlasov equation with a simplified Fokker-Planck collision operator is presented. The parallel components of the dielectric tensor are obtained. A collisionless limit of wave dissipation is found.

Nekrasov, F. M.; Elfimov, A. G.; de Azevedo, C. A.; de Assis, A. S.

1999-01-01

401

Laser-Plasma Acceleration of Electrons and Plasma Diagnostics  

E-print Network

to miniaturize proton cancer therapy. Laser MeV protons Target H-rich film e $6 B $0.5 B $0.2 B Laser-plasma proton accelerators are poised. Special Topics - Accel. & Beams 10, 061301 (2007) "Generating multi-GeV electron bunches using single

Shvets, Gennady

402

LCDProjektorenPlasmaLCDProjektorenPlasmaLCDProjektoren NEC MultiSync  

E-print Network

Wide (16:10 Format) Office Monitore, die gro�e 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

Ott, Albrecht

403

The origins of the plasma in the distant plasma sheet  

Microsoft Academic Search

It is pointed out that ion mass spectrometers operating in the keV range have recently begun to provide a new class of information on magnetospheric processes. One of the principal motivations for the development of energetic ion mass spectrometers has been to investigate the origins of the hot plasma populations of the magnetosphere. Peterson et al. (1981) were able to

R. D. Sharp; W. Lennartsson; W. K. Peterson; E. G. Shelley

1982-01-01

404

TPSS plasma engineering studies: Profile effects and plasma power balance  

NASA Astrophysics Data System (ADS)

A computationally fast profile-averaged, steady-state plasma model has been developed to allow studies of radial effects in ignited and driven tokamak systems. This code was used to search for the smallest size tokamak consistent with power balance calculation.

Borowski, S. K.; Strickler, D. J.

405

Oxygen plasma harmonic stability in a RIE plasma tool  

NASA Astrophysics Data System (ADS)

We report the results of a study in which the detailed RF harmonic response of capacitively-coupled technological plasmas to the fundamental drive frequency of 13.56 MHz has been monitored. Using a dual-directional coupler (DDC) inserted at the 50 Ohm input port of the matching network to detect, in real time, the incident and reflected power in the travelling waves propagating along its through line, we have studied the behaviour of plasma-generated harmonics during etch processes. Two sets of experiments were performed: in the first, the output of the DDC sampling line was connected to a very high resolution digital spectrum analyser that allowed the frequencies and amplitudes of the plasma-generated harmonics to be monitored individually. The second experiment sampled the DDC output into a digital oscilloscope, from which the harmonic amplitude and phase relative to the incident fundamental were measured. The instrument has been used for the end-point detection of 1.8 micron thick Microposit S1818 photoresist etching on a 50 mm diameter silicon wafer using an oxygen plasma. Our results show that all three measurements harmonic amplitude, harmonic relative phase, and harmonic frequency yield valuable process-specific information. Selected harmonics exhibit a step-change in their amplitude and/or relative phase at etch end-points. However, although the harmonic frequencies also shift due to the changing complex impedance of the plasma loading the output of the RF generator, the frequency shift is a gradual one, moving asymptotically to a stable value as the process end-point is reached. We postulate that the two classes of measurement yield qualitatively different information.

Pagliarani, Amedeo; Kenyon, Anthony; Thornhill, Nina; Sirisena, Ehantha; Lee, Kevin; Law, Victor

2004-09-01

406

Observation of Collective Modes of Ultracold Plasmas  

NASA Astrophysics Data System (ADS)

Applying a radio-frequency electric field to an expanding ultracold neutral plasma leads to the observation of as many as six peaks in the emission of electrons from the plasma. These are identified as collective modes of the plasma and are in qualitative agreement with a model of Tonks-Dattner resonances, electron sound waves propagating in a finite-sized, inhomogeneous plasma. The existing theories that describe Tonks-Dattner resonances assume a fixed outer boundary condition, which is absent from our plasmas that expand freely into vacuum. In calculating the mode frequencies, we assume an outer boundary related to the size of the plasma. These modes are not predicted within cold plasma theory and require in inclusion of the electron pressure term, which is proportional to the electron temperature , in the fluid equations. Such modes may provide an accurate method to determine the time- dependent electron temperature, applicable over a large range in time and density of the expanding plasmas.

Zhang, Xianli; Fletcher, Robert; Rolston, Steven

2006-05-01

407

Initial measurements in the Fisk Plasma Source  

NASA Astrophysics Data System (ADS)

A new plasma source, the Fisk Plasma Source (FPS), has been developed at Fisk University. This plasma device will be used to study the physics of low temperature plasmas and plasma-materials interactions. The FPS device is a stainless steel 6-way cross vacuum vessel with a 10 inch inner diameter. Low temperature argon plasmas are generated using a DC glow discharge technique. Two selenoid electromagnets are wound directly on to the exterior of the vacuum vessel to produce magnetic fields of up to 200 Gauss. Langmuir probe measurements are used to determine spatial profiles of the plasma density and the electron temperature. We present experimental measurements of density and temperature profiles in the FPS device. We will also present the results of initial plasma-material interaction studies.

Wallace, Kent; Lampkin, Gregory; Thomas, Edward; Chen, Henry

1997-11-01

408

Plasma stability in a dipole magnetic field  

E-print Network

The MHD and kinetic stability of an axially symmetric plasma, confined by a poloidal magnetic field with closed lines, is considered. In such a system the stabilizing effects of plasma compression and magnetic field ...

Simakov, Andrei N., 1974-

2001-01-01

409

The plasma focus as a thruster  

E-print Network

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...

Hardy, Richard Lee

2005-02-17

410

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

411

A Plasma Lens for Magnetron Sputtering  

SciTech Connect

A plasma lens, consisting of a solenoid and potential-defining ring electrodes, has been placed between a magnetron and substrates to be coated. Photography reveals qualitative information on excitation, ionization, and the transport of plasma to the substrate.

Anders, Andre; Brown, Jeff

2010-11-30

412

A Survey of Plasmas and Their Applications  

NASA Technical Reports Server (NTRS)

Plasmas are everywhere and relevant to everyone. We bath in a sea of photons, quanta of electromagnetic radiation, whose sources (natural and artificial) are dominantly plasma-based (stars, fluorescent lights, arc lamps.. .). Plasma surface modification and materials processing contribute increasingly to a wide array of modern artifacts; e.g., tiny plasma discharge elements constitute the pixel arrays of plasma televisions and plasma processing provides roughly one-third of the steps to produce semiconductors, essential elements of our networking and computing infrastructure. Finally, plasmas are central to many cutting edge technologies with high potential (compact high-energy particle accelerators; plasma-enhanced waste processors; high tolerance surface preparation and multifuel preprocessors for transportation systems; fusion for energy production).

Eastman, Timothy E.; Grabbe, C. (Editor)

2006-01-01

413

Plasma igniter for internal-combustion engines  

NASA Technical Reports Server (NTRS)

Hot ionized gas (plasma) ignites air/fuel mixture in internal combustion engines more effectively than spark. Electromagnetic forces propel plasma into combustion zone. Combustion rate is not limited by flame-front speed.

Breshears, R. R.; Fitzgerald, D. J.

1978-01-01

414

Astrophysical / Solar system Plasmas : an introduction  

E-print Network

Astrophysical / Solar system Plasmas : an introduction Philippe Zarka LESIA, CNRS UMR 8109 ­ Observatoire de Paris, Meudon philippe.zarka@obspm.fr #12;· Plasma = 4th state of matter .B = 0 .E = /o �E = -B

Demoulin, Pascal

415

Pulse Plasma Surface Thermostrengthening of Machine Parts  

NASA Astrophysics Data System (ADS)

The paper presents a pulse plasma generator for surface hardening of parts. The given equations allow to calculate the parameters of the pulse plasma generator to ensure the specified quality indicators of the hardened zone.

Israfilov, I. H.; Galiakbarov, A. T.; Bashmakov, D. A.; Gabdrahmanov, A. T.; Samigullin, A. D.

2014-12-01

416

Magnetron cathodes in plasma electrode Pockels cells  

DOEpatents

Magnetron cathodes, which produce high current discharges, form greatly improved plasma electrodes on each side of an electro-optic crystal. The plasma electrode has a low pressure gas region on both sides of the crystal. When the gas is ionized, e.g., by a glow discharge in the low pressure gas, the plasma formed is a good conductor. The gas electrode acts as a highly uniform conducting electrode. Since the plasma is transparent to a high energy laser beam passing through the crystal, the plasma is transparent. A crystal exposed from two sides to such a plasma can be charged up uniformly to any desired voltage. A typical configuration utilizes helium at 50 millitorr operating pressure and 2 kA discharge current. The magnetron cathode produces a more uniform plasma and allows a reduced operating pressure which leads to lower plasma resistivity and a more uniform charge on the crystal. 5 figs.

Rhodes, M.A.

1995-04-25

417

Princeton Plasma Physics Laboratory NSTX Experimental Proposal  

E-print Network

Princeton Plasma Physics Laboratory NSTX Experimental Proposal Title: Vertical Stability Physics: Vertical Stability Physics and Performance Limits in Tokamaks with Highly Elongated Plasmas No. OP-XP-811 to get statistically sound data. 3. If time permits, we will repe

Princeton Plasma Physics Laboratory

418

Plasma therapy in foals and adult horses.  

PubMed

Although a range of plasma-based products (e.g., cryoprecipitate, albumin, platelet-rich plasma, individual coagulation factors) are available to human physicians, equine veterinarians are largely restricted to using whole blood, frozen plasma, and fresh frozen plasma for transfusions. The indications for frozen or fresh frozen plasma in human medicine are relatively limited, and there is little evidence supporting the efficacy of these products in many cases. Furthermore, many human physicians have concerns regarding disease transmission and anaphylactic reactions after administration of any plasma product. In equine medicine, plasma products have been used (1) to treat failure of passive transfer (FPT); sepsis; and coagulopathies; (2) as "antiendotoxin" agents; and (3) to provide colloidal support. The use of plasma should be carefully considered before administration because of potential (although rare) adverse reactions as well as expense. In addition, the benefits are uncertain in some equine patients. PMID:22012844

Tennent-Brown, Brent

2011-10-01

419

The study of helicon plasma source  

SciTech Connect

Helicon plasma source is known as efficient generator of uniform and high density plasma. A helicon plasma source was developed for investigation of plasma neutralization and plasma lens in the Institute of Modern Physics in China. In this paper, the characteristics of helicon plasma have been studied by using Langmuir four-probe and a high argon plasma density up to 3.9x10{sup 13} cm{sup -3} have been achieved with the Nagoya type III antenna at the conditions of the magnetic intensity of 200 G, working gas pressure of 2.8x10{sup -3} Pa, and rf power of 1200 W with a frequency of 27.12 MHz. In the experiment, the important phenomena have been found: for a given magnetic induction intensity, the plasma density became greater with the increase in rf power and tended to saturation, and the helicon mode appeared at the rf power between 200 and 400 W.

Miao Tingting; Shang Yong [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Zhao Hongwei; Liu Zhanwen; Sun Liangting; Zhang Xuezhen; Zhao Huanyu [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

2010-02-15

420

Observation of Collective Modes of Ultracold Plasmas  

NASA Astrophysics Data System (ADS)

Applying a radio-frequency electric field to an expanding ultracold neutral plasma leads to the observation of as many as six peaks in the emission of electrons from the plasma. These are identified as collective modes of the plasma and are in qualitative agreement with a model of Tonks-Dattner resonances, electron sound waves propagating in a finite-sized, inhomogeneous plasma. Such modes may provide an accurate method to determine the time-dependent electron temperature.

Fletcher, R. S.; Zhang, X. L.; Rolston, S. L.

2006-03-01

421

Observation of collective modes of ultracold plasmas.  

PubMed

Applying a radio-frequency electric field to an expanding ultracold neutral plasma leads to the observation of as many as six peaks in the emission of electrons from the plasma. These are identified as collective modes of the plasma and are in qualitative agreement with a model of Tonks-Dattner resonances, electron sound waves propagating in a finite-sized, inhomogeneous plasma. Such modes may provide an accurate method to determine the time-dependent electron temperature. PMID:16605743

Fletcher, R S; Zhang, X L; Rolston, S L

2006-03-17

422

Plasma treatment of aluminum for adhesive bonding  

Microsoft Academic Search

Plasma polymerized silicon-containing films were deposited onto aluminum coupons and used as primers for structural adhesive bonding. Hexamethyldisiloxane was polymerized within radio frequency (RF) and microwave (MW) plasmas to deposit coatings that were less than 1000 A thick. Substrate pre-treatments, carrier gas, excitation frequency, and plasma post-treatments were varied to produce films that performed well as primers. These plasma polymerized

Catherine Elizabeth Taylor

1997-01-01

423

Princeton University Plasma Physics Laboratory  

E-print Network

pgs. Plasmas Rewoldt, G. Preprint: January 1993 SEQUENTIAL LIST PPPL-2875 Ion Cyclotron and Spin.E., Synakowski, E.J., Taylor, G., Towner, H.H., Zarnstorff, M.C. PPPL-2881 Helium, Iron, and Electron Particle on TFTR and Synakowski, E.J. 17 pgs. Implications for Helium Ash in Future Fusion Devices Preprint: March

424

Princeton University Plasma Physics Laboratory  

E-print Network

pgs. Plasmas Rewoldt, G. Preprint: January 1993 SEQUENTIAL LIST PPPL­2875 Ion Cyclotron and Spin.E., Synakowski, E.J., Taylor, G., Towner, H.H., Zarnstorff, M.C. PPPL­2881 Helium, Iron, and Electron Particle on TFTR and Synakowski, E.J. 17 pgs. Implications for Helium Ash in Future Fusion Devices Preprint: March

425

Double layers in contactor plasmas  

NASA Technical Reports Server (NTRS)

The concept of using a hollow cathode to establish a low impedance contact between a spacecraft and the ambient plasma continues to gain in popularity, and is often then referred to as a plasma contactor. A growing number of studies indicate that large contact currents can be supported with small potential difference between the contactor and the ambient plasma. Results will be presented from a simple one-dimensional spherical model that obtains potentials from the solution of Poisson's equation, and particle densities from a turning point formalism that includes particle angular momentum. The neglect of collisions and magnetic field limits the realism. However, the results illustrate the effect of double layers that can form at the interface between contactor and ambient plasmas, when there is any voltage differential between the contactor and the ambient. The I-V characteristic of this model shows the usual space charge depends upon collection when the contactor flux is lower than some threshold; independence of I from variation in V when the flux is slightly greater than that threshold, and (numerical ?) instability for excessive flux suggesting the possibility of negative resistance. Even if a real I-V characteristic does not exhibit negative resistance, flat spots or high resistance regions may still be troublesome (or useful) to the total circuit.

Cooke, David L.

1990-01-01

426

Properties of plasma radiation diagnostics  

SciTech Connect

A number of diagnostics utilizing the radiation emitted from high-temperature plasmas have been developed at Los Alamos. Photoemissive x-ray diodes with photon energy bandpass filters provide time resolved rough spectral data from bout 6 eV to > 10 keV photon energy. Filtered silicon photodiodes can be used down to 1 eV and offer the advantages of nominally flat response and ability to operate in poor vacuum conditions. Both types of diodes will provide a rough time resolved spectrum and both are relatively inexpensive, reliable, and passive (i.e. no synchronization problems). For higher energy resolution bent crystal spectrographs are used in the x-ray region. With the addition of streak cameras or gated microchannel plates these systems provide data with high energy and high time resolution. To measure the total energy output a thin foil bolometer is used that measures the change in foil resistance as it is heated by the plasma radiation. Information on the physical location of the plasma is provided by a suite of visible framing cameras and x-ray pinhole cameras. By combining these diagnostics into a complementary set good diagnostic information can be guaranteed on any plasma experiment.

Idzorek, G.C.; Oona, H.

1996-06-01

427

Biological decontamination by nonthermal plasmas  

Microsoft Academic Search

Nonthermal gaseous discharges have been found to be effective agents for biological decontamination\\/sterilization. The ability to generate these discharges at atmospheric pressure makes the decontamination process practical and inexpensive. In addition, the fact that the plasmas generated by such discharges are cold makes their use suitable for applications where medium preservation is desired. To fully understand the biophysical and biochemical

Mounir Laroussi; Igor Alexeff; Weng L. Kang

2000-01-01

428

The Plasma Magnet John Slough  

E-print Network

power from the solar wind. ·The ultimate spacecraft speed powered by the plasma magnet MW of thrust power. The effective "thruster" efficiency can be greater than 1 ­ and as large the Solar Wind plications: ulti-MW thruster leveraged from multi-KW RF power agneto-braking in magnetosphere

Shepherd, Simon

429

Plasma Clouds in the Magnetosphere  

Microsoft Academic Search

Previous equatorial observations of the magnetospheric plasma [Gringauz, 1961; Frank, 1967 a, b, c, 1970; Vasyliunas, 19'6.8; Frank and Owens, 1970] have been made from spacecraft that made rapid but infrequent traversals of the region between 5 and 20 Rr or, as for the Vela spacecraft Bame et al., 1967], remained at great distances. The ATS I observations [Freeman and

S. E. DeForest; C. E. McIlwain

1971-01-01

430

Plasma sheet behavior during substorms  

SciTech Connect

Auroral or magnetic substorms are periods of enhanced auroral and geomagnetic activity lasting one to a few hours that signify increased dissipation of energy from the magnetosphere to the earth. Data acquired during the past decade from satellites in the near-earth sector of the magnetotail have suggested that during a substorm part of the plasma sheet is severed from earth by magnetic reconnection, forming a plasmoid, i.e., a body of plasma and closed magnetic loops, that flows out of the tail into the solar wind, thus returning plasma and energy that have earlier been accumulated from the solar wind. Very recently this picture has been dramatically confirmed by observations, with the ISEE 3 spacecraft in the magnetotail 220 R/sub E/ from earth, of plasmoids passing that location in clear delayed response to substorms. It now appears that plasmoid release is a fundamental process whereby the magnetosphere gives up excess stored energy and plasma, much like comets are seen to do, and that the phenomena of the substorm seen at earth are a by-product of that fundamental process.

Hones, E.W. Jr.

1983-01-01

431

Waves in Space Plasmas (WISP)  

NASA Technical Reports Server (NTRS)

Activities under this project have included participation in the Waves in Space Plasmas (WISP) program, a study of the data processing requirements for WISP, and theoretical studies of radio sounding, ducting, and magnetoionic theory. An analysis of radio sounding in the magnetosphere was prepared.

Calvert, Wynne

1994-01-01

432

Vacuum arc plasma mass separator  

NASA Astrophysics Data System (ADS)

The propagation of a metal plasma flow in a transport system with a curvilinear magnetic field was studied experimentally. The flow was generated by a pulsed vacuum arc discharge with a composite (W+Fe) cathode. The ion energy measurements at the transport system output showed that all ion components were accelerated up to equal energies per charge unit, about 150 eV and 320 eV in the outer and inner areas of the curved plasma flow, respectively. The spatial separation of the atoms of the cathode material was measured at the system output by x-ray fluorescence spectrometry. The ions of the lighter element (Fe) were concentrated in the inner part of the cathodic plasma flow deflected by the magnetic field while the distribution of the heavy element (W) was substantially shifted toward the outer area of the flow. The maximum mass separation efficiency reached 45, the effective value being 7.7. Such a system is promising for use in plasma technology for reprocessing spent nuclear fuel, namely for the separation of the heavy radioactive fission product from nuclear waste.

Paperny, V. L.; Krasov, V. I.; Lebedev, N. V.; Astrakchantsev, N. V.; Chernikch, A. A.

2015-02-01

433

Cold plasma decontamination of foods  

Technology Transfer Automated Retrieval System (TEKTRAN)

Cold plasma is a novel nonthermal food processing technology which uses energetic, reactive gases to inactivate contaminating microbes on meats, poultry and fruits and vegetables. This flexible sanitizing method uses electricity and a carrier gas such as air, oxygen, nitrogen or helium; antimicrobi...

434

Dust clusters in complex plasmas  

NASA Astrophysics Data System (ADS)

Dust cluster is a stable structure of negatively charged dust particles formed in complex plasmas. This paper briefly describes the dynamics of these objects. Dust clusters are confined by external applied and or self consistent electrostatic plasma fields. Dust cluster may be regarded as energy storage device which stores plasma thermal energy in the electrostatic fields of cluster. This energy is recovered when the cluster explodes upon removal of the confining potential. In this paper a model for the dust cluster explosion in the afterglow phase of a complex plasma discharge is described. The model is tested by MD simulations of dust particles in a confining potential. The nature of the explosion (caused by switching off the discharge) and the concomitant dust acceleration is found to depend critically on the pressure of the back ground neutral gas. At low gas pressure, the explosion is due to unshielded Coulomb repulsion between dust particles and yields maximum acceleration while in the high pressure regime it is due to shielded Yukawa repulsion and yields much feebler acceleration. These results are in agreement with recent experimental findings. The simulations also confirm a recently proposed electrostatic (ES) isothermal scaling relation, PE?Vd-2 (where PE is the ES is pressure of the dust particles and Vdis the confining volume).

Avinash, K.

2014-02-01

435

Strongly coupled plasma physics. Proceedings  

Microsoft Academic Search

Charged particles in dense matter exhibit strong correlations due to the exchange and Coulomb interactions, and thus make a strongly coupled plasma. Examples in laboratory and astrophysical settings include solid and liquid metals, semiconductors, charged particles in lower dimensions such as those trapped in interfacial states of condensed matter or beams, dense multi-ionic systems such a superionic conductors and inertial-confinement

S. Ichimaru

1990-01-01

436

Stationary plasma thruster plume characteristics  

Microsoft Academic Search

Stationary Plasma Thrusters (SPT's) are being investigated for application to a variety of near-term missions. This paper presents the results of a preliminary study of the thruster plume characteristics which are needed to assess spacecraft integration requirements. Langmuir probes, planar probes, Faraday cups, and a retarding potential analyzer were used to measure plume properties. For the design operating voltage of

Roger M. Myers; David H. Manzella

1994-01-01

437

Basic processes of plasma propulsion  

Microsoft Academic Search

The current density distribution, flow, pressure, and density fields are calculated for a (quasi-) steady nozzle-type magnetoplasmadynamic (MPD) thruster, based on a partially two dimensional approach, assuming a fully singly ionized plasma with an iso-thermal electron and an adiabatic ion behavior. In addition, for a given current rise, the current contour lines and the flow, pressure, and density fields within

Herbert O. Schrade; Monika Auweter-Kurtz; Helmut L. Kurtz

1987-01-01

438

Nonlinear dynamics and plasma transport  

SciTech Connect

In this paper we summarize the progress made over the last year in three different areas of research: (a) shear flow generation and reduced transport in fluids and plasma, (b) nonlinear dynamics and visualization of 3D flows, and (c) application of wavelet analysis to the study of fractal dimensions in experimental and numerical data.

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

1992-01-01

439

Space Plasmas and Lunar Electrodynamics  

E-print Network

and anthropogenic turbulence, studies of electrodynamic properties of the lunar environment, extremely long baseline, MARCH 23, 2005 #12;LOIS Lunar wake plasma WIND satellite results · Lunar wake electron density 104 m-3 at the edges · A host of so far unexplained emissions observed #12;LOIS Electromagnetic turbulence

440

TROPIX plasma interactions group report  

NASA Technical Reports Server (NTRS)

The purpose is to summarize the spacecraft charging analysis conducted by the plasma interactions group during the period from April 1993 to July 1993, on the proposed TROPIX spacecraft, and to make design recommendations which will limit the detrimental effects introduced by spacecraft charging. The recommendations were presented to the TROPIX study team at a Technical Review meeting held on 15 July 1993.

Herr, Joel L.; Chock, Ricaurte

1993-01-01

441

The Polar Plasma Wave Instrument  

NASA Technical Reports Server (NTRS)

The Plasma Wave Instrument on the Polar spacecraft is designed to provide measurements of plasma waves in the Earth's polar regions over the frequency range from 0.1 Hz to 800 kHz. Three orthogonal electric dipole antennas are used to detect electric fields, two in the spin plane and one aligned along the spacecraft spin axis. A magnetic loop antenna and a triaxial magnetic search coil antenna are used to detect magnetic fields. Signals from these antennas are processed by five receiver systems: a wideband receiver, a high-frequency waveform receiver, a low-frequency waveform receiver, two multichannel analyzers; and a pair of sweep frequency receivers. Compared to previous plasma wave instruments, the Polar plasma wave instrument has several new capabilities. These include (1) an expanded frequency range to improve coverage of both low- and high-frequency wave phenomena, (2) the ability to simultaneously capture signals from six orthogonal electric and magnetic field sensors, and (3) a digital wideband receiver with up to 8-bit resolution and sample rates as high as 249k samples s(exp -1).

Gurnett, D. A.; Persoon, A. M.; Randall, R. F.; Odem, D. L.; Remington, S. L.; Averkamp, T. F.; Debower, M. M.; Hospodarsky, G. B.; Huff, R. L.; Kirchner, D. L.

1995-01-01

442

Rotation of a magnetized plasma  

Microsoft Academic Search

The plasma rotation in the axial magnetic field of the linear machine Mistral [A. Escarguel, Eur. Phys. J. D 56, 209 (2010)] is well described by the assumption that the electrons injected from the source exit radially from the central column and are subject to the Lorentz force. Electrons and ions rotate together by ambipolarity. The solution of the momentum

B. M. Annaratone; A. Escarguel; T. Lefevre; C. Rebont; N. Claire; F. Doveil

2011-01-01

443

Alcohol consumption and plasma homocysteine.  

PubMed

A few reports show that consumption of spirits and of wine correlate with elevated plasma total homocysteine (tHcy), which is associated with the risk of cardiovascular disease. We analyzed the relation between tHcy and current daily ethanol consumption cross-sectionally in middle-aged Japanese men (n = 974, age 51-59 years). Plasma tHcy was positively associated with consumption of whiskey but not with consumption of shochu (Japanese spirits), sake, beer, or wine. Odds ratios of an increase in daily intake of 30 ml ethanol (approximately 1 standard deviation) for hyperhomocysteinemia (>14.0 micromol/l) were 2.58 (95% confidence interval, 1.29-5.14) for whiskey, 1.08 (0.78-1.50) for shochu, 0.99 (0.59-1.66) for sake, 0.98 (0.58-1.63) for beer, and 1.70 (0.31-9.50) for wine in a multivariate logistic regression analysis adjusted for the daily number of cigarettes smoked, physical activity, vegetable consumption, and serum creatinine levels. After inclusion of plasma folate and vitamin B12 in the multivariate analysis model, the association between whiskey ethanol consumption and hyperhomocysteinemia remained significant with odds ratio of 2.79 (1.36-5.72). These results suggest that whiskey consumption correlates with hyperhomocysteinemia independently of plasma folate or vitamin B12 or lifestyle factors in the population studied. PMID:16584970

Sakuta, Hidenari; Suzuki, Takashi

2005-10-01

444

The Plasma Membrane Calcium Pump  

NASA Technical Reports Server (NTRS)

Three aspect of cellular calcium metabolism in animal cells was discussed including the importance of the plasma membrane in calcium homeostasis, experiments dealing with the actual mechanism of the calcium pump, and the function of the pump in relationship to the mitochondria and to the function of calmodulin in the intact cell.

Rasmussen, H.

1983-01-01

445

How to model quantum plasmas  

E-print Network

Traditional plasma physics has mainly focused on regimes characterized by high temperatures and low densities, for which quantum-mechanical effects have virtually no impact. However, recent technological advances (particularly on miniaturized semiconductor devices and nanoscale objects) have made it possible to envisage practical applications of plasma physics where the quantum nature of the particles plays a crucial role. Here, I shall review different approaches to the modeling of quantum effects in electrostatic collisionless plasmas. The full kinetic model is provided by the Wigner equation, which is the quantum analog of the Vlasov equation. The Wigner formalism is particularly attractive, as it recasts quantum mechanics in the familiar classical phase space, although this comes at the cost of dealing with negative distribution functions. Equivalently, the Wigner model can be expressed in terms of $N$ one-particle Schr{\\"o}dinger equations, coupled by Poisson's equation: this is the Hartree formalism, which is related to the `multi-stream' approach of classical plasma physics. In order to reduce the complexity of the above approaches, it is possible to develop a quantum fluid model by taking velocity-space moments of the Wigner equation. Finally, certain regimes at large excitation energies can be described by semiclassical kinetic models (Vlasov-Poisson), provided that the initial ground-state equilibrium is treated quantum-mechanically. The above models are validated and compared both in the linear and nonlinear regimes.

G. Manfredi

2005-05-01

446

How to model quantum plasmas  

E-print Network

Abstract. Traditional plasma physics has mainly focused on regimes characterized by high temperatures and low densities, for which quantummechanical effects have virtually no impact. However, recent technological advances (particularly on miniaturized semiconductor devices and nanoscale objects) have made it possible to envisage practical applications of plasma physics where the quantum nature of the particles plays a crucial role. Here, I shall review different approaches to the modeling of quantum effects in electrostatic collisionless plasmas. The full kinetic model is provided by the Wigner equation, which is the quantum analog of the Vlasov equation. The Wigner formalism is particularly attractive, as it recasts quantum mechanics in the familiar classical phase space, although this comes at the cost of dealing with negative distribution functions. Equivalently, the Wigner model can be expressed in terms of N one-particle Schrödinger equations, coupled by Poisson’s equation: this is the Hartree formalism, which is related to the ‘multi-stream ’ approach of classical plasma physics. In order to reduce the complexity of the above approaches, it is possible to develop a quantum fluid model by taking velocity-space moments of the Wigner equation. Finally, certain regimes at large excitation energies can be described by semiclassical kinetic models (Vlasov-Poisson), provided that the initial ground-state equilibrium is treated quantum-mechanically. The above models are validated and compared both in the linear and nonlinear regimes. 1

Giovanni Manfredi; Université Henri Poincaré

2005-01-01

447

Plasma thrusters development in France  

NASA Astrophysics Data System (ADS)

This paper presents an overview of the FRENCH plasma propulsion activities. The main existing and future projects are described. The field of application of plasma propulsion is the station keeping and the orbit raising of geostationary telecommunication satellites (STENTOR) and the transfer of interplanetary vehicles such as Mars Sample Return. The works done in the frame of the preparation of the first commercial spacecraft as well as the preparation of the future and the associated Research and Technology program are described. The scientific activity supporting the development of Hall thrusters is on-going in the frame of the GDR (Groupement de Recherche) CNRS/CNES/Snecma Moteurs /ONERA on Plasma Propulsion. Several Russian entities are also involved: the MIREA (Moscow Institute of Radioelectronics and Automatics), of the RIAME MAI (Research Institute of Applied Mechanics and Electrodynamics - Moscow Aviation Institute) and of the SPT « father å Professor MOROZOV The industrial development activities are jointly conducted by Snecma Moteurs and Russian manufacturer FAKEL. The future developments are mainly dedicated to the use of electric propulsion for the orbit raising of telecommunications satellites which leads to the development of thrusters with higher thrust than those existing today. Works are also performed to develop and improve the tools necessary to evaluate the plume effects of plasma thrusters.

Rolfo, André; Cadiou, Anne; Secheresse, O.; Dumazert, P.; Gounot, V.; Ragot, X.; Mattei, N.; Grassin, T.; Garnero, P.

2002-07-01

448

Plasma Melter, Zybek Advanced Products  

USGS Multimedia Gallery

The plasma torch melter in Boulder, Colorado exists nowhere else in the world. The mixed and ground rock on the left in a 1-ton bag is fed into the melter to be made into glass. __________ The USGS has created man-made moon dirt, or regolith, to help NASA prepare for upcoming moon explorations. Fo...

2009-05-26

449

Coupled Monte Carlo neutral uid plasma simulation of Alcator C-Mod divertor plasma near detachment  

E-print Network

Coupled Monte Carlo neutral ± ¯uid plasma simulation of Alcator C-Mod divertor plasma near Abstract Using the coupled ¯uid plasma and Monte Carlo neutral transport code, B2-EIRENE, we simulate they are ionized. Coupled Monte Carlo neutral and ¯uid plasma transport codes similar to those used successfully

Karney, Charles

450

Investigations of plasma bullets formed in a non-thermal plasma jet in air  

Microsoft Academic Search

Recent studies have shown that low temperature atmospheric pressure plasma jets are formed by the propagation of small plasma bullets traveling at very high velocities in ambient air. However, the propagation mechanisms are still not well understood. In this paper we report experimental investigations of plasma bullets dynamics. The plasma jet was generated by a dielectric barrier discharge reactor fed

Julien Jarrige; Erdinc Karakas; Asma Begum; Mounir Laroussi

2009-01-01

451

Argon plasma vs. air plasma: Characteriazation and interaction with biological systems  

Microsoft Academic Search

Recently, there has been enormous progress in plasma medicine. New groups have joined this area of research. New plasma devices have been developed and tested for biomedical applications. The difference in plasma production methods and composition of input gases does not allow to directly compare plasmas produced by various devices and predict their effect on biological systems.

Tetyana Nosenko; Tetsuji Shimizu; Julia Zimmermann; Bernd Steffes; Gregor E. Morfill

2010-01-01

452

PHYSICS DESIGN GUIDELINES FOR ESTIMATING PLASMA PERFORMANCE IN A BURNING PLASMA EXPERIMENT (FIRE)  

E-print Network

PHYSICS DESIGN GUIDELINES FOR ESTIMATING PLASMA PERFORMANCE IN A BURNING PLASMA EXPERIMENT (FIRE The physics design guidelines for a next step, high- field tokamak, burning plasma experiment (FIRE, Fusion Ignition Research Experiment) have been developed as an update of the ITER Physics Basis (IPB). The plasma

453

Azimuthal plasma pressure gradient in quiet time plasma sheet L. R. Lyons,1  

E-print Network

Azimuthal plasma pressure gradient in quiet time plasma sheet X. Xing,1 L. R. Lyons,1 V 2 June 2009; accepted 16 June 2009; published 28 July 2009. [1] We have investigated the quiet-time. Runov, and U. Auster (2009), Azimuthal plasma pressure gradient in quiet time plasma sheet, Geophys. Res

California at Berkeley, University of

454

Plasma based charged-particle accelerators  

Microsoft Academic Search

Studies of charged-particle acceleration processes remain one of the most important areas of research in laboratory, space and astrophysical plasmas. In this paper, we present the underlying physics and the present status of high gradient and high energy plasma accelerators. We will focus on the acceleration of charged particles to relativistic energies by plasma waves that are created by intense

R Bingham; J T Mendonça; P K Shukla

2004-01-01

455

Numerical Simulations of Hypervelocity Plasma Jets  

Microsoft Academic Search

Numerical simulations with comparisons to experiments of hypervelocity plasma jets in development at HyperV Technologies Corp. are presented. The focus will be on the new plasma jet designed to drive rotation in the University of Maryland MCX experiment. Performance of coaxial plasma jets is typically limited by the blow-by instability. Extensive numerical modeling with the Mach 2 code was used

M. W. Phillips; F. D. Witherspoon; A. Case; S. J. Messer; T. P. Hughes; D. R. Welch; I. N. Bogatu; S. R. Galkin; J. S. Kim

2007-01-01

456

Planar controlled zone microwave plasma system  

DOEpatents

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.

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

2011-10-04

457

SYLLABUS: PHYSICS 8120 PLASMA PHYSICS SPRING 2005  

E-print Network

SYLLABUS: PHYSICS 8120 PLASMA PHYSICS SPRING 2005 Instructor: Prof. Paul J. Wiita Class Timings at an appropriate level. Other texts to which you may wish to refer: 1) Peter A. Sturrock, Plasma Physics 2) Nicholas A. Krall & Alvin W. Trivelpiece, Principles of Plasma Physics 3) Lyman Spitzer, Jr., Physics

Wiita, Paul J.

458

SYLLABUS: PHYSICS 8120 PLASMA PHYSICS FALL 2007  

E-print Network

SYLLABUS: PHYSICS 8120 PLASMA PHYSICS FALL 2007 Instructor: Prof. Paul J. Wiita Class Timings to see me at some other time. Required Text: Russell M. Kulsrud, Plasma Physics for Astrophysics and Fluids 2) Peter A. Sturrock, Plasma Physics 3) Nicholas A. Krall & Alvin W. Trivelpiece, Principles

Wiita, Paul J.

459

ON THE LANDAU APPROXIMATION IN PLASMA PHYSICS  

E-print Network

ON THE LANDAU APPROXIMATION IN PLASMA PHYSICS R. ALEXANDRE AND C. VILLANI Abstract. This paper of his important works in plasma physics, established the kinetic equation which is now called after him interacting through binary collisions. Since then, this equation has been widely in use in plasma physics, see

Villani, Cédric

460

ccsd00001721, Rational paradigm of plasma physics  

E-print Network

ccsd­00001721, version 1 ­ 27 Sep 2004 Rational paradigm of plasma physics V.I. Erofeev Institute distribution evolution during this scattering [8]. With this, an extensive revision of the plasma physics be said about all the current plasma physical theory. An appear of the given tradition was conditioned

461

Plasma membrane proteome in Arabidopsis and rice  

Microsoft Academic Search

Plant cells contain many membrane systems that are specially adapted to perform particular functions. In plant cells, the processing of signals that are involved in responses to biotic and abiotic stressors occurs in the plasma membrane. Therefore, characterization of the plasma membrane proteome can provide new insights into the functions of various plant membrane systems. Plant plasma membrane proteomics can

Setsuko Komatsu

2008-01-01

462

Waves and Instabilities in Magnetized Dusty Plasmas  

Microsoft Academic Search

The status of waves and instabilities in magnetized dusty plasmas is summarized. The effects of an external magnetic field on low-frequency electrostatic and electromagnetic waves in dusty plasmas are discussed. The kinetic and hydrodynamic instabilities are shown to excite magnetized dusty plasma waves. The presence of the latter can give rise to an oscillatory wake-potential which can be responsible for

Padma K. Shukla

1998-01-01

463

Waves and Instabilities in Magnetized Dusty Plasmas  

Microsoft Academic Search

The status of waves and instabilities in magnetized dusty plasmas is summarized. The effects of an external magnetic field on low-frequency electrostatic and electromagnetic waves in dusty plasmas are discussed. The kinetic and hydrodynamic instabilities are shown to excite magnetized dusty plasma waves. The presence of the latter can give rise to an oscillatory wake-potential which can be responsible for

Padma K. Shukla

1999-01-01

464

Electrostatic surface waves in a dusty plasma  

Microsoft Academic Search

Electromagnetic dispersion relation of a surface wave is obtained propagating on an interface between a vacuum and a dusty plasma, which consists of electrons and ions on their respective Boltzmann distributions and cold dust particles providing the inertia of the plasma and carrying a certain portion of the negative charge of the plasma. The electrostatic spectrum is interesting, since the

Hee J. Lee

2000-01-01

465

Multi-bunch plasma wakefield acceleration experiments  

Microsoft Academic Search

Summary form only given. Plasmas can sustain extremely large electric field that can lead to large particle energy gains in short plasma-based accelerators. These fields can be excited or driven by short particle bunches in a scheme known as the plasma wakefield accelerator (PWFA). However, a equally important parameter for application to a future particle accelerator is the efficiency of

Patric Muggli; E. Kallos; T. Katsouleas; V. Yakimenko; M. Babzien; K. P. Kusche; I. Pogorelsky; W. Kimura

2008-01-01

466

Submitted IEEE Trans. Plasma Science Shvets Fisch  

E-print Network

of the electric sustain. plasma-based accelerator [2], parti- energy from a longitudinal plasma wave whose phase or parting with momentum through impulsive It turns out excitation of regular is anal- ogous to former while pulse without energy later tended consistently taking into account longitudinal electric plasma

467

On the Electrodynamics of Nonequilibrium Plasmas  

Microsoft Academic Search

The problems of basic plasma physics play a very important rôle in the development of modern physics. In particular the collective plasma phenomena which can not be explained in terms of any linear theory but instead have to be described by means of largeamplitude and turbulence analysis are of outstanding interest. The experimental situations in present day applications of plasma

Hans Wilhelmsson

1975-01-01

468

21 CFR 640.60 - Source Plasma.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2010-04-01 true Source Plasma. 640.60 Section 640.60 Food and Drugs...STANDARDS FOR HUMAN BLOOD AND BLOOD PRODUCTS Source Plasma § 640.60 Source Plasma. The proper name of the product shall be...

2011-04-01

469

21 CFR 640.30 - Plasma.  

Code of Federal Regulations, 2011 CFR

...Drugs 7 2011-04-01 2010-04-01 true Plasma. 640.30 Section 640.30 Food and Drugs...ADDITIONAL STANDARDS FOR HUMAN BLOOD AND BLOOD PRODUCTS Plasma § 640.30 Plasma. (a) Proper name and definition . The...

2011-04-01

470

21 CFR 640.30 - Plasma.  

Code of Federal Regulations, 2012 CFR

...Drugs 7 2012-04-01 2012-04-01 false Plasma. 640.30 Section 640.30 Food and Drugs...ADDITIONAL STANDARDS FOR HUMAN BLOOD AND BLOOD PRODUCTS Plasma § 640.30 Plasma. (a) Proper name and definition . The...

2012-04-01

471

21 CFR 640.60 - Source Plasma.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Source Plasma. 640.60 Section 640.60 Food and Drugs...STANDARDS FOR HUMAN BLOOD AND BLOOD PRODUCTS Source Plasma § 640.60 Source Plasma. The proper name of the product shall be...

2012-04-01

472

21 CFR 640.30 - Plasma.  

Code of Federal Regulations, 2013 CFR

...Drugs 7 2013-04-01 2013-04-01 false Plasma. 640.30 Section 640.30 Food and Drugs...ADDITIONAL STANDARDS FOR HUMAN BLOOD AND BLOOD PRODUCTS Plasma § 640.30 Plasma. (a) Proper name and definition . The...

2013-04-01

473

21 CFR 640.60 - Source Plasma.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Source Plasma. 640.60 Section 640.60 Food and Drugs...STANDARDS FOR HUMAN BLOOD AND BLOOD PRODUCTS Source Plasma § 640.60 Source Plasma. The proper name of the product shall be...

2013-04-01

474

21 CFR 640.30 - Plasma.  

...Drugs 7 2014-04-01 2014-04-01 false Plasma. 640.30 Section 640.30 Food and Drugs...ADDITIONAL STANDARDS FOR HUMAN BLOOD AND BLOOD PRODUCTS Plasma § 640.30 Plasma. (a) Proper name and definition . The...

2014-04-01

475

21 CFR 640.60 - Source Plasma.  

...2014-04-01 2014-04-01 false Source Plasma. 640.60 Section 640.60 Food and Drugs...STANDARDS FOR HUMAN BLOOD AND BLOOD PRODUCTS Source Plasma § 640.60 Source Plasma. The proper name of the product shall be...

2014-04-01

476

General Properties of High Temperature Plasmas  

E-print Network

- tion of these plasma properties was made possible by a small probe (Langmuir probe) which is still widely used to diagnose low-temperature plasmas. By varying the probe bias voltage, Langmuir was able voltage, high current switching device.) In astro- and space physics, the importance of plasma interaction

Saskatchewan, University of

477

Modeling and simulation of plasma processing equipment  

Microsoft Academic Search

Currently plasma processing technology is utilized in a wide range of applications including advanced Integrated Circuit (IC) fabrication. Traditionally, plasma processing equipments have been empirically designed and optimized at great expense of development time and cost. This research proposes the development of a first principle based, multidimensional plasma process simulator with the aim of enhancing the equipment design procedure. The

Heon Chang Kim

1998-01-01

478

21 CFR 640.30 - Plasma.  

Code of Federal Regulations, 2010 CFR

...Drugs 7 2010-04-01 2010-04-01 false Plasma. 640.30 Section 640.30 Food and Drugs...ADDITIONAL STANDARDS FOR HUMAN BLOOD AND BLOOD PRODUCTS Plasma § 640.30 Plasma. (a) Proper name and definition . The...

2010-04-01

479

21 CFR 640.60 - Source Plasma.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Source Plasma. 640.60 Section 640.60 Food and Drugs...STANDARDS FOR HUMAN BLOOD AND BLOOD PRODUCTS Source Plasma § 640.60 Source Plasma. The proper name of the product shall be...

2010-04-01

480

Designing plasmas for chronic wound disinfection  

NASA Astrophysics Data System (ADS)

Irradiation with low-temperature atmospheric-pressure plasma provides a promising method for chronic wound disinfection. To be efficient for this purpose, plasma should meet the following criteria: it should significantly reduce bacterial density in the wounded area, cause a long-term post-irradiation inhibition of bacterial growth, yet without causing any negative effect on human cells. In order to design plasmas that would satisfy these requirements, we assessed the relative contribution of different components with respect to bactericidal properties due to irradiation with argon plasma. We demonstrate that plasma-generated UV radiation is the main short-term sterilizing factor of argon plasma. On the other hand, plasma-generated reactive nitrogen species (RNS) and reactive oxygen species (ROS) cause a long-term 'after-irradiation' inhibition of bacterial growth and, therefore, are important for preventing wound recolonization with bacteria between two treatments. We also demonstrate that at certain concentrations plasma-generated RNS and ROS cause significant reduction of bacterial density, but have no adverse effect on human skin cells. Possible mechanisms of the different effects of plasma-generated reactive species on bacteria and human cells are discussed. The results of this study suggest that argon plasma for therapeutic purposes should be optimized in the direction of reducing the intensity of plasma-generated UV radiation and increasing the density of non-UV plasma products.

Nosenko, T.; Shimizu, T.; Morfill, G. E.

2009-11-01