Sample records for density plasma science

  1. 2810 IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 39, NO. 11, NOVEMBER 2011 The Effect of Critical Plasma Densities of

    E-Print Network [OSTI]

    Harilal, S. S.

    -produced plasma (LPP) for various applications should consider details of spatial and temporal input power de in hydro- dynamic evolution of the produced plasma sources. Index Terms--CO2 laser, critical density and optimization of radiation sources for the next generation of nanolithography, i.e., the extreme ultravi- olet

  2. 844 IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 34, NO. 3, JUNE 2006 Energy Balance and Plasma Potential in Low-Density

    E-Print Network [OSTI]

    Kaganovich, Igor

    844 IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 34, NO. 3, JUNE 2006 Energy Balance and Plasma, and Zoltan Sternovsky Abstract--Electron energy balance is shown to play an impor- tant role in determining that satisfy the energy balance equation. The ion loss rate af- fects the electron loss rate through the quasi

  3. The temperature dependence of equilibrium plasma density

    E-Print Network [OSTI]

    B. V. Vasiliev

    2002-03-17T23:59:59.000Z

    Temperature dependence of an electron-nuclear plasma equilibrium density is considered basing on known approaches, which are given in (1)(2). It is shown that at a very high temperature, which is characteristic for a star interior, the equilibrium plasma density is almost constant and equals approximately to $10^{25}$ particles per $cm^3$. At a relatively low temperature, which is characteristic for star surface, the equilibrium plasma density is in several orders lower and depends on temperature as $T^{3/2}$.

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

    SciTech Connect (OSTI)

    A. Dunaevsky; N.J. Fisch

    2003-10-02T23:59:59.000Z

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

  5. Using Radio Waves to Control Fusion Plasma Density

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Using Radio Waves to Control Fusion Plasma Density Using Radio Waves to Control Fusion Plasma Density Simulations Run at NERSC Support Fusion Experiments at MIT, General Atomics...

  6. High Energy Density Laboratory Plasmas Program | National Nuclear...

    National Nuclear Security Administration (NNSA)

    Photo Gallery Jobs Apply for Our Jobs Our Jobs Working at NNSA Blog Home High Energy Density Laboratory Plasmas Program High Energy Density Laboratory Plasmas Program...

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

    E-Print Network [OSTI]

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

  8. Extreme hydrogen plasma densities achieved in a linear plasma generator

    SciTech Connect (OSTI)

    Rooij, G. J. van; Veremiyenko, V. P.; Goedheer, W. J.; de Groot, B.; Kleyn, A. W.; Smeets, P. H. M.; Versloot, T. W.; Whyte, D. G.; Engeln, R.; Schram, D. C.; Cardozo, N. J. Lopes [FOM-Institute for Plasma Physics Rijnhuizen, Association EURATOM-FOM, Trilateral Euregio Cluster, Nieuwegein, Uthrecht 3430BE (Netherlands); Massachusetts Institute of Technology, Cambridge, Massachusetts 02139-4307 (United States); FOM-Institute for Plasma Physics Rijnhuizen, Association EURATOM-FOM, Trilateral Euregio Cluster, Nieuwegein, Uthrecht 3430BE (NL) and Eindhoven University of Technology, 5600 MB Eindhoven (Netherlands)

    2007-03-19T23:59:59.000Z

    A magnetized hydrogen plasma beam was generated with a cascaded arc, expanding in a vacuum vessel at an axial magnetic field of up to 1.6 T. Its characteristics were measured at a distance of 4 cm from the nozzle: up to a 2 cm beam diameter, 7.5x10{sup 20} m{sup -3} electron density, {approx}2 eV electron and ion temperatures, and 3.5 km/s axial plasma velocity. This gives a 2.6x10{sup 24} H{sup +} m{sup -2} s{sup -1} peak ion flux density, which is unprecedented in linear plasma generators. The high efficiency of the source is obtained by the combined action of the magnetic field and an optimized nozzle geometry. This is interpreted as a cross-field return current that leads to power dissipation in the beam just outside the source.

  9. N.P. Basse1 Plasma Science and Fusion Center

    E-Print Network [OSTI]

    Basse, Nils Plesner

    ) The energy spectrum E(k) is related to P(k) through E(k) = Ad × P(k), where Ad is the surface area 33rd IEEE International Conference on Plasma Science, Traverse City, Michigan, USA (2006) A study of multiscale density fluctuations Work supported by US DoE Office of Fusion Energy Sciences #12;Introduction

  10. Exploration of Plasma Jets Approach to High Energy Density Physics

    SciTech Connect (OSTI)

    Chen, Chiping [Massachusetts Institute of Technology

    2013-08-26T23:59:59.000Z

    High-energy-density laboratory plasma (HEDLP) physics is an emerging, important area of research in plasma physics, nuclear physics, astrophysics, and particle acceleration. While the HEDLP regime occurs at extreme conditions which are often found naturally in space but not on the earth, it may be accessible by colliding high intensity plasmas such as high-energy-density plasma jets, plasmoids or compact toroids from plasma guns. The physics of plasma jets is investigated in the context of high energy density laboratory plasma research. This report summarizes results of theoretical and computational investigation of a plasma jet undergoing adiabatic compression and adiabatic expansion. A root-mean-squared (rms) envelope theory of plasma jets is developed. Comparison between theory and experiment is made. Good agreement between theory and experiment is found.

  11. ISRAELI PLASMA SCIENCE AND TECHNOLOGY ASSOCIATION

    E-Print Network [OSTI]

    AND APPLICATIONS H.I.T. ­ Holon Institute of Technology February 4th, 2013 BOOK OF ABSTRACTS http://plasma-gate.weizmann.ac.il/ipsta2013/ #12;15th Israeli Conference on Plasma Science and Applications, HIT, Holon, February 4th , 2013 2 Science and Applications, HIT, Holon, February 4th , 2013 3 PREFACE We are delighted to host the 15th

  12. Ducted kinetic Alfven waves in plasma with steep density gradients

    SciTech Connect (OSTI)

    Houshmandyar, Saeid [Solar Observatory Department, Prairie View A and M University, Prairie View, Texas 77446 (United States); Department of Physics, West Virginia University, Morgantown, West Virginia 26506-6315 (United States); Scime, Earl E. [Department of Physics, West Virginia University, Morgantown, West Virginia 26506-6315 (United States)

    2011-11-15T23:59:59.000Z

    Given their high plasma density (n {approx} 10{sup 13} cm{sup -3}), it is theoretically possible to excite Alfven waves in a conventional, moderate length (L {approx} 2 m) helicon plasma source. However, helicon plasmas are decidedly inhomogeneous, having a steep radial density gradient, and typically have a significant background neutral pressure. The inhomogeneity introduces regions of kinetic and inertial Alfven wave propagation. Ion-neutral and electron-neutral collisions alter the Alfven wave dispersion characteristics. Here, we present the measurements of propagating kinetic Alfven waves in helium helicon plasma. The measured wave dispersion is well fit with a kinetic model that includes the effects of ion-neutral damping and that assumes the high density plasma core defines the radial extent of the wave propagation region. The measured wave amplitude versus plasma radius is consistent with the pile up of wave magnetic energy at the boundary between the kinetic and inertial regime regions.

  13. Local thermodynamic equilibrium in rapidly heated high energy density plasmas

    SciTech Connect (OSTI)

    Aslanyan, V.; Tallents, G. J. [York Plasma Institute, Department of Physics, University of York, Heslington, York YO10 5DD (United Kingdom)

    2014-06-15T23:59:59.000Z

    Emission spectra and the dynamics of high energy density plasmas created by optical and Free Electron Lasers (FELs) depend on the populations of atomic levels. Calculations of plasma emission and ionization may be simplified by assuming Local Thermodynamic Equilibrium (LTE), where populations are given by the Saha-Boltzmann equation. LTE can be achieved at high densities when collisional processes are much more significant than radiative processes, but may not be valid if plasma conditions change rapidly. A collisional-radiative model has been used to calculate the times taken by carbon and iron plasmas to reach LTE at varying densities and heating rates. The effect of different energy deposition methods, as well as Ionization Potential Depression are explored. This work shows regimes in rapidly changing plasmas, such as those created by optical lasers and FELs, where the use of LTE is justified, because timescales for plasma changes are significantly longer than the times needed to achieve an LTE ionization balance.

  14. Atomic processes in high-density plasmas

    SciTech Connect (OSTI)

    More, R.M.

    1982-12-21T23:59:59.000Z

    This review covers dense atomic plasmas such as that produced in inertial confinement fusion. The target implosion physics along with the associated atomic physics, i.e., free electron collision phenomena, electron states I, electron states II, and nonequilibrium plasma states are described. (MOW)

  15. Effect of bias application to plasma density in weakly magnetized inductively coupled plasma

    SciTech Connect (OSTI)

    Kim, Hyuk; Lee, Woohyun; Park, Wanjae; Whang, Ki-Woong [Plasma Laboratory, Department of Electrical Engineering and Computer Science, Seoul National University, 599 Kwanak-ro, Kwanak-gu, Seoul 151-742 (Korea, Republic of)

    2013-07-15T23:59:59.000Z

    Independent control of the ion flux and energy can be achieved in a dual frequency inductively coupled plasma (ICP) system. Typically, the plasma density is controlled by the high-frequency antenna radio-frequency (RF) power and the ion energy is controlled by the low-frequency bias RF power. Increasing the bias power has been known to cause a decrease in the plasma density in capacitively coupled discharge systems as well as in ICP systems. However, an applied axial magnetic field was found to sustain or increase the plasma density as bias power is increased. Measurements show higher electron temperatures but lower plasma densities are obtained in ordinary ICP systems than in magnetized ICP systems under the same neutral gas pressure and RF power levels. Explanations for the difference in the behavior of plasma density with increasing bias power are given in terms of the difference in the heating mechanism in ordinary unmagnetized and magnetized ICP systems.

  16. Measurements of neutral helium density in helicon plasmas

    SciTech Connect (OSTI)

    Houshmandyar, Saeid; Sears, Stephanie H.; Thakur, Saikat Chakraborty; Carr, Jerry Jr.; Galante, Matthew E.; Scime, Earl E. [Department of Physics, West Virginia University, Morgantown, West Virginia 26506-6315 (United States)

    2010-10-15T23:59:59.000Z

    Laser-induced-fluorescence (LIF) is used to measure the density of helium atoms in a helicon plasma source. For a pump wavelength of 587.725 nm (vacuum) and laser injection along the magnetic field, the LIF signal exhibits a signal decrease at the Doppler shifted central wavelength. The drop in signal results from the finite optical depth of the plasma and the magnitude of the decrease is proportional to the density of excited state neutral atoms. Using Langmuir probe measurements of plasma density and electron temperature and a collisional-radiative model, the absolute ground state neutral density is calculated from the optical depth measurements. Optimal plasma performance, i.e., the largest neutral depletion on the axis of the system, is observed for antenna frequencies of 13.0 and 13.5 MHz and magnetic field strengths of 550-600 G.

  17. Robotics Science & Technology for Burning Plasma Experiments

    E-Print Network [OSTI]

    Robotics Science & Technology for Burning Plasma Experiments J. N. Herndon, T. W. Burgess, M. M, General Atomics, San Diego, California. #12;Robotics Challenges in Burning Plasma Experiments · Control x x x x x x earthmoving equipment electric robots Conventional Machines DMHP Machines x x x x

  18. Relation between plasma plume density and gas flow velocity in atmospheric pressure plasma

    SciTech Connect (OSTI)

    Yambe, Kiyoyuki; Taka, Shogo; Ogura, Kazuo [Graduate School of Science and Technology, Niigata University, Niigata 950-2181 (Japan)] [Graduate School of Science and Technology, Niigata University, Niigata 950-2181 (Japan)

    2014-04-15T23:59:59.000Z

    We have studied atmospheric pressure plasma generated using a quartz tube, helium gas, and copper foil electrode by applying RF high voltage. The atmospheric pressure plasma in the form of a bullet is released as a plume into the atmosphere. To study the properties of the plasma plume, the plasma plume current is estimated from the difference in currents on the circuit, and the drift velocity is measured using a photodetector. The relation of the plasma plume density n{sub plu}, which is estimated from the current and the drift velocity, and the gas flow velocity v{sub gas} is examined. It is found that the dependence of the density on the gas flow velocity has relations of n{sub plu} ? log(v{sub gas}). However, the plasma plume density in the laminar flow is higher than that in the turbulent flow. Consequently, in the laminar flow, the density increases with increasing the gas flow velocity.

  19. A microwave interferometer for small and tenuous plasma density measurements

    SciTech Connect (OSTI)

    Tudisco, O.; Falcetta, C.; De Angelis, R.; Florean, M.; Neri, C.; Mazzotta, C.; Pollastrone, F.; Rocchi, G.; Tuccillo, A. A. [ENEA CR Frascati, Via E. Fermi 45, 00044 Frascati (Italy); Lucca Fabris, A.; Manente, M.; Ferri, F.; Tasinato, L.; Trezzolani, F. [CISAS 'G.Colombo,' Universita degli studi di Padova, Via Venezia 15, 35131 Padova (Italy); Accatino, L. [ACC Antenna and MW tech, Via Trieste 16/B, 10098 Rivoli (Italy); Pavarin, D. [Dip. di Ingegneria Industriale (DII), Universita degli Studi di Padova, Via Venezia 1, 35131 Padova (Italy); Selmo, A. [RESIA, Studio Progettazione e Realizzazione di Apparati Elettronici, via Roma 17, 37041 Albaredo d'Adige (Italy)

    2013-03-15T23:59:59.000Z

    The non-intrusive density measurement of the thin plasma produced by a mini-helicon space thruster (HPH.com project) is a challenge, due to the broad density range (between 10{sup 16} m{sup -3} and 10{sup 19} m{sup -3}) and the small size of the plasma source (2 cm of diameter). A microwave interferometer has been developed for this purpose. Due to the small size of plasma, the probing beam wavelength must be small ({lambda}= 4 mm), thus a very high sensitivity interferometer is required in order to observe the lower density values. A low noise digital phase detector with a phase noise of 0.02 Degree-Sign has been used, corresponding to a density of 0.5 Multiplication-Sign 10{sup 16} m{sup -3}.

  20. Tunable Laser Plasma Accelerator based on Longitudinal Density Tailoring

    SciTech Connect (OSTI)

    Gonsalves, Anthony; Nakamura, Kei; Lin, Chen; Panasenko, Dmitriy; Shiraishi, Satomi; Sokollik, Thomas; Benedetti, Carlo; Schroeder, Carl; Geddes, Cameron; Tilborg, Jeroen van; Osterhoff, Jens; Esarey, Eric; Toth, Csaba; Leemans, Wim

    2011-07-15T23:59:59.000Z

    Laser plasma accelerators have produced high-quality electron beams with GeV energies from cm-scale devices and are being investigated as hyperspectral fs light sources producing THz to {gamma}-ray radiation and as drivers for future high-energy colliders. These applications require a high degree of stability, beam quality and tunability. Here we report on a technique to inject electrons into the accelerating field of a laser-driven plasma wave and coupling of this injector to a lower-density, separately tunable plasma for further acceleration. The technique relies on a single laser pulse powering a plasma structure with a tailored longitudinal density profile, to produce beams that can be tuned in the range of 100-400 MeV with percent-level stability, using laser pulses of less than 40 TW. The resulting device is a simple stand-alone accelerator or the front end for a multistage higher-energy accelerator.

  1. Fabrication of spatial transient-density structures as high-field plasma photonic devices

    E-Print Network [OSTI]

    /plasma density structures with such a scheme is an essential step in the development of plasma photonic devices by a subse- quent long heater pulse, the plasma density is greatly re- duced as a result of hydrodynamic

  2. Stable laser–plasma accelerators at low densities

    SciTech Connect (OSTI)

    Li, Song; Hafz, Nasr A. M., E-mail: nasr@sjtu.edu.cn; Mirzaie, Mohammad; Ge, Xulei; Sokollik, Thomas; Chen, Min; Sheng, Zhengming; Zhang, Jie, E-mail: jzhang1@sjtu.edu.cn [Key Laboratory for Laser Plasmas (Ministry of Education) and Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China)

    2014-07-28T23:59:59.000Z

    We report stable laser wakefield acceleration using 17–50 TW laser pulses interacting with 4?mm-long helium gas jet. The initial laser spot size was relatively large (28??m) and the plasma densities were 0.48–2.0?×?10{sup 19?}cm{sup ?3}. High-quality 100–MeV electron beams were generated at the plasma density of 7.5?×?10{sup 18?}cm{sup ?3}, at which the beam parameters (pointing angle, energy spectrum, charge, and divergence angle) were measured and stabilized. At higher densities, filamentation instability of the laser-plasma interaction was observed and it has led to multiple wakefield accelerated electron beams. The experimental results are supported by 2D particle-in-cell simulations. The achievement presented here is an important step toward the use of laser-driven accelerators in real applications.

  3. Observation of low magnetic field density peaks in helicon plasma

    SciTech Connect (OSTI)

    Barada, Kshitish K.; Chattopadhyay, P. K.; Ghosh, J.; Kumar, Sunil; Saxena, Y. C. [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India)

    2013-04-15T23:59:59.000Z

    Single density peak has been commonly observed in low magnetic field (<100 G) helicon discharges. In this paper, we report the observations of multiple density peaks in low magnetic field (<100 G) helicon discharges produced in the linear helicon plasma device [Barada et al., Rev. Sci. Instrum. 83, 063501 (2012)]. Experiments are carried out using argon gas with m = +1 right helical antenna operating at 13.56 MHz by varying the magnetic field from 0 G to 100 G. The plasma density varies with varying the magnetic field at constant input power and gas pressure and reaches to its peak value at a magnetic field value of {approx}25 G. Another peak of smaller magnitude in density has been observed near 50 G. Measurement of amplitude and phase of the axial component of the wave using magnetic probes for two magnetic field values corresponding to the observed density peaks indicated the existence of radial modes. Measured parallel wave number together with the estimated perpendicular wave number suggests oblique mode propagation of helicon waves along the resonance cone boundary for these magnetic field values. Further, the observations of larger floating potential fluctuations measured with Langmuir probes at those magnetic field values indicate that near resonance cone boundary; these electrostatic fluctuations take energy from helicon wave and dump power to the plasma causing density peaks.

  4. Plasma Chemistry and Plasma Processing, Vol. 22, No. 2, June 2002 ( 2002) Electron Density and Energy Distributions in

    E-Print Network [OSTI]

    Chen, Junhong

    Plasma Chemistry and Plasma Processing, Vol. 22, No. 2, June 2002 ( 2002) Electron Density in the corona plasma is required to quantify the chemical processes. In this paper, the electron density- ness of the plasma and the electron energy distribution are not affected. Smaller electrodes produce

  5. Plasma ionization frequency, edge-to-axis density ratio, and density on axis of a cylindrical gas discharge

    SciTech Connect (OSTI)

    Palacio Mizrahi, J. H. [Physics Department, Technion, Haifa 32000 (Israel)

    2014-06-15T23:59:59.000Z

    A rigorous derivation of expressions, starting from the governing equations, for the ionization frequency, edge-to-axis ratio of plasma density, plasma density at the axis, and radially averaged plasma density in a cylindrical gas discharge has been obtained. The derived expressions are simple and involve the relevant parameters of the discharge: Cylinder radius, axial current, and neutral gas pressure. The found expressions account for ion inertia, ion temperature, and changes in plasma ion collisionality.

  6. Dusty plasma diagnostics methods for charge, electron temperature, and ion density

    E-Print Network [OSTI]

    Goree, John

    of these efforts have been focused on the sheath region of the plasma, but here we will focus on the main plasmaDusty plasma diagnostics methods for charge, electron temperature, and ion density Bin Liu,1 J Q and two plasma parameters, electron temperature Te, and ion density ni, in the main plasma region

  7. Helicon Plasma Source Configuration Analysis by Means of Density Measurements

    SciTech Connect (OSTI)

    Angrilli, F.; Barber, G.C.; Carter, M.D.; Goulding, R.H.; Maggiora, R.; Pavarin, D.; Sparks, D.O.

    1999-11-13T23:59:59.000Z

    Initial results have been obtained from operation of a helicon plasma source built to conduct optimization studies for space propulsion applications. The source features an easily reconfigurable antenna to test different geometries. Operating with He as the source gas, peak densities >= 1.6X10{sup 19} m{sup -3} have been achieved. Radial and axial plasma profiles have been obtained using a microwave interferometer that can be scanned axially and a Langmuir probe. The source will be used to investigate operation at high magnetic field, frequency, and input power.

  8. Magnetohydrodynamically stable plasma with supercritical current density at the axis

    SciTech Connect (OSTI)

    Burdakov, A. V. [Budker Institute of Nuclear Physics, 11 Lavrentjev Avenue, 630090 Novosibirsk (Russian Federation); Novosibirsk State Technical University, 20 Karl Marks Avenue, 630092 Novosibirsk (Russian Federation); Postupaev, V. V., E-mail: V.V.Postupaev@inp.nsk.su; Sudnikov, A. V. [Budker Institute of Nuclear Physics, 11 Lavrentjev Avenue, 630090 Novosibirsk (Russian Federation); Novosibirsk State University, 2 Pirogova st., 630090 Novosibirsk (Russian Federation)

    2014-05-15T23:59:59.000Z

    In this work, an analysis of magnetic perturbations in the GOL-3 experiment is given. In GOL-3, plasma is collectively heated in a multiple-mirror trap by a high-power electron beam. During the beam injection, the beam-plasma interaction maintains a high-level microturbulence. This provides an unusual radial profile of the net current (that consists of the beam current, current of the preliminary discharge, and the return current). The plasma core carries supercritical current density with the safety factor well below unity, but as a whole, the plasma is stable with q(a)???4. The net plasma current is counter-directed to the beam current; helicities of the magnetic field in the core and at the edge are of different signs. This forms a system with a strong magnetic shear that stabilizes the plasma core in good confinement regimes. We have found that the most pronounced magnetic perturbation is the well-known n?=?1, m?=?1 mode for both stable and disruptive regimes.

  9. IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 32, NO. 2, APRIL 2004 813 Characterization of Laser Produced Tetrakis

    E-Print Network [OSTI]

    Scharer, John E.

    an electrodeless UV laser preionization of TMAE to initiate a plasma seeded in atmospheric pressure gases that can the initiation RF power budget. A large volume (500 cc), high-density ( 1013 cm 3), electrodeless plasmaIEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 32, NO. 2, APRIL 2004 813 Characterization of Laser

  10. Plasma density gradient injection of low absolute momentum spread electron bunches

    E-Print Network [OSTI]

    Geddes, C.G.R.

    2008-01-01T23:59:59.000Z

    t to the plasma density indicates the laser focus positionplasma exit. Scanning the jet position relative to the laser focus (

  11. The expansion of a collisionless plasma into a plasma of lower density

    SciTech Connect (OSTI)

    Perego, M.; Gunzburger, M. D. [Department of Scientific Computing, Florida State University, Tallahassee, Florida 32306 (United States)] [Department of Scientific Computing, Florida State University, Tallahassee, Florida 32306 (United States); Howell, P. D.; Ockendon, J. R.; Allen, J. E. [OCIAM, Mathematical Institute, Oxford University, 24-29 St Giles, OX1 3LB Oxford (United Kingdom)] [OCIAM, Mathematical Institute, Oxford University, 24-29 St Giles, OX1 3LB Oxford (United Kingdom)

    2013-05-15T23:59:59.000Z

    This paper considers the asymptotic and numerical solution of a simple model for the expansion of a collisionless plasma into a plasma of lower density. The dependence on the density ratio of qualitative and quantitative features of solutions of the well-known cold-ion model is explored. In the cold-ion limit, we find that a singularity develops in the ion density in finite time unless the density ratio is zero or close to unity. The classical cold-ion model may cease to be valid when such a singularity occurs and we then regularize the model by the finite ion-temperature Vlasov-Poisson system. Numerical evidence suggests the emergence of a multi-modal velocity distribution.

  12. Radio Scintillation due to Discontinuities in the Interstellar Plasma Density

    E-Print Network [OSTI]

    Hendrik Lambert; Barney Rickett

    1999-11-18T23:59:59.000Z

    We develop the theory of interstellar scintillation as caused by an irregular plasma having a power-law spatial density spectrum with a spectral exponent of 4 corresponding to a medium with abrupt changes in its density. An ``outer scale'' is included in the model representing the typical scale over which the density of the medium remains uniform. Such a spectrum could be used to model plasma shock fronts in supernova remnants or other plasma discontinuities. We investigate and develop equations for the decorrelation bandwidth of diffractive scintillations and the refractive scintillation index and compare our results with pulsar measurements. We consider both a medium concentrated in a thin layer and an extended irregular medium. We conclude that the discontinuity model gives satisfactory agreement for many diffractive measurements, in particular the VLBI meaurements of the structure function exponent between 5/3 and 2. However, it gives less satisfactory agreement for the refractive scintillation index than does the Kolmogorov turbulence spectrum. The comparison suggests that the medium consists of a pervasive background distribution of turbulence embedded with randomly placed discrete plasma structures such as shocks or HII regions. This can be modeled by a composite spectrum following the Kolmogorov form at high wavenumbers and steepening at lower wavenumbers corresponding to the typical (inverse) size of the discrete structures. Such a model can also explain the extreme scattering events. However, lines of sight through the enhanced scattering prevalent at low galactic latitudes are accurately described by the Kolmogorov spectrum in an extended medium and do not appear to have a similar low-wavenumber steepening.

  13. PLASMA FOCUSING OF HIGH ENERGY DENSITY ELECTRON AND POSITRON BEAMS \\Lambda

    E-Print Network [OSTI]

    PLASMA FOCUSING OF HIGH ENERGY DENSITY ELECTRON AND POSITRON BEAMS \\Lambda J.S.T. Ng, P. Chen, W present results from the SLAC E­150 experiment on plasma focusing of high energy density electron and of the SLAC E­150 experiment are to study plasma focusing for high energy, high density par­ ticle beams

  14. Plasma Chemistries for High Density Plasma Etching of SiC

    SciTech Connect (OSTI)

    Cho, H.; Hahn, Y.B.; Hays, D.A.; Hong, J.; Jung, K.B.; Lester, L.F.; Ostling, M.; Pearton, S.J.; Shul, R.J.; Zetterling, C.-M; Zhang, L.

    1998-11-10T23:59:59.000Z

    A variety of different plasma chemistries, including SF6, Cl2, IC1 and IBr, have been examined for dry etching of 6H-SiC in high ion density plasma tools (Inductively Coupled Plasma and Electron Cyclotron Resonance). Rates up to 4,500~"min-1 were obtained for SF6 plasmas, while much lower rates (S800~.min-') were achieved with Cl2, ICl and IBr. The F2- based chemistries have poor selectivity for SiC over photoresist masks (typically 0.4-0.5), but Ni masks are more robust, and allow etch depths 210pm in the SiC. A micromachining process (sequential etch/deposition (<2,000Angstrom min-1) for SiC steps) designed for Si produces relatively low etch rates.

  15. Dependence of various SOL widths on plasma current and density in NSTX H-mode plasmas

    SciTech Connect (OSTI)

    Ahn, J; Maingi, R; Boedo, J; Soukhanovskii, V A

    2009-02-12T23:59:59.000Z

    The dependence of various SOL widths on the line-averaged density ({ovr n}{sub e}) and plasma current (l{sub p}) for the quiescent H-mode plasmas with Type-V ELMs in the National Spherical Torus Experiment (NSTX) was investigated. It is found that the heat flux SOL width ({lambda}{sub q}), measured by the IR camera, is virtually insensitive to {ovr n}{sub e} and has a strong negative dependence on l{sub p}. This insensitivity of {lambda}{sub q} to {ovr n}{sub e} is consistent with the scaling law from JET H-mode plasmas that shows a very weak dependence on the upstream density. The electron temperature, ion saturation current density, electron density, and electron pressure decay lengths ({lambda}{sub Te}, {lambda}{sub jsat}, {lambda}{sub ne}, and {lambda}{sub pe}, respectively) measured by the probe showed that {lambda}{sub Te} and {lambda}{sub jsat} have strong negative dependence on l{sub p}, whereas {lambda}{sub ne} and {lambda}{sub pe} revealed only a little or no dependence. The dependence of {lambda}{sub Te} on l{sub p} is consistent with the scaling law in the literature while {lambda}{sub ne} and {lambda}{sub pe} dependence shows a different trend.

  16. Potential Materials Science Benefits from a Burning Plasma

    E-Print Network [OSTI]

    Potential Materials Science Benefits from a Burning Plasma Science Experiment S.J. Zinkle Oak Ridge;Introduction · The main materials science advances from a BPSX would occur during the R&D phase prior to construction ­e.g., CIT/BPX, ITER · Materials science opportunities during operation of a BPSX would likely

  17. MIT Plasma Science and Fusion Center Fusion Technology & Engineering Division

    E-Print Network [OSTI]

    Fusion Technology & Engineering Division 1. Costing of 4 "Reference" Options 2. Equalization of TF;MIT Plasma Science and Fusion Center Fusion Technology & Engineering Division Total Cost (M$) vs. A; MMIT Plasma Science and Fusion Center Fusion Technology & Engineering Division J.H. Schultz M

  18. Modeling of free electronic state density in hydrogenic plasmas based on nearest neighbor approximation

    SciTech Connect (OSTI)

    Nishikawa, Takeshi, E-mail: nishikawa.takeshi@okayama-u.ac.jp [Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530 (Japan)

    2014-07-15T23:59:59.000Z

    Most conventional atomic models in a plasma do not treat the effect of the plasma on the free-electron state density. Using a nearest neighbor approximation, the state densities in hydrogenic plasmas for both bound and free electrons were evaluated and the effect of the plasma on the atomic model (especially for the state density of the free electron) was studied. The model evaluates the electron-state densities using the potential distribution formed by the superposition of the Coulomb potentials of two ions. The potential from one ion perturbs the electronic state density on the other. Using this new model, one can evaluate the free-state density without making any ad-hoc assumptions. The resulting contours of the average ionization degree, given as a function of the plasma temperature and density, are shifted slightly to lower temperatures because of the effect of the increasing free-state density.

  19. Effect of density changes on tokamak plasma confinement

    E-Print Network [OSTI]

    Spineanu, F

    2015-01-01T23:59:59.000Z

    A change of the particle density (by gas puff, pellets or impurity seeding) during the plasma discharge in tokamak produces a radial current and implicitly a torque and rotation that can modify the state of confinement. After ionization the newly born ions will evolve toward the periodic neoclassical orbits (trapped or circulating) but the first part of their excursion, which precedes the periodicity, is an effective radial current. It is short, spatially finite and unique for each new ion, but multiplied by the rate of ionization and it can produce a substantial total radial current. The associated torque induces rotation which modify the transport processes. We derive the magnitude of the radial current induced by ionization by three methods: the analysis of a simple physical picture, a numerical model and the neoclassical drift-kinetic treatment. The results of the three approaches are in agreement and show that the current can indeed be substantial. Many well known experimental observations can be reconsi...

  20. Relaxation of potential, flows, and density in the edge plasma of CASTOR tokamak

    E-Print Network [OSTI]

    Boyer, Edmond

    Relaxation of potential, flows, and density in the edge plasma of CASTOR tokamak M. Hron1 , V on the CASTOR tokamak. A biased electrode has been used to polarize the edge plasma. The edge plasma potential time in the range of 10 - 30 µs when the electrode biasing is turn off in the CASTOR tokamak

  1. Approach for control of high-density plasma reactors through optimal pulse shaping*

    E-Print Network [OSTI]

    Raja, Laxminarayan L.

    Approach for control of high-density plasma reactors through optimal pulse shaping* Tyrone L and it relies on a physical model of the plasma reactor used in conjunction with an optimal control algorithm surface in a HDP reactor can be biased separately to enable relatively independent control over plasma

  2. Assessment of plasma impedance probe for measuring electron density and collision frequency in a plasma with spatial and temporal gradients

    SciTech Connect (OSTI)

    Hopkins, Mark A., E-mail: mahopkin@mtu.edu; King, Lyon B. [Mechanical Engineering-Engineering Mechanics, Michigan Technological University, 815 R. L. Smith BLDG, Houghton, Michigan 49930 (United States)] [Mechanical Engineering-Engineering Mechanics, Michigan Technological University, 815 R. L. Smith BLDG, Houghton, Michigan 49930 (United States)

    2014-05-15T23:59:59.000Z

    Numerical simulations and experimental measurements were combined to determine the ability of a plasma impedance probe (PIP) to measure plasma density and electron collision frequency in a plasma containing spatial gradients as well as time-varying oscillations in the plasma density. A PIP is sensitive to collision frequency through the width of the parallel resonance in the Re[Z]-vs.-frequency characteristic, while also being sensitive to electron density through the zero-crossing of the Im[Z]-vs.-frequency characteristic at parallel resonance. Simulations of the probe characteristic in a linear plasma gradient indicated that the broadening of Re[Z] due to the spatial gradient obscured the broadening due to electron collision frequency, preventing a quantitative measurement of the absolute collision frequency for gradients considered in this study. Simulation results also showed that the PIP is sensitive to relative changes in electron collision frequency in a spatial density gradient, but a second broadening effect due to time-varying oscillations made collision frequency measurements impossible. The time-varying oscillations had the effect of causing multiple zero-crossings in Im[Z] at parallel resonance. Results of experiments and simulations indicated that the lowest-frequency zero-crossing represented the lowest plasma density in the oscillations and the highest-frequency zero-crossing represented the highest plasma density in the oscillations, thus the PIP probe was found to be an effective tool to measure both the average plasma density as well as the maximum and minimum densities due to temporal oscillations.

  3. Influence of microwave driver coupling design on plasma density at Testbench for Ion sources Plasma Studies, a 2.45 GHz Electron Cyclotron Resonance Plasma Reactor

    SciTech Connect (OSTI)

    Megía-Macías, A.; Vizcaíno-de-Julián, A. [E.S.S. Bilbao, Edificio Cosimet, Landabarri 2, 48940-Leioa, Vizcaya (Spain)] [E.S.S. Bilbao, Edificio Cosimet, Landabarri 2, 48940-Leioa, Vizcaya (Spain); Cortázar, O. D., E-mail: dcortazar@essbilbao.org [E.S.S. Bilbao, Edificio Cosimet, Landabarri 2, 48940-Leioa, Vizcaya (Spain); Universidad de Castilla-La Mancha, ETSII, C.J. Cela s/n, 13170 Ciudad Real (Spain)

    2014-03-15T23:59:59.000Z

    A comparative study of two microwave driver systems (preliminary and optimized) for a 2.45 GHz hydrogen Electron Cyclotron Resonance plasma generator has been conducted. The influence on plasma behavior and parameters of stationary electric field distribution in vacuum, i.e., just before breakdown, along all the microwave excitation system is analyzed. 3D simulations of resonant stationary electric field distributions, 2D simulations of external magnetic field mapping, experimental measurements of incoming and reflected power, and electron temperature and density along the plasma chamber axis have been carried out. By using these tools, an optimized set of plasma chamber and microwave coupler has been designed paying special attention to the optimization of stationary electric field value in the center of the plasma chamber. This system shows a strong stability on plasma behavior allowing a wider range of operational parameters and even sustaining low density plasma formation without external magnetic field. In addition, the optimized system shows the capability to produce values of plasma density four times higher than the preliminary as a consequence of a deeper penetration of the magnetic resonance surface in relative high electric field zone by keeping plasma stability. The increment of the amount of resonance surface embedded in the plasma under high electric field is suggested as a key factor.

  4. Density modification by two superposing TE{sub 10} modes in a plasma filled rectangular waveguide

    SciTech Connect (OSTI)

    Tomar, Sanjay K.; Malik, Hitendra K. [Plasma Waves and Particle Acceleration Laboratory, Department of Physics, Indian Institute of Technology Delhi, New Delhi 110 016 (India)] [Plasma Waves and Particle Acceleration Laboratory, Department of Physics, Indian Institute of Technology Delhi, New Delhi 110 016 (India)

    2013-07-15T23:59:59.000Z

    Microwave and plasma interaction is examined via two fundamental TE{sub 10} modes propagating in a plasma filled rectangular waveguide after superposing at a smaller angle. The propagation of the resultant mode realized from these two modes is governed by a wave equation obtained using the Maxwell's equations. This equation is solved numerically using fourth order Runge-Kutta method for the field amplitude of the microwave in the waveguide considering the waveguide to be made up of a perfect conductor and filled with different types of initial plasma density distributions, viz. homogeneous density, linear density with gradient in the propagation direction, and the density with Gaussian profile along the waveguide width. A phenomenon similar to the duct formation by high power microwaves is found to take place, where the plasma density attains interesting profiles. These profiles can be controlled by the angle of superposition, phase difference between the fields of the two modes, microwave frequency and microwave field amplitude.

  5. Plasma Facing Component Science and Technology for Burning Plasma Experiments

    E-Print Network [OSTI]

    HeatFlux(MW/m2 ) Disruptions Reentry Vehicles Fusion Divertor Fusion First Wall Fast Breeder Fission Reactor Radiant Flux at Sun Surface Rocket Nozzles Comparison Relative Heat Fluxes Fusion Plasma #12;MAU prediction of disruptions about 50 ms before they occur with a >90% accuracy ­ Massive gas puffing

  6. A Simple Relation between Plasma Density and Temperature in the Scrape-Off Layer of High Recycling Divertors

    E-Print Network [OSTI]

    A Simple Relation between Plasma Density and Temperature in the Scrape-Off Layer of High Recycling Divertors

  7. Magnetohydrodynamics in Tokamak Reactors and its Effect on Plasma Density

    E-Print Network [OSTI]

    Morelli, Franco

    2011-12-01T23:59:59.000Z

    on our ability to maintain current standards. Looking ahead, plasma fusion is a means of yielding vast amounts of clean, renewable and virtually limitless amounts of energy. With many advancements taking place since the 1950’s, the current Tokamak reactor...

  8. Plasma density from Cerenkov radiation, betatron oscillations, and beam steering in a plasma wakefield experiment at 30 GeV

    SciTech Connect (OSTI)

    Catravas, P.; Chattopadhyay, S.; Esarey, E.; Leemans, W.P.; Assmann, R.; Decker, F.-J.; Hogan, M.J.; Iverson, R.; Siemann, R.H.; Walz, D.; Whittum, D.; Blue, B.; Clayton, C.; Joshi, C.; Marsh, K.; Mori, W.B.; Wang, S.; Katsouleas, T.; Lee, S.; Muggli, P.

    2001-01-01T23:59:59.000Z

    A method for using Cerenkov radiation near atomic spectral lines to measure plasma source properties for plasma wakefield applications has been discussed and experimentally verified. Because the radiation co-propagates with the electron beam, the radiation samples the source properties exactly along the path of interest with perfect temporal synchronization. Observation wavelengths were chosen with respect to the atomic resonances of the plasma source, where the relative change in the index of refraction strongly affects the Cerenkov cone angle, and permits flexible diagnostic design. The Cerenkov spatial profiles were systematically studied for a Lithium heat pipe oven as a function of oven temperature and observation wavelength. Neutral densities and plasma densities were extracted from the measurements.

  9. Characterization of low-frequency density fluctuations in dipole-confined laboratory plasmas

    E-Print Network [OSTI]

    Ellsworth, Jennifer L

    2010-01-01T23:59:59.000Z

    Low-frequency fluctuations of plasma density, floating potential, ion saturation current, visible light intensity, and edge magnetic field are routinely observed in the Levitated Dipole Experiment (LDX). For the purposes ...

  10. Density profiles of plasmas confined by the field of a Levitating Dipole Magnet

    E-Print Network [OSTI]

    Boxer, Alexander C

    2009-01-01T23:59:59.000Z

    A 4-channel microwave interferometer (center frequency: 60 GHz) has been constructed to measure the density profiles of plasmas confined within the Levitated Dipole Experiment (LDX). LDX is the first and only experiment ...

  11. Stationary self-focusing of intense laser beam in cold quantum plasma using ramp density profile

    SciTech Connect (OSTI)

    Habibi, M. [Department of Physics, Shirvan Branch, Islamic Azad University, Shirvan (Iran, Islamic Republic of); Ghamari, F. [Department of Physics, Khorramabad Branch, Islamic Azad University, Khorramabad (Iran, Islamic Republic of)

    2012-10-15T23:59:59.000Z

    By using a transient density profile, we have demonstrated stationary self-focusing of an electromagnetic Gaussian beam in cold quantum plasma. The paper is devoted to the prospects of using upward increasing ramp density profile of an inhomogeneous nonlinear medium with quantum effects in self-focusing mechanism of high intense laser beam. We have found that the upward ramp density profile in addition to quantum effects causes much higher oscillation and better focusing of laser beam in cold quantum plasma in comparison to that in the classical relativistic case. Our computational results reveal the importance and influence of formation of electron density profiles in enhancing laser self-focusing.

  12. Tuning the electron energy by controlling the density perturbation position in laser plasma accelerators

    SciTech Connect (OSTI)

    Brijesh, P.; Thaury, C.; Phuoc, K. T.; Corde, S.; Lambert, G.; Malka, V. [Laboratoire d'Optique Appliquee, ENSTA ParisTech, CNRS UMR7639, Ecole Polytechnique, 91761 Palaiseau (France); Mangles, S. P. D.; Bloom, M.; Kneip, S. [Blackett Laboratory, Imperial College, London SW7 2AZ (United Kingdom)

    2012-06-15T23:59:59.000Z

    A density perturbation in an underdense plasma was used to improve the quality of electron bunches produced in the laser-plasma wakefield acceleration scheme. Quasi-monoenergetic electrons were generated by controlled injection in the longitudinal density gradients of the density perturbation. By tuning the position of the density perturbation along the laser propagation axis, a fine control of the electron energy from a mean value of 60 MeV to 120 MeV has been demonstrated with a relative energy-spread of 15 {+-} 3.6%, divergence of 4 {+-} 0.8 mrad, and charge of 6 {+-} 1.8 pC.

  13. COALITION FOR PLASMA SCIENCE Fusion Power Associates

    E-Print Network [OSTI]

    · Materials: brochure, two-pagers, posters. · Web page (plasmacoalition.org): links to plasma sites, evaluated of the CPS web site ­ Ask for input on how to improve web page · Solicit for individual(s) to conduct

  14. Plasma density inside a femtosecond laser filament in air: Strong dependence on external focusing

    E-Print Network [OSTI]

    Becker, Andreas

    Plasma density inside a femtosecond laser filament in air: Strong dependence on external focusing­16 . The plasma generation balances the self-focusing effect and leads to a limited peak intensity 17­19 along, Germany Received 10 March 2006; published 27 September 2006 Our experiment shows that external focusing

  15. Advances and Challenges in Computational Plasma Science

    SciTech Connect (OSTI)

    W.M. Tang; V.S. Chan

    2005-01-03T23:59:59.000Z

    Scientific simulation, which provides a natural bridge between theory and experiment, is an essential tool for understanding complex plasma behavior. Recent advances in simulations of magnetically-confined plasmas are reviewed in this paper with illustrative examples chosen from associated research areas such as microturbulence, magnetohydrodynamics, and other topics. Progress has been stimulated in particular by the exponential growth of computer speed along with significant improvements in computer technology.

  16. Electron density and temperature profile diagnostics for C-2 field reversed configuration plasmas

    SciTech Connect (OSTI)

    Deng, B. H.; Kinley, J. S.; Schroeder, J. [Tri Alpha Energy, Inc., Rancho Santa Margarita, California 92688 (United States)

    2012-10-15T23:59:59.000Z

    The 9-point Thomson scattering diagnostic system for the C-2 field reversed configuration plasmas is improved and the measured electron temperature profiles are consistent with theoretical expectations. Rayleigh scattering revealed a finite line width of the ruby laser emission, which complicates density calibration. Taking advantage of the plasma wobble motion, density profile reconstruction accuracy from the 6-chord two-color CO{sub 2}/HeNe interferometer data is improved.

  17. Modeling aluminum etch chemistry in high density plasmas

    SciTech Connect (OSTI)

    Meeks, E. [Sandia National Labs., Livermore, CA (United States); Ho, P.; Buss, R. [Sandia National Labs., Albuquerque, NM (United States)

    1997-08-01T23:59:59.000Z

    The authors have assembled a chemical reaction mechanism that describes the BCl{sub 3}/Cl{sub 2}/Ar plasma etch of Al metallization layers. The reaction set for gas-phase and surface processes was derived either from literature data or estimated from data on related systems. A well-mixed reactor model was used to develop the mechanism and test it against experimental measurements of plasma species and etch-rates in processing reactors. Finally, use of reduced chemistry mechanisms are demonstrated in 2-D simulations for a complex reactor geometry.

  18. Energy enhancement of proton acceleration in combinational radiation pressure and bubble by optimizing plasma density

    SciTech Connect (OSTI)

    Bake, Muhammad Ali; Xie Baisong [Key Laboratory of Beam Technology and Materials Modification of the Ministry of Education, Beijing Normal University, Beijing 100875 (China); College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Shan Zhang [Department of Mathematics and Physics, Shijiazhuang Tiedao University, Shijiazhuang 050043 (China); Hong Xueren [College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); College of Physics and Electronic Engineering, Northwest Normal University, Lanzhou 730070 (China); Wang Hongyu [Department of Physics, Anshan Normal University, Anshan 114005 (China); Shanghai Bright-Tech Information Technology Co. Ltd, Shanghai 200136 (China)

    2012-08-15T23:59:59.000Z

    The combinational laser radiation pressure and plasma bubble fields to accelerate protons are researched through theoretical analysis and numerical simulations. The dephasing length of the accelerated protons bunch in the front of the bubble and the density gradient effect of background plasma on the accelerating phase are analyzed in detail theoretically. The radiation damping effect on the accelerated protons energy is also considered. And it is demonstrated by two-dimensional particle-in-cell simulations that the protons bunch energy can be increased by using the background plasma with negative density gradient. However, radiation damping makes the maximal energy of the accelerated protons a little reduction.

  19. Independent control of electron energy and density using a rotating magnetic field in inductively coupled plasmas

    SciTech Connect (OSTI)

    Kondo, Takahiro; Ohta, Masayuki; Ito, Tsuyohito; Okada, Shigefumi [Center for Atomic and Molecular Technologies, Graduate School of Engineering, Osaka University, Osaka 565-0871 (Japan)] [Center for Atomic and Molecular Technologies, Graduate School of Engineering, Osaka University, Osaka 565-0871 (Japan)

    2013-09-21T23:59:59.000Z

    Effects of a rotating magnetic field (RMF) on the electron energy distribution function (EEDF) and on the electron density are investigated with the aim of controlling the radical composition of inductively coupled plasmas. By adjusting the RMF frequency and generation power, the desired electron density and electron energy shift are obtained. Consequently, the amount and fraction of high-energy electrons, which are mostly responsible for direct dissociation processes of raw molecules, will be controlled externally. This controllability, with no electrode exposed to plasma, will enable us to control radical components and their flux during plasma processing.

  20. Lower hybrid current drive at plasma densities required for thermonuclear reactors

    SciTech Connect (OSTI)

    Cesario, R.; Cardinali, A.; Castaldo, C.; Tuccillo, A. A.; Amicucci, L. [Associazione EURATOM/ENEA sulla Fusione, Centro Ricerche Frascati, 00044 Frascati (Italy)

    2011-12-23T23:59:59.000Z

    Driving current in high-density plasmas is essential for the progress of thermonuclear fusion energy research based on the tokamak concept. The lower hybrid current drive (LHCD) effect, is potentially the most suitable tool for driving current at large plasma radii, consistent with the needs of ITER steady state scenario. Unfortunately, experiments at reactor grade high plasma densities with kinetic profiles approaching those required for ITER, have shown problems in penetration of the LH power into the core plasma. These plasmas represent a basic reference for designing possible methods useful for assessing the LHCD concept in ITER. On the basis of the phenomenology observed during LHCD experiments carried out in different machines, and model of the spectral broadening effect due to parametric instability, an interpretation and possible solution of the related important problem is presented.

  1. Path Integral Monte Carlo Simulation of the Low-Density Hydrogen Plasma B. Militzer y

    E-Print Network [OSTI]

    Militzer, Burkhard

    Path Integral Monte Carlo Simulation of the Low-Density Hydrogen Plasma B. Militzer y Lawrence to calculate the equilibrium properties of hydrogen in the density and temperature range of 9:83 #2; 10 4 #20 surface. We calculate the equation of state and compare with other models for hydrogen valid

  2. PLASMA DYNAMICS AND PLASMA WALL INTERACTION 130 Problems of Atomic Science and Technology. 2006, 6. Series: Plasma Physics (12), p. 130-134

    E-Print Network [OSTI]

    Harilal, S. S.

    PLASMA DYNAMICS AND PLASMA WALL INTERACTION 130 Problems of Atomic Science and Technology. 2006, 6. Series: Plasma Physics (12), p. 130-134 SIMULATION OF HIGH POWER DEPOSITION ON TARGET MATERIALS: APPLICATIONS IN MAGNETIC, INERTIAL FUSION, AND HIGH POWER PLASMA LITHOGRAPHY DEVICES Ahmed Hassanein Argonne

  3. On the breaking of a plasma wave in a thermal plasma. I. The structure of the density singularity

    SciTech Connect (OSTI)

    Bulanov, Sergei V.; Esirkepov, Timur Zh.; Kando, Masaki; Koga, James K.; Pirozhkov, Alexander S.; Nakamura, Tatsufumi [QuBS, Japan Atomic Energy Agency, 1-8-7 Umemidai, Kizugawa, Kyoto 619-0215 (Japan); Bulanov, Stepan S. [University of California, Berkeley, California 94720 (United States); Schroeder, Carl B.; Esarey, Eric [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Califano, Francesco; Pegoraro, Francesco [Physics Department, University of Pisa, Pisa 56127 (Italy)

    2012-11-15T23:59:59.000Z

    The structure of the singularity that is formed in a relativistically large amplitude plasma wave close to the wave breaking limit is found by using a simple waterbag electron distribution function. The electron density distribution in the breaking wave has a typical 'peakon' form. The maximum value of the electric field in a thermal breaking plasma is obtained and compared to the cold plasma limit. The results of computer simulations for different initial electron distribution functions are in agreement with the theoretical conclusions. The after-wavebreak regime is then examined, and a semi-analytical model of the density evolution is constructed. Finally the results of two dimensional particle in cell simulations for different initial electron distribution functions are compared, and the role of thermal effects in enhancing particle injection is noted.

  4. Device and method for electron beam heating of a high density plasma

    DOE Patents [OSTI]

    Thode, Lester E. (Los Alamos, NM)

    1981-01-01T23:59:59.000Z

    A device and method for relativistic electron beam heating of a high density plasma in a small localized region. A relativistic electron beam generator produces a high voltage electron beam which propagates along a vacuum drift tube and is modulated to initiate electron bunching within the beam. The beam is then directed through a low density gas chamber which provides isolation between the vacuum modulator and the relativistic electron beam target. The relativistic beam is then applied to a high density target plasma which typically comprises DT, DD, hydrogen boron or similar thermonuclear gas at a density of 10.sup.17 to 10.sup.20 electrons per cubic centimeter. The target plasma is ionized prior to application of the electron beam by means of a laser or other preionization source. Utilizing a relativistic electron beam with an individual particle energy exceeding 3 MeV, classical scattering by relativistic electrons passing through isolation foils is negligible. As a result, relativistic streaming instabilities are initiated within the high density target plasma causing the relativistic electron beam to efficiently deposit its energy into a small localized region within the high density plasma target.

  5. High Energy Density Science at the Linac Coherent Light Source

    SciTech Connect (OSTI)

    Lee, R W

    2007-10-19T23:59:59.000Z

    High energy density science (HEDS), as a discipline that has developed in the United States from National Nuclear Security Agency (NNSA)-sponsored laboratory research programs, is, and will remain, a major component of the NNSA science and technology strategy. Its scientific borders are not restricted to NNSA. 'Frontiers in High Energy Density Physics: The X-Games of Contemporary Science' identified numerous exciting scientific opportunities in this field, while pointing to the need for a overarching interagency plan for its evolution. Meanwhile, construction of the first x-ray free-electron laser, the Office-of-Science-funded Linear Coherent Light Source-LCLS: the world's first free electron x-ray laser, with 100-fsec time resolution, tunable x-ray energies, a high rep rate, and a 10 order-of-magnitude increase in brightness over any other x-ray source--led to the realization that the scientific needs of NNSA and the broader scientific community could be well served by an LCLS HEDS endstation employing both short-pulse and high-energy optical lasers. Development of this concept has been well received in the community. NNSA requested a workshop on the applicability of LCLS to its needs. 'High Energy Density Science at the LCLS: NNSA Defense Programs Mission Need' was held in December 2006. The workshop provided strong support for the relevance of the endstation to NNSA strategic requirements. The range of science that was addressed covered a wide swath of the vast HEDS phase space. The unique possibilities provided by the LCLS in areas of intense interest to NNSA Defense Programs were discussed. The areas of focus included warm dense matter and equations of state, hot dense matter, and behavior of high-pressure materials under conditions of high strain-rate and extreme dynamic loading. Development of new and advanced diagnostic techniques was also addressed. This report lays out the relevant science, as brief summaries (Ch. II), expanded descriptions (Ch. V), and a more detailed plans for experiments (Ch. VI), highlighting the uniqueness the HEDS endstation will play in providing mission-relevant HED data and in the development of the field. One of the more exciting aspects of NNSA-relevant experiments on LCLS is that, given the extraordinary investment and consequent advances in accurate atomic-scale simulations of matter (to a large extent via the Accelerated Scientific Computing program sponsored by NNSA), the facility will provide a platform that, for the first time, will permit experiments in the regimes of interest at the time and spatial scales of the simulations. In Chapter III, the report places the potential of LCLS with an HED science endstation in the context of science required by NNSA, as well as explicating the relationship of NNSA and HED science in general. Chapter IV discusses 4th-generation light sources, like LCLS, in the context of other laboratory technologies presently utilized by NNSA. The report concludes, noting that an HED endstation on LCLS can provide access to data in regimes that are relevant to NNSA needs but no mechanism exists for providing such data. The endstation will also serve to build a broad-based community in the 'X-Games' of physics. The science generated by the facility will be a collaboration of NNSA-based laboratory scientists and university-based researchers. The LCLS endstation fulfills the need for an intermediate-scale facility capable of delivering fundamental advances and mission-relevant research in high energy density science.

  6. The impact of Hall physics on magnetized high energy density plasma jets

    SciTech Connect (OSTI)

    Gourdain, P.-A.; Seyler, C. E.; Atoyan, L.; Greenly, J. B.; Hammer, D. A.; Kusse, B. R.; Pikuz, S. A.; Potter, W. M.; Schrafel, P. C.; Shelkovenko, T. A. [Cornell University, Ithaca, New York 14853 (United States)] [Cornell University, Ithaca, New York 14853 (United States)

    2014-05-15T23:59:59.000Z

    Hall physics is often neglected in high energy density plasma jets due to the relatively high electron density of such jets (n{sub e}???10{sup 19}?cm{sup ?3}). However, the vacuum region surrounding the jet has much lower densities and is dominated by Hall electric field. This electric field redirects plasma flows towards or away from the axis, depending on the radial current direction. A resulting change in the jet density has been observed experimentally. Furthermore, if an axial field is applied on the jet, the Hall effect is enhanced and ignoring it leads to serious discrepancies between experimental results and numerical simulations. By combining high currents (?1 MA) and magnetic field helicity (15° angle) in a pulsed power generator such as COBRA, plasma jets can be magnetized with a 10?T axial field. The resulting field enhances the impact of the Hall effect by altering the density profile of current-free plasma jets and the stability of current-carrying plasma jets (e.g., Z-pinches)

  7. Science Education Blog | Princeton Plasma Physics Lab

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of ScienceandMesa del Sol HomeFacebook Twitter Principalfuel cells" Find Science DMZ CaseScience

  8. Science Education Lab | Princeton Plasma Physics Lab

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of ScienceandMesa del Sol HomeFacebook Twitter Principalfuel cells" Find Science DMZ CaseScienceLab

  9. Plasma behaviour at high beta and high density in the Madison Symmetric Torus RFP

    SciTech Connect (OSTI)

    Wyman, M. [University of Wisconsin, Madison; Chapman, B. E. [University of Wisconsin, Madison; Ahn, J. W. [University of Wisconsin, Madison; Almagri, A. F. [University of Wisconsin, Madison; Anderson, J. [University of Wisconsin, Madison; Bonomo, F. [Consorzio RFX, Italy; Bower, D L [University of California, Los Angeles; Combs, Stephen Kirk [ORNL; Craig, D. [University of Wisconsin, Madison; Foust, Charles R [ORNL

    2009-01-01T23:59:59.000Z

    Pellet fuelling of improved confinement Madison Symmetric Torus (MST) plasmas has resulted in high density and high plasma beta. The density in improved confinement discharges has been increased fourfold, and a record plasma beta (beta(tot) = 26%) for the improved confinement reversed-field pinch (RFP) has been achieved. At higher beta, a new regime for instabilities is accessed in which local interchange and global tearing instabilities are calculated to be linearly unstable, but experimentally, no severe effect, e. g., a disruption, is observed. The tearing instability, normally driven by the current gradient, is driven by the pressure gradient in this case, and there are indications of increased energy transport ( as compared with low-density improved confinement). Pellet fuelling is also compared with enhanced edge fuelling of standard confinement RFP discharges for the purpose of searching for a density limit in MST. In standard-confinement discharges, pellet fuelling peaks the density profile where edge fuelling cannot, but transport appears unchanged. For a limited range of plasma current, MST discharges with edge fuelling are constrained to a maximum density corresponding to the Greenwald limit. This limit is surpassed in pellet-fuelled improved confinement discharges.

  10. High Energy Density Laboratory Plasmas Program | National Nuclear Security

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC) EnvironmentalGyroSolé(tm) Harmonicbet WhenHiggs Boson May Be

  11. High Energy Density Laboratory Plasmas | National Nuclear Security

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC) EnvironmentalGyroSolé(tm) Harmonicbet WhenHiggs Boson May BeAdministration |

  12. Science Education Group | Princeton Plasma Physics Lab

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's PossibleRadiationImplementingnpitcheResearch BriefsTenney, Office ofScience Education Group View

  13. IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 34, NO. 3, JUNE 2006 755 Nonequilibrium EEDF in Gas Discharge Plasmas

    E-Print Network [OSTI]

    Kaganovich, Igor

    ­ion creation and gas excitation are due to the impact of fast elec- trons in the plasma volume, while electron discharges. This paper is organized as follows. Basic processes in gas dis- charge plasmas when EEDF and thusIEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 34, NO. 3, JUNE 2006 755 Nonequilibrium EEDF in Gas

  14. 2048 IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 30, NO. 5, OCTOBER 2002 Plasma Molding Over Surface Topography

    E-Print Network [OSTI]

    Economou, Demetre J.

    model was developed to study plasma "molding" over surface topography. The radio frequency (RF) sheath2048 IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 30, NO. 5, OCTOBER 2002 Plasma Molding Over Surface Topography: Simulation of Ion Flow, and Energy and Angular Distributions Over Steps in RF High

  15. 518 IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 33, NO. 2, APRIL 2005 Plasma Dynamics During Breakdown in

    E-Print Network [OSTI]

    Kushner, Mark

    518 IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 33, NO. 2, APRIL 2005 Plasma Dynamics During November 7, 2004. Work supported in part by National Science Foundation CTS03-15353 and in part Breakdown in an HID Lamp Ananth N. Bhoj and Mark J. Kushner, Fellow, IEEE Abstract--Large starting voltages

  16. Nonlocal theory of electromagnetic wave decay into two electromagnetic waves in a rippled density plasma channel

    SciTech Connect (OSTI)

    Sati, Priti; Tripathi, V. K. [Indian Institute of Technology, Hauz Khas, Delhi 110054 (India)

    2012-12-15T23:59:59.000Z

    Parametric decay of a large amplitude electromagnetic wave into two electromagnetic modes in a rippled density plasma channel is investigated. The channel is taken to possess step density profile besides a density ripple of axial wave vector. The density ripple accounts for the momentum mismatch between the interacting waves and facilitates nonlinear coupling. For a given pump wave frequency, the requisite ripple wave number varies only a little w.r.t. the frequency of the low frequency decay wave. The radial localization of electromagnetic wave reduces the growth rate of the parametric instability. The growth rate decreases with the frequency of low frequency electromagnetic wave.

  17. Computational Science and Engineering Certification for Nuclear, Plasma, and Radiological Engineering

    E-Print Network [OSTI]

    Gilbert, Matthew

    Computational Science and Engineering Certification for Nuclear, Plasma, and Radiological Engineering The Computational Science and Engineering certificate program is designed to provide NPRE a certificate in "Computational Science and Engineering", students must complete the required courses listed

  18. Science Education Programs | Princeton Plasma Physics Lab

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of ScienceandMesa del Sol HomeFacebook Twitter Principalfuel cells" Find Science DMZ

  19. Science Education | Princeton Plasma Physics Lab

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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  20. Science literacy | Princeton Plasma Physics Lab

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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  1. Science Education | Princeton Plasma Physics Lab

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOnItemResearch > TheNuclearHomeland Science Stockpile2015 Annual Conference About

  2. MIT Plasma Science & Fusion Center

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC)Integrated Codes |IsLove Your Home and It'll Love You Back LoveM od BeforeMira,

  3. MIT Plasma Science & Fusion Center

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC)Integrated Codes |IsLove Your Home and It'll Love You Back LoveM od

  4. Photoemission rate of strongly interacting quark-gluon plasma at finite density

    SciTech Connect (OSTI)

    Jo, Kwanghyun; Sin, Sang-Jin [Department of Physics, Hanyang University, Seoul 133-791 (Korea, Republic of)

    2011-01-15T23:59:59.000Z

    We calculate the thermal spectral function of strongly interacting Yang-Mills plasma with finite density using the holographic technique. The gravity dual of the finite temperature and density is taken as the Reissner-Nordstroem-anti-de Sitter black hole. In the presence of charge, linearized vector modes of gravitational and electromagnetic perturbation are coupled with each other. By introducing master variables for these modes, we solve the coupled system and calculate spectral function. The spectral function gets a new peak due to the density effect, which is most dramatic in the momentum plot with fixed frequency. We also calculate the photoemission rate of our gauge theory plasma from the spectral function for lightlike momentum. AC, dc conductivity, and their density dependence is also computed.

  5. The formation of reverse shocks in magnetized high energy density supersonic plasma flows

    SciTech Connect (OSTI)

    Lebedev, S. V., E-mail: s.lebedev@imperial.ac.uk, E-mail: l.suttle10@imperial.ac.uk; Suttle, L.; Swadling, G. F.; Bennett, M.; Bland, S. N.; Burdiak, G. C.; Chittenden, J. P.; Grouchy, P. de; Hall, G. N.; Hare, J. D.; Kalmoni, N.; Niasse, N.; Patankar, S.; Smith, R. A.; Suzuki-Vidal, F. [Blackett Laboratory, Imperial College, London SW7 2BW (United Kingdom)] [Blackett Laboratory, Imperial College, London SW7 2BW (United Kingdom); Burgess, D.; Clemens, A. [Astronomy Unit, School of Physics and Astronomy, Queen Mary University of London, London E1 4NS (United Kingdom)] [Astronomy Unit, School of Physics and Astronomy, Queen Mary University of London, London E1 4NS (United Kingdom); Ciardi, A. [LERMA, Observatoire de Paris and École Normale Supérieure Université Pierre et Marie Curie, UMR 8112 CNRS, 75231 Paris (France)] [LERMA, Observatoire de Paris and École Normale Supérieure Université Pierre et Marie Curie, UMR 8112 CNRS, 75231 Paris (France); Sheng, L. [Blackett Laboratory, Imperial College, London SW7 2BW (United Kingdom) [Blackett Laboratory, Imperial College, London SW7 2BW (United Kingdom); Northwest Institute of Nuclear Technology, Xi'an 710024 (China); Yuan, J. [Blackett Laboratory, Imperial College, London SW7 2BW (United Kingdom) [Blackett Laboratory, Imperial College, London SW7 2BW (United Kingdom); Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang 621900 (China); and others

    2014-05-15T23:59:59.000Z

    A new experimental platform was developed, based on the use of supersonic plasma flow from the ablation stage of an inverse wire array z-pinch, for studies of shocks in magnetized high energy density physics plasmas in a well-defined and diagnosable 1-D interaction geometry. The mechanism of flow generation ensures that the plasma flow (Re{sub M}???50, M{sub S}???5, M{sub A}???8, V{sub flow}???100?km/s) has a frozen-in magnetic field at a level sufficient to affect shocks formed by its interaction with obstacles. It is found that in addition to the expected accumulation of stagnated plasma in a thin layer at the surface of a planar obstacle, the presence of the magnetic field leads to the formation of an additional detached density jump in the upstream plasma, at a distance of ?c/?{sub pi} from the obstacle. Analysis of the data obtained with Thomson scattering, interferometry, and local magnetic probes suggests that the sub-shock develops due to the pile-up of the magnetic flux advected by the plasma flow.

  6. Effect of electron density profile on power absorption of high frequency electromagnetic waves in plasma

    SciTech Connect (OSTI)

    Xi Yanbin; Liu Yue [MOE Key Laboratory of Materials Modification by Laser, Electron, and Ion Beams, School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China)

    2012-07-15T23:59:59.000Z

    Considering different typical electron density profiles, a multi slab approximation model is built up to study the power absorption of broadband (0.75-30 GHz) electromagnetic waves in a partially ionized nonuniform magnetized plasma layer. Based on the model, the power absorption spectra for six cases are numerically calculated and analyzed. It is shown that the absorption strongly depends on the electron density fluctuant profile, the background electron number density, and the collision frequency. A potential optimum profile is also analyzed and studied with some particular parameters.

  7. E?H mode transition density and power in two types of inductively coupled plasma configuration

    SciTech Connect (OSTI)

    Wang, Jian; Du, Yin-chang; Zhang, Xiao; Zheng, Zhe; Liu, Yu; Xu, Liang; Wang, Pi; Cao, Jin-xiang, E-mail: jxcao@ustc.edu.cn [Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China)

    2014-07-15T23:59:59.000Z

    E???H transition power and density were investigated at various argon pressures in inductively coupled plasma (ICP) in a cylindrical interlaid chamber. The transition power versus the pressure shows a minimum transition power at 4?Pa (?/?=1) for argon. Then the transition density hardly changes at low pressures (?/??1), but it increases clearly when argon pressure exceeds an appropriate value. In addition, both the transition power and transition density are lower in the re-entrant configuration of ICP compared with that in the cylindrical configuration of ICP. The result may be caused from the decrease of stochastic heating in the re-entrant configuration of ICP. This work is useful to understand E???H mode transition and control the transition points in real plasma processes.

  8. Plasma density accumulation on a conical surface for diffusion along a diverging magnetic field

    SciTech Connect (OSTI)

    Saha, S. K.; Chowdhury, S.; Janaki, M. S.; Ghosh, A.; Hui, A. K.; Raychaudhuri, S. [Saha Institute of Nuclear Physics, Plasma Physics Division, 1/AF Bidhannagar, Kolkata 700064 (India)] [Saha Institute of Nuclear Physics, Plasma Physics Division, 1/AF Bidhannagar, Kolkata 700064 (India)

    2014-04-15T23:59:59.000Z

    Two-dimensional (2-D) density and potential measurements have been carried out for plasma diffusing through an aperture in a diverging magnetic field. The radial density profile near the source is peaked on the axis but gradually evolves into a hollow profile away from the source. We observe a slow increase of the peak density along a hollow conical surface and correlate with the 2-D potential measurement reported earlier. It is also shown that the formation of 2-D structures with similar features are observed whenever plasma is allowed to diffuse through a physical aperture in such diverging magnetic field configuration, with or without the presence of electric double layer, i.e., the phenomenon is generic in nature.

  9. Shock waves in a Z-pinch and the formation of high energy density plasma

    SciTech Connect (OSTI)

    Rahman, H. U. [Magneto-Inertial Fusion Technologies Inc. (MIFTI), Irvine, California 92612 (United States) and Department of Physics, University of California Irvine, Irvine, California 92697 (United States); Wessel, F. J. [Department of Physics, University of California Irvine, Irvine California 92697 (United States); Ney, P. [Mount San Jacinto College, Menifee, California 92584 (United States); Presura, R. [University of Nevada, Reno, 1664 N. Virginia St., Reno, Nevada 89557-0208 (United States); Ellahi, Rahmat [Department of Mathematics and Statistics, FBAS, IIU, Islamabad (Pakistan) and Department of Mechanical Engineering, University of California Riverside, Riverside, California 92521 (United States); Shukla, P. K. [Department of Mechanical and Aerospace Engineering and Center for Energy Research, University of California San Diego, La Jolla, California 92093 (United States)

    2012-12-15T23:59:59.000Z

    A Z-pinch liner, imploding onto a target plasma, evolves in a step-wise manner, producing a stable, magneto-inertial, high-energy-density plasma compression. The typical configuration is a cylindrical, high-atomic-number liner imploding onto a low-atomic-number target. The parameters for a terawatt-class machine (e.g., Zebra at the University of Nevada, Reno, Nevada Terawatt Facility) have been simulated. The 2-1/2 D MHD code, MACH2, was used to study this configuration. The requirements are for an initial radius of a few mm for stable implosion; the material densities properly distributed, so that the target is effectively heated initially by shock heating and finally by adiabatic compression; and the liner's thickness adjusted to promote radial current transport and subsequent current amplification in the target. Since the shock velocity is smaller in the liner, than in the target, a stable-shock forms at the interface, allowing the central load to accelerate magnetically and inertially, producing a magneto-inertial implosion and high-energy density plasma. Comparing the implosion dynamics of a low-Z target with those of a high-Z target demonstrates the role of shock waves in terms of compression and heating. In the case of a high-Z target, the shock wave does not play a significant heating role. The shock waves carry current and transport the magnetic field, producing a high density on-axis, at relatively low temperature. Whereas, in the case of a low-Z target, the fast moving shock wave preheats the target during the initial implosion phase, and the later adiabatic compression further heats the target to very high energy density. As a result, the compression ratio required for heating the low-Z plasma to very high energy densities is greatly reduced.

  10. Effects of a random spatial variation of the plasma density on the mode conversion in cold, unmagnetized, and stratified plasmas

    SciTech Connect (OSTI)

    Jung Yu, Dae [School of Space Research, Kyung Hee University, Yongin 446-701 (Korea, Republic of)] [School of Space Research, Kyung Hee University, Yongin 446-701 (Korea, Republic of); Kim, Kihong [Department of Energy Systems Research, Ajou University, Suwon 443-749 (Korea, Republic of)] [Department of Energy Systems Research, Ajou University, Suwon 443-749 (Korea, Republic of)

    2013-12-15T23:59:59.000Z

    We study the effects of a random spatial variation of the plasma density on the mode conversion of electromagnetic waves into electrostatic oscillations in cold, unmagnetized, and stratified plasmas. Using the invariant imbedding method, we calculate precisely the electromagnetic field distribution and the mode conversion coefficient, which is defined to be the fraction of the incident wave power converted into electrostatic oscillations, for the configuration where a numerically generated random density variation is added to the background linear density profile. We repeat similar calculations for a large number of random configurations and take an average of the results. We obtain a peculiar nonmonotonic dependence of the mode conversion coefficient on the strength of randomness. As the disorder increases from zero, the maximum value of the mode conversion coefficient decreases initially, then increases to a maximum, and finally decreases towards zero. The range of the incident angle in which mode conversion occurs increases monotonically as the disorder increases. We present numerical results suggesting that the decrease of mode conversion mainly results from the increased reflection due to the Anderson localization effect originating from disorder, whereas the increase of mode conversion of the intermediate disorder regime comes from the appearance of many resonance points and the enhanced tunneling between the resonance points and the cutoff point. We also find a very large local enhancement of the magnetic field intensity for particular random configurations. In order to obtain high mode conversion efficiency, it is desirable to restrict the randomness close to the resonance region.

  11. Spatially resolvable optical emission spectrometer for analyzing density uniformity of semiconductor process plasma

    SciTech Connect (OSTI)

    Oh, Changhoon; Ryoo, Hoonchul; Lee, Hyungwoo; Hahn, Jae W. [Nano Photonics Laboratory, School of Mechanical Engineering, Yonsei University, 134 Sinchon-dong, Seodaemun-gu, Seoul 120-749 (Korea, Republic of); Kim, Se-Yeon; Yi, Hun-Jung [Manufacturing Technology Team, Memory Division, Semiconductor Business, Samsung Electronics, Hwasung-City, Gyeonggi-do 445-701 (Korea, Republic of)

    2010-10-15T23:59:59.000Z

    We proposed a spatially resolved optical emission spectrometer (SROES) for analyzing the uniformity of plasma density for semiconductor processes. To enhance the spatial resolution of the SROES, we constructed a SROES system using a series of lenses, apertures, and pinholes. We calculated the spatial resolution of the SROES for the variation of pinhole size, and our calculated results were in good agreement with the measured spatial variation of the constructed SROES. The performance of the SROES was also verified by detecting the correlation between the distribution of a fluorine radical in inductively coupled plasma etch process and the etch rate of a SiO{sub 2} film on a silicon wafer.

  12. Generation of terahertz radiation from a low-density plasma slab irradiated by a laser pulse

    SciTech Connect (OSTI)

    Frolov, A. A. [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation)

    2010-04-15T23:59:59.000Z

    The generation of terahertz electromagnetic radiation when a laser pulse propagates through a low-density plasma slab is considered. It is shown that terahertz waves are excited because of the growth of a weakly damped, antisymmetric leaking mode of the plasma slab. The spectral, angular, and energy parameters of the terahertz radiation are investigated, as well as the spatiotemporal structure of the emitted waves. It is demonstrated that terahertz electromagnetic wave fields are generated most efficiently when the pulse length is comparable to the slab thickness.

  13. IOP PUBLISHING PLASMA SOURCES SCIENCE AND TECHNOLOGY Plasma Sources Sci. Technol. 18 (2009) 045003 (6pp) doi:10.1088/0963-0252/18/4/045003

    E-Print Network [OSTI]

    such an electrodeless plasma centrifuge. First we will summarize advantages of the plasma centrifuge over the gasIOP PUBLISHING PLASMA SOURCES SCIENCE AND TECHNOLOGY Plasma Sources Sci. Technol. 18 (2009) 045003 (6pp) doi:10.1088/0963-0252/18/4/045003 Wave-driven countercurrent plasma centrifuge Abraham J

  14. Experimental and Computational Studies of High Energy Density Plasma Streams Ablated from Fine Wires

    SciTech Connect (OSTI)

    Greenly, John B. [Cornell University; Seyler, Charles [Cornell University

    2014-03-30T23:59:59.000Z

    Experimental and computational studies of high energy density plasma streams ablated from fine wires. Laboratory of Plasma Studies, School of Electrical and Computer Engineering, Cornell University. Principal Investigators: Dr. John B. Greenly and Dr. Charles E. Seyler. This report summarizes progress during the final year of this project to study the physics of high energy density (HED) plasma streams of 10^17-10^20/cm3 density and high velocity (~100-500 km/s). Such streams are produced from 5-250 micrometer diameter wires heated and ionized by a 1 MA, 250 ns current pulse on the COBRA pulsed power facility at Cornell University. Plasma is ablated from the wires and is driven away to high velocity by unbalanced JxB force. A wire, or an array of wires, can persist as an essentially stationary, continuous source of this streaming plasma for >200 ns, even with driving magnetic fields of many Tesla and peak current densities in the plasma of many MA/cm2. At the heart of the ablation stream generation is the continuous transport of mass from the relatively cold, near-solid-density wire "core" into current-carrying plasma within 1 mm of the wire, followed by the magnetic acceleration of that plasma and its trapped flux to form a directed stream. In the first two years of this program, an advancing understanding of ablation physics led to the discovery of several novel wire ablation experimental regimes. In the final year, one of these new HED plasma regimes has been studied in quantitative detail. This regime studies highly reproducible magnetic reconnection in strongly radiating plasma with supersonic and superalfvenic flow, and shock structures in the outflow. The key discovery is that very heavy wires, e.g. 250 micrometer diameter Al or 150 micrometer Cu, behave in a qualitatively different way than the lighter wires typically used in wire-array Z-pinches. Such wires can be configured to produce a static magnetic X-point null geometry that stores magnetic and thermal energy; reconnection and outflow are triggered when the current begins to decrease and the electric field reverses. The reconnecting flow is driven by both magnetic and thermal pressure forces, and it has been found to be possible to vary the configuration so that one or the other dominates. The magnetic null extends into a current sheet that is heated and radiates strongly, with supersonic outflows. This is the first study of reconnection in this HED plasma regime. This compressible, radiative regime, and the triggering mechanism, may be relevant to solar and astrophysical processes. The PERSEUS extended MHD code has been developed for simulation of these phenomena, and will continue to be used and further developed to help interpret and understand experimental results, as well as to guide experimental design. The code is well-suited to simulations of shocks, and includes Hall and electron inertia physics that appear to be of importance in a number of ablation flow regimes, and definitely in the reconnection regime when gradient scales are comparable to the ion inertial scale. During the final year, our graduate student supported by this grant completed a new version of PERSEUS with the finite volume computational scheme replaced by a discontinuous Galerkin method that gives much less diffusive behavior and allows faster run time and higher spatial resolution. Thecode is now being used to study shock structures produced in the outflow region of the reconnection regime.

  15. Current initiation in low-density foam z-pinch plasmas

    SciTech Connect (OSTI)

    Derzon, M.; Nash, T.; Allshouse, G. [and others

    1996-07-01T23:59:59.000Z

    Low density agar and aerogel foams were tested as z-pinch loads on the SATURN accelerator. In these first experiments, we studied the initial plasma conditions by measuring the visible emission at early times with a framing camera and 1-D imaging. At later time, near the stagnation when the plasma is hotter, x-ray imaging and spectral diagnostics were used to characterize the plasma. Filamentation and arcing at the current contacts was observed. None of the implosions were uniform along the z-axis. The prime causes of these problems are believed to be the electrode contacts and the current return configuration and these are solvable. Periodic phenomena consistent with the formation of instabilities were observed on one shot, not on others, implying that there may be a way of controlling instabilities in the pinch. Many of the issues involving current initiation may be solvable. Solutions are discussed.

  16. Generation of high order optical harmonics in steep plasma density gradients

    SciTech Connect (OSTI)

    Linde, D. von der [Institut fuer Laser- und Plasmaphysik, Universitaet Essen, D-45117 Essen (Germany)

    1998-02-20T23:59:59.000Z

    During the interaction of an intense ultrashort laser pulse with solid targets a thin layer of surface plasma is generated in which the density drops to the vacuum level in a distance much shorter than the wavelength. This sharp plasma-vacuum boundary performs an oscillatory motion in response to the electromagnetic forces of the intense laser light. It is shown that the generation of reflected harmonics can be interpreted as a phase modulation experienced by the light upon reflection from the oscillating boundary. The modulation sidebands of the reflected frequency spectrum correspond to odd and even harmonics of the laser frequency. Retardation effects lead to a strong anharmonicity for high velocities of the plasma-vacuum boundary. As a result, harmonic generation is strongly enhanced in the relativistic regime of laser intensities.

  17. Electron density and temperature measurement by continuum radiation emitted from weakly ionized atmospheric pressure plasmas

    SciTech Connect (OSTI)

    Park, Sanghoo; Choe, Wonho, E-mail: wchoe@kaist.ac.kr [Department of Physics, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Youn Moon, Se [High-enthalpy Plasma Research Center, Chonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju 561-756 (Korea, Republic of); Park, Jaeyoung [5771 La Jolla Corona Drive, La Jolla, CA 92037 (United States)

    2014-02-24T23:59:59.000Z

    The electron-atom neutral bremsstrahlung continuum radiation emitted from weakly ionized plasmas is investigated for electron density and temperature diagnostics. The continuum spectrum in 450–1000?nm emitted from the argon atmospheric pressure plasma is found to be in excellent agreement with the neutral bremsstrahlung formula with the electron-atom momentum transfer cross-section given by Popovi?. In 280–450?nm, however, a large discrepancy between the measured and the neutral bremsstrahlung emissivities is observed. We find that without accounting for the radiative H{sub 2} dissociation continuum, the temperature, and density measurements would be largely wrong, so that it should be taken into account for accurate measurement.

  18. Heavy ion fusion science research for high energy density physics and fusion applications

    E-Print Network [OSTI]

    Logan, B.G.

    2007-01-01T23:59:59.000Z

    drive targets for inertial fusion energy. 1. Introduction Adensity matter and fusion energy. Previously, experiments inHeavy ion fusion science research for high energy density

  19. Quasilinear dynamics of a cloud of hot electrons propagating through a plasma with decreasing density and temperature

    SciTech Connect (OSTI)

    Foroutan, G. [Department of Physics, Faculty of Science, Sahand University of Technology, Tabriz 51335-1996 (Iran, Islamic Republic of); School of Physics, The University of Sydney, Sydney NSW 2006 (Australia); Khalilpour, H.; Moslehi-Fard, M. [Faculty of Physics, Tabriz University, Tabriz 51664 (Iran, Islamic Republic of); Li, B.; Robinson, P. A. [School of Physics, University of Sydney, Sydney NSW 2006 (Australia)

    2008-12-15T23:59:59.000Z

    The effects of plasma inhomogeneities on the propagation of a cloud of hot electrons through a cold background plasma and generation of Langmuir waves are investigated using numerical simulations of the quasilinear equations. It is found that in a plasma with decreasing density the quasilinear relaxation of the electron distribution in velocity space is accelerated and the levels of the generated Langmuir waves are enhanced. The magnitude of the induced emission rate is increased and its maximum value moves to lower velocities. Due to density gradient the height of plateau shows an increase at small distances and a corresponding decrease at large distances. It is also found that in a plasma with decreasing temperature, the relaxation of the beam is retarded, the spectral density of Langmuir waves is broadened, and the height of the plateau decreases below its value in a uniform plasma. In the presence of both density and temperature gradients, at given position, the height and upper boundary of the plateau and the level of Langmuir waves are all increased at small velocities. The spatial expansion of the beam is increased by the plasma inhomogeneities, but its average velocity of propagation decreases. Initially, at a given position, the velocity at the upper boundary of the plateau is smaller in the presence of the density gradient than in the uniform plasma but the reverse is true at longer times. Due to temperature gradient, at large times and small distances, the upper boundary of the plateau is increased above its value in the uniform plasma. Because of fast relaxation, the value of the lower boundary of the plateau in the plasma with decreasing density is always less than its value in the uniform plasma. It is found that the local velocity of the beam decreases when the density gradient is present. The local velocity spread of the beam remains unchanged during the propagation of the beam in the uniform plasma, but increases in the presence of inhomogeneities.

  20. Wavelet-based density estimation for noise reduction in plasma simulations using particles

    SciTech Connect (OSTI)

    Nguyen van yen, Romain [Laboratoire de Meteorologie Dynamique-CNRL, Ecole Normale Superieure; Del-Castillo-Negrete, Diego B [ORNL; Schneider, Kai [Universite d'Aix-Marseille; Farge, Marie [Laboratoire de Meteorologie Dynamique-CNRL, Ecole Normale Superieure; Chen, Guangye [ORNL

    2010-01-01T23:59:59.000Z

    For given computational resources, one of the main limitations in the accuracy of plasma simulations using particles comes from the noise due to limited statistical sampling in the reconstruction of the particle distribution function. A method based on wavelet multiresolution analysis is proposed and tested to reduce this noise. The method, known as wavelet based density estimation (WBDE), was previously introduced in the statistical literature to estimate probability densities given a nite number of independent measurements. Its novel application to plasma simulations can be viewed as a natural extension of the nite size particles (FSP) approach, with the advantage of estimating more accurately distribution functions that have localized sharp features. The proposed method preserves the moments of the particle distribution function to a good level of accuracy, has no constraints on the dimensionality of the system, does not require an a priori selection of a global smoothing scale, and its able to adapt locally to the smoothness of the density based on the given discrete particle data. Most importantly, the computational cost of the denoising stage is of the same order as one timestep of a FSP simulation. The method is compared with a recently proposed proper orthogonal decomposition based method, and it is tested with particle data corresponding to strongly collisional, weakly collisional, and collisionless plasmas simulations.

  1. Metrology Challenges for High Energy Density Science Target Manufacture

    SciTech Connect (OSTI)

    Seugling, R M; Bono, M J; Davis, P

    2009-02-19T23:59:59.000Z

    Currently, High Energy Density Science (HEDS) experiments are used to support and qualify predictive physics models. These models assume ideal conditions such as energy (input) and device (target) geometry. The experiments rely on precision targets constructed from components with dimensions in the millimeter range, while having micrometer-scale, functional features, including planar steps, sine waves, and step-joint geometry on hemispherical targets. Future target designs will likely have features and forms that rival or surpass current manufacturing and characterization capability. The dimensional metrology of these features is important for a number of reasons, including qualification of sub-components prior to assembly, quantification of critical features on the as-built assemblies and as a feedback mechanism for fabrication process development. Variations in geometry from part to part can lead to functional limitations, such as unpredictable instabilities during an experiment and the inability to assemble a target from poorly matched sub-components. Adding to the complexity are the large number and variety of materials, components, and shapes that render any single metrology technique difficult to use with low uncertainty. Common materials include metal and glass foams, doped transparent and opaque plastics and a variety of deposited and wrought metals. A suite of metrology tools and techniques developed to address the many critical issues relevant to the manufacture of HEDS targets including interferometry, x-ray radiography and contact metrology are presented including two sided interferometry for absolute thickness metrology and low force probe technology for micrometer feature coordinate metrology.

  2. IEEE TRANSACTIONSON PLASMA SCIENCE,VOL. 21, NO. 1, FEBRUARY 1993 Phase-Matched Third Harmonic

    E-Print Network [OSTI]

    IEEE TRANSACTIONSON PLASMA SCIENCE,VOL. 21, NO. 1, FEBRUARY 1993 ~ 105 Phase-Matched Third Harmonic Generation in a Plasma J. M. Rax and N. J. Fisch Abstract-Relativistic third harmonic generationin a plasma is investigated. The growth of a third harmonic wave is limited by the difference between the phase velocity

  3. A US Strategy to Explore the Science and Technology of Energy-Producing Plasmas

    E-Print Network [OSTI]

    1 A US Strategy to Explore the Science and Technology of Energy-Producing Plasmas Discussion Draft strategy to explore the science and technology of energy-producing plasmas must change in the post September 16, 1997 Introduction Last year, the Department of Energy redirected the fusion program from

  4. Effect of low density H-mode operation on edge and divertor plasma parameters

    SciTech Connect (OSTI)

    Maingi, R. [Oak Ridge Associated Universities, Inc., TN (United States); Mioduszewski, P.K. [Oak Ridge National Lab., TN (United States); Cuthbertson, J.W. [Sandia National Labs., Albuquerque, NM (United States)] [and others

    1994-07-01T23:59:59.000Z

    We present a study of the impact of H-mode operation at low density on divertor plasma parameters on the DIII-D tokamak. The line-average density in H-mode was scanned by variation of the particle exhaust rate, using the recently installed divertor cryo-condensation pump. The maximum decrease (50%) in line-average electron density was accompanied by a factor of 2 increase in the edge electron temperature, and 10% and 20% reductions in the measured core and divertor radiated power, respectively. The measured total power to the inboard divertor target increased by a factor of 3, with the major contribution coming from a factor of 5 increase in the peak heat flux very close to the inner strike point. The measured increase in power at the inboard divertor target was approximately equal to the measured decrease in core and divertor radiation.

  5. COLD BUBBLE FORMATION DURING TOKAMAK DENSITY LIMIT DISRUPTIONS

    E-Print Network [OSTI]

    Howard, John

    COLD BUBBLE FORMATION DURING TOKAMAK DENSITY LIMIT DISRUPTIONS J. HOWARD, M. PERSSON* Plasma Research Laboratory, Research School of Physical Sciences, Australian National University, Canberra

  6. Organization by Gordon Research Conferences of the 2012 Plasma Processing Science Conference 22-27 July 2012

    SciTech Connect (OSTI)

    Jane Chang

    2012-07-27T23:59:59.000Z

    The 2012 Gordon Research Conference on Plasma Processing Science will feature a comprehensive program that will highlight the most cutting edge scientific advances in plasma science and technology as well as explore the applications of this nonequilibrium medium in possible approaches relative to many grand societal challenges. Fundamental science sessions will focus on plasma kinetics and chemistry, plasma surface interactions, and recent trends in plasma generation and multi-phase plasmas. Application sessions will explore the impact of plasma technology in renewable energy, the production of fuels from renewable feedstocks and carbon dioxide neutral solar fuels (from carbon dioxide and water), and plasma-enabled medicine and sterilization.

  7. Application of soft X-ray lasers for probing high density plasmas

    SciTech Connect (OSTI)

    Da Silva, L.B.; Barbee, T.W. Jr.; Cauble, R. [and others

    1996-08-01T23:59:59.000Z

    The reliability and characteristics of collisionally pumped soft x-ray lasers make them ideal for a wide variety of plasma diagnostics. These systems now operate over a wavelength range extending from 35 to 400 {Angstrom} and have output energies as high as 10 mJ in 150 ps pulses. The beam divergence of these lasers is less than 15 mrad and they have a typical linewidth of {Delta}{lambda}/{lambda} {approximately} 10{sup -4} making them the brightest xuv sources available. In this paper we will describe the use of x-ray lasers to probe high density plasmas using a variety of diagnostic techniques. Using an x-ray laser and a multilayer mirror imaging system we have studied hydrodynamic imprinting of laser speckle pattern on directly driven thin foils with 1-2 {mu}m spatial resolution. Taking advantage of recently developed multilayer beamsplitters we have constructed and used a Mach-Zehnder interferometer operating at 155 {Angstrom} to probe 1-3 mm size laser produced plasmas with peak electron densities of 4 x 10{sup 21} cm{sup -3}. A comparison of our results with computer simulations will be presented.

  8. A comparison of parametric decay of oblique Langmuir wave in high and low density magneto-plasmas

    SciTech Connect (OSTI)

    Shahid, M.; Hussain, A. [Salam Chair in Physics, Government College University, Lahore-54000 (Pakistan) [Salam Chair in Physics, Government College University, Lahore-54000 (Pakistan); Department of Physics, Government College University, Lahore-54000 (Pakistan); Murtaza, G. [Salam Chair in Physics, Government College University, Lahore-54000 (Pakistan)] [Salam Chair in Physics, Government College University, Lahore-54000 (Pakistan)

    2013-09-15T23:59:59.000Z

    The parametric decay instability of an obliquely propagating Langmuir wave into the low-frequency electromagnetic shear Alfven wave and the Left-Handed Circularly Polarized wave has been investigated in an electron-ion plasma, immersed in a uniform external magnetic field. Quantum magneto-hydrodynamic model has been used to find the linear and non-linear response of a high density quantum magneto-plasma. Going to the classical limit (??0) retrieves the results for low density classical plasma. Nonlinear dispersion relations and growth rates are derived with analytically and numerically. It is observed that growth rate in the high density degenerate magneto-plasma increases exponentially, while in the low density classical case it increases logarithmically.

  9. Device and method for relativistic electron beam heating of a high-density plasma to drive fast liners

    DOE Patents [OSTI]

    Thode, Lester E. (Los Alamos, NM)

    1981-01-01T23:59:59.000Z

    A device and method for relativistic electron beam heating of a high-density plasma in a small localized region. A relativistic electron beam generator or accelerator produces a high-voltage electron beam which propagates along a vacuum drift tube and is modulated to initiate electron bunching within the beam. The beam is then directed through a low-density gas chamber which provides isolation between the vacuum modulator and the relativistic electron beam target. The relativistic beam is then applied to a high-density target plasma which typically comprises DT, DD, hydrogen boron or similar thermonuclear gas at a density of 10.sup.17 to 10.sup.20 electrons per cubic centimeter. The target gas is ionized prior to application of the electron beam by means of a laser or other preionization source to form a plasma. Utilizing a relativistic electron beam with an individual particle energy exceeding 3 MeV, classical scattering by relativistic electrons passing through isolation foils is negligible. As a result, relativistic streaming instabilities are initiated within the high-density target plasma causing the relativistic electron beam to efficiently deposit its energy and momentum into a small localized region of the high-density plasma target. Fast liners disposed in the high-density target plasma are explosively or ablatively driven to implosion by a heated annular plasma surrounding the fast liner which is generated by an annular relativistic electron beam. An azimuthal magnetic field produced by axial current flow in the annular plasma, causes the energy in the heated annular plasma to converge on the fast liner.

  10. Highly Resolved Self-Excited Density Waves in a Complex Plasma

    SciTech Connect (OSTI)

    Schwabe, M.; Rubin-Zuzic, M.; Zhdanov, S.; Thomas, H. M.; Morfill, G. E. [Max-Planck-Institut fuer extraterrestrische Physik, D-85740 Garching (Germany)

    2007-08-31T23:59:59.000Z

    Experimental results on self-excited density waves in a complex plasma are presented. An argon plasma is produced in a capacitively coupled rf discharge at a low power and gas pressure. A cloud of microparticles is subjected to effective gravity in the range of 1-4 g by thermophoresis. The cloud is stretched horizontally (width/height {approx_equal}45 mm/8 mm). The critical pressure for the onset of the waves increases with the temperature gradient. The waves are propagating in the direction of the ion drift. The wave frequency, phase velocity, and wavelength are measured, and particle migrations affected by the waves are analyzed at a time scale of 1 ms/frame and a subpixel space resolution.

  11. Test particle simulation of direct laser acceleration in a density-modulated plasma waveguide

    SciTech Connect (OSTI)

    Lin, M.-W.; Jovanovic, I. [Department of Mechanical and Nuclear Engineering, Pennsylvania State University, University Park, Pennsylvania 16802 (United States)

    2012-11-15T23:59:59.000Z

    Direct laser acceleration (DLA) of electrons by the use of the intense axial electric field of an ultrafast radially polarized laser pulse is a promising technique for future compact accelerators. Density-modulated plasma waveguides can be implemented for guiding the propagation of the laser pulse to extend the acceleration distance and for the quasi-phase-matching between the accelerated electrons and the laser pulse. A test particle model is developed to study the optimal axial density modulation structure of plasma waveguides for laser pulses to efficiently accelerate co-propagating electrons. A simple analytical approach is also presented, which can be used to estimate the energy gain in DLA. The analytical model is validated by the test particle simulation. The effect of injection phase and acceleration of electrons injected at various radial positions are studied. The results indicate that a positively chirped density modulation of the waveguide structure is required to accelerate electron with low initial energies, and can be effectively optimized. A wider tolerance on the injection phase and radial distance from the waveguide axis exists for electrons injected with a higher initial energy.

  12. Efficient plasma production by intense laser irradiation of low density foam targets

    SciTech Connect (OSTI)

    Tripathi, S.; Chaurasia, S.; Munda, D. S.; Gupta, N. K.; Dhareshwar, L. J. [Laser and Neutron Physics Division, Bhabha Atomic Research Centre, Mumbai 85 (India); Nataliya, B. [Lebedev Physical Institute, Moscow (Russian Federation)

    2010-12-01T23:59:59.000Z

    Experimental investigations conducted on low density structured materials, such as foams have been presented in this paper. These low density foam targets having a density greater than the critical density of the laser produced plasma ({rho}{sub cr{approx_equal}}3 mg{center_dot}cm{sup -3} at laser wavelength 1.06 {mu}m) have been envisaged to have enhanced laser absorption. Experiments were done with an indigenously developed, focused 15 Joule/500 ps Nd: Glass laser at {lambda} = 1064 nm. The focused laser intensity on the target was in the range of I{approx_equal}10{sup 13}-2x10{sup 14} W/cm{sup 2}. Laser absorption was determined by energy balance experiments. Laser energy absorption was observed to be higher than 85%. In another set of experiments, low density carbon foam targets of density 150 mg/cc were compared with the solid carbon targets. The x-ray emission in the soft x-ray region was observed to increase in foam target by about 1.8 times and 2.3 times in carbon foam and Pt doped foam as compared to solid carbon. Further, investigations were also carried out to measure the energy transmitted through the sub-critical density TAC foam targets having a density less than 3 mg/cc. Such targets have been proposed to be used for smoothening of intensity ripples in a high power laser beam profile. Transmission exceeding 1.87% has been observed and consistent with results from other laboratories.

  13. Two photon absorption laser induced fluorescence measurements of neutral density in a helicon plasma

    SciTech Connect (OSTI)

    Galante, M. E.; Magee, R. M.; Scime, E. E. [Department of Physics, West Virginia University, Morgantown, West Virginia 26506 (United States)] [Department of Physics, West Virginia University, Morgantown, West Virginia 26506 (United States)

    2014-05-15T23:59:59.000Z

    We have developed a new diagnostic based on two-photon absorption laser induced fluorescence (TALIF). We use a high intensity (5?MW/cm{sup 2}), narrow bandwidth (0.1?cm{sup ?1}) laser to probe the ground state of neutral hydrogen, deuterium and krypton with spatial resolution better than 0.2?cm, a time resolution of 10?ns, and a measurement cadence of 20?Hz. Here, we describe proof-of-principle measurements in a helicon plasma source that demonstrate the TALIF diagnostic is capable of measuring neutral densities spanning four orders of magnitude; comparable to the edge neutral gradients predicted in the DIII-D tokamak pedestal. The measurements are performed in hydrogen and deuterium plasmas and absolute calibration is accomplished through TALIF measurements in neutral krypton. The optical configuration employed is confocal, i.e., both light injection and collection are accomplished with a single lens through a single optical port in the vacuum vessel. The wavelength resolution of the diagnostic is sufficient to separate hydrogen and deuterium spectra and we present measurements from mixed hydrogen and deuterium plasmas that demonstrate isotopic abundance measurements are feasible. Time resolved measurements also allow us to explore the evolution of the neutral hydrogen density and temperature and effects of wall recycling. We find that the atomic neutral density grows rapidly at the initiation of the discharge, reaching the steady-state value within 1?ms. Additionally, we find that neutral hydrogen atoms are born with 0.08?eV temperatures, not 2?eV as is typically assumed.

  14. Laboratories to Explore the Frontiers of Plasma Science VLBACHANDRA

    E-Print Network [OSTI]

    . · NRC Interim Report identified "integrated physics of a self-heated plasma" as one of the critical plasma and self-heating issues

  15. arc plasma science: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    critical ionization velocity. However, due to their pulsed nature, throughput such an electrodeless plasma centrifuge. First we will summarize advantages of the plasma...

  16. IOP PUBLISHING PLASMA SOURCES SCIENCE AND TECHNOLOGY Plasma Sources Sci. Technol. 16 (2007) 832838 doi:10.1088/0963-0252/16/4/019

    E-Print Network [OSTI]

    2007-01-01T23:59:59.000Z

    IOP PUBLISHING PLASMA SOURCES SCIENCE AND TECHNOLOGY Plasma Sources Sci. Technol. 16 (2007) 832 of droplets which are ejected from the molten metal at the wire tip by an electric pinch propelling them

  17. Effect of shockwave-induced density jump on laser plasma interactions in low-pressure ambient air

    E-Print Network [OSTI]

    Tillack, Mark

    1 Effect of shockwave-induced density jump on laser plasma interactions in low-pressure ambient air jump were investigated in low- pressure ambient air during the laser pulse using an optical interferometer. A tiny shockwave-induced density jump could be observed clearly in ambient air with pressure

  18. Comparison of surface vacuum ultraviolet emissions with resonance level number densities. I. Argon plasmas

    SciTech Connect (OSTI)

    Boffard, John B., E-mail: jboffard@wisc.edu; Lin, Chun C. [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); Culver, Cody [Materials Science Program, University of Wisconsin, Madison, WI 53706 (United States); Wang, Shicong; Wendt, Amy E. [Department of Electrical and Computer Engineering, University of Wisconsin, Madison, WI 53706 (United States); Radovanov, Svetlana; Persing, Harold [Varian Semiconductor Equipment, Applied Materials Inc., Gloucester, MA 01939 (United States)

    2014-03-15T23:59:59.000Z

    Vacuum ultraviolet (VUV) photons emitted from excited atomic states are ubiquitous in material processing plasmas. The highly energetic photons can induce surface damage by driving surface reactions, disordering surface regions, and affecting bonds in the bulk material. In argon plasmas, the VUV emissions are due to the decay of the 1s{sub 4} and 1s{sub 2} principal resonance levels with emission wavelengths of 104.8 and 106.7?nm, respectively. The authors have measured the number densities of atoms in the two resonance levels using both white light optical absorption spectroscopy and radiation-trapping induced changes in the 3p{sup 5}4p?3p{sup 5}4s branching fractions measured via visible/near-infrared optical emission spectroscopy in an argon inductively coupled plasma as a function of both pressure and power. An emission model that takes into account radiation trapping was used to calculate the VUV emission rate. The model results were compared to experimental measurements made with a National Institute of Standards and Technology-calibrated VUV photodiode. The photodiode and model results are in generally good accord and reveal a strong dependence on the neutral gas temperature.

  19. Fine density/design variable Computational Science and Engineering

    E-Print Network [OSTI]

    Paulino, Glaucio H.

    1400 1600 FE Analysis Optimization Initialization Buildings designed to minimize seismic or wind of the topology for a lower computational cost · National Science Foundation Coarse displacement mesh meshes · Topology optimization can be used to tailor cost effective structures or microstructures

  20. Diagnosing ions and neutrals via n=2 excited hydrogen atoms in plasmas with high electron density and low electron temperature

    SciTech Connect (OSTI)

    Shumack, A. E.; Schram, D. C.; Biesheuvel, J.; Goedheer, W. J.; Rooij, G. J. van [FOM-Institute for Plasma Physics Rijnhuizen, Association EURATOM-FOM, Trilateral Euregio Cluster, Nieuwegein (Netherlands)

    2011-03-15T23:59:59.000Z

    Ion and neutral parameters are determined in the high electron density, magnetized, hydrogen plasma beam of an ITER divertor relevant plasma via measurements of the n=2 excited neutrals. Ion rotation velocity (up to 7 km/s) and temperature (2-3 eV{approx}T{sub e}) are obtained from analysis of H{alpha} spectra measured close to the plasma source. The methodology for neutral density determination is explained whereby measurements in the linear plasma beam of Pilot-PSI are compared to modeling. Ground-state atomic densities are obtained via the production rate of n=2 and the optical thickness of the Lyman-{alpha} transition (escape factor {approx}0.6) and yield an ionization degree >85% and dissociation degree in the residual gas of {approx}4%. A 30% proportion of molecules with a rovibrational excitation of more than 2 eV is deduced from the production rate of n=2 atoms. This proportion increases by more than a factor of 4 for a doubling of the electron density in the transition to ITER divertor relevant electron densities, probably because of a large increase in the production and confinement of ground-state neutrals. Measurements are made using laser-induced fluorescence (LIF) and absorption, the suitability of which are evaluated as diagnostics for this plasma regime. Absorption is found to have a much better sensitivity than LIF, mainly owing to competition with background emission.

  1. Porkolab_FPA_12.4.2008 Plasma Science and Fusion Center

    E-Print Network [OSTI]

    engineers, 1 technician and 4 graduate students #12;Porkolab_FPA_12.4.2008 The LDX is located at MITPorkolab_FPA_12.4.2008 Plasma Science and Fusion Center Highlights of Some Research Activities and the C-Mod Team Compact high- performance divertor tokamak research to establish the plasma physics

  2. Low Temperature Plasma Science: Not Only the Fourth State of Matter but All of Them. Report of the Department of Energy Office of Fusion Energy Sciences Workshop on Low Temperature Plasmas, March 25-57, 2008

    SciTech Connect (OSTI)

    None

    2008-09-01T23:59:59.000Z

    Low temperature plasma science (LTPS) is a field on the verge of an intellectual revolution. Partially ionized plasmas (often referred to as gas discharges) are used for an enormous range of practical applications, from light sources and lasers to surgery and making computer chips, among many others. The commercial and technical value of low temperature plasmas (LTPs) is well established. Modern society would simply be less advanced in the absence of LTPs. Much of this benefit has resulted from empirical development. As the technology becomes more complex and addresses new fields, such as energy and biotechnology, empiricism rapidly becomes inadequate to advance the state of the art. The focus of this report is that which is less well understood about LTPs - namely, that LTPS is a field rich in intellectually exciting scientific challenges and that addressing these challenges will result in even greater societal benefit by placing the development of plasma technologies on a solid science foundation. LTPs are unique environments in many ways. Their nonequilibrium and chemically active behavior deviate strongly from fully ionized plasmas, such as those found in magnetically confined fusion or high energy density plasmas. LTPs are strongly affected by the presence of neutral species-chemistry adds enormous complexity to the plasma environment. A weakly to partially ionized gas is often characterized by strong nonequilibrium in the velocity and energy distributions of its neutral and charged constituents. In nonequilibrium LTP, electrons are generally hot (many to tens of electron volts), whereas ions and neutrals are cool to warm (room temperature to a few tenths of an electron volt). Ions and neutrals in thermal LTP can approach or exceed an electron volt in temperature. At the same time, ions may be accelerated across thin sheath boundary layers to impact surfaces, with impact energies ranging up to thousands of electron volts. These moderately energetic electrons can efficiently create reactive radical fragments and vibrationally and electronically excited species from collisions with neutral molecules. These chemically active species can produce unique structures in the gas phase and on surfaces, structures that cannot be produced in other ways, at least not in an economically meaningful way. Photons generated by electron impact excited species in the plasma can interact more or less strongly with other species in the plasma or with the plasma boundaries, or they can escape from the plasma. The presence of boundaries around the plasma creates strong gradients where plasma properties change dramatically. It is in these boundary regions where externally generated electromagnetic radiation interacts most strongly with the plasma, often producing unique responses. And it is at bounding surfaces where complex plasma-surface interactions occur. The intellectual challenges associated with LTPS center on several themes, and these are discussed in the chapters that follow this overview. These themes are plasma-surface interactions; kinetic, nonlinear properties of LTP; plasmas in multiphase media; scaling laws for LTP; and crosscutting themes: diagnostics, modeling, and fundamental data.

  3. THE SCIENCE FRONTIER OF MFE BURNING PLASMA PHYSICS

    E-Print Network [OSTI]

    plasma and self-heating issues for magnetic fusion. #12;THERE ARE TWO TYPES OF BURNING PLASMA ISSUES PHENOMENA #12;MANY NEW AND EXCITING PHENOMENA TO STUDY IN A BP NEW ELEMENTS IN A BURNING PLASMAS: SELF-HEATED-ALFVéNIC ALPHAS · HIGHLY NON-LINEAR INTERACTION OF ALPHA SELF-HEATING WITH STRONGLY COUPLED ADVANCED TOKAMAK

  4. Measurements of electron density and temperature in the H-1 heliac plasma by helium line intensity ratios

    SciTech Connect (OSTI)

    Ma Shuiliang; Howard, John; Blackwell, Boyd D.; Thapar, Nandika [Plasma Research Laboratory, Australian National University, Canberra ACT 0200 (Australia)

    2012-03-15T23:59:59.000Z

    Electron density and temperature distributions in the H-1 heliac plasma are measured using the helium line intensity ratio technique based on a collisional-radiative model. An inversion approach with minimum Fisher regularization is developed to reconstruct the ratios of the local emission radiances from detected line-integrated intensities. The electron density and temperature inferred from the He I 667.8/728.1 and He I 728.1/706.5 nm line ratios are in good agreement with those from other diagnostic techniques in the inner region of the plasma. The electron density and temperature values appear to be a little high in the outer region of the plasma. Some possible causes of the discrepancy in the outer region are discussed.

  5. CH spectroscopy for carbon chemical erosion analysis in high density low temperature hydrogen plasma

    SciTech Connect (OSTI)

    Westerhout, J.; Rooij, G. J. van [FOM Institute for Plasma Physics Rijnhuizen, Association EURATOM-FOM, Trilateral Euregio Cluster, P. O. Box 1207, 3430 BE Nieuwegein (Netherlands); Lopes Cardozo, N. J. [FOM Institute for Plasma Physics Rijnhuizen, Association EURATOM-FOM, Trilateral Euregio Cluster, P. O. Box 1207, 3430 BE Nieuwegein (Netherlands); Eindhoven University of Technology, P. O. Box 513, 5600 MB Eindhoven (Netherlands); Rapp, J. [FOM Institute for Plasma Physics Rijnhuizen, Association EURATOM-FOM, Trilateral Euregio Cluster, P. O. Box 1207, 3430 BE Nieuwegein (Netherlands); Institut fuer Energieforschung--Plasmaphysik, Forschungszentrum Juelich, Association EURATOM-FZJ, Trilateral Euregio Cluster, D-52425 Juelich (Germany)

    2009-10-12T23:59:59.000Z

    The CH A-X molecular band is measured upon seeding the hydrogen plasma in the linear plasma generator Pilot-PSI [electron temperature T{sub e}=0.1-2.5 eV and electron density n{sub e}=(0.5-5)x10{sup 20} m{sup -3}] with methane. Calculated inverse photon efficiencies for these conditions range from 3 up to >10{sup 6} due to a steeply decreasing electron excitation cross section. The experiments contradict the calculations and show a constant effective inverse photon efficiency of {approx}100 for T{sub e}<1 eV. The discrepancy is explained as the CH A level is populated through dissociative recombination of the molecular ions formed by charge exchange. Collisional de-excitation is observed for n{sub e}>5x10{sup 20} m{sup -3} and 0.1 eV

  6. Wavefront-sensor-based electron density measurements for laser-plasma accelerators

    E-Print Network [OSTI]

    Plateau, Guillaume

    2010-01-01T23:59:59.000Z

    After imaging the plasma to a primary focus shortly afterfocus was 1 mm above the nozzle. The laser pulse excited a plasma

  7. Sean Finnegan & Ann Satsangi Fusion Energy Sciences

    E-Print Network [OSTI]

    Energy (IFE) science. #12;HEDLP definition "High-energy-density laboratory plasma (HEDLP) physicsSean Finnegan & Ann Satsangi Fusion Energy Sciences Program Management Team for HEDLP Fusion Power Associates15 December 2011 Comments on the DOE-SC Program in High Energy Density Laboratory Plasma Science

  8. Measurements of neutral density profiles using a deuterium Balmer-alpha diagnostic in the C-2 FRC plasma

    SciTech Connect (OSTI)

    Gupta, Deepak K.; Deng, B. H.; Knapp, K.; Sun, X.; Thompson, M. C. [Tri Alpha Energy, Rancho Santa Margarita, California 92688 (United States)

    2012-10-15T23:59:59.000Z

    In C-2 field-reversed configuration (FRC) device, low neutral density outside the FRC separatrix is required to minimize the charge exchange loss of fast particles. Titanium gettering is used in C-2 to reduce the wall recycling and keep the neutral density low in plasma edge. The measurements of neutral density radial profile are desirable to understand the plasma recycling and the effects of titanium gettering. These measurements are also needed to study the interaction of neutral beams with FRC plasma and confinement of fast ions. Diagnostic based on absolute deuterium Balmer-alpha (D-alpha) radiation measurements is developed and deployed on C-2 device to measure the radial profile of neutral density. Simultaneous measurements of electron density and temperature are done using CO{sub 2} interferometer, Thomson scattering, and triple probes diagnostics along with absolute D-alpha radiation. Abel inversion was performed to get the time dependent radial profile of the local D-alpha emission density. Neutral density profiles are obtained under different machine conditions of titanium deposition.

  9. A passive measurement of dissociated atom densities in atmospheric pressure air discharge plasmas using vacuum ultraviolet self-absorption spectroscopy

    SciTech Connect (OSTI)

    Laity, George [Center for Pulsed Power and Power Electronics, Department of Electrical and Computer Engineering and Department of Physics, Texas Tech University, Lubbock, Texas 79409 (United States); Applied Science and Technology Maturation Department, Sandia National Laboratories, Albuquerque, New Mexico 87123 (United States); Fierro, Andrew; Dickens, James; Neuber, Andreas [Center for Pulsed Power and Power Electronics, Department of Electrical and Computer Engineering and Department of Physics, Texas Tech University, Lubbock, Texas 79409 (United States); Frank, Klaus [Erlangen Centre for Astroparticle Physics, Department of Physics, Friedrich–Alexander University at Erlangen-Nürnberg, 91058 Erlangen (Germany)

    2014-03-28T23:59:59.000Z

    We demonstrate a method for determining the dissociation degree of atmospheric pressure air discharges by measuring the self-absorption characteristics of vacuum ultraviolet radiation from O and N atoms in the plasma. The atom densities are determined by modeling the amount of radiation trapping present in the discharge, without the use of typical optical absorption diagnostic techniques which require external sources of probing radiation into the experiment. For an 8.0?mm spark discharge between needle electrodes at atmospheric pressure, typical peak O atom densities of 8.5?×?10{sup 17}?cm{sup ?3} and peak N atom densities of 9.9?×?10{sup 17}?cm{sup ?3} are observed within the first ?1.0?mm of plasma near the anode tip by analyzing the OI and NI transitions in the 130.0–132.0?nm band of the vacuum ultraviolet spectrum.

  10. 2110 IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 37, NO. 11, NOVEMBER 2009 Low-Pressure Helicon-Plasma Discharge Initiation

    E-Print Network [OSTI]

    Scharer, John E.

    -temperature plasma research. Low- pressure (as low as 1 millitorr) inductively coupled plasmas are used for plasma

  11. Viscosity and dilepton production of a chemically equilibrating quark-gluon plasma at finite baryon density

    E-Print Network [OSTI]

    N. N. Guan; Z. J. He; J. L. Long; X. Z. Cai; Y. G. Ma; J. W. Li; W. Q. Shen

    2009-09-02T23:59:59.000Z

    By considering the effect of shear viscosity we have investigated the evolution of a chemically equilibrating quark-gluon plasma at finite baryon density. Based on the evolution of the system we have performed a complete calculation for the dilepton production from the following processes: $q\\bar{q}{\\to}l\\bar{l}$, $q\\bar{q}{\\to}gl\\bar{l}$, Compton-like scattering ($qg{\\to}ql\\bar{l}$, $\\bar{q}g{\\to}{\\bar{q}}l\\bar{l}$), gluon fusion $g\\bar{g}{\\to}c\\bar{c}$, annihilation $q\\bar{q}{\\to}c\\bar{c}$ as well as the multiple scattering of quarks. We have found that quark-antiquark annihilation, Compton-like scatterring, gluon fusion, and multiple scattering of quarks give important contributions. Moreover, we have also found that the dilepton yield is an increasing function of the initial quark chemical potential, and the increase of the quark phase lifetime because of the viscosity also obviously raises the dilepton yield.

  12. Increase in the energy density of the pinch plasma in 3D implosion of quasi-spherical wire arrays

    SciTech Connect (OSTI)

    Aleksandrov, V. V., E-mail: alexvv@triniti.ru [Troitsk Institute for Innovation and Fusion Research (Russian Federation); Gasilov, V. A. [Russian Academy of Sciences, Keldysh Institute of Applied Mathematics (Russian Federation); Grabovski, E. V.; Gritsuk, A. N., E-mail: griar@triniti.ru; Laukhin, Ya. N.; Mitrofanov, K. N.; Oleinik, G. M. [Troitsk Institute for Innovation and Fusion Research (Russian Federation); Ol’khovskaya, O. G. [Russian Academy of Sciences, Keldysh Institute of Applied Mathematics (Russian Federation); Sasorov, P. V.; Smirnov, V. P.; Frolov, I. N. [Troitsk Institute for Innovation and Fusion Research (Russian Federation); Shevel’ko, A. P. [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation)

    2014-12-15T23:59:59.000Z

    Results are presented from experimental studies of the characteristics of the soft X-ray (SXR) source formed in the implosion of quasi-spherical arrays made of tungsten wires and metalized kapron fibers. The experiments were carried out at the Angara-5-1 facility at currents of up to 3 MA. Analysis of the spatial distribution of hard X-ray emission with photon energies above 20 keV in the pinch images taken during the implosion of quasi-spherical tungsten wire arrays (QTWAs) showed that a compact quasi-spherical plasma object symmetric with respect to the array axis formed in the central region of the array. Using a diffraction grazing incidence spectrograph, spectra of SXR emission with wavelengths of 20–400 Å from the central, axial, and peripheral regions of the emission source were measured with spatial resolutions along the array radius and height in the implosion of QTWAs. It is shown that the emission spectra of the SXR sources formed under the implosion of quasi-spherical and cylindrical tungsten wire arrays at currents of up to 3 MA have a maximum in the wavelength range of 50–150 Å. It is found that, during the implosion of a QTWA with a profiled linear mass, a redistribution of energy in the emission spectrum takes place, which indicates that, during 3D implosion, the energy of longitudinal motion of the array material additionally contributes to the radiation energy. It is also found that, at close masses of the arrays and close values of the current in the range of 2.4{sup ?3} MA, the average energy density in the emission source formed during the implosion of a quasi-spherical wire array is larger by a factor of 7 than in the source formed during the implosion of a cylindrical wire array. The experimental data were compared with results of 3D simulations of plasma dynamics and radiation generation during the implosion of quasi-spherical wire arrays with a profiled mass by using the MARPLE-3D radiative magnetohydrodynamic code, developed at the Keldysh Institute of Applied Mathematics, Russian Academy of Sciences.

  13. Exploring Plasma Science Advances from Fusion Findings to Astrophysica...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    December 4, 2012 Tweet Widget Google Plus One Share on Facebook The latest advances in plasma physics were the focus of more than 1,000 scientists from around the world who...

  14. CO{sub 2} laser-based dispersion interferometer utilizing orientation-patterned gallium arsenide for plasma density measurements

    SciTech Connect (OSTI)

    Bamford, D. J.; Cummings, E. A.; Panasenko, D. [Physical Sciences Inc., 6652 Owens Drive, Pleasanton, California 94588 (United States)] [Physical Sciences Inc., 6652 Owens Drive, Pleasanton, California 94588 (United States); Fenner, D. B.; Hensley, J. M. [Physical Sciences Inc., 20 New England Business Center, Andover, Massachusetts 01810 (United States)] [Physical Sciences Inc., 20 New England Business Center, Andover, Massachusetts 01810 (United States); Boivin, R. L.; Carlstrom, T. N.; Van Zeeland, M. A. [General Atomics, P.O. Box 85608, San Diego, California 92186 (United States)] [General Atomics, P.O. Box 85608, San Diego, California 92186 (United States)

    2013-09-15T23:59:59.000Z

    A dispersion interferometer based on the second-harmonic generation of a carbon dioxide laser in orientation-patterned gallium arsenide has been developed for measuring electron density in plasmas. The interferometer includes two nonlinear optical crystals placed on opposite sides of the plasma. This instrument has been used to measure electron line densities in a pulsed radio-frequency generated argon plasma. A simple phase-extraction technique based on combining measurements from two successive pulses of the plasma has been used. The noise-equivalent line density was measured to be 1.7 × 10{sup 17} m{sup ?2} in a detection bandwidth of 950 kHz. One of the orientation-patterned crystals produced 13 mW of peak power at the second-harmonic wavelength from a carbon dioxide laser with 13 W of peak power. Two crystals arranged sequentially produced 58 mW of peak power at the second-harmonic wavelength from a carbon dioxide laser with 37 W of peak power.

  15. Wall current probe: A non-invasive in situ plasma diagnostic for space and time resolved current density distribution measurement

    SciTech Connect (OSTI)

    Baude, R.; Gaboriau, F.; Hagelaar, G. J. M. [Université de Toulouse, UPS, INPT, LAPLACE (Laboratoire Plasma et Conversion d’énergie), 118 route de Narbonne, F-31062 Toulouse Cedex 9, France and CNRS, LAPLACE, F-31062, Toulouse (France)] [Université de Toulouse, UPS, INPT, LAPLACE (Laboratoire Plasma et Conversion d’énergie), 118 route de Narbonne, F-31062 Toulouse Cedex 9, France and CNRS, LAPLACE, F-31062, Toulouse (France)

    2013-08-15T23:59:59.000Z

    In the context of low temperature plasma research, we propose a wall current probe to determine the local charged particle fluxes flowing to the chamber walls. This non-intrusive planar probe consists of an array of electrode elements which can be individually biased and for which the current can be measured separately. We detail the probe properties and present the ability of the diagnostic to be used as a space and time resolved measurement of the ion and electron current density at the chamber walls. This diagnostic will be relevant to study the electron transport in magnetized low-pressure plasmas.

  16. Heavy Ion Fusion Science Virtual National Laboratory 1st Quarter FY08 Milestone Report: Report Initial Work on Developing Plasma Modeling Capability in WARP for NDCX Experiments Report Initial work on developing Plasma Modeling Capability in WARP for NDCX Experiments

    E-Print Network [OSTI]

    Friedman, A.

    2008-01-01T23:59:59.000Z

    plasma and (b) just past the time of peak compression and focus.plasma simulation models in Warp is to enable simulations of neutralized longitudinal compression and focuscm -3 at focus. The base case examined has a plasma density

  17. Helicon plasma generator-assisted surface conversion ion source for the production of H{sup -} ion beams at the Los Alamos Neutron Science Center

    SciTech Connect (OSTI)

    Tarvainen, O.; Rouleau, G.; Keller, R.; Geros, E.; Stelzer, J.; Ferris, J. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    2008-02-15T23:59:59.000Z

    The converter-type negative ion source currently employed at the Los Alamos Neutron Science Center (LANSCE) is based on cesium enhanced surface production of H{sup -} ion beams in a filament-driven discharge. In this kind of an ion source the extracted H{sup -} beam current is limited by the achievable plasma density which depends primarily on the electron emission current from the filaments. The emission current can be increased by increasing the filament temperature but, unfortunately, this leads not only to shorter filament lifetime but also to an increase in metal evaporation from the filament, which deposits on the H{sup -} converter surface and degrades its performance. Therefore, we have started an ion source development project focused on replacing these thermionic cathodes (filaments) of the converter source by a helicon plasma generator capable of producing high-density hydrogen plasmas with low electron energy. In our studies which have so far shown that the plasma density of the surface conversion source can be increased significantly by exciting a helicon wave in the plasma, and we expect to improve the performance of the surface converter H{sup -} ion source in terms of beam brightness and time between services. The design of this new source and preliminary results are presented, along with a discussion of physical processes relevant for H{sup -} ion beam production with this novel design. Ultimately, we perceive this approach as an interim step towards our long-term goal, combining a helicon plasma generator with an SNS-type main discharge chamber, which will allow us to individually optimize the plasma properties of the plasma cathode (helicon) and H{sup -} production (main discharge) in order to further improve the brightness of extracted H{sup -} ion beams.

  18. Surface Science Letters Surface vibrations of a highly ordered low-density alkanethiol

    E-Print Network [OSTI]

    Sibener, Steven

    ; Surface structure, morphology, roughness, and topography; Vibrations of adsorbed molecules; Gold; LowSurface Science Letters Surface vibrations of a highly ordered low-density alkanethiol monolayer-energy surface vibrational structure of the 11:5 Â p 3 striped phase of 1-decanethiol (C10H21SH) chemi- sorbed

  19. Materials Science and Engineering A 445446 (2007) 186192 Plastic instabilities and dislocation densities during plastic

    E-Print Network [OSTI]

    Gubicza, Jenõ

    2007-01-01T23:59:59.000Z

    Materials Science and Engineering A 445­446 (2007) 186­192 Plastic instabilities and dislocation densities during plastic deformation in Al­Mg alloys Gyozo Horv´ath, Nguyen Q. Chinh, Jeno Gubicza, J 2006 Abstract Plastic deformation of Al­Mg alloys were investigated by analyzing the stress

  20. 92 IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 30, NO. 1, FEBRUARY 2002 Formation of Coulomb Crystals in a

    E-Print Network [OSTI]

    Kushner, Mark

    sheaths. DUST PARTICLE transport in partially ionized plasmas has been the focus of many recent92 IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 30, NO. 1, FEBRUARY 2002 Formation of Coulomb Crystals in a Capacitively Coupled Plasma Vivek Vyas and Mark J. Kushner, Fellow, IEEE Abstract--Dust particle transport

  1. 1738 IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 36, NO. 4, AUGUST 2008 Propagation of a Short Intense Laser Pulse

    E-Print Network [OSTI]

    Strathclyde, University of

    , the propagation of a short intense laser pulse in a curved plasma channel is considered. The effects of the shape1738 IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 36, NO. 4, AUGUST 2008 Propagation of a Short Intense Laser Pulse in a Curved Plasma Channel Albert Reitsma and Dino Jaroszynski Abstract--In this paper

  2. High repetition rate plasma mirror device for attosecond science

    SciTech Connect (OSTI)

    Borot, A.; Douillet, D.; Iaquaniello, G.; Lefrou, T.; Lopez-Martens, R. [Laboratoire d'Optique Appliquée, ENSTA-ParisTech, CNRS, Ecole Polytechnique, UMR 7639, 91761 Palaiseau (France)] [Laboratoire d'Optique Appliquée, ENSTA-ParisTech, CNRS, Ecole Polytechnique, UMR 7639, 91761 Palaiseau (France); Audebert, P.; Geindre, J.-P. [Laboratoire pour l'Utilisation des Lasers Intenses, Ecole Polytechnique, CNRS, 91128 Palaiseau Cedex (France)] [Laboratoire pour l'Utilisation des Lasers Intenses, Ecole Polytechnique, CNRS, 91128 Palaiseau Cedex (France)

    2014-01-15T23:59:59.000Z

    This report describes an active solid target positioning device for driving plasma mirrors with high repetition rate ultra-high intensity lasers. The position of the solid target surface with respect to the laser focus is optically monitored and mechanically controlled on the nm scale to ensure reproducible interaction conditions for each shot at arbitrary repetition rate. We demonstrate the target capabilities by driving high-order harmonic generation from plasma mirrors produced on glass targets with a near-relativistic intensity few-cycle pulse laser system operating at 1 kHz. During experiments, residual target surface motion can be actively stabilized down to 47?nm (root mean square), which ensures sub-300-as relative temporal stability of the plasma mirror as a secondary source of coherent attosecond extreme ultraviolet radiation in pump-probe experiments.

  3. Observation of a new high-? and high-density state of a magnetospheric plasma in RT-1

    SciTech Connect (OSTI)

    Saitoh, H.; Yano, Y.; Yoshida, Z.; Nishiura, M.; Morikawa, J.; Kawazura, Y.; Nogami, T.; Yamasaki, M. [Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561 (Japan)

    2014-08-15T23:59:59.000Z

    A new high-? and high-density state is reported for a plasma confined in a laboratory magnetosphere. In order to expand the parameter regime of an electron cyclotron resonance heating experiment, the 8.2?GHz microwave power of the Ring Trap 1 device has been upgraded with the installation of a new waveguide system. The rated input power launched from a klystron was increased from 25 to 50?kW, which enabled the more stable formation of a hot-electron high-? plasma. The diamagnetic signal (the averaged value of four magnetic loops signals) of a plasma reached 5.2 mWb. According to a two-dimensional Grad-Shafranov analysis, the corresponding local ? value is close to 100%.

  4. Increasing the upper-limit intensity and temperature range for thermal self-focusing of a laser beam by using plasma density ramp-up

    SciTech Connect (OSTI)

    Bokaei, B.; Niknam, A. R., E-mail: a-niknam@sbu.ac.ir [Laser and Plasma Research Institute, Shahid Beheshti University, G.C., Tehran (Iran, Islamic Republic of)

    2014-03-15T23:59:59.000Z

    This work is devoted to improving relativistic and ponderomotive thermal self-focusing of the intense laser beam in an underdense plasma. It is shown that the ponderomotive nonlinearity induces a saturation mechanism for thermal self-focusing. Therefore, in addition to the well-known lower-limit critical intensity, there is an upper-limit intensity for thermal self-focusing above which the laser beam starts to experience ponderomotive defocusing. It is indicated that the upper-limit intensity value is dependent on plasma and laser parameters such as the plasma electron temperature, plasma density, and laser spot size. Furthermore, the effect of the upward plasma density ramp profile on the thermal self-focusing is studied. Results show that by using the plasma density ramp-up, the upper-limit intensity increases and the self-focusing temperature range expands.

  5. Multichannel microwave interferometer with an antenna switching system for electron density measurement in a laboratory plasma experiment

    SciTech Connect (OSTI)

    Kawamori, Eiichirou; Lin, Yu-Hsiang [Institute of Space and Plasma Sciences, National Cheng Kung University, Tainan 70101, Taiwan (China)] [Institute of Space and Plasma Sciences, National Cheng Kung University, Tainan 70101, Taiwan (China); Mase, Atsushi [Art, Science and Technology Center for Cooperative Research, Kyushu University, Kasuga 816-8580 (Japan)] [Art, Science and Technology Center for Cooperative Research, Kyushu University, Kasuga 816-8580 (Japan); Nishida, Yasushi; Cheng, C. Z. [Institute of Space and Plasma Sciences, National Cheng Kung University, Tainan 70101, Taiwan (China) [Institute of Space and Plasma Sciences, National Cheng Kung University, Tainan 70101, Taiwan (China); Plasma and Space Science Center, National Cheng Kung University, Tainan 70101, Taiwan (China)

    2014-02-15T23:59:59.000Z

    This study presents a simple and powerful technique for multichannel measurements of the density profile in laboratory plasmas by microwave interferometry. This technique uses electromechanical microwave switches to temporally switch the connection between multiple receiver antennas and one phase-detection circuit. Using this method, the phase information detected at different positions is rearranged into a time series that can be acquired from a minimum number of data acquisition channels (e.g., two channels in the case of quadrature detection). Our successfully developed multichannel microwave interferometer that uses the antenna switching method was applied to measure the radial electron density profiles in a magnetized plasma experiment. The advantage of the proposed method is its compactness and scalability to multidimensional measurement systems at low cost.

  6. Determination of the respective density distributions of low-and high-density lipoprotein particles in bovine plasma

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    .006-1.210 g/ml were separated by density gradient ultracentrifugation into 25 fractions. Their respective apo-I and apo B. Gradient distributions of apo A-I (d 1.046-1.180 g/ml; max at d 1.080 g/ml) and apo B (d 1: Intestinal Lipid and Lipoprotein Metabolism (Windler E, Greten H, eds), W Zuckschwerdt Verlag, Munchen, 50

  7. Temperature and density evolution during decay in a 2.45 GHz hydrogen electron cyclotron resonance plasma: Off-resonant and resonant cases

    SciTech Connect (OSTI)

    Cortázar, O. D. [ESS Bilbao, Edificio Cosimet, Landabarri 2, 48940-Leioa, Vizcaya (Spain) [ESS Bilbao, Edificio Cosimet, Landabarri 2, 48940-Leioa, Vizcaya (Spain); Universidad de Castilla-La Mancha, ETSII, C.J. Cela s/n, 13170 Ciudad Real (Spain); Megía-Macías, A.; Vizcaíno-de-Julián, A. [ESS Bilbao, Edificio Cosimet, Landabarri 2, 48940-Leioa, Vizcaya (Spain)] [ESS Bilbao, Edificio Cosimet, Landabarri 2, 48940-Leioa, Vizcaya (Spain)

    2013-09-15T23:59:59.000Z

    Time resolved electron temperature and density measurements during the decay stage in a hydrogen electron cyclotron resonance (ECR) plasma are presented for a resonance and off-resonance magnetic field configurations. The measurements are conducted on a ECR plasma generator excited at 2.45 GHz denominated test-bench for ion-sources plasma studies at ESS Bilbao. The plasma parameters evolution is studied by Langmuir probe diagnostic with synchronized sample technique developed for repetitive pulsed plasmas with a temporal resolution of 200 ns in typical decay processes of about 40 ?s. An afterglow transient is clearly observed in the reflected microwave power signal from the plasma. Simultaneously, the electron temperature evolution shows rebounding peaks that may be related to the interplay between density drop and microwave coupling with deep impact on the Electron Energy Distribution Function. The correlation of such structures with the plasma absorbed power and the coupling quality is also reported.

  8. Numerical solutions of sheath structures in front of an electron-emitting electrode immersed in a low-density plasma

    SciTech Connect (OSTI)

    Din, Alif [Theoretical Plasma Physics Division, PINSTECH, P. O. Nilore, 44000 Islamabad (Pakistan)] [Theoretical Plasma Physics Division, PINSTECH, P. O. Nilore, 44000 Islamabad (Pakistan)

    2013-09-15T23:59:59.000Z

    The exact theoretical expressions involved in the formation of sheath in front of an electron emitting electrode immersed in a low-density plasma have been derived. The potential profile in the sheath region has been calculated for subcritical, critical, and supercritical emissions. The potential profiles of critical and supercritical emissions reveals that we must take into account a small, instead of zero, electric field at the sheath edge to satisfy the boundary conditions used to integrate the Poisson's equation. The I-V curves for critical emission shows that only high values of plasma-electron to emitted-electron temperature ratio can meet the floating potential of the emissive electrode. A one-dimensional fluid like model is assumed for ions, while the electron species are treated as kinetic. The distribution of emitted-electron from the electrode is assumed to be half Maxwellian. The plasma-electron enters the sheath region at sheath edge with half Maxwellian velocity distribution, while the reflected ones have cut-off velocity distribution due to the absorption of super thermal electrons by the electrode. The effect of varying emitted-electron current on the sheath structure has been studied with the help of a parameter G (the ratio of emitted-electron to plasma-electron densities)

  9. Convective Cell Formation in a Z-Pinch Plasma Science and Fusion Center

    E-Print Network [OSTI]

    Convective Cell Formation in a Z-Pinch J. Kesner Plasma Science and Fusion Center Massachusetts Institute of Technology Cambridge, MA 02139 PSFC Report PSFC/JA-02-27 Abstract Closed field line confinement given by Eq. (1). These equations were then applied to a hard core z pinch which can be considered

  10. Study of density fluctuations and particle transport at the edge of I-mode plasmas

    E-Print Network [OSTI]

    Dominguez, Arturo, Ph. D. Massachusetts Institute of Technology

    2012-01-01T23:59:59.000Z

    The wide range of plasma parameters available on Alcator C-Mod has led to the accessibility of many regimes of operation. Since its commissioning, C-Mod has accessed the Linear ohmic confinement, Saturated ohmic confinement, ...

  11. Science On Saturday Archive | Princeton Plasma Physics Lab

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOnItemResearch > TheNuclearHomeland Science Stockpile2015HighlightsScience Upcoming

  12. Worldwide conference on plasma science coming to Princeton area | Princeton

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over OurThe Iron SpinPrincetonUsingWhat isJoin theanniversary lectureLosPlasma

  13. COLLOQUIUM: The Promise of Urban Science | Princeton Plasma Physics Lab

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625govInstrumentstdmadapInactiveVisiting the TWPSuccess StoriesFebruary 26, 2014, 4:00pmPlasma Physics19,AprilApril

  14. Nanoparticle manipulation in the near-substrate areas of low-temperature, high-density rf plasmas

    SciTech Connect (OSTI)

    Rutkevych, P.P.; Ostrikov, K.; Xu, S. [Plasma Sources and Applications Center, National Institute of Education (NIE), Nanyang Technological University, 1 Nanyang Walk, Singapore 637616 (Singapore); School of Physics, The University of Sydney, Sydney, New South Wales 2006 (Australia); Plasma Sources and Applications Center, National Institute of Education (NIE), Nanyang Technological University, 1 Nanyang Walk, Singapore 637616 (Singapore)

    2005-10-01T23:59:59.000Z

    Manipulation of a single nanoparticle in the near-substrate areas of high-density plasmas of low-temperature glow discharges is studied. It is shown that the nanoparticles can be efficiently manipulated by the thermophoretic force controlled by external heating of the substrate stage. Particle deposition onto or repulsion from nanostructured carbon surfaces critically depends on the values of the neutral gas temperature gradient in the near-substrate areas, which is directly measured in situ in different heating regimes by originally developed temperature gradient probe. The measured values of the near-surface temperature gradient are used in the numerical model of nanoparticle dynamics in a variable-length presheath. Specific conditions enabling the nanoparticle to overcome the repulsive potential and deposit on the substrate during the discharge operation are investigated. The results are relevant to fabrication of various nanostructured films employing structural incorporation of the plasma-grown nanoparticles, in particular, to nanoparticle deposition in the plasma-enhanced chemical-vapor deposition of carbon nanostructures in hydrocarbon-based plasmas.

  15. Multi-dimensional collective effects in high-current relativistic beams relevant to High Density Laboratory Plasmas

    SciTech Connect (OSTI)

    Shvets, Gennady

    2014-05-09T23:59:59.000Z

    In summary, an analytical model describing the self-pinching of a relativistic charge-neutralized electron beam undergoing the collisionless Weibel instability in an overdense plasma has been developed. The model accurately predicts the final temperature and size of the self-focused filament. It is found that the final temperature is primarily defined by the total beam’s current, while the filament’s radius is shown to be smaller than the collisionless skin depth in the plasma and primarily determined by the beam’s initial size. The model also accurately predicts the repartitioning ratio of the initial energy of the beam’s forward motion into the magnetic field energy and the kinetic energy of the surrounding plasma. The density profile of the final filament is shown to be a superposition of the standard Bennett pinch profile and a wide halo surrounding the pinch, which contains a significant fraction of the beam’s electrons. PIC simulations confirm the key assumption of the analytic theory: the collisionless merger of multiple current filaments in the course of the Weibel Instability provides the mechanism for Maxwellization of the beam’s distribution function. Deviations from the Maxwell-Boltzmann distribution are explained by incomplete thermalization of the deeply trapped and halo electrons. It is conjectured that the simple expression derived here can be used for understanding collsionless shock acceleration and magnetic field amplification in astrophysical plasmas.

  16. PLASMA PHYSICS:Turbulence and Sheared Flow --Burrell 281 (5384): 1816 --Science q My Science

    E-Print Network [OSTI]

    Lin, Zhihong

    the loss of energy from the plasma. One of the success stories of magnetic fusion research over the past. Burrell* In the quest for fusion energy, a continuing theme is the search for ways to improve energy. When present, these global MHD instabilities can typically tear apart in microseconds a plasma whose

  17. Science on Saturday starts Jan. 11 | Princeton Plasma Physics Lab

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    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's PossibleRadiationImplementingnpitcheResearch BriefsTenney,Science and

  18. Plasma density over Svalbard during the ISBJRN campaign C. M. Hall1

    E-Print Network [OSTI]

    Boyer, Edmond

    and below measurements have been impeded by ``clutter'' or interference (the exact cause being unclear previously from Andùya Rocket Range on the Norwegian mainland, this presented an unprecedented in situ determination of positive ion density over Svalbard. Simultaneously, ESR measured similar density pro

  19. Influence of ambient gas on the temperature and density of laser produced carbon plasma

    E-Print Network [OSTI]

    Harilal, S. S.

    ; accepted for publication 11 November 1997 The effect of ambient gas on the dynamics of the plasma generated In moderate or high pressures, a blast wave model is found to describe accurately the plume propagation the maximum plume length with considerable accuracy.7,13 In this letter we report the effect of ambient

  20. NJ Regional Middle School Science Bowl | Princeton Plasma Physics Lab

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    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC)Integrated Codes |IsLoveReferenceAgenda Workshop AgendaGraphicNIF & PhotonAwards2,

  1. New Jersey Regional Science Bowl | Princeton Plasma Physics Lab

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  2. Science Education Upcoming Events | Princeton Plasma Physics Lab

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  3. MIT Plasma Science & Fusion Center: research, alcator, pubs,

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  4. MIT Plasma Science & Fusion Center: research, alcator, pubs,

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  5. MIT Plasma Science & Fusion Center: research, alcator, research program

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  6. MIT's Plasma Science Fusion Center: Tokamak Experiments Come Clean about

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC)Integrated Codes |IsLove Your Home and It'll Love YouTokamak | Princeton

  7. Propagation of a cloud of hot electrons through a plasma in the presence of Langmuir scattering by ambient density fluctuations

    SciTech Connect (OSTI)

    Foroutan, G. R.; Robinson, P. A.; Sobhanian, S.; Moslehi-Fard, M.; Li, B.; Cairns, I. H. [School of Physics, University of Sydney, NSW 2006, Sydney (Australia); Research Institute for Astronomy and Astrophysics of Maragha, P.O. Box 55134-441 Maragha (Iran, Islamic Republic of) and Physics Department, Faculty of Science, Sahand University of Technology, 51335-1996 Tabriz (Iran); School of Physics, University of Sydney, NSW 2006, Sydney (Australia); Research Institute for Astronomy and Astrophysics of Maragha, P.O. Box 55134-441 Maragha (Iran, Islamic Republic of) and Faculty of Physics, Tabriz University, Tabriz 51664 (Iran); Faculty of Physics, Tabriz University, Tabriz 51664 (Iran, Islamic Republic of); School of Physics, University of Sydney, NSW 2006, Sydney (Australia)

    2007-01-15T23:59:59.000Z

    Gas-dynamic theory is generalized to incorporate the effects of beam-driven Langmuir waves scattering off ambient density fluctuations, and the consequent effects on the propagation of a cloud of hot electrons in an inhomogeneous plasma. Assuming Langmuir scattering as the limit of nonlinear three-wave interactions with fluctuations that are weak, low-frequency, long-wavelength ion-sound waves, the net effect of scattering is equivalent to effective damping of the Langmuir waves. Under the assumption of self-similarity in the evolution of the beam and Langmuir wave distribution functions, gas-dynamic theory shows that the effects of Langmuir scattering on the beam distribution are equivalent to a perturbation in the injection profile of the beam. Analytical expressions are obtained for the height of the plateau of the beam distribution function, wave spectral number density, total wave and particle energy density, and the beam number density. The main results of gas-dynamic theory are then compared with simulation results from numerical solutions of quasilinear equations. The relaxation of the beam in velocity space is retarded in the presence of density fluctuations and the magnitude of the upper velocity boundary is less than that in the absence of fluctuations. There are four different regimes for the height of the plateau, corresponding to different stages of relaxation of the beam in velocity space. Moreover, Langmuir scattering results in transfer of electrons from moderate velocity to low velocity; this effect produces an enhancement in the beam number density at small distances near the injection site and a corresponding decrease at large distances. There are sharp decreases in the profiles of the beam and total wave energy densities, which are related to dissipation of energy at large phase velocities. Due to a slower velocity space diffusion of the beam distribution in the presence of scattering effects, the spatial width of the beam is reduced while its mean velocity of propagation increases slightly.

  8. Access to a New Plasma Edge State with High Density and Pressures using Quiescent H-mode

    SciTech Connect (OSTI)

    Solomon, Wayne M. [PPPL; Snyder, P. B. [2General Atomics, P.O. Box 85608, San Diego, California 92186-5608, USA; Burrell, K. H. [2General Atomics, P.O. Box 85608, San Diego, California 92186-5608, USA; Fenstermacher, M. E. [LLNL; Garofalo, A. M. [2General Atomics, P.O. Box 85608, San Diego, California 92186-5608, USA; Grierson, B. A. [PPPL; Loarte, A. [ITER; McKee, G. R. [5University of Wisconsin-Madison, Madison, Wisconsin 53706, USA; Nazikian, R [PPPL; Osborne, T. H. [2General Atomics, P.O. Box 85608, San Diego, California 92186-5608, USA

    2014-07-01T23:59:59.000Z

    A path to a new high performance regime has been discovered in tokamaks that could improve the attractiveness of a fusion reactor. Experiments on DIII-D using a quiescent H-mode edge have navigated a valley of improved edge peeling-ballooning stability that opens up with strong plasma shaping at high density, leading to a doubling of the edge pressure over standard edge localized mode (ELM)ing H-mode at these parameters. The thermal energy confinement time increases both as a result of the increased pedestal height and improvements in the core transport and reduced low-k turbulence. Calculations of the pedestal height and width as a function of density using constraints imposed by peeling-ballooning and kinetic-ballooning theory are in quantitative agreement with the measurements.

  9. High density plasma damage in InGaP/GaAs as AlGaAs/GaAs high electron mobility transistors

    SciTech Connect (OSTI)

    Lee, J.W.; Pearton, S.J. [Univ. of Florida, Gainesville, FL (United States). Dept. of Materials Science and Engineering; Ren, F.; Kopf, R.F.; Kuo, J.M. [Bell Labs., Murray Hill, NJ (United States). Lucent Technologies; Shul, R.J. [Sandia National Labs., Albuquerque, NM (United States); Constantine, C.; Johnson, D. [Plasma-Therm Inc., St. Petersburg, FL (United States)

    1998-11-01T23:59:59.000Z

    The introduction of plasma damage in InGaP/GaAs and AlGaAs/GaAs high electron mobility transistors (HEMTs) has been investigated using both inductively coupled plasma and electron cyclotron resonance Ar discharges. The saturated drain-source current is found to be decreased through introduction of compensating deep levels into the InGaP or AlGaAs donor layer. The degradation of device performance is a strong function of ion energy and ion flux, and an advantage of both high density plasma tools is that ion energy can be reduced by increasing the plasma density. Increasing process pressure and source power, and decreasing radio-frequency chuck power produce the lowest amounts of plasma damage in HEMTs.

  10. Direct photoetching of polymers using radiation of high energy density from a table-top extreme ultraviolet plasma source

    SciTech Connect (OSTI)

    Barkusky, Frank; Bayer, Armin; Peth, Christian; Mann, Klaus [Laser-Laboratorium-Goettingen e.V., Hans-Adolf-Krebs-Weg 1, D-37077 Goettingen (Germany)

    2009-01-01T23:59:59.000Z

    In order to perform material interaction studies with intense extreme ultraviolet (EUV) radiation, a Schwarzschild mirror objective coated with Mo/Si multilayers was adapted to a compact laser-driven EUV plasma source utilizing a solid Au target. By 10x demagnified imaging of the plasma a maximum pulse energy density of {approx}0.73 J/cm{sup 2} at a wavelength of 13.5 nm can be achieved in the image plane of the objective at a pulse duration of 8.8 ns. In this paper we present EUV photoetching rates measured for polymethyl methacrylate, polycarbonate, and polytetrafluoroethylene at various fluence levels. A linear dependence between etch depth and applied EUV pulse number could be observed without the necessity for any incubation pulses. By evaluating the slope of these data, etch rates were determined, revealing also a linear behavior for low fluences. A threshold energy density could not be observed. The slope of the linear etch regime as well as deviations from the linear trend at higher energy densities are discussed and compared to data known from deep UV laser ablation. Furthermore, the surface roughness of the structured polymers was measured by atomic force microscopy and compared to the nonirradiated polymer surface, indicating a rather smooth etch process (roughness increase of 20%-30%). The different shapes of the etch craters observed for the three polymers at high energy densities can be explained by the measured fluence dependence of the etch rates, having consequences for the proper use of polymer ablation for beam profiling of focused EUV radiation.

  11. Electron density measurements of atmospheric-pressure non-thermal N{sub 2} plasma jet by Stark broadening and irradiance intensity methods

    SciTech Connect (OSTI)

    Xiao, Dezhi; Shen, Jie; Lan, Yan; Xie, Hongbing; Shu, Xingsheng; Meng, Yuedong; Li, Jiangang [Institute of Plasma Physics, Chinese Academy of Sciences, P. O. Box 1126, Hefei 230031 (China); Cheng, Cheng, E-mail: chengcheng@ipp.ac.cn, E-mail: paul.chu@cityu.edu.hk [Institute of Plasma Physics, Chinese Academy of Sciences, P. O. Box 1126, Hefei 230031 (China); Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China); Chu, Paul K., E-mail: chengcheng@ipp.ac.cn, E-mail: paul.chu@cityu.edu.hk [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China)

    2014-05-15T23:59:59.000Z

    An atmospheric-pressure non-thermal plasma jet excited by high frequency alternating current using nitrogen is developed and the electron density in the active region of this plasma jet is investigated by two different methods using optical emission spectroscopy, Stark broadening, and irradiance intensity method. The irradiance intensity method shows that the average electron density is about 10{sup 20}/m{sup 3} which is slightly smaller than that by the Stark broadening method. However, the trend of the change in the electron density with input power obtained by these two methods is consistent.

  12. Radiation from Ag high energy density Z-pinch plasmas and applications to lasing

    SciTech Connect (OSTI)

    Weller, M. E., E-mail: mweller@unr.edu; Safronova, A. S.; Kantsyrev, V. L.; Esaulov, A. A.; Shrestha, I.; Stafford, A.; Keim, S. F.; Shlyaptseva, V. V.; Osborne, G. C.; Petkov, E. E. [Physics Department, University of Nevada, Reno, Nevada 89557 (United States)] [Physics Department, University of Nevada, Reno, Nevada 89557 (United States); Apruzese, J. P.; Giuliani, J. L. [Naval Research Laboratory, Washington, District of Columbia 20375 (United States)] [Naval Research Laboratory, Washington, District of Columbia 20375 (United States); Chuvatin, A. S. [Ecole Polytechnique, 91128 Palaiseau (France)] [Ecole Polytechnique, 91128 Palaiseau (France)

    2014-03-15T23:59:59.000Z

    Silver (Ag) wire arrays were recently introduced as efficient x-ray radiators and have been shown to create L-shell plasmas that have the highest electron temperature (>1.8?keV) observed on the Zebra generator so far and upwards of 30?kJ of energy output. In this paper, results of single planar wire arrays and double planar wire arrays of Ag and mixed Ag and Al that were tested on the UNR Zebra generator are presented and compared. To further understand how L-shell Ag plasma evolves in time, a time-gated x-ray spectrometer was designed and fielded, which has a spectral range of approximately 3.5–5.0?Å. With this, L-shell Ag as well as cold L{sub ?} and L{sub ?} Ag lines was captured and analyzed along with photoconducting diode (PCD) signals (>0.8?keV). Along with PCD signals, other signals, such as filtered XRD (>0.2?keV) and Si-diodes (SiD) (>9?keV), are analyzed covering a broad range of energies from a few eV to greater than 53?keV. The observation and analysis of cold L{sub ?} and L{sub ?} lines show possible correlations with electron beams and SiD signals. Recently, an interesting issue regarding these Ag plasmas is whether lasing occurs in the Ne-like soft x-ray range, and if so, at what gains? To help answer this question, a non-local thermodynamic equilibrium (LTE) kinetic model was utilized to calculate theoretical lasing gains. It is shown that the Ag L-shell plasma conditions produced on the Zebra generator at 1.7 maximum current may be adequate to produce gains as high as 6?cm{sup ?1} for various 3p???3s transitions. Other potential lasing transitions, including higher Rydberg states, are also included in detail. The overall importance of Ag wire arrays and plasmas is discussed.

  13. List of Refereed Journal Publications 1. On the Existence of Moderate-Density-Burst Codes, Journal of Mathematical Sciences, Vol.

    E-Print Network [OSTI]

    Saidak, Filip

    List of Refereed Journal Publications 1. On the Existence of Moderate-Density-Burst Codes, Journal of Mathematical Sciences, Vol. 10, 8-12, 1975. 2. On UEP Burst Codes, Journal of Mathematical Sciences, Vol. 10, 21-27, 1975. 3. Linear Codes having a Sub-block Structure, Journal of Cybernetics, Vol. 6, 263

  14. High-Beta, Improved Confinement Reversed-Field Pinch Plasmas at High Density

    SciTech Connect (OSTI)

    Wyman, M. [University of Wisconsin, Madison; Chapman, B. E. [University of Wisconsin, Madison; Ahn, J. W. [University of Wisconsin, Madison; Almagri, A. [University of Wisconsin, Madison; Anderson, J. [University of Wisconsin, Madison; Bonomo, F. [Consorzio RFX, Italy; Brower, D. L. [University of California, Los Angeles; Combs, Stephen Kirk [ORNL; Craig, D. [University of Wisconsin, Madison; Hartog, D. J. Den [University of Wisconsin, Madison; Deng, B. [University of California, Los Angeles; Ding, W. X. [University of California, Los Angeles; Ebrahimi, F. [University of Wisconsin, Madison; Ennis, D. [University of Wisconsin, Madison; Fiksel, G. [University of Wisconsin, Madison; Foust, Charles R [ORNL; Franz, P. [EURATOM / ENEA, Italy; Gangadhara, S. [University of Wisconsin, Madison; Goetz, J. [University of Wisconsin, Madison; O'Connell, R, [University of Wisconsin, Madison; Oliva, S. [University of Wisconsin, Madison; Prager, S. C. [University of Wisconsin, Madison; Reusch, J. A. [University of Wisconsin, Madison; Sarff, J. S. [University of Wisconsin, Madison; Stephens, H. D. [University of Wisconsin, Madison; Yates, T. [University of California, Los Angeles

    2008-01-01T23:59:59.000Z

    In Madison Symmetric Torus Dexter et al., Fusion Technol. 19, 131 1991 discharges where improved confinement is brought about by modification of the current profile, pellet injection has quadrupled the density, reaching ne=41019 m 3. Without pellet injection, the achievable density in improved confinement discharges had been limited by edge-resonant tearing instability. With pellet injection, the total beta has been increased to 26%, and the energy confinement time is comparable to that at low density. Pressure-driven local interchange and global tearing are predicted to be linearly unstable. Interchange has not yet been observed experimentally, but there is possible evidence of pressure-driven tearing, an instability usually driven by the current gradient in the reversed-field pinch.

  15. High-{beta}, improved confinement reversed-field pinch plasmas at high density

    SciTech Connect (OSTI)

    Wyman, M. D.; Chapman, B. E.; Ahn, J. W.; Almagri, A. F.; Anderson, J. K.; Den Hartog, D. J.; Ebrahimi, F.; Ennis, D. A.; Fiksel, G.; Gangadhara, S.; Goetz, J. A.; O'Connell, R.; Oliva, S. P.; Prager, S. C.; Reusch, J. A.; Sarff, J. S.; Stephens, H. D. [Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Bonomo, F.; Franz, P. [Consorzio RFX, Corso Stati Uniti 4, 35127 Padova (Italy); Brower, D. L. [Department of Physics and Astronomy, University of California at Los Angeles, Los Angeles, California 90095-1594 (United States)] (and others)

    2008-01-15T23:59:59.000Z

    In Madison Symmetric Torus [Dexter et al., Fusion Technol. 19, 131 (1991)] discharges where improved confinement is brought about by modification of the current profile, pellet injection has quadrupled the density, reaching n{sub e}=4x10{sup 19} m{sup -3}. Without pellet injection, the achievable density in improved confinement discharges had been limited by edge-resonant tearing instability. With pellet injection, the total beta has been increased to 26%, and the energy confinement time is comparable to that at low density. Pressure-driven local interchange and global tearing are predicted to be linearly unstable. Interchange has not yet been observed experimentally, but there is possible evidence of pressure-driven tearing, an instability usually driven by the current gradient in the reversed-field pinch.

  16. A high-resolution imaging x-ray crystal spectrometer for high energy density plasmas

    SciTech Connect (OSTI)

    Chen, Hui, E-mail: chen33@llnl.gov, E-mail: bitter@pppl.gov; Magee, E.; Nagel, S. R.; Park, J.; Schneider, M. B.; Stone, G.; Williams, G. J.; Beiersdorfer, P. [Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550-9234 (United States); Bitter, M., E-mail: chen33@llnl.gov, E-mail: bitter@pppl.gov; Hill, K. W. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States); Kerr, S. [Department of Applied Science, University of Alberta, Edmonton, Alberta T6G 2R3 (Canada)

    2014-11-15T23:59:59.000Z

    Adapting a concept developed for magnetic confinement fusion experiments, an imaging crystal spectrometer has been designed and tested for HED plasmas. The instrument uses a spherically bent quartz [211] crystal with radius of curvature of 490.8 mm. The instrument was tested at the Titan laser at Lawrence Livermore National Laboratory by irradiating titanium slabs with laser intensities of 10{sup 19}–10{sup 20} W/cm{sup 2}. He-like and Li-like Ti lines were recorded, from which the spectrometer performance was evaluated. This spectrometer provides very high spectral resolving power (E/dE > 7000) while acquiring a one-dimensional image of the source.

  17. Electron density inside Enceladus plume inferred from plasma oscillations excited by dust impacts

    E-Print Network [OSTI]

    Gurnett, Donald A.

    1 Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa, USA, 2 LASP, University and electron spectrometers [Jones et al., 2009; Hill et al., 2012]. The nanoparticles appear as high-energy a sweeping voltage, and the ion and electron density can be inferred from the current balance. It is found

  18. Present Status and Future Prospects of Laser Fusion and Related High Energy Density Plasma Research

    SciTech Connect (OSTI)

    Mima, Kunioki [Institute of Laser Engineering, Osaka University, 2-6 Yamada-oka, Suita , Osaka, 565-0871 (Japan)

    2004-12-01T23:59:59.000Z

    The present status and future prospects of the laser fusion research and related laser plasma physics are reviewed. In laser fusion research, giant lasers for ignition and burn by imploding DT fuel pellets are under construction at LLNL (Lawrence Livermore National Laboratory) and CEA, France. In Japan , the Gekko XII and the Peta Watt laser system have been operated to investigate the implosion hydrodynamics, fast ignition, and the relativistic laser plasma interactions and a new project; FIREX( Fast Ignition Realization Experiment) had started toward the ignition and burn at the Institute of laser Engineering of Osaka University. Recently, heating experiments with cone shell target have been carried out. The thermal neutron yield is found to increase by three orders of magnitude by the peta watt laser injection to the cone shell target. The FIREX-I is planned according to this experimental results, where multi 10kJ peta watt laser is used to heat compressed DT fuel to the ignition temperature. The FIREX-II will follow for demonstrating ignition and burn, in which the implosion laser and heating laser are up-graded.

  19. Computational Support for Alternative Confinement Concepts Basic Plasma Science

    SciTech Connect (OSTI)

    Dalton D. Schnack

    2002-12-09T23:59:59.000Z

    This is the final report for contract DE-FG03-99ER54528, ''Computational Support for Alternative Confinement Concepts''. Progress was made in the following areas of investigation: (1) Extensive studies of the confinement properties of conventional Reversed-field Pinch (RFP) configurations (i.e., without current profile control) were performed in collaboration with the Royal Institute of Technology (KTH) in Stockholm, Sweden. These studies were carried out using the full 3-dimensional, finite-{beta}, resistive MHD model in the DEBS code, including ohmic heating and anisotropic heat conduction, and thus for the first time included the self-consistent effects of the dynamo magnetic fluctuations on the confinement properties of the RFP. By using multi-variant regression analysis of these results, scaling laws for various properties characterizing the conventional RFP were obtained. In particular, it was found that the, for constant ratio of I/N (where I is the current and N = na{sup 2} is the line density), and over a range of Lundquist numbers S that approaches 10{sup 6}, the fluctuations scale as {delta}B/B {approx} S{sup -0.14}, the temperature scales as T {approx} I{sup 0.56}, the poloidal beta scales as {beta}{sub {theta}} {approx} I{sup -0.4}, and the energy confinement time scales as {tau}{sub E} {approx} I{sup 0.34}. The degradation of poloidal beta with current is a result of the weak scaling of the fluctuation level with the Lundquist number, and leads to the unfavorable scaling laws for temperature and energy confinement time. These results compare reasonably well with experimental data, and emphasize the need for external control of the dynamo fluctuations in the RFP. (2) Studies of feedback stabilization of resistive wall modes in the RFP were performed with the DEBS code in collaboration with the CNR/RFX group in Padua, Italy. The ideal growth rates are ''passively'' reduced by the presence of a resistive wall within the radius for perfectly conducting wall stabilization of these modes. In this work we consider cases with up to two resistive walls. Moreover the feedback system is assumed to react to any given Fourier harmonic with an ideal response, in the sense that no spurious harmonics are generated. Successful feedback schemes are shown to be possible. However, a careful choice of the gains, along with the simultaneous feedback on at least 4 or 5 modes, is found to be necessary. (3) Studies of a stable rampdown operating regime for the RFP were performed in collaboration with Los Alamos National Laboratory and the University of Wisconsin. It was found that completely stable mean profiles can be obtained by properly tailoring the decaying time dependence of the toroidal current and magnetic flux. Deviations from optimal decay rates were shown to lead to single helicity (SH) and quasi-single helicity (QSH) states. In all cases the prospects for improved confinement properties were obtained. These results may account for the experimental observation of QSH states when the toroidal current is allowed to decay.

  20. INSTITUTE OF PHYSICS PUBLISHING PLASMA SOURCES SCIENCE AND TECHNOLOGY Plasma Sources Sci. Technol. 11 (2002) 273278 PII: S0963-0252(02)35617-2

    E-Print Network [OSTI]

    Chen, Francis F.

    2002-01-01T23:59:59.000Z

    of semiconductors, ionospheric plasma research, ion lasers, general plasma physics experiments, and plasma thruster

  1. DEGAS 2 Neutral Transport Modeling of High Density, Low Temperature Plasmas

    E-Print Network [OSTI]

    , the resulting fluid neutral momentum balance in a slab geometry is d dx ³ mnv 2 + nT ´ = # T n dT dx - m# cx nv.24, and the charge exchange frequency, # cx = 2.93# cx n(T/m) 1/2 . With a neutral source on one end of the slab (x density # # n(x)/n(L), d# dx = - 2 4 (1-# T ) T (L) dT (x) dx # + ##cx [T (L)/m] 1/2 T (x) T (L) - # 2 # 2

  2. MIT's Plasma Science Fusion Center: I-Mode Powers Up on Alcator C-Mod

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC)Integrated Codes |IsLove Your Home and It'll Love YouTokamak | Princeton Plasma

  3. Demonstration of x-ray fluorescence imaging of a high-energy-density plasma

    SciTech Connect (OSTI)

    MacDonald, M. J., E-mail: macdonm@umich.edu; Gamboa, E. J. [Department of Atmospheric, Oceanic, and Space Sciences, University of Michigan, Ann Arbor, Michigan 48109 (United States); SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Keiter, P. A.; Fein, J. R.; Klein, S. R.; Kuranz, C. C.; LeFevre, H. J.; Manuel, M. J.-E.; Wan, W. C.; Drake, R. P. [Department of Atmospheric, Oceanic, and Space Sciences, University of Michigan, Ann Arbor, Michigan 48109 (United States); Montgomery, D. S. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Biener, M. M.; Fournier, K. B. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Streit, J. [Schafer Corporation, Livermore, California 94551 (United States)

    2014-11-15T23:59:59.000Z

    Experiments at the Trident Laser Facility have successfully demonstrated the use of x-ray fluorescence imaging (XRFI) to diagnose shocked carbonized resorcinol formaldehyde (CRF) foams doped with Ti. One laser beam created a shock wave in the doped foam. A second laser beam produced a flux of vanadium He-? x-rays, which in turn induced Ti K-shell fluorescence within the foam. Spectrally resolved 1D imaging of the x-ray fluorescence provided shock location and compression measurements. Additionally, experiments using a collimator demonstrated that one can probe specific regions within a target. These results show that XRFI is a capable alternative to path-integrated measurements for diagnosing hydrodynamic experiments at high energy density.

  4. Quark spectral density and a strongly-coupled quark-gluon plasma.

    SciTech Connect (OSTI)

    Qin, S.; Chang, L.; Liu, Y.; Roberts, C. D. (Physics); (Peking Univ.); (Inst. of Applied Physics and Computational Mathematics); (National Lab. of Heavy Ion Accelerator)

    2011-07-13T23:59:59.000Z

    The maximum entropy method is used to compute the dressed-quark spectral density from the self-consistent numerical solution of a rainbow truncation of QCD's gap equation at temperatures above that for which chiral symmetry is restored. In addition to the normal and plasmino modes, the spectral function also exhibits an essentially nonperturbative zero mode for temperatures extending to 1.4-1.8 times the critical temperature, T{sub c}. In the neighborhood of T{sub c}, this long-wavelength mode contains the bulk of the spectral strength and as long as this mode persists, the system may fairly be described as a strongly-coupled state of matter.

  5. Laser-induced fluorescence measurements on plasma science experiments at PPPL

    SciTech Connect (OSTI)

    Koepke, Mark

    2011-12-20T23:59:59.000Z

    Collaborative research between WVU and PPPL was carried out at WVU for the purpose of incorporating the sophisticated diagnostic technique known as laser-induced fluorescence (LIF) in the Paul-Trap Simulation Experiment (PTSX) at PPPL. WVU assembled a LIF system at WVU, transported it to PPPL, helped make LIF experiments on the PTSX device, participated in PTSX science, and trained PPPL staff in LIF techniques. In summary, WVU refurbished a non-operational LIF system being loaned from University of Maryland to PPPL and, by doing so, provided PPPL with additional diagnostic capability for its PTSX device and other General Plasma Science experiments. WVU students, staff, and faculty will visit PPPL to collaborate on PTSX experiments in the future.

  6. Heavy ion fusion science research for high energy density physics and fusion applications

    E-Print Network [OSTI]

    Logan, B.G.

    2007-01-01T23:59:59.000Z

    long final-focus solenoid filled with plasma was modeled (final-focus solenoid. In this simulation, plasma is assumedplasma source (FEPS) which neutralizes the longitudinal drift compression region, 5T final focus

  7. Science on Saturday attracts science fans of all ages | Princeton Plasma

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's PossibleRadiationImplementingnpitcheResearch BriefsTenney,Science and TechnologyResearchPhysics

  8. 694 IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 34, NO. 3, JUNE 2006 Guest Editorial

    E-Print Network [OSTI]

    Kaganovich, Igor

    -temperature, fu- sion plasmas and low-temperature, gas discharge plasmas. Such low-pressure plasmas have dynamics in plasmas, particularly in glow discharges, plasma sources for material processing, and plasma. Therefore, it is important to summarize the current state-of-the-art for both communities in one volume. Low

  9. Absolute atomic oxygen and nitrogen densities in radio-frequency driven atmospheric pressure cold plasmas: Synchrotron vacuum ultra-violet high-resolution Fourier-transform absorption measurements

    SciTech Connect (OSTI)

    Niemi, K.; O'Connell, D.; Gans, T. [York Plasma Institute, Department of Physics, University of York, York YO10 5DD (United Kingdom); Oliveira, N. de; Joyeux, D.; Nahon, L. [Synchrotron Soleil, l'Orme des Merisiers, St. Aubin BP 48, 91192 Gif sur Yvette Cedex (France); Booth, J. P. [Laboratoire de Physique des Plasmas-CNRS, Ecole Polytechnique, 91128 Palaiseau (France)

    2013-07-15T23:59:59.000Z

    Reactive atomic species play a key role in emerging cold atmospheric pressure plasma applications, in particular, in plasma medicine. Absolute densities of atomic oxygen and atomic nitrogen were measured in a radio-frequency driven non-equilibrium plasma operated at atmospheric pressure using vacuum ultra-violet (VUV) absorption spectroscopy. The experiment was conducted on the DESIRS synchrotron beamline using a unique VUV Fourier-transform spectrometer. Measurements were carried out in plasmas operated in helium with air-like N{sub 2}/O{sub 2} (4:1) admixtures. A maximum in the O-atom concentration of (9.1 {+-} 0.7) Multiplication-Sign 10{sup 20} m{sup -3} was found at admixtures of 0.35 vol. %, while the N-atom concentration exhibits a maximum of (5.7 {+-} 0.4) Multiplication-Sign 10{sup 19} m{sup -3} at 0.1 vol. %.

  10. Behaviour and stability of Trivelpiece-Gould modes in non-neutral plasma containing small density fraction of background gas ions

    SciTech Connect (OSTI)

    Yeliseyev, Y. N. [Institute of Plasma Physics, National Science Center Kharkov Institute of Physics and Technology, Akademicheskaya St., 1, 61108 Kharkov (Ukraine)

    2013-03-19T23:59:59.000Z

    It is shown that the frequencies of Trivelpiece-Gould (TG) modes in non-neutral plasma can get into the low-frequency range due to the Doppler shift caused by plasma rotation in crossed fields. TG modes interact with the ion modes that leads to plasma instability. In paper the frequency spectrum of 'cold' electron plasma completely filling a waveguide and containing small density fraction of ions of background gas is determined numerically. For ions the kinetic description is used. Oscillations having azimuthal number m= 2 are considered. In this case both low- and upper-hybrid TG modes get into the low-frequency range. The spectrum consists of families of 'modified' ion cyclotron (MIC) modes and electron TG modes with the frequencies equal to hybrid frequencies with the Doppler shift. The growth rates of upper-hybrid modes are much faster than the growth rates of low-hybrid and MIC modes.

  11. Reduction of plasma density in the Helicity Injected Torus with Steady Inductance experiment by using a helicon pre-ionization source

    SciTech Connect (OSTI)

    Hossack, Aaron C.; Jarboe, Thomas R.; Victor, Brian S. [Department of Aeronautics and Astronautics, University of Washington, Seattle, Washington 98195 (United States)] [Department of Aeronautics and Astronautics, University of Washington, Seattle, Washington 98195 (United States); Firman, Taylor; Prager, James R.; Ziemba, Timothy [Eagle Harbor Technologies, Inc., 119 W. Denny Way, Suite 210, Seattle, Washington 98119 (United States)] [Eagle Harbor Technologies, Inc., 119 W. Denny Way, Suite 210, Seattle, Washington 98119 (United States); Wrobel, Jonathan S. [979B West Moorhead Circle, Boulder, Colorado 80305 (United States)] [979B West Moorhead Circle, Boulder, Colorado 80305 (United States)

    2013-10-15T23:59:59.000Z

    A helicon based pre-ionization source has been developed and installed on the Helicity Injected Torus with Steady Inductance (HIT-SI) spheromak. The source initiates plasma breakdown by injecting impurity-free, unmagnetized plasma into the HIT-SI confinement volume. Typical helium spheromaks have electron density reduced from (2–3) × 10{sup 19} m{sup ?3} to 1 × 10{sup 19} m{sup ?3}. Deuterium spheromak formation is possible with density as low as 2 × 10{sup 18} m{sup ?3}. The source also enables HIT-SI to be operated with only one helicity injector at injector frequencies above 14.5 kHz. A theory explaining the physical mechanism driving the reduction of breakdown density is presented.

  12. MICROCAVITYMICROCAVITY PLASMA SCIENCE AND RECENTPLASMA SCIENCE AND RECENT APPLICATIONS: BOUNDAPPLICATIONS: BOUND--FREE COUPLING, TRANSISTORFREE COUPLING, TRANSISTOR

    E-Print Network [OSTI]

    Shyy, Wei

    Electrode Glass6 mm 250 m LED Backlight Microcavity Lamp #12;OPERATION OF MICROCAVITY PLASMA DEVICES Plasma Surface Treatment High Intensity Plasma Arc Lamp Spark Gap Plasma Display (150 inch Panasonic ) Ozone generator Fluorescent Lamp Gas Laser #12;University of Illinois Laboratory for Optical Physics

  13. Ultrafast dynamics of a near-solid-density layer in an intense femtosecond laser-excited plasma

    SciTech Connect (OSTI)

    Adak, Amitava; Chatterjee, Gourab; Kumar Singh, Prashant; Lad, Amit D.; Brijesh, P.; Kumar, G. Ravindra, E-mail: grk@tifr.res.in [Tata Institute of Fundamental Research, Dr. Homi Bhabha Road, Colaba, Mumbai 400005 (India); Blackman, David R. [York Plasma Institute, University of York, Heslington, York YO10 5DQ (United Kingdom); Robinson, A. P. L. [Central Laser Facility, Rutherford-Appleton Laboratory, Chilton, Didcot OX10 0QX (United Kingdom); Pasley, John [York Plasma Institute, University of York, Heslington, York YO10 5DQ (United Kingdom); Central Laser Facility, Rutherford-Appleton Laboratory, Chilton, Didcot OX10 0QX (United Kingdom)

    2014-06-15T23:59:59.000Z

    We report on the picosecond dynamics of a near-solid-density plasma generated by an intense, infrared (??=?800?nm) femtosecond laser using time-resolved pump-probe Doppler spectrometry. An initial red-shift is observed in the reflected third harmonic (??=?266?nm) probe pulse, which gets blue-shifted at longer probe-delays. A combination of particle-in-cell and radiation-hydrodynamics modelling is performed to model the pump laser interaction with the solid target. The results are post-processed to predict the Doppler shift. An excellent agreement is found between the results of such modelling and the experiment. The modelling suggests that the initial inward motion of the critical surface observed in the experiment is due to the passage of a shock-wave-like disturbance, launched by the pump interaction, propagating into the target. Furthermore, in order to achieve the best possible fit to the experimental data, it was necessary to incorporate the effects of bulk ion-acceleration resulting from the electrostatic field set up by the expulsion of electrons from the laser envelope. We also present results of time-resolved pump-probe reflectometry, which are corroborated with the spectrometry results using a 1-D reflectivity model.

  14. Spatially resolved measurements of ion density and electron temperature in a dual-frequency capacitively coupled plasma by complete floating double probe technique

    SciTech Connect (OSTI)

    Jiang Xiangzhan; Liu Yongxin; Yang Shuo; Lu Wenqi; Bi Zhenhua; Li Xiaosong; Wang Younian [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China)

    2011-01-15T23:59:59.000Z

    Spatially resolved measurements of the ion density and electron temperature in a dual-frequency capacitively coupled Ar discharge plasma are performed with a newly developed complete floating double probe. Axial and radial distributions of the ion density and electron temperature under various high-frequency (HF) power and gas pressure were studied in detail. Both the ion density and the electron temperature increased with increasing HF power. With increasing gas pressure from 1.3 to 9.3 Pa, the radial profile of ion density below the driven electrode experienced a change from ''bimodal'' to ''unimodal'' shape, with better uniformity being achieved at the optimal pressure of about 5 Pa. In addition, changing the axial profile of ion density was also observed with the peak shift toward the powered electrode at higher pressures. The measured results showed satisfying consistency with that of improved two dimensional fluid simulations.

  15. 2490 IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 39, NO. 11, NOVEMBER 2011 New Wave Effects in Compressing Plasma

    E-Print Network [OSTI]

    waves in compressing plasma first grow and then abruptly transfer energy to particles or fields. Index in Compressing Plasma P. F. Schmit, I. Y. Dodin, and N. J. Fisch Abstract--A new mechanism is predicted whereby compres- sion or ionization, embedded waves are affected. For compression that is slow compared

  16. 2566 IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 36, NO. 5, OCTOBER 2008 Quantitative Analysis of Gas Circuit Breaker

    E-Print Network [OSTI]

    Basse, Nils Plesner

    --Understanding the dynamic processes governing gas circuit breaker physics is crucial in order to continue to improve short, especially those induced at flow reversal where the gas flow between the arc zone and heating volume changes2566 IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 36, NO. 5, OCTOBER 2008 Quantitative Analysis of Gas

  17. 2512 IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 36, NO. 5, OCTOBER 2008 Experimental Investigation of 193-nm

    E-Print Network [OSTI]

    Scharer, John E.

    2512 IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 36, NO. 5, OCTOBER 2008 Experimental Investigation of 193-nm Laser Breakdown in Air Magesh Thiyagarajan, Member, IEEE, and John E. Scharer, Senior Member, IEEE Abstract--We present the measurements and analysis of laser- induced breakdown processes in dry

  18. IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 36, NO. 5, OCTOBER 2008 2095 Permanent Magnet Helicon Source for Ion Propulsion

    E-Print Network [OSTI]

    Chen, Francis F.

    IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 36, NO. 5, OCTOBER 2008 2095 Permanent Magnet Helicon Source for Ion Propulsion Francis F. Chen, Life Fellow, IEEE Abstract--Helicon sources have been proposed by at least two groups for generating ions for space propulsion: the Helicon Dou- ble Layer Thruster (HDLT

  19. MIT Plasma Science & Fusion Center: research>alcator>introduction

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC)Integrated Codes |IsLove Your Home and It'll Love You BackTechnology &Density

  20. Al{sub 2}O{sub 3} multi-density layer structure as a moisture permeation barrier deposited by radio frequency remote plasma atomic layer deposition

    SciTech Connect (OSTI)

    Jung, Hyunsoo [Division of Materials Science and Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Samsung Display Co. Ltd., Tangjeong, Chungcheongnam-Do 336-741 (Korea, Republic of); Jeon, Heeyoung [Department of Nano-scale Semiconductor Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Choi, Hagyoung; Ham, Giyul; Shin, Seokyoon [Division of Materials Science and Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Jeon, Hyeongtag, E-mail: hjeon@hanyang.ac.kr [Division of Materials Science and Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Department of Nano-scale Semiconductor Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of)

    2014-02-21T23:59:59.000Z

    Al{sub 2}O{sub 3} films deposited by remote plasma atomic layer deposition have been used for thin film encapsulation of organic light emitting diode. In this study, a multi-density layer structure consisting of two Al{sub 2}O{sub 3} layers with different densities are deposited with different deposition conditions of O{sub 2} plasma reactant time. This structure improves moisture permeation barrier characteristics, as confirmed by a water vapor transmission rate (WVTR) test. The lowest WVTR of the multi-density layer structure was 4.7 × 10{sup ?5} gm{sup ?2} day{sup ?1}, which is one order of magnitude less than WVTR for the reference single-density Al{sub 2}O{sub 3} layer. This improvement is attributed to the location mismatch of paths for atmospheric gases, such as O{sub 2} and H{sub 2}O, in the film due to different densities in the layers. This mechanism is analyzed by high resolution transmission electron microscopy, elastic recoil detection, and angle resolved X-ray photoelectron spectroscopy. These results confirmed that the multi-density layer structure exhibits very good characteristics as an encapsulation layer via location mismatch of paths for H{sub 2}O and O{sub 2} between the two layers.

  1. IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 40, NO. 5, MAY 2012 1265 Guest Editorial: Special Issue on Plenary and

    E-Print Network [OSTI]

    Harilal, S. S.

    ) charged particle beams and sources; 4) high- energy-density plasma applications; 5) industrial, commercial energy, coherent light sources, flat-panel displays, coatings, surface modification, microscopic) received the B.Sc. and M.Sc. degrees in nuclear engineering from Alexandria University, Alexandria, Egypt

  2. The National Ignition Facility: The Path to Ignition, High Energy Density Science and Inertial Fusion Energy

    SciTech Connect (OSTI)

    Moses, E

    2011-03-25T23:59:59.000Z

    The National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory (LLNL) in Livermore, CA, is a Nd:Glass laser facility capable of producing 1.8 MJ and 500 TW of ultraviolet light. This world's most energetic laser system is now operational with the goals of achieving thermonuclear burn in the laboratory and exploring the behavior of matter at extreme temperatures and energy densities. By concentrating the energy from its 192 extremely energetic laser beams into a mm{sup 3}-sized target, NIF can produce temperatures above 100 million K, densities of 1,000 g/cm{sup 3}, and pressures 100 billion times atmospheric pressure - conditions that have never been created in a laboratory and emulate those in the interiors of planetary and stellar environments. On September 29, 2010, NIF performed the first integrated ignition experiment which demonstrated the successful coordination of the laser, the cryogenic target system, the array of diagnostics and the infrastructure required for ignition. Many more experiments have been completed since. In light of this strong progress, the U.S. and the international communities are examining the implication of achieving ignition on NIF for inertial fusion energy (IFE). A laser-based IFE power plant will require a repetition rate of 10-20 Hz and a 10% electrical-optical efficiency laser, as well as further advances in large-scale target fabrication, target injection and tracking, and other supporting technologies. These capabilities could lead to a prototype IFE demonstration plant in 10- to 15-years. LLNL, in partnership with other institutions, is developing a Laser Inertial Fusion Energy (LIFE) baseline design and examining various technology choices for LIFE power plant This paper will describe the unprecedented experimental capabilities of the NIF, the results achieved so far on the path toward ignition, the start of fundamental science experiments and plans to transition NIF to an international user facility providing access to researchers around the world. The paper will conclude with a discussion of LIFE, its development path and potential to enable a carbon-free clean energy future.

  3. Heavy ion fusion science research for high energy density physics and fusion applications

    E-Print Network [OSTI]

    Logan, B.G.

    2007-01-01T23:59:59.000Z

    cost direct plasma MHD direct conversion [38], as well as toT-lean targets and direct conversion for heavy ion fusion. [conversion loss of beam energy into x-rays. High ablation velocities with heavy ion direct

  4. Electronic temperatures, densities, and plasma x-ray emission of a 14.5 GHz electron-cyclotron resonance ion source

    SciTech Connect (OSTI)

    Gumberidze, A.; Szabo, C. I.; Indelicato, P.; Isac, J.-M.; Le Bigot, E.-O. [Laboratoire Kastler Brossel, Ecole Normale Superieure, CNRS, Universite Pierre et Marie Curie-Paris 6 Case 74, 4, Place Jussieu, 75252 Paris Cedex 05 (France); Trassinelli, M.; Adrouche, N.; Haranger, F.; Lamour, E.; Merot, J.; Prigent, C.; Rozet, J.-P.; Vernhet, D. [Institut des NanoSciences de Paris, CNRS, Universite Pierre et Marie Curie-Paris 6, Campus Boucicaut, 140 rue de Lourmel, 75015 Paris (France)

    2010-03-15T23:59:59.000Z

    We have performed a systematic study of the bremsstrahlung emission from the electrons in the plasma of a commercial 14.5 GHz electron-cyclotron resonance ion source. The electronic spectral temperature and the product of ionic and electronic densities of the plasma are measured by analyzing the bremsstrahlung spectra recorded for several rare gases (Ar, Kr, and Xe) as a function of the injected power. Within our uncertainty, we find an average temperature of {approx_equal}48 keV above 100 W, with a weak dependency on the injected power and gas composition. Charge state distributions of extracted ion beams have been determined as well, providing a way to disentangle the ionic density from the electronic density. Moreover x-ray emission from highly charged argon ions in the plasma has been observed with a high-resolution mosaic-crystal spectrometer, demonstrating the feasibility for high-precision measurements of transition energies of highly charged ions, in particular, of the magnetic dipole (M1) transition of He-like of argon ions.

  5. Relativistic self-focusing of ultra-high intensity X-ray laser beams in warm quantum plasma with upward density profile

    SciTech Connect (OSTI)

    Habibi, M., E-mail: habibi.physics@gmail.com [Young Researchers and Elite Club, Shirvan Branch, Islamic Azad University, Shirvan (Iran, Islamic Republic of); Ghamari, F. [Young Researchers and Elite Club, Khorramabad Branch, Islamic Azad University, Khorramabad (Iran, Islamic Republic of)

    2014-05-15T23:59:59.000Z

    The results of a numerical study of high-intensity X-ray laser beam interaction with warm quantum plasma (WQP) are presented. By means of an upward ramp density profile combined with quantum factors specially the Fermi velocity, we have demonstrated significant relativistic self-focusing (RSF) of a Gaussian electromagnetic beam in the WQP where the Fermi temperature term in the dielectric function is important. For this purpose, we have considered the quantum hydrodynamics model that modifies refractive index of inhomogeneous WQPs with the inclusion of quantum correction through the quantum statistical and diffraction effects in the relativistic regime. Also, to better illustration of the physical difference between warm and cold quantum plasmas and their effect on the RSF, we have derived the envelope equation governing the spot size of X-ray laser beam in Q-plasmas. In addition to the upward ramp density profile, we have found that the quantum effects would be caused much higher oscillation and better focusing of X-ray laser beam in the WQP compared to that of cold quantum case. Our computational results reveal the importance of the use of electrons density profile and Fermi speed in enhancing self-focusing of laser beam.

  6. Influence of the reactor wall composition on radicals' densities and total pressure in Cl{sub 2} inductively coupled plasmas: II. During silicon etching

    SciTech Connect (OSTI)

    Cunge, G.; Sadeghi, N.; Ramos, R. [Laboratoire des Technologies de la Microelectronique, CNRS, 17 rue des Martyrs (c/o CEA-LETI), 38054 Grenoble Cedex 9 (France); Laboratoire de Spectrometrie Physique (UMR 5588), Universite Joseph Fourier-Grenoble, and CNRS, BP 87, 38402 St. Martin d'Heres (France); Laboratoire des Technologies de la Microelectronique, CNRS, 17 rue des Martyrs (c/o CEA-LETI), 38054 Grenoble Cedex 9 (France)

    2007-11-01T23:59:59.000Z

    In an industrial inductively coupled plasma reactor dedicated to silicon etching in chlorine-based chemistry, the density of Cl{sub 2} molecules and the gas temperature are measured by means of laser absorption techniques, the density of SiCl{sub x} (x{<=}2) radicals by broadband absorption spectroscopy, the density of SiCl{sub 4} and ions by mass spectrometry, and the total gas pressure with a capacitance gauge. These measurements permit us to estimate the mole fractions of Cl, SiCl{sub 4}, and etch product radicals when etching a 200 mm diameter silicon wafer. The pure Cl{sub 2} plasma is operated in well prepared chamber wall coating with a thin film of SiOCl, AlF, CCl, or TiOCl. The impact of the chemical nature of the reactor wall's coatings on these mole fractions is studied systematically. We show that the reactor wall coatings have a huge influence on the radicals densities, but this is not only from the difference on Cl-Cl recombination coefficient on different surfaces. During silicon etching, SiCl{sub x} radicals sticking on the reactor walls are etched by Cl atoms and recycled into the plasma by forming volatile SiCl{sub 4}. Hence, the loss of Cl atoms in etching the wall deposited silicon is at least as important as their wall recombination in controlling the Cl atoms density. Furthermore, because SiCl{sub 4} is produced at high rate by both the wafer and reactor walls, it is the predominant etching product in the gas phase. However, the percentage of redeposited silicon that can be recycled into the plasma depends on the amount of oxygen present in the plasma: O atoms produced by etching the quartz roof window fix Si on the reactor walls by forming a SiOCl deposit. Hence, the higher the O density is, the lower the SiCl{sub 4} density will be, because silicon is pumped by the reactor walls and the SiOCl layer formed is not isotropically etched by chlorine. As a result, in the same pure Cl{sub 2} plasma at 20 mTorr, the SiCl{sub x} mole fraction can vary from 18% in a SiOCl-coated reactor, where the O density is the highest, to 62% in a carbon-coated reactor, where there is no O. In the latter case, most of the Cl mass injected in the reactor is stored in SiCl{sub 4} molecules, which results in a low silicon etch rate. In this condition, the Cl mass balance is verified within 10%, and from the silicon mass balance we concluded that SiCl{sub x} radicals have a high surface loss probability. The impact of the reactor wall coating on the etching process is thus important, but the mechanisms by which the walls control the plasma chemistry is much more complicated than a simple control through recombination reaction of halogen atoms on these surfaces.

  7. Space and time resolved spectroscopy of laser-produced plasmas: A study of density-sensitive x-ray transitions in helium-like and neon-like ions

    SciTech Connect (OSTI)

    Young, Bruce Kai Fong

    1988-09-01T23:59:59.000Z

    The determination of level populations and detailed population mechanisms in dense plasmas has become an increasingly important problem in atomic physics. In this work, the density variation of line intensities and level populations in aluminum K-shell and molybdenum and silver L-shell emission spectra have been measured from high-powered, laser-produced plasmas. For each case, the density dependence of the observed line emission is due to the effect of high frequency electron-ion collisions on metastable levels. The density dependent line intensities vary greatly in laser-produced plasmas and can be used to extract detailed information concerning the population kinetics and level populations of the ions. The laser-plasmas had to be fully characterized in order to clearly compare the observed density dependence with atomic theory predictions. This has been achieved through the combined use of new diagnostic instruments and microdot targets which provided simultaneously space, time, and spectrally resolved data. The plasma temperatures were determined from the slope of the hydrogen-like recombination continuum. The time resolved electron density profiles were measured using multiple frame holographic interferometry. Thus, the density dependence of K-shell spectral lines could be clearly examined, independent of assumptions concerning the dynamics of the plasma. In aluminum, the electron density dependence of various helium-like line intensity ratios were measured. Standard collisional radiative equilibrium models fail to account for the observed density dependence measured for the ''He/sub ..cap alpha..//IC'' ratio. Instead, a quasi-steady state atomic model based on a purely recombining plasma is shown to accurately predict the measured density dependence. This same recombining plasma calculation successfully models the density dependence of the high-n ''He/sub ..gamma..//He/sub ..beta../'' and ''He/sub delta//He/sub ..beta../'' helium-like resonance line intensity ratios.

  8. Influence of the reactor wall composition on radicals' densities and total pressure in Cl{sub 2} inductively coupled plasmas: I. Without silicon etching

    SciTech Connect (OSTI)

    Cunge, G.; Sadeghi, N.; Ramos, R. [Laboratoire des Technologies de la Microelectronique, CNRS, 17 rue des Martyrs (c/o CEA-LETI), 38054 Grenoble Cedex 9 (France); Laboratoire de Spectrometrie Physique (UMR 5588), Universite Joseph Fourier-Grenoble, and CNRS, BP 87, 38402 St. Martin d'Heres (France); Laboratoire des Technologies de la Microelectronique, CNRS, 17 rue des Martyrs (c/o CEA-LETI), 38054 Grenoble Cedex 9 (France)

    2007-11-01T23:59:59.000Z

    Laser absorption at 355 nm is used to monitor the time variations of the Cl{sub 2} density in high-density industrial inductively coupled plasma. This technique is combined with the measurement of the gas temperature from the Doppler width of the 811.5 nm line of argon, added as a trace gas and with the measurement of the total gas pressure with a Baratron gauge. These measurements permit to estimate the mole fractions of Cl{sub 2} and Cl species in Cl{sub 2} inductively coupled plasmas in a waferless reactor. The impact of the chemical nature of the reactor wall coatings on the Cl and Cl{sub 2} mole fractions is studied systematically. We show that under otherwise identical plasma conditions, the Cl mole fraction is completely different when the plasma is operated in SiOCl, AlF, CCl, or TiOCl coated reactors, because the homogeneous recombination probability of Cl atoms is strongly surface dependant. The Cl atom mole fraction reached at 100 W radiofrequency power in SiOCl coated reactor (80%) is much higher than that obtained at 900 W in a ''clean'' AlF reactor (40%). A simple zero-dimensional model permits to provide the recombination coefficient of Cl atoms, {gamma}{sub rec}: 0.005 on SiOCl film and about 0.3 on the other three coatings. It is proposed to get benefit of this very high sensitivity of Cl{sub 2} dissociation rate to the wall coating for the control of the chamber wall status from the Cl{sub 2} density measurements in standard conditions.

  9. 2392 IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 39, NO. 1, NOVEMBER 2011 Evolution of MHD Instabilities in Plasma

    E-Print Network [OSTI]

    Kroupp, Eyal

    (Z-pinch), revealed ringlike instabilities followed by the development of axially and azimuthally radial velocities. Index Terms--Plasma implosion, visible imaging, Z-pinch. THE Z-PINCH implosions serve­Israeli Institute of Technology, Haifa 32000, Israel (e-mail: amnon.fisher@gmail.com). E. Yu is with the Sandia

  10. IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 34, NO. 3, JUNE 2006 825 Nonlocal Effects in a Bounded Afterglow Plasma

    E-Print Network [OSTI]

    Kaganovich, Igor

    excitation, supply additional heating to slow electrons and reduce their diffu- sion cooling rate. Altering research and technical applications. Index Terms--Afterglow plasma, diffusion cooling, electron energy and diffusion cooling, much faster than the characteristic recombination time of the electrons. Due

  11. 474 IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 33, NO. 2, APRIL 2005 Fast Photography of a Laser Generated Plasma

    E-Print Network [OSTI]

    Harilal, S. S.

    . Bindhu, and F. Najmabadi Abstract--The dynamics and confinement of laser generated Carbon plumes. Photographic studies showed the collapse of the ablation plume after the bubble lifetime, and formation of two graphitic carbon plasmas expanding across a transverse magnetic field have been investigated using fast

  12. 1202 IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 36, NO. 4, AUGUST 2008 Controlling the Plasma Potential Distribution in

    E-Print Network [OSTI]

    --Hall discharge, plasma propulsion. I. INTRODUCTION THE HALL thruster (HT) [1] is an electromagnetic- propulsion along the magnetic-field lines (E = -ve × B) accelerates ions and gen- erates thrust. Ions HTs, the electric-field distribution is con- trolled mainly by the magnetic-field distribution

  13. 1998 IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 36, NO. 5, OCTOBER 2008 Controlling the Plasma Flow in the

    E-Print Network [OSTI]

    Terms--Cross-field discharge, Langmuir probe, magnetic mirror, plasma thruster. NOMENCLATURE B Magnetic efficiency. c Electron gyrofrequency. I. INTRODUCTION THE HALL thruster [1] is a mature electric propulsion://ieeexplore.ieee.org. Digital Object Identifier 10.1109/TPS.2008.2002148 Fig. 1. Schematic of a CHT. Superimposed magnetic

  14. 10 IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 30, NO. 1, FEBRUARY 2002 Study of Magnetic Helicity Injection via Plasma

    E-Print Network [OSTI]

    Hsu, Scott

    , spheromak. MAGNETIC helicity [1] is a quantity which describes the amount of twist or writhe in the magnetic-confined plasmas in fusion research (e.g., spheromaks) must be sustained somehow, i.e., via helicity injection a schematic of the experimental setup. A coaxial spheromak gun with large planar geometry is installed on one

  15. Influence of plasma density on the chemical composition and structural properties of pulsed laser deposited TiAlN thin films

    SciTech Connect (OSTI)

    Quiñones-Galván, J. G.; Camps, Enrique [Departamento de Física, Instituto Nacional de Investigaciones Nucleares, Apartado Postal 18-1027, México D.F. C.P. 11801 (Mexico); Muhl, S. [Instituto de Investigaciones en Materiales, UNAM, México D.F. C.P. 04510 (Mexico); Flores, M. [Departamento de Ingeniería de Proyectos, CUCEI, Universidad de Guadalajara, Apdo. Postal 307, C.P. 45101 Zapopan, Jalisco (Mexico); Campos-González, E. [Departamento de Física, CINVESTAV-IPN, Apdo. Postal 14-740, México D.F. 07360 (Mexico)

    2014-05-15T23:59:59.000Z

    Incorporation of substitutional Al into the TiN lattice of the ternary alloy TiAlN results in a material with improved properties compared to TiN. In this work, TiAlN thin films were grown by the simultaneous ablation of Ti and Al targets in a nitrogen containing reactive atmosphere. The deposit was formed on silicon substrates at low deposition temperature (200?°C). The dependence of the Al content of the films was studied as a function of the ion density of the plasma produced by the laser ablation of the Al target. The plasma parameters were measured by means of a planar Langmuir probe and optical emission spectroscopy. The chemical composition of the films was measured by energy dispersive X-ray spectroscopy. The results showed a strong dependence of the amount of aluminum incorporated in the films with the plasma density. The structural characterization of the deposits was carried out by Raman spectroscopy, X-ray diffraction, and transmission electron microscopy, where the substitutional incorporation of the Al into the TiN was demonstrated.

  16. Large Scale Computing and Storage Requirements for Fusion Energy Sciences Research

    E-Print Network [OSTI]

    Gerber, Richard

    2012-01-01T23:59:59.000Z

    basic plasma science, including both burning plasma and low temperature plasma science and engineering, to enhance economic

  17. INSTITUTE OF PHYSICS PUBLISHING PLASMA SOURCES SCIENCE AND TECHNOLOGY Plasma Sources Sci. Technol. 16 (2007) 233239 doi:10.1088/0963-0252/16/2/004

    E-Print Network [OSTI]

    Choueiri, Edgar

    -pinch [3], spheromak [4] and plasma opening switch [5]. The plasma source used here is very repeatable [6

  18. Development of a high dynamic range spectroscopic system for observation of neutral hydrogen atom density distribution in Large Helical Device core plasma

    SciTech Connect (OSTI)

    Fujii, K., E-mail: fujii@me.kyoto-u.ac.jp; Atsumi, S.; Watanabe, S.; Shikama, T.; Hasuo, M. [Department of Mechanical Engineering and Science, Graduate School of Engineering, Kyoto University, Kyoto 606-8540 (Japan)] [Department of Mechanical Engineering and Science, Graduate School of Engineering, Kyoto University, Kyoto 606-8540 (Japan); Goto, M.; Morita, S. [National Institute for Fusion Science, Toki 509-5292 (Japan)] [National Institute for Fusion Science, Toki 509-5292 (Japan)

    2014-02-15T23:59:59.000Z

    We report development of a high dynamic range spectroscopic system comprising a spectrometer with 30% throughput and a camera with a low-noise fast-readout complementary metal-oxide semiconductor sensor. The system achieves a 10{sup 6} dynamic range (?20 bit resolution) and an instrumental function approximated by a Voigt profile with Gauss and Lorentz widths of 31 and 0.31 pm, respectively, for 656 nm light. The application of the system for line profile observations of the Balmer-? emissions from high temperature plasmas generated in the Large Helical Device is also presented. In the observed line profiles, emissions are detected in far wings more than 1.0 nm away from the line center, equivalent to neutral hydrogen atom kinetic energies above 1 keV. We evaluate atom density distributions in the core plasma by analyzing the line profiles.

  19. Diagnosing collisions of magnetized, high energy density plasma flows using a combination of collective Thomson scattering, Faraday rotation, and interferometry (invited)

    SciTech Connect (OSTI)

    Swadling, G. F., E-mail: swadling@imperial.ac.uk; Lebedev, S. V.; Hall, G. N.; Patankar, S.; Stewart, N. H.; Smith, R. A.; Burdiak, G. C.; Grouchy, P. de; Skidmore, J.; Suttle, L.; Suzuki-Vidal, F.; Bland, S. N.; Kwek, K. H.; Pickworth, L.; Bennett, M.; Hare, J. D. [Plasma Physics Group, Imperial College, London SW6 7LZ (United Kingdom); Harvey-Thompson, A. J. [Sandia National Laboratory, Albuquerque, New Mexico 87185-1193 (United States); Rozmus, W. [Department of Physics, University of Alberta, Edmonton, Alberta T6G 2J1 (Canada); Yuan, J. [Key Laboratory of Pulsed Power, Institute of Fluid Physics, CAE, Mianyang 621900 (China)

    2014-11-15T23:59:59.000Z

    A suite of laser based diagnostics is used to study interactions of magnetised, supersonic, radiatively cooled plasma flows produced using the Magpie pulse power generator (1.4 MA, 240 ns rise time). Collective optical Thomson scattering measures the time-resolved local flow velocity and temperature across 7–14 spatial positions. The scattering spectrum is recorded from multiple directions, allowing more accurate reconstruction of the flow velocity vectors. The areal electron density is measured using 2D interferometry; optimisation and analysis are discussed. The Faraday rotation diagnostic, operating at 1053 nm, measures the magnetic field distribution in the plasma. Measurements obtained simultaneously by these diagnostics are used to constrain analysis, increasing the accuracy of interpretation.

  20. Fusion Energy Sciences

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    from discovery plasma science to high-power, long-pulse, and foundational burning plasma research. Current major collaborations include: divertor and edge plasma diagnostics on...

  1. IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 39, NO. 11, NOVEMBER 2011 3103 Helicon Plasma Discharge in a Toroidal

    E-Print Network [OSTI]

    Ji, Hantao

    superconducting tokamak (EAST) is the important part of the fusion development stratagem of China, which demands Program under Grants 2010GB106000 and 2010GB106009, by the National Natural Science Foundation of China 215006, China, and also with the Key Laboratory of Thin Films of Jiangsu, Soochow Univer- sity, Soochow

  2. Far-from-equilibrium dynamics of a strongly coupled non-Abelian plasma with non-zero charge density or external magnetic field

    E-Print Network [OSTI]

    Fuini, John F

    2015-01-01T23:59:59.000Z

    Using holography, we study the evolution of a spatially homogeneous, far from equilibrium, strongly coupled N=4 supersymmetric Yang-Mills plasma with a non-zero charge density or a background magnetic field. This gauge theory problem corresponds, in the dual gravity description, to an initial value problem in Einstein-Maxwell theory with homogeneous but anisotropic initial conditions. We explore the dependence of the equilibration process on different aspects of the initial departure from equilibrium and, while controlling for these dependencies, examine how the equilibration dynamics are affected by the presence of a non-vanishing charge density or an external magnetic field. The equilibration dynamics are remarkably insensitive to the addition of even large chemical potentials or magnetic fields; the equilibration time is set primarily by the form of the initial departure from equilibrium. For initial deviations from equilibrium which are well localized in scale, we formulate a simple model for equilibratio...

  3. Far-from-equilibrium dynamics of a strongly coupled non-Abelian plasma with non-zero charge density or external magnetic field

    E-Print Network [OSTI]

    John F. Fuini III; Laurence G. Yaffe

    2015-03-24T23:59:59.000Z

    Using holography, we study the evolution of a spatially homogeneous, far from equilibrium, strongly coupled N=4 supersymmetric Yang-Mills plasma with a non-zero charge density or a background magnetic field. This gauge theory problem corresponds, in the dual gravity description, to an initial value problem in Einstein-Maxwell theory with homogeneous but anisotropic initial conditions. We explore the dependence of the equilibration process on different aspects of the initial departure from equilibrium and, while controlling for these dependencies, examine how the equilibration dynamics are affected by the presence of a non-vanishing charge density or an external magnetic field. The equilibration dynamics are remarkably insensitive to the addition of even large chemical potentials or magnetic fields; the equilibration time is set primarily by the form of the initial departure from equilibrium. For initial deviations from equilibrium which are well localized in scale, we formulate a simple model for equilibration times which agrees quite well with our results.

  4. Plasma Wakefield Acceleration and FACET - Facilities for Accelerator Science and Experimental Test Beams at SLAC

    ScienceCinema (OSTI)

    Andrei Seryi

    2010-01-08T23:59:59.000Z

    Plasma wakefield acceleration is one of the most promising approaches to advancing accelerator technology. This approach offers a potential 1,000-fold or more increase in acceleration over a given distance, compared to existing accelerators.  FACET, enabled by the Recovery Act funds, will study plasma acceleration, using short, intense pulses of electrons and positrons. In this lecture, the physics of plasma acceleration and features of FACET will be presented.  

  5. On the program, vision, and budget for the fusion and plasma sciences

    E-Print Network [OSTI]

    relevant to clean energy with near-term payoff. With this as backdrop, the Administration affirms a strong Director, Office of Science For Fusion Energy Sciences U.S. Department of Energy Presented to the Fusion Energy Sciences Advisory Committee February 28, 2012 #12;The science at the heart of fusion energy is far

  6. Estimation of the electron density and radiative energy losses in a calcium plasma source based on an electron cyclotron resonance discharge

    SciTech Connect (OSTI)

    Potanin, E. P., E-mail: potanin@imp.kiae.ru; Ustinov, A. L. [National Research Centre Kurchatov Institute (Russian Federation)

    2013-06-15T23:59:59.000Z

    The parameters of a calcium plasma source based on an electron cyclotron resonance (ECR) discharge were calculated. The analysis was performed as applied to an ion cyclotron resonance system designed for separation of calcium isotopes. The plasma electrons in the source were heated by gyrotron microwave radiation in the zone of the inhomogeneous magnetic field. It was assumed that, in such a combined trap, the energy of the extraordinary microwave propagating from the high-field side was initially transferred to a small group of resonance electrons. As a result, two electron components with different transverse temperatures-the hot resonance component and the cold nonresonance component-were created in the plasma. The longitudinal temperatures of both components were assumed to be equal. The entire discharge space was divided into a narrow ECR zone, where resonance electrons acquired transverse energy, and the region of the discharge itself, where the gas was ionized. The transverse energy of resonance electrons was calculated by solving the equations for electron motion in an inhomogeneous magnetic field. Using the law of energy conservation and the balance condition for the number of hot electrons entering the discharge zone and cooled due to ionization and elastic collisions, the density of hot electrons was estimated and the dependence of the longitudinal temperature T{sub e Parallel-To} of the main (cold) electron component on the energy fraction {beta} lost for radiation was obtained.

  7. INSTITUTE OF PHYSICS PUBLISHING PLASMA SOURCES SCIENCE AND TECHNOLOGY Plasma Sources Sci. Technol. 15 (2006) 858864 doi:10.1088/0963-0252/15/4/032

    E-Print Network [OSTI]

    Greifswald, Ernst-Moritz-Arndt-Universität

    temperature in pulsed fluorocarbon rf plasmas O Gabriel1 , S Stepanov, M Pfafferott and J Meichsner Institute in fluorocarbon plasmas is essential for a fundamental understanding of plasma chemical processes and plasma fluorocarbon radio frequency plasmas were successfully applied, e.g. for contact hole etching [1]. Furthermore

  8. 2524 IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 42, NO. 10, OCTOBER 2014 Mitigation of Instabilities in a Z-Pinch Plasma by a

    E-Print Network [OSTI]

    Doron, Ramy

    the azimuthal and axial fields. Index Terms--Magnetic field effects, optical imaging, plasma pinch, plasma strengths at the same stage of compression, i.e., when the plasma column is imploded to a radius of 8 mm

  9. Atomic hydrogen densities in capacitively coupled very high-frequency plasmas in H{sub 2}: Effect of excitation frequency

    SciTech Connect (OSTI)

    Jolly, J.; Booth, J.-P. [Laboratoire de Physique et Technologie des Plasmas, Centre Nazionale de la Recherche Scientifique, Ecole Polytechnique, 91128 Palaiseau Cedex (France)

    2005-05-15T23:59:59.000Z

    Absolute hydrogen atom densities in pure hydrogen capacitive discharges were measured as a function of excitation frequency (13.56, 27.12, and 40.68 MHz), nominal electrical power, and gas pressure (between 0.1 and 1 Torr). Quantitative measurements were made using two-photon absorption laser-induced fluorescence (TALIF), put on an absolute scale by comparison with the TALIF signal from a known density of krypton gas, as proposed by Niemi, Schultz von Gathen, and Doebele [J. Phys. D 34, 2330 (2001)]. The H atom density increases with gas pressure and electrical power, and at a given power and pressure it increases significantly with excitation frequency. The latter can be attributed in part to increased electron density. However, time-resolved TALIF measurements in the afterglow showed that the H atom surface loss probabilities are not constant, becoming somewhat smaller when the sheath voltage is lowered, as is the case when the excitation frequency is increased, contributing to the increase in H density.

  10. THE MAGNETIC FIELD PILE-UP AND DENSITY DEPLETION IN THE MARTIAN MAGNETOSHEATH: A COMPARISON WITH THE PLASMA

    E-Print Network [OSTI]

    California at Berkeley, University of

    THE MAGNETIC FIELD PILE-UP AND DENSITY DEPLETION IN THE MARTIAN MAGNETOSHEATH: A COMPARISON Global Surveyor (MGS) and theWind spacecraft we show that the region of magnetic field pile of the terrestrial magnetopause when the magnetic field piles up against the obstacle and particles in the pile

  11. Absolute CF{sub 2} density and gas temperature measurements by absorption spectroscopy in dual-frequency capacitively coupled CF{sub 4}/Ar plasmas

    SciTech Connect (OSTI)

    Liu, Wen-Yao; Xu, Yong, E-mail: yongxu@dlut.edu.cn; Peng, Fei; Gong, Fa-Ping; Li, Xiao-Song; Zhu, Ai-Min [Key Laboratory of Materials Modification by Laser, Ion, and Electron Beams (Ministry of Education), School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China); Laboratory of Plasma Physical Chemistry, Dalian University of Technology, Dalian 116024 (China); Liu, Yong-Xin; Wang, You-Nian [Key Laboratory of Materials Modification by Laser, Ion, and Electron Beams (Ministry of Education), School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China)

    2014-10-15T23:59:59.000Z

    Broadband ultraviolet absorption spectroscopy has been used to determine the CF{sub 2} radical density in dual-frequency capacitively coupled CF{sub 4}/Ar plasmas, using the CF{sub 2} A{sup ~1}B{sub 1}?X{sup ~1}A{sub 1} system of absorption spectrum. The rotational temperature of ground state CF{sub 2} and excited state CF was also estimated by using A{sup ~1}B{sub 1}?X{sup ~1}A{sub 1} system and B{sup 2}??X{sup 2}? system, respectively. The translational gas temperature was deduced from the Doppler width of the Ar{sup *}({sup 3}P{sub 2}) and Ar{sup *}({sup 3}P{sub 0}) metastable atoms absorption line by using the tunable diode laser absorption spectroscopy. The rotational temperatures of the excited state CF are about 100?K higher than those of ground state CF{sub 2}, and about 200?K higher than the translational gas temperatures. The dependences of the radical CF{sub 2} density, electron density, electron temperature, rotational temperature, and gas temperature on the high frequency power and pressure have been analyzed. Furthermore, the production and loss mechanisms of CF{sub 2} radical and the gas heating mechanisms have also been discussed.

  12. U.S. Department of Energy's Plasma Science Center holds third...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    May 22, 2012 Tweet Widget Google Plus One Share on Facebook Jeff Walker, a University of West Virginia graduate student, discussed his poster on dusty plasmas with PPPL physicist...

  13. INSTITUTE OF PHYSICS PUBLISHING PLASMA SOURCES SCIENCE AND TECHNOLOGY Plasma Sources Sci. Technol. 12 (2003) 561575 PII: S0963-0252(03)66965-3

    E-Print Network [OSTI]

    Kushner, Mark

    2003-01-01T23:59:59.000Z

    , Department of Nuclear Engineering, 1406 W. Green St., Urbana, IL 61801, USA 2 Plasma Research Laboratory

  14. Atomic data of tungsten for current and future uses in fusion and plasma science

    SciTech Connect (OSTI)

    Clementson, J.; Beiersdorfer, P. [Physics Division, Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, CA 94551 (United States); Lennartsson, T. [Lund Observatory, Lund University, P.O. Box 43, SE-221 00 Lund (Sweden)

    2013-04-19T23:59:59.000Z

    Atomic physics has played an important role throughout the history of experimental plasma physics. For example, accurate knowledge of atomic properties has been crucial for understanding the plasma energy balance and for diagnostic development. With the shift in magnetic fusion research toward high-temperature burning plasmas like those expected to be produced in the ITER tokamak, the atomic physics of tungsten has become important. Tungsten will be a constituent of ITER plasmas because of its use as a plasma-facing material able to withstand high heat loads with lower tritium retention than other possible materials. Already, ITER diagnostics are being developed based on using tungsten radiation. In particular, the ITER Core Imaging X-ray Spectrometer (CIXS), which is designed to measure the core ion temperature and bulk plasma motion, is being based on the x-ray emission of neonlike tungsten ions (W{sup 64+}). In addition, tungsten emission will at ITER be measured by extreme ultraviolet (EUV) and optical spectrometers to determine its concentration in the plasma and to assess power loss and tungsten sputtering rates. On present-day tokamaks tungsten measurements are therefore being performed in preparation of ITER. Tungsten has very complex spectra and most are still unknown. The WOLFRAM project at Livermore aims to produce data for tungsten in various spectral bands: Lshell x-ray emission for CIXS development, soft x-ray and EUV M- and N-shell tungsten emission for understanding the edge radiation from ITER plasmas as well as from contemporary tokamaks, and O-shell emission for developing spectral diagnostics of the ITER divertor.

  15. Effect of Inert Gas Additive Species on Cl(2) High Density Plasma Etching of Compound Semiconductors: Part 1. GaAs and GaSb

    SciTech Connect (OSTI)

    Abernathy, C.R.; Cho, H.; Hahn, Y.B.; Hays, D.C.; Jung, K.B.; Pearton, S.J.; Shul, R.J.

    1998-12-23T23:59:59.000Z

    The role of the inert gas additive (He, Ar, Xe) to C12 Inductively Coupled Plasmas for dry etching of GaAs and GaSb was examined through the effect on etch rate, surface roughness and near-surface stoichiometry. The etch rates for both materials go through a maximum with Clz 0/0 in each type of discharge (C12/'He, C12/Ar, C12/Xc), reflecting the need to have efficient ion-assisted resorption of the etch products. Etch yields initially increase strongly with source power as the chlorine neutral density increases, but decrease again at high powers as the etching becomes reactant-limited. The etched surfaces are generally smoother with Ax or Xe addition, and maintain their stoichiometry.

  16. Computational Science Technical Note CSTN-172 Plasma Visualization in Parallel using Particle Systems on Graphical Processing

    E-Print Network [OSTI]

    Hawick, Ken

    as particle systems that emit light are important in many interesting components of games, computer animated = {April}, publisher = {WorldComp}, institution = {Computer Science, Massey University, Auckland, New Ken Hawick, Computer Science, Massey University, Albany, North Shore 102-904, Auckland, New Zealand

  17. Issues in "Burning Plasma Science" S. J. Zweben, D. S. Darrow

    E-Print Network [OSTI]

    development issues => big issue: local burn control in an AT · Our conclusions · Alternate path #12;Burning, not fusion energy development (i.e. reactor-relevance) General issues: What are the interesting plasma a viable fusion reactor (or, should it be)? #12;What are Fusion Energy Development Issues Which Could

  18. Plasma Sources Science and Technology Plasma Sources Sci. Technol. 23 (2014) 044005 (6pp) doi:10.1088/0963-0252/23/4/044005

    E-Print Network [OSTI]

    .1088/0963-0252/23/4/044005 Cross-field plasma lens for focusing of the Hall thruster plume Martin E Griswold, Yevgeny Raitses as a means to focus the thruster plume. In the PL, the plasma is nearly collisionless, with non from its ionization and acceleration using an external plasma lens (PL) to focus the beam after

  19. Stark broadening for diagnostics of the electron density in non-equilibrium plasma utilizing isotope hydrogen alpha lines

    SciTech Connect (OSTI)

    Yang, Lin [Institute of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000 (China); Institute of Electronic Engineering, China Academy of Engineering Physics, Mianyang 621900 (China); Tan, Xiaohua; Wan, Xiang; Chen, Lei; Jin, Dazhi; Qian, Muyang [Institute of Electronic Engineering, China Academy of Engineering Physics, Mianyang 621900 (China); Li, Gongping, E-mail: ligp@lzu.edu.cn [Institute of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000 (China)

    2014-04-28T23:59:59.000Z

    Two Stark broadening parameters including FWHM (full width at half maximum) and FWHA (full width at half area) of isotope hydrogen alpha lines are simultaneously introduced to determine the electron density of a pulsed vacuum arc jet. To estimate the gas temperature, the rotational temperature of the C{sub 2} Swan system is fit to 2500?±?100?K. A modified Boltzmann-plot method with b{sub i}-factor is introduced to determine the modified electron temperature. The comparison between results of atomic and ionic lines indicates the jet is in partial local thermodynamic equilibrium and the electron temperature is close to 13?000?±?400?K. Based on the computational results of Gig-Card calculation, a simple and precise interpolation algorithm for the discrete-points tables can be constructed to obtain the traditional n{sub e}-T{sub e} diagnostic maps of two Stark broadening parameters. The results from FWHA formula by the direct use of FWHM?=?FWHA and these from the diagnostic map are different. It can be attributed to the imprecise FWHA formula form and the deviation between FWHM and FWHA. The variation of the reduced mass pair due to the non-equilibrium effect contributes to the difference of the results derived from two hydrogen isotope alpha lines. Based on the Stark broadening analysis in this work, a corrected method is set up to determine n{sub e} of (1.10?±?0.08)?×?10{sup 21}?m{sup ?3}, the reference reduced mass ?{sub 0} pair of (3.30?±?0.82 and 1.65?±?0.41), and the ion kinetic temperature of 7900?±?1800?K.

  20. The Heavy Ion Fusion Science Virtual National Laboratory Recent advances in ion-beam-driven high energy density

    E-Print Network [OSTI]

    Laboratories under Contract Numbers DE-AC02-05CH1123 and W-7405-Eng-48, and by the Princeton Plasma Physics

  1. Physical Sciences 2007 Science & Technology Highlights

    SciTech Connect (OSTI)

    Hazi, A U

    2008-04-07T23:59:59.000Z

    The Physical Sciences Directorate applies frontier physics and technology to grand challenges in national security. Our highly integrated and multidisciplinary research program involves collaborations throughout Lawrence Livermore National Laboratory, the National Nuclear Security Administration, the Department of Energy, and with academic and industrial partners. The Directorate has a budget of approximately $150 million, and a staff of approximately 350 employees. Our scientists provide expertise in condensed matter and high-pressure physics, plasma physics, high-energy-density science, fusion energy science and technology, nuclear and particle physics, accelerator physics, radiation detection, optical science, biotechnology, and astrophysics. This document highlights the outstanding research and development activities in the Physical Sciences Directorate that made news in 2007. It also summarizes the awards and recognition received by members of the Directorate in 2007.

  2. Results from the Levitated Dipole Experiment MIT Plasma Science and Fusion Center

    E-Print Network [OSTI]

    lead naturally to breadth in science and technology · Example: Confinement in the field of a levitated dipole · Unique physics illuminated by closed field line systems · Unique technology challenges is centrally peaked with n ~ 1/V ~ R-4 · Farley et al. (1970): Turbulence causes strong inward particle pinch

  3. Princeton Plasma Physics Laboratory | U.S. DOE Office of Science (SC)

    Office of Science (SC) Website

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over OurTheBrookhaven National LaboratoryJeffreyMs.Princeton Plasma Physics Laboratory

  4. Fusion through the eyes of a veteran science journalist | Princeton Plasma

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville Power AdministrationField8,Dist.Newof EnergyFunding Opportunity fromFusion LinksPlasma

  5. Effects of magnetic flux density and substrate bias voltage on Ni films prepared on a flexible substrate material using unbalanced magnetron sputtering assisted by inductively coupled plasma

    SciTech Connect (OSTI)

    Koda, Tatsunori [Graduate School of Science and Technology, Hiroshima Institute of Technology, 2-1-1, Miyake, Saeki-ku, Hiroshima 7315193 (Japan); Toyota, Hiroshi, E-mail: h.toyota.za@it-hiroshima.ac.jp [Department of Electronics and Computer Engineering, Hiroshima Institute of Technology, 2-1-1, Miyake, Saeki-ku, Hiroshima 7315193 (Japan)

    2014-03-15T23:59:59.000Z

    The authors fabricated Ni films on a flexible substrate material using unbalanced magnetron sputtering assisted by inductively coupled plasma. The effects of magnetic flux density B{sub C} and substrate DC bias voltage V{sub S} on the Ni film structures were investigated. For V{sub S}?=??40?V, the average surface grain size D{sub G} measured by atomic force microscopy for B{sub C}?=?0, 3, and 5?mT was 88.2, 95.4, and 104.4?nm, respectively. In addition, D{sub G} increased with V{sub S}. From x-ray diffraction measurements, the (111) and (200) peaks were clearly visible for the fabricated Ni films. The ratio of the integrated intensities of I(111)/I(200) increased with V{sub S}. For V{sub S}?=??40?V and B{sub C}?=?3?mT, a film resistivity ? of 8.96?×?10{sup ?6} ? cm was observed, which is close to the Ni bulk value of 6.84?×?10{sup ?6} ? cm. From these results, the authors determined that the structure of the fabricated Ni films on the flexible substrate material was affected by the values of B{sub C} and V{sub S}.

  6. IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 39, NO. 4, APRIL 2011 1007 Inertial Confinement Fusion Using

    E-Print Network [OSTI]

    into the compressing target. Integrated FI experiments have begun on the OMEGA/OMEGA EP laser system. Index Terms compression of a solid deuterium­tritium (DT)-layered target on a low adiabat (defined as the ratio have demonstrated near-design compression with an areal density R 290 mg/cm2 at Vimp = 3.1 × 107 cm

  7. atmospheric plasma sources: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    in active plasma region and plasma parameters (electron density and electron distribution function) are determined. Concentrations of oxygen atoms and ozone in the plasma...

  8. Laser Plasma Particle Accelerators: Large Fields for Smaller Facility Sources

    E-Print Network [OSTI]

    Geddes, Cameron G.R.

    2010-01-01T23:59:59.000Z

    of high- gradient, laser plasma particle accelerators.accelerators that use laser-driven plasma waves. Theseleft) showing the laser (red), plasma wake density (purple-

  9. INSTITUTE OF PHYSICS PUBLISHING PLASMA SOURCES SCIENCE AND TECHNOLOGY Plasma Sources Sci. Technol. 16 (2007) 9096 doi:10.1088/0963-0252/16/1/012

    E-Print Network [OSTI]

    Economou, Demetre J.

    2007-01-01T23:59:59.000Z

    -dimensional simulation of the plasma reactor was coupled with a two-dimensional simulation of the sheath region overIEDisdeterminedbythedifferenceinpotentialbetweenthe plasma and the substrate, as well as ion collisions with the background neutral gas. For radio frequency were then neutralized to become fast neutrals in neutral beam applications [12,13]. In all

  10. Computational accelerator science needs towards laser-plasma accelerators for future colliders

    E-Print Network [OSTI]

    Geddes, C G R; Schroeder, C B; Esarey, E; Leemans, W P

    2013-01-01T23:59:59.000Z

    Laser plasma accelerators have the potential to reduce the size of future linacs for high energy physics by more than an order of magnitude, due to their high gradient. Research is in progress at current facilities, including the BELLA PetaWatt laser at LBNL, towards high quality 10 GeV beams and staging of multiple modules, as well as control of injection and beam quality. The path towards high-energy physics applications will likely involve hundreds of such stages, with beam transport, conditioning and focusing. Current research focuses on addressing physics and R&D challenges required for a detailed conceptual design of a future collider. Here, the tools used to model these accelerators and their resource requirements are summarized, both for current work and to support R&D addressing issues related to collider concepts.

  11. High Energy Density Laboratory Plasmas

    E-Print Network [OSTI]

    faciliBes 1st users of MECI in FY13 Recognize common interests NNSA/FES Compliment NNSA investments Stability ­ investments in HEDLP: people, departments

  12. MIT Plasma Science & Fusion Center: research>alcator>

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOnItem NotEnergy, science,SpeedingWu,IntelligenceYou are hereNews item$alt TrinityPhysics

  13. MIT Plasma Science & Fusion Center: research, alcator, publications & news,

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC)Integrated Codes |IsLove Your Home and It'll Love You Back LoveM odresearch highlights

  14. MIT Plasma Science & Fusion Center: research> alcator>tokamak data &

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC)Integrated Codes |IsLove Your Home and It'll Love You Back LoveMinfo, workreal-time

  15. MIT Plasma Science & Fusion Center: research>alcator>Conference Room

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC)Integrated Codes |IsLove Your Home and It'll Love You Back LoveMinfo,

  16. MIT Plasma Science & Fusion Center: research>alcator>contact

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC)Integrated Codes |IsLove Your Home and It'll Love You Back LoveMinfo,Facility

  17. MIT Plasma Science & Fusion Center: research>alcator>facility info

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC)Integrated Codes |IsLove Your Home and It'll Love You Back LoveMinfo,FacilityRemote

  18. MIT Plasma Science & Fusion Center: research>alcator>facility info

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC)Integrated Codes |IsLove Your Home and It'll Love You Back LoveMinfo,FacilityRemote

  19. MIT Plasma Science & Fusion Center: research>alcator>information

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC)Integrated Codes |IsLove Your Home and It'll Love You Back

  20. MIT Plasma Science & Fusion Center: research>alcator>introduction

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC)Integrated Codes |IsLove Your Home and It'll Love You BackTechnology & Engineering

  1. MIT Plasma Science & Fusion Center: research>alcator>introduction

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC)Integrated Codes |IsLove Your Home and It'll Love You BackTechnology &

  2. MIT Plasma Science & Fusion Center: research>alcator>publications &

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC)Integrated Codes |IsLove Your Home and It'll Love You BackTechnology

  3. MIT Plasma Science & Fusion Center: research>alcator>research program

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC)Integrated Codes |IsLove Your Home and It'll Love You BackTechnologyinformation>

  4. MIT Plasma Science & Fusion Center:<research<alcator<publications &

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC)Integrated Codes |IsLove Your Home and It'll Love You

  5. MIT Plasma Science & Fusion Center: research, alcator, pubs, CMod_2003.html

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHigh SchoolIn12electron 9November 6, Inapril apsaps quebecEnergy- Density

  6. Thermionic energy conversion plasmas

    SciTech Connect (OSTI)

    Rasor, N.S. (Rasor Associates, Inc., Sunnyvale, CA (United States))

    1991-12-01T23:59:59.000Z

    In this paper the history, application options, and ideal basic performance of the thermionic energy converter are outlined. The basic plasma types associated with various modes of converter operation are described, with emphasis on identification and semi-quantitative characterization of the dominant physical processes and utility of each plasma type. The frontier plasma science issues in thermionic converter applications are briefly summarized.

  7. 1014 IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 36, NO. 4, AUGUST 2008 Dust-Cloud Dynamics in a Complex

    E-Print Network [OSTI]

    Boyer, Edmond

    is proposed. Index Terms--Charge, dust cloud, dusty plasma. ACOMPLEX (dusty) plasma is a partially ionized gas research program (FAST) under Contract FR060169. L. Couëdel is with the School of Physics, The University of the plasma are lost by diffusion to the walls of the reactor and by recombination on the dust

  8. A NATIONAL COLLABORATORY TO ADVANCE THE SCIENCE OF HIGH TEMPERATURE PLASMA PHYSICS FOR MAGNETIC FUSION

    SciTech Connect (OSTI)

    Allen R. Sanderson; Christopher R. Johnson

    2006-08-01T23:59:59.000Z

    This report summarizes the work of the University of Utah, which was a member of the National Fusion Collaboratory (NFC) Project funded by the United States Department of Energy (DOE) under the Scientific Discovery through Advanced Computing Program (SciDAC) to develop a persistent infrastructure to enable scientific collaboration for magnetic fusion research. A five year project that was initiated in 2001, it the NFC built on the past collaborative work performed within the U.S. fusion community and added the component of computer science research done with the USDOE Office of Science, Office of Advanced Scientific Computer Research. The project was itself a collaboration, itself uniting fusion scientists from General Atomics, MIT, and PPPL and computer scientists from ANL, LBNL, and Princeton University, and the University of Utah to form a coordinated team. The group leveraged existing computer science technology where possible and extended or created new capabilities where required. The complete finial report is attached as an addendum. The In the collaboration, the primary technical responsibility of the University of Utah in the collaboration was to develop and deploy an advanced scientific visualization service. To achieve this goal, the SCIRun Problem Solving Environment (PSE) is used on FusionGrid for an advanced scientific visualization service. SCIRun is open source software that gives the user the ability to create complex 3D visualizations and 2D graphics. This capability allows for the exploration of complex simulation results and the comparison of simulation and experimental data. SCIRun on FusionGrid gives the scientist a no-license-cost visualization capability that rivals present day commercial visualization packages. To accelerate the usage of SCIRun within the fusion community, a stand-alone application built on top of SCIRun was developed and deployed. This application, FusionViewer, allows users who are unfamiliar with SCIRun to quickly create visualizations and perform analysis of their simulation data from either the MDSplus data storage environment or from locally stored HDF5 files. More advanced tools for visualization and analysis also were created in collaboration with the SciDAC Center for Extended MHD Modeling. Versions of SCIRun with the FusionViewer have been made available to fusion scientists on the Mac OS X, Linux, and other Unix based platforms and have been downloaded 1163 times. SCIRun has been used with NIMROD, M3D, BOUT fusion simulation data as well as simulation data from other SciDAC application areas (e.g., Astrophysics). The subsequent visualization results - including animations - have been incorporated into invited talks at multiple APS/DPP meetings as well as peer reviewed journal articles. As an example, SCIRun was used for the visualization and analysis of a NIMROD simulation of a disruption that occurred in a DIII-D experiment. The resulting animations and stills were presented as part of invited talks at APS/DPP meetings and the SC04 conference in addition to being highlighted in the NIH/NSF Visualization Research Challenges Report. By achieving its technical goals, the University of Utah played a key role in the successful development of a persistent infrastructure to enable scientific collaboration for magnetic fusion research. Many of the visualization tools developed as part of the NFC continue to be used by Fusion and other SciDAC application scientists and are currently being supported and expanded through follow-on up on SciDAC projects (Visualization and Analytics Center for Enabling Technology, and the Visualization and Analysis in Support of Fusion SAP).

  9. Experimental investigations of electron density and ion energy distributions in dual-frequency capacitively coupled plasmas for Ar/CF{sub 4} and Ar/O{sub 2}/CF{sub 4} discharges

    SciTech Connect (OSTI)

    Liu, Jia; Liu, Yong-Xin; Gao, Fei; Wang, You-Nian, E-mail: ynwang@dlut.edu.cn [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China); Bi, Zhen-Hua [School of Physics and Materials Engineering, Dalian Nationalities University, Dalian 116600 (China)

    2014-01-07T23:59:59.000Z

    The electron density and ion energy distribution (IED) are investigated in low-pressure dual-frequency capacitively coupled Ar/CF{sub 4} (90%/10%) and Ar/O{sub 2}/CF{sub 4} (80%/10%/10%) plasmas. The relations between controllable parameters, such as high-frequency (HF) power, low-frequency (LF) power and gas pressure, and plasma parameters, such as electron density and IEDs, are studied in detail by utilizing a floating hairpin probe and an energy resolved quadrupole mass spectrometer, respectively. In our experiment, the electron density is mainly determined by the HF power and slightly influenced by the LF power. With increasing gas pressure, the electron density first goes up rapidly to a maximum value and then decreases at various HF and LF powers. The HF power also plays a considerable role in affecting the IEDs under certain conditions and the ion energy independently controlled by the LF source is discussed here. For clarity, some numerical results obtained from a two-dimensional fluid model are presented.

  10. Frontiers for Discovery in High Energy Density Physics

    SciTech Connect (OSTI)

    Davidson, R. C.; Katsouleas, T.; Arons, J.; Baring, M.; Deeney, C.; Di Mauro, L.; Ditmire, T.; Falcone, R.; Hammer, D.; Hill, W.; Jacak, B.; Joshi, C.; Lamb, F.; Lee, R.; Logan, B. G.; Melissinos, A.; Meyerhofer, D.; Mori, W.; Murnane, M.; Remington, B.; Rosner, R.; Schneider, D.; Silvera, I.; Stone, J.; Wilde, B.; Zajc. W.

    2004-07-20T23:59:59.000Z

    The report is intended to identify the compelling research opportunities of high intellectual value in high energy density physics. The opportunities for discovery include the broad scope of this highly interdisciplinary field that spans a wide range of physics areas including plasma physics, laser and particle beam physics, nuclear physics, astrophysics, atomic and molecular physics, materials science and condensed matter physics, intense radiation-matter interaction physics, fluid dynamics, and magnetohydrodynamics

  11. Final report for the NSF/DOE partnership in basic plasma science grant DE-FG02-06ER54906 '?Laser-driven collisionless shocks in the Large Plasma Device'?

    SciTech Connect (OSTI)

    Niemann, Christoph [UCLA, CA (United States); Gekelman, W. [UCLA, CA (United States); Winske, D. [LANL, NM (United States); Larsen, D. [LLNL, CA (United States)

    2012-12-14T23:59:59.000Z

    We have performed several thousand high-energy laser shots in the LAPD to investigate the dynamics of an exploding laser-produced plasma in a large ambient magneto-plasma. Debris-ions expanding at super-Alfvenic velocity (up to MA=1.5) expel the ambient magnetic field, creating a large (> 20 cm) diamagnetic cavity. We observed field compressions of up to B/B{sub 0} = 1.5 at the edge of the bubble, consistent with the MHD jump conditions, as well as localized electron heating at the edge of the bubble. Two-dimensional hybrid simulations reproduce these measurements well and show that the majority of the ambient ions are energized by the magnetic piston to super-Alfvenic speeds and swept outside the bubble volume. Nonlinear shear-Alfven waves ({delta}B/B{sub 0} > 25%) are radiated from the cavity with a coupling efficiency of 70% from magnetic energy in the bubble to the wave. While the data is consistent with a weak magneto-sonic shock, the experiments were severely limited by the low ambient plasma densities (10{sup 12} cm{sup -3}). 2D hybrid simulations indicate that future experiments with the new LAPD plasma source and densities in excess of 10{sup 13} cm{sup -3} will drive full-blown collisionless shocks with MA>10 over several c/wpi and shocked Larmor radii. In a separate experiment at the LANL Trident laser facility we have performed a proof-of-principle experiment at higher densities to demonstrate key elements of collisionless shocks in laser-produced magnetized plasmas with important implications to NIF. Simultaneously we have upgraded the UCLA glass-laser system by adding two large amplitude disk amplifiers from the NOVA laser and boost the on-target energy from 30 J to up to 1 kJ, making this one of the world’s largest university-scale laser systems. We now have the infrastructure in place to perform novel and unique high-impact experiments on collision-less shocks at the LAPD.

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

    E-Print Network [OSTI]

    Gurnett, Donald A.

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

  13. Princeton Plasma Physics Laboratory

    SciTech Connect (OSTI)

    Not Available

    1990-01-01T23:59:59.000Z

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

  14. JOURNAL OF MATERIALS SCIENCE LETTERS 21, 2002, 951 953 Plasma-polymerized thiophene films for corrosion protection

    E-Print Network [OSTI]

    Boo, Jin-Hyo

    on corrosion behavior, impedance (Z) measurements for the steel electrodes coated and uncoated with the filmsCl solution were examined by electrochemical measurements and wettability tests. Plasma polymerization acetone, isopropyl alcohol and distilled water, the substrates were in-situ pre-treated with Ar plasma

  15. Intense Magnetized Plasma-Wall Interaction

    SciTech Connect (OSTI)

    Bauer, Bruno S. [UNR] [UNR; Fuelling, Stephan [UNR] [UNR

    2013-11-30T23:59:59.000Z

    This research project studied wall-plasma interactions relevant to fusion science. Such interactions are a critical aspect of Magneto-Inertial Fusion (MIF) because flux compression by a pusher material, in particular the metal for the liner approach to MIF, involves strong eddy current heating on the surface of the pusher, and probably interactions and mixing of the pusher with the interior fuel during the time when fusion fuel is being burned. When the pusher material is a metal liner, high-energy-density conditions result in fascinating behavior. For example, "warm dense matter" is produced, for which material properties such as resistivity and opacity are not well known. In this project, the transformation into plasma of metal walls subjected to pulsed megagauss magnetic fields was studied with an experiment driven by the UNR 1 MA Zebra generator. The experiment was numerically simulated with using the MHRDR code. This simple, fundamental high-energy-density physics experiment, in a regime appropriate to MIF, has stimulated an important and fascinating comparison of numerical modeling codes and tables with experiment. In addition, we participated in developing the FRCHX experiment to compress a field-reversed-configuration (FRC) plasma with a liner, in collaboration with researchers from Air Force Research Laboratory and Los Alamos National Lab, and we helped develop diagnostics for the Plasma Liner Experiment (PLX) at LANL. Last, but not least, this project served to train students in high-energy-density physics.

  16. SCIENCE CHINA Technological Sciences

    E-Print Network [OSTI]

    Simons, Jack

    SCIENCE CHINA Technological Sciences © Science China Press and Springer-Verlag Berlin Heidelberg. Density-functional-theory formulation of classical and quantum Hooke's law. Sci China Tech Sci, 2014, 57- sider an equilibrium lattice without strain (=0), but elec- #12;Hu H, et al. Sci China Tech Sci April

  17. An in-situ accelerator-based diagnostic for plasma-material interactions science in magnetic fusion devices

    E-Print Network [OSTI]

    Hartwig, Zachary Seth

    2014-01-01T23:59:59.000Z

    Plasma-material interactions (PMI) in magnetic fusion devices such as fuel retention, material erosion and redeposition, and material mixing present significant scientific and engineering challenges, particularly for the ...

  18. The evolution of ion charge states in cathodic vacuum arc plasmas: a review

    SciTech Connect (OSTI)

    Anders, Andre

    2011-12-18T23:59:59.000Z

    Cathodic vacuum arc plasmas are known to contain multiply charged ions. 20 years after “Pressure Ionization: its role in metal vapour vacuum arc plasmas and ion sources” appeared in vol. 1 of Plasma Sources Science and Technology, it is a great opportunity to re-visit the issue of pressure ionization, a non-ideal plasma effect, and put it in perspective to the many other factors that influence observable charge state distributions, such as the role of the cathode material, the path in the density-temperature phase diagram, the “noise” in vacuum arc plasma as described by a fractal model approach, the effects of external magnetic fields and charge exchange collisions with neutrals. A much more complex image of the vacuum arc plasma emerges putting decades of experimentation and modeling in perspective.

  19. Fundamentals of Plasma Physics

    E-Print Network [OSTI]

    Callen, James D.

    of students (from physics, engineering physics, elec- trical engineering, nuclear engineering and other un;PREFACE Plasma physics is a relatively new branch of physics that became a mature science over the last). Thus, plasma physics has developed in large part as a branch of applied or engineering physics

  20. Nonlinear plasma waves excitation by intense ion beams in background plasma

    E-Print Network [OSTI]

    Kaganovich, Igor

    describe the plasma perturbations well.5 Here, we focus on the general case where the plasma density hasNonlinear plasma waves excitation by intense ion beams in background plasma Igor D. Kaganovich, Edward A. Startsev, and Ronald C. Davidson Plasma Physics Laboratory, Princeton University, Princeton

  1. agricultural knowledge science: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Sciences Agricultural Economics Marine industry studies Corporate social Materials Science Plasma Physics Toxicology Aquatic ecosystems 12;Engineering Biological...

  2. JOURNAL OF MATERIALS SCIENCE LETTERS 22, 2003, 945 947 Electrochemical reliability of plasma-polymerized cyclohexane films

    E-Print Network [OSTI]

    Boo, Jin-Hyo

    of the effect of cyclohexane films on corrosion behav- ior, impedance measurements for the copper electrodesCl solution open to air. Impedance measurements were performed in the frequency range between 100 kHz and 1 m and distilled water, the sub- strates were in-situ pre-treated with Ar plasma to give an oxygen-free surface

  3. Planetary and Space Science 55 (2007) 17721792 The Analyser of Space Plasmas and Energetic Atoms (ASPERA-4)

    E-Print Network [OSTI]

    California at Berkeley, University of

    , Finland i Finnish Meteorological Institute, Box 503, FIN-00101 Helsinki, Finland j Space Physics Research objective of the ASPERA-4 (Analyser of Space Plasmas and Energetic Atoms) experiment is to study the solar flux (0.1­60 keV) with no mass and energy resolution but relatively high angular resolution

  4. 718 IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 34, NO. 3, JUNE 2006 Nonlinear Effects and Anomalous Transport

    E-Print Network [OSTI]

    Kaganovich, Igor

    . The first is a spiral coil shaped like a stove-top heating element and placed on the dielectric top cover understanding this. The second type of antenna, however, is wound around the cylindrical sides of the vacuum use, the parameters can be adjusted to produce a completely uni- form plasma across the diameter

  5. 728 IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 34, NO. 3, JUNE 2006 The Electron Diffusion Coefficient in Energy

    E-Print Network [OSTI]

    Kaganovich, Igor

    Coefficient in Energy in Bounded Collisional Plasmas Lev D. Tsendin Abstract--The electron energies in typical, the momentum relaxation in collisions with neutrals is sig- nificantly faster than the energy relaxation due be de- scribed by a diffusion coefficient in energy . Both collisional and stochastic heating mechanisms

  6. An in situ accelerator-based diagnostic for plasma-material interactions science on magnetic fusion devices

    SciTech Connect (OSTI)

    Hartwig, Zachary S.; Barnard, Harold S.; Lanza, Richard C.; Sorbom, Brandon N.; Stahle, Peter W.; Whyte, Dennis G. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge Massachusetts 02139 (United States)] [Plasma Science and Fusion Center, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge Massachusetts 02139 (United States)

    2013-12-15T23:59:59.000Z

    This paper presents a novel particle accelerator-based diagnostic that nondestructively measures the evolution of material surface compositions inside magnetic fusion devices. The diagnostic's purpose is to contribute to an integrated understanding of plasma-material interactions in magnetic fusion, which is severely hindered by a dearth of in situ material surface diagnosis. The diagnostic aims to remotely generate isotopic concentration maps on a plasma shot-to-shot timescale that cover a large fraction of the plasma-facing surface inside of a magnetic fusion device without the need for vacuum breaks or physical access to the material surfaces. Our instrument uses a compact (?1 m), high-current (?1 milliamp) radio-frequency quadrupole accelerator to inject 0.9 MeV deuterons into the Alcator C-Mod tokamak at MIT. We control the tokamak magnetic fields – in between plasma shots – to steer the deuterons to material surfaces where the deuterons cause high-Q nuclear reactions with low-Z isotopes ?5 ?m into the material. The induced neutrons and gamma rays are measured with scintillation detectors; energy spectra analysis provides quantitative reconstruction of surface compositions. An overview of the diagnostic technique, known as accelerator-based in situ materials surveillance (AIMS), and the first AIMS diagnostic on the Alcator C-Mod tokamak is given. Experimental validation is shown to demonstrate that an optimized deuteron beam is injected into the tokamak, that low-Z isotopes such as deuterium and boron can be quantified on the material surfaces, and that magnetic steering provides access to different measurement locations. The first AIMS analysis, which measures the relative change in deuterium at a single surface location at the end of the Alcator C-Mod FY2012 plasma campaign, is also presented.

  7. Perspective on the Role of Negative Ions and Ion-Ion Plasmas in Heavy Ion Fusion Science, Magnetic Fusion Energy, and Related Fields

    E-Print Network [OSTI]

    Kwan, J.W.

    2008-01-01T23:59:59.000Z

    Fusion Science, Magnetic Fusion Energy, and Related Fieldsof Science, Office of Fusion Energy Sciences, of the U.S.Fusion Science, Magnetic Fusion Energy, and Related Fields

  8. 384 IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 32, NO. 2, APRIL 2004 Efficient Particle Simulation of a Virtual Cathode

    E-Print Network [OSTI]

    Krasny, Robert

    of a Virtual Cathode Using a Grid-Free Treecode Poisson Solver Andrew J. Christlieb, Robert Krasny, and John P by National Science Foundation under Grant DMS-9977371 and Grant DMS-0107187. A. J. Christlieb and R. Krasny

  9. PUBLISHED ONLINE: 17 NOVEMBER 2013 | DOI: 10.1038/NPHYS2795 A long-pulse high-confinement plasma

    E-Print Network [OSTI]

    Loss, Daniel

    , Chinese Academy of Sciences, Hefei 230031, China, 2Tri Alpha Energy, Inc., PO Box 7010, Rancho Santa energy source with an abundant fuel supply. One of the most promising approaches to harnessing fusion degrees Celsius) plasma state with sufficient density and energy confinement time. Significant progress

  10. Magnetoacoustic solitons in quantum plasma

    SciTech Connect (OSTI)

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

    2011-08-15T23:59:59.000Z

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

  11. Science

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's PossibleRadiationImplementingnpitcheResearch BriefsTenney, Office of Science Office of Science β

  12. Science

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's PossibleRadiationImplementingnpitcheResearch BriefsTenney, Office of Science Office of Science

  13. REPORT FROM THE PLANNING WORKSHOP FUSION ENERGY SCIENCES PROGRAM

    E-Print Network [OSTI]

    research recognizes the utility of plasma research to the nation's science and technology base beyond

  14. Development and Benchmarking of a Hybrid PIC Code For Dense Plasmas and Fast Ignition

    SciTech Connect (OSTI)

    Witherspoon, F. Douglas [HyperV Technologies Corp.; Welch, Dale R. [Voss Scientific, LLC; Thompson, John R. [FAR-TECH, Inc.; MacFarlane, Joeseph J. [Prism Computational Sciences Inc.; Phillips, Michael W. [Advanced Energy Systems, Inc.; Bruner, Nicki [Voss Scientific, LLC; Mostrom, Chris [Voss Scientific, LLC; Thoma, Carsten [Voss Scientific, LLC; Clark, R. E. [Voss Scientific, LLC; Bogatu, Nick [FAR-TECH, Inc.; Kim, Jin-Soo [FAR-TECH, Inc.; Galkin, Sergei [FAR-TECH, Inc.; Golovkin, Igor E. [Prism Computational Sciences, Inc.; Woodruff, P. R. [Prism Computational Sciences, Inc.; Wu, Linchun [HyperV Technologies Corp.; Messer, Sarah J. [HyperV Technologies Corp.

    2014-05-20T23:59:59.000Z

    Radiation processes play an important role in the study of both fast ignition and other inertial confinement schemes, such as plasma jet driven magneto-inertial fusion, both in their effect on energy balance, and in generating diagnostic signals. In the latter case, warm and hot dense matter may be produced by the convergence of a plasma shell formed by the merging of an assembly of high Mach number plasma jets. This innovative approach has the potential advantage of creating matter of high energy densities in voluminous amount compared with high power lasers or particle beams. An important application of this technology is as a plasma liner for the flux compression of magnetized plasma to create ultra-high magnetic fields and burning plasmas. HyperV Technologies Corp. has been developing plasma jet accelerator technology in both coaxial and linear railgun geometries to produce plasma jets of sufficient mass, density, and velocity to create such imploding plasma liners. An enabling tool for the development of this technology is the ability to model the plasma dynamics, not only in the accelerators themselves, but also in the resulting magnetized target plasma and within the merging/interacting plasma jets during transport to the target. Welch pioneered numerical modeling of such plasmas (including for fast ignition) using the LSP simulation code. Lsp is an electromagnetic, parallelized, plasma simulation code under development since 1995. It has a number of innovative features making it uniquely suitable for modeling high energy density plasmas including a hybrid fluid model for electrons that allows electrons in dense plasmas to be modeled with a kinetic or fluid treatment as appropriate. In addition to in-house use at Voss Scientific, several groups carrying out research in Fast Ignition (LLNL, SNL, UCSD, AWE (UK), and Imperial College (UK)) also use LSP. A collaborative team consisting of HyperV Technologies Corp., Voss Scientific LLC, FAR-TECH, Inc., Prism Computational Sciences, Inc. and Advanced Energy Systems Inc. joined efforts to develop new physics and numerical models for LSP in several key areas to enhance the ability of LSP to model high energy density plasmas (HEDP). This final report details those efforts. Areas addressed in this research effort include: adding radiation transport to LSP, first in 2D and then fully 3D, extending the EMHD model to 3D, implementing more advanced radiation and electrode plasma boundary conditions, and installing more efficient implicit numerical algorithms to speed complex 2-D and 3-D computations. The new capabilities allow modeling of the dominant processes in high energy density plasmas, and further assist the development and optimization of plasma jet accelerators, with particular attention to MHD instabilities and plasma/wall interaction (based on physical models for ion drag friction and ablation/erosion of the electrodes). In the first funding cycle we implemented a solver for the radiation diffusion equation. To solve this equation in 2-D, we used finite-differencing and applied the parallelized sparse-matrix solvers in the PETSc library (Argonne National Laboratory) to the resulting system of equations. A database of the necessary coefficients for materials of interest was assembled using the PROPACEOS and ATBASE codes from Prism. The model was benchmarked against Prism's 1-D radiation hydrodynamics code HELIOS, and against experimental data obtained from HyperV's separately funded plasma jet accelerator development program. Work in the second funding cycle focused on extending the radiation diffusion model to full 3-D, continued development of the EMHD model, optimizing the direct-implicit model to speed up calculations, add in multiply ionized atoms, and improved the way boundary conditions are handled in LSP. These new LSP capabilities were then used, along with analytic calculations and Mach2 runs, to investigate plasma jet merging, plasma detachment and transport, restrike and advanced jet accelerator design. In addition, a strong linkage to diagnostic measureme

  15. Review: engineering particles using the aerosol-through-plasma method

    SciTech Connect (OSTI)

    Phillips, Jonathan [Los Alamos National Laboratory; Luhrs, Claudia C [UNM; Richard, Monique [TEMA

    2009-01-01T23:59:59.000Z

    For decades, plasma processing of materials on the nanoscale has been an underlying enabling technology for many 'planar' technologies, particularly virtually every aspect of modern electronics from integrated-circuit fabrication with nanoscale elements to the newest generation of photovoltaics. However, it is only recent developments that suggest that plasma processing can be used to make 'particulate' structures of value in fields, including catalysis, drug delivery, imaging, higher energy density batteries, and other forms of energy storage. In this paper, the development of the science and technology of one class of plasma production of particulates, namely, aerosol-through-plasma (A-T-P), is reviewed. Various plasma systems, particularly RF and microwave, have been used to create nanoparticles of metals and ceramics, as well as supported metal catalysts. Gradually, the complexity of the nanoparticles, and concomitantly their potential value, has increased. First, unique two-layer particles were generated. These were postprocessed to create unique three-layer nanoscale particles. Also, the technique has been successfully employed to make other high-value materials, including carbon nanotubes, unsupported graphene, and spherical boron nitride. Some interesting plasma science has also emerged from efforts to characterize and map aerosol-containing plasmas. For example, it is clear that even a very low concentration of particles dramatically changes plasma characteristics. Some have also argued that the local-thermodynamic-equilibrium approach is inappropriate to these systems. Instead, it has been suggested that charged- and neutral-species models must be independently developed and allowed to 'interact' only in generation terms.

  16. Absolute intensity calibration of flat-field space-resolved extreme ultraviolet spectrometer using radial profiles of visible and extreme ultraviolet bremsstrahlung continuum emitted from high-density plasmas in Large Helical Device

    SciTech Connect (OSTI)

    Dong Chunfeng; Wang Erhui [Department of Fusion Science, Graduate University for Advanced Studies, Toki 509-5292, Gifu (Japan); Morita, Shigeru; Goto, Motoshi [Department of Fusion Science, Graduate University for Advanced Studies, Toki 509-5292, Gifu (Japan); National Institute for Fusion Science, Toki 509-5292, Gifu (Japan)

    2011-11-15T23:59:59.000Z

    A precise absolute intensity calibration of a flat-field space-resolved extreme ultraviolet (EUV) spectrometer working in wavelength range of 60-400 A is carried out using a new calibration technique based on radial profile measurement of the bremsstrahlung continuum in Large Helical Device. A peaked vertical profile of the EUV bremsstrahlung continuum has been successfully observed in high-density plasmas (n{sub e}{>=} 10{sup 14} cm{sup -3}) with hydrogen ice pellet injection. The absolute calibration can be done by comparing the EUV bremsstrahlung profile with the visible bremsstrahlung profile of which the absolute value has been already calibrated using a standard lamp. The line-integrated profile of measured visible bremsstrahlung continuum is firstly converted into the local emissivity profile by considering a magnetic surface distortion due to the plasma pressure, and the local emissivity profile of EUV bremsstrahlung is secondly calculated by taking into account the electron temperature profile and free-free gaunt factor. The line-integrated profile of the EUV bremsstrahlung continuum is finally calculated from the local emissivity profile in order to compare with measured EUV bremsstrahlung profile. The absolute intensity calibration can be done by comparing measured and calculated EUV bremsstrahlung profiles. The calibration factor is thus obtained as a function of wavelength with excellent accuracy. It is also found in the profile analysis that the grating reflectivity of EUV emissions is constant along the direction perpendicular to the wavelength dispersion. Uncertainties on the calibration factor determined with the present method are discussed including charge-coupled device operation modes.

  17. James W. Van Dam US Burning Plasma Organization

    E-Print Network [OSTI]

    focus: magnetically confined plasmas #12;Page 5 USBPO What is a "burning" plasma? · "Burning" plasmaJames W. Van Dam US Burning Plasma Organization US ITER Project Office Institute for Fusion Studies Plasmas -- A Tutorial -- Supported by Office of Science #12;Page 2 USBPO The next frontier · Understanding

  18. SciDAC Fusiongrid Project--A National Collaboratory to Advance the Science of High Temperature Plasma Physics for Magnetic Fusion

    SciTech Connect (OSTI)

    SCHISSEL, D.P.; ABLA, G.; BURRUSS, J.R.; FEIBUSH, E.; FREDIAN, T.W.; GOODE, M.M.; GREENWALD, M.J.; KEAHEY, K.; LEGGETT, T.; LI, K.; McCUNE, D.C.; PAPKA, M.E.; RANDERSON, L.; SANDERSON, A.; STILLERMAN, J.; THOMPSON, M.R.; URAM, T.; WALLACE, G.

    2006-08-31T23:59:59.000Z

    This report summarizes the work of the National Fusion Collaboratory (NFC) Project funded by the United States Department of Energy (DOE) under the Scientific Discovery through Advanced Computing Program (SciDAC) to develop a persistent infrastructure to enable scientific collaboration for magnetic fusion research. A five year project that was initiated in 2001, it built on the past collaborative work performed within the U.S. fusion community and added the component of computer science research done with the USDOE Office of Science, Office of Advanced Scientific Computer Research. The project was a collaboration itself uniting fusion scientists from General Atomics, MIT, and PPPL and computer scientists from ANL, LBNL, Princeton University, and the University of Utah to form a coordinated team. The group leveraged existing computer science technology where possible and extended or created new capabilities where required. Developing a reliable energy system that is economically and environmentally sustainable is the long-term goal of Fusion Energy Science (FES) research. In the U.S., FES experimental research is centered at three large facilities with a replacement value of over $1B. As these experiments have increased in size and complexity, there has been a concurrent growth in the number and importance of collaborations among large groups at the experimental sites and smaller groups located nationwide. Teaming with the experimental community is a theoretical and simulation community whose efforts range from applied analysis of experimental data to fundamental theory (e.g., realistic nonlinear 3D plasma models) that run on massively parallel computers. Looking toward the future, the large-scale experiments needed for FES research are staffed by correspondingly large, globally dispersed teams. The fusion program will be increasingly oriented toward the International Thermonuclear Experimental Reactor (ITER) where even now, a decade before operation begins, a large portion of national program efforts are organized around coordinated efforts to develop promising operational scenarios. Substantial efforts to develop integrated plasma modeling codes are also underway in the U.S., Europe and Japan. As a result of the highly collaborative nature of FES research, the community is facing new and unique challenges. While FES has a significant track record for developing and exploiting remote collaborations, with such large investments at stake, there is a clear need to improve the integration and reach of available tools. The NFC Project was initiated to address these challenges by creating and deploying collaborative software tools. The original objective of the NFC project was to develop and deploy a national FES 'Grid' (FusionGrid) that would be a system for secure sharing of computation, visualization, and data resources over the Internet. The goal of FusionGrid was to allow scientists at remote sites to participate as fully in experiments and computational activities as if they were working on site thereby creating a unified virtual organization of the geographically dispersed U.S. fusion community. The vision for FusionGrid was that experimental and simulation data, computer codes, analysis routines, visualization tools, and remote collaboration tools are to be thought of as network services. In this model, an application service provider (ASP) provides and maintains software resources as well as the necessary hardware resources. The project would create a robust, user-friendly collaborative software environment and make it available to the US FES community. This Grid's resources would be protected by a shared security infrastructure including strong authentication to identify users and authorization to allow stakeholders to control their own resources. In this environment, access to services is stressed rather than data or software portability.

  19. Boundary Plasma Issues in Burning Plasma Science

    E-Print Network [OSTI]

    · divertor plate and magnetic geometry buys factor ~ 100, i.e. qu ~ 0.5 GW m-2 steady-state, qu ~ 2.0 GW m-2 SOL u P~q P )n( ~ 9/5 SOL 9/7 P u #12;(1) Wide Dispersal of Power/(cont) ELMs · ELMs exhaust power

  20. Boundary Plasma Issues in Burning Plasma Science

    E-Print Network [OSTI]

    Pitcher, C. S.

    .e. qu ~ 0.5 GW m-2 steady-state, qu ~ 2.0 GW m-2 pulsed ···· c.f. ITER, qu ~ 1 to 2 GW m-2, C-Mod ~ 0 of Power/(cont) ELMs · ELMs exhaust power in short periods of time (

  1. Boundary Plasma Issues in Burning Plasma Science

    E-Print Network [OSTI]

    Pitcher, C. S.

    ···· divertor plate and magnetic geometry buys factor ~ 100, i.e. qu ~ 0.5 GW m-2 steady-state, qu ~ 2.0 GW m-2 experiments! P SOL u P~q P )n( ~ 9/5 SOL 9/7 P u #12;(1) Wide Dispersal of Power/(cont) ELMs · ELMs exhaust

  2. Basic Plasma Science | Princeton Plasma Physics Lab

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOnItem NotEnergy,ARMForms About BecomeTechnologiesVehicleAuthorAwardsarticleOfficeBasic

  3. Lithium plasma emitter for collisionless magnetized plasma experiment

    SciTech Connect (OSTI)

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

    2011-09-15T23:59:59.000Z

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

  4. Science

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of ScienceandMesa del Sol HomeFacebook Twitter Principalfuel cells" Find + AdvancedSignScience

  5. Science

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOnItemResearch > TheNuclearHomeland Science Stockpile Stewardship National Security

  6. 714 IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 38, NO. 4, APRIL 2010 Interaction of a CO2 Laser Pulse With Tin-Based

    E-Print Network [OSTI]

    Najmabadi, Farrokh

    Pulse With Tin-Based Plasma for an Extreme Ultraviolet Lithography Source Yezheng Tao, Mark S. Tillack

  7. Energy in density gradient

    E-Print Network [OSTI]

    Vranjes, J

    2015-01-01T23:59:59.000Z

    Inhomogeneous plasmas and fluids contain energy stored in inhomogeneity and they naturally tend to relax into lower energy states by developing instabilities or by diffusion. But the actual amount of energy in such inhomogeneities has remained unknown. In the present work the amount of energy stored in a density gradient is calculated for several specific density profiles in a cylindric configuration. This is of practical importance for drift wave instability in various plasmas, and in particular in its application in models dealing with the heating of solar corona because the instability is accompanied with stochastic heating, so the energy contained in inhomogeneity is effectively transformed into heat. It is shown that even for a rather moderate increase of the density at the axis in magnetic structures in the corona by a factor 1.5 or 3, the amount of excess energy per unit volume stored in such a density gradient becomes several orders of magnitude greater than the amount of total energy losses per unit ...

  8. Michigan Institute Science and

    E-Print Network [OSTI]

    Shyy, Wei

    . Kaita's present research interests focus on plasma-surface interactions and the use of liquid metalsMichigan Institute for Plasma Science and Engineering Seminar Up Against the Wall: Liquid Lithium for the Chamber Technology Challenge in Fusion Energy Dr. Robert Kaita Princeton Plasma Physics Laboratory 3:00 pm

  9. applications plasma rate-coefficients: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Websites Summary: Institute of Science, Rehovot 76100, Israel b Institute for Plasma Research, University of Maryland, College in plasmas have been developed, where the motion...

  10. Papers presented at the eleventh topical conference on high-temperature plasma diagnostics

    SciTech Connect (OSTI)

    NONE

    1996-12-31T23:59:59.000Z

    This report contains the following eleven papers presented at the conference: Neutral Beam Diagnostics for Alcator C-Mod; A Study for the Installation of the TEXT HIBP on DIII-D; Time-domain Triple-probe Measurement of Edge Plasma Turbulence on TEXT-U; A Langmuir/Mach Probe Array for Edge Plasma Turbulence and Flow; Determination of Field Line Location and Safety Factor in TEXT-U; Hybrid ECE Imaging Array System for TEXT-U; First Results from the Phase Contrast Imaging System on TEXT-U; A Fast Tokamak Plasma Flux and Electron Density Reconstruction Technique; Time-series Analysis of Nonstationary Plasma Fluctuations Using Wavelet Transforms; Quantitative Modeling of 3-D Camera Views for Tokamak Divertors; and Variable-frequency Complex Demodulation Technique for Extracting Amplitude and Phase Information. Selected papers are indexed separately for inclusion in the Energy Science and Technology Database.

  11. DENSITY LIMITS IN TOROIDAL PLASMAS MARTIN GREENWALD

    E-Print Network [OSTI]

    Greenwald, Martin

    ;ACKNOWLEDGEMENTS · All people who have worked in this area over the years · Note particularly people who power scaling) (Axon 1980) #12;SCALING REFINED BY INCLUSION OF DATA FROM SHAPED TOKAMAKS · Greenwald

  12. High-Energy-Density Plasmas, Fluids

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOnItem NotEnergy,ARMFormsGasReleaseSpeechesHallNot Logged3 HanfordHarry|

  13. Measurements of electron density profiles using an angular filter refractometer

    SciTech Connect (OSTI)

    Haberberger, D., E-mail: dhab@lle.rochester.edu; Ivancic, S.; Hu, S. X.; Boni, R.; Barczys, M.; Craxton, R. S.; Froula, D. H. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14636 (United States)] [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14636 (United States)

    2014-05-15T23:59:59.000Z

    A novel diagnostic technique, angular filter refractometry (AFR), has been developed to characterize high-density, long-scale-length plasmas relevant to high-energy-density physics experiments. AFR measures plasma densities up to 10{sup 21}?cm{sup ?3} with a 263-nm probe laser and is used to study the plasma expansion from CH foil and spherical targets that are irradiated with ?9?kJ of ultraviolet (351-nm) laser energy in a 2-ns pulse. The data elucidate the temporal evolution of the plasma profile for the CH planar targets and the dependence of the plasma profile on target radius for CH spheres.

  14. E-Print Network 3.0 - av accelerates plasma Sample Search Results

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    for Plasma in the Laboratory and Astrophysics Collection: Physics ; Plasma Physics and Fusion 5 Lower hybrid current drive at densities required for thermonuclear reactors R....

  15. Meter scale plasma source for plasma wakefield experiments

    SciTech Connect (OSTI)

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

    2012-12-21T23:59:59.000Z

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

  16. Integrating Experiment and Theory in Electrochemical Surface Science: Studies on the Molecular Adsorption on Noble-Metal Electrode Surfaces by Density Functional Theory, Electron Spectroscopy, and Electrochemistry

    E-Print Network [OSTI]

    Javier, Alnald Caintic

    2013-08-05T23:59:59.000Z

    Computational techniques based on density functional theory (DFT) and experimental methods based on electrochemistry (EC), electrochemical scanning tunneling microscopy (EC-STM), and high-resolution electron energy loss spectroscopy (HREELS) were...

  17. Plasma Simulation Program

    SciTech Connect (OSTI)

    Greenwald, Martin

    2011-10-04T23:59:59.000Z

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

  18. Plasma generating apparatus for large area plasma processing

    DOE Patents [OSTI]

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

    1991-07-16T23:59:59.000Z

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

  19. Plasma generating apparatus for large area plasma processing

    DOE Patents [OSTI]

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

    1991-01-01T23:59:59.000Z

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

  20. Neutral depletion and the helicon density limit

    SciTech Connect (OSTI)

    Magee, R. M.; Galante, M. E.; Carr, J. Jr.; Lusk, G.; McCarren, D. W.; Scime, E. E. [West Virginia University, Morgantown, West Virginia 26506 (United States)] [West Virginia University, Morgantown, West Virginia 26506 (United States)

    2013-12-15T23:59:59.000Z

    It is straightforward to create fully ionized plasmas with modest rf power in a helicon. It is difficult, however, to create plasmas with density >10{sup 20} m{sup ?3}, because neutral depletion leads to a lack of fuel. In order to address this density limit, we present fast (1 MHz), time-resolved measurements of the neutral density at and downstream from the rf antenna in krypton helicon plasmas. At the start of the discharge, the neutral density underneath the antenna is reduced to 1% of its initial value in 15 ?s. The ionization rate inferred from these data implies that the electron temperature near the antenna is much higher than the electron temperature measured downstream. Neutral density measurements made downstream from the antenna show much slower depletion, requiring 14 ms to decrease by a factor of 1/e. Furthermore, the downstream depletion appears to be due to neutral pumping rather than ionization.

  1. Control of focusing forces and emittances in plasma-based accelerators using near-hollow plasma channels

    SciTech Connect (OSTI)

    Schroeder, Carl; Esarey, Eric; Benedetti, Carlo; Leemans, Wim

    2013-08-06T23:59:59.000Z

    A near-hollow plasma channel, where the plasma density in the channel is much less than the plasma density in the walls, is proposed to provide independent control over the focusing and accelerating forces in a plasma accelerator. In this geometry the low density in the channel contributes to the focusing forces, while the accelerating fields are determined by the high density in the channel walls. The channel also provides guiding for intense laser pulses used for wakefield excitation. Both electron and positron beams can be accelerated in a nearly symmetric fashion. Near-hollow plasma channels can effectively mitigate emittance growth due to Coulomb scattering for high energy physics applications.

  2. Plasma diagnostic reflectometry

    SciTech Connect (OSTI)

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

    1996-02-26T23:59:59.000Z

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

  3. PLASMA SCIENCE ADVANCED COMPUTING INTITUTE

    E-Print Network [OSTI]

    , ... leading to ITER -- impact real decision-making in the large "scientific options space" -- harvest

  4. AlGaN UV LED and Photodiodes Radiation Hardness and Space Qualifications and Their Applications in Space Science and High Energy Density Physics

    SciTech Connect (OSTI)

    Sun, K. X.

    2011-05-31T23:59:59.000Z

    This presentation provides an overview of robust, radiation hard AlGaN optoelectronic devices and their applications in space exploration & high energy density physics. Particularly, deep UV LED and deep UV photodiodes are discussed with regard to their applications, radiation hardness and space qualification. AC charge management of UV LED satellite payload instruments, which were to be launched in late 2012, is covered.

  5. Fluorination mechanisms of Al{sub 2}O{sub 3} and Y{sub 2}O{sub 3} surfaces irradiated by high-density CF{sub 4}/O{sub 2} and SF{sub 6}/O{sub 2} plasmas

    SciTech Connect (OSTI)

    Miwa, Kazuhiro; Takada, Noriharu; Sasaki, Koichi [Department of Electrical Engineering and Computer Science, Nagoya University, Nagoya, 464-8603 (Japan); Plasma Nanotechnology Research Center, Nagoya University, Nagoya 464-8603 (Japan)

    2009-07-15T23:59:59.000Z

    Fluorination of Al{sub 2}O{sub 3} and Y{sub 2}O{sub 3} surfaces was investigated by irradiating high-density, helicon-wave CF{sub 4}/O{sub 2} and SF{sub 6}/O{sub 2} plasmas. The Al{sub 2}O{sub 3} surface bombarded by high-flux positive ions of the CF{sub 4}/O{sub 2} plasma was fluorinated significantly. On contrast, Y{sub 2}O{sub 3} was less fluorinated than Al{sub 2}O{sub 3} when they were irradiated by the same CF{sub 4}/O{sub 2} plasma. The analysis of the Al{sub 2}O{sub 3} surface irradiated by the CF{sub 4}/O{sub 2} plasma suggests that the fluorination is triggered by reactions between fluorocarbon deposit and Al-O bonding with the assistance of ion bombardment. On the other hand, irradiation of the SF{sub 6}/O{sub 2} plasma induced less significant fluorination on the Al{sub 2}O{sub 3} surface. This suggests a lower reaction probability between sulfur fluoride deposit and Al-O bonding. The difference in the fluorination of the Al{sub 2}O{sub 3} and Y{sub 2}O{sub 3} surfaces induced by the irradiations of the CF{sub 4}/O{sub 2} and SF{sub 6}/O{sub 2} plasmas is understood by comparing the bonding energies of C-O, S-O, Al-O, and Y-O.

  6. australian nuclear science: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Volume6No.5 Science Magazine of the australian national Chen, Ying 3 Nuclear Science & Engineering Plasma Physics and Fusion Websites Summary: Center Massachusetts Institute of...

  7. axisymmetric rotating plasmas: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    by E B? drift, giving rise to macroscopic parameters are as follows: the electron temperature is 10-20 eV, the plasma density 1010 cm-3 (hole plasma of a small loop of...

  8. Nonequilibrium lighting plasmas

    SciTech Connect (OSTI)

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

    1991-12-01T23:59:59.000Z

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

  9. advanced fuel science: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Plasma Physics Laboratory 15 Hindawi Publishing Corporation Advances in Materials Science and Engineering Energy Storage, Conversion and Utilization Websites Summary:...

  10. axisymmetric tokamak plasmas: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Robert G. Kleva and Parvez N. Guzdar Materials Science Websites Summary: for Plasma Research, University of Maryland, College Park, Maryland 20770 Received 9 June 1999;...

  11. ac plasma polymerisation: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Physics and Fusion Websites Summary: ons USBPO - Coordinates US burning plasma research, to advance scienfic understanding USBPO organizes the US Fusion Energy Science...

  12. ac plasma electrolytic: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Physics and Fusion Websites Summary: ons USBPO - Coordinates US burning plasma research, to advance scienfic understanding USBPO organizes the US Fusion Energy Science...

  13. ac plasma display: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Physics and Fusion Websites Summary: ons USBPO - Coordinates US burning plasma research, to advance scienfic understanding USBPO organizes the US Fusion Energy Science...

  14. ac plasma polymerization: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Physics and Fusion Websites Summary: ons USBPO - Coordinates US burning plasma research, to advance scienfic understanding USBPO organizes the US Fusion Energy Science...

  15. INTERACTION OF MUON BEAM WITH PLASMA DEVELOPED DURING IONIZATION COOLING

    SciTech Connect (OSTI)

    S. Ahmed, D. Kaplan, T. Roberts, L. Spentzouris, K. Beard

    2012-07-01T23:59:59.000Z

    Particle-in-cell simulations involving the interaction of muon beam (peak density 10{sup 18} m{sup 3}) with Li plasma (ionized medium) of density 10{sup 16}-10{sup 22} m{sup -3} have been performed. This study aimed to understand the effects of plasma on an incoming beam in order to explore scenario developed during the process of ionization cooling. The computer code takes into account the self-consistent electromagnetic effects of beam interacting with plasma. This study shows that the beam can pass through the plasma of densities four order of magnitude higher than its peak density. The low density plasmas are wiped out by the beam, however, the resonance is observed for densities of similar order. Study reveals the signature of plasma wakefield acceleration.

  16. Aerodynamic Focusing Of High-Density Aerosols

    SciTech Connect (OSTI)

    Ruiz, D. E.; Fisch, Nathaniel

    2014-02-24T23:59:59.000Z

    High-density micron-sized particle aerosols might form the basis for a number of applications in which a material target with a particular shape might be quickly ionized to form a cylindrical or sheet shaped plasma. A simple experimental device was built in order to study the properties of high-density aerosol focusing for 1#22; m silica spheres. Preliminary results recover previous findings on aerodynamic focusing at low densities. At higher densities, it is demonstrated that the focusing properties change in a way which is consistent with a density dependent Stokes number.

  17. Chaos in a complex plasma

    SciTech Connect (OSTI)

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

    2005-08-15T23:59:59.000Z

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

  18. Nonlinear Plasma Waves Excitation by Intense Ion Beams in Background Plasma

    SciTech Connect (OSTI)

    Igor D. Kaganovich; Edward A. Startsev; Ronald C. Davidson

    2004-04-15T23:59:59.000Z

    Plasma neutralization of an intense ion pulse is of interest for many applications, including plasma lenses, heavy ion fusion, cosmic ray propagation, etc. An analytical electron fluid model has been developed to describe the plasma response to a propagating ion beam. The model predicts very good charge neutralization during quasi-steady-state propagation, provided the beam pulse duration {tau}{sub b} is much longer than the electron plasma period 2{pi}/{omega}{sub p}, where {omega}{sub p} = (4{pi}e{sup 2}n{sub p}/m){sup 1/2} is the electron plasma frequency and n{sub p} is the background plasma density. In the opposite limit, the beam pulse excites large-amplitude plasma waves. If the beam density is larger than the background plasma density, the plasma waves break. Theoretical predictions are compared with the results of calculations utilizing a particle-in-cell (PIC) code. The cold electron fluid results agree well with the PIC simulations for ion beam propagation through a background plasma. The reduced fluid description derived in this paper can provide an important benchmark for numerical codes and yield scaling relations for different beam and plasma parameters. The visualization of numerical simulation data shows complex collective phenomena during beam entry and exit from the plasma.

  19. ANALYSIS OF DATA FROM Z-PINCH MTF TARGET PLASMA EXPERIMENTS

    SciTech Connect (OSTI)

    F. WYSOCKI; J. TACCETTI; ET AL

    1999-04-01T23:59:59.000Z

    The Los Alamos National Laboratory Colt facility has been used to create target plasma for Magnetized Target Fusion (MTF). The primary results regarding magnetic field, plasma density, plasma temperature, and hot plasma lifetime are summarized and the suitability of these plasma targets for MTF is assessed.

  20. Cathodic Vacuum Arc Plasma of Thallium

    E-Print Network [OSTI]

    Yushkov, Georgy Yu.; Anders, Andre

    2006-01-01T23:59:59.000Z

    P. J. Martin, Handbook of Vacuum Arc Science and Technology.charge state distributions of vacuum arc plasmas: The originand the broadening of vacuum-arc ion charge state

  1. Plasma accelerator

    DOE Patents [OSTI]

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

    2002-01-01T23:59:59.000Z

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

  2. Boundary Plasma Turbulence Simulations for Tokamaks

    SciTech Connect (OSTI)

    Xu, X; Umansky, M; Dudson, B; Snyder, P

    2008-05-15T23:59:59.000Z

    The boundary plasma turbulence code BOUT models tokamak boundary-plasma turbulence in a realistic divertor geometry using modified Braginskii equations for plasma vorticity, density (ni), electron and ion temperature (T{sub e}; T{sub i}) and parallel momenta. The BOUT code solves for the plasma fluid equations in a three dimensional (3D) toroidal segment (or a toroidal wedge), including the region somewhat inside the separatrix and extending into the scrape-off layer; the private flux region is also included. In this paper, a description is given of the sophisticated physical models, innovative numerical algorithms, and modern software design used to simulate edge-plasmas in magnetic fusion energy devices. The BOUT code's unique capabilities and functionality are exemplified via simulations of the impact of plasma density on tokamak edge turbulence and blob dynamics.

  3. Plasma response to electron energy filter in large volume plasma device

    SciTech Connect (OSTI)

    Sanyasi, A. K.; Awasthi, L. M.; Mattoo, S. K.; Srivastava, P. K.; Singh, S. K.; Singh, R.; Kaw, P. K. [Institute for Plasma Research, Gandhinagar, 382 428 Gujarat (India)] [Institute for Plasma Research, Gandhinagar, 382 428 Gujarat (India)

    2013-12-15T23:59:59.000Z

    An electron energy filter (EEF) is embedded in the Large Volume Plasma Device plasma for carrying out studies on excitation of plasma turbulence by a gradient in electron temperature (ETG) described in the paper of Mattoo et al. [S. K. Mattoo et al., Phys. Rev. Lett. 108, 255007 (2012)]. In this paper, we report results on the response of the plasma to the EEF. It is shown that inhomogeneity in the magnetic field of the EEF switches on several physical phenomena resulting in plasma regions with different characteristics, including a plasma region free from energetic electrons, suitable for the study of ETG turbulence. Specifically, we report that localized structures of plasma density, potential, electron temperature, and plasma turbulence are excited in the EEF plasma. It is shown that structures of electron temperature and potential are created due to energy dependence of the electron transport in the filter region. On the other hand, although structure of plasma density has origin in the particle transport but two distinct steps of the density structure emerge from dominance of collisionality in the source-EEF region and of the Bohm diffusion in the EEF-target region. It is argued and experimental evidence is provided for existence of drift like flute Rayleigh-Taylor in the EEF plasma.

  4. Ion optical effects in a low pressure rf plasma

    SciTech Connect (OSTI)

    Oechsner, Hans; Paulus, Hubert [Institute for Surface and Thin Film Analysis IFOS and Department of Physics, Technical University of Kaiserslautern, D-67663 Kaiserslautern (Germany)] [Institute for Surface and Thin Film Analysis IFOS and Department of Physics, Technical University of Kaiserslautern, D-67663 Kaiserslautern (Germany)

    2013-11-15T23:59:59.000Z

    Ion optical effects in low pressure gas discharges are introduced as a novel input into low pressure plasma technology. They are based on appropriate geometrical plasma confinements which enable a control of the shape of internal density and potential distributions and, hence, the ion motion in the plasma bulk. Such effects are exemplified for an electron cyclotron wave resonance plasma in Ar at 1–5 × 10{sup ?3} millibars. The geometry of the plasma chamber is modified by a conical and a cylindrical insert. Computer simulations display spherical plasma density contours to be formed around the conical confinement. This effects an increase of the ratio of the ion currents into the conical and the cylindrical inserts which depends on the fourth power of the plasma electron temperature. A quantitative understanding of this behavior is presented. As another essential result, the shape of the internal plasma contours is found to be independent of the pressure controlled plasma parameters.

  5. HEAVY ION FUSION SCIENCE VIRTUAL NATIONAL LABORATORY 3nd QUARTER 2009 MILESTONE REPORT: Upgrade plasma source configuration and carry out initial experiments. Characterize improvements in focal spot beam intensity

    E-Print Network [OSTI]

    Lidia, S.

    2010-01-01T23:59:59.000Z

    FEPS plasma and the plasma in the final focus solenoid. TheI Final Focus Solenoid (FFS) in order to generate plasma onplasma sources (CAPS) streams from left to right into the final focus

  6. FUSION NUCLEAR SCIENCE PROGRAM & SUPPORTING FUSION NUCLEAR SCIENCE FACILITY (FNSF)

    E-Print Network [OSTI]

    FUSION NUCLEAR SCIENCE PROGRAM & SUPPORTING FUSION NUCLEAR SCIENCE FACILITY (FNSF): UPDATE · It was well recognized there were also critical materials and technology issues that needed to be addressed in order to apply the knowledge we gained about burning plasma state #12;FUSION NUCLEAR SCIENCE PROGRAM

  7. Plasma dynamics in a discharge produced by a pulsed dual frequency inductively coupled plasma source

    SciTech Connect (OSTI)

    Mishra, Anurag; Lee, Sehan [Department of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon, Gyeonggi-do 440-746 (Korea, Republic of); Yeom, Geun Y., E-mail: gyyeom@skku.edu [Department of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon, Gyeonggi-do 440-746, South Korea and SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon, Gyeonggi-do 440-746 (Korea, Republic of)

    2014-11-01T23:59:59.000Z

    Using a Langmuir probe, time resolved measurements of plasma parameters were carried out in a discharge produced by a pulsed dual frequency inductively coupled plasma source. The discharge was sustained in an argon gas environment at a pressure of 10 mTorr. The low frequency (P{sub 2} {sub MHz}) was pulsed at 1 kHz and a duty ratio of 50%, while high frequency (P{sub 13.56} {sub MHz}) was maintained in the CW mode. All measurements were carried out at the center of the discharge and 20?mm above the substrate. The results show that, at a particular condition (P{sub 2} {sub MHz}?=?200 W and P{sub 13.56} {sub MHz?}=?600 W), plasma density increases with time and stabilizes at up to ?200 ?s after the initiation of P{sub 2} {sub MHz} pulse at a plasma density of (2?×?10{sup 17} m{sup ?3}) for the remaining duration of pulse “on.” This stabilization time for plasma density increases with increasing P{sub 2} {sub MHz} and becomes ?300 ?s when P{sub 2} {sub MHz} is 600 W; however, the growth rate of plasma density is almost independent of P{sub 2} {sub MHz}. Interestingly, the plasma density sharply increases as the pulse is switched off and reaches a peak value in ?10 ?s, then decreases for the remaining pulse “off-time.” This phenomenon is thought to be due to the sheath modulation during the transition from “pulse on” to “pulse off” and partly due to RF noise during the transition period. The magnitude of peak plasma density in off time increases with increasing P{sub 2} {sub MHz}. The plasma potential and electron temperature decrease as the pulse develops and shows similar behavior to that of the plasma density when the pulse is switched off.

  8. Giant coercivity of dense nanostructured spark plasma sintered barium hexaferrite

    E-Print Network [OSTI]

    Giant coercivity of dense nanostructured spark plasma sintered barium hexaferrite F. Mazaleyrat and dense material together. In this paper, it is shown that the spark plasma sintering method (SPS) is able, Spark Plasma Sintering (SPS) allows to produce nonos- tructured Ba-ferrite with a density close to 90

  9. Vortex stabilized electron beam compressed fusion grade plasma

    SciTech Connect (OSTI)

    Hershcovitch, Ady [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.

    2014-03-19T23:59:59.000Z

    Most inertial confinement fusion schemes are comprised of highly compressed dense plasmas. Those schemes involve short, extremely high power, short pulses of beams (lasers, particles) applied to lower density plasmas or solid pellets. An alternative approach could be to shoot an intense electron beam through very dense, atmospheric pressure, vortex stabilized plasma.

  10. Application of Plasma Waveguides to High Energy Accelerators

    SciTech Connect (OSTI)

    Milchberg, Howard M

    2013-03-30T23:59:59.000Z

    The eventual success of laser-plasma based acceleration schemes for high-energy particle physics will require the focusing and stable guiding of short intense laser pulses in reproducible plasma channels. For this goal to be realized, many scientific issues need to be addressed. These issues include an understanding of the basic physics of, and an exploration of various schemes for, plasma channel formation. In addition, the coupling of intense laser pulses to these channels and the stable propagation of pulses in the channels require study. Finally, new theoretical and computational tools need to be developed to aid in the design and analysis of experiments and future accelerators. Here we propose a 3-year renewal of our combined theoretical and experimental program on the applications of plasma waveguides to high-energy accelerators. During the past grant period we have made a number of significant advances in the science of laser-plasma based acceleration. We pioneered the development of clustered gases as a new highly efficient medium for plasma channel formation. Our contributions here include theoretical and experimental studies of the physics of cluster ionization, heating, explosion, and channel formation. We have demonstrated for the first time the generation of and guiding in a corrugated plasma waveguide. The fine structure demonstrated in these guides is only possible with cluster jet heating by lasers. The corrugated guide is a slow wave structure operable at arbitrarily high laser intensities, allowing direct laser acceleration, a process we have explored in detail with simulations. The development of these guides opens the possibility of direct laser acceleration, a true miniature analogue of the SLAC RF-based accelerator. Our theoretical studies during this period have also contributed to the further development of the simulation codes, Wake and QuickPIC, which can be used for both laser driven and beam driven plasma based acceleration schemes. We will continue our development of advanced simulation tools by modifying the QuickPIC algorithm to allow for the simulation of plasma particle pick-up by the wake fields. We have also performed extensive simulations of plasma slow wave structures for efficient THz generation by guided laser beams or accelerated electron beams. We will pursue experimental studies of direct laser acceleration, and THz generation by two methods, ponderomotive-induced THz polarization, and THz radiation by laser accelerated electron beams. We also plan to study both conventional and corrugated plasma channels using our new 30 TW in our new lab facilities. We will investigate production of very long hydrogen plasma waveguides (5 cm). We will study guiding at increasing power levels through the onset of laser-induced cavitation (bubble regime) to assess the role played by the preformed channel. Experiments in direct acceleration will be performed, using laser plasma wakefields as the electron injector. Finally, we will use 2-colour ionization of gases as a high frequency THz source (<60 THz) in order for femtosecond measurements of low plasma densities in waveguides and beams.

  11. U S Burning Plasma Organization:U.S. Burning Plasma Organization: Supporting US Scientific Contributions to

    E-Print Network [OSTI]

    Community (TTF,...) US Technology Community · USBPO mission is to coordinate US Burning Plasma related research to advance science USBPO Director, Jim Van Dam, also serves as US IPO Chief Scientist, assuring

  12. Fusion Energy Sciences Program Mission

    E-Print Network [OSTI]

    Fusion Energy Sciences Program Mission The Fusion Energy Sciences (FES) program leads the national for an economically and environmentally attractive fusion energy source. The National Energy Policy states that fusion-heated) plasma, and the Fusion Energy Sciences Advisory Committee (FESAC) has concluded that the fusion program

  13. Dielectric covered hairpin probe for its application in reactive plasmas

    SciTech Connect (OSTI)

    Gogna, G. S.; Gaman, C.; Turner, M. M. [NCPST, School of Physical Sciences, Dublin City University, Dublin 9 (Ireland); Karkari, S. K. [Institute for Plasma Research Center, Bhat Gandhinagar, Gujarat 382428 (India)

    2012-07-23T23:59:59.000Z

    The hairpin probe is a well known technique for measuring local electron density in low temperature plasmas. In reactive plasmas, the probe characteristics are affected by surface sputtering, contamination, and secondary electron emission. At higher densities, the plasma absorbs the entire electromagnetic energy of hairpin and hence limits the density measurements. These issues can be resolved by covering the hairpin surface with a thin layer of dielectric. In this letter, the dielectric contribution to the probe characteristics is incorporated in a theory which is experimentally verified. The dielectric covering improves the performance of probe and also allows the hairpin tip to survive in reactive plasma where classical electrical probes are easily damaged.

  14. Laser beat wave excitation of terahertz radiation in a plasma slab

    SciTech Connect (OSTI)

    Chauhan, Santosh; Parashar, Jetendra, E-mail: j.p.parashar@gmail.com [Department of Applied Physics, Samrat Ashok Technological Institute, Vidisha 464001, Madhya Pradesh (India)

    2014-10-15T23:59:59.000Z

    Terahertz (THz) radiation generation by nonlinear mixing of lasers, obliquely incident on a plasma slab is investigated. Two cases are considered: (i) electron density profile is parabolic but density peak is below the critical density corresponding to the beat frequency, (ii) plasma boundaries are sharp and density is uniform. In both cases, nonlinearity arises through the ponderomotive force that gives rise to electron drift at the beat frequency. In the case of inhomogeneous plasma, non zero curl of the nonlinear current density gives rise to electromagnetic THz generation. In case of uniform plasma, the sharp density variation at the plasma boundaries leads to radiation generation. In a slab width of less than a terahertz wavelength, plasma density one fourth of terahertz critical density, laser intensities ?10{sup 17?}W/cm{sup 2} at 1??m, one obtains the THz intensity ?1?GW/cm{sup 2} at 3 THz radiation frequency.

  15. Effect of Inert Gas Additive Species on Cl(2) High Density Plasma Etching of Compound Semiconductors: Part II. InP, InSb, InGaP and InGaAs

    SciTech Connect (OSTI)

    Abernathy, C.R.; Cho, H.; Hahn, Y.B.; Hays, D.C.; Jung, K.B.; Pearton, S.J.; Shul, R.J.

    1998-12-17T23:59:59.000Z

    The effects of the additive noble gases He, Ar and Xe on chlorine-based Inductively Coupled Plasma etching of InP, InSb, InGaP and InGaAs were studied as a function of source power, chuck power and discharge composition. The etch rates of all materials with C12/He and C12/Xe are greater than with C12/Ar. Etch rates in excess of 4.8 pndmin for InP and InSb with C12/He or C12/Xe, 0.9 pndmin for InGaP with C12/Xe, and 3.8 prdmin for InGaAs with Clz/Xe were obtained at 750 W ICP power, 250 W rf power, - 1570 C12 and 5 mTorr. All three plasma chemistries produced smooth morphologies for the etched InGaP surfaces, while the etched surface of InP showed rough morphology under all conditions.

  16. Principles of Rotating Plasma in Plasma Propulsion Systems N. J. Fisch

    E-Print Network [OSTI]

    Principles of Rotating Plasma in Plasma Propulsion Systems N. J. Fisch Department of Astrophysical Sciences Princeton University 33rd International Electric Propulsion Conference (IEPC2013 in crossed electric and magnetic fields. This talk reviews at a tutorial level some of the interesting

  17. Solitary and shock waves in magnetized electron-positron plasma

    SciTech Connect (OSTI)

    Lu, Ding; Li, Zi-Liang; Abdukerim, Nuriman; Xie, Bai-Song, E-mail: bsxie@bnu.edu.cn [Key Laboratory of Beam Technology and Materials Modification of the Ministry of Education, and College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China)] [Key Laboratory of Beam Technology and Materials Modification of the Ministry of Education, and College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China)

    2014-02-15T23:59:59.000Z

    An Ohm's law for electron-positron (EP) plasma is obtained. In the framework of EP magnetohydrodynamics, we investigate nonrelativistic nonlinear waves' solutions in a magnetized EP plasma. In the collisionless limit, quasistationary propagating solitary wave structures for the magnetic field and the plasma density are obtained. It is found that the wave amplitude increases with the Mach number and the Alfvén speed. However, the dependence on the plasma temperature is just the opposite. Moreover, for a cold EP plasma, the existence range of the solitary waves depends only on the Alfvén speed. For a hot EP plasma, the existence range depends on the Alfvén speed as well as the plasma temperature. In the presence of collision, the electromagnetic fields and the plasma density can appear as oscillatory shock structures because of the dissipation caused by the collisions. As the collision frequency increases, the oscillatory shock structure becomes more and more monotonic.

  18. NSTX Plasma Response to Lithium Coated Divertor

    SciTech Connect (OSTI)

    H.W. Kugel, M.G. Bell, J.P. Allain, R.E. Bell, S. Ding, S.P. Gerhardt, M.A. Jaworski, R. Kaita, J. Kallman, S.M. Kaye, B.P. LeBlanc, R. Maingi, R. Majeski, R. Maqueda, D.K. Mansfield, D. Mueller, R. Nygren, S.F. Paul, R. Raman, A.L. Roquemore, S.A. Sabbagh, H. Schneider, C.H. Skinner, V.A. Soukhanovskii, C.N. Taylor, J.R. Timberlak, W.R. Wampler, L.E. Zakharov, S.J. Zweben, and the NSTX Research Team

    2011-01-21T23:59:59.000Z

    NSTX experiments have explored lithium evaporated on a graphite divertor and other plasma facing components in both L- and H- mode confinement regimes heated by high-power neutral beams. Improvements in plasma performance have followed these lithium depositions, including a reduction and eventual elimination of the HeGDC time between discharges, reduced edge neutral density, reduced plasma density, particularly in the edge and the SOL, increased pedestal electron and ion temperature, improved energy confinement and the suppression of ELMs in the H-mode. However, with improvements in confinement and suppression of ELMs, there was a significant secular increase in the effective ion charge Zeff and the radiated power in H-mode plasmas as a result of increases in the carbon and medium-Z metallic impurities. Lithium itself remained at a very low level in the plasma core, <0.1%. Initial results are reported from operation with a Liquid Lithium Divertor (LLD) recently installed.

  19. Taylor/FESAC Priorities/July 18, 2012 Fusion Energy Science Program Priorities

    E-Print Network [OSTI]

    Base Plasma science Engineering Science Innovative Experiments, Theory/modeling Students Workforce #12 materials fuel cycle ITER high gain BP Physics DEMO net electricity Excellent Science and Innovation are strengths of the U. S. Magnetic Fusion Program Strong Scientific Base Plasma science Engineering Science

  20. Runaway electrons in a fully and partially ionized nonideal plasma

    SciTech Connect (OSTI)

    Ramazanov, T.S.; Turekhanova, K.M. [Al Farabi Kazakh National University, IETP, Tole bi 96a, Almaty 050012 (Kazakhstan)

    2005-10-01T23:59:59.000Z

    This paper reports on a study of electron runaway for a nonideal plasma in an external electric field. Based on pseudopotential models of nonideal fully and partially ionized plasmas, the friction force was derived as a function of electron velocities. Dependences of the electron free path on plasma density and nonideality parameters were obtained. The impact of the relative number of runaway electrons on their velocity and temperature was considered for classical and semiclassical models of a nonideal plasma. It has been shown that for the defined intervals of the coupled plasma parameter, the difference between the relative numbers of runaway electron values is essential for various plasma models.

  1. On interaction of large dust grains with fusion plasma

    SciTech Connect (OSTI)

    Krasheninnikov, S. I.; Smirnov, R. D. [University of California at San Diego, La Jolla, California 92093 (United States)

    2009-11-15T23:59:59.000Z

    So far the models used to study dust grain-plasma interactions in fusion plasmas neglect the effects of dust material vapor, which is always present around dust in rather hot and dense edge plasma environment in fusion devices. However, when the vapor density and/or the amount of ionized vapor atoms become large enough, they can alter the grain-plasma interactions. Somewhat similar processes occur during pellet injection in fusion plasma. In this brief communication the applicability limits of the models ignoring vapor effects in grain-plasma interactions are obtained.

  2. Measurements of plasma bremsstrahlung and plasma energy density produced by electron cyclotron resonance ion source plasmas

    E-Print Network [OSTI]

    Noland, Jonathan David

    2011-01-01T23:59:59.000Z

    30] Glenn F. Knoll. Radiation Detection and Measurement.in many textbooks on radiation detection[30], and a brief

  3. Breakthrough Science at NERSC Harvey Wasserman

    E-Print Network [OSTI]

    Biological & Environmental Research BES Basic Energy Sciences FES Fusion Energy Sciences HEP High Energy Physics NP Nuclear Physics NERSC 2008 Allocations By DOE Office #12;Science View of Workload NERSC 2008...) 10 #12;Six Breakthrough Science Stories · Nuclear Physics · Geochemistry · Plasma Turbulence

  4. Progress on Plasma Lens Experiment at the Final Focus Test Beam *

    E-Print Network [OSTI]

    Progress on Plasma Lens Experiment at the Final Focus Test Beam * S. Chattopadhyay 1 , P. Chen 2 Collaboration proposed and has been approved to perform the Plasma Lens Experiment at the Final Focus Test Beam of the experiment are to study plasma focusing of high energy, high density particle beams; to investigate plasma

  5. Multi-GeV Energy Gain in a Plasma-Wakefield Accelerator M. J. Hogan,1

    E-Print Network [OSTI]

    Jalali. Bahram

    m at the entrance of a 10 cm long column of lithium vapor with density 2:8 1017 atoms=cm3. The electron bunch fully ionizes the lithium vapor to create a plasma and then expels the plasma electrons-plasma interactions have demonstrated focusing gradients of MT=m [1] while laser plasma interactions have demonstrated

  6. Ac#vi#es of the US Burning Plasma Organiza#on

    E-Print Network [OSTI]

    =ons · USBPO ­ Coordinates US burning plasma research, to advance scien=fic understanding USBPO organizes the US Fusion Energy Science community to support burning plasma research 5 Charles Greenfield (Director) Amanda Hubbard (Deputy Director) Nermin

  7. E-Print Network 3.0 - atmospheric plasma-treated 3d Sample Search...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    OF MATERIALS SCIENCE LETTERS 17 (1998) 20832086 Effect of oxygen plasma treatment on SiO2 aerogel lms Summary: , microstructure, and electrical proper- ties of the oxygen plasma...

  8. Effect of argon addition on plasma parameters and dust charging in hydrogen plasma

    SciTech Connect (OSTI)

    Kakati, B., E-mail: bharatkakati15@gmail.com; Kausik, S. S.; Saikia, B. K. [Centre of Plasma Physics-Institute for Plasma Research, Nazirakhat, Sonapur, Kamrup 782402, Assam (India); Bandyopadhyay, M.; Saxena, Y. C. [Institute for Plasma Research, Bhat, Gandhinagar 382 428 (India)

    2014-10-28T23:59:59.000Z

    Experimental results on effect of adding argon gas to hydrogen plasma in a multi-cusp dusty plasma device are reported. Addition of argon modifies plasma density, electron temperature, degree of hydrogen dissociation, dust current as well as dust charge. From the dust charging profile, it is observed that the dust current and dust charge decrease significantly up to 40% addition of argon flow rate in hydrogen plasma. But beyond 40% of argon flow rate, the changes in dust current and dust charge are insignificant. Results show that the addition of argon to hydrogen plasma in a dusty plasma device can be used as a tool to control the dust charging in a low pressure dusty plasma.

  9. Plasma generation for controlled microwave-reflecting surfaces in plasma antennas

    SciTech Connect (OSTI)

    Bliokh, Yury P.; Felsteiner, Joshua; Slutsker, Yakov Z. [Physics Department, Technion-Israel Institute of Technology, 32000 Haifa (Israel)

    2014-04-28T23:59:59.000Z

    The idea of replacing metal antenna elements with equivalent plasma objects has long been of interest because of the possibility of switching the antenna on and off. In general, two kinds of designs have so far been reported: (a) Separate plasma “wires” which are thin glass tubes filled with gas, where plasma appears due to discharge inside. (b) Reflecting surfaces, consisting of tightly held plasma wires or specially designed large discharge devices with magnetic confinement. The main disadvantages of these antennas are either large weight and size or too irregular surfaces for proper reflection. To design a microwave plasma antenna in the most common radar wavelength range of 1–3?cm with a typical gain of 30?dB, a smooth plasma mirror having a 10–30?cm diameter and a proper curvature is required. The plasma density must be 10{sup 12}–10{sup 14}?cm{sup ?3} in order to exceed the critical density for the frequency of the electromagnetic wave. To achieve this we have used a ferromagnetic inductively coupled plasma (FICP) source, where a thin magnetic core of a large diameter is fully immersed in the plasma. In the present paper, we show a way to adapt the FICP source for creating a flat switchable microwave plasma mirror with an effective diameter of 30?cm. This mirror was tested as a microwave reflector and there was found no significant difference when compared with a copper plate having the same diameter.

  10. An experimental study and modeling of Transformer-Coupled Toroidal Plasma processing of materials

    E-Print Network [OSTI]

    Bai, Bo, Ph. D. Massachusetts Institute of Technology

    2006-01-01T23:59:59.000Z

    The Transformer Coupled Toroidal Plasma (TCTP) source uses a high power density plasma formed in a toroidal-shaped chamber by transformer coupling using a magnetic core. The objectives of the thesis are (1) to characterize ...

  11. Plasma ignition and steady state simulations of the Linac4 H$^{-}$ ion source

    E-Print Network [OSTI]

    Mattei, S; Yasumoto, M; Hatayama, A; Lettry, J; Grudiev, A

    2013-01-01T23:59:59.000Z

    The RF heating of the plasma in the Linac4 H- ion source has been simulated using an Particle-in-Cell Monte Carlo Collision method (PIC-MCC). This model is applied to investigate the plasma formation starting from an initial low electron density of 1012 m-3 and its stabilization at 1018 m-3. The plasma discharge at low electron density is driven by the capacitive coupling with the electric field generated by the antenna, and as the electron density increases the capacitive electric field is shielded by the plasma and induction drives the plasma heating process. Plasma properties such as e-/ion densities and energies, sheath formation and shielding effect are presented and provide insight to the plasma properties of the hydrogen plasma.

  12. Electronically swept millimetre-wave interferometer for spatially resolved measurement of plasma electron

    E-Print Network [OSTI]

    Howard, John

    electron density John Howard and David Oliver Plasma Research Laboratory, Research School of Physical, located in the Plasma Research Laboratory at the Australian National University, is a flexible, medium

  13. affordable near-term burning-plasma: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Physics and Fusion Websites Summary: ons USBPO - Coordinates US burning plasma research, to advance scienfic understanding USBPO organizes the US Fusion Energy Science...

  14. A restoration model of distorted electron density in wave-cutoff probe measurement

    SciTech Connect (OSTI)

    Jun, Hyun-Su, E-mail: mtsconst@kaist.ac.kr; Lee, Yun-Seong [Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 305-701 (Korea, Republic of)] [Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 305-701 (Korea, Republic of)

    2014-02-15T23:59:59.000Z

    This study investigates the problem of electron density distortion and how the density can be restored in a wave-cutoff probe. Despite recent plasma diagnostics research using a wave-cutoff probe, the problem of electron density distortion caused by plasma conditions has not been resolved. Experimental results indicate that electron density measured using the wave-cutoff method is highly susceptible to variations in the probe tip gap. This electron density distortion is caused by the bulk plasma disturbance between probe tips, and it must be removed for calculating the absolute electron density. To do this, a detailed analytic model was developed using the power balance equation near probe tips. This model demonstrates the characteristics of plasma distortion in wave-cutoff probe measurement and successfully restored the absolute value of electron density with varying probe tip gaps.

  15. Multi-scale investigation of sheared flows in magnetized plasmas

    SciTech Connect (OSTI)

    Thomas, Jr., Dr. Edward

    2014-09-19T23:59:59.000Z

    Flows parallel and perpendicular to magnetic fields in a plasma are important phenomena in many areas of plasma science research. The presence of these spatially inhomogeneous flows is often associated with the stability of the plasma. In fusion plasmas, these sheared flows can be stabilizing while in space plasmas, these sheared flows can be destabilizing. Because of this, there is broad interest in understanding the coupling between plasma stability and plasma flows. This research project has engaged in a study of the plasma response to spatially inhomogeneous plasma flows using three different experimental devices: the Auburn Linear Experiment for Instability Studies (ALEXIS) and the Compact Toroidal Hybrid (CTH) stellarator devices at Auburn University, and the Space Plasma Simulation Chamber (SPSC) at the Naval Research Laboratory. This work has shown that there is a commonality of the plasma response to sheared flows across a wide range of plasma parameters and magnetic field geometries. The goal of this multi-device, multi-scale project is to understand how sheared flows established by the same underlying physical mechanisms lead to different plasma responses in fusion, laboratory, and space plasmas.

  16. Surface-Plasma Interaction on the Moon

    SciTech Connect (OSTI)

    Horanyi, M.; Wang, X.; Robertson, S.; Sternovsky, Z. [University of Colorado, Boulder, CO 80309-0392 (United States)

    2008-09-07T23:59:59.000Z

    The electrostatic levitation and transport of lunar dust remains a controversial science issue since the Apollo era. As a function of time and location, the lunar surface is exposed to solar wind plasma, UV radiation, and/or the plasma environment of our magnetosphere. Dust grains on the lunar surface emit and absorb plasma particles and are exposed to solar UV photons. There are several in situ and remote sensing observations that indicate that dusty plasma processes are responsible for the mobilization and transport of lunar soil. We briefly discuss the existing observations, and report on a series of experiments that address some of the most relevant processes acting on dusty surfaces exposed to plasmas and UV radiation.

  17. Landau Diamagnetism of Degenerate Collisional Plasma

    E-Print Network [OSTI]

    A. V. Latyshev; A. A. Yushkanov

    2010-07-05T23:59:59.000Z

    For the first time the kinetic description of Landau diamagnetism for degenerate collisional plasma is given. The correct expression for transverse electric conductivity of the quantum plasma, found by authors (see arXiv:1002.1017 [math-ph] 4 Feb 2010) is used. In work S. Dattagupta, A.M. Jayannavar and N. Kumar [Current science, V. 80, No. 7, 10 April, 2001] was discussed the important problem of dissipation (collisions) influence on Landau diamagnetism. The analysis of this problem is given with the use of exact expression for transverse conductivity of quantum plasma.

  18. Direct measurements of the ionization profile in krypton helicon plasmas

    SciTech Connect (OSTI)

    Magee, R. M.; Galante, M. E.; McCarren, D. W.; Scime, E. E. [Department of Physics, West Virginia University, Morgantown, West Virginia 26506 (United States); Gulbrandsen, N. [Department of Physics and Technology, Faculty of Science, University of Tromso, N-9037 Tromso (Norway)

    2012-12-15T23:59:59.000Z

    Helicons are efficient plasma sources, capable of producing plasma densities of 10{sup 19} m{sup -3} with only 100 s W of input rf power. There are often steep density gradients in both the neutral density and plasma density, resulting in a fully ionized core a few cm wide surrounded by a weakly ionized plasma. The ionization profile is usually not well known because the neutral density is typically inferred from indirect spectroscopic measurements or from edge pressure gauge measurements. We have developed a two photon absorption laser induced fluorescence (TALIF) diagnostic capable of directly measuring the neutral density profile. We use TALIF in conjunction with a Langmuir probe to measure the ionization fraction profile as a function of driving frequency, magnetic field, and input power. It is found that when the frequency of the driving wave is greater than a critical frequency, f{sub c} Almost-Equal-To 3f{sub lh}, where f{sub lh} is the lower hybrid frequency at the antenna, the ionization fraction is small (0.1%) and the plasma density low (10{sup 17} m{sup -3}). As the axial magnetic field is increased, or, equivalently, the driving frequency decreased, a transition is observed. The plasma density increases by a factor of 10 or more, the plasma density profile becomes strongly peaked, the neutral density profile becomes strongly hollow, and the ionization fraction in the core approaches 100%. Neutral depletion in the core can be caused by a number of mechanisms. We find that in these experiments the depletion is due primarily to plasma pressure and neutral pumping.

  19. Optimized ECR plasma apparatus with varied microwave window thickness

    DOE Patents [OSTI]

    Berry, L.A.

    1995-11-14T23:59:59.000Z

    The present invention describes a technique to control the radial profile of microwave power in an ECR plasma discharge. In order to provide for a uniform plasma density to a specimen, uniform energy absorption by the plasma is desired. By controlling the radial profile of the microwave power transmitted through the microwave window of a reactor, the profile of the transmitted energy to the plasma can be controlled in order to have uniform energy absorption by the plasma. An advantage of controlling the profile using the window transmission characteristics is that variations to the radial profile of microwave power can be made without changing the microwave coupler or reactor design. 9 figs.

  20. ECR apparatus with magnetic coil for plasma refractive index control

    DOE Patents [OSTI]

    Berry, L.A.

    1994-04-26T23:59:59.000Z

    The present invention describes a technique to control the radial profile of microwave power in an ECR plasma discharge. In order to provide for a uniform plasma density to a specimen, uniform energy absorption by the plasma is desired. By controlling the radial profile of the microwave power transmitted through the microwave window of a reactor, the profile of the transmitted energy to the plasma can be controlled in order to have uniform energy absorption by the plasma. An advantage of controlling the profile using the window transmission characteristics is that variations to the radial profile of microwave power can be made without changing the microwave coupler or reactor design. 9 figures.

  1. Self-consistent quasiparticle model for quark-gluon plasma

    E-Print Network [OSTI]

    Vishnu M. Bannur

    2006-09-19T23:59:59.000Z

    Here we present a self-consistent quasi-particle model for quark-gluon plasma and apply it to explain the non-ideal behaviour seen in lattice simulations. The basic idea, borrowed from electrodynamic plasma, is that the gluons acquire mass as it propagates through plasma due to collective effects and is approximately equal to the plasma frequency. The statistical mechanics and thermodynamics of such a system is studied by treating it as an ideal gas of massive gluons. Since mass or plasma frequency depends on density, which itself is a thermodynamic quantity, the whole problem need to be solved self-consistently.

  2. ECR apparatus with magnetic coil for plasma refractive index control

    DOE Patents [OSTI]

    Berry, Lee A. (Oak Ridge, TN)

    1994-01-01T23:59:59.000Z

    The present invention describes a technique to control the radial profile of microwave power in an ECR plasma discharge. In order to provide for a uniform plasma density to a specimen, uniform energy absorption by the plasma is desired. By controlling the radial profile of the microwave power transmitted through the microwave window of a reactor, the profile of the transmitted energy to the plasma can be controlled in order to have uniform energy absorption by the plasma. An advantage of controlling the profile using the window transmission characteristics is that variations to the radial profile of microwave power can be made without changing the microwave coupler or reactor design.

  3. Optimized ECR plasma apparatus with varied microwave window thickness

    DOE Patents [OSTI]

    Berry, Lee A. (Oak Ridge, TN)

    1995-01-01T23:59:59.000Z

    The present invention describes a technique to control the radial profile of microwave power in an ECR plasma discharge. In order to provide for a uniform plasma density to a specimen, uniform energy absorption by the plasma is desired. By controlling the radial profile of the microwave power transmitted through the microwave window of a reactor, the profile of the transmitted energy to the plasma can be controlled in order to have uniform energy absorption by the plasma. An advantage of controlling the profile using the window transmission characteristics is that variations to the radial profile of microwave power can be made without changing the microwave coupler or reactor design.

  4. Effect of Lithium PFC Coatings on NSTX Density Control

    SciTech Connect (OSTI)

    Kugel, H W; Bell, M G; Bush, C; Gates, D; Gray, T; Kaita, R; Leblanc, B; Maingi, R; Majeski, R; Mansfield, D; Mueller, D; Raman, R; Roquemore, A L; Sabbagh, S; Skinner, C H; Soukhanovskii, V; Stevenson, T; Zakharov, L

    2006-08-21T23:59:59.000Z

    Lithium coatings on the graphite plasma facing components (PFCs) in NSTX are being investigated as a tool for density profile control and reducing the recycling of hydrogen isotopes. Repeated lithium pellet injection into Center Stack Limited and Lower Single Null Ohmic Helium Discharges were used to coat graphite surfaces that had been pre-conditioned with Ohmic Helium Discharges of the same shape to reduce their contribution to hydrogen isotope recycling. The following deuterium NBI reference discharges exhibited a reduction in density by a factor of about 3 for limited and 2 for diverted plasmas respectively, and peaked density profiles. Recently, a lithium evaporator has been used to apply thin coatings on conditioned and unconditioned PFCs. Effects on the plasma density and the impurities were obtained by pre-conditioning the PFCs with ohmic helium discharges, and performing the first deuterium NBI discharge as soon as possible after applying the lithium coating.

  5. Plasma power measurement and hysteresis in the E-H transition of a rf inductively coupled plasma system

    SciTech Connect (OSTI)

    Daltrini, A. M.; Moshkalev, S. A. [Universidade Estadual de Campinas, Unicamp, Center for Semiconductor Components, P.O. Box 6061, Campinas SP 13083-870 (Brazil); Morgan, T. J. [Department of Physics, Wesleyan University, Middletown, Connecticut 06457 (United States); Piejak, R. B.; Graham, W. G. [Centre for Plasma Physics, Department of Physics and Astronomy, Queen's University Belfast BT 7 1NN, Northern Ireland (United Kingdom)

    2008-02-11T23:59:59.000Z

    An experimental investigation of the argon plasma behavior near the E-H transition in an inductively coupled Gaseous Electronics Conference reference cell is reported. Electron density and temperature, ion density, argon metastable density, and optical emission measurements have been made as function of input power and gas pressure. When plotted versus plasma power, applied power corrected for coil and hardware losses, no hysteresis is observed in the measured plasma parameter dependence at the E-H mode transition. This suggests that hysteresis in the E-H mode transition is due to ignoring inherent power loss, primarily in the matching system.

  6. Spectroscopic Determination of the Magnetic Fields in Exploding Wire and X-pinch Plasmas

    SciTech Connect (OSTI)

    Hammer, David A.

    2013-12-19T23:59:59.000Z

    In this report, we summarize the progress that was made toward developing a new magnetic field diagnostic known as Zeeman Broadening for current carrying high energy density plasmas.

  7. Plasma Physics

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's Possible for RenewableSpeedingBiomassPPPOPetroleum38 (1996) A213-A225. Printed in the UK4 Plasma

  8. Quantum plasma effects in the classical regime

    E-Print Network [OSTI]

    G. Brodin; M. Marklund; G. Manfredi

    2008-02-01T23:59:59.000Z

    For quantum effects to be significant in plasmas it is often assumed that the temperature over density ratio must be small. In this paper we challenge this assumption by considering the contribution to the dynamics from the electron spin properties. As a starting point we consider a multicomponent plasma model, where electrons with spin up and spin down are regarded as different fluids. By studying the propagation of Alfv\\'{e}n wave solitons we demonstrate that quantum effects can survive in a relatively high-temperature plasma. The consequences of our results are discussed.

  9. Dependence of plasma characteristics on dc magnetron sputter parameters

    SciTech Connect (OSTI)

    Wu, S.Z. [Recording Media Operation, Seagate Technology, 47010 Kato Road, Fremont, California 94538 (United States)

    2005-10-15T23:59:59.000Z

    Plasma discharge characteristics of a dc magnetron system were measured by a single Langmuir probe at the center axis of the dual-side process chamber. Plasma potential, floating potential, electron and ion densities, and electron temperature were extracted with varying dc power and gas pressure during sputter deposition of a metal target; strong correlations were shown between these plasma parameters and the sputter parameters. The electron density was controlled mostly by secondary electron generation in constant power mode, while plasma potential reflects the confinement space variation due to change of discharge voltage. When discharge pressure was varied, plasma density increases with the increased amount of free stock molecules, while electron temperature inversely decreased, due to energy-loss collision events. In low-pressure discharges, the electron energy distribution function measurements show more distinctive bi-Maxwellian distribution, with the fast electron temperature gradually decreases with increased gas pressure.

  10. SCIENCE CHINA Technological Sciences

    E-Print Network [OSTI]

    Wang, Zhong L.

    SCIENCE CHINA Technological Sciences © Science China Press and Springer-Verlag Berlin Heidelberg and Nanosystems, Chinese Academy of Sciences, Beijing 100083, China; 2 Institute of Theoretical Physics, Lanzhou University, Lanzhou 730000, China; 3 School of Material Science and Engineering, Georgia Institute

  11. Shock compression of low-density foams

    SciTech Connect (OSTI)

    Holmes, N.C.

    1993-07-01T23:59:59.000Z

    Shock compression of very low density micro-cellular materials allows entirely new regimes of hot fluid states to be investigated experimentally. Using a two-stage light-gas gun to generate strong shocks, temperatures of several eV are readily achieved at densities of roughly 0.5--1 g/cm{sup 3} in large, uniform volumes. The conditions in these hot, expanded fluids are readily found using the Hugoniot jump conditions. We will briefly describe the basic methodology for sample preparation and experimental measurement of shock velocities. We present data for several materials over a range of initial densities. This paper will explore the applications of these methods for investigations of equations of state and phase diagrams, spectroscopy, and plasma physics. Finally, we discus the need for future work on these and related low-density materials.

  12. Analytical and Numerical Studies of the Complex Interaction of a Fast Ion Beam Pulse with a Background Plasma

    E-Print Network [OSTI]

    Kaganovich, Igor

    ]. In this paper, we focus on the nonlinear case where the plasma density has an arbitrary value compared with a Background Plasma Igor D. Kaganovich1 , Edward A. Startsev1 and Ronald C. Davidson1 1 Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543, USA Received September 8, 2003 Abstract Plasma

  13. Oblique interactions of dust density waves

    SciTech Connect (OSTI)

    Wang, Zhelchui [Los Alamos National Laboratory; Li, Yang - Fang [MAX-PLANCK INSTITUTE; Hou, Lujing [MAX-PLANCK INSTITUTE; Jiang, Ke [MAX-PLANCK INSTITUTE; Wu, De - Jin [CHINA; Thomas, Hubertus M [MAX-PLANCK INSTITUTE; Morfill, Gregor E [MAX-PLANCK INSTITUTE

    2010-01-01T23:59:59.000Z

    Self-excited dust density waves (DDWs) are studied in a striped electrode device. In addition to the usual perpendicularly (with respect to the electrode) propagating DDWs, which have been frequently observed in dusty plasma experiments on the ground, a low-frequency oblique mode is also observed. This low-frequency oblique DDW has a frequency much lower than the dust plasma frequency and its spontaneous excitation is observed even with a very low dust density. It is found that the low-frequency oblique mode can exist either separately or together with the usual perpendicular mode. In the latter case, a new mode arises as a result of the interactions between the perpendicular and the oblique modes. The experiments show that these three modes satisfy the wave coupling conditions in both the frequencies and the wave-vectors.

  14. Effect of surface derived hydrocarbon impurities on Ar plasma properties

    SciTech Connect (OSTI)

    Fox-Lyon, Nick; Oehrlein, Gottlieb S., E-mail: Oehrlein@umd.edu [Department of Materials Science and Engineering and the Institute for Research and Applied Physics, University of Maryland, College Park, MD 20742 (United States); Godyak, Valery [Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI 48109-2122 (United States)

    2014-05-15T23:59:59.000Z

    The authors report on Langmuir probe measurements that show that hydrocarbon surfaces in contact with Ar plasma cause changes of electron energy distribution functions due to the flux of hydrogen and carbon atoms released by the surfaces. The authors compare the impact on plasma properties of hydrocarbon species gasified from an etching hydrocarbon surface with injection of gaseous hydrocarbons into Ar plasma. They find that both kinds of hydrocarbon injections decrease electron density and slightly increase electron temperatures of low pressure Ar plasma. For low percentages of impurities (?1% impurity in Ar plasma explored here), surface-derived hydrocarbon species and gas phase injected hydrocarbon molecules cause similar changes of plasma properties for the same number of hydrocarbon molecules injected into Ar with a decrease in electron density of ?4%.

  15. Course: FUSION SCIENCE AND ENGINEERING Universit degli Studi di Padova

    E-Print Network [OSTI]

    Cesare, Bernardo

    the subject of controlled thermonuclear fusion in magnetically confined plasmas. Both fusion science of Controlled Thermonuclear Fusion, b) Engineering of a Magnetically Confined Fusion Reactor, c) ExperimentalCourse: FUSION SCIENCE AND ENGINEERING Università degli Studi di Padova in agreement

  16. Pair densities in density functional theory

    E-Print Network [OSTI]

    Chen, Huajie

    2015-01-01T23:59:59.000Z

    The exact interaction energy of a many-electron system is determined by the electron pair density, which is not well-approximated in standard Kohn-Sham density functional models. Here we study the (complicated but well-defined) exact universal map from density to pair density. We show that many common functionals, including the most basic version of the LDA (Dirac exchange with no correlation contribution), arise from particular approximations of this map. We develop an algorithm to compute the map numerically, and apply it to one-parameter families {a*rho(a*x)} of one-dimensional homogeneous and inhomogeneous single-particle densities. We observe that the pair density develops remarkable multiscale patterns which strongly depend on both the particle number and the "width" 1/a of the single-particle density. The simulation results are confirmed by rigorous asymptotic results in the limiting regimes a>>1 and a<<1. For one-dimensional homogeneous systems, we show that the whole spectrum of patterns is rep...

  17. Observation of pressure gradient and related flow rate effect on the plasma parameters in plasma processing reactor

    SciTech Connect (OSTI)

    Lee, Hyo-Chang; Kim, Aram; Chung, Chin-Wook [Department of Electrical Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Moon, Se Youn [Solar Energy Group, LG Electronics Advanced Research Institute, 16 Woomyeon-Dong, Seocho-Gu, Seoul 137-724 (Korea, Republic of)

    2011-02-15T23:59:59.000Z

    In industrial plasma processes, flow rate has been known to a key to control plasma processing results and has been discussed with reactive radical density, gas residence time, and surface reaction. In this study, it was observed that the increase in the flow rate can also change plasma parameters (electron temperature and plasma density) and electron energy distribution function in plasma processing reactor. Based on the measurement of gas pressure between the discharge region and the pumping port region, the considerable differences in the gas pressure between the two regions were found with increasing flow rate. It was also observed that even in the discharge region, the pressure gradient occurs at the high gas flow rate. This result shows that increasing the flow rate results in the pressure gradient and causes the changes in the plasma parameters.

  18. Greg Hammett Imperial College, London & Princeton Plasma Physics Lab

    E-Print Network [OSTI]

    Hammett, Greg

    Corona & Wind Gyrokinetic Simulations Needed & In Progress #12;MHD Turbulence in Astrophysical Plasmas Medium Power Spectrum Of Electron Density Fluctuations Wavenumber (m-1) Power law over ~ 12 orders more & more nonlinear Hypothesize "critical balance": linear time ~ nonlinear time Anisotropic

  19. Ultra-High Intensity Magnetic Field Generation in Dense Plasma

    SciTech Connect (OSTI)

    Fisch, Nathaniel J

    2014-01-08T23:59:59.000Z

    I. Grant Objective The main objective of this grant proposal was to explore the efficient generation of intense currents. Whereasthefficient generation of electric current in low-­?energy-­? density plasma has occupied the attention of the magnetic fusion community for several decades, scant attention has been paid to carrying over to high-­?energy-­? density plasma the ideas for steady-­?state current drive developed for low-­?energy-­? density plasma, or, for that matter, to inventing new methodologies for generating electric current in high-­?energy-­?density plasma. What we proposed to do was to identify new mechanisms to accomplish current generation, and to assess the operation, physics, and engineering basis of new forms of current drive in regimes appropriate for new fusion concepts.

  20. Measurements of an expanding surface flashover plasma

    SciTech Connect (OSTI)

    Harris, J. R., E-mail: john.harris@colostate.edu [Department of Electrical and Computer Engineering, Colorado State University, Fort Collins, Colorado 80523 (United States)

    2014-05-21T23:59:59.000Z

    A better understanding of vacuum surface flashover and the plasma produced by it is of importance for electron and ion sources, as well as advanced accelerators and other vacuum electronic devices. This article describes time-of-flight and biased-probe measurements made on the expanding plasma generated from a vacuum surface flashover discharge. The plasma expanded at velocities of 1.2–6.5?cm/?s, and had typical densities of 10{sup 10}–10{sup 12}?cm{sup ?3}. The expansion velocity of the plasma leading edge often exhibited a sharp increase at distances of about 50?mm from the discharge site. Comparison with biased-probe data suggests that, under most conditions, the plasma leading edge was dominated by negative ions, with the apparent increase in velocity being due to fast H{sup ?} overtaking slower, heavier ions. In some cases, biased-probe data also showed abrupt discontinuities in the plasma energy distribution co-located with large changes in the intercepted plasma current, suggesting the presence of a shock in the leading edge of the expanding plasma.

  1. Computational Methods for Collisional Plasma Physics

    SciTech Connect (OSTI)

    Lasinski, B F; Larson, D J; Hewett, D W; Langdon, A B; Still, C H

    2004-02-18T23:59:59.000Z

    Modeling the high density, high temperature plasmas produced by intense laser or particle beams requires accurate simulation of a large range of plasma collisionality. Current simulation algorithms accurately and efficiently model collisionless and collision-dominated plasmas. The important parameter regime between these extremes, semi-collisional plasmas, has been inadequately addressed to date. LLNL efforts to understand and harness high energy-density physics phenomena for stockpile stewardship require accurate simulation of such plasmas. We have made significant progress towards our goal: building a new modeling capability to accurately simulate the full range of collisional plasma physics phenomena. Our project has developed a computer model using a two-pronged approach that involves a new adaptive-resolution, ''smart'' particle-in-cell algorithm: complex particle kinetics (CPK); and developing a robust 3D massively parallel plasma production code Z3 with collisional extensions. Our new CPK algorithms expand the function of point particles in traditional plasma PIC models by including finite size and internal dynamics. This project has enhanced LLNL's competency in computational plasma physics and contributed to LLNL's expertise and forefront position in plasma modeling. The computational models developed will be applied to plasma problems of interest to LLNL's stockpile stewardship mission. Such problems include semi-collisional behavior in hohlraums, high-energy-density physics experiments, and the physics of high altitude nuclear explosions (HANE). Over the course of this LDRD project, the world's largest fully electromagnetic PIC calculation was run, enabled by the adaptation of Z3 to the Advanced Simulation and Computing (ASCI) White system. This milestone calculation simulated an entire laser illumination speckle, brought new realism to laser-plasma interaction simulations, and was directly applicable to laser target physics. For the first time, magnetic fields driven by Raman scatter have been observed. Also, Raman rescatter was observed in 2D. This code and its increased suite of dedicated diagnostics are now playing a key role in studies of short-pulse, high-intensity laser matter interactions. In addition, a momentum-conserving electron collision algorithm was incorporated into Z3. Finally, Z3's portability across diverse MPP platforms enabled it to serve the LLNL computing community as a tool for effectively utilizing new machines.

  2. Interparticle interaction and transport processes in dense semiclassical plasmas

    SciTech Connect (OSTI)

    Baimbetov, F.B.; Giniyatova, Sh.G. [Department of Physics, Kazakh National University, Tole Bi 96, Almaty 480012 (Kazakhstan)

    2005-04-15T23:59:59.000Z

    On the basis of the density response formalism an expression for the pseudopotential of dense semiclassical plasma, which takes account of quantum-mechanical effects, local field corrections, and electronic screening effects is obtained. The static structure factors taking into account both local fields and quantum-mechanical effects are calculated. An electrical conductivity, thermal conductivity, and viscosity of dense semiclassical plasma are studied.

  3. Optical Spectroscopic Diagnostics Of Dusty Plasma In RF Discharge

    SciTech Connect (OSTI)

    Orazbayev, S. A.; Jumagulov, M. N.; Dosbolayev, M. K.; Silamiya, M.; Ramazanov, T. S. [IETP, Al Farabi Kazakh National University, 96a, Tole bi, Almaty, 050012 (Kazakhstan); Boufendi, L. [Universite d'Orleans, 14 Rue d'Issoudun, B.P. 6744-45067 Orleans Cedex 2 (France)

    2011-11-29T23:59:59.000Z

    The parameters of the buffer plasma containing dust particles were measured by means of spectroscopic methods. The change in the emission spectrum of the buffer plasma with addition of dust was observed. It seems to relate to changing in temperature and number density of electrons due to the influence of dusts.

  4. NON-INTRUSIVE TEMPERATURE DIAGNOSTIC FOR A NON-NEUTRAL PLASMA

    E-Print Network [OSTI]

    Hart, Gus

    NON-INTRUSIVE TEMPERATURE DIAGNOSTIC FOR A NON-NEUTRAL PLASMA by Michael Takeshi Nakata A thesis, Associate Dean College of Physical and Mathematical Sciences #12;ABSTRACT NON-INTRUSIVE TEMPERATURE DIAGNOSTIC FOR A NON-NEUTRAL PLASMA M. Takeshi Nakata Department of Physics and Astronomy Master of Science

  5. Princeton University Plasma Physics Laboratory, Princeton, New Jersey. Annual report, October 1, 1990--September 30, 1991

    SciTech Connect (OSTI)

    Not Available

    1991-12-31T23:59:59.000Z

    This report discusses the following topics: Principal parameters of experimental devices; Tokamak Fusion Test Reactor; Burning Plasma Experiment; Princeton Beta Experiment-Modification; Current Drive Experiment-Upgrade; International Thermonuclear Experimental Reactor; International Collaboration; X-Ray Laser Studies; Hyperthermal Atomic Beam Source; Pure Electron Plasma Experiments; Plasma Processing: Deposition and Etching of Thin Films; Theoretical Studies; Tokamak Modeling; Engineering Department; Environment, Safety, and Health and Quality Assurance; Technology Transfer; Office of Human Resources and Administration; PPPL Patent Invention Disclosures; Office of Resource Management; Graduate Education: Plasma Physics; Graduate Education: Program in Plasma Science and Technology; and Science Education Program.

  6. SUPPRESSION OF DIELECTRONIC RECOMBINATION DUE TO FINITE DENSITY EFFECTS

    SciTech Connect (OSTI)

    Nikolic, D.; Gorczyca, T. W.; Korista, K. T. [Western Michigan University, Kalamazoo, MI (United States); Ferland, G. J. [University of Kentucky, Lexington, KY (United States); Badnell, N. R. [University of Strathclyde, Glasgow (United Kingdom)

    2013-05-01T23:59:59.000Z

    We have developed a general model for determining density-dependent effective dielectronic recombination (DR) rate coefficients in order to explore finite-density effects on the ionization balance of plasmas. Our model consists of multiplying by a suppression factor those highly-accurate total zero-density DR rate coefficients which have been produced from state-of-the-art theoretical calculations and which have been benchmarked by experiment. The suppression factor is based upon earlier detailed collision-radiative calculations which were made for a wide range of ions at various densities and temperatures, but used a simplified treatment of DR. A general suppression formula is then developed as a function of isoelectronic sequence, charge, density, and temperature. These density-dependent effective DR rate coefficients are then used in the plasma simulation code Cloudy to compute ionization balance curves for both collisionally ionized and photoionized plasmas at very low (n{sub e} = 1 cm{sup -3}) and finite (n{sub e} = 10{sup 10} cm{sup -3}) densities. We find that the denser case is significantly more ionized due to suppression of DR, warranting further studies of density effects on DR by detailed collisional-radiative calculations which utilize state-of-the-art partial DR rate coefficients. This is expected to impact the predictions of the ionization balance in denser cosmic gases such as those found in nova and supernova shells, accretion disks, and the broad emission line regions in active galactic nuclei.

  7. DESIGN AND CHARACTERIZATION OF A NOVEL ICP PLASMA TOOL FOR HIGH SPEED AND HIGH ACCURACY DRIE PROCESSING

    E-Print Network [OSTI]

    Technische Universiteit Delft

    the ion density profile across the plasma chamber in a research DRIE tool. The plasma conditions are: Ar ion density. Process chamber centre EdgeEdge 0 100 200 300 400 Sheetthickness(m) Process chamber argon ion density measured in a conventional ICP. 0 0.2 0.4 0.6 0.8 1 Process chamber centre Edge

  8. Tailoring the air plasma with a double laser pulse

    SciTech Connect (OSTI)

    Shneider, M. N.; Miles, R. B. [Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544-5263 (United States); Zheltikov, A. M. [Physics Department, International Laser Center, M. V. Lomonosov Moscow State University, Moscow 119992 (Russian Federation); Department of Physics and Astronomy, Texas A and M University, College Station, Texas 77843-4242 (United States)

    2011-06-15T23:59:59.000Z

    We present a comprehensive model of plasma dynamics that enables a detailed understanding of the ways the air plasma induced in the atmosphere in the wake of a laser-induced filament can be controlled by an additional laser pulse. Our model self-consistently integrates plasma-kinetic, Navier-Stokes, electron heat conduction, and electron-vibration energy transfer equations, serving to reveal laser-plasma interaction regimes where the plasma lifetime can be substantially increased through an efficient control over plasma temperature, as well as suppression of attachment and recombination processes. The model is used to quantify the limitations on the length of uniform laser-filament heating due to the self-defocusing of laser radiation by the radial profile of electron density. The envisaged applications include sustaining plasma guides for long-distance transmission of microwaves, standoff detection of impurities and potentially hazardous agents, as well as lightning control and protection.

  9. Passive Spectroscopic Diagnostics for Magnetically-confined Fusion Plasmas

    SciTech Connect (OSTI)

    Stratton, B. C.; Biter, M.; Hill, K. W.; Hillis, D. L.; Hogan, J. T.

    2007-07-18T23:59:59.000Z

    Spectroscopy of radiation emitted by impurities and hydrogen isotopes plays an important role in the study of magnetically-confined fusion plasmas, both in determining the effects of impurities on plasma behavior and in measurements of plasma parameters such as electron and ion temperatures and densities, particle transport, and particle influx rates. This paper reviews spectroscopic diagnostics of plasma radiation that are excited by collisional processes in the plasma, which are termed 'passive' spectroscopic diagnostics to distinguish them from 'active' spectroscopic diagnostics involving injected particle and laser beams. A brief overview of the ionization balance in hot plasmas and the relevant line and continuum radiation excitation mechanisms is given. Instrumentation in the soft X-ray, vacuum ultraviolet, ultraviolet, visible, and near-infrared regions of the spectrum is described and examples of measurements are given. Paths for further development of these measurements and issues for their implementation in a burning plasma environment are discussed.

  10. Anomalous radial transport in tokamak edge plasma

    E-Print Network [OSTI]

    Bodi, Vasudeva Raghavendra Kowsik

    2010-01-01T23:59:59.000Z

    Transport in tokamak plasma . . . . . . . . . . . . . . .Numerical simulations of tokamak plasma . . . . . . . . .of blobs in tokamak edge plasmas . . . . . . . . . . . . . .

  11. Equation for liquid density

    SciTech Connect (OSTI)

    Yaws, C.L.; Yang, H.C.; Hopper, J.R.; Cawley, W.A. (Lamar Univ., Beaumont, TX (US))

    1991-01-01T23:59:59.000Z

    Saturated liquid densities for organic chemicals are given as functions of temperature using a modified Rackett equation.

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

    E-Print Network [OSTI]

    Strathclyde, University of

    of plasma research and understanding their dynamics is cutting edge topic in physics Small instabilities

  13. High-beta plasma effects in a low-pressure helicon plasma

    SciTech Connect (OSTI)

    Corr, C. S.; Boswell, R. W. [Space Plasma, Power and Propulsion Group (SP3), Research School of Physical Science and Engineering, Australian National University, Canberra ACT 0200 (Australia)

    2007-12-15T23:59:59.000Z

    In this work, high-beta plasma effects are investigated in a low-pressure helicon plasma source attached to a large volume diffusion chamber. When operating above an input power of 900 W and a magnetic field of 30 G a narrow column of bright blue light (due to Ar II radiation) is observed along the axis of the diffusion chamber. With this blue mode, the plasma density is axially very uniform in the diffusion chamber; however, the radial profiles are not, suggesting that a large diamagnetic current might be induced. The diamagnetic behavior of the plasma has been investigated by measuring the temporal evolution of the magnetic field (B{sub z}) and the plasma kinetic pressure when operating in a pulsed discharge mode. It is found that although the electron pressure can exceed the magnetic field pressure by a factor of 2, a complete expulsion of the magnetic field from the plasma interior is not observed. In fact, under our operating conditions with magnetized ions, the maximum diamagnetism observed is {approx}2%. It is observed that the magnetic field displays the strongest change at the plasma centre, which corresponds to the maximum in the plasma kinetic pressure. These results suggest that the magnetic field diffuses into the plasma sufficiently quickly that on a long time scale only a slight perturbation of the magnetic field is ever observed.

  14. Plasma parameters and electron energy distribution functions in a magnetically focused plasma

    SciTech Connect (OSTI)

    Samuell, C. M.; Blackwell, B. D.; Howard, J.; Corr, C. S. [Plasma Research Laboratory, Research School of Physics and Engineering, Australian National University, Canberra (Australia)

    2013-03-15T23:59:59.000Z

    Spatially resolved measurements of ion density, electron temperature, floating potential, and the electron energy distribution function (EEDF) are presented for a magnetically focused plasma. The measurements identify a central plasma column displaying Maxwellian EEDFs at an electron temperature of about 5 eV indicating the presence of a significant fraction of electrons in the inelastic energy range (energies above 15 eV). It is observed that the EEDF remains Maxwellian along the axis of the discharge with an increase in density, at constant electron temperature, observed in the region of highest magnetic field strength. Both electron density and temperature decrease at the plasma radial edge. Electron temperature isotherms measured in the downstream region are found to coincide with the magnetic field lines.

  15. Plasma sweeper. [Patents

    DOE Patents [OSTI]

    Motley, R.W.; Glanz, J.

    1982-10-25T23:59:59.000Z

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

  16. How to model quantum plasmas

    E-Print Network [OSTI]

    G. Manfredi

    2005-05-01T23:59:59.000Z

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

  17. Bow shocks formed by plasma collisions in laser irradiated semi-cylindrical cavities

    E-Print Network [OSTI]

    Rocca, Jorge J.

    the axis to form a dense bright plasma focus. Later in time a long lasting bow shock is observed to develop a location near the cavity axis, where it collides forming a bright high density plasma focusBow shocks formed by plasma collisions in laser irradiated semi-cylindrical cavities Jorge Filevich

  18. LITHIUM PLASMA SOURCES FOR ACCELERATION AND FOCUSING OF ULTRA-RELATIVISTIC ELECTRON BEAMSi

    E-Print Network [OSTI]

    LITHIUM PLASMA SOURCES FOR ACCELERATION AND FOCUSING OF ULTRA-RELATIVISTIC ELECTRON BEAMSi P beam focusing (plasma lens). The Li vapor with a density in the 2Ã?1015 cm-3 range is produced in a heat to a focusing strength in excess of 6Ã?105 G/cm. A shorter section of plasma (L25 cm) can be used as an effective

  19. Simulations of the SLAC Plasma Lens Shinichi Masuda \\Lambda and Pisin Chen y

    E-Print Network [OSTI]

    between n p =n b = 0:1 and 100. The original bunch size is 3 and 5 ¯m in radius. Due to plasma focusing return current renders the plasma focusing effect suppressed when the plasma density further increases

  20. Heating peculiarities of a plasma containing multiply charged ions in a Z-pinch

    SciTech Connect (OSTI)

    Bykovskii, Y.A.; Lagoda, V.B.; Sheroziya, G.A.

    1980-03-05T23:59:59.000Z

    Starting from the assumption of compression of the plasma column to the size of the Larmor radius, which is described by an ion in the self-magnetic field of the discharge, and the Bennet relations, expressions are obtained for the temperature and linear density of the plasma. It is shown that the plasma heating results from the excitation of ion-acoustic turbulence.

  1. Note: On the measurement of plasma potential fluctuations using emissive probes

    SciTech Connect (OSTI)

    Bousselin, G., E-mail: guillaume.bousselin@ens-lyon.fr; Lemoine, N.; Cavalier, J.; Heuraux, S.; Bonhomme, G. [IJL, Université de Lorraine, CNRS (UMR 7198), 54506 Vandoeuvre (France)] [IJL, Université de Lorraine, CNRS (UMR 7198), 54506 Vandoeuvre (France)

    2014-05-15T23:59:59.000Z

    In this Note, it is pointed out that emissive probes cannot be used to directly and reliably measure plasma potential fluctuations. An experimentally validated model demonstrates indeed that the floating potential fluctuations of an emissive probe which floats at the mean plasma potential depend not only on the plasma potential fluctuations but also on electron density and temperature fluctuations.

  2. Nonlinear inertial Alfven wave in dusty plasmas

    SciTech Connect (OSTI)

    Mahmood, S. [Theoretical Plasma Physics Division, P.O. Nilore Islamabad 44000 (Pakistan); National Center for Physics, Shadra Valley, Quaid-i-Azam University Islamabad 44000 (Pakistan); Saleem, H. [National Center for Physics, Shadra Valley, Quaid-i-Azam University Islamabad 44000 (Pakistan)

    2011-11-29T23:59:59.000Z

    Solitary inertial Alfven wave in the presence of positively and negatively charged dust particles is studied. It is found that electron density dips are formed in the super Alfvenic region and wave amplitude is increased for the case of negatively charged dust particles in comparison with positively charged dust particles in electron-ion plasmas.

  3. Inductively generated streaming plasma ion source

    DOE Patents [OSTI]

    Glidden, Steven C.; Sanders, Howard D.; Greenly, John B.

    2006-07-25T23:59:59.000Z

    A novel pulsed, neutralized ion beam source is provided. The source uses pulsed inductive breakdown of neutral gas, and magnetic acceleration and control of the resulting plasma, to form a beam. The beam supplies ions for applications requiring excellent control of ion species, low remittance, high current density, and spatial uniformity.

  4. Three regimes of relativistic beam - plasma interaction

    SciTech Connect (OSTI)

    Muggli, P.; Allen, B.; Fang, Y.; Yakimenko, V.; Babzien, M.; Kusche, K.; Fedurin, M.; Vieira, J.; Martins, J.; Silva, L. [Max Planck Institute for Physics, 80805 Munich (Germany) and University of Southern California, Los Angeles, CA 90089 (United States); University of Southern California, Los Angeles, CA 90089 (United States); Brookhaven National Laboratory, Upton, NY 11973 (United States); GoLP/Instituto de Plasmas e Fusao Nuclear - Laboratorio Associado Instituto Superior Tecnico (IST), Technical University of Lisbon, Lisboa (Portugal)

    2012-12-21T23:59:59.000Z

    Three regimes of relativistic beam - plasma interaction can in principle be reached at the ATF depending on the relative transverse and longitudinal size of the electron bunch when compared to the cold plasma collisionless skin depth c?{omega}{sub pe}: the plasma wakefield accelerator (PWFA), the self-modulation instability (SMI), and the current filamentation instability (CFI) regime. In addition, by choosing the bunch density, the linear, quasi-nonlinear and non linear regime of the PWFA can be reached. In the case of the two instabilities, the bunch density determines the growth rate and therefore the occurrence or not of the instability. We briefly describe these three regimes and outline results demonstrating that all these regime have or will be reached experimentally. We also outline planned and possible follow-on experiments.

  5. Response of the plasma to the size of an anode electrode biased near the plasma potential

    SciTech Connect (OSTI)

    Barnat, E. V.; Laity, G. R. [Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States); Baalrud, S. D. [Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa 52242 (United States)

    2014-10-15T23:59:59.000Z

    As the size of a positively biased electrode increases, the nature of the interface formed between the electrode and the host plasma undergoes a transition from an electron-rich structure (electron sheath) to an intermediate structure containing both ion and electron rich regions (double layer) and ultimately forms an electron-depleted structure (ion sheath). In this study, measurements are performed to further test how the size of an electron-collecting electrode impacts the plasma discharge the electrode is immersed in. This is accomplished using a segmented disk electrode in which individual segments are individually biased to change the effective surface area of the anode. Measurements of bulk plasma parameters such as the collected current density, plasma potential, electron density, electron temperature and optical emission are made as both the size and the bias placed on the electrode are varied. Abrupt transitions in the plasma parameters resulting from changing the electrode surface area are identified in both argon and helium discharges and are compared to the interface transitions predicted by global current balance [S. D. Baalrud, N. Hershkowitz, and B. Longmier, Phys. Plasmas 14, 042109 (2007)]. While the size-dependent transitions in argon agree, the size-dependent transitions observed in helium systematically occur at lower electrode sizes than those nominally derived from prediction. The discrepancy in helium is anticipated to be caused by the finite size of the interface that increases the effective area offered to the plasma for electron loss to the electrode.

  6. Tunable Laser Plasma Accelerator based on Longitudinal Density Tailoring

    E-Print Network [OSTI]

    Gonsalves, Anthony

    2012-01-01T23:59:59.000Z

    dot line), which increases to ? 3.5 compared with the vacuum focal value of ? 1.5, producing a bubble

  7. Using Radio Waves to Control Fusion Plasma Density

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of ScienceandMesa del SolStrengthening aTurbulence mayUndergraduateAboutUserHadoop

  8. Nuclear Science

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels DataDepartment of Energy Your Density Isn'tOrigin of Contamination in ManyDepartment of Energy NorthBDepartment of83-2007Science and

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

    E-Print Network [OSTI]

    Hulbert, Dustin M.

    2008-01-01T23:59:59.000Z

    investigations on the spark plasma sintering/synthesisinvestigations on the spark plasma sintering/synthesisenhancement in spark-plasma sintering: Impact of high

  10. Electron acceleration by a circularly polarized laser pulse in a plasma K. P. Singha)

    E-Print Network [OSTI]

    Roy, Subrata

    of Physics, Indian Institute of Technology, New Delhi-110016, India Received 12 January 2004; accepted 4 May fields, and the electrons gain much higher energies. The resonance is stronger at higher values and plasma density, and initial electron energy. At higher plasma density, the group velocity of the laser

  11. Plasma Sources Sci. Technol. 5 (1996) 173180. Printed in the UK Downstream physics of the helicon

    E-Print Network [OSTI]

    Chen, Francis F.

    1996-01-01T23:59:59.000Z

    Plasma Sources Sci. Technol. 5 (1996) 173­180. Printed in the UK Downstream physics of the helicon and that a dense, cool (Te downstream region. The density n and electron densities, it plays little role in the downstream evolution of the plasma. These results indicate

  12. Recombination of He+ in a pulsed helium plasma

    E-Print Network [OSTI]

    Chang, Cheng-shu

    1967-01-01T23:59:59.000Z

    -body Recombinatior Rate Coefficient A for Helium Plasma at Pressure 5 and 6 mm Hg Calculs. ted Values of Electron Temperature Te and. 'Density Ne and the T1"ree-body Recombination Rate Coefficient A for Helium Plasma at Pressure 7 and 8 mm Hg 38 1 ?-. 1 i o.... . ! o. ' T. inc foe Hc '. ior. . 7 i, "1 2 0 i m'" Hg 7. j':lectron Vcm'ocr. . tur= T and Electron Dc!is i. ty a 'h, '" c L:i on o'* Time for Helium Plasma I! . J. r 4! i:lm ii)& ~ ~ ~ ~ ~ ~ 8. Electron Tempo. ature Te and Electron Density N as a...

  13. Princeton Plasma Physics Laboratory News

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC)IntegratedSpeedingTechnical News, information andNetarchive Princeton Plasma Physics

  14. Princeton Plasma Physics Laboratory News

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC)IntegratedSpeedingTechnical News, information andNetarchive Princeton Plasma Physics

  15. Cold atmospheric plasma in cancer therapy

    SciTech Connect (OSTI)

    Keidar, Michael; Shashurin, Alex; Volotskova, Olga [Mechanical and Aerospace Engineering, George Washington University, Washington DC 20052 (United States)] [Mechanical and Aerospace Engineering, George Washington University, Washington DC 20052 (United States); Ann Stepp, Mary [Medical School, George Washington University, Washington DC 20052 (United States)] [Medical School, George Washington University, Washington DC 20052 (United States); Srinivasan, Priya; Sandler, Anthony [Childrens National Medical Center, Washington DC 20010 (United States)] [Childrens National Medical Center, Washington DC 20010 (United States); Trink, Barry [Head and Neck Cancer Research Division, Department of Otolaryngology, School of Medicine, Johns Hopkins University, Baltimore, Maryland 21205 (United States)] [Head and Neck Cancer Research Division, Department of Otolaryngology, School of Medicine, Johns Hopkins University, Baltimore, Maryland 21205 (United States)

    2013-05-15T23:59:59.000Z

    Recent progress in atmospheric plasmas has led to the creation of cold plasmas with ion temperature close to room temperature. This paper outlines recent progress in understanding of cold plasma physics as well as application of cold atmospheric plasma (CAP) in cancer therapy. Varieties of novel plasma diagnostic techniques were developed recently in a quest to understand physics of CAP. It was established that the streamer head charge is about 10{sup 8} electrons, the electrical field in the head vicinity is about 10{sup 7} V/m, and the electron density of the streamer column is about 10{sup 19} m{sup ?3}. Both in-vitro and in-vivo studies of CAP action on cancer were performed. It was shown that the cold plasma application selectively eradicates cancer cells in-vitro without damaging normal cells and significantly reduces tumor size in-vivo. Studies indicate that the mechanism of action of cold plasma on cancer cells is related to generation of reactive oxygen species with possible induction of the apoptosis pathway. It is also shown that the cancer cells are more susceptible to the effects of CAP because a greater percentage of cells are in the S phase of the cell cycle.

  16. Large area atmospheric-pressure plasma jet

    DOE Patents [OSTI]

    Selwyn, Gary S. (Los Alamos, NM); Henins, Ivars (Los Alamos, NM); Babayan, Steve E. (Huntington Beach, CA); Hicks, Robert F. (Los Angeles, CA)

    2001-01-01T23:59:59.000Z

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

  17. Characterization of plasma expansion dynamics in a high power diode with a carbon-fiber-aluminum cathode

    SciTech Connect (OSTI)

    Ju, J.-C., E-mail: jujinchuan@126.com [College of Optoelectronic Science and Engineering, National University of Defense Technology, Changsha 410073 (China); Laboratoire de Physique des Gaz et des Plasmas, CNRS-Université Paris-Sud, Orsay 91405 (France); Liu, L.; Cai, D. [College of Optoelectronic Science and Engineering, National University of Defense Technology, Changsha 410073 (China)

    2014-06-09T23:59:59.000Z

    Thermal plasma expansion is characterised during the operation of a high power diode with an explosive emission carbon-fiber-aluminum cathode driven by a 250?kV, 150?ns accelerating pulse. It is found that a quasi-stationary state of plasma expansion is obtained during the main part of the accelerating pulse and the whole plasma expansion exhibits an “U”-shape velocity evolution. A theoretical model describing the dynamics of plasma expansion is developed, which indicates that the plasma expansion velocity is determined by equilibrium between the diode current density and plasma thermal electron current density.

  18. Submitted IEEE Trans. Plasma Science Shvets Fisch

    E-Print Network [OSTI]

    /injector charged particle bunches. Since phase equiva- lently, ####) enhanced wake be controlled the detuning initially moves with v v acceler- ated velocity larger laser group velocity. The intensity threshold becomes

  19. Science Undergraduate Laboratory Internship (SULI) | Princeton Plasma

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  20. About Science Education | Princeton Plasma Physics Lab

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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  1. IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL.

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  2. IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL.

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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  3. 2012 Science Bowls | Princeton Plasma Physics Lab

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  4. 2013 Science Bowl | Princeton Plasma Physics Lab

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  5. Surface science | Princeton Plasma Physics Lab

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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  6. Princeton Plasma Physics Lab - Science literacy

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  7. Princeton Plasma Physics Lab - Surface science

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  8. Study on the effect of target on plasma parameters of magnetron sputtering discharge plasma

    SciTech Connect (OSTI)

    Saikia, P.; Kakati, B.; Saikia, B. K. [Centre of Plasma Physics, Institute for Plasma Research, Nazirakhat, Sonapur-782 402, Kamrup, Assam (India)] [Centre of Plasma Physics, Institute for Plasma Research, Nazirakhat, Sonapur-782 402, Kamrup, Assam (India)

    2013-10-15T23:59:59.000Z

    In this study, the effect of magnetron target on different plasma parameters of Argon/Hydrogen (Ar - H{sub 2}) direct current (DC) magnetron discharge is examined. Here, Copper (Cu) and Chromium (Cr) are used as magnetron targets. The value of plasma parameters such as electron temperature (kT{sub e}), electron density (N{sub e}), ion density (N{sub i}), degree of ionization of Ar, and degree of dissociation of H{sub 2} for both the target are studied as a function of input power and hydrogen content in the discharge. The plasma parameters are determined by using Langmuir probe and Optical emission spectroscopy. On the basis of the different reactions in the gas phase, the variation of plasma parameters and sputtering rate are explained. The obtained results show that electron and ion density decline with gradual addition of Hydrogen in the discharge and increase with rising input power. It brings significant changes on the degree of ionization of Ar and dissociation of H{sub 2}. The enhanced value of electron density (N{sub e}), ion density (N{sub i}), degree of Ionization of Ar, and degree of dissociation of H{sub 2} for Cr compared to Cu target is explained on the basis of it's higher Ion Induced Secondary Electron Emission Coefficient (ISEE) value.

  9. Positron plasma control techniques for the production of cold antihydrogen

    SciTech Connect (OSTI)

    Funakoshi, R.; Hayano, R. S. [Department of Physics, University of Tokyo, Tokyo 113-0033 (Japan); Amoretti, M.; Macri, M.; Testera, G.; Variola, A. [Istituto Nazionale di Fisica Nucleare, Sezione di Genova, 16146 Genova (Italy); Bonomi, G. [Dipartimento di Ingegneria Meccanica, Universita di Brescia, 25123 Brescia (Italy); Dipartimento di Fisica Nucleare e Teorica, Universita di Pavia, 27100 Pavia (Italy); Bowe, P. D.; Hangst, J. S.; Madsen, N. [Department of Physics and Astronomy, University of Aarhus, 8000 Aarhus C (Denmark); Canali, C.; Carraro, C.; Lagomarsino, V.; Manuzio, G. [Istituto Nazionale di Fisica Nucleare, Sezione di Genova, 16146 Genova (Italy); Dipartimento di Fisica, Universita di Genova, 16146 Genova (Italy); Cesar, C. L. [Instituto de Fisica, Universidade do Brasil, Cx Postal 68528, Rio de Janeiro 21941-972 (Brazil); Charlton, M.; Joergensen, L. V.; Mitchard, D.; Werf, D. P. van der [Department of Physics, University of Wales Swansea, Swansea SA2 8PP (United Kingdom); Doser, M. [PH Department, CERN, 1211 Geneva 23 (Switzerland)] (and others)

    2007-07-15T23:59:59.000Z

    An observation of a clear dependence of antihydrogen production on positron plasma shapes is reported. For this purpose a plasma control method has been developed combining the plasma rotating-wall technique with a mode diagnostic system. With the help of real-time and nondestructive observations, the rotating-wall parameters have been optimized. The positron plasma can be manipulated into a wide range of shapes (aspect ratio 6.5{<=}{alpha} < or approx. 80) and densities (1.5x10{sup 8}{<=}n < or approx. 7x10{sup 9} cm{sup -3}) within a short duration (25 s) compatible with the ATHENA antihydrogen production cycle.

  10. Rayleigh-Taylor instability in quantum magnetized viscous plasma

    SciTech Connect (OSTI)

    Hoshoudy, G. A., E-mail: g_hoshoudy@yahoo.com [South Valley University, Department of Applied Mathematics, Faculty of Science (Egypt)

    2011-09-15T23:59:59.000Z

    Quantum effects on Rayleigh-Taylor instability of stratified viscous plasmas layer under the influence of vertical magnetic field are investigated. By linearly solving the viscous QMHD equations into normal mode, a forth-order ordinary differential equation is obtained to describe the velocity perturbation. Then the growth rate is derived for the case where a plasma with exponential density distribution is confined between two rigid planes. The results show that, the presence of vertical magnetic field beside the quantum effect will bring about more stability on the growth rate of unstable configuration for viscous plasma, which is greater than that of inviscous plasma.

  11. Linear and nonlinear wave propagation in weakly relativistic quantum plasmas

    SciTech Connect (OSTI)

    Stefan, Martin; Brodin, Gert [Department of Physics, Umea University, SE-901 87 Umea (Sweden)

    2013-01-15T23:59:59.000Z

    We consider a recently derived kinetic model for weakly relativistic quantum plasmas. We find that that the effects of spin-orbit interaction and Thomas precession may alter the linear dispersion relation for a magnetized plasma in case of high plasma densities and/or strong magnetic fields. Furthermore, the ponderomotive force induced by an electromagnetic pulse is studied for an unmagnetized plasma. It turns out that for this case the spin-orbit interaction always gives a significant contribution to the quantum part of the ponderomotive force.

  12. Time-resolved measurement of plasma parameters by means of triple probe

    SciTech Connect (OSTI)

    Qayyum, A.; Ahmad, N.; Ahmad, S.; Deeba, Farah; Ali, Rafaqat; Hussain, S. [National Tokamak Fusion Program, 3329 Islamabad (Pakistan)] [National Tokamak Fusion Program, 3329 Islamabad (Pakistan)

    2013-12-15T23:59:59.000Z

    Triple Langmuir probe (TLP) diagnostic system with its necessary driving circuit is developed and successfully applies for time-resolved measurement of plasma parameters in the negative glow region of pulsating-dc discharge. This technique allows the instantaneous measurement of electron temperature [T{sub ?}], electron number density [n{sub ?}] as well as plasma fluctuations without any voltage or frequency sweep. In TLP configuration two probes are differentially biased and serve as a floating symmetric double probe whereas the third probe is simply floating into plasma to measure floating potential as a function of time and thus incorporates the effect of plasma fluctuations. As an example of the application to time-dependent plasmas, basic plasma parameters such as floating potential, electron temperature, and electron number density in low pressure air discharge are determined as a function of time for different fill pressure. The results demonstrate temporal evolution of plasma parameters and thus plasma generation progression for different fill pressures.

  13. Dense Metal Plasma in a Solenoid for Ion Beam Neutralization

    SciTech Connect (OSTI)

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

    2010-10-30T23:59:59.000Z

    Space-charge neutralization is required to compress and focus a pulsed, high-current ion beam on a target for warm dense matter physics or heavy ion fusion experiments. We described approaches to produce dense plasma in and near the final focusing solenoid through which the ion beam travels, thereby providing an opportunity for the beam to acquire the necessary space-charge compensating electrons. Among the options are plasma injection from pulsed vacuum arc sources located outside the solenoid, and using a high current (> 4 kA) pulsed vacuum arc plasma from a ring cathode near the edge of the solenoid. The plasma distribution is characterized by photographic means, by an array of movable Langmuir probes, by a small single probe, and by evaluating Stark broadening of the Balmer H beta spectral line. In the main approach described here, the plasma is produced at several cathode spots distributed azimuthally on the ring cathode. It is shown that the plasma is essentially hollow, as determined by the structure of the magnetic field, though the plasma density exceeds 1014 cm-3 in practically all zones of the solenoid volume if the ring electrode is placed a few centimeters off the center of the solenoid. The plasma is non-uniform and fluctuating, however, since its density exceeds the ion beam density it is believed that this approach could provide a practical solution to the space charge neutralization challenge.

  14. Optical emission spectroscopy of atmospheric pressure microwave plasmas

    SciTech Connect (OSTI)

    Jia Haijun; Fujiwara, Hiroyuki; Kondo, Michio [Research Center for Photovoltaics (RCPVs), National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568 (Japan); Kuraseko, Hiroshi [Furukawa Electric Co., Ltd., Production Technology Development Center, 6 Yawata-Kaigandori, Chiba 290-8555 (Japan)

    2008-09-01T23:59:59.000Z

    The optical emission behaviors of Ar, He, and Ar+He plasmas generated in air using an atmospheric pressure microwave plasma source have been studied employing optical emission spectroscopy (OES). Emissions from various source gas species and air were observed. The variations in the intensities and intensity ratios of specific emissions as functions of the microwave power and gas flow rate were analyzed to investigate the relationship between the emission behavior and the plasma properties. We find that dependence of the emission behavior on the input microwave power is mainly determined by variations in electron density and electron temperature in the plasmas. On the other hand, under different gas flow rate conditions, changes in the density of the source gas atoms also significantly affect the emissions. Interestingly, when plasma is generated using an Ar+He mixture, emissions from excited He atoms disappear while a strong H{sub {alpha}} signal appears. The physics behind these behaviors is discussed in detail.

  15. Influence of electron injection into 27 cm audio plasma cell on the plasma diagnostics

    SciTech Connect (OSTI)

    Haleem, N. A.; Ragheb, M. S.; Zakhary, S. G. [Accelerators Department, Nuclear Research Center, AEA, Cairo 13759 (Egypt)] [Accelerators Department, Nuclear Research Center, AEA, Cairo 13759 (Egypt); El Fiki, S. A.; Nouh, S. A. [Faculty of Science, Ain Shams University, Cairo 11566 (Egypt)] [Faculty of Science, Ain Shams University, Cairo 11566 (Egypt); El Disoki, T. M. [Faculty of Girls, Ain Shams University, Cairo 11566 (Egypt)] [Faculty of Girls, Ain Shams University, Cairo 11566 (Egypt)

    2013-08-15T23:59:59.000Z

    In this article, the plasma is created in a Pyrex tube (L = 27 cm, ?= 4 cm) as a single cell, by a capacitive audio frequency (AF) discharge (f = 10–100 kHz), at a definite pressure of ?0.2 Torr. A couple of tube linear and deviating arrangements show plasma characteristic conformity. The applied AF plasma and the injection of electrons into two gas mediums Ar and N{sub 2} revealed the increase of electron density at distinct tube regions by one order to attain 10{sup 13}/cm{sup 3}. The electrons temperature and density strengths are in contrast to each other. While their distributions differ along the plasma tube length, they show a decaying sinusoidal shape where their peaks position varies by the gas type. The electrons injection moderates electron temperature and expands their density. The later highest peak holds for the N{sub 2} gas, at electrons injection it changes to hold for the Ar. The sinusoidal decaying density behavior generates electric fields depending on the gas used and independent of tube geometry. The effect of the injected electrons performs a responsive impact on electrons density not attributed to the gas discharge. Analytical tools investigate the interaction of the plasma, the discharge current, and the gas used on the electrodes. It points to the emigration of atoms from each one but for greater majority they behave to a preferred direction. Meanwhile, only in the linear regime, small percentage of atoms still moves in reverse direction. Traces of gas atoms revealed on both electrodes due to sheath regions denote lack of their participation in the discharge current. In addition, atoms travel from one electrode to the other by overcoming the sheaths regions occurring transportation of particles agglomeration from one electrode to the other. The electrons injection has contributed to increase the plasma electron density peaks. These electrons populations have raised the generated electrostatic fields assisting the elemental ions emigration to a preferred electrode direction. Regardless of plasma electrodes positions and plasma shape, ions can be departed from one electrode to deposit on the other one. In consequence, as an application the AF plasma type can enhance the metal deposition from one electrode to the other.

  16. Dust-Plasma Sheath in an Oblique Magnetic Field

    SciTech Connect (OSTI)

    Foroutan, G.; Mehdipour, H. [Physics Department, Faculty of Science, Sahand University of Technology, Tabriz (Iran, Islamic Republic of)

    2008-09-07T23:59:59.000Z

    Using numerical simulations of the multi fluid equations the structure of the magnetized sheath near a plasma boundary is studied in the presence of charged dust particles. The dependence of the electron, ion, and dust densities as well as the electrostatic potential, dust charge, and ion normal velocity, on the magnetic field strength and the edge dust number density is investigated.

  17. Diagnosis of femtosecond plasma filament by channeling microwaves along the filament

    SciTech Connect (OSTI)

    Alshershby, Mostafa; Ren, Yu; Qin, Jiang; Hao, Zuoqiang; Lin, Jingquan [School of Science, Changchun University of Science and Technology, Changchun 130022 (China)] [School of Science, Changchun University of Science and Technology, Changchun 130022 (China)

    2013-05-20T23:59:59.000Z

    We introduce a simple, fast, and non-intrusive experimental method to obtain the basic parameters of femtosecond laser-generated plasma filament. The method is based on the channeling of microwaves along both a plasma filament and a well-defined conducting wire. By comparing the detected microwaves that propagate along the plasma filament and a copper wire with known conductivity and spatial dimension, the basic parameters of the plasma filament can be easily obtained. As a result of the possibility of channeling microwave radiation along the plasma filament, we were then able to obtain the plasma density distribution along the filament length.

  18. ORIGINAL PAPER BambooFiber Filled High Density Polyethylene Composites

    E-Print Network [OSTI]

    ORIGINAL PAPER Bamboo­Fiber Filled High Density Polyethylene Composites: Effect of Coupling Springer Science+Business Media, LLC 2008 Abstract High density polyethylene (HDPE)/bamboo composites of the composites were studied. The equilibrium torque during compounding decreased with use of clay master- batch

  19. Plasma Response to Lithium-Coated Plasma-Facing Components in the National Spherical Torus Experiment

    SciTech Connect (OSTI)

    M.G. Bell, H.W. Kugel, R. Kaita, L.E. Zakharov, H. Schneider, B.P. LeBlanc, D. Mansfield, R.E. Bell, R. Maingi, S. Ding, S.M. Kaye, S.F. Paul, S.P. Gerhardt, J.M. Canik, J.C. Hosea, G. Taylor and the NSTX Research Team

    2009-08-20T23:59:59.000Z

    Experiments in the National Spherical Torus Experiment (NSTX) have shown beneficial effects on the performance of divertor plasmas as a result of applying lithium coatings on the graphite and carbonfiber- composite plasma-facing components. These coatings have mostly been applied by a pair of lithium evaporators mounted at the top of the vacuum vessel which inject collimated streams of lithium vapor towards the lower divertor. In NBI-heated, deuterium H-mode plasmas run immediately after the application of lithium, performance modifications included decreases in the plasma density, particularly in the edge, and inductive flux consumption, and increases in the electron and ion temperatures and the energy confinement time. Reductions in the number and amplitude of ELMs were observed, including complete ELM suppression for periods up to 1.2 s, apparently as a result of altering the stability of the edge. However, in the plasmas where ELMs were suppressed, there was a significant secular increase in the effective ion charge Zeff and the radiated power as a result of increases in the carbon and medium-Z metallic impurities, although not of lithium itself which remained at a very low level in the plasma core, <0.1%. The impurity buildup could be inhibited by repetitively triggering ELMs with the application of brief pulses of an n = 3 radial field perturbation. The reduction in the edge density by lithium also inhibited parasitic losses through the scrape-off layer of ICRF power coupled to the plasma, enabling the waves to heat electrons in the core of H-mode plasmas produced by NBI. Lithium has also been introduced by injecting a stream of chemically stabilized, fine lithium powder directly into the scrape-off layer of NBI-heated plasmas. The lithium was ionized in the SOL and appeared to flow along the magnetic field to the divertor plates. This method of coating produced similar effects to the evaporated lithium but at lower amounts.

  20. Density-dependent covariant energy density functionals

    SciTech Connect (OSTI)

    Lalazissis, G. A. [Physics Department, Aristotle University of Thessaloniki, GR-54124 (Greece)

    2012-10-20T23:59:59.000Z

    Relativistic nuclear energy density functionals are applied to the description of a variety of nuclear structure phenomena at and away fromstability line. Isoscalar monopole, isovector dipole and isoscalar quadrupole giant resonances are calculated using fully self-consistent relativistic quasiparticle randomphase approximation, based on the relativistic Hartree-Bogoliubovmodel. The impact of pairing correlations on the fission barriers in heavy and superheavy nuclei is examined. The role of pion in constructing desnity functionals is also investigated.

  1. Earth Sciences Environmental Earth Sciences,

    E-Print Network [OSTI]

    Brierley, Andrew

    94 Earth Sciences­ Environmental Earth Sciences, Geology Degree options MGeol (Single Honours Degrees) Earth Sciences BSc (Single Honours Degrees) Environmental Earth Sciences Geology BSc (Joint placement. * The Geology and Environmental Earth Sciences degrees are accredited by the Geological Society

  2. oxygen-plasma | EMSL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    oxygen-plasma oxygen-plasma Leads No leads are available at this time. Conversion of 1,2-Propylene Glycol on Rutile TiO2(110). Abstract: We have studied the reactions of...

  3. SCIENCE CHINA Technological Sciences

    E-Print Network [OSTI]

    Ahmad, Sajjad

    SCIENCE CHINA Technological Sciences © Science China Press and Springer-Verlag Berlin Heidelberg HU HongChang, TIAN FuQiang* & HU HePing Department of Hydraulic Engineering, State Key Laboratory as a key soil physical parameter and has been widely used to predict soil hydraulic and other related

  4. Z-Pinch Discharge in Laser Produced Plasma

    SciTech Connect (OSTI)

    Sterling, E.; Lunney, J. G. [School of Physics, Trinity College Dublin (Ireland)

    2010-10-08T23:59:59.000Z

    A fast coaxial electrical discharge, with relatively low current, was used to produce a Z-pinch effect in a laser produced aluminum plasma. The ion flux in the laser plasma was monitored with a Langmuir ion probe. The line density in the plasma column was controlled by using an aperture to select the portion of the laser plasma which enters the discharge cell. The Z-pinch dynamics were recorded using time-resolved imaging of the visible self-emission; the plasma was pinched to about one-third of the initial radius. Both the laser and Z-pinch plasmas were diagnosed using time-and space-resolved spectroscopy; substantial heating was observed. The measured behaviour of the pinch was compared with predictions of the slug model.

  5. Development of a radio frequency ion source with multi-helicon plasma injectors for neutral beam injection system of Versatile Experiment Spherical Torus

    SciTech Connect (OSTI)

    Choe, Kyumin; Jung, Bongki [Department of Nuclear Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of)] [Department of Nuclear Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of); Chung, Kyoung-Jae, E-mail: jkjlsh1@snu.ac.kr [Center for Advance Research in Fusion Reactor Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of)] [Center for Advance Research in Fusion Reactor Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of); Hwang, Y. S. [Department of Nuclear Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of) [Department of Nuclear Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of); Center for Advance Research in Fusion Reactor Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of)

    2014-02-15T23:59:59.000Z

    Despite of high plasma density, helicon plasma has not yet been applied to a large area ion source such as a driver for neutral beam injection (NBI) system due to intrinsically poor plasma uniformity in the discharge region. In this study, a radio-frequency (RF) ion source with multi-helicon plasma injectors for high plasma density with good uniformity has been designed and constructed for the NBI system of Versatile Experiment Spherical Torus at Seoul National University. The ion source consists of a rectangular plasma expansion chamber (120 × 120 × 120 mm{sup 3}), four helicon plasma injectors with annular permanent magnets and RF power system. Main feature of the source is downstream plasma confinement in the cusp magnetic field configuration which is generated by arranging polarities of permanent magnets in the helicon plasma injectors. In this paper, detailed design of the multi-helicon plasma injector and plasma characteristics of the ion source are presented.

  6. ?Linear Gas Jet with Tailored Density Profile"

    SciTech Connect (OSTI)

    KRISHNAN, Mahadevan

    2012-12-10T23:59:59.000Z

    Supersonic, highly collimated gas jets and gas-filled capillary discharge waveguides are two primary targets of choice for Laser Plasma Accelerators (LPA) . Present gas jets have lengths of only 2-4 mm at densities of 1-4E19 cm-3, sufficient for self trapping and electron acceleration to energies up to ~150 MeV. Capillary structures 3 cm long have been used to accelerate beams up to 1 GeV. Capillary discharges used in LPAs serve to guide the pump laser and optimize the energy gain. A wall-stabilized capillary discharge provides a transverse profile across the channel that helps guide the laser and combat diffraction. Gas injection via a fast nozzle at one end provides some longitudinal density control, to improve the coupling. Gas jets with uniform or controlled density profiles may be used to control electron bunch injection and are being integrated into capillary experiments to add tuning of density. The gas jet for electron injection has not yet been optimized. Our Ph-I results have provided the LPA community with an alternative path to realizing a 2-3GeV electron bunch using just a gas jet. For example, our slit/blade combination gives a 15-20mm long acceleration path with tunable density profile, serving as an alternative to a 20-mm long capillary discharge with gas injection at one end. In Ph-II, we will extend these results to longer nozzles, to see whether we can synthesize 30 or 40-mm long plasma channels for LPAs.

  7. Lower hybrid current drive at high density in Alcator C-Mod

    E-Print Network [OSTI]

    Harvey, R.W.

    Experimental observations of lower hybrid current drive (LHCD) at high density on the Alcator C-Mod tokamak are presented in this paper. Bremsstrahlung emission from relativistic fast electrons in the core plasma drops ...

  8. Direct Measurement of the Electron Density of Extended Femtosecond Laser Pulse-Induced Filaments

    SciTech Connect (OSTI)

    Chen, Y.-H.; Varma, S.; Antonsen, T. M.; Milchberg, H. M. [Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742 (United States)

    2010-11-19T23:59:59.000Z

    We present direct time- and space-resolved measurements of the electron density of femtosecond laser pulse-induced plasma filaments. The dominant nonlinearity responsible for extended atmospheric filaments is shown to be field-induced rotation of air molecules.

  9. Relativistic Bernstein waves in a degenerate plasma

    SciTech Connect (OSTI)

    Ali, Muddasir; Hussain, Azhar [Department of Physics, G.C. University, Lahore 54000 (Pakistan); Salam Chair in Physics, G.C. University, Lahore 54000 (Pakistan); Murtaza, G. [Salam Chair in Physics, G.C. University, Lahore 54000 (Pakistan)

    2011-09-15T23:59:59.000Z

    Bernstein mode for a relativistic degenerate electron plasma is investigated. Using relativistic Vlasov-Maxwell equations, a general expression for the conductivity tensor is derived and then employing Fermi-Dirac distribution function a generalized dispersion relation for the Bernstein mode is obtained. Two limiting cases, i.e., non-relativistic and ultra-relativistic are discussed. The dispersion relations obtained are also graphically presented for some specific values of the parameters depicting how the propagation characteristics of Bernstein waves as well as the Upper Hybrid oscillations are modified with the increase in plasma number density.

  10. Ion acoustic shock waves in degenerate plasmas

    SciTech Connect (OSTI)

    Akhtar, N. [Theoretical Plasma Physics Division, PINSTECH, Nilore, Islamabad 44000 Pakistan (Pakistan); Hussain, S. [Theoretical Plasma Physics Division, PINSTECH, Nilore, Islamabad 44000 Pakistan (Pakistan); Department of Physics and Applied Mathematics, PIEAS, Nilore, Islamabad 44000 Pakistan (Pakistan)

    2011-07-15T23:59:59.000Z

    Korteweg de Vries Burgers equation for negative ion degenerate dissipative plasma has been derived using reductive perturbation technique. The quantum hydrodynamic model is used to study the quantum ion acoustic shock waves. The effects of different parameters on quantum ion acoustic shock waves are studied. It is found that quantum parameter, electrons Fermi temperature, temperature of positive and negative ions, mass ratio of positive to negative ions, viscosity, and density ratio have significant impact on the shock wave structure in negative ion degenerate plasma.

  11. Terahertz radiation from a laser plasma filament

    SciTech Connect (OSTI)

    Wu, H.-C.; Meyer-ter-Vehn, J. [Max-Planck-Institut fuer Quantenoptik, D-85748 Garching (Germany); Ruhl, H. [Department fuer Physik der Ludwig-Maximillians-Universitaet, Theresienstrasse 37A, D-80333 Muenchen (Germany); Sheng, Z.-M. [Institute of Plasma Studies, Department of Physics, Shanghai Jiaotong University, Shanghai 200240 (China); Beijing National Laboratory of Condensed Matter Physics, Institute of Physics, CAS, Beijing 100190 (China)

    2011-03-15T23:59:59.000Z

    By the use of two-dimensional particle-in-cell simulations, we clarify the terahertz (THz) radiation mechanism from a plasma filament formed by an intense femtosecond laser pulse. The nonuniform plasma density of the filament leads to a net radiating current for THz radiation. This current is mainly located within the pulse and the first cycle of the wakefield. As the laser pulse propagates, a single-cycle and radially polarized THz pulse is constructively built up forward. The single-cycle shape is mainly due to radiation damping effect.

  12. Inner plasma structure of the low-latitude reconnection layer Q.-H. Zhang,1

    E-Print Network [OSTI]

    Lockwood, Mike

    and Astronautical Science, JAXA, Sagamihara, Japan. 8 School of Earth and Space Sciences, Peking University, Beijing magnetosheath magnetic field is believed to control the transport of plasma and energy from the solar wind, France. 6 Mullard Space Science Laboratory, University College London, Dorking, UK. 7 Institute of Space

  13. The FESAC Subcommittee formed to address the DOE Office of Science charge on proposed scientific user facilities invites community input in the form of short, directed white papers. The

    E-Print Network [OSTI]

    . - Context of the facility relative to the world effort in fusion and plasma science research. Describe how

  14. Explore Science

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Science Explore Science Explore Explore these Topics Activities Videos Cool Links Favorite Q&A invisible utility element Science is thinking in an organized way about things...

  15. Oscillating plasma bubbles. III. Internal electron sources and sinks

    SciTech Connect (OSTI)

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

    2012-08-15T23:59:59.000Z

    An internal electron source has been used to neutralize ions injected from an ambient plasma into a spherical grid. The resultant plasma is termed a plasma 'bubble.' When the electron supply from the filament is reduced, the sheath inside the bubble becomes unstable. The plasma potential of the bubble oscillates near but below the ion plasma frequency. Different modes of oscillations have been observed as well as a subharmonic and multiple harmonics. The frequency increases with ion density and decreases with electron density. The peak amplitude occurs for an optimum current and the instability is quenched at large electron densities. The frequency also increases if Langmuir probes inside the bubble draw electrons. Allowing electrons from the ambient plasma to enter, the bubble changes the frequency dependence on grid voltage. It is concluded that the net space charge density in the sheath determines the oscillation frequency. It is suggested that the sheath instability is caused by ion inertia in an oscillating sheath electric field which is created by ion bunching.

  16. Nesting success of the great-tailed grackle (Cassidix mexicanus prosopidicola) in relation to certain density dependent and density independent factors

    E-Print Network [OSTI]

    Gotie, Robert Francis

    1972-01-01T23:59:59.000Z

    NESTING SUCCESS OF THE GREAT-TAILED GRACKLE (CASSIDIX MEXICANUS PROSOPIDICOLA) IN RELATION TO CERTAIN DENSITY DEPENDENT AND DENSITY INDEPENDENT FACTORS A Thesis by ROBERT FRANCIS GOTIE Submitted to the Graduate College of Texas A&M University... in partial fulfillment of the requirement for the degree of MASTER OF SCIENCE December 1972 Major Subject: Wildlife Science NESTING SUCCESS OF THE GREAT-TAILED GRACKLE (CASSIDIX MEXICANUS PROSOPIDICOLA) IN RELATION TO CERTAIN DENSITY DEPENDENT...

  17. Princeton Plasma Physics Laboratory. Annual report, October 1, 1989--September 30, 1990

    SciTech Connect (OSTI)

    Not Available

    1990-12-31T23:59:59.000Z

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

  18. 131Cognitive Science COGNITIVE SCIENCE

    E-Print Network [OSTI]

    Marsh, David

    131Cognitive Science COGNITIVE SCIENCE PROFESSOR ELMES* MAJOR A major in cognitive science leading courses: Cognitive Science 110, 395, 403, 473; Computer Science 111, 211; Philosophy 106, 313; Psychology Science: Com- puter Science 295 (LISP, PROLOG or C), 313, 315; Psychology 207 b. Philosophical Foundations

  19. Effect of strongly coupled plasma on photoionization cross section

    SciTech Connect (OSTI)

    Das, Madhusmita, E-mail: msdas@barc.gov.in [Department of Physics, Indian Institute of Technology, Powai, Mumbai 400076, India and Theoretical Physics Division, Bhabha Atomic Research Center, Mumbai 400085 (India)] [Department of Physics, Indian Institute of Technology, Powai, Mumbai 400076, India and Theoretical Physics Division, Bhabha Atomic Research Center, Mumbai 400085 (India)

    2014-01-15T23:59:59.000Z

    The effect of strongly coupled plasma on the ground state photoionization cross section is studied. In the non relativistic dipole approximation, cross section is evaluated from bound-free transition matrix element. The bound and free state wave functions are obtained by solving the radial Schrodinger equation with appropriate plasma potential. We have used ion sphere potential (ISP) to incorporate the plasma effects in atomic structure calculation. This potential includes the effect of static plasma screening on nuclear charge as well as the effect of confinement due to the neighbouring ions. With ISP, the radial equation is solved using Shooting method approach for hydrogen like ions (Li{sup +2}, C{sup +5}, Al{sup +12}) and lithium like ions (C{sup +3}, O{sup +5}). The effect of strong screening and confinement is manifested as confinement resonances near the ionization threshold for both kinds of ions. The confinement resonances are very much dependent on the edge of the confining potential and die out as the plasma density is increased. Plasma effect also results in appearance of Cooper minimum in lithium like ions, which was not present in case of free lithium like ions. With increasing density the position of Cooper minimum shifts towards higher photoelectron energy. The same behaviour is also true for weakly coupled plasma where plasma effect is modelled by Debye-Huckel potential.

  20. Tungsten spectroscopy relevant to the diagnostics development of ITER divertor plasmas

    SciTech Connect (OSTI)

    Clementson, J; Beiersdorfer, P; Magee, E W; McLean, H S; Wood, R D

    2009-12-01T23:59:59.000Z

    The ITER tokamak will have tungsten divertor tiles and, consequently, the divertor plasmas are expected to contain tungsten ions. The spectral emission from these ions can serve to diagnose the divertor for plasma parameters such as tungsten concentrations, densities, ion and electron temperatures, and flow velocities. The ITER divertor plasmas will likely have densities around 10{sup 14-15} cm{sup -3} and temperatures below 150 eV. These conditions are similar to the plasmas at the Sustained Spheromak Physics Experiment (SSPX) in Livermore. To simulate ITER divertor plasmas, a tungsten impurity was introduced into the SSPX spheromak by prefilling it with tungsten hexacarbonyl prior to the usual hydrogen gas injection and initiation of the plasma discharge. The possibility of using the emission from low charge state tungsten ions to diagnose tokamak divertor plasmas has been investigated using a high-resolution extreme ultraviolet spectrometer.

  1. Dynamic polarizability of an atomic ion within a dense plasma

    SciTech Connect (OSTI)

    Basu, Joyee; Ray, Debasis [Department of Physics, Bengal Engineering and Science University, Shibpur, Howrah 711 103, West Bengal (India)

    2011-01-15T23:59:59.000Z

    We analyze the influence of plasma electron density on frequency-dependent linear field-response behavior of an atomic ion embedded in a dense plasma medium. The frequency-dependent atomic response, characterized by the dynamic dipole polarizability {alpha}{sub d}({omega}) as a function of the angular frequency {omega} of the time-dependent field, is estimated here up to the first pole of {alpha}{sub d}({omega}) on the {omega} axis (corresponding to the lowest resonance transition 1s{sup 2} {sup 1}S{yields}1s2p {sup 1}P) for the ground state 1s{sup 2} {sup 1}S of a two-electron atomic ion Ne{sup 8+} (Z = 10) at different plasma electron densities, as a typical example, employing the time-dependent coupled Hartree-Fock scheme within the framework of the ion-sphere model. It is observed that, owing to plasma density-induced enhancement of {alpha}{sub d}({omega}) at every {omega}, the pole position of {alpha}{sub d}({omega}) on the {omega} axis retracts toward the origin. This indicates a density-induced lowering (redshift) of the corresponding transition energy that conforms to experimentally observed trends. The polarizability calculation suggests a density-induced drop in the 1s{sup 2} {sup 1}S{yields}1s2p {sup 1}P absorption oscillator strength in the atomic ion within dense plasmas.

  2. Large ELMs Triggered by MHD in JET Advanced Tokamak Plasmas: Impact on Plasmas Profiles, Plasmas Facing Components and Heating Systems

    E-Print Network [OSTI]

    Large ELMs Triggered by MHD in JET Advanced Tokamak Plasmas: Impact on Plasmas Profiles, Plasmas Facing Components and Heating Systems

  3. Current density fluctuations and ambipolarity of transport

    SciTech Connect (OSTI)

    Shen, W.; Dexter, R.N.; Prager, S.C.

    1991-10-01T23:59:59.000Z

    The fluctuation in the plasma current density is measured in the MIST reversed field pinch experiment. Such fluctuations, and the measured radial profile of the k spectrum of magnetic fluctuations, supports the view and that low frequency fluctuations (f < 30 kHz) are tearing modes and high frequency fluctuations (30 kHz < f < 250 kHz) are localized turbulence in resonance with the local equilibrium magnetic field (i.e., k {center dot} B = 0). Correlation of current density and magnetic fluctuations (< {tilde j}{parallel}{tilde B}{sub r} >) demonstrates that radial particle transport from particle motion parallel to a fluctuating magnetic field is ambipolar over the full frequency range.

  4. Current density fluctuations and ambipolarity of transport

    SciTech Connect (OSTI)

    Shen, W.; Dexter, R.N.; Prager, S.C.

    1991-10-01T23:59:59.000Z

    The fluctuation in the plasma current density is measured in the MIST reversed field pinch experiment. Such fluctuations, and the measured radial profile of the k spectrum of magnetic fluctuations, supports the view and that low frequency fluctuations (f < 30 kHz) are tearing modes and high frequency fluctuations (30 kHz < f < 250 kHz) are localized turbulence in resonance with the local equilibrium magnetic field (i.e., k {center_dot} B = 0). Correlation of current density and magnetic fluctuations (< {tilde j}{parallel}{tilde B}{sub r} >) demonstrates that radial particle transport from particle motion parallel to a fluctuating magnetic field is ambipolar over the full frequency range.

  5. Global coherence of dust density waves

    SciTech Connect (OSTI)

    Killer, Carsten; Melzer, André [Institut für Physik, Ernst-Moritz-Arndt-Universität Greifswald, 17489 Greifswald (Germany)

    2014-06-15T23:59:59.000Z

    The coherence of self-excited three-dimensional dust density waves has been experimentally investigated by comparing global and local wave properties. For that purpose, three-dimensional dust clouds have been confined in a radio frequency plasma with thermophoretic levitation. Global wave properties have been measured from the line-of-sight integrated dust density obtained from homogenous light extinction measurements. Local wave properties have been obtained from thin, two-dimensional illuminated laser slices of the cloud. By correlating the simultaneous global and local wave properties, the spatial coherence of the waves has been determined. We find that linear waves with small amplitudes tend to be fragmented, featuring an incoherent wave field. Strongly non-linear waves with large amplitudes, however, feature a strong spatial coherence throughout the dust cloud, indicating a high level of synchronization.

  6. The plasma focus as a thruster

    E-Print Network [OSTI]

    Hardy, Richard Lee

    2005-02-17T23:59:59.000Z

    for the degree of MASTER OF SCIENCE Approved as to style and content by: _____________________ Bruce Freeman (Chair of Committee) _____________________ Wayne Saslow (Member) _____________________ James Rock (Member... of the coaxial geometry is the outer electrode counteracts the magnetic field produced by the center electrode, resulting in minimal magnetic field outside the electrode system. Figure 2.1 shows a simplified schematic of the plasma focus, and Figure 2.2 is a...

  7. Kinetics of complex plasma with liquid droplets

    SciTech Connect (OSTI)

    Misra, Shikha; Sodha, M. S. [Centre of Energy Studies, Indian Institute of Technology Delhi (IITD), New Delhi 110016 (India)] [Centre of Energy Studies, Indian Institute of Technology Delhi (IITD), New Delhi 110016 (India); Mishra, S. K. [Institute for Plasma Research (IPR), Gandhinagar 382428 (India)] [Institute for Plasma Research (IPR), Gandhinagar 382428 (India)

    2013-12-15T23:59:59.000Z

    This paper provides a theoretical basis for the reduction of electron density by spray of water (or other liquids) in hot plasma. This phenomenon has been observed in a hypersonic flight experiment for relief of radio black out, caused by high ionization in the plasma sheath of a hypersonic vehicle, re-entering the atmosphere. The analysis incorporates a rather little known phenomenon for de-charging of the droplets, viz., evaporation of ions from the surface and includes the charge balance on the droplets and number cum energy balance of electrons, ions, and neutral molecules; the energy balance of the evaporating droplets has also been taken into account. The analysis has been applied to a realistic situation and the transient variations of the charge and radius of water droplets, and other plasma parameters have been obtained and discussed. The analysis through made in the context of water droplets is applicable to all liquids.

  8. Geomagnetic equatorial anomaly in zonal plasma flow

    SciTech Connect (OSTI)

    Aggson, T.L.; Herrero, F.A.; Mayr, H.G.; Brace, L.H. (NASA Goddard Space Flight Center, Greenbelt, MD (United States)); Maynard, N.C. (Air Force Geophysics, Hanscom AFB, MA (United States)); Liebrecht, M.C. (Science Applications Research, Inc., Lanham, MD (United States))

    1987-01-01T23:59:59.000Z

    The authors report here on the observation of a geomagnetic signature in the zonal eastward plasma flow, which is a striking feature of the equatorial ionosphere in the evening quadrant. These observations were derived from (E {times} B)/B{sup 2} measurements made with the cylindrical double floating probe experiment carried on the Dynamics Explorer 2 (DE 2) satellite. The signature consists of a crest-trough-crest effect in the latitude dependence of the eastward plasma flow with the crests at {plus minus}8{degree} dip latitude and the trough nearly centered at the dip equator at all geographic longitudes. This phenomenon can be readioly interpreted in terms of the altitude dependence of the F region dynamo electric field, and it is related to dip equator signatures in the plasma density and the magnetic declinatoin which have been reported earlier.

  9. This article has been accepted for inclusion in a future issue of this journal. Content is final as presented, with the exception of pagination. IEEE TRANSACTIONS ON PLASMA SCIENCE 1

    E-Print Network [OSTI]

    Roy, Subrata

    , a feedback mechanism is used to handle load variation. This is achieved through the characterization power consumption at the same time is critical. The design and implementation of the complete battery presents a design of portable electronics that can generate DBD plasma with battery operation. In general

  10. PRIMARY TESTS OF LASER / E BEAM INTERACTION IN A PLASMA CHANNEL.

    SciTech Connect (OSTI)

    POGORELSKY,I.V.; BEN ZVI,I.; HIROSE,T.; YAKIMENKO,V.; KUSCHE,K.; SIDDONS,P.; ET AL

    2002-06-23T23:59:59.000Z

    A high-energy CO{sub 2} laser is channeled in a capillary discharge. Plasma dynamic simulations confirm occurrence of guiding conditions at the relatively low axial plasma density 1 {divided_by} 4 x 10{sup 17} cm{sup -3}. A relativistic electron beam transmitted through the capillary changes its properties depending upon the plasma density. We observe focusing, defocusing or steering of the e-beam. Counter-propagation of the electron and laser beams in the plasma channel results in generation of intense picosecond x-ray pulses.

  11. Precise energy eigenvalues of hydrogen-like ion moving in quantum plasmas

    E-Print Network [OSTI]

    Dutta, S; Mukherjee, T K

    2014-01-01T23:59:59.000Z

    The analytic form of the electrostatic potential felt by a slowly moving test charge in quantum plasma is being derived. It has been shown that the potential composed of two parts: Debye-Huckel screening term and near-field wake potential which depends on the velocity of the test charge and the number density of the plasma electrons. Rayleigh-Ritz variational calculation has been done to estimate precise energy eigenvalues of hydrogen-like ion under such plasma environment. A detailed analysis shows that the energy levels are gradually moves to the continuum with increasing plasma electron density while level crossing phenomenon have been observed with the variation of ion velocity.

  12. Method and apparatus for upshifting light frequency by rapid plasma creation

    DOE Patents [OSTI]

    Dawson, John M. (Pacific Palisades, CA); Wilks, Scott C. (Santa Monica, CA); Mori, Warren B. (Hermosa Beach, CA); Joshi, Chandrasekhar J. (Santa Monica, CA); Sessler, Andrew M. (Oakland, CA)

    1990-01-01T23:59:59.000Z

    Photons of an electromagnetic source wave are frequency-upshifted as a plasma is rapidly created around the path of this propagating source wave. The final frequency can be controlled by adjusting the gas density. A controlled time-varying frequency (chirped) pulse can be produced by using a controlled spatially varying gas density. The plasma must be created in a time which is short compared to the transit time of the light through the plasmas region. For very fast creation over one to at most a few light periods of an overdense plasma, static magnetic fields with short wavelengths are created.

  13. A new low-frequency backward mode in inhomogeneous plasmas

    SciTech Connect (OSTI)

    Vranjes, J., E-mail: jvranjes@yahoo.com [Institute of Physics, Pregrevica 118, 11080 Zemun, Belgrade (Serbia)

    2014-07-15T23:59:59.000Z

    When an electromagnetic transverse wave propagates through an inhomogeneous plasma so that its electric field has a component in the direction of the background density gradient, there appears a disbalance of charge in every plasma layer, caused by the density gradient. Due to this, some additional longitudinal electric field component appears in the direction of the wave vector. This longitudinal field may couple with the usual electrostatic longitudinal perturbations like the ion acoustic, electron Langmuir, and ion plasma waves. As a result, these standard electrostatic waves are modified and in addition to this a completely new low-frequency mode appears. Some basic features of the coupling and modification of the ion acoustic wave, and properties of the new mode are discussed here, in ordinary electron-ion and in pair plasmas.

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

    SciTech Connect (OSTI)

    Zhang, Lin; Ouyang, Ji-Ting, E-mail: jtouyang@bit.edu.cn [School of Physics, Beijing Institute of Technology, Beijing 100081 (China)

    2014-10-15T23:59:59.000Z

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

  15. Electromagnetic solitary pulses in a magnetized electron-positron plasma

    SciTech Connect (OSTI)

    Shukla, P. K. [RUB International Chair, International Centre for Advanced Studies in Physical Sciences, Fakultaet fuer Physik und Astronomie, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany); Eliasson, B. [Institut fuer Theoretische Physik, Fakultaet fuer Physik und Astronomie, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany); Stenflo, L. [Department of Physics, Linkoeping University, SE-58183 Linkoeping (Sweden)

    2011-03-15T23:59:59.000Z

    A theory for large amplitude compressional electromagnetic solitary pulses in a magnetized electron-positron (e-p) plasma is presented. The pulses, which propagate perpendicular to the external magnetic field, are associated with the compression of the plasma density and the wave magnetic field. Here the solitary wave magnetic field pressure provides the restoring force, while the inertia comes from the equal mass electrons and positrons. The solitary pulses are formed due to a balance between the compressional wave dispersion arising from the curl of the inertial forces in Faraday's law and the nonlinearities associated with the divergence of the electron and positron fluxes, the nonlinear Lorentz forces, the advection of the e-p fluids, and the nonlinear plasma current densities. The compressional solitary pulses can exist in a well-defined speed range above the Alfven speed. They can be associated with localized electromagnetic field excitations in magnetized laboratory and space plasmas composed of electrons and positrons.

  16. Fusion Nuclear Science Facility (FNSF)

    E-Print Network [OSTI]

    Fusion Nuclear Science Facility (FNSF) ­ Motivation, Role, Required Capabilities YK Martin Peng;1 Managed by UT-Battelle for the Department of Energy Example: fusion nuclear-nonnuclear coupling effects-composites; Nano-structure alloy; PFC designs, etc. · Nuclear-nonnuclear coupling in PFC: - Plasma ion flux induces

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

    E-Print Network [OSTI]

    Martin, Jan M.L.

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

  18. Comparison of various interpretation methods of the electric probe measurements in inductively coupled Ar and O{sub 2} plasmas

    SciTech Connect (OSTI)

    Woo Seo, Min; Keun Bae, Min; Chung, T. H., E-mail: thchung@dau.ac.kr [Department of Physics, Dong-A University, Busan 604-714 (Korea, Republic of)

    2014-02-15T23:59:59.000Z

    In low-pressure inductively coupled argon and oxygen discharges, the plasma density and electron temperature and the electron energy distribution function (EEDF) were obtained by using a cylindrical electric probe. The plasma densities were determined by various methods to interpret the probe current-voltage characteristic curve: the EEDF integration, the electron saturation current, the ion current at the floating potential, and the orbital-motion-limited (OML) ion current. Quite a good agreement exists between the plasma densities determined by various classical methods. Although the probe technique has some limitation in electronegative plasmas, the plasma densities determined from OML theory compare well with those measured by the ion saturation current at the floating potential in the oxygen discharges. In addition, the EEDFs of inductively coupled Ar and oxygen plasmas are observed to be nearly Maxwellian at the pressure range of 1-40 mTorr.

  19. High density matter

    E-Print Network [OSTI]

    J. R. Stone

    2013-02-11T23:59:59.000Z

    The microscopic composition and properties of matter at super-saturation densities have been the subject of intense investigation for decades. The scarcity of experimental and observational data has lead to the necessary reliance on theoretical models. However, there remains great uncertainty in these models, which, of necessity, have to go beyond the over-simple assumption that high density matter consists only of nucleons and leptons. Heavy strange baryons, mesons and quark matter in different forms and phases have to be included to fulfil basic requirements of fundamental laws of physics. In this review the latest developments in construction of the Equation of State (EoS) of high-density matter at zero and finite temperature assuming different composition of the matter are surveyed. Critical comparison of model EoS with available observational data on neutron stars, including gravitational masses, radii and cooling patterns is presented. The effect of changing rotational frequency on the composition of neutron stars during their lifetime is demonstrated. Compatibility of EoS of high-density, low temperature compact objects and low density, high temperature matter created in heavy-ion collisions is discussed.

  20. Virtual Laboratory for Technology For Fusion Energy Science

    E-Print Network [OSTI]

    VLT Virtual Laboratory for Technology For Fusion Energy Science Stan Milora, ORNL Director, Virtual and ITER #12;VLT Virtual Laboratory for Technology For Fusion Energy Science The Technology Program Virtual Laboratory for Technology For Fusion Energy Science The VLT is the steward of burning plasma