WorldWideScience

Sample records for plasma space potential

  1. Bifurcation of space-charge wave in a plasma waveguide including the wake potential effect

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Myoung-Jae [Department of Physics and Research Institute for Natural Sciences, Hanyang University, Seoul 04763 (Korea, Republic of); Jung, Young-Dae, E-mail: ydjung@hanyang.ac.kr [Department of Applied Physics and Department of Bionanotechnology, Hanyang University, Ansan, Kyunggi-Do 15588, South Korea and Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180-3590 (United States)

    2016-09-15

    The wake potential effects on the propagation of the space-charge dust ion-acoustic wave are investigated in a cylindrically bounded dusty plasma with the ion flow. The results show that the wake potential would generate the double frequency modes in a cylindrically bounded dusty plasma. It is found that the upper mode of the wave frequency with the root of higher-order is smaller than that with the root of lower-order in intermediate wave number domains. However, the lower mode of the scaled wave frequency with the root of higher-order is found to be greater than that with the root of lower-order. It is found that the influence in the order of the root of the Bessel function on the wave frequency of the space-charge dust-ion-acoustic wave in a cylindrically confined dusty plasma decreases with an increase in the propagation wave number. It is also found that the double frequency modes increase with increasing Mach number due to the ion flow in a cylindrical dusty plasma. In addition, it is found that the upper mode of the group velocity decreases with an increase in the scaled radius of the plasma cylinder. However, it is shown that the lower mode of the scaled group velocity of the space-charge dust ion acoustic wave increases with an increase in the radius of the plasma cylinder. The variation of the space-charge dust-ion-acoustic wave due to the wake potential and geometric effects is also discussed.

  2. Bifurcation of space-charge wave in a plasma waveguide including the wake potential effect

    Science.gov (United States)

    Lee, Myoung-Jae; Jung, Young-Dae

    2016-09-01

    The wake potential effects on the propagation of the space-charge dust ion-acoustic wave are investigated in a cylindrically bounded dusty plasma with the ion flow. The results show that the wake potential would generate the double frequency modes in a cylindrically bounded dusty plasma. It is found that the upper mode of the wave frequency with the root of higher-order is smaller than that with the root of lower-order in intermediate wave number domains. However, the lower mode of the scaled wave frequency with the root of higher-order is found to be greater than that with the root of lower-order. It is found that the influence in the order of the root of the Bessel function on the wave frequency of the space-charge dust-ion-acoustic wave in a cylindrically confined dusty plasma decreases with an increase in the propagation wave number. It is also found that the double frequency modes increase with increasing Mach number due to the ion flow in a cylindrical dusty plasma. In addition, it is found that the upper mode of the group velocity decreases with an increase in the scaled radius of the plasma cylinder. However, it is shown that the lower mode of the scaled group velocity of the space-charge dust ion acoustic wave increases with an increase in the radius of the plasma cylinder. The variation of the space-charge dust-ion-acoustic wave due to the wake potential and geometric effects is also discussed.

  3. Derivation and Testing of Computer Algorithms for Automatic Real-Time Determination of Space Vehicle Potentials in Various Plasma Environments

    Science.gov (United States)

    1988-05-31

    COMPUTER ALGORITHMS FOR AUTOMATIC REAL-TIME DETERMINATION OF SPACE VEHICLE POTENTIALS IN VARIOUS PLASMA ENVIRONMENTS May 31, 1988 Stanley L. Spiegel...crrnaion DiviSiofl 838 12 2 DERIVATION AND TESTING OF COMPUTER ALGORITHMS FOR AUTOMATIC REAL-TIME DETERMINATION OF SPACE VEHICLE POTENTIALS IN VARIOUS...S.L., "Derivation and testing of computer algorithms for automatic real time determination of space vehicle poteuatials in various plasma

  4. Space charge, plasma potential and electric field distributions in HiPIMS discharges of varying configuration

    Science.gov (United States)

    Liebig, B.; Bradley, J. W.

    2013-08-01

    An electron-emitting (emissive) probe has been used to study the temporal and spatial distribution of the plasma potential during high-power impulse magnetron sputtering (HiPIMS) discharges with various substrate and magnetic field configurations. The average power was 700 W, with a repetition frequency of 100 Hz and pulse duration of 100 µs. Strongly negative plasma potentials exceeding -300 V and electric fields up to 10 kV m-1, caused by strong separation of charges with net charge carrier densities Δn of about 1014 m-3, were observed during the ignition of the discharge. The spatial distribution of the plasma potential in the stable stage of the discharge showed values consistently 5 V more negative for a floating substrate compared with a grounded one, so enhancing electron transport around the insulated substrate to grounded walls. However, this change in the electrical configuration of the plasma does not alter significantly the fraction of ionized sputtered particles (of about 30%) that can potentially reach the substrate. By changing the degree of unbalance of the sputtering source, we find a strong correlation between the electric field strength in the magnetic trap (created through charge separation) and the absolute value (and shape) of the magnetic field. For the more unbalanced magnetron, a flattening of the plasma potential structure (decrease in the axial electric field) was observed close to the target. Our findings show in principle that manipulation of the potential barrier close to the target through changing the magnetic field can regulate the proportion of sputtered and ionized species reaching the substrate.

  5. Physics and potentials of fissioning plasmas for space power and propulsion

    Science.gov (United States)

    Thom, K.; Schwenk, F. C.; Schneider, R. T.

    1976-01-01

    Fissioning uranium plasmas are the nuclear fuel in conceptual high-temperature gaseous-core reactors for advanced rocket propulsion in space. A gaseous-core nuclear rocket would be a thermal reactor in which an enriched uranium plasma at about 10,000 K is confined in a reflector-moderator cavity where it is nuclear critical and transfers its fission power to a confining propellant flow for the production of thrust at a specific impulse up to 5000 sec. With a thrust-to-engine weight ratio approaching unity, the gaseous-core nuclear rocket could provide for propulsion capabilities needed for manned missions to the nearby planets and for economical cislunar ferry services. Fueled with enriched uranium hexafluoride and operated at temperatures lower than needed for propulsion, the gaseous-core reactor scheme also offers significant benefits in applications for space and terrestrial power. They include high-efficiency power generation at low specific mass, the burnup of certain fission products and actinides, the breeding of U-233 from thorium with short doubling times, and improved convenience of fuel handling and processing in the gaseous phase.

  6. A new Differential Equation for Anomalous Diffusion with Potential Applications to Nonlinear Space Plasmas

    Science.gov (United States)

    Watkins, N. W.; Credgington, D.; Sanchez, R.; Chapman, S. C.

    2007-12-01

    Since the 1960s Mandelbrot has advocated the use of fractals for the description of the non-Euclidean geometry of many aspects of nature. In particular he proposed two kinds of model to capture persistence in time (his Joseph effect, common in hydrology and with fractional Brownian motion as the prototpe) and/or prone to heavy tailed jumps (the Noah effect, typical of economic indices, for which he proposed Lévy flights as an exemplar). Both effects are now well demonstrated in space plasmas, notably in indices quantifying Earth's auroral currents and in the turbulent solar wind. Models have, however, typically emphasised one of the Noah and Joseph parameters (the Lévy exponent μ and the temporal exponent β) at the other's expense. I will describe recent work [1] in which we studied a simple self-affine stable model-linear fractional stable motion, LFSM, which unifies both effects. I will discuss how this resolves some contradictions seen in earlier work. Such Noah-Joseph hybrid ("ambivalent" [2]) behaviour is highly topical in physics but is typically studied in the paradigm of the continuous time random walk (CTRW) [2,3] rather than LFSM. I will clarify the physical differences between these two pictures and present a recently-derived diffusion equation for LFSM. This replaces the second order spatial derivative in the equation of fBm [4] with a fractional derivative of order μ, but retains a diffusion coefficient with a power law time dependence rather than a fractional derivative in time (c.f. [2,3]). Intriguingly the self-similarity exponent extracted from the CTRW differs from that seen in LFSM. In the CTRW it is the ratio of μ to a temporal exponent, in LFSM it is an additive function of them. I will also show work in progress using an LFSM model and simple analytic scaling arguments to study the problem of the area between an LFSM curve and a threshold-related to the burst size measure introduced by Takalo and Consolini into solar- terrestrial physics

  7. Space Plasma Effects

    Directory of Open Access Journals (Sweden)

    Miguel Herraiz

    2009-06-01

    Full Text Available

    This paper summarizes the activities carried out by WP 3.1 of WG 3 of COST 296 action. The Work Package

    deals mostly with medium and large ionospheric structures that impacts on GNSS signals. In the research done

    by this European team, particular attention was given to the ionosphere/space weather monitoring, to the analysis

    of the variability of the ionospheric plasma during quiet and disturbed conditions and to the characterization

    of the behavior of low latitudes ionospheric depletions or bubbles and the spatial and temporal gradients of total electron contet.


  8. Space plasma physics research

    Science.gov (United States)

    Comfort, Richard H.; Horwitz, James L.

    1993-01-01

    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.

  9. Space Plasma Physics

    Science.gov (United States)

    Wu, S. T.

    2000-01-01

    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).

  10. Space and Astrophysical Plasmas : Space and astrophysical plasmas: Pervasive problems

    Indian Academy of Sciences (India)

    Chanchal Uberoi

    2000-11-01

    The observations and measurements given by Earth orbiting satellites, deep space probes, sub-orbital systems and orbiting astronomical observatories point out that there are important physical processes which are responsible for a wide variety of phenomena in solar-terrestrial, solar-system and astrophysical plasmas. In this review these topics are exemplified both from an observational and a theoretical point of view.

  11. Active probing of space plasmas

    Science.gov (United States)

    Chan, Chang; Silevitch, Michael B.; Villalon, Elena

    1989-09-01

    During the course of the research period our efforts were focused on the following areas: (1) An examination of stochastic acceleration mechanisms in the ionosphere; (2) A study of nonequilibrium dynamics of the coupled magnetosphere - ionosphere system; and (3) Laboratory studies of active space experiments. Reprints include: Dynamics of charged particles in the near wake of a very negatively charged body -- Laboratory experiment and numerical simulation; Laboratory study of the electron temperature in the near wake of a conducting body; New model for auroral breakup during substorms; Substorm breakup on closed field lines; New model for substorm on sets -- The pre-breakup and triggering regimes; Model of the westward traveling surge and the generation of Pi 2 pulsations; Ionospheric electron acceleration by electromagnetic waves near regions of plasma resonances; Relativistic particle acceleration by obliquely propagating electromagnetic fields; Some consequences of intense electromagnetic wave injection into space plasmas.

  12. Plasma Physics An Introduction to Laboratory, Space, and Fusion Plasmas

    CERN Document Server

    Piel, Alexander

    2010-01-01

    Plasma Physics gives a comprehensive introduction to the basic processes in plasmas and demonstrates that the same fundamental concepts describe cold gas-discharge plasmas, space plasmas, and hot fusion plasmas. Starting from particle drifts in magnetic fields, the principles of magnetic confinement fusion are explained and compared with laser fusion. Collective processes are discussed in terms of plasma waves and instabilities. The concepts of plasma description by magnetohydrodynamics, kinetic theory, and particle simulation are stepwise introduced. Space charge effects in sheath regions, double layers and plasma diodes are given the necessary attention. The new fundamental mechanisms of dusty plasmas are explored and integrated into the framework of conventional plasmas. The book concludes with a brief introduction to plasma discharges. Written by an internationally renowned researcher in experimental plasma physics, the text keeps the mathematical apparatus simple and emphasizes the underlying concepts. T...

  13. Plasma physics an introduction to laboratory, space, and fusion plasmas

    CERN Document Server

    Piel, Alexander

    2017-01-01

    The enlarged new edition of this textbook provides a comprehensive introduction to the basic processes in plasmas and demonstrates that the same fundamental concepts describe cold gas-discharge plasmas, space plasmas, and hot fusion plasmas. Starting from particle drifts in magnetic fields, the principles of magnetic confinement fusion are explained and compared with laser fusion. Collective processes are discussed in terms of plasma waves and instabilities. The concepts of plasma description by magnetohydrodynamics, kinetic theory, and particle simulation are stepwise introduced. Space charge effects in sheath regions, double layers and plasma diodes are given the necessary attention. The novel fundamental mechanisms of dusty plasmas are explored and integrated into the framework of conventional plasmas. The book concludes with a concise description of modern plasma discharges. Written by an internationally renowned researcher in experimental plasma physics, the text keeps the mathematical apparatus simple a...

  14. Space plasma physics results from Spacelab 1

    Science.gov (United States)

    Burch, J. L.

    1985-01-01

    The Spacelab 1 payload carried several instrument systems which together investigated a number of space plasma phenomena. These experiments used the Space Shuttle Orbiter as a platform for making controlled particle-beam, plasma and neutral gas inputs to the ionosphere and magnetosphere and for observing the outputs produced. Spacelab 1 space-plasma investigations included the Space Experiments with Particle Accelerators (SEPAC), Phenomena Induced by Charged Particle Beams (PICPAB), Atmospheric Emissions Photometric Imaging (AEPI) and the Low Energy Electron Spectrometer and Magnetometer. Among the major phenomena investigated both singly and jointly by these experiments are vehicle charging and neutralization, beam-plasma and wave-particle interactions, anomalous ionization phenomena produced by neutral-gas and plasma injections and several phenomena induced by modulated particle beam injections.

  15. Surface waves on a quantum plasma half-space

    CERN Document Server

    Lázár, M; Smolyakov, A

    2007-01-01

    Surface modes are coupled electromagnetic/electrostatic excitations of free electrons near the vacuum-plasma interface and can be excited on a sufficiently dense plasma half-space. They propagate along the surface plane and decay in either sides of the boundary. In such dense plasma models, which are of interest in electronic signal transmission or in some astrophysical applications, the dynamics of the electrons is certainly affected by the quantum effects. Thus, the dispersion relation for the surface wave on a quantum electron plasma half-space is derived by employing the quantum hydrodynamical (QHD) and Maxwell-Poison equations. The QHD include quantum forces involving the Fermi electron temperature and the quantum Bohm potential. It is found that, at room temperature, the quantum effects are mainly relevant for the electrostatic surface plasma waves in a dense gold metallic plasma.

  16. Landau damping in space plasmas

    Science.gov (United States)

    Thorne, Richard M.; Summers, Danny

    1991-01-01

    The Landau damping of electrostatic Langmuir waves and ion-acoustic waves in a hot, isotropic, nonmagnetized, generalized Lorentzian plasma is analyzed using the modified plasma dispersion function. Numerical solutions for the real and imaginary parts of the wave frequency omega sub 0 - (i)(gamma) have been obtained as a function of the normalized wave number (k)(lambda sub D), where lambda sub D is the electron Debye length. For both particle distributions the electrostatic modes are found to be strongly damped at short wavelengths. At long wavelengths, this damping becomes less severe, but the attenuation of Langmuir waves is much stronger for a generalized Lorentzian plasma than for a Maxwellian plasma. It is concluded that Landau damping of ion-acoustic waves is only slightly affected by the presence of a high energy tail, but is strongly dependent on the ion temperature.

  17. Space plasma physics: I - Stationary processes

    Science.gov (United States)

    Hasegawa, Akira; Sato, Tetsuya

    1989-01-01

    The physics of stationary processes in space plasmas is examined theoretically in an introduction intended for graduate students. The approach involves the extensive use of numerical simulations. Chapters are devoted to fundamental principles, small-amplitude waves, and the stationary solar plasma system; typical measurement data and simulation results are presented graphically.

  18. Nonextensivity, Complexity and Nonlinearity in Space Plasmas

    Science.gov (United States)

    Pavlos, G. P.

    2017-01-01

    Experimental time series, extracted from many and different space plasma systems corresponding to, solar wind, magnetospheric and other space plasma systems reveal common dynamical, geometrical, or statistical characteristics. Such characteristics are the low dimensionality, the typical intermittent turbulence multifractality, the temporal or spatial multiscale correlations and power laws scale invariance, non Gaoussianity and others. This universal aspect of experimental time series profiles was understood in the past as the chaos or SOC universality. However, after two or three decades of theoretical development in understanding of the nonlinearity and complexity, we can give a more compact theoretical description of the underline universal physical processes that produce the experimental time series complexity. Finally, in this study, we present and explain the modern complex set of theoretical concepts from the point of view of physics as the unification theory of nonlinear theory of non-equilibrium plasma systems as well as the presupposed theoretical framework of time series analysis of space plasma charachteristics.

  19. Nongyrotropic particle distributions in space plasmas

    Directory of Open Access Journals (Sweden)

    U. Motschmann

    Full Text Available In nonstationary, strong inhomogeneous or open plasmas particle orbits are rather complicated. If the nonstationary time scale is smaller than the gyration period, if the inhomogeneity scale is smaller than the gyration radius, i.e. at magnetic plasma boundaries, or if the plasma has sources and sinks in phase space, then nongyrotropic distribution functions occur. The stability of such plasma configurations is studied in the framework of linear dispersion theory. In an open plasma nongyrotropy drives unstable waves parallel and perpendicular to the background magnetic field, whereas in the gyrotropic limit the plasma is stable. In nonstationary plasmas nongyrotropy drives perpendicular unstable waves only. Temporal modulation couples a seed mode with its side lobes and thus it renders unstable wave growth more difficult. As an example of an inhomogeneous plasma a magnetic halfspace is discussed. In a layer with thickness of the thermal proton gyroradius a nongyrotropic distribution is formed which may excite unstable parallel and perpendicular propagating waves.

    Key words. Interplanetary physics (plasma waves and turbulence · Ionosphere (plasma waves and instabilities · Magnetospheric physics (plasma waves and instabilities

  20. Low-Frequency Waves in Space Plasmas

    Science.gov (United States)

    Keiling, Andreas; Lee, Dong-Hun; Nakariakov, Valery

    2016-02-01

    Low-frequency waves in space plasmas have been studied for several decades, and our knowledge gain has been incremental with several paradigm-changing leaps forward. In our solar system, such waves occur in the ionospheres and magnetospheres of planets, and around our Moon. They occur in the solar wind, and more recently, they have been confirmed in the Sun's atmosphere as well. The goal of wave research is to understand their generation, their propagation, and their interaction with the surrounding plasma. Low-frequency Waves in Space Plasmas presents a concise and authoritative up-to-date look on where wave research stands: What have we learned in the last decade? What are unanswered questions? While in the past waves in different astrophysical plasmas have been largely treated in separate books, the unique feature of this monograph is that it covers waves in many plasma regions, including: Waves in geospace, including ionosphere and magnetosphere Waves in planetary magnetospheres Waves at the Moon Waves in the solar wind Waves in the solar atmosphere Because of the breadth of topics covered, this volume should appeal to a broad community of space scientists and students, and it should also be of interest to astronomers/astrophysicists who are studying space plasmas beyond our Solar System.

  1. Cold Atmospheric Plasma Technology for Decontamination of Space Equipment

    Science.gov (United States)

    Thomas, Hubertus; Rettberg, Petra; Shimizu, Tetsuji; Thoma, Markus; Morfill, Gregor; Zimmermann, Julia; Müller, Meike; Semenov, Igor

    2016-07-01

    Cold atmospheric plasma (CAP) technology is very fast and effective in inactivation of all kinds of pathogens. It is used in hygiene and especially in medicine, since the plasma treatment can be applied to sensitive surfaces, like skin, too. In a first study to use CAP for the decontamination of space equipment we could show its potential as a quite promising alternative to the standard "dry heat" and H2O2 methods [Shimizu et al. Planetary and Space Science, 90, 60-71. (2014)]. In a follow-on study we continue the investigations to reach high application level of the technology. First, we redesign the actual setup to a plasma-gas circulation system, increasing the effectivity of inactivation and the sustainability. Additionally, we want to learn more about the plasma chemistry processes involved in the inactivation. Therefore, we perform detailed plasma and gas measurements and compare them to numerical simulations. The latter will finally be used to scale the decontamination system to sizes useful also for larger space equipment. Typical materials relevant for space equipment will be tested and investigated on surface material changes due to the plasma treatment. Additionally, it is planned to use electronic boards and compare their functionality before and after the CAP expose. We will give an overview on the status of the plasma decontamination project funded by the Bavarian Ministry of Economics.

  2. A note on dust grain charging in space plasmas

    Science.gov (United States)

    Rosenberg, M.; Mendis, D. A.

    1992-01-01

    Central to the study of dust-plasma interactions in the solar system is the electrostatic charging of dust grains. While previous calculations have generally assumed that the distributions of electrons and ions in the plasma are Maxwellian, most space plasmas are observed to have non-Maxwellian tails and can often be fit by a generalized Lorentzian (kappa) distribution. Here we use such a distribution to reevaluate the grain potential, under the condition that the dominant currents to the grain are due to electron and ion collection, as is the case in certain regions of space. The magnitude of the grain potential is found to be larger than that in a Maxwellian plasma as long as the electrons are described by a kappa distribution: this enhancement increased with ion mass and decreasing electron kappa. The modification of the grain potential in generalized Lorentzian plasmas has implications for both the physics (e.g., grain growth and disruption) and the dynamics of dust in space plasmas. These are also briefly discussed.

  3. Space plasma physics stationary processes

    CERN Document Server

    Hasegawa, Akira

    1989-01-01

    During the 30 years of space exploration, important discoveries in the near-earth environment such as the Van Allen belts, the plasmapause, the magnetotail and the bow shock, to name a few, have been made. Coupling between the solar wind and the magnetosphere and energy transfer processes between them are being identified. Space physics is clearly approaching a new era, where the emphasis is being shifted from discoveries to understanding. One way of identifying the new direction may be found in the recent contribution of atmospheric science and oceanography to the development of fluid dynamics. Hydrodynamics is a branch of classical physics in which important discoveries have been made in the era of Rayleigh, Taylor, Kelvin and Helmholtz. However, recent progress in global measurements using man-made satellites and in large scale computer simulations carried out by scientists in the fields of atmospheric science and oceanography have created new activities in hydrodynamics and produced important new discover...

  4. Plasma Interaction with International Space Station High Voltage Solar Arrays

    Science.gov (United States)

    Heard, John W.

    2002-01-01

    The International Space Station (ISS) is presently being assembled in low-earth orbit (LEO) operating high voltage solar arrays (-160 V max, -140 V typical with respect to the ambient atmosphere). At the station's present altitude, there exists substantial ambient plasma that can interact with the solar arrays. The biasing of an object to an electric potential immersed in plasma creates a plasma "sheath" or non-equilibrium plasma around the object to mask out the electric fields. A positively biased object can collect electrons from the plasma sheath and the sheath will draw a current from the surrounding plasma. This parasitic current can enter the solar cells and effectively "short out" the potential across the cells, reducing the power that can be generated by the panels. Predictions of collected current based on previous high voltage experiments (SAMPIE (Solar Array Module Plasma Interactions Experiment), PASP+ (Photovoltaic Array Space Power) were on the order of amperes of current. However, present measurements of parasitic current are on the order of several milliamperes, and the current collection mainly occurs during an "eclipse exit" event, i.e., when the space station comes out of darkness. This collection also has a time scale, t approx. 1000 s, that is much slower than any known plasma interaction time scales. The reason for the discrepancy between predictions and present electron collection is not understood and is under investigation by the PCU (Plasma Contactor Unit) "Tiger" team. This paper will examine the potential structure within and around the solar arrays, and the possible causes and reasons for the electron collection of the array.

  5. Micro- to macroscale perspectives on space plasmas

    Science.gov (United States)

    Eastman, Timothy E.

    1993-01-01

    The Earth's magnetosphere is the most accessible of natural collisionless plasma environments; an astrophysical plasma 'laboratory'. Magnetospheric physics has been in an exploration phase since its origin 35 years ago but new coordinated, multipoint observations, theory, modeling, and simulations are moving this highly interdisciplinary field of plasma science into a new phase of synthesis and understanding. Plasma systems are ones in which binary collisions are relatively negligible and collective behavior beyond the microscale emerges. Most readily accessible natural plasma systems are collisional and nearest-neighbor classical interactions compete with longer-range plasma effects. Except for stars, most space plasmas are collisionless, however, and the effects of electrodynamic coupling dominate. Basic physical processes in such collisionless plasmas occur at micro-, meso-, and macroscales that are not merely reducible to each other in certain crucial ways as illustrated for the global coupling of the Earth's magnetosphere and for the nonlinear dynamics of charged particle motion in the magnetotail. Such global coupling and coherence makes the geospace environment, the domain of solar-terrestrial science, the most highly coupled of all physical geospheres.

  6. Space Station Freedom solar array panels plasma interaction test facility

    Science.gov (United States)

    Martin, Donald F.; Mellott, Kenneth D.

    1989-01-01

    The Space Station Freedom Power System will make extensive use of photovoltaic (PV) power generation. The phase 1 power system consists of two PV power modules each capable of delivering 37.5 KW of conditioned power to the user. Each PV module consists of two solar arrays. Each solar array is made up of two solar blankets. Each solar blanket contains 82 PV panels. The PV power modules provide a 160 V nominal operating voltage. Previous research has shown that there are electrical interactions between a plasma environment and a photovoltaic power source. The interactions take two forms: parasitic current loss (occurs when the currect produced by the PV panel leaves at a high potential point and travels through the plasma to a lower potential point, effectively shorting that portion of the PV panel); and arcing (occurs when the PV panel electrically discharges into the plasma). The PV solar array panel plasma interaction test was conceived to evaluate the effects of these interactions on the Space Station Freedom type PV panels as well as to conduct further research. The test article consists of two active solar array panels in series. Each panel consists of two hundred 8 cm x 8 cm silicon solar cells. The test requirements dictated specifications in the following areas: plasma environment/plasma sheath; outgassing; thermal requirements; solar simulation; and data collection requirements.

  7. Solar terrestrial coupling through space plasma processes

    Energy Technology Data Exchange (ETDEWEB)

    Birn, J. [and others

    2000-12-01

    This is the final report of a three-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The project investigates plasma processes that govern the interaction between the solar wind, charged particles ejected from the sun, and the earth's magnetosphere, the region above the ionosphere governed by the terrestrial magnetic field. Primary regions of interest are the regions where different plasma populations interact with each other. These are regions of particularly dynamic plasma behavior, associated with magnetic flux and energy transfer and dynamic energy release. The investigations concerned charged particle transport and energization, and microscopic and macroscopic instabilities in the magnetosphere and adjacent regions. The approaches combined space data analysis with theory and computer simulations.

  8. Plasma and Field Boundaries in Space

    Science.gov (United States)

    Sonnerup, B. U.

    2010-12-01

    Many of the most important and intriguing phenomena in a space plasma occur at the boundaries between regions containing plasmas of different thermodynamic and flow properties, and different magnetization. In this lecture, I will describe and discuss a few of the observed effects and their proposed interpretations, with emphasis on the earth’s magnetopause as well as on certain magnetic discontinuities and structures seen in the solar wind. Among the physical phenomena is magnetic reconnection and associated current filamentation, as well as Kelvin-Helmholtz instability and waves. A primary tool for the illustration and interpretation of local structure within and near these boundaries will be reconstruction based on various versions of the MHD equations. These new methods produce field/flow maps in two dimensions of a narrow region of space surrounding the path of an observing spacecraft as it passes through the structure.

  9. Extraordinary Matter: Visualizing Space Plasmas and Particles

    Science.gov (United States)

    Barbier, S. B.; Bartolone, L.; Christian, E.; Thieman, J.; Eastman, T.; Lewis, E.

    2011-09-01

    Atoms and sub-atomic particles play a crucial role in the dynamics of our universe, but these particles and the space plasmas comprised of them are often overlooked in popular scientific and educational resources. Although the concepts are pertinent to a wide range of topics, even the most basic particle and plasma physics principles are generally unfamiliar to non-scientists. Educators and public communicators need assistance in explaining these concepts that cannot be easily demonstrated in the everyday world. Active visuals are a highly effective aid to understanding, but resources of this type are currently few in number and difficult to find, and most do not provide suitable context for audience comprehension. To address this need, our team is developing an online multimedia reference library of animations, visualizations, interactivities, and videos resources - Extraordinary Matter: Visualizing Space Plasmas and Particles. The site targets grades 9-14 and the equivalent in informal education and public outreach. Each ready-to-use product will be accompanied by a supporting explanation at a reading level matching the educational level of the concept. It will also have information on relevant science, technology, engineering, and mathematics (STEM) educational standards, activities, lesson plans, related products, links, and suggested uses. These products are intended to stand alone, making them adaptable to the widest range of uses, including scientist presentations, museum displays, educational websites and CDs, teacher professional development, and classroom use. This project is funded by a NASA Education and Public Outreach in Earth and Space Science (EPOESS) grant.

  10. Space as an open plasma laboratory

    Science.gov (United States)

    Papadopoulos, Konstantinos

    2011-10-01

    Ionospheric heaters supplemented by ground and space based diagnostic instruments have for a long time being used to conduct plasma physics, geophysical and radio science investigations. The recently completed HF transmitter associated with the High Frequency Active Ionospheric Research Program (HAARP), far exceeds the capabilities of previous ionospheric heaters and allows for new frontier research in plasma physics, geophysics and radio science. The transmitter radiates 3.6 MW of HF power in the 2.8-10.0 MHz frequency range. The beam-width varies from 15-5 degrees, corresponding to 20-30 dB gain and resulting in Effective Radiating Power (ERP) between.36-4.0 GW. The antenna can point to any direction in a cone of 30 degrees from the vertical, with a reposition time of 15 degrees in 15 microseconds resulting in super-luminous scanning speeds. The transmitter can synthesize essentially any desired waveform in linear and circular polarization. We present a number of HAARP experiments that used space as an open plasma laboratory. The experiments cover the areas of (i) Artificial ULF/ELF/VLF generation and injection in the magnetosphere (ii) Studies of wave-particle interactions in the magnetosphere (iii) Langmuir turbulence, parametric instabilities, electron acceleration and optical emissions (iv) Artificial ionization. Ionospheric heaters supplemented by ground and space based diagnostic instruments have for a long time being used to conduct plasma physics, geophysical and radio science investigations. The recently completed HF transmitter associated with the High Frequency Active Ionospheric Research Program (HAARP), far exceeds the capabilities of previous ionospheric heaters and allows for new frontier research in plasma physics, geophysics and radio science. The transmitter radiates 3.6 MW of HF power in the 2.8-10.0 MHz frequency range. The beam-width varies from 15-5 degrees, corresponding to 20-30 dB gain and resulting in Effective Radiating Power (ERP

  11. Negative plasma potential relative to electron-emitting surfaces.

    Science.gov (United States)

    Campanell, M D

    2013-09-01

    Most works on plasma-wall interaction predict that with strong electron emission, a nonmonotonic "space-charge-limited" (SCL) sheath forms where the plasma potential is positive relative to the wall. We show that a fundamentally different sheath structure is possible where the potential monotonically increases toward a positively charged wall that is shielded by a single layer of negative charge. No ion-accelerating presheath exists in the plasma and the ion wall flux is zero. An analytical solution of the "inverse sheath" regime is demonstrated for a general plasma-wall system where the plasma electrons and emitted electrons are Maxwellian with different temperatures. Implications of the inverse sheath effect are that (a) the plasma potential is negative, (b) ion sputtering vanishes, (c) no charge is lost at the wall, and (d) the electron energy flux is thermal. To test empirically what type of sheath structure forms under strong emission, a full plasma bounded by strongly emitting walls is simulated. It is found that inverse sheaths form at the walls and ions are confined in the plasma. This result differs from past particle-in-cell simulation studies of emission which contain an artificial "source sheath" that accelerates ions to the wall, leading to a SCL sheath at high emission intensity.

  12. Computerized tomographic imaging for space plasma physics

    Science.gov (United States)

    Zhang, Yuhong; Coplan, Michael A.; Moore, John H.; Berenstein, Carlos A.

    1990-01-01

    The measurement of plasma electron velocity distribution functions as a problem in imaging and image reconstruction is considered. A model instrument that measures the integral of the distribution function along lines in velocity space is presented. This allows the use of the powerful mathematical and numerical methods that have recently been so successful in other areas of imaging. It is found that this approach leads to classes of instruments that are qualitatively different from contemporary designs. An investigation of different methods of reconstruction of the distribution function from integral measurements reveals that the mathematical tools appropriate to one particular imaging problem may be very different from those required to deal with another.

  13. SNS potential with exchange field in quantum dusty plasmas

    Science.gov (United States)

    Zeba, I.; Batool, Maryam; Khan, Arroj A.; Jamil, M.; Rozina, Ch

    2017-02-01

    The shielding potential of a static test charge is studied in quantum dusty plasmas. The plasma system consisting upon electrons, ions and negatively static charged dust species, is embedded in an ambient magnetic field. The modified equation of dispersion is derived using quantum hydrodynamic model (QHD) for magnetized plasmas. The quantum effects are inculcated through Fermi degenerate pressure, tunneling effect and exchange-correlation effects. The study of shielding is important to know the existence of the silence zones in space and astrophysical objects as well as crystal formation. The graphical description of the normalized potential depict the significance of the exchange and correlation effects arising through spin and other variables on the shielding potential.

  14. The expansion of a plasma into a vacuum - Basic phenomena and processes and applications to space plasma physics

    Science.gov (United States)

    Wright, K. H., Jr.; Stone, N. H.; Samir, U.

    1983-01-01

    In this review attention is called to basic phenomena and physical processes involved in the expansion of a plasma into a vacuum, or the expansion of a plasma into a more tenuous plasma, in particular the fact that upon the expansion, ions are accelerated and reach energies well above their thermal energy. Also, in the process of the expansion a rarefaction wave propagates into the ambient plasma, an ion front moves into the expansion volume, and discontinuities in plasma parameters occur. The physical processes which cause the above phenomena are discussed, and their possible application is suggested for the case of the distribution of ions and electrons (hence plasma potential and electric fields) in the wake region behind artificial and natural obstacles moving supersonically in a rarefied space plasma. To illustrate this, some in situ results are reexamined. Directions for future work in this area via the utilization of the Space Shuttle and laboratory work are also mentioned.

  15. NASA/Marshall Space Flight Center's Contributions to Space Plasma Physics

    Science.gov (United States)

    Adrian, M. L.; Six, N. Frank (Technical Monitor)

    2002-01-01

    Since the mid-l970's, the Space Plasma Physics Group at NASA's Marshall Space Flight Center has contributed critical instrumentation to numerous satellite and sounding rocket missions exploring the plasmas of near-Earth space. This talk will review major discoveries in Earth's ionosphere, plasmasphere, and magnetosphere directly attributable to the researchers of the Space Plasma Physics Group and the significance of these discoveries to the field of plasma physics.

  16. The Potential for Ambient Plasma Wave Propulsion

    Science.gov (United States)

    Gilland, James H.; Williams, George J.

    2016-01-01

    A truly robust space exploration program will need to make use of in-situ resources as much as possible to make the endeavor affordable. Most space propulsion concepts are saddled with one fundamental burden; the propellant needed to produce momentum. The most advanced propulsion systems currently in use utilize electric and/or magnetic fields to accelerate ionized propellant. However, significant planetary exploration missions in the coming decades, such as the now canceled Jupiter Icy Moons Orbiter, are restricted by propellant mass and propulsion system lifetimes, using even the most optimistic projections of performance. These electric propulsion vehicles are inherently limited in flexibility at their final destination, due to propulsion system wear, propellant requirements, and the relatively low acceleration of the vehicle. A few concepts are able to utilize the environment around them to produce thrust: Solar or magnetic sails and, with certain restrictions, electrodynamic tethers. These concepts focus primarily on using the solar wind or ambient magnetic fields to generate thrust. Technically immature, quasi-propellantless alternatives lack either the sensitivity or the power to provide significant maneuvering. An additional resource to be considered is the ambient plasma and magnetic fields in solar and planetary magnetospheres. These environments, such as those around the Sun or Jupiter, have been shown to host a variety of plasma waves. Plasma wave propulsion takes advantage of an observed astrophysical and terrestrial phenomenon: Alfven waves. These are waves that propagate in the plasma and magnetic fields around and between planets and stars. The generation of Alfven waves in ambient magnetic and plasma fields to generate thrust is proposed as a truly propellantless propulsion system which may enable an entirely new matrix of exploration missions. Alfven waves are well known, transverse electromagnetic waves that propagate in magnetized plasmas at

  17. Space weather circulation model of plasma clouds as background radiation medium of space environment.

    Science.gov (United States)

    Kalu, A. E.

    A model for Space Weather (SW) Circulation with Plasma Clouds as background radiation medium of Space Environment has been proposed and discussed. Major characteristics of the model are outlined and the model assumes a baroclinic Space Environment in view of observed pronounced horizontal electron temperature gradient with prevailing weak vertical temperature gradient. The primary objective of the study is to be able to monitor and realistically predict on real- or near real-time SW and Space Storms (SWS) affecting human economic systems on Earth as well as the safety and Physiologic comfort of human payload in Space Environment in relation to planned increase in human space flights especially with reference to the ISS Space Shuttle Taxi (ISST) Programme and other prolonged deep Space Missions. Although considerable discussions are now available in the literature on SW issues, routine Meteorological operational applications of SW forecast data and information for Space Environment are still yet to receive adequate attention. The paper attempts to fill this gap in the literature of SW. The paper examines the sensitivity and variability in 3-D continuum of Plasmas in response to solar radiation inputs into the magnetosphere under disturbed Sun condition. Specifically, the presence of plasma clouds in the form of Coronal Mass Ejections (CMEs) is stressed as a major source of danger to Space crews, spacecraft instrumentation and architecture charging problems as well as impacts on numerous radiation - sensitive human economic systems on Earth. Finally, the paper considers the application of model results in the form of effective monitoring of each of the two major phases of manned Spaceflights - take-off and re-entry phases where all-time assessment of spacecraft transient ambient micro-incabin and outside Space Environment is vital for all manned Spaceflights as recently evidenced by the loss of vital information during take-off of the February 1, 2003 US Columbia

  18. Complex and Dusty Plasmas From Laboratory to Space

    CERN Document Server

    Fortov, Vladimir E

    2009-01-01

    Dusty or complex plasmas are plasmas containing solid or liquid charged particles referred to as dust. Naturally occurring in space, on earth dust plays a key role in plasma applications associated with etching technologies in microelectronics. International in scope, this volume covers theoretical and application research.

  19. Laser-plasma-based Space Radiation Reproduction in the Laboratory

    Science.gov (United States)

    Hidding, B.; Karger, O.; Königstein, T.; Pretzler, G.; Manahan, G. G.; McKenna, P.; Gray, R.; Wilson, R.; Wiggins, S. M.; Welsh, G. H.; Beaton, A.; Delinikolas, P.; Jaroszynski, D. A.; Rosenzweig, J. B.; Karmakar, A.; Ferlet-Cavrois, V.; Costantino, A.; Muschitiello, M.; Daly, E.

    2017-01-01

    Space radiation is a great danger to electronics and astronauts onboard space vessels. The spectral flux of space electrons, protons and ions for example in the radiation belts is inherently broadband, but this is a feature hard to mimic with conventional radiation sources. Using laser-plasma-accelerators, we reproduced relativistic, broadband radiation belt flux in the laboratory, and used this man-made space radiation to test the radiation hardness of space electronics. Such close mimicking of space radiation in the lab builds on the inherent ability of laser-plasma-accelerators to directly produce broadband Maxwellian-type particle flux, akin to conditions in space. In combination with the established sources, utilisation of the growing number of ever more potent laser-plasma-accelerator facilities worldwide as complementary space radiation sources can help alleviate the shortage of available beamtime and may allow for development of advanced test procedures, paving the way towards higher reliability of space missions. PMID:28176862

  20. Laser-plasma-based Space Radiation Reproduction in the Laboratory.

    Science.gov (United States)

    Hidding, B; Karger, O; Königstein, T; Pretzler, G; Manahan, G G; McKenna, P; Gray, R; Wilson, R; Wiggins, S M; Welsh, G H; Beaton, A; Delinikolas, P; Jaroszynski, D A; Rosenzweig, J B; Karmakar, A; Ferlet-Cavrois, V; Costantino, A; Muschitiello, M; Daly, E

    2017-02-08

    Space radiation is a great danger to electronics and astronauts onboard space vessels. The spectral flux of space electrons, protons and ions for example in the radiation belts is inherently broadband, but this is a feature hard to mimic with conventional radiation sources. Using laser-plasma-accelerators, we reproduced relativistic, broadband radiation belt flux in the laboratory, and used this man-made space radiation to test the radiation hardness of space electronics. Such close mimicking of space radiation in the lab builds on the inherent ability of laser-plasma-accelerators to directly produce broadband Maxwellian-type particle flux, akin to conditions in space. In combination with the established sources, utilisation of the growing number of ever more potent laser-plasma-accelerator facilities worldwide as complementary space radiation sources can help alleviate the shortage of available beamtime and may allow for development of advanced test procedures, paving the way towards higher reliability of space missions.

  1. Separable Dual Space Gaussian Pseudo-potentials

    CERN Document Server

    Gödecker, S; Hutter, J

    1995-01-01

    We present pseudo-potential coefficients for the first two rows of the periodic table. The pseudo potential is of a novel analytic form, that gives optimal efficiency in numerical calculations using plane waves as basis set. At most 7 coefficients are necessary to specify its analytic form. It is separable and has optimal decay properties in both real and Fourier space. Because of this property, the application of the nonlocal part of the pseudo-potential to a wave-function can be done in an efficient way on a grid in real space. Real space integration is much faster for large systems than ordinary multiplication in Fourier space since it shows only quadratic scaling with respect to the size of the system. We systematically verify the high accuracy of these pseudo-potentials by extensive atomic and molecular test calculations.

  2. Origins and properties of kappa distributions in space plasmas

    Science.gov (United States)

    Livadiotis, George

    2016-07-01

    Classical particle systems reside at thermal equilibrium with their velocity distribution function stabilized into a Maxwell distribution. On the contrary, collisionless and correlated particle systems, such as the space and astrophysical plasmas, are characterized by a non-Maxwellian behavior, typically described by the so-called kappa distributions. Empirical kappa distributions have become increasingly widespread across space and plasma physics. However, a breakthrough in the field came with the connection of kappa distributions to the solid statistical framework of Tsallis non-extensive statistical mechanics. Understanding the statistical origin of kappa distributions was the cornerstone of further theoretical developments and applications, some of which will be presented in this talk: (i) The physical meaning of thermal parameters, e.g., temperature and kappa index; (ii) the multi-particle description of kappa distributions; (iii) the phase-space kappa distribution of a Hamiltonian with non-zero potential; (iv) the Sackur-Tetrode entropy for kappa distributions, and (v) the new quantization constant, h _{*}˜10 ^{-22} Js.

  3. Potential Barrier around an Emitting Body an a Plasma

    Science.gov (United States)

    Bruno, Antonio; Luca Delzanno, Gian; Sorasio, Gianfranco; Lapenta, Giovanni

    2005-10-01

    We present a self-consistent, kinetic theory for the charging and shielding of an object at rest in a collisionless plasma [1]. The body is an electron emitter according to thermionic emission, photoemission or secondary emission. The theory is formulated for positively charged bodies, derived under the assumption of spherical symmetry so that conservation of energy and angular momentum can be used to calculate the plasma distribution functions at any given point in phase space. Far away from the body the plasma is assumed unperturbed, described by a Maxwellian distribution function at rest. Thus, the unperturbed plasma acts as a source of particles balancing the absorptions from the body and a steady state is eventually reached. The theory is shown to be in good agreement with PIC simulations [1-2]. Further on, several cases (focusing on parameters typical of laboratory experiments) are presented for the three different emission mechanisms, showing that shielding potentials having an attractive well are possible for all of them.[1] G. L. Delzanno, A. Bruno, G. Sorasio, G. Lapenta, Phys. Plasmas 12, 062102 (2005).[2] G. L. Delzanno, G. Lapenta, M. Rosenberg, Phys. Rev. Lett. 92 (3), 035002 (2004).

  4. ISS And Space Environment Interactions Without Operating Plasma Contactor

    Science.gov (United States)

    Carruth, M. R., Jr.; Ferguson, Dale; Suggs,Rob; McCollum, Matt

    2001-01-01

    The International Space Station (ISS) will be the largest, highest power spacecraft placed in orbit. Because of this the design of the electrical power system diverged markedly from previous systems. The solar arrays will operate at 160 V and the power distribution voltage will be 120 V. The structure is grounded to the negative side of the solar arrays so under the right circumstances it is possible to drive the ISS potential very negative. A plasma contactor has been added to the ISS to provide control of the ISS structure potential relative to the ambient plasma. The ISS requirement is that the ISS structure not be greater than 40 V positive or negative of local plasma. What are the ramifications of operating large structures with such high voltage power systems? The application of a plasma contactor on ISS controls the potential between the structure and the local plasma, preventing degrading effects. It is conceivable that there can be situations where the plasma contactor might be non-functional. This might be due to lack of power, the need to turn it off during some of the build-up sequences, the loss of functionality for both plasma contactors before a replacement can be installed, similar circumstances. A study was undertaken to understand how important it is to have the contactor functioning and how long it might be off before unacceptable degradation to ISS could occur. The details of interaction effects on spacecraft have not been addressed until driven by design. This was true for ISS. If the structure is allowed to float highly negative impinging ions can sputter exposed conductors which can degrade the primary surface and also generate contamination due to the sputtered material. Arcing has been known to occur on solar arrays that float negative of the ambient plasma. This can also generate electromagnetic interference and voltage transients. Much of the ISS structure and pressure module surfaces exposed to space is anodized aluminum. The anodization

  5. Plasma Hazards and Acceptance for International Space Station Extravehicular Activities

    Science.gov (United States)

    Patton, Thomas

    2010-09-01

    Extravehicular activity(EVA) is accepted by NASA and other space faring agencies as a necessary risk in order to build and maintain a safe and efficient laboratory in space. EVAs are used for standard construction and as contingency operations to repair critical equipment for vehicle sustainability and safety of the entire crew in the habitable volume. There are many hazards that are assessed for even the most mundane EVA for astronauts, and the vast majority of these are adequately controlled per the rules of the International Space Station Program. The need for EVA repair and construction has driven acceptance of a possible catastrophic hazard to the EVA crewmember which cannot currently be controlled adequately. That hazard is electrical shock from the very environment in which they work. This paper describes the environment, causes and contributors to the shock of EVA crewmembers attributed to the ionospheric plasma environment in low Earth orbit. It will detail the hazard history, and acceptance process for the risk associated with these hazards that give assurance to a safe EVA. In addition to the hazard acceptance process this paper will explore other factors that go into the decision to accept a risk including criticality of task, hardware design and capability, and the probability of hazard occurrence. Also included will be the required interaction between organizations at NASA(EVA Office, Environments, Engineering, Mission Operations, Safety) in order to build and eventually gain adequate acceptance rationale for a hazard of this kind. During the course of the discussion, all current methods of mitigating the hazard will be identified. This paper will capture the history of the plasma hazard analysis and processes used by the International Space Station Program to formally assess and qualify the risk. The paper will discuss steps that have been taken to identify and perform required analysis of the floating potential shock hazard from the ISS environment

  6. Characteristics and potential applications of an ORNL microwave ECR multicusp plasma ion source

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, C.C.

    1990-01-01

    A new microwave electron cyclotron resonance (ECR) multicusp plasma ion source that has two ECR plasma production regions and uses multicusp plasma confinement has been developed at Oak Ridge National Laboratory. This source has been operated to produce uniform and dense plasma over large areas of 300 to 400 cm{sup 2} and could be scaled up to produce uniform plasma over 700 cm{sup 2} or larger. The plasma source has been operated with continuous argon gas feed and pulsed microwave power. The working gases used were argon, helium, hydrogen, and oxygen. The discharge initiation phenomena and plasma properties have been investigated and studied as functions of the discharge parameters. The discharge characteristics and a hypothetical discharge mechanism for this plasma source are described and discussed. Potential applications, including plasma and ion-beam sources for manufacturing advanced microelectronics, for space electric propulsion, and for fusion research, are discussed. 10 refs., 10 figs.

  7. Introduction to plasma physics with space, laboratory and astrophysical applications

    CERN Document Server

    Gurnett, Donald A

    2017-01-01

    Introducing basic principles of plasma physics and their applications to space, laboratory and astrophysical plasmas, this new edition provides updated material throughout. Topics covered include single-particle motions, kinetic theory, magnetohydrodynamics, small amplitude waves in hot and cold plasmas, and collisional effects. New additions include the ponderomotive force, tearing instabilities in resistive plasmas and the magnetorotational instability in accretion disks, charged particle acceleration by shocks, and a more in-depth look at nonlinear phenomena. A broad range of applications are explored: planetary magnetospheres and radiation belts, the confinement and stability of plasmas in fusion devices, the propagation of discontinuities and shock waves in the solar wind, and analysis of various types of plasma waves and instabilities that can occur in planetary magnetospheres and laboratory plasma devices. With step-by-step derivations and self-contained introductions to mathematical methods, this book...

  8. Bessel potential space on the Laguerre hypergroup

    Directory of Open Access Journals (Sweden)

    Ahmed Taieb

    2011-01-01

    Full Text Available Abstract In this article, we define the fractional differentiation Dδ of order δ, δ > 0, induced by the Laguerre operator L and associated with respect to the Haar measure dmα. We obtain a characterization of the Bessel potential space using Dδ and different equivalent norms.

  9. Plasma Liner Research for MTF at NASA Marshall Space Flight Center

    Science.gov (United States)

    Thio, Y. C. F.; Eskridge, R.; Lee, M.; Martin, A.; Smith, J.; Cassibry, J. T.; Wu, S. T.; Kirkpatrick, R. C.; Knapp, C. E.; Turchi, P. J.; Rodgers, Stephen L. (Technical Monitor)

    2002-01-01

    The current research effort at NASA Marshall Space Flight Center (MSFC) in MTF is directed towards exploring the critical physics issues of potential embodiments of MTF for propulsion, especially standoff drivers involving plasma liners for MTF. There are several possible approaches for forming plasma liners. One approach consists of using a spherical array of plasma jets to form a spherical plasma shell imploding towards the center of a magnetized plasma, a compact toroid. Current experimental plan and status to explore the physics of forming a 2-D plasma liner (shell) by merging plasma jets are described. A first-generation coaxial plasma guns (Mark-1) to launch the required plasma jets have been built and tested. Plasma jets have been launched reproducibly with a low jitter, and velocities in excess of 50 km/s for the leading edge of the plasma jet. Some further refinements are being explored for the plasma gun, Successful completion of these single-gun tests will be followed by an experimental exploration of the problems of launching a multiple number of these jets simultaneously to form a cylindrical plasma liner.

  10. Kinetic Alfven wave turbulence in space plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, R.P. [Plasma Simulation Laboratory, Centre for Energy Studies, Indian Institute of Technology, Delhi-110016, New Delhi (India); Kumar, Sachin, E-mail: dynamicalfven@gmail.co [Plasma Simulation Laboratory, Centre for Energy Studies, Indian Institute of Technology, Delhi-110016, New Delhi (India)

    2010-07-26

    This work presents the derivation of nonlinear coupled equations for the evolution of solar wind turbulence. These equations are governing the coupled dynamics of kinetic Alfven wave and ion acoustic wave. Numerical simulation of these equations is also presented. The ponderomotive nonlinearity is incorporated in the wave dynamics. Filamentation of kinetic Alfven wave and the turbulent spectra are presented in intermediate-{beta} plasmas at heliocentric distances (0.3 AU{<=}r<1.0 AU). The growing filaments and steeper turbulent spectra (of power law k{sup -S}, 5/3{<=}S{<=}3) can be responsible for plasma heating and particle acceleration in solar wind.

  11. Study of the interaction between space plasma and high voltage solar array

    OpenAIRE

    Iwasa, Minoru; TANAKA, KOJI; Sasaki, Susumu; ODAWARA, OSAMU; 岩佐 稔; 田中 孝治; 佐々木 進; 小田原 修

    2006-01-01

    We are studying the problems associated with high voltage power systems in space. Especially we are interested in the potential distribution of the solar array that is resistant to the electrical discharge. We have carried out experiment on the interaction between the space plasma and the high voltage solar array. An array of electrodes distributed on a dielectric material was used to simulate the inter-connectors of the solar array panel in space environment. One of major concerns in the usa...

  12. On Improving Impedance Probe Plasma Potential Measurements

    Science.gov (United States)

    2014-02-21

    assumption of a collisionless, stationary Maxwellian plasma and are seen to work well in non -flowing plasmas of sufficient density. However, as plasma...collection area. For Maxwellian electrons, np = n exp(Vp-φp)/Te and so at low frequency from Eq. (1) above, the resistive component of the ac

  13. Ionosphere Plasma State Determination in Low Earth Orbit from International Space Station Plasma Monitor

    Science.gov (United States)

    Kramer, Leonard

    2014-01-01

    A plasma diagnostic package is deployed on the International Space Station (ISS). The system - a Floating Potential Measurement Unit (FPMU) - is used by NASA to monitor the electrical floating potential of the vehicle to assure astronaut safety during extravehicular activity. However, data from the unit also reflects the ionosphere state and seems to represent an unutilized scientific resource in the form of an archive of scientific plasma state data. The unit comprises a Floating Potential probe and two Langmuir probes. There is also an unused but active plasma impedance probe. The data, at one second cadence, are collected, typically for a two week period surrounding extravehicular activity events. Data is also collected any time a visiting vehicle docks with ISS and also when any large solar events occur. The telemetry system is unusual because the package is mounted on a television camera stanchion and its data is impressed on a video signal that is transmitted to the ground and streamed by internet to two off center laboratory locations. The data quality has in the past been challenged by weaknesses in the integrated ground station and distribution systems. These issues, since mid-2010, have been largely resolved and the ground stations have been upgraded. Downstream data reduction has been developed using physics based modeling of the electron and ion collecting character in the plasma. Recursive algorithms determine plasma density and temperature from the raw Langmuir probe current voltage sweeps and this is made available in real time for situational awareness. The purpose of this paper is to describe and record the algorithm for data reduction and to show that the Floating probe and Langmuir probes are capable of providing long term plasma state measurement in the ionosphere. Geophysical features such as the Appleton anomaly and high latitude modulation at the edge of the Auroral zones are regularly observed in the nearly circular, 51 deg inclined, 400 km

  14. EDITORIAL: Interrelationship between plasma phenomena in the laboratory and in space

    Science.gov (United States)

    Koepke, Mark

    2008-07-01

    relevant physics within these ranges and extrapolate the results to space conditions that may or may not be subject to any restrictions on the values of the plasma parameters. The interrelationship between laboratory and space plasma experiments has been cultivated at a low level and the potential scientific benefit in this area has yet to be realized. The few but excellent examples of joint papers, joint experiments, and directly relevant cross-disciplinary citations are a direct result of the emphasis placed on this interrelationship two decades ago. Building on this special issue Plasma Physics and Controlled Fusion plans to create a dedicated webpage to highlight papers directly relevant to this field published either in the recent past or in the future. It is hoped that this resource will appeal to the readership in the laboratory-experiment and space-plasma communities and improve the cross-fertilization between them.

  15. Potential applications of a new microwave ECR (electron cyclotron resonance) multicusp plasma ion source

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, C.C.

    1990-01-01

    A new microwave electron cyclotron resonance (ECR) multicusp plasma ion source using two ECR plasma production regions and multicusp plasma confinement has been developed at Oak Ridge National Laboratory. This source has been operated to produce uniform and dense plasmas over large areas of 300 to 400 cm{sup 2}. The plasma source has been operated with continuous argon gas feed and pulsed microwave power. The discharge initiation phenomena and plasma properties have been investigated and studied as functions of discharge parameters. Together with the discharge characteristics observed, a hypothetical discharge mechanism for this plasma source is reported and discussed. Potential applications, including plasma and ion-beam processing for manufacturing advanced microelectronics and for space electric propulsion, are discussed. 7 refs., 6 figs.

  16. Potential applications of a new microwave ECR multicusp plasma ion source

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, C.C. (Fusion Energy Div., Oak Ridge National Lab., TN (USA))

    1991-05-01

    A new microwave electron cyclotron resonance (ECR) multicusp plasma ion source using two ECR plasma production regions and multicusp plasma confinement has been developed at Oak Ridge National Laboratory. This source has been operated to produce uniform and dense plasmas over large areas of 300-400 cm{sup 2}. The plasma source has been operated with continuous argon gas feed and pulsed microwave power. The discharge initiation phenomena and plasma properties have been investigated and studied as functions of discharge parameters. Together with the discharge characteristics observed, a hypothetical discharge mechanism for this plasma source is reported and discussed. Potential applications, including plasma and ion-beam processing for manufacturing advanced microelectronics and for space electric propulsion, are discussed. (orig.).

  17. On the dynamics of space plasma

    Science.gov (United States)

    Albert, Jay; Chan, Chung; Silevitch, Michael; Villalon, Elena

    1992-09-01

    The research was focused into three related areas. These were: (1) an examination of stochastic electron acceleration mechanisms in the ionosphere and the resulting dynamics of magnetospheric (i.e., Radiation Belt) particles and waves; (2) a study of nonadiabatic particle orbits and the electrodynamic structure of the coupled magnetosphere-ionosphere auroral arc system; (3) an experimental investigation of the wake signatures created by a solid body immersed in a flowing plasma.

  18. Space and Astrophysical Plasmas : Ionospheric plasma by VHF waves

    Indian Academy of Sciences (India)

    R P Patel; Abhay Kumar Singh; R P Singh

    2000-11-01

    The amplitude scintillations of very high frequency electromagnetic wave transmitted from geo-stationary satellite at 244.168 MHz have been recorded at Varanasi (geom. lat. 14° 55'N) during 1991 to 1999. The data are analyzed to determine the statistical features of overhead ionospheric plasma irregularities which are mostly of small duration < 30 minutes and are predominant during pre-midnight period. The increase of solar activity generally increases the depth of scintillation. The auto-correlation functions and power spectra of scintillations predict that the scale length of these irregularities varies from 200–500 m having velocity of movement between 75 m/sec to 200 m/sec. These results agree well with the results obtained by other workers.

  19. Parameters influencing plasma column potential in a reflex discharge

    Science.gov (United States)

    Liziakin, G. D.; Gavrikov, A. V.; Murzaev, Y. A.; Usmanov, R. A.; Smirnov, V. P.

    2016-12-01

    Distribution of electrostatic potential in direct current reflex discharge plasma has been studied experimentally. Measurements have been conducted by the single floating probe method. The influence of 0-0.2 T magnetic field, 1-200 mTorr pressure, 0-2 kV discharge voltage, and electrodes geometry on plasma column electrostatic potential was investigated. The possibility for the formation of a preset potential profile required for the realization of plasma separation of spent nuclear fuel was demonstrated.

  20. Using Space as a Nonlinear Plasma Laboratory

    Science.gov (United States)

    Papadopoulos, Konstantinos

    2008-11-01

    Ionospheric heaters have been an important tool of plasma physics investigations. The extent that non-linear plasma phenomena can be triggered and observed depends critically on the heater power, its Effective Radiative Power (ERP) and its scanning capability. Increasing these parameters allows us to reach thresholds associated with effects that were not previously observed. The latest entry to ionospheric heating, the HF transmitter associated with the High Frequency Active Ionospheric Research Program (HAARP) was completed in June 2007. The transmitter consists of 180 antenna elements spanning 30.6 acres and can radiate 3.6 MW of HF power (a factor of almost 4 higher than any previous heater) in the 2.8-10.0 MHz range. With increasing frequency the beam-width varies from 15-5 degrees, corresponding to 20-30 dB gain and resulting in ERP between 1-5 GW. The antenna can point to any direction in a cone 30 degrees from the vertical, with reposition time of 15 microseconds resulting in superluminal scanning speeds. The transmitter can synthesize essentially any waveform and transmit any polarization. These capabilities far exceed those of any previous heater and allow for new frontier research in non-linear plasma physics. The presentation will focus first on the relationship of the new capabilities of the facility with thresholds of physical processes that had not been achieved previously. It will then present new spectacular results that have been achieved during the last year. They include whistler injection and amplification, injection of shear and magnetosonic waves in the magnetosphere, Langmuir turbulence, upper hybrid waves and thermal instabilities, electron acceleration, optical emissions and formation of artificial ducts for whistler propagation. The presentation will also discuss future experiments made possible for the first time by the new transmitter capabilities, large bandwidth and high ERP.

  1. Driven phase space vortices in plasmas with nonextensive velocity distribution

    Science.gov (United States)

    Trivedi, Pallavi; Ganesh, Rajaraman

    2017-03-01

    The evolution of chirp-driven electrostatic waves in unmagnetized plasmas is numerically investigated by using a one-dimensional (1D) Vlasov-poisson solver with periodic boundary conditions. The initial velocity distribution of the 1D plasma is assumed to be governed by nonextensive q distribution [C. Tsallis, J. Stat. Phys. 52, 479 (1988)]. For an infinitesimal amplitude of an external drive, we investigate the effects of chirp driven dynamics that leads to the formation of giant phase space vortices (PSV) for both Maxwellian (q = 1) and non-Maxwellian ( q ≠ 1 ) plasmas. For non-Maxwellian plasmas, the formation of giant PSV with multiple extrema and phase velocities is shown to be dependent on the strength of "q". Novel features such as "shark"-like and transient "honeycomb"-like structures in phase space are discussed. Wherever relevant, we compare our results with previous work.

  2. Laser Diagnostic Method for Plasma Sheath Potential Mapping

    Science.gov (United States)

    Walsh, Sean P.

    Electric propulsion systems are gaining popularity in the aerospace field as a viable option for long term positioning and thrusting applications. In particular, Hall thrusters have shown promise as the primary propulsion engine for space probes during interplanetary journeys. However, the interaction between propellant xenon ions and the ceramic channel wall continues to remain a complex issue. The most significant source of power loss in Hall thrusters is due to electron and ion currents through the sheath to the channel wall. A sheath is a region of high electric field that separates a plasma from a wall or surface in contact. Plasma electrons with enough energy to penetrate the sheath may result emission of a secondary electron from the wall. With significant secondary electron emission (SEE), the sheath voltage is reduced and so too is the electron retarding electric field. Therefore, a lower sheath voltage further increases the particle loss to the wall of a Hall thruster and leads to plasma cooling and lower efficiency. To further understand sheath dynamics, laser-induced fluorescence is employed to provide a non-invasive, in situ, and spatially resolved technique for measuring xenon ion velocity. By scanning the laser wavelength over an electronic transition of singly ionized xenon and collecting the resulting fluorescence, one can determine the ion velocity from the Doppler shifted absorption. Knowing the velocity at multiple points in the sheath, it can be converted to a relative electric potential profile which can reveal a lot about the plasma-wall interaction and the severity of SEE. The challenge of adequately measuring sheath potential profiles is optimizing the experiment to maximize the signal-to-noise ratio. A strong signal with low noise, enables high resolution measurements and increases the depth of measurement in the sheath, where the signal strength is lowest. Many improvements were made to reduce the background luminosity, increase the

  3. A space-charge-neutralizing plasma for beam drift compression

    Science.gov (United States)

    Roy, P. K.; Seidl, P. A.; Anders, A.; Bieniosek, F. M.; Coleman, J. E.; Gilson, E. P.; Greenway, W.; Grote, D. P.; Jung, J. Y.; Leitner, M.; Lidia, S. M.; Logan, B. G.; Sefkow, A. B.; Waldron, W. L.; Welch, D. R.

    2009-07-01

    Simultaneous radial focusing and longitudinal compression of intense ion beams are being studied to heat matter to the warm dense matter, or strongly coupled plasma regime. Higher compression ratios can be achieved if the beam compression takes place in a plasma-filled drift region in which the space-charge forces of the ion beam are neutralized. Recently, a system of four cathodic arc plasma sources has been fabricated and the axial plasma density has been measured. A movable plasma probe array has been developed to measure the radial and axial plasma distribution inside and outside of a ˜10-cm-long final focus solenoid (FFS). Measured data show that the plasma forms a thin column of diameter ˜5 mm along the solenoid axis when the FFS is powered with an 8 T field. Measured plasma density of ⩾1×10 13 cm -3 meets the challenge of np/ Znb>1, where np and nb are the plasma and ion beam density, respectively, and Z is the mean ion charge state of the beam ions.

  4. Bending and Focusing with Plasmas and Crystals - Potential and Challenges

    CERN Document Server

    Zimmermann, F

    2013-01-01

    This talk review the potential of plasmas and crystals for focusing and bending high-energy charged particle beams. It covers topics like plasma lenses, plasma wigglers, plasma dipoles, crystal channeling & reflection, radiation in crystals, crystal accelerators, crystalline beams and ultimate limitations. Past, ongoing or required R&D efforts are highlighted. Invited presentation at EuCARD'13 "Visions for the Future of Particle Accelerators," CERN, 11 June 2013.

  5. Double Layers: Potential Formation and Related Nonlinear Phenomena in Plasmas: Proceedings of the 5th Symposium

    Science.gov (United States)

    Iizuka, S.

    1998-02-01

    The Table of Contents for the book is as follows: * PREFACE * INTERNATIONAL SCIENTIFIC COMMITTEE * LOCAL ORGANIZING COMMITTEE AT TOHOKU UNIVERSITY * CHAPTER 1: DOUBLE LAYERS, SHEATHS, AND POTENTIAL STRUCTURES * 1.1 Double Layers * On Fluid Models of Stationary, Acoustic Double Layers (Invited) * Particle Simulation of Double Layer (Invited) * Space-Time Dependence of Non-Steady Double Layers * The Role of Low Energy Electrons for the Generation of Anode Double Layers in Glow Discharges * Arbitrary Amplitude Ion-Acoustic Double Layers in a Dusty Plasma * 1.2 Sheaths * Bounded Plasma Edge Physics as Observed from Simulations in 1D and 2D (Invited) * Control of RF Sheath Structure in RF Diode Discharge * Observation of Density Gradients with Fine Structures and Low Frequency Wave Excitation at the Plasma-Sheath Boundary * Double Sheath Associated with an Electron Emission to a Plasma Containing Negative Ions * Sheath Edge and Floating Potential for Multi-Species Plasmas Including Dust Particles * 1.3 Potential Structures and Oscillations * Potential Structure Formed at a Constriction of a DC He Positive Column and its Coupling with Ionization Wave * Potential Structure in a New RF Magnetron Device with a Hollow Electrode * Potential Disruption in a RF Afterglow Electronegative Plasma * Potential Oscillation in a Strongly Asymmetry RF Discharge Containing Negative Ions * Effects of External Potential Control on Coulomb Dust Behavior * Potential Structure of Carbon Arc Discharge for High-Yield Fullerenes Formation * Control of Axial and Radial Potential Profiles in Tandem Mirrors (Invited) * CHAPTER 2: FIELD-ALIGNED ELECTRIC FIELDS AND RELATED PARTICLE ACCELERATIONS * 2.1 Field-Aligned Potential Formation * Formation of Large Potential Difference in a Plasma Flow along Converging Magnetic Field Lines (Invited) * Presheath Formation in front of an Oblique End-Plate in a Magnetized Sheet Plasma * Plasma Potential Formation Due to ECRH in a Magnetic Well * Electrostatic

  6. Space dusty plasmas: recent developments, advances, and unsolved problems

    Science.gov (United States)

    Popel, Sergey; Zelenyi, Lev

    2016-07-01

    The area of space dusty plasma research is a vibrant subfield of plasma physics that belongs to frontier research in physical sciences. This area is intrinsically interdisciplinary and encompasses astrophysics, planetary science, and atmospheric science. Dusty plasmas are ubiquitous in the universe; examples are proto-planetary and solar nebulae, molecular clouds, supernovae explosions, interplanetary medium, circumsolar rings, and asteroids. Within the solar system, we have planetary rings (e.g., Saturn and Jupiter), Martian atmosphere, cometary tails and comae, dust at the Moon, etc. Dust and dusty plasmas are also found in the vicinity of artificial satellites and space stations. The present review covers the main aspects of the area of space dusty plasma research. Emphasis is given to the description of dusty plasmas at the Moon which is important from the viewpoint of the future lunar missions and lunar observatory. This work was supported in part by the Presidium of the Russian Academy of Sciences (under Fundamental Research Program No. 7, "Experimental and Theoretical Study of the Solar System Objects and Stellar Planet Systems. Transient Explosion Processes in Astrophysics" and the Russian Foundation for Basic Research (Project No. 15-02-05627-a).

  7. Plasma Physics of the Subauroral Space Weather

    Science.gov (United States)

    2016-03-20

    observations near the magnetic equator and in the ionosphere, we specified their features and space weather effects. Near substorm onsets, highly...SAID events As the fast timescale is characteristic of propagation of substorm injection fronts, we focus on the observations near substorm onsets...magnetosphere data, respectively. The main initial tusk is to identify events near the magnetic equator following the onsets of substorms and Approved for

  8. Multipoint observations of plasma phenomena made in space by Cluster

    Science.gov (United States)

    Goldstein, M. L.; Escoubet, P.; Hwang, K.-Joo; Wendel, D. E.; Viñas, A.-F.; Fung, S. F.; Perri, S.; Servidio, S.; Pickett, J. S.; Parks, G. K.; Sahraoui, F.; Gurgiolo, C.; Matthaeus, W.; Weygand, J. M.

    2015-06-01

    Plasmas are ubiquitous in nature, surround our local geospace environment, and permeate the universe. Plasma phenomena in space give rise to energetic particles, the aurora, solar flares and coronal mass ejections, as well as many energetic phenomena in interstellar space. Although plasmas can be studied in laboratory settings, it is often difficult, if not impossible, to replicate the conditions (density, temperature, magnetic and electric fields, etc.) of space. Single-point space missions too numerous to list have described many properties of near-Earth and heliospheric plasmas as measured both in situ and remotely (see http://www.nasa.gov/missions/#.U1mcVmeweRY for a list of NASA-related missions). However, a full description of our plasma environment requires three-dimensional spatial measurements. Cluster is the first, and until data begin flowing from the Magnetospheric Multiscale Mission (MMS), the only mission designed to describe the three-dimensional spatial structure of plasma phenomena in geospace. In this paper, we concentrate on some of the many plasma phenomena that have been studied using data from Cluster. To date, there have been more than 2000 refereed papers published using Cluster data but in this paper we will, of necessity, refer to only a small fraction of the published work. We have focused on a few basic plasma phenomena, but, for example, have not dealt with most of the vast body of work describing dynamical phenomena in Earth's magnetosphere, including the dynamics of current sheets in Earth's magnetotail and the morphology of the dayside high latitude cusp. Several review articles and special publications are available that describe aspects of that research in detail and interested readers are referred to them (see for example, Escoubet et al. 2005 Multiscale Coupling of Sun-Earth Processes, p. 459, Keith et al. 2005 Sur. Geophys. 26, 307-339, Paschmann et al. 2005 Outer Magnetospheric Boundaries: Cluster Results, Space Sciences Series

  9. Kappa distributions: theory and applications in space plasmas

    CERN Document Server

    Pierrard, V

    2010-01-01

    Particle velocity distribution functions (VDF) in space plasmas often show non Maxwellian suprathermal tails decreasing as a power law of the velocity. Such distributions are well fitted by the so-called Kappa distribution. The presence of such distributions in different space plasmas suggests a universal mechanism for the creation of such suprathermal tails. Different theories have been proposed and are recalled in this review paper. The suprathermal particles have important consequences concerning the acceleration and the temperature that are well evidenced by the kinetic approach where no closure requires the distributions to be nearly Maxwellians. Moreover, the presence of the suprathermal particles take an important role in the wave-particle interactions.

  10. Dangerous and/or potential spaces

    DEFF Research Database (Denmark)

    Rasmussen, Lisa Rosén

    The alterations of entrance halls, walking areas, stairways and schoolyards pull together important aspects of the formation of the Danish primary and lower secondary school in the late 20th century. On the one hand these in-between spaces can be seen as shaped by considerations of the child’s well...... of Werner and Zimmermann’s histoire croisée (2006) – as important intersection points of entangled histories that fuel the changing understandings of what school, school life and school pupils are all about. This paper will explore how these in-between spaces at Danish schools have taken shape in complex...... material-discursive intra-actions between architects’ design of new school buildings, everyday furnishing and shifting concerns about the vulnerable and yet potential child. The paper will also look into the intra-actions between the physical layout of the schools and the increased focus on how to enhance...

  11. Recent advances in numerical simulation of space-plasma-physics problems

    Science.gov (United States)

    Birmingham, T. J.

    1983-01-01

    Computer simulations have become an increasingly popular, important and insightful tool for studying space plasmas. This review describes MHD and particle simulations, both of which treat the plasma and the electromagnetic field in which it moves in a self consistent fashion but on drastically different spatial and temporal scales. The complementary roles of simulation, observations and theory are stressed. Several examples of simulations being carried out in the area of magnetospheric plasma physics are described to illustrate the power, potential and limitations of the approach.

  12. Spacecraft charging and plasma interaction implications for large space systems

    Science.gov (United States)

    Miller, E.; Stauber, M.; Rossi, M.; Fischbein, W.

    1978-01-01

    Specific discharge mechanisms, plasma interactions, and scale effects associated with very large spacecraft are studied. The large area, low density character, and extensive use of non-conducting materials is thought to have a major impact on the performance and survivability of many large space systems.

  13. Potential applications of an electron cyclotron resonance multicusp plasma source

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, C.C.; Berry, L.A.; Gorbatkin, S.M.; Haselton, H.H.; Roberto, J.B.; Stirling, W.L. (Oak Ridge National Laboratory, Oak Ridge, TN (USA))

    1990-05-01

    An electron cyclotron resonance (ECR) multicusp plasmatron has been developed by feeding a multicusp bucket arc chamber with a compact ECR plasma source. This novel source produces large (about 25 cm diam), uniform (to within {plus minus}10%), dense ({gt}10{sup 11} cm{sup {minus}3}) plasmas of argon, helium, hydrogen, and oxygen. It has been operated to produce an oxygen plasma for etching 12.7 cm (5 in.) positive photoresist-coated silicon wafers with uniformity within {plus minus}8%. Results and potential applications of this new ECR plasma source for plasma processing of thin films are discussed.

  14. Coherent phase space matching for staging plasma and traditional accelerator using longitudinally tailored plasma structure

    CERN Document Server

    Xu, X L; Zhang, C J; Li, F; Wan, Y; Hua, J F; Pai, C -H; Lu, W; Yu, P; An, W; Mori, W B; Joshi, C; Hogan, M J

    2014-01-01

    For the further development of plasma based accelerators, phase space matching between plasma acceleration stages and between plasma stages and traditional accelerator components becomes a very critical issue for high quality high energy acceleration and its applications in light sources and colliders. Without proper matching, catastrophic emittance growth in the presence of finite energy spread may occur when the beam propagating through different stages and components due to the drastic differences of transverse focusing strength. In this paper we propose to use longitudinally tailored plasma structures as phase space matching components to properly guide the beam through stages. Theoretical analysis and full 3-dimensional particle-in-cell simulations are utilized to show clearly how these structures may work in four different scenarios. Very good agreements between theory and simulations are obtained.

  15. Thin current sheets caused by plasma flow gradients in space plasma

    Science.gov (United States)

    Nickeler, D.; Wiegelmann, T.

    2011-12-01

    To understand complex space plasma systems like the solar wind-magnetosphere coupling, we need to have a good knowledge of the slowly evolving equilibrium state. The slow change of external constraints on the system (for example boundary conditions or other external parameters) lead in many cases to the formation of current sheets. These current sheets can trigger micro-instabilities, which cause resistivity on fluid scales. Consequently resistive instabilities like magnetic reconnection can occur and the systems evolves dynamically. Therefore such a picture of quasi-magneto-hydro-static changes can explain the quasy-static phase of many space plasma before an eruption occurs. Within this work we extend the theory by the inclusion of a nonlinear stationary plasma flows. Our analysis shows that stationary plasma flows with strong flow gradients (for example the solar wind magnetosphere coupling) can be responsible for the existence or generation of current sheets.

  16. A model for ion-acoustic solitary waves with streaming non-Maxwellian electrons in space plasmas

    Science.gov (United States)

    Khalid Hussain, Shah; Nouman Sarwar, Qureshi Muhammad

    2016-04-01

    Solitons are nonlinear solitary structures and are integral part of space plasmas. Such nonlinear structures, accompanied by streaming electrons are frequently observed by various satellites in different regions of near Earth plasmas such as Earth's bow shock, magnetopause, auroral zone, etc. In this paper, we present a fluid model consisting streaming non-Maxwellian electrons along the magnetic field and derived the Sagdeev potential for fully nonlinear fluid equations. We found that compressive solitons can be developed in such a plasma. The results from our model can be used to interpret solitary structures in space plasmas when there is streaming electron obeying the non-Maxwellian distributions

  17. Summary of 2006 to 2010 FPMU Measurements of International Space Station Frame Potential Variations

    Science.gov (United States)

    Minow, Joseph I.; Wright, Kenneth H., Jr.; Chandler, Michael O.; Coffey, Victoria N.; Craven, Paul D.; Schneider, Todd A.; Parker, Linda N.; Ferguson, Dale C.; Koontz, Steve L.; Alred, John W.

    2010-01-01

    Electric potential variations on the International Space Station (ISS) structure in low Earth orbit are dominated by contributions from interactions of the United States (US) 160 volt solar arrays with the relatively high density, low temperature plasma environment and inductive potentials generated by motion of the large vehicle across the Earth?s magnetic field. The Floating Potential Measurement Unit (FPMU) instrument suite comprising two Langmuir probes, a plasma impedance probe, and a floating potential probe was deployed in August 2006 for use in characterizing variations in ISS potential, the state of the ionosphere along the ISS orbit and its effect on ISS charging, evaluating effects of payloads and visiting vehicles, and for supporting ISS plasma hazard assessments. This presentation summarizes observations of ISS frame potential variations obtained from the FPMU from deployment in 2006 through the current time. We first describe ISS potential variations due to current collection by solar arrays in the day time sector of the orbit including eclipse exit and entry charging events, potential variations due to plasma environment variations in the equatorial anomaly, and visiting vehicles docked to the ISS structure. Next, we discuss potential variations due to inductive electric fields generated by motion of the vehicle across the geomagnetic field and the effects of external electric fields in the ionosphere. Examples of night time potential variations at high latitudes and their possible relationship to auroral charging are described and, finally, we demonstrate effects on the ISS potential due to European Space Agency and US plasma contactor devices.

  18. Space Plasma Science as a Motivator for Education & Outreach

    Science.gov (United States)

    Dusenbery, Paul

    1999-11-01

    Education and public outreach (EPO) continue to play an important role in how science is funded by the federal government. The plasma science community has a responsibility to share their exciting science with the American public. Bruce Alberts, president of the National Academy of Sciences, and Neal Lane, former head of NSF, are on record as strong advocates of scientists becoming more actively and effectively engaged in K-12 science education reform. In addition, research directorates of funding agencies like NASA and NSF are increasingly encouraging (and in some cases requiring) the integration of science and education and greater scientist involvement in EPO. How does plasma science and scientists fit into this broader political and social landscape? How well does the public understand our science and technology? Are there ways to effectively engage the public that provide good visibility for plasma science? These questions and more will be addressed in this talk. The Space Science Institute (SSI), a nonprofit organization in Colorado, provides national leadership in developing innovative ways to translate the activities and resources of space and earth science research into exciting and effective K-12 and museum education programs. SSI’s mission is to link its space science research enterprise with its education programs. SSI has active programs in curriculum and exhibit development and professional development for both scientists about education and for educators about science. I will share with you one exhibit project and one curriculum project whose goals are to raise public understanding of space plasmas and by extension all of plasma science.

  19. Unique variable polarity plasma arc welding for space shuttle

    Science.gov (United States)

    Schwinghamer, R. J.

    1985-01-01

    Since the introduction of the Plasma Arc Torch in 1955 and subsequent to the work at Boeing in the 1960's, significant improvements crucial to success have been made in the Variable Polarity Plasma Arc (VPPA) Process at the Marshall Space Flight Center. Several very important advantages to this process are given, and the genesis of PA welding, the genesis of VPPA welding, special equiment requirements, weld property development, results with other aluminum alloys, and the eventual successful VPPA transition to production operations are discussed.

  20. Concept Study of Radio Frequency (RF Plasma Thruster for Space Propulsion

    Directory of Open Access Journals (Sweden)

    Anna-Maria Theodora ANDREESCU

    2016-12-01

    Full Text Available Electric thrusters are capable of accelerating ions to speeds that are impossible to reach using chemical reaction. Recent advances in plasma-based concepts have led to the identification of electromagnetic (RF generation and acceleration systems as able to provide not only continuous thrust, but also highly controllable and wide-range exhaust velocities. For Future Space Propulsion there is a pressing need for low pressure, high mass flow rate and controlled ion energies. This paper explores the potential of using RF heated plasmas for space propulsion in order to mitigate the electric propulsion problems caused by erosion and gain flexibility in plasma manipulation. The main key components of RF thruster architecture are: a feeding system able to provide the required neutral gas flow, plasma source chamber, antenna/electrodes wrapped around the discharge tube and optimized electromagnetic field coils for plasma confinement. A preliminary analysis of system performance (thrust, specific impulse, efficiency is performed along with future plans of Space Propulsion based on this new concept of plasma mechanism.

  1. From laboratory plasma experiments to space plasma experiments with `CubeSat' nano-satellites

    Science.gov (United States)

    Charles, Christine

    2016-09-01

    `CubeSat' nano-satellites provide low-cost access to space. SP3 laboratory's involvement in the European Union `QB50' `CubeSat' project [www.qb50.eu] which will launch into space 50 `CubeSats' from 27 Countries to study the ionosphere and the lower thermosphere will be presented. The Chi Kung laboratory plasma experiment and the Helicon Double Layer Thruster prototype can be tailored to investigate expanding magnetized plasma physics relevant to space physics (solar corona, Earth's aurora, adiabatic expansion and polytropic studies). Chi Kung is also used as a plasma wind tunnel for ground-based calibration of the University College London QB50 Ion Neutral Mass Spectrometer. Space qualification of the three Australian QB50 `CubeSats' (June 2016) is carried out in the WOMBAT XL space simulation chamber. The QB50 satellites have attitude control but altitude control is not a requirement. SP3 is developing end-to-end miniaturised radiofrequency plasma propulsion systems (such as the Pocket Rocket and the MiniHel thrusters with power and propellant sub-systems) for future `CubeSat' missions.

  2. The shear viscosity of gauge theory plasma with chemical potentials

    CERN Document Server

    Benincasa, P; Naryshkin, R; Benincasa, Paolo; Buchel, Alex; Naryshkin, Roman

    2007-01-01

    We consider strongly coupled gauge theory plasma with conserved global charges that allow for a dual gravitational description. We study the shear viscosity of the gauge theory plasma in the presence of chemical potentials for these charges. Using gauge theory/string theory correspondence we prove that at large 't Hooft coupling the ratio of the shear viscosity to the entropy density is universal.

  3. The shear viscosity of gauge theory plasma with chemical potentials

    Science.gov (United States)

    Benincasa, Paolo; Buchel, Alex; Naryshkin, Roman

    2007-02-01

    We consider strongly coupled gauge theory plasma with conserved global charges that allow for a dual gravitational description. We study the shear viscosity of the gauge theory plasma in the presence of chemical potentials for these charges. Using gauge theory/string theory correspondence we prove that at large 't Hooft coupling the ratio of the shear viscosity to the entropy density is universal.

  4. Thin current sheets caused by plasma flow gradients in space and astrophysical plasma

    Directory of Open Access Journals (Sweden)

    D. H. Nickeler

    2010-08-01

    Full Text Available Strong gradients in plasma flows play a major role in space and astrophysical plasmas. A typical situation is that a static plasma equilibrium is surrounded by a plasma flow, which can lead to strong plasma flow gradients at the separatrices between field lines with different magnetic topologies, e.g., planetary magnetospheres, helmet streamers in the solar corona, or at the boundary between the heliosphere and interstellar medium. Within this work we make a first step to understand the influence of these flows towards the occurrence of current sheets in a stationary state situation. We concentrate here on incompressible plasma flows and 2-D equilibria, which allow us to find analytic solutions of the stationary magnetohydrodynamics equations (SMHD. First we solve the magnetohydrostatic (MHS equations with the help of a Grad-Shafranov equation and then we transform these static equilibria into a stationary state with plasma flow. We are in particular interested to study SMHD-equilibria with strong plasma flow gradients perpendicular to separatrices. We find that induced thin current sheets occur naturally in such situations. The strength of the induced currents depend on the Alfvén Mach number and its gradient, and on the magnetic field.

  5. Fast Magnetic Reconnection: Bridging Laboratory and Space Plasma Physics

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharjee, Amitava [University New Hampshire- Durham

    2012-02-16

    Recent developments in experimental and theoretical studies of magnetic reconnection hold promise for providing solutions to outstanding problems in laboratory and space plasma physics. Examples include sawtooth crashes in tokamaks, substorms in the Earth’s Magnetosphere, eruptive solar flares, and more recently, fast reconnection in laser-produced high energy density plasmas. In each of these examples, a common and long-standing challenge has been to explain why fast reconnection proceeds rapidly from a relatively quiescent state. In this talk, we demonstrate the advantages of viewing these problems and their solutions from a common perspective. We focus on some recent, surprising discoveries regarding the role of secondary plasmoid instabilities of thin current sheets. Nonlinearly, these instabilities lead to fast reconnection rates that are very weakly dependent on the Lundquist number of the plasma.

  6. Vasyliunas-Cairns distribution function for space plasma species

    Science.gov (United States)

    Abid, A. A.; Ali, S.; Du, J.; Mamun, A. A.

    2015-08-01

    A more generalized form of non-Maxwellian distribution function (that can be named as Vasyliunas-Cairns distribution function) is introduced. Its basic properties are numerically analyzed by the variation of two important parameters, namely, α (which shows the amount of energetic particles present in the plasma system) and κ (which shows the superthermality of the plasma species). It has been observed that (i) for α → 0 ( κ → ∞ ), the Vasyliunas-Cairns distribution function reduces to the Vasyliunas or κ (Cairns or nonthermal) distribution function; (ii) for α → 0 and κ → ∞ , it reduces to the Maxwellian distribution function; and (iii) the effect of the parameter α (κ) significantly modifies the basic properties of the Vasyliunas (Cairns) distribution function. The applications of this generalized non-Maxwellian distribution function (Vasyliunas-Cairns distribution function) in different space plasma situations are briefly discussed.

  7. Plasma density fluctuations observed during Space Shuttle Orbiter water releases

    Science.gov (United States)

    Pickett, J. S.; D'Angelo, N.; Kurth, W. S.

    1989-01-01

    Observations by the Langmuir probe on the Plasma Diagnostics Package flown as part of the Spacelab 2 mission in the summer of 1985 show a strong increase in the level of turbulence near the Shuttle Orbiter during operations in which liquid water is released. The spectrum of the plasma density fluctuations peaks at the lowest frequencies measured (a few Hz) and extends up to a few kHz, near the lower hybrid frequency. Two potential mechanisms for generating the plasma turbulence are suggested which are both based on the production of water ions as a result of charge exchange with the ambient oxygen ions in the ionosphere. The first mechanism proposed is the ion-plasma instability which arises from the drift of the contaminant with respect to the ambient oxygen ions. The other mechanism proposed is the Ott-Farley instability, which is a result of the ring distribution formed by the 'pick-up' water ions.

  8. NASA Space Weather Center Services: Potential for Space Weather Research

    Science.gov (United States)

    Zheng, Yihua; Kuznetsova, Masha; Pulkkinen, Antti; Taktakishvili, A.; Mays, M. L.; Chulaki, A.; Lee, H.; Hesse, M.

    2012-01-01

    The NASA Space Weather Center's primary objective is to provide the latest space weather information and forecasting for NASA's robotic missions and its partners and to bring space weather knowledge to the public. At the same time, the tools and services it possesses can be invaluable for research purposes. Here we show how our archive and real-time modeling of space weather events can aid research in a variety of ways, with different classification criteria. We will list and discuss major CME events, major geomagnetic storms, and major SEP events that occurred during the years 2010 - 2012. Highlights of major tools/resources will be provided.

  9. Studies of Particle Wake Potentials in Plasmas

    Science.gov (United States)

    Ellis, Ian; Graziani, Frank; Glosli, James; Strozzi, David; Surh, Michael; Richards, David; Decyk, Viktor; Mori, Warren

    2011-10-01

    Fast Ignition studies require a detailed understanding of electron scattering, stopping, and energy deposition in plasmas with variable values for the number of particles within a Debye sphere. Presently there is disagreement in the literature concerning the proper description of these processes. Developing and validating proper descriptions requires studying the processes using first-principle electrostatic simulations and possibly including magnetic fields. We are using the particle-particle particle-mesh (PPPM) code ddcMD and the particle-in-cell (PIC) code BEPS to perform these simulations. As a starting point in our study, we examine the wake of a particle passing through a plasma in 3D electrostatic simulations performed with ddcMD and with BEPS using various cell sizes. In this poster, we compare the wakes we observe in these simulations with each other and predictions from Vlasov theory. Prepared by LLNL under Contract DE-AC52-07NA27344 and by UCLA under Grant DE-FG52-09NA29552.

  10. Educational software for the visualization of space plasma processes

    Science.gov (United States)

    Russell, C. T.; Le, G.; Luhmann, J. G.; Littlefield, B.

    1995-01-01

    The UCLA Space Physics Group has developed educational software composed of a series of modules to assist students with understanding basic concepts of space plasmas and charged particle motion. Present modules cover planetary magnetospheres, charged particle motion, cold plasma waves, collisionless shock waves, and solar wind. The software is designed around the principle that students can learn more by doing rather than by reading or listening. The programs provide a laboratory-like environment in which the student can control, observe, and measure complex behavior. The interactive graphics environment allows the student to visualize the results of his or her experimentation and to try different parameters as desired. The current version of the software runs on UNIX-based operating systems in an X-Windows environment. It has been used in a classroom setting at both UCLA and the University of California at San Diego.

  11. The role of magnetohydrodynamics in heliospheric space plasma physics research

    Science.gov (United States)

    Dryer, Murray; Smith, Zdenka Kopal; Wu, Shi Tsan

    1988-01-01

    Magnetohydrodynamics (MHD) is a fairly recent extension of the field of fluid mechanics. While much remains to be done, it has successfully been applied to the contemporary field of heliospheric space plasma research to evaluate the 'macroscopic picture' of some vital topics via the use of conducting fluid equations and numerical modeling and simulations. Some representative examples from solar and interplanetary physics are described to demonstrate that the continuum approach to global problems (while keeping in mind the assumptions and limitations therein) can be very successful in providing insight and large scale interpretations of otherwise intractable problems in space physics.

  12. Potential applications of an electron cyclotron resonance multicusp plasma source

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, C.C.; Berry, L.A.; Gorbatkin, S.M.; Haselton, H.H.; Roberto, J.B.; Schechter, D.E.; Stirling, W.L.

    1990-03-01

    An electric cyclotron resonance (ECR) multicusp plasmatron has been developed by feeding a multicusp bucket arc chamber with a compact ECR plasma source. This novel source produces large (about 25-cm- diam), uniform (to within {plus minus}10%), dense (>10{sup 11}--cm{sup {minus}3}) plasmas of argon, helium, hydrogen, and oxygen. It has been operated to produce an oxygen plasma for etching 12.7-cm (5-in.) positive photoresist-coated silicon wafers with uniformity within {plus minus}8%. Following a brief review of the large plasma source developed at Oak Ridge National Laboratory, the configuration and operation of the source are described and a discharge model is presented. Results from this new ECR plasma source and potential applications for plasma processing of thin films are discussed. 21 refs., 10 figs.

  13. Role of grain size and particle velocity distribution in secondary electron emission in space plasmas

    Science.gov (United States)

    Chow, V. W.; Mendis, D. A.; Rosenberg, M.

    1993-01-01

    By virtue of being generally immersed in a plasma environment, cosmic dust is necessarily electrically charged. The fact that secondary emission plays an important role in determining the equilibrium grain potential has long been recognized, but the fact that the grain size plays a crucial role in this equilibrium potential, when secondary emission is important, has not been widely appreciated. Using both conducting and insulating spherical grains of various sizes and also both Maxwellian and generalized Lorentzian plasmas (which are believed to represent certain space plasmas), we have made a detailed study of this problem. In general, we find that the secondary emission yield delta increases with decreasing size and becomes very large for grains whose dimensions are comparable to the primary electron penetration depth, such as in the case of the very small grains observed at comet Halley and inferred in the interstellar medium. Moreover, we observed that delta is larger for insulators and equilibrium potentials are generally more positive when the plasma has a broad non-Maxwellian tail. Interestingly, we find that for thermal energies that are expected in several cosmic regions, grains of different sizes can have opposite charge, the smaller ones being positive while the larger ones are negative. This may have important consequences for grain accretion in polydisperse dusty space plasmas.

  14. Awakening the potential of plasma acceleration

    CERN Multimedia

    Katarina Anthony

    2014-01-01

    Civil engineering has begun for the new AWAKE experiment, which looks to push the boundaries of particle acceleration. This proof-of-principle experiment will harness the power of wakefields generated by proton beams in plasma cells, producing accelerator gradients hundreds of times higher than those used in current RF cavities.   Civil engineering works are currently ongoing at the AWAKE facility. As one of CERN's accelerator R&D experiments, the AWAKE project is rather unique. Like all of CERN's experiments, AWAKE is a collaborative endeavour with institutes and organisations participating around the world. "But unlike fixed-target experiments, where the users take over once CERN has delivered the facility, in AWAKE, the synchronised proton, electron and laser beams provided by CERN are an integral part of the experiment," explains Edda Gschwendtner, CERN AWAKE project leader. "So, of course, CERN's involvement in the project goes well...

  15. Effect of Substrate Potential on Plasma Parameters of Magnetic Multicusp Plasma Source

    Science.gov (United States)

    Ueda, Yoshio; Goto, Masahiro

    1998-06-01

    The effect of substrate potential on plasmas produced in a magnetic multicusp plasma source has been studied experimentally. Plasma parameters such as electron temperature and plasma potential are estimated from electron energy distribution function numerically calculated from probe current-voltage characteristics. For a substrate potential of -150 V with respect to the source chamber, which is much lower than substrate floating potentials, the plasma parameters are not affected by the application of the potential. However, for the case where the substrate is shorted with the source chamber, the high energy component of electrons significantly decreases in comparison with the floating case leading to the reduction of electron temperature. In this case, plasma potential is positive with respect to the substrate to suppress electron loss but its absolute value is only of the order of electron temperature in eV, which is much lower than the potential between the plasma and the substrate in the floating case. This discharge mode could be advantageous in significantly reducing the ion impact energy to the substrate plate.

  16. Formation and interaction of multiple coherent phase space structures in plasma

    Science.gov (United States)

    Kakad, Amar; Kakad, Bharati; Omura, Yoshiharu

    2017-06-01

    The head-on collision of multiple counter-propagating coherent phase space structures associated with the ion acoustic solitary waves (IASWs) in plasmas composed of hot electrons and cold ions is studied here by using one-dimensional Particle-in-Cell simulation. The chains of counter-propagating IASWs are generated in the plasma by injecting the Gaussian perturbations in the equilibrium electron and ion densities. The head-on collisions of the counter-propagating electron and ion phase space structures associated with IASWs are allowed by considering the periodic boundary condition in the simulation. Our simulation shows that the phase space structures are less significantly affected by their collision with each other. They emerge out from each other by retaining their characteristics, so that they follow soliton type behavior. We also find that the electrons trapped within these IASW potentials are accelerated, while the ions are decelerated during the course of their collisions.

  17. Phase Space Dynamics of Ionization Injection in Plasma Based Accelerators

    CERN Document Server

    Xu, X L; Li, F; Zhang, C J; Yan, L X; Du, Y C; Huang, W H; Chen, H B; Tang, C X; Lu, W; Yu, P; An, W; Mori, W B; Joshi, C

    2013-01-01

    The evolution of beam phase space in ionization-induced injection into plasma wakefields is studied using theory and particle-in-cell (PIC) simulations. The injection process causes special longitudinal and transverse phase mixing leading initially to a rapid emittance growth followed by oscillation, decay, and eventual slow growth to saturation. An analytic theory for this evolution is presented that includes the effects of injection distance (time), acceleration distance, wakefield structure, and nonlinear space charge forces. Formulas for the emittance in the low and high space charge regimes are presented. The theory is verified through PIC simulations and a good agreement is obtained. This work shows how ultra-low emittance beams can be produced using ionization-induced injection.

  18. The Space Station Photovoltaic Panels Plasma Interaction Test Program: Test plan and results

    Science.gov (United States)

    Nahra, Henry K.; Felder, Marian C.; Sater, Bernard L.; Staskus, John V.

    1989-01-01

    The Plasma Interaction Test performed on two space station solar array panels is addressed. This includes a discussion of the test requirements, test plan, experimental set-up, and test results. It was found that parasitic current collection was insignificant (0.3 percent of the solar array delivered power). The measured arcing threshold ranged from -210 to -457 V with respect to the plasma potential. Furthermore, the dynamic response of the panels showed the panel time constant to range between 1 and 5 microsec, and the panel capacitance to be between .01 and .02 microF.

  19. The Space Station photovoltaic panels plasma interaction test program - Test plan and results

    Science.gov (United States)

    Nahra, Henry K.; Felder, Marian C.; Sater, Bernard L.; Staskus, John V.

    1990-01-01

    The plasma Interaction Test performed on two space station solar array panels is addressed. This includes a discussion of the test requirements, test plan, experimental set-up, and test results. It was found that parasitic current collection was insignificant (0.3 percent of the solar array delivered power). The measured arcing threshold ranged from -210 to -457 V with respect to the plasma potential. Furthermore, the dynamic response of the panels showed the panel time constant to range between 1 and 5 microsec, and the panel capacitance to be between .01 and .02 microF.

  20. Nonlinear kinetic Alfvén waves with non-Maxwellian electron population in space plasmas

    Science.gov (United States)

    Masood, W.; Qureshi, M. N. S.; Yoon, P. H.; Shah, H. A.

    2015-01-01

    The present work discusses the effects of non-Maxwellian electron distributions on kinetic Alfvén waves in low-beta plasmas. Making use of the two-potential theory and employing the Sagdeev potential approach, the existence of solitary kinetic Alfvén waves having arbitrary amplitude is investigated. It is found that the use of non-Maxwellian population of electrons in the study of kinetic Alfvén waves leads to solutions corresponding to solitary structures that do not exist for Maxwellian electrons. The present investigation solves the riddle of plasma density fluctuations associated with strong electromagnetic perturbations observed by the Freja satellite. The present findings can also be applied to regions of space where various satellite missions have observed the presence of suprathermal populations of plasma species and where the low β assumption is valid.

  1. Spaced resolved analysis of suprathermal electrons in dense plasma

    Directory of Open Access Journals (Sweden)

    Moinard A.

    2013-11-01

    Full Text Available The investigation of the hot electron fraction is a crucial topic for high energy density laser driven plasmas: first, energy losses and radiative properties depend strongly on the hot electron fraction and, second, in ICF hohlraums suprathermal electrons preheat the D-T-capsule and seriously reduce the fusion performance. In the present work we present our first experimental and theoretical studies to analyze single shot space resolved hot electron fractions inside dense plasmas via optically thin X-ray line transitions from autoionizing states. The benchmark experiment has been carried out at an X-pinch in order to create a dense, localized plasma with a well defined symmetry axis of hot electron propagation. Simultaneous high spatial and spectral resolution in the X-ray spectral range has been obtained with a spherically bent quartz Bragg crystal. The high performance of the X-ray diagnostics allowed to identify space resolved hot electron fractions via the X-ray spectral distribution of multiple excited states.

  2. Study of the plasma interference with high voltage electrode array for space power application

    OpenAIRE

    Iwasa, Minoru; TANAKA, KOJI; Sasaki, Susumu; ODAWARA, OSAMU; 岩佐 稔; 田中 孝治; 佐々木 進; 小田原 修

    2005-01-01

    We are studying the problems associated with high voltage power systems in space. Especially we are interested in the potential distribution of the solar array that is resistant to the electrical discharge. We have carried out experiments on the interaction between the high voltage solar array and the ambient plasma. In the experiment, an array of electrodes distributed on the insulation panel was used to simulate the inter-connectors of the solar array. An electrode array without the insulat...

  3. Interaction potential of microparticles in a plasma: role of collisions with plasma particles.

    Science.gov (United States)

    Khrapak, S A; Ivlev, A V; Morfill, G

    2001-10-01

    The interaction potential of two charged microparticles in a plasma is studied. Violation of the plasma equilibrium around the dust particles due to plasma-particle inelastic collisions results in three effects: long-range (non-Yukawa) electrostatic repulsion, attraction due to ion shadowing, and attraction or repulsion due to neutral shadowing (depending on the sign of the temperature difference between the particle surface and neutral gas). An analytical expression for the total potential is obtained and compared with previous theoretical results. The relative contribution of these effects is studied in two limiting cases-an isotropic bulk plasma and the plasma sheath region. The results obtained are compared with existing experimental results on pair particle interaction. The possibility of the so-called dust molecule formation is discussed.

  4. The shear viscosity of gauge theory plasma with chemical potentials

    Energy Technology Data Exchange (ETDEWEB)

    Benincasa, Paolo [Department of Applied Mathematics, University of Western Ontario, London, Ontario N6A 5B7 (Canada); Buchel, Alex [Department of Applied Mathematics, University of Western Ontario, London, Ontario N6A 5B7 (Canada) and Perimeter Institute for Theoretical Physics, Waterloo, Ontario N2J 2W9 (Canada)]. E-mail: abuchel@perimeterinstitute.ca; Naryshkin, Roman [Department of Applied Mathematics, University of Western Ontario, London, Ontario N6A 5B7 (Canada); Physics Department, Taras Shevchenko Kiev National University, Prosp. Glushkova 6, Kiev 03022 (Ukraine)

    2007-02-08

    We consider strongly coupled gauge theory plasma with conserved global charges that allow for a dual gravitational description. We study the shear viscosity of the gauge theory plasma in the presence of chemical potentials for these charges. Using gauge theory/string theory correspondence we prove that at large 't Hooft coupling the ratio of the shear viscosity to the entropy density is universal.

  5. PKE-Nefedov: plasma crystal experiments on the International Space Station

    Energy Technology Data Exchange (ETDEWEB)

    Nefedov, Anatoli P [Institute for High Energy Densities, Russian Academy of Sciences, 127412 Moscow (Russian Federation); Morfill, Gregor E [Centre for Interdisciplinary Plasma Science, Max-Planck-Institut fuer Extraterrestrische Physik, D-85740 Garching (Germany); Fortov, Vladimir E [Institute for High Energy Densities, Russian Academy of Sciences, 127412 Moscow (Russian Federation); Thomas, Hubertus M [Centre for Interdisciplinary Plasma Science, Max-Planck-Institut fuer Extraterrestrische Physik, D-85740 Garching (Germany); Rothermel, Hermann [Centre for Interdisciplinary Plasma Science, Max-Planck-Institut fuer Extraterrestrische Physik, D-85740 Garching (Germany); Hagl, Tanja [Centre for Interdisciplinary Plasma Science, Max-Planck-Institut fuer Extraterrestrische Physik, D-85740 Garching (Germany); Ivlev, Alexei V [Centre for Interdisciplinary Plasma Science, Max-Planck-Institut fuer Extraterrestrische Physik, D-85740 Garching (Germany); Zuzic, Milenko [Centre for Interdisciplinary Plasma Science, Max-Planck-Institut fuer Extraterrestrische Physik, D-85740 Garching (Germany); Klumov, Boris A [Centre for Interdisciplinary Plasma Science, Max-Planck-Institut fuer Extraterrestrische Physik, D-85740 Garching (Germany); Lipaev, Andrey M [Institute for High Energy Densities, Russian Academy of Sciences, 127412 Moscow (Russian Federation); Molotkov, Vladimir I [Institute for High Energy Densities, Russian Academy of Sciences, 127412 Moscow (Russian Federation); Petrov, Oleg F [Institute for High Energy Densities, Russian Academy of Sciences, 127412 Moscow (Russian Federation); Gidzenko, Yuri P [Y Gagarin Cosmonauts Training Centre, 141160 Star City, Moscow Region (Russian Federation); Krikalev, Sergey K [SP Korolev RSC Energia, Korolev 141070, Moscow Region (Russian Federation); Shepherd, William [Expedition 1 Crew, International Space Station (ISS) (Country Unknown)] [and others

    2003-04-01

    The plasma crystal experiment PKE-Nefedov, the first basic science experiment on the International Space Station (ISS), was installed in February 2001 by the first permanent crew. It is designed for long-term investigations of complex plasmas under microgravity conditions. 'Complex plasmas' contain ions, electrons, neutrals and small solid particles - normally in the micrometre range. These microparticles obtain thousands of elementary charges and interact with each other via a 'screened' Coulomb potential. Complex plasmas are of special interest, because they can form liquid and crystalline states (Thomas et al 1994 Phys. Rev. Lett. 73 652-5, Chu and I 1994 Phys. Rev. Lett. 72 4009-12) and are observable at the kinetic level. In experiments on Earth the microparticles are usually suspended against gravity in strong electric fields. This creates asymmetries, stresses and pseudo-equilibrium states with sufficient free energy to readily become unstable. Under microgravity conditions the microparticles move into the bulk of the plasma (Morfill et al 1999 Phys. Rev. Lett. 83 1598), experiencing much weaker volume forces than on Earth. This allows investigations of the thermodynamics of strongly coupled plasma states under substantially stress-free conditions. In this first paper we report our results on plasma crystals, in particular the first experimental observations of bcc lattice structures.

  6. Physics of Collisionless Shocks Space Plasma Shock Waves

    CERN Document Server

    Balogh, André

    2013-01-01

    The present book provides a contemporary systematic treatment of shock waves in high-temperature collisionless plasmas as are encountered in near Earth space and in Astrophysics. It consists of two parts. Part I develops the complete theory of shocks in dilute hot plasmas under the assumption of absence of collisions among the charged particles when the interaction is mediated solely by the self-consistent electromagnetic fields. Such shocks are naturally magnetised implying that the magnetic field plays an important role in their evolution and dynamics. This part treats both subcritical shocks, which dissipate flow energy by generating anomalous resistance or viscosity, and supercritical shocks. The main emphasis is, however, on super-critical shocks where the anomalous dissipation is insufficient to retard the upstream flow. These shocks, depending on the direction of the upstream magnetic field, are distinguished as quasi-perpendicular and quasi-parallel shocks which exhibit different behaviours, reflecti...

  7. Collisionless shocks in space plasmas structure and accelerated particles

    CERN Document Server

    Burgess, David

    2015-01-01

    Shock waves are an important feature of solar system plasmas, from the solar corona out to the edge of the heliosphere. This engaging introduction to collisionless shocks in space plasmas presents a comprehensive review of the physics governing different types of shocks and processes of particle acceleration, from fundamental principles to current research. Motivated by observations of planetary bow shocks, interplanetary shocks and the solar wind termination shock, it emphasises the physical theory underlying these shock waves. Readers will develop an understanding of the complex interplay between particle dynamics and the electric and magnetic fields that explains the observations of in situ spacecraft. Written by renowned experts in the field, this up-to-date text is the ideal companion for both graduate students new to heliospheric physics and researchers in astrophysics who wish to apply the lessons of solar system shocks to different astrophysical environments.

  8. Transient plasma potential in pulsed dual frequency inductively coupled plasmas and effect of substrate biasing

    Science.gov (United States)

    Mishra, Anurag; Yeom, Geun Young

    2016-09-01

    An electron emitting probe in saturated floating potential mode has been used to investigate the temporal evolution of plasma potential and the effect of substrate RF biasing on it for pulsed dual frequency (2 MHz/13.56 MHz) inductively coupled plasma (ICP) source. The low frequency power (P2MHz) has been pulsed at 1 KHz and a duty ratio of 50%, while high frequency power (P13.56MHz) has been used in continuous mode. The substrate has been biased with a separate bias power at (P12.56MHz) Argon has been used as a discharge gas. During the ICP power pulsing, three distinct regions in a typical plasma potential profile, have been identified as `initial overshoot', pulse `on-phase' and pulse `off-phase'. It has been found out that the RF biasing of the substrate significantly modulates the temporal evolution of the plasma potential. During the initial overshoot, plasma potential decreases with increasing RF biasing of the substrate, however it increases with increasing substrate biasing for pulse `on-phase' and `off-phase'. An interesting structure in plasma potential profile has also been observed when the substrate bias is applied and its evolution depends upon the magnitude of bias power. The reason of the evolution of this structure may be the ambipolar diffusion of electron and its dependence on bias power.

  9. Exploring Transitions of Space Plasmas Out of Equilibrium

    Science.gov (United States)

    Livadiotis, G.; McComas, D. J.

    2010-05-01

    Space plasmas from the solar wind to planetary magnetospheres and the outer heliosphere are systems in stationary states out of equilibrium. Empirical kappa distributions, which naturally emerge from Tsallis Statistics, successfully describe these space plasmas. The Tsallis formalism offers a solid statistical foundation and provides a set of proven tools for understanding these distributions, including a consistent definition of temperature—the physical temperature, which characterizes the non-equilibrium stationary states. Here, we develop a measure of the "thermodynamic distance" of stationary states away from equilibrium. The stationary states are labeled by the value of the entropic q-index, lying in a spectrum from q = 1 (equilibrium) to the maximum value of q, which specifies the furthest possible stationary state from equilibrium. We call this the "q-frozen state," because as a system approaches this state, it behaves analogously to when its temperature approaches absolute zero. We also introduce a novel isothermal procedure that describes a system's transition into different stationary states by varying the q-index, and show how the variation of temperature can be realized using an "iso-metastability" procedure, in which the system remains in a fixed stationary state. These innovations allow a generalization of the zeroth law of thermodynamics to cover stationary states out of equilibrium. By expressing the entropy in terms of the q-index, we show the detailed paths by which the transition of stationary states evolves toward equilibrium following the dynamics of a characteristic difference equation along the q-indices. This naturally exhibits certain stationary states out of equilibrium that are frequently observed in space plasmas.

  10. Model of strong stationary vortex turbulence in space plasmas

    Directory of Open Access Journals (Sweden)

    G. D. Aburjania

    2009-01-01

    Full Text Available This paper investigates the macroscopic consequences of nonlinear solitary vortex structures in magnetized space plasmas by developing theoretical model of plasma turbulence. Strongly localized vortex patterns contain trapped particles and, propagating in a medium, excite substantial density fluctuations and thus, intensify the energy, heat and mass transport processes, i.e., such vortices can form strong vortex turbulence. Turbulence is represented as an ensemble of strongly localized (and therefore weakly interacting vortices. Vortices with various amplitudes are randomly distributed in space (due to collisions. For their description, a statistical approach is applied. It is supposed that a stationary turbulent state is formed by balancing competing effects: spontaneous development of vortices due to nonlinear twisting of the perturbations' fronts, cascading of perturbations into short scales (direct spectral cascade and collisional or collisionless damping of the perturbations in the short-wave domain. In the inertial range, direct spectral cascade occurs through merging structures via collisions. It is shown that in the magneto-active plasmas, strong turbulence is generally anisotropic Turbulent modes mainly develop in the direction perpendicular to the local magnetic field. It is found that it is the compressibility of the local medium which primarily determines the character of the turbulent spectra: the strong vortex turbulence forms a power spectrum in wave number space. For example, a new spectrum of turbulent fluctuations in k−8/3 is derived which agrees with available experimental data. Within the framework of the developed model particle diffusion processes are also investigated. It is found that the interaction of structures with each other and particles causes anomalous diffusion in the medium. The effective coefficient of diffusion has a square root dependence on the stationary level of noise.

  11. Screened Coulomb potential in a flowing magnetized plasma

    CERN Document Server

    Joost, Jan-Philip; Kählert, Hanno; Arran, Christopher; Bonitz, Michael

    2014-01-01

    The electrostatic potential of a moving dust grain in a complex plasma with magnetized ions is computed using linear response theory, thereby extending our previous work for unmagnetized plasmas [P. Ludwig et al., New J. Phys. 14, 053016 (2012)]. In addition to the magnetic field, our approach accounts for a finite ion temperature as well as ion-neutral collisions. Our recently introduced code \\texttt{Kielstream} is used for an efficient calculation of the dust potential. Increasing the magnetization of the ions, we find that the shape of the potential crucially depends on the Mach number $M$. In the regime of subsonic ion flow ($M1$ the magnetic field effectively suppresses the plasma wakefield.

  12. Interrelationship between Plasma Experiments in the Laboratory and in Space

    Energy Technology Data Exchange (ETDEWEB)

    Koepke, Mark E. [West Virginia Univ., Morgantown, WV (United States)

    2017-05-25

    Funds were expended to offset the travel costs of three students and three postdoctoral research associates to participate in and present work at the 2015 International Workshop on the Interrelationship between Plasma Experiments in the Laboratory and in Space (IPELS2015), 23-28 August 2015, Pitlochry, Scotland, UK. Selection was priority-ranked by lab-space engagement, first, and topic relevance, second. Supplementary selection preference was applied to under-represented populations, applicants lacking available travel-resources in their home research group, applicants unusually distant from the conference venue, and the impact of the applicant’s attendance in increasing the diversity of conference participation. One support letter per student was required. The letters described the specific benefit of IPELS2015 to the student dissertation or the postdoc career development, and document the evidence for the ordering criteria.

  13. Interaction potentials and thermodynamic properties of two component semiclassical plasma

    Energy Technology Data Exchange (ETDEWEB)

    Ramazanov, T. S.; Moldabekov, Zh. A.; Ismagambetova, T. N. [Al-Farabi Kazakh National University, IETP, 71 al-Farabi Av., Almaty 050040 (Kazakhstan); Gabdullin, M. T. [Al-Farabi Kazakh National University, NNLOT, 71 al-Farabi Av., Almaty 050040 (Kazakhstan)

    2014-01-15

    In this paper, the effective interaction potential in two component semiclassical plasma, taking into account the long-range screening and the quantum-mechanical diffraction effects at short distances, is obtained on the basis of dielectric response function method. The structural properties of the semiclassical plasma are considered. The thermodynamic characteristics (the internal energy and the equation of state) are calculated using two methods: the method of effective potentials and the method of micropotentials with screening effect taken into account by the Ornstein-Zernike equation in the HNC approximation.

  14. Hollow cathode heater development for the Space Station plasma contactor

    Science.gov (United States)

    Soulas, George C.

    1993-01-01

    A hollow cathode-based plasma contactor has been selected for use on the Space Station. During the operation of the plasma contactor, the hollow cathode heater will endure approximately 12000 thermal cycles. Since a hollow cathode heater failure would result in a plasma contactor failure, a hollow cathode heater development program was established to produce a reliable heater design. The development program includes the heater design, process documents for both heater fabrication and assembly, and heater testing. The heater design was a modification of a sheathed ion thruster cathode heater. Three heaters have been tested to date using direct current power supplies. Performance testing was conducted to determine input current and power requirements for achieving activation and ignition temperatures, single unit operational repeatability, and unit-to-unit operational repeatability. Comparisons of performance testing data at the ignition input current level for the three heaters show the unit-to-unit repeatability of input power and tube temperature near the cathode tip to be within 3.5 W and 44 degrees C, respectively. Cyclic testing was then conducted to evaluate reliability under thermal cycling. The first heater, although damaged during assembly, completed 5985 ignition cycles before failing. Two additional heaters were subsequently fabricated and have completed 3178 cycles to date in an on-going test.

  15. Magnetic Reconnection: A Fundamental Process in Space Plasmas

    Science.gov (United States)

    Hesse, Michael

    2010-01-01

    For many years, collisionless magnetic reconnect ion has been recognized as a fundamental process, which facilitates plasma transport and energy release in systems ranging from the astrophysical plasmas to magnetospheres and even laboratory plasma. Beginning with work addressing solar dynamics, it has been understood that reconnection is essential to explain solar eruptions, the interaction of the solar wind with the magnetosphere, and the dynamics of the magnetosphere. Accordingly, the process of magnetic reconnection has been and remains a prime target for space-based and laboratory studies, as well as for theoretical research. Much progress has been made throughout the years, beginning with indirect verifications by studies of processes enabled by reconnection, such as Coronal Mass Ejections, Flux Transfer Events, and Plasmoids. Theoretical advances have accompanied these observations, moving knowledge beyond the Sweet-Parker theory to the recognition that other, collisionless, effects are available and likely to support much faster reconnect ion rates. At the present time we are therefore near a break-through in our understanding of how collisionless reconnect ion works. Theory and modeling have advanced to the point that two competing theories are considered leading candidates for explaining the microphysics of this process. Both theories predict very small spatial and temporal scales. which are. to date, inaccessible to space-based or laboratory measurements. The need to understand magnetic reconnect ion has led NASA to begin the implementation of a tailored mission, Magnetospheric MultiScale (MMS), a four spacecraft cluster equipped to resolve all relevant spatial and temporal scales. In this presentation, we present an overview of current knowledge as well as an outlook towards measurements provided by MMS.

  16. Energetic particles in laboratory, space and astrophysical plasmas

    Science.gov (United States)

    McClements, K. G.; Turnyanskiy, M. R.

    2017-01-01

    Some recent studies of energetic particles in laboratory, space and astrophysical plasmas are discussed, and a number of common themes identified. Such comparative studies can elucidate the underlying physical processes. For example microwave bursts observed during edge localised modes (ELMs) in the mega amp spherical tokamak (MAST) can be attributed to energetic electrons accelerated by parallel electric fields associated with the ELMs. The very large numbers of electrons known to be accelerated in solar flares must also arise from parallel electric fields, and the demonstration of energetic electron production during ELMs suggests close links at the kinetic level between ELMs and flares. Energetic particle studies in solar flares have focussed largely on electrons rather than ions, since bremsstrahlung from deka-keV electrons provides the best available explanation of flare hard x-ray emission. However ion acceleration (but not electron acceleration) has been observed during merging startup of plasmas in MAST with dimensionless parameters similar to those of the solar corona during flares. Recent measurements in the Earth’s radiation belts demonstrate clearly a direct link between ion cyclotron emission (ICE) and fast particle population inversion, supporting the hypothesis that ICE in tokamaks is driven by fast particle distributions of this type. Shear Alfvén waves in plasmas with beta less than the electron to ion mass ratio have a parallel electric field that, in the solar corona, could accelerate electrons to hard x-ray-emitting energies; an extension of this calculation to plasmas with Alfvén speed arbitrarily close to the speed of light suggests that the mechanism could play a role in the production of cosmic ray electrons.

  17. Near Earth space plasma monitoring under COST 296

    Directory of Open Access Journals (Sweden)

    Jürgen Bremer

    2009-06-01

    Full Text Available

    This review paper presents the main achievements of the near Earth space plasma monitoring under COST 296

    Action. The outputs of the COST 296 community making data, historical and real-time, standardized and available to the ionospheric community for their research, applications and modeling purposes are presented. The contribution of COST 296 with the added value of the validated data made possible a trusted ionospheric monitoring for research and modeling purposes, and it served for testing and improving the algorithms producing real-time

    data and providing data users measurement uncertainties. These value added data also served for calibration and

    validation of space-borne sensors. New techniques and parameters have been developed for monitoring the near Earth space plasma, as time dependent 2D maps of vertical total electron content (vTEC, other key ionospheric parameters and activity indices for distinguishing disturbed ionospheric conditions, as well as a technique for improving the discrepancies of different mapping services. The dissemination of the above products has been developed by COST 296 participants throughout the websites making them available on-line for real-time applications.


  18. Measurements of Plasma Potential Distribution in Segmented Electrode Hall Thruster

    Energy Technology Data Exchange (ETDEWEB)

    Y. Raitses; D. Staack; N.J. Fisch

    2001-10-16

    Use of a segmented electrode placed at the Hall thruster exit can substantially reduce the voltage potential drop in the fringing magnetic field outside the thruster channel. In this paper, we investigate the dependence of this effect on thruster operating conditions and segmented electrode configuration. A fast movable emissive probe is used to measure plasma potential in a 1 kW laboratory Hall thruster with semented electrodes made of a graphite material. Relatively small probe-induced perturbations of the thruster discharge in the vicinity of the thruster exit allow a reasonable comparison of the measured results for different thruster configurations. It is shown that the plasma potential distribution is almost not sensitive to changes of the electrode potential, but depends on the magnetic field distribution and the electrode placement.

  19. Magnetic fluctuations in anisotropic space plasmas: The effect of the plasma environment

    Science.gov (United States)

    Valdivia, J. A.; Toledo, B. A.; Gallo, N.; Muñoz, V.; Rogan, J.; Stepanova, M.; Moya, P. S.; Navarro, R. E.; Viñas, A. F.; Araneda, J.; López, R. A.; Díaz, M.

    2016-11-01

    The observations in the solar wind, which are usually organized in a beta-anisotropy diagram, seem to be constrained by linear instability thresholds. Unexpectedly, under these quasi-stable conditions, there is a finite level of electromagnetic fluctuations. A relevant component of these fluctuations can be understood in terms of the electromagnetic fields produced by the thermal motion of the charged particles. For the simple case of parallel propagating fields in an electron-proton plasma, we study the effect of the parameter ωpp /Ωc that characterizes the different space physics environments, and can affect the continuum spectrum produced by these fluctuations, which in turn may be used to understand the relevance of these processes occurring in a specific plasma environment.

  20. Design and construction of Keda Space Plasma Experiment (KSPEX) for the investigation of the boundary layer processes of ionospheric depletions.

    Science.gov (United States)

    Liu, Yu; Zhang, Zhongkai; Lei, Jiuhou; Cao, Jinxiang; Yu, Pengcheng; Zhang, Xiao; Xu, Liang; Zhao, Yaodong

    2016-09-01

    In this work, the design and construction of the Keda Space Plasma EXperiment (KSPEX), which aims to study the boundary layer processes of ionospheric depletions, are described in detail. The device is composed of three stainless-steel sections: two source chambers at both ends and an experimental chamber in the center. KSPEX is a steady state experimental device, in which hot filament arrays are used to produce plasmas in the two sources. A Macor-mesh design is adopted to adjust the plasma density and potential difference between the two plasmas, which creates a boundary layer with a controllable electron density gradient and inhomogeneous radial electric field. In addition, attachment chemicals can be released into the plasmas through a tailor-made needle valve which leads to the generation of negative ions plasmas. Ionospheric depletions can be modeled and simulated using KSPEX, and many micro-physical processes of the formation and evolution of an ionospheric depletion can be experimentally studied.

  1. Design and construction of Keda Space Plasma Experiment (KSPEX) for the investigation of the boundary layer processes of ionospheric depletions

    Science.gov (United States)

    Liu, Yu; Zhang, Zhongkai; Lei, Jiuhou; Cao, Jinxiang; Yu, Pengcheng; Zhang, Xiao; Xu, Liang; Zhao, Yaodong

    2016-09-01

    In this work, the design and construction of the Keda Space Plasma EXperiment (KSPEX), which aims to study the boundary layer processes of ionospheric depletions, are described in detail. The device is composed of three stainless-steel sections: two source chambers at both ends and an experimental chamber in the center. KSPEX is a steady state experimental device, in which hot filament arrays are used to produce plasmas in the two sources. A Macor-mesh design is adopted to adjust the plasma density and potential difference between the two plasmas, which creates a boundary layer with a controllable electron density gradient and inhomogeneous radial electric field. In addition, attachment chemicals can be released into the plasmas through a tailor-made needle valve which leads to the generation of negative ions plasmas. Ionospheric depletions can be modeled and simulated using KSPEX, and many micro-physical processes of the formation and evolution of an ionospheric depletion can be experimentally studied.

  2. New technology innovations with potential for space applications

    Science.gov (United States)

    Krishen, Kumar

    2008-07-01

    Human exploration and development of space is being pursued by spacefaring nations to explore, use, and enable the development of space and expand the human experience there. The goals include: increasing human knowledge of nature's processes using the space environment; exploring and settling the solar system; achieving routine space travel; and enriching life on Earth through living and working in space. A crucial aspect of future space missions is the development of infrastructure to optimize safety, productivity, and costs. A major component of mission execution is operations management. NASA's International Space Station is providing extensive experience in both infrastructure and operations. In view of this, a vigorously organized approach is needed to implement successful space-, planet-, and ground-based research and operations that entails wise and efficient use of technical and human resources. Many revolutionary technologies being pursued by researchers and technologists may be vital in making space missions safe, reliable, cost-effective, and productive. These include: ionic polymer-metal composite technology; solid-state lasers; time-domain sensors and communication systems; high-temperature superconductivity; nanotechnology; variable specific impulse magneto plasma rocket; fuzzy logic; wavelet technology; and neural networks. An overview of some of these will be presented, along with their application to space missions.

  3. Monte Carlo simulations of ionization potential depression in dense plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Stransky, M., E-mail: stransky@fzu.cz [Department of Radiation and Chemical Physics, Institute of Physics ASCR, Na Slovance 2, 182 21 Prague 8 (Czech Republic)

    2016-01-15

    A particle-particle grand canonical Monte Carlo model with Coulomb pair potential interaction was used to simulate modification of ionization potentials by electrostatic microfields. The Barnes-Hut tree algorithm [J. Barnes and P. Hut, Nature 324, 446 (1986)] was used to speed up calculations of electric potential. Atomic levels were approximated to be independent of the microfields as was assumed in the original paper by Ecker and Kröll [Phys. Fluids 6, 62 (1963)]; however, the available levels were limited by the corresponding mean inter-particle distance. The code was tested on hydrogen and dense aluminum plasmas. The amount of depression was up to 50% higher in the Debye-Hückel regime for hydrogen plasmas, in the high density limit, reasonable agreement was found with the Ecker-Kröll model for hydrogen plasmas and with the Stewart-Pyatt model [J. Stewart and K. Pyatt, Jr., Astrophys. J. 144, 1203 (1966)] for aluminum plasmas. Our 3D code is an improvement over the spherically symmetric simplifications of the Ecker-Kröll and Stewart-Pyatt models and is also not limited to high atomic numbers as is the underlying Thomas-Fermi model used in the Stewart-Pyatt model.

  4. Potential renovascular hypertension, space missions, and the role of magnesium

    Directory of Open Access Journals (Sweden)

    William J Rowe

    2009-11-01

    Full Text Available William J RoweFormer Assistant Clinical Professor of Medicine, Medical University of Ohio at Toledo, Keswick, VA, USAAbstract: Space flight (SF and dust inhalation in habitats cause hypertension whereas in SF (alone there is no consistent hypertension but reduced diurnal blood pressure (BP variation instead. Current pharmaceutical subcutaneous delivery systems are inadequate and there is impairment in the absorption, metabolism, excretion, and deterioration of some pharmaceuticals. Data obtained from the National Aeronautics and Space Administration through the Freedom of Information Act shows that Irwin returned from his 12-day Apollo 15 mission in 1971 and was administered a bicycle stress test. With just three minutes of exercise, his BP was >275/125 mm Hg (heart rate of only 130 beats per minute. There was no acute renal insult. Irwin’s apparent spontaneous remission is suggested to be related to the increase of a protective vasodilator, and his atrial natriuretic peptide (ANP reduced with SF because of reduced plasma volume. With invariable malabsorption and loss of bone/muscle storage sites, there are significant (P < 0.0001 reductions of magnesium (Mg required for ANP synthesis and release. Reductions of Mg and ANP can trigger pronounced angiotensin (200%, endothelin, and catecholamine elevations (clearly shown in recent years and vicious cycles between the latter and Mg deficits. There is proteinuria, elevated creatinine, and reduced renal concentrating ability with the potential for progressive inflammatory and oxidative stress-induced renal disease and hypertension with vicious cycles. After SF, animals show myocardial endothelial injuries and increased vascular resistance of extremities in humans. Even without dust, hypertension might eventually develop from renovascular hypertension during very long missions. Without sufficient endothelial protection from pharmaceuticals, a comprehensive gene research program should begin now

  5. Effective potential kinetic theory for strongly coupled plasmas

    Science.gov (United States)

    Baalrud, Scott D.; Daligault, Jérôme

    2016-11-01

    The effective potential theory (EPT) is a recently proposed method for extending traditional plasma kinetic and transport theory into the strongly coupled regime. Validation from experiments and molecular dynamics simulations have shown it to be accurate up to the onset of liquid-like correlation parameters (corresponding to Γ ≃ 10-50 for the one-component plasma, depending on the process of interest). Here, this theory is briefly reviewed along with comparisons between the theory and molecular dynamics simulations for self-diffusivity and viscosity of the one-component plasma. A number of new results are also provided, including calculations of friction coefficients, energy exchange rates, stopping power, and mobility. The theory is also cast in the Landau and Fokker-Planck kinetic forms, which may prove useful for enabling efficient kinetic computations.

  6. Magnetic Null Points in Kinetic Simulations of Space Plasmas

    Science.gov (United States)

    Olshevsky, Vyacheslav; Deca, Jan; Divin, Andrey; Peng, Ivy Bo; Markidis, Stefano; Innocenti, Maria Elena; Cazzola, Emanuele; Lapenta, Giovanni

    2016-03-01

    We present a systematic attempt to study magnetic null points and the associated magnetic energy conversion in kinetic particle-in-cell simulations of various plasma configurations. We address three-dimensional simulations performed with the semi-implicit kinetic electromagnetic code iPic3D in different setups: variations of a Harris current sheet, dipolar and quadrupolar magnetospheres interacting with the solar wind, and a relaxing turbulent configuration with multiple null points. Spiral nulls are more likely created in space plasmas: in all our simulations except lunar magnetic anomaly (LMA) and quadrupolar mini-magnetosphere the number of spiral nulls prevails over the number of radial nulls by a factor of 3-9. We show that often magnetic nulls do not indicate the regions of intensive energy dissipation. Energy dissipation events caused by topological bifurcations at radial nulls are rather rare and short-lived. The so-called X-lines formed by the radial nulls in the Harris current sheet and LMA simulations are rather stable and do not exhibit any energy dissipation. Energy dissipation is more powerful in the vicinity of spiral nulls enclosed by magnetic flux ropes with strong currents at their axes (their cross sections resemble 2D magnetic islands). These null lines reminiscent of Z-pinches efficiently dissipate magnetic energy due to secondary instabilities such as the two-stream or kinking instability, accompanied by changes in magnetic topology. Current enhancements accompanied by spiral nulls may signal magnetic energy conversion sites in the observational data.

  7. Magnetic null points in kinetic simulations of space plasmas

    CERN Document Server

    Olshevsky, Vyacheslav; Divin, Andrey; Peng, Ivy Bo; Markidis, Stefano; Innocenti, Maria Elena; Cazzola, Emanuele; Lapenta, Giovanni

    2015-01-01

    We present a systematic attempt to study magnetic null points and the associated magnetic energy conversion in kinetic Particle-in-Cell simulations of various plasma configurations. We address three-dimensional simulations performed with the semi-implicit kinetic electromagnetic code iPic3D in different setups: variations of a Harris current sheet, dipolar and quadrupolar magnetospheres interacting with the solar wind; and a relaxing turbulent configuration with multiple null points. Spiral nulls are more likely created in space plasmas: in all our simulations except lunar magnetic anomaly and quadrupolar mini-magnetosphere the number of spiral nulls prevails over the number of radial nulls by a factor of 3-9. We show that often magnetic nulls do not indicate the regions of intensive energy dissipation. Energy dissipation events caused by topological bifurcations at radial nulls are rather rare and short-lived. The so-called X-lines formed by the radial nulls in the Harris current sheet and lunar magnetic ano...

  8. A Plasma Aerocapture and Entry System for Manned Missions and Planetary Deep Space Orbiters Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Plasma Magnetoshell is based on demonstrated experimental results and the successful implementation would dramatically decrease mission risk, launch cost, mass,...

  9. Fundamental Study of Interactions Between High-Density Pulsed Plasmas and Materials for Space Propulsion

    Science.gov (United States)

    2012-09-01

    interactions studies (plasma too cold and too “dirty.”) We have built and tested a new, gas -fed, non- ablative, rep-rated capillary plasma source for our...those encountered in space propulsion devices including Pulsed Plasma Thrusters (PPT), Magneto-Plasma Dynamic (MPD) thrusters and capillary plasma...based thrusters . The ongoing research work brings together a team of researchers from the University of Texas at Austin (UT) and the University of

  10. Potential anesthesia protocols for space exploration missions.

    Science.gov (United States)

    Komorowski, Matthieu; Watkins, Sharmila D; Lebuffe, Gilles; Clark, Jonathan B

    2013-03-01

    In spaceflight beyond low Earth's orbit, medical conditions requiring surgery are of a high level of concern because of their potential impact on crew health and mission success. Whereas surgical techniques have been thoroughly studied in spaceflight analogues, the research focusing on anesthesia is limited. To provide safe anesthesia during an exploration mission will be a highly challenging task. The research objective is thus to describe specific anesthesia procedures enabling treatment of pre-identified surgical conditions. Among the medical conditions considered by the NASA Human Research Program Exploration Medical Capability element, those potentially necessitating anesthesia techniques have been identified. The most appropriate procedure for each condition is thoroughly discussed. The substantial cost of training time necessary to implement regional anesthesia is pointed out. Within general anesthetics, ketamine combines the unique advantages of preservation of cardiovascular stability, the protective airway reflexes, and spontaneous ventilation. Ketamine side effects have for decades tempered enthusiasm for its use, but recent developments in mitigation means broadened its indications. The extensive experience gathered in remote environments, with minimal equipment and occasionally by insufficiently trained care providers, confirms its high degree of safety. Two ketamine-based anesthesia protocols are described with their corresponding indications. They have been designed taking into account the physiological changes occurring in microgravity and the specific constraints of exploration missions. This investigation could not only improve surgical care during long-duration spaceflights, but may find a number of terrestrial applications in isolated or austere environments.

  11. Reduction in plasma potential by applying negative DC cathode bias in RF magnetron sputtering

    Science.gov (United States)

    Isomura, Masao; Yamada, Toshinori; Osuga, Kosuke; Shindo, Haruo

    2016-11-01

    We applied a negative DC bias voltage to the cathode of an RF magnetron sputtering system and successfully reduced the plasma potential in both argon plasma and hydrogen-diluted argon plasma. The crystallinity of the deposited Ge films is improved by increasing the negative DC bias voltage. It is indicated that the reduction in plasma potential is effective for reducing the plasma damage on deposited materials, caused by the electric potential between the plasma and substrates. In addition, the deposition rate is increased by the increased electric potential between the plasma and the cathode owing to the negative DC bias voltage. The present method successfully gives us higher speed and lower damage sputtering deposition. The increased electric potential between the plasma and the cathode suppresses the evacuation of electrons from the plasma and also enhances the generation of secondary electrons on the cathode. These probably suppress the electron loss from the plasma and result in the reduction in plasma potential.

  12. A Vlasov equation with Dirac potential used in fusion plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Bardos, Claude [Universite Paris-Diderot, Laboratoire J.-L. Lions, BP187, 4 Place Jussieu, 75252 Paris Cedex 05 (France); Nouri, Anne [Laboratoire d' Analyse, Topologie et Probabilites (UMR 6632), Aix-Marseille Universite, 39 Rue Joliot-Curie, 13453 Marseille Cedex 13 (France)

    2012-11-15

    Well-posedness of the Cauchy problem is analyzed for a singular Vlasov equation governing the evolution of the ionic distribution function of a quasineutral fusion plasma. The Penrose criterium is adapted to the linearized problem around a time and space homogeneous distribution function showing (due to the singularity) more drastic differences between stable and unstable situations. This pathology appears on the full nonlinear problem, well-posed locally in time with analytic initial data, but generally ill-posed in the Hadamard sense. Eventually with a very different class of solutions, mono-kinetic, which constrains the structure of the density distribution, the problem becomes locally in time well-posed.

  13. Effective polarization interaction potentials of the partially ionized dense plasma

    Energy Technology Data Exchange (ETDEWEB)

    Ramazanov, T S [IETP, Al Farabi Kazakh National University, Tole Bi 96a, 050012 Almaty (Kazakhstan); Dzhumagulova, K N [IETP, Al Farabi Kazakh National University, Tole Bi 96a, 050012 Almaty (Kazakhstan); Omarbakiyeva, Yu A [IETP, Al Farabi Kazakh National University, Tole Bi 96a, 050012 Almaty (Kazakhstan); Roepke, G [Institute of Physics, University of Rostock, D-18051 Rostock (Germany)

    2006-04-28

    The effective polarization interaction potential between charged and neutral particles is considered for a partially ionized plasma. This pseudopotential is deduced taking into account quantum-mechanical effects at short distances as well as screening effects at large distances. Furthermore, a cutoff radius is obtained using a modified effective-range theory. Explicit results for parameters describing the interaction of the atom with charged particles are given.

  14. Nonlinear ion-acoustic solitary waves with warm ions and non-Maxwellian electrons in space plasmas

    Science.gov (United States)

    Hussain Shah, Khalid; Qureshi, Nouman

    2017-04-01

    Electrons velocity distributions are often observed with non-Maxwellian features such flat tops at low energies and/or superthermal tails at high energies from different regions of near Earth plasmas such as Earth's bow shock, auroral zone and magnetosphere by numerous satellites. Such non-Maxwellian distributions are well modelled by generalized (r,q) distribution or Cairns distribution. Solitons are nonlinear solitary structures and are integral part of space plasmas. In this paper, we present a fluid model containing Cairns (r,q) distributed non-Maxwellian electrons and derive the Sagdeev potential for fully nonlinear fluid equations. We found that compressive solitons can be developed in such a plasma. The results from our model can be used to interpret solitary structures in space plasmas when electrons are obeying the non-Maxwellian flat tops along with the high energy tails.

  15. Effects of auroral potential drops on plasma sheet dynamics

    Science.gov (United States)

    Xi, Sheng; Lotko, William; Zhang, Binzheng; Wiltberger, Michael; Lyon, John

    2016-11-01

    The reaction of the magnetosphere-ionosphere system to dynamic auroral potential drops is investigated using the Lyon-Fedder-Mobarry global model including, for the first time in a global simulation, the dissipative load of field-aligned potential drops in the low-altitude boundary condition. This extra load reduces the field-aligned current (j||) supplied by nightside reconnection dynamos. The system adapts by forcing the nightside X line closer to Earth, with a corresponding reduction in current lensing (j||/B = constant) at the ionosphere and additional contraction of the plasma sheet during substorm recovery and steady magnetospheric convection. For steady and moderate solar wind driving and with constant ionospheric conductance, the cross polar cap potential and hemispheric field-aligned current are lower by approximately the ratio of the peak field-aligned potential drop to the cross polar cap potential (10-15%) when potential drops are included. Hemispheric ionospheric Joule dissipation is less by 8%, while the area-integrated, average work done on the fluid by the reconnecting magnetotail field increases by 50% within |y| < 8 RE. Effects on the nightside plasma sheet include (1) an average X line 4 RE closer to Earth; (2) a 12% higher mean reconnection rate; and (3) dawn-dusk asymmetry in reconnection with a 17% higher rate in the premidnight sector.

  16. Quantum potential and symmetries in extended phase space

    CERN Document Server

    Nasiri, S

    2005-01-01

    Here, we study the concept of the quantum potential using an extended phase space technique. It seems that, for a given potential, there exist an extended canonical transformation that removes the expression for quantum potential in dynamical equation. The situation, mathematically, is similar to the appearance of centrifugal potential in going from Cartesian to spherical coordinates that changes the physical potential to an effective one. As Examples, the cases of harmonic oscillator, particle in a box and hydrogen atom are worked out, where the quantum potential disappears from the Wigner equation as a possible representation of quantum mechanics in the phase space. This representation that keeps the Hamilton-Jacobi equation form invariant could be obtained by a particular extended canonical transformation on Sobouti-Nasiri equation in extended phase space.

  17. Winnicott and Arendt: bridging potential and political spaces.

    Science.gov (United States)

    LaMothe, Ryan

    2014-04-01

    In this article, the author seeks to bridge analytic theory, which is used as an interpretive framework to understand patients' psychic lives, and political philosophy, which accounts for individuals living a life in common as citizens. Specifically, I address how we can understand the relation between the psychosocial space of a parent(s) and child interaction, which becomes part of the child's psychic life, and the political space between and within citizens. The underlying claim is that there is a correlation between political space and the space between parent and child. I use an emended version of Donald Winnicott's concept of potential space and political philosopher Hannah Arendt's notion of the space of appearances to suggest connections between the consulting room and political space.

  18. Three-dimensional wake potential in a streaming dusty plasma

    Indian Academy of Sciences (India)

    M Salahuddin; M K Islam; A K Banerjee; M Salimullah; S K Ghosh

    2003-09-01

    The oscillatory wake potential for a slowly moving or static test dust particulate in a finite temperature, collisionless and unmagnetized dusty plasma with a continuous flow of ions and dust particles has been studied. The collective resonant interaction of the moving test particle with the low-frequency and low-phase-velocity dust-acoustic mode is the origin of the periodic attractive force between the like polarity particulates along and perpendicular to the streaming ions and dust grains resulting into dust-Coulomb crystal formation. This wake potential can explain the three-dimensional dust-Coulomb crystal formation in the laboratory conditions.

  19. MAGNETIC NULL POINTS IN KINETIC SIMULATIONS OF SPACE PLASMAS

    Energy Technology Data Exchange (ETDEWEB)

    Olshevsky, Vyacheslav; Innocenti, Maria Elena; Cazzola, Emanuele; Lapenta, Giovanni [Centre for Mathematical Plasma Astrophysics (CmPA), KU Leuven (Belgium); Deca, Jan [Laboratory for Atmospheric and Space Physics (LASP), University of Colorado Boulder, Boulder, CO (United States); Divin, Andrey [St. Petersburg State University, St. Petersburg (Russian Federation); Peng, Ivy Bo; Markidis, Stefano, E-mail: sya@mao.kiev.ua [High Performance Computing and Visualization (HPCViz), KTH Royal Institute of Technology, Stockholm (Sweden)

    2016-03-01

    We present a systematic attempt to study magnetic null points and the associated magnetic energy conversion in kinetic particle-in-cell simulations of various plasma configurations. We address three-dimensional simulations performed with the semi-implicit kinetic electromagnetic code iPic3D in different setups: variations of a Harris current sheet, dipolar and quadrupolar magnetospheres interacting with the solar wind, and a relaxing turbulent configuration with multiple null points. Spiral nulls are more likely created in space plasmas: in all our simulations except lunar magnetic anomaly (LMA) and quadrupolar mini-magnetosphere the number of spiral nulls prevails over the number of radial nulls by a factor of 3–9. We show that often magnetic nulls do not indicate the regions of intensive energy dissipation. Energy dissipation events caused by topological bifurcations at radial nulls are rather rare and short-lived. The so-called X-lines formed by the radial nulls in the Harris current sheet and LMA simulations are rather stable and do not exhibit any energy dissipation. Energy dissipation is more powerful in the vicinity of spiral nulls enclosed by magnetic flux ropes with strong currents at their axes (their cross sections resemble 2D magnetic islands). These null lines reminiscent of Z-pinches efficiently dissipate magnetic energy due to secondary instabilities such as the two-stream or kinking instability, accompanied by changes in magnetic topology. Current enhancements accompanied by spiral nulls may signal magnetic energy conversion sites in the observational data.

  20. Effect of Ambipolar Potential on the Propulsive Performance of the GDM Plasma Thruster Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The gasdynamic mirror (GDM) plasma thruster has the ability to confine high-density plasma for the length of time required to heat it to the temperatures...

  1. A thin column of dense plasma for space-charge neutralization of intense ion beams

    Science.gov (United States)

    Roy, P. K.; Seidl, P. A.; Anders, A.; Barnard, J. J.; Bieniosek, F. M.; Friedman, A.; Gilson, E. P.; Greenway, W.; Sefkow, A. B.; Jung, J. Y.; Leitner, M.; Lidia, S. M.; Logan, B. G.; Waldron, W. L.; Welch, D. R.

    2008-11-01

    Typical ion driven warm dense matter experiment requires a plasma density of 10^14/cm^3 to meet the challenge of np>nb, where np, and nb are the number densities of plasma and beam, respectively. Plasma electrons neutralize the space charge of an ion beam to allow a small spot of about 1-mm radius. In order to provide np>nb for initial warm, dense matter experiments, four cathodic arc plasma sources have been fabricated, and the aluminum plasma is focused in a focusing solenoid (8T field). A plasma probe with 37 collectors was developed to measure the radial plasma profile inside the solenoid. Results show that the plasma forms a thin column of diameter ˜7mm along the solenoid axis. The magnetic mirror effect, plasma condensation, and the deformation of the magnetic field due to eddy currents are under investigation. Data on plasma parameters and ion beam neutralization will be presented.

  2. Diagnosis of Magnetic Structures and Intermittency in Space Plasma Turbulence using the Method of Surrogate Data

    Science.gov (United States)

    Sahraoui, Fouad; Goldstein, Melvyn

    2008-01-01

    Several observations in space plasmas have reported the presence of coherent structures at different plasma scales. Structure formation is believed to be a direct consequence of nonlinear interactions between the plasma modes, which depend strongly on phase synchronization of those modes. Despite this important role of the phases in turbulence, very limited work has been however devoted to study the phases as a potential tracers of nonlinearities in comparison with the wealth of literature on power spectra of turbulence where phases are totally missed. We present a method based on surrogate data to systematically detect coherent structures in turbulent signals. The new method has been applied successfully to magnetosheath turbulence (Sahraoui, Phys. Rev. E, 2008, in press), where the relationship between the identified phase coherence and intermittency (classically identified as non Gaussian tails of the PDFs) as well as the energy cascade has been studied. Here we review the main results obtained in that study and show further applications to small scale solar wind turbulence. Implications of the results on theoretical modelling of space turbulence (applicability of weak/wave turbulence, its validity limits and its connection to intermittency) will be discussed.

  3. A Review of Nonlinear Low Frequency (LF) Wave Observations in Space Plasmas: On the Development of Plasma Turbulence

    Science.gov (United States)

    Tsurutani, Bruce T.

    1995-01-01

    As the lead-off presentation for the topic of nonlinear waves and their evolution, we will illustrate some prominent examples of waves in space plasmas. We will describe recent observations detected within planetary foreshocks, near comets and in interplanetary space. It is believed that the nonlinear LF plasma wave features discussed here are part of and may be basic to the development of plasma turbulence. In this sense, this is one area of space plasma physics that is fundamental, with applications to fusion physics and astrophysics as well. It is hoped that the reader(s) will be stimulated to study nonlinear wave development themselves, if he/she is not already involved.

  4. Statically screened ion potential and Bohm potential in a quantum plasma

    Energy Technology Data Exchange (ETDEWEB)

    Moldabekov, Zhandos [Institut für Theoretische Physik und Astrophysik, Christian-Albrechts-Universität zu Kiel, Leibnizstraße 15, 24098 Kiel (Germany); Institute for Experimental and Theoretical Physics, Al-Farabi Kazakh National University, 71 Al-Farabi Str., 050040 Almaty (Kazakhstan); Schoof, Tim; Ludwig, Patrick; Bonitz, Michael [Institut für Theoretische Physik und Astrophysik, Christian-Albrechts-Universität zu Kiel, Leibnizstraße 15, 24098 Kiel (Germany); Ramazanov, Tlekkabul [Institute for Experimental and Theoretical Physics, Al-Farabi Kazakh National University, 71 Al-Farabi Str., 050040 Almaty (Kazakhstan)

    2015-10-15

    The effective potential Φ of a classical ion in a weakly correlated quantum plasma in thermodynamic equilibrium at finite temperature is well described by the random phase approximation screened Coulomb potential. Additionally, collision effects can be included via a relaxation time ansatz (Mermin dielectric function). These potentials are used to study the quality of various statically screened potentials that were recently proposed by Shukla and Eliasson (SE) [Phys. Rev. Lett. 108, 165007 (2012)], Akbari-Moghanjoughi (AM) [Phys. Plasmas 22, 022103 (2015)], and Stanton and Murillo (SM) [Phys. Rev. E 91, 033104 (2015)] starting from quantum hydrodynamic (QHD) theory. Our analysis reveals that the SE potential is qualitatively different from the full potential, whereas the SM potential (at any temperature) and the AM potential (at zero temperature) are significantly more accurate. This confirms the correctness of the recently derived [Michta et al., Contrib. Plasma Phys. 55, 437 (2015)] pre-factor 1/9 in front of the Bohm term of QHD for fermions.

  5. Near Discharge Cathode Assembly Plasma Potential Measurements in a 30-cm NSTAR Type Ion Engine During Beam Extraction

    Science.gov (United States)

    Herman, Daniel A.; Gallimore, Alec D.

    2006-01-01

    Floating emissive probe plasma potential data are presented over a two-dimensional array of locations in the near Discharge Cathode Assembly (DCA) region of a 30-cm diameter ring-cusp ion thruster. Discharge plasma data are presented with beam extraction at throttling conditions comparable to the NASA TH Levels 8, 12, and 15. The operating conditions of the Extended Life Test (ELT) of the Deep Space One (DS1) flight spare ion engine, where anomalous discharge keeper erosion occurred, were TH 8 and TH 12 consequently they are of specific interest in investigating discharge keeper erosion phenomena. The data do not validate the presence of a potential hill plasma structure downstream of the DCA, which has been proposed as a possible erosion mechanism. The data are comparable in magnitude to data taken by other researchers in ring-cusp electron-bombardment ion thrusters. The plasma potential structures are insensitive to thruster throttling level with a minimum as low as 14 V measured at the DCA exit plane and increasing gradually in the axial direction. A sharp increase in plasma potential to the bulk discharge value of 26 to 28 volts, roughly 10 mm radially from DCA centerline, was observed. Plasma potential measurements indicate a low-potential plume structure that is roughly 20 mm in diameter emanating from the discharge cathode that may be attributed to a free-standing plasma double layer.

  6. A linear radio frequency plasma reactor for potential and current mapping in a magnetized plasma.

    Science.gov (United States)

    Faudot, E; Devaux, S; Moritz, J; Heuraux, S; Molina Cabrera, P; Brochard, F

    2015-06-01

    Langmuir probe measurements in front of high power ion cyclotron resonant frequency antennas are not possible or simply too noisy to be analyzed properly. A linear experiment is a radio frequency (RF) magnetized plasma discharge reactor designed to probe the rectified potential in front of such antennas but at low power level (1 kW) to next improve antenna design and mitigate sheath effects. The maximum magnetic field is 0.1 T, and the RF amplifier can work between 10 kHz and 250 MHz allowing ion cyclotron resonances for argon or helium. The first measurements with no magnetic field are presented here, especially 2D potential maps extracted from the RF compensated probe measurements yield ni ≈ 10(15) m(-3) and Te ≈ 2 eV for RF power lower than 100 W. Series resonances in the chamber are highlighted and allow to deduce the plasma parameters from a simple equivalent impedance model of the plasma in helium gas. Next studies will be focused on magnetized plasmas and especially magnetized RF sheaths.

  7. International Space Station (ISS) Plasma Contactor Unit (PCU) Utilization Plan Assessment Update

    Science.gov (United States)

    Hernandez-Pellerano, Amri; Iannello, Christopher J.; Garrett, Henry B.; Ging, Andrew T.; Katz, Ira; Keith, R. Lloyd; Minow, Joseph I.; Willis, Emily M.; Schneider, Todd A.; Whittlesey, Edward J.; Wollack, Edward J.; Wright, Kenneth H.

    2014-01-01

    The International Space Station (ISS) vehicle undergoes spacecraft charging as it interacts with Earth's ionosphere and magnetic field. The interaction can result in a large potential difference developing between the ISS metal chassis and the local ionosphere plasma environment. If an astronaut conducting extravehicular activities (EVA) is exposed to the potential difference, then a possible electrical shock hazard arises. The control of this hazard was addressed by a number of documents within the ISS Program (ISSP) including Catastrophic Safety Hazard for Astronauts on EVA (ISS-EVA-312-4A_revE). The safety hazard identified the risk for an astronaut to experience an electrical shock in the event an arc was generated on an extravehicular mobility unit (EMU) surface. A catastrophic safety hazard, by the ISS requirements, necessitates mitigation by a two-fault tolerant system of hazard controls. Traditionally, the plasma contactor units (PCUs) on the ISS have been used to limit the charging and serve as a "ground strap" between the ISS structure and the surrounding ionospheric plasma. In 2009, a previous NASA Engineering and Safety Center (NESC) team evaluated the PCU utilization plan (NESC Request #07-054-E) with the objective to assess whether leaving PCUs off during non-EVA time periods presented risk to the ISS through assembly completion. For this study, in situ measurements of ISS charging, covering the installation of three of the four photovoltaic arrays, and laboratory testing results provided key data to underpin the assessment. The conclusion stated, "there appears to be no significant risk of damage to critical equipment nor excessive ISS thermal coating damage as a result of eliminating PCU operations during non- EVA times." In 2013, the ISSP was presented with recommendations from Boeing Space Environments for the "Conditional" Marginalization of Plasma Hazard. These recommendations include a plan that would keep the PCUs off during EVAs when the

  8. Numerical Modeling and Analysis of Space-Based Electric Antennas via Plasma Particle Simulation

    Science.gov (United States)

    Miyake, Y.; Usui, H.; Kojima, H.

    2009-12-01

    Better understanding of electric antenna properties (e.g., impedance) in space plasma environment is necessitated, because calibration of electric field data obtained by scientific spacecraft should be done with precise knowledge about the properties. Particularly, a strong demand arises regarding a sophisticated method for evaluating modern electric field instrument properties toward future magnetospheric missions. However, due to complex behavior of surrounding plasmas, it is often difficult to apply theoretical approaches to the antenna analysis including the plasma kinetic effects and the complex structure of such instruments. For the self-consistent antenna analysis, we have developed a new electromagnetic (EM) particle simulation code named EMSES. The code is based on the particle-in-cell technique and also supports a treatment of inner boundaries describing spacecraft conductive surfaces. This enables us to naturally include the effects of the inhomogeneous plasma environment such as a plasma and photoelectron sheaths created around the antenna. The support of the full EM treatment is also important to apply our tool to antenna properties for not only electrostatic (ES) but also EM plasma waves. In the current study, we particularly focus on an electric field instrument MEFISTO, which is designed for BepiColombo/MMO to the Mercury orbit. For the practical analysis of MEFISTO electric properties, it is important to consider an ES environment affected by the instrument body potential and the photoelectron distribution. We present numerical simulations on an ES structure around MEFISTO as well as current-voltage characteristic of the instrument. We have also started numerical modeling of a photoelectron guard electrode, which is one of key technologies for producing an optimal condition of plasma environment around the instrument. We have modeled a pre-amplifier housing called “puck”, the surface of which functions as the electrode. The photoelectron guard

  9. Research in space science and technology. [including X-ray astronomy and interplanetary plasma physics

    Science.gov (United States)

    Beckley, L. E.

    1977-01-01

    Progress in various space flight research programs is reported. Emphasis is placed on X-ray astronomy and interplanetary plasma physics. Topics covered include: infrared astronomy, long base line interferometry, geological spectroscopy, space life science experiments, atmospheric physics, and space based materials and structures research. Analysis of galactic and extra-galactic X-ray data from the Small Astronomy Satellite (SAS-3) and HEAO-A and interplanetary plasma data for Mariner 10, Explorers 47 and 50, and Solrad is discussed.

  10. Plasma-potentiated small molecules—possible alternative to antibiotics?

    Science.gov (United States)

    Bazaka, Kateryna; Bazaka, Olha; Levchenko, Igor; Xu, Shuyan; Ivanova, Elena P.; Keidar, Michael; (Ken Ostrikov, Kostya

    2017-09-01

    The efficacy of the existing arsenal of antibiotics is continuously compromised by their indiscriminative and often excessive use. The antibiotic arsenal can be expanded with agents that have different mechanisms of activity to conventional drugs, such as plant-derived natural antimicrobial small molecules, yet these often lack sufficient activity and selectivity to fulfill the antibiotics requirements and conventional thermochemical methods of their transient activation may not be compatible with biomedical applications. Here, non-equilibrium conditions of atmospheric-pressure plasma are used for rapid, single-step potentiation of activity of select terpenes without the use of chemicals or heating. Substantial potentiation of activity against Staphylococcus aureus cells in planktonic and biofilm states is observed in both inherently antibacterial terpenes, e.g. terpinen-4-ol, and compounds generally considered to have limited effect against S. aureus, e.g. γ-terpinene. The improved biological activity may arise, at least in part, from the changes in the physico–chemical properties of the terpenes induced by plasma-generated chemical species and physical effects, such as electric fields and UV irradiation. This activation approach is generic, and thus can potentially be applied to other molecules and their mixtures in an effort to expand the range of effective antimicrobial agents for deactivation of pathogenic organisms in hygiene, medical and food applications.

  11. Multiscale, Intermittent, Turbulent Fluctuations in Space Plasmas and Their Influence on the Interscale Behavior of the Space Environment

    Science.gov (United States)

    2012-06-26

    Belgium Institute of Spatial Aeronomy and Center of Excellence in Solar-Terrestrial Physics, 2010. Invited Lectures: 1. Invited Lecturer, (ROMA...NM 87545, USA 4Belgian Institute for Space Aeronomy , 1180 Brussels, Belgium 5Institute for Space Sciences, 077125 Bucharest, Romania 6Plasma and

  12. Potential space applications of nanomaterials and standartization issues

    Science.gov (United States)

    Voronina, Ekaterina; Novikov, Lev

    Nanomaterials surpass traditional materials for space applications in many aspects due to their unique properties associated with nanoscale size of their constituents. This superiority in mechanical, thermal, electrical and optical properties will evidently inspire a wide range of applications in the next generation spacecraft intended for the long-term (~15-20 years) operation in near-Earth orbits and the automatic and manned interplanetary missions as well as in the construction of inhabited bases on the Moon. Nanocomposites with nanoclays, carbon nanotubes and various nanoparticles as fillers are one of the most promising materials for space applications. They may be used as light-weighted and strong structural materials as well as functional and smart materials of general and specific applications, e.g. thermal stabilization, radiation shielding, electrostatic charge mitigation, protection of atomic oxygen influence and space debris impact, etc. Currently, ISO activity on developing standards concerning different issues of nanomaterials manufacturing and applications is high enough. In this presentation, a brief review of existing standards and standards under development in this field is given. Most such standards are related to nanoparticles and nanotube production and characterization, thus the next important step in this activity is the creation of standards on nanomaterial properties and their behavior in different environmental conditions, including extreme environments. The near-Earth’s space is described as an extreme environment for materials due to high vacuum, space radiation, hot and cold plasma, micrometeoroids and space debris, temperature differences, etc. Existing experimental and theoretical data demonstrate that nanomaterials response to various space environment effects may differ substantially from the one of conventional bulk spacecraft materials. Therefore, it is necessary to determine the space environment components, critical for

  13. Realising the potential of shared space in facilities management

    DEFF Research Database (Denmark)

    Brinkø, Rikke

    of shared space, building towards a new method for efficient and sustainable facilities management operation of buildings and properties. The practical part is focused on connecting this new knowledge to practical applications and developing tools that can be used to work with shared spaces in a practice...... in general, as well as the work having gone in to the development of the typology, and combines it with a number of practical steps to be taken co-created with practitioners. Through this combination it presents a complete guide to working with shared space in a municipal real-estate portfolio, from...... identifying potential on a portfolio level to evaluating the final result after the space has been taken into use. Through the process of identifying these key aspects of shared space and the study of the intricate processes involved, three themes, territoriality, involvement and practicalities, were...

  14. Lubrication of space systems: Challenges and potential solutions

    Science.gov (United States)

    Fusaro, Robert L.

    1992-01-01

    Future space missions will all require advanced mechanical moving components which will require wear protection and lubrication. The tribology practices used today are primarily based upon a technology base that is more than 20 years old. This paper will discuss NASA's future space missions and some of the mechanism tribology challenges that will be encountered. Potential solutions to these challenges using coatings technology will be assessed.

  15. Drift Kelvin-Helmholtz instabilities in space plasmas

    Science.gov (United States)

    Sharma, Avadhesh C.; Srivastava, Krishna M.

    1992-01-01

    Drift Kelvin-Helmholtz instabilities of a finite-beta plasma in equilibrium electric and magnetic fields which are perpendicular to each other are studied using two fluid equations. Three types of these instabilities are considered including the magnetosonic instability of a finite beta-homogeneous plasma, the electrostatic drift instability of an inhomogeneous low-beta plasma, and the magneto-acoustic instability of a high-beta inhomogeneous isothermal plasma. It is shown that the electric field has either stabilizing or destabilizing effect depending on conditions under consideration.

  16. Space Resource Utilization: Technologies and Potential Synergism with Terrestrial Mining

    Science.gov (United States)

    Sanders, Gerald B.

    2015-01-01

    Space Resources and Their Uses: The idea of using resources in space to support human exploration and settlement or for economic development and profit beyond the surface of Earth has been proposed and discussed for decades. Work on developing a method to extract oxygen from lunar regolith started even before humans set foot on the Moon for the first time. The use of space resources, commonly referred to as In Situ Resource Utilization (ISRU), involves the processes and operations to harness and utilize resources in space (both natural and discarded) to create products for subsequent use. Potential space resources include water, solar wind implanted volatiles (hydrogen, helium, carbon, nitrogen, etc.), vast quantities of metals and minerals in extraterrestrial soils, atmospheric constituents, unlimited solar energy, regions of permanent light and darkness, the vacuum and zero-gravity of space itself, trash and waste from human crew activities, and discarded hardware that has completed its primary purpose. ISRU covers a wide variety of concepts, technical disciplines, technologies, and processes. When considering all aspects of ISRU, there are 5 main areas that are relevant to human space exploration and the commercialization of space: 1. Resource Characterization and Mapping, 2. In Situ Consumables Production, 3. Civil Engineering and Construction, 4. In Situ Energy Production and Storage, and 5. In Situ Manufacturing.

  17. Leucine-based receptor sorting motifs are dependent on the spacing relative to the plasma membrane

    DEFF Research Database (Denmark)

    Geisler, C; Dietrich, J; Nielsen, B L;

    1998-01-01

    amino acid, is constitutively active. In this study, we have investigated how the spacing relative to the plasma membrane affects the function of both types of leucine-based motifs. For phosphorylation-dependent leucine-based motifs, a minimal spacing of 7 residues between the plasma membrane...... and the phospho-acceptor was required for phosphorylation and thereby activation of the motifs. For constitutively active leucine-based motifs, a minimal spacing of 6 residues between the plasma membrane and the acidic residue was required for optimal activity of the motifs. In addition, we found that the acidic...

  18. Designing Difference: Co-Production of Spaces of Potentiality

    Directory of Open Access Journals (Sweden)

    Garrett Wolf

    2016-03-01

    Full Text Available Design and Planning professionals have long been influenced by the belief in physically and spatially deterministic power over people and the environment, a belief that their representations of space become space. As a result the goal of design often becomes “fixing” or directing behavior and culture instead of letting culture happen. This outlook often prevents designers from engaging critically with culture, through representational space and spatial practice, as a crucial, possibly the most crucial, aspect in the design process. Just as human cultures interact to constantly reproduce and co-produce hybrid cultures, the professional designer and those users and experiencers of design (at whatever scale must interact to co-produce spaces and places of activity. Through a critique of the practice of placemaking, we highlight the need to differentiate between participation and co-production. Understanding participation as one element of the design process and the role of design at larger scales of co-productive processes can help designers have a better understanding of how spaces are produced, and the role of designers in the creation of spaces of potentiality. Agamben’s writing on potentialities and Lefebvre’s spatial triad offer a theoretical framework to investigate the ethical role of professional designers in society while taking a critical stance against the singular solutions of modernist urban transformation. Spaces of Potentiality are seen here as a designer’s simultaneous withdrawal from rational problem solving and deterministic solutions, and an engagement with open source strategies for the co-production of urban space.

  19. Misestimation of temperature when applying Maxwellian distributions to space plasmas described by kappa distributions

    CERN Document Server

    Nicolaou, Georgios

    2016-01-01

    This paper presents the misestimation of temperature when observations from a kappa distributed plasma are analyzed as a Maxwellian. One common method to calculate the space plasma parameters is by fitting the observed distributions using known analytical forms. More often, the distribution function is included in a forward model of the instrument's response, which is used to reproduce the observed energy spectrograms for a given set of plasma parameters. In both cases, the modeled plasma distribution fits the measurements to estimate the plasma parameters. The distribution function is often considered to be Maxwellian even though in many cases the plasma is better described by a kappa distribution. In this work we show that if the plasma is described by a kappa distribution, the derived temperature assuming Maxwell distribution can be significantly off. More specifically, we derive the plasma temperature by fitting a Maxwell distribution to pseudo-data produced by a kappa distribution, and then examine the d...

  20. Holographic dual of a boost-invariant plasma with chemical potential

    Energy Technology Data Exchange (ETDEWEB)

    Kalaydzhyan, Tigran; Kirsch, Ingo

    2010-12-15

    We construct a gravity dual of a boost-invariant flow of an N=4 SU(N) supersymmetric Yang-Mills gauge theory plasma with chemical potential. We present both a first-order corrected late-time solution in Eddington-Finkelstein coordinates and a zeroth-order solution in parametric form in Fefferman-Graham coordinates. The resulting background takes the form of a time-dependent AdS Reissner-Nordstroem-type black hole whose horizons move into the bulk of the AdS space. The solution correctly reproduces the energy and charge density as well as the viscosity of the plasma previously computed in the literature. (orig.)

  1. Consistency of Scalar Potentials from Quantum de Sitter Space

    CERN Document Server

    Espinosa, José R; Trépanier, Maxime

    2015-01-01

    We derive constraints on the scalar potential of a quantum field theory in de Sitter space. The constraints, which we argue should be understood as consistency conditions for quantum field theories in dS space, originate from a consistent interpretation of quantum de Sitter space through its Coleman-De Luccia tunneling rate. Indeed, consistency of de Sitter space as a quantum theory of gravity with a finite number of degrees of freedom suggests the tunneling rates to vacua with negative cosmological constants be interpreted as Poincar\\'e recurrences. Demanding the tunneling rate to be a Poincar\\'e recurrence imposes two constraints, or consistency conditions, on the scalar potential. Although the exact consistency conditions depend on the shape of the scalar potential, generically they correspond to: the distance in field space between the de Sitter vacuum and any other vacuum with negative cosmological constant must be of the order of the reduced Planck mass or larger; and the fourth root of the vacuum energ...

  2. Potential large missions enabled by NASA's space launch system

    Science.gov (United States)

    Stahl, H. Philip; Hopkins, Randall C.; Schnell, Andrew; Smith, David A.; Jackman, Angela; Warfield, Keith R.

    2016-07-01

    Large space telescope missions have always been limited by their launch vehicle's mass and volume capacities. The Hubble Space Telescope (HST) was specifically designed to fit inside the Space Shuttle and the James Webb Space Telescope (JWST) is specifically designed to fit inside an Ariane 5. Astrophysicists desire even larger space telescopes. NASA's "Enduring Quests Daring Visions" report calls for an 8- to 16-m Large UV-Optical-IR (LUVOIR) Surveyor mission to enable ultra-high-contrast spectroscopy and coronagraphy. AURA's "From Cosmic Birth to Living Earth" report calls for a 12-m class High-Definition Space Telescope to pursue transformational scientific discoveries. NASA's "Planning for the 2020 Decadal Survey" calls for a Habitable Exoplanet Imaging (HabEx) and a LUVOIR as well as Far-IR and an X-Ray Surveyor missions. Packaging larger space telescopes into existing launch vehicles is a significant engineering complexity challenge that drives cost and risk. NASA's planned Space Launch System (SLS), with its 8 or 10-m diameter fairings and ability to deliver 35 to 45-mt of payload to Sun-Earth-Lagrange-2, mitigates this challenge by fundamentally changing the design paradigm for large space telescopes. This paper reviews the mass and volume capacities of the planned SLS, discusses potential implications of these capacities for designing large space telescope missions, and gives three specific mission concept implementation examples: a 4-m monolithic off-axis telescope, an 8-m monolithic on-axis telescope and a 12-m segmented on-axis telescope.

  3. The Potential for Space Intervention in Global Catastrophes

    Science.gov (United States)

    Hempsell, M.

    There is a growing understanding of the risks facing mankind of global catastrophe, which is defined as an event that kills a quarter the world population and risks destruction of organised society. Such catastrophes can be triggered by either naturally occurring, or arthropogenic, initiating events. And history shows that catastrophes with a natural origin do occur, with a mean separation time of around 1000 years. Anthropogenic initiated events are a recent possibility resulting from an expansion of technology capabilities, economic activity and population and, while they clearly significantly increase the total risk level above the natural background, it is more difficult to determine quantitatively by how much. Some initiating events and be directly tackled by an appropriate space capability. For example intercepting Near Earth Object before collision, or using Solar Power Satellites to eliminating carbon dioxide production in the power generation process to which many attribute global warming. Obviously prevention is the preferred option and so, not surprisingly, these particular uses of space as a means of preventing global catastrophe have received considerable attention. However space capability has a much wider potential for intervention in global catastrophes, even in those where the initiating event itself cannot be prevented. Previous work highlighting the risks through consideration of historic catastrophes has identified that global catastrophes have a complex structure with the initiating event triggering chains of vectors, which in turn trigger death causing agents. The work also highlighted that the vectors and agents during a catastrophe are similar regardless of the initiating event. This opens the possibility that space systems capable of addressing generic vectors and agents on a global scale can help deal with any global catastrophe regardless of its cause. The paper lists known (and credible) components to global catastrophes and highlight

  4. Technical issues in the conduct of large space platform experiments in plasma physics and geoplasma sciences

    Science.gov (United States)

    Szuszczewicz, Edward P.

    1986-01-01

    Large, permanently-manned space platforms can provide exciting opportunities for discoveries in basic plasma and geoplasma sciences. The potential for these discoveries will depend very critically on the properties of the platform, its subsystems, and their abilities to fulfill a spectrum of scientific requirements. With this in mind, the planning of space station research initiatives and the development of attendant platform engineering should allow for the identification of critical science and technology issues that must be clarified far in advance of space station program implementation. An attempt is made to contribute to that process, with a perspective that looks to the development of the space station as a permanently-manned Spaceborne Ionospheric Weather Station. The development of this concept requires a synergism of science and technology which leads to several critical design issues. To explore the identification of these issues, the development of the concept of an Ionospheric Weather Station will necessarily touch upon a number of diverse areas. These areas are discussed.

  5. Multi-MW Closed Cycle MHD Nuclear Space Power Via Nonequilibrium He/Xe Working Plasma

    Science.gov (United States)

    Litchford, Ron J.; Harada, Nobuhiro

    2011-01-01

    Prospects for a low specific mass multi-megawatt nuclear space power plant were examined assuming closed cycle coupling of a high-temperature fission reactor with magnetohydrodynamic (MHD) energy conversion and utilization of a nonequilibrium helium/xenon frozen inert plasma (FIP). Critical evaluation of performance attributes and specific mass characteristics was based on a comprehensive systems analysis assuming a reactor operating temperature of 1800 K for a range of subsystem mass properties. Total plant efficiency was expected to be 55.2% including plasma pre-ionization power, and the effects of compressor stage number, regenerator efficiency and radiation cooler temperature on plant efficiency were assessed. Optimal specific mass characteristics were found to be dependent on overall power plant scale with 3 kg/kWe being potentially achievable at a net electrical power output of 1-MWe. This figure drops to less than 2 kg/kWe when power output exceeds 3 MWe. Key technical issues include identification of effective methods for non-equilibrium pre-ionization and achievement of frozen inert plasma conditions within the MHD generator channel. A three-phase research and development strategy is proposed encompassing Phase-I Proof of Principle Experiments, a Phase-II Subscale Power Generation Experiment, and a Phase-III Closed-Loop Prototypical Laboratory Demonstration Test.

  6. Chiral potential renormalized in harmonic-oscillator space

    CERN Document Server

    Yang, C -J

    2016-01-01

    We renormalize the chiral effective field theory (EFT) potential in harmonic-oscillator (HO) model space. The low energy constants (LECs) are utilized to absorb not just the ultra-violet part of the physics due to the cutoff, but also the infrared part due to the truncation of model space. We use the inverse J-matrix method to reproduce the nucleon-nucleon (NN) scattering phase shifts in the given model space. We demonstrate that by including the NLO correction, the nucleon-nucleon scattering in the continuum could be well reproduced in the truncated HO trap space up to laboratory energy $T_{lab}=100$ MeV with number of HO basis $n_{max}$ as small as 10. A perturbative power counting starts at subleading order is adopted in this work, and how to extract the perturbative contribution is demonstrated. Our work serves as the input to perform ab-initio calculations.

  7. A potential foundation for emergent space-time

    Science.gov (United States)

    Knuth, Kevin H.; Bahreyni, Newshaw

    2014-11-01

    We present a novel derivation of both the Minkowski metric and Lorentz transformations from the consistent quantification of a causally ordered set of events with respect to an embedded observer. Unlike past derivations, which have relied on assumptions such as the existence of a 4-dimensional manifold, symmetries of space-time, or the constant speed of light, we demonstrate that these now familiar mathematics can be derived as the unique means to consistently quantify a network of events. This suggests that space-time need not be physical, but instead the mathematics of space and time emerges as the unique way in which an observer can consistently quantify events and their relationships to one another. The result is a potential foundation for emergent space-time.

  8. To Boldly Go: America's Next Era in Space. The Plasma Universe

    Science.gov (United States)

    2004-01-01

    Dr. France Cordova, NASA's Chief Scientist, chaired this, the eighth seminar in the Administrator's Seminar Series. She introduced the NASA Administrator, Daniel S. Goldin, who, in turn, introduced the subject of plasma. Plasma, an ionized gas, is a function of temperature and density. We ve learned that, at Jupiter, the radiation is dense. But, Goldin asked, what else do we know? Dr. Cordova then introduced Dr. James Van Allen, for whom the Van Allen radiation belt was named. Dr. Van Allen, a member of the University of Iowa faculty, discussed the growing interest in practical applications of space physics, including radiation fields and particles, plasmas and ionospheres. He listed a hierarchy of magnetic fields, beginning at the top, as pulsars, the Sun, planets, interplanetary medium, and interstellar medium. He pointed out that we have investigated eight of the nine known planets,. He listed three basic energy sources as 1) kinetic energy from flowing plasma such as constitutional solar wind or interstellar wind; 2) rotational energy of the planet, and 3) orbital energy of satellites. He believes there are seven sources of energetic particles and five potential places where particles may go. The next speaker, Dr. Ian Axford of New Zealand, has been associated with the Max Planck Institut fuer Aeronomie and plasma physics. He has studied solar and galactic winds and clusters of galaxies of which there are several thousand. He believes that the solar wind temperature is in the millions of degrees. The final speaker was Dr. Roger Blanford of the California Institute of Technology. He classified extreme plasmas as lab plasmas and cosmic plasmas. Cosmic plasmas are from supernovae remnants. These have supplied us with heavy elements and may come via a shock front of 10(sup 15) electron volts. To understand the physics of plasma, one must learn about x-rays, the maximum energy of acceleration by supernova remnants, particle acceleration and composition of cosmic

  9. The distribution of radio plasma in time and space.

    Science.gov (United States)

    Blundell, Katherine M

    2005-03-15

    The influence of jet-ejected plasma has been an important theme of this meeting; I draw attention to the prevalence of jet-ejected plasma, in particular that which has not been properly accounted for in the past. There are three strands to this paper: important emission which is prominent only at the lowest radio frequencies; relic radio plasma which must exist if even the most basic aspects of radio source evolutionary models are correct; and evidence that some 'radio-quiet' quasars could be FR-I radio sources.

  10. Phase-space diffusion in turbulent plasmas: The random acceleration problem revisited

    DEFF Research Database (Denmark)

    Pécseli, H.L.; Trulsen, J.

    1991-01-01

    Phase-space diffusion of test particles in turbulent plasmas is studied by an approach based on a conditional statistical analysis of fluctuating electrostatic fields. Analytical relations between relevant conditional averages and higher-order correlations, , and triple...

  11. Potential application of X-ray communication through a plasma sheath encountered during spacecraft reentry into earth's atmosphere

    Science.gov (United States)

    Li, Huan; Tang, Xiaobin; Hang, Shuang; Liu, Yunpeng; Chen, Da

    2017-03-01

    Rapid progress in exploiting X-ray science has fueled its potential application in communication networks as a carrier wave for transmitting information through a plasma sheath during spacecraft reentry into earth's atmosphere. In this study, we addressed the physical transmission process of X-rays in the reentry plasma sheath and near-earth space theoretically. The interactions between the X-rays and reentry plasma sheath were investigated through the theoretical Wentzel-Kramers-Brillouin method, and the Monte Carlo simulation was employed to explore the transmission properties of X-rays in the near-earth space. The simulation results indicated that X-ray transmission was not influenced by the reentry plasma sheath compared with regular RF signals, and adopting various X-ray energies according to different spacecraft reentry altitudes is imperative when using X-ray uplink communication especially in the near-earth space. Additionally, the performance of the X-ray communication system was evaluated by applying the additive white Gaussian noise, Rayleigh fading channel, and plasma sheath channel. The Doppler shift, as a result of spacecraft velocity changes, was also calculated through the Matlab Simulink simulation, and various plasma sheath environments have no significant influence on X-ray communication owing to its exceedingly high carrier frequency.

  12. Theoretical and experimental studies of space-related plasma wave propagation and resonance phenomena

    Science.gov (United States)

    Crawford, F. W.

    1975-01-01

    A ten year summary was given of university research on the nature and characteristics of space related plasma resonance phenomena, whistler propagation in laboratory plasmas, and theoretical and experimental studies of plasma wave propagation. Data are also given on long delayed echoes, low frequency instabilities, ionospheric heating, and backscatter, and pulse propagation. A list is included of all conference papers, publications, and reports resulting from the study.

  13. Enhancement of space plasma images by complex wavelets

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Vitor Moura; Domingues, Margarete Oliveira; Mendes, Odim, E-mail: vitor.souza@inpe.br [Instituto Nacional de Pesquisas Espaciais (INPE), Sao Jose dos Campos, SP (Brazil); Pagamisse, Aylton [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Presidente Prudente, SP (Brazil). Fav. de Ciencias e Tecnologia; Stenborg, Guilhermo Adrian [College of Science, George Mason University, Fairfax, VA (United States)

    2015-10-15

    The Sun is a natural laboratory for plasma processes. A myriad of instruments aboard satellites and on ground record(ed) the plasma emission in different ranges of the electromagnetic spectrum to help understand such processes. In particular, in the outer part of the solar atmosphere, the solar corona, we can observe a multitude of electrodynamical phenomena. There, the faint corona emission and the associated dynamic plasma structures (e.g., coronal mass ejections - CMEs) recorded in white light images can be used as basis for some insight of this physical scenario. In order to characterize the dynamics and morphology of such structures in a better way, it seems crucial that some features of those images should be enhanced. To deal with this need, a new approach using a complex wavelet transform methodology was developed. With the proposed methodology, we can highlight the plasma ejections improving the identification of those structures. (author)

  14. Gas plasma sterilization--application of space-age technology.

    Science.gov (United States)

    Crow, S; Smith, J H

    1995-08-01

    Gas plasma sterilization is new to the healthcare field. The first such sterilizer has been manufactured by Advanced Sterilization Products (J&J, Irvine, CA). The system uses hydrogen peroxide as the substrate gas and radio frequency emissions to generate plasma. This system is a low-temperature, quick-acting process with no toxic residues. It appears that this sterilizer system holds promise in the healthcare field and could help to reduce the use of ethylene oxide.

  15. Plasma potential of a moving ionization zone in DC magnetron sputtering

    Science.gov (United States)

    Panjan, Matjaž; Anders, André

    2017-02-01

    Using movable emissive and floating probes, we determined the plasma and floating potentials of an ionization zone (spoke) in a direct current magnetron sputtering discharge. Measurements were recorded in a space and time resolved manner, which allowed us to make a three-dimensional representation of the plasma potential. From this information we could derive the related electric field, space charge, and the related spatial distribution of electron heating. The data reveal the existence of strong electric fields parallel and perpendicular to the target surface. The largest E-fields result from a double layer structure at the leading edge of the ionization zone. We suggest that the double layer plays a crucial role in the energization of electrons since electrons can gain several 10 eV of energy when crossing the double layer. We find sustained coupling between the potential structure, electron heating, and excitation and ionization processes as electrons drift over the magnetron target. The brightest region of an ionization zone is present right after the potential jump, where drifting electrons arrive and where most local electron heating occurs. The ionization zone intensity decays as electrons continue to drift in the Ez × B direction, losing energy by inelastic collisions; electrons become energized again as they cross the potential jump. This results in the elongated, arrowhead-like shape of the ionization zone. The ionization zone moves in the -Ez × B direction from which the to-be-heated electrons arrive and into which the heating region expands; the zone motion is dictated by the force of the local electric field on the ions at the leading edge of the ionization zone. We hypothesize that electron heating caused by the potential jump and physical processes associated with the double layer also apply to magnetrons at higher discharge power, including high power impulse magnetron sputtering.

  16. Space Nutrition: Effects on Bone and Potential Nutrition Countermeasures

    Science.gov (United States)

    Smith, Scott M.

    2008-01-01

    Optimal nutrition will be critical for crew members who embark on space exploration missions. Nutritional assessment provides an opportunity to ensure that crewmembers begin their missions in optimal nutritional status, to document changes during a mission and , if necessary, to provide intervention to maintain that status throughout the mission, and to assesses changes after landing in order to facilitate the return to their normal status as soon as possible after landing. We report here the findings from our nutritional assessment of the US astronauts who participated in the first eight International Space Station (ISS) missions. Bone loss during space flight remains one of the most critical challenges to astronaut health on space exploration missions. An increase in bone resorption of ISS crew members after flight was indicated by several markers. Vitamin D status also remains a challenge for long-duration space travelers, who lack ultraviolet light exposure in the shielded craft. Many nutrients affect bone, including calcium, protein, fatty acids, sodium, and others. Data supporting their potential as countermeasures for space flight, as published in many papers, will be reviewed in this presentation. Defining nutrient requirements, and being able to provide and maintain those nutrients on exploration missions, will be critical for maintaining crew member health. Please note, this abstract is not required for the meeting. A presentation on the topics described above will be given. This abstract is for travel documentation only.

  17. Space and Astrophysical Plasmas : Sun–Earth connection: Boundary layer waves and auroras

    Indian Academy of Sciences (India)

    G S Lakhina; B T Tsurutani; J K Arballo; C Galvan

    2000-11-01

    Boundary layers are the sites where energy and momentum are exchanged between two distinct plasmas. Boundary layers occurring in space plasmas can support a wide spectrum of plasma waves spanning a frequency range of a few mHz to 100 kHz and beyond. The main characteristics of the broadband plasma waves (with frequencies > 1 Hz) observed in the magnetopause, polar cap, and plasma sheet boundary layers are described. The rapid pitch angle scattering of energetic particles via cyclotron resonant interactions with the waves can provide sufficient precipitated energy flux to the ionosphere to create the diffused auroral oval. The broadband plasma waves may also play an important role in the processes of local heating/acceleration of the boundary layer plasma.

  18. Consistency of scalar potentials from quantum de Sitter space

    Science.gov (United States)

    Espinosa, José R.; Fortin, Jean-François; Trépanier, Maxime

    2016-06-01

    Consistency of the unconventional view of de Sitter space as a quantum theory of gravity with a finite number of degrees of freedom requires that Coleman-De Luccia tunneling rates to vacua with negative cosmological constant should be interpreted as recurrences to low-entropy states. This demand translates into two constraints, or consistency conditions, on the scalar potential that are generically as follows: (1) the distance in field space between the de Sitter vacuum and any other vacuum with negative cosmological constant must be of the order of the reduced Planck mass or larger and (2) the fourth root of the vacuum energy density of the de Sitter vacuum must be smaller than the fourth root of the typical scale of the scalar potential. These consistency conditions shed a different light on both outstanding hierarchy problems of the standard model of particle physics: the scale of electroweak symmetry breaking and the scale of the cosmological constant. Beyond the unconventional interpretation of quantum de Sitter space, we complete the analytic understanding of the thin-wall approximation of Coleman-De Luccia tunneling, extend its numerical analysis to generic potentials and discuss the role of gravity in stabilizing the standard model potential.

  19. Effect of space flights on plasma hormone levels in man and in experimental animal

    Science.gov (United States)

    Macho, L.; Kvetňanský, R.; Vigaš, M.; Németh, S.; Popova, I.; Tigranian, R. A.; Noskov, V. B.; Serova, L.; Grigoriev, I. A.

    An important increase of plasma hormone levels like insulin, TSH and aldosterone was observed in human subjects after space flights, however in the changes of plasma content of ACTH, cortisol, adrenaline and noradrenaline the individual variations were observed in relation to number and duration of space flight. For evaluation of the effects of these changes in plasma hormone levels on metabolic processes also the experiments with small animals subjected to space flights on a board of biosatellite of Cosmos series were running. An elevation of plasma levels of corticosterone, adrenaline, noradrenaline and insulin was found in rats after the space flights of duration from 7 to 20 days. It was demonstrated, that the increase of corticosterone in plasma is followed by the activation of enzymes involved in the aminoacid metabolism in rat liver (tyrosine aminotransferase, tryptophanpyrolase, alanine aminotransferase and aspartate aminotransferase). After a short recovery period (2 to 6 days) the plasma corticosterone concentration and also the activity of liver enzymes returned to control levels. The exposition of animals to stress stimuli during this recovery period showed higher response of corticosterone levels in flight rats as compared to intact controls. The increase of plasma catecholamine levels was not followed by elevation of lipolysis in adipose tissue. This is due to lower response of adipose tissue to catecholamine because a decrease of the stimulation of lipolysis by noradrenaline was observed in animals after space flight. The increase of insulin was not followed by adequate decrease of glucose concentration suggesting a disturbances in glucose utilization similarly as in cosmonauts after a long-term space flight. These results showed that changes in plasma hormone levels, observed after space flight, affected the regulation of metabolic processes in tissues.

  20. Electrostatic Structures in Space Plasmas: Stability of Two-dimensional Magnetic Bernstein-Greene-Kruskal Modes

    CERN Document Server

    Ng, C S; Yasin, E

    2011-01-01

    Electrostatic structures have been observed in many regions of space plasmas, including the solar wind, the magnetosphere, the auroral acceleration region, and in association with shocks, turbulence, and magnetic reconnection. Due to potentially large amplitude of electric fields within these structures, their effects on particle heating, scattering, or acceleration can be important. One possible theoretical description of some of these structures is the concept of Bernstein-Greene-Kruskal (BGK) modes, which are exact nonlinear solutions of the Vlasov-Poisson system of equations in collisionless kinetic theory. BGK modes have been studied extensively for many decades, predominately in one dimension (1D), although there have been observations showing that some of these structures have clear 3D features. While there have been approximate solutions of higher dimensional BGK modes, an exact 3D BGK mode solution in a finite magnetic field has not been found yet. Recently we have constructed exact solutions of 2D B...

  1. The magnetized dusty plasma discharge negative and positive space charge modes

    CERN Document Server

    Cramer, N F; Cramer, Neil F.; Vladimirov, Sergey

    2004-01-01

    The structure of a discharge across a magnetic field in a dusty plasma is analysed. The dust macroparticles are negatively charged, but are unmagnetized because of their high mass. The electrons are highly magnetized, and the ions have intermediate magnetization. This results in different transport rates of the different species across the magnetic field. Depending on the size of the magnetic field, and the relative charge on the different species, the dust grains can be the dominant current carrier. The space charge clouds near the electrodes will then be determined by the relative mobility of the different species. The discharge can operate in one of two modes, a positive space charge (PSC) mode, characterized by a strong cathode fall, and a negative space charge (NSC) mode, characterized by a broad anode fall. Features unique to the dust particles can also play a role in the structure of the discharge, such as the variable equilibrium charge on the grains, dependent on the local potential and species tempe...

  2. Negative-permittivity plasma generation in negative-permeability space with high-energy metamaterials

    Science.gov (United States)

    Sakai, Osamu; Nakamura, Yoshihiro; Iwai, Akinori; Iio, Satoshi

    2016-10-01

    Plasma generation by electromagnetic waves in negative-permeability space is analyzed using experimental results and theoretical models. Installation of negative-permeability metamaterials triggers drastic changes to the propagation of electromagnetic waves. Unlike usual cases in which permeability is  +1, negative permeability induces evanescent modes in a space without plasma. However, if permittivity becomes negative due to high-electron-density or overdense plasma, electromagnetic waves can propagate because negative-refractive-index states emerge. In this study, reviewing our previous experimental data, we study the underlying physical processes in plasma generation in terms of wave propagation and parameters of wave media. We confirm nonlinear (transition) processes in the phase of density evolution up to the negative permittivity state and negative-refractive-index states in the quasi-steady phase. We also note that such energetic metamaterials are built up when we use plasma, unlike conventional metamaterials composed of solid-state materials.

  3. Cross-scale energy transport in space plasmas

    Science.gov (United States)

    Moore, T. W.; Nykyri, K.; Dimmock, A. P.

    2016-12-01

    The solar wind is a supersonic magnetized plasma streaming far into the heliosphere. Although cooling as it flows, it is rapidly heated upon encountering planetary obstacles. At Earth, this interaction forms the magnetosphere and its sub-regions. The present paper focuses on particle heating across the boundary separating the shocked solar wind and magnetospheric plasma, which is driven by mechanisms operating on fluid, ion and electron scales. The cross-scale energy transport between these scales is a compelling and fundamental problem of plasma physics. Here, we present evidence of the energy transport between fluid and ion scales: free energy is provided in terms of a velocity shear generating fluid-scale Kelvin-Helmholtz instability. We show the unambiguous observation of an ion-scale magnetosonic wave packet, inside a Kelvin-Helmholtz vortex, with sufficient energy to account for observed ion heating. The present finding has universal consequences in understanding cross-scale energy transport, applicable to environments experiencing velocity shears during comparable plasma regimes.

  4. Magneto-Hydro-Dynamic Waves In The Collisionless Space Plasma

    Science.gov (United States)

    Dzhalilov, N. S.; Kuznetsov, V. D.; Staude, J.

    2007-12-01

    The instability of magneto-hydro-dynamic (MHD) waves in an anisotropic, collisionless, rarefied hot plasma is studied. Anisotropy properties of such a plasma are caused by a strong magnetic field, when the thermal gas pressures across and along the field become unequal. Moreover, there appears an anisotropy of the thermal fluxes. The study of the anisotropy features of the plasma are motivated by observed solar coronal data. The 16 moments equations derived from the Boltzmann-Vlasov kinetic equation are used. These equations strongly differ from the usual isotropic MHD case. For linear disturbances the wave equations in homogenous anisotropic plasma are deduced. The general dispersion relation for the incompressible wave modes is derived, solved and analyzed. It is shown that a wide wave spectrum with stable and unstable behavior is possible, in contrast to the usual isotropic MHD case. The dependence of the instability on magnetic field, pressure anisotropy, and heat fluxes is investigated. The general instability condition is obtained. The results can be applied to the theory of solar and stellar coronal heating, to wind models and in other modeling, where the collisionless approximation is valid.

  5. Space Plasma Studies by In-Situ and Remote Measurements

    Science.gov (United States)

    2007-11-02

    Awarded by Lenin Prize (highest in USSR). 1962 Plasma experiments aboard KOSMOS 2, evidence of the lack of charged particles thermodynamic equilibrium...ionosphere of Venus. 1970- 1979 Ionospheric experiments aboard COSMOS 378, INTERCOSMOS 8,10,12,14,18,19 and KOSMOS 900. 1970- 1981 Series of in

  6. Plasma YKL-40: a potential new cancer biomarker?

    DEFF Research Database (Denmark)

    Johansen, Julia S; Schultz, Nicolai A; Jensen, Benny V

    2009-01-01

    tissue remodeling. Plasma levels of YKL-40 are elevated in a subgroup of patients with primary or advanced cancer compared with age-matched healthy subjects, but also in patients with many different diseases characterized by inflammation. Elevated plasma YKL-40 levels are an independent prognostic...... by inflammation. Large prospective, longitudinal clinical cancer studies are needed to determine if plasma YKL-40 is a new cancer biomarker, or is mainly a biomarker of inflammation....

  7. Phase space structures in gyrokinetic simulations of fusion plasma turbulence

    Science.gov (United States)

    Ghendrih, Philippe; Norscini, Claudia; Cartier-Michaud, Thomas; Dif-Pradalier, Guilhem; Abiteboul, Jérémie; Dong, Yue; Garbet, Xavier; Gürcan, Ozgür; Hennequin, Pascale; Grandgirard, Virginie; Latu, Guillaume; Morel, Pierre; Sarazin, Yanick; Storelli, Alexandre; Vermare, Laure

    2014-10-01

    Gyrokinetic simulations of fusion plasmas give extensive information in 5D on turbulence and transport. This paper highlights a few of these challenging physics in global, flux driven simulations using experimental inputs from Tore Supra shot TS45511. The electrostatic gyrokinetic code GYSELA is used for these simulations. The 3D structure of avalanches indicates that these structures propagate radially at localised toroidal angles and then expand along the field line at sound speed to form the filaments. Analysing the poloidal mode structure of the potential fluctuations (at a given toroidal location), one finds that the low modes m = 0 and m = 1 exhibit a global structure; the magnitude of the m = 0 mode is much larger than that of the m = 1 mode. The shear layers of the corrugation structures are thus found to be dominated by the m = 0 contribution, that are comparable to that of the zonal flows. This global mode seems to localise the m = 2 mode but has little effect on the localisation of the higher mode numbers. However when analysing the pulsation of the latter modes one finds that all modes exhibit a similar phase velocity, comparable to the local zonal flow velocity. The consequent dispersion like relation between the modes pulsation and the mode numbers provides a means to measure the zonal flow. Temperature fluctuations and the turbulent heat flux are localised between the corrugation structures. Temperature fluctuations are found to exhibit two scales, small fluctuations that are localised by the corrugation shear layers, and appear to bounce back and forth radially, and large fluctuations, also readily observed on the flux, which are associated to the disruption of the corrugations. The radial ballistic velocity of both avalanche events if of the order of 0.5ρ∗c0 where ρ∗ = ρ0/a, a being the tokamak minor radius and ρ0 being the characteristic Larmor radius, ρ0 = c0/Ω0. c0 is the reference ion thermal velocity and Ω0 = qiB0/mi the reference

  8. Space and Astrophysical Plasmas : High energy universe – Satellite missions

    Indian Academy of Sciences (India)

    Vinod Krishan

    2000-11-01

    A variety of satellite missions to observe the high energy universe are currently operating and some more with more versatility and capability are on the anvil. In this paper, after giving a brief introduction to the constituents of the high energy universe and the related plasma physical problems, general as well as specific features of the current and future x-ray and gamma-ray satellite missions are described.

  9. Magnetic null points in kinetic simulations of space plasmas

    OpenAIRE

    Olshevsky, Vyacheslav; Deca, Jan; Divin, Andrey; Peng, Ivy Bo; Markidis, Stefano; Innocenti, Maria Elena; Cazzola, Emanuele; Lapenta, Giovanni

    2015-01-01

    We present a systematic attempt to study magnetic null points and the associated magnetic energy conversion in kinetic Particle-in-Cell simulations of various plasma configurations. We address three-dimensional simulations performed with the semi-implicit kinetic electromagnetic code iPic3D in different setups: variations of a Harris current sheet, dipolar and quadrupolar magnetospheres interacting with the solar wind; and a relaxing turbulent configuration with multiple null points. Spiral n...

  10. Tokamak Plasmas : Observation of floating potential asymmetry in the edge plasma of the SINP tokamak

    Indian Academy of Sciences (India)

    Krishnendu Bhattacharyya; N R Ray

    2000-11-01

    Edge plasma properties in a tokamak is an interesting subject of study from the view point of confinement and stability of tokamak plasma. The edge plasma of SINP-tokamak has been investigated using specially designed Langmuir probes. We have observed a poloidal asymmetry of floating potentials, particularly the top-bottom floating potential differences are quite noticeable, which in turn produces a vertical electric field (v). This v remains throughout the discharge but changes its direction at certain point of time which seems to depend on applied vertical magnetic field v).

  11. Using a CCD for the direct detection of electrons in a low energy space plasma spectrometer

    Science.gov (United States)

    Bedington, R.; Kataria, D.; Walton, D.

    2012-01-01

    An E2V CCD64 back-illuminated, ion-implanted CCD (charge-coupled device) has been used as a direct electron imaging detector with CATS (Conceptual And Tiny Spectrometer), a highly miniaturised prototype plasma analyser head. This is in place of an MCP (microchannel plate) with a position sensing anode which would more conventionally be used as a detector in traditional low energy space plasma analyser instruments. The small size of CATS however makes it well matched to the size of the CCD, and the ion implants reduce the depth of the CCD backside electron potential well making it more sensitive to lower energy electrons than standard untreated silicon. Despite ionisation damage from prolonged exposure to excessively energetic electrons, the CCD has been able to detect electrons with energies above 500eV, at temperatures around room temperature. Using both a long integration 'current measuring' mode and a short integration `electron counting' mode it has been used to image the low energy electrons exiting the analyser, enhancing our understanding of the CATS electrostatic optics. The CCD has been selected as the detector for use with CATS for an instrument on a low-altitude student sounding rocket flight. Although it cannot detect the lowest energy electrons that an MCP can detect, and it is more sensitive to stray light, the low voltages required, the lack of vacuum requirements and its novelty and availability made it the most attractive candidate detector.

  12. Effect of Ambipolar Potential on the Propulsive Performance of the GDM Plasma Thruster Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Gasdynamic Mirror (GDM) thruster is an electric propulsion device, without electrodes, that will magnetically confine a plasma with such density and temperature...

  13. A micro-scale plasma spectrometer for space and plasma edge applications (invited)

    Energy Technology Data Exchange (ETDEWEB)

    Scime, E. E., E-mail: escime@wvu.edu; Keesee, A. M.; Elliott, D. [Department of Physics, West Virginia University, Morgantown, West Virginia 26506-6315 (United States); Dugas, M.; Ellison, S.; Tersteeg, J.; Wagner, G. [Advanced Research Corporation, White Bear Lake, Minnesota 55110 (United States); Barrie, A.; Rager, A. [NASA Goddard Space Flight Center, Greenbelt, Maryland 20771 (United States)

    2016-11-15

    A plasma spectrometer design based on advances in lithography and microchip stacking technologies is described. A series of curved plate energy analyzers, with an integrated collimator, is etched into a silicon wafer. Tests of spectrometer elements, the energy analyzer and collimator, were performed with a 5 keV electron beam. The measured collimator transmission and energy selectivity were in good agreement with design targets. A single wafer element could be used as a plasma processing or fusion first wall diagnostic.

  14. A micro-scale plasma spectrometer for space and plasma edge applications (invited)

    Science.gov (United States)

    Scime, E. E.; Keesee, A. M.; Dugas, M.; Ellison, S.; Tersteeg, J.; Wagner, G.; Barrie, A.; Rager, A.; Elliott, D.

    2016-11-01

    A plasma spectrometer design based on advances in lithography and microchip stacking technologies is described. A series of curved plate energy analyzers, with an integrated collimator, is etched into a silicon wafer. Tests of spectrometer elements, the energy analyzer and collimator, were performed with a 5 keV electron beam. The measured collimator transmission and energy selectivity were in good agreement with design targets. A single wafer element could be used as a plasma processing or fusion first wall diagnostic.

  15. Physics of Phase Space Matching for Staging Plasma and Traditional Accelerator Components Using Longitudinally Tailored Plasma Profiles.

    Science.gov (United States)

    Xu, X L; Hua, J F; Wu, Y P; Zhang, C J; Li, F; Wan, Y; Pai, C-H; Lu, W; An, W; Yu, P; Hogan, M J; Joshi, C; Mori, W B

    2016-03-25

    Phase space matching between two plasma-based accelerator (PBA) stages and between a PBA and a traditional accelerator component is a critical issue for emittance preservation. The drastic differences of the transverse focusing strengths as the beam propagates between stages and components may lead to a catastrophic emittance growth even when there is a small energy spread. We propose using the linear focusing forces from nonlinear wakes in longitudinally tailored plasma density profiles to control phase space matching between sections with negligible emittance growth. Several profiles are considered and theoretical analysis and particle-in-cell simulations show how these structures may work in four different scenarios. Good agreement between theory and simulation is obtained, and it is found that the adiabatic approximation misses important physics even for long profiles.

  16. Surface Charging Controlling of the Chinese Space Station with Hollow Cathode Plasma Contactor

    Science.gov (United States)

    Jiang, Kai; Wang, Xianrong; Qin, Xiaogang; Yang, Shengsheng; Yang, Wei; Zhao, Chengxuan; Chen, Yifeng; Shi, Liang; Tang, Daotan; Xie, Kan

    2016-07-01

    A highly charged manned spacecraft threatens the life of an astronaut and extravehicular activity, which can be effectively reduced by controlling the spacecraft surface charging. In this article, the controlling of surface charging on Chinese Space Station (CSS) is investigated, and a method to reduce the negative potential to the CSS is the emission electron with a hollow cathode plasma contactor. The analysis is obtained that the high voltage (HV) solar array of the CSS collecting electron current can reach 4.5 A, which can be eliminated by emitting an adequate electron current on the CSS. The theoretical analysis and experimental results are addressed, when the minimum xenon flow rate of the hollow cathode is 4.0 sccm, the emission electron current can neutralize the collected electron current, which ensures that the potential of the CSS can be controlled in a range of less than 21 V, satisfied with safety voltage. The results can provide a significant reference value to define a flow rate to the potential controlling programme for CSS.

  17. The Potential for Ambient Plasma Wave Propulsion Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This concept addresses the fact that space exploration is costly, primarily due to our current need to bring everything with us from the Earth’s surface....

  18. Observed Coupling Between the International Space Station PCU Plasma and a FPMU Langmuir Probe Facilitated by the Geomagnetic Field

    Science.gov (United States)

    Hartman, William; Koontz, Steven L.

    2010-01-01

    Electrical charging of the International Space Station (ISS) is a matter of serious concern resulting from the possibility of vehicle arcing and electrical shock hazard to crew during extravehicular activity (EVA). A Plasma Contactor Unit (PCU) was developed and integrated into ISS in order to control the ISS floating potential, thereby, minimize vehicle charging and associated hazards. One of the principle factors affecting ISS electrical charging is the ionosphere plasma state (i.e., electron temperature and density). To support ISS electrical charging studies a Floating Potential Monitoring Unit (FPMU) is also integrated into ISS in order to measure the ionosphere properties using Langmuir probes (LP). The FPMU was located on the Starboard side of ISS. The PCU is located near the center of ISS with its plasma exhaust pointed to port. From its integration on ISS in 2006 through November of 2009, the FPMU data exhibited nominal characteristics during PCU operation. On November 21, 2009 the FPMU was relocated from the Starboard location to a new Port location. After relocation significant enhanced noise was observed in both the LP current-voltage sweeps and the derived electron temperature data. The enhanced noise only occurred when the PCU was in discharge and at unique and repeatable locations of the ISS orbit. The cause of this enhanced noise was investigated. It was found that there is coupling occurring between the PCU plasma and the FPMU LP. In this paper we shall 1) present the on-orbit data and the presence of enhanced noise, 2) demonstrate that the coupling of the PCU plasma and the FPMU measurements is geomagnetically organized, 3) show that coupling of the PCU plasma and the FPMU is primarily due to and driven by particle-wave interaction and 4) show that the ionosphere conditions are adequate for Alfven waves to be generated by the PCU plasma.

  19. Cross-Scale: Multi-Scale Coupling in Space Plasma, Assessment Study Report

    CERN Document Server

    Schwartz, Steve; Fujimoto, Masaki; Hellinger, Petr; Kessel, Mona; Le, Guan; Liu, William; Louarn, Philippe; Mann, Ian; Nakamura, Rumi; Owen, Chris; Pinçon, Jean-Louis; Sorriso-Valvo, Luca; Vaivads, Andris; Wimmer-Schweingruber, Robert F

    2009-01-01

    Driven by the support and interest of the international space plasma community to examine simultaneous physical plasma scales and their interactions, the Cross-Scale Mission concept was submitted and accepted as an ESA Cosmic Vision M-class candidate mission. This report presents an overview of the assessment study phase of the 7 ESA spacecraft Cross-Scale mission. Where appropriate, discussion of the benefit of international collaboration with the SCOPE mission, as well as other interested parties, is included.

  20. Dusty Plasma Research under Microgravity: from the Orbital Station ``Mir'' to the International Space Station

    Science.gov (United States)

    Fortov, Vladimir

    Dusty, or complex plasmas are composed of a weakly ionized gas and charged microparticles. Dust and dusty plasmas are ubiquitous in space -- they are present in planetary rings, cometary tails, interplanetary and interstellar clouds, the mesosphere, thunderclouds, they are found in the vicinity of artificial satellites and space stations, etc. Dusty plasmas formed by micronsize particles are actively investigated in many laboratories. This research has many interesting applications like nanomaterial synthesis, nanoparticle handling or particle waste removal just to mention a few. But, the most interesting application of dusty plasmas is the use as model systems for fundamental physics. It allows investigation on the most fundamental -- the kinetic level and provides insights into physics of solids and liquids with a precision not achievable in natural systems. Experiments performed on Earth are always altered or even hindered by gravity. Microgravity conditions are necessary to make investigations of large homogeneous 3-dimensional dusty plasma systems. Here we present the survey of results of the dusty plasma physics investigations under microgravity conditions with the help of experimental installations ``Plasma Crystal-1'' (PK-1) and ``PK-2'' used on the Orbital Station ``Mir'', and the unique experimental installations ``PK-3'' and ``PK-3 Plus'' used on the International Space Station. The use of these installations has given a possibility to obtain new knowledge on the dusty plasma properties. The phase transition from the isotropic liquid dusty plasma system to the so-called electrorheological plasma has been performed. The transition is the isotropic one and is fully reversible. The other interesting phenomenon is an interpenetration of two clouds of microparticles of different sizes. When a velocity of the penetrating particles is rather high the lane formation has been observed. This phenomenon is the non-equilibrium transition, depends upon peculiarities

  1. Charging of small grains in a space plasma: Application to Jovian stream particles

    CERN Document Server

    Dzhanoev, A R; Liu, X; Spahn, F

    2016-01-01

    Most theoretical investigations of dust charging processes in space have treated the current balance condition as independent of grain size. However, for small grains, as they are often observed in space environments, a dependence on grain size is expected due to secondary electron emission (SEE). Here, by the term "small" we mean a particle size comparable to the typical penetration depth for given primary electron energy. The results are relevant for the dynamics of small, charged dust particles emitted by the volcanic moon Io, which form the Jovian dust streams. We revise the theory of charging of small (sub-micron sized) micrometeoroids to take into account a high production of secondary electrons for small grains immersed in an isotropic flux of electrons. We apply our model to obtain an improved estimate for the charge of the dust streams leaving the Jovian system, detected by several spacecraft. For the Jupiter plasma environment we derive the surface potential of grains composed of NaCl (believed to b...

  2. Space plasma physics at the Applied Physics Laboratory over the past half-century

    Science.gov (United States)

    Potemra, Thomas A.

    1992-01-01

    An overview is given of space-plasma experiments conducted at the Applied Physics Laboratory (APL) at Johns Hopkins University including observational campaigns and the instrumentation developed. Specific space-plasma experiments discussed include the study of the radiation environment in the Van Allen radiation belt with solid-state proton detectors. Also described are the 5E-1 satellites which acquired particle and magnetic-field data from earth orbit. The Triad satellite and its magnetometer system were developed for high-resolution studies of the earth's magnetic field, and APL contributions to NASA's Interplanetary Monitoring Platforms are listed. The review mentions the International Ultraviolet Explorer, the Atmosphere Explorer mission, and the Active Magnetic Particle Tracer Explorers mission. Other recent programs reviewed include a high-latitude satellite, contributions to the Voyager mission, and radar studies of space plasmas.

  3. Misestimation of temperature when applying Maxwellian distributions to space plasmas described by kappa distributions

    Science.gov (United States)

    Nicolaou, Georgios; Livadiotis, George

    2016-11-01

    This paper presents the misestimation of temperature when observations from a kappa distributed plasma are analyzed as a Maxwellian. One common method to calculate the space plasma parameters is by fitting the observed distributions using known analytical forms. More often, the distribution function is included in a forward model of the instrument's response, which is used to reproduce the observed energy spectrograms for a given set of plasma parameters. In both cases, the modeled plasma distribution fits the measurements to estimate the plasma parameters. The distribution function is often considered to be Maxwellian even though in many cases the plasma is better described by a kappa distribution. In this work we show that if the plasma is described by a kappa distribution, the derived temperature assuming Maxwell distribution can be significantly off. More specifically, we derive the plasma temperature by fitting a Maxwell distribution to pseudo-data produced by a kappa distribution, and then examine the difference of the derived temperature as a function of the kappa index. We further consider the concept of using a forward model of a typical plasma instrument to fit its observations. We find that the relative error of the derived temperature is highly depended on the kappa index and occasionally on the instrument's field of view and response.

  4. Space-dependent characterization of laser-induced plasma plume during fiber laser welding

    Science.gov (United States)

    Xiao, Xianfeng; Song, Lijun; Xiao, Wenjia; Liu, Xingbo

    2016-12-01

    The role of a plasma plume in high power fiber laser welding is of considerable interest due to its influence on the energy transfer mechanism. In this study, the space-dependent plasma characteristics including spectrum intensity, plasma temperature and electron density were investigated using optical emission spectroscopy technique. The plasma temperature was calculated using the Boltzmann plot of atomic iron lines, whereas the electron density was determined from the Stark broadening of the Fe I line at 381.584 nm. Quantitative analysis of plasma characteristics with respect to the laser radiation was performed. The results show that the plasma radiation increases as the laser power increases during the partial penetration mode, and then decreases sharply after the initiation of full penetration. Both the plasma temperature and electron density increase with the increase of laser power until they reach steady state values after full penetration. Moreover, the hottest core of the plasma shifts toward the surface of the workpiece as the penetration depth increases, whereas the electron density is more evenly distributed above the surface of the workpiece. The results also indicate that the absorption and scattering of nanoparticles in the plasma plume is the main mechanism for laser power attenuation.

  5. Herz-type Sobolev and Bessel potential spaces and their applications

    Institute of Scientific and Technical Information of China (English)

    陆善镇; 杨大春

    1997-01-01

    The Herz-type Sobolev spaces are introduced and the Sobolev theorem is established. The Herz-type Bessel potential spaces and the relation between the Herz-type Sobolev spaces and Bessel potential spaces are discussed. As applications of these theories, some regularity results of nonlinear quantities appearing in the compensated compactness theory on Herz-type Hardy spaces are given.

  6. On the rogue waves propagation in non-Maxwellian complex space plasmas

    Science.gov (United States)

    El-Tantawy, S. A.; El-Awady, E. I.; Tribeche, M.

    2015-11-01

    The implications of the non-Maxwellian electron distributions (nonthermal/or suprathermal/or nonextensive distributions) are examined on the dust-ion acoustic (DIA) rogue/freak waves in a dusty warm plasma. Using a reductive perturbation technique, the basic set of fluid equations is reduced to a nonlinear Schrödinger equation. The latter is used to study the nonlinear evolution of modulationally unstable DIA wavepackets and to describe the rogue waves (RWs) propagation. Rogue waves are large-amplitude short-lived wave groups, routinely observed in space plasmas. The possible region for the rogue waves to exist is defined precisely for typical parameters of space plasmas. It is shown that the RWs strengthen for decreasing plasma nonthermality and increasing superthermality. For nonextensive electrons, the RWs amplitude exhibits a bit more complex behavior, depending on the entropic index q. Moreover, our numerical results reveal that the RWs exist with all values of the ion-to-electron temperature ratio σ for nonthermal and superthermal distributions and there is no limitation for the freak waves to propagate in both two distributions in the present plasma system. But, for nonextensive electron distribution, the bright- and dark-type waves can propagate in this case, which means that there is a limitation for the existence of freak waves. Our systematic investigation should be useful in understanding the properties of DIA solitary waves that may occur in non-Maxwellian space plasmas.

  7. On the rogue waves propagation in non-Maxwellian complex space plasmas

    Energy Technology Data Exchange (ETDEWEB)

    El-Tantawy, S. A., E-mail: samireltantawy@yahoo.com; El-Awady, E. I., E-mail: eielawady@hotmail.com [Department of Physics, Faculty of Science, Port Said University, Port Said 42521 (Egypt); Tribeche, M., E-mail: mouloudtribeche@yahoo.fr, E-mail: mtribeche@usthb.dz [Plasma Physics Group, Theoretical Physics Laboratory, Faculty of Physics, University of Bab-Ezzouar, USTHB, BP 32, El Alia, Algiers 16111 (Algeria)

    2015-11-15

    The implications of the non-Maxwellian electron distributions (nonthermal/or suprathermal/or nonextensive distributions) are examined on the dust-ion acoustic (DIA) rogue/freak waves in a dusty warm plasma. Using a reductive perturbation technique, the basic set of fluid equations is reduced to a nonlinear Schrödinger equation. The latter is used to study the nonlinear evolution of modulationally unstable DIA wavepackets and to describe the rogue waves (RWs) propagation. Rogue waves are large-amplitude short-lived wave groups, routinely observed in space plasmas. The possible region for the rogue waves to exist is defined precisely for typical parameters of space plasmas. It is shown that the RWs strengthen for decreasing plasma nonthermality and increasing superthermality. For nonextensive electrons, the RWs amplitude exhibits a bit more complex behavior, depending on the entropic index q. Moreover, our numerical results reveal that the RWs exist with all values of the ion-to-electron temperature ratio σ for nonthermal and superthermal distributions and there is no limitation for the freak waves to propagate in both two distributions in the present plasma system. But, for nonextensive electron distribution, the bright- and dark-type waves can propagate in this case, which means that there is a limitation for the existence of freak waves. Our systematic investigation should be useful in understanding the properties of DIA solitary waves that may occur in non-Maxwellian space plasmas.

  8. Some consequences of intense electromagnetic wave injection into space plasmas

    Science.gov (United States)

    Burke, William J.; Villalon, Elena; Rothwell, Paul L.; Silevitch, Michael

    1986-10-01

    The future possibility of actively testing the current understanding of how energetic particles may be accelerated in space or dumped from the radiation belts using intense electromagnetic energy from ground based antennas is discussed. The ground source of radiation is merely a convenience. A space station source for radiation that does not have to pass through the atmosphere and lower ionosphere, is an attractive alternative. The text is divided into two main sections addressing the possibilities of: (1) accelerating electrons to fill selected flux tubes above the Kennel-Petscheck limit for stably trapped fluxes, and (2) using an Alfven maser to cause rapid depletion of energetic protons or electrons from the radiation belts.

  9. The scientific potential of space-based gravitational wave detectors

    CERN Document Server

    Gair, Jonathan R

    2014-01-01

    The millihertz gravitational wave band can only be accessed with a space-based interferometer, but it is one of the richest in potential sources. Observations in this band have amazing scientific potential. The mergers between massive black holes with mass in the range 10 thousand to 10 million solar masses, which are expected to occur following the mergers of their host galaxies, produce strong millihertz gravitational radiation. Observations of these systems will trace the hierarchical assembly of structure in the Universe in a mass range that is very difficult to probe electromagnetically. Stellar mass compact objects falling into such black holes in the centres of galaxies generate detectable gravitational radiation for several years prior to the final plunge and merger with the central black hole. Measurements of these systems offer an unprecedented opportunity to probe the predictions of general relativity in the strong-field and dynamical regime. Millihertz gravitational waves are also generated by mil...

  10. Spaced-Resolved Electron Density of Aluminum Plasma Produced by Frequency-Tripled Laser

    Institute of Scientific and Technical Information of China (English)

    Yang Boqian; Han Shensheng; Zhang Jiyan; Zheng Zhijian; Yang Guohong; Yang Jiaming; Li Jun; Wang Yan

    2005-01-01

    By using the space-resolved spectrograph, the K-shell emission from laser-produced plasma was investigated. Electron density profiles along the normal direction of the target surface in aluminum laser-plasmas were obtained by two different diagnostic methods and compared with the profiles from the theoretical simulation of hydrodynamics code MULTI1D. The results corroborate the feasibility to obtain the electron density above the critical surface by the diagnostic method based on the Stark-broadened wings in the intermediately coupled plasmas.

  11. Magnetic reconnection rate in space plasmas: a fractal approach.

    Science.gov (United States)

    Materassi, Massimo; Consolini, Giuseppe

    2007-10-26

    Magnetic reconnection is generally discussed via a fluid description. Here, we evaluate the reconnection rate assuming a fractal topology of the reconnection region. The central idea is that the fluid hypothesis may be violated at the scales where reconnection takes place. The reconnection rate, expressed as the Alfvén Mach number of the plasma moving toward the diffusion region, is shown to depend on the fractal dimension and on the sizes of the reconnection or diffusion region. This mechanism is more efficient than prediction of the Sweet-Parker model and even Petschek's model for finite magnetic Reynolds number. A good agreement also with rates given by Hall MHD models is found. A discussion of the fractal assumption on the diffusion region in terms of current microstructures is proposed. The comparison with in-situ satellite observations suggests the reconnection region to be a filamentary domain.

  12. Nonextensive entropy approach to space plasma fluctuations and turbulence

    CERN Document Server

    Leubner, M P; Baumjohann, W

    2006-01-01

    Spatial intermittency in fully developed turbulence is an established feature of astrophysical plasma fluctuations and in particular apparent in the interplanetary medium by in situ observations. In this situation the classical Boltzmann-Gibbs extensive thermo-statistics, applicable when microscopic interactions and memory are short ranged, fails. Upon generalization of the entropy function to nonextensivity, accounting for long-range interactions and thus for correlations in the system, it is demonstrated that the corresponding probability distributions (PDFs) are members of a family of specific power-law distributions. In particular, the resulting theoretical bi-kappa functional reproduces accurately the observed global leptokurtic, non-Gaussian shape of the increment PDFs of characteristic solar wind variables on all scales. Gradual decoupling is obtained by enhancing the spatial separation scale corresponding to increasing kappa-values in case of slow solar wind conditions where a Gaussian is approached i...

  13. Space-time evolution of ejected plasma for the triggering of gas switch

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Shanhong, E-mail: liushanhong108098@163.com; Liu, Xuandong; Shen, Xi; Feng, Lei; Zhang, Qiaogen [State Key Laboratory of Electrical Insulation and Power Equipment, School of Electrical Engineering, Institute of High Voltage Technology, Xi' an Jiaotong University, Xi' an 710049 (China); Tie, Weihao [Xi' an Electrical Engineering Research Institute, Xi' an 710049 (China)

    2016-06-15

    Ejected plasma has been widely applied to the discharge process of gas spark switches as a trigger technology, and the development process of ejected plasma has a direct and important effect on the discharge characteristics of gas switches. In this paper, both the injection characteristics and space-time evolution of ejected plasma for the triggering of gas spark switch with different stored energies, pulse polarities, and pressures are studied. The discharge characteristics and breakdown process of a gas switch ignited by ejected plasma under different working coefficients are also discussed briefly. The results show that stored energy has significant influence on the characteristics of ejected plasma. With the increase of stored energy, the propulsion mode of ejected plasma in the axial direction transforms from “plasmoid” to “plasma flow,” and the distribution of the ejected plasma goes through “cloud,” “core-cloud,” and “branch” in sequence. The velocity of ejected plasma under negative pulse polarity is obviously higher than that under positive pulse polarity, especially at the very beginning time. The radial dimensions of ejected plasma under two kinds of pulse polarities follow the similar varying pattern over time, which increase first and then decrease, assuming an inverted “U”-shaped curve. With the increase of pressure, the velocity of ejected plasma significantly decreases and the “branch” channels droop earlier. Applying the ejected plasma to the triggering of a gas switch, the switch can be triggered reliably in a much wide working coefficient range of 10%–90%. With the increase of working coefficient, the breakdown process of the switch translates from slow working mode to fast working mode, and the delay time reduces from tens of μs to hundreds of ns.

  14. Space-time evolution of ejected plasma for the triggering of gas switch

    Science.gov (United States)

    Liu, Shanhong; Liu, Xuandong; Shen, Xi; Feng, Lei; Tie, Weihao; Zhang, Qiaogen

    2016-06-01

    Ejected plasma has been widely applied to the discharge process of gas spark switches as a trigger technology, and the development process of ejected plasma has a direct and important effect on the discharge characteristics of gas switches. In this paper, both the injection characteristics and space-time evolution of ejected plasma for the triggering of gas spark switch with different stored energies, pulse polarities, and pressures are studied. The discharge characteristics and breakdown process of a gas switch ignited by ejected plasma under different working coefficients are also discussed briefly. The results show that stored energy has significant influence on the characteristics of ejected plasma. With the increase of stored energy, the propulsion mode of ejected plasma in the axial direction transforms from "plasmoid" to "plasma flow," and the distribution of the ejected plasma goes through "cloud," "core-cloud," and "branch" in sequence. The velocity of ejected plasma under negative pulse polarity is obviously higher than that under positive pulse polarity, especially at the very beginning time. The radial dimensions of ejected plasma under two kinds of pulse polarities follow the similar varying pattern over time, which increase first and then decrease, assuming an inverted "U"-shaped curve. With the increase of pressure, the velocity of ejected plasma significantly decreases and the "branch" channels droop earlier. Applying the ejected plasma to the triggering of a gas switch, the switch can be triggered reliably in a much wide working coefficient range of 10%-90%. With the increase of working coefficient, the breakdown process of the switch translates from slow working mode to fast working mode, and the delay time reduces from tens of μs to hundreds of ns.

  15. The Potential of Small Space Telescopes for Exoplanet Observations

    Science.gov (United States)

    Serabyn, E.

    2010-01-01

    The imaging of faint exoplanets near bright stars requires the development of very high contrast detection techniques, including both precise wavefront control and deep starlight rejection. A system-level proof-of-principle experiment carried out at at the Palomar Observatory has recently demonstrated that exoplanets can be detected very near stars even with a fairly small (1.5 m diameter) telescope aperture, such as someday might be used by a first space-based exoplanet imaging mission. Using fine-scale wavefront correction across this small aperture, together with fine pointing and focus control, pre- and post-detection speckle reduction, and a vector vortex coronagraph, it has been possible to achieve extremely good starlight rejection within a small number of diffractions beams of the stellar position. This performance has recently allowed the imaging of the three HR8799 planets and the HD32297 disk, thus providing a first system-level validation of the steps needed to achieve high-contrast observations at very small angles. These results thus serve to highlight the potential of small space telescopes aiming at high-contrast exoplanet observations. Specifically, a small-angle coronagraph enables the use of smaller telescopes, thus potentially reducing mission cost significantly.

  16. Laser plasma simulations of the generation processes of Alfven and collisionless shock waves in space plasma

    Science.gov (United States)

    Prokopov, P. A.; Zakharov, Yu P.; Tishchenko, V. N.; Shaikhislamov, I. F.; Boyarintsev, E. L.; Melekhov, A. V.; Ponomarenko, A. G.; Posukh, V. G.; Terekhin, V. A.

    2016-11-01

    Generation of Alfven waves propagating along external magnetic field B0 and Collisionless Shock Waves propagating across B0 are studied in experiments with laser- produced plasma and magnetized background plasma. The collisionless interaction of interpenetrating plasma flows takes place through a so-called Magnetic Laminar Mechanism (MLM) or Larmor Coupling. At the edge of diamagnetic cavity LP-ions produce induction electric field Eφ which accelerates BP-ions while LP-ions rotate in opposite direction. The ions movement generates sheared azimuthal magnetic field Bφ which could launches torsional Alfven wave. In previous experiments at KI-1 large scale facility a generation of strong perturbations propagating across B0 with magnetosonic speed has been studied at a moderate value of interaction parameter δ∼0.3. In the present work we report on experiments at conditions of 5∼R2 and large Alfven-Mach number MA∼10 in which strong transverse perturbations traveling at a scale of ∼1 m in background plasma at a density of ∼3*1013 cm-3 is observed. At the same conditions but smaller MA ∼ 2 a generation, the structure and dynamic of Alfven wave with wavelength ∼0.5 m propagating along fields B0∼100÷500 G for a distance of ∼2.5 m is studied.

  17. On Floating Potential of Emissive Probes in a Partially-Magnetized Plasma

    Science.gov (United States)

    Raitses, Yevgeny; Kraus, Brian

    2016-10-01

    We compare measurements of plasma potential in a cross-field Penning discharge from two probes: swept biased Langmuir probe and floating emissive probe. The plasma potential was deduced from the first derivative of the Langmuir probe characteristic. In previous studies, the emissive and swept biased probes were placed at the channel exit of a Hall thruster (HT). Measurements showed that the emissive probe floats below the plasma potential, in agreement with conventional theories. However, recent measurements in the Penning discharge indicate a floating potential of a strongly-emitting hot probe above the plasma potential. In both probe applications, xenon plasmas have magnetized electrons and non-magnetized ions with similar plasma densities (1010 - 1011 cm-3) . Though their electron temperatures differ by an order of magnitude (Penning 5 eV, HT 50 eV), this difference cannot explain the difference in measurement values of the hot floating potential because both temperatures are much higher than the emitting wire. In this work, we investigate how the ion velocity and other plasma parameters affect this discrepancy between probe measurements of the plasma potential. This work was supported by DOE contract DE-AC02-09CH11466.

  18. Designing of a risk assessment architecture to analyze potential risks from space weather to space and ground based assets

    Science.gov (United States)

    Sattar, Erum

    2016-07-01

    Today's world is more vulnerable to space weather due to ever increased advance and costly space technology deployed in space and on ground. The space weather has a natural potential of posing harmful effects on space and ground based assets and on astronaut's life. This global challenge of space weather essentially demands global and regional preparedness to develop its situational awareness, analyzing risks and devise possible mitigation procedures. Considering risk mitigation architecture as inevitable for all scientific missions, this paper focuses to develop a risk assessment architecture for the space environment and to map its utility in identifying and analyzing potential risks to space and ground based assets from space weather in the South Asia region. Different risk assessment tools will be studied and would conclude in the most effective tool or strategy that may help to develop our capability in identifying, protecting and mitigating from the devastating effects of the space weather.

  19. Performance of a space-based wavelet compressor for plasma count data on the MMS Fast Plasma Investigation

    Science.gov (United States)

    Barrie, A. C.; Smith, S. E.; Dorelli, J. C.; Gershman, D. J.; Yeh, P.; Schiff, C.; Avanov, L. A.

    2017-01-01

    Data compression has been a staple of imaging instruments for years. Recently, plasma measurements have utilized compression with relatively low compression ratios. The Fast Plasma Investigation (FPI) on board the Magnetospheric Multiscale (MMS) mission generates data roughly 100 times faster than previous plasma instruments, requiring a higher compression ratio to fit within the telemetry allocation. This study investigates the performance of a space-based compression standard employing a Discrete Wavelet Transform and a Bit Plane Encoder (DWT/BPE) in compressing FPI plasma count data. Data from the first 6 months of FPI operation are analyzed to explore the error modes evident in the data and how to adapt to them. While approximately half of the Dual Electron Spectrometer (DES) maps had some level of loss, it was found that there is little effect on the plasma moments and that errors present in individual sky maps are typically minor. The majority of Dual Ion Spectrometer burst sky maps compressed in a lossless fashion, with no error introduced during compression. Because of induced compression error, the size limit for DES burst images has been increased for Phase 1B. Additionally, it was found that the floating point compression mode yielded better results when images have significant compression error, leading to floating point mode being used for the fast survey mode of operation for Phase 1B. Despite the suggested tweaks, it was found that wavelet-based compression, and a DWT/BPE algorithm in particular, is highly suitable to data compression for plasma measurement instruments and can be recommended for future missions.

  20. Plasmakristall-4: New complex (dusty) plasma laboratory on board the International Space Station.

    Science.gov (United States)

    Pustylnik, M Y; Fink, M A; Nosenko, V; Antonova, T; Hagl, T; Thomas, H M; Zobnin, A V; Lipaev, A M; Usachev, A D; Molotkov, V I; Petrov, O F; Fortov, V E; Rau, C; Deysenroth, C; Albrecht, S; Kretschmer, M; Thoma, M H; Morfill, G E; Seurig, R; Stettner, A; Alyamovskaya, V A; Orr, A; Kufner, E; Lavrenko, E G; Padalka, G I; Serova, E O; Samokutyayev, A M; Christoforetti, S

    2016-09-01

    New complex-plasma facility, Plasmakristall-4 (PK-4), has been recently commissioned on board the International Space Station. In complex plasmas, the subsystem of μm-sized microparticles immersed in low-pressure weakly ionized gas-discharge plasmas becomes strongly coupled due to the high (10(3)-10(4) e) electric charge on the microparticle surface. The microparticle subsystem of complex plasmas is available for the observation at the kinetic level, which makes complex plasmas appropriate for particle-resolved modeling of classical condensed matter phenomena. The main purpose of PK-4 is the investigation of flowing complex plasmas. To generate plasma, PK-4 makes use of a classical dc discharge in a glass tube, whose polarity can be switched with the frequency of the order of 100 Hz. This frequency is high enough not to be felt by the relatively heavy microparticles. The duty cycle of the polarity switching can be also varied allowing to vary the drift velocity of the microparticles and (when necessary) to trap them. The facility is equipped with two videocameras and illumination laser for the microparticle imaging, kaleidoscopic plasma glow observation system and minispectrometer for plasma diagnostics and various microparticle manipulation devices (e.g., powerful manipulation laser). Scientific experiments are programmed in the form of scripts written with the help of specially developed C scripting language libraries. PK-4 is mainly operated from the ground (control center CADMOS in Toulouse, France) with the support of the space station crew. Data recorded during the experiments are later on delivered to the ground on the removable hard disk drives and distributed to participating scientists for the detailed analysis.

  1. Plasmakristall-4: New complex (dusty) plasma laboratory on board the International Space Station

    Science.gov (United States)

    Pustylnik, M. Y.; Fink, M. A.; Nosenko, V.; Antonova, T.; Hagl, T.; Thomas, H. M.; Zobnin, A. V.; Lipaev, A. M.; Usachev, A. D.; Molotkov, V. I.; Petrov, O. F.; Fortov, V. E.; Rau, C.; Deysenroth, C.; Albrecht, S.; Kretschmer, M.; Thoma, M. H.; Morfill, G. E.; Seurig, R.; Stettner, A.; Alyamovskaya, V. A.; Orr, A.; Kufner, E.; Lavrenko, E. G.; Padalka, G. I.; Serova, E. O.; Samokutyayev, A. M.; Christoforetti, S.

    2016-09-01

    New complex-plasma facility, Plasmakristall-4 (PK-4), has been recently commissioned on board the International Space Station. In complex plasmas, the subsystem of μm-sized microparticles immersed in low-pressure weakly ionized gas-discharge plasmas becomes strongly coupled due to the high (103-104 e) electric charge on the microparticle surface. The microparticle subsystem of complex plasmas is available for the observation at the kinetic level, which makes complex plasmas appropriate for particle-resolved modeling of classical condensed matter phenomena. The main purpose of PK-4 is the investigation of flowing complex plasmas. To generate plasma, PK-4 makes use of a classical dc discharge in a glass tube, whose polarity can be switched with the frequency of the order of 100 Hz. This frequency is high enough not to be felt by the relatively heavy microparticles. The duty cycle of the polarity switching can be also varied allowing to vary the drift velocity of the microparticles and (when necessary) to trap them. The facility is equipped with two videocameras and illumination laser for the microparticle imaging, kaleidoscopic plasma glow observation system and minispectrometer for plasma diagnostics and various microparticle manipulation devices (e.g., powerful manipulation laser). Scientific experiments are programmed in the form of scripts written with the help of specially developed C scripting language libraries. PK-4 is mainly operated from the ground (control center CADMOS in Toulouse, France) with the support of the space station crew. Data recorded during the experiments are later on delivered to the ground on the removable hard disk drives and distributed to participating scientists for the detailed analysis.

  2. Transport formulas for multi-component plasmas within the effective potential theory framework

    CERN Document Server

    Kagan, Grigory

    2016-01-01

    The recently proposed effective potential theory [Phys. Rev. Lett. 110, 235001 (2013)] allows evaluating transport in coupled plasmas with the well-developed formalisms for systems with binary collisions. To facilitate practical implementation of this concept in fluid models of multi-component plasmas, compact expressions for the transport coefficients in terms the generalized Coulomb logarithms are summarized from existing prescriptions. For weakly coupled plasmas, characterized by Debye-shielded Coulomb interaction potential, expressions become fully analytical. In coupled plasmas the generalized Coulomb logarithms need to be evaluated numerically. Routines implementing the described formalisms are included as supplemental material.

  3. Hypertelescopes: potential science gains, current testing and prospects in space

    Science.gov (United States)

    Labeyrie, A.

    2016-09-01

    In the way of giant dilute telescopes, the hypertelescope is a many-aperture interferometer, which provides direct high resolution images with efficient light concentration. Pending future versions in space, a prototype terrestrial hypertelescope is under test in a high valley of the southern Alps. A moving focal gondola, suspended 101 m above small static mirrors, is driven under computer control with millimeter accuracy. The coude focus at ground level has been qualified by observing a Vega image focused by one of the mirrors and transmitted through the gondola. Upgrades under way for multi-beam interference include full autoguiding, the installation of several cameras on the gondola and adaptive optics for cophasing. Science observing is expected to begin in a few years, and other potential sites are considered for a larger meta-aperture, in the kilometer range. Future space versions, utilizing a 10-1000 km flotilla of small mirrors, are also considered and proposed to NASA and ESA, but require different technical developments.

  4. Effective potential and Goldstone bosons in de Sitter space

    CERN Document Server

    Arai, Takashi

    2013-01-01

    We investigate nonperturbative infrared effects for the O(N) linear sigma model in de Sitter space using the two-particle irreducible effective action at the Hartree truncation level. This approximation resums the infinite series of so-called superdaisy diagrams. For the proper treatment of ultraviolet divergences, we first study the renormalization of this approximation on a general curved background. Then, we calculate radiatively corrected masses and the effective potential. As a result, spontaneous symmetry breaking is possible, on the other hand, the Goldstone modes acquire a positive definite mass term due to the screening effects of interaction. Possible infrared divergence is self-regulated by the mass term. Furthermore, there is a symmetry restoring phase transition as a function of the Hubble parameter. In our approximation, the phase transition is of first order.

  5. Transient dynamics of secondary radiation from an HF pumped magnetized space plasma

    NARCIS (Netherlands)

    Norin, L.; Grach, S. M.; Thide, B.; Sergeev, E. N.; Leyser, T. B.

    2007-01-01

    In order to systematically analyze the transient wave and radiation processes that are excited when a high-frequency (HF) radio wave is injected into a magnetized space plasma, we have measured the secondary radiation, or stimulated electromagnetic emission ( SEE), from the ionosphere, preconditione

  6. Recent results from studies of electron beam phenomena in space plasmas

    Science.gov (United States)

    Neubert, Torsten; Banks, Peter M.

    1992-01-01

    The paper examines selected results from experiments, performed in 1980s, involving the ejection of beams of electrons from spacecraft. Special attention is given to the basic processes associated with the spacecraft charging, passive current collection, beam-atmosphere interactions, beam-plasma interactions, and neutral gas emission. Consideration is also given to future experiments on active electron beam ejections in space.

  7. Ignition of beam plasma discharge in the electron beam experiment in space

    Science.gov (United States)

    Sasaki, S.; Kawashima, N.; Kuriki, K.; Yanagisawa, M.; Roberts, W. T.; Taylor, W. W. L.

    1985-01-01

    An ignition of beam plasma discharge (BPD) in space was observed in a neutral gas-electron beam interaction experiment by Space Shuttle/Spacelab-1 in 1983. An electron beam of 8 kV 100 mA was injected into a high dense nitrogen gas cloud of 10 to the 23rd molecules which was released during 100 msec from the Orbiter. The appearance of the beam and its surroundings observed by a low-light-level TV camera showed a local ignition of the beam plasma discharge in the gas cloud. The enhanced plasma production, generation of auroral emission, and associated wave emission were also detected by onboard diagnostic instruments.

  8. Further observations of Space Shuttle plasma-electrodynamic effects from OSS-1/STS-3

    Science.gov (United States)

    Stone, N. H.; Hwang, K. S.; Wright, K. H., Jr.; Samir, U.; Murphy, G. B.; Shawhan, S. D.

    1986-01-01

    Recent analyses of ion measurements obtained from the Differential Ion Flux Probe (DIFP) on the deployed Plasma Diagnostics Package (PDP) during the OSS-1/STS-3 mission have provided an additional insight into the plasma-electrodynamics of the Space Shuttle Orbiter: (1) Measured ion flow directions and energies suggest that the disturbance created in the ionospheric plasma by the Shuttle Orbiter may be confined to an interaction region that extends on the order of 10 m in the forward direction and has a boundary thickness of about 2 m. (2) A correlation between the DIFP and pressure gauge measurements indicates a direct, local proportionality between the neutral gas and ion densities. (3) Preliminary results from a theoretical model of the possible interaction between measured secondary, high inclination ion streams and the ambient plasma indicate the generation of broad-band electrostatic noise such as that observed by wave instruments on the PDP.

  9. Long-lived laboratory plasmas sustained by a free-space microwave beam

    Science.gov (United States)

    Reid, Remington

    2015-11-01

    The Air Force Research Laboratory is developing a laboratory experiment to study the free-space interaction of microwave beams with low temperature, low density plasmas. A 10 kW, 4.5 GHz beam is passed through a vacuum chamber outfitted with pressure windows that are transparent to 4.5 Ghz radiation. The pressure windows are approximately 1m in diameter, allowing for minimal interaction between the beam and the chamber. The entire experiment is housed inside an anechoic chamber to minimize reflections. Plasmas generated by the beam have been observed to be stable for more than 10s. A series of optical and microwave diagnostics are being developed to measure the plasma properties, and to quantify the interaction of the plasma and the background neutral gas.

  10. Numerical simulations of the electrodynamic interactions between the Tethered-Satellite-System and space plasma

    Science.gov (United States)

    Vashi, Bharat I.

    1992-01-01

    The first Tethered-Satellite-System (TSS-1), scheduled for a flight in late 1992, is expected to provide relevant information related to the concept of generating an emf in a 20-km-long (or longer) conducting wire. This paper presents numerical simulations of the electrodynamic interactions between the TSS system and space plasma, using a 2D and 3D models of the system. The 2D case code simulates the motion of a long cylinder past a plasma, which is composed of electrons and H(+) ions. The system is solved by allowing the plasma to flow past the cylinder with an imposed magnetic field. The more complex 3D case is considered to study the dynamics in great detail. Results of 2D simulation show that the interaction of a satellite with plasma flowing perpendicularly to the magnetic field results in an enhancement in the current collection.

  11. Membrane potential modulates plasma membrane phospholipid dynamics and K-Ras signaling

    Science.gov (United States)

    Zhou, Yong; Wong, Ching-On; Cho, Kwang-jin; van der Hoeven, Dharini; Liang, Hong; Thakur, Dhananiay P.; Luo, Jialie; Babic, Milos; Zinsmaier, Konrad E.; Zhu, Michael X.; Hu, Hongzhen; Venkatachalam, Kartik; Hancock, John F.

    2015-01-01

    Plasma membrane depolarization can trigger cell proliferation, but how membrane potential influences mitogenic signaling is uncertain. Here, we show that plasma membrane depolarization induces nanoscale reorganization of phosphatidylserine and phosphatidylinositol 4,5-bisphosphate but not other anionic phospholipids. K-Ras, which is targeted to the plasma membrane by electrostatic interactions with phosphatidylserine, in turn undergoes enhanced nanoclustering. Depolarization-induced changes in phosphatidylserine and K-Ras plasma membrane organization occur in fibroblasts, excitable neuroblastoma cells, and Drosophila neurons in vivo and robustly amplify K-Ras–dependent mitogen-activated protein kinase (MAPK) signaling. Conversely, plasma membrane repolarization disrupts K-Ras nanoclustering and inhibits MAPK signaling. By responding to voltage-induced changes in phosphatidylserine spatiotemporal dynamics, K-Ras nanoclusters set up the plasma membrane as a biological field-effect transistor, allowing membrane potential to control the gain in mitogenic signaling circuits. PMID:26293964

  12. Experimental investigations of the distribution of pulsed-plasma-generator radiation at its various spatial orientation and global anisotropy of space

    Energy Technology Data Exchange (ETDEWEB)

    Baurov, Yu.A.; Timofeev, I.B.; Chernikov, V.A.; Chalkin, S.F.; Konradov, A.A

    2003-05-26

    Results of experimental investigation of plasma luminous emittance (integrated with respect to time and quartz transmission band spectrum) of a pulsed plasma generator depending on its axis spatial position, are presented. It is shown that the spatial distribution of plasma radiant intensity is of clearly anisotropic character, that is, there exists a cone of the plasma generator axial directions in which the radiation of plasma reaches its peak. A possible explanation of the results obtained based on a hypothesis of global anisotropy of space caused by the existence of a cosmological vectorial potential A{sub g}, is given. It is shown that the vector A{sub g} has the following coordinates in the second equatorial coordinate system: right ascension {alpha}=293 deg. {+-}10 deg., declination {delta}=36 deg. {+-}10 deg. The experimental results are in accordance with those of the earlier experiments on determining the direction of A{sub g}.

  13. Horizontal spacing, depletion, and infill potential in the Austin chalk

    Energy Technology Data Exchange (ETDEWEB)

    Kyte, D.G.; Meehan, D.N.

    1996-12-31

    Estimated ultimate recoveries on a barrels per acre basis for Austin chalk wells were discussed. The study showed that the maximum six months consecutive production through the life of the well can be used to estimate ultimate recovery in horizontally drilled reservoirs. A statistical approach was used to help identify where the Austin chalk has been overdrilled and areas where infill potential exists. The barrels per acre data were analyzed by a method known as `moving domain`. This procedure involves stepping through the reservoir well by well and looking at it with respect to its nearest neighbors. To analyze for depletion, barrels per acre is compared to date of first production for groups of wells in an area, looking for declining values with time. Areas showing no evidence of depletion and having good recoveries are further studied for infill potential. By comparing effective densities in areas which are not yet being fully drained, an optimum spacing between wells can be determined for horizontal wells in a fractured chalk reservoir. An artificial neural network can also be used to provide qualitative predictions of well performance in developed reservoirs. 6 refs., 15 figs.

  14. Molecular Dynamic Studies of Particle Wake Potentials in Plasmas

    Science.gov (United States)

    Ellis, Ian; Graziani, Frank; Glosli, James; Strozzi, David; Surh, Michael; Richards, David; Decyk, Viktor; Mori, Warren

    2010-11-01

    Fast Ignition studies require a detailed understanding of electron scattering, stopping, and energy deposition in plasmas with variable values for the number of particles within a Debye sphere. Presently there is disagreement in the literature concerning the proper description of these processes. Developing and validating proper descriptions requires studying the processes using first-principle electrostatic simulations and possibly including magnetic fields. We are using the particle-particle particle-mesh (P^3M) code ddcMD to perform these simulations. As a starting point in our study, we examined the wake of a particle passing through a plasma. In this poster, we compare the wake observed in 3D ddcMD simulations with that predicted by Vlasov theory and those observed in the electrostatic PIC code BEPS where the cell size was reduced to .03λD.

  15. Diagnostic potential of plasma carboxymethyllysine and carboxyethyllysine in multiple sclerosis

    Directory of Open Access Journals (Sweden)

    Weinstock-Guttmann Bianca

    2010-10-01

    Full Text Available Abstract Background This study compared the level of advanced glycation end products (AGEs, N-(Carboxymethyllysine (CML and N-(Carboxyethyllysine (CEL, in patients with multiple sclerosis (MS and healthy controls (HCs, correlating these markers with clinical indicators of MS disease severity. Methods CML and CEL plasma levels were analyzed in 99 MS patients and 43 HCs by tandem mass spectrometry (LC/MS/MS. Patients were stratified based on drug modifying therapies (DMTs including interferon beta, glatiramer acetate and natalizumab. Results The level of plasma CEL, but not CML, was significantly higher in DMT-naïve MS patients when compared to HCs (P Conclusion Our results suggest that AGEs in general and CEL in particular could be useful biomarkers in MS clinical practice. Longitudinal studies are warranted to determine any causal relationship between changes in plasma level of AGEs and MS disease pathology. These studies will pave the way for use of AGE inhibitors and AGE-breaking agents as new therapeutic modalities in MS.

  16. Nonthermal Argon Plasma Generator and Some Potential Applications

    Directory of Open Access Journals (Sweden)

    Bunoiu M.

    2015-12-01

    Full Text Available A laboratory - made nonthermal plasma generator is presented. It has a diameter of 0.020 m and length of 0.155 m and contains two electrodes. The first electrode is a 2% Th-W alloy, 0.002 m in diameter bar, centred inside the generator’s body by means of a four channel teflon piece; the other three channels, 0.003 m in diameter, are used for Ar supply. The second electrode is a nozzle of 0.002 m - 0.008 m diameter and 0.005m length. A ~500 kV/m electric field is generated between the two electrodes by a high frequency source (13.56 MHz ±5%, equipped with a OT-1000 (Tungsram power triode. For Ar flows ranging from 0.00008 m3/s to 0.00056 m3/s, a plasma jet of length not exceeding 0.015 m and temperature below 315 K is obtained. Anthurium andraeanumis sample , blood matrix, human hair and textile fibers may be introduced in the plasma jet. For time periods of 30 s and 60 s, various effects like, cell detexturization, fast blood coagulation or textile fiber or hair cleaning and smoothing are obtained. These effects are presented and discussed in the paper.

  17. Effective Potential Theory: A Practical Way to Extend Plasma Transport Theory to Strong Coupling

    CERN Document Server

    Baalrud, Scott D; Daligault, Jerome

    2014-01-01

    The effective potential theory is a physically motivated method for extending traditional plasma transport theories to stronger coupling. It is practical in the sense that it is easily incorporated within the framework of the Chapman-Enskog or Grad methods that are commonly applied in plasma physics and it is computationally efficient to evaluate. The extension is to treat binary scatterers as interacting through the potential of mean force, rather than the bare Coulomb or Debye-screened Coulomb potential. This allows for aspects of many-body correlations to be included in the transport coefficients. Recent work has shown that this method accurately extends plasma theory to orders of magnitude stronger coupling when applied to the classical one-component plasma model. The present work shows that similar accuracy is realized for the Yukawa one-component plasma model and it provides a comparison with other approaches.

  18. Plasma physics and the 2013-2022 decadal survey in solar and space physics

    Science.gov (United States)

    Baker, Daniel N.

    2016-11-01

    The U.S. National Academies established in 2011 a steering committee to develop a comprehensive strategy for solar and space physics research. This updated and extended the first (2003) solar and space physics decadal survey. The latest decadal study implemented a 2008 Congressional directive to NASA for the fields of solar and space physics, but also addressed research in other federal agencies. The new survey broadly canvassed the fields of research to determine the current state of the discipline, identified the most important open scientific questions, and proposed the measurements and means to obtain them so as to advance the state of knowledge during the years 2013-2022. Research in this field has sought to understand: dynamical behaviour of the Sun and its heliosphere; properties of the space environments of the Earth and other solar system bodies; multiscale interaction between solar system plasmas and the interstellar medium; and energy transport throughout the solar system and its impact on the Earth and other solar system bodies. Research in solar and space plasma processes using observation, theory, laboratory studies, and numerical models has offered the prospect of understanding this interconnected system well enough to develop a predictive capability for operational support of civil and military space systems. We here describe the recommendations and strategic plans laid out in the 2013-2022 decadal survey as they relate to measurement capabilities and plasma physical research. We assess progress to date. We also identify further steps to achieve the Survey goals with an emphasis on plasma physical aspects of the program.

  19. A Polytropic Model for Space and Laboratory Plasmas Described by Bi-Maxwellian Electron Distributions

    Science.gov (United States)

    Zhang, Yunchao; Charles, Christine; Boswell, Rod

    2016-09-01

    Non-local electron energy probability functions (EEPFs) are shown to have an important effect on the thermodynamic behavior of plasmas in the context of solar wind and laboratory plasmas. A conservation relation is held for electron enthalpy and plasma potential during the electron transport. For an adiabatic system governed by non-local electron dynamics, the correlation between electron temperature and density can be approximated by a polytropic relation, with different indexes demonstrated using three cases of bi-Maxwellian EEPFs. This scenario differs from a local thermodynamic equilibrium having a single polytropic index of 5/3 for adiabaticity.

  20. Interpretation of fast measurements of plasma potential, temperature and density in SOL of ASDEX Upgrade

    DEFF Research Database (Denmark)

    Horacek, J.; Adamek, J.; Müller, H.W.

    2010-01-01

    This paper focuses on interpretation of fast (1 µs) and local (2–4 mm) measurements of plasma density, potential and electron temperature in the edge plasma of tokamak ASDEX Upgrade. Steady-state radial profiles demonstrate the credibility of the ball-pen probe. We demonstrate that floating poten...

  1. Low Frequency Turbulence as the Source of High Frequency Waves in Multi-Component Space Plasmas

    Science.gov (United States)

    Khazanov, George V.; Krivorutsky, Emmanuel N.; Uritsky, Vadim M.

    2011-01-01

    Space plasmas support a wide variety of waves, and wave-particle interactions as well as wavewave interactions are of crucial importance to magnetospheric and ionospheric plasma behavior. High frequency wave turbulence generation by the low frequency (LF) turbulence is restricted by two interconnected requirements: the turbulence should be strong enough and/or the coherent wave trains should have the appropriate length. These requirements are strongly relaxed in the multi-component plasmas, due to the heavy ions large drift velocity in the field of LF wave. The excitation of lower hybrid waves (LHWs), in particular, is a widely discussed mechanism of interaction between plasma species in space and is one of the unresolved questions of magnetospheric multi-ion plasmas. It is demonstrated that large-amplitude Alfven waves, in particular those associated with LF turbulence, may generate LHW s in the auroral zone and ring current region and in some cases (particularly in the inner magnetosphere) this serves as the Alfven wave saturation mechanism. We also argue that the described scenario can playa vital role in various parts of the outer magnetosphere featuring strong LF turbulence accompanied by LHW activity. Using the data from THEMIS spacecraft, we validate the conditions for such cross-scale coupling in the near-Earth "flow-braking" magnetotail region during the passage of sharp injection/dipolarization fronts, as well as in the turbulent outflow region of the midtail reconnection site.

  2. Study of magnetic field expansion using a plasma generator for space radiation active protection

    Institute of Scientific and Technical Information of China (English)

    JIA Xiang-Hong; JIA Shao-Xia; XU Feng; BAI Yan-Qiang; WAN Jun; LIU Hong-Tao; JIANG Rui

    2013-01-01

    There are many active protecting methods including Electrostatic Fields,Confined Magnetic Field,Unconfined Magnetic Field and Plasma Shielding etc.for defending the high-energy solar particle events (SPE) and Galactic Cosmic Rays (GCR) in deep space exploration.The concept of using cold plasma to expand a magnetic field is the best one of all possible methods so far.The magnetic field expansion caused by plasma can improve its protective efficiency of space particles.One kind of plasma generator has been developed and installed into the cylindrical permanent magnet in the eccentric.A plasma stream is produced using a helical-shaped antenna driven by a radio-frequency (RF) power supply of 13.56 MHz,which exits from both sides of the magnet and makes the magnetic field expand on one side.The discharging belts phenomenon is similar to the Earth's radiation belt,but the mechanism has yet to be understood.A magnetic probe is used to measure the magnetic field expansion distributions,and the results indicate that the magnetic field intensity increases under higher increments of the discharge power.

  3. Kinematic dust viscosity effect on linear and nonlinear dust-acoustic waves in space dusty plasmas with nonthermal ions

    Energy Technology Data Exchange (ETDEWEB)

    El-Hanbaly, A. M.; Sallah, M., E-mail: msallahd@mans.edu.eg [Mansoura University, Physics Department, Faculty of Science (Egypt); El-Shewy, E. K. [Taibah University Al-Madinah Al-Munawarah, Department of Physics (Saudi Arabia); Darweesh, H. F. [Mansoura University, Physics Department, Faculty of Science (Egypt)

    2015-10-15

    Linear and nonlinear dust-acoustic (DA) waves are studied in a collisionless, unmagnetized and dissipative dusty plasma consisting of negatively charged dust grains, Boltzmann-distributed electrons, and nonthermal ions. The normal mode analysis is used to obtain a linear dispersion relation illustrating the dependence of the wave damping rate on the carrier wave number, the dust viscosity coefficient, the ratio of the ion temperature to the electron temperatures, and the nonthermal parameter. The plasma system is analyzed nonlinearly via the reductive perturbation method that gives the KdV-Burgers equation. Some interesting physical solutions are obtained to study the nonlinear waves. These solutions are related to soliton, a combination between a shock and a soliton, and monotonic and oscillatory shock waves. Their behaviors are illustrated and shown graphically. The characteristics of the DA solitary and shock waves are significantly modified by the presence of nonthermal (fast) ions, the ratio of the ion temperature to the electron temperature, and the dust kinematic viscosity. The topology of the phase portrait and the potential diagram of the KdV-Burgers equation is illustrated, whose advantage is the ability to predict different classes of traveling wave solutions according to different phase orbits. The energy of the soliton wave and the electric field are calculated. The results in this paper can be generalized to analyze the nature of plasma waves in both space and laboratory plasma systems.

  4. Space-Time Localization of Plasma Turbulence Using Multiple Spacecraft Radio Links

    Science.gov (United States)

    Armstrong, John W.; Estabrook, Frank B.

    2011-01-01

    Space weather is described as the variability of solar wind plasma that can disturb satellites and systems and affect human space exploration. Accurate prediction requires information of the heliosphere inside the orbit of the Earth. However, for predictions using remote sensing, one needs not only plane-of-sky position but also range information the third spatial dimension to show the distance to the plasma disturbances and thus when they might propagate or co-rotate to create disturbances at the orbit of the Earth. Appropriately processed radio signals from spacecraft having communications lines-of-sight passing through the inner heliosphere can be used for this spacetime localization of plasma disturbances. The solar plasma has an electron density- and radio-wavelength-dependent index of refraction. An approximately monochromatic wave propagating through a thin layer of plasma turbulence causes a geometrical-optics phase shift proportional to the electron density at the point of passage, the radio wavelength, and the thickness of the layer. This phase shift is the same for a wave propagating either up or down through the layer at the point of passage. This attribute can be used for space-time localization of plasma irregularities. The transfer function of plasma irregularities to the observed time series depends on the Doppler tracking mode. When spacecraft observations are in the two-way mode (downlink radio signal phase-locked to an uplink radio transmission), plasma fluctuations have a two-pulse response in the Doppler. In the two-way mode, the Doppler time series y2(t) is the difference between the frequency of the downlink signal received and the frequency of a ground reference oscillator. A plasma blob localized at a distance x along the line of sight perturbs the phase on both the up and down link, giving rise to two events in the two-way tracking time series separated by a time lag depending the blob s distance from the Earth: T2-2x/c, where T2 is the

  5. Non-Uniform Plasma Discharges in Near Earth Space Environment and Ionosphere to Troposphere Responses

    Science.gov (United States)

    McCanney, J. M.

    2009-05-01

    excess current of protons in the solar wind, which creates an overall capacitor with inherent non-uniform electric field surrounding the Sun. On a local scale the voltage gradients are quite low, but all objects in this solar capacitor, including the planets and their moon systems, discharge this capacitor over extensive trans-planetary distances, thus creating excessive current flows, which also respond to CMEs and solar flares which carry a far greater potential gradient in the passing solar wind. The key to understanding reactions to non-uniform electric fields in the LEB environment is based on the fact that planetary Debye shielding takes on a new form, which is extended from that of the neutral environment typically considered in previous theoretical models. An attempt is made to solve the fundamental problem of the source of energy that drives these systems. The effects of moons and their positions relative to the planet and solar wind, as well as multiple planetary electrical alignments, are shown to contribute to the overall discharge phenomenon. A connection is made between these energy sources and cyclonic storms, earthquakes and volcanic "trigger" mechanisms. The goal of this research is to create an overall space weather model that couples the single energy source (the non-uniform plasma environment of the Sun created by an excess current of positive charge in the solar wind) to the earth's magnetosphere and ionosphere (and other planetary environments) and ultimately to the low altitude weather systems.

  6. Critical points in the 16-moment approximation. [plasma flow in laboratory and space plasmas study

    Science.gov (United States)

    Yasseen, F.; Retterer, J. M.

    1991-01-01

    The singular points in steady state, field-aligned plasma transport models based on velocity moment theory are examined. In particular, two separate singular points in the equations obtained from the 16-moment approximation are identified. These equations are presented in a form that makes the singularities apparent, and they are solved in a simple illustrative case. The singular points, one occurring at the sonic point and the other at a critical value of the parallel heat flux, give rise to different outflow regimes, characterized generically by different asymptotic behavior. The existence of the different outflow regimes separated by the heat flux critical point has been only hinted at in previous discussions of numerical simulation of the polar wind.

  7. Unified study of plasma-surface interactions for space power and propulsion

    Science.gov (United States)

    Turchi, P. J.; Davis, J. F., III; Norwood, J., Jr.; Boyer, C. N.

    1985-02-01

    The efficiency and lifetime of high specific power/high specific impulse space power and propulsion devices often depend on particle and energy transport at electrodes and insulators in low temperature plasma flows. Actual measurements of particle and field distributions near solid surfaces in controlled plasma flows were studied and used to develop models for particle and energy transport. A unique advantage in such model development is the ability to vary flow conditions, surface orientation, and material properties and to compare data within a unified experimental framework, thereby allowing complicated interactions to be delineated.

  8. Determination of albumin transport rate between plasma and peritoneal space in decompensated cirrhosis

    DEFF Research Database (Denmark)

    Ring-Larsen, H; Henriksen, Jens Henrik Sahl

    1984-01-01

    the abdominal puncture may lead to overestimation of TERperit.space, whereas systematic understimation seems less likely. This may besides differences in patient selection and unsteady state, account for the discrepancy between the present relatively low value and earlier reports on much higher values.......10-0.59). The transport rate of albumin from ascitic fluid back to plasma was measured in eight patients by plasma sampling after intraperitoneal injection of 131I-labelled serum albumin. After correction for tracer re-extravasation this back transport (median 0.31, range 0.07-0.44% IVM/h-1) was not significantly...

  9. Characterization of SOL plasma flows and potentials in ICRF-heated plasmas in Alcator C-mod

    Science.gov (United States)

    Hong, R.; Wukitch, S. J.; Lin, Y.; Terry, J. L.; Cziegler, I.; Reinke, M. L.; Tynan, G. R.

    2017-10-01

    Gas-puff imaging techniques are employed to determine the far SOL region radial electric field and the plasma potential in ICRF heated discharges in the Alcator C-Mod tokamak. The two-dimensional velocity fields of the turbulent structures, which are advected by RF-induced {E}× {B} flows, are obtained via the time-delay estimation (TDE) techniques. Both the magnitude and radial extension of the radial electric field E r are observed to increase with the toroidal magnetic field strength B φ and the ICRF power. In particular, the RF-induced E r extends from the vicinity of the ICRF antenna to the separatrix when {B}\\varphi =7.9 {{T}} and {P}{ICRF}≳ 1 {MW}. In addition, low-Z impurity seeding near the antenna is found to substantially reduce the sheath potential associated with ICRF power. The TDE techniques have also been used to revisit and estimate ICRF-induced potentials in different antenna configurations: (1) conventional toroidally aligned (TA) antenna versus field-aligned (FA) antenna; (2) FA monopole versus FA dipole. It shows that FA and TA antennas produce similar magnitude of plasma potentials, and the FA monopole induced greater potential than the FA dipole phasing. The TDE estimations of RF-induced plasma potentials are consistent with previous results based on the poloidal phase velocity.

  10. Overview of Space Station attached payloads in the areas of solar physics, solar terrestrial physics, and plasma processes

    Science.gov (United States)

    Roberts, W. T.; Kropp, J.; Taylor, W. W. L.

    1986-01-01

    This paper outlines the currently planned utilization of the Space Station to perform investigations in solar physics, solar terrestrial physics, and plasma physics. The investigations and instrumentation planned for the Solar Terrestrial Observatory (STO) and its associated Space Station accommodation requirements are discussed as well as the planned placement of the STO instruments and typical operational scenarios. In the area of plasma physics, some preliminary plans for scientific investigations and for the accommodation of a plasma physics facility attached to the Space Station are outlined. These preliminary experiment concepts use the space environment around the Space Station as an unconfined plasma laboratory. In solar physics, the initial instrument complement and associated accommodation requirements of the Advanced Solar Observatory are described. The planned evolutionary development of this observatory is outlined, making use of the Space Station capabilities for servicing and instrument reconfiguration.

  11. Cytotoxic and mutagenic potential of solutions exposed to cold atmospheric plasma.

    Science.gov (United States)

    Boehm, Daniela; Heslin, Caitlin; Cullen, Patrick J; Bourke, Paula

    2016-01-01

    The exposure of aqueous solutions to atmospheric plasmas results in the generation of relatively long-lived secondary products such as hydrogen peroxide which are biologically active and have demonstrated anti-microbial and cytotoxic activity. The use of plasma-activated solutions in applications such as microbial decontamination or anti-cancer treatments requires not only adequate performance on target cells but also a safe operating window regarding the impact on surrounding tissues. Furthermore the generation of plasma-activated fluids needs to be considered as a by-stander effect of subjecting tissue to plasma discharges. Cytotoxicity and mutagenicity assays using mammalian cell lines were used to elucidate the effects of solutions treated with di-electric barrier discharge atmospheric cold plasma. Plasma-treated PBS inhibited cell growth in a treatment time-dependent manner showing a linear correlation to the solutions' peroxide concentration which remained stable over several weeks. Plasma-treated foetal bovine serum (FBS) acting as a model for complex bio-fluids showed not only cytotoxic effects but also exhibited increased mutagenic potential as determined using the mammalian HPRT assay. Further studies are warranted to determine the nature, causes and effects of the cyto- and genotoxic potential of solutions exposed to plasma discharges to ensure long-term safety of novel plasma applications in medicine and healthcare.

  12. Controlled Electron Injection into Plasma Accelerators and SpaceCharge Estimates

    Energy Technology Data Exchange (ETDEWEB)

    Fubiani, Gwenael G.J. [Univ. of California, Berkeley, CA (United States)

    2005-09-01

    Plasma based accelerators are capable of producing electron sources which are ultra-compact (a few microns) and high energies (up to hundreds of MeVs) in much shorter distances than conventional accelerators. This is due to the large longitudinal electric field that can be excited without the limitation of breakdown as in RF structures.The characteristic scale length of the accelerating field is the plasma wavelength and for typical densities ranging from 1018 - 1019 cm-3, the accelerating fields and scale length can hence be on the order of 10-100GV/m and 10-40 μm, respectively. The production of quasimonoenergetic beams was recently obtained in a regime relying on self-trapping of background plasma electrons, using a single laser pulse for wakefield generation. In this dissertation, we study the controlled injection via the beating of two lasers (the pump laser pulse creating the plasma wave and a second beam being propagated in opposite direction) which induce a localized injection of background plasma electrons. The aim of this dissertation is to describe in detail the physics of optical injection using two lasers, the characteristics of the electron beams produced (the micrometer scale plasma wavelength can result in femtosecond and even attosecond bunches) as well as a concise estimate of the effects of space charge on the dynamics of an ultra-dense electron bunch with a large energy spread.

  13. Development of a power electronics unit for the Space Station plasma contactor

    Science.gov (United States)

    Hamley, John A.; Hill, Gerald M.; Patterson, Michael J.; Saggio, Joseph, Jr.; Terdan, Fred; Mansell, Justin D.

    1994-02-01

    A hollow cathode plasma contactor has been baselined as a charge control device for the Space Station (SS) to prevent deleterious interactions of coated structural components with the ambient plasma. NASA LeRC Work Package 4 initiated the development of a plasma contactor system comprised of a Power Electronics Unit (PEU), an Expellant Management Unit (EMU), a command and data interface, and a Plasma Contactor Unit (PCU). A breadboard PEU was designed and fabricated. The breadboard PEU contains a cathode heater and discharge power supply, which were required to operate the PCU, a control and auxiliary power converter, an EMU interface, a command and telemetry interface, and a controller. The cathode heater and discharge supplies utilized a push-pull topology with a switching frequency of 20 kHz and pulse-width-modulated (PWM) control. A pulse ignition circuit derived from that used in arcjet power processors was incorporated in the discharge supply for discharge ignition. An 8088 based microcontroller was utilized in the breadboard model to provide a flexible platform for controller development with a simple command/data interface incorporating a direct connection to SS Mulitplexer/Demultiplexer (MDM) analog and digital I/O cards. Incorporating this in the flight model would eliminate the hardware and software overhead associated with a 1553 serial interface. The PEU autonomously operated the plasma contactor based on command inputs and was successfully integrated with a prototype plasma contactor unit demonstrating reliable ignition of the discharge and steady-state operation.

  14. Empirical modeling of plasma clouds produced by the Metal Oxide Space Clouds experiment

    Science.gov (United States)

    Pedersen, Todd R.; Caton, Ronald G.; Miller, Daniel; Holmes, Jeffrey M.; Groves, Keith M.; Sutton, Eric

    2017-05-01

    The Advanced Research Project Agency (ARPA) Long-Range Tracking And Instrumentation Radar (ALTAIR) radar at Kwajalein Atoll was used in incoherent scatter mode to measure plasma densities within two artificial clouds created by the Air Force Research Laboratory (AFRL) Metal Oxide Space Clouds (MOSC) experiment in May 2013. Optical imager, ionosonde, and ALTAIR measurements were combined to create 3-D empirical descriptions of the plasma clouds as a function of time, which match the radar measurements to within 15%. The plasma clouds closely track the location of the optical clouds, and the best fit plasma cloud widths are generally consistent with isotropic neutral diffusion. Cloud plasma densities decreased as a power of time, with exponents between -0.5 and -1.0, or much more slowly than the -1.5 predicted by diffusion. These exponents and estimates of total ion number from integration through the model volume are consistent with a scenario of slow ionization and a gradually increasing total number of ions with time, reaching a net ionization fraction of 20% after approximately half an hour. These robust representations of the plasma density are being used to study impacts of the artificial clouds on the dynamics of the background ionosphere and on RF propagation.

  15. Status of Hollow Cathode Heater Development for the Space Station Plasma Contactor

    Science.gov (United States)

    Soulas, George C.

    1994-01-01

    A hollow cathode-based plasma contactor has been selected for use on the Space Station. During the operation of the plasma contactor, the hollow cathode heater will endure approximately 12000 thermal cycles. Since a hollow cathode heater failure would result in a plasma contactor failure, a hollow cathode heater development program was established to produce a reliable heater. The development program includes the heater design, process documents for both heater fabrication and assembly, and heater testing. The heater design was a modification of a sheathed ion thruster cathode heater. Heater tests included testing of the heater unit alone and plasma contactor and ion thruster testing. To date, eight heaters have been or are being processed through heater unit testing, two through plasma contactor testing and three through ion thruster testing, all using direct current power supplies. Comparisons of data from heater unit performance tests before cyclic testing, plasma contactor tests, and ion thruster tests at the ignition input current level show the average deviation of input power and tube temperature near the cathode tip to be +/-0.9 W and +/- 21 C, respectively. Heater unit testing included cyclic testing to evaluate reliability under thermal cycling. The first heater, although damaged during assembly, completed 5985 ignition cycles before failing. Four additional heaters successfully completed 6300, 6300, 700, and 700 cycles. Heater unit testing is currently ongoing for three heaters which have to date accumulated greater than 7250, greater than 5500, and greater than 5500 cycles, respectively.

  16. Development of a Power Electronics Unit for the Space Station Plasma Contactor

    Science.gov (United States)

    Hamley, John A.; Hill, Gerald M.; Patterson, Michael J.; Saggio, Joseph, Jr.; Terdan, Fred; Mansell, Justin D.

    1994-01-01

    A hollow cathode plasma contactor has been baselined as a charge control device for the Space Station (SS) to prevent deleterious interactions of coated structural components with the ambient plasma. NASA LeRC Work Package 4 initiated the development of a plasma contactor system comprised of a Power Electronics Unit (PEU), an Expellant Management Unit (EMU), a command and data interface, and a Plasma Contactor Unit (PCU). A breadboard PEU was designed and fabricated. The breadboard PEU contains a cathode heater and discharge power supply, which were required to operate the PCU, a control and auxiliary power converter, an EMU interface, a command and telemetry interface, and a controller. The cathode heater and discharge supplies utilized a push-pull topology with a switching frequency of 20 kHz and pulse-width-modulated (PWM) control. A pulse ignition circuit derived from that used in arcjet power processors was incorporated in the discharge supply for discharge ignition. An 8088 based microcontroller was utilized in the breadboard model to provide a flexible platform for controller development with a simple command/data interface incorporating a direct connection to SS Mulitplexer/Demultiplexer (MDM) analog and digital I/O cards. Incorporating this in the flight model would eliminate the hardware and software overhead associated with a 1553 serial interface. The PEU autonomously operated the plasma contactor based on command inputs and was successfully integrated with a prototype plasma contactor unit demonstrating reliable ignition of the discharge and steady-state operation.

  17. Space-frequency analysis and reduction of potential field ambiguity

    Directory of Open Access Journals (Sweden)

    A. Rapolla

    1997-06-01

    Full Text Available Ambiguity of depth estimation of magnetic sources via spectral analysis can be reduced representing its field via a set of space-frequency atoms. This is obtained throughout a continuous wavelet transform using a Morlet analyzing wavelet. In the phase-plane representation even a weak contribution related to deep-seated sources is clearly distinguished with respect a more intense effect of a shallow source, also in the presence of a strong noise. Furthermore, a new concept of local power spectrum allows the depth to both the sources to be correctly interpreted. Neither result can be provided by standard Fourier analysis. Another method is proposed to reduce ambiguity by inversion of potential field data lying along the vertical axis. This method allows a depth resolution to gravity or the magnetic methods and below some conditions helps to reduce their inherent ambiguity. Unlike the case of monopoles, inversion of a vertical profile of gravity data above a cubic source gives correct results for the cube side and density.

  18. Transport and trapping of dust particles in a potential well created by inductively coupled diffused plasma

    CERN Document Server

    Choudhary, Mangilal; Bandyopadhyay, P

    2016-01-01

    A versatile linear dusty (complex) plasma device is designed to study the transport and dynamical behavior of dust particles in a large volume. Diffused inductively coupled plasma is generated in the background of argon gas. A novel technique is used to introduce the dust particles in the main plasma by striking a secondary direct current (DC) glow discharge. These dust particles are found to get trapped in an electrostatic potential well which is formed due to the combination of the ambipolar electric field caused by diffusive plasma and the field produced by the charged glass wall of the vacuum chamber. According to the requirements, the volume of the dust cloud can be controlled very precisely by tuning the plasma and discharge parameters. The present device can be used to address the underlying physics behind the transport of dust particles, self excited dust acoustic waves and instabilities. The detailed design of this device, plasma production and characterization, trapping and transport of the dust par...

  19. Ionospheric plasma flow over large high-voltage space platforms. I - Ion-plasma-time scale interactions of a plate at zero angle of attack. II - The formation and structure of plasma wake

    Science.gov (United States)

    Wang, J.; Hastings, D. E.

    1992-01-01

    The paper presents the theory and particle simulation results for the ionospheric plasma flow over a large high-voltage space platform at a zero angle of attack and at a large angle of attack. Emphasis is placed on the structures in the large, high-voltage regime and the transient plasma response on the ion-plasma time scale. Special consideration is given to the transient formation of the space-charge wake and its steady-state structure.

  20. Results of direct measurements of the plasma potential using a laser-heated emissive probe

    Energy Technology Data Exchange (ETDEWEB)

    Schrittwieser, R.; Sarma, A.; Amarandei, G.; Ionita, C. [Univ. of Innsbruck (Austria). Inst. for Ion Physics; Klinger, T.; Grulke, O.; Vogelsang, A.; Windisch, T. [Max Planck Inst. for Plasma Physics, Greifswald (Germany)

    2006-04-15

    Reliable diagnostics of the plasma potential is one of the most important challenges in context with the production, control and confinement of a plasma. Emissive probes are readily available as direct diagnostic tools for the plasma potential with a good temporal and spatial resolution in many plasmas, even up to middle-sized fusion experiments. We present the results of investigations on the heating of lanthanum hexaboride and graphite with an infrared diode laser and on the development of a laser-heated emissive probe. Such a probe has a higher electron emission, much longer life time and better time response than a conventional emissive wire probe. We have observed that from both materials electron emission current can be achieved sufficiently strongly even for dense laboratory and experimental fusion plasmas.

  1. Levitation and Oscillation of Dust Grains in Plasma Sheath with Wake Potential

    Institute of Scientific and Technical Information of China (English)

    练海俊; 谢柏松; 周宏余

    2002-01-01

    We investigate the equilibrium and levitation of dust grains in a plasma sheath with various forces, in particular the wake potential force. The vertical oscillation frequency of dust chains is also obtained by including the wake potential term. It is found that the wake potential has a significant role for the levitation and oscillation of dust grains.

  2. Parameterizing the Morse potential for coarse-grained modeling of blood plasma

    Science.gov (United States)

    Zhang, Na; Zhang, Peng; Kang, Wei; Bluestein, Danny; Deng, Yuefan

    2014-01-01

    Multiscale simulations of fluids such as blood represent a major computational challenge of coupling the disparate spatiotemporal scales between molecular and macroscopic transport phenomena characterizing such complex fluids. In this paper, a coarse-grained (CG) particle model is developed for simulating blood flow by modifying the Morse potential, traditionally used in Molecular Dynamics for modeling vibrating structures. The modified Morse potential is parameterized with effective mass scales for reproducing blood viscous flow properties, including density, pressure, viscosity, compressibility and characteristic flow dynamics of human blood plasma fluid. The parameterization follows a standard inverse-problem approach in which the optimal micro parameters are systematically searched, by gradually decoupling loosely correlated parameter spaces, to match the macro physical quantities of viscous blood flow. The predictions of this particle based multiscale model compare favorably to classic viscous flow solutions such as Counter-Poiseuille and Couette flows. It demonstrates that such coarse grained particle model can be applied to replicate the dynamics of viscous blood flow, with the advantage of bridging the gap between macroscopic flow scales and the cellular scales characterizing blood flow that continuum based models fail to handle adequately.

  3. Parameterizing the Morse potential for coarse-grained modeling of blood plasma

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Na [Department of Applied Mathematics and Statistics, Stony Brook University, NY 11794 (United States); Zhang, Peng [Department of Biomedical Engineering, Stony Brook University, NY 11790 (United States); Kang, Wei [Center for Applied Physics and Technology, College of Engineering, Peking University, Beijing 100871 (China); Bluestein, Danny [Department of Biomedical Engineering, Stony Brook University, NY 11790 (United States); Deng, Yuefan, E-mail: Yuefan.Deng@StonyBrook.edu [Department of Applied Mathematics and Statistics, Stony Brook University, NY 11794 (United States)

    2014-01-15

    Multiscale simulations of fluids such as blood represent a major computational challenge of coupling the disparate spatiotemporal scales between molecular and macroscopic transport phenomena characterizing such complex fluids. In this paper, a coarse-grained (CG) particle model is developed for simulating blood flow by modifying the Morse potential, traditionally used in Molecular Dynamics for modeling vibrating structures. The modified Morse potential is parameterized with effective mass scales for reproducing blood viscous flow properties, including density, pressure, viscosity, compressibility and characteristic flow dynamics of human blood plasma fluid. The parameterization follows a standard inverse-problem approach in which the optimal micro parameters are systematically searched, by gradually decoupling loosely correlated parameter spaces, to match the macro physical quantities of viscous blood flow. The predictions of this particle based multiscale model compare favorably to classic viscous flow solutions such as Counter-Poiseuille and Couette flows. It demonstrates that such coarse grained particle model can be applied to replicate the dynamics of viscous blood flow, with the advantage of bridging the gap between macroscopic flow scales and the cellular scales characterizing blood flow that continuum based models fail to handle adequately.

  4. Ensemble Space-Time Correlation of Plasma Turbulence in the Solar Wind.

    Science.gov (United States)

    Matthaeus, W H; Weygand, J M; Dasso, S

    2016-06-17

    Single point measurement turbulence cannot distinguish variations in space and time. We employ an ensemble of one- and two-point measurements in the solar wind to estimate the space-time correlation function in the comoving plasma frame. The method is illustrated using near Earth spacecraft observations, employing ACE, Geotail, IMP-8, and Wind data sets. New results include an evaluation of both correlation time and correlation length from a single method, and a new assessment of the accuracy of the familiar frozen-in flow approximation. This novel view of the space-time structure of turbulence may prove essential in exploratory space missions such as Solar Probe Plus and Solar Orbiter for which the frozen-in flow hypothesis may not be a useful approximation.

  5. Control of magnetohydrodynamic stability by phase space engineering of energetic ions in tokamak plasmas.

    Science.gov (United States)

    Graves, J P; Chapman, I T; Coda, S; Lennholm, M; Albergante, M; Jucker, M

    2012-01-10

    Virtually collisionless magnetic mirror-trapped energetic ion populations often partially stabilize internally driven magnetohydrodynamic disturbances in the magnetosphere and in toroidal laboratory plasma devices such as the tokamak. This results in less frequent but dangerously enlarged plasma reorganization. Unique to the toroidal magnetic configuration are confined 'circulating' energetic particles that are not mirror trapped. Here we show that a newly discovered effect from hybrid kinetic-magnetohydrodynamic theory has been exploited in sophisticated phase space engineering techniques for controlling stability in the tokamak. These theoretical predictions have been confirmed, and the technique successfully applied in the Joint European Torus. Manipulation of auxiliary ion heating systems can create an asymmetry in the distribution of energetic circulating ions in the velocity orientated along magnetic field lines. We show the first experiments in which large sawtooth collapses have been controlled by this technique, and neoclassical tearing modes avoided, in high-performance reactor-relevant plasmas.

  6. To Mars and beyond, fast! how plasma propulsion will revolutionize space exploration

    CERN Document Server

    Chang Díaz, Franklin

    2017-01-01

    As advanced space propulsion moves slowly from science fiction to achievable reality, the Variable Specific Impulse Magnetoplasma Rocket, or VASIMR, is a leading contender for making 'Mars in a month' a possibility. Developed by Ad Astra Rockets, which was founded by astronaut Franklin Chang-Diaz and backed by NASA, its first commercial tests are imminent. VASIMR heats plasma to extreme temperatures using radio waves. Strong magnetic fields then funnel this plasma out the back of the engine, creating thrust. The continuous propulsion may place long, fast interplanetary journeys within reach in the near future. While scientists dream of the possibilities of using fusion or well-controlled matter-antimatter interactions to propel spacecraft fast and far, that goal is still some way over the horizon. VASIMR provides a more attainable propulsion technology that is based on the matter-antimatter concept. The book describes a landmark technology grounded in plasma physics and offering a practical technological solu...

  7. The Electron Firehose and Ordinary-Mode Instabilities in Space Plasmas

    CERN Document Server

    Lazar, M; Schlickeiser, R; Ibscher, D

    2013-01-01

    The selfgenerated wave fluctuations are particularly interesting in the solar wind and magnetospheric plasmas, where Coulomb collisions are rare and cannot explain the observed states of quasi-equilibrium. Linear theory predicts that the firehose and the ordinary-mode instabilities can develop under the same conditions, confusing the role of these instabilities in conditioning the space-plasma properties. The hierarchy of these two instabilities is reconsidered here for nonstreaming plasmas with an electron temperature anisotropy $T_\\parallel > T_\\perp$, where $\\parallel$ and $\\perp$ denote directions with respect to the local mean magnetic field. In addition to the previous comparative analysis, here the entire 3D wave-vector spectrum of the competing instabilities is investigated, paying particular attention to the oblique firehose instability and the relatively poorly known ordinary-mode instability. Results show a dominance of the oblique firehose instability with a threshold lower than the parallel fireh...

  8. Dynamics of magnetically trapped particles foundations of the physics of radiation belts and space plasmas

    CERN Document Server

    Roederer, Juan G

    2014-01-01

    This book is a new edition of Roederer’s classic Dynamics of Geomagnetically Trapped Radiation, updated and considerably expanded. The main objective is to describe the dynamic properties of magnetically trapped particles in planetary radiation belts and plasmas and explain the physical processes involved from the theoretical point of view. The approach is to examine in detail the orbital and adiabatic motion of individual particles in typical configurations of magnetic and electric fields in the magnetosphere and, from there, derive basic features of the particles’ collective “macroscopic” behavior in general planetary environments. Emphasis is not on the “what” but on the “why” of particle phenomena in near-earth space, providing a solid and clear understanding of the principal basic physical mechanisms and dynamic processes involved. The book will also serve as an introduction to general space plasma physics, with abundant basic examples to illustrate and explain the physical origin of diff...

  9. Active probing of space plasmas. Final report, 25 October 1985-30 September 1989

    Energy Technology Data Exchange (ETDEWEB)

    Chan, C.; Silevitch, M.B.; Villalon, E.

    1989-09-01

    During the course of the research period our efforts were focused on the following areas: (1) An examination of stochastic acceleration mechanisms in the ionosphere; (2) A study of nonequilibrium dynamics of the coupled magnetosphere - ionosphere system; and (3) Laboratory studies of active space experiments. Reprints include: Dynamics of charged particles in the near wake of a very negatively charged body -- Laboratory experiment and numerical simulation; Laboratory study of the electron temperature in the near wake of a conducting body; New model for auroral breakup during substorms; Substorm breakup on closed field lines; New model for substorm on sets -- The pre-breakup and triggering regimes; Model of the westward traveling surge and the generation of Pi 2 pulsations; Ionospheric electron acceleration by electromagnetic waves near regions of plasma resonances; Relativistic particle acceleration by obliquely propagating electromagnetic fields; Some consequences of intense electromagnetic wave injection into space plasmas.

  10. Beam Phase Space of an Intense Ion Beam in a Neutralizing Plasma

    Science.gov (United States)

    Seidl, Peter A.; Bazouin, Guillaume; Beneytout, Alice; Lidia, Steven M.; Vay, Jean-Luc; Grote, David P.

    2011-10-01

    The Neutralized Drift Compression Experiment (NDCX-I) generates high intensity ion beams to explore warm dense matter physics. Transverse final focusing is accomplished with an 8-Tesla, 10-cm long pulsed solenoid magnet combined with a background neutralizing plasma to effectively cancel the space charge field of the ion beam. We report on phase space measurements of the beam before the neutralization channel and of the focused ion beam at the target plane. These are compared to WARP particle-in-cell simulations of the ion beam propagation through the focusing system and neutralizing plasma. Due to the orientation of the plasma sources with respect to the focusing magnet, the plasma distribution within the final focusing lens is strongly affected by the magnetic field, an effect which can influence the peak intensity at the target and which is included in the model of the experiment. Work performed under auspices of U.S. DoE by LLNL, LBNL under Contracts DE-AC52-07NA27344, DE-AC02-05CH1123.

  11. Space Management: Promising Potentials through a Comprehensive Information Data Base.

    Science.gov (United States)

    Sherman, Douglas R.

    Comprehensive facility management databases designed by the Facility Management Institute of Ann Arbor (Michigan) have three major sections or "files": the space inventory file, the property control file, and the building and grounds file. The first two are alpha-numeric in design, while the third is essentially a graphic file. The space inventory…

  12. Clarification on Polarity of Bipolar Electric Field Solitary Structures in Space Plasmas with Satellite Observation

    Institute of Scientific and Technical Information of China (English)

    M. N. S.Qureshi; SHI Jian-Kui; LIU Zhen-Xing; Klaus Torkar

    2011-01-01

    The bipolar electric field solitary (EFS) structures observed frequently in space plasmas by satellites have two different polarities, first positive electric field peak then negative (i.e., positive/negative) and first negative then positive peak (i.e., negative/positive). We provide the physical explanation on the polarity of observed bipolar EFS structures with an electrostatic ion fluid model. The results show that ii initial electric field E0 > 0, the polarity of the bipolar EFS structure will be positive/negative; and if E0 < 0, the polarity of the bipolar EFS structure will be negative/positive. However, for a fixed polarity of the EFS, either positive/negative or negative/positive, if the satellite is located at the positive side of the EFS, the observed polarity should be positive/negative, if the satellite is located at the negative side of the EFS, the observed polarity should be negative/positive. Therefore, we provide a method to clarify the natural polarity of the EFS with observed polarity by satellites. Our results are significant to understand the physical process in space plasma with the satellite observation.%@@ The bipolar electric field solitary (EFS) structures observed frequently in space plasmas by satellites have two different polarities, first positive electric Held peak then negative (i.e., positive/negative) and first negative then positive peak (i.e., negative/positive).We provide the physical explanation on the polarity of observed bipolar EFS structures with an electrostatic ion fluid model.

  13. Space-Time Localization of Inner Heliospheric Plasma Turbulence Using Multiple Spacecraft Radio Links

    CERN Document Server

    Richie-Halford, Adam C; Tortora, Paolo; Armstrong, John W; Asmar, Sami W; Woo, Richard; Habbal, Shadia Rifai; Morgan, Huw; 10.1029/2009SW000499

    2010-01-01

    Radio remote sensing of the heliosphere using spacecraft radio signals has been used to study the near-sun plasma in and out of the ecliptic, close to the sun, and on spatial and temporal scales not accessible with other techniques. Studies of space-time variations in the inner solar wind are particularly timely because of the desire to understand and predict space weather, which can disturb satellites and systems at 1AU and affect human space exploration. Here we demonstrate proof-of-concept of a new radio science application for spacecraft radio science links. The differing transfer functions of plasma irregularities to spacecraft radio up- and downlinks can be exploited to localize plasma scattering along the line of sight. We demonstrate the utility of this idea using Cassini radio data taken in 2001-2002. Under favorable circumstances we demonstrate how this technique, unlike other remote sensing methods, can determine center-of-scattering position to within a few thousandths of an AU and thickness of sc...

  14. Kinetic Space Weather: Toward a Global Hybrid Model of the Polar Ionosphere-Lower Magnetosphere Plasma Transport

    Science.gov (United States)

    Horwitz, James L.

    1996-01-01

    During the indicated period of performance, we had a number of publications concerned with kinetic polar ionosphere-lower magnetosphere plasma transport. For the IUGG 1991-4 Quadrennial Report, we reviewed aspects of U.S. accomplishments concerned with polar plasma transport, among other issues. In another review, we examined the computer simulations of multiple-scale processes in space plasmas, including polar plasma outflow and transport. We also examined specifically multiscale processes in ionospheric outflows. We developed a Generalized Semi-Kinetic(GSK) model for the topside-lower magnetosphere which explored the synergistic action of wave heating and electric potentials in the formation of auroral Ion conics, in particular the "pressure cooker" mechanism. We extended the GSK model all the way down to 120 km and applied this code to illustrate the response of the ionosphere- magnetosphere to soft-electron precipitation and convection-driven frictional ion heating, respectively. Later, the convection-driven heating work was extended to a paper for the Journal of Geophysical Research. In addition to the above full published papers, we also presented the first developments of the coupled fluid-semikinetic model for polar plasma transport during this period. The results from a steady-state treatment were presented, with the second presentation being concerned with the effects of photo-electrons on the polar wind, and the first garnering an outstanding student paper award from the American Geophysical Union. We presented the first results from a time-dependent version of this coupled fluid-semikinetic model.

  15. Generation and detection of whistler wave induced space plasma turbulence at Gakona, Alaska

    Science.gov (United States)

    Rooker, L. A.; Lee, M. C.; Pradipta, R.; Watkins, B. J.

    2013-07-01

    We report on high-frequency wave injection experiments using the beat wave technique to study the generation of very-low-frequency (VLF) whistler waves in the ionosphere above Gakona, Alaska. This work is aimed at investigating whistler wave interactions with ionospheric plasmas and radiation belts. The beat wave technique involves injecting two X-mode waves at a difference frequency in the VLF range using the High-frequency Active Auroral Research Program (HAARP) heating facility. A sequence of beat wave-generated whistler waves at 2, 6.5, 7.5, 8.5, 9.5, 11.5, 15.5, 22.5, 28.5 and 40.5 kHz were detected in our 2011 experiments. We present Modular Ultra-high-frequency Ionospheric Radar (MUIR) (446 MHz) measurements of ion lines as the primary diagnosis of ionospheric plasma effects caused by beat wave-generated whistler waves. A magnetometer and digisonde were used to monitor the background ionospheric plasma conditions throughout the experiments. Our theoretical and data analyses show that VLF whistler waves can effectively interact with ionospheric plasmas via two different four-wave interaction processes leading to energization of electrons and ions. These preliminary results support our Arecibo experiments to study NAU-launched 40.75 kHz whistler wave interactions with space plasmas.

  16. Potential high efficiency solar cells: Applications from space photovoltaic research

    Science.gov (United States)

    Flood, D. J.

    1986-01-01

    NASA involvement in photovoltaic energy conversion research development and applications spans over two decades of continuous progress. Solar cell research and development programs conducted by the Lewis Research Center's Photovoltaic Branch have produced a sound technology base not only for the space program, but for terrestrial applications as well. The fundamental goals which have guided the NASA photovoltaic program are to improve the efficiency and lifetime, and to reduce the mass and cost of photovoltaic energy conversion devices and arrays for use in space. The major efforts in the current Lewis program are on high efficiency, single crystal GaAs planar and concentrator cells, radiation hard InP cells, and superlattice solar cells. A brief historical perspective of accomplishments in high efficiency space solar cells will be given, and current work in all of the above categories will be described. The applicability of space cell research and technology to terrestrial photovoltaics will be discussed.

  17. Dust in the planetary system: Dust interactions in space plasmas of the solar system

    Science.gov (United States)

    Mann, Ingrid; Meyer-Vernet, Nicole; Czechowski, Andrzej

    2014-03-01

    Cosmic dust particles are small solid objects observed in the solar planetary system and in many astronomical objects like the surrounding of stars, the interstellar and even the intergalactic medium. In the solar system the dust is best observed and most often found within the region of the orbits of terrestrial planets where the dust interactions and dynamics are observed directly from spacecraft. Dust is observed in space near Earth and also enters the atmosphere of the Earth where it takes part in physical and chemical processes. Hence space offers a laboratory to study dust-plasma interactions and dust dynamics. A recent example is the observation of nanodust of sizes smaller than 10 nm. We outline the theoretical considerations on which our knowledge of dust electric charges in space plasmas are founded. We discuss the dynamics of the dust particles and show how the small charged particles are accelerated by the solar wind that carries a magnetic field. Finally, as examples for the space observation of cosmic dust interactions, we describe the first detection of fast nanodust in the solar wind near Earth orbit and the first bi-static observations of PMSE, the radar echoes that are observed in the Earth ionosphere in the presence of charged dust.

  18. Extension of the coherence function to quadratic models. [applied to plasma density and potential fluctuations

    Science.gov (United States)

    Kim, Y. C.; Wong, W. F.; Powers, E. J.; Roth, J. R.

    1979-01-01

    It is shown how the use of higher coherence functions can recover some of the lost coherence due to nonlinear relationship between two fluctuating quantities whose degree of mutual coherence is being measured. The relationship between the two processes is modeled with the aid of a linear term and a quadratic term. As a specific example, the relationship between plasma density and potential fluctuations in a plasma is considered. The fraction of power in the auto-power spectrum of the potential fluctuations due to a linear relationship and to a quadratic relationship between the density and potential fluctuations is estimated.

  19. Estimate of electrical potential difference between plasmas with different degrees of ionization

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Chong [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-01-12

    The electrical potential difference has been estimated across the mixing region of two plasmas with different degrees of ionization. The estimation has been carried out in two different contexts of a charge neutral mixing region and a charge non-neutral sheath. Ion energy gained due to the potential difference has also been estimated. In both analyses, ion energy gain is proportional to the degree of ionization, and a fairly large ionization appears to be needed for overcoming the potential energy barrier of strongly coupled plasmas.

  20. Ionization-potential depression and dynamical structure factor in dense plasmas

    Science.gov (United States)

    Lin, Chengliang; Röpke, Gerd; Kraeft, Wolf-Dietrich; Reinholz, Heidi

    2017-07-01

    The properties of a bound electron system immersed in a plasma environment are strongly modified by the surrounding plasma. The modification of an essential quantity, the ionization energy, is described by the electronic and ionic self-energies, including dynamical screening within the framework of the quantum statistical theory. Introducing the ionic dynamical structure factor as the indicator for the ionic microfield, we demonstrate that ionic correlations and fluctuations play a critical role in determining the ionization potential depression. This is, in particular, true for mixtures of different ions with large mass and charge asymmetry. The ionization potential depression is calculated for dense aluminum plasmas as well as for a CH plasma and compared to the experimental data and more phenomenological approaches used so far.

  1. Normal chemotaxis in Dictyostelium discoideum cells with a depolarized plasma membrane potential

    NARCIS (Netherlands)

    Duijn, Bert van; Vogelzang, Sake A.; Ypey, Dirk L.; Molen, Loek G. van der; Haastert, Peter J.M. van

    1990-01-01

    We examined a possible role for the plasma membrane potential in signal transduction during cyclic AMP-induced chemotaxis in the cellular slime mold Dictyostelium discoideum. Chemotaxis, cyclic GMP and cyclic AMP responses in cells with a depolarized membrane potential were measured. Cells can be

  2. Internal oscillating current-sustained RF plasmas: Parameters, stability, and potential for surface engineering

    DEFF Research Database (Denmark)

    Ostrikov, K.; Tsakadze, E.L.; Tsakadze, Z.L.;

    2005-01-01

    plasma parameters by the optical and Langmuir probes are presented. It is shown that the spatial profiles of the electron density, the effective electron temperature and plasma potential feature a great deal of the radial and axial uniformity compared with conventional sources of inductively coupled......A new source of low-frequency (0.46 MHz) inductively coupled plasmas sustained by the internal planar "unidirectional" RF current driven through a specially designed internal antenna configuration has been developed. The experimental results of the investigation of the optical and global argon...... applications and surface engineering. (c) 2005 Elsevier B.V. All rights reserved....

  3. Kinetic theory of twisted waves: Application to space plasmas having superthermal population of species

    Science.gov (United States)

    Arshad, Kashif; Poedts, Stefaan; Lazar, Marian

    2017-04-01

    ring shape morphology of a beam with orbital angular momentum (OAM) is ideal for the observation of solar corona around the sun where the intensity of the beam is minimum at the center, in solar experiments, and Earth's ionosphere. The twisted plasma modes carrying OAM are mostly studied either by the fluid theory or Maxwellian distributed Kinetic Theory. But most of the space plasmas and some laboratory plasmas have non-thermal distributions due to super-thermal population of the plasma particles. Therefore the Kinetic Theory of twisted plasma modes carrying OAM are recently studied using non-thermal (kappa) distribution of the super-thermal particles in the presence of the helical electric field and significant change in the damping rates are observed by tuning appropriate parameters.

  4. Irregularities Associated with Artificially Created Dusty Plasmas in the near Earth Space Environment

    Science.gov (United States)

    Bordikar, M. R.; Scales, W.; Mahmoudian, A.; Fu, H.

    2009-12-01

    A natural dust layer formed by tons of meteoric dust spans the altitude range between 80 and 100 kilometers of the earth’s upper mesosphere and lower thermosphere which forms Noctilucent Clouds NLCs. These dust layers are charged due to collection of electrons and ions from the earth’s ionosphere. Polar Mesospheric Summer Echoes are radar echoes which result from scattering from the irregularities in the electron density above the NLC altitude. An alternate approach to understanding natural dust layers is to perform active space experiments in which a dust cloud is artificially created in a controlled manner in the upper atmosphere. The goal of Charged Aerosol Release Experiment (CARE) is to investigate similarity in plasma irregularity associated with natural and artificial dust layers. This presentation will address some of the physical processes expected to be important during the early time phase after creation of an artificial dust cloud in the earth’s ionosphere. Of major importance will be the production of plasma irregularities which may lead to radar echoes and the possibility of their relationship to PMSEs observed from natural dusty space plasmas. The objective is to investigate the production of electron irregularities due to growth of plasma instabilities driven by inhomogeneities in the boundary between the background plasma and the expanding charged dust layer. First, a two dimensional plasma simulation model will be described that may be used for examining early time evolution after expansion of an artificial dust cloud across the magnetic field in the ionosphere. The model considers a three species system with fluid electrons and ions and Particle-In-Cell PIC charged dust grains in which the dust charge on the grains varies in time according to the standard charging model. The electrons are magnetized and the algorithm incorporates the parallel electron dynamics while the ions are assumed to be unmagnetized. Simulations runs were made to

  5. Arbitrary amplitude slow electron-acoustic solitons in three-electron temperature space plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Mbuli, L. N. [South African National Space Agency (SANSA) Space Science, P.O. Box 32, Hermanus 7200, Republic of South Africa (South Africa); University of the Western Cape, Robert Sobukwe Road, Bellville 7535, Republic of South Africa (South Africa); Maharaj, S. K. [South African National Space Agency (SANSA) Space Science, P.O. Box 32, Hermanus 7200, Republic of South Africa (South Africa); Bharuthram, R. [University of the Western Cape, Robert Sobukwe Road, Bellville 7535, Republic of South Africa (South Africa); Singh, S. V.; Lakhina, G. S. [Indian Institute of Geomagnetism, New Panvel (West), Navi Mumbai 410218 (India)

    2015-06-15

    We examine the characteristics of large amplitude slow electron-acoustic solitons supported in a four-component unmagnetised plasma composed of cool, warm, hot electrons, and cool ions. The inertia and pressure for all the species in this plasma system are retained by assuming that they are adiabatic fluids. Our findings reveal that both positive and negative potential slow electron-acoustic solitons are supported in the four-component plasma system. The polarity switch of the slow electron-acoustic solitons is determined by the number densities of the cool and warm electrons. Negative potential solitons, which are limited by the cool and warm electron number densities becoming unreal and the occurrence of negative potential double layers, are found for low values of the cool electron density, while the positive potential solitons occurring for large values of the cool electron density are only limited by positive potential double layers. Both the lower and upper Mach numbers for the slow electron-acoustic solitons are computed and discussed.

  6. Easy measurement of diffusion coefficients of EGFP-tagged plasma membrane proteins using k-space Image Correlation Spectroscopy

    DEFF Research Database (Denmark)

    Christensen, Eva Arnspang; Koffman, Jennifer Skaarup; Marlar, Saw

    2014-01-01

    Lateral diffusion and compartmentalization of plasma membrane proteins are tightly regulated in cells and thus, studying these processes will reveal new insights to plasma membrane protein function and regulation. Recently, k-Space Image Correlation Spectroscopy (kICS)1 was developed to enable ro...

  7. Development and Potential of Space-Borne Doppler Wind Lidar

    Institute of Scientific and Technical Information of China (English)

    LIU Zhishen; SUN Dapeng; WU Dong; Juergen Streicher; Ines Leike

    2003-01-01

    The advantage of lidar over other wind sensors is presented in this paper. With more than 20 years research, the development of the space-borne wind lidar is reviewed. Longer-term investigation has made many technologies suitable for the wind lidar measurement from an orbital platform become mature. However, there are still some problems to be solved. In order to obtain the optimal performance in wind detection, great importance is being attached to the simulation of a virtual space-borne wind lidar system on computer as developed by NASA and ESA.

  8. Phase-Space Position-Momentum Correlation and Potentials

    Directory of Open Access Journals (Sweden)

    Robin P. Sagar

    2013-04-01

    Full Text Available Solutions to the radial Schr¨odinger equation of a particle in a quantum corral are used to probe how the statistical correlation between the position, and The momentum of the particle depends on the effective potential. The analysis is done via the Wigner function and its Shannon entropy. We show by comparison to the particle-in-a-box model that the attractive potential increases the magnitude of the correlation, while a repulsive potential decreases the magnitude of this correlation. Varying the magnitude of the repulsive potential yields that the correlation decreases with a stronger repulsive potential.

  9. Velocity-space tomography of fusion plasmas by collective Thomson scattering of gyrotron radiation

    DEFF Research Database (Denmark)

    Salewski, Mirko; Jacobsen, A.S.; Jensen, Thomas;

    2016-01-01

    We propose a diagnostic capable of measuring 2D fast-ion velocity distribution functions 푓2퐷푣 in the MeV-range in magnetized fusion plasmas. Today velocity-space tomography based on fast-ion D훼 spectroscopy is regularly used to measure 푓2퐷푣 for ion energies below 100 keV. Unfortunately, the signal......-tonoise ratio becomes fairly low for MeV-range ions. Ions at any energy can be detected well by collective Thomson scattering of mm-wave radiation from a high-power gyrotron. We demonstrate how collective Thomson scattering can be used to measure 푓2퐷푣 in the MeV-range in reactor relevant plasmas...

  10. Magnetic turbulence in space plasmas: in and around the Earth's magnetosphere

    Energy Technology Data Exchange (ETDEWEB)

    Zimbardo, Gaetano [Universita della Calabria, Dipartimento di Fisica, Ponte P. Bucci, Cubo 31C, I-87036 Arcavacata di Rende (Italy)

    2006-12-15

    In collisionless space plasmas most phenomena are governed by wave particle interaction and by the interaction with the large scale fields. Low frequency magnetic turbulence in the solar wind is relatively well characterized and understood. The situation is more complicated for magnetic turbulence in and around the Earth's magnetosphere, where the turbulence feature can vary widely with the location. Recent spacecraft observations of magnetic turbulence in the magnetosheath, in the polar cusp regions and in the magnetotail are considered. Turbulence features like the fluctuation level, the spectral power law index, the turbulence drivers and the turbulence anisotropy and intermittency are addressed. The influence of such a turbulence on the plasma transport and dynamics is briefly described, also using the results of numerical simulations.

  11. Plasma and urine catecholamine levels in cosmonauts during long-term stay on Space Station Salyut-7

    Science.gov (United States)

    Kvetn̆anský, R.; Davydova, N. A.; Noskov, V. B.; Vigas̆, M.; Popova, I. A.; Us̆akov, A. C.; Macho, L.; Grigoriev, A. I.

    The activity of the sympathetic adrenal system in cosmonauts exposed to a stay in space lasting for about half a year has so far been studied only by measuring catecholamine levels in plasma and urine samples taken before space flight and after landing. The device "Plasma 01", specially designed for collecting and processing venous blood from subjects during space flight on board the station Salyut-7 rendered it possible for the first time to collect and freeze samples of blood from cosmonauts in the course of a long-term 237-day space flight. A physician-cosmonaut collected samples of blood and urine from two cosmonauts over the period of days 217-219 of their stay in space. The samples were transported to Earth frozen. As indicators of the sympathetic adrenal system activity, plasma and urine concentrations of epinephrine and norepinephrine as well as urine levels of the catecholamine metabolites metanephrine, normetanephrine, and vanillylmandelic acid were determined before, during and after space flight. On days 217-219 of space flight plasma epinephrine and norepinephrine levels were slightly increased, yet not substantially different from normal. During stress situations plasma norepinephrine and epinephrine levels usually exhibit a manifold increase. On days 217-219 of space flight norepinephrine and epinephrine levels in urine were comparable with pre-flight values and the levels of their metabolites were even significantly decreased. All the parameters studied, particularly plasma norepinephrine as well as urine norepinephrine, normetanephrine, and vanillylmandelic acid, reached the highest values 8 days after landing. The results obtained suggest that, in the period of days 217-219 of the cosmonauts' stay in space in the state of weightlessness, the sympathetic adrenal system is either not activated at all or there is but a slight activation induced by specific activities of the cosmonauts, whereas in the process of re-adaptation after space flight on

  12. Membrane potential governs lateral segregation of plasma membrane proteins and lipids in yeast.

    Science.gov (United States)

    Grossmann, Guido; Opekarová, Miroslava; Malinsky, Jan; Weig-Meckl, Ina; Tanner, Widmar

    2007-01-10

    The plasma membrane potential is mainly considered as the driving force for ion and nutrient translocation. Using the yeast Saccharomyces cerevisiae as a model organism, we have discovered a novel role of the membrane potential in the organization of the plasma membrane. Within the yeast plasma membrane, two non-overlapping sub-compartments can be visualized. The first one, represented by a network-like structure, is occupied by the proton ATPase, Pma1, and the second one, forming 300-nm patches, houses a number of proton symporters (Can1, Fur4, Tat2 and HUP1) and Sur7, a component of the recently described eisosomes. Evidence is presented that sterols, the main lipid constituent of the plasma membrane, also accumulate within the patchy compartment. It is documented that this compartmentation is highly dependent on the energization of the membrane. Plasma membrane depolarization causes reversible dispersion of the H(+)-symporters, not however of the Sur7 protein. Mitochondrial mutants, affected in plasma membrane energization, show a significantly lower degree of membrane protein segregation. In accordance with these observations, depolarized membranes also considerably change their physical properties (detergent sensitivity).

  13. Plasma-modified and polyethylene glycol-grafted polymers for potential tissue engineering applications.

    Science.gov (United States)

    Svorcík, V; Makajová, Z; Kasálková-Slepicková, N; Kolská, Z; Bacáková, L

    2012-08-01

    Modified and grafted polymers may serve as building blocks for creating artificial bioinspired nanostructured surfaces for tissue engineering. Polyethylene (PE) and polystyrene (PS) were modified by Ar plasma and the surface of the plasma activated polymers was grafted with polyethylene glycol (PEG). The changes in the surface wettability (contact angle) of the modified polymers were examined by goniometry. Atomic Force Microscopy (AFM) was used to determine the surface roughness and morphology and electrokinetical analysis (Zeta potential) characterized surface chemistry of the modified polymers. Plasma treatment and subsequent PEG grafting lead to dramatic changes in the polymer surface morphology, roughness and wettability. The plasma treated and PEG grafted polymers were seeded with rat vascular smooth muscle cells (VSMCs) and their adhesion and proliferation were studied. Biological tests, performed in vitro, show increased adhesion and proliferation of cells on modified polymers. Grafting with PEG increases cell proliferation, especially on PS. The cell proliferation was shown to be an increasing function of PEG molecular weight.

  14. Tardigrades as a Potential Model Organism in Space Research

    Science.gov (United States)

    Jönsson, K. Ingemar

    2007-10-01

    Exposure of living organisms to open space requires a high level of tolerance to desiccation, cold, and radiation. Among animals, only anhydrobiotic species can fulfill these requirements. The invertebrate phylum Tardigrada includes many anhydrobiotic species, which are adapted to survive in very dry or cold environmental conditions. As a likely by-product of the adaptations for desiccation and freezing, tardigrades also show a very high tolerance to a number of other, unnatural conditions, including exposure to ionizing radiation. This makes tardigrades an interesting candidate for experimental exposure to open space. This paper reviews the tolerances that make tardigrades suitable for astrobiological studies and the reported radiation tolerance in other anhydrobiotic animals. Several studies have shown that tardigrades can survive γ-irradiation well above 1 kilogray, and desiccated and hydrated (active) tardigrades respond similarly to irradiation. Thus, tolerance is not restricted to the dry anhydrobiotic state, and I discuss the possible involvement of an efficient, but yet undocumented, mechanism for DNA repair. Other anhydrobiotic animals (Artemia, Polypedium), when dessicated, show a higher tolerance to γ-irradiation than hydrated animals, possibly due to the presence of high levels of the protective disaccharide trehalose in the dry state. Tardigrades and other anhydrobiotic animals provide a unique opportunity to study the effects of space exposure on metabolically inactive but vital metazoans.

  15. Magnetic reconnection in turbulent space plasmas: null-points or pinches?

    Science.gov (United States)

    Olshevsky, Vyacheslav; Lapenta, Giovanni; Markidis, Stefano; Divin, Andrey

    2014-05-01

    We report particle-in-cell simulations of magnetic reconnection in the configuration containing both null-points and pinches. All indicators suggest that secondary magnetic reconnection driven by kinking of the pinches plays a dominant role in the energetics of the system. While there is no substantial energy dissipation in the vicinity of X-type null-points. Such reconnection results in tremendous release of magnetic energy, generation of suprathermal particles and waves. Similar scenario may take place in turbulent space plasmas, where current channels and twisted magnetic fields are detected.

  16. Theory and Observations of Plasma Waves Excited Space Shuttle OMS Burns in the Ionosphere

    Science.gov (United States)

    Bernhardt, P. A.; Pfaff, R. F.; Schuck, P. W.; Hunton, D. E.; Hairston, M. R.

    2010-12-01

    Measurements of artificial plasma turbulence were obtained during two Shuttle Exhaust Ionospheric Turbulence Experiments (SEITE) conducted during the flights of the Space Shuttle (STS-127 and STS-129). Based on computer modeling at the NRL PPD and Laboratory for Computational Physics & Fluid Dynamics (LCP), two dedicated burns of the Space Shuttle Orbital Maneuver Subsystem (OMS) engines were scheduled to produce 200 to 240 kg exhaust clouds that passed over the Air Force Research Laboratory (AFRL) Communications, Navigation, and Outage Forecast System (C/NOFS) satellite. This operation required the coordination by the DoD Space Test Program (STP), the NASA Flight Dynamics Officer (FDO), the C/NOFS payload operations, and the C/NOFS instrument principal investigators. The first SEITE mission used exhaust from a 12 Second OMS burn to deposit 1 Giga-Joules of energy into the upper atmosphere at a range of 230 km from C/NOFS. The burn was timed so C/NOFS could fly though the center of the exhaust cloud at a range of 87 km above the orbit of the Space Shuttle. The first SEITE experiment is important because is provided plume detection by ionospheric plasma and electric field probes for direct sampling of irregularities that can scatter radar signals. Three types of waves were detected by C/NOFS during and after the first SEITE burn. With the ignition and termination of the pair of OMS engines, whistler mode signals were recorded at C/NOFS. Six seconds after ignition, a large amplitude electromagnetic pulse reached the satellite. This has been identified as a fast magnetosonic wave propagating across magnetic field lines to reach the electric field (VEFI) sensors on the satellite. Thirty seconds after the burn, the exhaust cloud reach C/NOFS and engulfed the satellite providing very strong electric field turbulence along with enhancements in electron and ion densities. Kinetic modeling has been used to track the electric field turbulence to an unstable velocity

  17. On the relation between QCD potentials in momentum and position space

    OpenAIRE

    Jezabek, M.; Peter, M.; Sumino, Y.

    1998-01-01

    We derive a formula which relates the QCD potentials in momentum space and in position space in terms of the beta-function of the renormalization-group equation for the potential. This formula is used to study the theoretical uncertainties in the potential and in particular in its application to the determination of the pole mass m_b when we use perturbative expansions. We demonstrate the existence of these uncertainties for the Richardson potential explicitly and then discuss the limited the...

  18. Potential cellular targets and antibacterial efficacy of atmospheric pressure non-thermal plasma.

    Science.gov (United States)

    Alkawareek, Mahmoud Y; Gorman, Sean P; Graham, William G; Gilmore, Brendan F

    2014-02-01

    Atmospheric pressure non-thermal plasma (APNTP) has been gaining increasing interest as a new alternative antibacterial approach. Although this approach has demonstrated promising antibacterial activity, its exact mechanism of action remains unclear. Mechanistic elucidation of the antimicrobial activity will facilitate development and rational optimisation of this approach for potential medical applications. In this study, the antibacterial efficacy of an in-house-built APNTP jet was evaluated alongside an investigation of the interactions between APNTP and major cellular components in order to identify the potential cellular targets involved in plasma-mediated bacterial destruction mechanisms. The investigated plasma jet exhibited excellent, rapid antibacterial activity against a selected panel of clinically significant bacterial species including Bacillus cereus, meticillin-resistant Staphylococcus aureus (MRSA), Escherichia coli and Pseudomonas aeruginosa, all of which were completely inactivated within 2 min of plasma exposure. Plasma-mediated damaging effects were observed, to varying degrees, on all of the investigated cellular components including DNA, a model protein enzyme, and lipid membrane integrity and permeability. The antibacterial efficacy of APNTP appears to involve a multiple-target mechanism, which potentially reduces the likelihood of emergence of microbial resistance towards this promising antimicrobial approach. However, cellular membrane damage and resulting permeability perturbation was found to be the most likely rate-determining step in this mechanism.

  19. Double Potential Pulse Chronocoulometry for Detection of Plasma Membrane Cholesterol Efflux at Disk Platinum Microelectrodes

    Science.gov (United States)

    West, Richard H.; Lu, Hui; Shaw, Kendrick; Chiel, Hillel J.; Kelley, Thomas J.; Burgess, James D.

    2016-01-01

    A double potential pulse scheme is reported for observation of cholesterol efflux from the plasma membrane of a single neuron cell. Capillary Pt disk microelectrodes having a thin glass insulator allow the 10 μm diameter electrode and cell to be viewed under optical magnification. The electrode, covalently functionalized with cholesterol oxidase, is positioned in contact with the cell surface resulting in enzyme catalyzed cholesterol oxidation and efflux of cholesterol from the plasma membrane at the electrode contact site. Enzymatically generated hydrogen peroxide accumulates at the electrode/cell interface during a 5 s hold-time and is oxidized during application of a potential pulse. A second, replicate potential pulse is applied 0.5 s after the first potential pulse to gauge background charge prior to significant accumulation of hydrogen peroxide. The difference in charge passed between the first and second potential pulse provides a measure of hydrogen peroxide generated by the enzyme and is an indication of the cholesterol efflux. Control experiments for bare Pt microelectrodes in contact with the cell plasma membrane show difference charge signals in the range of about 7–10 pC. Enzyme-modified electrodes in contact with the plasma membrane show signals in the range of 16–26 pC. PMID:27330196

  20. Preliminary feasibility study of pallet-only mode for magnetospheric and plasmas in space payloads, volume 4

    Science.gov (United States)

    1976-01-01

    Results of studies performed on the magnetospheric and plasma portion of the AMPS are presented. Magnetospheric and plasma in space experiments and instruments are described along with packaging (palletization) concepts. The described magnetospheric and plasma experiments were considered as separate entities. Instrumentation ospheric and plasma experiments were considered as separate entities. Instrumentation requirements and operations were formulated to provide sufficient data for unambiguous interpretation of results without relying upon other experiments of the series. Where ground observations are specified, an assumption was made that large-scale additions or modifications to existing facilities were not required.

  1. Recent progress on phase-space turbulence and dynamical response in collisionless plasmas

    CERN Document Server

    Lesur, Maxime

    2013-01-01

    In the presence of wave dissipation, phase-space structures emerge in nonlinear Vlasov dynamics. Their dynamics can lead to a nonlinear continuous shifting of the wave frequency (chirping). This report summarizes my personal contribution to these topics in the fiscal year 2012. The effects of collisions on chirping characteristics were investigated, with a one-dimensional beam-plasma kinetic model. The long-time nonlinear evolution was systematically categorized as damped, steady-state, periodic, chaotic and chirping. The chirping regime was sub-categorized as periodic, chaotic, bursty, and intermittent. Existing analytic theory was extended to account for Krook-like collisions. Relaxation oscillations, associated with chirping bursts, were investigated in the presence of dynamical friction and velocity-diffusion. The period increases with decreasing drag, and weakly increases with decreasing diffusion. A new theory gives a simple relation between the growth of phase-space structures and that of the wave ener...

  2. Gyrokinetic simulations of fusion plasmas using a spectral velocity space representation

    CERN Document Server

    Parker, Joseph Thomas

    2016-01-01

    Magnetic confinement fusion reactors suffer severely from heat and particle losses through turbulent transport, which has inspired the construction of ever larger and more expensive reactors. Numerical simulations are vital to their design and operation, but particle collisions are too infrequent for fluid descriptions to be valid. Instead, strongly magnetised fusion plasmas are described by the gyrokinetic equations, a nonlinear integro-differential system for evolving the particle distribution functions in a five-dimensional position and velocity space, and the consequent electromagnetic field. Due to the high dimensionality, simulations of small reactor sections require hundreds of thousands of CPU hours on High Performance Computing platforms. We develop a Hankel-Hermite spectral representation for velocity space that exploits structural features of the gyrokinetic system. The representation exactly conserves discrete free energy in the absence of explicit dissipation, while our Hermite hypercollision ope...

  3. Cluster spacecraft observations of a ULF wave enhanced by Space Plasma Exploration by Active Radar (SPEAR

    Directory of Open Access Journals (Sweden)

    S. V. Badman

    2009-09-01

    Full Text Available Space Plasma Exploration by Active Radar (SPEAR is a high-latitude ionospheric heating facility capable of exciting ULF waves on local magnetic field lines. We examine an interval from 1 February 2006 when SPEAR was transmitting a 1 Hz modulation signal with a 10 min on-off cycle. Ground magnetometer data indicated that SPEAR modulated currents in the local ionosphere at 1 Hz, and enhanced a natural field line resonance with a 10 min period. During this interval the Cluster spacecraft passed over the heater site. Signatures of the SPEAR-enhanced field line resonance were present in the magnetic field data measured by the magnetometer on-board Cluster-2. These are the first joint ground- and space-based detections of field line tagging by SPEAR.

  4. Electric Propulsion Test & Evaluation Methodologies for Plasma in the Environments of Space and Testing (EP TEMPEST) (Briefing Charts)

    Science.gov (United States)

    2015-04-01

    transitioned to FalconSat-6, NASA, industry, and academia • Correlated thruster plasma oscillations with transient ion flux impacting chamber...Research PAYOFF - Pervasive Space Capability for Increased Payload Transition Improved T&E Methods Cannot fully replicate space environment in ground

  5. Momentum-space optical potential SND elastic scattering calculations

    Energy Technology Data Exchange (ETDEWEB)

    Wolfe, D.H.; Hynes, M.V.; Picklesimer, A.; Tandy, P.C.; Thaler, R.M.

    1983-01-01

    Initial results are presented for proton-nucleus elastic scattering observables calculated with a newly developed microscopic momentum-space code. This is the first phase of a program to treat elastic and inelastic scattering consistently via an integral equation approach. A number of microscopic features which are often approximated or ignored are quite amenable to exact treatment within this approach, e.g. non-local effects in elastic scattering, and inelastic effects which are non-linear in the NN t-matrix and target densities but nevertheless confined to one participating nucleon. 3 references.

  6. Momentum-space optical potential SND elastic scattering calculations

    Science.gov (United States)

    Wolfe, D. H.; Hynes, M. V.; Picklesimer, A.; Tandy, P. C.; Thaler, R. M.

    1983-03-01

    Initial results are presented for proton-nucleus elastic scattering observables calculated with a newly developed microscopic momentum-space code. This is the first phase of a program to treat elastic and inelastic scatterig consistently via an integral equation approach. A number of microscopic features which are often approximated or ignored are quite amenable to exact treatment within this approach, e.g. non-local effectss in elastic scattering, and inelastic effects which are non-linear in the NN t-matrix and target densities but nevertheless confined to one participating nucleon.

  7. Radiological risk analysis of potential SP-100 space mission scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Bartram, B.W.; Weitzberg, A.

    1988-08-19

    This report presents a radiological risk analysis of three representative space mission scenarios utilizing a fission reactor. The mission profiles considered are: a high-altitude mission, launched by a TITAN IV launch vehicle, boosted by chemical upper stages into its operational orbit, a interplanetary nuclear electric propulsion (NEP) mission, started directly from a shuttle parking orbit, a low-altitude mission, launched by the Shuttle and boosted by a chemical stage to its operational orbit, with subsequent disposal boost after operation. 21 refs., 12 figs., 7 tabs.

  8. Formation of Non-Monotonic Potential Structure in the Detached Plasma

    Science.gov (United States)

    Ishiguro, Seiji; Pianpanit, Theerasarn; Hasegawa, Hiroki

    2016-10-01

    Plasma detachment has been investigated by means of PIC simulation which includes plasma-neutral collision and Coulomb collision. In our previous study, we have shown that a strong gradient in temperature appears in front of the target plate in the case that high density and low temperature neutral gas is introduced. It is observed that a potential hill is created in the neutral gas region where ions lose energy due to the elastic and charge exchange collision and, as a result, the ion density increases. This potential structure traps the low energy electrons and may play a role in the development of plasma detachment state. This work is supported by NIFS Collaboration Research Programs NIFS14KNXN279 and NIFS14KNSS059 and the NIFS/NINS project of Formation of International Scientific Base and Network.

  9. Potential Industrial Applications of the One Atmosphere Uniform Glow Discharge Plasma (OAUGDP) Operating in Ambient Air

    Science.gov (United States)

    Reece Roth, J.

    2004-11-01

    The majority of industrial plasma processing with glow discharges has been conducted at pressures below 10 torr. This tends to limit applications to high value workpieces as a result of the high capital cost of vacuum systems and the production constraints of batch processing. It has long been recognized that glow discharge plasmas would play a much larger industrial role if they could be generated at one atmosphere. The One Atmosphere Uniform Glow Discharge Plasma (OAUGDP), developed at the University of Tennessee's Plasma Sciences Laboratory, is a non-thermal RF plasma operating on displacement currents with the time-resolved characteristics of a classical low pressure DC normal glow discharge. As a glow discharge, the OAUGDP operates with maximum electrical efficiency at the Stoletow point, where the energy input per ion-electron pair is a minimum [1, 2]. Several interdisciplinary teams have investigated potential applications of the OAUGDP. These teams included collaborators from the UTK Textiles and Nonwovens Development Center (TANDEC), and the Departments of Electrical and Computer Engineering, Microbiology, and Food Science and Technology, as well as the NASA Langley Research Center. The potential applications of the OAUGDP have all been at one atmosphere and room temperature, using air as the working gas. These applications include sterilizing medical and dental equipment; sterilizable air filters to deal with the "sick building syndrome"; removal of soot from Diesel engine exhaust; subsonic plasma aerodynamic effects, including flow re-attachment to airfoils and boundary layer modification; electrohydrodynamic (EDH) flow control of working gases; increasing the surface energy of materials; improving the adhesion of paints and electroplated layers: improving the wettability and wickability of fabrics; stripping of photoresist; and plasma deposition and directional etching of potential microelectronic relevance. [1] J. R. Roth, Industrial Plasma Engineering

  10. Debris Engine: A Potential Thruster for Space Debris Removal

    CERN Document Server

    Lan, Lei; Baoyin, Hexi

    2015-01-01

    We present a design concept for a space engine that can continuously remove the orbit debris by using the debris as a propellant. Space robotic cleaner is adopted to capture the targeting debris and to transfer them into the engine. Debris with larger size is first disintegrated into small pieces by using a mechanical method. The planetary ball mill is then adopted to grind the pieces into micrometer or smaller powder. The energy needed in this process is get from the nuclear and solar power. By the effect of gamma-ray photoelectric or the behavior of tangently rub of tungsten needles, the debris powered is charged. This behavior can be used to speed up the movement of powder in a tandem electrostatic particle accelerator. By ejecting the high-temperture and high-pressure charged powered from the nozzle of the engine,the continuously thrust is obtained. This thrust can be used to perform orbital maneuver and debris rendezvous for the spacecraft and robotic cleaner. The ejected charged particle will be blown a...

  11. Physical simulation of the long-term dynamic action of a plasma beam on a space debris object

    Science.gov (United States)

    Shuvalov, Valentin A.; Gorev, Nikolai. B.; Tokmak, Nikolai A.; Kochubei, Galina S.

    2017-03-01

    A methodology is developed for physical (laboratory) simulation of the long-term dynamic action of plasma beam high-energy ions on a space debris object with the aim of removing it to a lower orbit followed by its burning in the Earth's atmosphere. The methodology is based on the use of a criterion for the equivalence of two plasma beam exposure regimes (in the Earth' ionosphere and in laboratory conditions) and an accelerated test procedure in what concerns space debris object material sputtering and space debris object erosion by a plasma beam in the Earth's ionosphere. The space debris coating material (blanket thermal insulation) sputtering yield and normal and tangential momentum transfer coefficients are determined experimentally as a function of the ion energy and the ion beam incidence angle.

  12. Magnetic nulls in three-dimensional kinetic simulations of space plasmas

    Science.gov (United States)

    Olshevsky, Vyacheslav; Deca, Jan; Divin, Andrey; Peng, Ivy Bo; Markidis, Stefano; Innocenti, Maria Elena; Cazzola, Emanuele; Lapenta, Giovanni

    2016-04-01

    We present a survey of magnetic nulls and associated energy dissipation in different three-dimensional kinetic particle-in-cell simulations of space plasmas. The configurations under study include: a traditional Harris current sheet and current sheets with asymmetric density distribution, dipolar and quadrupolar planetary magnetospheres, lunar magnetic anomalies, and decaying turbulence. Nulls are detected in the simulation snapshots by the topological degree method. In all runs except the quadrupolar magnetospere the dominating majority of nulls are of spiral topological type. When supported by strong currents, these nulls indicate the regions of strong energy dissipation. Dissipation, often accompanied by the changes in magnetic topology, is caused by plasma instabilities in the current channels or on their interfaces. Radial nulls show less activity, they can be created or destroyed in pairs, via topological bifurcations. Although such events demonstrate energy release, they are rather rare and short-living. An important implication of our study to observations is that magnetic topology should not be considered independently of other plasma properties such as currents.

  13. Particle-In-Cell Simulation on the Characteristics of a Receiving Antenna in Space Plasma Environment

    Science.gov (United States)

    Miyake, Yohei; Usui, Hideyuki; Kojima, Hirotsugu; Omura, Yoshiharu

    2008-12-01

    We applied the electromagnetic Particle-In-Cell simulation to the analysis of receiving antenna characteristics in space plasma environment. In the analysis, we set up external waves in a simulation region and receive them with a numerical antenna model placed in the simulation region. Using this method, we evaluated the effective length of electric field antennas used for plasma wave investigations conducted by scientific spacecraft. We particularly focused on the effective length of an electric field instrument called MEFISTO for a future mission to Mercury: BepiColombo. We first confirmed that the effective length of the MEFISTO-type antenna is basically longer than that of a simple dipole antenna for both electrostatic and electromagnetic plasma waves. By applying the principle of a voltmeter, the effective length of the MEFISTO-type antenna is predicted to become identical to the separation between two sensor-conductor's midpoints. However, the numerical result revealed that the actual effective length becomes shorter than the prediction, which is caused by the shorting-out effect due to the presence of a center boom conductor between the two sensor conductors. Since the above effect is difficult to treat theoretically, the present numerical method is a powerful tool for further quantitative evaluation of the antenna characteristics.

  14. The Deflection Plate Analyzer: A Technique for Space Plasma Measurements Under Highly Disturbed Conditions

    Science.gov (United States)

    Wright, Kenneth H., Jr.; Dutton, Ken; Martinez, Nelson; Smith, Dennis; Stone, Nobie H.

    2004-01-01

    A technique has been developed to measure the characteristics of space plasmas under highly disturbed conditions; e.g., non-Maxwellian plasmas with strong drifting populations and plasmas contaminated by spacecraft outgassing. The present method is an extension of the capabilities of the Differential Ion Flux Probe (DIFP) to include a mass measurement that does not include either high voltage or contamination sensitive devices such as channeltron electron multipliers or microchannel plates. This reduces the complexity and expense of instrument fabrication, testing, and integration of flight hardware as compared to classical mass analyzers. The new instrument design is called the Deflection Plate Analyzer (DPA) and can deconvolve multiple ion streams and analyze each stream for ion flux intensity (density), velocity (including direction of motion), mass, and temperature (or energy distribution). The basic functionality of the DPA is discussed. The performance characteristics of a flight instrument as built for an electrodynamic tether mission, the Propulsive Small Expendable Deployer System (ProSEDS), and the instrument s role in measuring key experimental conditions are also discussed.

  15. Plasma soluble prion protein, a potential biomarker for sport-related concussions: a pilot study.

    Directory of Open Access Journals (Sweden)

    Nam Pham

    Full Text Available Sport-related mild traumatic brain injury (mTBI or concussion is a significant health concern to athletes with potential long-term consequences. The diagnosis of sport concussion and return to sport decision making is one of the greatest challenges facing health care clinicians working in sports. Blood biomarkers have recently demonstrated their potential in assisting the detection of brain injury particularly, in those cases with no obvious physical injury. We have recently discovered plasma soluble cellular prion protein (PrP(C as a potential reliable biomarker for blast induced TBI (bTBI in a rodent animal model. In order to explore the application of this novel TBI biomarker to sport-related concussion, we conducted a pilot study at the University of Saskatchewan (U of S by recruiting athlete and non-athlete 18 to 30 year-old students. Using a modified quantitative ELISA method, we first established normal values for the plasma soluble PrP(C in male and female students. The measured plasma soluble PrP(C in confirmed concussion cases demonstrated a significant elevation of this analyte in post-concussion samples. Data collected from our pilot study indicates that the plasma soluble PrP(C is a potential biomarker for sport-related concussion, which may be further developed into a clinical diagnostic tool to assist clinicians in the assessment of sport concussion and return-to-play decision making.

  16. Plasma soluble prion protein, a potential biomarker for sport-related concussions: a pilot study.

    Science.gov (United States)

    Pham, Nam; Akonasu, Hungbo; Shishkin, Rhonda; Taghibiglou, Changiz

    2015-01-01

    Sport-related mild traumatic brain injury (mTBI) or concussion is a significant health concern to athletes with potential long-term consequences. The diagnosis of sport concussion and return to sport decision making is one of the greatest challenges facing health care clinicians working in sports. Blood biomarkers have recently demonstrated their potential in assisting the detection of brain injury particularly, in those cases with no obvious physical injury. We have recently discovered plasma soluble cellular prion protein (PrP(C)) as a potential reliable biomarker for blast induced TBI (bTBI) in a rodent animal model. In order to explore the application of this novel TBI biomarker to sport-related concussion, we conducted a pilot study at the University of Saskatchewan (U of S) by recruiting athlete and non-athlete 18 to 30 year-old students. Using a modified quantitative ELISA method, we first established normal values for the plasma soluble PrP(C) in male and female students. The measured plasma soluble PrP(C) in confirmed concussion cases demonstrated a significant elevation of this analyte in post-concussion samples. Data collected from our pilot study indicates that the plasma soluble PrP(C) is a potential biomarker for sport-related concussion, which may be further developed into a clinical diagnostic tool to assist clinicians in the assessment of sport concussion and return-to-play decision making.

  17. Equation of state of a quark-gluon plasma using the Cornell potential

    Science.gov (United States)

    Udayanandan, K. M.; Sethumadhavan, P.; Bannur, V. M.

    2007-10-01

    The equation of state (EOS) of quark-gluon plasma (QGP) using the Cornell potential based on Mayer's cluster expansion is presented. The string constant and the strong coupling constant for QGP are calculated. The EOS developed could describe the lattice EOS for pure gauge, two-flavor and three-flavor QGP qualitatively.

  18. Dynamic interaction potential and the scattering cross sections of the semiclassical plasma particles

    Energy Technology Data Exchange (ETDEWEB)

    Dzhumagulova, K. N.; Shalenov, E. O.; Gabdullina, G. L. [IETP, Al Farabi Kazakh National University, 71al Farabi Street, Almaty 050040 (Kazakhstan)

    2013-04-15

    The dynamic model of the charged particles interaction in non-ideal semiclassical plasma is presented. This model takes into account the quantum mechanical diffraction effect and the dynamic screening effect. On the basis of the dynamic interaction potential, the electron scattering cross sections are investigated. Comparison with the results obtained on the basis of other models and conclusions were made.

  19. Approximate, semi-implicit calculation of 3D electrostatic potential in a self-consistent plasma simulation

    Energy Technology Data Exchange (ETDEWEB)

    Keiter, E.R.; Kushner, M.J. [Univ. of Illinois, Urbana, IL (United States). Dept. of Electrical and Computer Engineering

    1997-12-31

    Numerical Modeling of low pressure plasma reactors is subject to numerous time step constraints, and among the most restrictive of these is the dielectric relaxation time. In recent years, semi-implicit flux-correction techniques have allowed plasma modelers to loosen the dielectric relaxation time step restriction. However, since these simulations do solve a form of Poisson`s equation, they still have a restriction on time step based on a modified, albeit less restrictive, dielectric relaxation time. For some parameter spaces this is acceptable, but for very large scale simulations (for example in three dimensions) and for simulations of systems having long time scales, obtaining a longer time step is crucial. Using a generalization of a technique already presented, the authors present a method for obtaining an approximate electrostatic potential which has no dielectric relaxation time restriction. Implementation is of comparable difficulty to that of a conventional Poisson`s equation, and is no more computationally intensive. The module is implemented within a large, self-consistent hybrid plasma equipment model (HPEM). A rearranged continuity equation is solved, and charge neutrality is assumed. A comparison to the HPEM running with Poisson`s equation is presented, for both two and three dimensions, and for electropositive and electronegative gases.

  20. Platelet-rich plasma gel composited with nondegradable porous polyurethane scaffolds as a potential auricular cartilage alternative.

    Science.gov (United States)

    Wang, Zhongshan; Qin, Haiyan; Feng, Zhihong; Zhao, Yimin

    2016-02-01

    Total auricular reconstruction is still a challenge, and autologous cartilage transplant is the main therapy so far. Tissue engineering provides a promising method for auricular cartilage reconstruction. However, although degradable framework demonstrated excellent initial cosmetic details, it is difficult to maintain the auricular contour over time and the metabolites tended to be harmful to human body. In this study, biocompatible and safe nondegradable elastic polyurethane was used to make porous scaffold in specific details by rapid prototyping technology. Platelet-rich plasma contains fibrin and abundant autologous growth factors, which was used as cell carriers for in vitro expanded cells. When crosslinking polyurethane framework, platelet-rich plasma and cells together, we successfully made polyurethane/platelet-rich plasma/cell composites, and implanted them into dorsal subcutaneous space of nude mice. The results showed that this method resulted in more even cell distribution and higher cell density, promoted chondrocyte proliferation, induced higher level expressions of aggrecan and type II collagen gene, increased content of newly developed glycosaminoglycans, and produced high-quality cartilaginous tissue. This kind of cartilage tissue engineering approach may be a potential promising alternative for external ear reconstruction.

  1. Potential markets for application of space medicine achievements

    Science.gov (United States)

    Orlov, Oleg; Belakovskiy, Mark; Kussmaul, Anna

    2014-11-01

    The Institute of Biomedical Problems (IBMP) is the lead institution of the Russian Federation in the area of space biology and medicine. It has successfully implemented a set of innovation-based activities and projects to develop and introduce promising space products and technologies into the practices of Earth health care. To this end, various investigative methods developed for the medical selection of cosmonauts have been successfully applied in ophthalmology, gastroenterology, and cardiology. Axial loading “Regent” suits and soil simulators of bearing load have proved their efficiency in rehabilitating patients with motor disorders. Developmental prototypes of versatile training devices and technologies of their application are used for rehabilitation and purposeful development of physical status in people of various age groups. The application of telemedicine technologies allows one to diagnose and treat diseases in people who are in remote locations from medical centers or happen to be in extreme conditions. In cooperation with leading national medical institutions, other developments by the Institute have been also introduced into clinical practice: for example, the method of assessing the human functional state on the basis of computerized analysis of cardiac rhythm indices; methods of diagnosing, treating and preventing osteoporosis and metabolic osteopathias; methods of treating cardiorespiratory diseases using warmed-up heliox mixtures; methods of prophylactic examination and assessing the physical health status of the population; methods of monitoring the functional state and enhancing the physical capacity of athletes; developmental models of devices for simulating the effects of artificial gravity for refining methods of treatment and rehabilitation of patients; and systems of IV anesthesia with an option of a remote control. The effective management of innovation-based activities and the issues of commercialization of promising developments and

  2. Cross-field flow and electric potential in a plasma slab

    Directory of Open Access Journals (Sweden)

    J. De Keyser

    2013-08-01

    Full Text Available We consider cross-field plasma flow inside a field-aligned plasma slab embedded in a uniform background in a 1-dimensional geometry. This situation may arise, for instance, when long-lasting reconnection pulses inject plasma into the inner magnetosphere. The present paper presents a detailed analysis of the structure of the interfaces that separate the slab from the background plasma on either side; a fully kinetic model is used to do so. Since the velocity shear across both interfaces has opposite signs, and given the typical gyroradius differences between injected and background ions and electrons, the structure of both interfaces can be very different. The behaviour of the slab and its interfaces depends critically on the flow of the plasma transverse to the magnetic field; in particular, it is shown that there are bounds to the flow speed that can be supported by the magnetised plasma. Further complicating the picture is the effect of the potential difference between the slab and its environment.

  3. Quantification of plasma exosome is a potential prognostic marker for esophageal squamous cell carcinoma.

    Science.gov (United States)

    Matsumoto, Yasunori; Kano, Masayuki; Akutsu, Yasunori; Hanari, Naoyuki; Hoshino, Isamu; Murakami, Kentaro; Usui, Akihiro; Suito, Hiroshi; Takahashi, Masahiko; Otsuka, Ryota; Xin, Hu; Komatsu, Aki; Iida, Keiko; Matsubara, Hisahiro

    2016-11-01

    Exosomes play important roles in cancer progression. Although its contents (e.g., proteins and microRNAs) have been focused on in cancer research, particularly as potential diagnostic markers, the exosome behavior and methods for exosome quantification remain unclear. In the present study, we analyzed the tumor-derived exosome behavior and assessed the quantification of exosomes in patient plasma as a biomarker for esophageal squamous cell carcinoma (ESCC). A CD63-GFP expressing human ESCC cell line (TE2-CD63-GFP) was made by transfection, and mouse subcutaneous tumor models were established. Fluorescence imaging was performed on tumors and plasma exosomes harvested from mice. GFP-positive small vesicles were confirmed in the plasma obtained from TE2-CD63-GFP tumor-bearing mice. Patient plasma was collected in Chiba University Hospital (n=86). Exosomes were extracted from 100 µl of the plasma and quantified by acetylcholinesterase (AChE) activity. The relationship between exosome quantification and the patient clinical characteristics was assessed. The quantification of exosomes isolated from the patient plasma revealed that esophageal cancer patients (n=66) expressed higher exosome levels than non-malignant patients (n=20) (P=0.0002). Although there was no correlation between the tumor progression and the exosome levels, exosome number was the independent prognostic marker and low levels of exosome predicted a poor prognosis (P=0.03). In conclusion, exosome levels may be useful as an independent prognostic factor for ESCC patients.

  4. Quantification of plasma exosome is a potential prognostic marker for esophageal squamous cell carcinoma

    Science.gov (United States)

    Matsumoto, Yasunori; Kano, Masayuki; Akutsu, Yasunori; Hanari, Naoyuki; Hoshino, Isamu; Murakami, Kentaro; Usui, Akihiro; Suito, Hiroshi; Takahashi, Masahiko; Otsuka, Ryota; Xin, Hu; Komatsu, Aki; Iida, Keiko; Matsubara, Hisahiro

    2016-01-01

    Exosomes play important roles in cancer progression. Although its contents (e.g., proteins and microRNAs) have been focused on in cancer research, particularly as potential diagnostic markers, the exosome behavior and methods for exosome quantification remain unclear. In the present study, we analyzed the tumor-derived exosome behavior and assessed the quantification of exosomes in patient plasma as a biomarker for esophageal squamous cell carcinoma (ESCC). A CD63-GFP expressing human ESCC cell line (TE2-CD63-GFP) was made by transfection, and mouse subcutaneous tumor models were established. Fluorescence imaging was performed on tumors and plasma exosomes harvested from mice. GFP-positive small vesicles were confirmed in the plasma obtained from TE2-CD63-GFP tumor-bearing mice. Patient plasma was collected in Chiba University Hospital (n=86). Exosomes were extracted from 100 µl of the plasma and quantified by acetylcholinesterase (AChE) activity. The relationship between exosome quantification and the patient clinical characteristics was assessed. The quantification of exosomes isolated from the patient plasma revealed that esophageal cancer patients (n=66) expressed higher exosome levels than non-malignant patients (n=20) (P=0.0002). Although there was no correlation between the tumor progression and the exosome levels, exosome number was the independent prognostic marker and low levels of exosome predicted a poor prognosis (P=0.03). In conclusion, exosome levels may be useful as an independent prognostic factor for ESCC patients. PMID:27599779

  5. Drag force of Anisotropic plasma at finite U(1) chemical potential

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Long; Ge, Xian-Hui [Shanghai University, Department of Physics, Shanghai (China); Wu, Shang-Yu [National Chiao Tung University, Department of Electrophysics, Yau Shing Tung Center, Hsinchu (China); National Center for Theoretical Science, Hsinchu (China)

    2016-05-15

    We perform the calculation of the drag force acting on a massive quark moving through an anisotropic N = 4 SU(N) Super Yang-Mills plasma in the presence of a U(1) chemical potential. We present the numerical results for any value of the anisotropy and arbitrary direction of the quark velocity with respect to the direction of the anisotropy. We find the effect of the chemical potential or charge density will enhance the drag force for our charged solution. (orig.)

  6. Expanding the Capabilities of the Pulsed Plasma Thruster for In-Space and Atmospheric Operation

    Science.gov (United States)

    Johnson, Ian Kronheim

    Of all in-space propulsion systems to date, the Pulsed Plasma Thruster (PPT) is unique in its simplicity and wide range of operational parameters. This study examined multiple uses of the thruster for in-space and atmospheric propulsion, as well as the creation of a CubeSat satellite and atmospheric airship as test beds for the thruster. The PPT was tested as a solid-propellant feed source for the High Power Helicon Thruster, a compact plasma source capable of generating order of magnitude higher plasma densities than comparable power level systems. Replacing the gaseous feed system reduced the thruster size and complexity, as well as allowing for extremely discrete discharges, minimizing the influence of wall effects. Teflon (C2F4) has been the traditional propellant for PPTs due to a high exhaust velocity and ability to ablate without surface modification over long durations. A number of alternative propellants, including minerals and metallics commonly found on asteroids, were tested for use with the PPT. Compounds with significant fractions of sulfur showed the highest performance increase, with specific thrusts double that of Teflon. A PPT with sulfur propellant designed for CubeSat operation, as well as the subsystems necessary for autonomous operation, was built and tested in the laboratory. The PPT was modified for use at atmospheric pressures where the impulse was well defined as a function of the discharge chamber volume, capacitor energy, and background pressure. To demonstrate that the air-breathing PPT was a viable concept the device was launched on two atmospheric balloon flights.

  7. Separable Multichannel Momentum Space Potentials for Nuclear Reactions

    Science.gov (United States)

    Hlophe, Linda; Elster, Charlotte

    2016-09-01

    Many nuclei are deformed and their properties can be described using a rotational model. This involves defining a deformed surface of the nucleus and constructing the nucleon-nucleus interaction as a function of distance to the surface. Such a potential has non-zero matrix elements between different nuclear rotational states which are characterized by the spin-parity Iπ, leading to channel couplings. For specific reaction calculations, it is advantageous to have separable representations of the interaction matrix elements available. We develop separable representations following a scheme suggested by Ernst, Shakin, and Thaler (EST). Since optical potentials are complex and energy-dependent, the multichannel EST scheme is generalized to complex, energy-dependent separable potentials. In the case of proton-nucleus interactions the EST scheme is further extended to include charged particles. The multichannel EST scheme is applied to nucleon scattering off 12C, where the first two excited states (Iπ =2+ ,4+) are taken into account. Research for this project was supported in part by the US Department of Energy, Office of Science of Nuclear Physics under Contract No. DE-FG02-93ER40756.

  8. A family for miniature, easily reconfigurable particle sensors for space plasma measurements

    Science.gov (United States)

    Wieser, M.; Barabash, S.

    2016-12-01

    Over the last 15 years the Swedish Institute of Space Physics developed a line of miniaturized ion mass analyzers for space plasma studies with masses of 400-600 g and highly compact and dense design to minimize the volume. The sensors cover an energy range from few eV up to 15 keV and reach an angular coverage up to hemispherical and mass resolution up to 7, depending on application. The experience with this line of sensors demonstrates that a sensor mass of 400-600 g is a limit in the trade-off between scientifically valuable performance and the sensor mass. The Solar Wind Monitor (SWIM), part of the Sub-keV Atom Reflecting Analyzer (SARA) on board of the Indian Chandrayaan-1 mission to the Moon, was the first sensor in the line. A number of instruments derived from SWIM were built, each using the same basic architecture but adapted for the needs of the corresponding mission: the Miniature Ion Precipitation Analyzer (MIPA) on the European Space Agency's BepiColombo mission to Mercury, the Detector for Ions at Mars (DIM) for the Russian Phobos-Grunt mission and the Yinghuo Plasma Package Ion sensor (YPPi) for the Chinese Yinghuo-1 spacecraft (both to Mars), the Prisma Ion Mass Analyzer (PRIMA) for the Swedish PRISMA spacecraft to Earth orbit, the eXtra Small Analyzer of Neutrals (XASN) for the Russian Luna-Glob lander, and the Laboratory Ion Scattering Analyzer (LISA) used for laboratory studies. We review architecture, design, performance, and fields of application of the instruments in this family and give and outlook in future developments.

  9. Direct Measurements of the Ionization Potential Depression in a Dense Plasma

    Science.gov (United States)

    Ciricosta, O.; Vinko, S. M.; Chung, H.-K.; Cho, B.-I.; Brown, C. R. D.; Burian, T.; Chalupský, J.; Engelhorn, K.; Falcone, R. W.; Graves, C.; Hájková, V.; Higginbotham, A.; Juha, L.; Krzywinski, J.; Lee, H. J.; Messerschmidt, M.; Murphy, C. D.; Ping, Y.; Rackstraw, D. S.; Scherz, A.; Schlotter, W.; Toleikis, S.; Turner, J. J.; Vysin, L.; Wang, T.; Wu, B.; Zastrau, U.; Zhu, D.; Lee, R. W.; Heimann, P.; Nagler, B.; Wark, J. S.

    2012-08-01

    We have used the Linac Coherent Light Source to generate solid-density aluminum plasmas at temperatures of up to 180 eV. By varying the photon energy of the x rays that both create and probe the plasma, and observing the K-α fluorescence, we can directly measure the position of the K edge of the highly charged ions within the system. The results are found to disagree with the predictions of the extensively used Stewart-Pyatt model, but are consistent with the earlier model of Ecker and Kröll, which predicts significantly greater depression of the ionization potential.

  10. Enzymatic Modification of Plasma Low Density Lipoproteins in Rabbits: A Potential Treatment for Hypercholesterolemia

    Science.gov (United States)

    Labeque, Regine; Mullon, Claudy J. P.; Ferreira, Joao Paulo M.; Lees, Robert S.; Langer, Robert

    1993-04-01

    Phospholipase A_2 (EC 3.1.1.4) hydrolyzes certain phospholipids of low density lipoprotein (LDL). Plasma clearance of phospholipase A_2-modified human LDL is up to 17 times faster than that of native human LDL in hypercholesterolemic rabbits. Modification of blood lipoproteins of hypercholesterolemic rabbits was performed by using an extracorporeal circuit containing immobilized phospholipase A_2. After 90-min treatments, nearly 30% decreases in plasma cholesterol concentrations were observed. Erythrocyte, leukocyte, and platelet counts showed no net change after treatment. This technique does not require any fluid replacement or sorbent regeneration and offers a potential approach for lowering serum cholesterol and LDL levels.

  11. RP and RQA Analysis for Floating Potential Fluctuations in a DC Magnetron Sputtering Plasma

    Science.gov (United States)

    Sabavath, Gopikishan; Banerjee, I.; Mahapatra, S. K.

    2016-04-01

    The nonlinear dynamics of a direct current magnetron sputtering plasma is visualized using recurrence plot (RP) technique. RP comprises the recurrence quantification analysis (RQA) which is an efficient method to observe critical regime transitions in dynamics. Further, RQA provides insight information about the system’s behavior. We observed the floating potential fluctuations of the plasma as a function of discharge voltage by using Langmuir probe. The system exhibits quasi-periodic-chaotic-quasi-periodic-chaotic transitions. These transitions are quantified from determinism, Lmax, and entropy of RQA. Statistical investigations like kurtosis and skewness also studied for these transitions which are in well agreement with RQA results.

  12. Jump Conditions of a Non-Neutral Plasma Shock with Current and Potential Difference

    Institute of Scientific and Technical Information of China (English)

    胡希伟

    2002-01-01

    Jump conditions about the total momentum flux and energy flux in a non-neutral plasma shock with electric current and field are given, which are derived from the double fluid equations and the Poisson equation for electron and ion fluids. Furthermore, we derive the relations between the upstream and downstream velocities and temperatures, and the minimum upstream Mach number for the plasma shock existence M1min, which depend on the current through the shock front J0, the electric potential difference between the upstream and downstream of shock △φ, and the ion charge Z.

  13. Bohm potential effect on the propagation of electrostatic surface wave in semi-bounded quantum plasmas

    Science.gov (United States)

    Lee, Myoung-Jae; Jung, Young-Dae

    2017-02-01

    High frequency electrostatic wave propagation in a dense and semi-bounded electron quantum plasma is investigated with consideration of the Bohm potential. The dispersion relation for the surface mode of quantum plasma is derived and numerically analyzed. We found that the quantum effect enhances the frequency of the wave especially in the high wave number regime. However, the frequency of surface wave is found to be always lower than that of the bulk wave for the same quantum wave number. The group velocity of the surface wave for various quantum wave number is also obtained.

  14. Rethinking Potentials of Public Space and its Management Through Placemaking in Kuala Lumpur

    Directory of Open Access Journals (Sweden)

    Sulaiman Normah

    2016-01-01

    Full Text Available Public space takes many spatial forms, including parks, the streets, sidewalks and footpaths that connect an edge of a space between buildings or roadsides, hence are important spaces in an urban setting. In a city context, the public space frames the city image. Kuala Lumpur’s public spaces are typically made up of shopping streets. It allows an ambivalent space that encourages more activities and interactions through the continuity of the street. For that reason, street that brings out life and movement in an urban space is an ideal type of street. In maintaining public spaces and reinventing it, placemaking is a quest for engagement tool to help strengthening legal frameworks in order to protect the public space which is seen viable at a city level. This paper therefore, explores the potentials of public spaces and its management. It applies the case study method by means of investigating two areas in the city encompassing similar characteristics. Generally, the research is designed to test the theoretical framework in managing the public space and its key dimensions in shaping the quality of public space. The researcher then synthesizes the broad range of development of placemaking and the changing uses of public space. The findings will advance further understanding of a suitable application thus intensify the legal framework that shapes the quality of space and its management.

  15. Time and space correlated investigations of confinement effects due to static axial magnetic fields acting on laser produced carbon plasmas

    Science.gov (United States)

    Favre, Mario; Wyndham, Edmund; Veloso, Felipe; Bhuyan, Heman; Reyes, Sebastian; Ruiz, Hugo Marcelo; Caballero-Bendixsen, Luis Sebastian

    2016-10-01

    We present further detailed studies of the dynamics and plasma properties of a laser produced Carbon plasma expanding in a static axial magnetic field. The laser plasmas are produced in vacuum, 1 .10-6 Torr, using a graphite target, with a Nd:YAG laser, 3.5 ns, 340 mJ at 1.06 μm, focused at 2 .109 W/cm2, and propagate in static magnetic fields of maximum value 0.2 T. 15 ns time and spaced resolved OES is used to investigate plasma composition. 50 ns time resolved plasma imaging is used to visualize the plasma dynamics. A mm size B-dot probe is used, in combination with a Faraday cup, to characterize the interaction between the expanding plasma and the magnetic field. As a result of time and space correlated measurements, unique features of the laser plasma dynamics in the presence of the magnetic field are identified, which highlight the confinement effects of the static magnetic field Funded by project FONDECYT 1141119.

  16. Advanced Vacuum Plasma Spray (VPS) for a Robust, Longlife and Safe Space Shuttle Main Engine (SSME)

    Science.gov (United States)

    Holmes, Richard R.; Elam, Sandra K.; McKechnie, Timothy N.; Power, Christopher A.

    2010-01-01

    In 1984, the Vacuum Plasma Spray Lab was built at NASA/Marshall Space Flight Center for applying durable, protective coatings to turbine blades for the space shuttle main engine (SSME) high pressure fuel turbopump. Existing turbine blades were cracking and breaking off after five hot fire tests while VPS coated turbine blades showed no wear or cracking after 40 hot fire tests. Following that, a major manufacturing problem of copper coatings peeling off the SSME Titanium Main Fuel Valve Housing was corrected with a tenacious VPS copper coating. A patented VPS process utilizing Functional Gradient Material (FGM) application was developed to build ceramic lined metallic cartridges for space furnace experiments, safely containing gallium arsenide at 1260 degrees centigrade. The VPS/FGM process was then translated to build robust, long life, liquid rocket combustion chambers for the space shuttle main engine. A 5K (5,000 Lb. thrust) thruster with the VPS/FGM protective coating experienced 220 hot firing tests in pristine condition with no wear compared to the SSME which showed blanching (surface pulverization) and cooling channel cracks in less than 30 of the same hot firing tests. After 35 of the hot firing tests, the injector face plates disintegrated. The VPS/FGM process was then applied to spraying protective thermal barrier coatings on the face plates which showed 50% cooler operating temperature, with no wear after 50 hot fire tests. Cooling channels were closed out in two weeks, compared to one year for the SSME. Working up the TRL (Technology Readiness Level) to establish the VPS/FGM process as viable technology, a 40K thruster was built and is currently being tested. Proposed is to build a J-2X size liquid rocket engine as the final step in establishing the VPS/FGM process TRL for space flight.

  17. Differential proteomics of human seminal plasma: A potential target for searching male infertility marker proteins.

    Science.gov (United States)

    Tomar, Anil Kumar; Sooch, Balwinder Singh; Singh, Sarman; Yadav, Savita

    2012-04-01

    The clinical fertility tests, available in the market, fail to define the exact cause of male infertility in almost half of the cases and point toward a crucial need of developing better ways of infertility investigations. The protein biomarkers may help us toward better understanding of unknown cases of male infertility that, in turn, can guide us to find better therapeutic solutions. Many clinical attempts have been made to identify biomarkers of male infertility in sperm proteome but only few studies have targeted seminal plasma. Human seminal plasma is a rich source of proteins that are essentially required for development of sperm and successful fertilization. This viewpoint article highlights the importance of human seminal plasma proteome in reproductive physiology and suggests that differential proteomics integrated with functional analysis may help us in searching potential biomarkers of male infertility.

  18. Plasma DNA integrity index as a potential molecular diagnostic marker for breast cancer.

    Science.gov (United States)

    Kamel, Azza M; Teama, Salwa; Fawzy, Amal; El Deftar, Mervat

    2016-06-01

    Plasma DNA integrity index is increased in various malignancies including breast cancer, the most common cancer in women worldwide; early detection is crucial for successful treatment. Current screening methods fail to detect many cases of breast cancer at an early stage. In this study, we evaluated the level of plasma DNA integrity index in 260 females (95 with breast cancer, 95 with benign breast lesions, and 70 healthy controls) to verify its potential value in discriminating malignant from benign breast lesions. The criteria of the American Joint Committee on Cancer were used for staging of breast cancer patients. DNA integrity index was measured by real-time PCR. DNA integrity index was significantly higher in breast cancer than in benign breast patients and healthy subjects (P = cancer group was 85.3 % at 0.55 DNA integrity index cutoff. In conclusion, the plasma DNA integrity index may be a promising molecular diagnostic marker of malignancy in breast lesions.

  19. Amino acid composition of parturient plasma, the intervillous space of the placenta and the umbilical vein of term newborn infants

    Directory of Open Access Journals (Sweden)

    J.S. Camelo Jr.

    2004-05-01

    Full Text Available The objective of the present study was to determine the levels of amino acids in maternal plasma, placental intervillous space and fetal umbilical vein in order to identify the similarities and differences in amino acid levels in these compartments of 15 term newborns from normal pregnancies and deliveries. All amino acids, except tryptophan, were present in at least 186% higher concentrations in the intervillous space than in maternal venous blood, with the difference being statistically significant. This result contradicted the initial hypothesis of the study that the plasma amino acid levels in the placental intervillous space should be similar to those of maternal plasma. When the maternal venous compartment was compared with the umbilical vein, we observed values 103% higher on the fetal side which is compatible with currently accepted mechanisms of active amino acid transport. Amino acid levels of the placental intervillous space were similar to the values of the umbilical vein except for proline, glycine and aspartic acid, whose levels were significantly higher than fetal umbilical vein levels (average 107% higher. The elevated levels of the intervillous space are compatible with syncytiotrophoblast activity, which maintain high concentrations of free amino acids inside syncytiotrophoblast cells, permitting asymmetric efflux or active transport from the trophoblast cells to the blood in the intervillous space. The plasma amino acid levels in the umbilical vein of term newborns probably may be used as a standard of local normality for clinical studies of amino acid profiles.

  20. Visual evoked potentials and selective attention to points in space

    Science.gov (United States)

    Van Voorhis, S.; Hillyard, S. A.

    1977-01-01

    Visual evoked potentials (VEPs) were recorded to sequences of flashes delivered to the right and left visual fields while subjects responded promptly to designated stimuli in one field at a time (focused attention), in both fields at once (divided attention), or to neither field (passive). Three stimulus schedules were used: the first was a replication of a previous study (Eason, Harter, and White, 1969) where left- and right-field flashes were delivered quasi-independently, while in the other two the flashes were delivered to the two fields in random order (Bernoulli sequence). VEPs to attended-field stimuli were enhanced at both occipital (O2) and central (Cz) recording sites under all stimulus sequences, but different components were affected at the two scalp sites. It was suggested that the VEP at O2 may reflect modality-specific processing events, while the response at Cz, like its auditory homologue, may index more general aspects of selective attention.

  1. ROGER a potential orbital space debris removal system

    Science.gov (United States)

    Starke, Juergen; Bischof, Bernd; Foth, W.-O.; -J., J.; Günther

    The previous activities in the field of On Orbit Servicing studied in the 1990's included in partic-ular the capability of vehicles in GEO to capture and support satellites (mainly communication satellites) to enable repair and continuation of operations, and finally the controlled transfer the target into a permanent graveyard orbit. The specific capture tools for these applications were mostly based on robotic systems to capture and fix the target under specific dynamic constraints (e.g. slowly tumbling target) without damage, and to allow the stabilization, re-orientation and potential repair of the target and subsequent release or transport to the final disposal orbit. Due to the drastically increasing number of debris particularly in the Low Earth Orbits (SSO) the active debris removal is now necessary to counteract to the predicted debris production cascade (Kessler Syndrome), which means the pollution of the total sphere in low earth orbit and not only the SSO area. In most of the debris congresses it was recommended to start removal with the still integrated systems as soon as possible. In the case of large debris objects, the soft capture system can be replaced by a simpler and robust system able to operate from a safe distance to the target and flexible enough to capture and hold different types of targets such as deactivated and/or defective satellites, upper stages and big fragments. These nominally non -cooperative targets might be partially destroyed by the capture process, but the production of additional debris shall be avoided. A major argument for the commercial applications is a multi-target mission potential, which is possible at GEO because the transfer propellant requirement to the disposal orbit and the return to the orbit of the next potential target is relative low (orbits with similar inclination and altitude). The proposed ROGER system is designed as a spacecraft with rendezvous capabilities including inspection in the vicinity of the

  2. Discrete Phase Space: Quantum mechanics and non-singular potential functions

    CERN Document Server

    Das, Anadijiban

    2015-01-01

    The three-dimensional potential equation, motivated by representations of quantum mechanics, is investigated in four different scenarios: (i) In the usual Euclidean space $\\mathbb{E}_{3}$ where the potential is singular but invariant under the continuous inhomogeneous orthogonal group $\\mathcal{I}O(3)$. The invariance under the translation subgroup is compared to the corresponding unitary transformation in the Schr\\"{o}dinger representation of quantum mechanics. This scenario is well known but serves as a reference point for the other scenarios. (ii) Next, the discrete potential equation as a partial difference equation in a three-dimensional lattice space is studied. In this arena the potential is non-singular but invariance under $\\mathcal{I}O(3)$ is broken. This is the usual picture of lattice theories and numerical approximations. (iii) Next we study the six-dimensional continuous phase space. Here a phase space representation of quantum mechanics is utilized. The resulting potential is singular but posse...

  3. Existence domains of slow and fast ion-acoustic solitons in two-ion space plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Maharaj, S. K., E-mail: smaharaj@sansa.org.za [South African National Space Agency (SANSA) Space Science, P.O. Box 32, Hermanus 7200 (South Africa); Bharuthram, R., E-mail: rbharuthram@uwc.ac.za [University of the Western Cape, Robert Sobukwe Road, Bellville, 7535 (South Africa); Singh, S. V., E-mail: satyavir@iigs.iigm.res.in; Lakhina, G. S., E-mail: lakhina@iigs.iigm.res.in [Indian Institute of Geomagnetism, New Panvel (West), Navi Mumbai 410218 (India)

    2015-03-15

    A study of large amplitude ion-acoustic solitons is conducted for a model composed of cool and hot ions and cool and hot electrons. Using the Sagdeev pseudo-potential formalism, the scope of earlier studies is extended to consider why upper Mach number limitations arise for slow and fast ion-acoustic solitons. Treating all plasma constituents as adiabatic fluids, slow ion-acoustic solitons are limited in the order of increasing cool ion concentrations by the number densities of the cool, and then the hot ions becoming complex valued, followed by positive and then negative potential double layer regions. Only positive potentials are found for fast ion-acoustic solitons which are limited only by the hot ion number density having to remain real valued. The effect of neglecting as opposed to including inertial effects of the hot electrons is found to induce only minor quantitative changes in the existence regions of slow and fast ion-acoustic solitons.

  4. The Effect of Polarization on the Stability of Current Sheaths in Space Plasma

    Science.gov (United States)

    Lyahov, Vladimir; Neshchadim, Vladimir

    2013-04-01

    The procedure of study of the stability of current sheath taking into account the effect of plasma polarization is proposed. The kinetic equation with self-consistent electromagnetic field for perturbation of distribution function is solved. On the basis of this solution the tensor of dielectric permeability of nonelectroneutral sharply-irregular current sheath plasma is calculated and the dispersion equation to study the possible instability modes of this sheath is obtained. Instability of the current sheath of magnetospheric tail with respect to the tearing-perturbations as well as influence of the effect of plasma polarization on the development of tearing instability is investigated. As a result of application of the offered procedure the existence of low-frequency tearing-like modes which essentially differ from the formerly known tiring-perturbations is revealed even for the case of an electroneutral current sheath. The increment of growth of those modes is positive within very wide interval of wave lengths and attains much bigger quantities than it was supposed earlier for the tearing-instability. Due to this polarization effect, the area of existence of those low-frequency tearing-like modes is displaced from the area of strong stationary electric field more close to the magnitoneutral (and electroneutral) plane at the center of symmetry of the current sheath. The problem of structural stability of the nonelectroneutral current sheath is explored. The equilibrium model represents a system of four connected non-linear first-order differential equations and hence it should manifest the property of structural instability - sensitivity to infinitesimal changes of the parameters and initial conditions. The solution for such current sheath is realized only in some areas of 7-dimensional space of model parameters. The phase volume of those areas is small in comparison with the entire phase volume in the interval on which the parameters are defined. The above is

  5. Surface Potential of Dust Grains at the Sheath Edge of Electronegative Dusty Plasmas

    Institute of Scientific and Technical Information of China (English)

    段萍; 王正汹; 王文春; 刘金远; 刘悦; 王晓钢

    2004-01-01

    In this paper we investigate the dust surface potential at the sheath edge of electronegative dusty plasmas theoretically, using the standard fluid model for the sheath and treating electrons and negative ions as Boltzmann particles but positive ions and dust grains as cold fluids.The dust charging model is self-consistently coupled with the sheath formation criterion by the dust surface potential and the ion Mach number, moreover the dust density variation is taken into account. The numerical results reveal that the dust number density and negative ion number density as well as its temperature can significantly affect the dust surface potential at the sheath edge.

  6. High-field plasma acceleration in a high-ionization-potential gas.

    Science.gov (United States)

    Corde, S; Adli, E; Allen, J M; An, W; Clarke, C I; Clausse, B; Clayton, C E; Delahaye, J P; Frederico, J; Gessner, S; Green, S Z; Hogan, M J; Joshi, C; Litos, M; Lu, W; Marsh, K A; Mori, W B; Vafaei-Najafabadi, N; Walz, D; Yakimenko, V

    2016-06-17

    Plasma accelerators driven by particle beams are a very promising future accelerator technology as they can sustain high accelerating fields over long distances with high energy efficiency. They rely on the excitation of a plasma wave in the wake of a drive beam. To generate the plasma, a neutral gas can be field-ionized by the head of the drive beam, in which case the distance of acceleration and energy gain can be strongly limited by head erosion. Here we overcome this limit and demonstrate that electrons in the tail of a drive beam can be accelerated by up to 27 GeV in a high-ionization-potential gas (argon), boosting their initial 20.35 GeV energy by 130%. Particle-in-cell simulations show that the argon plasma is sustaining very high electric fields, of ∼150 GV m(-1), over ∼20 cm. The results open new possibilities for the design of particle beam drivers and plasma sources.

  7. Study of energetic particle dynamics in Harbin Dipole eXperiment (HDX) on Space Plasma Environment Research Facility (SPERF)

    Science.gov (United States)

    Zhibin, W.; Xiao, Q.; Wang, X.; Xiao, C.; Zheng, J.; E, P.; Ji, H.; Ding, W.; Lu, Q.; Ren, Y.; Mao, A.

    2015-12-01

    Zhibin Wang1, Qingmei Xiao1, Xiaogang Wang1, Chijie Xiao2, Jinxing Zheng3, Peng E1, Hantao Ji1,5, Weixing Ding4, Quaming Lu6, Y. Ren1,5, Aohua Mao11 Laboratory for Space Environment and Physical Sciences, Harbin Institute of Technology, Harbin, China 150001 2 State Key Lab of Nuclear Physics & Technology, and School of Physics, Peking University, Beijing, China 100871 3ASIPP, Hefei, China, 230031 4University of California at Los Angeles, Los Angeles, CA, 90095 5Princeton Plasma Physics Laboratory, Princeton University, Princeton, NJ 08543 6University of Science and Technology of China, Hefei, China, 230026 A new terrella device for laboratory studies of space physics relevant to the inner magnetospheric plasmas, Harbin Dipole eXperiment (HDX), is scheduled to be built at Harbin Institute of Technology (HIT), China. HDX is one of two essential parts of Space Plasma Environment Research Facility (SPERF), which is a major national research facility for space physics studies. HDX is designed to provide a laboratory experimental platform to reproduce the earth's magnetospheric structure for investigations on the mechanism of acceleration/loss and wave-particle interaction of energetic particles in radiation belt, and on the influence of magnetic storms on the inner magnetosphere. It can be operated together with Harbin Reconnection eXperiment (HRX), which is another part of SPERF, to study the fundamental processes during interactions between solar wind and Earth's magnetosphere. In this presentation, the scientific goals and experimental plans for HDX, together with the means applied to generate the plasma with desired parameters, including multiple plasma sources and different kinds of coils with specific functions, as well as advanced diagnostics designed to be equipped to the facility for multi-functions, are reviewed. Three typical scenarios of HDX with operations of various coils and plasma sources to study specific physical processes in space plasmas will also be

  8. An Instrument for Measuring the Near-Surface PlasmaTemperature and Concentration, and the Surface Charging of the International Space Station

    Science.gov (United States)

    Kirov, B.

    2010-12-01

    The Langmuir probe is one of the classical instruments for plasma diagnostics [1] and among the first space-borne instruments. Langmuir probes have been successfully used aboard a number of rockets and satellites for in situ measurements of thermal plasma parameters in the terrestrial ionosphere [2], at other planets [3] and comets [4], and recently it is an indispensable instrument for measuring the satellite surface potential. In the present paper we discuss some theoretical and practical aspects of the application of the Langmuir probe for ionospheric measurements. We show that the spherical probe cannot be used for measurements in the ionosphere, and for the cylindrical probe the experimental Volt-Ampere curves are not described by the formula for an infinite cylinder. A formula is proposed for processing of this region. We demonstrate that in the case of two prevailing ions, their concentration can be found from the ion saturation region. Finally, we describe the two Langmuir probes designed and manufactured in Bulgaria, a part of the Plasma Wave Complex PWC (Obstanovka experiment) aboard the Russian segment of the International Space Station, whose goal is to monitor the surface charging and the noises and disturbances in the surrounding plasma induced by the station and by the experiments conducted aboard it.

  9. Characterization of plasma thiol redox potential in a common marmoset model of aging

    Directory of Open Access Journals (Sweden)

    James R. Roede

    2013-01-01

    Full Text Available Due to its short lifespan, ease of use and age-related pathologies that mirror those observed in humans, the common marmoset (Callithrix jacchus is poised to become a standard nonhuman primate model of aging. Blood and extracellular fluid possess two major thiol-dependent redox nodes involving cysteine (Cys, cystine (CySS, glutathione (GSH and glutathione disulfide (GSSG. Alteration in these plasma redox nodes significantly affects cellular physiology, and oxidation of the plasma Cys/CySS redox potential (EhCySS is associated with aging and disease risk in humans. The purpose of this study was to determine age-related changes in plasma redox metabolites and corresponding redox potentials (Eh to further validate the marmoset as a nonhuman primate model of aging. We measured plasma thiol redox states in marmosets and used existing human data with multivariate adaptive regression splines (MARS to model the relationships between age and redox metabolites. A classification accuracy of 70.2% and an AUC of 0.703 were achieved using the MARS model built from the marmoset redox data to classify the human samples as young or old. These results show that common marmosets provide a useful model for thiol redox biology of aging.

  10. Plasma physics and environmental perturbation laboratory. [magnetospheric experiments from space shuttle

    Science.gov (United States)

    Vogl, J. L.

    1973-01-01

    Current work aimed at identifying the active magnetospheric experiments that can be performed from the Space Shuttle, and designing a laboratory to carry out these experiments is described. The laboratory, known as the PPEPL (Plasma Physics and Environmental Perturbation Laboratory) consists of 35-ft pallet of instruments connected to a 25-ft pressurized control module. The systems deployed from the pallet are two 50-m booms, two subsatellites, a high-power transmitter, a multipurpose accelerator, a set of deployable canisters, and a gimbaled instrument platform. Missions are planned to last seven days, during which two scientists will carry out experiments from within the pressurized module. The type of experiments to be performed are outlined.

  11. Abrupt onset of tongue deformation and phase space response of ions in magnetically-confined plasmas

    Science.gov (United States)

    Ida, K.; Kobayashi, T.; Itoh, K.; Yoshinuma, M.; Tokuzawa, T.; Akiyama, T.; Moon, C.; Tsuchiya, H.; Inagaki, S.; Itoh, S.-I.

    2016-10-01

    An abrupt onset of the new tongue-shaped deformation of magnetic surface in magnetized plasmas, which was conjectured in since the 1960s but has not been observed, is experimentally identified just before an abrupt onset of a large-scale collapse event. Two novel properties of the event are identified. First, the transition of symmetry of perturbation (rather than a growth of linearly unstable MHD modes) was found to be a key for the onset of abrupt collapse, i.e., the transition of symmetry gives a new route to the collapse from stable state. Second, as a phase-space response of ions, the distortion from Maxwell-Boltzmann distribution of epithermal ions was observed for the first time.

  12. In Situ Observations of Ion Scale Current Sheets and Associated Electron Heating in Turbulent Space Plasmas

    Science.gov (United States)

    Chasapis, A.; Retino, A.; Sahraoui, F.; Greco, A.; Vaivads, A.; Khotyaintsev, Y. V.; Sundkvist, D. J.; Canu, P.

    2014-12-01

    We present a statistical study of ion-scale current sheets in turbulent space plasma. The study was performed using in situ measurements from the Earth's magnetosheath downstream of the quasi-parallel shock. Intermittent structures were identified using the Partial Variance of Increments method. We studied the distribution of the identified structures as a function of their magnetic shear angle, the PVI index and the electron heating. The properties of the observed current sheets were different for high (>3) and low (3) structures that accounted for ~20% of the total. Those current sheets have high magnetic shear (>90 degrees) and were observed mostly in close proximity to the bow shock with their numbers reducing towards the magnetopause. Enhancement of the estimated electron temperature within these current sheets suggest that they are important for local electron heating and energy dissipation.

  13. Nonlinear dynamics of phase space zonal structures and energetic particle physics in fusion plasmas

    CERN Document Server

    Zonca, Fulvio; Briguglio, Sergio; Fogaccia, Giuliana; Vlad, Gregorio; Wang, Xin

    2014-01-01

    A general theoretical framework for investigating nonlinear dynamics of phase space zonal structures is presented in this work. It is then, more specifically, applied to the limit where the nonlinear evolution time scale is smaller or comparable to the wave-particle trapping period. In this limit, both theoretical and numerical simulation studies show that non-adiabatic frequency chirping and phase locking could lead to secular resonant particle transport on meso- or macro-scales. The interplay between mode structures and resonant particles then provides the crucial ingredient to properly understand and analyze the nonlinear dynamics of Alfv\\'en wave instabilities excited by non-perturbative energetic particles in burning fusion plasmas. Analogies with autoresonance in nonlinear dynamics and with superradiance in free electron lasers are also briefly discussed.

  14. Plasma physics and environmental perturbation laboratory. [magnetospheric experiments from space shuttle

    Science.gov (United States)

    Vogl, J. L.

    1973-01-01

    Current work aimed at identifying the active magnetospheric experiments that can be performed from the Space Shuttle, and designing a laboratory to carry out these experiments is described. The laboratory, known as the PPEPL (Plasma Physics and Environmental Perturbation Laboratory) consists of 35-ft pallet of instruments connected to a 25-ft pressurized control module. The systems deployed from the pallet are two 50-m booms, two subsatellites, a high-power transmitter, a multipurpose accelerator, a set of deployable canisters, and a gimbaled instrument platform. Missions are planned to last seven days, during which two scientists will carry out experiments from within the pressurized module. The type of experiments to be performed are outlined.

  15. Abrupt onset of tongue deformation and phase space response of ions in magnetically-confined plasmas

    Science.gov (United States)

    Ida, K.; Kobayashi, T.; Itoh, K.; Yoshinuma, M.; Tokuzawa, T.; Akiyama, T.; Moon, C.; Tsuchiya, H.; Inagaki, S.; Itoh, S.-I.

    2016-01-01

    An abrupt onset of the new tongue-shaped deformation of magnetic surface in magnetized plasmas, which was conjectured in since the 1960s but has not been observed, is experimentally identified just before an abrupt onset of a large-scale collapse event. Two novel properties of the event are identified. First, the transition of symmetry of perturbation (rather than a growth of linearly unstable MHD modes) was found to be a key for the onset of abrupt collapse, i.e., the transition of symmetry gives a new route to the collapse from stable state. Second, as a phase-space response of ions, the distortion from Maxwell-Boltzmann distribution of epithermal ions was observed for the first time. PMID:27796370

  16. The Relativistic Boltzmann Equation on Bianchi Type I Space Time for Hard Potentials

    Science.gov (United States)

    Noutchegueme, Norbert; Takou, Etienne; Tchuengue, E. Kamdem

    2017-08-01

    In this paper, we consider the Cauchy problem for the spatially homogeneous relativistic Boltzmann equation with small initial data. The collision kernel considered here is for a hard potentials case. The background space-time in which the study is done is the Bianchi type I space-time. Under certain conditions made on the scattering kernel and on the metric, a uniqueness global (in time) solution is obtained in a suitable weighted functional space.

  17. An explicit Ricci potential for the Universal Moduli Space of Vector Bundles

    DEFF Research Database (Denmark)

    Andersen, Jørgen Ellegaard; Poulsen, Niccolo Skovgård

    In this paper we modify the coordinate construction in [5] on the universal moduli space of pair consisting of a Riemann Surfaces and a stable holomorphic bundles on the Riemann Surface, so as to produce a new set of coordinates, which are in fact Kähler coordinates on this universal moduli space....... Further, we give a functional determinant formula for the Ricci potential of the universal moduli space....

  18. Relevant parameter space and stability of spherical tokamaks with a plasma center column

    Science.gov (United States)

    Lampugnani, L. G.; Garcia-Martinez, P. L.; Farengo, R.

    2017-02-01

    A spherical tokamak (ST) with a plasma center column (PCC) can be formed inside a simply connected chamber via driven magnetic relaxation. From a practical perspective, the ST-PCC could overcome many difficulties associated with the material center column of the standard ST reactor design. Besides, the ST-PCC concept can be regarded as an advanced helicity injected device that would enable novel experiments on the key physics of magnetic relaxation and reconnection. This is because the concept includes not only a PCC but also a coaxial helicity injector (CHI). This combination implies an improved level of flexibility in the helicity injection scheme required for the formation and sustainment phases. In this work, the parameter space determining the magnetic structure of the ST-PCC equilibria is studied under the assumption of fully relaxed plasmas. In particular, it is shown that the effect of the external bias field of the PCC and the CHI essentially depends on a single parameter that measures the relative amount of flux of these two entities. The effect of plasma elongation on the safety factor profile and the stability to the tilt mode are also analyzed. In the first part of this work, the stability of the system is explained in terms of the minimum energy principle, and relevant stability maps are constructed. While this picture provides an adequate insight into the underlying physics of the instability, it does not include the stabilizing effect of line-tying at the electrodes. In the second part, a dynamical stability analysis of the ST-PCC configurations, including the effect of line-tying, is performed by numerically solving the magnetohydrodynamic equations. A significant stability enhancement is observed when the PCC contains more than the 70% of the total external bias flux, and the elongation is not higher than two.

  19. A comparison of inflection point and floating point emissive probe techniques for electric potential measurements in a Hall thruster plasma

    Science.gov (United States)

    Sheehan, J. P.; Raitses, Yevgeny; Hershkowitz, Noah; Fisch, Nathaniel

    2010-11-01

    Theory suggests that when increasing the electron emission of an emissive probe the floating potential will saturate ˜Te/e below the plasma potential. This can introduce significant errors in plasma potential measurements in Hall thrusters where Te> 10 eV. The method of determining the plasma potential from the inflection point of emissive IV traces in the limit of zero emission may give a more accurate measurement of the plasma potential. The two methods are compared in a Hall thruster where ne˜10^11 cm-3, Te˜20 eV, and ion flows are significant. The results can be generalized to other types of plasmas.

  20. A simple 3D plasma instrument with an electrically adjustable geometric factor for space research

    Science.gov (United States)

    Rohner, U.; Saul, L.; Wurz, P.; Allegrini, F.; Scheer, J.; McComas, D.

    2012-02-01

    We report on the design and experimental verification of a novel charged particle detector and an energy spectrometer with variable geometric factor functionality. Charged particle populations in the inner heliosphere create fluxes that can vary over many orders of magnitude in flux intensity. Space missions that plan to observe plasma fluxes, for example when travelling close to the Sun or to a planetary magnetosphere, require rapid particle measurements over the full three-dimensional velocity distribution. Traditionally, such measurements are carried out with plasma instrumentation with a fixed geometrical factor, which can only operate in a limited range of flux intensity. Here we report on the design and testing of a prototype sensor, which is capable of measuring particle flux with high angular and energy resolution, yet has a variable geometric factor that is controlled without moving parts. This prototype was designed in support of a proposal to make fast electron measurements on the Solar Probe Plus (SP+) mission planned by NASA. We simulated the ion optics inside the instrument and optimized the performance to design and build our prototype. This prototype was then tested in the MEFISTO facility at the University of Bern and its performance was verified over the full range of azimuth, elevation, energy and intensity.

  1. AMITIS: A 3D GPU-Based Hybrid-PIC Model for Space and Plasma Physics

    Science.gov (United States)

    Fatemi, Shahab; Poppe, Andrew R.; Delory, Gregory T.; Farrell, William M.

    2017-05-01

    We have developed, for the first time, an advanced modeling infrastructure in space simulations (AMITIS) with an embedded three-dimensional self-consistent grid-based hybrid model of plasma (kinetic ions and fluid electrons) that runs entirely on graphics processing units (GPUs). The model uses NVIDIA GPUs and their associated parallel computing platform, CUDA, developed for general purpose processing on GPUs. The model uses a single CPU-GPU pair, where the CPU transfers data between the system and GPU memory, executes CUDA kernels, and writes simulation outputs on the disk. All computations, including moving particles, calculating macroscopic properties of particles on a grid, and solving hybrid model equations are processed on a single GPU. We explain various computing kernels within AMITIS and compare their performance with an already existing well-tested hybrid model of plasma that runs in parallel using multi-CPU platforms. We show that AMITIS runs ∼10 times faster than the parallel CPU-based hybrid model. We also introduce an implicit solver for computation of Faraday’s Equation, resulting in an explicit-implicit scheme for the hybrid model equation. We show that the proposed scheme is stable and accurate. We examine the AMITIS energy conservation and show that the energy is conserved with an error < 0.2% after 500,000 timesteps, even when a very low number of particles per cell is used.

  2. A generalized AZ-non-Maxwellian velocity distribution function for space plasmas

    Science.gov (United States)

    Abid, A. A.; Khan, M. Z.; Lu, Quanming; Yap, S. L.

    2017-03-01

    A more generalized form of the non-Maxwellian distribution function, i.e., the AZ-distribution function is presented. Its fundamental properties are numerically observed by the variation of three parameters: α (rate of energetic particles on the shoulder), r (energetic particles on a broad shoulder), and q (superthermality on the tail of the velocity distribution curve of the plasma species). It has been observed that (i) the A Z - distribution function reduces to the ( r , q ) - distribution for α → 0 ; (ii) the A Z - distribution function reduces to the q - distribution for α → 0 , and r → 0 ; (iii) the A Z -distribution reduces to Cairns-distribution function for r → 0 , and q → ∞ ; (iv) the AZ-distribution reduces to Vasyliunas Cairns distribution for r → 0 , and q = κ + 1 ; (v) the AZ-distribution reduces to kappa distribution for α → 0 , r → 0 , and q = κ + 1 ; and (vi) finally, the AZ-distribution reduces to Maxwellian distribution for α → 0 , r → 0 , and q → ∞ . The uses of this more generalized A Z - distribution function in various space plasmas are briefly discussed.

  3. WEIGHTED ESTIMATES FOR COMMUTATORS OF POTENTIAL OPERATORS ON SPACES OF HOMOGENEOUS TYPE

    Institute of Scientific and Technical Information of China (English)

    Wenming Li; Xiaowu Yu; Xuefang Yan

    2009-01-01

    We derive some strong type and weak type weighted norm estimates which relate the commutators of potential integral operators to the corresponding maximal operators in the context of spaces of homogeneous type.

  4. An exploration of the effectiveness of artificial mini-magnetospheres as a potential Solar Storm shelter for long term human space missions

    CERN Document Server

    Bamford, Ruth; Bradford, John; Todd, Tom N; Stafford-Allen, Robin; Alves, E Paulo; Silva, Luis; Collingwood, Cheryl; Crawford, Ian A; Bingham, Robert

    2014-01-01

    In this paper we explore the effectiveness of an artificial mini-magnetosphere as a potential radiation shelter for long term human space missions. Our study includes the differences that the plasma environment makes to the efficiency of the shielding from the high energy charged particle component of solar and cosmic rays, which radically alters the power requirements. The incoming electrostatic charges are shielded by fields supported by the self captured environmental plasma of the solar wind, potentially augmented with additional density. The artificial magnetic field generated on board acts as the means of confinement and control. Evidence for similar behaviour of electromagnetic fields and ionised particles in interplanetary space can be gained by the example of the enhanced shielding effectiveness of naturally occurring "mini-magnetospheres" on the moon. The shielding effect of surface magnetic fields of the order of ~100s nanoTesla is sufficient to provide effective shielding from solar proton bombard...

  5. Potential space: creativity, resistance, and resiliency in the face of racism.

    Science.gov (United States)

    LaMothe, Ryan

    2012-12-01

    An amended version of Winnicott's concept of potential space is used to depict and understand the creativity, resilience, and resistance of African Americans facing the pervasive realities of social oppression, marginalization, and alienation linked to white racism. In particular, I argue that familial-communal potential space functions to confirm, secure, and maintain subjective and intersubjective experiences of being persons-unique, valued, inviolable, and agentic subjects-over and against the depersonalization of racism.

  6. Asymptotic Behavior for a Class of Modified -Potentials in a Half Space

    Directory of Open Access Journals (Sweden)

    Deng Guantie

    2010-01-01

    Full Text Available A class of -potentials represented as the sum of modified Green potential and modified Poisson integral are proved to have the growth estimates at infinity in the upper-half space of the -dimensional Euclidean space, where the function is a positive non-decreasing function on the interval satisfying certain conditions. This result generalizes the growth properties of analytic functions, harmonic functions, and superharmonic functions.

  7. On the limit cycle for the 1/r^2 potential in momentum space

    OpenAIRE

    Hammer, H. -W.; Swingle, Brian G.

    2005-01-01

    The renormalization of the attractive 1/r^2 potential has recently been studied using a variety of regulators. In particular, it was shown that renormalization with a square well in position space allows multiple solutions for the depth of the square well, including, but not requiring a renormalization group limit cycle. Here, we consider the renormalization of the 1/r^2 potential in momentum space. We regulate the problem with a momentum cutoff and absorb the cutoff dependence using a moment...

  8. Modified Jeans instability in Lorentzian dusty self-gravitating plasmas with Lennard-Jones potential

    Energy Technology Data Exchange (ETDEWEB)

    Qian, Y. Z., E-mail: qyzbird@live.com; Chen, H., E-mail: hchen61@ncu.edu.cn; Liu, S. Q., E-mail: sqlgroup@ncu.edu.cn [Department of Physics, Nanchang University, Nanchang 330047 (China)

    2014-11-15

    The Jeans instability in self-gravitating plasma with Kappa distributed dust grains is investigated basing on assumption that the mutual interaction among dust grains is governed by Lennard-Jones potential. It is shown that the presence of additional suprathermal particles has significant effects on the range of unstable modes and growth rate of Jeans instability. Compared with Maxwellian scenario, suprathermality stabilized the Jeans instability.

  9. 2D DIGE analysis of maternal plasma for potential biomarkers of Down Syndrome

    Directory of Open Access Journals (Sweden)

    Hogg Julie

    2011-09-01

    Full Text Available Abstract Background Prenatal screening for Down Syndrome (DS would benefit from an increased number of biomarkers to improve sensitivity and specificity. Improving sensitivity and specificity would decrease the need for potentially risky invasive diagnostic procedures. Results We have performed an in depth two-dimensional difference gel electrophoresis (2D DIGE study to identify potential biomarkers. We have used maternal plasma samples obtained from first and second trimesters from mothers carrying DS affected fetuses compared with mothers carrying normal fetuses. Plasma samples were albumin/IgG depleted and expanded pH ranges of pH 4.5 - 5.5, pH 5.3 - 6.5 and pH 6 - 9 were used for two-dimensional gel electrophoresis (2DE. We found no differentially expressed proteins in the first trimester between the two groups. Significant up-regulation of ceruloplasmin, inter-alpha-trypsin inhibitor heavy chain H4, complement proteins C1s subcomponent, C4-A, C5, and C9 and kininogen 1 were detected in the second trimester in maternal plasma samples where a DS affected fetus was being carried. However, ceruloplasmin could not be confirmed as being consistently up-regulated in DS affected pregnancies by Western blotting. Conclusions Despite the in depth 2DE approach used in this study the results underline the deficiencies of gel-based proteomics for detection of plasma biomarkers. Gel-free approaches may be more productive to increase the number of plasma biomarkers for DS for non-invasive prenatal screening and diagnosis.

  10. FCCP depolarizes plasma membrane potential by activating proton and Na+ currents in bovine aortic endothelial cells.

    Science.gov (United States)

    Park, Kyu-Sang; Jo, Inho; Pak, Kim; Bae, Sung-Won; Rhim, Hyewhon; Suh, Suk-Hyo; Park, Jin; Zhu, Hong; So, Insuk; Kim, Ki Whan

    2002-01-01

    We investigated the effects of carbonylcyanide p-trifluoromethoxyphenylhydrazone (FCCP), a protonophore and uncoupler of mitochondrial oxidative phosphorylation in mitochondria, on plasma membrane potential and ionic currents in bovine aortic endothelial cells (BAECs). The membrane potential and ionic currents of BAECs were recorded using the patch-clamp technique in current-clamp and voltage-clamp modes, respectively. FCCP activated ionic currents and depolarized the plasma membrane potential in a dose-dependent manner. Neither the removal of extracellular Ca2+ nor pretreatment with BAPTA/AM affected the FCCP-induced currents, implying that the currents are not associated with the FCCP-induced intracellular [Ca2+]i increase. FCCP-induced currents were significantly influenced by the changes in extracellular or intracellular pH; the increased proton gradient produced by lowering the extracellular pH or intracellular alkalinization augmented the changes in membrane potential and ionic currents caused by FCCP. FCCP-induced currents were significantly reduced under extracellular Na+-free conditions. The reversal potentials of FCCP-induced currents under Na+-free conditions were well fitted to the calculated equilibrium potential for protons. Interestingly, FCCP-induced Na+ transport (subtracted currents, I(control)- I(Na+-free) was closely dependent on extracellular pH, whereas FCCP-induced H+transport was not significantly affected by the absence of Na+. These results suggest that the FCCP-induced ionic currents and depolarization, which are strongly dependent on the plasmalemmal proton gradient, are likely to be mediated by both H+ and Na+ currents across the plasma membrane. The relationship between H+ and Na+ transport still needs to be determined.

  11. Nucleation rate of the quark-gluon plasma droplet at finite quark chemical potential

    Indian Academy of Sciences (India)

    D S Gosain; S Somorendro Singh; Agam K Jha

    2012-05-01

    The nucleation rate of quark-gluon plasma (QGP) droplet is computed at finite quark chemical potential. In the course of computing the nucleation rate, the finite size effects of the QGP droplet are taken into account. We consider the phenomenological flow parameter of quarks and gluons, which is dependent on quark chemical potential and we calculate the nucleation rate of the QGP droplet with this parameter. While calculating the nucleation rate, we find that for low values of quark phenomenological parameter $ q$, nucleation rate is negligible and when increases, nucleation rate increases significantly.

  12. Real-space formulation of the electrostatic potential and total energy of solids

    Energy Technology Data Exchange (ETDEWEB)

    Pask, J E; Sterne, P A

    2004-05-12

    We develop expressions for the electrostatic potential and total energy of crystalline solids which are amenable to direct evaluation in real space. Unlike conventional reciprocal space formulations, no Fourier transforms or reciprocal lattice summations are required, and the formulation is well suited for large-scale, parallel computations. The need for reciprocal space expressions is eliminated by replacing long-range potentials by equivalent localized charge distributions and incorporating long-range interactions into boundary conditions on the unit cell. In so doing, a simplification of the conventional reciprocal space formalism is obtained. The equivalence of the real- and reciprocal space formalisms is demonstrated by direct comparison in self-consistent density-functional calculations.

  13. In-Space Assembly Capability Assessment for Potential Human Exploration and Science Applications

    Science.gov (United States)

    Jefferies, Sharon A.; Jones, Christopher A.; Arney, Dale C.; Stillwagen, Frederic H.; Chai, Patrick R.; Hutchinson, Craig D.; Stafford, Matthew A.; Moses, Robert W.; Dempsey, James A.; Rodgers, Erica M.; hide

    2017-01-01

    Human missions to Mars present several major challenges that must be overcome, including delivering multiple large mass and volume elements, keeping the crew safe and productive, meeting cost constraints, and ensuring a sustainable campaign. Traditional methods for executing human Mars missions minimize or eliminate in-space assembly, which provides a narrow range of options for addressing these challenges and limits the types of missions that can be performed. This paper discusses recent work to evaluate how the inclusion of in-space assembly in space mission architectural concepts could provide novel solutions to address these challenges by increasing operational flexibility, robustness, risk reduction, crew health and safety, and sustainability. A hierarchical framework is presented to characterize assembly strategies, assembly tasks, and the required capabilities to assemble mission systems in space. The framework is used to identify general mission system design considerations and assembly system characteristics by assembly strategy. These general approaches are then applied to identify potential in-space assembly applications to address each challenge. Through this process, several focus areas were identified where applications of in-space assembly could affect multiple challenges. Each focus area was developed to identify functions, potential assembly solutions and operations, key architectural trades, and potential considerations and implications of implementation. This paper helps to identify key areas to investigate were potentially significant gains in addressing the challenges with human missions to Mars may be realized, and creates a foundation on which to further develop and analyze in-space assembly concepts and assembly-based architectures.

  14. Quantum-mechanical calculation of ionization potential lowering in dense plasmas

    CERN Document Server

    Son, Sang-Kil; Jurek, Zoltan; Ziaja, Beata; Santra, Robin

    2014-01-01

    The charged environment within a dense plasma leads to the phenomenon of ionization potential depression (IPD) for ions embedded in the plasma. Accurate predictions of the IPD effect are of crucial importance for modeling atomic processes occurring within dense plasmas. Several theoretical models have been developed to describe the IPD effect, with frequently discrepant predictions. Only recently, first experiments on IPD in Al plasma have been performed with an x-ray free-electron laser (XFEL), where their results were found to be in disagreement with the widely-used IPD model by Stewart and Pyatt. Another experiment on Al, at the Orion laser, showed disagreement with the model by Ecker and Kr\\"oll. This controversy shows a strong need for a rigorous and consistent theoretical approach to calculate the IPD effect. Here we propose such an approach: a two-step Hartree-Fock-Slater model. With this parameter-free model we can accurately and efficiently describe the experimental Al data and validate the accuracy ...

  15. Bohm potential effect on the propagation of electrostatic surface wave in semi-bounded quantum plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Myoung-Jae [Department of Physics, Hanyang University, Seoul 04763 (Korea, Republic of); Research Institute for Natural Sciences, Hanyang University, Seoul 04763 (Korea, Republic of); Jung, Young-Dae, E-mail: ydjung@hanyang.ac.kr [Department of Applied Physics and Department of Bionanotechnology, Hanyang University, Ansan, Kyunggi-Do 15588 (Korea, Republic of); Department of Electrical and Computer Engineering, MC 0407, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0407 (United States)

    2017-02-12

    High frequency electrostatic wave propagation in a dense and semi-bounded electron quantum plasma is investigated with consideration of the Bohm potential. The dispersion relation for the surface mode of quantum plasma is derived and numerically analyzed. We found that the quantum effect enhances the frequency of the wave especially in the high wave number regime. However, the frequency of surface wave is found to be always lower than that of the bulk wave for the same quantum wave number. The group velocity of the surface wave for various quantum wave number is also obtained. - Highlights: • High frequency electrostatic wave propagation is investigated in a dense semi-bounded quantum plasma. • The dispersion relation for the surface mode of quantum plasma is derived and numerically analyzed. • The quantum effect enhances the frequency of the wave especially in the high wave number regime. • The frequency of surface wave is found to be always lower than that of the bulk wave. • The group velocity of the surface wave for various quantum wave number is also obtained.

  16. Human muscle sympathetic nerve activity and plasma noradrenaline kinetics in space

    Science.gov (United States)

    Ertl, Andrew C.; Diedrich, Andre; Biaggioni, Italo; Levine, Benjamin D.; Robertson, Rose Marie; Cox, James F.; Zuckerman, Julie H.; Pawelczyk, James A.; Ray, Chester A.; Buckey, Jay C Jr; Lane, Lynda D.; Shiavi, Richard; Gaffney, F. Andrew; Costa, Fernando; Holt, Carol; Blomqvist, C. Gunnar; Eckberg, Dwain L.; Baisch, Friedhelm J.; Robertson, David

    2002-01-01

    Astronauts returning from space have reduced red blood cell masses, hypovolaemia and orthostatic intolerance, marked by greater cardio-acceleration during standing than before spaceflight, and in some, orthostatic hypotension and presyncope. Adaptation of the sympathetic nervous system occurring during spaceflight may be responsible for these postflight alterations. We tested the hypotheses that exposure to microgravity reduces sympathetic neural outflow and impairs sympathetic neural responses to orthostatic stress. We measured heart rate, photoplethysmographic finger arterial pressure, peroneal nerve muscle sympathetic activity and plasma noradrenaline spillover and clearance, in male astronauts before, during (flight day 12 or 13) and after the 16 day Neurolab space shuttle mission. Measurements were made during supine rest and orthostatic stress, as simulated on Earth and in space by 7 min periods of 15 and 30 mmHg lower body suction. Mean (+/- S.E.M.) heart rates before lower body suction were similar pre-flight and in flight. Heart rate responses to -30 mmHg were greater in flight (from 56 +/- 4 to 72 +/- 4 beats min(-1)) than pre-flight (from 56 +/- 4 at rest to 62 +/- 4 beats min(-1), P < 0.05). Noradrenaline spillover and clearance were increased from pre-flight levels during baseline periods and during lower body suction, both in flight (n = 3) and on post-flight days 1 or 2 (n = 5, P < 0.05). In-flight baseline sympathetic nerve activity was increased above pre-flight levels (by 10-33 %) in the same three subjects in whom noradrenaline spillover and clearance were increased. The sympathetic response to 30 mmHg lower body suction was at pre-flight levels or higher in each subject (35 pre-flight vs. 40 bursts min(-1) in flight). No astronaut experienced presyncope during lower body suction in space (or during upright tilt following the Neurolab mission). We conclude that in space, baseline sympathetic neural outflow is increased moderately and sympathetic

  17. Activities report of the National Space Research Institute Plasma Laboratory for the period 1988/1989; Relatorio de atividades do Laboratorio Associado de Plasma do INPE no bienio 88/89

    Energy Technology Data Exchange (ETDEWEB)

    Ludwig, Gerson Otto

    1990-11-01

    This report describes the activities performed in the period 1988/1989 by the National Space Research Institute (INPE/SCT) Plasma Laboratory (LAP). The report presents the main results in the following research lines: plasma physics, plasma technology, and controlled thermonuclear fusion. (author). 49 figs., 3 tabs.

  18. Two Dimensional LIF Measurements and Potential Structure of Ion Beam Formation in an Argon Helicon Plasma

    Science.gov (United States)

    Aguirre, Evan; Scime, Earl; Good, Timothy

    2016-10-01

    We report 2-dimensional, spatially resolved observations of ion beam formation in an expanding helicon plasma. Previous studies found that a current free double layer (CFDL) spontaneously arises at low pressure, below 1 mT. We use Laser Induced Fluorescence (LIF), a non-perturbative diagnostic to measure the ion velocity distribution functions (IVDFs) of argon ions both parallel and perpendicular to the background magnetic field. We report ion beam formation as a function of the expansion chamber magnetic field (0-108 G). The ion beam appears peaked in the center of the expansion chamber and decays over a few centimeters radially. We also report the potential structure of the plasma obtained with a planar Langmuir probe. To obtain meaningful Langmuir probe measurements, averages of tens of current-voltage are needed to reduce the effects of large electrostatic fluctuations that arise in plasmas that generate ion beams. We report the dependence of density, electron temperature, and floating potential on radial and axial position in the expansion plume. NSF Award PHYS-1360278.

  19. Electron cooling and finite potential drop in a magnetized plasma expansion

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-Sanchez, M. [Department of Aeronautics and Astronautics, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139 (United States); Navarro-Cavallé, J. [Escuela Técnica Superior de Ingeniería Aeronáutica y del Espacio, Universidad Politécnica de Madrid, Plaza Cardenal Cisneros 3, Madrid 28040 (Spain); Ahedo, E. [Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Avda. Universidad 30, Leganés 28911, Madrid (Spain)

    2015-05-15

    The steady, collisionless, slender flow of a magnetized plasma into a surrounding vacuum is considered. The ion component is modeled as mono-energetic, while electrons are assumed Maxwellian upstream. The magnetic field has a convergent-divergent geometry, and attention is restricted to its paraxial region, so that 2D and drift effects are ignored. By using the conservation of energy and magnetic moment of particles and the quasi-neutrality condition, the ambipolar electric field and the distribution functions of both species are calculated self-consistently, paying attention to the existence of effective potential barriers associated to magnetic mirroring. The solution is used to find the total potential drop for a set of upstream conditions, plus the axial evolution of various moments of interest (density, temperatures, and heat fluxes). The results illuminate the behavior of magnetic nozzles, plasma jets, and other configurations of interest, showing, in particular, in the divergent plasma the collisionless cooling of electrons, and the generation of collisionless electron heat fluxes.

  20. Potential biomarkers of fatigue identified by plasma metabolome analysis in rats.

    Directory of Open Access Journals (Sweden)

    Satoshi Kume

    Full Text Available In the present study, prior to the establishment of a method for the clinical diagnosis of chronic fatigue in humans, we validated the utility of plasma metabolomic analysis in a rat model of fatigue using capillary electrophoresis-mass spectrometry (CE-MS. In order to obtain a fatigued animal group, rats were placed in a cage filled with water to a height of 2.2 cm for 5 days. A food-restricted group, in which rats were limited to 10 g/d of food (around 50% of the control group, was also assessed. The food-restricted group exhibited weight reduction similar to that of the fatigued group. CE-MS measurements were performed to evaluate the profile of food intake-dependent metabolic changes, as well as the profile in fatigue loading, resulting in the identification of 48 metabolites in plasma. Multivariate analyses using hierarchical clustering and principal component analysis revealed that the plasma metabolome in the fatigued group showed clear differences from those in the control and food-restricted groups. In the fatigued group, we found distinctive changes in metabolites related to branched-chain amino acid metabolism, urea cycle, and proline metabolism. Specifically, the fatigued group exhibited significant increases in valine, leucine, isoleucine, and 2-oxoisopentanoate, and significant decreases in citrulline and hydroxyproline compared with the control and food-restricted groups. Plasma levels of total nitric oxide were increased in the fatigued group, indicating systemic oxidative stress. Further, plasma metabolites involved in the citrate cycle, such as cis-aconitate and isocitrate, were reduced in the fatigued group. The levels of ATP were significantly decreased in the liver and skeletal muscle, indicative of a deterioration in energy metabolism in these organs. Thus, this comprehensive metabolic analysis furthered our understanding of the pathophysiology of fatigue, and identified potential diagnostic biomarkers based on fatigue

  1. Potential biomarkers of fatigue identified by plasma metabolome analysis in rats.

    Science.gov (United States)

    Kume, Satoshi; Yamato, Masanori; Tamura, Yasuhisa; Jin, Guanghua; Nakano, Masayuki; Miyashige, Yukiharu; Eguchi, Asami; Ogata, Yoshiyuki; Goda, Nobuhito; Iwai, Kazuhiro; Yamano, Emi; Watanabe, Yasuyoshi; Soga, Tomoyoshi; Kataoka, Yosky

    2015-01-01

    In the present study, prior to the establishment of a method for the clinical diagnosis of chronic fatigue in humans, we validated the utility of plasma metabolomic analysis in a rat model of fatigue using capillary electrophoresis-mass spectrometry (CE-MS). In order to obtain a fatigued animal group, rats were placed in a cage filled with water to a height of 2.2 cm for 5 days. A food-restricted group, in which rats were limited to 10 g/d of food (around 50% of the control group), was also assessed. The food-restricted group exhibited weight reduction similar to that of the fatigued group. CE-MS measurements were performed to evaluate the profile of food intake-dependent metabolic changes, as well as the profile in fatigue loading, resulting in the identification of 48 metabolites in plasma. Multivariate analyses using hierarchical clustering and principal component analysis revealed that the plasma metabolome in the fatigued group showed clear differences from those in the control and food-restricted groups. In the fatigued group, we found distinctive changes in metabolites related to branched-chain amino acid metabolism, urea cycle, and proline metabolism. Specifically, the fatigued group exhibited significant increases in valine, leucine, isoleucine, and 2-oxoisopentanoate, and significant decreases in citrulline and hydroxyproline compared with the control and food-restricted groups. Plasma levels of total nitric oxide were increased in the fatigued group, indicating systemic oxidative stress. Further, plasma metabolites involved in the citrate cycle, such as cis-aconitate and isocitrate, were reduced in the fatigued group. The levels of ATP were significantly decreased in the liver and skeletal muscle, indicative of a deterioration in energy metabolism in these organs. Thus, this comprehensive metabolic analysis furthered our understanding of the pathophysiology of fatigue, and identified potential diagnostic biomarkers based on fatigue pathophysiology.

  2. Easy measurement of diffusion coefficients of EGFP-tagged plasma membrane proteins using k-space Image Correlation Spectroscopy

    DEFF Research Database (Denmark)

    Christensen, Eva Arnspang; Koffman, Jennifer Skaarup; Marlar, Saw

    2014-01-01

    Lateral diffusion and compartmentalization of plasma membrane proteins are tightly regulated in cells and thus, studying these processes will reveal new insights to plasma membrane protein function and regulation. Recently, k-Space Image Correlation Spectroscopy (kICS)1 was developed to enable...... to the correlation function yields the diffusion coefficient. This paper provides a step-by-step guide to the image analysis and measurement of diffusion coefficients via kICS. First, a high frame rate image sequence of a fluorescently labeled plasma membrane protein is acquired using a fluorescence microscope Then...... routine measurements of diffusion coefficients directly from images of fluorescently tagged plasma membrane proteins, that avoided systematic biases introduced by probe photophysics. Although the theoretical basis for the analysis is complex, the method can be implemented by nonexperts using a freely...

  3. A potential tool for diagnosis of male infertility: Plasma metabolomics based on GC-MS.

    Science.gov (United States)

    Zhou, Xinyi; Wang, Yang; Yun, Yonghuan; Xia, Zian; Lu, Hongmei; Luo, Jiekun; Liang, Yizeng

    2016-01-15

    Male infertility has become an important public health problem worldwide. Nowadays the diagnosis of male infertility frequently depends on the results of semen quality or requires more invasive surgical intervention. Therefore, it is necessary to develop a novel approach for early diagnosis of male infertility. According to the presence or absence of normal sexual function, the male infertility is classified into two phenotypes, erectile dysfunction (ED) and semen abnormalities (SA). The aim of this study was to investigate the GC-MS plasma profiles of infertile male having erectile dysfunction (ED) and having semen abnormalities (SA) and discover the potential biomarkers. The plasma samples from healthy controls (HC) (n=61) and infertility patients with ED (n=26) or with SA (n=44) were analyzed by gas chromatography-mass spectrometry (GC-MS) for discrimination and screening potential biomarkers. The partial least squares-discriminant analysis (PLS-DA) was performed on GC-MS dataset. The results showed that HC could be discriminated from infertile cases having SA (AUC=86.96%, sensitivity=78.69%, specificity=84.09%, accuracy=80.95%) and infertile cases having ED (AUC=94.33%, sensitivity=80.33%, specificity=100%, accuracy=87.36%). Some potential biomarkers were successfully discovered by two commonly used variable selection methods, variable importance on projection (VIP) and original coefficients of PLS-DA (β). 1,5-Anhydro-sorbitol and α-hydroxyisovaleric acid were identified as the potential biomarkers for distinguishing HC from the male infertility patients. Meanwhile, lactate, glutamate and cholesterol were the found to be the important variables to distinguish between patients with erectile dysfunction from those with semen abnormalities. The plasma metabolomics may be developed as a novel approach for fast, noninvasive, and acceptable diagnosis and characterization of male infertility.

  4. Integrated Multi-Point Space Plasma Measurements With Four Ionospheric Satellites

    Science.gov (United States)

    Siefring, C. L.; Bernhardt, P. A.; Selcher, C.; Wilkens, M. R.; McHarg, M. G.; Krause, L.; Chun, F.; Enloe, L.; Panholzer, R.; Sakoda, D.; Phelps, R.; D Roussel-Dupre, D.; Colestock, P.; Close, S.

    2006-12-01

    The STP-1 launch scheduled for late 2006 will place four satellites with ionospheric plasma diagnostics into the same nearly circular orbit with an altitude of 560 km and inclination of 35.4°. The satellites will allow for unique multipoint measurements of ionospheric scintillations and their causes. Both the radio and in-situ diagnostics will provide coverage of low- and mid-latitudes. The four satellites, STPSat1, NPSat1, FalconSat3, and CFE will follow the same ground-track but because of drag and mass differences their relative velocities will be different and vary during the lifetime of the satellites. The four satellites will start close together; separate over a few months and coming back together with near conjunctions at six and eight months. Two satellite conjunctions between NPSat1 and STPSat1 will occur most often, approximately one month apart at the end of the mission. STPSat1 is equipped with CITRIS (sCintillation and TEC Receiver In Space) which will measure scintillations in the VHF, UHF and L-band along with measuring Total Electron Content (TEC) along the propagation path. NPSat1 will carry a three-frequency CERTO (Coherent Electromagnetic Radio TOmography) Beacon which broadcasts phase-coherent signals at 150.012 MHz, 400.032 MHz, and 1066.752 MHz. CITRIS will be able to measure TEC and Scintillations along the orbital path (propagation path from NPSat1 to STPSat1) as well as between the CITRIS and the ground. NPSat1 carries electron and ion saturation Langmuir Probes, while FalconSat3 carries the FLAPS (FLAt Plasma Spectrometer) and PLANE (Plasma Local Anomalous Noise Environment). The in-situ diagnostic complement the CITRIS/CERTO radio techniques in many ways. The CIBOLA Flight Experiment (CFE) contains a wide band receiver covering 100 to 500 MHz. The CFE data can be processed to show distortion of wide-band modulations by ionospheric irregularities. CFE and CITRIS can record ground transmissions from the French DORIS beacons which radiate

  5. Second harmonic wave generation from a nonlinear combination of volume wave and overdense plasma in negative permeability space

    Science.gov (United States)

    Iwai, Akinori; Nakamura, Yoshihiro; Sakai, Osamu

    2016-09-01

    We clarify the relation between second harmonic wave (SH wave) and plasma generation in various experimental conditions by detecting properties of propagating electromagnetic waves (EM waves). Plasma has a nonlinear reaction against EM wave, generating harmonic waves which depends on electron density ne. In the case with increased ne, EM wave comes to be prevented from going into plasma with negative permittivity ɛp. Double-split-ring resonators (DSRRs), one of metamaterials, make permeability μD negative. We have shown that EM wave being volume wave can propagate into the combination of overdense plasma and DSRRs because of real negative value refractive index N. In our previous paper, we have confirmed enhanced SH wave (4.9 GHz) generation in the composite with 2.45-GHz input. In this report, we show the dependence of the SH wave emission with plasma generation on plasma parameters and gas conditions of plasma. Furthermore, we show the phase change with N variation of the composite space in the case with various input power as the proof of the negative index state.

  6. Magnetically insulated baffled probe for real-time monitoring of equilibrium and fluctuating values of space potentials, electron and ion temperatures, and densities.

    Science.gov (United States)

    Demidov, V I; Koepke, M E; Raitses, Y

    2010-10-01

    By restricting the electron-collection area of a cold Langmuir probe compared to the ion-collection area, the probe floating potential can become equal to the space potential, and thus conveniently monitored, rather than to a value shifted from the space potential by an electron-temperature-dependent offset, i.e., the case with an equal-collection-area probe. This design goal is achieved by combining an ambient magnetic field in the plasma with baffles, or shields, on the probe, resulting in species-selective magnetic insulation of the probe collection area. This permits the elimination of electron current to the probe by further adjustment of magnetic insulation which results in an ion-temperature-dependent offset when the probe is electrically floating. Subtracting the floating potential of two magnetically insulated baffled probes, each with a different degree of magnetic insulation, enables the electron or ion temperature to be measured in real time.

  7. Breakdown of a space charge limited regime of a sheath in a weakly collisional plasma bounded by walls with secondary electron emission.

    Science.gov (United States)

    Sydorenko, D; Kaganovich, I; Raitses, Y; Smolyakov, A

    2009-10-02

    A new regime of plasma-wall interaction is identified in particle-in-cell simulations of a hot plasma bounded by walls with secondary electron emission. Such a plasma has a strongly non-Maxwellian electron velocity distribution function and consists of bulk plasma electrons and beams of secondary electrons. In the new regime, the plasma sheath is not in a steady space charge limited state even though the secondary electron emission produced by the plasma bulk electrons is so intense that the corresponding partial emission coefficient exceeds unity. Instead, the plasma-sheath system performs relaxation oscillations by switching quasiperiodically between the space charge limited and non-space-charge limited states.

  8. On the exact solubility in momentum space of the trigonometric Rosen-Morse potential

    CERN Document Server

    Compean, C B

    2011-01-01

    The Schrodinger equation with the trigonometric Rosen-Morse potential in flat three dimensional Euclidean space, E3, and its exact solutions are shown to be also exactly transformable to momentum space, though the resulting equation is purely algebraic and can not be cast into the canonical form of an integral Lippmann-Schwinger equation. This is because the cotangent function does not allow for an exact Fourier transform in E3. In addition we recall, that the above potential can be also viewed as an angular function of the second polar angle parametrizing the three dimensional spherical surface, S3, of a constant radius, in which case the cotangent function would allow for an exact integral transform to momentum space. On that basis, we obtain a momentum space Lippmann-Schwinger-type equation, though the corresponding wavefunctions have to be obtained numerically.

  9. Synchronous plasma membrane electrochemical potential oscillations during yeast colony development and aging.

    Science.gov (United States)

    Palková, Zdena; Váchová, Libuse; Gásková, Dana; Kucerová, Helena

    2009-05-01

    Microorganisms that survive in natural environments form organized multicellular communities, biofilms and colonies with specific properties. During stress and nutrient limitation, slow growing and senescent cells in such communities retain vital processes by maintaining plasma membrane integrity and retaining the ability to generate transmembrane electrochemical gradients. We report the use of a Saccharomyces cerevisiae colonial model to show that population growth in a multicellular community depends on nutrient diffusion and that resting cells start to accumulate from the beginning of the second acidic phase of colony development. Despite differentiation of colony members, synchronous transmembrane potential oscillation was detected in the organized colony. The electrochemical membrane potential periodically oscillated at frequencies between those for circadian to infradian rhythms during colony aging and transiently decreased at time points previously linked with rebuilding of yeast metabolism. Despite extensive decreases in the intracellular ATP concentration and in the amount and activity of the plasma membrane proton pump during nutrient limited growth and colony aging, the transmembrane electrochemical potential appeared to be maintained above a level critical for population survival.

  10. A plasma source driven predator-prey like mechanism as a potential cause of spiraling intermittencies in linear plasma devices

    Energy Technology Data Exchange (ETDEWEB)

    Reiser, D. [Research Center Jülich GmbH, Institute for Energy and Climate Research—Plasma Physics, D-52425 Jülich (Germany); Ohno, N. [Department of Energy Engineering and Science, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Tanaka, H. [National Institute for Fusion Science, Toki 509-5292 (Japan); Vela, L. [Physics Department, Universidad Carlos III de Madrid, Avda de la Universidad 30, 28911-Leganés, Madrid (Spain)

    2014-03-15

    Three-dimensional global drift fluid simulations are carried out to analyze coherent plasma structures appearing in the NAGDIS-II linear device (nagoya divertor plasma Simulator-II). The numerical simulations reproduce several features of the intermittent spiraling structures observed, for instance, statistical properties, rotation frequency, and the frequency of plasma expulsion. The detailed inspection of the three-dimensional plasma dynamics allows to identify the key mechanism behind the formation of these intermittent events. The resistive coupling between electron pressure and parallel electric field in the plasma source region gives rise to a quasilinear predator-prey like dynamics where the axisymmetric mode represents the prey and the spiraling structure with low azimuthal mode number represents the predator. This interpretation is confirmed by a reduced one-dimensional quasilinear model derived on the basis of the findings in the full three-dimensional simulations. The dominant dynamics reveals certain similarities to the classical Lotka-Volterra cycle.

  11. A plasma source driven predator-prey like mechanism as a potential cause of spiraling intermittencies in linear plasma devices

    Science.gov (United States)

    Reiser, D.; Ohno, N.; Tanaka, H.; Vela, L.

    2014-03-01

    Three-dimensional global drift fluid simulations are carried out to analyze coherent plasma structures appearing in the NAGDIS-II linear device (nagoya divertor plasma Simulator-II). The numerical simulations reproduce several features of the intermittent spiraling structures observed, for instance, statistical properties, rotation frequency, and the frequency of plasma expulsion. The detailed inspection of the three-dimensional plasma dynamics allows to identify the key mechanism behind the formation of these intermittent events. The resistive coupling between electron pressure and parallel electric field in the plasma source region gives rise to a quasilinear predator-prey like dynamics where the axisymmetric mode represents the prey and the spiraling structure with low azimuthal mode number represents the predator. This interpretation is confirmed by a reduced one-dimensional quasilinear model derived on the basis of the findings in the full three-dimensional simulations. The dominant dynamics reveals certain similarities to the classical Lotka-Volterra cycle.

  12. Effect of turbulence on the dissipation of the space-charge wave in a bounded turbulent plasma column

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Myoung-Jae [Department of Physics and Research Institute for Natural Sciences, Hanyang University, Seoul 04763 (Korea, Republic of); Jung, Young-Dae, E-mail: ydjung@hanyang.ac.kr [Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180-3590 (United States); Department of Applied Physics and Department of Bionanotechnology, Hanyang University, Ansan, Kyunggi-Do 15588 (Korea, Republic of)

    2016-07-15

    The dispersion relation and the dissipation process of the space-charge wave propagating in a bounded plasma such as a cylindrical waveguide are investigated by employing the longitudinal dielectric permittivity that contains the diffusivity based on the Dupree theory of turbulent plasma. We derived the dispersion relation for space-charge wave in terms of the radius of cylindrical waveguide and the roots of the Bessel function of the first kind which appears as the boundary condition. We find that the wave frequency for a lower-order root of the Bessel function is higher than that of a higher-order root. We also find that the dissipation is greatest for the lowest-order root, but it is suppressed significantly as the order of the root increases. The wave frequency and the dissipation process are enhanced as the radius of cylindrical waveguide increases. However, they are always smaller than the case of bulk plasma. We find that the diffusivity of turbulent plasma would enhance the damping of space-charge waves, especially, in the range of small wave number. For a large wave number, the diffusivity has little effect on the damping.

  13. On Variable Geometric Factor Systems for Top-Hat Electrostatic Space Plasma Analyzers

    Science.gov (United States)

    Kataria, Dhiren O.; Collinson, Glyn A.

    2010-01-01

    Even in the relatively small region of space that is the Earth's magnetosphere, ion and electron fluxes can vary by several orders of magnitude. Top-hat electrostatic analyzers currently do not possess the dynamic range required to sample plasma under all conditions. The purpose of this study was to compare, through computer simulation, three new electrostatic methods that would allow the sensitivity of a sensor to be varied through control of its geometric factor (GF) (much like an aperture on a camera). The methods studied were inner filter plates, split hemispherical analyzer (SHA) and top-cap electrode. This is the first discussion of the filter plate concept and also the first study where all three systems are studied within a common analyzer design, so that their relative merits could be fairly compared. Filter plates were found to have the important advantage that they facilitate the reduction in instrument sensitivity whilst keeping all other instrument parameters constant. However, it was discovered that filter plates have numerous disadvantages that make such a system impracticable for a top-hat electrostatic analyzer. It was found that both the top-cap electrode and SHA are promising variable geometric factor system (VGFS) concepts for implementation into a top-hat electrostatic analyzer, each with distinct advantages over the other.

  14. Multiple Hollow Cathode Wear Testing for the Space Station Plasma Contactor

    Science.gov (United States)

    Soulas, George C.

    1994-01-01

    A wear test of four hollow cathodes was conducted to resolve issues associated with the Space Station plasma contactor. The objectives of this test were to evaluate unit-to-unit dispersions, verify the transportability of contamination control protocols developed by the project, and to evaluate cathode contamination control and activation procedures to enable simplification of the gas feed system and heater power processor. These objectives were achieved by wear testing four cathodes concurrently to 2000 hours. Test results showed maximum unit-to-unit deviations for discharge voltages and cathode tip temperatures to be +/-3 percent and +/-2 percent, respectively, of the nominal values. Cathodes utilizing contamination control procedures known to increase cathode lifetime showed no trends in their monitored parameters that would indicate a possible failure, demonstrating that contamination control procedures had been successfully transferred. Comparisons of cathodes utilizing and not utilizing a purifier or simplified activation procedure showed similar behavior during wear testing and pre- and post-test performance characterizations. This behavior indicates that use of simplified cathode systems and procedures is consistent with long cathode lifetimes.

  15. The potential of rapid cooling spark plasma sintering for metallic materials

    Directory of Open Access Journals (Sweden)

    Faming Zhang

    2013-05-01

    Full Text Available Spark plasma sintering (SPS is a remarkable technique for consolidating a large variety of advanced materials with rapid heating rates. However, adjusting the cooling rates has so far faced limitations. This communication discusses the potentials of SPS integrated with a novel gas quenching system that can allow metallic materials to be sintered and rapidly quenched directly after the sintering step, saving energy and costs. Results on numerical simulations of rapid cooling-SPS and the mechanical properties and microstructures of Ti6Al4V alloy are discussed; exhibiting the feasibility of this rapid cooling SPS technique and the major implications for the field of SPS and metallic powder consolidation.

  16. Characteristics of the NASA Lewis bumpy torus plasma generated with high positive or negative applied potentials

    Science.gov (United States)

    Roth, J. R.; Gerdin, G. A.

    1976-01-01

    The toroidal ring of plasma contained in the NASA Lewis bumpy-torus superconducting magnet facility may be biased to positive or negative potentials approaching 50 kilovolts by applying direct-current voltages of the respective polarity to 12 or fewer of the midplane electrode rings. The electric fields which are responsible for heating the ions by E/B drift then point radially outward or inward. The low-frequency fluctuations below the ion cyclotron frequency appeared to be dominated by rotating spokes.

  17. The potential role of curcumin (diferuloylmethane in plasma cell dyscrasias/paraproteinemia

    Directory of Open Access Journals (Sweden)

    Terry Golombick

    2008-03-01

    Full Text Available Terry Golombick, Terry DiamondDepartment of Endocrinology, St George Hospital, Kogarah, AustraliaAbstract: Plasma cell dyscrasias, most commonly associated with paraproteinemia, are a diverse group of diseases. Monoclonal gammopathy of undefined significance (MGUS can precede multiple myeloma, a progressive neoplastic disease. MGUS occurs in association with a variety of other diseases and currently no treatment is recommended but rather “watchful waiting”. Given that the size of the M-protein is a risk factor for disease progression, early intervention with the aim of reducing the paraprotein load would provide an innovative therapeutic tool. Preliminary results from our pilot study show a drop of between 5% and 30% serum paraprotein in patients taking curcumin compared with patients on placebo. Curcumin is a diferuloylmethane present in extracts of the rhizome of the Curcuma longa plant. As a natural product, this has exciting potential in the treatment of plasma cell dyscrasias.Keywords: plasma cell dyscrasias, MGUS, myeloma, curcumin, paraproteinemia

  18. Potential applications of nonthermal plasmas against biofilm-associated micro-organisms in vitro.

    Science.gov (United States)

    Puligundla, P; Mok, C

    2017-01-20

    Biofilms as complex microbial communities attached to surfaces pose several challenges in different sectors, ranging from food and healthcare to desalination and power generation. The biofilm mode of growth allows microorganisms to survive in hostile environments and biofilm cells exhibit distinct physiology and behaviour in comparison with their planktonic counterparts. They are ubiquitous, resilient and difficult to eradicate due to their resistant phenotype. Several chemical-based cleaning and disinfection regimens are conventionally used against biofilm-dwelling micro-organisms in vitro. Although such approaches are generally considered to be effective, they may contribute to the dissemination of antimicrobial resistance and environmental pollution. Consequently, advanced green technologies for biofilm control are constantly emerging. Disinfection using nonthermal plasmas (NTPs) is one of the novel strategies having a great potential for control of biofilms of a broad spectrum of micro-organisms. This review discusses several aspects related to the inactivation of biofilm-associated bacteria and fungi by different types of NTPs under in vitro conditions. A brief introduction summarizes prevailing methods in biofilm inactivation, followed by introduction to gas discharge plasmas, active plasma species and their inactivating mechanism. Subsequently, significance and aspects of NTP inactivation of biofilm-associated bacteria, especially those of medical importance, including opportunistic pathogens, oral pathogenic bacteria, foodborne pathogens and implant bacteria, are discussed. The remainder of the review discusses majorly about the synergistic effect of NTPs and their activity against biofilm-associated fungi, especially Candida species.

  19. MicroRNAs in plasma and cerebrospinal fluid as potential markers for Alzheimer's disease.

    Science.gov (United States)

    Kiko, Takehiro; Nakagawa, Kiyotaka; Tsuduki, Tsuyoshi; Furukawa, Katsutoshi; Arai, Hiroyuki; Miyazawa, Teruo

    2014-01-01

    The development of Alzheimer's disease (AD) biomarkers remains an unmet challenge, and new approaches that can improve current AD biomarker strategies are needed. Recent reports suggested that microRNA (miRNA) profiling of biological fluids has emerged as a diagnostic tool for several pathologic conditions. In this study, we measured six candidate miRNAs (miR-9, miR-29a, miR-29b, miR-34a, miR-125b, and miR-146a) in plasma and cerebrospinal fluid (CSF) of AD and normal subjects by using quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) to evaluate their potential usability as AD biomarkers. The qRT-PCR results showed that plasma miR-34a and miR-146a levels, and CSF miR-34a, miR-125b, and miR-146a levels in AD patients were significantly lower than in control subjects. On the other hand, CSF miR-29a and miR-29b levels were significantly higher than in control subjects. Our results provide a possibility that miRNAs detected in plasma and CSF can serve as biomarkers for AD.

  20. Heavy ion beam probing—diagnostics to study potential and turbulence in toroidal plasmas

    Science.gov (United States)

    Melnikov, A. V.; Krupnik, L. I.; Eliseev, L. G.; Barcala, J. M.; Bravo, A.; Chmyga, A. A.; Deshko, G. N.; Drabinskij, M. A.; Hidalgo, C.; Khabanov, P. O.; Khrebtov, S. M.; Kharchev, N. K.; Komarov, A. D.; Kozachek, A. S.; Lopez, J.; Lysenko, S. E.; Martin, G.; Molinero, A.; de Pablos, J. L.; Soleto, A.; Ufimtsev, M. V.; Zenin, V. N.; Zhezhera, A. I.; T-10 Team; TJ-II Team

    2017-07-01

    Heavy ion beam probing (HIBP) is a unique diagnostics to study the core plasma potential and turbulence. Advanced HIBPs operate in the T-10 tokamak and TJ-II flexible heliac with fine focused (magnetic configurations with ECR and neutral beam injection (NBI) heating at TJ-II. Time evolution of the radial profiles and/or local values of plasma parameters from high field side (HFS) to low field side (LFS), -1  magnetic field B pol (by the beam toroidal shift), poloidal electric filed E pol that allows one to derive the electrostatic turbulent particle flux ΓE×B. The cross-phase of density oscillations produces the phase velocity of their poloidal propagation or rotation; also it gives the poloidal mode number. Dual HIBP, consisting of two identical HIBPs located ¼ torus apart provide the long-range correlations of core plasma parameters. Low-noise high-gain electronics allows us to study broadband turbulence and quasi-coherent modes like geodesic acoustic modes and Alfvén eigenmodes.

  1. Effect of Bohm quantum potential in the propagation of ion-acoustic waves in degenerate plasmas

    Science.gov (United States)

    Hasan, M. M.; Hossen, M. A.; Rafat, A.; Mamun, A. A.

    2016-10-01

    A theoretical investigation has been carried out on the propagation of the ion-acoustic (IA) waves in a relativistic degenerate plasma containing relativistic degenerate electron and positron fluids in the presence of inertial non-relativistic light ion fluid. The Korteweg-de Vries (K-dV), modified K-dV (mK-dV), and mixed mK-dV (mmK-dV) equations are derived by adopting the reductive perturbation method. In order to analyze the basic features (phase speed, amplitude, width, etc.) of the IA solitary waves (SWs), the SWs solutions of the K-dV, mK-dV, and mmK-dV are numerically analyzed. It is found that the degenerate pressure, inclusion of the new phenomena like the Fermi temperatures and quantum mechanical effects (arising due to the quantum diffraction) of both electrons and positrons, number densities, etc., of the plasma species remarkably change the basic characteristics of the IA SWs which are found to be formed either with positive or negative potential. The implication of our results in explaining different nonlinear phenomena in astrophysical compact objects, e.g., white dwarfs, neutron stars, etc., and laboratory plasmas like intense laser-solid matter interaction experiments, etc., are mentioned.

  2. The transport of phosphate between the plasma and dialysate compartments in peritoneal dialysis is influenced by an electric potential difference

    DEFF Research Database (Denmark)

    Graff, J; Fugleberg, S; Brahm, J

    1996-01-01

    was not identifiable. Furthermore, it was demonstrated that the electrochemical gradient between plasma water and dialysate favours the diffusive phosphate transport, and both electric and chemical potentials must be taken into account in calculations of the transperitoneal phosphate transport....

  3. Operational Status of the International Space Station Plasma Contactor Hollow Cathode Assemblies July 2001 to May 2013

    Science.gov (United States)

    Kamhawi, Hani; Yim, John T.; Patterson, Michael J.; Dalton, Penni J.

    2013-01-01

    The International Space Station has onboard two Aerojet Rocketdyne developed plasma contactor units that perform the function of charge control. The plasma contactor units contain NASA Glenn Research Center developed hollow cathode assemblies. NASA Glenn Research Center monitors the on-orbit operation of the flight hollow cathode assemblies. As of May 31, 2013, HCA.001-F has been ignited and operated 123 times and has accumulated 8072 hours of operation, whereas, HCA.003-F has been ignited and operated 112 times and has accumulated 9664 hours of operation. Monitored hollow cathode ignition times and anode voltage magnitudes indicate that they continue to operate nominally.

  4. Operational Status of the International Space Station Plasma Contactor Hollow Cathode Assemblies from July 2011 to May 2013

    Science.gov (United States)

    Kamhawi, Hani; Yim, John T.; Patterson, Michael J.; Dalton, Penni J.

    2014-01-01

    The International Space Station has onboard two Aerojet Rocketdyne developed plasma contactor units that perform the function of charge control. The plasma contactor units contain NASA Glenn Research Center developed hollow cathode assemblies. NASA Glenn Research Center monitors the onorbit operation of the flight hollow cathode assemblies. As of May 31, 2013, HCA.001-F has been ignited and operated 123 times and has accumulated 8072 hours of operation, whereas, HCA.003-F has been ignited and operated 112 times and has accumulated 9664 hours of operation. Monitored hollow cathode ignition times and anode voltage magnitudes indicate that they continue to operate nominally.

  5. Asymptotic Behavior for a Class of Modified α-Potentials in a Half Space

    Directory of Open Access Journals (Sweden)

    Lei Qiao

    2010-01-01

    Full Text Available A class of α-potentials represented as the sum of modified Green potential and modified Poisson integral are proved to have the growth estimates Rα,l,l(x=o(xnβ|x|l−2β+2h(|x|−1 at infinity in the upper-half space of the n-dimensional Euclidean space, where the function h(|x| is a positive non-decreasing function on the interval (0,∞ satisfying certain conditions. This result generalizes the growth properties of analytic functions, harmonic functions, and superharmonic functions.

  6. Representation of distributions by harmonic and monogenic potentials in Euclidean space

    OpenAIRE

    Brackx, Fred; De Bie, Hendrik; De Schepper, Hennie

    2015-01-01

    In the framework of Clifford analysis, a chain of harmonic and monogenic potentials in the upper half of Euclidean space $R^{m+1}_+$ was recently constructed, including a higher dimensional analogue of the logarithmic function in the complex plane, and their distributional boundary values were computed. In this paper we determine these potentials in lower half-space $R^{m+1}_-$ and investigate whether they can be extended through the boundary $R^m$. This is a stepping stone to the representat...

  7. Analytic Solutions of the Schamel-KdV Equation by Using Different Methods: Application to a Dusty Space Plasma

    Directory of Open Access Journals (Sweden)

    Orhan DÖNMEZ

    2016-12-01

    Full Text Available The wave properties in a dusty space plasma consisting of positively and negatively charged  dust as well as distributed nonisothermal electrons are investigated by using the exact traveling wave solutions of the Schamel-KdV equation. The analytic solutions are obtained by the  different types $(G'/G$-expansion methods and direct integration. The nonlinear dynamics of ion-acoustic waves for the various values of phase speed $V_p$, plasma parameters  $\\alpha$, $\\sigma$, and $\\sigma_d$,  and the source term $\\mu$ are studied. We have observed different types of waves from the different analytic solutions obtained from the different methods. Consequently, we have found the discontinuity, shock or solitary waves. It is also concluded  that these parameters play an important role in the presence of solitary waves inside the plasma. Depending on plasma parameters, the discontinuity wave turns  into solitary wave solution for the  certain values of the phase speed and plasma parameters. Additionally, exact solutions of  the Schamel-KdV equation may also be used to understand the wave types and properties in the different plasma systems.

  8. New-Measurement Techniques to Diagnose Charged Dust and Plasma Layers in the Near-Earth Space Environment Using Ground-Based Ionospheric Heating Facilities

    OpenAIRE

    Mahmoudian, Alireza

    2013-01-01

    Recently, experimental observations have shown that radar echoes from the irregularitysource region associated with mesospheric dusty space plasmas may be modulated by radio wave heating with ground-based ionospheric heating facilities. These experiments show great promise as a diagnostic for the associated dusty plasma in the Near-Earth Space Environment which is believed to have links to global change. This provides an alternative to more complicated and costly space-based observational app...

  9. Integration of the Belarusian Space Research Potential Into International University Nanosatellite Programm

    Science.gov (United States)

    Saetchnikov, Vladimir; Ablameyko, Sergey; Ponariadov, Vladimir

    Belarus has inherited a significant space research potential created back in the Soviet era. It is one of the countries in the world capable of research, engineering and production across a wide range of space technologies, such as remote sensing systems, satellite telecommunication systems and positioning systems etc. Despite these strengths, the participation of Belarusian space organizations in the UN space activity and International research programs is very low. Belarusian State University (BSU) is the leading research and high school education organization of Belarus in several fields of research and development. It was deeply involved into various space research projects, including Soviet Lunar Program, Space Station “Mir”, Space Shuttle “Buran”. From 2004, when the national space programs were restarted, branches of BSU like Institute of Physics and Aerospace Technologies (IPAT), Center for aerospace education, Research laboratory of applied space technologies are leading the research and development works in the field of space communication systems, Earth observation tools and technologies, electronic and optic sensors, etc. The mail fields of activity are: • Hard and software development for small satellites and university satellites in particular. • Development of sensor satellite systems. • Small satellite research experiments (biological and medical in particular). • Earth, airplane and satellite remote monitoring systems including hard and software. • Early warning ecological and industrial Systems. • Geographic information systems of several natural and industrial areas. • Climate change investigation. We have partners from several universities and research institutes from Russian Federation, Ukraine, Kazakhstan and Germany etc. We have a ground station to receive satellite data in RF L and X bands and are very interested to be incorporated into international remote monitoring network. This activity can be combined with

  10. Chromium(VI)-induced Production of Reactive Oxygen Species, Change of Plasma Membrane Potential and Dissipation of Mitochondria Membrane Potential in Chinese Hamster Lung Cell Cultures

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Objective To examine whether Reactive Oxygen Species (ROS) is generated, and whether plasma membrane potential and mitochondrial membrane potential are depolarized in Chinese Hamster Lung (CHL) cell lines exposed to Cr (VI). Methods CHL cells were incubated with Cr(VI) at 10 μmol/L, 2.5 μmol/L, 0.65 μmol/L for 3 and 6 hours, respectively. The production of ROS was performed by using 2,7_dichlorofluorescin diacetate; The changes in plasma membrane potential were estimated using fluorescent cationic dye DiBAC4; And the changes in mitochondria membrane potential were estimated using fluorescent dye Rhodamine 123. Results The ROS levels in CHL cells increased in all treated groups compared with the control group (P<0.01); The plasma membrane potential and mitochondrial membrane potential in CHL cells dissipated after incubated with Cr(VI) at 10 μmol/L for 3 hours and 6 hours (P<0.01), at 2.5 μmol/L for 6 hours (P<0.01 or 0.05). Conclusion Cr(VI) causes the dissipation of plasma membrane potential and mitochondrial membrane potential in CHL cell cultures, and Cr(VI)_induced ROS may play a role in the injuries.

  11. Hydrogen Plasma Reduction of Lunar Regolith for In-Space Fabrication Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Tools for extracting resources from the moon are needed to support future space missions. Of particular interest is the production of raw materials for in-space...

  12. Structured methods for identifying and correcting potential human errors in space operations.

    Science.gov (United States)

    Nelson, W R; Haney, L N; Ostrom, L T; Richards, R E

    1998-01-01

    Human performance plays a significant role in the development and operation of any complex system, and human errors are significant contributors to degraded performance, incidents, and accidents for technologies as diverse as medical systems, commercial aircraft, offshore oil platforms, nuclear power plants, and space systems. To date, serious accidents attributed to human error have fortunately been rare in space operations. However, as flight rates go up and the duration of space missions increases, the accident rate could increase unless proactive action is taken to identity and correct potential human errors in space operations. The Idaho National Engineering and Environmental Laboratory (INEEL) has developed and applied structured methods of human error analysis to identify potential human errors, assess their effects on system performance, and develop strategies to prevent the errors or mitigate their consequences. These methods are being applied in NASA-sponsored programs to the domain of commercial aviation, focusing on airplane maintenance and air traffic management. The application of human error analysis to space operations could contribute to minimize the risks associated with human error in the design and operation of future space systems.

  13. Low-gravity Orbiting Research Laboratory Environment Potential Impact on Space Biology Research

    Science.gov (United States)

    Jules, Kenol

    2006-01-01

    One of the major objectives of any orbital space research platform is to provide a quiescent low gravity, preferably a zero gravity environment, to perform fundamental as well as applied research. However, small disturbances exist onboard any low earth orbital research platform. The impact of these disturbances must be taken into account by space research scientists during their research planning, design and data analysis in order to avoid confounding factors in their science results. The reduced gravity environment of an orbiting research platform in low earth orbit is a complex phenomenon. Many factors, among others, such as experiment operations, equipment operation, life support systems and crew activity (if it is a crewed platform), aerodynamic drag, gravity gradient, rotational effects as well as the vehicle structural resonance frequencies (structural modes) contribute to form the overall reduced gravity environment in which space research is performed. The contribution of these small disturbances or accelerations is precisely why the environment is NOT a zero gravity environment, but a reduced acceleration environment. This paper does not discuss other factors such as radiation, electromagnetic interference, thermal and pressure gradient changes, acoustic and CO2 build-up to name a few that affect the space research environment as well, but it focuses solely on the magnitude of the acceleration level found on orbiting research laboratory used by research scientists to conduct space research. For ease of analysis this paper divides the frequency spectrum relevant to most of the space research disciplines into three regimes: a) quasi-steady, b) vibratory and c) transient. The International Space Station is used as an example to illustrate the point. The paper discusses the impact of these three regimes on space biology research and results from space flown experiments are used to illustrate the potential negative impact of these disturbances (accelerations

  14. Global symplectic potentials on the Witten covariant phase space for bosonic extendons

    CERN Document Server

    Cartas-Fuentevilla, R

    2002-01-01

    It is proved that the projections of the deformation vector field, normal and tangential to the worldsheet manifold swept out by Dirac-Nambu-Goto bosonic extendons propagating in a curved background, play the role of {\\it global} symplectic potentials on the corresponding Witten covariant phase space. It is also proved that the {\\it presymplectic} structure obtained from such potentials by direct exterior derivation, has not components tangent to the action of the relevant diffeomorphisms group of the theory.

  15. Metric-space approach to potentials and its relevance to density-functional theory

    Science.gov (United States)

    Sharp, P. M.; D'Amico, I.

    2016-12-01

    External potentials play a crucial role in modeling quantum systems, since, for a given interparticle interaction, they define the system Hamiltonian. We use the metric-space approach to quantum mechanics to derive, from the energy conservation law, two natural metrics for potentials. We show that these metrics are well defined for physical potentials, regardless of whether the system is in an eigenstate or if the potential is bounded. In addition, we discuss the gauge freedom of potentials and how to ensure that the metrics preserve physical relevance. Our metrics for potentials, together with the metrics for wave functions and densities from I. D'Amico et al. [Phys. Rev. Lett. 106, 050401 (2011), 10.1103/PhysRevLett.106.050401] paves the way for a comprehensive study of the two fundamental theorems of density-functional theory. We explore these by analyzing two many-body systems for which the related exact Kohn-Sham systems can be derived. First we consider the information provided by each of the metrics, and we find that the density metric performs best in distinguishing two many-body systems. Next we study for the systems at hand the one-to-one relationships among potentials, ground-state wave functions, and ground-state densities defined by the Hohenberg-Kohn theorem as relationships in metric spaces. We find that, in metric space, these relationships are monotonic and incorporate regions of linearity, at least for the systems considered. Finally, we use the metrics for wave functions and potentials in order to assess quantitatively how close the many-body and Kohn-Sham systems are: We show that, at least for the systems analyzed, both metrics provide a consistent picture, and for large regions of the parameter space the error in approximating the many-body wave function with the Kohn-Sham wave function lies under a threshold of 10%.

  16. The Development of Plasma Thrusters and Its Importance for Space Technology and Science Education at University of Brasilia

    Science.gov (United States)

    Ferreira, Jose Leonardo; Calvoso, Lui; Gessini, Paolo; Ferreira, Ivan

    Since 2004 The Plasma Physics Laboratory of University of Brasilia (Brazil) is developing Hall Plasma Thurusters for Satellite station keeping and orbit control. The project is supported by CNPq, CAPES, FAP DF and from The Brazillian Space Agency-AEB. The project is part of The UNIESPAÇO Program for Space Activities Development in Brazillian Universities. In this work we are going to present the highlights of this project together with its vital contribution to include University of Brasilia in the Brazillian Space Program. Electric propulsion has already shown, over the years, its great advantages in being used as main and secondary thruster system of several space mission types. Between the many thruster concepts, one that has more tradition in flying real spacecraft is the Hall Effect Thruster (HET). These thrusters, first developed by the USSR in the 1960s, uses, in the traditional design, the radial magnetic field and axial electric field to trap electrons, ionize the gas and accelerate the plasma to therefore generate thrust. In contrast to the usual solution of using electromagnets to generate the magnetic field, the research group of the Plasma Physics Laboratory of University of Brasília has been working to develop new models of HETs that uses combined permanent magnets to generate the necessary magnetic field, with the main objective of saving electric power in the final system design. Since the beginning of this research line it was developed and implemented two prototypes of the Permanent Magnet Hall Thruster (PMHT). The first prototype, called P-HALL1, was successfully tested with the using of many diagnostics instruments, including, RF probe, Langmuir probe, Ion collector and Ion energy analyzer. The second prototype, P-HALL2, is currently under testing, and it’s planned the increasing of the plasma diagnostics and technology analysis, with the inclusion of a thrust balance, mass spectroscopy and Doppler broadening. We are also developing an

  17. Ion beam treatment of potential space materials at the NASA Lewis Research Center

    Science.gov (United States)

    Kussmaul, Michael; Mirtich, Michael J.; Curren, Arthur

    1992-01-01

    Ion source systems in different configurations, have been used to generate unique morphologies for several NASA space applications. The discharge chamber of a 30 cm ion source was successfully used to texture potential space radiator materials for the purpose of obtaining values of thermal emittance greater than 0.85 at 700 and 900 K. High absorptance surfaces were obtained using ion beam seed texturing, for space radiator materials that were flown on the Long Duration Exposure Facility (LDEF) for 5.8 years in space. An ion source discharge chamber was also used to develop electrode surfaces with suppressed secondary electron emission characteristics for use in collectors in microwave amplifier traveling wave tubes. This was accomplished by sputtering textured carbon onto copper as well as texturing copper using tantalum and molybdenum as sacrificial texture inducing seeding materials. In a third configuration, a dual ion beam system was used to generate high transmittance diamondlike carbon (DLC) films.

  18. On the Riesz Potential and Its Commutators on Generalized Orlicz-Morrey Spaces

    Directory of Open Access Journals (Sweden)

    Vagif S. Guliyev

    2014-01-01

    Full Text Available We consider generalized Orlicz-Morrey spaces MΦ,φ(ℝn including their weak versions WMΦ,φ(ℝn. In these spaces we prove the boundedness of the Riesz potential from MΦ,φ1(ℝn to MΨ,φ2(ℝn and from MΦ,φ1(ℝn to WMΨ,φ2(ℝn. As applications of those results, the boundedness of the commutators of the Riesz potential on generalized Orlicz-Morrey space is also obtained. In all the cases the conditions for the boundedness are given either in terms of Zygmund-type integral inequalities on (φ1,φ2, which do not assume any assumption on monotonicity of φ1(x,r, φ2(x,r in r.

  19. Near-Space Microwave Radar Remote Sensing: Potentials and Challenge Analysis

    Directory of Open Access Journals (Sweden)

    Qicong Peng

    2010-03-01

    Full Text Available Near-space, defined as the region between 20 km and 100 km, offers many new capabilities that are not accessible to low earth orbit (LEO satellites and airplanes, because it is above storm and not constrained by either the orbital mechanics of satellites or the high fuel consumption of airplanes. By placing radar transmitter/receiver in near-space platforms, many functions that are currently performed with satellites or airplanes could be performed in a cheaper way. Inspired by these advantages, this paper introduces several near-space vehicle-based radar configurations, such as near-space passive bistatic radar and high-resolution wide-swath (HRWS synthetic aperture radar (SAR. Their potential applications, technical challenges and possible solutions are investigated. It is shown that near-space is a satisfactory solution to some specific remote sensing applications. Firstly, near-space passive bistatic radar using opportunistic illuminators offers a solution to persistent regional remote sensing, which is particularly interest for protecting homeland security or monitoring regional environment. Secondly, near-space provides an optimal solution to relative HRWS SAR imaging. Moreover, as motion compensation is a common technical challenge for the described radars, an active transponder-based motion compensation is also described.

  20. Acceleration of a Particle-in-Cell Code for Space Plasma Simulations with OpenACC

    Science.gov (United States)

    Peng, Ivy Bo; Markidis, Stefano; Vaivads, Andris; Vencels, Juris; Deca, Jan; Lapenta, Giovanni; Hart, Alistair; Laure, Erwin

    2015-04-01

    We simulate space plasmas with the Particle-in-cell (PIC) method that uses computational particles to mimic electrons and protons in solar wind and in Earth magnetosphere. The magnetic and electric fields are computed by solving the Maxwell's equations on a computational grid. In each PIC simulation step, there are four major phases: interpolation of fields to particles, updating the location and velocity of each particle, interpolation of particles to grids and solving the Maxwell's equations on the grid. We use the iPIC3D code, which was implemented in C++, using both MPI and OpenMP, for our case study. By November 2014, heterogeneous systems using hardware accelerators such as Graphics Processing Unit (GPUs) and the Many Integrated Core (MIC) coprocessors for high performance computing continue growth in the top 500 most powerful supercomputers world wide. Scientific applications for numerical simulations need to adapt to using accelerators to achieve portability and scalability in the coming exascale systems. In our work, we conduct a case study of using OpenACC to offload the computation intensive parts: particle mover and interpolation of particles to grids, in a massively parallel Particle-in-Cell simulation code, iPIC3D, to multi-GPU systems. We use MPI for inter-node communication for halo exchange and communicating particles. We identify the most promising parts suitable for GPUs accelerator by profiling using CrayPAT. We implemented manual deep copy to address the challenges of porting C++ classes to GPU. We document the necessary changes in the exiting algorithms to adapt for GPU computation. We present the challenges and findings as well as our methodology for porting a Particle-in-Cell code to multi-GPU systems using OpenACC. In this work, we will present the challenges, findings and our methodology of porting a Particle-in-Cell code for space applications as follows: We profile the iPIC3D code by Cray Performance Analysis Tool (CrayPAT) and identify

  1. Solving kinetic equations with adaptive mesh in phase space for rarefied gas dynamics and plasma physics (Invited)

    Energy Technology Data Exchange (ETDEWEB)

    Kolobov, Vladimir [CFD Research Corporation, Huntsville, AL 35805, USA and The University of Alabama in Huntsville, Huntsville, AL 35805 (United States); Arslanbekov, Robert [CFD Research Corporation, Huntsville, AL 35805 (United States); Frolova, Anna [Computing Center of the Russian Academy of Sciences, Moscow, 119333 (Russian Federation)

    2014-12-09

    The paper describes an Adaptive Mesh in Phase Space (AMPS) technique for solving kinetic equations with deterministic mesh-based methods. The AMPS technique allows automatic generation of adaptive Cartesian mesh in both physical and velocity spaces using a Tree-of-Trees data structure. We illustrate advantages of AMPS for simulations of rarefied gas dynamics and electron kinetics on low temperature plasmas. In particular, we consider formation of the velocity distribution functions in hypersonic flows, particle kinetics near oscillating boundaries, and electron kinetics in a radio-frequency sheath. AMPS provide substantial savings in computational cost and increased efficiency of the mesh-based kinetic solvers.

  2. A Fractional Differential Kinetic Equation and Applications to Modelling Bursts in Turbulent Nonlinear Space Plasmas

    Science.gov (United States)

    Watkins, N. W.; Rosenberg, S.; Sanchez, R.; Chapman, S. C.; Credgington, D.

    2008-12-01

    Since the 1960s Mandelbrot has advocated the use of fractals for the description of the non-Euclidean geometry of many aspects of nature. In particular he proposed two kinds of model to capture persistence in time (his Joseph effect, common in hydrology and with fractional Brownian motion as the prototype) and/or prone to heavy tailed jumps (the Noah effect, typical of economic indices, for which he proposed Lévy flights as an exemplar). Both effects are now well demonstrated in space plasmas, notably in the turbulent solar wind. Models have, however, typically emphasised one of the Noah and Joseph parameters (the Lévy exponent μ and the temporal exponent β) at the other's expense. I will describe recent work in which we studied a simple self-affine stable model-linear fractional stable motion, LFSM, which unifies both effects and present a recently-derived diffusion equation for LFSM. This replaces the second order spatial derivative in the equation of fBm with a fractional derivative of order μ, but retains a diffusion coefficient with a power law time dependence rather than a fractional derivative in time. I will also show work in progress using an LFSM model and simple analytic scaling arguments to study the problem of the area between an LFSM curve and a threshold. This problem relates to the burst size measure introduced by Takalo and Consolini into solar-terrestrial physics and further studied by Freeman et al [PRE, 2000] on solar wind Poynting flux near L1. We test how expressions derived by other authors generalise to the non-Gaussian, constant threshold problem. Ongoing work on extension of these LFSM results to multifractals will also be discussed.

  3. Plasma membranes modified by plasma treatment or deposition as solid electrolytes for potential application in solid alkaline fuel cells.

    Science.gov (United States)

    Reinholdt, Marc; Ilie, Alina; Roualdès, Stéphanie; Frugier, Jérémy; Schieda, Mauricio; Coutanceau, Christophe; Martemianov, Serguei; Flaud, Valérie; Beche, Eric; Durand, Jean

    2012-07-30

    In the highly competitive market of fuel cells, solid alkaline fuel cells using liquid fuel (such as cheap, non-toxic and non-valorized glycerol) and not requiring noble metal as catalyst seem quite promising. One of the main hurdles for emergence of such a technology is the development of a hydroxide-conducting membrane characterized by both high conductivity and low fuel permeability. Plasma treatments can enable to positively tune the main fuel cell membrane requirements. In this work, commercial ADP-Morgane® fluorinated polymer membranes and a new brand of cross-linked poly(aryl-ether) polymer membranes, named AMELI-32®, both containing quaternary ammonium functionalities, have been modified by argon plasma treatment or triallylamine-based plasma deposit. Under the concomitant etching/cross-linking/oxidation effects inherent to the plasma modification, transport properties (ionic exchange capacity, water uptake, ionic conductivity and fuel retention) of membranes have been improved. Consequently, using plasma modified ADP-Morgane® membrane as electrolyte in a solid alkaline fuel cell operating with glycerol as fuel has allowed increasing the maximum power density by a factor 3 when compared to the untreated membrane.

  4. Plasma Membranes Modified by Plasma Treatment or Deposition as Solid Electrolytes for Potential Application in Solid Alkaline Fuel Cells

    Directory of Open Access Journals (Sweden)

    Christophe Coutanceau

    2012-07-01

    Full Text Available In the highly competitive market of fuel cells, solid alkaline fuel cells using liquid fuel (such as cheap, non-toxic and non-valorized glycerol and not requiring noble metal as catalyst seem quite promising. One of the main hurdles for emergence of such a technology is the development of a hydroxide-conducting membrane characterized by both high conductivity and low fuel permeability. Plasma treatments can enable to positively tune the main fuel cell membrane requirements. In this work, commercial ADP-Morgane® fluorinated polymer membranes and a new brand of cross-linked poly(aryl-ether polymer membranes, named AMELI-32®, both containing quaternary ammonium functionalities, have been modified by argon plasma treatment or triallylamine-based plasma deposit. Under the concomitant etching/cross-linking/oxidation effects inherent to the plasma modification, transport properties (ionic exchange capacity, water uptake, ionic conductivity and fuel retention of membranes have been improved. Consequently, using plasma modified ADP-Morgane® membrane as electrolyte in a solid alkaline fuel cell operating with glycerol as fuel has allowed increasing the maximum power density by a factor 3 when compared to the untreated membrane.

  5. The formation of relativistic plasma structures and their potential role in the generation of cosmic ray electrons

    Directory of Open Access Journals (Sweden)

    M. E. Dieckmann

    2008-11-01

    Full Text Available Recent particle-in-cell (PIC simulation studies have addressed particle acceleration and magnetic field generation in relativistic astrophysical flows by plasma phase space structures. We discuss the astrophysical environments such as the jets of compact objects, and we give an overview of the global PIC simulations of shocks. These reveal several types of phase space structures, which are relevant for the energy dissipation. These structures are typically coupled in shocks, but we choose to consider them here in an isolated form. Three structures are reviewed. (1 Simulations of interpenetrating or colliding plasma clouds can trigger filamentation instabilities, while simulations of thermally anisotropic plasmas observe the Weibel instability. Both transform a spatially uniform plasma into current filaments. These filament structures cause the growth of the magnetic fields. (2 The development of a modified two-stream instability is discussed. It saturates first by the formation of electron phase space holes. The relativistic electron clouds modulate the ion beam and a secondary, spatially localized electrostatic instability grows, which saturates by forming a relativistic ion phase space hole. It accelerates electrons to ultra-relativistic speeds. (3 A simulation is also revised, in which two clouds of an electron-ion plasma collide at the speed 0.9c. The inequal densities of both clouds and a magnetic field that is oblique to the collision velocity vector result in waves with a mixed electrostatic and electromagnetic polarity. The waves give rise to growing corkscrew distributions in the electrons and ions that establish an equipartition between the electron, the ion and the magnetic energy. The filament-, phase space hole- and corkscrew structures are discussed with respect to electron acceleration and magnetic field generation.

  6. Operation circuits of emissive probes for determination of potentials in discharge plasmas; Circuitos de operacao de sondas emissivas para a determinacao de potenciais em plasmas de descargas eletricas

    Energy Technology Data Exchange (ETDEWEB)

    Petraconi, G.; Maciel, H.S.; Borges, C. [Centro Tecnico Aeroespacial, Sao Jose dos Campos, SP (Brazil). Inst. Tecnologico de Aeronautica. Lab. de Plasmas e Processos

    1999-12-01

    In this paper two circuits for plasma potential measurement are presented. The first one is an emissive probe control circuit for fast probe characteristics reading. The second one is a differential emissive probe control circuit that adjusts the bias voltage automatically and allows a direct potential measurement. These circuits present inconveniences if the characteristic of the probe does not exhibit an ideal saturation of the current as show the results obtained in continuous current discharge and RF discharge. (author)

  7. A simulation study of interactions of space-shuttle generated electron beams with ambient plasma and neutral gas

    Science.gov (United States)

    Winglee, Robert M.

    1991-01-01

    The objective was to conduct large scale simulations of electron beams injected into space. The study of the active injection of electron beams from spacecraft is important, as it provides valuable insight into the plasma beam interactions and the development of current systems in the ionosphere. However, the beam injection itself is not simple, being constrained by the ability of the spacecraft to draw current from the ambient plasma. The generation of these return currents is dependent on several factors, including the density of the ambient plasma relative to the beam density, the presence of neutrals around the spacecraft, the configuration of the spacecraft, and the motion of the spacecraft through the plasma. Two dimensional (three velocity) particle simulations with collisional processes included are used to show how these different and often coupled processes can be used to enhance beam propagation from the spacecraft. To understand the radial expansion mechanism of an electron beam injected from a highly charged spacecraft, two dimensional particle-in-cell simulations were conducted for a high density electron beam injected parallel to magnetic fields from an isolated equipotential conductor into a cold background plasma. The simulations indicate that charge build-up at the beam stagnation point causes the beam to expand radially to the beam electron gyroradius.

  8. On the limit cycle for the 1/r^2 potential in momentum space

    CERN Document Server

    Hammer, H W; Swingle, Brian G.

    2006-01-01

    The renormalization of the attractive 1/r^2 potential has recently been studied using a variety of regulators. In particular, it was shown that renormalization with a square well in position space allows multiple solutions for the depth of the square well, including, but not requiring a renormalization group limit cycle. Here, we consider the renormalization of the 1/r^2 potential in momentum space. We regulate the problem with a momentum cutoff and absorb the cutoff dependence using a momentum-independent counterterm potential. The strength of this counterterm is uniquely determined and runs on a limit cycle. We also calculate the bound state spectrum and scattering observables, emphasizing the manifestation of the limit cycle in these observables.

  9. Phase space barriers and dividing surfaces in the absence of critical points of the potential energy

    CERN Document Server

    Ezra, Gregory S

    2010-01-01

    We consider the existence of invariant manifolds in phase space governing reaction dynamics in situations where there are no saddle points on the potential energy surface in the relevant regions of configuration space. We point out that such situations occur in a number of important classes of chemical reactions, and we illustrate this concretely by considering a model for transition state switching in an ion-molecule association reaction due to Chesnavich (J. Chem. Phys. {\\bf 84}, 2615 (1986)). For this model we show that, in the region of configuration space relevant to the reaction, there are no saddle points on the potential energy surface, but that in phase space there is a normally hyperbolic invariant manifold (NHIM) bounding a dividing surface having the property that the reactive flux through this dividing surface is a minimum. We then describe two methods for finding NHIMs and their associated phase space structures in systems with more than two degrees-of-freedom. These methods do not rely on the e...

  10. Nonlinear Electromagnetic Waves and Spherical Arc-Polarized Waves in Space Plasmas

    Science.gov (United States)

    Tsurutani, B.; Ho, Christian M.; Arballo, John K.; Lakhina, Gurbax S.; Glassmeier, Karl-Heinz; Neubauer, Fritz M.

    1997-01-01

    We review observations of nonlinear plasma waves detected by interplanetary spacecraft. For this paper we will focus primarily on the phase-steepened properties of such waves. Plasma waves at comet Giacobini-Zinner measured by the International Cometary Explorer (ICE), at comets Halley and Grigg-Skjellerup measured by Giotto, and interplanetary Alfven waves measured by Ulysses, will be discussed and intercompared.

  11. Vaccine potential of plasma bead-based dual antigen delivery system against experimental murine candidiasis.

    Science.gov (United States)

    Ahmad, Ejaj; Zia, Qamar; Fatima, Munazza Tamkeen; Owais, Mohammad; Saleemuddin, Mohammed

    2015-11-01

    The development of prophylactic anti-candidal vaccine comprising the Candida albicans cytosolic proteins (Cp) as antigen and plasma beads (PB) prepared from plasma as sustained delivery system, is described. The immune-prophylactic potential of various PBs-based dual antigen delivery systems, co-entrapping Cp pre-entrapped in PLGA microspheres were tested in the murine model. Induction of cell mediated immunity was measured by assaying DTH and NO production as well as in vitro proliferation of lymphocytes derived from the immunized animals. Expression of surface markers on APCs (CD80, CD86) and T-cells (CD4+, CD8+) was also evaluated. Humoral immune response was studied by measuring circulating anti-Cp antibodies and their subclasses. When the prophylactic efficacy of the vaccines was tested in mice challenged with virulent C. albicans, the PB-based formulation (PB-PLGA-Cp vaccine) was found to be most effective in the generation of desirable immune response, in terms of suppression of fungal load and facilitating the survival of the immunized animals.

  12. Numerical analysis of the effect of electrode spacing on deposition rate profiles in a capacitively coupled plasma reactor

    Science.gov (United States)

    Kim, Ho Jun; Lee, Hae June

    2016-12-01

    The effect of reactor dimension on deposition rate profiles is analyzed with a two-dimensional (2D) fluid simulation of a capacitively coupled plasma (CCP) reactor to deposit a hydrogenated silicon nitride (SiN x H y ) film with a SiH4/NH3/N2/He gas mixture. We focus on the complex function of electrode spacing to reveal the physical relation between reactor geometry and deposition rate profiles. The simulation demonstrates that the localization of electron density is concentrated close to the powered electrode periphery for electrode spacing of 9 mm. However, the plasma distribution becomes bulk dominated with electrode spacing of 15 mm by relaxing the localization. As a result, the increase in the electrode spacing creates a more uniform electron power density profile, and the deposition rate profile of SiN x H y film changes from convex to concave in a radial direction. The change in the deposition rate profile is validated through comparison with the experimental observation, which agrees well with the simulation results with errors of less than 5%. The deposition rate profile with electrode spacing of 9 mm is very sensitive to the non-uniform gas density condition applied to the showerhead inlet. However, the deposition rate profile with electrode spacing of 15 mm is not sensitive to the inlet gas profile because of the increasing residence time. The increase of the electrode spacing promotes molecule-molecule gas phase reactions and consequently weakens the effect of the inlet boundary condition.

  13. Statistics of magnetic field fluctuations in a partially ionized space plasma

    Energy Technology Data Exchange (ETDEWEB)

    Shaikh, Dastgeer, E-mail: dastgeer.shaikh@uah.ed [Department of Physics and Center for Space Plasma and Aeronomy Research, University of Alabama in Huntsville, Huntsville, AL 35899 (United States)

    2010-07-05

    Voyager 1 and 2 data reveals that magnetic field fluctuations are compressive and exhibit a Gaussian distribution in the compressed heliosheath plasma, whereas they follow a lognormal distribution in a nearly incompressible supersonic solar wind plasma. To describe the evolution of magnetic field, we develop a nonlinear simulation model of a partially ionized plasma based on two-dimensional time-dependent multifluid model. Our model self-consistently describes solar wind plasma ions, electrons, neutrals and pickup ions. It is found from our simulations that the magnetic field evolution is governed by mode conversion process that leads to the suppression of vortical modes, whereas the compressive modes are amplified. An implication of the mode conversion process is to quench the Alfvenic interactions associated with the vortical motions. Consequently anisotropic cascades are reduced. This is accompanied by the amplification of compressional modes that tend to isotropize the plasma fluctuations and lead to a Gaussian distribution of the magnetic field.

  14. A stress tensor eigenvector projection space for the (H2O)5 potential energy surface

    Science.gov (United States)

    Xu, Tianlv; Farrell, James; Momen, Roya; Azizi, Alireza; Kirk, Steven R.; Jenkins, Samantha; Wales, David J.

    2017-01-01

    A stress tensor eigenvector projection space is created to describe reaction pathways on the (H2O)5 MP2 potential energy surface. Evidence for the stabilizing role of the O--O bonding interactions is found from the length of the recently introduced stress tensor trajectory in the stress tensor eigenvector projection space. The stress tensor trajectories demonstrate coupling behavior of the adjoining covalent (σ) O-H and hydrogen bonds due to sharing of covalent character. Additionally, the stress tensor trajectories can show dynamic coupling effects of pairs of σ bonds and of pairs of hydrogen bonds.

  15. Controlling VUV photon fluxes in pulsed inductively coupled Ar/Cl2 plasmas and potential applications in plasma etching

    Science.gov (United States)

    Tian, Peng; Kushner, Mark J.

    2017-02-01

    UV/VUV photon fluxes in plasma materials processing have a variety of effects ranging from producing damage to stimulating synergistic reactions. Although in plasma etching processes, the rate and quality of the feature are typically controlled by the characteristics of the ion flux, to truly optimize these ion and photon driven processes, it is desirable to control the relative fluxes of ions and photons to the wafer. In prior works, it was determined that the ratio of VUV photon to ion fluxes to the substrate in low pressure inductively coupled plasmas (ICPs) sustained in rare gases can be controlled by combinations of pressure and pulse power, while the spectrum of these VUV photons can be tuned by adding additional rare gases to the plasma. In this work, VUV photon and ion fluxes are computationally investigated for Ar/Cl2 ICPs as used in etching of silicon. We found that while the overall ratio of VUV photon flux to ion flux are controlled by pressure and pulse power, by varying the fraction of Cl2 in the mixture, both the ratio of VUV to ion fluxes and the spectrum of VUV photons can be tuned. It was also found that the intensity of VUV emission from Cl(3p 44s) can be independently tuned by controlling wall surface conditions. With this ability to control ratios of ion to photon fluxes, photon stimulated processes, as observed in halogen etching of Si, can be tuned to optimize the shape of the etched features.

  16. Space Toxicology: Environmental Health Considerations during Spaceflight Operations and Potential Paths for Research

    Science.gov (United States)

    Khan-Mayberry, Noreen N.; Sundaresan, Alemalu

    2009-01-01

    Space Toxicology is a specialized discipline for spaceflight, space habitation and occupation of celestial bodies including planets, moons and asteroids [1]. Astronaut explorers face unique challenges to their health while working and living with limited resources for rescue and medical care during space operation. At its core the practice of space toxicology to identify, assess and predict potential chemical contaminants and limit the astronaut s exposure to these environmental factors in order to protect crew health. Space toxicologists are also charged with setting safe exposure limits that will protect the astronaut against a multitude of chemical exposures, in a physiologically altered state. In order to maintain sustained occupation in space, toxicological risks are gauged and managed within the context of isolation, continual exposures, reuse of air and water, limited rescue options, and the necessary use of highly toxic compounds required for propulsion. As the space program move towards human presence and exploration other celestial bodies in situ toxicological risks, such as inhalation of unusual and/or reactive mineral dusts must also be analyzed and controlled. Placing humans for long-term presence in space creates several problems and challenges to the long-term health of the crew, such as bone-loss and immunological challenges and has spurred research into acute, chronic and episodic exposure of the pulmonary system to mineral dusts [2]. NASA has demonstrated that lunar soil contains several types of reactive dusts, including an extremely fine respirable component. In order to protect astronaut health, NASA is now investigating the toxicity of this unique class of dusts. Understanding how these reactive components behave "biochemically" in a moisture-rich pulmonary environment will aid in determining how toxic these particles are to humans. The data obtained from toxicological examination of lunar dusts will determine the human risk criteria for lunar

  17. Equation of state for hot quark-gluon plasma transitions to hadrons with full QCD potential

    Science.gov (United States)

    Sheikholeslami-Sabzevari, Bijan

    2002-05-01

    A practical method based on Mayer's cluster expansion to calculate critical values for a quark-gluon plasma (QGP) phase transition to hadrons is represented. It can be applied to a high-temperature QGP for clustering of quarks to mesons and baryons. The potential used is the Cornell potential, i.e., a potential containing both confining and gluon exchange terms. Debye screening effects are included. An equation of state (EOS) for hadron production is found by analytical methods, which is valid near the critical point. The example of the formation of J/ψ and Υ is recalculated. It is shown that in the range of temperatures available by today's accelerators, the latter particles are suppressed. This is further confirmation for heavy quarkonia suppression and, hence, for a signature of a QGP. The EOS presented here also shows that in future colliders there will be no heavy quarkonia production by the mechanism of phase transition. Hence, if there will be heavy quarkonia production, it must be based on some other mechanisms, perhaps on the basis of some recently suggested possibilities.

  18. Study of plasma meniscus and beam halo in negative ion sources using three dimension in real space and three dimension in velocity space particle in cell model

    Energy Technology Data Exchange (ETDEWEB)

    Nishioka, S., E-mail: nishioka@ppl.appi.keio.ac.jp; Goto, I.; Hatayama, A. [Graduate School of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan); Miyamoto, K. [School of Natural and Living Sciences Education, Naruto University of Education, 748 Nakashima, Takashima, Naruto-cho, Naruto-shi, Tokushima 772-8502 (Japan); Okuda, S.; Fukano, A. [Toshiba, 33 Isogo-chou, Isogo-ku, Yokohama-shi, Kanagawa 235-001 (Japan)

    2014-02-15

    Our previous study by two dimension in real space and three dimension in velocity space-particle in cell model shows that the curvature of the plasma meniscus causes the beam halo in the negative ion sources. The negative ions extracted from the periphery of the meniscus are over-focused in the extractor due to the electrostatic lens effect, and consequently become the beam halo. The purpose of this study is to verify this mechanism with the full 3D model. It is shown that the above mechanism is essentially unchanged even in the 3D model, while the fraction of the beam halo is significantly reduced to 6%. This value reasonably agrees with the experimental result.

  19. Plasma Reduction of Lunar Regolith for In-Space Fabrication Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Tools for extracting resources from the moon are needed to support future space missions. Of particular interest is the production of gases and metals for life...

  20. Examining the Potential of Plasma-Assisted Pretreated Wheat Straw for Enzyme Production by Trichoderma reesei

    DEFF Research Database (Denmark)

    Rodríguez Gómez, Divanery; Lehmann, Linda Olkjær; Schultz-Jensen, Nadja

    2012-01-01

    Plasma-assisted pretreated wheat straw was investigated for cellulase and xylanase production by Trichoderma reesei fermentation. Fermentations were conducted with media containing washed and unwashed plasma-assisted pretreated wheat straw as carbon source which was sterilized by autoclavation...

  1. The Study Of Low-Frequency Instabilities Of Current Sheaths Of Space Plasma Within The Quasi-Linear Theory

    Science.gov (United States)

    Lyahov, Vladimir; Neshchadim, Vladimir

    2015-04-01

    Investigation of the stability nonelectroneutral current sheets in the linear approximation [1-4] gives information only on the initial stage of development of perturbations when their amplitudes are small. Within the framework of the quasi-linear theory one can give an answer to the question of how long the initial perturbations can grow and how change the equilibrium state of the plasma current sheet under the reverse effect of these perturbations. We derive a system of nonlinear kinetic equation with self-consistent electromagnetic field in order to study the evolution of the distribution function of the background plasma current sheet in the approximation of low-frequency eigenmodes of instabilities. Evolution equation was obtained for the perturbation of the electromagnetic field and the instability growth rate in the current sheet. Algorithms were tested for solutions of the equations obtained. 1. Lyahov V.V., Neshchadim V.M. Kinetic theory of the current sheath. I. On polarization of an equilibrium current sheath// Advances in Space Research. -2012. -Vol. 50. -P. 318-326. 2. Lyahov V.V., Neshchadim V.M. Kinetic theory of the current sheath. II. Effect of polarization on the stability of a current sheath.// Advances in Space Research.-2013. -Vol. 51. -P. 730-741. 3. Lyahov V.V., Neshchadim V.M. The Effect of Polarization on the Stability of Current Sheaths in Space Plasma // EGU General Assembly 2013, held 7-12 April, 2013 in Vienna, Austria, id. EGU2013-1379, 04/2013, Bibliographic Code: 2013EGUGA..15.1379L 4. Lyahov V.V., Neshchadim V.M. About the eguilibrium and stability of nonelectroneutral current sheats // Advances in Space Research.-2014. -Vol. 54. -P. 901-907.

  2. Active fire monitoring and fire danger potential detection from space: A review

    Institute of Scientific and Technical Information of China (English)

    John J. QU; Wanting WANG; Swarvanu DASGUPTA; Xianjun HAO

    2008-01-01

    Wildland fire is both one of the major natural hazards and a natural process for ecosystem persistence. Accurate assessment of fire danger potential and timely detection of active fires are critical for fire fighting and fuel management. Space-borne measurements have become the primary approaches for these efforts. Many research works have been conducted and some data pro-ducts have been generated for practical applications. This paper presents a review of the major sensors and algo-rithms for active fire monitoring and fire danger potential detection from space. Major sensors and their character-istics, physical principles of the major algorithms are sum-marized. Limitations of these algorithms and future improvements are also discussed.

  3. Direct Measurement of the Phase Space Ion Fluctuation Spectrum of a Laboratory Plasma Using Two Independently Tunable Lasers

    Science.gov (United States)

    Mattingly, Sean; Berumen, Jorge; Chu, Feng; Hood, Ryan; Skiff, Fred

    2013-10-01

    A novel technique for probing velocity space correlations has been developed using laser-induced fluorescence. The experiment consists of a 3 m cylindrical plasma column of singly-charged Argon ions (Ar II) with density ~ 109 cm-3 , Te ~ 5 eV , Ti ~ . 06 eV , and a 1 kG axial magnetic field. Separate metastable lines of the Ar II ions are excited using two separate narrow bandwidth lasers. The LIF response from each laser is measured through an independently moveable periscope. These periscopes may be focused on the same localized region (~ 0 . 1 cm3) or separated to view different parts of the plasma simultaneously. By adjusting these lasers independently, one may measure a correlation function as a function of the difference in measured velocities. This measurement may be repeated for different periscope positions in the plasma to obtain a two-dimensional correlation function in space and velocity difference. This correlation is directly related to the fluctuation spectrum through a Fourier transform. Measurements of these correlations are reported and discussed. NSF DOE Grant DE-FG02-99ER54543.

  4. Fundamental Study of Interactions Between Pulsed High-Density Plasmas and Materials for Space Propulsion

    Science.gov (United States)

    2016-05-23

    thermal shock and allows for optical plasma diagnostics. The new capillary uses a flash lamp approach for triggering to eliminate the need for a...add silicon oxide to alumina processing to form relatively low- melting aluminosilicate phases to enhance densification/ sintering at temperatures well...pressure on the microstructure of spark plasma sintered silicon carbide,” Journal of Chemical Processing Research 16, 303 (2007). 5. O. Sharia

  5. Plasma Membranes Modified by Plasma Treatment or Deposition as Solid Electrolytes for Potential Application in Solid Alkaline Fuel Cells

    OpenAIRE

    Christophe Coutanceau; Marc Reinholdt; Jean Durand; Valérie Flaud; Serguei Martemianov; Alina Ilie; Eric Beche; Stéphanie Roualdès; Mauricio Schieda; Jérémy Frugier

    2012-01-01

    In the highly competitive market of fuel cells, solid alkaline fuel cells using liquid fuel (such as cheap, non-toxic and non-valorized glycerol) and not requiring noble metal as catalyst seem quite promising. One of the main hurdles for emergence of such a technology is the development of a hydroxide-conducting membrane characterized by both high conductivity and low fuel permeability. Plasma treatments can enable to positively tune the main fuel cell membrane requirements. In this work, com...

  6. On the potential impact of the newly proposed quality factors on space radiation protection

    Science.gov (United States)

    Wilson, John W.; Townsend, Lawrence W.; Cucinotta, Francis A.

    1987-01-01

    The recently proposed changes in the defined quality factor hold great potential for easing some of the protection requirements from electrons and protons in the near-Earth environment. At the same time, the high Linear Energy Transfer (LET) components play an even more important role which must be further evaluated. Several recommendations are made which need to be addressed before these new quality factors can be implemented into space radiation potection practice.

  7. The Use of Langmuir Probes in Non-Maxwellian Space Plasmas

    Science.gov (United States)

    Hoegy, Walter R.; Brace, Larry H.

    1998-01-01

    Disturbance of the Maxwellian plasma may occur in the vicinity of a spacecraft due to photoemission, interactions between the spacecraft and thermospheric gases, or electron emissions from other devices on the spacecraft. Significant non-maxwellian plasma distributions may also occur in nature as a mixture of ionospheric and magnetospheric plasmas or secondaries produced by photoionization in the thermosphere or auroral precipitation. The general formulas for current collection (volt-ampere curves) by planar, cylindrical, and spherical Langmuir probes in isotropic and anisotropic non-maxwellian plasmas are examined. Examples are given of how one may identify and remove the non-maxwellian components in the Langmuir probe current to permit the ionospheric parameters to be determined. Theoretical volt-ampere curves presented for typical examples of non-maxwellian distributions include: two-temperature plasmas and a thermal plasma with an energetic electron beam. If the non-ionospheric electrons are Maxwellian at a temperature distinct from that of the ionosphere electrons, the volt-ampere curves can be fitted directly to obtain the temperatures and densities of both electron components without resorting to differenting the current. For an arbitrary isotropic distribution, the current for retarded particles is shown to be identical for the three geometries. For anisotropic distributions, the three probe geometries are not equally suited for measuring the ionospheric electron temperature and density or for determining the distribution function in the presence of non-maxwellian back-round electrons.

  8. Chemical potential and internal energy of the noninteracting Fermi gas in fractional-dimensional space

    Indian Academy of Sciences (India)

    S Panda; B K Panda

    2010-09-01

    Chemical potential and internal energy of a noninteracting Fermi gas at low temperature are evaluated using the Sommerfeld method in the fractional-dimensional space. When temperature increases, the chemical potential decreases below the Fermi energy for any dimension equal to 2 and above due to the small entropy, while it increases above the Fermi energy for dimensions below 2 as a result of high entropy. The ranges of validity of the truncated series expansions of these quantities are extended from low to intermediate temperature regime as well as from high to relatively low density regime by using the Pad ́e approximant technique.

  9. Reconstructing interaction potentials in thin films from real-space images.

    Science.gov (United States)

    Gienger, Jonas; Severin, Nikolai; Rabe, Jürgen P; Sokolov, Igor M

    2016-04-01

    We demonstrate that an inverse Monte Carlo approach allows one to reconstruct effective interaction potentials from real-space images. The method is exemplified on monomolecular ethanol-water films imaged with scanning force microscopy, which provides the spatial distribution of the molecules. Direct Monte Carlo simulations with the reconstructed potential allow for obtaining characteristics of the system which are unavailable in the experiment, such as the heat capacity of the monomolecularly thin film, and for a prediction of the critical temperature of the demixing transition.

  10. Nonperturbative renormalization group for scalar fields in de Sitter space: beyond the local potential approximation

    CERN Document Server

    Guilleux, Maxime

    2016-01-01

    Nonperturbative renormalization group techniques have recently proven a powerful tool to tackle the nontrivial infrared dynamics of light scalar fields in de Sitter space. In the present article, we develop the formalism beyond the local potential approximation employed in earlier works. In particular, we consider the derivative expansion, a systematic expansion in powers of field derivatives, appropriate for long wavelength modes, that we generalize to the relevant case of a curved metric with Lorentzian signature. The method is illustrated with a detailed discussion of the so-called local potential approximation prime which, on the top of the full effective potential, includes a running (but field-independent) field renormalization. We explicitly compute the associated anomalous dimension for O(N) theories. We find that it can take large values along the flow, leading to sizable differences as compared to the local potential approximation. However, it does not prevent the phenomenon of gravitationally induc...

  11. Performance and plasma urea nitrogen of immunocastrated males pigs of medium genetic potential

    Directory of Open Access Journals (Sweden)

    Fabiana R Caldara

    2015-05-01

    Full Text Available ABSTRACT Objective. A study was carried out to evaluate the performance and the plasma urea nitrogen (PUN of male pigs of medium genetic potential for lean meat deposition in carcass, which underwent immunocastration. Materials and methods. Forty-five seventy-days old Large White x Landrace crossbred were used. The pigs were distributed in a randomized design in three treatments: castrated males, females and immunocastrated males. Each treatment group was replicated three times with five pigs per replicate. The trial period was of 70 days, divided into phases of growing (70 to 110 days old and finishing (111 to 140 days old. The pigs were weighed four times: at the beginning of the trial, at the first immunocastration vaccine dose (80 days old, at the second immunocastration vaccine dose (110 days old and just before slaughter (140 days old. Blood samples were taken on the same day that the animals were weighed. Results. Between 80 and 110 days old, there was an increase in PUN value, only for castrated males and females. No differences were found in weight gain between the studied groups within the periods. Immunocastrated males had lower feed intake than females and these had a lower feed intake than castrated males. To 110 days old, immunocastrated animals showed feed conversion ratio similar to females and better than castrated males. However, after the second dose of the vaccine, feed conversion was similar between groups. Conclusions. The benefits of immunocastration are prominent in animals with low to medium genetic potential.

  12. Potential plasma markers of type 1 and type 2 leprosy reactions: a preliminary report

    Directory of Open Access Journals (Sweden)

    Oliveira Maria

    2009-05-01

    Full Text Available Abstract Background The clinical management of leprosy Type 1 (T1R and Type 2 (T2R reactions pose challenges mainly because they can cause severe nerve injury and disability. No laboratory test or marker is available for the diagnosis or prognosis of leprosy reactions. This study simultaneously screened plasma factors to identify circulating biomarkers associated with leprosy T1R and T2R among patients recruited in Goiania, Central Brazil. Methods A nested case-control study evaluated T1R (n = 10 and TR2 (n = 10 compared to leprosy patients without reactions (n = 29, matched by sex and age-group (+/- 5 years and histopathological classification. Multiplex bead based technique provided profiles of 27 plasma factors including 16 pro inflammatory cytokines: tumor necrosis factor-α (TNF-α, Interferon-γ (IFN-γ, interleukin (IL- IL12p70, IL2, IL17, IL1 β, IL6, IL15, IL5, IL8, macrophage inflammatory protein (MIP-1 alpha (MIP1α, 1 beta (MIP1β, regulated upon activation normal T-cell expressed and secreted (RANTES, monocyte chemoattractrant protein 1 (MCP1, CC-chemokine 11 (CCL11/Eotaxin, CXC-chemokine 10 (CXCL10/IP10; 4 anti inflammatory interleukins: IL4, IL10, IL13, IL1Rα and 7 growth factors: IL7, IL9, granulocyte-colony stimulating factor (G-CSF, granulocyte macrophage-colony stimulating factor (GM-CSF, platelet-derived growth factor BB (PDGF BB, basic fibroblast growth factor (bFGF, vascular endothelial growth factor (VEGF. Results Elevations of plasma CXCL10 (P = 0.004 and IL6 (p = 0.013 were observed in T1R patients compared to controls without reaction. IL6 (p = 0.05, IL7 (p = 0.039, and PDGF-BB (p = 0.041 were elevated in T2R. RANTES and GMCSF were excluded due to values above and below detection limit respectively in all samples. Conclusion Potential biomarkers of T1R identified were CXCL10 and IL6 whereas IL7, PDGF-BB and IL6, may be laboratory markers of TR2. Additional studies on these biomarkers may help understand the

  13. NITROGEN POTENTIAL DURING ION NITRIDING PROCESS IN GLOW-DISCHARGE PLASMA

    Directory of Open Access Journals (Sweden)

    A. A. Kozlov

    2015-01-01

    Full Text Available The paper considers problems on regulation of phase composition of a nitrided layer during gas and ion nitriding process in a glow-discharge. It has been established that  available models for control of nitrided layer structure with the help of nitriding index (nitrogen potential can not be applied for nitriding process in the glow-discharge. Principal difference of the ion nitriding from the gas one is in the fact that chemically active nitrogen is formed in the discharge zone (cathode layer and its mass-transfer is carried out in the form of an active particle flow (ions, atoms, molecules which directed to the metal surface.Interrelation of chemical discharge activity with such characteristics of nitriding steel as nitrogen solubility in  α-solid solution and  coefficient diffusion during ion nitriding in low-discharge plasma. It has been shown that regulation of the nitride layer structure during ion nitriding is reached due to changes in nitrogen flow density in plasma. While supporting the flow at the level of nitrogen solubility in  one phase or another (α, γ′  it is possible to obtain the nitrided layer consisting only of α-solid solution or γ′-nitride layer and diffusion sub-layer. Moreover a specific range of nitrogen flow density values exists for every steel grade where it is possible to ensure a limiting nitrogen concentration in α-solid solution and the γ′-layer characterized by low diffusion  mobility is not formed on the surface.

  14. Effects of exercise intensity on plasma concentrations of appetite-regulating hormones: Potential mechanisms.

    Science.gov (United States)

    Hazell, Tom J; Islam, Hashim; Townsend, Logan K; Schmale, Matt S; Copeland, Jennifer L

    2016-03-01

    The physiological control of appetite regulation involves circulating hormones with orexigenic (appetite-stimulating) and anorexigenic (appetite-inhibiting) properties that induce alterations in energy intake via perceptions of hunger and satiety. As the effectiveness of exercise to induce weight loss is a controversial topic, there is considerable interest in the effect of exercise on the appetite-regulating hormones such as acylated ghrelin, peptide YY (PYY), glucagon-like peptide-1 (GLP-1), and pancreatic polypeptide (PP). Research to date suggests short-term appetite regulation following a single exercise session is likely affected by decreases in acylated ghrelin and increases in PYY, GLP-1, and PP. Further, this exercise-induced response may be intensity-dependent. In an effort to guide future research, it is important to consider how exercise alters the circulating concentrations of these appetite-regulating hormones. Potential mechanisms include blood redistribution, sympathetic nervous system activity, gastrointestinal motility, cytokine release, free fatty acid concentrations, lactate production, and changes in plasma glucose and insulin concentrations. This review of relevant research suggests blood redistribution during exercise may be important for suppressing ghrelin, while other mechanisms involving cytokine release, changes in plasma glucose and insulin concentrations, SNS activity, and muscle metabolism likely mediate changes in the anorexigenic signals PYY and GLP-1. Overall, changes in appetite-regulating hormones following acute exercise appear to be intensity-dependent, with increasing intensity leading to a greater suppression of orexigenic signals and greater stimulation of anorexigenic signals. However, there is less research on how exercise-induced responses in appetite-regulating hormones differ between sexes or different age groups. A better understanding of how exercise intensity and workload affect appetite across the sexes and life

  15. Levels of plasma circulating cell free nuclear and mitochondrial DNA as potential biomarkers for breast tumors

    Directory of Open Access Journals (Sweden)

    Diesch Claude

    2009-11-01

    Full Text Available Abstract Background With the aim to simplify cancer management, cancer research lately dedicated itself more and more to discover and develop non-invasive biomarkers. In this connection, circulating cell-free DNA (ccf DNA seems to be a promising candidate. Altered levels of ccf nuclear DNA (nDNA and mitochondrial DNA (mtDNA have been found in several cancer types and might have a diagnostic value. Methods Using multiplex real-time PCR we investigated the levels of ccf nDNA and mtDNA in plasma samples from patients with malignant and benign breast tumors, and from healthy controls. To evaluate the applicability of plasma ccf nDNA and mtDNA as a biomarker for distinguishing between the three study-groups we performed ROC (Receiver Operating Characteristic curve analysis. We also compared the levels of both species in the cancer group with clinicopathological parameters. Results While the levels of ccf nDNA in the cancer group were significantly higher in comparison with the benign tumor group (P P P P = 0.022. The level of ccf nDNA was also associated with tumor-size (2 cmP = 0.034. Using ROC curve analysis, we were able to distinguish between the breast cancer cases and the healthy controls using ccf nDNA as marker (cut-off: 1866 GE/ml; sensitivity: 81%; specificity: 69%; P P Conclusion Our data suggests that nuclear and mitochondrial ccf DNA have potential as biomarkers in breast tumor management. However, ccf nDNA shows greater promise regarding sensitivity and specificity.

  16. Non linear dynamic of Langmuir and electromagnetic waves in space plasmas; Dinamica nao linear de ondas de Langmuir e eletromagneticas em plasmas espaciais

    Energy Technology Data Exchange (ETDEWEB)

    Guede, Jose Ricardo Abalde

    1995-11-01

    The aim of this work is to study the nonlinear dynamics of Langmuir and electromagnetic waves in space plasmas. Firstly, the generalized Zakharov equations are derived which are used to study the hybrid parametric instability involving the generation of daughter Langmuir, electromagnetic and ion-acoustic waves induced by two counter-propagating Langmuir pump waves with different amplitudes based on a coupled dispersion relation. Secondly, starting from the generalized Zakharov equations the linear and nonlinear coupled mode theories of three-wave and four-wave parametric interactions are developed, respectively. In three-waves processes, a Langmuir wave decays into another Langmuir wave and an ion-acoustic wave (electrostatic parametric decay) or into an electromagnetic wave and an ion-acoustic wave (electromagnetic parametric decay). In four-wave (modulational) processes, the interaction involves two wave triplets: in the decay triplet a pump wave couples with a low-frequency wave to generate a Stokes wave, and in the fusion triplets: in the decay triplet a pump wave couples with a low-frequency wave to generate a Stokes wave, and in the fusion triplet the coupling of a pump wave with a low-frequency wave generate an anti-Stokes wave. These modulational processes are convective and resonant processes wherein the low-frequency modes are Eigenmodes of plasma and are known as the stimulated modulational processes. Four such processes are investigated in this thesis: two with Langmuir pump waves (electrostatic and hybrid stimulated modulation processes) and the other two with electromagnetic pump waves (stimulated modulation Brillouin scattering and electromagnetic stimulated modulation process). Applications of the theoretical results in space plasmas are discussed. In particular, it is shown that the electrostatic and electromagnetic parametric decay processes of Langmuir waves can model the generation and modulation of radio emissions and Langmuir waves in the

  17. The Advantages, Potentials and Safety of VTOL Suborbital Space Tourism Operations

    Science.gov (United States)

    Ridzuan Zakaria, N.; Nasrun, N.; Abu, J.; Jusoh, A.; Azim, L.; Said, A.; Ishak, S.; Rafidi Zakaria, N.

    2012-01-01

    more risky for a suborbital vehicle to fly above such objects after taking off from a spaceport far away from the object, and later returning to the spaceport, the way to go is to have the operation of the suborbital vehicle near the exotic locations. Unfortunately, some exotic locations such as a tropical archipelago in the middle of a clear blue ocean or a permanent icecap on a mountain range with variety of vegetation around it due to differences in height may not have suitable runway to function as spaceport, and for such reason, VTOL (vertical take-off and landing) capability for suborbital tourism vehicle may be worth considered. VTOL suborbital space tourism vehicle may not operate from a remote uneconomical location even though the location is near an exotic viewing target, but such vehicle may operate from a luxury super yacht that can sail to exotic locations around the world, and during the journey, the passengers can be trained and prepared for the flight of their life. Such is an advantage and potential of VTOL suborbital space tourism vehicle, but VTOL operation can be more complex than a conventional operation and therefore will increase the risk of operation, and for this reason the safety issue for such operation is very significant. This paper explores and discusses some advantages and potentials of VTOL suborbital space tourism operations and safety issues related to them. It also describes a couple of proposed concepts of VTOL suborbital tourism vehicles and potential exotic locations on Earth to be viewed from such vehicles.

  18. Plasma-grafted alkaline anion-exchange membranes based on polyvinyl chloride for potential application in direct alcohol fuel cell

    Science.gov (United States)

    Hu, Jue; Zhang, Chengxu; Cong, Jie; Toyoda, Hirotaka; Nagatsu, Masaaki; Meng, Yuedong

    2011-05-01

    Plasma grafting is employed to prepare alkaline anion-exchange membranes in this study. The attenuated total reflection Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and thermo gravimetric analysis demonstrate that the benzyltrimethylammonium cationic groups are successfully introduced into the polyvinyl chloride matrix via plasma grafting, quaternization and alkalization. The plasma-grafted alkaline anion-exchange membrane exhibits a satisfactory ionic exchange capacity (1.01 mmol g-1), thermal stability, mechanical property, ionic conductivity (0.0145 S cm-1) and methanol permeability (9.59 × 10-12 m2 s-1), suggesting a great potential for application in direct alcohol fuel cells. The open circuit voltage of air-breathing ADAFC using plasma-grafted alkaline anion-exchange membrane is 0.796 V with 1 M EtOH solution at ambient temperature.

  19. An integrated time-of-flight versus residual energy subsystem for a compact dual ion composition experiment for space plasmas.

    Science.gov (United States)

    Desai, M I; Ogasawara, K; Ebert, R W; McComas, D J; Allegrini, F; Weidner, S E; Alexander, N; Livi, S A

    2015-05-01

    We have developed a novel concept for a Compact Dual Ion Composition Experiment (CoDICE) that simultaneously provides high quality plasma and energetic ion composition measurements over 6 decades in ion energy in a wide variety of space plasma environments. CoDICE measures the two critical ion populations in space plasmas: (1) mass and ionic charge state composition and 3D velocity and angular distributions of ∼10 eV/q-40 keV/q plasma ions—CoDICE-Lo and (2) mass composition, energy spectra, and angular distributions of ∼30 keV-10 MeV energetic ions—CoDICE-Hi. CoDICE uses a common, integrated Time-of-Flight (TOF) versus residual energy (E) subsystem for measuring the two distinct ion populations. This paper describes the CoDICE design concept, and presents results of the laboratory tests of the TOF portion of the TOF vs. E subsystem, focusing specifically on (1) investigation of spill-over and contamination rates on the start and stop microchannel plate (MCP) anodes vs. secondary electron steering and focusing voltages, scanned around their corresponding model-optimized values, (2) TOF measurements and resolution and angular resolution, and (3) cross-contamination of the start and stop MCPs' singles rates from CoDICE-Lo and -Hi, and (4) energy resolution of avalanche photodiodes near the lower end of the CoDICE-Lo energy range. We also discuss physical effects that could impact the performance of the TOF vs. E subsystem in a flight instrument. Finally, we discuss advantages of the CoDICE design concept by comparing with capabilities and resources of existing flight instruments.

  20. An integrated time-of-flight versus residual energy subsystem for a compact dual ion composition experiment for space plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Desai, M. I.; McComas, D. J.; Allegrini, F.; Livi, S. A. [Space Science and Engineering Division, Southwest Research Institute, 6220 Culebra Road, San Antonio, Texas 78238-5166 (United States); Department of Physics and Astronomy, University of Texas at San Antonio, One UTSA Circle, San Antonio, Texas 78249-0697 (United States); Ogasawara, K.; Ebert, R. W.; Weidner, S. E.; Alexander, N. [Space Science and Engineering Division, Southwest Research Institute, 6220 Culebra Road, San Antonio, Texas 78238-5166 (United States)

    2015-05-15

    We have developed a novel concept for a Compact Dual Ion Composition Experiment (CoDICE) that simultaneously provides high quality plasma and energetic ion composition measurements over 6 decades in ion energy in a wide variety of space plasma environments. CoDICE measures the two critical ion populations in space plasmas: (1) mass and ionic charge state composition and 3D velocity and angular distributions of ∼10 eV/q–40 keV/q plasma ions—CoDICE-Lo and (2) mass composition, energy spectra, and angular distributions of ∼30 keV–10 MeV energetic ions—CoDICE-Hi. CoDICE uses a common, integrated Time-of-Flight (TOF) versus residual energy (E) subsystem for measuring the two distinct ion populations. This paper describes the CoDICE design concept, and presents results of the laboratory tests of the TOF portion of the TOF vs. E subsystem, focusing specifically on (1) investigation of spill-over and contamination rates on the start and stop microchannel plate (MCP) anodes vs. secondary electron steering and focusing voltages, scanned around their corresponding model-optimized values, (2) TOF measurements and resolution and angular resolution, and (3) cross-contamination of the start and stop MCPs’ singles rates from CoDICE-Lo and -Hi, and (4) energy resolution of avalanche photodiodes near the lower end of the CoDICE-Lo energy range. We also discuss physical effects that could impact the performance of the TOF vs. E subsystem in a flight instrument. Finally, we discuss advantages of the CoDICE design concept by comparing with capabilities and resources of existing flight instruments.

  1. Effective potentials for charge-helium and charge-singly-ionized helium interactions in a dense plasma

    Energy Technology Data Exchange (ETDEWEB)

    Ramazanov, T.S.; Amirov, S.M.; Moldabekov, Zh.A. [Institute for Experimental and Theoretical Physics, Al-Farabi Kazakh National University, Almaty (Kazakhstan)

    2016-06-15

    The effective electron (proton)-He and electron (proton)-He{sup +} screened pair interaction potentials arising as a result of partial screening of the helium nucleus field by bound electrons, taking into account both screening by free charged particles and quantum diffraction effect in dense plasmas were derived. The impact of quantum effects on screening was analyzed. It was shown that plasma polarization around the atom leads to the additional repulsion (attraction) between the electron (proton) and the helium atom. The method of constructing the full electron (proton)-He and electron (proton)-He{sup +} screened pair interaction potentials as the sum of the derived potentials with the polarization potential and exchange potential is discussed. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  2. Plasma miR-216a as a potential marker of pancreatic injury in a rat model of acute pancreatitis

    Science.gov (United States)

    Kong, Xiang-Yu; Du, Yi-Qi; Li, Lei; Liu, Jian-Qiang; Wang, Guo-Kun; Zhu, Jia-Qi; Man, Xiao-Hua; Gong, Yan-Fang; Xiao, Li-Ning; Zheng, Yong-Zhi; Deng, Shang-Xin; Gu, Jun-Jun; Li, Zhao-Shen

    2010-01-01

    AIM: To study the potential value and specificity of plasma miR-216a as a marker for pancreatic injury. METHODS: Two rat models were applied in this article: L-arginine-induced acute pancreatitis was used as one model to explore the potential value of plasma miR-216a for detection of pancreatic injury; nonlethal sepsis induced in rats by single puncture cecal ligation and puncture (CLP) was used as the other model to evaluate the specificity of plasma miR-216a compared with two commonly used markers (amylase and lipase) for acute pancreatitis. Plasmas were sampled from rats at indicated time points and total RNA was isolated. Real-Time Quantitative reverse transcriptase-polymerase chain reaction was used to quantify miR-216a in plasmas. RESULTS: In the acute pancreatitis model, among five time points at which plasmas were sampled, miR-216a concentrations were significantly elevated 24 h after arginine administration and remained significantly increased until 48 h after operation (compared with 0 h time point, P < 0.01, Kruskal-Wallis Test). In the CLP model, plasma amylase and lipase, two commonly used biomarkers for acute pancreatitis, were significantly elevated 24 h after operation (compared with 0 h time point, P < 0.01 and 0.05 respectively, Pairwise Bonferroni corrected t-tests), while miR-216a remained undetectable among four tested time points. CONCLUSION: Our article showed for the first time that plasma miR-216a might serve as a candidate marker of pancreatic injury with novel specificity. PMID:20857533

  3. Modulation of waves due to charge-exchange collisions in magnetized partially ionized space plasma

    Energy Technology Data Exchange (ETDEWEB)

    Shaikh, Dastgeer, E-mail: dastgeer.shaikh@uah.ed [Department of Physics and Center for Space Plasma and Aeronomy Research, University of Alabama in Huntsville, Huntsville, AL 35899 (United States); Zank, G.P. [Department of Physics and Center for Space Plasma and Aeronomy Research, University of Alabama in Huntsville, Huntsville, AL 35899 (United States)

    2010-10-04

    A nonlinear time dependent fluid simulation model is developed that describes the evolution of magnetohydrodynamic waves in the presence of collisional and charge exchange interactions of a partially ionized plasma. The partially ionized plasma consists of electrons, ions and a significant number of neutral atoms. In our model, the electrons and ions are described by a single fluid compressible magnetohydrodynamic (MHD) model and are coupled self-consistently to the neutral gas, described by the compressible hydrodynamic equations. Both the plasma and neutral fluids are treated with different energy equations that describe thermal energy exchange processes between them. Based on our self-consistent model, we find that propagating Alfvenic and fast/slow modes grow and damp alternately through a nonlinear modulation process. The modulation appears to be robust and survives strong damping by the neutral component.

  4. Modulation of waves due to charge-exchange collisions in magnetized partially ionized space plasma

    CERN Document Server

    Shaikh, Dastgeer

    2010-01-01

    A nonlinear time dependent fluid simulation model is developed that describes the evolution of magnetohydrodynamic waves in the presence of collisional and charge exchange interactions of a partially ionized plasma. The partially ionized plasma consists of electrons, ions and a significant number of neutral atoms. In our model, the electrons and ions are described by a single fluid compressible magnetohydrodynamic (MHD) model and are coupled self-consistently to the neutral gas, described by the compressible hydrodynamic equations. Both the plasma and neutral fluids are treated with different energy equations that describe thermal energy exchange processes between them. Based on our self-consistent model, we find that propagating Alfv\\'enic and fast/slow modes grow and damp alternately through a nonlinear modulation process. The modulation appears to be robust and survives strong damping by the neutral component.

  5. Assessment of DSN Communication Coverage for Space Missions to Potentially Hazardous Asteroids

    Science.gov (United States)

    Kegege, Obadiah; Bittner, David; Gati, Frank; Bhasin, Kul

    2012-01-01

    A communication coverage gap exists for Deep Space Network (DSN) antennas. This communication coverage gap is on the southern hemisphere, centered at approximate latitude of -47deg and longitude of -45deg. The area of this communication gap varies depending on the altitude from the Earth s surface. There are no current planetary space missions that fall within the DSN communication gap because planetary bodies in the Solar system lie near the ecliptic plane. However, some asteroids orbits are not confined to the ecliptic plane. In recent years, Potentially Hazardous Asteroids (PHAs) have passed within 100,000 km of the Earth. NASA s future space exploration goals include a manned mission to asteroids. It is important to ensure reliable and redundant communication coverage/capabilities for manned space missions to dangerous asteroids that make a sequence of close Earth encounters. In this paper, we will describe simulations performed to determine whether near-Earth objects (NEO) that have been classified as PHAs fall within the DSN communication coverage gap. In the study, we reviewed literature for a number of PHAs, generated binary ephemeris for selected PHAs using JPL s HORIZONS tool, and created their trajectories using Satellite Took Kit (STK). The results show that some of the PHAs fall within DSN communication coverage gap. This paper presents the simulation results and our analyses

  6. Absolute calibration of space-resolving soft X-ray spectrograph for plasma diagnostics

    Science.gov (United States)

    Yoshikawa, M.; Okamoto, Y.; Kawamori, E.; Watanabe, Y.; Watabe, C.; Yamaguchi, N.; Tamano, T.

    2001-07-01

    A grazing incidence flat-field soft X-ray (20-350 Å) spectrograph was constructed and applied for impurity diagnostics in the GAMMA 10 fusion plasma. The spectrograph consisted of a limited height entrance slit, an aberration-corrected concave grating, a microchannel-plate intensified detector and an instant camera/a high speed solid state camera. An absolute calibration experiment for the SX spectrograph was performed at the Photon Factory in the High Energy Accelerator Research Organization with monitoring the incident synchrotron beam intensity by using an absolutely calibrated XUV silicon photodiode. From the results of absolute calibration of the spectrograph, the radiation loss from the plasma was obtained.

  7. Absolute calibration of space-resolving soft X-ray spectrograph for plasma diagnostics

    CERN Document Server

    Yoshikawa, M; Kawamori, E; Watanabe, Y; Watabe, C; Yamaguchi, N; Tamano, T

    2001-01-01

    A grazing incidence flat-field soft X-ray (20-350 A) spectrograph was constructed and applied for impurity diagnostics in the GAMMA 10 fusion plasma. The spectrograph consisted of a limited height entrance slit, an aberration-corrected concave grating, a microchannel-plate intensified detector and an instant camera/a high speed solid state camera. An absolute calibration experiment for the SX spectrograph was performed at the Photon Factory in the High Energy Accelerator Research Organization with monitoring the incident synchrotron beam intensity by using an absolutely calibrated XUV silicon photodiode. From the results of absolute calibration of the spectrograph, the radiation loss from the plasma was obtained.

  8. Plasma transport in the interplanetary space: Percolation and anomalous diffusion of magnetic-field lines

    Energy Technology Data Exchange (ETDEWEB)

    Zimbardo, G.; Veltri, P. [Arcavacata di Rende, Cosenza, Univ. della Calabria (Italy). Dipt. di Fisica

    1997-11-01

    The magnetic fluctuations due to, e.g., magnetohydrodynamic turbulence cause a magnetic-field line random walk that influences many cosmic plasma phenomena. The results of a three-dimensional numerical simulation of a turbulent magnetic field in plane geometry are presented here. Magnetic percolation, Levy flights, and non-Gaussian random walk of the magnetic-field lines are found for moderate perturbation levels. In such a case plasma transport can be anomalous, i.e., either super diffusive or sub diffusive. Increasing the perturbation level a Gaussian diffusion regime is attained. The implications on the structure of the electron fore shock and of planetary magneto pauses are discussed.

  9. Effectiveness of Space Debris Mitigation Guidelines: Economic Potential of LEO and Traffic Management Issues

    Science.gov (United States)

    Belviso, Luciano

    Space debris probably represent one of the major issues for the future development and exploitation of space by all spacefaring nations. Considering the large range of possible mitigation techniques, some general criteria to evaluate them shall be taken into account: cost, effectiveness, technical and legal applicability in order to assess their effectiveness. Even though the Inter Agency Space Debris Coordination Committee (IADC) guidelines are considered as the basis for a new regulatory regime of mitigation, the problem concerning the legal instrument by which the international community would accept these guidelines remains still unsolved. In this paper, we will focus on the following issues: Economic potential of orbital regions. Since the international community lacks consensus to conclude a legally binding instrument, a voluntary adherence regime seems a possible way to apply mitigation measures. However, with mitigation efforts having only small effects into the future, expenditures are not easy to be justified today even if they could reduce the economic consequences of debris in the long period[1]. Some orbital regions, such as the Geostationary Orbit, are already the subject of international agreements, however, the properties of other regions of near-earth space are also distinct as far as their potential economic value is concerned[2]. Therefore, the applicability of mitigation techniques on the basis of cost-benefit analysis will be considered in this paper. Applicability of satellites traffic control. For satellites in Low Earth Orbit, the main hazard is posed by other object located in narrow sets of altitudes and inclinations[4]. Satellites control systems usually allow only a limited number of operation mostly related to small trajectory corrections and they can result not sufficient to avoid collisions with debris. That is why a complementary approach is required although this could represent an additional cost. In this paper we will consider the

  10. Velocity-space sensitivities of neutron emission spectrometers at the tokamaks JET and ASDEX Upgrade in deuterium plasmas

    Science.gov (United States)

    Jacobsen, A. S.; Binda, F.; Cazzaniga, C.; Eriksson, J.; Hjalmarsson, A.; Nocente, M.; Salewski, M.; Tardini, G.

    2017-07-01

    Future fusion reactors are foreseen to be heated by the energetic alpha particles produced in fusion reactions. For this to happen, it is important that the energetic ions are sufficiently confined. In present day fusion experiments, energetic ions are primarily produced using external heating systems such as neutral beam injection and ion cyclotron resonance heating. In order to diagnose these fast ions, several different fast-ion diagnostics have been developed and implemented in the various experiments around the world. The velocity-space sensitivities of fast-ion diagnostics are given by so-called weight functions. Here instrument-specific weight functions are derived for neutron emission spectrometry detectors at the tokamaks JET and ASDEX Upgrade for the 2.45 MeV neutrons produced in deuterium-deuterium reactions in deuterium plasmas. Using these, it is possible to directly determine which part of velocity space each detector observes.

  11. The potential of space observations for pulsating pre-main sequence stars

    CERN Document Server

    Zwintz, Konstanze

    2016-01-01

    The first asteroseismic studies of pre-main sequence (pre-MS) pulsators have been conducted based on data from the space telescopes MOST and CoRoT with typical time bases of less than 40 days. With these data, a relation between the pulsational properties of pre-MS delta Scuti stars and their relative evolutionary phase on their way from the birthline to the zero-age main sequence was revealed. But it is evident from comparison with the more evolved pulsators in their main sequence or post-main sequence stages observed by the main Kepler mission, that many more questions could be addressed with significantly longer time bases and ultra-high precision. Here, I will discuss the observational status of pre-MS asteroseismology and the potential of future space observations for this research field.

  12. MR imaging of hand microcirculation as a potential tool for space glove testing and design

    Science.gov (United States)

    Peterson, Steven W.; Strauss, Alvin M.; Niemann, Trista A.; Lorenz, Christine H.

    1991-01-01

    The task of evaluating and designing space gloves requires accurate biomechanical characterization of the hand. The availability of magnetic resonance (MR) imaging has created new opportunities for in vivo analysis of physiological phenomena such as the relationship between circulation and fatigue. An MR imaging technique originally proposed to quantitatively evaluate cerebral perfusion has been modified to evaluate the capillary microcirculation in hand muscles. An experimental protocol was developed to acquire perfusion-weighted images in the hand before and after various levels of exercise. Preliminary results on the feasibility of applying the MR imaging technique to the study of microcirculation and fatigue in the hand are presented. The potential of this method for space glove testing and design is also discussed.

  13. Nonperturbative renormalization group for scalar fields in de Sitter space: Beyond the local potential approximation

    Science.gov (United States)

    Guilleux, Maxime; Serreau, Julien

    2017-02-01

    Nonperturbative renormalization group techniques have recently proven a powerful tool to tackle the nontrivial infrared dynamics of light scalar fields in de Sitter space. In the present article, we develop the formalism beyond the local potential approximation employed in earlier works. In particular, we consider the derivative expansion, a systematic expansion in powers of field derivatives, appropriate for long wavelength modes, that we generalize to the relevant case of a curved metric with Lorentzian signature. The method is illustrated with a detailed discussion of the so-called local potential approximation prime which, on top of the full effective potential, includes a running (but field-independent) field renormalization. We explicitly compute the associated anomalous dimension for O (N ) theories. We find that it can take large values along the flow, leading to sizable differences as compared to the local potential approximation. However, it does not prevent the phenomenon of gravitationally induced dimensional reduction pointed out in previous studies. We show that, as a consequence, the effective potential at the end of the flow is unchanged as compared to the local potential approximation, the main effect of the running anomalous dimension being merely to slow down the flow. We discuss some consequences of these findings.

  14. Effective momentum-dependent potentials for atomic bound states and scattering in strongly coupled plasmas

    Science.gov (United States)

    Christlieb, A.; Dharuman, G.; Verboncoeur, J.; Murillo, M. S.

    2016-10-01

    Modeling high energy-density experiments requires simulations spanning large length and time scales. These non-equilibrium experiments have time evolving ionization and partial degeneracy, obviating the direct use of the time-dependent Schrodinger equation. Therefore, efficient approximate methods are greatly needed. We have examined the accuracy of one such method based on an effective classical-dynamics approach employing effective momentum dependent potentials (MDPs) within a Hamiltonian framework that enables large-scale simulations. We have found that a commonly used formulation, based on Kirschbaum-Wilets MDPs leads to very accurate ground state energies and good first/second-ionization energies. The continuum scattering properties of free electrons were examined by comparing the momentum-transfer cross section (MTCS) predicted by KW MDP to a semi-classical phase-shift calculation. Optimizing the KW MDP parameters for the scattering process yielded poor MTCSs, suggesting a limitation of the use of KW MDP for plasmas. However, our new MDP yields MTCS values in much better agreement than KW MDP.

  15. Investigation of multifractal nature of floating potential fluctuations obtained from a dc glow discharge magnetized plasma

    Science.gov (United States)

    Shaw, Pankaj Kumar; Saha, Debajyoti; Ghosh, Sabuj; Janaki, M. S.; Iyengar, A. N. Sekar

    2017-03-01

    In this paper, multifractal detrended fluctuation analysis (MF-DFA) has been used to analyze the floating potential fluctuations obtained with a Langmuir probe from a dc glow discharge magnetized plasma device. The generalized Hurst exponents (h(q)) , local fluctuation function (Fq(s)) , the Rényi exponents (τ(q)) and the multifractal spectrum F(α) have been calculated by applying the MF-DFA method. The result of the MF-DFA shows the multifractal nature of these fluctuations. We have investigated the influence of magnetic field on the multifractal nature of the fluctuations and it is seen that degree of multifractality is reduced with the increase in the magnetic field strength. The values of h(q) have been restricted between 0.7 and 1 for the magnetized fluctuations. This result is evidence of the existence of long-range correlations in the fluctuations. Furthermore, we employed shuffle and surrogate approaches to analyze the origins of multifractality. Comparing the MF-DFA results for the data set to those for shuffled and surrogate series, we have found that its multifractal nature is due to the existence of significant long-term correlation.

  16. Asymptotic behavior of correlation functions for electric potential and field fluctuations in a classical one-component plasma

    NARCIS (Netherlands)

    Suttorp, L.G.

    1992-01-01

    The correlations of the electric potential fluctuations in a classical one-component plasma are studied for large distances between the observation points. The two-point correlation function for these fluctuations is known to decay slowly for large distances, even if exponential clustering holds for

  17. The Importance of the Ubiquitous 'Kappa' Distributions in Space Plasmas (Invited)

    Science.gov (United States)

    Scudder, J. D.; Karimabadi, H.

    2013-12-01

    The kappa model for f(v) was originally derived by Olbert (1966) to provide frugal but informative fits to observed particle fluxes from which moments of the underlying plasma could be extracted. Olbert's new fit parameter (kappa) allowed for the ambient plasma to possess reduced kurtosis, which a Gaussian does not. The universality of kappa can easily be overstated, since it cannot fit distributions with a heat flux which is generally important in astrophysical plasmas. Geophysically the frequent use of such a parametrization for the zeroth order energy distribution in the comoving frame acknowledges that the observed plasmas of nature are generally non-thermal, hence kurtotic, which for this author is their principal significance. A key question remains whether the analytically convenient kappa function's kurtotic form is required by the laws of physics, or rather a deft representative of all possible distributions with non-negligible kurtosis and other higher moments. This paper develops why the non-thermal kurtotic f(v) should generally be expected in astrophysical plasmas structured by gravity, driven by their tendency to achieve quasi-neutrality. It will demonstrate the essential role of runaway phenomena in the origin of this kurtosis while showing consistency with observables. This approach provides a rationale why such kurtotic distributions should occur without arguing what its precise shape should be, beyond possessing non-zero skewness and kurtosis. Initial results will be shown that the kappa model for such kurtotic distributions, while better than an Gaussian, may be too rigid to describe the non-thermal distributions of nature at all radial distances from the sun.

  18. Logistics Needs for Potential Deep Space Mission Scenarios Post Asteroid Redirect Crewed Mission

    Science.gov (United States)

    Lopez, Pedro, Jr.; Shultz, Eric; Mattfeld, Bryan; Stromgren, Chel; Goodliff, Kandyce

    2015-01-01

    The Asteroid Redirect Mission (ARM) is currently being explored as the next step towards deep space human exploration, with the ultimate goal of reaching Mars. NASA is currently investigating a number of potential human exploration missions, which will progressively increase the distance and duration that humans spend away from Earth. Missions include extended human exploration in cis-lunar space which, as conceived, would involve durations of around 60 days, and human missions to Mars, which are anticipated to be as long as 1000 days. The amount of logistics required to keep the crew alive and healthy for these missions is significant. It is therefore important that the design and planning for these missions include accurate estimates of logistics requirements. This paper provides a description of a process and calculations used to estimate mass and volume requirements for crew logistics, including consumables, such as food, personal items, gasses, and liquids. Determination of logistics requirements is based on crew size, mission duration, and the degree of closure of the environmental control life support system (ECLSS). Details are provided on the consumption rates for different types of logistics and how those rates were established. Results for potential mission scenarios are presented, including a breakdown of mass and volume drivers. Opportunities for mass and volume reduction are identified, along with potential threats that could possibly increase requirements.

  19. Plasma levels of the tissue inhibitor matrix metalloproteinase-3 as a potential biomarker in oral cancer progression

    Science.gov (United States)

    Su, Chun-Wen; Su, Bo-Feng; Chiang, Whei-Ling; Yang, Shun-Fa; Chen, Mu-Kuan; Lin, Chiao-Wen

    2017-01-01

    Oral cancer is the most common malignancy with poor prognosis and is the fourth most common cancer in men in Taiwan. The tissue inhibitor of metalloproteinase-3 (TIMP3) acts as a tumor suppressor gene by inhibiting the growth, angiogenesis, migration, and invasion of cancer cells. However, few studies have examined the association of plasma TIMP3 levels with oral squamous cell carcinoma (OSCC), and the role of plasma TIMP3 levels in OSCC progression is still unclear. We measured the plasma TIMP3 levels of 450 OSCC patients and 64 healthy controls by using a commercial enzyme-linked immunosorbent assay. We also analyzed TIMP3 mRNA levels of 328 OSCC patients and 32 normal tissues from The Cancer Genome Atlas (TCGA) dataset. Our results revealed that plasma TIMP3 levels were significantly lower in patients with OSCC than in healthy controls (p < 0.001). Moreover, plasma TIMP3 levels in patients with OSCC were significantly associated with the tumor stage and tumor status but not with the lymph node status, metastasis, and cell differentiation. To verify our findings, we also examined TCGA bioinformatics database and discovered similar results for the association with the pathological stage of OSCC. In conclusion, our results suggest that plasma TIMP3 is a potential biomarker for predicting the tumor stage and T status in patients with OSCC. PMID:28138307

  20. Exploring the potential high energy locations and intensities in confined work spaces of waveguide dimensions

    Science.gov (United States)

    Rodriguez, Ricardo; Lewis, Winston G.

    2014-07-01

    review visits the likelihood for potential energy build-up due to RF propagation in confined spaces that are of waveguide design but with larger dimensions. Such confined spaces include silos, tanks, pipes, manholes, air-condition ducts, tunnels, wells, engine rooms and operator rooms on board vessels. In these confined spaces waves reflect off of the walls and combine constructively or destructively with incident waves producing reinforcement or cancellation respectively. Where there is reinforcement, the intensity of the wave for a particular distance in accordance with the standard, may exceed the exposure limit for this distance from the source thereby exposing the worker to larger intensities than the accepted limit and presenting a potential health and safety threat.

  1. Effect of microgravity on plasma catecholamine responses to stressors during space flight.

    Science.gov (United States)

    Kvetnansky, R; Macho, L; Koska, J; Pacak, K; Hoff, T; Ksinantova, L; Noskov, V B; Kobzev, E; Grigoriev, A I; Vigas, M

    2001-07-01

    The effect of microgravity on the sympathicoadrenal system (SAS) activity in humans and animals has not yet been clarified. Our previous studies suggested that the SAS activity, evaluated by circulating and/or urinary catecholamine (CA) levels in astronauts during space flights, was found to be rather unchanged. However, CA levels were measured in astronauts only at rest conditions. The aim of the present study was to investigate effect of microgravity during space flight and post-flight readaptation on responsiveness of the SAS to somatic and psychic stressors evaluated by levels of catecholamines and their metabolite in the blood of the Slovak cosmonaut during his stay on board the space station Mir.

  2. A Method for Measuring Fast Time Evolutions of the Plasma Potential by Means of a Simple Emissive Probe

    DEFF Research Database (Denmark)

    Iizuka, S.; Michelsen, Poul; Juul Rasmussen, Jens;

    1981-01-01

    A method is presented for obtaining the temporal evolution of the plasma potential, which is assumed to be given by the floating potential of a simple emissive probe. The construction of the probe is also described. The method avoids the slow time response of the usual technique where the floating...... potential is measured across a high resistance. During each sweep of the probe voltage, the changing of the sign of the probe current, which is sampled at a specific time, gives rise to a negative pulse, driving the pen-lift of an X-Y recorder. Since the real floating potential is measured where the probe...

  3. Plasma Amino Acids Profiles in Children with Autism: Potential Risk of Nutritional Deficiencies.

    Science.gov (United States)

    Arnold, Georgianne L.; Hyman, Susan L.; Mooney, Robert A.; Kirby, Russell S.

    2003-01-01

    The plasma amino acid profiles of 10 children with autism on gluten and casein restricted diets and 26 on unrestricted diets were reviewed. There was a trend for the children on restricted diets to have an increased prevalence of essential amino acid deficiencies and lower plasma levels of essential acids. (Contains references.) (Author/CR)

  4. Plasma Amino Acids Profiles in Children with Autism: Potential Risk of Nutritional Deficiencies.

    Science.gov (United States)

    Arnold, Georgianne L.; Hyman, Susan L.; Mooney, Robert A.; Kirby, Russell S.

    2003-01-01

    The plasma amino acid profiles of 10 children with autism on gluten and casein restricted diets and 26 on unrestricted diets were reviewed. There was a trend for the children on restricted diets to have an increased prevalence of essential amino acid deficiencies and lower plasma levels of essential acids. (Contains references.) (Author/CR)

  5. Whimsicality of multi-mode Hasegawa space-charge waves in a complex plasma containing collision-dominated electrons and streaming ions

    Science.gov (United States)

    Lee, Myoung-Jae; Jung, Young-Dae

    2017-09-01

    The influence of collision-dominated electrons on multi-mode Hasegawa space-charge waves are investigated in a complex plasma containing streaming ions. The dispersion relation for the multi-mode Hasegawa space-charge wave propagating in a cylindrical waveguide filled with dusty plasma containing collision-dominated electrons and streaming ions is derived by using the fluid equations and Poisson’s equation which lead to a Bessel equation. By the boundary condition, the roots of the Bessel function would characterize the property of space-charge wave propagation. It is found that two solutions exist for wave frequency, which are affected by the radius of waveguide and the roots of the Bessel function. The damping and growing modes are found to be enhanced by an increase of the radius. However, an increase of electron collision frequency would suppress the damping and the growing modes of the propagating space-charge wave in a cylindrical waveguide plasma.

  6. Cold Atmospheric Plasma Generated in Water and its Potential Use in Cancer Therapy

    CERN Document Server

    Chen, Zhitong; Lin, Li; Keidar, Michael

    2016-01-01

    Cold atmospheric plasma (CAP) has been emerged as a novel technology for cancer treatment. CAP can directly treat cells and tissue but such direct application is limited to skin or can be invoked as a supplement during open surgery. In this letter we report indirect plasma treatment using CAP produced in a water using three gases as carrier (argon, helium and nitrogen). Plasma stimulated water was applied to human breast cancer cell line (MDA-MB-231). MTT assays tests showed that using argon plasma had the strongest effect on inducing apoptosis in cultured human breast cancer cells. This result is attributed to the elevated production of the reactive oxygen species and reactive nitrogen species in water in the case of argon plasma.

  7. Searching for transition paths in multidimensional space with a fixed repulsive bias potential

    Science.gov (United States)

    Trushin, O. S.; Salo, P.; Ala-Nissila, T.; Ying, S. C.

    2004-01-01

    An efficient method for searching for transition paths in a multidimensional configuration space is proposed. It is based on using a fixed, locally repulsive bias potential, which forces the system to move from a given initial state to a different final state. This simple method is very effective in determining nearby configurations and possible transition paths for many-particle systems. Once the approximate transition paths are known, the corresponding activation energies can be computed using, e.g., the nudged elastic band method. The usefulness of the present method is demonstrated for both classical and quantum-mechanical systems.

  8. Tourism-dominated spaces – the strategic potential of hotel lobbies

    DEFF Research Database (Denmark)

    Pasgaard, Jens Christian

    2013-01-01

    and not least by economists. The architectural voice in the general tourism-related discussion, in a very wide sense, has been relatively vague. The aim of this article is to discuss the strategic potential of a specific tourism programme, namely the hotel lobby as well as the immediate urban context...... of this lobby. From a qualitative architectural point of view the article examines the evolution of specific lobby-qualities at Miami Beach; from the pre-war Art Deco hotel lobby to the post-war MiMo resort lobby. In particular, the study highlights ‘extraordinary’ qualities of tourism-dominated spaces (as...

  9. Tourism-dominated spaces – the strategic potential of hotel lobbies

    DEFF Research Database (Denmark)

    Pasgaard, Jens Christian

    2013-01-01

    and not least by economists. The architectural voice in the general tourism-related discussion, in a very wide sense, has been relatively vague. The aim of this article is to discuss the strategic potential of a specific tourism programme, namely the hotel lobby as well as the immediate urban context...... of this lobby. From a qualitative architectural point of view the article examines the evolution of specific lobby-qualities at Miami Beach; from the pre-war Art Deco hotel lobby to the post-war MiMo resort lobby. In particular, the study highlights ‘extraordinary’ qualities of tourism-dominated spaces (as...

  10. A Light-Cone QCD Inspired Meson Model with a Relativistic Confining Potential in Momentum Space

    Institute of Scientific and Technical Information of China (English)

    LI Lei; WANG Shun-Jin; ZHOU Shan-Gui; ZHANG Guang-Biao

    2007-01-01

    For describing the radial excited states a relativistic confining potential in momentum space is included in the meson effective light-cone Hamiltonian. The meson eigen equations are transformed from the front form to the instant form and formulated in total angular representation. Details about numerically solving these equations are discussed, mainly focusing on treating singularities arising from one-gluon exchange interactions and confinement. The results of pseudo-scalar mesons indicate that the improved meson effective light-cone Hamiltonian can describe the ground states and radial excited states well. Some radial excited states are also predicted and waiting for experimental test.

  11. THE NON-CUTOFF BOLTZMANN EQUATION WITH POTENTIAL FORCE IN THE WHOLE SPACE

    Institute of Scientific and Technical Information of China (English)

    Yuanjie LEI

    2014-01-01

    This paper is concerned with the non-cutoff Boltzmann equation for full-range interactions with potential force in the whole space. We establish the global existence and optimal temporal convergence rates of classical solutions to the Cauchy problem when initial data is a small perturbation of the stationary solution. The analysis is based on the time-weighted energy method building also upon the recent studies of the non-cutoff Boltzmann equation in [1-3, 15] and the non-cutoff Vlasov-Poisson-Boltzmann system [6].

  12. A study of potential energy curves from the model space quantum Monte Carlo method

    Energy Technology Data Exchange (ETDEWEB)

    Ohtsuka, Yuhki; Ten-no, Seiichiro, E-mail: tenno@cs.kobe-u.ac.jp [Department of Computational Sciences, Graduate School of System Informatics, Kobe University, Nada-ku, Kobe 657-8501 (Japan)

    2015-12-07

    We report on the first application of the model space quantum Monte Carlo (MSQMC) to potential energy curves (PECs) for the excited states of C{sub 2}, N{sub 2}, and O{sub 2} to validate the applicability of the method. A parallel MSQMC code is implemented with the initiator approximation to enable efficient sampling. The PECs of MSQMC for various excited and ionized states are compared with those from the Rydberg-Klein-Rees and full configuration interaction methods. The results indicate the usefulness of MSQMC for precise PECs in a wide range obviating problems concerning quasi-degeneracy.

  13. Time- and space-resolved spectroscopic characterization of laser-induced swine muscle tissue plasma

    Energy Technology Data Exchange (ETDEWEB)

    Camacho, J.J. [Departamento de Química-Física Aplicada, Facultad de Ciencias, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid (Spain); Diaz, L., E-mail: luis.diaz@csic.es [Instituto de Estructura de la Materia, CFMAC, CSIC, Serrano 121, 28006 Madrid (Spain); Martinez-Ramirez, S. [Instituto de Estructura de la Materia, CFMAC, CSIC, Serrano 121, 28006 Madrid (Spain); Caceres, J.O. [Departamento de Química Analítica, Facultad de Ciencias Químicas, Universidad Complutense, Cuidad Universitaria, 28040 Madrid (Spain)

    2015-09-01

    The spatial-temporal evolution of muscle tissue sample plasma induced by a high-power transversely excited atmospheric (TEA) CO{sub 2} pulsed laser at vacuum conditions (0.1–0.01 Pa) has been investigated using high-resolution optical emission spectroscopy (OES) and imaging methods. The induced plasma shows mainly electronically excited neutral Na, K, C, Mg, H, Ca, N and O atoms, ionized C{sup +}, C{sup 2+}, C{sup 3+}, Mg{sup +}, Mg{sup 2+}, N{sup +}, N{sup 2+}, Ca{sup +}, O{sup +} and O{sup 2+} species and molecular band systems of CN(B{sup 2}Σ{sup +}–X{sup 2}Σ{sup +}), C{sub 2}(d{sup 3}Π{sub g}–a{sup 3}Π{sub u}), CH(B{sup 2}Σ{sup −}–X{sup 2}Π; A{sup 2}Δ–X{sup 2}Π), NH(A{sup 3}Π–X{sup 3}Σ{sup −}), OH(A{sup 2}Σ{sup +}–X{sup 2} Σ{sup +}), and CaOH(B{sup 2}Σ{sup +}–X{sup 2}Σ{sup +}; A{sup 2}Π–X{sup 2}Σ{sup +}). Time-resolved two-dimensional emission spectroscopy is used to study the expanded distribution of different species ejected during ablation. Spatial and temporal variations of different atoms and ionic excited species are reported. Plasma parameters such as electron density and temperature were measured from the spatio-temporal analysis of different species. Average velocities of some plasma species were estimated. - Highlights: • LIBS of swine muscle tissue sample generated by CO{sub 2} laser pulses has been done for the first time. • Average velocities of some plasma species have been calculated from spatial and temporally resolved 2D OES images. • Electron density (~ 9 × 10{sup 17} cm{sup -3}) has been studied with spatial and temporal resolution. • Temporal evolution of the plasma temperature has been calculated by means of Boltzmann plots.

  14. The limit passage of space curvature in problems of celestial mechanics with the generalized Kepler and Hooke potentials

    Science.gov (United States)

    Vozmishcheva, Tatiana

    2016-09-01

    The connection between the problems of celestial mechanics: the Kepler problem, the two-center problem and the two body problem in spaces of constant curvature with the generalized Kepler and Hooke potentials is investigated. The limit passage in the two-center and two body problems in the Lobachevsky space and on a sphere is carried out as λto0 (λ is the curvature of the corresponding space) for the two potentials. The potentials and metrics in spaces under study are written in the gnomonic coordinates. It is shown that as the curvature radius tends to infinity, the generalized gravitational and elastic potentials transform to the Kepler and Hooke forms in the Euclidean space.

  15. Plasma cadmium and zinc and their interrelationship in adult Nigerians: potential health implications

    Directory of Open Access Journals (Sweden)

    Ugwuja Emmanuel Ike

    2015-06-01

    Full Text Available Zinc (an essential trace element and cadmium (a ubiquitous environmental pollutant with acclaimed toxicity have been found to occur together in nature, with reported antagonism between the two elements. The present study aimed at determination of plasma levels of zinc (Zn and cadmium (Cd and their interrelationship in adult Nigerians. The series comprised adults (n=443 aged ≥18 yrs (mean ± SD 38.4±13.7 yrs, consisting of 117 males, 184 non-pregnant and 140 pregnant females. Sociodemographic data were collected by questionnaire while anthropometrics were determined using standard methods. Plasma Cd and Zn were determined by using an atomic absorption spectrophotometer. The mean plasma zinc and cadmium were 94.7±18.1 μg/dl and 0.150±0.548 μg/dl, respectively. Age, sex, pregnancy, and parity had no effect on either plasma Zn or Cd. Although educational level had no effect on plasma Zn, it had a significant effect on Cd; subjects possessing either secondary or tertiary education had significantly lower plasma Cd than subjects without formal education. Moreover, there seemed to be an inverse relationship between Cd and Zn, but this was not statistically significant (r=–0.089; p=0.061. Although plasma Zn was not related to BMI (r=0.037; p=0.432, Cd was significantly negatively correlated with BMI (r=–0.124; p=0.009. It may be concluded that adult Nigerians in Ebonyi State have elevated plasma levels of Cd, with apparent impact on the levels of plasma Zn. This has important public health implications considering the essential roles of Zn in the protection of Cd mediated adverse health effects. While food diversification is recommended to improve plasma Zn, efforts should be made to reduce exposure to Cd to mitigate partially its possible adverse effects.

  16. Case Studies in Space Charge and Plasma Acceleration of Charged Beams

    CERN Document Server

    Bazzani, A; Londrillo, P; Sinigardi, S; Turchetti, G

    2014-01-01

    Plasma acceleration with electron or proton driver beams is a challenging opportunity for high energy physics. An energy doubling experiment with electron drivers was successfully performed at SLAC and a key experiment AWAKE with proton drivers is on schedule at CERN. Simulations play an important role in choosing the best experimental conditions and in interpreting the results. The Vlasov equation is the theoretical tool to describe the interaction of a driver particle beam or a driver laser pulse with a plasma. Collective effects, such as tune shift and mismatch instabilities, appear in high intensity standard accelerators and are described by the Poisson-Vlasov equation. In the paper we review the Vlasov equation in electrostatic and fully electromagnetic case. The general framework of variational principles is used to derive the equation, the local form of the balance equations and related conservation laws. In the electrostatic case we remind the analytic Kapchinskij-Vladimirskij (K-V) model and we propo...

  17. THIN CURRENT SHEETS AND ASSOCIATED ELECTRON HEATING IN TURBULENT SPACE PLASMA

    Energy Technology Data Exchange (ETDEWEB)

    Chasapis, A.; Retinò, A.; Sahraoui, F.; Canu, P. [Laboratoire de Physique des Plasmas, Ecole Polytechnique, Palaiseau, F-91128 (France); Vaivads, A.; Khotyaintsev, Yu. V. [Swedish Institute of Space Physics, Uppsala (Sweden); Sundkvist, D. [Space Sciences Laboratory, University of California, Berkeley, CA (United States); Greco, A. [Dipartimento di Fisica, Universita della Calabria (Italy); Sorriso-Valvo, L., E-mail: alexandros.chasapis@lpp.polytechnique.fr [IMIP-CNR, U.O.S. LICRYL di Cosenza (Italy)

    2015-05-01

    Intermittent structures, such as thin current sheets, are abundant in turbulent plasmas. Numerical simulations indicate that such current sheets are important sites of energy dissipation and particle heating occurring at kinetic scales. However, direct evidence of dissipation and associated heating within current sheets is scarce. Here, we show a new statistical study of local electron heating within proton-scale current sheets by using high-resolution spacecraft data. Current sheets are detected using the Partial Variance of Increments (PVI) method which identifies regions of strong intermittency. We find that strong electron heating occurs in high PVI (>3) current sheets while no significant heating occurs in low PVI cases (<3), indicating that the former are dominant for energy dissipation. Current sheets corresponding to very high PVI (>5) show the strongest heating and most of the time are consistent with ongoing magnetic reconnection. This suggests that reconnection is important for electron heating and dissipation at kinetic scales in turbulent plasmas.

  18. Thin Current Sheets and Associated Electron Heating in Turbulent Space Plasma

    Science.gov (United States)

    Chasapis, A.; Retinò, A.; Sahraoui, F.; Vaivads, A.; Khotyaintsev, Yu. V.; Sundkvist, D.; Greco, A.; Sorriso-Valvo, L.; Canu, P.

    2015-05-01

    Intermittent structures, such as thin current sheets, are abundant in turbulent plasmas. Numerical simulations indicate that such current sheets are important sites of energy dissipation and particle heating occurring at kinetic scales. However, direct evidence of dissipation and associated heating within current sheets is scarce. Here, we show a new statistical study of local electron heating within proton-scale current sheets by using high-resolution spacecraft data. Current sheets are detected using the Partial Variance of Increments (PVI) method which identifies regions of strong intermittency. We find that strong electron heating occurs in high PVI (>3) current sheets while no significant heating occurs in low PVI cases (5) show the strongest heating and most of the time are consistent with ongoing magnetic reconnection. This suggests that reconnection is important for electron heating and dissipation at kinetic scales in turbulent plasmas.

  19. On the role of ion-scale whistler waves in space and astrophysical plasma turbulence

    Science.gov (United States)

    Comişel, Horia; Nariyuki, Yasuhiro; Narita, Yasuhito; Motschmann, Uwe

    2016-11-01

    Competition of linear mode waves is studied numerically to understand the energy cascade mechanism in plasma turbulence on ion-kinetic scales. Hybrid plasma simulations are performed in a text">3-D simulation box by pumping large-scale Alfvén waves on the fluid scale. The result is compared with that from our earlier text">2-D simulations. We find that the whistler mode is persistently present both in the text">2-D and text">3-D simulations irrespective of the initial setup, e.g., the amplitude of the initial pumping waves, while all the other modes are excited and damped such that the energy is efficiently transported to thermal energy over non-whistler mode. The simulation results suggest that the whistler mode could transfer the fluctuation energy smoothly from the fluid scale down to the electron-kinetic scale, and justifies the notion of whistler turbulence.

  20. On the ordinary mode Weibel instability in space plasmas: A comparison of three-particle distributions

    Science.gov (United States)

    Rubab, Nazish; Chian, Abraham C.-L.; Jatenco-Pereira, Vera

    2016-03-01

    Electromagnetic wave fluctuations driven by temperature anisotropy in plasmas are of interest for solar flare, solar corona, and solar wind studies. We investigate the dispersion characteristics of electromagnetic wave propagating perpendicular to the uniform magnetic field which is derived by using multiple particle distribution functions: Maxwellian, bi-kappa, and product bi-kappa. The presence of temperature anisotropy in which the parallel plasma kinetic energy density exceeding by a sufficient amount can lead to Weibel-like electromagnetic instability. A general description is made to calculate the growth/damping rates of Weibel-like modes when the temperature anisotropy and nonthermal features are associated with these distributions. We demonstrate that for the zeroth cyclotron harmonic, our results for bi-Maxwellian and bi-kappa overlap with each other, while the product bi-kappa distribution shows some dependence on parallel kappa index. For higher harmonics, the growth rates vanish and the damping prevails.