National Library of Energy BETA

Sample records for density laboratory plasmas

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

    National Nuclear Security Administration (NNSA)

    Jobs Apply for Our Jobs Our Jobs Working at NNSA Blog Home High Energy Density Laboratory Plasmas Program High Energy Density Laboratory Plasmas Program NNSA invests in next ...

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

    National Nuclear Security Administration (NNSA)

    Administration | (NNSA) High Energy Density Laboratory Plasmas Program Steady advances in increasing the energy, power, and brightness of lasers and particle beams and advances in pulsed power systems have made possible the exploration of matter at extremely high energy density in the laboratory. Exciting new experimental regimes are being realized by exploiting the scientific capabilities of existing ICF Office facilities, as well as the relevant Department of Defense (DoD) and university

  3. High Energy Density Laboratory Plasmas | National Nuclear Security

    National Nuclear Security Administration (NNSA)

    Administration | (NNSA) High Energy Density Laboratory Plasmas NNSA's Office of Inertial Confinement Fusion and DOE's Office of Science established a joint program in HEDLP in 2008. Initially, this program was a combination of work that was funded as part of the NNSA's Stewardship Science Academic Alliances Program in the research area of high energy density physics and the DOE Office of Science's HEDLP Program and Innovative Confinement Concepts Program. Steady advances in increasing the

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

    National Nuclear Security Administration (NNSA)

    selected embody the breadth of research in HEDLP science, ranging from the study of magnetized astrophysical jets to large-scale simulation of kinetic laser plasma interactions.

  5. Research Opportunities in High Energy Density Laboratory Plasmas on the NDCX-II Facility

    SciTech Connect (OSTI)

    Barnard, John; Cohen, Ron; Friedman, Alex; Grote, Dave; Lund, Steven; Sharp, Bill; Bieniosek, Frank; Ni, Pavel; Roy, Prabir; Henestroza, Enrique; Jung, Jin-Young; Kwan, Joe; Lee, Ed; Leitner, Matthaeus; Lidia, Steven; Logan, Grant; Seidl, Peter; Vay, Jean-Luc; Waldron, Will

    2009-03-23

    Intense beams of heavy ions offer a very attractive tool for fundamental research in high energy density physics and inertial fusion energy science. These applications build on the significant recent advances in the generation, compression and focusing of intense heavy ion beams in the presence of a neutralizing background plasma. Such beams can provide uniform volumetric heating of the target during a time-scale shorter than the hydrodynamic response time, thereby enabling a significant suite of experiments that will elucidate the underlying physics of dense, strongly-coupled plasma states, which have been heretofore poorly understood and inadequately diagnosed, particularly in the warm dense matter regime. The innovations, fundamental knowledge, and experimental capabilities developed in this basic research program is also expected to provide new research opportunities to study the physics of directly-driven ion targets, which can dramatically reduce the size of heavy ion beam drivers for inertial fusion energy applications. Experiments examining the behavior of thin target foils heated to the warm dense matter regime began at the Lawrence Berkeley National Laboratory in 2008, using the Neutralized Drift Compression Experiment - I (NDCX-I) facility, and its associated target chamber and diagnostics. The upgrade of this facility, called NDCX-II, will enable an exciting set of scientific experiments that require highly uniform heating of the target, using Li{sup +} ions which enter the target with kinetic energy in the range of 3 MeV, slightly above the Bragg peak for energy deposition, and exit with energies slightly below the Bragg peak. This document briefly summarizes the wide range of fundamental scientific experiments that can be carried out on the NDCX-II facility, pertaining to the two charges presented to the 2008 Fusion Energy Science Advisory Committee (FESAC) panel on High Energy Density Laboratory Plasmas (HEDLP). These charges include: (1) Identify

  6. 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; Mase, Atsushi; Nishida, Yasushi; Cheng, C. Z.

    2014-02-15

    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.

  7. Princeton Plasma Physics Laboratory

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

    Plasma Physics Laboratory P.O. Box 451 Princeton, NJ 08543-0451 GPS: 100 Stellarator Road Princeton, NJ 08540 www.pppl.gov 2016 Princeton Plasma Physics Laboratory. A ...

  8. Princeton Plasma Physics Laboratory

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

    Plasma Physics Laboratory P.O. Box 451 Princeton, NJ 08543-0451 GPS: 100 Stellarator Road Princeton, NJ 08540 www.pppl.gov 2015 Princeton Plasma Physics Laboratory. A...

  9. Princeton Plasma Physics Laboratory

    SciTech Connect (OSTI)

    Not Available

    1990-01-01

    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.

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

    SciTech Connect (OSTI)

    Shvets, Gennady

    2014-05-09

    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 beams current, while the filaments radius is shown to be smaller than the collisionless skin depth in the plasma and primarily determined by the beams initial size. The model also accurately predicts the repartitioning ratio of the initial energy of the beams 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 beams 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 beams 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.

  11. Princeton Plasma Physics Laboratory:

    SciTech Connect (OSTI)

    Phillips, C.A.

    1986-01-01

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

  12. Princeton Plasma Physics Laboratory News

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

    archive Princeton Plasma Physics Laboratory news feed en PPPL physicists simulate innovative method for starting up tokamaks without...

  13. High-Energy-Density Plasmas, Fluids

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

    High-Energy-Density Plasmas, Fluids High-Energy-Density Plasmas, Fluids National security depends on science and technology. The United States relies on Los Alamos National Laboratory for the best of both. No place on Earth pursues a broader array of world-class scientific endeavors. TRIDENT target chamber Sasi Palaniyappan, right, and Rahul Shah left inside a target chamber where the TRIDENT short pulse laser is aimed at a very thin diamond- foil target, a fraction of a micrometer thick. The

  14. Plasma digital density determining device

    DOE Patents [OSTI]

    Sprott, Julien C.; Lovell, Thomas W.; Holly, Donald J.

    1976-01-01

    The density of a decaying plasma in an electrically conducting enclosure is determined by applying an excitation to the cavity formed by the enclosure and counting digitally the number of resonant frequencies traversed by the combination of the cavity and the decaying plasma.

  15. Princeton Plasma Physics Laboratory

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

    generations. The Laboratory, managed by Princeton University, has a more-than 60-year history of discovery and leadership in the field of fusion energy. PPPL researchers are...

  16. Princeton Plasma Physics Laboratory achieves milestone, completing...

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

    Princeton Plasma Physics Laboratory achieves milestone, completing first part of heart of ... Engineers and technicians at the U.S. Department of Energy's Princeton Plasma Physics ...

  17. Princeton Plasma Physics Laboratory Honors Three Researchers...

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

    Princeton Plasma Physics Laboratory Honors Three Researchers March 12, 2012 Tweet Widget ... received the Kaul Prize for Excellence in Plasma Physics Research and Technology ...

  18. Princeton Plasma Physics Laboratory Technology Marketing Summaries...

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

    Princeton Plasma Physics Laboratory Technology Marketing Summaries Here you'll find marketing summaries for technologies available for licensing from the Princeton Plasma Physics ...

  19. Screening potential in high density plasmas

    SciTech Connect (OSTI)

    Amari, M.; Arranz, J. P.; Butaux, J.; Nguyen, H.

    1997-01-05

    On the basis of a two-ion center model, an accurate closed form of the screening potential is suggested for intermediate and high density plasmas.

  20. Plasma density diagnostic for capillary-discharge based plasma...

    Office of Scientific and Technical Information (OSTI)

    Plasma density diagnostic for capillary-discharge based plasma channels Authors: Daniels, J. 1 Search SciTech Connect for author "Daniels, J." Search SciTech Connect for...

  1. Basic Research Needs for High Energy Density Laboratory Physics

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

    National Laboratory. Basic Research Needs for High Energy Density Laboratory Physics Report of the Workshop on High Energy Density Laboratory Physics Research Needs November ...

  2. [The mission of Princeton Plasma Physics Laboratory

    SciTech Connect (OSTI)

    Not Available

    1993-03-01

    This report discusses the following about Princeton Plasma Physics Laboratory: its mission; requirements and guidance documents for the QA program; architecture; assessment organization; and specific management issues.

  3. [The mission of Princeton Plasma Physics Laboratory

    SciTech Connect (OSTI)

    Not Available

    1993-01-01

    This report discusses the following about Princeton Plasma Physics Laboratory: its mission; requirements and guidance documents for the QA program; architecture; assessment organization; and specific management issues.

  4. 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 ...

  5. DOE Princeton Plasma Physics Laboratory Purchase Power Agreement...

    Broader source: Energy.gov (indexed) [DOE]

    for proposal issued by DLA Energy on behalf of Princeton Plasma Physics Laboratory. Download the DOE Princeton Plasma Physics Laboratory purchase power agreement request for ...

  6. Top-5 Achievements at the Princeton Plasma Physics Laboratory...

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

    Top-5 Achievements at the Princeton Plasma Physics Laboratory in 2015 By John Greenwald ... the U.S. Department of Energy's Princeton Plasma Physics Laboratory advanced the ...

  7. Science Undergraduate Laboratory Internship (SULI) | Princeton Plasma

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

    Physics Lab Science Undergraduate Laboratory Internship (SULI) The Science Undergraduate Laboratory Internship (SULI) program at PPPL is for undergraduates interested in performing plasma physics and fusion energy research. Students perform research, under the guidance of laboratory staff scientists or engineers, on projects supporting PPPL's research. **The PPPL 2017 SULI program dates are June 12-August 18, 2017.** Applications for the SULI program are solicited annually for three separate

  8. Exploration of Plasma Jets Approach to High Energy Density Physics. Final report

    SciTech Connect (OSTI)

    Chen, Chiping

    2013-08-26

    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.

  9. High energy density Z-pinch plasmas using flow stabilization

    SciTech Connect (OSTI)

    Shumlak, U. Golingo, R. P. Nelson, B. A. Bowers, C. A. Doty, S. A. Forbes, E. G. Hughes, M. C. Kim, B. Knecht, S. D. Lambert, K. K. Lowrie, W. Ross, M. P. Weed, J. R.

    2014-12-15

    scaling analyses will be presented. In addition to studying fundamental plasma science and high energy density physics, the ZaP and ZaP-HD experiments can be applied to laboratory astrophysics.

  10. Interferometer for the measurement of plasma density

    DOE Patents [OSTI]

    Jacobson, Abram R.

    1980-01-01

    An interferometer which combines the advantages of a coupled cavity interferometer requiring alignment of only one light beam, and a quadrature interferometer which has the ability to track multi-fringe phase excursions unambiguously. The device utilizes a Bragg cell for generating a signal which is electronically analyzed to unambiguously determine phase modulation which is proportional to the path integral of the plasma density.

  11. Laser-Plasma Interactions in High-Energy-Density Plasmas

    SciTech Connect (OSTI)

    Baldis, H

    2006-10-17

    High temperature hohlraums (HTH) are designed to reach high radiation temperatures by coupling a maximum amount of laser energy into a small target in a short time. These 400-800 {micro}m diameter gold cylinders rapidly fill with hot plasma during irradiation with multiple beams in 1ns laser pulses. The high-Z plasmas are dense, (electron density, n{sub e}/n{sub c} {approx} 0.1-0.4), hot (electron temperature, T{sub e} {approx} 10keV) and are bathed in a high-temperature radiation field (radiation temperature, T{sub rad} {approx} 300eV). Here n{sub c}, the critical density, equals 9 x 10{sup 21}/cm{sup 3}. The laser beams heating this plasma are intense ({approx} 10{sup 15} - 10{sup 17} W/cm{sup 2}). The coupling of the laser to the plasma is a rich regime for Laser-Plasma Interaction (LPI) physics. The LPI mechanisms in this study include beam deflection and forward scattering. In order to understand the LPI mechanisms, the plasma parameters must be known. An L-band spectrometer is used to measure the and electron temperature. A ride-along experiment is to develop the x-radiation emitted by the thin back wall of the half-hohlraum into a thermal radiation source.

  12. 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

    2007-03-19

    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.

  13. Particle Gas Target for High Density Laser Produced Plasmas Charles...

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

    Particle Gas Target for High Density Laser Produced Plasmas Charles H. Skinner, Nathaniel Fisch, and Ernest Valeo This invention is a novel "particle gas" cell for achieving plasma ...

  14. At Princeton Plasma Physics Laboratory, buying small is a big...

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

    At Princeton Plasma Physics Laboratory, buying small is a big win By Gale Scott May 23, ... When scientists at the U.S. Department of Energy's Princeton Plasma Physics Laboratory ...

  15. Secretary Steven Chu Visits Princeton Plasma Physics Laboratory |

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Department of Energy Visits Princeton Plasma Physics Laboratory Secretary Steven Chu Visits Princeton Plasma Physics Laboratory September 28, 2010 - 10:34am Addthis Secretary Steven Chu Visits Princeton Plasma Physics Laboratory Elizabeth Meckes Elizabeth Meckes Director of User Experience & Digital Technologies, Office of Public Affairs Yesterday, Secretary Chu had the opportunity to visit the Department's Princeton Plasma Physics Laboratory (PPPL) in New Jersey - a facility he said has

  16. DOE Princeton Plasma Physics Laboratory Purchase Power Agreement Request

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    for Proposal | Department of Energy Princeton Plasma Physics Laboratory Purchase Power Agreement Request for Proposal DOE Princeton Plasma Physics Laboratory Purchase Power Agreement Request for Proposal Document shows a purchase power agreement (PPA) request for proposal issued by DLA Energy on behalf of Princeton Plasma Physics Laboratory. Download the DOE Princeton Plasma Physics Laboratory purchase power agreement request for proposal. (348.79 KB) More Documents & Publications

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

    SciTech Connect (OSTI)

    Bhattacharjee, Amitava

    2012-02-16

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

  18. Internal field, density & temperature measurements in MTF plasmas...

    Office of Scientific and Technical Information (OSTI)

    Title: Internal field, density & temperature measurements in MTF plasmas using Pulsed Polarimetry final report Authors: Smith, Roger J. Publication Date: 2014-08-11 OSTI ...

  19. Practicality of magnetic compression for plasma density control...

    Office of Scientific and Technical Information (OSTI)

    control Citation Details In-Document Search This content will become publicly available on March 16, 2017 Title: Practicality of magnetic compression for plasma density control ...

  20. Labs at-a-Glance: Princeton Plasma Physics Laboratory | U.S. DOE Office of

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

    Science (SC) Princeton Plasma Physics Laboratory Laboratories Laboratories Home Ames Laboratory Argonne National Laboratory Brookhaven National Laboratory Fermi National Accelerator Laboratory Lawrence Berkeley National Laboratory Oak Ridge National Laboratory Pacific Northwest National Laboratory Princeton Plasma Physics Laboratory SLAC National Accelerator Laboratory Thomas Jefferson National Accelerator Facility Laboratory Science Highlights Laboratory News Contact Information Office of

  1. Laboratory plasma physics experiments using merging supersonic plasma jets

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Hsu, S. C.; Moser, A. L.; Merritt, E. C.; Adams, C. S.; Dunn, J. P.; Brockington, S.; Case, A.; Gilmore, M.; Lynn, A. G.; Messer, S. J.; et al

    2015-04-01

    We describe a laboratory plasma physics experiment at Los Alamos National Laboratory that uses two merging supersonic plasma jets formed and launched by pulsed-power-driven railguns. The jets can be formed using any atomic species or mixture available in a compressed-gas bottle and have the following nominal initial parameters at the railgun nozzle exit: ne ≈ ni ~ 10¹⁶ cm⁻³, Te ≈ Ti ≈ 1.4 eV, Vjet ≈ 30–100 km/s, mean chargemore » $$\\bar{Z}$$ ≈ 1, sonic Mach number Ms ≡ Vjet/Cs > 10, jet diameter = 5 cm, and jet length ≈ 20 cm. Experiments to date have focused on the study of merging-jet dynamics and the shocks that form as a result of the interaction, in both collisional and collisionless regimes with respect to the inter-jet classical ion mean free path, and with and without an applied magnetic field. However, many other studies are also possible, as discussed in this paper.« less

  2. Laboratory plasma physics experiments using merging supersonic plasma jets

    SciTech Connect (OSTI)

    Hsu, S. C.; Moser, A. L.; Merritt, E. C.; Adams, C. S.; Dunn, J. P.; Brockington, S.; Case, A.; Gilmore, M.; Lynn, A. G.; Messer, S. J.; Witherspoon, F. D.

    2015-04-01

    We describe a laboratory plasma physics experiment at Los Alamos National Laboratory that uses two merging supersonic plasma jets formed and launched by pulsed-power-driven railguns. The jets can be formed using any atomic species or mixture available in a compressed-gas bottle and have the following nominal initial parameters at the railgun nozzle exit: ne ≈ ni ~ 10¹⁶ cm⁻³, Te ≈ Ti ≈ 1.4 eV, Vjet ≈ 30–100 km/s, mean charge $\\bar{Z}$ ≈ 1, sonic Mach number Ms ≡ Vjet/Cs > 10, jet diameter = 5 cm, and jet length ≈ 20 cm. Experiments to date have focused on the study of merging-jet dynamics and the shocks that form as a result of the interaction, in both collisional and collisionless regimes with respect to the inter-jet classical ion mean free path, and with and without an applied magnetic field. However, many other studies are also possible, as discussed in this paper.

  3. Laboratory plasma physics experiments using merging supersonic plasma jets

    SciTech Connect (OSTI)

    Hsu, S. C.; Moser, A. L.; Merritt, E. C.; Adams, C. S.; Dunn, J. P.; Brockington, S.; Case, A.; Gilmore, M.; Lynn, A. G.; Messer, S. J.; Witherspoon, F. D.

    2015-04-01

    We describe a laboratory plasma physics experiment at Los Alamos National Laboratory that uses two merging supersonic plasma jets formed and launched by pulsed-power-driven railguns. The jets can be formed using any atomic species or mixture available in a compressed-gas bottle and have the following nominal initial parameters at the railgun nozzle exit: ne ? ni ~ 10? cm?, Te ? Ti ? 1.4 eV, Vjet ? 30100 km/s, mean charge $\\bar{Z}$ ? 1, sonic Mach number Ms ? Vjet/Cs > 10, jet diameter = 5 cm, and jet length ? 20 cm. Experiments to date have focused on the study of merging-jet dynamics and the shocks that form as a result of the interaction, in both collisional and collisionless regimes with respect to the inter-jet classical ion mean free path, and with and without an applied magnetic field. However, many other studies are also possible, as discussed in this paper.

  4. Operational plasma density and laser parameters for future colliders based on laser-plasma accelerators

    SciTech Connect (OSTI)

    Schroeder, C. B.; Esarey, E.; Leemans, W. P.

    2012-12-21

    The operational plasma density and laser parameters for future colliders based on laser-plasma accelerators are discussed. Beamstrahlung limits the charge per bunch at low plasma densities. Reduced laser intensity is examined to improve accelerator efficiency in the beamstrahlung-limited regime.

  5. Honey, I Shrunk the Plasma: Studying Astrophysical Processes in Laboratory

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

    Experiments | Princeton Plasma Physics Lab February 14, 2015, 9:30am to 11:00am Science On Saturday MBG Auditorium Honey, I Shrunk the Plasma: Studying Astrophysical Processes in Laboratory Experiments Dr. Clayton Myers, Associate Research Physicist PPPL Abstract: PDF icon Myers.pdf Science on Saturday, 14FEB2015, "Honey, I Shrunk the Plasma: Studying Astrophysical Processess in Laboratory Experiments", Dr. Clayton Myers, PPPL Contact Information Website: Science on Saturday

  6. Princeton Plasma Physics Laboratory Honors Three Researchers | Princeton

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

    Plasma Physics Lab Princeton Plasma Physics Laboratory Honors Three Researchers March 12, 2012 Tweet Widget Google Plus One Share on Facebook Gallery: Kenneth Hill received the Kaul Prize for Excellence in Plasma Physics Research and Technology Development. (Photo by Elle Starkman, PPPL Office of Communications) Kenneth Hill received the Kaul Prize for Excellence in Plasma Physics Research and Technology Development. Robert Ellis received the PPPL Distinguished Engineering Fellow award.

  7. Directory - Center for Plasma in the Laboratory and Astrophysics - UW

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

    Madison Physics Department Directory UW Madison Center for Plasma in the Laboratory and Astrophysics Directory CPLA Home - Experiments Madison Symmetric Torus Madsion Dynamo Experiment Rotating Wall Machine Plasma-Couette Experiment Madison Plasma Dynamo Experiment - Theory Groups MHD Turbulence Transport in Fusion Devices Plasma Astrophysics RFP Theory - Multi-Institutional Centers Center for Magnetic Self Organization Center for Theory and Computation Center for Momentum Transport and Flow

  8. COLLOQUIUM: Frontiers in Plasma Science: A High Energy Density...

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

    January 13, 2016, 4:15pm to 5:30pm Colloquia MBG AUDITORIUM COLLOQUIUM: Frontiers in Plasma Science: A High Energy Density Perspective Dr. Bruce A. Remington Lawrence Livermore ...

  9. Laboratory Study Of Magnetic Reconnection With A Density Asymmetry Across The Current Sheet

    SciTech Connect (OSTI)

    Yoo, Joseph; Yamada, Massaaki; Ji, Hantao; Meyers,, Clayton E.; Jara-Almonte,; Chen, Li-Jen

    2014-04-18

    The effects of an upstream density asymmetry on magnetic reconnection are studied systematically in a laboratory plasma. Despite a significant upstream density asymmetry of up to 10, the reconnecting magnetic field pro file is not signifi cantly changed. On the other hand, the out-of-plane magnetic field profile is considerably modified; it is almost bipolar in structure with the density asymmetry, as compared to the quadrupolar structure in the symmetric configuration. The in-plane ion flow pattern and the electrostatic potential pro file are also affected by the density asymmetry. Strong bulk electron heating is observed near the low-density-side separatrix together with electromagnetic fluctuations in the lower hybrid frequency range. The dependence of the ion outflow and reconnection electric field on the density asymmetry is measured and compared with theoretical expectations.

  10. 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)

    2014-04-15

    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.

  11. Absorption spectroscopy of a laboratory photoionized plasma experiment at Z

    SciTech Connect (OSTI)

    Hall, I. M.; Durmaz, T.; Mancini, R. C.; Bailey, J. E.; Rochau, G. A.; Golovkin, I. E.; MacFarlane, J. J.

    2014-03-15

    The Z facility at the Sandia National Laboratories is the most energetic terrestrial source of X-rays and provides an opportunity to produce photoionized plasmas in a relatively well characterised radiation environment. We use detailed atomic-kinetic and spectral simulations to analyze the absorption spectra of a photoionized neon plasma driven by the x-ray flux from a z-pinch. The broadband x-ray flux both photoionizes and backlights the plasma. In particular, we focus on extracting the charge state distribution of the plasma and the characteristics of the radiation field driving the plasma in order to estimate the ionisation parameter.

  12. Normal and abnormal evolution of argon metastable density in high-density plasmas

    SciTech Connect (OSTI)

    Seo, B. H.; Kim, J. H.; You, S. J.

    2015-05-15

    A controversial problem on the evolution of Ar metastable density as a function of electron density (increasing trend versus decreasing trend) was resolved by discovering the anomalous evolution of the argon metastable density with increasing electron density (discharge power), including both trends of the metastable density [Daltrini et al., Appl. Phys. Lett. 92, 061504 (2008)]. Later, by virtue of an adequate physical explanation based on a simple global model, both evolutions of the metastable density were comprehensively understood as part of the abnormal evolution occurring at low- and high-density regimes, respectively, and thus the physics behind the metastable evolution has seemed to be clearly disclosed. In this study, however, a remarkable result for the metastable density behavior with increasing electron density was observed: even in the same electron density regime, there are both normal and abnormal evolutions of metastable-state density with electron density depending on the measurement position: The metastable density increases with increasing electron density at a position far from the inductively coupled plasma antenna but decreases at a position close to the antenna. The effect of electron temperature, which is spatially nonuniform in the plasma, on the electron population and depopulation processes of Argon metastable atoms with increasing electron density is a clue to understanding the results. The calculated results of the global model, including multistep ionization for the argon metastable state and measured electron temperature, are in a good agreement with the experimental results.

  13. Simulating Magnetized Laboratory Plasmas with Smoothed Particle Hydrodynamics

    SciTech Connect (OSTI)

    Johnson, J N

    2009-07-02

    The creation of plasmas in the laboratory continues to generate excitement in the physics community. Despite the best efforts of the intrepid plasma diagnostics community, the dynamics of these plasmas remains a difficult challenge to both the theorist and the experimentalist. This dissertation describes the simulation of strongly magnetized laboratory plasmas with Smoothed Particle Hydrodynamics (SPH), a method born of astrophysics but gaining broad support in the engineering community. We describe the mathematical formulation that best characterizes a strongly magnetized plasma under our circumstances of interest, and we review the SPH method and its application to astrophysical plasmas based on research by Phillips [1], Buerve [2], and Price and Monaghan [3]. Some modifications and extensions to this method are necessary to simulate terrestrial plasmas, such as a treatment of magnetic diffusion based on work by Brookshaw [4] and by Atluri [5]; we describe these changes as we turn our attention toward laboratory experiments. Test problems that verify the method are provided throughout the discussion. Finally, we apply our method to the compression of a magnetized plasma performed by the Compact Toroid Injection eXperiment (CTIX) [6] and show that the experimental results support our computed predictions.

  14. Top-5 Achievements at the Princeton Plasma Physics Laboratory in 2015 |

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

    Princeton Plasma Physics Lab Top-5 Achievements at the Princeton Plasma Physics Laboratory in 2015 By John Greenwald January 12, 2016 Tweet Widget Google Plus One Share on Facebook From top left: 1.Magnetic island geometry revealing the mechanism for the density limit. (Reprinted with permission from Phys. Plasmas 22, 022514 2015); 2.Carlos Paz-Soldan and Raffi Nazikian advanced understanding of the control of heat bursts; 3.interior of the NSTX-U showing the completed center stack; 4.W7-X

  15. High Density Sensor Network Development | The Ames Laboratory

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

    High Density Sensor Network Development

  16. OVERVIEW OF HIGH-DENSITY FRC RESEARCH ON FRX-L AT LOS ALAMOS NATIONAL LABORATORY.

    SciTech Connect (OSTI)

    Taccetti, J. M.; Zhang, S. Y.; Wurden, G. A.; Maqueda, R. J.; Tuszewski, M.; Siemon, R.; Begay, D.; Mignardot, E.; Sanchez, P.; Waganaar, B.; Degnan, J. H.; Sommars, W.; Grabowski, C.

    2002-10-07

    We present an overview of the FRC research on the Field Reversed configuration eXperiment – Liner (FRX-L) device at Los Alamos National Laboratory. This is a target plasma ‘injector’ to be used for magnetized target fusion (MTF) applications. MTF is an approach to fusion wherein a magnetized target plasma is compressed to fusion conditions. Our target plasma is an FRC because it has the required closed-field-line topology, and is translatable and compressible. The existing empirical database also indicates that the type of FRC required for MTF would be achievable. FRX-L includes the formation and translation of the FRC into a mock target chamber. We are currently in the process of forming the high-density FRC.

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

    SciTech Connect (OSTI)

    Palacio Mizrahi, J. H.

    2014-06-15

    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.

  18. On the density limit in the helicon plasma sources

    SciTech Connect (OSTI)

    Kotelnikov, Igor A.

    2014-12-15

    Existence of the density limit in the helicon plasma sources is revisited. The low- and high-frequency regimes of a helicon plasma source operation are distinguished. In the low-frequency regime with ω<√(ω{sub ci}ω{sub ce}), the density limit is deduced from the Golant-Stix criterion of the accessibility of the lower hybrid resonance. In the high-frequency case, ω>√(ω{sub ci}ω{sub ce}), an appropriate limit is given by the Shamrai-Taranov criterion. Both these criteria are closely related to the phenomenon of the coalescence of the helicon wave with the Trivelpiece-Gould mode. We draw a conclusion that the derived density limits are not currently achieved in existing devices, perhaps, because of high energy cost of gas ionization.

  19. New season of colloquia begins at Princeton Plasma Physics Laboratory |

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

    Princeton Plasma Physics Lab New season of colloquia begins at Princeton Plasma Physics Laboratory By Raphael Rosen September 15, 2015 Tweet Widget Google Plus One Share on Facebook The new colloquium committee. From left to right: Mike Mardenfeld, David Mikkelsen, Committee Administrator Carol Ann Austin, Brent Stratton (Photo by Elle Starkman) The new colloquium committee. From left to right: Mike Mardenfeld, David Mikkelsen, Committee Administrator Carol Ann Austin, Brent Stratton Just as

  20. Princeton Plasma Physics Laboratory achieves milestone, completing first

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

    part of heart of fusion experiment | Princeton Plasma Physics Lab Princeton Plasma Physics Laboratory achieves milestone, completing first part of heart of fusion experiment By John Greenwald March 22, 2013 Tweet Widget Google Plus One Share on Facebook The completed first section of the NSTX-U center stack. (Photo by Elle Starkman, PPPL Office of Communications) The completed first section of the NSTX-U center stack. Gallery: Related Images: Engineers and technicians at the U.S. Department

  1. Practicality of magnetic compression for plasma density control

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Gueroult, Renaud; Fisch, Nathaniel J.

    2016-03-16

    Here, plasma densification through magnetic compression has been suggested for time-resolved control of the wave properties in plasma-based accelerators [P. F. Schmit and N. J. Fisch, Phys. Rev. Lett. 109, 255003 (2012)]. Using particle in cell simulations with real mass ratio, the practicality of large magnetic compression on timescales shorter than the ion gyro-period is investigated. For compression times shorter than the transit time of a compressional Alfven wave across the plasma slab, results show the formation of two counter-propagating shock waves, leading to a highly non-uniform plasma density profile. Furthermore, the plasma slab displays large hydromagnetic like oscillations aftermore » the driving field has reached steady state. Peak compression is obtained when the two shocks collide in the mid-plane. At this instant, very large plasma heating is observed, and the plasmaβ is estimated to be about 1. Although these results point out a densification mechanism quite different and more complex than initially envisioned, these features still might be advantageous in particle accelerators.« less

  2. 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.

    1999-11-13

    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.

  3. Final Progress Report for Ionospheric Dusty Plasma In the Laboratory [Smokey Plasma

    SciTech Connect (OSTI)

    Robertson, Scott

    2010-09-28

    Ionospheric Dusty Plasma in the Laboratory is a research project with the purpose of finding and reproducing the characteristics of plasma in the polar mesosphere that is unusually cold (down to 140 K) and contains nanometer-sized dust particles. This final progress report summarizes results from four years of effort that include a final year with a no-cost extension.

  4. Beam Matching to a Plasma Wakefield Accelerator Using a Ramped Density

    Office of Scientific and Technical Information (OSTI)

    Profile at the Plasma Boundary (Conference) | SciTech Connect Conference: Beam Matching to a Plasma Wakefield Accelerator Using a Ramped Density Profile at the Plasma Boundary Citation Details In-Document Search Title: Beam Matching to a Plasma Wakefield Accelerator Using a Ramped Density Profile at the Plasma Boundary An important aspect of plasma wake field accelerators (PWFA) is stable propagation of the drive beam. In the under dense plasma regime, the drive beam creates an ion channel

  5. A novel electron density reconstruction method for asymmetrical toroidal plasmas

    SciTech Connect (OSTI)

    Shi, N.; Ohshima, S.; Minami, T.; Nagasaki, K.; Yamamoto, S.; Mizuuchi, T.; Okada, H.; Kado, S.; Kobayashi, S.; Konoshima, S.; Sano, F.; Tanaka, K.; Ohtani, Y.; Zang, L.; Kenmochi, N.

    2014-05-15

    A novel reconstruction method is developed for acquiring the electron density profile from multi-channel interferometric measurements of strongly asymmetrical toroidal plasmas. It is based on a regularization technique, and a generalized cross-validation function is used to optimize the regularization parameter with the aid of singular value decomposition. The feasibility of method could be testified by simulated measurements based on a magnetic configuration of the flexible helical-axis heliotron device, Heliotron J, which has an asymmetrical poloidal cross section. And the successful reconstruction makes possible to construct a multi-channel Far-infrared laser interferometry on this device. The advantages of this method are demonstrated by comparison with a conventional method. The factors which may affect the accuracy of the results are investigated, and an error analysis is carried out. Based on the obtained results, the proposed method is highly promising for accurately reconstructing the electron density in the asymmetrical toroidal plasma.

  6. Stable laser–plasma accelerators at low densities

    SciTech Connect (OSTI)

    Li, Song; Hafz, Nasr A. M. Mirzaie, Mohammad; Ge, Xulei; Sokollik, Thomas; Chen, Min; Sheng, Zhengming; Zhang, Jie

    2014-07-28

    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 μm) 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.

  7. A scheme to produce high density and high temperature plasma for opacity measurement

    SciTech Connect (OSTI)

    Xu, Yan; Wu, SiZhong; Zheng, WuDi

    2015-04-15

    The opacity of shock-compressed material is of general scientific interest for astrophysical plasmas and for inertial confinement fusion research. A proposal is suggested to produce high temperature plasma with density around 1 g/cm{sup −3}. Two types of opacity target (the sandwich target and the foam enhanced sandwich target) are investigated numerically. The foam enhanced sandwich target has structure of foam–solid-sample-solid-foam. The foam will increase laser absorption efficiency and the ablating pressure. Hydrodynamic simulations confirm that the laser can be fully absorbed by the under-critical-density foam and a faster shock is produced inside the CH layer. High intensity lasers heat opacity target from both sides. The CH layers must be thick enough to keep the laser away from the sample. The laser-driven shocks move inward and collide at the center. Part of their kinetic energy is converted into internal energy and high density and high temperature local thermodynamic equilibrium sample plasma is produced. The plasma produced by laser heating the foam enhanced sandwich target has higher sample temperature than by laser heating the sandwich target. It may be useful for measuring the opacity of shock compressed material in laboratory.

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

    SciTech Connect (OSTI)

    Perego, M.; Gunzburger, M. D.; Howell, P. D.; Ockendon, J. R.; Allen, J. E.

    2013-05-15

    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.

  9. Effects of argon gas pressure on its metastable-state density in high-density plasmas

    SciTech Connect (OSTI)

    Seo, B. H.; Kim, J. H.; You, S. J.

    2015-05-15

    The effect of argon gas pressure on its metastable density in inductively coupled plasmas (ICPs) is investigated by using the laser-induced fluorescence method. Our results show that the metastable-state density of argon varies with the gas pressure depending on the measurement position; the density decreases with the pressure at a position far from the ICP antenna, whereas it increases with the pressure at a position near the antenna. This contrast in the metastable-state density trend with the pressure is explained by considering the electron temperature variations at the two measurement positions. The theoretical interpretation and calculation using a global model are also addressed in detail in this paper.

  10. P24 Plasma Physics Summer School 2012 Los Alamos National Laboratory Summer lecture series for students

    SciTech Connect (OSTI)

    Intrator, Thomas P.; Bauer, Bruno; Fernandez, Juan C.; Daughton, William S.; Flippo, Kirk A.; Weber, Thomas; Awe, Thomas J.; Kim, Yong Ho

    2012-09-07

    This report covers the 2012 LANL summer lecture series for students. The lectures were: (1) Tom Intrator, P24 LANL: Kick off, Introduction - What is a plasma; (2) Bruno Bauer, Univ. Nevada-Reno: Derivation of plasma fluid equations; (3) Juan Fernandez, P24 LANL Overview of research being done in p-24; (4) Tom Intrator, P24 LANL: Intro to dynamo, reconnection, shocks; (5) Bill Daughton X-CP6 LANL: Intro to computational particle in cell methods; (6) Kirk Flippo, P24 LANL: High energy density plasmas; (7) Thom Weber, P24 LANL: Energy crisis, fission, fusion, non carbon fuel cycles; (8) Tom Awe, Sandia National Laboratory: Magneto Inertial Fusion; and (9) Yongho Kim, P24 LANL: Industrial technologies.

  11. 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

    2009-02-12

    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.

  12. Princeton Plasma Physics Laboratory FY2003 Annual Highlights

    SciTech Connect (OSTI)

    Editors: Carol A. Phillips; Anthony R. DeMeo

    2004-08-23

    The Princeton Plasma Physics Laboratory FY2003 Annual Highlights report provides a summary of the activities at the Laboratory for the fiscal year--1 October 2002 through 30 September 2003. The report includes the Laboratory's Mission and Vision Statements, a message ''From the Director,'' summaries of the research and engineering activities by project, and sections on Technology Transfer, the Graduate and Science Education Programs, Awards and Honors garnered by the Laboratory and the employees, and the Year in Pictures. There is also a listing of the Laboratory's publications for the year and a section of the abbreviations, acronyms, and symbols used throughout the report. In the PDF document, links have been created from the Table of Contents to each section. You can also return to the Table of Contents from the beginning page of each section. The PPPL Highlights for fiscal year 2003 is also available in hardcopy format. To obtain a copy e-mail Publications and Reports at: pub-reports@pppl.gov. Be sure to include your complete mailing address

  13. Laboratory Evidence for Stochastic Plasma-Wave Growth

    SciTech Connect (OSTI)

    Austin, D. R.; Hole, M. J.; Robinson, P. A.; Cairns, Iver H.; Dallaqua, R.

    2007-11-16

    The first laboratory confirmation of stochastic growth theory is reported. Floating potential fluctuations are measured in a vacuum arc centrifuge using a Langmuir probe. Statistical analysis of the energy density reveals a lognormal distribution over roughly 2 orders of magnitude, with a high-field nonlinear cutoff whose spatial dependence is consistent with the predicted eigenmode profile. These results are consistent with stochastic growth and nonlinear saturation of a spatially extended eigenmode, the first evidence for stochastic growth of an extended structure.

  14. OSTIblog Articles in the Princeton Plasma Physics Laboratory Topic | OSTI,

    Office of Scientific and Technical Information (OSTI)

    US Dept of Energy Office of Scientific and Technical Information Princeton Plasma Physics Laboratory Topic Snowflake Science by Kate Bannan 13 Dec, 2011 in Science Communications 4351 snowflake.jpg Snowflake Science Read more about 4351 With winter just around the corner, can snow be far behind? We've all heard that no two snowflakes are alike, but what do we really know about them? Snowflakes always have six sides. Their form and shape depends on temperature and moisture. Snowflake shapes

  15. Two density peaks in low magnetic field helicon plasma

    SciTech Connect (OSTI)

    Wang, Y.; Zhao, G.; Ouyang, J. T. E-mail: lppmchenqiang@hotmail.com; Liu, Z. W.; Chen, Q. E-mail: lppmchenqiang@hotmail.com

    2015-09-15

    In this paper, we report two density peaks in argon helicon plasma under an axial magnetic field from 0 G to 250 G with Boswell-type antenna driven by radio frequency (RF) power of 13.56 MHz. The first peak locates at 40–55 G and the second one at 110–165 G, as the RF power is sustainably increased from 100 W to 250 W at Ar pressure of 0.35 Pa. The absorbed power of two peaks shows a linear relationship with the magnetic field. End views of the discharge taken by intensified charge coupled device reveal that, when the first peak appeared, the discharge luminance moves to the edge of the tube as the magnetic field increases. For the second peak, the strong discharge area is centered at the two antenna legs after the magnetic field reaches a threshold value. Comparing with the simulation, we suggest that the efficient power absorption of two peaks at which the efficient power absorption mainly appears in the near-antenna region is due to the mode conversion in bounded non-uniform helicon plasma. The two low-field peaks are caused, to some extent, by the excitation of Trivelpiece-Gould wave through non-resonance conversion.

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

    SciTech Connect (OSTI)

    Nishikawa, Takeshi

    2014-07-15

    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.

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

    SciTech Connect (OSTI)

    Greenly, John B.; Seyler, Charles

    2014-03-30

    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

  18. RFP Workshops - Center for Plasma in the Laboratory and Astrophysics...

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

    Rotating Wall Machine Plasma-Couette Experiment Madison Plasma Dynamo Experiment - Theory Groups MHD Turbulence Transport in Fusion Devices Plasma Astrophysics RFP Theory -...

  19. Talks - Publications - Center for Plasma in the Laboratory and...

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

    Rotating Wall Machine Plasma-Couette Experiment Madison Plasma Dynamo Experiment - Theory Groups MHD Turbulence Transport in Fusion Devices Plasma Astrophysics RFP Theory -...

  20. Plasma source ion implantation research and applications at Los Alamos National Laboratory

    SciTech Connect (OSTI)

    Munson, C.P.; Faehl, R.J.; Henins, I.

    1996-12-31

    Plasma Source Ion Implantation research at Los Alamos Laboratory includes direct investigation of the plasma and materials science involved in target surface modification, numerical simulations of the implantation process, and supporting hardware engineering. Target materials of Al, Cr, Cu-Zn, Mg, Ni, Si, Ti, W, and various Fe alloys have been processed using plasmas produced from Ar, NH{sub 3}, N{sub 2}, CH{sub 4}, and C{sub 2}H{sub 2} gases. Individual targets with surface areas as large as {approximately}4 m{sup 2}, or weighing up to 1200 kg, have been treated in the large LANL facility. In collaboration with General Motors and the University of Wisconsin, a process has been developed for application of hard, low friction, diamond-like-carbon layers on assemblies of automotive pistons. Numerical simulations have been performed using a 2{1/2}-D particle- in-cell code, which yields time-dependent implantation energy, dose, and angle of arrival for ions at the target surface for realistic geometries. Plasma source development activities include the investigation of pulsed, inductively coupled sources capable of generating highly dissociated N{sup +} with ion densities n{sub i} {approximately} 10{sup 11}/cm{sup 3}, at {approximately}100 W average input power. Cathodic arc sources have also been used to produce filtered metallic and C plasmas for implantation and deposition either in vacuum, or in conjunction with a background gas for production of highly adherent ceramic coatings.

  1. Basic Research Needs for High Energy Density Laboratory Physics

    National Nuclear Security Administration (NNSA)

    On the cover: Invisible infrared light from the 200-trillion watt Trident Laser enters from the bottom to interact with a one-micrometer thick foil target in the center of the photo. The laser pulse produces a plasma - an ionized gas - many times hotter than the center of the sun, which lasts for a trillionth of a second. During this time some electrons from the foil are accelerated to virtually the speed of light, and some ions are accelerated to energies of tens of millions of volts. In this

  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. King, Lyon B.

    2014-05-15

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

    Office of Science (SC) Website

    Princeton Plasma Physics Laboratory Laboratory Policy (LP) LP Home About Laboratory Appraisal Process FY 2015 Report Cards FY 2014 Report Cards FY 2013 Report Cards Report Card Archives Laboratory Planning Process Laboratory Directed Research and Development (LDRD) Management & Operating (M&O) Contracts Technology Transfer Strategic Partnership Projects (SPP) Contact Information Laboratory Policy U.S. Department of Energy SC-32/Forrestal Building 1000 Independence Ave., SW Washington,

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

    Office of Science (SC) Website

    Princeton Plasma Physics Laboratory Laboratory Policy (LP) LP Home About Laboratory Appraisal Process FY 2015 Report Cards FY 2014 Report Cards FY 2013 Report Cards Report Card Archives Laboratory Planning Process Laboratory Directed Research and Development (LDRD) Management & Operating (M&O) Contracts Technology Transfer Strategic Partnership Projects (SPP) Contact Information Laboratory Policy U.S. Department of Energy SC-32/Forrestal Building 1000 Independence Ave., SW Washington, DC

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

    Office of Science (SC) Website

    Princeton Plasma Physics Laboratory Laboratory Policy (LP) LP Home About Laboratory Appraisal Process FY 2015 Report Cards FY 2014 Report Cards FY 2013 Report Cards Report Card Archives Laboratory Planning Process Laboratory Directed Research and Development (LDRD) Management & Operating (M&O) Contracts Technology Transfer Strategic Partnership Projects (SPP) Contact Information Laboratory Policy U.S. Department of Energy SC-32/Forrestal Building 1000 Independence Ave., SW Washington, DC

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

    Office of Science (SC) Website

    Princeton Plasma Physics Laboratory Laboratory Policy (LP) LP Home About Laboratory Appraisal Process FY 2015 Report Cards FY 2014 Report Cards FY 2013 Report Cards Report Card Archives Laboratory Planning Process Laboratory Directed Research and Development (LDRD) Management & Operating (M&O) Contracts Technology Transfer Strategic Partnership Projects (SPP) Contact Information Laboratory Policy U.S. Department of Energy SC-32/Forrestal Building 1000 Independence Ave., SW Washington, DC

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

    Office of Science (SC) Website

    Princeton Plasma Physics Laboratory Laboratory Policy (LP) LP Home About Laboratory Appraisal Process FY 2015 Report Cards FY 2014 Report Cards FY 2013 Report Cards Report Card Archives Laboratory Planning Process Laboratory Directed Research and Development (LDRD) Management & Operating (M&O) Contracts Technology Transfer Strategic Partnership Projects (SPP) Contact Information Laboratory Policy U.S. Department of Energy SC-32/Forrestal Building 1000 Independence Ave., SW Washington, DC

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

    Office of Science (SC) Website

    Princeton Plasma Physics Laboratory Laboratory Policy (LP) LP Home About Laboratory Appraisal Process FY 2015 Report Cards FY 2014 Report Cards FY 2013 Report Cards Report Card Archives Laboratory Planning Process Laboratory Directed Research and Development (LDRD) Management & Operating (M&O) Contracts Technology Transfer Strategic Partnership Projects (SPP) Contact Information Laboratory Policy U.S. Department of Energy SC-32/Forrestal Building 1000 Independence Ave., SW Washington, DC

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

    Office of Science (SC) Website

    Princeton Plasma Physics Laboratory Laboratory Policy (LP) LP Home About Laboratory Appraisal Process FY 2015 Report Cards FY 2014 Report Cards FY 2013 Report Cards Report Card Archives Laboratory Planning Process Laboratory Directed Research and Development (LDRD) Management & Operating (M&O) Contracts Technology Transfer Strategic Partnership Projects (SPP) Contact Information Laboratory Policy U.S. Department of Energy SC-32/Forrestal Building 1000 Independence Ave., SW Washington, DC

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

    Office of Science (SC) Website

    Princeton Plasma Physics Laboratory Laboratory Policy (LP) LP Home About Laboratory Appraisal Process FY 2015 Report Cards FY 2014 Report Cards FY 2013 Report Cards Report Card Archives Laboratory Planning Process Laboratory Directed Research and Development (LDRD) Management & Operating (M&O) Contracts Technology Transfer Strategic Partnership Projects (SPP) Contact Information Laboratory Policy U.S. Department of Energy SC-32/Forrestal Building 1000 Independence Ave., SW Washington, DC

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

    Office of Science (SC) Website

    Princeton Plasma Physics Laboratory Laboratory Policy (LP) LP Home About Laboratory Appraisal Process FY 2015 Report Cards FY 2014 Report Cards FY 2013 Report Cards Report Card Archives Laboratory Planning Process Laboratory Directed Research and Development (LDRD) Management & Operating (M&O) Contracts Technology Transfer Strategic Partnership Projects (SPP) Contact Information Laboratory Policy U.S. Department of Energy SC-32/Forrestal Building 1000 Independence Ave., SW Washington, DC

  12. Cancer therapy using non-thermal atmospheric pressure plasma with ultra-high electron density

    SciTech Connect (OSTI)

    Tanaka, Hiromasa; Mizuno, Masaaki; Toyokuni, Shinya; Maruyama, Shoichi; Kodera, Yasuhiro; Terasaki, Hiroko; Adachi, Tetsuo; Kato, Masashi; Kikkawa, Fumitaka; Hori, Masaru

    2015-12-15

    Cancer therapy using non-thermal atmospheric pressure plasma is a big challenge in plasma medicine. Reactive species generated from plasma are key factors for treating cancer cells, and thus, non-thermal atmospheric pressure plasma with high electron density has been developed and applied for cancer treatment. Various cancer cell lines have been treated with plasma, and non-thermal atmospheric plasma clearly has anti-tumor effects. Recent innovative studies suggest that plasma can both directly and indirectly affect cells and tissues, and this observation has widened the range of applications. Thus, cancer therapy using non-thermal atmospheric pressure plasma is promising. Animal experiments and understanding the mode of action are essential for clinical application in the future. A new academic field that combines plasma science, the biology of free radicals, and systems biology will be established.

  13. PPPL Launches Expanded New Laboratory for Research on the use of Plasma to

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Synthesize Nanoparticles | Department of Energy PPPL Launches Expanded New Laboratory for Research on the use of Plasma to Synthesize Nanoparticles PPPL Launches Expanded New Laboratory for Research on the use of Plasma to Synthesize Nanoparticles July 13, 2016 - 2:38pm Addthis Inside the new nanolaboratory. Front and center from left: Philip Efthimion, head of the Plasma Science and Technology Department, Charles Gentile, lead engineer for the nanolab, and Yevgeny Raitses, principal

  14. High-efficiency acceleration in the laser wakefield by a linearly increasing plasma density

    SciTech Connect (OSTI)

    Dong, Kegong; Wu, Yuchi; Zhu, Bin; Zhang, Zhimeng; Zhao, Zongqing; Zhou, Weimin; Hong, Wei; Cao, Leifeng; Gu, Yuqiu

    2014-12-15

    The acceleration length and the peak energy of the electron beam are limited by the dephasing effect in the laser wakefield acceleration with uniform plasma density. Based on 2D-3V particle in cell simulations, the effects of a linearly increasing plasma density on the electron acceleration are investigated broadly. Comparing with the uniform plasma density, because of the prolongation of the acceleration length and the gradually increasing accelerating field due to the increasing plasma density, the electron beam energy is twice higher in moderate nonlinear wakefield regime. Because of the lower plasma density, the linearly increasing plasma density can also avoid the dark current caused by additional injection. At the optimal acceleration length, the electron energy can be increased from 350 MeV (uniform) to 760 MeV (linearly increasing) with the energy spread of 1.8%, the beam duration is 5 fs and the beam waist is 1.25 μm. This linearly increasing plasma density distribution can be achieved by a capillary with special gas-filled structure, and is much more suitable for experiment.

  15. Talbot-Lau X-ray Deflectometer electron density diagnostic for laser and pulsed power high energy density plasma experiments

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Valdivia, M. P.; Stutman, D.; Stoeckl, C.; Mileham, C.; Begishev, I.; Theobald, W.; Bromage, J.; Regan, S. P.; Klein, S. R.; Munoz-Cordoves, G.; et al

    2016-04-21

    Talbot-Lau X-ray Deflectometry has been developed as an electron density diagnostic for High Energy Density plasmas. The technique can deliver x-ray refraction, attenuation, elemental composition, and scatter information from a single Moiré image. An 8 keV Talbot-Lau interferometer was deployed using laser and x-pinch backlighters. Grating survival and electron density mapping was demonstrated for 25-29 J, 8-30 ps laser pulses using copper foil targets. Moire pattern formation and grating survival was also observed using a copper x-pinch driven at 400 kA, ~1 kA/ns. Lastly, these results demonstrate the potential of TXD as an electron density diagnostic for HED plasmas.

  16. History - Center for Plasma in the Laboratory and Astrophysics - UW Madison

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

    Physics Department History UW Madison Center for Plasma in the Laboratory and Astrophysics History CPLA Home - Experiments Madison Symmetric Torus Madsion Dynamo Experiment Rotating Wall Machine Plasma-Couette Experiment Madison Plasma Dynamo Experiment - Theory Groups MHD Turbulence Transport in Fusion Devices Plasma Astrophysics RFP Theory - Multi-Institutional Centers Center for Magnetic Self Organization Center for Theory and Computation Center for Momentum Transport and Flow

  17. CPLA non conference publications Center for Plasma in the Laboratory and

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

    Astrophysics - UW Madison Physics Department Seminars > Seminar Slides UW Madison Center for Plasma in the Laboratory and Astrophysics Publications : non conference CPLA Home - Experiments Madison Symmetric Torus Madsion Dynamo Experiment Rotating Wall Machine Plasma-Couette Experiment Madison Plasma Dynamo Experiment - Theory Groups MHD Turbulence Transport in Fusion Devices Plasma Astrophysics RFP Theory - Multi-Institutional Centers Center for Magnetic Self Organization Center for

  18. Staff Info - People - Center for Plasma in the Laboratory and Astrophysics

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

    - UW Madison Physics Department Staff Info UW Madison Center for Plasma in the Laboratory and Astrophysics Staff Info CPLA Home - Experiments Madison Symmetric Torus Madsion Dynamo Experiment Rotating Wall Machine Plasma-Couette Experiment Madison Plasma Dynamo Experiment - Theory Groups MHD Turbulence Transport in Fusion Devices Plasma Astrophysics RFP Theory - Multi-Institutional Centers Center for Magnetic Self Organization Center for Theory and Computation Center for Momentum Transport

  19. Lab Phone Numbers - Center for Plasma in the Laboratory and Astrophysics -

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

    UW Madison Physics Department Lab Phone Numbers UW Madison Center for Plasma in the Laboratory and Astrophysics Lab Phone Numbers CPLA Home - Experiments Madison Symmetric Torus Madsion Dynamo Experiment Rotating Wall Machine Plasma-Couette Experiment Madison Plasma Dynamo Experiment - Theory Groups MHD Turbulence Transport in Fusion Devices Plasma Astrophysics RFP Theory - Multi-Institutional Centers Center for Magnetic Self Organization Center for Theory and Computation Center for Momentum

  20. Center for Plasma in the Laboratory and Astrophysics - UW Madison Physics

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

    Department Group UW Madison Center for Plasma in the Laboratory and Astrophysics CPLA Home - Experiments Madison Symmetric Torus Madsion Dynamo Experiment Rotating Wall Machine Plasma-Couette Experiment Madison Plasma Dynamo Experiment - Theory Groups MHD Turbulence Transport in Fusion Devices Plasma Astrophysics RFP Theory - Multi-Institutional Centers Center for Magnetic Self Organization Center for Theory and Computation Center for Momentum Transport and Flow Organization About CPLA

  1. Links - Center for Plasma in the Laboratory and Astrophysics - UW Madison

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

    Physics Department Links UW Madison Center for Plasma in the Laboratory and Astrophysics Links CPLA Home - Experiments Madison Symmetric Torus Madsion Dynamo Experiment Rotating Wall Machine Plasma-Couette Experiment Madison Plasma Dynamo Experiment - Theory Groups MHD Turbulence Transport in Fusion Devices Plasma Astrophysics RFP Theory - Multi-Institutional Centers Center for Magnetic Self Organization Center for Theory and Computation Center for Momentum Transport and Flow Organization

  2. Radiation-Matter Coupling for Low Density Plasmas (Conference...

    Office of Scientific and Technical Information (OSTI)

    Citation Details In-Document Search Title: Radiation-Matter Coupling for Low Density ... considered when constructing transport algorithms that are intended to provide ...

  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)

    Mega-Macas, A.; Vizcano-de-Julin, A.; Cortzar, O. D.

    2014-03-15

    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. The density and velocity of plasma bullets propagating along one dielectric tube

    SciTech Connect (OSTI)

    Ji, Longfei; Xia, Yang; Bi, Zhenhua; Niu, Jinhai; Liu, Dongping

    2015-08-15

    This study shows that the propagation of plasma bullets along one dielectric tube is strongly affected by many discharge parameters, such as the waveform of applied voltage (AC or pulsed DC), peak voltage, He flow rate, and the frequency of AC voltage. Analysis indicates that the density and velocity of plasma bullets are mainly determined by the electric field at the front of plasma bullets. These discharge parameters may significantly influence the distribution of plasma potential along the tube, thus control the electric field at the front of plasma bullets and their propagation. An increase in the pulsed DC voltage with its rise time of <40-50 ns can lead to an obvious improvement in the electric field at the front of plasma bullets, resulting in generation of a plasma in the high density gas and a fast propagation of plasma bullets. He flowing through the tube can contribute to the surface diffusion of charged species, and greatly increase the electric field at the front of plasma bullets. During the propagation of plasma bullets, their density is decreased due to the surface recombination of charged species, such as electrons and ions.

  5. Measurements of continuum lowering in solid-density plasmas created from elements and compounds

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Ciricosta, O.; Vinko, S. M.; Barbrel, B.; Rackstraw, D. S.; Preston, T. R.; Burian, T.; Chalupský, J.; Cho, B. I.; Chung, H. -K.; Dakovski, G. L.; et al

    2016-05-23

    The effect of a dense plasma environment on the energy levels of an embedded ion is usually described in terms of the lowering of its continuum level. For strongly coupled plasmas, the phenomenon is intimately related to the equation of state; hence, an accurate treatment is crucial for most astrophysical and inertial-fusion applications, where the case of plasma mixtures is of particular interest. In this study, we present an experiment showing that the standard density-dependent analytical models are inadequate to describe solid-density plasmas at the temperatures studied, where the reduction of the binding energies for a given species is unaffectedmore » by the different plasma environment (ion density) in either the element or compounds of that species, and can be accurately estimated by calculations only involving the energy levels of an isolated neutral atom. Lastly, the results have implications for the standard approaches to the equation of state calculations.« less

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

    SciTech Connect (OSTI)

    Habibi, M.; Ghamari, F.

    2012-10-15

    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.

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

    DOE Patents [OSTI]

    Thode, L.E.

    A device and method for relativistic electron beam heating of a high density plasma in a small localized region are described. 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/.

  8. Experimental observation of 3-D, impulsive reconnection events in a laboratory plasma

    SciTech Connect (OSTI)

    Dorfman, S.; Ji, H.; Yamada, M.; Yoo, J.; Lawrence, E.; Myers, C.; Tharp, T. D.

    2014-01-15

    Fast, impulsive reconnection is commonly observed in laboratory, space, and astrophysical plasmas. In this work, impulsive, local, 3-D reconnection is identified for the first time in a laboratory current sheet. The two-fluid, impulsive reconnection events observed on the Magnetic Reconnection Experiment (MRX) [Yamada et al., Phys Plasmas 4, 1936 (1997)] cannot be explained by 2-D models and are therefore fundamentally three-dimensional. Several signatures of flux ropes are identified with these events; 3-D high current density regions with O-point structure form during a slow buildup period that precedes a fast disruption of the reconnecting current layer. The observed drop in the reconnection current and spike in the reconnection rate during the disruption are due to ejection of these flux ropes from the layer. Underscoring the 3-D nature of the events, strong out-of-plane gradients in both the density and reconnecting magnetic field are found to play a key role in this process. Electromagnetic fluctuations in the lower hybrid frequency range are observed to peak at the disruption time; however, they are not the key physics responsible for the impulsive phenomena observed. Important features of the disruption dynamics cannot be explained by an anomalous resistivity model. An important discrepancy in the layer width and force balance between the collisionless regime of MRX and kinetic simulations is also revisited. The wider layers observed in MRX may be due to the formation of flux ropes with a wide range of sizes; consistent with this hypothesis, flux rope signatures are observed down to the smallest scales resolved by the diagnostics. Finally, a 3-D two-fluid model is proposed to explain how the observed out-of-plane variation may lead to a localized region of enhanced reconnection that spreads in the direction of the out-of-plane electron flow, ejecting flux ropes from the layer in a 3-D manner.

  9. Energy density dependence of hydrogen combustion efficiency in atmospheric pressure microwave plasma

    SciTech Connect (OSTI)

    Yoshida, T.; Ezumi, N.; Sawada, K.; Tanaka, Y.; Tanaka, M.; Nishimura, K.

    2015-03-15

    The recovery of tritium in nuclear fusion plants is a key issue for safety. So far, the oxidation procedure using an atmospheric pressure plasma is expected to be part of the recovery method. In this study, in order to clarify the mechanism of hydrogen oxidation by plasma chemistry, we have investigated the dependence of hydrogen combustion efficiency on gas flow rate and input power in the atmospheric pressure microwave plasma. It has been found that the combustion efficiency depends on energy density of absorbed microwave power. Hence, the energy density is considered as a key parameter for combustion processes. Also neutral gas temperatures inside and outside the plasma were measured by an optical emission spectroscopy method and thermocouple. The result shows that the neutral gas temperature in the plasma is much higher than the outside temperature of plasma. The high neutral gas temperature may affect the combustion reaction. (authors)

  10. Publications - Center for Plasma in the Laboratory and Astrophysics - UW

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

    Madison Physics Department Publications CPLA Home - Experiments Madison Symmetric Torus Madsion Dynamo Experiment Rotating Wall Machine Plasma-Couette Experiment Madison Plasma Dynamo Experiment - Theory Groups MHD Turbulence Transport in Fusion Devices Plasma Astrophysics RFP Theory - Multi-Institutional Centers Center for Magnetic Self Organization Center for Theory and Computation Center for Momentum Transport and Flow Organization About CPLA Directory Publications Links CPLA Schedule

  11. Conferences - Publications - Center for Plasma in the Laboratory and

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

    Astrophysics - UW Madison Physics Department Publications: Conferences CPLA Home - Experiments Madison Symmetric Torus Madsion Dynamo Experiment Rotating Wall Machine Plasma-Couette Experiment Madison Plasma Dynamo Experiment - Theory Groups MHD Turbulence Transport in Fusion Devices Plasma Astrophysics RFP Theory - Multi-Institutional Centers Center for Magnetic Self Organization Center for Theory and Computation Center for Momentum Transport and Flow Organization About CPLA Directory

  12. Trapping of dust and dust acoustic waves in laboratory plasmas

    SciTech Connect (OSTI)

    Prabhakara, H.R.; Tanna, V.L. [Institute for Plasma Research, Bhat, Gandhinagar 382 424 (India)] [Institute for Plasma Research, Bhat, Gandhinagar 382 424 (India)

    1996-08-01

    Trapping of negatively charged dust particles is observed in a hot cathode plasma discharge when a layer of dust is exposed to the plasma. The particles are visible in the scattered He{endash}Ne laser light. The trajectories of individual particles have been photographed. The dust particles are excluded from the sheath region of any object in the plasma. The intensity of scattered light as well as the potential on a floating Langmuir probe show coherent fluctuations in the frequency range 1{endash}15 Hz. After several hours of exposure to the plasma, the dust layer develops striations similar to those on sand dunes. Trapping of dust particles by the plasma and the possible identification of the observed low-frequency fluctuations with dust acoustic waves are discussed. {copyright} {ital 1996 American Institute of Physics.}

  13. 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

    2013-09-21

    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.

  14. Effect of secondary emission on the argon plasma afterglow with large dust density

    SciTech Connect (OSTI)

    Denysenko, I. B.; Azarenkov, N. A.; Burmaka, G. P.; Stefanovi?, I.

    2015-02-15

    A zero-dimensional, space-averaged model for argon plasma afterglow with large dust density is developed. In the model, three groups of electrons in the plasma afterglow are assumed: (i) thermal electrons with Maxwellian distribution, (ii) energetic electrons generated by metastable-metastable collisions (metastable pooling), and (iii) secondary electrons generated at collisions of ions with the electrodes, which have sufficiently large negative voltages in the afterglow. The model calculates the time-dependencies for electron densities in plasma afterglow based on experimental decay times for metastable density and electrode bias. The effect of secondary emission on electron density in the afterglow is estimated by varying secondary emission yields. It is found that this effect is less important than metastable pooling. The case of dust-free plasma afterglow is considered also, and it is found that in the afterglow the effect of secondary emission may be more important than metastable pooling. The secondary emission may increase thermal electron density n{sub e} in dust-free and dusty plasma afterglows on a few ten percentages. The calculated time dependencies for n{sub e} in dust-free and dusty plasma afterglows describe well the experimental results.

  15. Hierarchy of beam plasma instabilities up to high beam densities for fast ignition scenario

    SciTech Connect (OSTI)

    Bret, A.; Deutsch, C.

    2005-08-15

    The hierarchy of electromagnetic instabilities suffered by a relativistic electron beam passing through a plasma is investigated. The fluid approximation is used and beam densities up to the plasma one are considered. The hierarchy between instabilities is established in terms of two parameters only: the beam relativistic factor and the ratio n{sub b}/n{sub p} of the beam density to the plasma one. It is found that for n{sub b}/n{sub p} < or approx. 0.53, the most unstable modes are a mix between filamentation and two-stream instabilities. Beyond this limit, filamentation instability may dominate, depending on the beam relativistic factor. The largest growth rates are found for a beam density slightly smaller than the plasma one.

  16. Beam plasma electromagnetic instabilities in a smooth density gradient: Application to the fast ignition scenario

    SciTech Connect (OSTI)

    Bret, A.; Deutsch, C.

    2005-10-01

    The integrated growth rate of various relativistic beam/plasma instabilities in a weakly varying plasma density gradient is calculated using a WKB-like approximation. It is proven that such an assumption can be made in fast ignition scenario conditions. The formalism is applied to the two-stream, the filamentation, and the two-stream/filamentation instabilities, the latter instability being a mixture of the former two, and is the fastest growing one. The results are restricted to collisionless plasmas and nonrelativistic beam and plasma temperatures. Filamentation instability is reduced by the density gradient and eventually does not develop in the core, whereas two-stream and two-stream/filamentation instabilities should saturate even before they feel the gradient. Various effects connected to the density gradient are discussed. It is found they should be negligible as long as these later instabilities remain in their respective linear regime.

  17. Density and potential measurements in an intense ion-beam-generated plasma

    SciTech Connect (OSTI)

    Abt, N.E.

    1982-05-01

    Neutral beams are created by intense large area ion beams which are neutralized in a gas cell. The interaction of the beam with the gas cell creates a plasma. Such a plasma is studied here. The basic plasma parameters, electron temperature, density, and plasma potential, are measured as a function of beam current and neutral gas pressure. These measurements are compared to a model based on the solution of Poisson's equation. Because of the cylindrical geometry the equation cannot be solved analytically. Details of the numerical method are presented.

  18. Observation of Ion Acceleration and Heating during Collisionless Magnetic Reconnection in a Laboratory Plasma

    Office of Scientific and Technical Information (OSTI)

    35 PPPL- 4835 Observation of Ion Acceleration and Heating during Collisionless Magnetic Reconnection in a Laboratory Plasma December, 2012 Jongsoo Yoo, Masaaki Yamada, HantaoJi and Clayton E. Myers Princeton Plasma Physics Laboratory Report Disclaimers Full Legal Disclaimer This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, nor any of their contractors,

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

    DOE Patents [OSTI]

    Thode, Lester E.

    1981-01-01

    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.

  20. Parallel resistivity and ohmic heating of laboratory dipole plasmas

    SciTech Connect (OSTI)

    Fox, W.

    2012-08-15

    The parallel resistivity is calculated in the long-mean-free-path regime for the dipole plasma geometry; this is shown to be a neoclassical transport problem in the limit of a small number of circulating electrons. In this regime, the resistivity is substantially higher than the Spitzer resistivity due to the magnetic trapping of a majority of the electrons. This suggests that heating the outer flux surfaces of the plasma with low-frequency parallel electric fields can be substantially more efficient than might be naively estimated. Such a skin-current heating scheme is analyzed by deriving an equation for diffusion of skin currents into the plasma, from which quantities such as the resistive skin-depth, lumped-circuit impedance, and power deposited in the plasma can be estimated. Numerical estimates indicate that this may be a simple and efficient way to couple power into experiments in this geometry.

  1. Secretary Steven Chu Visits Princeton Plasma Physics Laboratory...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    said has been at the center of the intellectual birth and coming of age of plasma and fusion science. Discussing our need for scientists to address our country's energy issues,...

  2. Can we estimate plasma density in ICP driver through electrical parameters in RF circuit?

    SciTech Connect (OSTI)

    Bandyopadhyay, M. Sudhir, Dass Chakraborty, A.

    2015-04-08

    To avoid regular maintenance, invasive plasma diagnostics with probes are not included in the inductively coupled plasma (ICP) based ITER Neutral Beam (NB) source design. Even non-invasive probes like optical emission spectroscopic diagnostics are also not included in the present ITER NB design due to overall system design and interface issues. As a result, negative ion beam current through the extraction system in the ITER NB negative ion source is the only measurement which indicates plasma condition inside the ion source. However, beam current not only depends on the plasma condition near the extraction region but also on the perveance condition of the ion extractor system and negative ion stripping. Nevertheless, inductively coupled plasma production region (RF driver region) is placed at distance (∼ 30cm) from the extraction region. Due to that, some uncertainties are expected to be involved if one tries to link beam current with plasma properties inside the RF driver. Plasma characterization in source RF driver region is utmost necessary to maintain the optimum condition for source operation. In this paper, a method of plasma density estimation is described, based on density dependent plasma load calculation.

  3. A new method for determining the plasma electron density using optical frequency comb interferometer

    SciTech Connect (OSTI)

    Arakawa, Hiroyuki Tojo, Hiroshi; Sasao, Hajime; Kawano, Yasunori; Itami, Kiyoshi

    2014-04-15

    A new method of plasma electron density measurement using interferometric phases (fractional fringes) of an optical frequency comb interferometer is proposed. Using the characteristics of the optical frequency comb laser, high density measurement can be achieved without fringe counting errors. Simulations show that the short wavelength and wide wavelength range of the laser source and low noise in interferometric phases measurements are effective to reduce ambiguity of measured density.

  4. PPPL launches expanded new laboratory for research on the use of plasma to

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

    synthesize nanoparticles | Princeton Plasma Physics Lab launches expanded new laboratory for research on the use of plasma to synthesize nanoparticles By John Greenwald July 12, 2016 Tweet Widget Google Plus One Share on Facebook Inside the new nanolaboratory. Front and center from left: Philip Efthimion, head of the Plasma Science and Technology Department, Charles Gentile, lead engineer for the nanolab, and Yevgeny Raitses, principal investigator and head of the facility. Behind them are

  5. PPPL launches expanded new laboratory for research on the use of plasma to

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

    synthesize nanoparticles | Princeton Plasma Physics Lab launches expanded new laboratory for research on the use of plasma to synthesize nanoparticles By John Greenwald July 12, 2016 Tweet Widget Google Plus One Share on Facebook Inside the new nanolaboratory. Front and center from left: Philip Efthimion, head of the Plasma Science and Technology Department, Charles Gentile, lead engineer for the nanolab, and Yevgeny Raitses, principal investigator and head of the facility. Behind them are

  6. McComas named vice president for the Princeton Plasma Physics Laboratory |

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

    Princeton Plasma Physics Lab McComas named vice president for the Princeton Plasma Physics Laboratory By Karin Dienst , Princeton University Office of Communications February 10, 2016 Tweet Widget Google Plus One Share on Facebook David McComas (Photo by the Southwest Research Institute ) David McComas David McComas, an executive leader in managing various complex technical projects and programs, has been named vice president for the U.S. Department of Energy's Princeton Plasma Physics

  7. 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; Bulanov, Stepan S.; Schroeder, Carl B.; Esarey, Eric; Califano, Francesco; Pegoraro, Francesco

    2012-11-15

    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.

  8. At Princeton Plasma Physics Laboratory, buying small is a big win |

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

    Princeton Plasma Physics Lab At Princeton Plasma Physics Laboratory, buying small is a big win By Gale Scott May 23, 2011 Tweet Widget Google Plus One Share on Facebook When scientists at the U.S. Department of Energy's Princeton Plasma Physics Laboratory (PPPL) needed metal flanges for a specialized piece of equipment, Principal Buyer Arlene White could have ordered them from a range of major manufacturers. Instead, the $150,000 order went to Zenex Precision Products, a small, family-owned

  9. Center at plasma laboratory wins $12 million grant for fusion research |

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

    Princeton Plasma Physics Lab Center at plasma laboratory wins $12 million grant for fusion research By John Greenwald October 10, 2012 Tweet Widget Google Plus One Share on Facebook C.S. Chang, who heads the Center for Edge Physics Simulation at the Princeton Plasma Physics Lab, stands by a high-performance computer cluster at the laboratory. With a $12.25 million grant from the U.S. Department of Energy, Chang and other researchers will develop computer codes to simulate a key component of

  10. 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.

    2014-05-15

    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)

  11. Particle-in-cell simulations of collisionless shock formation via head-on merging of two laboratory supersonic plasma jets

    SciTech Connect (OSTI)

    Thoma, C.; Welch, D. R.; Hsu, S. C.

    2013-08-15

    We describe numerical simulations, using the particle-in-cell (PIC) and hybrid-PIC code lsp[T. P. Hughes et al., Phys. Rev. ST Accel. Beams 2, 110401 (1999)], of the head-on merging of two laboratory supersonic plasma jets. The goals of these experiments are to form and study astrophysically relevant collisionless shocks in the laboratory. Using the plasma jet initial conditions (density ?10{sup 14}10{sup 16} cm{sup ?3}, temperature ? few eV, and propagation speed ?20150 km/s), large-scale simulations of jet propagation demonstrate that interactions between the two jets are essentially collisionless at the merge region. In highly resolved one- and two-dimensional simulations, we show that collisionless shocks are generated by the merging jets when immersed in applied magnetic fields (B?0.11 T). At expected plasma jet speeds of up to 150 km/s, our simulations do not give rise to unmagnetized collisionless shocks, which require much higher velocities. The orientation of the magnetic field and the axial and transverse density gradients of the jets have a strong effect on the nature of the interaction. We compare some of our simulation results with those of previously published PIC simulation studies of collisionless shock formation.

  12. LOCALIZED PLASMA DENSITY ENHANCEMENTS OBSERVED IN STEREO COR1

    SciTech Connect (OSTI)

    Jones, Shaela I.; Davila, Joseph M.

    2009-08-20

    Measurements of solar wind speed in the solar corona, where it is primarily accelerated, have proven elusive. One of the more successful attempts has been the tracking of outward-moving density inhomogeneities in white-light coronagraph images. These inhomogeneities, or 'blobs', have been treated as passive tracers of the ambient solar wind. Here we report on the extension of these observations to lower altitudes using the STEREO COR1 coronagraph, and discuss the implications of these measurements for theories about the origin of these features.

  13. Impurities, temperature, and density in a miniature electrostatic plasma and current source

    SciTech Connect (OSTI)

    Den Hartog, D.J.; Craig, D.J.; Fiksel, G.; Sarff, J.S.

    1996-10-01

    We have spectroscopically investigated the Sterling Scientific miniature electrostatic plasma source-a plasma gun. This gun is a clean source of high density (10{sup 19} - 10{sup 20} m{sup -3}), low temperature (5 - 15 eV) plasma. A key result of our investigation is that molybdenum from the gun electrodes is largely trapped in the internal gun discharge; only a small amount escapes in the plasma flowing out of the gun. In addition, the gun plasma parameters actually improve (even lower impurity contamination and higher ion temperature) when up to 1 kA of electron current is extracted from the gun via the application of an external bias. This improvement occurs because the internal gun anode no longer acts as the current return for the internal gun discharge. The gun plasma is a virtual plasma electrode capable of sourcing an electron emission current density of 1 kA/cm{sup 2}. The high emission current, small size (3 - 4 cm diameter), and low impurity generation make this gun attractive for a variety of fusion and plasma technology applications.

  14. Theses - Publications - Center for Plasma in the Laboratory and

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

    These Tiny Capsules Fight Climate Change These Tiny Capsules Fight Climate Change May 17, 2016 - 5:21pm Addthis Watch to see how scientists make carbon capture microcapsules, which absorb CO2 before it enters the atmosphere. | Video by Lawrence Livermore National Laboratory. Anne M. Stark Senior Public Information Officer, Lawrence Livermore National Laboratory These capsules are tiny, but they promise to have a big impact in the fight against climate change. Using the same baking soda found in

  15. Investigation of physical processes limiting plasma density in H-mode on DIII-D

    SciTech Connect (OSTI)

    Maingi, R.; Mahdavi, M.A.; Jernigan, T.C.

    1996-12-01

    A series of experiments was conducted on the DIII-D tokamak to investigate the physical processes which limit density in high confinement mode (H-mode) discharges. The typical H-mode to low confinement mode (L-mode) transition limit at high density near the empirical Greenwald density limit was avoided by divertor pumping, which reduced divertor neutral pressure and prevented formation of a high density, intense radiation zone (MARFE) near the X-point. It was determined that the density decay time after pellet injection was independent of density relative to the Greenwald limit and increased non-linearly with the plasma current. Magnetohydrodynamic (MHD) activity in pellet-fueled plasmas was observed at all power levels, and often caused unacceptable confinement degradation, except when the neutral beam injected (NBI) power was {le} 3 MW. Formation of MARFEs on closed field lines was avoided with low safety factor (q) operation but was observed at high q, qualitatively consistent with theory. By using pellet fueling and optimizing discharge parameters to avoid each of these limits, an operational space was accessed in which density {approximately} 1.5 {times} Greenwald limit was achieved for 600 ms, and good H-mode confinement was maintained for 300 ms of the density flattop. More significantly, the density was successfully increased to the limit where a central radiative collapse was observed, the most fundamental density limit in tokamaks.

  16. Princeton University, Plasma Physics Laboratory annual report, October 1, 1988--September 30, 1989

    SciTech Connect (OSTI)

    Not Available

    1989-12-31

    This report contains discussions on the following topics: principal parameters achieved in experimental devices (FY89); tokamak fusion test reactor; compact ignition tokamak; princeton beta experiment- modification; current drive experiment; international collaboration; x-ray laser studies; spacecraft glow experiment; plasma 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 (FY89); graduate education: plasma physics; graduate education: plasma science and technology; and Princeton Plasmas Physics Laboratory Reports (FY89).

  17. Princeton University, Plasma Physics Laboratory annual report, October 1, 1988--September 30, 1989

    SciTech Connect (OSTI)

    Not Available

    1989-01-01

    This report contains discussions on the following topics: principal parameters achieved in experimental devices (FY89); tokamak fusion test reactor; compact ignition tokamak; princeton beta experiment- modification; current drive experiment; international collaboration; x-ray laser studies; spacecraft glow experiment; plasma 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 (FY89); graduate education: plasma physics; graduate education: plasma science and technology; and Princeton Plasmas Physics Laboratory Reports (FY89).

  18. Princeton Plasma Physics Laboratory. Annual report, October 1, 1989--September 30, 1990

    SciTech Connect (OSTI)

    Not Available

    1990-12-31

    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.

  19. Strong self-focusing of a cosh-Gaussian laser beam in collisionless magneto-plasma under plasma density ramp

    SciTech Connect (OSTI)

    Nanda, Vikas; Kant, Niti

    2014-07-15

    The effect of plasma density ramp on self-focusing of cosh-Gaussian laser beam considering ponderomotive nonlinearity is analyzed using WKB and paraxial approximation. It is noticed that cosh-Gaussian laser beam focused earlier than Gaussian beam. The focusing and de-focusing nature of the cosh-Gaussian laser beam with decentered parameter, intensity parameter, magnetic field, and relative density parameter has been studied and strong self-focusing is reported. It is investigated that decentered parameter “b” plays a significant role for the self-focusing of the laser beam as for b=2.12, strong self-focusing is seen. Further, it is observed that extraordinary mode is more prominent toward self-focusing rather than ordinary mode of propagation. For b=2.12, with the increase in the value of magnetic field self-focusing effect, in case of extraordinary mode, becomes very strong under plasma density ramp. Present study may be very useful in the applications like the generation of inertial fusion energy driven by lasers, laser driven accelerators, and x-ray lasers. Moreover, plasma density ramp plays a vital role to enhance the self-focusing effect.

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

    SciTech Connect (OSTI)

    Sati, Priti; Tripathi, V. K.

    2012-12-15

    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.

  1. Effect of the resonant growth of harmonics on the electron density in capacitively coupled plasma

    SciTech Connect (OSTI)

    Yamazawa, Yohei

    2009-11-09

    The growth of harmonics is known to occur under the condition of plasma series resonance (PSR). In an actual plasma process chamber, the external circuit also affects the PSR. We experimentally demonstrated the resonant growth of the third and fourth harmonics by tuning a variable capacitor attached to the electrode, and investigated the influence of the growth on the electron density. We observed significant increases in electron density as the amplitude of harmonics grows. The result clearly shows that nonlinear electron resonance heating actually takes place.

  2. Effect of trapped electrons on soliton propagation in a plasma having a density gradient

    SciTech Connect (OSTI)

    Aziz, Farah; Stroth, Ulrich

    2009-03-15

    A Korteweg-deVries equation with an additional term due to the density gradient is obtained using reductive perturbation technique in an unmagnetized plasma having a density gradient, finite temperature ions, and two-temperature nonisothermal (trapped) electrons. This equation is solved to get the solitary wave solution using sine-cosine method. The phase velocity, soliton amplitude, and width are examined under the effect of electron and ion temperatures and their concentrations. The effect of ion (electron) temperature is found to be more significant in the presence of larger (smaller) number of trapped electrons in the plasma.

  3. Critical density for Landau damping in a two-electron-component plasma

    SciTech Connect (OSTI)

    Rupp, Constantin F.; López, Rodrigo A.; Araneda, Jaime A.

    2015-10-15

    The asymptotic evolution of an initial perturbation in a collisionless two-electron-component plasma with different temperatures is studied numerically. The transition between linear and nonlinear damping regimes is determined by slowly varying the density of the secondary electron-component using high-resolution Vlasov-Poisson simulations. It is shown that, for fixed amplitude perturbations, this transition behaves as a critical phenomenon with time scales and field amplitudes exhibiting power-law dependencies on the threshold density, similar to the critical amplitude behavior in a single-component plasma.

  4. Development of high-density helicon plasma sources and their applications

    SciTech Connect (OSTI)

    Shinohara, Shunjiro; Hada, Tohru; Motomura, Taisei; Tanaka, Kenji; Tanikawa, Takao; Toki, Kyoichiro; Tanaka, Yoshikazu; Shamrai, Konstantin P.

    2009-05-15

    We report on the development of unique, high-density helicon plasma sources and describe their applications. Characterization of one of the largest helicon plasma sources yet constructed is made. Scalings of the particle production efficiency are derived from various plasma production devices in open literature and our own data from long and short cylinder devices, i.e., high and low values of the aspect ratio A (the ratio of the axial length to the diameter), considering the power balance in the framework of a simple diffusion model. A high plasma production efficiency is demonstrated, and we clarify the structures of the excited waves in the low A region down to 0.075 (the large device diameter of 73.8 cm with the axial length as short as 5.5 cm). We describe the application to plasma propulsion using a new concept that employs no electrodes. A very small diameter (2.5 cm) helicon plasma with 10{sup 13} cm{sup -3} density is produced, and the preliminary results of electromagnetic plasma acceleration are briefly described.

  5. Inhomogeneities of plasma density and electric field as sources of electrostatic turbulence in the auroral region

    SciTech Connect (OSTI)

    Ilyasov, Askar A.; Chernyshov, Alexander A. Mogilevsky, Mikhail M.; Golovchanskaya, Irina V. Kozelov, Boris V.

    2015-03-15

    Inhomogeneities of plasma density and non-uniform electric fields are compared as possible sources of a sort of electrostatic ion cyclotron waves that can be identified with broadband extremely low frequency electrostatic turbulence in the topside auroral ionosphere. Such waves are excited by inhomogeneous energy-density-driven instability. To gain a deeper insight in generation of these waves, computational modeling is performed with various plasma parameters. It is demonstrated that inhomogeneities of plasma density can give rise to this instability even in the absence of electric fields. By using both satellite-observed and model spatial distributions of plasma density and electric field in our modeling, we show that specific details of the spatial distributions are of minor importance for the wave generation. The solutions of the nonlocal inhomogeneous energy-density-driven dispersion relation are investigated for various ion-to-electron temperature ratios and directions of wave propagation. The relevance of the solutions to the observed spectra of broadband extremely low frequency emissions is shown.

  6. Power balance in a high-density field reversed configuration plasma

    SciTech Connect (OSTI)

    Renneke, R. M.; Intrator, T. P.; Hsu, S. C.; Wurden, G. A.; Waganaar, W. J.; Ruden, E. L.; Grabowski, T. C.

    2008-06-15

    A global power balance analysis has been performed for the Field Reversed Experiment with Liner high density (>5x10{sup 22} m{sup -3}) field reversed configuration (FRC) plasma. The analysis was based on a zero-dimensional power balance model [D. J. Rey and M. Tuszewski, Phys. Fluids 27, 1514 (1984)]. The key findings are as follows. First, the percentage of radiative losses relative to total loss is an order of magnitude lower than previous lower density FRC experiments. Second, Ohmic heating was found to correlate with the poloidal flux trapping at FRC formation, suggesting that poloidal flux dissipation is primarily responsible for plasma heating. Third, high density FRCs analyzed in this work reinforce the low-density adiabatic scaling, which shows that particle confinement time and flux confinement time are approximately equal.

  7. Theory of discrete dynamo activity in laboratory plasmas: RFP sawteeth

    SciTech Connect (OSTI)

    Hegna, C.C.; Prager, S.C.; Gimblett, C.G.

    1996-12-31

    Reversed field pinch experiments (RFP) exhibit relaxation phenomena which sustain the magnetic configuration longer than electrical resistivity should allow. This effect is due to the NMD dynamo. An interesting feature of the dynamo is that the relaxations often occur in a discrete and nearly periodic sawtoothing fashion. Unlike the tokamak sawtooth where a single Fourier harmonic is believed to play a central role in the sawtooth dynamics, RFP sawteeth are characterized by a set of tearing instabilities which play the essential role in the MHD dynamo. A theoretical explanation of the discrete dynamo is presented which is based upon a description of the RFP dynamics as a low order dynamical system. The calculation accounts for the evolution of the equilibrium that is affected by applied electrical fields, diffusion processes and the MHD dynamo, as well as a dynamical description of the MHD dynamo which is determined from the behavior of the tearing instabilities and the properties of the equilibrium. The system can be reduced to two ordinary differential equations for the averaged current gradient, which measures the degree of plasma relaxation, and the dynamo amplitude. The dynamical system exhibit a predator-prey type periodic limit cycle, which is characterized by a slow current peaking phase followed by a rapid crash. The sawtooth amplitude and period are predicted to increase with Lundquist number and plasma current, features which are in qualitative agreement with experimental observations.

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

    SciTech Connect (OSTI)

    Lebedev, S. V. 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.; Burgess, D.; Clemens, A.; Ciardi, A.; Sheng, L.; Yuan, J.; and others

    2014-05-15

    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/ω{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.

  9. Multispecies density peaking in gyrokinetic turbulence simulations of low collisionality Alcator C-Mod plasmas

    SciTech Connect (OSTI)

    Mikkelsen, D. R. Bitter, M.; Delgado-Aparicio, L.; Hill, K. W.; Greenwald, M.; Howard, N. T.; Hughes, J. W.; Rice, J. E.; Reinke, M. L.; Podpaly, Y.; Ma, Y.; Candy, J.; Waltz, R. E.

    2015-06-15

    Peaked density profiles in low-collisionality AUG and JET H-mode plasmas are probably caused by a turbulently driven particle pinch, and Alcator C-Mod experiments confirmed that collisionality is a critical parameter. Density peaking in reactors could produce a number of important effects, some beneficial, such as enhanced fusion power and transport of fuel ions from the edge to the core, while others are undesirable, such as lower beta limits, reduced radiation from the plasma edge, and consequently higher divertor heat loads. Fundamental understanding of the pinch will enable planning to optimize these impacts. We show that density peaking is predicted by nonlinear gyrokinetic turbulence simulations based on measured profile data from low collisionality H-mode plasma in Alcator C-Mod. Multiple ion species are included to determine whether hydrogenic density peaking has an isotope dependence or is influenced by typical levels of low-Z impurities, and whether impurity density peaking depends on the species. We find that the deuterium density profile is slightly more peaked than that of hydrogen, and that experimentally relevant levels of boron have no appreciable effect on hydrogenic density peaking. The ratio of density at r/a = 0.44 to that at r/a = 0.74 is 1.2 for the majority D and minority H ions (and for electrons), and increases with impurity Z: 1.1 for helium, 1.15 for boron, 1.3 for neon, 1.4 for argon, and 1.5 for molybdenum. The ion temperature profile is varied to match better the predicted heat flux with the experimental transport analysis, but the resulting factor of two change in heat transport has only a weak effect on the predicted density peaking.

  10. 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)

    2012-07-15

    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.

  11. Scattering of electromagnetic waves by vortex density structures associated with interchange instability: Analytical and large scale plasma simulation results

    SciTech Connect (OSTI)

    Sotnikov, V.; Kim, T.; Lundberg, J.; Paraschiv, I.; Mehlhorn, T. A.

    2014-05-15

    The presence of plasma turbulence can strongly influence propagation properties of electromagnetic signals used for surveillance and communication. In particular, we are interested in the generation of low frequency plasma density irregularities in the form of coherent vortex structures. Interchange or flute type density irregularities in magnetized plasma are associated with Rayleigh-Taylor type instability. These types of density irregularities play an important role in refraction and scattering of high frequency electromagnetic signals propagating in the earth ionosphere, in high energy density physics, and in many other applications. We will discuss scattering of high frequency electromagnetic waves on low frequency density irregularities due to the presence of vortex density structures associated with interchange instability. We will also present particle-in-cell simulation results of electromagnetic scattering on vortex type density structures using the large scale plasma code LSP and compare them with analytical results.

  12. 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; Kim, Kihong

    2013-12-15

    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.

  13. Observation of plasma density dependence of electromagnetic soliton excitation by an intense laser pulse

    SciTech Connect (OSTI)

    Sarri, G.; Kar, S.; Kourakis, I.; Borghesi, M.; Romagnani, L.; Bulanov, S. V.; Cecchetti, C. A.; Gizzi, L. A.; Galimberti, M.; Heathcote, R.; Jung, R.; Osterholz, J.; Willi, O.; Schiavi, A.

    2011-08-15

    The experimental evidence of the correlation between the initial electron density of the plasma and electromagnetic soliton excitation at the wake of an intense (10{sup 19} W/cm{sup 2}) and short (1 ps) laser pulse is presented. The spatial distribution of the solitons, together with their late time evolution into post-solitons, is found to be dependent upon the background plasma parameters, in agreement with published analytical and numerical findings. The measured temporal evolution and electrostatic field distribution of the structures are consistent with their late time evolution and the occurrence of multiple merging of neighboring post-solitons.

  14. Modelling of the internal dynamics and density in a tens of joules plasma focus device

    SciTech Connect (OSTI)

    Marquez, Ariel; Gonzalez, Jose; Tarifeno-Saldivia, Ariel; Pavez, Cristian; Soto, Leopoldo; Clausse, Alejandro

    2012-01-15

    Using MHD theory, coupled differential equations were generated using a lumped parameter model to describe the internal behaviour of the pinch compression phase in plasma focus discharges. In order to provide these equations with appropriate initial conditions, the modelling of previous phases was included by describing the plasma sheath as planar shockwaves. The equations were solved numerically, and the results were contrasted against experimental measurements performed on the device PF-50J. The model is able to predict satisfactorily the timing and the radial electron density profile at the maximum compression.

  15. Simulation Study of an Extended Density DC Glow Toroidal Plasma Source

    SciTech Connect (OSTI)

    Granda-Gutierrez, E. E.; Piedad-Beneitez, A. de la; Lopez-Callejas, R.; Godoy-Cabrera, O. G.; Benitez-Read, J. S.; Pacheco-Sotelo, J. O.; Pena-Eguiluz, R.; Mercado-Cabrera, A.; Valencia A, R.; Barocio, S. R.

    2006-12-04

    Conventional wisdom assigns the DC glow discharge regime to plasma currents below {approx}500 mA values, beyond which the discharge falls into the anomalous glow and the turbulent arc regimes. However, we have found evidence that, during toroidal discharges, this barrier can be ostensibly extended up to 800 mA. Thus, a computer simulation has been applied to the evolution of the main electrical characteristics of such a glow discharge plasma in a toroidal vessel in order to design and construct a respective voltage/current controlled source. This should be able to generate a DC plasma in the glow regime with which currents in the range 10-3-100 A can be experimented and 109-1010 cm-3 plasma densities can be achieved to PIII optimization purposes. The plasma is modelled as a voltage-controlled current source able to be turned on whenever the breakdown voltage is reached across the gap between the anode and the vessel wall. The simulation outcome fits well our experimental measurements showing that the plasma current obeys power laws that are dependent on the power current and other control variables such as the gas pressure.

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

    SciTech Connect (OSTI)

    Cooper, C. M.; Brookhart, M.; Collins, C.; Khalzov, I.; Milhone, J.; Nornberg, M.; Weisberg, D.; Forest, C. B. [Department of Physics, University of Wisconsin, Madison, Wisconsin 53706 (United States) [Department of Physics, University of Wisconsin, Madison, Wisconsin 53706 (United States); Center for Magnetic Self Organization, University of Wisconsin, Madison, Wisconsin 53706 (United States); Wallace, J.; Clark, M.; Flanagan, K.; Li, Y.; Nonn, P. [Department of Physics, University of Wisconsin, Madison, Wisconsin 53706 (United States)] [Department of Physics, University of Wisconsin, Madison, Wisconsin 53706 (United States); Ding, W. X. [Department of Physics and Astronomy, University of California, Los Angeles, Los Angeles, California 90024 (United States)] [Department of Physics and Astronomy, University of California, Los Angeles, Los Angeles, California 90024 (United States); Whyte, D. G. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)] [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Zweibel, E. [Department of Physics, University of Wisconsin, Madison, Wisconsin 53706 (United States) [Department of Physics, University of Wisconsin, Madison, Wisconsin 53706 (United States); Center for Magnetic Self Organization, University of Wisconsin, Madison, Wisconsin 53706 (United States); Department of Astronomy, University of Wisconsin, Madison, Wisconsin 53706 (United States)

    2014-01-15

    The Madison plasma dynamo experiment (MPDX) is a novel, versatile, basic plasma research device designed to investigate flow driven magnetohydrodynamic instabilities and other high-? phenomena with astrophysically relevant parameters. A 3?m diameter vacuum vessel is lined with 36 rings of alternately oriented 4000?G samarium cobalt magnets, which create an axisymmetric multicusp that contains ?14 m{sup 3} of nearly magnetic field free plasma that is well confined and highly ionized (>50%). At present, 8 lanthanum hexaboride (LaB{sub 6}) cathodes and 10 molybdenum anodes are inserted into the vessel and biased up to 500?V, drawing 40?A each cathode, ionizing a low pressure Ar or He fill gas and heating it. Up to 100?kW of electron cyclotron heating power is planned for additional electron heating. The LaB{sub 6} cathodes are positioned in the magnetized edge to drive toroidal rotation through J??B torques that propagate into the unmagnetized core plasma. Dynamo studies on MPDX require a high magnetic Reynolds number Rm?>?1000, and an adjustable fluid Reynolds number 10?1). Initial results from MPDX are presented along with a 0-dimensional power and particle balance model to predict the viscosity and resistivity to achieve dynamo action.

  17. Conversion of magnetic energy in the magnetic reconnection layer of a laboratory plasma

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Yamada, Masaaki; Yoo, Jongsoo; Jara-Almonte, Jonathan; Ji, Hantao; Kulsrud, Russell M.; Myers, Clayton E.

    2014-09-10

    Magnetic reconnection, in which magnetic field lines break and reconnect to change their topology, occurs throughout the universe. The essential feature of reconnection is that it energizes plasma particles by converting magnetic energy. Despite the long history of reconnection research, how this energy conversion occurs remains a major unresolved problem in plasma physics. Here we report that the energy conversion in a laboratory reconnection layer occurs in a much larger region than previously considered. The mechanisms for energizing plasma particles in the reconnection layer are identified, and a quantitative inventory of the converted energy is presented for the first timemore » in a well defined reconnection layer; 50% of the magnetic energy is converted to particle energy, 2/3 of which transferred to ions and 1/3 to electrons. Our results are compared with simulations and space measurements, for a key step toward resolving one of the most important problems in plasma physics.« less

  18. Conversion of magnetic energy in the magnetic reconnection layer of a laboratory plasma

    SciTech Connect (OSTI)

    Yamada, Masaaki; Yoo, Jongsoo; Jara-Almonte, Jonathan; Ji, Hantao; Kulsrud, Russell M.; Myers, Clayton E.

    2014-09-10

    Magnetic reconnection, in which magnetic field lines break and reconnect to change their topology, occurs throughout the universe. The essential feature of reconnection is that it energizes plasma particles by converting magnetic energy. Despite the long history of reconnection research, how this energy conversion occurs remains a major unresolved problem in plasma physics. Here we report that the energy conversion in a laboratory reconnection layer occurs in a much larger region than previously considered. The mechanisms for energizing plasma particles in the reconnection layer are identified, and a quantitative inventory of the converted energy is presented for the first time in a well defined reconnection layer; 50% of the magnetic energy is converted to particle energy, 2/3 of which transferred to ions and 1/3 to electrons. Our results are compared with simulations and space measurements, for a key step toward resolving one of the most important problems in plasma physics.

  19. High-Density Plasma Arc Heating Studies of FePt Thin Films

    SciTech Connect (OSTI)

    Cole, Amanda C; Thompson, Gregory; Harrell, J. W.; Weston, James; Ott, Ronald D

    2006-01-01

    The effect of pulsed-thermal-processing with high-density plasma arc heating is discussed for 20 nm thick nanocrystalline FePt thin films. The dependence of the A1 {yields} L1{sub 0} phase transformation on pulsed time and radiant energy of the pulse is quantified through x-ray diffraction and alternating gradient magnetometry. For 100 ms and 250 ms pulse widths, the phase transformation was observed. Higher radiant energy densities resulted in a larger measured coercivity associated with the L1{sub 0} phase.

  20. The response of plasma density to breaking inertial gravity wave in the lower regions of ionosphere

    SciTech Connect (OSTI)

    Tang, Wenbo Mahalov, Alex

    2014-04-15

    We present a three-dimensional numerical study for the E and lower F region ionosphere coupled with the neutral atmosphere dynamics. This model is developed based on a previous ionospheric model that examines the transport patterns of plasma density given a prescribed neutral atmospheric flow. Inclusion of neutral dynamics in the model allows us to examine the charge-neutral interactions over the full evolution cycle of an inertial gravity wave when the background flow spins up from rest, saturates and eventually breaks. Using Lagrangian analyses, we show the mixing patterns of the ionospheric responses and the formation of ionospheric layers. The corresponding plasma density in this flow develops complex wave structures and small-scale patches during the gravity wave breaking event.

  1. 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)

    2014-02-24

    The electron-atom neutral bremsstrahlung continuum radiation emitted from weakly ionized plasmas is investigated for electron density and temperature diagnostics. The continuum spectrum in 4501000?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 280450?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.

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

    SciTech Connect (OSTI)

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

    1996-07-01

    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.

  3. A new method for determining the plasma electron density using three-color interferometer

    SciTech Connect (OSTI)

    Arakawa, Hiroyuki; Kawano, Yasunori; Itami, Kiyoshi

    2012-06-15

    A new method for determining the plasma electron density using the fractional fringes on three-color interferometer is proposed. Integrated phase shift on each interferometer is derived without using the temporal history of the fractional fringes. The dependence on the fringe resolution and the electrical noise are simulated on the wavelengths of CO{sub 2} laser. Short-time integrations of the fractional fringes enhance the reliability of this method.

  4. A laboratory study of asymmetric magnetic reconnection in strongly-driven plasmas

    SciTech Connect (OSTI)

    Rosenberg, M. J.; Li, C. K.; Fox, W.; Igumenshchev, I.; Seguin, F. H.; Town, R.P. J.; Frenje, J. A.; Stoeckl, C.; Glebov, V.; Petrasso, R. D.

    2015-02-04

    Magnetic reconnection, the annihilation and rearrangement of magnetic fields in a plasma, is a universal phenomenon that frequently occurs when plasmas carrying oppositely-directed field lines collide. In most natural circumstances the collision is asymmetric (the two plasmas having different properties), but laboratory research to date has been limited to symmetric configurations. Additionally, the regime of strongly-driven magnetic reconnection, where the ram pressure of the plasma dominates the magnetic pressure, as in several astrophysical environments, has also received little experimental attention. Thus, we have designed experiments to probe reconnection in asymmetric, strongly-driven, laser-generated plasmas. Here we show that, in this strongly-driven system, the rate of magnetic flux annihilation is dictated by the relative flow velocities of the opposing plasmas and is insensitive to initial asymmetries. Additionally, out-of-plane magnetic fields that arise from asymmetries in the three-dimensional plasma geometry have minimal impact on the reconnection rate, due to the strong flows.

  5. A laboratory study of asymmetric magnetic reconnection in strongly-driven plasmas

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Rosenberg, M. J.; Li, C. K.; Fox, W.; Igumenshchev, I.; Seguin, F. H.; Town, R.P. J.; Frenje, J. A.; Stoeckl, C.; Glebov, V.; Petrasso, R. D.

    2015-02-04

    Magnetic reconnection, the annihilation and rearrangement of magnetic fields in a plasma, is a universal phenomenon that frequently occurs when plasmas carrying oppositely-directed field lines collide. In most natural circumstances the collision is asymmetric (the two plasmas having different properties), but laboratory research to date has been limited to symmetric configurations. Additionally, the regime of strongly-driven magnetic reconnection, where the ram pressure of the plasma dominates the magnetic pressure, as in several astrophysical environments, has also received little experimental attention. Thus, we have designed experiments to probe reconnection in asymmetric, strongly-driven, laser-generated plasmas. Here we show that, in this strongly-drivenmore » system, the rate of magnetic flux annihilation is dictated by the relative flow velocities of the opposing plasmas and is insensitive to initial asymmetries. Additionally, out-of-plane magnetic fields that arise from asymmetries in the three-dimensional plasma geometry have minimal impact on the reconnection rate, due to the strong flows.« less

  6. Spectroscopic observation of simultaneous bi-directional reconnection outflows in a laboratory plasma

    SciTech Connect (OSTI)

    Brown, M. R.; Cothran, C. D.; Gray, T.; Myers, C. E.; Belova, E. V.

    2012-08-15

    We report a precise, direct spectroscopic measurement of simultaneous bi-directional outflows from a reconnection event in a laboratory plasma. Outflow speeds are as Alfvenic and Abel analysis shows that the outflows are generated in the plasma core. A Sweet-Parker like analysis of outflow speed coupled with external measurements of reconnection electric field and assumption of Spitzer resistivity predict an aspect ratio of the reconnection layer and reconnection rate that are close to that measured in the experiment and in simulations. However, this analysis underestimates the absolute scale of the layer, indicating other than 2D resistive physics is at play.

  7. Fast magnetic reconnection in low-density electron-positron plasmas

    SciTech Connect (OSTI)

    Bessho, Naoki; Bhattacharjee, A.

    2010-10-15

    Two-dimensional particle-in-cell simulations have been performed to study magnetic reconnection in low-density electron-positron plasmas without a guide magnetic field. Impulsive reconnection rates become of the order of unity when the background density is much smaller than 10% of the density in the initial current layer. It is demonstrated that the outflow speed is less than the upstream Alfven speed, and that the time derivative of the density must be taken into account in the definition of the reconnection rate. The reconnection electric fields in the low-density regime become much larger than the ones in the high-density regime, and it is possible to accelerate the particles to high energies more efficiently. The inertial term in the generalized Ohm's law is the most dominant term that supports a large reconnection electric field. An effective collisionless resistivity is produced and tracks the extension of the diffusion region in the late stage of the reconnection dynamics, and significant broadening of the diffusion region is observed. Because of the broadening of the diffusion region, no secondary islands, which have been considered to play a role to limit the diffusion region, are generated during the extension of the diffusion region in the outflow direction.

  8. Laboratory measurements of resistivity in warm dense plasmas relevant to the microphysics of brown dwarfs

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Booth, N.; Robinson, A. P. L.; Hakel, P.; Clarke, R. J.; Dance, R. J.; Doria, D.; Gizzi, L. A.; Gregori, G.; Koester, P.; Labate, L.; et al

    2015-11-06

    Since the observation of the first brown dwarf in 1995, numerous studies have led to a better understanding of the structures of these objects. Here we present a method for studying material resistivity in warm dense plasmas in the laboratory, which we relate to the microphysics of brown dwarfs through viscosity and electron collisions. Here we use X-ray polarimetry to determine the resistivity of a sulphur-doped plastic target heated to Brown Dwarf conditions by an ultra-intense laser. The resistivity is determined by matching the plasma physics model to the atomic physics calculations of the measured large, positive, polarization. Furthermore, themore » inferred resistivity is larger than predicted using standard resistivity models, suggesting that these commonly used models will not adequately describe the resistivity of warm dense plasma related to the viscosity of brown dwarfs.« less

  9. Laboratory measurements of resistivity in warm dense plasmas relevant to the microphysics of brown dwarfs

    SciTech Connect (OSTI)

    Booth, N.; Robinson, A. P. L.; Hakel, P.; Clarke, R. J.; Dance, R. J.; Doria, D.; Gizzi, L. A.; Gregori, G.; Koester, P.; Labate, L.; Levato, T.; Li, B.; Makita, M.; Mancini, R. C.; Pasley, J.; Rajeev, P. P.; Riley, D.; Wagenaars, E.; Waugh, J. N.; Woolsey, N. C.

    2015-11-06

    Since the observation of the first brown dwarf in 1995, numerous studies have led to a better understanding of the structures of these objects. Here we present a method for studying material resistivity in warm dense plasmas in the laboratory, which we relate to the microphysics of brown dwarfs through viscosity and electron collisions. Here we use X-ray polarimetry to determine the resistivity of a sulphur-doped plastic target heated to Brown Dwarf conditions by an ultra-intense laser. The resistivity is determined by matching the plasma physics model to the atomic physics calculations of the measured large, positive, polarization. Furthermore, the inferred resistivity is larger than predicted using standard resistivity models, suggesting that these commonly used models will not adequately describe the resistivity of warm dense plasma related to the viscosity of brown dwarfs.

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

    SciTech Connect (OSTI)

    Chen, Hui E-mail: bitter@pppl.gov; Magee, E.; Nagel, S. R.; Park, J.; Schneider, M. B.; Stone, G.; Williams, G. J.; Beiersdorfer, P.; Bitter, M. E-mail: bitter@pppl.gov; Hill, K. W.; Kerr, S.

    2014-11-15

    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.

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

    SciTech Connect (OSTI)

    Lin, M.-W.; Jovanovic, I.

    2012-11-15

    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. Plasma

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

    confinement by circularly polarized electromagnetic field in toroidal geometry Vladimir A. Svidzinski University of Wisconsin-Madison, Madison, Wisconsin 53706, USA and Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA ͑Received 21 May 2007; accepted 2 July 2007; published online 31 October 2007͒ A novel plasma confinement concept based on plasma confinement by electromagnetic pressure of circularly polarized electromagnetic fields is proposed. Practical implementation of this

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

    SciTech Connect (OSTI)

    Shahid, M.; Hussain, A.; Department of Physics, Government College University, Lahore-54000 ; Murtaza, G.

    2013-09-15

    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.

  14. Analysis of plasma density profiles and thermal transport in laser-irradiated spherical targets

    SciTech Connect (OSTI)

    Fechner, W.B.; Shepard, C.L.; Busch, G.E.; Schroeder, R.J.; Tarvin, J.A.

    1984-06-01

    Measurements are presented for plasma density profiles, critical surface trajectories, and mass-ablation rates, as obtained from experiments in which layered spherical targets were irradiated with 1.05-..mu..m laser light at intensities between 1 x 10/sup 14/ and 1 x 10/sup 15/ W/cm/sup 2/. The targets were designed to allow study of thermal transport in overdense plasmas. They were from 70 to 110 ..mu..m in diameter, with a variable thickness parylene ablator and an aluminum substrate. Simulated results are consistent with all three sets of data if transport of both thermal and suprathermal electrons is severely inhibited, with a flux limiter of 0.03< or =f< or =0.06 being appropriate.

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

    DOE Patents [OSTI]

    Thode, Lester E.

    1981-01-01

    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.

  16. Measurement of electron density in complex plasmas of the PK-3 plus apparatus on the International Space Station

    SciTech Connect (OSTI)

    Takahashi, Kazuo; Hayashi, Yasuaki; Adachi, Satoshi

    2011-07-01

    Dust particles in discharge are often levitated in a sheath region rather than in bulk plasma under gravitational conditions (on Earth). Gravity compresses dust clouds, and the gravitational force restricts the motion of the dust particles. Microgravity gives the plasmas, including dust particles, so-called complex (dusty) plasmas, where dust particles are embedded in a completely charge-neutral region of the bulk plasma. The dust cloud, as an uncompressed strongly-coupled Coulomb system, corresponds to an atomic model with physical phenomena, e.g., crystallization, phase transition, and so on. Since the phenomena are tightly connected to plasma states expressed by plasma parameters, it is significant to estimate the plasma parameters, such as electron density and temperature. The present work shows the electron density measured by the frequency shift probe in the apparatus for microgravity experiments currently boarding on the International Space Station (PK-3 plus). The frequency shift probe measurement gave electron density in the order of 10{sup 8} cm{sup -3} as a typical value in the apparatus, and demonstrated the detection of electrons in plasmas with dust particles. The spatial distribution profile of the electron density obtained in this measurement presents an aspect for the void formation of dust clouds under microgravity.

  17. Plasma-Surface Interaction Research At The Cambridge Laboratory Of Accelerator Studies Of Surfaces

    SciTech Connect (OSTI)

    Wright, G. M.; Barnard, H. S.; Hartwig, Z. S.; Stahle, P. W.; Sullivan, R. M.; Woller, K. B.; Whyte, D. G.

    2011-06-01

    The material requirements for plasma-facing components in a nuclear fusion reactor are some of the strictest and most challenging facing us today. These materials are simultaneously exposed to extreme heat loads (20 MW/m{sup 2} steady-state, 1 GW/m{sup 2} in millisecond transients) and particle fluxes (>10{sup 24} m{sup -2} s{sup -1}) while also undergoing high neutron irradiation (10{sup 18} neutrons/m{sup 2} s). At the Cambridge Laboratory of Accelerator Studies of Surfaces (CLASS), many of the most important issues in plasma-surface interaction research, such as plasma-driven material erosion and deposition, material transport and irradiation and hydrogenic retention are investigated with the use of a 1.7 MV tandem ion accelerator. Ion-Beam Analysis (IBA) is used to investigate and quantify changes in materials due to plasma exposure and ion irradiation is used as a proxy for neutron irradiation to investigate plasma-surface interactions for irradiated materials. This report will outline the capabilities and current research activities at CLASS.

  18. Analysis by oxygen atom number density measurement of high-speed hydrophilic treatment of polyimide using atmospheric pressure microwave plasma

    SciTech Connect (OSTI)

    Ono, S.

    2015-03-30

    This paper describes the fundamental experimental data of the plasma surface modification of the polyimide using atmospheric pressure microwave plasma source. The experimental results were discussed from the point of view of the radicals behavior, which significantly affects the modification mechanism. The purpose of the study is to examine how the value of the oxygen atom density will affect the hydrophilic treatment in the upstream region of the plasma where gas temperature is very high. The surface modification experiments were performed by setting the polyimide film sample in the downstream region of the plasma. The degree of the modification was measured by a water contact angle measurement. The water contact angle decreased less than 30 degrees within 1 second treatment time in the upstream region. Very high speed modification was observed. The reason of this high speed modification seems that the high density radical which contributes the surface modification exist in the upstream region of the plasma. This tendency is supposed to the measured relatively high electron density (~10{sup 15}cm{sup ?3}) at the center of the plasma. We used the electric heating catalytic probe method for oxygen radical measurement. An absolute value of oxygen radical density was determined by catalytic probe measurement and the results show that ~10{sup 15}cm{sup ?3} of the oxygen radical density in the upstream region and decreases toward downstream region. The experimental results of the relation of the oxygen radical density and hydrophilic modification of polyimide was discussed.

  19. Highly collimated monoenergetic target-surface electron acceleration in near-critical-density plasmas

    SciTech Connect (OSTI)

    Mao, J. Y.; Chen, L. M.; Huang, K.; Ma, Y.; Zhao, J. R.; Yan, W. C.; Ma, J. L.; Wei, Z. Y.; Li, D. Z.; Aeschlimann, M.; Zhang, J.

    2015-03-30

    Optimized-quality monoenergetic target surface electron beams at MeV level with low normalized emittance (0.03π mm mrad) and high charge (30 pC) per shot have been obtained from 3 TW laser-solid interactions at a grazing incidence. The 2-Dimension particle-in-cell simulations suggest that electrons are wake-field accelerated in a large-scale, near-critical-density preplasma. It reveals that a bubble-like structure as an accelerating cavity appears in the near-critical-density plasma region and travels along the target surface. A bunch of electrons are pinched transversely and accelerated longitudinally by the wake field in the bubble. The outstanding normalized emittance and monochromaticity of such highly collimated surface electron beams could make it an ideal beam for fast ignition or may serve as an injector in traditional accelerators.

  20. Low density gas and foam targets for ICF long scale length plasma experiments: Fabrication & characterization

    SciTech Connect (OSTI)

    Gobby, P.L.; Mitchell, M.A.; Eliott, N.E.; Salazar, M.A.; Fermandez, J.C.; Hsing, W.W.; Moore, J.E.; Gomez, V.M.

    1994-10-01

    Recent ICF experiments performed by the laser-matter interaction group at Los Alamos using the Nova laser to investigate long scale length plasmas required two types of special targets: gas-filled hohlraums and free-standing low density foams, both with densities in the range of 3-5 mg/cc. The mass in each case was provided by hydrogen and carbon - in the form of polymethylpentyene for the foam case and 2.2-dimethylpropane (i.e., neopentane, C{sub 5}H{sub 12}) at 1 atmosphere for the gas case. Dopants of Cl, Ti, Cr and Mn were added to the foams, while Ti and Cr coated carbon fibers were added to the hohlraums - both for isoelectronic x-ray spectroscopic temperature measurements.

  1. Measurements of ion stopping around the Bragg peak in high-energy-density plasmas

    SciTech Connect (OSTI)

    Frenje, J. A.; Grabowski, P. E.; Li, C. K.; Seguin, F. H.; Zylstra, A. B.; Gatu Johnson, M.; Petrasso, R. D.; Glebov, V. Yu; Sangster, T. C.

    2015-11-09

    For the first time, quantitative measurements of ion stopping at energies about the Bragg peak (or peak ion stopping, which occurs at an ion velocity comparable to the average thermal electron velocity), and its dependence on electron temperature (Te) and electron number density (ne) in the range of 0.5 – 4.0 keV and 3 × 1022 – 3 × 1023 cm-3 have been conducted, respectively. It is experimentally demonstrated that the position and amplitude of the Bragg peak varies strongly with Te with ne. As a result, the importance of including quantum diffraction is also demonstrated in the stopping-power modeling of High-Energy-Density Plasmas.

  2. Measurements of ion stopping around the Bragg peak in high-energy-density plasmas

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Frenje, J. A.; Grabowski, P. E.; Li, C. K.; Seguin, F. H.; Zylstra, A. B.; Gatu Johnson, M.; Petrasso, R. D.; Glebov, V. Yu; Sangster, T. C.

    2015-11-09

    For the first time, quantitative measurements of ion stopping at energies about the Bragg peak (or peak ion stopping, which occurs at an ion velocity comparable to the average thermal electron velocity), and its dependence on electron temperature (Te) and electron number density (ne) in the range of 0.5 – 4.0 keV and 3 × 1022 – 3 × 1023 cm-3 have been conducted, respectively. It is experimentally demonstrated that the position and amplitude of the Bragg peak varies strongly with Te with ne. As a result, the importance of including quantum diffraction is also demonstrated in the stopping-power modelingmore » of High-Energy-Density Plasmas.« less

  3. Transition from order to chaos, and density limit, in magnetized plasmas

    SciTech Connect (OSTI)

    Carati, A.; Maiocchi, A.; Marino, M.; Galgani, L.; Zuin, M.; Martines, E.

    2012-09-15

    It is known that a plasma in a magnetic field, conceived microscopically as a system of point charges, can exist in a magnetized state, and thus remain confined, inasmuch as it is in an ordered state of motion, with the charged particles performing gyrational motions transverse to the field. Here, we give an estimate of a threshold, beyond which transverse motions become chaotic, the electrons being unable to perform even one gyration, so that a breakdown should occur, with complete loss of confinement. The estimate is obtained by the methods of perturbation theory, taking as perturbing force acting on each electron that due to the so-called microfield, i.e., the electric field produced by all the other charges. We first obtain a general relation for the threshold, which involves the fluctuations of the microfield. Then, taking for such fluctuations, the formula given by Iglesias, Lebowitz, and MacGowan for the model of a one component plasma with neutralizing background, we obtain a definite formula for the threshold, which corresponds to a density limit increasing as the square of the imposed magnetic field. Such a theoretical density limit is found to fit pretty well the empirical data for collapses of fusion machines.

  4. Moiré deflectometry using the Talbot-Lau interferometer as refraction diagnostic for High Energy Density plasmas at energies below 10 keV

    SciTech Connect (OSTI)

    Valdivia, M. P.; Stutman, D.; Finkenthal, M.

    2014-07-15

    The highly localized density gradients expected in High Energy Density (HED) plasma experiments can be characterized by x-ray phase-contrast imaging in addition to conventional attenuation radiography. Moiré deflectometry using the Talbot-Lau grating interferometer setup is an attractive HED diagnostic due to its high sensitivity to refraction induced phase shifts. We report on the adaptation of such a system for operation in the sub-10 keV range by using a combination of free standing and ultrathin Talbot gratings. This new x-ray energy explored matches well the current x-ray backlighters used for HED experiments, while also enhancing phase effects at lower electron densities. We studied the performance of the high magnification, low energy Talbot-Lau interferometer, for single image phase retrieval using Moiré fringe deflectometry. Our laboratory and simulation studies indicate that such a device is able to retrieve object electron densities from phase shift measurements. Using laboratory x-ray sources from 7 to 15 μm size we obtained accurate simultaneous measurements of refraction and attenuation for both sharp and mild electron density gradients.

  5. Understanding the dramatic role of anomalous dispersion on the measurement of electron densities in plasmas using interferometers

    SciTech Connect (OSTI)

    Nilsen, J; Johnson, W R; Iglesias, C A; Scofield, J H

    2005-07-20

    For decades the electron density of plasmas has been measured using optical interferometers. With the availability of good X-ray laser sources in the last decade interferometers have been extended into the wavelength range 14-47 nm, which has enabled researchers to probe even higher density plasmas. The data analysis assumes the index of refraction is due only to the free electrons, which makes the index less than one. Recent interferometer experiments in Al plasmas observed plasmas with index of refraction greater than one at 14 nm and brought into question the validity of the usual formula for calculating the index. In this paper we show how the anomalous dispersion from bound electrons can dominate the free electron contribution to the index of refraction in many plasmas and make the index greater than one or enhance the contribution to the index such that one would greatly overestimate the density of the plasma using interferometers. Using a new average-atom code we calculate the index of refraction in many plasmas at different temperatures for photon energies from 0 to 100 eV and compare against calculations done with OPAL. We also present examples of other plasmas that may have index of refraction greater than one at X-ray laser energies. During the next decade X-ray free electron lasers and other X-ray sources will be available to probe a wider variety of plasmas at higher densities and shorter wavelengths so understanding the index of refraction in plasmas will be even more essential.

  6. Identification of the Electron Diffusion Region during Magnetic Reconnection in a Laboratory Plasma

    SciTech Connect (OSTI)

    Ren, Yang; Yamada, Masaaki; Ji, Hantao; Gerhardt, Stefan; Kulsrud, Russell

    2008-06-26

    We report the first identification of the electron diffusion region, where demagnetized electrons are accelerated to super-Alfvenic speed, in a reconnecting laboratory plasma. The electron diffusion region is determined from measurements of the out-of-plane quadrupole magnetic field in the neutral sheet in the Magnetic Reconnection Experiment. The width of the electron diffusion region scales with the electron skin depth (~ 5.5-7.5c=ωpi) and the peak electron outflow velocity scales with the electron Alfven velocity (~ 0.12 - 0.16VeA), independent of ion mass.

  7. Hanle effect as candidate for measuring magnetic fields in laboratory plasmas

    SciTech Connect (OSTI)

    Presura, R.

    2012-10-15

    Weak or turbulent magnetic fields are generally difficult to measure in laboratory plasmas. A new technique to address this problem may be based on the Hanle effect, used for magnetic field measurements in solar and stellar atmospheres. The effect consists in the modification of the polarization state of the resonance-line scattered radiation. It applies for magnetic field strengths for which the shift of magnetic sublevels remains comparable to the natural width of the sublevels. Experimental configurations and parameter ranges of applicability of a Hanle effect-based diagnostics technique are discussed.

  8. Princeton Plasma Physics Laboratory (PPPL) annual site environmental report for Calendar Year 1992

    SciTech Connect (OSTI)

    Finley, V.L.; Wieczorek, M.A.

    1994-03-01

    This report gives the results of the environmental activities and monitoring programs at the Princeton Plasma Physics Laboratory (PPPL) for CY92. The report is prepared to provide the US Department of Energy (DOE) and the public with information on the level of radioactive and nonradioactive pollutants, if any, added to the environment as a result of PPPL operations, as well as environmental initiatives, assessments, and programs. The objective of the Annual Site Environmental Report is to document evidence that DOE facility environmental protection programs adequately protect the environment and the public health.

  9. Note: Experimental platform for magnetized high-energy-density plasma studies at the omega laser facility

    SciTech Connect (OSTI)

    Fiksel, G.; Agliata, A.; Barnak, D.; Brent, G.; Chang, P. -Y.; Folnsbee, L.; Gates, G.; Hasset, D.; Lonobile, D.; Magoon, J.; Mastrosimone, D.; Shoup, III, M. J.; Betti, R.

    2015-01-12

    Here, an upgrade of the pulsed magnetic field generator magneto-inertial fusion electrical discharge system [O. Gotchev et al., Rev. Sci. Instrum. 80, 043504 (2009)] is described. The device is used to study magnetized high-energy-density plasma and is capable of producing a pulsed magnetic field of tens of tesla in a volume of a few cubic centimeters. The magnetic field is created by discharging a high-voltage capacitor through a small wire-wound coil. The coil current pulse has a duration of about 1 μs and a peak value of 40 kA. Compared to the original, the updated version has a larger energy storage and improved switching system. In addition, magnetic coils are fabricated using 3-D printing technology which allows for a greater variety of the magnetic field topology.

  10. Note: Experimental platform for magnetized high-energy-density plasma studies at the omega laser facility

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Fiksel, G.; Agliata, A.; Barnak, D.; Brent, G.; Chang, P. -Y.; Folnsbee, L.; Gates, G.; Hasset, D.; Lonobile, D.; Magoon, J.; et al

    2015-01-12

    Here, an upgrade of the pulsed magnetic field generator magneto-inertial fusion electrical discharge system [O. Gotchev et al., Rev. Sci. Instrum. 80, 043504 (2009)] is described. The device is used to study magnetized high-energy-density plasma and is capable of producing a pulsed magnetic field of tens of tesla in a volume of a few cubic centimeters. The magnetic field is created by discharging a high-voltage capacitor through a small wire-wound coil. The coil current pulse has a duration of about 1 μs and a peak value of 40 kA. Compared to the original, the updated version has a larger energymore » storage and improved switching system. In addition, magnetic coils are fabricated using 3-D printing technology which allows for a greater variety of the magnetic field topology.« less

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

    SciTech Connect (OSTI)

    Guan Nana; Li Jianwei; He Zejun; Long Jiali; Cai Xiangzhou; Ma Yugang; Shen Wenqing

    2009-07-15

    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: qq{yields}ll, qq{yields}gll, Compton-like scattering (qg{yields}qll,qg{yields}qll), gluon fusion (gg{yields}cc), annihilation (qq{yields}cc), 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. Magnetic reconnection in high-energy-density laser-produced plasmas

    SciTech Connect (OSTI)

    Fox, W.; Bhattacharjee, A.; Germaschewski, K.

    2012-05-15

    Recently, novel experiments on magnetic reconnection have been conducted in laser-produced plasmas in a high-energy-density regime. Individual plasma bubbles self-generate toroidal, mega-gauss-scale magnetic fields through the Biermann battery effect. When multiple bubbles are created at small separation, they expand into one another, driving reconnection of this field. Reconnection in the experiments was reported to be much faster than allowed by both Sweet-Parker, and even Hall-MHD theories, when normalized to the nominal magnetic fields self-generated by single bubbles. Through particle-in-cell simulations (both with and without a binary collision operator), we model the bubble interaction at parameters and geometry relevant to the experiments. This paper discusses in detail the reconnection regime of the laser-driven experiments and reports the qualitative features of simulations. We find substantial flux-pileup effects, which boost the relevant magnetic field for reconnection in the current sheet. When this is accounted for, the normalized reconnection rates are much more in line with standard two-fluid theory of reconnection. At the largest system sizes, we additionally find that the current sheet is prone to breakup into plasmoids.

  13. Princeton Plasma Physics Laboratory Annual Site Environmental Report for Calendar Year 2000

    SciTech Connect (OSTI)

    Virginia L. Finley

    2002-04-22

    The results of the 2000 environmental surveillance and monitoring program for the Princeton Plasma Physics Laboratory (PPPL) are presented and discussed. The purpose of this report is to provide the U.S. Department of Energy and the public with information on the level of radioactive and nonradioactive pollutants (if any) that are added to the environment as a result of PPPL's operations. The report also summarizes environmental initiatives, assessments, and programs that were undertaken in 2000. The Princeton Plasma Physics Laboratory has engaged in fusion energy research since 1951. The long-range goal of the U.S. Magnetic Fusion Energy Research Program is to create innovations to make fusion power a practical reality -- an alternative energy source. The year 2000 marked the second year of National Spherical Torus Experiment (NSTX) operations and Tokamak Fusion Test Reactor (TFTR) dismantlement and deconstruction activities. A collaboration among fourteen national laboratories, universities, and research institutions, the NSTX is a major element in the U.S. Fusion Energy Sciences Program. It has been designed to test the physics principles of spherical torus (ST) plasmas. The ST concept could play an important role in the development of smaller, more economical fusion power plants. With its completion within budget and ahead of its target schedule, NSTX first plasma occurred on February 12, 1999. In 2000, PPPL's radiological environmental monitoring program measured tritium in the air at on-site and off-site sampling stations. PPPL is capable of detecting small changes in the ambient levels of tritium by using highly sensitive monitors. The operation of an in-stack monitor located on D-site is a requirement of the National Emission Standard for Hazardous Air Pollutants (NESHAPs) regulations with limits set by the Environmental Protection Agency (EPA). Also included in PPPL's radiological environmental monitoring program, are precipitation, surface, ground, a nd

  14. 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.

    2012-10-15

    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.

  15. Staff Research Physicist (X-Ray Spectroscopy) | Princeton Plasma...

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

    of X-ray spectrometers for high energy density plasma at the National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory (LLNL, Livermore, California). In...

  16. Magnetized Target Fusion project with high density FRC at Los Alamos National Laboratory.

    SciTech Connect (OSTI)

    Intrator, T.; Park, J. Y.; Wurden, G. A.; Taccetti, J. M.; Tuszewski, M.; Zhang, S. Y.; Waganaar, W.; Furno, I.; Hsu, S.; Tejero, E.; Leonard, M.; Bass, C.; Grabowski, C.; Degnan, J. H.

    2003-08-13

    We describe a program to demonstrate the scientific basis of Magnetized Target Fusion (MTF). MTF is a potentially low cost path to fusion which is intermediate in plasma regime between magnetic (MFE) and inertial fusion energy (IFE). MTF involves the compression of a magnetized target plasma and PdV heating to fusion relevant conditions inside a converging flux conserving boundary. We have chosen to demonstrate MTF by using a field-reversed configuration (FRC) as our magnetized target plasma and an imploding metal liner for compression. These choices take advantage of significant past scientific and technical accomplishments in MFE and Defense Programs research and should yield substantial plasma performance (n{tau}>10{sup 13}s-cm{sup -3}>5 keV) using an available pulsed-power implosion facility at modest cost. We have recently shown this FRC to be within a factor of 2-3 of required pressure and lifetime.

  17. Measurement of a density profile of a hot-electron plasma in RT-1 with three-chord interferometry

    SciTech Connect (OSTI)

    Saitoh, H.; Yano, Y.; Yoshida, Z.; Nishiura, M.; Morikawa, J.; Kawazura, Y.; Nogami, T.; Yamasaki, M.

    2015-02-15

    The electron density profile of a plasma in a magnetospheric dipole field configuration was measured with a multi-chord interferometry including a relativistic correction. In order to improve the accuracy of density reconstruction, a 75 GHz interferometer was installed at a vertical chord of the Ring Trap 1 (RT-1) device in addition to previously installed ones at tangential and another vertical chords. The density profile was calculated by using the data of three-chord interferometry including relativistic effects for a plasma consisting of hot and cold electrons generated by electron cyclotron resonance heating (ECH). The results clearly showed the effects of density peaking and magnetic mirror trapping in a strongly inhomogeneous dipole magnetic field.

  18. Quantitative determination of mass-resolved ion densities in H{sub 2}-Ar inductively coupled radio frequency plasmas

    SciTech Connect (OSTI)

    Sode, M.; Schwarz-Selinger, T.; Jacob, W.

    2013-03-07

    Inductively coupled H{sub 2}-Ar plasmas are characterized by an energy-dispersive mass spectrometer (plasma monitor), a retarding field analyzer, optical emission spectroscopy, and a Langmuir probe. A procedure is presented that allows determining quantitatively the absolute ion densities of Ar{sup +}, H{sup +}, H{sub 2}{sup +}, H{sub 3}{sup +}, and ArH{sup +} from the plasma monitor raw signals. The calibration procedure considers the energy and mass-dependent transmission of the plasma monitor. It is shown that an additional diagnostic like a Langmuir probe or a retarding field analyzer is necessary to derive absolute fluxes with the plasma monitor. The conversion from fluxes into densities is based on a sheath and density profile model. Measurements were conducted for a total gas pressure of 1.0 Pa. For pure H{sub 2} plasmas, the dominant ion is H{sub 3}{sup +}. For mixed H{sub 2}-Ar plasmas, the ArH{sup +} molecular ion is the most dominant ion species in a wide parameter range. The electron density, n{sub e}, is around 3 Multiplication-Sign 10{sup 16} m{sup -3} and the electron temperature, T{sub e}, decreases from 5 to 3 eV with increasing Ar content. The dissociation degree was measured by actinometry. It is around 1.7% nearly independent on Ar content. The gas temperature, estimated by the rotational distribution of the Q-branch lines of the H{sub 2} Fulcher-{alpha} diagonal band (v Prime =v Double-Prime =2) is estimated to (540 {+-} 50) K.

  19. FY93 Princeton Plasma Physics Laboratory. Annual report, October 1, 1992--September 30, 1993

    SciTech Connect (OSTI)

    Not Available

    1995-02-01

    This is the annual report from the Princeton Plasma Physics Laboratory for the period October 1, 1992 to September 30, 1993. The report describes work done on TFTR during the year, as well as preparatory to beginning of D-T operations. Design work is ongoing on the Tokamak Physics Experiment (TPX) which is to test very long pulse operations of tokamak type devices. PBX has come back on line with additional ion-Bernstein power and lower-hybrid current drive. The theoretical program is also described, as well as other small scale programs, and the growing effort in collaboration on international design projects on ITER and future collaborations at a larger scale.

  20. Comparison of plasma temperature and electron density on nanosecond laser ablation of Cu and nano-Cu

    SciTech Connect (OSTI)

    Chen, Anmin; Jiang, Yuanfei; Wang, Tingfeng; Shao, Junfeng; Jin, Mingxing

    2015-03-15

    Laser-induced breakdown spectroscopy is performed through the collection of spectra by spectral detection equipment at different delay times and distances from targets composed of Cu and nano-Cu, which are ablated using a Nd:YAG laser (532 nm, 10 ns, 10 Hz) in our experiments. The measured wavelength range is from 475 nm to 525 nm. Using the local thermodynamic equilibrium model, we analyze the characteristics of the plasma temperature and the electron number density for different distances between the target surface and the lens. The results show that when compared with the nano-Cu plasma case, the temperature of the Cu plasma is higher, while its electron number density is lower.

  1. Laboratory

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

    performance computer system installed at Los Alamos National Laboratory June 17, 2014 Unclassified 'Wolf' system to advance many fields of science LOS ALAMOS, N.M., June 17, 2014-Los Alamos National Laboratory recently installed a new high-performance computer system, called Wolf, which will be used for unclassified research. "This machine modernizes our mid-tier resources available to Laboratory scientists," said Bob Tomlinson, of the Laboratory's High Performance Computing group.

  2. Environmental Survey preliminary report, Princeton Plasma Physics Laboratory, Princeton, New Jersey

    SciTech Connect (OSTI)

    Not Available

    1989-05-01

    This report presents the preliminary findings of the first phase of the Environmental Survey of the United States Department of Energy's (DOE) Princeton Plasma Physics Laboratory (PPPL), conducted June 13 through 17, 1988. The Survey is being conducted by an interdisciplinary team of environmental specialists, led and managed by the Office of Environment, Safety and Health's Office of Environmental Audit. Team members are being provided by private contractors. The objective of the Survey is to identify environmental problems and areas of environmental risk associated with PPPL. The Survey covers all environmental media and all areas of environmental regulation. It is being performed in accordance with the DOE Environmental Survey Manual. This phase of the Survey involves the review of existing site environmental data, observations of the operations carried on at PPPL, and interviews with site personnel. The Survey team developed a Sampling and Analysis (S A) Plan to assist in further assessing certain of the environment problems identified during its on-site activities. The S A plan is being developed by the Idaho National Engineering Laboratory. When completed, the S A results will be incorporated into the PPPL Survey findings for inclusion in the Environmental Survey Summary Report. 70 refs., 17 figs., 21 tabs.

  3. Convergence of statistical moments of particle density time series in scrape-off layer plasmas

    SciTech Connect (OSTI)

    Kube, R. Garcia, O. E.

    2015-01-15

    Particle density fluctuations in the scrape-off layer of magnetically confined plasmas, as measured by gas-puff imaging or Langmuir probes, are modeled as the realization of a stochastic process in which a superposition of pulses with a fixed shape, an exponential distribution of waiting times, and amplitudes represents the radial motion of blob-like structures. With an analytic formulation of the process at hand, we derive expressions for the mean squared error on estimators of sample mean and sample variance as a function of sample length, sampling frequency, and the parameters of the stochastic process. Employing that the probability distribution function of a particularly relevant stochastic process is given by the gamma distribution, we derive estimators for sample skewness and kurtosis and expressions for the mean squared error on these estimators. Numerically, generated synthetic time series are used to verify the proposed estimators, the sample length dependency of their mean squared errors, and their performance. We find that estimators for sample skewness and kurtosis based on the gamma distribution are more precise and more accurate than common estimators based on the method of moments.

  4. Whistler wave radiation from a pulsed loop antenna located in a cylindrical duct with enhanced plasma density

    SciTech Connect (OSTI)

    Kudrin, Alexander V.; Shkokova, Natalya M.; Ferencz, Orsolya E.; Zaboronkova, Tatyana M.

    2014-11-15

    Pulsed radiation from a loop antenna located in a cylindrical duct with enhanced plasma density is studied. The radiated energy and its distribution over the spatial and frequency spectra of the excited waves are derived and analyzed as functions of the antenna and duct parameters. Numerical results referring to the case where the frequency spectrum of the antenna current is concentrated in the whistler range are reported. It is shown that under ionospheric conditions, the presence of an artificial duct with enhanced density can lead to a significant increase in the energy radiated from a pulsed loop antenna compared with the case where the same source is immersed in the surrounding uniform magnetoplasma. The results obtained can be useful in planning active ionospheric experiments with pulsed electromagnetic sources operated in the presence of artificial field-aligned plasma density irregularities that are capable of guiding whistler waves.

  5. Princeton Plasma Physics Laboratory Annual Site Environmental Report for Calendar Year 2001

    SciTech Connect (OSTI)

    Virginia L. Finley

    2004-04-07

    The purpose of this report is to provide the U.S. Department of Energy (DOE) and the public with information on the level of radioactive and nonradioactive pollutants (if any) that are added to the environment as a result of the Princeton Plasma Physics Laboratory's (PPPL) operations. The results of the 2001 environmental surveillance and monitoring program for PPPL are presented and discussed. The report also summarizes environmental initiatives, assessments, and programs that were undertaken in 2001. PPPL has engaged in fusion energy research since 1951. The vision of the Laboratory is to create innovations to make fusion power a practical reality--a clean, alternative energy source. The Year 2001 marked the third year of National Spherical Torus Experiment (NSTX) operations and Tokamak Fusion Test Reactor (TFTR) dismantlement and deconstruction activities. A collaboration among fourteen national laboratories, universities, and research institutions, the NSTX is a major element in the U.S. Fusion Energy Sciences Program. It has been designed to test the physics principles of spherical torus (ST) plasmas. The ST concept could play an important role in the development of smaller, more economical fusion reactors. In 2001, PPPL's radiological environmental monitoring program measured tritium in the air at on- and off-site sampling stations. PPPL is capable of detecting small changes in the ambient levels of tritium by using highly sensitive monitors. The operation of an in-stack monitor located on D-site is a requirement of the National Emission Standard for Hazardous Air Pollutants (NESHAPs) regulations; also included in PPPL's radiological environmental monitoring program, are water monitoring--precipitation, ground-, surface-, and waste-waters. PPPL's radiological monitoring program characterized the ambient, background levels of tritium in the environment and from the D-site stack; the data are presented in this report. Groundwater monitoring continue d under a

  6. Argon–germane in situ plasma clean for reduced temperature Ge on Si epitaxy by high density plasma chemical vapor deposition

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Douglas, Erica A.; Sheng, Josephine J.; Verley, Jason C.; Carroll, Malcolm S.

    2015-06-04

    We found that the demand for integration of near infrared optoelectronic functionality with silicon complementary metal oxide semiconductor (CMOS) technology has for many years motivated the investigation of low temperature germanium on silicon deposition processes. Our work describes the development of a high density plasma chemical vapor deposition process that uses a low temperature (<460 °C) in situ germane/argon plasma surface preparation step for epitaxial growth of germanium on silicon. It is shown that the germane/argon plasma treatment sufficiently removes SiOx and carbon at the surface to enable germanium epitaxy. Finally, the use of this surface preparation step demonstrates anmore » alternative way to produce germanium epitaxy at reduced temperatures, a key enabler for increased flexibility of integration with CMOS back-end-of-line fabrication.« less

  7. Argon–germane in situ plasma clean for reduced temperature Ge on Si epitaxy by high density plasma chemical vapor deposition

    SciTech Connect (OSTI)

    Douglas, Erica A.; Sheng, Josephine J.; Verley, Jason C.; Carroll, Malcolm S.

    2015-06-04

    We found that the demand for integration of near infrared optoelectronic functionality with silicon complementary metal oxide semiconductor (CMOS) technology has for many years motivated the investigation of low temperature germanium on silicon deposition processes. Our work describes the development of a high density plasma chemical vapor deposition process that uses a low temperature (<460 °C) in situ germane/argon plasma surface preparation step for epitaxial growth of germanium on silicon. It is shown that the germane/argon plasma treatment sufficiently removes SiOx and carbon at the surface to enable germanium epitaxy. Finally, the use of this surface preparation step demonstrates an alternative way to produce germanium epitaxy at reduced temperatures, a key enabler for increased flexibility of integration with CMOS back-end-of-line fabrication.

  8. 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. [Universit de Toulouse, UPS, INPT, LAPLACE (Laboratoire Plasma et Conversion dnergie), 118 route de Narbonne, F-31062 Toulouse Cedex 9, France and CNRS, LAPLACE, F-31062, Toulouse (France)] [Universit de Toulouse, UPS, INPT, LAPLACE (Laboratoire Plasma et Conversion dnergie), 118 route de Narbonne, F-31062 Toulouse Cedex 9, France and CNRS, LAPLACE, F-31062, Toulouse (France)

    2013-08-15

    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.

  9. Modified Korteweg-deVries soliton evolution at critical density of negative ions in an inhomogeneous magnetized cold plasma

    SciTech Connect (OSTI)

    Singh, Dhananjay K.; Malik, Hitendra K.

    2007-06-15

    Soliton propagation at critical density of negative ions is studied for weakly inhomogeneous magnetized cold plasma having positive ions, negative ions, and electrons. A general phase velocity relation is obtained and possible modes are studied for different cases involving different constituents of the plasma. Two types of modes (fast and slow) are found to propagate for the equal mass of the positive and negative ions. However, a limit on the obliqueness of magnetic field is obtained for the propagation of slow mode. For both types of modes, a variable coefficient modified Korteweg-deVries equation with an additional term arisen due to the density gradient is realized, which admits solutions for compressive solitons and rarefactive solitons of the same amplitudes at critical negative ion density. The propagation characteristics of these solitons are studied under the effect of densities of ions, magnetic field, and its obliqueness. The amplitudes of fast and slow wave solitons show their opposite behavior with the negative ion concentration, which is consistent with the variation of phase velocities with the negative ion density.

  10. Density and x-ray emission profile relationships in highly ionized high-Z laser-produced plasmas

    SciTech Connect (OSTI)

    Yoshida, Kensuke; Fujioka, Shinsuke Ugomori, Teruyuki; Tanaka, Nozomi; Azechi, Hiroshi; Nishimura, Hiroaki; Higashiguchi, Takeshi Kawasaki, Masato; Suzuki, Yuhei; Suzuki, Chihiro; Tomita, Kentaro; Hirose, Ryoichi; Ejima, Takeo; Ohashi, Hayato; Nishikino, Masaharu; Sunahara, Atsushi; Li, Bowen; Dunne, Padraig; O'Sullivan, Gerry; Yanagida, Tatsuya

    2015-03-23

    We present a benchmark measurement of the electron density profile in the region where the electron density is 10{sup 19?}cm{sup 3} and where the bulk of extreme ultraviolet (EUV) emission occurs from isotropically expanding spherical high-Z gadolinium plasmas. It was found that, due to opacity effects, the observed EUV emission is mostly produced from an underdense region. We have analyzed time-resolved emission spectra with the aid of atomic structure calculations and find the multiple ion charge states around 18+ during the laser pulse irradiation.

  11. Laboratory

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

    Builders place final beam in first phase of CMRR project at Los Alamos National Laboratory July 22, 2008 LOS ALAMOS, New Mexico, July 22, 2008- Workers hoisted the final steel beam ...

  12. Laboratory

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

    Forest fire near Los Alamos National Laboratory June 26, 2011 Los Alamos, New Mexico, June 26, 2011, 6:07pm-The Las Conchas fire burning in the Jemez Mountains approximately 12...

  13. Plasma heating power dissipation in low temperature hydrogen plasmas

    SciTech Connect (OSTI)

    Komppula, J. Tarvainen, O.

    2015-10-15

    A theoretical framework for power dissipation in low temperature plasmas in corona equilibrium is developed. The framework is based on fundamental conservation laws and reaction cross sections and is only weakly sensitive to plasma parameters, e.g., electron temperature and density. The theory is applied to low temperature atomic and molecular hydrogen laboratory plasmas for which the plasma heating power dissipation to photon emission, ionization, and chemical potential is calculated. The calculated photon emission is compared to recent experimental results.

  14. 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.

    2014-03-15

    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.

  15. Princeton University Plasma Physics Laboratory, Princeton, New Jersey. Annual report, October 1, 1990--September 30, 1991

    SciTech Connect (OSTI)

    Not Available

    1991-12-31

    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.

  16. Generating end plug potentials in tandem mirror plasma confinement by heating thermal particles so as to escape low density end stoppering plasmas

    DOE Patents [OSTI]

    Baldwin, David E.; Logan, B. Grant

    1981-01-01

    The invention provides a method and apparatus for raising the potential of a magnetic mirror cell by pumping charged particles of the opposite sign of the potential desired out of the mirror cell through excitation, with the pumping being done by an externally imposed field at the bounce frequency of the above charged particles. These pumped simple mirror cells then provide end stoppering for a center mirror cell for the tandem mirror plasma confinement apparatus. For the substantially complete pumping case, the end plugs of a tandem mirror can be up to two orders of magnitude lower in density for confining a given center mirror cell plasma than in the case of end plugs without pumping. As a result the decrease in recirculating power required to keep the system going, the technological state of the art required, and the capital cost are all greatly lowered.

  17. Generating end plug potentials in tandem mirror plasma confinement by heating thermal particles so as to escape low density end stoppering plasmas

    DOE Patents [OSTI]

    Baldwin, D.E.; Logan, B.G.

    The invention provides a method and apparatus for raising the potential of a magnetic mirror cell by pumping charged particles of the opposite sign of the potential desired out of the mirror cell through excitation, with the pumping being done by an externally imposed field at the bounce frequence of the above charged particles. These pumped simple mirror cells then provide end stoppering for a center mirror cell for the tandem mirror plasma confinement apparatus. For the substantially complete pumping case, the end plugs of a tandem mirror can be up to two orders of magnitude lower in density for confining a given center mirror cell plasma than in the case of end plugs without pumping. As a result the decrease in recirculating power required to keep the system going, the technical state of the art required, and the capital cost are all greatly lowered.

  18. One-dimensional time-dependent fluid model of a very high density low-pressure inductively coupled plasma

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Chaplin, Vernon H.; Bellan, Paul M.

    2015-12-28

    A time-dependent two-fluid model has been developed to understand axial variations in the plasma parameters in a very high density (peak ne~ > 5x1019 m–3) argon inductively coupled discharge in a long 1.1 cm radius tube. The model equations are written in 1D, with radial losses to the tube walls accounted for by the inclusion of effective particle and energy sink terms. The ambipolar diffusion equation and electron energy equation are solved to find the electron density ne(z,t) and temperature Te(z,t), and the populations of the neutral argon 4s metastable, 4s resonant, and 4p excited state manifolds are calculated inmore » order to determine the stepwise ionization rate and calculate radiative energy losses. The model has been validated through comparisons with Langmuir probe ion saturation current measurements; close agreement between the simulated and measured axial plasma density profiles and the initial density rise rate at each location was obtained at pAr = 30-60 mTorr. Lastly, we present detailed results from calculations at 60 mTorr, including the time-dependent electron temperature, excited state populations, and energy budget within and downstream of the radiofrequency (RF) antenna.« less

  19. Soliton propagation in an inhomogeneous plasma at critical density of negative ions: Effects of gyratory and thermal motions of ions

    SciTech Connect (OSTI)

    Malik, Hitendra K.; Kawata, Shigeo

    2007-10-15

    The effects of gyratory and thermal motions of ions on soliton propagation in an inhomogeneous plasma that contains positive ions, negative ions, and electrons are studied at a critical density of negative ions. Since at this critical negative ion density the nonlinear term of the relevant Korteweg-deVries (KdV) equation vanishes, a higher order of nonlinearity is considered by retaining higher-order perturbation terms in the expansion of dependent quantities together with the appropriate set of stretched coordinates. Under this situation, time-dependent perturbation leads to the evolution of modified KdV solitons, which are governed by a modified form of the KdV equation that has an additional term due to the density gradient present in the plasma. On the basis of the solution of this equation and obliquely applied magnetic field, the effects of gyratory and thermal motions of ions are analyzed on the soliton propagation for three cases, n{sub n0}n{sub e0}, together with n{sub n0} (n{sub e0}) as the density of negative ions (electrons). The role of the negative ions in the evolution of the modes and the solitons is also discussed. Under the limiting cases, our calculations reduce to the ones obtained by other investigators in the past. This substantiates the generality of the present analysis.

  20. One-dimensional time-dependent fluid model of a very high density low-pressure inductively coupled plasma

    SciTech Connect (OSTI)

    Chaplin, Vernon H.; Bellan, Paul M.

    2015-12-28

    A time-dependent two-fluid model has been developed to understand axial variations in the plasma parameters in a very high density (peak ne~ > 5x1019 m–3) argon inductively coupled discharge in a long 1.1 cm radius tube. The model equations are written in 1D, with radial losses to the tube walls accounted for by the inclusion of effective particle and energy sink terms. The ambipolar diffusion equation and electron energy equation are solved to find the electron density ne(z,t) and temperature Te(z,t), and the populations of the neutral argon 4s metastable, 4s resonant, and 4p excited state manifolds are calculated in order to determine the stepwise ionization rate and calculate radiative energy losses. The model has been validated through comparisons with Langmuir probe ion saturation current measurements; close agreement between the simulated and measured axial plasma density profiles and the initial density rise rate at each location was obtained at pAr = 30-60 mTorr. Lastly, we present detailed results from calculations at 60 mTorr, including the time-dependent electron temperature, excited state populations, and energy budget within and downstream of the radiofrequency (RF) antenna.

  1. Inductively Driven, 3D Liner Compression of a Magnetized Plasma to Megabar Energy Densities

    SciTech Connect (OSTI)

    Slough, John

    2015-02-01

    To take advantage of the smaller scale, higher density regime of fusion an efficient method for achieving the compressional heating required to reach fusion gain conditions must be found. What is proposed is a more flexible metallic liner compression scheme that minimizes the kinetic energy required to reach fusion. It is believed that it is possible to accomplish this at sub-megajoule energies. This however will require operation at very small scale. To have a realistic hope of inexpensive, repetitive operation, it is essential to have the liner kinetic energy under a megajoule which allows for the survivability of the vacuum and power systems. At small scale the implosion speed must be reasonably fast to maintain the magnetized plasma (FRC) equilibrium during compression. For limited liner kinetic energy, it becomes clear that the thinnest liner imploded to the smallest radius consistent with the requirements for FRC equilibrium lifetime is desired. The proposed work is directed toward accomplishing this goal. Typically an axial (Z) current is employed for liner compression. There are however several advantages to using a θ-pinch coil. With the θ-pinch the liner currents are inductively driven which greatly simplifies the apparatus and vacuum system, and avoids difficulties with the post implosion vacuum integrity. With fractional flux leakage, the foil liner automatically provides for the seed axial compression field. To achieve it with optimal switching techniques, and at an accelerated pace however will require additional funding. This extra expense is well justified as the compression technique that will be enabled by this funding is unique in the ability to implode individual segments of the liner at different times. This is highly advantageous as the liner can be imploded in a manner that maximizes the energy transfer to the FRC. Production of shaped liner implosions for additional axial compression can thus be readily accomplished with the modified power

  2. Enhanced relativistic self-focusing of Hermite-cosh-Gaussian laser beam in plasma under density transition

    SciTech Connect (OSTI)

    Nanda, Vikas; Kant, Niti

    2014-04-15

    Enhanced and early relativistic self-focusing of Hermite-cosh-Gaussian (HChG) beam in the plasmas under density transition has been investigated theoretically using Wentzel-Kramers-Brillouin and paraxial ray approximation for mode indices m=0, 1, and 2. The variation of beam width parameter with normalized propagation distance for m=0, 1, and 2 is reported, and it is observed that strong self-focusing occurs as the HChG beam propagates deeper inside the nonlinear medium as spot size shrinks due to highly dense plasmas and the results are presented graphically. A comparative study between self-focusing of HChG beam in the presence and absence of plasmas density transition is reported. The dependency of beam width parameter on the normalized propagation distance for different values of decentered parameter “b” has also been presented graphically. For m=0 and 1, strong self-focusing is reported for b=1.8, and for m=2 and b=1.8, beam gets diffracted. The results obtained indicate the dependency of the self-focusing of the HChG beam on the selected values of decentered parameter. Moreover, proper selection of decentered parameter results strong self-focusing of HChG beam. Stronger self-focusing of laser beam is observed due to the presence of plasma density transition which might be very useful in the applications like the generation of inertial fusion energy driven by lasers, laser driven accelerators, etc.

  3. Study of energy conversion and partitioning in the magnetic reconnection layer of a laboratory plasma

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Yamada, Masaaki; Yoo, Jongsoo; Jara-Almonte, Jonathan; Daughton, William; Ji, Hantao; Kulsrud, Russell M.; Myers, Clayton E.

    2015-05-15

    The most important feature of magnetic reconnection is that it energizes plasma particles by converting magnetic energy to particle energy, the exact mechanisms by which this happens are yet to be determined despite a long history of reconnection research. Recently, we have reported our results on the energy conversion and partitioning in a laboratory reconnection layer in a short communication [Yamada et al., Nat. Commun. 5, 4474 (2014)]. The present paper is a detailed elaboration of this report together with an additional dataset with different boundary sizes. Our experimental study of the reconnection layer is carried out in the two-fluidmore » physics regime where ions and electrons move quite differently. We have observed that the conversion of magnetic energy occurs across a region significantly larger than the narrow electron diffusion region. A saddle shaped electrostatic potential profile exists in the reconnection plane, and ions are accelerated by the resulting electric field at the separatrices. These accelerated ions are then thermalized by re-magnetization in the downstream region. A quantitative inventory of the converted energy is presented in a reconnection layer with a well-defined, variable boundary. We also carried out a systematic study of the effects of boundary conditions on the energy inventory. This study concludes that about 50% of the inflowing magnetic energy is converted to particle energy, 2/3 of which is ultimately transferred to ions and 1/3 to electrons. When assisted by another set of magnetic reconnection experiment data and numerical simulations with different sizes of monitoring box, it is also observed that the observed features of energy conversion and partitioning do not depend on the size of monitoring boundary across the range of sizes tested from 1.5 to 4 ion skin depths.« less

  4. Study of energy conversion and partitioning in the magnetic reconnection layer of a laboratory plasma

    SciTech Connect (OSTI)

    Yamada, Masaaki; Yoo, Jongsoo; Jara-Almonte, Jonathan; Daughton, William; Ji, Hantao; Kulsrud, Russell M.; Myers, Clayton E.

    2015-05-15

    The most important feature of magnetic reconnection is that it energizes plasma particles by converting magnetic energy to particle energy, the exact mechanisms by which this happens are yet to be determined despite a long history of reconnection research. Recently, we have reported our results on the energy conversion and partitioning in a laboratory reconnection layer in a short communication [Yamada et al., Nat. Commun. 5, 4474 (2014)]. The present paper is a detailed elaboration of this report together with an additional dataset with different boundary sizes. Our experimental study of the reconnection layer is carried out in the two-fluid physics regime where ions and electrons move quite differently. We have observed that the conversion of magnetic energy occurs across a region significantly larger than the narrow electron diffusion region. A saddle shaped electrostatic potential profile exists in the reconnection plane, and ions are accelerated by the resulting electric field at the separatrices. These accelerated ions are then thermalized by re-magnetization in the downstream region. A quantitative inventory of the converted energy is presented in a reconnection layer with a well-defined, variable boundary. We also carried out a systematic study of the effects of boundary conditions on the energy inventory. This study concludes that about 50% of the inflowing magnetic energy is converted to particle energy, 2/3 of which is ultimately transferred to ions and 1/3 to electrons. When assisted by another set of magnetic reconnection experiment data and numerical simulations with different sizes of monitoring box, it is also observed that the observed features of energy conversion and partitioning do not depend on the size of monitoring boundary across the range of sizes tested from 1.5 to 4 ion skin depths.

  5. Excitation of electrostatic waves in the electron cyclotron frequency range during magnetic reconnection in laboratory overdense plasmas

    SciTech Connect (OSTI)

    Kuwahata, A.; Igami, H.; Kawamori, E.; Kogi, Y.; Inomoto, M.; Ono, Y.

    2014-10-15

    We report the observation of electromagnetic radiation at high harmonics of the electron cyclotron frequency that was considered to be converted from electrostatic waves called electron Bernstein waves (EBWs) during magnetic reconnection in laboratory overdense plasmas. The excitation of EBWs was attributed to the thermalization of electrons accelerated by the reconnection electric field around the X-point. The radiative process discussed here is an acceptable explanation for observed radio waves pulsation associated with major flares.

  6. Understanding the dynamics and energetics of magnetic reconnection in a laboratory plasma: Review of recent progress on selected fronts

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Yamada, Masaaki; Yoo, Jongsoo; Myers, Clayton E.

    2016-05-11

    Here, magnetic reconnection is a fundamental process at work in laboratory, space, and astrophysical plasmas, in which magnetic field lines change their topology and convert magnetic energy to plasma particles by acceleration and heating. One of the most important problems in reconnection research has been to understand why reconnection occurs so much faster than predicted by magnetohydrodynamics theory. Following the recent pedagogical review of this subject [Yamada et al., Rev. Mod. Phys. 82, 603 (2010)], this paper presents a review of more recent discoveries and findings in the research of fast magnetic reconnection in laboratory, space, and astrophysical plasmas. Inmore » spite of the huge difference in physical scales, we find remarkable commonality between the characteristics of the magnetic reconnection in laboratory and space plasmas. In this paper, we will focus especially on the energy flow, a key feature of the reconnection process. In particular, the experimental results on the energy conversion and partitioning in a laboratory reconnection layer [Yamada et al., Nat. Commun. 5, 4474 (2014)] are discussed and compared with quantitative estimates based on two-fluid analysis. In the Magnetic ReconnectionExperiment, we find that energy deposition to electrons is localized near the X-point and is mostly from the electric field component perpendicular to the magnetic field. The mechanisms of ion acceleration and heating are also identified, and a systematic and quantitative study on the inventory of converted energy within a reconnection layer with a well-defined but variable boundary. The measured energy partition in a reconnection region of similar effective size (L ≈ 3 ion skin depths) of the Earth's magneto-tail [Eastwood et al., Phys. Rev. Lett. 110, 225001 (2013)] is notably consistent with our laboratory results. Finally, to study the global aspects of magnetic reconnection, we have carried out a laboratory experiment on the stability criteria for

  7. First beam measurements on the vessel for extraction and source plasma analyses (VESPA) at the Rutherford Appleton Laboratory (RAL)

    SciTech Connect (OSTI)

    Lawrie, Scott R.; Faircloth, Daniel C.; Letchford, Alan P.; Perkins, Mike; Whitehead, Mark O.; Wood, Trevor

    2015-04-08

    In order to facilitate the testing of advanced H{sup −} ion sources for the ISIS and Front End Test Stand (FETS) facilities at the Rutherford Appleton Laboratory (RAL), a Vessel for Extraction and Source Plasma Analyses (VESPA) has been constructed. This will perform the first detailed plasma measurements on the ISIS Penning-type H{sup −} ion source using emission spectroscopic techniques. In addition, the 30-year-old extraction optics are re-designed from the ground up in order to fully transport the beam. Using multiple beam and plasma diagnostics devices, the ultimate aim is improve H{sup −} production efficiency and subsequent transport for either long-term ISIS user operations or high power FETS requirements. The VESPA will also accommodate and test a new scaled-up Penning H{sup −} source design. This paper details the VESPA design, construction and commissioning, as well as initial beam and spectroscopy results.

  8. Laboratory

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

    Mexican pueblo preserves cultural history through collaborative tours with Los Alamos National Laboratory August 24, 2015 Students gain new insights into their ancestry LOS ALAMOS, N.M., Aug. 24, 2015-San Ildefonso Pueblo's Summer Education Enhancement Program brought together academic and cultural learning in the form of a recent tour of Cave Kiva Trail in Mortandad Canyon."Opening up this archaeological site and sharing it with the descendants of its first inhabitants is a

  9. Impact of the pedestal plasma density on dynamics of edge localized mode crashes and energy loss scaling

    SciTech Connect (OSTI)

    Xu, X. Q.; Ma, J. F.; Li, G. Q.

    2014-12-15

    The latest BOUT++ studies show an emerging understanding of dynamics of edge localized mode (ELM) crashes and the consistent collisionality scaling of ELM energy losses with the world multi-tokamak database. A series of BOUT++ simulations are conducted to investigate the scaling characteristics of the ELM energy losses vs collisionality via a density scan. Linear results demonstrate that as the pedestal collisionality decreases, the growth rate of the peeling-ballooning modes decreases for high n but increases for low n (1?plasma and yields an increasing ELM size with decreasing collisionality after a series of micro-bursts. The pedestal plasma density plays a major role in determining the ELM energy loss through its effect on the edge bootstrap current and ion diamagnetic stabilization. The critical trend emerges as a transition (1) linearly from ballooning-dominated states at high collisionality to peeling-dominated states at low collisionality with decreasing density and (2) nonlinearly from turbulence spreading dynamics at high collisionality into avalanche-like dynamics at low collisionality.

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

    SciTech Connect (OSTI)

    Laity, George; Fierro, Andrew; Dickens, James; Neuber, Andreas; Frank, Klaus

    2014-03-28

    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.

  11. Impact of the pedestal plasma density on dynamics of edge localized mode crashes and energy loss scaling

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Xu, X. Q.; Ma, J. F.; Li, G. Q.

    2014-12-29

    The latest BOUT++ studies show an emerging understanding of dynamics of edge localized mode(ELM) crashes and the consistent collisionality scaling of ELMenergy losses with the world multi-tokamak database. A series of BOUT++ simulations are conducted to investigate the scaling characteristics of the ELMenergy losses vs collisionality via a density scan. Moreover, the linear results demonstrate that as the pedestal collisionality decreases, the growth rate of the peeling-ballooning modes decreases for high n but increases for low n (1 < n < 5), therefore the width of the growth rate spectrum γ(n) becomes narrower and the peak growth shifts to lowermore » n. For nonlinear BOUT++ simulations show a two-stage process of ELM crash evolution of (i) initial bursts of pressure blob and void creation and (ii) inward void propagation. The inward void propagation stirs the top of pedestal plasma and yields an increasing ELM size with decreasing collisionality after a series of micro-bursts. The pedestal plasma density plays a major role in determining the ELMenergy loss through its effect on the edge bootstrap current and ion diamagnetic stabilization. Finally, the critical trend emerges as a transition (1) linearly from ballooning-dominated states at high collisionality to peeling-dominated states at low collisionality with decreasing density and (2) nonlinearly from turbulence spreading dynamics at high collisionality into avalanche-like dynamics at low collisionality.« less

  12. Development of an x-ray Talbot-Lau moire deflectometer for fast density profile measurements of dense plasmas generated by beam-target interactions

    SciTech Connect (OSTI)

    Clayton, Dan; Berninger, M; Meidinger, A; Stutman, Dan; Valdivia, Maria Pia

    2015-05-01

    For the first time an x-ray Talbot-Lau moire deflectometer is being developed that will use a flash tube source and fast detector for dynamic density gradient measurements. In Talbot-Lau moire deflectometry, an x-ray grating makes an image of itself on a second grating (the Talbot effect) to produce a moire pattern on a detector. The test object is placed between these gratings, with variations in index of refraction changing the pattern. A third grating in front of an incoherent x-ray source produces an array of coherent sources. With a 150 kV x-ray flash tube as the source, the gratings are placed in a glancing angle setup for performance at ~60 keV. The detector is a gated CCD with a fast scintillator for x-ray conversion. This diagnostic, designed for the Dual-Axis Radiographic Hydrodynamic Test facility (DARHT) at Los Alamos National Laboratory, measures the density profile of dense plasma plumes ejected from beam-target interactions. DARHT has two high-current, pulsed, inductive linear electron accelerators with bremsstrahlung targets at the end of each beam line to create 2-D radiographic images of hydrodynamic tests. One multi-pulse accelerator has up to four beam pulses striking the same target within 2 μs. Computer simulations that model target evolution and ejected material between pulses are used to design these targets for optimal radiographic performance; the x-ray deflectometer will directly measure density gradients in the ejected plumes and provide the first experimental constraints to these models. During the first year, currently underway, the diagnostic systems are being designed. In year two, the flash tube and fast detector will be deployed at DARHT for radiographic imaging while the deflectometer is built and tested on the bench with a continuous source. Finally, in year three, the fast deflectometer will be installed on DARHT and density measurements will be performed.

  13. Electron acceleration by laser wakefield and x-ray emission at moderate intensity and density in long plasmas

    SciTech Connect (OSTI)

    Ferrari, H. E.; Lifschitz, A. F.; Maynard, G.; Cros, B.

    2011-08-15

    The dynamics of electron acceleration by laser wakefield and the associated x-rays emission in long plasmas are numerically investigated for parameters close to the threshold of laser self-focusing. The plasma length is set by the use of dielectric capillary tubes that confine the gas and the laser energy. Electrons self-injection and acceleration to the 170 MeVs are obtained for densities as low as 5 x 10{sup 18} cm{sup -3} and a moderate input intensity (0.77 x 10{sup 18} W/cm{sup 2}). The associated x-ray emission at the exit of the capillary tube is shown to be an accurate diagnostic of the electrons self-injection and acceleration process.

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

    SciTech Connect (OSTI)

    Solomon, Wayne M.; Snyder, P. B.; Burrell, K. H.; Fenstermacher, M. E.; Garofalo, A. M.; Grierson, B. A.; Loarte, A.; McKee, G. R.; Nazikian, R; Osborne, T. H.

    2014-07-01

    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.

  15. 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

    2009-01-01

    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.

  16. Studies on soliton energy at critical and noncritical densities of negative ions in an inhomogeneous magnetized warm plasma

    SciTech Connect (OSTI)

    Singh, Dhananjay K.; Malik, Hitendra K.

    2007-11-15

    Considering an inhomogeneous plasma having finite-temperature negative and positive ions, and the isothermal electrons in the presence of an external magnetic field, the solitons at noncritical and critical densities of the negative ions are studied through Korteweg-deVries (KdV) and modified Korteweg-deVries (mKdV) equations, respectively. The compressive (rarefactive) KdV solitons are found to propagate when the negative ion concentration is less (greater) than the critical density of the negative ions. At the critical density, both the compressive and the rarefactive solitons of equal amplitudes are found to occur. The energies of the compressive KdV soliton and the mKdV solitons are found to increase and that of the rarefactive KdV soliton is found to decrease with the negative ion density. Soliton energy for both the KdV and the mKdV solitons gets lowered under the effect of stronger magnetic field. The effect of ion temperature is to increase the energy of the compressive KdV soliton, whereas the energy of the rarefactive KdV soliton as well as of the mKdV solitons gets decreased. The variation of the energy with the obliqueness of the magnetic field is different for the KdV and the mKdV solitons.

  17. Princeton Plasma Physics Laboratory annual report, October 1, 1991--September 30, 1992

    SciTech Connect (OSTI)

    Not Available

    1992-12-31

    This report discusses the following topics: Principal parameters achieved in experimental devices for fiscal year 1992; tokamak fusion test reactor; princeton beta experiment-modification; current drive experiment-upgrade; tokamak physics experiment/steady-state advanced tokamak; international thermonuclear experimental reactor; international collaboration; x-ray laser studies; plasma processing: Deposition and etching of thin films; pure electron plasma experiments; theoretical studies; tokamak modeling; high-field magnet project; engineering department; environment, safety, and health and quality assurance; technology transfer; office of human resources and administration; PPPL invention disclosures for fiscal year 1992; office of resource management; graduate education: plasma physics; graduate education: program in plasma science and technology; and science education program.

  18. A Q&A With the Director of the Princeton Plasma Physics Laboratory...

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

    ... Contact Info PPPL Office of Communications Email: PPPLOOC@pppl.gov Phone: 609-243-2755 Download Select and View High Resolution Images to Download Learn More Fusion energy Plasma ...

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

    SciTech Connect (OSTI)

    Weller, M. E. 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.; Apruzese, J. P.; Giuliani, J. L.; Chuvatin, A. S.

    2014-03-15

    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 3.55.0?. 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.

  20. Analytical description of generation of the residual current density in the plasma produced by a few-cycle laser pulse

    SciTech Connect (OSTI)

    Silaev, A. A. Vvedenskii, N. V.

    2015-05-15

    When a gas is ionized by a few-cycle laser pulse, some residual current density (RCD) of free electrons remains in the produced plasma after the passage of the laser pulse. This quasi-dc RCD is an initial impetus to plasma polarization and excitation of the plasma oscillations which can radiate terahertz (THz) waves. In this work, the analytical model for calculation of RCD excited by a few-cycle laser pulse is developed for the first time. The dependences of the RCD on the carrier-envelope phase (CEP), wavelength, duration, and intensity of the laser pulse are derived. It is shown that maximum RCD corresponding to optimal CEP increases with the laser pulse wavelength, which indicates the prospects of using mid-infrared few-cycle laser pulses in the schemes of generation of high-power THz pulses. Analytical formulas for optimal pulse intensity and maximum efficiency of excitation of the RCD are obtained. Basing on numerical solution of the 3D time-dependent Schrödinger equation for hydrogen atoms, RCD dependence on CEP is calculated in a wide range of wavelengths. High accuracy of analytical formulas is demonstrated at the laser pulse parameters which correspond to the tunneling regime of ionization.

  1. 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; Cheng, Cheng E-mail: paul.chu@cityu.edu.hk; Chu, Paul K. E-mail: paul.chu@cityu.edu.hk

    2014-05-15

    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.

  2. Princeton Plasma Physics Laboratory annual report, October 1, 1982-September 30, 1983

    SciTech Connect (OSTI)

    Phillips, C.A.

    1983-01-01

    The Tokamak Fusion Test Reactor (TFTR) achieved first plasma at 3:05 a.m. on December 24, 1982. During the course of the year, the plasma current was raised to a maximum of 1 MA, and extensive confinement studies were carried out with ohmic-heated plasmas. The most important finding was that tokamak energy confinement time increases as the cube of the plasma size. The Princeton Large Torus (PLT) carried out a number of high-powered plasma-heating experiments in the ion cyclotron frequency range, and also demonstrated for the first time that a 100-kA tokamak discharge can be built up by means of rf-waves in the lower hybrid range, without any need for inductive current drive by the conventional tokamak transformer system. The Poloidal Divertor Experiment (PDX) demonstrated that substantial improvements in plasma confinement during intense neutral-beam heating can be obtained by means of either a magnetic divertor or a mechanical scoop limiter. The S-1 spheromak experiment has come into operation, with first plasma in January 1983, and machine completion in August. The soft X-ray laser development experiment continues to make strong progress towards the demonstration of laser amplification. Thus far, a single-pass gain of 3.5 has been achieved, using the 182 A line of CVI. Theoretical MHD-stability studies have shed new light on the nature of the energetic-ion-driven ''fishbone instability,'' and the utilization of the bean-shaping technique to reach higher beta values in the tokamak.

  3. DESTRUCTION OF NEUTRAL PARTICLES IN A DEVICE FOR PRODUCING A HIGH DENSITY PLASMA

    DOE Patents [OSTI]

    Simon, A.

    1962-05-01

    A method and apparatus are described for burning out neutral particles in an evacuated region and within a strong magnetic field. The method comprises injecting energetic molecular ions into the region perpendicular to the magnetic field and into the path of a dissociating, energetic arc discharge, the atomic ions formed in the dissociating process being trapped by the magnetic field, and then increasing the value of the trapped atomic ion current to such a value that the neutral particles are destroyed faster than they are formed, thereby causing a dense, energetic plasma to be built up and sustained by the magnetic field. (AEC)

  4. Scattering of Radio Frequency Waves by Edge Density Blobs in Tokamak Plasmas

    SciTech Connect (OSTI)

    Ram, A. K.; Hizanidis, K.; Kominis, Y.

    2011-12-23

    The density blobs and fluctuations present in the edge region of magnetic fusion devices can scatter radio frequency (RF) waves through refraction and diffraction. The scattering can diffuse the rays in space and in wave-vector space. The diffusion in space can make the rays miss their intended target region, while the diffusion in wave-vector space can broaden the wave spectrum and modify the wave damping and current profile.

  5. THERMAL ANNEALING OF ZNO FILMS USING HIGH-DENSITY PLASMA ARC LAMPS

    SciTech Connect (OSTI)

    Sabau, Adrian S; Dinwiddie, Ralph Barton; Xu, Jun; Angelini, Joseph Attilio; Harper, David C

    2011-01-01

    Nanostructured materials are rarely synthesized with appropriate phase and/or morphology. In this study, critical additional of as-synthesized nanostructured materials, such as annealing and/or activation of dopants, are addressed using infrared plasma arc lamps (PAL) over areas as large as 1,000 cm2. The broad spectral range of the PAL and the spectral variation of light absorption in nanostructured materials make the selection of processing parameters extremely difficult, posing a major technological barrier. In this study, the measurement of the surface temperature using various techniques for ZnO films on crystalline silicon wafers is discussed. An energy transport model for the simulation of rapid thermal processing using PAL is presented. The experimental and computational results show that the surface temperature cannot be measured directly and that computer simulation results are an effective tool for obtaining accurate data on processing temperatures.

  6. A Radiative Transport Model for Heating Paints using High Density Plasma Arc Lamps

    SciTech Connect (OSTI)

    Sabau, Adrian S; Duty, Chad E; Dinwiddie, Ralph Barton; Nichols, Mark; Blue, Craig A; Ott, Ronald D

    2009-01-01

    The energy distribution and ensuing temperature evolution within paint-like systems under the influence of infrared radiation was studied. Thermal radiation effects as well as those due to heat conduction were considered. A complete set of material properties was derived and discussed. Infrared measurements were conducted to obtain experimental data for the temperature in the paint film. The heat flux of the incident radiation from the plasma arc lamp was measured using a heat flux sensor with a very short response time. The comparison between the computed and experimental results for temperature show that the models that are based on spectral four-flux RTE and accurate optical properties yield accurate results for the black paint systems.

  7. DIRECT RADIO PROBING AND INTERPRETATION OF THE SUN'S PLASMA DENSITY PROFILE

    SciTech Connect (OSTI)

    Cairns, I. H.; Lobzin, V. V.; Li, B.; Robinson, P. A.; Warmuth, A.; Mann, G.

    2009-12-01

    The Sun's electron number density profile n{sub e} (r) is vital for solar physics but not well measured or understood within a few solar radii R{sub S} . Here, a new technique extracts n{sub e} (r) directly from coronal type III radio bursts for 40 <= f <= 180 MHz. Unexpectedly, wind-like regions with n{sub e} propor to (r - R{sub S} ){sup -2} are quite common below 2R{sub S} , and coronal type IIIs often have closely linear 1/f - t spectra. The profile n{sub e} propor to (r - R{sub S} ){sup -2} is consistent with the radio data and simulations and is interpreted in terms of conical flow from localized sources (e.g., UV funnels) close to the photosphere. It is consistent with solar wind acceleration occurring for 2 <= r/R{sub S} <= 10.

  8. Refluxed electrons direct laser acceleration in ultrahigh laser and relativistic critical density plasma interaction

    SciTech Connect (OSTI)

    Wang, J.; Zhao, Z. Q.; Zhu, B.; Zhang, Z. M.; Zhou, W. M.; Gu, Y. Q.; Cao, L. H.

    2015-01-15

    Refluxed electrons direct laser acceleration is proposed so as to generate a high-charge energetic electron beam. When a laser pulse is incident on a relativistic critical density target, the rising edge of the pulse heats the target and the sheath fields on the both sides of the target reflux some electrons inside the expanding target. These electrons can be trapped and accelerated due to the self-transparency and the negative longitudinal electrostatic field in the expanding target. Some of the electrons can be accelerated to energies exceeding the ponderomotive limit 1/2a{sub 0}{sup 2}mc{sup 2}. Effective temperature significantly above the ponderomotive scaling is observed. Furthermore, due to the limited expanding length, the laser propagating instabilities are suppressed in the interaction. Thus, high collimated beams with tens of μC charge can be generated.

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

    SciTech Connect (OSTI)

    MacDonald, M. J. Gamboa, E. J.; 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.; Montgomery, D. S.; Biener, M. M.; Fournier, K. B.; Streit, J.

    2014-11-15

    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-α 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.

  10. Development of an x-ray Talbot-Lau moiré deflectometer for fast density profile measurements of dense plasmas generated by beam-target interactions

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Clayton, Dan; Berninger, M; Meidinger, A; Stutman, Dan; Valdivia, Maria Pia

    2015-05-01

    For the first time an x-ray Talbot-Lau moiré deflectometer is being developed that will use a flash tube source and fast detector for dynamic density gradient measurements. In Talbot-Lau moiré deflectometry, an x-ray grating makes an image of itself on a second grating (the Talbot effect) to produce a moiré pattern on a detector. The test object is placed between these gratings, with variations in index of refraction changing the pattern. A third grating in front of an incoherent x-ray source produces an array of coherent sources. With a 150 kV x-ray flash tube as the source, the gratings aremore » placed in a glancing angle setup for performance at ~60 keV. The detector is a gated CCD with a fast scintillator for x-ray conversion. This diagnostic, designed for the Dual-Axis Radiographic Hydrodynamic Test facility (DARHT) at Los Alamos National Laboratory, measures the density profile of dense plasma plumes ejected from beam-target interactions. DARHT has two high-current, pulsed, inductive linear electron accelerators with bremsstrahlung targets at the end of each beam line to create 2-D radiographic images of hydrodynamic tests. One multi-pulse accelerator has up to four beam pulses striking the same target within 2 μs. Computer simulations that model target evolution and ejected material between pulses are used to design these targets for optimal radiographic performance; the x-ray deflectometer will directly measure density gradients in the ejected plumes and provide the first experimental constraints to these models. During the first year, currently underway, the diagnostic systems are being designed. In year two, the flash tube and fast detector will be deployed at DARHT for radiographic imaging while the deflectometer is built and tested on the bench with a continuous source. Finally, in year three, the fast deflectometer will be installed on DARHT and density measurements will be performed.« less